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SKYLIGHT FIXTURE
Field of the Disclosure
[0001] The present disclosure relates to lighting fixtures and in
particular to
lighting fixtures that emulate skylights.
Background
[0002] A skylight is a window that is generally installed in a roof or
ceiling.
Skylights are excellent sources of natural light and highly desirable in many
residential and commercial buildings. Providing natural light to an area is
known
to enhance moods, increase productivity, and improve ambiance among many
other benefits. Skylights are often used to supplement the natural light in
spaces
with windows, and are often the only way to provide natural light to interior
spaces that are not abutting exterior walls.
[0003] Unfortunately, providing skylights in many spaces is impractical
or
impossible. The lower floors of a building will not have direct access to the
roof of
the building. In many cases, even the top floor of the building will have
structural
or mechanical components that prevent the installation of skylights, limit the
functionality of skylights, or would cause installation of the skylights to be
too
expensive.
[0004] Accordingly, there is a need to provide the benefits of skylights
to
those spaces where installation of skylights would be impractical or
impossible.
Summary
[0005] Disclosed is a lighting fixture that appears as a skylight and is
referred
to as a skylight fixture. The skylight fixture has a sky-resembling light
assembly
and a plurality of sun-resembling light assemblies. The sky-resembling light
assembly has a specific optical assembly and a specific light source, wherein
light from the light source exits a planar interior surface of the optical
assembly
as sky resembling light. The plurality of sun-resembling light assemblies are
arranged adjacent one another and extend downward from a periphery of the
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sky-resembling light assembly. Each of the plurality of sun-resembling light
assemblies has a specific optical assembly and a specific light source,
wherein
light from the light source exits a planar interior surface of the optical
assembly
as sun resembling light. The planar interior surfaces of the sky-resembling
optical
assembly and the plurality of sun-resembling optical assemblies define a
cavity.
One or more control modules alone or in a collective are configured to, in a
first
mode, drive the sky-specific light source and each sun-specific light sources
such
that the sky-resembling assembly has a light emission with a first color point
and
the at least one of the sun-resembling assemblies has light emission with a
second color point that is different from the first color point. The skylight
assembly may be configured to emulate a window of a traditional skylight. Each
of the plurality of sunlight assemblies may be configured to emulate sunlight
passing through and/or reflecting off of sidewalls of the traditional
skylight. The
interior surfaces need not be planar for either assembly for dome or other
shaped
skylight fixtures.
[0006] In one embodiment, one or both of the sky-specific light source
and the
sun-specific light source comprise first LEDs that emit light having a third
color
point, second LEDs that emit light having a fourth color point, and third LEDs
that
emit light having a fifth color point. In this embodiment or an independent
embodiment, an interior angle formed between the planar interior surface of
the
sky-resembling optical assembly and the planar surface of each of the sun-
resembling optical assembly is an obtuse angle. In various embodiments, the
interior angle is greater than 90 degrees and less than or equal to 135
degrees;
greater than or equal to 95 degrees and less than or equal to 130 degrees; or
.. greater than or equal to 100 degrees and less than or equal to 125 degrees.
[0007] In one embodiment, the x coordinate value of the first color
point and
the x coordinate value of the second color point on the 1931 CIE Chromaticity
Diagram differ by at least 0.1. The first color point falls within a first
color space
defined by x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.37,
0.34),
(0.35, 0.38), (0.15, 0.20), and (0.20, 0.14). The second color point falls
within a
second color space defined by x, y coordinates on the 1931 CIE Chromaticity
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Diagram: (0.29, 0.32), (0.32, 0.29), (0.41, 0.36), (0.48, 0.39), (0.48, 0.43),
(0.40,
0.41), and (0.35, 0.38).
[0008] In one embodiment, the x coordinate value of the first color
point and
the x coordinate value of the second color point on the 1931 CIE Chromaticity
Diagram differ by at least 0.1. The first color point falls within a first
color space
defined by x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.32,
0.31),
(0.30, 0.33), (0.15, 0.17), and (0.17, 0.14). The second color point falls
within a
second color space defined by x, y coordinates on the 1931 CIE Chromaticity
Diagram: (0.30, 0.34), (0.30, 0.30), (0.39, 0.36), (0.45, 0.39), (0.47, 0.43),
(0.40,
0.41), and (0.35, 0.38).
[0009] In one embodiment, the x coordinate value of the first color
point and
the x coordinate value of the second color point on the 1931 CIE Chromaticity
Diagram differ by at least 0.1. The first color point falls within a first
color space
defined by x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.39,
0.31),
(0.34, 0.40), (0.10, 0.20), and (0.16, 0.06). The second color point falls
within a
second color space defined by x, y coordinates on the 1931 CIE Chromaticity
Diagram: (0.28, 0.36), (0.35, 0.26), (0.44, 0.33), (0.62, 0.34), (0.50, 0.46),
(0.43,
0.45), (0.36, 0.43).
[0010] In one embodiment, the x coordinate value of the first color
point and
the x coordinate value of the second color point on the 1931 CIE Chromaticity
Diagram differ by at least 0.1. The first color point falls within a first
color space
defined by x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.10,
0.20),
(0.36, 0.43), (0.43, 0.45), (0.50, 0.46), (0.62, 0.34), (0.44, 0.33), (0.16,
0.06). The
second color point falls within a second color space defined by x, y
coordinates
on the 1931 CIE Chromaticity Diagram: (0.10, 0.20), (0.36, 0.43), (0.43,
0.45),
(0.50, 0.46), (0.62, 0.34), (0.44, 0.33), (0.16, 0.06).
[0011] In one embodiment, the x coordinate value of the first color
point and
the x coordinate value of the second color point on the 1931 CIE Chromaticity
Diagram differ by at least 0.15. In another embodiment, the x coordinate value
of
the first color point and the x coordinate value of the second color point on
the
1931 CIE Chromaticity Diagram differ by at least 0.2.
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[0012] In one embodiment, the x coordinate value of the first color
point is
less than the x coordinate value of the second color point on the 1931 CIE
Chromaticity Diagram. In another embodiment, the y coordinate value of the
first
color point is less than the y coordinate value of the second color point on
the
1931 CIE Chromaticity Diagram. In yet another embodiment, both the x
coordinate value of the first color point is less than the x coordinate value
of the
second color point on the 1931 CIE Chromaticity Diagram and they coordinate
value of the first color point is less than the y coordinate value of the
second
color point on the 1931 CIE Chromaticity Diagram. The x coordinate value of
the
first color point and the x coordinate value of the second color point on the
1931
CIE Chromaticity Diagram may differ by at least 0.15, 0.2, and 0.25.
[0013] In one embodiment, the sky-specific light source comprises first
LEDs
that emit light having a third color point, second LEDs that emit light having
a
fourth color point, and third LEDs that emit light having a fifth color point.
The
third color point, the fourth color point, and the fifth color point are
spaced apart
from one another on the 1931 CIE Chromaticity Diagram by at least 0.05 in at
least one of x and y directions. The first LEDs may emit white light, and the
third
color point may be within three, five, seven, or ten MacAdams Ellipses of a
blackbody curve. The second LEDs may emit bluish light, the third LEDs may
emit greenish light, and the y coordinate value of the fourth color point and
the y
coordinate value of the fifth color point on the 1931 CIE Chromaticity Diagram
may differ by at least 0.1, 0.15, or 0.2.
[0014] In one embodiment, at least two of the sun-specific light sources
may
have fourth LEDs that emit light having a sixth color point, fifth LEDs that
emit
light having a seventh color point, and sixth LEDs that emit light having an
eighth
color point. The sixth color point, the seventh color point, and the eighth
color
point may be spaced apart from one another on the 1931 CIE Chromaticity
Diagram by at least 0.05, 0.1, or 0.15 in at least one of x and y directions.
[0015] In one embodiment, at least two of the sun-specific light sources
have
first LEDs that emit light having a third color point, second LEDs that emit
light
having a fourth color point, and third LEDs that emit light having a fifth
color
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point. The third color point, the fourth color point, and the fifth color
point spaced
may be apart from one another on the 1931 CIE Chromaticity Diagram by at least
0.05, 0.1, or 0.15 in at least one of x and y directions.
[0016] In one embodiment, the sky-resembling light assembly and the sun-
5 resembling light assembly may provide a composite light output that has a
color
rendering index of greater than 90.
[0017] In one embodiment, the one or more control modules may be further
configured to independently and variably drive the sky-specific light source
and
each sun-specific source such that the first color point and the second color
point
are independently variable.
[0018] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point change
temporally.
[0019] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on a time of day.
[0020] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on information received from a remote device.
[0021] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on sensor information provided by at least one sensor.
[0022] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on outdoor lighting conditions.
6
[0023] In one embodiment, the one or more control modules may be
further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on outdoor weather conditions.
[0024] In one embodiment, the one or more control modules may be further
configured to drive the sky-specific light source and each sun-specific light
source such that the first color point and the second color point are selected
based on outdoor environmental conditions.
[0025] In one embodiment, the one or more control modules may be
further
configured to, in a second mode, drive the sky-specific light source and each
sun-specific light source to change the first and second color point to
provide a
circadian stimulus.
[0026] In one embodiment, the one or more control modules may be
further
configured to, in a second mode, drive each sunlight light source to change
the
second color point of the sunlight light provided by each sunlight source to
have
additional red spectral content.
[0027] In one embodiment, the one or more control modules may be
further
configured to communicate with other skylight fixtures and drive the sky-
specific
light source and each sun-specific light source such that the sky-specific
emission and sun-specific emission is coordinated with that from the other
skylight fixtures.
[0027a] In one embodiment, a skylight fixture comprises: a sky-resembling
assembly comprising a sky-resembling optical assembly and a sky-specific light
source wherein light from the sky-specific light source exits a planar
interior surface
of the sky-resembling optical assembly as skylight light; a plurality of sun-
resembling assemblies that are arranged adjacent one another and extend
downward from a periphery of the sky-resembling assembly, each of the
plurality of
sun-resembling assemblies comprising a sun-resembling optical assembly and a
sun-specific light source, wherein light from the sun-specific light source
exits a
planar interior surface of the sun-resembling optical assembly as sunlight
light,
wherein the planar interior surfaces of the sky-resembling optical assembly
and the
plurality of sun-resembling optical assemblies define a cavity and an interior
angle
formed between the planar interior surface of the sky-resembling optical
assembly
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6a
and the planar interior surface of each of the sun-resembling optical assembly
is an
obtuse angle; and at least one control module configured to drive the sky-
specific
light source to provide a circadian stimulus and area illuminance at a user-
controlled intensity level.
[0027b] In one embodiment, a skylight fixture comprises: a sky-resembling
assembly comprising a sky-resembling optical assembly and a sky-specific light
source wherein light from the sky-specific light source exits a planar
interior surface
of the sky-resembling optical assembly as skylight light; a plurality of sun-
resembling assemblies that are arranged adjacent one another and extend
downward from a periphery of the sky-resembling assembly, each of the
plurality of
sun-resembling assemblies comprising a sun-resembling optical assembly and a
sun-specific light source wherein light from the sun-specific light source
exits a
planar interior surface of the sun-resembling optical assembly as sunlight
light,
wherein the planar interior surfaces of the sky-resembling optical assembly
and the
plurality of sun-resembling optical assemblies define a cavity; and at least
one
control module configured to, in a first mode, provide area illuminance at a
user-
controlled intensity level by driving the sky-specific light source and each
sun-
specific light source such that the skylight light has a first color point and
the
sunlight light of at least one of the plurality of sun-resembling assemblies
has a
second color point that is different from the first color point, wherein one
of the sky-
specific light source and the sun-specific light source comprises first LEDs
that emit
light having a third color point, second LEDs that emit light having a fourth
color
point, and third LEDs that emit light having a fifth color point.
[0028] While the above features of various embodiments are listed
separately
for clarity, each of the features above may be implemented together in any
combination as long as functionality is not destroyed.
[0029] Those skilled in the art will appreciate the scope of the
present
disclosure and realize additional aspects thereof after reading the following
detailed description of the preferred embodiments in association with the
accompanying drawing figures.
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Brief Description of the Drawing Figures
[0030] The accompanying drawing figures incorporated in and forming a
part
of this specification illustrate several aspects of the disclosure, and
together with
the description serve to explain the principles of the disclosure.
[0031] Figure 1 illustrates a skylight fixture mounted in a ceiling
according to
one embodiment.
[0032] Figure 2A is a cross-section of a skylight fixture according to a
first
embodiment.
[0033] Figure 2B as a cross-section of a skylight fixture according to a
second
embodiment.
[0034] Figure 3 illustrates multiple skylight fixtures mounted in a
ceiling in a
room.
[0035] Figure 4 illustrates a display, which can be used as either a sky-
resembling assembly or a sun-resembling assembly of a skylight fixture.
[0036] Figure 5 illustrates a first light engine embodiment, which can be
used
as either a sky-resembling assembly or a sun-resembling assembly of a skylight
fixture.
[0037] Figure 6 illustrates a second light engine embodiment, which can
be
used as either a sky-resembling assembly or a sun-resembling assembly of a
skylight fixture.
[0038] Figure 7 illustrates a third light engine embodiment, which can be
used
as either a sky-resembling assembly or a sun-resembling assembly of a skylight
fixture.
[0039] Figure 8 is a partial cross-section of a skylight fixture
according to a
third embodiment.
[0040] Figured 9 illustrate multiple skylight fixtures arranged in an
array in a
ceiling.
[0041] Figure 10A is a 1931 CIE Chromaticity Diagram on which a color
space for a first embodiment of a sky-resembling assembly is provided.
[0042] Figure 10B is a table of coordinates that define the color space
illustrated in Figure 10A.
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[0043] Figure 11A is a 1931 CIE Chromaticity Diagram on which a color
space for a first embodiment of a sun-resembling assembly is provided.
[0044] Figure 11B is a table of coordinates that define the color space
illustrated in Figure 11A.
[0045] Figure 12A is a 1931 CIE Chromaticity Diagram on which a color
space for a second embodiment of a sky-resembling assembly is provided.
[0046] Figure 12B is a table of coordinates that define the color space
illustrated in Figure 12A.
[0047] Figure 13A is a 1931 CIE Chromaticity Diagram on which a color
space for a second embodiment of a sun-resembling assembly is provided.
[0048] Figure 13B is a table of coordinates that define the color space
illustrated in Figure 13A.
[0049] Figure 14A is a 1931 CIE Chromaticity Diagram on which a color
space for a third embodiment of a sky-resembling assembly is provided.
[0050] Figure 14B is a table of coordinates that define the color space
illustrated in Figure 14A.
[0051] Figure 15A is a 1931 CIE Chromaticity Diagram on which a color
space for a third embodiment of a sun-resembling assembly is provided.
[0052] Figure 15B is a table of coordinates that define the color space
illustrated in Figure 15A.
[0053] Figure 16A is a 1931 CIE Chromaticity Diagram on which a color
space for a fourth embodiment of both sky-resembling and sun-resembling
assembly is provided.
[0054] Figure 16B is a table of coordinates that define the color space
illustrated in Figure 16A.
[0055] Figure 17 is a 1931 CIE Chromaticity Diagram on which a color
gamut
for a sky-resembling assembly that employs two different colors of LEDs is
provided according to a first embodiment.
[0056] Figure 18 is a graph of the emission spectrum for a bluish LED
for the
embodiment of Figure 17.
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[0057] Figure 19 is a graph of the emission spectrum for a white LED for
the
embodiment of Figure 17.
[0058] Figure 20 is a 1931 CIE Chromaticity Diagram on which a color
gamut
for a sky-resembling assembly that employs three different colors of LEDs is
provided according to a second embodiment.
[0059] Figure 21 is a graph of the emission spectrum for a bluish LED
for the
embodiment of Figure 20.
[0060] Figure 22 is a graph of the emission spectrum for a greenish LED
for
the embodiment of Figure 20.
[0061] Figure 23 is a graph of the emission spectrum for a white LED for
the
embodiment of Figure 20.
[0062] Figure 24 is a 1931 CIE Chromaticity Diagram on which a color
gamut
for a sun-resembling assembly that employs three different colors of LEDs is
provided according to a one embodiment.
[0063] Figure 25 is a cross-section of a skylight fixture according to a
first
embodiment and illustrates the various lighting components of the skylight
fixture.
[0064] Figure 26 as a cross-section of a skylight fixture according to a
second
embodiment and illustrates the various lighting components of the skylight
fixture.
[0065] Figure 27 is a graph of CRI and R9 versus distance from center
nadir
for an exemplary skylight fixture with sky- and sun-resembling assemblies that
employ two different colors of LEDs.
[0066] Figure 28 is a graph of CRI and R9 versus distance from center
nadir
for an exemplary skylight fixture with sky- and sun-resembling assemblies that
employ three different colors of LEDs.
[0067] Figure 29 is a cross-section of a skylight fixture according to a
first
embodiment and illustrates redirection of light emitted from the sun-
resembling
assemblies toward an exit pane of the skylight fixture.
[0068] Figure 30 as a cross-section of a skylight fixture according to a
second
embodiment and illustrates redirection of light emitted from the sun-
resembling
assemblies toward an exit pane of the skylight fixture.
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[0069] Figure 31 is a block diagram of a skylight fixture in
communication with
a remote device according to one embodiment of the disclosure.
[0070] Figure 32 is a schematic diagram of an exemplary electronics
module
and associated sky- and sun-resembling assemblies according to one
5 embodiment.
Detailed Description
[0071] The embodiments set forth below represent the necessary
information
to enable those skilled in the art to practice the embodiments and illustrate
the
10 best mode of practicing the embodiments. Upon reading the following
description
in light of the accompanying drawing figures, those skilled in the art will
understand the concepts of the disclosure and will recognize applications of
these concepts not particularly addressed herein. It should be understood that
these concepts and applications fall within the scope of the disclosure and
the
accompanying claims.
[0072] It will be understood that, although the terms first, second,
etc. may be
used herein to describe various elements, these elements should not be limited
by these terms. These terms are only used to distinguish one element from
another. For example, a first element could be termed a second element, and,
similarly, a second element could be termed a first element, without departing
from the scope of the present disclosure. As used herein, the term "and/or"
includes any and all combinations of one or more of the associated listed
items.
[0073] It will be understood that when an element such as a layer,
region, or
substrate is referred to as being "on" or extending "onto" another element, it
can
be directly on or extend directly onto the other element or intervening
elements
may also be present. In contrast, when an element is referred to as being
"directly on" or extending "directly onto" another element, there are no
intervening elements present. Likewise, it will be understood that when an
element such as a layer, region, or substrate is referred to as being "over"
or
extending "over" another element, it can be directly over or extend directly
over
the other element or intervening elements may also be present. In contrast,
when
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an element is referred to as being "directly over or extending "directly over"
another element, there are no intervening elements present. It will also be
understood that when an element is referred to as being "connected" or
"coupled" to another element, it can be directly connected or coupled to the
other
element or intervening elements may be present. In contrast, when an element
is
referred to as being "directly connected" or "directly coupled" to another
element,
there are no intervening elements present.
[0074] Relative terms such as "below" or "above" or "upper" or "lower"
or
"horizontal" or "vertical" may be used herein to describe a relationship of
one
element, layer, or region to another element, layer, or region as illustrated
in the
Figures. It will be understood that these terms and those discussed above are
intended to encompass different orientations of the device in addition to the
orientation depicted in the Figures.
[0075] The terminology used herein is for the purpose of describing
particular
embodiments only and is not intended to be limiting of the disclosure. As used
herein, the singular forms "a," "an," and "the" are intended to include the
plural
forms as well, unless the context clearly indicates otherwise. It will be
further
understood that the terms "comprises," "comprising," "includes," and/or
"including" when used herein specify the presence of stated features,
integers,
steps, operations, elements, and/or components, but do not preclude the
presence or addition of one or more other features, integers, steps,
operations,
elements, components, and/or groups thereof.
[0076] Unless otherwise defined, all terms (including technical and
scientific
terms) used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this disclosure belongs. It will be further
understood that terms used herein should be interpreted as having a meaning
that is consistent with their meaning in the context of this specification and
the
relevant art and will not be interpreted in an idealized or overly formal
sense
unless expressly so defined herein.
[0077] Disclosed is a lighting fixture that appears as a skylight and is
referred
to as a skylight fixture. The skylight fixture has a sky-resembling assembly
and a
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plurality of sun-resembling assemblies. The sky-resembling assembly has a sky-
resembling optical assembly and a sky-specific light source, wherein light
from
the sky-specific light source exits a planar interior surface of the skylight
optical
assembly as skylight light. The plurality of sun-resembling assemblies are
arranged adjacent one another and extend downward from a periphery of the
sky-resembling assembly. Each of the plurality of sun-resembling assemblies
has
a sun-resembling optical assembly and a sun-specific light source, wherein
light
from the sun-specific light source exits a planar interior surface of the
sunlight
optical assembly as sunlight light. The planar interior surfaces of the
skylight
optical assembly and the plurality of sunlight optical assemblies define a
cavity. It
is understood that the planar surfaces of the various optical assemblies could
have other shapes like curved or circular, such as in a dome shaped lighting
fixture or the like. One or more control modules alone or in a collective are
configured to, in a first mode, drive the sky-specific light source and each
sun-
specific light source such that the sky-specific light emission has a first
color
point and the sun-specific light emission of at least one of the plurality of
sun-
resembling assemblies has a second color point that is different from the
first
color point. The sky-resembling assembly may be configured to emulate a
window of a traditional skylight. Each of the plurality of sun-resembling
assemblies may be configured to emulate sunlight passing through and/or
reflecting off of sidewalls of a traditional skylight.
[0078] An exemplary skylight fixture 10 is illustrated in Figure 1. The
skylight
fixture 10 is mounted in a ceiling structure 12, which in the illustrated
embodiment is a drop ceiling, such as that used in many commercial buildings.
However, those skilled in the art will recognize that the skylight fixture 10
may be
installed in any type of ceiling structure 12, such as drywall, wood, masonry,
and
the like. In essence, the skylight fixture 10 has the general appearance of
and
emulates a traditional skylight. The skylight fixture 10 takes the general
shape of
an inverted box that has multiple sidewalls and a bottom wall. For purposes
that
will become clearer below, the bottom wall is referred to as a sky-resembling
assembly 14, and the sidewalls are referred to as sun-resembling assemblies
16.
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The sky-resembling and sun-resembling assemblies 14, 16 are formed from light
engines, the details of which are described further below.
[0079] In general, the sky-resembling assembly 14 is configured to emit
light
and provide the appearance of the sky to a viewer. In essence, the sky-
resembling assembly 14 emulates the window portion of a traditional skylight.
The sun-resembling assemblies 16 are configured to emulate the sidewalls of a
traditional skylight. Generally, the sidewalls of a traditional skylight
reflect the
more directional sunlight emanating from the sun. For the concepts described
herein, the sun-resembling assemblies 16 are configured to emulate sunlight
coming through the skylight directly at a particular angle or being reflected
off of
a sidewall. Accordingly, the sky-resembling assembly 14 is configured to
provide
the generally non-directional light associated with the sky, whereas the sun-
resembling assembly 16 emulates the direct sunlight or a reflection thereof
from
the sun. Depending on the time of day or night, the intensity, color
temperature,
color of light emitted from the sky-resembling and sun-resembling assemblies
14,
16 will vary in an effort to emulate the light provided by a traditional
skylight at
different times of the day or night and any transitions therebetween.
[0080] Figures 2A and 2B provide cross-sectional views of two different
embodiments of the skylight fixture 10. In the embodiment of Figure 2A, the
sun-
resembling assemblies 16 are essentially orthogonal to the sky-resembling
assembly 14. Opposing sun-resembling assemblies 16 are effectively parallel
with one another. In other words, the exposed surfaces of the sun-resembling
assembly 16 form a 90 degree angle with the exposed surface of the sky-
resembling assembly 14.
[0081] For the embodiment of Figure 2B, the exposed surfaces of the sun-
resembling assembly 16 form an obtuse angle a with the exposed surface of the
sky-resembling assembly 14. As described further below, increasing the angle
between the exposed surfaces of the sun-resembling assemblies 16 and the sky-
resembling assembly 14 may improve emulation of sunlight passing through the
skylight fixture 10. While there is no specific limitation on the value of the
obtuse
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angle a, experiments have shown particularly effective performance when the
obtuse angle a is:
90 degrees <a 135;
95 degrees a 130; or
100 degrees:5. a 125.
[0082] Also illustrated in Figures 2A and 2B are an electronics module 18
and
a general housing 20. The electronics module 18 provides the requisite
electronics for the skylight fixture 10. The electronics module 18 may include
power supply electronics, control electronics, communication electronics,
and/or
the requisite driver circuitry for the sky-resembling and sun-resembling
assemblies 14, 16. In Figures 2A and 2B and select figures to follow, dashed
line
arrows represent the "sunlight" emanating from the sky-resembling assembly 14,
and the solid line arrows represent the "sunlight" emanating directly from or
being
reflected from the sunlight assembly 16.
[0083] Figure 3 illustrates two skylight fixtures 10 mounted in a ceiling
structure 12 in a room with walls 22. While light may not be completely
controlled, Figure 3 illustrates "sunlight" from the sky-resembling assembly
14
projecting predominantly downward into the room, wherein the "sunlight" (solid
line arrows) from the sun-resembling assemblies 16 is projected into the room
in
a more angular fashion, such that the light emanated from the sun-resembling
assemblies 16 illuminates and reflects off of the walls 22 in an effort to
emulate
sunlight coming through a traditional skylight at an angle and directly
lighting up
the walls 22 or being reflected off of a sidewall of a traditional lighting
fixture and
being reflected into the room at an angle.
[0084] As indicated above, both the sky-resembling and sun-resembling
assemblies 14, 16 may be provided by various types of light engines. The sky-
resembling and sun-resembling assemblies 14, 16 in a particular skylight
fixture
10 may incorporate the same or different types of light engines. If the same
light
engines are used for both the sky-resembling and sun-resembling assemblies
14, 16, these light engines may be configured the same or differently
depending
on the spectral capabilities of the light engines.
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[0085] Figures 4-7 illustrate four different types of light engines. The
illustrated
light engines are provided merely as examples, and do not represent an
exclusive or exhaustive list. With reference to Figure 4, the first type of
illustrated
light engine may take the form of a display device, such as a light emitting
diode
5 (LED) display, a liquid crystal display (LCD), an organic LED (OLED)
display, or
the like. A typical display assembly 24 will include a display panel 26 on
which
images are displayed, and appropriate driver electronics 28 to drive the
display
panel 26. Based on the input of the driver electronics 28, the display panel
26 will
display images in the desired manner.
10 [0086] The display assembly 24 is particularly beneficial as a sky-
resembling
assembly 14 due to the tremendous flexibility in scenes that can be displayed
in
an effort to emulate the appearance of the sky during any time of the day or
night. The display can simply provide a uniform color across the display to
emulate the blue sky of day, the sunset in the evening, or the black at night.
In
15 more sophisticated embodiments, the display can vary to indicate clouds,
stars
scattered in the night sky, the reddish orange light illuminating clouds
during a
sunrise or sunset, and the like. In essence, incorporation of a display
assembly
24 provides the flexibility of presenting anything from a specifically colored
panel
to specific still or moving images, which may be coordinated among multiple
skylight fixtures 10.
[0087] The embodiments of Figures 5, 6, and 7 will generally not be
capable
of displaying particular images, but may project light of a varying intensity,
color,
and color temperature while appearing a particular color and brightness.
Notably,
the light emanating from one of these light engines may be different from a
color
of the panel the light engine actually appears. For example, one may want the
light engine to appear blue, but project white light. In these embodiments,
the
light projected from the light engines and the appearance of the light engines
will
be substantially uniform.
[0088] With particular reference to Figure 5, an edge lit-type light
engine is
provided, wherein an optical assembly 32 is edge lit with one or more light
sources 34. In particular, the optical assembly 32 may be a single or multi-
layer
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optical waveguide, diffuser, lens, or any combination thereof. The light
sources
34, which are illustrated as LEDs but are not limited thereto, illuminate the
edges
of the optical assembly 32, and light is emitted from a front surface of the
optical
assembly 32. Typically, the light source 34 will extend along all of at least
one
side of the optical assembly 32, if not multiple or all sides of the optical
assembly
32. The light engine 30 will include a light engine housing 36 to maintain the
optical assembly 32 and the light source 34 in a proper orientation with
respect to
one another, as well as to allow the overall light engine 30 to be mounted in
the
skylight fixture 10. Notably, the LEDs of the light source 34 may be the same
or
different colors, depending on the application. If LEDs of different colors
are
provided, the optical assembly 32 will facilitate the mixing of light from the
various
LEDs, such that light emanates from the front surface of the optical assembly
32
in a uniform manner.
[0089] Turning
now to Figure 6, a back lit-type light engine 40 is illustrated. An
optical assembly 42 that has a front side and an opposing back side is
provided.
A light source 44, such as an array of LEDs, is positioned to illuminate the
back
surface of the optical assembly 42, such that light emitting from the light
source
44 passes through the optical assembly 42 and emanates from the front surface
of the optical assembly 42. Typically, the LEDs of the LED array of the light
source 44 are spaced apart from the back surface of the optical assembly 42,
wherein a mixing chamber 46 is provided between the light source and the back
surface of the optical assembly 42. This allows LEDs of different colors of
light to
be used in the light source 44. The different colors of light will mix in the
mixing
chamber and be passed through the optical assembly 42, which may provide
further mixing and diffusion, depending on the particular application. As with
the
above embodiments, a light engine housing 48 may be provided to hold the
optical assembly 42 and the light source 44 in a proper orientation to one
another
and allow mounting to the skylight fixture 10.
[0090] Figure
7 illustrates a side lit-type light engine 50, which is configured in
a similar fashion to that of Figure 6. The exception is that the LEDs of the
light
source 54 are provided on the sides of the mixing chamber 56 and perpendicular
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to the rear surface of the optical assembly 52. Light from the LEDs from the
light
source 54 will emanate into the mixing chamber 56, and ultimately through the
optical assembly 52 such that mixed light emanates from the front surface of
the
optical assembly 52. A light engine housing 58 may be provided to maintain the
proper orientation of the optical assembly 52 and the light source 54, as well
as
provide the mixing chamber 56. Again, the LEDs of the light source 54 may
provide different colors of light, wherein the mixing chamber 56 and the
optical
assembly 52 are configured such that light emanating from the front surface of
the optical assembly 52 is of a desired color. The light sources 34, 44, and
54
need not be LEDs; however, LED-based light sources provide energy efficient
and high quality light, as will be described further below. The optical
assemblies
32, 42, and 52 may comprise one or more light/waveguides, diffusion films,
lens
films, diffusers, lenses, and the like.
[0091] Figure 8 illustrates a partial cross-section of a skylight
fixture 10,
wherein each of the sun-resembling assemblies 16 employs back lit light
engines
40. Further, the optical assembly 42 is angled such that the exposed surface
of
the optical assembly 42 forms an obtuse angle with the exposed surface of the
sky-resembling assembly 14, which may employ a display assembly 24, light
engine 30, light engine 40, or light engine 50, as described above. As
illustrated,
the light source 44 is an array of LEDs, wherein each LED of the array of LEDs
is
distributed along a vertical surface, which is orthogonal to the exposed
surface of
the sky-resembling assembly 14. A mixing chamber is provided between the LED
array and the back surface of the optical assembly 42. While the LEDs of the
LED array of the light source 44 are arranged on a vertical plane of the light
engine housing 48, the plane on which the LEDs reside may also be angled,
wherein the plane on which the LEDs are arranged is parallel to the optical
assembly 42. In other embodiments, the plane on which the LEDs reside is not
vertical, yet need not be parallel with the optical assembly 42.
[0092] In one embodiment, the appearance of the exposed surfaces of the
sky-resembling and sun-resembling assemblies 14, 16 are configured to appear
as a traditional skylight, which typically has painted, vertical side walls
and a
18
window. As such, the sun-resembling assemblies 16 may have optical
assemblies 32, 42, 52, that have low gloss interior surfaces that are flat
white in
color. The interior surfaces are those that are visible once installed. The
low
gloss, flat white interior surfaces provide the appearance of the vertical
side
walls, which are typically painted flat white. The sun-resembling assemblies
16
will be of high efficacy and provide a CRI equal to or greater than 85 or 90
in
addition to providing an R9 equal to or greater than 50. Ultra-uniform color
mixing
and uniform luminance across the interior surfaces of the optical assemblies
32, 42,
52 enhance the emulation effect.
[0093] The interior surfaces of the optical assembly 32, 42, 52 of the
skylight
fixture 10 may be a matt diffuser. For a waveguide embodiment, the optical
assembly 32 will include a highly reflective backing on the back surface,
which is
opposite the interior surface. The sky-resembling assembly 14 should provide a
CRI of or greater than 85 or 90 in addition to being color changeable. In one
embodiment, the color can range from a sky blue to a very high correlated
color
temperature, such as white light within three, five, seven, or ten MacAdams
ellipses of +/- 5% of 5000K or 5500K, depending on the embodiment.
[0094] Figure 9 illustrates an embodiment wherein multiple (six)
skylight
fixtures 10 are installed in a ceiling structure 12 in close proximity to one
another
to form an appealing matrix of virtual skylights. Through appropriate
electronics,
the light and/or images provided/displayed by each of the skylight fixtures 10
may
be the same or coordinated as desired. For example, the movement of the sun,
the
passing of clouds, movement of shadows and the like may transition from one
skylight fixture 10 to another to form a composite display and/or lighting
effect from the overall group of skylight fixtures 10. Such operation may be
tied to
various sensors, information sensors, and the like, such that the light and/or
information displayed by the skylight fixtures 10 corresponds to an associated
outdoor environment. For additional information on coordinating the effects
provided
by the skylight fixtures 10 with outside environments, reference is made
to U.S. provisional patent application Ser. No. 62/628,131, filed February 8,
2018.
Date Recue/Date Received 2022-02-08
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[0095] As noted, each of the sky-resembling assembly 14 and the sun-
resembling assemblies 16 may be configured the same or differently with
respect
to their lighting capabilities and characteristics. While different ones of
the sun-
resembling assemblies 1 6 may be configured differently on a given skylight
fixture 10, they are generally configured the same on a given skylight fixture
10.
Given the different objectives for the respective sky-resembling and sun-
resembling assemblies 14, 16, the sky-resembling and sun-resembling
assemblies 14, 16 may be designed to operate at different intensity levels,
color
spaces, color temperatures, distribution patterns, and the like as well as
provide
light at different efficacy levels or with different color rendering index
values.
Further, the different sky-resembling and sun-resembling assemblies 14, 16 may
be designed and/or controlled such that each panel provides light with
different
characteristics, yet the light from the overall skylight fixture 10 combines
to
provide light with certain characteristics, which are different from that of
either of
the sky-resembling and sun-resembling assemblies 14, 16.
[0096] With certain embodiments, the sun-resembling assemblies 16 are
designed to emulate the directional nature of sunlight passing through a
traditional skylight. The sky-resembling assemblies 14 are designed to emulate
the appearance of the sky and the non-directional nature of sunlight passing
through a traditional skylight. The sky-resembling and sun-resembling
assemblies 14, 16 may be further configured to emulate the appearance of light
passing through or being reflected from window and side walls of the
traditional
skylight. One of the more significant lighting characteristics in achieving
these
goals is the color space, and in particular, the color point at which the
respective
sky-resembling and sun-resembling assemblies 14, 16 operate.
[0097] In certain embodiments, the light exiting the sky-resembling
assembly
1 4 is relatively shifted toward blue in the light spectrum to better emulate
the
appearance of a blue sky. The light exiting the sun-resembling assembly 16 is
relatively shifted toward the red in the light spectrum to better emulate the
appearance of sunlight. In a first embodiment, the light exiting the sky-
resembling
assembly 14 has a color point within a first skylight color space A. As shown
in
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Figure 10A and listed in the table of Figure 10B, the first skylight color
space A is
defined by the following x, y coordinates on the 1931 CIE Chromaticity
Diagram:
(0.37, 0.34), (0.35, 0.38), (0.15, 0.20), and (0.20, 0.14). The light exiting
the sun-
resembling assembly 16 has one or more color points within a first sunlight
color
5 space A. As shown in Figure 11A and listed in the table of Figure 11B,
the first
sunlight color space A is defined by the following x, y coordinates on the
1931
CIE Chromaticity Diagram: (0.29, 0.32), (0.32, 0.29), (0.41, 0.36), (0.48,
0.39),
(0.48, 0.43), (0.40, 0.41), and (0.35, 0.38). Both the sky-resembling assembly
14
and the sun-resembling assemblies 16 may be configured to vary the color
points
10 during operation to emulate and/or track changing conditions of outside
environments throughout the day and night.
[0098] In a second embodiment, the light exiting the sky-resembling
assembly
14 has a color point within a second skylight color space B. As shown in
Figure
12A and listed in the table of Figure 12B, the second skylight color space B
is
15 .. defined by the following x, y coordinates on the 1931 CIE Chromaticity
Diagram:
(0.32, 0.31), (0.30, 0.33), (0.15, 0.17), and (0.17, 0.14). The light exiting
the sun-
resembling assembly 16 has one or more color points within a second sunlight
color space B. As shown in Figure 13A and listed in the table of Figure 13 B ,
the
second sunlight color space B is defined by the following x, y coordinates on
the
20 1931 CIE Chromaticity Diagram: (0.30, 0.34), (0.30, 0.30), (0.39, 0.36),
(0.45,
0.39), (0.47, 0.43), (0.40, 0.41), and (0.35, 0.38). Both the sky-resembling
assembly 14 and the sun-resembling assemblies 16 may be configured to vary
the color points during operation to emulate and/or track changing conditions
of
outside environments throughout the day and night.
[0099] The first and second embodiments defined above provide relatively
limited color spaces for the respective sky-resembling and sun-resembling
assemblies 14, 16 to operate. These embodiments are geared toward emulating
a traditional skylight during predominately daylight hours between, but not
necessarily including, the sunrise and sunset where the sky may appear less
blue and more reddish orange. To expand the functionality of the skylight
fixture
10 to better emulate the appearance of a traditional skylight outside of
daylight
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hours, operation in expanded color spaces is beneficial. For example, the
color
spaces may need to be shifted or expanded to address the deeper blues
associated with dusk, dawn, and nighttime as well as the more reddish orange
and red hues associated with sunrise and sunset. Exemplary enhanced color
spaces for the sky-resembling and sun-resembling assemblies 14, 16 are
provided in a third embodiment.
[00100] In the third embodiment, the light exiting the sky-resembling assembly
14 has a color point within a third skylight color space C. As shown in Figure
14A
and listed in the table of Figure 14B, the third skylight color space C is
defined by
the following x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.39,
0.31), (0.34, 0.40), (0.10, 0.20), and (0.16, 0.06). The light exiting the sun-
resembling assembly 16 has one or more color points within a third sunlight
color
space C. As shown in Figure 15A and listed in the table of Figure 15B, the
third
sunlight color space C is defined by the following x, y coordinates on the
1931
CIE Chromaticity Diagram: (0.28, 0.36), (0.35, 0.26), (0.44, 0.33), (0.62,
0.34),
(0.50, 0.46), (0.43, 0.45), (0.36, 0.43). Both the sky-resembling assembly 14
and
the sun-resembling assemblies 16 may be configured to vary the color points
during operation to emulate and/or track changing conditions of outside
environments throughout the day and night. The highlighted points in the
graphs
are exemplary color points for the respective sky-resembling and sun-
resembling
assemblies 14, 16.
[00101] In a fourth embodiment, the color spaces for both the sky-resembling
and sun-resembling assemblies 14, 16 are greatly expanded and/or the same or
substantially the same. As shown in Figure 16A and listed in the table of
Figure
.. 16 B, the skylight and sunlight color spaces are defined by the following
x, y
coordinates on the 1931 CIE Chromaticity Diagram: (0.10, 0.20), (0.36, 0.43),
(0.43, 0.45), (0.50, 0.46), (0.62, 0.34), (0.44, 0.33), (0.16, 0.06). Both the
sky-
resembling assembly 14 and the sun-resembling assemblies 16 may be
configured to vary the color points during operation to emulate and/or track
changing conditions of outside environments throughout the day and night. The
highlighted points in the graphs are exemplary color points for the respective
sky-
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resembling (square points) and sun-resembling (triangular points) assemblies
14,
16.
[00102] In any of the above or alternative embodiments, the ccx value on the
1931 CIE Chromaticity Diagram of the color point of light exiting the sky-
resembling assembly 14 may be less or about equal than the ccx value on the
1931 CIE Chromaticity Diagram of the color point of light exiting the sun-
resembling assembly 16. Alternatively, the ccy value on the 1931 CIE
Chromaticity Diagram of the color point of light exiting the sky-resembling
assembly 14 can be less or about equal than the ccy value on the 1931 CIE
Chromaticity Diagram of the color point of light exiting the sun-resembling
assembly 16. In other embodiments, both the ccx value on the 1931 CIE
Chromaticity Diagram of the color point of light exiting the sky-resembling
assembly 14 is less than or about equal the ccx value on the 1931 CIE
Chromaticity Diagram of the color point of light exiting the sun-resembling
assembly 16, and the ccy value on the 1931 CIE Chromaticity Diagram of the
color point of light exiting the sky-resembling assembly 14 is less than or
about
equal the ccy value on the 1931 CIE Chromaticity Diagram of the color point of
light exiting the sun-resembling assembly 16.
[00103] In LED-based embodiments, the arrays of LEDs are used for one or
both of the sky-resembling and sun-resembling assemblies 14, 16. In the
following embodiments, assume that LED arrays are used for both the sky-
resembling and sun-resembling assemblies 14, 16. In the first embodiment,
which is described in association with the 1931 CIE Chromaticity Diagram of
Figure 17, a two-color LED array is employed as the light source for the sky-
resembling assembly 14. A two-color LED array will have multiple LEDs of a
first
color and multiple LEDs of a second color.
[00104] For this embodiment, the first LEDs are bluish LEDs that emit bluish
light with a color point CP1 in the lower left of the 1931 CIE Chromaticity
Diagram. The bluish LEDs have a 475 nm dominant wavelength and an overall
spectrum that is illustrated in Figure 18, which is a graph of output
intensity
versus wavelength. The second LEDs are a white LEDs that emit white light at a
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color point CP2 on or within three or five MacAdam Elilipses of the Black Body
Curve. In this example, the white LEDs have a color temperature of
approximately 5000K (+/- 0.5, 1, 2, or 5%) and a color rendering index (CRI)
of at
least 85 or 90 (i.e. CRI 85, CRI 90). The white LEDs have an overall spectrum
that is illustrated in Figure 19, which is a graph of output intensity versus
wavelength.
[00105] For a two-color LED array, the color point of light exiting the sky-
resembling assembly 14 can vary along a tie line that extends between the
color
points associated with the bluish and white LEDs depending on the extent to
which the respective LEDs are driven. In this embodiment, the color point of
the
light exiting the sky-resembling assembly 14 can vary in color along the tie
line
from white light with a color temperature of approximately 5000K to a sky
blue.
Three exemplary color points for sky targets are shown as circles on the tie
line.
While a two-color LED array is cost effective and provides variable color
points
along a defined tie line, the overall spectrum associated with the light
emitted
from a two-color LEDs array is somewhat limited.
[00106] One way to increase the overall spectral gamut of the emitted light
from the sky-resembling assembly 14 is two use three or more LEDs in the LED
array. Using three or more colors in the LED array is beneficial, even if the
design dictates varying color along a single, linear tie line. An example of a
three
color-LED array is illustrated in the 1931 CIE Chromaticity Diagram of Figure
20.
In this example, deeper bluish LEDs, greenish LEDs, and white LEDs are
employed. The deeper bluish LEDs emit bluish light with a color point CP3 in
the
lower left of the 1931 CIE Chromaticity Diagram. The bluish LEDs have a 460 nm
dominant wavelength, but can range from about 450nm to about 465nm in
dominant wavelength as illustrated in Figure 21, which is a graph of output
intensity versus wavelength.
[00107] The greenish LEDs emit greenish light with a color point CP5 in the
upper left of the 1931 CIE Chromaticity Diagram. The greenish LEDs have a 520
nm dominant wavelength but can range from about 505 nm to about 530 nm in
dominant wavelength as illustrated in Figure 22, which is a graph of output
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intensity versus wavelength. The white LEDs emit white light at a color point
CP5
on or within three or five MacAdam Elilipses of the Black Body Curve. In this
example, the white LEDs have a color temperature of approximately 5000K (+/-
0.5, 1, 2, or 5%) and a color rendering index (CRI) of at least 85 or 90 (i.e.
CRI
85, CRI 90). The white LEDs have an overall spectrum that is illustrated in
Figure
23, which is a graph of output intensity versus wavelength. While certain
colors of
LEDs are used in the described embodiments, LEDs of various colors and
combinations thereof are considered within the scope of the disclosure.
[00108] Similar concepts are used to design the sun-resembling assemblies
16. For example, the 1931 CIE Chromaticity Diagram of Figure 24 shows three
exemplary color spaces for each of three colors of LEDs. Color space CS1
resides in the upper left part of the diagram and corresponds to a greenish
yellow
LED that emits greenish yellow light. Color space CS2 resides in the lower
left
part of the diagram and corresponds to a greenish blue LED that emits greenish
blue light. Color space C53 resides in the lower right part of the diagram and
corresponds to a reddish LED that emits reddish blue light. The combination of
these three different colors of LEDs allows great flexibility in controlling
the color
and color temperature of the light exiting the sun-resembling assemblies 16.
In a
more focused application where the sun-resembling assemblies 16 are emulating
solely or primarily sunlight and reflections thereof during sunrise, sunset,
and
daylight times, a target range for the color space resides along the Black
Body
curve and extends from about 5600K to 2700K, inclusive, within three, five,
seven, or ten MacAdams ellipses.
[00109] For reference, color space CS1 is defined by the following x, y
coordinates on the 1931 CIE Chromaticity Diagram: (0.337421, 0.498235),
(0.361389, 0.547099), (0.345207, 0.557853), and (0.320079, 0.506653). Color
space C52 is defined by the following x, y coordinates on the 1931 CIE
Chromaticity Diagram: (0.253872, 0.284229), (0.281968, 0.363411), (0.269385,
0.367235), and (0239191, 0.282521). Color space CS3 is defined by the
following x, y coordinates on the 1931 CIE Chromaticity Diagram: (0.547946,
0.298632), (0.532764, 0.307913), (0.586923, 0.341618), and (0.602105,
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0.332400). Again, these are non-limiting examples that are provided for the
purposes aiding those skilled in the art in understanding the concepts
described
herein.
[00110] With reference to Figures 25 and 26, the skylight fixture 10 provides
5 both vertical and horizontal lighting components. The vertical component
is
provided by the sky-resembling assembly 14, and the horizontal component is
provided by the sun-resembling assemblies 16. Even though the sun-resembling
assemblies 16 are not exactly vertical for the embodiment of Figure 26, for
the
purposes herein, the sun-resembling assemblies 16 are considered to provide a
10 horizontal lighting component. These vertical and horizontal lighting
components
ultimately combine to provide a composite lighting component that exits the
skylight fixture 10 at an exit plane, which is a plane corresponding to the
opening
of the skylight fixture 10 opposite the sky-resembling assembly 14.
[00111] The vertical and horizontal lighting components are independently
15 controllable with respect to one or more of intensity, color, color
temperature,
CRI, and the like. As such, the emission profile associated with the composite
lighting component, which is effectively the output of the overall skylight
fixture
10, can be tailored by controlling the vertical lighting component provided by
the
sky-resembling assembly 14 and the horizontal lighting components provide by
20 the multiple sun-resembling assemblies 16. Notably, the horizontal
lighting
components provided by the different sun-resembling assemblies 16 may be the
same or different to provide both symmetrical and asymmetrical emission
profiles. For example, the skylight fixture 10 may be designed to provide the
functionality described above and still have the composite lighting component
25 provide a desired emission profile with a desired color, color
temperature, CRI, or
any combination thereof. The emission profile of the composite lighting
component may have a normalized intensity distribution (i.e. substantially
Lambertian Emission profile) to one that is substantially ellipsoidal,
symmetrical,
or asymmetrical.
.. [00112] Further, by employing three or more colors of LEDs for either or
both of
the sky-resembling and sun-resembling assemblies 14, 16, the white light color
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quality of the composite light output of the overall skylight fixture 10 can
be
significantly improved. In particular, the CRI of the composite light output
of the
overall skylight fixture 10 can be improved.
[00113] With regard to CAI, an LED-based fixture's CRI is calculated by
measuring its CRI ratings for various individual colors, which are referred to
as
R1 through R8, and then taking an average of the results. Interestingly, R9
(red)
and R13 (skin tone/beige) are generally not taken into consideration when
calculating CRI. These red and skin tone colors have a significant impact on
rendering skin colors in a healthy and natural way as well as making people
feel
at ease and more alert. As such, lighting may have a high CRI and still lack
the
red and skin tone color content necessary to properly render skin tones and/or
enhance mood and alertness. The expanded spectrum provided by using LEDs
of three or more colors for a given one of the sky-resembling and sun-
resembling
assemblies 14, 16 can improve the CRI rating as well as the perceived quality
of
the composite lighting component. The expanded spectrum may also significantly
improve the quality of the vertical and horizontal lighting components.
[00114] Figures 27 and 28 illustrate the improvement in both CRI and R9 of the
composite lighting component when employing LEDs of three or more colors.
Figure 27 is a graph of CRI and R9 over distance from center Nadir (that is
six
feet from the fixture) for the two-color LED embodiment of Figure 17. Center
Nadir in this test is approximately six feet from the center of the exit plane
of the
skylight fixture 10. Figure 28 is a graph of CRI and R9 over distance from
center
Nadir for the three-color LED embodiment of Figure 20. The CRI across the
entire range significantly improved, and the CRI curve flattened, which
indicates
tremendous CRI improvement at lower distances. The R9 also improved on
average.
[00115] Figures 29 and 30 illustrate techniques for improving efficacy
associated with the overall skylight fixture 10, the sun-resembling assemblies
16,
or both. Figure 29 illustrates the benefit of having an angle of greater than
90
degrees between the interior face of the sun-resembling assemblies 16 and the
sky-resembling assembly 14. In essence, the light output distribution of the
sun-
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resembling assemblies 16 favors toward the exit plane, or in other words, is
angled downward toward the exit plane. Angling the light output distribution
of the
sun-resembling assemblies 16 downward reduces the losses associated with the
light being passed through and reflected by the light emitting surfaces of the
other sun-resembling assemblies 16 and the sky-resembling assembly 14. Again,
experiments have shown particularly effective performance when the obtuse
angle a is:
90 degrees <a 135;
95 degrees <a 130; or
100 degrees < a 125.
[00116] Figure 30 illustrates another embodiment wherein the interior surfaces
of the sun-resembling assemblies 16 are substantially vertical, but the
optical
configuration of the sun-resembling assemblies 16 are such that the light
output
distribution of the sun-resembling assemblies 16 is directed or redirected to
favor
toward the exit plane, or in other words, is angled downward toward the exit
plane. This can be provided by angling the plane on which the LED array is
provided, employing a diffusor or waveguide structure to redirect the light
from
the LED array, or the like. Allowing more of the light from the sun-resembling
assemblies 16 to escape the skylight fixture 10 without impediment may also
increase the emulation of sunlight passing through a traditional skylight at
lower
angles and more directly illuminating walls, such as during the morning or
evening as well as during those fall, winter, and spring months of the year
when
the earth remains off axis relative to the sun (i.e. the sun is lower on the
horizon
through the day).
[00117] As described above, the respective sky-resembling and sun-
resembling assemblies 14, 16 can be individually controlled such that light
provided by the sky-resembling and sun-resembling assemblies 14, 16 can emit
light at different color points at any given time. The particular color points
for the
light from the sky-resembling and sun-resembling assemblies 14, 16 may be
permanently fixed or dynamically controlled such that the color points for the
emitted light can change based on user input, a predefined program, or as a
28
function of any number or combination of variables. The variables may range
from
date, day, and time of day to any number of sensor outputs, such as indoor
and/or
outdoor temperature sensors, light sensors, motion sensors, humidity sensors,
rain sensors, and the like.
[00118] The sky-resembling and sun-resembling assemblies 14, 16 may be
further controlled such that the composite lighting output of the skylight
fixture 10
achieves a certain color, color temperature, CRI, and/or the like while
achieving
other lighting goals, such as emulating a traditional skylight in a fixed or
dynamic
manner. While emulating a traditional skylight has been the subject of much of
the discussion thus far, the sky-resembling and sun-resembling assemblies 14,
16 may be controlled to enhance moods, support general and mental health,
and/or provide other physiological benefits.
[00119] For example, the skylight fixture 10 may be configured to deliver an
enhanced circadian stimulus, with reference to Rea, M.S. et al; A model of
phototransduction by the human circadian system; Brain Research Reviews 50
(2005) 213 - 228. This is done by controlling the ratio between the horizontal
and
vertical illuminance provided by the sky-resembling and sun-resembling
assemblies 14, 16. The circadian stimulus is controlled by the spectral power
distribution, the color temperature and the amount of light of the respective
characteristics delivered to the human eye. Vertical illuminance, such as that
provided by the sun-resembling assemblies 16, appears to have the greatest
efficiency in delivering an impact on circadian rhythms. The skylight fixture
10, by
virtue of its vertical and horizontal light emitting surfaces along with
independent
spectral and brightness control, can provide effective control of this
stimulus.
Controlling the sky-resembling and sun-resembling assemblies 14, 16 to provide
a
zonal luminance distribution of 35% or more in a region of 60-90 degrees of
nadir
will provide a higher vertical illuminance. This could be provided by
increasing the
brightness of the sun-resembling assemblies 16 and decreasing or maintaining
the
brightness of the sky-resembling assembly 14. Further, light with a higher
amount
of red spectral
Date Recue/Date Received 2022-02-08
29
content may be emitted from the sun-resembling assemblies 16, further
modulating the circadian or other alertness stimulation, as desired.
[00120] The skylight fixtures 10 may control the characteristics of light
throughout the day based on when and how much circadian stimulus is desired.
In the morning or during a certain time period in the morning, the skylight
fixture
will increase its 60-90 degree illuminance to 35% or more and change the
spectral power distribution and/or system vertical illuminance to provides a
circadian stimulus of > 0.3, which is a preferred circadian entrainment for
humans
according to Rea MS, Figueiro MG, Bierman A, Bullough JD.; J Circadian
10 Rhythms; 2010 Feb 13;8(1):2. Later in the day, the skylight fixture 10
could
reduce its circadian stimulus by providing a spectral power distribution and
system vertical illuminance that results in a circadian stimulus of < 0.1. One
element of this reduction could be a change of the 60-90 degree zonal
illuminance distribution 35% or less by modifying the sky-resembling and sun-
resembling assembly 14, 16 emission (brightness and/or spectral content)
ratios.
[00121] In another embodiment, the red spectral content provided by the sun-
resembling assemblies 16 can be temporarily increased to increase the red
vertical illuminance provided by the skylight fixture 10 during post lunch
hours
and/or at night to counter the so called "post-lunch dip" and/or to improve
nighttime alertness of shift workers. For the potential of increasing the
alertness
of shift workers by exposing them to a vertical illuminance of red light,
reference
is made to Figueiro M. G. et al., Biological Research for Nursing 2016, Vol.
18(1)
90. For the potential of increasing the alertness during the "post-lunch dip"
in
humans by providing increased red light exposure, reference is made to Sahin
L.,
Figueiro M.G.; Physiology & Behavior, Vol.116-117, 2013, 1. Again, all of the
above embodiments may be provided while or without maintaining desired
characteristics of the composite lighting output for the skylight fixture 10.
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[00122] Multiple skylight fixtures 10 may be controlled collectively by a
remote
source, by a master fixture, or in a distributed fashion to operate in concert
to
present a static or dynamic scene. Each of the skylight fixtures 10 may have
different or the same light output of the respective sky-resembling and sun-
5 resembling assemblies 14, 16, depending on the nature of the scene. In
one
scenario, each of the skylight fixtures 10 may provide the same light output
for a
scene, such that each of the skylight fixtures 10 has the same appearance for
a
uniform scene. In another scenario, two or more of the skylight fixtures 10
will
have different light output configurations, wherein each skylight fixture 10
10 represents a portion of an overall scene. The skylight fixtures 10 may
also be
controlled to provide virtually any type of mood, theme, holiday, or like
lighting as
well wherein the color, color temperature, brightness, and spectral content of
the
light emitted from the sky-resembling and sun-resembling assemblies 14, 16 is
only limited by the nature and capabilities of the light sources and the
control
15 thereof. The skylight fixtures 10 may be controlled or configured to
operate in
different modes at different times or in response to sensor input or outside
control
input.
[00123] For example, the skylight fixtures 10 may function to emulate a
traditional skylight with a changing scene that tracks outside conditions
during
20 business hours and transitions to decorative accent lighting mode during
non-
business hours. Alternatively, the skylight fixtures 10 may transition to a
mode
that enhances alertness or provides some other type of circadian stimuli after
normal business hours. Again, such control may be provided by a programming
of the skylight fixture or remote control in isolation or based on various
input from
25 other sensors and the like. The independent control and the potential
for different
capabilities and configurations of the respective sky-resembling and sun-
resembling assemblies 14, 16 provide tremendous flexibility for a skylight-
shaped
lighting fixture.
[00124] Figure 31 shows a block diagram of a skylight fixture 10 that is
capable
30 of providing wired or wireless communications with a remote device 51.
The
remote device 51 may be another lighting fixture or skylight fixture 10, a
remote
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control system provided on a server, personal computer, or the like, as well
as a
mobile computing device, such as a smart phone, commissioning tool, dedicated
control module, and the like. Communications between the electronics module 18
and the remote device 51 may be wired or wireless and may work on any type of
networking technology. The remote device 51 will include a central processing
unit (CPU) 53 or the like, and associated memory 55, which will include the
requisite software for controlling operation of the remote device 51 and
communications with the electronics module 18. The CPU 53 may be associated
with a communication interface 57, which will provide the requisite
communication capability for the remote device 51.
[00125] Figure 32 illustrates an exemplary electronics module 18 in
association
with a sky-resembling assembly 14 and one or more sun-resembling assemblies
16 for a skylight fixture 10. In the illustrated embodiment, the sky-
resembling
assembly 14 is expanded to illustrate an LED array, which includes a mixture
of
LEDs 59 of different colors. While those skilled in the art will recognize
various
color combinations, the following example employs white LEDs 59 that emit
white
light at a first wavelength, bluish LEDs 59 that emit bluish light at a second
wavelength, and greenish LEDs 59 that emit greenish light at a third
wavelength.
The LED array may be divided into multiple strings of series-connected LEDs
59.
In this embodiment, LED string LS1 includes the white LEDs 59 and forms a
first
group of LEDs. LED string LS2 includes the bluish LEDs 59 and forms a second
group of LEDs. LED string LS3 includes the greenish LEDs 59 and forms a third
group of LEDs.
[00126] The electronics module 18 controls the drive currents i1, i2, and i3,
which are used to drive the respective LED strings LS1, LS2, and LS3 of the
sky-
resembling assembly 14. The sun-resembling assemblies 16 may be similarly
configured and driven by the same or different electronics modules 18 in
similar
fashion. The ratio of drive currents i1, i2, and i3 that are provided through
respective LED strings LS1, LS2, and LS3 may be adjusted to effectively
control
the relative intensities of the white light emitted from the white LEDs 59 of
LED
string LS1, the bluish light emitted from the bluish LEDs 59 of LED string
LS2,
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and the greenish light emitted from the green LEDs 59 of LED string LS3. The
resultant light from each LED string LS1, LS2, and LS3 mixes to generate an
overall light output that has a desired color, correlated color temperature
(CCT),
and intensity, the latter of which may also be referred to as dimming level.
As
noted, the overall light output may take on any desired color or COT.
[00127] When emulating a traditional skylight, the overall light output of the
sky-resembling assembly 14 may range from a deep blue of an evening sky, to a
medium blue of a daytime sky, to white light that falls on or within a desired
proximity of the Black Body Locus (BBL) and has a desired OCT. The sun-
resembling assemblies 16 are controlled in the same fashion to emulate direct
and reflected sunlight as well as any of the other colors and CCTs described
above for effects ranging from decorative to physiological.
[00128] The number of LED strings LSx may vary from one to many and
different combinations of LED colors may be used in the different strings.
Each
LED string LSx may have LEDs of the same color, variations of the same color,
or substantially different colors. In the illustrated embodiment, each LED
string
LS1, LS2, and LS3 is configured such that all of the LEDs 59 that are in the
string
are all essentially identical in color. However, the LEDs 59 in each string
may
vary substantially in color or be completely different colors in certain
embodiments. A single string embodiment is also envisioned, wherein currents
may be individually adjusted for the LEDs of the different colors using bypass
circuits or the like.
[00129] The electronics module 18 includes AC-DC conversion circuitry 61,
control circuitry 60, a communication interface (I/F) 62, and a number of
current
sources, such as the illustrated DC-DC converters 64. The AC-DC conversion
circuitry 61 is configured to receive an AC signal (AC), rectify the AC
signal,
correct the power factor of the AC signal, and provide a DC power signal
(PWR).
The DC power signal may be used to directly or indirectly power the control
circuitry 60 and any other circuitry provided in the electronics module 18,
including the DC-DC converters 64 and the communication interface 62.
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[00130] The three respective DC-DC converters 64 of the electronics module
18 provide drive currents i1, i2, and i3 for the three LED strings LS1, LS2,
and LS3
of the sky-resembling assembly 14 in response to control signals CS1, CS2, and
CS3. As noted, additional drive circuitry may be provided for each of the sun-
resembling assemblies 16 in similar fashion. The drive currents i1, i2, and i3
may
be pulse width modulated (PWM) signals or variable DC signals. If the drive
currents i1, i2, and i3 are PWM signals, the control signals CS1, CS2, and CS3
may be PWM signals that effectively turn the respective DC-DC converters 64 on
during a logic high state and off during a logic low state of each period of
the
PWM signal. As a result, the drive currents i1, i2, and i3 for the three LED
strings
LS1, LS2, and LS3 may also be PWM signals. The intensity of light emitted from
each of the three LED strings LS1, LS2, and LS3 will vary based on the duty
cycle of the respective PWM signals.
[00131] The control circuitry 60 will adjust the duty cycle of the drive
currents
i2, and i3 provided to each of the LED strings LS1, LS2, and LS3 to
effectively
adjust the intensity of the resultant light emitted from the LED strings LS1,
LS2,
and LS3 while maintaining the desired intensity, color and/or CCT based on
instructions from the control circuitry 60. If the drive currents i1, i2, and
i3 for the
three LED strings LS1, LS2, and LS3 are variable DC currents, the control
circuitry 60 generates control signals CS1, CS2, and CS3 that result in the DC-
DC converters 64 outputting the drive currents 11, i2, and i3 at the
appropriate DC
levels.
[00132] The control circuitry 60 may include a central processing unit (CPU)
66, such as microprocessor or microcontroller, and sufficient memory 68 to
store
the requisite data and software instructions to enable the control circuitry
60 to
function as described herein. The control circuitry 60 may interact with the
communication interface 62 to facilitate wired or wireless communications with
other skylight fixtures 10 or remote devices, as described above.
[00133] When the terms "control system" or "control circuitry" are used in the
claims or generically in the specification, the term should be construed
broadly to
include the hardware and any additional software or firmware that is needed to
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provide the stated functionality. These terms should not be construed as only
software, as electronics are needed to implement control systems described
herein. For example, a control system may, but does not necessarily, include
the
control circuitry 60, the DC-DC converters 64, the AC-DC conversion circuitry
58,
and the like.
[00134] The expression "correlated color temperature" ("CCT") is used
according to its well-known meaning to refer to the temperature of a blackbody
that is nearest in color, in a well-defined sense (i.e., can be readily and
precisely
determined by those skilled in the art). Persons of skill in the art are
familiar with
.. correlated color temperatures, and with Chromaticity diagrams that show
color
points to correspond to specific correlated color temperatures and areas on
the
diagrams that correspond to specific ranges of correlated color temperatures.
Light can be referred to as having a correlated color temperature even if the
color
point of the light is on the blackbody locus (i.e., its correlated color
temperature
would be equal to its color temperature); that is, reference herein to light
as
having a correlated color temperature does not exclude light having a color
point
on the blackbody locus.
[00135] "Light engine" or "light source" can be any structure (or combination
of
structures) from which light exits. In many cases, a light engine consists of
one or
more light sources plus one or more mechanical elements, one or more optical
elements and/or one or more electrical elements. In many cases, a light engine
is
a component of a light fixture, i.e., it is not a complete light fixture, but
it can be a
discrete group or set of LEDs that is spatially segregated and controlled as a
unit.
In some embodiments, for instance, a light engine in a light fixture can be a
discrete set of LEDs (e.g., an array of LEDs) mounted to a board (e.g., a
printed
circuit board) that is separate from one or more other light engines in the
light
fixture. In some embodiments, a larger board can comprise different sets or
groups of LEDs occupying different portions of the board, and thereby comprise
multiple light engines. A light engine can, for example, comprise chip-on-
board,
packaged LEDs, secondary optics and/or control/drive circuitry. In some
embodiments, a light fixture can comprise a first light engine comprising
multiple
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LEDs on a first board, and a second light engine comprising multiple LEDs on a
second board. In some embodiments, a light engine can comprise multiple LEDs
spaced from each other (in the aggregate) in one dimension, in two dimensions
or in three dimensions.
5 [00136] For example, a first light engine can be mounted adjacent to or
spaced
laterally from but on the same plane with a second light engine and thereby
spaced in one dimension. A first light engine can be positioned adjacent to or
spaced from a second light engine but positioned at an angle or on a second
plane from the second light engine and thereby in two dimensions. A first
light
10 engine can be offset from a second light engine in two or three
dimensions. A
first light engine can be offset or positioned relative to two, three or more
dimensions of one or more other light engines. In some embodiments, a light
engine can comprise a single light source (e.g., a single LED), or an array of
light
sources (e.g., a plurality of LEDs, a plurality of other light sources, or a
15 .. combination of one or more LEDs and/or one or more other light sources).
In
some embodiments, a plurality of light sources (e.g., a plurality of LEDs) can
be
on a board and controlled together, for example, a control device (that
controls
the color point of a mixture of light from the plurality of light sources,
and/or that
controls brightness of light emitted from one or more of the plurality of
light
20 sources, etc.) can control a plurality of light sources on a board
(and/or can
control all of the light sources on a board).
[00137] The expression "light exit region," "light exit surface," or "exit
plane"
(e.g., "at least a first light exit region is at a boundary of the space"),
means any
region through which light passes (e.g., as it travels from a space which is
to one
25 side of the light exit region to the other side of the light exit
region, i.e., as it exits
the space through the light exit region). For example, if a light fixture has
a
cylindrical surface that defines an internal space (closed at the top and open
at
the bottom), light can exit the space by traveling through the circular light
exit
region at the bottom of the cylindrical surface (i.e., such circular light
exit region
30 is defined by the lower edge of the cylindrical surface). Such a light
exit region
can be open, or it can be partially or completely occupied by a structure that
is at
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least partially light-transmitting (e.g., transparent or translucent). For
example, a
light exit region can be an opening in an opaque structure (through which
light
can exit), a light exit region can be a transparent region in an otherwise
opaque
structure, a light exit region can be an opening in an opaque structure that
is
.. covered by a lens or a diffuser, etc.
[00138] Unless otherwise defined, all terms (including technical and
scientific
terms) used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this inventive subject matter belongs. It
will be
further understood that terms, such as those defined in commonly used
dictionaries, should be interpreted as having a meaning that is consistent
with
their meaning in the context of the relevant art and the present disclosure
and will
not be interpreted in an idealized or overly formal sense unless expressly so
defined herein. It will also be appreciated by those of skill in the art that
references to a structure or feature that is disposed "adjacent" another
feature
may have portions that overlap or underlie the adjacent feature.
[00139] The color of visible light emitted by a light source, and/or the color
of a
mixture visible light emitted by a plurality of light sources can be
represented on
either the 1931 CIE (Commission International de l'Eclairage) Chromaticity
Diagram or the 1976 CIE Chromaticity Diagram. Persons of skill in the art are
.. familiar with these diagrams, and these diagrams are readily available.
[00140] The CIE Chromaticity Diagrams map out the human color perception in
terms of two CIE parameters, namely, x (or ccx) and y (or ccy) (in the case of
the
1931 diagram) or u' and v' (in the case of the 1976 diagram). Each color point
on
the respective diagrams corresponds to a particular hue. For a technical
description of CIE chromaticity diagrams, see, for example, "Encyclopedia of
Physical Science and Technology", vol. 7, 230-231 (Robert A Meyers ed., 1987).
The spectral colors are distributed around the boundary of the outlined space,
which includes all of the hues perceived by the human eye. The boundary
represents maximum saturation for the spectral colors.
[00141] The 1931 CIE Chromaticity Diagram can be used to define colors as
weighted sums of different hues. The 1976 CIE Chromaticity Diagram is similar
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to the 1931 Diagram, except that similar distances on the 1976 Diagram
represent similar perceived differences in color.
[00142] The expression "hue", as used herein, means light that has a color
shade and saturation that correspond to a specific point on a CIE Chromaticity
Diagram, i.e., a color point that can be characterized with x, y coordinates
on the
1931 CIE Chromaticity Diagram or with u', v' coordinates on the 1976 CIE
Chromaticity Diagram.
[00143] In the 1931 CIE Chromaticity Diagram, deviation from a color point on
the diagram can be expressed either in terms of the x, y coordinates or,
alternatively, in order to give an indication as to the extent of the
perceived
difference in color, in terms of MacAdam ellipses (or plural-step MacAdam
ellipses). For example, a locus of color points defined as being ten MacAdam
ellipses (also known as "a ten-step MacAdam ellipse) from a specified hue
defined by a particular set of coordinates on the 1931 CIE Chromaticity
Diagram
consists of hues that would each be perceived as differing from the specified
hue
to a common extent (and likewise for loci of points defined as being spaced
from
a particular hue by other quantities of MacAdam ellipses).
[00144] A typical human eye is able to differentiate between hues that are
spaced from each other by more than seven MacAdam ellipses (and is not able
to differentiate between hues that are spaced from each other by seven or
fewer
MacAdam ellipses).
[00145] Since similar distances on the 1976 Diagram represent similar
perceived differences in color, deviation from a point on the 1976 Diagram can
be expressed in terms of the coordinates, u' and v', e.g., distance from the
point
= (Au'2 + Av'2)1/2. This formula gives a value, in the scale of the u' v'
coordinates,
corresponding to the distance between points. The hues defined by a locus of
points that are each a common distance from a specified color point consist of
hues that would each be perceived as differing from the specified hue to a
common extent.
[00146] A series of points that is commonly represented on the CIE Diagrams
is referred to as the blackbody locus. The chromaticity coordinates (i.e.,
color
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points) that lie along the blackbody locus correspond to spectral power
distributions that obey Planck's equation: E(A)=A A-5003/TH), where E is the
emission intensity, A is the emission wavelength, T is the temperature of the
blackbody and A and B are constants. The 1976 CIE Diagram includes
temperature listings along the blackbody locus. These temperature listings
show
the color path of a blackbody radiator that is caused to increase to such
temperatures. As a heated object becomes incandescent, it first glows reddish,
then yellowish, then white, and finally bluish. This occurs because the
wavelength associated with the peak radiation of the blackbody radiator
becomes
.. progressively shorter with increased temperature, consistent with the Wien
Displacement Law. Illuminants that produce light that is on or near the
blackbody
locus can thus be described in terms of their color temperature.
[00147] The expression "dominant wavelength" is used herein according to its
well-known and accepted meaning to refer to the perceived color of a spectrum,
i.e., the single wavelength of light which produces a color sensation most
similar
to the color sensation perceived from viewing light emitted by the light
source, as
opposed to "peak wavelength", which is well known to refer to the spectral
line
with the greatest power in the spectral power distribution of the light
source.
Because the human eye does not perceive all wavelengths equally (it perceives
yellow and green better than red and blue), and because the light emitted by
many solid state light emitters (e.g., light emitting diodes) is actually a
range of
wavelengths, the color perceived (i.e., the dominant wavelength) is not
necessarily equal to (and often differs from) the wavelength with the highest
power (peak wavelength). A truly monochromatic light such as a laser has a
dominant wavelength that is the same as its peak wavelength.
[00148] It is well known that light sources that emit light of respective
differing
hues (two or more) can be combined to generate mixtures of light that have
desired hues (e.g., non-white light corresponding to desired color points or
white
light of desired color temperature, etc.). It is also well known that the
color point
produced by mixtures of colors can readily be predicted and/or designed using
simple geometry on a CIE Chromaticity Diagram. It is further well known that
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starting with the notion of a desired mixed light color point, persons of
skill in the
art can readily select light sources of different hues that will, when mixed,
provide
the desired mixed light color point.
[00149] For example, persons of skill in the art can select a first light
engine
(e.g., comprising a light emitting diode and phosphor), plot the color point
of the
light exiting from the first light engine (i.e., a first color point) on a CIE
Chromaticity Diagram, plot a desired range of color points (or a single
desired
color point) for mixed light, and draw one or more line segments through the
desired range of color points (or the single color point) for the mixed light
such
that the line segment(s) extend beyond the desired color point(s). Each line
segment drawn in this way will have one end at the first color point, will
pass
through the range for the desired mixed light color point (or the desired
single
color point), and will have its other end at a second color point.
[00150] A second light engine can be provided from which light of the second
color point exits, and when the first light engine and the second light engine
are
energized so that light exits from them, the color point of the mixed light
will
necessarily lie along a line segment connecting the first color point and the
second color point, and the location of the color point of the mixed light
along the
line segment will be dictated by (namely, proportional to) the relative
brightness
of the respective light that exits from the first and second light engines.
That is,
the greater the proportion of the mixed light that is from the second light
engine,
the closer the color point of the mixed light is to the second color point;
this
relationship is geometrically proportional, i.e., the fraction of the length
of the line
segment that the color point of the mixed light is spaced from the first color
point
is equal to the fraction of the mixed light that is from the second light
engine (and
vice-versa). In geometric terms, the ratio of (1) the distance from the first
color
point to the color point of the mixed light, divided by (2) the distance from
the first
color point to the second color point will be equal to the ratio of the
brightness (in
lumens) of the first light engine divided by the brightness (in lumens) of the
combination of light in the mixed light. Accordingly, once one identifies
light
sources (or light engines) that provide the endpoints of a line segment that
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extends through the desired mixed light color point, the desired mixed light
color
point can be obtained by calculating the relative brightness of the first and
second light sources (or light engines) necessary to arrive at the desired
mixed
light color point.
5 [00151] Where more than two light sources (and/or light engines) are used
(e.g., where there is mixed light of a first color point from a first light
source, light
of a second color point from a second light source, and light of a third color
point
from a third light source), the geometrical relationships can be used to
ensure
that the desired mixed light color point is obtained (e.g., conceptually, the
color
10 point of a sub-mixture of light from the first light source (or the
first light engine)
and the second light source (or the second light engine) can be determined,
and
then the color point of a mixture or sub-mixture (having a brightness of the
combined brightness of the first light source (or the first light engine) and
the
second light source (or the second light engine) and the third light source
(or the
15 third light engine) can be determined, and the range of mixed light
color points
that can be reached is defined by the perimeter obtained from drawing lines
connecting the respective color points of the light sources (and/or light
engines).
[00152] Those skilled in the art will recognize improvements and modifications
to the preferred embodiments of the present disclosure. All such improvements
20 .. and modifications are considered within the scope of the concepts
disclosed
herein and the claims that follow.
