Note: Descriptions are shown in the official language in which they were submitted.
PATENT APPLICATION
for
PRISMATIC LED MODULE FOR LUMINAIRE
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional patent
application No. 61/591,619, filed January 27, 2012.
FIELD OF THE INVENTION
[0002] The invention relates to the field of lighting and concerns luminaires
utilizing light emitting diodes (LEDs) for illuminating an area. More
particularly, the invention concerns LED modules that can be arrayed in a
luminaire to provide a desired level, direction and pattern of illumination.
BACKGROUND
[0003] Commonly owned U.S. Patent No. 8,342,709, which may be referred
to for further details, discloses various arrays of LED modules that snap into
relatively large rectangular openings in a luminaire carrier plate. A portion
of
each module's heat sink extends into the luminaire housing above the carrier
plate, and each module has a four-sided reflector that shapes and directs the
light emitted by a row of LEDs mounted on a circuit board.
SUMMARY OF THE INVENTION
[0004] The LED module of the present invention has a downwardly directed
heat sink and is adapted for installation on the underside of a luminaire
carrier
plate. The heat sink comprises a front end having a front face, a top wall
extending rearward from the front end, and a plurality of cooling fins
extending
rearward from the front end and downward from the top wall. The top wall has
a top face for abutting the underside of the luminaire carrier plate. A
circuit
board carrying at least one LED is mounted on the front face, and a prism is
mounted to the heat sink over the LED(s). The top face preferably is disposed
at an acute angle to the front face, and the cooling fins preferably taper in
height from the front end rearward.
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[0005] Another aspect of the invention is a catadioptric prism per se for
shaping and directing light emitted by an even number of aligned, laterally
spaced LEDs. The prism has a transparent body with a fore-and-aft medial
vertical plane and comprises a rear light-receiving face, a front light-
emitting
face, a top face, a bottom face and two side faces. The front face has several
prominent sections, as follows. A lower section on each side of the medial
vertical plane has a substantially vertical front, and substantially vertical
curved sides that merge with the front. A middle section on each side of the
medial vertical plane and above the lower section is wider than it is high and
has a substantially horizontal rounded face with rounded ends that merge with
the rounded face. An upper section, which is above both middle sections, has
a downwardly and forwardly slanted surface. The rear face of the prism has a
convex cradle section on each side of the medial vertical plane. Each cradle
section has at least one pocket behind the middle section of the front face
for
cradling an LED; and the pockets are symmetrically disposed on opposite sides
of the medial vertical plane. The prism preferably is bilaterally symmetrical
about the medial vertical plane.
[0005A] A further broad aspect pertains to an LED lighting module for
installation on the underside of a luminaire carrier plate comprising: a
metallic
heat sink including: a front end having a front face, a top wall extending
rearward from the front end and having a top face for abutting the underside
of
the carrier plate. A plurality of cooling fins extends rearward from the front
end and downward from the top wall. A circuit board is mounted on the front
face and carries at least one LED. A prism is mounted to the heat sink over
the at least one LED.
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[0005B]
Further still, the invention comprehends a luminaire comprising: a
housing having a top portion and a bottom portion, the bottom portion
including a carrier plate. A plurality of lighting modules each including a
metallic heat sink with a flat upper wall abut the carrier plate. A front face
is
adjacent the upper wall and two or more parallel cooling fins are disposed
below and perpendicular to the flat upper wall and the front face. The flat
upper wall of the plurality of lighting modules is disposed at an acute angle
to
the front face. The plurality of lighting modules each further include a
circuit
board disposed on the front face and carrying at least one light emitting
diode
(LED), and a prism disposed on the heat sink over the at least one LED.
BRIEF DESCRIPTION OF THE DRAWING
[0006] Preferred embodiments of the disclosed invention, including the best
mode for carrying out the invention, are described in detail below, purely by
way of example, with reference to the accompanying drawing figures, in which:
[0007] Fig. 1 is a perspective view of an LED module according to the
invention, taken from the front and left side thereof;
[0008] Fig. 2 is a side elevational view thereof;
[0009] Fig. 3 is a bottom plan view thereof;
[0010] Fig. 4 is an exploded view thereof;
[0011] Fig. 5 is a perspective view of the heat sink portion of the module of
Fig. 1 taken from the front, top and left side;
[0012] Fig. 6 is a perspective view thereof taken from the front, bottom and
left side;
2A
Date Recue/Date Received 2020-10-08
CA 02804118 2013-01-25
[0013] Fig. 7 is a bottom perspective view of a luminaire having a particular
array of LED modules according to Figs. 1-4 installed therein;
[0014] Fig. 8 is a bottom plan view thereof;
[0015] Figs. 9 through 13 are schematic illustrations of five different light
beam patterns producible by five different arrays of LED modules according to
the invention;
[0016] Fig. 14 is a perspective view of a prism of the invention taken from
the
front, top and right side thereof;
[0017] Fig. 15 is a perspective view thereof taken from the front, bottom and
right side;
[0018] Fig. 16 is a perspective view thereof taken from the rear, top and
right
side;
[0019] Fig. 17 is a perspective view thereof taken from the rear, bottom and
right side;
[0020] Fig. 18 is a top plan view thereof;
[0021] Fig. 19 is a front elevational view thereof;
[0022] Fig. 20 is a bottom plan view thereof;
[0023] Fig. 21 is a right-side elevational view thereof;
[0024] Fig. 22 is a left-side elevational view thereof;
[0025] Fig. 23 is a rear elevational view thereof;
[0026] Fig. 24 is a cross-sectional view thereof taken along line 24-24 in
Fig.
23;
[0027] Fig. 25 is a cross-sectional view thereof taken along line 25-25 in
Fig.
23;
[0028] Fig. 26 is a cross-sectional view thereof taken along line 26-26 in
Fig.
23;
[0029] Fig. 27 is a left-side elevational view thereof showing LED light ray
traces reflecting, refracting and emanating from the left half thereof; and
[0030] Fig. 28 is a top plan view thereof showing LED light ray traces
reflecting, refracting and emanating from the right half thereof.
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DETAILED DESCRIPTION OF THE INVENTION
[0031] As used in this application, including the claims, terms such as
"front," "rear," "side," "top," "bottom," "above," "below," "upward,"
"downward,"
"lateral," "vertical" and "horizontal" are used in a relative sense to
facilitate the
description of the invention, and are not intended to limit the invention to
any
particular position or orientation except when clearly describing its
orientation
in an installed, operational position.
[0032] Referring to Figs. 1-6, an exemplary sealed LED module 8 according
to the invention comprises an optically clear prism 10 secured by two screws
12 to the front of a wedge-shaped heat sink 14 over a printed circuit board
(PCB) 16, which carries four aligned, laterally spaced LEDs 18 symmetrically
arranged in two pairs. A thermal paste or other conventional heat transfer
medium preferably is interposed between PCB 16 and the front face of heat
sink 14. A rectangular gasket 13 is disposed between prism 10 and heat sink
14 to surround and seal PCB 16 from the environment. A hole 20 in PCB 16
and holes 22, 24 in heat sink 14 enable routing of power conductors (not
shown) through the heat sink to the PCB.
[0033] Heat sink 14 preferably is made of anodized, die cast aluminum and
has a series of parallel vertical cooling fins 26 on its underside. The
penultimate cooling fin on each side is shortened to make room for a mounting
hole 28 in the top wall 29 of the heat sink, which accommodates a mounting
screw (not shown) from below for attachment to the carrier plate P of a
luminaire (see, e.g., Figs. 7 and 8). A locating stud 30, which projects
upward
from the top wall 29, is adapted to register with a mating feature on the
carrier
plate to ensure proper positioning of the module 8 against the underside of
the
carrier plate. A rectangular central upper gasket (not shown) forms a seal
against the carrier plate around hole 24.
[0034] The array of LED modules 8 shown in Figs. 7 and 8 comprises a
center row of six forward-facing modules flanked on each side by twelve
modules (in two rows of six modules each) that face obliquely toward the
center
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row. Other arrays of modules may be used to provide desired patterns of
illumination. For example, U.S. Patent No. 8,342,709 discloses five exemplary
arrays of LED modules mounted to a luminaire carrier plate to produce the five
different patterns shown in Figs. 18-22 thereof. Figs. 9-13 herein are
substantial reproductions of those figures and show that the same types of
patterns can be produced by arrays of modules 8 according to the present
invention from a luminaire F projecting a light beam B generally along an
optical axis X (the axis corresponding to the maximum candlepower). Those
patterns substantially correspond to the beam shapes specified in IES NEMA
regulations as Type I (Fig. 9); Type II (Fig. 10); Type III (Fig. 11); Type IV
(Fig.
12); and Type V (Fig. 13). The module array of Figs. 7 and 8 will produce a
Type 3 beam shape.
[0035] Due to the slant of heat sink top wall 29, prism 10 will face obliquely
downward when the LED module is mounted to a substantially horizontal
luminaire carrier plate. That orientation and the optical characteristics of
the
prism 10 (described below) will cause the optical axis X to meet a
substantially
horizontal surface to be illuminated at an angle of approximately 60 to 80
off
vertical, preferably about 65 to 70 off vertical as shown in Fig. 27. This
generally will be the situation regardless of luminaire mounting height. Fig.
1
of U.S. Patent No. 8,342,709 schematically illustrates this geometry. As
roughly illustrated by the ray traces in Figs. 27 and 28 herein, about 95% of
the main beam intensity will be within about a 10 to 12 vertical spread by
about a 30 to 40 horizontal spread, and about 5% of the beam intensity will
be aimed downward at about 20' to 25 off vertical to help fill dark spots
below
the luminaire. For the sake of simplicity, Fig. 28 shows the ray traces of
only
one side of prism 10. The ray traces of the other side of the prism are the
mirror image of those shown, with beam overlap in the central region.
[0036] Prism 10 preferably is molded of a UV stabilized, optically clear
acrylic
thermoplastic material having a refractive index of about 1.49. Other
materials
may be used instead, for example, glass or polycarbonate. The optical surfaces
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preferably have a class A polish to maximize internal reflections. Figs. 14-28
show the physical features of the prism, which is bilaterally symmetrical
about
its fore-and-aft medial vertical plane M (see Figs. 19 and 23) and includes a
hollow rectangular mounting base 32 having mounting holes 34 and a
peripheral flange 36 that surrounds PCB 16. The light-shaping portions of
prism 10, which are integrally formed with base 32, are situated centrally and
mostly forward of flange 36 and have a flat bottom 38, flat sides 40 and a
flat
top 42.
[0037] At the front of prism 10 on each side of the medial vertical plane, at
the bottom, is a bulging "breakfront" portion 44 having curved vertical sides
46
and a substantially flat, vertical front face 48. Above breakfront portion 44
is a
horizontal 'semi-tubular" portion 50 with rounded ends 52 and a rounded face
54, which has a radius of curvature that tightens toward its horizontal
center.
Above semi-tubular portion 50 is a horizontal "forehead" bar 56 that spans
both sides and has a slightly slanted "brow" portion 58, which gradually
transitions to a flat, more slanted "crown" portion 60. At the rear of prism
10
on each side of the medial vertical plane is a convex, horizontally elongated
"cradle" portion 62, which has two side-by-side pockets (recesses) 64
separated
by a vertical rib 66. Each pocket 64 cradles an LED 18 (see Figs. 2 and 3). As
seen in Fig. 27, it is forehead bar 56 that directs the small portion (about
5%)
of the beam intensity downward to help fill dark spots below the luminaire.
[0038] While exemplary embodiments have been chosen to illustrate the
invention, it will be understood by those skilled in the art that various
changes,
modifications, additions, and substitutions are possible, without departing
from the scope and spirit of the invention.
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