LAMP WITH HEAT-RESPONSIVE DECORATION

LAMPE A DECORATION SENSIBLE A LA CHALEUR

English Abstract

A lighting product including a holder for an
illumina-tion source, a frame, attached to the holder including a back plate
having a front surface adjacent to the illumination source, and a
lay-er of a thermochromic material, which is disposed on the front
sur-face of the back plate so as to alter an appearance of the back plate in
response to heat emitted by the illumination source.

French Abstract

L'invention porte sur un produit d'éclairage comprenant un support pour une source d'éclairage, un cadre attaché au support comprenant une plaque arrière ayant une surface avant adjacente à la source d'éclairage, et une couche d'un matériau thermochromique, qui est agencée sur la surface avant de la plaque arrière de façon à modifier une apparence de la plaque arrière en réponse à de la chaleur émise par la source d'éclairage.

Claims

CLAIMS
1. A lighting product, comprising:
a holder for an illumination source;
a frame, attached to the holder and comprising a back
plate having a front surface adjacent to the illumination
source; and
a layer of a thermochromic material, which is disposed on
the front surface of the back plate so as to alter an
appearance of the back plate in response to heat emitted by
the illumination source.
2. The product according to claim 1, wherein the
illumination source is a candle.
3. The product according to claim 1, wherein the frame
comprises a base, upon which the holder and the back plate are
mounted.
4. The product according to claim 3, wherein the back plate
has a back surface opposite the front surface, and wherein the
frame comprises a protective plate mounted on the base
adjacent to the back surface of the back plate.
5. The product according to claim 1, wherein the back plate
comprises a canopy that extends forward over the illumination
source.
6. The product according to claim 1, wherein the
thermochromic material is opaque at an ambient temperature of
the product and becomes transparent in response to the heat
emitted by the illumination source.
7. The product according to claim 6, wherein an image is
disposed on the front surface of the back plate, beneath the
layer of the thermochromic material, so that the image becomes
visible as the thermochromic material becomes transparent.
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8. The product according to claim 7, wherein the image on
the front surface of the back plate is a first image, and
wherein the layer of the thermochromic material comprises a
second image, which is visible at the ambient temperature and
becomes transparent in response to the heat so as to reveal
the first image.
9. A method for lighting, comprising:
mounting a holder for an illumination source on a frame
comprising a back plate so that a front surface of the back
plate is adjacent to the illumination source; and
providing, on the front surface of the back plate, a
layer of a thermochromic material that alters an appearance of
the back plate in response to heat emitted by the illumination
source.
10. The method according to claim 9, wherein the illumination
source is a candle.
11. The method according to claim 9, wherein the frame
comprises a base, upon which the holder and the back plate are
mounted.
12. The method according to claim 11, wherein the back plate
has a back surface opposite the front surface, and wherein the
frame comprises a protective plate mounted on the base
adjacent to the back surface of the back plate.
13. The method according to claim 9, wherein the back plate
comprises a canopy that extends forward over the illumination
source.
14. The method according to claim 9, wherein the
thermochromic material is opaque at an ambient temperature and
becomes transparent in response to the heat emitted by the
illumination source.
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15. The method according to claim 14, and comprising forming
an image on the front surface of the back plate, beneath the
layer of the thermochromic material, so that the image becomes
visible as the thermochromic material becomes transparent.
16. The method according to claim 15, wherein the image on
the front surface of the back plate is a first image, and
wherein the method comprises forming, in the layer of the
thermochromic material, a second image, which is visible at
the ambient temperature and becomes transparent in response to
the heat so as to reveal the first image.
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Description

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LAMP WITH HEAT-RESPONSIVE DECORATION-
FIELD OF THE INVENTION
The present invention relates generally to decorative
lighting, and specifically to lamp and candle holders.
BACKGROUND OF THE INVENTION
The use of thermochromic materials in decorative lighting
is known in the art. For example, U.S. Patent 6,544,448,
whose disclosure is incorporated herein by reference,
describes a luminary device with a thermochromic label. A
decorative web of heat-shrinkable polymer is heat-shrunk to
conform to the shape of a candle or candle holder. The web is
decorated with a thermochromic ink or pigmentation, which
changes visibly when the candle is burned.
SUMMARY OF THE INVENTION
In embodiments of the present invention, a lighting
product comprises a holder for an illumination source, such as
a candle, and a frame, which is attached to the holder. The
frame comprises a back plate having a front surface adjacent
to the illumination source. A layer of a thermochromic
material, disposed on the front surface of the back plate,
alters the appearance of the back plate in response to heat
emitted by the illumination source.
In a disclosed embodiment, the thermochromic material is
opaque at ambient temperature and becomes transparent in
response to the heat emitted by the illumination source. An
image on the front surface of the back plate, beneath the
layer of the thermochromic material, becomes visible as the
thermochromic material becomes transparent. The layer of the
thermochromic material may optionally comprise a second image,
which is visible at the ambient temperature and becomes
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transparent in response to the heat so as to reveal the first
image.
The present invention will be more fully understood from
the following detailed description of the embodiments thereof,
taken together with the drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic, pictorial illustration of a
lighting product, in accordance with an embodiment of the
present invention;
Figs. 2A and 2B are schematic, pictorial illustrations
showing a reaction of the lighting product of Fig. 1 to heat
emitted by a candle, in accordance with an embodiment of the
present invention; and
Fig. 3 is a schematic, sectional illustration of the
lighting product of Fig. 1, in accordance with an embodiment
of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Fig. 1 is a schematic, pictorial illustration of a
lighting product 20, in accordance with an embodiment of the
present invention. Product 20 comprises a frame 21,
comprising a base 22 and a back plate 26 mounted on the base.
A holder 24 for an illumination source is also mounted on base
22. In this embodiment, holder 24 is designed to hold a
candle, but the holder may alternatively be adapted to hold
any suitable sort of illumination source, such as an electric
lamp or oil with a wick, which serves as an oil lamp.
Back plate 26 is roughly perpendicular to base 22. The
front surface of back plate 26 (i.e., the surface that is seen
by a user or viewer of product 20 and is shown in this
figure), adjacent to holder 24, is covered by a layer of
thermochromic material, which responds to heat emitted by the
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illumination source, as is described further with reference to
the figures that follow. Back plate 26 may also comprise a
canopy 28, which extends forward over the illumination source
in holder 24 and may help in capturing the heat emitted by the
illumination source. A protective plate 30 may be mounted
behind the back surface of the back plate in order to protect
people and objects from exposure to the hot back plate.
Although the elements of frame 21 are shown in Fig. 1 as
having a certain geometry and decorative features, these
aspects of product 20 are shown only by way of illustration.
Alternative geometries and features that fulfill the functions
described herein are likewise considered to be within the
scope of the present invention.
Reference is now made to Figs. 2A and 2B, which are
schematic, pictorial illustrations showing the reaction of
product 20 to heat emitted by a candle 32 in holder 24. Fig.
2A shows the appearance of back plate 26 immediately after
lighting the candle, whereas Fig. 2B shows the change in
appearance of the back plate after heating by the candle for a
period of time.
An image 34 is disposed on the front surface of back
plate 26, and a layer of thermochromic material is formed over
the image. The thermochromic material is chosen so that at
ambient temperature (for example, in the range of 20 C), the
thermochromic layer is opaque, and image 34 is hidden from
view, as shown in Fig. 1. As the temperature of back plate 26
rises, the thermochromic material gradually becomes
transparent, and image 34 is revealed, as shown in Figs. 2A
and 2B. The thermochromic layer may be uniform, so that back
plate 26 is blank until heated by candle 32. Alternatively,
the thermochromic material may comprise a second image (not
shown), overlying image 34, so that the second image is
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visible at ambient temperature and becomes transparent in
response to the heat from candle 32 so as to reveal the first
image.
Fig. 3 is a schematic, sectional view of product 20,
taken along the line III-III in Fig. 1, in accordance with an
embodiment of the present invention. Typically, base 22, back
plate 26 and protective plate 30 are made from a suitable
metal, such as brass. Alternatively, some or all of these
parts may be made from other materials, such as ceramic,
glass, or heat-resistant plastic. Although a back surface 40
of back plate 26 is shown in this figure as being in contact
with protective plate 30, there may alternatively be an air
gap or other insulating layer between surface 40 and plate 30.
A layer 44 of pigment, defining image 34, is disposed on
a front surface 42 of back plate 26 and is overlaid by a layer
46 of thermochromic material. Layers 44 and 46 may be printed
directly onto surface 42, or they may alternatively be printed
on a substrate, such as chromo paper, which is then glued onto
or otherwise affixed to the surface. Layer 44 may comprise
any suitable ink, and image 34 is typically printed in this
layer using a standard monochrome or four-color printing
process.
Layer 46 may comprise any suitable type of thermochromic
material, such as a leuco-based ink or pigment, as is known in
the art. The type of material and thickness of layer 46 are
chosen so that the layer becomes transparent at the desired
temperature. In the kind of design shown in Figs. 1-3, using
candle 32 as the source of heat, layer 46 is typically printed
to a thickness of 1.5 - 2 m. A dark-colored leuco dye may be
advantageous to hide image 34 completely until back plate 26
is heated. A second image, which is seen when back plate 26
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is at ambient temperature, may be printed in layer 46 or over
layer 46 using an additional thin layer of thermochromic ink.
Alternatively, layer 44 may be omitted, and the desired
image may be formed in layer 46 using a suitable thermochromic
material so that the image is invisible at ambient temperature
and becomes visible when the thermochromic material is heated.
It will be appreciated that the embodiments described
above are cited by way of example, and that the present
invention is not limited to what has been particularly shown
and described hereinabove. Rather, the scope of the present
invention includes both combinations and subcombinations of
the various features described hereinabove, as well as
variations and modifications thereof which would occur to
persons skilled in the art upon reading the foregoing
description and which are not disclosed in the prior art.

Representative Drawing