[0001] The present invention-relates to a light-transmitting material which may be employed
as a cover for a winker lamp, brake lamp or the like to be mounted on an automobile,
or as an outer surface member of the indicating sections of illuminated indicators
or decorative means employing light which are provided on household appliances, data
communication equipment or the like.
[0002] A winker lamp, brake lamp or the like of an automobile generally has a white-light
emitting lamp provided therein and a light-transmitting cover colored orange or red,
and is arranged such that, when the lamp is turned on, light emitted therefrom passes
through the colored light-transmitting cover and light Having the color of the cover
is thereby emitted to transmit predetermined information to the surroundings.
[0003] From the viewpoint of allowing the exterior of an automobile to have an attractive
design, it is desirable for these lamps to be such that, when the light source is
in the OFF state, the color of the external surface of the lamp is the same as the
color of the body or exterior trim part of the automobile in the vicinity of the lamp
concerned and, hence, is different from the above-described information transmitting
color, such as red or orange, and that light having a desired information transmitting
color is emitted only when the light source is turned ON. As yet, however, there has
been no example of the practical application of such a technique. There is a similar
demand with respect to the lamps used in a variety of illuminated indicators and decorative
means provided in, for example, the console box which is disposed at the driver's
seat of an automobile.
[0004] In view of the above-described circumstances, it is a primary object of the present
invention to provide a light-transmitting material which may effectively be employed
for the covers of the above-described lamps or those of other illuminated indicators,
and which meets such requirements as those described above.
[0005] To this end, the present invention provides a light-transmitting material comprising
a light-transmitting layer which transmits light and has a light color, and a light-shielding
layer provided on the reverse surface of the light-transmitting layer. The light-shielding
layer is composed of a light-shielding portion which transmits substantially no light
and a light-transmitting portion which is defined by minute slits, a mesh with minute
apertures, or the like, the apertures being provided at a predetermined density. The
light-shielding portion can be given a deep color using a metal coating or an organic
coating.
[0006] By virtue of the above-described arrangement, if the light-transmitting material
according to the present invention is employed as an outer surface member of an illuminated
indicator, when the indicator is in the OFF state, its exterior appears as a composite
color which is composed of the light color of the light-transmitting layer and the
color of the light-shielding layer. If, for example, the light-transmitting layer
is light blue and the light-shielding portion of the light-shielding layer is blue,
when the indecator is in the OFF state, the exterior assumes a deep blue color, whereas
if, for example, the light-transmitting layer is light blue as in the case of the
above and the light-shielding portion is red, the exterior of the indicator when in
the OFF state appears to be reddish purple.
[0007] If the color of the light which is emitted from the inside of the indicator when
turned on (i.e., the color of light from the light source, or the color of light from
the light source when it has passed through a predetermined filter) is made different
from the above-described composite color, the light passing through the light-transmitting
portion of the light-shielding layer and the light-transmitting layer reaches the
surface portion of the indicator without being strongly affected by the light color
of the light-transmitting layer, that is, the color of light reaching the surface
portion is close to the color of light emitted from the light source, so that the
indicating portion is illuminated with light having a color which is different from
the color of the exterior of the indicator when in the OFF state. Accordingly, the
exterior of the indicator when in the ON state assumes a color which is different
from that of the indicator when in the OFF state.
[0008] Thus, appropriate selection of the above-described composite color and the color
of light emitted from the light source enables the color of the exterior of the indicator
when in the ON state to be completely different from that of the indicator when in
the OFF state, thereby allowing the above-described object of the present invention
to be accomplished.
[0009] More specifically, in the illuminated indicator employing the light-transmitting
material of the present invention, the color of the exterior of the indicator when
in the normal OFF state can be selected almost regardless of the color of the exterior
of the indicator when in the ON state (for transmitting predetermined information
to the observer). Accordingly, the indicator concerned and surrounding portions can
generally be designed free from constraints. Further, a change in color of the exterior
as a result of switching the indicator from the OFF state to the ON state gives a
very strong impression to the observer and therefore attracts his attention to the
indicator. Accordingly, the indicator is capable of exhibiting a superior information
transmitting function. In particular, if the light-transmitting portion of the light-shielding
layer is formed in the shape of a desired character, pattern or the like, when the
indicator is turned on, a pattern of a color which is completely different from the
color of the exterior suddenly appears, which effectively attracts the observer's
attention. In addition, the difference between the color of the illuminated character,
pattern or the like when the indicator is in the ON state and the composite color
of the background thereof represents an excellent visual design feature by its use
of a sharp contrast and advantageous effects. Since the light-transmitting material
according to the present invention has the light-shielding layer having the above-described
structure, the interior of an illuminated indicator employing such a light-transmitting
material can be made completely invisible from the outside when the indicator is in
the normal state.
[0010] The above and other objects, features and advantages of the present invention will
become clear from the following description of the preferred embodiments thereof taken
in conjunction with the accompanying drawings.
Fig. 1 is a sectional view of an illuminated indicator employing a light-transmitting
material according to the present invention;
Fig. 2 is a front view of a light-transmitting material according to one embodiment
of the present invention;
Fig. 3 is a sectional side view of the light-transmitting material shown in Fig. 2;
Figs. 4 and 5 are front and sectional side views, respectively, of a light-transmitting
material according to another embodiment of the present invention;
Figs. 6(a), 6(b), Figs. 7(a) and 7(b) and Figs. 8(a) and 8(b) are perspective views
respectively showing different illuminated indicators which utilize the present invention,
in which Figs. 6(a), 7(a) and 8(a) show the illuminated indicators in the OFF state,
and Figs. 6(b), 7(b) and 8(b) show the illuminated indicators in the ON state;
Fig. 9 is an exploded perspective view schematically showing a conventional illuminated
indicator having an ordinary structure;
Figs. 10, 12, 13 and 14 are chromaticity graphs respectively showing results of different
tests; and
Fig. 11 is a chromaticity graph having hue names added thereto.
[0011] The present invention will be described hereinunder in detail by way of embodiments
and with reference to the accompanying drawings.
[0012] Fig. 1 shows a basic arrangement of an illuminated indicator 12 such as a winker
lamp, a brake lamp or an indicator in a console box provided in an automobile, the
indicator 12 employing as its outer surface member or cover a light-transmitting material
10 according to a first embodiment of the present invention.
[0013] The indicator 12 has a casing 14, a lamp 16 as a light source and a color filter
18 which is disposed on the inner side of the light-transmitting material (surface
member) 10. In the case where the illuminated indicator 12 is, for example, a winker
lamp, the filter 18 is defined by an orange filter which transmits only orange light.
[0014] Figs. 2 and 3 show the light-transmitting material 10 in detail. The light-transmitting
material 10 consists of an outer light-transmitting layer 22 which is only slightly
tinted with such light colors as blue, red or white and an inner light-shielding layer
24 which is formed on the reverse surface of the light-transmitting layer 22. The
light-shielding layer 24 has a light-shielding portion 26 which is made of a metal
or a non-light transmitting paint and which transmits substantially no light, and
a light-transmitting portion 28 which is defined by a multiplicity of apertures which
are formed in the light-shielding portion 26 at a predetermined density.
[0015] The light-transmitting layer 22 is defined by a colored sheet or film made of acrylic,
polyester, polycarbonate, nylon or other synthetic resins, or colored glass. The light-transmitting
layer 22 does not necessarily need to be completely transparent so long as it transmits
light.
[0016] Although in the illustrated embodiment the apertures defining the light-transmitting
portion 28 are formed in the light-shielding layer 24 in the form of a mesh, they
may be shaped and arranged as desired. For example, the apertures may be defined by
slits. The light-shielding layer 24 may be formed by any of the following various
methods. (1) A metal layer is formed on the reverse surface of the light-transmitting
layer 22 by vacuum deposition or sputtering, and a mask which corresponds to the pattern
of the light-shielding portion 26 of the light-shielding layer 24 is formed on the
metal layer by means of pattern printing or a photoresist technique. Then, the non-masked
portion is removed by etching to define the light-transmitting portion 28.
[0017] In another example of this type of method of forming the light-shielding layer 24,
the reverse surface of the light-transmitting layer 22 is first colored by pattern
printing, and a metal layer is then formed thereon. Thereafter, a mask is formed on
the metal layer by pattern printing or a photoresist technique, and the non-masked
portion is removed by etching.
(2) A non-light transmitting coating of a metal, paint or ink is formed on the reverse
surface of the light-transmitting layer 22 by means of vapor deposition, sputtering,
painting, printing or a combination thereof. Then, the coating is removed in accordance
with the pattern of the light-transmitting portion 28 using, for example, a laser
beam.
(3) A hot stamping foil having apertures defining the light-transmitting portion 28
is hot-stamped on the reverse surface of the light-transmitting layer 22 to thereby
attach a coating.
(4) Pattern printing is effected on the reverse surface of the light-transmitting
layer 22 using a non-light transmitting ink.
(5) A black pattern is formed on the reverse surface of the light-transmitting layer
22 utilizing a photographic developing process to define the light-shielding layer
24.
[0018] Figs. 4 and 5 show in combination a light-transmitting material 10' in accordance
with a second embodiment of the present invention. As will be understood from Fig.
5, this light-transmitting material 10' consists of two plate materials 30 and 32.
The plate material 30 is a light-transmitting material having a light color which
is similar to the light-transmitting layer 22 in the first embodiment, and defines
a light-transmitting layer 22' in the second embodiment. The second plate material
32 is defined by a light-transmitting sheet or film made of acrylic, polyester, polycarbonate,
nylon or other synthetic resins, or a light-transmitting sheet of glass. A light-shielding
layer 24' is formed on the obverse surface of the plate material 32 by a method similar
to that employed to form the light-shielding layer 24 in the first embodiment.
[0019] In actual use of an illuminated indicator 12 employing the above-described light-transmitting
material 10 or 10' as its surface member, when the lamp 16 provided therein is in
the OFF state, the exterior of the indicator 12 assumes a color representing a combination
of the color of the light-transmitting layer 22 or 22' of the light-transmitting material
10 or 10' and the color of the outer surface of the light-shielding layer 24 or 24'.
If, for example, the light-transmitting layer 22 or 22' is light blue and the outer
surface of the light-shielding layer 24 or 24' is deep blue, the exterior of the indicator
12 when in the OFF state appears to be a deep blue. Since, in this case, the external
light is prevented from entering the interior of the indicator 12 by means of the
light-shielding layer 24 or 24', there is substantially no risk of the interior of
the indicator 12 being seen. If the size of the apertures provided in the light-shielding
layer 24 or 24' is made sufficiently small, they can hardly be seen unless special
attention is given.
[0020] When the illuminated indicator 12 is turned ON, the light emitted from the lamp 16
passes through the filter 18 and is transmitted by the light-transmitting portion
28 or 28' of the light-shielding layer 24 or 24' and the light-transmitting layer
22 or 22' to the outside. Accordingly, light of a predetermined color, for example,
orange light in the case of an orange filter 18, is transmitted by the light-transmitting
portion 28 or 28' and the light-transmitting layer 22 or 22'. Since the light-transmitting
layer 22 or 22
1 is only slightly tinted as described above, the color of light which is transmitted
therethrough is only slightly changed; in the case, for example, of an orange filter
18, the orange light is emitted to the outside with substantially no change in color.
[0021] Figs. 6(a) and 6(b) show in combination an indicator 12 which is designed to be capable
of emitting three different kinds of light by utilizing the above-described basic
illuminated indicator arrangement. More specifically, the outer light-transmitting
layer made of the light-transmitting material 10 of this indicator 12 is slightly
tinted black, the light-shielding layer of the material 10 is formed from a black
paint, and the light-transmitting portion in the light-shielding layer is defined
by three square regions which are spaced apart from each other. The lamp provided
inside the indicator 12 is defined by a lamp emitting white light, and three filters,
that is, orange, red and transparent filters, are provided in that order from the
right-hand side as viewed in the figure in correspondence with the three light-transmitting
regions, respectively. It should be noted that the transparent filter may be omitted
as desired.
[0022] Accordingly, when the indicator 12 is in the OFF state (shown in Fig. 6(a)), the
surface thereof assumes a deep black color, whereas when the indicator 12 is in the
ON state (shown in Fig. 6(b)), orange, red and white rays of light are emitted from
the three light-transmitting regions in that order from the right to the left as viewed
in the f.igure.
[0023] Figs. 7(a) and 7(b) show in combination an illuminated indicator 12 having an arrangement
similar to that of the indicator 12 shown in Figs. 6(a) and 6(b). The indicator 12
shown in Figs. 7(a) and 7(b) mainly differs from that shown in Figs. 6(a) and 6(b)
in that the light-transmitting regions in the light-shielding layer are arranged in
the shape of A, B and C so as to display desired patterns.
[0024] Figs. 8(a) and 8(b) show in combination still another example of an application of
the present invention. The indicator 12 in this example is arranged such that the
light-transmitting layer 22 of the light-transmitting material 10 is colored light
blue and three light-transmitting regions provided in the light-shielding layer 24
are respectively colored green, red and blue in that order from the right to the left
as viewed in the figures, so that, when the light source is in the OFF state, the
light-transmitting regions appear to be blue-green, red-purple and blue, respectively,
from the right to the left.
[0025] The filter of this indicator 12 is defined by a red filter. Accordingly, when the
indicator 12 is turned on, the external portions which appear to be blue-green, red-purple
and blue, respectively, when the device is in the OFF state are all illuminated with
red light. It should be noted that in this case a lamp which emits red light may be
employed in place of the white-light emitting lamp to eliminate the need to employ
a red filter.
[0026] To confirm the functional effects of the present invention, the following tests were
carried out.
(Test 1)
[0027] An illuminated indicator according to the present invention and a conventional illuminated
indicator of this type having a structure such as that shown in Fig. 9 were tested
under the following conditions.
[0028] In the indicator according to the present invention, the light-transmitting material
had the structure shown in Figs. 4 and 5. The light-transmitting layer 22' was defined
by a light-transmitting material colored light blue, and the light-shielding layer
24' was produced in such a manner that a metal coating was formed on the surface of
the plate material 32 by means of sputtering and a pattern of a light-shielding portion
was printed on the metal coating with deep blue ink to form a mask, and the metal
coating was then subjected to etching to form light-transmitting portions.
[0029] The surface wall material 40 of the indicator shown in Fig. 9 was made by coating
a transparent acrylic sheet with a blue paint.
[0030] The lamps 16 and 42 (emitting orange light) of both the indicators were defined by
tungsten-filament lamps and the filters 18 and 44 were defined by orange filters.
The results of the test are shown in Table 1 below. In Table 1, "transmittance" is
the transmittance of the light-transmitting material 10' of the indicator according
to the present invention and that of light transmitted by the surface wall material
40 of the indicator shown in Fig. 9, and "illuminance" means the illuminance of the
transmitted light.

[0031] The following facts will be observed from Table 1. In the case where both the indicators
have the same level of transmittance and their respective exteriors colored blue and
are so designed that the interior of the indicators cannot be seen from the outside
when they are in the OFF state, if these indicators are turned on, the colored light
emitted from the indicator according to the present invention is much brighter than
that from the indicator shown in Fig. 9 and is yellow-orange, which is close to the
color of light from the light source, without being affected by the blue color of
the light-transmitting layer. The term "color of light from the light source" is used
herein to mean the color of light which is transmitted by the filter to pass through
the light-transmitting material. The relationship between the color of light from
the light source and the color of the transmitted light may be illustrated by a chromaticity
diagram such as that shown in Fig. 10.
(Test 2)
[0032] In this test, the two indicators were compared with each other under conditions where
the illuminance of the transmitted light was set at the same level. The filter was
removed from each indicator, and a tungsten-filament lamp alone was employed for the
light source.
(a) Results of the test in the case where, when the light source is in the OFF state,
the chromaticity of the exterior is red are shown in Table 2 and Fig. 12. The results
show that the change in the color of the transmitted light with respect to the color
of light from the light source is much smaller in the indicator according to the present
invention than in the indicator shown in Fig.-9.

(b) Results of the test in the case where, when the light source is in the OFF state,
the chromaticity of the exterior is blue are shown in Table 3 and Fig. 13. The results
show that the change in the color of the transmitted light with respect to the color
of light from the light source is much smaller in the indicator according to the present
invention than in the indicator shown in Fig. 9.

(Test 3)
[0033] The two indicators were compared with each other under conditions where the chromaticity
of the transmitted light was set to be the same.
[0034] The filter was removed from each indicator and a tungsten-filament lamp alone was
employed for the light source in the same way as in the case of Test 2. Results of
the test are shown in Table 4. A chromaticity diagram corresponding to Table 4 is
shown in Fig. 14. It will be understood from the results of the test that, as the
chromaticity of the transmitted light in the indicator shown in Fig. 9 is made to
approach the color (orange) of light from the light source, the external appearance
at the time when the indicator is in the OFF state is almost transparent and has a
light orange-pink color which is closer to an achromatic color and the transmittance
is considerably high, i.e., 70%, which means that the interior is fully exposed to
view.

[0035] As will have been understood from the above, the light-transmitting material according
to the present invention permits the color of light transmitted thereby to be close
to the color of light from the light source without being affected by the color of
the external surface. Accordingly, this light-transmitting material is capable of
meeting the requirements described in the section entitled "Background of the Invention".
[0036] Although the present invention has been described through specific terms, it should
be noted here that the described embodiments are not necessarily limitative and that
various changes and modifications may be imparted thereto without departing from the
scope of the invention which is limited solely by the appended claims.
1. - A light-transmitting material which is used as an outer surface member of a device
having a light source therein and which is illuminated with light from the light source
when turned on, said material comprising:
a light-transmitting layer which transmits light and is tinted with a light shade
of color; and
a light-shielding layer provided on or adjacent the reverse surface of said light-transmitting
layer, said light-shielding layer being composed of a light-shielding portion which
transmits substantially no light and a light-transmitting portion which is defined
by minute apertures, slits or the like provided at a predetermined density,
whereby, when said light source is not turned on, the exterior of said light-transmitting
material appears to be a composite color which is composed of the color of said light-shielding
portion and the color of said light-transmitting layer.
2. A light-transmitting material according to Claim 1, wherein said light-transmitting
portion of said light-shielding layer is defined by an organic coating of a paint,
ink or the like.
3. A light-transmitting material according to Claim 1, wherein said light-shielding
portion of said light-shielding layer is defined by a metal coating.
4. A light-transmitting material according to Claim 1, wherein said light-shielding
portion of said light-shielding layer is defined by a combination of a metal coating
and an organic coating.
5. A light-transmitting material according to Claim 4, wherein said light-transmitting
layer and said light-shielding layer are formed on a single substrate.
6. A light-transmitting material according to Claim 1, wherein said light-transmitting
layer and said light-shielding layer are formed on a single substrate.
7. A light-transmitting material according to Claim 2, wherein said light-transmitting
layer and said light-shielding layer are formed on a single substrate.
8. A light-transmitting material according to Claim 3, wherein said light-transmitting
layer and said light-shielding layer are formed on a single substrate.
9. A light-transmitting material according to Claim 4, wherein said light-transmitting
layer and said light-shielding layer are respectively formed on substrates which are
independent of each other.
10. A light-transmitting material according to Claim 1, wherein said light-transmitting
layer and said light-shielding layer are respectively formed on substrates which are
independent of each other.
11. A light-transmitting material according to Claim 2, wherein said light-transmitting
layer and said light-shielding layer are respectively formed on substrates which are
independent of=each other.
12. A light-transmitting material according to Claim 3, wherein said light-transmitting
layer and said light-shielding layer are respectively formed on substrates which are
independent of each other.