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Description  |
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The present invention relates to a light-shielding screen device. More
particularly, the present invention is concerned with a light-shielding
screen device comprising a first light transmissible substrate, a second
light transmissible substrate and an intermediate layer sandwiched
therebetween. The intermediate layer comprises at least one
light-shielding screen portion located in the middle area of the
intermediate layer and a light non-transmissible retaining portion located
at least in a portion of the remaining area of the intermediate layer, the
portion of the remaining area including the entire outermost peripheral
area of the intermediate layer, thereby causing the intermediate layer
comprising at least one light-shielding screen portion to be securely held
between the first light transmissible substrate and the second light
transmissible substrate.
As is well known, a light-shielding screen has been used for extraneous
light rays-shielding applications in various image-indicating devices such
as television receivers, various computer-related displays having a CRT
(cathode-ray tube), various indicators such as indicators for instruments,
traffic signals and the like. Recently, in various indicators mounted on
an instrument panel of an automobile and adapted to emit signals by means
of a light from a lamp, a light-shielding screen having an image such as
letter or mark printed thereon has been increasingly used for shielding
extraneous light rays incident on the signal devices, and for shielding
the light emitted in the unnecessary directions from the lamp, thereby to
regulate the visible angle range of the image illuminated by the lamp.
For example, Japanese Patent Application Laid-Open Specification Nos.
57-89701/1982 and 57-165802/1982 disclose a light-shielding screen
comprising a transparent plate and a plurality of relief lines of a
photocured resin composition provided on the entire surface of one side of
the transparent plate, the relief lines being arranged to form a striped
pattern structure or a lattice pattern structure. The light-shielding
screen disclosed in the above-mentioned Japanese Patent Application
Laid-Open Specifications may be used for television receivers, various
computer-related displays having a CRT and the like. However, it is noted
that with respect to indicators of push button type switches which have
been increasingly incorporated in an automobiles, the above-mentioned
conventional light-shielding screen cannot be advantageously used. The
reason for this is as follows. When the above-mentioned light-shielding
screen is used in a push button type signal indicator, another transparent
plate is securely attached to the relief on the transparent plate. In
other words, the relief lines are sandwiched as an intermediate layer
between the two transparent plates. If desired, a plurality of
predetermined images are then printed on one of the transparent
substrates. Subsequently, the resulting product is cut into a plurality of
sections each having an image thereon,if any. The section serving as an
indicator is securely attached to a knob of a push button type switch
which is adapted to actuate a lamp to illuminate the indicator means in
synchronization with the on-operation of the switch. As mentioned above,
in the conventional light-shielding screen, the relief lines are formed as
an intermediate layer on the entire surface of the transparent plate.
Therefore, the area of bonding between the intermediate layer and the
transparent plates is small. Because of the small bond area, the bonding
strength between the intermediate layer and the transparent plates is
poor. For this reason, in preparing an indicator means by cutting the
light-shielding screen into a plurality of sections, the transparent
plates inevitably tend to peel off from the intermediate layer of relief
lines sandwiched between the two transparent plates. Even though in
cutting the light-shielding screen into a plurality of sections, the
transparent plates do not peel off from the intermediate layer, the
section obtained cannot be advantageously used as an indicator means for
push button type switches. Specifically, since in a push button type
switch as constructed in the above-mentioned manner, the indicator means
is repeatedly pushed for switching an instrument on or off connected to
the switch, the indicator means should have a high mechanical strength. As
mentioned above, the indicator means made of the conventional
light-shielding screen is extremely poor in bond strength between the
transparent plates and the intermediate layer and, hence, the transparent
plates unfavorably tend to peel off from the intermediate layer in a short
period of time. As is apparent from the foregoing, the conventional
light-shielding screen is poor in bond strength between the transparent
plates and the intermediate layer and, hence, the applications therefor
were limited to those where a high mechanical strength is not required.
The present inventors have made extensive and intensive studies with a goal
toward eliminating the above-mentioned drawbacks of the conventional
light-shielding screen and toward providing a light-shielding screen which
has a high mechanical strength sufficient for use as an indicator means of
push button type switches. As a result, the present inventors have found
that a light-shielding screen device comprising a first and a second light
transmissible substrate and an intermediate layer provided between the
first and second light transmissible substrates and comprising at least
one light-shielding screen portion located in the middle area of the
intermediate layer and a light non-transmissible retaining portion located
at least in a portion of the remaining area of the intermediate layer,
which portion of the remaining area includes the entire outermost
peripheral area of the intermediate layer, is excellent in bond strength
between the first and second light transmissible substrates and the
intermediate layer and, hence, can be particularly advantageous for use as
an indicator means of push button type switches.
Based on such a novel finding the present invention has been made.
Accordingly, it is an object of the present invention to provide a
light-shielding screen device having a high mechanical strength.
It is another object of the present invention to provide a light-shielding
screen device, which is simple in structure and can be easily produced at
a low cost.
The foregoing and other objects, features and advantages of the present
invention will be apparent from the following description taken in
connection with the accompanying drawings in which:
FIG. 1 is a front view of one form of a light-shielding screen device
according to the present invention;
FIG. 2 is an enlarged cross-sectional view taken along the line II--II of
FIG. 1;
FIG. 3 is a front view of another form of a light-shielding screen device
according to the present invention;
FIG. 4 is a schematic view explaining the optical mechanism according to
which the light-shielding screen device of the present invention regulates
the visible angle range to attain the light-shielding effect;
FIG. 5 is a front view of a further form of a light-shielding screen device
according to the present invention; and
FIG. 6 is a schematic, perspective view of a push button type switch system
in which a light-shielding screen device of the present invention is
attached to a knob of the switch system.
In FIGS. 1 to 6, like portions or parts are designated by like numerals.
In accordance with the present invention, there is provided a
light-shielding screen device comprising:
(a) a first light transmissible substrate;
(b) an intermediate layer provided on the surface of the first light
transmissible substrate,
the intermediate layer comprising at least one light-shielding screen
portion and a light non-transmissible retaining portion,
the at least one light-shielding screen portion being located in the middle
area of the intermediate layer and the light non-transmissible retaining
portion being located at least in a portion of the remaining area of the
intermediate layer, the portion of the remaining area including the entire
outermost peripheral area of the intermediate layer,
the light-shielding screen comprising a plurality of light-shielding lines;
and
(c) a second light transmissible substrate provided on the surface of the
intermediate layer remote from the first light transmissible substrate,
the light non-transmissible retaining portion of the intermediate layer
securely retaining on its both sides the first light transmissible
substrate and the second light transmissible substrate, respectively.
The light-shielding screen device of the present invention comprises a
first light transmissible substrate, an intermediate layer provided on the
surface of the first transmissible substrate, and a second light
transmissible substrate provided on the surface of the intermediate layer
remote from the first light transmissible substrate. The intermediate
layer is sandwiched between the first light and second transmissible
substrates. The intermediate layer comprises at least one light-shielding
screen portion and a light non-transmissible retaining portion. The
light-shielding screen portion is located in the middle area of the
intermediate layer and the light non-transmissible retaining portion is
located at least in a portion of the remaining area of the intermediate
layer, the portion of the remaining area including the entire outermost
peripheral area of the intermediate layer. The light-shielding screen
comprises a plurality of light-shielding lines. The light
non-transmissible retaining portion of the intermediate layer securely
retains on both its sides the first light transmissible substrate and the
second light transmissible substrate, respectively.
The term "entire outermost peripheral area of the intermediate layer" is
defined as a portion of the intermediate layer which includes the overall
edge of the intermediate layer and a region continuously extending from
the overall edge toward the middle portion in which at least one
light-shielding screen portion is located and having a minimum width
sufficient to retain the first and second light transmissible substrates
on both sides of the intermediate layer. The above-mentioned minimum width
may vary according to the kinds of the materials of intermediate layer and
the first and second light transmissible substrates, but may generally be
about 1.0 mm or more.
Referring now to FIG. 1, there is a front view of one form of a
light-shielding screen device according to the present invention, which
comprises a first light transmissible substrate (not designated there due
to its transparency), an intermediate layer 8 provided on the surface of
the first light transmissible substrate and a second light transmissible
substrate (behind the drawing) provided on the intermediate layer 8. The
intermediate layer 8 comprises a light-shielding screen portion 2 located
in the middle of the intermediate layer 8 and a light non-transmissible
retaining portion 5 entirely located in the remaining area of the
intermediate layer 8.
In FIG. 2 shows an enlarged cross-sectional view taken along the line
II--II of FIG. 1, in which numeral 1 designates a first light
transmissible substrate, numeral 6 a second light transmissible substrate,
numeral 3 light-shielding lines constituting a light-shielding screen in
the intermediate layer 8 and numeral 4 spaces between the light-shielding
lines 3. In the present invention, it is required that the remaining area
of the intermediate layer 8 in which the light non-transmissible retaining
portion 5 is located include the entire outermost peripheral area of the
intermediate layer 8. In other words, the entire outermost peripheral area
of the intermediate layer 8 is securely attached,on one side thereof, to
the surface of the first light transmissible substrate 1 and, on the other
side thereof, to the surface of the second light transmissible substrate
6. By virtue of the above structure, the light-shielding screen device of
the present invention has excellent bond strength between the first and
second light transmissible substrates 1, 6 and the intermediate layer 8.
FIG. 3 shows a front view of another form of a light-shielding screen
device according to the present invention, which comprises a first light
transmissible substrate (not designated there due to its transparency), an
intermediate layer 8 which is provided on the first light transmissible
substrate and which has a light-shielding screen portion 2 located in the
middle of the intermediate layer 8 and a light non-transmissible retaining
portion 5 entirely located in the remaining area of the intermediate layer
8 and a second light transmissible substrate (behind the drawing) on which
an image 7 is printed at the place corresponding to the light-shielding
screen portion 2 of the intermediate layer 8.
FIG. 4 shows a schematic view of the light-shielding effect of the
light-shielding screen device of the present invention in which character
L designates a lamp L and character E an eye of a man, for example, an
automobile driver. The light rays in the direction indicated by an arrow A
reach the eye E of the driver through the spaces 4 between the
light-shielding lines 3 of the light-shielding screen portion 2. On the
other hand, the light rays in the direction indicated by an arrow B are
effectively shielded by the light-shielding lines 3 and, hence, do not
pass through the light-shielding screen device. This prevents the light
rays emitted from the lamp L from diffusing into the inside of the
automobile and reflecting on a windshield, a side mirror or a side window
of the automobile.
FIG. 5 shows a front view of a further form of a light-shielding screen
device according to the present invention, which comprises a first light
transmissible substrate (not designated there due to its transparency), an
intermediate layer 8 provided on the surface of the first light
transmissible substrate and a second light transmissible substrate (behind
the drawing) provided on the intermediate layer 8. The intermediate layer
8 comprises two light-shielding screen portions 9 located in the middle of
the intermediate layer 8 and a light non-transmissible retaining portion
10 entirely located in the remaining area of the intermediate layer 8. The
form of the light-shielding screen device shown in FIG. 5 is characterized
in that the light-shielding screen portion 9 of the intermediate layer 8
is formed in the form of predetermined images 9, 9 as opposed to the form
of the light-shielding screen device shown in FIG. 3 in which the
predetermined images are printed on the light transmissible substrate.
FIG. 6 shows a schematic perspective view of a push button type switch
system mounted on, e.g., the instrument panel of an automobile in which
system a light-shielding screen device of the present invention is used as
an indicator means. In FIG. 6, numeral 11 designates a lamp, numeral 12 a
switch, numeral 13 a light-transmitting tube, numeral 14 a knob and
numeral 15 a light-shielding screen of the present invention as shown in
FIG. 3. The light-shielding screen device 15 as an indicator means is
attached to the knob 14. By pushing the indicator means 15 the lamp 11 is
actuated to illuminate the indicator means 15 in synchronization with the
on-operation of the switch 12. The light 16 emitted from the lamp 11
reaches the indicator means 15 through the switch 12, the
light-transmitting tube 13 and the knob 14, and illuminates the image on
the indicator means 15. The light-shielding screen device of the present
invention has excellent bond strength between the first and second light
transmissible substrates and the intermediate layer, and, hence, there is
no danger that the first and second light transmissible substrates peel
off from the intermediate layer even by repeated pushing operations.
In the present invention, the first and second light transmissible
substrates may be made of any film or sheet transparent to light, and the
first light transmissible substrate is the same as or different from the
second light transmissible substrate in their materials. As examples of
the substrates, there may be mentioned films or sheets of synthetic resins
such as acrylate resins, polyester resins, polycarbonate resins and nylon
.
As mentioned above, the intermediate layer of the light-shielding screen
device of the present invention comprises at least one light-shielding
screen portion and a light nontransmissible retaining portion. The
light-shielding screen portion is located in the middle area of the
intermediate layer and the light non-transmissible retaining portion is
located at least in a portion of the remaining area of the intermediate
layer, the portion of the remaining area including the entire outermost
peripheral area of the intermediate layer.
In the present invention, it is preferred that the light non-transmissible
retaining portion be located in an entire portion of the remaining area of
the intermediate layer. However, there may exist between the
light-shielding screen portion and the outermost peripheral area of the
intermediate layer a portion which does not serve to retain the first and
second light transmissible substrate, as far as the entire outermost
peripheral area of the intermediate layer can securely retain on its both
sides the first and second light transmissible substrates, respectively.
In this case, it is required that even the portions which do not serve to
retain the first and second light transmissible substrates, if any, be
also non-transparent to light.
In the present invention, it is preferable that the minimum distance
between the edge of the intermediate layer and the circumference of the
light-shielding screen portion be 1 mm or more.
With respect to the light-shielding screen portion of the intermediate
layer, the light-shielding lines may be arranged to form any pattern
structure. For example, as examples of the pattern structure, there may be
mentioned striped pattern structures, circular pattern structures and
polygonal pattern structures, e.g. triangular, square, rectangular,
rhombic, parallelogramic or honeycomb (hexagonal) pattern structure.
In general, the light-shielding lines each have a width of about 10 to 500
micrometers and are arranged at about 20 to 1,000 micrometers. The ratio
of the width of the light-shielding line to the interval of the
light-shielding lines is generally about 1:1 to 1:20.
In the present invention, the intermediate layer may be one comprising a
photocured resin composition, a photosensitive glass such as Fotoform
glass (manufactured and sold by Corning Glass, U.S.A.) or the like.
As examples of the photocured resin composition, there may be mentioned
those obtained by photocuring a photocurable resin composition. The
photocurable resin composition is defined as those which are capable of
being insolubilized upon exposure to actinic radiation.
The representative examples of the photocurable resin composition are (1) a
radical photopolymerizable composition comprising a compound having a
polymerizable ethylenically unsaturated group and a radical
photopolymerization initiator; (2) an addition photoreactable composition
comprising a polyene compound having a plurality of double bonds, a
polythiol compound having a plurality of thiol groups and a
photosensitizer; (3) a cation photopolymerizable composition comprising a
cation polymerizable compound having an epoxy group or the like and a
cation photopolymerization initiator; and (4) a photocrosslinkable
composition comprising a polymer having a functional group capable of
being photodimerized.
As examples of the compound having a polymerizable ethylenically
unsaturated group contained in the above-mentioned composition (1), there
may be mentioned unsaturated prepolymers such as unsaturated polyesters,
unsaturated polyurethanes, oligomers of an ester-acrylate type,
unsaturated polyimides, unsaturated polyethers, unsaturated polyacrylates
and unsaturated polymethacrylates; unsaturated monomers such as acrylic
acid, acrylic esters, methacrylic acid, methacrylic esters, acrylamide and
its derivatives, methacrylamide and its derivatives, allyl compounds,
maleic acid and esters thereof, fumaric acid and esters thereof; and other
unsaturated compounds such as styrene and its derivatives,
N-vinylcarbazole and N-vinylpyrrolidone. They may be used either alone or
in combination.
Specific examples of the radical photopolymerization initiator contained in
the above-mentioned composition (1) include benzoin, benzoin alkyl ethers,
acetophenone, 2,2'-dimethoxy-2-phenylacetophenone, benzophenone, benzil,
thioxanthone and anthraquinone.
The above-mentioned composition (1) may optionally contain a binder polymer
and a heat polymerization inhibitor. As examples of the binder polymer,
there may be mentioned polymers such as polyvinyl alcohols, polyamides,
polyvinylpyrrolidones, acrylic resins, cellulose derivatives,
polystyrenes, phenol resins and polyesters. As examples of the heat
polymerization inhibitor, there may be mentioned hydroquinone,
p-methoxyphenol, 2,6-di-tert-butyl-p-cresol and the like.
As examples of the polyene compound contained in the above-mentioned
composition (2), there may be mentioned polyurethanes having at their
terminals an ally group, an acryloyl group or a methacryloyl group.
As examples of the polythiol compound and photosensitizer contained in the
above-mentioned composition (2), there may be mentioned pentaerythritol
tetra(.beta.-mercaptopropionate) and benzophenone, respectively.
As examples of the cation polymerizable compound contained in the
above-mentioned composition (3), there may be mentioned epoxy resins and
polyacrylates having at side chains a glycidyl group.
Specific examples of the cation photopolymerization initiator contained in
the above-mentioned composition (3) include compounds which, upon exposure
to light rays, produce Lewis acid salts, e.g. organic diazonium salts,
organic halonium salts and organic sulfonium salts.
As examples of the polymer having a photodimerizable functional group
contained in the above-mentioned composition (4), there may be mentioned
polymers having a cinnamoyl group, a styrylpyridinium group or a
quinolinium group.
The above-mentioned compositions may optionally contain a delustering
agent, a dye and a pigment.
As examples of the delustering agent, there may be mentioned titanium
oxide, mica, calcium carbonate, a powdered glass, a finely divided silica,
aluminum powder, a powdered clay and the like. The amount of the
delustering agent may generally be in the range of 0.1 to 20% by weight,
preferably 0.5 to 10% by weight based on the photocurable resin
composition.
The specific kind of the dye and pigment will be mentioned later.
A representative example of the method of producing the light-shielding
screen device of the present invention will be explained below. A layer of
a photo-curable resin composition is interposed between a first light
transmissible substrate and a negative film. The negative film has a
plurality of portions in which a plurality of lines are arranged to form a
negative image of a predetermined pattern of the light-shielding portion,
and the remaining area of the negative film, i.e., the area corresponding
to the light non-transmissible retaining portion of the intermediate layer
is transparent. The photocurable resin composition layer is exposed to
actinic radiation to form photocured resin composition portions and
uncured resin composition portions. As examples of the actinic light which
may be used in this step, there may be mentioned a solar light or a
radiation emitted from an arc lamp, a mercury lamp, a xenon lamp, an
ultra-violet fluorescent lamp and the like. The negative film is then
removed. The uncured portions are removed by means of a developer. For
example, the uncured portions may be removed by spraying a developer to
wash away the uncured portions; by a brushing method in which the uncured
portions are brushed with a developer bearing brush; a blowing method in
which air is blown upon the uncured portions; a sucking method; or
combined methods of the those mentioned above.
The term "developer" used herein is intended to include a liquid developer
and air. As the liquid developer, there may be mentioned, for example,
water, an alkaline solution such as aqueous sodium hydroxide solution,
aqueous sodium carbonate solution, aqueous sodium borate solution, aqueous
sodium silicate solution, aqueous sodium phosphate solution and aqueous
sodium aluminate solution, an aqueous solution of a surface active agent,
and various organic solvents such as alcohol, 1,1,1-trichloroethane,
tetrachloroethylene, trichloroethylene, tetrachloroethane, toluene and
mixtures thereof.
Subsequently, the remaining photocured resin composition portions are dyed
with a dye to make them non-transparent to light. Alternatively, a dye or
pigment may be incorporated into the photocurable resin composition in
advance and subjected to exposure and development. In this case, it is
necessary to incorporate a dye or pigment into the resin composition in
such an amount that the photosensitivity of the photocurable resin
composition is not remarkably decreased.
As examples of the dye, there may be mentioned a cationic dye, a disperse
dye, an acid dye, a metallized dye, a reactive dye, a direct dye and the
like. The kind of dye to be used may be chosen based on the compatibility
with the photocurable resin composition and on the absorption
characteristics of the dye.
As examples of the pigment, there may be mentioned inorganic and organic
pigments. Of them a pigment having good dispersion properties in the
photocurable resin composition is preferred.
A second light transmissible substrate is attached to the above-mentioned
product on the surface of the remaining photocured portions by an
adhesive. As examples of the adhesive, there may be mentioned nitrile
rubber type adhesives, polyester type adhesives, epoxy type adhesives,
vinyl acetate copolymer type adhesives, synthetic rubber type adhesives,
acrylic type adhesives, chloroprene type adhesives, urethane type
adhesives and silane compound type adhesives. The kind of adhesive to be
used may be chosen according to the materials of the intermediate layer
(photocured resin composition) and the second light transmissible
substrate. The method of attaching the second light transmissible
substrate to the intermediate layer is not critical but the
thermocompression bonding method by means of a laminator is generally
used.
The above-obtained laminate may be cut to obtain a plurality of
light-shielding screen devices. Alternatively, images such as letters or
marks are printed on the surface of either the first light transmissible
substrate or the second light transmissible substrate at the places
corresponding to the light-shielding screen portions. Then the resulting
laminate having images thereon is cut to obtain a plurality of
light-shielding screen devices having an image on the first or second
light transmissible substrate.
In this instance, due to the high bond strength between the first and
second light transmissible substrates and the intermediate layer, there is
no danger that the light transmissible substrate peels off from the
intermediate layer.
As mentioned above, in the light-shielding screen device of the present
invention, at least one light-shielding screen portion is located in the
middle area of the intermediate layer. The light-shielding screen
comprises a plurality of light-shielding lines. The plurality of
light-shielding lines may be arranged at spaced intervals. In this case,
the plurality of light-shielding lines may be horizontal, vertical or
aslant as viewed against the surface of the first light transmissible
substrate. When the light-shielding lines are aslant as viewed against the
surface of the first light transmissible substrate, it is preferable that
the aslanting angle relative to the horizontal direction is 30.degree. to
60.degree..
Further, the light-shielding screen device may have a screen pattern
structure which comprises a first plurality of light-shielding lines
arranged at spaced intervals and a second plurality of crossing
light-shielding lines arranged at spaced intervals which intersect the
first light-shielding lines. In this case, the crossing light-shielding
lines may orthogonally intersect the first light-shielding lines as viewed
against the surface of said first light transmissible substrate.
Furthermore, the light-shielding lines may be left aslant with a slanting
angle of 30.degree. to 60.degree. relative to the horizontal direction as
viewed against the surface of the first light transmissible substrate and
the crossing light-shielding lines may be right aslant with a slanting
angle of 30.degree. to 60.degree. relative to the horizontal direction as
viewed against the surface of the first light transmissible substrate.
As described in the foregoing, the light-shielding screen device of the
present invention has excellent bond strength between the first and second
substrates and the intermediate layer having at least one light-shielding
portion and, hence, can be advantageously used not only for television
receivers, various computer-related displays having a CRT and the like in
which a high mechanical strength of the light-shielding screen device is
not necessarily required but also for indicators of push button type
switches mounted on, e.g., an instrument panel of an automobile in which a
high mechanical strength of the lightshielding device is required.
The present invention will be illustrated in more detail with reference to
the following Examples, which should not be construed to be limiting the
scope of the present invention. The parts are by weight, unless otherwise
indicated. In the Example and the Comparative Example, ADOCOTE
manufactured and sold by TOYO MORTON, Japan was used as a urethane type
adhesive, and a laminator MODEL AL-70 manufactured and sold by Asahi Kasei
Kogyo K.K. was used for bonding the intermediate layer to the second light
transmissible substrate.
EXAMPLE
100 parts of an unsaturated polyester resin having an acid value of 30 mg
KOH/g prepared by effecting condensation polymerization of a mixture of
propylene glycol, diethylene glycol, adipic acid, fumaric acid and
isophthalic acid at a molar ratio of 0.12/0.38/0.24/0.14/0.12, 12 parts of
diethylene glycol dimethacrylate, 30 parts of tetraethylene glycol
dimethacrylate, 12 parts of 2-hydroxyethyl methacrylate, 6 parts of
diacetone acrylamide, 2 parts of benzoin isobutyl ether and 0.03 part of
4-tert-butyl catechol were mixed to obtain a photocurable resin
composition. To this photocurable resin composition was added 5% by weight
of a finely divided silica as a delustering agent to obtain a photocurable
resin composition containing a delu | | |
