Patent Application
20110013868
The present invention relates to an optical waveguide and a flexible optical waveguide that are favorable for visible light guide.
An optical waveguide is a circuit that is formed by providing an optical path on a substrate by utilizing a difference in refractive index of light, thereby guiding an optical signal, in which an optical signal can be guided to a circuit formed on a substrate as similar to a flow of electrons in an electric circuit, by utilizing a difference in refractive index or the like. An optical waveguide having a planar structure is different in structure from an optical fiber in a fiber form.
As stated herein, an optical waveguide and an optical fiber are used for a communication purpose (see, for example, Patent Document 1).
For illuminating a liquid crystal display device of a mobile phone and the like, a light guide plate is used for conducting light emitted from a light source. A light guide plate has a planar form with a substantially plate-like shape, and has a light entering part disposed on one side surface and a polarizing pattern formed over the entire lower surface with plural polarizing pattern devices for reflecting or polarizing light entering on the light entering part toward a light exiting part. The light exiting part is formed over the entire upper surface opposite to the surface having the polarizing pattern formed thereon. Accordingly, the light entering part and the light exiting part are generally adjacent to each other (see, for example, Patent Document 2).
Patent Document 3 proposes an optical cable for illumination containing optical fibers as a purpose other than communication. Furthermore, Patent Document 4 proposes an illumination apparatus containing an optical fiber having a core part transmitting light and a cladding part surrounding the core part, the cladding part containing a dispersoid dispersed thereinside. The dispersoid emits light through photoexcitation with light leaked from the core part, and the light emission is used as an illumination source.
[Patent Document 1] JP-A-2001-74957
[Patent Document 2] Japanese Patent No. 3,151,830
[Patent Document 3] JP-A-2000-147263
[Patent Document 4] JP-A-2004-287067
However, upon using the optical cable for illumination containing optical fibers for illumination, plural cables are necessarily bundled and mounted with an attachment, thereby providing a problem that the assembly is difficultly reduced in size.
The light guide plate has a light exiting part that is not disposed at a particular position, and has a problem that it is difficultly reduced in size.
Accordingly, such an illumination apparatus is demanded that can be easily reduced in size and reduced in thickness and can be formed or the like on a substrate, and furthermore such an illumination apparatus is demanded that can be installed in a small gap in a small-sized electronic apparatus.
In view of the aforementioned problems, an object of the present invention is to provide an optical waveguide for visible light guide that can be easily reduced in size and reduced in thickness, can be formed or the like on a substrate, and can be used for an illumination purpose. Another object of the present invention is to provide a flexible optical waveguide for visible light guide that emits light partly, is flexible to enable use in a bent state, and can be installed in a small gap in a small-sized electronic apparatus.
As a result of earnest investigations made by the inventors, it has been found that the aforementioned problems are solved by disposing a light entering part (light incident part) and a light exiting part (light emission part) of the optical waveguide at particular positions, and more preferably by imparting a particular structure to a particular part between a light entering part (light incident part) and a light exiting part (light emission part) of the optical waveguide.
The present invention includes (1) an optical waveguide for visible light guide containing an optical waveguide layer, at least one light entering part and at least one light exiting part, the light entering part and the light exiting part being disposed not adjacent to each other; (2) the optical waveguide for visible light guide according to the item (1), wherein the optical waveguide layer has a core layer that is partially or entirely covered with a cladding layer, and has at least one selected from a taper structure, a stepwise structure, a relief structure and a discontinuous core structure with the core layer as a structure for emitting light to the light exiting part; and (3) the optical waveguide for visible light guide according to the item (1), which is a flexible optical waveguide in a strip form.
According to the present invention, such an optical waveguide for visible light guide can be provided that can be easily reduced in size and reduced in thickness, can be formed or the like on a substrate, and can be used for an illumination purpose. Furthermore, such a flexible optical waveguide for visible light guide can be provided that emits light partly, is flexible to enable use in a bent state, and can be installed in a small gap in a small-sized electronic apparatus. Moreover, a reflection mirror and the like can be easily produced, and light emission in the vertical direction is enabled.
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The optical waveguide for visible light guide according to the present invention has an optical waveguide layer, at least one light entering part and at least one light exiting part, and the light entering part and the light exiting part are disposed not adjacent to each other. In the optical waveguide for visible light guide according to the present invention, the light entering part and the light exiting part are disposed not adjacent to each other, whereby the light entering part and the light exiting part can be disposed at the desired positions, and light can be emitted partly.
A first preferred embodiment of the present invention is the optical waveguide for visible light guide, in which the optical waveguide layer has a core layer that is partially or entirely covered with a cladding layer, and has at least one selected from a taper structure, a stepwise structure, a relief structure and a discontinuous core structure with the core layer as a structure for emitting light to the light exiting part. Each of these structures with the core layer is a structure for emitting light in a desired shape from a desired position.
A second preferred embodiment of the present invention is the flexile optical waveguide, in which the optical waveguide for visible light guide is in a strip form. Owing to the flexibility and the strip form, the optical waveguide can be used in a bent state and thus can be installed in a small gap in a small-sized electronic apparatus.
The optical waveguide layer in the second embodiment corresponds to the core layer in the core layer/cladding layer of the optical waveguide for communication. The flexible optical waveguide for visible light guide in the second embodiment has a basic structure that has only an optical waveguide layer guiding light without a cladding layer. Owing to the absence of a cladding layer, the flexible optical waveguide for visible light guide can be further reduced in size and reduced in thickness.
In the present invention, the light entering part (light incident part) means an outer surface of a portion of the optical waveguide for visible light guide, on which light is incident from a light source. There are not only a case where the light entering part is on the outer surface of the core layer, but also a case where it is on the outer surface of the cladding layer, in the first embodiment. This is because there is a case where light is incident on the core layer through the cladding layer.
In the present invention, the light exiting part (light emission part) means an outer surface of a portion of the optical waveguide for visible light guide, from which light is emitted. As similar to the light entering part, there are not only a case where the light exiting part is on the outer surface of the core layer, but also a case where it is on the outer surface of the cladding layer, in the first embodiment.
It is preferred that the optical waveguide for visible light guide of the present invention can guide light having a wavelength of from 350 to 800 nm. This is because the optical waveguide is used for illumination.
It is also preferred that the optical waveguide for visible light guide of the present invention is an optical waveguide for guiding light having a wavelength of from 350 to 800 nm, in which the light emission intensity ratio of the maximum peak in a light emission spectrum in a wavelength range of from 420 to 500 nm between the incident light and the emission light has a relationship (incident light peak intensity)/(emission light peak intensity)-1/1 to 1/0.3. This is because excellent visibility for illumination can be obtained when the ratio of the height of the maximum peak is in the range.
It is preferred that the optical waveguide for visible light guide of the present invention has an area of the light exiting part of from 0.0025 to 100 mm2. This is because an illuminance for illumination can be sufficiently secured with the range. It is preferred that in the first embodiment, the core layer has a thickness of from 0.05 to 2.0 mm owing to the same reason.
In the second embodiment of the present invention, the total area of the light exiting part is preferably 70% or less, and more preferably from 20 to 70%, of the total area of the surface that has the maximum surface area of the flexible optical waveguide. According to the structure, the luminance of the light emitted can be increased.
In the second embodiment of the present invention, for emitting light in a desired shape from a desired position, the optical waveguide layer preferably has at least one selected from a stepwise structure, a relief structure and a mesh structure, as a structure for emitting light to the light exiting part. These structures may be formed either inside the optical waveguide layer or at an interface thereof.
It is preferred that the flexible optical waveguide for visible light guide according to the second embodiment of the present invention has the light entering part and the light exiting part that are disposed on the same surface or opposing surfaces of the optical waveguide layer. The case includes a case where the light entering part and the light exiting part are each independently disposed on the upper surface or the lower surface of the optical waveguide layer and a case where the light entering part and the light exiting part are each independently disposed on the side surface of the optical waveguide layer, and the former case is more preferred. The area of the light entering part and the area of the light exiting part can be made larger on the upper surface or the lower surface of the optical waveguide layer than the side surface thereof, thereby increasing the luminance of the light emitted.
In the second embodiment of the present invention, one of the light entering part and the light exiting part may be disposed on the side surface of the optical waveguide layer, and the other may be disposed on the upper surface or the lower surface of the optical waveguide layer. The case includes a case where the light entering part is disposed on the upper surface or the lower surface of the optical waveguide layer whereas the light exiting part is disposed on the side surface of the optical waveguide layer and a case where the light entering part is disposed on the side surface of the optical waveguide layer whereas the light exiting part is disposed on the upper surface or the lower surface of the optical waveguide layer. In the former case, the area of the light entering part can be made larger on the upper surface or the lower surface of the optical waveguide layer than the side surface thereof, thereby increasing the luminance of the light emitted, and in the later case, the area of the light exiting part can be made larger, both of which may be selected arbitrarily depending on the demanded specification and the design of illumination.
In the present invention, The flexible optical waveguide for visible light guide according to the second embodiment is preferably in a strip form, in which the ratio length/width (the ratio of length divided by width) is preferably from 10 to 50,000, and more preferably from 10 to 1,000. The length of the flexible optical waveguide is preferably from 10 to 500 mm, and more preferably from 50 to 200 mm; the width of the flexible optical waveguide is preferably from 0.01 to 5 mm, and more preferably from 0.1 to 5 mm; and the thickness of the flexible optical waveguide is preferably from 10 to 500 μm, and more preferably from 50 to 300 μm. This is because the narrow and thin structure imparts flexibility and enables installation in a small gap in a small-sized electronic apparatus. Furthermore, the optical waveguide may have a structure where at least a part of the light exiting part is bent, whereby the optical waveguide can be installed in a bent small gap. This is also because the luminance of the light can be increased with the narrow structure.
The present invention will be described below with reference to the drawings.
The optical waveguide for visible light guide 1 of the present invention has a structure, in which the core layer 31 that is partially or entirely covered with a cladding layer 40. By covering the core layer 31 with the cladding layer 40, the light can pass through the core layer 31 to irradiate only a necessary portion, and the core layer 31 can have high reliability (for example, heat resistance, moisture resistance and strength).
Structures for emitting light to a light exiting part 20 of an optical waveguide for visible light guide 1 according to the first embodiment of the present invention will be described with reference to
In
In
In
In
The light 3 exits from the light exiting part 20 on the side Surface in
In
In
The optical waveguide for visible light guide 1 that has various illumination patterns can be produced by providing or combining the taper structure, the stepwise structure, the relief structure and/or the discontinuous core structure mentioned above in the light entering part 10 and/or the light exiting part 20 of the core layer 31, and/or the core layer 31 between the light entering part 10 and the light exiting part 20.
In the first embodiment of the present invention, the taper structure, the stepwise structure, the relief structure and/or the discontinuous core structure provided in the optical waveguide for visible light guide 1 can be generally formed by a photolithography method, a stamping method, a pressing method, an imprinting method or a combination of the methods.
The structure of the light entering part 10 of the optical waveguide for visible light guide 1 according to the first embodiment of the present invention is not limited in any way, and not only light may be incident on the cross section on the end of the core in the coaxial direction, but also light may be incident in various directions including the upper surface, the side surface and the lower surface.
The structures where light is incident on the light entering part 10 of the optical waveguide for visible light guide 1 according to the first embodiment of the present invention will be described below with reference to
In
In
The aforementioned structures of the light entering part 10 and the core layer adjacent thereto and the aforementioned structures of the light exiting part 20 and the core layer adjacent thereto may be appropriately combined and installed in the optical waveguide for visible light guide 1, thereby providing the optical waveguide for visible light guide 1 for illumination emitting light 3 with various modes.
The structure of the light entering part 10 of the flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention is not limited in any way, and not only light may be incident on the cross section on the end of the optical waveguide layer in the coaxial direction (i.e., light enters directly into the optical waveguide without a mirror or the like), but also light may be incident in various directions including the upper surface, the side surface and the lower surface.
The structures where light is incident on the light entering part 10 of the flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention will be described below with reference to
In
In
Structures for emitting light to a light exiting part 20 of a flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention will be described with reference to
In the similar manner, steps in the horizontal direction (i.e., the direction toward the side surface) of the optical waveguide layer 30 may form reflection mirrors 60 by each of the steps, and the reflection mirrors 60 may totally constitute a stepwise structure 30a. In this case, light 3 is reflected by each of the reflection mirrors 60 in the horizontal direction (i.e., the direction toward the side surface) to form plural branches of the light 3 in the horizontal direction (i.e., the direction toward the side surface). In this case, the light 3 exits from the light exiting part 20 on the side surface.
As similar to
As similar to
The flexible optical waveguide for visible light guide 1a that has various illumination patterns can be produced by providing or combining the stepwise structure 30a, the relief structure 30b and/or the mesh structure 30c mentioned above in the light entering part 10 and/or the light exiting part 20 of the optical waveguide layer 30, and/or the optical waveguide layer 30 between the light entering part 10 and the light exiting part 20.
In the second embodiment of the present invention, the stepwise structure, the relief structure and/or the mesh structure provided in the flexible optical waveguide for visible light guide 1a can be generally formed by a photolithography method, a stamping method, a pressing method, an imprinting method or a combination of the methods.
The aforementioned structures of the light entering part 10 and the optical waveguide layer adjacent thereto and the aforementioned structures of the light exiting part 20 and the optical waveguide layer adjacent thereto may be appropriately combined and installed in the flexible optical waveguide for visible light guide 1a, thereby providing the flexible optical waveguide for visible light guide 1a for illumination emitting light 3 with various modes.
The material used in the core layer 31 of the optical waveguide for visible light guide 1 according to the first embodiment of the present invention and the optical waveguide layer 30 of the flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention is not particularly limited as far as it is a transparent material and has a refractive index that is higher than the cladding layer in the first embodiment or higher than the air in the second embodiment, and a thermosetting resin, a thermoplastic resin, a photocurable resin and the like may be used, specific examples of which include a (meth)acrylic resin (the (meth)acrylic resin herein means an acrylic resin or a methacrylic resin), a styrene resin, a vinyl resin, an olefin resin, an alicyclic polyolefin resin, a phenol resin, a phenoxy resin, an epoxy resin, a urethane resin, a polyamide resin, a polyester resin, a polyesteramide resin, a polyether resin, a urea resin, a polythioether resin, a polythiourea resin, a silicone resin, a polyetheramide resin, a polyimide resin, a polyamideimide resin and a polycarbonate resin. Two or more kinds of these resins may be used unless transparency is impaired, and monomers constituting the aforementioned resins may be used in combination, such as a (meth)acrylate monomer, a vinyl monomer, a diol compound, a carboxylic acid, a carboxylic anhydride, an amine compound, an isocyanate compound and a silane compound. Among these, a (meth)acrylic resin, a vinyl resin, an olefin resin, an alicyclic polyolefin resin, a phenoxy resin, an epoxy resin, a polythioether resin, a polycarbonate resin, a silicone resin and the like are preferred owing to excellent transparency thereof.
The material used in the cladding layer 40 of the optical waveguide for visible light guide 1 according to the first embodiment of the present invention is not particularly limited as far as it is a material having a refractive index that is lower than the core layer, and may not be necessarily transparent. However, it is preferred for workability that the material is approximately translucent upon subjecting to a cutting operation or the like. The cladding layer 40 that is translucent may exhibit an effect of diffusing light in some cases.
As the material used in the cladding layer 40, a thermosetting resin, a thermoplastic resin, a photocurable resin and the like may be used, specific examples of which include a (meth)acrylic resin, a styrene resin, a vinyl resin, an olefin resin, an alicyclic polyolefin resin, a phenol resin, a phenoxy resin, an epoxy resin, a urethane resin, a polyamide resin, a polyester resin, a polyesteramide resin, a polyether resin, a urea resin, a polythioether resin, a polythiourea resin, a silicone resin, a polyetheramide resin, a polyimide resin, a polyamideimide resin and a polycarbonate resin. Two or more kinds of these resins may be used, and monomers constituting the aforementioned resins may be used in combination, such as a (meth)acrylate monomer, a vinyl monomer, a diol compound, a carboxylic acid, a carboxylic anhydride, an amine compound, an isocyanate compound and a silane compound. Furthermore, an elastomer and/or an inorganic filler may be used depending on necessity for diffusing light and for enhancing toughness of the resin.
The elastomer herein is not particularly limited as far as it is a material having a glass transition temperature that is around or lower than room temperature, and examples thereof include a silicone resin, a (meth)acrylic resin, an ethylene-propylene copolymer, a styrene-(meth)acrylic copolymer, polybutadiene, polyisoprene and a urethane resin.
As the inorganic filler referred herein, a fibrous inorganic filler, a sheet-shaped inorganic filler, a spherical inorganic filler, a fibrous organic filler, a sheet-shaped organic filler and the like may be used. Examples of the fibrous inorganic filler and the sheet-shaped inorganic filler include glass fibers, microglass fibers, pitch carbon fibers, polyacrylonitrile carbon fibers, active carbon fibers, sepiolite fibers, potassium titanate fibers, ceramic fibers, wollastonite fibers, rock wool, and a sheet formed of these materials. Examples of the spherical inorganic filler include silica, alumina, titanium oxide, barium titanate, calcium carbonate, magnesium carbonate, carbon, clay, silicon carbide, talc, aluminum silicate, magnesium silicate, mica, calcium hydroxide and barium sulfate. Examples of the fibrous organic filler and the sheet-shaped organic filler include aramid fibers, a sheet formed of aramid fibers, polyester fibers and a sheet formed of polyester fibers. The fillers may be used solely or in combination of plural kinds thereof.
The optical waveguide for visible light guide 1 according to the first embodiment of the present invention may have, depending on necessity, in addition to the reflection mirror 60 or instead of the reflection mirror, a light reflection layer adjacent to a part of the cladding layer. The flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention may have, depending on necessity, in addition to the reflection mirror 60 or instead of the reflection mirror, a light reflection layer covering at least a part of the optical waveguide layer 30. According to the structure, the traveling direction of the light 3 can be changed, and the light 3 can be branched. As the light reflection layer, a metal may be vapor-deposited on the reflection surface, a reflection film or a metallic foil may be adhered thereto, or a coating material containing a sheet-shaped inorganic filler may be coated thereon. Furthermore, these, may be adhered for serving also reinforcement.
The reflection mirror 60 and the light reflection layer are preferably provided in combination for enhancing the reflection efficiency.
The optical waveguide for visible light guide 1 according to the first embodiment of the present invention may have, depending on necessity, a light scattering layer adjacent to the light exiting part of the optical waveguide for visible light guide. The light scattering layer is formed by providing a diffraction grating or a hemispheric relief as shown in
The flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention may have, depending on necessity, as a structure scattering light adjacent to the light exiting part of the flexible optical waveguide for visible light guide, in addition to the relief structure or the mesh structure or instead of the relief structure or the mesh structure, a light scattering layer formed by adding fine particles having a diameter of from 0.05 to 100 μm, preferably from 0.1 to 5 μm, and particularly preferably from 0.1 to 1.0 μm, to the portion adjacent to the light exiting part of the optical waveguide layer 30.
Examples of the fine particles used include inorganic fine particles, such as titanium oxide, glass beads, magnesia, barium sulfate, silica, calcium carbonate and zirconia oxide, and polymer fine particles, such as polystyrene, polyacrylate, polymethacrylate, polyvinyl acetate, polyurethane, polyurea, polyimide, polyimide, polyester and silicone. The fine particles preferably has a spherical shape. With fine particles having an acicular shape or a sheet-shaped shape, the fine particles may not be suitably irradiated with the incident light, the angles of the scattered light may be biased, and the scattered light may be shielded by the other particles, whereby the intensity of the scattered light may be lowered.
The optical waveguide for visible light guide 1 according to the first embodiment of the present invention may further have, depending on necessity, at least one selected from a diverging lens, a converging lens, a prism and a reflection mirror, adjacent to the light entering part and/or the light exiting part of the optical waveguide for visible light guide. Furthermore, the optical waveguide for visible light guide may have, depending on necessity, at least one selected from a colored layer formed of a colored (resin) film or the like, a color filter, a polarizing filter and a coating layer containing a dye or a pigment, adjacent to the light entering part and/or the light exiting part thereof. The use of a colored film, a color filter or a coating layer containing a dye or a pigment provided adjacent to the light entering part 10 and/or the light exiting part 20 of the optical waveguide for visible light guide 1 can change the light 3 emitted to desired color, and the light 3 can be converted to polarized light by passing through a polarizing filter.
The flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention may have, depending on necessity, at least one selected from a reflection mirror, a colored layer, a diverging lens, a converging lens, a prism and a polarizing filter, in at least a part of the flexible optical waveguide for visible light guide, particularly at a position adjacent to the light entering part and/or the light exiting part or in the light entering part and/or the light exiting part.
The light 3 can be diffused or focused with a diverging lens, a converging lens or the like. The light 3 can be deflected, branched, reflected or the like with a prism, and the light 3 can be reflected with a reflection mirror described in the foregoing.
The diverging lens, the converging lens, the prism and the reflection mirror 60 used in the present invention may be formed by directly cutting or may be formed by a pressing method, a stamping method, an imprinting method, a photolithography method or the like. These may also be formed by adhering to or embedding in the waveguide a diverging lens, a converging lens, a prism or a lens array thereof, which is formed by an injection molding method, a pressing method, a stamping method, an imprinting method, a photolithography method, an ink-jet method, a casting method or the like.
The light 3 having various colors can be emitted by attaching or the like a colored layer formed of a colored (resin) film or the like to the light entering part and/or the light exiting part. Unnecessary reflected light and polarized component can be removed from the light by attaching or the like a polarizing filter to the light entering part and/or the light exiting part.
The flexible optical waveguide for visible light guide 1a according to the second embodiment of the present invention may further have, depending on necessity, for protecting the optical waveguide layer, a protective layer covering at least a part of the optical waveguide layer 30. This is because when the flexible optical waveguide is damaged or the like, the possibility arises that light is leaked from the portion other than the light exiting part. A protective layer having high transparency and high scratch resistance may be disposed at the light entering part or the light exiting part for maintaining the transparency of the light entering part or the light exiting part. The protective layer preferably functions as the light reflection layer, the colored layer, the polarizing filter or the like, for suppressing the thickness of the flexible optical waveguide for visible light guide 1a.
Examples of the material for the protective layer include an organic material, such as polyolefin, polycycloolefin, polyvinyl halide, polystyrene, polyacrylate, polymethacrylate, polyester, liquid crystalline polyester, unsaturated polyester, polyamide, polyimide, polyamideimide, polyesterimide, polyurethane, an epoxy resin, a phenoxy resin, a phenol resin, a urea resin and a silicone resin, and a metallic material, such as gold, silver, copper and aluminum. These material may be used in combination of two or more kinds thereof.
The present invention will be described in more detail with reference to examples below, but is not limited in any way by the examples.
150 parts by mass of propylene glycol monomethyl ether acetate and 30 parts by mass of methyl lactate were weighted in a flask equipped with a stirrer, a condenser, a gas introducing tube, a dropping funnel and a thermometer, and were started to be stirred with nitrogen gas introduced. The liquid temperature was increased to 80° C., and 20 parts by mass of N-cyclohexylmaleimide, 40 parts by mass of dicyclopentadienyl methacrylate, 25 parts by mass of 2-ethylhexyl methacrylate, 15 parts by mass of methacrylic acid and 3 parts by mass of 2,2′-azobis(isobutyronitrile) were added dropwise thereto, followed by stirring continuously at 80° C. for 6 hours, thereby providing a (meth)acrylic polymer P-1 solution (solid content: 36% by mass).
168 parts by mass (solid content: 60 parts by mass) of the P-1 solution (solid content: 36% by mass), 0.03 part by mass of dibutyltin dilaurate and 0.1 part by mass of p-methoxyphenol were weighed in a flask equipped with a stirrer, a condenser, a gas introducing tube, a dropping funnel and a thermometer, and were started to be stirred with the air introduced. The liquid temperature was increased to 60° C., and 7 parts by mass of 2-methacryloyloxyethylisocyanate was added dropwise thereto over 30 minutes, followed by stirring at 60° C. for 4 hours, thereby providing a polymer solution for binder (A) (solid content: 40% by mass).
The result of measurement of the acid value of (A) was 98 mgKOH/g. The acid value was calculated from the amount of a 0.1 mol/L potassium hydroxide aqueous solution that was required for neutralizing P-1. The point where phenolphthalein added as an indicator was changed from colorless to pink color was designated as the neutralization point.
168 parts by mass (solid content: 60 parts by mass) of (A) (solid content: 36% by mass), 20 parts by mass of ethoxylated bisphenol A diacrylate (A-BPE-6, produced by Shin-Nakamura Chemical Co., Ltd.), 20 parts by mass of p-cumylphenoxyethyl acrylate (A-CMP-1E, produced by Shin-Nakamura Chemical Co., Ltd.) and 2 parts by mass of a mixture of 2-(2-oxo-2-phenylacetoxyethoxy)ethyl oxyphenylacetate ester and 2-(2-hydroxyethoxy)ethyl oxyphenylacetate ester (Irgacure 754, produced by Ciba Specialty Chemicals Co., Ltd.) were weighed in a wide mouthed polymer bottle, and stirred with a stirrer under conditions of a temperature of 25° C. and a rotation number of 400 rpm for 6 hours, thereby preparing a resin varnish for forming a core part. Thereafter, it was filtered under pressure with Polyflon Filter having a pore diameter of 2 μm (PF020, produced by Advantech Toyo Co., Ltd.) and a membrane filter having a pore size of 0.5 μm (J050A, produced by Advantech Toyo Co., Ltd.) under conditions of a temperature of 25° C. and a pressure of 0.4 MPa. Subsequently, it was defoamed with a vacuum pump and a bell jar under conditions of a depressurizing degree of 50 mmHg for 15 minutes, thereby providing a resin varnish CO-1 for forming a core part.
Production of Resin Film COF-1 for forming Optical Waveguide Layer or Core Part
The resin varnish CO-1 for forming a core part was coated on an untreated surface of a PET film (A1517, produced by Toyobo Co., Ltd., thickness: 16 μm) with a coating machine (Multi Coater TM-MC, produced by Hirano Tecseed Co., Ltd.) and dried at 100° C. for 20 minutes, to which a releasable PET film (A31, produced by Teijin DuPont Films Japan, Ltd., thickness: 25 μm) as a protective film was then attached, thereby providing a resin film COF-1 for forming an optical waveguide layer or a core part. The thickness of the resin layer was able to control arbitrarily by changing the gap of the coating machine, and it was controlled to provide a thickness of the film after curing of 100 μm in this example.
Preparation of Resin Varnish CL-1 for forming Cladding Layer
168 parts by mass (solid content: 60 parts by mass) of (A) (solid content: 36% by mass), 20 parts by mass of ethoxylated cyclohexanedimethanol diacrylate (A-CHD-4E, produced by Shin-Nakamura Chemical Co., Ltd.), 20 parts by mass of ethoxylated isocyanuric acid triacrylate (A-9300, produced by Shin-Nakamura Chemical Co., Ltd.), 1 part by mass of 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959, produced by Ciba Specialty Chemicals Co., Ltd.) and 1 part by mass of bis(2,4,6-trimethylbenzoyl)phenylphosfine oxide (Irgacure 819, produced by Ciba Specialty Chemicals Co., Ltd.) were weighed in a wide mouthed polymer bottle, and stirred with a stirrer under conditions of a temperature of 25° C. and a rotation number of 400 rpm for 6 hours, thereby preparing a resin varnish for forming a cladding part. Thereafter, it was filtered under pressure with Polyflon Filter having a pore diameter of 2 μm (PF020, produced by Advantech Toyo Co., Ltd.) and a membrane filter having a pore size of 0.5 μm (J050A, produced by Advantech Toyo Co., Ltd.) under conditions of a temperature of 25° C. and a pressure of 0.4 MPa. Subsequently, it was defoamed with a vacuum pump and a bell jar under conditions of a depressurizing degree of 50 mmHg for 15 minutes, thereby providing a resin varnish CL-1 for forming a cladding part.
Production of Resin Film CLF-1 for forming Lower Cladding Layer
The resin varnish CL-1 for forming a cladding layer was coated on an untreated surface of a PET film (A4100, produced by Toyobo Co., Ltd., thickness: 50 μm) in the same manner as the resin film for forming a core layer, thereby providing a resin film CLF-1 for forming a cladding layer. The thickness of the resin layer was able to control arbitrarily by changing the gap of the coating machine, and it was controlled to provide a thickness of the film after curing of 25 μm in this example.
Production of Resin Film CLF-2 for forming Upper Cladding Layer
The resin varnish CL-1 for forming a cladding layer was coated on an untreated surface of a PET film (A1517, produced by Toyobo Co., Ltd., thickness: 16 μm) in the same manner as the resin film for forming a core layer, thereby providing a resin film CLF-1 for forming a cladding layer. The thickness of the resin layer was able to control arbitrarily by changing the gap of the coating machine, and it was controlled to provide a thickness of the film after curing of 70 μm in this example.
Two sheets of the coated film, from each of which the protective film (A31) had been removed, were adhered to each other and laminated under conditions of a pressure of 0.2 MPa, a temperature of 50° C. and a pressurizing time of 30 seconds, with a vacuum pressurizing laminating machine, thereby providing a resin film (CLF-2) having a film thickness of 140 μm for forming an upper cladding.
The resin film CLF-1 for forming a lower cladding layer was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 with an ultraviolet ray exposure machine (MAP-1200-L, produced by Dainippon Screen Mfg. Co., Ltd.), and then the substrate film (A1517) was removed. Separately, the film for forming a core layer was punched out with a die having an arbitrary shape along with the protective film (A31) and the PET film (A1517), thereby preparing a core pattern. The protective film (A31) was removed from the core film thus punched out, which was then attached to the cured CLF-1 film with a vacuum pressurizing laminating machine. Thereafter, the core layer was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 with an ultraviolet ray exposure machine and further subjected to a heat treatment at 80° C. for 10 minutes, and then the substrate film (A1517) was removed.
The resin film CLF-2 for forming an upper cladding layer, from which the protective film (A31) had been removed, was laminated on core part and the lower cladding layer under conditions of a pressure of 0.5 MPa, a temperature of 50° C. and a pressurizing time of 30 seconds, with a vacuum pressurizing laminating machine. The laminated assembly was irradiated with an ultraviolet ray (wavelength; 365 nm) at 2,000 mJ/cm2, and after removing the substrate film (A1517), was subjected to a heat treatment at 120° C. for 1 hour to form an upper cladding layer, thereby providing an optical waveguide for visible light guide. Thereafter, a light entering part and a light exiting part were obtained by cutting with a dicing saw (DAD-341, produced by Disco Corporation), thereby producing an optical waveguide for visible light guide shown in
The resin film CLF-1 for forming a lower cladding layer was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 with an ultraviolet ray exposure machine (MAP-1200-L, produced by Dainippon Screen Mfg. Co., Ltd.), and then the substrate film (A1517) was removed.
Separately, the film for forming a core layer was punched out with a die having an arbitrary shape along with the protective film (A31) and the PET film (A1517), thereby preparing a core pattern. The protective film (A31) was removed from the core film thus punched out, which was then attached to the cured CLF-0.1 film with a vacuum pressurizing laminating machine. Thereafter, the core layer was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 with an ultraviolet ray exposure machine and further subjected to a heat treatment at 80° C. for 10 minutes, and then the substrate film (A1517) was removed. The film was then heated to 120° C., and the light exiting part of the core layer was embossed by a stamping method.
The resin film CLF-2 for forming an upper cladding layer, from which the protective film (A31) had been removed, was laminated on core part and the lower cladding layer under conditions of a pressure of 0.5 MPa, a temperature of 50° C. and a pressurizing time of 30 seconds, with a vacuum pressurizing laminating machine. The laminated assembly was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2, and after removing the substrate film (A1517), was subjected to a heat treatment at 120° C. for 1 hour to form an upper cladding layer, thereby providing an optical waveguide for visible light guide. Thereafter, a light entering part and a light exiting part were obtained by cutting with a dicing saw (DAD-341, produced by Disco Corporation), thereby producing an optical waveguide for visible light guide shown in
Optical waveguides for visible light guide (Examples 3 to 10) shown in
An optical waveguide shown in
All the optical waveguides for visible light guide of Examples 1 to 12 were able to be reduced in size and formed or the like on a substrate, and thus were favorably used for illumination.
The film for forming an optical waveguide layer was punched out with a die having an arbitrary shape along with the protective film (A31) and the PET film (A1517), thereby preparing a core pattern. Thereafter, the film was irradiated with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 with an ultraviolet ray exposure machine with an ultraviolet ray exposure machine (MAP-1200-L, produced by Dainippon Screen Mfg. Co., Ltd.) and further subjected to a heat treatment at 80° C. for 10 minutes. The protective film (A31) and the substrate film (A1517) were removed from the core film punched out, thereby providing a flexible optical waveguide for visible light guide shown in
The protective film (A31) at the light exiting part of the film for forming an optical waveguide was peeled, and a silicone mold having an arbitrary shape formed thereon was pressed onto the light exiting part at a temperature of 60° C. and a pressure of 0.4 MPa for 30 seconds. The optical waveguide layer was irradiated in that state with an ultraviolet ray (wavelength: 365 nm) at 2,000 mJ/cm2 from the side of the PET film with an ultraviolet ray exposure machine and further subjected to a heat treatment at 80° C. for 10 minutes. Thereafter, the silicone mold, the remaining protective film (A31) and the substrate film (A1517) were removed. Thereafter, the optical waveguide was cut out to have a width of 1 mm with the aforementioned dicing saw, thereby producing a flexible optical waveguide for visible light guide shown in
Light emitted from a white LED at the light entering part of the optical waveguide was guided, and the light emission spectrum of the incident light (i.e., the spectrum of the light emitted from the white LED) and the light emission spectrum of the emission light (i.e., the spectrum of the light emitted from the light exiting part) were measured with a multiple photometry system (MCPD-3000, a trade name, produced by Otsuka Electronics Co., Ltd.).
Flexible optical waveguides for visible light guide (Examples 15 and 16) shown in
The light emission areas emitting light were 50 mm2 in Example 15 shown in
All the flexible optical waveguides for visible light guide of Examples 13 to 16 were able to be reduced in size and formed or the like on a substrate, and thus were favorably used for illumination.
The optical waveguide for visible light guide of the present invention has a planar structure, can be reduced in size and increased in density, and can be formed or the like on a substrate, and the flexible optical waveguide for visible light guide of the present invention can be easily reduced in width and thickness, is flexible to enable use in a bent state, and can be installed in a small gap in a small-sized electronic apparatus, which can be favorably applied to illumination and light indication of various kinds of small-sized electronic apparatuses.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-325147 | Dec 2007 | JP | national |
| 2008-002147 | Jan 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/072832 | 12/16/2008 | WO | 00 | 9/14/2010 |
