JP2016091852A - Light transmission body and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light transmission body enabling even light emission, and a luminaire using the light transmission body.SOLUTION: In a light transmission body at least a part of which fine particles are dispersed, the fine particles is hexagonal tubular zinc oxide. The light transmission body comprises a tubular clad material, and a core material stored in the clad material and having a higher refractive index than the clad material, and the fine particles are dispersed to the clad material. The average particular diameter of the fine particle is within a range of a wavelength from visible ray to infrared ray. A luminaire comprises a light source and the light transmission body.SELECTED DRAWING: Figure 2

Description

  The present invention includes, for example, a mobile phone, a car audio, a pachinko machine, a slot machine, a vehicle room, a dog collar, a kitchen step, a traffic sign, a wash basin, a shower, a hot water indicator for a bathtub, a backlight for an OA device, etc. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light transmission body suitable for illumination and a lighting device using the same, and to a device capable of uniform light emission.

  2. Description of the Related Art Conventionally, various optical transmission bodies that include a core and a clad and emit light from at least one end in the length direction from the circumferential direction (side surface) have been proposed. Examples of related techniques include Patent Documents 1 to 4 and Patent Documents 5 and 6. Moreover, patent document 7 is mentioned as a reference technique.

Japanese Patent No. 3974112: Krabe JP 2004-333539 A: Crabe Japanese Patent No. 4194099: Clave Japanese Patent No. 4928760: Clave JP 2006-317844 A: 3M Japanese Patent No. 5341391: 3M International Publication No. 2012/147886: Sakai Chemical Industry

  The optical transmission bodies described in Patent Documents 1 to 4 have already been put into practical use by the applicant, and have received a certain evaluation from the market. However, in recent years, more uniform light emission is required as a further demand from the market. Specifically, there is a demand for an optical transmission body that reduces the luminance change due to the distance from the light source and can obtain uniform light emission from any position. Furthermore, there is a demand for an optical transmission body that suppresses light emission in a specific direction and can obtain uniform light emission from any angle.

  The present invention has been made to solve such problems of the prior art, and an object of the present invention is to provide an optical transmission body capable of uniform light emission and an illumination device using the same. is there.

In order to achieve the above object, an optical transmission body according to the present invention is characterized in that in an optical transmission body in which fine particles are dispersed at least partially, the fine particles are hexagonal plate-like zinc oxide. .
In addition, it is considered that the optical transmission body is composed of a tubular clad material and a core material housed in the clad material and having a higher refractive index than the clad material, and the fine particles are dispersed in the clad material. .
Moreover, the illuminating device by this invention consists of a light source and said optical transmission body.

  According to the present invention, since the fine particles are hexagonal plate-like zinc oxide, sufficient luminance can be obtained not only near the light source but also at a position away from the light source, and the change in luminance due to the distance from the light source is reduced. In particular, when the average particle size of the fine particles is within the wavelength range of the visible light region, light emission is performed not only in the incident direction of light from the light source but also in the direction opposite to the incident direction. As a result, uniform light emission can be obtained from any position and any angle.

It is a partially notched side view which shows the optical transmission body by a present Example. It is an electron micrograph of fine particles used in this example. It is a partially cutaway side view showing an optical transmission body on which a light-transmitting resin coating is formed. It is the schematic which shows the test method of the optical characteristic by an angle. It is a graph which shows the optical characteristic of the length direction in a present Example and a comparative example. It is a graph which shows the optical characteristic of the length direction in a present Example. It is a graph which shows the optical characteristic by the angle in a present Example and a comparative example. It is a graph which shows the optical characteristic by the angle in a present Example.

  The optical transmission body in the present invention is obtained by dispersing fine particles in at least a part of a transparent polymer material. The fine particles may be dispersed in a part of the transparent polymer material or may be dispersed in the whole. The constituent material of the transparent polymer material is not particularly limited and may be anything such as plastic or elastomer. For example, polyethylene resin, polypropylene resin, polyamide resin, polyvinyl chloride, acrylic resin, methacrylic resin, modified acrylic resin, polyurethane resin, polyester resin, polycarbonate resin, silicone resin, acrylonitrile-butadiene-styrene resin, cycloolefin Resin, polystyrene resin, natural rubber, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoride Ethylene-perfluoroalkoxyethylene (PFA), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer , Vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene propylene rubber, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV), vinylidene fluoride-tetrafluoroethylene- Fluoropolymers such as hexafluoropropylene-perfluoromethyl vinyl ether copolymer, polyperfluorobutenyl vinyl ether, TFE-perfluorodimethyldioxolane copolymer, fluorinated alkyl methacrylate copolymer, and fluorinated thermoplastic elastomer Can be mentioned. These can be used alone or in a blend of two or more. In addition to being colorless and transparent, it may be colored and transparent depending on the intended use.

  In particular, the optical transmission body in the present invention is preferably composed of a clad material and a core material housed in the clad material and having a higher refractive index than the clad material. With such an optical transmission body, total reflection of light easily occurs at the interface between the clad material and the core material, and the luminance can be sufficient even at a position considerably away from the light source. In addition, if the core material is amorphous, the transparency can be further improved, so that the optical transmission loss can be reduced. It is also conceivable to form a light-transmitting resin coating on the outer periphery of the cladding material.

  The clad material is not particularly limited as long as it is flexible, such as plastic or elastomer, and can be easily molded. For example, polyethylene, polyamide, polyvinyl chloride, silicone resin, natural rubber, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene-hexafluoride Propylene copolymer, tetrafluoroethylene-perfluoroalkoxyethylene (PFA), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride, vinylidene fluoride-4 fluoro Ethylene copolymer, vinylidene fluoride-propylene hexafluoride copolymer, tetrafluoroethylene propylene rubber, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV), vinylidene fluoride-4 Fluorinated ethylene-propylene hexafluoride-perfluoro Chill vinyl ether copolymer, poly perfluoro butenyl vinyl ether, TFE-perfluoro dimethyl dioxolane copolymer, fluorinated alkyl methacrylate copolymer, and a fluorine-based polymer such as a fluorine-based thermoplastic elastomer. These can be used alone or in a blend of two or more.

  Among the materials constituting the above clad material, for example, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene Copolymer (THV), vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene-perfluoromethyl vinyl ether copolymer, ethylene-tetrafluoroethylene-hexafluoropropylene copolymer, etc. It is preferable because of excellent mechanical properties. In particular, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer (THV) is preferable because it is flexible. In addition, since the adhesiveness with the core material and the light-transmitting resin coating can be further improved, when bending the optical transmission body with a small bending radius or when repeatedly bending the optical transmission body, This is preferable because the core material and the clad material can be partially peeled or the light-transmitting resin coating and the clad material can be prevented from peeling.

  Examples of the constituent material of the core material include acrylic resin, methacrylic resin, polyurethane resin, polyester resin, silicone resin, polystyrene resin, vinyl chloride resin, cycloolefin resin, polypropylene resin, acrylonitrile-butadiene-styrene. A material used as a light-transmitting material such as a transparent grade such as a resin or a polycarbonate resin can be selected. Among these materials, a polymer polyol and a polymer of a hydroxyl group-reactive polyfunctional compound are used as one of the constituent components from the viewpoint of flexibility and aging characteristics under high temperature and high humidity. preferable.

  Examples of the polymer polyol include polyoxyalkylene polyols such as polyoxypropylene polyol, polyethylene glycol and polytetramethylene ether glycol, modified polyoxyalkylene polyols such as urethane-modified polyether polyol and silicone-modified polyether polyol, and polyether ester copolymers. Examples thereof include polyols, polycarbonate-based polyols, and copolymers or mixtures thereof. Among these, polyoxypropylene polyol is preferable because it exhibits excellent emission characteristics even in high temperature and high humidity conditions and in warm water.

  Examples of the hydroxy group-reactive polyfunctional compound include compounds having an N-carbonyl lactam group, halides, compounds having an isocyanate group, and compounds having a functional group derived from an isocyanate group. Examples of the compound having an isocyanate group include an aliphatic polyisocyanate, an alicyclic polyisocyanate, and an aromatic polyisocyanate. Examples of the compound having a functional group derived from an isocyanate group include a blocked isocyanate obtained by blocking an isocyanate with a known method such as lactam, and a compound having an isocyanurate obtained by multiplying an isocyanate group by a known method. These can be used alone or in a blend of two or more. Among these, a compound having an isocyanate group or a compound having a functional group derived from an isocyanate group is preferable because it exhibits excellent side emission characteristics under high temperature and high humidity conditions and in warm water. Of the compounds having an isocyanate group, alicyclic polyisocyanates are more preferred. Of the compounds having a functional group derived from an isocyanate group, those having an isocyanurate bond are more preferred.

  A light-transmitting resin coating may be formed on the outer periphery of the clad material. For example, a flexible methacrylic resin is preferably used as a constituent material of the light-transmitting resin coating. Flexible methacrylic resins include methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, benzyl acrylate, etc. The structure is based on a copolymer with (meth) acrylic acid alkyl ester. For example, methacrylic acid esters other than methyl methacrylate such as ethyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate; vinyl acetate; styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α-methylstyrene. Aromatic vinyl monomers such as vinylnaphthalene; nitriles such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; N-ethylmaleimide and N-cyclohexylmaleimide , N-o-chlorophenylmaleimide, N-tert-butylmaleimide and other maleimide compounds; and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, which are appropriately polymerized, are also conceivable. The flexible methacrylic resin may contain a polyolefin resin. Examples of the polyolefin resin include high-density polyethylene, low-density polyethylene, ethylene-1-octene copolymer, ethylene-acrylic acid copolymer, ethylene-zinc acrylate copolymer, ethylene-acrylic acid ester copolymer, Ethylene-based polymers such as ethylene-methacrylic acid ester copolymer, ethylene-vinyl acetate copolymer, hydrolyzate of ethylene-vinyl acetate copolymer; polypropylene, ethylene-propylene copolymer, propylene-1-butene copolymer Propylene polymers such as polymers; Conjugated diene polymers such as butadiene polymers and isoprene polymers; Hydrogenated products of butadiene polymers, Hydrogenated conjugated diene polymers such as hydrogenated products of isoprene polymers, etc. It is done. Moreover, you may contain another polymer and an additive as needed. Examples of additives that can be included include mineral oil softeners such as paraffinic oils and naphthenic oils for improving fluidity during molding; the purpose is to improve or increase heat resistance, weather resistance, etc. Inorganic fillers such as calcium carbonate, talc, titanium oxide, silica, clay, barium sulfate, magnesium carbonate; inorganic fibers or organic fibers such as glass fibers and carbon fibers for reinforcement; thermal stabilizers; antioxidants; An adhesive; an adhesive; a tackifier; a plasticizer; an antistatic agent; and a foaming agent. About these addition amount, what is necessary is just to set suitably according to the characteristic to require. In addition, various dyes, pigments, fluorescent agents, and the like may be blended within a range in which a sufficient amount of emitted light can be obtained, and the emission color of the optical transmission body may be set to a specific color. About the addition amount of the above additives, it is preferable that the light transmittance in the visible light region when the thickness of the flexible methacrylic resin is 0.25 mm is 80% or more. By doing this, the scattering and absorption of light inside the light-transmitting resin coating can be suppressed, so that transmission loss can be reduced, and when the colored light is emitted by a light source of a specific color, it can be designed. The light of the intended color can be emitted in a clear color. The light transmittance in the visible light region is measured according to JIS-K7105 (1981). Of course, in addition to the flexible methacrylic resin, a polymer material as described above can be used as long as it is transparent.

  The light-transmitting resin coating may have not only a circular shape but also an irregular shape in cross section, and the irregular shape is preferably a shape that can be fixed easily and reliably when placed on a flat surface or the like. Selected. For example, a shape in which the contact area between the disposed portion and the optical transmission body increases, a shape that can be fixed by hooking the optical transmission body on the disposed portion, and the like, specifically, a triangle, a quadrangle, Examples of the shape include a pentagon and a hexagon, and the shape shown in FIG. (In the figure, 1 is an optical transmission body, 2 is a cladding material, 3 is a core material, and 4 is a light-transmitting resin coating.)

  Side emission type optical transmission in which fine particles are dispersed in any or all of the core material, the clad material, and the light-transmitting resin coating, thereby providing a light scattering function and emitting incident light from the circumferential direction (side surface). It can be a body. In particular, it is preferable to disperse the fine particles in the clad material from the viewpoint of the uniformity of light emission.

  In the present invention, hexagonal plate-like zinc oxide is used as the fine particles. Since normal zinc oxide fine particles are manufactured through a pulverization process and a baking process, they are irregular and amorphous. Here, the crystal structure of zinc oxide is a hexagonal wurtzite crystal in which a hexagonal close-packed lattice of zinc and a hexagonal close-packed lattice of oxygen atoms moved vertically by 3/8 are overlapped. Structure. For this reason, for example, those obtained by aging ultrafine zinc oxide particles in an aqueous zinc salt solution as described in Patent Document 7 grow into crystals in a specific hexagonal plate shape. Dispersion of zinc oxide in such a shape makes it difficult for light to be absorbed on the surface of the fine particles, and it is difficult for the brightness to decrease even when the distance from the light source is increased. Will be obtained.

  As the particle diameter of the fine particles, the average particle diameter is preferably in the range of visible to near-infrared wavelengths. In the present invention, the visible to near-infrared wavelength is in the range of 360 to 2500 nm (see JIS-K0210 (2007) and JIS-Z8120 (2001)). In particular, the average particle diameter is preferably within the range of the wavelength of visible light. The wavelength of visible light in the present invention refers to that in the range of 360 to 830 nm (see JIS-Z8120 (2001)). When the particle size of the fine particles is not less than the wavelength of visible light, light scattering becomes a Mie scattering region. The intensity of Mie scattering is maximized when the particle diameter is substantially equal to the wavelength. Therefore, the closer the average particle diameter of the fine particles is to the wavelength in the visible light region, the higher the luminance, which is preferable. In Mie scattering, as the particle size increases, the directivity in the incident direction of light increases, and the side and back do not scatter much. Therefore, by stopping the average particle diameter of the fine particles within the wavelength of near infrared rays, the light can be scattered sufficiently to the side and the back, especially by not exceeding the wavelength range of visible light, at any angle. Therefore, uniform light emission can be obtained. In addition, when the average particle size of the fine particles is less than the wavelength of visible light, the effect of Rayleigh scattering appears and the light emission appears to appear bluish, which is not preferable. Further, when the particle size becomes too small, there arises a problem that uniform dispersion becomes difficult. The average particle diameter can be measured by measuring the fixed direction diameter of a sufficient number (for example, 250 or more) of fine particles in an image magnified by an electron microscope or the like, and determining the average value of the cumulative distribution. In particular, since hexagonal plate-like zinc oxide fine particles obtained by crystal growth as described above can be obtained with a uniform particle size, a sufficiently accurate value can be obtained even in such an actual particle size measurement. Can be obtained.

  Moreover, it is preferable that the fine particles are dispersed at a rate of 0.10 to 0.20 vol% in the portion where the fine particles are dispersed in the optical transmission body. When it is less than 0.10 vol%, sufficient light scattering does not occur, and the overall luminance tends to decrease. On the other hand, if it exceeds 0.20 vol%, light is scattered in the vicinity of the light source, and sufficient luminance may not be obtained at a position away from the light source.

  The optical transmission body in the present invention is manufactured by the following method using the above-described constituent materials, for example. First, the material constituting the clad material is formed into a long and tubular shape by a known method such as extrusion molding. In the case where fine particles are dispersed in the clad material, it is conceivable that the material constituting the clad material and the fine particles are kneaded and then extruded. In a state where the clad material is wound around a bobbin or the like, the clad material is filled at least with a polymer polyol in a fluid state and a hydroxy group-reactive polyfunctional compound. Here, “at least” is sufficient if it contains a polymer of a polymer polyol and a hydroxy group-reactive polyfunctional compound as a constituent component, and it is naturally assumed that other third component is included. Is. It is also conceivable to mix and fill the fine particles in accordance with this time. Further, the polymer polyol and the hydroxy group polyfunctional compound are reacted by, for example, heating to perform a non-fluidization treatment. According to said method, since a core material does not deteriorate by being exposed to the heat | fever at the time of carrying out extrusion coating of the transparent resin, when it is set as an optical transmission body, the characteristic is not deteriorated, and it is preferable. Here, before the mixture of the polymer polyol and the hydroxy group-reactive polyfunctional compound (including fine particles in some cases) in a fluidized state is filled in the clad material, the polymer polyol and the hydroxy group polyfunctional compound are heated before heating. It is conceivable to increase the viscosity by performing treatment. By doing so, the time for non-fluidization treatment can be shortened, and in the case of a side emission type optical transmission body, the dispersion state of the fine particles can be made more uniform.

  Examples of the method for filling the clad material with a mixture of the polymer polyol in a fluid state, the hydroxy group-reactive polyfunctional compound, and the fine particles in the clad material include a method using a vacuum pump and a tube pump, and a method of pressure filling. It is done. As another method, for example, when a clad material is formed into a tube shape by an extrusion molding method, a mixture of a polymer polyol in a fluid state and a hydroxy group polyfunctional compound (optionally containing fine particles) is simultaneously filled. Is also possible. By doing so, it is possible to continuously manufacture a long optical transmission body.

  In forming the light-transmitting resin coating, for example, after the light-transmitting resin is extrusion-coated using an extrusion mold designed to have a desired cross-sectional shape on the outer periphery of the clad material formed into a tube shape. In addition, the polymer polyol in a fluid state and a hydroxy group-reactive polyfunctional compound may be filled and non-fluidized, or the polymer polyol and the hydroxy group-reactive polyfunctional compound in a fluid state in the clad material first. It is also conceivable that the light-transmitting resin coating is formed by extrusion coating. However, when forming a light-transmitting resin coating later, care must be taken so that the core material is not altered by the heat of extrusion coating. When the light-transmitting resin coating is formed later, it can be straightened even if a bending gusset is attached during the non-fluidization treatment of the core material.

  Regarding the method for forming the core material, depending on the material type of the core material, the core material can be formed simply by extruding the core material. In that case, after extruding the core material, a method of sequentially extruding the clad material and the light transmissive resin coating on the outer periphery of the core material, the core material, the clad material and the light transmissive resin coating are simultaneously extruded in any combination. Various methods such as a molding method can be used.

  In addition to the method of forming the light-transmitting resin coating on the outer periphery of the clad material by extrusion coating, a method of covering the outer periphery of the clad material with a light-transmitting resin coating previously formed into a tube shape, etc. It is done. However, in this case, it is necessary to make the clad material and the light-transmitting resin coating firmly adhere to each other so that there is no peeling portion.

  In the case of an optical transmission body having an arbitrary shape that does not have a structure composed of a core material and a clad material, the polymer material may be formed into a desired shape by a technique such as extrusion or injection molding as appropriate.

  In the present invention, it is also conceivable that a light source is provided on at least one end of the above-mentioned optical transmission body to form an illumination device. As the light source, a conventionally known light emitting element such as an LED (light emitting diode) or an LD (laser diode) can be used. Further, the light emission color and the number of installed light sources are not particularly limited. For example, the light emission color can be appropriately selected from red, blue, green, yellow, orange, white, etc. LEDs, or a plurality of LEDs can be selected. By combining them, various colors can be obtained and the amount of light can be increased.

  When a side-emission type optical transmission body that emits incident light from the circumferential direction (side surface) is used as the optical transmission body, it is also possible to arrange light sources not only at one end of the optical transmission body but also at both ends. It is done. By doing so, it is possible to obtain light emission with higher brightness, and by using light sources of different emission colors at the respective ends, it is possible to emit light while gradually changing the color in the length direction of the illumination device. A variety of decorative expressions are possible.

  Below, with reference to FIG. 1, the Example regarding the optical transmission body of this invention, a comparative example, and a reference example are demonstrated collectively.

Example 1
As a material constituting the core material 3, polyoxypropylene triol and polyoxypropylene diol are used as the polymer polyol, and hexamethylene diisocyanate is used as the hydroxy group-reactive polyfunctional compound. Further, as a material constituting the clad material 2, a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer is used. As fine particles, hexagonal plate-like zinc oxide having an average particle diameter of 500 nm is used. The fine particles are kneaded with the material of the clad material 2 so as to be 0.16 vol%, and then extruded to obtain a tube-shaped clad material 2 having a diameter of 5.0 mm. In a state where the clad material 2 is wound around a bobbin having a diameter of 300 mm, the clad material 2 is mixed and filled with the material constituting the core material 3 and heated at 100 ° C. so that the core material 3 is subjected to a non-fluidization treatment. Apply. Thus, since the core material 3 and the clad material 2 are formed from the inside, the both ends were cut, and the optical transmission body 1 was obtained.

(Example 2)
About the said microparticles | fine-particles, the optical transmission body 1 was obtained like the said Example 1 except having used the hexagonal plate-shaped zinc oxide with an average particle diameter of 1000 nm.

(Example 3)
The light transmission body 1 was obtained in the same manner as in Example 1 except that the fine particles were changed to 0.036 wt%.

Example 4
About the said microparticles | fine-particles, the optical transmission body 1 was obtained like the said Example 3 except having used the hexagonal plate-shaped zinc oxide with an average particle diameter of 300 nm.

(Comparative Example 1)
About the said microparticles | fine-particles, the optical transmission body 1 was obtained like the said Example 1 except having used the amorphous zinc oxide with an average particle diameter of 260 nm.

(Comparative Example 2)
An optical transmission member 1 was obtained in the same manner as in Example 1 except that the above fine particles were not used.

  Regarding the portion of the clad material 2 of the optical transmission body 1 according to Example 2, particularly, the portion where fine particles are present was photographed 12000 times with an electron microscope. The image is shown in FIG. The hexagonal shape seen in the vicinity of the center of the image is the fine particles (hexagonal plate-like zinc oxide) used in this example.

  Here, in order to evaluate the characteristics of the edge-emitting optical transmission body according to this example, the following tests were performed.

(Optical characteristics in the length direction)
The luminance of the side surface was measured by arranging 1000 mm of each sample in a straight line. A white LED as a light source was used as the origin, and the side luminance at a predetermined position was measured with an illuminometer from there to perform comparative verification. The results of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are shown in FIG. 5, and the results of Example 3 and Example 4 are shown in FIG.
(Optical characteristics by angle)
Each sample 1000 mm was arranged in a straight line, and the luminance was measured at a predetermined angle. As shown in FIG. 3, the white LED as the light source 5 is set as the origin, the center of the cross section of the optical transmission body 1 at a position of 100 mm and a position of 400 mm is taken as the measurement point, and 30 degrees from the line connecting the origin and the measurement point. Synchrotron radiation at angles of 60, 90, 120 and 150 degrees was measured with a spectroradiometer. Regarding the result of this test, the luminance at 90 degrees of each sample is used as a reference, and the luminance change at each angle is obtained by dividing the luminance at 30 degrees, 60 degrees, 120 degrees and 150 degrees by the luminance value at 90 degrees. We compared and verified the rate. This test is conducted for Example 1, Comparative Example 1 and Comparative Example 2. FIG. 7 shows the test results at a position 100 mm from the origin, and FIG. 8 shows the test results at a position 400 mm from the origin.

  From these test results, the following was found. First, it was confirmed that the light transmission body according to the present example can obtain sufficient luminance not only near the light source but also at a position away from the light source, and the change in luminance due to the distance from the light source is small. Further, it was confirmed that light was emitted not only in the incident direction of light from the light source but also in the direction opposite to the incident direction. That is, the optical transmission body according to the present example can obtain uniform light emission from any position and any angle.

  On the other hand, in Comparative Example 1 using amorphous zinc oxide fine particles, although absolute luminance was obtained, it was clear that the light emitted strongly in the vicinity of the light source and became darker as it moved away from the light source. There was no change in luminance due to the distance from the light source. In Comparative Example 2 in which the fine particles were not dispersed, the luminance was low as a whole, and it became darker as the distance from the light source increased, and it could not be said that the change in luminance due to the distance from the light source was small.

  Further, when Examples 3 and 4 are compared, Example 4 with a particle size of 300 nm has a smaller change in luminance depending on the distance from the light source, but the overall luminance is higher than that of Example 3 with a particle size of 500 nm. It tended to be low.

  As described in detail above, according to the optical transmission body of the present invention, uniform light emission can be obtained from any position and any angle. Therefore, this optical transmission body is a mobile phone, digital camera, wristwatch, car audio, car navigation, pachinko machine, slot machine, vending machine, vehicle interior / exterior, dog collar, decoration, kitchen, traffic sign, washstand, shower・ Bath bath temperature indicator ・ OA equipment ・ Home appliances ・ Optical equipment ・ Various building materials ・ Stairs ・ Handrails ・ Train homes ・ Outdoor signboards etc. Illumination and lighting, LCD display backlight etc. be able to. Moreover, a light source can be combined with this optical transmission body, and it can be used for various illuminations and illumination facilities as an illumination device.

DESCRIPTION OF SYMBOLS 1 Optical transmission body 2 Cladding material 3 Core material 4 Optically transparent resin coating 5 Light source

(Example 3)
The light transmission body 1 was obtained in the same manner as in Example 1 except that the fine particles were changed to 0.036 vol %.

Claims (3)

An optical transmission body in which fine particles are dispersed at least in part, wherein the fine particles are hexagonal plate-shaped zinc oxide. The optical transmission body includes a tubular clad material and a core material housed in the clad material and having a higher refractive index than the clad material, wherein the fine particles are dispersed in the clad material. Item 5. The optical transmission body according to Item 1. An illumination device comprising a light source and the optical transmission body according to claim 1.