JPWO2012046754A1 - Optical sheet - Google Patents

Abstract

The present invention proposes an optical sheet that has desired optical characteristics, can reduce the number of optical sheets used in an optical module, and can reduce optical loss. The optical sheet 11 according to an embodiment of the present invention includes, for example, first and second surfaces (12 and 13). In the optical sheet (11) having at least two layers, at least one surface (12 or 13) or the interface (14a or 15a) is an optical element surface, and at least one layer is a light diffusion layer (17a or 17b).

Description

  The present invention relates to an optical sheet used for an optical module.

  More specifically, the optical characteristics such as the direction of light emitted from the light source of a light emitting module represented by a cold cathode tube, LED, organic or inorganic electroluminescence illuminant, and uniformity of luminance distribution are changed to desired optical characteristics, and the display The present invention relates to an optical sheet used for various optical modules having an information display unit typified by an electric signboard.

  More specifically, the present invention relates to an optical sheet having at least one optical element surface used for an optical module and a light diffusion layer.

  2. Description of the Related Art Conventionally, in an optical module, an optical sheet, for example, a layer having an optical element surface and a light diffusing layer are provided for the purpose of making the direction of light emitted from a light source and uniformity of luminance distribution desired optical characteristics. It is well known to use.

  For example, a surface light source device (optical module) uses a layer (prism sheet) having two optical element surfaces, and the prism apex angle of these prism sheets and the direction of the ridge line of the prism are defined. It has been proposed to increase the brightness. In addition, it has been proposed to achieve uniform luminance distribution by using a light diffusion layer (light diffusion sheet) and a prism sheet superimposed on the optical module. (For example, see Patent Document 1)

  However, the optical sheet superposed body proposed in the above-mentioned patent is a superposed body in which a sheet having an optical element surface and a light diffusing sheet are combined, and the optical by absorption of light when light passes through each sheet. Due to the loss, the luminance of the information display unit is reduced when the optical module is assembled. In addition, it is difficult to reduce the thickness of the optical module. Furthermore, there is room for improvement in the direction of light emitted from the light source and the uniformity of the luminance distribution.

  In the conventional technology, for example, when a sheet to be used is made thin in order to reduce optical loss, it is difficult to form the sheet, and variations in optical characteristics due to the influence of thickness unevenness are likely to occur. Further, when thin sheets are used in an overlapping manner, the operation becomes difficult when the optical module is assembled.

JP-A-8-271894

  The problem to be solved by the present invention is that, in an optical sheet used for an optical module, the direction of light emitted from a light source and the uniformity of luminance distribution, that is, light diffusibility can be easily made desired optical characteristics, and It is to reduce the number of optical sheets used and reduce optical loss. Another object of the present invention is to achieve a reduction in the thickness of the optical module and facilitate the assembly of the optical module by using the optical sheet of the present invention.

  In order to achieve the above object, the present invention provides an optical sheet comprising at least two layers, the first and second surfaces, wherein at least one surface or interface is an optical element surface, and at least one layer. Is an optical sheet characterized by being a light diffusion layer.

  Another aspect of the present invention is an optical sheet, wherein the light diffusion layer has the optical element surface.

  In another aspect of the present invention, at least one of the first and second surfaces has the optical element surface.

  Another aspect of the present invention is an optical sheet in which at least one of the first and second surfaces has the optical element surface, and the optical diffusion surface has the optical element surface. .

  Another aspect of the present invention is an optical sheet having two or more optical element surfaces.

  Another embodiment of the present invention is an optical sheet characterized in that both the first and second surfaces have the optical element surface.

  Another aspect of the present invention is an optical sheet including the light diffusion layer having the first surface as the optical element surface and a light transmission layer.

  According to another aspect of the present invention, there is provided a first light diffusion layer having the first surface as a first optical element surface, and a second light source having the same or different first surface as the first optical element surface. An optical sheet comprising: a second light diffusion layer as a second optical element surface; and a light transmission layer sandwiched between the first light diffusion layer and the second light diffusion layer.

  In another aspect of the present invention, at least one of the interface between the first light diffusion layer and the light transmission layer and the interface between the second light diffusion layer and the light transmission layer is the first light diffusion layer. It is an optical sheet characterized by having a third optical element surface that is the same as or different from one of the one optical element surface and the second optical element surface.

  Another aspect of the present invention is an optical sheet characterized in that the first optical element surface, the second optical element surface, and the third optical element surface have the same shape parallel to each other. is there.

  Another aspect of the present invention is an optical sheet characterized in that the first light diffusion layer and the second light diffusion layer have different refractive indexes from the light transmission layer.

  Another aspect of the present invention is an optical sheet characterized in that the first light diffusion layer and the second light diffusion layer have a refractive index greater than that of the light transmission layer.

  Another embodiment of the present invention includes a first light transmission layer having the first surface as a first optical element surface, the light diffusion layer, and a second light transmission layer, The one light transmission layer has an interface with the light diffusion layer as a second optical element surface that is the same as or different from the first optical element surface, and the second light transmission layer includes the light diffusion layer. Is a third optical element surface that is the same as or different from one of the first optical element surface and the second optical element surface.

  According to another aspect of the present invention, there is provided a first light transmission layer having the first surface as a first optical element surface, the light diffusion layer, and the second surface as the first optical element. A second light transmitting layer having the same or different surface as the second optical element surface, wherein the first light transmitting layer has an interface with the light diffusion layer as the first optical element surface and the second optical element surface. A third optical element surface that is the same as or different from any one of the second optical element surfaces, and the second light transmission layer has an interface with the light diffusion layer through the first optical element surface to An optical sheet having a fourth optical element surface that is the same as or different from any one of the third optical element surfaces.

  In another aspect of the present invention, the first optical element surface, the second optical element surface, the third optical element surface, and the fourth optical element surface have the same shape that are parallel to each other. An optical sheet characterized by the above.

  Another aspect of the present invention is an optical sheet characterized in that a refractive index of the first light transmission layer and the second light transmission layer is different from a refractive index of the light diffusion layer. .

  According to another aspect of the present invention, there is provided an optical sheet characterized in that the first light transmission layer and the second light transmission layer have a refractive index larger than that of the light diffusion layer.

  Another aspect of the present invention is the optical sheet, wherein the second light transmission layer includes a plurality of layers, and the refractive index of the plurality of layers is increased toward the outer layer.

  According to the present invention, in the optical sheet having the first and second surfaces and having at least two layers, at least one surface or interface is an optical element surface, and at least one layer is a light diffusion layer. By applying the optical sheet characterized by the above to the optical module, the uniformity of the direction of light emitted from the light source and the luminance distribution is made to the desired optical characteristics, and the number of optical sheets used in the optical module is reduced, Optical loss can be reduced. Furthermore, the optical module can be thinned and the optical module can be easily assembled.

FIG. 1 is a partial cross-sectional view of a conventional optical sheet superimposed body. FIG. 2 is a partial cross-sectional view of the first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of the second embodiment of the present invention. FIG. 4 is a partial cross-sectional view of a third embodiment of the present invention. FIG. 5 is a partial cross-sectional view of the fourth embodiment of the present invention. FIG. 6 is a partial cross-sectional view of the fifth embodiment. FIG. 7 is a partial cross-sectional view of the sixth embodiment. FIG. 8 is a partial cross-sectional view of the seventh embodiment of the present invention. FIG. 9 is a partial sectional view of an eighth embodiment of the present invention. FIG. 10 is a partial cross-sectional view of the ninth embodiment of the present invention. FIG. 11 is a partial sectional view of a tenth embodiment of the present invention. FIG. 12 is a partial sectional view of the eleventh embodiment of the present invention. FIG. 13 is a partial sectional view of a twelfth embodiment of the present invention. FIG. 14 is a partial sectional view of a thirteenth embodiment of the present invention. FIG. 15 is a partial sectional view of the fourteenth embodiment of the present invention.

  First, before describing an embodiment of an optical sheet of the present invention, a conventional optical sheet superimposed body will be described.

  FIG. 1 is a partial cross-sectional view of an optical sheet superimposed body 1 in which a transparent resin layer 2 having an optical element surface and a light diffusing layer 3 according to the prior art are combined. In the prior art optical sheet superposed body 1, the transparent resin layer 2 and the light diffusion layer 3 are not integrated, in other words, have a surface other than the first and second surfaces. An optical module using such an optical sheet superimposed body 1 is a transparent resin that diffuses when light emitted from a light source (not shown) passes through a light diffusion sheet having a light diffusion layer 3 and has an optical element surface. By directing light in a desired direction when passing through the layer 2, information on the optical module is provided to the observer. In such an optical sheet superposed body 1, the normal light diffusing layer 3 and the transparent resin layer 2 having the optical element surface are separately produced, and are superposed on each other when the optical module is assembled.

  Moreover, the transparent resin layer 2 having such an optical element surface is produced by a method such as heat-press molding a sheet containing a transparent resin into a mold having an optical element shape.

  Usually, the position of the light source in the optical module is located on the side opposite to the information display surface of the optical module, that is, in the lower part of the light diffusion layer in FIG. Moreover, in another form, the light source of an optical module is located in the side part of the optical sheet superimposed body 1, for example.

  Next, an embodiment of the optical sheet of the present invention will be described below with reference to the drawings.

  In the present invention, the first and second surfaces are, for example, the upper surface 12 and the lower surface 13 shown in the partial sectional view of FIG.

  The optical sheet in the present invention refers to various optical modules having an information display unit represented by a display or an electric signboard, and the desired optical characteristics such as the direction of light emitted from the light source of the light emitting module and the uniformity of luminance distribution. It is a sheet used to make it.

  The interface in the present invention is a layer-to-layer boundary that can be distinguished from each other in the optical sheet of the present invention. For example, in FIG. 2, the interface 14 is a boundary between the light transmission layer 16 a and the light diffusion layer 17.

  In the present invention, the optical element surface is a surface on which a desired shape is formed, and is a surface that makes the direction of light emitted from a light source, uniformity of luminance distribution, and the like desired optical characteristics. The optical element surface in the present invention is provided on the first surface, the second surface or the interface.

  In the present invention, the optical element is a desired shape formed on the optical element surface.

  In the present invention, the light diffusion layer is a layer in which light emitted from a light source and transmitted is diffused.

  In the present invention, the light transmission layer is a layer through which light emitted from a light source and transmitted is transmitted.

  The optical sheet of the present invention has a multilayer structure of two or more layers.

  On the optical element surface in the present invention, optical elements represented by a prism shape, a lens shape, and a light scattering uneven shape are formed. In addition, as an optical element for forming the optical element surface of the present invention, a unit shape corresponding to the design of the optical module to be used is adopted in order to obtain desired optical characteristics, and a single unit shape or a plurality of unit shapes are used. They can be combined and formed on the optical element surface.

  The unit shape of the optical element is, for example, a V-shaped linear prism, a U-shaped linear prism, a triangular pyramid prism, a quadrangular pyramid prism, a semi-cylindrical lens, a convex lens, a concave lens, a Fresnel lens, and a light scattering uneven shape. The Such an optical element may be formed on the entire surface of the optical element surface or a part thereof. That is, the optical element surface in the present invention may have an optical element.

  In the present invention, the prism shape is a polyhedral shape having two or more substantially flat surfaces, and is a shape capable of dispersing, refracting, and totally reflecting light.

  In the present invention, the lens shape is a shape having a curved surface typified by a spherical surface, and is a shape capable of diffracting and converging light by refracting light.

  As the shapes of the convex lens and the concave lens, either a spherical lens, an aspheric lens, or a combination thereof can be applied.

  The light-scattering uneven shape on the optical element surface in the present invention is an uneven shape capable of scattering light, with an average roughness (Ra) of the optical element surface being 0.1 μm or more.

  If the average roughness (Ra) of the light scattering uneven surface is 0.1 μm or more, preferably 0.2 μm or more, more preferably 0.5 μm or more, the direction of light and the uniformity of luminance distribution Is preferable because it is easy to express. Further, if the average roughness (Ra) of the surface is 5 μm or less, preferably 3 μm or less, more preferably 2 μm or less, the optical loss is reduced, which is preferable.

  In the present invention, the smooth surface is a surface having an average roughness (Ra) of the surface or interface of less than 0.1 μm.

  The size of the concavo-convex shape of the surface and the average roughness (Ra) of the surface can be measured according to JIS B0601.

  In the optical sheet 11 of the present invention, by having the optical element surface, the direction of the light emitted from the light source and the uniformity of the luminance distribution can be made into desired optical characteristics, and the information of the optical module can be further improved. It can be clearly displayed.

  In the optical sheet 11 of the present invention, the method of forming the optical element surface on the surface or interface of the layer is as follows: 1) Prepare a roll-shaped mold having a shape obtained by inverting the shape of the desired optical element on the peripheral surface; A method in which a molten transparent organic medium or transparent inorganic medium is continuously supplied onto a mold by an extrusion method, the shape of a desired optical element is cooled after molding, and peeled off from a roll mold, 2) desired Prepare a roll-shaped mold that has a mold with an inverted shape of the optical element on the peripheral surface, heat the roll-shaped mold, and continuously roll a sheet of transparent organic medium or transparent inorganic medium on the roll-shaped mold Supplying, cooling after transferring the shape of the desired optical element, and obtaining by peeling from the roll-shaped mold, 3) preparing a mold having a shape reversed to the shape of the desired element, heating the mold, Press the mold on the sheet of transparent organic medium or transparent inorganic medium, 4) A method of transferring the shape of the desired optical element to the sheet, cooling it, and peeling it off from the mold. 4) Using an ultraviolet curable resin, applying the ultraviolet curable resin to the mold of the desired optical element shape, A method obtained by irradiating ultraviolet rays, 5) a method of forming an optical element on a sheet of a transparent organic medium or a transparent inorganic medium by a printing method, and 6) a direct cutting method on the surface of the sheet of the transparent organic medium or transparent inorganic medium. In order to accurately transfer the shape of a desired element onto an optical sheet, any one of methods 1) to 4) is preferable. In order to obtain the optical sheet of the present invention continuously and with stable performance, any one of methods 1) to 4) is preferable.

  In the present invention, the term “transparent” means that the total light transmittance is 30% or more. The total light transmittance is measured using an A light source based on JIS K7105.

  In the present invention, when a transparent organic medium and a transparent inorganic medium are employed as the base material of the light transmission layer 16 or the light diffusion layer 17, the total light transmittance of the transparent organic medium and the transparent inorganic medium is 30% or more, more preferably. Is 50% or more, and more preferably 70% or more. When the total light transmittance of the transparent organic medium and the transparent inorganic medium is large, the optical loss is preferably small.

  In the optical sheet 11 of the present invention, the transparent organic medium or the transparent inorganic medium constituting the light transmission layer 16 is a (meth) acrylic resin, a polycarbonate resin, a polyester resin, a polystyrene resin, a polyvinyl chloride resin, a fluorine resin, a polyolefin resin, Cellulose acetate resin, silicone resin, polyamide resin, epoxy resin, polyacrylonitrile resin, polyurethane resin and glass can be employed.

  In particular, a (meth) acrylic resin, a polycarbonate resin, a polyester resin, a polyvinyl chloride resin, and a fluororesin are preferable because they are excellent in transparency, weather resistance, workability, and dimensional stability. Moreover, when forming the layer which has an optical element surface, since the moldability of an optical element and the softness | flexibility of a sheet | seat are excellent, these resin can be used suitably.

  In the optical sheet 11 of the present invention, when glass is used for the light transmission layer 16, the transparency, weather resistance, dimensional stability, chemical resistance and heat resistance are excellent.

  In the optical sheet 11 of the present invention, when glass is used for the light transmission layer 16, for example, a mold having a shape obtained by inverting the shape of a desired optical element is prepared, and the mold is heated to 300 ° C. or higher to form glass. Press, transfer the shape of the desired optical element, cool, peel off from the mold, and apply the optical sheet by a method described later, for example, a method of applying a light diffusion layer containing an ultraviolet curable resin to a glass sheet and laminating it. Can be obtained.

  In the optical sheet 11 of the present invention, the light transmission layer 16 can contain various additives such as a light stabilizer, a dye, a pigment, an antistatic agent, a plasticizer, a dispersant, and a filler.

  In the optical sheet 11 of the present invention, the light transmission layer may be two or more layers. When there are two or more light transmissive layers, each light transmissive layer may have the same composition or a different composition. When each light transmission layer has the same composition, for example, the type and amount of the additive, the molecular weight of the resin, and the layer thickness may be different from each other.

  In the optical sheet 11 of the present invention, the transparent organic medium or transparent inorganic medium constituting the light diffusion layer 17 is a (meth) acrylic resin, polycarbonate resin, polyester resin, polystyrene resin, polyvinyl chloride resin, fluororesin, polyolefin resin, Cellulose acetate resin, silicone resin, polyamide resin, epoxy resin, polyacrylonitrile resin, polyurethane resin, and glass can be employed.

  In particular, (meth) acrylic resin, polycarbonate resin, polyester resin, polyvinyl chloride resin, and fluororesin are excellent in transparency, weather resistance, processability of the optical sheet, and dimensional stability of the optical element. Further, these resins are excellent in dispersibility in the layer of fine particles added for the purpose of diffusing light transmitted through the optical sheet and flexibility of the sheet, and therefore can be suitably used in the present invention.

  In the optical sheet 11 of the present invention, an ultraviolet curable resin can be adopted as the transparent organic medium or the transparent inorganic medium constituting the light diffusion layer 17.

  In the case of using an ultraviolet curable resin in the optical sheet 11 of the present invention, for example, in the configuration of two or more layers as shown in FIG. 9, the ultraviolet curable resin is applied on the light transmission layer 16a having the optical element surface, and ultraviolet rays are applied. By irradiating, the light transmission layer 16a having the optical element surface and the light diffusion layer 17 are integrated. Since the optical sheet produced in this way does not need to be peeled off from the mold, it has an excellent feature that the optical element is not deformed when peeled off from the mold and adhesion between layers is good.

  In the optical sheet 11 of the present invention, the transparent organic medium or transparent inorganic medium constituting the light diffusion layer 17 includes various additives such as a light stabilizer, a dye, a pigment, an antistatic agent, a plasticizer, a dispersant, and a filler. be able to.

  The light diffusion layer 17 of the optical sheet 11 of the present invention is preferably made of a transparent organic medium or a transparent inorganic medium containing fine particles.

  In the present invention, the fine particles mean particles having an average particle diameter of 10 to 1000 nm. By using fine particles of this size, desired light diffusion occurs in the light diffusion layer.

  The fine particles used in the present invention are preferably a resin or an inorganic substance.

  In particular, the fine particles are melamine resin, (meth) acrylic resin, urethane resin, styrene resin, polyolefin resin and fluororesin resin, and sodium oxide, calcium oxide, aluminum oxide, bismuth oxide, cerium oxide, copper oxide, In the light diffusion layer 17, information on the optical module is an inorganic substance that is one of silicon (silica), tin oxide, yttrium oxide, zinc oxide, titanium oxide, zirconium oxide, glass, quartz, diamond, sapphire, and talc. This is preferable because desired light diffusion can be caused during display and optical loss can be reduced.

  The fine particles can be suitably used regardless of whether they have a single composition or a plurality of compositions. For example, fine particles having a structure in which silica is coated on a melamine resin have high light diffusion performance and can be suitably used.

  Further, the fine particles are silica or resin fine particles having a hollow structure, that is, fine particles containing air inside have a structure having a refractive index difference in the fine particles. be able to.

  Examples of the fine particles that can be used in the present invention include, for example, Nippon Shokubai Co., Ltd. trade name poster, Seahoster and Soliostar, Nissan Chemical Industries, Ltd. trade name Opt beads, Negami Kogyo Co., Ltd. trade name Art Pearl, Dainichi Seika Product name: Dymic beads, manufactured by Gantz Kasei Co., Ltd. Product name: Gantz Pearl, manufactured by JGC Catalysts & Chemicals Co., Ltd. Product name: Surria, manufactured by Sekisui Chemicals Co., Ltd. Is mentioned.

  The shape of the fine particles is not particularly limited, and examples thereof include a spherical shape, a substantially spherical shape, a spheroid shape, a cubic shape, a needle shape, a rod shape, a plate shape, and a scale shape. In particular, in order to obtain a desired light diffusion performance, it is easy to disperse the fine particles in the light diffusion layer, and since light diffusion in the light diffusion layer occurs uniformly, a spherical shape or a substantially spherical shape is preferable.

  The average particle size of the fine particles is preferably 10 to 1000 nm, more preferably 10 to 100 nm. When the average particle size of the fine particles is 10 nm or more, the light diffusion performance is hardly lowered. Further, when the average particle size of the fine particles is 1000 nm or less, the fine particles can be easily dispersed in the light diffusion layer.

  In particular, when the average particle size of the fine particles is 100 nm or less, optical absorption is small because light absorption in the light diffusion layer is small, which is particularly preferable.

  The average particle diameter of the fine particles can be measured based on JIS Z8901.

  When the optical sheet 11 of the present invention is assembled into an optical module, when the light diffusion layer 17 is a transparent organic medium or a transparent inorganic medium containing fine particles, the luminance distribution on the information display surface of the optical module is made uniform. As a result, for example, when a spot-like or linear light source is used, the shape of the light source of the optical module can be concealed from an observer, which is preferable.

  In the optical sheet 11 of the present invention, the transparent organic medium or transparent inorganic medium of the light diffusion layer 17 is (meth) acrylic resin, polycarbonate resin, polyester resin, polystyrene resin, polyvinyl chloride resin, fluororesin, polyolefin, cellulose acetate. And at least one of silicone resin, polyamide, epoxy resin, polyacrylonitrile resin, polyurethane resin, and glass, while maintaining the optical properties of the light diffusing layer and binding fine particles, Can be maintained, which is preferable.

  In particular, a (meth) acrylic resin, a polycarbonate resin, a polyester resin, a polyvinyl chloride resin, and a fluororesin are preferable because they are excellent in transparency, weather resistance, workability, and dimensional stability. Moreover, when forming the layer which has an optical element surface, since the moldability of an optical element and the softness | flexibility of a sheet | seat are excellent, these resin can be used suitably.

  In the optical sheet 11 of the present invention, the refractive index of the transparent organic medium or the transparent inorganic medium constituting the light diffusion layer 17 is in the range of 1.3 to 2.5, and the optical loss is small, and the optical module This is preferable because the information display becomes clear.

  The refractive index can be measured based on JIS K7105.

  The refractive index of the present invention is a value at a wavelength of 589 nm.

  In the optical sheet 11 of the present invention, the ratio (na / nb) of the refractive index (na) of the transparent organic medium or transparent inorganic medium constituting the light diffusion layer 17 to the refractive index (nb) of the fine particles is 0.52 to 0.52. A range of 0.98 or 1.02 to 1.92 is preferable because light is appropriately diffused in the light diffusion layer, optical loss is small, and information display of the optical module becomes clear. Furthermore, it is more preferable that the ratio (na / nb) is in the range of 0.6 to 0.95 or 1.05 to 1.67 because desired light diffusion occurs in the light diffusion layer. Further, the ratio (na / nb) is more preferably in the range of 0.8 to 0.95 or 1.05 to 1.25.

  The ratio (na / nb) of the refractive index (na) of the transparent organic medium or transparent inorganic medium constituting the light diffusing layer 17 to the refractive index (nb) of the fine particles is more than 0.98 and less than 1.02, that is, When the transparent organic medium or the transparent inorganic medium constituting the light diffusion layer 17 and the refractive index value of the fine particles are substantially the same, desired light diffusion may not occur in the light diffusion layer.

  The thickness of the optical sheet 11 of the present invention is 10 to 2000 μm, preferably 50 to 750 μm, so that the uniformity of the light direction and the luminance distribution can be set to desired optical characteristics, and the optical module is assembled. The optical sheet is preferable because it is easy to handle.

  In the prior art, when a sheet to be used is made thin in order to reduce optical loss, it is difficult to form a sheet, and variations in optical characteristics due to the influence of thickness unevenness are likely to occur. Furthermore, when thin sheets are used in an overlapping manner, since a plurality of optical sheets are used, it is difficult to handle the sheets when assembling the optical module. Therefore, it is difficult to make the optical sheet thin while maintaining optical performance.

  Also, in the prior art, when multiple optical sheets are used, even if the distance between the optical sheets is reduced, there is an air layer between the optical sheets, resulting in optical loss due to reflection on the surfaces of the optical sheets. To do. Further, when a plurality of optical sheets are used, the optical characteristics vary depending on the positions of the optical sheets, so that variations in optical characteristics between the optical modules are likely to occur.

  One of the preferable forms of the optical sheet 11 of the present invention is a configuration having an interface as shown in FIG. For example, in FIG. 2, the light transmission layer 16 a and the light diffusion layer 17 are in contact, and the optical sheet 11 has the interface 14. In other words, the light transmission layer 16a having the optical element surface and the light diffusion layer 17 are integrated.

  When the light transmission layer 16a and the light diffusion layer 17 are a transparent organic medium or a transparent inorganic medium, the compositions of the transparent organic medium or the transparent inorganic medium may be the same or different from each other.

  In one preferred form of the optical sheet 11 of the present invention, for example, in a configuration having an interface as shown in FIG. 2, the manufacturing method of the light transmitting layer 16a and the light diffusing layer 17 is as follows. 2) Integrated molding, that is, a method of forming two or more layers at the same time, and 3) using an ultraviolet curable resin, forming one layer in advance, and applying the ultraviolet curable resin to the other layer, There is a method of irradiating two or more layers. In order to more firmly bind the light transmission layer 16a having the optical element surface at the interface 14 and the light diffusion layer 17, the manufacturing method 2) or 3) is desirable.

  One of the preferable forms of the optical sheet 11 of the present invention is a configuration in which the light transmission layer 16a and the light diffusion layer 17 are integrated in a configuration having an interface as shown in FIG. Therefore, when the optical sheet 11 of the present invention is incorporated in an optical module, the number of sheets assembled in the optical module is reduced as compared with the prior art, so the light absorption in the optical sheet is small, and the optical loss is small. The optical module information can be displayed more clearly.

  One of the preferable forms of the optical sheet 11 of the present invention is a structure in which the light transmission layer 16a and the light diffusion layer 17 are integrated in a structure having an interface as shown in FIG. By using such an optical sheet 11, it is possible to reduce the thickness of the optical module while having optical characteristics equivalent to or higher than those of the conventional technology.

  One of the preferable forms of the optical sheet 11 of the present invention is a structure in which the light transmission layer 16a and the light diffusion layer 17 are integrated in a structure having an interface as shown in FIG. Use of such an optical sheet 11 facilitates assembly into an optical module.

  One of the preferable forms of the optical sheet 11 of the present invention is a configuration in which the light diffusion layer 17 has an optical element surface as shown in FIG. 8, for example. When assembling the optical sheet 11 of the first embodiment of the present invention into an optical module, the number of sheets assembled into the optical module is reduced compared to the prior art, so light absorption in the optical sheet is small and optical loss is reduced. The information of the optical module can be displayed more clearly.

  The optical sheet 11 of the present invention can reduce the number of sheets assembled in the optical module. Therefore, as compared with the case where the light diffusion layer of the prior art and the light transmission layer having the optical element surface are separate, by using the optical sheet of the present invention, the optical loss is reduced, the light transmission amount is increased, and the light source Energy consumption can be reduced.

  In addition, the optical sheet of the present invention is used to reduce the chance of damage to the optical sheet during assembly, as compared to the conventional case where the light diffusion layer and the light transmission layer having the optical element surface are separate. Can do.

  As a light source (not shown) in an optical module using the optical sheet 11 of the present invention, a cold cathode tube, an LED, an organic or inorganic electroluminescence light emitter, and the like can be suitably used.

  The light source in the optical module using the optical sheet 11 of the present invention can be exemplified, for example, at a position opposite to the information display surface of the optical module, that is, at a lower portion of the light diffusion layer in FIG. Not specified. In another form, the light source of the optical module is located on the side of the optical sheet, for example. Further, the light source can be installed on the light transmission layer 16a in FIG. The position of the light source can be set at a desired position depending on the design of the optical module.

  Embodiments of the optical sheet of the present invention will be described in more detail with reference to the drawings.

  FIG. 2 is a partial cross-sectional view of the optical sheet 11 according to the first embodiment of the present invention. The optical sheet 11 includes a light transmission layer 16a and a light diffusion layer 17, and these two layers are laminated in this order. The light transmission layer 16a has the first surface 12 as an optical element surface, and the light diffusion layer 17 has the second surface 13 as a smooth surface. The interface 14 between the light transmission layer 16a and the light diffusion layer 17 is bound to be a smooth surface.

  FIG. 3 is a partial cross-sectional view of the optical sheet according to the second embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a light diffusion layer 17, and a second light transmission layer 16b, and these three layers are laminated in this order. The first light transmission layer 16a has the first surface 12 as an optical element surface, and the second light transmission layer 16b has the second surface 13 as a smooth surface. The interface 14 between the first light transmission layer 16a and the light diffusion layer 17 and the interface 15 between the second light transmission layer 16b and the light diffusion layer 17 are bound to form a smooth surface.

  FIG. 4 is a partial cross-sectional view of the optical sheet according to the third embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a light diffusion layer 17, and a second light transmission layer 16b, and these three layers are laminated in this order. The first light transmission layer 16a has the first surface 12 as the first optical element surface, and the second light transmission layer 16b has the second surface 13 as the second optical element surface. The interface 14 between the first light transmission layer 16a and the light diffusion layer 17 and the interface 15 between the second light transmission layer 16b and the light diffusion layer 17 are bound to form a smooth surface.

  The optical sheet of the present invention can preferably employ an embodiment having two or more optical element surfaces as in the third embodiment in FIG.

  When the optical sheet of the present invention has two or more optical element surfaces, for example, an optical element formed on one optical element surface has a prism shape, and an optical element formed on another optical element surface has a lens shape. The shapes may be different from each other.

  When the optical sheet of the present invention has two or more optical element surfaces having the same shape, the directions and phases of the optical elements formed as unit shapes on the optical element surfaces may be the same or different from each other. Also good. For example, when the optical elements on both optical element surfaces are V-shaped linear prisms, the direction of the ridgeline of the V-shaped linear prism formed on one optical element surface and the V formed on the other optical element surface The directions of the ridge lines of the linear prisms may be the same or different, for example, orthogonal to each other, in order to obtain desired optical characteristics. Further, when the direction of the ridge line of the V-shaped linear prism formed on the two optical element surfaces and the distance between the ridge lines are the same, the position of the ridge line of the V-shaped linear prism formed on one optical element surface and the other The positions of the ridgelines of the V-shaped linear prism formed on the optical element surface are shifted from each other even when they are coincident with each other when viewed from the information display surface of the optical module in order to obtain desired optical characteristics. It may be.

  Thus, compared with an optical sheet having only one optical element surface, an optical sheet having two or more optical element surfaces has a greater degree of freedom in designing the optical sheet due to the combination of the optical element surfaces. This is preferable because the optical characteristics of the module information display can be easily designed.

  FIG. 5 is a partial cross-sectional view of the optical sheet of the fourth embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a third light transmission layer 16c, a light diffusion layer 17, and a second light transmission layer 16b, and these four layers are laminated in this order. The third light transmission layer 16c is sandwiched between the first light transmission layer 16a and the second light transmission layer 16b, and the light diffusion layer 17 is formed between the third light transmission layer 16c and the second light transmission layer 16b. It is sandwiched between the layer 16b. The first light transmission layer 16a has the first surface 12 as the first optical element surface, and the second light transmission layer 16b has the second surface 13 as the second optical element surface. The interface 14 between the third light transmission layer 16c and the light diffusion layer 17, the interface 15 between the second light transmission layer 16b and the light diffusion layer 17, and the first light transmission layer 16a and the third light transmission layer The interface 18 with 16c binds to a smooth surface. The shapes (optical elements) of the first optical element surface and the second optical element surface may be the same shape or different shapes as described above.

  FIG. 6 is a partial cross-sectional view of the optical sheet of the fifth embodiment. The optical sheet 11 is a layer composed of a first surface and a second surface, the first surface 12 is an optical element surface, the second surface 13 is a smooth surface, and the light diffusion layer 17 is an optical layer. It has a configuration with an element surface

  FIG. 7 is a partial cross-sectional view of the optical sheet of the sixth embodiment. The optical sheet 11 is a layer composed of first and second surfaces, the first surface 12 and the second surface 13 are optical element surfaces, and the light diffusion layer 17 has an optical element surface. It is.

  FIG. 8 is a partial cross-sectional view of the optical sheet of the seventh embodiment of the present invention. The optical sheet 11 includes a light diffusion layer 17 and a light transmission layer 16a, and these two layers are laminated in this order. The light diffusion layer 17 has the first surface 12 as the optical element surface, and the light transmission layer 16a has the second surface 13 as the optical element surface. The interface 14 between the light diffusion layer 17 and the light transmission layer 16a is bound to be a smooth surface.

  FIG. 9 is a partial cross-sectional view of the optical sheet of the eighth embodiment of the present invention. The optical sheet 11 includes a light transmission layer 16a and a light diffusion layer 17, and these two layers are laminated in this order. The light transmission layer 16a has the first surface 12 as a smooth surface, and the light diffusion layer 17 has the second surface 13 as a smooth surface. The interface 14 between the light transmission layer 16a and the light diffusion layer 17 is bound to be an optical element surface.

  FIG. 10 is a partial cross-sectional view of an optical sheet according to the ninth embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a light diffusion layer 17, and a second light transmission layer 16b, and these three layers are laminated in this order. The light diffusion layer 17 is sandwiched between the first light transmission layer 16a and the second light transmission layer 16b. The first light transmission layer 16a has the first surface 12 as a smooth surface, and the second light transmission layer 16b has the second surface 13 as a smooth surface. The interface 14 between the first light transmission layer 16a and the light diffusion layer 17 is bound to be the first optical element surface. Further, the interface 15 between the second light transmission layer 16b and the light diffusion layer 17 is bound to be the second optical element surface. The shapes (optical elements) of the first optical element surface and the second optical element surface may be the same shape or different shapes as described above.

  FIG. 11 is a partial cross-sectional view of an optical sheet according to the tenth embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a light diffusion layer 17, and a second light transmission layer 16b, and these three layers are laminated in this order. The light diffusion layer 17 is sandwiched between the first light transmission layer 16a and the second light transmission layer 16b. The first light transmission layer 16a has the first surface 12 as a smooth surface, and the second light transmission layer 16b has the second surface 13 as a smooth surface. The interface 14 between the first light transmission layer 16a and the light diffusion layer 17 is bound to form an optical element surface. Further, the interface 15 between the second light transmission layer 16b and the light diffusion layer 17 is bound to be a smooth surface.

  FIG. 12 is a partial sectional view of an optical sheet according to the eleventh embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a light diffusion layer 17, and a second light transmission layer 16b, and these three layers are laminated in this order. The light diffusion layer 17 is sandwiched between the first light transmission layer 16a and the second light transmission layer 16b. The first light transmission layer 16a has the first surface 12 as a smooth surface, and the second light transmission layer 16b has the second surface 13 as a first optical element surface. The interface 14 between the first light transmission layer 16a and the light diffusion layer 17 is bound to form a second optical element surface. Further, the interface 15 between the second light transmission layer 16b and the light diffusion layer 17 is bound to form a third optical element surface. The shapes (optical elements) of the first optical element surface to the third optical element surface may be the same shape or different shapes as described above.

  FIG. 13 is a partial sectional view of an optical sheet according to the twelfth embodiment of the present invention. The optical sheet 11 includes a first light diffusion layer 17a, a light transmission layer 16, and a second light diffusion layer 17b, and these three layers are laminated in this order. The light transmission layer 16 is sandwiched between the first light diffusion layer 17a and the second light diffusion layer 17b. The first light diffusion layer 17a has the first surface 12 as the first optical element surface, and the second light diffusion layer 17b has the second surface 13 as the second optical element surface. The interface 14 between the first light diffusion layer 17a and the light transmission layer 16 and the interface 15 between the second light diffusion layer 17b and the light transmission layer 16 are bound to form a smooth surface.

  When the first light diffusion layer 17a and the second light diffusion layer 17b in the optical sheet of the twelfth embodiment of the present invention are made of a transparent organic medium or a transparent inorganic medium, the transparent organic medium or the transparent inorganic medium May be the same or different between the first light diffusion layer 17a and the second light diffusion layer 17b. When the kind and amount of fine particles contained in the transparent organic medium or the transparent inorganic medium are different between the first light diffusion layer 17a and the second light diffusion layer 17b, it is preferable because the optical characteristics of the optical sheet 11 can be controlled more easily. .

  The thicknesses of the first light diffusion layer 17a and the second light diffusion layer 17b in the optical sheet of the twelfth embodiment of the present invention may be the same or different from each other. It is preferable that the first light diffusion layer 17a and the second light diffusion layer 17b have different thicknesses because the optical characteristics of the optical sheet 11 can be more easily controlled.

  Thus, in the optical sheet of the twelfth embodiment of the present invention, since the first surface 12 and the second surface 13 are optical element surfaces, the degree of freedom in designing the optical sheet is increased, and the optical module This is preferable because the optical characteristics of the information display can be easily designed. In addition, the shape (optical element) of the first optical element surface and the second optical element surface may be the same as those described above, or may be different from each other. In the same case, the directions and phases of the optical elements formed as unit shapes on the optical element surface may be the same or different from each other, but they are the same from the viewpoint of easy optical property design. Is preferred.

  In the optical sheet according to the twelfth embodiment of the present invention, the refractive index of the first light diffusion layer 17 a and the second light diffusion layer 17 b is preferably larger than the refractive index of the light transmission layer 16. In such a relationship, the light incident on the optical sheet 11 is totally reflected at the interfaces 14 and 15 so that there is no loss of light and the optical characteristics of the optical sheet 11 can be appropriately controlled. For example, by dispersing fine particles having a high refractive index in a transparent organic medium or a transparent inorganic medium constituting the light diffusion layer, the first light diffusion layer 17a and the second light diffusion are compared with the refractive index of the light transmission layer 16. The refractive index of the layer 17b can be increased.

  FIG. 14 is a partial sectional view of an optical sheet according to the thirteenth embodiment of the present invention. The optical sheet 11 includes a first light diffusion layer 17a, a first light transmission layer 16a, a third light transmission layer 16c, a second light transmission layer 16b, and a second light diffusion layer 17b. Two layers are stacked in this order. In the present embodiment, the light transmission layer sandwiched between the first light diffusion layer 17a and the second light diffusion layer 17b is composed of three layers 16a to 16c. It may be a layer or four or more layers. The first light diffusion layer 17a has the first surface 12 as the first optical element surface, and the second light diffusion layer 17b has the second surface 13 as the second optical element surface. The interface 14a between the first light diffusion layer 17a and the first light transmission layer 16a is bound to form a third optical element surface. In addition, the interface 15a between the second light diffusion layer 17b and the second light transmission layer 16b is bound to form a fourth optical element surface. Further, the interface 14b between the first light transmission layer 16a and the third light transmission layer 16c and the interface 15b between the second light transmission layer 16b and the third light transmission layer 16c are bound together to form a smooth surface. It is said. Note that one of the interface 14a and the interface 15a may be a smooth surface. By the way, when only the interface 14a is a smooth surface, the interface 15a becomes a third optical element surface.

  The first light diffusion layer 17a and the second light diffusion layer 17b in the optical sheet of the thirteenth embodiment of the present invention each have two optical element surfaces. For example, in the light diffusion layer 17a, the first surface 12 and the interface 14a that is the surface opposite to the surface 12 are optical element surfaces. The element shapes of these two optical element surfaces may be the same or different from each other. In the case of being the same, the directions and phases of the optical elements may coincide with each other or may differ. Thus, in the optical sheet of the thirteenth embodiment of the present invention, since the first surface 12 and the interface 14a are optical element surfaces, the degree of freedom in designing the optical sheet is increased, and information display of the optical module is performed. It is preferable because the optical characteristics can be easily designed. Further, the interfaces 14a and 15a can be formed as the optical element surface without bringing the interfaces 14a and 15a, which are the optical element surfaces, into contact with the mold. For this reason, it is possible to avoid damaging the optical element surface when the mold is peeled off. Furthermore, since the interfaces 14a and 15a, which are optical element surfaces, are provided inward of the optical sheet, damage to the optical element surface due to impact or the like can be greatly reduced. The matters described above for the first light diffusion layer 17a are the same for the second light diffusion layer 17b.

  In the optical sheet of the thirteenth embodiment of the present invention, the first optical diffusion layer 17a and the second optical diffusion layer 17b each have preferably the same element shape on the two optical element surfaces. For example, in the light diffusing layer 17a, the element shape of each optical element surface of the first surface 12 and the interface 14a is the same, and if the direction and phase match, the light incident on the optical sheet 11 The optical performance can be appropriately controlled. In the same case, it is preferable that the first optical element surface and the second optical element surface are parallel to each other. For example, when the first optical element surface of the first surface 12 and the third optical element surface of the interface 14a between the first light diffusion layer 17a and the first light transmission layer 16a are parallel to each other, The optical element surfaces of the one optical element surface and the third optical element surface have the same shape, direction, and phase, and the thickness of the light transmission layer 16a is substantially uniform. The same can be applied to the two optical element surfaces of the light diffusion layer 17b.

  The refractive index of the first light diffusion layer 17a and the second light diffusion layer 17b of the optical sheet of the thirteenth embodiment of the present invention is larger than that of the first to third light transmission layers 16a to 16c. Is preferred. Moreover, it is preferable that the refractive index of the 1st light transmission layer 16a and the 2nd light transmission layer 16b is larger than the 3rd light transmission layer 16c. With such a configuration, the light incident on the optical sheet 11 is totally reflected at the interfaces 14a, 14b, 15a and 15b, so that there is no loss of light and the optical characteristics of the optical sheet 11 can be appropriately controlled. . When light is incident from the side of the optical sheet, the refractive index of the third light transmission layer 16c is larger than the refractive indexes of the first light transmission layer 16a and the second light transmission layer 16b, and these light transmission layers are transmitted. The refractive indexes of the layers 16a and 16b may be larger than the refractive indexes of the light diffusion layers 17a and 17b. In such a case, since the light incident from the side can be condensed internally, the light can be guided further away.

  In the optical sheet of the thirteenth embodiment of the present invention, the light transmission layer 16a and the light transmission layer 16b may be replaced with a third light diffusion layer (17c) and a fourth light diffusion layer (17d), respectively. . The light diffusing layer 17a and the light diffusing layer (17c) are bound at the interface 14a, but can be distinguished from each other. As a method for distinguishing in this way, for example, the type and amount of fine particles included in the transparent organic medium or the transparent inorganic medium constituting the light diffusion layer or the light diffusion layer can be exemplified. Similarly, the present invention can be applied to the light diffusion layer 17b and the fourth light diffusion layer (17d). The refractive indexes of the light diffusion layers 17a and 17b are preferably larger than those of the light transmission layers (17c) and (17d). The refractive index of the light transmission layers (17c) and (17d) is preferably larger than that of the light transmission layer 16c.

  FIG. 15 is a partial sectional view of an optical sheet according to the fourteenth embodiment of the present invention. The optical sheet 11 includes a first light transmission layer 16a, a first light diffusion layer 17a, a third light transmission layer 16c, a fifth light transmission layer 16e, a fourth light transmission layer 16d, and a second light. The seven layers including the diffusion layer 17b and the second light transmission layer 16b are laminated in this order. In the present embodiment, the light transmission layer sandwiched between the first light diffusion layer 17a and the second light diffusion layer 17b is composed of three layers 16c to 16e. It may be a layer or four or more layers. Further, either the first light diffusion layer 17a or the second light diffusion layer 17b may be omitted. The first light transmission layer 16a has the first surface 12 as the first optical element surface, and the second light transmission layer 16b has the second surface 13 as the second optical element surface. The interface 14a between the first light transmission layer 16a and the first light diffusion layer 17a, the interface 15a between the second light transmission layer 16b and the second light diffusion layer 17b, the first light diffusion layer 17a and the third The interface 14b with the light transmissive layer 16c and the interface 15b between the second light diffusing layer 17b and the fourth light transmissive layer 16d are bonded together, and the third optical element surface and the fourth optical element, respectively. It is considered a surface. Furthermore, the interface 14c between the third light transmission layer 16c and the fifth light transmission layer 16e, and the interface 15c between the fourth light transmission layer 16d and the fifth light transmission layer 16e are bound together to form a smooth surface. It is said. Note that all or part of the interfaces 14a, 14b, 15a, and 15b may be smooth surfaces.

  The shapes of the optical element surfaces (optical elements) included in the first surface 12 and the second surface 13 and the interfaces 14a, 14b, 15a and 15b are the same or different from each other as described above. Also good. In the same case, the direction and the phase of the optical element may coincide with each other or may be different as described above. However, as described above, it is preferable in terms of controlling the optical performance appropriately and easily that the shape of the optical element surface is the same and that the direction and phase of the optical element are the same.

  In the optical sheet of the fourteenth embodiment of the present invention, since the first surface 12 and the interfaces 14a and 14b are optical element surfaces, the degree of freedom in designing the optical sheet is increased, and the information display of the optical module is possible. It is preferable because optical characteristic design can be easily performed. Further, the interfaces 14a and 14b can be formed as the optical element surface without bringing the interfaces 14a and 14b, which are the optical element surfaces, into contact with the mold. For this reason, it is possible to avoid damaging the optical element surface when the mold is peeled off. Furthermore, since the interfaces 14a and 14b, which are optical element surfaces, are provided inside the optical sheet, damage to the optical element surfaces due to impact or the like can be greatly reduced. The second surface 13 and the interfaces 15a and 15b are the same as the first surface 12 and the interfaces 14a and 14b.

  In the optical sheet of the fourteenth embodiment of the present invention, the refractive indexes of the light transmission layers 16a and 16b are preferably different from those of the light diffusion layers 17a and 17b. In addition, the refractive indexes of the light diffusion layers 17a and 17b are preferably different from those of the light transmission layers 16b and 16d. Furthermore, the refractive indexes of the light transmission layers 16b and 16d are preferably different from those of the light transmission layer 16e.

  In the optical sheet according to the fourteenth embodiment of the present invention, the refractive indexes of the light transmission layers 16a and 16e are preferably larger than those of the light diffusion layers 17a and 17b. Further, the refractive index of the light diffusion layers 17a and 17b is preferably larger than that of the light transmission layers 16b and 16d. Furthermore, it is preferable that the refractive index of the light transmission layers 16b and 16d is larger than that of the light transmission layer 16c. With such a configuration, the light incident on the optical sheet 11 is totally reflected at the interface, so that there is no loss of light and the optical characteristics of the optical sheet 11 can be appropriately controlled.

  When light is incident from the side of the optical sheet, the light is collected in the light diffusion layers 17a and 17b through the interfaces 14b and 15b, and the light transmitted through the light diffusion layers 17a and 17b is collected in the interfaces 14a and 15a and the surface 12. , 13 can be emitted as desired optical characteristics. When light is incident from the side of the optical sheet, the refractive index of the light transmission layer 16c is larger than the refractive indexes of the light transmission layers 16b and 16d, and the refractive indexes of the light transmission layers 16b and 16d are light diffusion layers 17a. The refractive index of the light diffusion layers 17a and 17b may be larger than the refractive index of the light transmission layers 16a and 16e. In such a case, since the light incident from the side can be condensed internally, the light can be guided further away.

  In the optical sheet of the fourteenth embodiment of the present invention, since the light transmission layer is in the outer layer, for example, the light incident on the optical sheet is the first surface compared to the case in which the light diffusion layer is in the outer layer. When the light is emitted from the optical sheet, excessive diffusion of the emitted light can be suppressed, and the optical characteristics of the optical sheet can be appropriately controlled.

  By using the optical sheet of the present invention, compared with the prior art, the light absorption of the light emitted from the light source when transmitted through the optical sheet is reduced, and therefore the optical loss can be reduced.

  Further, by using the optical sheet of the present invention, the number of sheets can be reduced, and the energy consumption of the light source can be suppressed. In addition, the optical module can be thinned and the optical module can be easily assembled while having optical characteristics equal to or higher than those of the conventional technology.

  Furthermore, since the optical sheet of the third, fourth, ninth and eleventh embodiments of the present invention has two or more optical element surfaces, it is easy to design optical characteristics optimal for information display of the optical module. Can be done.

  Further, since the optical sheets of the eighth, ninth, tenth and eleventh embodiments of the present invention have the optical element surface in the optical sheet, for example, the influence of the scratch on the surface of the optical sheet when the optical module is assembled. The optimal performance for optical module information display can be maintained.

  By using the optical sheet of the present invention for an optical module, the direction of light emitted from the light source and the uniformity of the luminance distribution, that is, the light diffusibility is set to desired optical characteristics, and the number of optical sheets used in the optical module is reduced. be able to. Therefore, light absorption by the optical sheet is small, and optical loss is small. Further, the optical module can be thinned and the optical module can be easily assembled.

DESCRIPTION OF SYMBOLS 1 ... Optical sheet superposition body 2 ... Transparent resin layer 3 ... Light-diffusion layer 11 ... Optical sheet 12 ... 1st surface 13 ... 2nd surface 14, 15, 18 * ..Interface 16 ... light transmission layer 17 ... light diffusion layer

Claims (18)

In the optical sheet comprising the first and second surfaces and having at least two layers,
At least one surface or interface is an optical element surface;
An optical sheet, wherein at least one layer is a light diffusion layer. The optical sheet according to claim 1, wherein the light diffusion layer has the optical element surface. The optical sheet according to claim 1, wherein at least one of the first and second surfaces has the optical element surface. The optical sheet according to any one of claims 1 to 3, wherein at least one of the first and second surfaces has the optical element surface, and the light diffusion layer has the optical element surface. . The optical sheet according to claim 1, wherein the optical sheet has two or more optical element surfaces. The optical sheet according to claim 5, wherein both the first and second surfaces have the optical element surface. The optical sheet according to claim 5, comprising the light diffusion layer having the first surface as the optical element surface and a light transmission layer. A first light diffusion layer having the first surface as a first optical element surface; and a second light element layer having a second optical element surface that is the same as or different from the first optical element surface. The optical sheet according to claim 5, comprising a light diffusion layer, and a light transmission layer sandwiched between the first light diffusion layer and the second light diffusion layer. At least one of the interface between the first light diffusion layer and the light transmission layer and the interface between the second light diffusion layer and the light transmission layer is the first optical element surface and the second light transmission layer. The optical sheet according to claim 8, wherein the optical sheet has a third optical element surface that is the same as or different from any one of the optical element surfaces. The optical sheet according to claim 9, wherein the first optical element surface, the second optical element surface, and the third optical element surface have the same shape that are parallel to each other. 11. The optical sheet according to claim 7, wherein refractive indexes of the first light diffusion layer and the second light diffusion layer are different from those of the light transmission layer. The optical sheet according to claim 11, wherein the refractive index of the first light diffusion layer and the second light diffusion layer is larger than the refractive index of the light transmission layer. A first light transmission layer having the first surface as a first optical element surface; the light diffusion layer; and a second light transmission layer, wherein the first light transmission layer includes the light diffusion layer. The second optical element surface is the same or different from the first optical element surface, and the second light transmission layer has the interface with the light diffusion layer as the first optical element surface. The optical sheet according to claim 5, wherein the optical sheet has a third optical element surface that is the same as or different from one of the element surface and the second optical element surface. A first light transmission layer having the first surface as a first optical element surface; the light diffusion layer; and a second optical element having the second surface the same as or different from the first optical element surface. A second light-transmitting layer having a surface, and the first light-transmitting layer has the same interface with the light diffusion layer as either the first optical element surface or the second optical element surface. Or the third optical element surface different from both, and the second light transmission layer has an interface with the light diffusing layer as any one of the first optical element surface to the third optical element surface. The optical sheet according to claim 5, wherein the optical sheet has a fourth optical element surface that is the same or different from any other. 15. The first optical element surface, the second optical element surface, the third optical element surface, and the fourth optical element surface have the same shape that are parallel to each other. Optical sheet. The optical sheet according to any one of claims 13 to 15, wherein a refractive index of the first light transmission layer and the second light transmission layer is different from a refractive index of the light diffusion layer. . The optical sheet according to claim 16, wherein the refractive index of the first light transmission layer and the second light transmission layer is larger than the refractive index of the light diffusion layer. The optical sheet according to claim 13 or 14, wherein the second light transmission layer includes a plurality of layers, and a refractive index of the plurality of layers is increased as an outer layer is formed.

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