JP2017097334A - Optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member with which a thin liquid crystal display device having extremely high luminance can be achieved.SOLUTION: An optical member 100 includes a first member 10 having a rugged surface on one side, a second member 20 having a flat counter surface opposing to the rugged surface of the first member 10, and an adhesive layer 30 disposed on the counter surface of the second member. Protrusions of the rugged surface of the first member 10 are bonded to the counter surface of the second member 20 with the adhesive layer 30, and a low refractive index part 40 having a refractive index of 1.30 or less is formed near the adhesion part between the protrusion of the rugged surface and the adhesive layer 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical member. In more detail, this invention relates to the optical member by which the convex part of the said uneven | corrugated surface of the 1st member which has an uneven | corrugated surface is bonded together by the opposing surface of the 2nd member through the contact bonding layer.

  In recent years, there has been a remarkable spread of liquid crystal display devices as image display devices. In a liquid crystal display device, a member having an uneven surface such as a prism sheet, a microlens array, or a lenticular lens may be used. In many cases, such a member having an uneven surface is used separately from other optical members. On the other hand, integration of a member having a concavo-convex surface with another optical member has been studied as the demand for miniaturization and thinning of liquid crystal display devices increases. Specifically, a technique has been proposed in which a convex portion on a concavo-convex surface of a member having a concavo-convex surface is bonded to another optical member. However, according to such a technique, there is a problem that the loss of light at the bonding portion of the convex portion is large and the luminance of the obtained liquid crystal display device is insufficient.

JP 2012-008600 A JP 2012-113951 A Special table 2014-522501 gazette Special table 2010-501897 gazette

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an optical member that can realize a liquid crystal display device that is thin and has extremely high luminance. is there.

The optical member of the present invention includes a first member having a concavo-convex surface on one side, a second member having a flat opposing surface facing the concavo-convex surface of the first member, and an opposing surface of the second member. A convex portion on the concave and convex surface of the first member is bonded to the opposing surface of the second member via the adhesive layer, and a convex portion on the concave and convex surface. A low refractive index portion is formed in the vicinity of an adhesive portion with the adhesive layer, and the refractive index of the low refractive index portion is 1.30 or less.
In one embodiment, the height of the convex portion on the uneven surface of the first member is 1 μm to 100 μm, and a portion of 0.1% to 30% by volume from the tip of the convex portion is in the adhesive layer. In the penetrated state, the convex portion of the uneven surface of the first member is bonded to the opposing surface of the second member.
In one embodiment, the optical member has a low refractive index layer formed on at least a part of the surface of the convex portion of the first member.
In one embodiment, the dynamic elastic modulus at 25 ° C. of the adhesive layer is in the range of 1.0 × 10 ^{6 to} 1.0 × 10 ¹⁰ .
In one embodiment, the first member is selected from a prism sheet, a microlens array, a lenticular lens sheet, and a light guide plate.
In one embodiment, the second member is selected from an absorption polarizer, a polarizer protective film, a reflective polarizer, a retardation film, a substrate with a conductive layer, a wavelength conversion film, and combinations thereof.

  According to the present invention, in the optical member in which the convex portion of the concave / convex surface of the first member having the concave / convex surface on one side is bonded to the flat opposing surface of the second member via the adhesive layer, the first member By forming a low refractive index part in the vicinity of the adhesive part between the convex part of the uneven surface and the adhesive layer, the light can be efficiently retroreflected despite the elimination of the air layer, and therefore the front direction It is possible to secure a sufficient amount of light emitted to the light source and to suppress the generation of light in a direction that cannot be emitted to the viewing side, thereby improving the light utilization efficiency. As a result, it is possible to provide an optical member that can realize a liquid crystal display device that is thin and has extremely high luminance.

It is a schematic sectional drawing explaining the optical member by one Embodiment of this invention. It is a schematic perspective view of an example of a reflective polarizer that can be used as the second member of the optical member of the present invention. It is a graph which compares and shows the polar angle dependence of the diffuse illumination intensity of the liquid crystal display device of Example 1 and Comparative Example 1.

A. Combination of first member and second member in optical member An optical member according to an embodiment of the present invention has a first member having a concavo-convex surface on one side and a flat opposing surface facing the concavo-convex surface of the first member. A second member; and an adhesive layer provided on the opposing surface of the second member. The convex part of the uneven | corrugated surface of a 1st member is bonded together by the opposing surface of a 2nd member through the contact bonding layer. In the optical member according to the embodiment of the present invention, the low refractive index portion is formed in the vicinity of the adhesive portion between the convex portion of the uneven surface of the first member and the adhesive layer. The refractive index of the low refractive index portion is 1.30 or less. Examples of the first member include a prism sheet, a microlens array, a lenticular lens sheet, and a light guide plate. As a 2nd member, as long as it has the flat opposing surface which can adhere | attach with the convex part of a 1st member, arbitrary appropriate optical films and base materials are mentioned according to the objective. Specific examples thereof include an absorption polarizer, a polarizer protective film, a reflective polarizer, a retardation film, a substrate with a conductive layer, a wavelength conversion film, and combinations thereof. The combination of the optical film and the like can be appropriately selected according to the purpose. That is, as the second member, in addition to the above-described optical film or base material alone, any appropriate optical laminate according to the purpose can be mentioned. As a typical example of the configuration of the optical laminate, a polarizing plate (a polarizer protective film / absorptive polarizer / polarizer protective film laminate or a polarizer protective film / absorptive polarizer laminate), retardation Examples include a polarizing plate with a film (a polarizing plate / retardation film laminate: for example, a circular polarizing plate), a polarizing plate / reflection polarizer laminate, and a polarizing plate / reflection polarizer / wavelength conversion film laminate. . It goes without saying that an optical layered body (combination of any appropriate optical film or the like) having any appropriate configuration other than those exemplified above can be used as the second member.

B. Example of Optical Member Hereinafter, a case where the first member is a prism sheet and the second member is any appropriate optical film as a representative example of the optical member according to the embodiment of the present invention will be described with reference to the drawings. . After reading the description of the present embodiment, it is obvious to those skilled in the art that the present invention is similarly applied to any combination of the first member and the second member, and the same effect can be obtained.

B-1. Overall Configuration FIG. 1 is a schematic cross-sectional view illustrating an optical member according to one embodiment of the present invention. The optical member 100 includes a first member (prism sheet) 10, a second member, and an adhesive layer 30. The prism sheet 10 typically includes a base material portion 11 and a prism portion 12. A plurality of prism sheets 10 are arranged on a flat first main surface (flat surface of the base material portion 11) and a second main surface having a concavo-convex shape opposite to the first main surface (on the side opposite to the first main surface). And a concave-convex surface formed by the columnar unit prism 13. The second member 20 has a flat facing surface that faces the uneven surface of the first member. In the embodiment of the present invention, the convex portion by the unit prism 13 on the second main surface of the prism sheet 10 is bonded to the opposing surface of the second member 20 via the adhesive layer 30. In the present specification, such adhesion of only the convex portions of the prism sheet (substantially unit prism) may be referred to as “point adhesion” for convenience.

  As described above, in the optical member according to the embodiment of the present invention, the prism sheet 10 and the second member 20 are integrated by point bonding. Thus, by integrating the prism sheet into the optical member and integrating it, the air layer between the prism sheet and the adjacent layer can be eliminated, which can contribute to the thinning of the liquid crystal display device. . Thinning a liquid crystal display device has a large commercial value because it expands the range of design choices. Furthermore, by integrating the prism sheet, it is possible to avoid damage to the prism sheet due to rubbing when the prism sheet is attached to the surface light source device (backlight unit, substantially light guide plate). The liquid crystal display device which can prevent the display turbidity and has excellent mechanical strength can be obtained.

  In the embodiment of the present invention, the low refractive index portion 40 is formed in the vicinity of the adhesion portion between the convex portion on the uneven surface of the prism sheet and the adhesive layer (that is, in the vicinity of the point adhesion portion). By forming the low refractive index portion in the vicinity of the point adhesion portion, the following advantages can be obtained. In the conventional optical member in which the point adhesion portion is formed and the air layer is excluded, for example, when light from a light source on the back side is incident, the light is not retroreflected and the light escapes to the viewing side. As a result, compared to the case where there is an air layer (when a first member such as a prism sheet is placed separately), the amount of light emitted in the front direction is small, and the light is in a direction that cannot be emitted to the viewing side. In many cases, the problem that the use efficiency of light is reduced due to the occurrence of light. On the other hand, by forming the low refractive index portion in the vicinity of the point adhesion portion, the light is efficiently retroreflected as in the case where the air layer exists. Therefore, it is possible to secure a sufficient amount of light emitted in the front direction and suppress the generation of light in a direction that cannot be emitted to the viewing side, thereby improving the light utilization efficiency. As a result, it is possible to realize a liquid crystal display device having high luminance while realizing a remarkable thinning by eliminating the air layer.

  The low refractive index portion 40 can be formed by, for example, appropriately selecting the shape and material of the unit prism and the viscoelastic characteristics, material, thickness, and the like of the adhesive layer. The low refractive index portion typically has a void inside. The porosity of the low refractive index portion is preferably 30% to 99%, more preferably 50% to 95%, and further preferably 60% to 90%. When the porosity is within the above range, the refractive index of the low refractive index layer can be sufficiently lowered, and high mechanical strength can be realized. As will be described later, the formation of the voids can be promoted by forming a low refractive index layer on the surface of the unit prism.

  The refractive index of the low refractive index portion 40 is 1.30 or less, preferably 1.20 or less, more preferably 1.15 or less. The lower limit of the refractive index of the low refractive index portion is, for example, 1.01. When the refractive index of the low refractive index portion is within such a range, the above-described effect of the low refractive index portion can be further promoted. The refractive index of the low refractive index portion can be adjusted by appropriately selecting the material of the unit prism, the material of the adhesive layer, the porosity, the structure / shape of the void, and the like.

  In one embodiment, the height of the convex part on the uneven surface of the prism sheet (substantially the height of the unit prism 13) is preferably 1 μm to 100 μm, more preferably 2 μm to 50 μm. If the height of the convex portion is within such a range, the low refractive index portion can be formed satisfactorily, and excellent durability and mechanical strength can be realized as an integral optical member.

  In one embodiment, the prism sheet 10 and the second member 20 are preferably 0.1% to 30%, more preferably 0.5% to 25% in volume ratio from the tip of the convex portion of the prism sheet. With the portion penetrating into the adhesive layer 30, point bonding is performed. By performing point bonding in such a state, the low refractive index portion can be formed more satisfactorily, and more excellent durability and mechanical strength can be realized as an integrated optical member.

  In one embodiment, a low refractive index layer (not shown) is formed on at least a part of the surface of the unit prism 13. By forming the low refractive index layer on the surface of the unit prism, the low refractive index portion can be favorably formed in the vicinity of the point adhesion portion. In one embodiment, the low refractive index layer can be selectively formed on a portion of the unit prism that participates in point adhesion. In this case, a liquid crystal display device having high luminance can be realized without affecting other characteristics of the optical member. In another embodiment, the low refractive index layer may be formed on the entire surface of the unit prism. In this case, the first member (as a result, the optical member) can be obtained with excellent manufacturing efficiency.

  Hereinafter, the details of the prism sheet, the low refractive index layer, and the adhesive layer constituting the optical member of the present embodiment will be described.

B-2. Prism Sheet As described above, the prism sheet 10 typically includes the base material portion 11 and the prism portion 12. When the optical member of the present invention is disposed on the backlight side of the liquid crystal display device, the prism sheet 10 allows the polarized light emitted from the backlight unit to remain in the prism portion 12 while maintaining its polarization state. The light is guided to the polarizing plate as polarized light having the maximum intensity in the substantially normal direction of the liquid crystal display device by total reflection or the like. The base material portion 11 may be omitted depending on the purpose and the configuration of the prism sheet. For example, when the layer adjacent to the base material portion side of the prism sheet can function as a support member, the base material portion 11 can be omitted.

B-2-1. Prism Unit The prism sheet 10 (substantially, the prism unit 12) is configured by arranging a plurality of columnar unit prisms 13 that are convex on the side opposite to the first main surface, as described above. Preferably, the unit prism 13 has a columnar shape, and its longitudinal direction (ridge line direction) is configured to be substantially orthogonal to or substantially parallel to the transmission axis of the polarizing plate in the liquid crystal display device.

  Any appropriate configuration can be adopted as the shape of the unit prism 13 as long as the effects of the present invention can be obtained. The unit prisms 13 may have a triangular cross section in a cross section parallel to the arrangement direction and parallel to the thickness direction, and other shapes (for example, one or both of the inclined surfaces of the triangles have different inclination angles. It may be a shape having a plurality of flat surfaces. The triangular shape may be a shape that is asymmetric with respect to a straight line that passes through the vertex of the unit prism and is orthogonal to the sheet surface (for example, an unequal triangular shape), or a shape that is symmetric with respect to the straight line (for example, two An equilateral triangle). Furthermore, the apex of the unit prism may be a chamfered curved surface, or may be cut to have a flat tip at a tip, and may have a trapezoidal cross section. The detailed shape of the unit prism 13 can be appropriately set according to the purpose. For example, as the unit prism 13, the configuration described in JP-A-11-84111 can be employed.

  As for the height of the unit prism 13, all the unit prisms may be the same or may have different heights. When the unit prisms have different heights, in one embodiment, the unit prism has two heights. With such a configuration, only the unit prism having a higher height can be spot-bonded, so that point bonding can be achieved to a desired degree by adjusting the position and number of the unit prisms having a higher height. Can do. For example, unit prisms with high heights and unit prisms with low heights may be alternately arranged, and unit prisms with high (or low) heights may be arranged every third, fourth, fifth, etc. It may be arranged irregularly according to the purpose, or may be arranged at random. In another embodiment, the unit prism has three or more heights. With such a configuration, it is possible to adjust the degree of penetration of the unit prism to be point-bonded into the adhesive, and as a result, it is possible to realize point bonding with a more precise degree.

B-2-2. When providing the base material part 11 in the prism sheet 10, the base material part 11 and the prism part 12 may be integrally formed by extruding a single material. The prism portion may be formed on the film for use. The thickness of the base material portion is preferably 25 μm to 150 μm. With such a thickness, handleability and strength can be excellent.

  Any appropriate material can be adopted as the material constituting the base member 11 depending on the purpose and the configuration of the prism sheet. When the prism portion is formed on the base film, specific examples of the base film include (meth) acrylic resins such as cellulose triacetate (TAC) and polymethyl methacrylate (PMMA). And a film formed of polycarbonate (PC) resin. The film is preferably an unstretched film.

  When the base material portion 11 and the prism portion 12 are integrally formed with a single material, the same material as the material for forming the prism portion when the prism portion is formed on the base material portion film is used as the material. Can do. Examples of the prism portion forming material include epoxy acrylate-based and urethane acrylate-based reactive resins (for example, ionizing radiation curable resins). In the case of forming an integrally structured prism sheet, a polyester resin such as PC or PET, an acrylic resin such as PMMA or MS, or a light-transmitting thermoplastic resin such as cyclic polyolefin can be used.

  The base material part 11 preferably has substantially optical isotropy. In this specification, “substantially optically isotropic” means that the retardation value is small enough not to substantially affect the optical characteristics of the liquid crystal display device. For example, the in-plane retardation Re of the base material portion is preferably 20 nm or less, and more preferably 10 nm or less. The in-plane retardation Re is an in-plane retardation value measured with light having a wavelength of 590 nm at 23 ° C. The in-plane phase difference Re is represented by Re = (nx−ny) × d. Here, nx is the refractive index in the direction in which the refractive index is maximum in the plane of the optical member (that is, the slow axis direction), and ny is the direction perpendicular to the slow axis in the plane (that is, the fast phase). (Axial direction), and d is the thickness (nm) of the optical member.

Furthermore, the photoelastic coefficient of the base portion 11 is preferably ^{-10 × 10 -12 m 2 / N~10} × 10 -12 m 2 / N, more preferably -5 × ¹⁰ -12 ^m 2 / N a ^{~5 × 10 -12 m 2 / N} , more preferably from ^{-3 × 10 -12 m 2 / N~3} × 10 -12 m 2 / N.

B-3. Low Refractive Index Layer The low refractive index layer typically has voids therein. The porosity of the low refractive index layer is, for example, 5% to 90%, preferably 25% to 80%. When the porosity is within the above range, the refractive index of the low refractive index layer can be sufficiently lowered, and high mechanical strength can be realized.

Examples of the low refractive index layer having voids therein include a porous layer and / or a low refractive index layer having at least a part of an air layer. The porous layer typically includes aerogels and / or particles (eg, hollow microparticles and / or porous particles). The low refractive index layer may be preferably a nanoporous layer (specifically, a porous layer having a diameter of 90% or more of fine pores in the range of 10 ⁻¹ to 10 ³ nm).

  Any appropriate material can be adopted as the material constituting the low refractive index layer. As said material, the material as described in international publication 2004/113966 pamphlet, Unexamined-Japanese-Patent No. 2013-254183, and Unexamined-Japanese-Patent No. 2012-189802 can be employ | adopted, for example. Specifically, for example, silica-based compounds; hydrolyzable silanes, and partial hydrolysates and dehydrated condensates thereof; organic polymers; silanol-containing silicon compounds; silicates in contact with acids and ion exchange resins Active silica obtained by the polymerization; polymerizable monomers (for example, (meth) acrylic monomers, and styrene monomers); curable resins (for example, (meth) acrylic resins, fluorine-containing resins, and urethane resins); and These combinations are mentioned.

Any appropriate particles can be adopted as the particles. The particles are typically made of a silica-based compound. Examples of the shape of the particles include a spherical shape, a plate shape, a needle shape, a string shape, and a grape bunch shape. Examples of the string-like particles include particles in which a plurality of particles having a spherical shape, a plate shape, or a needle shape are arranged in a bead shape, or short fiber particles (for example, described in JP-A-2001-188104). Short fiber particles), and combinations thereof. The string-like particles may be linear or branched. Examples of grape tuft-like particles include those obtained by agglomerating a plurality of spherical, plate-like, and needle-like particles into a grape tuft. The shape of the particles can be confirmed, for example, by observing with a transmission electron microscope. The average particle diameter of the particles is, for example, 5 nm to 200 nm, preferably 10 nm to 200 nm. By having the above configuration, a low refractive index layer having a sufficiently low refractive index can be obtained, and the transparency of the low refractive index layer can be maintained. In the present specification, the average particle diameter is given by the formula of average particle diameter = (2720 / specific surface area) from the specific surface area (m ² / g) measured by the nitrogen adsorption method (BET method). It means a value (see JP-A-1-317115).

  The thickness of the low refractive index layer is preferably 0.2 μm to 5 μm, more preferably 0.3 μm to 3 μm. When the thickness of the low refractive index layer is in such a range, a low refractive index portion having a desired refractive index and a desired size can be formed in the vicinity of the point adhesion portion.

  As a method for obtaining a low refractive index layer, for example, JP 2010-189212 A, JP 2008-040171 A, JP 2006-011175 A, International Publication No. 2004/113966 Pamphlet, and references thereof. Can be mentioned. Specifically, silica-based compounds; hydrolyzable silanes, a method of hydrolyzing and polycondensing at least one of a partially hydrolyzed product and a dehydrated condensate thereof, porous particles and / or hollow fine particles are used. Examples thereof include a method and a method of generating an airgel layer using a springback phenomenon. Note that the low refractive index layer may be formed by applying a composition containing the above-described material onto the surface of the convex portion (in the present embodiment, a unit prism) of the first member. In this case, the low refractive index layer can be selectively formed in a desired portion by applying using a predetermined mask.

B-4. Adhesive Layer The adhesive layer 40 has a dynamic elastic modulus at 25 ° C. of preferably 1.0 × 10 ⁴ (Pa) to 1.0 × 10 ¹² (Pa), more preferably 1.0 × 10 ⁶ (Pa Pa) to 1.0 × 10 ¹⁰ (Pa). When the dynamic elastic modulus of the adhesive layer is within such a range, an optical member having excellent durability at the point adhesion portion can be obtained. More specifically, if the dynamic elastic modulus of the adhesive layer is in such a range, the penetration state of the convex portion (the tip portion of the unit prism in this embodiment) into the adhesive layer changes with time. Can be prevented. As a result, it is possible to prevent changes over time in the refractive index, shape, size, etc. of the low refractive index portion, and thus prevent changes over time in the optical characteristics of the low refractive index portion (resulting in the optical member). it can. The dynamic elastic modulus E ^* is represented by the following formula and can be measured according to JIS K 7244.
E ^* = {(E ′) ² + (E ″) ² } ^1/2
(E 'is storage modulus, E "is loss modulus)

  The adhesive layer 40 can be composed of any appropriate adhesive or pressure-sensitive adhesive. Preferably, the adhesive layer 40 may be made of a material that can satisfy the desired dynamic elastic modulus. Typical examples of the material constituting such an adhesive or pressure-sensitive adhesive include acrylic resins, polyvinyl alcohol resins, epoxy resins, unsaturated polyesters, urethane resins, urea resins, melamine resins, and phenol resins. If necessary, a curing agent may be used in combination. An acrylic resin is preferable. This is because it is easily available and desired characteristics can be realized by adjusting the type and blending amount of the copolymer component. More preferably, it is an adhesive containing an acrylic resin. This is because it is easy to achieve a desired dynamic elastic modulus. Examples of the monomer component (copolymerization component) constituting the acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-2- Nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meta ) Acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, 4-methyl- -(Meth) acrylic acid (1-20 carbon atoms) alkyl esters such as propylpentyl (meth) acrylate and n-octadecyl (meth) acrylate; cycloalkyl (meta) such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate ) Acrylate; aralkyl (meth) acrylate such as benzyl (meth) acrylate; 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3 Polycycles such as methyl-2-norbornylmethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate Expression (meta) 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl ( Alkoxy or phenoxy group-containing (meth) acrylates such as (meth) acrylate and alkylphenoxypolyethylene glycol (meth) acrylate; N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meta) ) N-alkyl group-containing (meth) acrylamide derivatives such as acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide; N-methylol ( N-hydroxyalkyl group-containing (meth) acrylamide derivatives such as (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N-propane (meth) acrylamide; N-methoxymethylacrylamide, N-ethoxymethylacrylamide, etc. N-alkoxy group-containing (meth) acrylamide derivatives. In addition to the above, cyclic ether group-containing (meth) acrylamide derivatives can also be used. Specific examples include heterocycle-containing (meth) acrylamide derivatives in which the nitrogen atom of the (meth) acrylamide group forms a heterocycle, such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine etc. are mentioned. These may be used alone or in combination of two or more. By adjusting the type, number, and copolymerization ratio of these monomers, desired characteristics can be realized.

B-5. Modifications of the first member From the B-1 to the B-4, the embodiment in the case where the first member is a prism sheet has been described. However, as described above, also for any first member having an uneven surface. It is obvious to those skilled in the art that the present invention is similarly applied and the same effect can be obtained. For example, when the first member is a microlens array, the vertices of microlenses (convex lenses) arranged in a lattice shape can be point-bonded to the second member. Further, for example, when the first member is a lenticular lens sheet, the apexes of cylindrical lenses (corresponding to unit prisms of the prism sheet) arranged in parallel can be point-bonded to the second member. Further, as described above, the first member may be a light guide plate. As the light guide plate, a light guide plate in which a lens pattern or a prism shape or the like is formed on the viewing side is used so that light from the lateral direction can be deflected in the thickness direction, and preferably on the back side and the viewing side. A light guide plate having a prism shape is used. In the light guide plate, the prism shape formed on the back side and the prism shape formed on the viewing side are preferably perpendicular to each other in the ridge line direction. If such a light guide plate is used, light that is more easily condensed can be made incident on the second member. When the first member is a light guide plate in which a prism shape is formed on the viewing side, the apexes of the prism shapes arranged in parallel can be point-bonded to the second member.

C. Second member As described above, the second member can be any suitable optical film or base material depending on the purpose as long as it has a flat opposing surface that can be point-bonded to the convex portion of the first member. Examples thereof include an absorbing polarizer, a polarizer protective film, a reflective polarizer, a retardation film, a substrate with a conductive layer, a wavelength conversion film, and combinations thereof. Hereinafter, as a representative example, an absorption polarizer, a polarizer protective film, a reflective polarizer, and a wavelength conversion film will be described. However, the present invention also applies to optical films, base materials, and combinations (optical laminates) other than these. It is obvious to those skilled in the art that the same applies and that the same effect can be obtained.

C-1. Absorptive Polarizer Any appropriate polarizer may be adopted as the absorptive polarizer. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

  Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.

  The dyeing with iodine is performed, for example, by immersing a PVA film in an iodine aqueous solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.

  As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.

  The thickness of the polarizer is preferably 25 μm or less, more preferably 3 μm to 22 μm, still more preferably 3 μm to 15 μm, and particularly preferably 3 μm to 12 μm.

C-2. Polarizer Protective Film The polarizer protective film can be composed of any appropriate material. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition. The thickness of the polarizer protective film is preferably 20 μm to 100 μm.

C-3. Reflective Polarizer The reflective polarizer has a function of transmitting polarized light in a specific polarization state (polarization direction) and reflecting light in other polarization states. The reflective polarizer may be a linearly polarized light separation type or a circularly polarized light separation type. Hereinafter, as an example, a linearly polarized light separation type reflective polarizer will be described. Examples of the circularly polarized light separation type reflective polarizer include a laminate of a film in which cholesteric liquid crystal is fixed and a λ / 4 plate.

  FIG. 2 is a schematic perspective view of an example of a reflective polarizer. The reflective polarizer is a multilayer laminate in which layers A having birefringence and layers B having substantially no birefringence are alternately laminated. For example, the total number of layers in such a multilayer stack can be 50-1000. In the illustrated example, the refractive index nx in the x-axis direction of the A layer is larger than the refractive index ny in the y-axis direction, and the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction of the B layer are substantially the same. is there. Accordingly, the difference in refractive index between the A layer and the B layer is large in the x-axis direction and is substantially zero in the y-axis direction. As a result, the x-axis direction becomes the reflection axis, and the y-axis direction becomes the transmission axis. The difference in refractive index between the A layer and the B layer in the x-axis direction is preferably 0.2 to 0.3. The x-axis direction corresponds to the extending direction of the reflective polarizer in the reflective polarizer manufacturing method.

  The A layer is preferably made of a material that exhibits birefringence by stretching. Representative examples of such materials include naphthalene dicarboxylic acid polyesters (for example, polyethylene naphthalate), polycarbonates, and acrylic resins (for example, polymethyl methacrylate). Polyethylene naphthalate is preferred. The B layer is preferably made of a material that does not substantially exhibit birefringence even when stretched. A typical example of such a material is a copolyester of naphthalenedicarboxylic acid and terephthalic acid.

  The reflective polarizer transmits light having a first polarization direction (for example, p-wave) at the interface between the A layer and the B layer, and has a second polarization direction orthogonal to the first polarization direction. Reflects light (eg, s-wave). The reflected light is partially transmitted as light having the first polarization direction and partially reflected as light having the second polarization direction at the interface between the A layer and the B layer. The light utilization efficiency can be increased by repeating such reflection and transmission many times inside the reflective polarizer.

  In one embodiment, as shown in FIG. 3, the reflective polarizer may include a reflective layer R as the outermost layer on the side opposite to the polarizing plate. By providing the reflective layer R, it is possible to further use the light that has not been finally used and has returned to the outermost part of the reflective polarizer, so that the light use efficiency can be further increased. The reflective layer R typically exhibits a reflective function due to the multilayer structure of the polyester resin layer.

  Reflective polarizers can typically be made by combining coextrusion and transverse stretching. Coextrusion can be performed in any suitable manner. For example, a feed block method or a multi-manifold method may be used. For example, the material constituting the A layer and the material constituting the B layer are extruded in a feed block, and then multilayered using a multiplier. Such a multi-layer apparatus is known to those skilled in the art. Next, the obtained long multilayer laminate is typically stretched in a direction (TD) orthogonal to the transport direction. The material constituting the A layer (for example, polyethylene naphthalate) increases the refractive index only in the stretching direction due to the transverse stretching, and as a result, develops birefringence. The refractive index of the material constituting the B layer (for example, a copolyester of naphthalenedicarboxylic acid and terephthalic acid) does not increase in any direction even by the transverse stretching. As a result, a reflective polarizer having a reflection axis in the stretching direction (TD) and a transmission axis in the transport direction (MD) can be obtained (TD corresponds to the x-axis direction in FIG. 2 and MD is the y-axis). Corresponding to the direction). In addition, extending | stretching operation can be performed using arbitrary appropriate apparatuses.

  As the reflective polarizer, for example, the one described in JP-T-9-507308 can be used.

C-4. Wavelength conversion film The above point adhesion can make the effect of a wavelength conversion film remarkable by using the optical layered product containing a wavelength conversion film as the 2nd member. In particular, the hue (problem of yellowishness) of the liquid crystal display device when a wavelength conversion film is used can be remarkably improved.

  The wavelength conversion film typically includes a matrix and a wavelength conversion material dispersed in the matrix.

C-4-1. Matrix Any appropriate material can be used as a material constituting the matrix (hereinafter also referred to as matrix material). Examples of such materials include resins, organic oxides, and inorganic oxides. The matrix material preferably has low oxygen permeability and moisture permeability, high light stability and chemical stability, a predetermined refractive index, excellent transparency, and / or And has excellent dispersibility with respect to the wavelength conversion material. The matrix can practically be composed of a resin film or an adhesive.

C-4-1-1. Resin Film When the matrix is a resin film, any appropriate resin can be used as the resin constituting the resin film. Specifically, the resin may be a thermoplastic resin, a thermosetting resin, or an active energy ray curable resin. Examples of the active energy ray curable resin include an electron beam curable resin, an ultraviolet curable resin, and a visible light curable resin. Specific examples of the resin include epoxy, (meth) acrylate (for example, methyl methacrylate, butyl acrylate), norbornene, polyethylene, poly (vinyl butyral), poly (vinyl acetate), polyurea, polyurethane, aminosilicone (AMS), Polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, silicone fluoride, vinyl and hydride substituted silicones, styrenic polymers (eg, polystyrene, aminopolystyrene (APS), poly ( (Acrylonitrile ethylene styrene) (AES)), polymers cross-linked with bifunctional monomers (eg divinylbenzene), polyester-based polymers (eg polyethylene terf) Rate), cellulosic polymers (e.g., triacetyl cellulose), vinyl chloride polymers, amide-based polymers, imide polymers, vinyl alcohol polymers, epoxy polymers, silicone polymers, acrylic urethane polymer. These may be used alone or in combination (for example, blend, copolymerization). These resins may be subjected to treatments such as stretching, heating, and pressurization after the film is formed. A thermosetting resin or an ultraviolet curable resin is preferable, and a thermosetting resin is more preferable. This is because the present invention can be preferably applied when the optical member of the present invention is manufactured by roll-to-roll.

C-4-1-2. Adhesive When the matrix is an adhesive, any appropriate adhesive can be used as the adhesive. The pressure-sensitive adhesive preferably has transparency and optical isotropy. Specific examples of the pressure-sensitive adhesive include rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and cellulose-based pressure-sensitive adhesives. Preferably, it is a rubber adhesive or an acrylic adhesive.

C-4-2. Wavelength Conversion Material The wavelength conversion material can control the wavelength conversion characteristics of the wavelength conversion film. The wavelength conversion material may be, for example, a quantum dot or a phosphor.

  The content of the wavelength conversion material in the wavelength conversion film (the total content when two or more types are used) is preferably based on 100 parts by weight of the matrix material (typically resin or adhesive solid content). It is 0.01 weight part-50 weight part, More preferably, it is 0.01 weight part-30 weight part. When the content of the wavelength conversion material is in such a range, a liquid crystal display device excellent in hue balance of all RGB can be realized.

C-4-2-1. Quantum dots The emission center wavelength of quantum dots can be adjusted by the material and / or composition, particle size, shape, etc. of the quantum dots.

The quantum dots can be composed of any suitable material. The quantum dots are preferably composed of an inorganic material, more preferably an inorganic conductor material or an inorganic semiconductor material. Examples of semiconductor materials include II-VI, III-V, IV-VI, and IV semiconductors. Specific examples include Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, Sn, Te, SnS PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO is mentioned. These may be used alone or in combination of two or more. The quantum dot may contain a p-type dopant or an n-type dopant. Further, the quantum dot may have a core-shell structure. In the core-shell structure, any appropriate functional layer (single layer or multiple layers) may be formed around the shell according to the purpose, and surface treatment and / or chemical modification may be performed on the shell surface. Good.

  Any appropriate shape can be adopted as the shape of the quantum dot depending on the purpose. Specific examples include a true sphere shape, a flake shape, a plate shape, an elliptic sphere shape, and an indefinite shape.

  As the size of the quantum dot, any appropriate size can be adopted depending on a desired emission wavelength. The size of the quantum dot is preferably 1 nm to 10 nm, more preferably 2 nm to 8 nm. If the size of the quantum dot is in such a range, each of green and red emits sharp light and high color rendering can be realized. For example, green light can be emitted with a quantum dot size of about 7 nm, and red light can be emitted with about 3 nm. In addition, the size of a quantum dot is a dimension along the minimum axis | shaft in the said shape, when it is a shape other than that when a quantum dot is a perfect sphere, for example.

  Details of the quantum dots are described in, for example, JP2012-169271A, JP2015-102857A, JP2015-65158A, JP2013-544018A, and JP2010-533976A. The descriptions of these publications are incorporated herein by reference. A commercial item may be used for the quantum dot.

C-4-2-2. Phosphor As the phosphor, any appropriate phosphor that can emit light of a desired color according to the purpose can be used. Specific examples include a red phosphor and a green phosphor.

An example of the red phosphor is a composite fluoride phosphor activated with Mn ⁴⁺ . The composite fluoride phosphor contains at least one coordination center (for example, M described later), is surrounded by fluoride ions that act as a ligand, and, if necessary, counter ions (for example, A described later) ) Refers to a coordination compound whose charge is compensated. Specific examples thereof include A ₂ [MF ₅ ]: Mn ⁴⁺ , A ₃ [MF ₆ ]: Mn ⁴⁺ , Zn ₂ [MF ₇ ]: Mn ⁴⁺ , A [In ₂ F ₇ ]: Mn ⁴⁺ , A ₂ [ M′F ₆ ]: Mn ⁴⁺ , E [M′F ₆ ]: Mn ⁴⁺ , A ₃ [ZrF ₇ ]: Mn ⁴⁺ , Ba _0.65 Zr _0.35 F _2.70 : Mn ⁴⁺ Here, A is Li, Na, K, Rb, Cs, NH ₄ or a combination thereof. M is Al, Ga, In, or a combination thereof. M ′ is Ge, Si, Sn, Ti, Zr, or a combination thereof. E is Mg, Ca, Sr, Ba, Zn, or a combination thereof. A composite fluoride phosphor having a coordination number of 6 at the coordination center is preferred. Details of such a red phosphor are described in, for example, JP-A-2015-84327. The description of the publication is incorporated herein by reference in its entirety.

Examples of the green phosphor include a compound containing a sialon solid solution having a β-type Si ₃ N ₄ crystal structure as a main component. Preferably, a treatment is performed so that the amount of oxygen contained in such a sialon crystal is a specific amount (for example, 0.8 mass%) or less. By performing such treatment, a green phosphor that emits sharp light with a narrow peak width can be obtained. Details of such a green phosphor are described in, for example, Japanese Patent Application Laid-Open No. 2013-28814. The description of the publication is incorporated herein by reference in its entirety.

  The wavelength conversion film may be a single layer or may have a laminated structure. When the wavelength conversion film has a laminated structure, each layer can typically include a wavelength conversion material having different emission characteristics.

  The thickness of the wavelength conversion film (when having a laminated structure, the total thickness) is preferably 1 μm to 500 μm, more preferably 100 μm to 400 μm. When the thickness of the wavelength conversion film is in such a range, the conversion efficiency and durability can be excellent. When the wavelength conversion film has a laminated structure, the thickness of each layer is preferably 1 μm to 300 μm, more preferably 10 μm to 250 μm.

The water vapor permeability (moisture permeability) in terms of 50 μm thickness of the wavelength conversion film is preferably 100 g / m ² · day or less, and more preferably 80 g / m ² · day or less. The water vapor transmission rate can be measured by a measuring method based on JIS K7129 in an atmosphere of 40 ° C. and 90% RH.

C-4-3. Barrier function Whether the matrix is a resin film or an adhesive, the wavelength conversion film preferably has a barrier function against oxygen and / or water vapor. In the present specification, “having a barrier function” means that the transmission of oxygen and / or water vapor entering the wavelength conversion film is controlled to substantially block the wavelength conversion material from them. The wavelength conversion film can exhibit a barrier function by imparting a three-dimensional structure such as a core-shell type or a tetrapod type to the wavelength conversion material itself. Further, the wavelength conversion film can exhibit a barrier function by appropriately selecting a matrix material.

C-4-4. Others The wavelength conversion film may further contain any appropriate additive depending on the purpose. Examples of the additive include a light diffusing material, a material that imparts anisotropy to light, and a material that polarizes light. Specific examples of the light diffusing material include fine particles composed of an acrylic resin, a silicone resin, a styrene resin, or a copolymer resin thereof. Specific examples of the material that imparts anisotropy to light and / or the material that polarizes light include elliptical spherical fine particles, core-shell fine particles, and laminated fine particles having different birefringence between the major axis and the minor axis. The type, number, blending amount, and the like of the additive can be appropriately set according to the purpose.

  The wavelength conversion film can be formed, for example, by applying a liquid composition containing a matrix material, a wavelength conversion material, and, if necessary, an additive. For example, when the matrix material is a resin, the wavelength conversion film is applied to any appropriate support with a liquid composition containing the matrix material, the wavelength conversion material, and, if necessary, an additive, a solvent, and a polymerization initiator. And then dried and / or cured. The solvent and the polymerization initiator can be appropriately set depending on the type of the matrix material (resin) to be used. Any appropriate application method can be used as the application method. Specific examples include curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar method. It is done. Curing conditions can be appropriately set according to the type of matrix material (resin) used, the composition of the composition, and the like. In addition, when adding a wavelength conversion material to a matrix material, you may add in the state of particle | grains and may add in the state of the dispersion liquid disperse | distributed to the solvent. The wavelength conversion film may be formed on the barrier layer.

  The wavelength conversion film formed on the support can be transferred to other components of the optical member (for example, a retardation film, a substrate with a conductive layer).

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The tests and evaluation methods in the examples are as follows. Unless otherwise specified, “parts” and “%” in the examples are based on weight.

(1) Refractive Index and Film Thickness Measurement Method Refractive index and film thickness were determined by performing reflection measurement using an ellipsometer (product name “Woolum M2000”, manufactured by JA Woollam Co., Ltd.).
(2) Diffuse illuminance A conoscope (manufactured by AUTRONIC MELCHERS Co., Ltd.) is installed above the liquid crystal display devices obtained in the examples and comparative examples at predetermined intervals, and the luminance L is measured every 1 ° in all directions. Thus, the light diffusion illuminance (unit: Lx) was calculated.

<Example 1>
(Coating liquid for low refractive index layer)
0.5 g of 0.01 mol / L oxalic acid aqueous solution was added to a mixed solution in which 0.95 g of methyltrimethoxysilane (MTMS), which is a silicon compound precursor, was dissolved in 2.2 g of dimethyl sulfoxide (DMSO). MTMS was hydrolyzed by stirring at room temperature for 30 minutes to produce tris (hydroxy) methylsilane. Thereafter, after adding 0.38 g of 28% ammonia water and 0.2 g of pure water to 5.5 g of DMSO, the above hydrolyzed mixture was further added, and the mixture was stirred at room temperature for 15 minutes. Gelation of (hydroxy) methylsilane was performed to obtain a gel-like silicon compound. The mixed solution subjected to the gelation treatment was incubated at 40 ° C. for 20 hours as it was to be aged. Next, the aging-treated gel-like silicon compound was crushed into granules of several mm to several cm using a spatula. Thereto, 40 g of isopropyl alcohol (IPA) was added, stirred gently, and then allowed to stand at room temperature for 6 hours to decant the solvent and catalyst in the gel. The same decantation treatment was repeated three times to complete the solvent replacement. Next, the gelled silicon compound in the mixed solution was pulverized. For the pulverization treatment, a homogenizer (trade name “UH-50”, manufactured by SMT Co., Ltd.) was used, and 1.18 g of gel and 1.14 g of IPA were weighed into a 5 cm ³ screw bottle, and then 2 under conditions of 50 W and 20 kHz. Minute grinding was performed. By the pulverization treatment, the gel-like silicon compound in the mixed solution was pulverized. As a result, the mixed solution became a sol solution of a pulverized product. When the volume average particle diameter which shows the particle size variation of the ground material contained in the said liquid mixture was confirmed, it was 0.5 micrometer-0.7 micrometer. Furthermore, a 0.3 wt% KOH aqueous solution was prepared, and 0.02 g of KOH was added to 0.5 g of the sol solution to prepare a coating solution.
(Prism sheet)
A commercially available tablet PC (manufactured by AMAZON, trade name “Kindle Fire HDX 8.9”) is disassembled, the prism sheet included in the backlight side is taken out, and the coating liquid is applied to the prism sheet along the groove of the unit prism. In this way, the coating was performed by a bar coating method and dried at 100 ° C. for 2 minutes to form a low refractive index layer.

(Reflective polarizer)
A 40-inch TV (product name: AQUAS, product number: LC40-Z5) manufactured by SHARP was disassembled, and a reflective polarizer was taken out from the backlight member. The diffusion layer provided on both surfaces of the reflective polarizer was removed to obtain a reflective polarizer of the present embodiment.

(Preparation of polarizing plate)
While immersing a polymer film containing polyvinyl alcohol as a main component [trade name “9P75R (thickness: 75 μm, average polymerization degree: 2,400, saponification degree 99.9 mol%)] manufactured by Kuraray” for 1 minute. After stretching 1.2 times in the transport direction, it is immersed in an aqueous solution with an iodine concentration of 0.3% by weight for 1 minute, so that a film (original length) that has not been stretched in the transport direction is dyed while dyeing. As a result, the film was stretched 3 times. Next, the stretched film was further stretched up to 6 times based on the original length in the transport direction while being immersed in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight, and dried at 70 ° C. for 2 minutes. By doing so, a polarizer was obtained.
On the other hand, an alumina colloid-containing adhesive was applied to one side of a triacetyl cellulose (TAC) film (manufactured by Konica Minolta, product name “KC4UW”, thickness: 40 μm), and this was applied to one side of the polarizer obtained above. They were laminated by roll-to-roll so that the conveying directions of both were parallel. Note that the alumina colloid-containing adhesive is methylol melamine with respect to 100 parts by weight of polyvinyl alcohol resin having an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%). 50 parts by weight is dissolved in pure water to prepare an aqueous solution having a solid content of 3.7% by weight. Alumina colloid (average particle size 15 nm) having a positive charge is added to 100 parts by weight of this aqueous solution with a solid content of 10%. It was prepared by adding 18 parts by weight of an aqueous solution containing by weight. Subsequently, similarly, the TAC film coated with the alumina colloid-containing adhesive was laminated on the opposite surface of the polarizer with a roll-to-roll so that the transport directions thereof were parallel, and then 6 ° C. at 55 ° C. Let dry for minutes. Thus, the polarizing plate which has a structure of TAC film / polarizer / TAC film was obtained.

(Creation of optical member)
The polarizing plate obtained above and a reflective polarizer were bonded together via an acrylic adhesive. In addition, an acrylic photo-curing adhesive is applied to the surface of the reflective polarizer opposite to the polarizing plate, and the convex portions of the prism sheet are adhered to each other, so that the polarizing plate / reflective polarizer / prism sheet is configured. The obtained optical member was obtained. Here, the thickness of the adhesive layer on which the convex portions are point-bonded is 3 μm, the height of the unit prism of the prism sheet is 18 μm, and the tip portion of the unit prism is 3 μm (the volume ratio is 0.5%). ) Penetrated into the adhesive layer, the prism sheet and the polarizing plate / reflection type polarizer laminate were bonded together. The dynamic elastic modulus of the adhesive layer was 1.54 × 10 ⁹ (Pa). In the obtained optical member, a low refractive index portion having a refractive index of 1.12 was formed at a point adhesion portion between the prism sheet and the laminate (substantially a reflective polarizer).

(Production of liquid crystal display device using optical member)
The evaluation was performed using an IPS mode liquid crystal display device (manufactured by AMAZON, trade name “Kindle fire HDX 9.8”). The optical member obtained above was incorporated in the lower side (back side) of the liquid crystal cell to produce a liquid crystal display device. The diffuse illuminance of the obtained liquid crystal display device was measured. The results are shown in Table 1. Further, with respect to the liquid crystal display device, the polar angle dependency of brightness in the direction of 0 ° azimuth (that is, the brightness in the oblique direction) was measured. The results are shown in FIG. 3 together with the results of Comparative Example 1. The luminance is shown as a ratio when the luminance in the front direction (normal direction: polar angle 0 °) is 1.0.

<Comparative Example 1>
An optical member was produced in the same manner as in Example 1 except that the low refractive index layer was not formed on the prism sheet. In the obtained optical member, the low refractive index portion is not formed in the point adhesion portion between the prism sheet and the laminate (substantially, the reflective polarizer), and the refractive index of the portion is 1.47. Met. A liquid crystal display device was produced in the same manner as in Example 1 except that this optical member was used. The obtained liquid crystal display device was subjected to the same evaluation as in Example 1. The results are shown in Table 1. Furthermore, polar angle dependence of diffuse illuminance was measured. The results are shown in FIG. 3 together with the results of Example 1.

<Evaluation>
As apparent from Table 1, according to the example of the present invention, a liquid crystal display device significantly brighter than the comparative example was obtained by forming the low refractive index portion in the vicinity of the point adhesion portion.

  The optical member of the present invention can be suitably used for a liquid crystal display device. Liquid crystal display devices using such optical members are portable devices such as personal digital assistants (PDAs), mobile phones, watches, digital cameras, and portable game machines, OA devices such as personal computer monitors, notebook computers, and copy machines, and video. Household electrical equipment such as cameras, LCD TVs and microwave ovens, back monitors, car navigation system monitors, car audio equipments, display equipments such as commercial store information monitors, security equipment such as surveillance monitors, It can be used for various applications such as nursing care and medical equipment such as nursing monitors and medical monitors.

10 First member (prism sheet)
20 Second member 30 Adhesive layer 40 Low refractive index portion 100 Optical member

Claims (6)

A first member having an uneven surface on one side, a second member having a flat opposing surface facing the uneven surface of the first member, an adhesive layer provided on the opposing surface of the second member, Have
The convex portion of the concave / convex surface of the first member is bonded to the opposing surface of the second member via the adhesive layer, and low refraction occurs in the vicinity of the adhesive portion between the convex portion of the concave / convex surface and the adhesive layer. The rate part is formed,
The refractive index of the low refractive index portion is 1.30 or less,
Optical member.   In the state where the height of the convex portion on the concave-convex surface of the first member is 1 μm to 100 μm and a portion of 0.1% to 30% by volume from the tip of the convex portion penetrates the adhesive layer, The optical member according to claim 1, wherein a convex portion of the uneven surface of one member is bonded to the opposing surface of the second member.   The optical member according to claim 1, wherein a low refractive index layer is formed on at least a part of the surface of the convex portion of the first member. The optical member in any one of Claim 1 to 3 whose dynamic elastic modulus in 25 degreeC of the said contact bonding layer is the range of 1.0 * 10 < ⁴ > (Pa) -1.0 * 10 < ¹² > (Pa).   The optical member according to any one of claims 1 to 4, wherein the first member is selected from a prism sheet, a microlens array, a lenticular lens sheet, and a light guide plate.   6. The device according to claim 1, wherein the second member is selected from an absorption polarizer, a polarizer protective film, a reflective polarizer, a retardation film, a substrate with a conductive layer, a wavelength conversion film, and combinations thereof. An optical member according to any one of the above.