JP2013061429A - Optical sheet and video display device having optical sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sheet capable of enhancing contrast of a video image, and maintaining image clearness while suppressing occurrence of moire and Newton rings.SOLUTION: The optical sheet is arranged between a video light source and a front plate of a video display device, and controls incident light from the video light source to emit it to an observer side. The optical sheet includes: a base material layer; a first optical function layer arranged above the base material layer, and including a plurality of light transmission sections arranged in parallel along the sheet surface, and a plurality of light absorbing sections arranged in parallel between the light transmission sections; and a second optical function layer which includes prisms or lenticular lenses. The first optical function layer is arranged at the video light source side, and the second optical function layer is arranged at the front plate side.

Description

  The present invention relates to an optical sheet, and more particularly, to an optical sheet disposed between a video display panel and a front glass plate, and a video display device including the optical sheet.

  In an image display device that emits an image to an observer, an optical sheet for improving the quality of image light from the image source and emitting the image light to the observer may be provided on the front side of the display device. For example, in a plasma television which is a video display device, when the viewer side is bright, the video contrast may be insufficient and the image quality may deteriorate. Therefore, an optical sheet having an optical functional layer in which black stripes are arranged at regular intervals in the surface direction is arranged on the front surface of a plasma display panel (hereinafter, may be abbreviated as PDP) to appropriately shield outside light. By doing so, the contrast of the video is improved.

  Conventionally, such an optical sheet has been directly attached to the front surface of the display device, but recently, a display device has been developed in which a glass plate is disposed on the forefront surface of the display device to enhance aesthetics. In this case, the optical sheet is sandwiched between the PDP and the glass plate. The display device having such a structure is assembled by stacking and adhering the PDP, the optical sheet, and the front glass plate in this order. Therefore, a Newton ring due to optical interference may occur at the interface between the optical sheet and the front glass plate. Further, even when a space is provided between each of the PDP, the optical film and the front glass plate, the optical film and the front glass plate may partially adhere due to the deflection of the panel, etc. Newton rings may occur in the areas that have been damaged.

  Various countermeasures have been taken against the above problems. For example, Japanese Patent Laying-Open No. 2006-201577 (Patent Document 1) proposes that an interference fringe and a ghost can be prevented from occurring by arranging a diffusion layer having an uneven surface between a PDP and an optical sheet. ing. Japanese Patent Laid-Open No. 2007-298996 (Patent Document 2) proposes that the front glass plate surface facing the optical filter is subjected to anti-glare treatment to make the surface uneven. Furthermore, in Japanese Unexamined Patent Application Publication No. 2008-145602 (Patent Document 3) and Japanese Unexamined Patent Application Publication No. 2011-75768 (Patent Document 4), the light exit surface side of the optical sheet disposed between the PDP and the front glass plate is the mat surface. Has been proposed.

JP 2006-201577 A JP 2007-298996 A JP 2008-145602 A JP 2011-75768 A

  As described above, the problem of moire and Newton's ring can be solved by arranging a light diffusion layer or the like having an uneven surface so that the PDP and the optical functional layer do not adhere to each other. However, when the image light is incident on the uneven surface, the light is diffused there. Of the diffused light, the light in the parallel direction of the black stripe (louver) that is the light absorbing portion of the optical function layer (for example, the vertical direction of the display device) can be absorbed by the optical function layer, but the longitudinal direction of the stripe ( For example, light in the horizontal direction of the display device cannot be absorbed by the optical function layer and is emitted to the viewer side. As a result, the image may be blurred and the image sharpness may deteriorate.

  The present inventors can improve the contrast of an image by arranging a prism or a lenticular lens between the optical functional layer and the front glass plate, and can suppress the occurrence of moire and Newton rings. We obtained the knowledge that an optical sheet that can maintain sharpness can be realized. The present invention is based on this finding.

  Accordingly, an object of the present invention is to provide an optical sheet capable of improving the contrast of an image and maintaining image clarity while suppressing the occurrence of moire and Newton rings.

  Another object of the present invention is to provide a video display device provided with the above optical sheet.

An optical sheet according to the present invention is an optical sheet that is disposed between a video light source and a front plate of a video display device, and controls the incident light from the video light source to be emitted to the viewer side,
A base material layer, a plurality of light transmission parts provided on the base material layer and arranged in parallel along a sheet surface, and a plurality of light absorption parts provided in parallel between the light transmission parts. A first optical functional layer provided; and
A second optical functional layer with a prism or lenticular lens,
The first optical functional layer is disposed on the video light source side, and the second optical functional layer is disposed on the front plate side.

  According to a preferred embodiment of the present invention, the light absorbing portion of the first optical functional layer has a substantially triangular or substantially trapezoidal cross section in the sheet thickness direction, and the substantially triangular bottom or substantially trapezoidal shape. It is arranged so that the lower side of the side faces the viewer.

  Further, according to a preferred embodiment of the present invention, the light absorbing portion of the first optical functional layer has a substantially triangular or substantially trapezoidal cross section in the sheet thickness direction, and the substantially triangular bottom or substantially trapezoidal shape. The lower side has a concave shape.

  A display device according to another embodiment of the present invention is an image display device including an optical sheet, wherein the top of the prism of the optical sheet or the lenticular lens is disposed closer to the viewer than the optical sheet. The optical member or the front plate is disposed via an air interface or at an interval of 5 mm or less.

  In the display device according to a preferred embodiment of the present invention, the optical member disposed closer to the viewer than the optical sheet is an antiglare layer or a light diffusion layer.

  According to the present invention, the optical sheet is provided in parallel between the base material layer, the plurality of light transmission parts provided on the base material layer and arranged in parallel along the sheet surface, and the light transmission part. A plurality of light absorbing portions provided, and a second optical functional layer including a prism or a lenticular lens, so that the image light source side (PDP side) and the front surface When an optical sheet is provided between the glass plate and the first optical functional layer, the contrast is improved and the lens of the second optical functional layer can prevent optical contact with the front glass plate, thus preventing interference. Newton rings do not occur and image clarity can be maintained. Also, the phenomenon such as moire and ghost generated by the first optical functional layer can be eliminated by the prism or lenticular lens of the second optical functional layer.

The schematic sectional drawing of the optical sheet by one Embodiment by this invention in the state integrated in the video display apparatus. The schematic sectional drawing of the optical sheet by another embodiment by this invention in the state integrated in the video display apparatus. The schematic sectional drawing which showed the other example of the light absorption part of a 1st optical function layer. Schematic which showed the one part process of the manufacturing method of the optical sheet shown in FIG. Schematic which showed the other process of the manufacturing method of the optical sheet shown in FIG. FIG. 5 is a schematic cross-sectional view of a display device according to another embodiment of the present invention. FIG. 3 is a schematic view showing a cross-sectional shape of a part of a groove formed on the surface of the light transmission part forming roll used in Example 1;

<Optical sheet>
The optical sheet according to the present invention will be described with reference to the drawings.

  FIG. 1 schematically shows a part of a cross section in the thickness direction in a state in which the optical sheet according to the first embodiment of the present invention is incorporated in an image display device, and FIG. 2 schematically shows a part of a cross section in a thickness direction in a state in which the optical sheet according to the embodiment is incorporated in an image display device.

  The optical sheet 1 is a sheet-like member that is disposed between the video light source 2 and the front plate 3 of the video display device and controls the light incident from the video light source side to be emitted to the viewer side. The optical sheet 1 has a plurality of layers, and includes at least a first optical functional layer 10 and a second optical functional layer 20 as shown in FIGS. The first optical functional layer 10 is disposed on the image light source 2 side, and the second optical functional layer 20 is disposed on the front plate 3 side.

  The first optical functional layer 10 disposed on the image light source 2 side is a layer having a function of appropriately absorbing stray light and external light while controlling the optical path of the image light from the image light source 2 side. The first optical functional layer 10 is provided on the base layer 11, the plurality of light transmission parts 13 provided in parallel along the sheet surface, and in parallel between the light transmission parts 13. A plurality of light absorbing portions 14 provided. Further, as shown in FIG. 1, the second optical functional layer 20 includes a prism 21 a and is disposed closer to the front plate 3 than the first optical functional layer 10. In another embodiment of the present invention, the second optical functional layer 20 includes a lenticular lens 21b as shown in FIG. 2, and is closer to the front plate 3 than the first optical functional layer 10 is. Placed in.

  As described above, the first optical functional layer controls the optical path of the image light from the image light source side and appropriately absorbs stray light and external light. May impair sex. Here, the ghost is the image light transmitted through the light transmission part of the optical filter and the image light totally reflected at the interface between the light transmission part and the light absorption part due to the difference in refractive index between the light transmission part and the light absorption part. Means a double image that appears to overlap. Also. Moire means that when there is no image light (when the display device is turned off), when external light is incident on the optical filter, a shadow of the light absorbing portion is formed on the panel of the display device, and the display panel is caused by the shadow. It means interference fringes generated by interference between the upper and lower shading patterns and the shading pattern (light transmitting portion and light absorbing portion) of the optical filter itself. If the optical sheet is sandwiched between the image light source 2 and the front plate 3 of the image display device, Newton rings may occur due to optical contact.

  In the optical sheet of the present invention, the first optical function is provided by providing the second optical function layer 20 including the prism 21a or the lenticular lens 21b on the surface of the first optical function layer 10 on the front plate 3 side. Ghosts and moire caused by layers can be eliminated. Further, by arranging the optical sheet having such a structure between the image light source 2 and the front plate 3 of the display device, the top of the prism 21a or the lenticular lens 21b is in contact with the front plate 3 through the air interface. Even in this case, since a gap is generated between each prism 21a or each lenticular lens 21b, the optical sheet 1 and the front plate 3 are not in optical contact, and the occurrence of Newton rings can be suppressed. As a result, the contrast of the image can be improved, ghosts and moire can be eliminated, and image clarity can be maintained while suppressing the occurrence of Newton rings. Hereinafter, each constituent layer of the first optical functional layer and the second optical functional layer constituting the optical sheet will be described.

<First optical functional layer>
The base material layer 11 is a layer serving as a base material for forming a light transmission portion 13 described later. The base material layer 11 is preferably composed of a material mainly composed of polyethylene terephthalate (PET). When the base material layer 11 has PET as a main component, the base material layer 11 may contain other resins. Various additives may be added as appropriate. Examples of general additives include phenol-based antioxidants, lactone-based stabilizers, and the like. Here, “main component” means that the PET is contained in an amount of 50% by mass or more with respect to the entire material forming the base material layer (hereinafter the same).

  However, the main component of the material constituting the base material layer 11 is not necessarily PET, and may be other materials. Examples thereof include polybutylene terephthalate, polyethylene naphthalate, terephthalic acid-isophthalic acid-ethylene glycol copolymer, polyester resins such as terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, and polyamide resins such as nylon 6. , Polyolefin resins such as polypropylene and polymethylpentene, acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymer, cellulose resins such as triacetyl cellulose, imide resins and polycarbonate resins Etc. Moreover, you may add additives, such as a ultraviolet absorber, a filler, a plasticizer, an antistatic agent, in these resins suitably as needed. In addition to performance, from the viewpoints of mass productivity, price, availability, etc., it is preferable that the base material layer 11 is composed of a resin mainly composed of PET.

  The light transmission portion 13 is an element having a function of transmitting image light, and the lower side in the substantially trapezoidal section is on the image light source 2 side of the optical sheet 1 and the upper side in the substantially trapezoidal section is along the sheet surface on the front plate 3 side. And each cross section of the light transmission part has a shape extending from the back of the page to the near side. Note that a prism 21a or a lenticular lens 21b of the second optical functional layer 20 to be described later is formed at a portion corresponding to the upper side of the substantially trapezoidal cross section of the light transmitting portion 13.

  As will be described later, the light transmission part 13 can be formed by curing the light transmission part constituting composition. The refractive index of the light transmitting portion 13 is not particularly limited, but is preferably 1.49 to 1.56 from the viewpoint of the availability of the material to be applied.

  For example, a photocurable resin composition in which a photocurable prepolymer, a reactive dilution monomer, and a photopolymerization initiator are blended is preferably used as the light transmitting part constituent composition.

  Examples of the photocurable prepolymer include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.

  Examples of the reactive dilution monomer include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.

  Examples of the photopolymerization initiator include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoylformate compounds, and the like. (Methylbenzoylformate, etc.), thioxanthone compound (isopropylthioxanthone, etc.), benzophenone (benzophenone, etc.), phosphate ester compound (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -Phenylphosphine oxide, etc.) and benzyldimethyl ketal. Of these, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and bis (2,4) are preferable from the viewpoint of preventing coloring of the light transmitting portions 13, 13,. , 6-trimethylbenzoyl) -phenylphosphine oxide. In addition, it is preferable that 0.5-5.0 mass% is contained for the said photoinitiator (S1) on the basis (100 mass%) of light transmission part structure composition whole quantity.

  These photocurable prepolymers, reactive diluent monomers, and photopolymerization initiators can be used alone or in combination of two or more.

  In addition, in the light transmitting part constituting composition, if necessary, silicone additives, rheology control agents, It is also possible to add a defoaming agent, a release agent, an antistatic agent, an ultraviolet absorber and the like.

  Next, the light absorption part which comprises the 1st optical function layer 10 is demonstrated. The light absorbing portion 14 is an element that is disposed between the light transmitting portions 13 described above and has a substantially trapezoidal cross section in the cross section shown in FIGS. 1 and 2. A surface corresponding to the lower side of the substantially trapezoidal cross section is juxtaposed between the upper bases of the substantially trapezoidal cross sections of the light transmitting portion 13. In addition, although not shown, the light absorbing portion 14 may have a substantially triangular cross-sectional shape. Moreover, in preferable embodiment of this invention, as shown to Fig.3 (a), it has the shape 18 in which the surface equivalent to the lower side of the substantially trapezoidal cross section of the light absorption part 14a was dented in the concave shape. Here, the “recessed shape” means that the first optical functional layer 10 is recessed in a concave shape on the base material layer 11 side. The depth of the recess 18 is preferably 1 μm to 6 μm. When the depth of the depression 18 is smaller than 1 μm, the effect of diffusing video light described later may be insufficient. The hypotenuse in the substantially trapezoidal cross section preferably forms an angle of 0 degree or more and 10 degrees or less with respect to the normal direction of the sheet surface of the first optical functional layer 10. In addition, when the angle of the hypotenuse is close to 0 degrees, it is not a trapezoid but a rectangle.

  As shown in FIG. 3 (b), the light absorbing portion may have a cross-sectional shape in which the hypotenuse of the light absorbing portion 14b is a polygonal line, and as shown in FIG. 3 (c), the light absorbing portion 14c. The hypotenuse may be curved.

  In the case shown in FIG. 3A, the light absorbing portion 14a has a substantially trapezoidal cross section. Specifically, the cross-sectional shape of the light absorbing portion 14a is a substantially isosceles trapezoid having an upper side and a lower side and two oblique sides connecting the upper side and the lower side. However, since the surface corresponding to the long lower side of the substantially isosceles trapezoidal section (surface on the front plate 3 side) has a depression, the upper and lower sides of the approximately isosceles trapezoidal section are not exactly parallel. Further, the hypotenuse of the substantially isosceles trapezoidal cross section forms an angle θ1 with respect to the normal line of the sheet exit surface of the optical sheet. θ1 is preferably in the range of 0 to 10 degrees. A more preferable angle is 0 degree to 6 degrees.

  In the case shown in FIG. 3B, the hypotenuse of the light absorption unit 14b (the hypotenuse of the light transmission units 13b and 13b) is not composed of one side but is composed of two sides Hb1 and Hb2. That is, the cross section has a polygonal oblique side. Specifically, in the hypotenuse of the light absorbing portion 14, the hypotenuse Hb1 on the side close to the observer side (the right side of the drawing) forms an angle θ2 with respect to the normal of the optical sheet exit surface. On the other hand, the hypotenuse Hb2 on the side close to the image light source side (the left side in the drawing) forms an angle θ3 with respect to the normal line of the optical sheet incident surface. This angle is in a relation of θ2> θ3, and it is preferable that both of these angles are in the range of 0 ° to 10 °. A more preferable angle is greater than 0 degree and 6 degrees or less. Further, the example of FIG. 3B is an example in which one hypotenuse is constituted by two hypotenuses, but a polygonal line shape may be constituted by more sides.

  In the case shown in FIG. 3C, the inclined surface of the light absorbing portion 14c (the oblique side of the light transmitting portion 13c) is formed in a curved shape. Thus, the hypotenuse which is a substantially trapezoidal cross-sectional shape in a light absorption part may be curvilinear. Even in this case, the angle formed by the curve Hc2 closer to the observer side and the normal line of the light exit surface of the optical sheet than the angle formed by the curve Hc1 closer to the observer side and the normal line of the optical sheet surface. It is preferable that this is smaller. Furthermore, the angle is preferably in the range of more than 0 degree and not more than 10 degrees at any part. A more preferable angle is greater than 0 degree and 6 degrees or less. Here, the angle formed between the curved portion and the normal line of the light exit surface of the optical sheet divides the curve into 10 equal parts, the line connecting the adjacent ends, and the normal line of the optical surface of the optical sheet. Defined by the angle between

  In addition, the shape of the light absorbing portion is not limited to that of the present embodiment, and can be appropriately changed as long as it can absorb external light appropriately. This can include, for example, a case where the cross-sectional shape is substantially rectangular. However, in any case, the surface on the image light source side has a dent recessed in a curved line or a broken line shape.

  The light absorbing portion 14 is made of a predetermined material having a refractive index Nb that is the same as or smaller than the refractive index Np of the light transmitting portion 13. In this way, by setting the refractive index Np of the light transmitting portion 13 and the refractive index Nb of the light absorbing portion 14 to Np ≧ Nb, light is transmitted through the interface between the light absorbing portion 14 and the light transmitting portion 13 under predetermined conditions. The image light from the light source incident on the unit 13 can be appropriately reflected and absorbed. The difference in refractive index between Np and Nb is not particularly limited, but is preferably 0 to 0.06. When the front luminance and the viewing angle are important, a larger value is preferable within this range, and when the black luminance is lowered and the contrast is important, a smaller value is preferable within this range.

  Further, in the present embodiment, the relationship of Np ≧ Nb is preferable as described above. However, the present invention is not necessarily limited to this, and the refractive index of the light transmission part can be made smaller than the refractive index of the light absorption part. It is.

  The light absorbing portion in the present embodiment is configured by filling a light absorbing portion constituting composition containing light absorbing particles and a binder resin between the light transmitting portions 13. That is, the light absorbing particles are dispersed in the binder resin. As a result, out of the image light incident on the first optical functional layer of the optical sheet, the image light incident on the inside of the light absorbing portion 14 without being reflected at the interface between the light transmitting portion and the light absorbing portion is converted into the light absorbing particles. Can be absorbed. Furthermore, it is possible to appropriately absorb external light from the observer side that is incident at a predetermined angle, and it is possible to improve contrast. At this time, the binder resin is made of the material having the refractive index Nb. Although the material used as binder resin is not specifically limited, For example, the photocurable resin composition which mix | blended the following photocurable prepolymer, the reactive dilution monomer, and the photoinitiator is used preferably.

  Examples of the photocurable prepolymer include urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate.

  Examples of the reactive dilution monomer include, as monofunctional monomers, vinyl monomers such as N-vinylpyrrolidone, N-vinylcaprolactone, vinylimidazole, vinylpyridine, and styrene, lauryl (meth) acrylate, and stearyl (meth) acrylate. , Butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) acrylate, Nonylphenoxypolyethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate (Meth) acrylic acid ester monomers such as cyclohexyl (meth) acrylate, benzyl methacrylate, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylate, acryloylmorpholine, And (meth) acrylamide derivatives. Polyfunctional monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polytetra Methylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate Bisphenol A polypropoxydiol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, glyceryl tri (meth) acrylate, propoxylated glyceryl tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate And dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

  Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one. 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. In the present invention, the amount of the photopolymerization initiator contained in the photocurable resin composition is based on the total amount of the photocurable resin composition (100% by mass) from the viewpoint of curability and cost of the photocurable resin composition. It is preferable that it is 0.5-10.0 mass%.

  These photocurable prepolymers, reactive diluent monomers, and photopolymerization initiators can be used alone or in combination of two or more.

  Specifically, a photopolymerizable component composed of urethane acrylate, epoxy acrylate, tripropylene glycol diacrylate and methoxytriethylene glycol acrylate (specifically, photocurable prepolymer and reactive dilution monomer), refractive index, viscosity, Alternatively, in consideration of the influence on the performance of the optical functional layer 12, etc., it can be arbitrarily mixed and used.

  In addition, you may add a silicone, an antifoamer, a leveling agent, a solvent, etc. to a photocurable resin composition as an additive.

  The light-absorbing particles are contained in the light-absorbing part constituting composition, and act to absorb stray light and external light when the light-absorbing part is configured.

  As the light absorbing particles, light absorbing colored particles such as carbon black are preferably used. However, the light absorbing particles are not limited to these, and colored particles that selectively absorb a specific wavelength in accordance with the characteristics of the image light may be used as the light absorbing particles. Specific examples include organic fine particles colored with metal salts such as carbon black, graphite, and black iron oxide, dyes, pigments, colored glass beads, and the like. In particular, colored organic fine particles are preferably used from the viewpoints of cost, quality, availability, and the like. More specifically, acrylic cross-linked fine particles containing carbon black, urethane cross-linked fine particles containing carbon black, and the like are preferably used. Such colored particles are usually contained in the above-mentioned photocurable resin composition in the range of 3 to 30% by mass. The average particle diameter of the colored particles is preferably 1 to 20 μm. Here, the “average particle diameter” means that obtained by particle size measurement by a mass distribution method. By using colored particles having an average particle size of 1 μm or more, when forming the light absorbing portion as described below, the colored particles are not scraped off by the doctor blade, and the upper portion of the light transmitting portion is Can be prevented from remaining on the surface.

  The means for absorbing light is not limited to the method using light absorbing particles as in this embodiment. Other examples include, for example, coloring the entire composition of the light absorbing portion constituting the light absorbing portion with a pigment or dye to form a light absorbing portion colored entirely.

  Next, a method for manufacturing the first optical functional layer 10 will be described. FIG. 4 is a cross-sectional view schematically illustrating a part of the process for an example of the method for manufacturing the first optical functional layer 10. FIG. 5 is a perspective view schematically illustrating another process in the example of the method for manufacturing the first optical functional layer 10.

  When the first optical functional layer 10 of the optical sheet 1 is manufactured, as shown in FIG. 4, the light transmission part 13 is formed on the base material layer 11 (base material 11 ′ including the base material layer), A sheet 10 ′ is obtained. In order to form the light transmission part 13, first, a mold roll 42 having a groove having a shape corresponding to the shape of the light transmission part 13 at a predetermined pitch is prepared. Next, the base material 11 ′ is fed between the mold roll 42 and the nip roll 41. The arrow shown in FIG. 4 is the direction in which the substrate 11 'is fed. In accordance with the feeding of the base material 11 ′, the droplets of the light transmitting portion constituting composition 30 are continuously supplied from the supply device 40 between the mold roll 42 and the base material 11 ′. When the light transmitting portion constituting composition 30 is supplied onto the base material 11 ′ from the supply device 40, a bank 31 in which the light transmitting portion constituting composition 30 is accumulated is formed between the mold roll 42 and the base material 11 ′. To be. In the bank 31, the light transmitting portion constituting composition 30 spreads in the width direction of the base material 11 '.

  The light transmitting part constituting composition supplied between the mold roll 42 and the base material 11 ′ as described above is formed by the pressing force between the mold roll 42 and the nip roll 41. 42 is filled. Thereafter, the light transmissive part 13 can be formed by irradiating the light transmissive part constituting composition with light by the light irradiation device 44 and curing the light transmissive part constituting composition. After the light transmission part 13 is formed, the sheet 10 ′ on which the light transmission part 13 is formed on the sheet 11 ′ is pulled away from the mold roll 42 by being pulled through the peeling roll 43.

  Next, as shown in FIG. 5, the light absorbing portion 14 is formed between the light transmitting portions 13 of the sheet 10 ′ to obtain the first optical functional layer 10. Specifically, the light absorbing portion constituting composition 36 is supplied onto the light transmitting portion 13, and the light absorbing portion constituting composition 36 is filled in the grooves 37 between the light transmitting portions 13 by the doctor blade 35, while surplus portions are filled. The light absorbing portion 14 is formed by scraping off the light absorbing portion constituting composition 36 and irradiating and curing the light absorbing portion constituting composition 36 remaining in the groove 37 between the light transmitting portions 13. it can. The arrow shown in FIG. 5 is the feeding direction of the sheet 10 '.

  At this time, it is preferable that the elastic modulus of the light transmission part 13 is 10 MPa or more and less than 2000 MPa. When the elastic modulus of the light transmitting portion 13 is 2000 MPa or more, it becomes hard and defects such as cracks and chipping occur, or when the light absorbing portion 14 is formed as described above, the surface of the first optical functional layer 10 is formed. There exists a possibility that the external appearance defect may be caused or the transmittance of the first optical functional layer 10 may be reduced. That is, when the light transmission part 13 is too hard, when the surplus portion of the light absorbing part constituting composition 36 supplied onto the light transmission part 13 is scraped by the doctor blade 35, the doctor blade 35 is pressed against the light transmission part 13. However, since the light transmission part 13 does not deform | transform, there exists a possibility that the excess light absorption part structural composition 36 may not be scraped off. If the elastic modulus of the light transmission part 13 is in the above range, when the doctor blade 35 is pressed, due to the deformation of the light transmission part 13, the scraping failure of the surplus light absorption part constituting composition 36 is eliminated, and the first It is possible to prevent appearance defects from occurring on the surface of the optical functional layer 10 and a decrease in the transmittance of the first optical functional layer 10. In addition, since the light transmission part 13 is too soft when the elasticity modulus of the light transmission part 13 is 10 Mpa or less, the light transmission part 13 becomes difficult to release from the mold roll 42 in the process shown in FIG.

<Second optical functional layer>
The second optical functional layer 20 disposed on the front plate 3 side (observer side) of the optical sheet 1 controls the image light emitted from the first optical functional layer 10 and also the first optical functional layer. This is a layer having a function of removing moire and ghost caused by the arrangement. As shown in FIG. 1 or FIG. 2, the second optical functional layer 20 includes a prism 21a or a lenticular lens 21b. Therefore, even if the optical sheet 1 is bonded so that the front plate 3 disposed on the image light side with respect to the optical sheet 1 and other optical members provided as desired and the optical sheet 1 face each other, the second optical function The tops of the prisms 21a or lenticular lenses 21b of the layer 20 are in contact with the front plate 3 and other optical members provided as desired via an air interface, so that each prism 21a or lenticular lens of the second optical functional layer A space is formed between 21b. Therefore, optical adhesion between the front plate 3 or other optical member provided as desired and the optical sheet 1 can be prevented. As a result, by incorporating the optical sheet having the structure described above into the display device, it is possible to eliminate ghosts and moire and maintain image clarity while suppressing the occurrence of Newton rings.

  The prism constituting the second optical functional layer has a structure in which a plurality of conventionally known pre-prisms that are convex on the viewer side are arranged in parallel along the sheet surface and extend from the back of the sheet to the near side. . In addition, the lenticular lens has a structure in which a plurality of conventionally known cylindrical lenses convex on the observer side are arranged in parallel along the sheet surface and extend from the back of the sheet to the near side. It is preferable that the prism and the lenticular lens have a lens pitch such that 1 to 10 prisms or lens units are included between the adjacent light absorbing portions of the first optical functional layer, and more preferably. 2 to 10 pieces. In order to eliminate the occurrence of moiré and ghost as described above, it is preferable that the lens pitch is large. However, a first optical functional layer in which the pitch of the prisms or lenses exceeds 10 is provided between the adjacent light absorbing portions. It becomes difficult to produce.

  The prism or lenticular lens can be produced by a conventionally known method. For example, a photocurable resin composition used when forming a light transmission part having a refractive index of about 1.45 to 1.60 as described above. A metal roll having a groove having a shape corresponding to the lens shape is prepared using the same as described above, and a lens unit having a desired formation can be formed by a method similar to the method shown in FIG. it can.

<Display device>
In the display device according to the present invention, as shown in FIG. 1, the optical sheet 1 described above is disposed between the image light source 2 and the front plate 3 of the display device, and the prism of the second optical functional layer 20. The top of 21a is arrange | positioned so that the front plate 3 may contact | connect via an air interface. The optical sheet 1 may not be in contact with the front plate 3 through the air interface, but may be arranged with an interval of 5 mm or less. From the viewpoint of preventing the occurrence of Newton rings, the optical sheet 1 and the front plate 3 may be arranged with a gap so as not to contact each other as described above, but the top of the prism 21a of the optical sheet 1 and the front plate 3 If the distance to the distance exceeds 5 mm, the image will be blurred. Therefore, the distance between the gaps is preferably short. In the display device according to the present invention, since the optical sheet 1 includes the first optical functional layer and the second optical functional layer, the top of the prism 21a of the optical sheet 1 is placed on the front plate 3 via the air interface. Even when they are in contact with each other, the occurrence of Newton rings can be prevented. Although not shown, it goes without saying that an optical sheet in which the second optical functional layer 20 as shown in FIG. 2 is provided with a lenticular lens 21b can also be applied to a display device.

  FIG. 6 is a schematic cross-sectional view of a display device according to another embodiment of the present invention. In the display device, another optical member 4 such as a light diffusion layer may be disposed between the optical sheet 1 and the front plate 3. Further, an antireflection filter 5, an antiglare layer, or the like may be disposed closer to the observer than the front plate 3. Further, an electromagnetic wave shielding layer 8 and a wavelength filter layer 9 may be disposed between the optical sheet 1 and the image light source 2 via an adhesive layer 7. Further, although not shown, a hard coat layer or the like may be disposed on the front surface of the front plate 3 or the antireflection filter 5. Hereinafter, each member which comprises the display apparatus by this invention is demonstrated. Hereinafter, each member which comprises the display apparatus by this invention is demonstrated.

  Examples of the image light source 2 of the display device according to the present invention include, but are not limited to, a general plasma display panel (PDP), but a liquid crystal display (LCD), an electroluminescent display (EL), a cathode ray tube display. (CRT) may be used.

  The front plate 3 disposed closer to the viewer than the optical sheet 1 of the display device has a function of protecting the surface of the optical sheet as described above and a function of giving design appearance to the appearance of the display device. As the front plate, a glass plate is usually used, but the front plate is not limited to this and may be a transparent resin plate. As a transparent resin board, if it has said function, it can use without a restriction | limiting especially, For example, polyester resin boards, such as a polyethylene terephthalate, an acrylic resin board, a polycarbonate resin board, etc. are mentioned.

  The optical member 4 that may be disposed between the optical sheet 1 and the front plate 3 according to the present invention will be described. Examples of the optical member disposed between the optical sheet 1 and the front plate 3 include a light diffusion layer. The light diffusion layer is a layer having a function of diffusing outgoing light. A commercially available layer can be used as such a light diffusion layer.

  Next, the antireflection layer 5 will be described. The antireflection layer 5 is a layer that is disposed on the most observer side of the display device and has a function of preventing reflection of external light. According to this, it is possible to prevent external light from being reflected on the surface of the front plate on the viewer side and returning to the viewer side, so-called reflection is generated, making it difficult to see the image. Such an antireflection layer can be constituted by using a commercially available antireflection film.

  Next, the pressure-sensitive adhesive layer 7 provided when the optical sheet 1 according to the present invention and the electromagnetic wave shielding layer 8 are bonded together will be described. The pressure-sensitive adhesive layer 7 is a layer composed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive. As the pressure-sensitive adhesive, known ones that can obtain necessary light transmittance, pressure-sensitive adhesiveness, and weather resistance can be used. The pressure-sensitive adhesive composition may contain a UV absorber, a near-infrared absorber, a neon ray absorber, a toning pigment, and the like.

  The pressure-sensitive adhesive means a material that can be bonded only with the tackiness of the surface only by moderate pressurization (usually, light pressing by hand). In order to develop the adhesive strength of the pressure-sensitive adhesive, usually, physical energy or action such as heating, humidification, radiation (ultraviolet ray, electron beam, etc.) irradiation is unnecessary, and chemical reaction such as polymerization reaction is also unnecessary. In addition, the pressure-sensitive adhesive can maintain the adhesive strength to the extent that it can be re-peeled after bonding.

The thickness of the pressure-sensitive adhesive layer 7 is preferably 20 μm to 50 μm or less. The thickness of the pressure-sensitive adhesive layer 7 refers to the thickness of the thickest part of the pressure-sensitive adhesive layer 7. If the thickness of the pressure-sensitive adhesive layer 7 is less than 20 μm, the ability to follow irregularities is lowered and a problem of biting bubbles occurs, and if it exceeds 50 μm, it is difficult to uniformly apply the pressure-sensitive adhesive composition. Furthermore, the elastic modulus of the pressure-sensitive adhesive layer 7 is desirably 1 × 10 ⁴ or more and 1 × 10 ⁵ Pa or less. When larger than this, the followability to unevenness will fall and the malfunction which bites a bubble will generate | occur | produce, and when smaller than this, it will be soft and the malfunction of the stain | pollution | contamination by the protrusion of an adhesive composition will generate | occur | produce.

  The pressure-sensitive adhesive layer 7 uses an adhesive having an acid value as the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 7 from the viewpoint of increasing the adhesion between the electromagnetic wave shielding layer 8 and the optical sheet 1 described below. preferable. As an adhesive which has an acid value, what has an acid value is mentioned, for example among natural rubber and a synthetic resin. Examples of the adhesive having an acid value include those composed of a substance having a carboxyl group in the molecule. Specifically, an acrylic adhesive is preferable from the viewpoint of high transparency. Moreover, it is preferable that the acid value of an acrylic adhesive is 1 or more from the point which can make the adhesiveness of the electromagnetic wave shielding layer 8 and the optical sheet 1 favorable.

  As the acrylic pressure-sensitive adhesive having an acid value contained in the pressure-sensitive adhesive layer 7, the optical sheet of the present invention has appropriate adhesive strength, transparency, and coating suitability from those commonly used as known pressure-sensitive adhesives. A transmission spectrum that does not substantially change the transmission spectrum is appropriately selected.

  The acrylic pressure-sensitive adhesive having an acid value is a polymer containing at least a (meth) acrylic acid alkyl ester monomer and is a (meth) acrylic acid alkyl ester monomer having an alkyl group of about 1 to 18 carbon atoms. Generally, it is a copolymer of a monomer having a carboxyl group. The adhesive ability of the pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer 7 is manifested by strongly adsorbing carboxyl groups present in the pressure-sensitive adhesive molecules on the surface of the copper mesh layer of the electromagnetic wave shielding layer 8. In the present invention, (meth) acrylic acid refers to acrylic acid and / or methacrylic acid.

  Examples of (meth) acrylic acid alkyl ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, sec-propyl (meth) acrylate, (meth) acrylic acid. n-butyl, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid Examples thereof include n-octyl, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, undecyl (meth) acrylate, and lauryl (meth) acrylate. Of these, butyl acrylate and 2-ethylhexyl acrylate are preferable, and butyl acrylate and 2-ethylhexyl acrylate are preferably used in combination. Moreover, the said (meth) acrylic-acid alkylester is normally copolymerized in the quantity of 30.0 mass parts-99.5 mass parts in acrylic adhesive.

  Moreover, as a monomer which has a carboxyl group which forms an acrylic adhesive, monomers containing a carboxyl group such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, monobutyl maleate and β-carboxyethyl acrylate are used. Can be mentioned.

  Furthermore, in addition to the above, the acrylic pressure-sensitive adhesive used in the present invention may be copolymerized with a monomer having another functional group within a range that does not impair the characteristics of the acrylic pressure-sensitive adhesive. Examples of monomers having other functional groups include monomers containing hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and allyl alcohol; (meth) acrylamide, N-methyl Monomers containing amide groups such as (meth) acrylamide and N-ethyl (meth) acrylamide; Monomers containing amide groups and methylol groups such as N-methylol (meth) acrylamide and dimethylol (meth) acrylamide; Monomers containing amino groups such as (meth) acrylate and dimethylaminoethyl (meth) acrylate; and epoxy group-containing monomers such as allyl glycidyl ether and (meth) acrylic acid glycidyl ether. Other examples include fluorine-substituted (meth) acrylic acid alkyl esters and (meth) acrylonitrile, vinyl group-containing aromatic compounds such as styrene, methylstyrene, and vinylpyridine, vinyl acetate, and vinyl halide compounds. it can.

  Furthermore, in the acrylic pressure-sensitive adhesive used in the present invention, in addition to the monomer having other functional groups as described above, another monomer having an ethylenic double bond can be used. Examples of monomers having an ethylenic double bond include diesters of α, β-unsaturated dibasic acids such as dibutyl maleate, dioctyl maleate and dibutyl fumarate; vinyl esters such as vinyl propionate; vinyl ethers; And vinyl aromatic compounds such as vinyl toluene.

  In addition to the monomer having an ethylenic double bond as described above, a compound having two or more ethylenic double bonds may be used in combination. Examples of such compounds include divinylbenzene, diallyl malate, diallyl phthalate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, methylene bis (meth) acrylamide, and the like.

  Furthermore, in addition to the above-described monomers, monomers having an alkoxyalkyl chain can be used. Examples of (meth) acrylic acid alkoxyalkyl esters include 2-methoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, and 3-methoxypropyl (meth) acrylate. , 2-methoxybutyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate And so on. As commercial products of these acrylic pressure-sensitive adhesives, for example, “5407” manufactured by Nippon Synthetic Chemical Co., Ltd. is preferably used.

  By including an antioxidant, the pressure-sensitive adhesive layer 7 can prevent discoloration of the electromagnetic wave shielding layer 8 while using a pressure-sensitive adhesive having good acidity. The compound used as the antioxidant is selected from benzotriazole antioxidants, phenolic antioxidants, phosphite antioxidants, amine antioxidants, sulfur-containing organometallic salt antioxidants, etc. Although it can be used, it is preferable that the antioxidant contained in the adhesive layer 20 is a benzotriazole antioxidant from the viewpoint of the blue discoloration prevention performance of the copper mesh layer of the electromagnetic wave shielding layer 8.

  Examples of the benzotriazole antioxidants include compounds characterized by containing at least the structure of the following formula (1) as a skeleton, and sodium salts, potassium salts, and amine salts thereof. Examples of the substituent that may be included in the structure of the following formula (1) include an alkyl group that may have a substituent, an aryl group that may have a substituent, and a halogen atom. It is done.

  Specifically, 1,2,3-benzotriazole (1H-benzotriazole), 1H-benzotriazole sodium salt, 4-methyl-1H-benzotriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H -Benzotriazole potassium salt, 5-methyl-1H-benzotriazole potassium salt, 4-methyl-1H-benzotriazoleamine salt, 5-methyl-1H-benzotriazoleamine salt, 2- (3,5-di-t- Butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole and the like, among which 1,2,3-benzotriazole (1H -Benzotriazole) is preferred.

  In the pressure-sensitive adhesive layer 7, containing 1 part by mass or more of the benzotriazole-based antioxidant with respect to 100 parts by mass of the pressure-sensitive adhesive has sufficient adhesive force of the pressure-sensitive adhesive layer 7 and copper in the electromagnetic wave shielding layer 8. This is preferable because the surface of the mesh layer is not discolored. When content of antioxidant is less than the said range, even if antioxidant is contained in the adhesive layer 7, there exists a possibility that discoloration of the copper mesh layer of the electromagnetic wave shielding layer 8 cannot fully be prevented.

  In particular, the acid value of the pressure-sensitive adhesive is preferably 1 or more, and the pressure-sensitive adhesive layer 7 preferably contains 1 part by mass or more of the benzotriazole-based antioxidant with respect to 100 parts by mass of the pressure-sensitive adhesive.

  Furthermore, in the pressure-sensitive adhesive layer according to the present invention, a curing agent (crosslinking agent) such as an isocyanate compound, a tackifier, a silane coupling agent, a filler, and the like can be blended as desired.

  Next, the electromagnetic wave shielding layer 8 will be described. The electromagnetic wave shielding layer 8 is a layer having a function of shielding electromagnetic waves generated from the display device side. As long as the layer has the function, a means for blocking electromagnetic waves is not particularly limited. For example, the copper mesh layer can be formed on a transparent substrate by an etching method, a printing method, a vapor deposition method, or a sputtering method, and is appropriately designed depending on the electromagnetic wave to be blocked. As a method for forming a copper mesh layer, a method of patterning a metal foil by a photolithography method after laminating a transparent base material and a metal foil with an adhesive (for example, JP-A-11-145678) is selected. In addition, discoloration of the electromagnetic wave shielding layer 8 can be prevented by adding the antioxidant to the adhesive.

  Next, the wavelength filter layer 9 will be described. The wavelength filter layer 9 is a layer having a function of suppressing transmission of light having a predetermined wavelength. The wavelength whose transmission should be suppressed can be appropriately selected as necessary. Specific examples of the wavelength filter layer 9 include a layer for cutting neon lines emitted from the PDP, a layer for cutting infrared rays, near infrared rays and ultraviolet rays, a layer for adjusting color tone, and the like. Below, a layer that cuts near infrared rays (near infrared absorption filter), a layer that cuts neon lines (neon light absorption filter), a layer that adjusts color tone (color tone adjustment filter), and a layer that cuts ultraviolet rays (ultraviolet absorption filter) ).

  As the near-infrared absorbing filter, a commercially available film having a near-infrared absorbing agent (for example, trade name No. 2832 manufactured by Toyobo Co., Ltd.) or a composition containing a near-infrared absorbing dye in the adhesive layer or the resin layer is used. A film formed or coated on a transparent substrate or other functional filter, and formed through drying, curing treatment or the like as required can be used.

  As the near-infrared absorbing dye, a near-infrared region generated due to the xenon gas discharge emitted by the PDP, that is, a pigment that absorbs a wavelength region of 800 nm to 1100 nm is used. The near-infrared transmittance of the band is preferably 20% or less, more preferably 10% or less. At the same time, it is desirable that the near-infrared absorption filter has a sufficient light transmittance in the visible light region, that is, in the wavelength region of 380 nm to 780 nm.

  Specific examples of near-infrared absorbing dyes include polymethine compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, dithiol compounds, imonium compounds, diimonium compounds, Aminium compounds, pyrylium compounds, cerium compounds, squarylium compounds, copper complexes, nickel complexes, dithiol metal complexes organic near-infrared absorbing dyes, tungsten oxide, tin oxide, indium oxide, magnesium oxide, oxidation Titanium, chromium oxide, zirconium oxide, nickel oxide, aluminum oxide, zinc oxide, iron oxide, ammonium oxide, lead oxide, bismuth oxide, inorganic near-infrared absorbing dyes such as lanthanum oxide, or a combination of two or more To be able to That.

  Moreover, as binder resin which disperse | distributes a near-infrared absorption pigment | dye, resin, such as a polyester resin, a polyurethane resin, an acrylic resin, an epoxy resin, is used. Binder resin drying and curing methods include a drying and solidification method by drying a solvent (or dispersion medium) from a solution (or emulsion), a polymerization method using energy such as heat, ultraviolet rays, and electron beams, a curing method using a crosslinking reaction, Alternatively, a curing method using a reaction such as crosslinking or polymerization between a functional group such as a hydroxyl group or an epoxy group in a resin and an isocyanate group in a curing agent can be applied.

  The neon light absorption filter that may be included in the display device according to the present invention is installed to absorb neon light emitted from the PDP, that is, an emission spectrum of neon atoms when the image light source is a plasma display panel (PDP). Is done. Since the emission spectrum band of neon light has a wavelength of 550 nm to 640 nm, the spectral transmittance of the neon light absorption filter is preferably designed to be 50% or less at a wavelength of 550 nm to 640 nm. A neon light absorption filter is a composition in which a dye conventionally used as a dye having an absorption maximum in a wavelength region of at least 550 nm to 640 nm is dispersed in a binder resin as described in the near-infrared absorption filter. It can be formed into a film, or it can be applied on a transparent substrate or other functional filter, and can be formed through drying, curing treatment or the like, if necessary. Specific examples of the dye include cyanine, oxonol, methine, subphthalocyanine or porphyrin. As the binder resin, the resins mentioned in the above-mentioned near infrared absorption filter can be used.

  The color tone adjustment filter is used to adjust the color of the display filter in order to improve the color purity of the light emitted from the panel, the color reproduction range, the display color when the power is turned off, and the like. For example, a composition in which a color tone-adjusting dye is dispersed in a binder resin is formed into a film, or this is applied on a transparent substrate or other functional filter, and is formed through drying, curing treatment, or the like as necessary. be able to. As the color tone adjusting dye, a known dye having a maximum absorption wavelength in the visible region of 380 nm to 780 nm can be used in combination with any dye according to the purpose. Examples of known dyes that can be used as the color tone adjusting dyes include the dyes described in JP 2000-275432 A, JP 2001-188121 A, JP 2001-350013 A, JP 2002-131530 A, and the like. Can be suitably used. In addition, other dyes such as anthraquinone, naphthalene, azo, phthalocyanine, pyromethene, tetraazaporphyrin, squarylium, and cyanine that absorb visible light such as yellow light, red light, and blue light. Can be used. As the binder resin, the resins mentioned in the above-mentioned near infrared absorption filter can be used.

  As an ultraviolet absorption filter, for example, a film in which a composition in which an ultraviolet absorber is dispersed in a binder resin is formed, or this is applied onto a transparent substrate or other functional filter, and dried and cured as necessary. Or the like. Examples of the ultraviolet absorber include organic compounds such as benzotriazole and benzophenone, and inorganic compounds composed of particulate zinc oxide, cerium oxide, and the like. As the binder resin, the resins mentioned in the above-mentioned near infrared absorption filter can be used.

  Next, the antireflection layer 5 will be described. The antireflection layer 5 is a layer that is disposed closest to the viewer and has a function of preventing reflection of external light. According to this, it can suppress that external light reflects on the observer side surface of the front plate 3, returns to the observer side, and what is called reflection arises and it becomes difficult to see an image | video. Such an antireflection layer 5 can be configured by using a commercially available antireflection film.

  The display device of the present invention can also include layers having various functions other than the layers described so far, depending on applications. As other layers that can be provided in the optical sheet of the present invention, those used in conventional display devices can be used without any particular limitation. Specifically, an anti-glare layer, a hard coat layer, etc. can be comprised by bonding using an adhesive layer. The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer may contain a UV absorber, a near-infrared absorber, a neon ray absorber, a toning dye, and the like, and the pressure-sensitive adhesive layer may also serve as a wavelength filter layer. The order of stacking these layers or the number of stacks is appropriately determined according to the application of the display device.

  The display device of the invention includes a plasma display panel, an optical sheet disposed on the viewer side of the plasma display panel, and a front plate disposed on the viewer side of the optical sheet. In the image display device having such a configuration, by using the optical sheet as described above as an optical sheet, the contrast of the image can be improved, and moire and ghost can be eliminated while suppressing the occurrence of Newton rings, Image clarity can also be maintained.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
(1) Production of mold for forming light transmitting portion and prism forming Grooves were cut in the circumferential direction using two types of diamond tools on a cylindrical roll having a surface plated with copper. The first diamond tool is a light transmitting portion forming tool having a tip width of 35 μm and a slope angle of 2.3 ° in the depth direction. When the depth is 91 μm, the tool width is 42 μm. The second diamond cutting tool is a triangular prism layer forming tool having a depth of 1 μm when the tip is 8 μm wide. First, using the first diamond bite, the outer periphery of the copper-plated layer of the mold roll was formed on the outer peripheral surface of the copper-plated roll at equal intervals over the entire width, with the groove pitch in the roll axis direction being 45 μm. A groove was formed by cutting. Next, using the second diamond bit, the bottoms of the grooves for 4 pitches were cut at a pitch of 8 μm and a depth of 1 μm in the roll axis direction. As a result, four triangular shapes having a groove depth of 91 μm and a groove bottom width of 35 μm and a groove bottom of 8 μm and a depth of 1 μm were formed on the metal roll, a slope angle of 2.3 °, and a mold surface width. Grooves were formed with a width of 3 μm and an opening width of 42 μm. The cross-sectional shape of a part of one groove of the roll cut as described above was as shown in FIG. The outer peripheral surface of this roll was chrome-plated to produce a light transmission portion forming die roll.

(2) Preparation of light-transmitting resin composition 40.0 parts by mass of bisphenol A-ethylene oxide 2 mol adduct, 15.0 parts by mass of isophorone diisocyanate, and bismuth tri (2-ethylhexanoate) as a urethanization catalyst (2-ethylhexanoic acid 50% solution) was mixed with 0.02 parts by mass, and reacted at 80 ° C. for 5 hours. It was made to react for a time and the photocurable prepolymer (P1) was obtained.

  Next, 60.0 parts by mass of the photocurable prepolymer (P1), 15.0 parts by mass of phenoxyethyl acrylate as the reactive diluent monomer (M1), and diacrylate obtained by adding 4 mol of bisphenol A-ethylene oxide were added. 25.0 parts by mass and 0.05 parts by mass of a phosphoric acid ester (monoester / diester = molar ratio 1/1) added with 10 mol of tetradecanol-ethylene oxide as a mold release agent (S1), and 0.05 parts by mass of 15 mol adduct of stearylamine-ethylene oxide and 3 of 1-hydroxycyclohexylphenylketone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) as a photopolymerization initiator (I1) 0.0 part by mass was mixed and homogenized to obtain a light transmissive resin composition.

The light-transmitting resin composition was applied at a thickness of 100 μm, and the resin composition was cured by irradiating an ultraviolet ray of 800 mJ / cm ² with a high-pressure mercury lamp, and a multi-wavelength Abbe refractometer DR-M4 (Atago Co., Ltd.). The refractive index of 589 nm was measured using a

(3) Formation of the light transmission part of the first optical functional layer and the prism part of the second optical functional layer Between the metal roll and the nip roll produced in the above (1), a substrate having a thickness of 100 μm A PET film (trade name: A4300, manufactured by Toyobo Co., Ltd.) was conveyed. In accordance with the conveyance of the base material, the light-transmitting resin composition obtained in the above (2) is supplied to the one surface of the base material from the supply device, and the pressing force between the mold roll and the nip roll causes the base material and The light transmitting part constituting composition was filled between the mold rolls. Thereafter, 800 mJ / cm ² of ultraviolet light was irradiated from the substrate side with a high-pressure mercury lamp to cure the light transmitting portion constituting composition, thereby forming a light transmitting portion and a prism. Thereafter, the first optical functional layer was released from the mold roll by a peeling roll, and a sheet (intermediate member) having a thickness including the light transmission portion of 205 μm ± 20 μm was produced.

  The elastic modulus of the light transmission part and the prism was measured by applying a load to the micro indenter material using a compression micro hardness tester (FISCHER HM2000) and unloading it. At this time, the load force was 100 mN, the load speed was 4 μm / 10 seconds, and the holding time was 60 seconds. As a result, the elastic modulus of the light transmission part was 800 MPa. At this time, the light transmission part and the prism had a shape corresponding to the groove of the mold roll.

(4) Preparation of resin composition for forming light absorbing portion As photocurable prepolymer (P2), ethylene oxide, 2,2 ′-[(1-methylethylidene) bis (4,1-phenyleneoxymethylene)] bis- 20.0 parts by mass of a homopolymer, 2-propenoate, 20.0 parts by mass of 2-phenoxyethyl acrylate as a reactive diluent monomer (M2), α-acryloyl-ω-phenoxypoly (oxyethylene) 20.0 parts by mass, and 13.0 parts by mass of 2- {2- [2- (acryloyloxy) (methyl) ethoxy] (methyl) ethoxy} (methyl) ethyl acrylate, and average particles as light-absorbing particles 20.0 parts by mass of acrylic crosslinked fine particles (manufactured by Ganz Kasei Co., Ltd.) containing 25% of carbon black having a diameter of 4.0 μm and a photopolymerization initiator (I2) 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.) and 7 parts by mass were mixed and homogenized to obtain a light absorbing part constituting composition.

The composition excluding the light-absorbing particles of the composition constituting the light-absorbing part was applied at a thickness of 10 μm, cured by irradiating with 800 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp, and the multi-wavelength Abbe refractometer DR- It was 1.540 when the refractive index of 589 nm was measured using M4 (made by Atago Co., Ltd.).

(5) Formation of light absorbing portion of first optical functional layer The light absorbing portion molding resin composition obtained in (4) above was supplied from a supply device onto the intermediate member prepared in (3) above. In addition, using a doctor blade disposed substantially perpendicular to the traveling direction of the intermediate member, the light absorbing portion constituting composition supplied onto the intermediate member is formed into a substantially V-shaped groove (between the light transmitting portions) formed in the intermediate member. In addition, the excess light absorbing portion constituting composition was scraped off. Thereafter, 800 mJ / cm ² of ultraviolet light was irradiated from a high pressure mercury lamp to cure the resin composition for forming a light absorption part, thereby forming a light absorption part. In this state, a recess having a depth of 3 μm was generated on the surface of the light absorbing portion.

After coating the resin except the light-absorbing particles of the same material as the light-absorbing part on the concave part on the light-absorbing part, scrape the surplus with a doctor blade and irradiate with 800 mJ / cm ² of ultraviolet rays with a high-pressure mercury lamp. When the light absorbing portion constituting composition was cured and cured, the dent was improved to 1.5 μm.

(8) Formation of pressure-sensitive adhesive layer Acrylic resin pressure-sensitive adhesive (trade name: SK Dyne 2094, Soken Chemicals Co., Ltd., 25.0% solids, solvents ethyl acetate and methyl ethyl ketone) and 100 parts by mass of a crosslinking agent ( 0.25 parts by mass of E-5XM, L-45, Soken Chemical Co., Ltd., solid content 5.0%), 0.25 parts by mass of 1,2,3-benzotriazole, and diluent (toluene / methyl ethyl ketone) /Cyclohexanone=27.69 g / 27.69 g / 4.61 g) was mixed with 32.0 parts by mass to obtain an adhesive composition. In addition, about this adhesive layer, it was 1.490 when the refractive index of 589 nm was measured using multiwavelength Abbe refractometer DR-M4 (made by Atago Co., Ltd.). Moreover, the storage elastic modulus of this adhesive layer was 0.22 MPa.

  This pressure-sensitive adhesive composition was applied to a release film (trade name: E7007, manufactured by Toyobo Co., Ltd., thickness: 38 μm) and dried, and then bonded to the substrate side surface of the first optical functional layer obtained above. In addition, an optical sheet was obtained.

(9) Evaluation of optical sheet The original optical sheet bonded to the plasma display (TH-P50G2, manufactured by Panasonic) is peeled off, and the release film is peeled off from the adhesive layer of the optical sheet obtained above instead. And it bonded to the plasma display panel. Each member was sandwiched so that the glass plate was in contact with the prism forming surface side of the optical sheet. In this state, it was visually confirmed whether Newton rings and ghosts occurred.

Example 2
An optical sheet was produced in the same manner as in Example 1 except that the prism of Example 1 was changed to a lenticular lens shape having a width of 8 μm and a depth of 1 μm, and evaluation was performed in the same manner as described above.

Comparative Example 1
In the production of the optical sheet of Example 1, an optical sheet was produced in the same manner as in Example 1 except that no prism was formed on one surface of the substrate, and evaluation was performed in the same manner as described above.

The evaluation results were as shown in Table 1 below.

DESCRIPTION OF SYMBOLS 1 Optical sheet 2 Image | video light source 3 Front plate 10 1st optical function layer 11 Base material layer 13 Light transmission part 14 Light absorption part 20 2nd optical function layer 21a Prism 21b Lenticular lens

Claims (5)

An optical sheet that is disposed between a video light source and a front plate of a video display device, and controls the incident light from the video light source to be emitted to the viewer side,
A base material layer, a plurality of light transmission parts provided on the base material layer and arranged in parallel along a sheet surface, and a plurality of light absorption parts provided in parallel between the light transmission parts. A first optical functional layer provided; and
A second optical functional layer with a prism or lenticular lens,
The optical sheet, wherein the first optical functional layer is disposed on the image light source side, and the second optical functional layer is disposed on the front plate side.   The light absorbing portion of the first optical functional layer has a substantially triangular or substantially trapezoidal cross section in the sheet thickness direction, and is arranged so that the bottom surface of the substantially triangular shape or the substantially trapezoidal lower side faces the viewer side. The optical sheet according to claim 1.   The light absorbing portion of the first optical functional layer has a substantially triangular or substantially trapezoidal shape in cross section in the sheet thickness direction, and has a shape in which a bottom surface of the substantially triangular shape or a substantially trapezoidal lower side is recessed in a concave shape. Item 3. The optical sheet according to Item 2.   It is an image display apparatus provided with the optical sheet according to any one of claims 1 to 3, wherein the top of the prism or lenticular lens of the optical sheet is arranged closer to the observer side than the optical sheet. A display device, wherein the display device is arranged with a member or a front plate through an air interface or at an interval of 5 mm or less.   The display device according to claim 4, wherein the optical member disposed closer to the viewer than the optical sheet is an antiglare layer, an antireflection layer, or a light diffusion layer.

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