JP2007078880A - Optical sheet for display, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sheet for display obtained by laminating a plurality of optical sheets with proper adhesion, and to provide its manufactured method. <P>SOLUTION: The surface of a first diffusion sheet 12 is electrified and the back of a first prism sheet 14 is superposed thereon. The surface of the first prism sheet 14 is electrified and the back of a second diffusion sheet 18 is superposed thereon. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical sheet for a display and a method for manufacturing the same, and more particularly to an optical sheet for a display that is used in a liquid crystal display element or the like and is formed by laminating a plurality of optical sheets and a method for manufacturing the same.

  In recent years, a film that diffuses light from a light source such as a light guide plate, a lens film that condenses light in the front direction, and the like are used for electronic displays such as liquid crystal display elements and organic EL.

  In this case, there are many examples in which various optical films (sheets) are laminated. For example, in Patent Document 1, a reflective polarizing film, a retardation film, and a semi-transmissive semi-reflective layer are laminated in an arbitrary order, and further, an absorptive polarizing film is laminated outside these three layers. A semi-reflective polarizing film is provided. And as many as five layers of films are interposed between the light source device and the liquid crystal cell. With this configuration, it is said that screen luminance is increased or power consumption is suppressed.

Patent Documents 2 to 4 disclose a film in which the functions of one light diffusion film and a lens film are integrated.
JP 2004-184575 A Japanese Patent Laid-Open No. 7-230001 Japanese Patent No. 3123006 JP-A-5-341132

  However, the above-mentioned films formed by laminating a plurality of films have different coefficients of thermal expansion, so that when the temperature in the liquid crystal display changes, the entire film is distorted, causing unevenness and light leakage. was there. For this reason, although it is preferable to laminate | stack in the state which weakened the adhesiveness of each film, when adhesiveness was too weak, there existed a possibility that films might peel in the post process of a lamination process, for example, a backlight unit assembly process.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical sheet for display formed by laminating a plurality of optical sheets with an appropriate degree of adhesion, and a method for manufacturing the same.

  In order to achieve the above object, the present invention provides an optical sheet for display, wherein two or more optical sheets are bonded and laminated by electrostatic force.

  To this end, the present invention provides a method for manufacturing an optical sheet for display, which is manufactured through a laminating step of charging and laminating two or more optical sheets.

  According to the present invention, since the optical sheets are charged and bonded and stacked, the optical sheets can be stacked with an appropriate degree of adhesion. Therefore, it is possible to prevent the adhesion degree from being too small and peeling off in a subsequent process, or the adhesion degree being too large to cause a problem after product assembly.

  In the present invention, the optical sheet may be a lens sheet in which convex lenses formed in one axial direction are adjacently arranged on substantially the entire surface, and a diffusion sheet laminated on the front surface or the back surface of the lens sheet. preferable.

  The “lens sheet in which convex lenses formed in one axis direction are adjacently arranged on substantially the entire surface” is typically a lenticular lens or a prism sheet, and also includes a diffraction grating and the like.

  In the present invention, the number of lens sheets is not limited to one, and two lens sheets may be laminated in a direction in which the axes of the convex lenses are substantially orthogonal.

  In the present invention, it is preferable that in the laminating step, charges of the same potential are charged on the same side when laminating a plurality of times. By charging in this way, each optical sheet can be laminated with substantially equal adhesion.

  The “same side” means that, for example, when the first optical sheet is charged on the liquid crystal panel side, the second optical sheet is charged on the liquid crystal panel side.

  According to the present invention, since two or more optical sheets are bonded and stacked by charging, the optical sheets can be stacked with an appropriate degree of adhesion. Accordingly, it is possible to prevent the optical sheets from being separated from each other during the manufacturing process, and the film to be distorted after product assembly to cause unevenness and light leakage.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, the configuration of examples (first to sixth embodiments) of optical sheets for display manufactured by the method for manufacturing optical sheets for display according to the present invention will be described, and then the method for manufacturing optical sheets for display (first) 1 to 6 manufacturing methods) will be described.

  FIG. 1 is a cross-sectional view showing a configuration of an example (first embodiment) of a display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention.

  The optical sheet for display 10 is an optical sheet module in which a first diffusion sheet 12, a first prism sheet 14, and a second diffusion sheet 18 are laminated in order from the bottom.

  The first diffusion sheet 12 and the second diffusion sheet 18 are sheets in which beads are fixed to the surface (one side) of a transparent film (support) with a binder, and have predetermined light diffusion performance. The first diffusion sheet 12 and the second diffusion sheet 18 have different bead diameters (average particle diameter), and light diffusion performances are also different.

  A resin film can be used for the transparent film (support) used for the first diffusion sheet 12 and the second diffusion sheet 18. As the material of the resin film, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic, polystyrene, polycarbonate, polyamide, PET (polyethylene terephthalate), biaxially stretched polyethylene terephthalate, Known materials such as polyethylene naphthalate, polyamideimide, polyimide, aromatic polyamide, cellulose acylate, cellulose triacetate, cellulose acetate propionate, and cellulose diacetate can be used. Of these, polyester, cellulose acylate, acrylic, polycarbonate, and polyolefin can be preferably used.

  The bead diameters of the first diffusion sheet 12 and the second diffusion sheet 18 need to be 100 μm or less, and preferably 25 μm or less. For example, the average particle size can be 17 μm within a predetermined distribution range of 7 to 38 μm.

  The first prism sheet 14 is a lens sheet in which convex lenses formed in one axial direction are adjacent and arranged on substantially the entire surface. For example, the pitch is 50 μm, the uneven height is 25 μm, and the convex portions are The apex angle can be 90 degrees (right angle).

  Various known aspects can be adopted as the material and manufacturing method of the first prism sheet 14. For example, a sheet-shaped resin material extruded from a die is placed opposite to the transfer roller that rotates at approximately the same speed as the resin material extrusion speed (a prism sheet reverse type is formed on the surface). A method for producing a resin sheet can be employed in which the pressure is sandwiched between nip roller plates rotating at the same speed and the uneven shape on the surface of the transfer roller is transferred to the resin material.

  In addition, a method of manufacturing a resin sheet in which a transfer mold plate (stamper) on which a reversal type of a prism sheet is formed and a resin plate are laminated by hot pressing and press molding by thermal transfer can be employed.

  As a resin material used in such a manufacturing method, a thermoplastic resin can be used, for example, polymethyl methacrylate resin (PMMA), polycarbonate resin, polystyrene resin, MS resin, AS resin, polypropylene resin, polyethylene resin. , Polyethylene terephthalate resin, polyvinyl chloride resin (PVC), thermoplastic elastomer, or a copolymer thereof, cycloolefin polymer, and the like.

  Further, as another manufacturing method, on the surface of the same transparent film (polyester, cellulose acylate, acrylic, polycarbonate, polyolefin, etc.) used for the first diffusion sheet 12 and the second diffusion sheet 18, A method of manufacturing a resin sheet that transfers and forms unevenness on the surface of the uneven roller (the reverse type of the prism sheet is formed on the surface) can be employed.

  More specifically, a transparent film in which an adhesive layer and a resin layer (for example, UV curable resin) are formed in two or more layers is continuously run by sequentially applying an adhesive and a resin to the surface. The transparent film is wound around a rotating concavo-convex roller, the concavo-convex surface of the concavo-convex roller is transferred to the resin layer, and the resin layer is cured in a state where the transparent film is wound around the concavo-convex roller (for example, UV irradiation). The manufacturing method of a concavo-convex sheet can be adopted. Note that no adhesive is required.

  In addition, the manufacturing method of the 1st prism sheet 14 is not necessarily limited to said example, Other manufacturing methods can also be employ | adopted if it is a method which can form desired uneven | corrugated shape on the surface.

  The sheets 12, 14, and 18 constituting the display optical sheet 10 are laminated in a state where they are adhered by electrostatic force. As will be described later, this is achieved by laminating one of the sheets 12, 14 and 18 in a charged state immediately before lamination.

  The display optical sheet 10 described above is disposed, for example, between a light source device and a liquid crystal cell, and is used so as to form a liquid crystal display element as a whole.

  Next, another example (second embodiment) of the optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to the present invention will be described. FIG. 2 is a cross-sectional view showing the configuration of the display optical sheet 20. In addition, the same code | symbol is attached | subjected about the same and similar member as FIG. 1 (1st Embodiment), and the detailed description is abbreviate | omitted.

  The display optical sheet 20 is an optical sheet in which a first diffusion sheet 12, a first prism sheet 14, a second prism sheet 16, and a second diffusion sheet 18 are laminated in order from the bottom. This display optical sheet 20 is a case where a wide diffusion performance is required.

  Similar to the first prism sheet 14, the second prism sheet 16 is a lens sheet in which convex lenses formed in one axial direction are adjacent and arranged on the substantially entire surface. For example, the pitch is 50 μm, The height of the irregularities can be 25 μm, and the apex angle of the projections can be 90 degrees (right angle). Further, the material and the manufacturing method of the second prism sheet 16 can take various known modes as with the first prism sheet 14.

  The first prism sheet 14 and the second prism sheet 16 are arranged so that the axes of the convex lenses (prisms) are substantially orthogonal to each other. That is, in FIG. 2, the axis of the convex lens of the first prism sheet 14 is arranged in a direction perpendicular to the paper surface, and the axis of the convex lens of the second prism sheet 16 is arranged in a direction parallel to the paper surface. Yes. In FIG. 2, the second prism sheet 16 is shown in a direction different from the actual direction so that it can be understood that the cross section of the second prism sheet 16 is a convex lens.

  Also in the second embodiment described above, the sheets 12, 14, 16, and 18 constituting the display optical sheet 20 are laminated in a state where they are bonded by electrostatic force. The display optical sheet 20 described above is disposed, for example, between the light source device and the liquid crystal cell, and is used so as to form a liquid crystal display element as a whole, as in the first embodiment.

  Next, still another example (third embodiment) of the optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to the present invention will be described with reference to FIG.

  The display optical sheet 30 is an optical sheet in which a diffusion sheet 12, a first prism sheet 14, and a second prism sheet 16 are laminated in order from the bottom. The second diffusion sheet 18 is omitted when a wide diffusion performance is not required as in the above-described display optical sheet 20. Also in this case, the sheets 12, 14, and 16 constituting the display optical sheet 30 are bonded by electrostatic force. As in the first embodiment, the display optical sheet 30 is disposed, for example, between a light source device and a liquid crystal cell, and is used to form a liquid crystal display element as a whole.

  Next, still another example (fourth embodiment) of a display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention will be described with reference to FIG.

  The display optical sheet 40 is an optical sheet in which the diffusion sheet 12 and the prism sheet 14 are laminated in order from the bottom. The second diffusion sheet 18 is omitted when a wide diffusion performance is not required as in the display optical sheet 10 described above, and a diffusion performance in a direction perpendicular to the paper surface as in the display optical sheet 10 described above is required. If not, the second prism sheet 16 is omitted. Also in this case, the sheets 12 and 14 constituting the display optical sheet 40 are bonded by electrostatic force. The display optical sheet 40 described above is arranged, for example, between the light source device and the liquid crystal cell and used to form a liquid crystal display element as a whole, as in the first embodiment.

  Next, another example (fifth embodiment) of the display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention will be described with reference to FIG.

  The optical sheet for display 50 is an optical sheet in which the first prism sheet 14, the second prism sheet 16, and the diffusion sheet 18 are laminated in order from the bottom. The first diffusion sheet 12 is omitted when a wide diffusion performance is not required as in the optical sheet for display 10 described above. Also in this case, the sheets 14, 16, and 18 constituting the display optical sheet 50 are bonded and laminated by electrostatic force. The display optical sheet 50 described above is disposed between the light source device and the liquid crystal cell, for example, as in the first embodiment, and used to form a liquid crystal display element as a whole.

  Next, another example (sixth embodiment) of a display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention will be described with reference to FIG.

  The display optical sheet 60 is an optical sheet in which the first prism sheet 14 and the diffusion sheet 18 are laminated in order from the bottom. The first diffusion sheet 12 is omitted when a wide diffusion performance like the above-described optical sheet for display 10 is not required, and a diffusion performance in a direction perpendicular to the paper surface like the optical sheet for display 10 described above is required. If not, the second prism sheet 16 is omitted. Also in this case, the sheets 14 and 18 constituting the display optical sheet 60 are laminated in a state where they are adhered by electrostatic force. The display optical sheet 60 described above is disposed, for example, between the light source device and the liquid crystal cell, and used to form a liquid crystal display element as a whole, as in the first embodiment.

  Next, the manufacturing method (1st, 2nd manufacturing method) of the optical sheet for displays is demonstrated. This manufacturing method can be applied in common to the above-described display optical sheets 10 to 60. However, for the convenience of description, the case where the manufacturing method is applied to a three-layer display optical sheet (first embodiment) will be described. To do.

  FIG. 7 is a configuration diagram of a display optical sheet manufacturing line 11 applied to the first manufacturing method. The rolls 12B, 14B, and 18B provided at the left end of the figure are respectively the first diffusion sheet 12, the first prism sheet 14, and the second diffusion sheet 18 shown in FIG. It is a rolled roll.

  The rolls 12B, 14B, and 18B are respectively supported by the rotation shafts of unillustrated feeding means, and the first diffusion sheet 12, the first prism sheet 14, and the second are provided by the rolls 12B, 14B, and 18B. The diffusion sheets 18 can be fed out at substantially the same speed.

  The fed first diffusion sheet 12, first prism sheet 14, and second diffusion sheet 18 are respectively supported by guide rollers G, G..., Charged by charging application devices 92 and 94, and stacked. It is like that.

  As the charging application devices 92 and 94, for example, electrode type devices are used. The charging application device 92 charges the surface (liquid crystal panel side) of the first diffusion sheet 12, and the charging application device 94 charges the surface (liquid crystal panel side) of the first prism sheet 14. is there. The charging devices 92 and 94 are preferably charged to the same electrode side. For example, when the surface of the first diffusion sheet 12 is positively charged, the surface of the first prism sheet 14 is also positively charged. Like that. Further, when the surface of the first diffusion sheet 12 is negatively charged, the surface of the first prism sheet 14 is also negatively charged. Furthermore, it is preferable that the charging devices 92 and 94 are controlled so that the charge amount charged to the first diffusion sheet 12 is equal to the charge amount charged to the first prism sheet 14. For measurement of the charge amount, it is preferable to use an electrostatic potential measuring device (not shown), and for example, control is performed so that charging is performed at 1 kV.

  FIG. 8A to FIG. 8C are explanatory diagrams for explaining the stacking process. In the laminating step, first, as shown in FIG. 8A, the surface of the first diffusion sheet 12 is positively charged at 1 kV by the charging application device 92. In this state, the back surface of the first prism sheet 14 is immediately superimposed on the surface of the first diffusion sheet 12. As a result, as shown in FIG. 8B, the surface of the first diffusion sheet 12 and the back surface of the first prism sheet are laminated in a state where they are adhered by electrostatic force.

  Next, as shown in FIG. 8C, the surface of the first prism sheet 14 is positively charged with 1 kV by the charging application device 94. In this state, the second diffusion sheet 18 is immediately superimposed on the surface of the first prism sheet 14. Thereby, the surface of the first prism sheet 14 and the back surface of the second diffusion sheet 18 are laminated in a state where they are adhered by electrostatic force. Although FIGS. 8A to 8C show an example in which the charge is positive, the charge may be negative.

  Thus, by charging and laminating the surface of the first diffusion sheet 12 and the back surface of the first prism sheet 14, and the surface of the first prism sheet 14 and the back surface of the second diffusion sheet 18, The 1st diffusion sheet 12, the 1st prism sheet 14, and the 2nd diffusion sheet 18 can be laminated with appropriate adhesion (lamination process). Here, the appropriate degree of adhesion is an degree of adhesion that does not peel until the assembly process when commercialized, and that the sheets 12, 14, and 18 can be appropriately peeled after commercialization.

  The laminated body thus laminated is sent to the punching press device 48. The punching press device 48 is a device that cuts the periphery of the laminate into a product size. By punching with this punching press device 48, the optical sheet 10 for display in which the sheets 12, 14, 18 are bonded by charging is obtained. The blade of the punching press device 48 is preferably a non-conductive material such as ceramic.

  Through the above steps, the optical sheet for display 10 (see FIG. 1) is formed. The laminated and cut display optical sheets 10 are conveyed onto the conveyor 26 and stopped. The optical sheets for display 10 on the conveyor 26 are sequentially stacked on the stacking device 32 by the suction lateral transfer device 28. On the other hand, the sheet laminate 34 punched out by the punching press 48 is taken up by a take-up roll 36 of the take-up device.

  As described above, according to the manufacturing method of the present embodiment, the sheets 12, 14, and 18 are laminated with an appropriate degree of adhesion because the charge is charged and the lamination is performed. Therefore, the sheets 12, 14, and 18 are not peeled off in the process until commercialization, for example, the backlight unit assembly process. Moreover, even if it is a case where a big temperature change is received after commercialization, each sheet | seat 12,14,18 can be peeled and there is no possibility that the optical sheet 10 for a display may be distorted. That is, since the first prism sheet 14 and the first and second diffusion sheets 12 and 18 have different coefficients of thermal expansion, if the sheets 12, 14 and 18 are firmly bonded, a large temperature change is applied to the display. Although the optical sheet 10 may be distorted, in the present embodiment, the sheets 12, 14, and 18 are in close contact due to charging, and thus the sheets 12, 14, and 18 are peeled before the display optical sheet 10 is distorted. Therefore, the optical sheet for display 10 can be prevented from being distorted, and there is no possibility that unevenness or light leakage due to the distortion occurs. As described above, according to the manufacturing method of the present embodiment, the sheets 12, 14, and 18 can be laminated with an appropriate degree of adhesion, and the sheets 12, 14, and 18 are peeled off before commercialization. It is possible to prevent the display optical sheet 10 from being distorted after conversion.

  Next, another manufacturing method (second manufacturing method) of the optical sheet for display will be described. FIG. 9 is a configuration diagram of a display optical sheet manufacturing line 21 applied to the second manufacturing method. In addition, the same code | symbol is attached | subjected about the member similar to the optical sheet manufacturing line 11 for a display of FIG. 7, and the detailed description is abbreviate | omitted.

  The display optical sheet manufacturing line 21 in FIG. 9 is different in the stacking order from the manufacturing line 11 in FIG. That is, the display optical sheet production line 21 first laminates the surface of the first prism sheet 14 on the back surface of the second diffusion sheet 18 and then the first diffusion sheet 12 on the back surface of the first prism sheet 14. Laminate the surface. At that time, the back surface of the second diffusion sheet 18 is charged by the charging device 94 and the back surface of the first prism sheet 14 is charged by the charging device 92. Therefore, the lamination process is performed as shown in FIGS. 10 (a) to 10 (c).

  First, as shown in FIG. 10A, the back surface of the second diffusion sheet 18 is positively charged at 1 kV by the charging application device 94. In this state, the surface of the first prism sheet 14 is immediately superimposed on the back surface of the second diffusion sheet 18. Thus, as shown in FIG. 10B, the back surface of the second diffusion sheet 18 and the surface of the first prism sheet 14 are laminated in a state where they are adhered by electrostatic force.

  Next, as shown in FIG. 10C, the back surface of the first prism sheet 14 is positively charged at 1 kV by the charging application device 92. In this state, the surface of the first diffusion sheet 12 is immediately overlaid on the back surface of the first prism sheet 14. Thereby, the back surface of the first prism sheet 14 and the front surface of the first diffusion sheet 12 are laminated in a state where they are adhered by electrostatic force. 10A to 10C show an example in which the charging is positive, but the charging may be negative.

  Even when the laminating process is performed in the order as described above, the sheets 12, 14, and 18 are bonded by electrostatic force, so that the sheets 12, 14, and 18 are stacked with an appropriate degree of adhesion. Therefore, it can prevent that each sheet | seat 12, 14, 18 peels before commercialization, or the optical sheet 10 for a display is distorted after commercialization.

  In addition, although embodiment mentioned above is an example of the manufacturing method of the optical sheet 10 for a three-layer display which consists of the 1st diffusion sheet 12, the 1st prism sheet 14, and the 2nd diffusion sheet 18, it is from four layers. Can be applied to a display optical sheet (for example, the display optical sheet 20 of the second embodiment), and in this case as well, the sheets 12, 14, 16, and 18 before lamination are charged. By doing so, each sheet | seat 12, 14, 16, 18 can be laminated | stacked by appropriate adhesiveness. In that case, between the sheets having the same thermal expansion coefficient, one side or four sides may be firmly bonded (or joined).

  In the above-described embodiment, the sheets 12, 14, and 18 are bonded only by electrostatic force, but only a part (one point, several points, or one side) of each sheet 12, 14, and 18 is bonded. It may be. As a bonding method, for example, it is preferable to bond the sheets 12, 14, and 18 by discharging an adhesive from a dispenser or the like. The adhesive at that time is preferably an adhesive that is bonded with the aid of heat or a catalyst, specifically, a silicon-based adhesive, a polyurethane-based adhesive, a polyester-based adhesive, an epoxy-based adhesive, Common adhesives such as cyanoacrylate adhesives and acrylic adhesives can be used. Among these, epoxy adhesives are excellent in strength and heat resistance, and can be suitably used. Since the cyanoacrylate adhesive is excellent in immediate effect and strength, it can be used for the production of an efficient optical sheet for display. Polyester adhesives are particularly suitable because they are excellent in strength and processability. Furthermore, these adhesives are roughly classified into a thermosetting type, a hot melt type, and a two-component mixed type depending on the bonding method, and a thermosetting type or a hot melt type capable of continuous production is preferably used. Whatever adhesive is used, the coating thickness is preferably 0.5 μm to 50 μm.

  As another joining method, you may make it join each sheet | seat 12,14,18 with a double-sided tape. In this case, the double-sided tape is one in which a pressure-sensitive adhesive is applied to both sides, and as the pressure-sensitive adhesive, a highly adhesive acrylic copolymer resin can be used, but other than that, for example, silicon-based, natural rubber-based, A synthetic rubber-based pressure-sensitive adhesive can be used, and an acrylic pressure-sensitive adhesive is preferably used in consideration of physical strength such as heat resistance and creep resistance, price, and the like.

  As another joining method, the sheet may be fused by oscillating ultrasonic waves. In that case, as a device that oscillates ultrasonic waves, there are known devices that raise and lower the horn with an air cylinder and those that raise and lower the horn with a servo motor. Any type of ultrasonic welding apparatus can be applied as long as the sheets can be welded together. In addition, the setting conditions for oscillating the ultrasonic wave may be determined within a range in which the fused portion is not melted by heat. If necessary, the bonded portion is bonded by an air cooling mechanism such as air blowing after bonding (fusion). It may be cooled.

  As another joining method, each sheet 12, 14, 18 may be joined by irradiating a laser. In this case, the laser setting conditions may be determined within a range in which the fused portion is not melted by heat. If necessary, the bonded portion may be cooled by an air cooling mechanism such as air blowing after bonding (fusion). Good.

Sectional drawing of embodiment of the optical sheet for a display manufactured by the manufacturing method of the optical sheet for a display which concerns on this invention Sectional drawing of other embodiment of the optical sheet for displays Sectional drawing of other embodiment of the optical sheet for a display. Sectional drawing of other embodiment of the optical sheet for a display. Sectional drawing of other embodiment of the optical sheet for a display. Sectional drawing of other embodiment of the optical sheet for a display. Configuration diagram of optical sheet manufacturing line for display applied to first manufacturing method Sectional view schematically showing the lamination process Configuration diagram of optical sheet production line for display applied to second production method Sectional view schematically showing the lamination process

Explanation of symbols

  10, 20, 30, 40, 50, 60 ... optical sheet for display, 12 ... first diffusion sheet, 14 ... first prism sheet, 16 ... second prism sheet, 18 ... second diffusion sheet, 92 94. Charge applying device

Claims (4)

  A method for producing an optical sheet for display, comprising producing a laminate through charging and laminating two or more optical sheets.   The optical sheet is a lens sheet in which convex lenses formed in one axial direction are adjacent to each other and arranged on substantially the entire surface, and a diffusion sheet laminated on the front surface and / or the back surface of the lens sheet. Manufacturing method of optical sheet for display.   3. The method for producing an optical sheet for display according to claim 1, wherein the laminating step charges the same electric charge on the same side when laminating a plurality of times.   An optical sheet for a display, wherein two or more optical sheets are bonded and laminated by electrostatic force.

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