JP2007155941A - Optical sheet for display, method for manufacturing the same, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sheet for a display that is free of deposition of dust or foreign matters, and has a reduced number of bright spots. <P>SOLUTION: A layered body 200 is formed by layering a first diffusion sheet, a first prism sheet, a second prism sheet and a second diffusion sheet. After the layered body 200 has been cut out into an optical sheet for a display, the layered body 200 is cleaned by a cleaning device 92. The cleaning device 92 is equipped with adhesive rollers 205 to 208. Each adhesive roller 205 to 208 removes dust or foreign substances that has deposited on the top surface (by roller 205), the rear face (by roller 206) and both side faces (by rollers 207, 208) of the layered body 200. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical sheet for display, a method for manufacturing the same, and an image display device, and in particular, for manufacturing a laminate of sheet-like materials used for liquid crystal display elements and the like at a low cost by a simpler process than before. The present invention relates to a suitable optical sheet for display, a method for manufacturing the same, and an image display device configured using the optical sheet for display.

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, the screen brightness is increased or the 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, in the above-described conventional configuration, it is required to go through a number of processes in order to laminate a number of layers of film, which complicates the process and inevitably increases the cost. Further, since the surface of a flat lens such as a lenticular lens or a prism sheet is easily damaged or dirty, it is generally delivered in a state where a protective sheet is stuck on the surface. However, such a protective sheet is only discarded after being peeled from the flat lens, and is not preferable because it is not only a waste of resources but also increases costs. Moreover, the operation | work which peels a protective sheet from a flat lens is required, and will also reduce productivity by that much. Further, when the protective sheet is peeled off from the flat lens, contamination such as dust is easily attached to the flat lens by peeling charging, and there are many problems in terms of quality.

  Also, when laminating multiple layers of films (sheets), the film tends to be damaged due to rubbing during lamination, rubbing due to thermal expansion / shrinkage, rubbing due to handling, and the like. Furthermore, in order to correct defects (distortion, curl, etc.) due to mismatching due to thermal expansion / contraction between multiple films, measures such as increasing the thickness of individual films (such as increasing rigidity) must also be required. There are many demerits such as design restrictions and cost increase. Furthermore, with the recent increase in size and miniaturization of image display devices, there is a great demand for reduction of dust and foreign substances adhering to various optical films.

  The present invention has been made in view of such circumstances, and can greatly reduce dust, foreign matter, and the like attached when manufacturing an optical sheet for display used for display applications such as liquid crystal display elements. An object of the present invention is to provide an optical sheet for display and a method for manufacturing the same, in which the bright spot is reduced and the productivity is improved, and an image display device configured using the optical sheet for display.

  In order to achieve the above object, the invention according to claim 1 is characterized in that at least one prism sheet in which convex lenses formed in a uniaxial direction are arranged adjacent to each other on substantially the entire surface, and at least one sheet that irregularly reflects light. In the method for manufacturing an optical sheet for display, comprising: a joining step for forming a laminate by supplying each of the diffusion sheets; and a cutting step for cutting the optical sheet for display from the laminate, before the cutting step And a first cleaning step of cleaning at least one of the prism sheet, the diffusion sheet or the laminate. According to the first aspect, since the prism sheet, the diffusion sheet, or the laminated body is cleaned, dust and foreign matters attached to them are reduced. Therefore, the bright spot of the obtained optical sheet for display can be reduced, and productivity can be improved.

  In order to achieve the above object, the invention according to claim 2 is characterized in that at least one prism sheet in which convex lenses formed in a uniaxial direction are adjacently arranged on substantially the entire surface, and at least one sheet that irregularly reflects light. In the method for producing an optical sheet for display, comprising: a diffusion sheet; and a bonding step for forming a laminate by cutting each of the diffusion sheets; and a cutting step for cutting the optical sheet for display from the laminate, after the cutting step, It has the 2nd cleaning process which cleans the said optical sheet for displays. Manufacturing method of optical sheet for display. According to the second aspect, since the display optical sheet is cleaned, dust and foreign matters adhering to the optical sheet are reduced. Therefore, the bright spot of the obtained optical sheet for display can be reduced, and productivity can be improved.

  According to a third aspect of the present invention, it is preferable to have a first cleaning step for cleaning at least one of the prism sheet, the diffusion sheet, or the laminate before the cutting step. According to the third aspect, since the prism sheet, the diffusion sheet, the laminate, and the display optical sheet are cleaned, dust and foreign matters adhering to them are extremely reduced. For this reason, the bright spot of the obtained optical sheet for display is extremely reduced, and the productivity is extremely improved.

  In the invention of claim 4, it is preferable that the diffusion body has one diffusion sheet formed on one surface side of at least one prism sheet.

  In the invention of claim 5, it is preferable that another diffusion sheet is formed on the opposite side of the one surface of the at least one prism sheet.

  In a sixth aspect of the invention, it is preferable that at least one of the prism sheet, the diffusion sheet, and the laminate is cleaned using a cleaning means provided in the first cleaning step or the second cleaning step.

  In the invention of claim 7, it is preferable that the cleaning means is provided on at least one surface, back surface, and both side surfaces of the prism sheet, the diffusion sheet, or the laminate, and cleans at least one surface.

  In the invention of claim 8, it is preferable that the cleaning means is an adhesive roller.

  In the invention of claim 9, it is preferable that the joining step is a step of joining the lens sheet and the diffusion sheet at at least one place on the periphery thereof.

  The invention of claim 10 is an optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to any one of claims 1 to 9, in order to achieve the above object. According to the tenth aspect, since the prism sheet, the diffusion sheet, the laminate, and the display optical sheet are cleaned, dust and foreign matters adhering to them are reduced. Therefore, the bright spot of the optical sheet for display is reduced and the productivity is improved.

  An eleventh aspect of the present invention is an image display device using the optical sheet for display according to the tenth aspect to achieve the above object.

  As described above, according to the present invention, the optical sheet for display, the manufacturing method thereof, and the display in which the adhesion of dust, foreign matter, etc. is suppressed, the bright spots are reduced, and the productivity is improved. An image display device constituted by using the optical sheet for use is obtained.

  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, a second prism sheet 16, and a second diffusion sheet 18 are laminated in order from the bottom. is there.

  The first diffusion sheet 12 and the second diffusion sheet 18 are sheets in which beads 13 and 19 are fixed to a surface (one side) of a transparent film (support) with a binder, and have a predetermined light diffusion performance. The first diffusion sheet 12 and the second diffusion sheet 18 have different diameters (average particle diameters) of the first beads 13 and the second beads 19 and also have different light diffusion performance.

  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 diameters of the beads 13 and 19 of the first diffusion sheet 12 and the second diffusion sheet 18 are required 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 and the second prism sheet 16 are lens sheets in which convex lenses 14A and 16A formed in one axial direction are adjacently arranged on substantially the entire surface. The apex angle of the convex portion can be 90 degrees (right angle).

  The first prism sheet 14 and the second prism sheet 16 are arranged in a direction in which the axes of the convex lens (prism) 14A and the convex lens (prism) 16A are substantially orthogonal. That is, in FIG. 1, the axis of the convex lens 14A of the first prism sheet 14 is arranged in a direction perpendicular to the paper surface, and the axis of the convex lens 16A of the second prism sheet 16 is arranged in a direction parallel to the paper surface. Yes. In FIG. 1, 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.

  The material and manufacturing method of the first prism sheet 14 and the second prism sheet 16 can take various known modes. 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.

  As another manufacturing method, an uneven roller is formed on the surface of a transparent film (polyester, cellulose acylate, acrylic, polycarbonate, polyolefin, etc.) similar to that used for the first diffusion sheet 12 and the second diffusion sheet 18. It is possible to employ a resin sheet manufacturing method in which surface irregularities are transferred and formed (an inverted type of a prism sheet is formed on the surface).

  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 and the 2nd prism sheet 16 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.

  As shown in FIG. 1, the left and right end portions of the display optical sheet 10 are integrated with each other by a joint portion 10 </ b> A. The joining portion 10A is formed by carbon dioxide laser processing or the like in the joining process.

  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 (= image display device) as a whole. In this case, in addition to the various merits already described (the optical sheet for display can be manufactured at a low cost and high quality with a simpler process than before), the assemble work of the liquid crystal display element is also very easy. can get.

  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 diffusion sheet (= first 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 optical sheet for display 10 described above. As in the display optical sheet 10 of FIG. 1, the left and right end portions of the display optical sheet 20 are integrated with each other through a joint 20 </ b> A. The joining portion 20A is formed by carbon dioxide laser processing or the like in the joining process.

  The display optical sheet 20 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 (= image display device) as a whole. The

  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. FIG. 3 is a cross-sectional view showing a configuration of the display optical sheet 30. In addition, the same code | symbol is attached | subjected about the same and similar member as FIG. 1 (1st Embodiment) and FIG. 2 (2nd Embodiment), and the detailed description is abbreviate | omitted.

  The display optical sheet 30 is an optical sheet in which the first diffusion sheet 12, the prism sheet 14, and the second diffusion sheet 18 are laminated in order from the bottom. The optical sheet for display 30 is the one in which the second prism sheet 16 is omitted when the diffusion performance in the direction perpendicular to the paper surface like the optical sheet for display 10 described above is not required. As in the display optical sheet 10 of FIG. 1, the left and right end portions of the display optical sheet 30 are integrated with each other through a joint 30 </ b> A. The bonding portion 30A is formed by carbon dioxide laser processing or the like in the bonding process.

  The display optical sheet 30 described above is disposed, for example, between the light source device and the liquid crystal cell, as in the first and second embodiments, and forms a liquid crystal display element (= image display device) as a whole. Used to be.

  Next, still another example (fourth embodiment) of the display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention will be described. FIG. 4 is a cross-sectional view showing a configuration of the display optical sheet 40. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 1 (1st Embodiment), FIG. 2 (2nd Embodiment), etc., and the detailed description is abbreviate | omitted. 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 like the above-described optical sheet for display 10 is not required, and the diffusion performance in the direction perpendicular to the paper surface like the optical sheet for display 10 described above is required. The second prism sheet 16 is omitted when not present. As in the display optical sheet 10 of FIG. 1, the left and right ends of the display optical sheet 40 are integrated with each other by a joint 40 </ b> A. The joint 40A is formed by carbon dioxide laser processing or the like in the joining process.

  The display optical sheet 40 described above is disposed, for example, between the light source device and the liquid crystal cell, as in the first to third embodiments, and forms a liquid crystal display element (= image display device) as a whole. Used for.

  Next, another example (fifth embodiment) of a display optical sheet manufactured by the method for manufacturing a display optical sheet according to the present invention will be described. FIG. 5 is a cross-sectional view showing the configuration of the display optical sheet 50. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 1 (1st Embodiment), FIG. 2 (2nd Embodiment), etc., and the detailed description is abbreviate | omitted. The display optical sheet 50 is an optical sheet in which a first prism sheet 14, a second prism sheet 16, and a diffusion sheet (= second 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. As in the display optical sheet 10 of FIG. 1, the left and right end portions of the display optical sheet 50 are integrated with each other through a joint 50 </ b> A. The joining portion 50A is formed by carbon dioxide laser processing or the like in the joining process.

  The display optical sheet 50 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 (= image display device) as a whole, as in the first embodiment. The

  Next, another example (sixth 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. 6 is a cross-sectional view showing a configuration of the display optical sheet 60. In addition, the same code | symbol is attached | subjected about the member similar to FIG. 1 (1st Embodiment), FIG. 2 (2nd Embodiment), etc., and the detailed description is abbreviate | omitted. The display optical sheet 60 is an optical sheet in which a first prism sheet 14 and a diffusion sheet (= second diffusion sheet) 18 are laminated in order from the bottom. The first diffusion sheet 12 is omitted when a wide diffusion performance such as the above-described optical sheet for display 10 is not required, and a diffusion performance in a direction perpendicular to the paper surface such as the above-described optical sheet for display 10 is required. The second prism sheet 16 is omitted when not present. As in the display optical sheet 10 of FIG. 1, the left and right end portions of the display optical sheet 60 are integrated with each other through a joint 60 </ b> A. The joint 60A is formed by carbon dioxide laser processing or the like in the joining process.

  The display optical sheet 60 described above is disposed, for example, between the light source device and the liquid crystal cell, as in the first to fifth embodiments, and forms a liquid crystal display element (= image display device) as a whole. Used for.

  Next, the manufacturing method (1st-6th manufacturing method) of the optical sheet for displays is demonstrated. This manufacturing method can be commonly applied 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 four-layer display optical sheet (first embodiment) will be described. To do.

  FIG. 7 is a configuration diagram of a display optical sheet manufacturing line 70 applied to the first manufacturing method. The rolls 72, 74, 76, 78 provided at the left end of the figure are respectively the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion shown in FIG. A roll around which the sheet 18 is wound.

  These rolls 72, 74, 76, and 78 are respectively supported on the rotation shafts of the unillustrated feeding means, and the first diffusion sheet 12, the first prism sheet 14, and the second prism are supported by the rolls 72, 74, 76, and 78. The sheet 16 and the second diffusion sheet 18 can be fed at substantially the same speed. The sheets 12, 14, 16, and 18 are cleaned on the front and back surfaces by the cleaning devices 73, 75, 77, and 79 immediately after being fed out, and dust, foreign matter, etc. adhering to the front and back surfaces are removed. Removed. The cleaning devices 73, 75, 77, and 79 are not particularly limited, but it is preferable to use an adhesive roll.

  The fed first diffusion sheet 12, first prism sheet 14, second prism sheet 16 and second diffusion sheet 18 are supported by guide rollers 80 to 85, respectively, and finally upstream of a laser head 90 described later. The laminated body 200 is laminated on the side (joining step). The laminate 200 will be described later.

  As a laser beam irradiation apparatus including the laser head 90, a YAG laser irradiation apparatus having a wavelength of 355 nm to 1064 nm, a semiconductor laser irradiation apparatus, a carbon dioxide laser irradiation apparatus having a wavelength of 9 μm to 11 μm, and the like can be employed. The oscillation method may be continuous oscillation or pulse oscillation. However, in order to perform welding at approximately the same time as cutting, doting by pulse oscillation is preferable because the appearance is good.

  The output and frequency required to perform welding (joining process) almost simultaneously with the cutting (cutting process) vary depending on the feed speed of the material, the scanning speed of the laser beam, the thickness of the material, etc. Good welding results can be obtained under the conditions of 50 W and a frequency of 100 kHz or less.

  The laser head 90 is attached to an X drive robot axis or an XY drive robot axis (not shown) that can move in the X direction (sheet width direction) or XY direction, and performs positioning to an arbitrary position and arbitrary trajectory movement. be able to. The entire laser head 90 may be moved according to the irradiation pattern of the laser beam, but the laser head 90 is placed separately (fixed), and only the laser beam is guided by the optical fiber to simplify the moving mechanism in the XY directions. You can also

  It is also possible to provide a known mechanism (a suction device or the like) that sucks smoke generated at the time of cutting by the laser head 90 and welding.

  Laser light is irradiated from the laser head 90 to the cut and bonded portions on the periphery of the laminate, and the periphery of the laminate 200 is cut into a product size and melted and joined while moving the irradiation spot at a constant speed. Then, the cut laminated body 200 is passed through the cleaning device 92 to remove dust, foreign matter and the like attached to the front and back surfaces. The cleaning device 92 is not particularly limited, but an adhesive roll is preferably used. The adhesive roll may be disposed and cleaned on at least one of the front surface, back surface, and both side surfaces of the laminate 200. However, in the present invention, it is most preferable that the adhesive roll as the cleaning device 92 is disposed on all of the front surface, the back surface, and both side surfaces of the laminate 200 to clean each surface to remove dust, foreign matter, and the like. preferable.

  Through the above steps, the optical sheet for display 10 (see FIG. 1) is formed. The cut and bonded display optical sheet 10 is conveyed onto the conveyor 94 and stopped. The display optical sheets 10 on the conveyor 94 are sequentially stacked on the stacking device 98 by the suction lateral transfer device 96.

  On the other hand, the sheet-launched laminated body 100 from which the optical sheet 10 for display is punched by the laser head 90 is wound around a winding roll 104 of a winding device (not shown in detail) while being supported by a guide roller 102.

  According to the above-described optical sheet manufacturing method (first manufacturing method), the following effects 1) to 3) can be obtained.

1) Scratch failure reduction effect If the upper and lower surfaces of the lens sheets (the first prism sheet 14 and the second prism sheet 16) are scratched, the scratches are conspicuous because of the lens effect. On the other hand, when the bottom surface of the diffusion sheet (the first diffusion sheet 12 or the second diffusion sheet 18) is scratched, the scratches are not noticeable because the light is diffused. For this reason, preventing damage to the lens sheet leads to reduction of scratch failure. Although scratches are often attached during handling after sheet processing, since the diffusion sheet serves as a protective sheet by combining the lens sheet with the diffusion sheet, failure due to scratches can be reduced. In particular, the effect is great in the display optical sheet 10 (see FIG. 1) of the first embodiment and the display optical sheet 30 (see FIG. 3) of the third embodiment in which the lens sheet does not appear on the surface.

2) Effect of reducing assembly man-hour For example, when the optical sheet for display 10 of the first embodiment (see FIG. 1) is used in the assembly of the liquid crystal display element, the assembly man-hour is only one process for incorporating the optical sheet for display 10. On the other hand, when the conventional product is used, the first diffusion sheet is incorporated ⇒ the first lens sheet is removed from the back surface protective sheet ⇒ the first lens sheet is removed from the surface protective sheet ⇒ the first lens sheet is incorporated ⇒ Eight steps are required: removal of the rear surface protection sheet of the lens sheet 2 ⇒ removal of the surface protection sheet of the second lens sheet ⇒ incorporation of the second lens sheet ⇒ incorporation of the second diffusion sheet. Thus, according to the first manufacturing method, a significant reduction in assembly man-hours can be achieved, and the product cost can be reduced.

3) Reduction effect of protective sheet In many cases, a protective sheet is attached to the front and back of a lens sheet to prevent scratches. This protective sheet is discarded after the lens sheet is assembled, and is very wasteful. The product of the present invention can save the protective sheet by using the diffusion sheet as a protective sheet.

  Specifically, one protective sheet can be reduced in the display optical sheet 40 (see FIG. 4) of the fourth embodiment and the display optical sheet 60 (see FIG. 6) of the sixth embodiment. Two protective sheets can be reduced in the display optical sheet 30 (see FIG. 3), and the display optical sheet 20 in the second embodiment (see FIG. 2) and the display optical sheet 50 in the fifth embodiment (see FIG. 5). The number of protective sheets can be reduced by 3, and the number of protective sheets can be reduced by 4 in the display optical sheet 10 of the first embodiment (see FIG. 1).

  Next, another manufacturing method (second manufacturing method) of the optical sheet for display will be described. FIG. 8 is a configuration diagram of a display optical sheet production line 110 applied to the second production method. In addition, the same code | symbol is attached | subjected about the member similar to the optical sheet manufacturing line 70 for display of FIG. 7 (1st manufacturing method), and the detailed description is abbreviate | omitted.

  In the display optical sheet production line 110, dispensers 112, 114, 116 and a punching press device 118 are employed instead of the laser head 90 of the display optical sheet production line 70.

  The dispensers 112, 114, and 116 are supply devices that discharge the adhesive from the tip. The dispenser 112 supplies an adhesive to the surface of the first diffusion sheet 12 in order to bond the first diffusion sheet 12 and the first prism sheet 14, and the dispenser 114 includes the first prism sheet 14 and the first prism sheet 14. In order to bond the two prism sheets 16, an adhesive is supplied to the surface of the first prism sheet 14, and the dispenser 116 is used to bond the second prism sheet 16 and the second diffusion sheet 18. An adhesive is supplied to the surface of the second prism sheet 16.

  The adhesive supplied from the dispensers 112, 114, 116 is preferably an adhesive that is bonded with the aid of heat or a catalyst. Specifically, general adhesives such as silicon adhesives, polyurethane adhesives, polyester adhesives, epoxy adhesives, cyanoacrylate adhesives, and acrylic adhesives can be used.

  Since the display optical sheets 10 to 60 may be used at high temperatures, an adhesive that is stable even at room temperature to 120 ° C. is preferable. 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.

  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.

  Further, it is preferable to provide a drying means for drying the adhesive between the downstream guide rollers 85. The drying means is not particularly limited, and examples include known drying methods such as drying with warm air or hot air, drying with dehumidified air, and the like.

  The dispensers 112, 114, and 116 are attached to an X drive robot axis or an XY drive robot axis (not shown) that can move in the X direction (sheet width direction) or XY direction, and perform positioning to an arbitrary position and arbitrary trajectory movement. Be able to.

  Adhesive is supplied from these dispensers 112, 114, and 116 to the joining portion at the periphery of the laminate, and the periphery of the laminate 202 is joined by the downstream guide roller 85 while transporting the laminate 202. The punching press device 118 downstream of the dispensers 112, 114, and 116 is a device that cuts the periphery of the laminate 202 into a product size. In the punching press device 118, the blade is inserted into the center portion of the bonded portion, so that all the pieces of the punched sheet (display optical sheets 10 to 60) or only the end portions of the arbitrary pieces are bonded. The obtained composite sheet can be obtained. Then, the laminated body 202 cut in the same manner as the display optical sheet manufacturing line 70 of FIG. 7 is passed through the cleaning device 92 to remove dust, foreign matter, and the like adhering to the front and back surfaces.

  Next, still another manufacturing method (third manufacturing method) of the optical sheet for display will be described. FIG. 9 is a configuration diagram of a display optical sheet production line 130 applied to the third production method. In addition, the same code | symbol is attached about the same or similar member as the optical sheet manufacturing line 70 for display of FIG. 7 (1st manufacturing method) and the optical sheet manufacturing line 110 for display of FIG. 8 (2nd manufacturing method). A detailed description thereof will be omitted.

  In the display optical sheet production line 130, tape feeders 132, 134, and 136 are employed instead of the dispensers 112, 114, and 116 in the display optical sheet production line 110. Each of these tape supply devices 132, 134, and 136 is a supply device that supplies double-sided tape from the tip.

  The tape supply device 132 supplies double-sided tape to the surface of the first diffusion sheet 12 in order to bond the first diffusion sheet 12 and the first prism sheet 14, and the tape supply device 134 includes the first prism. In order to bond the sheet 14 and the second prism sheet 16, a double-sided tape is supplied to the surface of the first prism sheet 14. The tape supply device 136 includes a second prism sheet 16, a second diffusion sheet 18, and the like. In order to bond the two, a double-sided tape is supplied to the surface of the second prism sheet 16.

  The double-sided tape supplied from the tape supply devices 132, 134, and 136 is one in which an adhesive is applied on both sides. As the adhesive for the double-sided tape, a highly adhesive acrylic copolymer resin can be used. However, other adhesives such as silicone, natural rubber, and synthetic rubber can be used, and heat resistance and creep resistance can be used. It is preferable to use an acrylic pressure-sensitive adhesive if the physical strength such as the above, the price, etc. are comprehensively considered.

  The tape supply devices 132, 134, and 136 that supply the double-sided tape can be handled by using a commercially available general-purpose tape dispenser. The tape supply devices 132, 134, and 136 are attached to a single-axis moving mechanism (not shown) that can be moved to an arbitrary position in the X direction (sheet width direction). Can be varied.

  In addition, a pivot mechanism (not shown) is provided at a fixed portion of the tape supply devices 132, 134, and 136, and the positions of the tape supply devices 132, 134, and 136 are changed in synchronization with the feeding speeds of the sheets 72, 74, and 76. Thus, the mechanism can cope with a tape application pattern in an oblique direction.

  In the punching press device 118 downstream of the tape supply devices 132, 134, and 136, the punched sheet (display optical sheets 10 to 60) is formed by allowing the blade to enter the central portion of the bonded tape width portion. It is possible to obtain a composite sheet in which all the pieces or only the end portions of any piece are bonded. Then, the laminated body 202 cut in the same manner as the display optical sheet manufacturing line 70 of FIG. 7 is passed through the cleaning device 92 to remove dust, foreign matter, and the like adhering to the front and back surfaces.

  Next, still another manufacturing method (fourth manufacturing method) of the display optical sheet will be described. FIG. 10 is a configuration diagram of a display optical sheet manufacturing line 150 applied to the fourth manufacturing method. 7 (first manufacturing method), the display optical sheet manufacturing line 70, FIG. 8 (second manufacturing method), the display optical sheet manufacturing line 110, and FIG. 9 (third manufacturing method), the display. Members that are the same as or similar to those in the optical sheet manufacturing line 130 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  In the display optical sheet production line 150, ultrasonic horns 152, 154, and 156 are employed instead of the dispensers 112, 114, and 116 in the display optical sheet production line 110. The ultrasonic horns 152, 154, and 156 are arranged on the downstream side of the guide rollers 83, 84, and 85, respectively.

  The ultrasonic horns 152, 154, and 156 are devices for fusing two or more stacked sheets. That is, the ultrasonic horn 152 fuses the first diffusion sheet 12 and the first prism sheet 14, and the ultrasonic horn 154 fuses the first prism sheet 14 and the second prism sheet 16. The ultrasonic horn 156 is for fusing the second prism sheet 16 and the second diffusion sheet 18 together.

  Ultrasonic horns (= ultrasonic welding devices) 152, 154, and 156 are conventionally known, such as a type that raises and lowers the horn with an air cylinder and a type that raises and lowers the horn with a servo motor. However, any type of ultrasonic welding apparatus can be applied as long as the sheets can be welded by applying ultrasonic vibration while applying a load to the sheets.

  The position control of the ultrasonic horns 152, 154 and 156 may be performed only by switching the position in the width direction of the sheet when the punching pattern is horizontal with respect to the sheet feeding direction. In the case of corresponding, a swing mechanism (not shown) is provided so that the traveling direction of the ultrasonic horns 152, 154, 156 can be changed to an arbitrary direction, and is moved in the width direction in synchronization with the movement amount of the seat. It is possible to cope with.

  The setting conditions of the ultrasonic horns 152, 154, and 156 may be determined within a range in which the fused portion is not completely 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.

  In the punching press device 118 downstream of the ultrasonic horns 152, 154 and 156, the punched sheet (display optical sheets 10 to 60) is formed by allowing the blade to enter the center portion of the bonded fused portion. It is possible to obtain a composite sheet in which all the pieces or only the end portions of any piece are bonded. Then, the laminated body 202 cut in the same manner as the display optical sheet manufacturing line 70 of FIG. 7 is passed through the cleaning device 92 to remove dust, foreign matter, and the like adhering to the front and back surfaces.

  Next, still another manufacturing method (fifth manufacturing method) of the optical sheet for display will be described. FIG. 11 is a configuration diagram of a display optical sheet manufacturing line 170 applied to the fifth manufacturing method. Note that the optical sheet manufacturing line for display 70 in FIG. 7 (first manufacturing method), the optical sheet manufacturing line 110 for display in FIG. 8 (second manufacturing method), and the display in FIG. 9 (third manufacturing method). The same or similar members as those in the optical sheet production line 130 and the like are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the display optical sheet production line 170, laser heads 172, 174, and 176 are employed instead of the ultrasonic horns 152, 154, and 156 of the display optical sheet production line 150. The laser heads 172, 174, and 176 are arranged on the downstream side of the guide rollers 83, 84, and 85, respectively, similarly to the ultrasonic horns 152, 154, and 156.

  The laser heads 172, 174, and 176 are devices for fusing two or more stacked sheets, similarly to the ultrasonic horns 152, 154, and 156. That is, the laser head 172 fuses the first diffusion sheet 12 and the first prism sheet 14, and the laser head 174 fuses the first prism sheet 14 and the second prism sheet 16. The laser head 176 is for fusing the second prism sheet 16 and the second diffusion sheet 18 together.

  The laser heads 172, 174, and 176 are used only for the joining step, unlike the laser head 90 in the optical sheet manufacturing line 70 for display shown in FIG. 7 (first manufacturing method), and the cutting step is a punching press device 118. Is done. However, the basic specifications and peripheral configuration of the laser heads 172, 174, and 176 are substantially the same as those in the first manufacturing method.

  The setting conditions of the laser heads 172, 174, and 176 may be determined within a range in which the fused portion is not completely melted by heat. If necessary, the bonded portion is cooled by an air cooling mechanism such as air blowing after bonding (fusion). May be.

  In the punching press device 118 downstream of the laser heads 172, 174, 176, the blade (display optical sheets 10 to 60) is punched by allowing the blade to enter the central portion of the bonded fused portion. It is possible to obtain a composite sheet in which all pieces or only end portions of arbitrary pieces are bonded. Then, the laminated body 202 cut in the same manner as the display optical sheet manufacturing line 70 of FIG. 7 is passed through the cleaning device 92 to remove dust, foreign matter, and the like adhering to the front and back surfaces.

  Next, still another manufacturing method (sixth manufacturing method) of the optical sheet for display will be described. FIG. 12 is a configuration diagram of a display optical sheet manufacturing line 190 applied to the sixth manufacturing method. Note that the optical sheet manufacturing line for display 70 in FIG. 7 (first manufacturing method), the optical sheet manufacturing line 110 for display in FIG. 8 (second manufacturing method), and the display in FIG. 9 (third manufacturing method). The same or similar members as those in the optical sheet production line 130 and the like are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the display optical sheet production line 190, one laser head 192 is employed instead of the three laser heads 172, 174, and 176 in the display optical sheet production line 170. The laser head 192 is disposed on the downstream side of the guide roller 85.

  The laser head 192 is a device that fuses two or more stacked sheets. In other words, the laser head 192 fuses the laminated body of the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18.

  The laser head 192 is used only for the joining step, unlike the laser head 90 in the optical sheet manufacturing line 70 for display shown in FIG. 7 (first manufacturing method), and the cutting step is performed by the punching press device 118. However, the basic specifications and peripheral configuration of the laser head 192 are substantially the same as those of the first manufacturing method (see FIG. 7).

  The setting condition of the laser head 192 may be determined within a range in which the fused portion is not completely melted by heat. If necessary, the bonded portion may be cooled by an air cooling mechanism such as air blowing after bonding (fusion). .

  In the punching press device 118 downstream of the laser head 192, all or a part of the punched sheet (display optical sheets 10 to 60) or an arbitrary one is obtained by allowing the cutter to enter the central portion of the bonded fused part. It is possible to obtain a composite sheet in which only the end portions of the two pieces are bonded. Then, the laminated body 202 cut in the same manner as the display optical sheet manufacturing line 70 of FIG. 7 is passed through the cleaning device 92 to remove dust, foreign matter, and the like adhering to the front and back surfaces.

  FIG. 13 shows an example of the cleaning means according to the present invention. Note that a cleaning device 92 made of an adhesive roll is shown in the cleaning means of FIG. The laminated body 200 is conveyed in the Z direction. The laminated body 200 has an adhesive roller (front adhesive roller) 205 on the front side, an adhesive roller (back adhesive roller) 206 on the back side, and adhesive rollers (side adhesive rollers) 207 and 208 on both sides. Is provided. Each of the adhesive rollers 205 to 208 may be a driving roller to which a driving device (not shown) is attached, or may be a free roller to which no driving device is attached. In the present invention, the adhesive rollers provided in the cleaning device 92 are not necessarily limited to the four illustrated. It is sufficient that at least one of the front surface adhesive roller 205, the back surface adhesive roller 206, and the side surface adhesive rollers 207 and 208 is provided. Further, a plurality of front surface adhesive rollers, back surface adhesive rollers, and side surface adhesive rollers may be provided.

  Also, the cleaning devices 73, 75, 77, 79 shown in FIGS. 7 to 12 are preferably in the same form as the cleaning device 92. In this case, what is cleaned is the diffusion sheets 12 and 18 and the prism sheets 14 and 16. The form of each of the adhesive rollers 205 to 208 is not particularly limited, but a cleaning roller for an optical member is preferably used. Further, the material of each of the adhesive rollers 205 to 208 is not particularly limited, but silicon rubber, butyl rubber, and the like are preferably used.

  FIG. 14 shows another embodiment of the cleaning means according to the present invention. The cleaning device 210 shown in FIG. 14 includes an adhesive film roll 211. An adhesive film 212 is supplied from the adhesive film roll 211. The pressure-sensitive adhesive film 212 is brought into contact with the surface of the laminate 200 by the pressing roller 213 and removes dust, foreign matter, and the like on the surface. Then, the adhesive film 212 is wound around the winding roll 214. The cleaning device 210 is not limited to the one provided on the front surface side of the laminated body 200, and may be provided on the back surface side and the both side surfaces side. Further, the cleaning devices 73, 75, 77, and 79 shown in FIGS. 7 to 12 may have the same form as the cleaning device 210 of FIG. 14, as in the case described with reference to FIG. .

  In the present invention, the cleaning means is not limited to that shown in FIGS. For example, a vacuum device, a static eliminator, or the like can be used.

  Next, a planar arrangement of sheets (display optical sheets 10 to 60) punched out from a laminate of the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18 will be described.

  FIG. 15 is a diagram for explaining a planar arrangement of sheets (display optical sheets 10 to 60) punched from the laminate 200 in the first manufacturing method, and FIG. 16 is a second to sixth manufacturing method. FIG. 3 is a diagram for explaining a planar arrangement of sheets (optical sheets for display 10 to 60) punched from a laminated body 202.

  15A shows a state in which fusion (joining process) and punching (cutting process) parallel to the transport direction Z of the laminate 200 are performed, and FIG. 15B shows the transport direction of the laminate 200. A state in which fusion (bonding process) and punching (cutting process) are performed obliquely with respect to Z is shown. In the figure, the point on the peripheral edge of the sheet punched out from the laminate 200 indicates the fused position.

  16A shows a state in which fusion or adhesion (bonding process) is performed in an oblique direction with respect to the transport direction Z of the laminate 202, and FIG. The state which performs melt | fusion or adhesion | attachment (joining process) in the diagonal direction is shown. In the figure, the point on the peripheral edge of the sheet punched out from the laminate indicates a fusion point or an adhesion point.

  As described above, according to the present invention, an optical sheet for display can be manufactured at a low cost and with high quality by a simpler process than before.

  Moreover, according to this invention, the following effects are also acquired.

1) Improvement of Product Value by Cost Reduction and Thinning Optical sheets used for large liquid crystal televisions need rigidity, and therefore, the thickness of the support is about twice that of the conventional one. However, since the optical sheet according to the present invention is a composite of the sheets, it can have sufficient rigidity without increasing the thickness of each sheet, and the thickness of each layer can be reduced.

2) Improved performance by preventing reduction of light collection effect Some products have a matte backside to prevent scratches on the lens sheet (to make the scratches less noticeable). The optical sheet according to the present invention is not necessary, and not only the production cost can be reduced, but also the light collection effect can be prevented from being reduced by the mat treatment, and the performance is improved.

  As mentioned above, although each example of embodiment of the manufacturing method of the optical sheet for a display which concerns on this invention was demonstrated, this invention is not limited to the example of the said embodiment, Various aspects can be taken.

  For example, in the example of the present embodiment, the prisms of the first prism sheet 14 and the second prism sheet 16 are facing upward in any case, but the prisms can be stacked with the prisms facing downward. Moreover, the layer structure of the optical sheet for display is not limited to the example of embodiment, For example, a protective sheet can also be laminated | stacked on an up-and-down surface. Even if it is the above structures, it acts similarly to this embodiment and the same effect is acquired.

   Hereinafter, the present invention will be described in more detail with reference to Experiments 1 to 3 according to the present invention and Experiment 4 which is a comparative experiment. The description will be made in detail in Experiment 1, and only the experimental conditions different from Experiment 1 are described in the other Experiments 2 to 4. In addition, materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Experiment 1]
[Production of prism sheet]
Base films used for the first prism sheet 14 and the second prism sheet 16 were produced. This base film is used in common for the first prism sheet 14 and the second prism sheet 16.

-Preparation of resin liquid The compounds shown in the table of Fig. 17 were mixed at the stated mass ratio, heated to 50 ° C and dissolved by stirring to obtain a resin liquid. In addition, the name and content of each compound are as follows.

EB3700: Everkrill 3700, manufactured by Daicel UC Corporation,
Bisphenol A type epoxy acrylate,
(Viscosity: 2200 mPa · s / 65 ° C)
BPE200: NK ester BPE-200, manufactured by Shin-Nakamura Chemical Co., Ltd.
Ethylene oxide-added bisphenol A methacrylate,
(Viscosity: 590 mPa · s / 25 ° C)
BR-31: New Frontier BR-31, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Tribromophenoxyethyl acrylate,
(Solid at normal temperature, melting point 50 ° C or higher)
LR8883X: Lucirin LR8883X, a north radical generator manufactured by BASF Corporation,
FIG. 18 shows a schematic diagram of an ethyl-2,4,6-trimethylbenzoylethoxyphenyl osphine oxide MEK: methyl ethyl ketone prism sheet manufacturing apparatus (hereinafter referred to as manufacturing apparatus) 220. The manufacturing apparatus 220 includes a film supply device 224 that supplies the base film 222, a coating device 226 that applies a radioactive curable resin liquid (hereinafter referred to as a resin liquid) onto the base film 222, and an uneven roller (also referred to as a mold roll). Embossing roller 228, nip roller 230, peeling roller 232, resin curing device 234, and winder 236. With these configurations, the prism sheet 238 is obtained from the base film 222. Moreover, it is preferable that the protective film supply apparatus 242 which sends out the protective film 240 which protects the prism sheet 238 is also provided.

  The film supply device 224 feeds the base film 222, and includes a feed roll around which the base film 222 is wound. The coating device 226 is a device that applies a resin liquid to the surface of the base film 222, and a resin liquid tank 250 that supplies the resin liquid, a liquid feed pump 252 that supplies the resin liquid, a coating head 254, and a coating liquid. The support roller 256 is configured to wind and support the base film 222 and various pipes. As the coating head 254, a die coater (extrusion type coater) was used. Further, a drying device 258 for drying the resin liquid is provided on the downstream side of the coating device 226.

  Then, the prism sheet 238 was manufactured using the prism sheet manufacturing apparatus 220. As the sheet W, transparent PET (polyethylene terephthalate) having a width of 500 mm and a thickness of 100 μm was used as the base film 222. As the embossing roller 228, a roller made of S45C having a length (width direction of the sheet W) of 700 mm and a diameter of 300 mm and having a nickel surface material was used. Grooves with a pitch of 50 μm in the roller axial direction were formed on the entire circumference of the surface of the roller by cutting using a diamond tool (single point). The cross-sectional shape of the groove is a triangular shape with an apex angle of 90 degrees, and the bottom of the groove is a triangular shape with a 90 degree without a flat portion. That is, the groove width is 50 μm and the groove depth is about 25 μm. Since the groove is endless with no seam in the circumferential direction of the roller, the embossing roller 228 can form a lenticular lens (prism sheet) having a triangular cross section on the sheet W. The surface of the roller was plated with nickel after the grooves were processed.

  As the coating device 226, a die coater using an extrusion type coating head 254 was used. As the coating solution F (resin solution), a solution having the composition described in the table of FIG. 15 was used and placed in the resin solution tank 250. The supply amount of each coating liquid F to the coating head 254 was controlled by the liquid feed pump 252 so that the wet thickness of the coating liquid F (resin) was 20 μm after drying the organic solvent. A hot air circulation type drying device 258 was used as a drying means. The temperature of the hot air was 100 ° C.

As the nip roller 230, a roller having a diameter of 200 mm and a silicon rubber layer having a rubber hardness of 90 formed on the surface thereof was used. The nip pressure (effective nip pressure) for pressing the sheet W by the embossing roller 228 and the nip roller 230 was 0.5 Pa. A metal halide lamp was used as the resin curing device 234, and irradiation was performed with an energy of 1000 mJ / cm ² . As described above, a prism sheet having a concavo-convex pattern was obtained.

[Production of First Diffusion Sheet 12]
A first diffusion sheet (under diffusion sheet) 12 was produced by forming each layer in the order of the undercoat layer, the backcoat layer, and the light diffusion layer by the following method.

・ Undercoat layer A liquid A as an undercoat layer coating solution having the following composition was applied on one side of a polyethylene terephthalate film (support) having a thickness of 100 μm with a wire bar (wire size: # 10), and 2 at 120 ° C. The film was dried for 5 minutes to obtain an undercoat layer having a film thickness of 1.5 μm.

(Coating solution for undercoat layer)
Methanol 4165g
Julimer SP-50T (Nippon Pure Chemicals) 1495g
339 g of cyclohexanone
Julimer MB-1X (Nippon Pure Chemicals Co., Ltd.) 1.85g
(Organic particles: polymethylmethacrylate cross-linked type, spherical ultrafine particles with a weight average particle size of 6.2 μm)
-Back coat layer On the opposite side of the support on which the undercoat layer was applied, the B liquid as the back coat layer coating liquid having the following composition was applied with a wire bar (wire size: # 10), and 120 ° The film was dried at C for 2 minutes to obtain a backcoat layer having a thickness of 2.0 μm.

(Coating solution for back coat layer)
4171g of methanol
Julimer SP-65T (Nippon Pure Chemicals) 1487g
340 g of cyclohexanone
Julimer MB-1X (Nippon Pure Chemicals Co., Ltd.) 2.68g
(Organic particles: polymethylmethacrylate cross-linked type, spherical ultrafine particles with a weight average particle size of 6.2 μm)
-Light diffusion layer C liquid as a light diffusion layer coating solution having the following composition is applied to the undercoat layer side of the support prepared above with a wire bar (wire size: # 22), and at 120 ° C for 2 minutes. It was made to dry and the light-diffusion layer was obtained. In addition, although mentioned later, this light-diffusion layer obtained what apply | coated immediately after preparing C liquid, and what apply | coated after adjusting C liquid and leaving still for 2 hours, respectively.

(Coating liquid for light diffusion layer)
Cyclohexanone 20.84g
Disparon PFA-230 Solid content 20% by mass 0.74g
(Particle sedimentation inhibitor: fatty acid amide, manufactured by Enomoto Kasei Co., Ltd.)
Acrylic resin (Dianar BR-117, manufactured by Mitsubishi Rayon Co., Ltd.) 20% by mass methyl ethyl ketone solution 17.85 g
Julimer MB-20X (Nippon Pure Chemicals) 11.29g
(Organic particles: polymethylmethacrylate cross-linked type, spherical ultrafine particles with a weight average particle diameter of 18 μm)
F780F (Dainippon Ink Co., Ltd.) 0.03g
(Methyl ethyl ketone 30% by mass solution)
[Creation of Second Diffusion Sheet 18]
The same conditions and the same flow as the first diffusion sheet 12 except that the addition amount of the Jurimer MB-20X in the light diffusion layer of the first diffusion sheet 12 is changed from 11.29 g to 1.13 g. A second diffusion sheet (upper diffusion sheet) 18 was produced.

[Preparation of Optical Sheet 10 for Display: Example]
A display using the above-described sheets, in which the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18 are laminated in order from the bottom as shown in FIG. An optical sheet (optical sheet module) 10 was prepared.

  As the manufacturing apparatus, the display optical sheet manufacturing line 70 (first manufacturing method) shown in FIG. 7 described above was used. As the laser beam irradiation apparatus including the laser head 90, a carbon dioxide laser irradiation apparatus was used. The wavelength is 10 μm, the output is 25 W, and the frequency is 50 kHz.

  The cleaning device 92 shown in FIG. 13 was used. Further, the cleaning devices 73, 75, 77, and 79 are the same as the cleaning device 92. A butyl-based cleaner (Audio Technica Corp .; HC-530) was used for the adhesive rollers 205-208.

  The optical sheet for display 10 was produced by a method in which four sides of the four circumferences were joined simultaneously by cutting out the four circumferences of the laminated body by laser light irradiation. And 100 sets of the optical sheets 10 for a display were evaluated, respectively, and the presence or absence of the flaw failure which arose at the time of handling was evaluated. In the evaluation, the bright line due to the scratch was visually observed, and the bright line was judged as a defective product. In Experiment 1, 99 sets of good products were obtained.

[Experiment 2 to Experiment 4]
In Experiment 2, the experiment was performed under the same conditions as Experiment 1 except that the cleaning devices 73, 75, 77, and 79 were removed. 97 sets of non-defective products were obtained. In Experiment 3, the experiment was performed under the same conditions as Experiment 1 except that the cleaning device 92 was removed. 92 sets of good products were obtained. In Experiment 4, the cleaning devices 73, 75, 77, 79 and the cleaning device 92 were removed. That is, no cleaning device was provided in the display optical sheet production line 70. Otherwise, the experiment was performed under the same conditions as in Experiment 1. As a result, only 65 sets of good products were obtained.

  From the above results, according to the examples of the present invention (Experiment 1 to Experiment 3), it was possible to realize the reduction of dust defects at the time of punching the laminated body and to confirm the improvement of the yield.

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 Configuration diagram of optical sheet production line for display applied to second production method Configuration diagram of optical sheet manufacturing line for display applied to third manufacturing method Configuration diagram of optical sheet manufacturing line for display applied to fourth manufacturing method Configuration diagram of optical sheet manufacturing line for display applied to fifth manufacturing method Configuration diagram of optical sheet manufacturing line for display applied to sixth manufacturing method It is the schematic of the cleaning apparatus used for the manufacturing method of the optical sheet for displays of this invention. It is the schematic of other embodiment of the cleaning apparatus used for the manufacturing method of the optical sheet for displays of this invention. The figure explaining the plane arrangement | positioning of the sheet | seat punched out from a laminated body in a 1st manufacturing method. The figure explaining the planar arrangement | positioning of the sheet | seat punched from a laminated body in the 2nd-6th manufacturing method. Table showing the composition of the resin liquid used to create the prism sheet Configuration diagram of prism sheet manufacturing equipment

Explanation of symbols

  10, 20, 30, 40 ... Optical sheet for display, 12 ... First diffusion sheet, 14 ... First prism sheet, 16 ... Second prism sheet, 18 ... Second diffusion sheet, 73, 75, 77, 79, 92 ... Cleaning device, 200, 202 ... Laminate

Claims (11)

Joining to form a laminate by supplying at least one prism sheet in which convex lenses formed in a uniaxial direction are adjacent to each other and arranged on substantially the entire surface and at least one diffusion sheet for irregularly reflecting light. In the method for producing an optical sheet for display, comprising: a step; and a cutting step of cutting the optical sheet for display from the laminate.
A method for producing an optical sheet for display, comprising: a first cleaning step of cleaning at least one of the prism sheet, the diffusion sheet, or the laminated body before the cutting step. Joining to form a laminate by supplying at least one prism sheet in which convex lenses formed in a uniaxial direction are adjacent to each other and arranged on substantially the entire surface and at least one diffusion sheet for irregularly reflecting light. In the method for producing an optical sheet for display, comprising: a step; and a cutting step of cutting the optical sheet for display from the laminate.
A method for producing an optical sheet for display, comprising a second cleaning process for cleaning the optical sheet for display after the cutting process.   3. The method for manufacturing an optical sheet for display according to claim 2, further comprising a first cleaning step of cleaning at least one of the prism sheet, the diffusion sheet, and the laminated body before the cutting step.   4. The method for producing an optical sheet for display according to claim 1, wherein the laminated body has one diffusion sheet formed on one surface side of at least one prism sheet. 5. .   5. The method of manufacturing an optical sheet for display according to claim 4, wherein another diffusion sheet is formed on the opposite side of the one surface of the at least one prism sheet.   The cleaning device provided in the first cleaning step or the second cleaning step is used to clean at least one of the prism sheet, the diffusion sheet, or the laminated body. The manufacturing method of the optical sheet for a display of claim | item.   The display device according to claim 6, wherein the cleaning unit is provided on at least one front surface, back surface, or both side surfaces of the prism sheet, the diffusion sheet, or the laminate, and cleans at least one surface. Manufacturing method of optical sheet.   The method for producing an optical sheet for display according to claim 6 or 7, wherein the cleaning means is an adhesive roller.   The optical sheet for display according to any one of claims 1 to 8, wherein the joining step is a step of joining the lens sheet and the diffusion sheet at at least one of the peripheral edges thereof. Production method.   A display optical sheet manufactured by the method for manufacturing a display optical sheet according to any one of claims 1 to 9.   An image display device using the optical sheet for display according to claim 10.

Images