JP2007078884A - Manufacturing method of display optical sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of display optical sheet, which punches high-quality display optical sheet by suppressing the occurrence of cutting dusts and cracks, and reduces defects due to damages and foreign matter sticking when punching stacked sheets. <P>SOLUTION: The manufacturing method of display optical sheet comprises: a stacking process of preparing a stacked body by respectively stacking at least one diffusion sheet and lens sheet of which the flat plane size is a product size or more; a punching process of making a punched body by punching the stacked body into the product size; and a joining process of joining the diffusion sheet and the lens sheet on at least one part corresponding to the peripheries of the punched body. A punching blade of a punching die used in the punching process is characterized in that the edge angle of a blade is 30 to 60°, the thickness of the blade is 0.7 to 0.9 mm, and the edge hardness of the blade is 45 to 80 Hs in shore hardness. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical sheet for display, and more particularly, to a method for manufacturing an optical sheet for display that is easy to assemble and handle a display member, and that is inexpensive and has high performance.

  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, 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.

  In addition, when punching the overlapped light diffusion sheet and flat plate lens (prism sheet), there is a problem that the cut surface is rough and a large number of chips are generated.

  The present invention has been made in view of such circumstances, and suppresses generation of cutting waste and cracks when punching laminated sheets, reduces defects due to scratches and foreign matter adhesion, and provides a high-quality display. It aims at providing the manufacturing method of the optical sheet for a display which can punch the optical sheet for a display.

  In order to achieve the above object, the invention according to claim 1 includes a laminating step of laminating at least one diffusion sheet and a lens sheet each having a planar size equal to or larger than a product size, and forming the laminate. Manufacturing an optical sheet for display, comprising: a punching process for punching a body into a product size to create a punched body; and a bonding process for bonding the diffusion sheet and the lens sheet at at least one location corresponding to the periphery of the punched body A punching die punching blade used in the punching step has a cutting edge angle of 30 ° to 60 °, a blade thickness of 0.7 mm to 0.9 mm, and a cutting edge hardness of 45 Hs to 80 Hs in Shore hardness. A method for producing an optical sheet for display is provided.

  Thereby, it is possible to punch the overlapped diffusion sheet and lens sheet into a predetermined shape without generating chips on the cut surface.

  As described above, according to the present invention, generation of chips on the cut surface can be suppressed, and the overlapped diffusion sheet and lens sheet can be punched into a predetermined shape.

  Hereinafter, a method for producing an optical sheet for display according to the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, a light diffusion sheet (diffusion sheet) and a prism sheet (lens sheet) manufactured separately are integrated by adhering at least one point, and an optical sheet for display is manufactured by punching into a desired shape with a punching die. In this method, a method of punching and manufacturing a composite optical sheet with high quality and accuracy is provided.

  First, a configuration of an example of an optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to the present invention will be described, and then a method for manufacturing the optical sheet for display will be described.

  The optical sheet (optical film) is a general term for various sheets having optical functions, and is a diffusion sheet, a polarizing plate (diffusion sheet film), various lens sheets (lenticular lenses, fly-eye lenses (amber eye lenses). ), A prism sheet, etc.) are typical, but a protective sheet (protective film) or the like that hardly performs an optical function is also included.

  FIG. 1 is a cross-sectional view showing a configuration of an example of an optical sheet for display manufactured by the method for manufacturing an optical sheet for display 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 configuration of the diffusion sheet and the prism sheet of the optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to the present embodiment is as described above: first diffusion sheet + first prism sheet + second The configuration is not limited to the prism sheet + second diffusion sheet, and the following configuration may be used.

  For example, a configuration of diffusion sheet + prism sheet, or a configuration of diffusion sheet + first prism sheet + second prism sheet, or a configuration of first diffusion sheet + prism sheet + second diffusion sheet, or prism sheet + A configuration of a diffusion sheet or a configuration of a first prism sheet + second prism sheet + diffusion sheet is conceivable, and any of these configurations may be used.

  When the first prism sheet and the second prism sheet are stacked, the second prism sheet has a ridge line direction of the second prism sheet and a ridge line direction of the first prism sheet substantially perpendicular to each other. It shall be pasted together. The ridge line direction is preferably substantially perpendicular, but the angle may be adjusted to prevent moiré or the like.

  In FIG. 1, a first diffusion sheet 12 and a 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 a predetermined light diffusion performance. It is. 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 fill, 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 and the second prism sheet 16 are lens sheets in which convex lenses formed in one axial direction are adjacently arranged on substantially the entire surface. For example, the pitch is 50 μm and the height of the unevenness. 25 μm, and 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 so that the axes of the convex lenses (prisms) are substantially orthogonal to each other. That is, in FIG. 1, 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. 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.

  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 and the 2nd prism sheet 16 is not necessarily limited to said example, If a desired uneven | corrugated shape can be formed on the surface, another manufacturing method can also be employ | adopted. .

  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 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.

  In addition, as an example of the optical sheet for a display manufactured with the manufacturing method of the optical sheet for a display which concerns on this invention, it is not limited to this, There can be various other examples.

  For example, when a wide diffusion performance like the optical sheet for display 10 as described above is not required, the second diffusion sheet is omitted from the optical sheet for display 10 described above shown in FIG. It may be an example. Further, when the diffusion performance in the direction perpendicular to the paper surface as in the display optical sheet 10 described above is not required, the second prism sheet 16 may be omitted.

  Further, when the wide diffusion performance and the diffusion performance in the direction perpendicular to the paper surface are not required as in the above-described optical sheet for display 10, both the second diffusion sheet and the second prism sheet may be omitted. it can.

  Moreover, when the wide diffusion performance like the above-described optical sheet for display 10 is not required, the first diffusion sheet may be omitted. Further, when the wide diffusion performance and the diffusion performance in the direction perpendicular to the paper surface are not required as in the display optical sheet 10 described above, both the first diffusion sheet and the second prism sheet are omitted. May be.

  Next, the manufacturing method of the optical sheet for a display is demonstrated.

  FIG. 2 is a configuration diagram of a display optical sheet production line 21 applied to the method for producing a display optical sheet according to the present invention.

  In FIG. 2, rolls 12B, 14B, 16B, 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 shown in FIG. The prism sheet 16 and the second diffusion sheet 18 are wound around the roll.

  The rolls 12B, 14B, 16B and 18B are respectively supported by the rotation shafts of unillustrated feeding means, and the first diffusion sheet 12, first prism sheet 14, The two prism sheets 16 and the second diffusion sheet 18 can be fed out at substantially the same speed.

  The fed first diffusion sheet 12, first prism sheet 14, second prism sheet 16, and second diffusion sheet 18 are supported by guide rollers G, G,.

    Further, as shown in FIG. 2, dispensers 42, 44 and 46 and a punching press device 48 are arranged. The dispensers 42, 44, and 46 are supply devices that discharge adhesive from the tip. The dispenser 42 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 44 includes the first prism. In order to bond the sheet 14 and the second prism sheet 16, an adhesive is supplied to the surface of the first prism sheet 14, and the dispenser 46 includes the second prism sheet 16 and the second diffusion sheet. In order to bond 18, an adhesive is supplied to the surface of the second prism sheet 16.

  The adhesive supplied from the dispensers 42, 44 and 46 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.

  Moreover, it is preferable to provide a drying means for drying the adhesive between the downstream press roller (guide roller G). 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 42, 44, and 46 are attached to an X drive robot shaft or an XY drive robot shaft that can move in the X direction (sheet width direction) or XY direction, and can perform positioning to an arbitrary position and arbitrary trajectory movement. It has become.

An adhesive is supplied from these dispensers 42, 44, and 46 to the joining portion at the periphery of the laminate, and the periphery of the laminate is joined by a downstream press roller (guide roller G) while the laminate is conveyed.
A punching press device 48 downstream of the dispensers 42, 44 and 46 is a device for cutting the peripheral edge of the laminate into a product size. In this punching press device 48, the edge of the punched sheet (optical sheet for display 10) or only an end part of the punched sheet is bonded by allowing the cutter to enter the center of the bonded part. A composite sheet can be obtained.

  In the manufacturing method of the optical sheet for display described above, the laminated body is joined by supplying the adhesive using the dispensers 42, 44, and 46, but the joining method of the laminated body is not limited to this, and various It is possible to use a method.

  For example, although not shown, a tape supply device may be used in place of the dispensers 42, 44 and 46, and a double-sided tape may be supplied to join the laminate.

  Alternatively, an ultrasonic horn may be used in place of the dispensers 42, 44 and 46, and the laminated sheets may be fused. Further, instead of the ultrasonic horn, a laser head may be used to fuse the stacked sheets. In addition, this laser head may be one that fuses two sheets each of which is laminated, or may fuse four sheets shown in FIG. 2 together.

  Next, regarding the planar arrangement of the sheet (optical sheet for display 10) punched out from the laminate of the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18. explain.

  FIG. 3 is a diagram for explaining a planar arrangement of a sheet (display optical sheet 10) punched from a laminate in the manufacturing method of the present embodiment.

  In FIG. 3, (A) shows a state in which fusion or adhesion (joining process) is performed in a direction parallel to and orthogonal to the transport direction of the laminate, and (B) shows the transport direction of the laminate. A state in which fusion or adhesion (joining process) is performed in parallel and orthogonal directions 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.

(Example)
Next, more specific examples will be described.

  Here, as a processing target, a first diffusion sheet 12 having a thickness of 1.1 mm from a lower layer, a first prism sheet 14 having a thickness of 1.5 mm, a second prism sheet 16 having a thickness of 1.5 mm, and a thickness. A composite sheet (optical sheet 10 for display) in which the second diffusion sheet 18 of 1.1 mm was bonded by laser welding was used.

  This composite sheet was punched with a punching press 48 as shown in FIG. FIG. 4 shows the punching press device 48 in an enlarged manner. As shown in FIG. 4, the punching press device 48 punches a composite sheet 54 (display optical sheet 10) conveyed between the punching die 50 and the face plate 52 by a punching blade 56 provided in the punching die 50. To be processed.

  FIG. 5 shows the punching blade 56 in an enlarged manner. The punching blade 56 has a blade thickness d and a blade edge angle θ, and as shown in FIG. Punching was performed using a test die having a test blade 56 having the dimensions shown in FIG.

  As for the result of punching, the cut surface was photographed with a confocal microscope (Lasertec, HD100), and the state of the cut surface was evaluated.

  The evaluation is based on the presence or absence of cutting waste from the cut surface by visual inspection, and as shown in FIG. The result of obtaining a cut surface was marked with a cross.

  For comparison, FIG. 7 shows an example of a good cut surface where no cutting waste is generated, and FIG. 8 shows an example of a defective cutting surface where cutting waste is generated.

  As shown in FIG. 7, a good cut surface has a uniform cut surface and no generation of waste. On the other hand, as shown in FIG. 8, a defective cut surface has a rough cut surface and a large amount of waste.

  From this result, it is understood that the punching die preferably has a cutting edge angle θ of 30 ° to 60 °, a blade thickness d of 0.7 mm to 0.9 mm, and a cutting edge hardness of 45 Hs to 80 Hs. Therefore, by performing punching using a punching die having such dimensions, it is possible to punch the overlapped diffusion sheet and prism sheet into a predetermined shape without generating chips on the cut surface. As a result, a protective sheet on the surface becomes unnecessary, and the material cost can be reduced.

  Further, the number of work for assembling the members necessary for assembling the backlight is reduced, and labor costs can be reduced. In addition, it is possible to prevent dust from adhering due to peeling electrification that occurs when the protective sheet is peeled off, and the quality of the product can be improved.

  In addition, by punching after bonding the prism sheet and the diffusion sheet, the time required for punching is less than half compared with the case of punching each sheet individually, and productivity can be improved. .

  Next, a specific method for manufacturing the diffusion sheet and the prism sheet used in this example will be described.

  Prism sheets used for the first prism sheet 14 and the second prism sheet 16 used in the above examples were prepared. This prism sheet is used in common for the first prism sheet 14 and the second prism sheet 16.

  First, regarding the adjustment of the resin liquid, the compounds shown in the table of FIG. 9 were mixed at the stated weight ratio, heated to 50 ° C., dissolved by stirring, and a resin liquid was obtained. 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,
Ethyl-2,4,6-trimethylbenzoylethoxyphenyl osphine oxide MEK: methyl ethyl ketone Next, the prism sheet was manufactured using the prism sheet manufacturing apparatus having the configuration shown in FIG.

  As the sheet W, a transparent PET (polyethylene terephthalate) film having a width of 500 mm and a thickness of 100 μm was used.

  As the embossing roller 83, 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 surface material of nickel 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 this groove is endless with no seam in the circumferential direction of the roller, the embossing roller 83 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 means 82, a die coater using an extrusion type coating head 82C was used.

  As the coating solution F (resin solution), a solution having the composition described in the table of FIG. 9 was used. The supply amount of each coating liquid F to the coating head 82C was controlled by the supply device 82B so that the wet thickness of the coating liquid F (resin) was 20 μm after drying the organic solvent.

  As the drying means 89, a hot air circulation type drying apparatus was used. The temperature of the hot air was 100 ° C.

  As the nip roller 84, 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 83 and the nip roller 84 was 0.5 Pa.

A metal halide lamp was used as the resin curing means 85, 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.

  Next, the manufacturing method of a diffusion sheet is demonstrated.

  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.

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

  The composition of the undercoat layer coating solution is as follows.

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)
Moreover, as a backcoat layer, the liquid B as a coating liquid for backcoat layers having the following composition was applied to the opposite surface of the support on which the undercoat layer was applied with a wire bar (wire size: # 10). And dried at 120 ° C. for 2 minutes to obtain a backcoat layer having a thickness of 2.0 μm.

  The composition of the backcoat layer coating solution is as follows.

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)
Next, as the light diffusion layer, the liquid C as a light diffusion layer coating solution having the following composition was applied to the undercoat layer side of the support prepared above with a light bar (wire size: # 22), and 120 ° The mixture was dried at C for 2 minutes to obtain a light diffusion layer. 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.

  The composition of the light diffusion layer coating solution is as follows.

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)
Next, a manufacturing method of the second diffusion sheet 18 is that except that the addition amount of the Jurimer MB-20X of the light diffusion layer of the first diffusion sheet 12 is changed from 11.29 g to 1.13 g. Then, a second diffusion sheet (upper diffusion sheet) 18 was produced under the same conditions and the same flow as the first diffusion sheet 12 described above.

  Next, using each of the above-mentioned sheets, the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion are sequentially shown from the bottom as shown in FIG. The optical sheet 10 for display (module of an optical sheet) formed by laminating the sheets 18 was produced.

  As the manufacturing apparatus, in the optical sheet manufacturing line 21 for display shown in FIG. 2, a dispenser 42, 44, 46 is not provided, and a laser beam irradiation apparatus including a laser head is arranged instead of the punching press apparatus 48. What was made to perform welding (joining process) substantially simultaneously with the cutting (cutting process) by irradiation was used.

  A carbon dioxide laser irradiation device was used as the laser beam irradiation device including the laser head. The wavelength is 10 μm, the output is 25 W, and the frequency is 50 kHz.

  The optical sheet 10 for display was made 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.

  As mentioned above, although the manufacturing method of the optical sheet for a display of this invention was demonstrated in detail, this invention is not limited to the above example, In the range which does not deviate from the summary of this invention, various improvement and deformation | transformation are performed. Of course it is also good.

It is sectional drawing of embodiment of the optical sheet for displays manufactured by the manufacturing method of the optical sheet for displays which concerns on this invention. It is a block diagram of the optical sheet manufacturing line for displays applied to the manufacturing method of the optical sheet for displays in this embodiment. (A), (B) is a figure explaining the planar arrangement | positioning of the sheet | seat punched out from a laminated body in the manufacturing method of the optical sheet for a display in this embodiment. It is an enlarged view of the punching press apparatus in the optical sheet manufacturing line for display of FIG. It is an enlarged view of the punching blade of the punching press apparatus of FIG. It is explanatory drawing which shows the dimension example of the punching blade used by the test in a present Example, and evaluation of the punching result. It is a figure which shows the favorable cut surface in the result of a present Example. It is a figure which shows the defective cut surface in the result of a present Example. It is a table | surface which shows the composition of the resin liquid used for preparation of a prism sheet. It is a block diagram of the manufacturing apparatus of a prism sheet.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Display optical sheet, 12 ... 1st diffusion sheet, 14 ... 1st prism sheet, 16 ... 2nd prism sheet, 18 ... 2nd diffusion sheet, 21 ... Optical sheet production line for display, 42, 44, 46 ... dispenser, 48 ... punching press device, 50 ... punching die, 52 ... face plate, 54 ... composite sheet, 56 ... punching blade

Claims (1)

A laminating step of laminating at least one diffusion sheet and a lens sheet each having a planar size equal to or larger than the product size to create a laminate; a punching step of punching the laminate into a product size to create a punched body; and A method for producing an optical sheet for a display, comprising a joining step of joining the diffusion sheet and the lens sheet at at least one location corresponding to the periphery of the punched body,
The punching die used in the punching process has a cutting edge angle of 30 ° to 60 °, a blade thickness of 0.7 mm to 0.9 mm, and a cutting edge hardness of 45Hs to 80Hs in Shore hardness. A method for producing an optical sheet for display.

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