KR20070030122A - Optical sheet for display - Google Patents

Abstract

An optical sheet for a display is provided to improve the strength and quality of optical sheets and to prevent problems caused due to thermal expansion/contraction of plural films. In an optical sheet(10) for a display, lens sheets(14,16) are composed of a lens layer formed on the entire surface by disposing convex lenses formed in a first axial direction, adjacently to each other and a first support layer for supporting the lens layer. Diffusion sheets(12,18) having a diffusion layer and a second support layer for supporting the diffusion layer are laminated on the surface and/or the back side of one lens sheet. The lens sheet and the diffusion sheet are bonded on at least one spot of the peripheral edge.

Description

Optical sheet for display {OPTICAL SHEET FOR DISPLAY}

1 is a cross-sectional view of an embodiment of an optical sheet for display manufactured by the method for manufacturing an optical sheet for display according to the present invention.

2 is a cross-sectional view of another embodiment of an optical sheet for display.

3 is a cross-sectional view of still another embodiment of an optical sheet for display.

4 is a cross-sectional view of still another embodiment of an optical sheet for display.

5 is a cross-sectional view of still another embodiment of an optical sheet for display.

6 is a cross-sectional view of still another embodiment of an optical sheet for display.

7 is a configuration diagram of an optical sheet manufacturing line for display applied to the first manufacturing method.

8 is a configuration diagram of an optical sheet manufacturing line for display applied to a second manufacturing method.

9 is a configuration diagram of an optical sheet manufacturing line for display applied to a third manufacturing method.

10 is a configuration diagram of an optical sheet manufacturing line for display applied to a fourth manufacturing method.

11 is a configuration diagram of an optical sheet manufacturing line for display applied to a fifth manufacturing method.

12 is a configuration diagram of an optical sheet manufacturing line for display applied to a sixth manufacturing method.

It is a figure explaining the planar arrangement of the sheet punched from a laminated body in a 1st manufacturing method.

It is a figure explaining the planar arrangement of the sheet punched from a laminated body in the 2nd-6th manufacturing methods.

FIG. 15 is a table showing the composition of a resin liquid used for producing a prism sheet. FIG.

16 is a configuration diagram of an apparatus for manufacturing a prism sheet.

17 is a table which shows the composition of the resin liquid used for preparation of the prism sheet in the second comparative example.

<Description of the symbols for the main parts of the drawings>

10, 20, 30, 40 ... · optical sheet for display

12 ... first diffusion sheet

14 ... first prism sheet

16 second prism sheet

18 ... second diffusion sheet

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sheet for display, and more particularly, to an optical sheet for display configured by stacking a lens sheet and a diffusion sheet.

Background Art In recent years, films for diffusing light from light sources such as light guide plates, lens films for condensing light in the front direction, and the like have been used for use in electronic displays such as liquid crystal display devices and organic EL.

In this case, there are many examples in which various optical films (sheets) are laminated and used. For example, in Patent Document 1, a semi-reflective polarizing film formed by laminating a reflective polarizing film, a retardation film, and a semi-transmissive semi-reflective layer in an arbitrary order, and further comprising an absorbing polarizing film on the outside of these three layers. Is being provided. The film of five layers is interposed between the light source device and the liquid crystal cell, and it is said that the screen brightness is increased or power consumption is suppressed by this configuration.

Moreover, in patent documents 2-4, the film which integrated the function of one light-diffusion film and a lens film is disclosed.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-184575

[Patent Document 2] Japanese Patent Application Laid-Open No. 7-230001

[Patent Document 3] Japanese Patent No. 3123006

[Patent Document 4] Japanese Patent Application Laid-Open No. 5-341132

However, in the above-described conventional structure, in order to laminate a plurality of layers of films, it is required to go through a plurality of processes, which makes the process complicated and increases the cost.

In addition, flat lenses such as lenticular lenses and prism sheets are easily damaged and dirty, and are generally delivered in a state where a protective sheet is attached to the surface.

However, such a protective sheet is only discarded after being peeled from the flat lens, is not only useful as a resource, but also a factor of cost increase, which is not preferable. Moreover, the operation | work which peels a protective sheet from a flat plate lens is necessary, and may reduce productivity by that much. Moreover, when peeling a protective sheet from a flat plate lens, it is easy to adhere | attach a contamination, such as dust, to a flat plate lens by peeling charge, and there are many problems also in quality.

In addition, when laminating a plurality of layers of films (sheets), damage to the film is likely to occur due to friction during lamination, friction due to thermal expansion and thermal contraction, friction due to handling, and the like.

In addition, in order to correct a defect (deformation or curling, etc.) due to mismatching due to thermal expansion and thermal contraction between a plurality of films, measures such as increasing the thickness of individual films (improving rigidity, etc.) may be necessary. There are also many disadvantages such as restrictions and cost increases.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the display optical sheet which improved the handleability at the time of manufacture, and improved the quality.

In order to achieve the above object, the present invention provides at least one surface of a lens sheet including a lens layer in which convex lenses formed in one axial direction are adjacent and arranged on a substantially entire surface, and a first support layer for supporting the lens layer. And / or a diffusion sheet comprising a diffusion layer and a second support layer for supporting the diffusion layer is laminated on the back surface, and the lens sheet and the diffusion sheet are bonded at at least one or more locations on the circumferential edge. It provides an optical sheet for use.

According to the present invention, the rigidity of the optical sheet for display is improved, and the above problems caused by the protective sheet do not occur, which is advantageous in terms of cost and quality. Moreover, the said problem at the time of laminating | stacking a several layer film, and the said problem by thermal expansion and thermal contraction between a some film do not arise either.

According to this invention from the above points, the handling property at the time of manufacture improves, and the quality of the display optical sheet improves.

In addition, transparent films, such as a resin film, are used for a "first support layer" and a "second support layer." Examples of the material of the resin film include polyester, cellulose acylate, acrylic, polycarbonate, polyolefin, PET (polyethylene terephthalate), and the like.

In addition, a lenticular lens and a prism sheet are representative of the lens sheet "a convex lens formed in one axial direction adjacent to and arranged substantially on the entire surface", and other examples include a diffraction grating.

Also, in order to achieve the above object, the present invention provides two lens sheets including a lens layer in which convex lenses formed in one axial direction are adjacent and arranged on a substantially entire surface, and a first support layer for supporting the lens layer. A diffusion sheet including a diffusion layer and a second support layer for supporting the diffusion layer is laminated on the surface and / or the rear surface of the laminate of the lens sheet, in which the axes of the convex lenses are substantially perpendicular to each other. An optical sheet for display is provided, wherein the lens sheets and the lens sheet and the diffusion sheet are bonded to each other at least one or more locations on the circumferential edge thereof.

According to the present invention, the above-described various effects are similarly obtained even when the lens sheets are laminated in a direction orthogonal to the axes of the convex lens, and the diffusion sheet is laminated on the front and / or back surfaces thereof. Therefore, according to this invention, the handleability at the time of manufacture of an optical sheet for display improves, and the quality of an optical sheet for display improves.

In addition, although "the lamination | stacking in the direction orthogonal to the axis of a lens" is called, you may adjust a little amount of an angle for prevention of moire fringes.

In the present invention, the thickness of the first support layer of the lens sheet and the second support layer of the diffusion sheet are each 50 µm, and the thickness of the optical sheet for display is preferably 200 µm or more. In particular, the thickness of the first support layer and the second support layer is preferably 50 to 300 µm, more preferably 80 to 250 µm, and most preferably 100 to 220 µm. The first support layer and the second support layer are preferably in the form of polyethylene terephthalate, respectively.

In the present invention, the difference in refractive index between the first resin contained in the lens layer of the lens sheet and the second resin contained in the diffusion layer of the diffusion sheet is preferably 0.05 or more. This configuration improves the screen brightness.

In the present invention, the difference in thermal expansion coefficient between the first support layer of the lens sheet and the second support layer of the diffusion sheet is preferably within 0.7%, more preferably within 0.5%, and most preferably within 0.3%. By such a configuration, deformation of the sheet due to the thermal expansion difference is suppressed, and durability after mounting of the display device is improved.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on an accompanying drawing. First, the structure of the example (1st-6th embodiment) of the display optical sheet manufactured by the manufacturing method of the display optical sheet which concerns on this invention is demonstrated, and then, the manufacturing method of these display optical sheets (1st 6th manufacturing method) is demonstrated.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the example (1st Embodiment) of the display optical sheet manufactured by the manufacturing method of the display optical sheet which concerns on this invention.

The optical sheet for display 10 includes a first diffusion sheet 12, a first prism sheet 14, a second prism sheet 16, and a second diffusion sheet 18 in this order. It is a module of an optical sheet laminated.

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

A resin film may 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), biaxial stretching Known things such as polyethylene terephthalate, polyethylene naphthalate, polyamideimide, polyimide, aromatic polyamide, cellulose acylate, cellulose triacetate, cellulose acetate propionate and cellulose diacetate can be used. Among these, polyester, cellulose acylate, acrylic, polycarbonate, and polyolefin can be preferably used.

The diameter of the beads of the first diffusion sheet 12 and the second diffusion sheet 18 needs to be 100 µm or less, and preferably 25 µm or less. For example, an average particle diameter can be 17 micrometers in the range of 7-38 micrometers of predetermined distributions.

The first prism sheet 14 and the second prism sheet 16 are lens sheets in which convex lenses formed in one axial direction are adjacent to each other and arranged approximately on the entire surface. The vertex angle of the convex part can be 90 degrees (perpendicular angle) at 25 micrometers.

The first prism sheet 14 and the second prism sheet 16 are arranged in a direction in which the axes of the convex lenses (prisms) are substantially orthogonal. That is, in FIG. 1, the axis of the convex lens of the first prism sheet 14 is disposed perpendicular to the ground, and the axis of the convex lens of the second prism sheet 16 is disposed parallel to the ground. have. In addition, in FIG. 1, in order to understand that the cross section of the 2nd prism sheet 16 is a convex lens, it is shown in a direction different from an actual thing.

The material and manufacturing method of the 1st prism sheet 14 and the 2nd prism sheet 16 can employ | adopt various well-known forms. For example, the transfer roller (the inverted form of the prism sheet is formed on the surface) which rotates the sheet-like resin material pushed out from the die at a speed substantially equal to the extrusion speed of this resin material, and opposes this transfer roller The manufacturing method of the resin sheet which transfers between the nip roller plates arrange | positioned and rotated at the same speed and transfers the uneven | corrugated shape of the surface of a transfer roller to a resin material can be employ | adopted.

In addition, a method of producing a resin sheet in which a transfer plate (stamper) in which an inverted form of a prism sheet is formed on a surface and a resin plate is laminated by hot pressing and press-molded by thermal transfer can be employed.

As the 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 resins, polyvinyl chloride resins (PVC), thermoplastic elastomers or copolymers thereof, cycloolefin polymers and the like are exemplified.

In addition, as another manufacturing method, irregularities are formed on the surfaces of transparent films (polyester, cellulose acylate, acrylic, polycarbonate, polyolefin, etc.) as used in the first diffusion sheet 12 and the second diffusion sheet 18. The manufacturing method of the resin sheet which transfer-forms the unevenness | corrugation of the surface of the roller (the inverted form of prism sheet is formed in the surface) can be employ | adopted.

More specifically, the adhesive and the resin are sequentially applied to the surface to continuously run a transparent film formed of two or more layers of the adhesive layer and the resin layer (for example, UV curable resin), and the unevenness of rotating the transparent film. A method of manufacturing a concave-convex sheet to wind up the concave-convex surface of the concave-convex roller surface to the resin layer, and harden the resin layer (for example, UV irradiation) while the transparent film is wound around the concave-convex roller may be employed. Can be. In addition, the adhesive may be omitted.

In addition, the manufacturing method of the 1st prism sheet 14 and the 2nd prism sheet 16 is not limited to the above example, As long as it is a method which can form a desired uneven | corrugated shape on a surface, other manufacturing methods can also be employ | adopted. have.

As shown in FIG. 1, the left and right ends of the display optical sheet 10 are integrated with each layer by a bonding portion 10A. The bonding portion 10A is formed by carbon dioxide laser processing or the like in the bonding step.

The above-described display optical sheet 10 is disposed between, for example, a light source device and a liquid crystal cell, and used to form a liquid crystal display device as a whole. In this case, various advantages described (at the time of manufacturing the optical sheet for display) In addition to improving the handleability and the quality of the optical sheet for display), the assembling operation of the liquid crystal display element is also very easy.

In addition, it is not limited to the structure of the direct type backlight which arrange | positions a light source device so that a liquid crystal cell may face across the display optical sheet 10, and the side which arrange | positions a light source device in the back surface side of the display optical sheet 10 is not limited. It may be of an edge type (also called side light type or edge light type). The side edge type has lower light utilization efficiency than the direct type, but is thin and has a high degree of brightness uniformity.

In addition, the display optical sheet 10 can be preferably used in liquid crystal display devices such as MVA (Multi-domain Vertical Alignment), IPS (In Plane Switching), OCB (0ptically Compensated Bire fringence), etc. have. In addition, the optical sheet 10 for display may be used in combination with a color filter, a deflection plate, a viewing angle improvement film, or the like.

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

The display optical sheet 20 is an optical sheet formed by stacking the diffusion sheet 12, the first prism sheet 14, and the second prism sheet 16 in order from the bottom. The second diffusion sheet 18 is omitted when a wide diffusion performance such as the optical sheet 10 for display 10 described above is not required.

The optical sheet for display 20 described above is used, for example, between the light source device and the liquid crystal cell to form the liquid crystal display element as a whole, similarly to the first embodiment.

Next, another example (third embodiment) of an optical sheet for display manufactured by the method for producing an optical sheet for display according to the present invention will be described. 3 is a cross-sectional view showing the configuration of an optical sheet for display 30. In addition, the same code | symbol is attached | subjected about the member similar or similar to FIG. 1 (1st Embodiment) and FIG. 2 (1st Embodiment), and the detailed description is abbreviate | omitted.

The optical sheet for display 30 is an optical sheet formed by stacking the first diffusion sheet 12, the prism sheet 14, and the second diffusion sheet 18 in order from the bottom.

This display optical sheet 30 omits the second prism sheet 16 when diffusion performance in the vertical direction is not required for the same surface as the display optical sheet 10 described above.

The optical sheet 30 for display described above is used, for example, between the light source device and the liquid crystal cell to form a liquid crystal display element as a whole, similarly to the first embodiment.

Next, another example (fourth embodiment) of an optical sheet for display manufactured by the method for producing an optical sheet for display according to the present invention will be described. 4 is a cross-sectional view showing the configuration of an optical sheet for display 40. In addition, the same code | symbol is attached | subjected about the member which is the same or 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 obtained by stacking the diffusion sheet 12 and the prism sheet 14 in order from the bottom. When a wide diffusion performance such as the optical sheet for display 10 described above is not required, the second diffusion sheet 18 is omitted, and is perpendicular to the same plane as the optical sheet 10 for display described above. When the diffusion performance is not required, the second prism sheet 16 is omitted.

The optical sheet for display 40 described above is used, for example, between the light source device and the liquid crystal cell to form a liquid crystal display element as a whole, similarly to the first embodiment.

Next, another example (fifth embodiment) of an optical sheet for display manufactured by the method for producing an optical sheet for display according to the present invention will be described. 5 is a cross-sectional view showing the configuration of an optical sheet for display 50. In addition, the same code | symbol is attached | subjected about the member which is the same or 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 formed by stacking the first prism sheet 14, the second prism sheet 16, and the diffusion sheet 18 in order from the bottom. The first diffusion sheet 12 is omitted when a wide diffusion performance such as the optical sheet for display 10 described above is not required.

The optical sheet 50 for display described above is used, for example, between the light source device and the liquid crystal cell to form a liquid crystal display element as a whole, similarly to the first embodiment.

Next, another example (sixth embodiment) 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. 6 is a cross-sectional view showing the configuration of an optical sheet for display 50. In addition, the same code | symbol is attached | subjected about the member which is the same or similar to FIG. 1 (1st Embodiment), FIG. 2 (2nd Embodiment), etc., and the detailed description is abbreviate | omitted.

The optical sheet for display 60 is an optical sheet formed by stacking the first prism sheet 14 and the diffusion sheet 18 in order from the bottom. When a wide diffusion performance such as the optical sheet for display 10 described above is not required, the first diffusion sheet 12 is omitted, and is perpendicular to the same plane as the optical sheet 10 for display described above. When the diffusion performance is not required, the second prism sheet 16 is omitted.

The optical sheet for display 60 described above is used, for example, between the light source device and the liquid crystal cell to form a liquid crystal display element as a whole, similarly to the first embodiment.

Next, the manufacturing method (1st-6th manufacturing methods) of the optical sheet for display is demonstrated. Although this manufacturing method is applicable in common to the above-mentioned display optical sheets 10-60, it demonstrates when it is applied to the display optical sheet (1st Embodiment) of a four-layered constitution for convenience of description. do.

7 is a configuration diagram of an optical sheet manufacturing line 11 for display applied to the first manufacturing method. The rolls 12B, 14B, 16B, and 18B provided at the left end of the drawing each include 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 rolls wound.

The rolls 12B, 14B, 16B, and 18B are axially supported by the rotational shafts of the unwinding means, not shown, respectively, and the first diffusion sheet 12, the first diffusion sheet from the rolls 12B, 14B, 16B, and 18B. The prism sheet 14 of 1, the 2nd prism sheet 16, and the 2nd diffusion sheet 18 are each able to be unwound at about the same speed.

The first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18 which have been unwound are guide rollers G, G ... ) And finally laminated on the upstream side of the laser head 24, which will be described later (lamination step).

As the laser light irradiation apparatus including the laser head 24, a YAG laser irradiation apparatus having a wavelength of 355 to 1064 nm, a semiconductor laser irradiation apparatus, and a carbon dioxide laser irradiation apparatus having a wavelength of 9 to 11 µm can be adopted. Although the oscillation method may be continuous oscillation or pulse oscillation, in order to perform welding at the same time as cutting, the point joining by pulse oscillation is also good in appearance.

The output and frequency required to perform welding (cutting process) at about the same time as the cutting (cutting process) vary depending on the feed speed of the material, the scan speed of the laser light, and the thickness of the material, but the approximate output is 2 to 50W and the frequency is 100 kHz. Good welding results are obtained under the following conditions.

The laser head 24 is attached to an X driving robot axis or an XY driving robot axis which can move in the X direction (sheet width direction) or XY direction, and can perform positioning or arbitrary trajectory movement to an arbitrary position. . The laser head 24 may be moved together with the laser head 24 according to the irradiation pattern of the laser light. However, by guiding only the laser light with an optical fiber with the laser head 24 in a separate arrangement (fixed), the movement mechanism in the XY direction can be simplified.

Moreover, a well-known mechanism (suction apparatus etc.) which sucks the smoke which generate | occur | produces at the time of cutting and welding by the laser head 24 can also be provided.

The laser light is irradiated from the laser head 24 to the cut and / or joining portions at the edges of the laminate, and the edges of the laminate are cut and melted and joined while moving the irradiation spot at a constant speed. .

By the above process, the optical sheet 10 for display (refer FIG. 1) is formed. The cut and bonded display optical sheet 10 is conveyed on the conveyor 26 and stopped. The display optical sheet 10 on the conveyor 26 is sequentially stacked on the integration device 32 by the adsorption lateral transfer device 28.

On the other hand, the laminated body 34 of the sheet | seat in which the display optical sheet 10 was punched by the laser head 24 is wound up to the winding roll 36 of a winding apparatus (not shown in detail).

According to the manufacturing method (1st manufacturing method) of the above-mentioned display optical sheet, the effect of the following 1) -3) is acquired.

1) Effect of reducing damage

If damage occurs on the upper and lower surfaces of the lens sheet (the first prism sheet 14 and the second prism sheet 16), the damage is prominent due to the lens effect. On the other hand, when damage occurs on the lower surface of the diffusion sheet (the first diffusion sheet 12 and the second diffusion sheet 18), light is diffused, so that the damage is inconspicuous. From this, preventing damage to the lens sheet leads to a reduction in damage failure. Although damage often occurs during handling after sheet processing, by combining the lens sheet with the diffusion sheet, the diffusion sheet fulfills the role of the protective sheet, so that failure due to damage can be reduced. In particular, in the optical sheet for display 10 of the first embodiment (see Fig. 1) and the optical sheet for display 30 of the second embodiment (see Fig. 3), in which the lens sheet does not appear on the surface, The effect is great.

2) Reduced number of assembly processes

For example, when assembling the liquid crystal display element, when the display optical sheet 10 (see FIG. 1) of the first embodiment is used, the number of assembling steps is only one step of installing the display optical sheet 10. On the other hand, when using a conventional product, installation of the first diffusion sheet ⇒ peeling off the back protective sheet of the first lens sheet ⇒ peeling the surface protection sheet of the first lens sheet ⇒ installation of the first lens sheet ⇒ second 8 steps are required by peeling the back protective sheet of the lens sheet ⇒ peeling the surface protective sheet of the second lens sheet ⇒ installing the second lens sheet ⇒ installing the second diffusion sheet. Thus, according to the first manufacturing method, a significant reduction in the number of assembling steps can be achieved, and the product cost can be reduced.

3) Reduction effect of protective sheet

The lens sheet is often adhered to the front and back to prevent damage. This protective sheet is to be discarded after the lens sheet is installed and is very useless. 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 optical sheet for display 40 of the fourth embodiment (see FIG. 4) and the optical sheet for display 60 of the sixth embodiment (see FIG. 6). In the optical sheet for display 30 of the third embodiment (see FIG. 3), two protective sheets can be reduced, the optical sheet for display 20 of the second embodiment (see FIG. 2), and In the optical sheet for display 50 of the fifth embodiment (see FIG. 5), three protective sheets can be reduced, and the protective sheet in the optical sheet for display 10 (see FIG. 1) of the first embodiment. We can cut four pieces.

Next, another manufacturing method (second manufacturing method) of the optical sheet for display is demonstrated. 8 is a configuration diagram of an optical sheet manufacturing line 21 for a display applied to the second manufacturing method. In addition, the same code | symbol is attached | subjected about the member similar to or similar to the display optical sheet manufacturing line 11 of FIG. 7 (1st manufacturing method), and the detailed description is abbreviate | omitted.

In the optical sheet manufacturing line 21 for display, dispensers 42, 44, 46 and a punching press device 48 are employed instead of the laser head 24 of the optical sheet manufacturing line 11 for display. .

These dispensers 42, 44 and 46 are supply devices for discharging the adhesive from the tip, respectively. The dispenser 42 supplies adhesive to the surface of the first diffusion sheet 12 to bond the first diffusion sheet 12 and the first prism sheet 14 to the dispenser 44. The adhesive is supplied to the surface of the first prism sheet 14 in order to bond the prism sheet 14 and the second prism sheet 16 to each other. The dispenser 46 is connected to the second prism sheet 16. In order to adhere the second diffusion sheet 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 which is bonded with the help of heat or a catalyst. Specifically, general adhesives such as silicone adhesives, polyurethane adhesives, polyester adhesives, epoxy adhesives, cyanoacrylate adhesives, and acrylic adhesives can be used.

Since the optical sheets 10-60 for display may be used at high temperature, the adhesive which is stable even at normal temperature -120 degreeC is preferable. Among these, epoxy adhesives can be preferably used because they are excellent in strength and heat resistance. Since the cyanoacrylate adhesive is excellent in quickness and strength, it can be used for the production of an efficient display optical sheet. Polyester adhesive is especially preferable because it is excellent in strength and workability.

These adhesives are roughly classified into a thermosetting type, a hot melt type, and a two-liquid mixture type according to the bonding method. Preferably, a thermosetting type or a hot melt type capable of continuous production is used. Even if any adhesive is used, the coating thickness is preferably 0.5 µm to 50 µm.

In addition, it is preferable to provide drying means for drying the adhesive between the downstream press rollers (guide rollers G). There is no restriction | limiting in particular as this drying means, A well-known drying method, for example, drying by warm air or hot air, drying by dehumidified wind, etc. are illustrated.

The dispensers 42, 44, and 46 are attached to an X-driven robot axis or an XY-driven robot axis that can move in the X-direction (sheet width direction) or XY-direction, and can perform positioning or arbitrary trajectory movement to an arbitrary position. It is supposed to be.

The adhesive is supplied from these dispensers 42, 44 and 46 to the to-be-joined part of a laminated periphery edge, and the peripheral edge of a laminated body is bonded by the downstream press roller (guide roller G), conveying a laminated body. .

The punching press device 48 downstream of the dispensers 42, 44, and 46 is a device for cutting the peripheral edge of the laminate to the product size. In this punching press apparatus 48, only the front end of the punched sheet (the optical sheets 10 to 60 for display) or the end of the arbitrary piece is allowed to enter the cutting edge into the central portion of the bonded portion. This bonded composite sheet can be obtained.

Next, another manufacturing method (third manufacturing method) of the optical sheet for display is demonstrated. 9 is a configuration diagram of an optical sheet manufacturing line 31 for display applied to a third manufacturing method. In addition, the same code | symbol is attached | subjected about the member same as or similar to the display optical sheet manufacturing line 11 of FIG. 7 (the 1st manufacturing method), and the display optical sheet manufacturing line 21 of FIG. 8 (the 2nd manufacturing method). And the detailed description thereof is omitted.

In this display optical sheet manufacturing line 21, tape supply apparatuses 52, 54 and 56 are used instead of the dispensers 42, 44 and 46 of the display optical sheet manufacturing line 21. As shown in FIG. These tape feeders 52, 54, and 56 are feeders for feeding double-sided tapes from their respective ends, respectively.

The tape supply device 52 supplies a 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 to each other. 54 is a double-sided tape is supplied to the surface of the first prism sheet 14 to bond the first prism sheet 14 and the second prism sheet 16, the tape supply device 56 The double-sided tape is supplied to the surface of the second prism sheet 16 in order to bond the second prism sheet 16 and the second diffusion sheet 18 to each other.

The double-sided tape supplied from the tape feeders 52, 54, and 56 is an adhesive applied to both surfaces. As the pressure-sensitive adhesive of the double-sided tape, a highly adhesive acrylic copolymer resin can be used, but other adhesives such as silicone, natural rubber, and synthetic rubber can be used, and physical strength such as heat resistance and creep resistance, price, etc. In consideration of this, it is preferable to use an acrylic pressure-sensitive adhesive.

The tape supply devices 52, 54, and 56 which supply double-sided tape can be responded by using a commercially available general-purpose tape dispenser. The tape feeders 52, 54, and 56 are attached to a single axis moving mechanism that can move to any position in the X direction (sheet width direction), and can change the position of double-sided tape sticking according to the punching pattern.

In addition, there is a pivoting mechanism in the fixed portions of the tape feeders 52, 54 and 56, and the tape sticking pattern in the inclined direction by changing the position of the tape feeders 52, 54 and 56 in synchronization with the sheet feed speed. It is a mechanism that can be used.

In the punching press apparatus 48 downstream of the tape supply apparatuses 52, 54, and 56, the sheet punched by making a cutting edge enter the center part of the tape width part adhered (optical sheet 10-60 for display) It is possible to obtain a composite sheet bonded only to the front end of the piece or any end of the piece.

Next, another manufacturing method (fourth manufacturing method) of the optical sheet for display is demonstrated. 10 is a configuration diagram of an optical sheet manufacturing line 41 for display applied to a fourth manufacturing method. In addition, the optical sheet manufacturing line 11 for display 11 of FIG. 7 (the 1st manufacturing method), the optical sheet manufacturing line 21 for display of FIG. 8 (2nd manufacturing method), and FIG. 9 (3rd manufacturing) The same or similar members as those of the optical sheet manufacturing line 31 for display of the method) are denoted by the same reference numerals, and detailed description thereof is omitted.

In this optical sheet manufacturing line 21 for display, ultrasonic horns 62, 64, 66 are employed instead of the dispensers 42, 44, 46 of the optical sheet manufacturing line 21 for display. These ultrasonic horns 62, 64, and 66 are arranged downstream of the press roller (guide roller G), respectively.

The ultrasonic horns 62, 64, and 66 are apparatuses for fusing sheets of two or more laminated sheets. That is, the ultrasonic horn 62 is a fusion of the first diffusion sheet 12 and the first prism sheet 14, the ultrasonic horn 64 is the first prism sheet 14 and the second prism sheet. (16) is fused, and the ultrasonic horn (66) is fused to the second prism sheet (16) and the second diffusion sheet (18).

Ultrasonic horns 62, 64, and 66 (ultrasound welding devices) are conventionally known, and are known in the form of raising and lowering the horn by an air cylinder, and in the form of raising and lowering the horn by a servomotor. Any type of ultrasonic welding device can be applied as long as it is possible to apply ultrasonic vibration while welding sheets.

The position control of the ultrasonic horns 62, 64, and 66 is only a change of position in the width direction of the sheet when the punching pattern is horizontal with respect to the conveying direction of the sheet. However, when the punching pattern corresponds to the obliquely punching pattern, the ultrasonic horn ( 62, 64, and 66 are provided by providing a vibrating mechanism in which the traveling direction can be varied in an arbitrary direction, and moving in the width direction in synchronization with the movement amount of the seat.

The setting conditions of the ultrasonic horns 62, 64, and 66 may be set within a range in which the welded portion is not melted or broken by heat, and if necessary, the bonded portion may be cooled by an air cooling mechanism such as air spraying after adhesion (fusion). .

In the punching press apparatus 48 downstream of the ultrasonic horns 62, 64, and 66, the cutting piece enters the center portion of the bonded fusion portion, so that the entire piece of the punched sheet (the optical sheets for displays 10 to 60). Alternatively, it is possible to obtain a composite sheet bonded only to the end of any piece.

Next, another manufacturing method (fifth manufacturing method) of the optical sheet for display is demonstrated. 11 is a configuration diagram of an optical sheet manufacturing line 51 for display applied to a fifth manufacturing method. In addition, the optical sheet manufacturing line 11 for display 11 of FIG. 7 (the 1st manufacturing method), the optical sheet manufacturing line 21 for display of FIG. 8 (2nd manufacturing method), and FIG. 9 (3rd manufacturing) The same or similar members are denoted by the same reference numerals and the detailed description thereof is omitted.

In the optical sheet manufacturing line 21 for display, laser heads 72, 74, and 76 are employed instead of the ultrasonic horns 62, 64, and 66 of the optical sheet manufacturing line 41 for display. The laser heads 72, 74, and 76 are disposed downstream of the press rollers (guide rollers G), similarly to the ultrasonic horns 62, 64, and 66, respectively.

The laser heads 72, 74, and 76 are apparatuses for fusing sheets in which two or more sheets are laminated, similarly to the ultrasonic horns 62, 64, and 66. That is, the laser head 72 fuses the first diffusion sheet 12 and the first prism sheet 14, and the laser head 74 connects the first prism sheet 14 and the second prism. The sheet 16 is fused, and the laser head 76 is fused to the second prism sheet 16 and the second diffusion sheet 18.

In addition, the laser heads 72, 74, and 76 are used only for the bonding process, unlike the laser head 24 in the display optical sheet manufacturing line 11 of FIG. 7 (the first manufacturing method), and the cutting process is punching. It is performed by the press apparatus 48. However, the basic specifications of the laser heads 72, 74, and 76 and the surrounding configuration are substantially the same as in the first manufacturing method.

The setting conditions of the laser heads 72, 74, and 76 may be set within a range in which the welded portion is not melted or broken by heat, and if necessary, the bonded portion may be cooled by an air cooling mechanism such as air spraying after adhesion (fusion). .

In the punching press apparatus 48 downstream of the laser heads 72, 74, and 76, the cutting piece enters the center part of the bonded fusion | bonded part, and the front piece of the punched sheet | seat (display optical sheets 10-60). Alternatively, it is possible to obtain a composite sheet bonded only to the end of any piece.

Next, another manufacturing method (sixth manufacturing method) of the optical sheet for display is demonstrated. 12 is a configuration diagram of an optical sheet manufacturing line 61 for display applied to a sixth manufacturing method. In addition, the optical sheet manufacturing line 11 for display 11 of FIG. 7 (the 1st manufacturing method), the optical sheet manufacturing line 21 for display of FIG. 8 (2nd manufacturing method), and FIG. 9 (3rd manufacturing) The same or similar members are denoted by the same reference numerals and the detailed description thereof is omitted.

In the optical sheet manufacturing line 21 for display, one laser head 78 is employed instead of the three laser heads 72, 74 and 76 of the optical sheet manufacturing line 51 for display. This laser head 78 is arrange | positioned downstream of a press roller (guide roller G).

This laser head 78 is a device for fusing two or more laminated sheets. That is, the laser head 78 fuses a laminate of the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second diffusion sheet 18. .

In addition, the laser head 78 is used only for the bonding process unlike the laser head 24 in the display optical sheet manufacturing line 11 of FIG. 7 (the first manufacturing method), and the cutting process is the punching press apparatus 48. ) Is performed. However, the basic specification of the laser head 78 and the configuration of the surroundings are substantially the same as in the first manufacturing method.

The setting conditions of the laser head 78 may be set within a range in which the welded portion is not melted or broken by heat, and if necessary, the bonded portion may be cooled by an air cooling mechanism such as air spraying after adhesion (fusion).

In the punching press apparatus 48 downstream of the laser head 78, the cutting edge enters the center portion of the bonded fusion portion, or the entire piece of the punched sheet (the optical sheets 10 to 60 for display) or any convenience. A composite sheet bonded only at the end can be obtained.

Next, a sheet punched 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 (optical for display) The planar arrangement of the sheets 10 to 60 will be described.

FIG. 13 is a view for explaining the planar arrangement of the sheets (display optical sheets 10 to 60) punched from the laminate in the first manufacturing method, and FIG. 14 is a lamination in the second to sixth manufacturing methods. It is a figure explaining the planar arrangement of the sheet | seat punched out of a sieve (optical sheets 10-60 for display).

In FIG. 13, (A) shows the state which performs fusion (bonding process) and punching (cutting process) parallel with respect to the conveyance direction of a laminated body, (B) has melted in the diagonal direction with respect to the conveyance direction of a laminated body. (Joining process) and punching (cutting process) are shown. In the figure, the point of the circumferential edge of the sheet punched from the laminate shows a fusion point.

In FIG. 14, (A) shows the state which performs fusion | melting or gluing (bonding process) in the direction parallel and orthogonal with respect to the conveyance direction of a laminated body, (B) is fusion | melted in the diagonal direction with respect to the conveyance direction of a laminated body. Or the state which performs an adhesion (bonding process) is shown. In the figure, the point of the peripheral edge part of the sheet punched from the laminated body represents a fusion point or adhesion point.

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

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

1) Improvement of product value by reducing cost and thickness

Since the optical sheet used for a large size liquid crystal television requires rigidity, the thickness of the support body about 2 times thicker than before is used, respectively. However, since the optical sheet according to the present invention is a composite of sheets, it is possible to have sufficient rigidity without increasing the thickness of each sheet, so that the thickness of each layer can be reduced.

2) Improving performance by preventing the reduction of condensing effect

Some products are matted on the back side to prevent damage to the lens sheet. In the optical sheet according to the present invention, there is no need to reduce production costs, and the light collecting effect can be prevented from being reduced by the matte treatment, thereby improving performance.

As mentioned above, although each example of embodiment of the manufacturing method of the optical sheet for displays which concerns on this invention was demonstrated, this invention is not limited to the example of the said embodiment, A various form can be employ | adopted.

For example, in the example of this embodiment, in any case, although the prism of the 1st prism sheet 14 and the 2nd prism sheet 16 is upward, this prism can also be laminated downward and laminated | stacked. .

In addition, the layer structure of the optical sheet for a display is not limited to the example of embodiment, For example, a protective sheet can also be laminated | stacked on the upper and lower surfaces.

This is because the same configuration as described above works even in the present embodiment, and the same effect can be obtained.

<< Example >>

[Production of Prism Sheet]

The prism sheet used for the 1st prism sheet 14 and the 2nd prism sheet 16 was manufactured. This prism sheet is used in common with the first prism sheet 14 and the second prism sheet 16.

Adjusting the balance

The compound shown in the table of FIG. 15 was mixed by the weight ratio described, it heated at 50 degreeC, was stirred, and dissolved, and the resin liquid was obtained. In addition, the name and content of each compound are as follows.

EB3700: Evercryl 3700, manufactured by Daicel UC Co., Ltd.

       Bisphenol A type epoxy acrylate,

       (Viscosity: 2200mPa · s / 65 ℃)

BPE200: NK ester BPE-200, product made by Shinnakamura Kagaku Corporation,

       Ethylene oxide addition bisphenol A methacrylic acid ester,

       (Viscosity: 590mPa · s / 25 ℃)

BR-31: new frontier BR-31, Daiichichigo Seiyaku High School

      Tribromophenoxyethyl acrylate,

      (Solid at room temperature, melting point above 50 ℃)

LR8893X: Lucirin LR8893X, a drum radical generator made by BASF,

       Ethyl-2,4,6-trimethylbenzoylethoxyphenylospinoxide

MEK: Methyl ethyl ketone

The prism sheet was manufactured using the manufacturing apparatus of the prism sheet of the structure shown in FIG.

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

As the emboss 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. The groove | channel with 50 micrometers of pitches in the roller axial direction was formed by the cutting process which used the diamond bite (single point) in the perimeter of about 500 mm width of the surface of a roller. The cross section of the groove is a triangular shape with a vertex angle of 90 degrees, and the bottom of the groove is a triangular shape of 90 degrees without a flat portion. That is, the groove width is 50 mu m and the groove depth is about 25 mu m. Since this groove is infinitely seamless in the circumferential direction of the roller, the lenticular lens (prism sheet) having a triangular cross section can be formed on the sheet W by the emboss roller 83. Nickel plating was performed on the surface of the roller after groove processing.

As the coating means 82, a die coater using an extrusion type coating head 82C was used.

The liquid of the composition shown in the table of FIG. 15 was used as coating liquid F (resin liquid). In the wet state of the coating liquid F (resin), the supply amount of the coating liquid F to the coating head 82C was controlled by the supply device 82B so that the film thickness after drying the organic solvent became 20 µm.

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

As the nip roller 84, a roller having a diameter of 200 mm and having a layer of silicone rubber having a rubber hardness of 90 on the surface was used. The nip pressure (effective nip pressure) which presses the sheet | seat W with the emboss roller 83 and the nip roller 84 was 0.5 kPa.

The metal halide lamp was used as the resin hardening means 85, and irradiation was performed with energy of 1000 mJ / cm 2.

By the above, the prism sheet in which the uneven | corrugated pattern was formed was obtained.

Thus, the thermal expansion rate of the support body (polyethylene terephthalate) of the prism sheet obtained was 0.3%. Moreover, the refractive index of resin used for the lens part was 1.570.

[Production of First Diffusion Sheet 12]

The first diffusion sheet 12 (lower diffusion sheet) was produced by forming each layer by the following methods in order of a primer layer, a backcoat layer, and a light-diffusion layer.

Primer layer

On one side of a polyethylene terephthalate film (support) having a thickness of 100 μm, A liquid as a coating liquid for a primer layer having the following composition was applied with a wire bar (wire size: # 10), dried at 120 ° C. for 2 minutes, and the film thickness was 1.5. A primer layer having a thickness was obtained.

(Coating liquid for primer layer)

Methanol 4165g

Jurimer SP-50T (made by Nippon Kayaku Co., Ltd.) 1495 g

Cyclohexanone 339 g

Jurimer MB-1X (made by Nippon Kayaku Co., Ltd.) 1.85 g

  (Organic particle: Polymethyl methacrylate crosslinked type, spherical ultrafine particles having a weight average particle diameter of 6.2 μm)

Backcoat layer

B liquid as a coating liquid for a backcoat layer of the following composition was apply | coated to the surface of the said support body on the opposite side to which the primer layer was apply | coated with the wire bar (wire size: # 10), it dried at 120 degreeC for 2 minutes, and the film thickness is 2.0 micrometers. A backcoat layer was obtained.

(Coating liquid for back coat layer)

Methanol 4171g

Juicy Creamer SP-65T (made by Nippon Kayaku Co., Ltd.) 1487 g

Cyclohexanone 340 g

Jurimer MB-1X (made by Nippon Kayaku Co., Ltd.) 2.68 g

   (Organic particle: Polymethyl methacrylate crosslinked type, spherical ultrafine particles having a weight average particle diameter of 6.2 μm)

Light Diffusion Layer

On the primer layer side of the support body created above, C liquid as a coating liquid for light-diffusion layer of the following composition was apply | coated with the wire bar (wire size: # 22), and it dried at 120 degreeC for 2 minutes, and obtained the light-diffusion layer. Moreover, although mentioned later, this light-diffusion layer was apply | coated immediately after preparing C liquid, and the thing apply | coated after adjusting C liquid for 2 hours and obtained respectively was obtained.

(Coating Liquid for Light Diffusion Layer)

20.84 g of cyclohexanone

Disparon PFA-230 Solid Concentration 20% by mass 0.74g

 (Particle sedimentation inhibitor: fatty acid amide, product made by Kusumoto Kasei)

17.85 g of 20 mass% methyl ethyl ketone solutions of acrylic resin (DIALAL BR-117, Mitsubishi Rayon Corporation make)

Juicy Creamer MB-20X (made by Nippon Kayaku Co., Ltd.) 11.29 g

  (Organic particle; Polymethyl methacrylate crosslinking type, spherical ultrafine particle of 18 micrometers of weight average particle diameters)

0.03 g of F780F (made by Dainippon Ink, Inc.)

  (Methyl ethyl ketone 30% by mass solution)

[Production of Second Diffusion Sheet 18]

The same conditions and the same flow as those of the first diffusion sheet 12 above, except that the amount of addition of the jurimer MB-20X in the light diffusion layer of the first diffusion sheet 12 was changed from 11.29 g to 1.13 g. The second diffusion sheet 18 (upper diffusion sheet) was produced.

The thermal expansion coefficient of the support body (polyethylene terephthalate) of the diffusion sheet (1st diffusion sheet 12 and 2nd diffusion sheet 18) obtained in this way was 0.35. Moreover, the refractive index of resin in the light-diffusion layer was 1.490.

[Creation of optical sheet 10 for display: Example]

Using each of the above sheets, the first diffusion sheet 12, the first prism sheet 14, the second prism sheet 16, and the second shown in Fig. 1 described above in order from the bottom. The optical sheet for display 10 (module of an optical sheet) in which the diffusion sheet 18 was laminated was manufactured.

As the manufacturing apparatus, the display optical sheet manufacturing line 11 (1st manufacturing method) shown by FIG. 7 mentioned above was used. As the laser light irradiation apparatus including the laser head 24, a carbon dioxide laser irradiation apparatus was used. The wavelength is 10 mu m, the output is 25 W, and the frequency is 50 Hz.

The manufacturing method of the display optical sheet 10 was made by cutting | disconnecting 4 edges of a laminated body by laser light irradiation, and joining 4 sides of 4 edges.

[Manufacture of Optical Sheet for Display: Comparative Example]

<Comparative Example 1>

Instead of the polyethylene terephthalate film having a thickness of 100 µm, a diffusion sheet (the first diffusion sheet 12 and the second diffusion sheet 18) and a prism sheet, each made of a polyethylene terephthalate film having a thickness of 25 µm as a support, respectively Using the first prism sheet 14 and the second prism sheet 16, an optical sheet for display of the first comparative example was manufactured. The thickness of the optical sheet for display of a 1st comparative example was 160 micrometers. In addition, the optical sheet for display of an Example was 380 micrometers.

<Comparative Example 2>

A prism sheet (first prism sheet 14) obtained by using a liquid (liquid viscosity: 300 m · ㎩, refractive index 1.508) of the composition shown in the table of FIG. 17 as a resin liquid instead of the liquid of the composition shown in the table of FIG. Using the second prism sheet 16), an optical sheet for display of the second comparative example was manufactured. In addition, the same thing as Example was used for the diffusion sheet (1st diffusion sheet 12 and 2nd diffusion sheet 18).

The difference of the refractive index of the resin of the diffusion layer used for a diffusion sheet, and the resin used for the lens part of a prism sheet was 0.018 in the 2nd comparative example, compared with the Example which was 0.08.

<Comparative Example 3>

As a support for the diffusion sheet (the first diffusion sheet 12 and the second diffusion sheet 18), a polyethylene terephthalate film having a thermal expansion coefficient of 1.07% was used, and a prism sheet (first prism sheet 14). The optical sheet for display of a 3rd comparative example was manufactured using the polyethylene terephthalate film whose thermal expansion rate is 0.3% as a support body of the 2nd prism sheet 16). The difference of the thermal expansion coefficient of the support body used for a diffusion sheet was 0.77 compared with the Example being 0.05.

[Evaluation of Optical Sheet for Display]

<Evaluation 1>

100 sets of optical sheets for display of Examples and First Comparative Example were evaluated, respectively, and the presence or absence of damage occurring during handling was evaluated. When the bright line by damage was visually recognized, it was set as NG. Of the 100 sets of the examples, NG was only one set. On the other hand, among 100 sets of the comparative example, NG was 75 sets.

According to the Example of this invention from the above comparison result, it confirmed that the rigidity of the sheet | seat improves and the handleability at the time of manufacture improves.

<Evaluation 2>

The optical sheet for display of Example and 2nd comparative example was respectively installed in commercially available TV, and the brightness was measured, and the Example was 16600 cd / m <2>. On the other hand, the second comparative example was 15500 cd / m 2.

From the above comparative result, according to the Example of this invention, it confirmed that brightness was improved.

<Evaluation 3>

After putting the optical sheet for displays of an Example and the 3rd comparative example into the oven of 85 degreeC, respectively, for 24 hours, it installed in the liquid crystal device, and evaluated the presence or absence of these deformation | transformation. The example could be marked as normal because there was no deformation in the sheet. On the other hand, in the third comparative example, deformation was observed, resulting in poor display.

According to the Example of this invention from the above comparison result, it was confirmed that the deformation | transformation of the sheet | seat by a thermal expansion difference can be suppressed, and the durability after assembly of a display apparatus improves.

As described above, according to the present invention, the handleability at the time of manufacture can be improved and a high quality optical sheet for display can be provided.

Claims (6)

The diffusion layer and the diffusion layer are provided on at least one surface and / or the rear surface of the lens sheet including a lens layer having a convex lens formed in one axial direction adjacent to the entire surface and a first support layer for supporting the lens layer. A diffusion sheet comprising a second supporting layer to support is laminated, and the lens sheet and the diffusion sheet are bonded at one or more locations on the circumferential edge thereof. Two lens sheets each having a convex lens formed in one axial direction adjacent to each other and having a lens layer arranged on a substantially entire surface and a first support layer for supporting the lens layer are laminated in a direction in which the axes of the convex lenses are substantially orthogonal. A diffusion sheet comprising a diffusion layer and a second support layer for supporting the diffusion layer is laminated on the surface and / or the rear surface of the stack of lens sheets, wherein the lens sheets and the lens sheet and the diffusion sheet are surrounded by An optical sheet for display, which is bonded at one or more locations on the edges. The thickness of each of the said 1st support layer and said 2nd support layer is 50 micrometers or more, The optical sheet for display, characterized in that the thickness of the display optical sheet is 200㎛ or more. 4. The optical sheet for display according to claim 3, wherein the first support layer and the second support layer are polyethylene terephthalate films. The lens layer according to any one of claims 1 to 4, wherein the lens layer contains a first resin, The diffusion layer contains a second resin, And a difference in refractive index between the first resin and the second resin is 0.05 or more. The optical sheet for display according to any one of claims 1 to 5, wherein a difference in thermal expansion coefficient between the first support layer and the second support layer is within 0.7%.

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