JP2009042633A - Layered product of optical sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a layered product of optical sheets, preventing the occurrence of bending or flexure due to a temperature change caused by lighting of a backlight even if optical sheets different in coefficient of thermal expansion are stacked. <P>SOLUTION: This layered product 1 of optical sheets includes two or more optical sheets 2, and two or more connecting parts 3 provided at the peripheral edge parts thereof to connect the optical sheets 2 to each other, wherein each connecting part 3 has a sliding mechanism capable of sliding the optical sheets 2 in one direction, the sliding directions of the connecting parts 3 are all set to pass the central point 6 of radiation to be radial as a whole, and the connecting parts 3 are provided on two or more sides of the layered product 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminate of optical sheets to be mounted on the surface of a light emitting member such as a backlight for a liquid crystal display device, and more specifically, even when optical sheets having different coefficients of thermal expansion are laminated, it is bent or bent due to temperature changes. The present invention relates to a laminate of optical sheets that is free from distortion and has no distortion or surface unevenness due to a difference in thermal expansion.

  In recent years, liquid crystal display devices have been used in various fields, and various performances are required depending on the respective applications. For office automation equipment, personal computers, word processors, etc., there are strong demands for weight reduction, thinning, high definition, and power saving. Furthermore, for liquid crystal display devices, a wider field of view, wider screen, and higher brightness are required. The demand is getting stronger.

  In order to meet these requirements, the light emitted from a light emitting member such as a backlight is diffused according to the application, or the directivity of the light is changed, that is, the light in an unnecessary direction is redirected. In order to condense on the front, it is common to use a film or sheet having an optical function (hereinafter collectively referred to as an optical sheet).

In addition, since a desired optical function cannot usually be obtained with a single optical sheet, a plurality of optical sheets are used in an overlapping manner. However, if a plurality of optical sheets are attached to the light emitting member one by one, the number of steps increases, leading to an increase in cost. Therefore, each optical sheet is bonded in advance with an adhesive or the like. As shown in FIG. 2, the use of a laminate in which a plurality of sheets are stacked has been proposed.
In addition, the laminated body of Patent Document 1 is such that the product-sized laminated body in which two or more types of optical sheets are laminated in a predetermined order is packaged in a packaging member, and the packaging member is in close contact with the laminated body. It is a packaging body of an optical sheet for a display, which is sealed in a state where the material is decompressed, and the laminated body of Patent Document 2 is formed by laminating two or more optical sheets by electrostatic force. This is an optical sheet for display.

  However, when optical sheets with different coefficients of thermal expansion are bonded with an adhesive or the like, a temperature change occurs in the laminate due to heat emitted from a light emitting member such as a backlight, and each optical sheet thermally expands at a different rate. It is inevitable that the body bends or bends and distortion and display unevenness occur. Then, although the laminated body is manufactured using the optical sheet with a substantially equal coefficient of thermal expansion, in this case, it becomes impossible to design a laminated body freely and it becomes difficult to obtain desired optical performance.

  Moreover, when the optical sheet is packaged with another material to form a laminated body as in Patent Document 1, the pressure in the packaging bag changes due to heat generated from the light emitting member. Therefore, while the temperature is low, the air pressure from the outside of the packaging bag is too large, the optical sheets in the laminate are strongly pressed, and the optical sheets do not slide with each other. On the other hand, when the temperature rises, the air in the packaging bag expands and the pressure by the air pressure becomes insufficient, and the optical sheet may swing in the packaging bag. Therefore, it is necessary to determine the optimum air pressure inside the packaging bag by calculating backward from the temperature change at the place of use, but this cannot be realized because there is no optimum air pressure in an environment where the temperature change is severe. In addition, since light emitted from the light emitting member is partially reflected between the packaging material layer and the optical sheet layer, there is a problem that light transmittance is reduced.

Furthermore, when the optical sheet is bonded with static electricity as in Patent Document 2, the adhesive force due to static electricity is reduced over time and eventually the optical sheet is peeled off, which may shorten the service life. . On the other hand, when strong static electricity is applied to extend the service life, dust in the air is attracted and the light transmittance decreases.
JP 2007-76666 A JP 2007-78880 A

  In view of such circumstances, the present invention solves the problems of the prior art, and even if an optical sheet having a different coefficient of thermal expansion is used, desired optical performance can be obtained freely, and it can be bent even if the temperature changes significantly. An object of the present invention is to provide a laminated body of optical sheets that can prevent distortion and display unevenness due to temperature changes without being bent or bent, and that does not deteriorate light transmittance and has a long service life.

  The present invention has been made to achieve the above object, and claim 1 of the present invention comprises a laminate comprising two or more optical sheets and having two or more connecting portions for connecting these optical sheets to the peripheral portion thereof. In addition, each connecting portion has a sliding mechanism that can slide the optical sheet in one direction, and all the sliding directions of the connecting portions are made to pass through the radial center point to be radial as a whole. In addition, the connecting portion includes a laminated body of optical sheets characterized by being provided on two or more sides of the laminated body.

  According to a second aspect of the present invention, there is provided a laminated body of optical sheets according to the first aspect, wherein a radiation center point is provided at a corner of the laminated body.

  According to a third aspect of the present invention, there is provided a laminated body of optical sheets according to the first aspect, wherein a radiation center point is provided at a central portion of the laminated body.

  According to a fourth aspect of the present invention, the sliding structure of the connecting portion is provided with a sliding pin having an enlarged diameter portion at both ends thereof and communicating with each optical sheet, and is narrower than the enlarged diameter portion and the sliding pin is inserted. The laminated body of optical sheets according to any one of claims 1 to 3, wherein the laminated body is a substantially elongated rectangular long hole.

  According to the fifth aspect of the present invention, a concave portion having a depth wider than the diameter of the diameter-enlarged portion of the sliding pin and having a substantially longer rectangular shape and having a depth greater than or equal to the height of the diameter-enlarged portion is provided. In addition, the laminated body of the optical sheet according to claim 4, wherein a long hole is provided in the concave portion.

  According to a sixth aspect of the present invention, the sliding structure of the connecting portion is provided upright from one optical sheet and provided in communication with the upright pin having an enlarged diameter portion at the tip and the other optical sheet. The optical sheet laminate according to any one of claims 1 to 3, wherein the optical sheet laminate comprises a substantially long rectangular slot that is narrower than the diameter of the expanded portion and into which the standing pin is inserted. Content.

  According to a seventh aspect of the present invention, a recessed portion having a depth wider than the diameter of the enlarged diameter portion of the standing pin and having a substantially longer rectangular shape is deeper than the height of the enlarged diameter portion. In addition, a long hole is provided in the concave portion, and the laminated body of the optical sheet according to claim 6.

  Claim 8 of the present invention is composed of three or more optical sheets, and the optical sheets used for the surface layer and the back layer have substantially the same thermal expansion coefficient, and the sliding structure of the connecting portion is for the surface layer and the back surface. Standing from one of the optical sheets for the layer, the standing pin fixed to the other optical sheet, and the substantially long length that is inserted into the other optical sheet. It consists of a rectangular long hole, The content is the laminated body of the optical sheet in any one of Claims 1-3 characterized by the above-mentioned.

The optical sheet laminate of the present invention (hereinafter sometimes simply referred to as “laminate”) has a sliding mechanism in which each connecting portion can slide the optical sheet in one direction, and the sliding of the connecting portion. All moving directions pass through the radiation center point, and as a whole, the connecting part slides radially around the radiation center point, so even if optical sheets with different thermal expansion coefficients are stacked, the temperature Along with the change, the optical sheet expands and contracts radially around the radiation center point and absorbs the difference in thermal expansion coefficient, so the laminate does not bend or bend as a whole, and the thermal expansion coefficient Distortion and display unevenness due to the difference are prevented.
Moreover, since the connection part is provided in two or more sides of this laminated body, an optical sheet does not roll up from a laminated body during use, but exhibits stable optical performance.
Furthermore, by increasing the sliding length of the connecting portion, it is possible to easily obtain a laminated body that absorbs the difference in the coefficient of thermal expansion due to a large temperature change and does not bend or bend.

When the radiation center point is provided at the corner of the laminate, the connecting portion provided on the two sides including the corner is parallel to the direction of the side, so that the space for providing the connecting portion is small. A generally compact optical sheet laminate can be obtained.
In addition, when the radiation center point is provided at the center of the laminate, the optical sheet hardly slides at the center of the screen where it is most likely to draw attention in a liquid crystal display, and the distance between the radiation center point and each connection point is not limited. Since the total is minimized and the sliding distance of each connection point associated with the expansion and contraction of the optical sheet is also minimized, the fluctuation of the screen during the expansion and contraction of the optical sheet is minimized and the image quality is improved.

If the sliding structure of the connecting part is composed of a sliding pin and a substantially elongated rectangular long hole provided in communication with each optical sheet, the sliding pin can move substantially linearly along the elongated hole. Even if the optical sheet expands and contracts due to the above, each optical sheet slides in the long axis direction of the long hole and absorbs the difference in thermal expansion coefficient, so that the laminated body is not bent or bent.
In addition, since the diameter of the enlarged diameter part provided in the both ends of the sliding pin is larger than the width | variety of a long hole, it connects so that each optical sheet may not remove | deviate by these. Further, the laminated body is provided with a concave portion that is wider than the diameter of the enlarged diameter portion of the sliding pin and is substantially long and has a depth greater than or equal to the height of the enlarged diameter portion. If a long hole is provided in the inside, the enlarged diameter portion is immersed in the inside of the concave portion, so that a laminate having a substantially flat surface and back surface can be obtained.

When the sliding structure of the connecting portion is constituted by a standing pin standing upright from one optical sheet and a substantially long rectangular slot provided in communication with the other optical sheet, the standing pin extends along the slot. Since the optical sheet can move substantially linearly, each optical sheet can slide in the long axis direction of the long hole even if the optical sheet expands or contracts due to a temperature change.
In addition, since the diameter of the enlarged diameter part provided in the front-end | tip of a standing pin is larger than the width | variety of a long hole, it connects so that each may not remove | deviate from these. In addition, the laminated body is provided with a concave portion having a width wider than the diameter of the enlarged portion of the connecting pin and having a substantially long rectangular shape and a depth equal to or greater than the height of the enlarged portion. When a long hole is provided in the interior, the enlarged diameter portion is immersed in the recessed portion, so that a laminate having a substantially flat front surface and back surface can be obtained.

  The sliding structure of the connecting portion is erected from one of the optical sheets for the front surface layer and the rear surface layer, and its leading end is fixed to the other optical sheet and communicates with the other optical sheets. Since the upright pins can move substantially linearly along the long holes, even if the optical sheet expands and contracts due to temperature changes, The optical sheet can slide in the long axis direction of the long hole. In addition, since the thermal expansion coefficients of the optical sheet for the front surface layer and the optical sheet for the back surface layer are substantially equal, even if the tip of the upright pin is fixed to the other optical sheet, bending due to temperature change does not occur.

  Hereinafter, although the laminated body of the optical sheet in this invention is demonstrated based on a preferable Example, this invention is not limited only to these Examples.

Example 1
If the outline | summary of the laminated body of this invention is demonstrated based on Example 1 described in FIGS. 1-4, this invention will consist of two or more optical sheets 2 (5 sheets of 2a-2e in a present Example). The laminated body 1 has two or more connecting portions 3 for connecting the optical sheets 2 to the peripheral portion thereof, and each connecting portion 3 has a sliding mechanism capable of sliding the optical sheet in one direction. The sliding direction of the portion 3 (shown by the alternate long and short dash line in FIG. 1) passes through the radiation center point 6 and is made radial as a whole, and the connecting portion 3 is provided on two or more sides of the laminate 1. It has been.
In addition, the area | region in the square marked with the broken line in FIG. 1 shows the range through which the light emitted from the light emitting member and emitted from the liquid crystal screen passes. The same applies to FIGS.

  In the present invention, the optical sheet is a general term for various sheets having an optical function, and representative examples include a diffusion sheet, a polarizing plate (polarizing film), various lens sheets (lenticular lens, fly-eye lens (snake eye lens). ), Prism sheet, etc.). Each of these optical sheets can be appropriately used in accordance with the desired optical performance.

In the present invention, as shown in FIG. 2, two or more (five in FIG. 2) optical sheets 2 are laminated to obtain a laminate 1 having desired optical performance. The shape of each optical sheet 2 is not particularly limited, and may be appropriately determined according to the shape and size of the light emitting member to which the laminate 1 is attached.
A connecting portion 3 for connecting the optical sheets 2 to each other is provided at a peripheral portion of the laminate 1 in which the optical sheets 2 are stacked. The number of the connecting portions 3 is not particularly limited and may be appropriately determined in consideration of the size of the laminated body 1 and the like. However, if the arrangement is performed only on one side, the optical sheet 2 is easily turned up and the image quality is deteriorated. Therefore, it is provided over two sides or more, preferably all four sides.

The connecting portions 3 do not fix the respective optical sheets 2, but are loosely connected so that the stacked optical sheets 2 can slide in one direction.
As shown in FIG. 1, the sliding direction of the optical sheet 2 is parallel to the direction of a straight line (indicated by a one-dot chain line) connecting the arbitrarily set radiation center point 6 and the connecting portion 3. Thereby, even when the optical sheets 2 having different thermal expansion coefficients are stacked, each optical sheet 2 expands or contracts according to the respective thermal expansion coefficient around the radiation center point 6. Since the difference in coefficient of thermal expansion is absorbed, the laminate 1 is not bent or bent.
In addition, since the optical sheet 2 is used in an environment where the temperature difference is particularly large, the sliding length of the connecting portion may be increased because the difference in expansion and contraction increases as the temperature difference during use increases.

The position of the radiation center point 6 can be arbitrarily determined as long as it is on a plane including the optical sheet. In principle, the radiation center point 6 can be provided outside the laminate 1. The longer the distance between them, the longer the sliding distance of the optical sheet 2 due to the difference in thermal expansion coefficient, and it becomes difficult to absorb the difference in thermal expansion coefficient, and the fluctuation of the screen due to the sliding of the optical lens 2 also becomes larger. Therefore, it is preferable to provide the radiation center point 6 inside the laminate 1.
From the viewpoint of shortening the sliding distance of the optical sheet 2 due to the difference in thermal expansion coefficient, the radiation center point 6 is preferably provided at the center of the laminated body 1 and does not contribute to the adjustment of the light emitted from the light emitting member ( From the viewpoint of minimizing the area of the optical sheet 2 on which the connecting portion 3 is provided), it is preferable to provide the radiation center point 6 at the corner and to provide the connecting portion 3 on the side including the corner.
In addition, since the optical sheets 2 do not slide with each other regardless of the difference in thermal expansion coefficient at the radiation center point 6, a range of about several millimeters in radius with respect to the radiation center point 6 (depending on the thickness of the optical sheet 2, etc.). However, the laminate 1 does not bend or bend even if it is fixed with an adhesive or the like. Therefore, the radiation center point 6 can be provided on one side of the peripheral portion of the optical sheet 2 and bonded thereto with an adhesive or the like, and the connecting portion 3 can be provided on the other side.
Note that, as described above, the sliding distance of the optical sheet 2 in the connecting portion 3 is longer as the distance from the radiation center point 6 is longer. It is preferable to set the length longer in proportion to the distance from the radiation center point 6 so that it can be done.

In the present invention, the sliding mechanism of the connecting portion 3 is not particularly limited, and any structure can be adopted as long as the connecting portion 3 slides in one direction.
For example, as shown in FIG. 2 to FIG. 4, a substantially long rectangular long hole 4 communicating with the optical sheet 2 is provided, and a sliding pin 5 is inserted into the long hole 4. The structure is such that the moving pin 5 can slide in one direction within the long hole 4 and the enlarged diameter portions 5a are provided at both ends of the sliding pin 4a so that the sliding pin 5 does not fall out of the long hole 4. Can be mentioned.
However, in the present invention, a substantially long rectangle means a shape in which an inserted pin or the like can move in a substantially straight line over a certain distance.

In the first embodiment, the sliding pin 5 has a headed pin 8a having an enlarged diameter portion 5a at one end and a recess for fitting at the other end, and an enlarged diameter portion 5a at one end. A headed pin 8b having a fitting projection on the other end is used.
By using such a structure, optical sheets 2a to 2e having different coefficients of thermal expansion are used, and even if these optical sheets 2a to 2e expand and contract due to temperature changes, the optical sheet 2 can be moved from the sliding direction. The optical sheet 2a to 2e does not slide at all in the direction perpendicular to each other (see FIG. 3), and the difference in thermal expansion coefficient between the optical sheets 2a to 2e is absorbed by the sliding of the optical sheet 2 in the sliding direction ( (Refer FIG. 4 (a) (b)). At this time, the long pin 4 of the sliding pin 5 remains in communication, and the state in which the optical sheets 2a to 2e are connected by the sliding pin 5 is maintained.

  In addition, since it is more preferable that the surface of the laminated body 1 is flat, it is also possible to provide a concave portion 7 for immersing the enlarged diameter portion 5a of the sliding pin 5 (see FIG. 3). In FIG. 3, the thickness of the optical sheet 2 on the front surface side and the back surface side is set to be equal to or higher than the height of the enlarged diameter portion 5a, and the concave portion 7 is provided only in the optical sheet 2 on the front surface side and the back surface side. However, as another method, only the periphery of the long hole 4 is thinned in the plurality of optical sheets 2, and these are laminated, and then the periphery of the long hole 4 is pressed to dent the entire laminated body 7. Can also be provided.

In addition, the optical sheet 2 used in Example 1 is as follows, respectively, but PET and polycarbonate differ in thermal expansion coefficient, but bending and bending did not occur in the range of 23 ° C to 80 ° C.
2a: PET-based diffusion sheet (trade name: Light-Up 100SXE, manufacturer: Kimoto Co., Ltd.)
2b: Polycarbonate lens sheet (trade name: GTL5000, manufacturer: Goyo Paper Industries Co., Ltd.)
2c: Polycarbonate lens sheet (trade name: GTL6000, manufacturer: Goyo Paper Industries Co., Ltd.)
2d: PET-based diffusion sheet (trade name: BS702, manufacturer: Eiwa Co., Ltd.)
2e: Polycarbonate diffusion sheet (trade name: PC-9391, manufacturer: Teijin Chemicals Ltd.)

Example 2
As shown in FIG. 5, the optical sheet laminate 1 according to Example 2 is the same as Example 1 except that the connecting portions 3 are not provided on the right side and the lower side of the laminate 1.
In this embodiment, the radiation center point 6 is set at the upper left, and the connecting portion 3 is provided only on the left side and the upper side. However, the connecting portion 3 and the radiation center point 6 on the left side are aligned in parallel with the left side. Therefore, the sliding direction of the connecting part 3 on the left side is parallel to the left side of the laminate 1. Similarly, the sliding direction of the connecting part 3 on the upper side is parallel to the upper side of the laminate 1. Therefore, the space required for providing the connecting portion 3 (the space between the inner broken line and the outer solid line in FIG. 5) can be relatively small, and the laminate 1 can be made compact.

Example 3
The optical sheet laminate 1 according to Example 3 is the same as Example 1 except that the connecting portions 3 are not provided on the left and upper sides of the laminate 1 as shown in FIG.
In this embodiment, the radiation center point 6 is set at the upper left, and this portion is firmly fixed by an adhesive, and the right side and the lower side are connected by the connecting portion 3. Therefore, even on the left side and the upper side where the connecting portion 3 is not provided, the optical sheet 2 does not turn up and the image quality does not deteriorate. That is, the same effect is obtained when the entire circumference of the laminate 1 is engaged with a relatively small number of connecting portions 3.

Example 4
As shown in FIG. 7, the optical sheet laminate 1 according to Example 4 is an example except that the radiation center point 6 is provided near the center of the upper side, and the connecting portions 3 are provided on the right side, the left side, and the lower side. Same as 1.
Also in this embodiment, as in the third embodiment, the same effect is obtained when the entire circumference of the laminate 1 is engaged with a relatively small number of connecting portions 3.

Example 5
As shown in FIG. 8, the optical sheet laminate 1 according to Example 5 is the same as Example 1 except that the radiation center point 6 is provided near the center of the laminate and the connecting portions 3 are provided on all sides. It is the same.
In this embodiment, for example, even when the light emitting member is turned on and the temperature of the laminated body 1 is increased, even if the optical sheet 2 is thermally expanded in the central portion of the liquid crystal display that attracts the most attention, Since there is no sliding between the sheets, there is an effect that the screen does not fluctuate.
However, in this embodiment, if the radiation center point 6 is fixed with an adhesive or the like, the optical characteristics in the central part of the liquid crystal display device change from those of other parts, which causes a sense of incongruity. It has not been.

Example 6
As shown in FIGS. 9 and 10, the optical sheet laminate 1 according to Example 6 is provided with standing pins 5 ′ having a diameter-enlarged portion 5 a from the optical sheet 2 e on the back surface layer side as the connecting portions 3. The other optical sheets 2a to 2d are the same as the first embodiment except that a sliding structure in which the long hole 4 is provided is employed. In this embodiment, the upright pin 5 'is formed by press-fitting a cap 8c having an enlarged diameter portion 5a into a rod-like protrusion protruding from the optical sheet 2e.
In this example, as in Example 1, optical sheets 2a to 2e having different thermal expansion coefficients are laminated. However, even if the light sheet is heated and expanded due to lighting or the like, FIG. As shown in b), the optical sheets 2a to 2e slide to absorb the difference in coefficient of thermal expansion, so that the laminate 1 is not bent or bent.

Example 7
In the optical sheet laminate 1 according to Example 7, the optical sheet on the surface layer side is changed to the optical sheet 2a ′ having substantially the same thermal expansion coefficient as the optical sheet 2e on the back surface layer side, and FIGS. As shown in FIG. 5, a sliding structure is adopted in which a standing pin 5 'is erected from the optical sheet 2e, its tip is fixed to the optical sheet 2a', and the long holes 4 are provided in the other optical sheets 2b to 2d. The rest is the same as in the first embodiment. The tip of the standing pin 5 'is fixed to the optical sheet 2a' by being press-fitted into a pin receiving hole 5b provided in the optical sheet 2a '.
The optical sheet 2a ′ used in this example is a PET-based diffusion film (trade name: Opulse PBS-072, manufacturer: Eiwa Co., Ltd.).
Also in this example, optical sheets 2a ′ and 2b to 2e having different thermal expansion coefficients are laminated as in Example 1, but even if the sheet is heated and expanded by lighting of the light emitting member, FIG. Since each optical sheet 2a-2e slides like (a) and (b), the difference in thermal expansion coefficient is absorbed and the laminated body 1 is not curved or bent.
Moreover, there exists an advantage that the surface of the laminated body 1 can be made flat, without requiring the fine process of providing the concave part 7 in the thin optical sheet 2. FIG.

  As described above, the laminated body of optical sheets according to the present invention is connected by a connecting portion having a sliding mechanism at the peripheral portion thereof, and the sliding direction passes through the radial center point, and is made radial as a whole. In addition, since the connecting portions are provided on two or more sides of the laminate, even if optical sheets having different coefficients of thermal expansion are used, these optical sheets are centered on the radiation center point as the temperature changes. The difference in coefficient of thermal expansion and expansion is absorbed by the sliding of each optical sheet in the sliding mechanism of the connecting portion, and the laminate is not bent or bent, so that distortion and display unevenness are prevented. The laminate of optical sheets according to the present invention is particularly useful as a laminate of optical sheets to be mounted on the surface of a backlight of a liquid crystal display device.

It is a top view of the laminated body of the optical sheet of Example 1 which concerns on this invention. 3 is an exploded perspective view of a laminated body of optical sheets of Example 1. FIG. It is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 1 perpendicular | vertical with respect to the sliding direction. (A), (b) is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 1 in parallel with respect to the sliding direction. It is a top view of the laminated body of the optical sheet of Example 2 which concerns on this invention. It is a top view of the laminated body of the optical sheet of Example 3 which concerns on this invention. It is a top view of the laminated body of the optical sheet of Example 4 which concerns on this invention. It is a top view of the laminated body of the optical sheet of Example 5 which concerns on this invention. It is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 6 perpendicular | vertical with respect to the sliding direction. (A), (b) is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 6 in parallel with respect to a sliding direction. It is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 7 perpendicular | vertical with respect to the sliding direction. (A), (b) is the schematic sectional drawing which cut | disconnected the sliding mechanism in Example 7 in parallel with respect to a sliding direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical sheet laminated body 2 Optical sheet 3 Connection part 4 Long hole 5 Sliding pin 5 'Standing pin 5a Expanding part 5b Pin receiving hole 6 Radiation center point 7 Recessed part 8a Headed pin 8b Headed pin 8c Cap

Claims (8)

A laminate comprising two or more optical sheets, and having two or more connecting portions for connecting these optical sheets to the peripheral portion thereof,
Each connecting portion has a sliding mechanism capable of sliding the optical sheet in one direction, and all the sliding directions of the connecting portions are made to pass through the radial center point to be radial as a whole. Is provided on two or more sides of the laminate, and is a laminate of optical sheets.   The laminated body of the optical sheet according to claim 1, wherein a radiation center point is provided at a corner of the laminated body.   2. The optical sheet laminate according to claim 1, wherein a radiation center point is provided at a central portion of the laminate. The sliding structure of the connecting part includes a sliding pin having an enlarged diameter part at both ends thereof,
4. The optical device according to claim 1, wherein the optical sheet is provided in communication with each optical sheet, and is formed of a substantially long rectangular slot that is narrower than the diameter-expanded portion and into which the sliding pin is inserted. A laminate of sheets.   The concave portion of the sliding pin is wider than the diameter of the enlarged diameter portion and is substantially long and has a depth greater than the height of the enlarged diameter portion. The optical sheet laminate according to claim 4, wherein the optical sheet laminate is provided in a portion. The sliding structure of the connecting portion is erected from one optical sheet, and a standing pin having an enlarged diameter portion at the tip,
2. An elongated hole having a substantially long rectangular shape, which is provided in communication with another optical sheet and is narrower than the diameter of the enlarged diameter portion of the upright pin and through which the upright pin is inserted. The laminated body of the optical sheet in any one of -3.   It is wider than the diameter of the enlarged diameter portion of the standing pin and is a substantially long rectangular shape. A concave portion whose depth is equal to or larger than the height of the enlarged diameter portion is recessed, and the long hole is formed in the concave portion. The optical sheet laminate according to claim 6, wherein the optical sheet laminate is provided in a portion. It consists of three or more optical sheets,
The optical sheets used for the surface layer and the back layer have substantially the same coefficient of thermal expansion,
The sliding structure of the connecting portion is erected from one of the optical sheets for the front surface layer and the rear surface layer, and the standing pin whose tip is fixed to the other optical sheet;
The optical sheet laminate according to any one of claims 1 to 3, wherein the optical sheet laminate includes a substantially elongated rectangular hole provided in communication with another optical sheet and into which a standing pin is inserted.

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