JP2010230816A - Optical member and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability in shape holding of an optical sheet including a stretched film by suppressing deformation of the optical sheet. <P>SOLUTION: An optical member 4 mounted between a pair of supporting members 3 and 5 of a liquid crystal display device 1 including a light source 2 and the supporting members 3 and 5 includes a porous light diffusing material 41 having holes in a surface 41S farther from the light source 2, an optical sheet 42 including a stretched film, and a substrate 43 in this order from the side of the light source 2 and is so configured that a stress applied to an edge 42E of the optical sheet 42 with the optical member 4 on the liquid crystal display device 1 is ≥0.2 MPa. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical member and a liquid crystal display device.

  Conventionally, in a liquid crystal display device, it is known to provide an optical member including an optical sheet such as a light guide plate, a light diffusion sheet, and a light collecting sheet between a light source and a liquid crystal panel. In such an apparatus, it is usually required to provide these optical members separately from one or both of the liquid crystal panel and the light source. In addition, these optical members are required to be fixed so as not to deviate from the sandwiching position so that the optical sheet does not undergo deformation such as wrinkles or deflection in the apparatus after manufacture. It is known that fixing of such an optical member in the apparatus can be achieved, for example, by holding the optical member with a predetermined support member (Patent Document 1).

JP 2001-210128 A

  The stretched film is one of the constituent members of the optical sheet. This stretched film generally has low rigidity, and since it is difficult to maintain the shape of the stretched film itself, sagging tends to occur. Further, when a stress is applied to the stretched film after production for some reason, the stretched film is easily shrunk due to the relaxation of the stress. For this reason, when the optical sheet has a stretched film, it is difficult to suppress deformation such as wrinkles and sagging generated in the optical sheet with the conventional technique described in Patent Document 1. .

  Accordingly, an object of the present invention is to provide an optical member that suppresses deformation of an optical sheet having a stretched film and has improved reliability for maintaining the shape of the optical sheet, and a liquid crystal display device including the optical member.

As a result of investigations to solve the above problems, the present inventors have prepared an optical member in which an optical sheet having a stretched film is sandwiched between a porous light diffuser and a substrate so that a predetermined stress is applied to the edge of the optical sheet. Thus, the present inventors have found that the problem can be solved by sandwiching the optical member and mounting the optical member on the liquid crystal display device, and completed the present invention.
That is, according to the present invention, the following [1] to [11] are provided.

[1] A porous light diffuser that is an optical member that is sandwiched and attached to the support member of a liquid crystal display device that includes a light source and a pair of support members, and has pores on at least a surface far from the light source And an optical sheet having a stretched film and a substrate in this order from the light source side, and when the optical member is mounted on the liquid crystal display device, the stress applied to the edge of the optical sheet is 0.2 MPa. This is the optical member.
[2] The optical member according to [1], wherein the porosity of the surface having the pores of the porous light diffuser is 5 to 70%.
[3] The optical member according to [1] or [2], wherein the porous light diffuser contains translucent particles therein.
[4] The optical member according to any one of [1] to [3], wherein the thickness of the substrate is 0.1 mm to 5.0 mm.
[5] The optical member according to any one of [1] to [4], wherein the optical sheet has a reflective polarizer.
[6] The optical member according to any one of [1] to [5], wherein the optical sheet includes a light diffusion sheet.
[7] The optical member according to any one of [1] to [6], in which the optical sheet has a condensing sheet.
[8] The optical member according to any one of [1] to [7], wherein the substrate is a liquid crystal panel.
[9] The optical member according to any one of [1] to [8], comprising a double-sided uneven sheet having translucent particles protruding on both sides between the optical sheet and the substrate.
[10] The optical sheet according to any one of [1] to [9], wherein an edge of the optical sheet is inside an outer edge of a portion sandwiched between the porous light diffuser and the support member of the substrate. Optical member.
[11] A liquid crystal display device comprising the optical member according to any one of [1] to [10].

The optical member of this invention can suppress the deformation | transformation of the optical sheet which has a stretched film, and can improve the reliability regarding the shape maintenance of an optical sheet.
Since the liquid crystal display device of the present invention includes the optical member of the present invention having high reliability for shape retention, the image quality is good.

FIG. 1 is a longitudinal sectional view schematically showing a part of the first embodiment of the liquid crystal display device of the present invention, which includes the optical member of the present invention. FIG. 2 is a longitudinal sectional view schematically showing a part of the first embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention, and enlarges the vicinity of the edge of the optical sheet of FIG. FIG. FIG. 3 is a top view schematically showing an example of the positional relationship between the support member and other components in the liquid crystal display device shown in FIG. FIG. 4 is a top view schematically showing an example of the positional relationship between the support member and other components in the liquid crystal display device shown in FIG. FIG. 5 is a top view schematically showing an example of the positional relationship between the support member and other components in the liquid crystal display device shown in FIG. FIG. 6 is a top view schematically showing an example of the positional relationship between the support member and other components in the liquid crystal display device shown in FIG. FIG. 7 is a longitudinal sectional view schematically showing a part of a second embodiment of the liquid crystal display device of the present invention, which includes the optical member of the present invention. FIG. 8 is a longitudinal sectional view schematically showing a part of the second embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention, and enlarges the vicinity of the edge of the optical sheet of FIG. FIG. FIG. 9 is a longitudinal sectional view schematically showing a part of a third embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention. FIG. 10 is a longitudinal sectional view schematically showing a part of a fourth embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view schematically showing a part of the first embodiment of the liquid crystal display device of the present invention, which includes the optical member of the present invention. In the present specification, unless otherwise specified, the “up” and “down” directions refer to an optical member or a liquid crystal display device in a state where the light emission surface or the display surface is placed horizontally upward. It means “up” and “down” directions, which coincide with the up and down directions in the drawing of FIG. 1 which is a longitudinal sectional view.

  As shown in FIG. 1, the liquid crystal display device 1 includes a linear light source 2 as a light source and a backlight housing 3 that supports the linear light source 2. The backlight housing 3 includes a bottom plate portion 3B, a side plate portion 3S provided around the bottom plate portion 3B and supporting the linear light source 2, and a peripheral portion 3F further provided around the side plate portion 3S and supporting the optical member 4. And have.

  The liquid crystal display device 1 further includes an optical member 4 on the peripheral portion 3F. In the present embodiment, the optical member 4 includes at least a porous light diffuser 41, an optical sheet 42 having a stretched film, and a substrate 43 in this order from the linear light source 2 side. The optical member 4 is mounted on the liquid crystal display device 1 by sandwiching an edge 4e of the optical member 4 between the peripheral portion 3F and a support member 5 described later. That is, the backlight housing 3 and the support member 5 form a pair of support members that support the optical member 4, and the optical member 4 is sandwiched between the peripheral portion 3 </ b> F of the backlight housing 3 and the support member 5 with a constant force. Thus, the optical member 4 is held.

The liquid crystal display device 1 further includes a frame member 7 fastened to the peripheral portion 3F of the backlight housing 3 via bolts 6. The bolt 6 passes through a bolt hole 7H provided in the frame member 7 and a bolt hole 3H provided in the peripheral portion 3F of the backlight housing 3, and is screwed with a screwing member (not shown) such as an appropriate nut. By doing so, the peripheral part 3F and the frame member 7 are fastened. Alternatively, the bolt hole 3H may be used as a screw hole screwed with the bolt 6, and fastening may be performed by screwing the bolt 6 into the screw hole.
The frame member 7 is also supported by a lower frame member 8, which is an optional component, provided below the bottom plate portion 3 </ b> B of the backlight housing 3. The lower frame member 8 can be provided for securing the mechanical strength of the apparatus, and for accommodating optional components such as light shielding and wiring.

  On the surface 7L of the frame member 7 facing the optical member 4, a support member 5 is provided so as to protrude toward the peripheral portion 3F of the backlight housing 3. In the present embodiment, the support member 5 is manufactured as a member separate from the frame member 7, and the upper surface 5U thereof faces the surface 7L of the frame member, and these surfaces are optional adhesive layers (not shown). It is assumed that both members are fastened through a fastening member (not shown) such as an arbitrary screw in a state where these surfaces are in contact with each other. However, the present invention is not limited to this, and the frame member 7 and the support member 5 can be formed integrally with a common material, whereby the frame member 7 can be provided with the support member 5.

  The frame member 7 has an opening 7A on the inner side (left side of the frame member 7 in FIG. 1), and this opening 7A normally prevents the amount of light at the periphery of the opening 7A from being significantly lower than the central portion. The backlight housing 3 is disposed inside the opening 3A. The liquid crystal panel 9 is fixed to the opening 7A of the frame member 7 directly or via another member. For example, the liquid crystal panel 9 is fixed by being attached to the frame member 7 or fastened by an appropriate member. Thereby, the liquid crystal display device 1 including the optical member 4 is configured.

In the present embodiment, in the state where the optical member 4 is mounted on the liquid crystal display device 1, the edge 42 </ b> E of the optical sheet 42 is generated by a force that sandwiches the optical member 4 between the backlight housing 3 and the support member 5 that are support members. The strength of the stress applied to is 0.2 MPa or more, preferably 0.3 MPa or more. Since the optical sheet 42 having the stretched film has low rigidity, conventionally, when the optical sheet is sandwiched between the support members, deformation such as bending is likely to occur. However, in this embodiment, the optical sheet 42 is porous light as shown in FIG. Since it is sandwiched between the diffuser 41 and the substrate 43, the above-described deflection can be suppressed. The upper limit of the strength of the stress applied to the edge 42E of the optical sheet 42 is not uniform because it depends on the dimensions of the liquid crystal display device 1 and the required image quality, but is usually 1.5 MPa or less, preferably 1 .25 MPa or less.
The magnitude of the stress applied to the edge 42E of the optical sheet 42 is a pressure measurement film (for example, pressure measurement manufactured by Fuji Photo Film Co., Ltd.) between the optical sheet 42 and the substrate 43 in an environment of a temperature of 22 ° C. and a humidity of 58% RH. A film (product name: Fuji Prescale)) is spread about 50 mm larger than the outer dimension of the optical sheet 42, the liquid crystal display device 1 is assembled, disassembled, and the discoloration degree of the prescale is compared with the continuous pressure standard chart. it can.

  Furthermore, in this embodiment, the porous light diffuser 41 has pores on at least the surface 41 </ b> S on the side far from the linear light source 2. For this reason, shrinkage | contraction in a stretched film etc. can be eased and generation | occurrence | production of a wrinkle can be suppressed. That is, as shown in FIG. 1, the porous light diffuser 41 is in contact with the optical sheet 42 on the surface 41 </ b> S, but the surface 41 </ b> S has a small contact area with the optical sheet 42 because holes are formed. For this reason, the slipperiness of the optical sheet 42 on the surface 41S of the porous light diffuser 41 is improved. Therefore, when the stress of the optical sheet 42 is reduced due to the installation environment of the liquid crystal display device 1 and the optical sheet 42 tries to shrink, the porous light diffuser 41 does not prevent the shrinkage. , It is possible to suppress the deformation from locally occurring in the optical sheet 42 and to suppress the occurrence of wrinkles.

FIG. 2 is a longitudinal sectional view schematically showing a part of the first embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention, and shows the vicinity of the edge 42E of the optical sheet 42 of FIG. FIG. In FIG. 2, the linear light source 2, the bolt 6, the frame member 7, the lower frame member 8, and the liquid crystal panel 9 are indicated by broken lines.
As shown in FIG. 2, the edge 42E of the optical sheet 42 is the outer edge of the portions 41P and 43P of the porous light diffuser 41 and the substrate 43 that are sandwiched between the support members (ie, the backlight housing 3 and the support member 5). It is preferable to be inside (left side in the figure) of 41P _out and 43P _out . Thereby, the pressure applied to the edge 42E of the optical sheet 42 can be made uniform, and the deformation of the optical sheet 42 can be suppressed more stably. The edge 42E of the optical sheet 42 is preferably inside the at least one of the outer edges 41P _out and 43P _out of the sandwiched portions 41P and 43P, but more preferably inside the both.
Here, the porous light diffuser 41 and the peripheral portion 3F of the backlight housing 3 are in contact with the portion 41P sandwiched by the support member of the porous light diffuser 41 (backlight housing 3 in this embodiment). The part to do. On the other hand, the portion 43P sandwiched between the support members 5 of the substrate 43 refers to a portion where the substrate 43 and the support member 5 are in contact with each other. From the viewpoint of stably obtaining the above-described effect of more stably suppressing the deformation of the optical sheet 42, the edge 42E of the optical sheet 42 is inside the outer edge 41P _{out of the} portion 41P and the inner edge 41P _{in of the} portion 41P. It is preferable that it exists outside. On the other hand, from the same viewpoint, the edge 42E of the optical sheet 42 is preferably inside the outer edge 43P _{out of} the portion 43P, and more preferably inside the inner edge 43P _{in of the} portion 43P.
However, if the edge 42 </ b> E of the optical sheet 42 covers the opening 7 </ b> A of the frame member 7, brightness unevenness may occur on the display surface of the liquid crystal display device 1, so the edge 42 </ b> E of the optical sheet 42 is more than the inner edge 7 </ b> E of the frame member 7. Is preferably outside.

  FIG. 3 is a top view schematically showing an example of the positional relationship between the support member 5 and other components in the liquid crystal display device 1 shown in FIG. 3, for the sake of illustration, only the support member 5, the optical member 4, the peripheral portion 3F of the backlight housing 3 (see FIG. 1), and the linear light source 2 are shown.

In FIG. 3, the optical member 4 is placed on the peripheral portion 3F so as to cover the entire opening (shown by a broken line 3A in the figure) defined by the peripheral portion 3F of the backlight housing 3, thereby The optical member 4 filters all the light that is reflected from the linear light source 2 directly or from the inner surface of the backlight housing 3 and then emitted to the opening 3A.
In FIG. 3, the optical member 4 has a rectangular plate shape having four sides 4A to 4D. In each of these four sides 4A to 4D, a support member is provided in a region inside the sides 4A to 4D and outside the opening 3A. 5 is arranged.

  Since the liquid crystal display device 1 of the present embodiment is configured as described above, the light emitted from the linear light source 2 by turning on the linear light source 2 is reflected directly or after being reflected by the backlight housing 3. , Enters the optical member 4 from below. The light incident on the optical member 4 is diffused in the process of passing through the porous light diffuser 41, and in the process of passing through the optical sheet 42, the light is diffused, condensed, converted into polarized light, etc. depending on the type of the optical sheet 42. Under the action, only the polarized light used by the liquid crystal panel 9 (see FIG. 1) is evenly and efficiently emitted to the liquid crystal panel 9. Then, the light emitted from the optical member 4 enters the liquid crystal panel 9 and is used as light for display of the liquid crystal display device 1 to display an image or the like. In particular, in the liquid crystal display device 1 according to the present embodiment, the optical member 4 suppresses deformation of the optical sheet 42 and increases the reliability related to the shape retention of the optical sheet 42. Can be good.

By the way, the optical member 4 and the liquid crystal display device 1 as the first embodiment of the present invention described above may be further modified.
For example, in the example shown in FIG. 3, the support member 5 is provided so as to correspond to all of the four sides 4 </ b> A to 4 </ b> D of the optical member 4, but in order to obtain advantages such as simplification and weight reduction of the device, The supporting member 5 may be provided corresponding to only a part of the side of the rectangular optical member 4 having 4D. However, it is preferable to have the supporting members 5 corresponding to at least two opposite sides among the four sides 4A to 4D. Furthermore, in this case, having the supporting members 5 corresponding to at least the long-side pair among the long-side pair and the short-side pair effectively prevents the occurrence of problems such as breakage, warpage and displacement of the optical member 4. It is preferable from the viewpoint of prevention.
For example, as shown in FIG. 4, the corresponding support member 5 can be provided only on the long sides 4A and 4B facing each other among the four sides 4A to 4D. Alternatively, as shown in FIG. 5, in addition to the support member 5 corresponding to the sides 4A and 4B, a support member 5 corresponding to the side 4C which is one of the short sides 4C and 4D may be provided.
In the example shown in FIG. 3, the support member 5 has a structure in which the integral member covers the entire four sides 4 </ b> A to 4 </ b> D, but from the viewpoint of ease of manufacture, the members corresponding to the four sides 4 </ b> A to 4 </ b> D respectively. May be divided into two or more members. For example, as shown in FIG. 6, support members 5 corresponding to the sides 4 </ b> A to 4 </ b> D may be provided independently. When providing independently, it is preferable to make the clearance gap of the boundary part of each member as small as possible.

In the example of FIG. 1, the shape of the cross section perpendicular to the longitudinal direction of the support member 5 at each side has a rectangular shape as illustrated in FIG. 1, but the support member in the liquid crystal display device of the present invention has a rectangular shape. The shape is not limited to this, and can take various shapes.
Furthermore, at least one pair of the backlight housing 3 and the support member 5 that are support members that sandwich the optical member 4 may be provided in the liquid crystal display device 1, and for example, two or more pairs may be provided.

  Further, the liquid crystal display device 1 may further include an arbitrary member as long as the effects of the present invention are not significantly impaired. For example, a light diffusion sheet may be provided between the linear light source 2 and the optical member 4 in order to more surely suppress uneven brightness. For example, a heat insulating film may be provided between the optical member 4 and the liquid crystal panel 9 in order to suppress heat transfer from the linear light source 2 to the liquid crystal panel 9.

[Second Embodiment]
In the optical member and the liquid crystal display device of the present invention, a liquid crystal panel may be used as the substrate of the optical member as in the second embodiment described below.

FIG. 7 is a longitudinal sectional view schematically showing a part of a second embodiment of the liquid crystal display device of the present invention, which includes the optical member of the present invention. In this embodiment as well, as in the first embodiment, the “up” and “down” directions coincide with the up and down directions in the drawing of FIG. 7 which is a longitudinal sectional view.
As shown in FIG. 7, the liquid crystal display device 101 of the present embodiment includes a liquid crystal panel 9 as a substrate constituting the optical member 104, and includes a peripheral portion 3 </ b> F of the backlight housing 3 and a ceiling portion 7 </ b> C of the frame member 7. The optical member 104 is mounted on the liquid crystal display device 101 by sandwiching the edge portion 104e of the optical member 104 therebetween, and the liquid crystal display device 1 of the first embodiment is not provided with the support member 5 and the bolt 6 not provided. It is the same.

  That is, the liquid crystal display device 101 includes the linear light source 2, the backlight housing 3, the frame member 7, and the lower frame member 8 similar to the liquid crystal display device 1 of the first embodiment, and the optical member 4 and the liquid crystal panel 9. Instead of this, an optical member 104 is provided. The optical member 104 includes at least a porous light diffuser 41, an optical sheet 42 having a stretched film, and a liquid crystal panel 9 as a substrate in this order from the linear light source 2 side. The backlight housing 3 and the frame member 7 serve as a pair of support members that support the optical member 104, and the peripheral portion 3F of the backlight housing 3 and the ceiling portion 7C of the frame member 7 are the edges of the optical member 104. The optical member 104 is held by sandwiching 104e with a constant force.

Further, in the present embodiment, the strength of the stress applied to the edge 42E of the optical sheet 42 in the state where the optical member 104 is mounted on the liquid crystal display device 101 is in the same range for the same reason as in the first embodiment.
Also in this embodiment, the porous light diffuser 41 has pores on at least the surface 41S on the side far from the linear light source 2 in the same manner as in the first embodiment, and alleviates shrinkage in a stretched film or the like. Deformation due to the generation of wrinkles can be suppressed. In order to suppress the deformation more stably, as shown in FIG. 8, the edge 42E of the optical sheet 42 is supported by the porous light diffuser 41 and the liquid crystal panel 9 (ie, the backlight housing 3 and the frame member). 7) The portions 41P and 9P sandwiched by 7) are preferably located on the inner side (left side in the drawing) of the outer edges 41P _out and 9P _{out, and} more preferably located on the outer side of the inner edge 41P _{in of the} portion 41P. This is the same as the embodiment. However, in the present embodiment, the inner edge 7E of the frame member 7 and the inner edge 9P _{in of the} portion 9P where the liquid crystal panel 9 is sandwiched by the frame member 7 coincide. Accordingly, since the edge 42E of the optical sheet 42 is likely to cause it takes luminance unevenness in the opening 7A of the frame member 7, the edge 42E of the optical sheet 42 on the inside than the inner edge 9P _in is preferably avoided.
FIG. 8 is a longitudinal sectional view schematically showing a part of the second embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention, and shows an edge 42E of the optical sheet 42 of FIG. It is a figure which expands and shows the vicinity. In FIG. 8, the linear light source 2 and the lower frame member 8 are indicated by broken lines.

Since the liquid crystal display device 101 of the present embodiment is configured as described above, the light emitted from the linear light source 2 is diffused in the process of passing through the porous light diffuser 41 and transmitted through the optical sheet 42. The liquid crystal panel 9 receives the action of diffusion, condensing, conversion to polarized light, etc. according to the type of the optical sheet 42, enters the liquid crystal panel 9, and is used as light for display of the liquid crystal display device 101 to display an image or the like. The Also in this embodiment, the same advantages as those in the first embodiment such as suppression of deformation of the optical sheet 42 and improvement in image quality can be obtained.
Furthermore, in this embodiment, since the liquid crystal panel 9 is used as a substrate constituting the optical member 104, advantages such as reduction in the number of components, simplification of the assembly process, space saving, and weight reduction can be obtained.

However, since the liquid crystal panel 9 is used as a substrate in the present embodiment, the distance between the linear light source 2 and the liquid crystal panel 9 is shorter than that in the first embodiment. For this reason, from the viewpoint of suppressing the transfer of heat from the linear light source 2 to the liquid crystal panel 9, in the liquid crystal display device 101 of the present embodiment, the distance between the linear light source 2 and the optical member 104 is set to the liquid crystal of the first embodiment. It is preferable that it is wider than the display device 1.
In the present embodiment, the optical member 104 and the liquid crystal display device 101 may be further modified as in the first embodiment.

[Third Embodiment]
In the optical member and the liquid crystal display device of the present invention, the optical member may include components other than the porous light diffuser, the optical sheet, and the substrate. However, from the viewpoint of stably suppressing the deformation of the optical sheet, the porous light diffuser and the optical sheet are preferably in direct contact with each other. For example, as in the third embodiment described below, the optical member may be provided with a double-sided uneven sheet in which translucent particles protrude on both sides between the optical sheet and the substrate.

FIG. 9 is a longitudinal sectional view schematically showing a part of a third embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention. In the present embodiment, as in the first embodiment, the “up” and “down” directions coincide with the up and down directions in the drawing of FIG. 9 which is a longitudinal sectional view.
As shown in FIG. 9, the liquid crystal display device 201 of the present embodiment is the same as the liquid crystal display device of the first embodiment except that the optical member 204 includes a double-sided uneven sheet 44 between the optical sheet 42 and the substrate 43. Same as 1.

  That is, the liquid crystal display device 201 includes the same linear light source 2, backlight housing 3, support member 5, bolt 6, frame member 7, lower frame member 8, and liquid crystal panel as the liquid crystal display device 1 of the first embodiment. 9 and an optical member 204 instead of the optical member 4. The optical member 204 includes, from the linear light source 2 side, at least a porous light diffuser 41, an optical sheet 42 having a stretched film, a double-sided uneven sheet 44 having translucent particles protruding on both sides, and a substrate 43. Are provided in this order.

Since the liquid crystal display device 201 of the present embodiment is configured as described above, it operates in the same manner as the liquid crystal display device 1 of the first embodiment and can obtain the same advantages. Furthermore, since the optical member 204 of the present embodiment includes the double-sided uneven sheet 44 between the optical sheet 42 and the substrate 43, the optical contact between the optical sheet 42 and the substrate 43 is prevented, and light interference occurs. Can be suppressed. Further, the light incident on the double-sided uneven sheet 44 can be diffused or condensed depending on the particle size, shape, distribution density, and the like of the translucent particles of the double-sided uneven sheet 44.
In the present embodiment, the optical member 204 and the liquid crystal display device 201 may be further modified as in the first embodiment.

[Fourth Embodiment]
In the optical member and the liquid crystal display device of the present invention, for example, as in the fourth embodiment described below, even when a liquid crystal panel is used as the substrate of the optical member, the optical member is an optical sheet and a substrate. In between, you may make it provide the double-sided uneven | corrugated sheet which made the translucent particle | grains protrude on both surfaces.

FIG. 10 is a longitudinal sectional view schematically showing a part of a fourth embodiment of the liquid crystal display device of the present invention provided with the optical member of the present invention. In this embodiment as well, as in the first embodiment, the “up” and “down” directions coincide with the up and down directions in the longitudinal sectional view of FIG.
As shown in FIG. 10, the liquid crystal display device 301 of the present embodiment is the second embodiment except that the optical member 304 includes a double-sided uneven sheet 44 between the optical sheet 42 and the liquid crystal panel 9 as a substrate. This is the same as the liquid crystal display device 101 of FIG.

  That is, the liquid crystal display device 301 includes the linear light source 2, the backlight housing 3, the frame member 7, and the lower frame member 8 similar to those of the liquid crystal display device 101 of the second embodiment, and optical instead of the optical member 104. A member 304 is provided. The optical member 304 includes at least a porous light diffuser 41, an optical sheet 42 having a stretched film, a double-sided uneven sheet 44 having translucent particles protruding on both sides, and a substrate from the linear light source 2 side. A certain liquid crystal panel 9 is provided in this order.

Since the liquid crystal display device 301 of the present embodiment is configured as described above, it operates in the same manner as the liquid crystal display device 101 of the second embodiment and can obtain the same advantages. Furthermore, since the optical member 304 of the present embodiment includes the double-sided uneven sheet 44 between the optical sheet 42 and the liquid crystal panel 9 as a substrate, optical adhesion between the optical sheet 42 and the liquid crystal panel 9 is prevented, and light Occurrence of interference can be suppressed. Further, the light incident on the double-sided uneven sheet 44 can be diffused or condensed depending on the particle size, shape, distribution density, and the like of the translucent particles of the double-sided uneven sheet 44.
In the present embodiment, the optical member 304 and the liquid crystal display device 301 may be further modified as in the first embodiment.

[Each component]
Subsequently, examples of each component included in the optical member and the liquid crystal display device of the present invention will be sequentially described.

(1. Light source and light source support)
As said light source, linear light sources, such as a cold cathode tube and a hot cathode tube, point light sources, such as a light emitting diode (LED), etc. can be used.

  The light source support supports the light source in the liquid crystal display device, has an opening for emitting light from the light source, and further has a peripheral portion extending around the opening. The light source support is a backlight housing that usually has a housing shape, has a reflection plate inside, and has an opening on the top surface. In general, as in the first to fourth embodiments described above, the light source support also functions as an optical member support that supports the optical member.

  The arrangement of the light sources defined by the light source support is not particularly limited. For example, when linear light sources are arranged in a backlight housing, the linear light sources are parallel to each other and to the inner bottom surface of the housing. It is preferable to arrange them at a predetermined distance from the inner bottom surface. The backlight housing does not necessarily have a rectangular parallelepiped shape. For example, the extension direction of the side surface may be inclined from a direction perpendicular to the bottom surface, and light from the light source is formed on the inner bottom surface of the housing. May be unevenly arranged in the middle of the linear light source.

(2. Optical member)
The optical member includes at least a porous light diffuser, an optical sheet, and a substrate in this order. The optical member preferably includes a double-sided uneven sheet between the optical sheet and the substrate.

(2.1. Porous light diffuser)
The porous light diffuser is a plate-like or sheet-like member having pores on at least one of the front surface and the back surface. In the optical member, in the porous light diffuser, the surface on the side having pores is the surface on the side far from the light source (that is, the side facing the optical sheet). Here, the porous light diffuser may have pores on at least the surface on the side far from the light source, but may further have pores on the inside and on the surface near the light source. From the viewpoint of increasing the rigidity of the porous light diffuser, the porous light diffuser preferably has pores only on the surface farther from the light source. Also, from the viewpoint of reducing the weight of the porous light diffuser, enhancing the light diffusion function, and improving the reliability by preventing the bias of the temperature distribution of the porous light diffuser, the surface on the inside and the side closer to the light source It is preferable to have pores.

The porosity of the surface having pores of the porous light diffuser is preferably 5% or more, more preferably 10% or more, and particularly preferably 30% or more. With such a high hole occupation ratio, sticking between the porous light diffuser and the optical sheet can be suppressed to prevent optical adhesion. In addition, even if the porous light diffuser and the optical sheet are attached, the optical characteristics of the optical member are not drastically deteriorated because there are sufficiently many holes, and the image quality of the liquid crystal display device is reduced. Reduction can be suppressed. However, since the rigidity of the porous light diffuser may be too low when the vacancy occupancy is too high, the vacancy occupancy is preferably 70% or less, more preferably 65% or less, and 55%. The following are particularly preferred:
In addition, a hole occupation rate means the ratio of the area of the part in which the hole which occupies for the surface which has a hole was formed. The hole occupancy ratio is obtained by observing the porous light diffuser 41 in a field of a predetermined area from the normal direction of the main surface, obtaining the sum of the areas of all the holes in the observation field, The hole occupancy ratio in this example can be obtained by obtaining a value of (hole area / observation visual field area) × 100, and obtaining this value in a plurality of observation visual fields in the concavo-convex area as necessary to obtain an average.

The mode value of the pore diameter of the porous light diffuser is usually 0.5 μm or more, preferably 1.0 μm or more, more preferably 2.0 μm or more, and usually 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less. When the mode of the pore diameter of the porous light diffuser is within the above range, the local deformation of the optical sheet is suppressed by improving the slipperiness between the porous light diffuser and the optical sheet. It is possible to suppress luminance unevenness, improve luminance by light collection effect utilizing light recycling, and suppress luminance unevenness.
The mode value of the pore diameter of the porous light diffuser can be measured using a digital microscope, an ultradeep microscope, a reflection electron microscope, an atomic force microscope, or the like.

The load length ratio Rmr (c) of the porous light diffuser is usually 30% or more, preferably 35% or more, more preferably 40% or more, and usually 90% or less at a cutting level height of 50%. , Preferably 85% or less, more preferably 80% or less.
The load length ratio Rmr (c) can be measured using an ultradeep microscope in accordance with JIS B0601-2001.

A porous light diffuser that transmits light emitted from a light source is used. Although the specific light transmittance is not uniform depending on the luminance required for the liquid crystal display device, the total light transmittance of the porous light diffuser is usually 60% or more, preferably 65% or more, more preferably 70% or more. To be. The total light transmittance of the porous light diffuser is ideally 100%, but is usually 98% or less, and is actually 95% or less in view of cost and the like.
The total light transmittance is a value measured based on JIS K7361-1.

The porous light diffuser has a property of diffusing incident light. Although the specific degree of diffusion is not uniform depending on the degree of image quality required for the liquid crystal display device, the haze of the porous light diffuser is preferably 30% to 90%.
The haze is a value measured according to JIS K7136.

Since the porous light diffuser is a member that is paired with the substrate and supports the optical sheet so that the optical sheet does not deform, it is preferable that the optical sheet has rigidity to the extent that deformation such as bending does not occur. Further, the porous light diffuser may be a combination of a low-rigidity member having porosity on the surface and a high-rigidity plate. The combination includes, for example, a laminate; a laminate bonded through an adhesive layer or an adhesive layer; a bond fixed using thermal fusion, ultrasonic fusion, laser welding, or the like.
The specific strength of the porous light diffuser may be set according to the shape, size, weight, etc. of the optical member. However, since the optical sheet may bend when the porous light diffuser is bent, it is preferable that the bending rigidity of the porous light diffuser is high. Specifically, the bending stiffness of a porous light diffuser having a length of 60 mm and a width of 25 mm is preferably ² mN · m ² or more, more preferably 20 mN · m ² or more, and particularly preferably 50 mN · m ² or more. The upper limit is not limited, but in reality, it is 300 mN · m ² or less.
Moreover, the thickness of the porous light diffuser is usually 100 μm to 5 mm.

As a material for the porous light diffuser, an inorganic material such as glass may be used, but an organic material such as a resin is usually used. For example, polyethylene, propylene-ethylene copolymer, polypropylene, polystyrene, polyvinyl chloride, polyurethane, a copolymer of an aromatic vinyl monomer and a (meth) acrylic acid alkyl ester having a lower alkyl group, polyethylene Terephthalate, terephthalic acid-ethylene glycol-cyclohexanedimethanol copolymer, polycarbonate, acrylic resin, resin having alicyclic structure, biodegradable polymer (eg, polybutadiene, polylactic acid, polyhydroxybutyric acid, polycaprolactone, etc.), polyimide Examples thereof include resins and melamine resins. In addition, (meth) acrylic acid represents acrylic acid and methacrylic acid. Moreover, only 1 type may be used for the material of a porous light diffuser, and it may use it combining 2 or more types by arbitrary ratios.
Among these, a copolymer with (meth) acrylic acid alkyl ester, polypropylene, polystyrene, and a resin having an alicyclic structure are preferable.

  Further, the porous light diffuser may contain an additive such as a light diffusing agent. Especially, it is preferable to contain translucent particles as a light diffusing agent in the porous light diffuser. Although the light diffusion by the porous light diffuser may not be sufficient with the pores alone, the light of the porous light scatterer can be obtained by including a light diffusing agent such as translucent particles inside the porous light diffuser. It is possible to increase the diffusibility and suppress the occurrence of uneven brightness in the image display device more stably.

  The shape of the translucent particles can be, for example, a sphere, a shape made of a curved surface approximated to a sphere, a shape made of a polyhedron, a curved surface, and a flat surface. Examples of the shape made of a curved surface that approximates a sphere include an elliptic sphere. Polyhedrons include prisms, pyramids, and other polyhedrons (for example, regular octahedrons, regular dodecahedrons, regular icosahedrons, etc., regular polyhedrons such as truncated icosahedrons, and shapes close to these). Can be mentioned. In addition, examples of the shape composed of a curved surface and a flat surface include shapes such as a cone, an elliptical cone, a cylinder, and an elliptic cylinder. Among these, the spherical shape is preferable in that the light diffusion direction can be made uniform.

  Examples of the material of the translucent particles include acrylic resin, polyurethane, polyvinyl chloride, polystyrene resin, polyacrylonitrile, polyamide, polysiloxane resin, melamine resin, benzoguanamine resin, and the like as organic materials. Examples of the inorganic material include silica, aluminum oxide, titanium oxide, zinc oxide, barium sulfate, magnesium silicate and the like. In addition, only 1 type may be used for the material of translucent particle | grains, and it may use it combining 2 or more types by arbitrary ratios.

The dimension of the translucent particles is preferably in the range of 0.5 to 10 μm as an average particle diameter from the viewpoint of obtaining desired light diffusibility. Here, the average particle diameter is a number average particle diameter calculated by dispersing translucent particles in distilled water at 3 weight percent, measuring the particle size distribution on a volume basis by a laser diffraction scattering method.
The content ratio of the translucent particles in the porous light diffuser can be appropriately selected according to the thickness of the porous light diffuser, the size of the light source, etc., but the total light transmittance of the porous light diffuser is usually 60. % Or more, preferably 62% or more, more preferably 75% or more, and it is usually adjusted to 98% or less, preferably 95% or less, more preferably 92% or less.

There is no limitation on the method for producing the porous light diffuser, and any known method can be adopted. Examples of the production method include the following methods.
(I) A homogeneous solution of the thermoplastic polymer and diluent is cooled and subjected to liquid-liquid phase separation in a thermodynamic non-equilibrium state, the diluent is removed from the thermoplastic polymer, and subjected to appropriate stretching treatment to obtain a porous material. A method for producing a porous light diffuser as a porous medium (see US Pat. No. 4,867,881).
(Ii) A method for producing a porous light diffuser as a film having pores on the surface by stretching the cast polymer film with a solvent remaining of about 15% by weight to remove the residual solvent (US) (See Japanese Patent No. 6177153).
(Iii) After applying a composition comprising a binder resin, a photosensitive compound and a photopolymerization initiator on a substrate sheet and covering it with a photomask having a desired pattern, electromagnetic wave irradiation is performed, A method for producing a porous light diffuser by infiltrating a poor solvent for the binder resin, and then volatilizing the poor solvent that has penetrated the inside of the binder resin to make either irradiated or non-irradiated portions porous (Japanese Patent Application Laid-Open No. 2004-124). 272153).
(Iv) A mixture containing a crystalline thermoplastic polymer is heated to a melting temperature or higher, melted and mixed, and further cooled to crystallize and aggregate the crystalline thermoplastic polymer to cause phase separation. A method for producing a porous light diffuser as a connected porous body by orienting a phase-separated mixture in one direction (see US Pat. No. 4,539,256).
(V) A mixture in which a nucleating agent is mixed with a crystalline thermoplastic polymer is heated to a melting temperature or higher, melted and mixed, and cooled to increase the degree of crystallinity around the nucleating agent to cause aggregation and phase separation. A method of producing a porous light diffuser as a connected porous body by stretching the phase-separated mixture in one direction (see US Pat. No. 4,726,989).
(Vi) Porous light diffuser having a honeycomb structure by dissolving a polymer in a hydrophobic organic solvent, solution casting under high humidity, condensing on the cast film surface, and evaporating minute water droplets generated by the dew condensation (Refer to JP 2001-157574 A).

(2.2. Optical sheet)
The optical sheet is a sheet having at least one layer of stretched film. Here, the stretched film refers to a film produced through a stretching process in the production process. One of the advantages of the present invention is that a stretched film generally has a low rigidity and can solve the problems caused by the low rigidity.
As long as it has at least one stretched film, the optical sheet may contain optical elements other than the stretched film. Further, the stretched film may have two or more layers.
As an example of the optical element which comprises an optical sheet, a reflective polarizer, a light-diffusion sheet, a condensing sheet, a wavelength plate etc. are mentioned, for example. Any of these optical elements may or may not correspond to a stretched film, but in the optical sheet according to the present invention, at least any one layer may be an optical element manufactured through a stretching process.

(2.2.1. Reflective polarizer)
The reflective polarizer is an optical element having a property of transmitting a part of the polarized light incident thereon and reflecting at least a part of the remaining polarized light. The reflective polarizer includes a circularly polarized light separating element that transmits certain circularly polarized light and reflects the remaining light, and a linearly polarized light separating element that transmits certain linearly polarized light and reflects the remaining light.

(Circularly polarized light separating element: cholesteric resin layer)
A typical circularly polarized light separating element includes a cholesteric resin layer. The cholesteric resin layer is a layer having cholesteric regularity, which is obtained by providing a coating film of a cholesteric liquid crystal composition on a substrate for forming a resin layer and curing the coating film.
Cholesteric regularity means that the molecular axes are aligned in a certain direction on one plane, but the direction of the molecular axis is slightly shifted on the next plane, and the angle is further shifted on the next plane. This is a structure in which the angle of the molecular axis is shifted (twisted) as it advances through a plane in which molecules are arranged in a certain direction. Thus, the structure in which the direction of the molecular axis is twisted becomes an optically chiral structure.

  The optical sheet according to the present invention preferably includes a cholesteric resin layer that exhibits this circularly polarized light separation function over the entire wavelength region of visible light. For example, a cholesteric resin layer having a circularly polarized light separation function is preferable for light in any wavelength region of blue (wavelength 410 to 470 nm), green (wavelength 520 to 580 nm), and red (wavelength 600 to 660 nm).

  The cholesteric resin layer can be obtained, for example, by polymerizing a cholesteric liquid crystal composition (X) containing a polymerizable liquid crystal compound in a curing treatment described later. Such a layer becomes a non-liquid crystalline resin layer cured while exhibiting the molecular orientation of the liquid crystalline compound. Note that the material referred to as a liquid crystal composition here for convenience includes not only a mixture of two or more substances but also a material made of a single substance.

The cholesteric liquid crystal composition (X) contains a compound represented by the following general formula (1) and a specific rod-like liquid crystal compound as a polymerizable liquid crystal compound. Each of these components will be described in turn.
R ^1X -A ^1X -ZA ^2X -R ^2X (1)

In the general formula (1), R ^1X and R ^2X are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched chain having 1 to 20 carbon atoms. And a group selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group. Here, (meth) acryl means acryl and methacryl.

^Further, it is preferred that at least one of ^{R 1X} and ^{R 2X} is a reactive group. By having a reactive group as R ^1X and / or R ^2X , the compound represented by the general formula (1) is fixed in the liquid crystal layer at the time of curing, and a stronger film can be formed. Here, examples of the reactive group include a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group.

In the general formula (1), A ^1X and A ^2X are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4, It represents a group selected from the group consisting of a 4′-bicyclohexylene group and a 2,6-naphthylene group. The 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4,4′-bicyclohexylene group, and 2,6-naphthylene group are , Which may be unsubstituted or substituted with one or more substituents such as a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkyl group having 1 to 10 carbon atoms, and a halogenated alkyl group Good. In each of A ^1X and A ^2X , when two or more substituents are present, they may be the same or different.

Particularly preferable examples of A ^1X and A ^2X include a 1,4-phenylene group, a 4,4′-biphenylene group, and a 2,6-naphthylene group. These aromatic ring skeletons are relatively rigid as compared with the alicyclic skeletons, have high affinity with the mesogens of rod-like liquid crystalline compounds described later, and have higher alignment uniformity.

In the general formula (1), Z represents a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH. = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and is selected from the group consisting of -CH ₂ OCO-. Particularly preferable examples of Z include a single bond, —OCO—, and —CH═N—N═CH—.

  The compound of general formula (1) may or may not have liquid crystallinity. The cholesteric liquid crystal composition (X) preferably contains a mixture of a plurality of optical isomers as the compound of the general formula (1). For example, a mixture of plural kinds of enantiomers and / or diastereomers can be contained. At least one of the compounds of the general formula (1) preferably has a melting point in the range of 50 ° C to 150 ° C.

The cholesteric liquid crystal composition (X) preferably contains a rod-like liquid crystal compound having at least two or more reactive groups in one molecule. Examples of the rod-like liquid crystalline compound include compounds represented by the general formula (2).
R ^3X -C ^3X -D ^3X -C ^5X -MC ^6X -D ^4X -C ^4X -R ^4X Formula (2)

In the general formula (2), R ^3X and R ^4X are reactive groups, each independently (meth) acrylic group, (thio) epoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, vinyl group, It represents a group selected from the group consisting of an allyl group, a fumarate group, a cinnamoyl group, an oxazoline group, a mercapto group, an iso (thio) cyanate group, an amino group, a hydroxyl group, a carboxyl group, and an alkoxysilyl group.
In the general formula (2), D ^3X and D ^4X are a single bond, a divalent saturated hydrocarbon group such as a linear or branched methylene group and alkylene group having 1 to 20 carbon atoms, and a carbon atom. This represents a group selected from the group consisting of several 1 to 20 linear or branched alkylene oxide groups.

In the general formula (2), C ^{3X to} C ^6X are a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH _2. -, - CH = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and represents a group selected from the group consisting of -CH ₂ OCO-.
In the general formula (2), M represents a mesogenic group, specifically, azomethines, azoxys, phenyls, biphenyls, terphenyls, naphthalenes, which may be unsubstituted or substituted. , Anthracenes, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles 2 to 4 skeletons are represented by —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH═N—. N = CH -, - NHCO - , - OCOO -, - CH 2 COO-, and are joined by a linking group of -CH ₂ OCO-, etc. It represents a group to be made.

The rod-like liquid crystalline compound preferably has an asymmetric structure. Here, the asymmetric structure is a structure in which R ^3X -C ^3X -D ^3X -C ^5X -and -C ^6X -D ^4X -C ^4X -R ^4X are different in the general formula (2) with the mesogenic group M as the center. That means. By using a rod-like liquid crystal compound having an asymmetric structure, alignment uniformity can be further improved.

  The rod-like liquid crystal compound may have at least two reactive groups in one molecule. Specific examples of the reactive group include an epoxy group, a thioepoxy group, an oxetane group, a thietanyl group, an aziridinyl group, a pyrrole group, a fumarate group, a cinnamoyl group, an isocyanate group, an isothiocyanate group, an amino group, a hydroxyl group, and a carboxyl group. , Alkoxysilyl group, oxazoline group, mercapto group, vinyl group, allyl group, methacryl group, acrylic group and the like.

  In the cholesteric liquid crystal composition (X), the weight ratio of (total weight of the compound of the general formula (1)) / (total weight of the rod-like liquid crystal compound) is preferably 0.05 to 1. It is more preferably 1 to 0.65, and further preferably 0.15 to 0.45. If the weight ratio is less than 0.05, the alignment uniformity may be insufficient. On the other hand, if it is more than 1, the alignment uniformity is lowered, the stability of the liquid crystal phase is lowered, or Δn as the liquid crystal composition is lowered, so that desired optical performance (for example, circularly polarized light separation characteristics) cannot be obtained. There is a case. The total weight indicates the weight when one kind is used and the total weight when two or more kinds are used.

  The cholesteric liquid crystal composition can optionally contain a chiral agent. As an example of a specific chiral agent, the compounds represented by the following (C1) and (C2) having an isosorbide skeleton in which the chiral group is divalent can be used. Further, as a commercially available chiral agent, for example, LC756 of BASF Corporation Paliocolor can be obtained.

  The chiral agent can be included in a range that does not deteriorate the desired optical performance. The content ratio of the chiral agent is usually 1 to 60% by weight in the cholesteric liquid crystal composition.

  The cholesteric liquid crystal composition can further contain other optional components as necessary. Examples of the other optional components include solvents, photopolymerization initiators, surfactants, crosslinking agents, polymerization inhibitors for improving pot life, antioxidants for improving durability, ultraviolet absorbers, and light stability. And the like. These optional components can be included in a range that does not deteriorate the desired optical performance.

  The manufacturing method of a cholesteric liquid crystal composition is not specifically limited, It can manufacture by mixing said each component.

  As a method for producing a cholesteric resin layer, for example, the cholesteric liquid crystal composition is applied onto a base material layer directly or through an alignment film to obtain a coating film, and then subjected to light irradiation and / or application one or more times. A cholesteric resin layer can be obtained by performing a temperature treatment to cure the coating film. More specifically, the cholesteric resin layer can be produced by the following methods (M1) to (M3).

(M1) As the base material layer, a layer that is another component of the optical member such as a quarter-wave plate can be used, and a cholesteric resin layer can be directly provided thereon. For example, a laminated structure of a quarter wavelength plate and a cholesteric resin layer can be obtained by using a quarter wavelength plate as a base material layer and forming a cholesteric resin layer thereon.
(M2) As the base material layer, a base material layer such as a light-transmitting resin that does not impair the effects of the present invention even if present in the optical member, and a cholesteric resin layer can be formed thereon. Further, each base material layer may be adhered to another layer (for example, a quarter-wave plate) via an adhesive layer or the like, and a cholesteric layer may be provided on the optical member. By carrying out like this, the laminated structure of a quarter wavelength plate and a cholesteric resin layer can be obtained, for example through an adhesion layer.
(M3) An arbitrary base material layer is used as the base material layer, a cholesteric resin layer is formed thereon, and the cholesteric resin layer is formed on another layer (for example, a quarter wavelength plate) via an adhesive layer or the like as necessary. Etc.) and the base material layer may be peeled off to provide a cholesteric layer on the optical member. By carrying out like this, the base material-less laminated structure of a quarter wavelength plate and a cholesteric resin layer can be obtained through an adhesion layer, for example.

  As the substrate layer used in the methods (M2) and (M3), a transparent resin substrate can be preferably used. As the transparent resin substrate, for example, a substrate having a thickness of 1 mm and a total light transmittance of 80% or more can be used. Among these, alicyclic olefin polymers or chain olefin polymers are preferable, and alicyclic olefin polymers are particularly preferable from the viewpoints of transparency, low hygroscopicity, dimensional stability, lightness, and the like.

In any of the methods (M1) to (M3), an alignment film can be provided on the base material layer as necessary. By providing the alignment film, the cholesteric liquid crystal composition applied thereon can be aligned in a desired direction. The alignment film is subjected to corona discharge treatment or the like on the surface of the base material layer, if necessary, and then a solution obtained by dissolving the alignment film material in water or a solvent is used for reverse gravure coating, direct gravure coating, die It can be formed by applying and drying using a known method such as coating or bar coating, and then subjecting the dried coating film to rubbing treatment. The material for the alignment film is preferably a modified polyamide from the viewpoint of durability and the like. On the other hand, polyvinyl alcohol is particularly preferable from the viewpoint of easy transfer in the method (M3).
Examples of the modified polyamide include those obtained by modifying an aromatic polyamide or an aliphatic polyamide, and those obtained by modifying an aliphatic polyamide are preferred.

  Before curing the coating film obtained by the application, an orientation treatment may be performed as necessary. The orientation treatment is performed, for example, by heating the coating film at 50 to 150 ° C. for 0.5 to 10 minutes. By performing the alignment treatment, a substance capable of exhibiting a cholesteric liquid crystal phase in the coating film can be well aligned.

  The curing step is performed by, for example, one or more times of light irradiation, heating treatment, or a combination thereof. The heating conditions are, for example, a temperature of 40 to 200 ° C, preferably 50 to 200 ° C, more preferably 50 to 140 ° C, and a time of 1 second to 3 minutes, preferably 5 to 120 seconds. In addition, the light used for light irradiation includes not only visible light but also ultraviolet rays and other electromagnetic waves. Light irradiation can be performed, for example, by irradiating light having a wavelength of 200 to 500 nm for 0.01 seconds to 3 minutes.

In addition, as a process for broadening the band, for example, a weak ultraviolet irradiation of 0.01 to 50 mJ / cm ² and heating may be alternately repeated a plurality of times to obtain a circularly polarized light separating element having a wide reflection band. After expanding the reflection band by the above-mentioned weak ultraviolet irradiation, etc., a relatively strong ultraviolet ray of 50 to 10,000 mJ / cm ² is irradiated to completely polymerize the liquid crystalline compound to form a cholesteric resin layer. it can. The expansion of the reflection band and the irradiation with strong ultraviolet rays may be performed in the air, or a part or all of the process may be performed in an atmosphere in which the oxygen concentration is controlled (for example, in a nitrogen atmosphere). .

  The dry film thickness of the cholesteric resin layer is preferably 10 μm or less, more preferably 2 to 7 μm, and even more preferably 3 to 6 μm. By changing the film thickness to 10 μm or less, a change in hue when observed from an oblique direction can be reduced. On the other hand, by setting the film thickness to 2 μm or more, sufficient reflectance can be obtained. The dry film thickness refers to the total film thickness of each layer when the cholesteric resin layer is two or more layers, and the film thickness when the cholesteric resin layer is one layer.

The transfer in the method (M3) can be performed by transferring a cholesteric resin layer formed on a substrate for forming a resin layer or an alignment film onto a layer to be transferred. Such transfer can be performed such that the layer to be transferred and the cholesteric resin layer are attached via an adhesive layer or an adhesive layer. Specifically, the layer to be transferred can be a quarter wavelength plate, for example.
Prior to transfer, the pressure-sensitive adhesive layer or adhesive layer can be provided in advance on either one or both of the surfaces to be transferred and the opposing surfaces of the cholesteric resin layer.
When the cholesteric resin layer is formed on the alignment film, only the cholesteric resin layer may be transferred, or both the cholesteric resin layer and the alignment film may be transferred. From the viewpoint of easy peeling and prevention of orientation failure of the cholesteric resin layer, it is preferable to transfer both the cholesteric resin layer and the alignment film.

(Linear polarization separation element)
Examples of the linearly polarized light separating element having a stretched film include a multilayer film reflective polarizer, a diffuse reflective polarizer, and a wire grid polarizer. Examples of the multilayer film reflective polarizer include Vikuiti DBEF and DBEFD manufactured by 3M. An example of the diffuse reflection polarizer is DRPF.

(2.2.2. Light diffusion sheet)
The light diffusing sheet is an optical element having the property of diffusing incident light and improving the luminance in the front direction. Examples of the light diffusion sheet include those having at least one light diffusion layer that has irregularities on the surface of the transparent substrate and realizes light diffusion by the irregularities.

  The material of the transparent substrate used for the light diffusion sheet is, for example, total light transmittance among polymethyl methacrylate, polycarbonate, polyvinyl chloride, polyester, resin having an alicyclic structure, resin such as acetate resin, and glass. These are usually used in the form of a film or plate. Particularly preferred is a polyester film in terms of weather resistance and workability, and a biaxially stretched film can be preferably used for the purpose of improving heat resistance.

For example, the light diffusion layer is obtained by spreading a light diffusion layer composition containing a polymer and / or a polymerizable monomer and a light diffusion agent on the surface of a transparent substrate to obtain a layer of the light diffusion layer composition. It can be obtained by curing the layer of the layer composition.
Examples of the polymer used in the light diffusion layer composition include acrylic polymers and copolymers, silicone polymers, polyesters, polyurethanes, and the like. A preferred resin is an acrylic polymer having excellent light resistance. One kind of these polymers may be used, or two or more kinds may be used in combination at any ratio.

  As the polymerizable monomer used in the light diffusion layer composition, for example, a monofunctional or polyfunctional monomer having a (meth) acryloyl group can be used. Monofunctional monomers having a (meth) acryloyl group include, for example, ethylene oxide-modified phenol (meth) acrylate, propylene oxide-modified phenol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, propylene oxide-modified nonylphenol. (Meth) acrylate and the like. Examples of the polyfunctional monomer having a (meth) acryloyl group include di (meth) acrylate of ethylene oxide-modified neopentyl glycol, di (meth) acrylate of ethylene oxide-modified bisphenol A, and propylene oxide-modified bisphenol A. Examples include di (meth) acrylate, di (meth) acrylate of ethylene oxide-modified hydrogenated bisphenol A, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and propylene oxide-modified trimethylolpropane tri (meth) acrylate. Furthermore, examples of the monomer having a (meth) acryloyl group include monofunctional or polyfunctional polyester acrylate, urethane acrylate, and polyol acrylate. One kind of these polymerizable monomers may be used, or two or more kinds may be used in combination at any ratio.

  Among the above-mentioned polymers and polymerizable monomers, particularly preferred are acrylic resins having excellent weather resistance, more preferably acrylic polyurethane two-component curing type, and at least one polyurethane acrylate and a photopolymerization initiator. And those containing. Even if these contain a light-diffusion agent, adhesiveness with a transparent base material is good. Among them, it is preferable to use one having a high hydroxyl value that increases the crosslinking density.

The light diffusing agent used in the light diffusing layer composition is a particle having a property of diffusing light, and can be roughly classified into an inorganic filler and an organic filler. Examples of the inorganic filler include glass, silica, aluminum hydroxide, aluminum oxide, titanium oxide, zinc oxide, barium sulfate, magnesium silicate, and a mixture thereof. Examples of the organic filler include acrylic resin, polyurethane resin, polyvinyl chloride resin, polystyrene resin, polyacrylonitrile resin, polyamide resin, polysiloxane resin, melamine resin, benzoguanamine resin, fluorine resin, polycarbonate resin, silicone resin, polyethylene resin, Examples thereof include ethylene-vinyl acetate copolymer, acrylonitrile, and a cross-linked product thereof. Among these, as the organic filler, an acrylic resin, a polystyrene resin, a polysiloxane resin, and fine particles made of a crosslinked product thereof are preferable in terms of high dispersibility, high heat resistance, and no coloration (yellowing) during molding. . Among these, fine particles made of a crosslinked product of an acrylic resin are more preferable in terms of more excellent transparency.
Moreover, what consists of 2 or more types of materials as a light-diffusion agent may be used, and 2 or more types of light-diffusion agents may be mixed and used.

Examples of the shape of the light diffusing agent include a spherical shape, an ellipsoidal shape, a cubic shape, a needle shape, a rod shape, a spindle shape, a plate shape, a scale shape, and a fiber shape. Among these, a spherical shape or an elliptical shape close to a spherical shape is preferable in that the light diffusion direction can be made isotropic.
The light diffusing agent has a diameter of preferably 0.2 μm to 50 μm, more preferably 0.5 μm to 30.0 μm. In addition, when the diameter of a particle is not a perfect sphere, the diameter of a sphere having the same volume is substituted. In the case of a filler having a significantly different size in one direction such as a needle shape, a diameter of a circle having the same area as the cross-sectional area of the cross section perpendicular to the direction is substituted.

  Moreover, as a light-diffusion agent, the translucent particle demonstrated by the term of the porous light-diffusion body can also be used.

The ratio of the light diffusing agent dispersed in the light diffusing layer composition can be appropriately selected according to the thickness of the light diffusing layer. Usually, it is preferable to adjust the content of the light diffusing agent so that the haze value of the light diffusing sheet is 60% to 98%, and the content of the light diffusing agent is adjusted to be 65% to 90%. It is more preferable. By setting the haze within the above preferable range, it is possible to improve the luminance of the liquid crystal display device and suppress luminance unevenness.
Moreover, the light-diffusion layer composition can contain solvents, such as toluene, xylene, and ethyl acetate, as needed.

  Further, when a polymerizable monomer is used, a photopolymerization initiator or a photosensitizer can be arbitrarily used. Examples of the photopolymerization initiator include acetophenones, benzophenones, α-amyloxime esters, tetramethylchuranium monosulfide, thioxanthones, and the like. Examples of the photosensitizer include n-butylamine, triethylamine, and poly-n-butylphosphine. In addition, a photopolymerization initiator and a photosensitizer may each be used alone or in combination of two or more at any ratio.

You may mix a crosslinking agent with a light-diffusion layer composition further. Examples of the crosslinking agent include polyfunctional isocyanate crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, trimethylolpropane tolylene diisocyanate, and diphenylmethane triisocyanate. One type of crosslinking agent may be used, or two or more types may be used in combination at any ratio.
The amount of the crosslinking agent is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polymer and / or polymerizable monomer in the light diffusion layer composition. When the amount is less than 0.1 parts by weight, the effect of crosslinking the polymer is not exhibited, and foaming and peeling in a weather resistance test may be conspicuous. On the other hand, when the amount is more than 20 parts by weight, the curing of the polymer proceeds so much that the adhesion to the transparent substrate may be lowered.

The light diffusion layer composition is spread on the surface of a transparent substrate to obtain a light diffusion layer, and this layer is cured by a process such as drying, heating, energy ray irradiation, etc. A light diffusion sheet provided with a light diffusion layer on the material can be obtained.
Examples of the method for applying the light diffusion layer composition to the surface of the transparent substrate include known methods such as a spray method, a dipping method, a roll coater method, a curtain flow method, a wire bar method, and a gravure method.

  The film thickness of the light diffusion layer is usually 1 to 30 μm, preferably 5 to 20 μm, more preferably 7 to 15 μm.

(2.2.3. Light collecting sheet)
The condensing sheet is an optical element having a property of condensing incident light, and is usually a sheet provided with a hemispherical dot, a triangular prism, or a hemispherical stripe shape on a transparent substrate. As the condensing sheet, for example, a commercially available prism sheet such as BEF-II, BEF-III, RBEF (trade name, manufactured by Sumitomo 3M); SP50 / 24, UHII75, HII (trade name, manufactured by Dai Nippon Printing Co., Ltd.) M165, M268, M248 (trade names, manufactured by Mitsubishi Rayon Co., Ltd.); PTX, PTR (trade names, manufactured by SHINWHA); UTE, UTE25, UTE30 (trade names, manufactured by MNTtech); Sancrista R500050, R500125 Name, manufactured by Suntec Opto).

  As the transparent substrate used for the light collecting sheet, the same transparent substrate used for the light diffusion sheet can be used. Especially, the polyester film by which the biaxial stretching process was carried out similarly to a light-diffusion sheet can be used preferably.

(2.2.4 Wave plate)
The wave plate is an optical element that causes a phase difference in light incident thereon. Examples of the wavelength plate include a half-wave plate that generates a phase difference of 180 °, a quarter-wave plate that generates a phase difference of 90 °, and the like. The wave plate is often manufactured through a stretching process and usually corresponds to the stretched film according to the present invention. In addition, the liquid crystal display device usually includes a quarter wavelength plate as a wavelength plate, and in particular, often includes a quarter wavelength plate in combination with a circularly polarized light separating element.

  As the quarter wavelength plate, for example, a stretched film formed by stretching a film-like polymer can be used. As a preferable example, a quarter wavelength plate formed by stretching a resin film including a styrene resin layer can be exemplified. More preferable examples include the optically anisotropic elements described below.

  The quarter-wave plate can set the retardation Re (hereinafter sometimes abbreviated as “Re”) in the front direction to substantially the quarter wavelength of transmitted light. Here, the wavelength range of the transmitted light can be a desired range required for the composite optical member, and specifically, for example, 400 nm to 700 nm. Further, the retardation Re in the front direction is approximately ¼ wavelength of transmitted light, and the Re value is ± 65 nm from the ¼ value of the center value in the center value of the wavelength range of transmitted light, preferably It means ± 30 nm, more preferably ± 10 nm. By having such a retardation value, a polarization conversion function, that is, a function of converting circularly polarized light into linearly polarized light can be exhibited.

  The quarter-wave plate desirably has a retardation Rth in the thickness direction (hereinafter sometimes abbreviated as “Rth”) of less than 0 nm. The value of retardation Rth in the thickness direction is preferably −30 nm to −1000 nm, more preferably −50 nm to −300 nm, in the central value of the wavelength range of transmitted light. By adopting such an optically anisotropic element having an Re value and Rth, it is possible to reduce color unevenness of emitted light while improving brightness and reducing brightness unevenness.

Here, the retardation Re in the front direction is represented by the formula I: Re = (nx−ny) × d (where nx is a direction perpendicular to the thickness direction (in-plane direction)) and gives the maximum refractive index. Ny represents a refractive index in a direction perpendicular to the thickness direction (in-plane direction) and perpendicular to nx, and d represents a film thickness). The retardation Rth in the thickness direction is expressed by the formula II: Rth = {(nx + ny) / 2−nz} × d (where nx is a direction perpendicular to the thickness direction (in-plane direction)) and gives the maximum refractive index. Ny is the direction perpendicular to the thickness direction (in-plane direction) and perpendicular to nx, nz is the thickness direction refractive index, and d is the film thickness. )).
In addition, the retardation Re in the front direction and the retardation Rth in the thickness direction are measured using a commercially available phase difference measuring apparatus, and the optically anisotropic elements are spaced 100 mm apart in the longitudinal direction and the width direction (longitudinal or lateral length). If the distance is less than 200 mm, three points are specified at equal intervals in that direction), and measurement is performed in a lattice point shape over the entire surface, and the average value is obtained.

  Although the material of the optically anisotropic element which comprises a quarter wavelength plate is not specifically limited, What has the layer which consists of a styrene resin can be used preferably. Here, the styrene resin is a polymer resin having a styrene structure as a part or all of the repeating units, and a polystyrene or a copolymer of styrene and maleic anhydride can be preferably used.

  The molecular weight of the styrenic resin used for the optically anisotropic element is appropriately selected according to the purpose of use, but is the weight average molecular weight (Mw) of polyisoprene measured by gel permeation chromatography using cyclohexane as a solvent. Usually, 10,000 to 300,000, preferably 15,000 to 250,000, and more preferably 20,000 to 200,000.

  The optically anisotropic element preferably has a laminated structure of a layer made of the styrenic resin and a layer containing another thermoplastic resin. By having the laminated structure, it is possible to provide an element that has both the optical characteristics of the styrene resin and the mechanical strength of other thermoplastic resins. As the other thermoplastic resin, a resin having an alicyclic structure or a methacrylic resin can be suitably used.

  Examples of the resin having an alicyclic structure include alicyclic olefin polymers. The alicyclic olefin polymer is an amorphous olefin polymer having a cycloalkane structure or a cycloalkene structure in the main chain and / or side chain.

  The methacrylic resin is a polymer containing methacrylic acid ester as a main component, and examples thereof include a homopolymer of methacrylic acid ester and a copolymer of methacrylic acid ester and other monomers. As the methacrylic acid ester, alkyl methacrylate is usually used. In the case of a copolymer, acrylic acid esters, aromatic vinyl compounds, vinylcyan compounds, etc. are used as other monomers copolymerized with methacrylic acid esters.

  As a preferred specific embodiment of the quarter-wave plate, a multilayer film formed by laminating a film (b layer) made of another thermoplastic resin on both surfaces of a film (a layer) made of polystyrene resin is stretched. A stretched multilayer film can be mentioned. Hereinafter, this specific embodiment will be described.

  As the polystyrene resin constituting the a layer, the same “styrene resin” as described above can be used.

  The method of laminating the polystyrene resin that is the material of the a layer and the other thermoplastic resin that is the material of the b layer to form a multilayer film is not particularly limited, but is a coextrusion T-die method, coextrusion inflation Known methods such as a method of forming by coextrusion such as a method, a coextrusion lamination method, a film lamination forming method such as dry lamination, and a coating forming method may be appropriately used. Among these, a molding method by coextrusion is preferable from the viewpoints of production efficiency and that volatile components such as a solvent do not remain in the film. The extrusion temperature can be appropriately selected according to the type of the polystyrene resin used and the other thermoplastic resin.

  The multilayer film is formed by laminating the b layer on both surfaces of the a layer. An adhesive layer can be provided between the a layer and the b layer, but the a layer and the b layer are directly laminated (that is, a laminate having a three-layer structure of b layer / a layer / b layer). Is preferred. In the multilayer film, the thickness of the a layer and the b layer laminated on both sides thereof is not particularly limited, but preferably 10 to 300 μm and 10 to 400 μm, respectively.

  The stretched multilayer film is formed by stretching the multilayer film. The stretching can be preferably performed by uniaxial stretching or oblique stretching, and more preferably by uniaxial stretching or oblique stretching by a tenter.

  The thickness of the optically anisotropic element is preferably 50 to 1000 μm, more preferably 50 to 600 μm.

  The quarter wavelength plate itself may also have a function as an optical compensation layer, but may additionally have an optical compensation layer in addition to the quarter wavelength plate. As such an optical compensation layer, the same optical anisotropic element as described above can be used, and a homeotropic liquid crystal alignment film obtained by homeotropic alignment of liquid crystal molecules on a substrate and curing (Japanese Patent No. 399969). ), A nematic hybrid liquid crystal alignment film (Japanese Patent Laid-Open No. 2000-66192) obtained by curing a state in which liquid crystal molecules are nematic hybrid aligned on a substrate can be used.

(2.2.5. Other layers)
The optical sheet may include layers other than the reflective polarizer, the light diffusing sheet, the light collecting sheet, and the wave plate described above. For example, an adhesive layer for adhering optical elements constituting the optical sheet and between the optical sheet and the substrate; a protective film that imparts functions such as antifouling property and scratch resistance to the optical sheet, a hard coat layer, an anti-blocking layer Etc.

The pressure-sensitive adhesive layer can be a layer formed by laminating a pressure-sensitive adhesive composition containing a polymer that expresses pressure-sensitive adhesive (hereinafter sometimes simply referred to as “main polymer”) and curing it as necessary.
As the main polymer, for example, acrylic, urethane, or polyester polymers can be used.

  The molecular weight range of the main polymer is preferably 10,000 to 1,000,000, and more preferably 50,000 to 500,000 in terms of weight average molecular weight. When the weight average molecular weight is lower than 10,000, whitening of the adhesive layer tends to occur. On the other hand, if the weight average molecular weight is larger than 1,000,000, gelation tends to occur, and the viscosity of the adhesive layer solution is high and difficult to handle.

  The said adhesive composition can contain a light-diffusion agent as needed. The content of the light diffusing agent in the adhesive composition is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the main polymer.

  According to the kind of main polymer, another compounding agent can be further mix | blended with the said adhesive composition. Examples of other compounding agents include tackifiers, crosslinking agents or curing agents, antioxidants, antifoaming agents, and stabilizers.

  The film thickness of the pressure-sensitive adhesive layer is usually 5 to 30 μm, preferably 10 to 25 μm. Adhesive strength can be secured by setting the film thickness to 5 μm or more, while optical performance such as transmittance can be maintained by setting the film thickness to 30 μm or less.

(2.2.6. Other matters concerning optical sheet)
The number of optical sheets to be inserted between the porous light diffuser and the substrate may be not only one but also a plurality. By using a plurality of sheets, it is possible to improve the luminance and viewing angle characteristics of the liquid crystal display device.

  The optical sheet may be obtained by integrating two or more of the above-described reflective polarizer, light diffusion sheet, condensing sheet, wavelength plate, and the like. By integrating, it is possible to reduce process loss due to handling of a plurality of sheets so far. As an integration method, for example, a zero-gap joining method described in JP-T-2006-513352; an ultrasonic fusion, a laser fusion, or an adhesive described in JP-A-2007-79025 is used. A method of partially bonding two sheets described in JP 2007-148419 A through a light reflecting layer; point melting at two or more points in a plane described in JP 2007-225686 A Method of attaching; Method of joining or adhering two sheets described in Japanese Patent Application Laid-Open No. 2007-65358 at a part of the peripheral portion; Part of bonding two sheets described in Japanese Patent Application Laid-Open No. 2007-78881 A method of bonding by swelling with a solvent in a method; a method of thermocompression bonding of two sheets described in Japanese Patent No. 3709402; a method described in Japanese Patent Publication No. 2007-502010 A method of adhering a sheet having a sheet and a structural surface through an adhesive layer so that a part of the structural surface penetrates into the adhesive layer; the ineffectiveness of two sheets described in JP-T-2007-504489 A method of adhering a portion of a tab outside the area with an adhesive layer; an air layer is formed between the reflective polarizer and the structural surface material described in US Pat. Nos. 7,038,745 and 5,828,488. A method of bonding by thermocompression bonding; a method of bonding a body having a quadrilateral pyramid structure described in JP-T-2008-521030 and a base material portion having optical characteristics different from that.

(2.3. Substrate)
The substrate is a member that is paired with the porous light diffuser and supports the optical sheet so that the optical sheet is not deformed by sandwiching the optical sheet. In the present invention, a liquid crystal panel may be used as the substrate, or a member different from the liquid crystal panel may be used.
Hereinafter, the base material as a member different from the liquid crystal panel will be described, and the liquid crystal panel will be described separately.

  When a member different from the liquid crystal panel is used as the substrate, a substrate that transmits light emitted from the light source is used. Although the specific light transmittance is not uniform depending on the luminance required for the liquid crystal display device, the total light transmittance of the substrate is usually 60% or more, preferably 70% or more, more preferably 80% or more. The total light transmittance of the substrate is ideally 100%, but is usually 98% or less, and is actually 95% or less in view of cost and the like.

Examples of the material for the substrate include the same materials as the inorganic material and the organic material mentioned as the material for the porous light diffuser. Note that only one type of substrate material may be used, or two or more types may be used in combination at any ratio.
Furthermore, an additive may be included in the substrate. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, and a release agent. In addition, only 1 type may be used for an additive and it may use it combining 2 or more types by arbitrary ratios.

It is preferable that the substrate has such a rigidity that the optical sheet is not deformed such as bending. The specific strength may be set according to the shape, size, weight, etc. of the optical member. However, since the optical sheet may bend when the substrate is bent, it is preferable that the substrate has high bending rigidity. Specifically, the flexural rigidity of the substrate length 60 mm, width of 25mm, preferably 5 mN · ^{m 2} or more, more preferably 20 mN · ^{m 2} or more, 40 mN · ^{m 2} or more is particularly preferable. In addition, although there is no restriction | limiting in an upper limit, in reality, it is 200 mN * m < ² > or less.

  Moreover, it is preferable that the thickness of a board | substrate is 0.5 mm-5.0 mm. If the thickness is less than 0.5 mm, the rigidity is insufficient and the optical sheet may be deformed. If the thickness exceeds 5.0 mm, the optical member becomes thick, making it difficult to reduce the thickness and space of the liquid crystal display device.

  Although there is no restriction | limiting in the manufacturing method of a board | substrate, It is preferable to manufacture with the manufacturing method which does not pass through an extending | stretching process. Although it may cause a phase difference in the light transmitted through the substrate after the stretching process, it is preferable that the light emitted from the light source does not cause a phase difference after passing through the optical sheet. It is. The retardation exhibited by the substrate is usually 0.5 to 80 nm, preferably 0.8 to 50 nm, and more preferably 1 to 30 nm at a wavelength of 550 nm.

(2.4. Double-sided uneven sheet)
The double-sided uneven sheet is a member provided between the optical sheet and the substrate as necessary. Since the double-sided concavo-convex sheet has a structure in which translucent particles protrude on both the front surface and the back surface, a gap is formed between the optical sheet and the substrate, and the optical sheet and the substrate are in close contact with each other. Can be prevented.

  The double-sided uneven sheet usually has translucent particles on the surface of the substrate (hereinafter, sometimes referred to as “core substrate” for distinction from the above-mentioned substrate sandwiching the optical sheet). The particles protrude from the surface of the core substrate. As the core substrate provided in the double-sided uneven sheet, it is possible to use the same transparent substrate as the light diffusion sheet described above, and particularly preferably a polymethyl methacrylate resin, a resin having an alicyclic structure, or an acetate resin. A film or plate is used. On the other hand, as the light transmissive particles, the same light diffusing agent as described above can be used as one of the light diffusing agents of the light diffusing sheet.

  However, a sufficient gap is formed between the optical sheet and the core substrate of the double-sided concavo-convex sheet and between the core substrate of the double-sided concavo-convex sheet and the substrate on which the optical sheet is sandwiched so that the optical contact between the optical sheet and substrate In order to prevent it reliably, it is preferable that the degree to which translucent particles protrude from the core substrate of the double-sided uneven sheet is somewhat large. Specifically, the height of the irregularities formed by the translucent particles projecting on the surface of the double-sided irregular sheet is the maximum value Ra (max) of arithmetic average roughness (along various directions in the main surface). The maximum value of the arithmetic average roughness Ra) is preferably 0.1 μm to 5 μm. Moreover, in order to keep the arithmetic average roughness Ra of the surface of the double-sided uneven sheet within the above range, it is preferable to increase the average particle diameter of the translucent particles to a certain extent, specifically 1.0 μm to 20.0 μm.

  In addition, if the density of translucent particles existing on the surface of the double-sided uneven sheet (the number of translucent particles per unit area of the double-sided uneven sheet surface) is excessive, an inadvertent light diffusing function appears and is intended. There is a risk that optical action will not occur. Therefore, it is preferable that the density of the translucent particles present on the surface of the double-sided uneven sheet is low to some extent. Specifically, the pitch between the translucent particles is preferably in the range of 5.0 μm to 30.0 μm. Such a pitch can be obtained by calculating an average of five shortest distances between the end portions of adjacent translucent particles and calculating the average in a plurality of observation fields as necessary.

  The thickness of the double-sided uneven sheet is preferably in the range of 0.08 mm to 1.0 mm from the viewpoints of optical properties and appropriate strength and weight.

  The double-sided uneven sheet can be produced by providing a transparent particle dispersion layer on both sides of the core substrate with the same composition as the light diffusion sheet and the same production method.

(3. Support member)
As a material constituting the support member, for example, a thermoplastic elastomer or a thermoplastic resin can be used.

The thermoplastic elastomer has the same properties as vulcanized rubber at room temperature and has elasticity. The thermoplastic elastomer is a polymer material that can be molded using an existing molding machine at a high temperature in the same manner as a normal thermoplastic resin. Usually, a thermoplastic elastomer has both a rubber component having elasticity in a molecule, that is, a soft segment, and a molecular constraint component for preventing plastic deformation, that is, a hard segment. Various thermoplastic elastomers in which the soft segment and the hard segment are combined depending on the type, molecular weight, arrangement, and the like have been put into practical use.
Suitable thermoplastic elastomers include, for example, styrenic thermoplastic elastomers in which the hard segment is composed of polystyrene and the soft segment is composed of polybutadiene, hydrogenated polybutadiene, polyisoprene, etc .; the hard segment is composed of polyolefin and soft Olefin-based thermoplastic elastomer whose segment is composed of ethylene-propylene rubber; hard segment is composed of polymer chains composed of diisocyanate and short-chain glycol, and soft segment is composed of polymer chains composed of diisocyanate and polyol Urethane-based thermoplastic elastomers; polyester-based thermoplastic elastomers whose hard segments are composed of amorphous polyether with a glass transition temperature of -70 ° C or lower -: Polyamide thermoplastic elastomer with hard segment made of nylon polyamide and soft segment made of polyester or polyol; Hard segment made of fluororesin, soft segment made of fluoro rubber Fluorine-based thermoplastic elastomers; other vinyl chloride-based thermoplastic elastomers, silicon rubber, and the like can be used.

  Examples of the thermoplastic resin include acrylonitrile-butadiene-styrene (ABS) resin, α-methylstyrene ABS resin, phenylmaleimide ABS resin, acrylonitrile-acrylate-styrene resin, chlorinated polyethylene-acrylonitrile-styrene resin, acrylonitrile- Ethylene-styrene resin, polyphenol A polycarbonate resin, or the like can be used.

These materials may be used alone or in combination of two or more at an arbitrary ratio for the purpose of improving molding processability and mechanical properties.
In addition, for the purpose of suppressing luminance unevenness due to stray light, carbon black or pigment is mixed with the above thermoplastic elastomer or thermoplastic resin, or glass fiber or the like is mixed for the purpose of improving mechanical strength. You can also

The elastomer constituting the support member preferably has a tensile elastic modulus of 1 to 3000 MPa, and more preferably 20 to 2000 MPa. When the tensile elastic modulus is less than 1 MPa, the function as a support member is hardly exhibited, and a resin having a tensile modulus greater than 3000 MPa is insufficient in toughness, becomes brittle and easily breaks.
Among these, styrene-ethylene-butylene-styrene block copolymer resin and styrene-butadiene-styrene block copolymer resin are suitable as the thermoplastic elastomer, and bisphenol A polycarbonate resin is preferred as the thermoplastic resin. It can be used suitably.

(4. Frame member)
The frame member can be integrally formed from the same material as the support member. Further, the frame member can be integrated after being molded separately from the support member. In the case of comprising the same material as the support member, examples of the material include acrylonitrile-butadiene-styrene (ABS) resin, α-methylstyrene-based ABS resin, phenylmaleimide-based ABS resin, acrylonitrile-acrylate-styrene resin, A chlorinated polyethylene-acrylonitrile-styrene resin, an acrylonitrile-ethylene-styrene resin, a bisphenol A polycarbonate resin, or the like can be used. Moreover, for the purpose of suppressing luminance unevenness due to reflected light, carbon black, pigment, or the like can be mixed with the resin, or glass fiber or the like can be mixed for the purpose of improving mechanical strength.
Further, when the frame member is molded separately from the optical member, examples of the material include metal materials such as SUS and aluminum in addition to the resin.

When the frame member and the support member are formed as separate members and then integrated, as an integration method, a double-sided tape or an adhesive is used at the boundary portion 5U between the existing frame member 7 and the support member 5 in FIG. And a method of fixing the support member 5 using an adhesive.
In addition, as a method of manufacturing the frame member and the support member from the same material, a method of processing a groove corresponding to the shape of the support member in a mold and integrally forming the injection molding can be given.

(5. Liquid crystal panel)
The liquid crystal panel includes, for example, twisted nematic (TN) mode, super twisted nematic (STN) mode, hybrid alignment nematic (HAN) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, in-plane switching (IPS). ) Mode, and optically compensated bi-fidelity (OCB) mode.

  Moreover, when using a liquid crystal panel as a board | substrate which pinches | interposes an optical sheet, the arbitrary liquid crystal panels which have the rigidity which can be supported so that an optical sheet may not deform | transform can be used as a liquid crystal panel. The thickness of the liquid crystal panel used as the substrate is preferably 0.5 mm to 3.0 mm, more preferably 0.7 mm to 2.0 mm.

[Use]
The application of the liquid crystal display device of the present invention having the optical member of the present invention is not particularly limited, and can be used as a display device for televisions, personal computers, and other various electronic devices. In particular, a large-screen display device such as a television is preferable because it can exhibit better durability than conventional ones.

  The present invention is not limited to the exemplification of the above-described embodiment, and can be modified within the scope of the claims of the present application and its equivalent scope. In addition, the optical member and the liquid crystal display device of the present invention can further include arbitrary components for configuring the optical member and the liquid crystal display device.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not limited to the following Example. In the following, “parts” relating to the quantity ratio of the components represents parts by weight unless otherwise specified.

<Example 1>
(Preparation of substrate)
A commercially available acrylic resin plate (manufactured by Sumitomo Chemical Co., Ltd .; trade name Sumipex; thickness 0.5 mm) was used as the substrate.

(Preparation of optical sheet)
(I. Preparation of substrate-reflective polarizer laminate)
One side of a sheet-like substrate (trade name “Zeonor ZF14-100”, manufactured by Nippon Zeon Co., Ltd.) was subjected to corona discharge treatment so that the wetting index was 56 mN / m. Polyvinyl alcohol (trade name “Poval PVA203”, manufactured by Kuraray Co., Ltd.) is applied to this corona discharge treated surface with a # 2 bar coater and dried at 120 ° C. for 5 minutes to produce a dry film having a thickness of 0.2 μm. did. By rubbing the dry film in one direction, a substrate having an alignment film was obtained.

  Rod-shaped liquid crystal compound (compound 29.1 parts represented by the following formula (C3), compound 7.28 parts represented by the following formula (C4), photopolymerization initiator (trade name “IRG907, manufactured by Ciba Specialty Chemicals Co., Ltd.) ”) 1.20 parts, 2.22 parts of chiral agent (trade name“ LC756 ”manufactured by BASF Corporation), 0.04 part of surfactant KH40 (manufactured by Seimi Chemical), and 60.00 parts of 2-butanone (solvent) Were mixed to prepare a cholesteric liquid crystal composition.

This cholesteric liquid crystal composition was applied to the surface having the alignment film of the base material having the alignment film prepared above with a die coater. The coating film is subjected to an orientation treatment at 100 ° C. for 5 minutes, and the coating film is subjected to a process of irradiation with weak ultraviolet rays of 0.1 to 45 mJ / cm ² followed by a heating treatment at 100 ° C. for 1 minute. After repeating twice, 800 mJ / cm ² ultraviolet rays were irradiated in a nitrogen atmosphere to form a cholesteric resin layer having a dry film thickness of 5.3 μm, thereby obtaining a substrate-reflective polarizer laminate.

(Ii. Preparation of quarter wave plate)
A monomer composition composed of 97.8% by weight of methyl methacrylate and 2.2% by weight of methyl acrylate was polymerized by a bulk polymerization method to obtain resin pellets.
Rubber particles were produced according to Example 3 of JP-B-55-27576. This rubber particle has a spherical three-layer structure, the core inner layer is a crosslinked polymer of methyl methacrylate and a small amount of allyl methacrylate, and the inner layer is composed of butyl acrylate and styrene as main components and a small amount of acrylic acid. It is a soft elastic copolymer obtained by crosslinking and copolymerizing allyl, and the outer layer is a hard polymer of methyl methacrylate and a small amount of ethyl acrylate. The average particle size of the inner layer was 0.19 μm, and the particle size including the outer layer was 0.22 μm.

70 parts of the resin pellets and 30 parts of the rubber particles were mixed and melt kneaded with a twin screw extruder to obtain a methacrylic acid ester polymer composition A (glass transition temperature 105 ° C.).
By coextruding the methacrylic acid ester polymer composition A (b layer) and the styrene maleic anhydride copolymer (glass transition temperature 130 ° C.) (a layer) at a temperature of 280 ° C., the b layer-a layer A multilayer film having a three-layer structure of -b layers, each layer having an average thickness of 45-70-45 (μm) was obtained. This multilayer film was tenter uniaxially stretched at a stretching temperature of 128 ° C., a stretching ratio of 1.4 times, and a stretching speed of 10 m / min to obtain a quarter-wave plate as a stretched multilayer film. Further, one side of this quarter-wave plate was subjected to corona discharge treatment so that the wetting index was 56 dyne / cm.
With respect to the retardation value of the obtained quarter-wave plate at a wavelength of 550 nm, the retardation Rth in the thickness direction was −118 nm, and the retardation Re in the in-plane direction was 140 nm.

(Iii. Preparation of diffusion adhesive layer)
Polyethylene terephthalate separator (trade name “PET50AL”, manufactured by Lintec Corporation), base resin (trade name “SK Dyne 2094”, manufactured by Soken Chemical Co., Ltd., acrylic ester copolymer, solid content 25%, solvent : Ethyl acetate / 2-butanone = 93/7)) 400 parts, polyfunctional epoxy crosslinking agent (trade name “E-AX”, manufactured by Soken Chemical Co., Ltd.) 1.1 parts and fine powder (trade name “Chemisnow MX300”) (Manufactured by Soken Chemical Co., Ltd.) A pressure-sensitive adhesive composition comprising 4.3 parts was applied using a die coater, dried at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm, and a separator. -The laminated body (L3) which has a layer structure of a diffusion adhesion layer was obtained.

(Iv. Polarized laminate)
The corona discharge-treated surface of the quarter-wave plate obtained in (ii. Production of quarter-wave plate) and the diffusion adhesive layer side of the laminate (L3) obtained in (iii. Production of diffusion-adhesive layer) The laminated body (L51) which has a layer structure of 1/4 wavelength plate-diffusion adhesion layer-separator was bonded together.

  The surface of the cholesteric resin layer of the substrate-reflective polarizer laminate obtained in the above (i. Preparation of substrate-reflective polarizer laminate) is subjected to corona discharge treatment so that the wetting index is 60 mN / m. did. The separator of the laminate (L51) is peeled from the diffusion adhesive layer, and the exposed diffusion adhesive layer and the corona discharge treated surface of the substrate-reflective polarizer laminate are bonded together to form a quarter-wave plate-diffusion adhesive. A laminate (L52) having a layer configuration of layer-cholesteric resin layer-alignment film-base material was obtained.

  Then, the base material was peeled from the laminate (L52), and an optical sheet was obtained as a circularly polarized light separating / reflecting element having a layer configuration of ¼ wavelength plate-diffusion adhesive layer-cholesteric resin layer.

(Preparation of porous light diffuser)
100 parts of ZEONOR 1060R (manufactured by ZEON CORPORATION) are dissolved in 283 parts of cyclohexane and 283 parts of toluene, and the solution is dried on a transparent acrylic 1.5 mm thick plate (Sumipex, manufactured by Sumitomo Chemical Co., Ltd.) with a dry film thickness of 23 to 25 μm. Expanded to become. After the solution development, the plate was left to stand in an environment of 60 ° C. and 70% RH for 30 minutes, and then further dried at 80 ° C. for 1 hour to produce a porous light diffuser having a thickness of 1.5 mm.
Transmission observation was performed with a microscope (magnification 200 times), and the occupancy ratio of the surface of the porous light diffuser was measured within a field of 580 μm × 460 μm. The measurement was performed at five points in the plane of the porous light diffuser, and the average value of the hole occupation ratio calculated at each point was calculated as the hole occupation ratio of the porous light diffuser. The vacancy occupation ratio on the surface of the obtained porous light diffuser was 21.12%.
Further, the minimum pore diameter and the load length ratio Rmr (c) on the surface of the obtained porous light diffuser were measured using a digital microscope (manufactured by KEYENCE, VK9500). Load length ratio calculated by five-point cross-section measurement with five-point cross-section measurement in the longitudinal direction within the observation field of view 340 μm × 290 μm, with the smallest hole diameter in the five-point cross-section measurement being the smallest hole diameter The average value of Rmr (c) was defined as the load length ratio Rmr (c). The minimum hole diameter was 25.9 μm, and the load length ratio Rmr (c) was 63.9%.

(Assembling optical components)
The substrate was cut into a 952 mm × 560 mm rectangle.
The optical sheet was cut into a 933 mm × 541 mm rectangle.
The porous light diffuser was cut into a rectangle of 952 mm × 560 mm.
The cut porous light diffuser, the optical sheet, and the substrate were laminated in this order to obtain an optical member. During the lamination, the edge of the optical sheet was adjusted to be located at least 9.5 mm inside the edge of the substrate and the porous light diffuser in any of the four sides of the rectangle. As a result, the edge 42E of the optical sheet was located 3 mm outside the inner edge 41P _in of the backlight housing (see FIG. 2).

(Preparation of support member)
The support member is a styrene-ethylene-butylene-styrene block copolymer resin (trade name “Tuftec H1053”, manufactured by Asahi Kasei Chemicals Corporation, tensile elastic modulus 30.0 MPa (JIS K7113-1995)) in a sheet form having a thickness of 2.6 mm. Extruded. Two square columnar members with a length of 945 mm, a width of 5.0 mm, and a thickness of 2.6 mm, and two square columnar members with a length of 551 mm, a width of 4.0 mm, and a thickness of 2.6 mm. These were cut out and used as support members.

(Adjustment of support member-frame member)
From a commercially available liquid crystal television (manufactured by Sharp Corporation, trade name “LC42RX1W”), a liquid crystal panel, a frame member to which the liquid crystal panel was attached, and all the parts provided between the liquid crystal panel and the backlight housing The optical member (diffusion sheet and brightness enhancement sheet) was removed.
The packing attached to the frame member is peeled off, and instead the support member obtained above is pasted through a double-sided tape with a thickness of 60 μm to prepare a part in which the liquid crystal panel, the support member and the frame member are integrated. did. As shown schematically in FIG. 6, the support members are arranged one by one on the long side and one on the short side of the frame member. The position of the optical member was adjusted so that the support member to be attached later hits the outer edge of the optical member, and the optical member was placed on the backlight housing. From above, a liquid crystal panel, a support member, and a frame member are fitted together, and the outer edge portion of the optical member is sandwiched between the support member and the backlight housing, so that the liquid crystal display as shown in FIG. The device was assembled. At this time, the edge of the optical sheet is positioned inside the outer edge of the portion where the support member and the backlight housing sandwich the optical member. As a result, the edge 42E of the optical sheet was located outside the inner edge 41P _in (FIG. 2) of the backlight housing.

(Evaluation 1: Measurement of stress applied to edge of optical sheet)
A pressure measurement film (product name: Fuji Prescale, Fuji Photo Film Co., Ltd.) is spread between the optical sheet and the substrate so that it is 50 mm larger than the outer dimension of the optical sheet and assembled as a liquid crystal display device. The stress applied to the edge of the optical sheet was measured by comparing the degree of discoloration with the continuous pressure standard chart.
As a result of the measurement, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.

(Evaluation 2: Evaluation of image quality)
The assembled liquid crystal display device was left at a temperature of 40 ° C. and a humidity of 90% RH for 120 hours. Thereafter, the backlight was turned on, and the liquid crystal panel was observed in white display. As a result of observation, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was observed in the display surface.

<Example 2>
An optical member was prepared and a liquid crystal display device was assembled in the same manner as in Example 1 except that the stress applied to the edge of the optical sheet was made stronger than that in Example 1 by adjusting the position of the frame member.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.8 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 3>
From a liquid crystal television (made by Sharp Corporation, trade name “LC42RX1W”), a liquid crystal panel, a frame member to which the liquid crystal panel was attached, and all optical members provided between the liquid crystal panel and the backlight housing (Diffusion sheet and brightness enhancement sheet) were removed.
An optical member was prepared in the same manner as in Example 1 except that the removed liquid crystal panel was used as a substrate.
The prepared optical member was placed on the backlight housing. Then, the position was adjusted so that the optical member could be sandwiched between the frame member and the backlight housing, the prepared frame member was mounted, and a liquid crystal display device as shown in FIG. 7 was assembled. At this time, the edge of the optical sheet is positioned on the inner side of the outer edge of the portion where the frame member and the backlight housing as the support members sandwich the optical member. As a result, the edge 42E of the optical sheet was located outside the inner edge 41P _in (FIG. 8) of the backlight housing.

When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 4>
As an optical sheet, an optical member was prepared in the same manner as in Example 1 except that a linearly polarized light separating / reflecting polarizer having a commercially available stretched film (manufactured by 3M, trade name “DBEF M”, thickness 132 μm) was used. A liquid crystal display device was assembled.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.4 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 5>
As an optical sheet, an optical member was prepared in the same manner as in Example 1 except that a light diffusion sheet having a commercially available stretched film as a base material (manufactured by Kimoto Co., Ltd., trade name “LIGHT-UP GM3”, thickness 100 μm) was used. Prepared and assembled a liquid crystal display.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 6>
As an optical sheet, an optical member was prepared in the same manner as in Example 1 except that a condensing sheet (manufactured by 3M, trade name “BEF-II”, thickness 140 μm) having a commercially available stretched film as a base material was used. A liquid crystal display device was assembled.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 7>
100 parts of ZEONOR 1060R (manufactured by ZEON CORPORATION) was dissolved in 354.5 parts of cyclohexane, and this polymer solution was developed on a transparent acrylic 1.5 mm thick plate (Sumipex, manufactured by Sumitomo Chemical Co., Ltd.). Distilled water was sprayed for 5 minutes with a spray gun (model W-101-102P, manufactured by Anest Iwata) while heating the plate to 40 ° C in an atmosphere of 23 ° C and 70% relative humidity. Left alone. The plate was further heated at 80 ° C. for 1 hour to sufficiently evaporate residual moisture, and a porous light diffuser was produced.
An optical member was prepared in the same manner as in Example 1 except that the porous light diffuser produced as described above was used as the porous light diffuser, and a liquid crystal display device was assembled. The thickness of the porous light diffuser prepared in this example was 1.5 mm, and the vacancy occupation ratio on the surface was 31.5%.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 8>
(8-1: Pellet A for light diffusion plate)
99.7 parts of a resin having an alicyclic structure (manufactured by ZEON Corporation, ZEONOR 1060R, water absorption 0.01%) and 0.3 part of fine particles composed of a crosslinked product of a polysiloxane polymer having an average particle diameter of 2 μm The mixture was kneaded with a twin-screw extruder, extruded into a strand shape, and cut with a pelletizer to produce a light diffusion plate pellet A. Using this light diffusing plate pellet A as a raw material, a 100 mm × 50 mm test plate having a smooth thickness of 2 mm on both sides was molded using an injection molding machine (clamping force 1000 kN). The total light transmittance and haze of the test plate were measured using an integrating sphere type color difference turbidimeter based on JIS K7361-1 and JIS K7136. The test plate had a total light transmittance of 85% and a haze of 90%.

(8-2: Molding of light diffusion plate)
A mold part having a predetermined shape is mounted on an injection molding machine (clamping force 4,410 kN), and a cylinder for a light diffusion plate pellet A obtained in (8-1: Light diffusion plate pellet A) is used as a raw material. Injection molding was performed under conditions of a temperature of 280 ° C. and a mold temperature of 85 ° C. to form a light diffusion plate. The obtained light diffusion plate was a rectangular flat plate having a thickness of 2 mm and 950 mm × 550 mm. The total light transmittance of this light diffusion plate was measured and found to be 60.0%.

(8-3: Preparation of adhesive layer)
On the other hand, 400 parts of base resin (trade name “SK Dyne 2094”) and a crosslinking agent were used in the same separator as that used in (iii. Preparation of diffusion adhesive layer) in the section (Preparation of optical sheet) of Example 1. (Product name “E-AX”, manufactured by Soken Chemical Co., Ltd., polyfunctional epoxy cross-linking agent) A mixture with 1.1 parts was applied using a die coater, dried at 100 ° C. for 2 minutes, and a separator film A laminate (L4) having a layer structure of an adhesive layer having a thickness of 10 μm was obtained.

(8-4: Preparation of porous light diffuser)
A porous light diffuser was produced in the same manner as in Example 7 except that a PET film (Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.) was used instead of the transparent acrylic 1.5 mm thick plate used in Example 7. The thickness of the prepared porous light diffuser was 100 μm.

(8-5: Production of laminate)
The surface of the light diffusing plate obtained in (8-2: Molding of the light diffusing plate) where the trace of the gate (entrance where the resin flows into the mold) does not remain is subjected to corona discharge treatment so that the wetting index is 60 mN / m. The adhesive layer obtained in (8-3: Preparation of adhesive layer) was bonded, the separator was peeled off, and the porous light diffuser prepared in (8-4: Preparation of porous light diffuser) A surface different from the surface was bonded to obtain a laminate of a light diffusion plate and a porous light diffuser.

(8-6: Assembly of liquid crystal display device)
An optical member was prepared in the same manner as in Example 7 except that the laminated body of the light diffusion plate and the porous light diffuser was used instead of the porous light diffuser used in Example 7, and a liquid crystal display device was prepared. Assembled. The laminated body was arranged from the light source side in the order of the light diffusing plate and the porous light diffusing body. Moreover, the thickness of the laminated body of the light diffusing plate and porous light diffusing body prepared in this example was 2.1 mm.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 1.1 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Example 9>
Between the optical sheet and the acrylic plate 0.5 mm thickness as the substrate, double-sided uneven sheet (OPCON PCLR # 100, thickness 110 μm, haze 22.8%, total light transmittance 94.9%, manufactured by Eiwa Co., Ltd.) An optical member was prepared in the same manner as in Example 7 except that was inserted, and a liquid crystal display device was assembled. When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.5 MPa was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, no color unevenness due to wrinkles or undulations of the optical sheet was found in the display surface.

<Comparative Example 1>
An optical member was prepared in the same manner as in Example 1, and a liquid crystal display device was assembled in the same manner as in Example 1 except that the position of the frame member was adjusted so that no pressure was applied to the outer edge of the optical member.
When the stress applied to the edge of the optical sheet was measured, no stress was applied to the edge of the optical sheet.
When the image quality was evaluated, in the image display apparatus of this example, color unevenness due to wrinkles and undulations of the optical sheet was observed in the display surface. This is presumably because the optical sheet was deformed such as wrinkles and undulations because no stress was applied to the edge of the optical sheet.

<Comparative example 2>
Instead of the porous light diffuser, a commercially available flat light diffusion plate (manufactured by Optes Inc., trade name “ZEONOR”, thickness 2 mm, arithmetic average roughness 0.35 μm, ten-point average roughness 2.4 μm) is used. An optical member was prepared in the same manner as in Example 1 except that the liquid crystal display device was assembled.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
In addition, when the image quality was evaluated, in the image display apparatus of this example, color unevenness caused by wrinkles and undulations of the optical sheet was observed in the display surface. This is presumably because sticking has occurred between the light diffusing plate and the optical sheet.

<Comparative Example 3>
Example except that a commercially available light diffusion plate with a pattern (manufactured by Optes Co., Ltd., trade name “ZEONOR”, thickness 2 mm, apex angle 110 °, pitch 70 μm) was used instead of the porous light diffuser. In the same manner as in No. 1, an optical member was prepared and a liquid crystal display device was assembled.
When the stress applied to the edge of the optical sheet was measured, it was found that a stress of 0.3 MPa was applied to the edge of the optical sheet.
In addition, when the image quality was evaluated, in the image display apparatus of this example, color unevenness caused by wrinkles and undulations of the optical sheet was observed in the display surface. This is presumably because the optical sheet is curved along the pattern of the surface of the light diffusion plate.

<Comparative example 4>
The optical member was prepared in the same manner as in Example 1 except that the substrate was not used, and the same as in Example 1 except that the position of the frame member was adjusted so that no pressure was applied to the outer edge of the optical member. A liquid crystal display device was assembled.
When the stress applied to the edge of the optical sheet was measured, no stress was applied to the edge of the optical sheet.
In addition, when the image quality was evaluated, in the image display apparatus of this example, color unevenness caused by wrinkles and undulations of the optical sheet was observed in the display surface. This is presumably because the suppression by the substrate is lost and the optical sheet is wrinkled.

1, 101, 201, 301 Liquid crystal display device 2 Linear light source (light source)
DESCRIPTION OF SYMBOLS 3 Backlight housing | casing 3A Opening of backlight housing | casing 3B Bottom plate part of backlight housing | casing 3F Peripheral part of backlight housing | casing 3H, 7H Bolt hole 3S Side plate part of backlight housing | casing 4,104,204,304 Optical member 4e, 104e Supporting member edges 4A to 4D Optical member side 5 Supporting member 5U Upper surface of supporting member 6 Bolt 7 Frame member 7A Opening of frame member 7C Ceiling part of frame member 7H Bolt hole 7L Surface of frame member 8 lower frame member 9 LCD panel 9P portion 9P _in the substrate edge 41 porous light diffuser 41S porous inner edge portion 9P _out substrate is sandwiched support member of the portion sandwiched support member liquid crystal panel is sandwiched by the frame member portion 41P _in the porous light diffuser is back surface 41P porous light diffuser sex light diffuser is sandwiched backlight housing Inner edge 43P of the portion part of the inner edge 41P _out porous light outer edge 42 optical sheet 42E optical sheet edge 43 substrate 43P _in the substrate portion diffuser is sandwiched backlight housing sandwiched site housing is sandwiched support member Outer edge of the portion where the _out substrate is sandwiched between the support members 44 Double-sided uneven sheet

Claims (11)

An optical member that is sandwiched and attached to the support member of a liquid crystal display device that includes a light source and a pair of support members,
A porous light diffuser having pores on at least a surface far from the light source, an optical sheet having a stretched film, and a substrate are provided in this order from the light source side,
An optical member, wherein stress applied to an edge of the optical sheet when the optical member is mounted on the liquid crystal display device is 0.2 MPa or more.   2. The optical member according to claim 1, wherein a pore occupation ratio of a surface of the porous light diffuser having the pores is 5 to 70%.   The optical member according to claim 1 or 2, wherein the porous light diffuser contains translucent particles therein.   The optical member according to claim 1, wherein the substrate has a thickness of 0.1 mm to 5.0 mm.   The optical member according to claim 1, wherein the optical sheet has a reflective polarizer.   The optical member according to claim 1, wherein the optical sheet has a light diffusion sheet.   The optical member according to claim 1, wherein the optical sheet has a condensing sheet.   The optical member according to claim 1, wherein the substrate is a liquid crystal panel.   The optical member according to any one of claims 1 to 8, further comprising a double-sided concavo-convex sheet having translucent particles protruding on both sides between the optical sheet and the substrate.   The optical member according to any one of claims 1 to 9, wherein an edge of the optical sheet is on an inner side of an outer edge of a portion sandwiched between the porous light diffuser and the support member of the substrate.   A liquid crystal display device comprising the optical member according to claim 1.

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