JP2012118235A - Optical member, optical module, liquid crystal display panel and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member having a polarizer and capable of changing an advancing direction of light.SOLUTION: An optical member 18 includes a polarizing plate 40 having a polarizer 41, and an optical sheet 60 disposed opposing to the polarizing plate and joined to the polarizing plate. At least one face, in a face of the polarizing plate opposing to the optical sheet and a face of the optical sheet opposing to the polarizing plate, is formed into a concavo-convex pattern. The one face is joined to the other face via at least a part of projections in the concavo-convex pattern that constitutes the one face, forming a space V between the polarizing plate and the optical sheet.

Description

  The present invention relates to an optical member having a polarizer, and more particularly to an optical member that can change the traveling direction of light. The present invention also relates to an optical module, a liquid crystal display panel and a display device including such an optical member.

  Today, display devices including a liquid crystal display panel and a surface light source device that illuminates the liquid crystal display panel from the back side are widely used.

  As shown in FIG. 22, the surface light source device includes a light source including a light emitter and a large number of optical sheets for changing the traveling direction of light from the light emitter, and liquid crystal with desired optical characteristics. Designed to illuminate the display panel. In the example of the surface light source device shown in FIG. 22, a diffusion plate A, a lower diffusion sheet B, a condensing sheet C, and an upper diffusion sheet D are provided in order from the light emitter 26 side of the light source 25. Among these, the condensing sheet C has the function (condensing function) which narrows the advancing direction of light to the front direction and improves the luminance in the front direction. Further, the diffusion plate A, the lower diffusion sheet B, and the upper diffusion sheet D have a light diffusion function of diffusing light from the light emitter 26 of the light source 25 to hide the image of the light emitter 26 (make it inconspicuous). .

  On the other hand, as shown in FIG. 22, the liquid crystal display panel includes a liquid crystal cell 11 capable of controlling the orientation of the liquid crystal for each pixel, and a light incident side polarizing plate (hereinafter referred to as the light incident side of the liquid crystal cell). 1, and a light output side polarizing plate (hereinafter also referred to as an upper polarizing plate) 12 disposed on the light output side of the liquid crystal cell 11. The pair of polarizing plates 12 and 13 is a polarizer that transmits light of a specific polarization component and absorbs light of components other than the specific polarization component, a protective film that is bonded to the polarizer and protects the polarizer, have.

  Of these, the protective film is usually formed as a simple translucent film due to cost constraints, and does not positively affect the transmitted light. In addition, a protective film with an optical function does not exist, but considering the adhesive function with the polarizer and the protective function to protect the polarizer, the protective film on the side that does not actually face the polarizer The surface is merely a mat surface (for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-258013

  However, a sufficient diffusion function cannot be imparted to the protective film to the extent that one surface of the protective film is matted. That is, in the conventional polarizing plate which consists of a polarizer and a protective film, the advancing direction of light cannot be changed positively. On the other hand, if the optical member including the polarizer can be provided with a function of actively changing the traveling direction of light, the degree of freedom in designing the luminance characteristics and viewing angle characteristics of the display device is remarkably increased. Can be improved.

  The present invention has been made in consideration of such points, and an object thereof is to provide an optical member having a polarizer and capable of changing the traveling direction of light.

  By the way, various problems have arisen because the surface light source device (display device) includes a large number of optical sheets. First, as the number of optical sheets increases, the manufacturing cost of the display device directly increases. In addition, when the surface light source device (display device) includes a large number of optical sheets, positioning between the optical sheets performed when the surface light source device is assembled and positioning between the optical sheet and the light emitter are complicated. This also increases the manufacturing cost of the display device.

  Further, each optical sheet does not transmit all incident light, and a part of the incident light is reflected by the optical sheet. The light reflected by the optical sheet can be reflected by the reflecting plate 21 (see FIG. 22) provided on the back surface of the light emitter 26 or another optical sheet and reused. However, part of the light is absorbed each time the light is reflected by each optical sheet. Such reflection loss increases significantly only when the number of optical sheets increases by one. That is, when a surface light source device (display device) includes a large number of optical sheets, the utilization efficiency of light emitted from the light emitter of the light source is significantly reduced.

  Furthermore, the optical sheet is heated by heat generated from the light emitter, and the optical sheet may be bent, bent, warped, or the like. At this time, in a surface light source device (display device) provided with a large number of optical sheets, adjacent optical sheets may contact or rub against each other. The portion where the optical sheets are in close contact with each other can no longer exhibit the expected optical function, and the close contact portion may be visually recognized. In addition, when the optical sheets are rubbed with each other, the optical sheets may be scratched, and further, residue may be generated, and the display image quality is remarkably deteriorated.

  If one or more of the many optical sheets incorporated in the conventional surface light source device can be reduced by the present invention, the above problems caused by the existence of the many optical sheets can be reduced or eliminated. Very convenient.

The optical member according to the present invention is
A polarizing plate having a polarizer;
An optical sheet disposed opposite to the polarizing plate and bonded to the polarizing plate,
At least one of the surface of the polarizing plate facing the optical sheet and the surface of the optical sheet facing the polarizing plate is formed as a surface having irregularities,
The one surface is bonded to the other surface via at least a part of the convex portions of the unevenness forming the surface, and a gap is formed between the polarizing plate and the optical sheet.

  In the optical member according to the present invention, the polarizing plate further includes a protective film that forms a surface facing the optical sheet, and the protective film is dispersed in the main part and a main part made of a resin material. And a diffusion component.

  In the optical member according to the present invention, the surface of the protective film facing the optical sheet has at least one of irregularities formed due to the presence of the diffusion component and irregularities formed by shaping. May be.

  In the optical member according to the present invention, the optical sheet may include a sheet-like main body portion and a plurality of unit optical elements arranged on the main body portion.

  In the optical member according to the present invention, the unit optical element of the optical sheet forms a surface facing the polarizing plate of the optical sheet, and the optical sheet is attached to the polarizing plate via the top of the unit optical element. It may be joined.

  In the optical member according to the present invention, the unit optical element may be provided on a surface of the main body portion that does not face the polarizing plate.

  In the optical member according to the present invention, the surface of the main body portion on which the unit optical element is not provided may have an uneven surface that faces the polarizing plate.

The optical member according to the present invention is disposed on a side of the optical sheet that does not face the polarizing plate, and further includes a second optical sheet bonded to the optical sheet,
At least one of the surface of the optical sheet facing the second optical sheet and the surface of the second optical sheet facing the optical sheet is formed as a surface having irregularities,
The one surface of the surface of the optical sheet that faces the second optical sheet and the surface of the second optical sheet that faces the optical sheet passes through at least a convex portion of the unevenness that forms the surface. In addition, a gap may be formed between the optical sheet and the second optical sheet by bonding to the other surface.

  In the optical member according to the present invention, the optical sheet has a sheet-like main body portion and a plurality of unit optical elements arranged on the main body portion, and the second optical sheet is a sheet-like main body portion. And a plurality of unit optical elements arranged on the main body, and an arrangement direction of the plurality of unit optical elements of the optical sheet, and an arrangement direction of the plurality of unit optical elements of the second optical sheet, May intersect.

In the optical member according to the present invention, the optical sheet includes a sheet-like main body portion and a plurality of unit optical elements arranged on the main body portion, each extending linearly in a direction intersecting the arrangement orientation. A plurality of unit optical elements, and
The second optical sheet includes a sheet-like main body and a plurality of unit optical elements arranged on the main body, each extending linearly in a direction intersecting the arrangement orientation. And having elements
The arrangement direction of the plurality of unit optical elements of the optical sheet may intersect with the arrangement direction of the plurality of unit optical elements of the second optical sheet.

  In the optical member according to the present invention, in an arbitrary cross section along the normal direction of the optical member, the proportion of the length where the polarizing plate and the optical sheet are joined is in the range of 1% to 80%. There may be.

The liquid crystal display panel according to the present invention comprises:
Any of the optical members according to the invention described above;
A liquid crystal cell bonded to the optical member.

  The display device according to the present invention includes any one of the liquid crystal display panels according to the present invention.

  The display device according to the present invention may further include a light emitter provided at a position facing the optical member of the liquid crystal display panel.

  The display device according to the present invention may further include a light guide plate provided at a position facing the optical member of the liquid crystal display panel.

The first optical module according to the present invention comprises:
Any of the optical members according to the invention described above;
A light emitter provided at a position facing the optical member.

The first optical module according to the present invention comprises:
Any of the optical members according to the invention described above;
A light guide plate provided at a position facing the optical member.

  According to the present invention, the traveling direction of light can be changed by an optical member including a polarizer. For this reason, when this optical member is used, the freedom degree of design about the brightness | luminance characteristic and viewing angle characteristic of a display apparatus can be improved significantly.

FIG. 1 is a perspective view illustrating a schematic configuration of a display device, a liquid crystal display panel, an optical module, and an optical member for explaining an embodiment according to the present invention. FIG. 2 is a view for explaining the operation of the display device, and is a view showing the display device in a section taken along line II-II in FIG. 1. FIG. 3 is an enlarged longitudinal sectional view showing a polarizing plate of the optical member of FIG. 4 is a perspective view showing an optical sheet of the optical member of FIG. FIG. 5 is a diagram for explaining an example of a manufacturing method and a manufacturing apparatus for a protective film for a polarizing plate and an optical sheet. FIG. 6 is a diagram corresponding to FIG. 1 and is a diagram for explaining a modification of the light emitter of the light source. FIG. 7 is a view showing a polarizing plate in the same cross section as FIG. 3, and is a view for explaining a modified example of the protective film. FIG. 8 is a view showing the polarizing plate in the same cross section as FIG. 3, and is a view for explaining a modified example of the polarizing plate. FIG. 9 is a view showing the polarizing plate in the same cross section as FIG. 3, and is a view for explaining another modified example of the polarizing plate. FIG. 10 is a diagram illustrating the optical sheet in the same cross section as FIG. 2, and is a diagram for describing a modification of the optical sheet. FIG. 11 is a diagram showing the optical sheet in the same cross section as FIG. 2, and is a diagram for explaining another modified example of the optical sheet. FIG. 12 is a diagram showing the optical sheet in the same cross section as FIG. 2, and is a diagram for explaining still another modified example of the optical sheet. FIG. 13 is a view showing the optical sheet in the same cross section as FIG. 2, and is a view for explaining still another modified example of the optical sheet. FIG. 14 is a diagram showing the optical sheet in the same cross section as FIG. 2, and is a diagram for explaining still another modified example of the optical sheet. FIG. 15 is a view corresponding to FIG. 1 and showing a modification of the optical member. 16 is a view showing a cross section taken along the line IVI-IVI of FIG. FIG. 17 is a view corresponding to FIG. 1 and showing another modification of the optical member. FIG. 18 is a view corresponding to FIG. 1 and showing still another modification of the optical member. FIG. 19 is a view corresponding to FIG. 1 and showing still another modified example of the optical member. FIG. 20 is a perspective view showing the optical member, and is a view for explaining a modification of the light diffusion function in the optical member. FIG. 21 is a longitudinal sectional view showing the display device, and is a diagram for explaining a modification of the display device and the optical module. FIG. 22 corresponds to FIG. 1 and is a perspective view showing a conventional display device. FIG. 23 is a cross-sectional view corresponding to FIG. 21 and showing a conventional display device.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual ones.

  1 to 5 are diagrams for explaining an embodiment according to the present invention. Among these, FIG. 1 is a perspective view showing a schematic configuration of a display device, a liquid crystal display panel, an optical module, and an optical member. FIG. 2 is a view showing a cross section taken along line II-II in FIG. FIG. 3 is an enlarged view showing a polarizing plate of the optical member in a cross section along the front direction, and FIG. 4 is a perspective view showing an optical sheet of the optical member. FIG. 5 is a diagram illustrating an example of a method for producing a protective film for a polarizing plate and an optical sheet.

  A display device 10 shown in FIG. 1 is a liquid crystal display device, and includes a liquid crystal display panel 15, a light source 25 disposed on the back side of the liquid crystal display panel 15 (the side opposite to the observer side), and a light source 25. And a reflection plate 21 that covers from the back side. The light source 25 includes a plurality of light emitters 26 and illuminates the liquid crystal display panel 15 from the back side. On the other hand, the liquid crystal display panel 15 functions as a shutter that controls transmission or blocking of light emitted from the light emitter 26 of the light source 25 for each pixel, and forms an image.

  As will be described in detail later, the liquid crystal display panel 15 includes a liquid crystal cell 11, a polarizing plate 12 disposed on the light output side of the liquid crystal cell 11, and an optical member 18 disposed on the light incident side of the liquid crystal cell 11. Have. Among these, the optical module 20 is formed by the optical member 18 of the liquid crystal display panel 15 and the light emitter 26 forming the light source 25. A polarizing plate 40 is incorporated in the optical member 18, and as a result, the liquid crystal cell 11 is disposed between the pair of polarizing plates 12 and 40. In the following, in order to distinguish a pair of polarizing plates included in the liquid crystal display panel 15, the light incident side polarizing plate 40 is referred to as a lower polarizing plate regardless of the arrangement state of the display device 10, and the light emitting side polarized light. The plate 12 is called an upper polarizing plate.

  The display device 10 is configured as a direct liquid crystal display device. In particular, in the illustrated example of the display device 10, the light emitter 26 constituting the light source 25 is disposed at a position facing the liquid crystal display panel 15 in the front direction nd. That is, the light emitter 26 that constitutes the light source 25 is disposed at a position facing the optical member 18 located on the most incident light side of the liquid crystal display panel 15 and the front direction nd. Therefore, no other member is interposed between the light emitter 26 forming the light source 25 and the lower polarizing plate 40 located on the most incident light side of the liquid crystal display panel 15, and the light emitter 26 emits light. The light can enter the lower polarizing plate 40 directly.

  Various known light emitters such as cold cathode fluorescent lamps and EL light emitters can be used as the light emitter 26 forming the light source 25. However, in the illustrated example, the light source 25 is configured by a plurality of light emitting diodes (LEDs) 26. As can be understood from FIG. 1, the multiple light emitters 26 are two-dimensionally arranged on a virtual plane. That is, a large number of light emitters 26 are not arranged in only one direction on the virtual plane but are arranged with a planar spread. In particular, in the example shown in FIG. 1, the light emitters 26 forming the light source 25 are arranged in the first arrangement direction d1 and also arranged in the second arrangement direction d2 orthogonal to the first arrangement direction. Arranged.

  The reflecting plate 21 is a member for directing light emitted from the light emitter 26 of the light source 25 toward the liquid crystal display panel 15. At least the inner surface of the reflecting plate 21 is made of a material having a high reflectance such as metal.

  In the present specification, the “light exit side” refers to the downstream side in the traveling direction of light from the light emitter 26 of the light source 25 to the observer through the liquid crystal display panel 15 without wrapping the traveling direction (observer side, In FIG. 1, the “light-incident side” is the direction in which the light travels from the light emitter 26 of the light source 25 to the viewer through the liquid crystal display panel 15 without being folded back. It is upstream.

  Further, in the present specification, the terms “sheet”, “film”, and “plate” are not distinguished from each other only based on the difference in names. Therefore, for example, a “sheet” is a concept including a member that can also be called a film or a plate. As a specific example, the “protective film” includes a member called “protective sheet”, and the “optical sheet” also includes a member called “optical film”.

  Further, in the present specification, the “sheet surface (film surface, plate surface)” refers to the planar direction of the target sheet-like member when the target sheet-like member is viewed overall and globally. Refers to the matching surface. And in this Embodiment, the panel surface of the liquid crystal display panel 15, the sheet surface of the sheet-like optical member 18, the plate surface of the polarizing plate 40 of the optical member 18, the film surface of the protective film 50 of the polarizing plate 40 mentioned later The sheet surface of the optical sheet 60 of the optical member 18, the sheet surface of a main body portion 65 of the optical sheet 60 described later, and the like are parallel to each other. Further, in this specification, the “front direction” refers to a direction parallel to the normal direction nd to the display surface 10a of the display device 10, and in the present embodiment, the sheet-like optical member 18 It is parallel to the normal direction to the sheet surface.

  Furthermore, terms used in the present specification that specify shapes and geometric conditions, for example, terms such as “parallel”, “orthogonal”, “symmetric”, “triangle”, and the like are not restricted to a strict meaning. Therefore, it should be interpreted including an error to the extent that a similar optical function can be expected.

  Next, the liquid crystal display panel 15 will be described. As described above, the liquid crystal display panel 15 includes the upper polarizing plate 12, the optical member 18 including the lower polarizing plate 40, and the liquid crystal cell 11 disposed between the pair of polarizing plates 12 and 40. . Among these, the polarizing plates 12 and 40 have a function (absorption type polarization separation function) of decomposing incident light into orthogonal polarization components, transmitting one polarization component, and absorbing the other polarization component. Yes.

  On the other hand, the liquid crystal cell 11 has a pair of transparent substrates and a liquid crystal layer provided between the transparent substrates. An electric field can be applied to the liquid crystal layer for each region where one pixel is formed. Then, the alignment of the liquid crystal layer applied with an electric field changes. For example, the polarization component in a specific direction (direction parallel to the transmission axis) transmitted through the lower polarizing plate 40 disposed on the light incident side passes through a region of the liquid crystal layer to which an electric field is applied in the liquid crystal cell 11. At that time, the polarization direction is rotated by 90 °, and the polarization direction is maintained when passing through the liquid crystal layer to which no electric field is applied. For this reason, depending on whether or not an electric field is applied to each region of the liquid crystal layer, whether the polarization component in a specific direction transmitted through the lower polarizing plate 40 is further transmitted through the upper polarizing plate 12 disposed on the light output side of the lower polarizing plate 40. Alternatively, it is possible to control whether the light is absorbed and blocked by the upper polarizing plate 12. In the liquid crystal display panel 15 described here, the upper polarizing plate 12 and the liquid crystal cell 11 can be configured in the same manner as known members.

  Next, the optical member 18 will be described in more detail. As shown in FIGS. 1 and 2, the optical member 18 includes a polarizing plate (lower polarizing plate) 40 and an optical sheet 60 disposed so as to face the polarizing plate. The polarizing plate 40 and the optical sheet 60 are bonded to each other. An optical element in which at least one of the surface of the polarizing plate 40 facing the optical sheet 60 (light-incident surface side 40b) and the surface of the optical sheet 60 facing the polarizing plate 40 (light-emitting side surface 60a) has irregularities. It is formed as a surface. The optical element surface having the one unevenness is bonded to the other surface via at least a part of the unevenness forming the surface. As a result, a gap V is formed between the polarizing plate 40 and the optical sheet 60 as shown in FIG.

  First, the lower polarizing plate 40 will be described mainly with reference to FIG. The lower polarizing plate 40 includes a polarizer 41 that can exhibit an absorption polarization separation function, and a protective film 50 bonded to the polarizer 41. As shown in FIG. 3, the protective film 50 is laminated on the polarizer 41 from the side that does not face the liquid crystal cell 11, in other words, from the light incident side, and protects the polarizer 41 from the outside.

  Further, an adhesive layer (not shown) is provided between the polarizer 41 and the protective film 50 so as to be adjacent to the polarizer 41 and the protective film 50 and adheres the polarizer 41 and the protective film 50 to each other. It may be. The adhesive layer for improving the adhesion between the polarizer 41 and the protective film 50 can be formed using various conventional adhesives. As one specific example, for example, an adhesive layer can be formed using an aqueous adhesive mainly composed of a polyvinyl alcohol-based resin. In addition, the adhesion in this specification is a concept including adhesion and gluing, and similarly, the adhesive (adhesion layer) in this specification is a concept including pressure-sensitive adhesive (adhesion layer) and glue (gluing layer). is there.

  Various polarizers have been developed to date, and any of these polarizers can be used as the polarizer 41. As a specific example, a polarizer 41 having a polyvinyl alcohol film as a base material can be used. The polarizer 41 based on a polyvinyl alcohol film is anisotropic in absorbing light by adsorbing or dyeing a dichroic dye such as iodine or dye on the polyvinyl alcohol film, and then orienting it by uniaxial stretching. Can be imparted to the polyvinyl alcohol film.

  Next, the protective film 50 will be described. As well shown in FIG. 3, the protective film 50 has a main part 59a made of a resin material and a diffusion component 59b dispersed in the main part 59a. As the resin material forming the main portion 59a, triacetyl cellulose, cyclic polyolefin, acrylic resin, polycarbonate resin, or the like having excellent optical characteristics can be used. For example, a polycarbonate-based resin is suitable as a material used for the lower polarizing plate 40 from the viewpoint of low retardation.

  On the other hand, the diffusing component 59b can be composed of a granular material having a refractive index different from that of the main portion 59a, or a granular material having reflectivity by itself. The particulate material forming the diffusion component 59b may be a metal compound, a porous material containing a gas, or may be a simple bubble. Further, the shape of the diffusion component 59b made of a granular material is not particularly limited. Therefore, the diffusion component 59b does not have to be spherical (particulate) as in the illustrated example, and can have various shapes such as a spheroid shape and a linear shape.

  Thus, due to the diffusion component 59b dispersed in the main portion 59a, the protective film 50 can exhibit a diffusion function for diffusing light. The degree of the light diffusing function of the protective film 50 due to the internally added diffusion component 59b is as follows. The resin material forming the main portion 59a, the thickness of the main portion 59a, the configuration (shape, size (grain) of the diffusion component 59b (Diameter), refractive index, etc.), the concentration of the diffusing component 59b, and the like can be set within an extremely wide range by appropriately setting. Specifically, the haze value of the protective film 50 is set to a level that cannot normally be reached by simply matting (roughening) the surface layer portion, for example, within a range of 60% to 90%. It is also possible to do.

  Moreover, as shown in FIG. 3, the light emission side surface 50a which comes to face the polarizer 41 of the protective film 50 is formed as a flat surface. Thereby, it becomes possible to laminate | stack and adhere | attach the protective film 50 and the polarizer 41 stably, preventing mixing of air etc. On the other hand, in the present embodiment, the light incident side surface 50b opposite to the side facing the polarizer 41 of the protective film 50 is formed as an uneven surface. The unevenness provided on the light incident side surface 50b is caused by the diffusion component 59b dispersed in the main portion 59a. More specifically, the diffusion component 59b is exposed or the outline of the diffusion component 59b is raised. Is formed.

  The light incident side surface 50 b of the protective film 50 not only forms the light incident side surface of the lower polarizing plate 40, but also forms the light incident side surface 40 b of the polarizing plate 40 and the light incident side surface of the liquid crystal display panel 15. For this reason, the protective film 50 according to the present embodiment also exhibits a diffusion function due to not only the diffusion component 59b dispersed in the main portion 59a described above but also the unevenness of the light incident side surface 50b. .

  In this specification, “flat” is used in the opposite meaning of “uneven surface (surface having unevenness)”, and stable lamination and adhesion between the protective film 50 and the polarizer 41 can be secured. Refers to flatness. For example, when the surface roughness of the surface 50a facing the polarizer 41 of the protective film 50 is measured as a ten-point average roughness Rz in accordance with JIS B0601 (1982), it may be 1.0 μm or less. It can be said that it is flat.

  Although the protective film 50 is internally added with the diffusing component 59b, the light-exiting side surface 40a of the protective film 50 is flat, so that the protective film 50 and the polarizer 41 are attached by so-called “water sticking”. Can be laminated and glued. Specifically, the protective film 50 and the polarizer 41 are overlapped with each other with an aqueous solution (or suspension) mixed with water or a suitable additive such as a surfactant interposed therebetween. To go. Thereby, the protective film 50 and the polarizer 41 can be laminated | stacked, preventing mixing of foreign materials, such as air. At this time, an adhesive (for example, glue) is mixed with water or an aqueous solution (or suspension), or an adhesive layer is provided in advance on at least one of the protective film 50 and the polarizer 41, The protective film 50 and the polarizer 41 may be positively bonded.

In addition, in order to accelerate | stimulate the removal of the water | moisture content from the protective film 50 and the polarizer 41 after "water sticking", the water vapor transmission rate of the protective film 50 is 10 g / m under the condition of temperature 40 degreeC and humidity 90% RH. It is preferably ² · 24 hours or more. However, if the moisture permeability is too high, warping or bending due to moisture absorption may occur. Therefore, the moisture permeability is preferably 400 g / m ² · 24 hr or less as measured at a temperature of 40 ° C. and a humidity of 90% RH. . In addition, the moisture permeability in this specification refers to the numerical value measured using the cup method based on JISZ0208.

  Next, the optical sheet 60 laminated on the polarizing plate will be described. The optical sheet 60 described here has a light control function for changing the traveling direction of light. As a specific configuration, the light exit side surface 60a facing the polarizing plate 40 of the optical sheet 60 is formed by unit optical elements (unit prisms) 70 arranged side by side as well shown in FIGS. It is configured as an optical element surface (prism surface) having unevenness. With this optical element surface, the optical sheet 60 exhibits a light collecting function and a light diffusing function (function to make the in-plane distribution of brightness uniform). Further, the optical sheet 60 includes a diffusion component 69b dispersed in a binder resin, and the optical sheet 60 exhibits a light diffusion function (function to make the in-plane distribution of brightness uniform) by the diffusion component 69b. It is supposed to be. Hereinafter, the configuration of the optical sheet 60 will be further described in detail.

  The “unit optical element” in the present specification refers to an element having a function of changing the traveling direction of the light by exerting an optical action such as refraction or reflection on the light. ”,“ Unit prism ”, and“ unit lens ”are not distinguished based only on the difference in designation and elements. Similarly, “prism” and “lens” are not distinguished from each other based solely on the difference in designation.

  2 and 3, the optical sheet 60 is composed of a sheet-like main body 65 and unit optical elements arranged side by side in a predetermined direction (arrangement direction) on the light emission side surface 65a of the main body 65. And an element 70. Each unit optical element 70 extends in a direction intersecting with the arrangement direction and parallel to the sheet surface of the optical sheet 60. In the present embodiment, when observed from a direction parallel to the normal direction to the sheet surface of the sheet-like optical member 18, the arrangement direction of the unit optical elements 70 is the first arrangement direction d1 of the plurality of light emitters 26. (See FIG. 1).

  By the way, the liquid crystal display panel 15 includes a large number of pixels. The liquid crystal display panel 15 forms an image by controlling transmission and blocking of light for each pixel. When the unit optical element 70 is observed from a direction parallel to the normal direction to the sheet surface of the sheet-like optical member 18, the unit optical element 70 intersects the pixel arrangement direction of the liquid crystal cell 11 of the liquid crystal display panel 15. In other words, it is preferably inclined or orthogonal to the pixel arrangement direction. Specifically, when observed from a direction parallel to the normal direction to the sheet surface of the sheet-like optical member 18, the arrangement direction of the unit optical elements 70 and the arrangement direction of the pixels of the liquid crystal cell 11 are 1 °. It is preferably inclined at an angle of not less than 45 ° and more preferably at an angle of not less than 5 ° and not more than 30 °. In this case, moire (interference fringes) caused by interference between the periodicity caused by the regular arrangement of the pixels and the periodicity caused by the regular arrangement of the unit optical elements 70 can be effectively made inconspicuous. it can. From the viewpoint of making the moire inconspicuous, the arrangement pitch of the unit optical elements 70 is preferably 30 μm or less.

  As can be understood from FIGS. 2 and 4, in the present embodiment, the multiple unit optical elements 70 included in the optical sheet 60 are configured identically to each other.

  Here, the cross section shown in FIG. 2 is a cross section along both the arrangement direction of the unit optical elements 70 and the normal direction to the sheet surface of the optical sheet 60 (hereinafter simply referred to as “main cutting surface of the optical sheet”). Also called). In the present embodiment, as shown in FIG. 2, the cross-sectional shape of each unit optical element 70 is a triangular shape on the main cut surface of the optical sheet. In particular, in the illustrated example, the cross-sectional shape of the main cutting surface of the unit optical element 70 is an isosceles triangle that is arranged symmetrically about the normal direction to the sheet surface of the optical sheet 60.

  As an example, the specific dimensions of the illustrated unit optical element 70 can be designed as follows. The arrangement pitch Pa (see FIG. 2) of the unit optical elements 70 on the light exit side surface 65a of the main body 65 can be set to 15 μm or more and 300 μm or less. The protrusion height Ha (see FIG. 2) of the unit optical element 70 from the main body 65 along the normal direction nd to the sheet surface of the optical sheet 60 can be set to 10 μm or more and 200 μm or less. In addition, the apex angle θa (see FIG. 2) of the isosceles triangle shape can be set to, for example, 60 ° or more and 120 ° or less in consideration of the light collecting function. Also,

  Incidentally, as described above, the optical sheet 60 has the diffusion component 69b, and the optical sheet 60 exhibits a light diffusion function by the diffusion component 69b. More precisely, the optical sheet 60 includes a light diffusion layer 61a having a main part 69a made of resin and a diffusion component 69b dispersed in the main part 69a.

  The optical sheet 60 in the present embodiment includes a light diffusion layer 61a and a resin layer 61b that does not contain the diffusion component 69b, as well shown in FIG. In the illustrated example, the resin layer 61b is disposed on the light output side with respect to the light diffusion layer 61a. That is, the resin layer 61b is disposed closer to the polarizer 41 than the light diffusion layer 61a.

  The resin layer 61 b constitutes the unit optical element 70 described above and the light output side portion of the main body 65 adjacent to the unit optical element 70. On the other hand, the light diffusion layer 61a constitutes a light incident side portion of the main body 65 adjacent to the resin layer 61b. Further, due to a manufacturing method described later, there is no optical interface between the main portion 69a of the light diffusion layer 61a and the resin layer 61b. That is, light enters the optical sheet 60 from the light diffusion layer 61a to the resin layer 61b without being optically affected.

  As the resin material forming the resin layer 61b and the resin material forming the main portion 69a of the light diffusing layer 61a, various resin materials having excellent optical characteristics, for example, triacetyl cellulose, cyclic polyolefin, acrylic resin, polycarbonate resin, etc. Can be used. For example, a polycarbonate-based resin is suitable as a material used for the lower polarizing plate 40 from the viewpoint of low retardation.

  On the other hand, the diffusing component 69b dispersed in the light diffusing layer 61a can be composed of a granular material having a refractive index different from that of the main portion 69a, or a granular material having its own reflectivity. Specifically, the same material as the diffusion component 59b of the protective film 50 of the lower polarizing plate 40 described above can be used as the diffusion component 69b contained in the optical sheet 60. That is, the granular material forming the diffusion component 69b of the optical sheet 60 may be a metal compound, a porous material containing gas, or may be a simple bubble. Further, the shape of the diffusion component 59b made of a granular material is not particularly limited. Therefore, the diffusion component 59b does not have to be spherical (particulate) as in the illustrated example, and can have various shapes such as a spheroid shape and a linear shape.

  The optical sheet 60 can exhibit a diffusion function of diffusing light due to the light diffusion layer 61a including the diffusion component 69b. The degree of the light diffusing function of the optical sheet 60 due to the internally added diffusion component 69b is as follows. The resin material forming the main portion 69a, the thickness of the main portion 69a, the configuration (shape, size (grain) of the diffusion component 69b (Diameter), refractive index, etc.), the concentration of the diffusing component 69b, and the like can be adjusted within an extremely wide range by appropriately setting. Specifically, the haze value of the optical sheet 60 is set to such a degree that it cannot normally be reached by simply matting (roughening) the surface layer portion, for example, within a range of 60% to 90%. It is also possible to do.

  The optical sheet 60 having the above configuration is bonded to the polarizing plate 40 disposed on the light output side via an adhesive 55. As well shown in FIG. 2, the adhesive 55 is provided only in a region near the top 71 of the unit optical element 70 closest to the polarizing plate 40. In the present embodiment, since the unit optical elements 70 are arranged in parallel on the main body 65, the adhesive 55 can be provided in a striped manner between the optical sheet 60 and the polarizing plate 40. The application of the adhesive 55 onto the optical sheet 60 can be performed using various known coating apparatuses, for example, a gravure coater. By using such an adhesive 55, the optical sheet 60 is bonded to the polarizing plate 40 only in the area near the top 71 of the unit optical element 70.

  That is, the light output side surface 60a of the optical sheet 60 and the light incident side surface 50b of the protective film 50 of the polarizing plate 40 formed by the unit optical elements 70 arranged without gaps are coated with the adhesive 55 only in a part of the region. Has been. As a result, at least a part of the light exit surface (prism surface) of the unit optical element 70 is exposed to the gap V formed between the optical sheet 60 and the polarizing plate 40 without being covered with the adhesive 55. Thereby, the optical function at the light exit surface (prism surface) of the unit optical function is ensured, and a desired optical action can be exerted on the light emitted from the optical sheet and traveling toward the polarizing plate 40.

  Similarly, the light incident side surface 50b having the unevenness of the protective film 50 that forms the light incident side surface 40b of the lower polarizing plate 40 is also not covered with the adhesive 55 in at least a part of the area, and the optical sheet 60 and the polarizing plate. 40 is exposed to the gap V formed between the two. Thereby, the optical function (light diffusion function) resulting from the unevenness on the light incident side surface of the protective film 50 is ensured, and a desired optical action may be exerted on the light incident on the polarizing plate 40 through the protective film 50. it can.

  Further, in conventional display devices and surface light source devices, a phenomenon has occurred in which two adjacent optical sheets are deformed, for example, due to changes in environmental conditions, and contact with each other or even rub against each other. The irregularly deformed optical sheet can no longer exhibit the expected optical function. Further, the contact or rubbing between the two optical sheets may be visually recognized, and in this case, the image quality displayed on the display device is deteriorated. In particular, when two optical sheets are rubbed with each other, the rubbed part is easily visually recognized, and further, scraped scraps may be generated. On the other hand, according to the present embodiment, the optical sheet 60 is bonded to the polarizing plate 40 laminated on the relatively rigid liquid crystal cell 11 via the adhesive 55, and the liquid crystal cell 11 and the polarizing plate are bonded. 40. Therefore, even if the optical sheet 60 receives a large amount of heat from the light emitter 26 constituting the light source 25, for example, the deformation is constrained by the polarizing plate 40 and the liquid crystal cell 11. As a result, the optical sheet 60 can continue to exhibit the expected optical function, and deterioration of image quality caused by the contact between two adjacent optical sheets, which has conventionally occurred, can be prevented.

  In addition, when this inventor repeated earnest research, in the arbitrary cross sections along the normal line direction of the optical member 18, the ratio (bonding ratio) which the length which the polarizing plate 40 and the optical sheet 60 are joined is occupied. ) Is in the range of 1% or more and 80% or less, that is, when applied to the present embodiment, the adhesive 55 is applied in any cross section along the normal direction to the sheet surface of the sheet-like optical member 18. It is preferable that the ratio (hereinafter referred to as a joining ratio) occupied by the length lj (see FIG. 2) bonded via the metal is in the range of 2% to 50%. In this case, the optical function surface is effectively exhibited by the optical element surface having the unevenness exposed in the gap, and the optical sheet 60 and the protective film 40 can be stably bonded. In specifying the joining ratio in the optical member 18, for example, a range of the optical member 18 observed with a microscope, the configuration of the surface facing the optical sheet 60 of the polarizing plate 40 (protective film 50), and the optical properties. In consideration of the configuration of the surface of the sheet 60 facing the polarizing plate 40 (protective film 50), a range having a length expected to reflect the entire bonding ratio (for example, configured in the above dimension example) In the optical member 18 including the optical sheet 60, the joining ratio for a range of 10 mm in length may be calculated, and the calculated value may be handled as the joining ratio of the optical member 18. Moreover, in specifying the bonding ratio, it is necessary to specify the region where the polarizing plate 40 (protective film 50) and the optical sheet 60 are bonded. This region is the same as the polarizing plate 40 (protective film 50). The region where the optical sheet 60 is in optical contact is specified. That is, the region where the polarizing plate 40 (protective film 50) and the optical sheet 60 are bonded in specifying the bonding ratio is a region where no gap V that can exert an optical action on visible light is formed. Yes, specifically, a region where no gap V is formed between the polarizing plate 40 (protective film 50) and the optical sheet 60, and between the polarizing plate 40 (protective film 50) and the optical sheet 60. Although the air gap V is formed, the length along the normal direction nd of the air gap V is a region that is less than the shortest wavelength of visible light.

  Here, with reference mainly to FIG. 5, an example of the manufacturing method of the protective film 50 which consists of the above structures is demonstrated. In the following description, the optical sheet 60 is formed as an extruded material extruded by an extrusion process.

  First, the extrusion device 80 that can be used for manufacturing the optical sheet 60 will be described. As shown in FIG. 5, the extruding device 80 includes an extruding machine 82 including a die 82 a, a forming roll 84, a backup unit 86 disposed so as to face the forming roll 84, and downstream of the forming roll 84 and the backup unit 86. Guiding means 88 arranged on the side. The guiding means 88 is configured as a pair of guide rolls 88a. In addition, the extrusion device 80 includes a heating unit 83 that heats the molding roll 84 and a cooling unit 87 that cools the molding roll 84.

  The forming roll 84 has a cylindrical outer shape, and in this example, a groove having a shape corresponding to the cross-sectional shape of the unit optical element 70 is spiral on the cylindrical outer peripheral surface of the forming roll 84. It is formed in a large number or in a circumferential shape. The columnar molding roll 84 is rotatable about a rotation axis passing through the center of the column.

  Further, the molding roll 84 has a center portion 85a, a surface layer portion 85c, and a heat insulating portion (heat insulating layer) 85b provided between the center portion 85a and the surface layer portion 85c. The surface layer portion 85c constitutes a molding surface 84a of the molding roll 84, and is formed with a groove having a shape corresponding to the cross-sectional shape of the unit optical element 70 described above. The heat insulating part 85b has higher heat insulating properties than the surface layer part 85c and the central part 85a. In addition, the level of heat insulation can be evaluated using heat conductivity, and it can be said that heat insulation is so high that the value of heat conductivity is small. As an example, the heat insulation part 85b can be formed from super engineering plastics such as polyether ether ketone or ceramics, and the surface layer part 85c and the center part 85a can be made of steel.

  The backup means 86 has two or more support rolls 86a and an edgeless belt member (belt) 86b spanned between the two or more support rolls 86a. In the illustrated example, the backup means 86 has two support rolls 86a. Each support roll 86a is formed in a columnar shape, and is rotatable around a rotation axis passing through the center of the column. The rotation axes of the support rolls 86a are parallel to each other, and are also parallel to the rotation axis of the forming roll 84. And the two or more support rolls 86a can drive the belt member 86b spanned over the said support roll 86a by rotating centering around a rotating shaft line.

  In the illustrated example, one of the two support rolls 86 a is configured as a nip roll 86 a 1 that is disposed to face the molding roll 84. The other of the two support rolls 86a is configured as an adjustment roll 86a2 that establishes a moving path of the belt member 86b with the nip roll 86a1.

  As shown in FIG. 5, the belt member 86 b is deformed between the nip roll 86 a 1 and the adjustment roll 86 a 2 according to the outer contour of the molding roll 84 by pressing from the molding roll 84. For this reason, as will be described later, the film material 90 passing between the belt member 86b and the molding roll 84 is formed by the belt member 86b and the molding roll 84 over a nip section NZ having a certain length along the movement path. It will continue to be pressurized. In the configuration shown in FIG. 5, for example, the length of the nip section NZ can be appropriately adjusted by adjusting the position of the support roll 86a, particularly the adjustment roll 86a2.

  The forming roll 84, the nip roll 86a1, the adjustment roll 86a2, and the belt member 86b are configured using various materials. For example, as the forming roll 84, the nip roll 86a1, and the adjustment roll 86a2, a metal roll, a roll whose center portion is made of metal and whose surface layer portion is made of an elastic body (for example, rubber) can be used. Further, as the belt member 86b, a durable metal-free belt, for example, a belt-shaped member made of a metal alloy such as a chromium alloy or a nickel alloy can be used.

  In addition, it is not restricted to the above example, The backup means 86 may be comprised from the mere metal roll or the rubber roll.

  As shown in FIG. 5, the heating means 83 is located at a position immediately before the backup means 86 of the molding roll 84, that is, a position immediately before contacting the extrusion material (film material) 90 of the molding roll 84. The molding roll 84 can be heated from the molding surface 84a. As the heating means 83, a far-infrared heater 83a can be used as shown in FIG.

  On the other hand, the cooling means 87 is disposed to face the molding roll 84 at a position between the backup means 86 and the adjusting means 88 along the movement path of the extruded material 90. The cooling means 87 can contact the surface layer portion 85c of the molding roll 84 via the extrusion material 90, and can cool the molding roll 84 from the molding surface 84a. As the cooling means 87, a cooling roll 87a in which a circulation path for a refrigerant (for example, cooling water) is formed can be used.

  As described above, the molding roll 84 is provided with the heat insulating portion 85b excellent in heat insulating properties at a position adjacent to the surface layer portion 85c forming the molding surface 84a. Therefore, it is mainly the surface layer portion 85 c of the molding roll 84 that is heated from the heating means 83, and the surface layer portion 85 c of the molding roll 84 is mainly deprived of heat by the cooling means 87. For this reason, by reducing the thickness of the surface layer portion 85c and reducing the heat capacity of the surface layer portion 85c, the temperature of the surface layer portion 85c of the molding roll 84 can be quickly and greatly increased using the heating means 83 and the cooling means 87. It becomes possible to change to. Specifically, the surface layer portion 85c of the molding roll 84 cooled by the cooling means 87 can be heated in a short time by heating from the heating means 83, and conversely, the molding roll heated by the heating means 83. The surface layer portion 85c of 84 can be cooled in a short time by cooling by the cooling means 87.

  Next, a method for manufacturing the above-described optical sheet 60 using such an extrusion device 80 will be described. In the method described here, a film material 90 as an extrusion material including the light diffusion layer 61a and the resin layer 61b described above is manufactured by so-called coextrusion. Then, the obtained film material 90 forms the optical sheet 60.

  First, the first material that forms the light diffusion layer 61a and the second material that forms the resin layer 61b are put into the extruder 82. The first material that forms the light diffusion layer 61a includes a thermoplastic resin that forms the main portion 69a (for example, a pellet-shaped thermoplastic resin material) and a granular material that forms the diffusion component 69b. And are included. Further, the second material that forms the resin layer 61b includes a thermoplastic resin (for example, a pellet-shaped thermoplastic resin material) that forms the resin layer 61b. The thermoplastic resin contained in the second material may be a resin material different from the thermoplastic resin contained in the first material, or may be the same resin material as the thermoplastic resin contained in the first material. May be.

  The thermoplastic resin constituting the first and second resin materials charged into the extruder 82 is heated to the glass transition temperature or higher in the extruder 82. Then, the heated and softened first and second resin materials are extruded by the extruder 82.

  As an example, when a polycarbonate resin having a glass transition temperature of around 140 ° C. is used as the thermoplastic resin contained in the first and second resin materials, the temperature of the thermoplastic resin immediately after passing through the die 82a is You may make it heat a thermoplastic resin in the extruder 82 so that it may become about 300 degreeC. Further, when the optical sheet 60 is produced by extrusion processing, the average particle diameter of the granular material that forms the diffusion component 69b (the particle diameter calculated by the volume equivalent method, that is, the arithmetic average of the volume equivalent diameter, the same applies hereinafter). The content of the granular material that forms the diffusion component 69b may be more than 0% by weight and 40% by weight or less.

  In this way, the first layer (the layer that forms the light diffusing layer 61a) having the thermoplastic resin and the diffusion component dispersed in the thermoplastic resin, and the second layer made of the thermoplastic resin. A film material 90 having (a layer that forms the resin layer 61b) is formed as an extrusion material. At this time, in the die 82a of the extruder 82, the thickness of the film material 90 can be controlled to a desired thickness.

  The film material 90 extruded from the extruder 82 advances between the forming roll 84 and the backup means 86. At this time, the first layer (the layer that forms the light diffusing layer 61a) having the thermoplastic resin and the diffusion component dispersed in the thermoplastic resin in the film material 90 is the backup means 86. The second layer made of the thermoplastic resin (the layer that forms the resin layer 61 b) comes into contact with the molding roll 84. The film material 90 is supported by the endless belt 86b of the backup means 86 from the side of the first layer (the layer that forms the light diffusion layer 61a) made of a thermoplastic resin and a granular material. 84 is pressed from the side of the second layer made of a thermoplastic resin (the layer that forms the resin layer 61b). The pressing of the film material 90 by the edgeless belt 86b and the molding roll 84 of the backup means 86 is continued while the film material 90 proceeds through the section NZ having a predetermined length.

  In this way, the mold surface 84a of the molding roll 84 is pressed against the layer made of the thermoplastic resin of the film material 90 (the layer that forms the resin layer 61b), and the uneven shape of the molding surface 84a is transferred to the film material 90. Is done. Further, the diffusion component is pushed into the film material 90 while the film material 90 is sandwiched between the forming roll 84 and the edgeless belt 86 b of the backup means 86.

  The edgeless belt 86b has a much smaller heat capacity than the molding roll 84, and is not heated by a heater or the like. Therefore, even if the edgeless belt 86 b absorbs heat from the film material 90, it performs sufficient heat dissipation while not in contact with the film material 90. For this reason, when the edgeless belt 86b comes into contact with the film material 90 again, the temperature of the edgeless belt 86b is sufficiently lowered, and the edgeless belt 86b promotes cooling of the film material 90. As a result, when the film material 90 is separated from the edgeless belt 86b of the backup means 86, the first layer (the light diffusing layer 61a) made of the thermoplastic resin and the particulates that have been in contact with the edgeless belt 86b of the film material 90 is formed. Layer) is sufficiently cooled. That is, the film material 90 can be sufficiently cooled by the edgeless belt 86b so that the thermoplastic resin contained in the layer reaches a temperature lower than the glass transition temperature.

  In addition, when the temperature of the first layer that forms the light diffusion layer 61a is lowered to below the glass transition temperature of the resin material that forms the main portion 69a of the light diffusion layer 61a as described above. The thermoplastic resin material has a certain degree of deformation resistance. For this reason, it becomes difficult to produce the thermal deformation resulting from the difference between the thermal expansion coefficient of the resin material which makes the main part 69a, and the thermal expansion coefficient of the granular material which makes the diffusion component 69b. That is, in the subsequent cooling process, the portion of the resin material that forms the main portion 69a recedes and the contour of the granular material that forms the diffusing component 69b is suppressed from rising, and the film material 90 has no edge. The surface that has been in contact with the belt 86b can be maintained as a flat surface.

  On the other hand, the temperature of the film material 90 immediately after being extruded from the extruder 82 has risen to about 300 ° C. Immediately before the film roll 90 comes into contact with the film material 90, the molding roll 84 is heated from the side of the molding surface 84 a by the heating means 83. The surface layer portion 85c including the molding surface 84a is partitioned from the central portion 85a by the heat insulating portion 85b, and the temperature thereof can be increased rapidly and significantly. At this time, the temperature of the molding surface 84a is equal to or higher than the glass transition temperature of the resin material to be molded by the molding roll 84 of the film material 90, for example, when the molded resin material is polycarbonate. Is heated to about 160 ° C. Thus, the film material 90 immediately after being extruded is pressed by the heated molding surface 84a of the molding roll 84 and the edgeless belt 86b of the backup means 86.

  The film material 90 is pressed between the edgeless belt 86b of the backup unit 86 and the molding roll 84 while traveling through the section NZ having a predetermined length. During this time, as described above, the film material 90 is deprived of heat by the edgeless belt 86 b of the backup means 86, and the film material 90 is also deprived of heat from the forming roll 84. However, as described above, the heat of the film material 90 is rapidly taken away from the edgeless belt 86 b side, but the molding roll 84 is heated immediately before contacting the film material 90. Therefore, the resin to be molded is pressed by the molding surface 84a of the molding roll 84 for a predetermined time in a state where the resin to be molded is maintained at a high temperature, preferably a temperature equal to or higher than the glass transition temperature. . As a result, a desired uneven shape is accurately formed on the film material 90.

  As shown in FIG. 5, the film material 90 released from the pressure between the backup means 86 and the molding roll 84 is supported by the backup means 86 and the guiding means 88 and thereafter the molding roll 84. It is pressed toward the molding surface 84a. The film material 90 disposed on the molding surface 84 a of the molding roll 84 then passes between the molding roll 84 and the cooling roll 87 a that forms the cooling means 87. At this time, the film material 90 is cooled by the cooling means 87 while being pressed toward the molding surface 84a. Therefore, during this cooling, the film material 90 is pressed against the molding surface 84a, so that deformation is restricted. This effectively prevents the shaped uneven shape of the film material 90 (the uneven shape that forms the unit optical element 70) from being greatly deformed from the expected shape due to heat shrinkage. Can do.

  At the same time, the surface layer portion 85c including the molding surface 84a of the molding roll 84 is also cooled by the cooling roll 87a through the film material 90. As a result, the film material 90, together with the surface layer portion 85c of the molding roll 84, is heated to a temperature lower than the glass transition temperature of the resin material forming the film material, for example, 130 when the resin material to be cooled is polycarbonate. It can be stably cooled to about ° C. In this way. Even the temperature of the surface layer portion 85c of the molding roll 84 is cooled to a temperature lower than the glass transition temperature of the resin material forming the film material 90, so that the temperature of the film material 90 again exceeds the glass transition temperature. Accordingly, the shape formed with high accuracy due to the preliminary heating of the molding roll 84 can be maintained as it is.

  The extruded material 90 separated from the molding roll 84 is then cooled by the guiding means 88 and guided while being moderately warped and corrected for warping and bending. As described above, the optical sheet 60 made of the film material (extruded material) 90 formed by extruding the thermoplastic resin material together with the particulates is produced. The flat light incident side surface 60b of the optical sheet 60 is formed by the surface of the film material 90 that is in contact with the backup means 86, and the light output side surface 60a on which the unit optical element 70 of the optical sheet 60 is formed is an extruded material. It is formed by the surface that has been in contact with the 90 molding rolls 84.

  In addition, the protective film 50 of the lower polarizing plate 40 can also be produced by extrusion processing similarly to the optical sheet 60 described here. At this time, a molding roll 84 having a molding surface 84a configured as a flat surface is used as the molding roll of the above-described extrusion processing machine (manufacturing apparatus) 80. In the actual extrusion process, as a single layer extrusion process instead of the coextrusion described above, a thermoplastic resin that forms the main part 59a and a granular material that is dispersed in the thermoplastic resin and forms the diffusion component 59b The film material 90 is extruded from the extruder 82. Further, while maintaining the cooling from the surface of the film material 90 that contacts the backup means 86 to a certain level, the cooling from the surface that contacts the molding roll 84 is weakened. . Thus, the film material 90 is further cooled from the side that has been in contact with the molding roll 84 after being released from the molding roll 84. By the cooling after the release from the molding roll 84, the resin material forming the main portion 59a is thermally contracted, and as a result, the diffusion component 59b can be lifted from the main portion 59a. Thereby, the protective film 50 having the flat light exit side surface 50b made of the surface that has been in contact with the backup means 86 and the light entrance side surface 50a having irregularities made of the surface that has been in contact with the molding roll 84, can get.

  Next, the operation of the display device 10 caused by the optical member 18 will be described with reference mainly to FIG.

  In FIG. 2, the light emitted from the light emitter 26 of the light source 25 travels to the viewer side directly or after being reflected by the reflecting plate 21 and enters the liquid crystal display panel 15. An optical member 18 is provided on the most incident light side of the liquid crystal display panel 15. The light incident side surface 60 b of the optical sheet 60 in the optical member 18 forms the most light incident side surface of the liquid crystal display panel 15.

  As described above, the optical sheet 60 has the light diffusion layer 61a having the diffusion component 69b on the light incident side. Therefore, the light incident on the optical sheet 60 of the optical member 18 is first diffused to a desired degree by the light diffusion layer 61a. Due to the diffusion in the light diffusion layer 61a, it is possible to eliminate unevenness in brightness due to the configuration (array) of the light emitters 26 of the light source 25.

  The light diffused by the light diffusion layer 61a of the optical sheet 60 is then emitted from the light exit side surface 60a of the optical sheet 60 through the resin layer 61b. As described above, the light exit side surface 60 a of the optical sheet 60 is formed by the unit optical element 70, and the light emitted from the light exit side surface 60 a of the optical sheet 60 is refracted by the light exit side surface (prism surface) of the unit optical element 70. Due to this refraction, the traveling direction (outgoing direction) of the light traveling in the direction inclined with respect to the front direction nd is mainly bent so that the angle with respect to the front direction nd is smaller than the traveling direction immediately before refraction. . In this way, the optical sheet 60 exhibits a light collecting function with respect to the light from the light source 25.

  The light collected by the unit optical elements 70 of the optical sheet 60 is a component mainly along the arrangement direction of the linear unit optical elements 70. Then, by appropriately designing the cross-sectional shape of the unit optical element 70, as shown in FIG. 2, the light collecting function of the unit optical element 70 of the optical sheet 60 is two light emitters adjacent in the arrangement direction. 26, which is a region including a position facing the intermediate point 26 and has a tendency that the brightness tends to decrease.

  In other words, the unit optical element 70 not only collects light components along the arrangement direction but also exhibits a function of reducing unevenness in brightness (particularly, the luminance in the front direction) along the arrangement direction. As described above, since the unit optical elements 70 mainly exhibit an optical function with respect to light components parallel to the arrangement direction, the arrangement directions of the unit optical elements 70 as in the examples shown in FIGS. 1 and 2. Is parallel to the arrangement direction of the light emitters 26, the brightness variation along the arrangement direction of the light emitters 26 can be effectively uniformed and made inconspicuous. Therefore, in the example shown in FIG. 1, the first arrangement direction d1 of the light emitters 26 arranged two-dimensionally is parallel to the arrangement direction of the unit optical elements 70. It is possible to eliminate unevenness in brightness along the line and effectively uniformize the in-plane distribution of luminance.

  As described above, the unit optical element 70 of the optical sheet 60 is useful for improving the luminance in the front direction, and uneven brightness (in-plane variation in luminance) due to the configuration (arrangement) of the light emitter 26 of the light source 25. It also helps to ease. In particular, in the present embodiment, the unit optical element 70 is located in the resin layer 61 b, and the diffusion component 69 b is not dispersed in the unit optical element 70. For this reason, the surface (prism surface) of the unit optical element 70 that expresses the optical function can be formed with high accuracy as a flat surface without unevenness caused by the diffusion component 69b. Thereby, the unit optical element 70 of the optical sheet 60 can exhibit the expected desired optical function.

  The degree of such a condensing function by the optical sheet 60 is such that the arrangement pitch pa1 of the two adjacent light emitters 26, the light emitter 26 and the optical sheet 60 along the normal direction to the sheet surface of the optical sheet 60 (optical member). By appropriately setting the separation distance la1 from 18), the shape of the unit optical element 70, the refractive index of the unit optical element 70, etc., it can be adjusted within a very wide range.

  As shown in FIG. 2, the light emitted from the optical sheet 60 via the unit optical element 70 is then incident on the protective film 50. The protective film 50 has a main part 59a and a diffusion component 59b dispersed in the main part 59a, and exhibits a light diffusion function due to the internally added diffusion component 59b. The light diffusing function in the protective film (light diffusing layer) 50 due to such internally added diffusing component 59b is achieved by, for example, forming the surface into a matte surface by molding or providing a granular material on the surface layer portion. Compared with the light diffusing function caused by making the surface of the matte surface, the degree (diffusion strength) and quality (diffusion uniformity) are remarkably excellent.

  Specifically, when the surface is merely matted, light L33 that cannot pass through is generated as shown by a two-dot chain line in FIG. . On the other hand, according to the internally added diffusion component 59b, the diffusion component 59b is dispersed not only in the plane direction but also in the thickness direction. For this reason, the lights L31 and L32 incident on the protective film 50 collide with the diffusing component 59b at least once and change the traveling direction thereof with a high probability. Further, as described above, the resin material forming the main portion 59a, the thickness of the main portion 59a, the configuration (shape, size (particle size), refractive index, etc.) of the diffusing component 59b, the concentration of the diffusing component 59b, etc. are set as appropriate. By doing so, the degree of the light diffusion function of the protective film 50 can be adjusted within an extremely wide range.

  As described above, the light incident on the polarizing plate 40 from the optical sheet 60 in the optical member 18 can be diffused to some extent by the protective film 50. Thereby, the angular distribution of luminance after being condensed by the unit optical element 70 of the optical sheet 60 can be changed smoothly. In addition, by appropriately adjusting the degree of the light diffusing function in the protective film 50, the in-plane distribution of luminance due to the arrangement of the light emitters 26 along the first arrangement direction d1 and the second arrangement direction d2 is effective. It is also possible to more reliably prevent the image (light image) of the light emitter 26 from being visually recognized.

  The light diffused by the protective film 50 of the polarizing plate 40 is then directed to the polarizer 41, the liquid crystal cell 11, and the upper polarizing plate 12 of the lower polarizing plate 40 disposed on the light output side of the protective film 50. At this time, the liquid crystal cell 11 selectively transmits light for each pixel, so that an observer of the display device 10 can observe an image.

  According to the present embodiment as described above, the optical member 15 incorporated in the liquid crystal display panel 15 of the display device 10 is bonded to the polarizing plate (lower polarizing plate) 40 having the polarizer 41 and the polarizing plate 40. And an optical sheet 50. At least one of the surface of the polarizing plate 40 facing the optical sheet 60 and the surface of the optical sheet 60 facing the polarizing plate 40 is formed as an optical element surface having irregularities, and has a desired optical function. Can be granted. In addition, the one optical element surface is bonded to the other surface through at least a part of the unevenness forming the surface, and a gap V is formed between the polarizing plate 40 and the optical sheet 60. Yes. Since the gap V is formed between the polarizing plate 40 and the optical sheet 60 in this way, the optical function on the optical element surface is effectively exhibited, and the traveling direction of the light incident on the liquid crystal display panel 15 is positive. It becomes possible to change to. Thereby, according to the optical member 18 by this Embodiment, the freedom degree of the design about the luminance characteristic and viewing angle characteristic of the display apparatus 10 can be improved markedly. In addition, the optical sheet 60 is bonded to the polarizing plate 40 and, as a result, is supported by the liquid crystal cell 11 having a relatively high rigidity. For this reason, even if environmental conditions (temperature, humidity, etc.) change in the place where the optical member 18 is placed, the deformation of the optical sheet 60 is restrained, and the warp, bend, twist, etc. that occur in the optical sheet 60 Can be prevented from being deformed.

  Further, although depending on the quality required for the display device 10 and the like, since it becomes possible to give a desired light control function to the optical member 18 having the polarizing plate 40, the conventional display device shown in FIG. It is also possible to delete all or part of the optical sheets such as the diffusion plate A, the lower diffusion sheet B, the condensing sheet C, and the upper diffusion sheet D incorporated in the one surface light source device.

  Thus, if even a part of the member (optical sheet) incorporated in the display device can be deleted, the manufacturing cost of the display device can be directly reduced. In addition, it is possible to simplify and omit complicated operations such as positioning of optical sheets required when assembling the display device or the surface light source device. From this point, the manufacturing cost of the display device can be reduced. Can do. Further, by omitting part or all of the members (optical sheets) incorporated in the display device, the display device can be thinned.

  In addition, the optical sheets incorporated in the conventional display device are members for correcting the traveling direction of light, but on the other hand, a part of incident light is absorbed. In addition, in the conventional display device, a lot of light is reflected by any one of the optical sheets, and enters the display panel after returning its traveling direction one or more times. As a result, most of the light emitted from the light emitter 26 serving as the light source 25 is absorbed by any one of the optical sheets and cannot be used for displaying an image. Therefore, the utilization efficiency of light from the light emitter 26 can be improved by reducing the number of members (optical sheets) incorporated in the display device. In particular, according to the illustrated embodiment, the illuminant 26 forming the light source 25 faces the optical protective film 50 including the polarizing plate 40, that is, faces without any intervening member. Therefore, the light emitted from the light emitter 26 can be directly incident on the polarizing plate 40 of the liquid crystal display panel 15, and even if it is reflected, the liquid crystal display panel can be reflected by a single reflection on the reflection plate 21. It can reenter the 15 polarizing plates 40. For this reason, the utilization efficiency of the light emitted by the light emitter 26 can be significantly increased. As a result, for example, it is possible to significantly widen the viewing angle while maintaining the luminance in the front direction without increasing the output of the light source 25 as compared with the conventional display device.

  Furthermore, if all or a part of the optical sheet positioned between the light emitter 26 forming the light source 25 and the liquid crystal display panel 15 (optical member 18) can be reduced, the optical sheet is deformed such as bent, bent, or warped. It is possible to avoid problems such as deterioration in display image quality caused by. In the conventional display device, as shown in FIG. 22, the thickness of the member (diffusion plate A) that faces the light emitter does not deform due to heat generated from the light emitter. It was thick so that the heat transfer toward the member (diffusion sheet or condensing sheet) located on the light exit side could be blocked. Thus, when the thickness of the diffusing plate A increases, the material cost and weight of the diffusing plate A increase, resulting in a problem that the manufacturing cost of the display device increases. Further, when the diffusion plate A having a certain thickness is to be incorporated into the surface light source device, it is necessary to install a corresponding support mechanism. On the other hand, according to the present embodiment described above, the optical member 18 facing the light emitter 26 is laminated on the liquid crystal display panel 15 as an integral member including the polarizing plate 40. That is, since the optical member 18 is directly supported by the liquid crystal display panel 15, a special support mechanism for supporting the optical sheet 60 of the optical member 18 is not necessary, and the liquid crystal display panel 15 deforms the optical sheet 60. Is restrained. Therefore, the configuration of the optical member 18 can be determined from the viewpoint of the optical action expected from the optical member 18 and the protective action of the polarizer, and as a result, the manufacturing cost of the display device 10 can be reduced.

  In the conventional display device 1 shown in FIG. 22, the configurations of the light source 25, the reflecting plate 21, the liquid crystal cell 11, and the upper polarizing plate 12 can be configured in the same manner as in the above-described embodiment.

  Various modifications can be made to the above-described embodiment. Hereinafter, an example of modification will be described with reference to the drawings as appropriate. In the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment are used, and redundant descriptions are omitted.

  In the above-described embodiment, the light emitting body 26 that forms the light source 25 of the display device 10 (the optical module 20) is an example in which the light emitting bodies 26 are two-dimensionally arranged point-like light emitting bodies, typically light emitting diodes. However, the light emitter 26 is not limited to the above-described example, and various known light emitters, for example, a cold cathode tube, an EL (electroluminescent material) that emits light in a planar shape, or the like can also be used. FIG. 6 discloses an example in which a linear cold cathode tube is used as the light emitter 26. The linear cold-cathode tubes forming the light emitters 26 are arranged in a predetermined arrangement direction d1 so as to be parallel to each other. In the example shown in FIG. 6, the arrangement direction d <b> 1 of the linear cold cathode tubes is parallel to the arrangement direction of the unit optical elements 70 of the optical sheet 60 incorporated in the optical member 18. According to this aspect, as already described in the above-described embodiment, the in-plane variation in luminance caused by the arrangement of the cold cathode tubes 26 is alleviated by the unit optical element 70, and the image of the cold cathode tube 26 ( Light image) can be made difficult to see.

  Further, in the above-described embodiment, an example in which the light incident side surface 50b of the protective film 50 of the polarizing plate 40 incorporated in the optical member 18 is provided with unevenness formed due to the presence of the diffusing component 59b, That is, although the example in which the contour of the diffusing component 59b emerges and the unevenness is formed is shown, the present invention is not limited to this. For example, as shown in FIG. 7, unevenness formed by shaping may be provided on the light incident side surface 50 b of the protective film 50. In the manufacturing method of the protective film described above, if the molding roll 84 having a concavo-convex pattern formed on the outer peripheral surface (molding surface 84a) is used, the concavo-convex pattern of the molding roll 84 contacts the molding roll 84 of the film material (extruded material) 90. As a result, irregularities can be formed on the surface of the film material 90 that contacts the molding roll 84 (that is, the light incident side surface 50b of the protective film 50). In addition, when unevenness is formed on the light incident side surface 50b of the protective film 50 by molding, the unevenness due to the presence of the diffusing component 59b may not be formed on the light incident side surface 50b of the protective film 50 (FIG. 7), or unevenness caused by the presence of the diffusion component 59b may be formed in addition to the unevenness caused by shaping.

  Further, when the light exit side surface 60 a of the optical sheet 60 facing the polarizing plate 40 is formed as an optical element surface having irregularities, the light incident side surface 50 b of the protective film 50 that forms the light incident side surface 40 b of the polarizing plate 40 is provided. Alternatively, it may be formed as a flat surface (see FIG. 10 as an example). Furthermore, although the example in which the protective film 50 forming the light incident side surface 40b of the polarizing plate 40 is formed as a layer having the diffusing component 59b has been described, the present invention is not limited thereto. As an example, the protective film 50 may be a simple resin film, for example, a triacetyl cellulose film (TAC film) having a pair of parallel main surfaces.

  Furthermore, in embodiment mentioned above, although the protective film 50 showed the example joined to the polarizer 41 by water sticking, it is not restricted to this. For example, as shown in FIG. 8, an adhesive layer 49 containing an adhesive 49 a and a diffusion component 49 b dispersed in the adhesive 49 a is arranged between the protective film 50 and the polarizer 41. It may be. According to the embodiment shown in FIG. 8, the degree of the light diffusing function by the adhesive layer 49 can be appropriately adjusted independently of the presence or absence of the light diffusing function in the protective film 50 or the degree of the light diffusing function of the protective film 50. it can. Thereby, the degree of the light diffusion function that the lower polarizing plate 40 can exhibit can be designed more freely. In addition, what was illustrated as the diffusion component 59b which can be contained in the protective film 50 can be used similarly for the diffusion component 49b contained in the contact bonding layer 49. FIG. Further, the degree of the light diffusion function by the adhesive layer 49 can be appropriately adjusted by the same method as the degree of the light diffusion function in the protective film 50.

  Furthermore, in the above-described embodiment, the example in which the lower polarizing plate 40 includes the polarizer 41 and the protective film 50 bonded to the polarizer 41 from the light incident side is shown. A protective film made of another film (intermediate film), for example, a TAC film, may also be provided on the light output side of the child 41. In addition, a phase difference plate for compensating for the phase difference of light may be provided between the lower polarizing plate 40 and the liquid crystal cell 11, but in this case, the protective film on the light output side of the lower polarizing plate 40, You may make it also serve as the protective film of the light-incidence side of a phase difference plate.

  In the example shown in FIG. 9, the intermediate film 48 between the protective film 50 and the polarizer 41 has a function of transmitting a specific polarization component and reflecting other polarization components to return to the light source side again. A polarization separation film 48 is provided. That is, by providing the polarization separation film 48, light of a polarization component that can be transmitted through the polarizer 41 can be selectively incident on the polarizer 41, and other light can be returned to the light source side. The light returned to the light source side can be incident again on the polarization separation film 48 with its polarization state changed by subsequent reflection or the like. “DBEF” (registered trademark) available from 3M USA can be used as the polarization separation film 48 that can be useful for improving luminance. In addition to “DBEF”, a high-intensity polarizing sheet “WRPS” available from Shinwha Intertek, Korea, a wire grid polarizer, or the like can be used as the polarizing separation film 48.

  Furthermore, a light diffusion sheet having a light diffusion function may be provided as the intermediate film 48 between the polarizer 41 of the lower polarizing plate 40 and the protective film 50, or a simple resin film, for example, a pair A triacetyl cellulose film (TAC film) having a parallel main surface may be provided.

  Furthermore, in the above-described embodiment, the adhesive 55 is provided in a range that is a part of the light exit side surface 60 a of the optical sheet 60 and a part of the light entrance side surface 40 b of the polarizing plate 40. An example is shown, but the present invention is not limited to this. For example, as shown in FIG. 10, a layer made of an adhesive 55 is formed on either the surface of the polarizing plate 40 facing the optical sheet 60 or the surface of the optical sheet 60 facing the polarizing plate 40. The other of the surface facing the optical sheet 60 and the surface facing the polarizing plate 40 of the optical sheet 60 may partially contact the layer made of the adhesive 55. In the example shown in FIG. 10, the surface of the polarizing plate 40 facing the optical sheet 60 (the light incident side surface 50 b of the protective film 50) is formed as a flat surface, and a layer of the adhesive 55 is formed on the flat surface. ing. The unit optical element 70 of the optical sheet 60 is in contact with the layer of the adhesive 55 formed on the light incident side surface of the polarizing plate 40 only in the region near the top 71. Also in such an example, since the light exit side surface (prism surface, lens surface) of the unit optical element 70 is exposed to the gap V in a region other than the vicinity of the top portion 71, the unit optical element 70 has a desired optical property. Function can be expressed.

  Furthermore, in the above-described embodiment, the optical sheet 60 constituting the optical member 18 includes the main part 69a made of a resin material, the light diffusion layer 61a made of the diffusion component 69b dispersed in the main part 69a, and the diffusion component 69b. And a resin layer 61b made of only a resin material. In other words, the diffusion component 69b is dispersed only in a part of the optical sheet 60. However, for example, as shown in FIG. 10, the diffusion component 69 b may be dispersed throughout the optical sheet 60. In such an example, the optical sheet 60 is composed only of a light diffusion layer 61a having a main part 69a made of a resin material and a diffusion component 69b dispersed in the main part 69a. The optical element 70 is configured as a part of the light diffusion layer 61a. In this case, the degree of the light diffusion function of the optical sheet 60 can be further freely adjusted.

  Further, in the above-described embodiment, the example in which the cross-sectional shape of the main cutting surface of the unit optical element 70 of the optical sheet 60 is a triangular shape has been shown. The cross-sectional shape can be designed in various shapes. For example, the triangular top portion forming the cross-sectional shape of the unit optical element 70 on the main cut surface of the optical sheet 60 may be chamfered. In addition, as shown by a two-dot chain line in FIG. 2, the two sides extending from the triangular main body 65 described above are deformed so as to be curved outwardly on the main cut surface of the optical sheet. Also good.

  Furthermore, as shown in FIG. 10, the unit optical element 70 may have a curved outer contour on the main cut surface of the optical sheet 60. That is, the light output side surface (prism surface, lens surface) of the unit optical element 70 may be configured as a curved surface. As an example of a specific shape, the unit optical element 70 has a shape corresponding to a part of an ellipse (a semi-ellipse as an example) or a part of a circle (a semi-circle as an example) on the main cut surface of the optical sheet 60. You may do it. The optical sheet 60 shown in FIG. 10 can be manufactured using the extrusion device (manufacturing device) 80 already described with reference to FIG. At this time, a molding roll 84 in which grooves having a shape corresponding to the cross-sectional shape of the unit optical element 70 to be manufactured is formed on the molding surface 84a is used. Further, the film material 90 extruded from the extruder 82 becomes a single-layer extrusion material composed only of the layer that forms the light diffusion layer 61a.

  Furthermore, in the above-described embodiment, an example in which the unit optical elements 70 are one-dimensionally arranged on the main body 65, that is, an example in which the linear unit optical elements 70 are arranged in parallel on the main body 65. However, the present invention is not limited to this. The unit optical elements 70 may be two-dimensionally arranged on the main body 65 so as to constitute a so-called fly-eye lens (or microlens). In this example, the unit optical elements 70 may be arranged in a regular arrangement on the main body 65 or may be arranged in an irregular arrangement. When the point-like unit optical elements 70 are two-dimensionally arranged in a regular arrangement on the main body 65, the first arrangement direction of the unit optical elements 70 is the first arrangement direction d1 of the light emitters 26. (See FIG. 1), and the second arrangement direction of the unit optical elements 70 may be parallel to the second arrangement direction d2 of the light emitters 26 (see FIG. 1). The shape of the point-shaped unit optical element 70 constituting the fly-eye lens (or microlens) includes a part of a sphere (for example, a hemisphere), a part of a spheroid (for example, a half spheroid), a cone, Examples include a pyramid such as a polygonal pyramid such as a quadrangular pyramid, and a frustum such as a truncated cone and a polygonal frustum such as a quadrangular pyramid.

  Furthermore, a plurality of linear unit optical elements arranged linearly and a plurality of point unit optical elements arranged two-dimensionally may be provided on the main body 65. In this aspect, when the protruding height of the point-like unit optical element from the main body portion 65 is higher than the protruding height of the linear unit optical element from the main body portion 65, the optical unit passes through the top of the point-like unit optical element. The sheet 60 and the polarizing plate 40 are joined, and the linear unit optical element is kept away from the polarizing plate 40.

  Furthermore, in the above-described embodiment, the example in which the optical sheet 60 is made of the extruded material obtained by the extrusion processing is shown, but the present invention is not limited to this. A protective film manufactured by other manufacturing methods such as injection molding can also be used. Here, in FIGS. 11 to 14, as an example, an example of an optical sheet 60 that can be produced by molding a resin applied on the base film 63, for example, ionizing radiation, into a desired shape is shown. Yes. The optical sheet 60 shown in FIG. 11 can be produced by molding a resin containing the diffusion component 59b on the base film 63. In the optical sheet 60 shown in FIG. 11, the unit optical element 70 that forms the light exit side surface 60a is formed as a part of the light diffusion layer 61a, and the resin portion made of the base film 63 on the light incident side of the light diffusion layer 61a. 61b is provided.

  The optical sheet 60 shown in FIG. 12 can be produced by molding a resin on the base film 63 containing the diffusion component 69b and forming the light diffusion layer 61a. For example, an extruded material can be used as the base film 63 including the diffusion component 69b, and the base film 63 constitutes the light diffusion layer 61a.

  In the example shown in FIG. 13, the unit optical element 70 is formed by molding a resin on the base film 63, but the light incident side surface where the unit optical element 70 of the base film 63 is not formed. A mat layer 64 having an uneven surface is formed on 60b. The mat layer 64 is composed of a diffusion component 69b and a resin material (for example, ionizing radiation resin) that functions as a binder resin, and the light diffusion layer is formed by the resin material as the binder resin functioning as the main portion 69a. 61a is configured. The mat layer 64 can be formed on the base film 63 either before or after the unit optical element 70 is molded.

  In the example shown in FIG. 14, a mat layer 64 made of a diffusion material 69 b and a resin material (main part 69 a) functioning as a binder resin is formed between the base film 63 and the resin material forming the unit optical element 70. Is formed. In the embodiment shown in FIG. 14, the mat layer 64 is formed on the base film 63, and the unit optical element 70 is shaped on the mat layer 64.

  When forming the optical sheet 60 by molding the resin applied on the base film 63, as shown in FIGS. 11 to 14, the resin applied on the base film 63 is In addition to the plurality of unit optical elements 70, a land portion 62 that is disposed between the base film 63 and the unit optical element 70 and covers the base film 63 may be formed. In this case, the land portion 62 constitutes a part of the main body portion 65 of the optical sheet 60.

  Furthermore, in the above-described embodiment, the example in which the unit optical element 70 of the optical sheet 60 is disposed on the light exit side surface 65a of the main body 65 to form the light exit side surface 60a of the optical sheet 60 has been shown. Not limited. As shown in FIGS. 15 and 16, the unit optical element 70 of the optical sheet 60 may be disposed on the light incident side surface 65 b of the main body 65 to form the light incident side surface 60 b of the optical sheet 60. . The unit optical element 70 projecting toward the light incident side is similar to the unit optical element projecting toward the light exit side described in the above-described embodiment, and has a condensing function and a light diffusion function (mainly, the illuminant 26 that forms a light source). The function of alleviating the uneven brightness due to the arrangement of

  In the optical member 18 shown in FIG. 15 and FIG. 16, the light incident side surface 40b of the polarizing plate 40 (light incident side surface 50b of the protective film 50) is formed as a flat surface. A layer of adhesive 55 is laminated. On the other hand, the light exit side surface 60a of the optical sheet 60 (the light exit side surface 65a of the main body 65) is configured as a surface having irregularities. The light exit side surface 60a of the optical sheet 60 is in contact with the layer of the adhesive 55 only at the uneven convex portion. As a result, the optical sheet 60 and the polarizing plate 40 are bonded together while forming a gap V therebetween.

  Further, in the above-described embodiment, the example in which the optical member 18 includes the polarizing plate 40 and one optical sheet 60 bonded to the polarizing plate 40 is shown, but the present invention is not limited thereto. The optical member 18 may further include a second optical sheet 160 disposed on the side of the optical sheet 60 that does not face the polarizing plate 40 and bonded to the optical sheet 60. In this example, at least one of the surface of the optical sheet 60 that faces the second optical sheet 160 and the surface of the second optical sheet 60 that faces the optical sheet 60 is formed as an uneven surface, The one concavo-convex surface of the surface of the sheet 60 that faces the second optical sheet 160 and the surface of the second optical sheet 160 that faces the optical sheet 60 passes through at least a part of the concavo-convex portions forming the concavo-convex surface. Thus, the gap V may be formed between the optical sheet 60 and the second optical sheet 160 by being bonded to the other surface.

  For example, in the example shown in FIG. 17, the second optical sheet 160 is bonded to the optical sheet 60 of the optical member 18 shown in FIGS. The second optical sheet 160 can be configured in the same manner as the optical sheet in the above-described embodiment. That is, the second optical sheet 160 has a main body 165 and a plurality of second unit optical elements 170 provided on the light exit side surface of the main body 165. The plurality of second unit optical elements 170 are arranged in one direction on the main body 165, and each second unit optical element 170 extends linearly in a direction intersecting with the arrangement direction. That is, the light exit side surface of the second optical sheet 160 facing the optical sheet 60 is formed as an optical element surface (uneven surface) formed by the second unit optical element 170. In the example shown in FIG. 17, the second optical sheet 160 is bonded to the light incident side surface 60 b of the optical sheet 60 via the adhesive 155 provided on the top 171 of the second unit optical element 170. ing.

  On the other hand, in the example shown in FIG. 18, the second optical sheet 160 is bonded to the optical sheet 60 of the optical member 18 shown in FIGS. 15 and 16 from the light incident side. The second optical sheet 160 shown in FIG. 18 can be configured similarly to the optical sheet 60 shown in FIGS. 15 and 16. In other words, the second optical sheet 160 has a main body 165 and a plurality of second unit optical elements 170 provided on the light incident side surface of the main body 165. The plurality of second unit optical elements 170 are arranged in one direction on the main body 165, and each second unit optical element 170 extends linearly in a direction intersecting with the arrangement direction. That is, the surface of the second optical sheet 160 that does not face the optical sheet 60 is formed as an optical element surface (uneven surface) formed by the second unit optical element 170. However, the light exit side surface of the second optical sheet 160 shown in FIG. 18 is configured as a flat surface unlike the light exit side surface of the optical sheet 60 shown in FIG. 15 and FIG. In the example shown in FIG. 18, a layer of adhesive 155 is formed on the flat light exit side surface of the second optical sheet 160. In the example shown in FIG. 18, the top 71 of the unit optical element 70 of the optical sheet 60 is in contact with the layer of the planar adhesive 155 laminated on the light output side surface of the second optical sheet 160. . Thereby, the optical sheet 60 and the second optical sheet 160 are joined to each other while forming a gap V therebetween.

  In the example shown in FIGS. 17 and 18, when observed from the normal direction to the sheet surface of the sheet-like optical sheet 18, the arrangement direction of the unit optical elements 70 in the optical sheet 60 and the second optical sheet 160 It intersects with the arrangement direction of the second unit optical elements 170 and is preferably orthogonal. According to such an example, the light condensing function and the light expansion function due to the unit optical elements 70 and 170 can be exhibited with respect to light components along two different directions.

  Further, the first arrangement direction d1 of the light emitters 26 in which one of the arrangement direction of the unit optical elements 70 of the optical sheet 60 and the arrangement direction of the second unit optical elements 170 of the second optical sheet 160 is two-dimensionally arranged (see FIG. 1), and the other may be parallel to the second arrangement direction d2 of the light emitters 26 (see FIG. 1). In this case, both the in-plane variation in brightness along the first arrangement direction d1 of the light emitters 26 arranged two-dimensionally and the in-plane variation in brightness along the second arrangement direction d1 of the light emitters 26 are obtained. Can be effectively inconspicuous.

  Further, in the example illustrated in FIG. 19, the protective film 50 includes a main body portion 265 and a plurality of unit optical elements 270 formed on the light incident side surface of the main body portion 265. The protective film 50 can be configured in the same manner as the second optical sheet 160 shown in FIG. 18, for example. That is, the protective film 50 has a flat light output side surface and a light output side surface as an optical element surface (uneven surface) formed by a plurality of unit optical elements 260 protruding to the light incident side. The protective film 50 is bonded to the polarizer 41 through a flat light output side surface, while the protective film 50 is bonded to the optical sheet 60 through a light output side surface as an optical element surface (uneven surface). . The optical sheet 60 in the example shown in FIG. 19 is formed in the same manner as the second optical sheet 160 shown in FIG. 18 as an example. Further, the protective film 50 and the optical sheet 60 of the polarizing plate 40 shown in FIG. 19 can be bonded to each other in the same manner as the optical sheet 60 and the second optical sheet shown in FIG. Accordingly, the optical member 18 shown in FIG. 19 also has a light collecting function and a light spreading function for light components along two directions, as in the optical member 18 shown in FIGS. It can be demonstrated.

  Furthermore, the light diffusion function in the protective film 50 in the above-described embodiment, the light diffusion function in the light diffusion layer 61a of the optical sheet 60, and the light diffusion function in the adhesive layer 49 shown in FIG. It may be an isotropic light diffusing function or an anisotropic light diffusing function. As an example, FIG. 20 shows an example in which the light diffusion function of the protective film 50 is an anisotropic diffusion function. In the example shown in FIG. 20, the anisotropic light diffusing function is provided in the protective film 50 by disposing the diffusing component 59b having the longitudinal direction ld in the protective film 50 so as to have an orientation in a predetermined direction od. Has been granted. Here, the longitudinal direction of the diffusion component 59b can be specified as the direction in which the target diffusion component 59b has the longest length. Further, “the diffusion component 59b having the longitudinal direction ld has an orientation in the predetermined direction od” means that the angle formed by the longitudinal direction ld of each diffusion component 59b with respect to the predetermined direction od is 0 ° or more and 45 This means that the diffusion component 59b is arranged with directional regularity with reference to the predetermined direction od.

  The protective film 50 shown in FIG. 20 can be manufactured by the above-described extrusion process using a diffusion component 59b having a longitudinal direction as a raw material together with a resin material that forms the main portion 59a. When the diffusion component 59b having the longitudinal direction passes through the die 82a of the extruder 82 together with the resin material, the diffusing component 59b is directed so that the longitudinal direction ld is along the extrusion direction (machine direction) under high pressure. Accordingly, the diffusion component 59b in the extruded film material 90 is dispersed in the protective film 50 so as to have an orientation in a specific direction od. In this case, the orientation direction of the diffusion component 59b is parallel to the longitudinal direction of the linear unit optical elements 70 arranged in parallel.

  As the shape of the diffusing component 59b having the longitudinal direction ld, various shapes such as a plate shape, a granular shape (rice granular shape), a needle shape, a scale shape, and a fine plate shape can be adopted as an example. As a specific example, the average aspect ratio (the average value of the ratio of the length of the diffusion component 59b along the longitudinal direction ld to the length of the diffusion component 59b along the direction orthogonal to the longitudinal direction ld) is And bubbles having an average particle diameter of 1.5 to 50 μm and an average particle diameter of the diffusion component 59b (particle diameter calculated by the volume equivalent method, ie, arithmetic average of volume equivalent diameter, the same shall apply hereinafter) The diffusion component 59b having the longitudinal direction ld can be used. Moreover, the diffusion component 59b which consists of heat resistant organic fibers, such as the diffusion component 59b which consists of organic fibers, for example, an aramid fiber, a wholly aromatic polyester fiber, a polyimide fiber, can also be used. Moreover, the diffusion component 59b which consists of fibrous fillers, such as glass fiber, a silica fiber, an alumina fiber, a zirconia fiber, can also be used for the diffusion component 59b which consists of inorganic fibers, for example. Furthermore, a diffusion component 59b made of a thin plate filler (mica) can also be used. Furthermore, a diffusing component 59b made of an amorphous filler, for example, a diffusing component 59b made of an inorganic white pigment such as silica, calcium carbonate, magnesium hydroxide, clay, talc, or titanium dioxide can be used.

  The diffusion component 59b having the longitudinal direction ld exhibits a stronger light diffusion function in a direction perpendicular to the longitudinal direction than in a direction parallel to the longitudinal direction. Therefore, in the embodiment shown in FIG. 20 in which the diffusion component 59b having the longitudinal direction ld is oriented in a direction parallel to the longitudinal direction of the unit optical element 70 of the optical sheet 60, the light diffusion caused by the protective film 50 The function is more strongly exerted in the direction parallel to the arrangement direction of the unit optical elements 70 of the optical sheet 60 than in the direction parallel to the longitudinal direction of the unit optical elements 70 of the optical sheet 60. That is, in the aspect shown in FIG. 20, the direction in which the light collecting function by the unit optical element 70 of the optical sheet 60 is mainly exhibited matches the direction in which the light diffusion function by the protective sheet 50 is mainly exhibited. For this reason, it is possible to selectively smooth the angular distribution of the luminance within the plane mainly exerting the light collecting action from the unit optical element 70 of the optical sheet 60. As a result, since it is not necessary to diffuse the light incident on the protective film 50 more than necessary, it is possible to minimize the loss of light and to effectively use the light from the light emitter 26 that constitutes the light source 25.

  In particular, as shown in FIG. 6, when the light source 25 is formed by arranging linear cold cathode tubes 26 in parallel, the light emitter 26 can be obtained only by diffusing light along the arrangement direction of the cold cathode tubes 26. Since the unevenness in brightness due to the arrangement of the above can be eliminated, the protective film 50 shown in FIG. 20 can be preferably used.

  However, without being limited to the example shown in FIG. 20, the protective film 50 may have a stronger light diffusion function in a direction intersecting with the arrangement direction of the unit optical elements 70 of the optical sheet 60, for example, in a direction orthogonal thereto. . In this case, in the embodiment shown in FIG. 1, the variation in brightness along the first arrangement direction d1 of the light emitters 26 can be effectively uniformed by the unit optical element 70, and the first The variation in brightness along the two arrangement directions d2 can be effectively uniformed by the anisotropic diffusion function of the protective film 50.

  Also, any other layer having a light diffusing function, such as the light diffusing layer 61a of the optical sheet 60 or the adhesive layer 49 shown in FIG. 8, exhibits anisotropic light diffusing function in any direction. You may make it have a spreading | diffusion function.

  Furthermore, in the above-described embodiment, an example in which the light emitter 26 that forms the light source 25 is disposed immediately below the optical member 180, that is, the optical member 18 including the polarizing plate 40 is applied to the direct-type liquid crystal display device 10. However, the present invention is not limited to this. As shown in FIG. 21, the polarizing plate 40 including the protective film 50 having a light control function may be disposed at a position facing the light guide plate 23 that receives light from the light emitter 26.

  In the example shown in FIG. 21, the optical member 18 including the polarizing plate 40 and the optical sheet 60 bonded to the polarizing plate 40 has a light emitter 26 and a light guide plate 23 that receives light from the light emitter 26. It is used together with the surface light source device 22 and is arranged at a position facing the light guide plate 23 of the surface light source device 22. In this example, the optical module 20 includes the optical member 18 and the light guide plate 23 disposed at a position facing the protective film 50 of the polarizing plate 40. In the example shown in FIG. 21, the liquid crystal display panel 15 including the polarizing plate 40 can be configured similarly to the above-described embodiment.

  In the example shown in FIG. 21, the surface light source device 22 includes a light guide plate 23, a light emitter 26 disposed on the side of the light guide plate 23, and a reflection sheet 21 a disposed on the back surface of the light guide plate 23. It has a so-called edge light type (side light type) backlight. Light from the light emitter 26 of the light source 25 enters the light guide plate 23 from the side surface (incident surface) of the light guide plate 23, and is guided through the light guide plate 23 while being repeatedly reflected between the pair of main surfaces of the light guide plate 23. Proceed along the direction. The light guide plate 23 is provided with light extraction elements (not shown), for example, white dots provided on the back surface of the light guide plate 23 facing the reflection sheet 21a, diffusion components dispersed in the light guide plate 23, and the like. Light traveling in the light guide plate 23 is emitted from the light guide plate 23 toward the observer so that the amount of emitted light is substantially uniform along the light guide direction. At this time, as shown in FIG. 21, a lot of light emitted from the light guide plate 23 is emitted in a direction greatly inclined from the front direction nd.

  With respect to the light guide plate 23, the unit optical elements 70 of the optical sheet 60 of the optical member 18 are arranged so that the arrangement direction thereof is parallel to the light guide direction of the light guide plate 23. Then, the light incident on the liquid crystal display panel 15 (optical member 18) along the direction greatly inclined from the front direction nd is refracted on the light output side surface (prism surface, lens surface) of the unit optical element 70 of the optical sheet 60. The traveling direction is deflected toward the front direction nd. In this way, the optical sheet 60 of the optical member 18 exhibits a light collecting function, and thereafter, the protective film 50 of the polarizing plate 40 of the optical member 18 exhibits a light diffusion function.

  On the other hand, as shown in FIG. 23, a conventional edge light type surface light source device used in combination with a liquid crystal display panel including a conventional lower polarizing plate 13 often has a light output from a light guide plate 23. A condensing sheet (prism sheet, reflection type prism sheet, reverse prism sheet) C was provided on the side. For this reason, the light collecting function of the optical sheet 60 of the optical member 18 is the same as that of the light collecting sheet (prism sheet, reflective prism sheet, reverse prism sheet) C included in the conventional surface light source device shown in FIG. By making it the same as the light collecting function, the light collecting sheet C can be omitted from the surface light source device while maintaining the optical characteristics of the display device 1 as a whole. Similarly, in the conventional surface light source device shown in FIG. 23, the light diffusion sheet D is provided on the light output side of the light collecting sheet C. However, the optical sheet 60 and the polarizing plate 40 of the optical member 18 are protected. When the film 50 contains diffusion components 69b and 59b, respectively, the light diffusion sheet D can be omitted by appropriately adjusting the degree of the light diffusion function caused by the diffusion components 69b and 59b. It becomes. Thereby, also according to the aspect shown in FIG. 23, the same effect as the above-described embodiment can be obtained.

  In the conventional display device 1 shown in FIG. 23, the same reference numerals as those used for the already described configuration are used for the portions that can be configured the same as the already described configuration. Therefore, duplicate explanation is omitted.

  Although several modifications to the above-described embodiment have been described above, a plurality of modifications can be applied in appropriate combination.

  In addition, in comparison with the conventional display device 1 in which a large number of optical sheets are included between the light emitting body 26 or the light guide plate 23 forming the light source 25 and the liquid crystal display panel 15, an embodiment of the present invention is described. Although the advantages of the optical member 18 have been described, such description excludes the use of the optical member 18 according to one embodiment of the present invention in combination with an optical sheet disposed on the light incident side thereof. It is not a thing. In other words, the present invention includes an embodiment in which one or more optical sheets are disposed between the optical member 18 and the light emitter 26 or the light guide plate 23. It is possible to enjoy excellent operational effects.

DESCRIPTION OF SYMBOLS 10 Display apparatus 11 Liquid crystal cell 15 Liquid crystal display panel 18 Optical member 20 Optical module 25 Light source 26 Light-emitting body 40 Polarizing plate, lower polarizing plate 41 Polarizer 48 Intermediate film 49 Adhesive layer 49a Adhesive 49b Diffusion component 50 Protective film, Optical sheet 50a Light exit side surface 50b Light entrance side surface 60 Optical sheet 60a Light exit side surface 60b Light entrance side surface 61a Light diffusion layer 61b Resin layer 62 Land portion 64 Mat layer 65 Main body portion 65a Light exit side surface 65b Light entrance side surface 69a Main portion 69b Diffusing component 70 Unit optical element, Unit shape element, unit prism, unit lens 71 Top portion 160 Optical sheet, second optical sheet 165 Main body portion 165a Light exit side surface 165b Light entrance side surface 169a Main portion 169b Diffusing component 170 Unit optical element, unit shape element, unit prism, unit lens 171 Top 265 Body 270 Unit Optical element 271 Top

Claims (16)

A polarizing plate having a polarizer;
An optical sheet disposed opposite to the polarizing plate and bonded to the polarizing plate,
At least one of the surface of the polarizing plate facing the optical sheet and the surface of the optical sheet facing the polarizing plate is formed as a surface having irregularities,
An optical member in which the one surface is bonded to the other surface through at least a part of the convex portions of the unevenness forming the surface, and a gap is formed between the polarizing plate and the optical sheet. . The polarizing plate further includes a protective film that forms a surface facing the optical sheet,
The optical member according to claim 1, wherein the protective film has a main part made of a resin material and a diffusion component dispersed in the main part.   The optical member according to claim 2, wherein a surface of the protective film facing the optical sheet has at least one of irregularities formed due to the presence of the diffusion component and irregularities formed by shaping. .   The said optical sheet is an optical member as described in any one of Claims 1-3 which has a sheet-like main-body part and the several unit optical element arranged on the said main-body part. The unit optical element of the optical sheet forms a surface facing the polarizing plate of the optical sheet,
The optical member according to claim 4, wherein the optical sheet is bonded to the polarizing plate via a top portion of the unit optical element. The unit optical element is provided on the surface of the main body that does not face the polarizing plate.
The optical member according to claim 4.   The optical member according to claim 6, wherein a surface of the main body portion on which the unit optical element is not provided has irregularities and forms a surface facing the polarizing plate. A second optical sheet disposed on the side of the optical sheet that does not face the polarizing plate and bonded to the optical sheet;
At least one of the surface of the optical sheet facing the second optical sheet and the surface of the second optical sheet facing the optical sheet is formed as a surface having irregularities,
The one surface of the surface of the optical sheet that faces the second optical sheet and the surface of the second optical sheet that faces the optical sheet passes through at least a convex portion of the unevenness that forms the surface. The optical member according to claim 1, wherein the optical member is bonded to the other surface, and a gap is formed between the optical sheet and the second optical sheet. The optical sheet has a sheet-like main body, and a plurality of unit optical elements arranged on the main body,
The second optical sheet has a sheet-like main body part, and a plurality of unit optical elements arranged on the main body part,
The optical member according to claim 8, wherein the arrangement direction of the plurality of unit optical elements of the optical sheet intersects with the arrangement direction of the plurality of unit optical elements of the second optical sheet.   The ratio which the length by which the said polarizing plate and the said optical sheet are joined in the arbitrary cross sections along the normal line direction of an optical member occupies in the range of 1% or more and 80% or less, 10-9. The optical member as described in any one of these. The optical member according to any one of claims 1 to 10,
A liquid crystal display panel comprising: a liquid crystal cell bonded to the optical member.   A display device comprising the liquid crystal display panel according to claim 11.   The display device according to claim 12, further comprising a light emitter provided at a position facing the optical member of the liquid crystal display panel.   The display device according to claim 12, further comprising a light guide plate provided at a position facing the optical member of the liquid crystal display panel. The optical member according to any one of claims 1 to 10,
A light emitter provided at a position facing the optical member. The optical member according to any one of claims 1 to 10,
An optical module comprising: a light guide plate provided at a position facing the optical member.

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