TW201118429A - Light control plate, surface light source device, and transmissive image display device - Google Patents

Abstract

A light diffusing plate (light control board) (40) allows light incident on a first surface (40a) to be emitted from a second surface (40b). Plural projections (41) extended in a first direction and disposed in parallel in a second direction perpendicular to the first direction are formed on the second surface. In a cross-section orthogonal to the first direction of the projections, an axis passing both ends of the cross-section in the second direction of the projections is denoted as an x axis, and an axis passing centers of both ends on the x axis and being perpendicular to the x axis is denoted as a z axis, a contour shape z(x) of the projections in said cross-section satisfies 0.95×z0(x)≤z(x)≤1.05×z0(x), wherein z0(x) is expressed by Eq.(2). In Eq.(2), wa represents a length in the x-axis direction of projections and ha=0.525wa, ka=-0.4.

Description

201118429 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a light control panel, a surface light source device, and a transmissive image display device. [Prior Art] In a transmissive image display device such as a liquid crystal display device, a direct type surface light source device is used as an example of a light source for outputting backlight of a liquid crystal display unit. As a typical surface light source device, a plurality of light sources are arranged on the back side of a light control panel called a light diffusing plate. In such a surface light source device, it is possible to easily increase the luminance of the light-emitting surface by increasing the number of light sources arranged, and conversely, there is a problem that luminance uniformity is low. In particular, in the vicinity of the light source, the brightness becomes high, so there is a problem of periodic unevenness in light emission, and the front surface periodic light is emitted as the surface light source device is thinned or the number of light sources with low power consumption is reduced. The problem of inhomogeneity has become more serious. In order to ensure the uniformity of the brightness, for example, Japanese Laid-Open Patent Publication No. Hei 6-2 73760 (Patent Document 1) forms a light amount correction pattern corresponding to a distance from a light source on a light diffusing plate which is an example of a light control plate. In the same manner, in the vicinity of the light source side surface of the light diffusing plate, a portion having a zigzag cross section is provided in a portion near the light source side of the light diffusing plate, and the light source having a large amount of scattered light is positive. Light in the vicinity of the upper side [Invention] -5-201118429 However, as in the light amount correction pattern of Patent Document 1, and the cross-sectional jagged shape of Patent Document 2, the backlight structure having a dependency relationship with the position of the light source is known. The positional deviation of the light control plate of the light diffusion plate or the deformation caused by heat, etc., causes the brightness uniformity to deteriorate. Accordingly, an object of the present invention is to provide a light control panel, a surface light source device, and a transmissive image display device using the surface light source device, which are more stable and can suppress unevenness in light emission. A light control panel according to the present invention is characterized in that light incident on the first surface is emitted from a second surface positioned on a second surface opposite to the first surface, and is characterized in that it extends in the first direction and is The plurality of convex portions arranged in parallel in the second direction orthogonal to the first direction are formed on the second surface, and the two portions passing through the cross section in the second direction are formed in the cross section orthogonal to the first direction in the convex portion The axis of the end is the X axis, and when the axis orthogonal to the X axis is the z axis on the X axis, the contour shape of the convex portion in the cross section satisfies the following formula (1) z ( X ) Light control panel, 0. 95Xz〇(x) <z (x) ^1. 05Xz〇(x)· · · (〇 where, in the above formula (1), 2〇(Χ) = Κ-- 1 ; -(2) I-*.+ 16*1—1

V (in the formula (2), wa is the length of the convex portion in the x-axis direction, ha = 0.5 2 5 wa, ka == - 〇 · 4 ) 〇 is configured here, and the convex portion has the aforementioned z (x) Since the cross-sectional shape is shown, the unevenness of light emitted by the light control panel of the present invention can be more stably reduced. A surface light source device according to the present invention includes a light control panel according to the present invention and a plurality of light sources that are disposed apart from each other and that supply light to a second surface of the light control panel. Since the surface light source device ′ is provided with the light control panel according to the present invention, it is possible to more stably reduce the unevenness of light emitted from the light control panel. A transmissive image display device according to the present invention includes: a light control panel according to the present invention; and a plurality of light sources that are disposed apart from each other, and that supply light to the first surface of the light control panel, and from the plurality of light sources A transmissive image display unit that outputs an image by illuminating the light of the light diffusing plate to display an image, and the light-transmitting type image display device of the present invention has a light control panel according to the present invention, so that the unevenness of light emission can be suppressed by stability The light illuminates the transmissive image display unit. Therefore, it is possible to display images excellent in unevenness in light emission in a stable manner. According to the present invention, it is possible to provide a light control panel which can be more stable and suppresses unevenness in light emission, and a surface light source device and a transmission type image display device including the light control panel. [Embodiment] Hereinafter, embodiments of the light control panel, the surface light source device, and the transmissive image display device of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and the description thereof will not be repeated. Moreover, the dimensional ratio of the drawings 'does not necessarily match the ones indicated. 201118429 Fig. 1 is a cross-sectional view showing a configuration of an embodiment of a transmissive image display device according to the present invention. Fig. 1 shows an exploded display transmissive image display device. Fig. 2 is an enlarged view of a light diffusing plate (light control plate) included in the surface light source device included in the transmissive image display device shown in Fig. 1. As the transmissive image display unit 10, for example, a liquid crystal display panel in which the linear polarizing plates 1 2 and 13 are disposed on both surfaces of the liquid crystal cell 11 can be cited. In this case, the transmissive image display device 1 is a liquid crystal display device (or liquid crystal television). The liquid crystal cell 1 1 and the polarizing plates 1 2 and 1 3 can be used by a user of a transmissive image display device such as a liquid crystal display device of the prior art. As the liquid crystal cell, for example, a known liquid crystal cell such as a TFT type or an STN type can be exemplified. The surface light source device 20 is a so-called direct type surface light source device 20, and has a light source unit 30 including a plurality of light sources 31 arranged in parallel. Each of the light sources 31 is a linear light source extending in a direction orthogonal to the direction in which the plurality of light sources 31 are arranged, and is, for example, a straight tubular light source such as a fluorescent lamp (cold cathode line lamp). The plurality of light sources 3 1 are arranged at intervals with the central axes of the respective light sources 31 being located in the same plane P 1 , and when the distance between the central axes of the adjacent two light sources 3 1 , 3 1 is L The distance L is, for example, 10 mm to 150 mm. Here, the light source 31 is linear, and a point light source such as an LED is also possible. Further, the plane P1 shown in Fig. 1 is a plane 〇 plural light source 3 1, which is assumed to be convenient for convenience, as shown in Fig. 1, and is preferably disposed in the light box 32, and the inner surface 32a of the light box 32 is preferably It is formed as a light reflecting surface. Thereby, the light output from each of the light sources 31 is surely outputted to the side of the transmissive image display unit 1 so that the light from each of the light sources 31 can be utilized efficiently. In the embodiment -8 - 201118429, the light source unit 30 will be described with the light box 32 having the above-described preferred configuration. The surface light source device 20 is disposed on the front surface side (upper side in FIG. 1) of the light source unit 30, that is, the light-diffusing sheet as a light control plate disposed on the side of the transmission type image display unit 1 with the light source 31 spaced apart 40. As will be described later, when the distance between the light diffusing plate 40 and the complex light source 31 is D, the distance D is, for example, 3 mm to 50 mm. In order to reduce the thickness of the surface light source device 20, L/D is 2 or more, and preferably l/D is 2.5 or more, and the distance L between the adjacent two light sources 3 1 ' 3 1 and the separation distance are selected. D. The light diffusing plate 40 is configured such that the light from the light source unit 3, that is, the direct light from each of the light sources 31, and the light box are not projected so as to project the image of each of the light sources 3 to the transmissive image display unit 10. The reflected light reflected by the inner surface 3 2 a of the 3 2 is diffused and irradiated toward the transmissive image display unit 1 . The thickness d of the light diffusing plate 4 is not more than 2 m m. The light diffusing plate 40 is made of a transparent material. The refractive index of the transparent material is usually from 1.56 to 1.62 Å. As the transparent material, a transparent resin material or a transparent glass material can be exemplified. Further, as the transparent resin material, a polycarbonate resin (refractive index: U9), an MS resin (methyl methacrylate - this ethylene-based copolymer resin) (refractive index: 1.56 to 1.59), and a polystyrene tree are exemplified. Sb (refractive index · 1 · 5 9 ) or the like 'is a polystyrene resin from the viewpoint of cost and low moisture absorption rate. When a transparent resin material is used as the transparent material, an additive such as an ultraviolet absorber, a charge preventive agent, an oxidation preventive agent, a process stabilizer, a flame retardant, or a slip agent may be added to the transparent resin material. These additives may be used singly or in combination of two or more. Examples of the ultraviolet absorber include a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a cyan ac ac ac urate (cya η 〇acry 1 ate) ultraviolet absorber. And a malonate-based ultraviolet absorber, a grassy diphenylamine-based ultraviolet absorber, a triazine-based ultraviolet absorber, or the like, preferably a benzotriazole-based ultraviolet absorber or a triazine-based ultraviolet absorber. . The transparent resin material usually does not contain a light diffusing agent as an additive, but in the present invention, a light diffusing agent may be added as long as it is not significantly detrimental to the effect. As shown in Fig. 1 and Fig. 2, the light diffusing plate 40 has a substantially flat first surface 40a on the light source unit 30 side and a second surface 40b on the transmission type image display unit 10 side. On the second surface 4〇b, a plurality of convex portions 41 are formed. In the light diffusing plate 40 in which the convex portion 41 is formed, the thickness ch is the distance between the top portion of the convex portion 41 and the first surface 40a. As shown in Fig. 2, each of the convex portions 41 is a linear optical element extending in one direction. The plurality of convex portions 41 are arranged side by side in a direction approximately orthogonal to the direction in which they extend. The plurality of convex portions 41 are formed so as to be dense from the one side (40c) to the other side (40d) of the light diffusing plate 40 (see Fig. 1). The cross-sectional shape orthogonal to the extending direction of each convex portion 41 is approximately the same between the plurality of convex portions 41. Further, the distance D and the distance L are selected such that the distance L between the distance D and the distance L between the adjacent two light sources 31 and 31 is 2 or more, and preferably 2.5 or more. The foregoing -10 - 201118429 Fig. 3 is a view showing an example of a sectional shape orthogonal to the extending direction of the convex portion, and an enlarged convex portion is shown. The cross-sectional shape of the convex portion 41 will be described using a partial xz coordinate system set as shown in Fig. 3 . The X-axis constituting the χζ coordinate system is parallel to the axis of the arrangement direction (second direction) of the plurality of convex portions 41, and the z-axis is an axis parallel to the thickness direction (direction orthogonal to the first and second directions). . The X z plane of the X z coordinate system, the ends 4 1 a, 4 1 a are located on the X axis, the top 4 1 b is located on the z axis, and the cross section shape of the convex portion 4 1 is symmetric to the z axis. contour line. This outline is expressed by satisfying z ( X ) of the following formula (3). 〇· 95Χζ„ (χ) ύζ (x) ^1. 05Xz【,(x)...(3) where 'in the above formula (3), team---z〇{x) = ha---- — (4) 1 - (土) In the formula (4), 'you 3 is the length of the convex portion 41 in the x-axis direction, ha = 0 · 5 2 5 wa, ka = - 〇. 4. The maximum height in the x-axis direction between the ends 4丨a and 4 1 a of the convex portion 4丨 when the shape of the convex portion 4丨 is expressed by Zq ( χ ). In Fig. 3, the satisfaction formula (3) is illustrated. In the range of Ζΰ ( Χ ), only a certain multiple (for example, 1 time) shape is stretched in the 2 direction. As shown in Fig. 4, z is determined for a certain width Wa. (x) is as long as it is the outline of the area between the outline represented by 〇·95ζ() ( x ) and the outline indicated by 1 .〇5Zq ( x ). -11 - 201118429 The width Wa of the shape portion 4 1 is 40 μm or more, preferably 250 μm or more, and is transmitted or transmitted through the image display device 1. Since the convex shape is confirmed by the naked eye, it is usually 800 μm. Τ The following is a wide wa, specifically 400μηι and wa = 325μηι, but... The layer which is not transparent or may be a transparent material which is different from each other may be a multi-layered board. The light-diffusing board 40 is a multi-layered board, or both sides, usually It is formed into a thick skin layer of ΙΟμηι~200μηι ΙΟΟμιη, and it is preferable to use a UV absorber as a constituent of the skin layer. By preventing the deterioration of the violet 40 contained by the light source or the light from the outside, especially as a light source The light pipe is deteriorated by ultraviolet rays from the fluorescent tube, and the skin layer is preferably formed. In this case, it is preferable that the second surface is not shaped. As the ultraviolet absorber constituting the skin layer, In this case, the content is usually 5% by mass to 5% by mass, preferably 9% by mass. The light diffusing plate 40 can be produced, for example, from a transparent material. Further, a transparent tree can be used as a transparent material, for example, by injection molding. It is easy to form by extrusion molding method. It is usually not easy to form a part of the surface light source device 20, and it is preferably 450 μm η wa = 4 1 0 μχη, wa — specific. The light-diffusing sheet 40 having a single-layered laminated structure has a structure in which the transparent resin material of 20 μm is preferably the most relevant structure, and the light diffusing plate or the like can be caused by the outer layer, and the first surface can be prevented. 40a is formed into a skin layer by a transparent resin material, and the transparent resin material is used as a method of cutting a resin material by a method of cutting out a resin material of 1% by mass to 25%. For example, a press forming method, etc. -12-201118429 Light diffusing plate 40, it is also possible to apply an antistatic agent on one side or both sides. By applying an antistatic agent, it is possible to prevent dust from adhering due to static electricity, and to prevent a decrease in light transmittance due to adhesion of dust. In the surface light source device 20 and the transmissive image display device 1 including the light diffusing plate 40, the light output from each of the light sources 31 of the light source unit 30 is directly reflected on the inner surface 32a of the light box 32 and is incident on the light diffusing plate. 40. The light incident on the light-diffusing plate 40 is irradiated toward the transmissive image display unit 10 by the second surface 40b. At this time, since the plurality of convex portions 4 1 are formed on the second surface 40b of the light diffusing plate 40, the light is emitted through the convex portion 4 1 . Since the convex portion 4 1 has a cross-sectional shape represented by z ( X ) described above, light is refracted to various directions in response to the light passing position (ejection position). By such a diffusion action, light from the light source 31 is diffused to generate planar light, and the image of the light source 31 is not projected onto the transmissive image display unit 10. In the surface light source device 20 including the light diffusing plate 40, it is possible to output light in which unevenness in light emission is suppressed. Further, in the surface light source device 20, the change in luminance uniformity is also suppressed for the change in L/D. Then, in the transmissive image display device 1 including the light diffusing plate 40, light having suppressed light emission unevenness can illuminate the transmissive image display unit 10, so that display quality can be improved. Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the light control plate is described by the light diffusing plate 40, but the invention is not limited thereto, as long as the light output by the complex light source is adjusted parallel to the brightness uniformity in the plane of the plane in which the complex light source is disposed. The parts are all right. For example, the light control plate may be a light-adjusting plate of an optical sheet or an optical film such as a cymbal or a lens sheet, which has a plurality of the convex portions on the light-emitting side of the light plate of the transparent material material-13-201118429. . Further, the end 41a of the cross-sectional shape of the adjacent convex portion 41 is overlapped in the direction in which the convex portions 41 are arranged. However, in the cross-sectional shape of the light diffusing plate 40, a flat portion (for example, due to manufacturing errors) may occur. ). Further, as described so far, the plurality of light sources 31 having the light source unit 30 are arranged at substantially equal intervals with an interval L therebetween, but the distance between the adjacent two light sources 31 and 31 may be different. In this case, the distance between the light sources 3 1 and the ratio of the distance between the light source 31 and the light control plate can be defined using the average distance Lm between the adjacent two light sources 3 1, 3 1 . In the above description, the light diffusing plate 40 is exemplified. However, the surface light source device 20 may be used in two or more, and preferably three or four light diffusing plates 40 are overlapped. The two or more light diffusing plates 40 are superposed so that the first surface 40a becomes the light source 30 side. Further, at least two of the light diffusing plates 40 are preferably orthogonal to each other in the extending direction (first direction) of the convex portion 41 of the light diffusing plate 40. [Industrial Applicability] According to the present invention, it is possible to provide a light control panel which can be more stable and suppresses unevenness in light emission, and a surface light source device and a transmissive image display device including the light control panel. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a configuration of an embodiment of a transmissive image display device of the present invention -14-201118429. Fig. 2 is a cross-sectional view showing an optical expansion plate (light control plate) used in the transmissive image display device shown in Fig. 1. Fig. 3 is a view showing a sectional shape of a convex portion of a light diffusing plate (light diffusing plate). Fig. 4 is a view showing conditions under which the outline of the sectional shape of the convex portion is satisfied. [Description of main component symbols] 1 : Transmissive image display device 10 : Transmissive image display unit 2 0 : Surface light source device 3 0 : Light source unit 3 1 : Light source 4 〇: Light diffusing plate (light control plate) 40a : 1 face 40b: 2nd face 4 1 c, 4丨d : - Pair of sides 4 1 : Convex part 4 1 a : End of the convex part 4 1 b : Top of the convex part

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Claims (1)

201118429 VII. Patent application scope: 1. A light control panel is characterized in that light incident on the first surface can be emitted from a second surface located on the opposite side of the first surface, and is characterized in that: the first direction is extended. At the same time, a plurality of convex portions arranged side by side in the second direction orthogonal to the first direction are formed on the second surface, and the cross section orthogonal to the first direction of the convex portion passes through the When the two end axes of the two directions in the two directions are the X axis, and the axis passing through the both ends of the X axis and the axis orthogonal to the X axis is the z axis, the contour shape of the front convex portion is formed in the cross section. To satisfy the following formula (1), the light control panel represented by z ('X), 0. 95Χζ〇(χ) ύζ (x) ^1. 05Χζ〇(χ)· · · (〇 where, in the above formula (1) ), 1 乂 + In the formula (2), wa is the length of the convex portion in the z-axis direction, and ha 0.5 2 5 w a ' ka = -0.4. A surface light source device comprising: the light control panel described in claim 1; and a plurality of light sources arranged to be spaced apart from each other to supply light to the first surface of the front light control panel. 3. A transmissive image display device, comprising: a light control panel according to claim 1; and a plurality of light beams that are disposed apart from each other and supplied to the first surface of the light control panel a light source: a transmissive image display portion that is placed in a set surface by light from the plurality of light sources and is placed on the surface of the light control panel. . -17-