Kuraray Co., Ltd.

Seiji Kinoshita

Yoshiki Mukoo

Yukihiro Yanagawa

Iichiro Fukuda

Provided is an edge-light type illumination device capable of increasing luminance directly thereunder and capable of providing anisotropy to the luminance distribution. Light to be emitted from an emission surface () of a light-guide plate () fulfills a condition (1) E/E&#x3e;2.0 and a condition (2) E(20&#xb0;,0&#xb0;)/E(20&#xb0;,90&#xb0;)&#x3e;1.2. Here, average intensity of light to be emitted from the emission surface () is Em and total light intensity of the light to be emitted in a Z-axis direction is Etotal, the total light intensity Etotal(20&#xb0;, 0&#xb0;) of the light to be emitted is &#x3a3;&#x394;Pi(20&#xb0;,0&#xb0;)/&#x394;&#x3c9; when an angle &#x3b8; of the light to be emitted relative to a Z-axis direction is 20&#xb0; and an angle &#x3c6; of the light to be emitted relative to an X-axis direction is 0&#xb0;, and the total light intensity Etotal(20&#xb0;, 90&#xb0;) of the light to be emitted from the emission surface () is &#x3a3;&#x394;Pi(20&#xb0;,90&#xb0;)/&#x394;&#x3c9; when the angle &#x3b8; of the light to be emitted relative to the Z-axis direction is 20&#xb0; and the angle &#x3c6; of the light to be emitted relative to the X-axis direction is 90&#xb0;.

Illumination device having a light guide having convex and concave patterns

A light guide plate has at a bottom surface thereof a recessed strip. The recessed strip has first oblique surfaces and second oblique surfaces, a vertical angle &#x3b8;formed by the first oblique surfaces facing each other is set in a range of 95&#xb0; to 110&#xb0; while an apparent vertical angle &#x3b8;formed by the second oblique surfaces facing each other is set in a range of 60&#xb0; to 75&#xb0;. When defining one side of each of the first oblique surfaces as a first oblique side and one side of each of the second oblique surfaces as a second oblique side and the total length of the first oblique side and second oblique side as a total oblique side length, the ratio of the oblique side length of the second oblique side to the total oblique side length is set in a range of 40% to 65%.

Lighting device

An object of the present invention is to provide a surface light source element configured to enhance projection light from an opening boundary of a supporting frame (), wherein the projection light is required as a surface light source element, so that the surface light source element makes it possible to clearly illuminate an observation direction even in the case where the surface light source element is made large in size or thin in thickness. In the surface light source element using a light-guiding plate () provided with a prism pattern of a groove () that is V-character-like in section on a side of the bottom surface (), the light-guiding plate () is characterized in comprising the prism pattern that enters from the edge of an opening of a supporting frame () to the incident edge surface side, wherein the prism pattern is arranged in a central direction of the light guide plate from a position of an angle &#x3b8; ranging from 20&#xb0; to 60&#xb0; expressed by the following equation: L=T&#xd7;tan &#x3b8; where T: a thickness (mm) of the light guide plate (), and L: a distance (mm) entering from the edge of the opening at the supporting frame () on an inner side of a liquid crystal panel to a back surface of the supporting frame ().

Surface light source element and image display apparatus including the same

A light guide plate capable of omitting use of a directional sheet such as a prism sheet as much as possible and ensuring a viewing angle without decreasing brightness in the vertical direction. A light guide plateis used for an edge-light surface illuminant device. The light guide plate comprises an emission plane, a bottom planefacing the emission planeand an incident end facewhich enters light emitted from a primary light sourceprovided in a side face between the emission planeand the bottom plane. Each of the emission planeand the bottom planecomprises a pattern having convex portions and/or concave portions formed at predetermined pitches. The pattern formed on the emission planeis orthogonal to the incident end faceand also the pattern formed on the bottom planeis parallel to the incident end face. The emission planeor the bottom planecomprises a trapezoidal convex portionand a trapezoidal concave portionwhich are alternately arranged. If a diffusion treatment is performed on the surface of each of the convex portions, the light guide plate which has reduced glare on the surface and has a superior surface quality can be obtained.

Light guide plate, production method therefor, and surface light source device provided with it

This invention provides a methyl methacrylate resin light guide for use in a surface light source device. The methyl methacrylate resin light guide can reduce the occurrence of dark lines and can improve the screen image quality of a surface light source device. The light guide characterized by including a methyl methacrylate resin and fine particles. Herein, not less than 0.01 parts by mass and not more than 0.5 parts by mass of the fine particles are dispersed in 100 parts by mass of the methyl methacrylate resin. In addition, the absolute value of a difference in refractive index between the fine resin particles and the methyl methacrylate resin is not less than 0.001 and not more than 0.02, the fine resin particles have an average particle size of not less than 1 &#x3bc;m and not more than 10 &#x3bc;m.

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Tsukuba, Japan

Seiji Kinoshita