| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lightweight light diffusing plate (1) having a plurality of hollow portions (5) formed therein. <P>SOLUTION: The light diffusing plate (1) has a plurality of hollow portions (5) formed therein and the hollow portions extend in parallel with one another in the light diffusing plate. For example, the sectional shape of the hollow portion (5) is a triangular shape and a circular shape. A ratio of the total sum (S<SB>5</SB>) of sectional areas of the hollow portions (5) to total sectional area of the light diffusing plate (1) including the hollow portion areas is in a range of from 5% to 75%. The light diffusing plate (1) has a structure such that a plurality of rib members (4) which connect the both flat plates (2) with each other and extend in parallel with one another are arranged between a pair of flat plates (2) arranged in parallel to each other with a spacing (t<SB>s</SB>) therebetween, the plurality of rib members (4) are placed at an angle (θ) of 30° to 75° with respect to the flat plate (2) and the adjacent rib members (4) are in contact with one another at the vicinity of the line (4a) at which the rib members (4) are in contact with the flat plate (2), whereby a triangular hollow portion (5) in its section is formed by the flat plate (2) and the rib members (4). For example, a direct-type backlight (8) of a flat panel display device (6) is composed of the light diffusing plate (1). <P>COPYRIGHT: (C)2006,JPO&NCIPI |
