Patent ID: 6631998
Filing Date: 2003-10-14
Classification: G01D,G02B

Abstract:
A spread illuminating apparatus of side light system, comprising:at least one bar-like light source disposed close to and along each of two end surfaces opposing each other of a transparent substrate made of a light-transmissible material; and a light reflection pattern formed on said transparent substrate, and comprising a plurality of grooves shaped substantially inverted-trapezoidal in section such that angles formed by respective inclined surfaces and a datum line extending in both directions from and in parallel with a bottom surface of said groove range from 35Â° to 55Â° and are bilaterally symmetric to each other, and a plurality of flat portions adjacent respectively to the grooves, both the grooves and the flat portions running parallel to the length of said at least one light source; wherein a depth of said grooves constituting said light reflection pattern increases in proportion to the increase in distance from each of said at least one light source, and measures maximum at the center of said transparent substrate.