The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 22, 2000
Filed:
Jul. 31, 1997
Tsuyoshi Ishikawa, Tokyo, JP;
Hiroshi Yamazaki, Higashimatsuyama, JP;
Enplas Corporation, Kawaguchi, JP;
Yasuhiro Koike, Yokohama, JP;
Abstract
In a surface light source device of side light type applied to a liquid crystal display or the like, a light control member is prevented from clinging to a light guide plate. The light guide plate is formed by means of injection molding with molds 16A and 16B. The molds 16A and 16B have an additional cavity 13 in a portion corresponding to a position close to an incidence surface of the light guide plate 11, with a gate G being arranged in the cavity. In the mold 16B, its inside surface corresponding to an emitting surface 12 is roughened. According to gradient in roughness, the emitting surface of a light guide plate to be manufactured is roughened so as to have uniform or graded roughness. On a center line C--C, the inside surface is much roughened in a portion distant from the cavity 13. Further, on a crossing line D--D, the inside surface is roughened so as to reduce the roughness according to distance from the center. If the gradient in roughness on the inside surface of the mold 16B is intensified, the emitting surface of the light guide plate may be roughened so as to have graded roughness. It is thereby possible to prevent clinging of the control member from occurring even when deformation of the light guide plate occurs. (FIG. 5b)