To prevent an optical defect such as a stripe-like dent from being generated by integratedly providing an engagement member to connect light guide plates to each other on a side of each light guide plate, and providing a rough side surface except an engagement member forming part.
A material of light guide plates 4, 5 is not limited so long as it is of light transmission type, but an acrylic resin and a poly-carbonate plastic are excellent in forming property and preferable. A reflecting surface of the arrangement comprising V-shaped projections is formed on a lower surface of each light guide plate. Recessed and projecting engagement members 46, 56 are formed on side surface parts 43, 53 of the light guide plats except a light-incident surface in advance for fixing the relative position of the lower light guide plate 5 to the upper light guide plate 4. Since the light propagating inside the light guide plates 4, 5 and reflected by a part except the engagement members 46, 56 is superposed with the light reflected from the inside of the engagement members, a diagonal black line-like shadow to be generated with the engagement members 46, 56 as starting points can be eliminated by forming the rough surface shape of the side surfaces 43, 53 of the light guide plates so as to obtain the optimum diffused reflected light.
TEJIMA TERUO
ISHIZAWA ISAO
| JPS61296601A | 1986-12-27 | |||
| JPH09147618A | 1997-06-06 | |||
| JPH09243828A | 1997-09-19 | |||
| JPH10177806A | 1998-06-30 |