Spread illuminating apparatus with light reflection-diffusion layer on optical path conversion means
AssigneeMinebea Co., Ltd.
InventorsTakahiro Shimura, Yoshiki Nakamura, Koichi Toyoda
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Abstract
The present invention provides a spread illuminating apparatus which can ensure uniform brightness over its entire screen. A light reflection-diffusion layer is formed on a light conductive member at a face provided with an optical path conversion means. Light emitted from spot-like light sources is reflected efficiently by the light reflection-diffusion layer toward a transparent substrate, and light intensity degrades in a substantially linear manner with the increase in distance from respective spot-like light sources. Sharp change of brightness on an observation surface can be prevented due to the light intensity degrading linearly.
Claims15
A spread illuminating apparatus comprising:
- a transparent substrate which is made of a light-transmissible material;
- and
- a light source which is composed of a bar-like light conductive member having, on at least one longitudinal side face thereof, an optical path conversion means comprising a large number of light scattering portions, and spot-like light sources provided on ends thereof, said light sources being disposed along and close to an end face of said transparent substrate;
- wherein a light reflection-diffusion layer is formed on said at least one longitudinal side face of said bar-like light conductive member so as to cover said optical conversion means.
Dependencies are inferred from the claim text.