Spread illuminating apparatus

• US 20020093808A1
• Filed: 01/17/2002
• Published: 07/18/2002
• Est. Priority Date: 01/17/2001
• Status: Active Grant

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Egawa, Motoji
• Granted Patent: US 6,561,662 B2
• Time in Patent Office: Days
• US Class Current: 362/27
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper

Abstract

There is provided a spread illuminating apparatus aiming to minimize the coverage of a liquid crystal screen while securely integrating a light conductive member with a transparent substrate. The light conductive member is wedge-shaped in which the width thereof is in inverse proportion to the increase in distance from a spot-like light source opposing face, and the transparent substrate is trapezoid-shaped in which a side aligned to the spot-like light source opposing face is shorter. A frame and transparent substrate overlapping part becomes larger from one side part to the other side part of the transparent substrate. Since the frame and transparent substrate overlapping part are large enough regardless of the small width of the frame than that of the prior art, the region of a liquid crystal screen can be increased accordingly.

Claims

1. A spread illuminating apparatus, which includes a rectangular transparent substrate made of a light transmissible material, a bar-like light source comprising a bar-like light conductive member made of a transparent material and a spot-like light source disposed on one end face of said light conductive member, and disposed along one end face of said transparent substrate, and which includes a frame held on said transparent substrate so as to cover said light conductive member,

wherein said light conductive member is wedge-shaped such that a width of one end thereof facing said spot-like light source is larger than a width of the other end opposite said one end, and wherein said transparent substrate is structured such that one end thereof facing said light conductive member is inclined and has an inclination angle forming an obtuse angle with respect to one side thereof aligned to said one end of said light conductive member facing said spot-like light source.

2. A spread illuminating apparatus according to claim 1, wherein said inclination angle of said transparent substrate is set to be substantially supplementary to a light conductive member inclination angle which is formed by one side of said light conductive member facing said transparent substrate with respect to said one end thereof facing said spot-like light source.

3. A spread illuminating apparatus according to claim 1 or 2, wherein one light source is provided, and wherein said transparent substrate is trapezoid-shaped such that said one side thereof aligned to said one end of said light conductive member facing said spot-like light source is shorter than the other side opposite to said one side.

4. A spread illuminating apparatus according to claim 1 or 2, wherein two light sources are provided, and wherein each of said two light sources is disposed along each of both ends of said transparent substrate opposite to each other.

5. A spread illuminating apparatus according to claim 4, wherein respective one ends of respective light conductive members of said two light sources, which face respective spot-like light sources, are located to be aligned to one same side of said transparent substrate, and wherein said transparent substrate is trapezoid-shaped.

6. A spread illuminating apparatus according to claim 4, wherein respective one ends of respective light conductive members of said two light sources, which face respective spot-like light sources, are located to be aligned to respective sides of said transparent substrate opposite to each other, and wherein said transparent substrate is parallelogram-shaped.