Surface emission apparatus

• US 5,775,791 A
• Filed: 04/27/1995
• Issued: 07/07/1998
• Est. Priority Date: 08/31/1992
• Status: Expired due to Term

• Current Assignee: Copal Company Limited (Nidec Corporation)
• Original Assignee: Copal Company Limited (Nidec Corporation)
• Inventors: Nakamura, Shigekazu, Yoshikawa, Yukio
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US08/338,580
• Time in Patent Office: 1,167 Days
• Field of Search: 362/31, 362/26, 362/330, 362/327, 359/49, 349/62, 349/65
• US Class Current: 362/625
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

The present invention relates to a surface emission apparatus for causing light, emitting from a light source arranged to a side of a light-emitting surface thereof, to emerge from the light-emitting surface. The surface emission apparatus includes a transparent light-guide plate in which reflecting shape portions formed with small projecting or concaving portions are arranged on its bottom surface portion opposing the light-emitting surface such that a density of the projecting or concaving portions is gradually increased in accordance with a distance from the light source. Light incident from the light source is reflected by the reflecting shape portions and emerges from the light-emitting surface. Since light emerging from the light source is reflected toward the light-emitting surface in accordance with the density of the reflecting shape portions, uniform light emission can be obtained throughout the entire light-emitting surface. Since the reflecting shape portions are formed in a staggered manner in a direction away from the light source, light emitted from the light source can be easily incident on many projecting or concaving portions directly. The reflecting shape portions are preferably small projecting or concaving portions whose contiguous side portions extending from their vertex portions and contiguous to the bottom surface portion are formed with curved surfaces, or small projecting or concaving portions whose contiguous side portions extending from their vertex portions and contiguous to the bottom surface portion form circular cones.

Claims

1. A surface emission apparatus characterized in that light emitted from a light source arranged near a side portion of a flat light-emitting member thereof emerges from a flat light-emitting surface of said flat light-emitting member, comprising:

a transparent light-guided plate in which reflecting shape portions formed with small projecting portions each with a circular cone having predetermined vertex angle are arranged on a bottom surface portion thereof opposing said flat light-emitting surface such that a density of said projecting portions is gradually increased in accordance with a distance from said light source and also being formed in a staggered manner along parallel lines with respect to said side portion;

said small projecting portions being formed to have small curved surfaces at top end corners of the vertex angles thereof and also being formed to have small curved surfaces at bottom portions thereof so as to continue with said bottom surface portion;

wherein light incident from said light source is reflected by said reflecting shape portions and emerges from said flat light-emitting surface.

2. A surface emission apparatus according to claim 1, wherein said small projecting portions are formed with circular cones whose vertex angles are between a range of 90 to 140 degrees.

3. A surface emission apparatus according claim 1, wherein said transparent light-guide plate including said small projecting portions is made of acrylic resin.

4. A surface emission apparatus characterized in that light emitted from a light source arranged near a side portion of a flat light-emitting member thereof emerges from a flat light-emitting surface of said flat light-emitting member, comprising:

a transparent light-guide plate in which reflecting shape portions formed with small concaving portions are arranged on a bottom surface portion thereof opposing said flat light-emitting surface such that a density of said concaving portions is gradually increased in accordance with a distance from said light source and also being formed in a staggered manner along the parallel lines with respect to said side portion;

said small concaving portions being formed to have small curved surfaces at top end corners thereof and also being formed to have small curved surfaces at bottom portions thereof so as to continue with said bottom surface portion;

wherein light incident from said light source is reflected by said reflecting shape portions and emerges from said flat light-emitting surface.

5. A surface emission apparatus according to claim 4, wherein said small concaving portions are formed with circular cones whose vertex angle is between a range of 90 to 140 degrees.

6. A surface emission apparatus according to claim 4, wherein said transparent light-guide plate together with said small concaving portions is made of acrylic resin.