Light pipe with quadraspherical depressions for display panels

• US 6,402,334 B1
• Filed: 02/18/1999
• Issued: 06/11/2002
• Est. Priority Date: 02/18/1999
• Status: Expired due to Term

• Current Assignee: Garmin Corporation (Garmin Limited)
• Original Assignee: Garmin Corporation (Garmin Limited)
• Inventors: Yu-San, Lee
• Primary Examiner(s): Sember, Thomas M.
• Application Number:
  US09/252,395
• Time in Patent Office: 1,209 Days
• Field of Search: 362/551, 362/31, 362/307, 362/311, 362/330, 362/329, 362/26, 362/23, 362/339
• US Class Current: 362/619
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• 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
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like

Abstract

A light pipe for use in a backlight for a display panel. The light pipe is formed by a clear plastic panel which receives light at one edge. The panel face is provided with a plurality of quadraspherical depressions which may be arranged in parallel rows. Along each row, the depressions become progressively larger and progressively closer together. The presence of the depressions enhances the efficiency and uniformity of the light distribution from the light pipe panel.

Claims

1. A light pipe for distributing light from a source, said light pipe comprising:

a clear panel having opposite faces and a first side edge and a second side edge, wherein said first side edge is located proximate said light source and is for receiving incoming light, and wherein said second side edge is located distal said light source; and

a plurality of depressions in one of said faces, each depression having a quadraspherical shape, wherein said depressions increase in size as distance from said light source increases, and wherein said depressions are largest proximate said second edge of said panel.

2. A light panel assembly, said light panel assembly comprising:

a clear light pipe panel having opposite faces and a first side edge and a second side edge, one of said faces presenting a plurality of spaced apart depressions each having a quadraspherical shape, wherein said depressions increase in size as distance from said light source increases, and wherein said depressions are largest proximate said second side edge;

a light source for applying light to said edge of the light pipe panel, wherein said first side edge is located proximate said light source and said second side edge is located distal said light source; and

a display panel generally covering said light pipe panel.

3. A backlight for a display assembly, said backlight comprising:

a base panel presenting a reflective surface thereon and having a light source;

a clear light pipe panel on said reflective surface having opposite faces and a first side edge and a second side edge, said first side edge situated to admit light from said light source into the light pipe panel, one of said faces presenting a plurality of spaced apart depressions each having a quadraspherical configuration, wherein said depressions increase in size as distance from said light source increases, and wherein said depressions are largest proximate said second side edge; and

a display panel covering said light pipe panel.