Asymmetric prism structure, light guide plate, backlight module, and application

• US 8,858,057 B2
• Filed: 07/12/2012
• Issued: 10/14/2014
• Est. Priority Date: 06/28/2012
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Chang, Kuangyao
• Primary Examiner(s): NEILS, PEGGY A
• Application Number:
  US13/583,227
• Publication Number:
  US 20140003085A1
• Time in Patent Office: 824 Days
• Field of Search: 362/617, 362/619, 362/620, 362/339, 359/625
• US Class Current: 362/620
• CPC Class Codes: F21S 41/24 Light guides
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

The asymmetric prism structure contains multiple asymmetric prisms arranged in parallel where each asymmetric prism has a first slant face, a second slant face, and a bottom face, connected end-to-end together. The first slant face directs light beams propagating perpendicular to the prism direction to a lateral side, and the second slant face directs light beams propagating perpendicular to the prism direction to the other lateral side. The present invention further provides a light guide plate, a backlight module, and a related application utilizing the asymmetric prism structure. When vertical asymmetry is present in the timing sequences for the backlight scanning and the signal to the LCD panel, the asymmetric prism structure can reduce the cross-talk near a side from the error signal, thereby enhancing the video quality.

Claims

1. An asymmetric prism structure comprising a plurality of asymmetric prisms arranged in parallel wherein each asymmetric prism has a first slant face, a second slant face, and a bottom face, connected end-to-end together;

the first slant face directs light beams propagating perpendicular to the prism direction to a lateral side;

the second slant face directs light beams propagating perpendicular to the prism direction to the other lateral side;

for a cross-sectional triangle obtained from a plane perpendicular to the prism direction dissecting the asymmetric prism structure, the two slant faces of the asymmetric prism structure correspond to the two slant edges of the cross-sectional triangle, and the bottom face of the asymmetric prism structure corresponds to the bottom edge of the cross-sectional triangle;

the cross-sectional triangle is shaped so that the projections of the two slant edges towards the bottom edge all fall within the bottom edge; and

the lengths of projection p1 and p2 of the two slant edges, respectively, satisfy that p1>

3×

p2 or p2>

3×

p1.

2. The asymmetric prism structure as claimed in claim 1, wherein either p1 or p2 is 0.

3. A light guide plate comprising an asymmetric prism structure as claimed in claim 1 on a top surface of the light guide plate.

4. A light guide plate comprising a symmetric prism structure and the asymmetric prism structure as claimed in claim 1 on a top surface of the light guide plate.

5. A backlight module comprising a light guide plate as claimed in claim 3.

6. A backlight module comprising a light guide plate as claimed in claim 4.