Backlight module and brightness enhancement film thereof

• US 20060209415A1
• Filed: 07/08/2005
• Published: 09/21/2006
• Est. Priority Date: 03/16/2005
• Status: Active Grant

• Current Assignee: Optronic Sciences LLC (Lumina Innovations LLC)
• Original Assignee: AU Optronics Corporation
• Inventors: Chen, Chih-Kuang, Kao, Ko-Chia, Huang, Jyh-Haur
• Granted Patent: US 7,262,916 B2
• Time in Patent Office: Days
• US Class Current: 359/599
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

A backlight module includes a light source, a light guide disposed on one side of the light source, a reflector disposed under the light guide, a lower diffuser disposed on the light guide, and a brightness enhancement film, which is disposed on the lower diffuser and includes a main part and several prism structures disposed side by side on a main part plane of the main part. Each prism structure includes first to third triangular prisms. The second triangular prism is adjacent to one side of the first triangular prism, and an adjacent angle adjacent to a base angle of the first triangular prism is a right angle. The third triangular prism is adjacent to another side of the first triangular prism, and an adjacent angle adjacent to another base angle of the first triangular prism is a right angle.

Claims

1. A brightness enhancement film, comprising:

a main part having a main part plane; and

a plurality of prism structures disposed side by side on the main part plane, each of the prism structures comprising;

a first triangular prism;

a second triangular prism adjacent to one side of the first triangular prism, an adjacent angle adjacent to a base angle of the first triangular prism being a first right angle; and

a third triangular prism adjacent to another side of the first triangular prism, an adjacent angle adjacent to another base angle of the first triangular prism being a second right angle.

2. The brightness enhancement film according to claim 1, wherein the second triangular prism and the third triangular prism are symmetrical with respect to the first triangular prism, and a top angle of the second triangular prism is equal to a top angle of the third triangular prism.

3. The brightness enhancement film according to claim 1, wherein a top angle of the second triangular prism is 45°

.

4. The brightness enhancement film according to claim 1, wherein a top angle of the third triangular prism is 45°

.

5. The brightness enhancement film according to claim 1, wherein a top angle of the first triangular prism is a third right angle.

6. The brightness enhancement film according to claim 5, wherein the base angle of the first triangular prism is 45°

.

7. A brightness enhancement film, comprising:

a main part having a main part plane; and

a plurality of prism structures disposed side by side on the main part plane, each of the prism structures comprising;

a first triangular prism having a first plane, a second plane and a third plane, wherein the third plane overlaps with the main part plane, the third plane has a long side substantially parallel to and equal to one side of the main part plane, and the first plane and the second plane define a first angle;

a second triangular prism having a fourth plane, a fifth plane and a sixth plane, wherein the sixth plane overlaps with the main part plane, the sixth plane has a long side overlapping with the long side of the third plane, the fourth plane is perpendicular to the main part plane, and the fourth plane and the fifth plane define a second angle; and

a third triangular prism having a seventh plane, a eighth plane and a ninth plane, wherein the ninth plane overlaps with the main part plane, the ninth plane has a long side overlapping with another long side of the third plane, the seventh plane is perpendicular to the main part plane and faces the fourth plane, and the seventh plane and the eighth plane define a third angle.

8. The brightness enhancement film according to claim 7, wherein the second triangular prism and the third triangular prism are symmetrical with respect to the first triangular prism, and the second angle equals the third angle.

9. The brightness enhancement film according to claim 8, wherein each of the second angle and the third angle is 45°

.

10. The brightness enhancement film according to claim 7, wherein the first angle is 90°

.

11. The brightness enhancement film according to claim 10, wherein the first triangular prism is an isosceles right triangular pillar.

12. A backlight module, comprising:

a light source;

a light guide disposed on one side of the light source;

a reflector disposed under the light guide;

a lower diffuser disposed on the light guide; and

a brightness enhancement film disposed on the lower diffuser, comprising;

a main part including a main part plane; and

a plurality of prism structures disposed side by side on the main part plane, each of the prism structures comprising;

a first triangular prism having a first plane, a second plane and a third plane, wherein the third plane overlaps with the main part plane, the third plane has a long side substantially parallel to and equal to one side of the main part plane, and the first plane and the second plane define a first angle;

a second triangular prism having a fourth plane, a fifth plane and a sixth plane, wherein the sixth plane overlaps with the main part plane, the sixth plane has a long side overlapping with the long side of the third plane, the fourth plane is perpendicular to the main part plane, and the fourth plane and the fifth plane define a second angle; and

a third triangular prism having a seventh plane, a eighth plane and a ninth plane, wherein the ninth plane overlaps with the main part plane, the ninth plane has a long side overlapping with another long side of the third plane, the seventh plane is perpendicular to the main part plane and faces the fourth plane, and the seventh plane and the eighth plane define a third angle.

13. The backlight module according to claim 12, wherein the second triangular prism and the third triangular prism are symmetrical with respect to the first triangular prism, and the second angle equals the third angle.

14. The backlight module according to claim 13, wherein each of the second angle and the third angle is 45°

.

15. The backlight module according to claim 12, wherein the first angle is 90°

.

16. The backlight module according to claim 15, wherein the first triangular prism is an isosceles right triangular pillar.

17. The backlight module according to claim 12, further comprising an upper diffuser disposed on the brightness enhancement film.

18. The backlight module according to claim 12, further comprising a light source reflector disposed on another side of the light source.