Method and apparatus for enhancing a contrast ratio of a liquid crystal display

• US 20050088590A1
• Filed: 08/17/2004
• Published: 04/28/2005
• Est. Priority Date: 10/22/2003
• Status: Abandoned Application

• Current Assignee: Optima Technology Corporation
• Original Assignee: Optima Technology Corporation
• Inventors: Wu, Long-Hai, Li, Tung-Lung, Hong, Wei-Duz, Lai, Ta-Wang
• Application Number:
  US10/919,374
• Publication Number:
  US 20050088590A1
• Time in Patent Office: Days
• US Class Current: 349/110
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
• CPC Class Codes: G02F 1/133509 Filters, e.g. light shielding masks
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence

Abstract

A liquid crystal display has a liquid crystal display panel, a backlight and a dark layer. The liquid crystal display panel has an upper polarizer, a liquid crystal cell, and a lower polarizer, and the two polarizers both have wide view optical compensation films. The light emitted from the backlight is transmitted to a viewer through the lower polarizer, the liquid crystal cell, and the upper polarizer, sequentially. The dark layer of the invention is placed between the backlight and the viewer, and it lowers the dark-state brightness of the liquid crystal display to improve the downward angle view contrast ratio thereof to be greater than 10.

Claims

1. A method for enhancing contrast ratio, comprising:

providing a dark layer between a viewer and a backlight of a liquid crystal display, wherein the dark layer lowers a dark-state brightness of the liquid crystal display to improve a downward angle view contrast ratio of the liquid crystal display to greater than 10.

2. The method of claim 1, wherein providing the dark layer comprises coating a black dye on an outside of an upper polarizer of the liquid crystal display.

3. The method of claim 1, wherein providing the dark layer comprises coating a black dye between an upper polarizer and a liquid crystal cell of the liquid crystal display.

4. The method of claim 1, wherein providing the dark layer comprises coating a black dye between a lower polarizer and a liquid crystal cell of the liquid crystal display.

5. The method of claim 1, wherein providing the dark layer comprises coating a black dye between a lower polarizer and a backlight of the liquid crystal display.

6. The method of claim 1, wherein providing the dark layer comprises adding a black dye into an adhesive layer of the liquid crystal layer.

7. The method of claim 1, wherein providing the dark layer comprises placing a shading apparatus between the liquid crystal and the viewer.

8. The method of claim 1, wherein a material of the dark layer comprises a AAA.

9. A liquid crystal display, comprising:

a liquid crystal display panel, comprising;

an upper polarizer having a upper wide view optical compensation film;

a liquid crystal cell; and

a lower polarizer having a lower wide view optical compensation film;

a backlight, wherein a light emitted from the backlight is sequentially transmitted to a viewer through the lower polarizer, the liquid crystal cell, and the upper polarizer; and

a dark layer placed between the backlight and the viewer, wherein the dark layer lowers a dark-state brightness of the liquid crystal display to improve a downward angle view contrast ratio of the liquid crystal display to be greater than 10.

10. The liquid crystal display of claim 9, wherein the dark layer is a black dye coating layer.

11. The liquid crystal display of claim 10, wherein a material of the black dye is a AAA.

12. The liquid crystal display of claim 9, wherein the dark layer is an adhesive layer with a black dye.

13. The liquid crystal display of claim 12, wherein a material of the black dye is a AAA.

14. The liquid crystal display of claim 9, wherein the dark layer is placed on an outside of the upper polarizer.

15. The liquid crystal display of claim 9, wherein the dark layer is placed between the upper polarizer and the liquid crystal cell.

16. The liquid crystal display of claim 9, wherein the dark layer is placed between the lower polarizer and the liquid crystal cell.

17. The liquid crystal display of claim 9, wherein the dark layer is placed between the lower polarizer and the backlight.

18. A shading apparatus, placed between a liquid crystal display and a viewer, the shading apparatus comprising:

a dark layer, including a transparent substrate and a black dye, wherein the dark layer lowers a dark-state brightness of the liquid crystal display to improve a downward angle view contrast ratio of the liquid crystal display to be greater than 10; and

a fixing apparatus, configured on the dark layer to fix the dark layer on the liquid crystal display.

19. The apparatus of claim 18, wherein a material of the black dye is a AAA, and a material of the transparent substrate is polycarbonate, acrylic or plastic.

20. A polarizer used in a liquid crystal display, the polarizer comprising:

a supporting film;

a polarizing film on the supporting film;

a wide view optical compensation film on the polarizing film; and

a dark layer in the polarizer, wherein the dark layer lowers a dark-state brightness of the liquid crystal display to improve a downward angle view contrast ratio of the liquid crystal display to be greater than 10.

21. The polarizer of the claim 20, wherein the dark layer is an adhesive layer with a black dye.