Reflective cholesteric liquid crystal display device and manufacturing method for the same

• US 20020113765A1
• Filed: 02/19/2002
• Published: 08/22/2002
• Est. Priority Date: 02/19/2001
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Yoon, Sung-Hoe, Moon, Jong-Weon
• Granted Patent: US 6,833,889 B2
• Time in Patent Office: Days
• US Class Current: 345/88
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n

Abstract

A reflective cholesteric liquid crystal (CLC) display device has a reflection layer in or on a cholesteric liquid crystal color filter to increase a luminance and a contrast ratio of a liquid crystal display device. A reflective cholesteric liquid crystal display device includes a first substrate, an absorption layer on the first substrate, a cholesteric liquid crystal color filter on the absorption layer, a reflection layer on the absorption layer, the reflection layer reflecting light in a whole range of wavelengths, a first electrode on the cholesteric liquid crystal (CLC) color filter, a second substrate spaced apart from and over the first substrate, a second electrode beneath the second substrate, a retardation layer on the second substrate, a polarizer on the retardation layer and a liquid crystal layer between the first electrode and the second electrode.

Claims

1. A reflective cholesteric liquid crystal (CLC) display device, comprising:

a first substrate;

an absorption layer on the first substrate;

a cholesteric liquid crystal (CLC) color filter on the absorption layer;

a reflection layer on the absorption layer, the reflection layer reflecting light in a range of wavelengths;

a first electrode on the cholesteric liquid crystal (CLC) color filter;

a second substrate spaced apart from and over the first substrate;

a second electrode beneath the second substrate;

a retardation layer on the second substrate;

a polarizer on the retardation layer; and

a liquid crystal layer between the first electrode and the second electrode.

2. The device according to claim 1, wherein the reflection layer may contact the cholesteric liquid crystal (CLC) color filter laterally.

3. The device according to claim 2, wherein the reflection layer may be formed of cholesteric liquid crystal (CLC) polarizer.

4. The device according to claim 1, wherein the reflection layer is interposed between portions of the cholesteric liquid crystal (CLC) color filter.

5. The device according to claim 1, wherein the reflection layer may be formed on a whole area of the first substrate in which the cholesteric liquid crystal (CLC) color filter is formed.

6. The device according to claim 5, wherein the reflection layer may be formed of cholesteric liquid crystal (CLC) polarizer.

7. The device according to claim 5, wherein the cholesteric liquid crystal (CLC) color filter has at least two layers that display a same color corresponding to each pixel region, the at least two layers each reflecting light in a different range of wavelengths.

8. The device according to claim 5, wherein the reflection layer is partially transimissive.

9. The device according to claim 1, wherein the range of wavelengths is the spectrum of visible light.

10. The device according to claim 1, wherein the range of wavelengths is a subset of the spectrum of visible light.

11. The device according to claim 1, wherein the range of wavelengths includes at least two colors.

12. The device according to claim 1, wherein the range of wavelengths is a range of wavelengths of ambient light.

14. The method according to claim 13, wherein the reflection layer may contact the cholesteric liquid crystal (CLC) color filter laterally.

15. The method according to claim 14, wherein the reflection layer may be formed of cholesteric liquid crystal (CLC) polarizer.

16. The method according to claim 13, wherein the reflection layer is interposed between portions of the cholesteric liquid crystal (CLC) color filter.

17. The method according to claim 13, wherein the reflection layer may be formed on a whole area of the first substrate in which the cholesteric liquid crystal (CLC) color filter is formed.

18. The method according to claim 17, wherein the reflection layer is partially transimissive.

19. The method according to claim 17, wherein the reflection layer may be formed of cholesteric liquid crystal (CLC) polarizer.

20. The method according to claim 13, wherein the cholesteric liquid crystal (CLC) color filter has at least two layers that display a same color corresponding to each pixel region, the at least two layers each reflecting light in a different range of wavelength.

21. The method according to claim 13, wherein the range of wavelengths is the spectrum of visible light.

22. The method according to claim 13, wherein the range of wavelengths is a subset of the spectrum of visible light.

23. The method according to claim 13, wherein the range of wavelengths includes at least two colors.

24. The method according to claim 13, wherein the range of wavelengths is a range of wavelengths of ambient light.

13. A method of manufacturing a reflective cholesteric liquid crystal (CLC) display device, comprising:

preparing a first substrate;

forming an absorption layer on the first substrate;

forming a cholesteric liquid crystal (CLC) color filter on the absorption layer;

forming a reflection layer on the absorption layer, the reflection layer capable of reflecting light in a range of wavelengths;

forming a first electrode on the cholesteric liquid crystal (CLC) color filter and on the reflection layer;

preparing a second substrate;

forming a second electrode on the second substrate;

disposing the first substrate and the second substrate so that the first electrode and the second electrode face each other;

injecting liquid crystal between the first electrode and the second electrode; and

forming a retardation layer on the second substrate and a polarizer on the retardation layer.