Transflective type liquid crystal display device

• US 7,365,814 B2
• Filed: 10/26/2004
• Issued: 04/29/2008
• Est. Priority Date: 12/30/2003
• Status: Expired due to Fees

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kang, Hoon
• Primary Examiner(s): NGO, HUYEN LE
• Application Number:
  US10/973,358
• Publication Number:
  US 20050140872A1
• Time in Patent Office: 1,281 Days
• Field of Search: 349/114, 349/158, 349/96, 349/200, 349/138, 349/62, 349/65, 359618-620, 359641-642
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133555 Transflectors

Abstract

A liquid crystal display device includes a first substrate, a second substrate facing the first substrate, a liquid crystal layer made of liquid crystals injected between the first and the second substrates, and a backlight assembly arranged on an outer surface of the first substrate. The first substrate has a light guiding pattern containing a periodic structure formed from a medium whose refractive index is different from the refractive index of the first substrate. The light guiding pattern is operative to internally reflect light from the backlight assembly to a transmission region.

Claims

1. A transflective type liquid crystal display device comprising:

a first substrate;

a light guiding pattern containing a medium whose refractive index is different from a refractive index of the first substrate, the light guiding pattern being disposed on an outer side of the first substrate;

a second substrate facing the first substrate;

a liquid crystal layer containing liquid crystals injected between the first and the second substrates; and

a backlight assembly arranged on an outer surface of the first substrate, each element of the light guiding pattern being operative to guide light to a transmission region by reflecting light provided from the backlight assembly inside the light guiding pattern using total internal reflection.

2. The transflective type liquid crystal display device according to claim 1, further comprising a reflector disposed on an inside side of the first substrate as another light guiding pattern, the reflector defining a reflection region and the transmission region such that the reflector is present in the reflection region and the reflector is not present in the transmission region.

3. The transflective type liquid crystal display device according to claim 2, wherein a cell gap in the transmission region is twice a cell gap in the reflection region.

4. The transflective type liquid crystal display device according to claim 2, wherein the reflection region has a greater width than the transmission region.

5. The transflective type liquid crystal display device according to claim 2, further comprising a passivation layer on which the reflector is disposed.

6. The transflective type liquid crystal display device according to claim 5, wherein the passivation layer is disposed only in the reflection region.

7. The transflective type liquid crystal display device according to claim 5, further comprising a transparent electrode on which the passivation layer is disposed.

8. The transflective type liquid crystal display device according to claim 2, wherein each element of the light guiding pattern corresponds with the transmission region, and a width of each element of the light guiding pattern is greater than a width of the corresponding portion of the transmission region.

9. The transflective type liquid crystal display device according to claim 1, further comprising first and second polarizing plates, whose optical transmission axes are perpendicular each other, arranged on outer surfaces of the first and the second substrates, respectively.

10. The transflective type liquid crystal display device according to claim 1, further comprising a collimator arranged between the first substrate and the backlight assembly, the collimator for modulating light provided from the backlight assembly into parallel light.

11. The transflective type liquid crystal display device according to claim 1, wherein each element of the light guiding pattern is formed in a position that corresponds to a transmission region.

12. The transflective type liquid crystal display device according to claim 11, wherein a majority of the light guiding pattern is formed in a position that corresponds to the transmission region.

13. The transflective type liquid crystal display device according to claim 1, wherein a refractive index of the light guiding pattern is greater than a refractive index of the first substrate.

14. The transflective type liquid crystal display device according to claim 1, wherein the light guiding pattern is tapered such that a width of the light guiding pattern decreases with decreasing distance to the liquid crystal layer.

15. The transflective type liquid crystal display device according to claim 1, wherein the light guiding pattern is a V-shaped pattern.

16. The transflective type liquid crystal display device according to claim 1, wherein the light guiding pattern is a rectangular shaped pattern.

17. The transflective type liquid crystal display device according to claim 1, wherein the light guiding pattern is a periodic structure.

18. The transflective type liquid crystal display device according to claim 1, wherein the light guiding pattern extends from the outer surface of the first substrate towards the liquid crystal layer.

19. The transflective type liquid crystal display device according to claim 18, wherein the light guiding pattern terminates before reaching an inner surface of the first substrate opposing the outer surface of the first substrate.

20. The transflective type liquid crystal display device according to claim 18, wherein the light guiding pattern at the outer surface of the first substrate covers substantially all of the outer surface of the first substrate.

21. A display device comprising:

a light provider; and

a substrate having a periodic light guiding pattern formed therein, the light guiding pattern and substrate having different refractive indices that are different enough such that light from the light provider entering the light guiding pattern is reflected by total internal reflection inside the light guiding pattern and progressed towards a front surface of the display device.

22. The display device according to claim 21, further comprising a reflector disposed on a reflecting region of an inside side of the substrate as another light guiding pattern, a transmission region of the opposing side of the substrate devoid of the reflector.

23. The display device according to claim 22, wherein a cell gap in the transmission region is twice a cell gap in the reflection region.

24. The display device according to claim 22, wherein the reflection region has a greater width than the transmission region.

25. The display device according to claim 22, further comprising a passivation layer on which the reflector is disposed, the passivation layer disposed only in the reflection region.

26. The display device according to claim 25, further comprising a transparent electrode disposed on the substrate and on which the passivation layer is disposed.

27. The display device according to claim 22, wherein each element of the light guiding pattern corresponds with the transmission region, and a width of each element of the light guiding pattern is greater than a width of the corresponding portion of the transmission region.

28. The display device according to claim 21, wherein the light guiding pattern extends from a surface of the substrate facing the light provider and terminates before reaching an opposing surface.