Liquid crystal display device in which generation of moire fringes is prevented

• US 20010017678A1
• Filed: 02/26/2001
• Published: 08/30/2001
• Est. Priority Date: 02/29/2000
• Status: Active Grant

• Current Assignee: Onanovich Group AG LLC (Intellectual Ventures LLC)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Kobayashi, Masakazu
• Granted Patent: US 6,825,899 B2
• Time in Patent Office: Days
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133616 Front illuminating devices

Abstract

A liquid crystal display device is disclosed that provides improved color image quality of the display screen by preventing the generation of moiré fringes, thereby realizing an improvement in color clarity, a reduction in color inconsistency, and clearness in color separation. The liquid crystal display device includes a liquid crystal display module in which a liquid crystal layer and a color filter are formed between a pair of opposing transparent substrates and a front light is mounted to the front side of the liquid crystal display module. The color filter has a stripe pattern which is substantially perpendicular to the stripe pattern of the front light.

Claims

1. A liquid crystal display device comprising a liquid crystal display module including a front side, a liquid crystal layer, a color filter having a stripe pattern, a pair of opposing transparent substrates, and a front light having a stripe pattern, the liquid crystal layer and the color filter formed between the pair of opposing transparent substrates, and the front light mounted to the front side of the liquid crystal display module,

wherein the stripe pattern of the color filter is substantially perpendicular to the stripe pattern of the front light.

2. A liquid crystal display device according to

claim 1

, wherein an angle made by the stripe pattern of the color filter and the stripe pattern of the front light is in the range of 90±

10 degrees.

3. A liquid crystal display device according to

claim 1

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of grooves formed in a main surface thereof.

4. A liquid crystal display device according to claim 3, wherein each groove has a first inclined surface portion having a first length and a second inclined surface portion having a second length and the first length is smaller than the second length.

5. A liquid crystal display device according to

claim 1

, the front light further comprising a transparent light guide plate having a side end surface and a light source arranged on the side end surface.

6. A liquid crystal display device according to

claim 5

, further comprising a first transparent reflection preventing layer disposed on a surface of the front light opposing the grooves to reflect light directly from the light source towards the grooves and away from the liquid crystal.

7. A liquid crystal display device according to

claim 6

, further comprising a second transparent reflection preventing layer disposed on the grooves to reflect light from one of directly from the light source and from the first transparent reflection preventing layer towards the liquid crystal and away from the grooves.

8. A liquid crystal display device according to

claim 1

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of wedge-shaped grooves formed in a main surface thereof.

9. A liquid crystal display device according to

claim 8

, the wedge-shaped groove having two sides of unequal length.

10. A liquid crystal display device according to

claim 8

, the wedge-shaped grooves being formed successively.

11. A liquid crystal display device according to

claim 8

, the stripe pattern of the front light further comprising a surface substantially parallel to the transparent substrates formed between successive wedge-shaped grooves.

12. A liquid crystal display device according to

claim 1

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of striped recesses formed in a main surface thereof and shaped substantially as a part of a spherical surface.

13. A liquid crystal display device according to

claim 1

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of striped protrusions formed in a main surface thereof and shaped substantially as a part of a spherical surface.

14. A STN reflection-type liquid crystal display device according to

claim 1

.

15. An active matrix-type liquid crystal display device according to

claim 1

, further comprising a TFT element.

16. A liquid crystal display device comprising a liquid crystal display module including a front side, a liquid crystal layer, a color filter having a stripe pattern, a pair of opposing transparent substrates, and a front light having a stripe pattern, the liquid crystal layer and the color filter formed between the pair of opposing transparent substrates, and the front light mounted to the front side of the liquid crystal display module,

wherein an optimum angle exists between the stripe pattern of the color filter and the stripe pattern of the front light and the optimum angle is determined by a combination of a width of the color filter, a distance between the color filter and an adjacent color filter, a width of each of the grooves, and a distance between adjacent grooves.

17. A liquid crystal display device according to

claim 16

, wherein the optimum angle is in the range of 90±

10 degrees.

18. A liquid crystal display device according to

claim 16

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction and the stripe pattern of the front light comprising a plurality of grooves formed in a main surface thereof.

19. A liquid crystal display device according to

claim 18

, wherein each groove has a first inclined surface portion having a first length and a second inclined surface portion having a second length and the first length is smaller than the second length.

20. A liquid crystal display device according to

claim 16

, the front light further comprising a transparent light guide plate having a side end surface and a light source arranged on the side end surface.

21. A liquid crystal display device according to

claim 20

, further comprising a first transparent reflection preventing layer disposed on a surface of the front light opposing the grooves to reflect light directly from the light source towards the grooves and away from the liquid crystal.

22. A liquid crystal display device according to

claim 21

, further comprising a second transparent reflection preventing layer disposed on the grooves to reflect light from one of directly from the light source and from the first transparent reflection preventing layer towards the liquid crystal and away from the grooves.

23. A liquid crystal display device according to

claim 16

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of wedge-shaped grooves formed in a main surface thereof.

24. A liquid crystal display device according to

claim 23

, the wedge-shaped groove having two sides of unequal length.

25. A liquid crystal display device according to

claim 23

, the wedge-shaped grooves being formed successively.

26. A liquid crystal display device according to

claim 23

, the stripe pattern of the front light further comprising a surface substantially parallel to the transparent substrates formed between successive wedge-shaped grooves.

27. A liquid crystal display device according to

claim 16

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of striped recesses formed in a main surface thereof and shaped substantially as a part of a spherical surface.

28. A liquid crystal display device according to

claim 16

, the stripe pattern of the color filter comprising a plurality of stripe-shaped color filters arranged in a short side direction, and the stripe pattern of the front light comprising a plurality of striped protrusions formed in a main surface thereof and shaped substantially as a part of a spherical surface.

29. A STN reflection-type liquid crystal display device according to

claim 16

.

30. An active matrix-type liquid crystal display device according to

claim 16

, further comprising a TFT element.