Liquid crystal display including filter means with 10-70% transmittance in the selective reflection wavelength range

• US 6,597,419 B1
• Filed: 06/28/2000
• Issued: 07/22/2003
• Est. Priority Date: 07/02/1999
• Status: Expired due to Fees

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Nishiguchi, Kenji, Okada, Masakazu
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/605,457
• Time in Patent Office: 1,119 Days
• Field of Search: 349/104, 349/105, 349/106, 349/74
• US Class Current: 349/104
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/13476 in which at least one liquid crystal cell or layer assumes a scattering state
• CPC Class Codes: G02F 1/13478 based on selective reflection
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G02F 2201/343 cholesteric liquid crystal reflector

Abstract

Disclosed is a reflective type multilayer liquid crystal display having a blue liquid crystal light control layer, a green liquid crystal light control layer, and a red liquid crystal light control layer stacked in this order from a viewing side. The half width of a reflection spectrum of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side. Further, the maximum reflectance of the reflection spectrum of any of the liquid crystal light control layers is higher than that of the adjoining liquid crystal light control layer on the viewing side. In one embodiment, the chromaticity coordinate position, in the XYZ colorimetric system, of a color displayed when all the liquid crystal light control layers are in a state of reflecting at the maximum reflectance is present in a range within a distance of 0.02 from the chromaticity coordinate position of the standard white point.

Claims

1. A liquid crystal display comprising:

a plurality of liquid crystal light control layers each of which includes liquid crystal exhibiting a cholesteric phase and having a peak wavelength of a selective reflection wavelength range of a reflection spectrum in the visible wavelength range, the liquid crystal light control layers being stacked in such order that the peak wavelength of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side,

wherein a half width of the reflection spectrum of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side,

wherein a maximum reflectance of the reflection spectrum of any of the liquid crystal light control layers is higher than that of the adjoining liquid crystal light control layer on the viewing side, and

wherein the chromaticity coordinate position, in the XYZ colorimetric system, of a color displayed when all the liquid crystal light control layers are in a state of reflecting at the maximum reflectance is present in a range within a distance of 0.02 from the chromaticity coordinate position of the standard white point.

2. A liquid crystal display as claimed in claim 1, wherein the liquid crystal light control layers include, from the viewing side, a blue liquid crystal light control layer, a green liquid crystal light control layer, and a red liquid crystal light control layer.

3. A liquid crystal display as claimed in claim 2, further comprising:

a red filter layer disposed between the green liquid crystal light control layer and the red liquid crystal light control layer, the red filter layer being for absorbing at least part of light components in a wavelength range shorter than the selective reflection wavelength range of the red liquid crystal light control layer.

4. A liquid crystal display as claimed in claim 2, further comprising:

a yellow filter layer disposed between the blue liquid crystal light control layer and the green liquid crystal light control layer, the yellow filter layer being for absorbing at least part of light components in a wavelength range shorter than the selective reflection wavelength range of the green liquid crystal light control layer.

5. A liquid crystal display as claimed in claim 2, further comprising:

an ultraviolet cut filter disposed at the viewing side of the blue liquid crystal light control layer, the ultraviolet cut filter layer being for absorbing at least part of light components in a wavelength range shorter than the selective reflection wavelength range of the blue liquid crystal light control layer.

6. A liquid crystal display as claimed in claim 1, wherein each of the liquid crystal light control layers is sandwiched between substrates.

7. A liquid crystal display as claimed in claim 6, wherein a plurality of electrodes is formed on each of the substrates.

8. A liquid crystal display as claimed in claim 7, wherein the electrodes are made of an ITO.

9. A liquid crystal display as claimed in claim 6, wherein all of the substrates are transparent.

10. A liquid crystal display as claimed in claim 6, wherein one of the substrates that is situated farthest from the viewing side is black.

11. A liquid crystal display as claimed in claim 6, wherein at least one of the substrates is flexible.

12. A liquid crystal display as claimed in claim 1, wherein each of the liquid crystals of the liquid crystal light control layers is a chiral nematic liquid crystal.

13. A liquid crystal display as claimed in claim 1, further comprising:

filter means provided on the viewing side of or in at least one of the liquid crystal light control layers, the filter means being for absorbing at least part of light components in a wavelength range shorter than the selective reflection wavelength range of the at least one of the liquid crystal light control layers.

14. A liquid crystal display as claimed in claim 13, wherein the filter means is a filter layer provided on the electrodes that are provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers.

15. A liquid crystal display as claimed in claim 13, wherein said filter means comprises a coloring agent added in the at least one liquid crystal light control layer.

16. A liquid crystal display comprising:

a plurality of liquid crystal light control layers each of which includes liquid crystal exhibiting a cholesteric phase and having a peak wavelength of a selective reflection wavelength range of a reflection spectrum in the visible wavelength range, the liquid crystal light control layers being stacked in such order that the peak wavelength of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side; and

filter means provided on the viewing side of or in at least one of the liquid crystal light control layers,

wherein a transmittance of the filter means is 10 to 70% in the selective reflection wavelength range of the liquid crystal light control layer situated on the viewing side of the filter means.

17. A liquid crystal display as claimed in claim 16, wherein the liquid crystal light control layers include, from the viewing side, a blue liquid crystal light control layer, a green liquid crystal light control layer, and a red liquid crystal light control layer.

18. A liquid crystal display as claimed in claim 17, wherein the filter means is a red filter layer disposed between the green liquid crystal light control layer and the red liquid crystal light control layer.

19. A liquid crystal display as claimed in claim 17, wherein the filter means is a yellow filter layer disposed between the blue liquid crystal light control layer and the green liquid crystal light control layer.

20. A liquid crystal display as claimed in claim 16, wherein the filter means comprises a coloring agent added in the at least one liquid crystal light control layer.

21. A liquid crystal display as claimed in claim 16, wherein each of the liquid crystal light control layers is sandwiched between substrates.

22. A liquid crystal display as claimed in claim 21, wherein a plurality of electrodes is formed on each of the substrates.

23. A liquid crystal display as claimed in claim 22, wherein the filter means is a filter layer provided on the electrodes that are provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers.

24. A liquid crystal display as claimed in claim 22, wherein the filter means is a filter layer provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers, and the electrodes are provided on the filter layer.

25. A liquid crystal display as claimed in claim 22, wherein the electrodes are made of an ITO.

26. A liquid crystal display as claimed in claim 21, wherein all of the substrates are transparent.

27. A liquid crystal display as claimed in claim 21, wherein one of the substrates that is situated farthest from the viewing side is black.

28. A liquid crystal display as claimed in claim 21, wherein at least one of the substrates is flexible.

29. A liquid crystal display as claimed in claim 16, wherein each of the liquid crystals of the liquid crystal light control layers is a chiral nematic liquid crystal.

30. A liquid crystal display as claimed in claim 29, wherein the liquid crystal light control layers include, from the viewing side, a blue liquid crystal light control layer, a green liquid crystal light control layer, and a red liquid crystal light control layer.

31. A liquid crystal display as claimed in claim 30, wherein the filter means is a red filter layer disposed between the green liquid crystal light control layer and the red liquid crystal light control layer.

32. A liquid crystal display as claimed in claim 30, wherein the filter means is a yellow filter layer disposed between the blue liquid crystal light control layer and the green liquid crystal light control layer.

33. A liquid crystal display as claimed in claim 30, wherein the filter means is an ultraviolet cut filter disposed at the viewing side of the blue liquid crystal light control layer.

34. A liquid crystal display comprising:

a plurality of liquid crystal light control layers each of which includes liquid crystal exhibiting a cholesteric phase and having a peak wavelength of a selective reflection wavelength range of a reflection spectrum in the visible wavelength range, the liquid crystal light control layers being stacked in such order that the peak wavelength of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side; and

filter means provided on the viewing side of or in at least one of the liquid crystal light control layers, wherein the filter means absorbs light components in a shorter wavelength range from the peak wavelength of the liquid crystal light control layer situated not closer to the viewing side than the filter means to 1.3 to 1.5 times of the half width of the reflection spectrum of the liquid crystal light control layer situated not closer to the viewing side than the filter means,

wherein a transmittance of the filter means in the shorter wavelength range is 10 to 70%.

35. A liquid crystal display as claimed in claim 34, wherein each of the liquid crystal light control layers is sandwiched between substrates.

36. A liquid crystal display as claimed in claim 35, wherein a plurality of electrodes is formed on each of the substrates.

37. A liquid crystal display as claimed in claim 36, wherein the filter means is a filter layer provided on the electrodes that are provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers.

38. A liquid crystal display as claimed in claim 36, wherein the filter means is a filter layer provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers, and the electrodes are provided on the filter layer.

39. A liquid crystal display as claimed in claim 36, wherein the electrodes are made of an ITO.

40. A liquid crystal display as claimed in claim 35, wherein all of the substrates are transparent.

41. A liquid crystal display as claimed in claim 35, wherein one of the substrates that is situated farthest from the viewing side is black.

42. A liquid crystal display as claimed in claim 35, wherein at least one of the substrates is flexible.

43. A liquid crystal display as claimed in claim 34, wherein each of the liquid crystals of the liquid crystal light control layers is a chiral nematic liquid crystal.

44. A liquid crystal display comprising:

a plurality of liquid crystal light control layers each of which includes liquid crystal exhibiting a cholesteric phase and having a peak wavelength of a selective reflection wavelength range of a reflection spectrum in the visible wavelength range, the liquid crystal light control layers being stacked in such order that the peak wavelength of any of the liquid crystal light control layers is larger than that of the adjoining liquid crystal light control layer on the viewing side; and

filter means provided on the viewing side of or in at least one of the liquid crystal light control layers,

wherein the filter means absorbs light components in a shorter wavelength range of 120 to 150 nm from the peak wavelength of the liquid crystal light control layer situated not closer to the viewing side than the filter means, and

wherein a transmittance in the shorter wavelength range is 10 to 70%.

45. A liquid crystal display as claimed in claim 44, wherein the liquid crystal light control layers include, from the viewing side, a blue liquid crystal light control layer, a green liquid crystal light control layer, and a red liquid crystal light control layer.

46. A liquid crystal display as claimed in claim 45, wherein the filter means is a red filter layer disposed between the green liquid crystal light control layer and the red liquid crystal light control layer.

47. A liquid crystal display as claimed in claim 45, wherein the filter means is a yellow filter layer disposed between the blue liquid crystal light control layer and the green liquid crystal light control layer.

48. A liquid crystal display as claimed in claim 45, wherein the filter means is an ultraviolet cut filter disposed at the viewing side of the blue liquid crystal light control layer.

49. A liquid crystal display as claimed in claim 44, wherein each of the liquid crystal light control layers is sandwiched between substrates.

50. A liquid crystal display as claimed in claim 49, wherein a plurality of electrodes is formed on each of the substrates.

51. A liquid crystal display as claimed in claim 50, wherein the filter means is a filter layer provided on the electrodes that are provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers.

52. A liquid crystal display as claimed in claim 50, wherein the filter means is a filter layer provided on one of the substrates situated on the viewing side of the at least one of the liquid crystal light control layers, and the electrodes are provided on the filter layer.

53. A liquid crystal display as claimed in claim 50, wherein the electrodes are made of an ITO.

54. A liquid crystal display as claimed in claim 49, wherein all of the substrates are transparent.

55. A liquid crystal display as claimed in claim 49, wherein one of the substrates that is situated farthest from the viewing side is black.

56. A liquid crystal display as claimed in claim 49, wherein at least one of the substrates is flexible.

57. A liquid crystal display as claimed in claim 44, wherein each of the liquid crystals of the liquid crystal light control layers is a chiral nematic liquid crystal.