Reflective color LCD with color filters having particular transmissivity

• US 6,147,728 A
• Filed: 03/17/1997
• Issued: 11/14/2000
• Est. Priority Date: 07/17/1995
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Maeda, Tsuyoshi, Matsushima, Toshiharu, Okumura, Osamu, Okamoto, Eiji
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): TON, MINH TOAN T
• Application Number:
  US08/809,487
• Time in Patent Office: 1,338 Days
• Field of Search: 349/106, 349/96, 349/97, 349/113, 349/38, 349/112, 430/7
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night
• CPC Class Codes: G02F 2201/52 RGB geometrical arrangements
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G02F 2203/09 transflective

Abstract

A reflective type color liquid crystal device includes first and second substrates. Each substrate has an opposing inner surface. Each of the opposing inner surfaces has an electrode and forms a matrix-patterned dot group. Multiple liquid crystals are disposed between the substrates. The device also includes multiple color filters, including at least two different colors, at least one polarizing plate, and a reflective plate. At least one color of the color filters has a transmissivity of at least 50% for light of all the wavelengths in a range between 450 nm and 660 nm.

Claims

1. A reflective type color liquid crystal device, comprising:

first and second substrates, each substrate having an opposing inner surface;

a liquid crystal layer disposed between said substrates;

a plurality of color filters disposed on one of said substrates, including at least two different colors;

at least one polarizing plate disposed on said first substrate;

a reflective plate disposed on said second substrate; and

wherein said color filters have a transmissivity of at least 30% for light of all wavelengths in a range of 450 nm to 660 nm.

2. The reflective type color liquid crystal device according to claim 1, wherein,

the thickness of the second substrate is at least 200 μ

m.

3. The reflective type color liquid crystal device according to claim 2, wherein each substrate has an electrode, said electrodes form a matrix patterned dot group, and wherein

non-linear elements are provided corresponding to each dot of the matrix patterned dot group on the inner surface of the first or second substrate.

4. The reflective type color liquid crystal device according to claim 1, wherein, said color filters include a red system, a green system, and a blue system, and either of said red system or said blue system color filters is orange or cyan.

5. The reflective type color liquid crystal device according to claim 1, wherein, each substrate has an electrode, said electrodes form a matrix patterned dot group, and wherein each dot of the matrix patterned dot group has light-controllable areas and said color filters are provided on only a portion of the light-controllable areas in each dot of the matrix patterned dot group.

6. The reflective type color liquid crystal device according to claim 5, wherein, transparent layers are formed at substantially the same thickness as said color filters on areas other than the light-controllable areas having color filters provided thereon.

7. The reflective type color liquid crystal device according to claim 1, wherein, the first and second substrate form a matrix patterned dot group, and wherein said color filters are provided on only at least 1/2 of the dots of the matrix patterned dot group.

8. The reflective type color liquid crystal device according to claim 1, wherein each substrate has an electrode, said electrodes form a matrix patterned dot group, and wherein said color filters are arranged such that the colors of adjacent dots of the matrix patterned dot group are different.

9. The reflective type color liquid crystal device according to claim 1, wherein the first and second substrate form a matrix patterned dot group, and wherein said color filters are provided on all of the dots of the matrix patterned dot group.

10. The reflective type color liquid crystal device according to claim 9, wherein,

black masks are not provided on the outside of said dots, and color filters are provided that have the same or less absorption as the areas inside the dots.

11. The reflective type color liquid crystal device according to claim 1, wherein, color filters are provided on the outer surface of the second substrate.

12. The reflective type color liquid crystal device according to claim 1, wherein each substrate has an electrode, said electrodes form a matrix patterned dot group, and wherein

non-linear elements are provided corresponding to each dot on the inner surface of the first or second substrate, and are wired in a direction parallel to the short edges of the dots of the matrix patterned dot group.

13. The reflective type color liquid crystal device according to claim 1, wherein a drive surface area ratio is between 60% to 85%.

14. The reflective type color liquid crystal device according to claim 1, wherein,

said reflective plate has scattering properties such that 80% or more of light is reflected inside a 30°

cone centered on its positive direction of reflection when a beam of light is introduced therein.

15. The reflective type color liquid crystal device according to claim 1, wherein,

said reflective plate is a semi-transmissive reflective plate, and backlights are provided behind the reflective plate.

16. The reflective type color liquid crystal device according to claim 1, wherein,

said liquid crystals are nematic liquid crystals twisted 90°

, and two polarizing plates are disposed such that their transmissive axes are perpendicular to the rubbing directions of the adjacent substrates.

17. The reflective type color liquid crystal device according to claim 16, wherein,

the product Δ

nxd of the multiple refractivity Δ

n of the liquid crystals and the thickness d of the liquid crystal layer is between 0.34 μ

m to 0.52 μ

m.

18. The reflective type color liquid crystal device according to claim 1, wherein,

said liquid crystals are nematic liquid crystals twisted 90°

, and the device includes two polarizing plates and at least one phase variation film.

19. The reflective type color liquid crystal device according to claim 1, wherein,

said reflective plate is provided between the first and second substrates, and the device includes only one polarizing plate.

20. The reflective type color liquid crystal device according to claim 19, wherein,

said reflective plate is a mirror reflective plate, the second substrate is disposed adjacent the incident light and a scattering plate is provided on the outer surface of the second substrate.

21. The reflective type color liquid crystal device according to claim 20, wherein,

the liquid crystals on the metallic wiring are oriented in the same manner as the liquid crystals of the pixel area.

22. The reflective type color liquid crystal device according to claim 1, wherein,

the display is a normally white type.

23. The reflective type color liquid crystal device according to claim 1, wherein the first and second substrate form a matrix patterned dot group, and wherein one pixel includes one dot of the matrix patterned dot group.

24. An electronic apparatus comprising as a display the reflective type color liquid crystal device defined in claim 1.

25. The electronic apparatus according to claim 24, wherein,

the display is rotatable relative to the body such that ambient light can be reflected efficiently to the observer.

26. The reflective type color liquid crystal device according to claim 1, wherein active elements are provided on the inner surface of first or second substrates.

27. The reflective type color liquid crystal device according to claim 26, wherein active elements are provided on the inner surface of said second substrate.

28. The reflective type color liquid crystal device according to claim 27, wherein the pixel electrodes are provided on the said second substrate, each of said pixel electrode are connected with said active elements.

29. The reflective type color liquid crystal device according to claim 28, wherein the pixel electrodes combined scattering reflective plate.

30. The reflective type color liquid crystal device according to claim 26, wherein active elements are provided on the inner surface of said first substrate.

31. The reflective type color liquid crystal device according to claim 26, wherein said active elements are thin film transistor.

32. The reflective type color liquid crystal device according to claim 1, wherein said color filters have a transmissivity of at least 50% for light of all wavelengths in a range of 450 nm to 660 nm.

33. The reflective type color liquid crystal device according to claim 32, wherein said color filters have a transmissivity of at least 60% for light of all wavelengths in a range of 450 nm to 660 nm.

34. A reflective type color liquid crystal device, comprising:

first and second substrates, each substrate having an opposing inner surface;

a liquid crystal layer disposed between said substrates;

a plurality of color filters disposed on one of said substrates, including at least two different colors;

at least one polarizing plate disposed on said first substrate;

a reflective plate disposed on said second substrate; and

wherein at least one color of the color filters has a transmissivity of at least 50% for light of all wavelengths in a range of 450 nm to 660 nm.

35. The electronic apparatus according to claim 34, wherein

the color filters include cyan and red.

36. The electronic apparatus according to claim 34, wherein the color filters include green, red, and white color elements.

37. A reflective type color liquid crystal device, comprising:

first and second substrates, each substrate having an opposing inner surface;

a liquid crystal layer disposed between said substrates;

a plurality of color filters disposed on one of said substrates, including at least first and second color filters of different colors;

at least one polarizing plate disposed on said first substrate;

a reflective plate disposed on said second substrate; and

wherein a lowest transmissivity of the first color filter for light of wavelengths in the range of 450 nm to 660 nm is less than a lowest transmissivity of the second color filter for light of wavelengths in the range of 450 nm to 660 nm.

38. A reflective type color liquid crystal device, comprising:

first and second substrates, each substrate having an opposing inner surface;

a liquid crystal layer disposed between said substrates;

a plurality of color filters disposed on one of said substrates, including at least two different colors;

at least one polarizing plate disposed on said first substrate;

a reflective plate disposed on said second substrate;

wherein said color filters have first color filter, second color filter, and third color filter, said first color filter has a transmissivity of at least 70% for light of all wavelengths in a range of 570 nm to 660 nm, said second color filter has a transmissivity of at least 70% for light of all wavelengths in a range of 510 nm to 590 nm, said third color filter has a transmissivity of at least 70% for light of all wavelengths in a range of 450 nm to 520 nm.

39. The reflective type color liquid crystal device according to claim 38, wherein said first color filter has a transmissivity of at least 75% for light of all wavelengths in a range of 570 nm to 660 nm.

40. The reflective type color liquid crystal device according to claim 38, wherein said third color filter has a transmissivity of at least 75% for light of all wavelengths in a range of 450 nm to 520 nm.

41. The reflective type color liquid crystal device according to claim 38, wherein first color filter is a red color filter, second color filter is a green color filter, and third color filter is a blue color filter.

42. The reflective type color liquid crystal device according to claim 38, wherein the device includes a scattering plate.

43. The reflective type color liquid crystal device according to claim 38, wherein the device includes retardation film.