Liquid crystal display and method of manufacturing the same

• US 20070273813A1
• Filed: 05/24/2007
• Published: 11/29/2007
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: Hidefumi Yoshida, Katsufumi Ohmuro, Kazuya Ueda, Kunihiro Tashiro, Masakazu Shibasaki, Tsuyoshi Kamada, Yasutoshi Tasaka
• Inventors: Shibasaki, Masakazu, Tashiro, Kunihiro, Ueda, Kazuya, Tasaka, Yasutoshi, Ohmuro, Katsufumi, Yoshida, Hidefumi, Kamada, Tsuyoshi
• Granted Patent: US 7,486,361 B2
• Time in Patent Office: Days
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes

Abstract

The invention relates to a transflective liquid crystal display capable of display in both of transmissive and reflective modes and a method of manufacturing the same and provides a transflective liquid crystal display which can achieve high display characteristics in both of the transmissive and reflective modes. A configuration is employed which includes a liquid crystal display panel having a pair of substrates and a liquid crystal layer sealed between the substrates, a pixel region including a reflective area having a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates, a backlight unit having a reflector and a light guide plate for reflecting the light which has entered the transmissive area from the side of the one of the pair of substrates and which has been transmitted by the area to cause the light to enter the transmissive area again from the side of the other of the pair of substrates, and a color filter layer formed only in the transmissive area of the pixel region.

Claims

1. A liquid crystal display comprising:

a pair of substrates provided opposite to each other;

a liquid crystal layer sealed between the pair of substrates;

a pixel region including a reflective area having a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates;

a reflective section for reflecting light which has entered the transmissive area from the side of the one of the pair of substrates and which has been transmitted by the transmissive area and for causing the light to enter the transmissive area again from the side of the other of the pair of substrates; and

a color filter layer formed only in the transmissive area of the pixel region.

2. A liquid crystal display according to claim 1, further comprising a backlight unit provided on the other of the pair of substrates, wherein the backlight unit includes a light guide plate and the reflective section that is provided behind the light guide plate.

3-11. -11. (canceled)

12. A liquid crystal display comprising:

a pair of substrates opposite to each other;

a liquid crystal layer sealed between the pair of substrates;

a transparent electrode which is formed on each of the pair of substrates and which applies a voltage to the liquid crystal layer; and

a pixel region having a reflective area including a reflector for reflecting light entering from the side of one of the pair of substrates and a transparent dielectric layer which is formed between the transparent electrode and the liquid crystal layer and which decreases an effective voltage applied to the liquid crystal layer and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates.

13. A liquid crystal display according to claim 12, wherein the transparent dielectric layer has a thickness in the range of 1 μ

m or more and 2 μ

m or less.

14. A liquid crystal display according to claim 12, further comprising a pillar spacer at least a part of which is formed of the same material as that of the transparent dielectric layer.

15. A liquid crystal display according to claim 12, wherein the transparent dielectric layer has light scattering properties.

16. A liquid crystal display according to claim 12, wherein the transparent dielectric layer is colored to serve as a color filter, the color being equal to a transmissive section in hue and being equal to or lower than the same in color purity.

27. A liquid crystal display according to claim 12, further comprising a resin layer provided on the thin film transistor, irregularities being formed at least in a part of the resin layer, wherein the reflector is formed on the irregularities and wherein at least a part of the surface of the reflector is inclined relative to a substrate surface.

17-18. -18. (canceled)

19. A method of manufacturing a liquid crystal display having a pixel region including a reflective area and a transmissive area, the method comprising the steps of;

forming a metal layer having a high reflectivity on a substrate and a metal layer having a low reflectivity on the same;

patterning the metal layer having a high reflectivity and the metal layer having a low reflectivity to form source and drain electrodes of a thin film transistor and a reflector provided in the reflective area;

forming an insulation film on the source and drain electrodes and the reflector; and

patterning the insulation film and simultaneously removing the metal layer having a low reflectivity on the reflector to expose the metal layer having a high reflectivity, thereby forming a reflective surface having a high optical reflectivity.

20. A method of manufacturing a liquid crystal display according to claim 19, wherein the step of patterning the insulation film is a step of forming a contact hole above the source electrode.

21-26. -26. (canceled)

28. A method of manufacturing a liquid crystal display having a reflector for reflecting light entering from the side of one of a pair of substrates and an irregularity forming pattern for forming irregularities on the reflector, the method comprising the steps of:

forming a conductor layer of the pattern for forming irregularities on the other of the pair of substrates at the simultaneously with a gate electrode of a thin film transistor;

forming a semiconductor layer on the conductor layer;

forming a dielectric layer on the semiconductor layer;

patterning the dielectric layer by performing back exposure using the conductor layer of the pattern for forming irregularities as a mask;

forming the pattern for forming irregularities having the conductor layer and the dielectric layer; and

forming the reflector on the pattern for forming irregularities.

29. A method of manufacturing a liquid crystal display according to claim 28, further comprising the steps of:

patterning the semiconductor layer at the same time when the dielectric layer is patterned; and

forming the pattern for forming irregularities having the conductor layer, the semiconductor layer and the dielectric layer.

30. A method of manufacturing a liquid crystal display according to claim 29, wherein the step of patterning the dielectric layer utilizes exposure from above the substrates in addition to the back exposure.

31. A liquid crystal display comprising:

a pair of substrates opposite to each other;

a liquid crystal layer sealed between the pair of substrates; and

a pixel region having a reflective area including a reflector for reflecting light entering from the side of one of the pair of substrates, the reflector being provided on the other of the pair of substrates, and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates,

wherein the reflector is provided at the periphery of the pixel region; and

wherein the transmissive area has a transparent pixel electrode which is provided at an opening of the reflector and which is formed above the reflector and electrically isolated from the reflector.

32. A liquid crystal display according to claim 31, wherein a cell thickness of the reflective area is substantially equal to or greater than a cell thickness of the transmissive area.

33. A liquid crystal display according to claim 31, wherein the reflector is provided on a bus line formed on the other of the pair of substrates.

34. A liquid crystal display according to claim 31, wherein the reflector is in an electrically floating state.

35. A liquid crystal display according to claim 31, wherein the reflector is at the same potential as that of a common electrode formed on either of the pair of substrates.

36. A liquid crystal display according to claim 31, wherein the reflector is at a ground potential.

37. A liquid crystal display according to claim 31, wherein the reflector is formed such that it is continuous between adjoining pixel regions.

38. A liquid crystal display according to claim 31, wherein the reflector is split between adjoining pixel regions.

39. A liquid crystal display according to claim 31, wherein the pixel electrode partially overlaps the reflector when viewed perpendicularly to a substrate surface.

40. A liquid crystal display according to claim 31, wherein an edge of the pixel electrode is aligned with an edge of the opening of the reflector when viewed perpendicularly to the substrate surface.

41. A liquid crystal display according to claim 31, wherein the edge of the pixel electrode is located inside the edge of the opening of the reflector when viewed perpendicularly to the substrate surface.

42. A liquid crystal display according to claim 31, wherein the edge of the pixel electrode is located outside the edge of the opening of the reflector when viewed perpendicularly to the substrate surface.

43. A liquid crystal display according to claim 31, wherein the pixel electrode includes a plurality of electrode units which are provided adjacent to each other with slits interposed between them and which are electrically connected to each other.

44. A liquid crystal display according to claim 43, wherein the reflector is further formed on the slits.

45. A liquid crystal display according to claim 43, wherein each of the electrode units has a solid electrode provided in a part of the electrode unit, and comb-shaped electrodes including a plurality of linear electrodes extending from the periphery of the solid electrode toward the periphery of the electrode unit.

46. A liquid crystal display according to claim 45, wherein the solid electrode is formed in the transmissive area.

47. A liquid crystal display according to claim 45, wherein the comb-shaped electrodes are formed such that they extend into the reflective area.

48. A liquid crystal display according to claim 47, wherein the comb-shaped electrodes in the reflective area include a smaller number of linear electrodes than the comb-shaped electrodes in the transmissive area.

49. A liquid crystal display according to claim 47, wherein each of gaps between adjoining comb-shaped electrodes formed by the comb-shaped electrodes in the reflective area is greater than each of gaps between adjoining comb-shaped electrodes formed by the comb-shaped electrodes in the transmissive area.

50. A liquid crystal display according to claim 43, wherein each of the electrode units has comb-shaped electrodes including a plurality of linear electrodes extending from a central section of the electrode unit toward the periphery of the electrode unit.

51. A liquid crystal display according to claim 50, wherein each of gaps between adjoining comb-shaped electrodes formed by the comb-shaped electrodes in the reflective area of the electrode unit is greater than each of gaps between adjoining comb-shaped electrodes formed by the comb-shaped electrodes in the transmissive area.

52. A liquid crystal display according to claim 50, wherein the comb-shaped electrodes in the reflective area of the electrode unit include a smaller number of linear electrodes than the comb-shaped electrodes in the transmissive area.

53. A liquid crystal display according to claim 43, wherein either of the pair of substrates has a protrusion for controlling alignment in a region associated with the central section of the electrode unit.

54. A liquid crystal display according to claim 31, further comprising a color filter layer formed under the reflector.

55. A liquid crystal display according to claim 54, further comprising a second color filter layer formed on either of the pair of substrates.

56. A liquid crystal display according to claim 54, further comprising a second color filter layer formed above the reflector.

57. A liquid crystal display according to claim 31, further comprising a color filter layer formed on either of the pair of substrates, wherein the color filter layer is removed in the reflective area.

58. A liquid crystal display according to claim 57, wherein the reflective area has a transparent resin layer having a thickness substantially equal to or smaller than the thickness of the color filter layer.

59. A liquid crystal display according to claim 31, comprising a pair of ¼

wave plates and a pair of polarizers provided outside the pair of substrates, respectively.

60. A liquid crystal display according to claim 31, comprising a light scattering layer formed outside either of the pair of substrates.

61. A liquid crystal display according to claim 60, wherein the light scattering layer is a film which scatters light entering in a predetermined direction.

62. A liquid crystal display comprising:

a pair of substrates provided opposite to each other;

a vertical alignment type liquid crystal layer sealed between the pair of substrates;

a pixel region having a reflective area including a reflector for reflecting light entering from the side of one of the pair of substrates and a transmissive area for transmitting light entering from the side of the other of the pair of substrates toward the one of the pair of substrates; and

an alignment controlling structure formed on the reflector and having light scattering power.

63. A liquid crystal display according to claim 62, wherein the reflector has a smooth surface.

64. A liquid crystal display according to claim 62, wherein the reflector is formed using a source electrode layer or a gate electrode layer.

65. A liquid crystal display according to claim 62, wherein at least a transparent electrode is formed between the reflector and the alignment controlling structure.

66. A liquid crystal display according to claim 62, wherein the alignment controlling structure is formed in the form of a frame, the display further comprising a point-like alignment controlling structure formed in a region of either of the pair of substrates corresponding to the interior of the frame.

72. A liquid crystal display according to claim 62, comprising a pair of ¼

wave plates and a pair of polarizers provided outside the pair of substrates, respectively.

67. A liquid crystal display comprising:

a pair of substrates provided opposite to each other;

a vertical alignment type liquid crystal layer sealed between the pair of substrates;

a pixel region which transmits light entering from the side of one of the pair of substrates; and

a reflective section having a parallax correcting function for reflecting light which has entered the pixel region from the side of the one of the pair of substrates and which has been transmitted by the region, thereby causing the light to enter the pixel region again from the side of the other of the pair of substrates.

68. A liquid crystal display according to claim 67, further comprising a backlight unit provided on the side of the other of the pair of substrate, wherein the backlight unit has a light guide plate and the reflector that is provided behind the light guide plate.

69. A liquid crystal display according to claim 67, wherein the reflective section has a surface on which irregularities are formed at a pitch different from that of pixel patterns.

70. A liquid crystal display according to claim 69, wherein the irregularities have a sectional shape in the form of consecutive cones or wedges.

71. A liquid crystal display according to claim 67, comprising a viewing angle control plate for scattering light entering in a predetermined direction provided between either of the pair of substrates and a polarizer.