Liquid crystal display unit and production method thereof

• US 20040027524A1
• Filed: 06/17/2003
• Published: 02/12/2004
• Est. Priority Date: 07/31/2000
• Status: Active Grant

• Current Assignee: Bishop Display Tech LLC (IP Edge LLC)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Ogawa, Shinji, Yamakita, Hiroyuki, Shiota, Akinori
• Granted Patent: US 7,414,682 B2
• Time in Patent Office: Days
• US Class Current: 349/129
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making

Abstract

An object of the present invention is to provide a liquid crystal display having a high luminance and a high contrast and a fabrication method thereof. To achieve the above object, a liquid crystal display of the present invention includes a liquid crystal panel for displaying an image by changing transmittance of a display light and one or more structures (151), (152) for dividing a pixel (103) of the liquid crystal panel into a plurality of domains (391), in which at least part of the structure (151) is constituted by a light-transmitting portion (151B) and a light-non-transmitting portion (151A).

Claims

1. A liquid crystal display comprising a liquid crystal panel for displaying an image by changing transmittance of a display light and one or more structures for dividing a pixel of the liquid crystal panel into a plurality of domains, characterized in that

at least one of the structures is partially constituted by a light-transmitting portion and a light-non-transmitting portion.

2. The liquid crystal display according to claim 1, wherein the structures comprise a light-transmitting layer serving as the light-transmitting portion and a light-non-transmitting layer serving as the light-non-transmitting portion formed on inner surfaces of a pair of substrates retaining liquid crystal therebetween in the liquid crystal panel.

3. The liquid crystal display according to claim 2, wherein the structure divides the pixel into a plurality of domains by controlling an alignment of the liquid crystal.

4. The liquid crystal display according to claim 3, wherein the light-transmitting layer and the light-non-transmitting layer of the structure are respectively constituted by a light-transmitting dielectric substance and a light-non-transmitting member.

5. The liquid crystal display according to claim 2, wherein the structure divides the pixel into a plurality of domains by applying a voltage to the liquid crystal.

6. The liquid crystal display according to claim 5, wherein the light-transmitting layer and the light-non-transmitting layer of the structure are respectively constituted by a light-transmitting electric conductor and a light-non-transmitting electric conductor.

7. The liquid crystal display according to claim 2, wherein the structure is formed such that the light-non-transmitting layer is surrounded by the light-transmitting layer when seen in a direction perpendicular to the liquid crystal panel.

8. The liquid crystal display according to claim 7, wherein the structure is formed such that the light-non-transmitting layer and the light-transmitting layer are layered in this order on the inner surfaces of the pair of substrates.

9. The liquid crystal display according to claim 2, wherein the light-non-transmitting layer of the structure is reflective.

10. A liquid crystal display of transversal electric field type comprising a liquid crystal panel in which liquid crystal is retained between a pair of substrates, a plurality of scanning signal lines and a plurality of video signal lines formed so as to define a plurality of pixels in matrix on an inner surface of one of the pair of substrates, and a pixel electrode and a common electrode formed so as to be aligned in each pixel, wherein an image is displayed on the liquid display panel by writing a video signal from the video signal line into the pixel electrode while sequentially selecting the pixel through the scanning signal line, characterized in that

at least one of the scanning signal lines, the video signal lines, the pixel electrode, and the common electrode is partially constituted by a light-transmitting conductive layer and a light-non-transmitting conductive layer.

11. The liquid crystal display according to claim 10, wherein a width of the light-transmitting conductive layer is narrower than a width of the light-non-transmitting conductive layer.

12. The liquid crystal display according to claim 11, wherein the width of the light-non-transmitting conductive layer is narrower than the width of the light-transmitting conductive layer by 1 μ

m or more.

13. The liquid crystal display according to claim 10, wherein the light-non-transmitting conductive layer and the light-transmitting conductive layer are layered in this order on the inner surface of the substrate.

14. The liquid crystal display according to claim 10, wherein an electric conductivity of the light-non-transmitting conductive layer is higher than an electric conductivity of the light-transmitting conductive layer.

15. The liquid crystal display according to claim 11, wherein the light-non-transmitting conductive layer is constituted by a plurality of layers having a different reflectance, and a layer closest to the liquid crystal has a lower reflectance than a layer closest to the substrate.

16. The liquid crystal display according to claim 15, wherein the layer of the light-non-transmitting conductive layer closest to the liquid crystal is constituted by an electric conductor having a higher reflectance than aluminum.

17. The liquid crystal display according to claim 15, wherein a blackening process is performed on a surface of the liquid crystal side of the light-non-transmitting conductive layer.

18. The liquid crystal display according to claim 10, wherein a light-blocking layer is formed on an inner surface of the other one of the pair of substrates so as to substantially overlap with the light-non-transmitting conductive layer when seen in a direction perpendicular to the liquid crystal panel.

19. The liquid crystal display according to claim 10, wherein a blackening process is performed on a surface of the liquid crystal side of the light-non-transmitting conductive layer.

20. A semi-transmitting liquid crystal display of transversal electric field type comprising a liquid crystal panel in which liquid crystal is retained between a pair of substrates, a plurality of scanning signal lines and a plurality of video signal lines formed so as to define a plurality of pixels in matrix on an inner surface of one of the pair of substrates, and a pixel electrode and a common electrode formed so as to be aligned in each pixel, wherein an image is displayed on the liquid display panel by writing a video signal from the video signal line into the pixel electrode while sequentially selecting the pixel through the scanning signal line, characterized in that

at least one of the scanning signal lines, the video signal lines, the pixel electrode, and the common electrode is partially constituted by a light-transmitting conductive layer and a light-non-transmitting conductive layer, and

the other of the scanning signal lines, the video signal lines, the pixel electrode, and the common electrode, which are not constituted by a light-transmitting conductive layer and a light-non-transmitting conductive layer, have a light diffusive surface.

21. The liquid crystal display according to claim 20, wherein a light-blocking layer is formed on an inner surface of the other one of the pair of substrates so as to substantially overlap with the scanning signal lines, the video signal lines, the pixel electrode, and the common electrode which have a light diffusive surface when seen in a direction perpendicular to the liquid crystal panel.

22. The liquid crystal display according to claim 20, wherein the light-non-transmitting conductive layer is constituted by an electric conductor having a higher reflectance than aluminum.

23. A liquid crystal display comprising an array substrate on an upper surface of which a common electrode, a pixel electrode, a scanning signal line, a video signal line, and a semiconductor switching device are formed, an opposing substrate disposed so as to be opposite to the upper surface of the array substrate, a liquid crystal panel having a liquid crystal layer disposed between the array substrate and the opposing substrate, and a reflecting face, wherein a light reflected on the reflecting face is transmitted through the liquid crystal panel, characterized in that

at least one electrode of the common electrode and the pixel electrode is constituted by an electrode portion and a wiring portion,

the electrode portion is at least partially constituted by a transparent electric conductor,

the electrode portion is formed in a layer separated by an insulating layer from a layer in which the scanning signal line is formed, and

the wiring portion is formed in the layer in which the scanning signal line is formed.

24. The liquid crystal display according to claim 23, wherein the common electrode and the pixel electrode are both constituted by a wiring portion and a comb-shaped electrode portion, and a width of the electrode portion at least partially constituted by a transparent electric conductor is different from a width of the other part of the electrode portion.

25. The liquid crystal display according to claim 24, wherein the width of the electrode portion partially constituted by a transparent electric conductor is larger than the width of the other part of the electrode portion.

26. The liquid crystal display according to claim 23, wherein the common electrode and the pixel electrode are both constituted by a wiring portion and a comb-shaped electrode portion, and widths of both of the common electrode portion and the pixel electrode portion are such that liquid crystal molecules above an electrode portion constituted by a transparent electric conductor can be modulated by an electric field generated between both of the electrode portions.

27. The liquid crystal display according to claim 26, wherein at least one of a width of each electrode portion of the common electrode and the pixel electrode and a spacing between both electrode portions of the common electrode and the pixel electrode is substantially equal to or smaller than a spacing between the array substrate and the opposing substrate.

28. The liquid crystal display according to claim 24, wherein a width of each electrode portion of the common electrode and the pixel electrode is 1 μ

m or more and 10 μ

m or less.

42. The liquid crystal display according to claim 23, wherein the semiconductor switching device is constituted by a channel etching type thin film transistor.

29. A liquid crystal display comprising an array substrate on an upper surface of which a common electrode, a pixel electrode, a scanning signal line, a video signal line, and a semiconductor switching device are formed, an opposing substrate disposed so as to be opposite to the upper surface of the array substrate, a liquid crystal panel having a liquid crystal layer disposed between the array substrate and the opposing substrate, and a reflecting face, wherein a light reflected on the reflecting face is transmitted through the liquid crystal panel, characterized in that

at least one of the common electrode, the pixel electrode, the scanning signal line, the video signal line, and the semiconductor switching device is at least partially constituted by a high reflectance electric conductor having a higher reflectance than aluminum.

30. The liquid crystal display according to claim 29, wherein the high reflectance electric conductor has a lower resistivity than aluminum, and at least one of the common electrode, the pixel electrode, the scanning signal line, and the video signal line is constituted by a single layer of the high reflectance electric conductor.

37. The liquid crystal display according to claim 29 or 35, wherein part of the common electrode and the video signal line are provided so as to overlap with one another with an insulating layer interposed therebetween when seen in a direction perpendicular to the array substrate.

38. The liquid crystal display according to any one of claims 29, 31, 32, and 35, wherein a light-blocking layer is provided on the substrate on which the pixel electrode is formed.

39. The liquid crystal display according to any one of claims 29, 31, 32, and 35, wherein a color filter is provided on the substrate on which the pixel electrode is formed.

40. The liquid crystal display according to claim 29, wherein a portion of the common electrode and a portion of the pixel electrode between which a substantially transversal electric field is generated are respectively formed so as to have at least one bent portion and at least one bent portion which are bent to conform in shape to one another in a pixel.

41. The liquid crystal display according to claim 40, comprising a light-blocking layer, wherein

the video signal line and the light-blocking layer are formed so as to have bent portions bent to conform in shape to the bent portions of the common electrode and the pixel electrode when seen in a direction perpendicular to the array substrate.

43. The liquid crystal display according to claim 29, wherein the semiconductor switching device is constituted by a thin film transistor using polysilicon.

44. The liquid crystal display according to any one of claims 29, 31, 32, and 35, wherein the higher reflectance than aluminum is more than 90%.

45. The liquid crystal display according to any one of claims 29, 31, 32, and 35, wherein the high reflectance electric conductor or the high reflectance layer is made of Ag-based material.

31. A liquid crystal display comprising a liquid crystal panel in which liquid crystal is retained between a pair of substrates, a plurality of scanning signal lines and a plurality of video signal lines formed so as to define a plurality of pixels in matrix on an inner surface of one of the pair of substrates, a pixel electrode formed in each pixel and a common electrode formed on an inner surface of the other one of the pair of substrates, wherein an image is displayed on the liquid display panel by writing a video signal from the video signal line into the pixel electrode while sequentially selecting the pixel through the scanning signal line, characterized in that

a high reflectance layer having a higher reflectance than aluminum is formed being separated by an insulating layer from at least one of the scanning signal lines, the video signal lines, and the pixel electrode and below them.

33. The liquid crystal display according to claim 31 or 32, wherein the high reflectance layer is formed so as to have substantially the same width as the scanning signal lines, the video signal lines, the pixel electrode, or the common electrode located above the high reflectance layer.

34. The liquid crystal display according to claim 31 or 32, wherein the high reflectance layer is formed so as to substantially overlap with the scanning signal lines, the video signal lines, the pixel electrode, or the common electrode located above the high reflectance layer when seen in a direction perpendicular to the liquid crystal panel.

32. A liquid crystal display of transversal electric field type comprising a liquid crystal panel in which liquid crystal is retained between a pair of substrates, a plurality of scanning signal lines and a plurality of video signal lines formed so as to define a plurality of pixels in matrix on an inner surface of one of the pair of substrates, and a pixel electrode and a common electrode formed so as to be aligned in each pixel, wherein an image is displayed on the liquid display panel by writing a video signal from the video signal line into the pixel electrode while sequentially selecting the pixel through the scanning signal line, characterized in that

a high reflectance layer having a higher reflectance than aluminum is formed being separated by an insulating layer from at least one of the scanning signal lines, the video signal lines, the pixel electrode, and the common electrode and below them.

35. A liquid crystal display comprising a liquid crystal panel having an array substrate on an upper surface of which a common electrode, a pixel electrode, a scanning signal line, a video signal line, and a semiconductor switching device are formed, an opposing substrate disposed so as to be opposite to the upper surface of the array substrate, and a liquid crystal layer disposed between the array substrate and the opposing substrate and a reflecting face formed below the liquid crystal panel, wherein a light reflected on the reflecting face is transmitted through the liquid crystal panel, characterized in that

at least one of the common electrode, the pixel electrode, the scanning signal line, the video signal line, and the semiconductor switching device has a plurality of layers which are non-transparent and having a different reflectance, and the plurality of layers are such that a layer closest to the liquid layer has a lower reflectance than a layer closest to the array substrate.

36. The liquid crystal display according to claim 35, wherein the layer closest to the array substrate is constituted by an electric conductor having a higher reflectance than aluminum.