LIQUID CRYSTAL DISPLAY DEVICE AND PROCESS FOR PRODUCING LIQUID CRYSTAL DISPLAY DEVICE

• US 20100014031A1
• Filed: 10/25/2007
• Published: 01/21/2010
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hara, Yoshihito, Imai, Hajime, Kitagawa, Hideki, Kikuchi, Tetsuo
• Granted Patent: US 8,421,967 B2
• Time in Patent Office: Days
• US Class Current: 349/113
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133555 Transflectors

Abstract

Transflective-type and reflection-type liquid crystal display devices having a high image quality are provided at low cost.

A liquid crystal display device according to the present invention is a liquid crystal display device having a reflection region for reflecting incident light toward a display surface, the reflection region including a Cs metal layer (metal layer), a gate insulating layer formed on the Cs metal layer, a semiconductor layer formed on the gate insulating layer, and a reflective layer formed on the semiconductor layer. On the surface of the reflective layer, a first recess and a second recess located inside the first recess are formed. The Cs metal layer and the semiconductor layer each have an aperture, and one of the first recess and the second recess is constituted by the aperture of the Cs metal layer, and the other is constituted by the aperture of the semiconductor layer.

Claims

1. A liquid crystal display device comprising a reflection region for reflecting incident light toward a display surface, wherein,

the reflection region includes a metal layer, an insulating layer formed on the metal layer, a semiconductor layer formed on the insulating layer, and a reflective layer formed on the semiconductor layer;

a first recess and a second recess located inside the first recess are formed on a surface of the reflective layer in the reflection region;

the metal layer has an aperture or a recess;

the semiconductor layer has an aperture; and

one of the first recess and the second recess is formed according to the aperture or recess of the metal layer, and the other of the first recess and the second recess is formed according to the aperture of the semiconductor layer.

2. The liquid crystal display device of claim 1, comprising a semiconductor region where a semiconductor device including a gate layer is formed, wherein

a tilting angle of a side face of the gate layer with respect to the display surface is larger than a tilting angle of a side face of the aperture or recess of the metal layer with respect to the display surface.

3. The liquid crystal display device of claim 1, wherein, on the surface of the reflective layer inside the first recess but outside the second recess, a flat surface which is generally parallel to the display surface is formed.

4. The liquid crystal display device of claim 1, wherein a side face of the aperture or recess of the metal layer includes a face whose tilting angle with respect to the display surface is 20 degrees or less.

5. The liquid crystal display device of claim 1, wherein an average tilting angle of a side face of the aperture or recess of the metal layer with respect to the display surface is 20 degrees or less.

6. The liquid crystal display device of claim 4, wherein a depth of the aperture of the metal layer is no less than 50 nm and no more than 1000 nm, and a width of the side face of the aperture of the metal layer as seen from a perpendicular direction with respect to the display surface is no less than 100 nm and no more than 4000 nm.

7. The liquid crystal display device of claim 4, wherein a depth of the recess of the metal layer is no less than 20 nm and no more than 1000 nm, and a width of the side face of the recess of the metal layer as seen from a perpendicular direction with respect to the display surface is no less than 100 nm and no more than 4000 nm.

8. The liquid crystal display device of claim 1, wherein,

the metal layer includes a first layer and a second layer formed on the first layer, the second layer being made of a material different from that of the first layer;

and

a bottom face of the recess of the metal layer is formed of the first layer.

9. The liquid crystal display device of claim 8, wherein the first layer is made of aluminum, and the second layer is made of titanium or titanium nitride.

10. The liquid crystal display device of claim 2, wherein the metal layer is formed by a photolithography and etching using halftone exposure, and the gate layer is formed by a photolithography and etching not using halftone exposure.

11. The liquid crystal display device of claim 1, wherein a third recess which is located inside the first recess is formed on the surface of the reflective layer.

12. The liquid crystal display device of claim 11, wherein the third recess is formed according to an opening or recess which is formed inside the recess of the metal layer.

13. The liquid crystal display device of claim 1, wherein the metal layer has a plurality of apertures or recesses.

14. The liquid crystal display device of claim 1, comprising:

a liquid crystal layer; and

an interlayer insulating layer and a pixel electrode interposed between the liquid crystal layer and the reflective layer, wherein a face of the pixel electrode facing the liquid crystal layer is formed flat without conforming to shapes of the first recess and the second recess of the reflective layer.

15. The liquid crystal display device of claim 1, wherein the metal layer includes a first metal layer and a second metal layer formed on the first metal layer, the second metal layer being made of a material different from that of the first metal layer;

the first metal layer and the second metal layer each have an aperture; and

the aperture of the first metal layer is formed inside the aperture of the second metal layer.

16. The liquid crystal display device of claim 15, wherein the first metal layer is made of aluminum, and the second metal layer is made of molybdenum.

17. The liquid crystal display device of claim 15, wherein the metal layer includes a third metal layer formed on the second metal layer, the third metal layer being made of a material different from those of the first metal layer and the second metal layer;

the third metal layer has an aperture; and

the aperture of the second metal layer is formed inside the aperture of the third metal layer.

18. The liquid crystal display device of claim 17, wherein the first metal layer is made of aluminum;

the second metal layer is made of molybdenum nitride; and

the third metal layer is made of molybdenum.

19. The liquid crystal display device of claim 1, wherein the metal layer has a composition which varies along a thickness direction of the metal layer.

20. The liquid crystal display device of claim 19, wherein the metal layer is made of molybdenum nitride, and a nitrogen content in the molybdenum nitride of the metal layer decreases toward the insulating layer.

21. A production method for a liquid crystal display device having a reflection region for reflecting incident light toward a display surface, comprising the steps of:

forming a metal layer having an aperture or a recess,

forming an insulating layer on the metal layer,

forming a semiconductor layer on the insulating layer, the semiconductor layer having an aperture, and

forming a reflective layer on the semiconductor layer, wherein,

on a surface of the reflective layer in the reflection region, a first recess and a second recess are formed, the second recess being formed inside the first recess; and

one of the first recess and the second recess is formed according to the aperture or recess of the metal layer, and the other of the first recess and the second recess is formed according to the aperture of the semiconductor layer.

22. The production method of claim 21, wherein,

the step of forming the metal layer comprises a step of forming a gate layer of the semiconductor device;

and

a tilting angle of a side face of the gate layer with respect to the display surface is made larger than a tilting angle of a side face of the aperture or recess of the metal layer with respect to the display surface.

23. The production method of claim 21, wherein, on the surface of the reflective layer inside the first recess but outside the second recess, a flat surface which is generally parallel to the display surface is formed.

24. The production method of claim 21, wherein a side face of the aperture or recess of the metal layer includes a face whose tilting angle with respect to the display surface is 20 degrees or less.

25. The production method of claim 21, wherein an average tilting angle of a side face of the aperture or recess of the metal layer with respect to the display surface is 20 degrees or less.

26. The production method of claim 24, wherein a depth of the aperture of the metal layer is no less than 50 nm and no more than 1000 nm, and a width of the side face of the aperture of the metal layer as seen from a perpendicular direction with respect to the display surface is no less than 100 nm and no more than 4000 nm.

27. The production method of claim 24, wherein a depth of the recess of the metal layer is no less than 20 nm and no more than 1000 nm, and a width of the side face of the recess of the metal layer as seen from a perpendicular direction with respect to the display surface is no less than 100 nm and no more than 4000 nm.

28. The production method of claim 21, wherein the step of forming the metal layer comprises a step of forming a first layer, a step of stacking a second layer on the first layer, and a step of forming an aperture in the second layer.

29. The production method of claim 28, wherein the first layer is made of aluminum, and the second layer is made of titanium or titanium nitride.

30. The production method of claim 22, wherein the metal layer is formed by a photolithography and etching using halftone exposure, and the gate layer is formed by a photolithography and etching not using halftone exposure.

31. The production method of claim 21, wherein a third recess which is located inside the first recess is formed on the surface of the reflective layer.

32. The production method of claim 31, wherein the third recess is formed according to an opening or recess which is formed inside the recess of the metal layer.

33. The production method of claim 21, wherein a plurality of apertures or recesses are formed in the metal layer.

34. The production method of claim 21, comprising a step of forming an interlayer insulating layer on the reflective layer and a step of forming a pixel electrode on the interlayer insulating layer, wherein,

a face of the pixel electrode is formed flat without conforming to shapes of the first recess and the second recess of the reflective layer.

35. The production method of claim 21, wherein the step of forming the metal layer comprises a step of forming a first metal layer and a step of forming on the first metal layer a second metal layer from a material which is different from that of the first metal layer;

an aperture is formed in each of the first metal layer and the second metal layer; and

the aperture of the first metal layer is formed inside the aperture of the second metal layer.

36. The production method of claim 35, wherein the first metal layer is made of aluminum, and the second metal layer is made of molybdenum.

37. The production method of claim 35, wherein,

the step of forming the metal layer comprises a step of forming on the second metal layer a third metal layer from a material which is different from those of the first metal layer and the second metal layer;

and

an aperture is formed in the third metal layer, the aperture of the second metal layer being located inside the aperture of the third metal layer.

38. The production method of claim 37, wherein the first metal layer is made of aluminum;

the second metal layer is made of molybdenum nitride; and

the third metal layer is made of molybdenum.

39. The production method of claim 21, wherein, in the step of forming the metal layer, the composition of the metal layer varies along a thickness direction of the metal layer.

40. The production method of claim 39, wherein the metal layer is made of molybdenum nitride;

and in the step of forming the metal layer, a nitrogen content in the molybdenum nitride of the metal layer decreases over time.