Transflective liquid crystal display device

• US 7,675,592 B2
• Filed: 06/21/2007
• Issued: 03/09/2010
• Est. Priority Date: 07/07/2006
• Status: Expired due to Fees

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Sasaki, Tohru, Ochiai, Takahiro, Miyazawa, Toshio, Maki, Masahiro, Miyake, Hidekazu, Sonoda, Daisuke, Nakao, Takayuki
• Primary Examiner(s): KIANNI, KAVEH C
• Application Number:
  US11/812,770
• Publication Number:
  US 20080007679A1
• Time in Patent Office: 992 Days
• Field of Search: 349/114, 349/141
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

The manufacturing yield of transflective liquid crystal display devices is to be enhanced. In a transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel has a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates has: an active element; a first insulating film disposed in a higher layer than the electrode of the active element and having a first contact hole; a counter electrode disposed in a higher layer than the first insulating film; a reflective electrode disposed in the reflective part in a higher layer than the counter electrode; a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode and having a second contact hole; a pixel electrode disposed in a higher layer than the second insulating film; and an electroconductor formed in the first contact hole and electrically connected to the electrode of the active element, and the pixel electrode is electrically connected to the electroconductor via the second contact hole.

Claims

1. A transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel having a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates comprises:

an active element;

a first insulating film disposed in a higher layer than the electrode of the active element, the first insulating film having a first contact hole;

a counter electrode disposed in a higher layer than the first insulating film;

a reflective electrode disposed in the reflective part in a higher layer than the counter electrode;

a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode, the second insulating film having a second contact hole;

a pixel electrode disposed in a higher layer than the second insulating film; and

an electroconductor formed in the first contact hole, the electroconductor being electrically connected to the electrode of the active element, and

the pixel electrode is electrically connected to the electroconductor via the second contact hole, and

wherein the electroconductor is formed inside and outside the first contact hole all over.

2. The transflective liquid crystal display device, according to claim 1, wherein the electrode of the active element is formed of a material that is etched with the etchant or etching gas for the reflective electrode.

3. The transflective liquid crystal display device according to claim 1, wherein the pixel electrode is arranged superposed over the counter electrode;

and

the pixel electrode, the second insulating film and the counter electrode together constitute a holding capacitance.

4. The transflective liquid crystal display device according to claim 1, wherein each of the plurality of subpixels has the pixel electrode shared between the transmissive part and the reflective part;

the counter electrodes independent for the transmissive part and the reflective part; and

the driving voltages applied to the counter electrodes differ between the transmissive part and the reflective part.

5. A transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel having a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates comprises:

an active element;

a first insulating film disposed in a higher layer than the electrode of the active element, the first insulating film having a first contact hole;

a counter electrode disposed in a higher layer than the first insulating film;

a reflective electrode disposed in the reflective part in a higher layer than the counter electrode;

a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode, the second insulating film having a second contact hole;

a pixel electrode disposed in a higher layer than the second insulating film; and

an electroconductor formed in the first contact hole, the electroconductor being electrically connected to the electrode of the active element, and

the pixel electrode is electrically connected to the electroconductor via the second contact hole, and

wherein the one substrate has a third insulating film disposed in a higher layer than the electrode of the active element and in a lower layer than the first insulating film;

the third insulating film has a third contact hole; and

the electroconductor is electrically connected to the electrode of the active element via the first and third contact holes.

6. The transflective liquid crystal display device according to claim 5, wherein the electrode of the active element is formed of a material that is etched with the etchant or etching gas for the reflective electrode.

7. The transflective liquid crystal display device according to claim 5, wherein the pixel electrode is arranged superposed over the counter electrode;

and

the pixel electrode, the second insulating film and the counter electrode together constitute a holding capacitance.

8. The transflective liquid crystal display device according to claim 5, wherein each of the plurality of subpixels has the pixel electrode shared between the transmissive part and the reflective part;

the counter electrodes independent for the transmissive part and the reflective part; and

the driving voltages applied to the counter electrodes differ between the transmissive part and the reflective part.

9. A transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel having a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates comprises:

an active element;

a first insulating film disposed in a higher layer than the electrode of the active element, the first insulating film having a first contact hole;

a counter electrode disposed in a higher layer than the first insulating film;

a reflective electrode disposed in the reflective part in a higher layer than the counter electrode;

a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode, the second insulating film having a second contact hole;

a pixel electrode disposed in a higher layer than the second insulating film; and

an electroconductor formed in the first contact hole, the electroconductor being electrically connected to the electrode of the active element, and

the pixel electrode is electrically connected to the electroconductor via the second contact hole, and

wherein the electroconductor is formed at the same step as the counter electrode and electrically separated from the counter electrode.

10. The transflective liquid crystal display device according to claim 9, wherein the electrode of the active element is formed of a material that is etched with the etchant or etching gas for the reflective electrode.

11. The transflective liquid crystal display device according to claim 9, wherein the pixel electrode is arranged superposed over the counter electrode;

and

the pixel electrode, the second insulating film and the counter electrode together constitute a holding capacitance.

12. The transflective liquid crystal display device according to claim 9, wherein each of the plurality of subpixels has the pixel electrode shared between the transmissive part and the reflective part;

the counter electrodes independent for the transmissive part and the reflective part; and

the driving voltages applied to the counter electrodes differ between the transmissive part and the reflective part.

13. A transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel having a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates comprises:

an active element;

a first insulating film disposed in a higher layer than the electrode of the active element, the first insulating film having a first contact hole;

a counter electrode disposed in a higher layer than the first insulating film;

a reflective electrode disposed in the reflective part in a higher layer than the counter electrode;

a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode, the second insulating film having a second contact hole;

a pixel electrode disposed in a higher layer than the second insulating film; and

an electroconductor formed in the first contact hole, the electroconductor being electrically connected to the electrode of the active element, and

the pixel electrode is electrically connected to the electroconductor via the second contact hole, and

wherein the electrode of the active element contains in the surface thereof 1% or more of the material of the reflective electrode.

14. The transflective liquid crystal display device according to claim 13, wherein the electrode of the active element is formed of a material that is etched with the etchant or etching gas for the reflective electrode.

15. The transflective liquid crystal display device according to claim 13, wherein the pixel electrode is arranged superposed over the counter electrode;

and

the pixel electrode, the second insulating film and the counter electrode together constitute a holding capacitance.

16. The transflective liquid crystal display device according to claim 13, wherein each of the plurality of subpixels has the pixel electrode shared between the transmissive part and the reflective part;

the counter electrodes independent for the transmissive part and the reflective part; and

the driving voltages applied to the counter electrodes differ between the transmissive part and the reflective part.

17. A transflective liquid crystal display device including a liquid crystal display panel having a pair of substrates and a liquid crystal layer held between the pair of substrates, the liquid crystal display panel having a plurality of subpixels each having a transmissive part and a reflective part, wherein one of the pair of substrates comprises:

an active element;

a first insulating film disposed in a higher layer than the electrode of the active element, the first insulating film having a first contact hole;

a counter electrode disposed in a higher layer than the first insulating film;

a reflective electrode disposed in the reflective part in a higher layer than the counter electrode;

a second insulating film disposed in a higher layer than the counter electrode and the reflective electrode, the second insulating film having a second contact hole;

a pixel electrode disposed in a higher layer than the second insulating film; and

an electroconductor formed in the first contact hole, the electroconductor being electrically connected to the electrode of the active element, and

the pixel electrode is electrically connected to the electroconductor via the second contact hole, and

wherein the reflective part is provided with a phase differential plate.

18. The transflective liquid crystal display device according to claim 17, wherein the electrode of the active element is formed of a material that is etched with the etchant or etching gas for the reflective electrode.

19. The transflective liquid crystal display device according to claim 17, wherein the pixel electrode is arranged superposed over the counter electrode;

and

the pixel electrode, the second insulating film and the counter electrode together constitute a holding capacitance.

20. The transflective liquid crystal display device according to claim 17, wherein each of the plurality of subpixels has the pixel electrode shared between the transmissive part and the reflective part;

and

the driving voltages applied to the counter electrodes differ between the transmissive part and the reflective part.