Liquid crystal display device having first, second, and third transparent electrodes that form first and second storage capacitors

• US 8,253,873 B2
• Filed: 08/28/2008
• Issued: 08/28/2012
• Est. Priority Date: 09/04/2007
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated), Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Sasaki, Tohru, Ochiai, Takahiro
• Primary Examiner(s): Robinson, Mark
• Assistant Examiner(s): Lee, Paul
• Application Number:
  US12/230,417
• Publication Number:
  US 20090059110A1
• Time in Patent Office: 1,461 Days
• Field of Search: 349/114, 349/141, 349/38, 349/42, 349/43, 349/139, 349/147
• US Class Current: 349/38
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• 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
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/13629 Multilayer wirings
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors

Abstract

To form a sufficiently large storage capacitor, a liquid crystal display device includes a liquid crystal display panel having a first substrate, a second substrate, and a liquid crystal held between the first substrate and the second substrate, the liquid crystal display panel having multiple pixels arranged in matrix. The first substrate has, in a transmissive display area provided in each of the pixels, a laminated structure containing a first transparent electrode, a first insulating film, a second transparent electrode, a second insulating film, and a third transparent electrode which are laminated in this order. The first transparent electrode and the second transparent electrode are electrically insulated from each other and together form a first storage capacitor through the first insulating film, and the second transparent electrode and the third transparent electrode are electrically insulated from each other and together form a second storage capacitor through the second insulating film.

Claims

1. A liquid crystal display device comprising:

a liquid crystal display panel having a first substrate, a second substrate, and a liquid crystal held between the first substrate and the second substrate, the liquid crystal display panel having multiple pixels arranged in matrix, each of the multiple pixels having a thin film transistor; and

a transmissive display area provided in at least part of each of the pixels, having a laminated structure containing a first transparent electrode, a first insulating film, a second transparent electrode, a second insulating film, and a third transparent electrode which are laminated in this order with the first transparent electrode closest to the first substrate, wherein, for each pixel,

the first transparent electrode is formed in a rectangular shape and substantially covers the transmissive display area in a plan view,

the second transparent electrode is formed in a rectangular shape and substantially covers the transmissive display area in a plan view,

the first transparent electrode has a first region that does not overlap with the second transparent electrode,

the first region is disposed at first side of the thin film transistor in a pixel area,

the second transparent electrode has a second region which does not overlap with the first transparent electrode,

the second region is disposed at a second side of the thin film transistor that is opposite to the first side,

the first transparent electrode and the second transparent electrode are electrically insulated from each other and together form a first storage capacitor through the first insulating film, and

the second transparent electrode and the third transparent electrode are electrically insulated from each other and together form a second storage capacitor through the second insulating film.

2. A liquid crystal display device according to claim 1, wherein at least one of the first insulating film and the second insulating film is a laminate of multiple insulating films.

3. A liquid crystal display device according to claim 1, wherein the transmissive display area provided in at least part of each of the multiple pixels has a third insulating film, which is placed on the first substrate side of the first transparent electrode.

4. A liquid crystal display device according to claim 3, wherein the third insulating film is a laminate of multiple insulating films.

5. A liquid crystal display device according to claim 1, wherein

the first substrate has a reflective electrode in a reflective display area, which is provided in at least part of each of the multiple pixels, and

the reflective electrode is electrically connected to at least one of the first transparent electrode, the second transparent electrode, and the third transparent electrode.

6. A liquid crystal display device according to claim 1, wherein

the third transparent electrode has multiple comb-teeth electrodes, and

the liquid crystal display device generates an electric field that has a component parallel to a surface of the first substrate between the third transparent electrode and the second transparent electrode, and uses the electric field to drive a liquid crystal on the surface side of the third transparent electrode.

7. A liquid crystal display device according to claim 1, wherein

the third transparent electrode has a shape of a flat board with a slit, and

the liquid crystal display device generates an electric field that has a component parallel to a surface of the first substrate between the third transparent electrode and the second transparent electrode, and uses the electric field to drive a liquid crystal on the surface side of the third transparent electrode.

8. A liquid crystal display device according to claim 1, wherein

each of the multiple pixels has a fourth transparent electrode, which is placed on the second substrate side, and

the liquid crystal display device generates an electric field between the fourth transparent electrode and the third transparent electrode, and uses the electric field to drive a liquid crystal on the surface side of the third transparent electrode.

9. A liquid crystal display device according to claim 1, wherein

the third transparent electrode comprises a counter electrode,

the second transparent electrode comprises a pixel electrode, and

the first transparent electrode comprises a storage capacitor electrode.

10. A liquid crystal display device according to claim 9, wherein

the first insulating film is a laminate of a gate insulating layer and an interlayer insulating layer with the gate insulating layer placed closer to the first substrate,

the third transparent electrode is connected to a common electrode wiring line,

the second transparent electrode is connected to a first electrode of the thin film transistor through an opening formed in the interlayer insulating layer, and

the first transparent electrode is connected to a storage capacitor wiring line.

11. A liquid crystal display device according to claim 9, wherein

the first insulating film is a laminate of a gate insulating layer and an interlayer insulating layer with the gate insulating layer placed closer to the first substrate,

the first transparent electrode is connected to a common electrode wiring line,

the second transparent electrode is connected to a first electrode of the thin film transistor through an opening formed in the interlayer insulating layer, and

the third transparent electrode is connected to one of the first transparent electrode and the common electrode wiring line through openings formed in the gate insulating layer, the interlayer insulating layer, and the second insulating film.

12. A liquid crystal display device according to claim 9, wherein

the first transparent electrode is connected to a storage capacitor wiring line,

the second transparent electrode is connected to a first electrode of the thin film transistor, and

the third transparent electrode is connected to a common electrode wiring line.

13. A liquid crystal display device according to claim 9, wherein

the first transparent electrode is connected to a common electrode wiring line,

the second transparent electrode is connected to a first electrode of the thin film transistor, and

the third transparent electrode is connected to one of the first transparent electrode and the common electrode wiring line through openings formed in the first insulating film and the second insulating film.

14. A liquid crystal display device according to claim 9, wherein

the liquid crystal display device has an interlayer insulating layer formed above a first electrode of the thin film transistor,

the first transparent electrode is formed above the interlayer insulating layer,

the first transparent electrode is connected to a common electrode wiring line,

the second transparent electrode is connected to the first electrode of the thin film transistor through openings formed in the interlayer insulating layer and the first insulating film, and

the third transparent electrode is connected to one of the first transparent electrode and the common electrode wiring line through openings formed in the first insulating film and the second insulating film.

15. A liquid crystal display device according to claim 9, wherein

the liquid crystal display device has an interlayer insulating layer formed above a first electrode of the thin film transistor,

the first transparent electrode is formed above the interlayer insulating layer,

the third transparent electrode is connected to a common electrode wiring line,

the second transparent electrode is connected to the first electrode of the thin film transistor through openings formed in the interlayer insulating layer and the first insulating film,

the first transparent electrode is connected to an insular transparent electrode pattern which is formed within an opening in the first insulating film, and

the insular transparent electrode pattern is connected to the common electrode wiring line through an opening formed in the second insulating film.

16. A liquid crystal display device according to claim 1, wherein

each of the multiple pixels has a thin film transistor,

the first transparent electrode and the third transparent electrode comprise pixel electrodes, and

the second transparent electrode comprises a counter electrode.

17. A liquid crystal display device according to claim 16, wherein

the first transparent electrode is connected to a first electrode of the thin film transistor,

the second transparent electrode is connected to a common electrode wiring line, and

the third transparent electrode is connected to the first electrode of the thin film transistor through openings formed in the first insulating film and the second insulating film.

18. A liquid crystal display device according to claim 16, wherein

the first insulating film is a laminate of a gate insulating layer and an interlayer insulating layer with the gate insulating layer placed closer to the first substrate,

the first transparent electrode is connected to a first electrode of the thin film transistor through an opening formed in the gate insulating layer,

the second, transparent electrode is connected to a common electrode wiring line, and

the third transparent electrode is connected to the first electrode of the thin film transistor through openings formed in the interlayer insulating layer and the second insulating film.

19. A liquid crystal display device according to claim 16, wherein

the liquid crystal display device has an interlayer insulating layer formed above a first electrode of the thin film transistor,

the first transparent electrode is formed above the interlayer insulating layer,

the first transparent electrode is connected to the first electrode of the thin film transistor through an opening formed in the interlayer insulating layer,

the second transparent electrode is connected to a common electrode wiring line, and

the third transparent electrode is connected to the first transparent electrode through openings formed in the first insulating film and the second insulating film.

20. A liquid crystal display device according to claim 16, wherein

the first insulating film is a laminate of a gate insulating layer and an interlayer insulating layer with the gate insulating layer placed closer to the first substrate,

the first transparent electrode is connected to the third transparent electrode through openings formed in the gate insulating layer, the interlayer insulating layer, and the second insulating film,

the second transparent electrode is connected to a common electrode wiring line, and

the third transparent electrode is connected to a first electrode of the thin film transistor through openings formed in the interlayer insulating layer and the second insulating film.

21. A liquid crystal display device according to claim 10, wherein the common electrode wiring line and the storage capacitor wiring line are formed independently from each other.

22. A liquid crystal display device according to claim 12, wherein the common electrode wiring line and the storage capacitor wiring line are formed independently from each other.