Liquid crystal display device and method for fabricating the same

• US 6,330,047 B1
• Filed: 03/10/2000
• Issued: 12/11/2001
• Est. Priority Date: 07/28/1997
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yamamoto, Akihiro, Shimada, Takayuki, Kubo, Masumi, Ishii, Yutaka, Ban, Atsushi, Narutaki, Yozo, Katayama, Mikio, Shimada, Yoshinori, Nishiki, Hirohiko, Yoshimura, Yoji
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/523,658
• Time in Patent Office: 641 Days
• Field of Search: 349/42, 349/44, 349/143, 349/147, 349/95, 349/111, 349/110, 349/138
• US Class Current: 349/147
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• 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 1/13712 the liquid crystal having negative dielectric anisotropy
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence

Abstract

A liquid crystal display device includes a first substrate, a second substrate, and a liquid crystal layer interposed between the first and second substrates, a plurality of pixel regions being defined by respective pairs of electrodes for applying a voltage to the liquid crystal layer, wherein each of the plurality of pixel regions includes a reflection region and a transmission region, and the first substrate includes, a transmission electrode through which light from a light source passes within the transmission region, and a reflection electrode by which ambient light is reflected within the reflection region, wherein the transmission electrode and the reflection electrode are electrically connected to each other in an interface area between the transmission region and the reflection region.

Claims

1. A liquid crystal display device comprising a first substrate, a second substrate, and a liquid crystal layer interposed between the first and second substrates, a plurality of pixel regions being defined by respective pairs of electrodes for applying a voltage to the liquid crystal layer,

wherein each of the plurality of pixel regions includes a reflection region and a transmission region, and

the first substrate includes,

a transmission electrode through which light from a light source passes within the transmission region, and

a reflection electrode by which ambient light is reflected within the reflection region,

wherein the transmission electrode and the reflection electrode are electrically connected to each other in an interface area between the transmission region and the reflection region.

2. A liquid crystal display device according to claim 1, further comprising an interlayer insulating film.

3. A liquid crystal display device according to claim 2, wherein the interlayer insulating film is located under both the transmission electrode and the reflection electrode.

4. A liquid crystal display device according to claim 3, wherein the reflection electrode is not flat.

5. A liquid crystal display device according to claim 3, wherein the interlayer insulating film is not flat.

6. A liquid crystal display device according to claim 2, wherein the reflection electrode is formed on tilted or concave and convex portions of the interlayer insulating film.

7. A liquid crystal display device according to claim 2, wherein the interlayer insulating film is provided to at least a portion between the transmission electrode and the reflection electrode.

8. A liquid crystal display device according to claim 7, wherein the interlayer insulating film is not present over a portion of the transmission region.

9. A liquid crystal display device according to claim 7, wherein the reflection electrode is formed in a position between the interlayer insulating film and an area through which the ambient light comes into the liquid crystal display device.

10. A liquid crystal display device according to claim 9, wherein the thickness of the liquid crystal layer in the reflection region is smaller than that of the liquid crystal layer in the transmission region.

11. A liquid crystal display device according to claim 10, wherein the thickness of the liquid crystal layer in the reflection region is about a ½

of that of the liquid crystal layer in the transmission region.

12. A liquid crystal display device according to claim 9, wherein the reflection electrode has concave and convex portions in a surface thereof.

13. A liquid crystal display device according to claim 9, wherein the interlayer insulating film has concave and convex portions in a surface thereof.

14. A liquid crystal display device according to claim 7, wherein the transmission electrode and the reflection electrode are electrically connected to each other in a region in which the interlayer insulating film is not formed.

15. A liquid crystal display device according to claim 14, further comprising a contact hole in which the transmission electrode and the reflection electrode are electrically connected to each other in addition to the electrical connection of the transmission electrode and the reflection electrode in the interface area between the transmission region and the reflection region.

16. A liquid crystal display device according to claim 14, wherein the transmission electrode and the reflection electrode are electrically connected to each other only in the interface area between the transmission region and the reflection region.

17. A liquid crystal display device according to claim 2, wherein the interlayer insulating film is made of a photosensitive resin.

18. A liquid crystal display device according to claim 2, wherein the interlayer insulating film is made of an organic resin film containing a light-shielding substance.

19. A liquid crystal display device according to claim 18, wherein the light-shielding substance contains a graphite.

20. A liquid crystal display device according to claim 2, wherein the interlayer insulating film is made of an organic resin film.

21. A liquid crystal display device according to claim 2, wherein the interlayer insulating film contains silicon nitride.

22. A liquid crystal display device according to claim 1, wherein the liquid crystal display device is an active matrix including a switching element.

23. A liquid crystal display device according to claim 22, wherein a thin film transistor is used as the switching element.

24. A liquid crystal display device according to claim 23, wherein a portion of a drain electrode of the thin film transistor and the transmission electrode are made of a same material.

25. A liquid crystal display device according to claim 24, wherein the same material is ITO.

26. A liquid crystal display device according to claim 23, further comprising a interlayer insulating film, wherein

the interlayer insulating film is located over at least a portion of a gate signal line of the thin film transistor, a source signal line of the thin film transistor, the thin film transistor, and a drain electrode of the thin film transistor.

27. A liquid crystal display device according to claim 26, wherein the reflection electrode is formed such that the reflection electrode entirely covers the thin film transistor through the interlayer insulating film interposed therebetween.

28. A liquid crystal display device according to claim 27, wherein

the pixel region is enclosed by a gate signal line and the source signal line of the thin film transistor, and

a peripheral portion of the reflection electrode overlaps the gate signal line and the source signal line enclosing the pixel region.

29. A liquid crystal display device according to claim 28, wherein the gate signal line and the source signal line have a light-shielding property.

30. A liquid crystal display device according to claim 1, wherein the transmission electrode is made of Indium Tin Oxide (ITO).

31. A liquid crystal display device according to claim 1, wherein the reflection electrode contains aluminum.

32. A liquid crystal display device according to claim 1, wherein a metallic layered film of aluminum and molybdenum is used as the reflection electrode.