Liquid crystal display device and fabrication method thereof

• US 7,697,099 B2
• Filed: 11/04/2004
• Issued: 04/13/2010
• Est. Priority Date: 11/07/2003
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Nagae, Nobukazu, Kume, Yasuhiro, Yamada, Nobuaki, Tamai, Kazuhiko, Onishi, Noriaki, Kojima, Hiroaki, Kurihara, Takashi
• Primary Examiner(s): Nguyen; Dung T.
• Application Number:
  US10/980,867
• Publication Number:
  US 20050117108A1
• Time in Patent Office: 1,986 Days
• Field of Search: 349/139, 349129-130, 349155-156, 349/110, 349/138
• US Class Current: 349/138
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/133377 Cells with plural compartments or having plurality of liquid crystal microcells partitioned by walls, e.g. one microcell per pixel
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 1/133742 for homeotropic alignment
• CPC Class Codes: G02F 1/133776 having structures locally influencing the alignment, e.g. unevenness

Abstract

A liquid crystal display device including a first substrate 110a, a second substrate 110b placed to face the first substrate, a liquid crystal layer 120 interposed between the first and second substrates, a first electrode 111 formed on the first substrate, a second electrode 131 formed on the second substrate, an interlayer insulating film 115a placed between the first electrode and the first substrate, and a wall structure 115b formed integrally with the interlayer insulating film. The liquid crystal display device has a plurality of pixels each including the first electrode, the second electrode and the liquid crystal layer interposed between the first and second electrodes. A shading region surrounds each of the plurality of pixels, and the wall structure is placed regularly in the shading region. A groove structure 415a may be formed in place of the wall structure.

Claims

1. A liquid crystal display device comprising

a first substrate, a second substrate placed to face the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, a first electrode formed on the first substrate, a second electrode formed on the second substrate, an interlayer insulating film placed between the first electrode and the first substrate, and a wall structure formed integrally with the interlayer insulating film,

wherein the liquid crystal display device has a plurality of pixels each including the first electrode, the second electrode and the liquid crystal layer interposed between the first electrode and the second electrode, a shading region is provided to surround each of the plurality of pixels, and the wall structure is placed regularly in the shading region,

wherein the interlayer insulating film and the wall structure are formed of a single photosensitive resin film;

and

wherein the wall structure surrounds at least one of the pixels.

2. The liquid crystal display device of claim 1, further comprising a plurality of switching elements formed on the first substrate, each of the switching elements being electrically connected to the first electrode, wherein at least part of each of the switching elements is covered with the interlayer insulating film.

3. The liquid crystal display device of claim 1, wherein the first electrode included in each of the plurality of pixels includes a transparent electrode and a reflective electrode.

4. The liquid crystal display device of claim 1, wherein the wall structure has an inclined side face, and the first electrode extends up to on the side face.

5. The liquid crystal display device of claim 1, wherein the liquid crystal layer is a vertically aligned liquid crystal layer, and when at least a predetermined voltage is applied, at least one liquid crystal domain including liquid crystal molecules aligned in different directions is formed in the liquid crystal layer of each pixel.

6. The liquid crystal display device of claim 1, wherein the first electrode and/or the second electrode of each pixel have a plurality of openings and/or cuts formed at predetermined positions.

7. The liquid crystal display device of claim 6, wherein the first electrode and/or the second electrode of each pixel have at least two openings and at least one cut formed at predetermined positions.

8. The liquid crystal display device of claim 6, wherein the plurality of openings and/or cuts are formed in only the first electrode.

9. The liquid crystal display device of claim 6, wherein the liquid crystal layer is a vertically aligned liquid crystal layer, at least two liquid crystal domains each having axisymmetric alignment are formed in the liquid crystal layer of each pixel when at least a predetermined voltage is applied, and the center axes of the axisymmetric alignment of the at least two liquid crystal domains are formed in or near the plurality of openings.

10. The liquid crystal display device of claim 1, wherein the wall structure has walls isolated from each other with a wall gap.

11. The liquid crystal display device of claim 10, wherein the length of the wall gap existing along the circumference of one pixel is 40% or less of the length of the circumference of the pixel.

12. The liquid crystal display device of claim 1, wherein supports for defining the thickness of the liquid crystal layer are placed regularly in the shading region.

13. The liquid crystal display device of claim 12, wherein the wall structure has walls isolated from each other with wall gaps, and the supports are placed in the wall gaps.

14. The liquid crystal display device of claim 12, wherein a placement density D defined by WL×

N/PL, where WL (μ

m) is the diameter of the supports, N (pcs.) is the number of supports placed per regular unit (0.12 mm²), and PL (μ

m) is the pitch of the plurality of pixels in the longitudinal direction, satisfies the relationship 0.01≦

D≦

0.3.

15. The liquid crystal display device of claim 1, wherein the liquid crystal layer is a vertically aligned liquid crystal layer, and at least when a predetermined voltage is applied, at least one liquid crystal domain having axisymmetric alignment is formed in the liquid crystal layer of each pixel, and

the wall structure has an inclined side face, and the cross section of the wall structure and the interlayer insulating film in the plane vertical to the first substrate gives a continuous shape having its bottom in a region in which the center axis of axisymmetric alignment of the at least one liquid crystal domain is formed.

16. The liquid crystal display device of claim 1, wherein the wall structure has an inclined side face, and the tilt angle of the inclined side face with respect to the surface of the first substrate is 45°

or less.

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

a pair of polarizing plates placed to face each other via the first substrate and the second substrate; and

at least one biaxial optical anisotropic medium layer placed between the first substrate and/or the second substrate and the pair of polarizing plates.

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

a pair of polarizing plates placed to face each other via the first substrate and the second substrate; and

at least one uniaxial optical anisotropic medium layer placed between the first substrate and one of the pair of polarizing plates and/or between the second substrate and the other polarizing plate.

19. A liquid crystal display device comprising

a first substrate, a second substrate placed to face the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, a first electrode formed on the first substrate, a second electrode formed on the second substrate, and an interlayer insulating film placed between the first electrode and the first substrate, the interlayer insulating film having a groove structure,

wherein the liquid crystal display device has a plurality of pixels each including the first electrode, the second electrode and the liquid crystal layer interposed between the first electrode and the second electrode, a shading region is provided to surround each of the plurality of pixels, and the groove structure is formed regularly at least in the shading region,

wherein the liquid crystal layer is a vertically aligned type liquid crystal layer, and when at least a predetermined voltage is applied at least one liquid crystal domain including liquid crystal molecules aligned in different directions is formed in the liquid crystal layer of each pixel, and

wherein the groove structure defines a boundary of the at least one liquid crystal domain located near an outer edge of each pixel, and wherein the groove structure is formed along all sides of each of a plurality of the pixels.

20. The liquid crystal display device of claim 19, further comprising a plurality of switching elements formed on the first substrate, each of the switching elements being electrically connected to the first electrode, wherein at least part of each of the switching elements is covered with the interlayer insulating film.

21. The liquid crystal display device of claim 19, wherein the first electrode and/or the second electrode of each pixel have a plurality of openings and/or cuts formed at predetermined positions.

22. The liquid crystal display device of claim 21, wherein the first electrode and/or the second electrode of each pixel have at least two openings and at least one cut formed at predetermined positions.

23. The liquid crystal display device of claim 21, wherein the plurality of openings and/or cuts are formed in only the first electrode.

24. The liquid crystal display device of claim 21, wherein at least two liquid crystal domains each having axisymmetric alignment are formed in the liquid crystal layer of each pixel at least when a predetermined voltage is applied, and the center axes of the axisymmetric alignment of the at least two liquid crystal domains are formed in or near the plurality of openings.

25. The liquid crystal display device of claim 19, wherein at least two liquid crystal domains each having axisymmetric alignment are formed in the liquid crystal layer of each pixel at least when a predetermined voltage is applied, and the groove structure is also formed along the boundary between a pair of adjacent liquid crystal domains among the at least two liquid crystal domains.

26. The liquid crystal display device of claim 25, wherein an additional shading region is formed in each of the plurality of pixels, and the groove structure formed along the boundary is in the additional shading region.

27. The liquid crystal display device of claim 19, wherein the first electrode in each of the plurality of pixels includes a transparent electrode defining a transmission region and a reflective electrode defining a reflection region.

28. The liquid crystal display device of claim 27, wherein the groove structure is also formed along the boundary between the transmission region and the reflection region.

29. The liquid crystal display device of claim 19, further comprising:

a pair of polarizing plates placed to face each other via the first substrate and the second substrate; and

at least one biaxial optical anisotropic medium layer placed between the first substrate and one of the pair of polarizing plates and/or between the second substrate and the other polarizing plate.

30. The liquid crystal display device of claim 19, further comprising:

a pair of polarizing plates placed to face each other via the first substrate and the second substrate; and

at least one uniaxial optical anisotropic medium layer placed between the first substrate and one of the pair of polarizing plates and/or between the second substrate and the other polarizing plate.

31. A liquid crystal display device comprising

a first substrate, a second substrate placed to face the first substrate, a liquid crystal layer interposed between the first substrate and the second substrate, a first electrode formed on the first substrate, a second electrode formed on the second substrate, and an interlayer insulating film placed between the first electrode and the first substrate, the interlayer insulating film having a groove structure,

wherein the liquid crystal display device has a plurality of pixels each including the first electrode, the second electrode and the liquid crystal layer interposed between the first electrode and the second electrode, a shading region is provided to surround each of the plurality of pixels, and the groove structure is formed regularly at least in the shading region,

wherein the liquid crystal layer is a vertically aligned type liquid crystal layer, and when at least a predetermined voltage is applied at least one liquid crystal domain including liquid crystal molecules aligned in different directions is formed in the liquid crystal layer of each pixel,

wherein the groove structure defines a boundary of the at least one liquid crystal domain located near an outer edge of each pixel, and wherein the grooves surround the pixels, and

wherein a support structure extending between the substrates is provided in at least part of the groove.