Vertical alignment type LCD device with overlapping openings at opposed first and second electrodes and depression in interlayer insulating film corresponding to first electrode opening

• US 7,701,538 B2
• Filed: 05/01/2008
• Issued: 04/20/2010
• Est. Priority Date: 12/08/2003
• 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: Kume, Yasuhiro, Tamai, Kazuhiko, Onishi, Noriaki, Nagae, Nobukazu
• Primary Examiner(s): HEYMAN, JOHN S
• Application Number:
  US12/149,427
• Publication Number:
  US 20080218677A1
• Time in Patent Office: 719 Days
• Field of Search: 349/114, 349/129, 349/130
• US Class Current: 349/129
• 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 1/133753 with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/134318 having a patterned common electrode
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence

Abstract

The liquid crystal display device includes a first substrate 1110a, a second substrate 1110b placed to face the first substrate, and a liquid crystal layer 1120 interposed between the first substrate and the second substrate. The liquid crystal display device has a plurality of pixels each including a first electrode 1111 formed on the first substrate, a second electrode 1131 formed on the second substrate, and the liquid crystal layer interposed between the first electrode and the second electrode. The second electrode 1131 has at least one opening 1114 formed at a predetermined position in the pixel, the first substrate has a shading region in gaps between the plurality of pixels, and a wall structure 1115 is placed regularly on the surface of the first substrate facing the liquid crystal layer in the shading region. The liquid crystal layer has at least one liquid crystal domain having axisymmetric alignment formed when at least a predetermined voltage is applied, and the center axis of the axisymmetric alignment of the at least one liquid crystal domain is formed in or near the at least one opening.

Claims

1. A liquid crystal display device comprising a first substrate, a second substrate placed to face the first substrate, and a liquid crystal layer interposed between the first substrate and the second substrate,

wherein the liquid crystal display device has a plurality of pixels each including a first electrode formed on the first substrate, an interlayer insulating film formed between the first substrate and the first electrode, a second electrode formed on the second substrate, and the liquid crystal layer interposed between the first electrode and the second electrode, wherein the liquid crystal layer is a vertically aligned type liquid crystal layer,

the interlayer insulating film has at least one depression formed at a predetermined position, and the liquid crystal layer has at least one liquid crystal domain having axisymmetric alignment and including liquid crystal molecules tilted in directions defined with the at least one depression formed when at least a predetermined voltage is applied, and a center axis of the axisymmetric alignment is formed in or near the at least one depression,

wherein the first electrode has at least one opening defined therein, and the at least one opening comprises an opening formed at a position corresponding to the at least one depression,

wherein the second electrode has at least one other opening formed to substantially overlap with the at least one opening in the first electrode, and

wherein the center axis of the axisymmetric alignment is formed in or near the at least one other opening.

2. The liquid crystal display device of claim 1, wherein the plurality of pixels are arranged in a matrix, and the maximum inner diameter/width Dc of the at least one depression satisfies the relationship Dc<

0.35·

Ps where Ps is the pitch of the pixels in the shorter side direction.

3. The liquid crystal display device of claim 1, wherein the thickness Id of the interlayer insulating film and the depth h of the at least one depression satisfy the relationship h<

0.8·

Id.

4. The liquid crystal display device of claim 1, wherein the first electrode further has at least one cut.

5. The liquid crystal display device of claim 1, further including a wall structure formed integrally with the interlayer insulating film, and the wall structure is regularly placed around each of the plurality of pixels.

6. The liquid crystal display device of claim 5, wherein a shading region is provided to surround each of the plurality of pixels, and the wall structure is placed regularly in the shading region.

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

8. The liquid crystal display device of claim 1, wherein the first electrode includes a transparent electrode defining a transmission region and a reflective electrode defining a reflection region.

9. The liquid crystal display device of claim 8, wherein the at least one liquid crystal domain includes a liquid crystal domain having axisymmetric alignment formed in the transmission region.

10. The liquid crystal display device of claim 8, wherein the interlayer insulating film has a first region having a substantially flat surface and a second region having an uneven surface, the transparent electrode is formed in the first region, and the reflective electrode is formed in the second region.

11. 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.

12. 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.