Liquid crystal device and electronic apparatus

• US 7,586,575 B2
• Filed: 09/21/2006
• Issued: 09/08/2009
• Est. Priority Date: 11/14/2005
• Status: Expired due to Fees

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Epson Imaging Devices Corporation (Seiko Group)
• Inventors: Nishimura, Joji, Higa, Masakatsu
• Primary Examiner(s): Font; Frank G
• Assistant Examiner(s): WONG, ERIC K
• Application Number:
  US11/524,254
• Publication Number:
  US 20070109473A1
• Time in Patent Office: 1,083 Days
• Field of Search: 349/114, 349/144, 349/146, 349/38
• US Class Current: 349/144
• 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 1/13712 the liquid crystal having negative dielectric anisotropy

Abstract

A liquid crystal device includes a pair of substrates and a liquid crystal layer held between the substrates and containing a liquid crystal having negative dielectric anisotropy. The liquid crystal layer includes subpixels, each including a plurality of transmissive display regions and a reflective display region that are arranged in a predetermined direction. The transmissive display regions are disposed at the ends of each subpixel in the direction in which the transmissive and reflective display regions are arranged. The liquid crystal device further includes a thickness-adjusting layer disposed between at least one of the substrates and the liquid crystal layer so that the liquid crystal layer is thinner in the reflective display region than in the transmissive display regions.

Claims

1. A liquid crystal device comprising:

a pair of substrates;

a liquid crystal layer held between the substrates and containing a liquid crystal having negative dielectric anisotropy, the liquid crystal layer including pixels, each pixel including three subpixels, each subpixel including a plurality of transmissive display regions and a reflective display region that are arranged in a predetermined direction, the transmissive display regions being disposed at the ends of each subpixel in the direction in which the transmissive and reflective display regions are arranged;

a thickness-adjusting layer disposed between at least one of the substrates and the liquid crystal layer so that the liquid crystal layer is thinner in the reflective display region than in the transmissive display regions;

wherein each subpixel is divided into three adjacent island portions, the island portions consisting of a center island portion and two outer island portions, the center island portion being formed in the reflective display region and each one of the outer island portions being formed in one of the transmissive display regions, such that the center island portion is sandwiched between the outer island portions, and the center island portion is electrically connected to each one of the adjacent outer island portions;

a plurality of signal lines disposed on one of the substrates so as to extend in the direction in which the transmissive and the reflective display regions are arranged; and

pixel-switching elements disposed in the reflective display regions of the subpixels to electrically connect the signal lines to the subpixels.

2. The liquid crystal device of claim 1, further comprising a pixel drive unit that drives the subpixels by applying signals of opposite polarities to the subpixels adjacent in the direction in which the transmissive and reflective display regions are arranged.

3. The liquid crystal device of claim 1, further comprising alignment control members corresponding to the individual island electrodes to control an alignment of the liquid crystal layer.

4. The liquid crystal device of claim 3, further comprising conductive connection portions that electrically connect the pixel-switching elements to the island electrodes in the reflective display regions, the conductive connection portions overlapping two-dimensionally with the alignment control members in the reflective display regions.

5. The liquid crystal device of claim 4, wherein the conductive connection portions and the alignment control members are disposed substantially in centers of the island electrodes in the reflective display regions.

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

two-terminal nonlinear pixel-switching elements disposed on one of the substrates in the reflective display regions of the subpixels, the pixel-switching elements being electrically connected to the island electrodes to electrically connect the signal lines to the subpixels; and

counter electrodes disposed on an other one of the substrates opposite the island electrodes with the subpixels defined therebetween, the counter electrodes being arranged in a stripe pattern.

7. The liquid crystal device of claim 6, further comprising a pixel drive unit that drives the subpixels by inputting signals of opposite polarities to the counter electrodes adjacent in the direction in which the signal lines extend.

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

a plurality of first signal lines disposed on one of the substrates so as to extend in the direction in which the transmissive and reflective display regions are arranged;

a plurality of second signal lines disposed on the substrate so as to extend across the first signal lines;

thin-film transistors disposed at positions on the one of the substrates which corresponds to intersections of the first and second signal lines in the reflective display regions of the subpixels, the thin-film transistors being electrically connected to the island electrodes to electrically connect the first signal lines to the subpixels; and

a common electrode disposed on the other one of the substrates opposite the island electrodes with the subpixels defined therebetween.

9. The liquid crystal device of claim 8, further comprising a pixel drive unit that drives the subpixels by inputting signals of opposite polarities to the adjacent second signal lines, the second signal lines being connected to the gates of the thin-film transistors.

10. The liquid crystal device of claim 8, further comprising a pixel drive unit that drives the subpixels by inputting signals of opposite polarities to any subpixel and the subpixels adjacent thereto in the direction in which the first signal lines extend and in the direction in which the second signal lines extend.

11. The liquid crystal device of claim 6, further comprising an interlayer insulating film disposed between the island electrodes and the pixel-switching elements on the one of the substrates on which the signal lines are disposed, the interlayer insulating film having a contact hole penetrating the film to electrically connect the pixel-switching elements to the island electrodes.

12. An electronic apparatus comprising the liquid crystal device of claim 1.

13. The liquid crystal device of claim 1, the subpixels further comprising adjacent island portions, tapered steps being formed at edges of the thickness-adjusting layer and located between the adjacent island portions.