LIQUID CRYSTAL DEVICE AND ELECTRONIC EQUIPMENT

• US 20080100764A1
• Filed: 09/07/2007
• Published: 05/01/2008
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: HARUYAMA, Akihide
• Granted Patent: US 7,843,541 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• CPC Class Codes: G02F 1/133541 Circular polarisers
• CPC Class Codes: G02F 1/133555 Transflectors
• 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 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G02F 1/13731 based on a field-induced phase transition G02F1/13781 takes precedence

Abstract

A liquid crystal device including a liquid crystal layer having liquid crystal which demonstrates an optically isotropic property when no electric field is applied and demonstrates an optically anisotropic property which is proportional to the square of the electric field strength when electric field is applied, and a pair of substrates which sandwich the liquid crystal layer, including sub-pixel areas each including a reflective display area for reflective display and a transmissive display area for transmissive display; and first and second electrodes provided in both of the reflective display area and the transmissive display area, wherein the liquid crystal layer is driven by an electric field generated between the first electrode and the second electrode, and wherein the distance between the first electrode and the second electrode in the transmissive display area is smaller than the distance between the first electrode and the second electrode in the reflective display area.

Claims

1. A liquid crystal device including a liquid crystal layer having liquid crystal which is optically isotropic when no electric field is applied and shows optical anisotropy which is proportional to the square of an electric field which is applied to the liquid crystal, and a pair of substrates which sandwich the liquid crystal layer, comprising:

sub-pixels each including a reflective display area for reflective display and a transmissive display area for transmissive display; and

first and second electrodes provided in both of the reflective display area and the transmissive display area,

wherein the liquid crystal layer is driven by an electric field generated between the first electrode and the second electrode, and

wherein the distance between the first electrode and the second electrode in the transmissive display area is smaller than the distance between the first electrode and the second electrode in the reflective display area.

2. The liquid crystal device according to claim 1, wherein the distance between the first electrode and the second electrode in the reflective display area is set to approximately 1.4 times the distance between the first electrode and the second electrode in the transmissive display area.

3. The liquid crystal device according to claim 1, wherein at least one of the first electrode and the second electrode has the electrode width in the transmissive display area smaller than the electrode width in the reflective display area.

4. The liquid crystal device according to claim 1,

wherein the first electrode includes a plurality of first branch-shaped electrodes in the transmissive display area, and

wherein the second electrode includes a plurality of second branch-shaped electrodes in the transmissive display area.

5. The liquid crystal device according to claim 1, wherein at least one of the first electrode and the second electrode is branched into a plurality of pieces on one side, and the branched portion of the electrode is arranged in the transmissive display area.

6. The liquid crystal device according to claim 1, wherein the first electrode includes a plurality of first branch-shaped electrodes in the transmissive display area and the reflective display area, and the second electrode includes a plurality of second branch-shaped electrodes in the transmissive display area and the reflective display area.

7. The liquid crystal device according to claim 6, wherein the electrode width of the first branch-shaped electrode provided in the transmissive display area is smaller than the electrode width of the first branch-shaped electrode provided in the reflective display area.

8. The liquid crystal device according to claim 1, wherein first circularly polarizing plate is provided on the surface of the first substrate opposite from the liquid crystal layer, and

second circularly polarizing plate is provided on the surface of the second substrate opposite from the liquid crystal layer.

9. Electronic equipment comprising the liquid crystal device according to claim 1.