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(12) United States Patent ao) Patent No.: us 6,791,640 Bi
Okamoto et al. (45) Date of Patent: Sep. 14,2004
(54) REFLECTION LIQUID CRYSTAL DISPLAY AND REFLECTION LIQUID CRYSTAL DISPLAY PROVIDED WITH BUILT-IN TOUCH PANEL AND COMPRISING THE SAME
(75) Inventors: Masayuki Okamoto, Kashiwa (JP);
Seiichi Mitsui, Kashiwa (JP); Takashi
Satoh, Tenri (JP)
(73) Assignee: Sharp Kabushiki Kaisha, Osaka (JP)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/403,487
(22) PCT Filed: Mar. 26, 1998
(86) PCT No.: PCT/JP98/01348
§ 371 (c)(1),
(2), (4) Date: Oct. 22, 1999
(87) PCT Pub. No.: WO98/48320 PCT Pub. Date: Oct. 29, 1998
(30) Foreign Application Priority Data
Apr. 23, 1997 (JP) 9-105518
(51) Int. CI.7 G02F 1/1335
(52) U.S. CI 349/113; 349/119
(58) Field of Search 349/113, 117,
349/118, 119, 96, 97, 98
(56) References Cited
U.S. PATENT DOCUMENTS
3,960,438 A 6/1976 Bonne et al.
(List continued on next page.) FOREIGN PATENT DOCUMENTS EP 0 079 044 5/1983
(List continued on next page.)
The present invention offers reflective color liquid crystal display devices with a high contrast ratio and eye-friendly multi-color display capability, and liquid crystal display devices incorporating a touch panel arranged therefrom, ol which the display is not adversely affected by the installation ol a pressure sensitive input device. In a reflective liquid crystal display device arranged from a light reflexible substrate (5) and a substrate (4); a liquid crystal layer (1) in which nematic liquid crystal having a positive dielectric anisotropy is sandwiched between the substrates (4) and (5); a first optical retardation compensator plate (8); a second optical retardation compensator plate (9); and a polarizer plate (10), (T) the retardation ol the optical retardation compensator plates (8 and 9) in the substrate normal direction, (2) the angle formed by the slow axes ol the optical retardation compensator plates (8 and 9) and either the transmission axis or the absorption axis ol the polarizer plate (10), (5) the twist angle ol the liquid crystal layer (1), (4) the product ol the birefringence difference ol the liquid crystal in the liquid crystal layer (1) and the thickness ol the liquid crystal layer, and (5) the angle formed by the alignment direction ol the liquid crystal molecules in a close proximity ol the substrate (4) and either the transmission axis or the absorption axis ol the polarizer plate are optimized.
14 Claims, 31 Drawing Sheets
E. Beynon et al, 1997 SID, L-34-L37 "Single Polariser Reflective Twisted Nematics."
Wu et al., Appl. Phys. Lett 68 (11), Mar. 11, 1996, pp. 1455-1457, "Mixed-Mode Twisted Nematic Liquid Crystal Cells for Reflective Displays."
A. Yariv et al., 1984, pp. 62-63, John Wiley & Sons, "Optical Waves in Crystals."
Hirakata et al., SID 1995 Digest, P-49, pp. 563-566, "A High-Contrast Wide-Viewing Angle Low-Twisted Nematic LCD Mode."
S. Palmer, Applied Optics, vol. 36, No. 10, Apr. 1,1997, pp. 2094-2100, "Liquid-Crystal Cell with a Wide Viewing Angle and a High Cell Contrast."
Wei, Chung-Kuang et al., Proceedings of the Fourth Asian Symposium on Information Display (ASID), pp. 25-28 (1997)—"A 10.4-IN Reflective Type TFT-LCD Using Mixed-Mode Twisted Nematics".
Pancharatnam, S., Proceedings of the Indian Academy of Science, vol. XLI, No. 4, Sec. A, pp. 130-144 (1995)— "Achromatic combinations of Birefringent Plates".
* cited by examiner