# US 6,295,113 B1 · Twisted nematic color liquid crystal display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,295,113 B1 - Document ID: US6295113B1 - Status: Granted - Kind: B1 - Application number: 09/312,947 - Filed: 1999-05-17 - Granted: 2001-09-25 - Earliest claimed: 1998-12-16 - Assignees: Picvue Electronics, Ltd. - Inventors: Chiu-Lien Yang - Web page: https://patentgrep.com/patent/US6295113B1 ## CPC - G02F 1/1396: {the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell (G02F1/141 takes precedence)} - 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)} - G02F 2202/40: Materials having a particular birefringence, retardation - G02F 2203/34: Colour display without the use of colour mosaic filters - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract A twisted nematic color liquid crystal display. The liquid crystal display comprises parallel glass substrates covered by a transparent electrode and an alignment film, a twisted nematic liquid crystal between the glass substrates, a retardation layer and polarizers. Between the glass substrates, a liquid crystal unit which forms the liquid crystal has a twist angle about 70 to about 180 about degree while free of an externally applying voltage. A product of anisotropy of refractive index for the twisted nematic liquid crystal Δn and the thickness d thereof, that is, Δn·d, is set in a range between about 1100 Å to about 2000 Å. Without using a passive device such as an external color light source or color filter, a multi-color or full color display is formed by an active controlling method of birefringence of electric field via applying a voltage on the transparent electrode. ## Claims ### Claim 1 A twisted nematic color liquid crystal display, comprising: a first glass substrate; a second glass substrate, disposed parallel to the first glass substrate; and a nematic liquid crystal, between the first and the second glass substrates, wherein nematic liquid crystal has a twist angle of about 70 degree to about 180 degree and a product of refractive index anisotropy and a thickness ranged from about 1100 Å to about 2000 Å. ### Claim 2 (depends on 1) The twisted nematic color liquid crystal display according to claim 1, comprising further: a first transparent electrode, disposed between the first glass substrate and the nematic liquid crystal; and the second transparent electrode, disposed between the second glass substrate and the nematic liquid crystal display. ### Claim 3 (depends on 2) The twisted nematic color liquid crystal display according to claim 2, comprising further: a first alignment film, disposed between the first electrode and the nematic liquid crystal display; and a second alignment film, disposed between the second electrode and the nematic liquid crystal display. ### Claim 4 (depends on 1) The twisted nematic color liquid crystal display according to claim 1, comprising further: a first polarizer, positioned over a second surface of the first glass substrate opposite to a first surface thereof having the nematic liquid crystal thereon; and a second polarizer, positioned over a second surface of the glass substrate opposite to a first surface thereof having the nematic liquid crystal thereon. ### Claim 5 (depends on 4) The twisted nematic color liquid crystal display according to claim 4, comprising further a reflection plate, wherein the second polarizer is between the reflection plate and the second glass substrate. ### Claim 6 (depends on 1) The twisted nematic color liquid crystal display according to claim 1, comprising further a retardation layer between the first glass substrate and the nematic liquid crystal. ### Claim 7 (depends on 6) The twisted nematic color liquid crystal display according to claim 6, wherein the retardation layer has a product of refractive index anisotropy and thickness ranged from about 1100 Å to about 2500 Å. ### Claim 8 (depends on 6) The twisted nematic color liquid crystal display according to claim 6, comprising further: a first polarizer, between the retardation layer and the nematic liquid crystal; and a second polarizer, between the glass substrate and the nematic liquid crystal. ### Claim 9 (depends on 8) The twisted nematic color liquid crystal display according to claim 8, comprising further a reflection plate, disposed on a side of the second polarizer opposite to the other side of the second polarizer facing the nematic liquid crystal. ### Claim 10 A twisted nematic color liquid crystal display, comprising: a first and a second polarizers; a nematic liquid crystal, between the first and the polarizers; a first glass substrate, between the first polarizer and the nematic liquid crystal; a second glass substrate, between the second polarizer and the nematic liquid crystal; a first alignment film, between the first glass substrate and the nematic liquid crystal; and a second alignment film, between the second glass substrate and the nematic liquid; wherein the nematic liquid crystal has a twist angle of about 70 degree to about 180 degree and a product of refractive index anisotropic and thickness of about 1100 Å to about 2000 Å. ### Claim 11 (depends on 10) The twist nematic color liquid crystal display according to claim 10, comprising further: a first transparent electrode, between the first glass substrate and the first alignment film; and a second transparent electrode, between the second glass substrate and the second alignment film. ### Claim 12 (depends on 10) The twist nematic color liquid crystal display according to claim 10, comprising further a retardation over the first polarization layer. ### Claim 13 (depends on 12) The twist nematic color liquid crystal display according to claim 12, wherein the retardation layer has a product refractive index anisotropy and thickness of about 1100 Å to about 2500 Å. ### Claim 14 (depends on 10) The twist nematic color liquid crystal display according to claim 10, comprising further a reflection plate over the second polarizer.