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Bistable twisted nematic mode reflective liquid crystal display

Imported: 23 Feb '17 | Published: 22 Oct '02

Sin-Doo Lee

USPTO - Utility Patents

Abstract

A liquid crystal display includes front and rear insulating substrates, each having inner and outer surfaces. The inner surface of the rear substrate faces the inner surface of the front substrate. A transparent electrode is formed on the inner surface of the front substrate, and a mirror electrode made with a reflective material is formed on the inner surface of the rear substrate. A polarizer is attached on the outer surface of the front substrate, and homogeneously aligning films are coated on the transparent and the mirror electrodes, followed by rubbing unidirectionally. A liquid crystal layer is interposed between the homogeneously aligning films on the two substrates. The liquid crystal layer is composed of a nematic liquid crystal material which has positive dielectric anisotropy and a chiral dopant to have a twisted structure. The molecular director in the liquid crystal layer is initially in the -twisted state. When a high reset voltage is applied to the liquid crystal display, the molecular director is rearranged in a homeotropically deformed state. A selection voltage lower than the reset voltage is applied to obtain one of the zero-twisted state and the -twisted state. Thereafter, a data voltage is applied for enhancing electro-optic characteristics.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a bistable twisted nematic (BTN) mode liquid crystal display (LCD) according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of liquid crystal molecules illustrating the principle of the BTN mode according to the embodiment of the present invention.

FIG. 3 shows the waveforms of the signals for driving the BTN mode LCD according to the embodiment of the present invention.

FIGS. 4A to

6B illustrate various optical configurations of the the BTN LCD according to the embodiment of the present invention.

FIGS. 7 to

9 are graphs showing the reflection of the BTN LCD as function of the selection voltage for the data voltages of 0, 1 and 2 V according to the embodiment of the present invention.

Claims

1. A liquid crystal display comprising:

2. A liquid crystal display comprising:

3. A liquid crystal display comprising: