Transflective liquid crystal display with patterned optical layer

A liquid crystal display, transflective technology, used in the manufacture of such displays, in the field of patterned optical layers, can solve problems such as not, reduce contrast, image sharpness, blurring, etc., achieve easy manufacturing, avoid parallax problems, and optimize optical properties. Effect

Inactive Publication Date: 2007-02-28
KONINK PHILIPS ELECTRONICS NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this results in reduced contrast and image sharpness (blurring) and is not preferred

Method used

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  • Transflective liquid crystal display with patterned optical layer
  • Transflective liquid crystal display with patterned optical layer
  • Transflective liquid crystal display with patterned optical layer

Examples

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example 1

[0096] The substrate is provided with an alignment layer (rubbed polyimide or photo-alignment layer). A mixture of active LC materials including some (active) isomerizable chiral compounds is spin-coated on top of the alignment layer, which provides a layer of cholesteric ordered material with a cholesteric pitch less than or equal to 300 nm. The mixture may further include a reactive achiral LC, a non-isomerizable chiral compound and a photoinitiator. The layer can be irradiated in a desired pattern so that in the irradiated regions (where the layer has become nematic) the isomerizable chiral compound is switched and the cholesteric pitch is increased to infinity. This can be achieved if the helical twisting power (HTP) of the isomerizable chiral compound is zero at the time of the switch, or if the product of the HTP times the concentration of the isomerizable chiral compound is divided by the HTP and the HTP present in the mixture after the switch The products of the conce...

example 2

[0099] In this second approach, active chiral LC compounds or mixtures of (chiral) active LC materials are used which exhibit a chiral nematic (cholesteric) phase as well as a smectic A phase. The material or mixture is spin-coated on a substrate provided with an alignment layer. At low temperatures, the material is in the smectic A phase and in this way forms a uniaxial retardation layer after spin coating. Irradiating the layer according to the desired pattern will produce photopolymerization in the irradiated areas. Subsequently, the temperature is raised above the transition temperature from the smectic A phase to the cholesteric phase. In non-aggregated regions, the order will change from stratified to cholesteric, while the hierarchical order will remain in aggregated regions. Flood exposure at elevated temperature will freeze the cholesteric order by photopolymerization and produce a patterned optical layer.

example 3

[0101] Biregions are prepared for example according to the methods described by Imura et al., J Photopolym Sci Technol 8, p. 257 (1995) and Schadt et al., Nature 381, p. 212 (1996) or other methods known to those skilled in the art A photoaligned alignment film where the director orientation is determined by the polarization of the UV light used during the two-step UV exposure. Liquid crystal mixture RMM34 (available from Merck) was spin-coated on top of a dual domain light alignment film, eg LPP 265 CP layer. This achieves planar alignment of the active LC monomers. Exposure through a UV mask under a nitrogen atmosphere partially cross-linked the optical layer to freeze into the desired planar state (tilt angle of 0°) required for λ / 4 retardation in the reflective portion of the pixel. The optical layer is then annealed at elevated temperature for about 10 minutes. During the annealing step, the volatile surfactants in the liquid crystal mixture are evaporated, so that a sp...

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PUM

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Abstract

A transflective liquid crystal display comprising a plurality of pixels, each pixel comprising a liquid crystal layer (3) sandwiched between a front substrate (1) and a back substrate (2), and an optical layer (7) comprising a birefringent material, said pixels being divided into at least one transmissive (5) and at least one reflective subpixel (4), and said optical layer (7) being at least partly sandwiched between the liquid crystal layer (3) and one of said front substrate (1) or back substrate (2), and being patterned into domains (8, 9), each domain covering at least part of a reflective subpixel (4) or at least part of a transmissive subpixel (5).

Description

technical field [0001] The present invention relates to transflective liquid crystal displays with improved viewing angle dependence and contrast, and more particularly to patterned optical layers for improving viewing angle dependence and contrast of such displays. The invention also relates to methods of manufacturing such displays. Background technique [0002] Liquid crystal displays (LCDs) are used in a wide range of applications, such as televisions, computer monitors, handheld and robotic devices. The operation of LCDs is based on light modulation in a liquid crystal cell (LC cell), which consists of a liquid crystal layer sandwiched between a front substrate and a rear substrate. [0003] LCDs typically operate in one or both of two modes, transmissive and reflective. In a transmissive LCD, light from the backlight is modulated through the LC layer. Due to the backlight, transmissive LCDs are suitable for use in dark environments, such as indoors. An inherent dis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02F1/1335G02F1/13363G02B5/30
CPCG02F2413/09G02F2413/08G02F2202/40G02F2413/04G02F1/13363G02F1/133555G02F2001/133565G02F1/133565G02F1/133631G02F1/1335
Inventor S·J·鲁森达尔E·皮特斯J·鲁布B·M·I·范德詹德C·多尔恩坎普D·K·G·德博尔J·布鲁恩恩克
Owner KONINK PHILIPS ELECTRONICS NV
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