Browse Prior Art Database

Transmissive-Reflective Liquid Crystal Display

IP.com Disclosure Number: IPCOM000044393D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Dickerson, JA: AUTHOR [+2]

Abstract

This article describes a matrix-addressable liquid crystal display which operates in a reflective mode in high ambient light levels and a transmissive mode in low ambient light levels. Referring to the drawing, the display includes a conventional matrix-addressable smectic sandwich with a layer 10 of smectic material interposed between transparent substrates 12 and 14. Substrate 12 supports transparent, vertically-oriented electrodes 16 facing the layer 10. Substrate 14 includes horizontally-oriented, transparent electrodes 18 facing the layer 10. The smectic sandwich, which is per se conventional, is backed by a transparent electrode 20, an electroluminescent layer 22 and a second electrode 24. The electrode 24 is backed by a sheet 26 of light-reflecting aluminum. The entire assembly may be sealed by means of a glass layer 28.

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Transmissive-Reflective Liquid Crystal Display

This article describes a matrix-addressable liquid crystal display which operates in a reflective mode in high ambient light levels and a transmissive mode in low ambient light levels. Referring to the drawing, the display includes a conventional matrix-addressable smectic sandwich with a layer 10 of smectic material interposed between transparent substrates 12 and 14. Substrate 12 supports transparent, vertically-oriented electrodes 16 facing the layer 10. Substrate 14 includes horizontally-oriented, transparent electrodes 18 facing the layer 10. The smectic sandwich, which is per se conventional, is backed by a transparent electrode 20, an electroluminescent layer 22 and a second electrode 24. The electrode 24 is backed by a sheet 26 of light-reflecting aluminum. The entire assembly may be sealed by means of a glass layer 28. The electrodes 20 and 24 are connected to a source 30 of AC potential. The electrodes 16 and 18 in the smectic sandwich are selectively energized so as to be transparent in selected regions. For high ambient light levels, light is reflected from the aluminum layer
26. For low ambient light levels, the AC potential applied to electrodes 20 and 24 causes material 20 to phosphoresce. Under these conditions, the viewer can see the phosphorescent material through any clear region of the smectic sandwich.

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