Smectic liquid crystal color display screen

• US 4,593,978 A
• Filed: 03/19/1984
• Issued: 06/10/1986
• Est. Priority Date: 03/18/1983
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Mourey, Bruno, Hareng, Michel
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Gallivan, Richard F.
• Application Number:
  US06/590,644
• Time in Patent Office: 813 Days
• Field of Search: 350/336, 350/339 F, 350/350 S, 350/351
• US Class Current: 349/21
• CPC Class Codes: G02F 1/132 Thermal activation of liquid crystals exhibiting a thermo-optic effect
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/134336 Matrix

Abstract

Smectic liquid crystal display screens for displaying a color image. The object of the invention is to obtain a color image from filtering layers deposited on the electrodes of a matrix display screen, the configuration of the electrodes supporting these layers being such that it avoids phenomena of interlineation of the colors.

Claims

1. A smectic liquid crystal display screen of the matrix display type comprising a network of heating electrodes and a network of video electrodes surrounding a smectic liquid crystal layer, said screen restoring a color image from polychromatic radiation incident to the screen, said image being the resultant of the elementary display points formed by the intersection of the heating electrodes and the video electrodes, said screen also comprising means for selecting at least two primary colors of said radiation, said selection means being formed from filtering deposits placed at the elementary display points and supported by the electrodes of a least one of said networks, said filtering deposits being grouped in multiplets of primary colors, wherein the configuration of the electrodes and the arrangement of the multiplets are such that the filtering elements in the same alignment effect differentiated filtering so as to avoid alignment of the deposits of the same color.

2. The display screen as claimed in claim 1, wherein the primary colors are blue, red and green.

3. The display screen as claimed in claim 1, wherein the heating electrodes have a configuration in the form of broken lines comprising parts facing the video electrodes, said parts supporting filtering deposits, each heating electrode supporting deposits of the same color, each filtering deposit being of a different color from that of the deposits which surround it.

4. The display screen as claimed in claim 1, wherein said video electrodes are formed by a string of tongues connected together by thin conducting ribbons, said tongues each supporting a filtering deposit, each video electrode supporting deposits of the same color, each filtering deposit being of a different color from that of the deposits which surround it.

5. The display screen as claimed in claim 1, wherein said liquid crystal layer comprises a dichroic coloring agent in solution.