Image display cell

• US 3,912,368 A
• Filed: 05/02/1974
• Issued: 10/14/1975
• Est. Priority Date: 05/04/1973
• Status: Expired due to Term

• Current Assignee: Cornelis Johannes Schoot, Hendrik Tjapko Van Dam, Johannes Jacobus Ponjee
• Original Assignee: Cornelis Johannes Schoot, Hendrik Tjapko Van Dam, Johannes Jacobus Ponjee
• Inventors: Ponjee, Johannes Jacobus, Van Dam, Hendrik Tjapko, Schoot, Cornelis Johannes
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Weisstuch, Aaron
• Application Number:
  US05/466,389
• Time in Patent Office: 530 Days
• Field of Search: 204/242,224R 350/16R 340/324R,378R,336CK,173R
• US Class Current: 359/272
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions

Abstract

The invention relates to an image display cell which forms an image which persists even if current no longer flows through the cell. The cell has at least two electrodes which are in contact with a cell liquid in which a colourless viologen salt (formula I) is dissolved. When a potential difference of at least 1.5 volts is applied across the electrodes the said salt is reduced to a coloured indissoluble compound which adheres to the cathode, thus colouring it and forming an image. At the anode, bromide is oxidized to bromine which complexes with a quarternary ammonium ion and precipitates on the anode.

Claims

1. IMAGE DISPLAY CELL HAVING A TRANSPARENT WALL PART AND CONTAINING AN AQUEOUS SOLUTION OF AN N,N- DISUBSTITUTED-4-4'"'"''"'"'BIPYRIDINUM SALT AS A REVERSIBLY REDUCIBLE REDOX SUBSTANCE AND OF A HALIDE AS A REVERSIBLY OXIDIZABLE REDOX SUBSTANCE, WHICH SOLUTION IS IN CONTACT WITH AT LEAST TWO INERT ELECTRODES. CHARACTERIZED IN THAT REVERSIBLY REDUCIBLE REDOX SUBSTANCE EITHER IS A COMPOUND OF THE FORMULA FOR THE FORMULA 1

2. Image display cell as claimed in claim 1, characterized in that a compound of the formula 1, where m 0, is used as the reversible reducible redox substance.

3. Image display cell as claimeD in claim 1 characterized in that each anode is at an angle to each cathode.

4. Image display cell as claimed in claim 1, characterized in that each anode is co-planar with each cathode.

5. Image display cell as claimed in claim 4, characterized in that an insoluble compound is dispersed in the cell liquid.

6. Image display cell as claimed in claim 5, characterized in that the cell has one or more reference electrodes.