VARIABLE LIGHT-FILTERING DEVICE

• US 3,774,988 A
• Filed: 06/21/1971
• Issued: 11/27/1973
• Est. Priority Date: 09/02/1969
• Status: Expired due to Term

• Current Assignee: Howard G. Rogers
• Original Assignee: Howard G. Rogers
• Inventors: Rogers, Howard G.
• Primary Examiner(s): Schonberg, David
• Assistant Examiner(s): Tokar, Michael J.
• Application Number:
  US05/155,112
• Time in Patent Office: 890 Days
• Field of Search: 350/147,150,157,160
• US Class Current: 359/275
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: F21S 41/135 Polarised
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G03C 1/705 Compositions containing chalcogenides, metals or alloys thereof, as photosensitive substances, e.g. photodope systems used as photoresist G03F7/004
• CPC Class Codes: G03G 17/02 with electrolytic development

Abstract

This invention relates to light filters employing redox compounds that are substantially light-transmitting in their oxidized state and capable of forming a stable colored free radical upon the addition of electrons. The colored free radical formed in response to the flow of electric current renders the device light-absorbing. To restore the original lighttransmitting properties, the colored free radical may be readily reoxidized, for example, by reversing the direction of current flow.

Claims

2. A device according to claim 1 including a light-polarizing sheet substantially coextensive with and having one surface in juxtaposition with the outer surface of one of said electrodes.

3. A device according to claim 1 including means for reversing the direction of current flow.

4. A device according to claim 3 including means for automatically predetermining said direction of current flow.

5. A device according to claim 1 wherein said layer contains an oxidizing agent.

6. A device according to claim 1 wherein said polymer is capable of functioning as its own electrolyte.

7. A device according to claim 6 wherein said polymer is the sole electrolyte.

8. A device according to claim 1 wherein said polymer is poly-N, n-butylene-4,4'"'"''"'"'-dipyridylium dibromide.