VARIABLE LIGHT TRANSMISSION DEVICE

• US 3,829,196 A
• Filed: 04/10/1973
• Issued: 08/13/1974
• Est. Priority Date: 01/27/1971
• Status: Expired due to Term

• Current Assignee: Satyendra Kumar Deb
• Original Assignee: Satyendra Kumar Deb
• Inventors: Deb, Satyendra Kumar
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US05/349,878
• Time in Patent Office: 490 Days
• Field of Search: 350/16R
• US Class Current: 359/275
• CPC Class Codes: G02F 1/1524 Transition metal compounds

Abstract

Variable light transmission device typically comprising a transition metal oxide layer sandwiched between a pair of electrode layers such as stannic oxide-coated glass and gold film. When an electric field is applied across the electrodes the device exhibits persistent coloration at ambient temperature.

Claims

2. The device of claim 1 wherein said electrochromic material and said electrodes are relatively thin layers and said electrochromic material is sandwicheD between said electrodes.

3. The device of claim 2 wherein at least one of said electrodes is substantially transparent.

4. The device fo claim 1 wherein said electrochromic material layer is a film of thickness in the range of about 0.1 to 100 microns.

5. The device of claim 1 wherein said electrochromic material contains at least one element of variable oxidation state.

6. The device of claim 1 wherein said electrochromic material is tungsten oxide, molybdenum oxide, niobium oxide, vanadium oxide, copper molybdate, copper stannate, or cobalt tungstate.

7. The device of claim 6 wherein the electrochromic material is doped with a metal.

8. The device of claim 1 wherein said electrochromic material is tungsten oxide.

9. The device of claim 1 wherein said electrochromic material is molybdenum oxide.

10. The device of claim 1 wherein said electromagnetic radiation is in the visible spectrum.

11. A device for providing variable absorption of electromagnetic radiation wherein said absorption may be varied from substantially no absorption to a desired degree of absorption and wherein said absorption may be reversed to said substantially non-absorptive state, further where said absorption may be fixed and be persistent at any point from the non-absorptive to the maximum absorptive state, which comprises a thin coherent layer of substantially only a solid, persistent electrochromic material, a pair of electrodes in contact with said material, and means for applying direct current voltage to said pair of electrodes to create an electric field across said material, said current being of a polarity which increases absorption, to increase absorption, for a time to obtain desired absorption, and then stopped, whereby said desired absorptive state persists;

and means to apply a current of a reverse polarity for a time to obtain a desired decrease in absorption, when such decrease is desired.