METHOD, MATERIAL AND APPARATUS FOR INCREASING AND DECREASING THE TRANSMISSION OF RADIATION

• US 3,743,382 A
• Filed: 04/12/1971
• Issued: 07/03/1973
• Est. Priority Date: 04/12/1971
• Status: Expired due to Term

• Current Assignee: Research Frontiers Incorporated
• Original Assignee: Paul Rosenberg
• Inventors: Rosenberg, Paul
• Primary Examiner(s): Sikes, William L.
• Application Number:
  US05/133,205
• Time in Patent Office: 813 Days
• Field of Search: 350/160,161,267,266
• US Class Current: 359/296
• CPC Class Codes: G02F 1/172 based on a suspension of orientable dipolar particles, e.g. suspended particles displays

Abstract

A light control valve is disclosed having certain fluid suspensions therein which when activated increase the transmission of radiation through the valve in one part of the electromagnetic spectrum and decrease the transmission in another part of the spectrum.

Claims

1. A light valve for controlling the transmission of radiation in the electromagnetic spectrum comprising:

a cell having front and rear wall sections spaced apart a distance which is small compared to the lateral dimensions of the sections a fluid suspension in said cell of minute particles dispersed therein capable of having their orientation changed by the application of an electric field to the suspension to change the transmission of radiation through the suspension means for applying an electric field to the suspension between said wall sections in a direction substantially parallel to the direction of transmission of radiation through the suspension and substantially perpendicular to said wall sections, and said suspension being characterized in that it is responsive to said field applied in said direction to decrease the level of transmission of radiation therethrough, in part of the electromagnetic spectrum, below the level of transmission of radiation in this part of the spectrum when said field is not applied to the suspension and to simultaneously increase the level of transmission of radiation therethrough, in another part of the electromagnetic spectrum, above the level of transmission of radiation in this other part of the spectrum when said field is not applied to the suspension.

2. The light valve of claim 1 wherein the minute particles comprise titanium dioxide.

3. The light valve of claim 1 wherein the minute particles comprise iron oxide.

4. The light valve of claim 1 wherein the minute particles comprise cobalt aluminate.

5. The light valve of claim 1 wherein the part of the electromagnetic spEctrum where the level of transmission is decreased and the part of the electromagnetic spectrum where the level of transmission is increased are both in the visible section of the electromagnetic spectrum.

6. The light valve of claim 1 wherein filter means are provided to attenuate the light transmitted through the light valve in that portion of the visible spectrum where the level of transmission of radiation is increased in response to an applied electric field.

7. The light valve of claim 1 wherein filter means are provided to attenuate the light transmitted through the light valve in that portion of the visible spectrum where the level of transmission of radiation is decreased in response to an applied electric field.

8. A material for controlling the transmission of radiation in the electromagnetic spectrum comprising a fluid suspension including:

a suspending medium and a plurality of minute particles dispersed therein capable of having their orientation changed by the application of an electric field to the suspension to change the transmission of radiation through the suspension, said suspension being characterized in that it is responsive to said field applied in a direction substantially parallel to the direction of transmission of radiation through the suspension to decrease the level of transmission of radiation therethrough, in part of the electromagnetic spectrum, below the level of transmission of radiation in this part of the spectrum, when said field is not applied to the suspension, and to simultaneously increase the level of transmission of radiation therethrough, in another part of the electromagnetic spectrum, above the level of transmission of radiation in this other part of the spectrum when the field is not applied to the suspension.

9. The material of claim 8 wherein the minute particles comprise titanium dioxide.

10. The material of claim 8 wherein the minute particles comprise iron oxide.

11. The material of claim 8 wherein the minute particles comprise cobalt aluminate.

12. The material of claim 8 wherein the part of the electromagnetic spectrum where the level of transmission is decreased and the part of the electromagnetic spectrum where the level of transmission is increased are both in the visible section of the electromagnetic spectrum.