Multilayer light modulator

• US 8,004,747 B2
• Filed: 02/15/2011
• Issued: 08/23/2011
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Frazier, Gary A.
• Primary Examiner(s): Spector; David N
• Application Number:
  US13/027,790
• Publication Number:
  US 20110134507A1
• Time in Patent Office: 189 Days
• Field of Search: 345/107, 359/260, 359/296, 359/321, 359/579, 359/589
• US Class Current: 359/296
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/172 based on a suspension of orientable dipolar particles, e.g. suspended particles displays
• CPC Class Codes: G02F 1/21 by interference

Abstract

A method in accordance with particular embodiments includes receiving an electrical control signal. The method further includes adjusting a reflectance of a light modulating stack comprising a plurality of layers by changing the relative location of a plurality of electrophoretic particles with respect to the remainder of the light modulating stack. The method additionally includes receiving light waves from a light source. The method also includes converting the electrical control signal into a modulated optical signal that selectively switches between reflecting or absorbing at least a portion of the light waves.

Claims

1. A method comprising:

receiving an electrical control signal;

adjusting a reflectance of a light modulating stack comprising a plurality of layers by changing the relative location of a plurality of electrophoretic particles with respect to the remainder of the light modulating stack;

receiving light waves from a light source; and

converting the electrical control signal into a modulated optical signal that selectively switches between reflecting or absorbing at least a portion of the light waves.

2. The method of claim 1, wherein receiving an electrical control signal comprises receiving an electrical control signal indicating the reflectance of the light modulating stack is to produce a modulating optical signal of a predetermined pattern.

3. The method of claim 1, wherein adjusting the reflectance of the light modulating stack comprises:

applying a first voltage causing the electrophoretic particles to substantially cover a first surface of a first layer of the plurality of layers of the light modulating stack; and

applying a second voltage causing the electrophoretic particles to substantially cover a second surface of a second layer of the plurality of layers of the light modulating stack.

4. The method of claim 1, wherein the electrical control signal varies over time.

5. The method of claim 1, wherein adjusting the reflectance of the light modulating stack comprises adjusting the reflectance of the light modulating stack at least 100 times per second.

6. The method of claim 1, wherein adjusting the reflectance of the light modulating stack comprises adjusting a bias applied to at least one layer of the light modulating stack.

7. The method of claim 6, wherein upon the reflectance being adjusted, the bias is no longer applied to the light modulating stack.

8. The method of claim 1, wherein adjusting the reflectance of the light modulating stack comprises creating a layer of electrophoretic particles against an inner surface of one layer of the plurality of layers of the light modulating stack.

9. The method of claim 8, further comprising maintaining the layer of electrophoretic particles until the electrical control signal indicates a change in the reflectance of the light modulating stack.

10. A method comprising:

receiving light waves from a light source;

receiving a time varying electrical control signal, the time varying electrical control signal comprising control information indicative of a first reflectance at a first time and a second reflectance at a second time;

applying at the first time a first voltage causing a plurality of electrophoretic particles to substantially cover a first surface of a first layer of a light modulating stack, the light modulating stack reflecting at least a portion of the light waves; and

applying at the second time a second voltage causing the plurality of electrophoretic particles to substantially cover a second surface of a second layer of the plurality of layers of the light modulating stack, the light modulating stack absorbing at least a portion of the light waves.

11. The method of claim 10, wherein the time varying signal varies at a video rate.

12. The method of claim 10, further comprising, between the first time and the second time, removing the first voltage, the first surface remaining substantially covered by the plurality of electrophoretic particles until the second time.

13. The method of claim 10, wherein receiving a time varying electrical control signal comprises receiving a time varying electrical control signal indicating a first reflectance at a first time and a second reflectance at a second time, the first and second reflectance producing a modulated optical signal of a predetermined pattern that varies with time.

14. A method comprising:

receiving light waves from a light source;

receiving an electrical control signal requesting a change in reflectance of the received light waves; and

adjusting an effective order of two or more layers of a plurality of layers of a light modulating stack to change the reflectance of the received light waves based on the electrical control signal.

15. The method of claim 14, wherein adjusting the effective order of two or more layers comprises adjusting the relative location of a plurality of particles with respect to a fluid within which the particles are suspended.

16. The method of claim 14, wherein the effective order of the two or more layers is configured to be adjusted more than 100 times per second.

17. The method of claim 14, wherein adjusting the effective order of two or more layers comprises adjusting the effective order of at least one portion of the two or more layers.

18. The method of claim 14, wherein adjusting the effective order of two or more layers comprises adjusting a bias applied to at least one layer of the light modulating stack.