Light modulator with tunable optical state

• US 7,733,553 B2
• Filed: 09/21/2005
• Issued: 06/08/2010
• Est. Priority Date: 09/21/2005
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Yeh, Bao-Sung Bruce, Faase, Kenneth, Nikkel, Eric L., Piehl, Arthur, Jilani, Adel, Przybyla, James R., McKinnell, James C.
• Primary Examiner(s): Mack; Ricky L
• Assistant Examiner(s): PINKNEY, DAWAYNE
• Application Number:
  US11/233,225
• Publication Number:
  US 20070064295A1
• Time in Patent Office: 1,721 Days
• Field of Search: 359/245, 359260-261, 359/263, 359/298, 359301-303, 359/317, 359/318, 359/577
• US Class Current: 359/245
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

An electronic light modulator device for at least partially displaying a pixel of an image, the device comprising first and second reflectors defining an optical cavity therebetween, the optical cavity being selective of an electromagnetic wavelength at an intensity by optical interference, the device having at least first and second optical states, at least one of the optical states being tunable and the other not tunable.

Claims

1. An electronic light modulator device for at least partially displaying a pixel of an image, the device comprising first and second reflectors defining an optical cavity therebetween, the first reflector being partially reflective and being disposed at a fixed position, and the second reflector being disposed between the fixed position of the first reflector and a fixed control electrode, the optical cavity being selective of an electromagnetic wavelength at an intensity by optical interference, the device having at least first and second optical states, the first optical state being continuously tunable by moving the second reflector while the first, partially reflective, reflector remains fixed, and the second optical state not being tunable.

2. The electronic light modulator device of claim 1 formed as a MEMS device.

3. The electronic light modulator device of claim 1 wherein the first and second reflectors form a Fabry-Perot interferometer.

4. An optical interference pixel display comprising a plurality of the electronic light modulator devices of claim 1.

5. The electronic light modulator of claim 1, comprising a Fabry-Perot interferometer, wherein the optical cavity is a variable optical gap, the variable optical gap being continuously controllable from a rest state with no control voltage applied to a first optical state and a second optical state, wherein the optical gap in the rest state is smaller than the optical gap in the first optical state, and the optical gap in the first optical state is smaller than the optical gap in the second optical state.

6. The Fabry-Perot interferometer of claim 5, wherein the first optical state is continuously tunable.

7. The Fabry-Perot interferometer of claim 6, wherein the first optical state is tunable to a black state.

8. The Fabry-Perot interferometer of claim 6, wherein the first optical state is tunable for maximum contrast ratio.

9. An optical interference pixel display comprising a plurality of the Fabry-Perot interferometers of claim 6.

10. The Fabry-Perot interferometer of claim 5, wherein the control voltage is continuously controllable by an analog signal.

11. An optical interference pixel display comprising a plurality of the Fabry-Perot interferometers of claim 10.

12. The Fabry-Perot interferometer of claim 5, wherein the control voltage is controllable by a digital signal.

13. An optical interference pixel display comprising a plurality of the Fabry-Perot interferometers of claim 12.

14. The electronic light modulator of claim 1, comprising a Fabry-Perot interferometer, wherein the control electrode is grounded, and the second reflector is electrically coupled to a signal source.

15. The Fabry-Perot interferometer of claim 14, wherein the first reflector is held at a fixed electric potential.

16. The Fabry-Perot interferometer of claim 15, wherein the fixed electric potential is above ground.

17. An optical interference pixel display comprising a plurality of the Fabry-Perot interferometers of claim 15.

18. The Fabry-Perot interferometer of claim 1, wherein the control electrode is electrically coupled to a signal source.

19. The Fabry-Perot interferometer of claim 18, wherein the first and second reflectors are electrically coupled.

20. The Fabry-Perot interferometer of claim 18, wherein the first and second reflectors are electrically grounded.

21. An optical interference pixel display comprising a plurality of the Fabry-Perot interferometers of claim 18.

22. An electronic device for displaying a pixel of an image, comprising in combination:

means for interference of electromagnetic radiation including at least two substantially parallel means for reflecting the electromagnetic radiation, one of the at least two substantially parallel means for reflecting being partially reflective and being disposed at a fixed position, and

means for controlling the other of the at least two means for reflecting to form at least two distinct optical states, at least one of the two distinct optical states being continuously tunable by moving the other of the at least two means for reflecting.

23. An optical interference pixel display comprising a plurality of the electronic devices of claim 22.

24. An electronic light modulator device for at least partially displaying a pixel of an image, the device comprising:

a) first and second reflectors defining an optical cavity therebetween, the optical cavity being selective of an electromagnetic wavelength at an intensity by optical interference, and

b) first, second, and third electrodes, the first electrode being coupled to the first reflector, the second electrode being coupled to the second reflector, and the third electrode being coupled to a control plate, whereby a number of optical states are selectable by selectively applying an electric potential between at least two of the first, second, and third electrodes,

wherein the number of selectable optical states include at least a first optical state that is continuously tunable and a second optical state that is not tunable.

25. An electronic Fabry-Perot interferometer light modulator device for at least partially displaying a pixel of an image, the device comprising:

a) substantially parallel first and second reflector plates having first and second reflecting surfaces respectively, the first reflecting surface being partially reflective and the second reflective surface being fully reflective, the second reflecting plate being movable, the first and second reflecting surfaces being spaced apart by a variable optical gap between the first and second reflecting surfaces, defining a variable optical cavity therebetween, the variable optical cavity being selective of an electromagnetic wavelength at an intensity by optical interference, the device having at least first and second optical states, the first optical state being continuously tunable by moving the second reflecting plate, and the second optical state not being tunable; and

b) at least one fixed electrostatic control plate adapted to control the variable optical cavity by application of a control voltage, the control plate being spaced apart from the first reflector plate by a first distance and being spaced apart from the second reflector plate by a second distance smaller than the first distance, whereby the first reflective surface is disposed between the fixed electrostatic control plate and the second reflective surface.