Visible spectrum modulator arrays

• US 5,986,796 A
• Filed: 11/05/1996
• Issued: 11/16/1999
• Est. Priority Date: 03/17/1993
• Status: Expired due to Term

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Etalon, Inc.
• Inventors: Miles, Mark W.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Burke, Margaret
• Application Number:
  US08/744,253
• Time in Patent Office: 1,106 Days
• Field of Search: 359/247, 359/254, 359/259, 359/260, 359/263
• US Class Current: 359/260
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• 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
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The amplitude of light delivered by each of the modulation elements is controlled independently by pulse code modulation. Each modulation element has a deformable portion held under tensile stress, and the control circuitry controls the deformation of the deformable portion. Each deformable element has a deformation mechanism and an optical portion, the deformation mechanism and the optical portion independently imparting to the element respectively a controlled deformation characteristic and a controlled modulation characteristic. The deformable modulation element may be a non-metal. The elements are made by forming a sandwich of two layers and a sacrificial layer between them, the sacrificial layer having a thickness related to the final cavity dimension, and using chemical (e.g., water) or a plasma based etch process to remove the sacrificial layer.

Claims

1. A device for modulating light in the visible spectrum, comprising

an array of interferometric modulation elements formed integrally on a substrate

control circuitry connected to the array for controlling each of the modulation elements independently

each of said modulation elements having two walls that define a cavity, one of the walls being movable relative to the other to define response modes, the cavity operating interferometrically on light within the cavity in at least one of the modes, at least one of the walls serving as a mirror and having at least two layers that cooperate to cause the element to exhibit, in modes in which the cavity is operating interferometrically, a predetermined optical response to light, each of the layers contributing substantially to causing the element to exhibit the predetermined optical response,

wherein an optical response of the device in one of the response modes comprises broadband responses for transmission and reflection that respectively span the entire visible range of wavelengths.

2. The device of claim 1 wherein the broadband response for transmission comprises a response of a broadband transmitter across the entire visible range.

3. The device of claim 1 wherein the broadband response for reflection comprises a response of a broadband mirror across the entire visible range.

4. The device of claim 1 wherein the broadband response for transmission comprises a series of peaks across the entire visible range.

5. The device of claim 1 wherein the broadband response for reflection comprises a series of peaks across the entire visible range.

6. The device of claim 1 wherein the optical response in one of the response modes comprises responses for at least one of transmission and reflection that operate on approximately one-third of the visible range.

7. The device of claim 6 wherein the response for transmission or reflection comprises a peak.

8. The device of claim 1 wherein the optical response in one of the response modes comprises responses for at least one of transmission and reflection that operate on approximately two-thirds of the visible range.

9. The device of claim 1 wherein the broadband response for one of transmission or reflection comprises a response of a broadband transmitter or mirror and the broadband response for the other of transmission or reflection does not comprise a response of a broadband transmitter or mirror.

10. The device of claim 6 wherein the response for one of transmission or reflection comprises a response of a broadband transmitter or mirror and the broadband response for the other of transmission or reflection comprises a peak.

11. The device of claim 6 wherein the responses for transmission and reflection have non-matching peaks.

12. The device of claim 6 wherein the responses for transmission and reflection have complementary peaks.

13. The device of claim 1 wherein the optical response of the device in one of the response modes comprises complementary transmission peaks and reflective peaks and in a second one of the response modes comprises complementary transmission peaks and reflection peaks.

14. The device of claim 1 wherein the optical response of the device in one of the response modes comprises a complementary transmission peak and reflective peak and in a second one of the response modes comprises transmission and reflection responses of a broadband transmitter or a broadband mirror.

15. The device of claim 1 wherein the optical response of the device in one of the response modes comprises a reflective peak and essentially no transmission and in a second one of the response modes comprises a different reflective peak and essentially no transmission.

16. The device of claim 1 wherein the optical response of the device in one of the response modes comprises a reflective peak and no transmission peak and in a second one of the response modes there is essentially no transmission and no reflection.

17. The device of claim 1 wherein at least one of the broadband responses comprises multiple narrow band peaks.

18. The device of claim 1 wherein light in the visible spectrum includes ultraviolet light in the visible spectrum.

19. The device of claim 1 wherein light in the visible spectrum includes infrared light in the visible spectrum.