Method and device for modulating light with semiconductor substrate

• US 7,830,587 B2
• Filed: 08/20/2007
• Issued: 11/09/2010
• Est. Priority Date: 03/17/1993
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Miles, Mark W.
• Primary Examiner(s): Mack; Ricky L
• Assistant Examiner(s): Thomas; Brandi N
• Application Number:
  US11/841,741
• Publication Number:
  US 20080088904A1
• Time in Patent Office: 1,177 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298
• US Class Current: 359/290
• 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: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G06F 3/1446 display composed of modules, e.g. video walls
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/088 using a non-linear two-terminal element
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• 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 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/2077 by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

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 water or an oxygen based plasma to remove the sacrificial layer.

Claims

1. A light modulation device, comprising:

a substrate comprising a semiconductor material;

first and second layers formed on the substrate, the first and second layers having a cavity therebetween, wherein the first layer is at least partially transparent and the second layer is opaque and is configured to move relative to the substrate; and

at least one additional set of first and second layers formed on the substrate, the additional set of first and second layers having an additional cavity therebetween, wherein the additional first layer is at least partially transparent and the additional second layer is opaque and is configured to move relative to the substrate, wherein the device is configured to display an image.

2. The device of claim 1, wherein the semiconductor material comprises silicon.

3. The device of claim 1, wherein the second layer is at least partially reflective.

4. The device of claim 1, wherein the second layer is configured to move in response to a voltage applied across the first and second layers.

5. The device of claim 4, wherein the second layer is configured to move in response to a continuously varying voltage.

6. The device of claim 4, wherein the height of the cavity is reduced in response to the applied voltage.

7. The device of claim 1, wherein at least one of the first and second layers is configured to cause light to reflect depending at least in part on height of the cavity.

8. The device of claim 7, wherein the cavity is configured to modulate color of the reflected light.

9. The device of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

10. The device of claim 9, further comprising a driver circuit configured to send at least a data signal to the display.

11. The device of claim 10, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

12. The device of claim 9, further comprising an image source module configured to send said image data to said processor.

13. The device of claim 12, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

14. The device of claim 9, further comprising an input device configured to receive input data and to communicate said input data to said processor.

15. A light modulation device, comprising:

first and second means for reflecting light, the first and second reflecting means having a cavity therebetween, wherein the first reflecting means is at least partially transparent and the second reflecting means is opaque and is configured to move relative to the first reflecting means;

means for supporting the first and second reflecting means, the supporting means comprising a semiconductor material; and

at least one additional set of first and second means for reflecting, wherein the additional set of first and second reflecting means are formed on the supporting means, and the additional set of first and second reflecting means have a cavity therebetween, and wherein the additional first reflecting means is at least partially transparent and the additional second reflecting means is opaque and is configured to move relative to the supporting means, and the device is configured to display an image.

16. The device of claim 15, wherein the supporting means comprises a substrate.

17. The device of claim 16, wherein the first reflecting means comprises a partially transparent layer.

18. The device of claim 17, wherein the second reflecting means comprises a movable layer.

19. The device of claim 15, wherein the semiconductor material comprises silicon.

20. The device of claim 15, wherein the second reflecting means is configured to move in response to a voltage applied across the first and second reflecting means.