Method and device for providing illumination to interferometric modulators

• US 8,054,532 B2
• Filed: 06/14/2010
• Issued: 11/08/2011
• Est. Priority Date: 05/05/1994
• 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
• Assistant Examiner(s): Patel; Vipin
• Application Number:
  US12/815,136
• Publication Number:
  US 20100309540A1
• Time in Patent Office: 512 Days
• Field of Search: 359/290, 359/291, 359/223, 359/224, 359/238, 359/248
• US Class Current: 359/291
• 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 2006/12104 Mirror; Reflectors or the like
• 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 26/0833 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: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/169 based on orientable non-spherical particles having a common optical characteristic, e.g. suspended particles of reflective metal flakes
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• 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 2300/0452 : Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• 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 3/3466 : 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
• CPC Class Codes: H01Q 9/26 : with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope.

Claims

1. A spatial light modulator comprising:

a light-modulating array including a plurality of light-modulating elements each including an optical cavity defined by first and second reflective surfaces that produce optical interference, said first and second reflective surfaces moveable with respect to each other to alter said optical cavity and enable modulation of said optical interference, said plurality of light-modulating elements having a front side for viewing light modulated by said light-modulating array; and

at least one reflecting element disposed so as to reflect light propagating from a rear side of the plurality of light-modulating elements into at least one of said optical cavities for modulation,

wherein said at least one reflecting element is disposed over the front side of said plurality of light-modulating elements.

2. The spatial light modulator of claim 1, wherein said at least one reflecting element and said plurality of light-modulating elements are disposed over opposite sides of a substrate.

3. The spatial light modulator of claim 1, wherein the at least one reflecting element includes a mirror.

4. The spatial light modulator of claim 1, further comprising a light source disposed rearward of the light modulating array.

5. The spatial light modulator of claim 4,

wherein the plurality of light modulating elements are spaced apart by gaps, and

wherein light from the light source is transmitted forward through the gaps towards a plurality of said reflecting elements.

6. The spatial light modulator of claim 5, wherein the reflective elements in said plurality of reflecting elements are disposed over the gaps thereby aligning the reflecting elements with the gaps.

7. A display including the spatial light modulator of claim 1, wherein the display includes a processor configured to communicate with the spatial light modulator and configured to process image data.

8. The display of claim 7 further including a driver circuit configured to send at least one signal to the spatial light modulator.

9. The display of claim 8 further including a controller configured to send at least a portion of the image data to the driver circuit.

10. A spatial light modulator comprising:

a plurality of means for interferometrically modulating light, each interferometric light-modulating means including means for producing optical interference, the plurality of interferometric light-modulating means having a front side for viewing light modulated by the plurality of interferometric light-modulating means;

at least one means for reflecting light disposed so as to reflect light propagating from a rear side of the plurality of interferometric light-modulating means into at least one of the optical interference-producing means;

wherein the at least one reflecting means is disposed over the front side of the plurality of interferometric light-modulating means.

11. The spatial light modulator of claim 10, wherein the interferometric light-modulating means includes a light-modulating element, and the optical interference-producing means includes an optical cavity defined by first and second reflective surfaces that produce optical interference, the first and second reflective surfaces moveable with respect to each other to alter the optical cavity and enable modulation of the optical interference.

12. The spatial light modulator of claim 10, wherein the at least one reflecting means and the light-modulating means are disposed over opposite sides of a substrate.

13. The spatial light modulator of claim 10, wherein the at least one reflecting means includes a mirror.

14. The spatial light modulator of claim 10, further comprising a means for emitting light disposed rearward of the plurality of interferometric light-modulating means.

15. The spatial light modulator of claim 14,

wherein the plurality of interferometric light-modulating means are spaced apart by at least one means for passing light, and

wherein light from the light-emitting means is transmitted forward through the at least one light-passing means toward the at least one reflecting means.

16. The spatial light modulator of claim 15, wherein the at least one reflecting means is disposed over the at least one light-passing means, thereby aligning the reflecting means with the light-passing means.

17. A method of manufacturing a spatial light modulator, the method comprising:

disposing a plurality of light-modulating elements over a substrate so as to form a light-modulating array, the light-modulating elements each including an optical cavity defined by first and second reflective surfaces that produce optical interference, the first and second reflective surfaces movable with respect to each other to alter the optical cavity and enable modulation of the optical interference, the plurality of light-modulating elements having a front side for viewing light modulated by the light-modulating array; and

disposing at least one reflective element over the front side of the plurality of light-modulating elements so as to reflect light propagating from a rear side of the plurality of light-modulating elements into at least one of the optical cavities for modulation.

18. The method of claim 17, wherein disposing the at least one reflecting element includes forming a mirror.

19. The method of claim 17, further comprising disposing a light source rearward of the light-modulating array.

20. The method of claim 19, wherein disposing the plurality of light-modulating elements includes spacing the light-modulating elements by gaps.

21. The method of claim 20, wherein disposing the at least one reflective element includes aligning the at least one reflective element with at least one gap.