Microelectrical mechanical structure (MEMS) optical modulator and optical display system

• US 7,151,627 B2
• Filed: 06/21/2004
• Issued: 12/19/2006
• Est. Priority Date: 10/31/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sinclair, Michael J, Starkweather, Gary K
• Primary Examiner(s): Dang, Hung Xuan
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US10/872,741
• Publication Number:
  US 20050002086A1
• Time in Patent Office: 911 Days
• Field of Search: 359/290, 359/291, 359/292, 359/223, 359/224, 359/230, 359/288, 359/302, 359/621, 359/622, 359/623
• US Class Current: 359/291
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/353 the optical element being a shutter, baffle, beam dump or opaque element absorbers on light guide termination G02B6/243
• CPC Class Codes: G02B 6/3554 3D constellations, i.e. with switching elements and switched beams located in a volume
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3576 Temperature or heat actuation thermal forces controlling reflecting elements in general G02B26/0866; thermo-optic devices G02F1/0147
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3594 Characterised by additional functional means, e.g. means for variably attenuating or branching or means for switching differently polarized beams
• CPC Class Codes: H04N 5/7408 Direct viewing projectors, e.g. an image displayed on a video CRT or LCD display being projected on a screen
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal

Abstract

A MEMS optical display system includes an illumination source for providing illumination light, a collimating lens for receiving the illumination light and forming from it collimated illumination light, and a converging microlens array having an array of lenslets that converge the collimated illumination light. The converging microlens array directs the illumination light to a microelectrical mechanical system (MEMS) optical modulator. The MEMS optical modulator includes, for example, a planar substrate through which multiple pixel apertures extend and multiple MEMS actuators that support and selectively position MEMS shutters over the apertures. A MEMS actuator and MEMS shutter, together with a corresponding aperture, correspond to pixel. The light from the converging microlens array is focused through the apertures and is selectively modulated according to the positioning of the MEMS shutters by the MEMS actuators, thereby to impart image information on the illumination light. The light is then passed to a diffused transmissive display screen by a projection microlens array.

Claims

1. A microelectrical mechanical multi-pixel optical modulator, comprising:

a planar substrate with plural pixel regions; and

plural microelectrical mechanical actuators that support and selectively position plural microelectrical mechanical shutters to selectively modulate light for illuminating a display directed at the pixel regions;

wherein the actuators are thermal actuators and wherein each actuator comprises a beam adapted to exert a rotational force to position a respective shutter.

2. The optical modulator of claim 1 in which each pixel region includes an aperture that extends through the planar substrate.

3. The optical modulator of claim 1 in which each pixel region includes a reflector on the planar substrate.

4. The optical modulator of claim 1 in which the actuators provide selective positioning of the shutters generally in a plane that is parallel to the substrate.

5. The optical modulator of claim 1 in which the actuators provide selective positioning of the shutters generally in a plane that is transverse to the substrate.

6. A microelectrical mechanical optical display, comprising:

an illumination source that provides illumination light to illuminate a display;

a collimating lens that receives the illumination light and forming from it collimated illumination light;

plural microelectrical mechanical optical modules that each include a converging microlens array having an array of plural lenslets that converge the illumination light, a microelectrical mechanical optical modulator including a planar substrate with plural pixel regions and plural microelectrical mechanical actuators that support and selectively position plural microelectrical mechanical shutters over the pixel regions to selectively modulate the illumination light from the converging microlens array, a projection microlens array having an array of plural lenslets and being positioned to receive modulated light from the optical modulator to project the modulated light, and a mounting structure configured to fit together with other such mounting structures, wherein the plural optical modules are arranged in an array, wherein the actuators are thermal actuators, and wherein each actuator comprises a beam adapted to exert a rotational force to position a respective shutter; and

a display screen that receives the illumination light passing the microelectrical mechanical optical modulator.

7. The optical display of claim 6 in which the illumination source provides illumination light for all of the optical modules.

8. The optical display of claim 6 in which each pixel region includes an aperture that extends through the planar substrate.

9. The optical display of claim 6 in which the actuators provide selective positioning of the shutters generally in a plane that is parallel to the substrate.

10. The optical display of claim 6 in which the actuators provide selective positioning of the shutters generally in a plane that is transverse to the substrate.

11. A microelectrical mechanical optical module, comprising:

converging microlens array means for converging illumination light;

microelectrical mechanical optical modulator means for selectively modulating light for illuminating a display from the converging microlens array including a planar substrate with plural pixel regions and plural microelectrical mechanical thermal buckle-beam actuators that support and selectively position plural microelectrical mechanical shutters over the pixel regions, wherein each actuator comprises a beam adapted to exert a rotational force to position a respective shutter; and

projection microlens array means positioned to receive modulated light from the optical modulator for projecting the modulated light.

12. The optical module of claim 11 in which the converging microlens array means includes an array of plural lenslets.

13. The optical module of claim 11 in which the projection microlens array means includes an array of plural lenslets.