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

• US 6,775,048 B1
• Filed: 10/31/2000
• Issued: 08/10/2004
• 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): Epps, Georgia
• Assistant Examiner(s): Tra, Tuyen
• Application Number:
  US09/702,585
• Time in Patent Office: 1,379 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, 359/295, 359/572, 359/558, 359/556
• 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 optical display system, comprising:

an illumination source that provides illumination light;

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

a converging microlens array having an array of plural lenslets that converge the collimated illumination light;

a microelectrical mechanical optical modulator including a planar substrate through which plural pixel apertures extend and plural pivoting microelectrical mechanical actuators that support and selectively pivot plural microelectrical mechanical shutters over the apertures in directions parallel to the planar substrate, the microelectrical mechanical optical modulator being positioned such that the pixel apertures receive the illumination light from the converging microlens array, the illumination light passing through the microelectrical mechanical optical modulator selectively according to the selective pivoting of the shutters; and

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

2. A microelectrical mechanical optical display system, comprising:

an illumination source that provides illumination light;

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

a converging microlens array having an array of plural lenslets that converge the collimated illumination light;

a microelectrical mechanical optical modulator including a planar substrate through which plural pixel apertures extend and plural microelectrical mechanical thermal actuators that support and selectively pivot plural microelectrical mechanical shutters over the apertures in directions parallel to the planar substrate, the microelectrical mechanical optical modulator being positioned such that the pixel apertures receive the illumination light from the converging microlens array, the illumination light passing the microelectrical mechanical optical modulator selectively according to the selective positioning of the shutters;

a display screen that receives the illumination light passing through the microelectrical mechanical optical modulator; and

a projection microlens array positioned between the microelectrical mechanical optical modulator and the display screen and having an array of plural lenslets that project the illumination light to the display screen.

3. The display system of claim 2 in which the illumination source includes only one light source.

4. The display system of claim 2 in which the illumination source includes plural light sources of different colors.

5. The display system of claim 4 further comprising a field sequential controller that operates the plural light sources alternately and controlling the shutters in coordination with the light sources in a field sequential manner.

6. The display system of claim 2 in which the display screen is a transmissive display screen.

7. The display system of claim 2 further comprising housing that contains the display system to form a display module that can fit together with or engage other such display modules.

8. The display system of claim 2 in which the illumination source is monochromatic.

9. The display system of claim 2 in which the illumination source is polychromatic.

10. A microelectrical mechanical optical display system, comprising:

an illumination source that provides illumination light;

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

a converging microlens array having an array of plural lenslets that converge the collimated illumination light;

a microelectrical mechanical optical modulator including a planar substrate through which plural pixel apertures extend and plural microelectrical mechanical actuators that support respective plural microelectrical mechanical shutters over the apertures with distinct, non-overlapping pairs of arms, the plural microelectrical mechanical actuators selectively positioning the respective plural microelectrical mechanical shutters in directions parallel to the planar substrate, the microelectrical mechanical optical modulator being positioned such that the pixel apertures receive the illumination light from the converging microlens array, the illumination light passing the microelectrical mechanical optical modulator selectively according to the selective positioning of the shutters, and the microelectrical mechanical actuators of the microelectrical mechanical optical modulator being thermal microelectrical mechanical actuators; and

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

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

a planar substrate with opposed planar surfaces and plural pixel regions that each includes an aperture that extends completely through the planar substrate; and

plural microelectrical mechanical actuators that are positioned on one of the planar surfaces and that support and selectively pivot plural microelectrical mechanical shutters in directions parallel to the planar substrate to selectively modulate light directed at the pixel regions.

12. The optical modulator of claim 11 in which the actuators provide selective pivoting of the shutters generally out of a plane that is parallel to the substrate.

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

a planar substrate with plural pixel regions; and

plural microelectrical mechanical thermal actuators that have distinct, non-overlapping pairs of arms and support and selectively position plural microelectrical mechanical shutters in directions parallel to the planar substrate to selectively modulate light directed at the pixel regions, the actuators providing selective positioning of the shutters generally in a plane that is transverse to the substrate.

14. A microelectrical mechanical optical module, comprising:

a converging microlens array having an array of plural lenslets that converge 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 in directions parallel to the planar substrate to selectively occlude light from the converging microlens array,

a diffused display screen that receives the illumination light passing through the microelectrical mechanical optical modulator;

a projection microlens array having an array of plural lenslets and being positioned between the microelectrical mechanical optical modulator and the diffused display screen to receive non-occluded light from the optical modulator to project the non-occluded light to the diffused display screen; and

a mounting structure that encompasses the converging microlens array, the microelectrical mechanical optical modulator means, and the projection microlens array and allows the module to fit together with other such modules.

15. The optical module of claim 14 further comprising a mounting structure that contains or encompasses the converging microlens array, the microelectrical mechanical optical modulator, and the projection microlens array, the mounting structure being configured to fit together with other such mounting structures.

16. The optical module of claim 14 in which each pixel region includes an aperture that extends through the planar substrate.

17. The optical module of claim 14 in which the actuators provide selective positioning of the shutters generally in a plane that is parallel to the substrate.

18. A microelectrical mechanical optical module, comprising:

a converging microlens array having an array of plural lenslets that converge illumination light;

a microelectrical mechanical optical modulator including a planar substrate with plural pixel regions and plural microelectrical mechanical thermal actuators having a pair of distinct arms that support and selectively position plural microelectrical mechanical shutters over the pixel regions to selectively modulate 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 that encompasses the converging microlens array, the microelectrical mechanical optical modulator means, and the projection microlens array and allows the module to fit together with other such modules.

19. A microelectrical mechanical optical module, comprising:

a converging microlens array having an array of plural lenslets that converge illumination light;

a microelectrical mechanical optical modulator including a planar substrate with plural pixel regions and plural microelectrical mechanical actuators having a pair of distinct, non-overlapping arms that support and selectively pivot plural microelectrical mechanical shutters over the pixel regions to selectively modulate light from the converging microlens array; and

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, the actuators providing selective positioning of the shutters generally in a plane that is transverse to the substrate.

20. A microelectrical mechanical optical display, comprising:

an illumination source that provides illumination light;

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 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 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; and

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

wherein the actuators provide selective positioning of the shutters generally in a plane that is parallel to the substrate.