Holographic MEMS operated optical projectors

• US 20080212040A1
• Filed: 03/02/2007
• Published: 09/04/2008
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Aksyuk, Vladimir Anatolyevich
• Granted Patent: US 9,778,477 B2
• Time in Patent Office: Days
• US Class Current: 353/99
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 27/46 Systems using spatial filters
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus
• CPC Class Codes: G03B 33/12 using beam-splitting or beam-combining systems, e.g. dichroic mirrors
• CPC Class Codes: G03H 1/02 Details of features involved during the holographic process; Replication of holograms without interference recording
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/2249 Holobject properties
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0224 Active addressable light modulator, i.e. Spatial Light Modulator [SLM]
• CPC Class Codes: G03H 2001/0816 Iterative algorithms
• CPC Class Codes: G03H 2001/221 Element having optical power, e.g. field lens
• CPC Class Codes: G03H 2001/2218 being perpendicular to optical axis
• CPC Class Codes: G03H 2001/2271 RGB holobject
• CPC Class Codes: G03H 2001/2297 using frame sequential, e.g. for reducing speckle noise
• CPC Class Codes: G03H 2210/20 2D object
• CPC Class Codes: G03H 2225/24 Having movable pixels, e.g. microelectromechanical systems [MEMS]
• CPC Class Codes: G03H 2227/02 Handheld portable device, e.g. holographic camera, mobile holographic display
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3161 : using laser light sources using laser beams scanning the display screen H04N9/3129
• CPC Class Codes: H04N 9/3164 : using multiple light sources

Abstract

A method forms an image with a reconfigurable array of mirrors. The method includes configuring the array by translating some of the mirrors such that distances of the mirrors of the array from a reference plane have a non-uniform spatial distribution. The method includes illuminating the configured array with a coherent light beam such that part of the light beam is reflected off the array and is projected on a planar viewing screen.

Claims

1. An apparatus, comprising:

a light source comprising a plurality of coherent sources, each coherent source being configured to emit light of a different color than the remaining of the coherent sources;

a reconfigurable array of mirrors and MEMS actuators, each mirror being controlled by a corresponding one of the MEMS actuators that is able to translate the controlled mirror; and

wherein the light source is configured to illuminate the mirrors with a time division color-multiplexed light beam.

2. The apparatus of claim 1, wherein the light source is configured to vary the light beam between having a first color and having a second color at a frequency of greater than 20 Hertz.

3. The apparatus of claim 2, comprising a processor being configured to operate the MEMS actuators such that the mirrors of the array have a first spatial distribution of translations when the light beam has the first color and have a different second spatial distribution of translations when the light beam has the second color.

4. The apparatus of claim 1, further comprising:

a planar viewing screen; and

wherein the apparatus is configured to form an image on a viewing screen such that a human would observe the image to be temporally constant and have a superposition of the colors of the coherent sources.

5. The apparatus of claim 4, wherein the viewing screen non-specularly reflects light incident thereon.

6. The apparatus of claim 1, further comprising:

a beam splitter located to redirect a light beam from the light source towards the reconfigurable array; and

a wave plate located between the beam splitter and the reconfigurable array.

7. The apparatus of claim 1,

wherein the diameters of the mirrors are less than 20 times a center wavelength of light produced by the light source;

and

wherein the processor is configured to operate the MEMS actuators such that the array forms a first image of a first color on a viewing screen and forms a second image of a second color on the viewing screen such that the first and second images have the same size.

8. A method of forming an image with a reconfigurable array of mirrors, comprising:

configuring the array by translating some of the mirrors such that distances of the mirrors of the array from the reference plane have a non-uniform spatial distribution;

illuminating the configured array with a coherent light beam such that part of the light beam is reflected off the array and is projected on a planar viewing screen.

9. The method of claim 8, wherein the illuminating causes the viewing screen to non-specularly reflect part of the light projected thereon.

10. The method of claim 8, further comprising:

then, reconfiguring the array by translating some of the mirrors such that distances of the mirrors of the array from th the reference plane have a new non-uniform spatial distribution;

re-illuminating the reconfigured array with a coherent light beam of a different color such part of the light beam of the different color is projected on the planar viewing screen.

11. The method of claim 10, further comprising:

during each of a series consecutive of time periods, repeating the acts of configuring, illuminating, reconfiguring, and re-illuminating.

12. The method of claim 11, wherein each of the periods is less than 1/20 seconds long.

13. The method of claim 12, wherein the mirrors have largest diameters that are smaller than 20 times a wavelength of light of the light beam.

14. The method of claim 9, wherein the mirrors have largest diameters that are smaller than 20 times the a wavelength of light of the light beam.