NEAR-TO-EYE DISPLAY DEVICE

• US 20170299869A1
• Filed: 06/23/2017
• Published: 10/19/2017
• Est. Priority Date: 12/26/2014
• Status: Active Grant

• Current Assignee: CY Vision, Inc.
• Original Assignee: CY Vision, Inc.
• Inventors: Urey, Hakan, Ulusoy, Erdem
• Granted Patent: US 10,571,696 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 3/032 Devices for presenting test symbols or characters, e.g. test chart projectors A61B3/036 takes precedence
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G03H 1/2202 Reconstruction geometries or arrangements
• CPC Class Codes: G03H 1/2205 using downstream optical component
• CPC Class Codes: G03H 1/2286 Particular reconstruction light G03H1/24 takes precedence; Beam properties
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/2207 Spatial filter, e.g. for suppressing higher diffraction orders
• CPC Class Codes: G03H 2001/2231 Reflection reconstruction
• CPC Class Codes: G03H 2001/2234 Transmission reconstruction
• CPC Class Codes: G03H 2001/2242 : Multiple viewing windows
• CPC Class Codes: G03H 2210/30 : 3D object
• CPC Class Codes: G03H 2222/34 : Multiple light sources
• CPC Class Codes: G03H 2225/60 : Multiple SLMs
• CPC Class Codes: G03H 2227/02 : Handheld portable device, e.g. holographic camera, mobile holographic display
• CPC Class Codes: G03H 2240/61 : SLM related parameters, e.g. pixel size
• CPC Class Codes: G06T 11/00 : 2D [Two Dimensional] image generation
• CPC Class Codes: G06T 11/60 : Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 15/00 : 3D [Three Dimensional] image rendering
• CPC Class Codes: G06T 19/006 : Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00
• CPC Class Codes: G09G 3/02 : by tracing or scanning a light beam on a screen
• CPC Class Codes: G09G 3/3466 : based on interferometric effect

Abstract

A near-to-eye display device includes a spatial light modulator. The spatial light modulator modulates an illumination wave to create a virtual-scene wave that is steered to a useful portion of an exit pupil plane. Higher diffraction orders and noise beams are filtered out by the user'"'"'s pupil acting as a spatial filter.

Claims

1. A head-worn display device comprising:

a computer unit;

at least one point light source mounted on the head-worn display device; and

at least one spatial light modulator (SLM) mounted on the head-worn display device and operatively coupled to the computer unit;

wherein light produced by the at least one point light source illuminates the SLM and gets modulated to produce modulated light, and the modulated light is directed on an exit pupil plane that includes a useful portion,

wherein a light wave distribution within the useful portion is equal to a computed light distribution from a virtual scene,

wherein the useful portion is steerable across the exit pupil plane to follow a motion of a user'"'"'s eye pupil relative to user'"'"'s eye when the head-worn display device is in use so that the user'"'"'s eye pupil acts as a spatial filter, and

wherein the computer unit adds a controlled phase variation to the computed light distribution of the virtual scene such that speckle is reduced.

2. The head-worn display device of claim 1, wherein the spatial light modulator modulates only a phase of the light illuminating the SLM.

4. The head-worn display device of claim 1, wherein the spatial light modulator modulates a phase and an amplitude of the light illuminating the SLM.

5. The head-worn display device of claim 1, wherein the spatial light modulator is reflective.

6. The head-worn display device of claim 1, wherein the spatial light modulator is transmissive.

7. The head-worn display device of claim 1, wherein a width of the useful portion is greater than an expected width of a user'"'"'s eye pupil.

8. The head-worn display device of claim 1, wherein a width of the useful portion is greater than 3 mm.

9. The head-worn display device of claim 1, wherein the light projected on the exit pupil plane includes multiple image copies, and the useful portion includes only one image copy.

10. The head-worn display device of claim 1, wherein the SLM produces higher diffraction orders that fall outside the useful portion, and wherein the user'"'"'s eye pupil acts to filter out the higher diffraction orders.

11. The head-worn display device of claim 1, wherein the SLM produces quantization noise that falls outside the useful portion, and wherein the user'"'"'s eye pupil acts to filter out the quantization noise.

12. The head-worn display device of claim 1, wherein the SLM produces conjugate beams that fall outside the useful portion, and wherein the user'"'"'s eye pupil acts to filter out the conjugate beams.

13. The head-worn display device of claim 1, wherein the SLM produces a DC beam that falls outside the useful portion, and wherein the user'"'"'s eye pupil acts to filter out the DC beam.

14. The head-worn display device of claim 1, wherein the virtual scene is two dimensional.

15. The near-to-eye head-worn display device of claim 1, wherein the virtual scene is three dimensional.

21. The head-worn display device of claim 1, wherein the controlled phase variation includes a phase delay variation such that individual waves from the virtual scene points arrive to the useful portion in-phase to reduce speckle.

22. The head-worn display device of claim 1, wherein the controlled phase variation includes a phase delay variation to produce a smoothly interpolated version of a plurality of points on a user'"'"'s retina to reduce speckle.

23. The head-worn display device of claim 1, further comprising:

a lens located in an optical path between the spatial light modulator and the user'"'"'s eye.

24. The head-worn display device of claim 1, further comprising:

a beam splitter located in an optical path between the spatial light modulator and the user'"'"'s eye.

3. (canceled)

16. A method comprising:

determining a two-dimensional complex-valued profile of a virtual scene wave on a useful portion of an exit pupil plane;

computing a back propagation of the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane to a spatial light modulator plane to determine an ideal two-dimensional complex-valued wave profile at an exit of the spatial light modulator;

determining a two-dimensional complex-valued profile of an illumination wave that will illuminate the spatial light modulator;

assigning one of a plurality of controlled phase values to each of the plurality of virtual scene points to reduce speckle;

extracting the two-dimensional complex-valued wave profile of the illumination wave from the ideal two-dimensional complex-valued wave profile at the exit of the spatial light modulator to obtain a two-dimensional ideal analog complex-valued spatial light modulator transmittance;

applying prefiltering and sampling to the two-dimensional ideal analog complex-valued spatial light modulator transmittance to obtain a two-dimensional ideal complex-valued discrete spatial light modulator image; and

encoding the two-dimensional ideal complex valued discrete spatial light modulator image into a two-dimensional actual digital spatial light modulator image that is suitable for displaying by the spatial light modulator, where noise introduced by the spatial light modulator is distributed to regions outside the useful portion.

17. The method of claim 16, wherein the determining of the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane comprises using a point cloud object model to represent a virtual scene as a plurality of point light sources and superposing waves emitted by the plurality of point light sources.

19. The method of claim 16, wherein the determining of the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane comprises:

partitioning the virtual scene into a plurality of spherical surfaces concentric at a center of the useful portion of the exit pupil plane with different radii;

forming a matrix for each of the spherical surfaces where each element of the matrix is associated with a specific angular location on the sphere, and each element is filled with the complex amplitude of the point source at that angular location on the sphere;

inverse Fourier transforming the matrix to create a result;

multiplying the result by a common diverging lens term with a focal length equal to the radius of the sphere; and

repeating the partitioning, forming, inverse Fourier transforming, and multiplying for each of the plurality of spherical surfaces and superposing to find the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane.

20. The method of claim 16, wherein:

waves from a first plurality of subsections of the displayed virtual scene are reconstructed over the entire useful portion so that each of the first plurality of subsections appears focused on the retina only when the user accommodates to the depth of that subsection; and

waves from a second subsection of the displayed virtual scene are reconstructed over smaller regions of the useful portion so that these parts always appear focused on the retina.

25. The method of claim 16,

wherein the computing of the back-propagation of the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane to a spatial light modulator plane to determine the ideal two-dimensional complex-valued wave profile at the exit of the spatial light modulator takes into account aberrations of optical components in between the exit pupil plane and a source of the illumination wave, and

wherein the determining of the two-dimensional complex-valued profile of the illumination wave that will illuminate the spatial light modulator.

18. (canceled)

26. An apparatus comprising:

a head-worn display device;

means for determining a two-dimensional complex-valued profile of a virtual scene wave on a useful portion of an exit pupil plane;

means for back-propagating the two-dimensional complex-valued profile of the virtual scene wave on the useful portion of the exit pupil plane to a spatial light modulator plane to determine an ideal two-dimensional complex-valued wave profile at an exit of the spatial light modulator free of paraxial or small-angle approximations whereby aberrations of the optical components in between are taken into account;

means for determining a two-dimensional complex-valued profile of an illumination wave that will illuminate the spatial light modulator with aberrations of the optical components in between taken into account;

means for assigning controlled phase values to each of the plurality of virtual scene points to reduce speckle;

means for extracting the two-dimensional complex-valued wave profile of the illumination wave from the ideal two-dimensional complex-valued wave profile at the exit of the spatial light modulator to obtain a two-dimensional ideal analog complex-valued spatial light modulator transmittance;

means for applying prefiltering and sampling to the two-dimensional ideal analog complex-valued spatial light modulator transmittance to obtain a two-dimensional ideal complex-valued discrete spatial light modulator image; and

means for encoding the two-dimensional ideal complex-valued discrete spatial light modulator image into a two-dimensional actual digital spatial light modulator image that is suitable for displaying by the spatial light modulator, where noise introduced by the spatial light modulator is distributed to regions outside the useful portion.