Holographic Waveguide Display

• US 20150160529A1
• Filed: 12/11/2013
• Published: 06/11/2015
• Est. Priority Date: 12/11/2013
• Status: Active Grant

• Current Assignee: DigiLens Inc, Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: SBG Labs Inc.
• Inventors: Popovich, Milan Momcilo, Waldern, Jonathan David
• Granted Patent: US 9,335,604 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/0107 with optical power
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 5/1828 having means for producing variable diffraction controlling the direction of light by means of one or more diffracting elements G02B26/0808; acousto-optical elements G02F1/11, G02F1/33; electro- or magneto-optical diffraction G02F1/292, G02F1/2955
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02F 1/13342 Holographic polymer dispersed liquid crystals
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G03B 13/02 Viewfinders
• CPC Class Codes: G03B 21/10 Projectors with built-in or built-on screen
• CPC Class Codes: G03H 2001/2226 Edge lit holograms TIR recording G03H1/0408

Abstract

A holographic waveguide display comprises: a source of light; at least one switchable grating layer comprising a multiplicity of grating regions each switchable between a diffracting state and a non diffracting state; means for spatio-temporally modulating light from the source to provide image light comprising at least one beam deflector for scanning the light in at least one of two orthogonal directions and at least one modulator for amplitude modulating the light. A first scanned angular range of light is diffracted through a first area into a first field of view by a first set of grating regions, and through a second area into to the first field of view by a second set of grating regions. Each grating region of the first and second sets has a first grating function. The first and second areas lie within an exit pupil of the display.

Claims

1. An apparatus for producing an image comprising:

a source of light of a first wavelength;

at least one SBG layer comprising a multiplicity of grating regions each switchable between a diffracting state and a non diffracting state;

first and second transparent plates sandwiching said at least one SBG layer, said transparent plates together functioning as a light guide;

a multiplicity of independently switchable transparent electrode elements applied to said plates overlaying said switchable grating regions;

means for spatio-temporally modulating light from said source to provide image light comprising at least one beam deflector for scanning said light in at least one of two orthogonal directions and at least one modulator for amplitude modulating said light; and

means for coupling said image light into said light guide,

wherein a first scanned angular range of light coupled into said light guide is diffracted out of said light guide through a first area into a first field of view by a first set of grating regions in said diffracting state, and through a second area into to said first field of view by a second set of grating regions in said diffracting state each grating region of said first and second sets having a first grating function.

2. The apparatus of claim 1, wherein said first and second areas abut.

3. The apparatus of claim 1 wherein said first and second areas lie within the exit pupil of said apparatus.

4. The apparatus of claim 1, wherein said first and second set of grating regions each comprise a rectangular matrix of elements.

5. The apparatus of claim 1, wherein said first and second set of grating regions comprises at least one row or column of a rectangular matrix of elements, each said row or column being switched into said diffracting state sequentially.

6. The apparatus of claim 1, wherein said means for spatio-temporally modulating light and said modulator are disposed between said source and said light guide.

7. The apparatus of claim 1, wherein said source provides first, second and third wavelength light and each said grating region diffracts said first, second and third wavelength light incident at first, second and third angles into a common output direction.

8. The apparatus of claim 1, wherein said source of light provides collimated light.

9. The apparatus of claim 1, further comprising a despeckler.

10. The apparatus of claim 1, wherein said at least one SBG layer forms an image located outside said light guide.

11. The apparatus of claim 1, wherein at least one of said plates has at least one of a reflective or transmissive diffractive surface and said diffractive surface in combination with said at least one SBG layer forms an image located outside said light guide.

12. The apparatus of claim 1, wherein said grating regions encode images of symbols.

13. The apparatus of claim 1, wherein said plates and said at least one SBG layer are curved.

14. The apparatus of claim 1, further comprising at least one of a beam expander disposed between said source and said lightguide and a scan angle magnifying optical system disposed between said source and said lightguide.

15. The apparatus of claim 1, wherein first and second modulators and first and second beam deflectors are provided, wherein light modulated by said first modulator and first beam deflector is injected into said light guide into via a first edge of said light guide into a first propagation direction in said lightguide, wherein light modulated by said second modulator and second beam deflector is injected into said light guide via a second edge of said light guide into a second propagation direction in said lightguide, wherein said first and second edges are orthogonal and said first and second propagation directions are orthogonal.

16. The apparatus of claim 1, wherein said beam deflector comprises a rotatable mirror and a electro mechanical drive.

17. The apparatus of claim 1, wherein said means for coupling said light into said light guide is one of a grating or a prism.

18. The apparatus of claim 1, wherein said apparatus provides one of a wearable display, a head up display, a viewfinder, or a projection display.

19. The apparatus of claim 1, wherein said grating regions are one of transmission or reflection gratings.

20. The apparatus of claim 1, wherein said grating regions perform at least one of the functions of applying spatial modulation to said light, applying temporal modulation to said light, modifying the wavefront shape of said light and modifying the spatial amplitude of said light.