Wearable heads up displays
An optical display, including a first waveguide having a first set of surfaces, an input grating, a fold grating, and an output grating; an image input image node assembly; and a prismatic relay optics is provided. The prismatic relay optics may be configured to be optomechanically connected to the waveguide and the input image node assembly. The optical display is may also be configured to operate alone or as integrated with a headpiece to be used as a HUD. The HUD may have a first and a second configuration wherein the waveguide is decoupled or coupled.
1. An optical display comprising:
an input image node (IIN) providing image light of a first wavelength over an angular range;
a curved transparent substrate;
a first waveguide comprising:
at least one input grating configured to couple the image light from said IIN into a total internal reflection (TIR) path in said first waveguide, and
at least one grating for providing beam expansion in at least one direction and transmitting image light from said TIR path in said first waveguide towards the curved transparent substrate; and
a wavefront distortion compensation element,
wherein image light enters a viewer's eyebox after reflection off said curved transparent substrate and diffraction out of said first waveguide by said at least one grating, and
wherein said wavefront distortion compensation element is configured to correct the image light reflected off said curved transparent substrate by compensating for wavefront distortion introduced by reflection off said curved transparent substrate.
2. The optical display of claim 1 , wherein said at least one grating for providing beam expansion and transmitting image light from said TIR path in said first waveguide comprises:
at least one fold grating configured to provide pupil expansion in a first direction; and
at least one output grating configured to provide pupil expansion in a second direction different than said first direction and to cause said image light to exit said first waveguide.
3. The optical display of claim 1 , wherein the at least one input grating and/or the at least one grating is switchable between a diffracting state and a non-diffracting state.
4. The optical display of claim 1 , wherein said wavefront distortion compensation element is a diffractive optical element.
5. The optical display of claim 1 , wherein said wavefront distortion compensation element is a refractive optical element.
6. The optical display of claim 1 , wherein said wavefront distortion compensation element is a plastic optical element.
7. The optical display of claim 6 , wherein said first waveguide further comprises at least one birefringence compensation layer for compensating a birefringence characteristic of said plastic optical element.
8. The optical display of claim 1 , wherein said curved transparent substrate is a car windscreen.
9. The optical display of claim 1 , further comprising a second waveguide, wherein:
said at least one input grating of said first waveguide is configured to couple the first wavelength image light; and
said second waveguide comprises:
at least one input grating configured to couple image light of a second wavelength from said IIN into a TIR path in said second waveguide; and
at least one grating for providing beam expansion in at least one direction and extracting the image light of the second waveguide from said second waveguide.
10. The optical display of claim 9 , further comprising a dichroic filter disposed between said at least one input grating of said first waveguide and said at least one input grating of second waveguide.
11. The optical display of claim 1 , wherein said first waveguide is curved.
12. The optical display of claim 1 , wherein said IIN comprises a spatial light modulator and a projection lens for projecting image modulated first wavelength light over an angular range.
13. The optical display of claim 1 , wherein said IIN comprises a laser scanner for projecting image modulated first wavelength light over an angular range.
14. The optical display of claim 1 , wherein said at least one input grating multiplexes at least one of color or angle.
15. The optical display of claim 1 , wherein said at least one input grating is a rolled k-vector grating.
16. The optical display of claim 1 , wherein said at least one input grating comprises a grating selected from the group consisting of:
a Bragg grating,
a switchable Bragg grating,
a grating recorded in a liquid crystal and polymer-based material, and
a surface relief grating.
17. The optical display of claim 1 , further comprising at least one of:
an eye tracker,
a dynamic focus lens disposed within said IIN,
a dynamic focus lens disposed in proximity to one of the total internal refection surfaces of the first waveguide,
a beam homogenizer, or
at least one gradient index image transfer waveguide portion.
18. The optical display of claim 1 , wherein said IIN further comprises a spatially varying numerical aperture component for providing a numerical aperture variation along at least one direction.
19. The optical display of claim 18 , wherein said spatially varying numerical aperture component has at least one of diffractive, birefringent, refracting or scattering characteristics.