Micro-display engine
View Patent ↗Virtual displays with micro-display engines are arranged in compact, lightweight configurations that generate clear virtual images for an observer. The displays are particularly suitable for portable devices, such as head-mounted displays adapted to non-immersive or immersive applications. The non-immersive applications feature reflective optics moved out of the direct line of sight of the observer and provide for differentially modifying the amount or form of ambient light admitted from the forward environment with respect to image light magnified within the display. Micro-display engines suitable for both non-immersive and immersive display applications and having LCD image sources displace polarization components of the LCD image sources along the optical paths of the engines for simplifying engine design. A compound imaging system for micro-display engines features the use of reflectors in sequence to expand upon the imaging possibilities of the new micro-display engines. Polarization management also provides for differentially regulating the transmission of ambient light with respect to image light and for participating in the image formation function of the image source.
1. A non-immersive virtual image display for combining image light and ambient light comprising:
a housing;
a backlit image source and a reflective focusing optic supported by the housing and aligned along a common optical axis;
a viewing aperture and an ambient-light-admitting aperture formed in the housing and aligned along a viewing axis that is inclined to the common optical axis;
a beamsplitter supported by the housing at an intersection of the common optical axis and the viewing axis;
the beamsplitter being positioned for:
(a) transmitting image light between the backlit image source and the reflective focusing optic along the common optical axis,
(b) reflecting the transmitted image light between the reflective focusing optic and the viewing aperture along the viewing axis, and
(c) transmitting ambient light between the ambient-light-admitting aperture and the viewing aperture along the viewing axis superimposed upon the transmitted image light that is reflected along the viewing axis,
wherein the beamsplitter is polarization sensitive and further comprising a phase adjuster for rotating polarization of the image light transmitted through the polarization-sensitive beamsplitter en route to and from the reflective focusing optic.
2. The display of claim 1 further comprising an optically active component located between the ambient-light-admitting aperture and the beamsplitter for altering the ambient light that is combined with the transmitted image light along the viewing axis.
3. The display of claim 2 in which the optically active component is an optical filter.
4. The display of claim 2 in which the optically active component is a lens.
5. The display of claim 2 in which the optically active component is a polarizer.
6. A non-immersive virtual display for combining image light and ambient light comprising:
a housing having an ambient-light-admitting aperture and a viewing aperture;
a backlit image source;
a reflector;
the housing enclosing optical transmissions of (a) image light from the image source to the reflector along a first optical pathway and (b) ambient light from the ambient-light-admitting aperture to the viewing aperture along a second optical pathway;
a beamsplitter located at an intersection of the first and second optical pathways supporting the transmissions of (a) image light from the backlit image source to the reflector along the first optical pathway and (b) ambient light from the ambient-light-admitting aperture to the viewing aperture along a second optical pathway; and
the beamsplitter also supporting reflection of the transmitted image light from the reflector to the viewing aperture for combining the transmitted image light with the transmitted ambient light along the second optical pathway.
wherein the beamsplitter is polarization sensitive and further comprising a phase adjuster for rotating polarization of the transmitted image light en route to and from the reflector.
7. The display of claim 6 further comprising an optically active component located between the ambient-light-admitting aperture and the beamsplitter for altering the ambient light that is combined with the transmitted image light along the viewing axis.
8. The display of claim 7 in which the optically active component is an optical filter.
9. The display of claim 7 in which the optically active component is a lens.
10. The display of claim 7 in which the optically active component is a polarizer.