US 9,958,684 B1Granted

Compact display engine with MEMS scanners

AssigneeMicrosoft Technology Licensing, LLC

InventorSteven John Robbins

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Abstract

A near-eye optical display system utilizes a compact display engine that couples image light from an imager to a waveguide-based display having diffractive optical elements (DOEs) that provide exit pupil expansion in two directions. The display engine comprises a pair of single axis MEMS (Micro Electro Mechanical System) scanners that are configured to reflect the image light through horizontal and vertical scan axes of the display system's field of view (FOV) using raster scanning. The MEMS scanners are arranged with their axes of rotation at substantially right angles to each other and operate with respective quarter wave retarder plates and a polarizing beam splitter (PBS) to couple the image light into an in-coupling DOE in the waveguide display without the need for additional optical elements such as lenses or relay systems.

Claims20

Dependent claims

A near-eye optical display system configured to show images within a field of view (FOV) described by a first direction and a second direction, comprising:

a waveguide display comprising one or more diffractive optical elements (DOEs) including an in-coupling DOE configured for in-coupling image light to the waveguide display;
a polarizing beam splitter located proximate to the in-coupling DOE, the polarizing beam splitter configured to reflect image light having a first polarization state and transmit image light having a second polarization state;
a first MEMS (micro electro mechanical system) scanner and configured to scan in the first direction of the FOV;
a first quarter wave plate having an optical axis that is parallel to front and rear faces of the first quarter wave plate, the first MEMS scanner being disposed proximate to the front face and the polarizing beam splitter being disposed proximate to the rear face;
a second MEMS scanner configured to scan in the second direction of the FOV;
and
a second quarter wave plate having an optical axis that is parallel to front and rear faces of the second quarter wave plate, the second MEMS scanner being disposed proximate to the front face and the polarizing beam splitter being disposed proximate to the rear face,
wherein image light from an imager incident on the polarizing beam splitter propagates to each of the first and second MEMS scanners in succession so that the image light exits the polarizing beam splitter and is in-coupled into the waveguide display over the extent of the FOV as the first and second MEMS scanners are operated.

5 more elements

A head mounted display (HMD) device configured to display images within a field of view (FOV) having first and second directions, comprising:

a polarization beam splitter (PBS) cube having twelve edges and six faces including an entrance face and an exit face, the entrance and exit faces sharing a common edge, the PBS cube configured to reflect propagating image light having a first polarization state orthogonally to a direction of propagation and further configured to transmit image light having a second polarization state parallel to the direction of propagation;
an in-coupling diffractive optical element (DOE) in a waveguide display that provides exit pupil expansion in the first and second directions of the FOV, the in-coupling DOE located adjacent to the exit face of the PBS cube;
a first quarter wave plate located adjacent to a face of the PBS cube that is opposite the entrance face;
a second quarter wave plate located adjacent to a face of the PBS cube that is opposite the exit face;
a first MEMS (micro electro mechanical system) scanner having a reflective scanning plate and configured to scan in the first direction of the FOV, the first MEMS scanner located adjacent to the first quarter wave plate;
and
a second MEMS scanner having a reflective scanning plate and configured to scan in the second direction of the FOV, the second MEMS scanner located adjacent to the second quarter wave plate.

4 more elements

A device configured to control image light associated with virtual images within a field of view (FOV), comprising:

an imager configured to produce the image light;
a waveguide display including a polarization-sensitive in-coupling diffractive optical element (DOE) configured to in-couple image light into the waveguide display or transmit image light according to a state of polarization of the image light, at least one intermediate DOE configured to expand an exit pupil of the image light in a first direction of the FOV, and an out-coupling DOE configured to expand the exit pupil of the image light in a second direction of the FOV and further configured to out-couple image light out of the waveguide display to an eye of a user of the device;
a pair of MEMS (micro electro mechanical system) scanners operatively coupled to perform raster scanning of the virtual images in the FOV using the image light from the imager, the MEMS scanners further providing the image light to the in-coupling DOE in the waveguide display;
and
a polarizing beam splitter device configured to direct image light to either a first MEMS scanner in the pair or a second MEMS scanner in the pair according to a state of polarization of the image light.

2 more elements

Dependencies are inferred from the claim text.