Anamorphic Waveguide Illumination for Wide-FOV Near-Eye Displays
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Solution Overview
Problem
Existing near-eye display apparatuses face challenges in providing high-resolution, high-luminance, wide-field-of-view images with reduced glare and stray light, while maintaining a compact form factor and low weight, particularly in augmented reality (AR) displays.
Innovation Solution
An anamorphic near-eye display apparatus with an optical system featuring a spatial light modulator, transverse and lateral anamorphic components, and an extraction waveguide with reflective features that provide anamorphic properties, enhancing image brightness, efficiency, and eyebox size, while reducing chromatic aberrations and stray light artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a waveguide optical system is used to reduce form factor and weight, then compactness and portability are improved, but achieving wide field of view with high brightness and large eyebox becomes more difficult
Solution Approach 1:
The patent applies anamorphic optical properties that treat lateral and transverse directions differently. The waveguide has different optical powers in lateral and transverse directions, allowing independent optimization of field of view in each direction. This dimensional differentiation enables achieving wide field of view and high brightness simultaneously within a compact waveguide structure.
Solution Approach 2:
The patent changes optical parameters by introducing anamorphic components with specific optical powers (PL and PT) in different directions. By adjusting these anamorphic parameters and the distribution of extraction features, the system optimizes brightness, field of view, and eyebox size independently, resolving the contradiction between compactness and illumination intensity.
2Ease of operation
If extraction features are added to the waveguide to increase eyebox size, then ease of operation is improved, but chromatic aberrations and stray light artifacts increase
Solution Approach 1:
The patent distributes extraction features non-uniformly along the waveguide length, with different extraction efficiencies at different positions. This local quality variation allows optimization of eyebox size in specific regions while minimizing chromatic aberrations in other regions. The anamorphic optical properties further differentiate extraction characteristics in lateral versus transverse directions.
3Length of stationary object
If the waveguide is made thinner to reduce form factor, then compactness is improved, but the ability to guide light efficiently over wide angles deteriorates
Solution Approach 1:
The patent compensates for reduced waveguide thickness by introducing anamorphic optical properties with different powers in lateral and transverse directions. This allows the thinner waveguide to maintain effective light guidance by optimizing the optical path in the transverse direction while keeping the lateral dimension compact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The anamorphic near-eye display apparatus achieves wide field of view, high brightness, and large eyebox with reduced color blur and glare, suitable for AR and VR applications, while maintaining a compact size and low weight.
Implementation Method 1
the extraction waveguide comprises an array of reflective extraction features disposed internally within the extraction waveguide, the reflective extraction features arranged to transmit light guided along the extraction waveguide in the first direction and to extract light guided along the extraction waveguide in the second direction
Implementation Method 2
a light reversing reflector that is arranged to reflect light that has been guided along the extraction waveguide in the first direction so that the reflected light is guided along the extraction waveguide in a second direction opposite to the first direction
Implementation Method 3
a transverse anamorphic component having positive optical power in the transverse direction, wherein the transverse anamorphic component is arranged to receive light from the spatial light modulator and the illumination system is arranged so that light output from the transverse anamorphic component is directed in directions that are distributed in the transverse direction
Data Source
AI summary
An anamorphic near-eye display apparatus comprises a spatial light modulator with asymmetric pixels; an input transverse anamorphic lens; and an extraction waveguide that passes input light in a first direction to a lateral anamorphic reflector arranged to reflect the light back through the waveguide. Partially reflective extraction elements are arranged between the rear and front guide surfaces of the waveguide to extract the reflected light towards the pupil of an observer, maintaining the directionality of the fan of light rays from the spatial light modulator and anamorphic imaging system. A thin, transparent and efficient anamorphic display apparatus for Augmented Reality and Virtual Reality displays is provided.