Tilted Pin-Mirror AR Combiner for Wide Field of View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current augmented reality (AR) glasses face challenges with large size, bulkiness, high cost, limited functionality, and difficulties in achieving wide field of view (FOV) due to complex optical designs, as well as issues with image focusing and blur circles caused by diffraction and interference effects.
Innovation Solution
The use of a pin-mirror based combiner with tilted pin-mirrors embedded between the inner and outer surfaces, allowing ambient light to pass through while directing image light to an eye box, and a tri-linear display with scanning projection and pixel illumination schemes to enhance brightness and resolution, reducing the blur circle and improving optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a curved combiner is used to redirect image light to the eye box, then the field of view can be expanded, but the device size and complexity increase significantly
Solution Approach 1:
The combiner surface is segmented into multiple flat facets instead of using a single curved surface. Each facet redirects light from a specific angular range to the eye box, collectively providing a wide field of view while maintaining flat, manufacturable components.
Solution Approach 2:
The solution transitions from a two-dimensional curved surface to a three-dimensional arrangement of multiple flat facets at different orientations. This allows the system to achieve the light-redirection capabilities of a curved combiner while using flat, easier-to-manufacture components.
2Area of stationary object
If a curved combiner is used to achieve wide field of view, then the FOV is improved, but the device becomes bulky and difficult to fit on temples
Solution Approach 1:
The combiner is divided into multiple flat facets that can be arranged in a compact configuration. This segmentation allows the wide FOV functionality to be achieved with a smaller overall device volume that can be comfortably fitted on temples.
3Volume of moving object
If diffraction gratings are used for light coupling in waveguides, then the device size is reduced, but chromatic and stray light artifacts are introduced
Solution Approach 1:
The patent replaces the diffractive optical elements (gratings) with a reflective optical system using flat facets and mirrors. This substitution eliminates the chromatic dispersion and stray light artifacts inherent to diffraction-based light coupling while maintaining compact device dimensions.
4Illumination intensity
If the pupil aperture is enlarged to increase light gathering, then more light reaches the retina, but the blur circle size increases reducing image quality
Solution Approach 1:
The combiner is divided into multiple facets, each directing light from a specific angular range to a corresponding region of the pupil. This segmentation allows the system to utilize the full pupil aperture for light gathering while maintaining image sharpness by preventing blur circle formation through precise angular control.
Solution Approach 2:
Different facets of the combiner are optimized for different angular ranges, with each facet directing light to a specific region of the pupil. This local optimization allows the system to maximize light transmission while maintaining image quality across the entire pupil aperture.
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
This solution enables a more compact, cost-effective, and high-resolution AR headset with improved image focus and reduced blur circles, allowing for a wider FOV and better integration of virtual and real-world images.
Implementation Method 1
A plurality of tilted pin-mirrors imbedded between an inner surface and an outer surface of the combiner, where the plurality of tilted pin-mirrors are configured to reflect the guided image light towards the eye box
Data Source
AI summary
Augmented reality headsets. A plurality of tilted pin-mirrors imbedded between an inner surface and an outer surface of a combiner, where the plurality of tilted pin-mirrors are configured to reflect the guided image light towards the eye box, and wherein the plurality of pin-mirrors include one or more gaps between them wherein the one or more gaps allow the passage of an ambient light through the combiner towards the eye box.