Inward Pointing Angles for Compact Fiber Scanner Waveguide
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Solution Overview
Problem
Existing virtual and augmented reality display systems face challenges in reducing the size of optical coupling elements, which increases the complexity and size of the waveguide apparatus due to large deflections of optical fibers, affecting the overall size and efficiency of the display system.
Innovation Solution
The display subsystem incorporates a planar waveguide apparatus with a mechanical drive assembly and diffractive optical elements, where the optical fiber is affixed to the waveguide, and a collimation element is used to converge light inward to a focal point, minimizing the size of optical coupling elements and enhancing the display system's efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical fibers are allowed to have large deflections to enable scanning, then the scanning capability is improved, but the size of optical coupling elements must increase to accommodate the larger span of scanned collimated light
Solution Approach 1:
The optical coupling element is divided into multiple sections corresponding to different deflection angles of the optical fiber. Each section has a different inward pointing angle configured to receive collimated light at specific angles, allowing the element to handle large scanning deflections while maintaining a compact overall size.
Solution Approach 2:
Different portions of the optical coupling element are configured with different inward pointing angles optimized for specific regions of the scanning pattern. This local optimization allows each section to efficiently couple light at its designated angle range, reducing the total size required compared to a uniform design.
2Volume of stationary object
If the size of optical coupling elements is reduced, then the overall display system size is decreased, but the complexity of the waveguide apparatus increases
Solution Approach 1:
Multiple optical coupling elements with different inward pointing angles are integrated into a single waveguide apparatus structure. This merging approach consolidates what would otherwise be separate components, reducing overall system size while managing complexity through unified design and alignment.
Solution Approach 2:
The optical coupling elements are arranged in a three-dimensional configuration within the waveguide apparatus, utilizing spatial distribution along the optical axis and lateral dimensions. This dimensional arrangement allows compact integration of multiple coupling functions without increasing the apparent two-dimensional footprint.
3Area of stationary object
If collimation elements are used to converge light inward to a focal point, then the size of optical coupling elements is minimized, but the alignment precision requirements increase
Solution Approach 1:
The collimation element is positioned upstream in the optical path to pre-converge light to a focal point before it reaches the optical coupling element. This preliminary action creates a more compact beam footprint at the coupling element, reducing its size while the focal point geometry provides natural alignment references that tolerate moderate manufacturing variations.
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 configuration reduces the size and complexity of optical coupling elements, allowing for a more compact and efficient virtual or augmented reality display system that provides high-quality, three-dimensional image rendering with reduced size and increased image quality.
Implementation Method 1
The display system may further comprise one or more collimation elements that collimate light coming from the optical fiber(s)
Implementation Method 2
One or more linear diffraction gratings are embedded within the waveguide(s) to change the angle of incident light propagating along the waveguide(s)
Implementation Method 3
By changing the angle of light beyond the threshold of total internal reflection (TIR), the light escapes from one or more lateral faces of the waveguide(s)
Data Source
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AI summary
A display subsystem for a virtual image generation system. The display subsystem comprises a planar waveguide apparatus, and an optical fiber having a distal tip affixed relative to the planar waveguide apparatus, and an aperture proximal to the distal tip. The display subsystem further comprises at least one light source coupled the optical fiber and configured for emitting light from the aperture of the optical fiber, and a mechanical drive assembly to which the optical fiber is mounted to the drive assembly. The mechanical drive assembly is configured for displacing the aperture of the optical fiber in accordance with a scan pattern. The display subsystem further comprises an optical waveguide input apparatus configured for directing the light from the aperture of the optical fiber down the planar waveguide apparatus, such that the planar waveguide apparatus displays one or more image frames to the end user.