Waveguide Beam Angle Sensor for AR VR Image Distortion
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Solution Overview
Problem
Existing virtual and augmented reality systems face challenges in ensuring that the actual angles of light rays exiting the waveguide of a display subsystem match the designed angles encoded in the image data, leading to image distortion due to manufacturing tolerances and environmental changes.
Innovation Solution
A display subsystem that includes a waveguide apparatus with embedded diffractive optical elements, a sensing assembly with angle sensors to detect the actual angles of exiting light rays, and a control subsystem to adjust the light beam angles based on the sensed parameters, ensuring accurate pixel placement and minimizing image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manufacturing tolerances and environmental changes are not compensated, then device complexity is reduced, but image distortion increases due to mismatch between actual and designed light ray angles
Solution Approach 1:
The patent implements a feedback mechanism where angle sensors detect the actual angles of light rays exiting the waveguide, and this information is fed back to a control subsystem that adjusts the light beam angles accordingly. This closed-loop feedback system compensates for manufacturing tolerances and environmental changes, maintaining accurate pixel placement without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The system performs self-calibration and self-correction by using the angle sensors to automatically detect and measure deviations in light ray angles, then using this information to adjust the projection subsystem. This self-service approach eliminates the need for external calibration equipment or manual adjustment mechanisms.
2Manufacturing precision
If angle sensors and control subsystems are added, then image distortion is reduced, but device complexity increases
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with an optical-electrical control system. Instead of using movable mechanical components to adjust light beam angles, the system uses angle sensors to detect deviations and electrical control signals to adjust the projection subsystem, eliminating complex mechanical adjustment mechanisms while maintaining or improving precision.
Solution Approach 2:
The angle sensors serve multiple functions: they detect the actual angles of light rays for feedback control, and they provide information for both horizontal and vertical angle compensation. This multi-functionality reduces the need for separate sensing and control mechanisms for each degree of freedom.
3Reliability
If light beam angles are dynamically adjusted, then image distortion is minimized, but ease of operation decreases due to additional control requirements
Solution Approach 1:
The system automatically adjusts light beam angles based on sensor feedback without requiring user intervention. The control subsystem autonomously processes sensor data and implements corrections, making the system self-regulating and eliminating the need for manual calibration or adjustment by the operator.
Solution Approach 2:
The continuous feedback loop between angle sensors and the control subsystem ensures that image quality is maintained automatically. The system constantly monitors light ray angles and makes real-time adjustments, providing reliable and consistent image quality without requiring user attention or manual control.
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 solution effectively maintains the accuracy of light ray angles, thereby ensuring that pixels are displayed at their correct locations within the field of view, reducing image distortion and enhancing the overall immersion and clarity of virtual and augmented reality experiences.
Implementation Method 1
One or more linear diffraction gratings are embedded within the waveguide(s) to change the angle of incident light propagating along the waveguide(s). 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).
Implementation Method 2
The display subsystem may further comprise one or more collimation elements that collimate light coming from the optical fiber(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 virtual image generation system for use by an end user comprises a projection subsystem configured for generating a collimated light beam, and a display configured for emitting light rays in response to the collimated light beam to display a pixel of an image frame to the end user. The pixel has a location encoded with angles of the emitted light rays. The virtual image generation system further comprises a sensing assembly configured for sensing at least one parameter indicative of at least one of the emitted light ray angles, and a control subsystem configured for generating image data defining a location of the pixel, and controlling an angle of the light beam relative to the display based on the defined location of the pixel and the sensed parameter(s).