Anamorphic Reflective Surface for Astigmatism Correction in AR/VR Displays
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Solution Overview
Problem
Electronic devices used in Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR) face challenges with dual image formation due to astigmatism in off-axis optical systems, making it difficult to achieve clear virtual image projection over real-world images.
Innovation Solution
The electronic device incorporates a display unit with a lens unit and a reflective surface having different curvatures in the Rx and Ry directions to correct astigmatism, featuring a 3-dimensional curved surface that can be concave or anamorphic, and includes optical elements like pin mirrors to adjust the image light path, ensuring clear image transmission to the user's eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a reflective surface with uniform curvature is used in the lens unit, then the manufacturing process is simple, but astigmatism occurs causing dual image formation
Solution Approach 1:
The reflective surface is designed with different curvatures in different directions (first curvature in first direction, second curvature in second direction perpendicular to first direction). This local variation in surface properties corrects astigmatism by compensating for the different optical paths of light rays in different meridians, eliminating dual image formation while maintaining manufacturing feasibility through controlled surface shaping.
Solution Approach 2:
The reflective surface employs asymmetric curvature design where the curvature radius differs between the first direction and the second direction. This asymmetric configuration specifically addresses the astigmatism problem caused by the off-axis optical system, creating a single focused image by balancing the optical path differences in orthogonal directions.
2Device complexity
If an off-axis optical system is used to project virtual images, then the device structure is compact, but astigmatism causes dual image formation
Solution Approach 1:
The optical system parameters are optimized by setting specific relationships between the curvature radius of the reflective surface and the focal length of the lens. The curvature radius is designed to be within a specific range relative to the focal length, which corrects astigmatism while maintaining the compact off-axis structure. This parameter optimization ensures single image formation without compromising the compact design.
3Length of moving object
If the curvature radius of the reflective surface is too small, then the optical path is shortened, but astigmatism correction is insufficient
Solution Approach 1:
The curvature radius of the reflective surface is optimized within a specific range that balances optical path length and astigmatism correction effectiveness. By setting the curvature radius to an appropriate value relative to the lens focal length, the design achieves sufficient astigmatism correction while maintaining a compact optical path, avoiding both excessive length and insufficient correction.
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 effectively addresses the dual image problem caused by astigmatism, providing a clear and stable virtual image overlay on real-world images by adjusting the reflective surface curvatures and optical element placement, enhancing the overall user experience in VR, AR, and MR environments.
Implementation Method 1
a display unit for reflecting the image light of the light emitting unit and transmitting the reflected image light to eyes of a user
Implementation Method 2
a lens unit for transmitting the image light transmitted from the light emitting unit
Implementation Method 3
The reflective surface is formed of a 3-dimensional curved surface having different curvatures in a first direction and in a second direction perpendicular to the first direction, thereby correcting astigmatism
Data Source
AI summary
An electronic device is disclosed. The electronic device of the present disclosure includes a light emitting unit for providing image light, and a display unit for reflecting the image light and transmitting the reflected image light to eyes of a user. The display unit includes a lens unit and a reflective surface for reflecting the image light. The reflective surface is formed of a 3-dimensional curved surface having different curvatures in a first direction and in a second direction perpendicular to the first direction, thereby correcting astigmatism. An electronic device according to the present invention may be associated with an artificial intelligence module, robot, augmented reality (AR) device, virtual reality (VR) device, and device related to 5G services.