Off-Axis Display Assembly with Telecentric Light Control
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Solution Overview
Problem
Existing off-axis display systems for virtual and augmented reality struggle to provide optimal telecentricity, focal depth, and wide field of view, leading to eye strain and discomfort due to varying focal distances and non-parallel light rays, which complicates the user's visual accommodation and perception of virtual content.
Innovation Solution
The arrangement of light sources and optical elements in the display system, including specific angles and shapes of reflective surfaces, ensures that only parallel light rays are reflected to the user's eyes, creating a perceived virtual image within a flat focal plane at a desired range (0.4 to 1.1 meters), optimizing telecentricity and reducing eye strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional off-axis display systems are used, then the system structure is simpler, but telecentricity is poor and focal depth is inconsistent leading to eye strain
Solution Approach 1:
The optical system is divided into multiple independent optical units, each containing a light source and optical element paired for specific eyes. This segmentation allows independent optimization of each unit's telecentricity and focal depth without complicating the entire system, thereby improving visual comfort while managing complexity.
Solution Approach 2:
Each optical unit is designed with specific local optical properties including tilted light sources at angle θ1, tilted optical elements at angle θ2, and specifically shaped reflective surfaces (bi-conic, bi-conic Zernike, extended polynomial, or freeform). These localized optimizations ensure telecentric light delivery and consistent focal depth at each eye position, improving overall visual comfort.
2Area of stationary object
If the field of view is widened, then the coverage area increases, but the image quality and focus consistency deteriorate
Solution Approach 1:
The reflective surfaces of optical elements are designed with specific curved geometries including bi-conic, bi-conic Zernike, extended polynomial, or freeform shapes. These curved surfaces enable wide field of view coverage while maintaining consistent focal depth and image quality across the entire field by properly directing light rays to the user's eyes.
3Measurement precision
If the focal plane is made flat at a specific range, then the perceived depth accuracy improves, but the system complexity increases
Solution Approach 1:
The system achieves a flat perceived focal plane at distances greater than 0.4 meters and less than 1.1 meters by optimizing specific parameters: the tilt angle θ1 of light sources, the tilt angle θ2 of optical elements, and the shapes of reflective surfaces. These parameter optimizations create telecentric light paths that maintain consistent focal depth across the field of view, improving depth accuracy while the modular design keeps system complexity manageable.
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 provides a comfortable and immersive VR or AR experience by maintaining a consistent focal distance within a suitable range for interaction, minimizing eye strain and blurring, and enhancing the perception of virtual content as being located in a real-world environment.
Implementation Method 1
at least one optical element tilted at a second angle θ2 relative to the optical axis having a specified shape C and arranged relative to the light source to reflect the emitted light at a corresponding eye of user
Data Source
AI summary
Aspects of the disclosed apparatuses, methods, and systems provide arrangement of the visual components of an augmented or virtual display system with optimized telecentricity, focal depth, and wide FOV. The visual components may include a light source and a corresponding optical element.