Nonaxisymmetric Aspheric Surface for Compact Virtual Image Display
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Solution Overview
Problem
Existing virtual image display apparatuses face challenges in reducing size while maintaining optical precision, due to constraints such as total reflection conditions, aberration suppression, and angle of view requirements, which limit the size reduction of optical systems in head-mounted displays and similar devices.
Innovation Solution
The use of a light guide member with nonaxisymmetric curved surfaces and a projection system featuring at least one nonaxisymmetric aspheric surface, positioned to prevent light components from intersecting, allows for further size reduction of the optical system by optimizing the optical path and reducing the length of the light guide member and projection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a light guide member with nonaxisymmetric curved surfaces and a projection system with nonaxisymmetric aspheric surfaces are used, then the size of the optical system is reduced, but the optical precision and aberration suppression become more difficult to maintain
Solution Approach 1:
The patent applies asymmetry by using nonaxisymmetric curved surfaces in the light guide member and nonaxisymmetric aspheric surfaces in the projection system. These asymmetric surfaces are specifically designed to correct aberrations while enabling compact optical paths, allowing size reduction without sacrificing optical precision. The asymmetric geometry allows optimized light routing that maintains image quality despite the reduced form factor.
Solution Approach 2:
The patent employs parameter changes by carefully designing the curvature radii, surface shapes, and positional parameters of the nonaxisymmetric surfaces. By optimizing these geometric parameters, the system achieves both compact size and high optical precision. The specific parameter values are tuned to balance aberration suppression with the reduced optical path length enabled by the asymmetric configuration.
2Length of moving object
If the length of the light guide member and projection system is shortened, then the overall apparatus size is reduced, but the total reflection condition and aberration suppression become more constrained
Solution Approach 1:
The nonaxisymmetric curved surfaces are designed with asymmetric curvature distributions that enable effective total reflection within a shorter length. The asymmetric geometry allows light to be reflected at optimized angles that maintain the total reflection condition even when the optical path is compressed, thereby preserving reliability while reducing size.
Solution Approach 2:
The patent utilizes curved surfaces with specific curvature characteristics to maintain total reflection conditions in a compact configuration. The nonaxisymmetric aspheric surfaces and curved light guide surfaces are designed with optimized curvature radii that enable light to follow the required optical path while maintaining total reflection, even in the shortened apparatus.
3Volume of moving object
If a compact optical system is designed, then the apparatus becomes more stylish and aesthetically pleasing, but the angle of view and eye ring diameter may be compromised
Solution Approach 1:
The nonaxisymmetric surfaces are designed to expand the angle of view in specific directions while maintaining a compact overall form. The asymmetric geometry allows the optical system to capture and redirect light from a wider field of view into the user's eye, enabling a larger effective angle of view despite the reduced apparatus size.
Solution Approach 2:
The patent uses dimensional optimization by carefully designing the three-dimensional configuration of the nonaxisymmetric surfaces. By manipulating the spatial arrangement and surface geometry in multiple dimensions, the system achieves a compact form factor while maintaining adequate angle of view and eye ring diameter through optimized light path folding and surface curvature in different spatial directions.
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 enables a more compact virtual image display apparatus with maintained optical precision, resolution, and angle of view, allowing for a stylish and aesthetically pleasing design while ensuring high-quality image formation and see-through observation capabilities.
Implementation Method 1
a light guide member that guides the video image light from the video device based on total reflection that occurs at a plurality of surfaces including a nonaxisymmetric curved surface
Data Source
AI summary
In a projection system, a nonaxisymmetric aspheric surface is used as a surface that is located in a position where in a pencil of light of video image light that exits from each of two points in different corner regions in an image plane that is a light exiting plane of an image display apparatus, light components that should reach a viewer's eyes do not intersect one another, whereby the size of an optical system can be further reduced and the size of an overall apparatus can therefore be reduced with a variety of types of optical precision, such as the resolution and angle of view, maintained.