Aspherical Lens Design for Wide-Angle Projection Systems
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Solution Overview
Problem
Current image forming optical systems face challenges in achieving a wide angle of view while maintaining small size, excellent manufacturability, and favorable optical performance, particularly in correcting aberrations and ensuring easy assembly.
Innovation Solution
The optical system consists of a first and second optical system with an intermediate image, featuring at least one aspherical lens with specific curvature characteristics, and satisfies conditional expressions to optimize lens design, including focal lengths, radii of curvature, and surface shapes to correct distortion and field curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide angle of view is achieved by increasing the maximum image height, then the angle of view is improved, but the system size increases
Solution Approach 1:
The patent employs aspherical lens surfaces with specifically designed curvature profiles to achieve wide angle of view while controlling system size. The aspherical surfaces enable more efficient light ray control compared to spherical surfaces, allowing compact system design with wide angular coverage.
Solution Approach 2:
The patent optimizes multiple optical parameters including focal length ratios, radius of curvature relationships, and aspherical surface coefficients to achieve the desired wide angle of view in a compact form. The conditional expressions define specific parameter ranges that balance angle of view and system size.
2Reliability
If complex lens designs are used to correct aberrations, then optical performance is improved, but manufacturability and assembling property deteriorate
Solution Approach 1:
The patent applies aspherical surfaces only to specific lens locations where they are most effective for aberration correction, rather than making all lenses aspherical. This selective application maintains optical performance while reducing overall manufacturing complexity and cost.
Solution Approach 2:
The patent defines specific parameter ranges for focal lengths, radii of curvature, and aspherical coefficients that balance aberration correction capability with manufacturability. The conditional expressions ensure optimal optical performance while maintaining reasonable manufacturing and assembly requirements.
3Volume of moving object
If the focal length is reduced to make the system smaller, then system size is improved, but the angle of view and optical performance deteriorate
Solution Approach 1:
The aspherical lens surfaces enable compact focal length while maintaining wide angle of view by more efficiently controlling light ray paths. The non-spherical geometry allows for shorter optical paths that would otherwise require longer focal lengths in conventional spherical lens systems.
Solution Approach 2:
The patent transitions from conventional spherical symmetry to aspherical geometry, adding dimensional complexity to the lens surfaces. This enables compact system size while maintaining wide angle capability through sophisticated surface profiling rather than simply scaling down spherical lenses.
4Reliability
If aspherical lenses are used to correct distortion and field curvature, then optical performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies aspherical surfaces selectively to specific lenses where they provide maximum optical benefit, rather than making all lenses aspherical. This reduces the total number of aspherical surfaces that require high-precision manufacturing, thereby balancing optical performance with manufacturing feasibility.
Solution Approach 2:
The patent defines specific parameter ranges for aspherical coefficients and surface curvatures that optimize optical performance while considering manufacturing capabilities. The conditional expressions ensure that the aspherical profiles are not so complex as to be unmanufacturable yet sufficient for effective aberration 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 configuration enables an image forming optical system with a wide angle of view, small size, improved manufacturability, and superior optical performance by effectively correcting aberrations and reducing sensitivity to errors, thus enhancing the assembly and performance of projection type display devices and imaging apparatuses.
Implementation Method 1
the first optical system includes at least one aspherical lens... a specific lens, which is the aspherical lens closest to the intermediate image on the optical path
Data Source
AI summary
An image forming optical system consists of a first optical system and a second optical system in order from a magnification side. An intermediate image is formed between the first optical system and the second optical system. Among the aspherical lenses included in the first optical system, a specific lens, which is the aspherical lens closest to the intermediate image on the optical path, has a meniscus shape of which a surface is convex toward the reduction side in a paraxial region. The image forming optical system satisfies a maximum image height, a focal length, and predetermined conditional expressions for the specific lens.