Reflective Optical System with Free-Form Mirrors for Wide-Angle Low Distortion
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Solution Overview
Problem
Existing wide-angle optical systems for surveillance cameras and UAVs face challenges in achieving both a wide field of view and reduced distortion while minimizing size, often requiring a large number of lenses, which increases size and cost.
Innovation Solution
The optical system employs a reflection mirror configuration with free-form surface shapes, including an aperture stop and multiple reflection surfaces, where the first and second reflection surfaces have specific angular relationships and shapes to minimize size and aberrations, allowing for a wide angle of view with low distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large number of lenses are used to reduce distortion in a wide-angle optical system, then distortion is reduced, but the size of the optical system increases
Solution Approach 1:
The patent replaces the conventional refractive lens system with a reflective optical system using mirrors. Specifically, it employs a first reflection surface and a second reflection surface to form images, eliminating the need for multiple refractive lenses. This substitution of reflection for refraction allows distortion reduction without increasing system size, as the reflective surfaces can be configured to correct aberrations while maintaining a compact layout.
Solution Approach 2:
The patent utilizes free-form surfaces for the reflection surfaces, which are curved surfaces with complex geometries. The first reflection surface and second reflection surface are designed with specific curvatures to control light paths and reduce distortion. By employing curved reflective surfaces instead of flat or simple spherical surfaces, the system achieves distortion correction in a compact configuration without requiring multiple lenses.
2Volume of moving object
If a wide-angle configuration is achieved with a reduced number of components, then miniaturization is achieved, but distortion increases
Solution Approach 1:
The patent divides the optical system into distinct functional components: an aperture stop, a first reflection surface, and a second reflection surface. Each component performs a specific function in controlling light paths and forming images. The aperture stop controls the cone of light, the first reflection surface performs initial image formation and aberration control, and the second reflection surface completes the image formation. This segmentation allows each component to be optimized for its specific function, achieving distortion reduction in a miniaturized configuration.
Solution Approach 2:
The patent employs asymmetric configuration of the reflection surfaces, where the first reflection surface and second reflection surface have different shapes, orientations, and positions. The angle between the optical axis and the line connecting the aperture stop center to the first reflection surface is specifically designed to be within 45 degrees, creating an asymmetric light path that effectively reduces distortion while maintaining a compact form factor.
3Manufacturing precision
If multiple lenses are used to satisfy both wide angle and low distortion requirements, then image quality is improved, but the number of components and system complexity increase
Solution Approach 1:
The patent replaces the complex multi-lens refractive system with a simpler reflective system consisting of only two reflection surfaces and an aperture stop. This substitution eliminates chromatic aberrations inherent in refractive systems and reduces the total number of components needed to achieve the same or better image quality. The reflective configuration with specifically designed free-form surfaces provides effective aberration control with fewer elements.
Solution Approach 2:
The first reflection surface and second reflection surface are designed to perform multiple functions simultaneously: they form images, control aberrations including distortion, and define the field of view. The aperture stop also serves multiple purposes by controlling light quantity, defining the entrance pupil, and helping to reduce aberrations. This multi-functionality of each component reduces the overall system complexity compared to conventional multi-lens systems where each lens has a more specialized role.
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 compact optical system with high image quality and low distortion across a wide angle of view, reducing the number of lenses needed and maintaining a bright F-number, thus achieving miniaturization and improved imaging performance.
Implementation Method 1
an optical system according to claim 1, a stereo optical system according to claim 5, an image capturing apparatus according to claim 6, a distance measuring apparatus according to claim 7, a vehicle-mounted system according to claim 8, and a moving apparatus according to claim 9 which are capable of reducing distortion while simultaneously achieving a wide angle and miniaturization
Data Source
AI summary
An optical system (L0) that forms an image of an object and that includes an aperture stop (SP), a first reflection surface (R2), and a second reflection surface (R3) which are disposed in order from an enlargement side to a reduction side, an area of the first reflection surface is larger than an area of the second reflection surface, a reference axis is a path of a reference ray that passes through an opening center of the aperture stop to reach a center of a reduction plane, and an angle ∠QPR (deg) between a line segment PQ connecting the opening center P and an intersection Q of the reference axis and the first reflection surface, and a line segment PR connecting the opening center P and an intersection R of the reference axis and the second reflection surface satisfies a predetermined condition.