Compact Schmidt-Cassegrain Optical System for Miniaturized Imaging
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Solution Overview
Problem
Current imaging apparatuses using reflection optical systems are limited in size reduction, necessitating further miniaturization while maintaining effective image formation and aberration correction.
Innovation Solution
The development of a Schmidt-Cassegrain-type optical system with a compact design, incorporating a correction plate, primary and secondary reflection mirrors, and a refractive optical system, which reduces the optical path length and aberrations, allowing for a more compact form factor while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a reflection optical system is used, then the size of the imaging apparatus is reduced, but further size reduction is required to meet miniaturization demands
Solution Approach 1:
The patent combines refractive and reflective optical systems into a hybrid configuration. The refractive lens assembly (including first and second lens groups) works in conjunction with reflection surfaces (first and second reflection surfaces) to achieve compact image formation. This merging allows the system to benefit from both refractive focusing and reflective path folding, enabling further size reduction beyond what pure reflection systems achieve.
Solution Approach 2:
The optical system employs a nested arrangement where the second reflector is positioned within the optical path defined by the first reflector, and lens groups are arranged in nested configurations along the optical axis. This nesting allows multiple optical elements to occupy overlapping or adjacent spatial volumes, maximizing space utilization and minimizing the overall footprint of the imaging apparatus.
2Length of stationary object
If the optical path length is reduced for miniaturization, then the size decreases, but image quality and aberration correction may deteriorate
Solution Approach 1:
The patent applies different optical properties to different regions of the system. The first and second lens groups have different refractive indices and focal lengths, allowing optimization for specific portions of the optical path. The reflection surfaces are positioned at specific locations to correct aberrations locally while maintaining overall compactness. This localized optimization ensures that even with reduced optical path length, image quality and aberration correction are maintained.
Solution Approach 2:
The system utilizes multiple reflectors and lens groups with varying optical parameters (refractive indices, focal lengths, curvature radii) to correct aberrations. By carefully selecting and adjusting these parameters, the patent achieves effective aberration correction despite the compact optical path length. The conditional expressions define specific parameter ranges that ensure both miniaturization and image quality.
3Volume of moving object
If multiple reflectors are added to reduce size, then the optical path is folded more effectively, but the device complexity increases
Solution Approach 1:
The patent designs the optical system where components serve multiple functions. The refractive lens groups not only focus light but also work in conjunction with the reflection surfaces to fold the optical path. The first and second reflectors are integrated into the same optical train, allowing a single compact structure to achieve both path folding and image formation without requiring separate subsystems. This multi-functionality reduces overall device complexity despite the presence of multiple optical elements.
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
The compact Schmidt-Cassegrain-type optical system achieves a significant reduction in size, with a total length from the object side to the image plane of less than 15 mm and a half-angle of view greater than 10 degrees, enabling efficient image formation and aberration correction, resulting in a high-resolution, miniaturized imaging apparatus.
Implementation Method 1
a first reflector that reflects the light having passed through the light incident surface
Implementation Method 2
a second reflector that reflects the light reflected off the first reflector
Implementation Method 3
A medium in an optical path between the first reflector and the second reflector is a light transmissive member having a refractive index
Data Source
AI summary
There are provided an optical system having high resolution and high optical performance and reduced in size, an optical apparatus including the optical system, an imaging apparatus, and a method for manufacturing the optical system and imaging apparatus. An optical system UL of a camera module 10, which is incorporated in an optical apparatus, such as a camera 60, is an optical system that forms an image of an object, includes a correction member having a correction surface 11a, a first reflection surface 12a, which reflects light having passed through the correction surface 11a, and a second reflection surface 13a, which reflects the light reflected off the first reflection surface 12a, and satisfies predetermined conditions.