Transmissive Reflective Optical System for Wide Focus Range
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Solution Overview
Problem
Existing optical systems, such as those disclosed in Japanese Patent Laid-Open No. 2005-352273, face challenges in achieving high optical performance over a wide focus range due to dark F-numbers, reduced light transmission with randomly polarized light, and inadequate suppression of aberrations during focusing or increased imaging magnification.
Innovation Solution
The optical system comprises a first transmissive reflective surface that moves along the optical axis during focusing, a second transmissive reflective surface located closer to the image, and a lens separated from both reflective surfaces. This configuration allows for high image quality over a wide focus range by independently moving the reflective surface with high aberration correction capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a polarizing element and half-mirror are used to create a compact optical system, then the system becomes more compact, but the F-number becomes darker and light transmission is reduced to one-eighth
Solution Approach 1:
The optical system is divided into multiple lens units with specific functions: the first lens unit has positive refractive power and moves during focusing, the second lens unit has negative refractive power and remains stationary, and the third lens unit has positive refractive power and moves during focusing. This segmentation allows each unit to contribute differently to light transmission and focusing, resolving the contradiction between compact size and light transmission.
Solution Approach 2:
The first and third lens units are configured to move in the optical axis direction during focusing, while the second lens unit remains stationary. This dynamic configuration allows the system to maintain high light transmission by optimizing the positions of moving lens units, thereby resolving the contradiction between compact optical system design and sufficient light transmission.
2Volume of moving object
If the optical system uses a dark F-number configuration, then the system becomes more compact, but aberrations cannot be suppressed during focusing and imaging magnification cannot be increased
Solution Approach 1:
Different lens units are assigned different refractive powers and movement characteristics: the first lens unit has positive refractive power and moves during focusing, the second lens unit has negative refractive power and remains stationary, and the third lens unit has positive refractive power and moves during focusing. This local differentiation of optical properties allows each unit to contribute specifically to aberration correction while maintaining compact size.
Solution Approach 2:
The first and third lens units are configured to move in the optical axis direction during focusing, while the second lens unit remains stationary. This dynamic configuration enables effective aberration suppression across the focusing range while maintaining a compact optical system structure.
3Manufacturing precision
If the lens is separated from both transmissive reflective surfaces, then aberration correction is improved, but the device complexity increases
Solution Approach 1:
The optical system is divided into three distinct lens units separated by air gaps, with the first and third units moving during focusing and the second unit remaining stationary. This segmentation into functionally distinct units improves aberration correction while keeping the overall structure manageable through clear functional separation.
Solution Approach 2:
The first and third lens units serve multiple functions: they contribute to the overall optical power of the system, enable focusing by moving during focusing, and assist in aberration correction. This multi-functionality reduces the need for additional dedicated elements, thereby limiting the increase in device complexity despite the separated configuration.
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 described optical system achieves high image quality over a wide focus range and large apertures, effectively addressing the limitations of existing systems by improving light transmission and aberration suppression.
Implementation Method 1
a first transmissive reflective surface HM1, a second transmissive reflective surface HM2
Implementation Method 2
a first refractive lens L1, a second refractive lens L2, a third refractive lens L3
Data Source
AI summary
An optical system includes a first transmissive reflective surface, a second transmissive reflective surface located closer to an image than the first transmissive reflective surface, and a lens located closer to an object than the first transmissive reflective surface or closer to the image than the second transmissive reflective surface. The first transmissive reflective surface is configured to move in an optical axis direction during focusing. The lens is separated from each of the first transmissive reflective surface and the second transmissive reflective surface.