Dual-Stop Optical System for Compact Imaging and Edge-Light Control
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Solution Overview
Problem
Existing optical systems face challenges in improving image forming performance at intermediate image heights while reducing size and maintaining light quantity in the edge part of the image.
Innovation Solution
An optical system with a first stop having a variable opening diameter and three or more lenses, including positive and negative lenses, and a second stop with a fixed opening diameter, where specific conditional expressions are satisfied to optimize the distance, opening diameters, and lens surface positions, allowing the second stop to move or be fixed during focusing or magnification changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stop is added to restrict off-axis rays for improving image forming performance at intermediate image height, then image quality improves, but the device complexity and size increase
Solution Approach 1:
The patent combines the flare stopper function with existing lens groups or stops in the optical system. Specifically, one embodiment integrates the flare stopper with a focusing lens group, while another embodiment positions it coincident with an existing aperture stop, thereby achieving flare restriction without adding independent structural complexity
Solution Approach 2:
The flare stopper is designed to serve multiple functions: it restricts off-axis rays to improve image forming performance at intermediate image heights, while simultaneously being integrated into the existing optical path control mechanism. The stopper works together with the aperture stop and lens groups to achieve both flare control and maintained light quantity
2Manufacturing precision
If the opening diameter of the flare stopper is reduced to restrict off-axis rays, then image forming performance improves, but the light quantity in the edge part of the image decreases
Solution Approach 1:
The flare stopper is strategically positioned at specific locations in the optical path (either with focusing lens groups or coincident with aperture stops) to selectively restrict only the harmful off-axis rays that cause flare, while allowing on-axis and near-axis rays to pass through. This localized restriction maintains light quantity in the image edge parts while improving image forming performance
3Manufacturing precision
If the distance between the first stop and second stop is increased to improve image forming performance, then aberration control improves, but the optical system size increases
Solution Approach 1:
The patent positions the flare stopper (second stop) at a distance Dst from the aperture stop (first stop) that is optimized to satisfy conditional expression (1), creating a compact nested arrangement where the stopper is integrated into the existing optical path without requiring additional space. This nested positioning achieves effective aberration control while maintaining a compact optical system size
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 enhances image forming performance at intermediate image heights while reducing the size of the optical system and preventing a decrease in light quantity in the edge part of the image.
Implementation Method 1
three or more lenses which are disposed on an object side with respect to the first stop and which include a positive lens and a negative lens
Data Source
AI summary
An optical system includes a first stop having a variable opening diameter, three or more lenses that are disposed on an object side with respect to the first stop and that include a positive lens and a negative lens, and a second stop having a fixed opening diameter, in which, in a case where a distance on an optical axis from the first stop to the second stop is denoted by Dst, and a focal length of the optical system is denoted by f, a conditional expression represented by 0.005<|Dst|/f<2 is satisfied.