Macro Optical System with Segmented Focus Lens Units
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Solution Overview
Problem
Existing macro lenses face challenges in maintaining high optical performance and minimizing aberration fluctuations while avoiding large actuators that compromise focusing accuracy and speed.
Innovation Solution
The optical system comprises a configuration with a first lens unit and a final lens unit fixed relative to the image plane, and focus lens units on either side of an aperture stop that move during focusing, ensuring an increased absolute value of imaging magnification and adhering to specific inequalities to optimize lens length and refractive power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large focus lens unit is used to correct aberration fluctuations during focusing, then aberration correction is improved, but the actuator size increases and focusing speed decreases
Solution Approach 1:
The focus lens unit is divided into multiple lens elements (positive and negative lenses) arranged in specific configurations. This segmentation allows each element to contribute differently to aberration correction while keeping the overall moving mass smaller, thus maintaining focusing speed without sacrificing correction effectiveness
Solution Approach 2:
Different lens elements within the focus lens unit have different refractive powers and positions optimized for specific aberration corrections. The positive and negative lenses are strategically positioned to address different types of aberrations locally, achieving comprehensive correction with smaller individual components
2Reliability
If a large focus lens unit is used to correct aberration fluctuations during focusing, then aberration correction is improved, but the actuator size increases and focusing accuracy deteriorates
Solution Approach 1:
The focus lens unit is segmented into multiple smaller lens elements rather than one large element. This reduces the overall size and mass of the moving assembly, enabling more precise positioning by the actuator and improving focusing accuracy while maintaining aberration correction capabilities
Solution Approach 2:
The patent optimizes specific parameters including the ratio of positive to negative lens powers, the distances between lens elements, and the position of the aperture stop relative to the focus lens unit. These parameter adjustments enable effective aberration correction with a compact focus lens unit that maintains high focusing accuracy
3Reliability
If the overall lens length is increased to improve optical performance, then aberration correction is improved, but the system becomes less compact
Solution Approach 1:
The optical system employs a nested arrangement where the aperture stop is positioned within or near the focus lens unit assembly, and lens elements are closely integrated. This nesting allows multiple functional components to occupy overlapping or adjacent spaces, achieving comprehensive optical correction without proportionally increasing the overall lens length
Solution Approach 2:
The patent optimizes the three-dimensional arrangement of lens elements and the aperture stop, utilizing depth and lateral positioning strategically. By carefully controlling distances in the optical axis direction and lateral offsets, the design achieves effective aberration correction while maintaining a compact overall form factor
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 reduces the weight and size of focus lens units, improves focusing accuracy and speed, and provides a compact, high-performance optical system with enhanced aberration correction.
Implementation Method 1
The final lens unit includes a positive lens and a negative lens
Data Source
AI summary
An optical system includes, in order from an object side to an image side, first to fourth lens units. A distance changes between adjacent lens units during focusing from infinity to a close distance. The optical system includes an aperture stop disposed on the image side of the second lens unit, a final lens unit, the first lens unit and the final lens unit being fixed relative to the image plane during the focusing, and focus lens units disposed on the object side and the image side of the aperture stop. A focus lens unit closest to the image plane among the focus lens units moves toward the image side during the focusing. The optical system is configured to increase an absolute value of an imaging magnification at a shortest imaging distance to 0.5 times or higher. The final lens unit includes positive and negative lenses. A predetermined condition is satisfied.