Fixed-Focal Optical Lens Layout for Lightweight Internal Focusing
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Solution Overview
Problem
Existing optical systems face challenges in balancing weight, size, and optical performance during focusing, particularly in maintaining aberration control and refractive power distribution across lens units, which are exacerbated by temperature fluctuations and material dispersion effects.
Innovation Solution
An optical system design that includes a first lens unit with positive refractive power and a second lens unit with negative refractive power, where the second lens unit moves during focusing, adhering to specific inequalities to optimize focal length, Abbe number, and specific gravity ranges, thereby reducing weight and moving amount while enhancing optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the second lens unit moves during focusing to achieve focusing function, then the focusing capability is improved, but the weight and moving amount of the lens unit increase
Solution Approach 1:
The patent applies parameter changes by optimizing the Abbe number and specific gravity of lens materials within defined ranges. By selecting materials with specific optical parameters (Abbe number between 20-40) and density characteristics, the system achieves effective focusing while minimizing the weight and moving amount of the second lens unit, directly resolving the contradiction between focusing capability and weight reduction.
2Ease of operation
If the second lens unit moves during focusing to achieve focusing function, then the focusing capability is improved, but the size of the lens unit increases
Solution Approach 1:
The patent utilizes parameter changes by controlling the focal length ratio (f2/f) within specific ranges and optimizing material parameters (Abbe number, specific gravity). These parameter optimizations enable the second lens unit to achieve focusing functionality with reduced size and volume, resolving the contradiction between focusing capability and compact design.
3Manufacturing precision
If lens units are designed with specific refractive powers to maintain optical performance, then aberration control is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the optical system into distinct lens units (first lens unit with positive refractive power, second lens unit with negative refractive power) with specific functions. The second lens unit is further segmented into multiple lenses with specific Abbe numbers and specific gravities, allowing independent optimization of each segment to control aberrations while managing overall system complexity.
Solution Approach 2:
The patent implements local quality by assigning specific optical characteristics to different lens units and individual lenses. Each lens unit has designated refractive power, and individual lenses within units have specified Abbe numbers and specific gravities. This localized optimization enables precise aberration control in critical areas while maintaining simpler designs in other regions.
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 system achieves reduced weight and size with improved aberration control, including suppression of chromatic and spherical aberrations, while maintaining high optical performance across varying focus distances.
Implementation Method 1
an optical system for imaging... includes, in order from an object side to an image side, a first lens unit with positive refractive power, and a second lens unit with negative refractive power
Data Source
AI summary
Optical systems and image pickup apparatuses are provided herein. One or more optical systems may include, in order from an object side to an image side, a first lens unit with positive refractive power, and a second lens unit with negative refractive power. The optical system may be a fixed focal length lens. Each distance between adjacent lens units changes during focusing. During focusing, the first lens unit does not move and the second lens unit may move. Predetermined inequalities may be satisfied.