Lens System Aberration Control via Dual-Unit Movement
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Solution Overview
Problem
Existing optical systems for imaging apparatuses face challenges in achieving high-speed focusing while minimizing variations in aberrations and maintaining a compact structure, particularly due to excessive refractive power in moving lens units leading to increased breathing (variation in angle of view) during focusing.
Innovation Solution
The optical system comprises a first lens unit, a second lens unit with negative refractive power, a third lens unit, and a fourth lens unit with positive refractive power, arranged from the object side to the image side. During focusing, the second lens unit moves toward the image side, and the fourth lens unit moves toward the object side, with specific focal length ratios and movement constraints to reduce aberration variations and angle of view changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the second lens unit has an excessively strong refractive power to enable high-speed focusing, then focusing speed is improved, but breathing (variation in angle of view) increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive power of the second lens unit through the focal length ratio condition (0.1 < |f2/f| < 0.5) and by optimizing the movement distances of the second and fourth lens units during focusing. This balances the need for high-speed focusing with the requirement to minimize breathing effects.
Solution Approach 2:
The patent employs dynamics by making the second and fourth lens units movable during focusing. The second lens unit moves toward the image side while the fourth lens unit moves toward the object side, allowing the system to adapt its configuration dynamically to achieve both fast focusing and stable angle of view.
2Manufacturing precision
If multiple lens units move during focusing to reduce aberration variations, then aberration control is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the focusing function across multiple lens units (second and fourth lens units). Each lens unit contributes to aberration correction through its specific movement, allowing complex aberration control to be achieved by coordinating simpler individual movements rather than moving a single complex assembly.
Solution Approach 2:
The patent uses dynamics by implementing coordinated movement of the second and fourth lens units during focusing. This dynamic adjustment allows the system to maintain optimal aberration correction across different focusing distances while keeping each individual lens unit relatively simple in structure.
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 effectively reduces variations in aberrations and the angle of view during focusing, while also enabling a compact structure by optimizing the movement and refractive powers of the lens units, thus addressing the limitations of existing systems.
Implementation Method 1
a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit having a positive refractive power arranged in that order from an object side to an image side
Data Source
AI summary
An optical system includes a first lens unit, a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit having a positive refractive power arranged in that order from an object side to an image side. Intervals between adjacent ones of the lens units change during focusing. The second lens unit moves toward the image side and the fourth lens unit moves toward the object side during focusing from infinity to close range. A certain inequality is satisfied.