Inner Focus Lens System Compact Design
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Solution Overview
Problem
Existing inner focus lens systems face challenges in achieving a compact size while maintaining high resolution and suppressing aberrations, and they often struggle with image blur compensation.
Innovation Solution
The proposed inner focus lens system consists of a first lens unit fixed with respect to the image surface, followed by focusing lens units that move along the optical axis, and an image blur compensating lens unit that moves perpendicular to the optical axis, satisfying conditions such as LA/fA < 1.2 to ensure compactness and high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the lens system uses a conventional focusing mechanism with multiple lens elements in focusing units, then the focusing function is achieved, but the lens system size increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts the focusing function from the first lens unit and places it in subsequent lens units. Specifically, the first lens unit is fixed with respect to the image surface, while second and third lens units are configured to move along the optical axis for focusing. This separation allows the first lens unit to be optimized for compactness while the focusing units handle the moving components, thereby reducing overall system size and simplifying the focusing mechanism.
Solution Approach 2:
The lens system is segmented into distinct functional units: a first lens unit for fixed positioning, and second and third lens units for focusing movement. This segmentation allows each unit to be optimized independently - the first unit for compactness and the subsequent units for focusing functionality - resolving the contradiction between size and complexity.
2Reliability
If the lens system adds an image blur compensating lens unit that moves perpendicular to the optical axis, then image blur compensation is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the image blur compensation function with the existing focusing lens units. The second lens unit performs dual functions: focusing along the optical axis and image blur compensation by moving perpendicular to the optical axis. This integration eliminates the need for a separate compensating unit, thereby achieving image blur compensation while simplifying the overall structure and easing manufacturing.
3Length of moving object
If the lens system uses a compact configuration with limited lens elements, then the lens system size is reduced, but the ability to suppress various aberrations deteriorates
Solution Approach 1:
The patent applies local quality by giving each lens unit specific optical power characteristics optimized for its function. The first lens unit has positive optical power and is fixed, the second lens unit has negative optical power and handles focusing, while the third lens unit has positive optical power and corrects residual aberrations. This localized optimization of optical properties allows effective aberration suppression within a compact configuration.
Solution Approach 2:
The patent carefully controls the optical parameters of each lens unit, including optical powers, focal lengths, and movement distances. By optimizing these parameters - such as setting specific ranges for the optical powers of the first, second, and third lens units, and controlling the movement distance ratios - the system achieves effective aberration suppression while maintaining a compact 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 results in a compact inner focus lens system with excellent performance, effectively suppressing aberrations and providing high-resolution imaging while reducing image blur caused by hand blurring or vibration.
Implementation Method 1
a first positive lens element being located closest to the object side, and having positive optical power; and a second positive lens element having positive optical power
Implementation Method 2
subsequent lens units include only a first focusing lens unit located closest to the object side, and a second focusing lens unit, as focusing lens units that move along an optical axis in the focusing
Implementation Method 3
the subsequent lens units include an image blur compensating lens unit that moves in a direction perpendicular to the optical axis to optically compensate image blur
Data Source
AI summary
An inner focus lens system comprising a first lens unit and subsequent lens units, wherein the first lens unit: is fixed with respect to an image surface in focusing; and includes a first positive lens element located closest to the object side and a second positive lens element, the subsequent lens units include only a first focusing lens unit located closest to the object side and a second focusing lens unit, at least one of the first focusing lens unit and the second focusing lens unit is composed of two or less lens elements, and the subsequent lens units include an image blur compensating lens unit.