Compact Single Focal Length Lens System with Moving Rear Unit
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Solution Overview
Problem
Existing single focal length lens systems for camera systems are not compact or lightweight, and they lack high-speed and silent focusing capabilities, which are essential for modern camera technology.
Innovation Solution
A single focal length lens system comprising a front lens unit with a negative and positive lens element, fixed in focusing, and a rear lens unit with a focusing and fixed lens unit, where the focusing lens unit moves along the optical axis, satisfying specific focal length and optical axial distance conditions to achieve compactness, light weight, and high-speed focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single focal length lens system is designed to be compact and lightweight, then the size and weight are reduced, but the imaging performance may deteriorate
Solution Approach 1:
The lens system is divided into multiple lens units (first lens unit with negative lens, second lens unit with positive lens, third lens unit with focusing lens, fourth lens unit with fixed lens). This segmentation allows each unit to be optimized for specific functions while achieving overall compactness without sacrificing imaging performance.
Solution Approach 2:
The patent specifies precise parameter relationships including the condition 0.4 < W/fGF < 2.0, where W is the overall length and fGF is the focal length of the focusing lens unit. By controlling these parameters within specific ranges, the system achieves compactness while maintaining excellent imaging characteristics.
2Reliability
If a single focal length lens system uses more lens elements to improve imaging performance, then the imaging quality increases, but the device complexity and size increase
Solution Approach 1:
The lens system is divided into multiple lens units (first lens unit with negative lens, second lens unit with positive lens, third lens unit with focusing lens, fourth lens unit with fixed lens). This segmentation allows each unit to be optimized for specific functions while achieving overall compactness without sacrificing imaging performance.
Solution Approach 2:
The third lens unit includes a focusing lens that can move along the optical axis to achieve focusing from infinity to close objects. This dynamic element provides focusing capability without requiring multiple fixed lens elements, reducing overall system complexity while maintaining imaging performance.
3Speed
If a lens system implements high-speed focusing capability, then the focusing speed increases, but the device complexity and size increase
Solution Approach 1:
The third lens unit includes a focusing lens that can move along the optical axis to achieve focusing from infinity to close objects. This dynamic element provides focusing capability without requiring multiple fixed lens elements, reducing overall system complexity while maintaining imaging performance.
Solution Approach 2:
The patent specifies precise parameter relationships including the condition 0.4 < W/fGF < 2.0, where W is the overall length and fGF is the focal length of the focusing lens unit. By controlling these parameters within specific ranges, the system achieves compactness while maintaining excellent imaging characteristics.
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 solution results in a compact, lightweight lens system with excellent imaging performance, enabling high-speed and silent focusing, suitable for camera systems, while maintaining manufacturing efficiency and reducing size and cost.
Implementation Method 1
a front lens unit which does not move along an optical axis but is fixed in focusing from an infinity in-focus condition to a close-object in-focus condition, and in which a negative lens element having negative optical power is disposed at an object-side most, and a positive lens element having positive optical power is disposed at an image-side side relative to the negative lens element
Implementation Method 2
a rear lens unit which includes a focusing lens unit moving along an optical axis in focusing, and a fixed lens unit not moving along the optical axis but fixed in focusing
Data Source
AI summary
A single focal length lens system comprising a front lens unit, an aperture diaphragm, and a rear lens unit, wherein the front lens unit is composed of three or less lenses including a negative lens located closest to the object side and a positive lens located on the image side relative to the negative lens, and does not move along an axis in focusing, the rear lens unit includes a focusing lens unit moving along the axis and a fixed lens unit not moving along the axis in focusing, and the conditions: 0.4<fW/fGF<1.5, 0.9<fW/T1<4.5, and −0.3<fW/fG1<0.3 (fW, fGF, fG1: focal lengths of the entire single focal length lens system, the focusing lens unit, the front lens unit, T1: an axial distance from an object side lens surface of the negative lens to the aperture diaphragm) are satisfied.