Compact Zoom Lens System with Fixed Groups
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Solution Overview
Problem
Existing zoom lens systems are too large and inefficient in achieving miniaturization while maintaining changeable magnification, particularly in digital camera applications, due to the size and complexity of the optical system.
Innovation Solution
A zoom lens system with a configuration of a first lens group having negative power, a second lens group having negative power, a third lens group with three single lenses of positive, negative, and negative optical power respectively, and a fourth lens group with positive power, where the first and fourth lens groups remain fixed during zooming, and the third lens group includes an aperture diaphragm and a light amount adjusting device to optimize air space distances and power ratios for miniaturization and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a zoom lens system uses a conventional configuration with multiple lens groups to achieve changeable magnification, then the magnification capability is improved, but the overall size of the optical system increases
Solution Approach 1:
The zoom lens system is divided into four distinct lens groups (Gr1, Gr2, Gr3, Gr4) with specific optical powers, where each group serves a particular function in the zooming mechanism. This segmentation allows independent movement of specific groups (Gr2 and Gr3) while keeping others fixed, enabling magnification change without proportionally increasing the entire system size
Solution Approach 2:
The system employs dynamic movement of the second and third lens groups during zooming operations. By making specific lens groups movable rather than fixed, the system achieves variable magnification (3x zoom ratio) while maintaining a compact overall structure, as only the necessary components move to change focal length
2Reliability
If the third lens group uses a complex multi-element structure to correct aberrations, then the optical performance is improved, but the device complexity increases
Solution Approach 1:
The third lens group (Gr3) is designed with three specific lenses having defined optical powers (positive, negative, negative) arranged in a particular sequence. This localized optimization of the third group's internal structure provides effective aberration correction while keeping the overall system compact, as the correction function is concentrated in this specific region rather than distributed throughout the entire system
Solution Approach 2:
The system satisfies specific conditional expressions regarding focal lengths and air space distances (e.g., 0.43/fw < L3/fw < 1.2, where L3 is the air space between third-second and third-third lenses). By controlling these parameters within defined ranges, the patent achieves effective aberration correction and miniaturization simultaneously, optimizing the balance between performance and compactness
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 enables a compact, high-performance zoom lens system with changeable magnification of about three times, achieving a small size and effective aberration correction, suitable for digital devices like cameras, while maintaining a maximum overall length of 30 mm or less.
Implementation Method 1
a first lens group having a negative optical power, a second lens group having a negative optical power, a third lens group having a positive optical power, and a fourth lens group having a positive optical power which are arranged in this order from an object side
Data Source
AI summary
A zoom lens system includes, in order from an object side: a first lens group having negative power, a second lens group having negative power, a third lens group having positive power, and, a fourth lens group having positive power. The position of the first lens group is fixed during zooming, and the third lens group includes three single lenses including, in order from the object side, a third-first single lens having positive power, a third-second single lens having negative power and a third-third single lens having negative power. The zoom lens system satisfies the following conditional expression: <?in-line-formulae description="In-line Formulae" end="lead"?>0.4<L3/fw<1.2<?in-line-formulae description="In-line Formulae" end="tail"?> where L3 represents the axial air gap distance between the third-second lens and the third-third lens and fw represents the focal length of the entire system of the zoom lens system at a wide angle end position.