Zoom Lens System with Variable Interval Control for Compact High-Magnification Imaging
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Solution Overview
Problem
Conventional zoom lens systems for compact digital cameras face challenges in achieving a high variable magnification ratio of approximately 5 while maintaining a reduced overall optical length and a wide-angle view of 70°, as existing designs either compromise on magnification or increase the overall optical length due to large movement of lens units during zooming.
Innovation Solution
A zoom lens system comprising a first lens unit with negative optical power, a second lens unit with positive optical power, and a third lens unit with positive optical power, where the intervals between these units are adjusted along the optical axis to decrease the interval between the first and second lens units and increase the interval between the second and third lens units during zooming, satisfying conditions such as 1.5 < LT/(Ir×Z) < 2.6 and fT/fW > 4.0, to achieve the desired optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lens units are moved to achieve high variable magnification ratio, then magnification ratio is improved, but overall optical length increases
Solution Approach 1:
The patent applies dynamics by making the intervals between lens units variable rather than fixed. The first lens unit moves relative to the second lens unit along the optical axis during zooming, dynamically adjusting the interval to achieve magnification change while maintaining compact overall length. This dynamic adjustment allows the system to achieve high variable magnification ratio without proportionally increasing the overall optical length.
2Adaptability or versatility
If lens units are moved to achieve variable magnification, then magnification ratio is improved, but view angle at wide-angle limit decreases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the movement parameters of lens units. Specifically, the first lens unit is moved along the optical axis by a precisely calculated amount, and the intervals between lens units are adjusted according to specific relationships involving focal lengths and image heights. This parameter control enables the system to achieve high variable magnification ratio while maintaining a wide-angle view of 70° or more at the wide-angle limit.
3Length of stationary object
If overall optical length is reduced for compact camera, then camera thickness is improved, but achieving high variable magnification ratio becomes difficult
Solution Approach 1:
The patent applies segmentation by dividing the lens system into multiple discrete lens units (first lens unit, second lens unit, and third lens unit) with specific optical powers. Each unit can move independently along the optical axis, allowing the system to achieve high variable magnification ratio (approximately 5) while maintaining a reduced overall optical length suitable for compact cameras.
4Adaptability or versatility
If lens units are moved to achieve zooming, then magnification ratio is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies feedback by establishing specific mathematical relationships between the movement of lens units and the resulting optical parameters. The interval between the first and second lens units is controlled based on relationships involving the focal length of the first lens unit, the focal length of the second lens unit, and the image height. This feedback mechanism ensures that manufacturing precision requirements are managed through well-defined optical constraints rather than arbitrary dimensional tolerances.
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 zoom lens system with high resolution, reduced overall optical length, and a variable magnification ratio of approximately 5, suitable for wide-angle image taking, while maintaining a compact camera design.
Implementation Method 1
a first lens unit having negative optical power, a second lens unit having positive optical power and a third lens unit having positive optical power
Data Source
AI summary
A zoom lens system of the present invention has a plurality of lens units each composed of at least one lens element and, in order from the object side to the image side, comprises: a first lens unit having negative optical power and composed of two lens elements; a second lens unit having positive optical power; and a third lens unit having positive optical power, wherein in zooming, the lens units are moved such that an interval between the first lens unit and the second lens unit should decrease and that an interval between the second lens unit and the third lens unit should increase, so that magnification change is achieved, and wherein the condition is satisfied: 1.5<LT/(Ir×Z)<2.6 where, Z=fT/fW>4.0, ωW>35, Ir: a maximum image height (Ir=fT×tan(ωT)), LT: an overall length at a telephoto limit (a distance from the most object side of the first lens unit to the image surface), fT, fW: focal lengths of the entire system at a telephoto limit, a wide-angle limit, ωW, ωT: half values of maximum view angles at a wide-angle limit, a telephoto limit.