Four-Group Zoom Lens for Continuous Mobile Optical Zoom
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Solution Overview
Problem
Current mobile phone lenses with jumping digital zoom suffer from discontinuous imaging quality due to multiple lenses with different focal lengths, leading to lower definition in zoom transitions, which cannot meet consumer demands for continuous optical zoom with high resolution and imaging quality.
Innovation Solution
A zoom lens design comprising four lens groups, including a fixed first group, a movable second group with negative focal power, a movable third group with positive focal power, and a fixed fourth group, allowing continuous zooming by opposing movements of the second and third groups, with optimized focal power and track length ratios to enhance imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple lenses with different focal lengths are installed to achieve jumping digital zoom, then zoom range is improved, but imaging quality deteriorates due to discontinuous definition in zoom transitions
Solution Approach 1:
The patent employs a dynamic lens group configuration where the second lens group (with negative focal power) and third lens group (with positive focal power) can move independently along the optical axis. This dynamic adjustment enables continuous focal length variation without discrete lens switching, achieving smooth optical zoom transitions that maintain continuous imaging definition throughout the zoom range.
Solution Approach 2:
The zoom lens is divided into four distinct lens groups with specific focal powers: first lens group (positive, fixed), second lens group (negative, movable), third lens group (positive, movable), and fourth lens group (positive, fixed). This segmentation allows independent optimization of each group's function while enabling continuous zoom through coordinated movement of the movable groups.
2Adaptability or versatility
If two or three lenses with different focal lengths are installed for hybrid optical zoom, then zoom capability is improved, but device complexity increases
Solution Approach 1:
The fourth lens group serves multiple functions simultaneously: it acts as a fixed positive lens group that compresses beam angle during zooming, matches the chief ray angle of the image sensor, and corrects field curvature and aberrations. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall device complexity while maintaining zoom capability.
3Manufacturing precision
If continuous zooming is implemented with movable lens groups, then imaging quality is improved, but motor stroke requirements increase
Solution Approach 1:
The second lens group (with negative focal power) and third lens group (with positive focal power) are positioned and configured to move in opposite directions along the optical axis during zooming. This counterbalancing arrangement allows the lens groups to compensate for each other's movement, reducing the total stroke length required for the motors while maintaining continuous zoom functionality.
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 design achieves continuous zooming with improved imaging quality, reduced motor design complexity, and miniaturization, while maintaining high resolution and flexibility in lens placement, suitable for mobile terminals.
Implementation Method 1
The second lens group is a zoom lens group with negative focal power. The third lens group is a compensative lens group with positive focal power. Both the second lens group and the third lens group can move along an optical axis of the zoom lens
Implementation Method 2
The first lens group is a fixed lens group with positive focal power. The first lens group is capable of converging rays to compress beam apertures of the second lens group and the third lens group
Implementation Method 3
The fourth lens group is a fixed lens group with positive focal power. The fourth lens group is configured to compress a beam angle during zooming, so that a chief ray angle of the zoom lens matches a chief ray angle of the image sensor
Data Source
AI summary
Embodiments of this application disclose a zoom lens, a camera module, and a mobile terminal. The zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group that are arranged along an object side to an image side. The first lens group is a fixed lens group with positive focal power, the second lens group is a zoom lens group with negative focal power, the third lens group is a compensative lens group with positive focal power, and the fourth lens group is a fixed lens group with positive focal power. In a zooming process of the zoom lens from a short-focal end to a long-focal end, the second lens group moves towards the image side along an optical axis, and the third lens group moves towards the object side along the optical axis.