Compact Zoom Lens System with Segmented Groups
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Solution Overview
Problem
Conventional zoom lens systems for small electronic devices are large in size, expensive to manufacture, and have undesirable exit pupil positions, limiting their optical quality and zoom range.
Innovation Solution
A five-element zoom lens system with a first lens group having negative power and a second lens group comprising three elements with specific optical powers, allowing for a compact design and adjustable focal length to achieve a zoom ratio of at least 2.8, while maintaining a desirable exit pupil position and optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional np-type zoom lens systems are used with multiple lens elements (7 or more), then the system can achieve sufficient zoom range, but the system size becomes larger than desired and manufacturing cost increases
Solution Approach 1:
The lens system is divided into two functional groups: a first lens group with negative power (containing 2-3 lens elements) and a second lens group with positive power (containing the remaining elements). This segmentation allows each group to be optimized independently, reducing the total element count while maintaining zoom capability.
Solution Approach 2:
The patent specifies particular parameter ranges for the lens elements, including the ratio of the absolute value of the first principal point of the first sub-group to the effective focal length (0.4-0.75), and specific focal length ratios between lens groups. These parameter optimizations enable compact design while achieving the required zoom range of at least 2.8x.
2Volume of moving object
If the first lens group is reduced to fewer elements for compactness, then the lens system size decreases, but the exit pupil position becomes too close to the image for proper sensor function
Solution Approach 1:
The patent establishes a critical parameter range for the first principal point to effective focal length ratio (0.4-0.75) that simultaneously achieves compact lens system size and proper exit pupil positioning. This parameter optimization ensures the exit pupil is positioned at an appropriate distance from the image plane for sensor functionality.
Solution Approach 2:
The first lens group is designed with specific local optical properties (negative power with controlled principal point position) that differ from conventional designs. This localized optimization of the first group's characteristics enables it to provide both compactness and correct exit pupil positioning without requiring additional elements.
3Ease of manufacture
If the number of lens elements is reduced to five or fewer for cost reduction, then manufacturing expense decreases, but optical quality and image surface flatness may be compromised
Solution Approach 1:
The patent specifies precise parameter ranges for each lens element's optical properties, including focal lengths, principal point positions, and power distributions. These parameter constraints guide the design of a five-element system that maintains adequate optical quality and image surface flatness while minimizing manufacturing cost.
Solution Approach 2:
The patent combines multiple optical functions into fewer lens elements through careful design. The first lens group (negative power) and second lens group (positive power) are configured to work together, with the second group containing a sub-group that provides telephoto effect, thereby achieving sufficient optical performance with only five total elements.
4Volume of moving object
If a compact lens design is implemented with fewer elements, then the system becomes smaller and cheaper, but the zoom ratio capability is reduced below the required 2.8x
Solution Approach 1:
The patent designs the lens system with movable lens groups that change relative positions during zoom operation. The first lens group (negative power) and second lens group (positive power) move independently, with the second group containing a stationary third lens element and a movable first sub-group. This dynamic configuration enables a zoom ratio of at least 2.8x within a compact form factor.
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 system achieves a compact size, sufficient zoom range, and improved optical quality, making it suitable for small electronic cameras while being inexpensive to manufacture, with the ability to maintain a flat image surface and optimal exit pupil position.
Implementation Method 1
A zoom lens system includes a first lens group having a negative power and including two lens elements and a second lens group having a positive power and including three lens elements
Data Source
AI summary
A five-element 3:1 zoom lens system in which the first lens group has a negative power and includes two lens elements and the second lens group has a positive power and includes a pair of lens sub-groups, the first sub-group having a positive power and including a pair of lens elements and the second sub-group having a positive power and including a single lens element. In one embodiment the second sub-group remains stationary relative to the location of the image plane and in another embodiment the second sub-group remains stationary relative to the first sub-group while they are moved relative to the location of the image plane. Several of the lens element surfaces are aspherical. The second lens element of the first sub-group is relatively thick and has a relatively high optical power. The overall length of the lens system is relatively short.