Seven-Lens Zoom Assembly with Moving Groups
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Solution Overview
Problem
Conventional optical lens assemblies face challenges in balancing image quality, sensitivity, aperture size, volume, and field of view, making it difficult to meet the diverse requirements of modern electronic devices with high image quality and efficient zooming capabilities.
Innovation Solution
The image lens assembly comprises seven lens elements, including a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group, where the relative positions of the first and fourth lens groups are fixed, and the second and third lens groups move along the optical axis, allowing for optical zoom with a small field of view and a wide zoom range, using at least four plastic lens elements to achieve compactness and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lens elements is increased to improve image quality, then image quality is improved, but device complexity and volume increase
Solution Approach 1:
The lens assembly is divided into four distinct lens groups (first, second, third, and fourth lens groups), each with specific functions. This segmentation allows complex optical functions to be distributed across multiple simpler groups, improving image quality while managing overall complexity through modular design
Solution Approach 2:
The lens groups serve multiple functions: the first and second lens groups work together for focusing, the third lens group contributes to both focusing and zooming, and the fourth lens group handles both operations. This multi-functionality reduces the need for additional dedicated components, balancing image quality with device complexity
2Illumination intensity
If the aperture size is increased to improve sensitivity, then sensitivity is improved, but volume and device size increase
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (first, second, third, fourth, fifth, and sixth lens elements) to optimize light gathering efficiency. This allows the system to achieve high sensitivity with a more compact aperture design by improving light distribution and reducing optical losses
Solution Approach 2:
Aspheric surfaces are used on multiple lens elements to optimize light path and improve sensitivity. The curved aspheric surfaces efficiently gather and direct light to the image sensor, achieving high sensitivity without requiring a larger aperture diameter that would increase volume
3Area of stationary object
If the field of view is increased to improve coverage, then coverage is improved, but manufacturing precision and image quality control become more difficult
Solution Approach 1:
Different lens groups are assigned specific optimization goals: the first and second lens groups focus on central field image quality, while the third and fourth lens groups are optimized for wide-angle performance and distortion control. This local optimization allows the system to achieve wide field of view coverage while maintaining image quality across different field regions
Solution Approach 2:
The lens groups are designed to move relative to each other during focusing and zooming operations. This dynamic adjustment allows the optical system to maintain image quality across a wide field of view by compensating for aberrations that occur at different field angles and focus distances
4Ease of manufacture
If plastic material is used to reduce cost and manufacturing complexity, then manufacturing cost is reduced, but image quality and precision may deteriorate
Solution Approach 1:
The patent specifies precise refractive index ranges for plastic lens elements (1.50-1.70 for most elements, 1.80-2.00 for the seventh element) and incorporates aspheric surfaces to compensate for material limitations. These parameter optimizations allow plastic materials to achieve image quality comparable to glass while maintaining cost and manufacturing advantages
Solution Approach 2:
The lens assembly uses a composite approach by primarily using plastic materials for most lens elements (first through sixth elements) while potentially using glass for the seventh element or specific critical elements. This composite material strategy balances manufacturing cost with image quality requirements
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
This configuration enables a wider zoom range while maintaining high image quality, balancing zoom efficiency and image quality, and reducing manufacturing complexity and costs by using plastic materials and optimizing lens element positions and refractive powers.
Implementation Method 1
The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof, and the second lens element has negative refractive power
Data Source
AI summary
An image lens assembly includes, in order from an object side to an image side along an optical path, a first lens group, a second lens group, a third lens group and a fourth lens group. A total number of lens elements in the image lens assembly is seven. The first lens group includes a first lens element with positive refractive power and a second lens element with negative refractive power. Each of the second lens group and the third lens group includes at least one lens element. The fourth lens group includes a seventh lens element. When the image lens assembly is focusing or zooming, a relative position between the first lens group and an image surface is fixed, a relative position between the fourth lens group and the image surface is fixed, and the second lens group and the third lens group move along the optical axis.