Zoom Lens Configuration for Compact High-Resolution Imaging
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving high optical performance with a wide angle of view and high zoom ratio while maintaining a small overall size, which is essential for surveillance cameras and other image pickup systems, as they tend to increase in size and weight when trying to support higher resolutions like 4K, leading to difficulties in correcting aberrations and requiring larger motors for lens movement.
Innovation Solution
A zoom lens configuration with a first lens unit having negative refractive power, a second lens unit with positive refractive power, and a rear lens group including both negative and positive refractive power units, where the first lens unit does not move during zooming, and the second and positive refractive power units move to adjust the distance between lens units, adhering to specific conditional expressions to optimize focal lengths and movement ratios, thereby maintaining a small size and high zoom ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels of the image pickup element is quadrupled to achieve 4K resolution, then the resolution is improved, but the pixel size is reduced to a quarter of its original size, which decreases the optical performance in low light conditions
Solution Approach 1:
The patent changes the optical parameters of the lens system, specifically the focal lengths and refractive powers of different lens units, to optimize the balance between resolution and low-light performance. By carefully designing the ratio between the focal length of the first lens unit and the absolute value of the focal length of the second lens unit, the system achieves high resolution while maintaining adequate pixel size for low-light conditions
2Measurement precision
If the diagonal length of the image pickup element is doubled to quadruple the number of pixels while maintaining pixel size, then the resolution is improved, but the size and weight of the lens system increase
Solution Approach 1:
The patent divides the lens system into multiple lens units with different functions: a first lens unit with negative refractive power for wide-angle correction, a second lens unit with positive refractive power for zooming, and a rear lens group for focus and aberration control. This segmentation allows each unit to be optimized independently, achieving high resolution without proportionally increasing overall lens size and weight
3Adaptability or versatility
If a wide angle of view is achieved by increasing the effective diameter of the front lens, then the angle of view is improved, but the overall size of the zoom lens increases
Solution Approach 1:
The patent employs an asymmetric lens configuration where the first lens unit has negative refractive power and is specifically designed to correct wide-angle aberrations. This asymmetric design allows the system to achieve a wide angle of view without requiring a proportional increase in the effective diameter of the front lens, thereby controlling the overall lens size
4Adaptability or versatility
If a high zoom ratio is achieved by adjusting the movement amounts of lens units, then the zoom ratio is improved, but the complexity of lens configuration and aberration correction increases
Solution Approach 1:
The patent implements a dynamic zoom mechanism where the second lens unit with positive refractive power moves during zooming to change the focal length. The movement amount of this lens unit is carefully controlled relative to the focal lengths of other units, enabling high zoom ratio while maintaining manageable configuration complexity through defined movement relationships
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 allows for favorable optical performance over the entire zoom range with a small overall size, wide angle of view, and high zoom ratio, effectively reducing the size and weight of the lens system while improving aberration correction and motor requirements.
Implementation Method 1
a first lens unit having a negative refractive power
Implementation Method 2
a second lens unit having a positive refractive power
Implementation Method 3
a rear lens group having a positive refractive power
Data Source
AI summary
The zoom lens according to the present invention includes, in order from an object side to an image side, a negative first lens unit, an aperture stop, a positive second lens unit, and a positive rear lens group. The rear lens group includes a negative lens unit LN and a positive lens unit LP. During zooming, the first lens unit does not move, the second lens unit moves so as to be closer to object side at a telephoto end (TE) than at a wide-angle end (WE), the lens unit LP moves so as to be closer to image side at TE than at WE, and an interval between every adjacent two of lens units changes. Focal lengths of second lens unit and lens unit LP, and an amount by which each of second lens unit and lens unit LP moves for zooming from WE to TE are appropriately set.