Compact Wide Angle Lens Design for Telecentricity and Aberration Correction
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Solution Overview
Problem
Conventional small-size wide angle lenses for digital cameras face challenges in achieving a compact size while maintaining a small F-number and wide angle with high performance, as they often require a collapsible mount method that increases camera size and power consumption, and struggle with telecentricity and aberration correction.
Innovation Solution
A small-size wide angle lens design comprising a first lens group with positive refractive power, a stop, and a third lens group with negative refractive power, arranged in a specific order, including aspheric surfaces and cemented lenses, which satisfies specific formulas to optimize focal length, aperture position, and refractive indices for improved telecentricity and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stop is located at a distant position away from the imaging device to achieve rays perpendicular to the image plane, then telecentricity is improved, but the distance from the most-object-side surface to the imaging device becomes long, increasing camera size
Solution Approach 1:
The lens system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and third lens group with positive refractive power) with the stop positioned between the first and second lens groups. This segmentation allows the stop to be located at an intermediate position rather than at the distant image side, achieving telecentricity while maintaining a compact overall length.
Solution Approach 2:
The patent changes the positional dimension of the stop from the traditional distant image-side position to an intermediate object-side position between lens groups. This dimensional repositioning enables the stop to control ray angles effectively while being located closer to the object side, thus reducing the overall distance from the most-object-side surface to the imaging device.
2Volume of moving object
If a collapsible mount method is used to reduce camera size, then the camera size in carried state is reduced, but time is needed to slide the lens out and operations consume battery power
Solution Approach 1:
The lens system is designed to be self-contained and functional in a fixed mount configuration. The optical design with three lens groups and strategically positioned stop achieves compact size and high performance without requiring external mechanical collapse mechanisms, making the lens system self-sufficient and eliminating the need for power-consuming slide operations.
Solution Approach 2:
The patent extracts the collapsible mount mechanism entirely from the system, replacing it with a fixed-mount lens design that achieves compactness through optical arrangement rather than mechanical transformation. This removes the harmful factor of requiring slide operations while maintaining small size.
3Reliability
If the number of lens groups is increased to improve aberration correction, then optical performance is improved, but the device complexity and size increase
Solution Approach 1:
Each lens group is designed with specific local optical properties: the first lens group has positive refractive power, the second has negative refractive power, and the third has positive refractive power. The stop is positioned locally between the first and second groups. This localized optimization of refractive power distribution and stop positioning enables effective aberration correction with only three lens groups, avoiding unnecessary complexity.
Solution Approach 2:
The patent optimizes specific parameters including the refractive powers of each lens group, the position of the stop between groups, and the focal length relationships. By carefully controlling these parameters, the system achieves high aberration correction performance with a minimal number of lens groups, balancing performance and complexity.
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 a compact lens system with excellent telecentricity, reduced size, and high performance, enabling a wide angle view without the need for a collapsible mount, while maintaining a small F-number and effectively correcting aberrations.
Implementation Method 1
at least one of the second lens group and the third lens group includes an aspheric surface
Implementation Method 2
excellent telecentricity, and the size of which is reduced, while maintaining a small F-number, a wide angle and high performance
Implementation Method 3
including aspheric surfaces and cemented lenses, which satisfies specific formulas to optimize focal length, aperture position, and refractive indices
Implementation Method 4
a first lens group having positive refractive power, a stop, and a third lens group with negative refractive power
Data Source
AI summary
A small-size wide angle lens substantially consists of a first lens group having positive refractive power, a stop, a second lens group having positive refractive power, and a third lens group having negative refractive power, which are arranged in this order from the object side. Each of the first lens group, the second lens group and the third lens group includes a negative lens and a positive lens. Further, at least one of the second lens group and the third lens group includes an aspheric surface. Further, the small-size wide angle lens satisfies predetermined formulas.