Zoom Lens Tolerance Reduction via Aspheric Extraction
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Solution Overview
Problem
Conventional zoom lenses face challenges in reducing manufacturing costs and improving yield due to high tolerance accumulation and the use of aspheric molding glass lenses with high refractive index, which complicates mass production and increases costs.
Innovation Solution
A zoom lens design with four lens groups, including a first, second, third, and fourth lens group, where the third lens group is reduced to two lenses with positive refractive power, and the fourth lens group moves to adjust magnification and image compensation, utilizing aspheric, glass molding, or plastic lenses to minimize tolerance accumulation and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aspheric molding glass lenses with high refractive index are used in the third lens group, then image aberration is corrected, but tolerance accumulation increases and manufacturing yield decreases
Solution Approach 1:
The patent extracts the aspheric lens from the third lens group and relocates it to the fourth lens group. This separation allows the third lens group to use only spherical lenses with lower refractive indices, reducing tolerance accumulation and improving manufacturing yield, while the aspheric lens in the fourth group continues to correct image aberration effectively.
Solution Approach 2:
The patent changes the refractive index parameters of lenses in the third lens group by replacing high refractive index spherical lenses with lower refractive index materials. This parameter change reduces the sensitivity to manufacturing tolerances and improves overall production yield while maintaining optical performance through the aspheric lens in the fourth group.
2Manufacturing precision
If multiple spherical lenses with high refractive index are fitted with aspheric molding glass lens in the third lens group, then image quality is improved, but manufacturing cost increases due to high tolerance accumulation
Solution Approach 1:
The aspheric molding glass lens is extracted from the third lens group and placed in the fourth lens group. This reduces the number of aspheric lenses in the third group from one to zero, significantly lowering tolerance accumulation requirements and manufacturing costs, while the extracted aspheric lens in the fourth group maintains image quality correction.
Solution Approach 2:
The patent replaces expensive aspheric molding glass lenses in the third lens group with cheaper spherical lenses made from materials with lower refractive indices. These spherical lenses are easier and cheaper to manufacture with standard tolerances, reducing overall manufacturing cost while the single aspheric lens in the fourth group provides necessary aberration correction.
3Reliability
If the third lens group comprises one aspheric lens and two spherical lenses, then optical performance is maintained, but it is difficult to improve overall yield in mass production
Solution Approach 1:
The aspheric lens is extracted from the third lens group configuration and relocated to the fourth lens group. This changes the third lens group composition to exclusively spherical lenses, which are much easier to manufacture in mass production with consistent quality, thereby improving overall yield while the aspheric lens in the fourth group preserves optical performance.
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 reduces material and manufacturing costs, improves yield, and maintains high optical quality by reducing the number of lenses, eliminating image aberration, and providing image compensation, while maintaining effective focal length and incidence angle specifications.
Implementation Method 1
At least one of the seventh and eighth lenses is an aspheric lens. The seventh and the eighth lenses have the positive refractive power.
Implementation Method 2
The aspheric lens is, for example, a glass molding lens, a hybrid lens, or a plastic lens.
Data Source
AI summary
A zoom lens suitable for imaging an object on a photosensitive element is provided. The zoom lens includes a first lens group, a second lens group disposed between the first lens group and the photosensitive element, a third lens group disposed between the second lens group and the photosensitive element, and a fourth lens group. The second lens group is suitable for moving between the first lens group and the third lens group. The third lens group includes two lenses having positive refractive power. The fourth lens group is disposed and suitable for moving between the third lens group and the photosensitive element. The refractive powers of the first lens group, the second lens group, the third lens group, and the fourth lens group are a positive value, a negative value, a positive value, and a positive value respectively.