Zoom Lens Compact Design via Refractive Index Optimization
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Solution Overview
Problem
Existing zoom lenses face challenges in achieving a wide angle of view of 38 degrees or more, a changing magnification rate of 6.5 or more, and a resolving power equivalent to 5 to 8 million pixels, while minimizing the maximum total lens length and thickness of each lens group, due to complex configurations and increased size.
Innovation Solution
A zoom lens configuration with a first lens group having positive refracting power, a second lens group with negative refracting power, and a third lens group with positive refracting power, where the first and third lens groups move towards the object side to increase spacing between the first and second lens groups and decrease spacing between the second and third lens groups, utilizing high refractive index materials in the second lens group to thin the lens groups and correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to achieve high resolving power and wide angle of view, then the optical performance is improved, but the total lens length and device size increase
Solution Approach 1:
The patent applies parameter changes by selecting specific refractive index ranges for lenses in the second lens group (average Nd2G ≥ 1.90). This material parameter optimization enables high resolving power equivalent to 5-8 million pixel imaging elements while maintaining a compact total lens length suitable for mobile devices.
2Adaptability or versatility
If the number of lenses is increased to achieve wide angle of view and high magnification rate, then the optical performance is improved, but the device complexity increases
Solution Approach 1:
The patent optimizes the refractive index parameters of lenses in the second lens group to achieve a wide half angle of view of 38 degrees or more and a high changing magnification rate of 6.5 or more. This parameter-based approach avoids the need for complex multi-element lens configurations, thereby reducing device complexity while maintaining versatile optical performance.
3Measurement precision
If the thickness of each lens group is increased to reduce aberrations, then the optical quality is improved, but the total length in storage increases
Solution Approach 1:
The patent achieves effective aberration correction by optimizing the refractive index parameters of lenses in the second lens group (average Nd2G ≥ 1.90) rather than increasing lens group thickness. This enables high optical quality while maintaining a compact form factor with reduced total length in storage.
4Length of stationary object
If high refractive index materials are used to thin the lens groups, then the lens group thickness is reduced, but the manufacturing difficulty increases
Solution Approach 1:
The patent specifies a practical refractive index range (average Nd2G ≥ 1.90) for lenses in the second lens group that balances thinning the lens groups with manufacturing feasibility. This parameter optimization reduces lens group thickness while avoiding excessively high refractive index materials that would pose significant manufacturing challenges.
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 solution effectively reduces the maximum total lens length and thickness of each lens group, achieving the desired wide angle view, high magnification rate, and resolving power, while maintaining a compact size and correcting aberrations efficiently.
Implementation Method 1
a second lens group having a negative refracting power... an average Nd2G of refractive indexes in d-lines of all lenses in the second lens group satisfies the following condition: 1.90 ≤ Nd2G
Data Source
AI summary
The invention provides a zoom lens including at least a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, in order from an object side, and an aperture stop between the second lens group and the third lens group, wherein, in changing magnification from a wide angle end toward a telephoto end, at least the first lens group and the third lens group move toward the object side so as to increase a spacing between the first lens group and the second lens group, and to decrease a spacing between the second lens group and the third lens group.