Zoom Lens Compact Design Abbe Number Optimization
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Solution Overview
Problem
Existing zoom lenses face challenges in downsizing while maintaining effective aberration correction over the entire zoom range, particularly in reducing back focus and outer diameter, and in correcting chromatic aberration of magnification at both wide-angle and telephoto ends.
Innovation Solution
The zoom lens configuration includes a first lens unit with a negative lens and multiple positive lenses made of materials with higher Abbe numbers, and a rear lens group with a positive lens unit, where the intervals between lens units are adjusted for zooming, satisfying specific conditional expressions to optimize refractive power and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the refractive power of the first lens unit is increased to reduce back focus and outer diameter, then the zoom lens becomes more compact, but chromatic aberration of magnification at the telephoto end becomes difficult to correct
Solution Approach 1:
The patent applies parameter changes by carefully selecting the Abbe number of the negative lens material within a specific range (15.00 < νd1n < 23.40) to achieve the right balance between refractive power and chromatic aberration correction. This allows increasing the refractive power for compactness while maintaining aberration correction capability through optimized material parameters.
Solution Approach 2:
The patent uses composite material strategy by combining a negative lens with specific Abbe number range and positive lenses with higher Abbe numbers in the first lens unit. This composite configuration enables the system to achieve both high refractive power for compactness and effective chromatic aberration correction through the complementary optical properties of different materials.
2Area of stationary object
If the refractive power of the first lens unit is increased to reduce outer diameter, then the zoom lens becomes more compact, but chromatic aberration of magnification at the telephoto end becomes difficult to correct
Solution Approach 1:
The patent uses parameter changes by optimizing the Abbe number of the negative lens material to a specific range that enables high refractive power for reduced outer diameter while maintaining chromatic aberration correction capability through the material's optical properties.
Solution Approach 2:
The patent employs composite materials by combining the negative lens with specific Abbe number and positive lenses with higher Abbe numbers, creating a first lens unit that achieves both compact outer diameter and effective chromatic aberration correction through the synergistic optical properties of the material combination.
3Power
If only the Abbe number of the negative lens is changed to increase refractive power, then the zoom lens becomes more compact, but chromatic aberration of magnification at the telephoto end becomes difficult to correct
Solution Approach 1:
The patent applies parameter changes not only to the negative lens Abbe number but also to the Abbe numbers of positive lenses in the first lens unit. By coordinating changes in multiple material parameters, the system achieves high refractive power while maintaining chromatic aberration correction capability that would be lost if only the negative lens parameter were changed.
Solution Approach 2:
The patent uses composite materials strategy by optimizing the combination of negative lens material and positive lens materials with higher Abbe numbers. This multi-material approach allows the system to achieve high refractive power for compactness while the complementary dispersion properties of the material组合 enable effective chromatic aberration correction.
4Length of moving object
If the zoom lens is downsized, then the back focus and outer diameter are reduced, but it becomes difficult to correct chromatic aberration of magnification over the entire zoom range
Solution Approach 1:
The patent applies parameter changes across multiple lens units by optimizing the Abbe number of the negative lens in the first lens unit and the Abbe numbers of positive lenses in both the first and fourth lens units. This coordinated parameter optimization enables compact total lens length while maintaining chromatic aberration correction capability across the entire zoom range.
Solution Approach 2:
The patent employs composite materials strategy by distributing material optimization across multiple lens units - using a negative lens with specific Abbe number range in the first lens unit and positive lenses with higher Abbe numbers in the first and fourth lens units. This multi-location material optimization enables the compact zoom lens to correct chromatic aberration of magnification throughout the entire zoom range.
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 results in a compact zoom lens that effectively corrects chromatic aberration of magnification over the entire zoom range, reduces the total lens length, and minimizes the outer diameter, while ensuring sufficient convergence of rays and correction of aberrations at both ends.
Implementation Method 1
a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear lens group including a plurality of lens units and having a positive refractive power as a whole
Implementation Method 2
a plurality of positive lenses, which are arranged on the image side of the negative lens and are made of materials each having an Abbe number that is larger than an Abbe number of a material of the negative lens
Data Source
AI summary
Provided is a zoom lens including a plurality of lens units, which consist of, in order from an object side to an image side: a positive first lens unit; a negative second lens unit; and a rear lens group including a plurality of lens units and having a positive refractive power as a whole, the first lens unit including a negative lens G1n arranged closest to the object side, and a plurality of positive lenses arranged on the image side of the negative lens, and the rear lens group includes a positive lens Grp. A lens unit arranged closest to the image side in the rear lens group includes the positive lens Grp. At this time, an Abbe number of the negative lens G1n, a refractive index of the positive lens Grp, and back focuses at a wide-angle end and a telephoto end, respectively, are appropriately set.