Compact Zoom Lens with Aperture Stop Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing zoom lenses for surveillance cameras lack compactness and high optical performance, especially in bright environments and near-infrared ranges, with insufficient chromatic aberration correction.
Innovation Solution
A two-unit zoom lens configuration with a negative refractive power first lens unit and a positive refractive power second lens unit, including an aperture stop, where the distance between the units changes during zooming, satisfying specific conditional expressions to achieve compactness and high optical performance across visible and near-infrared wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-unit zoom lens configuration with negative and positive lens units is used, then chromatic aberration correction in the near infrared range is improved, but the overall lens length increases and compactness deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the focal length ratio between the first and second lens units, and by selecting lens materials with specific Abbe numbers. The conditional expressions define precise parameter ranges that enable chromatic aberration correction while limiting the increase in overall lens length, thus resolving the contradiction between optical performance and compactness.
2Reliability
If the aperture stop is placed in the second lens unit, then optical performance in bright environments is improved, but the lens structure complexity increases
Solution Approach 1:
The patent merges the aperture stop with the second lens unit, integrating the light control function directly into the lens structure. This combination improves optical performance in bright environments by precisely controlling light entry while avoiding the need for separate aperture mechanisms, thus managing structural complexity.
3Reliability
If two or more negative lenses are included in the second lens unit, then chromatic aberration correction is improved, but the number of lens elements increases and compactness is reduced
Solution Approach 1:
The patent uses parameter changes by specifying the Abbe number range for the negative lenses in the second unit and defining the relationship between their focal lengths. These controlled parameter variations enable effective chromatic aberration correction with a limited number of elements, preventing excessive increase in lens unit length.
Solution Approach 2:
The patent employs composite material principles by combining negative and positive lens elements with different Abbe numbers in the second lens unit. This composite arrangement of optical materials with complementary properties enables chromatic aberration correction while maintaining a compact lens unit structure.
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 provides a compact zoom lens with a large aperture and high optical performance, effectively correcting chromatic aberrations and enabling imaging in bright environments and near-infrared ranges.
Implementation Method 1
a first lens unit L1 having a negative refractive power and a second lens unit L2 having a positive refractive power in order from an object side to an image side, a distance between the first lens unit and the second lens unit changing during zooming
Implementation Method 2
The second lens unit L2 includes an aperture stop and two or more negative lenses... effectively correcting chromatic aberrations... in a wavelength range from a visible light wavelength to a near infrared light wavelength
Data Source
AI summary
A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power. A distance between the first lens unit and the second lens unit changes during zooming. The second lens unit includes an aperture stop and two or more negative lenses. The zoom lens satisfies specified conditional expressions.