Diffractive Zoom Lens Layout for Compact Aberration Correction
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Solution Overview
Problem
Existing zoom lenses face challenges in reducing thickness and size while effectively correcting chromatic and geometric aberrations, particularly when using diffractive optical elements, and require complex manufacturing or temperature/displacement controls.
Innovation Solution
The zoom lens incorporates dispersion-controlled diffractive surfaces with specific Abbe number ranges and refractive surfaces to correct aberrations, allowing for reduced thickness and size without increasing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diffractive optical elements are used to correct chromatic aberration, then chromatic aberration correction is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Abbe number of the diffractive surface within a specific range (20 ≤ ν0 < 40) and defining exact relationships between optical path difference functions at different wavelengths. This parameter control enables effective chromatic aberration correction while maintaining manufacturability through standardized design criteria.
Solution Approach 2:
The patent employs composite optical structures by combining refractive surfaces with diffractive surfaces in lens units. This composite approach allows the system to leverage both refractive and diffractive optical effects, achieving superior chromatic aberration correction without requiring purely diffractive elements that would be more complex to manufacture.
2Length of moving object
If lens thickness is reduced to make the zoom lens compact, then size is improved, but aberration correction capability deteriorates
Solution Approach 1:
The patent applies local quality by introducing diffractive surfaces with specific dispersion characteristics at strategic locations within the lens units. These localized diffractive elements provide targeted chromatic aberration correction in specific regions of the optical path, enabling compact lens design without sacrificing overall aberration correction capability.
Solution Approach 2:
The patent utilizes parameter changes by controlling the Abbe number of diffractive surfaces and optimizing the optical path difference functions to achieve effective aberration correction in a reduced thickness configuration. The specific parameter ranges and mathematical relationships defined enable compact design while maintaining optical performance.
3Manufacturing precision
If diffractive surfaces with high dispersion control are used, then chromatic aberration correction is improved, but wavelength dispersion control complexity increases
Solution Approach 1:
The patent applies parameter changes by defining specific mathematical relationships for optical path difference functions at multiple wavelengths (d-line, F-line, C-line) and constraining the Abbe number within a precise range. This parameterization transforms complex wavelength dispersion control into manageable design criteria with clear targets and tolerances.
Solution Approach 2:
The patent replaces complex mechanical or computational dispersion control mechanisms with optical design principles based on diffractive surface geometry and material selection. By substituting physical control systems with inherent optical properties of the diffractive surfaces, the solution simplifies the overall system while maintaining precise wavelength dispersion control.
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 corrects chromatic and geometric aberrations, enabling a compact zoom lens design that can be easily retracted into an image pickup apparatus.
Implementation Method 1
at least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion
Implementation Method 2
at least one of the plurality of lens units has a refractive surface
Data Source
AI summary
A zoom lens includes a plurality of lens units. Each distance between adjacent lens units changes during zooming. At least one of the plurality of lens units has a diffractive surface with controlled wavelength dispersion. A predetermined inequality is satisfied.