Adhesion Multiple-Layer Diffractive Optical Element for Chromatic Aberration Correction
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Solution Overview
Problem
Small camera shooting lenses, such as those in mobile phones, face issues with chromatic aberration correction and flare due to unnecessary diffraction lights generated by diffraction gratings, leading to haze in images.
Innovation Solution
A shooting lens design incorporating at least three lens groups with an adhesion multiple-layer diffractive optical element on one surface, satisfying specific conditional expressions for dimensions, thickness, and diffraction efficiency to reduce chromatic aberration and flare, while allowing for mass production and high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a diffraction grating is used to correct chromatic aberration, then chromatic aberration is favorably corrected, but unnecessary diffraction lights are generated causing flare and haze in images
Solution Approach 1:
The patent applies local quality by creating different regions on the diffractive optical element with different grating pitches. The first region has a first grating pitch and the second region has a second grating pitch, allowing different parts of the element to handle different aspects of chromatic aberration correction while controlling flare generation in specific areas
Solution Approach 2:
The diffractive optical element is segmented into multiple regions with different grating pitches. This segmentation allows the element to provide differentiated optical functions across different zones, correcting chromatic aberration effectively while minimizing unnecessary diffraction lights that cause flare
2Device complexity
If the number of lenses is reduced to three or four, then device complexity is reduced, but optical performance deteriorates
Solution Approach 1:
The diffractive optical element performs multiple functions simultaneously: it corrects chromatic aberration, controls flare, and works with the lens groups to achieve proper focusing. This multi-functionality allows the system to maintain high optical performance with fewer lenses by having the DOE handle multiple optical corrections that would otherwise require additional lens elements
Solution Approach 2:
The patent uses a composite structure combining lens groups with a diffractive optical element. This composite approach integrates refractive and diffractive optical functions into a single system, achieving complex optical performance correction without requiring a proportional increase in the number of separate lens components
3Ease of manufacture
If a single-layer diffractive optical element is used, then manufacturing is simpler, but optical performance and control over diffraction lights is insufficient
Solution Approach 1:
The diffractive optical element is divided into multiple layers, each with its own grating structure. The first diffractive layer and second diffractive layer can be independently designed and manufactured, then assembled together. This segmentation allows for better control over diffraction characteristics and optical performance while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
The patent transitions from a single-layer to a multi-layer diffractive optical element, adding the dimension of layering. This additional dimension provides extra degrees of freedom for optimizing optical performance, controlling flare, and managing chromatic aberration while keeping each individual layer manufacturable
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 achieves high optical performance and reduces flare, enabling small camera lenses suitable for mass production with improved imaging quality and reduced distortion.
Implementation Method 1
a diffractive optical element with a diffractive optical surface having a grating structure
Implementation Method 2
at least three lens groups disposed in order from an object side
Data Source
AI summary
A small shooting lens has high optical performance and is suitable for mass production. To attain this, the shooting lens includes at least three lens groups disposed in order from an object side, wherein an adhesion multiple-layer diffractive optical element is formed on one of surfaces disposed between an object surface and an imaging plane, and a maximum image height Y and an entire length L satisfy 0.1<Y/L<3.0 . . . (1). Thus using the multiple-layer diffractive optical element in the shooting lens makes it possible to improve diffraction efficiency over a wide range and reduce flare. Particularly, the multiple-layer diffractive optical element has a merit that its production and assembling are easy. Further, according to the conditional expression (1), it is possible to realize the downsizing of the shooting lens while also maintaining its imaging quality.