Lens Module with Aspheric Groups for Low Distortion
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Solution Overview
Problem
Existing lens modules face challenges in achieving high image quality with low distortion aberration, high definition, high contrast ratio, and high luminance uniformity while maintaining a large field of view and miniaturization, as these requirements often conflict, leading to increased size and fabrication costs.
Innovation Solution
A lens module design comprising a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power, along with an aperture stop, where the first and second lens groups function as a focusing group, and the third group is fixed, optimizing refractive powers and lens configurations to reduce the number and length of lenses, including the use of aspheric lenses to minimize size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large field of view is designed to project large image or capture wide-angle image, then the field of view is improved, but distortion aberration is heightened
Solution Approach 1:
The lens module is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and third lens group with positive refractive power), each contributing to different aspects of aberration correction and field of view expansion, allowing the system to achieve wide angle with controlled distortion
Solution Approach 2:
The patent employs aspheric lenses with specifically designed surface curvatures and refractive indices to correct distortion aberration while maintaining large field of view. The aspheric surfaces allow for precise control of light rays across the entire field, reducing distortion without requiring additional lens elements
2Manufacturing precision
If a considerable number of lenses are used to reduce distortion aberration, then distortion aberration is reduced, but the entire length and size of lens module increase
Solution Approach 1:
Multiple lens groups are combined in a compact arrangement where the first, second, and third lens groups work together to correct aberrations. The merging of these groups with complementary positive and negative refractive powers allows for effective distortion correction within a shortened overall length
Solution Approach 2:
The patent uses aspheric lenses with optimized refractive indices and dispersion characteristics to achieve high aberration correction efficiency. These composite optical elements provide multiple correction functions within single lens components, reducing the total number of elements needed
3Device complexity
If lenses with comparatively large refractive power are used to reduce size and number of lenses, then the size and number of lenses are reduced, but aberration increases to deteriorate image quality
Solution Approach 1:
The patent applies aspheric surfaces specifically to lens elements where they are most effective for aberration correction. By concentrating aspheric design in critical positions within the lens groups, the system achieves high image quality with fewer total lens elements
Solution Approach 2:
The use of aspheric lenses with precisely controlled surface parameters and refractive indices allows each lens element to contribute more effectively to aberration correction. This enables the system to maintain low aberration levels with a reduced number of lenses
4Manufacturing precision
If a main light beam near the reduced side is made to propagate in a direction substantially parallel to the optical axis to enhance luminance uniformity, then luminance uniformity is improved, but the telecentric angle increases conflicting with other requirements
Solution Approach 1:
The third lens group with positive refractive power is positioned near the reduced side and specifically designed to control the exit angles of light rays. This segmented approach allows independent optimization of luminance uniformity and telecentric angle without compromising other system requirements
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 low lateral chromatic aberration, low distortion, a wide field of view, and a low telecentric angle, requiring only six or seven lenses, thereby reducing the overall size and fabrication costs while maintaining high image quality.
Implementation Method 1
a first lens group with a positive refractive power, a second lens group with a negative refractive power, and a third lens group with a positive refractive power
Data Source
AI summary
A lens module includes a first lens group with a positive refractive power, a second lens group with a negative refractive power, and a third lens group with a positive refractive power. The first lens group essentially consists of a first lens with a negative refractive power, a second lens with a positive refractive power and a third lens with a positive refractive power arranged in order from a magnified side to a reduced side. The second lens group essentially consists of a fourth lens with a negative refractive power and a fifth lens with a positive refractive power arranged in order from the magnified side to the reduced side. The third lens group essentially consists of a sixth lens with a positive refractive power and a seventh lens with a positive refractive power arranged in order from the magnified side to the reduced side.