Aspheric Lens System with Interposed Aperture Stop for Stray Light Control
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Solution Overview
Problem
Conventional mobile phone optical lens systems suffer from increased stray light and sensitivity due to the arrangement of the front aperture stop, which affects image quality and aberration correction.
Innovation Solution
A three-lens optical system with specific refractive power configurations and aspheric surfaces, including a first lens with positive refractive power, a second lens with negative refractive power, and a third lens with positive refractive power, where the aperture stop is located between the first and second lenses to control brightness and reduce sensitivity, and the use of plastic materials for miniaturization and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the aperture stop is arranged at the front of the optical lens system, then the aberration can be corrected, but the stray light and sensitivity increase
Solution Approach 1:
The aperture stop is extracted from the conventional front position and relocated to a position between the first and second lens elements. This extraction removes the harmful effect of stray light and increased sensitivity while maintaining the aberration correction capability through the optimized lens configuration.
Solution Approach 2:
The first lens element with positive refractive power acts as an intermediary between the aperture stop and the image plane. This intermediary structure helps control the light paths, reducing stray light while maintaining aberration correction when the aperture stop is positioned between the first and second lens elements.
2Length of moving object
If the optical lens system is miniaturized, then the thickness is reduced, but the image quality and aberration correction become more difficult to maintain
Solution Approach 1:
The lens elements utilize aspheric surfaces with specific curvature parameters and refractive indices that allow for effective aberration correction in a compact form. The aspheric coefficients and radius of curvature are optimized to maintain image quality while reducing the overall optical system thickness.
Solution Approach 2:
The optical system employs lens elements with different refractive indices and aspheric surface configurations to achieve superior aberration correction in a miniaturized format. The combination of plastic lens materials with optimized optical properties enables compact design without sacrificing image quality.
3Measurement precision
If the pixel size of photosensitive assembly is reduced, then the resolution increases, but the demand for image quality becomes more urgent
Solution Approach 1:
The aspheric surface parameters and lens element configurations are specifically optimized to deliver high image quality that matches the increased resolution capability of smaller pixel photosensitive assemblies. The precise control of optical parameters ensures that the reduced pixel size does not result in degraded image quality.
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 improves image quality by reducing aberrations, increasing photosensitivity, and minimizing the length of the optical lens system while correcting chromatic and spherical aberrations, thus enhancing the overall performance of the camera phone's image capture capabilities.
Implementation Method 1
a first lens element with positive refractive power having a convex front surface and a concave rear surface, the front surface of the first lens being aspheric
Implementation Method 2
an aperture stop of the optical lens system is located between the first lens element and the second lens element for controlling the brightness of the optical system
Data Source
AI summary
An optical lens system for taking image comprises three lens elements with refractive power, from the object side to the image side: a first positive lens element having a convex front surface and a concave rear surface, and the front surface being aspheric; a negative plastic second lens element having a concave front surface and a convex rear surface, and the front and rear surfaces thereof being aspheric; a positive plastic third lens element having a convex front surface and a concave rear surface, the front and rear surfaces thereof being aspheric; and an aperture stop located between the first and second lens elements for controlling brightness of the optical system. The focal length of the first lens element is f1, the focal length of the optical lens system is f, and they satisfy the relations: f/f1<0.9.