Thin Optical Lens System with Intermediate Aperture Stop
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Solution Overview
Problem
Conventional mobile phone camera optical lens systems face challenges in reducing volume while maintaining high image quality, as they often suffer from stray light and sensitivity issues due to the arrangement of the front aperture stop, which complicates aberration correction and increases the complexity of the optical design.
Innovation Solution
A thin type optical lens system comprising three lens elements with specific refractive powers and aspheric surfaces, including a first lens with positive refractive power, an aperture stop, a second lens with negative refractive power, and a third lens with negative refractive power, optimized to balance aberrations and reduce the total optical length, using plastic or glass materials to correct chromatic aberration and miniaturize the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the aperture stop is arranged at the front of the optical lens system to correct aberration, then aberration correction is improved, but stray light increases and sensitivity becomes relatively high
Solution Approach 1:
The patent extracts the aperture stop from the conventional front position and relocates it to an intermediate position between the first and second lens elements. This extraction from its traditional location allows the system to maintain aberration correction capabilities while reducing stray light issues associated with front aperture stop arrangements.
Solution Approach 2:
The patent introduces an intermediate aperture stop position that acts as a mediator between the front lens elements and the sensor. This intermediate positioning serves as a compromise solution that balances aberration correction requirements with stray light reduction, neither placing the stop at the extreme front nor at the image plane.
2Volume of stationary object
If the optical lens system is miniaturized to reduce volume, then the system size is reduced, but image quality and resolution become more difficult to maintain
Solution Approach 1:
The patent employs aspheric surfaces on the second and third lens elements, changing the geometric parameters from spherical to aspheric profiles. This parameter change allows for better aberration control and image quality maintenance in a miniaturized system, as aspheric surfaces provide additional degrees of freedom for optimizing light paths in compact configurations.
Solution Approach 2:
The patent uses a combination of positive and negative refractive power lens elements that dynamically balance each other's aberrations. The second and third lens elements with negative refractive power counteract the aberrations introduced by the first lens element with positive refractive power, enabling compact design while maintaining image quality.
3Quantity of substance
If the pixel size of sensors is reduced to increase resolution, then miniaturization is achieved, but the demand for image quality increases
Solution Approach 1:
The patent applies aspheric surfaces specifically to the second and third lens elements where they are most needed for correcting off-axis aberrations. This localized application of advanced optical design techniques optimizes the light paths reaching the high-density pixel array, ensuring that each pixel receives properly corrected light for maintaining image quality despite reduced pixel size.
4Length of stationary object
If the total optical length is shortened to reduce system volume, then miniaturization is improved, but aberration correction becomes more challenging
Solution Approach 1:
The patent segments the optical system into three distinct lens elements with alternating positive and negative refractive powers. This segmentation allows each element to be optimized for specific functions: the first element provides positive power and initial focusing, while the second and third elements with negative power correct aberrations. This segmented approach enables effective aberration correction despite the shortened total optical length.
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 the volume of the optical lens system, enhancing photosensitivity, and correcting aberrations, while allowing for a wider field of view and reduced sensitivity, making it suitable for miniaturized camera applications.
Implementation Method 1
a first lens element with positive refractive power; a second lens element with negative refractive power; a third lens element with negative refractive power
Implementation Method 2
a second lens element with negative refractive power having at least one aspheric surface; a third lens element with negative refractive power having at least one aspheric surface
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 lens element with positive refractive power, a second lens element with negative refractive power having at least one aspheric surface, a third lens element with negative refractive power having at least one aspheric surface, and an aperture stop located between the first lens element and the second lens element. By such arrangements, it can effectively reduce the volume and the sensitivity of the lens system.