Aspherical Lens Module with Aperture Stop for CRA Reduction
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Solution Overview
Problem
Existing camera modules in mobile devices face challenges in achieving high resolution while being miniaturized and lightweight, with a need to minimize optical full length and chief ray angle (CRA) while maintaining low costs.
Innovation Solution
A camera module design comprising an aperture stop, a first lens with positive refractive power, a second lens with negative refractive power, and a third lens with negative refractive power, all formed as aspherical lenses to optimize optical characteristics, with the aperture stop located on the object side to reduce CRA and minimize optical full length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical system is miniaturized to reduce size and weight, then the camera module becomes more suitable for mobile devices, but the resolution and optical quality deteriorate
Solution Approach 1:
The optical system is divided into multiple lens elements (first lens L1, second lens L2, third lens L3) with alternating positive and negative refractive powers. This segmentation allows each element to contribute differently to the overall optical performance, enabling resolution maintenance while reducing total optical length through optimized light path management.
Solution Approach 2:
The patent employs aspherical lens surfaces with specifically optimized curvature radii and refractive indices. By changing the geometric parameters of the lens surfaces from traditional spherical to aspherical shapes, the system achieves better light convergence and reduced aberrations within a compact form factor, maintaining high resolution despite miniaturization.
2Measurement precision
If the aperture stop is positioned to reduce chief ray angle, then image sensor efficiency improves, but optical full length increases
Solution Approach 1:
The aperture stop is dynamically positioned at the object side of the first lens rather than in traditional intermediate positions. This strategic placement changes the chief ray trajectory, reducing the chief ray angle at the image sensor plane. The alternating positive-negative lens configuration then dynamically adjusts the light path to compensate for the increased optical length, achieving both reduced CRA and maintained compactness.
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 achieves high-resolution optical characteristics with reduced optical full length and CRA, enhancing image sensor efficiency and reducing distortion, while maintaining a compact size and low costs, suitable for subminiature camera modules in mobile devices.
Implementation Method 1
a first lens having a positive refractive power to transmit light that has passed through the aperture stop
Implementation Method 2
a second lens having a negative refractive power to transmit light that has passed through the first lens
Implementation Method 3
a third lens having a negative refractive power to transmit light that has passed through the second lens
Implementation Method 4
an image sensor for detecting light that has passed through the third lens
Data Source
AI summary
Provided is a camera module. The camera module includes an aperture stop, a first lens, a second lens, a third lens, and an image sensor. The first lens has a positive refractive power to transmit light that has passes through the aperture stop, and the second lens has a negative refractive power to transmit light that has passed through the first lens. The third lens has a negative refractive power to transmit light that has passed through the second lens. The image sensor detects light that has passed through the third lens.