Four-Lens Optical System with Inflection Points for Compact Imaging
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Solution Overview
Problem
Traditional optical image capturing systems for portable electronic devices face challenges in achieving high pixel counts, better image quality, and balanced design with minimized size, while also effectively handling visible and infrared light without the need for IR cut filters, which are costly and space-consuming.
Innovation Solution
The use of a combination of refractive powers, convex, and concave surfaces in a four-piece optical lens system with specific lens element positioning and materials to increase light admission and angle of view, allowing for improved image quality and reduced size, and achieving a near 'confocal' effect without IR cut filters by minimizing the difference in focal lengths for visible and infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large aperture design is used to increase light admission, then the amount of light admitted is improved, but optical aberration increases and peripheral image quality deteriorates
Solution Approach 1:
The optical system is divided into multiple lens elements (first lens element, second lens element, third lens element, fourth lens element) with different refractive powers and surface curvatures. Each lens element is designed to address specific aberrations, collectively achieving both high light admission and good peripheral image quality.
Solution Approach 2:
Different regions of the optical system are optimized with specific lens characteristics. The first lens element has a convex object-side surface and concave image-side surface for specific aberration correction, while the fourth lens element has inflection points to control off-axis ray angles. Each lens is locally optimized for its specific function in the overall system.
2Adaptability or versatility
If a wide view angle design is used to increase the angle of view, then the field of view is improved, but distortion rate increases
Solution Approach 1:
The optical system uses multiple lens elements with different functions: the first lens element handles wide angle coverage, while subsequent lens elements progressively correct distortion and aberrations. This segmentation allows the system to achieve wide view angle without excessive distortion.
Solution Approach 2:
The lens elements utilize specific surface curvatures, including convex and concave surfaces as well as inflection points on the fourth lens element. These curved surfaces are designed to control ray paths and minimize distortion while maintaining wide field of view.
3Adaptability or versatility
If IR cut filters are used to handle infrared light, then infrared light handling is improved, but device complexity and size increase
Solution Approach 1:
The patent removes the IR cut filter from the optical system entirely. Instead of using a filter to block unwanted infrared light, the system uses a four-lens configuration where the fourth lens element with inflection points is specifically designed to handle both visible and infrared light, extracting the filtering function from the mechanical structure.
Solution Approach 2:
The fourth lens element acts as an intermediary that handles both visible and infrared light without requiring separate filtering mechanisms. The inflection points on this lens element serve as a mediating structure that controls ray paths for different wavelengths, eliminating the need for additional IR cut filters.
4Measurement precision
If pixel size is minimized to increase total pixel count, then the resolution is improved, but the camera module size cannot be minimized
Solution Approach 1:
The patent optimizes the refractive indices and curvatures of the lens elements to achieve high light admission and good image quality with a compact optical path. By changing the optical parameters (refractive powers, surface curvatures, lens spacing), the system achieves high resolution with minimal module size.
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
This solution enhances the relative illumination, total pixel count, and image quality, enabling the optical image capturing system to be compact and suitable for miniaturized electronic products while maintaining high image quality across both visible and infrared spectrums.
Implementation Method 1
The optical image capturing system includes a first lens element, a second lens element, a third lens element, and a fourth lens element with refractive power
Data Source
AI summary
A four-piece optical lens for capturing image and a five-piece optical module for capturing image are provided. In the order from an object side to an image side, the optical lens along the optical axis includes a first lens with positive refractive power; a second lens with refractive power; a third lens with refractive power; and a fourth lens with refractive power; and at least one of the image-side surface and object-side surface of each of the four lens elements are aspheric. The optical lens can increase aperture value and improve the imagining quality for use in compact cameras.