Optical Lens Assembly Miniaturization with Aspherical Surfaces
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Solution Overview
Problem
The challenge is to design an optical lens assembly that is compact and efficient for applications such as face unlocking on mobile phones, automatic drive systems, and industrial machine vision, while minimizing space and maintaining high image quality, especially in environments with limited light.
Innovation Solution
The optical lens assembly consists of a sequence of lenses with specific refractive powers and surface shapes, including aspherical surfaces, arranged to optimize focal length, field of view, and aberration correction, with an infrared band pass filter to enhance imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the lens assembly size is reduced to minimize space occupation, then the screen-to-body ratio is improved and device compactness is enhanced, but the imaging quality and light collection capability deteriorate
Solution Approach 1:
The lens assembly is divided into multiple lenses with different refractive powers arranged in sequence. The first lens has positive refractive power, the second lens has negative refractive power, and the third lens has positive refractive power. This segmentation allows each lens to contribute to specific optical functions, achieving compact size while maintaining imaging quality through coordinated optical design.
Solution Approach 2:
The patent optimizes specific parameters including the refractive powers of each lens, the distances between lenses (T12, T23, T34), the focal length (f), and the f-number (FNO). By carefully controlling these parameters to satisfy specific relationships, the system achieves miniaturization while maintaining reliable imaging performance.
2Length of moving object
If the focal length is shortened to reduce lens assembly size, then the device compactness is improved, but the field of view and light gathering capability are reduced
Solution Approach 1:
Multiple lenses with different refractive powers are arranged in sequence to work together. The combination of positive and negative refractive power lenses allows the system to achieve a short focal length while maintaining an acceptable field of view, as each lens contributes to the overall optical path and light distribution.
Solution Approach 2:
The patent introduces transverse fields of view (FOV1, FOV2, FOV3) corresponding to different lenses, allowing the system to manage field of view in multiple dimensions. This approach enables optimization of both focal length and field of view by distributing optical functions across different spatial and optical dimensions.
3Reliability
If multiple lenses with different refractive powers are arranged to correct aberrations, then the image quality is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The lens assembly is segmented into three lenses with specific refractive power assignments. The first lens provides positive refractive power for initial light convergence, the second lens provides negative refractive power for aberration correction, and the third lens provides positive refractive power for final focusing. This segmentation distributes the optical functions to achieve effective aberration correction while controlling overall complexity.
Solution Approach 2:
Each lens is designed with specific local optical properties - different refractive powers and specific surface shapes (convex, concave, aspherical) - to address specific optical requirements at different positions in the optical path. This localized optimization allows effective aberration correction without requiring every lens to be overly complex.
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 configuration achieves miniaturization of the optical lens assembly, improves image quality, and allows for clear imaging in low-light conditions, balancing focal length and field of view while reducing production costs and weight.
Implementation Method 1
a first lens with a refractive power; a second lens with a positive refractive power; a third lens with a refractive power; a fourth lens with a positive refractive power
Implementation Method 2
an object side surface and an image side surface of the fourth lens are aspherical, and at least one of the object side surface and the image side surface of the fourth lens has an inflection point
Implementation Method 3
an infrared band pass filter to enhance imaging quality
Data Source
AI summary
An optical lens assembly, sequentially comprising from an object side to an image side: a first lens; a second lens having positive refractive power, the object side surface of the second lens being concave at the circumference, and the image side surface of the second lens being convex at the circumference; a third lens; and a fourth lens having positive refractive power, the image side surface of the fourth lens being concave at the optical axis, the object side surface and the image side surface of the fourth lens being aspherical, and at least one of the object side surface and the image side surface of the fourth lens having an inflection point. The optical lens assembly satisfies relationship: TT/f<1.3, TT is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fourth lens, and f is effective focal length.