Imaging Lens System for Under-Screen Fingerprint Miniaturization
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Solution Overview
Problem
Existing imaging lens systems for under-screen fingerprint identification have a relatively long total optical length, which hinders the miniaturization of lens systems.
Innovation Solution
The proposed imaging lens system, from the object side to the imaging plane, consists of a flat glass, a first lens with negative focal power, a second lens with positive focal power, a stop, and a third lens with positive focal power. The system meets specific optical parameters, including f/EPD≤1.64, 0<BFL/IH<0.2, and other expressions that optimize lens design and reduce optical length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional imaging lens system design is used, then image capture function is achieved, but total optical length becomes relatively long
Solution Approach 1:
The imaging lens system is divided into multiple lens elements (first lens with negative focal power, second lens with positive focal power, third lens with positive focal power) and a stop, allowing each component to contribute differently to the overall optical function. This segmentation enables compact arrangement while maintaining imaging performance.
Solution Approach 2:
The patent specifies particular parameter ranges including f/EPD≤1.64, 0<BFL/IH<0.2, and specific curvature radius relationships (0.3<R12/R11<0.6, -0.6<R22/R21<-0.3) to optimize the optical system. These parameter constraints enable miniaturization while preserving image capture capability.
2Length of moving object
If lens miniaturization is pursued, then total optical length is reduced, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent establishes specific parameter ranges for curvature radii (R11, R12, R21, R22, R31, R32) and their ratios, along with thickness constraints (0.05<C1<0.15, 0.05<C2<0.15). These well-defined parameters provide clear manufacturing targets that balance miniaturization with manufacturability.
Solution Approach 2:
The design allows flexibility within specified parameter ranges rather than fixing exact values, enabling manufacturing adjustments while staying within the optimal design space for both size and precision requirements.
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 optimized imaging lens system achieves a shorter total optical length, facilitating the miniaturization of lens systems while maintaining effective image capture and fingerprint recognition performance.
Implementation Method 1
a first lens, where the first lens has a negative focal power
Implementation Method 2
a second lens, where the second lens has a positive focal power
Implementation Method 3
a third lens, where the third lens has a positive focal power
Data Source
AI summary
An imaging lens system, from an object side to an imaging plane, sequentially includes: a flat glass; a first lens with a negative focal power, a convex object side surface and a concave image side surface; a second lens with a positive focal power, a convex object side surface and a concave image side surface; a stop; a third lens with a positive focal power and a convex image side surface. The imaging lens system meets expressions: f/EPD≤1.64; 0<BFL/IH<0.2; where f represents an effective focal length of the imaging lens system, and EPD represents an entrance pupil diameter of the imaging lens system; BFL represents a distance from a vertex of the image side surface of the third lens to the imaging plane on the optical axis, and IH represents the maximum image height of the imaging lens system.