Three-Lens Optical System for Under-Display Fingerprint Recognition
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Solution Overview
Problem
Existing optical lenses for under-display fingerprint recognition face challenges in accuracy due to their design limitations, which affect the performance of image capturing devices in smart apparatuses.
Innovation Solution
A compact optical lens system comprising a first lens with negative refractive power, a second lens with positive refractive power, and a third lens with positive refractive power, optimized with specific focal length and diameter conditions, along with an aperture stop, to achieve a wide-angle view and reduce aberration, suitable for under-display optical fingerprint recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical lenses are used for under-display fingerprint recognition, then the device structure is simple, but the image resolving ability and recognition accuracy are insufficient
Solution Approach 1:
The optical lens is divided into three separate lens elements (first lens with negative refractive power, second lens with positive refractive power, and third lens with positive refractive power) arranged in sequence along the optical axis. This segmentation allows each lens element to contribute differently to the overall optical performance, improving image resolving ability and fingerprint recognition accuracy while maintaining a compact structure suitable for under-display applications
2Area of stationary object
If the optical lens is designed with wide-angle and short object distance, then the field of view is enlarged, but the aberration increases
Solution Approach 1:
Each lens element is designed with specific local optical properties: the first lens has negative refractive power to diverge light and expand field of view, the second lens has positive refractive power to converge light and correct aberrations, and the third lens has positive refractive power to further focus light. The combination of these different local qualities allows the system to achieve wide-angle viewing while controlling optical aberration
Solution Approach 2:
The patent specifies particular parameter ranges for the lens elements including focal lengths (f1, f2, f3), diameters (D1, D2, D3), and spacing distances (T12, T23) that satisfy specific mathematical conditions. By optimizing these parameters, the system achieves a balance between enlarging the field of view and minimizing optical aberration, enabling effective under-display fingerprint recognition
3Manufacturing precision
If multiple lenses are used to improve image quality, then the image resolving ability is enhanced, but the lens size and manufacturing complexity increase
Solution Approach 1:
The three-lens optical system is designed to perform multiple functions within a compact structure: the first lens expands the field of view and provides initial light divergence, the second lens corrects aberrations and provides intermediate focusing, and the third lens delivers final image formation. This multi-functional design achieves high image resolving ability suitable for fingerprint recognition while keeping the overall lens size small and the structure manufacturable
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 optical lens system enhances image resolving ability, enlarges the field of view, and reduces aberration, making it suitable for under-display applications while maintaining a small size and requiring only three lenses, thus improving the accuracy of fingerprint recognition.
Implementation Method 1
The first lens is a lens having negative refractive power, and an object-side surface of the first lens is concave
Implementation Method 2
the second lens is a lens having positive refractive power
Implementation Method 3
the third lens is a lens having positive refractive power, and an image-side surface of the third lens is convex
Data Source
AI summary
An optical lens includes a first lens, a second lens and a third lens in an order from an object side to an image side along an optical axis. The first lens is a lens having negative refractive power, and an object-side surface of the first lens is concave; the second lens is a lens having positive refractive power, and an image-side surface of the second lens is convex; the third lens is a lens having positive refractive power, and an image-side surface of the third lens is convex. The optical lens satisfies a condition. i.e., 3<D1/f<6, wherein D1 is an optical effective diameter of the first lens and f is effective focal length of the optical lens. The optical lens is characterized by wide-angle and short distance.