Under-screen Fingerprint Optical Imaging System with Three Lenses
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Solution Overview
Problem
Traditional optical systems for under-screen fingerprint recognition in OLED screens have limitations such as large size, small field of view, and low imaging quality, which hinder the effectiveness of the recognition device.
Innovation Solution
An optical imaging system with three lenses, each with specific refractive powers and surface curvatures, is designed to provide a small size, large field of view, and high imaging quality, optimizing the focal lengths, aperture, and lens thicknesses to achieve desirable imaging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional optical system is used for under-screen fingerprint recognition, then the system can achieve basic recognition function, but the system has large size, small field of view, and low imaging quality
Solution Approach 1:
The optical system is divided into three separate lenses (first lens with negative refractive power, second lens with positive refractive power, third lens with positive refractive power) instead of using a single traditional lens. This segmentation allows each lens to be optimized for specific functions while achieving the overall goal of compact size with high imaging quality
Solution Approach 2:
The patent changes the refractive power parameters and curvature parameters of the lenses to achieve optimal performance. Specifically, the first lens has negative refractive power with a concave object-side surface, while the second and third lenses have positive refractive powers, creating a parameter optimization that reduces system size while improving imaging quality
2Area of stationary object
If a traditional optical system is used, then the structure is simple, but the field of view is small and aperture is limited
Solution Approach 1:
The optical system uses three segmented lenses with different refractive powers to achieve a large field of view (70 degrees or more) and large aperture (f/1.4 or less). The first lens with negative refractive power and the second and third lenses with positive refractive powers work together to expand the field of view while maintaining a compact structure
Solution Approach 2:
The patent introduces a multi-dimensional lens configuration where the first lens has a concave object-side surface and the second and third lenses have convex surfaces, creating a three-dimensional optical path that achieves both wide field of view and large aperture within a compact form factor
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 system achieves a larger imaging range with improved sensitivity and reduced aberrations, resulting in enhanced imaging quality and ultrathin design suitable for mobile devices.
Implementation Method 1
a first lens with a negative refractive power, an object-side surface thereof is a concave surface
Implementation Method 2
a second lens with a positive refractive power; and a third lens with a positive refractive power
Data Source
AI summary
The disclosure provides an optical imaging system, which sequentially includes from an object side to an image side along an optical axis: a first lens with a negative refractive power, an object-side surface thereof is a concave surface; a second lens with a positive refractive power; and a third lens with a positive refractive power; wherein an effective focal length f of the optical imaging system and, an Entrance Pupil Diameter (EPD) of the optical imaging system satisfy: f/EPD<1.6; an effective focal length f2 of the second lens and an effective focal length f3 of the third lens satisfy a conditional expression: 0.5<f2/f3<1.7; and Semi-FOV is a half of a maximum field of view of the optical imaging system satisfies: Semi-FOV>70°.