Optical Imaging Lens Assembly for In-Screen Fingerprint Identification
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Solution Overview
Problem
Conventional optical imaging lens assemblies used in in-screen fingerprint identification devices suffer from poor imaging quality due to their large size, small field of view, and small aperture.
Innovation Solution
The optical imaging lens assembly consists of three lenses with specific refractive powers and surface types, optimized to achieve a total effective focal length and Entrance Pupil Diameter ratio of less than 1.5, and a maximum field of view between 140° and 160°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional optical imaging lens assembly is used, then the device structure is simple, but the imaging quality is poor due to large size, small field of view, and small aperture
Solution Approach 1:
The lens assembly is divided into three separate lenses with different refractive powers and surface characteristics. The first lens has negative refractive power with concave surfaces, while the second and third lenses have positive refractive power with convex surfaces. This segmentation allows each lens to be optimized for specific functions, achieving high imaging quality while maintaining a compact overall structure.
Solution Approach 2:
The patent optimizes specific parameters including the ratio of total effective focal length to entrance pupil diameter (f/EPD < 1.5), field of view (140°-160°), and the refractive powers of individual lenses. By carefully controlling these parameters, the system achieves miniaturization while maintaining large aperture and wide field of view, thereby improving imaging quality.
2Volume of moving object
If the lens assembly size is reduced for miniaturization, then the device becomes more compact, but the field of view and aperture are limited
Solution Approach 1:
The three lenses are arranged in a nested configuration along the optical axis, with the first lens positioned closest to the object side and the second and third lenses following in sequence. This nested arrangement allows the lens assembly to achieve a compact volume while maintaining large aperture and wide field of view through the optimized optical paths and surface characteristics of each lens.
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 ensures high imaging quality, miniaturization, and sufficient illumination, effectively addressing the limitations of conventional lens assemblies.
Implementation Method 1
a first lens with a negative refractive power, an object-side surface thereof is a concave surface, and an image-side surface thereof is a concave surface; a second lens with a positive refractive power
Data Source
AI summary
The disclosure provides an optical imaging lens assembly and a fingerprint identification device. The optical imaging lens assembly sequentially includes from an object side to an image side along an optical axis: a first lens with a negative refractive power; a second lens with a positive refractive power; and a third lens with a positive refractive power, an object-side surface thereof is a convex surface. A total effective focal length f of the optical imaging lens assembly and an Entrance Pupil Diameter (EPD) of the optical imaging lens assembly satisfy f/EPD<1.5. FOV is a maximum field of view of the optical imaging lens assembly, and FOV satisfies 140°<FOV<160°. By above reasonable arrangement, at least one of beneficial effects of large field of view, small size, large aperture, high imaging quality and the like of the optical imaging lens assembly is achieved.