Three-Lens Optical System for Compact Biometric Identification
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Solution Overview
Problem
Current biometric identification systems in mobile devices face challenges due to complex circuit structures leading to high manufacturing costs and large volumes, making them difficult to miniaturize for electronic devices.
Innovation Solution
A three-piece compact optical lens system comprising a flat panel, a first lens element with negative refractive power, a stop, a second lens element with positive refractive power, and a third lens element with refractive power, optimized to reduce volume, correct aberrations, and improve image collection at large angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional optical imaging systems are used for biometric identification, then identification capability is achieved, but the system volume becomes too large for miniaturization
Solution Approach 1:
The optical lens system is divided into three separate lens elements with different refractive powers and aspheric surfaces. This segmentation allows each element to perform specific optical functions (correcting different types of aberrations, focusing light) while keeping the overall system compact. The first lens element with negative refractive power, second lens element with positive refractive power, and third lens element with refractive power work together to achieve compact biometric identification without requiring a large volume traditional optical system.
Solution Approach 2:
The patent employs aspheric surfaces on the lens elements, which introduces complex curvature variations in multiple dimensions rather than simple spherical surfaces. This dimensional complexity allows for better light control and aberration correction in a compact configuration, enabling the system to achieve effective biometric identification within a reduced volume by optimizing light paths through sophisticated surface geometries.
2Volume of stationary object
If capacitance-based biometric identification is used, then system volume is reduced, but manufacturing cost increases due to complex circuit structure
Solution Approach 1:
The patent replaces the capacitance-based electronic sensing system with an optical imaging system. Instead of using complex circuit structures and sensors that require sophisticated manufacturing processes, the invention uses purely optical components (lens elements with aspheric surfaces) to capture biometric information. This substitution of optical for electronic systems simplifies the manufacturing process while maintaining compact dimensions, as optical components can be manufactured using standard glass molding or precision machining techniques.
3Volume of stationary object
If optical lens system is miniaturized, then volume is reduced, but image collection capability at large angles deteriorates
Solution Approach 1:
The patent utilizes aspheric surfaces on all three lens elements, which feature complex curvature variations that differ from simple spherical shapes. These aspheric profiles are specifically designed to redirect light rays at large angles more effectively, allowing the compact lens system to collect light from wider fields of view. The curved aspheric surfaces bend light paths to ensure adequate illumination intensity is maintained across the image plane even when the system volume is minimized, thus preserving large-angle image collection capability.
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 effectively miniaturizes the biometric identification system, reduces manufacturing costs, and enhances image collection capabilities within short distances, achieving identification effects with improved resolution and reduced sensitivity.
Implementation Method 1
a first lens element with a negative refractive power
Implementation Method 2
a second lens element with a positive refractive power
Implementation Method 3
a third lens element with a refractive power
Implementation Method 4
at least one of an object-side surface and an image-side surface of the first lens element being aspheric
Data Source
AI summary
A three-piece compact optical lens system includes, in order from the object side to the image side: a flat panel assembly, a first lens element; a stop; a second lens element; and a third lens element. Wherein a distance from an object to an image plane along the optical axis is OTL, a distance from an image-side surface of the flat panel to the image plane along the optical axis is PTL, an image height of the image plane is Y, an object height of a chief ray of the image height of the image plane which corresponds to the image-side surface of the flat panel is P, and they satisfy the relations: 2.5 mm<PTL<4.5 mm; 2.2<P/Y<7.0; 4<OTL/Y<12.