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 volume, 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 positive refractive power, designed to reduce volume, increase view angle, and correct aberrations for effective miniaturization and image collection.
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 (first lens element with negative refractive power, second and third lens elements with positive refractive power). This segmentation allows each element to be optimized for specific functions while collectively achieving compact form factor and biometric identification capability
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens elements and carefully controls the refractive power distribution (first element: negative, second and third: positive) to achieve both miniaturization and effective light collection. The specific parameter relationships (f1+f2+f3)/(f1*f2*f3) within specified ranges optimize the balance between compactness and imaging performance
2Volume of stationary object
If the distance between object and lens system is reduced for compactness, then miniaturization is achieved, but light collection ability and image quality deteriorate
Solution Approach 1:
The optical system is designed to dynamically adapt to short object distances through its specific lens element configuration. The combination of negative and positive refractive power elements creates flexible light path control that maintains effective light collection even when the object distance is minimized for compact device integration
Solution Approach 2:
The system uses composite optical design with three different lens elements having distinct refractive power characteristics (negative, positive, positive). This composite approach enables the system to overcome the limitations of single-element lenses at short distances while maintaining compact volume
3Manufacturing precision
If more lens elements are added to improve image quality, then aberration correction improves, but device complexity and manufacturing cost increase
Solution Approach 1:
Aspheric surfaces are selectively applied to specific lens elements (first, second, and/or third elements) rather than all surfaces. This local application of complex geometry targets the most critical aberration-prone areas while keeping other surfaces simpler, thereby improving image quality without proportionally increasing manufacturing complexity across the entire system
Solution Approach 2:
The patent uses exactly three lens elements with aspheric surfaces strategically positioned to correct the most significant aberrations. This partial approach focuses computational and manufacturing resources on the most critical correction needs rather than attempting perfect correction across all possible aberration types, optimizing the balance between image quality and complexity
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 compact design, allowing for wider angle image collection and effective identification at short distances, while reducing manufacturing costs and improving image quality by balancing refractive power and correcting aberrations.
Implementation Method 1
a first lens element with a negative refractive power having an object-side surface being concave near an optical axis
Implementation Method 2
a second lens element with a positive refractive power having an object-side surface being convex near the optical axis and an image-side surface being convex near the optical axis
Implementation Method 3
a third lens element with a positive refractive power, at least one of an object-side surface and an image-side surface of the third 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 made of glass, a first lens element with a negative refractive power having an object-side surface being concave near an optical axis; a stop; a second lens element with a positive refractive power having an object-side surface being convex near the optical axis and an image-side surface being convex near the optical axis; and a third lens element with a positive refractive power. Such a system can not only effectively collect light at a large angle, receive a wider range of images and achieve identification effects within very short distances, but also can reduce the distance between an object and the three-piece compact optical lens system, reduce the volume effectively and maintain its miniaturization.