Two-Lens Optical Assembly for Compact Biometric Imaging
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Solution Overview
Problem
Existing biometric identification systems in mobile devices rely on capacitive sensing, which results in complex circuit structures and high manufacturing costs, while traditional optical imaging systems are bulky, making it difficult to miniaturize electronic devices.
Innovation Solution
An optical lens assembly with two lenses having refractive power, specifically a first lens with negative refractive power and a second lens with positive refractive power, designed to achieve a compact size and enhanced image quality while allowing for use at extreme temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical imaging systems are used for biometric identification, then image quality can be achieved, but the system volume becomes too large
Solution Approach 1:
The optical lens assembly is divided into only two essential lenses with refractive power, eliminating unnecessary optical elements. This segmentation approach keeps only the critical components needed for fingerprint imaging, thereby reducing overall system volume while maintaining image quality
Solution Approach 2:
The patent employs asymmetric lens design where the first lens has negative refractive power and the second has positive refractive power. This dimensional change in optical power distribution allows compact arrangement of optical elements along the optical axis, achieving short total track length without compromising imaging performance
2Volume of stationary object
If capacitive sensing technology is used, then the volume of biometric identification system is reduced, but the circuit structure becomes too complex
Solution Approach 1:
The patent replaces complex electronic capacitive sensing circuits with a simplified optical imaging system. By using pure optical components (two lenses) to capture fingerprint images, the invention eliminates the need for complex capacitive sensing circuitry, thereby reducing both volume and circuit complexity simultaneously
Solution Approach 2:
The invention extracts and removes the complex capacitive sensing circuitry from the biometric identification system, retaining only the essential optical components needed for fingerprint capture. This extraction simplifies the overall system architecture while maintaining functionality
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 assembly achieves a compact size, enhances image quality, and allows for operation at extreme temperatures, addressing the cost and miniaturization challenges of existing biometric identification systems.
Implementation Method 1
a first lens with negative refractive power, including an object-side surface and an image-side surface, the image-side surface of the first lens being convex in a paraxial region thereof
Implementation Method 2
a second lens with positive refractive power, including an object-side surface and an image-side surface, the object-side surface of the second lens being convex in a paraxial region thereof, the image-side surface of the second lens being convex in a paraxial region thereof
Implementation Method 3
at least one of the object-side surface and the image-side surface of the first lens being aspheric; and at least one of the object-side surface and the image-side surface of the second lens being aspheric
Data Source
AI summary
An optical lens assembly includes a stop, and in order from an object side to an image side, includes: a first lens with negative refractive power; a second lens with positive refractive power; wherein the optical lens assembly has a total of two lenses with refractive power, a radius of curvature of an object-side surface of the first lens is R1, a radius of curvature of an image-side surface of the first lens is R2, a radius of curvature of an image-side surface of the second lens is R4, and the following condition is satisfied: −1.45 mm<(R1/R4)*R2<−0.34 mm.