Ultrasonic Fingerprint Sensor Dynamic Resolution Control
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Solution Overview
Problem
Current ultrasonic fingerprint sensing systems face challenges in cost-efficient mass production and require flexible resolution control to meet varying application requirements, with existing technologies limiting power efficiency and accuracy.
Innovation Solution
A method and system that control ultrasonic transducers to adjust feature detection resolution dynamically, allowing for different modes such as touch detection, low-resolution, high-resolution, and enrolment, by activating specific transducers and varying power levels, enabling flexible and power-efficient fingerprint sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all ultrasonic transducers are activated to provide high resolution fingerprint detection across the entire sensing surface, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The sensing surface is divided into multiple zones, and the ultrasonic transducer array is segmented into corresponding groups. Each group can be independently controlled to activate only the transducers needed for detecting features in specific zones, thereby reducing overall power consumption while maintaining high resolution where required
Solution Approach 2:
The system dynamically adjusts the activation state of ultrasonic transducers based on detected touch characteristics. When a touch is detected, the system activates additional transducers to increase resolution for detailed fingerprint analysis. When no touch is present or only basic touch detection is needed, fewer transducers remain active, reducing power consumption
2Measurement precision
If ultrasonic transducers are activated to provide high feature detection resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Different resolution levels are applied to different regions of the sensing surface based on local requirements. High-resolution transducer groups are activated only in regions where detailed fingerprint features need to be detected, while other regions use lower resolution or remain inactive, simplifying the overall control architecture
Solution Approach 2:
The system changes operational parameters of the ultrasonic transducers, including activation states, excitation signal characteristics, and detection thresholds, to optimize the balance between resolution and complexity. By adjusting these parameters dynamically, the system achieves high measurement precision without requiring permanently complex control mechanisms
3Adaptability or versatility
If the sensing area is increased to provide larger fingerprint detection coverage, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The ultrasonic transducer array is segmented into multiple independent or semi-independent groups that can be manufactured and positioned with relaxed precision tolerances. Each group covers a specific zone of the sensing surface, and the overall large sensing area is achieved by combining multiple such groups rather than requiring one highly precise large-scale transducer array
Solution Approach 2:
The ultrasonic transducers are designed to serve multiple functions: they can operate in high-resolution mode for detailed fingerprint feature detection, low-resolution mode for basic touch detection, and can be selectively activated to cover different regions of the sensing surface. This multi-functionality allows a single transducer design to support large sensing area requirements without proportionally increasing manufacturing precision demands
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 approach allows for scalable resolution based on application needs, reducing power consumption and enhancing accuracy by selectively activating transducers and adjusting power, thereby improving the efficiency and adaptability of fingerprint sensing systems.
Implementation Method 1
a plurality of ultrasonic transducers located at the periphery of the cover plate, wherein the plurality of ultrasonic transducers are configured to transmit an acoustic signal propagating in the cover plate
Implementation Method 2
receive an ultrasonic signal having interacted with an object in contact with the sensing surface
Data Source
AI summary
A method for controlling a plurality of ultrasonic transducers in a fingerprint sensing system that comprises a cover plate having a sensing surface configured to be touched by a finger, and a plurality of ultrasonic transducers located at the periphery of the cover plate and configured to transmit an acoustic signal propagating in the cover plate, receive an ultrasonic signal having interacted with an object in contact with the sensing surface, and to determine properties of the object based on the received ultrasonic signal. The method comprises: in response to a first input, controlling the plurality of transducers such that at least a portion of the sensing surface has a first feature detection resolution; and in response to a second input, controlling the plurality of transducers such that at least a portion of the sensing surface has a second feature detection resolution, different from the first feature detection resolution.