Thermosensitive Fingerprint Sensing Without Heating Circuits
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Solution Overview
Problem
Thermal fingerprint-sensing apparatuses require heating devices and circuits to maintain sensing temperature, leading to prolonged sensing times and reduced recognition effectiveness due to thermal equilibrium.
Innovation Solution
A fingerprint-sensing apparatus with a fingerprint-sensing pixel array and read-out circuits that generate thermosensitive currents without the need for heating devices or circuits, utilizing scanning switches and thermosensitive current generation circuits to differentiate between fingerprint ridges and valleys, allowing for reduced sensing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating devices and heating circuits are used to maintain sensing temperature, then the thermal fingerprint-sensing apparatus can achieve fingerprint recognition, but the sensing time becomes prolonged and recognition effectiveness is reduced due to thermal equilibrium
Solution Approach 1:
The patent removes the heating devices and heating circuits from the thermal fingerprint-sensing apparatus. Instead of actively heating the sensing elements to a specified temperature, the invention directly utilizes the temperature differences between fingerprint ridges and valleys to generate thermosensitive currents, thereby eliminating the time-consuming heating process while maintaining fingerprint recognition capability
Solution Approach 2:
The conventional approach heats the sensing elements to a target temperature and then detects temperature variations. This patent inverts the approach by directly detecting the natural temperature differences between fingerprint ridges and valleys without prior heating, thus avoiding thermal equilibrium and reducing sensing time
2Stability of the object's composition
If a heating circuit is used to maintain multiple heating devices at a specified sensing temperature, then consistent sensing conditions are achieved, but the device complexity and energy consumption increase
Solution Approach 1:
The patent extracts and removes the heating circuit from the system entirely. The sensing apparatus no longer contains heating devices or heating circuits, simplifying the device structure while still achieving fingerprint recognition through direct detection of temperature differences between ridges and valleys
Solution Approach 2:
The fingerprint itself provides the temperature variation needed for sensing. The ridges and valleys naturally exhibit temperature differences due to their anatomical structure, eliminating the need for external heating circuits to create or maintain temperature conditions
3Measurement precision
If the sensing time is extended to ensure accurate fingerprint recognition, then recognition effectiveness is maintained, but thermal equilibrium is reached and recognition effect is reduced
Solution Approach 1:
The patent performs the temperature detection action immediately upon contact between the finger and the sensing apparatus. By directly measuring the temperature differences between ridges and valleys from the moment of contact, the system captures fingerprint information before thermal equilibrium can occur, eliminating the need for prolonged sensing time
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 solution enables efficient fingerprint sensing without heating devices, reducing overall sensing time and maintaining recognition effectiveness by generating distinct thermosensitive currents for fingerprint features.
Implementation Method 1
Each of the plurality of fingerprint-sensing pixels includes a scanning switch and a thermosensitive current generation circuit. The thermosensitive current generation circuit generates a the insensitive current according to the fingerprint-sensing pixel corresponding to a fingerprint ridge or a fingerprint valley.
Data Source
AI summary
A fingerprint-sensing apparatus is provided. The fingerprint-sensing apparatus includes a fingerprint-sensing pixel array and a plurality of read-out circuits. The fingerprint-sensing pixel array has a plurality of fingerprint-sensing pixel columns, and each of the plurality of fingerprint sensing pixel columns includes a plurality of fingerprint-sensing pixels. Each of the plurality of fingerprint-sensing pixels includes a scanning switch and a thermosensitive current generation circuit. The scanning switch is controlled by a row scanning signal. The thermosensitive current generation circuit generates a thermosensitive current according to the fingerprint-sensing pixel corresponding to a fingerprint ridge or a fingerprint valley. The plurality of read-out circuits is respectively coupled to the plurality of fingerprint-sensing pixel columns. The read-out circuits receive the thermosensitive current provided by the fingerprint-sensing pixels and generate a fingerprint-sensing signal according to the thermosensitive current.