Fingerprint Sensing Circuit Super-Pixel to Sub-Pixel Conversion
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Solution Overview
Problem
Fingerprint sensing devices face challenges in achieving high resolution and sensitivity due to the difficulty in accurately detecting changes in mutual capacitance at each node, especially when the distance between electrodes is reduced, leading to decreased sensitivity and accuracy in fingerprint recognition.
Innovation Solution
The method involves grouping driving electrodes into driving groups and detection electrodes into detection groups, applying electrical signals to these groups, and measuring signals from the detection groups to increase the area of activation and enhance signal intensity, thereby improving sensitivity and accuracy by converting image data from a super-pixel array to a sub-pixel array using a relationship matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between electrodes is reduced to increase resolution, then the resolution of fingerprint sensing is improved, but the sensitivity and accuracy of detecting mutual capacitance changes deteriorate
Solution Approach 1:
The patent merges multiple driving electrodes into driving groups and multiple detection electrodes into detection groups. By applying electrical signals to groups of electrodes rather than individual electrodes, the patent amplifies the signal intensity and mutual capacitance changes, thereby maintaining high sensitivity even when electrode spacing is reduced for higher resolution fingerprint sensing.
2Manufacturing precision
If individual nodes are activated for high resolution imaging, then the resolution is improved, but the signal intensity and sensitivity deteriorate
Solution Approach 1:
The patent combines multiple adjacent nodes into super-pixel arrays for imaging. By activating groups of nodes rather than individual nodes, the patent increases the total signal intensity and mutual capacitance changes detected, while still maintaining high resolution through the systematic processing and conversion of super-pixel data to sub-pixel data using relationship matrices.
3Manufacturing precision
If electrode spacing is decreased to increase the number of nodes, then the resolution is improved, but the difficulty of detecting mutual capacitance changes increases
Solution Approach 1:
The patent groups multiple detection electrodes into detection groups and processes signals collectively. This merging approach amplifies weak signals from closely-spaced electrodes, making mutual capacitance changes detectable even when electrode spacing is minimized for high-resolution fingerprint sensing.
Solution Approach 2:
The patent employs systematic processing of super-pixel array data through relationship matrices to reconstruct high-resolution sub-pixel images. This feedback-based processing approach compensates for the reduced signal strength from closely-spaced electrodes, maintaining detection accuracy despite decreased electrode spacing.
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 increases the sensitivity and accuracy of fingerprint recognition by effectively measuring mutual capacitance across multiple nodes, enhancing the resolution and reliability of fingerprint sensing devices.
Implementation Method 1
measuring capacitances at a plurality of activated nodes
Data Source
AI summary
A method and an apparatus for converting image data of a super-pixel array into image data a sub-pixel array are provided. A plurality of nodes in a separate activation area on a sensing circuit are activated to obtain a plurality of super-pixels and to generate image data of a super-pixel array including the plurality of super-pixels. Also, one or more nodes in an integrated activation area are separately activated to obtain values of sub-pixels in a first area of a sub-pixel array, and based on the super-pixel array and the values of the sub-pixels in the first area, the image data of the super-pixel array is converted into image data of the sub-pixel array.