2D Finger Motion Tracking Using Segmented Partial Fingerprint Readers
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Solution Overview
Problem
Existing partial fingerprint sensors face challenges in accurately sensing finger swiping motion and calculating speed and location due to human factors variations, and there is a need for more efficient fingerprint capture and navigation on portable devices with limited space, power, and cost constraints.
Innovation Solution
The use of multiple partial fingerprint readers arranged in different directions to detect finger motion in two dimensions, combined with algorithms to analyze output and provide finger motion information for controlling electronic devices, allowing for precise navigation and fingerprint reconstruction with reduced processing resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple partial fingerprint readers are arranged in different directions to detect finger motion in two dimensions, then measurement precision of finger motion and location is improved, but device complexity increases
Solution Approach 1:
The fingerprint sensor is divided into multiple independent linear sensor arrays oriented in different directions (e.g., horizontal and vertical). Each array independently detects motion along its axis, and the results are combined to provide comprehensive 2D motion tracking. This segmentation allows each sensor to be simple while the collective system achieves high measurement precision.
Solution Approach 2:
The system transitions from single-dimension linear sensing to multi-dimensional motion detection by arranging sensor arrays in multiple orientations. By combining data from sensors oriented in different directions, the system achieves complete 2D motion tracking capability, resolving the contradiction between simple sensor elements and comprehensive measurement.
2Ease of manufacture
If partial fingerprint sensors are used to reduce size and cost, then manufacturing cost and device size are reduced, but measurement precision of fingerprint capture deteriorates
Solution Approach 1:
Instead of using a single large sensor array, the system employs multiple smaller linear sensor arrays that can be independently manufactured and then combined through software processing. This segmentation enables the use of smaller, less expensive sensor elements while achieving comprehensive fingerprint capture through their coordinated operation.
Solution Approach 2:
Multiple linear sensor arrays create overlapping samples of the fingerprint as it moves across the sensor surface. These redundant copies allow for improved image reconstruction through algorithms that combine the data from multiple sources, achieving high measurement precision despite using smaller, cheaper sensor elements.
3Measurement precision
If finger motion tracking algorithms process multiple sensor arrays, then measurement precision of motion detection is improved, but use of energy increases
Solution Approach 1:
The processing system handles multiple sensor arrays independently, processing each linear array's data separately before combining the results. This segmented processing approach reduces the computational burden on any single processing unit and allows for more efficient energy management compared to processing a single large complex array.
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 enables accurate and efficient finger motion sensing and fingerprint capture on small, low-power devices, enhancing user identification and control operations while minimizing space and power consumption.
Implementation Method 1
Other devices include one or two dimensional arrays of optical sensors that read light reflected off of a person's finger and onto an array of optical detectors
Implementation Method 2
These devices create sensing elements by creating a linear array composed of many miniature excitation electrodes, spaced at a high density, such as a density of approximately 500 electrodes per inch. The tips of these electrodes are separated from a single sensing electrode by a small sensor gap. The electrodes are electrically excited in a progressive scan pattern and the ridges and valleys of a finger pad alter the electrical properties (usually the capacitive properties) of the excitation electrode-sensing electrode interaction
Data Source
AI summary
A sensor which uses a plurality of partial fingerprint readers (imagers), and various computational algorithms, to detect changes in fingerprint images as a function of finger movement. The sensor can provide both finger motion information and fingerprint images. The sensor uses multiple partial fingerprint readers, arranged in different directions on a surface, to detect finger motion in two dimensions. The sensor can also detect the relative speed and direction of finger movement. Some sensor embodiments use deep finger penetrating radio frequency (RF) based circuits, which can be inexpensively printed or formed on the surface of robust and flexible dielectric materials such as Kapton tape. The sensor also has textured surfaces to help guide the user. The sensor both small and robust, and is well suited for control applications for low-cost mass market microprocessor controlled devices such as cell phones, MP3 players, laptop computers, and other devices.