Curved Capacitive Fingerprint Identification With Column Signal Control
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Solution Overview
Problem
Capacitive fingerprint identification apparatuses in planar structures suffer from single appearance, dust accumulation, misjudgment issues, and performance degradation due to uniform signal amounts and data saturation in non-planar surfaces.
Innovation Solution
A method for capacitive fingerprint identification that allocates a separate number of driving signals for each column of pixel electrodes based on their distance from a special-shaped surface, increasing signal amounts and controlling data levels for improved algorithm processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar structure is used for capacitive fingerprint apparatus, then the structure is simple and easy to manufacture, but the appearance is single and customer experience is not novel
Solution Approach 1:
The patent applies curvature to the fingerprint sensing surface by arranging pixel electrodes on an arc-shaped surface rather than a flat plane. This curved arrangement provides three-dimensional appearance and novelty while maintaining the underlying electrode structure's manufacturability through standardized arc-shaped layouts.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement to a three-dimensional arc-shaped arrangement of pixel electrodes. This dimensional change adds depth and spatial variation to the structure, creating novel appearance while the electrode pattern itself remains systematically organized for ease of manufacture.
2Device complexity
If a planar structure is used for capacitive fingerprint apparatus, then the structure is simple, but dust and substances are easily adsorbed causing misjudgment
Solution Approach 1:
The arc-shaped surface creates a curved geometry that prevents dust and substances from settling in flat surfaces. The curvature causes particles to roll off or be less likely to adhere, reducing contamination-related misjudgments while maintaining structural simplicity through a single arc-shaped design.
3Ease of operation
If uniform driving signals are applied to all pixel electrodes, then the control is simple, but signal amounts differ significantly on special-shaped surfaces causing poor fingerprint identification
Solution Approach 1:
The patent applies different driving signal parameters to different regions of the arc-shaped pixel electrode array. Specifically, pixel electrodes at different radial positions receive driving signals with adjusted amplitudes or frequencies compensated for their distance from the fingerprint contact surface, ensuring uniform signal quality across the curved geometry.
Solution Approach 2:
The patent modifies driving signal parameters (such as amplitude, frequency, or pulse width) based on the position of pixel electrodes along the arc. This parameter adjustment compensates for variations in capacitance caused by different distances from the fingerprint surface, maintaining measurement precision across the special-shaped surface.
4Device complexity
If the same number of driving signals is used for all columns, then the processing is simple, but data saturation with up and down fluctuations occurs on arc surfaces
Solution Approach 1:
The patent applies different numbers of driving signals to different columns of pixel electrodes based on their position along the arc. Columns at positions where data saturation would occur receive adjusted signal counts to flatten the data distribution, preventing information loss while keeping the processing logic systematic and manageable.
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
Enhances user experience and fingerprint identification performance by ensuring consistent signal levels and reducing data saturation on non-planar surfaces.
Implementation Method 1
the pixel electrode array is configured to form capacitance with a finger touching the special-shaped surface
Data Source
AI summary
A method for capacitive fingerprint identification. The method is applied to an electronic device with a capacitive fingerprint identification apparatus which has a special-shaped surface. The method includes: obtaining a number of driving signals N(i) of an ith column of pixel electrodes; and performing signal driving to the ith column of pixel electrodes to obtain an output voltage according to the number of driving signals N(i), the output voltage corresponds to the capacitor, and the output voltage is configured for fingerprint identification. The present application can controls a column average output voltage of the pixel electrode at a similar level, so as to facilitate algorithmic processing, at the same time, a risk of data saturation with up and down fluctuations is reduced, and thereby the performance of fingerprint identification is improved.