Fingerprint Detection Electrode Placement on Substrate Surfaces
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Solution Overview
Problem
Existing fingerprint detection devices in electronic apparatuses face limitations due to the arrangement of detection electrodes and circuits, which restrict the use of transparent substrates for both fingerprint detection and display functions, leading to reduced detection sensitivity and increased parasitic capacitance.
Innovation Solution
A fingerprint detection device is designed with detection electrodes on one surface of a substrate and drive circuits on the opposite surface, allowing for efficient electrostatic capacitance-based fingerprint detection without conductive lines on the detection surface, thereby reducing parasitic capacitance and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If detection electrodes and drive circuits are provided on the same surface of the substrate, then the device structure is simplified, but parasitic capacitance increases and detection sensitivity deteriorates
Solution Approach 1:
The substrate is divided into two functional surfaces: the first surface is dedicated to fingerprint detection with detection electrodes, while the second surface houses the drive circuit. This segmentation separates the detection function from the driving function, eliminating parasitic capacitance interference and improving detection sensitivity.
2Adaptability or versatility
If detection electrodes are arranged above switching elements on the transparent substrate, then the substrate can serve dual purposes, but the detection surface arrangement is limited
Solution Approach 1:
The invention transitions from a two-dimensional arrangement where detection electrodes and switching elements share the same surface layer to a three-dimensional configuration utilizing both surfaces of the substrate. Detection electrodes are placed on the first surface while switching elements are on the second surface, enabling flexible detection surface arrangement without compromising substrate versatility.
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 configuration enables improved fingerprint detection sensitivity and reduced detection errors by minimizing parasitic capacitance and allowing for a more flexible arrangement of components, while maintaining the transparency of the detection surface for display purposes.
Implementation Method 1
a detection electrode provided on the second surface side of the substrate and configured to detect unevenness of a finger in contact or in proximity on the basis of an electrostatic capacitance change
Data Source
AI summary
A fingerprint detection device includes: a substrate having a first surface and a second surface on an opposite side of the first surface, the first surface serving as a detection surface configured to detect unevenness of an object in contact or in proximity; a detection electrode provided on the second surface side of the substrate and configured to detect unevenness of a finger in contact or in proximity on the basis of an electrostatic capacitance change; and a drive circuit provided on the second surface side of the substrate and configured to supply a drive signal to the detection electrode.