Piezoelectric Sensor Electrode Edge Protrusion for Signal Integrity
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Solution Overview
Problem
Conventional piezoelectric sensors detecting pressure changes from a living body suffer from signal waveform alteration due to capacitive coupling between the pressure-sensitive layer and electrodes, leading to signal attenuation.
Innovation Solution
A piezoelectric sensor design where the edges of the electrodes protrude outside the pressure-sensitive layer, allowing electrical signals to propagate and be outputted without capacitive coupling interference, ensuring signal strength and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pressure-sensitive layer is disposed to cover the whole area of the electrodes, then the electrode structure can be simplified to detect pressure changes in a large area, but capacitive coupling occurs between the pressure-sensitive layer and electrodes, causing signal waveform distortion
Solution Approach 1:
The patent extracts the signal transmission path from the capacitive coupling field by making electrode edges protrude outside the pressure-sensitive layer. This allows the electrical signals to propagate through the protruding edges without being affected by the pressure-sensitive layer, thereby eliminating signal waveform distortion while maintaining the simplified electrode structure
Solution Approach 2:
The protruding edges of the electrodes serve as an intermediary transmission path for electrical signals. By extending the electrodes beyond the pressure-sensitive layer boundary, a dedicated signal propagation channel is created that is isolated from the capacitive coupling effects, enabling accurate signal transmission without distortion
2Reliability
If electrical signals propagate through electrodes covered by the pressure-sensitive layer, then the sensor structure remains compact, but signal attenuation occurs due to capacitive coupling effects
Solution Approach 1:
The patent extracts the signal transmission function from the capacitive coupling region by extending electrode edges outside the pressure-sensitive layer. This separation ensures that signals generated within the pressure-sensitive layer can propagate through the protruding edges without attenuation from capacitive effects, maintaining signal strength while preserving structural compactness
Solution Approach 2:
The patent introduces a dimensional extension by making electrode edges protrude beyond the pressure-sensitive layer boundary. This creates a three-dimensional configuration where the signal transmission path extends in the lateral dimension, bypassing the capacitive coupling zone and preventing signal attenuation
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 design effectively prevents signal attenuation, maintaining signal strength and enabling precise detection of biological signals like heartbeat and breathing, even at greater distances from the terminals.
Implementation Method 1
a pressure-sensitive layer disposed between the pair of electrodes and configured to generate electric charge in response to the change of pressure
Data Source
AI summary
A piezoelectric sensor configured to detect a change of pressure from a living body in a predetermined location includes: a pair of electrodes spaced from one another and formed to spread as a sheet; a pressure-sensitive layer disposed between the pair of electrodes and configured to generate electric charge in response to the change of pressure; a pair of terminals connected to the pair of electrodes, respectively, and configured to output an electrical signal supplied from the pair of electrodes in response to the change of pressure of the living body. An edge of at least one of the pair of electrodes extending toward the pair of terminals is disposed to protrude outside the pressure-sensitive layer, and the electrical signal propagates through the edge and is outputted from the pair of terminals.