Pressure Sensor Electrode Layout for Accurate Low-Cost Detection
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Solution Overview
Problem
Existing pressure sensors in display devices face challenges in achieving high sensitivity while maintaining low manufacturing costs, as the variations in resistance values can lead to inaccurate pressure detection and increased production costs.
Innovation Solution
The pressure sensor design includes a first and second substrate with specific electrode configurations and pressure sensing layers, where the second pressure sensing layer is electrically coupled to the driving and sensing electrodes, and a conductive layer with lower resistance than the pressure sensing layers, optimizing the resistance range and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pressure sensing cells with large resistance value variations are used, then manufacturing cost is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces a conductive layer with specifically controlled resistance (lower than pressure sensing layers but higher than driving/sensing electrodes) to adjust and optimize the overall resistance characteristics of the pressure sensing cell. This parameter adjustment enables accurate pressure detection while maintaining cost-effective manufacturing by using materials with appropriate resistance ranges.
Solution Approach 2:
The pressure sensing cell employs a composite structure combining multiple layers with different resistance characteristics: pressure sensing layers, driving electrodes, sensing electrodes, and a conductive layer. This composite approach allows each layer to contribute its specific electrical properties, achieving optimal overall performance for both accuracy and cost-effectiveness.
2Measurement precision
If pressure sensing layers with high resistance are used, then sensitivity to pressure is improved, but electrical conductivity deteriorates
Solution Approach 1:
The conductive layer's resistance is specifically designed to fall between the resistance values of the pressure sensing layers and the driving/sensing electrodes. This intermediate resistance value optimizes the electrical conductivity of the entire sensing cell while preserving the high sensitivity characteristics of the pressure sensing layers.
Solution Approach 2:
The conductive layer acts as an intermediary element that bridges the electrical conductivity gap between the high-resistance pressure sensing layers and the low-resistance driving/sensing electrodes. This mediator layer ensures reliable electrical connections while maintaining the pressure sensitivity of the sensing layers.
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 enhances sensitivity and reduces manufacturing costs by adjusting the resistance variations of the pressure sensing cells, allowing for accurate pressure detection and improved electrical characteristics.
Implementation Method 1
A resistance value sensed by the pressure sensor differs depending on a force with which a user presses the pressure sensor. For example, when the force with which the user presses the pressure sensor is low, the resistance value sensed by the pressure sensor is relatively high, whereas when the force with which the user presses the pressure sensor is high, the resistance value sensed by the pressure sensor is relatively low.
Data Source
AI summary
A pressure sensor includes a first substrate and a second substrate; a first driving electrode and a second driving electrode disposed on a first surface of the first substrate facing the second substrate and coupled to a first coupling electrode, the second driving electrode being shorter than the first driving electrode; a first sensing electrode and a second sensing electrode disposed on the first surface of the first substrate and coupled to a second coupling electrode, the second sensing electrode being shorter than the first sensing electrode; a first pressure sensing layer disposed on a first surface of the second substrate in a position facing the first substrate and overlapping and spaced from the first driving electrode and the first sensing electrode by a gap; and a second pressure sensing layer contacting with the second driving electrode and the second sensing electrode and electrically coupling the second driving electrode and the second sensing electrode to each other.