Touch Sensor with Piezoelectric Materials for Integrated Position and Pressure Detection
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Solution Overview
Problem
Conventional touch sensors embedded in liquid crystal displays can only detect touch position and require a separate pressure sensor to detect touch pressure, which is inconvenient and inefficient.
Innovation Solution
A touch sensor with driving electrodes, sensing electrodes, and piezoelectric materials at intersection points, along with a touch controller that uses AC and DC components of sensing signals to detect touch position and pressure, respectively, allowing for integrated touch position and pressure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional touch sensor is used, then the touch position can be detected, but the touch pressure cannot be detected and a separate pressure sensor is required
Solution Approach 1:
The patent combines touch position detection and touch pressure detection functions into a single integrated touch sensor structure. The sensing electrode detects both AC components (for position) and DC components (for pressure) from the same capacitive coupling between driving and sensing electrodes, eliminating the need for separate pressure sensors and reducing overall device complexity.
Solution Approach 2:
The sensing electrode is designed to perform multiple functions: detecting touch position through AC signal components and detecting touch pressure through DC signal components. This multi-functional approach allows a single sensor structure to provide comprehensive touch information without requiring additional specialized sensors.
2Measurement precision
If a separate pressure sensor is installed to detect touch pressure, then pressure detection is achieved, but the device complexity increases
Solution Approach 1:
The patent extracts the pressure detection capability from the AC signal and identifies it within the DC signal component. By analyzing the DC component of the sensing signal, the system can detect touch pressure without requiring a separate pressure sensor structure, thus maintaining measurement precision while reducing device complexity.
Solution Approach 2:
The sensing electrode acts as an intermediary that translates both position and pressure information into electrical signals. The capacitive coupling between driving and sensing electrodes serves as the mediator that enables detection of both AC (position) and DC (pressure) components from a single interaction event.
3Ease of operation
If only AC components are used for detection, then touch position can be detected, but touch pressure information is lost
Solution Approach 1:
The patent segments the sensing signal into distinct AC and DC components, where AC components carry touch position information and DC components carry touch pressure information. This signal segmentation allows the system to extract and process different types of touch data separately while maintaining complete information from the original sensing event.
Solution Approach 2:
Instead of using only the necessary AC component for position detection, the system also processes the DC component which contains additional pressure information. This partial use of signal components ensures comprehensive data collection without excessive complexity.
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
Enables the liquid crystal display to detect both touch position and pressure using existing components, enhancing user interaction without the need for additional sensors.
Implementation Method 1
a plurality of piezoelectric materials disposed between the driving electrodes and the sensing electrodes at intersection points of the driving electrodes and the sensing electrodes
Implementation Method 2
a touch controller configured to detect a touch position and a touch pressure by using sensing signals output from the sensing electrodes. The touch controller may include a touch position detector configured to detect the touch position by using alternating current (AC) components of the sensing signals; and a touch pressure detector configured to detect the touch pressure by using direct current (DC) components of the sensing signals
Data Source
AI summary
There are provided a touch sensor and a liquid crystal display including the same. A touch sensor includes a plurality of driving electrodes, a plurality of sensing electrodes intersecting the driving electrodes, a plurality of piezoelectric materials disposed between the driving electrodes and the sensing electrodes at intersection points of the driving electrodes and the sensing electrodes, and a touch controller for detecting a touch position and a touch pressure by using sensing signals output from the sensing electrodes.