Piezoelectric Island Touch Sensor for Pressure Detection
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Solution Overview
Problem
Current touch sensing technologies in display devices face challenges in accurately detecting touch pressure and position with high precision and efficiency, particularly in designs that require a balance between touch sensitivity and pressure detection without complex wiring or additional signal processing.
Innovation Solution
A touch sensing unit incorporating a substrate with a touch sensor and a piezoelectric area, where the piezoelectric area is arranged in an island shape and directly contacts the touch sensor, generating a voltage based on pressure applied, and includes materials like PVDF, CNT, ZnO nanowire, or lead-free piezoelectric materials, with an insulating layer and elastic layers to enhance light transmittance and pressure detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a touch sensor uses complex wiring and additional signal processing to detect touch pressure and position, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines the touch sensor and piezoelectric area into a single integrated sensing unit, eliminating the need for separate pressure sensors and complex wiring. The piezoelectric area directly contacts the touch sensor electrode, merging touch detection and pressure detection functions into one structure, thereby reducing device complexity while maintaining high measurement precision.
Solution Approach 2:
The integrated sensing unit serves multiple functions: it detects touch position through capacitance changes and simultaneously detects touch pressure through piezoelectric voltage generation. This multi-functional design eliminates the need for separate pressure sensing components and signal processing circuits, reducing overall device complexity while improving measurement precision for both position and pressure.
2Measurement precision
If the piezoelectric area uses materials with high piezoelectric effect, then pressure detection sensitivity improves, but light transmittance decreases
Solution Approach 1:
The patent changes the physical parameters of the piezoelectric area, specifically its thickness, to optimize the balance between piezoelectric effect and light transmittance. By reducing the thickness of the piezoelectric layer to a specific range (e.g., 1-10 micrometers), the material maintains sufficient piezoelectric sensitivity for accurate pressure detection while allowing adequate light transmission for display visibility.
Solution Approach 2:
The patent employs composite material structures where the piezoelectric layer is combined with transparent conductive oxide layers or other transparent materials. This composite approach enables the piezoelectric area to generate sufficient voltage for sensitive pressure detection while the transparent components maintain high light transmittance, resolving the contradiction between sensing sensitivity and optical performance.
3Measurement precision
If the piezoelectric area is made larger to improve pressure detection, then measurement precision improves, but the area available for other components decreases
Solution Approach 1:
The patent segments the sensing area into distinct functional zones: a touch sensor electrode region for position detection and a piezoelectric area for pressure detection. This segmentation allows each zone to be optimized for its specific function while sharing the same physical space, enabling accurate pressure detection without significantly increasing the overall device footprint and leaving area available for other components.
Solution Approach 2:
The patent transitions from a two-dimensional touch sensor to a three-dimensional integrated structure by stacking the piezoelectric area over the touch sensor electrode. This vertical arrangement allows the piezoelectric area to be sufficiently large for accurate pressure detection while occupying the vertical dimension rather than consuming additional horizontal space, thereby preserving area for other components.
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 allows for precise detection of touch position and pressure magnitude with reduced data processing, enabling faster and more accurate touch sensing while maintaining high light transmittance and efficient pressure detection without the need for additional signal correction.
Implementation Method 1
a piezoelectric area overlapping the touch sensor and arranged in an island shape... a touch sensor controller to receive a voltage from the piezoelectric area when the piezoelectric area receives pressure
Data Source
AI summary
A touch sensing unit includes a touch sensor, a sensor line, a piezoelectric area, and a touch sensor controller. The touch sensor is arranged in an island shape. The sensor line is connected to the touch sensor. The piezoelectric area overlaps the touch sensor and is arranged in an island shape. The touch sensor controller receives a voltage from the piezoelectric area when the piezoelectric area receives pressure and determines a magnitude of the pressure based on the voltage.