Piezoelectric Thin Film Transistor for Flexible Pressure Sensing
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Solution Overview
Problem
Current touch technologies face challenges in accurately detecting pressure, particularly in flexible display screens, due to limitations in sensing mechanisms and material durability.
Innovation Solution
A thin film transistor with a piezoelectric layer, separated from the active layer by insulation layers, is used to detect pressure by generating charges proportional to applied pressure, allowing for current measurement between the source and drain electrodes, and a touch apparatus comprising multiple transistors with intersecting signal lines for precise touch positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional touch sensing mechanisms are used in flexible display screens, then basic touch functionality is achieved, but pressure detection accuracy deteriorates
Solution Approach 1:
The patent replaces conventional mechanical touch sensing mechanisms with a piezoelectric-based detection system. The piezoelectric layer converts applied pressure directly into electrical signals, eliminating the need for complex mechanical sensing structures and significantly improving pressure detection accuracy while maintaining reliability in flexible display applications.
Solution Approach 2:
The patent utilizes the piezoelectric effect to change the electrical parameters (charge generation) in response to mechanical pressure. By monitoring the generated charge or current in the piezoelectric layer, the system achieves precise pressure detection through parameter transformation from mechanical to electrical domain.
2Measurement precision
If rigid piezoelectric materials are used for pressure detection, then detection precision is improved, but flexibility and durability deteriorate
Solution Approach 1:
The patent employs a piezoelectric layer in the form of a thin film or flexible structure rather than rigid bulk materials. This flexible piezoelectric layer can be integrated into flexible display screens, maintaining both detection precision and the required flexibility for bending and conforming to different surfaces.
Solution Approach 2:
The patent integrates the piezoelectric layer as part of a composite structure within the thin film transistor device, combining piezoelectric materials with flexible substrates and insulation layers. This composite approach enables simultaneous achievement of precise pressure detection and mechanical flexibility.
3Device complexity
If the piezoelectric layer is positioned close to the active layer, then device complexity is reduced, but detection sensitivity deteriorates
Solution Approach 1:
The patent introduces an insulation layer as an intermediary between the piezoelectric layer and the active layer. This insulation layer physically separates the two components, preventing direct contact and potential interference, while still allowing the piezoelectric layer to detect pressure effectively. The intermediary layer maintains detection sensitivity by ensuring proper electrical isolation while preserving mechanical coupling for pressure sensing.
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
The solution enables effective pressure detection and precise touch positioning on flexible displays, improving detection performance and durability through the use of flexible piezoelectric materials like PVDF, which are resistant to breakage and offer rapid frequency responses.
Implementation Method 1
a piezoelectric layer, separated from the active layer by the first insulation layer and separated from the source electrode and the drain electrode
Data Source
AI summary
A thin film transistor and a method for detecting a pressure by utilizing the thin film transistor, and a touch apparatus are provided. The thin film transistor includes an active layer; a source electrode and a drain electrode, separated from each other and both connected with the active layer; a first insulation layer, staked with the active layer; and a piezoelectric layer, separated from the active layer by the first insulation layer and separated from the source electrode and the drain electrode.