Amorphous Silicon Detection Capacitors for Touch Display Panels
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Solution Overview
Problem
Conventional in-cell touch display panels face issues with light-sensing element degradation due to long-time exposure to light and poor light-absorbing efficiency in low-light environments, affecting touch detection sensitivity.
Innovation Solution
The implementation of detection capacitors with amorphous silicon as the second electrode, integrated into the thin film transistor array, which uses capacitance variation to detect touch locations, and includes a design that prevents direct illumination of the semiconductor material, enhancing sensitivity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-sensing element is formed based on the structure of a amorphous silicon TFT, then the light-sensing element can be integrated into liquid crystal display panels, but the photoelectric effect of the amorphous silicon material declines gradually due to long-time exposure to light, resulting in degradation of sensing capability
Solution Approach 1:
The patent applies preliminary action by pre-forming the amorphous silicon layer and its semiconductor characteristics before the light-sensing element is actually needed for operation. The amorphous silicon layer is formed with appropriate thickness and doping characteristics in advance, so that when the light-sensing element operates, it maintains stable photoelectric effects without gradual degradation, thus extending the useful life while ensuring reliable sensing capability.
2Measurement precision
If a light-sensing element based on the structure of a PIN photodiode is used, then the light-sensing element can be integrated into display panels, but the detection sensitivity is not desirable in the environment with insufficient light due to worse light-absorbing efficiency of polycrystalline silicon
Solution Approach 1:
The patent applies parameter changes by adjusting the thickness of the amorphous silicon layer to optimize light absorption. The amorphous silicon layer is designed with a specific thickness range that enhances light-absorbing efficiency compared to conventional polycrystalline silicon, thereby improving detection sensitivity in low-light environments while maintaining integration with display panels.
3Measurement precision
If detection capacitors are integrated into the thin film transistor array, then touch detection sensitivity is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies merging by integrating the detection capacitor structure with the thin film transistor array structure. The detection capacitor is formed using the same amorphous silicon layer and manufacturing processes as the thin film transistor, combining both functions into a unified structure. This reduces overall device complexity while maintaining improved touch detection sensitivity.
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 solution improves touch detection sensitivity in both light and dark environments, extends the useful life of touch display panel components, and integrates seamlessly with existing manufacturing processes, eliminating the need for additional components and signal amplifiers, thus enhancing display quality and aperture ratio.
Implementation Method 1
a light sensing element uses a characteristic of that a semiconductor material (such as amorphous silicon) generates photo-charges after illuminated by light, and a touch location can be detected by detecting the generation of the photo-current
Data Source
AI summary
A touch display panel is provided and includes a substrate, a plurality of gate lines, a plurality of data lines, a plurality of data output lines, a plurality of thin film transistors, and a plurality of detection capacitors. The gate lines are disposed on the substrate. The data lines are disposed on the substrate. The data lines and the gate lines define a plurality of pixel regions on the substrate. The data output lines are disposed on the substrate, and each data output line is disposed next to one data line. The thin film transistors are respectively disposed in the pixel regions. Each thin film transistor is electrically connected to the corresponding gate line and the corresponding data line. The detection capacitors are respectively disposed in the pixel regions. Each detection capacitor is electrically connected to the corresponding gate line and the corresponding data line.