Array Substrate Transistor Configuration for Display Stability
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Solution Overview
Problem
In OLED displays, the presence of hydrogen atoms from PIN-type photodiodes can drift the threshold voltage of drive transistors, leading to non-uniform display luminance due to high leakage currents in detection switch transistors, affecting the accuracy of light detection and overall display effect.
Innovation Solution
The use of low temperature poly-si thin film transistors as drive transistors and metal oxide transistors as detection switch transistors in the pixel circuit, along with a photo detection circuit, to stabilize the drive current and reduce leakage currents, thereby improving display stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metal oxide transistors are used as detection switch transistors, then leakage current is reduced and detection accuracy is improved, but device complexity increases due to multiple transistor types
Solution Approach 1:
The patent applies different transistor types in different locations within the pixel circuit. Metal oxide transistors are specifically used for detection switch transistors where low leakage current is critical for accurate light detection, while other transistors may use different materials optimized for their specific functions. This local differentiation resolves the contradiction by placing high-performance components only where needed.
2Stability of the object's composition
If low temperature poly-si thin film transistors are used as drive transistors, then drive current stability is improved, but manufacturing complexity increases compared to simple transistor structures
Solution Approach 1:
The patent changes the material parameter of the drive transistor from conventional materials to low temperature poly-si thin film material. This material parameter change provides superior electrical stability and lower leakage current for the drive transistor, resolving the contradiction between stability and manufacturing ease by selecting a material that balances both requirements through its unique properties.
3Measurement precision
If PIN-type photodiodes are used for photo detection, then detection sensitivity is improved, but hydrogen atoms from photodiodes drift and cause threshold voltage instability in drive transistors
Solution Approach 1:
The patent extracts and separates the photo detection function into a dedicated PIN-type photodiode circuit that is electrically isolated from the drive transistor circuit. By taking out the photodetection function and implementing it through a separate detection circuit with metal oxide transistors, the harmful hydrogen atom drift effect is prevented from affecting the drive transistor threshold voltage, thus resolving the contradiction between detection sensitivity and threshold voltage stability.
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 enhances the stability of the drive current and reduces leakage currents, resulting in improved display uniformity and accuracy by avoiding the influence of hydrogen atoms and minimizing light detection errors.
Implementation Method 1
a photo detection circuit, including a detection switch transistor and a PIN-type photodiode
Implementation Method 2
a pixel circuit, including a drive transistor for driving the electroluminescent component to emit light, wherein the drive transistor is a low temperature poly-si thin film transistor
Implementation Method 3
a photo detection circuit, including a detection switch transistor and a PIN-type photodiode, wherein the detection switch transistor is a metal oxide transistor
Implementation Method 4
an electroluminescent component; a pixel circuit, including a drive transistor for driving the electroluminescent component to emit light
Data Source
AI summary
The embodiment of the present disclosure discloses an array substrate, a fabrication method thereof, and a display device. The array substrate includes: a base substrate and a plurality of pixel units on the base substrate, wherein the pixel unit includes a plurality of sub-pixels; and the sub-pixel includes an electroluminescent component, a pixel circuit and a photo detection circuit; the pixel circuit includes a drive transistor for driving the electroluminescent component to emit light, and the drive transistor is a low temperature poly-si thin film transistor; and the photo detection circuit includes a detection switch transistor and a PIN-type photodiode, and the detection switch transistor is a metal oxide transistor.