Thin Film Transistor Array Substrate with Integrated Photo Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ambient light sensing technologies in flat panel displays, such as p-i-n photo sensors formed through low temperature poly-silicon (LTPS) processes, suffer from poor photoelectric effects due to insufficient poly-silicon film thickness and lower sensitivity, and are affected by direct backlight irradiation, leading to distorted measurement results.
Innovation Solution
A manufacturing method for a thin film transistor array substrate with an integrated photo sensor that includes a patterned semiconductor layer, ion doping, and a silicon-rich photo sensitive dielectric layer, where the photo sensitive dielectric layer is positioned between a transparent conductive layer and a metal electrode to enhance sensing area and prevent backlight interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-i-n photo sensor is formed through LTPS process on glass substrate, then the photo sensor can be integrated in the display panel, but the photoelectric effect is poor due to insufficient poly-silicon film thickness and lower sensitivity
Solution Approach 1:
The patent changes the material parameter from poly-silicon to amorphous silicon for the photo sensor layer, which fundamentally alters the photoelectric properties. This material parameter change enables better photoelectric effect and higher sensitivity without being constrained by the thickness limitations of LTPS processes
Solution Approach 2:
The patent employs a composite structure with multiple layers including amorphous silicon photo sensor layer, silicon nitride layer, and ITO layer. This composite material approach combines the advantages of different materials to achieve superior photoelectric performance and sensitivity
2Ease of operation
If light from backlight source directly irradiates the p-i-n photo sensor through the glass substrate, then the display panel can function normally, but the photo sensing characteristics are affected and signal to noise ratio is reduced
Solution Approach 1:
The patent extracts the photo sensor function from the traditional LTPS-based implementation and relocates it to a dedicated amorphous silicon photo sensor layer with optimized optical properties. This separation allows the photo sensor to be specifically designed for ambient light detection while the display function continues independently
Solution Approach 2:
The patent introduces an intermediary ITO (indium tin oxide) layer between the photo sensor and the backlight source. This intermediary layer acts as a selective filter that allows ambient light to reach the photo sensor while blocking or filtering backlight wavelengths, thereby improving signal-to-noise ratio without compromising display function
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 method significantly increases the photo sensing area and efficiency, providing more accurate measurement results by shielding the photo sensor from backlight interference and improving signal-to-noise ratio.
Implementation Method 1
a patterned photo sensitive dielectric layer is formed on the first photo sensing electrode... incident light can directly irradiate the photo sensitive dielectric layer through the transparent conductive layer
Implementation Method 2
at the other side of the photo sensitive dielectric layer may be a metal electrode so backlight source can be prevented from directly irradiating the photo sensitive dielectric layer
Implementation Method 3
ion doping is performed on the semiconductor block and the first storage electrode. A doped source region, a doped drain region, and a channel region between the doped source region and the doped drain region are formed
Data Source
AI summary
A manufacturing method of a thin film transistor array substrate is provided. In the method, a substrate having a display region and a sensing region is provided. At least a display thin film transistor is formed in the display region, a first sensing electrode is formed in the sensing region, and an inter-layer dielectric layer is disposed on the substrate, covers the display thin film transistor, and exposes the first sensing electrode. A patterned photo sensitive dielectric layer is then formed on the first sensing electrode. A patterned transparent conductive layer is subsequently formed on the substrate, wherein the patterned transparent conductive layer includes a pixel electrode coupled to the corresponding display thin film transistor and includes a second sensing electrode located on the patterned photo sensitive dielectric layer. A manufacturing method of a liquid crystal display panel adopting the aforementioned thin film transistor array substrate is also provided.