Array Substrate Photosensitive Elements Simplify Optical Touch Fabrication
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Solution Overview
Problem
Existing optical touch screen technologies require complex fabrication processes due to the integration of photosensitive transistors in the array substrate, which complicates the manufacturing of in-cell optical touch screens.
Innovation Solution
The array substrate is designed with photosensitive elements and sensing lines formed in existing layers, including a base substrate, gate metal, semiconductor, and source-drain metal layers, allowing for simplified fabrication by integrating first and second photosensitive elements and sensing lines within these layers, and a method is provided to form these elements and lines, reducing the complexity of the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photosensitive transistors are integrated in the pixels of the liquid crystal display panel to detect external ambient light, then an in-cell optical touch screen is implemented, but the fabrication process becomes complicated
Solution Approach 1:
The photosensitive function is segmented into separate photosensitive elements that are distributed across the array substrate, with each photosensitive element corresponding to a pixel. These elements are integrated into existing layers (gate metal layer, semiconductor layer, source-drain metal layer) rather than requiring a separate photosensitive transistor structure for each pixel, thereby simplifying fabrication while maintaining touch sensing capability
Solution Approach 2:
Existing layers of the array substrate are given multiple functions: the gate metal layer serves both as a gate electrode structure and as a layer containing sensing lines; the semiconductor layer contains both transistor active regions and photosensitive elements; the source-drain metal layer contains both source/drain electrodes and additional sensing lines. This multi-functionality reduces the number of fabrication steps while achieving touch sensing
2Ease of manufacture
If photosensitive elements and sensing lines are formed in existing layers of the array substrate, then fabrication complexity is reduced, but layer integration and electrical connection requirements increase
Solution Approach 1:
The sensing lines are merged with existing conductive layers: first sensing lines are formed in the gate metal layer alongside gate electrodes, and second sensing lines are formed in the source-drain metal layer alongside source/drain electrodes. This merging approach allows the sensing function to be added without creating entirely new layers, thus simplifying fabrication while managing integration complexity
Solution Approach 2:
Photosensitive elements are nested within the existing layer structure of the array substrate. The first photosensitive elements are formed in the semiconductor layer between the gate metal layer and source-drain metal layer, utilizing the space within the existing transistor structure. This nesting approach integrates the photosensitive function without adding external layers, simplifying the overall manufacturing process
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 approach simplifies the fabrication process of the array substrate and optical touch screen, enabling more efficient production while maintaining touch sensing functionality, reducing misjudgment from ambient light changes, and allowing for accurate touch position detection.
Implementation Method 1
Each of the plurality of first photosensitive elements is configured to generate a current signal responsive to ambient light, and each of the plurality of second photosensitive elements is configured to generate a current signal responsive to ambient light
Data Source
AI summary
Disclosed is an array substrate including a base substrate and a gate metal layer, a semiconductor layer, a source-drain metal layer, and a pixel electrode layer that are formed on the base substrate. The gate metal layer includes gate lines, gate electrodes of thin film transistors, and a plurality of first sensing lines extending along a row direction. The semiconductor layer includes an active layer of the thin film transistors, and a plurality of first photosensitive elements and a plurality of second photosensitive elements that are insulated from each other. The source-drain metal layer includes data lines, source electrodes and drain electrodes of the thin film transistors, and a plurality of second sensing lines extending along a column direction. Also disclosed are a method of fabricating the array substrate, an optical touch screen and a display device.