Array Substrate Touch Signal Routing via Light Shielding Layer
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Solution Overview
Problem
The high number of masks required in the low-temperature polysilicon process for In-Cell Touch Panels increases production costs and reduces the aperture ratio due to excessive metal layer density, limiting pixel size and increasing power consumption.
Innovation Solution
The array substrate design incorporates a touch signal line at the same layer as the scan line, connected through via holes to a light shielding layer, which acts as a bridging line between adjacent touch signal lines, reducing the need for direct metal layer transmission lines and thus decreasing metal layer density, enhancing the aperture ratio and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch signal transmission lines are directly placed on the metal layer where data lines are located, then touch signal transmission is achieved, but metal layer density becomes too large which limits pixel size and reduces aperture ratio
Solution Approach 1:
The patent introduces a dedicated touch signal line layer (first metal layer) separate from the data line layer (second metal layer), transitioning the touch signal transmission from a two-dimensional planar layout to a three-dimensional multi-layer structure. This dimensional change allows touch signal lines and data lines to coexist without occupying the same spatial resources, thereby reducing metal layer density in any single layer while maintaining reliable touch signal transmission.
2Manufacturing precision
If multiple masks are used in the low-temperature polysilicon process, then precise patterning is achieved, but production cost increases
Solution Approach 1:
The patent combines the touch signal line formation process with the existing scan line formation process by placing both on the same first metal layer using the same mask patterns. This merging of functions allows the touch signal lines to be fabricated simultaneously with the scan lines without requiring additional masks, thereby maintaining high patterning precision while reducing production costs.
3Reliability
If metal layer density is increased to accommodate all signal lines, then signal transmission is ensured, but power consumption increases
Solution Approach 1:
The patent segments the signal transmission function by creating separate dedicated layers for different signal types: the first metal layer for scan lines and touch signal lines, and the second metal layer for data lines. This segmentation reduces the overall metal layer density required in each layer, minimizing parasitic capacitance and resistance, thereby ensuring reliable signal transmission while reducing power consumption.
Data Source
AI summary
Provided are a display device and an array substrate thereof. The array substrate includes a plurality of pixel units arranged in an array, wherein each of the pixel units comprises a light shielding layer, a thin film transistor, a touch electrode, a scan line and a data line, and the scan line is disposed in a first direction, and the data line is disposed in a second direction, and the scan line crosses the data line, and the pixel unit further comprises a touch signal line, and the touch signal line is at a same layer as the scan line, and two adjacent touch signal lines in the first direction are connected with the light shielding layer, the touch signal line is connected to the light shielding layer through a first via hole, and the touch signal line is connected to the touch electrode through a second via hole.