Array Substrate Backside Bonding Layout for Narrow-Bezel Displays
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Solution Overview
Problem
Existing display technologies face challenges in fabricating narrow frame displays due to exposed lead lines that are prone to erosion from external environments, which limits the integration of driving circuits on the frame portion.
Innovation Solution
The array substrate design includes a base substrate with unexposed lead lines connected through vias to bonding pads on the opposite side, encapsulated by multiple insulating layers, allowing for integrated driving circuits without a visible frame, thereby protecting the lead lines from air and water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin film transistor is formed using a conventional method involving multiple coating and heating processes, then the transistor structure can be created, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent combines multiple coating processes (gate electrode coating, insulating film coating, source/drain electrode coating) and heating processes (first heating at 500-700°C, second heating at 300-500°C) into a single sequential treatment using the same apparatus. This merging of processes reduces the number of apparatus transitions and simplifies the overall manufacturing workflow while maintaining the required thermal treatment steps for forming the thin film transistor structure.
Solution Approach 2:
The heating apparatus is designed to perform multiple functions: it serves as both the first heating apparatus for high-temperature treatment (500-700°C) and the second heating apparatus for low-temperature treatment (300-500°C). This multi-functional design eliminates the need for separate heating equipment for different temperature zones, reducing device complexity and improving ease of manufacture.
2Manufacturing precision
If multiple separate heating apparatuses are used for different temperature zones, then precise temperature control is achieved, but the apparatus becomes more complex and requires more transitions
Solution Approach 1:
The heating apparatus is divided into distinct heating zones with independent temperature control capabilities. The first heating zone can maintain temperatures of 500-700°C while the second heating zone maintains 300-500°C, allowing precise temperature control for different processing steps without requiring separate apparatuses. This segmentation enables precise manufacturing while keeping the apparatus structure integrated and manageable.
3Reliability
If conventional coating and heating processes are used sequentially with multiple apparatus transitions, then the thin film transistor can be formed, but the overall processing time increases
Solution Approach 1:
The patent merges the gate electrode formation process, insulating film formation, and source/drain electrode formation into a single sequential treatment within one apparatus. By combining these processes and eliminating apparatus transitions, the total processing time is reduced while maintaining the reliability of transistor formation through controlled sequential treatment at appropriate temperatures.
Data Source
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AI summary
An array substrate including a display area having a plurality of subpixels is provided. The plurality of subpixels includes a plurality of first subpixels in a display-bonding sub-area and a plurality of second subpixels in a regular display sub-area. The array substrate includes a plurality of thin film transistors on a first side of the base substrate and respectively in the plurality of subpixels. A respective one of the plurality of first subpixels includes a bonding pad on a second side of a base substrate; a lead line electrically connecting a respective one of a plurality of thin film transistors to the bonding pad; and a via extending through the base substrate. The lead line is unexposed in the array substrate. The lead line extends from the first side to the second side of the base substrate through the via, to connect to the bonding pad.