Display Device Wiring for ESD Resistance and Yield
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Solution Overview
Problem
Display devices manufactured using insulating substrates, such as large glass substrates, often experience reduced yield due to electrostatic discharge (ESD) leading to transistor or capacitor breakdown, with electric charges accumulating in wiring, causing reliability issues.
Innovation Solution
A display device structure incorporating a substrate, display portion, connection terminals, and specific wiring configurations where the second wiring has a higher resistance than the first wiring, and is exposed at the substrate's end portion, with a metal oxide semiconductor layer and gate electrode, to enhance ESD resistance and manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a display device is manufactured using an insulating substrate such as a large glass substrate, then the display device can be produced with large area and flexible structure, but electric charge accumulates in wiring leading to reduced yield and reliability
Solution Approach 1:
The patent extracts the harmful function of wiring by introducing a second wiring that is electrically disconnected from the first wiring. This second wiring serves as a dedicated path to ground, separating the charge dissipation function from the signal transmission function of the first wiring, thereby preventing charge accumulation that would otherwise reduce manufacturing yield
Solution Approach 2:
The second wiring acts as an intermediary element between the first wiring and ground. It provides a controlled discharge path for electrostatic charge while maintaining electrical isolation from the signal-carrying first wiring, thus mediating between the need for large substrate area and the requirement for reliable charge management
2Reliability
If the second wiring has lower resistance to improve electrical connection, then electrical noise increases and ESD protection decreases, but if the second wiring has higher resistance then ESD resistance improves
Solution Approach 1:
The patent applies local quality by making the second wiring have different resistance characteristics than the first wiring. Specifically, the second wiring has higher resistance than the first wiring, which is optimized for its specific function of providing ESD protection paths rather than efficient signal transmission. This localized resistance differentiation allows each wiring to be optimized for its particular function
3Reliability
If connection terminals are isolated to prevent ESD, then manufacturing yield improves, but device complexity increases
Solution Approach 1:
The patent merges the ESD protection function with the existing wiring structure by introducing a second wiring that is integrated into the same substrate and fabrication process as the first wiring. Both wirings are formed using the same metal oxide semiconductor layer and gate electrode structure, allowing ESD protection to be achieved without adding significant structural complexity or requiring separate fabrication steps
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
The proposed solution improves the manufacturing yield and ESD resistance of display devices, providing a high-reliability structure by isolating connection terminals and using a metal oxide semiconductor layer to reduce electrical noise and prevent short-circuits.
Implementation Method 1
The second wiring is positioned between the connection terminal and an end portion of the substrate, and includes a portion in which a side surface is exposed at an end portion of the substrate. The semiconductor layer and the second wiring include a metal oxide.
Data Source
AI summary
The manufacturing yield of a display device is improved. The resistance of a display device to ESD is increased. The display device includes a substrate, a display portion, a connection terminal, a first wiring, and a second wiring. The first wiring is electrically connected to the connection terminal and includes a portion positioned between the connection terminal and the display portion. The second wiring is electrically connected to the connection terminal, is positioned between the connection terminal and an end portion of the substrate, and includes a portion in which a side surface is exposed at an end portion of the substrate. The display portion includes a transistor. The transistor includes a semiconductor layer, a gate insulating layer, and a gate electrode. The semiconductor layer and the second wiring include a metal oxide.