Signal Line Switching Circuit Layout for Display Back-Gate Reliability
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Solution Overview
Problem
In display devices with a light shielding layer as a back gate, there are challenges in preventing disconnections and maintaining capacitance due to the overlap of the light shielding layer with signal lines, which can lead to reliability issues.
Innovation Solution
The light shielding layer is extended to overlap with the gate electrode, forming an extension part that is electrically connected, allowing the contact part to be placed in an area without signal lines, thereby preventing disconnections and maintaining capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light shielding layer is positioned to overlap with multiple signal lines, then the transistor can be effectively controlled, but disconnections may occur and reliability deteriorates
Solution Approach 1:
The contact part is extracted from the area where signal lines are present and relocated to an area without signal lines. This separation removes the harmful interaction between the contact part and signal lines, eliminating the disconnection risk while maintaining the light shielding layer's control function over the transistor.
Solution Approach 2:
The light shielding layer is extended in the first direction beyond the gate electrode's extension, creating an extension part that contacts the gate electrode in a different spatial arrangement. This dimensional extension allows the contact to occur in an area free from signal line interference.
2Reliability
If the contact part is positioned where signal lines are present, then electrical connection is achieved, but capacitance is reduced and transistor characteristics deteriorate
Solution Approach 1:
The contact part is extracted from the signal line area and positioned in an area without signal lines. This extraction eliminates the harmful capacitance reduction effect caused by signal line proximity, thereby maintaining proper transistor capacitance characteristics.
3Reliability
If the light shielding layer is extended to form an extension part, then the contact part can be positioned in an area without signal lines, but the structure becomes more complex
Solution Approach 1:
The light shielding layer is merged with the gate electrode structure by extending it to form an extension part that is electrically connected to the gate electrode. This merging approach integrates the light shielding function with the gate control function, achieving disconnection prevention without adding separate structural elements.
Data Source
AI summary
According to one embodiment, a display device includes signal lines, and a signal line switching circuit connected to the signal lines. The signal line switching circuit includes a plural first lines each extending in a first direction and disposed at intervals in a second direction, a plural transistors apart from the first lines in the second direction and arranged in the first direction, each transistor including a gate electrode and a light shielding layer disposed to overlap with the gate electrode, and a plural second lines connecting the transistors to the first lines. The light shielding layer includes an extension part extending to an area where the first line does not exist, and is electrically connected to the gate electrode.