Display Device Protection Circuit Layout for ESD
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Solution Overview
Problem
In liquid crystal display devices, the existing configurations for preventing electrostatic discharge damage to thin film transistors are inefficient, leading to a large circuit area and potential wiring contact issues in small-sized, high-definition displays, which degrades the protection circuit function.
Innovation Solution
A display device design featuring protection circuits with diode connection type thin film transistors, a common voltage generating circuit, and a control line connected to the protection circuits, where the data lines are connected to connection wirings via protection circuits, and the control line is formed in the same layer as the common electrode, allowing for efficient electrostatic discharge protection and reduced frame area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection circuits are disposed inside of gate line driving circuit and data line driving circuit, then electrostatic discharge damage to thin film transistors is prevented, but circuit area becomes large
Solution Approach 1:
The patent extracts the protection circuit from the traditional driving circuit blocks and relocates it to the frame region. Specifically, the protection circuit is positioned between the data line driving circuit and the data lines, separating the protection function from the main driving functions. This extraction reduces the circuit area within the pixel region while maintaining electrostatic discharge protection.
Solution Approach 2:
The patent moves the protection circuit from the pixel area (2D plane within the display region) to the frame region (peripheral area). By utilizing the frame region space, the protection circuit is relocated to another dimensional space, thereby reducing the circuit area impact on the pixel region and enabling narrower frame design.
2Manufacturing precision
If wiring pitch is narrowed in small-sized high definition display, then display resolution is improved, but protection circuit wirings come into contact with each other
Solution Approach 1:
The patent segments the protection circuit into multiple components distributed across different layers. The protection circuit includes first and second protection circuits formed in different layers, with connection wirings and contact holes establishing vertical connections. This segmentation allows the protection circuit to function effectively even with narrow wiring pitch, as the multi-layer structure provides spatial separation.
Solution Approach 2:
The patent employs a multi-layer structure where protection circuit elements are nested across different layers. The first protection circuit and second protection circuit are formed in different layers, with contact holes penetrating through insulating films to connect them. This nested arrangement allows compact integration while maintaining functional separation, preventing wiring contact issues even at narrow pitches.
3Area of stationary object
If frame area is reduced, then display device size is minimized, but protection circuit area becomes insufficient
Solution Approach 1:
The patent utilizes the frame region (peripheral area) to house the protection circuit, transitioning from using pixel area to using frame area. This dimensional relocation allows the protection circuit to be positioned in the frame region between the data line driving circuit and the data lines, enabling compact display design with reduced frame area while maintaining protection functionality.
Solution Approach 2:
The patent employs a flexible multi-layer wiring structure with contact holes that can adapt to narrow spacing. The connection wirings and contact holes are designed to accommodate dynamic adjustments in wiring pitch, allowing the protection circuit to function reliably even when frame area is minimized and wiring spacing is reduced.
Data Source
AI summary
On a first substrate for a display device, gate lines, data lines, pixel electrodes, a common electrode, thin film transistors, connection wirings that correspond to the data lines, respectively, and are connected to a data line driving circuit, protection circuits, and a control line connected to the protection circuits are formed. The data lines are electrically connected to the connection wirings via the protection circuits. The connection wirings are formed in the same layer as the gate lines. The control lines is formed of the same material as that of the common electrode, and then, receives a common voltage.