Flexible PCB Protrusion for ESD Protection
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Solution Overview
Problem
Flexible printed circuit boards generate electromagnetic interference (EMI) and electrostatic discharge (ESD), which adversely affect OLED devices during manufacturing and operation, especially along the sides of the display panel.
Innovation Solution
A flexible printed circuit board design featuring a protrusion with a stacked structure of metal layers and insulating layers, where static electricity is directed through a third metal layer that bypasses the circuit pattern, allowing it to be transmitted to an external device without interfering with the circuit, using a conductive material like copper or nickel for the metal layers and solder resist for passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible printed circuit board is used to electrically connect the display panel, then electrical connection is achieved, but electromagnetic interference and electrostatic discharge are generated that adversely affect the OLED device
Solution Approach 1:
The flexible printed circuit board is divided into a body portion and a protrusion portion. The protrusion portion includes an exposing hole that exposes part of the third metal layer, creating a separate path for static electricity to discharge. This segmentation allows the circuit board to perform both electrical connection and ESD protection functions simultaneously, resolving the contradiction between reliable electrical connection and harmful electromagnetic interference.
Solution Approach 2:
The protrusion portion acts as an intermediary structure between the circuit area and the external environment. By including an exposing hole that exposes the third metal layer, it provides a dedicated pathway for electrostatic discharge that is separate from the circuit traces, thereby mediating between the need for electrical connection and the need to prevent electromagnetic interference and electrostatic discharge damage to the OLED device.
2Reliability
If multiple metal layers are stacked to route static electricity, then ESD protection is improved, but device complexity increases
Solution Approach 1:
The third metal layer serves multiple functions: it acts as a ground layer for normal circuit operation and simultaneously serves as a discharge path for electrostatic electricity through the exposing hole in the protrusion portion. This multi-functionality allows the same structure to provide both electrical connection and ESD protection without adding separate complex components, thereby improving ESD protection while minimizing increases in device complexity.
Solution Approach 2:
The protrusion portion is nested within the overall flexible printed circuit board structure. The exposing hole in the protrusion portion exposes part of the third metal layer, creating a nested configuration where the discharge path is integrated within the existing multi-layer structure. This nesting approach provides ESD protection functionality without requiring a completely separate external structure, thus improving protection capability while controlling complexity.
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
Effectively mitigates EMI and ESD by routing static electricity away from the circuit pattern, reducing interference and discharge impacts on OLED devices, thereby improving their performance and manufacturing reliability.
Implementation Method 1
the first conductive layer is electrically insulated from the circuit pattern in the first area and passes static electricity to the second conductive layer, and wherein the second conductive layer passes the static electricity to the third area through a signal path that passes through the first area
Implementation Method 2
the first conductive layer is electrically insulated from the circuit pattern in the first area
Data Source
AI summary
A flexible printed circuit board including a body portion, a connector, and a protrusion. The body portion has a circuit area with a circuit pattern and a peripheral area adjacent to the circuit area. The connector is for an external device and is coupled to a first side of the body portion. The protrusion protrudes from a second side of the body portion and includes an exposed part of a metal layer.