Display Device Shielding for EMC Noise Immunity
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Solution Overview
Problem
Display devices, particularly on-vehicle display devices, face stringent electromagnetic compatibility (EMC) requirements that existing technologies struggle to meet due to issues with electromagnetic interference (EMI) and susceptibility (EMS), especially with in-cell type touch panels and driver ICs that generate noise currents and have vulnerable signal grounds.
Innovation Solution
The display device configuration includes a conductive frame, control printed board, flexible printed board, and conductive shield cover, with strategically positioned front and back ground pads and a conductive shield cover to stabilize the signal ground, reduce noise propagation, and enhance immunity by providing a short propagation path for surge noise and attenuating external noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional display device structure is used, then the device complexity is low, but the electromagnetic compatibility (EMC) performance is poor due to noise propagation and external noise susceptibility
Solution Approach 1:
The patent implements a nested shielding structure where the conductive shield cover is disposed behind the control printed board, with the conductive frame positioned between the display panel and the control printed board. This nested arrangement of shielding components effectively reduces electromagnetic interference while maintaining a compact device structure.
Solution Approach 2:
The conductive frame acts as an intermediary element that provides both EMI shielding and a reference ground plane. It is electrically connected to both the display panel and the control printed board, serving as a mediator to reduce noise propagation and external noise susceptibility without requiring separate shielding components for each function.
2Reliability
If ground pads are strategically positioned and connected to conductive frame and shield cover, then noise immunity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent combines multiple ground connections into a unified reference ground system through the conductive frame. The front ground pad connects to the conductive frame while the backside ground pad connects to the conductive shield cover, which is itself connected to the conductive frame. This merging of ground paths simplifies the overall connection architecture and reduces the precision requirements for individual connections while maintaining effective noise immunity.
Data Source
AI summary
A display device includes a driver circuit on a display panel, a conductive frame that is disposed behind the display panel and supplies a frame ground, a control printed board disposed behind the conductive frame, and a conductive shield cover covering at least a part of the back face of the control printed board. The control printed board includes a front ground pad and a backside ground pad. The front ground pad is electrically connected to the back face of the conductive frame. The backside ground pad is electrically connected to the conductive shield cover. A part of an end of the conductive shield cover is electrically connected to the partial region.