Daisy-Chain Display Modules with End-Point EMI Noise Control
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Solution Overview
Problem
In modular display apparatuses, noise exceeds threshold values due to signal output from display modules at end points, particularly as the number of modules increases, necessitating an efficient method for controlling signal output.
Innovation Solution
A first driver IC in each display module provides driving signals sequentially to adjacent ICs and modules based on connection information, identifying and managing connections through a daisy chain method to prevent signal output from end-point modules, using a driving protocol set by a timing controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If display modules are connected in a daisy chain method to enable sequential signal transmission, then signal control efficiency is improved, but electromagnetic interference (EMI) radiation noise exceeds threshold values due to signal output from end-point modules
Solution Approach 1:
The patent applies local quality by differentiating the behavior of display modules based on their position in the daisy chain. End-point modules are configured with a specific property (not outputting driving signals) that differs from intermediate modules. This is achieved through receiving different types of signals (horizontal synchronization signal vs. video signal) based on local position, thereby reducing EMI noise from end-point modules while maintaining sequential signal transmission efficiency.
2Area of stationary object
If the number of display modules is increased to achieve larger display systems, then display size and resolution are improved, but noise significantly exceeds threshold values
Solution Approach 1:
The patent segments the display system into multiple daisy-chained modules, where each module is controlled independently based on its position. By segmenting the system and applying different signal handling rules to different segments (end-point vs. intermediate modules), the overall display size can be increased while controlling noise from each segment. The end-point modules are specifically configured not to output driving signals, preventing noise accumulation as the system scales.
3Reliability
If end-point display modules output driving signals, then signal transmission completeness is maintained, but radiation signals cause noise to exceed threshold values
Solution Approach 1:
The patent extracts the harmful function (outputting driving signals) from end-point modules while preserving the essential function in intermediate modules. End-point modules receive and process signals for display purposes but are configured not to output driving signals to the next module. This extraction of the harmful output function from end-point modules eliminates radiation signal noise while intermediate modules continue to perform complete signal transmission.
Solution Approach 2:
The patent inverts the conventional approach by having end-point modules (which would normally output signals in a standard daisy chain) instead not output signals. The inversion is achieved through the timing controller sending a horizontal synchronization signal to the end-point module, which triggers a response signal but prevents driving signal output. This inverted behavior at end-points eliminates noise while intermediate modules maintain normal signal transmission.
Data Source
AI summary
Provided is a display module including a communication interface, and a plurality of driver integrated circuits (ICs), wherein a first driver IC among the plurality of driver ICs is configured to: based on obtaining a driving signal from an external device through the communication interface, provide the driving signal to a second driver IC adjacent to the first driver IC so that the driving signal is sequentially provided to remaining driver ICs among the plurality of driver ICs, and provide, to a second display module among the plurality of display modules, the driving signal based on module connection information including whether the second display module is connected to any one display module among the plurality of display modules by a daisy chain method.