Timing Controller Horizontal Sync Stop for LCD Noise Reduction
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Solution Overview
Problem
Liquid crystal display devices experience signal receiving sensitivity degradation and malfunctions due to electromagnetic noise generated during high-resolution and high-speed operations, particularly when a position detecting circuit is mounted nearby, as existing noise suppression methods either shield the panel, blocking position coordinate detection signals or result in video signal thinning that compromises display quality.
Innovation Solution
Implementing a horizontal synchronizing signal stop period setting mode in the timing controller to stop outputting of horizontal synchronizing signals, including the video signal strobe and vertical drive clock, for at least one to several horizontal periods during a vertical period, thereby creating noise-free periods and allowing data transmission without thinning video signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the liquid crystal panel operates at high resolution and high speed, then display performance is improved, but electromagnetic noise increases causing signal receiving sensitivity degradation
Solution Approach 1:
The patent implements periodic writing stop periods during the vertical blanking period where pixel data writing is temporarily suspended. This creates intermittent noise-free intervals that allow position detecting circuits to transmit and receive signals without electromagnetic interference, while maintaining high-resolution and high-speed display operation during the remaining periods.
2Object-affected harmful factors
If shielding is applied to suppress electromagnetic noise, then noise interference is reduced, but position coordinate detection signals are blocked
Solution Approach 1:
Instead of continuous shielding, the patent uses periodic writing stop periods to create temporary noise-free windows. During these intervals, position detecting circuits can transmit and receive coordinate detection signals without interference, while the display continues to operate at high performance during other periods.
Solution Approach 2:
The patent uses timing control signals as an intermediary mechanism to coordinate between the display writing operation and position detection communication. The control unit generates writing stop period signals that synchronize the suspension of pixel data writing with the timing of position signal transmission, enabling noise-free communication without physical shielding.
3Loss of information
If writing stop periods are implemented, then noise-free periods are created for data transmission, but display continuity is interrupted
Solution Approach 1:
The patent schedules writing stop periods during the vertical blanking period when no display output is being generated anyway. This timing choice allows noise-free communication intervals without affecting the visual continuity of the display, as the stopped writing occurs during periods that would not be visible on screen.
Solution Approach 2:
The patent maintains continuous display output by confining writing stop periods to the vertical blanking period, which is a non-display interval. This ensures that the useful display action continues uninterrupted for the viewer, while still providing periodic noise-free windows for position detection signal transmission during the blanking intervals.
Data Source
AI summary
A liquid crystal device is provided which is capable of being free from degradation of signal receiving sensitivity and/or malfunction without performing thinning-out and complementing on video signals of an electronic device having an embedded peripheral circuit to receive and transmit data. A stop period during which outputting of horizontal synchronizing signal made up of a video signal strobe signal STB and vertical drive clock signal VCK is stopped at least one time or more and for two horizontal periods or more during a display period in one vertical period is set by a control device (for example, timing controller). In this horizontal synchronizing stop period setting mode processing, a first signal (for example, status signal) indicating that the outputting of the horizontal synchronizing signal is in a stop state is transmitted to an electronic circuit (for example, peripheral circuit).