Display Device Multiplexer Residual Voltage Noise Reduction
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Solution Overview
Problem
Display devices experience noise in touch sensing due to residual voltage levels on data lines, which affect the quality of the display and output voltage levels.
Innovation Solution
A display device incorporating an output circuit, a multiplexer, and a controller, where the multiplexer sequentially outputs data voltage to different data lines using multiplexing signals, and the controller generates control signals to switch between data voltage and a default voltage level, reducing noise by clearing residual voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data voltage is continuously supplied to data lines, then display function is maintained, but residual voltage levels cause noise in touch sensing
Solution Approach 1:
The patent applies periodic action by implementing a multiplexer that sequentially connects different data lines to the output circuit at different time periods. During non-display periods, the system periodically switches between data lines and connects a default voltage level to clear residual voltages. This periodic switching and clearing action eliminates noise accumulation while maintaining continuous display functionality, directly resolving the contradiction between maintaining display operation and preventing noise in touch sensing.
2Reliability
If multiplexer switches between data lines, then residual voltage is cleared, but switching operation complexity increases
Solution Approach 1:
The patent implements universality by designing the multiplexer to perform multiple functions: it serves as the primary data output switch for display functionality, and simultaneously acts as a switching mechanism for connecting default voltage levels during non-display periods to clear residual voltages. This multi-functional design eliminates the need for separate switching circuits, reducing overall system complexity while achieving noise reduction through periodic residual voltage clearing.
3Reliability
If default voltage level is output during non-display period, then noise is reduced, but power consumption increases
Solution Approach 1:
The patent applies partial action by implementing residual voltage clearing only during non-display periods when no data is being actively driven to the display. The multiplexer selectively switches to connect default voltage levels only when the display is not actively updating, rather than continuously. This partial operation approach reduces power consumption compared to continuous clearing, while still effectively eliminating noise during touch sensing operations.
Data Source
AI summary
A display device includes an output circuit, a multiplexer, and a controller. The output circuit is configured to output a data voltage to an output pin. The multiplexer is configured to sequentially output the data voltage to different data lines according to a first multiplexing signal and a second multiplexing signal. The controller is configured to generate a control signal according to a variation of the data voltage to make the output pin output a default voltage level different from the data voltage corresponding to the data voltage.