Touch Driving Device Floating Display Electrodes Parasitic Capacitance
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Solution Overview
Problem
The increasing parasitic capacitance between touch sensors and display electrodes in display devices leads to degraded uplink signal waveforms and increased RC time constants, which hinder effective communication with active pens, and existing solutions that increase driving voltage result in higher power consumption.
Innovation Solution
A touch-driving device that transmits uplink signals to active pens by floating display electrodes during specific time intervals, such as VBlank or HBlank periods, and receives downlink signals in non-overlapping intervals, minimizing the effect of parasitic capacitance without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If display panels are made thinner, then the portability and design quality are improved, but parasitic capacitance between touch sensor and display electrodes increases
Solution Approach 1:
The patent segments the time domain into distinct intervals: a first time interval for transmitting uplink signals with floating display electrodes, and a second time interval for receiving downlink signals with connected display electrodes. This temporal segmentation allows the system to enjoy both the thin panel design benefits and the low parasitic capacitance performance when needed.
Solution Approach 2:
The patent dynamically switches the connection state of display electrodes between floating and connected states based on the operational phase. During uplink transmission, electrodes are dynamically floated to minimize parasitic capacitance effects, while during downlink reception, electrodes are dynamically connected to maintain display functionality.
2Reliability
If driving voltage of uplink signal is increased, then the signal waveform quality is improved, but power consumption increases
Solution Approach 1:
The patent changes the electrical state parameter of display electrodes from connected to floating during uplink transmission. This parameter change reduces parasitic capacitance effects, improving signal waveform quality without requiring increased driving voltage, thereby avoiding additional power consumption.
Solution Approach 2:
The patent implements periodic switching between floating and connected states of display electrodes in synchronization with the communication protocol. During uplink periods, electrodes are floated to improve signal quality; during downlink periods, electrodes are connected. This periodic action maintains signal integrity while minimizing overall power consumption.
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
This approach improves the characteristics of uplink signals transmitted to active pens by reducing the impact of parasitic capacitance, ensuring reliable communication without increasing power consumption.
Implementation Method 1
parasitic capacitance between a touch sensor and display electrodes
Data Source
AI summary
A display device is configured to float a display electrode coupled to a touch sensor by parasitic capacitance when an uplink signal is transmitted to a touch pen through the touch sensor.