Touch Sensor Node Driving With Reverse-Polarity EMI Cancellation
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Solution Overview
Problem
Electro-magnetic interference (EMI) caused by signals applied to electrodes of touch sensor devices in electronic devices affects the reliability of operation in multimedia devices such as televisions, cellular phones, and game machines.
Innovation Solution
A sensor device with a sensor array and driver that applies a first pulse signal to a selected sensor node and a second pulse signal with reversed polarity to an adjacent node, temporarily connecting them to adjust voltage levels, thereby minimizing EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulse signal is applied to sensor nodes to sense touch, then touch sensing capability is improved, but electro-magnetic interference (EMI) increases causing degradation in reliability
Solution Approach 1:
The patent applies preliminary anti-action by introducing a compensation signal with reverse polarity before the harmful EMI can fully affect the system. The compensation signal is generated in advance and applied to adjacent sensor nodes to counteract the electromagnetic interference produced by the sensing pulse signals, thereby preventing EMI degradation before it occurs.
Solution Approach 2:
The patent converts the harmful EMI into a beneficial effect by utilizing the electromagnetic field generated by sensing signals and transforming it through a compensation signal. The same pulse signals that cause EMI are used to generate a compensating electromagnetic field with reverse polarity, turning the harmful interference into a useful counterbalancing force that improves overall system reliability.
2Measurement precision
If driving voltage is increased to improve sensing performance, then touch detection capability is improved, but electro-magnetic interference and energy consumption increase
Solution Approach 1:
The patent applies parameter changes by modifying the polarity parameter of the compensation signal to be opposite to the sensing signal. This parameter transformation allows the system to maintain effective touch detection while reducing EMI, as the reverse polarity creates a counterbalancing electromagnetic field that cancels out the harmful interference without requiring increased driving voltage.
3Area of stationary object
If signals are applied to multiple sensor nodes simultaneously, then touch sensing coverage is improved, but electro-magnetic interference increases
Solution Approach 1:
The patent merges the sensing signal and compensation signal into a unified electromagnetic field management system. By combining multiple sensing signals with their corresponding compensation signals across adjacent sensor nodes, the system achieves broad sensing coverage while the integrated compensation mechanism collectively reduces EMI throughout the entire sensor array.
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
Reduces EMI, improving the reliability of sensor device and system operations by reducing the need for driving voltage and mitigating electric fields.
Implementation Method 1
Signals and/or pulses applied to electrodes of the touch sensor device may induce electro-magnetic interference (EMI, or a noise) on components in the touch sensor device
Implementation Method 2
the sensor driver may be configured to electrically connect the first signal line and the second signal line to each other to adjust voltage levels of the first and the second pulse signals
Data Source
AI summary
A sensor device including: a sensor array including sensor nodes; signal lines connected to the sensor nodes; and a sensor driver configured to: select each of the sensor nodes through the signal lines to sense a touch of a user that is adjacent to the sensor array; apply, through a first signal line, a first pulse signal to at least one first sensor node adjacent to the selected sensor node among the sensor nodes; and apply, through a second signal line, a second pulse signal having a polarity reverse to a polarity of the first pulse signal to at least one second sensor node among the sensor nodes, wherein the sensor driver electrically connects the first signal line to the second signal line to adjust voltage levels of the first and the second pulse signals.