Sensor Device EMI Reduction via Offset Signal Phase Inversion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In display devices with sensor systems, driving signals can act as noise, degrading display quality, while image signals can interfere with sensing sensitivity, leading to electromagnetic interference (EMI) that is difficult to mitigate without changing the frequency band of the driving signal.

Innovation Solution

A sensor device design that includes first and second sensors forming capacitance, with a sensor driver transmitting driving signals and offset signals of different phases and voltage levels through distinct sensor lines, allowing for EMI reduction without altering the frequency band of the driving signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If driving signals are transmitted to sensors, then sensing function is enabled, but electromagnetic interference occurs degrading display quality

Engineering Contradiction:

Improvesensing functionVSAvoidelectromagnetic interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the 'Blessing in disguise' principle by transmitting offset signals that are intentionally designed to match the frequency of driving signals but have inverted phases. These offset signals, which could be considered harmful noise, are actually used beneficially to cancel out the electromagnetic interference generated by the driving signals through destructive interference, thereby improving display quality while maintaining sensing function.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements 'Preliminary anti-action' by pre-transmitting offset signals to sensors before or during the transmission of driving signals. These offset signals are specifically designed with inverted phases to counteract the electromagnetic interference that will be generated by the subsequent driving signals, thereby preventing the harmful effects before they occur.

Inventive Principle:

Principle #9Preliminary anti-action

2Illumination intensity

If display signals are transmitted, then image display is enabled, but sensing sensitivity is reduced due to electromagnetic interference

Engineering Contradiction:

Improvedisplay qualityVSAvoidsensing sensitivity

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful electromagnetic interference from display signals into a beneficial effect by using offset signals with inverted phases. These offset signals cancel out the interference through destructive interference, thereby protecting sensing sensitivity while allowing full-color image display without degradation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If frequency band of driving signal is changed, then electromagnetic interference is reduced, but available frequency bands are limited

Engineering Contradiction:

Improveelectromagnetic interferenceVSAvoidfrequency band selection

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent applies 'Parameter changes' by modifying the phase parameter of the offset signals rather than changing the frequency band of driving signals. The offset signals are designed with inverted phases (180 degrees out of phase) relative to the driving signals, which changes the electromagnetic field characteristics to achieve interference cancellation while maintaining the same frequency band, thus avoiding the limitation of available frequency bands.

Inventive Principle:

Principle #35Parameter changes

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 effectively minimizes electromagnetic interference, enhancing both display quality and sensing sensitivity without requiring a change in the frequency band of the driving signal, thereby improving overall performance.

Implementation Method 1

second sensors which forms a capacitance with the first sensors

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12032787B2Sensor device

Publication Date: 2024.07.09 SAMSUNG DISPLAY CO LTD

AI summary

A sensor device includes: first sensors; second sensors which forms a capacitance with the first sensors; and a sensor driver which transmits driving signals to the first sensors through first sensor lines, and receives sensing signals from the second sensors through second sensor lines. The sensor driver sequentially transmits the driving signals to the first sensors, and transmits, during each period of transmitting the driving signals, an offset signal, which is identical in frequency to and different in phase from the driving signals, to at least one selected from first sensors which does not receive the driving signals among the first sensor. The sensor driver sets at least one selected from a slew rate and a voltage level of the offset signal to a value different from a corresponding value of a corresponding driving signal.