Multi-Pen Touch Sensing via Frequency Segmentation and Filtering

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Solution Overview

Problem

Current touch display devices face challenges in simultaneously sensing multiple pens and accurately distinguishing between them while minimizing signal noise and optimizing power and bandwidth usage.

Innovation Solution

A touch display device and multi-pen sensing method that employs a touch circuit capable of recognizing multiple pens by using downlink signals with unique information, such as codes or frequencies, to distinguish between pens and manage signal transmission effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional touch sensing methods are used, then single pen sensing is achieved, but multiple pens cannot be simultaneously sensed

Engineering Contradiction:
Improvenumber of pens sensedVSAvoidmulti-pen sensing capability
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent segments the sensing process by dividing the touch panel into multiple sensing regions and using multiple sensing circuits to simultaneously detect multiple pens. Each sensing circuit handles a specific region or frequency range, enabling parallel detection of multiple pens without interference

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the frequency parameter of the sensing signal to enable multi-pen detection. By using different frequency ranges for different pens and applying frequency filtering, the system can distinguish and simultaneously sense multiple pens that would otherwise be indistinguishable in conventional single-frequency systems

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If multiple pens are sensed simultaneously, then multi-pen recognition is achieved, but signal noise increases

Engineering Contradiction:
Improvenumber of pens sensedVSAvoidsignal noise
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies frequency filtering to separate and isolate signals from multiple pens. By assigning different frequency ranges to different pens and using band-pass filters, the system maintains signal integrity and reduces noise while sensing multiple pens simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces frequency filtering as an intermediary mechanism between the multiple pen signals and the sensing circuit. This intermediary selectively passes desired frequency components while blocking noise and interference, enabling clean simultaneous detection of multiple pens

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple pens are distinguished using unique signals, then accurate pen identification is achieved, but power consumption increases

Engineering Contradiction:
Improvepen identification accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic sensing with pens activated in alternating time slots rather than continuous simultaneous sensing. This time-division approach allows accurate identification of each pen through unique frequency assignment while significantly reducing overall power consumption compared to continuous multi-pen detection

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically adjusts the sensing frequency and activation state of different pens based on their usage patterns. Active pens receive continuous attention at their assigned frequencies while inactive pens are put into low-power states, optimizing the balance between identification accuracy and power consumption

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3462291B1Touch display device, touch circuit, pen, touch system, and multi-pen sensing method
Publication Date: 2024.09.04 LG DISPLAY CO LTD
  • EP3462291B1 patent drawingFigure 1
  • EP3462291B1 patent drawingFigure 2
  • EP3462291B1 patent drawingFigure 3

AI summary

Disclosed are a touch display device (10), a touch circuit (300), a pen (Pen), a touch system, and a multi-pen sensing method for receiving downlink signals (DLS #1, ..., DLS #N) output from two or more pens (Pen #1, ..., Pen #N) through one or more touch electrodes (TE) on a panel (TSP) and distinguishably sensing the two or more pens (Pen #1, ..., Pen #N) based on unique information (UI #1, ..., UI #N) of the received downlink signals (DLS #1, ..., DLS #N).