Stylus Pen Touch Panel Multi-Frequency Position Detection

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Solution Overview

Problem

Current touch screens face challenges in simultaneously detecting the positions of multiple stylus pens, particularly when they are of different types, and in accurately measuring writing pressure, due to limitations in existing technologies that require time-consuming time division methods and struggle with fine calibration of variable capacitors.

Innovation Solution

A touch panel system that includes a receiver for receiving response signals from multiple objects based on different frequencies, a controller for identifying positions using all response signals and selectively focusing on specific loops, and a stylus pen with a divider for generating division signals based on writing pressure, enabling simultaneous detection of various types of stylus pens and accurate pressure measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If time division method is used to detect multiple stylus pens, then device complexity is reduced, but measurement precision and productivity deteriorate due to inability to simultaneously detect multiple pens

Engineering Contradiction:
Improvedetection system complexityVSAvoidposition detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the detection process into two distinct operations: a first scanning operation that determines positions of all contact objects using all antenna loops, and a second scanning operation that refines position determination using only the loop group corresponding to the detected object. This segmentation allows simultaneous detection of multiple stylus pens while maintaining measurement precision through selective refinement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a frequency dimension by assigning different frequencies to different types of stylus pens. This allows the system to distinguish between multiple pens simultaneously in the frequency domain, enabling parallel detection without time division and resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If all antenna loops are used for position determination, then measurement precision is improved, but processing time increases due to redundant scanning

Engineering Contradiction:
Improveposition determination accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by using only the necessary subset of antenna loops for refined position determination. After the first scanning operation identifies contact object positions using all loops, the second scanning operation uses only the specific loop group corresponding to each detected object, avoiding redundant scanning of all loops and reducing processing time while maintaining precision.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The detection process is segmented into two phases: initial comprehensive scanning using all antenna loops to identify contact objects, followed by selective refined scanning using only the relevant loop groups. This segmentation eliminates redundant processing while preserving measurement accuracy.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If variable capacitor is used for pressure measurement, then device complexity is reduced, but measurement precision deteriorates due to difficulty in fine calibration

Engineering Contradiction:
Improvepressure sensing structureVSAvoidwriting pressure accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from capacitance (which requires fine calibration) to frequency. The divider generates division signals with frequencies that directly correspond to writing pressure values, eliminating the calibration difficulties associated with variable capacitors while maintaining device simplicity and improving measurement precision.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If time division method is used to detect multiple stylus pens, then device complexity is reduced, but productivity deteriorates due to sequential detection requirement

Engineering Contradiction:
Improvedetection system structureVSAvoiddetection speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent transitions from time-sequential detection to parallel detection by utilizing the frequency dimension. Different stylus pen types transmit at different frequencies, allowing the receiver to simultaneously detect and distinguish multiple pens without time division, thereby improving productivity while maintaining manageable system complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The detection process is segmented into parallel operations: the receiver simultaneously receives response signals from multiple stylus pens at different frequencies, and the controller processes these signals concurrently through selective amplification and frequency-based identification, enabling multi-pen detection without sequential processing.

Inventive Principle:
Principle #1Segmentation

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

The system allows for real-time detection of multiple stylus pens regardless of type and precise measurement of writing pressure, improving user convenience and efficiency by reducing processing time and enhancing accuracy.

Implementation Method 1

a receiver 110 for receiving response signals from a plurality of objects

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a divider 220 for generating division signals divided into different frequency signals

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3245576B1Stylus pen, touch panel, and coordinate indicating system having the same
Publication Date: 2019.09.04 SAMSUNG ELECTRONICS CO LTD
  • EP3245576B1 patent drawingFigure 1~2
  • EP3245576B1 patent drawingFigure 3
  • EP3245576B1 patent drawingFigure 4

AI summary

A touch panel is provided. The touch panel includes a receiver configured to receive response signals from a plurality of objects, and a controller configured to identify positions of the plurality of objects based on different frequencies emitted from each of the plurality of objects in response to the response signals being simultaneously received through the receiver.