Step-Down Transformer Reduces EAS Tag Deactivation Frequency

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Solution Overview

Problem

EAS deactivation equipment fails to meet increasingly stringent human exposure limits for induced fields, as existing systems generate high-frequency magnetic fields that exceed regulatory limits, and there is limited space for increasing coil inductance in mechanical housings.

Innovation Solution

Incorporating a step-down transformer between the energy storage component and deactivation coils to decrease the frequency of the decaying coil current waveform, thereby reducing induced field strength without altering the physical size of the coils or deactivation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing EAS deactivation equipment generates high-frequency magnetic fields to deactivate security tags, then deactivation performance is maintained, but human exposure limits for induced fields are exceeded

Engineering Contradiction:

Improvedeactivation performanceVSAvoidinduced field strength

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the frequency parameter of the magnetic field from high-frequency to low-frequency (below 1 kHz). This parameter change allows the system to maintain effective deactivation performance while reducing the induced field strength to comply with human exposure limits. The transformer-based frequency conversion enables this parameter transformation without compromising the fundamental deactivation mechanism.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If coil inductance is increased to reduce frequency, then induced field strength decreases, but mechanical housing space is insufficient

Engineering Contradiction:

Improveinduced field strengthVSAvoidcoil size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent introduces a transformer as an intermediary device between the power source and the deactivation coil. This transformer enables frequency conversion without requiring changes to the coil's physical dimensions or inductance. The intermediary transformer handles the frequency transformation, allowing the coil to maintain its original size while still achieving low-frequency operation that reduces induced field strength.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If deactivation frequency is reduced to meet regulatory limits, then human exposure compliance is achieved, but deactivation effectiveness may be compromised

Engineering Contradiction:

Improveinduced field strengthVSAvoiddeactivation effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent substitutes the traditional direct high-frequency generation approach with a transformer-based frequency conversion system. This substitution enables the generation of low-frequency magnetic fields that comply with regulatory limits while maintaining sufficient deactivation effectiveness. The transformer-based approach replaces the need for direct high-frequency coil operation, achieving both compliance and effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively reduces induced field strength to comply with new regulations while maintaining the effectiveness of EAS deactivation, ensuring compliance without impacting performance or requiring modifications to existing equipment.

Implementation Method 1

using a step down transformer, disposed between the energy storage component and the at least one deactivation coil, to decrease a frequency of a decaying coil current waveform representing a current flowing through the at least one deactivation coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

generating a tag deactivation field to deactivate the EAS tag, label or marker by energizing the at least one deactivation coil with current supplied from the energy storage component

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnet

Data Source

PatentUS11568726B2Systems and methods for deactivation frequency reduction using a transformer

Publication Date: 2023.01.31 SENSORMATIC ELECTRONICS CORP

AI summary

Systems and methods for deactivating an Electronic Article Surveillance (“EAS”) tag. The methods comprising: using an AC drive signal to charge an energy storage component of the tag deactivator; selectively actuating a switch so that a closed circuit is formed between the energy storage component and at least one deactivation coil of the tag deactivator; generating a tag deactivation field to deactivate the EAS tag by energizing the at least one deactivation coil with current supplied from the energy storage component; and using a step down transformer, disposed between the energy storage component and the at least one deactivation coil, to decrease a frequency of a decaying coil current waveform representing a current flowing through the at least one deactivation coil.