Ceramic Key Shaft with Embedded RFID Antenna

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Solution Overview

Problem

Current RFID-based lock/key systems face challenges in contactless reading of 13.56 MHz RFID chips due to the interference from metal keys and difficulty in reading over the angular position, and existing solutions are inadequate in enhancing security against manipulation.

Innovation Solution

The key shank is made of technical ceramics with an embedded tungsten wire antenna, and the RFID chip is housed in a plastic loop, while a material query system checks the ceramic properties to ensure proper key insertion, using a hardened plate to release the tumbler mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a metal key is used with current RFID media at 13.56 MHz, then the key can be easily manufactured and handled, but the metal prevents contactless reading of the RFID chip

Engineering Contradiction:
Improvekey manufacturingVSAvoidRFID reading reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The key shaft is made of technical ceramic (non-conductive material) instead of metal, while the key bow remains plastic. This composite construction allows the RFID antenna to be embedded in the ceramic shaft, enabling contactless reading without metal interference, while maintaining ease of manufacture through standardized ceramic and plastic components

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The technical ceramic shaft acts as an intermediary between the metal key bow and the RFID chip, providing a non-conductive path that allows electromagnetic signals to pass through for contactless reading while still providing structural support and housing for the antenna

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the RFID antenna is integrated into the key bow, then the reading distance and angle are improved, but the reading antenna in the cylinder core has difficulty reading the medium over this distance/angle

Engineering Contradiction:
Improvereading distance and angleVSAvoidantenna reading capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The RFID antenna is extracted from the plastic key bow and relocated to the technical ceramic key shaft. This positioning places the antenna closer to the lock's reading antenna in the cylinder core, improving magnetic coupling and reading reliability while maintaining ease of operation through contactless reading capability

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If a plastic key shaft is used, then the key can be easily manufactured, but the material detection mechanism cannot verify ceramic properties such as hardness and smooth surface

Engineering Contradiction:
Improvekey manufacturingVSAvoidmaterial verification security
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The key consists of a plastic bow combined with a technical ceramic shaft. The ceramic shaft provides verifiable material properties (hardness, smooth surface) that the detection mechanism can verify, while the plastic bow provides ease of manufacture and housing for the RFID chip

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Only the key shaft portion that interacts with the detection mechanism (the portion inserted into the cylinder core) is made of technical ceramic with verifiable properties, while the key bow remains plastic. This localized application of ceramic material provides security verification where needed without requiring the entire key to be ceramic

Inventive Principle:
Principle #3Local quality

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 solution enables secure, contactless reading of RFID chips in metal-free ceramic keys, enhancing security and facilitating easy key insertion by verifying ceramic properties, thus improving the overall security and functionality of the lock/key system.

Implementation Method 1

a 13.56 MHz RFID chip is read contactlessly

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3131067B1Key for an electronic or mechatronic lock and key system and lock and key system for a key
Publication Date: 2021.07.14 ASSA ABLOY SICHERHEITSTECHNIK GMBH
  • EP3131067B1 patent drawingFigure 1~6

AI summary

The invention relates to a key for an electronic or mechatronic lock-key system, characterized in that the shaft of the key is made of a ceramic material and that an RFID antenna is embedded in it, which is conductively connected to an RFID chip arranged in the bow.