Embroidered Watch Case Antenna for Lightweight RF Integration

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Solution Overview

Problem

Existing antenna arrangements for watches are vulnerable to external influences, require complex design modifications, and increase the watch's weight and construction complexity, while also affecting its reliability and aesthetics.

Innovation Solution

A two-dimensional technical embroidery method using insulating threads or natural fibers with conductive threads forms a space-saving, flexible antenna arrangement integrated into a composite watch exterior part with a solidified resin, enclosing a radio frequency integrated circuit, allowing for reliable data communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a solid single-piece mass antenna is used, then the antenna structure is simple, but the antenna is vulnerable to external influences and affects reliability

Engineering Contradiction:
Improveantenna structure complexityVSAvoidantenna reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The antenna is segmented into multiple conductive thread windings embedded within insulating material layers. This segmentation provides mechanical protection against external influences while maintaining electrical functionality, resolving the contradiction between structural simplicity and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The antenna uses composite construction with conductive threads embedded in insulating material layers (epoxy resin, polyimide, or PTFE). This composite structure protects the conductive elements from humidity, mechanical shocks, and temperature conditions while maintaining electrical conductivity, thus improving reliability without significantly increasing complexity.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If an antenna is formed from a single mass inside the watch case, then the antenna can be integrated, but it requires space inside the case and increases weight

Engineering Contradiction:
Improveconstruction complexityVSAvoidwatch casing weight
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The antenna uses thin conductive threads wound in fine coils and embedded within thin layers of insulating material. This thin-film approach minimizes the space required within the watch case while reducing the overall weight compared to bulk solid antenna structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The antenna transitions from a three-dimensional solid mass to a two-dimensional planar winding structure embedded in thin layers. This dimensional reduction allows the antenna to occupy minimal space within the watch case while maintaining its electromagnetic functionality, thus reducing both weight and spatial requirements.

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

3Ease of manufacture

If drilling is used to connect the antenna to the integrated circuit, then the connection can be made, but the assembly becomes complex and installation is difficult

Engineering Contradiction:
Improveconnection easeVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The antenna structure is merged with the watch exterior part through co-molding or co-curing processes where conductive threads are embedded within insulating material layers that form an integral part of the exterior component. This merging eliminates separate assembly steps and drilling operations, simplifying both manufacturing and installation while maintaining reliable electrical connections to the integrated circuit.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3751359B1Antenna arrangement, clock casing part comprising such an antenna arrangement and method for manufacturing such a clock casing part
Publication Date: 2024.07.24 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3751359B1 patent drawingFigure 1~3

AI summary

An antenna arrangement (6) is provided for a watch case component (2) of a timepiece. The antenna arrangement consists of a technical embroidery, which includes an embroidered structure of insulating threads or natural fibers (10) and at least one conductive thread (12) embroidered to form a fine coil integrated within said embroidered structure of insulating threads or natural fibers. The conductive thread is connected to a radio frequency integrated circuit (8).