Segmented Conductive Watch Case Antenna Sensitivity
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Solution Overview
Problem
Conductive metal watch cases in radio-controlled wristwatches shield external radio waves and generate eddy currents, significantly reducing the receiving sensitivity of antennas due to their large size and electromagnetic loops, which are not effectively addressed by existing solutions.
Innovation Solution
The watch case is separated into multiple conductive parts, such as a watch case body and a dial ring, with insulating regions between them to prevent electromagnetic conduction and reduce eddy currents, allowing for improved antenna sensitivity even with a conductive metal housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a conductive metal watch case is used to provide luxury appearance and wearing sense, then aesthetic quality is improved, but receiving sensitivity of the antenna is degraded due to magnetic flux absorption and eddy current generation
Solution Approach 1:
The conductive watch case is divided into multiple separate conductive parts (case body, dial ring, bezel) that are electrically insulated from each other. This segmentation prevents the formation of large electromagnetic loops and reduces eddy current generation, thereby improving antenna receiving sensitivity while maintaining the luxury metal appearance.
Solution Approach 2:
Insulating members or insulating films are introduced between the separate conductive parts of the watch case. These intermediaries electrically isolate the conductive components, preventing magnetic flux absorption and eddy current formation while allowing the metal parts to maintain their aesthetic quality and structural integrity.
2Reliability
If a nonconductive synthetic resin housing is used to improve antenna receiving sensitivity, then receiving sensitivity is improved, but aesthetic quality and luxury appearance are degraded
Solution Approach 1:
The housing is designed with multiple separate conductive parts instead of a single nonconductive housing. This allows the use of metal materials for aesthetic quality while the segmentation prevents the harmful electromagnetic effects that would otherwise degrade receiving sensitivity.
Solution Approach 2:
The watch case combines multiple materials: conductive metal parts for aesthetic quality and structural strength, and insulating materials (insulating members or films) for electrical isolation. This composite structure achieves both luxury appearance and improved antenna receiving sensitivity.
3Reliability
If the watch case is separated into multiple conductive parts with insulating regions, then receiving sensitivity is improved by reducing eddy currents, but device complexity increases
Solution Approach 1:
The watch case is segmented into multiple conductive parts that are naturally separated by design (case body, dial ring, bezel). These segments are electrically isolated using thin insulating members or films, achieving reduced eddy currents without significantly increasing overall device complexity.
Solution Approach 2:
Thin insulating members or insulating films are used as intermediaries between conductive parts. These insulators are minimal in thickness and complexity, providing necessary electrical isolation while adding minimal structural complexity to the overall design.
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 configuration enhances the receiving sensitivity of the antenna by minimizing radio wave shielding and eddy current-induced energy loss, enabling reliable reception of prescribed radio waves even with a conductive metal watch case.
Implementation Method 1
an antenna 26 for receiving a standard radio wave
Implementation Method 2
a packing 46 for waterproofing the timepiece with a wireless function 10 is disposed on the upper end of the dial ring 36; the insulating region 58 is disposed on the dial plate side of the opening ends of the antenna 26
Data Source
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AI summary
[Problem] It is an object to provide a clock with a wireless function, in which the receiving sensitivity of an antenna is improved and the antenna can reliably receive a prescribed radio wave even in the case in which a watch case or the like made of a conductive metal is used. [Means for Resolution] A clock with a wireless function is provided with an antenna that is stored in a housing to receive a radio wave from the external, a watch case that configures at least a part of the housing, that has at least one portion conductive, and that is separated into a plurality of parts, and an insulating region disposed between at least two parts among the plurality of parts of the watch case to insulate the two parts one from the other.