Internal Patch Antenna in Metal Timepiece Case
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Solution Overview
Problem
Timepieces with internal patch antennas face challenges in maintaining reception performance when the case is made of conductive materials, as the antenna's proximity to metal cases leads to signal interference and reduced reception quality, while also compromising on appearance due to the need for a non-metallic bezel to prevent performance drops.
Innovation Solution
The patch antenna is separated by a specific distance from the inside surface of the case, allowing for improved reception performance even with a metal case, and enabling a larger portion of the timepiece to be made of metal for better appearance, while also accommodating the drive staffs and wheels between the antenna and the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the patch antenna is disposed close to the face side of the timepiece to receive RF signals through the face side, then reception performance is improved, but the antenna must be offset from the plane center and disposed adjacent to the case, which causes signal reception to be easily affected by metal cases
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement where the antenna is offset toward the 12:00 position to a three-dimensional spatial solution by extending the bezel downward to cover the antenna. This vertical dimension coverage isolates the antenna from the harmful effect of the metal case while maintaining the antenna's position for optimal signal reception through the face side.
Solution Approach 2:
The bezel acts as an intermediary element between the metal case and the patch antenna. By extending the bezel to cover the antenna, it creates a protective barrier that prevents direct interaction between the metal case and the antenna, thereby eliminating signal interference while allowing the antenna to remain in its optimal reception position.
2Reliability
If a plastic bezel is extended to cover the antenna to prevent signal interference from metal case, then reception performance is maintained, but the plastic bezel occupies a large area and the quality of the timepiece appears lower
Solution Approach 1:
The patent changes the material parameter of the bezel from plastic to metal, transforming it from a non-conductive aesthetic component to a conductive functional component. This parameter change allows the bezel to serve dual purposes: maintaining structural integrity and aesthetic quality while simultaneously providing electromagnetic shielding to protect the antenna from metal case interference.
3Shape
If a metal case is used to improve the appearance of quality, then appearance quality is improved, but reception performance drops because the patch antenna is adjacent to the metal case
Solution Approach 1:
The extended metal bezel serves as an intermediary shielding structure between the metal case and the patch antenna. It creates an electromagnetic barrier that prevents the metal case from interfering with the antenna's reception performance, allowing both the metal case and metal bezel to coexist while maintaining high appearance quality and reliable signal reception.
Solution Approach 2:
The patent converts the potentially harmful effect of the metal case proximity into a beneficial shielding effect by using the metal bezel. The same metal material that causes interference when directly adjacent to the antenna is instead used to create a Faraday cage effect through the extended bezel structure, protecting the antenna while maintaining aesthetic 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 configuration ensures reliable reception of circularly polarized satellite signals, maintains desirable reception performance, and allows for a more aesthetically pleasing design by reducing the impact of the case material on antenna function and allowing for a thinner, more compact timepiece.
Implementation Method 1
a patch antenna (19) having a ceramic dielectric body (193) disposed thereon... which receives circularly polarized radio waves transmitted from a positioning information satellite
Data Source
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AI summary
A timepiece with an internal antenna, including: a case that is made from a conductive material; a movement that is housed in the case and has a plurality of motors that drive staffs disposed at a plurality of locations; a dial that is made from a nonconductive material; and a patch antenna that is disposed inside the case on the back side of the dial, receives radio signals transmitted from an external source, and includes a dielectric and an electrode formed in the dielectric; wherein the patch antenna is disposed separated at least a specific distance from the inside surface of the case, and the staffs are disposed between the case and the patch antenna.