JP2017020925A - Communication device and electronic clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sensitivity of an antenna while ensuring a degree of freedom in design in an electronic timepiece. An electronic clock 1 includes a windshield glass 2 that deflects and concentrates ultra-high frequencies, millimeter waves, and microwaves, and an antenna 3 that transmits and receives the ultra-high frequencies, millimeter waves, and microwaves. It is arranged in a range where ultra-high frequencies, millimeter waves and microwaves pass through the windshield 2 and are concentrated. [Selection diagram] Fig. 1

Description

  The present invention relates to a communication device and an electronic timepiece having a built-in antenna.

  2. Description of the Related Art In recent years, electronic wristwatches are known as portable devices with a built-in antenna that can receive satellite signals of ultra-high frequencies transmitted from GPS (Global Positioning System) satellites and can measure the current position and current time. This electronic wristwatch includes a clock unit for measuring time and an antenna for receiving a satellite signal of ultra high frequency. This antenna is composed of a patch antenna that receives a circularly polarized ultra high frequency wave.

  Patent Document 1 describes an example of such an electronic wristwatch. As a means for solving the abstract of Patent Document 1, the wrist device 1 that is a portable device with a built-in antenna is attached to the exterior case 2 having an opening at least on the surface side, the glass 13 that closes the opening, and the surface of the exterior case 2. And a metal bezel 16 disposed around the glass 13 and an antenna 30 disposed in the space inside the outer case 2. The antenna 30 has a maximum radiation direction R1 that is the thickness of the outer case 2. It is a planar antenna that is arranged in a direction that intersects the vertical direction A1 and faces the outside of the bezel 16 ”.

Japanese Patent Laying-Open No. 2015-81825

  Electronic wristwatches are strongly required to be miniaturized in order to improve their merchantability, and are required to be freely designed. If the electronic wristwatch is downsized, the antenna mounted on the electronic wristwatch must be made smaller, which may reduce the sensitivity of the antenna. In addition, since the antenna must be arranged so as to avoid loss of metal or the like and circuit noise, the mounting place is limited, and there is a possibility that the electronic wristwatch cannot be freely designed.

Patent Document 1 discloses a configuration in which an antenna is arranged so that a radio wave shield in a device does not overlap with a maximum radiation direction. However, although this configuration can contribute to improving the reception sensitivity, there is a problem that the arrangement of antennas is limited and the degree of design freedom is reduced.
Therefore, an object of the present invention is to improve the sensitivity of an antenna while ensuring a degree of freedom in designing a communication device and an electronic timepiece.

In order to achieve the above object, the present invention
Glass that refracts and concentrates radio waves in a predetermined frequency band,
An antenna for communicating radio waves in the predetermined frequency band,
The antenna is disposed in a range where radio waves in the predetermined frequency band are concentrated through the glass,
It is a communication apparatus characterized by this.

  According to the present invention, it is possible to improve the sensitivity of an antenna while ensuring a degree of freedom in design.

It is a figure which shows the structure and operation | movement of an electronic timepiece in 1st Embodiment. It is a figure which shows the case where there is no path difference of electromagnetic waves, and the case where there exists a path difference, respectively. It is a figure which shows the concentration range of the electromagnetic wave of the electronic timepiece of 1st Embodiment. It is a figure which shows an example of a radio wave lens. It is a figure which shows the structure and operation | movement of an electronic timepiece in 2nd Embodiment. It is a figure which shows the structure and operation | movement of the electronic timepiece of a comparative example.

Hereinafter, a comparative example and a mode for carrying out the present invention will be described in detail with reference to the drawings.
(Comparative example)
6A and 6B are diagrams showing the configuration and operation of an electronic timepiece 1B of a comparative example.
FIG. 6A is a cross-sectional view of the electronic timepiece 1B.
The electronic timepiece 1 </ b> B includes a metal main body case 63 formed in a hollow short column shape, and a timepiece module 7, a dial plate 51, and a solar panel 52 are accommodated in the main body case 63.
A watch module 7 formed in a substantially cylindrical shape is disposed inside the main body case 63. The timepiece module 7 is a circuit in which a timepiece movement 72 (for example, a driving motor or a train wheel mechanism, not shown) for moving the second hand 41, the minute hand 42, and the hour hand 43, which are hands of the electronic timepiece 1B, and various electronic components are mounted. The substrate 71 and the antenna 3 for receiving radio waves as GPS signals are incorporated in a housing (not shown) formed of, for example, resin. The timepiece module 7 rotationally drives the hour hand 43, the minute hand 42, and the second hand 41 to display various information such as current time information.

The antenna 3 receives a very high frequency radio signal from the outside (for example, a GPS satellite). Note that the communication standard of the antenna 3 and the communicable frequency band are not limited to GPS, and those suitable for various communications performed by the electronic timepiece 1B (that is, those suitable for frequency, etc.) are appropriately applied. In particular, frequency bands such as ultra-high frequency waves, millimeter waves, and microwaves are suitable. Moreover, the antenna 3 should just be a small thing, and a kind and shape are not specifically limited.
The antenna 3 is shielded on the lower side and is configured to receive only radio waves from the upper side. The antenna 3 is electrically connected to the circuit board 71 via a connector or the like (not shown).

  On the upper surface of the dial 51, an hour hand 43, a minute hand 42, and a second hand 41 are disposed so as to be rotatable about an axis. The dial 51, the hour hand 43, the minute hand 42, and the second hand 41 are display means for displaying time information by the electronic timepiece 1B. The solar panel 52 receives light and converts it into electric power, and operates as a power source for driving the timepiece module 7 and the like.

  The main body case 63 has an opening on the front side (viewing side of the electronic timepiece 1B, upper side in FIG. 6A) and an opening on the back side of the main body case 63 (lower side in FIG. 6A). doing. A ring-shaped bezel 61 and a parting 62 on the inner periphery thereof are provided at the front side opening of the main body case 63. A disk-shaped windshield 2B made of transparent glass is attached to the bezel 61 so as to close the opening on the surface side.

The windshield 2B protects the hour hand 43, the minute hand 42, and the second hand 41, which are display means of the electronic timepiece 1B, and makes them visible to the user.
The windshield 2B is basically made of a transparent and strong material, such as sapphire glass, white plate glass, resin glass, or quartz glass, and has a large dielectric constant and a small loss. For example, the relative dielectric constant of sapphire is about 9 to 11, the relative dielectric constant of white plate glass is about 7, and about 3.8 for quartz glass. Further, the loss angle tangent tan δ is as small as about 10 ⁻³ to 10 ⁻⁴ .

  On the other hand, a back cover 64 is attached to the back side opening of the main body case 63 so as to close the back side opening. In the present embodiment, the back cover 64 is formed of a metal material such as stainless steel or titanium, and blocks radio waves from the back surface.

FIG. 6B is an explanatory diagram of a radio wave path by a cross section of the electronic timepiece 1B.
The main body case 63, the back cover 64 that closes the opening on the back surface side, and the bezel 61 fitted in the opening on the front surface side are made of metal and block electromagnetic waves. Therefore, the radio wave from the GPS satellite arrives at the antenna 3 from above the electronic timepiece 1B via the windshield 2B. Since the windshield 2B is disk-shaped, the radio waves do not converge / diverge and pass through the inner periphery of the parting 62 to reach the antenna 3.

(First embodiment)
FIG. 1A is a cross-sectional view showing the configuration of the electronic timepiece 1 in the first embodiment.
As in the comparative example, the electronic timepiece 1 includes a metal main body case 63 formed in a hollow short column shape, and a timepiece module 7, a dial plate 51, and a solar panel 52 are provided in the main body case 63. ing. A watch module 7 formed in a substantially cylindrical shape is disposed inside the main body case 63.

  A ring-like bezel 61 and a parting 62 on the inner periphery thereof are provided in the front side opening of the main body case 63. Unlike the comparative example, a convex lens-shaped windshield glass 2 formed of transparent glass is attached to the bezel 61 so as to close the opening on the surface side. That is, the windshield 2 has a thick central portion and a thin end portion. The surface of the windshield 2 is convex and has a gentle curve, whereas the back surface is flat.

FIG. 1B is a diagram illustrating the operation of the electronic timepiece 1 according to the first embodiment. Here, a state where electromagnetic waves concentrate on the antenna 3 is shown.
The inner periphery of the parting line 62 is a circle having a radius _Rf . The electromagnetic wave in the vertical direction of the electronic timepiece 1 passes through the inner periphery of the parting 62 after passing through the windshield 2. The electromagnetic wave passes through the transparent glass having a high dielectric constant at the center of the windshield 2 by a difference between the end thickness and the center thickness. Since the speed of the electromagnetic wave in the central part is slow, the closer to the central part, the longer the propagation distance is equivalent, and the phase of the signal is delayed accordingly. As a result, the electromagnetic wave is refracted and concentrated on a circle having a radius R _r at the height of the antenna 3.
In other words, the radiation pattern of the antenna 3 is narrowed, the directivity becomes sharp, and the gain can be increased.

FIG. 2A is an explanatory diagram illustrating the path of the electromagnetic wave W when there is no path difference, and FIG. 2B is an explanatory diagram illustrating the path of the electromagnetic wave W when there is a path difference.
The electromagnetic wave W in FIG. 2A reaches the antenna 3 as a parallel path. In contrast, the electromagnetic wave W in FIG. 2B is refracted and concentrated on the antenna 3. The refraction of the electromagnetic wave W will be described using mathematical formulas.

The windshield 2 is a dielectric, and when radio waves pass through it, the windshield 2 is slower than being transmitted through the air by the square root of the relative permittivity of the material of the windshield 2. The manner in which dielectrics concentrate radio waves and act as lenses is explained by one idea that the speed of radio waves slows down by the square root of the dielectric constant as it passes through the medium.
Generally, the velocity C of electromagnetic waves is calculated by the following equation (1).

The velocity C ₀ of the electromagnetic wave in vacuum (≈air) is calculated by the following equation (2).

When 1 relative permeability mu _r of the medium, the speed C _B in the electromagnetic wave of the medium is calculated by the following equation (3).

That is, the velocity C _B of the electromagnetic wave in the medium is a value obtained by dividing the velocity C ₀ of the electromagnetic wave in the air by the square root of the relative dielectric constant of the medium. Therefore, the time required to pass through the same distance is the square root of the relative permittivity in the medium rather than in the air, and the root of the relative permittivity is converted to the distance in the air when the path of the electromagnetic wave is converted into the distance in the air. .
If the medium distance is a, the path difference R is calculated by the following equation (4).

Since the vibration frequency of the electromagnetic wave does not change, the position of the same phase shifts the path difference when an electromagnetic wave path difference occurs. Therefore, when there is a path difference in FIG. 2B, concentric circles corresponding to the same phase position gather in the center, and the electromagnetic wave W concentrates. Thereby, the sensitivity of the antenna 3 can be improved.
On the other hand, when there is no path difference in FIG. 2A, concentric circles corresponding to the same phase position do not overlap and the electromagnetic wave W does not concentrate.

FIG. 3 is a diagram illustrating a radio wave concentration range of the electronic timepiece 1 according to the first embodiment.
A circle having a radius _Rf shown in FIG. 3 corresponds to the inner periphery of the parting line 62 in the electronic timepiece 1 (see FIG. 1). A circle with a radius R _r indicates the concentration range of electromagnetic waves at the height of the antenna 3. That is, the electromagnetic waves in the range of the circle with the radius R _f are refracted by the windshield 2 and concentrated on the circle with the radius R _r at the height of the antenna 3. Thereby, the sensitivity of the antenna 3 is improved. Further, when the GPS satellite is positioned in the vertical direction of the electronic timepiece 1, the antenna 3 may be arranged in any circle within the radius _Rf . Therefore, the design freedom concerning the position of the antenna 3 can be ensured.

FIG. 4 is a diagram illustrating an example of a radio wave lens.
The windshield 2 in FIG. 4 is configured with a relative dielectric constant of 5, a thickness of 3 mm at the center, a thickness of 1 mm at the end, and a radius of 15 mm.
When electromagnetic waves enter from the upper surface of the windshield 2, the electromagnetic waves concentrate on a radius of 12.63 mm on a surface 7 mm away from the lower surface of the windshield 2. This is because electromagnetic waves are refracted 18.7 ° with respect to straight travel at the end of the windshield 2.
By the windshield 2, electromagnetic waves in a circle having a radius of 15 mm are concentrated in a circle having a radius of 12.63 mm. Therefore, the electromagnetic wave density in the antenna 3 increases 1.4 times. Note that the numerical values in FIG. 5 are merely for explaining the concept of operating as a lens, and are not necessarily optimal values. In the actual design, other numerical values may be adopted.

FIG. 5A is a configuration diagram of an electronic timepiece 1A according to the second embodiment.
The electronic timepiece 1A includes a metal main body case 63 formed in a hollow short column shape as in the first embodiment, and the timepiece module 7, the dial 51, and the solar panel 52 are contained in the main body case 63. Is provided. A watch module 7 formed in a substantially cylindrical shape is disposed inside the main body case 63.

  A ring-like bezel 61 and a parting 62 on the inner periphery thereof are provided in the front side opening of the main body case 63. A convex lens-shaped windshield glass 2A formed of transparent glass is attached to the bezel 61 so as to close the front-side opening. The windshield 2A has a convex surface and a concave back surface, but has a thick central portion and thin end portions as a whole. That is, the curve on the back surface is gentler than the curve on the front surface.

FIG. 5B is a diagram illustrating the operation of the electronic timepiece 1A according to the second embodiment. Here, a state where electromagnetic waves concentrate on the antenna 3 is shown.
The inner periphery of the parting line 62 is a circle having a radius _Rf . The electromagnetic wave in the vertical direction of the electronic timepiece 1A passes through the inner periphery of the parting 62 after passing through the windshield 2A. The electromagnetic wave is longer in the center by the difference between the end thickness and the center thickness, and passes through the transparent glass having a high dielectric constant. Since the speed of the electromagnetic wave in the central part is slow, it is equivalent to the propagation distance increasing as it is closer to the central part, and the phase of the signal is delayed accordingly. As a result, the electromagnetic wave is refracted and concentrated on a circle having a radius R _r at the height of the antenna 3.

(Effect of the invention)
In the first and second embodiments, since the center of the windshield glass 2, 2A, which is a dielectric located at the opening of the antenna 3, is thickened, the phase delay of the radio wave becomes larger at the center and acts as a dielectric lens. . As a result, radio waves are concentrated, and energy projected onto the antenna 2 is increased, so that there is an advantage that reception sensitivity is improved.
By changing the shape of the windshield glass 2 of the electronic timepiece 1, there is an advantage that the sensitivity can be improved without adding parts. Since the reception sensitivity of the antenna 3 is improved, there is an advantage that the antenna 3 can be made small and the watch can be configured to be small and thin.
Since the shape of the windshield 2 should just be changed according to arrangement | positioning of the antenna 3, the freedom degree of arrangement | positioning of the antenna 3 improves without sacrificing a sensitivity.

(Modification)
The present invention is not limited to the above-described embodiment, and can be modified without departing from the spirit of the present invention. For example, there are the following (a) to (g).
(A) The antenna 3 may be anything that transmits or receives a radio signal from the outside, and is not limited to reception.
(B) The present invention is not limited to an electronic timepiece, and may be applied to any communication device.
(C) The communication standard of the antenna 3 and the communicable frequency band are not limited to GPS and ultra-high frequency, and may be any suitable for various communications performed by the communication device. That is, it may be a Bluetooth (registered trademark) or Wi-Fi (registered trademark) communication standard and a frequency band in which this communication is possible.
(D) The shape of the windshield 2 is not limited to a convex lens shape that is rotationally symmetric. Even if the windshield 2 has an asymmetric shape, the windshield 2 only needs to have a thickness near the antenna 3 so that radio waves in a desired frequency band can be transmitted and concentrated on the antenna 3.
(E) The position of the antenna 3 is not limited to the central portion, and it may be disposed in a range where radio waves in a desired frequency band are transmitted through the windshield 2 and concentrated.
(F) The shape of the windshield 2 is not limited to refracting the electromagnetic wave by forming a convex lens, but the dielectric constant of the windshield 2 near the antenna may be increased to refract the electromagnetic wave.
(G) The radio wave communicated by the electronic timepiece or the like in the present invention is not limited to the ultra high frequency wave, and may be a millimeter wave or a microwave.

The invention described in the scope of claims attached to the application of this application will be added below. The item numbers of the claims described in the appendix are as set forth in the claims attached to the application of this application.
[Appendix]
<Claim 1>
Glass that refracts and concentrates radio waves in a predetermined frequency band,
An antenna for communicating radio waves in the predetermined frequency band,
The antenna is disposed in a range where radio waves in the predetermined frequency band are concentrated through the glass,
A communication device.
<Claim 2>
Glass that refracts and concentrates radio waves in a predetermined frequency band,
An antenna for transmitting and receiving radio waves in the predetermined frequency band,
The glass transmits the radio wave of the predetermined frequency band and concentrates it on the antenna.
A communication device.
<Claim 3>
The glass has a thickness in the vicinity of the antenna;
The communication device according to claim 1 or 2, wherein
<Claim 4>
The glass has a high dielectric constant in the vicinity of the antenna.
The communication device according to claim 1 or 2, wherein
<Claim 5>
The radio wave of the predetermined frequency band is one of ultra-high frequency, millimeter wave, and microwave,
The communication apparatus according to any one of claims 1 to 4, wherein the communication apparatus is characterized in that:
<Claim 6>
The radio wave in the predetermined frequency band is one of GPS, Bluetooth (registered trademark), and Wi-Fi (registered trademark).
The communication apparatus according to any one of claims 1 to 4, wherein the communication apparatus is characterized in that:
<Claim 7>
An electronic timepiece comprising the communication device according to any one of claims 1 to 6.
<Claim 8>
Glass that refracts and concentrates ultra-short waves,
An electronic timepiece having an antenna for transmitting and receiving ultra-short waves,
The antenna is disposed in a range where ultra high frequency waves concentrate through the glass,
An electronic timepiece characterized by that.
<Claim 9>
Glass that refracts and concentrates ultra-short waves,
An electronic timepiece having an antenna for transmitting and receiving ultra-short waves,
The glass transmits ultra-high frequency waves and concentrates on the antenna;
An electronic timepiece characterized by that.

1, 1A, 1B Electronic timepiece 2, 2A, 2B Windshield 3 Antenna 61 Bezel 62 Parting 63 Body case 64 Back cover 7 Clock module 71 Circuit board 72 Clock movement W Electromagnetic wave

Claims (9)

Glass that refracts and concentrates radio waves in a predetermined frequency band,
An antenna for communicating radio waves in the predetermined frequency band,
The antenna is disposed in a range where radio waves in the predetermined frequency band are concentrated through the glass,
A communication device. Glass that refracts and concentrates radio waves in a predetermined frequency band,
An antenna for transmitting and receiving radio waves in the predetermined frequency band,
The glass transmits the radio wave of the predetermined frequency band and concentrates it on the antenna.
A communication device. The glass has a thickness in the vicinity of the antenna;
The communication device according to claim 1 or 2, wherein The glass has a high dielectric constant in the vicinity of the antenna.
The communication device according to claim 1 or 2, wherein The radio wave of the predetermined frequency band is one of ultra-high frequency, millimeter wave, and microwave,
The communication apparatus according to any one of claims 1 to 4, wherein the communication apparatus is characterized in that: The radio wave in the predetermined frequency band is one of GPS, Bluetooth (registered trademark), and Wi-Fi (registered trademark).
The communication apparatus according to any one of claims 1 to 4, wherein the communication apparatus is characterized in that:   An electronic timepiece comprising the communication device according to any one of claims 1 to 6. Glass that refracts and concentrates ultra-short waves,
An electronic timepiece having an antenna for transmitting and receiving ultra-short waves,
The antenna is disposed in a range where ultra high frequency waves concentrate through the glass,
An electronic timepiece characterized by that. Glass that refracts and concentrates ultra-short waves,
An electronic timepiece having an antenna for transmitting and receiving ultra-short waves,
The glass transmits ultra-high frequency waves and concentrates on the antenna;
An electronic timepiece characterized by that.

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