JP2006333183A - Antenna and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna capable of sufficiently receiving radio waves without making the entire antenna large and electronic equipment including the antenna. <P>SOLUTION: The antenna includes a rod-like core 110, a bulk configuration 110A having an end part in the longitudinal direction of the core 110 to receive radio waves, a coil 120 wound around a central portion 110B of the core in the longitudinal direction and a radio wave permeable decorative plate 5. The core 110 is disposed under the radio wave permeable decorative plate 5, and the bulk configuration 110A has such a shape to make a side of a surface C of the portion facing the decorative plate 5 receive more radio wave than a side of a surface D of the portion opposite to the facing surface in relation to an axial line X of the central portion 110B of the core 110 in the longitudinal direction when receiving the radio wave. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna and an electronic device that receive radio waves.

2. Description of the Related Art Conventionally, portable electronic devices such as wristwatches that use metal for a case, a back cover, and a dial are known. However, when a metal is used for a case or the like in an electronic device with a built-in antenna, the metal shields the radio wave, and the built-in antenna cannot sufficiently receive the radio wave.
Therefore, there are known cases where metal is used for the case and back cover, but metal is not used for the dial so that the built-in antenna can receive radio waves from the dial (for example, patents). Reference 1).
JP 2004-340700 A

However, in the antenna described in Patent Document 1, since the portion of the antenna that can receive radio waves is limited, radio waves cannot be sufficiently received from the dial side.
In addition, when the antenna is enlarged in order to obtain good reception sensitivity, a restriction is imposed on a mounting space in which other components are arranged, and it is difficult to reduce the size of the apparatus.

  The subject of this invention is providing the antenna and electronic device which can improve receiving sensitivity, without enlarging the whole antenna.

  In order to solve the above-mentioned problems, the invention described in claim 1 includes a rod-shaped core (for example, the core 110 in FIG. 3) and a bulging portion (at the end of the core in the longitudinal direction) for receiving radio waves ( For example, a bulging portion 110A in FIG. 3), a coil (for example, the coil 120 in FIG. 3) wound around a central portion in the longitudinal direction of the core (for example, the central portion 110B in FIG. 3), and radio wave transmission A decorative plate (for example, the dial plate 5 in FIG. 2), the core is disposed at a lower portion of the decorative plate, and the bulging portion is a central portion in the longitudinal direction of the core when receiving radio waves. The amount of received radio waves on the facing surface (for example, the facing surface 110C in FIG. 3) facing the decorative plate across the axis (for example, the axis X in FIG. 3) is opposite to the facing surface (for example, FIG. 3). It is characterized by having a shape that is larger than the opposite surface 110D) side.

  According to a second aspect of the present invention, in the antenna according to the first aspect (for example, the antenna 100 of FIG. 3), the bulging portion is directed from the longitudinal end portion of the core toward the decorative plate side. It is characterized by bending.

  According to a third aspect of the present invention, in the antenna according to the first aspect, the area of the facing surface of the bulging portion facing the decorative plate is larger than the cross-sectional area of the central portion in the longitudinal direction of the core. It is characterized by.

  According to a fourth aspect of the present invention, in the antenna according to the first aspect, the bulging portion has a radio wave reception area on the opposite surface side facing the decorative plate, the opposite surface side of the opposite surface across the axis. It is characterized by being larger than the radio wave reception area.

  According to a fifth aspect of the present invention, in the antenna according to the first aspect, the bulging portion is bent in a direction from a longitudinal end portion of the core toward the decorative plate, and the bulging portion The diameter of the portion is gradually reduced toward the central portion in the longitudinal direction of the core, and is characterized by being substantially constant at the central portion in the longitudinal direction of the core.

  The invention described in claim 6 is a rod-shaped core (for example, the core 310 of FIG. 9) and a coil (for example, the core) wound around the longitudinal central portion (for example, the central portion 310B of FIG. 9) of the core. 9) and a radio wave transmitting decorative plate (for example, the dial plate 5 of FIG. 8), the core is disposed at a lower portion of the decorative plate, and in the longitudinal direction of the core. A magnetic sheet (for example, magnetic sheet 310C in FIG. 9) is attached to the end (for example, end 310A in FIG. 9) so as to protrude outward from the core.

  The invention according to claim 7 is the antenna according to claim 6, wherein the magnetic sheet is made of an amorphous metal.

  According to an eighth aspect of the present invention, in the antenna according to any one of the first to seventh aspects, the core is made of a bulk amorphous metal.

The invention according to claim 9 is a radio wave non-transparent case (for example, a watch case 2 in FIG. 1) having an opening in the upper part,
A radio wave transmitting decorative plate (for example, the dial plate 5 in FIG. 2) disposed on the opening side of the case;
A rod-shaped core (for example, the core 110 in FIG. 3), a bulging portion (for example, the bulging portion 110A in FIG. 3) that is provided at an end portion in the longitudinal direction of the core and receives radio waves, and the longitudinal direction of the core An antenna (for example, the antenna 100 of FIG. 3) having a coil (for example, the coil 120 of FIG. 3) wound around the central portion (for example, the central portion 110B of FIG. 3),
The antenna is disposed at a lower portion of the decorative plate, and the bulging portion faces the decorative plate (for example, the axial line X in FIG. 3) facing the decorative plate when receiving radio waves. 3, the amount of received radio waves on the opposite surface 110 </ b> C side in FIG. 3 is larger than that on the opposite surface (for example, the opposite surface 110 </ b> D in FIG. 3) side of the opposite surface.

  According to a tenth aspect of the present invention, in the electronic device according to the ninth aspect (for example, the wristwatch 1 in FIG. 1), the bulging portion is directed from the longitudinal end portion of the core toward the decorative plate. It is characterized by bending in the direction.

  According to an eleventh aspect of the present invention, in the electronic device according to the ninth aspect, in the bulging portion, the area of the facing surface facing the decorative plate is larger than the cross-sectional area of the central portion in the longitudinal direction of the core. It is characterized by that.

  According to a twelfth aspect of the present invention, in the electronic device according to the ninth aspect, the bulge portion has a radio wave reception area on the opposite surface side facing the decoration plate, the surface opposite to the opposite surface across the axis. It is characterized by being larger than the radio wave reception area on the side.

  According to a thirteenth aspect of the present invention, in the electronic device according to the ninth aspect, the bulging portion is bent in a direction from the end portion in the longitudinal direction of the core toward the decorative plate, and the bulging portion The diameter of the protruding portion is gradually reduced toward the central portion in the longitudinal direction of the core, and is characterized by being substantially constant at the central portion in the longitudinal direction of the core.

The invention according to claim 14 is a radio wave impermeable case (for example, a watch case 2 in FIG. 7) having an opening in the upper portion,
A radio wave transmitting decorative plate (for example, the dial plate 5 in FIG. 8) disposed on the opening side of the case;
An antenna having a rod-shaped core (for example, the core 310 in FIG. 9) and a coil (for example, the coil 320 in FIG. 9) wound around the central portion in the longitudinal direction of the core (for example, the central portion 310B in FIG. 9). (For example, the antenna 300 of FIG. 9),
The antenna is disposed at a lower portion of the decorative plate, and a magnetic sheet (e.g., an end portion of the core in the longitudinal direction (e.g., an end portion 310 </ b> A in FIG. 9) protrudes outward from the core). A magnetic sheet 310C in FIG. 9 is attached.

The invention according to claim 15 is a radio wave non-transparent case (for example, a watch case 2 in FIG. 10) having an opening in the upper part,
A radio wave transmitting decorative plate (for example, the dial plate 5 in FIG. 11) disposed on the opening side of the case;
A rod-shaped core (for example, the core 410 in FIG. 12), a bulging portion (for example, the bulging portion 410A in FIG. 12) that has a longitudinal end of the core and receives radio waves, An antenna (for example, the antenna 400 of FIG. 12) having a coil (for example, the coil 420 of FIG. 12) wound around the center (for example, the central portion 410B of FIG. 12),
The antenna is disposed below the decorative plate, and a magnetic layer (for example, the magnetic sheet 5c in FIG. 12) formed on the lower surface of the decorative plate and the bulging portion are magnetically coupled. It is characterized by.

  According to a sixteenth aspect of the present invention, in the electronic device according to the fifteenth aspect, the magnetic layer is made of a magnetic sheet attached to the lower surface of the decorative plate.

  According to a seventeenth aspect of the present invention, in the electronic device according to the fourteenth or sixteenth aspect, the magnetic sheet is made of an amorphous metal.

  According to an eighteenth aspect of the present invention, in the electronic device according to any one of the ninth to seventeenth aspects, the core is made of a bulk amorphous metal.

  According to the first aspect of the present invention, the core is disposed below the decorative plate, and the bulging portion faces the decorative plate across the axis of the central portion in the longitudinal direction of the core when receiving radio waves. Because it has a shape that the amount of received radio waves at is larger than the opposite side of the opposite surface, it will be possible to receive radio waves sufficiently from the decorative plate side, and without making the entire antenna larger than the conventional antenna Reception sensitivity can be improved.

  According to the invention of claim 2, since the bulging portion is bent in the direction from the longitudinal end portion of the core toward the decorative plate side, it becomes easier to receive radio waves from the decorative plate side, The reception sensitivity can be improved over the conventional antenna without increasing the size of the entire antenna.

  According to the invention described in claim 3, since the area of the facing surface facing the decorative plate is larger than the cross-sectional area of the central portion in the longitudinal direction of the core, the bulging portion is more from the facing surface in the bulging portion. Thus, the receiving sensitivity of the antenna can be further improved.

  According to the invention of claim 4, the bulging portion receives radio waves because the radio wave reception area on the opposite surface side facing the decorative plate is larger than the radio wave reception area on the opposite surface side of the opposite surface across the axis. In this case, more radio waves can be received from the facing surface side in the bulging portion. Therefore, radio waves can be sufficiently received from the decorative plate side, and the receiving sensitivity can be improved as compared with the conventional antenna without enlarging the entire antenna.

  According to the invention described in claim 5, the bulging portion is bent in a direction from the end in the longitudinal direction of the core toward the decorative plate, and the diameter of the bulging portion is the central portion in the longitudinal direction of the core. Since it gradually becomes smaller toward the center of the core, it is almost constant at the central portion in the longitudinal direction of the core. Therefore, the opposite surface side of the bulging portion facing the decorative plate across the axis of the central portion is opposite to the opposite surface. The amount of radio waves received is greater than the surface side. Therefore, radio waves can be sufficiently received from the decorative plate side, and the receiving sensitivity can be improved as compared with the conventional antenna without enlarging the entire antenna.

  According to the sixth aspect of the present invention, since the plane of the magnetic sheet attached to the end portion in the longitudinal direction of the core can be used as the radio wave reception surface, a wider reception is possible without requiring much three-dimensional space. The area can be secured, and the reception sensitivity of the antenna can be improved.

  According to the invention described in claim 7, since the amorphous metal has high strength, the magnetic sheet can be made thin without being torn.

According to the invention described in claim 8, since the core is manufactured by molding amorphous metal into a bulk shape, the core is formed in comparison with a core formed by laminating a plurality of conventional amorphous metal thin films. Thus, an antenna having a shape suitable for the purpose can be manufactured more easily. In addition, since a thin film is not stacked unlike a conventional amorphous metal core, the number of processing steps can be reduced.
In addition, since the core made of amorphous metal formed in a bulk shape has extremely high magnetic permeability, the receiving sensitivity of the antenna can be extremely improved. In addition, since amorphous metal has high strength, the core can be formed extremely thin and the number of turns of the coil can be increased, so that the receiving sensitivity of the antenna can be improved. In addition, since the amorphous metal is not easily rusted and has good temperature stability, the lifetime of the antenna can be further prolonged.

  According to the ninth aspect of the present invention, the antenna is disposed at the lower part of the decorative plate, and the bulging portion receives the received radio wave on the side facing the decorative plate across the axis of the antenna when the radio wave is received. Because it has a shape in which the amount is larger than the opposite side of the facing surface, it can sufficiently receive radio waves from the decorative plate side, and the reception sensitivity of the built-in antenna than before without increasing the whole antenna It is possible to provide an electronic device with improved performance.

  According to the invention of claim 10, since the bulging portion is bent in the direction from the longitudinal end portion of the core toward the decorative plate side, it becomes easier to receive radio waves from the decorative plate side, It is possible to provide an electronic apparatus in which the reception sensitivity of an antenna built therein is improved without increasing the size of the entire antenna.

  According to the eleventh aspect of the present invention, the bulging portion can receive more radio waves because the area of the facing surface facing the decorative plate is larger than the cross-sectional area of the central portion in the longitudinal direction of the core. Thus, it is possible to provide an electronic device in which the reception sensitivity of the built-in antenna is further improved.

  According to the twelfth aspect of the present invention, since the bulging portion has a radio wave receiving area on the opposite surface side facing the decorative plate that is larger than a radio wave receiving area on the opposite surface side of the opposite surface across the axis, When received, more radio waves can be received from the facing surface side in the bulging portion. Therefore, it is possible to provide an electronic device that can sufficiently receive radio waves from the decorative plate side and that has improved reception sensitivity compared to a conventional antenna without increasing the size of the entire antenna.

  According to the invention described in claim 13, the bulging portion is bent in a direction from the end portion in the longitudinal direction of the core toward the decorative plate, and the diameter of the bulging portion is the center in the longitudinal direction of the core. Since it gradually becomes smaller as it goes to the center, it becomes almost constant at the center in the longitudinal direction of the core, so that the side of the facing surface that faces the decorative plate across the axis of the center in the bulging portion is closer to the facing surface. Receives more radio waves than the opposite side. Therefore, it is possible to provide an electronic device that can sufficiently receive radio waves from the decorative plate side and that has improved reception sensitivity compared to a conventional antenna without increasing the size of the entire antenna.

  According to the fourteenth aspect of the present invention, since the plane of the magnetic sheet attached to the end portion in the longitudinal direction of the core can be used as the radio wave reception surface, a wider reception can be achieved without requiring much three-dimensional space. An area can be secured. Therefore, the reception sensitivity of the antenna can be improved, and an electronic device that can receive radio waves with high sensitivity can be provided.

According to the fifteenth aspect of the present invention, radio waves can be received from the magnetic layer using the plane of the magnetic layer formed on the lower surface of the decorative plate as the radio wave receiving surface. Therefore, it is possible to efficiently receive radio waves from the decorative plate side.
In addition, since the antenna can receive radio waves by the surface of the magnetic layer having a large area, it can receive more radio waves, and can improve the reception sensitivity of the antenna, and the radio wave sensitivity. An electronic device that can receive well can be provided.

According to the sixteenth aspect of the present invention, radio waves can be received from the surface of the magnetic sheet using the magnetic sheet attached to the lower surface of the decorative plate as the radio wave receiving surface. Therefore, it is possible to efficiently receive radio waves from the decorative plate side.
In addition, since the antenna can receive radio waves by the surface of the magnetic sheet having a large area, it can receive more radio waves, and the reception sensitivity of the antenna can be improved. An electronic device that can receive data can be provided.

  According to the invention described in claim 17, since the amorphous metal has high strength, the magnetic sheet can be made thin without being torn.

According to the invention described in claim 18, since the core is manufactured by molding amorphous metal into a bulk shape, the core is formed in comparison with a core formed by laminating a plurality of conventional amorphous metal thin films. Thus, an antenna having a shape suitable for the purpose can be manufactured more easily. In addition, since a thin film is not stacked unlike a conventional amorphous metal core, the number of processing steps can be reduced.
In addition, since the core made of amorphous metal formed in a bulk shape has extremely high magnetic permeability, the receiving sensitivity of the antenna can be extremely improved. In addition, since amorphous metal has high strength, the core can be formed extremely thin and the number of turns of the coil can be increased, so that the receiving sensitivity of the antenna can be improved. In addition, since the amorphous metal is not easily rusted and has good temperature stability, the lifetime of the antenna can be further prolonged.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a plan view of a wristwatch 1 incorporating an antenna 100 according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
As shown in FIGS. 1 and 2, a wristwatch 1 as an electronic device includes a watch case 2 as a case for housing a clock timing unit 4 therein, and the watch case 2 is attached to a wrist of a user. The band member 8 is attached.

The watch case 2 has, for example, a cylindrical shape, and has openings at the top and the bottom. In the upper center of the watch case 2, a watch glass 2a is fitted through a packing 2b so as to close the upper opening, and a dial 5 as a decorative plate is placed on the lower part of the watch glass 2a. It is provided so as to be visible from the upper side. A switch 3 for instructing execution of various functions of the wristwatch 1 is provided around the watch case 2. A bezel 2f is provided on the upper outer periphery of the watch case 2, and a back cover 2c is attached to the bottom surface of the watch case 2 via a waterproof ring 2d.
The watch case 2 and the back cover 2c are formed of a radio wave-impermeable material such as metal, for example.
The dial plate 5 as a decorative plate is formed from, for example, a radio wave transmissive material such as resin.
Here, the decorative board is not limited to the dial 5 of the wristwatch 1, but refers to, for example, one that is arranged on a display unit of an electronic device or the like and has a decorative effect through vision.

  The clock timing unit 4 includes an upper housing portion 4a, a lower housing portion 4b, an analog pointer mechanism 7 for moving the hands 7b such as an hour hand and a second hand on the dial 5, an antenna 100 for receiving a standard radio wave, an analog pointer mechanism 7 and an antenna. The circuit board 6 which connects 100 and controls these is provided. Further, the lower housing portion 4 b, the upper housing portion 4 a, and the dial plate 5 have a structure in which each peripheral portion is attached to an inner frame 2 g provided on the inner peripheral surface of the watch case 2.

  The lower housing part 4b is supported by the upper part of the buffer member 2e provided in the upper part of the back cover 2c, and the circuit board 6 is arrange | positioned between the lower housing part 4b and the upper housing part 4a. In addition, a dial plate 5 is disposed on the upper surface of the upper housing portion 4a, and a frame-like member 5b is disposed on the upper peripheral portion of the dial plate 5 in contact with the lower peripheral portion of the watch glass 2a. .

  The analog pointer mechanism 7 includes a pointer shaft 7a extending upward from a shaft hole 5a formed in the dial plate 5 and pointers 7b such as an hour hand and a minute hand attached to the pointer shaft 7a. Move the hand above 5. A battery (not shown) for operating the analog pointer mechanism 7 is incorporated in the lower housing portion 4b, for example.

  The antenna 100 is supported by the upper housing portion 4a and is disposed between the lower portion of the dial plate 5 as a decorative plate and the upper portion of the lower housing portion 4b. The dial 5 is parallel to the longitudinal axis 110B (discussed below) of the core 110 (discussed below) of the antenna 100, and the bulging portion is integrally formed at the longitudinal end of the core 110. The facing surface 110 </ b> C (described later) of 110 </ b> A is disposed so as to face the dial 5.

FIG. 3 is a diagram illustrating the antenna 100 according to the first embodiment.
As shown in FIG. 3, the antenna 100 includes a magnetic core 110 and a coil 120 wound around the core 110.

The core 110 is formed into a bulk shape using an amorphous metal as a material. Here, the bulk shape means a solid shape made using a mold and a mold. That is, the core 110 is composed of a single substance made of amorphous metal. Specifically, the bulk amorphous metal is, for example, an Fe-based alloy, a Pd-based alloy, a Zr-based alloy, a Ni-based alloy, or the like, and the Fe-based alloy includes Fe-MB (M = Cr, W , Ta, Nb, Hf, Zr) type alloy, Fe—Co—RE—B (RE = Nb, Sm, Tb, Dy) type alloy and the like. More specifically, the amorphous metal has a composition such as Pd ₄₀ Cu ₃₀ Ni ₁₀ P ₂₀ or Fe ₈₁ B ₁₃ Si ₁₄ C ₂ . And when the melted alloy is processed into a bulk shape by casting, for example, the internal structure is made amorphous. More specifically, the core 110 is manufactured by, for example, melting the alloy that becomes an amorphous metal and sintering it under a pressure of 200 Mpa or higher at a temperature lower than the crystallization start temperature.

The core 110 is a long rod-like body, and a bulging portion 110A integrally formed at both ends in the longitudinal direction of the core 110 is bent in a direction from the back cover 2c toward the dial plate 5 side. Further, the bulging portion 110A has a facing surface 110C opposite to the side on which the bulging portion 110A and the end of the core 110 in the longitudinal direction are integrally formed, that is, a facing surface 110C facing the dial plate 5. It is circular. The diameter of the bulging portion 110A at the end portion in the longitudinal direction of the core 110 gradually decreases toward the central portion 110B in the longitudinal direction of the core 110, and in the central portion 110B in the longitudinal direction of the core 110, It is almost constant. Therefore, the area of the facing surface 110C of the bulging portion 110A is larger than the cross-sectional area of the central portion 110B in the longitudinal direction of the core 110. Further, across the axis X of the central portion 110B in the longitudinal direction of the core 110, the opposite surface 110D of the facing surface 110C is longer than the longitudinal length L1 of the core 110 on the facing surface 110C side facing the dial plate 5 of the core 110. The length L2 in the longitudinal direction of the core 110 on the side is shorter.
Here, since the core 110 is made of an amorphous metal, for example, even if the central portion 110B in the longitudinal direction is made thinner than the core formed of ferrite, the same or higher strength can be obtained. Specifically, for example, when the diameter of the central portion 110B in the longitudinal direction of the core made of ferrite is 1.5 mm, the diameter of the central portion 110B in the longitudinal direction of the core 110 using amorphous metal is, for example, 0.5 to 1.0 mm.
In addition, the coil 120 is wound in a layered manner in the central portion 110B of the core 110 in the longitudinal direction.

  When the antenna 100 is placed in a magnetic field (hereinafter referred to as “signal magnetic field”) using standard radio waves, the magnetic field acts on the antenna 100 as follows. Since the standard radio wave uses a long wave having a wavelength of several kilometers, the magnitude of the magnetic field component may be regarded as a parallel magnetic field that does not vary depending on the position in the antenna size range. Therefore, for the sake of simplicity, the signal magnetic field will be described below as a parallel magnetic field.

When the core 110 is placed in the signal magnetic field such that the axis of the coil 120 is parallel to the magnetic field direction, the magnetic flux (hereinafter referred to as “signal magnetic flux”) M1 due to the signal magnetic field is as shown in FIG. It concentrates on the core 110 whose relative permeability is higher than the space. As a result, the signal magnetic flux M1 and the coil 120 are linked to each other, and the magnetic flux 120 (hereinafter referred to as “generated magnetic flux”) has a direction in which the change of the signal magnetic flux M1 inside the coil 120 is prevented according to Lenz's law. ) An induced electromotive force V that generates M2 is generated.
The signal magnetic field is an alternating magnetic field, and the magnitude and direction of the signal magnetic flux M1 change periodically. Therefore, the induced electromotive force V becomes alternating current power, and the generated magnetic flux M2 follows the temporal change of the signal magnetic flux M1. And an alternating magnetic field whose size and direction change periodically.

  The induced electromotive force V generated in the coil 120 is detected by a receiving circuit (not shown) connected to the coil 120. The receiving circuit includes a tuning capacitor and a loss resistor for tuning to the frequency of a standard radio wave desired to be received (for example, 40 kHz or 60 kHz). The receiving circuit is mounted on a circuit board 6 shown in FIG. 2, for example.

Here, the bulging portion 110A at the end portion in the longitudinal direction of the core 110 is bent in a direction from the back cover 2c toward the dial plate 5 side, and the bulging portion 110A at the end portion in the longitudinal direction of the core 110. The diameter gradually decreases toward the central portion 110B in the longitudinal direction of the core 110, and becomes substantially constant at the central portion 110B in the longitudinal direction of the core 110.
The bulging portion 110 </ b> A has a facing surface 110 </ b> C opposite to the dial 5 with respect to the side on which the bulging portion 110 </ b> A and the longitudinal end of the core 110 are integrally formed. As a result, the radio wave receiving area on the facing surface 110C side facing the dial plate 5 at the bulging portions 110A and 110A at both ends in the longitudinal direction of the core 110 across the axis X of the central portion 110B in the longitudinal direction of the core 110. However, it is wider (larger) than the radio wave receiving area on the opposite surface 110D side of the facing surface 110C.
Therefore, when the antenna 100 receives radio waves, the facing surface 110C side of the core 110 facing the dial plate 5 is positioned on the opposite surface 110D side of the facing surface 110C across the axis X of the antenna 100. In comparison, the amount of received radio waves is increased.

  Further, the length L1 in the longitudinal direction on the facing surface 110C side facing the dial plate 5 of the core 110 across the axis X of the central portion 110B in the longitudinal direction of the core 110 is on the opposite surface 110D side of the facing surface 110C. Longer than the length L2 in the longitudinal direction. As a result, the receiving sensitivity on the facing surface 110C side in the longitudinal direction of the core 110 has a length L1 on the facing surface 110C side and a length L2 on the opposite surface 110D side of the facing surface 110C across the axis X of the antenna 100. It is higher than when equal.

Further, the antenna 100 has a surface opposite to the facing surface 110C on the side of the facing surface 110C facing the dial plate 5 of the bulging portion 110A bent in the direction toward the dial plate 5 across the axis X of the antenna 100. The amount of received radio waves is larger than that on the 110D side.
Further, with the axis X of the central portion 110B in the longitudinal direction of the core 110 interposed therebetween, the length L1 in the longitudinal direction on the facing surface 110C facing the dial plate 5 of the core 110 is closer to the opposite surface 110D side of the facing surface 110C. Since the length L2 in the longitudinal direction is shorter, the opposed surface 110C of the core 110 generates more magnetic flux M2 than the opposite surface 110D side of the opposed surface 110C.
Further, the generated magnetic flux M2 generated on the opposite surface 110D side of the facing surface 110C of the core 110 across the axis X of the central portion 110B in the longitudinal direction of the core 110 passes through the back cover 2c, and the eddy current flows through the back cover 2c. The eddy current loss of the signal magnetic flux M1 is generated, but the generated magnetic flux M2 on the opposite surface 110D side of the opposed surface 110C of the core 110 is suppressed to be smaller than that on the opposed surface 110C side, and thus is generated in the back cover 2c. Eddy current is suppressed, and eddy current loss of the signal magnetic flux M1 is suppressed.

  FIG. 4 is a block diagram showing the internal configuration of the wristwatch 1. Referring to FIG. 1, a wristwatch 1 includes a CPU (Central Processing Unit) 10, an input unit 20, a display unit 30, a ROM (Read Only Memory) 40, a RAM (Random Access Memory) 50, and a reception control unit. 60, a time code conversion unit 70, a timing circuit unit 80, and an oscillation circuit unit 82. Each part except for the oscillation circuit unit 82 is connected by a bus B, and the oscillation circuit unit 82 is connected to a time measuring circuit unit 80.

  The CPU 10 reads out a program stored in the ROM 40 in accordance with a predetermined timing or an operation signal input from the input unit 20 and develops it in the RAM 50. Based on the program, instructions and data for each unit constituting the wristwatch 1 are read. Perform forwarding, etc. Specifically, for example, the reception control unit 60 is controlled at predetermined time intervals to execute standard radio wave reception processing, and based on a standard time code (not shown) input from the time code conversion unit 70, the time measuring circuit unit 80 Correct the current time data counted in.

The input unit 20 is a switch 3 or the like for instructing execution of various functions of the wristwatch 1, and outputs a corresponding operation signal to the CPU 10 when these switches 3 are operated.
The display unit 30 includes the analog pointer mechanism 7 controlled by the dial plate 5 and the CPU 10 and displays the current time measured by the time measuring circuit unit 80.

The ROM 40 stores system programs and application programs for the wristwatch 1, programs and data for realizing the present embodiment, and the like.
The RAM 50 is used as a work area of the CPU 10 and temporarily stores a program read from the ROM 40, data processed by the CPU 10, and the like.

  The reception control unit 60 includes a radio wave receiving device 62. The radio wave receiving device 62 includes an antenna 100 and a receiving circuit (not shown), cuts out unnecessary frequency components of the standard radio wave received by the antenna 100, takes out the corresponding frequency signal, and uses the frequency signal corresponding to the electric signal. The signal converted into the signal is output to the time code conversion unit 70.

  The time code conversion unit 70 converts the electrical signal input from the radio wave receiver 62 into a digital signal, and generates a standard time code including data necessary for a clock function such as a standard time code, an integration code, and a day code. It outputs to CPU10.

  The clock circuit unit 80 counts the signal input from the oscillation circuit unit 82 to clock the current time, and outputs the clocked current time data to the CPU 10. The oscillation circuit unit 82 is a circuit that always outputs a clock signal having a constant frequency.

  As described above, according to the antenna 100 according to the first embodiment and the wristwatch 1 incorporating the antenna 100, the core 110 is disposed at the lower portion of the dial 5, and the bulging portion 110A is a core when receiving radio waves. The opposed surface 110C side facing the dial plate 5 across the axis X of the central portion 110B in the longitudinal direction of 110 is shaped to receive more radio waves than the opposite surface 110D side of the opposed surface 110C. Therefore, radio waves can be sufficiently received from the dial plate 5 side, and the reception sensitivity can be improved as compared with the conventional antenna without enlarging the entire antenna 100.

  More specifically, with the axis X of the central portion 110B in the longitudinal direction of the core 110 sandwiched between the bulging portions 110A and 110A on both ends of the core 110 in the longitudinal direction, Since the radio wave receiving area is wider (larger) than the radio wave receiving area on the opposite surface 110D side of the facing surface 110C, when the radio wave is received, the facing surfaces of the bulging portions 110A and 110A at both ends in the longitudinal direction of the core 110 More radio waves can be received from the 110C side. Therefore, radio waves can be sufficiently received from the dial plate 5 side, and the receiving sensitivity can be improved over the conventional antenna without increasing the size of the entire antenna 100.

  In addition, the length in the longitudinal direction on the opposite surface 110D side of the facing surface 110C of the core 110 is longer than the length L1 in the longitudinal direction on the facing surface 110C side of the core 110 across the axis X of the central portion 110B in the longitudinal direction of the core 110. Since the length L2 is short, the receiving sensitivity on the facing surface 110C side in the longitudinal direction of the core 110 is increased, and the receiving sensitivity of the antenna 100 can be further increased.

  Further, since the bulging portion 110A is bent in the direction from the longitudinal end portion of the core 110 toward the dial plate 5, it becomes easier to receive radio waves from the dial plate 5 side, and the entire antenna is enlarged. Therefore, the receiving sensitivity can be improved as compared with the conventional antenna.

  In addition, in the bulging portion 110A, the area of the facing surface 110C facing the dial plate 5 is larger than the cross-sectional area of the central portion 110B in the longitudinal direction of the core 110. As a result, more radio waves can be received from the facing surface 110C of the bulging portion 110A, and the reception sensitivity of the antenna 100 can be further improved.

  Further, the bulging portion 110A is bent in a direction from the end portion in the longitudinal direction of the core 110 toward the dial plate 5, and the diameter of the bulging portion 110A is directed to the central portion 110B in the longitudinal direction of the core 110. Since it gradually decreases as the core 110 becomes substantially constant in the central portion 110B in the longitudinal direction of the core 110, the facing surface 110C facing the dial plate 5 across the axis X of the central portion 110B in the bulging portion 110A. The amount of radio waves received is greater than the opposite surface 110D side of the facing surface 110C. Therefore, radio waves can be sufficiently received from the dial plate 5 side, and the receiving sensitivity can be improved over the conventional antenna without increasing the size of the entire antenna 100.

Since the core 110 is manufactured by molding amorphous metal into a bulk shape, the shape of the core 110 can be freely set as compared with a core formed by laminating a plurality of conventional amorphous metal thin films. It becomes easy to process, and the antenna 100 having a shape suitable for the purpose can be manufactured more easily. In addition, since a thin film is not stacked unlike a conventional amorphous metal core, the number of processing steps can be reduced.
Further, the core 110 made of amorphous metal formed in a bulk shape has extremely high magnetic permeability, so that the receiving sensitivity of the antenna 100 can be extremely improved. In addition, since the amorphous metal has high strength, the core 110 can be formed extremely thin and the number of turns of the coil 120 can be increased, so that the receiving sensitivity of the antenna 100 can be improved. In addition, since amorphous metal is hard to be rusted and has good temperature stability, the lifetime of the antenna 100 can be further extended.

  In addition, since the wristwatch 1 incorporates the antenna 100 with improved reception sensitivity than before, the wristwatch 1 that can receive radio waves with high sensitivity can be provided.

  The antenna 100 according to Embodiment 1 of the present invention may be modified as follows as necessary.

(Modification 1)
FIG. 5 is a diagram for explaining an antenna 200 according to the first modification of the first embodiment. FIG. 6 is a diagram for explaining the configuration of the antenna 200 according to the first modification of the first embodiment.
As shown in FIG. 5, an antenna 200 obtained by modifying the antenna 100 according to the first embodiment includes a magnetic core 210, a coil 220 wound around the core 210, and the like.
Similarly to the antenna 100 of the first embodiment, the antenna 200 has a lower portion of the dial 5 such that the dial 5 and the axis X of the longitudinal central portion 210B of a core 210 (described later) of the antenna 200 are parallel to each other. Is arranged.

As with the antenna 100 of the first embodiment, the core 210 is formed in a bulk shape using an amorphous metal as a material. As shown in FIG. 5, the core 210 has a substantially rectangular parallelepiped shape having two planes substantially parallel to the dial 5. 210 A of protrusion parts and the core 210 which has the center part 210B of the longitudinal direction of the elongate rod-shaped body with a circular cross section are formed. More specifically, as shown in FIGS. 5 and 6, an engagement hole 210 </ b> F that engages an end 210 </ b> E in the longitudinal direction of the core 210 is provided at the lower portion of the bulging portion 210 </ b> A. By engaging the end portion 210E of the core 210 in the longitudinal direction with the hole 210F, the bulging portion 210A and the core 210 are connected and fixed. The area of the flat surface on the opposite surface 210C facing the dial plate 5 of the bulging portion 210A across the axis X of the central portion 210B in the longitudinal direction of the core 210 is the flat surface on the opposite surface 210D side of the opposite surface 210C. It is wider (larger). In addition, the cross-sectional area of the central portion 210B in the longitudinal direction of the core 210 is smaller than the cross-sectional areas of the bulging portions 210A and 210A that the both end portions 210E and 210E of the core 210 have.
The adhesive for connecting and fixing the bulging portion 210A and the end portion 210E in the longitudinal direction of the core 210 may be any adhesive as long as it adheres amorphous metals to each other, but it can prevent eddy current loss. From the viewpoint, a non-conductive adhesive is more desirable.
In addition, since the core 210 is made of an amorphous metal, for example, even if the central portion 210B in the longitudinal direction is made thinner than the core formed of ferrite, the same or higher strength can be obtained.

When the antenna 200 is placed in the signal magnetic field so that the axis of the coil 220 is parallel to the magnetic field direction, the signal magnetic field M1 is applied to the core 210 having a higher relative permeability than the surrounding space, as shown in FIG. concentrate. As a result, the signal magnetic flux M1 and the coil 220 are linked to each other, and an induced electromotive force is generated in the coil 220 so as to generate the generated magnetic flux M2 in a direction that prevents the change of the signal magnetic flux M1 inside the coil 220 according to Lenz's law. V is generated.
The induced electromotive force V generated in the coil 220 is detected by a receiving circuit (not shown) connected to the coil 220.

  Here, the end 210E in the longitudinal direction of the core 210 is connected and fixed to the lower portion of the bulging portion 210A, and faces the dial 5 of the bulging portion 210A across the axis X of the central portion 210B in the longitudinal direction of the core 210. Since the area of the plane on the opposite surface 210C side is wider (larger) than the plane on the opposite surface 210D side of the opposite surface 210C, the axis 210 of the core 210 in the longitudinal direction center portion 210B is sandwiched between The radio wave reception area on the facing surface 210C side of the dial plate 5 in the bulging portions 210A and 210A at both ends 210E and 210E in the longitudinal direction is wider (larger) than the radio wave reception area on the opposite surface 210D side of the facing surface 210C. ing. Therefore, when the antenna 200 receives the radio wave, the opposed surface 210C of the dial plate 5 of the core 210 receives the received radio wave amount compared to the opposite surface 210D side of the opposed surface 210C across the axis X of the antenna 200. The shape is increased.

Further, the antenna 200 has a larger received radio wave amount on the opposite surface 210C side of the dial plate 5 of the bulging portion 210A than on the opposite surface 210D side of the opposite surface 210C across the axis X of the antenna 200. Because of the shape, the generated magnetic flux M2 is larger on the facing surface 210C side of the dial plate 5 of the bulging portion 210A than on the opposite surface 210D side of the facing surface 210C. The generated magnetic flux M2 generated on the opposite surface 210D side of the opposed surface 210C of the dial plate 5 of the bulging portion 210A across the axis X of the antenna 200 passes through the back cover (not shown) and generates eddy currents in the back cover. To cause eddy current loss of the signal magnetic flux M1. On the other hand, the generated magnetic flux M2 on the opposite surface 210D side of the opposed surface 210C of the dial plate 5 of the bulging portion 210A across the axis X of the antenna 200 is suppressed to be less than that on the opposed surface 210C side. The eddy current generated in the back cover (not shown) is suppressed, and the eddy current loss of the signal magnetic flux M1 is suppressed.
Therefore, in the antenna 200 of the first modification and the wristwatch incorporating the antenna 200, the core 210 can be easily formed, as well as the effects similar to those of the antenna 100 and the wristwatch 1 of the first embodiment. Since it can be manufactured by connecting the bulging portion 210A and the end portion 210E of the core 210, the antenna 200 can be manufactured more easily. Further, since the antenna 200 is manufactured by combining the bulging portion 210A and the core 210, it is relatively easy to manufacture even an antenna having a complicated shape by combining the bulging portion and the central portion having various shapes. can do.

(Embodiment 2)
As shown in FIGS. 7, 8, and 9, the wristwatch 1 a according to the second embodiment of the present invention differs from the antenna 100 of the first embodiment only in the structure of the antenna 300, and thus has the same configuration as the wristwatch 1 of the first embodiment. Are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 7 is a plan view of a wristwatch 1a incorporating the antenna 300 according to Embodiment 2 of the present invention, and FIG. 8 is a cross-sectional view taken along the line II-II in FIG.
FIG. 9 is a diagram for explaining the antenna 300 according to the second embodiment.
As shown in FIG. 8, the antenna 300 is disposed under the dial 5 as a decorative plate.
As shown in FIG. 9, the antenna 300 according to the second embodiment includes a core 310 that is a magnetic material, a coil 320 wound around the core 310, and cores at both ends 310 </ b> A and 310 </ b> A in the longitudinal direction of the core 310. The magnetic sheets 310C, 310C and the like attached so as to protrude outward from 310 are configured.

As shown in FIG. 9, the core 310 is, for example, a long rod-like body having a circular cross section, and the longitudinal end portion 310 </ b> A of the core 310 is formed in a planar shape, for example. A magnetic sheet 310 </ b> C is attached to the end portion 310 </ b> A so as to protrude outward from the core 310. The core 310 is three-dimensionally formed in a bulk shape using an amorphous metal as a material, like the core 110 of the antenna 100. The magnetic sheet 310C is formed in a sheet shape or a foil shape using an amorphous metal or another magnetic material as a material.
And since the core 310 consists of an amorphous metal, even if it makes the center part 310B of the longitudinal direction of the core 310 thinner than the core formed from the ferrite, for example, the intensity | strength more than equivalent can be acquired.
In addition, a coil 320 is wound around the core 310B in the longitudinal direction in layers.

When the core 310 is placed in the signal magnetic field so that the axis X of the central portion 310B in the longitudinal direction of the coil 320 is parallel to the magnetic field direction, the signal magnetic flux M1 is larger than the surrounding space as shown in FIG. It concentrates on the core 310 with high relative permeability. As a result, the signal magnetic flux M1 and the coil 320 are interlinked, and the induced electromotive force that generates the generated magnetic flux M2 in the direction that prevents the change of the signal magnetic flux M1 inside the coil 320 according to Lenz's law. V is generated.
The induced electromotive force V generated in the coil 320 is detected by a receiving circuit (not shown) connected to the coil 320.

  According to the antenna 300 according to the second embodiment and the wristwatch 1a incorporating the antenna 300 described above, the plane of the magnetic sheet 310C attached to the end 310A in the longitudinal direction of the core 310 is used as a radio wave receiving surface. Therefore, a wider (larger) reception area can be secured without requiring much three-dimensional space, and the reception sensitivity of the antenna 300 can be improved.

  In addition, since amorphous metal has high strength, the magnetic sheet 310C can be thinned without being torn.

  In addition, since the wristwatch 1a includes the antenna 300 with improved reception sensitivity, the wristwatch 1a that can receive radio waves with high sensitivity can be provided.

(Embodiment 3)
As shown in FIGS. 10, 11, and 12, the wristwatch 1 b according to the third embodiment of the present invention differs from the antenna 100 of the first embodiment only in the structure of the magnetic sheet 5 c as a magnetic layer and the antenna 400. About the structure similar to 1 wristwatch 1, while attaching | subjecting the same code | symbol, the description is abbreviate | omitted.

  FIG. 10 is a plan view of a wristwatch 1b incorporating the antenna 400 according to the third embodiment, and FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. FIG. 12 is a diagram illustrating a state in which the antenna 400 is built in the wristwatch 1b according to the third embodiment.

As shown in FIG. 11, the antenna 400 is supported by the upper housing part 4a and is disposed between the lower part of the dial plate 5 as a decorative plate and the upper part of the lower housing part 4b. The dial plate 5 and the axis 410 of the central portion 410B in the longitudinal direction of the core 410 (described later) of the antenna 400 are arranged in parallel.
A magnetic sheet 5c is provided on the lower surface of the dial plate 5, that is, the surface on the antenna 400 side.

As shown in FIG. 10, the magnetic sheet 5 c is affixed to an area outside the area facing the central portion 410 </ b> B (described later) of the antenna 400 on the antenna 400 side surface of the dial 5. ing.
The magnetic sheet 5c is, for example, a substantially fan-shaped sheet surrounded by an arc slightly smaller than the arc of the outer shape of the dial 5 and a straight line connecting both ends of the arc. As the magnetic material for forming the magnetic sheet 5c, amorphous metal, ferrite, or the like can be used. However, a material having higher strength is better from the viewpoint of preventing the sheet from being torn and is preferably formed from amorphous metal.

  As shown in FIG. 12, the antenna 400 includes a magnetic core 410 and a coil 420 wound around the core 410.

The core 410 is formed in a bulk shape using an amorphous metal as a material, for example, similarly to the core 110, and has a substantially rectangular parallelepiped bulging portion 410A having a plane substantially parallel to the dial plate 5 as shown in FIG. And a central portion 410B in the longitudinal direction of a long rod-like body having a circular cross section.
Further, since the core 410 is made of an amorphous metal, for example, even if the central portion 410B in the longitudinal direction is made thinner than the core formed of ferrite, the same or higher strength can be obtained.
The antenna 400 is arranged such that the bulging portions 410A and 410A at both ends of the core 410 are in contact with the magnetic sheet 5c attached to the dial plate 5, and the bulging portion 410A and the magnetic sheet 5c are It is designed to be magnetically coupled.

  As shown in FIG. 12, the antenna 400 as described above is arranged on the upper side of the back cover 2 c inside the watch case 2, and the dial 5 having the magnetic sheet 5 c provided on the upper side of the antenna 400. Is arranged.

According to the antenna 400 according to the third embodiment described above, the magnetic sheet 5c attached to the lower surface of the dial plate 5, that is, the surface on the antenna 400 side is used as a radio wave receiving surface, and radio waves are transmitted from the surface of the magnetic sheet 5c. Can be received. That is, when the antenna 400 is placed in the signal magnetic field so that the axis of the coil 420 is parallel to the magnetic field direction, the magnetic flux (not shown) due to the signal magnetic field bulges at the ends of the magnetic sheet 5c and the core 410. Collected in the core 410 via the part 410A. As a result, the signal magnetic flux (not shown) and the coil 420 are linked, and the coil 420 has a magnetic flux (not shown) in a direction that prevents the change of the signal magnetic flux (not shown) inside the coil 420 according to Lenz's law. An induced electromotive force V is generated so as to generate Therefore, the radio wave from the dial plate 5 side can be received efficiently.
Since the antenna 400 can receive radio waves by the surface of the magnetic sheet 5c having a large area, the antenna 400 can receive more radio waves, and the reception sensitivity of the antenna 400 can be improved. The wristwatch 1b that can be received well can be provided.

  In addition, since the amorphous metal has high strength, the magnetic sheet 5c can be thinned without being torn.

In addition, since the core 410 is manufactured by molding amorphous metal into a bulk shape, the core 410 has a free shape compared to a core formed by stacking a plurality of conventional amorphous metal thin films. It becomes easy to process, and the antenna 400 having a shape suitable for the purpose can be manufactured more easily. In addition, since a thin film is not stacked unlike a conventional amorphous metal core, the number of processing steps can be reduced.
In addition, since the core 410 made of amorphous metal formed in a bulk shape has extremely high magnetic permeability, the reception sensitivity of the antenna 400 can be extremely improved. In addition, since the amorphous metal has high strength, the core 410 can be formed extremely thin, and the number of turns of the coil 420 can be increased, so that the reception sensitivity of the antenna 400 can be improved. In addition, since amorphous metal is less rusting and has good temperature stability, the life of the antenna 400 can be further extended.
In the third embodiment, the magnetic layer is formed of the magnetic sheet 5c. However, the magnetic layer may be formed by chemically or physically applying a magnetic material such as amorphous metal.
In addition, the antenna 400 is arranged so that the bulging portions 410A and 410A provided at both ends of the core 410 are in contact with the magnetic sheet 5c attached to the dial plate 5, but the antenna 400 is arranged in such a manner. The protruding portion 410A may be disposed so as to face the magnetic sheet 5c with a space that can be magnetically coupled.
In addition, the shape of the bulging portion 410A at the end of the core 410 is not limited to this, and may be any shape as long as it can be magnetically coupled to the magnetic sheet 5c.

In the embodiment of the present invention, the core is formed from an amorphous metal, but may be formed from a magnetic material such as ferrite.
In the present embodiment, the case where the electronic device is applied to an antenna that receives a standard radio wave built in a wristwatch-type radio timepiece has been described. However, the application of the present invention is not limited to this. For example, the present invention may be applied to an antenna for vehicle equipment, a keyless entry system, and an IC tag.

It is a top view which shows the wristwatch which incorporated the antenna which concerns on Embodiment 1 of this invention. It is II-II sectional drawing of FIG. It is a figure explaining the antenna which concerns on Embodiment 1 of this invention. It is a block diagram which shows the internal structure of the wristwatch which concerns on this invention. It is a figure explaining the antenna which concerns on the modification 1 of Embodiment 1 of this invention. It is a figure explaining the structure of the antenna which concerns on the modification 1 of Embodiment 1 of this invention. It is a top view which shows the wristwatch which incorporated the antenna which concerns on Embodiment 2 of this invention. It is VIII-VIII sectional drawing of FIG. It is a figure explaining the antenna which concerns on Embodiment 2 of this invention. It is a top view which shows the wristwatch which incorporated the antenna which concerns on Embodiment 3 of this invention. It is XI-XI sectional drawing of FIG. It is a figure explaining a mode that the antenna which concerns on Embodiment 3 of this invention is incorporated in a wristwatch.

Explanation of symbols

1,1a, 1b Wristwatch (electronic equipment)
2 watch case
5 Dial (decorative board)
5c Magnetic sheet (magnetic layer)
60 Communication control unit 62 Radio wave receiving device 100, 200, 300, 400 Antenna 110, 210, 310, 410 Core 210E, 310A End portion 110A, 210A, 410A Bumping portion 110B, 210B, 310B, 410B Central portion 110C, 210C Opposing Surface 110D, 210D Opposite surface 310C Magnetic sheet 120, 220, 320, 420 Coil X axis

Claims (18)

A rod-shaped core,
A bulging portion for receiving radio waves having at the end in the longitudinal direction of the core;
A coil wound around a central portion of the core in the longitudinal direction;
A radio wave transmitting decorative plate, wherein the core is disposed at a lower portion of the decorative plate, and the bulging portion is placed on the decorative plate across an axis of a central portion in the longitudinal direction of the core when receiving radio waves. An antenna having a shape in which an amount of received radio waves on an opposite surface side is larger than that on the opposite surface side of the opposite surface.   The antenna according to claim 1, wherein the bulging portion is bent in a direction from an end portion in a longitudinal direction of the core toward the decorative plate.   2. The antenna according to claim 1, wherein the bulging portion has an area of a facing surface facing the decorative plate that is larger than a cross-sectional area of a central portion in a longitudinal direction of the core.   2. The antenna according to claim 1, wherein the bulging portion has a radio wave reception area on the opposite surface side facing the decorative plate that is larger than a radio wave reception area on the opposite surface side of the opposite surface across the axis. .   The bulging portion is bent in a direction from the end in the longitudinal direction of the core toward the decorative plate, and the diameter of the bulging portion is gradually reduced toward the central portion in the longitudinal direction of the core. The antenna according to claim 1, wherein the antenna is substantially constant at a central portion in a longitudinal direction of the core. A rod-shaped core,
A coil wound around a central portion of the core in the longitudinal direction;
An electromagnetic wave transmitting decorative plate, wherein the core is disposed at a lower portion of the decorative plate, and a magnetic sheet is attached to an end of the core in a longitudinal direction so as to protrude outward from the core. An antenna characterized by the fact that   The antenna according to claim 6, wherein the magnetic sheet is made of an amorphous metal.   The antenna according to any one of claims 1 to 7, wherein the core is made of bulk amorphous metal. A radio-opaque case with an opening at the top;
A radio wave transmitting decorative plate disposed on the opening side of the case;
A rod-shaped core, a bulging portion for receiving radio waves at the longitudinal end portion of the core, and an antenna having a coil wound around the central portion in the longitudinal direction of the core,
The antenna is disposed at a lower part of the decorative plate, and when the bulging portion receives radio waves, the amount of received radio waves on the opposite surface side facing the decorative plate across the axis of the antenna is An electronic device characterized by having a shape that is larger than that on the opposite side.   The electronic device according to claim 9, wherein the bulging portion is bent in a direction from an end portion in a longitudinal direction of the core toward the decorative plate.   The electronic device according to claim 9, wherein the bulging portion has an area of a facing surface facing the decorative plate that is larger than a cross-sectional area of a central portion in a longitudinal direction of the core.   10. The electron according to claim 9, wherein the bulging portion has a radio wave reception area on the opposite surface side facing the decorative plate that is larger than a radio wave reception area on the opposite surface side of the opposite surface across the axis. machine.   The bulging portion is bent in a direction from the end portion in the longitudinal direction of the core toward the decorative plate, and the diameter of the bulging portion is gradually reduced toward the central portion in the longitudinal direction of the core. The electronic device according to claim 9, wherein the electronic device is substantially constant at a central portion in a longitudinal direction of the core. A radio-opaque case with an opening at the top;
A radio wave transmitting decorative plate disposed on the opening side of the case;
A rod-shaped core, an antenna having a coil wound around the central portion in the longitudinal direction of the core, and
The antenna is disposed at a lower portion of the decorative plate, and a magnetic sheet is attached to an end portion in the longitudinal direction of the core so as to protrude outward from the core. A radio-opaque case with an opening at the top;
A radio wave transmitting decorative plate disposed on the opening side of the case;
A rod-shaped core, a bulging portion for receiving radio waves at the longitudinal end portion of the core, and an antenna having a coil wound around the central portion in the longitudinal direction of the core,
The antenna is disposed at a lower portion of the decorative plate, and a magnetic layer formed on a lower surface of the decorative plate and the bulging portion are magnetically coupled to each other. The magnetic layer is
The electronic device according to claim 15, comprising a magnetic sheet attached to a lower surface of the decorative plate.   The electronic device according to claim 14, wherein the magnetic sheet is made of an amorphous metal.   The electronic device according to claim 9, wherein the core is made of bulk amorphous metal.

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