JP5764013B2 - Small electronic device - Google Patents

Description

  The present invention relates to a small electronic device, for example, using an inverted F antenna.

In recent years, there has been a growing demand for high-performance antennas that can be built into small electronic devices such as wrist watches, portable terminals, and sensors.
As such a technique, Patent Document 1 discloses a technique for providing an antenna on a wristwatch.
In this technique, an inverted F antenna that is grounded to the cylindrical housing is provided on the outer peripheral surface of a metal container that houses an operation mechanism of a timepiece.

However, when the antenna is provided on the outer peripheral surface of the metal container, there is a problem in that the timepiece is increased in size because a dielectric housing covering the outer periphery is required.
In addition, there is a demand to make the watch case made of metal, and when installing an antenna inside the metal case, there is not enough antenna performance due to the influence of the metal container, and there is a space for installing the watch mechanism There was a problem of being restricted.

JP 2001-185927 A

  An object of the present invention is to accommodate a high-performance antenna in a small casing formed of a conductor.

According to the first aspect of the present invention, the first conductive plate functioning as a grounding portion, the second conductive plate for excitation arranged in parallel with the first conductive plate, and one end of the first conductive plate A short-circuit member connected to the plate and having the other end connected to the second conductive plate, and connected to the second conductive plate at a predetermined distance from the short-circuit member, and penetrates the first conductive plate. A transmission member; a receiving unit that detects the excitation generated in the second conductive plate by a radio wave transmitted from a radio wave transmission source through the transmission member; A conductive casing formed with a recess for accommodating the plate, the second conductive plate, the short-circuit member, the transmission member, and the receiving unit, and the second conductive plate includes the recess By bending or bending along the inner circumference, the electrical length on the outer circumference side with respect to the center line in the longitudinal direction is reduced. Is formed in a long and consists shape than the electrical length of the peripheral portion, and the inner peripheral surface of the recess of the housing and the outer peripheral portion, the resonance frequency is arranged in proximity to or below a predetermined distance to shift to the low frequency side A small electronic device is provided.
According to a second aspect of the present invention, there is provided the small electronic device according to the first aspect, wherein the first conductive plate is held in parallel with the bottom surface of the recess.

  According to the present invention, by using an inverted-F antenna, a high-performance antenna can be accommodated in a small casing formed of a conductor.

It is a figure for demonstrating the structure of a timepiece apparatus. It is a figure for demonstrating the relationship between the width | variety of an excitation conductive plate and a grounding conductive plate. It is a figure for demonstrating the various shapes of an excitation electrically conductive plate. It is a figure for demonstrating the example which loads a capacity | capacitance to an excitation electrically conductive plate. It is a figure for demonstrating the example which makes an excitation electrically conductive plate a parasitic structure. It is a figure for demonstrating the example which makes an excitation electrically conductive board a stack structure. It is explanatory drawing of the inverted F antenna part which enabled multi-frequency response by the stack structure. It is explanatory drawing of the inverted-F antenna part 3 which changed the frequency characteristic of the antenna. It is a figure for demonstrating an experimental result. It is a figure for demonstrating a simulation result.

(1) Outline of Embodiment A timepiece device 1 (FIG. 1B) has a housing 2 made of a metal concave container. In addition, an inverted F antenna unit 3 for receiving radio waves from GPS satellites is provided.
Although the reverse F antenna unit 3 is on the back of the dial 11, since the dial 11 is a dielectric, the reverse F antenna unit 3 can receive the radio wave transmitted through the glass plate 12 and the dial 11. it can.

The inventor of the present application has made it clear from the experiment that the inverted F antenna unit 3 is not easily affected by the case 2 made of metal. Time information is acquired and time correction is performed.
Also, the inverted F antenna section 3 can be multi-frequencyd by forming a plurality of electrical length portions on the excitation conductive plate 4 depending on the shape of the excitation conductive plate 4.
Further, when the inner peripheral surface of the recess 10 and at least a part of the outer peripheral portion of the excitation conductive plate 4 are brought close to each other at a predetermined distance or less, the resonance frequency of the inverted F antenna unit 3 can be lowered. Thereby, the reverse F antenna part 3 can be reduced in size.

As described above, in the present embodiment, an inverted F antenna is placed in the cavity (housing 2) to reduce the size of the electronic device and include an element (excitation conductive plate 4) that can handle multiple frequencies.
Further, by loading C (capacitance) on the inverted F antenna with a cavity, the resonance frequency is controlled and further miniaturization is achieved.

(2) Details of Embodiment In this embodiment, an inverted F antenna is installed inside the timepiece device, and as an example, a radio wave from a GPS (Global Positioning Systems) satellite is received.
The GPS satellite transmits time information, and the clock device automatically corrects the displayed time using this.
Thus, the time can be automatically corrected anywhere in the world as long as it can receive radio waves from GPS satellites.

The experiment of the inventor of the present application revealed that an inverted F antenna is effective when an antenna is installed in a metal concave container like a wristwatch case. The experimental results will be explained later.
In addition, the inverted F antenna has a small size, light weight, occupation ratio (ratio of the area occupied in the wristwatch case), laterality (a property that can be bent in accordance with the wristwatch case), and back side (back of the dial). Therefore, it is suitable for mounting on watches and other small electronic devices.

Fig.1 (a) is the figure which showed the place which looked at the timepiece apparatus 1 which concerns on this Embodiment from the upper surface.
In addition, in order to avoid complication, the housing | casing 2 and the reverse F antenna part 3 are shown in figure, and the other structure is abbreviate | omitted.
Although the timepiece device 1 is configured for a wristwatch, it may be a stationary timepiece.

The housing 2 is a concave container (cavity) in which a concave portion 10 is formed by a cylindrical portion and a bottom portion, and is made of, for example, a metal such as stainless steel. The inner diameter of the cylindrical portion may be about 40 [mm] or less.
In addition, in this Embodiment, although the housing | casing 2 is formed in a cylindrical shape, what is necessary is just a concave container, such as a shape which has a rectangular bottom face and a rectangular side surface.
The inverted F antenna unit 3 includes a ground conductive plate 7, an excitation conductive plate 4, a short-circuit pin 5, and a transmission pin 6. In this embodiment, the inverted F antenna unit 3 forms a cavity-loaded inverted F antenna.

  The ground conductive plate 7 is curved along the inner peripheral surface of the housing 2, and the outer peripheral side is joined to the inner peripheral surface of the housing 2 so that the plate surface is parallel to the bottom surface of the recess 10. The ground conductive plate 7 is electrically connected to the housing 2, but may be insulated.

The excitation conductive plate (radiation conductive plate) 4 is curved corresponding to the shape of the ground conductive plate 7, and is placed in a space above the ground conductive plate 7 by a short-circuit pin 5 provided at one end of the excitation conductive plate 4. It is supported in parallel with the ground conductive plate 7. However, the excitation conductive plate 4 is only required to be supported in a range where it is not in electrical contact with the ground conductive plate 7, and does not necessarily need to be in a completely parallel state. Also good.
The other end of the excitation conductive plate 4 is an open end.
As described above, the outer peripheral portion of the excitation conductive plate 4 is composed of a curved outer peripheral side, a curved inner peripheral side, and both end portions.

The length of the excitation conductive plate 4 is set to a dimension that is about one-fourth of the wavelength of a radio wave transmitted from a GPS satellite, or one-fourth or less. Since the frequency of the radio wave transmitted from the GPS satellite is 1.5 [GHz], the length of the excitation conductive plate 4 is about 50 [mm] or less than 50 [mm], and is curved. It will be large enough to be stored in a wristwatch.
Further, by disposing a dielectric between the excitation conductive plate 4 and the ground conductive plate 7 to reduce the wavelength of the radio wave, the lengths of the excitation conductive plate 4 and the ground conductive plate 7 are shortened, and the inverted F antenna unit 3 is provided. Further downsizing is possible.

The short-circuit pin 5 has one end joined to the end of the ground conductive plate 7 and the other end joined to the end of the excitation conductive plate 4 to physically support the excitation conductive plate 4 and ground the excitation conductive plate 4 The conductive plate 7 is grounded by being short-circuited.
The transmission pin (feeding pin) 6 is constituted by a central conductor (core wire) such as a coaxial line, and is provided at a predetermined distance from the shorting pin 5 on the open end side of the excitation conductive plate 4 with respect to the shorting pin 5. It has been.
One end of the transmission pin 6 is joined to the excitation conductive plate 4, and the other end passes through a through hole 8 provided in the ground conductive plate 7 and is connected to a timepiece operation unit (not shown).
When the excitation conductive plate 4 is excited by radio waves, a change in potential of the excitation conductive plate 4 is transmitted by the transmission pin 6.
As described above, the central conductor such as the coaxial line constituting the transmission pin 6 is connected to the excitation conductive plate 4, while the outer conductor of the coaxial line is connected to the ground conductive plate 7 at the through hole 8 portion.

The excitation conductive plate 4, the shorting pin 5, and the ground conductive plate 7 are all formed of a conductive member using a metal such as brass, but may be formed of a conductive resin or on a dielectric substrate. Is also possible.
When the received radio wave resonates in the recess 10, the performance of the inverted F antenna unit 3 deteriorates. Therefore, the shape and size of the recess 10 are designed so that the resonance frequency of the recess 10 is different from the reception frequency of the inverted F antenna unit 3. .
More preferably, the shape of the recess 10 and the dimensions of the inverted F antenna unit 3 are designed so that the resonance frequency of the recess 10 is outside the bandwidth of the inverted F antenna unit 3. The bandwidth can be adjusted by the distance between the excitation conductive plate 4 and the ground conductive plate 7 or the like.

FIG. 1B is a cross-sectional view of the timepiece device 1 as viewed from the side.
A dial 11 for time display is fitted on the opening side of the recess 10, and a glass plate 12 for protecting the dial 11 and the like is fitted on the end of the opening of the recess 10.
An inverted F antenna unit 3 is disposed on the back of the dial 11. The dial 11 is formed of a dielectric, and radio waves from the GPS satellite pass through the glass plate 12 and the dial 11 to reach the inverted F antenna unit 3.

A region where the inverted F antenna portion 3 is not formed under the dial 11 of the recess 10, that is, a space below the inverted F antenna portion 3 and a space on the inner peripheral side of the curved portion of the inverted F antenna portion 3. The clock operating unit 21 is installed.
Since the inverted F antenna unit 3 is curved along the inner peripheral surface of the housing 2, a sufficient space for installing the timepiece operation unit 21 in the recess 10 can be secured.

The timepiece operation unit 21 includes an hour hand driving motor, a crystal oscillator, and the like, and is driven by a built-in battery (not shown).
The timepiece operation unit 21 drives the short hand 22, the long hand 23, the second hand (not shown), and the like with a motor in accordance with the vibration of the crystal resonator.
The user of the timepiece device 1 can recognize the current time with the short hand 22 and the long hand 23 on the dial 11. The timepiece device 1 may be a digital timepiece instead of an analog timepiece.

Further, the clock operation unit 21 receives the GPS signal by the transmission pin 6 and detects the current date and time from the time information included in the GPS signal. Then, the timepiece operation unit 21 drives the motor so as to coincide with the detected current date and time, and adjusts the positions of the short hand 22, the long hand 23, and the second hand.
As described above, the timepiece device 1 can receive the GPS signal by the inverted F antenna unit 3 and automatically correct the time.

FIG. 2 is a diagram for explaining the relationship between the widths of the excitation conductive plate 4 and the ground conductive plate 7.
The width W2 of the ground conductive plate 7 is preferably equal to or greater than the width W1 of the excitation conductive plate 4, and more preferably W2 ≧ 2W1. The length of the ground conductive plate 7 is preferably equal to or greater than the length of the excitation conductive plate 4.

Each drawing in FIG. 3 is a diagram for explaining various shapes of the excitation conductive plate.
FIG. 3A shows an example in which the excitation conductive plate 4 is formed by circular arcs on the inner peripheral side and the outer peripheral side. In this case, the electrical length 31 on the inner peripheral side is shorter than the electrical length 32 on the outer peripheral side with respect to the target line of the short-circuit pin 5. For this reason, there are two resonance frequencies corresponding to the electrical length 31 and those corresponding to the electrical length 32, and the multi-frequency of the inverted F antenna unit 3 can be achieved. The electrical length 31 and the electrical length 32 may be made equal by forming a convex portion on the inner peripheral side or forming irregularities.

FIG. 3B is an example in which recesses 41, 41, 41 are provided on the inner peripheral side of the excitation conductive plate 4 so that the inner peripheral electrical length 31 is equal to the outer peripheral electrical length 32.
When it is not necessary to increase the frequency of the inverted F antenna unit 3, the electrical lengths 31 and 32 are formed to be equal. On the other hand, even if the electrical lengths 31 and 32 are different as shown in FIG. 3A, the frequency is reduced to a single frequency by adjusting the distance between the short-circuit pin 5 and the transmission pin 6 or the element shape thereof. You can also.

FIG. 3C shows an example in which the excitation conductive plate 4 is provided with the U-shaped slits 43a, 43b, 43c to further increase the frequency.
The slits 43 a, 43 b, and 43 c are formed in this order from the short-circuit pin 5 toward the tip of the excitation conductive plate 4 so that the letter-shaped shape is symmetric with respect to the center line of the excitation conductive plate 4.
On the inner peripheral side of the excitation conductive plate 4, there are electric lengths 31a, 31b, 31c corresponding to the slits 43a, 43b, 43c in addition to the electric length 31d corresponding to the entire inner peripheral side.
Similarly, electrical lengths 32a, 32b, 32c, and 32d exist on the outer peripheral side of the excitation conductive plate 4. For this reason, in the inverted F antenna unit 3, multiple frequencies can be achieved.

FIG. 3D is an example in which concave portions 45, 45, 45 are provided on the outer peripheral side of the excitation conductive plate 4 to further increase the difference in electrical length between the inner and outer periphery.
Thereby, the difference of the resonant frequency of an inner peripheral side and an outer peripheral side can be enlarged more. In addition, you may form a convex part in an outer peripheral side, or may form an unevenness | corrugation, and may enlarge an electrical length difference.

Next, an example in which the inverted F antenna unit 3 is reduced in size by loading the excitation conductive plate 4 with a capacitor will be described.
According to an experiment by the present inventor, it has been found that when a conductive member is installed in the vicinity of the outer peripheral portion of the excitation conductive plate 4, the resonance frequency of the inverted F antenna portion 3 is lowered.
This means that, for the same frequency, the inverted F antenna unit 3 can be reduced in size when the conductive member is installed rather than when the conductive member is not installed.
Therefore, in the following, an example in which a metal member is installed as a conductive member in the vicinity of the excitation conductive plate 4 will be described.

FIG. 4A is an example in which a protrusion 51 (stub) is provided on the inner peripheral surface of the recess 10 formed in the housing 2 so as to face the outer peripheral surface of the open end of the excitation conductive plate 4. In the following, the ground conductive plate 7 is not shown in order to avoid complication of the drawing.
The protrusion 51 is formed of a metal plate, and is formed on the same plane as the excitation conductive plate 4 or on the upper surface or the lower surface of the excitation conductive plate 4.
The outer peripheral side of the protrusion 51 is grounded to the inner peripheral surface of the recess 10, and the inner peripheral side is an open end.

When the projecting portion 51 is formed in this way, the opposing portions of the projecting portion 51 and the excitation conductive plate 4 are coupled by the capacitance, so that the capacitance is loaded on the excitation conductive plate 4 and the resonance frequency of the excitation conductive plate 4 is reduced. Even if the excitation conductive plate 4 is downsized, radio waves from GPS satellites can be received.
Further, a dielectric can be provided between the ground conductive plate 7 and the excitation conductive plate 4 to further reduce the size.

FIG. 4B is an example in which a protrusion 51 is provided on the side of the shorting pin 5 of the excitation conductive plate 4. Thus, the protrusion 51 may be formed on the short-circuit pin 5 side.
FIG. 4C is an example in which protrusions 51 are provided on both the open end side and the shorting pin 5 side of the excitation conductive plate 4. As described above, when a plurality of protrusions 51 are provided, the resonance frequency can be shifted to the lower frequency side.

FIG. 4D shows an example in which the excitation conductive plate 4 is formed of a rectangular metal plate and arranged at the center of the recess 10. A center line in the longitudinal direction is located at the center of the housing 2.
On the side of the short-circuit pin 5 of the excitation conductive plate 4, a protrusion 51 that faces the end of the excitation conductive plate 4 is provided on the inner peripheral surface of the recess 10. Thus, the excitation conductive plate 4 can be formed in a rectangular shape.

FIG. 4E shows an example in which a protrusion 51 is provided on the free end side of the excitation conductive plate 4 having a rectangular shape.
FIG. 4F shows an example in which protrusions 51 are provided on both the shorting pin 5 side and the free end side of the excitation conductive plate 4.

FIG. 4G shows that the excitation conductive plate 4 is loaded with a capacity by bringing the outer peripheral side of the excitation conductive plate 4 curved along the inner peripheral surface of the concave portion 10 close to the inner peripheral surface of the concave portion 10. This is an example in which the resonance frequency of the plate 4 is reduced.
In this case, the resonance frequency of the excitation conductive plate 4 can be shifted to the low frequency side without providing the protrusion 51.

  FIG. 4 (h) shows the capacitance generated between the excitation conductive plate 4 and the housing 2 by bringing the short-circuit pin 5 side of the rectangular excitation conductive plate 4 close to the inner peripheral surface of the recess 10. This is an example in which the resonance frequency of the excitation conductive plate 4 is reduced. The end of the excitation conductive plate 4 on the shorting pin 5 side is formed in an arc shape along the inner peripheral surface of the recess 10.

FIG. 4I shows an example in which the excitation conductive plate 4 is formed in an elliptical shape. Thus, the excitation conductive plate 4 can be formed in an elliptical shape or a circular shape. In this case, a cut portion may be provided on the outer periphery of the excitation conductive plate 4 in order to induce a specific mode in the excitation conductive plate 4.
The short-circuit pin 5 is provided on the end side of the long axis, and the end is provided close to the inner peripheral surface of the housing 2.
The distance between the outer periphery of the excitation conductive plate 4 and the inner periphery of the recess 10 increases as the distance from the short-circuit pin 5 increases, and decreases as the distance from the short-circuit pin 5 increases. For this reason, a capacity is loaded in the vicinity of the short-circuit pin 5, and the resonance frequency of the excitation conductive plate 4 can be shifted to the low frequency side.

FIG. 4J is an example in which a protrusion 51 is provided on the outer peripheral side of the free end of the excitation conductive plate 4. The protrusion 51 and the inner peripheral surface of the recess 10 are coupled by capacitance, and the resonance frequency of the excitation conductive plate 4 is shifted to the low frequency side. Thus, the protrusion 51 may be provided on the excitation conductive plate 4.
As described above, the protrusion 51 is provided on the outer peripheral portion of the excitation conductive plate 4, and the resonance frequency of the excitation conductive plate 4 is reduced to the lower frequency side even when the inner peripheral surface of the protrusion 51 and the concave portion 10 becomes a predetermined value or less. Can be shifted.

FIG. 4K is an example in which the housing 2 is formed in a rectangular shape and the excitation conductive plate 4 is bent along the inner periphery of the recess 10.
On the outer peripheral side of the free end, a protrusion 51 that is close to the inner peripheral surface of the recess 10 is provided. The protrusion 51 may be provided on the inner periphery of the recess 10.
In this way, the excitation conductive plate 4 may be bent and formed.
4A to 4F, FIGS. 4J and 4K, the protrusion 51 is provided at a position corresponding to the end of the excitation conductive plate 4, but is provided at an intermediate point or the like. The position is not limited.

Each drawing in FIG. 5 is a diagram for explaining a case where a plurality of excitation conductive plates 4 have a parasitic structure in which a plurality of excitation conductive plates 4 are arranged in the plane of the excitation conductive plate 4.
When the plurality of excitation conductive plates 4 are coupled by capacitance, the resonance frequency is shifted to a lower frequency side, and the excitation conductive plate 4 is curved, so that the resonance frequency can be increased.
In order to avoid complication of the drawing, the casing 2, the ground conductive plate 7, and the like are not shown.

FIGS. 5A to 5C are examples in which the excitation conductive plate 4b is provided at a predetermined distance on the inner peripheral side of the excitation conductive plate 4a.
In FIG. 5A, the excitation conductive plate 4a is grounded by a short-circuit pin 5a and a transmission pin 6a is provided. On the other hand, the excitation conductive plate 4b is provided with a short-circuit pin 5b.
In this case, radio waves are received by the excitation conductive plate 4a. Since the excitation conductive plates 4a and 4b are coupled by capacitance, the resonance frequency of the excitation conductive plate 4a is shifted.

In FIG. 5B, a transmission pin 6b is provided on the excitation conductive plate 4b, and the transmission pin 6a and the transmission pin 6b are coupled by a transmission line.
In this case, both the excitation conductive plates 4a and 4b can be used for reception of radio waves, and the resonance frequency can be shifted and the number of frequencies can be increased.

FIG. 5C shows an example in which the excitation conductive plate 4a is provided with a short-circuit pin 5a, and the excitation conductive plate 4b is provided with a short-circuit pin 5b and a transmission pin 6b.
In this case, radio waves are received by the excitation conductive plate 4b. Since the excitation conductive plates 4a and 4b are coupled by capacitance, the resonance frequency of the excitation conductive plate 4b is shifted to the low frequency side.

In FIG. 5D, excitation conductive plates 4a, 4b, and 4c are arranged in order from the outer peripheral side to the inner peripheral side, the short circuit pin 5a is provided on the excitation conductive plate 4a, and the short circuit pin is provided on the excitation conductive plate 4b. 5b and transmission pin 6b are provided, and the excitation conductive plate 4c is provided with a short-circuit pin 5c.
In this case, radio waves are received by the excitation conductive plate 4b. Since the excitation conductive plate 4b is coupled to the excitation conductive plates 4a and 4c by capacitance, the resonance frequency of the excitation conductive plate 4b is shifted.
Many excitation conductive plates 4 may be arranged on the outer peripheral side of the excitation conductive plate 4a and the inner peripheral side of the excitation conductive plate 4c.

FIG. 5E shows an example in which an excitation conductive plate 4b having an end facing the free end is provided on the free end side of the excitation conductive plate 4a. The excitation conductive plate 4a is provided with a shorting pin 5a and a transmission pin 6a, and the excitation conductive plate 4b is provided with a shorting pin 5b. In this case, radio waves are received by the excitation conductive plate 4a. The free end side of the excitation conductive plate 4a is coupled to the free end side of the excitation conductive plate 4b by a capacitance, and the resonance frequency of the excitation conductive plate 4a is shifted to the low frequency side.
5A to 5D, the respective excitation conductive plates have the same opening angle, but may have different opening angles and lengths.

FIGS. 6 to 8 are views showing the inverted F antenna unit 3 from the side in the case of a stack structure in which the excitation conductive plates 4 are stacked in a direction perpendicular to the plate surface.
In either case, the excitation conductive plate 4a is provided in parallel to the ground conductive plate 7 at a predetermined distance from the ground conductive plate 7, and the excitation conductive plate 4b is excited above the excitation conductive plate 4a by a predetermined distance from the excitation conductive plate 4a. It is provided in parallel to the conductive plate 4a. Here, the meaning of “parallel” does not have to be completely parallel, and may be in a state where it is supported in a range where no electrical contact is made.
The excitation conductive plates 4a and 4b are curved, but may be rectangular.

FIG. 6 illustrates each example of the inverted F antenna unit 3 in which the length of the excitation conductive plate 4a is a1 and the excitation conductive plate 4b having the same length a1 is disposed above.
As described above, according to the inverted F antenna unit 3 shown in each example of FIG. 6, the excitation conductive plate 4 a and the excitation conductive plate 4 b are provided. It can function as a parasitic antenna that is coupled to In addition, by setting the lengths of the excitation conductive plate 4a and the excitation conductive plate 4b to the same a1, it is possible to widen the frequency band and to support a wide band.

FIG. 6A shows an example of the inverted F antenna unit 3 in which the short circuit pin 5a and the transmission pin 6 are provided on the excitation conductive plate 4a, and the short circuit pin 5b is provided on the excitation conductive plate 4b.
In this example, the short-circuit pin 5a and the short-circuit pin 5b are arranged at the same position (end portion in the example in the figure) at the excitation conductive plate 4a and the excitation conductive plate 4b, respectively.
The excitation conductive plate 4a is grounded to the ground conductive plate 7 by a short-circuit pin 5a.
On the other hand, the excitation conductive plate 4b is configured such that the shorting pin 5b is disposed between the excitation conductive plate 4a and the excitation conductive plate 4b so that the grounding conductive plate 7 is interposed via the shorting pin 5a, the end of the excitation conductive plate 4a, and the shorting pin 5b. Is short-circuited.

FIG. 6B shows an inverted F antenna unit 3 in which a short pin 5a and a transmission pin 6 are provided on the excitation conductive plate 4a, and a short pin 5b is provided on the excitation conductive plate 4b and grounded to the ground conductive plate 7 together with the excitation conductive plate 4a. It is an example.
In the inverted F antenna unit 3, unlike the example of FIG. 6A, the excitation conductive plate 4b and the ground conductive plate 7 are directly short-circuited by the short-circuit pin 5b.

FIG. 6C shows an example of the inverted F antenna unit 3 in which the short circuit pin 5a is provided on the excitation conductive plate 4a and the short circuit pin 5b and the transmission pin 6 are provided on the excitation conductive plate 4b.
In the inverted F antenna unit 3 of FIGS. 6A and 6B described above, the lower excitation conductive plate 4a is a feeding antenna and the upper excitation conductive plate 4b is a parasitic antenna, whereas FIG. ) And (d), the inverted F antenna unit 3 is configured to receive radio waves by using the upper excitation conductive plate 4b as a feeding antenna and the lower excitation conductive plate 4a as a parasitic antenna.
As shown in FIGS. 6C and 6D, since the transmission pin 6 is connected to the upper excitation conductive plate 4b, the lower excitation conductive plate 4a has a through-hole provided in the ground conductive plate 7. A through hole through which the transmission pin 6 passes is provided at substantially the same position as the hole.

FIG. 6D is an example of the inverted F antenna unit 3 in which the short circuit pin 5a is provided on the excitation conductive plate 4a and the short circuit pin 5b and the transmission pin 6 are provided on the excitation conductive plate 4b.
As shown in FIG. 6D, the upper excitation conductive plate 4b is used as a feeding antenna and is directly short-circuited to the ground conductive plate 7 by a short-circuit pin 5b.

FIG. 7 shows the inverted F antenna unit 3 that can support a wide band or multiple frequencies by a stack structure.
In each inverted F antenna unit 3 shown in FIGS. 7A to 7D, the arrangement relationship of the excitation conductive plate 4a, the shorting pin 5a, the excitation conductive plate 4b, the shorting pin 5b, the transmission pin 6, and the ground conductive plate 7 is as follows. This is the same as that shown in FIGS.
In each inverted F antenna unit 3 shown in FIG. 6, the excitation conductive plate 4a and the excitation conductive plate 4b are both the same length a1, whereas in the inverted F antenna unit 3 shown in FIG. The length a2 of the excitation conductive plate 4a is different from the length a1 of the excitation conductive plate 4b.
Thus, by changing the length of the excitation conductive plate 4a and the length of the excitation conductive plate 4b, it is possible to cope with a wide band or multiple frequencies.
The values of the lengths a1 and a2 are appropriately selected depending on the frequency to be received.

7A and 7C, in the inverted F antenna unit 3 in which the short-circuit pin 5a and the short-circuit pin 5b are disposed at the same position, the excitation conductivity lower than the length a1 of the upper excitation conductive plate 4b. The length a2 of the plate 4a is increased (a1 <a2).
Accordingly, in FIG. 7A, the feeding antenna is longer than the parasitic antenna, and in FIG. 7C, the feeding antenna side is shorter than the parasitic antenna.
7A and 7C, the length a2 of the lower excitation conductive plate 4a may be shorter than the length a1 of the upper excitation conductive plate 4b (a1> a2).

7B and 7D, the short-circuit pin 5b is directly short-circuited from the excitation conductive plate 4b to the ground conductive plate 7, and the positions of the excitation conductive plate 4a and the excitation conductive plate 4b on the opposite side of the short-circuit pins 5a and 5b are set. By aligning, the length a1 of the upper excitation conductive plate 4b is longer than the length a2 of the lower excitation conductive plate 4a (a1> a2).
7B and 7D, the length a1 of the upper excitation conductive plate 4b may be shorter than the length a2 of the lower excitation conductive plate 4a (a1 <a2).

FIG. 8 shows the structure of the inverted-F antenna unit 3 in which the frequency characteristics of the antenna are changed.
In the inverted-F antenna unit 3 of FIG. 8, the antenna characteristics are changed by changing the position of the short-circuit pin with respect to the feed point to which the transmission pin 6 is connected in the excitation conductive plate on the feed antenna side.
In each inverted F antenna unit 3 shown in FIGS. 8A to 8D, the arrangement relationship of the excitation conductive plate 4a, the shorting pin 5a, the excitation conductive plate 4b, the shorting pin 5b, the transmission pin 6, and the ground conductive plate 7 is as follows. Except for the point that the position of the short-circuit pin 5a or 5b on the power feeding antenna side with respect to the transmission pin 6 is different, it is the same as that shown in FIGS. 6 (a) to 6 (d).

8A and 8B, the shorting pin 5a of the excitation conductive plate 4a is brought close to the transmission pin 6. 8C and 8D, the short-circuit pin 5b of the excitation conductive plate 4b is brought close to the transmission pin 6.
Thus, by bringing the short-circuit pin 5a or the short-circuit pin 5b on the power feeding antenna side closer to the transmission pin 6, the impedance of the antenna is reduced, and various characteristics such as the frequency characteristics of the antenna can be changed.
The distance between each short-circuit pin 5a, 5b and the transmission pin 6 is determined according to the required characteristics of the inverted F antenna unit 3.
It should be noted that even if the position of the short-circuit pin 5a or 5b connected to the excitation conductive plate 4a or 4b on the side that becomes the parasitic antenna is changed with respect to the transmission pin 6, there is no significant change in the antenna characteristics. The state may be sufficient, and you may make it move according to the short circuit pin by the side of a feed antenna.

Next, experimental results will be described.
FIG. 9A is a diagram for explaining an apparatus used in an experiment for examining the influence of the housing 2 on the inverted F antenna unit 3.
In this experiment, a device having a size about one third of that of the timepiece device 1 was created due to the experimental equipment. For this reason, the frequency obtained by multiplying the experimental value by about one third is the value in the timepiece device 1.

The dimensions of the housing 2 are an inner diameter p = 14 [mm], a thickness d = 0.5 [mm], and a height t = 2.0 [mm].
The dielectric disposed on the bottom surface of the housing 2 has a thickness h of 0.6 [mm] and a relative dielectric constant εr of 2.6.
The excitation conductive plate 4 is disposed concentrically with the housing 2 on the upper surface of the dielectric, has a radius of curvature r of 2.63 [mm], and a width of w = 2.0 [mm].
The distance s between the short-circuit pin 5 and the transmission pin 6 is 0.28 [mm].

FIG. 9B is a diagram for explaining the experimental results.
The vertical axis of the graph represents return loss, and the horizontal axis represents frequency.
The broken line in the graph is the result of measurement with the excitation conductive plate 4 housed in the housing 2, and the solid line is the result of measurement with the cylindrical portion of the housing 2 removed.
That is, the broken line corresponds to the state in which the inverted F antenna unit 3 is housed in the housing 2, and the solid line corresponds to the state in which the inverted F antenna unit 3 is not placed in the housing 2.

As is apparent from the graph, the broken line and the solid line almost overlap each other, and both resonate at 4.5 [GHz]. That is, the characteristics of the inverted F antenna unit 3 are hardly affected by the presence or absence of the housing 2.
In the size of the timepiece device 1, the frequency resonates at 4.5 ÷ 3 = 1.5 [GHz] and is the frequency of the radio wave transmitted by the GPS satellite.

FIG. 10A is a diagram for explaining the configuration used for the simulation for examining the influence of the protrusion 51.
Metal protrusions 51 are provided on the inner peripheral surface of the housing 2 so that the protrusions 51 face the outer peripheral side of the free end side of the excitation conductive plate 4 at a predetermined distance Wc. Other dimensions are three times the values in FIG. 9A and correspond to the size of the timepiece device 1.
Using the apparatus configured as described above, the relationship between the resonance frequency of Wc and the excitation conductive plate 4 was examined.

FIG. 10B is a diagram showing a simulation result regarding the relationship between Wc and the resonance frequency of the excitation conductive plate 4.
As is apparent from the graph, the protrusion 51 is not affected by the excitation conductive plate 4 in the region where Wc is 0.5 [mm] or more, and 1.59 in the region where Wc is 0.5 [mm] or less. From about [GHz] to about 1.56 [GHz], the resonance frequency moves to the lower frequency side as Wc decreases.
This is presumably because the excitation conductive plate 4 and the protrusion 51 are close to each other so that both function as a capacitor.

According to the embodiment described above, the following effects can be obtained.
(1) The inverted F antenna unit 3 can be disposed in the housing 2 formed of a metal concave container so that the inverted F antenna unit 3 can function without being affected by the housing 2 so much.
(2) The inverted F antenna unit 3 can be installed inside the timepiece device 1, particularly the wristwatch-type timepiece device 1, and can receive radio waves from GPS satellites.
(3) The timepiece device 1 can acquire time information from radio waves from GPS satellites and correct the time. The time can be corrected anywhere in the world where GPS radio waves can be received.
(4) Even if the excitation conductive plate 4 has a curved shape along the housing 2, by making the electrical lengths on the inner peripheral side and the outer peripheral side equal, radio waves of the same frequency can be transmitted on both the inner peripheral side and the outer peripheral side. Since it can be received, the sensitivity can be improved.
(5) Depending on the shape of the excitation conductive plate 4, the frequency of the inverted F antenna unit 3 can be increased.
(6) The radio wave of the GPS satellite is circularly polarized, but in the conventional example, since the excitation conductive plate is provided along the side surface of the metal container, the sensitivity decreases when the plane of polarization is not parallel to the excitation conductive plate. Although the circularly polarized wave could not be received efficiently, the timepiece device 1 can receive the circularly polarized wave efficiently because the excitation conductive plate 4 is installed in parallel with the bottom surface of the recess 10. it can.
(7) In the conventional example, since the excitation conductive plate is provided in parallel to the side surface of the metal container, the arm side of the excitation conductive plate cannot contribute to reception of radio waves in the state where the watch is mounted on the arm. 1, any side of the ground conductive plate 7 can contribute to reception of radio waves.
(8) By providing a conductive member in the vicinity of the excitation conductive plate 4, a capacity can be loaded on the excitation conductive plate 4 and the resonance frequency of the excitation conductive plate 4 can be lowered. Thereby, the inverted F antenna unit 3 can be reduced in size.

In the embodiment described above, the case where the inverted F antenna unit 3 receives a radio wave from a GPS satellite has been described, but a radio wave from another transmission source may be used.
It is also possible to feed the transmission pin 6 and transmit radio waves from the inverted F antenna unit 3.
In addition, the direction in which the antenna is bent, the position of the feeding point, and the short-circuit point can be changed as appropriate within a range that does not break the inverted F antenna structure.
Further, the inverted F antenna unit 3 can be installed in other metal housing devices such as sensors and wirelessly communicated with these devices.

According to the embodiment described above, the following configuration can be obtained.
Since the excitation conductive plate 4 is installed, the ground conductive plate 7 functions as a first conductive plate that functions as a ground portion.
The excitation conductive plate 4 is excited by the radio wave transmitted from the GPS satellite, and is disposed in parallel with the ground conductive plate 7 at a predetermined distance, so that it is disposed in parallel with the first conductive plate. It functions as a second conductive plate for excitation.
The short-circuit pin 5 has one end connected to the ground conductive plate 7 and the other end connected to the excitation conductive plate 4 to short-circuit both of them, so that one end is connected to the first conductive plate and the other end is connected to the first conductive plate. It functions as a short-circuit member connected to the second conductive plate.
Since the transmission pin 6 is connected to the excitation conductive plate 4 and penetrates the through hole 8 of the ground conductive plate 7, it is connected to the second conductive plate with a predetermined distance from the short-circuit member, and It functions as a transmission member that penetrates the first conductive plate.
The timepiece operation unit 21 receives a signal from a GPS satellite via the transmission pin 6, acquires time information from the signal, and automatically corrects the time, so that the second conductive material is transmitted by a radio wave transmitted from a radio wave transmission source. A receiving unit is provided for detecting the excitation generated in the plate via the transmission member and receiving the signal by the radio wave.
Since the housing 2 has the recessed portion 10 and houses the inverted F antenna portion 3 composed of the above elements, the first conductive plate, the second conductive plate, the short-circuit member, and the transmission member And, it functions as a conductive casing in which a recess for housing the receiving unit is formed.
The timepiece device 1 functions as a small electronic device including these (first configuration).

  Since each of the ground conductive plates 7 is held so that the plate surface is parallel to the bottom surface of the recess 10, in the first configuration, the first conductive plate is held parallel to the bottom surface of the recess. (Second configuration).

  Since the excitation conductive plate 4 has different electrical lengths 31 and 32 with respect to the center line in the longitudinal direction with respect to the short-circuit pin 5, in the first configuration or the second configuration, the second conductive plate is The electrical length of one side with respect to the longitudinal center line of the second conductive plate is different from the electrical length of the other side (third configuration).

  Since the excitation conductive plate 4 is curved or bent along the inner periphery of the concave portion 10, in the first to third configurations, the second conductive plate is curved along the inner periphery of the concave portion, or Bent (fourth configuration).

  In addition, as described above, the timepiece device 1 includes the first conductive plate, the second conductive plate, the short-circuit member, the transmission member, the receiving unit, the first conductive plate, and the second conductive plate. A plate, the short-circuit member, the transmission member, and an element corresponding to a conductive casing in which a concave portion for accommodating the receiving portion is formed, and an inner peripheral portion of the concave portion 10 and an outer peripheral portion of the excitation conductive plate 4 The resonance frequency of the excitation conductive plate 4 can be shifted by bringing at least a portion close to each other. In this case, at least a portion of the inner peripheral portion of the recess and the outer peripheral portion of the second conductive plate is The second conductive plate is disposed within a predetermined distance where the resonance frequency shifts (fifth configuration).

  Since each of the ground conductive plates 7 is held so that the plate surface is parallel to the bottom surface of the recess 10, in the fifth configuration, the first conductive plate is held parallel to the bottom surface of the recess. (Sixth configuration).

  The portion where the resonance frequency of the excitation conductive plate 4 is shifted to the low frequency side can be the protrusion 51 provided on the inner peripheral portion of the recess 10 or the protrusion 51 provided on the excitation conductive plate 4. In the configuration described above or the sixth configuration, the portion that is equal to or less than the predetermined distance may be configured by a protrusion formed on at least one of the inner peripheral portion of the concave portion and the outer peripheral portion of the second conductive plate. Yes (seventh configuration).

  Since the protrusion 51 is formed in the same plane as the excitation conductive plate 4, in the seventh configuration, the protrusion is formed in the same plane as the second conductive plate (eighth configuration). ).

  Since the excitation conductive plate 4 is curved or bent along the inner periphery of the concave portion 10, in the fifth to eighth configurations, the second conductive plate is curved along the inner periphery of the concave portion, or Bent (9th configuration).

In recent years, electronic devices such as portable terminals and sensors have been required to be miniaturized. Therefore, how to miniaturize an antenna built in the electronic device has been a problem. In addition to downsizing, there has been a demand for higher functionality such as higher frequency.
Therefore, according to the present embodiment, the following configuration by the inverted F antenna unit 3 can be provided.

A first conductive plate that functions as a grounding portion; a second conductive plate for excitation that is arranged in parallel with the first conductive plate and curved or bent in one direction within the plate surface; A short-circuit member connected to the first conductive plate and having the other end connected to the second conductive plate, and connected to the second conductive plate at a predetermined distance from the short-circuit member, and the first conductive plate A transmission member penetrating through and a receiving unit for detecting excitation generated in the second conductive plate by the radio wave transmitted from the radio wave transmission source through the transmission member and receiving the signal by the radio wave; An antenna device is provided (tenth configuration).
In the first configuration, a conductive member for shifting the resonance frequency of the second conductive plate to a low frequency side is disposed below a predetermined distance with respect to at least a part of the outer peripheral portion of the second conductive plate. A small electronic device is provided (Eleventh Configuration).

The length of the second conductive plate is set to an element size that is approximately a quarter wavelength of the received radio wave or less, but according to this configuration, the second conductive plate is bent or bent by 4 It can be stored compactly in a space shorter than a minute wavelength.
Further, it is possible to increase the number of frequencies from the difference in the electrical length between the outer peripheral side and the inner peripheral side of the second conductive plate.
Furthermore, the second conductive plate can be reduced in size by shifting the resonance frequency.

DESCRIPTION OF SYMBOLS 1 Timepiece apparatus 2 Housing | casing 3 Reverse F antenna part 4 Excitation conductive board 5 Shorting pin 6 Transmission pin 7 Grounding conductive board 8 Through hole 10 Recessed part 11 Dial 12 Glass plate 21 Clock action part 22 Short hand 23 Long hand 31, 32 Electric length 51 protrusion

Claims (2)

A first conductive plate that functions as a grounding portion;
A second conductive plate for excitation disposed in parallel with the first conductive plate;
A short-circuit member having one end connected to the first conductive plate and the other end connected to the second conductive plate;
A transmission member connected to the second conductive plate at a predetermined distance from the short-circuit member, and penetrating the first conductive plate;
A receiving unit that detects excitation generated in the second conductive plate by a radio wave transmitted from a radio wave transmission source through the transmission member and receives a signal by the radio wave;
The first conductive plate, the second conductive plate, the short-circuit member, the transmission member, and a conductive housing formed with a recess for housing the receiving unit,
The second conductive plate is curved or bent along the inner periphery of the recess, so that the electrical length on the outer peripheral side with respect to the longitudinal center line is longer than the electrical length on the inner peripheral side. Formed, and the outer peripheral portion and the inner peripheral surface of the concave portion of the housing are arranged close to a predetermined distance or less where the resonance frequency shifts to the low frequency side ,
A small electronic device.   The small electronic device according to claim 1, wherein the first conductive plate is held in parallel with a bottom surface of the recess.

Images