JP4046192B2 - Wireless sensor transmission device, wireless sensor reception device, and wireless sensor device - Google Patents

Description

  The present invention relates to a wireless sensor transmission device, a wireless sensor reception device, and a wireless sensor device.

  Conventionally, there is known a wireless sensor transmission device in which a sensor for measuring temperature, humidity, and the like, a wireless transmission unit, and an antenna unit are integrated (see Patent Document 1). This type of wireless sensor transmitter can be spatially separated from devices that use measured values of temperature, humidity, or illuminance, so the measured values obtained by placing the wireless sensor transmitters in multiple locations, respectively Can be used in various forms, such as centralized management, and wireless sensor transmitters can be moved and carried.

  In this type of wireless sensor device, if there is no geometric limitation, an antenna structure with low loss and good radiation efficiency can be easily realized by matching the antenna pattern length to ¼ wavelength. However, in reality, this type of wireless sensor device has a strong demand for size reduction, and an ideal antenna structure having a quarter wavelength cannot be adopted.

  Under such circumstances, how to improve the radiation efficiency of the electromagnetic field radiated from the antenna becomes a critical issue, and there are still known technologies that are effective in solving such a problem. Not.

  In addition, since the conventional wireless sensor transmission device generally has a configuration in which a power source is required for a commercial power source (AC power source), the installation environment is limited in terms of securing the power source, and the range in which the commercial power source can be obtained. It was possible to install only in the environment.

  It seems that the installation problem described above can be solved once if the power source is required for the battery. However, when the wireless sensor transmission device is driven by a battery, it is technically difficult to realize both a request for size reduction of the wireless sensor device itself and a request for reduction of current consumption.

  This is because when the antenna shape is reduced due to demands for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device increases, and the wireless sensor transmission device is battery-driven. In this case, the battery life is disadvantageously terminated in a short period of half a year to one year.

When a large battery is used, the above-mentioned inconvenience can be solved, but the original demands for reduction in size, thickness and weight cannot be sufficiently met.
JP 2002-14072 A

  An object of the present invention is to provide a wireless sensor transmission device, a wireless sensor reception device, and a wireless sensor device that improve antenna directivity and improve electromagnetic radiation efficiency while reducing the size.

  Another object of the present invention is to provide a wireless sensor transmission device, a wireless sensor reception device, and a wireless sensor device that can ensure a longer battery life and continuous operation time.

  In order to solve the above-described problem, a wireless sensor transmission device according to the present invention includes a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, and an antenna unit. The circuit board includes the sensor unit, the signal processing unit, and the transmission circuit unit on one surface. The sensor unit detects a physical quantity. The signal processing unit processes a detection signal output from the sensor. The transmission circuit unit transmits a signal supplied from the signal processing unit.

  The antenna unit is helical and has a winding axis in a direction parallel to a surface in the thickness direction of the circuit board, and is a side part of an arrangement region of the sensor unit, the signal processing unit, and the transmission circuit unit. The antenna has directivity corresponding to the position on the circuit board.

  As described above, the wireless sensor transmission device according to the present invention includes a sensor unit, a signal processing unit, a transmission circuit unit, and an antenna unit, detects a physical quantity by the sensor, and detects from the sensor. Since the signal is processed by the signal processing unit, the signal supplied from the signal processing unit is supplied to the antenna unit by the transmission circuit unit, and can be radiated into the air, the physical quantity detected by the sensor is directed toward the receiving device, Wireless transmission is possible. Physical quantities to be measured include various quantities such as temperature, humidity, illuminance, acceleration, and impact.

  One of the features of the wireless sensor transmission device according to the present invention is the antenna unit. This antenna part is helical and has a winding axis in a direction parallel to the surface in the thickness direction of the circuit board. At the side of the arrangement area of the sensor part, the signal processing part and the transmission circuit part, the circuit board It is built in. With such an arrangement structure, of the electromagnetic field radiated from the antenna unit, the electromagnetic field radiated to the side of the antenna unit is transmitted to the sensor unit, the signal processing unit, the transmission circuit unit, etc. existing on the side unit. It is absorbed and attenuated by the contained conductor or conductor pattern. As a result, the antenna unit has antenna directivity in a specific direction corresponding to the position on the circuit board.

  The antenna directivity depends not only on the structure of the antenna part itself but also on the position of the antenna part on the circuit board. Therefore, the antenna directivity can be arbitrarily adjusted to some extent by selecting the position of the antenna portion on the circuit board. For example, it can be maximized in the direction intersecting the direction of the winding axis, or can be maximized in the direction of the winding axis.

  More specifically, the axial length of the antenna unit is shorter than the total length of the sensor region, the signal processing unit, and the transmission circuit unit when viewed in the direction of the winding axis, and is intermediate between the total lengths of the layout regions. The antenna directivity is maximized in the direction intersecting with the direction of the winding axis when the antenna is disposed on one side with respect to the position. When the antenna unit is arranged across the intermediate position of the entire length of the arrangement region of the sensor unit, the signal processing unit, and the transmission circuit unit, the antenna unit becomes maximum in the direction of the winding axis.

  Since the antenna conductor is helically wound, the overall length of the antenna portion can be remarkably shortened by its shape effect. Therefore, it is possible to provide a wireless sensor transmission device whose shape is significantly reduced.

  Moreover, since the antenna conductor advances in one direction parallel to the surface in the thickness direction of the support substrate, the antenna portion is combined with the circuit substrate so that the surface of the support substrate is parallel to the surface of the circuit substrate. The component penetrating the ground electrode in the high-frequency current magnetic field flowing through the antenna portion can be significantly reduced, and the generation of eddy current due to the high-frequency current magnetic field can be suppressed. Furthermore, it is possible to avoid the electromagnetic noise from getting on the antenna portion despite the fact that the whole is downsized.

  Furthermore, since the antenna portion is helical and the thickness of the support substrate is two sides of the opening, the gain of the antenna portion can be improved by controlling the area of the opening.

  As a result, both the request for downsizing of the wireless sensor transmission device itself and the request for reduction of current consumption can be realized, and the loss of the antenna unit can be reduced and the radiation efficiency of the electromagnetic field can be improved. That is, with a lower input power to the antenna unit, the communication distance is increased, and the power consumption of the circuit unit in front of the second antenna unit is reduced in a reflective manner, and the current consumption of the entire wireless sensor device is reduced. As a result, the battery life and the continuous operation time can be prolonged.

  As one specific aspect, the antenna unit includes a support substrate and an antenna conductor. The support substrate is made of an electrically insulating material, and the antenna conductor can have a structure in which the thickness of the support substrate is two sides of the opening and the winding axis is in a direction parallel to the surface in the thickness direction of the support substrate.

  As another aspect, the antenna section may be configured such that the antenna conductor is directly attached to the circuit board, the thickness of the circuit board is the two sides of the opening, and the winding axis is in a direction parallel to the surface of the circuit board.

  In the present invention, the antenna portion has a helical shape, the thickness of the support substrate is two sides of the opening, and the area of the opening can be controlled to improve the antenna portion gain.

  As a result, it is possible to realize both a request for miniaturization of the wireless sensor transmitter itself and a request for reduction of current consumption, and to achieve a reduction in the loss of the second antenna unit and an improvement in the radiation efficiency of the electromagnetic field. Can do. That is, with lower input power to the antenna unit, the communication distance is increased, and the power consumption of the circuit unit in front of the antenna unit is reflected, and the current consumption of the entire wireless sensor device is reduced. Can achieve longer battery life and continuous operation time.

  The wireless sensor transmission device according to the present invention preferably includes a battery, and the battery supplies power to the sensor unit, the signal processing unit, and the transmission circuit unit. Therefore, when installing a new wireless sensor transmitter, or when moving to any location after installation, the installation environment is not restricted by the installation environment, and can be installed freely in an environment without AC power. Can be used. That is, there is no restriction on the installation environment.

  The battery is preferably assembled on the other surface of the circuit board. That is, the sensor unit, the signal processing unit, and the transmission circuit unit are arranged on one side of the circuit board, and the battery is arranged on the other side. Therefore, a small, thin, and lightweight wireless sensor transmission device can be realized.

  The battery preferably has a circular outer periphery and is in the plane of the circuit board. According to such a configuration, the overall planar outer dimension can be reduced to a shape that is exclusively determined by the plane area of the circuit board without being affected by the outer diameter of the battery.

  By the way, when the wireless sensor transmission device is driven by a battery, it is technically difficult to satisfy both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption. For example, if the shape of the antenna portion is reduced due to the demand for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device will increase, so the battery life will be from half a year to It can cause inconvenience that it can be completed in a short period of one year.

  Of course, the battery life can be maintained for a long period of time by increasing the capacity and size of the battery, such as creating a 3.0V power supply using two AA batteries, but it is downsized. Therefore, it becomes impossible to sufficiently meet the demands for thickness reduction and weight reduction.

  Preferably, the antenna unit is provided outside the battery mounting area. According to this configuration, it is possible to suppress the generation of eddy current due to the high-frequency current magnetic field in the battery and improve the antenna efficiency.

  As another preferable aspect, the antenna unit may include a first antenna unit and a second antenna unit. In this case, the first antenna unit is electrically connected between the second antenna unit and the transmission circuit unit to match impedance between the two, and the second antenna unit transmits radio waves. Radiate.

  According to the above configuration, impedance matching is performed by the first antenna unit between the input of the second antenna unit having a high input impedance and the output of the wireless transmission unit having a low output impedance. Data can be efficiently input from the circuit unit to the second antenna unit, and a radiated electric field can be efficiently radiated from the second antenna unit.

  In addition, since impedance matching can be achieved without matching the pattern length of the second antenna unit to a quarter wavelength, a small wireless sensor transmitter that cannot employ an ideal antenna structure of a quarter wavelength. In this case, data can be efficiently input from the transmission circuit unit to the second antenna unit, and a radiated electric field can be efficiently radiated from the second antenna unit.

  As a further important effect of providing the first antenna unit separately from the second antenna unit, the manufacturing variation of the second antenna unit and the variation of the antenna efficiency due to changes in temperature and humidity are reduced. The point which can be suppressed can be mentioned.

  That is, when the second antenna unit is configured with a helical winding pattern so that it matches the output impedance of the transmission circuit unit, the substrate thickness, the width of the antenna conductor pattern formed on the substrate, and the thickness are manufactured. Due to variations and changes in the dielectric constant of the substrate due to temperature and humidity, impedance mismatching is likely to occur between the transmission circuit section and the second antenna section, and the antenna efficiency will be degraded accordingly. .

  On the other hand, when the first antenna portion is provided separately from the second antenna portion, the thickness of the substrate that supports the second antenna portion, the width and thickness of the antenna conductor pattern formed on the substrate. The antenna efficiency can be maintained by minimizing the variation in the dielectric constant of the substrate due to manufacturing variations and temperature and humidity.

  The technique for improving the antenna directivity described regarding the wireless sensor transmission device can be similarly applied to the wireless sensor reception device. This type of wireless sensor receiving device is used in combination with the above-described wireless sensor device, and includes a circuit board, a receiving antenna unit, and signal processing. The circuit board has a signal processing unit on one side, and the signal processing unit processes a signal supplied through the receiving antenna unit.

  The antenna section is helical and has a winding axis in a direction parallel to a surface in the thickness direction of the circuit board, and is assembled to the circuit board at a side portion of the arrangement area of the signal processing section. The antenna directivity corresponding to the position on the circuit board is provided.

  The wireless sensor transmission device and the reception device according to the present invention are combined with each other to constitute a wireless sensor device. The receiving device receives and processes the wireless signal transmitted from the wireless sensor transmitting device through the second antenna unit. Thereby, the physical quantity measured in the remote place can be received and displayed by the receiving device.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

1. 1 is a plan view of a wireless sensor transmission device according to the present invention, FIG. 2 is a front view of the wireless sensor transmission device shown in FIG. 1, and FIG. 3 is a wireless sensor transmission device shown in FIGS. FIG. 4 is a bottom view of the wireless sensor transmission device shown in FIGS. 1 to 3, FIG. 5 is an enlarged view of the antenna portion, and FIG. 6 is a view of the wireless sensor transmission device shown in FIGS. 1 to 5. It is an electric circuit diagram. The illustrated wireless sensor transmission device is modularized, and includes a circuit board 1, sensors 21 and 22, sensor circuits 31 and 32, a signal processing unit 4, a transmission circuit unit 5, an antenna unit 6, and a battery. 91.

  The circuit board 1 only needs to be made of an insulating material, and any of an organic insulating material, an inorganic insulating material, and a composite insulating material may be used. Moreover, the whole may be comprised with the dielectric material, and the combination of a dielectric material layer and a magnetic material layer may be sufficient.

  The sensors 21 and 22 detect physical quantities and are mounted on one surface of the circuit board 1. Physical quantities to be measured include various quantities such as temperature, humidity, illuminance, acceleration, and impact. Various sensors may be used in combination, or may be configured as a kind of sensor.

  Referring to FIG. 6, the number of sensors per module is n (n = 1, 2, 3,...). The sensor circuits 31 to 3n are individually provided in the sensors 21 to 2n. The number n is arbitrary. The illustrated embodiment shows the case where n = 2. Hereinafter, description will be made assuming that n = 2.

  The sensor circuits 31 and 32 are individually provided in the sensors 21 and 22, respectively, and convert signals detected by the sensors 21 and 22 into signals suitable for transmission and processing to the signal processing unit 4 in the subsequent stage. Is output. The sensor circuits 31 and 32 may be configured integrally with the sensors 21 and 22 as internal elements of the sensors 21 and 22. In the illustrated embodiment, the sensor circuits 31 and 32 are mounted on one surface of the circuit board 1 as a circuit independent of the sensors 21 and 22.

  The signal processing unit 4 is a circuit part that processes detection signals output from the sensors 21 and 22 or the sensor circuits 31 and 32, and is mounted on one surface of the circuit board 1.

  The transmission circuit unit 5 is a circuit that supplies a signal supplied from the signal processing unit 4 to the antenna unit 6, and is mounted on one surface of the circuit board 1.

  A ground electrode 7 is provided on the other surface of the circuit board 1. The ground electrode 7 is a so-called “solid coating” (wide area pattern), but is not formed in a portion located below the antenna unit 6. This is to avoid the adverse effect of the ground electrode 7 on the antenna unit 6.

  The battery 91 supplies power to the sensors 21 and 22, the signal processing unit 4, and the transmission circuit unit 5, and is assembled to the other surface of the circuit board 1, that is, the side where the ground electrode 7 is provided. In the illustrated embodiment, the battery 91 is a so-called “coin type” having a circular outer periphery, and the outer peripheral surface is provided on the other surface of the circuit board 1 so as not to go outside. More specifically, it is arranged inside a holder 92 made of an insulating synthetic resin or the like. One surface of the holder 92 is attached to the surface of the ground electrode 7 provided on the other surface of the circuit board 1 by means such as adhesion. Inside the holder 92, terminals 93 and 94 that are in contact with the anode and electrode of the battery 91 are provided.

  The antenna unit 6 is assembled to the circuit board 1. In the embodiment, the antenna unit 6 is provided on the periphery of the circuit board 1. The illustrated circuit board 1 has, for example, a quadrangular outer shape, and the antenna unit 6 is disposed at one corner.

  The arrangement position of the antenna unit 6 is a major feature of the present invention. The antenna unit 6 is helical and has a winding axis O1 in a direction parallel to the surface in the thickness direction of the circuit board 1, and includes sensor circuits 31, 32, sensors 21, 22, the signal processing unit 4, and transmission. It is assembled to the circuit board 1 at the side of the arrangement area of the circuit unit 5. With such an arrangement structure, among the electromagnetic fields radiated from the antenna unit 6, the electromagnetic fields radiated to the side portions of the antenna unit 6 are sensor circuits 31 and 32, sensors 21 and 22 existing on the side portions. , Receiving and attenuating action by conductors or conductor patterns included in the signal processing unit 4 and the transmission circuit unit 5. As a result, the antenna unit 6 has antenna directivity in a specific direction corresponding to the position on the circuit board 1.

  In the case of the illustrated embodiment, since the ground electrode 7 and the battery 9 are provided on the other surface of the circuit board 1, the electromagnetic field radiated from the antenna unit 6 is absorbed and attenuated by the ground electrode 7 and the battery 9. Receive. For this reason, the antenna directivity is further sharpened.

  The antenna directivity depends not only on the structure of the antenna unit 6 itself but also on the position of the antenna unit 6 on the circuit board 1. Therefore, the antenna directivity can be arbitrarily adjusted to some extent by selecting the position of the antenna unit 6 on the circuit board 1. For example, it can be maximized in a direction intersecting the direction of the winding axis O1, or can be maximized in the direction of the winding axis O1. Next, this point will be described with reference to FIGS.

  FIG. 7 is a diagram illustrating antenna directivity characteristics of the wireless sensor transmission device illustrated in FIGS. 1 to 6. The wireless sensor transmission device shown in FIGS. 1 to 6 includes sensors 21 and 22, sensor circuits 31 and 32, a signal processing unit 4, and a transmission circuit in which the axial length of the antenna unit 6 is viewed in the direction of the winding axis O <b> 1. It is shorter than the full length of the arrangement | positioning area | region of the part 5, and it is biased and arranged to one side on the basis of the intermediate position of the full length of the arrangement | positioning area | region. In this case, as shown in FIG. 7, the antenna directivity is maximized in the direction intersecting the direction of the winding axis O1.

  FIG. 8 shows another embodiment having the same basic configuration as that of the wireless sensor transmission device shown in FIGS. 1 to 6, except that the position of the antenna unit 6 is changed. In the figure, the antenna unit 6 is arranged across the intermediate position of the entire arrangement area of the sensors 21 and 22, the sensor circuits 31 and 32, the signal processing unit 4 and the transmission circuit unit 5, that is, in a substantially intermediate part. . In this case, the antenna directivity is maximized in the direction of the winding axis O1.

  FIG. 9 shows another embodiment having the same basic configuration as the wireless sensor transmission device shown in FIGS. 1 to 6, but changing the position of the antenna unit 6. Also in the case of FIG. 9, the axial length of the antenna unit 6 is based on the total length of the arrangement region of the sensors 21 and 22, the sensor circuits 31 and 32, the signal processing unit 4, and the transmission circuit unit 5 as viewed in the direction of the winding axis O1. Also, it is arranged to be biased downward (in the drawing) with reference to the intermediate position of the entire length of the arrangement region. In this case, as shown in FIG. 9, the antenna directivity is a characteristic that is the reverse of the antenna directivity in the case of FIG. 7 with respect to the winding axis O1.

  Although illustration is omitted, it is apparent that the antenna directivity can be controlled by appropriately combining the characteristics shown in FIGS. 7 to 9.

  Further, referring to FIG. 5, the antenna unit 6 is configured in a helical winding using antenna conductors 61 to 64. According to this configuration, the overall length of the antenna unit 6 can be remarkably shortened by the shape effect. Therefore, it is possible to provide a wireless sensor transmission device whose shape is significantly reduced.

  In addition, since the antenna conductors 61 to 64 advance in one direction parallel to the surface in the thickness direction of the circuit board 1, the component penetrating the ground electrode in the high-frequency current magnetic field flowing through the antenna unit 6 is significantly reduced. Generation of eddy current due to a high-frequency current magnetic field can be suppressed. Further, it is possible to avoid the electromagnetic noise from getting on the antenna unit 6 in spite of the miniaturization of the whole.

  More specifically, as shown in FIG. 5, the first conductor pieces 61 are formed on one surface of the circuit board 11 at a predetermined interval in one direction, and on the other surface, the first conductor pieces 61 and The second conductor pieces 62 are formed in the same direction at the same pitch. Then, the end portions of the first conductor piece 61 and the second conductor piece 62 are made to be helically connected by the third conductor piece 63 and the fourth conductor piece 64 penetrating the circuit board 1 in the thickness direction. Connect sequentially. Thereby, an opening surrounded by the first conductor piece 62, the third conductor piece 63, the second conductor piece 62, and the fourth conductor piece 64 is generated. The area of this opening is approximately the product XY of the effective length X of the first conductor piece 61 and the second conductor piece 62 and the effective length Y of the third conductor piece 63 and the fourth conductor piece 64. Determined.

  In order to adjust the resonance point of the impedance to the frequency for wireless transmission, the opening area, the number of turns, and the dielectric constant of the substrate material may be adjusted. The lower the radio transmission frequency, the higher the open area, the number of turns, or the dielectric constant. In order to increase the opening area, the thickness of the circuit board 1 or the floor area of the antenna forming portion may be increased, but the shape of the antenna forming portion is increased and the device shape is also increased.

  On the other hand, if the number of turns and the dielectric constant of the substrate material are increased, the impedance can be lowered without increasing the device shape. Increasing the number of turns increases the pattern length and therefore increases the conductor loss due to the pattern. However, if the relative dielectric constant (εr) of the material constituting the circuit board 1 is increased, the number of turns can be reduced. Thereby, the conductor loss by a pattern can be reduced and a shape can be reduced in size, without the loss as the antenna part 6 increasing.

  Moreover, the wireless sensor transmission device according to the present invention includes a battery 91, and the battery 91 supplies power to the sensors 21 and 22, the signal processing unit 4, and the transmission circuit unit 5. Therefore, when installing a new wireless sensor transmitter, or when moving to any location after installation, the installation environment is not restricted by the installation environment, and can be installed freely in an environment without AC power. Can be used. That is, there is no restriction on the installation environment.

  In the wireless sensor transmission device according to the present invention, the battery 91 is assembled to the other surface (ground electrode side) of the circuit board 1. That is, the sensor 21, 22, the signal processing unit 4 and the transmission circuit unit 5 are arranged on one side of the circuit board 1, and the battery 91 is arranged on the other side. Therefore, a small, thin, and lightweight wireless sensor transmission device can be realized.

  The battery 91 preferably has a circular outer periphery and is in the plane of the circuit board 1. According to such a configuration, the overall planar outer dimension can be reduced to a shape determined solely by the plane area of the circuit board 1 without being affected by the outer diameter of the battery 91.

  By the way, when the wireless sensor transmission device is driven by a battery, it is technically difficult to satisfy both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption. For example, when the shape of the antenna unit 6 is reduced due to demands for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device increases, so the battery life is half a year. It can cause the inconvenience of ending in a short period of ~ 1 year.

  Of course, the battery life can be maintained for a long period of time by increasing the capacity and size of the battery, such as creating a 3.0V power supply using two AA batteries, but it is downsized. Therefore, it becomes impossible to sufficiently meet the demands for thickness reduction and weight reduction.

  Furthermore, in order to realize both the request for downsizing of the wireless sensor transmission device itself and the request for reduction in current consumption, the communication distance must be increased with lower input power to the antenna unit 6. . For this purpose, it is necessary to reduce the loss of the antenna unit 6 and increase the radiation efficiency of the electromagnetic field.

  Regarding the above requirement, in the present invention, the antenna conductors 61 to 64 wind in one direction parallel to the surface of the circuit board 1. It can be remarkably reduced and generation of eddy current due to a high-frequency current magnetic field can be suppressed. Further, it is possible to avoid the electromagnetic noise from getting on the antenna unit 6 in spite of the miniaturization of the whole.

  Moreover, since the antenna portion 6 is helical and the thickness of the circuit board 1 is two sides of the opening, the antenna gain can be improved by controlling the area of the opening.

  As a result, both the request for downsizing the wireless sensor transmission device itself and the request for reduction in current consumption can be realized, and the loss of the antenna unit 6 can be reduced and the radiation efficiency of the electromagnetic field can be improved. . That is, with a lower input power to the antenna unit 6, the communication distance is increased, the power consumption of the circuit unit provided in the front stage of the antenna unit 6 is reduced, and the current consumption of the entire wireless sensor device is reduced. Longer battery life and continuous operation time can be achieved.

  The antenna unit 6 is preferably provided outside the mounting area of the battery 91. In addition, it is preferable that an electrical element other than the antenna unit 6, for example, a conductor pattern or other components is not disposed in the occupied area of the antenna unit 6. According to such a configuration, it is possible to avoid interference of electric signals and electromagnetic fields with respect to the antenna unit 6 to suppress the generation of noise, and to reduce eddy current leakage and improve antenna gain.

  10 is a plan view showing another embodiment of the wireless sensor transmission device according to the present invention, and FIG. 11 is a partial sectional view of the wireless sensor transmission device shown in FIG. This embodiment is characterized in that the support substrate 60 that supports the antenna conductors 61 to 64 is independent from the circuit substrate 1 for the wireless sensor transmission device. The antenna unit 6 is mounted on one surface of the circuit board 1 on which the sensors 21 and 22, the signal processing unit 4, and the transmission circuit unit 5 are mounted.

  According to this embodiment, the same effect as the embodiment shown in FIGS. 1 to 6 can be obtained, and the circuit board 1 does not affect the opening area of the antenna portion 6, so that the thickness of the circuit board 1 is reduced. As a result, the entire apparatus can be thinned. Since the sensors 21 and 22, the signal processing unit 4, and the transmission circuit unit 5 are originally mounted on one surface of the circuit board 1 on which the antenna unit 6 is mounted, the antenna unit 6 is mounted on one surface of the circuit board 1. Even if it does, the thickness of the whole apparatus does not increase.

  In addition, since the support substrate 60 that supports the antenna conductors 61 to 64 is independent from the circuit board 1, the support substrate 60 is a dielectric material having a relative dielectric constant higher than that of the dielectric material constituting the circuit board 1. The antenna gain can be improved while reducing the size. The antenna gain can also be adjusted by adjusting the dielectric constant of the dielectric material constituting the support substrate 60. Although illustration is omitted, it is needless to say that the antenna arrangement shown in FIGS. 8 and 9 can be taken.

  12 is a plan view showing still another embodiment of the wireless sensor transmission device according to the present invention, FIG. 13 is a partial sectional view of the wireless sensor transmission device shown in FIG. 12, and FIG. 14 is shown in FIGS. It is a bottom view of a wireless sensor transmitter. The feature of this embodiment resides in that the antenna portion 6 is provided over almost the entire length along one side of the circuit board 1. The antenna unit 6 is provided directly on the circuit board 1. The ground electrode 7 is not provided in a portion corresponding to the antenna unit 6 (see FIG. 14).

FIG. 15 is a diagram illustrating antenna directivity characteristics of the wireless sensor transmission device illustrated in FIGS. 12 to 14. In this case, the antenna directivity is maximized in the direction orthogonal to the winding axis O1.
The ground electrode 7 functions as the ground potential of the sensors 21 and 22, the sensor circuits 31 and 32, the signal processing circuit 4, the transmission circuit unit 5, and the antenna unit 6, but contributes to the radiation efficiency of the antenna.

  The radiation electric field intensity from the antenna unit 6 tends to depend on the area of the ground electrode 7. As the area of the ground electrode 7 is larger, the radiation electric field tends to increase.

FIG. 15 shows the radiated electric field intensity detected on the surface of the ground electrode 7 and in the direction of the winding axis O1 (antenna opening direction). The measurement was performed in a 3 m anechoic chamber. The measured values are as follows.
In addition, the data of FIGS. 7-9 were obtained by the same measuring method.
Ground electrode area 20 × 20mm 20 × 17mm 20 × 15mm
Radiant electric field strength 57 dBμV / m 53 dBμV / m 51 dBμV / m
Thus, the electric field intensity radiated from the wireless sensor transmission device tends to increase as the area of the ground electrode 7 increases. For this reason, in the embodiments of FIGS. 12 to 14, the ground electrode 7 is made as large as possible, and the distance between the ground electrode 7 and the antenna unit 6 is made as small as possible. In the example, the interval was 0.2 mm. The conductor pattern on the surface of the circuit board 1 is formed by a method such as etching, and the lower limit is set in consideration of manufacturing tolerances in this method.

  Referring to FIG. 15, the directivity of the radiation electric field is influenced not only by the arrangement and configuration of the antenna unit 6 but also by the ground electrode 7 and the battery 91. The directivity can be generally controlled by the configuration of the antenna unit 6 as long as a quarter wavelength of the transmission frequency falls within the shape of the antenna unit 6. If not, the dielectric constant of the metal or material such as the adjacent ground electrode 7 is likely to be affected.

  In this embodiment, the transmission frequency is 315 MHz, and one wavelength is sufficiently long as about 30 cm. Compared with this, the shape of the antenna is as small as about 18 × 3 mm, and the size of the wireless sensor transmission device is also 25 ×. It is about 25 mm, and the quarter wavelength is sufficiently large with respect to the wireless sensor transmitter. For this reason, the radiation electric field is mainly affected by the ground electrode 7 and the electrode of the battery 91 which are the electrodes having the largest area in the wireless sensor transmission device.

  As a result, as shown in FIG. 15, the directivity is shown so as to show the strongest radiation electric field intensity in the direction of 90 degrees with respect to the opening of the antenna unit 6, that is, the direction of the winding axis O1.

  16 is a plan view showing still another embodiment of the wireless sensor transmission device according to the present invention, and FIG. 17 is a partial sectional view of the wireless sensor transmission device shown in FIG. The feature of this embodiment is that the antenna portion 6 supported by the support substrate 60 is provided over almost the entire length along one side of the circuit board 1.

  FIG. 18 is a diagram illustrating antenna directivity characteristics of the wireless sensor transmission device illustrated in FIGS. 16 and 17. As shown in the figure, the wireless sensor transmitters shown in FIGS. 16 and 17 exhibit the antenna directivity that is maximum in the direction that coincides with the direction of the winding axis O1.

  As described above, in the wireless sensor transmission device of the present invention, the directivity of the antenna unit 6 varies greatly depending on the arrangement and shape of the antenna unit 6 regardless of the helical winding. This is because it is influenced by the nearby conductor pattern such as the ground electrode 7, the metal part of the battery 91, and the electrically insulating material of the circuit board 1. In the present embodiment, the circuit board 1 is composed of FR4. In the case of FR4, the relative dielectric constant is about 4 to 5, which is sufficiently higher than that in the case of air (1.0). This point can be seen from a comparison between FIG. 15 and FIG.

  Therefore, if the directivity of the radiated electric field from the wireless sensor transmitter is clarified in advance, the installation can be optimized. If the installation of the wireless sensor device is arranged so as to radiate an electric field in the direction of strong directivity, the communication distance can be increased. If the wireless sensor device is designed to have a certain communication distance, This leads to a reduction in the current consumption of the battery, which extends the life of the battery and, in turn, improves the continuous operation time of the wireless sensor device. The same can be said for the wireless sensor receiver. If both the wireless sensor transmission device and the wireless sensor reception device have the same directivity, the effect is further doubled.

  FIG. 19 is an electric circuit diagram showing another embodiment of the wireless sensor transmission device according to the present invention. In the figure, parts corresponding to those shown in FIG. 6 are given the same reference numerals, and redundant description is omitted.

  The feature of this embodiment is that the antenna unit 6 includes a first antenna unit 601 and a second antenna unit 602. The first antenna unit 601 is electrically connected between the second antenna unit 602 and the transmission circuit unit 5, and matches the impedance between them.

  According to the above configuration, impedance matching by the first antenna unit 601 is performed between the input of the second antenna unit 602 having a high impedance and the output of the transmission circuit unit 5 having a low output impedance. The data can be efficiently input from the transmission circuit unit 5 to the second antenna unit 602, and the radiated electric field can be efficiently radiated from the second antenna unit 602.

  In addition, since impedance matching can be achieved without matching the pattern length of the second antenna portion 602 to ¼ wavelength, a small-sized wireless sensor transmitter that cannot adopt an ideal antenna structure of ¼ wavelength. In this case, data can be efficiently input from the transmission circuit unit 5 to the second antenna unit 602, and a radiated electric field can be efficiently radiated from the second antenna unit 602.

  In order to adjust the resonance point of the impedance to the frequency for wireless transmission, the opening area, the number of turns, and the dielectric constant of the substrate material may be adjusted. The lower the radio transmission frequency, the higher the open area, the number of turns, or the dielectric constant. In order to increase the open area, the thickness of the circuit board 1 or the floor area of the second antenna portion 602 formation portion may be increased, but the shape of the second antenna portion 602 formation portion also increases, and the device shape Also grows.

  On the other hand, if the number of turns and the dielectric constant of the substrate material are increased, the impedance can be lowered without increasing the device shape. Increasing the number of turns increases the pattern length and therefore increases the conductor loss due to the pattern. However, if the relative dielectric constant (εr) of the material constituting the circuit board 1 is increased, the number of turns can be reduced. Thereby, the conductor loss by a pattern can be reduced and a shape can be reduced in size, without increasing the loss as the 2nd antenna part 602. FIG.

As an example, the relationship between the relative dielectric constant of the substrate and the shape of the second antenna portion 602 is shown below.
Relative permittivity shape (length x width x thickness)
εr = 4 18 × 3 × 2mm
εr = 20 9 × 3 × 2mm
εr = 80 3 × 3 × 2 mm
As described above, the shape of the second antenna portion 602 can be reduced by the relative dielectric constant of the material to be formed.

  In the present invention, since the first antenna unit 601 is combined with the second antenna unit 602 having the above advantages, impedance matching between the second antenna unit 602 and the transmission circuit unit 5 is achieved, and the antenna efficiency is improved. Can be further improved.

  For example, when the output impedance of the transmission circuit unit 5 is set to 50Ω and the input impedance of the second antenna unit 602 is 100Ω, the input impedance of the first antenna unit 601 is set to 50Ω and the output impedance is By setting to 100Ω, almost perfect impedance matching can be achieved between the transmission circuit unit 5 and the second antenna unit 602.

  That is, with respect to the impedance matching between the transmission circuit unit 5 and the second antenna unit 602, a certain portion of the impedance mismatch generated between the two is supplemented by the first antenna unit 601. For this reason, in this embodiment, the area required for the second antenna unit 602 configured by the helical pattern is half that required when the first antenna unit 601 is not provided.

  As a result, both the request for downsizing of the wireless sensor transmission device itself and the request for reduction of current consumption are realized, and the second antenna unit 602 is reduced in loss and electromagnetic radiation efficiency is improved. be able to. That is, a low input power to the second antenna unit 602 increases the communication distance, and reflectively reduces the power consumption of the circuit unit in front of the second antenna unit 602, thereby consuming the entire wireless sensor device. It is possible to achieve a reduction in current and, in turn, an increase in battery life and continuous operation time.

  As a further important effect of providing the first antenna unit 601 separately from the second antenna unit 602, the manufacturing efficiency of the second antenna unit 602 and the antenna efficiency due to temperature and humidity changes. The point which can suppress the fluctuation | variation of is mentioned. Manufacturing variations, changes in temperature and humidity cause impedance mismatch between the transmission circuit unit 5 and the second antenna unit 602, resulting in an increase in current consumption of the transmission circuit unit 5 and deterioration in battery life. As a sensor transmission device, the continuous operation time is reduced. In addition, the communication distance is deteriorated.

  That is, when the second antenna unit 602 is entirely configured with a helical winding pattern so as to match the output impedance of the transmission circuit unit 5, the substrate thickness, the width of the antenna conductor pattern formed on the substrate, Due to variations in thickness and variations in the dielectric constant of the substrate due to temperature and humidity, impedance mismatching is likely to occur between the transmission circuit unit 5 and the second antenna unit 602, and the antenna efficiency is accordingly increased. It will deteriorate.

  On the other hand, according to the present invention in which the first antenna unit 601 is provided separately from the second antenna unit 602, manufacturing variations in the substrate thickness, the width and thickness of the antenna conductor pattern formed on the substrate are provided. In addition, the change in the dielectric constant of the substrate due to temperature and humidity can be minimized, and the antenna efficiency can be maintained.

  In the embodiment of FIG. 19, the first antenna unit 601 is composed of a circuit composed of one inductor L11 and two capacitors C11 and C12. As such an LC circuit component, a surface mount component displayed as 1005 (1 mm × 0.5 mm) or 1608 (1.6 mm × 0.8 mm) can be used. For this reason, it is hardly affected by installation environment conditions, manufacturing tolerances of the substrate, and the like.

  FIG. 20 is an electric circuit diagram showing another embodiment of the wireless sensor transmitter according to the present invention. In the figure, parts corresponding to those shown in FIG. 19 are given the same reference numerals, and redundant description is omitted. In the case of FIG. 20, as the first antenna portion 601, a surface mount type component in which a helical pattern similar to the second antenna portion 602 is formed on a ceramic block can be used. The size of the ceramic block can be about 2 mm, and is hardly affected by installation environment conditions and substrate manufacturing tolerances. For this reason, even when the width and thickness of the pattern formed on the substrate, the thickness of the substrate, and the like change due to manufacturing variations and the input impedance of the second antenna portion 602 changes, the first antenna portion The matching state between the input of the second antenna unit 602 and the output impedance of the transmission circuit unit 5 due to 601 is not substantially affected. The same is true for the influence of εr of the substrate over time.

  The second antenna unit 602 is provided outside the battery 91 mounting area. In addition, it is preferable that an electrical element other than the second antenna unit 602, for example, a conductor pattern or other components is not disposed in the occupied area of the second antenna unit 602. According to such a configuration, it is possible to avoid the interference of electric signals and electromagnetic fields with respect to the second antenna unit 602, suppress the generation of noise, reduce eddy current leakage, and improve the antenna gain.

  21 is a plan view of the wireless sensor transmission device illustrated in FIG. 19 or FIG. 20, and FIG. 22 is a partial cross-sectional view of the wireless sensor transmission device illustrated in FIG. Constituent parts appearing in the above-described drawings are given the same reference numerals, and redundant description is omitted. The first antenna portion 601 is attached to the upper side of the circuit board 1, and the second antenna portion 602 is provided over almost the entire length along one side of the circuit board 1, as in FIGS. 16 and 17. It is in the point. The antenna directivity characteristic of the second antenna unit 602 is as shown in FIG.

2. Wireless Sensor Device FIG. 23 is a block diagram showing a configuration of a wireless sensor device according to the present invention. In the figure, parts corresponding to the constituent parts shown in the above-mentioned drawings are given the same reference numerals. As illustrated, the wireless sensor transmission devices 101 to 10m according to the present invention are combined with the reception device 8 to constitute a wireless sensor device. In the illustrated embodiment, m wireless sensor transmitters 101 to 10m are provided. These shall be arrange | positioned in a mutually different position. The number m (m = 1, 2, 3,...) Of the wireless sensor transmission devices 101 to 10 m may be arbitrary.

  The receiving device 8 includes a receiving antenna unit 81, a receiving circuit 82, a signal processing circuit 83 configured by a CPU or the like, and a display unit 84 such as a display. In addition, a conversion unit for interfacing with a personal computer may be provided. The reception device 8 receives the wireless signal transmitted from the wireless sensor transmission devices 101 to 10 m by the reception antenna unit 81 and the reception circuit 82 and processes them by the signal processing device 83. Then, the processing result is displayed on the display unit 84. Thereby, the physical quantity measured in the remote place can be received and displayed by the receiving device 8.

  FIG. 24 is a block diagram showing another configuration of the wireless sensor device according to the present invention. In the figure, parts corresponding to the constituent parts shown in the above-mentioned drawings are given the same reference numerals. As shown in the drawing, in the illustrated embodiment, m receiving devices 801 to 80m are provided for one wireless sensor transmitting device. These shall be arrange | positioned in a mutually different position. The number m (m = 1, 2, 3,...) Of the receiving devices 801 to 80m may be arbitrary.

  Each of the reception devices 801 to 80m receives the radio signal transmitted from the wireless sensor transmission device 10 by the reception antenna unit 81 and the reception circuit 82, and processes the signal by the signal processing device 83. Then, the processing result is displayed on the display unit 84. Thereby, the physical quantity measured in the remote place can be individually received and displayed by the receiving devices 801 to 80m installed in different places.

3. Wireless sensor receiver The wireless sensor device according to the present invention is based on the combination of the wireless sensor transmitter shown in FIGS. 1 to 22 and the wireless sensor receiver, and the wireless sensor receiver has its function. Although there is no limitation as long as the above is satisfied, the antenna technology used in the wireless sensor transmission device can also be applied to wireless sensor reception. FIG. 25 is a plan view showing the configuration of such a wireless sensor receiver, and FIG. 26 is a front view of the wireless sensor receiver shown in FIG.

  In this embodiment, the receiving antenna portion 81 supported by the support substrate 60 is provided along the one side of the circuit board 1 over almost the entire length thereof. The receiving antenna unit 81 has a helical structure as shown in FIGS. 15 and 16, and exhibits the antenna directivity that is maximum in the direction that coincides with the direction of the winding axis O2. In addition, it goes without saying that the antenna structure and arrangement shown in FIGS.

  Accordingly, the wireless sensor device according to the present invention includes a combination of the wireless sensor transmission device shown in FIGS. 1 to 22 and the wireless sensor reception device, and a wireless sensor transmission device different from that shown in FIGS. And a combination of the wireless sensor receiver shown in FIGS. 25 and 26, and a combination of the wireless sensor transmitter shown in FIGS. 1 to 22 and the wireless sensor receiver shown in FIGS. Exists.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

It is a top view of the wireless sensor transmitter concerning the present invention. It is a front view of the wireless sensor transmitter shown in FIG. FIG. 3 is a partially broken bottom view of the wireless sensor transmission device shown in FIGS. 1 and 2. FIG. 4 is a bottom view of the wireless sensor transmission device shown in FIGS. 1 to 3. It is an enlarged view of the antenna part 6 part in the radio | wireless sensor transmission apparatus shown in FIGS. FIG. 6 is an electric circuit diagram of the wireless sensor transmission device shown in FIGS. It is a figure which shows the antenna directivity characteristic of the radio | wireless sensor transmission apparatus shown in FIGS. FIG. 7 is a diagram illustrating antenna directivity characteristics when the position of the antenna unit 6 is changed although it has the same basic configuration as the wireless sensor transmission device illustrated in FIGS. 1 to 6. FIG. 7 is a diagram illustrating antenna directivity characteristics when the position of the antenna unit 6 is changed although it has the same basic configuration as the wireless sensor transmission device illustrated in FIGS. 1 to 6. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the wireless sensor transmitter shown in FIG. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the radio | wireless sensor transmission apparatus shown in FIG. FIG. 14 is a bottom view of the wireless sensor transmission device shown in FIGS. 12 and 13. It is a figure which shows the antenna directivity characteristic of the radio | wireless sensor transmission apparatus shown in FIGS. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the wireless sensor transmitter shown in FIG. FIG. 18 is a diagram illustrating antenna directivity characteristics of the wireless sensor transmission device illustrated in FIGS. 16 and 17. It is an electric circuit diagram which shows another Example of the wireless sensor transmitter which concerns on this invention. It is an electric circuit diagram which shows another Example of the wireless sensor transmitter which concerns on this invention. FIG. 21 is a plan view of the wireless sensor transmission device illustrated in FIG. 19 or 20. FIG. 22 is a partial cross-sectional view of the wireless sensor transmission device illustrated in FIG. 21. It is a block diagram which shows the structure of the wireless sensor apparatus which concerns on this invention. It is a block diagram which shows another structure of the wireless sensor apparatus which concerns on this invention. It is a top view which shows the structure of a wireless sensor receiver. It is a front view of the wireless sensor receiver shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 21, 22 Sensor 31-3n Sensor circuit 4 Signal processing part 5 Transmission circuit part 6 Antenna part 60 Support board 61-64 Antenna conductor 91 Battery

Claims (13)

A wireless sensor transmission device including a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, and an antenna unit,
The circuit board has the sensor unit, the signal processing unit, and the transmission circuit unit on one surface,
The sensor unit detects a physical quantity,
The signal processing unit is a circuit that processes a detection signal output from the sensor,
The transmission circuit unit is a circuit that transmits a signal supplied from the signal processing unit,
The antenna unit includes a helical antenna conductor having a thickness of the circuit board as two sides of the opening and having a winding axis in a direction parallel to the surface of the circuit board, the sensor unit, the signal processing unit, and the At the side of the arrangement area of the transmission circuit portion , the axial position is shorter than the total length of the arrangement area as viewed in the direction of the winding shaft, and the intermediate position of the total length of the arrangement area is assembled to the circuit board. , With the antenna directivity in the direction intersecting with the direction of the winding axis,
Wireless sensor transmitter. A wireless sensor transmission device including a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, and an antenna unit,
The circuit board has the sensor unit, the signal processing unit, and the transmission circuit unit on one surface,
The sensor unit detects a physical quantity,
The signal processing unit is a circuit that processes a detection signal output from the sensor,
The transmission circuit unit is a circuit that transmits a signal supplied from the signal processing unit,
The antenna unit includes a helical antenna conductor having a thickness of the circuit board as two sides of the opening and having a winding axis in a direction parallel to the surface of the circuit board, the sensor unit, the signal processing unit, and the At the side of the arrangement area of the transmission circuit portion, the intermediate position of the arrangement area is straddled across the intermediate position of the arrangement area , and the axial length is the total length of the arrangement area as viewed in the direction of the winding shaft. Shorter, with antenna directivity in the direction of the winding axis,
Wireless sensor transmitter. 3. The wireless sensor transmission device according to claim 1, further comprising a ground electrode, wherein the ground electrode is configured in a solid shape in the entire surface of the circuit board except the antenna portion. wireless sensor transmitting device are. The wireless sensor transmission device according to any one of claims 1 to 3, comprising a battery, wherein the battery supplies power to the sensor unit, the signal processing unit, and the transmission circuit unit. A wireless sensor transmission device assembled on the other surface of the circuit board . 5. The wireless sensor transmission device according to claim 4, wherein the antenna unit is provided outside a mounting area of the battery . 6. 6. The wireless sensor transmission device according to claim 4, wherein the battery has a circular outer periphery and is in a plane of the circuit board . 7. A wireless sensor transmission device according to any one of claims 1 to 6,
The antenna unit includes a first antenna unit and a second antenna unit,
The first antenna unit is electrically connected between the second antenna unit and the transmission circuit unit, and matches the impedance between the two,
The second antenna unit radiates radio waves;
Wireless sensor transmitter. The wireless sensor transmission device according to claim 7, wherein the first antenna unit is configured by an electronic component including an inductor . 8. The wireless sensor transmission device according to claim 7, wherein the first antenna unit is configured by an electronic component including an inductor and a capacitor, and is mounted on the one surface of the circuit board. Transmitter device. A wireless sensor receiving device including a circuit board, a receiving antenna unit, and a signal processing unit,
The circuit board has the signal processing unit on one surface,
The signal processing unit is a part that processes a signal supplied through the receiving antenna unit,
The antenna section includes a helical antenna conductor having a thickness of the circuit board as two sides of the opening and having a winding axis in a direction parallel to the surface of the circuit board, and a side portion of the arrangement area of the signal processing section The axial length is shorter than the total length of the placement region viewed in the direction of the winding axis, and is biased to one side with respect to the intermediate position of the total length of the placement region. Arranged and having antenna directivity in a direction intersecting with the direction of the winding axis,
Wireless sensor receiver. A wireless sensor receiving device including a circuit board, a receiving antenna unit, and a signal processing unit,
The circuit board has the signal processing unit on one surface,
  The signal processing unit is a part that processes a signal supplied through the receiving antenna unit,
The antenna section includes a helical antenna conductor having a thickness of the circuit board as two sides of the opening and having a winding axis in a direction parallel to the surface of the circuit board, and a side portion of the arrangement area of the signal processing section The axial length of the arrangement area is shorter than the total length of the arrangement area as viewed in the direction of the winding axis. With antenna directivity,
Wireless sensor receiver. A wireless sensor device including a wireless sensor transmission device and a reception device,
The wireless sensor transmission device is the one described in any one of claims 1 to 9,
The receiving device includes a receiving antenna unit and a signal processing unit, and receives and processes a radio signal transmitted from the wireless sensor transmitting device through the receiving antenna unit.
Wireless sensor device. The wireless sensor device according to claim 12, wherein the receiving device is the one described in claim 10 or 11.

Images