JP2002031616A - Transponder for detecting humidity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transponder for detecting a humidity which can obtain humidity information wirelessly. SOLUTION: Base electrodes 41 and 42 shaped like comb teeth are arranged adjacently to be meshed with each other. An electric resistance layer 43 is formed of a material having a high electric resistance including carbon onto the electrodes, whereby a humidity-detecting part 40 is constituted. The humidity in a surrounding space of the humidity-detecting part 40 permeates the electric resistance layer 43. As a result, an electric resistance between the base electrodes 41 and 42 changes correspondingly to the humidity. Moreover an electrical signal corresponding to the electric resistance value between the base electrodes 41 and 42 is supplied as humidity information to a transponder body 30. The transponder body 30 transmits a response signal including the humidity information. A permeability and a diverging efficiency for the humidity are improved by setting a thickness of the electric resistance layer to be 50 μm or smaller. Power consumption when a sensor operates is reduced by forming the electric resistance layer 43 of the material having the high electric resistance including carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity detecting transponder for wirelessly transmitting humidity information detected by a sensor.

[0002]

2. Description of the Related Art Conventionally, in order to detect humidity at a remote location, it has been necessary to arrange an electrical humidity sensor at a location to be measured and extend a signal line from the sensor to the main body of the measuring apparatus. .

For example, in a humidity measuring device disclosed in Japanese Patent Application Laid-Open No. Hei 6-3307, a humidity sensor 22 having a pair of electrodes 22a connected by conductive paper 22b is provided in a container 21 as shown in FIG. And the surrounding air is blown into the container by the blower 23 to make the humidity in the container the same as the surroundings. The electrode 22a of the temperature sensor 22 is connected to a resistance measuring device 24 by a measuring lead (conductive wire) 26. The value measured by the resistance measuring device 24 is recorded by the recorder 25. The conductive paper 22b is a mixture of wholly aromatic polyamide fibers and carbon fibers.

According to the above configuration, when moisture in the air permeates the conductive paper 22b, the degree of fiber expansion changes, and the contact resistance between carbon fibers changes. Thus, the electric resistance between the pair of electrodes 22a changes according to the humidity. The humidity can be measured by measuring the electric resistance value with the resistance measuring device 24.

[0005]

However, as described above, in the conventional electric humidity measuring device, the humidity sensor 2 is used.
2 and the resistance measuring device 24 must be connected by the measuring lead 26, so that the installation of the device is troublesome and the humidity to the place inside the rotating body or inside the moving body where it is difficult to provide the measuring lead 26 is required. The installation of the sensor 22 was difficult.

An object of the present invention is to provide a humidity detecting transponder capable of acquiring humidity information wirelessly in view of the above problems.

[0007]

According to the present invention, there is provided a transponder body having transmitting / receiving means for transmitting a response signal when an inquiry signal is received wirelessly, a humidity sensor, Response signal generation means for generating the response signal including humidity information detected by the humidity sensor, wherein the humidity sensor includes a substrate formed of an insulating plate or film, and a substrate formed on the substrate. A pair of base electrodes; an electric resistance layer having a high electric resistance and having a thickness set to 50 μm or less provided on the substrate surface so as to connect the pair of base electrodes; Means for supplying an electric signal corresponding to an electric resistance value between the electrodes to the transponder main body as the humidity information.

According to the humidity detecting transponder, moisture in the space around the substrate penetrates into the electric resistance layer, and the electric resistance between the pair of base electrodes changes according to the humidity in the surrounding space. Further, an electric signal corresponding to an electric resistance value between the pair of base electrodes is supplied to the transponder main body as humidity information. Accordingly, the transponder main body transmits a response signal including humidity information according to an electric resistance value between the pair of base electrodes. Also,
If the thickness of the electric resistance layer is set to 50 μm or more, the permeability of the surrounding moisture decreases, the change in electric resistance becomes small, and the electric resistance layer is easily cracked. However, since the thickness of the electric resistance layer is set to 50 μm or less, the permeability and divergence of moisture are improved, and the electric resistance value changes according to humidity. The thickness of the electric resistance layer is preferably about 20 μm. Further, since the electric resistance layer contains carbon and has high electric resistance, power consumption during operation of the sensor is small.

According to a second aspect of the present invention, there is provided the humidity detecting transponder according to the first aspect, wherein the electric resistance layer contains carbon.

According to the humidity detecting transponder, since the electric resistance layer contains carbon, the electric resistance layer can be small and have a high resistance value.

According to a third aspect of the present invention, in the humidity detecting transponder according to the first or second aspect, the base electrode is formed in a comb-like shape, and the comb-like portions mesh with each other in close proximity to each other. In this manner, a transponder for detecting humidity which is arranged to face each other is proposed.

According to the humidity detecting transponder, since the base electrodes are formed in a comb shape and are arranged close to each other so as to mesh with each other, the length of the opposing portion of the pair of base electrodes can be reduced within a small area. Can be set large. Thereby, the detection accuracy in high humidity is improved. That is, when the length of the facing portion of the base electrode is short, the detection error is increased due to the spots of moisture, but when the length of the facing portion is set to be large, even if the spot of moisture is generated, each Since the average value of the resistance values of the spots is detected, the detection error is reduced, and the detection accuracy is improved.

According to a fourth aspect of the present invention, in the humidity detecting transponder according to any one of the first to third aspects, the electric resistance value of the electric resistance layer between the pair of base electrodes is 1 k at an average humidity. A humidity detection transponder set to a value equal to or higher than ohms is proposed.

According to the humidity detecting transponder, since the electric resistance is set to a high resistance of 1 kΩ or more at the average humidity, the power consumption during the operation of the sensor is reduced and the electric resistance due to the penetration of moisture is reduced. The rate of change of the value increases, and the detection accuracy of the humidity value improves.

According to a fifth aspect of the present invention, in the transponder for detecting a humidity according to any one of the first to fourth aspects, the electric resistance layer is formed on the substrate so as to cover the pair of base electrodes. We propose a transponder for detecting humidity.

According to the humidity detecting transponder, since the electric resistance layer covers the pair of base electrodes, the peripheral portion where the electric resistance layer is likely to be chipped or peeled is located outside the base electrode. In addition, a change in the resistance value between the pair of base electrodes due to chipping or peeling of the electric resistance layer can be extremely reduced.

According to a sixth aspect of the present invention, in the transponder for detecting humidity according to any one of the first to fifth aspects, the electric resistance layer is formed by blending a water-absorbing polymer with an organic polymer electrolyte. We propose a transponder for detecting humidity consisting of a polymer electrolyte composite membrane containing carbon.

According to the transponder for detecting humidity, since the surrounding moisture easily penetrates and diffuses into the electric resistance layer by the water-absorbing polymer, the responsiveness of the electric resistance change to the surrounding moisture is improved.

According to a seventh aspect of the present invention, in the transponder for detecting a humidity according to any one of the first to sixth aspects, the transmitting and receiving means transmits and receives the interrogation signal and the response signal by electromagnetic waves, and transmits and receives the interrogation signal by an interrogation signal. An induced electromotive force induced in the antenna of the transmitting / receiving means, an energy converting means for converting the induced electromotive force into power for driving the transmitting / receiving means and supplying the power to the transmitting / receiving means, and a power supply connection terminal for connecting a power supply such as a storage battery; A humidity detection transponder comprising: a power supply control unit that supplies power supplied from the power supply connection terminal to the transmission / reception unit based on power supply from energy conversion unit.

According to the humidity detecting transponder, the induced electromotive force induced in the antenna of the transmitting / receiving means when the interrogation signal is received is converted by the energy converting means into electric power for driving the transmitting / receiving means, and Supplied to Further, based on the power supply from the energy conversion unit, the power is supplied from the power supply connection terminal by the power supply control unit during the power supply or during a part of the power supply. Power is supplied to the transmitting and receiving means.

According to an eighth aspect of the present invention, in the humidity detecting transponder according to the seventh aspect, the power supply control means supplies the power supplied from the power supply connection terminal to the transmission / reception means only when the response signal is transmitted. We propose a transponder for detecting humidity.

According to the transponder for detecting humidity, at the time of receiving the interrogation signal, the induced electromotive force induced in the antenna by the energy conversion means is converted into the power for driving the transmission / reception means, and the transmission / reception means is driven by the power. You. Further, at the time of transmitting the response signal, the transmitting / receiving means is driven by the power supplied from the power supply.

According to a ninth aspect of the present invention, there is provided the humidity detecting transponder according to the seventh aspect, wherein the energy conversion means includes a rectifier circuit.

According to the humidity detecting transponder, the energy conversion means comprises a rectifying circuit, and the induced electromotive force induced in the antenna is converted into a direct current by the rectifying circuit and supplied to the transmitting / receiving means.

According to a tenth aspect of the present invention, in the humidity detecting transponder according to the seventh aspect, the power supply control means includes a switching transistor that is turned on based on power supply from the energy conversion means. Propose a transponder.

According to the humidity detecting transponder, when an induced electromotive force due to the interrogation signal is generated in the antenna, power is output from the energy conversion means, and the switching transistor is turned on from the off state based on the supply of the power. The power supplied from the power supply connection terminal via the switching transistor in the ON state is supplied to the transmission / reception means.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an electric circuit of a transponder for detecting humidity in a first embodiment of the present invention, FIG. 3 is an external plan view showing a transponder in this embodiment, and FIG. It is sectional drawing of the -A line arrow direction.

In the figure, reference numeral 10 denotes a transponder, which is composed of a transponder main body 30 mounted on the substrate 11 and the substrate 11.
And a humidity detecting section 40 formed in the second section.

The substrate 11 is made of, for example, a polyimide film having a width of 130 mm and a length of 130 mm, and is made of three quarters.
The pair of base electrodes 41 and 42 and the electric resistance layer 43
Is formed. These base electrodes 41 and 42 have a comb shape and are arranged at predetermined intervals so as to mesh with each other. In the present embodiment, the interval between the base electrodes 41 and 42 is set to 5 mm. Further, an electric resistance layer 43 having a thickness of about 20 μm is formed so as to cover these base electrodes 41 and 42. As a result, the peripheral portion where the electric resistance layer 43 is likely to be chipped or peeled is located outside the base electrodes 41 and 42, so that a change in the resistance value between the base electrodes 41 and 42 due to the chipped or peeled electric resistance layer 43 is prevented. It can be extremely reduced, and a stable detection operation over a long period can be obtained.

The electric resistance layer 43 is made of a material containing 20 carbon atoms.
% To 30%, and formed by firing. Here, it is preferable that the thickness of the electric resistance layer 43 is 50 μm or less and 5 μm or more. That is, when the electric resistance layer 43 is formed to have a thickness of 50 μm or more, cracks are liable to be generated, and the divergence of permeated moisture is reduced. If a crack occurs in the electric resistance layer 43, a large change occurs in electric resistance, so that the performance as a humidity sensor decreases. Further, when the divergence of the moisture permeating the electric resistance layer 43 decreases, the speed of following the change in humidity decreases. Further, when the electric resistance layer 43 is formed to a thickness of 5 μm or less, the divergence of moisture becomes extremely high and cracks are unlikely to occur, but the permeability of moisture decreases and the ratio of the change in resistance value to the change in humidity becomes extremely small. It becomes low and does not function as a humidity sensor.

One end of each of the base electrodes 41 and 42 is connected to the transponder main body 30. The transponder main body 30 includes an element main body 31, an antenna line 32, and a storage battery 33.

The element body 31 includes a rectifying / smoothing circuit 51,
It comprises a main circuit 52, a power supply switching circuit 53, and a resistor 54.

The input side of the rectifying / smoothing circuit 51 is connected to the antenna connection terminals 31a and 31b.
2 is rectified and smoothed into a DC current, which is temporarily stored in a capacitor. This voltage V1 is supplied to the main circuit 5 via a power supply switching circuit 53.
2 to each component. Further, the capacity of the capacitor is set to a value capable of storing a sufficient charge for transmitting a response signal.

The main circuit 52 includes a central processing unit 521, a high frequency circuit 522, a memory 523, and an analog / digital (hereinafter, referred to as A / D) conversion circuit 524.

The central processing unit 521 mainly includes a well-known CPU, operates based on a preset program, and reads the voltage of the humidity detecting unit 40 via an A / D conversion circuit 524 when the operation is started. Store value in memory 523
Is converted into binary data together with the information stored in the memory and transmitted as a response signal via the high-frequency circuit 522.

The high-frequency circuit 522 includes a transmission / reception circuit for radio waves of the communication frequency. The transmission / reception circuit is connected to the antenna line 32 via the antenna connection terminals 31a and 31b. After that, the data is output to the central processing unit 521, and the transmission circuit transmits the binary data output from the central processing unit 521 as a response signal.

The memory 523 is composed of a read-only memory (ROM) in which 8-bit identification information unique to each transponder and other predetermined information are stored in advance as information that becomes a part of response information. And outputs the stored information to the central processing unit 521 when a read signal is input from the CPU.

The power supply switching circuit 53 includes two diodes 5
31, 532 and a field effect transistor (hereinafter, FET)
The anode of the diode 531 is connected to the gate of the FET 533 and the output terminal of the rectifying / smoothing circuit 51. The drain of the FET 533 is connected to the power supply terminal 31c, and the source is connected to the anode of the diode 532. The cathodes of the diodes 531 and 532 are connected to a power supply line (not shown) of the main circuit 52, so that power can be supplied to the central processing unit 521, the high-frequency circuit 522, and the memory 523. Further, the cathodes of the diodes 531 and 532 are connected to the terminal 31 e via the resistor 54 and the A / D conversion circuit 5.
24 is connected to one input terminal.

As shown in FIG. 5, the transponder main body 30 includes an element main body 31 and a loop-shaped antenna wire 32.
And a storage battery 33 such as a lithium battery is fixedly arranged on a case base 34, and the storage battery 33 is covered with a case lid 35. The case base 34 and the case lid 35 are formed of a synthetic resin that can pass electromagnetic waves. The antenna line 32 is formed so as to resonate at a predetermined frequency used for transmission and reception (hereinafter, referred to as a communication frequency).

The element body 31 is, as shown in FIG.
A chip 36 and a rectangular parallelepiped resin package 37 surrounding the chip 36 are provided. Antenna connection terminals 31a and 31b are provided on one side of the package 37, and a power supply terminal 31c and a ground terminal 31d are provided on the other side. Terminals 31e and 31f for connecting the unit 40 are provided.

Next, the operation of humidity detection using the transponder 10 having the above-described configuration will be described.

When humidity is detected by the transponder 10, the transponder 10 is installed so that the electric resistance layer 43 of the humidity detecting section 40 is exposed to the atmosphere to be detected.

In the normal state, the transponder 10 is not supplied with power from the rectifying / smoothing circuit 51 and the storage battery 33. When the transponder 10 receives the electromagnetic wave of the inquiry signal, the transponder 10 is stored in the capacitor of the rectifying / smoothing circuit 51 and outputs the voltage V1. Is done. Thus, when the voltage V1 is applied to the gate of the FET 533, the FET 533 switches from the off state to the on state, and the power of the voltage V2 (= V1) is supplied from the storage battery 33 connected to the power supply terminal 31c via the FET 533. 52 are supplied to each component. That is, when receiving the electromagnetic wave of the interrogation signal, the transponder 10 receives the supply of power from the storage battery 33 and transmits a response signal.

On the other hand, since the electric resistance layer 43 of the humidity detecting section 40 is exposed in the atmosphere to be detected, the humidity according to the humidity in the atmosphere permeates the electric resistance layer 43. Therefore, the base electrode 4 corresponding to this humidity
The resistance value of the electric resistance layer 43 between 1 and 42 changes.

When the electromagnetic wave of the interrogation signal is received,
Is turned on, power is supplied from the storage battery 33 to the base electrodes 41 and 42 via the resistor 54, and the voltage generated between the base electrodes 41 and 42 at this time is applied to the input side of the A / D conversion circuit 524. The voltage Vdt generated between the base electrodes 41 and 42 is represented by the following equation (1), where R1 is the fixed resistance value of the resistor 54 and Rdt is the resistance value between the base electrodes 41 and 42. Therefore, the voltage Vdt corresponds to the resistance value Rdt between the base electrodes 41 and 42 on a one-to-one basis.

Vdt = (Rdt · V2) / (R1 + Rdt) (1) As a result, the central processing unit 521 causes the base electrodes 41, 4
The humidity can be detected by the voltage Vdt corresponding to the resistance value between the two, and a response signal including the humidity information is generated.

Also, since the base electrodes 41 and 42 are arranged close to each other in a comb-like shape so as to mesh with each other, the length of the opposing portions of the base electrodes 41 and 42 must be set large within a small area. Can be. Thereby, the detection accuracy in high humidity can be improved. That is, when the length of the facing portion of the base electrodes 41 and 42 is short, unevenness of moisture permeation into the electric resistance layer 43 existing between the base electrodes 41 and 42, unevenness of the thickness of the electric resistance layer 43, and electric resistance. The detection error increases due to the non-uniform distribution state of the carbon molecules in the layer 43 and the like. However, the base electrodes 41, 4
When the length of the opposing portion 2 is set to be large, even if the above-described moist permeation spots and the like occur in the electric resistance layer 43 existing between the base electrodes 41 and 42, the average of the resistance value of each spot portion is obtained. Since the value is detected, the detection error is reduced, and the detection accuracy can be improved. This is, for example, the base electrode 41,
When moisture spots and the like occur in the length direction of the opposing portion of the base electrode 41, the resistance value of each of the portions having different permeation amounts and the like is obtained by combining the resistance values as in the case of connecting the resistors in parallel. , 42.

The distance between the base electrodes 41 and 42 is
Although it depends on the resistance of the electric resistance layer 43, the resistance between the base electrodes 41 and 42 at normal humidity may be set to a high resistance. When the electric resistance layer 43 of the same material and the same thickness is formed, the shorter the distance between the base electrodes 41 and 42, the lower the resistance value between the base electrodes 41 and 42 and the lower the detection accuracy in low humidity. It is preferable to appropriately set the distance between the base electrodes 41 and 42 according to the material and thickness of the electric resistance layer 43, the set resistance value between the base electrodes 41 and 42, and the like.

FIG. 7 shows the characteristics of the humidity and the resistance of the humidity detecting section 40 in this embodiment. In FIG. 7, a straight line A is a straight line indicating the characteristic of the humidity detecting unit 40 in the present embodiment. FIG. 8 shows the characteristics of the humidity and the resistance value of the comparative example. This comparative example is a straight line showing the characteristics of the humidity detecting unit 40 'using the rectangular base electrodes 41' and 42 'as shown in FIG. These two humidity detectors 40, 4
At 0 ', the area of the humidity detecting portion is set to be the same, the components of the electric resistance layer 43, the thickness of the layer, and the distance between the base electrodes are set to be the same. Both are set to 10 kΩ (kilo ohm). Further, in the first embodiment (straight line A), the length of the facing portion of the base electrodes 41 and 42 is set to 30 cm, and in the humidity detector 40 'of the comparative example (straight line B) shown in FIG. 9, the base electrode 41'. , 42 'are 10c in length
m.

As shown in FIGS. 7 and 8, in the first embodiment (straight line A), when the humidity is 30%, 10 kΩ and the humidity 9
It has a characteristic represented by a straight line representing 3 kΩ at 0%, and the rate of change of the resistance value due to humidity change is 70%. On the other hand, in the comparative example (straight line B), when the humidity was 30%, 1
It has a characteristic represented by a straight line indicating 8.5 kΩ at 0 kΩ and 90% humidity, and the rate of change of the resistance value due to a change in humidity is 15%. Therefore, the humidity detecting unit 40 of the first embodiment has a large change in the resistance value with respect to the change in the humidity.
A change in humidity can be minutely detected.

In order to obtain the humidity information from the transponder 10, a transceiver (generally called an interrogator) for transmitting the above-mentioned interrogation signal and receiving the response signal is used to obtain the humidity information from the received response signal. Should be extracted.

As described above, according to the present embodiment, since the humidity detection information can be obtained wirelessly, the installation of the device is very easy and the inside of the rotating body or the like where it is difficult to provide a wire such as a measurement lead is provided. Humidity information at a location such as inside the moving body can be easily obtained.

Since the electric resistance layer 43 has a high electric resistance containing carbon, power consumption during operation of the sensor is small.

Further, since the transponder 10 in the present embodiment receives the supply of power from the storage battery 33 and transmits the response signal only when transmitting the response signal, the consumption of the storage battery 33 can be reduced. Furthermore, the transmission output of the response signal can be increased as compared with the case of driving only by the energy of the received electromagnetic wave without using the storage battery 33, so that the communication distance can be increased. For example, when the communication distance when transmitting the response signal only with the energy of the received electromagnetic wave is about 50 cm and the power is supplied from the storage battery 33, the communication of about 10 times or more of 5 m or more is possible under the same conditions.

Incidentally, the electric resistance layer 43 was formed as described in JP-A-11-261.
The polymer electrolyte composite membrane containing carbon may be formed by blending a water-absorbing polymer with an organic polymer electrolyte as disclosed in Japanese Patent Application Laid-Open Publication No. 6-64. When the water-absorbing polymer is blended in this manner, surrounding moisture easily penetrates into and diffuses into the electric resistance layer 43 due to the water-absorbing polymer, so that the responsiveness of the electric resistance change to the surrounding moisture is enhanced.

Next, a second embodiment of the present invention will be described.

FIG. 10 is a block diagram showing an electric circuit of the transponder 10A for detecting humidity in the second embodiment. In the figure, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. The difference between the second embodiment and the first embodiment is that F
A power supply switching circuit 53A is provided so that the central processing unit 521 can control the on / off of the ET 533. The FET 5 is turned on only when its own identification information is specified in the interrogation signal.
33 is set to the ON state.

That is, the gate of the FET 533 is connected to the control signal output terminal of the central processing unit 521. further,
The central processing unit 521 performs processing as shown in FIG. 11 according to the control program.

When the transponder 10A starts operation after receiving the interrogation signal (S1), the interrogation signal received by the receiving circuit of the high frequency circuit 522 is converted into binary data and transferred to the central processing unit 521. Upon receiving the question signal, the central processing unit 521 decodes the content of the question (S2) and determines whether the question is for itself (S3). The interrogation signal includes the identification information of the transponder to be interrogated. When the identification information matches the identification information assigned to the transponder, it is determined that the interrogator is a question for itself.

If the result of determination in S3 is that the question is not for itself, the process ends. If the question is for itself, the storage battery 33 is connected (S4). That is, the central processing unit 521 outputs the control voltage Vcnt to the power supply switching circuit 53A. Thereby, when the control voltage Vcnt is applied to the gate of the FET 533, the FET 533 switches from the off state to the on state, and the voltage Vcnt from the storage battery 33 connected to the power supply terminal 31c via the FET 533.
2 (= V1) power is supplied to each component of the main circuit 52.

Next, the central processing unit 521 detects the humidity by reading the output data of the A / D converter 524 (S5). Further, the central processing unit 521 converts the information stored in the memory 523 into binary data, generates a response signal from the data and the output data of the A / D converter 524, and converts the response signal into a high-frequency circuit. Transmission is performed via the transmission circuit 522 (S6).

Thereafter, the central processing unit 521 stops outputting the control voltage Vcnt to the power supply switching circuit 53A, and
T533 is turned off to disconnect the storage battery 33 (S
7).

Therefore, the transponder 10A according to the second embodiment operates upon the energy of the received electromagnetic wave output from the rectifying / smoothing circuit 51 when receiving and decoding the interrogation signal, and transmits the response signal. Since only the power is supplied from the storage battery 33 and the response signal is transmitted,
The consumption of the storage battery 33 can be reduced as compared with the first embodiment.

In the above embodiment, the base electrodes 41, 4
Although 2 is comb-shaped, other shapes may be used.
Further, the storage battery 33 may be used to operate only by the output power of the rectification / smoothing circuit 51.

[0066]

As described above, according to the transponder for detecting the humidity according to any one of the first to tenth aspects of the present invention, the humidity information can be wirelessly detected. There is no need to provide any wiring between them, and humidity detection can be performed very easily at a desired location. Furthermore, the humidity detection inside the rotating body or the moving body, for which the wiring is difficult, can be performed very easily.

According to the transponder for detecting humidity according to the second aspect, in addition to the above effects, the electric resistance layer contains carbon, so that it is possible to obtain a small and high resistance value.

According to the humidity detecting transponder of the third aspect, in addition to the above-mentioned effects, the base electrode is formed in a comb-like shape and is arranged close to each other so as to mesh with each other. In this case, the length of the opposed portion of the pair of base electrodes can be set large, so that the detection accuracy at high humidity can be improved.

According to the humidity detecting transponder of the fourth aspect, in addition to the above effects, the resistance value of the electric resistance layer is set to a high resistance value of 1 kΩ or more at the average humidity. The power consumption during the operation of the sensor is reduced, and the rate of change of the electric resistance value due to the penetration of moisture is increased, thereby improving the accuracy of detecting the humidity value.

According to the humidity detecting transponder of the fifth aspect, in addition to the above-described effects, the peripheral portion where the electric resistance layer is likely to be chipped or peeled is located outside the base electrode. Fluctuation in resistance between base electrodes due to chipping or peeling of the layer can be extremely reduced,
A stable detection operation over a long period can be obtained.

According to the humidity detecting transponder of the present invention, in addition to the above-mentioned effects, the surrounding moisture easily penetrates into the electric resistance layer by the water-absorbing polymer and easily diverges. Responsiveness of a change in electric resistance to moisture is enhanced.

Further, according to the humidity detecting transponder of the present invention, in addition to the above effects, the power supply control means controls the power supply while the power supply is being performed from the energy conversion means. During a part of the operation, the power supplied from the power supply connection terminal is supplied to the transmission / reception means by the power supply control means, so that the consumption of the power supply such as a storage battery connected to the power supply connection terminal can be reduced. .

According to the humidity detecting transponder of the present invention, in addition to the above-mentioned effects, the transmitting / receiving means is driven by the power supplied from the energy conversion means when receiving the interrogation signal, and the response signal is transmitted. At times, the transmission / reception means is driven by power supplied from a power supply such as a storage battery, so that power consumption can be reduced.

According to the humidity detecting transponder of the ninth aspect, in addition to the above effects, the induced electromotive force induced in the antenna by the rectifier circuit having a simple configuration can be easily converted to DC power. it can.

Further, according to the humidity detecting transponder of the tenth aspect, in addition to the above-described effects, the on / off state of the switching transistor is directly controlled by the power output from the energy conversion means. It has a very good effect of being very simple.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric circuit of a humidity detecting transponder according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional humidity measurement device.

FIG. 3 is an external plan view showing a transponder according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 is a configuration diagram showing a transponder main body according to the first embodiment of the present invention.

FIG. 6 is a configuration diagram showing an element body according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a humidity / electric resistance value characteristic of the humidity detecting unit according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a humidity / electric resistance value characteristic of a humidity detector of a comparative example in the present invention.

FIG. 9 is a configuration diagram illustrating another humidity detection unit according to the first embodiment of the present invention.

FIG. 10 is a block diagram showing an electric circuit of a transponder according to a second embodiment of the present invention.

FIG. 11 is a flowchart illustrating a processing operation of a transponder according to the second embodiment of the present invention.

[Description of Signs] 10, 10A: transponder, 11: substrate, 30: transponder body, 31: element body, 31a, 31b ...
Antenna connection terminal, 32: antenna wire, 33: storage battery,
34: Case base, 35: Case lid, 36: IC chip, 37: Package, 40: Humidity detector, 41, 4
2, 41 ', 42' ... base electrode, 43 ... electric resistance layer,
51: rectifying / smoothing circuit, 52: main circuit, 53, 53A ...
Power supply switching circuit, 54: resistor, 521: central processing unit, 5
22: high frequency circuit, 523: memory, 524: A / D conversion circuit, 531, 532: diode, 533: FE
T.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01S 13/79 F-term (Reference) 2F073 AA01 AB01 BB01 BC02 CC01 CC11 DD01 DE11 EE12 FF01 FG01 FG02 FG04 GG01 GG04 GG05 GG08 GG09 2G046 AA09 BA01 BA09 BB02 BB04 BC03 EA02 EA04 FA01 5J070 AA03 AD01 AE12 AH31 AK36 AK40 BC13 BC23 BC25 BC28 BC34 BD10

Claims (10)

[Claims] 1. A transponder main body having transmission / reception means for transmitting a response signal when a question signal is received wirelessly, a humidity sensor, and a response signal for generating the response signal including humidity information detected by the humidity sensor. Generating means, wherein the humidity sensor comprises: a substrate made of an insulating plate or film; a pair of base electrodes formed on the substrate; and the substrate so as to connect the pair of base electrodes. An electric resistance layer having a high electric resistance provided on a surface and having a thickness set to 50 μm or less; and an electric signal corresponding to an electric resistance value between the pair of base electrodes as the humidity information to the transponder main body. A transponder for detecting humidity. 2. The transponder for detecting humidity according to claim 1, wherein the electric resistance layer contains carbon. 3. The device according to claim 1, wherein each of the base electrodes is formed in a comb shape, and the comb electrodes are arranged to face each other so as to be close to and mesh with each other. The transponder for detecting humidity described in 1. 4. The electric resistance value of the electric resistance layer between the pair of base electrodes is set to a value of 1 k ohm or more at an average humidity. The transponder for detecting humidity described in 1. 5. The transponder for detecting humidity according to claim 1, wherein the electric resistance layer is formed on the substrate so as to cover the pair of base electrodes. 6. The polymer electrolyte composite membrane containing carbon formed by blending a water-absorbing polymer with an organic polymer electrolyte, wherein the electric resistance layer is formed. A transponder for detecting humidity according to the present invention. 7. The transmitting and receiving means transmits and receives the interrogation signal and the response signal by electromagnetic waves, and converts induced electromotive force induced in an antenna of the transmitting and receiving means by the interrogation signal into power for driving the transmitting and receiving means. Energy conversion means for supplying to the transmission / reception means; a power supply connection terminal for connecting a power supply such as a storage battery; and power supplied from the power supply connection terminal based on power supply from the energy conversion means to the transmission / reception means. The transponder for humidity detection according to any one of claims 1 to 6, further comprising power supply control means for supplying the power. 8. The humidity detecting transponder according to claim 7, wherein the power supply control means supplies the power supplied from the power supply connection terminal to the transmission / reception means only when the response signal is transmitted. 9. The transponder for detecting humidity according to claim 7, wherein said energy conversion means comprises a rectifier circuit. 10. The humidity detecting transponder according to claim 7, wherein said power supply control means includes a switching transistor which is turned on based on power supply from said energy conversion means.