KR102211922B1 - Temperature sensor and Temperature measuring device using surface acoustic wave, Real time Passive temperature measurement system thereof - Google Patents

Abstract

The present invention relates to a temperature measurement system for wirelessly measuring temperature using surface acoustic waves, and in particular, a device with improved accuracy and sensitivity of temperature measurement and easy installation and attachment of a temperature measurement sensor using surface acoustic waves. Is to provide.
Specifically, the present invention has the effect of providing a temperature measurement system using surface acoustic waves that are easy to install or attach to a device to be measured. In addition, the present invention has an effect of providing a temperature measurement system using a surface acoustic wave in which a surface acoustic wave temperature sensor is directly connected to an equipment to be measured, which is an object of temperature measurement, and improves real-time and accuracy of temperature measurement. In addition, the present invention has an effect of providing a temperature measurement system using a surface acoustic wave having a small volume and reduced weight by using a flat planar antenna for a surface acoustic wave temperature sensor. In addition, the present invention has the effect of providing a temperature measurement system using surface acoustic waves capable of reducing manufacturing cost by using a reader having a simple configuration and easy temperature measurement due to high sensitivity.

Description

Temperature sensor and temperature measuring device using surface acoustic wave, and real time passive temperature measurement system using the same.

The present invention relates to a real-time passive temperature measurement system that measures temperature wirelessly using surface acoustic waves, and specifically, it is easy to install and attach a temperature measurement sensor using surface acoustic waves, and improve accuracy and sensitivity of temperature measurement. Is to provide the device.

Since electronic devices such as power switch boards may be damaged by heat, various types of temperature sensors are used as means for measuring and monitoring temperature. Surface Acoustic Wave (SAW) temperature sensor using the temperature characteristics of piezoelectric board and surface acoustic wave is used in electronic devices for miniaturization because it does not require a separate power source and can measure temperature wirelessly.

A system using a SAW temperature sensor according to the prior art will be described based on FIG. 1. The SAW temperature sensor 100 includes a sensor unit 110 and a reader unit 120. The sensor unit 110 includes a piezoelectric plate 111, a transducer 112, a reflector 113, and an antenna 114. The piezoelectric substrate 111 not only expands or contracts the delay line 115 depending on the surrounding temperature, but also affects the physical properties of the piezoelectric substrate, so that the propagation time of the surface acoustic wave changes or the resonance frequency changes. By detecting the change, the temperature can be measured. The transducer 112 may be formed as a comb electrode, and generates a surface acoustic wave by a signal received from an antenna. The reflector 113 serves to propagate the surface acoustic wave generated by the transducer 112 back to the transducer 112 by reflecting the surface acoustic wave at the end of the delay line after passing through the delay line. When the sensor driving signal is transmitted from the reader unit 120 through the antenna, the sensor driving signal is input to the transducer 112 of the sensor unit 110. The piezoelectric plate 111 vibrates by the high-frequency signal input to the transducer 112, and accordingly, a surface acoustic wave propagating along the surface of the piezoelectric plate 111 is generated to propagate the delay line 115 and thereby the reflector 113 ). The surface acoustic wave propagated in this way is reflected by the reflector 113 and transmitted again by the antenna of the sensor unit 110 through the delay line 115 and the transducer 112, and the signal is received by the reader 120. The signal received through the reader 120 can calculate the temperature of the equipment to be measured by analyzing frequency characteristics such as the amplitude or frequency of the frequency.

However, the prior art as described above has the following problems.

That is, since the surface acoustic wave temperature sensor is installed and used in a manner such as attaching a band or spring, there is a problem that the band or spring exposed to a high temperature environment over a long period of time is aging, which makes it brittle and weakens elasticity.

In addition, in the prior art, since the surface acoustic wave temperature sensor is not closely connected to the equipment to be measured, the temperature of the equipment to be measured is transmitted indirectly through a continuous transmission structure such as air or metal. There is a problem of poor performance and accuracy.

In addition, the prior art has a problem in that the height of the temperature sensor element is high and the volume is large by using a single stage antenna (whip antenna) or a spiral antenna for the surface acoustic wave temperature sensor.

In addition, in the prior art, since measurement is possible only when the distance between the sensor unit and the reader is located within 3 meters, the measurement distance is low, so it is inconvenient to use when measuring the temperature of the equipment to be measured, and the configuration of the reader is complicated.

Republic of Korea Patent Publication No. 2004-57477 discloses a sensor system for detecting temperature changes using surface acoustic waves.

The present invention has been conceived to solve the conventional problems as described above, and the present invention is to provide a real-time passive temperature measurement system using surface acoustic waves that are easy to install or attach to a device to be measured.

In addition, the present invention provides a real-time passive temperature measurement system using a surface acoustic wave with improved real-time and accuracy of temperature measurement by directly connecting a surface acoustic wave temperature sensor to a device to be measured.

In addition, the present invention provides a real-time passive temperature measurement system using a surface acoustic wave having a small volume and reduced weight by using a flat planar antenna for a surface acoustic wave temperature sensor.

In addition, the present invention is to provide a real-time passive temperature measurement system using a surface acoustic wave, which is easy to measure the temperature of a device to be measured because it is possible to measure temperature even when the distance between the sensor unit and the reader is 3 meters or more.

According to a feature of the present invention for achieving the object as described above, the present invention is an insulating support provided in the lower substrate receiving groove; A piezoelectric plate coupled to the substrate receiving groove under the insulating support; A surface acoustic wave generator coupled to a lower portion of the piezoelectric plate so as to protrude from the insulating support portion; A planar antenna part provided on the insulating support part; And a cover part provided on the top of the planar antenna part, and a SAW temperature sensor using a surface acoustic wave. The piezoelectric plate and the planar antenna unit may be connected by a metal arm. In addition, it may be characterized in that they are connected to the feed point and the ground point of the flat antenna unit formed at positions corresponding to the signal interface and the ground interface of the piezoelectric board by metal arms, respectively. The planar antenna unit may be provided in the form of an attachment piece and may be coupled to the insulating support unit. In addition, the planar antenna unit may be configured to be diffracted on a plane. The insulating support portion and the cover portion may further include a fixing hole through which a screw for fixing is passed. Here, the thickness of the insulating support may be configured to be 12mm to 40mm. The surface acoustic wave generator may include a piezoelectric plate, a transducer, and a reflector, and may be configured to generate different surface acoustic waves according to the temperature of the device under measurement.

Alternatively, the present invention includes an energy storage unit that stores a driving signal received from a reader and outputs a driving signal whose power is increased by the stored load to the SAW temperature sensor unit; And a SAW temperature sensor that generates a surface acoustic wave according to a driving signal of the energy storage unit. The energy storage unit may include a charge pump converting the received RF signal into a DC signal; A DC-DC booster that increases the voltage of the converted DC signal; And a capacitor that stores energy of the increased voltage. The SAW temperature sensor unit may include a piezoelectric plate, a transducer, and a reflective unit to generate different surface acoustic waves according to the temperature of the device to be measured.

Alternatively, the present invention provides a temperature measuring device configured to detect a temperature value by generating different surface acoustic waves according to the temperature of the device to be measured; and an outgoing channel for transmitting a driving signal for generating a surface acoustic wave from the temperature measuring device, and the generated surface acoustic waves. A SAW temperature measurement system comprising: a reader configured to include a receiving channel for receiving a signal of, wherein the temperature measuring device stores a driving signal received from the reader and transmits a driving signal with increased power to the stored load. An energy storage unit outputting to the SAW temperature sensor unit; And a SAW temperature sensor unit that generates a surface acoustic wave according to a driving signal of the energy storage unit. The energy storage unit may include a charge pump converting the received RF signal into a DC signal; A DC-DC booster that increases the voltage of the converted DC signal; And a capacitor for storing energy of the increased voltage. The SAW temperature sensor unit may include a piezoelectric plate, a transducer, and a reflective unit to generate different surface acoustic waves according to the temperature of the device to be measured.

In the real-time passive temperature measurement system using surface acoustic waves according to the present invention as seen above, the following effects can be expected.

That is, in the present invention, there is an effect of providing a real-time passive temperature measurement system using surface acoustic waves that are easy to install or attach to an equipment to be measured.

In addition, in the present invention, there is an effect of providing a real-time passive temperature measurement system using a surface acoustic wave with improved real-time and accuracy of temperature measurement by directly connecting a surface acoustic wave temperature sensor to a facility to be measured.

In addition, in the present invention, there is an effect of providing a real-time passive temperature measurement system using a surface acoustic wave having a small volume and reduced weight by using a flat planar antenna for a surface acoustic wave temperature sensor.

In addition, in the present invention, it is possible to measure temperature even when the distance between the sensor unit and the reader is 3 meters or more, so it is easy to measure the temperature of the equipment to be measured, and a real-time passive using surface acoustic waves that can reduce the manufacturing cost by using a simple reader. There is an effect of providing a temperature measurement system.

1 shows a system using a SAW temperature sensor according to the prior art.
2 is a block diagram showing the configuration of a real-time passive temperature measurement system using surface acoustic waves according to an embodiment of the present invention.
3 is a side cross-sectional view showing the configuration of a SAW temperature sensor unit according to an embodiment of the present invention.
4 shows a configuration of a surface acoustic wave generator according to an embodiment of the present invention.
5 shows a shape of an antenna unit according to an embodiment of the present invention.
6 shows a form in which the SAW temperature sensor according to an embodiment of the present invention is fixed to a measurement object.
7 shows a form in which the SAW temperature sensor according to an embodiment of the present invention is fixed to another object to be measured.

Hereinafter, a real-time passive temperature measurement system using surface acoustic waves according to the present invention as described above will be described in detail with reference to the accompanying drawings.

FIG. 2 shows a real-time passive temperature measurement system (1, hereinafter referred to as “SAW temperature measurement system”) using surface acoustic waves according to an embodiment of the present invention.

The SAW temperature measuring system 1 includes a temperature measuring device 10 and a reader 20, and although not shown in the drawing, it may further include a configuration such as a signal processing unit and a display unit. Hereinafter, the configuration of the temperature measuring device 10 and the reader 20, which are characteristics of the present invention, will be described in detail.

The temperature measuring device 10 may be configured to include an energy storage unit 11 and a SAW temperature sensor unit 12, and the reader 20 includes a transmission channel 21 and a reception channel 22.

The energy storage unit 11 increases the power of the signal received from the transmission channel 21 of the reader so that the driving signal can be detected even when the distance between the temperature measuring device 10 and the reader 20 is 3 meters or more away. Configuration. To this end, the energy storage unit 11 may include a charging pump 11a, a DC-DC booster 11b, and a capacitor 11c. The charge pump 11a can use a Dickson charge pump and converts the received RF signal into DC conversion using this. For example, when a 915MHz signal of 20dBm is transmitted from the transmitter channel 21 of the reader 20, the power converted to DC from the charge pump 11a is 0.5V to 1.0V, and the transducer of the temperature measuring instrument 10 It corresponds to low power to generate an acoustic wave. The DC-DC booster 11b increases a voltage of 0.5V to 1.0V corresponding to low power to 1.8V. The capacitor 11c stores energy of an increased voltage and transmits a driving signal to the SAW temperature sensor unit 12 with a load in which electrical energy is stored. The sensitivity of the energy storage unit 11 is -10 dBm or less, and when the transmission signal strength (ERIP) is 20 dBm (915 MHz), the signal detection distance between the energy storage unit 11 and the SAW temperature sensor unit 12 is 10 meters or more. do. When the transmission signal power is increased, since the signal sensing distance between the energy storage unit 11 and the SAW temperature sensor unit 12 increases, the sensitivity is increased compared to the conventional temperature sensor using surface acoustic waves. In the above embodiment, a 3.3uF capacitor was used. However, if the working time is increased by increasing the capacity of the capacitor, the signal transfer time of the surface acoustic wave generated by the temperature measuring instrument 10 is extended to 500us or more, thereby simplifying the signal reception method and making the FFT conversion You don't need it. Therefore, since it is possible to accurately read the received signal while counting the received signal by using a simple controller (MCU), the complexity and cost of the reader 20 can be significantly reduced.

The energy storage unit 11 as described above is to enable the temperature measurement of the equipment to be measured even when the distance between the temperature measuring device 10 and the reader 20 is 3 meters or more, and a distance of 3 meters or more is required. If not, the energy storage unit 11 may be configured not to operate, or a temperature measuring device may be configured using the SAW temperature sensor unit 12 excluding the energy storage unit 11.

Next, FIG. 3 shows a specific embodiment of the SAW temperature sensor unit 12. According to an embodiment, the SAW temperature sensor unit 12 of the present invention includes a surface acoustic wave generating unit 31, an IC substrate 32, an insulating support unit 33, an antenna unit 34, and a cover unit 36. do.

The surface acoustic wave generator 31 is configured to generate a surface acoustic wave according to a driving signal, and may include a piezoelectric plate 311, a transducer 312, and a reflective unit 313 as shown in FIG. 4.

The piezoelectric substrate 311 not only expands or contracts the delay line 115 depending on the surrounding temperature, but also affects the physical properties of the piezoelectric substrate, so that the propagation time of the surface acoustic wave changes or the resonance frequency changes.

In the transducer 312, an inter-digital transducer (IDT) may be used as a comb electrode, and a surface acoustic wave is generated by the received driving signal.

The reflector 313 serves to propagate the surface acoustic wave generated by the IDT 312 through the delay line and reflect the surface acoustic wave at the end of the delay line and propagate back to the IDT 312.

Returning to FIG. 3 again, the IC substrate 32 of FIG. 3 includes a signal interface and a ground interface in a configuration in which the surface acoustic wave generator 31 protrudes from the bottom.

The insulating support 33 is formed of an insulating material in a configuration that fixes the IC substrate 32 and includes a substrate receiving groove 33a for accommodating the IC substrate so that the IC substrate is not exposed to the outside. This configuration is intended to prevent exposure of the contact points or bonding pads of the IC substrate 32. The thickness of the insulating support 33 is selected according to the performance of the antenna, and it is preferable that the thickness is thick because it affects the radiation field of the antenna. In particular, in order to stably operate the antenna in the required frequency band range, it is preferable that the thickness of the insulating support 33 is configured to be 12mm to 40mm.

In addition, the insulating support 33 may further include a fixing hole 33b. The fixing hole 33b has a shape of a through hole, and is configured such that a screw or the like passes through the insulating support 33 through the fixing hole 33b, so that the temperature can be easily fixed to the equipment to be measured. Such a fixing method has no problem of being broken or weakened even when exposed to high temperature for a long period of time compared to a conventional belt or spring attachment method, and has an effect of stably mounting.

The antenna unit 34 is composed of a flat flat antenna in the form of an attachment piece on the insulating support unit 33. By configuring the antenna in a flat plane shape, a device having a lower height and smaller volume than a configuration using a single-stage antenna (whip antenna) or a spiral antenna can be configured. In addition, the flat flat antenna unit has the advantage of high reliability and high durability because it is not destroyed and has strong electrostatic resistance because the ground line and the feed line themselves are in communication.

The specific shape of the antenna unit 34 will be described with reference to FIG. 5. FIG. 5 shows an antenna part 34 formed as an attachment piece on the insulating support part 33 of FIG. 3 viewed from above. It is configured to increase the reception sensitivity by configuring the shape of the antenna unit 33 in a diffractive manner. Although the illustrated embodiment is configured in the form of an inverted English capital letter'G', it may be configured in the form of an English capital letter'S', and various types of modifications are possible within a range configured as a diffraction formula.

The antenna unit 34 includes a feed point and a ground point, and the feed point and the ground point are respectively connected to the signal interface and the ground interface of the IC board 32 and the metal arm 35. That is, the feed point and the ground point of the antenna unit 34 are formed at positions coincident with the signal interface and the ground interface of the IC substrate 32. The metal arm 35 may be formed of a material such as silver, beryllium bronze, stainless steel, or FPC. The antenna unit 34 and the IC substrate 32 are configured to be electrically connected through the metal arm 35 to enhance the performance of the antenna.

Returning to FIG. 3 again, the cover part 36 of FIG. 3 is provided on the top of the antenna part 34 and serves to protect the antenna part 34 and is made of an insulating material. A through hole-shaped fixing hole 36b corresponding to the fixing hole 33b of the insulating support part 33 may also be formed in the cover part 36. The fixing hole 36b of the cover part 36 also corresponds to a configuration in which a screw or the like passes through and can be easily fixed to the equipment to be measured.

In particular, the surface acoustic wave generator 31 is mounted in a protruding form on the lower surface of the insulating support part 33 in which the IC substrate 32 is accommodated, and is configured to directly contact the equipment to be measured to measure the temperature. Therefore, the temperature of the equipment to be measured is not transmitted indirectly through the heat transfer structure, and the surface acoustic wave generator 31 can directly detect the temperature of the equipment to be measured, thereby improving the real-time and accuracy of temperature measurement. .

Hereinafter, a mechanism of operation of a real-time passive temperature measurement system using surface acoustic waves as described above will be described.

The SAW temperature sensor unit 12 of the temperature measuring device 10 is attached to and installed in the equipment to be measured to measure the temperature. At this time, the surface acoustic wave generator 31 protruding from the bottom of the SAW temperature sensor unit 12 is attached so that it can be directly contacted with the equipment to be measured, and screwed through the fixing holes 33b and 36b to be avoided. Fix it to the measuring equipment.

When a driving signal for temperature measurement is transmitted from the reader 20 through an antenna, the temperature measuring device 11 receives the driving signal. At this time, even when the distance between the temperature measuring device 10 and the reader 20 is 3 meters or more, the energy storage unit 11 operates to detect the driving signal. The energy storage unit 11 converts the signal received through the charge pump 11a into DC and increases the voltage through the DC-DC booster 11b. In addition, the energy storage unit 11 stores energy of an increased voltage in the capacitor 11c and transmits a driving signal to the SAW temperature sensor unit 12 with a load in which electrical energy is stored.

The driving signal is input to the transducer 312 of the SAW temperature sensor unit 12, and a surface acoustic wave propagating along the surface of the piezoelectric substrate 311 is generated, propagating along the delay line, and propagating to the reflecting unit 313. The propagated surface acoustic wave is reflected by the reflecting unit 313 and transmitted again by the antenna through the delay line and the transducer.

The reader 20 may calculate the temperature of the equipment to be measured by receiving a signal and analyzing a frequency characteristic such as an amplitude or a frequency of a frequency. At this time, in the case of detecting the temperature at a plurality of points using the plurality of SAW temperature sensor units 12, the surface acoustic waves formed by each temperature sensor unit 12 are configured to use different center frequencies, It can also be configured to monitor the temperature of the point.

Meanwhile, the SAW temperature sensor according to the present invention may be stably fixed to the object to be measured by having a case.

In this case, the case can be various embodiments according to the shape of the object to be measured, and a representative example will be described below with reference to the drawings.

6 illustrates a form in which the SAW temperature sensor according to an embodiment of the present invention is fixed to a measurement object.

As shown here, when the measurement object P1 has a cylindrical shape, the case 40 includes an outer casing 42 and a curved bottom portion 44.

The outer casing 42 is in the form of a box with an open bottom, and SAW temperature sensor components such as an insulation support, a piezoelectric plate, a surface acoustic wave generator, a flat antenna and a cover, as described above, are mounted inside.

In addition, a curved bottom portion 44 having a curved bottom surface is coupled to the bottom of the outer casing 42 so that the upper portion shields the lower portion of the outer casing 42 and the bottom surface is in close contact with the cylindrical measurement object P1.

At this time, the case 40 and the measurement object P1 may be coupled by screw fixing, or may be attached by an adhesive material.

7 illustrates a form in which the SAW temperature sensor according to an embodiment of the present invention is fixed to another object to be measured.

As shown, when the fixing protrusion P22 is formed on the measurement object P2 and the case 40 is fixed on the fixing protrusion P22, the case 40 is an outer casing 42 And a protruding bottom portion 46.

The outer casing 42 has a box shape with an open bottom, and the SAW temperature sensor component as described above is mounted inside.

And the bottom of the outer casing 42 is coupled to a protrusion bottom part 46 that extends to one side and can be fastened to the fixing protrusion P22.

In addition, the protrusion of the protrusion bottom part 46 is coupled and fixed to the fixing protrusion P22.

At this time, the case 40 and the measurement object P2 may be fixed by pressing the protrusion of the protrusion bottom part 46 into the fixing protrusion P22, or additional screw fixing may be included for stable fixing.

The rights of the present invention are not limited to the embodiments described above, but are defined by what is described in the claims, and that a person having ordinary knowledge in the field of the present invention can make various modifications and adaptations within the scope of the rights described in the claims. It is self-evident.

The present invention relates to a temperature measurement system for wirelessly measuring temperature using surface acoustic waves, and according to the present invention, there is an advantage of providing a temperature measurement system with improved accuracy and sensitivity of temperature measurement and easy installation.

10: temperature measuring device 11: energy storage unit
12: SAW temperature sensor unit 20: reader
21: sending channel 22: receiving channel
31: surface acoustic wave generator 32: IC substrate
33: insulation support portion 34: antenna portion
35: metal arm 36: cover
110: sensor unit 111, 311: piezoelectric board
112, 312: transducer 113: reflector
114: antenna 120: reader unit
313: reflector

Claims (9)

An energy storage unit that stores a driving signal received from the reader and outputs a driving signal whose power is increased by the stored load to the SAW temperature sensor unit;
A SAW temperature sensor unit that generates a surface acoustic wave according to a driving signal of the energy storage unit;
An outer casing accommodating the energy storage unit and the SAW temperature sensor unit; And
It comprises a bottom portion shielding the opening of the outer casing:
The outer surface of the bottom portion is formed in a curved surface:
The SAW temperature sensor unit,
Insulation support having a substrate receiving groove at the bottom;
A piezoelectric plate coupled to the substrate receiving groove under the insulating support;
A surface acoustic wave generator coupled to a lower portion of the piezoelectric plate so as to protrude from the insulating support portion;
A planar antenna part provided on the insulating support part; And
Temperature measuring device using a surface acoustic wave, characterized in that configured to include a cover provided on the upper portion of the flat antenna unit.
The method of claim 1,
Temperature measuring device using surface acoustic waves, characterized in that the piezoelectric plate and the planar antenna unit are connected by a metal arm.
The method of claim 2,
The signal interface and the ground interface of the piezoelectric board,
A temperature measuring device using a surface acoustic wave, which is formed at a position corresponding to the feed point and the ground point of the flat antenna unit, and is connected to the feed point and the ground point of the flat antenna unit by metal arms, respectively.
The method of claim 1,
A temperature measuring device using a surface acoustic wave, characterized in that the flat antenna unit is provided in the form of an attachment piece and coupled to the insulating support unit.
The method of claim 1,
A temperature measuring device using surface acoustic waves, characterized in that the planar antenna unit is configured to be diffracted on a plane.
The method of claim 1,
The temperature measuring device using a surface acoustic wave, characterized in that the insulating support portion and the cover portion further comprises a fixing hole through which a screw for fixing passes.
The method of claim 1,
Temperature measuring device using surface acoustic waves, characterized in that the thickness of the insulating support is 12mm to 40mm.
The method of claim 1,
A temperature measuring device using surface acoustic waves, characterized in that the surface acoustic wave generator generates different surface acoustic waves according to the temperature of the device to be measured, including a piezoelectric plate, a transducer, and a reflector.
The method of claim 1, wherein the energy storage unit,
A charge pump converting the received RF signal into a DC signal;
A DC-DC booster that increases the voltage of the converted DC signal; And
A temperature measuring device using a surface acoustic wave, characterized in that it comprises a capacitor that stores the energy of the increased voltage.

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