Ultrasonic atomizer oscillation unit, ultrasonic atomizer

Abstract

To provide an ultrasonic atomizer oscillation unit that can reliably prevent both the failure of the atomizing transducer and the failure of the oscillation board. [Solution] This ultrasonic atomizer oscillation unit 20 comprises an atomizing transducer 21 and an oscillation board 40. The atomizing transducer 21 has an irradiation surface that is positioned in contact with the atomizing liquid. The oscillation board 40 has an oscillation circuit 43 that generates a high-frequency alternating current for transducer oscillation from a direct current and outputs it to the atomizing transducer 21, and a control unit 50 that controls the operation of the oscillation circuit 43. The control unit 50 monitors a first DC signal obtained by stepping down and rectifying the alternating current generated by the oscillation circuit 43, and a second DC signal obtained by a temperature sensor 31 installed on the atomizing transducer 21. The control unit 50 then controls the operation of the oscillation circuit 43 to stop based on a change in at least one of the first DC signal and the second DC signal.

Description

Technical Field

[0001] The present invention relates to an oscillation unit for an ultrasonic nebulizer and an ultrasonic nebulizer.

Background Art

[0002] Conventionally, an ultrasonic nebulizer that atomizes a liquid for atomization in a treatment tank by ultrasonic waves is well known (for example, see Patent Document 1). The ultrasonic nebulizer described in Patent Document 1 has a structure in which an atomization vibrator is installed at the bottom of a treatment tank storing the liquid for atomization. When ultrasonic waves generated by the atomization vibrator are irradiated onto the liquid for atomization, the liquid for atomization is atomized and dispersed into the space.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in this type of ultrasonic nebulizer, if the atomization vibrator is accidentally operated (dry-run operation) without the liquid for atomization, the risk of the atomization vibrator failing due to excessive heat generation increases. Also, even if it is not in a dry-run state, if the atomization vibrator continues to operate with bubbles or the like adhering to the irradiation surface, the risk of the atomization vibrator failing due to excessive heat generation still increases.

[0005] Furthermore, when using an ultrasonic atomizer oscillation unit comprising an oscillation board and an atomizing transducer, the task of connecting or disconnecting the oscillation board and the atomizing transducer is basically left to the user. Consequently, users may accidentally operate the ultrasonic atomizer with the transducer disconnected, which could lead to a malfunction of the oscillation board. However, to date, no device has been proposed that can reliably prevent both the failure of the atomizing transducer and the failure of the oscillation board.

[0006] The present invention has been made in view of the above problems, and its objective is to provide an ultrasonic atomizer oscillation unit and an ultrasonic atomizer that can reliably prevent both failure of the atomizing transducer and failure of the oscillation board. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is an ultrasonic atomizer oscillation unit comprising: an atomizing vibrator having an irradiation surface arranged in contact with a liquid to be atomized; an oscillation circuit that generates a high-frequency alternating current for vibrator oscillation from a direct current and outputs it to the atomizing vibrator; and an oscillation board having a control unit that controls the operation of the oscillation circuit, wherein the control unit monitors a first direct current signal obtained by stepping down and rectifying the alternating current generated by the oscillation circuit and a second direct current signal obtained by a temperature sensor installed on the atomizing vibrator, and controls the operation of the oscillation circuit to stop it based on a change in at least one of the first direct current signal and the second direct current signal.

[0008] Accordingly, according to the invention described in claim 1, the control unit simultaneously monitors a first DC signal obtained by stepping down and rectifying the AC generated by the oscillation circuit, and a second DC signal obtained by the temperature sensor. In other words, the control unit not only directly monitors the voltage change of the AC generated by the oscillation circuit, but also directly monitors the temperature change of the atomizing vibrator at the same time. The control unit then performs control to stop the operation of the oscillation circuit before a failure occurs, based on the change in at least one of the two monitored targets, the first DC signal and the second DC signal. Therefore, unlike the case where the operation is stopped based on the change in only one monitored target, it is possible to reliably prevent both the failure of the atomizing vibrator and the failure of the oscillation board.

[0009] The invention described in claim 2 is characterized in that, in claim 1, control is performed to stop the operation of the oscillation circuit based on which of the following occurs first: a change of a predetermined value or more in the first DC signal and a change of a predetermined value or more in the second DC signal.

[0010] Therefore, according to the invention described in claim 2, the operation of the oscillation circuit can be quickly stopped based on the previously occurring change. Thus, the occurrence of a malfunction can be prevented more reliably.

[0011] The invention described in claim 3 is characterized in that, in claim 2, the control unit is a central processing unit, and the oscillator board has a resistive voltage divider circuit that divides the AC generated by the oscillator circuit with resistors to reduce the voltage to a value lower than the drive voltage of the central processing unit, and a rectifier circuit that rectifies the AC reduced by the resistive voltage divider circuit and outputs the first DC signal.

[0012] Therefore, according to the invention described in claim 3, a first DC signal is obtained that increases or decreases in direct conjunction with the change in AC generated by the oscillation circuit, making it possible to accurately and quickly detect abnormalities in the oscillation circuit. Furthermore, since the voltage value of the obtained first DC signal is set lower than the drive voltage of the central processing unit, it can be taken into the central processing unit as an input signal and monitored. It is preferable that the resistive voltage divider circuit steps down the voltage value of the rectified first DC signal to 90% or less of the drive voltage of the central processing unit, more preferably to 85% or less, and even more preferably to 70% or more and 80% or less.

[0013] The invention described in claim 4 is characterized in that, in claim 3, the central processing unit, which is the control unit, monitors the voltage value of the first DC signal output by the rectifier circuit, continues the operation of the oscillation circuit when the voltage value is less than or equal to a first threshold, and stops the operation of the oscillation circuit when the voltage value exceeds the first threshold.

[0014] Therefore, according to the invention described in claim 4, the central processing unit stops the operation of the oscillation circuit when the voltage value of the first DC signal exceeds the first threshold, thereby stopping the AC output from the oscillation circuit to the atomizing vibrator, and stopping the atomizing vibrator. As a result, failure of the atomizing vibrator caused by the input of a high-voltage AC can be prevented proactively and reliably.

[0015] The invention described in claim 5 is characterized in that, in claim 2, the control unit is a central processing unit, the atomizing vibrator is a flat ceramic piezoelectric body having a non-irradiated surface on the opposite side of the irradiated surface, the temperature sensor is a thermistor element mounted on the non-irradiated surface to detect the vibrator temperature when energized, and outputs the second DC signal with a voltage value lower than the drive voltage of the central processing unit.

[0016] Therefore, according to the invention described in claim 5, a second DC signal is obtained by the thermistor element, which is a temperature sensor, that increases or decreases in direct conjunction with the change in temperature of the atomizing transducer, so that excessive heat generation of the atomizing transducer can be detected accurately and quickly. Furthermore, since the voltage value of the obtained second DC signal is lower than the drive voltage of the central processing unit, it can be taken into the central processing unit as an input signal and monitored. In addition, since the temperature sensor is mounted on a non-irradiated surface, the temperature sensor does not come into contact with the atomizing liquid, making wiring easier, and there is no risk of adversely affecting the ultrasonic waves emitted from the irradiation surface. The voltage value of the second DC signal output by the thermistor element, which is a temperature sensor, is preferably 90% or less, more preferably 85% or less, and even more preferably 70% to 80% of the drive voltage of the central processing unit.

[0017] The invention described in claim 6 is characterized in that, in claim 5, the central processing unit, which is the control unit, monitors the voltage value of the second DC signal output by the thermistor element, continues the operation of the oscillation circuit when the voltage value is less than or equal to the second threshold, and stops the operation of the oscillation circuit when the voltage value exceeds the second threshold.

[0018] Accordingly, according to the invention described in claim 6, the central processing unit stops the operation of the oscillation circuit when the voltage value of the second DC signal output by the thermistor element exceeds the second threshold value, thereby stopping the AC output from the oscillation circuit to the atomizing vibrator, and stopping the atomizing vibrator. As a result, failure of the atomizing vibrator due to excessive heat generation can be prevented in advance and reliably.

[0019] The invention described in claim 7 is essentially an ultrasonic atomizer equipped with an ultrasonic atomizer oscillation unit as described in any one of claims 1 to 6. [Effects of the Invention]

[0020] As described in detail above, according to the invention recited in claims 1 to 7, it is possible to surely prevent both the failure of the atomizing vibrator and the failure of the oscillation substrate.

Brief Description of the Drawings

[0021] [Figure 1] Schematic configuration diagram showing the ultrasonic atomizer in the present embodiment. [Figure 2] Plan view showing the non-irradiation surface side of the atomizing vibrator. [Figure 3] Cross-sectional view showing the atomizing vibrator. [Figure 4] Block diagram showing the electrical configuration of the oscillation unit for the ultrasonic atomizer. [Figure 5] Table showing the results of the required time until stop during the dry-running operation in the verification test performed on the atomizing vibrator and the oscillation substrate.

Mode for Carrying Out the Invention

[0022] Hereinafter, an embodiment in which the present invention is embodied in an ultrasonic atomizer will be described in detail based on FIGS. 1 to 5.

[0023] As shown in FIG. 1, the ultrasonic atomizer 10 includes a treatment tank 11 for storing the atomizing liquid A1 (tap water in this embodiment). The ultrasonic atomizer 10 in this embodiment is a device that atomizes the atomizing liquid A1 by irradiating the atomizing liquid A1 in the treatment tank 11 with ultrasonic waves S1. The treatment tank 11 has a bottom 12 and a pair of side walls 13 and 14 facing each other, and is formed in a substantially rectangular parallelepiped shape using a resin material such as ABS resin (acrylonitrile butadiene styrene resin).

[0024] Further, the ultrasonic atomizer 10 includes an oscillation unit 20 for the ultrasonic atomizer, and the oscillation unit 20 for the ultrasonic atomizer includes an atomizing vibrator 21. More specifically, a recess 16 that opens in the internal space of the treatment tank 11 is formed at the center of the bottom 12 of the treatment tank 11. And the atomizing vibrator 21 is attached via a packing 17 within the formation region of the recess 16.

[0025] As shown in Figures 1 to 3, the atomizing transducer 21 is a disc-shaped (flat) ceramic piezoelectric body having an irradiated surface 22 positioned in contact with the atomizing liquid A1, and a non-irradiated surface 23 located on the opposite side of the irradiated surface 22. Irradiated surface-side terminals 24 are formed on the entire irradiated surface 22 of the atomizing transducer 21. Non-irradiated surface-side terminals 25 are formed in a circular shape in the center of the non-irradiated surface 23 of the atomizing transducer 21. Part of the non-irradiated surface-side terminals 25 are formed to wrap around to the side of the transducer and the outer circumference of the non-irradiated surface 23. One end of the wiring 32 is connected to the non-irradiated surface-side terminals 25 and the irradiated surface-side terminals 24, and the other end is connected to the oscillation substrate 40.

[0026] Furthermore, a pair of sensor terminals 27 are formed in an insulating region 26 located between the illumination-side terminal 24 and the non-illumination-side terminal 25 on the non-illumination surface 23. One end of the wiring 33 is connected to each of the sensor terminals 27, and the other end is connected to the oscillation board 40. Thermistor elements 31 (temperature sensors) are surface-mounted on both sensor terminals 27 and are mounted on the non-illumination surface 23 to detect the oscillator temperature when energized. In other words, the thermistor elements 31 are mounted on the non-illumination surface 23, avoiding the formation positions of the illumination-side terminal 24 and the non-illumination-side terminal 25, which are terminals for driving the atomizing oscillator 21. The thermistor elements 31 are mounted somewhat towards the outer edge of the non-illumination surface 23 of the atomizing oscillator 21, rather than in the center. The thermistor elements 31 are chip thermistors, which are smaller and lighter than the ceramic piezoelectric material (atomizing oscillator 21). In this embodiment, the planar size and weight of the thermistor element 31 are set to be 1 / 10 or less, preferably 1 / 20 or less, of the ceramic piezoelectric material (atomizing vibrator 21). This allows the thermistor element 31 to be mounted without adversely affecting the vibration characteristics of the atomizing vibrator 21. The thermistor element 31 in this embodiment is a PTC thermistor whose resistance value rapidly increases when the vibrator temperature exceeds a predetermined temperature. The thermistor element 31 detects the heat of the atomizing vibrator 21 and outputs a second DC signal to the central processing unit 50 (see Figure 4).

[0027] Next, the electrical configuration of the ultrasonic atomizer oscillation unit 20 will be described.

[0028] As shown in Figure 4, the ultrasonic atomizer oscillation unit 20 includes an oscillation board 40, which has a DC power supply 42, an oscillation circuit 43, a first resistor voltage divider circuit 44, a full-wave rectifier circuit 45, and a second resistor voltage divider circuit 46. The DC power supply 42 is a power source for supplying DC (24V) to the oscillation circuit 43 and the second resistor voltage divider circuit 46. This 24V DC can be obtained by AC-DC conversion of AC supplied from a commercial AC power supply 41.

[0029] The oscillation circuit 43 generates a high-frequency alternating current (20V to 23V) for oscillator oscillation from DC and outputs it to the atomizing transducer 21. As a result, the atomizing transducer 21 generates ultrasonic vibrations due to the high-frequency alternating current output from the oscillation circuit 43, and radiates ultrasonic waves S1 into the atomizing liquid A1 in the processing tank 11. The first resistor voltage divider circuit 44 steps down the alternating current generated by the oscillation circuit 43 by dividing it with resistors so that the voltage value is lower than the drive voltage (5V) of the central processing unit 50 (3.5V). That is, the voltage value of the rectified first DC signal is stepped down to 75% of the drive voltage of the central processing unit 50. The full-wave rectifier circuit 45 rectifies the alternating current stepped down by the first resistor voltage divider circuit 44 and outputs a first DC signal. That is, the voltage value of the rectified first DC signal is set to 3.5V.

[0030] Furthermore, the DC voltage (24V) supplied from the DC power supply 42 to the second resistor voltage divider circuit 46 is converted to 5V by a three-terminal regulator (not shown). The second resistor voltage divider circuit 46 then divides the DC converted by the three-terminal regulator using resistors to step down the voltage to a value (3.5V) lower than the drive voltage (5V) of the central processing unit 50. In other words, the voltage of the second DC signal is stepped down to 75% of the drive voltage of the central processing unit 50. The thermistor element 31 outputs the DC stepped down by the second resistor voltage divider circuit 46 as the second DC signal.

[0031] As shown in Figure 4, the oscillator board 40 has a central processing unit 50, which is a control unit. The central processing unit 50 is composed of a well-known computer consisting of a CPU 51, ROM 52, RAM 53, etc. The CPU 51 is electrically connected to the oscillator circuit 43 and controls the operation of the oscillator circuit 43. The CPU 51 also controls the operation of the oscillator circuit 43 to stop based on changes in at least one of the first DC signal output by the full-wave rectifier circuit 45 and the second DC signal output by the thermistor element 31. More specifically, the CPU 51 controls the operation of the oscillator circuit 43 to stop based on which of the following occurs first: a change of a predetermined value or more in the first DC signal and a change of a predetermined value or more in the second DC signal. Furthermore, the CPU 51 acquires data logs of the voltage values ​​of the first DC signal and the second DC signal and stores them in the RAM 53. The CPU 51 also incorporates an AD converter that converts the analog first DC signal and the second DC signal to digital.

[0032] Next, we will explain the method for atomizing liquid A1 using the ultrasonic atomizer 10.

[0033] First, the atomizing liquid A1 is stored in the processing tank 11, and then the DC power supply 42 of the ultrasonic atomizer 10 is turned on. The CPU 51 of the central processing unit 50 then generates a high-frequency AC for transducer oscillation from the DC supplied by the DC power supply 42 and controls the oscillation circuit 43 to output it to the atomizing transducer 21.

[0034] High-frequency alternating current is then applied to the atomizing transducer 21, causing it to vibrate ultrasonically. As a result, ultrasonic waves S1 are irradiated into the atomizing liquid A1 from the irradiation surface 22 of the atomizing transducer 21. The irradiated ultrasonic waves S1 propagate through the atomizing liquid A1 and reach the liquid surface A2. As a result, ultrasonic energy is concentrated above the atomizing transducer 21 at the liquid surface A2, causing the atomizing liquid A1 to rise. At the leading edge of the risen atomizing liquid A1, a portion of the atomizing liquid A1 is atomized and scattered as mist (droplets). As a result, the humidity of the space in which the ultrasonic atomizer 10 is installed is controlled.

[0035] Furthermore, even if some atomizing liquid A1 remains in the processing tank 11 once the humidity of the space reaches the desired value, the heat generated by the operating atomizing transducer 21 will gradually evaporate the remaining atomizing liquid A1. Once the remaining atomizing liquid A1 has completely evaporated, the atomizing transducer 21 will enter a dry-run state. Similarly, if the user accidentally operates the ultrasonic atomizer 10 without adding the atomizing liquid A1, the atomizing transducer 21 will also enter a dry-run state. In these situations, the risk of the atomizing transducer 21 malfunctioning due to excessive heat increases.

[0036] In this embodiment, the CPU 51 constantly monitors the voltage value of the first DC signal output by the full-wave rectifier circuit 45. In addition to the voltage value of the first DC signal, the CPU 51 also constantly monitors the voltage value of the second DC signal output by the thermistor element 31. The CPU 51 then controls the operation of the oscillation circuit 43 to stop at the earlier of the following two timings: when the voltage value of the first DC signal exceeds a first threshold (3.85V in this embodiment), or when the voltage value of the second DC signal exceeds a second threshold (in this embodiment, the voltage value when the temperature detection value of the thermistor element 31 reaches 100°C). Note that the atomizing transducer 21 becomes unstable when it reaches approximately 100°C and fails when it reaches approximately 150°C. Incidentally, the first threshold in this embodiment is set to a value lower than the drive voltage (5V) of the central processing unit 50, for example, 90% or less of the said voltage, preferably 85% or less, and more preferably 75% to 80%. Furthermore, the second threshold in this embodiment is also set to a value lower than the drive voltage (5V) of the central processing unit 50, for example, 90% or less of the said voltage, preferably 85% or less, and more preferably 75% to 80%. If the voltage values ​​indicating these thresholds are set too high, the voltage value of the first DC signal or the second DC signal may rise above the input value upper limit of 5V. Conversely, if the voltage values ​​indicating these thresholds are set too low, it may become difficult to accurately detect changes in the first DC signal or the second DC signal.

[0037] For example, when the voltage value of the first DC signal is below the first threshold, the CPU 51 continues to operate the oscillation circuit 43. On the other hand, when the voltage value of the first DC signal exceeds the first threshold, the CPU 51 controls the oscillation circuit 43 to stop operation and stops the atomization of the atomizing liquid A1 by the atomizing vibrator 21.

[0038] Furthermore, when the voltage value of the second DC signal is below the second threshold, the CPU 51 continues the operation of the oscillation circuit 43. On the other hand, when the voltage value of the second DC signal exceeds the second threshold, the CPU 51 controls the operation of the oscillation circuit 43 to stop, thereby stopping the atomization of the atomizing liquid A1 by the atomizing vibrator 21.

[0039] Next, we will explain the methods and results of the verification tests conducted on the atomizing transducer and oscillation substrate.

[0040] In this verification test, the measurement samples were first prepared as follows: Twenty atomizing transducers identical to the atomizing transducer 21 of this embodiment were prepared and designated as transducers "No. 1" to "No. 20" (see Figure 5). In addition, five oscillation boards identical to the oscillation board 40 of this embodiment were prepared and designated as boards "1" to "5" (see Figure 5).

[0041] Then, one atomizing transducer was selected from 20 atomizing transducers, and one oscillation board was selected from 5 oscillation boards. These were then combined and electrically connected to assemble a measurement sample for the ultrasonic atomizer. Since it was possible to combine the atomizing transducers and oscillation boards in 100 different ways (i.e., 20 transducers x 5 boards = 100 combinations), the following verification tests were conducted for all of these combinations.

[0042] In the verification test, tap water, which is the atomizing liquid A1, was first added to the processing tank 11 of the assembled measurement sample. In this state, the atomizing transducer was operated for 1 minute (atomization operation with water), and ultrasonic waves S1 were irradiated from the atomizing transducer toward the liquid surface A2 of the atomizing liquid A1 stored in the processing tank 11. Simultaneously with the start of irradiation, the CPU 51 of the central processing unit 50 was instructed to monitor the voltage value (3.5V) of the first DC signal. Then, after 1 minute had elapsed since the start of irradiation, it was investigated whether the oscillation circuit 43 was operating normally. As a result, it was confirmed that for all 100 combinations, the voltage value of the first DC signal did not exceed the first threshold (3.85V) even after 1 minute had elapsed, indicating that it was operating normally. Based on these results, it was confirmed in advance that all 20 atomizing transducers and 5 oscillation boards were operating normally. The first threshold is set to a voltage value that does not cause the atomizing transducer to stop operating normally.

[0043] Next, the atomizing transducer was operated (dry-fired) with no atomizing liquid A1 in the processing tank 11. Simultaneously with the start of ultrasonic irradiation S1 from the atomizing transducer, the CPU 51 was instructed to monitor the voltage value of the first DC signal and the voltage value of the second DC signal output by the thermistor element 31. The operation of the oscillation circuit 43 was stopped and ultrasonic irradiation from the atomizing transducer was stopped at the earlier of the following timings: when the voltage value of the first DC signal exceeded the first threshold, or when the voltage value of the second DC signal exceeded the second threshold (the voltage value when the thermistor element 31 reaches 100°C). When the atomizing transducer stopped because the voltage value exceeded the first threshold, the voltage value (V) at the time the atomizing transducer stopped and the time (seconds) from when the atomizing transducer started to stop were recorded. The results are shown in Figure 5. Furthermore, when the voltage value exceeded the second threshold (i.e., the temperature detection value of the thermistor element 31 exceeded 100°C) and the atomizing vibrator stopped, the time (in seconds) from when the atomizing vibrator started operating until it stopped was recorded, and the letters "TH," which represent the thermistor element, were also noted. The results are shown in Figure 5.

[0044] As shown in the table in Figure 5, when a dry run was performed, it was confirmed that for all 100 combinations of atomizing vibrator and oscillation board, the operation of the oscillation circuit 43 stopped before 1 minute had elapsed, and the atomizing vibrator stopped. The probability that the atomizing vibrator stopped when the voltage value of the first DC signal exceeded the first threshold was 80% (80 out of 100 cases). In other words, in most of the 100 combinations, the voltage value of the first DC signal exceeded the first threshold earlier than the voltage value of the second DC signal exceeded the second threshold. Incidentally, the time required from the voltage value of the first DC signal exceeding the first threshold until the atomizing vibrator stopped was a minimum of 4 seconds and a maximum of 24 seconds. It was inferred that this difference in required time was due to variations (individual differences) in the physical properties of the atomizing vibrator and oscillation board, which are not exactly the same.

[0045] Furthermore, the probability that the atomizing oscillator would stop due to the temperature detection value of the thermistor element 31 exceeding 100°C was 20% (20 out of 100 cases). In other words, in some of the 100 combinations, the voltage value of the second DC signal exceeded the second threshold earlier than the voltage value of the first DC signal exceeded the first threshold. Incidentally, the time required from the voltage value of the second DC signal exceeding the second threshold until the atomizing oscillator stopped was a minimum of 15 seconds and a maximum of 25 seconds. Here again, it was inferred that this difference in required time was due to variations (individual differences) in the physical properties of the atomizing oscillators and oscillation substrates, which are not exactly the same.

[0046] As can be seen from the results of the verification tests above, in this embodiment, the operation of the oscillation circuit 43 stops and the atomizing vibrator stops no later than 30 seconds before elapsed. Therefore, it was found that damage to the oscillation circuit and atomizing vibrator can be minimized, and the risk of failure is significantly reduced.

[0047] Furthermore, in the verification test, the atomizing transducer was operated (dry run) with the atomizing transducer disconnected for each of the substrates "1" to "5". Simultaneously with the start of ultrasonic wave S1 irradiation from the atomizing transducer, the CPU 51 was instructed to monitor the voltage value of the first DC signal and the voltage value of the second DC signal output by the thermistor element 31. As a result, since the temperature of the atomizing transducer did not rise at all, no increase in the voltage of the second DC signal was observed. On the other hand, for all five oscillation substrates, the voltage value of the first DC signal exceeded the first threshold before one minute had elapsed, confirming that the oscillation circuit stopped working and the atomizing transducer stopped. Note that this result is omitted from Figure 5.

[0048] Therefore, according to this embodiment, the following effects can be obtained.

[0049] (1) In the ultrasonic atomizer 10 equipped with the ultrasonic atomizer oscillation unit 20 of this embodiment, the CPU 51 of the central processing unit 50 simultaneously monitors the first DC signal obtained by stepping down and rectifying the AC generated by the oscillation circuit 43, and the second DC signal obtained by the thermistor element 31. In other words, the CPU 51 not only directly monitors the voltage change of the AC generated by the oscillation circuit 43, but also directly monitors the temperature change of the atomizing transducer 21. The CPU 51 then controls the operation of the oscillation circuit 43 to stop before a failure occurs, based on the change in at least one of the two monitored targets, the first DC signal and the second DC signal. Therefore, unlike the case where the operation is stopped based on the change in only one monitored target, it is possible to reliably prevent both failure of the atomizing transducer 21 and failure of the oscillation board 40. In particular, in this embodiment, the control to stop the operation of the oscillation circuit 43 is performed based on which of the following occurs first: a change in the voltage value of the first DC signal exceeding a predetermined value or a change in the voltage value of the second DC signal exceeding a predetermined value. Therefore, the operation of the oscillation circuit 43 can be stopped quickly, making it possible to more reliably prevent the occurrence of malfunctions.

[0050] (2) When using the ultrasonic atomizer oscillation unit 20 having an oscillation board 40 and an atomizing transducer 21, the task of connecting or disconnecting the oscillation board 40 and the atomizing transducer 21 is basically left to the user. Therefore, the user may accidentally operate the ultrasonic atomizer 10 with the transducer disconnected. In this case, an abnormal voltage is applied to the circuit side of the oscillation board 40, resulting in a dry-firing state, which may cause the resistors and other components constituting the circuit to burn out and the oscillation board 40 to fail. In this embodiment, when the first DC signal from the oscillation circuit 43 exceeds a first threshold (3.85V) during a dry-firing state, the CPU 51 controls the operation of the oscillation circuit 43 to stop it. As a result, the first DC signal with a high voltage does not flow from the oscillation circuit 43, thus preventing failure of the oscillation board 40 in advance and reliably.

[0051] (3) For example, a conventional technique has been proposed in which a float switch (not shown) is installed in the processing tank 11, and the DC power supply 42 for the atomizing transducer 21 is turned on and off by detecting the water level of the atomizing liquid A1 with the float switch. However, since the float switch is optional, some users operate the atomizing transducer 21 without using the float switch. In this case, if the user forgets to turn off the DC power supply 42 and the atomizing transducer 21 continues to operate, there will be no atomizing liquid A1 in the processing tank 11, and the atomizing transducer 21 will malfunction. In this embodiment, the CPU 51 stops the operation of the oscillation circuit 43 when the first DC signal from the oscillation circuit 43 exceeds a first threshold (3.85V). Alternatively, the CPU 51 stops the operation of the oscillation circuit 43 when the second DC signal from the thermistor element 31 exceeds a second threshold (the voltage value when the thermistor detection temperature reaches 100°C). This control method stops the atomizing transducer 21, thereby preventing failure of the atomizing transducer 21 in advance and reliably.

[0052] (4) In this embodiment, a second DC signal is obtained by the thermistor element 31, which is a temperature sensor, and increases or decreases in direct conjunction with the temperature change of the atomizing vibrator 21. Therefore, excessive heat generation of the atomizing vibrator 21 can be detected accurately and quickly. In particular, since the thermistor element 31 is directly attached to the atomizing vibrator 21, it can quickly detect rapid temperature changes of the atomizing vibrator 21. In addition, since the voltage value of the obtained second DC signal is lower than the drive voltage of the CPU 51 under normal conditions, it can be taken in as an input signal to the CPU 51 and monitored. Furthermore, the thermistor element 31 is mounted on the non-irradiated surface 23. Therefore, the energized parts of the thermistor element 31 and the sensor terminals 27 do not come into contact with the atomizing liquid 15, making it easier to route the wiring 33. In addition, the mounted thermistor element 31 is sufficiently small and light compared to the atomizing vibrator 21, and is positioned to avoid the center where the amplitude is large. Therefore, even if the thermistor element 31 is present, there is no risk of it adversely affecting the ultrasonic waves emitted from the irradiation surface 22.

[0053] The above embodiment may be modified as follows.

[0054] In the above embodiment, the CPU 51 may detect heat generation in the atomizing transducer 21 using two thermistor elements: a thermistor element 31 for detecting the transducer temperature of the atomizing transducer 21, and a thermistor element for detecting the ambient temperature. Even in this case, the CPU 51 can reliably prevent failure of the atomizing transducer 21 by stopping the operation of the oscillation circuit 43 when heat generation is detected. Note that the transducer temperature of the atomizing transducer 21 may be affected by the ambient temperature. In contrast, by using a thermistor element for detecting the ambient temperature, the heat generation status of the atomizing transducer 21 can be accurately detected without being affected by the ambient temperature.

[0055] In the above embodiment, the CPU 51 controlled the oscillation circuit 43 to stop operating when the voltage values ​​of the DC signals (first DC signal and second DC signal) exceeded thresholds (first threshold and second threshold). However, the CPU 51 may also control the oscillation circuit 43 to stop operating when, for example, the rate of temperature rise of the atomizing vibrator 21 exceeds a threshold (i.e., when the temperature rise is steeper than usual).

[0056] In the above embodiment, the CPU 51 of the central processing unit 50 may acquire data logs of the voltage value of the first DC signal output by the full-wave rectifier circuit 45 and the voltage value of the second DC signal output by the thermistor element 31 and store them in the RAM 53 (data logger). For example, the data log when dry-heating occurs may be stored in the RAM 53, and the CPU 51 may refer to the data log stored in the RAM 53 when making a determination of the voltage value in subsequent instances. If the RAM 53 stores information such as "In case A, it exceeded XV, in case B, it exceeded YV,...", then if the user misuses the device multiple times and experiences dry-heating symptoms multiple times, the system can inform the user, for example, "How many more times can it dry-heat before it breaks?".

[0057] In the above embodiment, a recess 16 was formed in the bottom 12 of the processing tank 11, and the atomizing vibrator 21 was installed in the recess 16. However, the installation method of the atomizing vibrator 21 may be changed. For example, the recess 16 may be omitted, and the atomizing vibrator 21 may be installed on the bottom 12 of the processing tank 11. In addition, although the recess 16 in the above embodiment was formed in the center of the bottom 12, it may also be formed on the outer periphery of the bottom 12.

[0058] In the above embodiment, the AC voltage stepped down by the first resistor voltage divider circuit 44 was rectified by the full-wave rectifier circuit 45 to obtain the first DC signal, but the embodiment is not limited to this. For example, the first DC signal may be obtained by rectifying with a half-wave rectifier circuit.

[0059] In the above embodiment, the AC voltage stepped down by the first resistor voltage divider circuit 44 was rectified by the full-wave rectifier circuit 45 to obtain the first DC signal, but the embodiment is not limited to this. For example, the AC voltage may be rectified by the full-wave rectifier circuit 45 to obtain DC voltage, and then stepped down by the first resistor voltage divider circuit 44 to obtain the first DC signal.

[0060] In the above embodiment, a CPU 51 with a built-in AD converter that converts the analog first DC signal and second DC signal to digital was used, but the system is not limited to this. For example, if a CPU 51 without a built-in AD converter is used, an AD converter circuit may be provided in front of the CPU 51 to convert the first DC signal and second DC signal to digital.

[0061] In the above embodiment, a thermistor element 31 was used as a temperature sensor to detect the temperature rise of the atomizing transducer 21, but the invention is not limited to this. For example, an electrical and contact-type temperature sensor other than thermistor element 31 may be used.

[0062] In the above embodiment, tap water was used as the atomizing liquid A1 stored in the treatment tank 11, but it is not limited to this, and pure water or hypochlorous acid water may also be used.

[0063] • In the above embodiment, an example was shown in which the ultrasonic atomizer oscillation unit 20 is used in an ultrasonic atomizer 10 for humidifying a space, but it is not limited to this and may be used in other ultrasonic atomizers. For example, the ultrasonic atomizer oscillation unit 20 may be used in an ultrasonic atomizer that atomizes chemical solutions for deodorizing or disinfecting a space.

[0064] Next, in addition to the technical ideas described in the claims, the technical ideas that can be grasped by the embodiments described above are listed below.

[0065] (1) The oscillation unit for an ultrasonic atomizer according to claim 5 or 6, characterized in that the thermistor element is a chip thermistor smaller than the ceramic piezoelectric material.

[0066] (2) The oscillator unit for an ultrasonic atomizer according to claim 5 or 6, characterized in that the thermistor element is mounted on the non-irradiated surface in a manner that avoids the formation of the terminals for driving the atomizing transducer.

[0067] (3) The oscillator unit for an ultrasonic atomizer according to claim 1, wherein the oscillator board has a rectifier circuit that rectifies the AC generated and stepped down by the oscillator circuit and outputs the first DC signal, the temperature sensor is a thermistor element that is mounted on a non-irradiated surface opposite to the irradiation surface to detect the oscillator temperature when energized, and the control unit acquires and stores a data log of the voltage value of the first DC signal output by the rectifier circuit and a data log of the voltage value of the second DC signal output by the thermistor element.

[0068] (4) The oscillator unit for an ultrasonic atomizer according to claim 3, characterized in that the drive voltage of the central processing unit is 5V, and the voltage value of the first DC signal after rectification is set to be 3V or more and 4V or less under normal conditions.

[0069] (5) The oscillator unit for an ultrasonic atomizer according to any one of claims 3 to 6, wherein the central processing unit has an AD conversion function that converts the first DC signal from analog to digital. [Explanation of Symbols]

[0070] 10…Ultrasonic atomizer 20…Oscillator unit for ultrasonic atomizer 21...Atomization vibrator 22…Irradiation surface 23…Non-irradiated surface 31...Thermistor element as a temperature sensor 40…Oscillator board 43…Oscillator circuit 44...First resistive voltage divider circuit as a resistive voltage divider circuit 45...Full-wave rectifier circuit as a rectifier circuit 50...Central Processing Unit as Control Unit A1…Liquid for atomization

Claims

1. An atomizing vibrator having an irradiation surface positioned in contact with the atomizing liquid, An oscillator board having an oscillator circuit that generates a high-frequency AC for oscillatory use from DC and outputs it to the atomizing oscillator, and a control unit that controls the operation of the oscillator circuit, An oscillator unit for an ultrasonic atomizer, comprising: The control unit monitors a first DC signal obtained by stepping down and rectifying the AC generated by the oscillation circuit, and a second DC signal obtained by a temperature sensor installed on the atomizing vibrator. Based on changes in at least one of the first DC signal and the second DC signal, the control unit performs control to stop the operation of the oscillation circuit. An oscillator unit for an ultrasonic atomizer, characterized by the following features.

2. The ultrasonic atomizer oscillation unit according to claim 1, characterized in that it controls the operation of the oscillation circuit to stop based on which of the following occurs first: a change in the first DC signal exceeding a predetermined value and a change in the second DC signal exceeding a predetermined value.

3. The control unit is a central processing unit, The oscillator board includes a resistor voltage divider circuit that divides the AC generated by the oscillator circuit using resistors to reduce its voltage to a value lower than the drive voltage of the central processing unit, and a rectifier circuit that rectifies the AC reduced by the resistor voltage divider circuit to output the first DC signal. The ultrasonic atomizing unit according to feature 2.

4. The central processing unit, which is the control unit, The voltage value of the first DC signal output by the rectifier circuit is monitored. The operation of the oscillation circuit continues when the voltage value is less than or equal to the first threshold, and the operation of the oscillation circuit stops when the voltage value exceeds the first threshold. The ultrasonic atomizing unit according to feature 3.

5. The control unit is a central processing unit, The atomizing vibrator is a flat ceramic piezoelectric body having a non-irradiated surface on the opposite side of the irradiation surface. The temperature sensor is a thermistor element mounted on the non-irradiated surface to detect the oscillator temperature when energized, and outputs the second DC signal with a voltage value lower than the drive voltage of the central processing unit. The ultrasonic atomizing unit according to feature 2.

6. The central processing unit, which is the control unit, The voltage value of the second DC signal output by the thermistor element is monitored. The operation of the oscillation circuit continues when the voltage value is less than or equal to the second threshold, and the operation of the oscillation circuit stops when the voltage value exceeds the second threshold. The ultrasonic atomizer oscillation unit according to feature 5.

7. An ultrasonic atomizer comprising an ultrasonic atomizer oscillation unit according to any one of claims 1 to 6.

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