JP2008126099A - Degassing apparatus and degassing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a degassing apparatus capable of accelerating efficient degassing by well floating air bubbles in one degassing time from the oscillation of an ultrasonic vibrator to the stop thereof, and a degassing method. <P>SOLUTION: In the degassing apparatus for irradiating the liquid 2 in a washing tank 1 with an ultrasonic wave by the ultrasonic oscillator 10 and the ultrasonic vibrator 4, the ultrasonic oscillator 10 is equipped with a microcomputer 11 for respectively outputting a 0/1 signal A, which forms frequency by modulating the oscillation frequency to the ultrasonic vibrator 4 and an ON/OFF signal B for repeating the oscillation/stop of the ultrasonic vibrator 4 to irradiate the liquid 2 a plurality of times to irradiate the liquid with an ultrasonic wave, DDS12 for inputting the 0/1 signal A of the microcomputer 11 to form a signal waveform C for driving the ultrasonic vibrator 4, a drive IC13 for outputting a drive signal D for processing the signal waveform C according to the ON/OFF signal B and an output means 14 for inputting the drive signal D of the drive IC13 to apply switching power E for repeating the stop and oscillation of the ultrasonic vibrator 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a deaeration apparatus and method, and more particularly, a deaeration in which a gas existing in a liquid is deaerated by irradiating ultrasonic waves with an ultrasonic vibrator in order to improve the cleaning power for an object to be cleaned. The present invention relates to a gas apparatus and method.

Conventionally, deaerators generally improve the cleaning power for objects to be cleaned (substrates for electronic devices such as semiconductor wafer substrates and LCD glass substrates) when ultrasonic cleaning is performed using the degassed liquid. Is known and has been often adopted as such a cleaning technique. And, as a conventional deaeration device, the sound pressure of the ultrasonic wave irradiated to the liquid is continuously modulated by modulating the ultrasonic wave irradiated from the ultrasonic vibrator to the liquid in the cleaning tank to a predetermined frequency bandwidth. A structure in which the period of distribution is continuously changed to relax and extinguish an ultrasonic standing wave is well known (see, for example, Patent Document 1).
JP, 11-290611, A Embodiment by the structure mentioned above is described with reference to FIG. 6 and FIG. FIG. 6 is a diagram schematically illustrating the ultrasonic sound pressure distribution 2a and the defoaming 2b action over time in the liquid 2 according to an embodiment of the conventional degassing apparatus. FIG. 7 is a diagram showing a sound pressure distribution 2a whose period continuously changes in the liquid 2 shown in FIG.

  As shown in FIG. 6, the conventional deaeration device is formed so as to propagate ultrasonic waves from the ultrasonic transducer 4 attached to the bottom of the cleaning tank 1 to the internal liquid 2. An ultrasonic oscillator 20 capable of continuously modulating the frequency irradiated to the liquid to a predetermined frequency bandwidth is connected to the ultrasonic transducer 4. In the conventional degassing method using such an apparatus, a dense wave is formed by irradiation of continuous ultrasonic waves periodically modulated in the liquid 2 to generate a sound pressure distribution 2a. The sound pressure distribution 2a composed of the maximum sound pressure band point c and the minimum sound pressure band point d moves in the liquid 2 in small increments with time. Further, as shown in FIG. 7, the sound pressure distribution 2a that moves with the passage of time has a reference frequency of the wavelength λ, a high frequency band of the wavelength λ1, and a low frequency band of the wavelength λ2 due to the dense wave propagating in the liquid 2. As shown in the figure, the wavelengths λ, λ1, λ2,. . . A standing wave is generated by the continuous sound pressure distribution 2a at every interval of λn, and the entire cavitation in which the liquid 2 uniformly contacts the air layer is generated. Therefore, the bubbles 2b in the liquid 2 are frequently crowded and fused by the cavitation generated so as to move evenly in the liquid 2, and can grow into a single bubble, and can quickly float and separate. Deaeration can be realized.

  As described above, in the conventional degassing apparatus and method, the ultrasonic wave irradiated from the ultrasonic transducer 4 is modulated to continuously change the period of the sound pressure distribution 2 a in the liquid 2. Cavitation that moves evenly occurred, and the bubbles 2b were lifted up by this cavitation to be quickly lifted and removed while being frequently crowded and grown.

  However, in the conventional degassing apparatus and method, when the liquid 2 is degassed, as shown in FIG. 6, within one degassing time from the oscillation to the stop of the ultrasonic vibrator 4, the reference frequency, Since the low frequency band and the high frequency band are continuously propagated without stopping and the cavitation is always moved in the liquid 2, the fine bubbles 2 b are formed in the liquid 2 unless the oscillation of the ultrasonic vibrator 4 is stopped. Diffusing without crowding, it was difficult to float all the bubbles 2b in a short time. In this case, after completing continuous irradiation of the liquid 2 with the reference frequency, the low frequency band, and the high frequency band, the fine bubbles 2b are not formed until the oscillation of the ultrasonic vibrator 4 is stopped and the liquid 2 is stabilized. Since the assemblage and ascend, it takes time to ascend, and for example, when it is not possible to ascend, it is necessary to deaerate repeatedly by repeating oscillation and stop of restarting oscillation and generating new cavitation. Therefore, in the conventional degassing apparatus and method, the degassing efficiency is improved because the long degassing time by continuous ultrasonic irradiation is repeatedly degassed from the ultrasonic transducer 4 a plurality of times according to the removal state of the bubbles 2b. Unfortunately, there was a problem that the deaeration process took a long time to shift to the cleaning process and production was delayed overall.

  The present invention has been made in view of the above points, and an object of the present invention is to efficiently deaerate bubbles in a liquid by allowing the bubbles in the liquid to rise well within one deaeration time from the oscillation to the stop of the ultrasonic vibrator. It is an object of the present invention to provide a deaeration device and method capable of promoting the above.

  The present invention has been made to solve the above-described problems, and is a deaeration device for degassing a liquid in a cleaning tank by irradiating ultrasonic waves with an ultrasonic oscillator and an ultrasonic vibrator. Oscillates ultrasonic waves from an ultrasonic transducer with a 0/1 signal that can form a frequency that is continuously modulated to a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic waves emitted from the ultrasonic transducer A microcomputer that outputs ON / OFF signals that repeatedly irradiate a plurality of stops, a DDS that generates a signal waveform that drives an ultrasonic transducer by inputting a 0/1 signal of the microcomputer, and a microcomputer ON / OFF Input the OFF signal and the DDS signal waveform, and output the drive signal that processes the signal waveform according to the ON / OFF signal, and the drive IC drive signal Applying switching power to the ultrasonic transducer and repeating the ON / OFF signal with the signal waveform according to the signal ON and the oscillation when the signal is OFF repeats multiple times within one degassing time. And an output stage for irradiation.

  The degassing method according to the present invention is a degassing method in which a liquid in a cleaning tank is degassed by irradiating ultrasonic waves with an ultrasonic oscillator and an ultrasonic vibrator, and the ultrasonic oscillator microcomputer performs ultrasonic vibration. Repeatedly oscillate / stop ultrasonic waves from an ultrasonic transducer with 0/1 signal that can form a frequency that is continuously modulated to a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic wave emitted from the child. A first step of outputting ON / OFF signals to be irradiated, and a second step of generating a signal waveform for driving the ultrasonic transducer by inputting the 0/1 signal of the microcomputer by the DDS of the ultrasonic oscillator, A drive IC of the ultrasonic oscillator inputs a microcomputer ON / OFF signal and a DDS signal waveform, and outputs a drive signal for processing the signal waveform according to the ON / OFF signal. The output stage of the ultrasonic oscillator inputs the drive signal of the drive IC, applies the switching power to the ultrasonic transducer, and stops when the signal is turned on by the signal waveform according to the ON / OFF signal and when the signal is turned off And a fourth step of intermittently irradiating the ultrasonic wave by repeating the oscillation a plurality of times within one deaeration time.

  As described above, according to the deaeration apparatus and method of the present invention, the modulated signal waveform C is turned on / off signal B within the time for deaeration by irradiating the ultrasonic wave from the ultrasonic transducer 4 once. In order to irradiate ultrasonic waves intermittently by repeating the oscillation and stop a plurality of times, the bubbles 2b that cannot rise in the liquid 2 are gathered and easily floated and disappeared at each stop time that is repeated a plurality of times stepwise. This makes it possible to efficiently degas the liquid 2 within one degassing time by the ultrasonic transducer 4, thereby shortening the degassing time until the cleaning process is started and improving the overall productivity. can do.

  Next, embodiments of a deaeration apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing an embodiment of a deaeration device according to the present invention. FIG. 2 is a diagram showing an ON / OFF signal B input from the microcomputer 11 shown in FIG. 1 to the drive IC 13. FIG. 3 is a diagram showing a frequency-modulated signal waveform C output from the DDS 12 shown in FIG. FIG. 4 is a diagram showing the drive signal D output from the drive IC 13 by inputting the signal waveform C and the ON / OFF signal B shown in FIG. FIG. 5 is a diagram showing the ultrasonic sound pressure distribution and the defoaming action in the liquid 2 due to the oscillation and stop of the ultrasonic transducer 4 shown in FIG. Here, the cleaning tank 1 (including the liquid 2) and the ultrasonic transducer 4 shown in FIG. 1 are the same constituent elements as those of the prior art shown in FIG. 6, and the same constituent elements are denoted by the same reference numerals. To do.

  As shown in FIG. 1, the embodiment of the deaeration device according to the present invention is ultrasonically applied to the liquid 2 inside from the ultrasonic transducer 4 attached to the bottom of the cleaning tank 1, as in the prior art shown in FIG. 6. Is formed to propagate. The ultrasonic transducer 4 is connected to an ultrasonic oscillator 10 that can continuously modulate the frequency applied to the liquid 2 to a predetermined frequency bandwidth. Here, unlike the prior art shown in FIG. 6, the embodiment of the deaeration device according to the present invention continuously operates the ultrasonic transducer 4 from oscillation to stop by the signal waveform C modulated by the ultrasonic oscillator 10. Instead, the modulated signal waveform C is repeatedly output while being turned on and off a plurality of times so that it can be deaerated by intermittently irradiating ultrasonic waves.

Here, as shown in FIG. 1, the ultrasonic oscillator 10 generates a frequency continuously modulated in a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer 4. A microcomputer 11 for outputting an ON / OFF signal B for irradiating a plurality of ultrasonic oscillations / stops from the ultrasonic transducer 4 together with a 0/1 signal A that can be formed, and a 0/1 signal A of the microcomputer 11 The DDS 12 that generates the signal waveform C that drives the ultrasonic transducer 4 and the ON / OFF signal B of the microcomputer 11 and the signal waveform C of the DDS 12 are input, and the signal waveform C is input according to the ON / OFF signal B. The drive IC 13 that outputs the drive signal D to be processed, and the drive signal D of the drive IC 13 is input and the switching power E is applied to the ultrasonic transducer 4 to turn on / off. An output stage 14 for intermittently irradiating ultrasonic waves by repeating the signal waveform C according to the F signal B when the signal is turned on and the oscillation when the signal is turned off a plurality of times within one deaeration time. Yes.
In other words, the present embodiment includes two connection lines: a signal waveform line connected from the microcomputer 11 to the drive IC 13 via the DDS 12 and an ON / OFF signal line directly connected from the microcomputer 11 to the drive IC 13. In this respect, in addition to the signal waveform line that is continuously driven as in the prior art, an ON / OFF signal line that is intermittently output by turning the signal waveform ON / OFF is provided separately. .

  Specifically, the microcomputer 11 generates the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer 4 as a 0/1 signal A that can be formed into a frequency that is continuously modulated in a predetermined frequency bandwidth by a program. , It is formed so as to be passed to the DDS 12 side. Here, the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer 4 is a frequency that is the center of the oscillation frequency irradiated from the ultrasonic transducer 4 into the liquid 2 while being continuously modulated to a predetermined frequency bandwidth. Thus, 20 KHz to 150 KHz is used. On the other hand, the frequency is modulated by performing a sweep operation within a range of 1% to 50% (for example, within ± 2 KHz). Further, the microcomputer 11 is formed so as to be able to capture in advance information such as individual characteristics of the ultrasonic transducer 4, the natural frequency of the cleaning tank 1, the liquid 2 characteristics, or the amount of bubbles and dissolved air. The microcomputer 11 is configured to output to the DDS 12 the 0/1 signal A given numerically as control data of the modulated frequency based on the various data described above according to a predetermined program.

  Further, the microcomputer 11 outputs the ON / OFF signal B (see FIG. 2) for irradiating the ultrasonic wave repeatedly by oscillating / stopping the ultrasonic transducer 4 together with the output of the 0/1 signal A described above. Is formed. As shown in FIG. 2, the ON / OFF signal B includes an oscillation at the time of signal OFF and a stop at the time of signal ON within one deaeration time in which the ultrasonic transducer 4 emits ultrasonic waves. It is set as a rectangular wave (Hi / Lo signal) that repeats a plurality of times at the same interval and is output to the drive IC 13. The ON / OFF signal B corresponds to the signal waveform C generated based on the 0/1 signal A modulated by the DDS 12 described later when the signal for oscillating the ultrasonic wave is OFF, and the ultrasonic transducer 4 is intermittently connected. Is set as a signal to oscillate and stop automatically.

  Further, the DDS (direct digital synthesizer) 12 is based on the 0/1 signal A which is modulated and given by the microcomputer 11 serving as the control center and is given as a numerical value, as shown in FIG. A signal waveform C is generated as a waveform for oscillating. That is, the DDS 12 operates in accordance with a clock signal (not shown) from the microcomputer 11 and outputs a signal waveform C having a frequency that varies according to a 0/1 signal A given as a numerical value. Therefore, the DDS 12 can adjust the frequency of the signal waveform C precisely and freely according to the numerical control of the microcomputer 11.

  Further, the drive IC 13 inputs and amplifies the ON / OFF signal B and the signal waveform C of the DDS 12 from the microcomputer 11 shown in FIG. 1, respectively, processes the signal waveform C according to the ON / OFF signal B, As shown in FIG. 4, the ultrasonic transducer 4 is formed so as to output a drive signal D that repeats oscillation / stop. Here, as for the drive signal D, the signal waveform C and the ON / OFF signal B are respectively input to the drive IC 13, and the oscillation when the signal is OFF and the stop when the signal is ON are alternately plural within one deaeration time. The output signal is output to the output stage 14 as a driving signal for the ultrasonic transducer 4 to be repeated.

  The output stage 14 amplifies and applies the switching power E to the ultrasonic transducer 4 based on the drive signal D output from the drive IC 13 shown in FIG. 1, and acts as a switching FET during this application. Thus, the signal waveform C according to the ON / OFF signal B is formed so as to alternately turn on and off the oscillation when the signal is OFF and the stop when the signal is ON. That is, the output stage 14 is a switching circuit, amplifies power supplied from a power source 17 and a rectifier circuit 18 to be described later, and exceeds switching power E (high frequency voltage and high frequency current) while being turned on / off according to the drive signal D. The ultrasonic transducer 4 is applied to the ultrasonic transducer 4 and functions to cause the ultrasonic transducer 4 to intermittently irradiate the ultrasonic wave by repeatedly stopping and oscillating a plurality of times within one deaeration time.

  As shown in FIG. 1, the ultrasonic oscillator 10 includes a power source 17 that supplies an AC voltage to the output stage 14, a rectifier circuit 18 that rectifies the AC voltage from the power source 17 into a DC, and an output stage 14. The output transformer 15 that boosts or lowers the voltage of the switching power E (high-frequency voltage and high-frequency current) that is turned on / off output from the power transformer, and the ultrasonic vibrator 4 by correcting the power of the switching power via the output transformer 15 by power factor correction. And a power factor correction unit 16 to be applied. Here, the output transformer 15 receives the switching power E from the output stage 14, boosts or lowers the transformer primary voltage according to the winding ratio, and causes the power factor correction unit 16 to operate based on the transformer secondary voltage. It is formed so that high-frequency power is applied to the ultrasonic transducer 4 by being interposed. Further, since the ultrasonic vibrator 4 used in the cleaning tank 1 is a piezoelectric element, it is a capacitive load. Therefore, it is necessary to connect the power factor correction unit 16 to the ultrasonic transducer 4 so that the phase difference between the high frequency voltage and the high frequency current is eliminated when driven at the resonance frequency.

A deaeration method according to the present invention in which deaeration is performed using the deaeration device having such a configuration will be described in detail with reference to FIGS. In the deaeration method according to the present invention, as shown in FIG. 1, first, the microcomputer 11 of the ultrasonic oscillator 10 performs a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer 4. And a 0/1 signal A that can form a frequency that is continuously modulated, and an ON / OFF signal B that repeatedly irradiates / stops ultrasonic waves from the ultrasonic transducer 4. Perform steps.
At this time, the frequency modulation in the microcomputer 11 that outputs the 0/1 signal A is, for example, a frequency of 5% with respect to the reference frequency of 40 KHz as described in Patent Document 1 of the related art described above. When the modulation bandwidth is set, the low frequency side of 39 KHz and the high frequency side of 41 KHz are continuously and alternately modulated, and the sound in the liquid 2 is continuously modulated by a predetermined modulation period, for example, 60 times per second. The pressure distribution can be continuously moved in small increments to improve the deaeration (defoaming) efficiency. The frequency bandwidth to be modulated is preferably in the range of 0.1% to 100% with respect to the reference frequency value, and particularly preferably in the range of 1% to 50% with respect to the reference frequency value. The modulation period of ultrasonic irradiation is preferably used in the range of 1 to 2000 times per second. These frequency bandwidths and modulation periods may be appropriately determined according to the shape and size of the cleaning tank 1, the liquid properties such as the viscosity and composition of the liquid 2, the bubbles contained in the liquid 2, the amount of dissolved air, and the like. it can.
When the microcomputer 11 outputs the ON / OFF signal B, the modulation data of the 0/1 signal A described above, the individual characteristics of the ultrasonic transducer 4 input in advance, the natural frequency of the cleaning tank 1, the liquid The ON / OFF signal B is set based on two types of information or various information such as bubbles and dissolved air amount. Specifically, the microcomputer 11 calculates, for example, a single degassing time (60 seconds to 600 seconds) when the ultrasonic wave is continuously emitted from the ultrasonic transducer 4 with the modulated ultrasonic waves described above. The ON / OFF signal B is set so that the oscillation and stop of the ultrasonic wave are repeated at least twice (plural). That is, a single deaeration time from the continuous oscillation to the stop shown in FIG. 6 and a single deaeration time until the oscillation is completely stopped by repeating the oscillation and the stop shown in FIG. Are almost identical and matched.

  Next, when the 0/1 signal A is output from the microcomputer 11 in the first step, the 0/1 signal A is input to the DDS 12 of the ultrasonic oscillator 10 to drive the ultrasonic transducer 4 shown in FIG. The second step of generating the signal waveform C subjected to frequency modulation is executed. The DDS 12 is driven by a clock signal (not shown) of the microcomputer 11 and outputs a signal waveform C having a modulated frequency that changes in accordance with a numerically given 0/1 signal A to the drive IC 13. Here, the signal waveform C is generated into a waveform such as a rectangular wave as shown in FIG. 2 or a sine wave as shown in FIG.

  Next, when the ON / OFF signal B from the microcomputer 11 and the signal waveform C from the DDS 12 are respectively output in the first and second steps, both pieces of information are respectively input to the drive IC 13 of the ultrasonic oscillator 10. Then, the third step of outputting the drive signal D for processing the signal waveform C according to the ON / OFF signal B is executed. That is, the two frequency components of the signal waveform C modulated for the first time via the drive IC 13 and the ON / OFF signal B to be oscillated / stopped are merged into one, and the drive signal repeats a plurality of stop / oscillations shown in FIG. Output as D.

Then, when the drive signal D is output from the drive IC 13 in the third step, the drive signal D is input to the output stage 14 which is a switching FET of the ultrasonic oscillator 10 and the switching power (high-frequency voltage and high-frequency current) is supplied to the ultrasonic transducer 4. ), And at the time of this application, a switching operation in which the signal waveform C according to the above-described ON / OFF signal B is repeatedly turned on and stopped when the signal is turned off within a single degassing time. A fourth step is performed in which the ultrasonic transducer 4 irradiates ultrasonic waves intermittently.
Here, in the fourth step, when switching power is applied from the output stage 14 to the ultrasonic transducer 4, as shown in FIG. 1, first, an AC voltage from the power source 17 is supplied to the rectifier circuit 18 to be converted to DC. By rectifying and amplifying the output stage 14, it is transmitted to the output transformer 15 as switching power E. In the output transformer 15, the transmitted voltage of the switching power E is stepped up or stepped down as a transformer primary side voltage according to the winding ratio, and the transformer secondary side voltage is supplied via the power factor correction unit 16. To do. Thereafter, the switching power is applied to the ultrasonic transducer 4 as high frequency power.

  In this way, the drive signal D shown in FIG. 4 is input from the drive IC 13 to the output stage 14, and finally the liquid 2 is repeatedly oscillated and stopped a plurality of times within one deaeration time by the ultrasonic transducer 4. As shown in FIG. 5, the oscillation and the stop are repeated a plurality of times within one deaeration time, and bubbles are generated from the liquid 2 in the cleaning tank 1 at this stop. 2b can be levitated and efficiently removed step by step.

As mentioned above, although embodiment of the deaeration apparatus and method by this invention was described in detail, this invention is not limited to embodiment mentioned above, It can change in the range which does not deviate from the summary.
For example, a single deaeration time in the case of continuously irradiating ultrasonic waves modulated by the ultrasonic vibrator is calculated, and at least two times (a plurality) of oscillation and stop of the ultrasonic waves within this time. The embodiment in which the ON / OFF signal is set to be repeated has been described in detail. However, the present invention is not limited to this, and the deaeration time for one continuous irradiation is not calculated. The ON / OFF signal can be set so that oscillation and stop are repeated a plurality of times within a free time. Specifically, the time that can be set by the microcomputer is the oscillation time (Lo time) shown in FIG. 2 and the merge time (Hi + Lo time) in which oscillation and stop are executed in pairs. (Hi time) is set to be determined arbitrarily. Here, the oscillation time is usually set to 0.3 seconds to 1 second, and the merge time is set to 1.3 to 5 seconds. By repeating the merge time for oscillating and stopping under these conditions, It is possible to freely set a single degassing time of 60 to 600 seconds or any other time.

The block diagram which shows embodiment of the deaeration apparatus by this invention. The figure which shows the ON / OFF signal input into drive IC from the microcomputer shown in FIG. The figure which shows the signal waveform to which the frequency modulation output from DDS shown in FIG. 1 was applied. The figure which shows the drive signal which inputs the signal waveform C shown in FIG. 1, and the ON / OFF signal B, and is output from drive IC. The figure which shows the ultrasonic sound pressure distribution and defoaming effect | action in a liquid by the oscillation and a stop of the ultrasonic transducer | vibrator shown in FIG. The figure which shows modeled the sound pressure distribution and defoaming effect | action of the ultrasonic wave with the time passage in the liquid by one Embodiment of the conventional deaeration apparatus. The figure which shows the sound pressure distribution from which the period changes continuously in the liquid shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Washing tank 2 Liquid 4 Ultrasonic vibrator 10 Ultrasonic oscillator 11 Microcomputer 12 DDS
13 Drive IC
14 Output Stage 15 Output Transformer 16 Power Factor Correction Unit 17 Power Supply 18 Rectifier Circuit

Claims (2)

In the deaeration apparatus for deaeration by irradiating the liquid (2) in the cleaning tank (1) with ultrasonic waves by the ultrasonic oscillator (10) and the ultrasonic vibrator (4),
The ultrasonic oscillator (10)
Along with the 0/1 signal (A) that can form a frequency continuously modulated in a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer (4), the ultrasonic wave A microcomputer (11) for outputting an ON / OFF signal (B) for repeatedly irradiating a plurality of oscillations / stops of the ultrasonic waves from the vibrator (4);
A DDS (12: direct digital synthesizer) that inputs a 0/1 signal (A) of the microcomputer (11) and generates a signal waveform (C) for driving the ultrasonic transducer (4);
A drive signal for inputting the ON / OFF signal (B) of the microcomputer (11) and the signal waveform (C) of the DDS (12) and processing the signal waveform (C) according to the ON / OFF signal (B). A drive IC (13) for outputting (D);
The drive signal (D) of the drive IC (13) is input, the switching power (E) is applied to the ultrasonic transducer (4), and the signal waveform (C) according to the ON / OFF signal (B) is applied. The output stage (14) for intermittently irradiating the ultrasonic wave by repeating the stop at the time of signal ON and the oscillation at the time of signal OFF by a plurality of times within one deaeration time,
A deaeration device comprising: In the degassing method of degassing by irradiating the liquid (2) in the cleaning tank (1) with ultrasonic waves by the ultrasonic oscillator (10) and the ultrasonic vibrator (4),
The microcomputer (11) of the ultrasonic oscillator (10) forms a frequency continuously modulated in a predetermined frequency bandwidth by a program based on the oscillation frequency of the ultrasonic wave irradiated from the ultrasonic transducer (4). A first step of outputting each of an ON / OFF signal (B) for repeatedly oscillating / stopping the ultrasonic wave from the ultrasonic transducer (4) together with a 0/1 signal (A) that can be generated;
The DDS (12) of the ultrasonic oscillator (10) receives the 0/1 signal (A) of the microcomputer (11) and generates a signal waveform (C) for driving the ultrasonic transducer (4). The second step;
The drive IC (13) of the ultrasonic oscillator (10) inputs the ON / OFF signal (B) of the microcomputer (11) and the signal waveform (C) of the DDS (12), and the signal waveform (C). A third step of outputting a drive signal (D) for processing the signal according to the ON / OFF signal (B);
The output stage (14) of the ultrasonic oscillator (10) receives the drive signal (D) of the drive IC (13), applies switching power (E) to the ultrasonic transducer (4), and turns on. The ultrasonic wave is intermittently emitted by repeating a signal ON stop and a signal OFF oscillation by the signal waveform (C) according to the / OFF signal (B) multiple times within one deaeration time. 4 steps,
A deaeration method characterized by comprising:

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