Radio wave radiation device

Abstract

The present invention provides a radio wave radiation device capable of increasing the possibility that a radiation target reaches a target state and improving the energy efficiency of radio waves. A radio wave radiation device (1) comprises: a signal generation unit (2) that generates a high-frequency signal; a power amplification unit (41) that amplifies the high-frequency signal; a radio wave radiation unit (51) that enables radiation of radio waves into a chamber accommodating a radiation target on the basis of the high-frequency signal amplified by the power amplification unit (41); a traveling wave power measurement unit (151) that measures the power of a traveling wave; a reflected wave power measurement unit (161) that measures the power of a reflected wave; and a control unit (71) that executes first control for controlling the power amplification unit (41) so that the power of the traveling wave is equal to or greater than a first power value for causing the radiation target to change to a target state, and switches from the first control to second control for controlling the power amplification unit (41) so that the power of the traveling wave becomes equal to or greater than a second power value that is greater than the first power value when it is determined, on the basis of the power of the reflected wave, that the radiation target has changed to the target state.

Description

Radio wave emitting device

[0001] The present disclosure relates to radio wave emitting devices.

[0002] Patent Document 1 discloses an RF energy radiating device. In the RF energy radiating device disclosed in Patent Document 1, a control unit controls an oscillator and a power amplifier according to reflected wave power detected by a return detector from a radiating element to set the operating mode to a first control mode or a second control mode. In the first control mode, the oscillator oscillates a pulsed RF signal having a first pulse width and a first pulse period. In the first control mode, a protection circuit does not cut off forward wave power. In the second control mode, the oscillator oscillates a pulsed RF signal having a second pulse width different from the first pulse width and a second pulse period different from the first pulse period. Alternatively, the oscillator oscillates the RF signal continuously. In the second control mode, a protection circuit cuts off forward wave power when the reflected wave power exceeds a predetermined threshold.

[0003] International Publication No. 2023 / 026947

[0004] The RF energy radiating device disclosed in Patent Document 1 is used to bring an object to a target state, for example, a plasma processing device (such as a semiconductor or electronic device manufacturing device) or a laser processing machine (such as a CO ２ It can be used to convert a working gas into a plasma state, i.e., to generate plasma, in a laser processing machine, etc. Generally, to generate plasma, the working gas is irradiated with microwaves to ignite the plasma. To successfully ignite the plasma, it is important to control the magnitude of the electric field strength, but the pulse control required for this (control of the pulse period, pulse width, and power difference between the minimum and maximum pulse values) is relatively difficult.

[0005] In the first control mode of the RF energy radiating device disclosed in Patent Document 1, the protection circuit does not block the forward power, and therefore, in the pulse width control of the first control mode, the pulse time is set so that when the forward power is totally reflected, the reflected power falls within the tolerance range of the RF power element. In this manner, in pulse control that mainly protects the device, the average value of the forward power is set as the target power, so there is a time when the forward power falls below the target power (for example, 50% of the total radiation time), which is one of the factors that reduces the probability of plasma ignition.

[0006] On the other hand, in the second control mode of the RF energy radiating device disclosed in Patent Document 1, a higher forward power can be set than in the first control mode, but a protection circuit cuts off the forward power when the reflected power exceeds a predetermined threshold. However, if the reflected power exceeds a predetermined threshold before plasma ignition, the forward power is cut off, which may result in a missed opportunity for plasma ignition. In particular, when using multiple power feeds or combining multiple power amplifiers with a power combiner, the reflected power may concentrate on one power amplifier, or the reflected power may concentrate on one power amplifier due to the power combiner's unequal distribution of the reflected power, which may cause the RF energy radiating device to frequently stop operating.

[0007] The present disclosure provides a radio wave emitting device that can improve the possibility that an object to be radiated will reach a target state and further improve the energy efficiency of radio waves.

[0008] A radio wave emission device according to one aspect of the present disclosure includes a signal generating unit that generates a high-frequency signal, a power amplifier unit that amplifies the high-frequency signal, a radio wave emission unit that enables radio wave emission into a chamber that contains a radiation target based on the high-frequency signal amplified by the power amplifier unit, a forward wave power measuring unit that measures the power of a forward wave that is the high-frequency signal amplified by the power amplifier unit, a reflected wave power measuring unit that measures the power of a reflected wave that flows back from the radio wave emission unit, and a control unit that controls the power amplifier unit based on the power of the forward wave measured by the forward wave power measuring unit and the power of the reflected wave measured by the reflected wave power measuring unit, wherein the control unit is configured to execute first control that controls the power amplifier unit so that the power of the forward wave is equal to or greater than a first power value for causing the radiation target to change to a target state, and when it is determined based on the power of the reflected wave that a change to the target state of the radiation target has occurred, switch from the first control to second control that controls the power amplifier unit so that the power of the forward wave is equal to or greater than a second power value that is greater than the first power value.

[0009] Aspects of the present disclosure can improve the likelihood that the radiated object will reach the target state, and further improve the energy efficiency of the radio waves.

[0010] Schematic diagram of a radio wave emitting system including a radio wave emitting device according to a first embodiment. Schematic circuit diagram of the radio wave emitting device according to the first embodiment. Flowchart of an example of operation of the radio wave emitting device according to the first embodiment. Graph of an example of time variation of power of reflected waves in the radio wave emitting device according to the first embodiment. Flowchart of an example of operation of the radio wave emitting device according to the second embodiment. Schematic diagram of a radio wave emitting system including a radio wave emitting device according to a third embodiment. Schematic circuit diagram of a first example of a first unit of the radio wave emitting device according to the third embodiment. Schematic circuit diagram of a second example of the first unit of the radio wave emitting device according to the third embodiment. Schematic circuit diagram of a second unit of the radio wave emitting device according to the third embodiment. Schematic circuit diagram of a first example of the first unit of such radio wave emitting device; Schematic circuit diagram of a second example of the first unit of the radio wave emitting device according to the fourth embodiment; Schematic circuit diagram of a first example of the first unit of the radio wave emitting device according to the fifth embodiment; Schematic circuit diagram of a second example of the first unit of the radio wave emitting device according to the fifth embodiment; Schematic circuit diagram of a third example of the first unit of the radio wave emitting device according to the fifth embodiment; Schematic circuit diagram of a fourth example of the first unit of the radio wave emitting device according to the fifth embodiment; Schematic circuit diagram of a second unit of the radio wave emitting device according to the fifth embodiment; Schematic circuit diagram of a first example of the first unit of the radio wave emitting device according to the sixth embodiment;

[0011] [1. Embodiments] Hereinafter, embodiments of the present disclosure will be described, with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following content (e.g., the shape, dimensions, and arrangement of each component). Positional relationships, such as up, down, left, and right, are based on the positional relationships shown in the drawings unless otherwise specified. Each figure described in the following embodiments is a schematic diagram, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0012] In the following description, when it is necessary to distinguish between multiple components, prefixes such as "first" and "second" are added to the names of the components. However, when the components can be distinguished from each other by the symbols attached to them, the prefixes such as "first" and "second" may be omitted in consideration of readability of the text.

[0013] In the following description, when it is necessary to distinguish between multiple components, suffixes such as "-1" and "-2" are added to the symbols of the components. However, when it is not necessary to distinguish between multiple components, the suffixes "-1" and "-2" may be omitted to improve readability.

[0014] 1 is a schematic diagram of a radio wave emission system 100 according to this embodiment. The radio wave emission system 100 includes a radio wave emission device 1, an operation unit 110, a control unit 120, an antenna 130, and a chamber 140. The radio wave emission device 1, the operation unit 110, the control unit 120, the antenna 130, and the chamber 140 are housed in the same housing.

[0015] FIG. 2 is a schematic circuit diagram of the radio wave emitting device 1 according to this embodiment.

[0016] The radio wave emission device 1 includes a signal generating unit 2, a power adjusting unit 31, a power amplifying unit 41, a radio wave emission unit 51, a communication unit 61, and a control unit 71. The radio wave emission device 1 further includes a non-reciprocal circuit 101, a terminator 111, couplers 1211 and 1212, a detection circuit 131, and temperature sensors 1411 and 1412.

[0017] The signal generating unit 2 generates, for example, a high-frequency signal for generating radio waves to be radiated to an object of radiation. The frequency of the high-frequency signal is set appropriately depending on the application of the radio wave radiation system 100. Applications of the radio wave radiation system 100 include consumer applications, industrial applications, medical applications, scientific applications, and the like. When the radio wave radiation system 100 is used for consumer applications, particularly in heaters such as microwave ovens, the frequency of the high-frequency signal may be, for example, 1 MHz to 10 GHz. By radiating radio waves to a dielectric using a high-frequency signal of such a frequency, dielectric loss occurs inside the dielectric, and heat is generated in the dielectric. This allows the dielectric to be heated.

[0018] The signal generating unit 2 includes an oscillation circuit 21, a power adjusting unit 22, and an amplifying unit 23. The signal generating unit 2 may be configured, for example, with an FPGA (Field-Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like.

[0019] The oscillator circuit 21 generates a reference high-frequency signal. For example, the oscillator circuit 21 converts a commercial AC voltage into a DC voltage and generates the reference high-frequency signal by voltage control using a semiconductor supplied with the DC voltage. The oscillator circuit 21 may also be equipped with a frequency synthesizer that generates a reference clock using a quartz oscillator or a ceramic oscillator, thereby generating the reference high-frequency signal.

[0020] The power adjustment unit 22 adjusts the power of the high-frequency signal generated by the signal generation unit 2. The power adjustment unit 22 includes a pulse control unit. The pulse control unit is used, for example, to convert the high-frequency signal from the oscillation circuit 21 into a PWM-format high-frequency signal. The power adjustment unit 22 includes, for example, a digital attenuator or analog attenuator that controls the amount of attenuation in synchronization with the PWM signal, or a variable amplifier.

[0021] The amplifier 23 amplifies the high frequency signal from the power adjustment unit 22 to a desired value. The amplifier 23 may be, for example, a well-known amplifier.

[0022] The power adjustment unit 31 adjusts the power of the high frequency signal and includes, for example, a variable amplifier 311 and a fixed amplifier 312.

[0023] The power amplifier 41 is a power amplifier that amplifies the high-frequency signal adjusted by the power adjustment unit 31. The power amplifier 41 may have one or more amplifiers. At least one of the one or more amplifiers may include a transistor. The transistor may be, for example, a field-effect transistor. The transistor may be, for example, a normally-on type. An amplifier including a transistor may be a common-source circuit in which the source terminal of the transistor is grounded, and such an amplifier outputs an amplified high-frequency signal from the drain terminal in response to a high-frequency signal input to the gate terminal of the transistor.

[0024] In this embodiment, the power amplifier 41 includes a plurality of amplifiers 411, 412, and 413 connected in series to form a multistage amplifier. The multistage amplifier allows a high-frequency signal to be amplified multiple times. For example, the driver stage (input stage) amplifiers 411 and 412 may amplify 0.1 mW to 10 W, and the final stage (output stage) amplifier 413 may amplify 10 W to 250 W. The multistage amplifier allows heat generation locations to be dispersed, reducing heat density and enabling heat dissipation with a simple cooling structure. Thus, in this embodiment, the power amplifier 41 forms a high-power amplifier (HPA).

[0025] The radio wave emitting unit 51 enables radio wave emission into the chamber 140 that accommodates the emission target, based on the high frequency signal amplified by the power amplifier 41. The radio wave emitting unit 51 may be, for example, an antenna terminal to which an antenna cable connected to an antenna that emits radio waves can be connected, or a coaxial connector to which a coaxial cable can be connected.

[0026] The communication unit 61 has one or more communication terminals 611, 612 connectable to a communication cable. The communication unit 61 enables communication with an external device using a communication signal. The communication signal includes control information related to control of the radio wave emission device 1. The control information may include, for example, instructions for starting or stopping radio wave emission, the frequency of the radio wave, the output power level of the radio wave, and the phase of the radio wave. The communication signal is, for example, a serial signal. In this embodiment, the communication terminals 611, 612 include a first communication terminal 611 and a second communication terminal 612 that have different communication standards. In particular, in this embodiment, the first communication terminal 611 and the second communication terminal 612 have different communication distances. The first communication terminal 611 corresponds to, for example, UART (Universal Asynchronous Receiver / Transmitter) or SPI (Serial Peripheral Interface). The second communication terminal 612 is compatible with a serial communication standard such as RS485. Because RS485 is more resistant to noise than UART, the second communication terminal 612 enables communication over longer distances than the first communication terminal 611. The communication unit 61 further includes a transceiver 613. The transceiver 613 is connected between the second communication terminal 612 and the control unit 71. The transceiver 613 converts the communication standard between the second communication terminal 612 and the control unit 71, for example. For example, the transceiver 613 converts between UART and RS485.

[0027] The non-reciprocal circuit 101 is located between the power amplifier 41 and the radio wave emitting unit 51. The non-reciprocal circuit 101 separates a traveling wave from a reflected wave. In this embodiment, the non-reciprocal circuit 101 transmits the traveling wave to the radio wave emitting unit 51. The non-reciprocal circuit 101 transmits the reflected wave to the terminator 111. The non-reciprocal circuit 101 is, for example, a circulator. In this embodiment, the traveling wave is a high-frequency signal amplified by the power amplifier 41. In other words, the traveling wave is a high-frequency signal supplied to the radio wave emitting unit 51. In this embodiment, the reflected wave is a signal flowing backward from the radio wave emitting unit 51.

[0028] The terminator 111 includes a termination resistor, and the reflected wave separated by the non-reciprocal circuit 101 is consumed as heat by the terminator 111.

[0029] The coupler 1211 detects the traveling wave and is located between the power amplifier 41 and the non-reciprocal circuit 101. The coupler 1211 is, for example, a directional coupler.

[0030] The coupler 1212 detects the reflected wave and is located between the non-reciprocal circuit 101 and the terminator 111. The coupler 1212 is, for example, a directional coupler.

[0031] The detection circuit 131 measures the power of the forward wave and the power of the reflected wave. More specifically, the detection circuit 131, together with the coupler 1211, constitutes a forward wave power measurement unit 151 that measures the power of the forward wave, and together with the coupler 1212, constitutes a reflected wave power measurement unit 161 that measures the power of the reflected wave. The power of the forward wave and the reflected wave are measured. In this embodiment, the detection circuit 131 receives a portion of the forward wave from the coupler 1211 and outputs a forward wave power measurement signal indicating the power of the forward wave to the control unit 71. The detection circuit 131 receives a portion of the reflected wave from the coupler 1212 and outputs a reflected wave power measurement signal indicating the power of the reflected wave to the control unit 71.

[0032] The temperature sensor 1411 directly or indirectly measures the temperature of the power amplifier 41. The temperature sensor 1411 outputs a first temperature measurement signal indicating the temperature of the power amplifier 41 to the control unit 71.

[0033] The temperature sensor 1412 directly or indirectly measures the temperature of the terminator 111. The temperature sensor 1412 outputs a second temperature measurement signal indicating the temperature of the terminator 111 to the control unit 71.

[0034] The control unit 71 controls the signal generating unit 2 and the power amplifying unit 41 based on the power of the forward wave measured by the forward wave power measuring unit 151 and the power of the reflected wave measured by the reflected wave power measuring unit 161.

[0035] In this embodiment, the control unit 71 is configured to be able to perform a first control and a second control. In the first control, the control unit 71 controls the power amplifier 41 so that the power of the traveling wave is equal to or greater than a first power value. In the second control, the control unit 71 controls the power amplifier 41 so that the power of the traveling wave is equal to or greater than a second power value that is greater than the first power value. The first power value is a power value for causing the radiation target to change to a target state. In other words, the first power value is a power value that can cause the radiation target to change to the target state. The second power value is a power value for maintaining the radiation target in the target state. For example, the first power value may be equal to or greater than 60% and less than 100% of the second power value. The second power value is appropriately set based on the radiation target. The second power value may be, for example, a power value predetermined for the radio wave emission device 1, such as a maximum or rated power value, and examples include 250 W, 500 W, and 1000 W.

[0036] The control unit 71 is configured to control the power of the forward wave in accordance with the power of the reflected wave during the first control. The control of the power of the forward wave may be set to occur within the minimum control cycle of the control unit 71. This improves responsiveness. In particular, the control unit 71 sets the power of the forward wave to a second power value when the first control starts, and controls the power amplifier 41 to reduce the power of the forward wave from the second power value when the power of the reflected wave exceeds a threshold value so that the power does not fall below the first power value. This improves the energy efficiency of the radio wave. Even when the power of the reflected wave is high, the power of the forward wave is maintained at the first power value, i.e., the power value required to cause the radiation target to change to the target state. This improves the likelihood that the radiation target will reach the target state.

[0037] The control unit 71 executes the first control to start irradiating the radiation object with radio waves, and when the radiation object changes to the target state, switches from the first control to the second control.

[0038] The control unit 71 determines whether a change to the target state of the radiation target has occurred based on the power of the reflected wave. In this embodiment, the control unit 71 determines that a change to the target state of the radiation target has occurred when the rate of decrease in the power of the reflected wave within a predetermined period is equal to or greater than a predetermined value. This enables improved accuracy in determining that a change to the target state of the radiation target has occurred, thereby increasing the likelihood that the radiation target will reach the target state. As an example, if the change to the target state of the radiation target is plasma ignition, the predetermined period may be equal to or greater than 1 ms and equal to or less than 5 s, and the predetermined value may be 10%. This enables improved accuracy in determining that a change to the target state of the radiation target has occurred, thereby increasing the likelihood that the radiation target will reach the target state.

[0039] When switching from the first control to the second control, the control unit 71 controls the power amplifier 41 so that the power of the traveling wave becomes equal to or greater than the second power value within a specified period of time after determining that a change to the target state of the radiation target has occurred. This improves the likelihood that the radiation target will reach the target state. In other words, the control unit 71 immediately switches from the first control to the second control and controls the power amplifier 41 so that the power of the traveling wave becomes equal to or greater than the first power value. This improves the likelihood that the target state of the radiation target will be maintained. As an example, if the change to the target state of the radiation target is plasma ignition, the specified period may be 1 ms or more and 40 ms or less. This improves the likelihood that the radiation target will reach the target state.

[0040] Next, the operation of the radio wave emitting device 1, that is, the operation of the control unit 71, will be briefly described with reference to FIGS.

[0041] Fig. 3 is a flowchart of an example of the operation (operation of the control unit 71) of the radio wave emission device 1. Fig. 4 is a graph showing the change over time in the power of the forward wave and the power of the reflected wave in the radio wave emission device 1. In Fig. 4, F1 indicates the power of the forward wave, and F2 indicates the power of the reflected wave.

[0042] The control unit 71 executes the first control (S1) when starting to irradiate the target object with radio waves. Referring to Fig. 4 , the control unit 71 first controls the power amplifier 41 so that the power of the forward wave becomes the second power value Pf2. At this time, the power of the reflected wave exceeds the threshold value Pr1, so the control unit 71 reduces the power of the forward wave from the second power value Pf2 within a range that does not fall below the first power value Pf1. In Fig. 4 , the power of the reflected wave becomes equal to or less than the threshold value Pr1 at time t1, and thereafter, the power of the reflected wave remains near the threshold value Pr1 until time t2.

[0043] The control unit 71 determines whether a change to the target state of the radiation target has occurred based on the power of the reflected wave (S2). Referring to Fig. 4, the power of the reflected wave sharply decreases from Pr1 to Pr2 from time t2 to time t3. For example, if the rate of decrease in the power of the reflected wave (= Pr1 - Pr2) / Pr1 is 10% or more and the time difference (predetermined time) between times t2 and t3 is 1 ms or more and 5 s or less, it is determined that a change to the target state of the radiation target has occurred.

[0044] When the control unit 71 determines that a change to the target state of the radiation target has occurred based on the power of the reflected wave (S2; YES), it switches from the first control to the second control (S3). Referring to Fig. 4, the control unit 71 controls the power amplifier 41 so that the power of the forward wave becomes the second power value Pf2. In Fig. 4, the power of the forward wave becomes the second power value Pf2 at time t4. The time difference between time t3 and time t4 corresponds to a specified period, and is preferably 1 ms or more and 40 ms or less.

[0045] Thereafter, when the termination condition is satisfied (S4: YES), the control unit 71 stops driving the signal generating unit 2 and terminates the output of the high-frequency signal (S5). The termination condition may be, for example, the passage of time or the presence or absence of an operation by the user.

[0046] Such a control unit 71 enables adaptive control to the minimum traveling wave power that allows plasma ignition at the initial stage, thereby preventing an unnecessary drop in electric field strength (i.e., a drop in the energy of the radio waves radiated to the target object). In addition, the control unit 71 instantaneously increases the traveling wave power at the ignition timing, thereby maintaining the plasma state and improving the probability of plasma ignition.

[0047] The control unit 71 executes a protection operation as necessary. For example, when the control unit 71 determines that an abnormality has occurred in the radio wave emission device 1 based on the reflected wave power measurement signal from the detection circuit 131, the first temperature measurement signal from the temperature sensor 1411, and the second temperature measurement signal from the temperature sensor 1412, the control unit 71 can stop or reduce the emission of radio waves.

[0048] The control unit 71 may be configured, for example, by a microcontroller having one or more microprocessors and a memory. A part of the control unit 71 may be configured by adding, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0049] 1 again, the operation unit 110 receives information from the user and presents the information to the user. The operation unit 110 constitutes, for example, a graphical user interface (GUI).

[0050] The control unit 120 transmits a communication signal to the radio wave emitting device 1 in response to an input to the operation unit 110. The control unit 120 transmits a communication signal indicating a target value for the output power (power of traveling waves) of the radio wave emitting device 1 to the radio wave emitting device 1. The control unit 120 is, for example, an application controller unit (ACU).

[0051] The antenna 130 is connected to the radio wave emitting section 51 of the radio wave emitting device 1. The antenna 130 emits radio waves based on the amplified high frequency signal from the radio wave emitting section 51.

[0052] The chamber 140 accommodates an object to be irradiated. An antenna 130 is disposed in the chamber 140, enabling radio waves to be irradiated to the object to be irradiated in the chamber 140. The object to be irradiated may be a working gas or a heating object such as a food material to be heated. The working gas is used, for example, in plasma processing or dry etching. Examples of the working gas used in plasma processing include inert gas, H ２ , O ２ , N ２ Examples of the inert gas include argon (Ar), helium (He), xenon (Xe), and neon (Ne). Examples of the working gas used in dry etching include fluorine-based gas (CF ４ , S.F. ６ ), chlorine-based gas (Cl ２ , BCl ３ HCl) and the like.

[0053] In the radio wave emission system 100, the radio wave emission device 1 and the control unit 120 are housed in the same housing. A communication path 150 is formed between the radio wave emission device 1 and the control unit 120. The communication path 150 is configured using the first communication terminal 611 of the communication unit 61 of the radio wave emission device 1. The communication path 150 is set so that the wiring length is 50 cm or less.

[0054] [1.1.2 Effects, etc.] The radio wave emission device 1 described above includes a signal generating unit 2 that generates a high-frequency signal, a power amplifier 41 that amplifies the high-frequency signal, a radio wave emission unit 51 that enables radio wave emission into a chamber that accommodates an emission target based on the high-frequency signal amplified by the power amplifier 41, a forward wave power measuring unit 151 that measures the power of a forward wave that is the high-frequency signal amplified by the power amplifier 41, a reflected wave power measuring unit 161 that measures the power of a reflected wave that flows back from the radio wave emission unit 51, and a power measuring unit 162 that measures the power of the forward wave measured by the forward wave power measuring unit 151 and the power of the reflected wave measured by the forward wave power measuring unit 151. and a control unit 71 that controls the signal generating unit 2 and the power amplifying unit 41 based on the power of the reflected wave measured by the control unit 71. The control unit 71 is configured to execute a first control that controls the power amplifying unit 41 so that the power of the forward wave is equal to or greater than a first power value for causing the radiation target to change to a target state, and when it is determined based on the power of the reflected wave that a change to the target state of the radiation target has occurred, to switch from the first control to a second control that controls the power amplifying unit 41 so that the power of the forward wave is equal to or greater than a second power value that is greater than the first power value. This configuration can improve the possibility that the radiation target will reach the target state, and further improve the energy efficiency of the radio wave.

[0055] In the radio wave emission device 1, the first power value is equal to or greater than 60% and less than 100% of the second power value. This configuration can improve the possibility that the radiation target will reach the target state, and further improve the energy efficiency of the radio waves.

[0056] In the radio wave emission device 1, the control unit 71 determines that a change to the target state of the emission object has occurred when the rate of decrease in the power of the reflected wave within a predetermined period is equal to or greater than a predetermined value. This configuration improves the accuracy of determining that a change to the target state of the emission object has occurred, thereby increasing the possibility that the emission object will reach the target state.

[0057] In the radio wave emission device 1, the predetermined period is 1 ms or more and 5 seconds or less. This configuration improves the accuracy of determining whether the emission target has changed to the target state, thereby increasing the possibility that the emission target will reach the target state.

[0058] The predetermined value is 10% in the radio wave emitting device 1. This configuration improves the accuracy of determining whether the emission target has changed to the target state, thereby increasing the possibility that the emission target will reach the target state.

[0059] In the radio wave emission device 1, when switching from the first control to the second control, the control unit 71 controls the power amplifier 41 so that the power of the traveling wave becomes equal to or greater than the second power value within a specified period after determining that the emission target has changed to the target state. This configuration can improve the possibility that the emission target will reach the target state.

[0060] In the radio wave emitting device 1, the specified period is 1 ms or more and 40 ms or less. This configuration can improve the possibility that the object to be radiated will reach the target state.

[0061] In the radio wave emitting device 1, the control unit 71 is configured to control the power of the forward wave in accordance with the power of the reflected wave in the first control. This configuration can improve the energy efficiency of the radio wave.

[0062] In the radio wave emission device 1, the control unit 71 sets the power of the forward wave to a second power value at the start of the first control, and controls the power amplifier 41 to reduce the power of the forward wave from the second power value so as not to become less than the first power value when the power of the reflected wave exceeds a threshold. This configuration can improve the energy efficiency of the radio wave.

[0063] [1.2 Second Embodiment] [1.2.1 Configuration] The configuration of the radio wave emission device according to this embodiment is the same as that of the radio wave emission device 1 according to the first embodiment, and therefore, the drawings and symbols of the radio wave emission device 1 according to the first embodiment will be used as necessary.

[0064] In this embodiment, the control unit 71 may change the radio frequency signal from continuous wave to pulse wave when the power of the forward wave becomes equal to or greater than a second power value after determining that the target state of the radiation object has changed based on the power of the reflected wave. This reduces the energy of the radio waves radiated into the chamber 140, thereby reducing the temperature rise inside the chamber 140. For example, the control unit 71 controls the signal generating unit 2 to change the radio frequency signal from continuous wave to pulse wave. In this case, the control unit 71 may control the attenuation rate of the pulse wave radio frequency signal in synchronization with the pulse period of the pulse wave radio frequency signal. This allows for improved energy efficiency.

[0065] Next, the operation of the radio wave emission device 1, i.e., the operation of the control unit 71, will be briefly described with reference to Fig. 5. Fig. 5 is a flowchart of an example of the operation of the radio wave emission device 1 (operation of the control unit 71). Steps S11 to S13, S16, and S17 in Fig. 5 are the same as steps S1 to S5 in Fig. 3.

[0066] When the control unit 71 determines that a change to the target state of the radiation target has occurred based on the power of the reflected wave (S12; YES), it switches from the first control to the second control (S13) and determines whether the power of the forward wave has become equal to or greater than the second power value (S14).

[0067] When the control unit 71 determines that the power of the traveling wave has reached the second power value or more (S14: YES), it controls the signal generating unit 2 so that the high-frequency signal changes from a continuous wave to a pulse wave (S15).

[0068] Thereafter, the control unit 71 determines whether or not the termination condition is satisfied (S16).

[0069] [1.2.2 Effects, etc.] In the radio wave emission device 1 described above, the control unit 71 is configured to change the high-frequency signal from a continuous wave to a pulse wave when the power of the forward wave becomes equal to or greater than a second power value after determining that a change to the target state of the emission object has occurred based on the power of the reflected wave. This configuration can reduce the energy of the radio waves emitted into the chamber 140 and reduce the temperature rise inside the chamber 140.

[0070] In the radio wave emission device 1, the control unit 71 is configured to control the attenuation rate of the pulsed high frequency signal in synchronization with the pulse period of the pulsed high frequency signal. This configuration makes it possible to improve energy efficiency.

[0071] 6 is a schematic diagram of a radio wave emission system 200 according to this embodiment. The radio wave emission system 200 includes a radio wave emission device 1A, a control device 210, and a combiner 220.

[0072] The radio wave emission device 1A is used to emit radio waves of a desired output power to an emission target. The radio wave emission device 1A includes a first unit 11 and one or more second units 12. FIG. 6 illustrates seven second units 12. In the radio wave emission system 200, the first unit 11 and the second unit 12 have the function of enabling radio wave emission. As an example, each of the first unit 11 and the second unit 12 can emit radio waves with a maximum output power of 250 W. In the radio wave emission device 1A, the maximum output power of radio waves that can be emitted from the radio wave emission device 1A can be changed by changing the number of second units 12. If there are seven second units 12, the maximum output power of the radio waves is 250 W × (1 + 7) = 2 kW. If there is only one second unit 12, the maximum output power of the radio waves is 250 W × (1 + 1) = 500 W. In the radio wave emitting device 1A, the first unit 11 is a master-type radio wave emitting device that can emit radio waves independently, and the second unit 12 is a slave-type radio wave emitting device that cannot emit radio waves without the presence of a master-type radio wave emitting device. When there is no need to distinguish between the first unit 11 and the second unit 12, they may be simply referred to as "units."

[0073] First, a description will be given of the first unit 11. Fig. 7 is a schematic circuit diagram of a first example of the first unit 11 (hereinafter referred to as first unit 11A1).

[0074] 7, the first unit 11A1 includes a signal generating unit 2A, a power adjusting unit 31, a power amplifying unit 41, a radio wave emitting unit 51, a communication unit 61A, a control unit 71, an output unit 81, and an input unit 91. The first unit 11A1 further includes a non-reciprocal circuit 101, a terminator 111, couplers 1211 and 1212, a detection circuit 131, and temperature sensors 1411 and 1412. Note that a description of the components of the first unit 11A1 that are the same as those of the radio wave emitting device 1 will be omitted.

[0075] The signal generating unit 2A generates a plurality of high frequency signals having the same frequency band and phase. In this embodiment, the signal generating unit 2A is configured to be able to generate up to eight high frequency signals.

[0076] The signal generating unit 2A includes an oscillation circuit 21 , a power adjusting unit 22 , an amplifying unit 23 , a distributor 24 , and a signal adjusting unit 25 .

[0077] The divider 24 outputs multiple high-frequency signals by equally dividing the high-frequency signal from the oscillation circuit 21. That is, the frequency bands of the multiple high-frequency signals are each equal to the frequency band of the high-frequency signal from the oscillation circuit 21. The multiple high-frequency signals may have the same frequency band and phase. In this embodiment, the divider 24 is configured to be able to output a maximum of eight high-frequency signals. One of the eight high-frequency signals is used by the first unit 11A1, and the remaining seven are used by the second units 12. The number of high-frequency signals is set according to the number of second units 12.

[0078] The signal conditioning unit 25 is inserted between the power conditioning unit 22 and the amplifier unit 23. The signal conditioning unit 25 may be a conventionally known attenuator or amplifier.

[0079] The communication unit 61A differs from the communication unit 61 mainly in that it includes a synchronization terminal 614. The synchronization terminal 614 is a terminal for a synchronization signal. The synchronization signal is a signal for synchronization between the first unit 11 and one or more second units 12. The synchronization signal is, for example, a single pulse or a pulse train rather than a serial signal. The first unit 11 may perform operations based on the synchronization signal for synchronization with one or more second units 12.

[0080] In this embodiment, the control unit 71 may control the signal adjustment unit 25 of the signal generation unit 2A. In the radio wave emission device 1A, the maximum output of radio waves can be adjusted depending on the number of second units 12. Here, the number of high-frequency signals is determined according to the number of second units 12. For the same power of the high-frequency signals input to the divider 24, the power of each high-frequency signal output from the divider 24 decreases as the number of divided high-frequency signals (particularly the number of second high-frequency signals) increases. Therefore, the control unit 71 adjusts the power of the high-frequency signals input to the divider 24 based on the number of multiple high-frequency signals output from the divider 24 so that each of the multiple high-frequency signals has a predetermined power. The predetermined power is, for example, 0.1 mW. Assuming there is no power loss in the divider 24, if the number of high-frequency signals output from the divider 24 is two, the power of the high-frequency signals input to the divider 24 is set to 0.1 mW × (1 + 1) = 0.2 mW. If the number of high frequency signals output from the divider 24 is 7, the power of the high frequency signals input to the divider 24 is set to 0.1 mW×(1+7)=0.8 mW.

[0081] The control unit 71 performs operations based on the synchronization signal. Specifically, the control unit 71 controls the emission of radio waves from the radio wave emission unit 51 based on the synchronization signal. In the present embodiment, the control unit 71 outputs the synchronization signal from the synchronization terminal 614. Preferably, the control unit 71 may output the synchronization signal from the synchronization terminal 614 at regular intervals or upon receiving a communication signal. This makes it possible to maintain synchronization between the first unit 11 and one or more second units 12 even after the first unit 11 and one or more second units 12 have started operating in synchronization with each other. In particular, it is possible to maintain synchronization between the first unit 11 and one or more second units 12 even if the operation of the first unit 11 and / or one or more second units 12 is changed.

[0082] In this embodiment, the detection circuit 131 and the temperature sensors 1411 and 1412 are used as a first abnormality detection unit that detects a first index value of an abnormality in the first unit 11. That is, the first abnormality detection unit may include the detection circuit 131 that measures the power of a reflected wave of the first radio wave as the first index value. The first abnormality detection unit may include temperature sensors 1411 and 1412 that measure the temperature of the first unit 11 as the first index value. The temperature sensor 1412 may measure the temperature of the terminator 111. When the first index value detected by the first abnormality detection unit exceeds a first threshold, the control unit 71 stops or reduces radio wave emission. Note that the first threshold when the first index value is the power of the reflected wave and the first threshold when the first index value is the temperature may be set appropriately taking into account the abnormal state of the first unit 11.

[0083] The output unit 81 outputs a high-frequency signal from the first unit 11A1 to the outside. The output unit 81 has a plurality of output terminals 811. Each output terminal 811 can be connected to a coaxial cable. The output terminals 811 of the output unit 81 are connected to the plurality of output terminals of the distributor 24, respectively.

[0084] In this embodiment, seven second units 12 can be connected to seven of the eight output terminals 811 via coaxial cables.

[0085] The input unit 91 can be connected to a coaxial cable. The input unit 91 is connected to one of the multiple output terminals 811 of the output unit 81 via the coaxial cable C. Therefore, a high-frequency signal is input to the input unit 91. The input unit 91 is connected to the power adjustment unit 31, and inputs the received high-frequency signal to the power adjustment unit 31.

[0086] The first unit 11A1 can output a high-frequency signal to the second unit 12. In the first unit 11A1, the high-frequency signal is input from the signal generating unit 2A to the power adjusting unit 31 via the coaxial cable C, and radio waves based on the high-frequency signal can be emitted from the radio wave emitting unit 51.

[0087] FIG. 8 is a schematic circuit diagram of a second example of the first unit 11 (hereinafter referred to as first unit 11A2).

[0088] 8, the first unit 11A2 includes a signal generating unit 2A, a power adjusting unit 31, a power amplifying unit 41, a radio wave emitting unit 51, a communication unit 61A, a control unit 71, and an output unit 81A. The first unit 11A2 further includes a non-reciprocal circuit 101, a terminator 111, couplers 1211 and 1212, a detection circuit 131, and temperature sensors 1411 and 1412. Note that a description of the components of the first unit 11A2 that are the same as those of the radio wave emitting device 1 or the first unit 11A1 will be omitted.

[0089] In the first unit 11A2, the power adjustment unit 31 is connected to the signal generating unit 2A to receive one of the multiple high-frequency signals generated by the signal generating unit 2A. The output unit 81 is connected to the signal generating unit 2A to receive one or more of the remaining multiple high-frequency signals generated by the signal generating unit 2A. Therefore, the output unit 81 does not have an output terminal 811 for the first unit 11A1, and all of the output terminals 811 of the output unit 81 are used to output high-frequency signals to the second unit 12.

[0090] In first unit 11A2, a high-frequency signal is input from signal generating unit 2A to power adjusting unit 31 within first unit 11A2, and the high-frequency signal is input from signal generating unit 2A to output unit 81. This configuration eliminates the need for coaxial cable C for inputting the high-frequency signal from signal generating unit 2A to power adjusting unit 31, thereby reducing costs.

[0091] Next, a description will be given of the second unit 12. Fig. 9 is a schematic circuit diagram of the second unit 12 according to this embodiment.

[0092] The second unit 12 includes an adjustment unit 32, a power amplifier 42, a radio wave emitter 52, a communication unit 62A, a control unit 72, and an input unit 92. The second unit 12 further includes a non-reciprocal circuit 102, a terminator 112, couplers 1221 and 1222, a detection circuit 132, and temperature sensors 1421 and 1422.

[0093] The input unit 92 can be connected to a coaxial cable. The input unit 92 is connected to one of the output terminals 811 of the output unit 81 via the coaxial cable. Therefore, a high-frequency signal is input to the input unit 92. The input unit 92 is connected to the adjustment unit 32 and inputs the received high-frequency signal to the adjustment unit 32.

[0094] The adjustment unit 32 adjusts the phase and power of the high-frequency signal. In the present embodiment, the adjustment unit 32 includes, for example, a phase adjuster 321 and a variable attenuator 322. The phase adjuster 321 can be used to adjust the phase of the high-frequency signal from the second unit 12, for example, so that the difference between the phase (reference phase) of the high-frequency signal from the first unit 11 and the phase of the high-frequency signal from the second unit 12 becomes small.

[0095] The power amplifier 42 is a signal amplifier that amplifies the high-frequency signal adjusted by the adjustment unit 32. Similar to the power amplifier 41, the power amplifier 42 may include one or more amplifiers 421, 422, and 423. At least one of the one or more amplifiers may include a transistor. In the present embodiment, the power amplifier 42 constitutes a high power amplifier (HPA).

[0096] The radio wave emitting unit 52 is capable of emitting radio waves based on the high frequency signal amplified by the power amplifier 42. The radio wave emitting unit 52 may be, for example, an antenna terminal to which an antenna cable connected to an antenna that radiates radio waves can be connected, or a coaxial connector to which a coaxial cable can be connected.

[0097] The communication unit 62A has one or more communication terminals 621, 622 connectable to a communication cable. The communication unit 62A enables communication with an external device using a communication signal. The communication signal includes control information related to control of the second unit 12. The control information may include, for example, instructions for starting or stopping radio wave emission, the frequency of the radio wave, the output power level of the radio wave, and the phase of the radio wave. The communication signal is, for example, a serial signal. In this embodiment, the first communication terminals 621, 622 include a first communication terminal 621 and a second communication terminal 622 that have different communication standards. In this embodiment, the first communication terminal 621 and the second communication terminal 622 have different communication distances. The first communication terminal 621 corresponds to, for example, UART or SPI. The second communication terminal 622 corresponds to a serial communication standard such as RS485. The communication unit 62 further includes a transceiver 623. The transceiver 623 is connected between the second communication terminal 622 and the control unit 72. The transceiver 623 converts, for example, the communication standard between the second communication terminal 622 and the control unit 72. For example, the transceiver 623 converts between UART and RS485.

[0098] The communication unit 62A further includes a synchronization terminal 624. The synchronization terminal 624 is a terminal for a synchronization signal. In this embodiment, the synchronization terminal 624 includes an input terminal 624a, an output terminal 624b, and a buffer amplifier 624c between the input terminal 624a and the output terminal 624b. The buffer amplifier 624c is arranged so that the synchronization signal input to the input terminal 624a is output from the output terminal 624b without change. The response characteristic of the buffer amplifier 624c is, for example, several nanoseconds or less. The synchronization signal is input to the control unit 72 from the input terminal 624a and output from the output terminal 624b via the buffer amplifier 624c. The second unit 12 may perform operations based on the synchronization signal for synchronization with the first unit 11.

[0099] The non-reciprocal circuit 102, terminator 112, couplers 1221 and 1222, detection circuit 132, and temperature sensors 1421 and 1422 of the second unit 12 are similar to the non-reciprocal circuit 101, terminator 112, couplers 1211 and 1212, detection circuit 131, and temperature sensors 1411 and 1412 of the radio wave emission device 1, respectively, and therefore description thereof will be omitted. In the second unit 12, the detection circuit 132, together with the coupler 1221, constitutes a forward wave power measurement unit 152 that measures the power of a forward wave, and together with the coupler 1222, constitutes a reflected wave power measurement unit 162 that measures the power of a reflected wave.

[0100] The control unit 72 is configured to control the power amplifier 42 based on the power of the forward wave measured by the forward wave power measurement unit 152 and the power of the reflected wave measured by the reflected wave power measurement unit 162. In particular, the control unit 72 executes first control to control the power amplifier 42 so that the power of the forward wave is equal to or greater than a first power value for causing the radiation target to change to a target state, and when it determines that a change to the target state of the radiation target has occurred based on the power of the reflected wave, switches from the first control to second control to control the power amplifier 42 so that the power of the forward wave is equal to or greater than a second power value that is greater than the first power value. This operation of the control unit 72 is similar to that of the control unit 71, and therefore will not be described here.

[0101] The control unit 72 performs operations based on the synchronization signal received through the synchronization terminal 624 of the communication unit 62A. Specifically, the control unit 72 controls the emission of radio waves from the radio wave emission unit 52 based on the synchronization signal.

[0102] The control unit 72 executes a protection operation as necessary. For example, when the control unit 72 determines that an abnormality has occurred in the second unit 12 based on the reflected wave power measurement signal from the detection circuit 132, the first temperature measurement signal from the temperature sensor 1421, and the second temperature measurement signal from the temperature sensor 1422, the control unit 72 can stop or reduce the emission of radio waves.

[0103] More specifically, the detection circuit 132 and the temperature sensors 1421 and 1422 may be used as a second abnormality detection unit that detects a second index value of an abnormality in the second unit 12. That is, the second abnormality detection unit may include the detection circuit 132 that measures the power of a reflected wave of the second radio wave as the second index value. The second abnormality detection unit may include temperature sensors 1421 and 1422 that measure the temperature of the second unit 12 as the second index value. The temperature sensor 1422 may measure the temperature of the terminator 112. When the second index value detected by the second abnormality detection unit exceeds a second threshold, the control unit 72 stops or reduces radio wave emission. Note that the second threshold when the second index value is the power of the reflected wave and the second threshold when the second index value is the temperature may be set appropriately taking into account the abnormal state of the second unit 12.

[0104] The control unit 72 may be configured, for example, by a microcontroller having one or more microprocessors and a memory, or may be configured, for example, by an FPGA, an ASIC, or the like.

[0105] As described above, the radio wave emission device 1A includes the first unit 11 (first units 11A1 and 11A2) and seven second units 12. The seven second units 12 are connected to the seven output terminals 811 of the output section 81 of the first unit 11 via coaxial cables, respectively.

[0106] The radio wave emitting device 1A described above includes a first unit 11. The first unit 11 is capable of emitting radio waves. Because the first unit 11 alone can be used to perform pre-installation testing of the radio wave emitting device 1A, there is no need to use a separate radio wave emitting device other than the radio wave emitting device 1A for the pre-installation testing. This reduces implementation costs. By connecting a required number of second units 12 to the output terminal 811 of the output section 81 of the first unit 11, radio waves from the first unit 11 and the required number of second units 12 can be combined and radiated, allowing the output power to be increased as desired. The configuration (number of second units 12) of the radio wave emitting device 1A can be easily changed depending on the required output power. This reduces implementation costs.

[0107] Referring again to FIG. 6, the control device 210 includes an operation unit 211 and a control unit 212 .

[0108] The operation unit 211 receives information from the user and presents the information to the user. The operation unit 211 constitutes, for example, a graphical user interface (GUI).

[0109] The control unit 212 transmits a communication signal to the radio wave emission device 1A in response to an input to the operation unit 211. Similar to the control unit 120, the control unit 212 transmits a communication signal indicating a target value of the output power of the first unit 11 to the first unit 11, and further transmits a communication signal indicating a target value of the output power of the second unit 12 to the second unit 12.

[0110] A communication path 230 is formed between the radio wave emission device 1A and the control unit 212 of the control device 210. The communication path 230 is configured using the second communication terminal 612 of the communication unit 61 of the first unit 11 of the radio wave emission device 1A or the second communication terminal 622 of the communication unit 62 of the second unit 12. The communication path 230 is compatible with, for example, RS485, and enables stable communication even if the wiring length is 50 cm or more.

[0111] The combiner 220 is connected via a coaxial cable to the radio wave emitting section 51 of the first unit 11 and the radio wave emitting sections 52 of the seven second units 12 of the radio wave emitting device 1A. The combiner 220 combines and outputs the eight high-frequency signals input from the radio wave emitting device 1A (the high-frequency signal from the first unit 11 and the seven high-frequency signals from the second units 12). For example, in Fig. 6, the power of the eight high-frequency signals is 250 W, and the power of the combined high-frequency signal is 2 kW.

[0112] As described above, the radio wave emitting device 1A includes a plurality of units (first unit 11 and one or more second units 12) that each emit radio waves. In this embodiment, the plurality of units (first unit 11 and one or more second units 12) operate in synchronization with one another under the first control, and operate independently of one another under the second control. This will be described in further detail below.

[0113] When the control unit 71 of the first unit 11 executes control of the power amplifier 41 in the first control, it outputs a communication signal indicating the control content of the power amplifier 41 from the communication terminal 611 (612) to another control unit 72. Similarly, when the control unit 72 of the second unit 12 executes control of the power amplifier 42 in the first control, it outputs a communication signal indicating the control content of the power amplifier 42 from the communication terminal 621 (622). As described above, the control units 71 and 72 set the power of the forward wave to a second power value at the start of the first control, and when the power of the reflected wave exceeds the threshold, control the power amplifiers 41 and 42 to reduce the power of the forward wave from the second power value so that it does not become less than the first power value. Therefore, the control content of the power amplifiers 41 and 42 may include the amount of reduction in the power of the forward wave.

[0114] When the control unit 71 of the first unit 11 receives a communication signal from the control unit 72 via the communication terminal 611 (612), it controls the power amplifier 41 according to the control content of the power amplifier 42 indicated by the communication signal. When the control unit 72 of the second unit 12 receives a communication signal from another control unit 71, 72 (the control unit 71 of the first unit 11 or the control unit 72 of another second unit 12) via the communication terminal 621 (622), it controls the power amplifier 42 according to the control content of the power amplifier 41, 42 indicated by the communication signal.

[0115] In this way, in the first control, the multiple units (the first unit 11 and one or more second units 12) share the control contents.

[0116] In the first control, the control units 71 and 72 execute operations in synchronization with other control units 71 and 72 based on the synchronization signals received via the synchronization terminals 614 and 624 .

[0117] When the first unit 11 and one or more second units 12-1 to 12-7 operate in synchronization with each other, the first unit 11 and one or more second units 12-1 to 12-7 may become out of synchronization even if they start operating at the same time. This may be because the reference clocks (crystal oscillator circuits, etc.) on which the microcomputers of the first unit 11 and one or more second units 12-1 to 12-7 operate are not the same. Even if the same frequency reference clock is used, there is actually a frequency error on the order of ppm, and therefore, as time passes, the synchronization error between the first unit 11 and one or more second units 12-1 to 12-7 may increase.

[0118] In this embodiment, as described above, in the radio wave emission device 1A, the first unit 11 and one or more second units 12-1 to 12-7 operate in synchronization with each other using a synchronization signal. FIG. 10 is an explanatory diagram of the synchronization method of the radio wave emission device 1A. In FIG. 10, the second units 12-1 to 12-7 are daisy-chain connected to the first unit 11 with respect to the synchronization signal. Specifically, the synchronization terminal 614 of the first unit 11 is connected to the input terminal 624a of the synchronization terminal 624 of the second unit 12-1, and the output terminal 624b of the synchronization terminal 624 of the second unit 12-1 is connected to the input terminal 624a of the synchronization terminal 624 of the second unit 12-2. Thereafter, the output terminal 624b of the synchronization terminal 624 of the second units 12-3 to 12-6 is connected to the input terminal 624a of the synchronization terminal 624 of the second units 12-4 to 12-7 in the subsequent stage, respectively. As a result, the synchronization signal output from the synchronization terminal 614 of the first unit 11 is transmitted in sequence to the second units 12-1 to 12-7, thereby enabling the first unit 11 and one or more second units 12-1 to 12-7 to operate in synchronization with each other via the synchronization signal.

[0119] In this way, in the first control, the operation timings of the multiple units (the first unit 11 and one or more second units 12) are synchronized.

[0120] On the other hand, when each of the control units 71 and 72 determines that a change to the target state of the radiation target has occurred based on the power of the reflected wave, it switches from the first control to the second control. In this embodiment, the control units 71 and 72 switch from the first control to the second control independently of the other control units 71 and 72. In the second control, the control units 71 and 72 perform operations independently of the other control units 71 and 72. In other words, in the second control, the control units 71 and 72 may operate regardless of the synchronization signal.

[0121] In the radio wave emission device 1A of this embodiment, the response time under the first control is the minimum control period of the control units 71 and 72 plus the transmission time of the communication signal (transmission time of serial communication) and the synchronization processing time using the synchronization signal. Therefore, the responsiveness under the first control may be slower by several milliseconds to several tens of milliseconds than the responsiveness under the second control. The degree of change in responsiveness may be determined by the processing speed of the microcomputer installed in the control units 71 and 72 and the transmission speed of the serial communication.

[0122] The communication signal may be output from the control units 71 and 72 to the other control units 71 and 72 via the control unit 212 of the control device 210. In other words, the communication signal does not necessarily have to be transmitted and received directly between the units.

[0123] In the radio wave emission device 1A, the power output from each of the first unit 11 and one or more second units 12 is combined by the combiner 220 and radiated, but depending on the application, some of the power may be reflected due to impedance mismatch or the like, and this reflected power may generate a reflected wave inside each of the first unit 11 and one or more second units 12 via the combiner 220. As described above, the reflected wave is detected by the couplers 1211, 1212 and the detection circuits 131, 122, and when the reflected wave is consumed by the terminators 111, 112, it increases the temperature of the terminators 111, 112.

[0124] As described above, the detection circuit 131 and the temperature sensors 1411 and 1412 are used as a first abnormality detection unit that detects a first index value of an abnormality in the first unit 11. When the first index value detected by the first abnormality detection unit exceeds a first threshold, the control unit 71 stops or reduces radio wave emission. This makes it possible to resolve the abnormal state of the first unit 11. Furthermore, the detection circuit 132 and the temperature sensors 1421 and 1422 are used as a second abnormality detection unit that detects a second index value of an abnormality in the second unit 12. When the second index value detected by the second abnormality detection unit exceeds a second threshold, the control unit 72 stops or reduces radio wave emission. This makes it possible to resolve the abnormal state of the second unit 12.

[0125] However, if the power flowing back through the combiner 220 is not distributed equally to the first unit 11 and the one or more second units 12, or if even if the power is distributed equally, there is an error in the detection circuit of each of the first unit 11 and the one or more second units 12, or if there is an individual difference in temperature rise due to differences in the cooling conditions of each unit, then only one or some of the multiple units (the first unit 11 and the one or more second units 12) of the radio wave emission device 1A may be determined to be in an abnormal state. If the radio wave radiation of a unit determined to be in an abnormal state is stopped or reduced, the combining characteristics of the combiner 220 may change, and radio waves from units not determined to be in an abnormal state may flow into the unit determined to be in an abnormal state, and the abnormal state of the unit determined to be in an abnormal state may not be resolved even though the radio wave radiation of the unit determined to be in an abnormal state has been stopped or reduced.

[0126] Therefore, when the first index value detected by the first abnormality detection unit exceeds the first threshold, the control unit 71 may transmit a first abnormality signal through the communication unit 61A. Furthermore, when the second index value detected by the second abnormality detection unit exceeds the second threshold, the control unit 72 may transmit a second abnormality signal through the communication unit 62A.

[0127] The first abnormality signal is transmitted to one or more second units 12 (12-1 to 12-7). Then, in one or more second units 12 (12-1 to 12-7), the control unit 72 may stop or reduce radio wave radiation upon receiving the first abnormality signal. This reduces the influence of other units, making it possible to resolve the abnormal state of the first unit 11. The first abnormality signal may be transmitted directly to one or more second units 12 (12-1 to 12-7). Alternatively, the first abnormality signal may be transmitted to the control unit 212, which then transmits the first abnormality signal to one or more second units 12 (12-1 to 12-7).

[0128] The second abnormality signal is transmitted to the first unit 11 and one or more second units 12 that have not transmitted the second abnormality signal (i.e., units that have not been determined to be in an abnormal state). In the first unit 11, the control unit 71 may stop or reduce radio wave radiation upon receiving the second abnormality signal. In one or more second units 12 (12-1 to 12-7), the control unit 72 may stop or reduce radio wave radiation upon receiving the second abnormality signal. This reduces the influence of other units, thereby enabling the abnormal state of the second unit 12 to be resolved. The second abnormality signal may be transmitted directly to units that have not been determined to be in an abnormal state. Alternatively, the second abnormality signal may be transmitted to the control unit 212, which then transmits the second abnormality signal to units that have not been determined to be in an abnormal state.

[0129] Note that at least one, but not all, of the control units 72 that received the first abnormal signal may stop or reduce radio wave radiation. Also, at least one, but not all, of the control unit 71 of the first unit 11 that received the second abnormal signal and the control unit 72 of one or more second units 12 that received the second abnormal signal may stop or reduce radio wave radiation. For example, when an abnormal state is determined in one of the multiple units, which of the remaining units should stop or reduce radio wave radiation may be determined based on the configuration of the radio wave emission system 1. For example, in a radiation device that is not coupled to the radiation device determined to be in an abnormal state by a combiner or the like and is independent, it is not necessarily necessary to stop or reduce radio wave radiation.

[0130] [1.3.2 Effects, etc.] The radio wave emission device 1A described above includes a plurality of power amplifiers 41, 42, a plurality of radio wave emission units 51, 52, and a combiner 220 connected to the plurality of radio wave emission units 51, 52, which combines and outputs high-frequency signals from the plurality of radio wave emission units 51, 52. This configuration makes it possible to arbitrarily increase the output power.

[0131] In the radio wave emission device 1A, a signal generating unit 2A generates a plurality of high-frequency signals. A plurality of power amplifiers 41, 42 respectively amplify the plurality of high-frequency signals. A plurality of radio wave emission units 51, 52 output the plurality of high-frequency signals amplified by the plurality of power amplifiers 41, 42 to a combiner 220. This configuration makes it possible to arbitrarily increase the output power with a simple configuration.

[0132] The radio wave emission device 1A described above includes a first unit 11 including a signal generating unit 2 and one or more second units 12 that do not include a signal generating unit 2. Each of the first unit 11 and the one or more second units 12 includes a power amplifier 41, 42, a radio wave emission unit 51, 52, a forward wave power measurement unit 151, 152, a reflected wave power measurement unit 161, 162, a control unit 71, 72, and a communication unit 61A, 62A. The communication unit 61A, 62A includes communication terminals 611, 612, 621, 622 and synchronization terminals 614, 624. When the control units 71, 72 execute the control of the power amplifiers 41, 42 in the first control, the control units 71, 72 output a communication signal indicating the control content of the power amplifiers 41, 42 from the communication terminals 611, 612, 621, 622. When the control units 71, 72 receive a communication signal from another control unit 71, 72 via the communication terminals 611, 612, 621, 622, they control the power amplifier units 41, 42 according to the control content of the power amplifier units 41, 42 indicated by the communication signal. In the first control, the control units 71, 72 perform operations in synchronization with the other control units 71, 72 based on the synchronization signal received via the synchronization terminals 614, 624. This configuration can improve the possibility that the radiation target will reach the target state, and further improve the energy efficiency of the radio waves.

[0133] In the radio wave emission device 1A, the control units 71 and 72 set the power of the forward wave to a second power value at the start of the first control, and control the power amplifiers 41 and 42 to reduce the power of the forward wave from the second power value so that it does not become less than the first power value when the power of the reflected wave exceeds a threshold. The control content of the power amplifiers 41 and 42 includes the amount of reduction in the power of the forward wave. This configuration can improve the possibility that the radiation target will reach the target state and further improve the energy efficiency of the radio wave.

[0134] In the radio wave emission device 1A, the control units 71 and 72 switch from the first control to the second control independently of the other control units 71 and 72. This configuration enables improvement in the responsiveness of each of the first unit 11A and the one or more second units 12.

[0135] In the radio wave emission device 1A, the control units 71 and 72 perform the second control independently of the other control units 71 and 72. This configuration enables improvement in the responsiveness of each of the first unit 11A and the one or more second units 12.

[0136] In the radio wave emission device 1A, the control unit 71 of the first unit 11A controls the signal generating unit 2 and the power amplifying unit 41 based on the power of the forward wave measured by the forward wave power measuring unit 151 and the power of the reflected wave measured by the reflected wave power measuring unit 161. This configuration can improve the possibility that the object to be radiated will reach the target state, and further improve the energy efficiency of the radio waves.

[0137] 11 is a diagram illustrating a synchronization method of a radio wave emission device 1B according to embodiment 4. The radio wave emission device 1B includes a first unit 11B and one or more second units 12 (12-1 to 12-7).

[0138] Unlike the third embodiment, in this embodiment, a synchronization signal is provided to the first unit 11B from the control device 210. In the control device 210, the control section 212 can output the synchronization signal.

[0139] 12 is a schematic circuit diagram of a first example of the first unit 11B (hereinafter referred to as the first unit 11B1). The first unit 11B1 differs from the first unit 11A1 mainly in that the first unit 11B1 includes a communication unit 61B instead of the communication unit 61A. The communication unit 61B includes a synchronization terminal 614B. The synchronization terminal 614B is a terminal for a synchronization signal. In this embodiment, the synchronization signal is output from the synchronization terminal 614B.

[0140] 13 is a schematic circuit diagram of a second example of the first unit 11B (hereinafter referred to as first unit 11B2). The first unit 11B2 differs from the first unit 11A2 mainly in that it includes a communication unit 61B instead of the communication unit 61A.

[0141] In both first unit 11B1 and first unit 11B2, control unit 71 performs operations based on a synchronization signal received through communication terminal 611 of communication unit 61B. Specifically, control unit 71 controls the emission of radio waves from radio wave emission unit 51 based on the synchronization signal. In this embodiment, communication terminal 611 is used as a synchronization terminal for receiving the synchronization signal.

[0142] 11, the first unit 11B and the second units 12-1 to 12-7 are daisy-chained to the control device 210 for the synchronization signal. Specifically, the control device 210 outputs the synchronization signal to the communication terminal 611 of the first unit 11B. The synchronization terminal 614B of the first unit 11B is connected to the input terminal 624a of the synchronization terminal 624 of the second unit 12-1, and the output terminal 624b of the synchronization terminal 624 of the second unit 12-1 is connected to the input terminal 624a of the synchronization terminal 624 of the second unit 12-2. Thereafter, the output terminal 624b of the synchronization terminal 624 of the second units 12-3 to 12-6 is connected to the input terminal 624a of the synchronization terminal 624 of the second units 12-4 to 12-7 in the subsequent stage. As a result, the synchronization signal output from the control device 210 is transmitted in sequence to the first unit 11B and the second units 12-1 to 12-7. This allows the first unit 11B and one or more second units 12-1 to 12-7 to operate in synchronization with each other using the synchronization signal.

[0143] [1.4.2 Effects, etc.] In radio wave emission device 1B, communication unit 61B includes a synchronization terminal (communication terminal 611), and communication unit 62A includes a synchronization terminal 624. Control unit 71 performs operations based on a synchronization signal received through the synchronization terminal (communication terminal 611). Control unit 72 performs operations based on a synchronization signal received through synchronization terminal 624. This configuration enables synchronization between first unit 11B and one or more second units 12.

[0144] 14 is a diagram illustrating a synchronization method of a radio wave emission device 1C according to embodiment 5. The radio wave emission device 1C includes a first unit 11C and one or more second units 12C (12C-1 to 12C-7).

[0145] FIG. 15 is a schematic circuit diagram of a first example of the first unit 11C (hereinafter referred to as the first unit 11C1). The first unit 11C1 differs from the first unit 11A1 mainly in that it includes a communication unit 61C1 instead of the communication unit 61A. The communication unit 61C1 includes a plurality of synchronization terminals 614. Each of the plurality of synchronization terminals 614 is connected to the control unit 71. The number of synchronization terminals 614 is set to be equal to or greater than the number of the one or more second units 12C (12C-1 to 12C-7). This allows synchronization signals to be provided in parallel from the first unit 11C1 to one or more second units 12C (12C-1 to 12C-7).

[0146] FIG. 16 is a schematic circuit diagram of a second example of the first unit 11C (hereinafter referred to as the first unit 11C2). The first unit 11C2 differs from the first unit 11A1 mainly in that it includes a communication unit 61C2 instead of the communication unit 61A. The communication unit 61C2 includes a plurality of synchronization terminals 614. Each of the plurality of synchronization terminals 614 is connected to an output terminal of a buffer amplifier 614d, and an input terminal of the buffer amplifier 614d is connected to the control unit 71. The number of synchronization terminals 614 is set to be equal to or greater than the number of second units 12C (12C-1 to 12C-7). This allows synchronization signals to be provided in parallel from the first unit 11C2 to one or more second units 12C (12C-1 to 12C-7).

[0147] 17 is a schematic circuit diagram of a third example of the first unit 11C (hereinafter referred to as first unit 11C3). The first unit 11C3 differs from the first unit 11A2 mainly in that it includes a communication unit 61C1 instead of the communication unit 61A.

[0148] 18 is a schematic circuit diagram of a fourth example of the first unit 11C (hereinafter referred to as first unit 11C4). The first unit 11C4 differs from the first unit 11A2 mainly in that it includes a communication unit 61C2 instead of the communication unit 61A.

[0149] In each of first units 11C1 to 11C4, control unit 71 performs operations based on the synchronization signal. Specifically, control unit 71 controls the emission of radio waves from radio wave emitter 51 based on the synchronization signal. In this embodiment, control unit 71 outputs the synchronization signal from synchronization terminal 614.

[0150] 19 is a schematic circuit diagram of an example of the second unit 12C. The second unit 12C differs from the second unit 12 mainly in that it includes a communication unit 62C instead of the communication unit 62A. The communication unit 62C includes a synchronization terminal 624C. The synchronization terminal 624C has the same configuration as the input terminal 624a of the synchronization terminal 624.

[0151] 14, with regard to the synchronization signal, the second units 12C-1 to 12C-7 are connected in parallel to the first unit 11C. Specifically, the synchronization terminals 624C of the second units 12C-1 to 12C-7 are connected to the multiple synchronization terminals 614 of the first unit 11C, respectively. This allows the synchronization signal output from the first unit 11C to be simultaneously transmitted to the second units 12C-1 to 12C-7. This enables the first unit 11C and one or more second units 12C-1 to 12C-7 to operate in synchronization with each other via the synchronization signal.

[0152] [1.5.2 Effects, etc.] In the radio wave emission device 1C, the communication units 61C1 and 61C2 include one or more synchronization terminals 614, and the communication unit 62C includes a synchronization terminal 624C. The control unit 71 performs operations based on synchronization signals and outputs synchronization signals from the one or more synchronization terminals 614 to the synchronization terminals 624C of one or more second units 12C-1 to 12C-7. The control unit 72 performs operations based on synchronization signals received via the synchronization terminal 624C. This configuration enables synchronization between the first unit 11C and one or more second units 12C.

[0153] 20 is a diagram illustrating a synchronization method of a radio wave emission device 1D according to embodiment 6. The radio wave emission device 1D includes a first unit 11D and one or more second units 12C (12C-1 to 12C-7).

[0154] Unlike the fifth embodiment, in this embodiment, a synchronization signal is provided to the first unit 11D and one or more second units 12C (12C-1 to 12C-7) from the control device 210. In the control device 210, the control unit 212 can output the synchronization signal.

[0155] 21 is a schematic circuit diagram of a first example of the first unit 11D (hereinafter referred to as the first unit 11D1). The first unit 11D1 differs from the first unit 11B1 mainly in that it includes a communication unit 61D instead of the communication unit 61B. The communication unit 61D includes a synchronization terminal 614D. The synchronization terminal 614D has the same configuration as the synchronization terminal 614B.

[0156] 22 is a schematic circuit diagram of a second example of the first unit 11D (hereinafter referred to as first unit 11D2). The first unit 11D2 differs from the first unit 11B2 mainly in that it includes a communication unit 61D instead of the communication unit 61B.

[0157] In both the first unit 11D1 and the first unit 11D2, the control unit 71 performs operations based on a synchronization signal received via the synchronization terminal 614D of the communication unit 61D. Specifically, the control unit 71 controls the emission of radio waves from the radio wave emission unit 51 based on the synchronization signal.

[0158] 20, with regard to the synchronization signal, the first unit 11B and the second units 12-1 to 12-7 are connected in parallel to the control device 210. Specifically, the control device 210 is connected to the synchronization terminal 614D of the first unit 11D and the synchronization terminals 624C of the second units 12C-1 to 12C-7. This causes the synchronization signal output from the control device 210 to be transmitted simultaneously to the first unit 11D and the second units 12C-1 to 12C-7. This enables the first unit 11D and one or more of the second units 12C-1 to 12C-7 to operate in synchronization with each other via the synchronization signal.

[0159] [1.6.2 Effects, etc.] In the radio wave emission device 1D, the communication unit 61D includes a synchronization terminal 614D, and the communication unit 62C includes a synchronization terminal 624C. The control unit 71 performs operations based on a synchronization signal received through the synchronization terminal 614D. The control unit 72 performs operations based on a synchronization signal received through the synchronization terminal 624C. This configuration enables synchronization between the first unit 11D and one or more second units 12C.

[0160] [2. Modifications] The embodiments of the present disclosure are not limited to the above-described first to sixth embodiments. The above-described first to sixth embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described first to sixth embodiments are listed below. The modifications described below can be applied in appropriate combinations. Note that, below, reference will be made to the symbols used in the first embodiment, even if they are applicable to any of the above-described first to sixth embodiments. However, this is merely to simplify the description and is not intended to exclude application to the second to sixth embodiments.

[0161] In one modified example, the control unit 71 may determine that a change to the target state of the radiation target has occurred when a decrease in the power of the reflected wave occurs multiple times consecutively within a predetermined period. In this case, the possibility of determining that a change to the target state of the radiation target has occurred due to a decrease in the power of the reflected wave caused by noise or the like, i.e., the possibility of erroneous detection, can be reduced. Here, the control unit 71 may determine that a decrease in the power of the reflected wave has occurred when the rate of decrease in the power of the reflected wave is equal to or greater than a predetermined value.

[0162] In one modified example, the control unit 71 may switch from the second control to the first control when it determines that the radiation target is not maintained in the target state in the second control. In this case, after switching to the second control, if the radiation target is no longer in the target state for some reason (for example, if the plasma is extinguished), the first control can be executed again. Note that whether the radiation target is maintained in the target state can be determined based on the power of the reflected wave or the state (temperature, pressure, etc.) within the chamber 140.

[0163] In one modified example, the radio wave emission device 1 may include a temperature sensor that directly or indirectly measures the temperature inside the chamber 140 or the temperature of the emission object. In this case, the control unit 71 may be configured to change the high-frequency signal from a continuous wave to a pulse wave when the temperature inside the chamber 140 or the temperature of the emission object reaches or exceeds a predetermined temperature, after determining that a change to the target state of the emission object has occurred based on the power of the reflected wave. This configuration can reduce the energy of the radio waves emitted into the chamber 140, and can reduce the temperature rise inside the chamber 140.

[0164] In one modified example, the control unit 71 may not be configured to control the power of the forward wave in accordance with the power of the reflected wave in the first control. As an example, in the first control, the control unit 71 may control the power amplifier 41 so that the power of the forward wave is the first power value from the beginning.

[0165] In one modified example, the control unit 71 may control the power amplifier unit 41 so that the power of the traveling wave becomes a third power value that is greater than the first power value and less than the second power value when the first control continues for a predetermined time. The predetermined time is set to be longer than the time it takes for the radiation target to change to the target state in the first control. As an example, if the time it takes for the radiation target to change to the target state is 100 ms to 800 ms, the predetermined time may be 60 s. As an example, if the first power value is 60% of the second power value, the third power value may be 80% of the second power value.

[0166] In one modified example, in the second control, when the power of the reflected wave is equal to or greater than a threshold, the control unit 71 may control the power amplifier 41 so that the power of the forward wave becomes a third power value that is greater than the first power value and less than the second power value, thereby protecting the radio wave emission device 1.

[0167] In one modified example, the control unit 71 may be configured to control the frequency of the high-frequency signal in accordance with the power of the reflected wave in the first control. Here, the control of the frequency of the high-frequency signal may be set to be performed at the minimum control cycle of the control unit 71. This enables improved responsiveness. When the power of the reflected wave is equal to or greater than a threshold, the control unit 71 may change the frequency of the high-frequency signal so that the power of the reflected wave is reduced. This makes it possible to irradiate the target with a high-frequency signal of a frequency suitable for the target, which enables improved energy efficiency.

[0168] In one modified example, there is no particular limitation on the number of second units 12 that can be connected to the first unit 11. In other words, there is no particular limitation on the number of high-frequency signals generated by the signal generating unit 2A, the number of output terminals 811 of the output unit 81, etc.

[0169] As described above, the first unit 11 includes a signal generating unit 2A, but one or more of the second units 12 do not include a signal generating unit 2A. Here, as shown in FIGS. 7 and 8 , the signal generating unit 2A includes a power adjusting unit 22 that adjusts the power of the high-frequency signal generated by the signal generating unit 2A. Therefore, in one modified example, the control unit 71 of the first unit 11 controls the power adjusting unit 22 of the signal generating unit 2A to simultaneously adjust the power of not only the first unit 11 but also one or more second units 12 in synchronization with each other. As an example, the control unit 71 of the first unit 11 can set the power of the forward wave to a second power value at the start of the first control, and control the power adjusting unit 22 to reduce the power of the forward wave from the second power value when the power of the reflected wave exceeds a threshold value so that it does not fall below the first power value. In this case, the power can be adjusted collectively without transmitting a synchronization signal from the first unit 11 to the second units 12.

[0170] In one modification, the signal generating section 2 may not include the power adjusting section 22 .

[0171] In one variant, the signal generating unit 2A may include an oscillator circuit and a multi-output frequency synthesizer. The oscillator circuit may generate a reference signal. The reference signal is a signal in a frequency band lower than the multiple high-frequency signals. As an example, the frequency band of the reference signal is approximately several tens of megahertz, and the frequency band of the high-frequency signals is approximately 2400 MHz to 2500 MHz. The oscillator circuit, for example, converts commercial AC power to DC power and generates the reference signal by voltage control using a semiconductor supplied with the DC power. The multi-output frequency synthesizer generates multiple high-frequency signals with the same frequency band and phase based on the reference signal. The multi-output frequency synthesizer may be configured to output, for example, up to eight high-frequency signals. One of the eight high-frequency signals is used by the first unit 11, and the remaining seven are used by the second unit 12.

[0172] In the above embodiment, the divider 24 outputs a plurality of high-frequency signals by equally dividing the high-frequency signal from the oscillation circuit 21. As a result, the divider 24 outputs high-frequency signals having the same frequency band as the high-frequency signal from the oscillation circuit 21. However, the divider 24 does not necessarily divide the high-frequency signal from the oscillation circuit 21 equally. As a modified example, the phase of the high-frequency signal input to the divider 24 and the phase of the high-frequency signal input to and output from the output terminal 811 may be different. Furthermore, when connecting to a phased array antenna or the like via the radio wave emitting units 51 and 52 and performing beamforming or the like, the phases of the high-frequency signals output from the radio wave emitting units 51 and 52 may be set to be different from each other.

[0173] In one modification, the radio wave emitting device 1 may include a phase adjuster, i.e., the radio wave emitting device 1 may be configured to be able to adjust the phase of the high frequency signal.

[0174] In the radio wave emission device 1A, the phases of the radio waves emitted from the first unit 11 and the second unit 12 may be the same or different. The control unit 71 may adjust the phase of the radio frequency signal using a phase adjuster. For example, the control unit 71 can adjust the phase of the radio frequency signal to a phase target value using the phase adjuster. The phase target value may be provided by a communication signal. When the control unit 72 adjusts the phases of the radio waves emitted from the first unit 11 and the second unit 12 to be the same, the control unit 72 may adjust the phase of the radio frequency signal using the adjustment unit 32 so that the phase difference between the radio frequency signal from the first unit 11 and the radio frequency signal from the second unit 12 becomes zero. For example, the control unit 72 adjusts the phase of the radio frequency signal using the adjustment unit 32 to a phase target value. The phase target value may be provided by a communication signal.

[0175] In one variant, the first unit 11 and the second unit 12 may automatically adjust the phase and / or power.

[0176] In one modification, the number of combiners 1211 and 1212 or the number of combiners 1221 and 1222 is not particularly limited.

[0177] In one modified example, there is no particular limitation on the number of temperature sensors 1411 and 1412 or the number of temperature sensors 1421 and 1422. Current sensors may be used instead of the temperature sensors 1411, 1412, 1421, and 1422. The temperature sensors 1411, 1412, 1421, and 1422 are not essential.

[0178] In one modification, the first unit 11 and the second unit 12 may communicate with each other. For example, a communication path may be formed between the second communication terminal 612 of the communication section 61 of the first unit 11 and the second communication terminal 622 of the communication section 62 of the second unit 12.

[0179] [3. Aspects] As is clear from the above-described embodiment and modifications, the present disclosure includes the following aspects.

[0180] a power amplifier that amplifies the high frequency signal; a radio wave emitting unit that enables radio wave emission into a chamber that accommodates a radiation object based on the high frequency signal amplified by the power amplifier; a forward wave power measuring unit that measures the power of a forward wave that is the high frequency signal amplified by the power amplifier; a reflected wave power measuring unit that measures the power of a reflected wave that flows back from the radio wave emitting unit; and a control unit that controls the power amplifier based on the power of the forward wave measured by the forward wave power measuring unit and the power of the reflected wave measured by the reflected wave power measuring unit, wherein the control unit executes first control to control the power amplifier unit so that the power of the forward wave is equal to or greater than a first power value for causing the radiation object to change to a target state, and when it is determined based on the power of the reflected wave that a change to the target state has occurred in the radiation object, switches from the first control to second control to control the power amplifier unit so that the power of the forward wave is equal to or greater than a second power value that is greater than the first power value.

[0181] [Aspect 2] The radio wave emission device of aspect 1, wherein the first power value is equal to or greater than 60% and less than 100% of the second power value.

[0182] [Aspect 3] The radio wave emission device according to Aspect 1 or 2, wherein the control unit determines that the emission target has changed to a target state when a rate of decrease in the power of the reflected wave within a predetermined period is equal to or greater than a predetermined value.

[0183] [Aspect 4] The radio wave emission device of Aspect 3, wherein the predetermined period is 1 ms or more and 5 seconds or less.

[0184] [Aspect 5] The radio wave emission device according to aspect 3 or 4, wherein the predetermined value is 10%.

[0185] [Aspect 6] The radio wave emission device according to any one of Aspects 1 to 5, wherein, when switching from the first control to the second control, the control unit controls the power amplifier unit so that the power of the traveling wave becomes equal to or greater than the second power value within a specified period of time after determining that a change to the target state of the emission object has occurred.

[0186] [Aspect 7] The radio wave emission device of Aspect 6, wherein the specified period is 1 ms or more and 40 ms or less.

[0187] [Aspect 8] The radio wave emission device according to any one of Aspects 1 to 7, wherein the control unit controls the power amplifier unit so that the power of the traveling wave becomes a third power value that is greater than the first power value and less than the second power value when the first control continues for a predetermined time.

[0188] [Aspect 9] The radio wave emission device according to any one of Aspects 1 to 8, wherein the control unit is configured to control the power of the forward wave in accordance with the power of the reflected wave in the first control.

[0189] [Aspect 10] The radio wave emission device of Aspect 9, wherein the control unit sets the power of the forward wave to the second power value at the start of the first control, and controls the power amplifier unit to reduce the power of the forward wave from the second power value so as not to become less than the first power value when the power of the reflected wave exceeds a threshold.

[0190] [Aspect 11] The radio wave emission device according to any one of Aspects 1 to 10, wherein the control unit is configured to control the frequency of the high frequency signal in accordance with the power of the reflected wave in the first control.

[0191] [Aspect 12] The radio wave emission device according to any one of Aspects 1 to 11, wherein the control unit determines that a change to the target state of the emission object has occurred based on the power of the reflected wave, and then changes the high-frequency signal from a continuous wave to a pulse wave when the power of the forward wave becomes equal to or greater than the second power value or when the temperature inside the chamber or the temperature of the emission object becomes equal to or greater than a predetermined temperature.

[0192] [Aspect 13] The radio wave emission device according to Aspect 12, wherein the control unit controls an attenuation rate of the pulsed high-frequency signal in synchronization with a pulse period of the pulsed high-frequency signal.

[0193] [Aspect 14] The radio wave emission device according to any one of Aspects 1 to 13, comprising: a plurality of the power amplification units; a plurality of the radio wave emission units; and a combiner connected to the plurality of radio wave emission units, which combines and outputs the high-frequency signals from the plurality of radio wave emission units.

[0194] [Aspect 15] The radio wave emitting device of Aspect 14, wherein the signal generating unit generates a plurality of the high frequency signals; the plurality of power amplifiers amplify the plurality of high frequency signals, respectively; and the plurality of radio wave emitting units output the plurality of high frequency signals amplified by the plurality of power amplifiers, respectively, to the combiner.

[0195] [Aspect 16] A radio wave emitting device according to Aspect 14 or 15, comprising: a first unit including the signal generating unit; and one or more second units not including the signal generating unit, wherein each of the first unit and the one or more second units comprises the power amplifier, the radio wave emitting unit, the forward wave power measuring unit, the reflected wave power measuring unit, the control unit, and a communication unit, wherein the communication unit comprises a communication terminal and a synchronization terminal, wherein when the control unit executes control of the power amplifier in the first control, it outputs a communication signal indicating control content of the power amplifier from the communication terminal, and when the control unit receives the communication signal from another control unit via the communication terminal, it executes control of the power amplifier in accordance with the control content of the power amplifier indicated by the communication signal, and the control unit executes operation in the first control in synchronization with the other control unit based on the synchronization signal received via the synchronization terminal.

[0196] [Aspect 17] The radio wave emission device of Aspect 16, wherein the control unit sets the power of the forward wave to the second power value at the start of the first control, and controls the power amplifier unit to reduce the power of the forward wave from the second power value so that the power does not become less than the first power value when the power of the reflected wave exceeds a threshold, and the control content of the power amplifier unit includes the amount of reduction in the power of the forward wave.

[0197] [Aspect 18] The radio wave emission device according to aspect 16 or 17, wherein the control unit switches from the first control to the second control independently of another control unit.

[0198] [Aspect 19] The radio wave emission device according to any one of Aspects 16 to 18, wherein the control unit executes an operation independently of another control unit in the second control.

[0199] [Aspect 20] The radio wave emission device according to any one of Aspects 16 to 19, wherein the control unit of the first unit controls the signal generation unit and the power amplification unit based on the power of the forward wave measured by the forward wave power measurement unit and the power of the reflected wave measured by the reflected wave power measurement unit.

[0200] [Aspect 21] The radio wave emission device of Aspect 14, comprising: a first unit including the signal generating unit; and one or more second units not including the signal generating unit, wherein the signal generating unit has a power adjusting unit that adjusts the power of the high frequency signal generated by the signal generating unit.

[0201] [Aspect 22] The radio wave emission device of Aspect 21, wherein the control unit of the first unit sets the power of the forward wave to the second power value at the start of the first control, and controls the power adjustment unit to reduce the power of the forward wave from the second power value when the power of the reflected wave exceeds a threshold value so that the power does not become less than the first power value.

[0202] Aspects 2 to 22 are optional elements and are not essential.

[0203] The present disclosure is applicable to radio wave emitting devices, and more particularly to radio wave emitting devices for changing the state of an object from which radiation is emitted.

[0204] 1, 1A Radio wave emission device 2, 2A Signal generation unit 41, 42 Power amplification unit 51, 52 Radio wave emission unit 71, 72 Control unit 140 Chamber 151, 152 Forward wave power measurement unit 161, 162 Reflected wave power measurement unit 220 Combiner

Claims

a power amplifier that amplifies the high-frequency signal; a radio wave emitting unit that enables radio wave emission into a chamber that contains an object to be radiated based on the high-frequency signal amplified by the power amplifier; a forward wave power measuring unit that measures the power of a forward wave that is the high-frequency signal amplified by the power amplifier; a reflected wave power measuring unit that measures the power of a reflected wave that flows back from the radio wave emitting unit; and a control unit that controls the power amplifier based on the power of the forward wave measured by the forward wave power measuring unit and the power of the reflected wave measured by the reflected wave power measuring unit, wherein the control unit executes first control to control the power amplifier so that the power of the forward wave is equal to or greater than a first power value for causing the object to change to a target state, and when it is determined based on the power of the reflected wave that a change to the target state has occurred in the object to be radiated, switches from the first control to second control to control the power amplifier so that the power of the forward wave is equal to or greater than a second power value that is greater than the first power value.

2. The radio wave emitting device according to claim 1, wherein the first power value is equal to or greater than 60% and less than 100% of the second power value.

3. The radio wave emitting device according to claim 1, wherein the control unit determines that a change to the target state of the object to be emitted has occurred when a rate of decrease in the power of the reflected wave within a predetermined period of time is equal to or greater than a predetermined value.

4. The radio wave emitting device according to claim 3, wherein the predetermined period is between 1 ms and 5 seconds.

5. The radio wave emitting device according to claim 3, wherein the predetermined value is 10%.

6. The radio wave emission device of claim 1, wherein, when switching from the first control to the second control, the control unit controls the power amplifier unit so that the power of the traveling wave becomes equal to or greater than the second power value within a specified period after determining that a change to the target state of the emission object has occurred.

7. The radio wave emitting device according to claim 6, wherein the specified period is between 1 ms and 40 ms.

8. The radio wave emitting device according to claim 1, wherein the control unit controls the power amplifier unit so that the power of the traveling wave becomes a third power value that is greater than the first power value and less than the second power value when the first control continues for a predetermined time.

9. The radio wave emitting device according to claim 1, wherein the control unit is configured to control the power of the forward wave in accordance with the power of the reflected wave in the first control.

10. The radio wave emitting device of claim 9, wherein the control unit sets the power of the forward wave to the second power value when the first control starts, and controls the power amplifier unit to reduce the power of the forward wave from the second power value so that it does not become less than the first power value when the power of the reflected wave exceeds a threshold value.

11. The radio wave emitting device according to claim 1, wherein the control unit is configured to control the frequency of the high frequency signal in accordance with the power of the reflected wave in the first control.

12. The radio wave emission device of claim 1, wherein the control unit determines that a change to the target state of the emission object has occurred based on the power of the reflected wave, and then changes the high-frequency signal from a continuous wave to a pulse wave when the power of the forward wave becomes equal to or greater than the second power value or when the temperature inside the chamber or the temperature of the emission object becomes equal to or greater than a predetermined temperature.

13. The radio wave emitting device according to claim 12, wherein the control unit controls the attenuation rate of the pulse-shaped high-frequency signal in synchronization with the pulse period of the pulse-shaped high-frequency signal.

14. The radio wave emitting device according to claim 1, comprising: a plurality of said power amplifiers; a plurality of said radio wave emitting units; and a combiner connected to said plurality of radio wave emitting units, which combines and outputs the high frequency signals from said plurality of radio wave emitting units.

15. The radio wave emitting device according to claim 14, wherein the signal generating section generates a plurality of the high frequency signals, the plurality of power amplifiers respectively amplify the plurality of high frequency signals, and the plurality of radio wave emitting sections output the plurality of high frequency signals respectively amplified by the plurality of power amplifiers to the combiner.

16. A radio wave emitting device according to claim 14, comprising: a first unit having the signal generating section; and one or more second units not having the signal generating section, wherein each of the first unit and the one or more second units comprises the power amplifier section, the radio wave emitting section, the forward wave power measuring section, the reflected wave power measuring section, the control section, and a communication section, wherein the communication section has a communication terminal and a synchronization terminal, wherein when the control section executes control of the power amplifier section in the first control, it outputs a communication signal indicating the control content of the power amplifier section from the communication terminal, and when the control section receives the communication signal from another control section through the communication terminal, it executes control of the power amplifier section in accordance with the control content of the power amplifier section indicated by the communication signal, and wherein the control section executes operation in the first control in synchronization with the other control section based on the synchronization signal received through the synchronization terminal.

17. The radio wave emitting device of claim 16, wherein the control unit sets the power of the forward wave to the second power value when the first control starts, and controls the power amplifier unit to reduce the power of the forward wave from the second power value when the power of the reflected wave exceeds a threshold value so that the power does not become less than the first power value, and the control content of the power amplifier unit includes the amount of reduction in the power of the forward wave.

18. The radio wave emitting device according to claim 16, wherein the control unit switches from the first control to the second control independently of another control unit.

19. The radio wave emitting device according to claim 16, wherein the control unit performs an operation independently of another control unit in the second control.

20. The radio wave emitting device of claim 16, wherein the control unit of the first unit controls the signal generating unit and the power amplifying unit based on the power of the forward wave measured by the forward wave power measuring unit and the power of the reflected wave measured by the reflected wave power measuring unit.

21. The radio wave emitting device of claim 14, comprising: a first unit having the signal generating section; and one or more second units not having the signal generating section, wherein the signal generating section has a power adjusting section that adjusts the power of the high frequency signal generated by the signal generating section.

22. The radio wave emitting device of claim 21, wherein the control unit of the first unit sets the power of the forward wave to the second power value when the first control starts, and controls the power adjustment unit to reduce the power of the forward wave from the second power value so that it does not become less than the first power value when the power of the reflected wave exceeds a threshold value.

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