JP3900524B2 - High frequency power supply and ICP emission spectroscopic analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency power source for plasma used as a light source of an ICP emission spectroscopic analysis device, and an ICP emission spectroscopic analysis device including a high-frequency power source.
[0002]
[Prior art]
The ICP emission spectroscopic analyzer performs sample analysis by introducing a sample into plasma excited by high frequency induction to excite atoms of the sample to emit atomic spectral lines and analyzing this light. In general, an ICP emission spectroscopic analysis apparatus includes a plasma light emitting unit, a light emission / spectrophotometry unit, and a recording / display unit. The plasma light emission unit includes a high frequency power source, a gas supply / control unit, a sample introduction unit, and the like. In the plasma light emitting part, an induction coil is wound around a discharge tube called a torch, an induction electric field is generated by supplying a high frequency current from a high frequency power source to this coil, and argon gas is introduced into the torch to form plasma, By introducing the atomized sample into the plasma, the atoms of the sample are excited to emit atomic spectral lines.
[0003]
The high-frequency power source of the ICP emission spectroscopic analyzer needs to efficiently supply power into the plasma. When high-frequency current is supplied from the high-frequency power source to the induction coil, if the impedance between the high-frequency power source and the induction coil is not matched, a part of the supply current is returned to the high-frequency power source as a reflected wave. The power supply efficiency decreases. For example, if the load on the plasma side fluctuates, mismatching between the high-frequency power source and the induction coil occurs, and the power supply efficiency into the plasma is reduced. Thus, the reflected wave from the induction coil is observed, and plasma lighting is performed under the condition that the reflected wave becomes small.
[0004]
As a configuration for reducing the reflected wave, a matching box is provided between the high-frequency power source and the induction coil, and impedance matching is performed by changing the capacitor capacity with this matching box. In the matching box, the capacity of the capacitor is changed by the motor. In this matching box, an instruction to increase or decrease the capacitance of the capacitor is made by detecting the phase of the voltage and current supplied to the matching box.
[0005]
The phase detection of the voltage and current is performed by a voltage signal obtained by dividing from a high frequency power line connected to the matching box and a current signal obtained by using current detection means such as a Rogowski coil.
[0006]
The detected phase detection signal is rectified into a DC analog signal, and this analog signal is sent to the motor control circuit via the signal line to drive the motor for impedance matching.
[0007]
As described above, for example, Patent Document 1 discloses a high-frequency device that changes the capacitor capacity of a matching box using a motor based on the phase of a high-frequency voltage and current input to the matching box.
[0008]
[Patent Document 1]
JP-A-5-345972 (FIG. 4)
[0009]
[Problems to be solved by the invention]
In the conventional high frequency power supply for plasma, the phase detection signal obtained by detecting the high frequency voltage and current input to the matching box is sent to the motor control circuit via a signal line in the form of an analog signal. There is a problem that noise may be added to the signal line.
[0010]
Normally, the motor control circuit is installed on a common control board together with other control circuits, and if the signal line sent to the motor control circuit contains noise, this noise causes other control circuits to malfunction. There is a risk.
[0011]
In particular, in places where an induction electric field or the like is generated as in an ICP emission spectroscopic analyzer, the signal line is susceptible to high-frequency noise, and if other control circuits malfunction, the ICP emission spectroscopic analysis is affected. May occur.
[0012]
Accordingly, an object of the present invention is to solve the above-described conventional problems and provide a high-frequency power source that is not easily affected by noise and a high-frequency power source for an ICP emission spectroscopic analyzer.
[0013]
[Means for Solving the Problems]
In the phase detection of the high frequency power supplied to the high frequency power source, the present invention can eliminate the influence of noise on the signal by outputting the phase detection signal as an optical signal, and further, by outputting the optical signal as a digital value. The speed at which the phase adjustment is performed can be changed according to the adjustment amount.
[0014]
The high-frequency power source of the present invention includes a variable capacitor, a matching box that matches impedance between the high-frequency power line and the load and supplies high-frequency power to the load, and high-frequency voltage and current supplied to the matching box. Phase detecting means for detecting the phase of the output and outputting it as an optical signal, and adjusting means for adjusting the capacitance of the variable capacitor of the matching box based on the optical signal.
[0015]
The matching box supplies the high frequency power input from the high frequency power line to a load such as plasma. At this time, by adjusting the capacitance of the variable capacitor, the impedance between the high-frequency power line and the load is matched to reduce the reflected wave, and the power supply efficiency is increased.
[0016]
The phase detection means detects the voltage and current phases of the high-frequency power input to the matching, and sends a phase detection signal to the adjustment means as an optical signal. The adjusting means adjusts the capacitance of the variable capacitor of the matching box based on the phase detection signal based on the optical signal.
[0017]
The phase detection means can remove the influence of noise on the signal by sending the phase detection signal in the form of an optical signal, and can prevent malfunction of other control circuits.
[0018]
Further, the phase detection means detects the distance between the detected phase position and the target phase position by the number of lighting of the plurality of light emitting elements or a digital value by the lighted light emitting elements. The adjusting means adjusts the phase adjustment speed by changing the speed for adjusting the variable capacitor capacity according to the digital value. In this way, by adjusting the position adjustment speed according to the distance between the detected phase position and the target phase position, fluctuations called hunting can be prevented in the vicinity of the target phase position.
[0019]
For example, if the distance between the detected phase position and the target phase position is large, the number of light-emitting elements is increased to inform the adjustment means that the amount of phase position deviation is large, and the capacitor capacity is changed at high speed. . In addition, when the distance between the detected phase position and the target phase position is small, the number of light-emitting elements is reduced to inform the adjustment means that the amount of phase position deviation is small, and the capacitor capacity is changed at a low speed. . In this way, the amount of deviation can be adjusted at high speed while the amount of phase position deviation is large, and the amount of deviation can be adjusted at low speed when the amount of deviation is small, thus preventing fluctuation due to excessive adjustment near the target phase position. be able to. Note that the number of lighting elements of the light emitting element can be set in reverse. Further, the light emitting element to be lit may correspond to the shift amount of the phase position.
[0020]
Further, the phase detection means can change the detection sensitivity and the target phase position. In the configuration for changing the detection sensitivity, a variable resistor is connected in series to each light emitting element. The detection sensitivity of each light emitting element is made variable by adjusting the resistance value of each variable resistor.
[0021]
Moreover, the structure which changes a target phase position connects one resistance so that it may become parallel with respect to each light emitting element. By adjusting the zero potential position of this resistor, the zero point of the phase detection signal is made variable, thereby adjusting the target phase position.
[0022]
Further, the ICP emission spectroscopic analysis apparatus of the present invention includes a plasma light emitting unit including the above-described high frequency power source and a spectroscopic / photometric unit. The high frequency power supply supplies high frequency power to the plasma light emitting unit. In the high-frequency power supply, the phase detection signal is in the form of an optical signal with the above configuration, so that noise is removed, malfunction of other control circuits can be prevented, and malfunction in emission spectroscopic analysis can be prevented.
[0023]
In addition, the adjustment speed to the target phase position can be varied according to the amount of deviation, so that the hunting phenomenon can be suppressed and stable emission spectroscopic analysis can be performed.
[0024]
Further, since the target phase position and detection sensitivity can be adjusted, the target phase position and detection sensitivity can be arbitrarily set according to the analysis characteristics of the ICP emission spectroscopic analyzer to be applied. For example, if the amount of phase shift when the plasma is turned on is known in advance, the target phase position is set in advance by combining this amount of shift, and the reflected wave is minimized after the plasma is turned on. One light emitting element of the phase detection signal can be turned on in a state where the reflected wave is minimized before the plasma is turned on so that the phase of the phase detection signal is zero (light emitting element is turned off).
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0026]
FIG. 1 is a schematic diagram for explaining a high-frequency power source and an ICP emission spectroscopic analyzer of the present invention.
In FIG. 1, a high frequency power source 1 of the present invention includes a matching box 2, an adjustment unit 3, and a phase detection unit 4, and an ICP emission spectroscopic analyzer 10 of the present invention includes a plasma light emitting unit 12 including the high frequency power source 1, A spectroscopic / photometric unit 13 and a recording / display unit 14 are provided.
[0027]
The matching box 2 includes a variable capacitor (not shown), and by adjusting the variable capacitor, the impedance between the high-frequency power line 5 and the load (plasma 11 in FIG. 1) is matched to the load (plasma 11). High frequency power is supplied to Impedance matching between the high-frequency power line 5 and the load (plasma 11) is obtained by reflected wave power detection, and the amount of shift and direction with respect to the phase position where the reflected wave is minimum depends on the voltage and current phase of the high-frequency power line 5. Can be detected.
[0028]
The adjusting means 3 includes a motor 3a that drives a variable capacitor provided in the matching box 2, and a motor control circuit 3b that controls the rotation direction and rotation speed of the motor 3a. The increasing / decreasing direction of the capacity of the variable capacitor can be changed by the rotating direction of the motor 3a, and the increasing / decreasing speed of the capacity of the variable capacitor can be changed by the rotating speed of the motor 3a.
[0029]
The phase detector 4 detects the phase of the high-frequency voltage and current supplied to the matching box 2 and outputs it as an optical signal. The phase detection of the high-frequency voltage and current can be performed by measuring the voltage and current of the high-frequency power line 5 that supplies the matching box 2 with high-frequency power. The phase of the high-frequency voltage and current supplied to the matching box 2 directly determines the shift amount and direction of the impedance between the high-frequency power line 5 and the load (plasma 11) to the optimal matching state (minimum reflected wave). Does not represent. The phase relationship that minimizes the reflected wave in the reflected wave power detection is adjusted so that the light emitting element is turned off. As a result, the shift amount and direction of the phase relationship that minimizes the reflected wave can be found.
[0030]
Therefore, by adjusting the variable capacitor of the matching box 2 by the adjusting means 3 based on the detected phase, the impedance matching state between the high frequency power line 5 and the load (plasma 11) can be adjusted.
[0031]
In the high frequency power source 1 of the present invention, the phase detection means 4 and the motor control circuit 3b are connected by an optical fiber 8, and the phase detection signal output from the phase detection means 4 is in the form of an optical signal in the motor control circuit 3b. Sent to.
[0032]
Conventionally, in the high-frequency power source 1, the motor control circuit 3 b and the phase detection means 4 are installed on the control board 7 together with other control circuits 9. Since the phase detection means 4 and the motor control circuit 3b are connected by an optical fiber 8, if the phase detection means 4 is placed outside the control board 7, noise is added to the phase detection signal inside the control board 7. There is no possibility of affecting the other control circuit 9, and the other control circuit 9 can prevent malfunction due to noise.
[0033]
For example, a Rogowski coil can be used as current measuring means for measuring the high-frequency current flowing in the high-frequency power line 5. In addition, the high-frequency voltage flowing in the high-frequency power line 5 can be measured by passing a capacitor between the high-frequency power line 5 and the ground.
[0034]
The plasma light emitting unit 12 includes a discharge tube called a torch 12 a that generates plasma by receiving high-frequency power supplied from the matching box 2 of the high-frequency power source 1 together with the high-frequency power source 1. An induction coil is wound around the torch 12a, and a high frequency current is supplied from the high frequency power source 1 via the matching box 2 to generate an induction electric field. Argon gas is introduced into the torch 12a to form plasma, and the atomized sample is introduced into the plasma, thereby exciting the atoms of the sample and emitting atomic spectral lines.
[0035]
The emitted atomic spectral line is spectrally divided into a desired wavelength by the spectroscopic / photometric means 13 and photometrically measured. The photometric result is recorded and / or displayed by the recording / display means 14. The plasma light emitting unit 12 including the high frequency power source 1 and the spectroscopic / photometric unit 13 constitute an ICP emission spectroscopic analysis apparatus 10. The recording / display means 14 can be provided as necessary.
[0036]
Next, a configuration example of the phase detection means 4 provided in the high frequency power source 1 of the present invention will be described with reference to FIG. The configuration surrounded by a broken line in FIG. 2 shows an example of phase detection means for outputting a phase detection signal in the form of an optical signal.
[0037]
The phase detection unit 4 takes in a voltage signal from the high-frequency power line 5 via the capacitors C1 and C2 connected in series, and takes in a current signal from the Rogowski coil 6 provided around the high-frequency power line 5.
[0038]
One end of the capacitor C2 is grounded, and the voltage at the connection point between the capacitor C1 and the capacitor C2 becomes a voltage value corresponding to the capacitance of the capacitor C1 and the capacitor C2. Here, when the capacitors C1 and C2 have the same capacity, the voltage at the connection point between the capacitors C1 and C2 is the midpoint voltage of the captured voltage signal.
[0039]
On the other hand, the captured current signal is rectified by the diodes D1 and D2, and charged to the capacitors C3 and C4 connected in series. The connection points of the capacitors C3 and C4 and the connection points of the capacitors C1 and C2 are connected via a coil, whereby the capacitors C3 and C4 are charged with voltages having the same reference potential. .
[0040]
The current flowing through the resistive load connected to the Rogowski coil is out of phase with respect to the voltages of C1 and C2, which are capacitive loads, and the voltage charged to C3 and C4 varies depending on the amount of deviation. Furthermore, this voltage difference changes by changing the load (plasma), and the phase relationship between voltage and current can be expressed.
[0041]
As a result, when a phase difference occurs between the current and the voltage due to the delay or advance of the voltage, a difference occurs between the voltage charged in the capacitor C3 and the voltage charged in C4. The direction represents the phase delay or advance direction, and the magnitude of the voltage difference represents the amount of phase shift.
[0042]
In order to output this voltage difference as an optical signal, the phase detector 4 connects a light emitting element in parallel with the capacitors C3 and C4 connected in series. For example, a light emitting diode can be used as the light emitting element. In the example shown in FIGS. 2 and 3, the state of the voltage difference in five stages is output using the four light emitting diodes LED1 to LED4.
[0043]
Here, the variable resistors VR1 to VR4 are connected in series to each of the light emitting diodes LED1 to LED4, and the series connection of the light emitting diode LED and the variable resistor VR is connected in parallel to the capacitors C3 and C4 connected in series. . Of the four light-emitting diodes, the LED1 and LED2 sets and the LED3 and LED4 sets have light-emitting diodes connected in opposite directions, and the LED1 and LED2 sets are charged to the capacitor C3 (the direction of the voltage of the C3). LED3 and LED4 emit light by the voltage charged in the capacitor C4 (when the voltage of C4 is greater than the voltage of C3).
[0044]
Note that the variable resistor VR connected to the light emitting diode LED adjusts the voltage at which the light emitting diode LED is turned on, and adjusts the detection sensitivity of the phase detection. For example, when the resistance value of the variable resistor VR is set small, the detection sensitivity can be increased because the light is lit even with a small voltage difference. Conversely, when the resistance value of the variable resistor VR is set large, the resistance value is small. The detection sensitivity can be lowered because the voltage difference does not light up.
[0045]
Since the phase direction depends on the winding direction of the Rogowski coil, it cannot be determined. That is, the direction of the Rogowski coil, the direction of the phase signal, and the direction of rotation of the motor must be carefully matched. Therefore, in FIG. 4, for example, when the current is ahead of the voltage, if the voltage charged in the capacitor C3 is larger than the voltage charged in the capacitor C4, the current flows in the direction from the capacitor C3 to the capacitor C4. Therefore, the light emitting diodes LED1 and LED2 emit light, and the light emitting diodes LED3 and LED4 do not emit light.
[0046]
In addition, when the current is behind the voltage, if the voltage charged in the capacitor C3 is smaller than the voltage charged in the capacitor C4, a voltage difference that causes the current to flow from the capacitor C4 to the capacitor C3 is generated. The light emitting diodes LED3 and LED4 emit light, and the light emitting diodes LED1 and LED2 do not emit light.
[0047]
Here, by adjusting the size of the variable resistor VR connected to each light emitting diode LED, the light emitting state of the light emitting diode LED can be changed according to the voltage difference. For example, as an example, when the resistance values of the variable resistors VR1 and VR3 are set small and the resistance values of the variable resistors VR2 and VR4 are set large, the light-emitting diodes LED1 and LED2 are turned on when the current advances with respect to the voltage. When the advance of the current is small, only the light emitting diode LED1 is lit. Further, when the current delay with respect to the voltage is large, the light emitting diodes LED3 and LED4 are turned on, and when the current delay is small, only the light emitting diode LED3 is turned on. If there is no phase shift, none of the light emitting diodes is lit. The phase detection means 4 outputs an optical signal as a phase detection signal when the light emitting diode LED is turned on. As described above, since the phase direction depends on the winding direction of the Rogowski coil and cannot be determined, the phase direction in the above example is an example.
[0048]
Further, in the phase detection means 4, a variable resistor VR5 is connected in parallel to the series connection of the light emitting diode LED and the variable resistor VR. The variable resistor VR5 sets a potential reference for turning on the light emitting diodes LED1 and 2 and the light emitting diodes LED3 and 4 connected in opposite directions, and adjusts the zero point of the phase detection signal. Thereby, when the state where none of the light emitting diodes LED is lit is set as the target phase position, the target phase position can be adjusted by the variable resistor VR5. For example, if the potential reference is shifted to the negative voltage side of the capacitor C4 by adjusting the variable resistor VR5, the zero point of the phase detection signal is also shifted to the negative voltage side of the capacitor C4, and the voltage range in which the light emitting diodes LED1 and LED2 emit light increases. The voltage range in which the light emitting diodes LED3 and 4 emit light is narrowed. Conversely, when the potential reference is shifted to the positive voltage side of the capacitor C3, the zero point of the phase detection signal is also shifted to the positive voltage side of the capacitor C3, and the voltage range in which the light emitting diodes LED1 and LED2 emit light is narrowed. The voltage range to emit light is widened.
[0049]
In the above example, the shift amount of the phase position is determined by the number of light-emitting diodes that are turned on, but the light-emitting diode may be configured to correspond to the shift amount of the phase position.
[0050]
The phase detection signal detected by the phase detection means 4 is sent to the motor control circuit 3b in the form of an optical signal to rotate the motor 3a that drives the variable capacitor of the matching box 2.
[0051]
FIG. 3 is a relationship diagram for explaining the relationship between the lighting state of the light emitting diode and the motor operation. FIG. 3C shows a case where the phase relationship between voltage and current is at the target phase position. In this case, all of the light emitting diodes of the phase detection means are turned off and the phase detection signal does not emit an optical signal, and the motor control circuit 3b controls the motor to a stop state in response to the phase detection signal.
[0052]
FIGS. 3A and 3E show a case where the phase relationship between voltage and current is greatly deviated from the target phase position. In this case, the two light emitting diodes (light emitting diodes LED 1 and 2 or light emitting diodes LED 3 and 4) of the phase detecting means are turned on and the phase detection signal emits two optical signals, and the motor control circuit 3b In response to the phase detection signal, the motor is controlled to rotate at high speed clockwise (CW direction) or counterclockwise (CCW direction). The direction of rotation of the motor is determined by which light emitting diode is lit.
[0053]
FIGS. 3B and 3D show a case where the phase relationship between the voltage and current is small from the target phase position. In this case, one light-emitting diode (light-emitting diode LED1 or light-emitting diode LED3) of the phase detection means is turned on and the phase detection signal emits one optical signal, and the motor control circuit 3b outputs this phase detection signal. In response, the motor is controlled to rotate at a low speed clockwise (CW direction) or counterclockwise (CCW direction).
[0054]
The direction of rotation of the motor is determined by which light emitting diode is lit. In this example, when the light emitting diodes LED1 and 2 emit light, the motor is rotated clockwise (CW direction), and when the light emitting diodes LED3 and 4 emit light, the motor is rotated counterclockwise (CCW direction). ing.
[0055]
Next, an operation example using the high-frequency power source of the present invention will be described. FIG. 4 is a diagram for explaining an example of the operation of the motor based on the phase detection signal. Here, it is assumed that the voltage and current initially have a phase shift as indicated by a one-dot chain line a in FIG. In a state where the amount of this phase shift is large (state indicated by A in the figure), as shown in FIG. 4B, the phase detection means turns on the LEDs 1 and 2 and outputs a phase detection signal. As shown in FIG. 4C, the motor rotates at a high speed in a predetermined direction (for example, the CW direction) in response to the phase detection signal due to this lighting, drives the variable capacitor of the matching box at a high speed, and performs impedance matching. Perform the action.
[0056]
In this impedance matching operation, a phase shift as shown by c in FIG. 4 (a) is formed to compensate for the phase shift a, which is inherent, and the phase shift is performed as shown by b in FIG. 4 (a). Is reduced (state indicated by B in the figure).
[0057]
When the amount of phase shift is reduced by this operation (in the state indicated by B in the figure), as shown in FIG. 4B, the phase detection means turns on only LED 1 and outputs a phase detection signal. As shown in FIG. 4 (c), the motor rotates at a low speed in a predetermined direction (for example, CW direction) in response to the phase detection signal due to this lighting, drives the variable capacitor of the matching box at a low speed, and performs impedance matching. Perform the action.
[0058]
By this impedance matching operation, the phase shift amount is reduced toward zero as shown in the state indicated by the stage C in the figure.
[0059]
Thus, hunting in the vicinity of the target phase position can be prevented by adjusting the phase at a high speed when the phase shift is large and adjusting the phase at a low speed when the phase shift is small.
[0060]
Next, another operation example by the high-frequency power source of the present invention will be described with reference to FIG. In this operation example, the target phase position is set according to the purpose. For example, when the amount of phase shift in the stable state of the plasma is known in advance, the target phase position is set in advance in accordance with the amount of shift, and the phase of the phase detection signal is zero when the plasma is stable. It can be applied to control to be.
[0061]
When the characteristics of the phase shift after the plasma is turned on are known, for example, as indicated by the one-dot chain line d in FIG. 5A, the phase shift is set in the opposite direction in advance based on the phase shift amount. A broken line e in FIG. 5A indicates a phase shift set in advance. The phase shift can be set by forcibly rotating the motor 3a by the motor control circuit 3b.
[0062]
After the time point when the plasma is turned on (time point D in FIG. 5A), the phase shift converges toward the target phase position as shown by the solid line in FIG. This change in phase position is obtained by combining a preset phase shift (broken line e) and a phase shift characteristic after the plasma is turned on (dashed line d).
[0063]
This phase position can be confirmed by the lighting state of the light emitting diode shown in FIG. 5 (b). At the time before the plasma lighting time D, the light emitting diode (for example, LED3) is turned on by a preset phase shift. When the phase shift is eliminated after the plasma is turned on, the light emitting diode (for example, LED 3) is turned off. It can be confirmed that the phase shift is adjusted by turning off the light emitting diode.
[0064]
In the above example, the phase shift is set in advance, but a mode in which the phase shift is not set may be employed. In this case, the same phase adjustment operation can be performed by obtaining the lighting state of the light emitting diode with respect to the known phase shift and the adjustment amount of the phase shift in this lighting state.
[0065]
In the above description, an example in which the number of light emitting elements such as light emitting diodes is four is described, but the number of light emitting elements is not limited to four and can be arbitrarily set.
[0066]
According to the aspect of the present invention, the phase detection signal is transmitted as an optical signal through an optical fiber, so that no influence is exerted on other control circuits except for high-frequency noise transmitted through the transmission path without providing a new power cable. Can be prevented.
[0067]
According to the aspect of the present invention, the rotational speed of the motor can be changed according to the magnitude of the phase shift by setting the phase detection signal as a digital value and setting the rotational speed of the motor in accordance with the digital value. It is possible to prevent hunting of the motor near the target phase position.
[0068]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a high-frequency power source that is less susceptible to noise and an ICP emission spectroscopic analysis device high-frequency power source.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a high-frequency power source and an ICP emission spectroscopic analyzer of the present invention.
FIG. 2 is a circuit diagram for explaining a configuration example of phase detection means provided in the high-frequency power supply according to the present invention.
FIG. 3 is a relationship diagram for explaining a relationship between a lighting state of a light emitting diode and a motor operation.
FIG. 4 is a diagram for explaining an operation example of a motor by a phase detection signal of the present invention.
FIG. 5 is a diagram for explaining another operation example by the high-frequency power supply according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... High frequency power supply, 2 ... Torch, 3 ... Matching box, 3a ... Motor, 3b ... Motor control circuit, 4 ... Phase detection means, 5 ... High frequency power line, 6 ... Rogowski coil, 7 ... Control board, 8 ... Optical fiber DESCRIPTION OF SYMBOLS 9 ... Control circuit 10 ... ICP emission-spectral-analysis apparatus, 11 ... Plasma, 12 ... Plasma light emission part, 13 ... Spectroscopy / photometry part, 14 ... Recording / display part.

Claims (4)

A matching box having a variable capacitor, matching the impedance between the high-frequency power line and the load and supplying high-frequency power to the load, and detecting the phase of the high-frequency voltage and current supplied to the matching box Phase detection means for outputting as a signal;
A high-frequency power source comprising: adjusting means for adjusting a capacity of a variable capacitor of the matching box based on the optical signal. The phase detection means detects a distance between the detected phase position and a target phase position by a digital value based on the number of lighting of a plurality of light emitting elements,
The high-frequency power supply according to claim 1, wherein the adjusting unit adjusts the phase adjustment speed by changing a speed of adjusting the variable capacitor capacity according to a digital value. The phase detection means includes
A variable resistor is connected in series to each of the light emitting elements, and the detection sensitivity of each light emitting element is variable by changing the resistance value of the variable resistor,
The high frequency power supply according to claim 2, wherein one resistor is connected in parallel to each of the light emitting elements, and a zero point of the phase detection signal is made variable by adjusting a zero potential position of the resistor. . A plasma light emitting unit including the high frequency power source according to any one of claims 1 to 3, and a spectroscopic / photometric unit,
The ICP emission spectroscopic analysis apparatus, wherein the high-frequency power supply supplies high-frequency power to a plasma light-emitting unit.

Images