JPH03144331A - Cold cathode vacuum gage - Google Patents

Abstract

PURPOSE:To ensure detection of detachment and discontinuity of a cable from a cold cathode vacuum gage and also to enable checkup of operations of the whole by a method wherein a closed loop circuit is made up in a state wherein a contact electrode is brought into contact with a central electrode, and a thin conductor having a detecting terminal in the outer end is connected to the central electrode. CONSTITUTION:In order to check up an oblivion of connection of a cable after the repair of a vacuum apparatus, periodical maintenance thereof or the like is conducted, a cold cathode vacuum gage 21 is held in a state of operation and a permanent magnet 14 is moved from a regular position and pulled out. A magnetic field generated by the magnet 14 is eliminated in this way, and a curve is made to be caused in a contact electrode 22 by its own elastic force and thereby it is brought into contact with a central electrode 11. Thereby a current from a high-tension power source 25 is made to flow through the electrodes 22 and 11 and a vacuum flange 13, and by detecting this current by a comparator 28, it is known without fail that a coaxial cable 24 is in contact with a high-tension connection connector 15 of the vacuum gage 21. When a thin conductor 41 having a connection detecting terminal 42 in the outer end is connected beforehand to be central electrode 11, it is also possible to measure a voltage impressed on the electrode 11.

Description

[Detailed Description of the Invention] [Summary] Regarding cold cathode vacuum gauges, detects accidents such as cable disconnection and disconnection of cold cathode vacuum gauges,
The purpose is to provide a cold cathode vacuum gauge that can improve the integrity of the vacuum system, and has a center electrode and an outer electrode in the connecting flange, and a permanent magnet placed outside the outer electrode allows these to be connected. In a cold cathode vacuum gauge that detects the degree of vacuum based on the discharge current generated between the center electrode and the outer electrode due to the cold cathode discharge phenomenon when a magnetic field is generated between each electrode and a high voltage is applied to the center electrode. , a contact electrode made of a magnetic material responsive to a magnetic field and having elasticity is provided inside the connection flange, and the contact electrode is arranged inside the connection flange opposite to the center electrode,
When the permanent magnet is placed in the normal position, it reacts to the magnetic field and contacts the inner surface of the connection flange, and when the permanent magnet is moved from the normal position, it stops responding to the magnetic field and contacts the center electrode due to elastic force. Configure it to do so.

In addition, it has a center electrode and an outer electrode, and a permanent magnet placed outside the outer electrode generates a magnetic field between these electrodes, and when a high voltage is applied to the center electrode, the center In a cold cathode vacuum gauge that detects the degree of vacuum based on a discharge current generated between an electrode and an external electrode, a thin conducting wire is connected to the center electrode, and a connection detection terminal is provided at the other end of the conducting wire. do.

[Industrial application field]

The present invention relates to a cold cathode vacuum gauge, and more particularly to a cold cathode vacuum gauge provided with means for detecting whether a sensor section and a control section cable are securely connected.

Demand for equipment that uses vacuum to manufacture semiconductor thin films, insulating thin films, etc. is increasing year by year, and higher vacuum performance is also required. Vacuum gauges used to measure the degree of vacuum in these devices include vacuum gauges and cold cathode vacuum gauges, but these gauges are used in areas that are frequently exposed to the atmosphere or where vacuum breakage accidents may occur. A cold cathode vacuum gauge, which does not have a red-hot filament, is better for this purpose.

However, the cold cathode vacuum gauge is a two-electrode type that applies a voltage of 3 to 5 kV and measures the discharge current proportional to the degree of vacuum. If the specified voltage is not applied to the probe due to disconnection or disconnection, no discharge will occur, and both will be measured as ultra-high vacuum below the measurement limit, making it impossible to distinguish between the three conditions. Vacuum gauges have a filament and thermionic collector electrode in the vacuum probe, so if you monitor the filament current and thermionic current on the vacuum gauge controller side, you can easily detect abnormalities in the control circuit, probe, or connection cable. However, cold cathode vacuum gauges have no means of detecting these abnormalities.

[Conventional technology]

As a conventional cold cathode vacuum gauge, for example, the one shown in FIG. 7.8 is known, and this is applied to an SOR device. Figure 7 is a schematic configuration diagram of the SOR device. In this figure, l is the main body of the device for generating SOR light as an intense X-ray source, 2 is a passage for extracting the SOR light, and 3 is the SOR light made of beryllium. window, 4
5 is a cold cathode vacuum gauge that detects the degree of vacuum in passage 2; 6 is a controller; and 7 is a driver that drives high-speed shut-off valve 4. be.

During operation of the device main body 1, the vacuum inside the passage 2 is maintained by the cold cathode vacuum gauge 5.
When a decrease in the degree of vacuum is detected (for example, due to the breakage of the take-out window 3), a control signal is generated in the controller 6, and the driver 7 drives the high-speed shutoff valve 4 to close the passage 2 and close the passage 2. The vacuum of the body 1 is protected.

Here, the structure of the cold cathode vacuum gauge 5 is shown as shown in FIGS. 8(a) and 8(b). Note that FIG. 8(b) is a view of the cold cathode vacuum gauge 5 shown in FIG. 8(a) as viewed from the direction of arrow A near the center. As shown in FIGS. 8(a) and 8(b), the cold cathode vacuum gauge 5 includes an insulated center electrode 11 and a plurality of grounded perforated disks arranged at certain intervals around the center electrode 11. The outer electrode 12 is the main electrode structure, and a high voltage of 3 to 5 kV is applied to the center electrode 11 via a coaxial cable, and a discharge current proportional to the degree of vacuum between the center electrode 11 and the outer electrode 12 is measured. This allows the degree of vacuum to be detected. In addition, 13 is a connection flange, 14 is a permanent magnet that applies a parallel magnetic field to the center electrode 11, 15 is a high voltage connection connector, and 16 is an insulating member.

(Problem to be solved by the invention) However, with such conventional cold cathode vacuum gauges, the controller always sees them as open, so even if there is an accident such as a disconnection or disconnection of a cable, it cannot be detected. First, there was a problem in that the reliability of a vacuum system using a cold cathode vacuum gauge decreased.

That is, the inside of the passage is maintained at an ultra-high vacuum of 10-9 to 1 O-10 torr, and in such an ultra-high vacuum, the discharge current between the electrodes has a value of about nA-pA. Therefore, not only is it very difficult to detect the discharge current, but also
In ultra-high vacuum, the discharge cannot be maintained and may stop. However, if the discharge stops in an ultra-high vacuum, there is no problem with the system, because if the degree of vacuum in the vacuum system falls within the measurement range of the vacuum gauge,
This is because it immediately starts discharging and operates normally. Failure to apply a normal voltage to the measurement electrodes may be due to a malfunction in the high voltage generator in the measurement control system, but the operation of these cases can be confirmed by providing a high voltage detection circuit on the control circuit. The problem is when the normal voltage is not being applied to the measurement electrode due to a disconnected cable or a cross section of the cable, and the cable of the measurement electrode is often disconnected when repairing a vacuum equipment failure or during regular maintenance. Connections are often forgotten when returning after inspection.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cold cathode vacuum gauge that can detect accidents such as cable disconnection or disconnection of the cold cathode vacuum gauge and improve the reliability of the vacuum system.

[Means to solve the problem]

In order to achieve the above object, the cold cathode vacuum gauge according to the invention as claimed in claim 1 has a center electrode and an outer electrode in the connecting flange, and a permanent magnet placed outside the outer electrode creates a magnetic field between these electrodes. In a cold cathode vacuum gauge that detects the degree of vacuum based on a discharge current generated between a center electrode and an external electrode due to a cold cathode discharge phenomenon when a high voltage is applied to the center electrode, is provided with a contact electrode made of a magnetic material responsive to a magnetic field and having elasticity, the contact electrode being disposed inside the connecting flange facing the center electrode, and disposing the permanent magnet in a regular position. When the permanent magnet is moved from its normal position, it contacts the inner surface of the connecting flange in response to a magnetic field, and when the permanent magnet is moved from its normal position, it stops responding to the magnetic field and contacts the center electrode by elastic force.

Further, the cold cathode vacuum gauge according to claim 2 has a center electrode and an outer electrode, and a permanent magnet placed outside the outer electrode generates a magnetic field between each of these electrodes, and a high voltage is applied to the center electrode. In a cold cathode vacuum gauge that detects the degree of vacuum based on the discharge current generated between the center electrode and the outer electrode due to the cold cathode discharge phenomenon when R is applied, a thin conducting wire is connected to the center electrode, and the A connection detection terminal is provided at the other end.

[Effect]

In the invention according to claim 1, the contact electrode is arranged inside the connection flange facing the center electrode, and when the permanent magnet is placed in a normal position, it contacts the inner surface of the connection flange in response to a magnetic field, and the permanent magnet When moved from its normal position, it stops responding to the magnetic field and contacts the center electrode due to its elastic force.

Therefore, the state in which the contact electrode is in contact with the center electrode becomes a closed loop circuit, and by passing a current from the outside, accidents such as disconnection or disconnection of the cable to the cold cathode vacuum gauge can be reliably detected.

Further, in the invention according to claim 2, a thin conductive wire is connected to the center electrode, and a connection detection terminal is provided at the other end of the conductor, so that a voltmeter is connected to the connection detection terminal and the voltage is applied to the center electrode. The operation of the entire vacuum gauge can be confirmed by directly measuring the voltage at the terminal or by grounding the terminal through a resistor.

Therefore, accidents such as cable disconnection and disconnection can be detected similarly to the invention described in claim 1.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

1 to 3 are diagrams showing a first embodiment of a cold cathode vacuum gauge according to the invention as claimed in claim 1, and this embodiment, like the conventional example, uses the present invention for detecting a decrease in the degree of vacuum in an SOR device. This is an example applied to

FIG. 1 <a> is a cross-sectional configuration diagram of the cold cathode vacuum gauge 21, and FIG. 1(b) shows the cold cathode vacuum gauge 21 shown in FIG.
FIG. 2 is a view of the vicinity of the center viewed from the direction, and in these drawings, the same components as in the conventional example are given the same reference numerals and redundant explanations will be omitted.

A rod-shaped contact electrode 22 is provided inside the connecting vacuum flange 13, and the contact electrode 22 is made of a ferromagnetic material such as iron and has elasticity.One end of the contact electrode 22 is fixed to the inner wall of the connecting vacuum flange 13. , the other end is a movable free end. 23 is an external electrode, and a notch 23a is formed in a part of the external electrode 23, so that the movement of the contact electrode 22 is not hindered. The contact electrode 22 is a permanent magnet 1
4 is placed in the normal position (the position shown in FIG. 1(a)), it contacts the inner surface of the connecting vacuum flange 13 in response to the magnetic field created by the permanent magnet 14, and moves the permanent magnet 14 from the normal position. When pulled out from the connecting vacuum flange 13, the structure is such that it stops responding to the magnetic field and contacts the center electrode 11 by elastic force.

The cold cathode vacuum gauge 21 is connected to the coaxial cable 2 as shown in FIG.
4 to a high voltage power supply 25, and the center electrode 11 receives a high DC voltage (for example, 3 to 5 kV) from the high voltage electrode 25.
is supplied. Further, the external electrode 23 is grounded together with the connecting vacuum flange 13. When a high voltage is applied to the center electrode 11, a discharge current corresponding to the degree of vacuum is generated between the center electrode 11 and the outer electrode 23 due to a cold cathode discharge phenomenon.
This discharge current is taken out as a voltage drop across the resistor 26, amplified by an amplifier 27, and input to a comparator 28. The comparator 28 compares the output of the amplifier 27 with a reference voltage Vr corresponding to the reference vacuum degree, and when the vacuum degree of the passage 2 exceeds the reference vacuum degree, it outputs a signal to close the high-speed shutoff valve 4, for example. Output to driver 7.

In the above configuration, after repairing the vacuum equipment when it breaks down or performing periodic maintenance, the cold cathode vacuum gauge 21 is operated to confirm whether a cable has been forgotten or not (see Fig. 1(a)). From the state shown in FIG. 2(b)), the permanent magnet 14 is moved from its normal position and removed as shown in FIGS. 2(a) and 2(b). Then, the magnetic field generated by the permanent magnet 14 disappears, so that the contact electrode 22 bends due to its own elastic force and contacts the center electrode 11. Therefore, current from the high-voltage power supply 25 connects to the center electrode 11 via the contact electrode 22 to the vacuum flange 1.
3, which is detected by the output of comparator 28. This makes it possible to confirm that the coaxial cable 24 is reliably connected to the high voltage connector 15 of the cold cathode vacuum gauge 21 and that there is no accident such as disconnection of the cable. Furthermore, in this embodiment, in addition to a cable accident, the high voltage circuit current is not measured in the case of an abnormality in the high voltage circuit including the high voltage power supply 25 or an abnormality in the discharge current detection circuit including the resistor 26, so such abnormalities can be detected. can do. As a result, the reliability of the vacuum system can be significantly improved.

Next, FIGS. 4(a) and 4(b) show the second aspect of the invention according to claim 1.
It is a figure showing an example, and this example is an example when a small ion pump is used as a vacuum gauge. FIG. 4(a) is a configuration diagram when the permanent magnet 31 is inserted. In this figure, 32 is a vacuum container (corresponding to a connection flange) of a small ion pump, and the vacuum container 32 is shown in FIG. A portion is formed into a cylindrical shape similar to that shown in a). 33 is a cylindrical center electrode to which a high voltage is supplied from the outside via a high voltage terminal 34, 35 is an insulating member that insulates the high voltage terminal 34, and 36 is a contact electrode similar to the first embodiment. .

Therefore, even in this embodiment, when the permanent magnet 31 is moved, the contact electrode 3G comes into contact with the center electrode 33 as shown in FIG. 4(b), and the same effect as in the first embodiment can be obtained. .

Next, FIG. 5 is a diagram showing a first embodiment of the cold cathode vacuum gauge according to the invention of claim 2, and the present invention is of the same type as the first embodiment of the invention of claim 1. This is an example of application to a cold cathode vacuum gauge. FIG. 5 is a cross-sectional diagram of the cold cathode vacuum a1. In this figure, 41 is a thin conducting wire connected to the center electrode 11, 42 is a connection detection terminal provided at the other end of the conducting wire 41, and 43 is a connection terminal. This is an insulating member that insulates the detection terminal 42. The rest is the same as the conventional example and is given the same number.

In this embodiment, for example, a voltmeter is connected to the connection detection terminal 42 while the cold cathode vacuum gauge is in operation, and the voltage applied to the center electrode 11 is directly measured. can be detected and the reliability of the vacuum system can be improved. In addition, as another aspect of the measuring force method, for example, the connection detection terminal 42 may be
By grounding through a resistor of 00 MΩ, a situation similar to that in which a discharge current is flowing can be created, and the above-mentioned accident can be detected.

Next, FIG. 6 (a>(b) is the second
It is a figure showing an example, and is an example applied to a small ion pump vacuum gauge. FIG. 6(a) is a radial cross-sectional view of the vacuum gauge, and FIG. 6(b) is a longitudinal cross-sectional view of the vacuum gauge. In these figures, 45 is a thin conducting wire connected to the center electrode 33; 46 is a connection detection terminal provided on the other end side of the conducting wire 45, and 47 is an insulating member that insulates the connection detection terminal 46. The other parts are similar to the embodiment shown in FIG. 4 and are given the same numbers.

Therefore, in this embodiment as well, accidents such as cable disconnection can be detected by the same method as in the first embodiment shown in FIG. 5, and the same effects can be obtained.

〔Effect of the invention〕

According to the present invention, accidents such as disconnection or disconnection of the cold cathode vacuum 31 cable can be detected, and the reliability of a vacuum system using a cold cathode vacuum gauge can be improved.

[Brief explanation of the drawing]

1 to 3 are diagrams showing a first embodiment of the cold cathode vacuum gauge according to the invention as claimed in claim 1, FIG. 1 is a diagram showing its structure, FIG. 2 is a diagram explaining its operation, FIG. 3 is a diagram showing the control system thereof, FIG. 4 is a diagram showing the structure of a second embodiment of the cold cathode vacuum gauge 1 according to the invention claimed in claim 1, and FIG. f showing the first embodiment of the cold cathode vacuum gauge according to the invention of
6 is a diagram showing the structure of a second embodiment of the cold cathode vacuum i+ according to the invention as claimed in claim 2, FIG. 7 is a main configuration diagram of a conventional SOR device, and FIG. The figure shows the structure of a conventional cold cathode vacuum gauge. 11--Center electrode, 12--External electrode, 13--Connection vacuum flange, 14.31--Permanent magnet, 15--High voltage connection Connector, 1G...Insulating member, 21...Cold cathode vacuum gauge, 22.36...Contact electrode, 23...External electrode, 24... --- Coaxial cable, 25 --- High voltage power supply, 26 --- Resistor, 27 --- Amplifier, 23 --- Comparator, 32 --- - Vacuum container, 33... Center electrode, 34... High voltage terminal, 35.43.47... Insulating member, 41 45-... Conductor, 42. 46...-Connection detection terminal. Figure 1 shows the control system of the first embodiment of the invention as claimed in claim 1. Figure 1 (a) shows the structure of the second embodiment of the invention as claimed in claim 2. ) Figure

Claims (2)

[Claims] (1) Center electrode (11
, 33) and external electrodes (12, 23), and the permanent magnets (14, 31) are arranged outside the external electrodes (12, 23).
) to generate a magnetic field between each of these electrodes, and when a high voltage is applied to the center electrode (11, 33), the center electrode (11, 33) and the outer electrode (12, 23) are connected due to the cold cathode discharge phenomenon. In a cold cathode vacuum gauge that detects the degree of vacuum based on a discharge current generated during , 36), and the contact electrode (22, 36) is connected to the center electrode (11, 3
3), and when the permanent magnet (14, 31) is placed in the normal position, the connecting flange (13, 32) reacts to the magnetic field.
When the permanent magnets (14, 31) are moved from their normal positions, the center electrode (14, 31) stops responding to the magnetic field and is moved by elastic force.
1, 33) A cold cathode vacuum gauge characterized in that it is configured to be in contact with a cold cathode vacuum gauge. (2) Center electrode (11, 33) and outer electrode (12, 23)
) and a permanent magnet (1) placed outside the external electrode (12, 23).
4, 31) to generate a magnetic field between each of these electrodes, and when a high voltage is applied to the center electrode (11, 33), the center electrode (11, 33) and the outer electrodes (12, 33) are connected due to the cold cathode discharge phenomenon. 23) In a cold cathode vacuum gauge that detects the degree of vacuum based on the discharge current generated between
and connect the connection detection terminals (42, 45) to the other ends of the conductors (41, 45).
46) A cold cathode vacuum gauge characterized by being provided with.