JP2014048264A - Cold-cathode ionization gauge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold-cathode ionization gauge that prolongs lifetimes of a discharge induction member and an anode by suppressing sticking of a product material due to a discharge between the discharge induction member and a tip part of the anode and also suppressing consumption.SOLUTION: A cold-cathode ionization gauge including a cylindrical cathode 101, a rod-like anode 102 arranged in an internal space of the cylindrical cathode 101, magnetic means 103a, 103b of generating a discharge between the anode and the cathode by producing a magnetic field substantially orthogonal to an electric field between the anode and the cathode, and a discharge induction member 105 arranged in the cathode, includes a shield plate 2 which partitions the internal space of the cathode 101 into one space A2 in which a tip part of the anode 102 and the discharge induction member 105 are arranged and the other space A1.

Description

  The present invention relates to a cold cathode ionization vacuum gauge, and more particularly, to an internal space of a cathode, a space in which a tip portion of an anode and a discharge inducing member are arranged, and another space in which the tip portion of the anode and the discharge inducing member are not arranged. It relates to the cold cathode ionization vacuum gauge.

  The inventors of the present application have conducted extensive research on cold cathode ionization vacuum gauges, and for example, as shown in Patent Document 1, a cold cathode ionization vacuum gauge capable of easily mounting and replacing a discharge inducing member is disclosed. is suggesting.

The cold cathode ionization vacuum gauge provided with the discharge inducing member shown in Patent Document 1 will be described with reference to FIG.
The cold cathode ionization vacuum gauge 100 includes a cylindrical cathode 101 having an opening at one end, and a rod-shaped anode 102 disposed in the internal space of the cylindrical cathode 101. In addition, magnetic means (magnets 103 a and 103 b) is provided that forms a magnetic field substantially orthogonal to the electric field between the anode 102 and the cathode 101 and causes discharge between the anode 102 and the cathode 101.

A pole piece 104 that maintains a discharge state is fitted to the opening edge of the cylindrical cathode 101, and the opening is covered by the pole piece 104.
A screw 105 as a discharge inducing member is detachably screwed to the pole piece 104. The head of the screw 105 is disposed so as to face the tip of the anode 102 disposed in the internal space of the cathode 101.

The pole piece 104 has a disk shape, and a screw hole 104a is formed in an axial center portion of the pole piece 104, and the screw 105 is screwed into the screw hole 104a.
The pole piece 104 includes a plurality of through holes 104b arranged around a screw 105 screwed into the shaft center portion. The through holes 104b are provided for smooth exhaust characteristics from atmospheric pressure, and the number thereof is designed as appropriate.

  One end of the anode 102 is attached to the connector 106 and is electrically connected to the connector 106. The other end (tip portion) of the anode 102 is inserted through a through-hole 101a1 formed in the bottom 101a of the cathode 101 through a feedthrough (current introduction terminal) 107, and is arranged in a space in the cylinder of the cathode 101. The

  The anode 102 and the cathode 101 are disposed in the enclosure 108. Further, the enclosure 108 is provided with a flange 109 and a Pirani vacuum gauge 110 as an auxiliary pressure sensor attached to the flange 109. In FIG. 1, reference numeral 109a denotes a screw for fixing the flange 109.

The connector 106 is electrically connected to the connector 112b via the circuit boards 111c, 111b, and 111a. Further, although not shown, the connector 112b is connected to a power source that applies a voltage to the anode 102.
Furthermore, the enclosure 108 is connected to the substrate 111c via the cathode plate 113 and grounded. The circuit boards 111 a, 111 b, and 111 c are held by the board holding member 114 and accommodated in the case 115.

  In addition to the connector 112b, the back surface of the case 2 is provided with a switch 112a and an LED 112c for displaying on / off of the power source. Further, reference numeral 116 in the figure denotes a connector for connecting the circuit boards 111a and 111b, and reference numeral 117 denotes a connector for connecting the circuit boards 111b and 111c.

Since the head of the screw 105 screwed to the pole piece 104 in this manner is disposed opposite to the tip of the anode 102 disposed in the internal space of the cathode 101, the head of the screw 105 and the anode Discharge is likely to occur between the tip of 102 and the time lag between the time when a high voltage is applied to the cold cathode ionization vacuum gauge 100 and the time when the current starts to flow after discharging becomes small. Measurement can be performed efficiently.
Further, since the screw 105 (discharge inducing member) is attached to the pole piece 104 that is detachably fitted to the opening edge of the cathode, the screw 105 (discharge inducing member) is consumed due to the oxidizing action of ions in the plasma. Even in this case, a new screw 105 (discharge inducing member) can be easily replaced.

JP 2011-27700 A

By the way, the discharge inducing member (screw) and the anode attached to the pole piece are consumed due to the oxidizing action of ions in the plasma generated in the internal space (discharge space) of the cathode when used for a long time.
Further, in the internal space of the cathode, products such as oxides and nitrides other than ions caused by plasma are generated and adhere to the discharge inducing member and the anode, and the discharge inducing function is deteriorated.
In this way, when the discharge inducing member and the anode are deteriorated due to wear and adhesion, the above-described discharge inducing member and anode are cleaned and replaced.
However, frequent cleaning work is not preferable in terms of work efficiency, and although the discharge inducing member and the anode can be replaced, frequently performing these replacement work results in work efficiency and a cold cathode ionization vacuum gauge. It was not preferable in terms of maintenance cost.

  The present invention has been made to solve the above technical problem, and suppresses the adhesion of the product due to the discharge of the discharge inducing member and the tip of the anode, and also suppresses the consumption of the discharge inducing member and the anode tip. Another object of the present invention is to provide a cold cathode ionization vacuum gauge that extends the life of the discharge inducing member and the anode.

  In order to achieve the above object, a cold cathode ionization vacuum gauge according to the present invention includes a cylindrical cathode, a rod-shaped anode disposed in an internal space of the cylindrical cathode, and an electric field between the anode and the cathode. In a cold cathode ionization vacuum gauge comprising a magnetic means for forming a magnetic field substantially perpendicular to the cathode and causing a discharge between the anode and the cathode, and a discharge inducing member disposed in the cathode, the internal space of the cathode And a shielding plate that divides the anode into a space in which the tip of the anode and the discharge inducing member are disposed and another space in which the tip of the anode and the discharge inducing member are not disposed. It is said.

In this way, the internal space of the cathode is divided into one space in which the tip portion of the anode and the discharge inducing member are arranged and another space in which the tip portion of the anode and the discharge inducing member are not arranged. Separated by.
As a result, the tip of the anode and the discharge inducing member are shielded from ions caused by plasma generated in other spaces, and consumption due to the oxidizing action of the ions is suppressed.
In addition, even for products such as oxides and nitrides other than ions due to plasma, the shielding plate suppresses intrusion from another space into one space, so that oxidation to the tip of the anode and the discharge inducing member is performed. The adhesion of products such as products and nitrides is also suppressed.
As described above, since contamination due to the adhesion of the product and exhaustion due to the oxidation of ions can be suppressed, the number of times of cleaning and replacing the discharge inducing member and the anode can be reduced. That is, it is possible to obtain a cold cathode ionization vacuum gauge capable of extending the life of the discharge inducing member and the anode.
In addition, this cold cathode ionization vacuum gauge is preferable from the viewpoint of work efficiency and maintenance cost because it is not necessary to frequently perform cleaning work and replacement work.

Here, the shielding plate is formed in a bottomed cylindrical shape, and the bottom surface portion of the shielding plate has the same diameter as that of the internal space of the cylindrical cathode, It is desirable that a through hole through which the anode is inserted is formed.
With such a shielding plate, the shielding plate can be easily attached by fitting it in the internal space of the cylindrical cathode, and can be easily divided into the one space and the other space. .

Further, the shielding plate is a plate-like substrate having the same diameter as the inner space of the cylindrical cathode, a through hole formed in the center of the plate-like substrate, through which the anode is inserted, It is desirable to have a side wall that is provided at both ends of the base and that extends outward in the radial direction.
With such a shielding plate, since the radially outward side walls provided at both ends of the base are pressed against the inner wall of the cylindrical cathode, the shielding plate can be easily attached to the internal space of the cathode. it can.

Also, a pole piece attached to the opening edge of the cylindrical cathode, and one space in which the tip end portion of the anode and the discharge inducing member are arranged and another space attached to the pole piece A shielding plate that is divided into a bottom surface portion having a diameter smaller than the diameter of the internal space of the cathode, and a through hole that is formed in the center portion of the bottom surface portion and through which the anode is inserted, A side wall portion formed on the periphery of the bottom surface portion; an arm portion extending upward from an upper end portion of the side wall portion of the shielding plate; and a locking portion formed on an end portion of the arm portion. It is desirable that the shielding plate is attached to the pole piece by locking the locking portion to the pole piece.
In this way, since the shielding plate is attached to the pole piece, the shielding plate can be replaced simultaneously with the replacement of the pole piece. Even when the pole piece is not replaced, the locking portion can be easily removed from the pole piece. It can be removed, and the replacement work of the shielding plate can be performed efficiently.

Moreover, it is desirable that the shielding plate includes a bottom surface portion having a through-hole through which the anode formed in a central portion is inserted, and a protrusion formed to protrude into the through-hole.
Thus, when the protrusion is formed in the through hole of the shielding plate, the protrusion functions as a discharge inducing member.
Therefore, in the internal space of the cathode, one space where the tip and the protrusion of the anode are arranged is separated from the other space by the shielding plate (bottom surface). As a result, the tip and protrusion of the anode are shielded from ions caused by plasma generated in other spaces, and consumption of the tip and protrusion of the anode is suppressed.
In addition, even for products such as oxides and nitrides other than ions due to plasma, intrusion into the one space from another space is suppressed, so that the product adheres to the tip and protrusions of the anode. It is suppressed.

Here, when the shielding plate is attached to the cylindrical cathode, the projection is bent so that the tip of the projection faces the opening direction of the cylindrical cathode, and the tip of the projection and the tip of the anode Is preferably covered with a shielding plate and shielded from other spaces.
In this manner, the protrusion can be disposed in one space partitioned by the shielding plate (bottom surface) by bending the protrusion in the opening direction of the internal space of the cathode.

  According to the present invention, it is possible to suppress the adhesion of the product due to the discharge of the discharge inducing member and the tip of the anode, and to suppress the consumption of the discharge inducing member and the tip of the anode, thereby extending the life of the discharge inducing member and the anode. A cathode ionization gauge can be obtained.

FIG. 1 is a cross-sectional view of a main part of a cold cathode ionization vacuum gauge according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a shielding plate used in the first embodiment shown in FIG. FIG. 3 is a cross-sectional view of an essential part showing an assembly procedure of the first embodiment shown in FIG. FIG. 4 is a perspective view showing another shielding plate. FIG. 5 is a cross-sectional view of a principal part of a cold cathode ionization vacuum gauge according to the second embodiment of the present invention. 6 is a cross-sectional view taken along the line II shown in FIG. FIG. 7 is a side view showing a shielding plate used in the second embodiment shown in FIG. FIG. 8 is a cross-sectional view of a main part of a cold cathode ionization vacuum gauge according to the third embodiment of the present invention. FIG. 9 is a view as seen from the direction of the arrow shown in FIG. FIG. 10 is a perspective view showing a shielding plate used in the third embodiment shown in FIG. FIG. 11 is a cross-sectional view of an essential part showing a conventional cold cathode ionization vacuum gauge.

  A first embodiment of a cold cathode ionization vacuum gauge according to the present invention will be described with reference to FIGS. 1 to 4, the same or corresponding members as those shown in FIG. 11 are denoted by the same reference numerals, and detailed description thereof is omitted. 1 and 3, only the configuration particularly related to the present invention is shown in the configuration of the cold cathode ionization vacuum gauge shown in FIG. 11, and the other configurations are not shown.

The cold cathode ionization vacuum gauge according to the present invention includes an internal space A of a cylindrical cathode 101, an internal space A2 in which a tip 105 of the anode 102 and a screw 105 as a discharge inducing member are disposed, and another internal space A1. It is characterized by having a shielding plate 2 that is divided into two.
The tip of the anode 102 and the screw 105 are shielded from ions by plasma generated in the other internal space A1 by the shielding plate 2, and the consumption of the anode 102 and the screw 105 due to the oxidation of ions is suppressed.
Further, since the shielding plate 2 prevents the product generated in the other internal space A1 from entering the internal space A2, the product adheres to the tip of the anode 102 and the screw 105 that is the discharge inducing member. It is suppressed.

  As shown in FIG. 2, the shielding plate 2 is formed in a bottomed cylindrical shape, and has a bottom surface portion 2 a having the same diameter as the inner space A of the cylindrical cathode 101. A through hole 2a1 through which the rod-shaped anode 102 is inserted is formed at the center of the bottom surface 2a. Further, a side wall portion 2b is formed perpendicular to the bottom surface portion 2a in the peripheral portion of the bottom surface portion 2a.

  The shielding plate 2 is made of a material such as stainless steel (for example, SUS304) and has a thickness of 0.2 mm to 0.5 mm. When the plate thickness is less than 0.2 mm, the mechanical strength is weak, and when the plate thickness exceeds 0.5 mm, the cold cathode discharge itself is affected.

When the difference between the diameter of the through-hole 2a1 and the diameter of the anode 102 is large, ions caused by the plasma generated in the internal space A1 enter the internal space A2 from the internal space A1 and suppress the consumption due to the oxidation action by the ions This is not preferable because the effect of reducing the effect is reduced.
Therefore, it is preferable that the difference between the diameter of the through hole 2a1 and the diameter of the anode 102 is small. However, if the diameter is too small, it is difficult to insert the anode 102 into the through hole 2a1.
Therefore, the diameter of the rod-shaped anode 102 is generally 1.4 mm to 1.5 mm, and the diameter of the through hole 2a1 is 2 to 4 times the diameter when the diameter of the rod-shaped anode 102 is 1. Is preferably formed.

As shown in FIG. 3, the shielding plate 2 is accommodated in the internal space A of the cathode 101 from the opening side of the cylindrical cathode 101.
At this time, the bottom surface portion 2a of the shielding plate 2 has the same diameter as the diameter of the internal space A of the cathode 101, and the side wall portion 2b is formed perpendicular to the bottom surface portion 2a1. The shielding plate 2 is fitted and stored on the inner peripheral surface of the cylindrical cathode 101.
As shown in FIG. 1, the tip of the anode 102 is inserted through the through hole 2 a 1 of the shielding plate 2, and the tip of the anode 102 and the screw 105 that is a discharge inducing member are arranged by the shielding plate 2. It is divided (separated) into an internal space A2 and another internal space A1.

  Further, a pole piece 104 that maintains a discharge state is fitted to the opening edge of the cylindrical cathode 101, and the opening of the cathode 101 is covered by the pole piece 104. The pole piece 104 is detachably screwed with a screw 105 of a discharge inducing member.

Thus, in the state where the pole piece 104 is attached to the opening edge of the cylindrical cathode 101, the head of the screw 105 is disposed opposite to the tip of the anode 102, and the screw 105 The head and the tip of the anode 102 are disposed in an internal space A2 of the cylindrical cathode 101 separated by the shielding plate 2.
That is, the head of the screw 105 and the tip of the anode 102 are separated from the other internal space A 1 of the cylindrical cathode 101 by the shielding plate 2.

In particular, by reducing the difference between the diameter of the through-hole 2a1 of the shielding plate 2 and the diameter of the rod-shaped anode and substantially closing the internal space A1, the plasma from the internal space A1 to the internal space A2 via the through-hole 2a1. It restricts the intrusion of ions.
As described above, since the intrusion of ions by plasma into the internal space A2 is suppressed, the tip of the anode 102 and the discharge inducing member (screw 105) are suppressed from being consumed by the oxidizing action of the plasma ions.

  Similarly, since the intrusion of products such as oxides and nitrides into the internal space A2 is also suppressed, the generation of oxides, nitrides and the like on the tip portion of the anode 102 and the discharge inducing member (screw 105). The adhesion of objects is also suppressed.

Thus, the shield plate 2 shields the screw 105 and the tip of the anode 102 from the internal space A1 (discharge space) and protects them from the oxidization of ions by the plasma formed in the internal space A1 (discharge space). Further, it is protected from the adhesion of products such as oxides and nitrides generated by the plasma formed in the internal space A1 (discharge space).
Thereby, the lifetime of the screw 105 and the tip of the anode 102 can be extended, and the number of cleaning operations and replacement operations can be reduced.

In addition, in the said embodiment, it was a bottomed cylindrical thing as the shielding board 2, Comprising: The case where the side wall part 2b was provided in the perimeter of the bottom face part 2a was demonstrated.
However, the shielding plate is not limited to the shielding plate 2, and as shown in FIG. 4, the plate-like base 3 a and the arc-shaped side wall portions provided on both sides of the base 3 a in plan view. You may use the shielding board 3 which has 3b.
In this case, the side wall 3b extends from the vertical direction to the radially outer side with respect to the base body 3a (in FIG. 4, the angle θ extends from the vertical direction and expands radially outward).
When the side wall 3 b is extended and extended radially outward in this way, the side wall 3 b is pressed against the inner wall of the cathode 101 when the shielding plate 3 is accommodated in the internal space of the cathode 101. Therefore, it can be securely fixed.

  Next, a second embodiment according to the present invention will be described with reference to FIGS. Similar to the first embodiment, in FIGS. 5 to 7, the same or corresponding members as those shown in FIG. 11 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 5 shows only the configuration related to the present invention among the configurations of the cold cathode ionization vacuum gauge shown in FIG. 11, and the other configurations are not shown.

  This embodiment is characterized in that the shielding plate 5 is attached to the pole piece 104 when the locking portion 5 d provided on the shielding plate 5 is locked to the upper surface of the pole piece 104. A spring 4 is used instead of the screw 105 as a discharge inducing member.

As shown in FIGS. 5 to 7, the shielding plate 5 has a bottom surface portion 5 a having a diameter smaller than the diameter of the internal space A of the cathode 101. Particularly, as shown in FIGS. 5 and 6, the bottom surface portion 5 a is formed in the same size and shape as a circle in contact with the inside of the four through holes 104 b provided in the pole piece 104.
Further, a through hole 5a1 through which the rod-like anode 102 is inserted is formed at the center of the bottom surface portion 5a. Further, a side wall portion 5b is formed perpendicular to the bottom surface portion 5a on the peripheral portion of the bottom surface portion 5a.

Furthermore, four arm portions 5c provided upward from the upper end portion of the side wall portion 5b of the shielding plate 5 and provided at positions corresponding to the through holes 104b of the pole piece 104, and the end portions of the arm portions 5c A formed locking portion 5d is provided.
The locking portion 4d is formed in a claw shape, and the bottom surface portion 5a is formed in the same size and shape as the circle in contact with the inside of the through hole 104b of the pole piece 104. Passing through 104b, the claw-like locking portion 5d is locked to the upper surface of the pole piece 104.

The shielding plate 2 is made of a material such as stainless steel (for example, SUS304) and has a thickness of 0.2 mm to 0.5 mm.
Further, when the plate thickness is less than 0.2 mm, the mechanical strength is weak, and when the plate thickness exceeds 0.5 mm, the cold cathode discharge itself is affected.

Thus, since the shielding plate 5 is attached to the pole piece 104 attached to the opening edge of the cylindrical cathode 101, the shielding piece 5 is attached by attaching the pole piece 104 to the opening edge of the cylindrical cathode 101. Can be attached to the cold cathode vacuum gauge 10.
The head of the spring 4 is disposed opposite to the tip of the anode 102, and the head of the spring 4 and the tip of the anode 102 are covered with the shielding plate 5, and the internal space A 1 (discharge space) is covered. ).

Therefore, the spring 4 and the tip of the anode 102 are protected from the oxidation of ions by the plasma formed in the internal space A1 (discharge space), and consumption due to the oxidation of ions by the plasma formed in the internal space A1. Can be suppressed.
Similarly, the tips of the spring 4 and the anode 102 are protected from the adhesion of products such as oxides and nitrides generated by the plasma formed in the internal space A1 (discharge space).
Thereby, the lifetime of the spring 4 which is a discharge inducing member and the tip of the anode 102 can be extended, and the number of cleaning operations and replacement operations can be reduced.

Next, a third embodiment according to the present invention will be described with reference to FIGS.
This embodiment is characterized in that a shielding plate having a discharge inducing function is used. As in the first embodiment, in FIGS. 8 to 10, the same or corresponding members as those shown in FIG. 11 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 8 shows only the configuration particularly related to the present invention among the configurations of the cold cathode ionization vacuum gauge shown in FIG. 11, and the other configurations are not shown.

  As shown in FIGS. 8 to 10, the shielding plate 6 has a bottom surface portion 6 a having the same diameter as the diameter of the internal space A of the cathode 101. A through hole 6b through which the rod-like anode 102 is inserted is formed at the center of the bottom surface portion 6a.

Further, as shown in FIG. 9, a protrusion 6c having a pointed tip is formed to protrude into the through hole 6b. The protrusion 6c is a discharge inducing member, and the shielding plate 6 has a discharge inducing function.
The anode 102 is disposed at the center of the through hole 6 b, and a protrusion 6 c is disposed around the outer periphery of the anode 102. This protrusion 6c is bent, and its tip is located on the inner space A2 side. The bending direction of the protruding portion 6 c is bent so that the tip of the protruding portion 6 c faces the opening edge direction of the cylindrical cathode 101 when the shielding plate 6 is attached to the cylindrical cathode.

  A side wall portion 6d is formed on the periphery of the bottom surface portion 6a so as to be perpendicular to the bottom surface portion 6a. Further, a flange 6e is formed in parallel with the bottom surface 6a from the upper end of the side wall 6d of the shielding plate 6. As shown in FIG. 8, the flange 6 e is locked to the opening edge of the cathode 101, so that the shielding plate 6 is attached.

The shielding plate 2 is made of a material such as stainless steel (for example, SUS304) and has a thickness of 0.2 mm to 0.5 mm.
Further, when the plate thickness is less than 0.2 mm, the mechanical strength is weak, and when the plate thickness exceeds 0.5 mm, the cold cathode discharge itself is affected.

  Thus, by attaching the flange portion 6e of the shielding plate 6 to the opening edge of the cylindrical cathode 101, the shielding plate 6 can be attached to the cold cathode vacuum gauge. The tip of the anode 102 is disposed in an internal space A2 that is partitioned by the shielding plate 2.

As described above, since the anode 102 is disposed at the center of the through hole 6b where the protrusion 6c is formed, a discharge is easily generated between the protrusion 6c and the anode 6b, and a cold cathode ionization vacuum is provided. The time delay between the time when the high voltage is applied to the meter and the time when the current starts to flow after discharging is small, and the measurement can be performed efficiently.
Moreover, since the shielding plate 6 has a discharge inducing function, it is not necessary to provide a discharge inducing member as in the first and second embodiments, and can be manufactured at low cost.

  Further, the projection 6c and the tip of the anode 102 are arranged opposite to each other so that the tip of the projection 6c faces the opening direction of the cylindrical cathode when the shielding plate 6 is attached to the cylindrical cathode. Therefore, the tip of the protrusion 6c and the tip of the anode 102 are covered with the shielding plate 6 and shielded from the internal space A1 (discharge space).

Therefore, the protrusion 6c and the tip of the anode 102 are protected from ions by plasma formed in the internal space A1 (discharge space), and the consumption due to the oxidizing action of ions by the plasma formed in the internal space A1 is suppressed. be able to.
Further, the protruding portion 6c and the tip portion 102 of the anode are protected from adhesion of products due to plasma or the like formed in the internal space A1 (discharge space).
As a result, the lifetime of the discharge inducing member (protrusion 6c) and the tip of the anode 102 can be extended, and the number of cleaning operations and replacement operations can be reduced.

2 Shield plate 2a Bottom surface portion 2a1 Through hole 2b Side wall portion 3 Shield plate 3a Base body 3b Side wall portion 4 Spring 5 Shield plate 5a Bottom surface portion 5a1 Through hole 5b Side wall portion 5c Arm portion 5d Locking portion 56 Shield plate 6a Bottom surface portion 6b Through hole 6c Protruding part 6d collar part 101 cathode 102 anode 105 screw (discharge inducing member)
A. Cathode internal space A1 Other space in which the tip of the anode and the discharge inducing member are not arranged A2 One space in which the tip of the discharge inducing member and the anode are arranged

Claims (6)

  A cylindrical cathode, a rod-shaped anode disposed in the inner space of the cylindrical cathode, and a magnetic field substantially perpendicular to the electric field between the anode and the cathode are formed, and a discharge is generated between the anode and the cathode. In a cold cathode ionization vacuum gauge comprising a magnetic means for causing a discharge and a discharge inducing member disposed in the cathode, an internal space of the cathode is defined as one space in which the tip of the anode and the discharge inducing member are disposed. And a shielding plate that separates the tip of the anode and another space in which the discharge inducing member is not disposed.   The shielding plate is formed in a bottomed cylindrical shape, and the bottom surface of the shielding plate has the same diameter as the inner space of the cylindrical cathode, and the anode is inserted into the center of the bottom surface. The cold cathode ionization vacuum gauge according to claim 1, wherein a through hole is formed.   The shielding plate includes a plate-like substrate having the same diameter as the inner space of the cylindrical cathode, a through-hole formed in a central portion of the plate-like substrate, through which the anode is inserted, and the substrate 2. The cold cathode ionization vacuum gauge according to claim 1, further comprising sidewalls that are provided at both end portions of the first and second sidewalls and extend outward in the radial direction. A pole piece attached to the opening edge of the cylindrical cathode;
A shielding plate attached to the pole piece and dividing the internal space of the cathode into one space where the tip of the anode and the discharge inducing member are arranged and another space;
The shielding plate is formed in a bottom surface portion having a diameter smaller than the diameter of the internal space of the cathode, a through hole formed in a central portion of the bottom surface portion and through which the anode is inserted, and a peripheral portion of the bottom surface portion. A side wall portion, an arm portion extending upward from an upper end portion of the side wall portion of the shielding plate, and a locking portion formed at an end portion of the arm portion,
The cold cathode ionization vacuum gauge according to claim 1, wherein the shielding plate is attached to the pole piece by the locking portion being locked to the pole piece.   The said shielding board is provided with the bottom face part which has the through-hole which the said anode formed in the center part penetrates, and the protrusion part formed so that it might protrude in the said through-hole. The cold cathode ionization vacuum gauge according to claim 4.   When the shielding plate is attached to the cylindrical cathode, the projection is bent so that the tip of the projection faces the opening direction of the cylindrical cathode, and the tip of the projection and the tip of the anode are the shielding plate. The cold cathode ionization vacuum gauge according to claim 5, wherein the cold cathode ionization vacuum gauge is covered with and shielded from other spaces.

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