KR100507607B1 - A Vacuum Gauge Using Carbon Nanometer Tubes - Google Patents

Abstract

The present invention relates to a vacuum gauge using carbon nanotubes comprising carbon nanotubes as electrode tips for electron emission for electric field emission, and comprising: a vacuum container having a connection port so that external gas molecules are introduced; A base formed on an inner wall surface of the vacuum container; A carbon tube layer composed of a plurality of carbon nanotubes focused on the base and emitting electrons upon application of a negative voltage; A grid in which a plurality of gates of a corresponding size are passed through the electrons spaced apart from each other on the base to pass the electrons; And a collector arranged at a predetermined interval on the grid and collecting the cations of the gas molecules generated by the collision of electrons.

Description

Vacuum gauge using carbon nanotubes {A Vacuum Gauge Using Carbon Nanometer Tubes}

The present invention relates to a vacuum gauge using carbon nanotubes (hereinafter referred to as CNTs), and more particularly to carbon nanotubes composed of electrode tips for electron emission for electric field emission by coating or depositing / growing CNTs. It relates to a vacuum gauge using.

In general, as a representative example of the field emission is applied to the measuring device is an ion gauge for vacuum measurement.

The ion gauge collects and amplifies ions generated by the electrons emitted from the electron emitters when colliding with the gas molecules, and measures the vacuum pressure based on them. It is a structure of a 3-pole vacuum tube composed of a vacuum container made of glass and a filament, a grid, and a collector built in the vacuum container, and a port is formed in the vacuum container.

As shown in FIG. 1, the ion gauge for vacuum measurement, which is a device to which electric field emission is applied, is provided with a filament 20 extending upward and downward as an electron emitter in the vacuum container 10, and the side of the filament 20. The grid 30 shape | molded by the coil structure is located in this. In the center of the coil structure, the ion collector 40 is disposed to be long, and each of the components is disposed in the vacuum container 10 in which the port 11 is formed at one side.

As shown in FIG. 2, the filament 20 is heated as a voltage is applied to emit hot electrons 20a. The hot electrons 20a are emitted as the filament 20 is heated. At this time, the grid 30 is positive, so that the electrons 20a are accelerated to the grid 30.

The electrons 20a accelerated to the grid 30 ionize the gas molecules 10a while colliding with the gas molecules 10a in the vacuum vessel 10. As a result, the number of cations 40a in the vacuum vessel 10 increases. The density of the cations 40a generated is generated in proportion to the gas molecular weight in the vacuum vessel 10.

At this time, the cations 40a of the ionized gas molecules 10a are collected by the collector 40. At this time, a current by ions is generated in proportion to the pressure in the vacuum vessel 10 and flows to the collector 40. This value is converted into pressure so that the vacuum pressure is finally measured.

The collector 40 is connected to the amplifier outside the vacuum vessel 10. The amplifier amplifies the current. In the meter, the current value is converted into a pressure value and displayed.

1 is a structure of the most widely used B-A gauge (Bayard-Alpert Gauge). By the way, the conventional gauge is a hot electron emission structure by the resistance heating of the filament 20 to implement the field emission. In the hot electron emission process, gaseous pollutants are released. The contaminants cause contamination that is deposited black on the inner surface of the vacuum container 10 made of glass.

The deposition of such contaminants acts as a problem of disturbing the clean environment inside the vacuum vessel 10 and also acts as a gas emission source inside the vacuum vessel 10 to increase the measurement error.

Therefore, the cleaning of the vacuum vessel 10 is necessary. Cleaning of the vacuum vessel (10) is made of a mixed solution of calcium dichromate and sulfuric acid to make a cleaning solution, put the vacuum vessel (10) and then cut, and then relatively complicated process such as distilled water washing, ethyl alcohol washing, acetone washing, ultrasonic washing, drying, etc. Is done through. In other words, the removal of the contaminant is an important variable to determine the success or failure of the pressure measurement. This cleaning process of the vacuum vessel 10 is required by the problem of the hot electron emission structure of the filament (20).

In addition, the conventional ion gauge basically has a hot electron emission structure using the filament 20 as described above. By the way, the filament 20 is a problem that is frequently cut during use has a cumbersome problem to repeat the replacement accordingly.

In spite of the simplicity of the basic structure, the filament 20, the coil 30, and the collector 40 have all the components, and the glass is used as the vacuum container 10, so the volume is relatively large and vacuum. There is a problem that the container 10 is easily broken and difficult to store. In addition, the mass production is not easy, there is a problem that the productivity is low.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and a first object of the present invention is to provide a vacuum gauge using carbon nanotubes that can achieve miniaturization and integration by applying CNT as an electron emission structure. .

A second object of the present invention is to provide a vacuum gauge using carbon nanotubes, which greatly improves the reliability of pressure measurement by eliminating pollutant discharge due to gas discharge.

Objects of the present invention as described above, the vacuum container is provided with a connection port so that the gas molecules;

A base formed on an inner wall surface of the vacuum container;

A carbon tube layer composed of a plurality of carbon nanotubes focused on the base and emitting electrons upon application of a negative voltage;

A grid in which a plurality of gates of a corresponding size are passed through the electrons spaced apart from each other on the base to pass the electrons; And

It is achieved by a vacuum gauge using carbon nanotubes, characterized in that it comprises a collector disposed at a predetermined interval on the grid and collects the cations of the gas molecules generated by the collision of electrons.

Here, the metal base layer preferably forms a plane.

Correspondingly, the grid is preferably a planar structure having a predetermined gap on the base.

And it is preferable that the base forms a curved surface.

Correspondingly, the grid is preferably a curved structure having a corresponding curvature such that the grid is disposed with a predetermined gap on the base.

Wherein the carbon nanotubes are preferably arranged regularly so that one end toward the grid.

Alternatively, the carbon nanotubes may be mixed and arranged irregularly.

Here, the base is preferably a metal layer applied by screen printing.

Correspondingly, the carbon tube layer is preferably formed by coating the carbon nanotubes on the base.

The base may include a silicon layer and a catalyst metal layer including iron, nickel, and cobalt embedded in each groove etched and etched in the silicon layer.

Correspondingly, the carbon tube layer is preferably formed by depositing / growing the carbon nanotubes on the catalyst metal layer by a thermochemical vapor deposition method.

At this time, it is preferable that a spacer made of an insulating mineral is interposed between the grid and the base so that the grid is spaced apart.

Alternatively, a spacer made of an insulating polymer resin may be interposed between the grid and the base so that the grid is spaced apart from each other.

Here, the spacer preferably has a height relatively smaller than a predetermined distance between the grid and the collector.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, a vacuum gauge using carbon nanotubes according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a configuration diagram of the vacuum gauge according to the first embodiment of the present invention, Figure 4 is a configuration diagram of the carbon tube layer shown in FIG.

3 and 4, the vacuum gauge 1000 according to the present invention is a kind of carbon allotrope, a CNT 310 having a long thin tube-shaped structure having a diameter of several nm, the electron emission electrode It is a gauge device constructed as a tip.

The vacuum gauge 1000 includes a base, a carbon tube layer 300, a grid 400, and a collector 500 disposed in the vacuum container 100 having the connection port 110. The carbon tube layer 300 is formed on the base, and the grid 400 and the collector 500 are disposed thereon.

At this time, the carbon tube layer 300 becomes a cathode electrode applied with a negative voltage, and the grid 400 becomes an anode electrode applied with a positive voltage. The collector 500 takes a negative voltage because it needs to collect the positive ions 500a. Therefore, it has a structure of three-pole vacuum tube.

The base is a metal layer 210 which is applied to the inner wall surface of the vacuum container 100 made of glass by heat treatment for bonding to the inner wall surface. The carbon tube layer 300 is formed on the metal layer 210. Therefore, an external power source is electrically connected through the metal layer 210 so that a voltage is applied to the carbon tube layer 300. When the metal layer 210 is formed by screen printing, silver having a good conductivity is used for smooth voltage application.

If the inner wall surface of the vacuum vessel 100 is a curved surface, the metal layer 210 also has a curved structure accordingly, and the carbon tube layer 300 formed on the metal layer 210 also has a curved structure. Alternatively, when the inner wall of the vacuum vessel 100 is flat, the metal layer 210 and the carbon tube layer 300 have a flat structure.

The carbon tube layer 300 is formed of a CNT 310 that is concentrated on the metal layer 210 by applying a plurality of CNTs 310 combined with an adhesive on the metal layer 210 and heat evaporating the adhesive by heat treatment. . At this time, the focused CNTs 310 are uniformly arranged or arranged according to a coating method.

In FIG. 4, the CNTs 310 forming the carbon tube layer 300 having a predetermined arrangement among them are illustrated as one end of each CNT 310 toward the grid 400 disposed thereon. When a voltage is applied to the metal layer 210, each CNT 310 contacted meets a field emission condition by forming an advanced structure having both ends of several nanometers. Therefore, the individual CNTs 310 function as electrode tips for electron emission. According to this shape, even if a small voltage is applied, the electrons 300a may be emitted from the CNT 310.

The grid 400 forms a plurality of minute pinholes in the copper plate. The pinhole is a gate 410 through which the electron 300a passes. The grid 400 has a positive polarity so that the electrons 300a are electric fields up to the gate 410. Substantially, the two electrodes in the vacuum vessel 100 function as the carbon tube layer 300 and the grid 400 including the metal layer 210, the grid 400 is the emission electrons of the carbon tube layer 300 ( It functions as an inductive electrode for accelerating 300a). The electrons 300a emitted from the CNTs 310 are induced electric fields and accelerated toward the grid 400. The gate 410 passes through the gate 410.

The grid 400 is spaced apart from each other by a predetermined gap on the carbon tube layer 300. To this end, spacers 600 are disposed at both ends of the metal layer 210. The spacer 600 may be an insulating material, but in the present invention, a mica or polymer-based insulating resin material is used. The height of the spacer 600 is within about 1 mm. Therefore, the grid 400 maintains a gap corresponding to the height, and the electric field emission is realized between the grid 400 and the carbon tube layer 300.

As mentioned above, the metal layer 210 and the carbon tube layer 300 have a curved or planar structure according to the inner wall shape of the vacuum container 100. When the metal layer 210 has a curved structure corresponding to the metal layer 210, the grid 400 has a curved structure having a corresponding curvature to maintain a predetermined gap. Even when the metal layer 210 has a planar structure, the metal layer 210 has a planar structure disposed with a predetermined gap.

The collector 500 is disposed on the grid 400. The collector 500 is a conductive metal processed into a bar shape. A negative voltage is applied to the collector 500. Between the collector 500 and the grid 400, gas molecules 100a introduced into the vacuum container 100 from the outside through the connection port 110 and electrons 300a passing through the gate 410 are mixed. . The electron 300a collides with the gas molecule 100a to generate a cation 500a.

The gap between the collector 500 and the grid 400 is greater than that of the grid 400 in order to introduce more gas molecules 100a to create a more smooth collision environment between the electrons 300a and the gas molecules 100a. It is preferable to be relatively larger than the gap with the metal layer 210. In the present invention, the collector 500 is disposed so that the distance between the grid 400 and the collector 500 is within a few cm.

5 is a state diagram used in the vacuum gauge according to the first embodiment of the present invention.

As shown in FIG. 5, a negative voltage is applied to the metal layer 210 and the collector 500, and a positive voltage is applied to the grid 400.

Then, a voltage is applied to the carbon tube layer 300 electrically connected to the metal layer 210, and electrons 300a are emitted from the end of the CNT 310 forming the carbon tube layer 300. The emitted electron 300a is accelerated by the electric field to the grid 400 and passes through the gate 410.

The gas molecules 100a are introduced into the vacuum vessel 100 through the connection port 110 of the vacuum vessel 100. The gas molecules 100a are distributed between the collector 500 and the grid 400 having a relatively large distance.

The electrons 300a passing through the gate 410 collide with the gas molecules 100a and ionize the gas molecules 100a. In this process, the cation 500a is generated. The cation 500a moves to the collector 500 and is collected. That is, ion currents are generated as cations 500a gather around the collector 500.

The ion current is taken out to outside through the collector 500 and amplified to a size measurable by the amplifier 1100. Since the ion current and the pressure in the vacuum vessel 100 are proportional to each other, the meter 1200 displays this in pressure units.

6 is a configuration diagram of a carbon tube layer according to a second embodiment of the present invention.

As shown in FIG. 6, the carbon tube layer 300 may be formed by depositing / growing the CNT 310. In the present invention, for this purpose, Thermal Chemical Vapor Deposition is used. Silicon and a catalyst metal for promoting growth are introduced for the deposition method.

In order to form the base, the silicon layer 220 is formed on the inner wall surface of the vacuum vessel (100). A plurality of fine grooves are formed in the silicon layer 220 by etching etching. In each of the grooves, a catalyst metal layer 220a made of iron, nickel, and cobalt is formed as part of a thermochemical vapor deposition method. That is, the base has a structure in which the catalyst metal layer 220a is formed for each groove on the silicon layer 220.

The CNTs 310 are placed on the catalytic metal layer 220a and deposited using the thermochemical vapor deposition method. The deposited CNTs 310 are grown to form a carbon tube layer 300.

The grid 400 is disposed on the carbon tube layer 300 at a predetermined gap. The collector 500 is disposed on the arranged grid 400. The carbon tube layer 300 and the collector 500 formed as described above are provided with a structure of a three-pole vacuum tube in which a negative voltage is applied to the carbon tube layer and a positive voltage is applied to the grid 400.

In the carbon tube layer 300, electrons 300a are emitted. The emitted electrons 300a are electric fields into the grid 400, accelerated while passing through the gate 410, and collide with the gas molecules 100a between the grid 400 and the collector 500. In this process, cations 500a are generated and collected in the collector 500. An ion current flows through the collected cations 500a and amplifies and detects the vacuum pressure based on a proportional relationship between the pressure and the ion current.

In the vacuum gauge 1000 using the carbon nanotubes according to the present invention as described above, the grid 400 is a plate structure, hollow rod structure, solid of the plate structure in addition to the curved surface, flat plate shape, the surface is repeated It can be selected and used in a bar structure, etc. In each of the above-described structures, a plurality of pinholes are formed in a size that allows electrons 300a to pass as the gate 410.

In addition, the CNT 310 has a tube-shaped basic unit structure, such as a single wall structure, a multi-wall structure, a rope structure, and the existing CNT 310 and the processed structure CNT ( 310 may be used.

In addition to the silver exemplified as the material of the metal layer 210 coated by the screen printing method, gold, copper, aluminum, or the like may be used as a material generally used as a conductive metal.

In addition, the base, the carbon tube layer 300, the grid 400, and the collector 500, which are embodied and set in the present invention, are described as an example, and in addition to the base, carbon over the entire inner wall of the cylindrical vacuum container 100. The tube layer 300 may be formed, a cylindrical grid 400 may be disposed corresponding thereto, and a collector 500 may be disposed along the axial direction in the center of the grid 400.

In addition, the base and carbon tube layers 300 are formed on four inner wall surfaces of the vacuum vessel 100 having a rectangular cross section, and correspondingly, the grid 400 of the rectangular cross section or four grids 400 corresponding to each base individually. It will be possible to configure the structure of arranging and arranging the collector 500 in the center.

According to the vacuum gauge using the carbon nanotubes according to the present invention as described above, avoiding the conventional hot electron emission method accompanied with the generation of a new gas that can cause a pressure change in the hot electron emission structure to emit electrons as field emission In addition, there is a feature that can accurately and reliably measure the vacuum pressure to be originally measured.

In addition, since the nanometer-sized CNT is used as the electrode tip for emitting electrons, the size of the gauge can be further miniaturized, and thus, the vacuum pressure of various objects can be measured by putting it in a loading place.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

1 is a configuration diagram of an ion gauge for conventional vacuum measurement,

Figure 2 is a state of use of the conventional ion gauge for vacuum measurement,

3 is a block diagram of a vacuum gauge according to a first embodiment of the present invention,

4 is a configuration diagram of the carbon tube layer shown in FIG.

5 is a state diagram used in the vacuum gauge according to the first embodiment of the present invention,

6 is a configuration diagram of a carbon tube layer according to a second embodiment of the present invention.

<Description of the code | symbol about the principal part of drawing>

10: vacuum container 10a: gas molecule

11: port 20: filament

20a: electron 30: grid

40: collector 40a: cation

100: vacuum container 100a: gas molecule

110: connection port 210: metal layer

220: silicon layer 220a: catalytic metal layer

300: carbon tube layer 300a: electron

310: carbon nanotube (CNT) 400: grid

410: gate 500: collector

500a: cation 600: spacer

1000: vacuum gauge 1100: amplifier

1200 meters

Claims (14)

A vacuum container 100 having a connection port 110 so that the gas molecules 100a flow in; A base formed on an inner wall surface of the vacuum container 100; A carbon tube layer 300 composed of a plurality of carbon nanotubes 310 focused on the base and emitting electrons 300a according to the application of a negative voltage; A grid 400 through which a plurality of gates 410 having a corresponding size pass through the electrons 300a spaced apart from each other on the base; And a collector 500 disposed at a predetermined interval on the grid 400 and collecting the cations 500a of the gas molecules 100a generated by the collision of electrons 300a. In the gauge, The base includes a silicon layer 220 and a catalyst metal layer 220a including iron, nickel, and cobalt embedded in each groove etched in the silicon layer 220, The carbon tube layer 300 is a vacuum gauge using carbon nanotubes, characterized in that the carbon nanotubes 310 are deposited / grown on the catalytic metal layer (220a) by a thermochemical vapor deposition method. The vacuum gauge using carbon nanotubes of claim 1, wherein the base forms a plane. The vacuum gauge using carbon nanotubes of claim 2, wherein the grid 400 has a planar structure having a predetermined gap on the base. The vacuum gauge using carbon nanotubes of claim 1, wherein the base forms a curved surface. The vacuum gauge using carbon nanotubes according to claim 4, wherein the grid 400 has a curved structure having a corresponding curvature so as to be arranged with a predetermined gap on the base. The vacuum gauge using carbon nanotubes of claim 1, wherein the carbon nanotubes 310 are regularly arranged so that one end thereof faces the grid 400. The vacuum gauge using carbon nanotubes according to claim 1, wherein the carbon nanotubes 310 are randomly arranged and mixed. The vacuum gauge using carbon nanotubes according to claim 1, wherein the base is a metal layer (210) coated by screen printing. The vacuum gauge using carbon nanotubes of claim 8, wherein the carbon tube layer (300) is formed by coating the carbon nanotubes (310) on the base. delete delete The vacuum gauge using carbon nanotubes of claim 1, wherein a spacer (600) made of an insulating mineral is interposed between the grid (400) and the base so that the grid (400) is spaced apart from each other. The vacuum gauge using carbon nanotubes of claim 1, wherein spacers 600 made of an insulating polymer resin are interposed between the grid 400 and the base so that the grid 400 is spaced apart from each other. The vacuum gauge using carbon nanotubes of claim 12 or 13, wherein the spacer 600 has a height that is relatively smaller than a predetermined interval between the grid 400 and the collector 500.