JP3889380B2 - Hot cathode and discharge device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hot cathode and a discharge device using the same, and more particularly to a hot cathode used for illumination and the like and a discharge device using the same.
[0002]
[Prior art]
In a conventional general hot cathode discharge lamp, electrons emitted from the cathode by discharge collide with mercury atoms sealed in the discharge tube, and the mercury atoms receive energy by the collision and emit ultraviolet rays. This ultraviolet light excites the phosphor to generate visible light. The emission color varies depending on the type of phosphor, and various types of light such as white, daylight, and blue are emitted from the lamp.
[0003]
The filament during discharge reaches 1000 degrees or more, and the emitter applied to the coil evaporates, or is sputtered by ion or electron collision and consumed. Due to such evaporation and sputtering, the electron emitting material diffuses into the glass tube. The diffused electron emitting material adheres to the inner surface of the glass tube and reacts with mercury to form amalgam and blacken. This phenomenon not only impairs the appearance, but also causes a decrease in the luminous flux of the lamp.
[0004]
There are many means for preventing the exhaustion of electron-emitting materials. For example, there is a structure in which the electron emitting material is diamond which is a material that is difficult to be sputtered (see Patent Documents 1 and 2). In the inventions described in these documents, diamond particles are adhered to the electrode material by coating. In order to apply and adhere, for example, diamond particles are mixed in an organic solvent and the electrode material is immersed in this solution, and ultrasonic cleaning is performed.
[0005]
However, according to the inventor's research, when diamond is used as the electron-emitting substance, the etching or consumption of diamond by sputtering is small, but the adhesion between metals as electrode materials such as tungsten and diamond is poor. Further, it was newly found out that diamond peeling frequently occurred from the electrodes due to the difference in stress, and the production yield and durability of the discharge device such as a hot cathode discharge lamp were remarkably inferior.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-69868
[Patent Document 2]
JP 2000-106130 A
[0007]
[Problems to be solved by the invention]
As described above, conventionally, a discharge device such as a hot cathode discharge lamp using diamond as an electron-emitting substance has poor adhesion between metals as an electrode material, for example, tungsten and diamond, and the diamond peels off from the electrode. Frequently occurred, and the production yield and durability of the discharge device were remarkably inferior.
[0008]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a hot cathode capable of improving the production yield and durability of a hot cathode discharge device and a discharge device using the hot cathode.
[0009]
[Means for Solving the Problems]
(Constitution)
In order to solve the above-described problem, the first hot cathode of the present invention includes a coiled electrode and a cylindrical diamond having an inner diameter substantially the same as the coil outer diameter of the coiled electrode. only A diamond member made of The diamond member is in contact with only the outer surface of the coiled electrode and is slidable with the outer surface. It is characterized by that.
[0012]
The third hot cathode of the present invention is Columnar Electrodes and this Columnar Diamond provided on the outer surface of the electrode so as to be slidable with the outer surface only The diamond member which consists of, It is characterized by the above-mentioned.
[0014]
In addition, the first to the first of the present invention 2 In the hot cathode, the diamond member is preferably made of diamond containing donor impurities.
[0015]
The first discharge device of the present invention is a discharge device including an envelope in which a discharge gas is sealed, and a hot cathode disposed in the envelope, wherein the hot cathode is: A cylindrical diamond having a coiled electrode and an inner diameter substantially the same as the coil outer diameter of the coiled electrode only A diamond member made of The diamond member is in contact with only the outer surface of the coiled electrode and is slidable with the outer surface. It is characterized by that.
[0018]
The third discharge device of the present invention is a discharge device including an envelope in which a discharge gas is sealed, and a hot cathode disposed in the envelope, wherein the hot cathode is: Columnar Electrodes and this Columnar Diamond provided on the outer surface of the electrode so as to be slidable with the outer surface only The diamond member which consists of, It is characterized by the above-mentioned.
[0020]
In the first to third discharge devices of the present invention, it is desirable to have the following configuration.
[0021]
(1) The diamond member is made of diamond containing donor impurities.
[0022]
(2) The discharge gas includes a gas containing an element having a main emission peak of 200 nm or less.
[0023]
(3) The discharge gas contains a rare gas and mercury.
[0024]
(4) The discharge gas contains Xe.
[0025]
(5) The discharge gas contains hydrogen gas.
[0026]
In the present invention, for a diamond member made of cylindrical diamond having an inner diameter that is substantially the same as the coil outer diameter of the coiled electrode, “substantially the same size” refers to the coil outer diameter. This means that a cylindrical diamond member having an inner diameter that is larger by a size within 0.2 mm is included.
[0027]
In the present invention, a diamond member made of diamond provided on the outer surface of the electrode so as to be slidable with the outer surface means “slidable” means that the electrode and the diamond member are chemically and physically fixed. It means that the electrode and the diamond member can be slid separately.
[0028]
(Function)
According to the present invention, a diamond member made of diamond is slidably provided on an electrode having a coil shape or the like. In the case of a coiled electrode, a diamond member made of cylindrical diamond having an inner diameter substantially the same as the coil outer diameter of the coiled electrode is provided.
[0029]
According to the present invention, the electrode member and the diamond member are not firmly fixed, and therefore, film peeling resulting from a difference in stress between the electrode member and the diamond member does not occur essentially. Can be greatly improved. In addition, since the diamond member has a high thermal conductivity, sufficient heat is transmitted from the electrode, and sufficient thermal conductivity characteristics can be obtained even in comparison with a conventional fixed structure.
[0030]
Furthermore, when diamond is used as an electron emitting material in a discharge device using a hot cathode, since diamond has high sputtering resistance, problems such as exhaustion of the electron emitting material due to sputtering by plasma during discharge can be improved. Is possible. In the case where the diamond member is a continuous film, the above-described effect becomes remarkable by the continuous film protecting the entire surface of the electrode.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0032]
(First embodiment)
FIG. 1 is a schematic view showing the structure of a hot cathode discharge lamp according to the discharge device of the present invention. FIG. 1A is an overall view of a hot cathode discharge lamp, and FIG. 1B is an enlarged cross-sectional view showing the configuration of electrodes.
[0033]
As shown in FIG. 1A, the hot cathode discharge lamp according to this embodiment includes a glass tube (discharge tube) 10 as an envelope having a phosphor 12 applied on the inner surface, and both ends of the glass tube 10. A pair of attached electrodes 11a and 11b, a pair of lead wires 11c and 11d, a pair of metal fittings 14a and 14b, and diamond members 15a and 15b made of cylindrical diamond provided on the pair of electrodes 11a and 11b. And is constituted by. The lead-in wires 11c and 11d are for holding the electrodes 11a and 11b and energizing them, and are held by a pair of metal fittings 14a and 14b, respectively. Further, in order to facilitate discharge, the glass tube 10 is sealed with argon or a mixed rare gas and a slight amount of mercury as a sealing gas 13 at a pressure of 2 to 4 hPa.
[0034]
As shown in the enlarged view of FIG. 1B, the pair of electrodes 11a and 11b are composed of single, double, or more coiled filaments (for example, tungsten or the like). The cylindrical diamond members 15a and 15b are provided on the outer surfaces of the coiled electrodes 11a and 11b so as to be slidable with the outer surfaces. The diamond members 15a and 15b have an inner diameter that is substantially the same as the coil outer diameter of the coiled electrodes 11a and 11b, and are not fixed to the coiled electrodes 11a and 11b.
[0035]
At the time of discharge, if current is passed through the coiled electrodes 11a and 11b and preheating is performed, electrons are emitted from the diamond members 15a and 15b (emitters) that have become hot. The emitted electrons move to the counter electrode (anode) and discharge starts. Here, in general, an AC voltage is applied to the coiled electrodes 11a and 11b to cause discharge, and when one of the coiled electrodes 11a and 11b acts as an emitter, the other is a counter electrode. Acts as (anode). Due to this discharge, the emitted electrons collide with mercury atoms sealed in the glass tube 10. Alternatively, the emitted electrons collide with excited argon or mixed rare gas atoms to excite them, and the excited atoms collide with mercury atoms. Mercury atoms receive energy by the collision and emit ultraviolet rays. The phosphor 12 is excited by the ultraviolet rays to generate visible light. The emission color varies depending on the type of phosphor, and various types of light such as white, daylight, and blue are emitted from the lamp.
[0036]
In the hot cathode of the present embodiment, cylindrical diamond members 15a and 15b having an inner diameter substantially the same as the outer diameter of the coiled electrodes 11a and 11b are provided. The diamond members 15a and 15b are not fixed to the coiled electrodes 11a and 11b, and are slidable with respect to the outer surfaces of the coiled electrodes 11a and 11b. For this reason, the hot cathode of the present embodiment is free from the problem of film peeling. Further, since the diamond members 15a and 15b have high sputtering resistance, the diamond members 15a and 15b as continuous films are used as electrode materials for the coiled electrodes 11a and 11b even if the hot cathode is exposed to the sputtering of the discharge gas in the discharge device. Since it plays the role of protecting the entire surface, it is possible to remarkably improve the durability of the hot cathode.
[0037]
Next, the manufacturing method of the hot cathode in the hot cathode discharge lamp of this embodiment is demonstrated. FIG. 2 is a sectional view showing the manufacturing method.
[0038]
First, as shown in FIG. 2A, coiled electrodes 11a and 11b made of tungsten or the like are prepared. The pitch of the coiled electrodes 11a and 11b is zero. The coiled electrodes 11a and 11b are subjected to diamond seeding treatment, the treated coiled electrodes 11a and 11b are placed in a microwave plasma CVD apparatus, and diamond members 25a and 25b are placed on the surfaces of the coiled electrodes 11a and 11b. Form a film.
[0039]
Here, the diamond seeding process for the coiled electrodes 11a and 11b will be described. First, diamond particles were mixed with an organic solvent such as alcohol, and this solvent was applied to the surfaces of the coiled electrodes 11a and 11b. A carbon-based thin film such as graphite may be formed on the surfaces of the coiled electrodes 11a and 11b, and the solvent may be applied to the surface of the carbon-based thin film. The diamond particles mixed with the organic solvent had a particle size of 0.1 to 1 micron. As the coating, a method of ultrasonic cleaning by immersing the coiled electrodes 11a and 11b in an organic solvent mixed with diamond particles was adopted.
[0040]
Further, when diamond particles are applied, the diamond members 25a and 25b (corresponding to the diamond members 15a and 15b) are formed into a cylindrical shape by masking portions where the diamond members 25a and 25b are not formed. It was considered not to be applied to the excess part. Here, the processing time by ultrasonic cleaning was 30 minutes. By ultrasonic cleaning, the diamond particles uniformly adhered to the surfaces of the coiled electrodes 11a and 11b. Thereafter, if necessary, for example, a heat treatment was performed at a temperature of 200 ° C. in a nitrogen atmosphere for 60 minutes to remove the organic solvent and impurities.
[0041]
Next, the process of forming the diamond members 25a and 25b on the surfaces of the coiled electrodes 11a and 11b will be described. FIG. 6 is a cross-sectional view showing a configuration of a microwave plasma CVD apparatus used in this film forming process.
[0042]
As shown in FIG. 6, the microwave passes through the microwave waveguide 62b from the microwave head 62a, and is further introduced into the reaction chamber 63 through the quartz window 64 for microwave introduction. On the other hand, the reaction gas is introduced into the reaction chamber 63 from the reaction gas inlet 65. A sample 60 (corresponding to the electrode materials 11a and 11b) is placed on the heater stage 61. The support stage of the heater stage 61 can be adjusted in the vertical position and has a mechanism that can be adjusted to an optimum position. The pressure in the reaction chamber 63 is controlled by a pressure adjustment valve (not shown). The exhaust system 66 includes a rotary pump 66a, a turbo molecular pump 66b, and a rotary pump 66c. Normal exhaust of reaction gas or the like is performed by a rotary pump 66a. In addition, evacuation is performed by a turbo molecular pump 66b and a rotary pump 66c. Reference numeral 67 denotes a motor power supply, which drives the motor and rotates the heater stage 61.
[0043]
The film formation conditions for the diamond thin film (diamond members 25a and 25b) in this case are as follows. That is, a diamond thin film (diamond member 25a, 5 μm thick) with a microwave power of 4 kW, a reaction gas pressure of 13.3 kPa, a hydrogen gas flow rate of 400 sccm, a methane gas flow rate of 8 sccm, a substrate temperature of 850 ° C. and a film formation time of 120 minutes. 25b) was formed.
[0044]
In this embodiment, only hydrogen gas and methane gas are used for forming the diamond thin film. However, deuterium plasma treatment is performed at a high temperature of about 550 ° C. on an n-type material such as phosphorus, nitrogen, sulfur, or boron-doped diamond. It is also possible to use a material exhibiting n-type, or a material exhibiting n-type annealed at an appropriate temperature (for example, 520 ° C.) and time (for example, 30 minutes). In addition, a p-type material such as boron may be doped as an impurity. The n-type dopant will be described later in detail. The method for forming the diamond thin film is not limited to the microwave plasma CVD method, and can be formed by, for example, a CVD method using ECR, a CVD method using high frequency (RF), or the like.
[0045]
Next, the diamond members 25a and 25b formed on the coiled electrodes 11a and 11b are separated from the coiled electrodes 11a and 11b. As a method of pulling apart, there is a method of pulling the both ends of the coiled electrodes 11a, 11b lightly, etc., thereby making it possible to easily separate the diamond members 25a, 25b from the coiled electrodes 11a, 11b by making the pitch larger than zero. Is possible. As a result, the diamond members 25a and 25b are only in contact with the surfaces of the coiled electrodes 11a and 11b without being fixed, and the film is peeled off due to differences in thermal expansion coefficient and stress from the materials of the coiled electrodes 11a and 11b. The problem is essentially nonexistent.
[0046]
Thereafter, lead wires 11c and 11d for holding the coiled electrodes 11a and 11b and energizing are connected to the coiled electrodes 11a and 11b, respectively, and the metal fittings 14a and 14b are attached to the lead wires 11c and 11d, respectively. Furthermore, these metal fittings 14a and 14b are attached to the glass tube 10 having the inner surface coated with the phosphor 12, and sealed with a sealing gas to complete a discharge device (discharge lamp).
[0047]
(Second Embodiment)
The hot cathode of the present embodiment is one in which a cylindrical diamond member is not formed on a coiled electrode but formed separately, and then the coiled electrode is inserted into the diamond member.
[0048]
The manufacturing method of the hot cathode of this embodiment will be described. FIG. 3 is a process sectional view showing the manufacturing method.
[0049]
First, as shown in FIG. 3A, a metal rod having an appropriate diameter, for example, a tongues rod 31 having a diameter of 3 mm and a length of 10 mm is prepared. Next, as described in the first embodiment, as a diamond seeding process, the tongue rod 31 is immersed in an organic solvent containing diamond particles, and ultrasonic cleaning is performed for 30 minutes. At this time, as shown in FIG. 3 (b), masking 32a and 32b are applied to both ends of the tungsten rod 31 so that diamond particles do not adhere to both ends.
[0050]
For the formation of the diamond member 33, the microwave plasma CVD method described in the first embodiment was used. As shown in FIG. 3 (c), after the diamond member 33 is formed on the part where the diamond particles are adhered, the tungsten rod 31 and the masking 32a and 32b are completely removed by etching as shown in FIG. 3 (d). To do. For the etching, aqua regia (a mixture of hydrochloric acid and nitric acid) was used. By this step, a cylindrical diamond member 33 having an inner diameter of 3 mm is obtained.
[0051]
Next, a hot cathode structure shown in FIG. 3E is manufactured by inserting a coiled electrode 34 having an outer diameter that is the same as or slightly smaller than the inner diameter of the diamond member 33 into the cylindrical diamond member 33. The As the coiled electrode 34 having an outer diameter slightly smaller than the inner diameter of the diamond member 33, a coiled electrode 34 having an outer diameter smaller by 0.2 mm or less than the inner diameter of the cylindrical diamond member 33 is used. Is possible. Thereafter, the discharge device (discharge lamp) is completed in the same manner as in the first embodiment.
[0052]
Also in the hot cathode of the present embodiment, the diamond member 33 is not fixed to the coiled electrode 34 and is slidable with respect to the outer surface of the coiled electrode 34. For this reason, the hot cathode of this embodiment is also free from the problem of film peeling.
[0053]
Moreover, when the method of this embodiment is used, the shape of the electrode is not limited to a coil shape, and the present invention can be applied to electrodes having other shapes. For example, the present invention can be applied to a rod-shaped or flat electrode. This form will be described later in the third embodiment.
[0054]
(Third embodiment)
In the present embodiment, a hot cathode in the case where the method of the second embodiment is applied to a rod-shaped electrode will be described.
[0055]
The manufacturing method of the hot cathode of this embodiment will be described. FIG. 5 is a process sectional view showing the manufacturing method.
[0056]
Since FIG. 5A to FIG. 5D are the same as those in the second embodiment, description thereof will be omitted. As shown in FIG. 5E, the hot cathode structure shown in FIG. 5 is obtained by inserting a rod-shaped electrode 44 having an outer diameter that is the same as or slightly smaller than the inner diameter of the diamond member 33 into the cylindrical diamond member 33. Manufactured. As the rod-shaped electrode 44 having an outer diameter slightly smaller than the inner diameter of the diamond member 33, a rod-shaped electrode 44 having an outer diameter smaller than the inner diameter of the cylindrical diamond member 33 by 0.2 mm or less can be used. is there.
[0057]
(Fourth embodiment)
In the present embodiment, an example in which the above-described diamond member is doped with an impurity exhibiting n-type conductivity will be described. FIG. 4 is a diagram for explaining the principle of this embodiment, and is a band diagram of diamond doped with n-type impurities. It is known that diamond exists at a position where the vacuum level indicated by Evac is lower than the bottom of the conduction band of diamond indicated by Ec and has a negative electron affinity called NEA (Negative Electron Affinity). Electron affinity is the energy required to move the electrons at the bottom of the conduction band into the vacuum, and having a negative value means that the electrons are very likely to be emitted.
[0058]
However, n-type doped diamond has extremely high resistance at room temperature, and when diamond is used as a cold cathode, attempts to realize a highly efficient cathode using its NEA characteristics have not been successful. This is because the energy difference Ed between the level of the donor that gives electrons and the bottom of the conduction band is more than 10 times that of a normal semiconductor such as Si, and electrons hardly exist in the conduction band at room temperature.
[0059]
However, it has been found that sufficiently excellent electron emission characteristics can be obtained when n-type doped diamond is applied to a discharge device such as a fluorescent lamp and heated. In the present embodiment, a hot cathode using such excellent electron emission characteristics and a discharge device having excellent light emission characteristics will be described.
[0060]
As described above, when heating n-type doped diamond, electrons rise to the conduction band as the temperature rises, so that electron emission utilizing NEA characteristics becomes possible. That is, in the NEA diamond, there is no barrier that prevents electrons in the conduction band from being released into the vacuum, so that the energy required to emit the electrons is about Ed. On the other hand, in a normal electron emitting material that does not have NEA characteristics, the vacuum level Evac is above the bottom Ec of the conduction band, and the energy required to emit electrons in the vacuum is a value about the work function. Become. The value of Ed is about 0.6 eV when diamond is doped with phosphorus, while the work function is about 1.1 eV in BaO often used for thermionic emission emitters. is there. These values have an exponential effect on thermionic emission, so that n-type doped diamond can emit thermoelectrons at a low temperature. Accordingly, in a discharge device such as a fluorescent lamp using such a hot cathode, uniform thermionic emission can be realized at a low temperature, thereby providing a hot cathode discharge device having excellent light emission characteristics and a long life. Can do.
[0061]
Further, the work function is extremely sensitive to the influence of the surface state, and is strongly influenced by the manufacturing process, atmosphere, and the like. For this reason, it is difficult to expect uniformity within the electron emission surface. Since the work function value has an exponential effect on thermionic emission, the inhomogeneity in the plane of thermionic emission tends to be large.
[0062]
On the other hand, in the case of NEA diamond, as long as the electron affinity is negative, even if the value fluctuates slightly, it does not affect thermionic emission, and thermionic emission is determined by the donor level and conduction. This is the energy difference Ed from the bottom of the band. This value is not a surface property, but a bulk property determined by the dopant. For this reason, n-type diamond can be expected to emit uniform thermionic electrons within the surface. Furthermore, diamond is the substance with the highest thermal conductivity, and even when heated by Joule heat, inflow of ions / electrons, or heating by impact, the heat is quickly transferred to the surroundings and the temperature becomes uniform. A sufficient effect can be obtained only by using n-type diamond. However, when the shape is a uniform continuous film, the effect becomes enormous.
[0063]
Next, the hot cathode and the discharge device according to this embodiment will be described. First, a filament is prepared by winding a tungsten wire having a wire diameter of 30 μm in a coil shape. This filament treatment was performed in the same manner as in the first embodiment. A diamond layer having a thickness of about 5 microns is formed on the filament by, for example, a microwave plasma CVD method. The growth conditions for the polycrystalline diamond layer were a microwave power of 4 kW, a hydrogen flow rate of 200 sccm, a methane gas flow rate of 4 sccm, and a methane concentration of the source gas of 2%. The pressure of the source gas was 13.3 kPa, the filament was heated to 850 ° C., and the film formation time was 120 minutes. Phosphorus was used as the n-type dopant, and phosphine gas was simultaneously supplied during diamond growth. The ratio of phosphine gas to methane gas was 1000 ppm.
[0064]
Next, the hot cathode structure is manufactured by separating the polycrystalline diamond layer formed on the filament in the same manner as in the first embodiment from the filament. Thereafter, the discharge device (discharge lamp) is completed in the same manner as in the first embodiment.
[0065]
Also in the hot cathode of this embodiment, the diamond layer is not fixed to the filament and is provided to be slidable with respect to the outer surface of the filament. For this reason, the hot cathode of this embodiment is also free from the problem of film peeling. Furthermore, by using n-type diamond as described above, uniform thermionic emission can be expected in the discharge surface, and it is possible to improve the light emission efficiency and the light emission stability.
[0066]
(Fifth embodiment)
In the present embodiment, the discharge hydrogen gas sealed in the hot cathode discharge lamp will be described.
[0067]
As in the first embodiment, a diamond produced by chemical vapor deposition (CVD) using a so-called hydrogen-based gas as a carrier gas generally has a surface terminated with hydrogen. This hydrogen termination layer greatly contributes to the characteristics of diamond and plays an important role in showing the above-mentioned NEA characteristics. For this reason, thermionic emission from a low temperature is attained from diamond. However, when the temperature rises to some extent, the hydrogen that terminates the surface of the diamond begins to desorb. The present embodiment is characterized by suppressing the detachment of hydrogen.
[0068]
Next, the configuration of the hot cathode discharge lamp of this embodiment will be described. The hot cathode formed with the diamond members 15a and 15b described in the first embodiment was used. A hot cathode discharge lamp was manufactured by sealing argon gas at 4 hPa as the sealing gas and hydrogen gas at a partial pressure ratio of 1 Pa. For comparison, a hot cathode discharge lamp without hydrogen gas was also produced. As a result of comparing the two, it was confirmed that the discharge lamp sealed with hydrogen had an improvement in luminous efficiency of about 3 times compared to the discharge lamp not sealed with hydrogen. The effect of improving luminous efficiency was remarkable when the partial pressure ratio of hydrogen gas to argon gas was 0.1% or more and 3% or less.
[0069]
As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. For example, the electrode material is not limited to tungsten, and other materials such as molybdenum can be used. Further, the shape of the electrode is not limited to a coil, a rod shape, or a wire shape, and for example, a plate shape, a film shape, or other shapes can be employed.
[0070]
In the present invention, a discharge gas containing an element having a main emission peak of 200 nm or less can be used. For example, a discharge gas containing a rare gas and mercury can be used. The rare gas is not limited to the above embodiment, and, for example, Xe gas can be used, and the luminous efficiency can be remarkably improved.
[0071]
In addition, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0072]
【The invention's effect】
According to the present invention, it is possible to greatly improve the durability of a discharge device having a diamond member as an electrode.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the structure of a hot cathode discharge lamp according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view for explaining the shape and manufacturing method of a hot cathode according to the first embodiment of the present invention.
FIG. 3 is a process cross-sectional view illustrating a method for manufacturing a hot cathode according to a second embodiment of the present invention.
FIG. 4 is a band diagram of diamond when an n-type conductivity impurity is doped in a diamond thin film.
FIG. 5 is a process cross-sectional view illustrating a method for manufacturing a hot cathode according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view showing a film forming apparatus used to form a diamond thin film.
[Explanation of symbols]
10 ... Glass tube
11a, 11b ... A pair of coiled electrodes
11c, 11d ... lead-in line
12 ... phosphor
13 ... Sealing gas
14a, 14b ... A pair of metal fittings
15a, 15b ... Diamond member
31 ... Tungsten rod
32a, 32b ... Masking part
33 ... Diamond member
34 ... Coiled electrode
44 ... Rod electrode
60 ... Sample
61 ... Heater stage
62a ... Microwave head
62b ... Microwave waveguide
63 ... Reaction chamber
64 ... Quartz window
65. Reaction gas inlet
66. Exhaust system
66a ... Rotary pump
66b ... turbo molecular pump
66c ... Rotary pump
67 ... Heater power supply

Claims (8)

A coil-shaped electrode, and a diamond member made of only cylindrical diamond having an inner diameter substantially the same as the coil outer diameter of the coil-shaped electrode, and the diamond member is formed only on the outer surface of the coil-shaped electrode. And a slidable contact with the outer surface of the hot cathode. A hot cathode comprising: a columnar electrode; and a diamond member made of only diamond provided on an outer surface of the columnar electrode so as to be slidable with the outer surface. The diamond member, hot cathode as claimed in any one of claims 1 to 2, characterized in that of diamond containing a donor impurity. A discharge device comprising an envelope filled with a discharge gas and a hot cathode disposed in the envelope, the hot cathode comprising a coiled electrode and an outer coil of the coiled electrode A diamond member composed of only a cylindrical diamond having an inner diameter substantially the same as the diameter, and the diamond member is in contact with only the outer surface of the coiled electrode and is slidable with the outer surface. discharge device, characterized in that are provided. A discharge device comprising an envelope filled with a discharge gas, and a hot cathode disposed in the envelope, wherein the hot cathode has a columnar electrode and an outer surface of the columnar electrode on the outer surface. And a diamond member made only of diamond provided so as to be slidable. The discharge gas, the discharge apparatus according to any one of claims 4 to 5, characterized in that it comprises a gas containing an element having the following major emission peak 200 nm. The discharge device according to any one of claims 4 to 6 , wherein the discharge gas contains a rare gas and mercury. Discharge device according to any one of claims 4 to 7 wherein the discharge gas is characterized in that it comprises a hydrogen gas.

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