JP2007207517A - Discharge plasma device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge plasma device capable of lowering discharge starting voltage between an anode electrode and a cathode electrode and with stability with time improved. <P>SOLUTION: The device is provided with a discharge lamp La equipped with an airtight vessel 1 with gas as a discharge medium sealed in, an anode electrode 2a as well as a cathode electrode 2b arranged inside the airtight vessel 1, and a discharge plasma generating auxiliary device arranged inside the airtight vessel 1 and equipped with an electron source 10 supplying electrons into the gas above and a grid electrode 20 set in opposition to the electron source 10. A control means (not shown) is provided for appropriately putting on and off switches SW1 to SW3 so as to have discharge plasma generated between the anode electrode 2a and the cathode electrode 2b, after having preliminary discharge generated between the grid electrode 20 and the anode electrode 2a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge plasma apparatus using discharge plasma.

  Conventionally, a discharge plasma between discharge electrodes used in a discharge plasma device such as a light emitting device having an airtight container filled with a gas as a discharge medium and a pair of discharge electrodes arranged in the airtight container. As a discharge plasma generation auxiliary device that assists the generation of discharge plasma in the generation space, a field emission type electron source that supplies electrons into the gas is provided in the hermetic vessel, thereby reducing the discharge start voltage and maintaining the discharge plasma. It is known that effects such as voltage reduction and discharge plasma stabilization can be obtained (see, for example, Patent Document 1).

In addition, in the above-mentioned Patent Document 1, as an application example of the discharge plasma generation auxiliary device, in addition to a plasma display panel provided with a phosphor layer that emits light by being excited by ultraviolet rays generated by discharge plasma on the inner surface of an airtight container. Application to ultraviolet lamps, fluorescent lamps and the like is described. In Patent Document 1, a Spindt-type electron source is obtained by using a planar electron source such as a ballistic electron surface-emitting device (BSD) or an MIM electron source as an electron source. It is described that it is less susceptible to ion bombardment than when it is used.
JP 2002-150944 A

  However, depending on the conditions such as the type and pressure of the gas sealed in the hermetic container of the discharge plasma apparatus and the interval between the discharge electrodes, the discharge start voltage is very high. It may be difficult to start discharge at a low voltage. Therefore, it is conceivable that a preliminary discharge is generated in the vicinity of the plasma generation space between the discharge electrodes, and the generation of discharge plasma between the discharge electrodes is induced by a large amount of electrons generated by the preliminary discharge.

  By the way, a conventionally known high pressure mercury lamp includes an auxiliary electrode (preliminary discharge electrode) disposed in the vicinity of one main electrode of a pair of main electrodes (discharge electrodes). A lighting system is adopted in which a glow discharge (preliminary discharge) is generated between the main electrode and the auxiliary electrode, and the arc discharge is performed between the main electrodes. However, in a xenon lamp that does not use mercury, one of the main electrodes Even a preliminary discharge between the electrode and the auxiliary electrode may be difficult to occur.

  Here, an electron source for supplying electrons to a space (preliminary discharge region) between one main electrode and auxiliary electrode of a pair of main electrodes (anode electrode, cathode electrode) in an airtight container of a xenon lamp. It is conceivable to reduce the discharge start voltage of the preliminary discharge by arranging and supplying electrons to the preliminary discharge region before applying a voltage between the one main electrode and the auxiliary electrode.

  However, in such a xenon lamp, there is a concern that the electron source is exposed to the discharge plasma and damaged by ion bombardment, and the lifetime of the electron source is shortened and the reliability is lowered. Here, if an electron source is a planar electron source such as the above-mentioned BSD or MIM type electron source or a hot cathode, it is more affected by ion bombardment than an electron source such as a Spindt type electron source. Although it becomes difficult, it is necessary to avoid that the electron source is directly exposed to the discharge plasma in terms of stability over time.

  The present invention has been made in view of the above-described reasons, and an object of the present invention is to provide a discharge plasma apparatus capable of reducing a discharge start voltage between an anode electrode and a cathode electrode and improving stability over time. .

  According to the first aspect of the present invention, there is provided an airtight container in which a gas as a discharge medium is sealed, an anode electrode and a cathode electrode disposed in the airtight container, an electron source disposed in the airtight container and supplying electrons into the gas. And a discharge plasma generation assisting device having a grid electrode disposed opposite to the electron source and assisting generation of discharge plasma in a discharge plasma generation space between the anode electrode and the cathode electrode, the grid electrode and the anode electrode, A control means for generating discharge plasma between the anode electrode and the cathode electrode after the preliminary discharge is generated between the anode electrode and the cathode electrode is provided.

  According to the present invention, the control means for generating the discharge plasma between the anode electrode and the cathode electrode after the preliminary discharge is generated between the grid electrode and the anode electrode is provided. The discharge start voltage between the electrodes can be reduced, and the preliminary discharge is generated between the grid electrode and the anode electrode, so that it is possible to prevent the electron source from being directly exposed to the discharge plasma of the preliminary discharge and to be stable over time. Can be improved.

  According to a second aspect of the present invention, in the first aspect of the present invention, the electric field strength between the anode electrode and the grid electrode is larger than the electric field strength between the grid electrode and the electron source. A potential difference between the grid electrode and the electron source and a potential difference between the anode electrode and the grid electrode are set.

  According to the present invention, the electric field strength between the anode electrode and the grid electrode is larger than the electric field strength between the grid electrode and the electron source. When generating predischarge plasma between the grid electrode and the electron source, it is possible to prevent unnecessary discharge from occurring, and the electron source is exposed to the discharge plasma and damaged. Can be prevented, and stability over time can be improved.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the anode is arranged so that a discharge is more likely to occur between the anode electrode and the grid electrode than between the grid electrode and the electron source. An interval between the electrode and the grid electrode and an interval between the grid electrode and the electron source are set. If the space pressure is p and the interval is d, the ease of discharge is determined by the value of p × d according to Paschen's law.

  According to the present invention, unnecessary discharge plasma can be prevented from being generated between the grid electrode and the electron source, and the electron source can be prevented from being damaged by the unnecessary discharge plasma. be able to.

  According to a fourth aspect of the present invention, there is provided an airtight container in which a gas as a discharge medium is sealed, an anode electrode and a cathode electrode disposed in the airtight container, an electron source disposed in the airtight container and supplying electrons into the gas. And a discharge plasma generation auxiliary device for assisting generation of discharge plasma in the discharge plasma generation space between the anode electrode and the cathode electrode having a grid electrode disposed opposite to the electron source, the electron source side of the grid electrode And a control means for generating a discharge plasma between the anode electrode and the cathode electrode after the preliminary discharge is generated between the grid electrode and the preliminary discharge electrode. And is provided.

  According to the present invention, the preliminary discharge electrode disposed opposite to the side opposite to the electron source side in the grid electrode and the anode electrode and the cathode after the preliminary discharge is generated between the grid electrode and the preliminary discharge electrode Since a control means for generating discharge plasma is provided between the electrode and the electrode, the discharge start voltage between the anode electrode and the cathode electrode can be reduced, and the preliminary discharge is performed between the grid electrode and the preliminary discharge electrode. Therefore, it is possible to prevent the electron source from being directly exposed to the discharge plasma of the preliminary discharge, improve the stability over time, and increase the degree of freedom in designing the layout of the discharge plasma generation auxiliary device in the hermetic vessel. .

  According to a fifth aspect of the present invention, in the invention of the fourth aspect, the grid electrode and the preliminary discharge electrode are formed in the discharge plasma generation space in a direction crossing a direction in which the anode electrode and the cathode electrode are arranged. It is arranged on both sides.

  According to the present invention, the preliminary discharge between the grid electrode and the preliminary discharge electrode is generated in a part of the discharge plasma generation space between the anode electrode and the cathode electrode. Since the generated electrons and cations are efficiently supplied to the discharge plasma generation space, the discharge start voltage between the anode electrode and the cathode electrode can be reduced, and between the anode electrode and the cathode electrode It becomes possible to generate the discharge plasma more reliably.

  According to the first and fourth aspects of the invention, there is an effect that the discharge start voltage between the anode electrode and the cathode electrode can be reduced and the stability over time can be improved.

(Embodiment 1)
As shown in FIG. 1, the discharge plasma apparatus of the present embodiment includes an airtight container 1 in which a gas (for example, a rare gas such as Xe) as a discharge medium is sealed, and an anode electrode disposed inside the airtight container 1. The discharge lamp La is provided with 2a and a cathode electrode 2b, an electron source 10 that is arranged in the hermetic container 1 and supplies electrons into the gas, and a grid electrode 20 that is arranged to face the electron source 10.

  The grid electrode 20 is provided for accelerating electrons emitted from the electron source 10, and has a plurality of openings 22a through which the electrons emitted from the electron source 10 pass. Then, the electron source 10 and the grid electrode 20 constitute a discharge plasma generation assisting device that assists the generation of discharge plasma in the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b.

Further, the discharge plasma apparatus of the present embodiment includes a discharge power source V _AK that supplies a DC voltage for discharge between the anode electrode 2a and the cathode electrode 2b with the anode electrode 2a on the high potential side, and an electron source 10 described later. a drive power supply V _PS supplies a DC voltage for driving the surface electrode 17 as a high-potential side between the surface electrode 17 and the lower electrode 15, between the surface electrode 17 of the grid electrode 20 and the electron source 10 a power source V _G supplies a DC voltage to the grid electrode 20 as the high potential side, a switch SW1 is inserted into the electric path between the discharge power supply V _AK and the anode electrode 2a, and the drive power supply V _PS and the surface electrode 17 a switch SW2 that is inserted into path between a switch SW3 inserted path between a power source _{V G} and the grid electrode 20, and controls on and off of the switches SW1, SW2, SW3 Lee black and a control unit comprising a computer (not shown).

  The discharge lamp La in the present embodiment is a straight tube type discharge lamp, and the hermetic vessel 1 is formed in a cylindrical shape from a light-transmitting material (for example, glass, light-transmitting ceramic, etc.) and has one end in the longitudinal direction. The anode electrode 2a is disposed at the portion (the right end portion in FIG. 1), the cathode electrode is disposed at the other end portion in the longitudinal direction (the left end portion in FIG. 1), and the discharge plasma generation auxiliary device is in the vicinity of the anode electrode 2a. (In short, the electron source 10 and the grid electrode 20 are disposed outside the discharge plasma generation space 3 in the hermetic vessel 1. Note that the discharge lamp La in the present embodiment is a phosphor layer (not shown) that emits light by being excited by ultraviolet rays generated by the excitation of Xe gas on the inner surface of the hermetic vessel 1. It is provided, but the phosphor layer is not necessarily provided, if not provided with the phosphor layer, so that the ultraviolet light and visible light generated by excitation of Xe gas is emitted through the airtight container 1.

  As shown in FIGS. 1 and 2, the electron source 10 includes a metal film (for example, a rectangular plate-like insulating substrate (for example, an insulating glass substrate, an insulating ceramic substrate) 14 on one surface. , A tungsten film, etc.), a strong electric field drift layer 16 is formed on the lower electrode 15, and a surface electrode 17 made of a conductive thin film (for example, a gold thin film) is formed on the strong electric field drift layer 16. Is formed. Although the thickness of the conductive thin film constituting the surface electrode 17 is desirably set to about 10 to 15 nm, the conductive thin film is not limited to a single layer film but may be a multilayer film.

  In the electron source 10 in the present embodiment, the strong electric field drift layer 16 constitutes an electron passage layer, and electrons are emitted through the surface electrode 17 by the lower electrode 15, the strong electric field drift layer 16 serving as the electron passage layer, and the surface electrode 17. The electron source element 10a is configured.

  As shown in FIG. 3, the strong electric field drift layer 16 of the electron source element 10 a includes at least columnar polycrystalline silicon grains (semiconductor crystals) 51 arranged on the surface side of the lower electrode 15, and the surface of the grain 51. A thin silicon oxide film 52 formed on the surface, a number of nanometer order silicon microcrystals (semiconductor microcrystals) 63 interposed between the grains 51, and a crystal of the silicon microcrystal 63 formed on the surface of each silicon microcrystal 63. It is composed of a large number of silicon oxide films 64 which are insulating films having a film thickness smaller than the grain size. Here, each grain 51 extends in the thickness direction of the lower electrode 15 (that is, extends in the thickness direction of the insulating substrate 14).

In order to emit electrons from the above-described electron source element 10a, a driving voltage is applied between the surface electrode 17 and the lower electrode 15 by the driving power source _VPS so that the surface electrode 17 is on the high potential side with respect to the lower electrode 15. When applied, electrons injected from the lower electrode 15 into the strong electric field drift layer 16 drift through the strong electric field drift layer 16 and are emitted through the surface electrode 17.

  Here, in the electron source element 10a in the present embodiment, electrons can be emitted even when the driving voltage applied between the surface electrode 17 and the lower electrode 15 is a low voltage of about 10 to 20V. The electron source element 10a of the present embodiment is characterized in that the electron emission characteristics are less dependent on the degree of vacuum, and a popping phenomenon does not occur during electron emission, and electrons can be stably emitted with high electron emission efficiency. Have.

The basic configuration of the electron source element 10a in this embodiment is well known, and it is considered that electron emission occurs in the following model. That is, electrons e ⁻ are injected from the lower electrode 15 into the strong electric field drift layer 16 by applying a voltage between the surface electrode 17 and the lower electrode 15 with the surface electrode 17 at the high potential side. On the other hand, since most of the electric field applied to the strong electric field drift layer 16 is applied to the silicon oxide film 64, the injected electrons e ⁻ are accelerated by the strong electric field applied to the silicon oxide film 64, and the strong electric field drift layer 16. 3 drifts toward the surface in the direction of the arrow in FIG. 3 (upward in FIG. 3), tunnels through the surface electrode 17 and is emitted. Thus, in the strong electric field drift layer 16, electrons injected from the lower electrode 15 are almost scattered by the silicon microcrystal 63 and are accelerated and drifted by the electric field applied to the silicon oxide film 64 and emitted through the surface electrode 17. Thus, since the heat generated in the strong electric field drift layer 16 is dissipated through the grains 51, no popping phenomenon occurs during electron emission, and electrons can be stably emitted.

  In the electron source 10 described above, the surface electrode 17 constitutes an electron emission portion. Further, in the above-described strong electric field drift layer 16, the silicon oxide film 64 constitutes an insulating film, and an oxidation process is employed for forming the insulating film, but a nitriding process or an oxynitriding process is employed instead of the oxidation process. Alternatively, when the nitriding process is adopted, each of the silicon oxide films 52 and 64 becomes a silicon nitride film, and when the oxynitriding process is adopted, each of the silicon oxide films 52 and 64 is silicon oxynitride. Become a film.

  The grid electrode 20 described above is formed in a net-like shape from a conductive material (for example, nickel, aluminum, stainless steel, etc.), and each part of the net-like net is a portion of electrons emitted from the electron source 10. An opening 20a is formed.

  As the grid electrode 20 described above, a nickel mesh having a side of a square mesh of 0.6 mm and a wire diameter of 0.25 mm, which is called 30 mesh, is used. The size, that is, the size of the opening 20a is not particularly limited, as long as the electrons emitted from the electron source 10 can pass through and the intrusion of ions from the discharge plasma generated in the discharge plasma generation space 3 can be suppressed. For example, the length of one side of the square opening 20a may be set as appropriate within a range of about 0.1 mm to 2 mm. In the present embodiment, the grid electrode 20 is formed in a net-like shape. However, the grid electrode 20 is not limited to the net-like shape, and is, for example, a flat plate-like conductive base material and the surface of the electron source 10. An opening having the same shape as that of the surface electrode 17 may be provided in a portion facing the electrode 17.

In a discharge plasma apparatus of the present embodiment, by driving the discharge plasma generating assist device, i.e., the surface electrode 17 and the lower electrode of the electron source 10 from the driving power source V _PS by turning on the switch SW2, SW3 by the control means by applying a DC voltage for acceleration between the grid electrode 20 and the surface electrode 17 from the power supply V _G is applied with a DC voltage for driving between 15, electrons grid emitted from the electron source 10 It is accelerated by the electrode 20 and supplied to the space between the anode electrode 2a and the grid electrode 20 (hereinafter referred to as a preliminary discharge region). Here, if the switch SW1 is turned on by the control means, an electric field determined by the potential difference between the anode electrode 2a and the grid electrode 20 and the distance between the anode electrode 2a and the grid electrode 20 is between the anode electrode 2a and the grid electrode 20. The electrons supplied to the preliminary discharge region are accelerated by the electric field between the anode electrode 2a and the grid electrode 20 and collide with gas molecules existing in the preliminary discharge region to knock out the electrons. Is repeated, the current flowing between the anode electrode 2a and the grid electrode 20 increases, and preliminary discharge occurs. In this way, by supplying the initial electrons necessary for starting the discharge between the anode 2a and the grid electrode 20 from the electron source 10 to the preliminary discharge region, the discharge between the anode 2a and the grid electrode 20 is started. The voltage can be reduced.

  In the discharge plasma apparatus according to the present embodiment, a large amount of electrons and cations generated in the preliminary discharge region between the anode electrode 2a and the grid electrode 20 generate a discharge plasma generation space between the anode electrode 2a and the cathode electrode 2b. The electrons supplied to the discharge plasma generation space 3 are accelerated by the electric field between the anode electrode 2a and the cathode electrode 2b, collide with gas molecules existing in the discharge plasma generation space 3, and knock out the electrons. By repeating this process, the current flowing between the anode electrode 2a and the cathode electrode 2b increases, and discharge plasma is generated. Further, there also occurs a process in which electrons and cations generated between the anode electrode 2a and the grid electrode 20 directly excite gas molecules present in the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b.

In the discharge plasma apparatus of the present embodiment described above, the control unit generates a discharge plasma between the anode electrode 2a and the cathode electrode 2b after generating a preliminary discharge between the grid electrode 20 and the anode electrode 2a. Since the switches SW1 to SW3 are controlled so as to be generated, the discharge start voltage between the anode electrode 2a and the cathode electrode 2b can be reduced, and the preliminary discharge is generated between the grid electrode 20 and the anode electrode 2a. Further, it is possible to prevent the electron source 10 from being directly exposed to the discharge plasma of the preliminary discharge, and to improve the stability over time. Note that after the discharge plasma is generated in the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b, the switches SW2 and SW3 are turned off by the control means, so that the power consumption can be reduced and the electrons can be reduced. The life of the source 10 can be extended. In this embodiment, the switches SW1 to SW3 are appropriately turned on and off by the control means. Instead of providing the switches SW1 to SW3, the power supplies V _AK , V _PS , and V _G are provided by the control means. By controlling the output voltage, discharge plasma may be generated between the anode electrode 2a and the cathode electrode 2b after the preliminary discharge is generated between the grid electrode 20 and the anode electrode 2a. In the present embodiment, the control means applies a voltage between the anode electrode 2a and the cathode electrode 2b after applying a voltage between the anode electrode 2a and the grid electrode 20, whereby the grid electrode After a preliminary discharge is generated between the anode electrode 2a and the anode electrode 2a, a discharge plasma is generated between the anode electrode 2a and the cathode electrode 2b, but between the anode electrode 2a and the cathode electrode 2b. By applying a voltage between the anode electrode 2a and the grid electrode 20 after applying the voltage, a preliminary discharge is generated between the grid electrode 20 and the anode electrode 2a, and then the anode electrode 2a and the cathode electrode A discharge plasma may be generated between 2b.

  By the way, in this embodiment, the grid electrode 20, the electron source 10, and the electric field strength between the anode electrode 2a and the grid electrode 20 are larger than the electric field strength between the grid electrode 20 and the electron source 10. The potential of each anode electrode 2a is set. As an example, the distance between the grid electrode 20 and the surface electrode 17 of the electron source 10 is 4 mm, the distance between the anode electrode 2a and the grid electrode 20 is 3 mm, the potential of the surface electrode 17 of the electron source 10 is 0 V, The potential is 60V, and the potential of the anode electrode 2a is 300V or more.

  Therefore, in the discharge plasma apparatus of the present embodiment, the electric field strength between the anode electrode 2a and the grid electrode 20 is larger than the electric field strength between the grid electrode 20 and the electron source 10, and therefore the anode electrode 2a When the discharge plasma of the preliminary discharge is generated between the grid electrode 20 and the grid electrode 20, it is possible to suppress unnecessary discharge from occurring between the grid electrode 20 and the electron source 10, and the surface electrode 17 of the electron source 10 is discharged. It can be prevented from being damaged by being exposed to plasma, and stability over time can be improved.

  In the discharge plasma apparatus of the present embodiment, the anode electrode 2a and the grid are arranged so that the discharge is more likely to occur between the anode electrode 2a and the grid electrode 20 than between the grid electrode 20 and the surface electrode 17 of the electron source 10. The distance between the electrode 20 and the distance between the grid electrode 20 and the surface electrode 17 of the electron source 10 are set. Here, the ease of discharge is determined by a value of p × d according to Paschen's law, where p is the space pressure and d is the interval. When Xe gas is used as the discharge gas as in the present embodiment, discharge is most likely to occur when p [Pa] × d [m] = 1. In this embodiment, since the pressure of the Xe gas is set to 1 kPa, discharge is more likely to occur as d is closer to 1 mm. However, as described above, the distance between the grid electrode 20 and the surface electrode 17 of the electron source 10. 4 mm, and the distance between the anode electrode 2 a and the grid electrode 20 is set to 3 mm. Therefore, the gap between the grid electrode 20 and the surface electrode 17 of the electron source 10 is between the anode electrode 2 a and the grid electrode 20. Therefore, it is possible to prevent unnecessary discharge plasma from being generated between the grid electrode 20 and the surface electrode 17 of the electron source 10, and the unnecessary discharge plasma causes electrons to be generated. The source 10 can be prevented from being damaged.

(Embodiment 2)
The basic configuration of the discharge plasma apparatus of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 4, as shown in FIG. 4, the preliminary discharge electrode 30 disposed opposite to the electron source 10 side of the grid electrode 20 A power source V ₄ for supplying a DC voltage between the pre-discharge electrode 30 and the lower electrode 15 of the electron source 10 with the pre-discharge electrode 30 as a high potential side, and between the power source V ₄ and the pre-discharge electrode 30 and a switch SW4 which is inserted into electrical path, that power V _G is connected to a DC voltage is applied between the lower electrode 15 of the grid electrode 20 and the electron source 10, described in embodiment 1 Instead of the control means, a control means for generating a discharge plasma between the anode electrode 2a and the cathode electrode 2b after the preliminary discharge is generated between the grid electrode 20 and the preliminary discharge electrode 30 is provided. etc To differences. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  The preliminary discharge electrode 30 is formed in a net-like shape similar to the grid electrode 20, but is not limited to the net-like shape, and may be, for example, a shape in which an opening is provided in a flat conductive base material, It may be a wire shape.

In a discharge plasma apparatus of the present embodiment, by driving the discharge plasma generating assist device, i.e., the surface electrodes 17 of the electron source 10 from the driving power source V _PS by turning on the switch SW2, SW3, SW4 by the control means and DC voltage for acceleration between the grid electrode 20 and the lower electrode 15 from the power supply V _G is applied with a DC voltage for driving is applied between the lower electrode 15, the preliminary discharge electrode 30 further from the power supply V ₄ By applying a DC voltage for preliminary discharge between the electrode 15 and the lower electrode 15, electrons emitted from the electron source 10 are accelerated by the grid electrode 20, and a space between the grid electrode 20 and the preliminary discharge electrode 30 is obtained. (Hereinafter referred to as a preliminary discharge region). Here, when the switch SW1 is turned on by the control means, the electric field determined by the potential difference between the preliminary discharge electrode 30 and the grid electrode 20 and the interval between the preliminary discharge electrode 30 and the grid electrode 20 is Since it is applied between the grid electrode 20, the electrons supplied to the preliminary discharge region are accelerated by the electric field between the preliminary discharge electrode 30 and the grid electrode 20, and become gas molecules existing in the preliminary discharge region. By repeating the process of colliding and knocking out electrons, the current flowing between the preliminary discharge electrode 30 and the grid electrode 20 increases, and preliminary discharge occurs. Thus, by supplying the initial electrons necessary for starting the discharge between the preliminary discharge electrode 30 and the grid electrode 20 from the electron source 10 to the preliminary discharge region, the preliminary discharge electrode 30 and the grid electrode 20 The discharge start voltage can be reduced.

  Therefore, in the discharge plasma apparatus of the present embodiment, the preliminary discharge electrode 30 disposed opposite to the side opposite to the electron source 10 side of the grid electrode 20 and the preliminary discharge electrode 30 is provided between the grid electrode 20 and the preliminary discharge electrode 30. Since control means for controlling the switches SW1 to SW4 is provided so as to generate discharge plasma between the anode electrode 2a and the cathode electrode 2b after the discharge is generated, the anode electrode 2a and the cathode electrode 2b In addition, since the pre-discharge is generated between the grid electrode 20 and the pre-discharge electrode 30, it is possible to prevent the electron source 10 from being directly exposed to the pre-discharge plasma. Thus, the stability over time can be improved, and the degree of freedom in the layout design of the discharge plasma generation auxiliary device in the hermetic vessel 1 is increased. Not limited to be disposed between the electrode 2a and the cathode electrode 2b, or be located close to the anode electrode 2a as in the embodiment 1, it is possible to or placed close to the cathode electrode 2b.

  Further, in the discharge plasma apparatus according to the present embodiment, the grid electrode 20 and the preliminary discharge electrode 30 are arranged in the discharge plasma generation space 3, and therefore generated by the preliminary discharge between the grid electrode 20 and the preliminary discharge electrode 30. Since the generated electrons are efficiently supplied to the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b, the discharge start voltage between the anode electrode 2a and the cathode electrode 2b can be reduced, and the anode electrode 2a It becomes possible to generate discharge plasma more reliably in the discharge plasma generation space 3 between the cathode electrode 2b.

In the present embodiment, the switches SW1 to SW4 are appropriately turned on and off by the control means. However, instead of providing the switches SW1 to SW4, the power supplies V _AK , V _PS , V _G , By controlling the output voltage of each V ₄ , a discharge plasma is generated between the anode electrode 2 a and the cathode electrode 2 b after a preliminary discharge is generated between the grid electrode 20 and the preliminary discharge electrode 30. It may be. In the present embodiment, the control means applies a voltage between the anode electrode 2 a and the cathode electrode 2 b after applying a voltage between the grid electrode 20 and the preliminary discharge electrode 30. After a preliminary discharge is generated between the electrode 20 and the preliminary discharge electrode 30, a discharge plasma is generated between the anode electrode 2a and the cathode electrode 2b. The anode electrode 2a and the cathode electrode 2b After generating a preliminary discharge between the grid electrode 20 and the preliminary discharge electrode 30 by applying a voltage between the grid electrode 20 and the preliminary discharge electrode 30 after applying a voltage between Thus, a discharge plasma may be generated between the anode electrode 2a and the cathode electrode 2b.

(Embodiment 3)
The basic configuration of the discharge plasma apparatus according to the present embodiment is substantially the same as that of the second embodiment, and the grid electrode 20 and the preliminary discharge electrode 30 intersect with the direction in which the anode electrode 2a and the cathode electrode 2b are aligned. The only difference is that they are arranged on both sides of the discharge plasma generation space 3. In short, the present embodiment is different in that the grid electrode 20 and the preliminary discharge electrode 30 are arranged so as to sandwich the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b. . In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 2, and description is abbreviate | omitted.

  Thus, in the discharge plasma apparatus of the present embodiment, the preliminary discharge between the grid electrode 20 and the preliminary discharge electrode 30 is generated in a part of the discharge plasma generation space 3 between the anode electrode 2a and the cathode electrode 2b. Therefore, since electrons and cations generated in the preliminary discharge are efficiently supplied to the discharge plasma generation space 3, the discharge start voltage between the anode electrode 2a and the cathode electrode 2b can be reduced and the anode electrode 2a and the cathode electrode can be reduced. It becomes possible to generate discharge plasma more reliably between 2b.

  By the way, in each of the embodiments described above, BSD is used as the electron source 10, but the electron source 10 is not limited to BSD, but is an MIM type electron source, a Spindt type electron source, or an electron using a carbon nanotube. A source, a hot cathode, or the like may be employed. However, electron sources other than BSD have a low electron energy of 1 eV or less when emitted, whereas BSD has a high electron energy of several eV or more. Therefore, by adopting BSD as the electron source 10, the effect of ionizing gas molecules is enhanced, and the discharge start voltage can be further reduced.

  In each of the above embodiments, a discharge lamp using Xe gas is exemplified as the discharge plasma apparatus. However, the present invention is not limited to the discharge lamp, and for example, a fluorescent lamp for illumination or a plasma display panel may be used.

Further, in the light emitting device in each of the above embodiments, Xe gas is adopted as the gas sealed in the hermetic container 1, but the gas sealed in the hermetic container 1 is not limited to Xe gas. Any gas that causes discharge by supplying energy such as He gas, Ne gas, Ar gas, Kr gas, N ₂ gas, CO gas, Hg vapor, or a mixed gas thereof may be used.

It is a schematic block diagram of the discharge plasma apparatus of Embodiment 1. It is a schematic sectional drawing of the discharge plasma production auxiliary | assistance apparatus used for the same as the above. It is operation | movement explanatory drawing of the electron source used for the same as the above. It is a schematic block diagram of the discharge plasma apparatus of Embodiment 2. It is a schematic block diagram of the discharge plasma apparatus of Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 2a Anode electrode 2b Cathode electrode 3 Discharge plasma production space 10 Electron source 20 Grid electrode La Discharge lamp

Claims (5)

  An airtight container in which a gas as a discharge medium is sealed, an anode electrode and a cathode electrode disposed in the airtight container, an electron source disposed in the airtight container and supplying electrons into the gas, and an electron source. A discharge plasma generation auxiliary device that assists the generation of discharge plasma in the discharge plasma generation space between the anode electrode and the cathode electrode and generates a preliminary discharge between the grid electrode and the anode electrode And a control means for generating discharge plasma between the anode electrode and the cathode electrode.   The potential difference between the grid electrode and the electron source and the anode electrode so that the electric field strength between the anode electrode and the grid electrode is larger than the electric field strength between the grid electrode and the electron source. The discharge plasma apparatus according to claim 1, wherein a potential difference from the grid electrode is set.   The distance between the anode electrode and the grid electrode and the distance between the grid electrode and the electron source so that the discharge is more likely to occur between the anode electrode and the grid electrode than between the grid electrode and the electron source. The discharge plasma apparatus according to claim 1 or 2, wherein an interval is set.   An airtight container in which a gas as a discharge medium is sealed, an anode electrode and a cathode electrode disposed in the airtight container, an electron source disposed in the airtight container and supplying electrons into the gas, and an electron source. A discharge plasma generation auxiliary device that assists the generation of discharge plasma in the discharge plasma generation space between the anode electrode and the cathode electrode, and is opposed to the electron source side of the grid electrode. And a control means for generating discharge plasma between the anode electrode and the cathode electrode after the preliminary discharge is generated between the grid electrode and the preliminary discharge electrode. A discharge plasma apparatus characterized by the above.   5. The grid electrode and the preliminary discharge electrode are arranged on both sides of the discharge plasma generation space in a direction crossing a direction in which the anode electrode and the cathode electrode are arranged. The discharge plasma apparatus described.

Images