JP3069047B2 - Discharge lamp electrode and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp electrode which can be used for a fluorescent lamp such as a backlight for liquid crystal or various discharge lamps, and a method of manufacturing the same.

2. Description of the Related Art In recent years, a demand for a liquid crystal display that can be reduced in power consumption and reduced in weight has been rapidly spreading.
Along with this, small fluorescent lamps as light sources for liquid crystal displays have been actively developed. Generally, fluorescent lamps can be classified into hot cathode lamps using arc discharge due to thermionic emission and cold cathode lamps using glow discharge due to secondary electron emission. Since the hot cathode lamp has a smaller cathode drop voltage than the cold cathode lamp, the luminous efficiency with respect to electric power is good. In addition, the current density can be increased due to thermionic electron emission, and higher brightness can be achieved as compared with the cold cathode. Therefore, the hot cathode lamp is suitable as a light source when a large amount of light is required, such as a liquid crystal having a large screen size. An electrode for such a hot cathode lamp is disclosed in
In a tungsten (W) filament as disclosed in JP-A-9-75553, a part of a transition metal and barium (B)
Discharge lamp electrodes coated with an alkaline earth metal containing a) are known. Further, as disclosed in JP-A-63-24539, an electrode is known in which porous tungsten is impregnated with an electron-emitting material containing barium aluminate.

However, as described above, as the liquid crystal display device becomes thinner and lighter, there is an increasing demand for a fluorescent lamp as a light source to be made thinner.
For this reason, in a structure requiring a preheating circuit (preheating electrode) to start thermionic emission such as a conventional hot cathode lamp, it has been difficult to make the tube as thin as a cold cathode lamp. Further, as another problem of the conventional hot cathode lamp, mercury (Hg) ions or argon (Ar) ions generated during discharge collide with the electrodes and scatter the electron-emitting substance. there were. For this reason,
During the discharge, the electron-emitting material is depleted, and a stable arc discharge cannot be maintained for a long time. Further, there is a drawback that the inner wall of the glass tube of the lamp is blackened by the scattered electron-emitting material, that is, the so-called blackening of the tube wall causes the luminous flux maintenance factor to be reduced early. As a means for solving these problems, the present inventors have disclosed Japanese Patent Application Laid-Open No. 2-186550.
As shown in Japanese Unexamined Patent Application Publication No. Hei 6-267404,
We proposed a discharge electrode material (electron-emitting substance), its manufacturing method and electrode structure. These had excellent properties in thermal shock resistance, but as shown in FIGS. 6 (a) and 6 (b).
Due to the structure in which a simple bottomed cylindrical conductive electrode container contains a massive or granular discharge electrode material that becomes an electron-emitting substance, the massive or granular discharge electrode material may fall off during discharge. In addition, when used as a fluorescent lamp, a transition from arc discharge to glow discharge occurs due to a shortage of an electron-emitting substance during lighting, and the life as a hot cathode was not extended so much and was insufficient. Accordingly, an object of the present invention is to provide a discharge lamp electrode capable of prolonging a continuous lighting life by preventing the aggregate type structure filling from falling off and stably maintaining an arc discharge, and a method of manufacturing the same. The aggregate-type structure is described in “Porous Material Handbook” (IPC Publishing Co., Ltd., December 1988).
(Issued on January 1), there are solid particles such as sintered metal and refractory bricks, which have a porous structure formed by sintering and solidifying at the points of contact with each other. is there. The schematic diagram is shown in FIG. Here, the aggregate-type structured filler of the present invention refers to a filler of an aggregate-type structured electron-emitting substance formed by filling an electrode container with a massive or granular electron-emitting substance and firing the same. It is.

A first component comprising a compound containing at least one of Ba, Sr, and Ca;
A second component comprising a compound containing Zr and / or Ti;
An aggregate-type structured packing made of an electron-emitting substance containing a third component made of a compound containing Ta and / or Nb is provided, and the packing is contained in an electrode container. The container has a bottom cylindrical shape, and the container has a storage portion for storing the filler therein.
Has a support for supporting the aggregate-type structured packing
And the support portion is provided on an inner bottom surface of the bottomed cylinder and / or
Numeral denotes a projection protruding from the inner surface to the inside of the housing portion, which is a discharge lamp electrode in which the surface area of the housing portion is larger than the surface area of the inner wall of a simple bottomed cylinder. Further, the electrode container is a discharge lamp electrode made of a conductive high melting point metal or a ceramic having a conductive surface or entire surface when fired in a reducing atmosphere. Further, the housing portion and / or the support portion may include a first component made of a compound containing at least one of Ba, Sr, and Ca;
a second component comprising a compound containing r and / or Ti;
It is a discharge lamp electrode made of a material containing a third component made of a compound containing a and / or Nb. More specifically, when the first component is X, the second component is Y, and the third component is Z, the electron-emitting substance has a molar ratio of 0.8 ≦ X / (Y
+ Z) ≦ 2.0, the second component is 0.05 mol ≦ Y ≦ 0.6 mol, and the third component is 0.4
It is a discharge lamp electrode where mol ≦ Z ≦ 0.95 mol. Further, the present invention is a discharge lamp electrode in which a sputtering prevention layer of a carbide or a nitride of Ta or Nb is formed on a surface of the electron emitting material. A first component comprising a compound containing at least one of Ba, Sr, and Ca;
A second component comprising a compound containing Zr and / or Ti;
An aggregate-type structured packing made of an electron-emitting substance containing a third component made of a compound containing Ta and / or Nb is provided, and the packing is accommodated in an electrode container. The electrode container has a bottomed cylindrical shape. A container for accommodating the filler therein, wherein the container comprises an aggregate.
A support for supporting the mold structure packing;
The part is housed from the inner bottom surface and / or the inner side surface of the bottomed cylinder.
A protrusion protruding into the inside of the part, and the surface area of the accommodation part is
In a method of manufacturing a discharge lamp electrode having a larger surface area than the inner wall of a simple bottomed cylinder, the filler is mixed with a raw material comprising the first component, the second component, and the third component, and calcined. After crushing, the granulated powder is granulated, and the granulated powder is filled in an electrode container provided with a supporting portion, and fired in a reducing atmosphere to form a discharge lamp electrode having an aggregate-type structure filling. It is a method of manufacturing.

BEST MODE FOR CARRYING OUT THE INVENTION In a discharge lamp electrode according to the present invention, an electron-emitting substance which has been turned into an aggregate-type structure filling by firing is coated with an inner bottom surface and / or an inner bottom surface of a bottomed cylinder.
Since the electrode container is filled with an electrode container having a support having a protruding portion projecting from the surface into the inside of the accommodating portion , falling off of the electron-emitting substance is suppressed. Therefore, stable arc discharge can be maintained for a long period of time. (Fluorescent Lamp Using Discharge Lamp Electrode) A fluorescent lamp using the discharge lamp electrode container of the present invention will be described. FIG. 1A is a cross-sectional view of a fluorescent lamp tube end. FIG. 1B shows an enlarged view of a discharge lamp electrode. Reference numeral 9 denotes a bulb, which is formed of an elongated glass tube.
Although not shown, a fluorescent substance is applied to the inner wall of the bulb 9. Both ends of the bulb 9 are hermetically sealed by filling a rare gas, and a discharge space 10 is formed therein. Valve 9
Are formed at both ends thereof. At the tip of the lead wire 5 inside the bulb (discharge space side), there is a lead wire enlarged portion 6, which is one end of a conductive pipe 7 made of a material having high electrical conductivity such as a metal or a semiconductor ceramic. It is inserted at the end (tube end side).
In addition, the conductive electrode container 1 is inserted so as to be surrounded by the other end (discharge space side) of the conductive pipe 7. As a result, the lead wire 5 and the conductive electrode container 1 are electrically fixed. There is no particular problem if the material of the conductive pipe 7 is a material having a high electrical conductivity, but if the material is a material such as Ni which emits little gas in a vacuum, discharge is unstable due to generation of gas containing impurities during lamp production. It is preferable because it does not occur. The mercury dispenser material 3 is filled in a metal pipe 4 made of nickel (Ni) or the like, and is disposed between the enlarged portion 6 of the lead wire 5 and the conductive electrode container 1. As shown in the enlarged view of FIG.
Is formed with a slit-shaped opening 8 from the tip (discharge space side) to hold the conductive electrode container 1 so as to surround it and to heat the mercury in the mercury dispenser material 3 by high-frequency heating or the like so that the mercury vapor From the opening 8 to the discharge space 1
It is designed to be released to zero. The shape of the opening 8 may be any shape other than the slit shape, such as a window shape, as long as it can hold the conductive electrode container 1 and discharge the mercury vapor. Note that the enlarged portion 6 of the lead wire 5 is not always necessary. The conductive electrode container 1 contains an electron-emitting substance having an aggregate type structure, and constitutes a discharge lamp electrode according to the present invention. The discharge space 10 contains at least one of argon (Ar) gas, neon (Ne) gas, krypton (Kr) gas, and xenon (Xe) gas at 30 torr to 170 torr (ｒ3900P).
a to 22000 Pa).
Discharge is started by giving a potential difference between both electrodes through the lead wire 5. (Conductive Electrode Container) The conductive electrode container 1 containing the aggregate-type structure filling 2 which is the most characteristic structure of the present invention has an inner bottom surface and an inner bottom surface.
And / or has a substantially cylindrical shape with a bottom with a protruding process from the inner surface to the inside of the housing portion , and the inside is a housing portion for the electron-emitting substance. The storage portion may have a structure in which the surface area thereof is larger than that of the inner wall surface of a simple bottomed cylindrical shape so that the aggregate-type structured packing 2 can be securely held. For example, by providing irregularities, the surface area can be increased. This makes it difficult for the aggregate-type structure filling material 2 to fall off due to the discharge, and for the shortage of the electron-emitting substance to be less likely to occur, thereby extending the continuous lighting life. The material of the conductive electrode container 1 is preferably formed entirely of a material having high electrical conductivity such as W, Ta, Ni, etc., but is not limited to this. There is no particular problem if the substance is formed of a coated material. For example, a first component composed of a compound containing at least one of Ba, Sr, and Ca, and Zr and / or Ti
And a second component comprising a compound containing Ta and / or Nb.
A material containing a third component consisting of a compound containing If the material is close to the components of the aggregate-type structured filler 2 composed of an electron-emitting substance, the aggregate-type structured filler 2
This is more preferable because the contact between the storage portion of the conductive electrode container 1 that stores therein and the aggregate-type structure filling 2 becomes strong. The structure of the housing unit, may be provided for example supporting portion of the aggregate type structured packing 2, for example, the bottom surface and / or projections protruding from the inner surface inside the bottomed cylinder of the bottomed cylindrical, perforated
The inner wall of the bottom cylinder is provided with folds or irregularities having a roughened surface, or a combination of these, or the inner wall surface of the bottomed cylindrical vessel is made simple by various means. The structure is to be larger than the surface area. The support portion of the aggregate-type structure filler 2 may be formed so as to increase the surface area of the inner wall of the conductive electrode container 1. For example, a projection may be provided on the bottom surface and / or the inner wall of the conductive electrode container 1. However, the shape is not particularly limited as long as the surface area for supporting the aggregate-type structure filler 2 is large. This projection may be integrated with the main body of the conductive electrode container 1 or may be formed by making a hole in the bottomed cylindrical container and inserting the support. Since the conductive electrode container 1 is made of a conductive high-melting metal or ceramics whose surface or whole is made by firing in a reducing atmosphere, the projections themselves are also preferably conductive. It may be resistance.
Increasing the surface area for supporting the aggregate-type structure filler 2 increases the number of contact points with the electron-emitting substance, so that the aggregate-type structure filler 2 is prevented from falling off during discharge when sealed inside the lamp. Thus, the continuous lighting life can be extended as compared with a conventional simple bottomed cylindrical container having no support. (Aggregate-type structural filler (material for discharge lamp electrode)) An earlier application by the present inventors (1995 Patent Application No. 2810)
No. 02), specifically, Ba, S
Including a first component composed of a compound containing at least one of r and Ca, a second component composed of a compound containing Zr and / or Ti, and a third component composed of a compound containing Ta and / or Nb A material 2 composed of an electron-emitting substance is granulated, stored in an electrode container and fired to obtain a filling 2 having an aggregate structure. The composition of the main component of the filler is ABO3, for example, Ba (Z
r, Nb) O3, Ba (Zr, Ta) O3, Ba (T
i, Nb) O3, Ba (Ti, Ta) O3, Ba (Z
r, Nb, Ta) O3, Ba (Ti, Nb, Ta) O
3, Ba (Zr, Ti, Nb) O3, Ba (Zr, T
i, Ta) O3, Ba (Zr, Ti, Nb, Ta) O3
The composition may be composed of Sr and Ca instead of A site and Ba, and further an arbitrary combination of Ba, Sr and Ca. Further, on the surface of the filler 2, a sputtering prevention layer made of a carbide and / or nitride of Ta or Nb is formed. The first component is mainly a low work function emissive material. The second component is a component for increasing the melting point and lowering the electrical resistance of the electron-emitting substance, and the third component is a carbide and / or nitride for forming a sputtering prevention layer formed on the surface of the electron-emitting substance. Source. These first component, second component, and third component are each in a molar ratio,
0.8 ≦ X / (Y + Z) ≦ 2.0 (the first component is X, the second component is Y, and the third component is Z), and the second component is 0.05. ≦ Y ≦ 0.6, and the third component is preferably in the range of 0.4 ≦ Z ≦ 0.95. If the first component is less than the lower limit of the above range, the amount of the electron-emitting substance becomes insufficient, and it becomes impossible to turn on the light early. On the other hand, when the amount exceeds the upper limit of the above range, the evaporation of the electron-emitting substance becomes remarkable during the discharge, the blackening of the lamp tube wall becomes severe, and the luminance decreases, which is not preferable in practical use. When the second component is less than the lower limit of the above range, the electron-emitting substance has a low melting point, and during reduction firing,
The state of the aggregate-type structure filler 2 cannot be maintained, and the discharge becomes unstable. On the other hand, if it exceeds the upper limit of the above range, the resistance of the electron-emitting substance becomes high and the discharge becomes unstable. If the third component is less than the lower limit of the above range, it is difficult to form carbides or nitrides on the surface of the electron-emitting substance by firing in a reducing atmosphere. On the other hand, if it is more than the upper limit of the above range, evaporation of the electron-emitting substance becomes severe due to firing in a reducing atmosphere,
This is a manufacturing problem. The phase formed on the surface of the electron-emitting substance may be either carbide or nitride, and may be Ta-N
Solid solutions such as bC, Ta-NC, Ta-Nb-NC may be used. JP-A-6-333534 describes that an electrode for a high-pressure discharge lamp containing a carbide such as HfC has an effect of preventing blackening of a tube wall, but the discharge lamp electrode according to the present invention is described. Since the carbide and / or nitride on the surface of the electron-emitting substance are also resistant to ion sputtering and excellent in thermal shock, the blackening of the lamp tube wall during continuous lighting is small. Aggregate type structured packing 2
Is not limited to a spherical shape, and may be an irregular mass. Since the filler has an aggregate structure, heat is selectively accumulated in the aggregate structure filler portion. As a result,
As described in JP-A-7-296768, an arc spot is reliably formed and an arc discharge can be easily maintained. (Method of Manufacturing Discharge Lamp Electrode) The electrode is manufactured by the process shown in FIG. The entire manufacturing process can be performed in substantially the same manner as a general ceramics manufacturing method. (A) In the weighing step, each raw material is weighed so as to have a predetermined ratio as described above. Each raw material here is usually BaCO3, SrCO3, CaCO3, ZrO2, Ti
O2, Ta2O5, Nb2O5, or the like is used, but oxides, carbonates, oxalates, and the like other than those listed here may be used. (B) In the mixing step, the raw materials of the respective components weighed in the weighing step of step (a) are mixed to obtain a powder. Mixing is performed by a method such as a ball mill method, a freeze drying method, a friction mill method, and a coprecipitation method. (C) In the calcining step, the raw material powder mixed in the mixing step of the step (b) is calcined. 800 ℃ ～ 13
The temperature is set at about 00 ° C. to obtain a compound of an electron-emitting substance. At this time, the powder may be in the state of powder or in the state of molding the powder. (D) In the pulverizing step, the compound obtained in the calcining step in step (c) is pulverized. This is performed by a method such as a ball mill method. (E) In the granulation step, particles of an appropriate size are obtained from the fine particles obtained in the pulverization step of step (d). The powder obtained by the pulverization is granulated using an aqueous solution containing an organic binder such as polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene oxide (PEO) to obtain a granular raw material powder for an electron-emitting substance. . At this time, granulation is performed using a spray drying method, an extrusion granulation method, a tumbling granulation method, or a mortar or pestle, but the granulation method is not particularly limited. (F) In the filling step, the granulated electron-emitting substance raw material powder obtained in the granulation step in step (e) is filled in the electrode container described above to obtain an electrode element. At this time, the granular raw material powder for electron-emitting material is filled without applying pressure. When sintering after pressure molding like a sintered electrode, a sufficient heat storage effect cannot be obtained for thermionic emission, and a preheating circuit is used at the start of discharge. The arc discharge can be started quickly without using a preheating circuit by filling the electrode container with a suitable gap without pressurizing the granular material powder of the electron-emitting substance. (G) In the firing step, the electrode element obtained in the filling step in step (f) is fired to obtain a sintered body (discharge lamp electrode). The composition of the main component of the sintered body is ABO3, for example, Ba (Zr, Nb) O3, Ba (Zr, Ta) O
3, Ba (Ti, Nb) O3, Ba (Ti, Ta) O
3, Ba (Zr, Nb, Ta) O3, Ba (Ti, N
b, Ta) O3, Ba (Zr, Ti, Nb) O3, Ba
(Zr, Ti, Ta) O3, Ba (Zr, Ti, Nb,
Ta) O3 etc., but Sr,
A composition consisting of Ca, and further, any combination of Ba, Sr, and Ca may be used. The firing temperature of the electrode element filled with the granular raw material powder for electron emitting material is preferably 1400 to 2000 ° C. If the temperature is lower than 1400 ° C., a sputtering prevention layer made of carbide and / or nitride of Ta or Nb is not formed on the surface of the discharge lamp electrode. If the temperature exceeds 2000 ° C., the aggregate structure cannot be maintained. Regarding the firing atmosphere, for example, when a carbide is mainly formed on the surface of the discharge lamp electrode, firing is performed by flowing an inert gas such as argon or nitrogen containing benzene or carbon monoxide. Alternatively, the electrode element may be buried in carbon powder and fired by flowing an inert gas. When nitride is mainly formed on the surface of the discharge lamp electrode, firing is performed by flowing a nitrogen gas containing a reducing gas such as hydrogen or carbon monoxide. By firing in a reducing atmosphere in this manner, a sputtering prevention layer made of carbide or nitride of Ta or Nb is formed on the surface of the electron-emitting substance. Further, if the electrode container 1 has a support, the aggregate-type structure filling 2 is formed by firing, and the electron-emitting substance and the support react with each other to be partially connected. 2 hardly occurs, and the lamp operating life is extended.

Next, the present invention will be described in more detail by way of examples. Among the steps shown in the method for manufacturing a discharge lamp electrode described above, BaCO3, Sr is used in accordance with steps (a) to (e).
CO3, CaCO3, ZrO2, TiO2, Ta2O
5, an unfired granular raw material powder of electron-emitting material is prepared using Nb2O5 or the like as a starting material. An example is shown below, but the present invention is not limited to this, and as described above, the present inventors have filed an earlier application (1995 Patent Application No. 281002).
It is desirable to obtain the electron-emitting substance of (1). BaCO
3, ZrO2, Ta2O5 as starting material, BaCO3
After weighing 1.0 mol of ZrO2, 0.2 mol of ZrO2, and 0.8 mol of Ta2O5, the mixture was wet-mixed by a ball mill method for about 20 hours, and dried by a dryer at 80 to 130 ° C. And a molding pressure of about 100 MPa. This was calcined in the air at 800 to 1300 ° C. for about 2 hours. The obtained powder is pulverized for about 20 hours by a ball mill method, dried with a dryer at 80 to 130 ° C, added with an aqueous solution containing polyvinyl alcohol, granulated using a mortar and a pestle, and further obtained granules are obtained. A powder obtained by sieving the powder to have an average particle size of about 100 μm was used. Next, among the steps shown in the above-described method for manufacturing a discharge lamp electrode, an unfired granular electron-emitting substance raw material powder is filled in an electrode container according to steps (f) to (g) to prepare an electrode element. The electrode element is fired to complete the discharge lamp electrode. Example 1 FIG. 3A shows a front view of a discharge lamp electrode. FIG.
(B) is a cross-sectional view taken along line XX of (a) . In each case, the aggregate type structure is simply illustrated. The conductive electrode container 1 is provided with a projection 1 a projecting from the bottom of the bottomed cylinder . This makes it simpler
The surface area of the storage section is larger than that of
You. After filling the electrode container with granular electron-emitting substance raw material powder without applying pressure, this was buried in carbon powder and fired while flowing nitrogen to produce a discharge lamp electrode. The conductive electrode container 1 used at this time has a substantially cylindrical shape with a bottom and is projected from the bottom of the bottomed cylinder.
Pressed molding with a mold so as to have the protruding projection 1a, grinding the raw material powder into a block shape after molding with a mold, or machining into a bottomed cylindrical shape with a bottomed circle
A hole was made in the bottom of the tube, the support portion 1a was inserted, and the tube was fired. The shape of the conductive electrode container 1 is as follows. Outer diameter 2.3 mm Overall length 2.0 mm Housing inner diameter 1.5 mm Housing depth 1.5 mm Projection outer diameter 0.5 mm Projection overall length 1.2 mm (Example 2) FIG. It shows a front view. FIG.
(B) is a cross-sectional view taken along line XX of (a) . In each case, the aggregate type structure is simply illustrated. The inner wall of the accommodating portion of the conductive electrode container 1 is provided with fold-like irregularities 1b. In this way, simple bottomed
The surface area of the storage section is larger than that of the cylindrical shape. In the same manner as in Example 1, the electrode container was filled with the granular electron-emitting substance raw material powder without pressurizing, and then embedded in carbon powder and fired while flowing nitrogen to produce a discharge lamp electrode. The conductive electrode container 1 used at this time has a substantially cylindrical shape with a bottom and a side surface of the bottomed cylinder.
In this case, a material obtained by press-molding with a metal mold so as to have fold-like irregularities 1b, or a method in which the raw material powder is molded into a block shape by a metal mold and then ground and fired is used. The shape of the conductive electrode container 1 is as follows. Outer diameter 2.3 mm Overall length 2.0 mm Maximum inner diameter of accommodation section 1.6 mm Minimum inner diameter of accommodation section 1.2 mm Depth of accommodation section 1.5 mm (Example 3) FIG. 5A shows a front view of a discharge lamp electrode. I have. FIG.
(B) is a cross-sectional view taken along line XX of (a) . In each case, the aggregate type structure is simply illustrated. The conductive electrode container 1 includes a projection 1a protruding from the bottom of the housing portion, and the inner wall of the housing portion has crease-like irregularities 1b. By doing so, a simple bottomed cylinder
The surface area of the housing is larger than the shape. Example 1
In the same manner as in Examples 2 and 3, after the granular powder of the electron-emitting substance was filled in the electrode container without applying pressure, the powder was embedded in carbon powder and fired while flowing nitrogen to produce a discharge lamp electrode. The conductive electrode container 1 used at this time has a substantially cylindrical shape with a bottom and the bottom of the bottomed cylinder.
Pressing and molding with a mold so that the protrusion 1a protruding from the portion and the side surface of the bottomed cylinder are provided with a crease-like unevenness 1b, grinding the raw material powder in a block shape after molding with a mold, or substantially A cylindrical shape with a bottom.
A hole was made in the bottom of the processed b and the support portion 1a was inserted and fired. The shape of the conductive electrode container 1 is as follows. Outer diameter 2.3mm Overall length 2.0mm Housing part depth 1.5mm Projection outer diameter 0.5mm Projection whole length 1.2mm Housing part maximum inner diameter 1.6mm Housing part minimum inner diameter 1.2mm (Comparative example) FIG. a) shows a front view of the discharge lamp electrode. FIG.
(B) is a cross-sectional view taken along line XX of (a) . A simple process in which the housing portion of the conductive electrode container 1 is not processed
A pure cylinder with a bottom was used. After filling the electrode container with granular electron-emitting substance raw material powder without pressurizing it in the same manner as in Examples 1 to 3, burying this in carbon powder and firing it while flowing nitrogen to produce a discharge lamp electrode did.
The conductive electrode container 1 used at this time is formed by pressing the electron-emitting material raw material powder obtained above into a cylindrical shape having a bottom with a mold,
The raw material powder was formed into a block by using a mold, then ground and fired. The shape of the conductive electrode container 1 is as follows. Outer diameter 2.3mm Overall length 2.0mm Housing part inner diameter 1.5mm Housing part depth 1.5mm (Evaluation method) Next, a fluorescent lamp was prepared using the discharge lamp electrode obtained by the above method, and its continuous lighting test was performed. Was done. Here, an evaluation method in the continuous lighting test of the fluorescent lamp will be described. When a fluorescent lamp is used as a light source of a backlight for a liquid crystal display, it is desirable that the tube wall temperature of the lamp be 100 ° C. or less in both the direct type and the edge light type. 100 ℃
When the value exceeds, the components of the backlight, such as the reflection plate, the diffusion plate, and the light guide plate, are severely deteriorated and are not practical. However, the tube wall temperature of the fluorescent lamp increases as the lighting time elapses. This is because as the lighting time becomes longer, the amount of the electron-emitting substance 2 in the discharge lamp electrode decreases and the lamp voltage increases, so that the lamp power increases. This state is schematically shown in FIG. As shown in FIG. 7, a time t1 at which the tube wall temperature reaches 100 ° C. was measured as a standard of the lamp life, and was evaluated in a continuous life test. The temperature of the lamp tube wall was measured by the following method. First, the temperature distribution on the bulb was measured by an infrared thermography thermometer. As a result, the position on the bulb near the end of the lamp tube had the highest temperature.
Therefore, in a space kept at a constant temperature of 25 ° C., the paste-type K thermocouple was directly attached to the position on the bulb near the end of the lamp tube, that is, the thermocouple paste portion 11 (see FIG. 1), and the tube wall temperature was measured. . In addition, aggregate-type structured packing 2
Was determined by embedding and polishing a discharge lamp electrode after discharge in a resin, taking a cross-sectional state, taking an electron micrograph, and analyzing the image. The lamp shape and the conditions of the continuous lighting test are as follows in all of Examples 1 to 3 and Comparative Examples. Lamp length: 100 mm Lamp outer diameter: 4 mmφ Lamp current: 30 mA Driving power supply frequency: 30 kHz The evaluation results are shown in Table 1. The continuous lighting life time t1 and the 10% drop-off time of the aggregate-type structure filler in Examples 1 to 3 and Comparative Example. It is summarized.

[Table 1] The life time t1 of the comparative example was 3000 hr, whereas the life time t1 of Examples 1 to 3 achieved 6000 hr or more (twice or more times the comparative example). FIG. 8 shows the relationship between the amount of the aggregate-type structure filler 2 dropped by the discharge and the continuous lighting time. As shown in FIG.
In the comparative example, 40% of the filler had already fallen off at the same 3000 hr while the shedding could be suppressed to 10% or less. Also, when compared with the amount of falling off of 10% or less, the comparative example was only 1000 hr. The falling off of the aggregate-type structure filling 2 causes a shortage of the electron-emitting substance, and causes an increase in the lamp voltage, that is, an increase in the tube wall temperature. However, in the discharge lamp electrodes of Examples 1 to 3, since the surface area of the conductive electrode container 1 supporting the aggregate-type structure filler 2 is larger than that of the comparative example, the amount of the aggregate-type structure filler 2 falling off is compared. Much less than the example. For this reason,
Even when the lighting time is long, the shortage of the electron-emitting substance hardly occurs, and the temperature rise of the tube wall is suppressed.
The life times t1 of ~ 3 are longer than the life time t1 of the comparative example. From the above, in Examples 1 to 3, the effect of increasing the surface area of the conductive electrode container 1 that supports the aggregate-type structure filling 2 and thereby extending the life time t1 was obtained.

As described above, by using the electrode of the present invention as a discharge lamp electrode for a fluorescent lamp or the like, it is possible to prevent the aggregate-type structure filling from falling off during discharge, thereby reducing the temperature of the lamp tube wall. It is possible to suppress the rise and maintain stable arc discharge for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a fluorescent lamp according to the present invention (a) tube end and (b) an enlarged view.

FIG. 2 is a process chart showing a discharge lamp electrode material and a method of manufacturing a discharge lamp electrode of the present invention.

FIG. 3A is a front view of the first embodiment of the present invention, and FIG.
Sectional view along line XX of (a)

FIG. 4A is a front view of a second embodiment of the present invention, and FIG.
Sectional view along line XX of (a)

5A is a front view of Example 3 of the present invention, and FIG. 5B is a cross-sectional view taken along line XX of FIG.

6 (a) is a front view of a conventional example , and FIG. 6 (b ) is XX of FIG.
Cross section at line

FIG. 7 is a diagram showing a relationship between a continuous lighting time and a lamp tube wall temperature in a fluorescent lamp.

FIG. 8 is a diagram showing the relationship between the continuous lighting time and the amount of the aggregate-type structure filler falling off in Examples 1 to 3 of the present invention and Comparative Example.

FIG. 9 is a schematic view showing an aggregate type structure.

[Explanation of symbols]

 1: Conductive electrode container 1a: Protrusion 1b: Ridged unevenness 2: Aggregate type structure filling 3: Mercury dispenser material 4: Metal pipe 5: Lead wire 6: Enlarged section 7: Conductive pipe 8: Opening 9 ： Valve 10 ： Discharge space 11 ： Attached thermocouple

────────────────────────────────────────────────── (5) References JP-A-7-296768 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 61/067 H01J 61/06

Claims (6)

(57) [Claims] 1. A first component comprising a compound containing at least one of Ba, Sr and Ca, a second component consisting of a compound containing Zr and / or Ti, and a compound containing Ta and / or Nb. An aggregate-type structure filler made of an electron-emitting substance containing a third component is provided, wherein the filler is contained in an electrode container, and the electrode container has a bottomed cylindrical shape, and is contained in the container. Comprises a housing for accommodating said packing , said housing comprising a support for supporting the aggregate-type structured packing.
A supporting portion , wherein the supporting portion is an inner bottom surface and / or an inner surface of the bottomed cylinder.
A discharge lamp electrode , wherein the surface area of the housing part is larger than the surface area of the inner wall of the simple bottomed cylinder. 2. The method according to claim 1, wherein the electrode container is a conductive high melting point metal,
2. The discharge lamp electrode according to claim 1, wherein the electrode is made of ceramics having conductivity on the surface or entirely by firing in a reducing atmosphere. 3. 3. The storage unit and / or the support unit,
Including a first component composed of a compound containing at least one of a, Sr, and Ca, a second component composed of a compound containing Zr and / or Ti, and a third component composed of a compound containing Ta and / or Nb The discharge lamp electrode according to claim 1 , wherein the discharge lamp electrode is made of a material. 4. The electron-emitting substance according to claim 1, wherein the first component is X,
When the second component is Y and the third component is Z, the molar ratio is in a range represented by 0.8 ≦ X / (Y + Z) ≦ 2.0, and the second component is 0.05. Mol ≦ Y ≦ 0.6
The discharge lamp electrode according to any one of claims 1 to 3 , wherein the moles and the third component satisfy 0.4 mol ≤ Z ≤ 0.95 mol. 5. The method according to claim 5, wherein the surface of the electron-emitting substance is made of Ta or N.
The discharge lamp electrode according to any one of claims 1 to 4 , wherein a carbide and / or nitride sputtering prevention layer (b) is formed. 6. A first component comprising a compound containing at least one of Ba, Sr and Ca, a second component consisting of a compound containing Zr and / or Ti, and a compound containing Ta and / or Nb. An aggregate-type structured packing made of an electron-emitting material containing a third component is provided, and the packing is housed in an electrode container.The electrode container has a bottomed cylindrical shape, and the packing is filled in the container. Equipped with a storage section for storing
And the storage section supports aggregate-type structured packing.
And a supporting portion, wherein the supporting portion is the bottomed circle.
Projected from the inner bottom surface and / or inner side surface of the cylinder into the housing
A method for manufacturing a discharge lamp electrode , wherein the surface area of the housing is larger than the surface area of the inner wall of a simple bottomed cylinder, wherein the filler is the first component, the second component, After mixing and calcining the raw material composed of the third component and crushing, granulation is performed to obtain a granular powder, and the granular powder is filled in an electrode container provided with a support portion,
An aggregate-type structured packing is obtained by firing in a reducing atmosphere.
6. The method for producing a discharge lamp electrode according to any one of items 5 to 5 .