JPH0512918Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Purpose of the invention] (Field of industrial application) The present invention relates to an electrode for a discharge lamp using semiconductor porcelain. (Prior art) Taking a discharge lamp using a cold cathode such as a sodium lamp as an example, the discharge electrode constituting the cathode has an electron emitting substance (barium, strontium, It is formed by applying a calcium-based oxide). However, the above-mentioned conventional electrodes cannot avoid the evaporation of the electron-emitting substance and the reaction with the mercury vapor sealed inside the discharge lamp, and therefore do not fully satisfy the various characteristics required of the discharge lamp. Tungsten is a strategic material and has the problem of high cost. Incidentally, a discharge lamp with electrodes made of semiconductor porcelain whose main component is crystalline titanium oxide is known (Special Publication No. 3596/1983), but lamps using such materials have poor discharge characteristics and are difficult to put into practical use. This is not preferable because it has the problem of . (Problems to be solved by the invention) Therefore, the main purpose of the invention is to create a discharge lamp that is inexpensive, has excellent characteristics in terms of discharge characteristics, etc., is suitable as a cold cathode, and can also be used as a hot cathode. The purpose is to provide electrodes. [Structure of the invention] (Means for solving the problems) The electrode for a discharge lamp of the invention includes a tube body for a discharge lamp,
A cathode electrode part formed of semiconductor porcelain mainly composed of BaTiO ₃ , SrTiO ₃ , BaZrO ₃ , or SrZrO ₃ and having a cylindrical shape and having a circular discharge surface on its end surface;
The device is characterized in that it has a sealing support portion that seals and supports the cathode electrode portion within the tube body. (Function) According to the electrode with the above configuration, BaTiO ₃ , SrTiO ₃ ,
Since it uses semiconductor porcelain whose main component is either BaZrO ₃ or SrZrO ₃ , it has excellent discharge characteristics and can be applied to both hot cathodes and cold cathodes, and has a circular discharge surface that allows for stable discharge and concentrated discharge. This has the advantage that blackening can be further prevented. (Embodiment of the invention) A first embodiment of the invention will be described below in detail with reference to FIG. The electrode for a discharge lamp shown in the figure is a tube body 1 for a discharge lamp.
and a cathode electrode section 2 made of semiconductor porcelain disposed inside the tube body 1, and the cathode electrode section 2 is sealed and supported inside the tube body 1 and near the end 1a of the tube body 1. The sealing support part 3 is configured. As shown in FIG. 2, the cathode electrode portion 2 is made of semiconductor ceramic and includes a base portion 2b with one end surface serving as a circular discharge surface 2a. If such a circular discharge surface is used, stable discharge characteristics can be obtained because it becomes a surface discharge, and since the surface diameter is small compared to the length of the cathode electrode, a concentrated discharge can be performed, which makes it possible to use a discharge lamp. When applied to , it exhibits even greater blackening prevention effects. The sealing support section 3 has a lead wire 4 that is arranged to penetrate through the end 1a of the tube body 1 and is sealed and supported at this end portion 1a, and the lead wire 4 is provided inside the tube body. By winding the end portion 4a around the outer periphery of the base portion 2b, the cathode electrode portion 2 is supported within the tube body 1 so that its circular discharge surface 2a is arranged parallel to the end portion 1a, and the end portion of the tube body 1 is The other end 4b of the lead wire 4 is made to protrude outward from the portion 1a. Next, a second embodiment of the present invention will be described with reference to FIG. In the discharge lamp electrodes shown in the figure, those having the same functions as those shown in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted. The electrode for a discharge lamp shown in the figure is different from the electrode shown in FIG.
The projecting end 2c is made to project outward from the end 1a by penetrating the central part of the base 2b, and the penetrating portion of the base 2b is sealed to the end 1a. The sealing support part 13 is formed by screwing together the screw body 15 embedded in the upper end 14a of the lead wire 14. The cathode electrode portion 2 is energized by connecting the lead wire 14 to a power source (not shown). The connection between the lead wire 14 and the cathode electrode section 2 is achieved by fitting a cylindrical cap 16 to which the upper end 14a of the lead wire 14 is fixed onto the protruding end 2c as shown in FIG. You can do it like this. Here, the semiconductor porcelain that is the material of the cathode electrode section 2 will be described in detail. As this semiconductor ceramic, for example, valence compensation type semiconductor ceramic can be mentioned. A typical example of the valence-compensated semiconductor ceramic is one using barium titanate. In addition, as is well known, valence compensation is the addition of metal ions as impurities whose valence differs by ±1 from the constituent metal ions of a metal oxide, and the increase or decrease in the amount of charge caused by the introduction of impurities. This is compensated by the valence of the metal ion. The semiconductor agent for valence compensation includes Y,
Dy, Hf, Ce, Pr, Nd, Sm, Gd, Ho, Er,
Examples include Tb, Sb, Nb, W, Yb, Sc, Ta, etc., and they can also be added in combination. The amount of this additive added is 0.01 to 0.8 mol.
%, especially 0.1 to 0.5 mol%. On the other hand, the material constituting the cathode electrode part 2 made of semiconductor ceramic in this embodiment is preferably a titanate-based material, and in addition to the above-mentioned barium titanate, strontium titanate-based, calcium titanate-based, and lanthanum titanate-based materials are used. It may be. A combination of them may also be used. Furthermore, the titanic acid in the titanate may be replaced with one or more of zirconic acid, silicic acid, and stannic acid. By the way, in addition to the method of reducing semiconductor ceramic for cathode electrodes as described above, it can also be obtained by a method of reducing without adding a semiconductor agent if sufficient reducing conditions are provided. The reduction in this case can be carried out in a reducing atmosphere such as N ₂ or H ₂ and at a temperature of preferably 700°C or higher, most preferably about 1200 to 1450°C. Further, an electrode can also be formed using a combination of a valence compensation type and a forced reduction type. Examples of this combination include: (a) A semiconductor forming agent is added to produce a valence-compensated semiconductor ceramic molded body. (b) Semiconductor porcelain using both valence compensation type and forced reduction type is obtained by directly reducing and firing the molded body of (a) or by further reducing and firing the air-fired sintered porcelain. The tip of this semiconductor porcelain was ground into a conical shape of approximately 60°. The specific resistance of the semiconductor porcelain thus obtained is 9.9Ω
It was cm. Furthermore, H ₂ concentration 20% in a reducing atmosphere of H ₂ + N ₂
The specific resistance was 0.90 Ωcm after reduction firing at 1250°C for a stabilization time of 2 hours. Almost similar results were obtained for other titanate systems. Table 1 summarizes the results.

[Table] Furthermore, almost similar results were obtained for titanates in which titanic acid was replaced with one or more of zirconic acid, silicic acid, and stannic acid. Next, in order to examine the ease with which electrons are emitted, field emission intensity was measured for the above samples No. 1 to No. 3. Also, for comparison, Al, which has a relatively low work function,
Other measurements were also made. The results are shown in FIG. In this figure, the vertical axis shows the discharge generation voltage [KV] in the polyethylene container, and the horizontal axis shows the sample electrodes.Cu, Al, and Fe are used as comparative examples for the sample electrodes, and the samples in Table 1 above are used as sample electrodes. No. 1 to No. 3 are lined up. As is clear from the figure, the samples of this example are more likely to cause discharge even when the generated voltage is lower than that of the conventional samples. According to the above results, it can be seen that this semiconductor porcelain has discharge characteristics equivalent to or better than metals for use in the cathode electrode according to this example. Therefore, it can be applied to both cold cathodes and hot cathodes. Therefore, the cathode electrode section 2 formed using this semiconductor ceramic can obtain stable discharge characteristics in combination with the circular discharge surface, and can also reduce manufacturing costs. Further, by using a connection structure of the lead wire 14 to the cathode electrode portion 2 as shown in FIG. 3 or 4, the connection process can be facilitated. The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention. [Effects of the invention] As described above, the invention provides an electrode for a discharge lamp that can be constructed at low cost, has good discharge characteristics, is suitable for a cold cathode, and is also applicable to a hot cathode. be able to. Furthermore, since the discharge surface is circular, stable discharge and concentrated discharge are possible, and blackening can be further prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention;
FIG. 2 is a perspective view of the cathode electrode section same as above, FIG. 3 is a sectional view showing a second embodiment of the present invention, and FIG.
FIG. 5 is a cross-sectional view showing a modified example of the sealing support part in Example 1, and FIG. 5 is a correlation diagram showing the field emission intensity measurement results in this Example. DESCRIPTION OF SYMBOLS 1... tube body, 2... cathode electrode part, 2a... circular discharge surface, 2b... base, 3... sealing support part, 4...
…Lead.

Claims (1)

[Scope of claims for utility model registration] (1) Tube body for discharge lamp, BaTiO ₃ , SrTiO ₃ ,
A cylindrical cathode electrode part made of semiconductor porcelain whose main component is either BaZrO ₃ or SrZrO ₃ and having a circular discharge surface on its end face, and a sealing support that seals and supports this cathode electrode part in the tube body. An electrode for a discharge lamp, comprising: (2) The sealing support part passes through the end of the tube, and the end of the lead wire sealed at this end on the inside of the tube is separated from the circular discharge surface of the cathode electrode part. The electrode for a discharge lamp according to claim 1, which is constructed by winding the electrode on the opposite side. (3) The sealing support portion is constructed by sealing the portion of the cathode electrode portion opposite to the circular discharge surface with the end of the tubular body.Claim 1 of the Utility Model Registration Claim. Electrodes for discharge lamps as described. (4) The sealing support part has a lead wire connected to an end of the cathode electrode part protruding outward from the tube body, and the sealing support part has a lead wire connected to an end of the cathode electrode part projecting outward from the tube body. Electrodes for electric lights.