JPH0517654B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to short arc discharge lamps, such as xenon short arc discharge lamps.

Generally, xenon short arc discharge lamps are
As shown in the figure, lead rods 21 extending into the internal space of the silica glass enclosure 1 are attached to both end sealing portions of the enclosure 1 made of quartz glass.
22 is hermetically sealed, and an anode 3 and a cathode 4 are provided at the tips of the lead rods 21 and 22, respectively, so as to face each other. And envelope 1
consists of a spherical part 11 that surrounds the discharge space where the anode 3 and the cathode 4 are located, and cylindrical parts 12 and 13 that extend horizontally from both sides of the spherical part 11 and surround and hold the lead rods 21 and 22. It is configured. That is, small diameter portions 14 and 15 are formed in portions of the cylindrical portions 12 and 13 that are close to the anode 3 or the cathode 4, so that the lead rods 21 and 22
Displacement of the anode 3 or cathode 4 due to deformation is prevented. In addition, in the figure, 51,5
Reference numeral 2 denotes a cap attached to the sealing portion of the enclosure 1.

By the way, in a large-capacity short arc discharge lamp with a rated power consumption of 2KW or more, for example, the temperature of the anode 3 reaches a high temperature of 2000°C or more, so the material of the anode 3 evaporates and this evaporates into the envelope 1. A so-called blackening phenomenon that adheres to the inner wall of the container begins to occur. When such a darkening phenomenon occurs,
Since the blackened portion of the envelope 1 has a considerably higher light absorption rate than the non-blackened portion, the light output efficiency of the short arc discharge lamp is significantly reduced, and furthermore, the temperature of the blackened portion is higher than that of the non-blackened portion. Distortion occurs in this portion, causing problems such as damage to the envelope 1. Therefore, as the anode 3, it is necessary to use a relatively large one that is made of a metal that has a low vapor pressure at high temperatures and has a large heat capacity in order to suppress the temperature rise of the anode 3. Conventionally, for example, a second As shown in the figure, one made entirely of tungsten is used. In addition, 31 in the figure is a lead rod insertion hole for inserting and connecting the lead rod 21.

However, in a short arc discharge lamp having such an anode 3, the anode 3 is large and the specific gravity of the tungsten constituting it is low.
19.24, which increases the weight of the anode 3, resulting in a problem that sufficient vibration resistance cannot be obtained. That is, when some kind of mechanical shock is applied to the short arc discharge lamp, since the weight of the anode 3 is large, a large bending force is applied to the lead rod 21 that supports the anode 3, so that the lead rod 21 bends and surrounds it. If it hits the small diameter portion 14 of the enclosure 1, the enclosure 1 may crack or burst, resulting in insufficient vibration resistance. In particular, it is strongly desired to solve these problems in short arc discharge lamps used in fishing boats, which are susceptible to large vibrations.

The present invention was made against the above background, and an object of the present invention is to provide a short arc discharge lamp having a lightweight anode and excellent vibration resistance.
Its features include: a glass enclosure having a spherical part surrounding the discharge space and a cylindrical part extending from the spherical part; a lead rod held by the cylindrical part of the enclosure; In a short arc discharge lamp comprising an anode and a cathode, each provided at the tip of the lead rod so as to face each other within the spherical part of the envelope, the anode is in a region where the temperature during operation exceeds 2000°C. A portion of the anode including at least a tip end surface portion and an outer circumferential surface portion following the tip end portion is made of tungsten, and the other portions are made of molybdenum.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The short arc discharge lamp of this embodiment is provided with an anode 3 as shown in FIG. That is, this anode 3 has a low temperature region L that occupies the central portion of the base end and the tip end to which the lead rod 21 is connected.
is made of molybdenum, and the high-temperature region H, which is the outer surface portion of the tip, that is, the tip surface portion of the anode 3 and the outer peripheral surface portion following this tip surface portion, is made of tungsten.

Here, the low temperature range L of the anode 3 refers to the range where the temperature does not exceed 2000°C when the short arc discharge lamp is in operation, that is, when the discharge lamp is lit in a steady state, and the high temperature range H is the range above 2000°C. Refers to an area. If only the surface layer of the high temperature region H is made of tungsten, the parts other than the surface layer of the high temperature region H will be made of molybdenum, and the molybdenum belonging to this high temperature region H is Since the tungsten diffuses relatively easily and eventually evaporates into the internal space of the enclosure 1, in the present invention, it is necessary that at least a portion including the entire high temperature region H be made of tungsten. It is.

The other parts of this embodiment are the same as the short arc discharge lamp shown in FIG. 1, so the explanation will be omitted.

According to the above configuration, the low temperature region L of the anode 3
is made of molybdenum, which has a specific gravity (10.28) that is about half that of tungsten (19.24), so the weight of the anode 3 is significantly reduced compared to when only tungsten is used. the result,
Even when an impact force is applied to the short arc discharge lamp for some reason, the lead rod 21 that supports the anode 3, the cylindrical portion 12 of the enclosure 1 that holds this lead rod 21, and especially the small diameter portion 14 of the short arc discharge lamp. Since no excessive impact force is applied to the enclosure 1, the enclosure 1 is not damaged and has excellent vibration resistance.

By the way, when the low-temperature region L occupies 75% of the volume of the electrode 3, if the entire region of the low-temperature region L is made of molybdenum, the area of the electrode 3 will be approximately 35% smaller than if the entire area of the electrode 3 is made of tungsten. % weight reduction.

Furthermore, since tungsten, which has a low vapor pressure, is used in the high temperature region H of the anode 3, and molybdenum, which has a relatively high vapor pressure, is used only in the low temperature region L, the amount of evaporation of the materials that make up the anode 3 as a whole is small. Therefore, blackening of the envelope 1 is less likely to occur, and therefore, a high light output efficiency comparable to that of conventional short arc discharge lamps can be maintained for a long period of time. In other words, the operating temperature of all the parts of the anode 3 made of molybdenum is 2,000°C or less, and the rate at which molybdenum diffuses through tungsten is extremely slow, so the normal service life is 1,000 degrees. If it is a xenon short arc lamp that lasts for about an hour, molybdenum will not diffuse through the tungsten and reach the surface of the high temperature region H within this service life.
Therefore, the occurrence of blackening can be suppressed.

FIG. 4 shows an anode in another embodiment of the invention. In this example, the entire outer circumference H ₀ of the anode 3 including the high temperature region is made of tungsten, and the other parts are made of molybdenum. Evaporation can be more reliably prevented than in the embodiments described above.

The anode of the present invention is easily manufactured by first molding a center portion occupying a low temperature region using molybdenum, and then sintering and molding powdered tungsten around the outer periphery of this molded body.

As described above, the short arc discharge lamp according to the present invention includes a glass envelope having a spherical part surrounding a discharge space and a cylindrical part extending from the spherical part, and is held by the cylindrical part of the envelope. and an anode and a cathode respectively provided at the tips of the lead rod so as to face each other within the spherical part of the enclosure, and the anode has a temperature exceeding 2000°C during operation. Since the region including at least the tip end surface portion of the anode and the outer circumferential surface portion following the tip end portion is made of tungsten, and the other portion is made of molybdenum, it has excellent vibration resistance. have sex,
For example, it is highly practical as a discharge lamp for fishing.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing an example of the configuration of a short arc discharge lamp, FIG. 2 is an explanatory sectional view showing a conventional anode that constitutes a short arc discharge lamp, and FIG. 3 is a configuration of a short arc discharge lamp according to the present invention. FIG. 4 is an explanatory sectional view showing an anode of another embodiment of the short arc discharge lamp according to the present invention. 1... Enclosure, 11... Spherical part, 12, 13...
Cylindrical part, 14, 15... Small diameter part, 21, 22...
Lead rod, 3... Anode, 31... Lead rod insertion hole, L... Low temperature range, H... High temperature range, 4... Cathode,
51, 52...cap.

Claims (1)

[Scope of Claims] 1. A glass enclosure having a spherical part surrounding a discharge space and a cylindrical part extending from the spherical part, and a lead rod held by the cylindrical part of the enclosure;
In a short arc discharge lamp comprising an anode and a cathode, each provided at the tip of the lead rod so as to face each other within the spherical part of the enclosure, the anode may be used in a region where the temperature during operation exceeds 2000°C. A short arc radiation source is characterized in that a portion of the anode including at least a tip end surface portion and an outer circumferential surface portion following the tip end portion is made of tungsten, and the other portion is made of molybdenum. electric light.