JPH0433639Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an improvement in a trigger electrode attached to a shot arc discharge lamp that is lit with direct current, such as a xenon discharge lamp or an ultra-high pressure mercury discharge lamp. [Background of the invention and its problems] Direct current shot arc discharge lamps are widely used as light sources for lighting, but recently they have suddenly become popular as light sources for lighting large-scale high-intensity video projectors and for printing semiconductor integrated circuits. They are in the spotlight and are increasingly being placed in close proximity to complex electronic circuits. When lighting a DC shot arc discharge lamp,
A high-voltage, high-frequency trigger pulse must be applied between the electrodes to cause dielectric breakdown between the electrodes, and a starter device that outputs a high-voltage, high-frequency trigger pulse is required. In particular, xenon shot arc discharge lamps with a gas filling pressure of 15 to 20 atmospheres have a high starting voltage, reaching around 20-odd kilovolts, so the starting device is not only large and expensive, but also generates a trigger pulse. The noise generated when doing so also becomes large. Since this noise can cause peripheral electronic circuits to malfunction, it is necessary to reduce the starting voltage and make the noise as small as possible. As a means to reduce the starting voltage,
For example, as shown in FIG.
This is done by attaching a trigger electrode 3 fixed to the shoulders 12a and 13a of the trigger electrode 3, but the voltage is reduced by about 15% at most.
Further reduction is desired. [Purpose of the invention] Therefore, an object of the present invention is to provide a DC discharge lamp equipped with a trigger electrode of a novel structure that can lower the starting voltage even more than that of conventionally used trigger electrodes. [Structure of the invention] The structure of the invention includes a substantially ellipsoidal light-emitting part in which a cathode and an anode are arranged facing each other, and a cathode conductor and an anode conductor extending outward from the cathode and anode, respectively, following the light-emitting part. A DC discharge lamp comprising a quartz glass enclosure comprising a sealed cathode sealing part and an anode sealing part, and a trigger electrode attached across the light emitting part of the enclosure. The trigger electrode is emitted from one shoulder on the side where the cathode tip is displaced from the plane containing the maximum diameter of the light emitting part, passes through the other shoulder on the diagonal line, and reaches the starting point of the one shoulder. The distance between the trigger electrodes in a plane including the diameter passing through the cathode tip of the light emitting section is smaller than the outer diameter of the diameter, and the trigger electrode and the cathode are electrically connected to each other. It is characterized by being connected. [Effect] With such a configuration, the starting voltage can be significantly lowered, as will be clear from the explanation below. This results in a smaller starting device and
Since the noise generated when the trigger pulse is generated is also small, the semiconductor electronic circuit is less likely to malfunction, and the price of the starting device can be reduced. [Example] Hereinafter, an example of the present invention will be described in detail based on a drawing of a xenon short arc discharge lamp in which the cathode is displaced backward from the plane containing the maximum diameter of the light emitting part. FIG. 1 is an explanatory diagram of one embodiment of the present invention,
The quartz glass enclosure 1 includes a substantially elliptical spherical light emitting section 11 formed at the center, and a cathode sealing section 12 and an anode sealing section 13 extending outward from both ends of the light emitting section 11. It consists of In the light emitting part 11, a cathode 21 and an anode 31 are arranged facing each other, and a molybdenum foil 22, which is a cathode conductor, is connected to the base end 21a of the cathode 21 by welding. A cathode external lead rod 23 is connected by welding. These molybdenum foils 22, a part of the cathode, and a part of the external lead rod are connected to the cathode sealing part 1 of the sealing body 1.
2 is buried and sealed. Similarly, on the anode side, a molybdenum foil 32 which is an anode conductor, a part of the anode 31 and a part of the anode external lead rod 33 are electrically connected by welding, and are embedded in the anode sealing part 13 and sealed. It has been stopped. A trigger electrode 3 is disposed on the outer surface of the envelope 1 of the DC discharge lamp configured in this manner. The trigger electrode 3 is made of, for example, a conducting wire made of Fe-Ni alloy and has a thickness of 0.5 mm, and is connected to the cathode shoulder portion 12.
a, passes through the diagonal anode shoulder 13a, returns to the same cathode shoulder 12a as the starting point, and is connected to the cathode external lead rod 23 that protrudes outward from the cathode sealing part 12. They are electrically connected by a line 34. At this time, the trigger electrodes are arranged as close as possible to each other near the cathode tip, but this distance is smaller than the outer diameter of the light emitting section 11 passing through the cathode tip. Reference numeral 35 denotes a trigger electrode fixing portion provided by wrapping a portion of the trigger electrode 3 around the cathode shoulder portion 12a. FIG. 2 is an explanatory diagram of another embodiment of the present invention, in which a trigger is emitted from the cathode shoulder 12a, passes through the diagonal anode shoulder 13a, and returns to the starting point, the cathode shoulder 12a. Place electrode 3 in symmetrical position 2
This is an example of an assembly. Here, to give an example of specific numerical values in the above configuration, in the case of a xenon shot arc discharge lamp with a rated power consumption of 150W (7.5A, 20V), for example, the total length L ₁ of the envelope 1 is 100 mm, and the light emitting part 11 length
L ₂ is 25 mm, central bulge outside diameter D is 20 mm, cathode 2
The distance 1 between the electrodes 1 and the anode 31 facing each other is
2.5 mm, the length of the trigger electrode attached to the light emitting part 11 is 65 mm, the distance between the two trigger electrodes running on the surface of the light emitting part surrounding the cathode tip is 12 mm, and the sealed pressure of xenon gas is 20 atmospheres. Due to this configuration, xenon shot arc discharge lamps that are lit with direct current have significantly lower starting voltages than DC discharge lamps equipped with conventional trigger electrodes, as is clear from the experimental data described below. It is possible to measure the reduction of Although it is not clear why such a configuration can reduce the starting voltage, the inventors' research has revealed the following. In other words, the present inventors created a 150W rated xenon shot arc discharge lamp (arc length 2.5 mm, xenon filling pressure 20 atm) with trigger electrodes of various structures attached for the purpose of reducing starting voltage.
An experiment was conducted to measure the starting voltage. That is, a DC-lit xenon shot arc discharge lamp is provided with a trigger electrode having the structure shown in FIG. 3 taken up as a conventional example, and a trigger electrode having the structure shown in FIG. 4 added to FIG. 3; Experiments were conducted using a DC-lit xenon shot arc discharge lamp equipped with a trigger electrode according to the present invention shown in FIG. 2, and the results shown in Table 1 were obtained. From Table 1, it can be seen that when the conventionally used trigger electrode shown in Fig. 3 is used and no connection is made to the cathode, the starting voltage is as high as 20kV, but the starting voltage of Figs. 1 and 2 according to the present invention is high. Using a trigger electrode,
The starting voltage when connected to the cathode is 15kv, respectively.
It can be seen that the starting voltage is considerably effective in reducing the starting voltage. The reason why the starting voltage can be reduced in this way can be predicted from the experimental results shown in Table 1, and the following can be found.

[Table] To summarize the results of (1) to (3) above, in order to reduce the starting voltage, the number of trigger electrodes spanning the light emitting part should be two or more, and the trigger electrode and cathode should be connected. The trigger electrodes are electrically connected and disposed close to each other near the cathode tip. The embodiment of the present invention satisfies all of the above conditions and can reduce the starting voltage by 25 to 35% compared to the case where a conventional trigger electrode is used. In addition, when the cathode tip is displaced forward of the plane including the maximum diameter of the light emitting part, as in the case of an ultra-high pressure mercury lamp, the trigger electrode may be arranged so that the light is emitted from the anode shoulder. As can be understood from the above embodiments, according to the present invention, the starting voltage of a shot arc discharge lamp that is lit with direct current can be significantly lowered, so a small and inexpensive starting device is used. In addition, since the noise generated when the trigger pulse is generated can be made small, it is possible to provide a DC discharge lamp in which peripheral electronic circuits are less likely to malfunction.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of one embodiment of the DC discharge lamp of the present invention, Figure 2 is an explanatory diagram of another embodiment of the present invention, and Figure 3 is an explanatory diagram of another embodiment of the present invention.
The figure is an explanatory diagram of a conventional DC discharge lamp, and FIG. 4 is an explanatory diagram of a DC discharge lamp for comparison. DESCRIPTION OF SYMBOLS 1... Sealing body, 3... Trigger electrode, 11... Light emitting part, 12... Cathode sealing part, 13... Anode sealing part, 21... Cathode, 22... Cathode conductor, 23...
... Cathode external lead rod, 31 ... Anode, 32 ... Anode conductor, 33 ... Anode external lead rod, 34 ...
connection line.

Claims (1)

[Claims for Utility Model Registration] A substantially ellipsoidal light-emitting part in which a cathode and an anode are arranged facing each other, and a cathode conductor and an anode conductor extending outward from the cathode and anode, respectively, following the light-emitting part are sealed. In a DC discharge lamp comprising a quartz glass enclosure comprising a cathode sealing part and an anode sealing part, and a trigger electrode attached across the light emitting part of the enclosure, the trigger electrode is , is emitted from one shoulder on the side where the cathode tip is displaced from the plane containing the maximum diameter of the light emitting part, and passes through the other diagonal shoulder,
The trigger electrode is rotated so as to return to the starting point of the one shoulder, and the distance between the trigger electrodes in a plane including the diameter passing through the cathode tip of the light emitting section is smaller than the outer diameter of the diameter, and the trigger electrode A direct current discharge lamp characterized in that the and cathode are electrically connected.