JPS59165362A - High pressure discharge lamp - Google Patents

Abstract

PURPOSE:To prevent flickering of luminescence in restarting by specifying a relation of the diameter of a metal wire constructing a filament and the minimum diameter of a metal wire constituting a main electrode. CONSTITUTION:A filament 14 is arranged near a main electrode 2a and consists of a metal wire electrically connecting to the main electrode 14. A high pressure discharge lamp has a luminescent tube 1 which has the filament 14 and in which mercury is sealed, and current is made flow through the filament 14 when starting. When a diameter of a metal wire of the filament is indicated by dmm. and a diameter of a metal wire having the minimum diameter is indicated by Dmm., a relation of d and D is specified so as to become D<3d. For example, the filament 14 is a coil having an inner diameter of 0.4phi, comprising a 0.08phi tungsten wire containing therium oxide. The main electrode 2a is made in such a way that a 0.65phi tungsten rod is used as a core wire 30, and a 0.1phi tungsten wire is wound on to a 0.3phi tungsten wire as the secondary coil 31, and it is wound on to the core wire 30 as the primary coil 32, and a cathode material such as barium oxide is filled in gaps.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to high pressure discharge lamps, and more particularly to improving the restart characteristics thereof.

Traditionally, high-pressure discharge lamps have been used on roads, sports grounds, gymnasiums, and factories, but because high-pressure discharge lamps are compact and highly efficient, they have attracted attention as energy-saving light sources, and are gradually being used in commercial facilities. Its use has become widespread. However, high-pressure discharge lamps have the disadvantage of a long restart time.

In other words, in high-pressure discharge lamps, the mercury pressure inside the arc tube reaches several atmospheres while the lamp is on, so if the lamp goes out due to a temporary drop in the power supply voltage, the lamp will not start immediately even if the power supply voltage returns to normal. However, it was not possible to light the bulb until the temperature of the arc tube dropped and the pressure of mercury vapor inside the bulb dropped to a state where discharge could begin. The time from when the lamp goes out until it can start discharging again is called the restart time, and high-pressure mercury lamps require 3 to 5 minutes.

Therefore, in order to shorten this restart time, a method is proposed in which a heating element is installed near the main electrode, and upon restarting, this heating element is heated to release electrons into the discharge space, and a voltage is applied between the main electrodes. known to be effective. By rolling it up, we made a lamp with a filament installed as a heating element and conducted a long-time lighting test.

However, when the lighting time exceeds 4,000 hours, some lamps generate a discharge between the filament and the main electrode that is not close to the filament when restarted, and then the discharge does not transfer from the filament to the main electrode that is close to the filament. , a phenomenon was observed in which the filament began to function as the main electrode. In such a case, the amount of electrons supplied to the discharge arc is not equal between the filament and the main electrode, so the light emission appears to flicker, giving an unpleasant feeling.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a high-pressure discharge lamp that does not flicker when restarting, and is made in view of the drawbacks of conventional high-pressure discharge lamps.

Hereinafter, the high pressure discharge lamp of the present invention will be described in more detail with reference to preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a high pressure discharge lamp in an embodiment of the present invention,
FIG. 2 shows the main electrode in the high pressure discharge lamp.

In FIG.
Main electrodes 2a and 2b are provided at both ends of the main electrode. A filament 14 made of a tungsten wire is provided near the main electrode 2a, and one end of the filament 14 is connected to a molybdenum foil 4a connected to the main electrode 2a, thereby being electrically connected to the main electrode 2a.

The main electrode 2a includes a molybdenum foil 4a, a lead 5a, a stem lead 7a, a lead 15a, and a choke coil type ballast 16.
, are connected to one terminal of the cap 8 via a lead 17. On the other hand, the main electrode 2b is a molybdenum foil 4b1 lead 5b.
, the support frame 9, the stem lead 7b, and the lead 18.
It is connected to the other terminal of the base 8. The other end of the filament is a molybdenum foil 19, leads 20a, 20
b It is connected to one terminal of a lighting tube 22 which is a starting voltage generating means through the stem lead 21, and the other terminal of the lighting tube 22 is further connected to the stem lead 7b, and eventually the main electrode 2b It is connected to the.

The lighting tube 22 has a normally open bimetal switch installed in a glass tube filled with an appropriate amount of rare gas, and the bimetal switch closes due to the heat of no glow discharge between the bimetals, and then cuts off the current when it cools and opens. This is a normal glow starter type that induces a surge in the ballast 16, which is an inductive element. Reference numeral 25 denotes a starting aid made of a molybdenum wire with a diameter of 0.1φ, which is tightly wound around the outer wall of the arc tube 1 and fixed to the support frame 9. In addition, 6 is a stem, and three stem leads 7a, 7b, and 21 are sealed, and this stem 6 is sealed in the outer tube 13, and the inside is kept in an inert gas atmosphere. . Further, reference numeral 23 denotes a ballast case made of stainless steel with a cylindrical side surface, with a ballast 16 fixed inside one end surface, and a base 8 protruding outward from the end surface.
is fixed.

The other opening surface is integrally bonded to the stem 6.

Further, the inner surface of the outer tube 13 is coated with a phosphor. 2
Reference numeral 4 denotes a reflector plate, which is provided so as to effectively radiate light or ultraviolet light forward and to shield the ballast 16 and lighting tube 22 from infrared light.

In addition, in this example, the inner diameter of the arc tube 1 is 0.6φ, and the main electrode 2a
, the distance between 2b is 1.6, the internal volume is 0.570C, the amount of mercury sealed is 2.3 mg, and argon is sealed at 25 torr.

This high pressure discharge lamp operates as follows. (Regarding starting [7, When the power supply is connected directly to the cap 8, the lighting tube 2
2 starts glow discharge, lighting tube 22, filament 14
Current flows through the paddle 5 ballast 16. After the bimetallic switch of the lighting tube 22 closes and the filament 14 is heated, the bimetallic switch opens and cuts off the current, generating a surge voltage that is the starting peak voltage, and the amphibious electrode 2a
, 2b is applied, discharge begins, and starting is completed. Regarding (I[) lighting, as in the conventional example,
All of the mercury evaporates, and the luminescence of mercury is used for lighting. (■λ Regarding restarting, when the power is connected immediately after the light goes out, a current flows through the lighting tube 22, the filament 14, and the ballast 16 in the same way as when starting, the filament 14 is preheated and becomes red hot, and the main electrode 2a , 2b, and further, the starting auxiliary body 25 partially strengthens the electric field, so that the discharge starting voltage is lowered to 11.1.5 KV or less.Then, the lighting tube 22 starts operating. Yes, 1.5~
A surge voltage of about 2 KV is generated to start preheating, and discharge begins between the bipolar electrodes 2a and 2b.

The filament 14 is made of a 0.08φ tungsten wire containing 1% thorium oxide wound into a coil with an inner diameter of 0.4φ, and after deformation, a 0.4φ molybdenum wire is fully inserted into both ends and welded. As shown in FIG. 2, the main electrode 2a has a 0.65φ tungsten rod as the center @aO, and
．． 0.3 using 1φ tungsten wire as the secondary coil 31
It is wound around a tungsten wire having a diameter of φ, and this is used as the primary coil 32 and wound around the core wire 3o. These gaps are filled with a cathode material mainly consisting of barium oxide.

By the way, in the conventional lamp, after being lit for a long time as described above, the discharge does not move from the filament to the adjacent main electrode when restarting, and the reason for this is estimated as follows.

(1) At the beginning of lighting, there was sufficient cathode material on the main electrode, so discharge easily moved to the main electrode.

(2) After lighting for a long time, the amount of cathode material on the main electrode decreases, so the cathode material does not cover the main electrode surface sufficiently, and the material transfers.
＜, it became.

(3) At the time of startup when the mercury pressure was sufficiently reduced, the density of the gas inside the arc tube was low, so the discharge spread and easily transferred to the main electrode.

Therefore, we created a lamp using a main electrode that was not coated with cathode material, which is considered to be the worst condition, but even before the lamp lighting test, discharge did not transfer to the main electrode. Then, we investigated the conditions under which the discharge would move to the main electrode under these worst conditions. In particular, the wire diameter dmm of the filament and the wire diameter Dm of the secondary coil 31, which is the thinnest wire of the main electrode 2a.
Focusing on m, as a result of prototyping various combinations, D(3
It has been found that if the relationship d is satisfied, a discharge can be transferred between the main electrodes even if there is no cathode material at all in the main electrodes.

Furthermore, for confirmation, lighting tests were conducted on many of the lamps of the above-mentioned embodiments, but no phenomenon was observed where discharge did not transfer from the filament 14 to the adjacent main electrode.

In this way, the wire diameter of a part of the main electrode 2a is changed to the diameter of the filament 1.
The reason why the discharge transfers favorably from the filament 14 to the main electrode when the ratio is below a certain level with respect to the wire diameter is considered to be that the smaller the wire diameter, the smaller the heat capacity, and the faster the temperature rise. Furthermore, although the reason why D<d is not achieved has not been precisely elucidated, it seems to be related to the fact that the main electrode is located at the center of the arc tube, where it is more likely to become a discharge path.

It is clear that as long as D (3d) is satisfied, it does not depend on the structure of the main electrode.Furthermore, the same effect can be obtained even if the filament is a tungsten wire that does not contain thorium oxide.

Similar effects can also be obtained with lamps of other dimensions, other types of high-pressure discharge lamps such as metal halide lamps, lamps with different types of rare gases sealed in the arc tubes, etc.

Furthermore, the device that generates high voltage for restarting and the device that passes current through the filament during restarting is also a lighting tube in this example, but it generates a voltage above a certain value, including immediately after lighting,
It can be applied to any device that starts energizing the filament within a short time (within about 5 seconds) after energizing the lamp.

As explained above, the present invention provides a high-pressure discharge lamp that is installed at the end of the filament (1) arc tube for restarting, in which the wire diameter of the filament is d mm, and the portion with the smallest wire diameter constituting the main electrode. If the wire diameter is Dmm, by satisfying the relationship D(3d), the discharge can easily shift to between the main electrodes even after long periods of lighting, and there is no flickering that can be seen when the filament becomes a part of the electrode. A high pressure discharge lamp can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a high pressure discharge lamp according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a main electrode of the high pressure discharge lamp. 1... Arc tube, 2a, 2b... Main electrode, 14...
Filament, 30...Main electrode core wire, 31...2
Next coil, 32...primary coil. Note that the same reference numerals in the figures indicate the same or similar parts. Agent Makoto Kuzuno - Procedural amendment (voluntary) 1. Indication of the case: Japanese Patent Application No. 58-39565 2, name of the invention: high-pressure discharge lamp 3, representative of the person making the amendment: Hitoshi Katayama Department 4, agent 5: column 6 for detailed explanation of the invention of Mei 11i1111F, the subject of the amendment , Contents of the amendment The description of the specification of this application will be corrected as follows.

Claims (1)

[Claims] It has a light emitting tube that includes a pair of main electrodes and a filament made of a metal wire that is placed close to one of the main electrodes and electrically connected to the main electrode, and that has mercury sealed inside. In the high pressure discharge lamp in which the filament is energized, the wire diameter of the metal wire constituting the filament is dmm, and the wire diameter of the metal wire having the smallest diameter among the metal wires constituting the main electrode is Dmm. A high-pressure discharge lamp characterized in that the relationship between d and D is D (3d) when