JPH0896755A - High pressure discharge lamp - Google Patents

Abstract

PURPOSE: To extend a life and improve a starting characteristic of a high pressure discharge lamp storing a plurality of luminous tubes in a signal external ball bulb, by providing a specific start assist circuit corresponding to a plurality of the luminous tubes. CONSTITUTION: This high pressure discharge lamp is formed by storing in a single external ball an arc tube 1, formed by mounting a pair of main electrodes (example: 2a, 2b) in both ends of a quartz tube further sealing an auxiliary electrode 3 adjacent to an least the one main electrode 2a to seal at least mercury with start assist gas in the inside, and a plurality of arc tubes 6 (constituted of 7a, 7b, 8) or the like having a similar constitution to this arc tube 1. The auxiliary electrodes (3, 8) of the arc tube and its opposed main electrodes (2b, 7b) are connected through at least one start assist circuit comprising start resistors (4, 9) and bimetal switches (5, 10).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a high pressure discharge lamp having a plurality of arc tubes in one outer bulb.

[0002]

2. Description of the Related Art Recently, two or more arc tubes are housed in one outer bulb, and the color temperature of the lamp is changed by alternately lighting them depending on the season or the time of day, or the irradiation atmosphere is changed. Lamps have been commercialized that extend the lamp life. However, by storing two or more arc tubes, the number of parts inside the outer bulb increases, the outer bulb mounting structure becomes complicated, and not only the workability at the time of manufacturing the lamp is poor, but also the number of parts during the life period is increased. There were problems such as malfunctions and accidental lamp accidents. Further, in order to facilitate the starting of the lamp, a plurality of arc tube starting auxiliary circuits are provided for each arc tube, and even when one arc tube is lit, it is between the auxiliary main poles of other arc tubes. There has been a problem that glow discharge continues to occur and both electrodes are deteriorated.

FIG. 3 shows a circuit diagram of a high pressure discharge lamp which is constructed by accommodating two conventional arc tubes for mercury lamps in one outer bulb. The arc tube 21 has main electrodes 22a and 22b at both ends.
The auxiliary electrode 23 in close proximity to one of the main electrodes 22a.
The auxiliary electrode 23 and the other main electrode 22b are connected via a starting resistor 24. In the same manner as described above, the other arc tube 25 also has main electrodes 26a and 26b sealed at both ends, and an auxiliary electrode 27 is sealed near one main electrode 26a. The electrode 26b is connected via a starting resistor 28. Furthermore, arc tube 2
The main electrodes 22a and 26a of Nos. 1 and 25 are connected to an AC power source 30 via a ballast 29 including a choke coil by a common circuit.
Is connected to one end. Also, the other main electrodes 22b, 2
6b is also connected to the other end of the AC power supply 30 by a common circuit.

When a power supply voltage is applied to the lamp, each arc tube starts discharge between the auxiliary main poles via the starting resistors 24 and 28, but one of the arc tubes having a low starting voltage has a rated lamp voltage. When it reaches the point, the arc discharge occurs between both main electrodes and the lamp is lit. At that time, the lamp voltage is always applied between the auxiliary main electrodes of other arc tubes that are not lit,
The discharge between the auxiliary main poles will be maintained. As a result, there is a drawback that the main electrode and the auxiliary electrode are deteriorated by the glow discharge, and the start-up fails at the time of restarting, although they are not lit.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and extends the life of a high-pressure discharge lamp in which a plurality of arc tubes are arranged in one outer bulb through a starting auxiliary circuit. And to improve the starting characteristics.
INDUSTRIAL APPLICABILITY The present invention improves workability in manufacturing the outer bulb mount by simplifying the outer bulb mount structure, and has a long life in which accidents and the like caused by the complexity of the outer bulb mount structure do not occur during the life of the lamp. An object of the present invention is to provide a high pressure discharge lamp having good starting characteristics.

[0006]

According to the present invention, a pair of main electrodes are provided at both ends of a quartz tube and an auxiliary electrode is sealed in the vicinity of at least one of the main electrodes, and at least mercury is enclosed therein together with a starting auxiliary gas. In a high-pressure discharge lamp in which a plurality of arc tubes are housed in a single outer bulb, at least one starting auxiliary circuit consisting of a starting resistor and a bimetal switch is provided for the auxiliary electrode of the arc tube and the opposing main electrode. It will be connected through. Further, the invention is characterized in that the starting auxiliary circuit of the non-lit arc tube is disconnected by a bimetal switch while the high pressure discharge lamp having the arc tube having a plurality of starting circuits built in the outer bulb is lit. . Furthermore,
In the high-pressure discharge lamp having a plurality of arc tubes in one outer bulb, the starting auxiliary circuit for the arc tubes incorporated in the lamp is one.

[0007]

With the above construction, glow discharge does not occur between the main electrodes of the arc tubes that are not lighted among the plurality of arc tubes, and the deterioration thereof does not occur. Further, the starting auxiliary circuit for a plurality of arc tubes can be made common, so that the starting is easy and reliable, and the number of parts is reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments. FIG. 1 shows a circuit diagram of a high-pressure discharge lamp constructed by housing two arc tubes for mercury lamps in one outer bulb.
The arc tube 1 has main electrodes 2a and 2b sealed at both ends, and an auxiliary electrode 3 sealed near one of the main electrodes 2a. The auxiliary electrode 3 and the other main electrode 2b have a starting resistance 4 And a bimetal switch 5 are connected to each other via a starting auxiliary circuit formed of a series circuit. Similarly, the other arc tube 6 is also formed by sealing the main electrodes 7a and 7b on both ends and sealing the auxiliary electrode 8 close to the one main electrode 7a in the same manner as described above. The electrode 7b is connected via a starting auxiliary circuit including a starting resistor 9 and a bimetal switch 10. Note that the bimetal switches 5 and 10 are thermoresponsive switches that are closed at room temperature and open at a certain temperature or higher. Further, the main electrodes 2a and 7a of the arc tubes 1 and 6 are connected to one end of an AC power supply 12 via a ballast 11 composed of a choke coil by a common circuit. The other main electrodes 2b and 7b are also connected to the other end of the AC power supply 12 by a common circuit.

When a power supply voltage is applied to the lamp, each arc tube starts discharge between the auxiliary main poles via the series circuit of the starting resistor 4 and the bimetal switch 5 or the series circuit of the starting resistor 9 and the bimetal switch 10. However, one of the arc tubes having a low starting voltage, for example, the arc tube 1, is switched to arc discharge and lit. At that time, the bimetal switch 10 connected to the auxiliary electrode 8 of the non-lighted arc tube 6 is opened by the radiant heat of the lighted arc tube 1, and the lamp voltage is applied between the auxiliary main electrodes of the non-lighted arc tube 6. I will not join. It should be noted that the same applies even if the light-emitting arc tube is reversed.

FIG. 2 is a circuit diagram of another embodiment of the present invention. The same parts as those in the above embodiment are designated by the same reference numerals or the reference numerals are omitted. The arc tube 1 has main electrodes 2a and 2b sealed at both ends, and an auxiliary electrode 3 sealed near one main electrode 2a. The auxiliary electrode 3 and the other main electrode 2b have a starting resistance 15
Is connected via a bimetal switch 16.
The other arc tube 6 also has main electrodes 7a and 7b sealed at both ends and an auxiliary electrode 8 sealed near one main electrode 7a. The auxiliary electrode 8 and the other main electrode 7b have a starting resistance. 15 and a bimetal switch 16 which are connected via a common starting auxiliary circuit. Further, one of the main electrodes 2a and 7a of the arc tubes 1 and 6 is connected to one end of an AC power supply 12 via a ballast 11 composed of a choke coil by a common circuit, and the other main electrodes 2b and 7b are also of a common circuit. Is connected to the other end of the AC power supply 12.

When a power supply voltage is applied to the lamp, each arc tube starts discharge between the auxiliary main poles through the series circuit of the starting resistor 15 and the bimetal switch 16, but one of the arc tubes having a low starting voltage is started. For example, the arc tube 1 shifts to arc discharge and lights up. At that time, the bimetal switch 16 of the starting auxiliary circuit is opened by the radiant heat of the lighted arc tube 1, and the lamp voltage is not applied between the auxiliary main poles of the arc tubes 1 and 6. It should be noted that the same applies even if the light-emitting arc tube is reversed.

Although the arc tube for a mercury lamp has been described as the arc tube in the above embodiment, the arc tube for a metal halide lamp in which mercury and a metal halide are enclosed together with a starting auxiliary gas in the arc tube may be used. The lamp and the other may be an arc tube for a metal halide lamp. Also, three or more arc tubes may be used.

[0013]

As described above, in the high pressure discharge lamp according to the present invention, by providing the starting auxiliary circuit corresponding to a plurality of arc tubes, not only the starting is easy and reliable, but also the electrodes of the arc tube are deteriorated. Can be prevented and has a long life. Also, since one arc start circuit can reliably start two or more arc tubes and the arc tube mount structure can be simplified, it is possible to reduce the number of parts and welding points of the parts, and improve the lamp reliability. It has advantages such as improved productivity and cost reduction.

[Brief description of drawings]

FIG. 1 is a lighting circuit diagram of a high-pressure discharge lamp according to the present invention.

FIG. 2 is a lighting circuit diagram of a high pressure discharge lamp according to another embodiment of the present invention.

FIG. 3 is a lighting circuit diagram of a conventional high pressure discharge lamp.

[Explanation of symbols]

 1 arc tube 2a, 2b main electrode 3 auxiliary electrode 4 starting resistance 5 bimetal switch 6 arc tube 7a, 7b main electrode 8 auxiliary electrode 9 starting resistance 10 bimetal switch 11 ballast 12 AC power supply 15 starting resistance 16 bimetal switch

Claims (3)

[Claims] 1. An arc tube comprising a pair of main electrodes on both ends of a quartz tube, and an auxiliary electrode sealed in proximity to at least one of the main electrodes, and at least mercury being sealed together with a starting auxiliary gas therein. In a high pressure discharge lamp housed in a plurality of outer bulbs, a high voltage obtained by connecting the auxiliary electrode of the arc tube and its opposing main electrode through at least one starting auxiliary circuit consisting of a starting resistor and a bimetal switch. Discharge lamp. 2. A bimetal switch is used to disconnect the starting auxiliary circuit of a non-lit arc tube while the high-pressure discharge lamp having the arc tube having a plurality of starting circuits built therein is lit. Claim 1 characterized by
High-pressure discharge lamp according to the item. 3. A high-pressure discharge lamp having a plurality of arc tubes in one outer bulb, wherein the starting auxiliary circuit for the arc tubes incorporated in the lamp is one. High pressure discharge lamp.