JP3418716B2 - High pressure steam discharge lamp - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure vapor discharge lamp using a translucent alumina tube as an arc tube. [0002] Translucent alumina tubes have the property of being stable against alkali metals, and are used for arc tubes of high-pressure sodium lamps. In recent years, metal halide lamps using a translucent alumina tube as an arc tube for enclosing a metal halide have been commercialized in a class of 150 W or less. The advantage of using an alumina tube in a metal halide lamp is that it is more chemically and thermally stable with respect to a metal halide as an enclosure than quartz glass generally used in a conventional metal halide lamp. The disadvantage of the conventional metal halide lamp made of quartz that the lamp life is shortened by a chemical reaction between the fill and the quartz glass can be suppressed, and the life characteristics can be expected to be improved. [0004] Further, the design of a lamp with high efficiency utilizing the characteristic that the use limit temperature is higher than that of quartz glass has been realized.
An arc tube made of quartz glass has an advantage that alkali metal can be sealed, which cannot be sealed because of high reactivity. By the way, lamps with a built-in starter include:
There are a high pressure sodium lamp with a built-in starter in which sodium metal is sealed in a translucent alumina tube, and a metal halide lamp with a built-in starter in which a metal halide is sealed in an arc tube made of quartz. Lamps incorporating these starters can be used for lighting with inexpensive ballasts for mercury lamps, and thus are widely used in various applications in the field of lighting. FIG. 2 shows a circuit example of a conventional high-pressure vapor discharge lamp with a built-in starter. In FIG. 2, 1 is an arc tube, 2 is a resistor, 3 is a glow tube that opens and closes, 4 is a normally closed bimetal switch, and these constitute a starter. Reference numeral 5 denotes a tungsten filament connected in series to the starter. The starter and the tungsten filament 5 constitute a starting circuit, and this starting circuit is connected in parallel with the arc tube 1. Reference numeral 6 denotes a proximity auxiliary conductor, which is provided in contact with the arc tube 1 and has one end connected to a lead wire 8 between the arc tube 1 and the tungsten filament 5. The proximity auxiliary conductor 6 has a function of lowering the voltage required for inter-electrode discharge by creating an electric field between the electrodes having the opposite potential and promoting the dielectric breakdown of a starting gas such as argon or mercury vapor. This is for reducing the starting voltage of the lamp and facilitating the start of lighting. As the proximity auxiliary conductor, a wire or coiled filament of a heat-resistant metal such as molybdenum is generally used. These are incorporated in an outer sphere (not shown) maintained in a high vacuum, and a high pressure vapor discharge lamp with a built-in starter is configured. When such a high-pressure vapor discharge lamp with a built-in starter is connected to a power supply via a ballast (not shown), a series circuit comprising a resistor 2, a glow tube 3, a bimetal switch 4, and a tungsten filament 5 is formed. Although current flows, the current is turned on and off by opening and closing operations of the glow tube 3, and the lamp is started and lit by a pulse voltage induced in the ballast due to this transient phenomenon. While the lamp is on, the bimetal switch 4 is opened by the heat of the lamp, the starting circuit is disconnected, and the current to the resistor 2 and the glow tube 3 is cut off. In the above-described high-pressure vapor discharge lamp, the end portion of the lamp using a translucent alumina tube as an arc tube is hermetically sealed by brazing, but is sealed from the sealed portion at the end of life. Things may leak. If the leakage from the arc tube leaks into the outer bulb, which is kept in a high vacuum, the lamp voltage will drop, the current flowing through the ballast will increase, and the ballast will fail or burn out. is there. Tungsten filament 5 is arranged to prevent failure and burning of the ballast. That is, when the filling leaks from the arc tube into the outer bulb due to leakage, thermoelectrons are emitted from the tungsten filament heated by energization, and a part of the gas leaked into the outer bulb is released. Ionized. Then, a discharge is generated between the tungsten filament 5 and a location (lead wire 7) which is a potential counter electrode by the ionized gas, and a part of the tungsten filament 5 is melted. When the tungsten filament 5 is blown, the current to the glow tube 3 is cut off, so that the generation of the pulse voltage is stopped and the lamp is not turned on. However, in the above-mentioned conventional high-pressure vapor discharge lamp with a built-in starter, when the enclosure leaks from the arc tube, the influence of the leakage amount and the ambient temperature. As a result, the lamp may be turned on even when the tungsten filament is melted and no pulse voltage is generated. Especially when the leak amount is relatively small and the ambient temperature is high, start-up lighting is easy. If the lamp lights up in the leaked state, an overcurrent will flow through the ballast,
May cause burnout. This is due to the fact that the proximity auxiliary conductor 6 is still electrically connected, and the function of lowering the lamp starting voltage and facilitating the start of lighting is alive. The present invention is to provide a safe and easy-to-use metal vapor discharge lamp that has solved such problems. A high-pressure vapor discharge lamp according to the present invention includes an arc tube, a proximity auxiliary conductor attached to the arc tube, and a starting circuit connected in parallel to the arc tube in an outer bulb. The arc tube is made of a translucent alumina tube and has at least metal halide, mercury and inert gas sealed inside.
Tungsten filaments that are blown when the enclosure leaks from the arc tube are connected in series, and one end of the proximity auxiliary conductor is connected between the starter and the tungsten filament. Features. The starter uses at least one of a glow tube, a combination of a bimetal switch and a heating element, and a non-linear capacitor to generate a pulse with the connected ballast. Also includes those connected to bimetal switches that are not directly involved in resistance and pulse generation. According to the high-pressure vapor discharge lamp according to the present invention, one end of the proximity auxiliary conductor is connected between the starter and the tungsten filament connected in series,
When the leakage from the arc tube causes the leakage of the filling material into the outer bulb and the tungsten filament blows, the proximity auxiliary conductor is also electrically disconnected, and the function of lowering the lamp starting voltage and facilitating the start of lighting is stopped. , The lamp no longer ignites. As a result, the conventional metal vapor discharge lamp
It is possible to provide a safe and easy-to-use metal vapor discharge lamp which can solve the problem that the lamp is turned on in the state of leakage of the enclosure from the arc tube and the overcurrent causes the breakdown and burnout of the ballast. Hereinafter, the present invention will be described with reference to examples.
FIG. 1 is a circuit diagram showing an embodiment of a high-pressure vapor discharge lamp according to the present invention, in which 1 is a light emitting tube made of a translucent alumina tube, 2 is a resistor, 3 is a glow tube for opening and closing operation, and 4 is normally closed. Is a bimetal switch, 5 is a tungsten filament, and 6 is a proximity auxiliary conductor. Inside the arc tube 1, metal halides such as dysprosium iodide, holmium iodide and thulium iodide, mercury, and an inert gas such as argon gas are sealed. A resistor 2, a glow tube 3, and a bimetal switch 4 connected in series constitute a starter, and a tungsten filament 5 is connected in series with the starter to constitute a starter circuit. This starting circuit is connected to the arc tube 1 in parallel.
Reference numeral 6 denotes a proximity auxiliary conductor, which is provided adjacent to the arc tube and has one end provided with a starter and a tungsten filament 5.
Connected between These are assembled in an outer bulb (not shown) made of hard glass kept in a high vacuum to form a high pressure vapor discharge lamp with a built-in starter. When this high pressure vapor discharge lamp with a built-in starter is connected to a power supply via a ballast, a current flows through a series circuit composed of the resistor 2, the glow tube 3, the bimetal switch 4, and the tungsten filament 5, and the glow tube The switching operation of 3 causes the current to be turned on and off. A pulse voltage induced in the ballast is generated by the transient phenomenon at this time, and the lamp is turned on. While the lamp is lit, the heat causes the bimetal switch 4 to be kept open, so that the starting circuit is disconnected and the current to the glow tube is cut off. If such a lamp has been used for a long period of time, the enclosure may leak from the arc tube. In such a case, when the lamp is turned on, the gas leaked into the outer sphere of the high vacuum is ionized by thermions emitted from the heated tungsten filament 5 as described above,
This triggers a discharge between the tungsten filament 5 and the lead wire 7 having a potential opposite polarity, and a part of the tungsten filament 5 may be blown.
As a result, the current to the glow tube 3 is cut off, the generation of the pulse voltage is stopped, and the lamp is not turned on. Even in such a situation, in the conventional one, as shown in FIG. 2, one end of the proximity auxiliary conductor 6 is connected to the support wire 8 between the arc tube 1 and the tungsten filament 5, The proximity auxiliary conductor 6 was still functioning. However, in the present invention, one end of the proximity auxiliary conductor provided for the purpose of lowering the starting voltage of the lamp and facilitating lighting is connected between the bimetal 4 and the tungsten filament 5, so that the proximity auxiliary conductor 6 is formed. The lamp starting voltage rises because it is completely disconnected electrically and ceases its function. As a result, the lamp can be turned off without being affected by the leakage amount of the arc tube or the ambient temperature. As described above, according to the present invention,
When the arc tube leaks, the lamp can be reliably turned to a faulty state, so that a high-safety high-pressure steam discharge lamp can be obtained that prevents breakdown and burning due to overcurrent flowing through the ballast. .

[Brief description of the drawings] FIG. 1 is a circuit diagram showing one embodiment of a high-pressure vapor discharge lamp of the present invention. FIG. 2 is a circuit diagram showing an example of a conventional high-pressure vapor discharge lamp. [Explanation of symbols] 1 arc tube 2 Resistance 3 glow tube 4 Bimetal switch 5 Tungsten filament 6. Proximity auxiliary conductor 7, 8 lead wire

Continuation of the front page (56) References JP-A-57-109295 (JP, A) JP-A-58-30061 (JP, A) JP-A-61-54149 (JP, A) JP-A-63-141255 (JP, A) , A) Shokai Sho 57-125479 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 61/54

Claims (1)

(57) [Claim 1] A high-pressure vapor discharge vessel in which an arc tube, a proximity auxiliary conductor attached to the arc tube, and a starting circuit connected in parallel to the arc tube are incorporated in an outer bulb. In the electric lamp, the arc tube is made of a translucent alumina tube, and at least metal halide, mercury and inert gas are sealed inside, and the starter circuit leaks the enclosure from the starter and the arc tube If
A high-pressure vapor discharge lamp characterized in that a tungsten filament that melts into the filament is connected in series, and one end of the proximity auxiliary conductor is connected between the starter and the tungsten filament.