JPH10149802A - Metal halide lamp - Google Patents

Abstract

(57) [Abstract] (with correction) [Problem] By simply applying a relatively low pulse voltage to an arc tube, starting can be easily performed by ionization and excitation of a discharge gap, and no discharge in the outer sphere occurs. The present invention provides a versatile metal halide lamp having a long life and a lighting posture that can be arbitrarily selected. SOLUTION: An arc tube 1 is supported in an outer bulb 8 having a base 7 at one end, and nitrogen, neon, argon, krypton or xenon gas is sealed in the outer bulb as a single substance or a mixture,
A pulse generating circuit is provided by a starter 3 in the outer sphere, a discharge gap 12 made of a bimetal 5 connected in parallel to the arc tube and arranged in the outer sphere, and a current reducing resistor 13 for reducing the discharge to a small current. Are connected in series, the interval between the discharge gaps made of bimetal is specified to be 0.2 to 0.8 mm, and the arc tube is started by ionization and excitation based on glow discharge generated by energizing the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in starting characteristics of a metal halide lamp, and more particularly to an improvement in a discharge gap disposed in an outer sphere.

[0002]

2. Description of the Related Art As an HID lamp, a metal halide lamp in which a metal halide is sealed together with mercury and a rare gas in an arc tube in which electrodes are sealed is used. An E39 type base is used as a base for this type of lamp. In this base, the lighting pulse is desirably about 2.0 kV.
Both ID lamps were designed within this standard, and mercury lamps and high-pressure sodium lamps had satisfactory starting characteristics. This is because the lamp is started by applying a high-voltage pulse voltage by using thorium oxide or the like as the electron-emitting substance of the electrode.

However, in the case of a lamp having a high starting voltage, such as a metal halide lamp in which a metal halide is sealed in a quartz arc tube, a lamp in which auxiliary electrodes are sealed at both ends of the arc tube together with a main electrode at least in proximity to at least one of them. Although the starting probability is about 20 to 40% even with the above-mentioned pulse voltage, it is extremely reduced to 5 to 10% in a lamp not using the auxiliary electrode. This is because hydrogen having a high electronegativity contained in the quartz tube, which is a material for the arc tube, captures free electrons and generates hydrogen iodide during lamp operation. For this reason,
Even if a high-voltage pulse voltage is applied, the starting performance is poor, and the probability of starting is reduced.

[0004] Therefore, it is necessary to add other energy to facilitate starting. As a representative method, there is a method of encapsulating a radioisotope such as promethium within the arc tube ⁽¹⁴⁷ Pm) and krypton ⁽⁸⁵ Kr). This can improve the start-up characteristics because the necessary free electrons are supplied in excess. However, in addition to using a thoriated tungsten electrode containing thorium oxide, which is a radioisotope, applying thorium oxide to the electrode or enclosing thorium, promethium or krypton in the arc tube as an additive Can easily turn on the lamp, but there is a problem in management and treatment of radioisotopes in the manufacture of the arc tube.

[0005]

[Problems to be Solved by the Invention]
As disclosed in Japanese Patent Publication No. 018, a method of irradiating ultraviolet rays to facilitate starting of the arc tube has been proposed. However, arranging a source of ultraviolet light near the arc tube in the outer sphere has a problem that not only its support is difficult but also the cost increases.

The present inventor has previously proposed a metal halide lamp in which a discharge gap is connected in parallel with an arc tube in an outer bulb filled with nitrogen gas or the like. This is because glow discharge is generated between discharge gaps during pulse generation in an inert gas atmosphere such as nitrogen gas in the outer sphere without irradiating ultraviolet rays having high energy to easily start the arc tube. The arc tube is started by the action of ionization and excitation of the discharge gap. The reason for this is that the startability is considered to be affected by the intensity of the energy of the emission spectrum and the wavelength width of the spectrum, rather than the start-up improvement by ultraviolet rays, and the discharge gap serves as an external auxiliary electrode. Guessed. That is, by applying a high pulse from the ballast side and applying a small amount of discharge energy from the outside, lighting can be instantaneously performed.

[0007] This means that it is not necessary to irradiate the arc tube with strong energy such as ultraviolet light in order to easily start the arc tube. Further, since hydrogen iodide does not exist in the outer sphere unlike in the arc tube, glow discharge is facilitated, and the discharge can promote arc discharge between the main electrodes of the arc tube.

The present invention has been made in view of the above, and in order to improve the starting characteristics of a metal halide lamp, without using a radioisotope in an arc tube as in the prior art,
Also, the ionization of the discharge gap can be achieved simply by applying a relatively low pulse voltage to the arc tube without using an auxiliary electrode or the like.
It is an object of the present invention to provide a long-life metal halide lamp which can be easily started by an excitation action and does not generate discharge in the outer sphere. It is another object of the present invention to provide a versatile metal halide lamp in which the lighting position of the lamp can be arbitrarily selected because no auxiliary electrode is used.

[0009]

In order to achieve the above-mentioned object, the present invention provides a method for supporting an arc tube in an outer sphere having a base at one end, and containing nitrogen, neon, argon, krypton or xenon gas in the outer sphere. And a pulse generating circuit with a starter in the outer sphere, and a discharge gap made of a bimetal connected in parallel to the arc tube and arranged in the outer sphere. A current-reducing resistor for making a small current is connected in series, and the interval between the discharge gaps made of the bimetal is defined as 0.2 to 0.8 mm,
The arc tube is started by an ionizing / exciting action based on a glow discharge generated by energizing the gap.

[0010] Further, an arc tube is supported in an outer sphere having a base at one end, and nitrogen, neon, argon, krypton or xenon gas is enclosed in the outer sphere alone or in a mixture, and a starter in the outer sphere is provided. A pulse generation circuit,
A discharge gap connected in parallel to the arc tube and arranged in the outer sphere, and a current reducing resistor for reducing the discharge to a small current are connected in series, and the interval between the discharge gaps is 0.2 to 2.0 m.
m, characterized in that the arc tube is started by an ionization / excitation effect based on a glow discharge generated by energizing the gap.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a metal halide lamp according to the present invention, and FIG. 2 is a circuit configuration diagram. In the figure, reference numeral 1 denotes an arc tube made of quartz glass, main electrodes 2a and 2b are sealed at both ends, and argon gas, mercury, scandium iodide, and sodium iodide are sealed therein. A heat insulating film is provided on the outer periphery of the arc tube around the electrodes. Reference numeral 3 denotes an internal starter (starter in a lamp) connected in parallel to the arc tube 1 and includes an auxiliary start resistor 4, a bimetal switch 5, and a glow discharge tube 6. A pair of arc tube posts 10a and 10b are fixed to a stem 9 in a hard glass outer ball 8 having a base 7 at one end, and one of the posts 10b is brought into contact with the tip of the outer ball 8 to emit light. Both ends of the tube are held and supported in the outer sphere. The electrical connection of the arc tube electrode is made via a lead wire 11.

A series circuit of a discharge gap 12 made of bimetal and a current reducing resistor 13 is connected in parallel with the resistor 4 and the bimetal switch 5 of the starter. These discharge gaps and the like are welded to the side surface of the arc tube support 11A, and are arranged so as to form a gap with a part of the lead wire 11. And this interval is 0.2-0.8
It is specified in the range of mm.

As shown in FIG. 1, in the lamp according to the present invention, a discharge gap is provided near the arc tube in parallel with the arc tube, and the nitrogen filling pressure in the outer bulb is 46,600 pa or 1: 1 of nitrogen and argon gas. 46,600pa of mixed gas of 1
And the distance of the discharge gap is 0.3 mm.

Next, the experimental results including comparative examples will be described. As a conventional lamp, when a lamp with a tube input of 250 W was tested with a lamp voltage of 180 V and a wiring length of 50 m, if the ambient temperature was 10 ° C., all the lamps could be turned on for 10 samples by the pulse voltage of the glow discharge tube. However, when the ambient temperature became -10 ° C, only four lights were turned on. In order to improve this, it is necessary to remove the mercury and iodide from adhering to the auxiliary electrode and bring the auxiliary electrode closer to the main electrode, but there is a limit due to the variation due to the pinch seal.

Therefore, unlike the lamp structure shown in FIGS. 1 and 2 according to the present invention, the auxiliary electrode is not sealed at the end of the arc tube, and the discharge between the auxiliary poles is not performed inside.
Discharge was performed in the outer sphere. Nitrogen gas or the like is sealed in the outer sphere at a predetermined pressure. To discharge the gas, the gap of the discharge gap is preferably about 0.2 to 0.8 mm, and a flow reduction resistance of about 15 kΩ is connected in series with this. Connected. In the case of FIGS. 1 and 2, a bimetal having a discharge gap of about 0.3 mm is arranged. Then, after lighting, the bimetal separates due to the heat of the arc tube. Also, since it can be started by glow discharge in the outer sphere,
No auxiliary electrode is required and no ceramic resistor is required.

Next, as in the lamp according to the present invention, a discharge gap was connected in parallel with the arc tube, a glow discharge was generated at the time of pulse generation, and how the lamp was started was examined. First, using a device that causes glow discharge to measure the amount of ultraviolet rays, a measuring tube having electrodes sealed at both ends of an input of 150 W is filled with 10 mg of mercury + 6,650 pa of argon gas, and the other is filled with 13,13 g of nitrogen gas.
300 pa was sealed and measured in a dark room. When the spectrum diagram was analyzed, it was confirmed that the lamp in which the nitrogen gas according to the present invention was sealed hardly emitted ultraviolet light.

This is because, as shown in the spectrum table on pages 31 and 32 of the Discharge Handbook, edited by the Institute of Electrical Engineers of Japan, published in 1974, there are four strong spectra of mercury up to a wavelength of 380 nm. There is no emission with nitrogen gas. The inventor of the present invention refers to the description on page 33 of the above-mentioned document, and if a glow discharge based on nitrogen gas is generated, photons and ions are generated by the ionization and excitation action. It was confirmed that starting was possible without irradiation. Further, since it is arranged in the outer sphere, it is not affected by an impurity gas such as hydrogen halide which hinders discharge.

Further, specific experimental examples will be described.
Table 5 shows the results of measuring the start-up time delay after the generation of a glow pulse by preparing five lamps each of six types and a lamp having a conventional structure and the lamp of the present invention in which nitrogen gas was sealed in the outer bulb shown in FIG. Such a result was obtained. The ambient temperature is 0 ° C
The applied voltage is 180 V and the wiring length is 50 m. (Hereinafter, margin)

[0019]

[Table 1]

As apparent from Table 1, the present invention is related to the present invention.
With lamps of specifications No. 2 to 4, the lamp can be turned on almost instantaneously.

Next, a second embodiment of the present invention will be described with reference to FIG.
And FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals. Main electrodes 2a and 2b are sealed at both ends of an arc tube 1 made of quartz glass, and argon gas and mercury, scandium iodide and sodium iodide are sealed therein. Is attached.
An internal starter 3 (starter in the lamp) is connected in parallel to the arc tube 1, and includes an auxiliary start resistor 4, a bimetal switch 5, and a glow discharge tube 6. And cap 7 on one end
A pair of arc tube struts 10a and 10b are fixed to a stem 9 in an outer sphere 8 made of hard glass having
b is in contact with the tip of the outer sphere 8 and holds both ends of the arc tube to be supported in the outer sphere. The electrical connection of the arc tube electrode is made via a lead wire 11.

A parallel circuit of a discharge gap 21 and a current reducing resistor 22 is connected in parallel with the resistor 4 and the bimetal switch 5 of the starter. These discharge gaps and the like are welded to the side surfaces of the arc tube support 11a, and the nickel wires 24a and 24b are fixed on the aluminum plate 23 at predetermined intervals through a brazing material such as silver so as to face the discharge gap. It is formed and arranged. And this interval is 0.2 ~
It is specified in the range of 2.0 mm.

Further, specific experimental examples will be described.
As shown in FIG. 3, in a metal halide lamp in which metal halides of Sc and Na are sealed in an arc tube, the starting characteristics of a conventional lamp (specification No. 1) and a lamp of the present invention (specification No. 2) are five by five. It was measured. As is clear from Table 2, the lamp of the present invention could be easily turned on. The conditions at this time are: an ambient temperature of 0 ° C .; an applied power supply voltage of 180 V;
0 m.

[0024]

[Table 2]

As described above, the glow discharge is generated between the discharge gaps in the outer sphere to facilitate the start of the arc tube. For this purpose, the interval of the discharge gap is selected within a predetermined range.
If a material having good startability is selected as the constituent material, instantaneous lighting becomes possible. Further, in the above embodiment, nitrogen gas and a mixed gas of nitrogen gas and argon gas were described as the sealed gas in the outer sphere, but other neon gas, argon gas, krypton gas or xenon gas may be used alone or as a mixed gas. Almost the same effect is observed. However, the use of neon gas or argon gas alone may cause discharge in the outer sphere and must be excluded. Further, a nonlinear ceramic capacitor or the like may be used instead of the glow discharge tube as the pulse generating circuit in the outer sphere.

[0026]

As apparent from the above description, the metal halide lamp according to the present invention has a discharge gap at a predetermined interval with nitrogen gas or the like sealed in the outer bulb, and a pulse is generated from the internal starter by turning on the power. Occasionally, the ionization / excitation effect based on glow discharge in the atmosphere facilitates starting even at a low pulse voltage, and there is no need to enclose a radioactive isotope or excess mercury as in the conventional case. Sufficient measures can be taken for conservation. Further, there is an advantage that a safe and reliable countermeasure is taken against an unexpected accident of the lamp, and a metal halide lamp having a long life and an arbitrary lighting posture can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a metal halide lamp according to the present invention.

FIG. 2 is also a circuit configuration diagram.

FIG. 3 is a side view of another metal halide lamp according to the present invention.

FIG. 4 is a circuit configuration diagram of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 2a, 2b Main electrode 3 Internal starter 4 Starting auxiliary resistance 5 Bimetal switch 6 Glow discharge tube 7 Base 8 Outer sphere 9 Stem 10a, 10b Arc tube support 11 Lead wire 12 Discharge gap 13 Discharge resistance 21 Discharge gap 22 Downflow resistance

Claims (2)

[Claims] An arc tube is supported in an outer sphere having a base at one end, and nitrogen, neon, argon, krypton or xenon gas is sealed in the outer sphere alone or in a mixture, and a starter in the outer sphere is provided. Metal halide lamp comprising a pulse generation circuit according to the above, a discharge gap made of a bimetal connected in parallel to the arc tube and arranged in the outer sphere, and a current reducing resistor for making the discharge a small current are connected in series. And
The gap of the discharge gap made of the bimetal is 0.2 to
A metal halide lamp defined as 0.8 mm, wherein the arc tube is started by an ionization / excitation action based on a glow discharge generated by energizing the gap. 2. A luminous bulb is supported in an outer sphere having a base at one end, and nitrogen, neon, argon, krypton or xenon gas is sealed in the outer sphere as a single substance or a mixture, and a starter in the outer sphere is provided. In a metal halide lamp comprising a pulse generation circuit according to the above, a discharge gap connected in parallel with the arc tube and arranged in the outer bulb, and a current-reducing resistor for making the discharge a small current are connected in series, A metal halide lamp characterized in that an interval of a discharge gap is defined to be 0.2 to 2.0 mm, and an arc tube is started by an ionization / excitation action based on a glow discharge generated by energizing the gap.