JP3216111B2 - Metal halide lamp - Google Patents

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 metal halide lamp, and more particularly to an improvement of a metal halide lamp using a starting auxiliary circuit comprising a non-linear ceramic capacitor as a starter in the lamp.

[0002]

2. Description of the Related Art In a metal halide lamp having a built-in non-linear ceramic capacitor as a starter, the circuit configuration of the starter is improved so that the characteristics of the capacitor are not deteriorated during the operation of the lamp. No. 3-116687 is disclosed.

FIG. 9 is a circuit diagram of a conventional metal halide lamp having a starting circuit in the lamp. In the figure, reference numeral 11 denotes an arc tube for a metal halide lamp, and main electrodes 12a, 1 are provided at both ends.
2b is sealed, and the auxiliary electrode 13 is sealed in the vicinity of at least one of the main electrodes 12a, and a metal halide is sealed inside together with a starting auxiliary gas. Also, the auxiliary electrode 13
A starting circuit in which a resistor 14 and a bimetal switch 15 are connected in series is provided between the main electrode 12b and the main electrode 12b opposed to the starting electrode. A series circuit of a non-linear ceramic capacitor 16 and a semiconductor switch 17 is connected via a second bimetal switch 18 in parallel with the arc tube 11.
A resistor 19 (Rc) is connected in parallel with the series circuit of the nonlinear ceramic capacitor 16 and the semiconductor switch 17, and a resistor 20 (Rs) is connected in parallel with the semiconductor switch 17.

When a power supply voltage is applied, a pulse voltage is generated by the starter, and the pulse is applied between the main electrode 12a and the auxiliary electrode 13, and between the main electrodes 12a and 12b.
Then, first, a glow discharge occurs between the main electrode 12a and the auxiliary electrode 13, and then an arc discharge occurs between the main electrodes 12a and 12b. As described above, since discharge starts from the narrow gap between the main electrode 12a and the auxiliary electrode 13, 1K
It can be started easily with a relatively low pulse voltage of about V.

FIG. 10 is another circuit diagram of a conventional metal halide lamp. In FIG. 10, reference numeral 21 denotes an arc tube for a metal halide lamp, in which main electrodes 22a and 22b are sealed at both ends, and are located near at least one main electrode 22a. The auxiliary electrode 23 is sealed with a metal halide together with a starting auxiliary gas. The main electrode 2 facing the auxiliary electrode 23
2b, a starting circuit in which a resistor 24 and a bimetal switch 25 are connected in series is provided. A series circuit of a nonlinear ceramic capacitor 26 and a semiconductor switch 27 is connected in parallel with the arc tube 21 via the bimetal switch 25. Further, a resistor 28 (Rs) is connected in parallel with the semiconductor switch 27.

When a power supply voltage is applied, a pulse voltage is generated by the starter, and the pulse is applied between the main electrode 22a and the auxiliary electrode 23 and between the main electrodes 22a and 22b.
Then, first, a glow discharge occurs between the main electrode 22a and the auxiliary electrode 23, and then an arc discharge occurs between the main electrodes 22a and 22b. As described above, since discharge starts from the narrow gap between the main electrode 12a and the auxiliary electrode 13, 1K
It can be started easily with a relatively low pulse voltage of about V.

As described above, the conventional metal halide lamp with a built-in starter has two or more contacts as a starting auxiliary circuit. In FIG. 9, two bimetal switches are used, and in FIG. Uses one bimetal switch. Here, the starting auxiliary circuit is provided with two or more electrical contacts for the following reasons. The first reason is that no potential is applied to the auxiliary electrode while the lamp is lit. This is because if a potential difference occurs between the auxiliary electrode and the adjacent main electrode, the metal halide in the arc tube decomposes and corrodes the quartz glass near the electrode.

[0008]

According to the present invention, a pair of main electrodes is provided at the end of a quartz tube, and an auxiliary electrode is sealed in the vicinity of at least one of the main electrodes. And a starting auxiliary circuit in which a non-linear ceramic capacitor and a semiconductor switch are connected in series in an outer sphere, wherein the starting auxiliary circuit comprises one main part of the arc tube. connected between the auxiliary electrode close to the electrode and the main electrode, or
Also, there is no need to disconnect
A voltage is applied to the linear ceramic capacitor, and a resistor Rc having a resistance value selected from 10 kΩ to 100 kΩ is connected in parallel with the auxiliary circuit.

[0009]

For the above reasons, two or more electric contacts are provided in the starting auxiliary circuit, but another problem arises. First, the lamp will not start unless the two electrical contacts of the starting assist circuit are closed,
There is a drawback in that the variation in the contact pressure of the bimetal switch increases the variation in the lamp restart time.
When two contacts are switched by one bimetal switch as shown in FIG. 10, one contact is made of a tungsten coil, but malfunctions often occur due to vibration of a lamp or the like. Furthermore, the structure has a complicated structure due to having two or more contacts, and the capacity of the outer bulb is limited, which makes it difficult to downsize the lamp.

[0010] The present invention has been made in view of the above, and can greatly improve the life characteristics of a lamp having at least a starting auxiliary circuit comprising a non-linear ceramic capacitor as a built-in starter of a metal halide lamp.
By using the nonlinear ceramic capacitor,
Provide a metal halide lamp that can start a lamp having a high starting voltage with a relatively low pulse voltage, can improve lamp starting characteristics, has a good production yield, has a long life, is easy to start, and has a long life. The purpose is to:

[0011]

SUMMARY OF THE INVENTION According to the present invention, a pair of main electrodes and an auxiliary electrode are sealed close to at least one of the main electrodes at the ends of a quartz tube, and a metal halide together with a starting auxiliary gas is contained therein. In a metal halide lamp in which a sealed arc tube and a starting auxiliary circuit in which a nonlinear ceramic capacitor and a semiconductor switch are connected in series are housed in an outer sphere, the starting auxiliary circuit includes one main electrode of the arc tube. And an auxiliary electrode adjacent to the main electrode, and a resistor Rc having a resistance value of 10 KΩ to 100 KΩ which is not disconnected in an electric circuit during lamp operation and is selected in parallel with the auxiliary circuit. It is characterized by connecting.

[0012]

According to the above configuration, only one electrical contact needs to be provided in the starting auxiliary circuit, and there is no variation in starting. In addition, a high pulse voltage is applied by the non-linear ceramic capacitor, and the starting of the lamp becomes easy and reliable. Further, by selecting the resistance value of the resistor in an appropriate range, not only can various characteristics of the non-linear ceramic capacitor be secured, but also a sufficient pulse voltage can be applied.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a circuit diagram of a metal halide lamp according to the present invention. In FIG. 1, reference numeral 1 denotes an arc tube for a metal halide lamp in which main electrodes 2a and 2b are sealed at both ends of a quartz glass tube.
An auxiliary electrode 3 is sealed in proximity to at least one of the main electrodes 2a, and mercury and a metal halide are sealed therein together with a starting auxiliary gas. A starting circuit in which a resistor 4 and a bimetal switch 5 are connected in series is provided between the auxiliary electrode 3 and the opposing main electrode 2b.
And a series circuit of a non-linear ceramic capacitor 6 and a semiconductor switch 7 are connected in parallel. A resistor 8 (Rc) is connected in parallel with the series circuit of the nonlinear ceramic capacitor 6 and the semiconductor switch 7, and a resistor 9 (Rs) is connected in parallel with the semiconductor switch 7.

When the power supply voltage is applied, a pulse voltage is generated by the starter, and the pulse is applied between the main electrode 2a, the auxiliary electrode 3, and the main electrodes 2a and 2b. And
First, after a glow discharge occurs between the main electrode 2a and the auxiliary electrode 3, an arc discharge occurs between the main electrodes 2a and 2b.
As described above, since the discharge starts from the narrow gap between the main electrode 2a and the auxiliary electrode 3, it can be easily started with a relatively low pulse voltage of about 1 kV. Here, 4 functions as a starting auxiliary resistance. Resistor 8 reduces the voltage applied to the non-linear ceramic capacitor during lamp operation,
Further, in order to prevent the deterioration of the characteristics by flowing a pyroelectric current generated when the capacitor exceeds the Curie temperature, a resistor generates heat at the time of lamp failure and conducts this heat to the capacitor to generate a pulse. Functions as a resistance for stopping. Further, the resistor 9 functions as a resistor for aligning the phases of the generated pulse voltages.

In the starting assist circuit as described above, when the lamp is turned on, the voltage applied to the non-linear ceramic capacitor is defined by the resistance value of the resistor 8. Therefore, Table 1 shows the relationship between the resistance value of the resistor 8 and the peak value of the voltage applied to the capacitor. The voltage waveform diagrams are shown in FIGS.

[0016]

[Table 1]

Note that, in the peak values of the voltages shown in Table 1, a pulse-like waveform was ignored. As is clear from Table 1, the voltage applied to the nonlinear ceramic capacitor during lamp operation can be reduced by lowering the resistance value of the resistor 8. This is because the voltage between the auxiliary electrode 3 and the main electrode 2a can be reduced by bypassing the current flowing from the auxiliary electrode 3 to the resistor 8.

Next, specific experimental examples will be described.
The initial characteristics shown in FIG. 1 are a metal halide lamp having a lamp power of 400 W, a lamp voltage of 130 V, and a lamp current of 3.3 A and a circuit configuration. The resistance of the resistor 4 is 100 kΩ, and the resistance of the resistor 9 (Rs) is 30 kΩ. Resistor 8 (R
The resistance value of c) is 1 MΩ, 500 kΩ, 200 kΩ, 10 kΩ.
When the lamp was constructed under the conditions of 0 kΩ and 30 kΩ, and the change in the pulse voltage generated by the non-linear ceramic capacitor with the elapse of the lamp lighting time was measured, the results shown in FIG. 8 were obtained. The lighting conditions are as follows: lighting for 7 hours, turning off for 1 hour.

As is apparent from FIG. 8, when the resistance value of the resistor 8 is larger than 200 KΩ, the pulse voltage becomes 1 KV or less before the elapse of 8000 hours, the starting characteristic of the lamp deteriorates, and the intended purpose is achieved. Can not do. On the other hand, by setting the resistance to 100 KΩ or less, 1
The pulse voltage of 1 KV or more could be maintained even after lighting for 0000 hours, the non-linear ceramic capacitor did not deteriorate, and the life characteristics were good. However, if the resistance value is set to 10 KΩ or less, the generated pulse voltage becomes 900 V or less, causing variations in starting and deteriorating starting characteristics. As described above, by selecting the resistance value of the resistor 8 in the range of 10 KΩ to 100 KΩ, one electric contact of the starting auxiliary circuit can be provided, and starting is easily and reliably performed by using a non-linear ceramic capacitor. be able to.

In the experimental example, the resistance value of the resistor 4 is set to 1
The case where the resistance value of the resistor 9 is 00 KΩ and the resistance value of the resistor 9 is 30 KΩ has been described.
Even when KΩ and the resistance value of the resistor 9 are set to 15 KΩ to 100 KΩ, the resistance value of the resistor 8 is set to 10 KΩ to 100 KΩ.
In this case, the pulse voltage generated by the nonlinear ceramic capacitor was 1 KV or more, and the startability was good.

[0021]

As described above, in the metal halide lamp according to the present invention, a non-linear ceramic capacitor is generated by reducing the number of electrical contacts of the starting auxiliary circuit and by regulating the resistance of the resistor within a predetermined range. Therefore, it is possible to easily and reliably start the lamp. Further, there is an advantage that the lighting components used in the starting auxiliary circuit do not deteriorate throughout the lamp life period, and the lamp life characteristics are good.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a circuit configuration of a metal halide lamp according to the present invention.

FIG. 2 is a diagram showing a voltage waveform of a nonlinear ceramic capacitor when a resistance value of a resistor 8 is set to infinity.

FIG. 3 is a diagram showing a voltage waveform of a non-linear ceramic capacitor when the resistance value of the resistor 8 is 1 MΩ.

FIG. 4 is a diagram showing a voltage waveform of the nonlinear ceramic capacitor when the resistance value of the resistor 8 is set to 500 KΩ.

FIG. 5 is a diagram showing a voltage waveform of the nonlinear ceramic capacitor when the resistance value of the resistor 8 is set to 200 KΩ.

FIG. 6 is a diagram showing a voltage waveform of the nonlinear ceramic capacitor when the resistance value of the resistor 8 is set to 100 KΩ.

FIG. 7 is a diagram showing a voltage waveform of the nonlinear ceramic capacitor when the resistance value of the resistor 8 is set to 30 KΩ.

FIG. 8 is a characteristic diagram showing a change in a pulse voltage generated by a non-linear ceramic capacitor with a lapse of a lighting time of a lamp in which a resistance value of a resistor 8 is changed.

FIG. 9 is a lighting circuit diagram of a conventional metal halide lamp.

FIG. 10 is another lighting circuit diagram of a conventional metal halide lamp.

11 is a voltage waveform diagram generated between a main electrode and an auxiliary electrode when a bimetal switch is opened during lighting of the conventional metal halide lamp shown in FIG.

FIG. 12 is a lamp voltage waveform diagram in FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube for metal halide lamp 2a, 2b Main electrode 3 Auxiliary electrode 4 Resistance 5 Bimetal switch 6 Non-linear ceramic capacitor 7 Semiconductor switch 8 Resistor (Rc) 9 Resistor (Rs)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 41/14-41/234

Claims (1)

(57) [Claims] 1. A luminous tube comprising a pair of main electrodes at an end of a quartz tube, an auxiliary electrode sealed in proximity to at least one of the main electrodes, and a metal halide sealed together with a starting auxiliary gas therein. In a metal halide lamp in which a starting auxiliary circuit in which a non-linear ceramic capacitor and a semiconductor switch are connected in series is housed in an outer sphere, the starting auxiliary circuit is close to one main electrode of the arc tube and the main electrode. Connect between the auxiliary electrode and the electric circuit while the lamp is on.
Non-linear ceramic capacitor without disconnection
A metal halide lamp characterized by applying a voltage and connecting a resistor Rc having a resistance of 10 kΩ to 100 kΩ in parallel with the auxiliary circuit.