JPS63244548A - High pressure discharge lamp - Google Patents

Abstract

PURPOSE:To prevent fluctuation of a starting pulse voltage from being generated by providing a contact composed of thoria and tungsten at the contact of a starter and specifing the composition-quantities of this thoria and tungsten. CONSTITUTION:A fixed contact 11 is provided against the moving contact 10 of a bimetal, and when both contacts are forced to each other before starting, and a filament 8 for heating is energized and heated at starting, the bimetal 6 is bent and its moving contact 10 is separated from the fixed contact 11. In these contacts 10 and 11, a contact obtained by adding thoria to tungsten so as to make its composition to consist of 0.1-5wt.% thoria and 99.9-95.0wt.% of tungsten is employed. Accordingly, there is no deterioration on the surface of a contact caused by a high voltage and no fluctuation of a starting pulse voltage depending on an opening speed of a switch so that the starting pulse voltage can be stabilized.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a high pressure discharge lamp incorporating a starter.

[Prior Art] A thermally responsive starter, which is built into the outer bulb along with the arc tube to start a high-pressure sodium lamp by applying a pulse voltage, is equipped with a bimetal contact and a filament that heats the bimetal. These bimetallic contacts use tungsten contacts, which are heat resistant and durable, because when the contacts open, they generate a pulse voltage to start the lamp.

[Problems to be solved by the invention] The tungsten contacts of the starter mentioned above have the disadvantage that the contact surface becomes defective due to high voltage.
( ], ] W-Cu and W-C alloy contacts were not able to sufficiently improve the situation.For this reason, in conventional high-pressure sodium lamps with built-in starters, the surface condition of the bimetal contacts and the switch There was a problem in that large variations in starting pulse voltage occurred due to factors such as opening speed, causing damage to the ballast and wiring.

Therefore, the present invention provides a high-pressure discharge lamp in which a thermally responsive switch of the starter is configured so that the starting pulse voltage is stabilized.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a high-pressure discharge lamp in which a starter constituted by a thermally responsive switch and an arc tube are built into the outer bulb. TiO2)0.1~
5wt% (preferably 1-2vt%), tungsten 9
The starter is constructed of a thermally responsive switch using 9.9 to 95 wt% contacts.

[Function] The thermally responsive switch described above generates a high pulse voltage in the starting circuit to start the lamp when it is heated by the heating filament and opens the contact.
The tungsten contacts doped with 0.1 to 0.2 wt% of 2) are:
At high voltages, the surface condition does not deteriorate, and the pulse voltage does not vary depending on the opening speed of the switch, allowing good contact opening and closing. This stabilizes the starting pulse voltage, making it as stable as before. This will eliminate defects that can cause damage to equipment and wiring.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

Fig. 1 shows a starting circuit for a high-pressure sodium lamp installed in a starter using a thermally responsive switch, and Fig. 2 shows the relationship between the thermally responsive switch and the installation position of the heating filament.

In the first diagram, a portion 1 surrounded by a dotted line indicates an outer tube made of transparent hard glass in a high-pressure sodium lamp with an internal starter.The inside of this outer tube 1 is kept in a vacuum and the arc tube 2 Install the starter 3 surrounded by the chain line. This arc tube 2 is filled with high-pressure sodium vapor, and the starter 3
It is started by a discharge between the electrodes 4.5 and emits light.

The starter 3 includes a bimetal 6 constituting a thermally responsive switch, a switch contact portion 7, and a filament 8 for heating the bimetal.

The bimetal 6 of this heat-responsive switch has one end of the support 9 at point a, and the arc tube 2's voltage w! 4, and a movable contact 10 is provided at the other end of the bimetal tip, and the bimetal heating filament 8 has one end connected to the electrode 5 of the light emitting device 92 at point b, and the other end connected to the fixed contact 11. .

The switch contact part 7 has a movable contact 10 and a fixed contact 11 arranged to face each other, and before starting, the movable contact 10 is brought into contact with the fixed contact 11, and at the time of starting, the movable contact 10 at the tip is brought into contact with the fixed contact 11 by the operation of the bimetal 6. is arranged so that it is separated from the fixed contact 11.

Electricity of the luminous tube 2! ! A connection point a between the arc tube 2 and the bimetal support 9 is connected to a power supply terminal A, and a connection point a between the other electrode 5 of the arc tube 2 and the heating filament 8 is connected to a power supply terminal B via a ballast 12. 13 is a capacitor, and 14 is a power switch.

The bimetal 6 and the heating filament 8 constituting the thermally responsive switch are installed close to each other on a support 15 as shown in the second figure, and a fixed contact 11 is installed opposite the movable contact 10 at the tip of the bimetal. Before starting, both contacts are brought into contact, and when the heating filament 8 is energized and generates heat at the time of starting, the bimetal 6 is heated and bent, and the movable contact 10 at the tip of the bimetal operates so as to be separated from the fixed contact 11. This contact 10.11 is made by doping tungsten with thoria (TiO2) and 0.1 to 5 wt% thoria (preferably 1 to 2 wt%).
%), and a contact having a composition of 99.9 to 95.0 wt% tungsten is used.

In the high-pressure sodium lamp configured with a starter using a bimetal switch as described above, when the power switch 14 shown in FIG. The flow generates heat, which heats the bimetal 6 of the thermally responsive switch and pulls the movable contact 10 away from the fixed contact 11. The resulting high pulse voltage is applied to the arc tube 2, which lights up the high-pressure sodium lamp. Start.

At this time, the movable contact 10 and the fixed contact 11 set the tria to 0.
Because it is a tungsten contact with 1 to 5 wt% added,
The contact surface will not become defective due to high voltage, and the starting pulse voltage will not vary depending on the opening speed of the switch, so the starting pulse voltage will be stable.

According to the experimental results, the above-mentioned addition ratio of thoria is 1.
~2wt% is preferred, but it has been confirmed that within the range of 0.1~5wt%, large variations in starting pulse voltage due to factors such as the surface condition of the contact and the opening speed of the switch can be avoided. If it is less than 0.1wt%, the electron radiation property will be poor and the effectiveness of preventing fluctuations in pulse voltage will be reduced, and if it is more than 5wt%, the contact will become brittle.
Thoria is 0.1-5wt%, tungsten is 99.9-9
It is necessary that the composition be 5 wt%.

[Effects of the Invention] As described above, the present invention provides a high-pressure discharge lamp in which a starter equipped with a thermally responsive switch and an arc tube are built into the outer bulb.
Since the contacts of the thermally responsive switch are made of 0.1 to 5% truffle and 99.9 to 95% tungsten,
It is possible to prevent variations in the starting pulse voltage due to factors such as the surface condition of the contacts and the opening speed of the switch, and it is possible to eliminate the disadvantage of damaging the ballast and wiring, which was unavoidable in the past. be.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention, and FIG. 2 is a conceptual diagram of a thermally responsive switch. 1: Outer tube. 2: Arc tube, 3: Starter 6 6: Heat-responsive switch bimetal. Patent applicant: Toshiba Electric Materials Corporation (and one other person) Agent
Patent Attorney Oka 1) Kikuji Figure 1 Figure 2

Claims (1)

[Claims] In a high-pressure discharge lamp in which a thermally responsive starter and an arc tube are provided inside the outer bulb, a diaphragm of 0.1 to 5 W is applied to the contact part of the starter.
t% and 99.9 to 95 wt% tungsten.