JP2956725B2 - Discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp used for an automobile headlamp or the like.

[0002]

2. Description of the Related Art Conventionally, in this type of discharge lamp,
A cylindrical ferrule is used, and the outer lead wire of the arc tube and the insulated wire made of the high-voltage covered wire are positioned from both openings inside the cylindrical base, and the outer lead wire and the insulated wire are connected to each other. Then, in order to prevent dielectric breakdown between the connection parts, the inside of the base on the arc tube side is filled with silicone rubber,
In order to prevent the gas released from the silicone rubber from adhering to the surface of the arc tube during the operation of the discharge lamp and to prevent the quartz glass, which is the arc tube material, from becoming cloudy, the surface of the silicone rubber is heat-resistant inorganic cement. It is covered with.

However, in such a conventional discharge lamp, since the heat-resistant inorganic cement covering the surface of the silicon rubber cannot provide perfect airtightness, the gas released from the silicon rubber during the operation of the discharge lamp is not available. Cannot be sufficiently prevented from adhering to the surface of the arc tube and recrystallizing a high-temperature portion of quartz glass as a material of the arc tube to attenuate the luminous flux.

[0004]

Accordingly, the inventor of the present invention has provided a discharge lamp having a structure in which a partition wall is provided in a cylindrical base in a direction perpendicular to the axis thereof, and silicon rubber is filled in a base recess opposite to the arc tube. Was considered. That is, a pair of cylindrical metal terminals are fixed to the counter-emission tube side of the partition wall of the base, and one external lead wire and a power supply line connected to the other external lead wire are inserted into each metal terminal, Each cylindrical metal terminal is cut slightly below both ends to form a thick portion in the cut portion of the metal terminal, and the thick portion allows each of the metal terminal, the external lead wire, and the power supply line to be cut. After connecting one end of each of the insulated wires inserted into the holes of the disc-shaped lid to the metal terminals and pulling the other end out of the base, the base recess on the side opposite to the arc tube A discharge lamp with a structure filled with silicon rubber and closed with a disk-shaped lid was manufactured and studied. However,
Even with such a configuration, since it is difficult to completely close the gap between the cylindrical metal terminal and the external lead wire and the power supply line, gas released from the silicon rubber adheres to the surface of the arc tube through the gap. However, it has not been possible to completely prevent the problem that the luminous flux is attenuated due to recrystallization of the arc tube and cloudiness.

[0005] The present invention provides a discharge lamp capable of preventing gas released from silicon rubber from adhering to the surface of an arc tube and suppressing a decrease in luminous flux maintenance factor.

[0006]

DISCLOSURE OF THE INVENTION The discharge lamp of the present invention comprises:
An arc tube is supported on one end side, and a cap to which one end of a pair of cylindrical metal terminals is fixed is provided in a concave portion on the other end side, and one external lead wire of the arc tube and the other external lead wire are provided. The connected power supply lines are respectively inserted into the metal terminals, the other end portions of the metal terminals are melted and closed, and connected to the one external lead wire and the power supply line. The recesses are filled with silicon rubber so as to be connected to the respective terminals and pulled out of the base, so as to bury the connection between the metal terminal and the insulated wire in the recess of the base.

[0007]

According to the present invention, one of the external lead wires and the power supply line of the arc tube is inserted into the cylindrical metal terminal, and the other end of the metal terminal is melted and closed, so that the metal terminal and one of the two terminals are fused. Since the external lead wire and the power supply line are connected, the gas released from the silicone rubber flows to the arc tube side through the gap between the cylindrical metal terminal and the arc tube external lead wire and the power supply line during the operation of the discharge lamp. As a result, recrystallization of the arc tube surface can be prevented without leakage.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a metal halide lamp according to an embodiment of the present invention includes an arc tube 1 and a base 2 as main parts. The luminous tube 1 has electrodes 3 and 4 sealed at both ends of a quartz glass tube, and a luminous metal such as sodium, scandium or the like is enclosed therein in the form of a halide together with xenon and mercury. A base body 5 made of a synthetic resin, for example, PPS (polyphenylene sulfide), a cylindrical body 6 made of a synthetic resin attached to the base body 5, and a disk-shaped lid 7 made of a synthetic resin for closing an opening of the cylindrical body 6 And a concave portion 8 is formed therein. One end of the arc tube 1 is firmly supported by the arc tube support plates 19 and 20 at one end of the base body 5, and a pair of cylindrical metal terminals 9 and 10 is arranged at the other end thereof.
Is planted at one end. Power supply lines 13 connected to the external lead wires 11 and 12 of the arc tube 1 are inserted through the metal terminals 9 and 10. The power supply line 13 is covered with a ceramic sleeve 18.
The other ends of the metal terminals 9 and 10 are melted and closed by plasma welding or the like, and the external lead wire 11 and the power supply wire 13 are connected. The metal terminals 9 and 10 are connected to insulated wires 14 and 15 having high withstand voltage. The metal terminals 9, 10 and the insulated wires 14,
Silicon rubber 16 is filled so as to cover the respective connection portions 15. The insulated wires 14 and 15 are drawn out of the base 2 through holes provided in the lid 7. Lid 7
Is fixed to the entire base 5 with screws 17 (see FIGS. 2 and 3) or the like to close the opening of the cylindrical body 6. The filling of the silicon rubber 16 into the concave portion 8 is necessary to ensure the dielectric strength between the conductive metal portions exposed in the concave portion 8. If the silicon rubber 16 is not used, the creepage distance between the conductive metal portions is required. Must be sufficiently long, and the base body 5 becomes extremely large. The screen cap 21 is attached to the arc tube base body 5.

As described above, in the metal halide lamp according to the embodiment of the present invention, the external lead wire 11 and the power supply wire 13 of the arc tube 1 are inserted into the cylindrical metal terminals 9 and 10, and both ends of the metal terminals 9 and 10 are connected. By fusing and closing the ends, the arc tube 1 and the silicone rubber 16 can be hermetically isolated from each other, thereby preventing the gas emitted from the silicone rubber 16 from clouding the arc tube 1. . Also,
The use of the silicone rubber 16 can prevent the base body 5 from becoming large.

[0011]

As described above, according to the present invention,
It is possible to provide a discharge lamp in which the quartz glass surface of the arc tube is not recrystallized by the gas released from the silicon rubber during the lamp movement and does not become cloudy, and a decrease in the luminous flux maintenance ratio can be suppressed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a discharge lamp according to an embodiment of the present invention.

FIG. 2 is also a bottom view

FIG. 3 is an exploded perspective view of the same.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 arc tube 2 base 8 recess 9, 10 metal terminal 11, 12 external lead wire 13 power supply line 14, 15 insulated wire 16 silicon rubber

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01J 5/50

Claims (1)

(57) [Claims] An arc tube is supported on one end side, and a cap to which one end of a pair of cylindrical metal terminals is fixed is provided in a concave portion on the other end side, one external lead wire of the arc tube and the other. The power supply lines connected to the external lead wires are respectively inserted into the metal terminals, the other end portions of the metal terminals are melted and closed, and connected to the one external lead wire and the power supply line, and the insulation is performed. Each of the covered electric wires is connected to the metal terminal and drawn out of the base, and silicon rubber is filled in the recess so as to bury a connection portion between the metal terminal and the insulating covered wire in the recess of the base. A discharge lamp.