JPS5844528Y2 - metal halide lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal halide lamp comprising a metal halide sealed in an envelope, particularly a short arc type metal halide lamp.

In general, metal halide lamps have excellent color rendering properties, but since metal halide lamps have low vapor pressure, it is desirable for the temperature of the envelope to be high during lighting, so the envelope must be small. It is preferable to use a sealed body with one end sealed.

However, in the one-end sealed type enclosure, the remaining part of the exhaust pipe is formed in a state that protrudes outward from the other end wall, and when the light is turned on, this remaining part of the exhaust pipe becomes the lowest temperature part of the whole enclosure, and the temperature of this lowest temperature part becomes As a result, the vapor pressure of the enclosed metal halide is suppressed to a low level, so that even in a metal halide lamp equipped with a one-end sealed enclosure, it is still not possible to obtain good color rendering properties.

In particular, when the enclosure is downsized, the remaining portion of the exhaust pipe is formed relatively large, so the drawbacks due to the low temperature of this remaining portion of the exhaust pipe become significant.

In view of these circumstances, it is an object of the present invention to provide a metal halide lamp that can maintain a high temperature even in the remaining part of the exhaust pipe, which tends to become cold during lighting, and thus has excellent color rendering properties.

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

In the present invention, as shown in the figure, one end sealed type enclosure 1
A pair of metal foils 3, 3' are embedded in the crushing sealing part 2, and one internal lead rod extends from one metal foil 3 to the vicinity of the other end side in the sealing body 1 and bends or curves toward the center. 4 is formed with a coil portion 5 that extends toward the other end of the envelope 1 with the axis One discharge electrode 6 is supported by this coil portion 5 in such a manner that the coil portion 5 is wound around the other discharge electrode 6.
The rear end portion 6A is inserted into a recess 8 formed by the exhaust pipe remainder 7 formed at the center of the other end wall of the enclosure 1, or is further held by the inner peripheral surface of the recess 8, The one discharge electrode 6 is positioned, for example, on the axis X of the enclosure 1.

In addition, the other internal lead rod 4' extending into the enclosure 1 from the other metal foil 3' is arranged along the axis X of the enclosure 1, and the other discharge electrode 6' is provided at the tip thereof. Discharge electrode 6
, 6' are spaced apart from each other and face each other on the axis X, thereby constructing a metal halide lamp.

9 and 9' are external lead rods.

Since the metal halide lamp of the present invention has the above-mentioned configuration, the rear end 6A of one discharge electrode 6 is inserted into the recess 8 formed by the exhaust pipe remainder 7 of the envelope 1, so that no arc occurs during lighting. The remaining part 7 of the exhaust pipe is heated by the one discharge electrode 6, which becomes high temperature due to the generation of , and therefore the remaining part 7 of the exhaust pipe, which should be the lowest temperature part of the enclosure 1, can be brought to a high temperature state, and the enclosed metal halide can be heated. It is possible to vaporize reliably and greatly improve the color rendering properties, and also to promote heat dissipation of the one discharge electrode 6 and prevent it from falling into an overheating state.

Furthermore, by inserting the rear end 6A of one of the discharge electrodes 6 into the recess 8, the size of the enclosure 1 can be reduced, and in particular, the shoulder of the enclosure 1, which should be at a low temperature next to the rest of the exhaust pipe 7, can be made smaller. Since the distance between the portion 1A and the arc center becomes smaller, the entire sealed body 1 is heated to a more uniform temperature in these respects, and the color rendering properties are improved.

In addition to the above, the one discharge electrode 6 is located in the recess 8.
Since the position of the one discharge electrode 6 is regulated by , it is possible to easily arrange the position of the one discharge electrode 6 at the desired position (in the example shown in the figure, on the axis X).

Furthermore, in the illustrated example, by providing the coil portion 5 at the rear end 6A of the one discharge electrode 6, the heat radiation area is increased, and the heating efficiency of the remaining portion 6 of the exhaust pipe and the heat radiation efficiency of the discharge electrode 6 are increased. In particular, if the rear end portion 6A is held in contact with the inner surface of the recess 8 via the coil portion 5, the above-mentioned effect can be reliably obtained and the discharge of the one side can be The supporting force for the electrode 6 is increased, and vibration resistance can be improved.

By integrating the coil portion 5 with one of the internal lead rods 4 as in the illustrated example, manufacturing becomes easy and the length of one of the discharge electrodes 6 can be reduced. By making the front end (inner end) of the lead rod 5 follow one of the internal lead rods 4, it is possible to further reduce the distance between the shoulder portion 1A of the seal and the arc center.

As described above, according to the present invention, with an extremely simple configuration,
In a one-end sealed type enclosure, the parts that should be at a low temperature during lighting, including the rest of the exhaust pipe, can be maintained at a high temperature, and together with the ability to downsize the enclosure, the entire enclosure can be kept in a highly uniform high temperature state. As a result, the enclosed metal halide can be sufficiently vaporized, and a metal halide lamp with extremely excellent color rendering properties can be provided.

[Brief explanation of the drawing]

The figure is an explanatory longitudinal sectional front view of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...One end sealed type sealing body, 2...Crushing sealing part, 3゜3'...Metal foil, 4.4'...
...Internal lead rod, 5...Coil part, 6,6
'...Discharge electrode, 7...Remaining part of exhaust pipe,
8...Recess, 9,9'...External lead rod.

Claims (3)

[Scope of utility model registration request] (1) One end of the sealed enclosure is provided, and a pair of discharge electrodes are provided in the enclosure so as to be spaced apart from each other and face each other in the axial direction of the enclosure, and the other end of the enclosure is hollow. A metal halide lamp characterized in that a rear end portion of one of the discharge electrodes disposed on the side is inserted into a recess formed by the remaining portion of the exhaust pipe formed on the other end wall of the enclosure. (2) A utility model characterized in that a coil is formed on the outer peripheral surface of the rear end of the one discharge electrode, and a portion of the coil that continues to the front end constitutes a lead rod for the one discharge electrode. A metal halide lamp according to claim 1. (3) The metal halide lamp according to claim 1 or 2, wherein the rear end portion of the one discharge electrode is held in a recess formed by the remaining portion of the exhaust pipe. .