JPH0449816Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a vehicle lighting device in which a discharge tube configured to generate a discharge in a mixed vapor of mercury vapor and metal halide vapor is enclosed within a glass bulb. This is related to the discharge of

[Prior art]

As this type of discharge tube, for example, a metal halide lamp is known. This metal halide lamp uses thallium iodide as the metal halide, and is more efficient than a simple mercury discharge tube.

This type of discharge tube has advantages over, for example, a halogen bulb, in that it is smaller, has greater luminous intensity, generates less heat, and has a longer life. Also, when the discharge condition is stable, the voltage is relatively low (for example, about 100V).
However, at the start of discharge, a high voltage (e.g.
It is necessary to supply 2000V to 15000V).

FIG. 3 shows a conventional example of a discharge lamp for a vehicle lamp using this type of discharge tube.

A discharge tube 1 is enclosed within a glass bulb 2.
3a and 3b are external lead-in lines.

The external lead-in wires 3a and 3b penetrate the sealing portion 2a of the glass tube 2 and are connected to the lug terminal 4.

5 is a cap that supports the glass tube 2.

[Problem that the invention attempts to solve]

In the conventional discharge lamp shown in FIG. 3, a high voltage of several thousand volts is applied to the external lead-in wires 3a and 3b at the start of lighting, so the glass tube sealing part 2
Electric leakage due to creeping discharge is likely to occur on the surface of a. If electrical leakage occurs, lighting will fail.

This idea was created in view of the above circumstances.
The purpose is to provide a discharge lamp for a vehicle lamp that is free from the risk of leakage caused by creeping discharge.

[Means for solving problems]

The discharge lamp according to the present invention, which was created to achieve the above object, is a vehicle lamp in which a discharge tube is enclosed in a glass bulb and has a structure that allows discharge to occur in a mixed vapor of mercury vapor and metal halide vapor. The external lead-in wire of the discharge tube is coated with an electrically insulating coating, including the part where the lead-in wire passes through the sealing part of the glass bulb, and the lead-in wire is made of glass. A portion of the bulb that protrudes outward from the sealed portion and is connected to the wire harness, and at least a portion of the sealed portion of the glass bulb are embedded in an inorganic electrically insulating material.

[Effect]

In the discharge lamp configured as described above, the external lead-in wire is coated with insulation from the part where it is sealed in the sealed part of the glass bulb to the part where it protrudes from the sealed part, and the protruding part is coated with insulation. Since the glass tube including the portion connected to the wire harness is embedded in the insulating material, there is no risk of creeping discharge occurring on the surface of the glass tube sealing portion.

〔Example〕

FIG. 1 is a partial sectional view of the discharge lamp of the present invention.
This embodiment (Fig. 1) is based on the conventional example (Fig. 3).
This is an example of improvement by applying the present invention to the third example.
The same drawing reference numbers as those in the drawings indicate the same or similar components as in the conventional example.

An electrically insulating material (water glass in this example) is applied to the portion where the external lead-in wires 3a, 3b penetrate the sealing portion 2a and the vicinity thereof, thereby forming an insulating coating 7a,
After forming the glass tube 7b, the opening of the glass tube 2 is sealed to form the sealed portion 2a. A perspective view of the vicinity of the sealing portion 2a at this stage is shown in FIG.

A wire harness 6 is connected to each of the external lead-in wires 3a and 3b (see FIG. 1). An inorganic electrically insulating material 8 is applied so as to cover the portions of the external lead-in wires 3a and 3b protruding from the sealing part, including the connection part, and the external lead-in wire protruding surface of the sealing part 2a.
(ceramic in this example).

As a result, the surface 2b where the creeping discharge occurred in the glass tube sealing part 2a in the conventional example is completely covered with the inorganic insulating material (filler) 8, so that the insulating effect of the insulating coatings 7a and 7b and the mutual dust Therefore, creeping discharge is completely prevented.

[Effect of idea]

As described in detail above, when the present invention is applied, there is no risk of leakage caused by creeping discharge, and it greatly contributes to improving the reliability of lighting operation.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of the present invention;
FIG. 2 is shown to explain the configuration of the above embodiment, and is a perspective view of the vicinity of the glass tube sealing portion. FIG. 3 is an external view of a conventional example. DESCRIPTION OF SYMBOLS 1...Discharge tube, 2...Glass tube bulb, 2a...Sealing part, 2b...Surface where there was a risk of creeping discharge occurring in the conventional example, 3a, 3b...External lead-in wire, 6
... Wire harness, 7a, 7b ... Insulation coating,
8...Inorganic electrically insulating filler.

Claims (1)

[Scope of utility model registration request] In a discharge lamp for a vehicle lamp in which a discharge tube structured to perform discharge in a mixed vapor of mercury vapor and metal halide vapor is enclosed in a glass bulb, the external lead-in wire of the discharge tube is sealed in the glass bulb. A part where the external lead-in wire, including the part that penetrates the sealing part, is coated with an electrically insulating coating, and the external lead-in wire protrudes outward from the sealing part of the glass bulb and is connected to the wire harness. and a discharge lamp for a vehicle lamp, characterized in that at least a part of the sealing part of the glass bulb is embedded in an inorganic electrically insulating material.