JP2002075278A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a long-life discharge lamp which can prevent leaking from a sealing part in processing as well as a crack due to thermal strain. SOLUTION: A luminous tube 1 has a pair of electrodes 5, 6, and an elliptical luminous part 2 forming a discharge space which has sealing parts at both ends. At a non-luminous side of the sealing parts, non-sealing parts 11, 12 are arranged in contact with each other, and a glass tube for ultraviolet blocking consists of a central part 13 and holding parts 14, 15 arranged in contact with each both ends of the central part 13. The discharge lamp A is integrated with the luminous tube 1 inserted into the glass tube 16 and by welding the non- sealing parts 11, 12 with holding parts 14, 15 respectively.

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 headlight or the like.

[0002]

2. Description of the Related Art A conventional discharge lamp is provided with a discharge portion in which electrodes are opposed to each other, and sealing portions connected to both ends of the discharge portion. It has a configuration in which both ends of a blocking glass tube are sealed and integrated, and a discharge portion and a sealing portion are surrounded by an ultraviolet blocking glass tube (Japanese Patent Application Laid-Open No. 5-234568).

[0003]

However, in such a conventional discharge lamp, the discharge portion and the sealing portion are surrounded by an ultraviolet shielding glass tube, and both ends of the ultraviolet shielding glass tube and the sealing portion are sealed. Are sealed and integrated. Therefore, during the processing of the integration, the sealing portion of the arc tube once processed is again processed by heat, so that the molybdenum foil, which is the introduction foil sealed in the sealing portion, and the glass of the sealing portion. The hermeticity, that is, the hermeticity inside the sealing portion is impaired, causing a leak, which is a disadvantage. In addition, cracks due to thermal strain are generated by a heat cycle during lamp operation.

The present invention has been made to solve such a conventional problem, and has a long-life discharge capable of preventing leakage of a sealing portion during processing and preventing cracks due to thermal strain. It is intended to provide a lamp.

[0005]

DISCLOSURE OF THE INVENTION The discharge lamp of the present invention comprises:
A sealing portion is continuously provided at both ends of a light emitting portion having a pair of electrodes therein, and a tubular non-sealing portion is continuously provided on each anti-light emitting portion side of the sealing portion. Both ends of a glass tube for blocking ultraviolet light are fixed to each of the non-sealing portions, and the light emitting portion and the sealing portion are covered with the glass tube for blocking ultraviolet light.

With this configuration, the unsealed portion and both ends of the glass tube for blocking ultraviolet rays are fixed to each other.
The airtightness in the sealing portion is not impaired.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a discharge lamp according to an embodiment of the present invention will be described with reference to the drawings.

In the discharge lamp A according to the embodiment of the present invention shown in FIGS. 1 and 2, the arc tube 1 has a pair of electrodes 5 and 6 made of, for example, tungsten and has an ellipsoid which forms a discharge space. It has a light emitting section 2 having a shape, and sealing sections 3 and 4 at both ends of the light emitting section 2. A light emitting metal such as sodium or scandium is sealed in the light emitting portion 2 in the form of a halide together with xenon and mercury. Electrodes 5 and 6 are connected to one end of the sealing portions 3 and 4, and molybdenum foils 7 and 8 are sealed as introduction foils to which external lead wires 9 and 10 are connected to the other end. Sealing parts 3, 4
Non-sealing portions 11 and 12 having a tubular shape are continuously provided on the side opposite to the light emitting portion. An ultraviolet blocking glass tube 16 for blocking ultraviolet rays emitted from the light emitting tube 1 during lighting is provided at a central portion 13 surrounding the light emitting portion 2, at both ends of the central portion 13, and at a sealing portion 3. , 4 surrounding holding parts 14 and 15 which are narrower than the central part 13. Discharge lamp A is
As shown in FIG. 2, the arc tube 1 is inserted into the glass tube 16, and the unsealed portions 11, 12 of the arc tube 1 and the holding portions 14, 15 of the glass tube 16 are welded and integrated, respectively. I have. This makes it possible to obtain a discharge lamp in which the airtightness in the sealing portion is maintained.

Next, a method of manufacturing the discharge lamp according to the embodiment of the present invention will be described.

As shown in FIGS. 3 and 4, an arc tube 1 manufactured by a normal manufacturing method and a glass tube 16 for blocking ultraviolet rays are mounted on a normal glass lathe 28. The lathe 28 includes a headstock 29 on one side and a tailstock 33 on the other side.
And a collet chuck 34 for attaching the unsealed portion 12 to one of the tailstocks 33. The arc tube 1 is fixed by inserting the unsealed portion 11 into the collet chuck 30, and the unsealed portion 12 is fixed to the collet chuck 3.
4 and mounted in a lathe 28. The arc tube 1 is inserted into the glass tube 16 and is fixed to the glass tube fixing base 31. This glass tube fixing table 31
Is provided on the headstock 29 of the lathe 28, and the headstock 2
9 and around the shaft 32. The other end of the tailstock 33 is provided with a nitrogen supply pipe 36 for flowing nitrogen gas into the non-sealing portion 12 and a nitrogen discharge pipe 37 for discharging the nitrogen gas.
Is connected. A burner 38 and a processing jig 39 are provided adjacent to the holding portion 15 of the glass tube 16, and the burner 38 heats the region 41 of the limited peripheral surface of the holding portion 15 with a flame 40. The processing jig 39 is provided so as to be movable vertically with respect to the shaft 32.

The arc tube 1 fixed to the lathe 28 includes a lathe 2
The glass 8 rotates together with the lathe 28 by rotating about the shaft 32, and the glass tube fixing base 31 fixing the glass tube 16 also rotates around the shaft 32. A nitrogen gas is flowed into the non-sealed portion 12 while rotating the lathe 28. And
While the arc tube 1 is slowly rotated about the shaft 32 by the lathe 28 while flowing the nitrogen gas, the region 41 of the holder 15 is heated by the flame 40 until the quartz in the region 41 reaches the softening point. The processing jig 39 is stationary during this heating operation, but when the quartz in the region 41 is sufficiently softened, the processing jig 39 moves vertically toward the axis 32 as shown in FIG. Slowly pressurize and compress. Then, during this operation, the unsealed portion 12 also gradually softens,
Due to this softening, the holding portion 15 and the non-sealing portion 12 come into contact with each other and are welded. By this method, the holding portion 15 and the non-sealing portion 12
Can be reliably welded.

The following method may be performed following the method for manufacturing a discharge lamp according to the embodiment of the present invention. That is, when the holding portion 15 and the non-sealing portion 12 come into contact with each other due to softening and start welding, the non-sealing portion 12 is further compressed by the processing jig 39 until the non-sealing portion 12 becomes slightly smaller than the original outer diameter. The processing jig 39 is separated.
At the same time as the processing jig 39 is separated, the nitrogen discharge pipe 37 is closed, the internal pressure of the non-sealing part 12 is increased by nitrogen gas, and the non-sealing part 12 in the softened region 41 is gradually expanded. When the outer diameter of the unsealed portion 12 returns to the original state, the flame 40 is stopped, the nitrogen discharge pipe 37 is opened, and the internal pressure is returned to the original state.
Is completed. By this method, the holding portion 15 and the non-sealing portion 12 can be securely and firmly welded.

The holding unit 1 is formed by the above-described methods.
5 and the non-sealing portion 12 are welded,
The arc tube 1 is removed from 0, 34, and the arc tube 1 is rotated by 180 ° about the light emitting unit 2, and as shown in FIG. After being fixed to the collet chuck 30, respectively, a nitrogen gas is flown into the non-sealing portion 11, and the above-described operation is repeated for the non-sealing portion 11 of the arc tube 1 and the holding portion 14 of the glass tube 16. The discharge lamp A according to the embodiment of the present invention described above can be obtained.

When forming the discharge lamp A, as shown in FIG. 6, an exhaust pipe 35 for evacuating the inside of the glass tube 42 or filling the glass tube 42 with an inert gas is attached to the ultraviolet light blocking glass tube 42. And the unsealed part 1 of the arc tube
After welding the holding portions 14 and 15 of the glass tube 42 to the inside of the glass tube 42, the inside of the glass tube 42 is evacuated or filled with an inert gas or the like, and the exhaust tube 35 is squeezed or using a normal method. Alternatively, the inside of the glass tube 42 may be sealed.

FIGS. 7 and 8 show a headlamp discharge lamp device B of an application example using the discharge lamp A according to one embodiment of the present invention.

An unsealed portion 11 of a discharge lamp A as shown in FIG. 1 is inserted into a base 21 and supported. The external lead wire 9 of the discharge lamp A passes through the base 21 and is connected to a cylindrical metal terminal 19 provided on the side opposite to the discharge lamp. The external lead wire 10 of the discharge lamp A is connected to one end of a power supply line 23, and the other end of the power supply line 23 penetrates through the base 21 and has a cylindrical shape provided on the side opposite to the discharge lamp of the base 21. Are connected to the metal terminal 20 of the first embodiment. The metal terminals 19 and 20 have a high withstand voltage insulated wire 1.
7, 18 are connected respectively. Power supply line 2
3 is covered with a ceramic sleeve 22 and a stopper 24 is fixed to the power supply line 23. The concave portion 25 of the base 21 is used to secure a withstand voltage between the connecting portions between the insulated wires 17 and 18 and the metal terminals 19 and 20.
A partition 26 is integrally formed with the base 21 and is filled with a synthetic resin, for example, silicone rubber 27 so as to cover each connection part. Thus, a long-life headlamp discharge lamp device can be obtained.

Although the central portion 13 and the holding portions 14 and 15 at both ends of the glass tube 16 have different inner and outer diameters, the glass tube 16 may have a straight tube shape having the same diameter. The arc tube 1
A vacuum may be applied between the glass tube 16 and the space, or nitrogen or argon may be sealed therebetween.

[0018]

As described above, according to the present invention, it is possible to prevent leakage of a sealing portion during processing, prevent cracks due to thermal strain, and reduce radiation of ultraviolet rays from a discharge lamp. It is possible to provide a discharge lamp having a long service life.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a partially cutaway front view showing an example of an apparatus for implementing a method of manufacturing a discharge lamp according to an embodiment of the present invention.

FIG. 4 is an enlarged front view of the same main part.

FIG. 5 is also a partially cutaway front view.

FIG. 6 is a front view for explaining a case where an exhaust pipe is used as a glass tube for blocking ultraviolet rays.

FIG. 7 is a perspective view of a headlamp discharge lamp device B of an application example using a discharge lamp A according to an embodiment of the present invention.

FIG. 8 is a partially cutaway front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 3, 4 Sealing part 11, 12 Non-sealing part 16 Glass tube for blocking ultraviolet rays

Claims (1)

[Claims] 1. A light-emitting portion having a pair of electrodes inside, a sealing portion is continuously provided on both ends, and a cylindrical non-sealing portion is continuously provided on each side of the sealing portion opposite to the light-emitting portion. A discharge lamp, wherein both ends of a glass tube for blocking ultraviolet light are fixed to each of the non-sealed portions, and the light emitting portion and the sealed portion are covered with the glass tube for blocking ultraviolet light. .