CN210040125U

CN210040125U - Short arc type discharge lamp

Info

Publication number: CN210040125U
Application number: CN201921012015.4U
Authority: CN
Inventors: 阪浩介; 寺田庄一
Original assignee: Ushio Denki KK
Current assignee: Ushio Denki KK
Priority date: 2018-08-07
Filing date: 2019-07-01
Publication date: 2020-02-07
Anticipated expiration: 2029-07-01
Also published as: JP2020024840A; CN110828287A

Abstract

Provided is a lamp structure capable of avoiding blackening of an arc tube caused by evaporation of a coil as a starting member without deteriorating the starting performance of a short arc type discharge lamp having a pair of electrodes arranged to face each other while being separated from each other in the arc tube. The electrode is characterized in that the electrode is composed of an electrode core wire and an electrode main body part with a large diameter formed at the front end of the electrode core wire, and a single-layer annular member is arranged in a manner of surrounding the electrode main body part.

Description

Short arc type discharge lamp

Technical Field

The present invention relates to a short arc discharge lamp for a projection projector, a projector, or the like, and more particularly to a short arc discharge lamp having an electrode provided with a member for starting.

Background

Currently, as a short arc type discharge lamp for the above-mentioned application, a short arc type discharge lamp in which a rare gas such as mercury or xenon gas is sealed in a light emitting tube is used.

As shown in fig. 5, the short arc type discharge lamp 1 includes a pair of

electrodes

3, 3 arranged in an arc tube 2 so as to be spaced apart from each other and face each other, and a halogen is sealed in the arc tube 2 in addition to mercury and a rare gas, so that blackening in the arc tube 1 is suppressed by a so-called halogen cycle.

In such a short arc type discharge lamp, a structure is known in which a coil is wound around an electrode as a starting member for improving startability. For example, japanese patent application laid-open No. 2004-362861 (patent document 1) shows a structure in which, as shown in detail in fig. 6, an electrode 3 is composed of a main body portion 5 and an electrode core wire 4, and a coil 6 composed of a linear tungsten is wound around the main body portion 5.

As shown in fig. 6 a, the coil 6 is formed by winding a coil made of linear tungsten on the main body portion 5 of the electrode 3 in multiple, and functions as a starting point (starting start position) of starting by a so-called void effect generated by a concave-convex shape between adjacent coils 6 at the time of starting lighting. Further, the coil 6 has a small diameter, and therefore is easily heated, and also has an effect of facilitating transition from glow discharge to arc discharge.

However, in recent years, under the situation where a higher output and a longer life of the lamp are demanded, it has been found that in such a shape in which the coil is wound, crater-like depressions are formed between the coils, and thus blackening of the lamp progresses, which is one of the causes of deterioration of the life.

As shown in fig. 6 (B), concentration of an electric field occurs in the gap formed between the adjacent coils 6, and discharge is initiated, whereby the coil 6 is overheated, tungsten evaporates to form the crater-like recess 7, and the tungsten evaporant W is directed toward the arc tube 2, and deposits on the inner wall surface of the arc tube 2 near the coil, and the deposition of the tungsten evaporant W continues to cause blackening 8.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-362861

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

In view of the above-described problems of the prior art, an object of the present invention is to provide a lamp structure capable of avoiding the occurrence of blackening due to evaporation of a coil as a starting member without deteriorating the starting performance of a short arc type discharge lamp.

Means for solving the problems

In order to solve the above problem, the short arc type discharge lamp according to the present invention is characterized in that the electrode is composed of an electrode core wire and an electrode body portion formed at a tip of the electrode core wire and thicker than the electrode core wire, and a single-layer ring-shaped member is provided so as to surround the electrode body portion.

Further, the electrode body has a diameter-expanded portion formed by expanding a diameter at a distal end thereof, and the annular member is provided on the electrode body at a position separated from the diameter-expanded portion.

Further, the annular member is formed to have a shape having a slit in a part in a circumferential direction.

Effect of the utility model

According to the short arc type discharge lamp of the present invention, since the single-layer annular member is provided in the main body portion of the electrode, the starting performance by the cavity effect is ensured by taking the gap between the annular member and the main body portion of the electrode as the generation region of the starting point discharge, and the evaporation of tungsten by the starting point electrons is directed not to the side of the wall surface of the envelope but to the side of the discharge space, so that the blackening of the wall surface of the envelope can be suppressed.

Drawings

Fig. 1 is a view showing an electrode structure of a short arc type discharge lamp according to the present invention.

Fig. 2 is a view of the electrode tip according to another embodiment of the present invention.

Fig. 3 is a side view showing the effect of the present invention.

Fig. 4 is a view of an electrode tip according to still another embodiment of the present invention.

Fig. 5 is an overall view of a conventional short arc type discharge lamp.

Fig. 6 is an enlarged cross-sectional view (a) of a main portion of fig. 5 and an explanatory diagram (B) of a failure.

Description of the reference symbols

1: short arc type discharge lamp

2: luminous tube

3: electrode for electrochemical cell

4: electrode core wire

5: electrode body part

5 a: expansion diameter part

10: ring-shaped member

11: welding mark

12: gap

W: (tungsten) evaporant

Detailed Description

Fig. 1 (a) is a side view of an electrode used in the short arc type discharge lamp of the present invention, and fig. 1 (B) is another example of an electrode having a different shape of an electrode main body portion.

In fig. 1 (a), the electrode 3 is composed of an electrode core wire 4 and a large-diameter electrode body 5 formed at the tip of the electrode core wire 4, and a ring member 10 is provided so as to surround the electrode body 5. The ring-shaped member 10 is a single-layer ring-shaped member made of tungsten wire, and has a substantially circular cross-sectional shape. The substantially circular shape herein includes not only a circular shape but also an elliptical shape.

Fig. 1 (B) shows an example in which the shape of the electrode body 5 is different, and in this example, the electrode body 5 further has an expanded diameter portion 5a that is expanded in diameter on the distal end side. The electrode structure described above corresponds to a large electric power.

In this example, the annular member 10 is provided on the electrode body 5 at a position separated from the diameter-expanded portion 5a formed by expanding the diameter of the tip of the electrode body 5. That is, the space between the expanded diameter portion 5a and the annular member 10 is separated to such an extent that the void effect does not occur, and the gap does not become a generation region of the starting point discharge.

In the embodiment of fig. 1 (B), it is understood that the separation distance between the expanded diameter portion 5a and the annular member 10 is preferably 0.04mm or more, and if it is smaller, blackening occurs.

Fig. 2 shows another example of the ring-shaped member 10, and in fig. 2 a, the ring-shaped member 10 is wound around the electrode main body portion 5 in a state of being slightly overlapped, and the overlapped portion is welded by laser or the like (identified as a welding mark 11).

The structure of fig. 2 (B) is a structure in which a part of the ring member 10 in the circumferential direction has a slit 12. The gap 12 is not a gap in which an electric field is concentrated in the gap therebetween to generate a spark, but a gap having a predetermined size is required, and more specifically, the gap is preferably 0.04mm or more.

Fig. 3 illustrates the operation and effect of the present invention, in which a gap is formed between the electrode body 5 of the electrode 3 and the annular member 10, and electric field concentration is generated in this region at the time of starting lighting, and ignition is generated at this portion to start lighting. Furthermore, the evaporant W of tungsten generated in this region is directed toward the axial direction of the electrode, rather than directly toward the inner wall surface of the light-emitting portion, and blackening due to deposition of the evaporant W can be suppressed.

The cross-sectional shape of the ring member 10 is not limited to a circular shape, and may be a rectangular shape as shown in fig. 4, or may be a polygonal shape (not shown) such as a hexagonal shape or an octagonal shape. The rectangular ring-shaped member 10 shown in fig. 4 is disposed so as to form a small gap between one side thereof and the electrode main body portion 5.

In this embodiment, similarly, electric field concentration occurs in a region of a small gap between the electrode main body 5 and the annular member 10, and ignition is started by generating a fire.

As described above, in the short arc type discharge lamp of the present invention, since the electrode is provided with the electrode constituted by the electrode core wire and the electrode main body portion having a large diameter formed at the tip thereof and the single-layer annular member is provided so as to surround the periphery of the electrode main body portion, electric field concentration occurs in the gap between the annular member and the electrode main body portion, and the ignition start is performed by the electric field concentration. The evaporant of tungsten generated in this region is directed toward the axial direction of the electrode and is not directed toward the inner wall surface of the arc tube, so that blackening due to deposition of the evaporant can be suppressed.

Claims

1. A short arc discharge lamp having a pair of electrodes disposed in a luminous tube so as to face each other while being spaced apart from each other,

the electrode is composed of an electrode core wire and an electrode main body part with a large diameter formed at the front end of the electrode core wire,

and a single-layer ring-shaped member is provided so as to surround the periphery of the electrode main body portion.

2. The short arc type discharge lamp according to claim 1,

the electrode body has a diameter-expanded portion formed by expanding a diameter at a distal end thereof, and the annular member is provided on the electrode body at a position separated from the diameter-expanded portion.

3. The short arc type discharge lamp according to claim 1 or 2,

the annular member has a shape having a slit in a part in a circumferential direction.