JP2002075281A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp with a structure/shape endowed with strong anti-crack property based on a relation with a shape of a step part at an electrode sealing part of the lamp and generation of a crack while the lamp is lit with the stepped part as a starting point. SOLUTION: With the discharge lamp constituting an electrode sealing part continuously composed of glass cylinder parts with enlarged diameter from a small-diameter part to a large diameter part fitted at both ends of a glass tube part with a center part swelling, and at same time, discharging a given wavelength of ultraviolet rays by an arc discharge with a cathode and an anode set face to face inside the glass tube part, the junction part of the small- diameter parts 3a, 3'a supporting electrode reed bars 2a2, 2'a2 of the both electrodes 2a1, 2'a1 through bead tubes 3a1, 3'a1 and the large diameter parts 3b, 3'b sealing and supporting metal foils 3b2, 3'b2 feeding electricity to the both electrodes through bead bars 3b1, 3'b1 is formed to have a tilting face of 20 to 60 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp such as a short arc discharge lamp for optically processing a work such as a semiconductor, a liquid crystal or a printed circuit board. The present invention relates to a discharge lamp having excellent properties.

[0002]

2. Description of the Related Art Various types of discharge lamps that emit ultraviolet light of a predetermined wavelength by arc discharge have been proposed.
One example is a short arc discharge lamp. The configuration of the electrode sealing portions located at both ends of the short arc type discharge lamp is substantially the same on both the anode side and the cathode side, and therefore, description will be given here with reference to FIG. 6A showing only the anode side. An electrode sealing portion 100 of a conventional short arc type discharge lamp includes an electrode 101, an electrode lead rod 102 for supplying electricity to the electrode 101, and a bead tube 103 for supporting the electrode lead rod 102 through the hole. And the electrode lead rod 10
2 is welded to an end opposite to the electrode 101 side, and a metal foil 106 for supplying power to the electrode 101 via an electrode lead rod 102, and the metal foil 106 is sealed between a seal tube 105. The main part is composed of a bead rod 104 to be supported and a seal tube 105 for welding and fixing these from outside.

A bead tube 103 installed in a small-diameter portion of a glass tube portion that expands from a small-diameter portion to a large-diameter portion and receives a high pressure while the discharge lamp is on is a seal tube 105 at the end of the discharge lamp.
To the welding of the inner surface and made firm, the discharge lamp structure to reduce the pipe diameter D _S to the limit capable of maintaining the mechanical strength to withstand the high pressure of the sealed vapor (gas) it is taken during operation . On the other hand, a bead rod 104 that supports a plurality of metal foils 106 installed in the large diameter portion of the glass tube along the side surface.
Is to secure a sufficient space between the metal foils 106 to make the seal tube 1
Structure and larger tube diameter D _L for sealing improvement have been taken by the sufficient welding implementation of the 05 of the inner surface and the outer surface of the bead rod 104.

For this reason, the electrode sealing portion 100 which corresponds to the joint between the small diameter bead tube 103 and the large diameter bead rod 104 is provided.
Has a stepped portion TP as shown in FIG. 6B. The shape of the stepped portion TP is a portion that is likely to cause a variation in shape due to a variation in the method because it is formed by melting glass. As a result, conventionally, a discharge lamp having a gradual step shape as shown in FIG. 7A and a steep step shape as shown in FIG. 7B has been manufactured and provided. Conventionally, as a method of reducing the variation in the individual shape of the step portion TP, as shown in FIG. 6B, an inclined surface TS is provided on an end surface of the bead rod 104 on the bead tube 103 side, and the inclined surface TS is provided.
A method of suppressing the variation in the shape by setting the angle has been taken.

[0005]

However, the relationship between the shape of the step TP and the product performance has not been studied in detail. In addition, a crack starting from the step portion TP of the electrode sealing portion 100 may occur during the lighting of the discharge lamp, and there may be some causal relationship between the shape of the step portion TP and the occurrence of the crack. He was suspected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of forming a stepped portion of an electrode sealing portion of a discharge lamp, and a crack during lighting of the discharge lamp starting from the stepped portion. It is an object of the present invention to provide a discharge lamp having a structure and a shape having strong crack resistance based on the relationship with occurrence of cracks.

[0007]

According to the first aspect of the present invention, the diameter of the glass tube bulb is expanded from a small diameter part to a large diameter part at both ends of a glass tube bulb part bulging at the center. In a discharge lamp that continuously forms a glass tube portion to form an electrode sealing portion, and that is provided so that a cathode and an anode are opposed to each other in the glass tube bulb portion and emits ultraviolet light of a predetermined wavelength by arc discharge. The joint portion between the small-diameter portion supporting the electrode lead rods of the two electrodes via a bead tube and the large-diameter portion sealingly supporting a metal foil for supplying power to the two electrodes via a bead bar is referred to as 20. The discharge lamp was formed so as to have a slope of about 60 degrees.

As described above, the joint between the small-diameter portion and the large-diameter portion of the glass tube portion is formed so as to have a slope of 20 to 60 degrees, so that the electrode sealing portion of the discharge lamp is formed. It is possible to provide a discharge lamp having a shape of a step portion of an electrode sealing portion having strong crack resistance based on a relationship between a shape of the step portion and occurrence of cracks during lighting of the discharge lamp starting from the step portion.

According to a second aspect of the present invention, there is provided a discharge lamp, wherein the inclined portion formed by the electrode-side end face of the bead rod and the side face of the bead rod is formed by 20
And 45 degrees.

As described above, the inclined portion of the bead rod is set to 2
By manufacturing using a member formed to have an angle of 0 to 45 degrees, the shape of the step portion of the electrode sealing portion having strong crack resistance can be easily formed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a discharge lamp according to the present invention will be described with reference to FIG. As shown in FIG. 1, a discharge lamp 1 according to an embodiment of the present invention has a glass tube portion 2 in which a center swells and a metal vapor or an inert gas is sealed therein, and a glass tube portion. An anode 2a1 and a cathode 2'a1 are provided so as to be opposed to each other, and a glass tube portion which expands at both ends of the glass tube portion 2 from small diameter portions 3a, 3'a to large diameter portions 3b, 3'b. Are continuously formed in the electrode sealing portions 3, 3 '.
And

The two electrodes 2 are provided in the electrode sealing portions 3 and 3 '.
electrode lead rods 2a2 for supplying electricity to a1,2'a1
2'a2, bead tubes 3a1, 3'a1 supporting the electrode lead rods 2a2, 2'a2 through the holes, and electrode leads protruding from the bead tubes 3a1, 3'a1 on the side opposite to the electrode side. The ends are welded to the rods 2a2, 2'a2,
metal foils 3b2, 3'b2 for supplying power to a1,2'a1 via electrode lead rods 2a2, 2'a2;
Bead rods 3b1 and 3'b1 for sealingly supporting 3'b2 with the seal tubes 4 and 4 'are housed, and these are welded and fixed by the seal tubes 4 and 4' from the outside.

Further, the small diameter portion 3 of the electrode sealing portions 3, 3 '
a, 3'a and the large diameter portions 3b, 3'b
Steps SP, SP 'having an angle of intersection with the axis of 20 to 60 degrees
It is formed so that it becomes. Metal terminal boxes 5, 5 'for supplying power supplied from the power supply lead wires 6, 6' to the metal foils 3b2, 3'b2 are connected to the rear side of the electrode sealing portions 3, 3 '. ing. Further, the electrode-side end faces of the bead rods 3b1 and 3'b1 and the bead rod 3b
Angle θ of inclined portion SP1 formed with the side surface of 1,3′b1
₂ is formed so that the intersection angle with the axis becomes 20 degrees to 45 degrees.

Here, step portions SP, SP ', which are joint portions between the small diameter portions 3a, 3'a of the electrode sealing portions 3, 3' and the large diameter portions 3b, 3'b, are defined as axial lines. 20 degrees to 6 degrees
The reason for setting the angle to 0 degrees will be described below. Since the anode side and the cathode side of the discharge lamp 1 have substantially the same structure, only the anode side will be described below.

[Quantification of the shape of the stepped portion of the electrode sealing portion of the discharge lamp] The stepped portion SP as shown in FIGS. 2 (a) and 2 (b)
Angle theta _1, were digitized and quantified by measuring the angle theta ₂ of the inclined portion SP1 of the beads stick 3b1.

[Process in which cracks are generated while the discharge lamp is lit at the stepped portion of the electrode sealing portion of the discharge lamp] The surface temperature of the discharge lamp 1 when the discharge lamp 1 is lit depends on the filling in the tube. 500 ° C ~ for complete evaporation and efficient light emission
It is kept at 800 ° C. Almost all of the heat generated by the discharge lamp 1 depends on the glass tube portion 2.

The heat energy generated in the glass tube part 2 is
Some of the heat is conducted to the air around the glass tube portion 2, but the heat conducted to the electrode sealing portion 3 of the discharge lamp 1 is conducted to the small diameter portion 3a of the electrode sealing portion 3 and the step is formed. Conduction is conducted to the large-diameter portion 3b of the electrode sealing portion 3 through the portion SP.

Therefore, the temperature of the step SP corresponding to the portion where the thermal resistance changes rapidly generates a temperature difference ΔT as shown in FIG. If this temperature difference ΔT is large, the step S of the electrode sealing portion 3
At the interface of P, a difference in body expansion occurs between the glass and the components in the electrode sealing portion 3 due to the temperature difference ΔT, and stress is generated near the interface of the electrode sealing portion 3 to cause cracks.

FIG. 4A shows a surface temperature difference per unit length with respect to the angle θ ₁ of the step portion SP of the electrode sealing portion 3. According to this, as described above, as the shape of the step SP becomes steeper (the angle θ ₁ becomes larger), the surface temperature difference ΔT at the step SP of the small diameter portion 3a and the large diameter portion 3b tends to increase. Therefore, the thermal stress generated in the step SP of the electrode sealing portion 3 is larger as the angle θ ₁ is larger (as the step is steeper).
It is thought that there is a tendency to increase.

As the lighting time of the discharge lamp 1 elapses,
Due to this thermal stress, strain is accumulated in the glass of the step portion SP of the electrode sealing portion 3, and eventually, cracks occur.

Therefore, based on the above findings, it is understood that the shape of the step SP of the electrode sealing portion 3 should be made gentle. In order to reproduce such a shape in the manufacture of the discharge lamp 1, as shown in FIG. 4 (b), the inclined portion SP is provided on the side of the bead rod 3b1 in the electrode sealing portion 3 on the side of the bead tube 3a1.
By performing the chamfering 1, the outer shape of the step portion SP of the electrode sealing portion 3 after the completion of the glass forming becomes gentle. If the shape (angle θ ₁ ) of the step portion SP of the electrode sealing portion 3 is too small, the gap between the inside of the glass tube portion 2 of the discharge lamp 1 and the outside air can be reduced as shown in FIG. The actual sealing length E of the electrode sealing part 3 provided for the purpose of blocking the electrode sealing part 3 and the metal foil 3b2 is reduced, and the discharge lamp 1 is stored for a long time or
It is conceivable that outside air enters into the glass tube portion 2 during lighting, and there is a limit to reducing the angle θ ₁ of the step portion SP of the electrode sealing portion 3 (the limit is 20 degrees).

Then, the angle θ ₁ of the step portion SP of the electrode sealing portion 3 and the above crack were verified, and the angle θ ₁ of the step portion SP of the electrode sealing portion 3 effective for crack resistance was obtained.

The verification method is to continuously apply a power of 1.2 times the rated power of the discharge lamp 1 while applying a mechanical stress to the step SP of the electrode sealing portion 3 while the discharge lamp 1 is lit. A load test was performed. The used discharge lamp 1 is a short arc type discharge lamp, and its general specifications are as follows. Glass tube diameter: 82 mmφ Amount of mercury enclosed: 30 mg / cc
Rated power: 5 kW Discharge voltage: 50 V Discharge current: 10
0A

The operating life of the short arc type discharge lamp, which is the discharge lamp 1, is usually 750 to 1500 hours, and therefore, under the above-mentioned overload condition with respect to the angle θ ₁ of the step SP of the electrode sealing portion 3. FIG. 5 (a) shows the result of investigating the time until the occurrence of cracks in the electrode sealing portion 3 by lighting the discharge lamp 1 for up to 1500 hours. FIG.
As can be seen from (a), the upper limit value of the angle θ ₁ of the electrode sealing portion 3 that can withstand lighting for 1500 hours is 60 degrees, and the angle θ ₁ of the step portion SP of the electrode sealing portion 3 at an angle less than this. By setting the above, it is possible to provide the discharge lamp 1 having strong crack resistance in the step portion SP of the electrode sealing portion 3. Note that the lower limit of the angle θ ₁ of the step SP of the electrode sealing portion 3 is 20 degrees due to the above-described restriction on the length of the actual seal length E between the seal tube 4 of the electrode sealing portion 3 and the metal foil 3b2. It is.

The angle θ ₁ of the step SP of the electrode sealing section 3
Is determined by the welding method of the electrode sealing portion 3 of the discharge lamp 1 as described above. To make this easier,
It is effective to provide an inclined portion SP1 on the side surface of the bead rod 3b1 provided in the electrode sealing portion 3 on the side of the bead tube 3a1. The angle θ ₂ of the inclined portion SP1 of the bead rod 3b1 is
It can be said that the angle θ ₁ of the step SP of the electrode sealing portion 3 should be determined so as to be 60 degrees or less.

In the actual operation, the inclined part SP1 of the bead rod 3b1
FIG. 5 (b) shows the result of examining the relationship between the angle θ ₂ and the angle θ ₁ of the step SP of the electrode sealing portion 3. According to this, it is understood that the angle of the electrode sealing portion 3 can be reduced to 60 degrees or less by setting the angle θ ₂ of the inclined portion SP1 of the bead rod 3b2 to 45 degrees or less. Note that the lower limit of the angle θ ₂ of the inclined portion SP1 of the bead rod 3b1 is determined by the step S of the electrode sealing portion 3 described above.
Which is the lower limit of the angle theta ₁ of P is 20 degrees which is a value corresponding to 20 degrees.

As described above, the step SP of the electrode sealing portion 3
The angle θ ₁ is set to 60 degrees or less, and in order to easily realize the angle θ ₁ in the welding operation of the electrode sealing portion 3, an inclined portion of 45 degrees or less is provided on the side surface of the bead rod 3 b 1 on the side of the bead tube 3 a _1. By applying SP1, the crack resistance of the step portion SP of the electrode sealing portion 3 when the glass tube portion 2 is lit can be improved and stabilized.

As described above, the angle θ ₁ of the step SP of the electrode sealing portion 3 was set at 40 °, and the angle θ ₂ of the inclined portion SP1 of the bead rod 3b1 was set at 30 ° to realize this. When the above-mentioned overload test was performed on the discharge lamp 1 of 5 kW, cracks did not occur in the step portion SP of the electrode sealing portion 3 even after lighting for 3000 hours, and strong crack resistance was exhibited. The discharge lamp 1 used in this test is a short arc type discharge lamp, and the general specifications are the same as those used in the overload test. Glass tube diameter: 82 mmφ Amount of mercury enclosed: 30 mg / cc
Rated power: 5 kW Discharge voltage: 50 V Discharge current: 10
0A

In the embodiment of the present invention, the electrode sealing portion 3
The angle of intersection of the angle θ ₁ of the step SP with the axis is 20 degrees to 6 degrees.
Although the reason for setting the angle to 0 degrees has been described only for the anode side of the discharge lamp, it is needless to say that the cathode side is also set for the same reason. Further, the present invention is not limited to the above-described embodiment of the invention, and can be implemented with appropriate modifications as needed within a range in which the objects and effects of the present invention are produced.

[0030]

According to the present invention having the above configuration and operation, the following effects can be obtained. 1) According to the invention according to claim 1 of the present invention, the joint portion between the small diameter portion and the large diameter portion in the electrode sealing portion of the discharge lamp is made 20
Is formed so as to have a slope of from 60 degrees to 60 degrees, thereby providing a strong strength based on the relationship between the shape of the step portion of the electrode sealing portion of the discharge lamp and the occurrence of cracks during lighting of the discharge lamp starting from the step portion. It is possible to provide a discharge lamp having a shape of a step portion of an electrode sealing portion having excellent crack resistance. Therefore, the service life of the discharge lamp can be significantly extended. 2) According to the invention of claim 2 of the present invention, by using a member formed so that the angle between the electrode-side end face of the bead rod and the side face of the bead rod is 20 degrees to 45 degrees. In addition, the shape of the step portion of the electrode sealing portion having strong crack resistance can be easily formed.

[Brief description of the drawings]

FIG. 1 is an overall partial sectional view showing one embodiment of a discharge lamp according to the present invention.

FIG. 2 (a) is a cross-sectional view of the electrode sealing portion of the discharge lamp according to the present invention on the anode side. (B) It is an important section enlarged sectional view by the side of the anode of the electrode sealing part of the discharge lamp concerning the present invention.

FIG. 3 is a schematic diagram showing a temperature difference at a step portion of an electrode sealing portion of the discharge lamp according to the present invention.

FIG. 4A is a diagram showing a temperature gradient with respect to an angle of a step portion of an electrode sealing portion of a discharge lamp according to the present invention. (B) It is a figure for explaining the seal length of the electrode sealing part of the discharge lamp concerning the present invention.

FIG. 5 (a) is a diagram showing a time until a crack occurs in a step portion with respect to an angle of a step portion of an electrode sealing portion of a discharge lamp according to the present invention. (B) It is a figure which shows the angle of the inclination part of a bead rod with respect to the angle of the step part of the electrode sealing part of the discharge lamp which concerns on this invention.

FIG. 6 (a) is a vertical sectional view on the anode side of an electrode sealing portion of a conventional discharge lamp. (B) It is an enlarged view of the step part of the electrode sealing part of the conventional discharge lamp.

FIG. 7 is a view showing an angle of a step portion of an electrode sealing portion of a conventional discharge lamp. (A) It is a figure showing a gentle step shape. (B) is a diagram showing a steep step shape.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Glass tube part 3, 3 'Electrode sealing part 3a, 3'a Small diameter part 3a1, 3'a1 Bead tube 3b, 3'b Large diameter part 3b1, 3'b1 Bead rod 3b2, 3'b2 metal foils 4,4 'seal tube SP, SP' step portions SP1, the angle of inclination of the angle theta ₂ beads rod of the step portion of the inclined portion theta ₁ electrode sealing portion of the SP'1 beads rod

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akiyoshi Fujimori 3-34-1, Chofugaoka, Chofu-shi, Tokyo F-term in Oak Manufacturing Co., Ltd. 5C043 AA14 BB01 CC02 CD01 DD11 EA07 EC20

Claims (2)

[Claims] An electrode sealing portion is formed by continuously forming a glass tube portion having a diameter increasing from a small-diameter portion to a large-diameter portion at both ends of a glass tube bulb portion having a central bulge; In a discharge lamp provided with a cathode and an anode opposed to each other in a glass tube portion and emitting ultraviolet rays of a predetermined wavelength by arc discharge, the small-diameter portion supporting the electrode lead rods of the two electrodes via a bead tube, A joint portion with the large diameter portion for sealingly supporting the metal foil for supplying power to the both electrodes via a bead rod is 20
A discharge lamp characterized in that the discharge lamp is formed to have a slope of from 60 degrees to 60 degrees. 2. The discharge device according to claim 1, wherein an inclined portion formed between an end surface of the bead bar on the electrode side and a side surface of the bead bar is formed to have an angle of 20 to 45 degrees. Electric lights.