TWI431660B - Discharge lamp - Google Patents

Description

Discharge lamp

The present invention relates to a discharge lamp, and more particularly to a discharge lamp having a hermetic sealing configuration that is particularly suitable for high current applications.

In general, discharge lamps (for example, mercury lamps) have been widely used in the field of utilizing ultraviolet rays emitted from lamps, for example, in the field of photochemical industry, in the manufacture of semiconductor elements, and other fields.

In a high-pressure mercury lamp or an ultra-high-pressure mercury lamp for high-current use, the amount of mercury enclosed as a main component of the luminescent gas is large, and the gas pressure in the arc tube at the time of lighting is very high, and the amount of heat generation is large, and therefore, especially in the hermetic sealing portion. In the glass, heat resistance and pressure resistance must be large. Moreover, in the lighting, the mercury in the luminous tube must be completely evaporated, so that in the luminous tube in the lighting, there must be no lower temperature portion such as mercury condensation.

Therefore, in the conventional high-pressure mercury lamp or ultra-high pressure mercury lamp, a so-called rod seal which achieves a hermetic sealing of the sealing tube by directly welding the glass forming the sealing tube to the lead rod for power supply is not employed. The structure is a so-called foil sealing structure using a metal foil for sealing.

Fig. 7 is an explanatory view showing an example of a high pressure mercury lamp having a foil sealing structure. 1 is a discharge vessel composed of an arc tube 11 and a sealing tube 12 connected thereto. An electrode 2 is disposed in the arc tube 11 of the discharge vessel 1, and the electrode 2 is supported by an inner lead bar 3. The inner lead bar 3 is held in the sealing tube 12 by holding the glass holding cylinder 4 of the inner lead bar 3.

Then, the rear end side of the inner lead bar 3 opposite to the electrode 2 is inserted into a through hole of the current collector plate 5 made of a high melting point metal such as molybdenum, and is welded to the current collector plate 5 in the set. A metal foil 6 for power supply is welded to the surface of the electric plate 5 on the side of the arc tube 11. The metal foil 6 for electric power supply is attached to the outer periphery of the cylindrical glass member 7, and is spaced apart in the circumferential direction, and five, for example, five strips are arranged in the axial direction of the glass member 7.

Then, the power supply metal foil 6 is welded to the disk-shaped metal member 8 at the other end opposite to the direction in which the current collector plate 5 is welded, and is electrically connected to the external lead bar 9 through the metal member 8. .

The outer lead bar 9 is held by the glass holding cylinder 41 holding the outer lead bar 9 , is welded to the metal member 8 through the metal member 8 , and is inserted into the hole 71 formed in the glass member 7 .

Next, a metal foil M1 made of molybdenum is disposed between the glass member 7 and the current collector 5, and a metal foil M2 made of molybdenum is disposed between the holding cylinder 4 holding the inner lead bar 3 and the current collector 5.

As shown in Fig. 8(a), the metal foil M1 is a disk-shaped metal foil having no through holes, and its diameter is substantially the same as the diameter of the current collector plate 5.

As shown in Fig. 8(b), the metal foil M2 is an annular metal foil having a through hole through which the inner lead 3 is formed at the center, and has a diameter substantially the same as the diameter of the current collector 5.

However, since the other sealed pipe portion has the same structure, the description thereof will be omitted.

In the arc tube 11 of the discharge vessel 1 configured as described above, the electrode 2 is placed in an insertion manner. Then, the discharge vessel 1 is rotated in the circumferential direction by a glass disk or the like, and is heat-treated by a burner or the like from the outside of the sealing tube 12, and the inner circumference of the sealing tube 12 and the outer periphery of the glass member 7 are supplied with electricity. The metal foil 6 is used for hermetic welding.

Further, the glass of the sealing tube 12 at a portion facing the holding cylinder 4 is also heat-treated, and the inner circumference of the sealing tube 12 is welded to the holding cylinder 4.

However, since the other sealed pipe portion has the same structure, the description thereof will be omitted.

In the heat treatment process of the sealing tube 12, when the glass member 7 is in contact with the current collector 5, the expansion coefficient of the respective members may be different, and fine cracks may occur in the glass member 7, so that the glass member 7 and the set are used. The metal foil M1 is disposed between the glass member 7 and the current collector 5 so that the electric plate 5 does not contact each other.

Similarly, in the heat treatment process of the sealing tube 12, if the holding cylinder 4 holding the inner lead 3 is in contact with the current collector 5, the expansion coefficient of each member may be different, and the holding cylinder 4 may occur. In the case of fine cracks, the metal foil M2 is disposed between the holding cylinder 4 and the current collector 5 so that the holding cylinder 4 and the current collector 5 are not in contact with each other.

Among them, depending on the lamp, there is a lamp having a structure in which the metal foil M2 is not disposed between the holding cylinder 4 and the current collector plate 5.

However, even in the structure in which the metal foil M1 is disposed between the glass member 7 and the current collector 5, a burner or the like is used outside the sealing tube 12. In the heat treatment process, depending on the case, cracks may occur in the portion of the glass member 7 that is in contact with the metal foil M1, and the cracks may grow in the lighting, and finally the gas in the arc tube 11 may leak or be sealed. The situation in which the tube 12 is destroyed.

As shown in FIG. 9, the rear end side of the inner lead bar 3 opposite to the electrode 2 is inserted into the through hole of the current collector plate 5 to be welded to the current collector plate 5, but it is difficult to make the inner lead wire. The base end 3a on the rear end side of the rod 3 coincides with the end surface 5a of the current collector plate 5, and the base end 3a of the inner lead bar 3 protrudes more than the end surface 5a of the collector plate 5 and is welded.

In the case of the configuration as shown above, in the process of heat treatment using a burner or the like from the outside of the sealing tube 12, the base end 3a of the protruding inner lead bar 3 presses the metal foil M against the side of the glass member 7 And the glass member 7 of the pressed portion is cracked.

(Patent Document 1) Japanese Patent Laid-Open Publication No. 2000-149873

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for preventing cracking of a glass member disposed in a sealed tube, and at the end, preventing gas leakage of the light-emitting tube and preventing damage of the sealed tube, thereby obtaining long-term use. The life of the discharge lamp.

The discharge lamp of the first aspect of the invention is composed of a discharge vessel having a sealed tube connected to both ends of the arc tube, a columnar glass member disposed inside the sealed tube, and inside the sealed tube. a metal current collector plate on which the end faces of the glass members face each other on the light-emitting tube side; the front end extends toward the inside of the light-emitting tube, and an electrode is provided at a tip end thereof, and a rear end side opposite to the electrode is inserted in the front side An inner lead bar fixed to the current collector plate through a through hole in the center of the collector plate; and a glass holding cylinder for holding the inner lead bar disposed between the outer circumference of the inner lead bar and the inner circumference of the sealing tube And a metal foil for power supply extending along the outer circumference of the glass member, the one end portion is connected to the current collector plate, and the other end portion is electrically connected to the outer lead bar, and the inner lead rod is rear end side The base end is more protruded than the end surface of the current collector plate, and a metal body is disposed between the glass member and the current collector plate, and the metal system has a base end for inserting the inner lead bar When the gap length of the base end of the inner lead bar protruding from the end surface of the current collector plate is L1, the gap is formed in a direction in which the base end of the inner lead bar of the metal body protrudes. When the length is set to L2, it is L1 < L2.

The discharge lamp of claim 2 is the discharge lamp of claim 1, wherein the metal system is laminated with a plurality of annular metal foils having through holes formed in the center, and the through holes of the respective metal foils overlap. Further, a communication hole is formed, and the communication hole is formed in a space provided in the metal body.

The discharge lamp of claim 3 is the discharge lamp of the first aspect of the patent application, in particular, the metal foil is composed of a flat portion and a curved portion in which the periphery of the flat portion is bent in the direction of the current collector plate. A recess is formed in a surface of the flat portion of the metal foil on the inner lead bar side and an inner edge of the bent portion of the metal foil, and the recess is formed in a gap of the metal body.

According to the discharge lamp of the present invention of claim 1, the rear end side of the inner lead bar is welded to the through hole of the current collector plate, and the current collecting plate and the columnar glass member disposed inside the sealing tube are Since the metal body is disposed between the metal bodies, the glass member can be isolated from the current collector plate without being in contact with each other. In addition, the metal system has a gap for inserting the base end of the end side of the inner lead bar, and the base end of the inner lead bar is more prominent than the end face of the collector plate, if the inner lead bar is protruded more than the end face of the collector plate The protruding length of the base end is L1, and when the length in the direction in which the base end of the inner lead bar provided in the gap of the metal body protrudes is L2, L1 < L2, so that the burner is used outside the sealed tube. When the heat treatment is performed, even if the base end of the end side after the inner lead bar is formed to protrude from the end surface of the current collector plate, the base end of the inner lead bar does not come into contact with the glass member, and therefore There is a case where the base end of the inner lead bar presses the glass member, so that cracking of the glass member can be prevented, and finally, gas leakage of the arc tube can be prevented, and the sealing tube can be prevented from being damaged, and a long service life can be obtained.

Further, according to the discharge lamp of the second aspect of the invention, in the metal system, a plurality of annular metal foils having through holes formed in the center are laminated, and the through holes of the respective metal foils are overlapped to form a communication hole. The communication hole is formed as a space provided in the metal body, and the space is inserted into the base end of the inner lead bar which protrudes more than the end surface of the current collector plate, so that the connection hole can be reliably prevented, and the glass member can be reliably prevented Connect the base end of the inner lead bar.

Further, according to the discharge lamp of the invention of claim 3, the metal system is composed of a flat portion and a metal foil formed by a curved portion bent in a direction of the current collector plate around the flat portion, by the metal foil a recess is formed in a surface of the flat portion on the inner lead bar side and an inner edge of the bent portion of the metal foil, and the recess is formed in a gap provided in the metal body, and the recess is inserted into the end surface of the collector plate. The base end of the aforementioned inner lead bar is protruded, so that it can be a simple configuration while reliably preventing the glass member from abutting against the base end of the inner lead bar.

The discharge lamp of the present invention will be described using a schematic diagram.

Figure 1 is a cross-sectional view of a discharge lamp of the present invention.

1 is a discharge vessel composed of an arc tube 11 and a sealing tube 12 connected thereto. An electrode 2 is disposed in the arc tube 11 of the discharge vessel 1, and the electrode 2 is provided at the tip end of the inner lead bar 3 extending toward the inside of the arc tube 11 at the tip end.

The inner lead bar 3 is inserted into the sealing tube 12 while being inserted into the through hole of the glass holding cylinder 4 disposed between the outer circumference of the inner lead bar 3 and the inner circumference of the sealing tube 12.

The rear end side of the inner lead bar 3 opposite to the electrode 2 is inserted through a through hole formed in the center of the collector plate 5 made of a high melting point metal such as molybdenum, and is fixed to the current collector plate 5 by fusion welding. .

A cylindrical glass member 7 is disposed inside the sealed tube 11.

The collector plate 5 is disposed inside the sealing tube 12 and is disposed to face the end faces of the glass member 7 on the side of the arc tube 11 .

The surface of the glass member 7 facing the current collector plate 5 is planar.

One end side of the power supply metal foil 6 is welded to the surface of the current collecting plate 5 on the side of the arc tube 11 , and the power supply metal foil 6 extends in the axial direction along the outer circumference of the cylindrical glass member 7 , for example, in the glass. The members 7 are arranged in a strip shape in the circumferential direction, and the other side of the power supply metal foil 6 opposite to the direction in which the current collector plate 5 is welded is welded to the disk-shaped metal member 8 and transmitted through The metal member 8 is electrically connected to the outer lead bar 9.

However, one end side of the power supply metal foil 6 may be welded to the side surface of the current collector plate 5.

The outer lead bar 9 is held by the glass holding cylinder 41 holding the outer lead bar 9 , is welded to the metal member 8 through the metal member 8 , and is inserted into the hole 71 formed in the glass member 7 .

Next, a metal body M is disposed between the glass member 7 and the current collector 5, and a metal foil M2 made of molybdenum is disposed between the holding cylinder 4 holding the inner lead bar 3 and the current collector 5.

The metal body M is described in detail in the latter section.

As shown in Fig. 8(b), the metal foil M2 is an annular metal foil having a through hole through which the inner lead bar 3 is inserted at the center, and the diameter thereof is substantially the same as the diameter of the current collector plate 5.

However, since the other sealed pipe portion has the same structure, the description thereof will be omitted.

In the case of the lamp, the metal foil M2 is not disposed between the holding cylinder 4 and the current collector plate 5.

Next, the function of the metal body M will be described in detail.

Fig. 2 is an enlarged cross-sectional view showing only the glass member and the metal body and the current collector plate and the inner lead bar.

As shown in Fig. 2, a metal body M is disposed between the glass member 7 and the current collector 5, and the outer diameter of the metal body M and the current collector plate 5 and the diameter of the end surface of the glass member 7 on the collector plate 5 side. A substantially uniform outer diameter of 10 mm was formed in the center with a through hole P having an inner diameter of 5 mm larger than the outer diameter of the base end on the rear end side of the inner lead bar, and a metal foil made of molybdenum having a thickness of 0.05 mm.

Further, as shown in Fig. 2, it is difficult to make the end surface 5a of the current collector plate 5 coincide with the base end 3a of the inner lead bar 3, and the base end 3a of the inner lead bar 3 slightly protrudes from the end surface 5a of the current collector plate 5, if The protruding length of the base end 3a of the inner lead bar 3 protruding from the end surface 5a of the current collector plate 5 is L1, and L1 is 0.033 mm.

Further, the length in the direction in which the base end 3a of the inner lead bar 3 provided in the gap K of the metal body M protrudes is L2, and L2 is 0.05 mm. The length of the L2 is the thickness of one metal foil.

That is, when the protruding length of the base end 3a of the inner lead bar 3 which protrudes more than the end surface 5a of the electric board 5 is L1, the base end 3a of the inner lead bar 3 provided in the gap K of the metal body M is provided. When the length of the protruding direction is set to L2, the relationship of L1 < L2 is satisfied.

As a result, when the glass member 7 and the sealing tube 12 are welded by the outside of the sealing tube 12, the metal body M is disposed between the glass member 7 and the current collecting plate 5, thereby utilizing the metal. The body M completely isolates the glass member 7 from the collector plate 5 from contact, and even if the base end 3a of the inner lead bar 3 protrudes more than the end face 5a of the collector plate 5, the base end 3a of the protruding portion does not The glass member 7 is abutted against the glass member 7, so that cracking of the glass member 7 can be prevented, and finally, the gas of the arc tube can be prevented from leaking, and the sealing tube can be prevented from being damaged, and a long service life can be obtained.

In addition, the combination of the metal body M, the current collector plate 5, and the glass member 7 is, for example, the outer diameter of the metal body M and the current collector plate 5, and the diameter of the end surface of the glass member 7 on the current collector plate 5 side. The same effect was obtained by a combination of the same inner diameter of the through hole of the metal body M of 6 mm. In addition, for example, the outer diameter of the metal body M and the current collector plate 5 and the diameter of the end surface of the glass member 7 on the current collector plate 5 side are substantially the same as 30 mm, and the inner diameter of the through hole of the metal body M is 6 mm. The same effect is obtained.

Figure 3 is an enlarged cross-sectional view showing only the glass member and the metal body and the current collector plate and the inner lead bar shown in another embodiment of the discharge lamp of the present invention, and Fig. 4 is only the metal shown in Fig. 3 taken out. Oblique view of the metal foil of the body.

As shown in Fig. 3, a metal body M having an inner lead bar 3 protruding more than the end surface 5a of the current collector plate 5 is disposed between the glass member 7 and the current collector plate 5. The gap K into which the base end 3a is inserted.

The metal body M has a structure in which three annular metal foils Ma having through holes P are formed in the center as shown in Fig. 4 .

The current collector plate 5 is a molybdenum metal plate having a thickness of 2 mm and an outer diameter of 10 mm, and a through hole having an inner diameter of 5 mm through which the inner lead 3 communicates is formed at the center.

As shown in Fig. 4, the outer diameter of the metal foil Ma and the current collector plate 5 and the diameter of the end surface of the glass member 7 on the collector plate 5 side are substantially the same as the outer diameter of 10 mm and the inner diameter of the inner diameter of 5 mm is formed. A through-hole P, a metal foil made of molybdenum having a thickness of 0.015 mm.

As shown in FIG. 3, the through holes P of the metal body M of the three metal foils Ma are stacked to form a communication hole formed in the space K of the metal body M.

Further, as shown in Fig. 3, it is difficult to make the end surface 5a of the current collector plate 5 coincide with the base end 3a of the inner lead bar 3, and the base end 3a of the inner lead bar 3 slightly protrudes from the end surface 5a of the current collector plate 5, if The protruding length of the base end 3a of the inner lead bar 3 which protrudes more than the end surface 5a of the collector plate 5 is L1, and L1 is 0.033 mm.

Further, the length in the direction in which the base end 3a of the inner lead bar 3 provided in the gap K of the metal body M protrudes is L2, and L2 is 0.045 mm.

In the third drawing, for the sake of explanation, it is depicted that a gap is formed between the respective metal foils Ma, but there is actually no void, and the metal foil Ma is closely bonded, and the length of the L2 is three metal foils. The total thickness of Ma is equal.

That is, when the protruding length of the base end 3a of the inner lead bar 3 which is further protruded from the end surface 5a of the current collector 5 is L1, the base end 3a of the inner lead bar 3 provided in the gap K of the metal body M is provided. When the length of the protruding direction is set to L2, the relationship of L1 < L2 is satisfied.

As a result, when the glass member 7 and the sealing tube 12 are welded by the outside of the sealing tube 12, the metal body M is disposed between the glass member 7 and the current collecting plate 5, thereby utilizing the metal. The body M completely isolates the glass member 7 from the collector plate 5 from contact, and even if the base end 3a of the inner lead bar 3 protrudes more than the end face 5a of the collector plate 5, the base end of the base end 3a of the protruding portion 3a does not abut against the glass member 7, so that cracking of the glass member 7 can be prevented, and finally, gas leakage of the arc tube can be prevented, and the sealing tube can be prevented from being damaged, and a long service life can be obtained.

In the above embodiment, the metal body M has a structure in which three metal foils Ma having the through holes P are laminated, but the base of the inner lead bars 3 which protrudes more than the end surface 5a of the current collector plate 5 may be used. The length of the end 3a is appropriately changed by the number of layers of the metal foil Ma.

Fig. 5 is an enlarged cross-sectional view showing only the glass member and the metal body, and the current collector plate and the inner lead bar when the metal body of the other embodiment is used.

In Fig. 5, the length L1 of the base end 3a of the inner lead bar 3 which is more protruded than the end face 5a of the collector plate 5 is provided at the base end of the inner lead bar 3 of the gap K of the metal body M. The length L2 of the direction in which the protrusion 3a is long is a long structure, and the disc-shaped metal foil M1 having no through hole shown in Fig. 8(a) is disposed in the metal foil Ma to be laminated, which is closest to the collector plate. 5 of the metal foil Ma of the collector plate 5 side.

In the discharge lamp as described above, when the sealing tube is subjected to heat treatment, the metal foil M1 having no through hole is deformed so as to enter the gap K by the base end 3a of the inner lead bar 3.

However, since L1 < L2, even if the metal foil M1 having no through hole is deformed, the base end 3a of the inner lead bar 3 and the glass member 7 are not surely in contact with each other, and cracking of the glass member 7 can be prevented. .

However, although not shown, even if the disk-shaped metal foil M1 which does not have a through-hole as shown in FIG. 8 (a) is arrange|positioned between the metal foil Ma shown by FIG. 3, the sealing tube is heated. During the treatment, the metal foil M1 having no through-holes is deformed by the base end 3a of the inner lead bar 3 so as to enter the gap K, but the total thickness of the metal body Ma (at this time, if the metal body Ma is all In the case of close contact, the length L2 in the direction in which the base end 3a of the inner lead bar 3 provided in the gap K of the metal body Ma protrudes is the same) L2 is larger than the inner side of the end face 5a of the collector plate 5 The length L1 of the base end 3a of the lead bar 3 is formed such that the base end 3a of the inner lead bar 3 does not reliably contact the glass member 7, and cracking of the glass member 7 can be prevented.

Figure 6 is an enlarged cross-sectional view showing only the glass member and the metal body and the current collector plate and the inner lead bar of the other embodiment of the discharge lamp of the present invention.

As shown in Fig. 6, a metal body M is disposed between the glass member 7 and the current collector 5, and the metal system has a structure in which the periphery of one metal foil Mb is bent.

The current collector plate 5 is a metal plate made of molybdenum, and has a thickness of 2 mm and an outer diameter of 10 mm, and a through hole having an inner diameter of 5 mm through which the inner lead bars 3 communicate with each other is formed at the center.

The end surface of the glass member 7 on the collector plate 5 side has a diameter of 10 mm.

The metal foil Mb is composed of a flat portion Mb1 and a curved portion Mb2 bent in the direction of the current collector plate around the flat portion Mb1, and the surface Mb10 and the curved portion Mb2 on the inner lead bar 3 side in the flat portion Mb1 The inner edge Mb20 forms a recess K2 into which the base end 3a of the inner lead bar 3 which protrudes more than the end surface 5a of the collector plate 5 is inserted.

The metal foil Mb has a thickness of 0.10 mm, an outer diameter of 10 mm, and an opening diameter of the inner edge Mb20 of the curved portion Mb2 of 7 mm.

Further, as shown in Fig. 6, when the protruding length of the base end 3a of the inner lead bar 3 which protrudes more than the end surface 5a of the current collector plate 5 is L1, L1 is 0.033 mm.

In addition, the length in the direction in which the base end 3a of the inner lead bar 3 of the metal body M belonging to the recess K2 of the gap K protrudes is L2, and L2 is 0.045 mm. In the embodiment, the length of L2 is the length from the surface Mb10 of the flat portion Mb1 and the front end portion of the inner edge Mb20 of the curved portion Mb2 on the collector plate 5 side.

That is, when the protruding length of the base end 3a of the inner lead bar 3 which is further protruded from the end surface 5a of the current collector 5 is L1, the base end 3a of the inner lead bar 3 provided in the gap K of the metal body M is provided. When the length of the protruding direction is set to L2, the relationship of L1 < L2 is satisfied.

As a result, even if the base end 3a of the inner lead bar 3 protrudes more than the end face 5a of the collector plate 5, the portion where the base end 3a protrudes is inserted into the recess K2 of the metal foil Mb, and is formed as the base of the inner lead bar 3. The end 3a does not abut the state of the glass member 7.

As a result, when the glass member 7 and the sealing tube 12 are welded by the outside of the sealing tube 12, the metal body M is disposed between the glass member 7 and the current collecting plate 5, thereby utilizing the metal. The body M completely isolates the glass member 7 from the collector plate 5 from contact, and even if the base end 3a of the inner lead bar 3 protrudes more than the end face 5a of the collector plate 5, the base end of the base end 3a of the protruding portion 3a does not abut against the glass member 7, so that cracking of the glass member 7 can be prevented, and finally, gas leakage of the arc tube can be prevented, and the sealing tube can be prevented from being damaged, and a long service life can be obtained.

1. . . Discharge capacitor

2. . . electrode

3. . . Internal lead bar

3a. . . Base end of inner lead rod 3

4. . . Holding cylinder

5. . . Collector board

5a. . . End face of collector plate 5

6. . . Metal foil for power supply

7. . . Glass member

8. . . Metal component

9. . . External lead bar

11. . . Luminous tube

12. . . Sealing tube

41. . . Holding cylinder

71. . . hole

K. . . Void

K2. . . Concave

L1‧‧‧ length

L2‧‧‧ length

M‧‧‧ metal body

M1‧‧‧metal foil

M2‧‧‧metal foil

Ma‧‧‧metal foil

Mb1‧‧‧ Flat Department

Mb2‧‧‧Bend

Mb10‧‧‧ Surface of the inner lead bar 3 side in the flat portion Mb1

Mb20‧‧‧The inner edge of the curved part Mb2

P‧‧‧through holes

Fig. 1 is an explanatory view of a discharge lamp of the present invention.

Fig. 2 is an enlarged cross-sectional view showing only the glass member and the metal body of the discharge lamp of the present invention, and the current collector plate and the inner lead bar.

Fig. 3 is an enlarged cross-sectional view showing only the glass member and the metal body of the discharge lamp of the present invention, and the current collector plate and the inner lead bar.

Fig. 4 is a perspective view showing only the metal foil constituting the metal body shown in Fig. 3 taken out.

Fig. 5 is an enlarged cross-sectional view showing only the glass member and the metal body of the discharge lamp of the present invention, and the current collector plate and the inner lead bar.

Figure 6 is an enlarged cross-sectional view showing only the glass member and the metal body and the current collector plate and the inner lead bar of the other embodiment of the discharge lamp of the present invention.

Fig. 7 is an explanatory view of a conventional discharge lamp.

Fig. 8 is a perspective view showing only the metal foil of the discharge lamp shown in Fig. 7 taken out.

Fig. 9 is an explanatory view showing a fixing structure of the current collector plate and the inner lead.

3. . . Internal lead bar

3a. . . Base end of inner lead rod 3

5. . . Collector board

5a. . . End face of collector plate 5

7. . . Glass member

K. . . Void

L1. . . length

L2. . . length

M. . . Metal body

P. . . Through hole

Claims (3)

A discharge lamp comprising: a discharge vessel having a seal tube connected to both ends of the arc tube; a columnar glass member disposed inside the seal tube; and a light emitting member of the glass member inside the seal tube a metal collector plate having opposite end faces of the tube side; the front end extends toward the inside of the arc tube, and an electrode is provided at a front end thereof, and a rear end side opposite to the electrode is inserted at a center formed at the center of the current collector plate An inner lead bar fixed to the current collector plate through the through hole; a glass holding cylinder for holding the inner lead bar disposed between the outer circumference of the inner lead bar and the inner circumference of the sealing tube; and along a metal foil for supplying power to the outer periphery of the glass member, wherein one end portion is connected to the current collector plate and the other end portion is electrically connected to the outer lead bar, and the base end of the inner lead bar is rear end side The end surface of the current collector plate is more protruded, and a metal body is disposed between the glass member and the current collector plate, and the metal system has a space for inserting a base end of the inner lead bar. The protruding length of the base end of the inner lead bar in which the end surface of the current collector plate is more protruded is L1, and when the length in the direction in which the base end of the inner lead bar provided in the gap of the metal body protrudes is L2, Is L1 < L2. The discharge lamp of the first aspect of the invention, wherein the metal system has a plurality of annular metal foils having a through hole formed in a center thereof, wherein the through holes of the respective metal foils are overlapped to form a communication hole, and the communication is formed. The holes are formed as voids provided in the aforementioned metal body. The discharge lamp of the first aspect of the invention, wherein the metal foil is formed of a flat portion and a curved portion bent in a direction of the current collector plate around the flat portion, and the metal foil is flattened by the metal foil A recess is formed in a surface of the inner lead bar side of the portion and an inner edge of the bent portion of the metal foil, and the recess is formed in a gap provided in the metal body.