JP6153062B2 - Discharge lamp and discharge lamp manufacturing method - Google Patents

Description

Embodiments described below generally relate to a discharge lamp and a method for manufacturing a discharge lamp .

A light emitting part having a discharge space inside, a sealing part provided at an end part of the light emitting part, an electrode provided at one end inside the discharge space and the other end provided inside the sealing part; There is a discharge lamp that is provided inside a stop and has a metal foil joined to an electrode.
In such a discharge lamp, the metal foil peels off from the sealing part, so that a crack may occur in the sealing part. If a crack occurs in the sealing portion, a so-called foil leak may occur in which a metal halide or the like enclosed in the discharge space leaks through the crack. And if foil leak arises, it will lead to a non-light, and there exists a problem that the lifetime of a discharge lamp becomes short.
Therefore, a technique has been proposed in which a plurality of recesses are provided on the main surface of the metal foil to suppress the occurrence of foil leak.
However, in recent years, it has been desired to further extend the life of the discharge lamp.

Japanese Patent No. 4681668

The problem to be solved by the present invention is to provide a discharge lamp and a method for manufacturing the discharge lamp that can extend the life.

The discharge lamp according to the embodiment includes: a light emitting unit having a discharge space therein; a sealing unit provided at an end of the light emitting unit; one end provided inside the discharge space, and the other end sealed An electrode provided inside the part; and a metal foil provided inside the sealing part, joined to the electrode, and having a plurality of recesses on the main surface. A plurality of inclined surfaces with different inclination angles are provided on the side walls of the plurality of recesses, and the opening portions of the plurality of recesses in the thickness direction of the metal foil are surfaces of the metal foil. The outer edges of the adjacent recesses are in contact with each other in the plan view, or the outer edges of the adjacent recesses are separated from each other .

According to the embodiments of the present invention, it is possible to provide a discharge lamp and a method for manufacturing the discharge lamp that can extend the life.

It is a schematic diagram for illustrating the discharge lamp 100 according to the present embodiment. 4 is a schematic diagram for illustrating a plurality of recesses 41 provided on a surface 31a of a metal foil 31. FIG. (A)-(d) is a schematic plan view for illustrating the arrangement | positioning form of the recessed part 41. FIG. 4 is a schematic cross-sectional view for illustrating the cross-sectional shape of a recess 41. FIG. It is a graph for demonstrating about the effect which provides the some inclined surface from which an inclination angle differs mutually. (A), (b) is a schematic diagram for illustrating about the formation method of the some inclined surface from which an inclination angle mutually differs.

A first invention includes: a light emitting portion having a discharge space therein; a sealing portion provided at an end of the light emitting portion; one end provided in the discharge space, and the other end of the sealing portion A discharge lamp comprising: an electrode provided inside; and a metal foil provided inside the sealing portion, joined to the electrode, and having a plurality of recesses on a main surface.
A plurality of inclined surfaces with different inclination angles are provided on the side walls of the plurality of recesses, and the opening portions of the plurality of recesses in the thickness direction of the metal foil are surfaces of the metal foil. The outer edges of the adjacent recesses are in contact with each other in the plan view, or the outer edges of the adjacent recesses are separated from each other .
According to this discharge lamp, the life of the discharge lamp can be extended.

The second invention is the first invention, the dimensions of the cross section perpendicular to the central axis in each of the opening portions of the plurality of recesses, the center of each of the plurality of inclined surfaces connecting portion between of said plurality of recesses The discharge lamp is longer than the dimension of the cross section perpendicular to the axis.
According to this discharge lamp, the life of the discharge lamp can be extended.

A third invention is the discharge lamp according to the first or second invention, wherein the plurality of recesses are not provided in a region where the electrode of the metal foil is joined.
According to this discharge lamp, it is possible to suppress a decrease in the bonding strength between the metal foil and the electrode.

A fourth invention is a method for manufacturing the above-described discharge lamp, wherein a plurality of laser beams having different beam shapes are sequentially irradiated to predetermined positions on the main surface of the metal foil, so that a plurality of the main surfaces of the metal foil are provided. Forming a plurality of recesses, and in the step of forming the plurality of recesses, a plurality of inclined surfaces having different inclination angles are formed on each side wall of the plurality of recesses, and the thickness direction of the metal foil And the respective opening portions of the plurality of recesses are provided at positions on the surface of the metal foil, and the outer edges of the adjacent recesses are in contact with each other in plan view, or the outer edges of the adjacent recesses are in contact with each other. Is a method of manufacturing a discharge lamp formed so as to be separated from each other .

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
The discharge lamp according to the embodiment of the present invention can be, for example, an HID (High Intensity Discharge) lamp used for an automobile headlamp. Moreover, when it is set as the HID lamp used for the headlamp of a motor vehicle, what is called horizontal lighting can be performed.

  Although the use of the discharge lamp according to the embodiment of the present invention is not limited to a vehicle headlamp, here, as an example, a case where the discharge lamp is an HID lamp used for a vehicle headlamp is an example. Will be described.

FIG. 1 is a schematic diagram for illustrating a discharge lamp 100 according to the present embodiment.
In FIG. 1, when the discharge lamp 100 is attached to the automobile, the front direction is the front end side, the opposite direction is the rear end side, the upper direction is the upper end side, and the lower direction is the lower end side. Yes.
As shown in FIG. 1, the discharge lamp 100 is provided with a burner 101 and a socket 102.

The burner 101 is provided with an inner tube 1, an outer tube 5, a light emitting unit 11, a sealing unit 12, an electrode mount 3, a support wire 35, a sleeve 4, and a metal band 71.
The inner tube 1 has a cylindrical shape and is formed of a material having translucency and heat resistance. The inner tube 1 can be formed from, for example, quartz glass.
The outer tube 5 is provided outside the inner tube 1 and concentric with the inner tube 1. That is, it has a double tube structure.

  The outer tube 5 and the inner tube 1 can be connected by welding the outer tube 5 near the cylindrical portion 14 of the inner tube 1. Gas is enclosed in a closed space formed between the inner tube 1 and the outer tube 5. The gas to be filled can be a gas capable of dielectric barrier discharge, for example, a kind of gas selected from neon, argon, xenon, nitrogen, or a mixed gas thereof. The gas sealing pressure can be, for example, 0.3 atm or less at room temperature (25 ° C.), and more preferably 0.1 atm or less.

The outer tube 5 is preferably formed of a material that has a thermal expansion coefficient close to that of the material of the inner tube 1 and has an ultraviolet blocking property. The outer tube 5 can be formed, for example, from quartz glass to which an oxide such as titanium, cerium, or aluminum is added.
The light emitting unit 11 has a substantially elliptical cross-sectional shape and is provided near the center of the inner tube 1. Inside the light emitting unit 11, a discharge space 111 having a substantially cylindrical shape at the center and tapered at both ends is provided.

A discharge medium is enclosed in the discharge space 111. The discharge medium includes a metal halide 2 and an inert gas.
The metal halide 2 may include, for example, indium halide, sodium halide, scandium halide, zinc halide, and the like. As the halogen, for example, iodine can be exemplified. However, bromine or chlorine can be used instead of iodine.
Note that the composition of the metal halide 2 is not limited to that illustrated, but can be changed as appropriate.

  The inert gas sealed in the discharge space 111 can be xenon, for example. The inert gas can adjust the sealing pressure according to the purpose. For example, in order to increase the total luminous flux, it is preferable that the sealing pressure is 10 atm or more and 20 atm or less at room temperature (25 ° C.). In addition to xenon, neon, argon, krypton, or the like, or a mixed gas in which these are combined can also be used.

The sealing portion 12 has a plate shape and is provided at both ends of the light emitting portion 11 in the direction in which the pair of electrodes 32 extends.
The sealing portion 12 can be formed using, for example, a pinch seal method. Note that the sealing portion 12 may be formed by a shrink seal method and may have a cylindrical shape.
A cylindrical portion 14 is continuously formed at the end of one sealing portion 12 opposite to the light emitting portion 11 side via a boundary portion 13.

The electrode mount 3 is provided inside the sealing portion 12.
The electrode mount 3 is provided with a metal foil 31, an electrode 32, a coil 33, and a lead wire 34.
The metal foil 31 has a thin plate shape and can be formed of, for example, molybdenum, rhenium molybdenum, tungsten, rhenium tungsten, or the like.
The metal foil 31 may have a single layer structure or a multilayer structure.
A plurality of recesses 41 are provided on the surface 31a and the surface 31b, which are the main surfaces of the metal foil 31, respectively.
Details regarding the recess 41 will be described later.

  The electrode 32 has a linear shape with a circular cross section, and is formed of, for example, a so-called triated tungsten in which tungsten is doped with thorium oxide. The material of the electrode 32 may be pure tungsten, doped tungsten, rhenium tungsten, or the like. One end of the electrode 32 is welded to the vicinity of the end of the metal foil 31 on the light emitting unit 11 side. The welding of the electrode 32 and the metal foil 31 can be performed by laser welding.

The other end of the electrode 32 protrudes into the discharge space 111. The pair of electrodes 32 are arranged so that the tips thereof are opposed to each other while maintaining a predetermined distance.
In other words, the pair of electrodes 32 protrude into the discharge space 111 and are arranged to face each other at a predetermined distance.
The distance between the tips of the electrodes 32 can be, for example, 3.4 mm or more and 4.4 mm or less.

The diameter dimension of the electrode 32 can be 0.2 mm or more and 0.4 mm or less.
When the diameter dimension of the electrode 32 is less than 0.2 mm, the temperature of the electrode 32 becomes too high at the time of lighting, and the scattering (sputtering) of the electrode material into the discharge space 111 may increase. When the scattering of the electrode material into the discharge space 111 increases, the luminous flux maintenance factor during lighting decreases and the lifetime is shortened.
When the diameter dimension of the electrode 32 exceeds 0.4 mm, the distortion in the sealing portion 12 may increase. When the distortion in the sealing portion 12 increases, cracks or the like may occur in the sealing portion 12 when the discharge lamp 100 is manufactured or turned on.

  The diameter dimension of the electrode 32 may not be constant in the direction in which the electrode 32 extends. For example, the diameter dimension of the electrode 32 may be longer on the distal end side than on the proximal end side. Further, the tip of the electrode 32 may be spherical. Moreover, the diameter dimension of one electrode may differ from the diameter dimension of the other electrode like a direct current lighting type.

  The coil 33 can be formed from, for example, a metal wire made of doped tungsten. The coil 33 is wound around the outside of the electrode 32 provided inside the sealing portion 12. In this case, for example, the coil 33 can have a wire diameter of about 30 μm to 100 μm and a coil pitch of 600% or less.

  The lead wire 34 has a circular cross section and is made of molybdenum or the like. One end side of the lead wire 34 is welded to the vicinity of the end portion of the metal foil 31 opposite to the light emitting portion 11 side. The lead wire 34 and the metal foil 31 can be welded by laser welding. The other end side of the lead wire 34 extends to the outside of the inner tube 1.

The support wire 35 has an L shape and is welded to the end portion of the lead wire 34 extending from the front end side of the discharge lamp 100. The support wire 35 and the lead wire 34 can be welded by laser welding. The support wire 35 can be formed from nickel, for example.
The sleeve 4 covers a portion of the support wire 35 that extends in parallel with the inner tube 1. The sleeve 4 has, for example, a cylindrical shape and can be made of ceramic.
The metal band 71 is fixed to the outer peripheral surface on the rear end side of the outer tube 5.

The socket 102 is provided with a main body 6, a mounting bracket 72, a bottom terminal 81, and a side terminal 82.
The main body 6 is made of an insulating material such as resin. Inside the main body 6, a lead wire 34, a support wire 35, and a rear end side of the sleeve 4 are provided.

  The mounting bracket 72 is provided at the end of the main body 6 on the front end side. The mounting bracket 72 protrudes from the main body 6 and holds the metal band 71. The burner 101 is held by the socket 102 by holding the metal band 71 by the mounting bracket 72.

The bottom terminal 81 is provided inside the main body 6 on the rear end side. The bottom terminal 81 is made of a conductive material and is electrically connected to the lead wire 34.
The side terminal 82 is provided on the side wall on the rear end side of the main body 6. The side terminal 82 is made of a conductive material and is electrically connected to the support wire 35.

  And it connects with the lighting circuit which is not shown in figure so that the bottom terminal 81 may become a high voltage | pressure side and the side terminal 82 may become a low voltage | pressure side. In the case of an automobile headlamp, the discharge lamp 100 is mounted so that the central axis thereof is substantially horizontal and the support wire 35 is positioned on the lower end side (downward). And lighting up the discharge lamp 100 attached in such a direction is called horizontal lighting.

Next, the several recessed part 41 provided in the surface 31a and the surface 31b of the metal foil 31 is further illustrated.
FIG. 2 is a schematic diagram for illustrating the plurality of recesses 41 provided on the surface 31 a of the metal foil 31.
The same applies to the plurality of recesses 41 provided on the surface 31b of the metal foil 31. As shown in FIG. 2, a plurality of recesses 41 are provided on the surface 31 a and the surface 31 b of the metal foil 31.
In the region 31c where the electrodes 32 of the surface 31a and the surface 31b are joined, the concave portion 41 is not provided. For example, since the electrode 32 is laser-welded in the region 31c, the bonding strength (welding strength) may be reduced if the recess 41 is provided.
For this reason, the concave portion 41 is not provided in the region 31c.
The region 31c is also provided on the surface 31b.

The plurality of recesses 41 are provided in regions other than the region 31c of the surface 31a and the surface 31b.
In this case, a plurality of recesses 41 can be provided in the entire region other than the region 31c of the surface 31a and the surface 31b, or a plurality of recesses 41 can be provided in some regions.
In the specific example shown in FIG. 2, the recess 41 is not provided in a portion near the edge (end portion) of the metal foil 31. When the thickness of the edge of the metal foil 31 is thin, if the recess 41 is provided, the metal foil 31 may be penetrated. On the other hand, as shown in FIG. 2, by not providing the concave portion 41 in the portion near the edge of the metal foil 31, the penetration of the concave portion 41 can be prevented.
According to the knowledge obtained by the present inventors, the length of the surface 31a and the surface 31b in the direction in which the electrode 32 extends is L1, and the length in the direction in which the electrode 32 in the region where the plurality of recesses 41 are provided is L2. In addition, if L2 is set to L1 / 2 or more, the adhesion between the metal foil 31 and the sealing portion 12 can be improved, so that the metal foil 31 can be prevented from peeling off from the sealing portion 12.

That is, if the plurality of concave portions 41 are provided in a region that is approximately half or more of the surface 31a and the surface 31b, the metal foil 31 can be prevented from being peeled off from the sealing portion 12.
When a plurality of recesses 41 are provided in a part of the region, as illustrated in FIG. 2, the surface 31 a and the surface 31 b on the side where the electrodes 32 are joined (the side close to the discharge space 111). It is preferable to provide a plurality of recesses 41.
If a plurality of recesses 41 are provided in a part of the region, the number of processing of the recesses 41 can be reduced, so that the manufacturing cost can be reduced.
However, you may make it provide the some recessed part 41 in the whole surface 31a and the surface 31b. If it does so, although manufacturing cost will become high, the adhesiveness of the metal foil 31 and the sealing part 12 will become higher.

Further, the plurality of recesses 41 are provided so as not to overlap each other.
For example, the outer edges of the adjacent recesses 41 can be made to be in contact with each other substantially continuously in plan view.
Note that the outer edges of the adjacent recesses 41 are substantially continuously in contact with each other, not only when the outer edges of the adjacent recesses 41 are completely in contact with each other, but also with the outer edges of the adjacent recesses 41 being in proximity. This includes cases where

If the outer edges of the adjacent concave portions 41 are in contact with each other substantially continuously, the unprocessed regions (regions where the concave portions 41 are not formed) on the surfaces 31a and 31b are reduced.
Therefore, since the contact area between the metal foil 31 and the sealing part 12 can be increased, the adhesion between the metal foil 31 and the sealing part 12 can be enhanced. Further, it is possible to suppress the metal halide 2 sealed in the discharge space 111 from diffusing between the metal foil 31 and the sealing portion 12.

Here, if the adjacent recessed parts 41 have overlapped, the total surface area of the several recessed part 41 will become small, and adhesiveness with the sealing part 12 will fall.
In this case, in a state where more than half of the area of the recess 41 overlaps in plan view, the decrease in the adhesion with the sealing portion 12 increases due to the decrease in the total surface area of the plurality of recesses 41.

However, as long as the outer edges of the adjacent concave portions 41 are somewhat overlapped in plan view, the adhesion with the sealing portion 12 is slightly reduced due to a decrease in the total surface area of the plurality of concave portions 41, but the allowable range. Become.
Therefore, in this specification, “so as not to overlap each other” includes not only the case where the adjacent recesses 41 do not completely overlap, but also the case where the adjacent recesses 41 slightly overlap each other.

FIGS. 3A to 3D are schematic plan views for illustrating the arrangement of the recesses 41.
As shown in FIG. 3A, in the first direction X, the outer edges of the adjacent recesses 41 are substantially in contact with each other, and in the second direction Y perpendicular to the first direction X, they are adjacent. It can be set as the arrangement | positioning form which the outer edges of the recessed part 41 to contact do not contact.

In this case, in the second direction Y, an unprocessed region exists between the outer edges of the adjacent recesses 41. If the area of the unprocessed region becomes too large, the adhesiveness between the metal foil 31 and the sealing portion 12 is lowered, so that foil leakage is likely to occur. Therefore, there is a possibility that the life of the discharge lamp 100 cannot be extended.
Therefore, when the outer edge dimension (opening dimension) of the recess 41 is D1 and the pitch dimension of the recess 41 in the second direction Y is Py, it is preferable that D1 <Py ≦ 200 μm. With such a dimensional relationship, the occurrence of foil leak can be suppressed, so that the life of the discharge lamp 100 can be extended.

As shown in FIG. 3B, in the first direction X and the second direction Y, it is possible to adopt an arrangement form in which the outer edges of the adjacent recesses 41 are substantially in contact with each other.
With such an arrangement, the area of the unprocessed region can be reduced. Moreover, the processing number of the recessed part 41 can be increased. Therefore, the occurrence of foil leak can be further suppressed, and the life of the discharge lamp 100 can be further extended.

As shown in FIG. 3 (c), an arrangement configuration in which the plurality of concave portions 41 are closest packed (an arrangement configuration in which the number of processed concave portions 41 per unit area is the largest), that is, an outer edge of one concave portion 41. It is also possible to adopt a configuration in which the outer edges of the most other recesses 41 are in contact with each other.
With such an arrangement, the area of the unprocessed region can be further reduced. Moreover, the processing number of the recessed part 41 can further be increased. Therefore, the occurrence of foil leak can be further suppressed, so that the life of the discharge lamp 100 can be further extended.

As shown in FIG.3 (d), it can also be set as the arrangement | positioning form which the outer edges of the adjacent recessed part 41 do not contact in the 1st direction X and the 2nd direction Y. FIG.
In this case, an unprocessed region exists around the outer edge of the recess 41. If the area of the unprocessed region becomes too large, foil leakage is likely to occur.
Therefore, when it is set as such an arrangement | positioning form, it is preferable to shorten the dimension between adjacent recessed parts 41 as much as possible.

Moreover, as illustrated in FIGS. 3A to 3D, the arrangement of the plurality of recesses 41 can be made almost regular. That is, the arrangement of the plurality of recesses 41 can have a certain regularity.
If the arrangement of the plurality of recesses 41 is regular, it is possible to improve the reproducibility and reliability of the action effect as compared to the case where the plurality of recesses 41 are randomly arranged.
In addition, as long as the effect of providing the recessed part 41 does not become remarkably low, an error or a part which is intentionally not regular may exist.

  Further, the outer edge shape of the recess 41 illustrated in FIGS. 3A to 3D is circular, but in addition to a perfect circle and an ellipse, some of the contours are linear but most of the contours are circular or It may be an ellipse.

Next, the cross-sectional shape of the recess 41 will be illustrated.
FIG. 4 is a schematic cross-sectional view for illustrating the cross-sectional shape of the recess 41.
4 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 4, the recess 41 has a shape in which the area of the cross section perpendicular to the central axis 41 c of the recess 41 gradually decreases from the main surface (surface 31 a, surface 31 b) of the metal foil 31 toward the inside of the metal foil 31. have.

A plurality of inclined surfaces having different inclination angles are provided on the side wall of the recess 41. For example, an inclined surface 41 a having an inclination angle θa and an inclined surface 41 b having an inclination angle θb larger than the inclination angle θa are provided on the side wall of the recess 41. Further, the inclined surface 41a and the inclined surface 41b are formed continuously.
The inclination angle is an angle formed by the central axis 41c of the recess 41 and the inclined surface.
Further, the inclined surfaces 41a and 41b may be curved surfaces, flat surfaces, or may include curved surfaces and flat surfaces.

In addition, the dimension D1 of the cross section perpendicular to the central axis 41c in the opening portion of the concave portion 41 is longer than the dimension D2 of the cross section perpendicular to the central axis 41c in the connection portion between the inclined surface 41a and the inclined surface 41b of the concave portion 41. Yes.
Moreover, what is illustrated in FIG. 4 is a case where two inclined surfaces with different inclination angles are provided, but three or more side wall surfaces with different inclination angles may be provided.

Further, the inclination angle becomes larger as the inclined surface is closer to the main surface of the metal foil 31.
Moreover, the dimension of the cross section perpendicular | vertical to the central axis 41c is so long that it is the connection part of the inclined surfaces near the main surface of the metal foil 31. FIG.

  If a plurality of inclined surfaces having different inclination angles are provided on the side wall of the recess 41, the contact area between the metal foil 31 and the sealing portion 12 can be increased. Therefore, since the adhesiveness between the metal foil 31 and the sealing part 12 can be enhanced, the occurrence of foil leak can be further suppressed. As a result, the life of the discharge lamp 100 can be further extended.

Moreover, as shown in FIG. 4, the central axis 41c of the recessed part 41 provided in the surface 31a side and the central axis 41c of the recessed part 41 provided in the surface 31b side can mutually be shifted | deviated. If the central axes 41c of the recesses 41 are shifted from each other, the recesses 41 provided on the surface 31a side and the recesses 41 provided on the surface 31b side are not easily connected. Therefore, it can suppress that the intensity | strength of the metal foil 31 becomes weak.
In addition, if the dimension (shift | offset | difference dimension) between the central axis 41c of the recessed part 41 provided in the surface 31a side and the central axis 41c of the recessed part 41 provided in the surface 31b side is set to D1 / 2, the depth of the recessed part 41 will be described. Since the dimension can be further increased, the contact area between the metal foil 31 and the sealing portion 12 can be further increased.

FIG. 5 is a graph for illustrating the effect of providing a plurality of inclined surfaces having different inclination angles.
The vertical axis in FIG. 5 is the remaining rate (%) of the discharge lamp 100. That is, the number of discharge lamps 100 that have not been turned off / the total number of discharge lamps 100 that have been tested × 100 (%).

Moreover, 201 in FIG. 5 is the case of the recessed part which concerns on the comparative example which has one inclined surface.
202 is the case of the recessed part 41 which has two inclined surfaces from which an inclination angle differs mutually.
203 is the case of the recessed part 41 which has three inclined surfaces from which an inclination angle mutually differs.

  As can be seen from FIG. 5, if a plurality of inclined surfaces having different inclination angles are provided, the time required to reach the same remaining rate can be greatly extended. This means that the life of the discharge lamp 100 can be extended.

Next, a method for forming a plurality of inclined surfaces having different inclination angles will be described.
6A and 6B are schematic views for illustrating a method of forming a plurality of inclined surfaces having different inclination angles.
First, as shown to Fig.6 (a), the laser beam La is irradiated to the desired position of the surface 31a or the surface 31b of the metal foil 31, and the inclined surface 41a is formed.
At this time, the beam shape of the laser light is controlled so that the inclined surface 41a having the inclination angle θa is formed.
The beam shape of the laser beam can be changed by controlling the aperture of the laser beam, the distance between the laser beam irradiation device and the surface 31a or the surface 31b, the current value in the laser beam irradiation device, and the like.

Next, as shown in FIG. 6B, the laser beam Lb is irradiated to the position irradiated with the laser beam La to form an inclined surface 41b connected to the inclined surface 41a.
At this time, the beam shape of the laser light is controlled so that the inclined surface 41b having the inclination angle θb is formed.
As described above, the inclined surface 41a and the inclined surface 41b having different inclination angles can be formed.

In the case where three or more inclined surfaces having different inclination angles are formed, laser light irradiation with different beam shapes may be repeated further.
As illustrated above, the recess 41 is formed by sequentially irradiating laser beams having different beam shapes to predetermined positions on the main surface (the surface 31a or the surface 31b) of the metal foil 31.

  As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 1 Inner tube, 2 Metal halide, 5 Outer tube, 11 Light emission part, 12 Sealing part, 31 Metal foil, 31a surface, 31b surface, 31c area | region, 32 electrode, 41 Recessed part, 41a inclined surface, 41b inclined surface, 41c Central axis, 100 discharge lamp, 101 burner, 102 socket, 111 discharge space, D1 outer edge dimension, D2 cross-sectional dimension, La laser beam, Lb laser beam, θa tilt angle, θb tilt angle

Claims (6)

A light emitting part having a discharge space therein;
A sealing portion provided at an end of the light emitting portion;
An electrode having one end provided in the discharge space and the other end provided in the sealing portion;
A metal foil provided inside the sealing portion, joined to the electrode, and having a plurality of recesses on the main surface;
Comprising
Each side wall of the plurality of recesses is provided with a plurality of inclined surfaces having different inclination angles,
In the thickness direction of the metal foil, each opening portion of the plurality of recesses is provided at a position on the surface of the metal foil,
The discharge lamp which the outer edges of the said adjacent recessed part are contacting in planar view, or the outer edges of the said adjacent recessed part are spaced apart . The dimensions of the cross section perpendicular to the central axis in each of the opening portions of the plurality of recesses, each of the plurality of inclined surfaces longer claim than the size of the section vertical to the central axis in the connecting portion between the plurality of recesses The discharge lamp according to 1. The discharge lamp according to claim 1 or 2, wherein the plurality of recesses are not provided in a region of the metal foil where the electrodes are joined. A method for producing the discharge lamp according to any one of claims 1 to 3,
A step of forming a plurality of recesses in the main surface of the metal foil by sequentially irradiating laser beams having different beam shapes to predetermined positions on the main surface of the metal foil,
In the step of forming the plurality of recesses, a plurality of inclined surfaces having different inclination angles are formed on the side walls of the plurality of recesses, and the respective openings of the plurality of recesses are opened in the thickness direction of the metal foil. The portion is provided at a position on the surface of the metal foil, and is formed so that the outer edges of the adjacent concave portions are in contact with each other or the outer edges of the adjacent concave portions are separated from each other in plan view. A method for manufacturing a discharge lamp.   In the step of forming the plurality of recesses, the dimension of the cross section perpendicular to the central axis in each opening portion of the plurality of recesses is the center axis in the connection portion between the plurality of inclined surfaces of the plurality of recesses. 5. The method of manufacturing a discharge lamp according to claim 4, wherein the discharge lamp is made longer than a vertical cross-sectional dimension.   6. The method of manufacturing a discharge lamp according to claim 4, wherein, in the step of forming the plurality of recesses, the plurality of recesses are not formed in a region where the electrode of the metal foil is joined.

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