EP2154706A2 - Foil for lamps and electric lamp with such a foil and corresponding production method - Google Patents

Abstract

The foil (6) has a zone (10) of grooves (11) that are structured parallel to each other in a specific region facing the interior of a bulb (2). An inner power line (5) is passed over the zone and welded to the foil. Independent claims are included for the following: (1) power supply system; (2) electric lamp; and (3) manufacturing method of power supply system.

Description

Technical area

The invention is based on a film for lamps which use a film seal. This can be a melting or crushing. The lamps may be in particular halogen incandescent lamps or high-pressure discharge lamps. The invention also relates to such lamps and also to a method of producing a power supply system comprising such a foil

State of the art

Normally, foils are welded together with the associated power supply leads, which lead into the interior or exterior of a bulb of a lamp, using aids such as welding pastes or welding tapes (usually Pt) or coatings of the foil such as Ru, see DE-A 19961551 , On the other hand, purely mechanical mounting methods (clamping the film or folding the film) are also being tested. In EP-A 944 112 the film is trimmed and turned over.

Presentation of the invention

An object of the present invention is to provide an improved concept for a film that is machine-friendly and allows a simple and secure connection of the power supply lines. Another object is to provide a power supply system as well as a lamp, both of which are both simple and inexpensive can be produced. Another task is to specify a manufacturing method for each.

This first object is achieved by the characterizing features of claim 1. The further objects are achieved by the characterizing features of claims 6 and 9.

Particularly advantageous embodiments can be found in the dependent claims.

According to the invention, the film is provided with an array of slots which are produced within the film. The field consists of at least three slots arranged side by side. Typical and particularly effective is a field of about 10 to 25 slots. The slots are preferably parallel to each other. For example, the field is rectangular. The slots are preferably arranged obliquely to the longitudinal axis of the film. Typically, the film itself is rectangular.

The dimensions of the slots are chosen so that they are adapted to be attached to the film power supply. As a power supply is a thin wire, preferably the power supply is a single or double helical wire. The best results are achieved with a single coiled wire.

The field of slots serves to ensure that a power supply to be fastened substantially parallel to the longitudinal axis of the film can be better welded without the need for the usual auxiliary means. For this reason, the slot direction must be arranged obliquely to the direction of the power supply. A possible Angle against the longitudinal axis is 10 to 90 °, preferably a range of 30 to 70 °, particularly suitable is an angular range of 30 to 45 °.

The slots are most easily generated by a laser treatment. Preferably, a high-quality pulsed Nd-YAG micromachining laser is used for this purpose.

• Der Übergangswiderstand wird rein geometrisch erhöht.
• Der Übergangswiderstand wird noch weiter durch spontane Oxidation der Ränder der Schlitze erhöht. Mit Oxidation ist hier allgemein auch teilweise Oxidation, Spratzer von Molybdän und Schmauchspuren gemeint.
• Das Aufschmelzen der Folie, die bevorzugt aus Molybdän oder dotiertem Molybdän gefertigt ist, gelingt leichter, weil der beim folgenden Widerstandsschweißen zur Verbindung der Folie mit der Stromzuführung die seitliche Wärmeableitung geringer ist. Damit ist die Gefahr, dass die zu verschweißende Stromzuführung verdampft oder an der oberen Schweißelektrode kleben bleibt, minimiert. Die untere Schweißelektrode ist unterhalb der Folie angeordnet und unkritisch.
• das Aufschmelzen der Folie ist auch deswegen erleichtert, weil der effektiv wirksame Querschnitt der Folie geringer ist.

The width d of the slots is 5 .mu.m to 200 .mu.m, advantageously it is at most 100 .mu.m. The distance f between the slots is preferably 50 to 500 μm, in particular 100 to 400 μm. In this case, f should be at most equal to 5 AD when AD is the outer diameter of the power supply to be fixed. In practice, in the case of a simple wire, this is the diameter of the wire, in the case of a single-coil power supply, it is the outside diameter of the primary winding. By choosing the dimensions of the field, it is ensured that a number of parameters for the weld are decisively improved:

• The contact resistance is increased purely geometrically.
• The contact resistance is further increased by spontaneous oxidation of the edges of the slots. By oxidation is meant in part also generally oxidation, scratches of molybdenum and traces of smoke.
• The melting of the film, which is preferably made of molybdenum or doped molybdenum, succeeds more easily, because the lateral heat dissipation is lower in the following resistance welding for connecting the film to the power supply. This is the danger that the to be welded power supply evaporates or sticks to the upper welding electrode minimized. The lower welding electrode is arranged below the film and not critical.
• the melting of the film is also facilitated because the effective effective cross-section of the film is lower.

Under these circumstances, the parameters for the weld can be specifically optimized by the number, width and spacing of the slits each to a specific power supply. There are no expensive additional materials such as welding pastes or welding bands needed. Even time-consuming coatings and the time for dabbing with pastes or for folding the film eliminated. In addition, it is advantageous that existing machines can be converted to the new method with little effort.

The films used for this purpose are conventional films used in the construction of lamps, preferably a molybdenum film, which is possibly suitably doped, as has likewise been known for a long time. Typical dimensions of the foil are: width is 3 mm and length is 7 mm. A typical thickness is 30 μm. The field of slots has a typical dimension of 2mm width and 0.8mm length.

Thus, an additional consumption of film material is not required, in contrast to Falt process.

The thus treated film is preferably used in quartz glass flask. Lamps with such pistons may be incandescent or discharge lamps.

• Zunächst wird im Bereich der zukünftigen Schweißstelle einer Folie ein Feld von Schlitzen ausgeschnitten.
  Dies geschieht bevorzugt mit Hilfe eines Laserstrahls, der durch eine Scanneroptik gelenkt wird. Es kann jedoch auch mechanisch hergestellt werden. Dieses Verfahren kann selbstverständlich auch auf der anderen Seite der Folie, wo die äußere Zuleitung ansetzt, verwendet werden. Beim thermischen Schnitt mittels hochenergiereicher Laserstrahlung kann zusätzlich mit Schutzgas gespült werden um den Grad der Oxidation auf der Folie gezielt zu beeinflussen.
• Auflegen der Stromzuführung auf die Folie, wobei die stroz auf dem Feld zu liegen kommt.
• Schweißung der Stromzuführung an die Folie, wobei bevorzugt Widerstandsschweißen eingesetzt wird.

The manufacturing process has the following steps:

• First, a field of slots is cut out in the area of the future weld of a film.
  This is preferably done with the aid of a laser beam, which is guided by a scanner optics. However, it can also be produced mechanically. Of course, this method can also be used on the other side of the film where the outer lead starts. During thermal cutting by means of high-energy laser radiation, shielding gas can additionally be purged in order to influence the degree of oxidation on the film in a targeted manner.
• Place the power supply on the foil, causing the stroke to come to rest on the field.
• Welding the power supply to the film, preferably resistance welding is used.

In principle, the new concept is suitable for a connection mediated by means of welding or soldering between an internal or external power supply and a foil. It is sufficient in the simplest case even that the structure of the field on the film not with slits but purely by a pretreatment of the film, which leads to melting in a line-like manner or a grid-like manner, is achieved. Of course, a combination of pure melting and slitting is also suitable.

The advantage of such pretreatment is in any case that the molybdenum of the film melts more easily during welding, because the weld cross-section is smaller. In addition, there is less heat dissipation at the welding point of the power supply over the film. The inner is preferred Power supply a coil or a coil with core wire. It is also advantageous that the contact resistance at the cut edges assumes a well-defined value.

Such a panel can also be combined with other measures, such as a film tab, by first creating an array of slits or fuses and then slitting a portion of the film like a window around that area of the panel.

The concept is particularly suitable for the connection of the film to the internal power supply, since their diameters are usually relatively small, so that the welding of this power supply is particularly critical. Typical diameters of the wire of the power supply are down to 15 microns, in a primary winding, the outer dimensions are down to about 50 microns. Of course, the concept can also be used alone or in addition to the connection of the film to the external power supply.

The foil material itself is the usual one used in the construction of lamps, for example molybdenum or doped or coated molybdenum or even tantalum etc. The thickness and shape of the foil can also be selected as usual. Typical are some tens of μm and a lancet shape of the film.

Such films themselves are typically cut substantially rectangular, with a longitudinal side, which is preferably parallel to the later lamp axis, and a shorter transverse side, which is preferably transverse to the later lamp axis. Deviations from this rule are of course possible and do not affect the basic concept of the invention.

According to the invention, at least one field is recessed in the film. This can be achieved by punching or by using high-energy radiation, in particular a laser. Typical cutting times per foil are less than a second. The slot has a typical width of 5 to 250 μm. The basic shape of the slot is usually rectangular, but it can have any other shapes, such as triangular, wavy or rounded. It is essential that the width at one point has the adaptation to the power supply described above.

At high cutting speeds and in particular at the beginning and end of a laser cut, it happens that the kerf is not completely cut through in some places. These fine webs within the laser cut usually have a rounded shape, since the pulsed Nd-YAG laser with downstream laser scanner optics generates the slits so that one dot is cut out or sublimed out per laser pulse. Due to the high pulse frequency in the kilohertz range, these laser points are usually so overlapping that typically a wavy cut contour is produced. By means of higher cutting speeds it is achieved that the individual points no longer overlap and thus a small rounded web stops within the kerf. In extreme cases, even a maximum web distance s between the points can be set, which is in the range 1d to 3d of the kerf width d.

Due to the dynamics of the laser scanner head, the web distance can change within a cutting line. Depending on the laser type and manufacturer, it may be that at the beginning and at the end of the line, the web width becomes smaller or completely disappears. When cutting out the slots, cutting speeds of up to 5000 mm / sec can be achieved. In general, therefore, there is usually a combination of pure slots and interrupted by webs slots.

Possibly. For example, a plurality of such fields, preferably two, may be mounted on a foil. As a result, either a plurality of power supply lines can be held mechanically at the same time, or the holder of a power supply can be improved by means of these second slots by means of a second weld.

The cutting out of the slot along the cutting edge takes place for example by mechanical punching or by high-energy means such as plasma or laser radiation. The concrete way of cutting it is not important. However, high energy means are advantageously applicable for quick and easy processing.

This system is well suited for metal halide or halogen incandescent lamps, but also versatile for other purposes.

Brief description of the drawings

Figur 1

eine Halogenglühlampe mit neuartiger Folie;

Figur 2

eine Folie mit einem Feld von Schlitzen;

Figur 3

eine Entladungslampe mit einem Feld von Furchen;

Figur 4

ein weiteres Ausführungsbeispiel eines Feldes von Schlitzen;

Figur 5

ein weiteres Ausführungsbeispiel eines Feldes von Schlitzen.

In the following, the invention will be explained in more detail with reference to several embodiments. The figures show:

FIG. 1

a halogen bulb with a new kind of foil;

FIG. 2

a foil with a field of slits;

FIG. 3

a discharge lamp with a field of furrows;

FIG. 4

another embodiment of a field of slots;

FIG. 5

another embodiment of a field of slots.

Preferred embodiment of the invention

An embodiment of a halogen incandescent lamp 1 shows FIG. 1 , It has a piston 2 made of quartz glass, which is sealed with a pinch seal 3. In the interior of the piston, a luminous element 4 is attached, which is connected via two inner power supply lines 5, each with a film 6 in the pinch seal 3. The power supply lines are typically made of tungsten or molybdenum, or similar. and have a diameter of 15 to 200 microns, depending on the wattage of the lamp. The flask contains a common halogen-containing filling. The type of filling is not important here. Instead of a luminous body, the piston may also contain two electrodes.

The film 6 is each made of molybdenum. In the region of the half facing the interior of the piston, it has a field 10 of furrows 11 which are structured parallel to one another. The inner power supply 5 is guided over the field and there welded to the film 6. This power supply is preferably a single-wound wire (primary winding).

In FIG. 2 a foil 6 with a panel 19 of slots 20 is shown in detail. Where d is the width of a slot and f is the distance between two slots. Typical For example, about 10 to 25 slots are similarly arranged in a rectangular field of width b and length a. The slits are inclined by 45 ° even against the longitudinal direction of the film. This ensures that as many slots as possible cross the power supply. This usually means that the length of the slots is different. However, it is not excluded that the length of the slots is the same, so that the field itself is oblique to the longitudinal axis.

It is also not excluded that the parameters d and f change within the field. This can be achieved by tilting the laser beam (laterally or longitudinally). Due to the different distances of the film surfaces to the laser optics, the focus diameter of the beam on the Mo film and thus also the kerf width d changes.

It can e.g. but also specifically the distance f within a field can be changed by e.g. To obtain approximately equal volume elements between 2 webs. Thus, the lancet-shaped cross-section of the Mo film can be approximately taken into account with the thinning edges.

FIG. 3 shows a further embodiment of a high-pressure discharge lamp 30 with a known metal halide filling. In this case, the film 31 is not treated so that slots are formed, but only a structured field 32. The laser power is made smaller, so that instead of slits on the surface of the film only furrows 33 arise in which the film is melted or even only oxidized was roughened while doing so. There are also combinations of slots and furrows possible. In general, however, furrows provide worse results than slots, because then the effects of the invention are significantly less pronounced.

In this case, the film 31 is used for a sealing based on a melting, wherein the discharge vessel 29 made of quartz glass with two cylindrical necks 28, which contain the films 31, is provided. The inner power supply lines are shafts 27 which terminate at electrodes 26 here.

Preferably, the film 31 is here provided with two fields, a field 32 for the electrode shaft as an inner power supply and a field 35 for the external power supply 36th

The field 35 for the external power supply is here equipped with lattice-like arranged grooves 39. This embodiment is not feasible with slots. In this case, a field of parallel Anschmelz furrows is first generated by laser. Thereafter, the angle is changed and a second field of fused furrows is overlaid. The parameters of the two fields can be different, ie in particular d and f can be chosen differently.

FIG. 4 shows an embodiment of a film 6, wherein the field 40 is arranged from slots around.

FIG. 5 shows a further embodiment of a film 6, in which slots 51 are used, which are interrupted by webs 52. The length of the slot parts 51 is designated by x. The length of the interruptions or webs 52 with y. Such a design improves the stability of the film and can with higher-Watt lamps the Reduce current density in the areas between the slots. Best results are achieved when the ratio x: y is in the range 0.3: 1 to 3: 1. Because of the dynamics of the laser, this statement is not generally true for all slits, but only for a central region of the field, especially for the middle third of the length of a slit at all those slits in the field that have maximum length and hence not at the edge of the field lie. The cutting speeds are 10 mm / sec up to 10000 mm / sec. In this case, a point overlap is no longer secured throughout. the result is slits or holes one behind the other like in FIG. 5 shown. A typical pulse frequency of the laser is 2 to 100 kHz. A typical diameter of a single hole is 5 to 50 μm. The distance between the individual holes is often in the range of the diameter of the hole up to three times this diameter or the smaller dimension of the longitudinal slot. A typical arrangement of the slit field on the film is a 3 mm wide film, with the distance of the field from the edge of the film being about 0.5 to 1 mm, respectively.

The production of the slots or grooves is most easily achieved by means of high-energy radiation such as an Nd: YAG laser or CO2 laser with extremely small focus beam diameter less than 0.5 mm. Preferably, this laser is operated in the pulse mode and the laser beam is guided by means of a scanner optics or by means of a micromirror.

The production of the slits by means of laser processing, etc. can be done both before and after the chemical edge etching of the Mo band. That means the laser processing On the one hand on the finished Mo film, on the other hand also on half-finished unetched Mo band (rolled Mo wire as well as rolled Mo sheet) possible. Although some of the traces of smoke / scratches / oxidations are etched away here, the increase in the lateral cut edges is still present. The advantage is that light oxidations / smuts are etched away and the residual stresses introduced by the laser processing into the Mo foil disappear after the chemical etching and relaxation and cleaning annealing of the finished Mo foil.

Claims (13)

Film for lamp construction with a substantially rectangular shape with a longitudinal and a transverse axis, characterized in that the film has at least one field in its interior, which consists of a plurality of juxtaposed structures, in particular of at least three structures. A film according to claim 1, characterized in that the structures are at least partially slits. A film according to claim 1, characterized in that the structures are at least partially furrows of melts or oxidized areas. A film according to claim 1, characterized in that the slots are arranged inclined or oblique to the longitudinal axis of the film, in particular in an angular range of 10 ° to 90 °. A film according to claim 1, characterized in that the individual structures are regular with respect to their width d and their distance f. A film according to claim 1, characterized in that the film consists of molybdenum, optionally doped. A film according to claim 2, characterized in that the slots are at least partially interrupted by webs, wherein in a central region, the ratio of the length x of the web portions and the length y the webs in particular in the range 0.3: 1 to 3: 1. Power supply system for a lamp consisting of film and at least one associated power supply, wherein a film having a field of structures according to one of the preceding claims 1 to 6 is connected to the power supply characterized in that the power supply in the field of the field is applied to the film and is welded to this, in particular by means of resistance welding. Power supply system according to claim 6, characterized in that the power supply is a Primärgewickel. Power supply system according to claim 6, characterized in that the maximum distance f between the slots corresponds at most to 5 times the outer diameter of the current supply. Electric lamp, comprising a glass containing a filling piston and at least one seal and a light bulb mounted in the bulb, wherein the lamp is connected via an inner power supply to a film in the seal and the film is connected to an external power supply, characterized in that the film has at least one array of structures according to one of claims 1 to 6 and at least one of the power supply lines is welded to the film in the region of the field. A method of manufacturing a power supply system according to claim 8 comprising a foil and a power supply attached thereto, comprising the steps of: - Generating a field of structures on the film in the area of future attachment of the power supply; - applying the power supply to the film, wherein the power supply is applied in the field of the field; - Attaching the power supply to the film by means of a welding operation. A method according to claim 12, characterized in that the fastening takes place by resistance welding.

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