EP1632988A2 - Method and apparatus for producing a lamp - Google Patents

Abstract

Production of lamp, preferably incandescent lamp pinched at one end, having a lamp bulb, into which a luminous mechanism and supply leads are inserted through a feed opening, the lamp tube being sealed by pinching the region of the feed opening, comprises filling the lamp bulb (2) through the feed opening before the pinching. An independent claim is also included for an apparatus for carrying out the method, comprising (i) holder for lamp bulb and a luminous mechanism; (ii) feeding and evacuating device via which inert and/or filling gas can be fed or evacuated through a feed opening in the lamp bulb for the luminous mechanism; (iii) laser for heating the pinch region of the lamp bulb; and (iv) pinching device for making a gas-tight pinch in the region of the feed opening.

Description

Technical area

The invention relates to a method for producing a lamp, preferably a one-side pinched incandescent lamp according to the preamble of claim 1, an apparatus for carrying out such a method and a lamp produced by such a method.

State of the art

Such, for example, from DE 196 23 499 Al known method is used for example for the production of halogen incandescent lamps. In principle, however, lamps of a different type, for example discharge lamps, can also be produced by this method. In the known method, a piston tube is initially provided with a rounded tip on the end, on which an axially projecting Pumprohransatz is formed. Furthermore, the piston tube is reshaped in a mold by blowing inert gas into a lamp envelope, through the open feeding device of which a frame is used, on which at least one helix and the power supply lines are formed. Furthermore, the Pumprohr approach is partially separated, so that a pump tube can be attached to the resulting open cannula. The feed opening for the frame is then sealed gas-tight by a pinch and evacuated via the pump tube of the lamp envelope enclosed inside and filled with a filling gas containing halogens. In a final operation, the pump tube is then melted, so that the lamp bulb is closed and the two power supply lines protrude from the pinch.

A similar process is also described in US Pat. No. 4,756,701, in which, however, the design of the contour in the region of the dome is not so exact can be, as is the case in the prior art according to DE 196 23 499 Al.

A disadvantage of these solutions is that in the area of the dome through the melted pump tube always an axial projection, the so-called pump tip remains, which can lead to shadows and disturbing structures with frontal illumination. Furthermore, it is disadvantageous that these known methods are relatively expensive, since the pump tube must first be attached and separated again in a subsequent work step and the remaining pump tip must be closed.

Presentation of the invention

It is an object of the present invention to provide a method according to the preamble of claim 1 and an apparatus for carrying out this method and a lamp, in which the above-described disadvantages are eliminated.

This object is achieved with respect to the method by the combination of features of claim 1, with respect to the apparatus for performing the method by the features of claim 13 and with respect to the lamp by the feature combination of the independent claim 16.

Particularly advantageous embodiments can be found in the dependent claims.

According to the filling of a lamp bulb is not - as in the prior art - via a specially attached pump tube but on the already existing feed opening through which a bulb was introduced into the lamp envelope. By means of this solution, a dome of the lamp bulb remote from this supply opening can be made smooth-surfaced, without a pump tip, so that the front-side illumination can be substantially improved compared to conventional solutions. The manufacture of the lamps is also simplified compared to the generic method, since the separate steps for forming and separating / welding the pump tube can be omitted.

It is preferred that the filling and squeezing in the region of the feed opening in a gas-tightly sealed space, preferably a pressure vessel perform in which both a holder for the lamp bulb, the light source and the squeezing device are arranged.

The filling can then be done by flooding the pressure vessel with the filling gas or via a suitable Gaseinfüllvorrichtung.

The method can be further simplified if the heating of the area of the lamp bulb to be squeezed is effected by high-energy radiation, for example laser radiation. The laser itself can be arranged outside the space / pressure vessel, wherein the laser beam can enter the container interior via one or more laser windows.

Depending on the lamp to be produced, it may be advantageous to let the laser beam enter from two sides or at one side, wherein at least in the latter case the lamp should be rotated in order to heat the pinch region on both sides, while in the former case a simultaneous heating of diametrically arranged surfaces takes place ,

The quality of the pinch seal can be significantly improved if, by deflecting a laser spot by means of a scanner, a predetermined beam profile is generated, by which a directed heating of the pinch region is made possible. This beam profile is set, for example, so that the intensity of the feed opening, d. H. gradually increases towards the lower edge of the lamp bulb in order to avoid the radiation losses in this area. In the case in which the lamp bulb is held over a lamp tongs or the like, it is preferred to increase the radiation intensity also to this lamp tongs in order to minimize radiation losses via the forceps, so that a continuous and uniform heating of the pinch region is ensured.

In halogen incandescent lamps, the lamp body is usually formed of quartz glass - to minimize SiO ₂ formation (that is, formation of SiO ₂ vapor), the laser power can be reduced depending on the Einstrahldauer. The resulting during heating SiO ₂ vapor or quartz smoke is preferably removed by suction, for example by means of a suction tube, which is directed to the region to be heated of the lamp vessel.

It was found that a laser power between 300 watts and 2500 watts and a Eintrahldauer in the range of 2 seconds to 20 seconds is sufficient.

An important field of application of the method according to the invention consists in the production of so-called reflector lamps, in which the lamp bulb is expanded like a reflector and provided with a reflection layer, since no pump tip is formed in the region of a tip terminating the reflector, which inevitably arises in the lamps produced by conventional methods ,

Brief description of the drawings

• Figur 1 eine Vorderansicht einer nach dem erfindungsgemäßen Verfahren hergestellten Halogenglühlampe;
• Figur 2 eine Seitenansicht der Halogen-Glühlampe aus Figur 1;
• Figur 3 eine Unteransicht der Halogen-Glühlampe aus Figur 1;
• Figur 4 eine Seitenansicht einer nach dem erfindungsgemäßen Verfahren hergestellten Halogen-Reflektorlampe;
• Figur 5 ein Grundschema einer erfindungsgemäßen Vorrichtung zur Durchführung des Verfahrens und
• Figur 6 eine Schemadarstellung einer Lampenhalterung der Vorrichtung aus Figur 5.

In the following the invention will be explained in more detail by means of embodiments with reference to drawings. Show it:

• FIG. 1 shows a front view of a halogen incandescent lamp produced by the process according to the invention;
• Figure 2 is a side view of the halogen incandescent lamp of Figure 1;
• Figure 3 is a bottom view of the halogen incandescent lamp of Figure 1;
• FIG. 4 shows a side view of a halogen reflector lamp produced by the process according to the invention;
• FIG. 5 shows a basic diagram of a device according to the invention for carrying out the method and
• 6 shows a schematic representation of a lamp holder of the device from FIG. 5.

Preferred embodiments of the invention

The invention will be explained below with reference to low-voltage halogen incandescent lamps. However, as already mentioned, the application of the method according to the invention and the device according to the invention is by no means restricted to such types of lamps but chosen here only by way of example.

Figures 1 to 3 show an embodiment of a halogen incandescent lamp, which may be designed for low voltage operation or mains voltage and which can be used in the living room or as a furniture lamp.

The incandescent lamp 1 has a lamp bulb 2, which in the raw state (dashed in Figure 2) has approximately the shape of a hollow cylinder, wherein an end portion is formed by a crowned curved tip 4. This is unlike traditional ones Halogen incandescent lamps are not provided with a pump tip 6, which is indicated in triggers in Figure 1, but smooth surface running, so that the frontal radiation is not hindered. The lamp bulb 2 is made of quartz glass or tempered glass.

At the lower end portion of the lamp bulb 2 in FIGS. 1 and 2, a pinch seal 8 is formed, via which a frame 10 is held gas-tight in the lamp bulb 2. The frame 10 has a helix 12 whose axis is coaxial with the lamp axis (vertical in Figure 1). By the helical wire two power supply lines 14, 16 are formed, which are connected to arranged in the pinch seal 8 molybdenum foils 18, 20. These are in turn connected to outside the pinch seal 8 lying base pins 22, 24. The pinching takes place via molded crimping jaws, so that in the side view according to FIG. 2 the cylindrical base body is flattened so that, according to FIG. 3, a profile results which is trapezoidally widened at its outer narrow sides 26, 28. The apparent in Figure 3 profile of the pinch 8 is determined by the geometry of the Formquetschbacken.

The interior of the lamp bulb 2 is filled in halogen lamps with a filling gas containing a proportion of a halogen (30 to 3000 ppm). The adjusting when switching on the lamp halogen circuit is well known, so that explanations are unnecessary.

A peculiarity of the above-described incandescent lamp 1 is that the evacuation and filling with filling gas is not carried out - as usual - via an attached to the pump tip 6 pump tube but from the crushing by the raw state (dashed lines in Figure 2) open supply port 30 of the lamp bulb 2 - A pump tip 6 is not required, the dome 4 can therefore be performed with high optical quality.

4 shows a variant of an incandescent lamp 1 is shown, which is designed as a halogen reflector lamp. The basic structure of this lamp is the same as in the above-described embodiment, ie, in a lamp bulb 2, a frame 10 is received, wherein the lower end portion of the lamp bulb 2 is sealed gas-tight over the pinch seal 8. In contrast to the above-described embodiment, the pinch seal 8 merges into a neck 32, which then widens in a funnel shape to form a reflector 34, which is likewise crowned but more domed dome 4 is closed. The funnel-shaped peripheral walls of the reflector 34 are provided with a silver coating 36 acting as a reflection layer.

Both lamps (Figures 1 to 3, Figure 4) may additionally be provided with a special interference filter coating, is reflected back over the heat to the coil, so that less energy must be supplied from the outside to keep the coil to operating temperature. This infrared coating (IRC) allows a higher light output and thus a saving of energy costs for operating the lamp. If such a coating is applied, the lamp envelope 2 is formed with an elliptical cross-section.

As mentioned above, the crushing and thus the gas-tight closing of the lamp bulb 2 downwards in the prior art after shaping the outer contour of the lamp bulb 2 by means of Formquetschbacken 35, via which also adjoining the pinch seal 8 areas of the lamp envelope 2 are reshaped , The heating to deformation temperature is usually carried out in the conventional solutions by gas burners over which the area of the pinch seal 8 is heated.

FIG. 5 shows a device with which the method according to the invention can be carried out, in which the lamp bulb 2 is filled from below via the feed opening 30 and the lamp bulb 2 is heated by means of laser radiation.

According to FIG. 5, the device has a pressure chamber 38, in which one or more of the incandescent lamps 1 to be filled and squeezed are arranged. This is held by a device which is shown in detail in Figure 6.

The pressure chamber 38 can be filled or evacuated by means of an inert gas line 40 with inert gas. Furthermore, a filling gas cannula 42 immersed in the pressure chamber 38, which dips into the feed opening 30 shown in Figure 2 and is connected to a filling gas line 44.

As an alternative to the cannula and the entire pressure chamber - as indicated by dashed lines - are flushed via the filling gas line 44, so that can be dispensed with the cannula 42.

The heating of the pinch region is effected by means of a laser 46, wherein in the illustrated embodiment, a CO ₂ laser is used with a wavelength of 10.6 microns - of course, other types of lasers are used.

The laser beam emitted by the laser 46 is directed by a suitable focusing optics, for example comprising a prism 48, a parabolic mirror 50 and a pivotable scanner mirror 52 through a laser window 54 of the pressure chamber 38 to the pinch region of the lamp bulb 2. In the exemplary embodiment shown in FIG. 5, the laser beam enters into the pressure chamber 38 on one side, so that only one side of the lamp bulb 2 is heated in each case. Such a focusing optics requires that the incandescent lamp 1 is rotatably received in the pressure chamber 38, so that the pinch region can be uniformly heated on both sides. In this rotatable mounting of the incandescent lamp 1 can be omitted if the laser beam is divided over the prism 48 into two sub-beams, which then enter from left and right two laser window 54 in the pressure chamber 1 - d. h., The radiation pattern shown in Figure 5 is then mirrored about the vertical axis. However, it may also be advantageous in this variant to turn the bulb 1 during heating.

The drive of the scanner mirror 52 is controlled so that the laser spot sweeps over a predetermined area a, wherein by controlling the scanner drive, a predetermined beam profile is adjustable over which the heating is controlled path-dependent. This will be explained with reference to FIG.

FIG. 6 shows the incandescent lamp 1 in the clamped state, the area swept by the laser beam being indicated by dashed lines.

The undeformed lamp bulb 2 (see Figure 2) is held by a pliers 54 which is rotatable about the vertical axis. The frame 8 introduced into the lamp envelope 2 through the feed opening 30 is held in its predetermined relative position to the lamp envelope 2 by a frame holder 58 which is likewise rotatably mounted. Through the frame holder, the cannula 42 extends through which the filling gas in the interior of the lamp envelope 2 can be pressed.

Depending on the process scheme (feeding of filling gas via the cannula 42 or by flushing the pressure chamber 38), the filling gas is adjusted to a slight overpressure, which may be between 190 and 300 mbar depending on the lamp volume.

After or during the filling of the lamp bulb, the laser 46 is driven and the piston rod 56 and the frame holder 58 synchronously rotated at a rotational speed between 180 to 600 U / min. The scanner mirror drive is controlled so that adjusts a beam profile, as shown in Figure 6 right. D. h., The intensity profile increases in the region of the pliers 56 slightly to compensate for radiation losses over the piston lower edge. The intensity profile also increases towards the lower edge, ie toward the feed opening 30, in order to compensate for the radiation losses in this area - this achieves a very uniform heating of the sections to be squeezed. The Einstrahldauer and the laser power is adjusted so that the SiO ₂ development (that is, the evaporation of SiO ₂ or the formation of quartz smoke) is minimized. Preliminary tests showed that an irradiation time in the range between 2 to 20 seconds at a laser power between 300 and 2500 watts can be.

To further minimize the evolution of SiO ₂ , the laser power can be reduced stepwise during the irradiation period. In principle, it could be stated that the SiO ₂ formation can be reduced with decreasing laser power and at the same time with a somewhat longer irradiation time.

After heating the pinch region, the shaping crimping jaws 60, 62 (dash-dotted line in FIG. 6) are closed and the pinching or another geometry shown in FIGS. 1 to 3 is formed.

In order to remove the SiO ₂ vapor formed during the heating, it is additionally possible to provide an extraction with a suction tube in the pressure chamber 38. The suction tube is directed to the area to be heated, for example the pinch, in order to suck off the quartz smoke produced during the heating.

Disclosed are a method and a device for producing a lamp and a lamp produced by this method, in which the filling of a lamp envelope closed on one side takes place through a supply opening for a light source. As a result, a dome of the lamp bulb smoothly run without pump tip.

Claims (17)

Method for producing a lamp, preferably a single-ended incandescent lamp (1), comprising a lamp bulb (2) into which a lighting means (12) and power supply leads (14, 16; 22, 34) are inserted through a feed opening (30) the lamp bulb (2) is sealed by squeezing in the region of the feed opening (30), characterized in that the filling of the lamp bulb (2) takes place before squeezing through the feed opening (30). The method of claim 1, wherein the filling and crushing in a pressure vessel (3 8) is performed. The method of claim 1 or 2, wherein the filling via a cannula (42) or by flooding of the pressure vessel (38). Method according to one of the preceding claims, wherein the pinch region is heated by high-energy radiation, preferably by laser radiation to the deformation temperature. A method according to claim 4, wherein the laser (46) is arranged outside the pressure vessel (38) and the laser beam enters the container interior via a laser window (54). A method according to claim 5, wherein the laser beams are directed from two sides towards the pinch region of the lamp (1). Method according to one of claims 4 to 6, wherein the laser beam sweeps over a beam profile corresponding to the pinch region. Method according to claim 7, wherein the energy input to the feed opening (30) and to a clamping point for the lamp bulb (2) increases. Method according to one of claims 4 to 8, wherein the laser power is reduced after a predetermined Einstrahldauer. Method according to one of claims 4 to 9, wherein the Einstrahldauer 2 to 20 seconds and the laser power is between 300 and 2500 watts. Method according to one of claims 4 to 10, wherein the resulting during heating quartz smoke or SiO ₂ vapor is sucked off. Method according to one of the preceding claims, wherein the lamp (1) is rotated during the heating. Device for carrying out the method according to one of the preceding claims, comprising a holder for a lamp bulb (2) and a light source (12) inserted therein, a feed and suction device (40, 44) via the inert and / or filling gas through a feed opening (30) of the lamp bulb (2) for the lighting means (12) can be fed or sucked, with a laser (46) for heating the pinch region of the lamp bulb (2) and with a squeezing device (60, 62) for creating a gastight bruise ( 8) in the region of the feed opening (30). Incandescent lamp according to claim 13, wherein the lamp bulb (2), the holder (56, 58) and the squeezing device (60, 62) are arranged in a closed space, preferably a pressure container (38) having at least one laser window (54). Apparatus according to claim 13 or 14, wherein the holder (56, 58) is rotatably mounted. Lamp, in particular produced according to one of the preceding claims, wherein the lamp bulb (2) on one of base pins (22, 24) remote dome (4) is made flat. A lamp according to claim 16, wherein said lamp is a reflector lamp having a reflective layer (36) applied to a surface of the lamp envelope.

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