TUBE LAMP WITH LEADFRAME

Description

Technical area

[0001] The present invention relates to a tubular lamp with a light engine based on a leadframe, in particular an LED retrofit tubular lamp, e.g. of the T5 and T8 types. State of the art

[0002] Fluorescent tube lamps are increasingly being replaced by retrofit tube lamps with semiconductor light-emitting elements (e.g., light-emitting diodes, LEDs). Such retrofit tube lamps typically comprise a housing in the form of a tubular bulb that is at least partially translucent or transparent, with two end caps at either end of the tubular bulb, a light engine containing a plurality of LEDs, and an electronic driver that supplies the LEDs with electrical energy with the required electrical parameters (current, voltage) for their operation.

[0003] The term "light engine" is commonly used for the arrangement of the plurality of LEDs and a support structure for the LEDs, which includes electrically conductive structures and / or cables through which the LEDs can be supplied with electrical energy from the electrical driver.

[0004] Many retrofit LED tube lamps use a circuit board for the light engine, to which the LEDs are attached, for example, soldered. Such circuit boards are typically manufactured by etching a blank containing a copper layer deposited on an electrically non-conductive substrate. This results in high copper consumption and, accordingly, high manufacturing costs and a significant environmental impact.

[0005] German patent application DE 10 2017 109 853.4 discloses the construction of the light engine of a retrofit tube lamp on a so-called wiring board. Wiring boards consist of strips of an electrically conductive material (e.g., aluminum) laminated between electrically insulating, flexible layers (e.g., polyimide). The desired circuit design can then be achieved by punching out portions of the electrically conductive strips. The LEDs can be connected to the electrically conductive strips through openings in one of the electrically insulating layers.

[0006] Despite all the advantages over printed circuit boards, the production of wiring boards is complex and expensive.

[0007] From US2014268779A1, WO 2013 / 144858 A1, US 2004 / 0252501 A1, US 2016 / 0255694 A1 and US 2015 / 0276140 A1, lighting devices are known in which the holding structure for the LEDs has a leadframe. Description of the invention

[0008] Based on the known prior art, it is an object of the present invention to provide a lighting device with a simplified light engine.

[0009] The problem is solved by a lighting device having the features of the independent claim. Advantageous further developments emerge from the subclaims.

[0010] Accordingly, a lighting device is proposed with a translucent tubular bulb, at least one end cap arranged at one end of the tubular bulb, and a light engine arranged in the tubular bulb. According to the invention, the light engine has a leadframe on which a plurality of semiconductor lighting elements, in particular LEDs, are arranged, wherein the leadframe has at least three parallel tracks, wherein at least two of the tracks have a plurality of sections, wherein the sections of a first track are arranged offset from the sections of a second track so that they each overlap over half a section, wherein at least some of the semiconductor elements are directly connected to both a section of the first track and a section of the second track, and wherein a third track of the leadframe is continuous over the length of the leadframe.Leadframes are electrically conductive structures that are punched or cut from a metal sheet (e.g., by laser cutting or waterjet cutting) and do not require an electrically insulating substrate (such as circuit boards) or electrically insulating, flexible layers (such as wiring boards). To produce a leadframe, the conductor tracks are punched or cut out of a sheet of metal, leaving transport strips and connecting bars to stabilize the punched sheet for further processing. The transport strips and connecting bars are removed at a later time, e.g., when the leadframe is sufficiently stabilized by the electrical components attached to it.

[0011] The semiconductor light elements are attached using an SMD soldering technique (SMD stands for "surface-mount device"), in which the soldering points on the punched-out sheet metal parts (conductor tracks) are coated with solder paste, then populated with the semiconductor light elements, and finally heated by infrared radiation from a melting furnace, which melts the solder paste. This connects the semiconductor light elements to the conductor tracks.

[0012] The leadframe is a flat structure that has two opposing and essentially parallel surfaces spaced apart by the sheet thickness. The leadframe can be made, for example, from a cost-effective material, such as steel, or a material with high thermal conductivity, such as copper, or a visually high-quality metal, such as brass. The sheet thickness is preferably in the range of 0.1 mm to 2 mm, more preferably in the range of 0.2 mm to 0.8 mm. Materials that are suitable for printed circuit boards (PCBs) are particularly suitable. In addition, the leadframe can be coated, for example with a Sn, Zn, Au, Ag, Pt, Pd, or Ni layer, and / or the surfaces of the leadframe can be partially or completely roughened. The surfaces of the leadframe can also be coated with a highly reflective coating, e.g., with a white or light-colored paint or varnish layer (especially solder mask).

[0013] The production of a leadframe is therefore easier than that of a wiring board or a printed circuit board. The conductive structures can also be selected more flexibly than with a wiring board. The thermal conductivity of the metallic leadframe also improves heat dissipation from the semiconductor lighting elements during operation.

[0014] In the context of the present disclosure, "arranged on the leadframe" means that the corresponding component is attached to the leadframe and is in electrical connection with the leadframe.

[0015] The components can be arranged on one or both surfaces of the leadframe. Especially with semiconductor lighting elements, mounting them on both sides of the leadframe can achieve better all-round light distribution.

[0016] In one embodiment, the lamp has two end caps arranged at opposite ends of the tubular bulb. Such a lamp can, for example, be of the T5 or T8 design.

[0017] In one embodiment, the lamp has precisely one end cap arranged at one end of the tubular bulb. The other end of the tubular bulb can be sealed with the tubular bulb material. Such a lamp can be designed, for example, as a retrofit lamp for a compact fluorescent lamp.

[0018] In one embodiment, the tubular bulb is sealed in a gas-tight manner. Preferably, the gas-tight tubular bulb is filled with a filling gas, which in particular comprises a gas with high thermal conductivity. The gas with high thermal conductivity can be, for example, helium, oxygen, or hydrogen, or a mixture of these (e.g., helium / hydrogen or helium / oxygen). By filling the tubular bulb with a gas with high thermal conductivity, the dissipation of heat from the semiconductor lighting elements during operation can be further improved.

[0019] The filling gas may contain additional gaseous components that can be used to achieve high internal vessel pressures and / or optical light modifications, such as light filtering and improved light output. For example, the filling gas may also contain nitrogen, argon, air, neon, carbon dioxide, nitrogen dioxide, or sulfur hexafluoride.

[0020] Advantageously, the proportion of the gas with high thermal conductivity in the filling gas is 1 - 100%, preferably 50 - 90%.

[0021] In practice, the gas pressure in the vessel is between 0.01 and 1200 hPa, with a preferred gas pressure being between 0.1 and 1000 hPa.

[0022] In one embodiment, the illuminant comprises an electronic driver with a plurality of electronic components, wherein at least one of the electronic components is arranged within the tubular bulb. One, several, or all of the electronic components can be arranged within the tubular bulb. Preferably, electronic components that are expected to emit gas during operation are arranged outside the tubular bulb. This prevents the gases from altering the filling gas present in the tubular bulb and thus potentially altering its properties.

[0023] Another advantage of using a leadframe as a carrier for the semiconductor lighting elements is that it largely reduces outgassing through the carrier (in known lighting devices, for example, through the circuit board or the wiring board).

[0024] It is advantageous to arrange as many of the electronic driver's electrical components as possible within the preferably gas-tight tubular bulb. This provides the best possible protection for the lamp's components from external influences and allows the lamp to be used in environments with demanding environmental conditions, such as street lighting, greenhouses, coastal regions with high salinity, production environments with aggressive gases, etc.

[0025] Depending on the application environment, semiconductor light elements with a correspondingly suitable spectral range can be selected. All semiconductor light elements can emit light in essentially the same spectral range, or two or more different types of semiconductor light elements can be used, e.g., blue-emitting and red-emitting semiconductor light elements for plant lighting.

[0026] In one embodiment, at least one of the electronic components arranged within the tubular bulb is mounted on the leadframe. This allows the leadframe to provide the electrical connection of the electronic component. A printed circuit board on which further electronic components of the electronic driver are arranged can thus be as small as possible. This further reduces possible outgassing inside the tubular bulb through the printed circuit board.

[0027] In one embodiment, the leadframe has a central region on which the plurality of semiconductor light-emitting elements is arranged, and at least one end region on which at least one of the electronic components of the electronic driver is arranged. This allows, in particular, the electronic components of the electronic driver that are larger than the semiconductor light-emitting elements to be arranged at the ends away from the semiconductor light-emitting elements, where they impede the light emission by the semiconductor light-emitting elements as little as possible.

[0028] However, electronic components of the electronic driver can also be arranged in the central area of ​​the leadframe.

[0029] If the electronic components of the electronic driver are arranged in both end regions of the leadframe, the leadframe may have additional connecting sections that electrically connect the two end regions.

[0030] To prevent such connecting sections, which extend over the entire length of the leadframe, from causing unwanted electromagnetic interference ( electromagnetic interference, To avoid interference (e.g., EMI), these connecting sections can be connected to adjacent sections of the leadframe at one or more points via capacitors. This procedure is described, for example, in German patent application DE 10 2017 103 184.7.

[0031] In one embodiment, the width of the leadframe in at least one end region is greater than the width of the leadframe in the central region. This provides sufficient space for the electronic driver, while the central region with the semiconductor lighting elements can be designed as narrow as possible. For reasons of material savings (environmental and cost advantages), it is advantageous to design the central region as narrow as possible. For example, the width of the leadframe in the central region is between approximately 6 mm and approximately 10 mm, preferably between approximately 7 mm and approximately 8 mm. In particular, if no connecting sections for parts of the electronic driver are required in both end regions of the leadframe, the width of the central region can be approximately 7 mm. With additional connecting sections, the width of the central region can reach up to approximately 10 mm.

[0032] In one embodiment, the width of the leadframe is variable along its length. In particular, the width of the leadframe can vary linearly, preferably continuously linearly, along its length, for example, from a first width at a first end of the leadframe to a second width, which is smaller than the first width, at a second end of the leadframe. This allows sufficient space for the electronic driver to be provided at the wider end of the leadframe.

[0033] A design of the leadframe with a continuously linearly changing width also has the advantage that several leadframes can be manufactured from one starting material without waste by alternately arranging a narrow and a wide end of adjacent leadframes next to each other.

[0034] Production of multiple leadframes without waste from a single source material can also be achieved if only one of the end sections of the leadframe is wider than the middle section, preferably approximately twice as wide as the middle section. Then, during production, the wide end sections of the first, third, etc. leadframes can be arranged next to each other on one side, and the wide end sections of the second, fourth, etc. leadframes can be arranged on the other side, i.e., the corresponding leadframes are rotated 180°.

[0035] In one embodiment, the electronic driver is a linear driver. Linear drivers for LED lamps are known, for example, from international patent applications WO 2007 / 144365 A1 and WO 02 / 23956 A2. The linear drivers disclosed in these publications can also be used in embodiments of the luminous device according to the invention.

[0036] A linear driver has the advantage of requiring very few electronic components. The core of a linear driver is a current regulator, which is usually available as an integrated circuit (IC). In the publications mentioned above, a transistor or an LM317AT from National Semiconductor is used as the current regulator. Alternatively, a BP5151HC from Bright Power Semiconductor Co. can be used.

[0037] With a linear driver, proper cooling is especially important for the current regulator. Therefore, the current regulator is preferably located on the leadboard, allowing the heat generated during operation to be effectively dissipated.

[0038] In one embodiment, the electronic driver is embedded in a filling material. The filling material can comprise a polymer mass (e.g., casting resins and / or high-viscosity adhesives made of silicone, polyurethane, polyacrylic, polyester, polyamide, polyolefin, and / or epoxy) and / or a filler (e.g., glass beads, sand, lime, ceramic powder such as Al2O3, or a mixture of these). The polymer mass can be translucent (in particular, transparent). The driver embedded in the filling material can further be provided with a sealing layer (e.g., polymer). The polymer mass can be temperature-, UV-, moisture-, and / or time-curing.

[0039] By embedding the electronic driver in such a filler material (potting), the thermal connection of the electronic driver to the glass bulb can be improved. In particular, the heat generated by the current regulator and / or the capacitor during operation can be more effectively dissipated to the wall of the glass bulb and the end cap.

[0040] Furthermore, potting the electronic driver can encapsulate potential outgassing from the electronic components of the light engine with the semiconductor lighting elements. This can be particularly useful for electrolytic capacitors used as smoothing capacitors.

[0041] Such potted electronic drivers are preferably located on one side of the lamp (i.e., only in one end cap), since the filling process in the lamp, which is closed on one side, can be done by gravity. The electronic driver can be positioned either on the leadframe or on a separate circuit board.

[0042] In the case of a separate circuit board, the electronic driver can also be pre-potted outside the lamp to enclose the electronic components and reduce any outgassing from the electronic components and the separate FR4 circuit board. Independently of this, the pre-potted driver can also be connected to the glass bulb using a subsequent potting process.

[0043] In a further embodiment, the lamp interior is filled with a translucent (especially transparent) filler material (e.g., glass beads, glittering acrylic rhinestones with a diamond effect, polymer granules, or a mixture thereof) even in the area of ​​the semiconductor lighting elements. This can improve heat dissipation and influence the optical appearance of the lamp. Such an embodiment can have a particularly high-quality appearance. Furthermore, it is possible to dispense with the slurry coating or internal matting of the glass bulb, which is normally done to conceal the lamp interior from the outside.

[0044] To save weight and filler material, the bulb can be partially coated with such a translucent filler material (optical scattering particles). The bulb can be tilted and filled with a mixture of casting resin / adhesive with optical fillers (glass beads, ceramic powder, acrylic rhinestones / glitter stones with a diamond effect, etc.). The low-viscosity casting resin-filler mixture runs downwards on the side opposite the semiconductor light elements (i.e., the side towards which the light is emitted). The lamp is preferably closed on one side, and the electronic driver can be arranged at the bottom with respect to gravity and thus embedded in the filler material at the same time.Alternatively, the lamp can first be filled with the low-viscosity pure casting resin / adhesive, followed by a slight curing so that the casting resin / adhesive becomes highly viscous, and finally the optical scattering particles are filled in, which stick to the high-viscosity casting resin / adhesive.

[0045] As an alternative or in addition to casting resins and / or polymer adhesives, so-called hotmelt adhesives can also be used, i.e. adhesives that are initially in solid form, e.g. as powder or granules, and only become liquid when heated.

[0046] The filling process can be carried out entirely using solid materials (hot melt granules and fillers such as glass beads, sand, lime, or ceramic powder). The connection to the glass bulb and / or the electronic components is achieved by subsequent heating, which melts the hot melt adhesive.

[0047] Since hot-melt adhesives and polymer compounds (polymer casting resin, polymer adhesive) are more expensive than the fillers, the amount of hot-melt adhesive or polymer compound can be kept as low as possible using a three-step process: 1. Introducing the pure fillers into the driver area of ​​the one-sidedly closed lamp. 2. Applying the hot-melt granules onto the filler granules. 3. Melting the hot-melt sealing layer and sealing the driver area.

[0048] This has the additional advantage that the hotmelt sealing layer is melted spatially separated from the electronic components. Ideally, the sealing layer is only in contact with the temperature-resistant lead frame metal, the temperature-resistant soft glass bulb, and the temperature-stable filler material (glass beads, sand, etc.).

[0049] According to the invention, the leadframe has one or more projections, in particular deep-drawn sections, embossings, etc. The projections are located on the underside of the leadframe, i.e. on the surface on which no semiconductor lighting elements are arranged. On the upper side of the leadframe, i.e. on the surface on which the semiconductor lighting elements are arranged, the projections then appear as depressions. In the region of the projections, i.e. essentially around the projections on the underside of the leadframe and / or on the projections, the leadframe is provided with an adhesive with which the leadframe is attached to the inside of the tubular bulb.

[0050] The projections reduce the distance between the leadframe and the inner surface of the tubular piston, so that a smaller amount of adhesive is required when bonding the leadframe to the tubular piston at these points.

[0051] The distance between two semiconductor light-emitting elements is typically approximately 17 mm. To achieve a sufficient number of adhesive points, the distance between two recesses can be 2, 3, 4, or 5 times the distance between the semiconductor light-emitting elements, in particular approximately 34 mm, 51 mm, 68 mm, or 85 mm. Other distances are also possible. The projections can also be distributed unevenly along the light engine.

[0052] Alternatively, in an embodiment not claimed, or additionally, the leadframe can be secured by means of retaining clips attached to the inside of the tubular piston. Such retaining clips are known from international patent application WO 2011 / 064305 A1.

[0053] In one embodiment, the leadframe has bent sections, which can be created by punching and bending on one side. These can increase the cooling surface for electronic components subject to high thermal stress.

[0054] The leadframe can also be attached to the inside of the tubular bulb using laser welding. A laser is used to heat the leadframe through the glass of the bulb at specific points where it contacts the inside of the bulb. The heat is transferred to the glass, melting it. This fuses the leadframe to the glass.

[0055] Preferably, the material of the leadframe is selected so that, in addition to the required electrical conductivity and solderability, it has a similar thermal expansion coefficient to the glass of the tubular bulb. For example, the tubular bulb can be made of conventional soda-lime glass with a thermal expansion coefficient of approximately 9.8 ppm / K, and the leadframe can be made of DC01 steel with a thermal expansion coefficient of approximately 10.5 ppm / K. For a 1.5 m long lamp at a temperature difference of 100 K (e.g., -20 °C to 80 °C), the difference of 0.7 ppm / K corresponds to a difference in linear expansion of approximately 0.1 mm. Such a difference can be easily compensated for by the aforementioned fastening methods. In particular, this enables the leadframe to be directly bonded to the inside of the tubular bulb.

[0056] In one embodiment, the electronic driver comprises a printed circuit board on which at least one of the electronic components is arranged. The electronic components of the electronic driver can thus be arranged all on the printed circuit board, all on the leadboard, or partially on the printed circuit board and partially on the leadboard. The printed circuit board can be arranged entirely within the tubular bulb or at least partially in an end cap of the lamp.

[0057] The printed circuit board can be connected to the leadframe via at least one electrically conductive connecting element.

[0058] Two circuit boards for the electronic components of the electronic driver can also be provided, with each circuit board being arranged entirely within the tubular bulb or at least partially within an end cap of the lamp. The electronic components of the electronic driver can then be distributed across the two circuit boards. Accordingly, two electrically conductive connecting elements are provided for connecting the circuit board and the leadframe.

[0059] It can also be provided that a first circuit board is arranged entirely within the (possibly gas-tight) tubular bulb, and a second circuit board is arranged outside the tubular bulb, at least partially in an end cap of the lamp. This allows electronic components that exhibit undesirable outgassing to be arranged outside the tubular bulb, while the other electronic components are arranged inside the tubular bulb, where they are protected from environmental influences.

[0060] In one embodiment, the leadframe has a bent portion that serves as a connecting element. For this purpose, one of the punched or cut-out metal surfaces of the leadframe can be at least partially bent into the shape of a connecting element. The material used for the leadframe can have spring properties that ensure that the bent portion of the leadframe presses against corresponding contact surfaces on the printed circuit board.

[0061] In one embodiment, the light engine further comprises an electrically conductive means, in particular a cable, extending from a first end of the leadframe or a printed circuit board arranged at the first end of the leadframe to a second end of the leadframe or a printed circuit board arranged at the second end of the leadframe. This allows an electrical connection to be achieved between the two ends of the leadframe or between sections of the electronic driver arranged at both ends, without providing corresponding sections in the leadframe. This allows the leadframe to be designed as narrow as possible.

[0062] In one embodiment, the light engine has one or more stabilizing sections made of an insulating material, which are introduced locally, preferably in a point-like and / or linear manner, into spaces in the leadframe in order to fasten sections of the leadframe to one another and preferably to space them apart from one another.

[0063] In this context, "local" specifically means that the leadframe is not fully or largely embedded in a housing or casing, such as a plastic one. The stabilizing sections are therefore characterized by being specifically provided at locations on the leadframe where stabilization and, if necessary, spacing is required to ensure the mechanical and electrical functionality of the LED module. The stabilizing sections can, in particular, be provided in spaces, such as gaps, in such a way that unintentional bending and contacting of electrically insulated sections of the leadframe is prevented.

[0064] The stabilizing sections are preferably made of polymer and / or glass and / or ceramic and / or cement and / or SMD components with insulating properties. SMD components with insulating properties include: resistors with extremely high resistance in the mega- or giga-ohm range, reverse-biased diodes, capacitors for direct current applications, and similar. Epoxy resin adhesive has proven to be an advantageous polymer; its thermal expansion coefficient is in the same order of magnitude as a polymer housing of semiconductor light-emitting elements such as LEDs, and thus does not cause thermal stress on the semiconductor light-emitting elements under changing temperature stress. Alternatively or additionally, other polymers can also be used, such as thermoplastics, for example, PC, PMMA, PBT, thermosets, or elastomers, such as silicones.

[0065] This stabilizes the light engine's leadframe particularly well, so that it is easy to handle during assembly in the tubular bulb, even after the initially stabilizing connecting bars have been removed.

[0066] Such stabilization can be particularly advantageous where longer sections of the leadframe run next to each other without being connected to each other by electronic components (such as components of the electronic driver or capacitors for reducing electromagnetic interference).

[0067] Preferably, the two surfaces of the leadframe are largely free of contact with the material of the stabilizing sections. "Largely" means that more than half, preferably more than 80%, of both surfaces (considered individually) are not in contact with the stabilizing sections. Preferably, both surfaces (considered individually) of the leadframe are largely uncovered (in the sense defined above), i.e., they also have no contact with LEDs, SMD components, solder joints, etc. This particularly improves heat dissipation via the leadframe to the gas contained in the tubular bulb.

[0068] For the same reasons, the individual stabilization sections are preferably distinguishable, i.e., they do not overlap to form a structure the size of the leadframe. The extent of the individual stabilization sections therefore preferably corresponds only to a small part of the overall extent of the leadframe. In particular, the leadframe preferably has electrically insulating spaces, such as gaps or gap sections, that are not filled and thus completely penetrate the leadframe in the thickness direction. The extent of the stabilization sections preferably corresponds substantially to the size of the gaps to be bridged. Short description of the characters

[0069] Preferred further embodiments are explained in more detail by the following description of the figures. These show: Figure 1 shows an embodiment of a tube lamp; Figure 2 shows a schematic representation of the electrical circuit of the LEDs in the embodiment according to Figure 1; Figure 3 shows an embodiment of the connection between the printed circuit board and the leadframe; Figure 4 shows a schematic arrangement of a plurality of leadframes of one embodiment during production; Figure 5 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production; Figure 6 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production; Figure 7 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production; Figure 8 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production; Figure 9 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production; Figure 10 shows a schematic representation of the electrical circuit of a linear driver for the LEDs; Figure 11 shows a schematic arrangement of a plurality of leadframes of a further embodiment during production;Figure 12 schematically shows a side view of a leadframe according to ; Figure 11 ; Figure 13 schematically shows a leadframe with an additional connecting cable; Figure 14 schematically shows an arrangement of several leadframes of a further embodiment during production; Figure 15 schematically shows an arrangement of several leadframes of a further embodiment during production; Figure 16 an embodiment of a lighting device with a leadframe according to Figure 15 ; Figure 17 schematically shows an embodiment of a first end region of a leadframe; Figure 18 schematically shows an embodiment of a second end region of a leadframe; Figure 19 schematically shows the first end region of a leadframe from Figure 17 with electronic components in a lamp; Figure 20 schematically shows the first end region of a leadframe made of Figure 17 without electronic components in a lamp. Detailed description of preferred embodiments

[0070] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the various figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancies.

[0071] In Figure 1 An embodiment of a tubular lamp is partially shown. The tubular lamp has a translucent tubular bulb 1, at each end of which an end cap 2 is arranged. Two connecting pins 3 are attached to the end cap, with which the tubular lamp can be held in a corresponding socket and via which the tubular lamp can be supplied with electrical energy.

[0072] Located inside the end cap 2 and extending from there into the interior of the tubular bulb 1 is an electronic driver 4, whose electronic components 5 are arranged on a circuit board 6. The driver 4 is securely held inside the tube lamp by means of a retaining rail 7 glued to the inside of the tubular bulb 1.

[0073] A leadframe 8 is used as the light engine, on which several light-emitting diodes (LEDs) 9 are arranged. The leadframe 8 comprises several sections 10 that have been punched or cut out of a metal sheet (e.g., DC01 steel). In the illustrated embodiment, the leadframe 8 essentially has three parallel tracks, with the first track 11 (shown as the rear track in the figure) and the second track 12 (shown as the middle track in the figure) each consisting of several sections 10. The third track 13 (shown as the front track in the figure), on the other hand, is continuous over the length of the leadframe 8. The terms "front", "middle", and "rear" refer to the representation in the figure and are used synonymously with "first", "second", and "third" tracks below.The sections 10 of the rear track 11 and the middle track 12 are arranged offset from one another so that they each overlap over half a section 10. Between the right-hand area (in the illustration) of a section 10 of the rear track 11 and the left-hand area (in the illustration) of a section 10 of the middle track 12, two LEDs 9 are connected in parallel. Between the right-hand area (in the illustration) of a section 10 of the middle track 12 and the left-hand area (in the illustration) of a section 10 of the rear track 11, two LEDs 9 are also connected in parallel, so that the first-mentioned group of parallel LEDs and the second-mentioned group of parallel LEDs are connected in series. This pattern continues over the length of the leadframe 8.

[0074] The first (left) section of the rear track 11 is connected to a first output terminal of the electronic driver 4. The last pair with two parallel LEDs 9' (in Figure 1 not shown, but in Figure 4 (see figure) is connected to the right-hand section of the middle track 12 and to the front (continuous) track 13. This establishes the connection to a second output terminal of the electronic driver 4 and closes the circuit. Instead of two LEDs, a 0-ohm resistor or another conductive element can be used for the connection between the middle track 12 and the front track 13. Alternatively or additionally, one or more connecting bridges can be retained to close the circuit, i.e., when the individual sections of the leadframe are separated, these connecting bridges are not severed.

[0075] Thus, the LEDs are arranged as a series circuit of parallel-connected pairs of LEDs, as shown schematically in Figure 2 is shown.

[0076] In Figure 3 1 shows an embodiment of the connection between the circuit board of the electronic driver 4 and the leadframe 8. Two contact clips 26, each with a substantially U-shaped contact area 14, are plugged onto the circuit board 6 of the driver 4 in such a way that the U-shaped contact areas 14 contact correspondingly arranged contact points on the circuit board 6, which represent the two output connections of the driver 4. Extending downward from the lower leg of the U-shaped contact areas 14 are connecting areas 27, which contact corresponding sections 10 of the leadframe 8. This creates an electrical connection between the circuit board of the electronic driver 4 and the leadframe 8.

[0077] Alternatively, the left end (in the illustration) of the front track 13 and the first (left) section of the rear track 11 are bent to create two essentially U-shaped contact areas 14 into which the printed circuit board 6 of the driver 4 is inserted. The U-shaped contact areas 14 then contact correspondingly arranged contact points on the printed circuit board 6, which represent the two output connections of the driver 4. As a result, the corresponding sections 10 of the leadframe 8 assume the function of the contact clips 26.

[0078] In Figure 4 is a schematic diagram of an arrangement of several leadframes 8 as used in an embodiment of a lighting device according to Figure 1or can be used in other embodiments, during production. The leadframes 8 were punched or cut out of a sheet 15 (e.g., by laser cutting) and are connected to a frame 17 and to each other via connecting webs 16. In Figure 4 Four leadframes 8 are shown, but a different number of leadframes 8 can also be produced from one sheet 15.

[0079] Each leadframe 8 has three tracks, an upper track 11 (corresponding to the first track or rear track in Figure 1 ), a middle lane 12 (corresponding to the second lane or middle lane in Figure 1 ) and a lower track 13 (corresponding to the third track or front track in Figure 1 ). The terms "upper", "middle", and "lower" refer to the representation in the figure and are used synonymously with "first", "second", and "third" lanes.

[0080] The upper track 11 and the middle track 12 are each composed of several sections 10. The lower track 13 is continuous over the length of the leadframe. The sections 10 of the upper track 11 and the middle track 12 are offset from one another so that they each overlap over half a section 10. Between the right-hand area (in the illustration) of a section 10 of the upper track 11 and the left-hand area (in the illustration) of a section 10 of the middle track 12, two LEDs 9 are connected in parallel to one another. Between the right-hand area (in the illustration) of a section 10 of the middle track 12 and the left-hand area (in the illustration) of a section 10 of the upper track 11, two LEDs 9 are also connected in parallel to one another, so that the first-mentioned group of parallel LEDs and the second-mentioned group of parallel LEDs are connected in series. This pattern continues over the length of the leadframe 8.For reasons of clarity, not all LEDs 9 are shown.

[0081] The last pair, with two parallel LEDs 9', is connected to the right-hand section of the middle track 12 and to the lower (continuous) track 13. Instead of two LEDs, a 0-ohm resistor or another conductive element can be used for the connection between the middle track 12 and the lower track 13. Alternatively or additionally, one or more connecting bridges 16 can be retained to close the circuit, i.e., when the individual sections of the leadframe 8 are separated, these connecting bridges 16 are not severed.

[0082] To stabilize the leadframe 8, stabilizing sections can be provided between the sections 10 and / or between the tracks 11, 12, 13 of the leadframe 8. Preferably, in particular, the continuous lower track 13 is locally connected to the adjacent middle track 12 by stabilizing sections (insulating material or insulating SMD components).

[0083] When all LEDs 9 are mounted on the leadframe 8 and connected to it, the connecting webs 8 can be severed and the leadframes 8 can be separated from the frame 17 and from each other.

[0084] The width of the leadframes 8 is preferably about 7 mm. This provides sufficient space for the LEDs 9 on the leadframe 8 without requiring unnecessary material for the leadframe 8. The width of the upper track 11 and the middle track 12 is preferably about (2.0 ± 0.1) mm. The width of the lower track 13 is preferably about (1.6 ± 0.1) mm. The width of the punched openings between the tracks is preferably (0.7 ± 0.1) mm. The width of the punched openings between the sections 10 in a track is preferably (1.0 ± 0.1) mm. The length of the sections 10 of the upper track 11 and the middle track 12 is preferably about (67.6 ± 0.5) mm. The length of the leadframe 8 is preferably 17 sections 10, i.e. about 1166 mm. This means that a lamp with a total length of 1200 mm (also called a 4-foot lamp) still has space for an electronic driver.If a punching tool that is shorter than the leadframe is to be used multiple times, the leadframe can also be initially manufactured with a length of 18 sections and then one section removed later. Fewer sections are shown in the illustration for clarity. The dimensions mentioned above can also be used for subsequent leadframes.

[0085] With four LEDs per section, this results in 66 or 68 LEDs, depending on whether the connection between the middle track 12 and the lower track 13 is made by two LEDs 9' or by a 0-ohm resistor. With an operating voltage of 3 V per LED, this results in a total operating voltage of 198 V or 204 V. Such a voltage can be generated, for example, with a linear driver.

[0086] In the embodiment according to Figure 4the first section (left in the illustration) of the upper track 11 has a length that corresponds to 3 / 4 of the length of the other sections 10. The last section (right in the illustration) of the upper track 11 also has a length that corresponds to 3 / 4 of the length of the other sections 10. The first section (left in the illustration) of the middle track 12 has a length that corresponds to 1 / 4 of the length of the other sections 10. Accordingly, the last section (right in the illustration) of the middle track 12 also has a length that corresponds to 1 / 4 of the length of the other sections 10.

[0087] However, the first (in the figure on the left) and / or last (in the figure on the right) sections can also be made longer, which can simplify the connection to the driver, especially if end sections of the leadframe are formed into contact areas (see Figure 3 ).

[0088] In Figure 51 schematically shows an arrangement of several leadframes 8 in a further embodiment during production. Each leadframe 8 has a central region 18 and an end region 19.

[0089] The middle section 18 of the leadframes 8 in Figure 5 corresponds to the Figure 4 The leadframe shown here is not explained again here. However, other leadframe designs in the central area 18 can also be used.

[0090] The end region 19 of the leadframes 8 is intended for electronic components 5 of the driver 4. The exact division of the end region 19 into leadframe sections depends on the design of the driver 4 and is therefore not shown in detail here.

[0091] The width of the leadframes 8 is preferably approximately 7 mm. This provides sufficient space on the leadframe 8 for the LEDs 9 and the electronic components 5 of the driver without requiring unnecessary material for the leadframe 8.

[0092] In Figure 6 1 schematically shows an arrangement of several leadframes 8 in a further embodiment during production. Each leadframe 8 has a central region 18 and two end regions 19, 20.

[0093] The end regions 19, 20 of the leadframes 8 are intended for electronic components 5 of the driver 4. The exact division of the end regions 19, 20 into leadframe sections depends on the design of the driver 4 and is therefore not shown in detail here. One embodiment of the division of the end region of the leadframe 8 is shown as an example in the Figures 17 to 20shown. The division of the driver 4 into two end regions 19, 20 allows the end regions 19, 20 to be made smaller and thus the non-illuminating region to be distributed between the two ends of the lamp.

[0094] The middle section 18 of the leadframes 8 in Figure 6 essentially corresponds to the Figure 4 shown leadframes and will not be explained again here. However, other designs of the leadframe in the central area 18 can also be used. In addition to the Figure 4 In addition to the section of the leadframe 8 taken over (ie the three upper tracks 11, 12, 13), the leadframe has two further tracks 21 which serve to connect the two parts of the electronic driver 4.

[0095] Preferably, the tracks 21 are locally connected to each other and / or to the adjacent lower track 13 by stabilizing sections (insulating material or insulating SMD components). Stabilization can be achieved, in particular, by capacitors, which can prevent or at least reduce unwanted electromagnetic interference.

[0096] The width of the leadframes 8 is preferably approximately 10 mm. This provides sufficient space on the leadframe 8 for the LEDs 9 and the electronic components 5 of the driver without requiring unnecessary material for the leadframe 8. The additional tracks 21 require a wider design of the leadframe 8 compared to the previous embodiments.

[0097] In Figure 71 schematically shows an arrangement of several leadframes 8 in a further embodiment during production. Each leadframe 8 has a central region 18 and an end region 19.

[0098] The end region 19 of the leadframes 8 is intended for electronic components 5 of the driver 4. The exact division of the end region 19 into leadframe sections depends on the design of the driver 4 and is therefore not shown in detail here.

[0099] The end region 19 is twice as wide as the middle region 18, so that more space is available in the end region 19 for the electronic components 5 of the driver 4. The width of the middle region 18 of the leadframes 8 is preferably approximately 7 mm, and the width of the end region is therefore approximately 14 mm. This provides sufficient space on the leadframe 8 for the LEDs 9 and the electronic components 5 of the driver without requiring unnecessary material for the leadframe 8.

[0100] The leadframes 8, where the end area 19 is arranged on the left side (in the illustration), correspond (except for the width of the end area 19) to the leadframes from Figure 5 . The leadframes 8, in which the end region 19 is arranged on the right side (in the figure), are rotated by 180° in comparison.

[0101] In Figure 81 schematically shows an arrangement of a plurality of leadframes 8 in a further embodiment during production. The width of the leadframes 8 decreases from a first width at a first end of the leadframe 8 to a second width, which is less than the first width, at a second end of the leadframe 8. The width at the second end is preferably no more than about 7 mm, more preferably no more than about 5 mm. The width at the first end is preferably about 20 mm. This allows sufficient space for the electronic driver to be provided at the wider end of the leadframe.

[0102] For reasons of clarity, the division of leadframe 8 into sections 10 is not shown here.

[0103] In Figure 9An arrangement of several leadframes 8 is shown schematically in a further embodiment during production. The arrangement of the tracks 11, 12, 13 and sections 10 of the leadframe 8 essentially corresponds to that of Figure 4 In addition to the LEDs 9, electronic components 5 of the driver 4 are arranged in the area of ​​the light engine, utilizing the division of the two upper tracks 11, 12 into sections 10.

[0104] As electronic driver 4, for example, a linear driver can be used, as shown schematically in Figure 10The electronic driver has a rectifier consisting of four diodes D, at the output of which a smoothing capacitor C1 is provided. One terminal of the smoothing capacitor C1 is connected to ground. A BP5151HC integrated circuit IC is used for the linear driver. The CS terminal of the IC is connected to ground via a resistor R1. The VD terminal of the IC is connected to ground via a capacitor C2. The VD terminal of the IC is also connected to the cathode end of the series-connected LEDs via a resistor R2. The Drain terminal of the IC is directly connected to the cathode end of the series-connected LEDs. The GND terminal of the IC is connected to ground. The BP5151HC integrated circuit IC is usually available in the ESOP8 package, as well as in Figure 10The four NC terminals have no function. If the integrated circuit with the same functionality is used in the SOT223 or TO252 format, it can be connected as shown in Figure 9 shown, together with the resistors R1 and R2 and the capacitor C2, directly in the area of ​​the light engine on the leadframe.

[0105] The rectifier and the smoothing capacitor C1 (in Figure 9 not shown) can then be arranged in one or two end areas of the leadframe or on a separate circuit board.

[0106] In Figure 11 An arrangement of several leadframes 8 in a further embodiment according to the invention is schematically shown during production. The leadframes 8 essentially correspond to the leadframes from Figure 4 .

[0107] Approximately in the middle of each section 10 of the central track 12, a recess 22 (seen from the top of the leadframe 8) is provided, which can be produced, for example, by embossing or deep drawing. Figure 12 shows a schematic side view of a leadframe 8 with recesses 22 (again without LEDs) in a tubular bulb 1. The recesses 22 and the projections resulting from them on the other side of the leadframe 8 serve to reduce the distance between the leadframe 8 and the inside of the curved tubular bulb 1. This creates a narrow adhesive gap, which reduces the amount of adhesive to be used.

[0108] In Figure 13 A leadframe 8 is shown schematically in a further embodiment. The leadframe 8 essentially corresponds to the leadframes from Figure 4, however, does not have a lower track 13. The electrical connection between the right end of the leadframe 8 (in the figure) and a driver (not shown) at the left end of the leadframe (in the figure) can be made, for example, with a cable 23 (schematically indicated).

[0109] In Figure 14 An arrangement of several leadframes 8 in a further embodiment during production is shown schematically. The leadframes 8 essentially correspond to the leadframes from Figure 4 .

[0110] The three tracks 11, 12, 13 of the leadframes 8 are connected to one another by stabilizing sections 24 made of insulating material, thereby increasing the stability of the leadframes 8. In addition to the arrangement of the stabilizing sections 24 shown, other arrangements can also be used. For reasons of clarity, not all stabilizing sections 24 are shown.

[0111] In Figure 151 schematically illustrates an arrangement of several leadframes 8 in a further embodiment during production. Each leadframe 8 has two tracks, an upper track 11 and a lower track 12. The terms "upper" and "lower" refer to the representation in the figure and are used below as synonyms for "first" and "second" tracks.

[0112] The upper track 11 and the lower track 12 are each made up of several sections 10. The sections 10 of the upper track 11 and the lower track 12 are offset from one another so that they each overlap by half a section 10. An LED is connected between the right-hand area (in the illustration) of a section 10 of the upper track 11 and the left-hand area (in the illustration) of a section 10 of the lower track 12. LED 9 is also connected between the right-hand area (in the illustration) of a section 10 of the lower track 12 and the left-hand area (in the illustration) of a section 10 of the upper track 11, so that the LEDs are connected in series. This pattern continues over the length of the leadframe 8. For reasons of clarity, not all LEDs 9 are shown. The leadframe 8 therefore causes all LEDs 9 to be connected in series. A continuous track for returning the electrical connection is not provided.

[0113] In Figure 16 an embodiment of a lighting device is partially shown, in which the In Figure 15 shown leadframe 8 is used. The leadframe 8 is attached to the inside of a tubular piston 1 in such a way that it runs from an open end of the piston 1 to a closed end of the piston 1, runs there along the end face 25 and then runs from the closed end of the piston 1 back to the open end of the piston 1. Since both ends of the leadframe 8 are thus located at the open end of the piston 1, they can be connected there to an electronic driver (not shown) without the need for a continuous track to return the electrical connection.

[0114] Accordingly, the other leadframes shown above can also be used in such a light source without a continuous third track.

[0115] The Figures 9 to 15The leadframes 8 shown can each also be provided with one or two end sections 19, 20 for electronic components 5 of a driver 4, as shown in the Figures 5 to 8 is shown.

[0116] In the Figures 17 to 20 is shown by way of example how the end region or the end regions 19, 20 of a leadframe 8 can be divided into sections 10' so that the electronic components 5 of the driver 4 can be arranged directly on the leadframe 8.

[0117] Figure 17 shows schematically on the left in the figure a first end region 19 of the leadframe 8. On the right in the figure the middle region 18 of the leadframe is shown with three tracks 11, 12, 13 (in the figure below) of the light engine, each consisting of several sections 10.

[0118] Figure 18shows schematically on the right side of the figure a second end region 20 of the leadframe 8. On the left side of the figure the middle region 18 of the leadframe is shown with three tracks 11, 12, 13 (in the figure below) of the light engine, each consisting of several sections 10.

[0119] The two upper continuous tracks 21 (in the Figures 17 and 18 the two upper tracks) serve to connect the two driver gates, whose components 5 are arranged in the two end areas 19, 20 of the leadframe 8.

[0120] Sections 10, 10' of leadframe 8 are shown in the Figures 17 and 18 connected to each other with connecting bridges 16. These can be severed after the electronic components 5 of the driver 4 are attached to the leadframe 8.

[0121] In Figure 19A schematic section of a lamp is shown with a leadframe 8 on which the electronic components 5 of the driver 4 are directly arranged. The arrangement of Figure 19 without the electronic components 5 of the driver 4 is in Figure 20 shown. Figure 20 how the leadframe 8 can be held in the end area 19 in a holding rail 7. In Figure 20 also shows the connecting webs 16 which connect the sections 10, 10' of the leadframe 8 during manufacture.

[0122] Since the electronic components 5 of the driver 4 are usually arranged on the leadframe 8 before the leadframe is installed in the lamp, the Figure 20 does not represent a condition that normally occurs during the manufacture of the lamp, but is merely for illustrative purposes.

[0123] In general, "a", "an", etc. can be understood as a singular or a plural, in particular in the sense of "at least one" or "one or more", etc., as long as this is not explicitly excluded, e.g. by the expression "exactly one", etc.

[0124] A numerical value may also include the exact number stated as well as a usual tolerance range, as long as this is not explicitly excluded.

[0125] Where applicable, all individual features shown in the embodiments can be combined and / or exchanged. List of reference symbols

[0126] 1 Tubular piston 2 End cap 3 Connection pin 4 Electronic driver 5 Electronic components of the electronic driver 6 Circuit board of the electronic driver 7 Support rail 8 Leadframe 9 LED 9' LED 10 Section of the leadframe 10' Section of the leadframe 11 First track of the leadframe 12 Second track of the leadframe 13 Third track of the leadframe 14 U-shaped contact areas 15 Sheet 16 Connecting webs 17 Frame 18 Middle area of ​​the leadframe 19 First end area of ​​the leadframe 20 Second end area of ​​the leadframe 21 Further tracks of the leadframe 22 Recesses 23 Cable 24 Stabilization section 25 End face 26 Contact clip 27 Connection area of ​​the contact clip DDrectifier diodes C1Smoothing capacitor C2Capacitor R1Resistor R2Resistor ICIntegrated circuit

Claims

1. Lighting means with a translucent tubular bulb (1), at least one end cap (2) arranged at one end of the tubular bulb (1) and a light engine arranged in the tubular bulb (1), wherein the light engine has a lead frame (8) with an underside and with an upper side opposite the underside, on which a plurality of semiconductor lighting elements (9) are arranged, characterised in that the lead frame has at least two tracks parallel to one another, at least two of the tracks having a plurality of sections, the sections of a first track being arranged offset relative to the sections of a second track, so that these each overlap by half a section, the lead frame (8) having one or more projections (22), in particular deep-drawing sections, on the underside of the lead frame, i.e. on which no semiconductor lighting elements (9) are arranged, which are in the form of depressions on the upper side of the lead frame, and wherein the lead frame (8) is provided with an adhesive in the region of the projections (22), wherein the lead frame (8) is attached to the inside of the tubular bulb (1) by means of the adhesive.

2. The lighting means according to claim 1, wherein the tubular bulb (1) is sealed in a gas-tight manner.

3. The lighting means according to claim 2, wherein the tubular bulb (1) is filled with a filling gas, wherein the filling gas has a gas with high thermal conductivity.

4. The lighting means according to one of the preceding claims, further comprising an electronic driver (4) with a plurality of electronic components (5), wherein at least one of the electronic components (5) is arranged within the tubular bulb (1).

5. The lighting means according to claim 4, wherein at least one of the electronic components (5) is arranged on the lead frame (8).

6. The lighting means according to any one of claims 4-5, wherein the lead frame (8) comprises a centre region (18) on which the plurality of semiconductor lighting elements (9) is arranged, and at least one end region (19, 20) on which at least one of the electronic components (5) of the electronic driver (4) is arranged.

7. The lighting means according to claim 6, wherein the width of the lead frame (8) in at least one end region (19, 20) is greater than the width of the lead frame (8) in the centre region (18).

8. The lighting means according to one of claims 4-5, wherein the width of the lead frame (8) is variable over its length.

9. The lighting means according to any one of claims 4-8, wherein the electronic driver (4) is a linear driver.

10. The lighting means according to one of the preceding claims, wherein the tubular bulb (1) is at least partially provided with a filling material_at least on the inside of the tubular bulb (1) and / or in the region of at least one end cap (2).

11. The lighting means according to one of claims 4-10, wherein the electronic driver (4) comprises a printed circuit board (6) on which at least one of the electronic components (5) is arranged, wherein the printed circuit board (6) is connected to the lead frame (8) via at least one electrically conductive connecting element.

12. The lighting means according to claim 11, wherein the lead frame has a bent-over section (14) which serves as a connecting element.

13. The lighting means according to one of the preceding claims, wherein the light engine further comprises an electrically conductive means, in particular a cable, which extends from a first end of the lead frame (8) or a printed circuit board (6) arranged at the first end of the lead frame (8) to a second end of the lead frame (8) or a printed circuit board arranged at the second end of the lead frame (8).

14. The lighting means according to one of the preceding claims, wherein the light engine comprises one or more stabilising sections made of an insulating material which are introduced locally, preferably in the form of points and / or lines, into intermediate spaces of the lead frame in order to fasten sections of the lead frame to one another and preferably to space them apart from one another.