Single-ended discharge lamp

Abstract: The invention relates to a single-ended discharge lamp (1) having an electric circuitry placed in its cap member (5), which discharge lamp (1) comprises a discharge tube (2) filled with additive and gas, sealed in a gas-tight manner and provided with electrodes (3) as well as a cap member (5) providing for the operation of the discharge tube (2) and incorporating the electric circuitry mounted on a printed-circuit board (PCB) (6) where the cap member (5) is made in a way suitable both for mechanical and electrical connection to a lampholder, and for mechanically fixing the discharge tube (2) and connecting the output terminals of the circuitry with the electrode inleads of the discharge tube, furthermore the terminals of the circuitry are fixed on the PCB(6) and are electrically connected with the electrode inleads (4,41) of the discharge tube (2) by means of mechanical connector components (7,17,27) where the mechanical connector component (7,17,27) is one contiguous metal part. The essential feature of the solution according to the invention is the mechanical connector component (7,17,27) consists of a base part (8,18, 28) and a connection part (9,19,29) of which the base part (8,18, 28) is embedded in the PCB (6) and the electrode inlead (4) is connected to the connection part (9,19,29), furthermore the base part (8,18, 28) is fixed on the PCB (6) and is electrically connected with the corresponding output terminal of the circuitry, and the connection part (9,19,29) is formed as a cavity and the electrode inlead (4) intrudes into this cavity (10,20,30), and the electrode inlead (4) is mechanically fixed and simultaneously electrically connected to the wall of the cavity (10,20,30).

Description: The invention relates to a single-ended discharge lamp having a circuitry placed in its cap member, which discharge lamp comprises a discharge tube filled with additive and gas, sealed in a gas-tight manner and provided with electrodes as well as a cap member, which contains the circuitry providing for the operation of the discharge tube and mounted on a printed-circuit board (PCB) where the cap member is made in a way suitable both for mechanical and electrical connection to a lampholder, and for mechanically fixing the discharge tube and connecting the output terminals of the circuitry with the electrode inleads of the discharge tube, furthermore the terminals of the circuitry are fixed on the PCB and are electrically connected with the electrode inleads of the discharge tube by means of mechanical connector components where the mechanical connector component is one metal part. The solution according to the invention can be applied with advantage e.g. in case of all types of the so-called compact-design discharge lamps having the electronic ballast in the cap member, particularly in those having a PCB carrying the electronic circuitry assembled in a crowded and hard-to-access way. With the compact-design discharge lamps, several solutions are known for connecting the electrode inleads of the discharge tube with the output terminals of the corresponding operating circuitry. When choosing the type of solution for performing the electrical connection, it is a fundamental consideration that it is preferable to avoid using soldered or welded joints since in case of a PCB with high density of parts this would make them difficult to access and the operation of assembling would be troublesome to be automated. In addition, the process of soldering or welding would exert a heat load that adversely affects the electronic circuitry. Furthermore, in case metals that can be soldered less readily, solder materials of higher melting points would also be needed, which, in addition to the fact that would cause heat loads of intolerable extent, would necessitate the use of some special flux material that would release vapors detrimental to health. Moreover, the flux material that has spilt would have to be removed later - an activity making the manufacturing process troublesome. Those explained in the preceding make it obvious that mechanical joint is the only solution deserving to be dealt with. Such a mechanical joint, i.e. a discharge lamp having mechanical connector components is described, e.g. in German Patent Specification No. DE 34 39 137. In this solution a contact pin is fixed in a contact holder part embedded in the electronic circuitry PCB of a compact fluorescent lamp, the other end of said contact pin is - in order to make electrical contact - pressed, together with the electrode inlead of the discharge tube, into an accepting portion formed in the plastic cap member of the compact fluorescent lamp. The electrode inlead and the contact pin are clamped one to another by the resilient force of the plastic side wall of the hole. It is known that plastic materials that can be used in mass products have poorer elastic properties than metals, and the elasticity of plastic materials even decreases as time elapses. This means that the solution according to the Patent mentioned is unable to provide a sufficiently reliable contact between the electrode inleads and the output terminals of the electronic circuitry. EP-A-349083 discloses a similar lamp where the base part of the mechanical connector component holds the printed circuit board with clamping fit and the connection part receives the electrode inlead in a slot formed between two coplanar tonques. When choosing the type of solution for the mechanical joint the material of the electrode inlead of the discharge tube should be considered, both in respect of its mechanical properties and its suitability for making electrical contact. The objective of our invention was to provide a solution, by means of which the disadvantage mentioned can be eliminated and, at the same time can also be used in discharge lamps having electrode inleads made from materials - i.e. not only copper but e.g. nickel-plated iron-nickel alloy - with which it is difficult to make electrical contact, and which solution enables the automation of assembling. Based on those we have recognized, the objective set can be achieved by developing a discharge lamp that comprises appropriately chosen mechanical connector components, the base part of which mechanical connector component is embedded into the PCB of the circuitry and is connected with the output terminals of the circuitry, and its connection part is hollow, Into which cavity the electrode inlead intrudes to be connected mechanically to the wall of the cavity. In accordance with this our invention relates to a single-ended discharge lamp according to claim 1. In a preferred embodiment of the discharge lamp according to the invention the electrode inlead and the connector part are formed to make a deformation joint, i.e. to have a shape that mechanically fixes the electrode inlead to the wall of the cavity. In this case the connection part of the mechanical connector component preferably has a cylindrical shape and its cavity is a blind hole, in which the electrode inlead is placed in the direction of the axis of the mechanical connector component, and the electrode inlead is mechanically fixed in the blind hole by means of an indentation made in a direction perpendicular to the axis, which indentation causes a permanent deformation on the wall of the blind hole and on the electrode inlead resulting in a permanent joint. In another preferred embodiment of the discharge lamp according to the invention the connection part of the mechanical connector component is resilient and the electrode inlead is fixed to it by means of its resilient force. Joints of this type are releasable by exerting sufficient force against the resilient force. In this case the mechanical connector component can be made e.g. in the way that its connection part is formed by resilient pieces of plate and the electrode inlead is placed - perpendicularly to the axis of the mechanical connector component - in a slot-like cavity formed by the base plate and a tongue part cut and bent out from the middle portion of the base plate. Furthermore, an accepting portion is formed in at least one of the resilient pieces of plate, and the electrode inlead is forced to snap into this accepting portion to be fixed in it. The mechanical connector component can also be formed in the way, e.g. that its connection part is represented by a tube with a slot along its generatrix, which tube is resilient perpendicularly to the slot where the cavity of the connection part is formed by the hollow of the tube and by the slot, and the electrode inlead is placed in the slot in a direction perpendicular to the axis of the mechanical connector component. Such a solution is especially advantageous in the case of electrode inleads with which it is difficult to make electrical contact since during manufacturing, on introducing the electrode inlead into the slot, the surface of the electrode inlead will be scratched resulting in better electrical contact. With all embodiments of the discharge lamp, in order to make manufacturing easier it is practical to shape the mechanical connector component in the way that the connection part broadens at the place where the electrode inlead is inserted. Hereinafter our invention will be illustrated in more details by means of examples using its embodiments. Fig. 1: An example of one embodiment of the discharge lamp according to the invention. Fig. 2: Detail of another embodiment of the discharge lamp according to the invention. Fig. 3: Section A-A of the detail according to Fig. 2. Fig. 4: Detail of a third embodiment of the discharge lamp according to the invention. Fig. 5: Section B-B of the detail according to Fig. 4. In case of the discharge lamp 1 shown in Fig. 1 being a compact fluorescent lamp in our example, the discharge tube 2 is mechanically supported by the upper portion of the cap member 5 that has a threaded end portion and is suitable for connection to the mains, the electrode inlead 4 of one of the electrodes 3 of the discharge tube 2 is inserted into the cavity 10 of the cylindrical connection part 9 of the mechanical connector component 7 embedded in the PCB 6 fixed vertically in the cap member 5, and is fixed in the cavity 10 by means of the deformation joint 11. The cavity 10 is a blind hole. The mechanical connector component 7, which can be made e.g. from copper, is embedded - preferably by means of close fit - into the hole of the PCB 6 caught by its base part 8, and somewhat protrudes from the PCB 6 at the other end of the hole where it is soldered and thereby electrically connected with the corresponding output terminal of the circuitry placed on the PCB 6. The deformation joint 11 can be formed e.g. by making an indentation in a direction perpendicular to the axis 16 of the mechanical connector component 7 resulting in a permanent deformation of the mechanical connector component 7. For connecting the electrode inleads 4' (and all further inleads that are not shown in the Fig.), another mechanical connector component also embedded in the PCB 6 is used. In case of the embodiment of the discharge lamp, details of which are shown in Figs. 2 and 3, the electrode inlead 4 of one of the electrodes 3 of the discharge tube 2 is placed in a slot-like cavity 20 formed at the resilient connection part 19 of the mechanical connector component 17. The connection part 19 of the mechanical connector component 17 that can be made e.g. from beryllium bronze, is formed by resilient pieces of plate in the way that the electrode inlead 4 is inserted - in a direction perpendicular to the axis 26 of the mechanical connector component 17 - into the slot-like cavity 20 formed by the tongue portion 13 cut and bent out from the middle portion of the base plate 12 and by the base plate 12. In at least one of the resilient pieces of plate, e.g. in the base plate 12 an accepting portion 21 is formed, in which the electrode inlead 4 having forced to snap into, remains in a fixed position. The mechanical connector component 17 is embedded and soldered caught by its base part 18, in the PCB 6 placed in the cap member 5. In case of the discharge lamp, details of which are shown in Figs. 4 and 5, the electrode inlead 4 of the electrode 3 of the discharge tube 2 is placed in the cavity 30 of the connection part 29 of the mechanical connector component 27 that can be made e.g. from beryllium bronze. The connection part 29 is represented by a tube having a slot 24 along its generatrix and being resilient in a direction perpendicular to the slot 24 where the cavity 30 of the connection part 29 is formed by the hollow portion 25 of the tube and by the slot 24, and the electrode inlead 4 is placed in the slot 24 in a direction perpendicular to the axis 36 of the mechanical connector component 27, and in order to ensure that fixing is safe, the electrode inlead 4 preferably intrudes also in the hollow portion 25 of the tube. The electrode inlead 4 is kept in the slot 24 by the resilient tube wall, by clamping the inlead 4 from two opposite sides. The mechanical connector component 27 is, caught by its base part 28, embedded and soldered in the PCB 6 placed in the cap member 5. In the examples for our embodiments, the electrode inleads can be made e.g. from copper, but also from a material - such as nickel-plated iron-nickel alloy - with which it is more difficult to make electrical contact. The connection part of the mechanical connector component is preferably broadened at the places where the electrode inleads are inserted. The scope of protection for our invention allows the discharge lamp according to our invention to be made in several different embodiments and, in accordance with this our invention is not intended to be limited to the examples shown beforehand. List of references 1: Discharge lamp 2: Discharge tube 3: Electrode 4: Electrode inlead 4': Electrode inlead 5: Cap member 6: PCB 7: Mechanical connector component 8: Base part 9: Connection part 10: Cavity 11: Deformation joint 12: Base plate 13: Tongue portion 16: Axis 17: Mechanical connector component 18: Base part 19: Connection part 20: Cavity 21: Accepting portion 24: Slot 25: Hollow portion of tube 26: Axis 27: Mechanical connector component 28: Base part 29: Connection part 30: Cavity 36: Axis

Claims: Single-ended discharge lamp (1) having a circuitry placed in its cap member (5), which discharge lamp (1) comprises a discharge tube (2) filled with additive and gas, sealed in a gas-tight manner and provided with electrodes (3) as well as a cap member (5), which contains the circuitry providing for the operation of the discharge tube (2) mounted on a printed-circuit board (6) where the cap member (5) is made in away suitable both for mechanical and electrical connection to a lampholder and for mechanically fixing the discharge tube (2) and connecting the output terminals of the circuitry with the electrode inleads (4,4') of the discharge tube (2), furthermore the terminals of the circuitry being fixed on the printed-circuit board (6) and electrically connected with the electrode inleads (4,4') of the discharge tube (2) by means of mechanical connector components (7,17,27), where each mechanical connector component (7,17,27) is one metal part comprising a base part (8,18,28) fixed on the printed-circuit board (6) and electrically connected with the corresponding output terminal of the circuitry and a connection part (9,19,29) to which the respective electrode inlead (4) is connected characterized in that the base part (8,18,28) is embedded in the printed-circuit board (6) and in that the connection part (9,19,29) is formed to have a cavity (10,20,30) wherein the electrode inlead (4) intrudes and is mechanically fixed and simultaneously electrically connected to the wall of the cavity (10,20,30). Discharge lamp according to Claim 1 characterized in that the electrode inlead (4) is mechanically fixed to the wall of the cavity (10) by means of a deformation joint (11) made on the electrode inlead (4) and on the connection part (9). Discharge lamp according to Claim 2 characterized in that the connection part (9) of the mechanical connector component (7) is cylindrical in shape and the cavity (10) therein is a blind hole, in which the electrode inlead (4) is placed in the direction of the axis (16) of the mechanical connector component (7), and the electrode inlead (4) is mechanically fixed in the blind hole by means of an indentation made in a direction perpendicular to the axis (16). Discharge lamp according to Claim 1 characterized in that the connection part (19) is resilient and the electrode inlead (4) is mechanically fixed to the connection part (19) by its resilient force. Discharge lamp according to Claim 4 characterized in that the connection part (19) of the mechanical connector component (17) is formed by resilient pieces of plate in the way that the electrode inlead (4) is inserted - in a direction perpendicular to the axis (26) of the mechanical connector component (17) - into the slot-like cavity (20) formed by the tongue portion (13) cut and bent out from the middle portion of the base plate (12) and by the base plate (12), and in at least one of the resilient pieces, an accepting portion (21) is formed, in which the electrode inlead (4) having forced to snap into, remains in a fixed position. Discharge lamp according to Claim 4 characterized in that the connection part (29) of the mechanical connector component (27) is represented by a tube having a slot (24) along its generatrix and being resilient in a direction perpendicular to the slot (24) where the cavity (30) of the connection part (29) is formed by the hollow portion (25) of the tube and by the slot (24), and the electrode inlead (4) is placed in the slot (24) in a direction perpendicular to the axis (36) of the mechanical connector component (27). Discharge lamp according to Claims 1 through 6 characterized in that the connection part (29) of the mechanical connector component (27) is formed to have a broadening at the place where the electrode inlead (4) is inserted.

Inventors: FUELOEP JOZSEF, HARSA JIM, PAPP FERENC, TOEKES JOZSEF, FUELOEP, JOZSEF, HARSA, JIM, PAPP, FERENC, TOEKES, JOZSEF, Fülöp, Jozsef, Tökes, Jozsef
Applicants: TUNGSRAM RESZVENYTARSASAG
Application year: 1995
Main classification: H01J61
IPC codes: H01J5, H01J61