Electrical connection of PCBs by clamp spring connector

Abstract

A light fixture includes a light-emitting diode chip, a driver electronic, a first circuit board and a second circuit board, wherein the light-emitting diode chip is mounted on one of the two circuit boards and the driver electronic is mounted on the other one of the two circuit boards and a first conductive track of the first circuit board and a second conductive track of the second circuit board are connected electrically to one another with a spring contact.

Claims

1. A light fixture comprising: a light emitting diode chip; a driver electronic; and a first circuit board and a second circuit board; wherein the light emitting diode chip is mounted on one of the two circuit boards and the driver electronic is mounted on the other one of the two circuit boards; and wherein a first conductive track of the first circuit board and a second conductive track of the second circuit board are electrically connected to one another by means of a spring contact, wherein the spring contact includes two clamping arms connected by a central segment and each clamping arm includes a protrusion that extends into a free space between the clamping arms, wherein the spring contact contacts the first conductive track of the first circuit board and the spring contact contacts the second conductive track of the second circuit board to form an electrical connection between the first conductive track and the second conductive track, wherein the first conductive track of the first circuit board faces the second conductive track of the second circuit board, and wherein the protrusions of the clamping arms are offset from one another along a vertical z-axis.

2. The light fixture according to claim 1, wherein the spring contact is fastened on the second circuit board by means of at least one of a soldered connection and a clamp connection.

3. The light fixture according to claim 1, wherein the dimensions of the spring contact are such that, in a contact region of the first circuit board and in a contact region of the second circuit board, the spring contact exerts a residual spring force on the first circuit board or the second circuit board.

4. The light fixture according to claim 1, wherein a spring deflection of the spring contact corresponds to at least a thickness of the first circuit board.

5. The light fixture according to claim 1, wherein the spring contact contacts the second conductive track of the second circuit board in a planar manner.

6. The light fixture according to claim 1, wherein the spring contact extends in a curved manner in at least one end region in such a way that an end edge of the spring contact projects away from at least one of the first circuit board and the second circuit board.

7. The light fixture according to claim 6, wherein a bend of the spring contact touches at least one of the first conductive track of the first circuit board in a contact region and the second circuit board in a contact region.

8. The light fixture according to claim 1, wherein the second circuit board is clamped between the two clamping arms.

9. The light fixture of claim 8, wherein the second circuit board has indentations that the protrusions of the spring contact engage.

10. The light fixture of claim 9, wherein the indentations of the second circuit board are positioned on opposing sides of the second circuit board.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred further embodiments of the invention are explained in greater detail by the following description of the drawings.

(2) FIGS. 1A, 1B, 2A and 2B show exemplary embodiments of a light fixture described here as well as a spring contact described here.

(3) FIGS. 3A, 3B, 3C and 3D show exemplary embodiments of a spring contact described here.

(4) FIGS. 4A, 4B, 4C, 5A, 5B, 5C and 5D show exemplary embodiments of a light fixture described here as well as a spring contact described here.

(5) FIG. 6 shows an exemplary embodiment of a spring contact described here.

(6) FIGS. 7A, 7B, 7C, 8A, 8B, and 8C show exemplary embodiments of a light fixture described here as well as a spring contact described here.

(7) FIGS. 9A, 9B, 9C and 9D show exemplary embodiments of an alternative light fixture as well as an alternative contact.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

(8) The light fixture described here, as well as the spring contact described here, are explained in greater detail below with reference to exemplary embodiments and the associated drawings. In this case, elements which are the same, of the same kind, similar or equivalent are provided with the same reference numerals. Repeated description of some of these elements is omitted in order to avoid redundancies.

(9) The drawings and the size ratios of the elements illustrated in the drawings elements should not be regarded as drawn to scale relative to one another. On the contrary, individual elements may be shown as excessively large for better illustration and/or to aid understanding.

(10) An exemplary embodiment of a light fixture 1, as well as a spring contact 30, is described here in greater detail with reference to the schematic sectional representation in FIG. 1A.

(11) The light fixture 1 in the present case is a retrofit light fixture as a replacement for a fluorescent tube. The light fixture 1 comprises two driver modules 4 and a light module 2. However, unlike the illustration in FIG. 1A, the light fixture 1 can also have only one driver module 4 or more than two driver modules 4. The driver modules 4 and the light module 2 are introduced into a tube 11, which may be a light-permeable glass and/or plastic tube. The ends of the tube 11 are in each case introduced into a housing 12 with contact pins 13. The housing 12 serves as the electrical contact and the mechanical mounting of the light fixture 11 in a lamp socket.

(12) The light module 2 has a plurality of light-emitting diode chips 22, which are mounted on a mounting surface 21a of a common first circuit board 21. The first circuit board 21 is retained by means of first retainers 23 in the tube 11 of the light fixture 1.

(13) The driver module 4 has in each case a driver electronic 42, which are mounted on a mounting surface 41a of a common second circuit board 41. The first circuit board 21 and the second circuit board 41 are, in particular, different from one another. The second circuit board 41 is retained by means of second retainers 43 in the tube 11 of the light fixture 1.

(14) For example, the mounting surface 21a of the first circuit board 21 has the first conductive tracks 211 and the base surface 41c of the second circuit board 41 has the second conductive tracks 411.

(15) The driver electronic 42 of the driver module 4 comprises electronic components which serve for electrical activation of the light-emitting diode chips 22 of the light-emitting diode module 2. In particular, the driver electronic 42 can convert a voltage provided on the contact pins 13 or a provided current into an operating voltage or an operating current of the light-emitting diode module 2.

(16) The first circuit board 21 and the second circuit board 41 (or the second circuit boards 41) in each case have first conductive tracks 211 or second conductive tracks 411, by means of which the light-emitting diode chips 22 or the electronic components of the driver electronic 42 are electrically connected to one another (not shown in FIG. 1A). The first conductive tracks 211 of the first circuit board 21 are electrically connected to the second conductive tracks 411 of the second circuit board 41 via a spring contact 30.

(17) In the exemplary embodiment of FIG. 1A, the spring contact 30 is mounted on a base surface 41c of the second circuit board 41 opposite the mounting surface 41a of the second circuit board 41, wherein the base surface 41c of the second circuit board 41 faces the first circuit board 21. However, it is alternatively or additionally possible that the spring contact 30 is mounted on the mounting surface 41a of the second circuit board 41.

(18) A further exemplary embodiment of a light fixture 1, as well as a spring contact 30, is described here in greater detail with reference to the schematic sectional representation in FIG. 1B. In contrast to the exemplary embodiment of FIG. 1A, the spring contact 30 is clamped on the second circuit board 41 and touches the second circuit board 41 both in its mounting surface 41a and also in its ground surface 41c. The first retainer 23 and the second retainer 43 are also connected to one another in the exemplary embodiment.

(19) Between one of the electronic component 421 of the driver electronic 42 (in the present case the electronic component 421 is a capacitor) insulation 44 is provided, which electrically insulates the electronic component 421 from the spring contact 30. In general, due to the use of insulation 44 between a part of the driver electronic 42 and the spring contact 30, a short-circuit can be avoided and the size of the driver electronic 42, and consequently of the light fixture 1, can be further reduced.

(20) An exemplary embodiment of a light fixture 1, as well as a spring contact 30, is described here in greater detail with reference to the schematic representations in FIGS. 2A and 2B. In this case an enlarged region of a light fixture 1, according to the exemplary embodiment of FIG. 1A, is shown for general explanation of the mode of operation of the spring contact 30. FIG. 2A shows the driver module 4, the light module 2 and the spring contact 30 before they are mechanically connected, while FIG. 2B shows the driver module 4, the light module 2 and the spring contact 30 in the mechanically connected state.

(21) In FIG. 2A the spring contact 30 is present in the unstressed state. The spring contact 30 is fastened to the second circuit board 41. Purely by way of example, in the illustrated exemplary embodiment the spring contact 30 is fastened to the base surface 41c of the second circuit board 41. In the unstressed state the spring contact 30 extends beyond the first circuit board 21 in a vertical direction z, and when the spring contact 30 is in the stressed state it is arranged between the first circuit board 21 and the second circuit board 41. Thus the extension of the spring contact 30 in the vertical direction z is greater than a distance between the first circuit board 21 and the second circuit board 41 in the vertical direction z.

(22) For connection of the driver module 4 and the light module 2, the driver module 4 is preferably slid in a lateral direction (i.e. perpendicular to the vertical direction z) over the first circuit board 21, so that the spring contact 30 is compressed by the first circuit board 21 and the second circuit board 41. The lateral movement can be simplified by means of a bend 31 in an end region 303 close to a first end edge 34 of the spring contact 30 facing the first circuit board 21. Due to the bend 31, it is not the (sharp) first end edge 34 but the (smooth) bend 31 that comes into contact with the first circuit board 21, so that friction is reduced and/or scratches are avoided.

(23) In FIG. 2B, the spring contact 30 is present in the tensioned state. The spring contact 30 touches the first circuit board 21, or the first conductive tracks 211 of the first circuit board 21, in a contact region 210 and contacts the first conductive tracks 211 in this way. In particular, the bend 31 is in the contact region 210 and is in direct contact with the first conductive tracks 211.

(24) Exemplary embodiments of a spring contact 30 described here are explained in greater detail with reference to the schematic illustrations in FIGS. 3A, 3B, 3C and 3D. Different geometric configurations of a spring contact 30 are shown. Each of the exemplary spring contacts 30 shown in FIGS. 3A to 3D have a connection region 300 for connection to the second circuit board 41, a spring arm 301 as well as a spring segment 33 (which is notably curved) connecting the connection region 300 and the spring arm 301. Each spring contact 30 is completed by a first end edge 34 which is part of the spring arm 301, and a second end edge 35 which is part of the connection region 300.

(25) The spring contact 30 of FIG. 3A has the shape of a V (tilted by 90). The connection region 300 is straight and has no bends 31 in an end region 303 close to the second end edge 35. The connection region 300 is suitable, for example, for a soldered connection to a second circuit board 41. The spring arm 301 has the bend 31 in an end region 303, so that the first end edge 34 is curved upwards.

(26) The spring contact 30 of FIGS. 3B and 3C has a S-shaped configuration. The connection region 300 is connected by means of two spring segments 33 to the spring arm 301. While FIG. 3B shows the spring contact 30 in the not tensioned state, the spring contact 30 in FIG. 3C is tensioned by a spring deflection f, so that the spring contact 30 is compressed in the vertical direction z. The spring deflection f is generally selected so that the spring contact 30 is not over stretched, which is where a complete regression of the spring contact 30 is no longer possible. In particular, the spring deflection f can be adapted by means of the shape of the spring contact 30 and/or the material of the spring contact 30.

(27) The spring contact 30 of FIG. 3D is designed as a clamping contact. The connection region 300 of the spring contact 30 has two clamping arms 36 which are connected by means of a central segment 302. A protrusion 37 which extends into a free space between the two clamping arms 36 is introduced into each of the clamping arms 36. In the end regions 303 of the spring contact 30, the spring contact comprises bends 31. The first end edge 34 and the second end edge 35 of the spring contact 30 are bent in the same direction by the bends 31.

(28) Further exemplary embodiments of a light fixture 1, as well as a spring contact 30, is described here in greater detail with reference to the schematic representations in FIGS. 4A, 4B and 4C. FIGS. 4A to 4C each show a spring contact 30 which is connected by means of a clamp connection to the second circuit board 41, wherein the second circuit board 41 is clamped between the two clamping arms 36 of the spring contact 30 (see also FIG. 3D). On the second circuit board 41 the spring contact 30 touches the base surface 41c in a contact region 410, and the spring contact 30 touches on the first circuit board 21 the mounting surface 21a in a contact region 210. The contact region 410 of the second circuit board 41 preferably comprises the second conductive tracks 411, so that in the contact region 410 an electrical connection between the spring contact 30 and the second conductive tracks 411 takes place. Furthermore, the spring contact 30 touches the mounting surface 41a of the second circuit board 41 in a contact region 322.

(29) In FIG. 4A, the spring contact 30 is illustrated both in the tensioned state (solid line) and also in the not tensioned state (dashed line), that is to say in the non-connected state. From the tension of the spring contact 30, this spring contact is compressed by spring deflection f. The spring deflection f is preferably greater than a thickness d of the first circuit board 21, in order to generate, in particular, a high residual spring force on the contact region 210 of the first circuit board 21.

(30) FIG. 4B shows a schematic sketch of the distribution of force in the system consisting of first circuit board 21, second circuit board 41 and spring contact 30. A first force F1 acts on the contact region 210 of the first circuit board 21 (this force corresponds to the residual spring force or restoring force of the spring contact 30 in said contact region 210). A second force F2 acts on the contact region 410 of the second circuit board 41 (this force corresponds to the residual spring force or restoring force of the spring contact 30 in said contact region 410). A third force F3 acts on an edge region 323 of the second circuit board 41. The edge region 323 is, in particular, the region of the second circuit board 41 in which the clamping arm 36, while touching the mounting surface 41a, merges into the central segment 30 that connects the two clamping arms 36. The spacing between the edge region 323 and the contact region 210 of the first circuit board 21 corresponds to a first length L1, and the spacing between the edge region 323 and the contact region 420 of the second circuit board 41 corresponds to a second length L2.

(31) The dimensions of spring contact 30, or the dimensions of the first length L1 and the second length L2, is preferably designed in such a way that the forces cancel each other out, that is to say F1+F2+F3=0 (F1, F2 and F3 are, in each case, the force vectors of the first force, the second force and the third force). For an example of the dimension for L1, assume L2 of the spring contact has a second force F2 is twice as great as the first force F1. In this case, the first length L1 can be twice as great as the second length L2. For example, the first length L1 is 9 mm and the second length L2 is 4.5 mm. For example, the first force F1 for a single spring contact 30 is at least 4 N and at most 8 N.

(32) The spring contact 30 of the exemplary embodiments of FIGS. 4A and 4B in each case have a bend 31 that touches the first circuit board 21 in the contact region 210 thereof. In contrast to this, the exemplary embodiment of FIG. 4C has the first end edge 34 of the spring contact 30 directly touch the first circuit board 21, or the first conductive tracks 211 of the first circuit board 21. The principles described in connection with the preceding FIGS. 4A and 4B also apply to such a spring contact 30.

(33) An exemplary embodiment of a light fixture 1, as well as a spring contact 30, is described here in greater detail with reference to the schematic representations in FIGS. 5A, 5B, 5C and 5D. The spring contact 30 is formed as in FIG. 3D.

(34) For improvement of the mechanical connection of the spring contact 30 to the second circuit board 41, the second circuit board 41 has indentations 46 that the protrusions 37 of the spring contact 30 engage (FIGS. 5A and 5B). For production of the connection, the spring contact 30 is slid over the second circuit board 41. The protrusions 37 can then engage in the indentations 46 and the spring contact 30 is fixed to the second circuit board 41 (FIGS. 5C and 5D).

(35) FIG. 6 shows a simulated stress distribution along a spring contact 30 of FIG. 3D introduced into a light fixture 1 (cf. also FIGS. 4A, 4B, 5A to 5D). This drawing shows first stress regions 601, second stress regions 602, third stress regions 603, fourth stress regions 604 and fifth stress regions 605, wherein the stress c (in particular the von-Mises stress) decreases as the numbers increase (see stress scale). A high stress is only to be measured in a small region on the spring segment 33. In this region the restoring force can act indirectly on the spring arm 301. The rest of the spring contact 30 only has little tension.

(36) The first stress region 601 can, for example, correspond to a stress of at least 800 N/mm.sup.2 and at most 960 N/mm.sup.2. The second stress region 602 can, for example, correspond to a stress of at least 650 N/mm.sup.2 and at most 800 N/mm.sup.2. The third stress region 603 can, for example, correspond to a stress of at least 300 N/mm.sup.2 and at most 650 N/mm.sup.2. The fourth stress region 605 can, for example, correspond to a stress of at least 100 N/mm.sup.2 and at most 300 N/mm.sup.2. The fourth stress region 605 can, for example, correspond to a stress of at least 0 N/mm.sup.2 and at most 100 N/mm.sup.2.

(37) Exemplary embodiments of a light fixture 1, as well as a spring contact 30, are described here in greater detail with reference to the schematic representations in FIGS. 7A, 7B and 7C. These show possible configurations of the first conductive tracks 211 and/or the second conductive tracks 411 in the region of the contact with the spring contact 30. FIGS. 7A and 7B each show plan views of the first circuit board 21 and the second circuit board 41, in each case from different directions. FIG. 7C shows an enlargement of the second conductive tracks 411 of FIG. 7A.

(38) The second circuit board 41 has the second conductive tracks 411 on its base surface 41c. The spring contact 30 can, for example, be soldered on the second conductive tracks 411.

(39) For this purpose, an end region 300 of the spring contact 30 can be forked. The mounting surface 21a of the first circuit board 21 is turned towards the base surface 41c of the second circuit board 41. The mounting surface 21a has first conductive tracks 211. The first conductive tracks 211 and the second conductive tracks 411 can be solder pads which, however, are not soldered to the spring contact 30, like in the case of the first conductive tracks 211. Thus, an already existing architecture of the circuit boards 21, 41 can be used.

(40) Exemplary embodiments of a light fixture 1, are explained in greater detail with reference to the schematic illustrations in FIGS. 8A, 8B and 8C. FIG. 8A again shows the spring contact 30 connected to the second circuit board 41 via a clamp connection. The spring contact 30 contacts the first conductive tracks 211 of the first circuit board 21 in a contact region 210. The first conductive tracks 211 can be mounted as thin strips, formed in particular with tin, on a conductive track, which is formed in particular with copper (FIG. 8B). It is also possible that the first conductive tracks 211 are provided in the form of a completely tin-plated and/or gold-plated copper conductive track (FIG. 8C). In particular, tin plating can significantly increase the service life of the first conductive tracks 211, which the spring contact 30 slides over during assembly.

(41) Exemplary embodiments of an alternative light fixture 1, as well as an alternative contact 71, 72, 81, 82, are explained in greater detail with reference to the schematic representations in FIGS. 9A, 9B, 9C and 9D.

(42) The FIG. 9A shows an alternative light fixture 1, wherein the first circuit board 21 (contained in the tube 11) and the second circuit board 41 (contained in the housing 12) are connected by means of cables 72 which are soldered to the first circuit board 21 by means of solder points 71. However, such a soldered connection is not suitable for automation of the mounting.

(43) FIGS. 9B to 9D in each case show a first circuit board 21, which can be electrically connected to a second circuit board 41 by means of plug connectors 81, 82. The plug connectors in each case have a socket component 81 and an opposing plug component 82. The socket component 81 has sockets 811 to receive plugs 821 of the plug component 82. A socket contact 812 of the socket component 81 can be electrically connected by means of surface mounting (FIG. 9B) or by means of plug-in mounting (FIGS. 9C and 9D) to the second circuit board 41. Furthermore, a plug contact 822 of the plug component 82 can be electrically connected by means of surface mounting (FIG. 9B) or by means of pressure plug-in mounting (FIGS. 9C and 9D) to the first circuit board 21. The illustrated plug connectors 81, 82 enable a mechanical, non-destructive releasable connection, but here too an automated mounting is only possible to a limited extent and, moreover, the plug connectors 81, 82 are expensive to obtain (more than 10 times the price of the spring contact 30).

(44) The invention is not limited to these embodiments by the description with reference to the exemplary embodiments. On the contrary, the invention encompasses each new feature as well as any combination of features. In particular, the invention includes any combination of features in the claims even if this feature, or this combination itself, is not explicitly given in the claims or the exemplary embodiments.

LIST OF REFERENCES

(45) 1 light fixture 1 alternative light fixture 11 tube 12 housing 13 contact pin 136 conductor 2 light module 21 first circuit board 21a mounting surface of the first circuit board 21c base surface of the first circuit board 210 contact region of the first circuit board 211 first conductive track 22 light emitting diode chip 23 first retainer 30 spring contact 300 connection region 301 spring arm 302 central segment 303 end region 322 contact region 323 edge region 31 bend 33 spring segment 34 first end edge 35 second end edge 36 clamping arm 37 protrusion 4 driver module 41 second circuit board 41a mounting surface of the second circuit board 41c base surface of the second circuit board 410 contact region of the second circuit board 411 second conductive track 42 driver electronic 421 electronic component 43 second retainer 44 insulation 46 indentation d thickness of the first circuit board f spring deflection L1 first length L2 second length F1 first force F2 second force F3 third force 601, . . . , 605 first, . . . , fifth stress region 71 solder point 72 cable 81 socket component 811 socket 812 socket contact 82 plug component 821 plug 822 plug contact z vertical direction