Two-part LED connection element

Abstract

Connection element for the electrical connection of an LED light source, - wherein the LED light source has a printed circuit board which is provided with contact fields for the electrical supply of the LED, - with a substantially ring-shaped frame which is intended to cover the printed circuit board and to mechanically hold it on an arrangement surface of a counter bearing, - with an outer ring and an inner ring arranged in the outer ring which together form the frame, - with a contact arrangement which is mounted in the frame and which serves for the electrical supply of the LED, - a connection contact in the outer ring for the connection of a connecting conductor, in particular without soldering, as the first part of the contact arrangement, - a supply contact in the inner ring for the electrical contacting of a contact field of the printed circuit board as the second part of the contact arrangement, wherein - the connection contact and the supply contact are connected to each other.

Description

[0001] Connection element for the electrical connection of an LED lamp, wherein the LED lamp has a circuit board which is provided with contact fields for the electrical supply of the LED, with a substantially ring-shaped frame which is provided to overhang the printed circuit board and to hold it mechanically on an arrangement surface of a counter-bearing, with a contact arrangement which is mounted in the frame and serves to supply the LED with electricity, with an outer ring which carries a connection contact for connecting a connection conductor as the first part of the contact arrangement, with a supply contact for making electrical contact with a contact field of the printed circuit board as the second part of the contact arrangement, wherein the connection contact and the supply contact are connected to one another.

[0002] LED connection elements are known, for example, from EP 2 083 489 A1. They serve to mechanically attach an LED light source—a circuit board with an LED arranged thereon—to a counter-support, primarily a heat sink. Furthermore, these LED connection elements provide a contact arrangement that serves, on the one hand, to connect connecting conductors and, on the other hand, to contact contact pads on the circuit board. In this way, the contact arrangement also serves to supply electricity to the LED light source. Such LED connection elements have the great advantage of combining both the mechanical fixation and the electrical contacting of the LED light source, thus simplifying the use of LED light sources in modern luminaires.

[0003] The applicant has published a newly developed LED connection element with priority application DE 20 2023 105 716 U1. This connection element is characterized by its two-part construction. An outer ring is designed to be fixed to a heat sink and precisely accommodate the LED circuit board within a mounting frame. An inner ring is inserted into the outer ring, which overlaps the circuit board and thus secures it in the connection element. Furthermore, the inner ring exerts a pressure force on the circuit board, pressing it against the heat sink to optimize heat transfer. This is preferably achieved using spring elements.

[0004] The spring-loaded arrangement of the inner ring within the outer ring also allows for unavoidable tolerances in the circuit board thickness to be compensated. The inner ring is thus positioned with a certain degree of tolerance in the light emission direction of the LED and in the vertical direction relative to the counter bearing or its mounting surface for the LED. For further details, please refer to DE 20 2023 105 716 U1.

[0005] The aforementioned publication discloses two different embodiments of the two-part connecting element. In a first embodiment, the inner ring is inserted vertically into the outer ring toward the counterbearing and then rotated relative to the outer ring. The inner ring is thus secured in the outer ring in a bayonet-type manner.

[0006] The second embodiment is limited to inserting the inner ring vertically into the outer ring, with locking projections of the inner ring being overlapped by locking springs of the outer ring.

[0007] WO 2012 / 030536 A2 discloses a connection element consisting of a ring into which a housing is inserted. This housing carries, among other things, the LED circuit board. A flexible printed circuit board is arranged within the housing, which serves as a supply contact and connects to a connection contact of the ring.

[0008] US 2016 / 0312984 A1, CN 106704904 A, WO 2015 / 008555 A1 and US 2013 / 0084748 A1 show connection elements with one-piece connection contacts

[0009] The object of the invention is to propose a contact arrangement which ensures the electrical supply of the LED lamp even with a two-part connection element.

[0010] The object of the invention is achieved by a connecting element with the features of claim 1, in particular with its characterizing features, according to which the connecting element comprises: an inner ring arranged in the outer ring, which together with the outer ring forms the frame, the supply contact carried by the inner ring, wherein the supply contact is equipped with a geometric pivot axis which is arranged parallel to the arrangement surface of the counter bearing and the supply contact is arranged in the inner ring so as to be pivotable about this pivot axis.

[0011] The invention utilizes the division of the connecting element into an outer ring and an inner ring to also separate the contact arrangement, which in the prior art is a single piece, into a connecting contact and a supply contact. The connecting contact located in the outer ring primarily serves to connect to the external connecting conductor and can therefore be precisely tailored to this purpose in terms of its geometry, metal alloy, and contact finish.

[0012] The supply contact located in the inner ring is primarily designed to contact the associated contact field of the circuit board in the correct position and can be designed in terms of its geometry, its contact forces and its contact finishing to create an optimal electrical transition from the supply contact to the contact field of the circuit board.

[0013] When the inner ring is inserted into the outer ring, this assembly process connects the connection contact and the supply contact to each other, thus establishing the electrical supply to the LED lamp.

[0014] The supply contact has a geometric pivot axis which is arranged parallel to the arrangement surface of the counter bearing, wherein the supply contact is arranged in the inner ring so as to be pivotable about this pivot axis.

[0015] The key advantage of this inventive feature is that the supply contact is arranged so that it can move around the pivot axis and thus oscillate. It is arranged on the inner ring in the manner of a balance beam or rocker. The pivot axis is—as described—aligned parallel to the mounting surface of the counter bearing or parallel to the surface of the circuit board on which the LED is mounted.

[0016] The pendulum suspension of the supply contact allows for even better compensation of the thickness tolerances of the circuit boards than if only the spring elasticity of the contact arms were used. Furthermore, the pendulum suspension of the supply contact also compensates for increased or decreased spring forces on the side of the contact leg of the supply contact resting on the contact pad of the circuit board by distributing the force between both contact legs. This ensures sufficient, but not excessive, contact pressure of the contact legs against their respective corresponding contact surfaces.

[0017] It is also provided that the connection contact forms a contact surface, the supply contact forms a mating contact surface and the contact surface and the mating contact surface lie directly against one another.

[0018] Particularly preferred is an embodiment in which the connection contact forms a contact arm which extends into a region of the frame covered by the inner ring and forms the contact surface for the supply contact in this region.

[0019] This design ensures a particularly simple connection between the connection contact and the supply contact, since the mutual contact surfaces face each other and are exposed when the inner ring is inserted into the outer ring, opposite to the light exit direction. Inserting the inner ring into the outer ring also means that the contact surface of the connection contact intended for connecting the supply contact is covered by the inner ring, thus ensuring the required contact protection.

[0020] Specifically, it is intended that the supply contact is designed as a contact bridge which spans the area between the contact surface of the connection contact and the contact field of the circuit board.

[0021] Specifically, it is provided that the supply contact has a first contact leg, which forms the mating contact surface for contacting the connection contact, and the supply contact has a second contact leg, which is intended to rest on the contact field of the printed circuit board.

[0022] The invention further proposes that the first contact leg is deflected in a spring-return elastic manner in the direction of the contact field of the connection contact and the second contact leg is deflected in a spring-return elastic manner in the direction of the contact field of the printed circuit board.

[0023] The spring-return elasticity of the supply contact's contact legs ensures that sufficient contact forces are maintained both between the terminal contact and the supply contact, and between the supply contact and the contact pad of the circuit board, to establish a secure electrical connection. Furthermore, the spring-return elasticity of the contact legs can also be helpful in compensating for circuit board thickness tolerances without compromise while maintaining consistent contact quality.

[0024] It is also possible for the pivot axis to be positioned off-center with respect to the distance between the contact surface of the connection contact and the contact field of the circuit board.

[0025] The off-center arrangement of the pivot axis can be used to fine-tune the contact pressure of the supply contact, both on the circuit board and on the terminal contact. In particular, the contact pressure can be increased or decreased by the off-center arrangement of the pivot axis toward the circuit board or toward the terminal contact. This makes it possible, for example, to address specific requirements for the coating of the contact surfaces and thus not only determine the optimal contact pressure for optimal electrical contact, but also ensure a wear-reducing distribution of the contact pressure.

[0026] Specifically, it is provided that the inner ring forms a retaining pin for arranging the supply contact, the supply contact forms a retaining opening for the retaining pin and the retaining pin passes through the retaining opening to anchor the supply contact.

[0027] Such a retaining pin is particularly easy to manufacture using the injection molding process. The supply contact is also particularly easy to mount on such a retaining pin. The retaining pin is aligned vertically to the mounting surface of the counter-bearing or parallel to the light emission direction of the LED. However, by appropriately designing the connection to the supply contact, this pin allows for a geometric pivot axis that is parallel to the mounting surface of the counter-bearing.

[0028] In order to ensure a defined movement of the supply contact about its pivot axis, it is provided that the inner ring forms at least one guide web, which rests against an edge of the supply contact and prevents rotation of the supply contact about the retaining pin.

[0029] The following description of an embodiment of the invention reveals further features and advantages. It shows: Figure 1 an exploded view of the connecting element according to the invention, Figure 2 a view from below of the inner ring of the connecting element after Figure 1 , Figure 3 a top view of the connecting element according to Figure 2 , Figure 4 a first sectional view according to section line AA in Figure 3 , Figure 5 a second sectional view according to section line AA in Figure 3 .

[0030] In the figures, a connecting element is designated overall by the reference number 10.

[0031] The connecting element 10 serves to connect an LED lamp 11 to the arrangement surface A ( Figures 4 and 5) of a heat sink (not shown). This arrangement surface A extends parallel to the underside of a printed circuit board 12, which carries an LED 13 and contact pads 14 on its upper side and is part of the illuminant 11.

[0032] The connection element 10 initially comprises an outer ring 15, the underside of which, facing away from the light exit direction L of the LED 13, also rests on the arrangement surface A of the counter-bearing (not shown). The outer ring 15 initially forms a frame 16 for receiving the circuit board 12, by means of which the circuit board 12 is held parallel to the arrangement surface A.

[0033] The outer ring 15 then carries connecting contacts 17, which are arranged in contact receptacles 18 of the outer ring 15. Each contact receptacle 18 is closed by a cover 19 on the upper side of the outer ring 15, so that the connecting contacts 17, as far as they are seated in the contact receptacle 18, are arranged in a manner protected from contact.

[0034] The connection element 10 then comprises an inner ring 20, which is inserted into a receiving space 21 formed by the outer ring 15. When assembled, the inner ring 20 overlaps the circuit board 12, but allows the light emission of the illuminant 11 through its central light exit opening 22, which surrounds the LED 13. The inner ring 20 also carries the supply contacts 23.

[0035] Each supply contact 23 has a first contact leg 24 and a second contact leg 25. Between the contact legs 24, 25, the supply contact 23 forms a holding opening 26.

[0036] Each connecting contact 17 has a contact arm 27. When the connecting contact 17 is seated in its associated contact receptacle 18, the contact arm 27 extends from the contact receptacle 18 and engages in the receiving space 21 formed by the outer ring 15 to accommodate the inner ring 20. In the exemplary embodiment, an insert contour 29 is formed in a base section 28 of the outer ring 15. This insert contour serves to accommodate the contact arm 27 emerging from the receiving space 21. The insert contour 29 is advantageous in every respect but is not absolutely necessary for the invention.

[0037] Each contact arm 27 forms a contact surface 30 pointing in the direction of the inner ring 20, which is intended to come into contact with a mating contact surface 31 of the first contact leg 24 of the supply contact 23.

[0038] Figure 2shows a view of the underside of the inner ring 20. On both sides of the light exit opening 22, retaining pins 32 are formed on the inner ring 20. Each retaining pin 32 is directed approximately parallel to the light exit direction L or perpendicular to the arrangement surface A of the counter bearing (not shown) and holds a supply contact 23. For this purpose, the respective retaining pin 32 extends through the retaining opening 26 of the supply contact 23. To prevent the supply contact 23 from slipping off the retaining pin 32, the retaining pin 32 is shaped into a mushroom head at its free end after the supply contact 23 has been inserted. Two guide webs 33 are formed on the inner ring 20 to the side of each supply contact. Two guide webs 33 each hold a supply contact 23 between them. In this way, the guide webs 33 prevent the supply contact from rotating about the longitudinal axis of the retaining pin 32.

[0039] The supply contact 23 is held on each retaining pin 32 with a certain amount of play, so that each supply contact 23 - guided by the guide bars 33 - can swing around a pivot axis S. As can be seen from Figure 2 As can be seen, the pivot axis S is parallel to the arrangement surface A for the circuit board 12, so that the supply contact 23 can swing in the manner of a seesaw or a balance beam.

[0040] Figure 3 shows a top view of the assembled connecting element 10 according to Figure 1Including LED light source 11. This shows how the inner ring 20 fits into the outer ring 15 and how the light exit opening 22 of the inner ring 20 surrounds the LED 13, allowing the light emitted by the LED 13 to exit unhindered. Also shown is how the covers 19 seal the contact receptacle 18 to the top of the connection element 10, to clarify the section line AA. This section line extends lengthwise through the supply contact 23.

[0041] Figure 4 shows a sectional view along section line AA in Figure 3 This illustration shows a sectional view along the longitudinal axis of the supply contact 23. Only a small section of the printed circuit board 12 is shown, namely the corner in which a contact field 14 is arranged.

[0042] How to Figure 4As can be seen, the illustrated connection contact 17 is seated in its contact receptacle 18, which is closed at the top with a cover 19. The contact arm 27 extends from the contact receptacle 18 into the receiving space 21 for the inner ring 20. It lies in the insert contour 29, which is formed by the base section 28 of the outer ring 15. It is clearly evident that the contact arm 27 lies in an area of the receiving space 21 covered by the inner ring 20.

[0043] The inner ring 20 is seated in the receiving space 21 and carries - fixed to the retaining pin 32 - the supply contact 23. The supply contact 23 is designed as a contact bridge and spans the area between the contact surface 30 of the contact arm 27 and the contact field 14 of the printed circuit board 12.

[0044] The supply contact 23 rests with the mating contact surface 31 of its first contact leg 24 on the contact surface 30 of the contact arm 27 of the connecting contact 17. The second contact leg 25 rests with its free end on the contact field 14 of the printed circuit board 12.

[0045] If a connecting conductor for the electrical supply of the LED 13 is now connected to the connecting contact 17, the electricity is passed on to the circuit board 12 via the coupling of the connecting contact 17 with the supply contact 23.

[0046] Figure 4 shows a printed circuit board 12 whose thickness D1 is indicated by the dashed line vertically relative to the assembly surface A. In the drawing, the printed circuit board 12 with the thickness D1 is less than the base thickness of the outer ring 15 in its height measured vertically relative to the assembly surface A.

[0047] Figure 4 essentially shows the same facts as Figure 5. In this respect, reference is made to the description therein.

[0048] Special attention is paid to Figure 5 on the circuit board 12. This is thicker than the circuit board 12 in Figure 4 and here has a thickness D2. Furthermore, a heat-conducting element 34 is arranged beneath the circuit board, which is located between the underside of the circuit board 12 and the mounting surface A of the counter bearing or heat sink. The heat-conducting element 34 serves to optimize the heat transfer from the circuit board 12 to the heat sink. In addition to the thickness D2, the thickness DW of the heat-conducting element 34 also contributes.

[0049] As a result, the inner ring 20 which overlaps the printed circuit board 12 sits less deeply in the receiving space 21 of the outer ring 15.

[0050] Is in Figure 4the second contact leg 25 is arranged lower with respect to the arrangement surface A than the first contact leg 24 of the supply contact 23, Figure 5 the situation is different. Here, the second contact leg 25 is arranged higher than the first contact leg 24 with respect to the arrangement surface A. This is possible due to the pendulum suspension of the supply contact 23, which is suspended in the inner ring 20 so as to pendulum around the pivot axis S.

[0051] The essential advantage of the invention lies in the separation of the contact arrangement known from the prior art into a connection contact 17 and a supply contact 23, in order to ensure simple assembly of the inner ring 20 in the outer ring 15 and simple arrangement of the printed circuit board 12 in the outer ring 15. Furthermore, the separation of the contact arrangement into connection contact 17 and supply contact 23 enables the tolerance compensation for the printed circuit board thickness, which is also required in the prior art, to be improved. The pendulum arrangement of the supply contact 17 in the inner ring 20 reliably prevents excessive contact pressure, particularly between the supply contact 23 and the contact field 14 of the printed circuit board 12, which is generally finished to a high standard. Damage to the contact field finish due to excessive contact forces is thus reliably avoided, which increases the longevity of a luminaire using the connection element 10 of this invention. List of reference symbols

[0052] 10Connection element 11LED lamp 12Printed circuit board 13LED 14Contact field 15Outer ring 16Frame 17Connection contact 18Contact receptacle 19Cover 20Inner ring 21Receiving space 22Light exit opening 23Supply contact 24First contact leg 25Second contact leg 26Retaining opening 27Contact arm 28Base section 29Insert contour 30Contact surface 31Counter contact surface 32Retaining pins 33Conducting web 34Heat-conducting element AArrangement surface DWThickness D1Thickness D2Thickness LLight emission direction SSwivel axis

Claims

1. A connection element (10) for the electrical connection of an LED lamp (11), - wherein the LED lamp (11) has a circuit board (12) provided with contact pads (14) for the electrical supply of the LED (13), - with a substantially annular frame (16) intended to overlap the circuit board (12) and to mechanically hold it to an arrangement surface (A) of a counter-bearing, - with a contact arrangement that is mounted in the frame (16) and serves to electrically supply the LED (13), - with an outer ring (15) that carries a connection contact (17) for the in particular solderless connection of a connection conductor as the first part of the contact arrangement, - with a supply contact (23) for electrically contacting a contact pad (14) of the circuit board (12) as the second part of the contact arrangement, - wherein the connection contact (17) and the supply contact (23) form a connection with one another, characterized by- an inner ring (20) arranged in the outer ring (15), which together with the outer ring (15) forms the frame (16), - the supply contact (23) carried by the inner ring (20), and further characterized in that - the supply contact (23) has a geometric pivot axis (S) which is arranged parallel to the arrangement surface (A) of the counter bearing and the supply contact (23) is arranged in the inner ring (20) so as to be pivotable about this pivot axis (S).

2. Connection element (10) according to claim 1, characterized in that - the connection contact (17) forms a contact surface (30), - the supply contact (23) forms a counter-contact surface (31), - the contact surface (30) and the counter-contact surface (31) lie directly against one another.

3. Connection element (10) according to claim 2, characterized in thatthe connection contact (17) forms a contact arm (27) which extends into a region of the frame (16) covered by the inner ring (20) and forms the contact surface (30) for the supply contact (23) in this region.

4. Connection element (10) according to one of the preceding claims, characterized in that the supply contact (23) is designed as a contact bridge which spans the area between the contact surface (30) of the connection contact (17) and the contact field (14) of the printed circuit board (12).

5. Connection element (10) according to claim 2 and 4, characterized in that - the supply contact (23) has a first contact leg (24) which forms the mating contact surface (31) for contacting the connection contact (17), - the supply contact (23) has a second contact leg (25) which is provided for resting on the contact field (14) of the printed circuit board (12).

6. Connection element (10) according to claim 5, characterized in that- the first contact leg (24) is deflected in a spring-return elastic manner in the direction of the contact field (14) of the connection contact (17), - the second contact leg (25) is deflected in a spring-return elastic manner in the direction of the contact field (14) of the printed circuit board (12).

7. Connection element (10) according to claim 1, characterized in that the pivot axis (S) is arranged off-center with respect to the distance between the contact surface (30) of the connection contact (17) and the contact field (14) of the printed circuit board (12).

8. Connection element (10) according to one of the preceding claims, characterized in that - the inner ring (20) forms a retaining pin (32) for arranging the supply contact (23), - the supply contact (23) forms a retaining opening (26) for the retaining pin (32), - the retaining pin (32) passes through the retaining opening (26) for anchoring the supply contact (23).

9. Connection element (10) according to claim 8, characterized in thatthe inner ring (20) forms at least one guide web (33) which rests against an edge of the supply contact (23) and prevents rotation of the supply contact (23) about the retaining pin (32).

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