Two-part LED connection element

Abstract

Connection element for the electrical connection of an LED light source, - wherein the LED light source has a circuit board which is provided with contact fields for the electrical supply of the LED, - with a substantially annular frame which is intended to overlap the circuit board and to hold it mechanically 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 serves to supply the LED with electricity, - a connection contact in the outer ring for the in particular solder-free connection of a connection conductor as the first part of the contact arrangement, - a supply contact in the inner ring for making electrical contact with a contact field of the circuit board as the second part of the contact arrangement, - the connection contact and the supply contact form a connection with one another.

Description

[0001] Connection element for the electrical connection of an LED light source, wherein the LED light source has a circuit board which is provided with contact fields for the electrical supply of the LED, with an essentially ring-shaped frame designed to enclose the printed circuit board and mechanically hold it against an arrangement surface of a counter bearing, with a contact arrangement mounted in the frame and serving to supply the LED electrically, with an outer ring carrying a connection contact for connecting a conductor as the first part of the contact arrangement, with a supply contact for electrically connecting 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 interconnected.

[0002] LED connection elements are known, for example, from EP 2 083 489 A1. They serve to mechanically mount an LED light source – a circuit board with an LED mounted on it – to a counter-support, primarily a heat sink. These LED connection elements also provide a contact arrangement that serves both to connect conductors and to contact fields on the circuit board. In this way, the contact arrangement also serves to supply power to the LED light source. Such LED connection elements have the significant advantage of combining both the mechanical mounting 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 in priority document DE 20 2023 105 716 U1. This element is characterized by its two-part construction. An outer ring is designed to be mounted on a heat sink and to precisely accommodate the LED circuit board within a mounting frame. An inner ring is inserted into the outer ring, which surrounds the circuit board and thus secures it within the connection element. Furthermore, the inner ring applies a pressure force to the circuit board, pressing it against the heat sink to optimize heat transfer. This is preferably achieved using spring elements.

[0004] Furthermore, the spring-loaded arrangement of the inner ring within the outer ring allows for the compensation of unavoidable tolerances in the printed circuit board thickness. The inner ring is thus arranged with a certain degree of positional tolerance in the direction of light emission from the LED and in the vertical direction 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 in the direction of the counter bearing and then rotated relative to the outer ring. The inner ring is thus secured in the outer ring in the manner of a bayonet lock.

[0006] The second embodiment is limited to inserting the inner ring vertically into the outer ring, with detent projections of the inner ring being engaged by detent 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 contains, among other things, the LED circuit board. Inside the housing, a flexible circuit board is arranged, which serves as a supply contact and connects to a terminal 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 that ensures the electrical supply to the LED light source even with a two-part connection element.

[0010] The problem of the invention is solved 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 pivotably about this pivot axis in the inner ring.

[0011] The invention utilizes the division of the connection element into an outer ring and an inner ring to separate the contact arrangement, which in the prior art is a single piece, into a connection contact and a supply contact. The connection contact located in the outer ring primarily serves to be connected to the external 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 printed circuit board in the correct position and can be designed in its geometry, in its contact forces and in its contact finishing to create an optimal electrical transition from the supply contact to the contact field of the printed 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 power supply to the LED light source.

[0014] The supply contact has a geometric pivot axis that is arranged parallel to the mounting surface of the counter bearing, wherein the supply contact is pivotably arranged in the inner ring about this pivot axis.

[0015] The key advantage of this feature lies in the fact that the supply contact is movably arranged around the pivot axis and can thus oscillate. It is arranged on the inner ring in a manner similar to a rocker arm or seesaw. The pivot axis is aligned – as described – 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 pivoting suspension of the power supply contact allows for even better compensation of printed circuit board thickness tolerances than if only the spring elasticity of the contact arms were used. Furthermore, the pivoting suspension of the power supply contact also compensates for increased or decreased spring forces on the side of the contact leg resting on the PCB contact area by distributing the force between the two contact legs. In this way, sufficient, but not excessive, contact pressure of the contact legs against their respective contact surfaces is ensured.

[0017] It is also provided that the connecting contact forms a contact surface, the supply contact forms a counter-contact surface, and the contact surface and the counter-contact surface are directly adjacent to each other.

[0018] A particularly preferred embodiment is one in which the connecting contact forms a contact arm that extends into an area of ​​the frame covered by the inner ring and forms the contact surface for the supply contact in this area.

[0019] This design ensures a particularly simple connection between the terminal contact and the supply contact, since the mutual contact surfaces are oriented towards each other and exposed when the inner ring is inserted into the outer ring, opposite to the direction of light emission. Inserting the inner ring into the outer ring effectively covers the contact surface of the terminal contact intended for the supply contact, thus ensuring the necessary protection against accidental contact.

[0020] Specifically, the supply contact is designed as a contact bridge spanning 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 counter-contact surface for contacting the connection contact and the supply contact has a second contact leg which is intended for resting 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 connecting contact and the second contact leg is deflected in a spring-return elastic manner in the direction of the contact field of the circuit board.

[0023] The spring-return elasticity of the supply contact's contact pins ensures that sufficiently high contact forces exist between both the connection contact and the supply contact, as well as between the supply contact and the contact area of ​​the printed circuit board, to establish a reliable electrical connection. Furthermore, this spring-return elasticity can also help to compensate for PCB thickness tolerances without compromising contact quality.

[0024] Furthermore, it is possible that the pivot axis is arranged off-center with respect to the distance between the contact surface of the terminal contact and the contact field of the circuit board.

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

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

[0027] Such a retaining pin can be manufactured particularly easily using injection molding. The power supply contact can also be mounted very easily on such a retaining pin. The retaining pin is oriented vertically to the mounting surface of the counter bearing and parallel to the light emission direction of the LED. However, by appropriately designing the connection with the power supply contact, this pin allows for a geometric pivot axis that is parallel to the mounting surface of the counter bearing.

[0028] To ensure a defined movement of the supply contact around its pivot axis, the inner ring is designed to form at least one guide rib which rests against an edge of the supply contact and prevents the supply contact from rotating around the retaining pin.

[0029] The following description of an embodiment of the invention highlights further features and advantages. It shows: Figure 1 an exploded view of the connection element according to the invention, Figure 2 a view from below of the inner ring of the connecting element Figure 1 , Figure 3 a view of the connecting element after 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 by the reference numeral 10.

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

[0032] The connecting element 10 initially comprises an outer ring 15, the underside of which, facing away from the light emission direction L of the LED 13, also rests on the mounting 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 mounting surface A.

[0033] The outer ring 15 then carries connection contacts 17, which are arranged in contact recesses 18 of the outer ring 15. Each contact recess 18 is closed by a cover 19 on the top side of the outer ring 15, so that the connection contacts 17, insofar as they are seated in the contact recess 18, are protected from contact.

[0034] The connecting element 10 then comprises an inner ring 20, which is inserted into a receiving space 21 formed by the outer ring 15. In its assembled state, the inner ring 20 covers the circuit board 12, but allows light emission from the light source 11 through its central light emission 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 retaining opening 26.

[0036] Each terminal contact 17 has a contact arm 27. When the terminal contact 17 is seated in its associated contact receptacle 18, the contact arm 27 extends from the receptacle 18 and engages in the receiving space 21, which is formed by the outer ring 15 to receive 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 serves to receive the contact arm 27 extending from the receiving space 21. The insert contour 29 is advantageous in every respect, but not essential for the invention.

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

[0038] Figure 2Figure 1 shows a view of the underside of the inner ring 20. On both sides of the light emission aperture 22, retaining pins 32 are formed by the inner ring 20. Each retaining pin 32 is oriented approximately parallel to the light emission direction L or perpendicular to the mounting 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-like head at its free end after the supply contact 23 is inserted. Two guide ribs 33 are formed by the inner ring 20 on either side of each supply contact. Two guide ribs 33 accommodate a supply contact 23 between them. In this way, the guide ribs 33 prevent the supply contact from rotating around the longitudinal axis of the retaining pin 32.

[0039] The supply contact 23 is held on each retaining pin 32 with a certain degree of play, so that each supply contact 23 – guided by the guide webs 33 – can pivot about a pivot axis S. As shown in Figure 2 As becomes clear, the pivot axis S lies parallel to the arrangement surface A for the circuit board 12, so that the supply contact 23 can swing in the manner of a rocker or a balance beam.

[0040] Figure 3 shows a top view of the composite connection element 10. Figure 1including LED light source 11. The figure shows how the inner ring 20 sits inside the outer ring 15 and how the light emission opening 22 of the inner ring 20 surrounds the LED 13, allowing the light emitted by the LED 13 to escape unhindered. The figure also shows how the covers 19 close the contact point 18 on the top side of the connection element 10, to clarify the section view AA. This section line extends lengthwise through the supply contact 23.

[0041] Figure 4 shows a section view according to 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 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 connecting contact 17 sits in its contact receptacle 18, which is closed at the top by a cover 19. The contact arm 27 extends from the contact receptacle 18 into the receiving space 21 for the inner ring 20. It rests 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 that is covered by the inner ring 20.

[0043] The inner ring 20 sits 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 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 terminal contact 17. The second contact leg 25 rests with its free end on the contact field 14 of the circuit board 12.

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

[0046] Figure 4 Figure 1 shows a printed circuit board 12, whose thickness D1, measured vertically to the mounting surface A (indicated by the dashed line), is less than the base thickness of the outer ring 15.

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

[0048] Particular attention is paid to Figure 5 to place it on circuit board 12. This is thicker than circuit board 12 in Figure 4 and has a thickness D2. Furthermore, a thermal interface element 34 is arranged below the circuit board, located between the underside of the circuit board 12 and the mounting surface A of the counter bearing or heat sink. The thermal interface element 34 serves to optimize the heat transfer from the circuit board 12 to the heat sink. Therefore, in addition to the thickness D2, the thickness DW of the thermal interface element 34 also contributes to the overall thickness.

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

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

[0051] The main advantage of the invention lies, firstly, in separating 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 circuit board 12 in the outer ring 15. Furthermore, separating the contact arrangement into connection contact 17 and supply contact 23 allows for improved tolerance compensation for the circuit board thickness, which is also necessary in the prior art. The pivoting arrangement of the supply contact 17 in the inner ring 20 reliably prevents excessive contact pressure, particularly between the supply contact 23 and the typically high-quality contact area 14 of the circuit board 12. Damage to the contact area finish caused by excessive contact forces is thus reliably avoided, which increases the service life of a luminaire using the connection element 10 of this invention. Reference symbol list

[0052] 10 Connection element 11 LED light source 12 Circuit board 13 LED 14 Contact field 15 Outer ring 16 Frame 17 Connection contact 18 Contact receptacle 19 Cover 20 Inner ring 21 Receptacle 22 Light emission opening 23 Power supply contact 24 First contact leg 25 Second contact leg 26 Retaining opening 27 Contact arm 28 Base section 29 Insert contour 30 Contact surface 31 Counter-contact surface 32 Retaining pins 33 Conductor rib 34 Heat-conducting element AArrangement area DWThickness D1Thickness D2Thickness LLight emission direction SSwivel axis

Claims

1. Connection element (10) for the electrical connection of an LED light source (11), - wherein the LED light source (11) comprises a printed circuit board (12) provided with contact pads (14) for the electrical supply of the LED (13), - comprising a substantially annular frame (16) designed to cover the printed circuit board (12) and mechanically connect it to a an arrangement surface (A) of a counter-bearing, - with a contact assembly mounted in the frame (16) and serving to supply power to the LED (13), - with an outer ring (15) which has a connection contact (17) for the, in particular, solder-free connection of a connecting conductor as the first part of contact arrangement, - with a supply contact (23) for making electrical contact with a contact pad (14) on the printed circuit board (12) as a second part of the contact arrangement, - whereby the connection contact (17) and the supply contact (23) are connected to one another, characterised 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 characterised in that - the supply contact (23) has a geometric pivot axis (S) which is arranged parallel to the mounting 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, characterised in that - the connection contact (17) forms a contact surface (30), - the supply contact (23) forms a mating contact surface (31) - the contact surface (30) and the mating contact surface (31) are directly, adjacent to each other.

3. Connection element (10) according to claim 2, characterised in that in that the 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, characterised in that the supply contact (23) is formed as a contact bridge which spans the area between the contact surface (30) of the connection contact (17) and the contact pad (14) of the printed circuit board (12).

5. Connection element (10) according to claims 2 and 4, characterised in that - the power supply contact (23) has a first contact leg (24) which forms the mating contact surface (31) for making contact with the terminal contact (17), - the supply contact (23) comprises a second contact leg (25) which is designed to rest on the contact pad (14) of the printed circuit board (12).

6. Connection element (10) according to claim 5, characterised in that - the first contact leg (24) is deflected in the direction of the contact pad (14) of the terminal contact (17) by a spring-return force, - the second contact leg (25) is deflected by a spring return force in the direction of the contact pad (14) of the printed circuit board (12).

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

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

9. Connection element (10) according to claim 8, characterised in that the inner ring (20) forms at least one guide rib (33) which abuts against an edge of the supply contact (23) and prevents the supply contact (23) from rotating about the retaining pin (32).

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