LED SYSTEM WITHOUT HEAT SINK

Abstract

The invention relates to a powerful, robust and durable light-emitting diode lighting system with a protection rating of up to IP69, while maintaining a low manufacturing cost.

It consists of an insulated metal substrate, on which at least one light-emitting diode is placed, supplied by a cable or a connector. The resulting circuit is then wrapped in a heat-shrinkable sheath, which will remove the air and dissipate the heat from the substrate and diodes in an optimal manner, the heat dissipation power thereof being about ten times that of air. Each end is then overmoulded, in order to make the system sealed and robust. The overmoulding can be used to add a sealing lip around the connector, as well as specific recesses to allow various attachment methods, individually or in groups.

The device according to the invention is intended for domestic, industrial and horticultural lighting, depending on whether a translucent or transparent substrate is used.

Claims

1. The device consists of an insulated metal substrate (1) in the form of a straight block, the length of which is at least twice as great as the width, which is at least twice as great as the thickness, comprising, on one of the two larger surfaces, at least one SMD-type (Surface Mounted Device) or COB-type (Chip on Board) light-emitting diode (2), supplied by a connector (3) at one of the ends of the circuit, characterised in that said substrate (1) is covered with a transparent or translucent heat-shrinkable sheath (4) covering the diodes, and in that the substrate (1) and the sheath (4) are overmoulded at the ends by a polymer (5) electrically insulating the system.

2. Device according to claim 1, characterised in that the material used for the overmoulding (5) is an elastomer, and in that this overmoulding (5) has, at the opening of the connector, a lip (6), which seals the connection (3).

3. Device according to claim 2, characterised in that the substrate (1) has a recess (7) at each end, passing through the thickness, and located outside the area covered by the sheath (4), recesses that the overmoulding (5) covers without sealing.

4. Device according to claim 3, characterised in that a second block (8) consisting of a metal alloy with a higher modulus of elasticity than the insulated metal substrate (1) having two recesses which correspond to the recesses (7) of the circuit (1) is stuck to the substrate (1) on the surface opposite the diodes, by means of a thermally conductive material.

5. Device according to claim 3, characterised in that each end of the system has a recess (9) in the overmoulding which is not both circular and concentric to the recess (7).

6. The device consists of an insulated metal substrate (1) in the form of a straight block, the length of which is at least twice as great as the width, which is at least twice as great as the thickness, comprising, on one of the two larger surfaces, at least one SMD-type (Surface Mounted Device) or COB-type (Chip on Board) light-emitting diode (2), supplied by a cable at one of the ends of the circuit, characterised in that said substrate (1) is covered with a transparent or translucent heat-shrinkable sheath (4) covering the diodes, and in that the substrate (1) and the sheath (4) are overmoulded at the ends by a polymer (5) electrically insulating the system.

7. Device according to claim 4, characterised in that each end of the system has a recess (9) in the overmoulding which is not both circular and concentric to the recess (7).

Description

[0012] The appended drawings illustrate the invention:

[0013] FIG. 1 is a perspective view of the insulated metal substrate with an LED array as well as a connector installed on one of the two larger surfaces.

[0014] FIG. 2 is a perspective view of the circuit coated with the heat-shrunk sheath and overmoulded at the ends by the polymer.

[0015] FIG. 3 is a longitudinal section view of the lighting system with the sealing lip around the connector.

[0016] FIG. 4 is a perspective view of the lighting system with an attachment recess at each end.

[0017] FIG. 5 is a longitudinal section view of the lighting system with a second metal alloy block stuck to the substrate.

[0018] FIG. 6 is a perspective view of the lighting system with a non-circular recess at each end.

[0019] FIG. 7 is a perspective view of two lighting systems attached together by means of two brackets.

[0020] With reference to the drawings, FIG. 1 shows a device comprising an insulated metal substrate (1), on which a connector (3) and an array of surface-mounted light-emitting diodes (2) are placed. In FIG. 2, the substrate (1) and the array of diodes (2) are inserted into a heat-shrinkable sheath (4), so as to remove the air trapped between the diodes and the sheath. An elastomeric overmoulding (5) covers each of the two ends of the substrate (1) and the sheath (4), as well as the connector (3) at one of the ends, so as to ensure the protection and sealing of the array.

[0021] In the embodiment according to FIG. 3, the overmoulding (5) around the connector (3) forms a circular lip (6), which will fit and compress around the complementary power connector, in order to increase the protection rating of the exposed connector.

[0022] In the embodiment according to FIG. 4, the overmoulding (5) has a recess (7), which is smaller than the recess of the substrate, in order to cover it without sealing it and thus to allow the device to be attached by means of clips or screws.

[0023] In the embodiment according to FIG. 5, a metal block (8) is stuck to the back of the substrate (1) by means of a double-sided thermally conductive adhesive tape, before wrapping the device in the heat-shrinkable sheath and overmoulding it at its ends, in order to increase the mechanical rigidity of the array.

[0024] In the embodiment according to FIG. 6, recesses (9) are made during overmoulding, around the attachment recesses (7), to prevent rotation between the lighting system and the holding parts to be clipped on. An example of the assembly of two lighting systems is shown in FIG. 7.

[0025] By way of non-limiting example, the substrate, made of aluminium, will have dimensions of around 500 millimetres long, 30 millimetres wide and 1 millimetre thick. The metal block to increase rigidity will have the same dimensions and will be made of stainless steel. The diodes will be of the SMD2835 type, and will consume 20 watts in total. The connector will be of DC 5.5×2.1 millimetres type. The overmoulding will consist of a thermoplastic elastomer in order to facilitate moulding. The material used for the heat-shrinkable sheath will be a fluoropolymer with a shrinkage temperature greater than 140° C., in order to remain stable under the temperature of the diodes which can reach 80° C. It can be translucent or transparent depending on the intended application.

[0026] The device according to the invention is particularly intended for domestic, industrial and horticultural lighting.