Lighting device with improved cooling

Abstract

The present disclosure relates to a lighting device (100) comprising at least one printed circuit board (120), PCB, at least one holding at least one light-emitting diode (130), LED. The lighting device (100) further comprises at least one second heat generating unit (140). The lighting device (100) also comprises a fluid conduction system (150) arranged to conduct liquid (155). The fluid conduction system (150) is arranged for cooling both the at least one printed circuit board (120) holding the at least one LED (130) and the at least one second heat generating unit (140). The lighting device (100) additionally comprises a pump (160) arranged to circulate said liquid (155) through said fluid conduction system (150).

Description

[0001] LIGHTING DEVICE WITH IMPROVED COOLING

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to lighting devices with efficient cooling of both printed circuit board mounted LEDs as well as other heat generating power components.

[0004] BACKGROUND ART

[0005] Light emitting diode lighting devices generate heat during operation that may potentially shorten lifetime, negatively affect the power spectrum of the LEDs and otherwise negatively effect the performance of the lighting device. There is thus a need in the art for improved cooling of lighting devices.

[0006] SUMMARY OF THE INVENTION

[0007] One objective of the present disclosure is to provide lighting devices with improved cooling systems.

[0008] This objective has been achieved by means of a lighting device as defined in claim 1 .

[0009] Thus, according to a first aspect there is provided a lighting device comprising at least one printed circuit board, PCB, at least one holding at least one light-emitting diode, LED. The lighting device further comprises at least one second heat generating unit. The lighting device also comprises a fluid conduction system arranged to conduct liquid. The fluid conduction system is arranged for cooling both the at least one printed circuit board holding the at least one LED and the at least one second heat generating unit. The lighting device additionally comprises a pump arranged to circulate said liquid through said fluid conduction system. The lighting device not only cools the LED via the PCB on which the LED is mounted, but also additional heat generating components represented by the at least one second heat generating unit, such as components configured to power and / or control the LED. Thus, a lighting device comprising a cooling mechanism in the form of a fluid conduction system configured to remove heat due to non-ideal efficiency of power components of the lighting device.

[0010] According to some aspects, a rear surface of the printed circuit board and / or a rear surface of the at least one second heat generating unit forms part of the wall of the fluid conduction system so that the liquid is in direct contact with the rear surface of the printed circuit board and / or the at least one second heat generating unit. The liquid being in direct contact with the with the rear surface of the printed circuit board and / or the at least one second heat generating unit improves heat transport away from the with the rear surface of the printed circuit board and / or the at least one second heat generating unit.

[0011] According to some aspects, the fluid conduction system further comprises a liquid cooling plate, and wherein a rear surface of the printed circuit board and / or wherein the at least one second heat generating unit is in contact with the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the rear surface and / or the at least one second heat generating unit to the liquid used within the fluid conduction system. Liquid cooling plates offer cooling that is much more efficient than conventional air cooling due to the specific heat and heat transfer coefficient are much higher than those of air. The use of liquid cooling plates offers convenient design alternatives of the lighting device, since a liquid cooling plate can be moved easily, requiring only minimal rewiring of fluid conduction cables (and possible electrical cables).

[0012] According to some aspects, a rear surface of the at least one second heat generating unit forms part of the wall of the pump so that the liquid is in direct contact with the rear surface of the at least one second heat generating unit. Integrating the second heat generating unit with the pump wall reduces the volume take by the lighting device. A further technical effect and advantage is that the second heat generating unit is cooled with the high efficiency provided by direct contact with the liquid, while requiring no to minimal additional electrical wiring or liquid conducting pipes to accommodate the location of the second heat generating unit.

[0013] According to some aspects, at least one of the at least one second heat generating unit comprises a heat generating component. The heat generating component is in contact with a liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component to the liquid used within the fluid conduction system. According to some aspects, at least one of the at least one second heat generating unit comprises a heat generating component. The heat generating component is thermally connected to a liquid cooling plate via a metal sheet arranged between the heat generating component and the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component via the metal sheet to the liquid used within the fluid conduction system. Having the heat generating components of the second heat generating units in direct contact with the cooling surface, either the liquid cooling plate itself or via a metal sheet, offer more efficient cooling than passive cooling. According to some aspects, the fluid conduction system further comprises a heat exchanger arranged to cool the liquid. A heat exchanger enables active cooling of the liquid, and thus offer a more efficient cooling of the lighting device over passive cooling alone.

[0014] According to some aspects, a rear surface of the at least one second heat generating unit forms part of the wall of the heat exchanger so that the liquid is in direct contact with the rear surface of the at least one second heat generating unit. This enables the cooling of the liquid and the second heat generating unit to act synergistically to provide more efficient cooling of the second heat generating unit than had the second heat generating unit been cooled by either passive cooling, the liquid or the heat exchanger alone.

[0015] According to some aspects, the at least one second heat generating unit comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter. The LED driving electronics is configured to power and / or control the at least one LED of the at least one printed circuit board. According to some aspects, the at least one second heat generating unit comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger. By configuring the cooling system to also cool other heat generating components configured to power and / or control electrical components of the lighting device, a safer and more efficient lighting device is provided.

[0016] According to some aspects, the at least one printed circuit board and / or a printed circuit board of the at least one second heat generating unit comprises a metal core printed circuit board, MC-PCB. The metal core enables efficient transport of heat from a front surface having mounted LEDs to a rear surface opposite said front surface. The MC-PCB thereby enables a synergistic effect together with the cooling system when the cooling system is directly or indirectly thermally connected to the rear surface, e.g. via a liquid cooling plate or arranged such that the liquid is in direct contact with the rear surface.

[0017] The present disclosure will become apparent from the detailed description given below. The detailed description and specific aspects disclose preferred aspects of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure. Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of examples, when taken in conjunction with the accompanying drawings.

[0020] Figure 1 illustrates a lighting device according to the present disclosure;

[0021] Figure 2 illustrates a lighting device according to the present disclosure;

[0022] Figure 3 illustrates a lighting device according to the present disclosure;

[0023] Figure 4 illustrates a lighting device according to the present disclosure;

[0024] Figure 5 illustrates a lighting device according to the present disclosure; and

[0025] Figure 6 illustrates a lighting device according to the present disclosure.

[0026] DETAILED DESCRIPTION

[0027] Figure 1 illustrates a lighting device 100 according to the present disclosure. The lighting device 100 comprises at least one printed circuit board 120, PCB, at least one PCB holding at least one light-emitting diode 130, LED. In order to facilitate effective cooling, the PCB 120 is preferably configured to effectively enable thermal transport from the LED to the cooling system. One way of doing so is to effectively enable thermal transport from a front surface of the PCB 120 on which the LED 130 is mounted to a rear surface of the PCB opposite said front surface, and then thermally connect a cooling mechanism to said rear surface, as discussed above and below. According to some aspects, the at least one printed circuit board 120 and / or a printed circuit board of the at least one second heat generating unit 140 comprises a metal core printed circuit board, MC-PCB. According to some aspects, the at least one printed circuit board 120 and / or the printed circuit board of the at least one second heat generating unit 140 comprises a ceramic PCB. Metal has high thermal conductivity, and thus facilitate heat generated by the at least one LED to reach the rear surface of the PCB 120. Likewise, the ceramic of the ceramic PCB can be a ceramic with high thermal conductivity and minimal expansion coefficient, thus serving the same function as the MC-PCB. According to some aspects, the at least one printed circuit board 120 and / or the printed circuit board of the at least one second heat generating unit 140 comprises a set of thermally conductive through-vias, wherein each through-via is configured to conduct heat from the at least one LED 130 to a rear surface of the PCB 120 opposite the front surface on which the at least one LED 130 is mounted.

[0028] The lighting device 100 further comprises at least one second heat generating unit 140. According to some aspects, the at least one second heat generating unit 140 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0029] The lighting device also comprises a fluid conduction system 150 arranged to conduct liquid 155, wherein the fluid conduction system 150 is arranged for cooling both the at least one printed circuit board 120 holding the at least one LED 130 and the at least one second heat generating unit 140. The lighting device 100 additionally comprises a pump 160 arranged to circulate said liquid 155 through said fluid conduction system 150.

[0030] All electrical power components generate heat during operational use due to natural power conversion inefficiency as well as natural defects of components. In addition to the at least one LED 130, which will generate light and heat, other electrically powered components may be represented by the at least one second heat generating unit 140. In particular, as described further above and below, the at least one second heat generating unit 140 may comprise LED driving circuitry which itself generates heat when powering the at least one LED 130.

[0031] Thus, with the fluid conduction system 150 configured to cool the at least one second heat generating unit 140, a lighting device 100 is provided that cools heat emitting components other than just the LED light source. This results in a lighting system that has longer life expectancy, operates at an overall increased power efficiency and can be potentially safer to operate as there are now fewer hot components during operation.

[0032] According to some aspects, the fluid conduction system 150 further comprises a heat exchanger 170 arranged to cool the liquid 155. According to some aspects, the at least one second heat generating unit 140 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 140 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger. The heat exchanger 170 improves the transport of heat away from the fluid conduction system 150 and thus improves the cooling of the lighting device 100. The at least one second heat generating unit 140 comprising power electronics and / or a motor and / or a transformer for fans of the heat exchanger 170 acts synergistically with the cooling system, since cooling the power electronics and / or a motor and / or a transformer for fans of the heat exchanger improves efficiency of the fluid cooling system and improves the lifetime of the cooled components, which confer the same technical effects and advantages to the lighting device 100.

[0033] As described above, heat may be transported away from the at least one LED 130 via a rear surface of the PCB 120 it is mounted on, when the rear surface is thermally connected to the fluid conduction system 150. Likewise, heat may be transported of a thermally conductive surface, herein referred to as a rear surface, of the at least one second heat generating unit 140 in a similar manner.

[0034] One way to achieve the thermal connection between the rear surface of the PCB 120 or the second heat generating unit 140 is to configure the fluid conduction system such that the rear surface is directly exposed to the liquid being circulated through the fluid conduction system 150.

[0035] Thus, according to some aspects, a rear surface of the printed circuit board 120 and / or a rear surface of the at least one second heat generating unit 140 forms part of the wall of the fluid conduction system 150 so that the liquid 155 is in direct contact with the rear surface of the printed circuit board 120 and / or the at least one second heat generating unit 140.

[0036] According to some aspects, the printed circuit board 120 is attached to a designated opening of the wall of the fluid conduction system, by means of a mount plate, with a fluid tight seal between the PCB and the mount plate. Similarly, according to some aspects, at least one second heat generating unit 140 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the at least one second heat generating unit and the mount plate.

[0037] The second heat generating unit may be integrated into components of the lighting device, such as the pump and the heat exchanger, while simultaneously being cooled by the fluid conduction system 150.

[0038] This may reduce the overall profile of the lighting device 100, i.e. the size of the lighting device, while simultaneously provide cooling for the second heat generating unit 140, which could be a power device of the pump or the heat exchanger, or LED driving electronics configured to power and / or control the at least one LED, as discussed further above and below. Thus, according to some aspects, a rear surface of the at least one second heat generating unit 140 forms part of the wall of the pump 160 so that the liquid 155 is in direct contact with the rear surface of the at least one second heat generating unit 140. According to some aspects, a rear surface of the at least one second heat generating unit 140 forms part of a wall of the heat exchanger so that the liquid 155 is in direct contact with the rear surface of the at least one second heat generating unit 140. According to some aspects, at least one second heat generating unit 140 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the at least one second heat generating unit and the mount plate.

[0039] The second heat generating unit 140 often comprises a PCB with heat generating components mounted on the PCB of the second heat generating unit. If the heat generating components can be brought into direct contact with the liquid 155 of the fluid conduction system 150 without short circuiting, e.g. by being covered with a liquid resistant material, such as resin, more efficient cooling may be provided. Thus, according to some aspects at least one of the at least one second heat generating unit 140 comprises a heat generating component, and wherein the heat generating component is arranged so that the liquid 155 is in direct contact with the heat generating component. According to some aspects, at least one second heat generating unit 140 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the at least one second heat generating unit and the mount plate, such that the heat generating component is in direct contact with the liquid 155.

[0040] Additional cooling can be obtained by arranging channels in the at least one printed circuit board 120 and / or a printed circuit board of the at least one second heat generating unit 140, wherein the channels are configured to conduct the liquid 155 of the fluid conduction system 150 through the respective PCB and transport heat from the respective PCB to the liquid 155.

[0041] Another way to achieve the thermal connection between the rear surface of the PCB 120 or the second heat generating unit 140 is to provide the fluid conduction system with a component suitable for transferring heat between the rear surface and the liquid. An example of such a component is a liquid cooling plate, also known as a cold plate, which is a device comprising fluid conducting channels arranged to conduct a liquid to exchange heat with a (hot) surface of the liquid cooling plate, thereby transporting heat from the hot surface to the cooler liquid.

[0042] Thus, according to some aspects, the fluid conduction system 150 further comprises a liquid cooling plate, and wherein a rear surface of the printed circuit board 120 and / or the at least one second heat generating unit 140 is in contact with the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the rear surface and / or the at least one second heat generating unit 140 to the liquid 155 used within the fluid conduction system 150.

[0043] The second heat generating unit 140 often comprises a PCB with heat generating components mounted on the PCB. In such cases, the rear surface of the second heat generating unit often refers to a rear surface of the PCB. It may however be more effective to bring the heat generating components in direct contact with a cooling surface, either in direct contact with the liquid cooling plate or with a metal sheet arranged between the liquid cooling plate and the heat generating component. Thus, according to some aspects, at least one of the at least one second heat generating unit 140 comprises a heat generating component, and wherein the heat generating component is in contact with a liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component to the liquid 155 used within the fluid conduction system 150. According to some aspects, at least one of the at least one second heat generating unit 140 comprises a heat generating component, and wherein the heat generating component is thermally connected to a liquid cooling plate via a metal sheet arranged between the heat generating component and the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component via the metal sheet to the liquid 155 used within the fluid conduction system 150.

[0044] When two components are thermally connected, e.g. a liquid cooling plate being thermally connected to a rear surface of the printed circuit board 120 and / or the at least one second heat generating unit 140, possibly with a metal sheet arranged in-between, the thermal connection may be further facilitated by thermal paste arranged to connect the surfaces where heat is to be transported from one component to the other, such as the rear surface of the printed circuit board 120 and / or the at least one second heat generating unit 140 with the liquid cooling plate.

[0045] Figures 2-6 illustrate aspects of the disclosed lighting device of figure 1 in further detail. It is to be understood that technical features and aspects disclosed in relation to any of the figures may be transferred freely.

[0046] Figure 2 illustrates a lighting device 200 according to the present disclosure. Specifically, figure 2 illustrates aspects where hot surfaces are cooled by being in direct contact with the liquid of the cooling system. The lighting device 200 comprises at least one printed circuit board 220, PCB, at least one PCB holding at least one light-emitting diode 230, LED. According to some aspects, the at least one printed circuit board 220 and / or a printed circuit board of the at least one second heat generating unit 240 comprises a metal core printed circuit board, MC-PCB.

[0047] The lighting device 200 further comprises at least one second heat generating unit 240. According to some aspects, the at least one second heat generating unit 240 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0048] The lighting device also comprises a fluid conduction system 250 arranged to conduct liquid 255, wherein the fluid conduction system 250 is arranged for cooling both the at least one printed circuit board 220 holding the at least one LED 230 and the at least one second heat generating unit 240. The lighting device 200 additionally comprises a pump 260 arranged to circulate said liquid 255 through said fluid conduction system 250. According to some aspects, the fluid conduction system 250 further comprises a heat exchanger 270 arranged to cool the liquid 255.

[0049] According to some aspects, the at least one second heat generating unit 240 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 240 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger.

[0050] According to some aspects, a rear surface of the printed circuit board 220 and / or a rear surface of the at least one second heat generating unit 240 forms part of the wall of the fluid conduction system 250 so that the liquid 255 is in direct contact with the rear surface of the printed circuit board 220 and / or the at least one second heat generating unit 240.

[0051] According to some aspects, the PCB 220 and / or at least one second heat generating unit 240 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the PCB and / or at least one second heat generating unit and the mount plate.

[0052] According to some aspects, a rear surface of the at least one second heat generating unit 240 forms part of the wall of the pump 260 so that the liquid 255 is in direct contact with the rear surface of the at least one second heat generating unit 240.

[0053] According to some aspects, a rear surface of the at least one second heat generating unit 240 forms part of the wall of the heat exchanger so that the liquid 255 is in direct contact with the rear surface of the at least one second heat generating unit 240.

[0054] Figure 3 illustrates a lighting device 300 according to the present disclosure. In particular, figure 3 illustrates indirect cooling by means of liquid cooling plates. The lighting device 300 comprises at least one printed circuit board 320, PCB, at least one PCB holding at least one light-emitting diode 330, LED. According to some aspects, the at least one printed circuit board 320 and / or a printed circuit board of the at least one second heat generating unit 340 comprises a metal core printed circuit board, MC-PCB.

[0055] The lighting device 300 further comprises at least one second heat generating unit 340. According to some aspects, the at least one second heat generating unit 340 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0056] The lighting device also comprises a fluid conduction system 350 arranged to conduct liquid 355, wherein the fluid conduction system 350 is arranged for cooling both the at least one printed circuit board 320 holding the at least one LED 330 and the at least one second heat generating unit 340. The lighting device 300 additionally comprises a pump 360 arranged to circulate said liquid 355 through said fluid conduction system 350.

[0057] According to some aspects, the fluid conduction system 350 further comprises a heat exchanger 370 arranged to cool the liquid 355.

[0058] According to some aspects, the at least one second heat generating unit 340 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 340 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger.

[0059] According to some aspects, the fluid conduction system 350 further comprises a liquid cooling plate, and wherein a rear surface of the printed circuit board 320 and / or the at least one second heat generating unit 340 is in contact with the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the rear surface and / or the at least one second heat generating unit 340 to the liquid 355 used within the fluid conduction system 350.

[0060] According to some aspects, at least one of the at least one second heat generating unit 340 comprises a heat generating component, and wherein the heat generating component is in contact with a liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component to the liquid 355 used within the fluid conduction system 350.

[0061] According to some aspects, at least one of the at least one second heat generating unit 340 comprises a heat generating component, and wherein the heat generating component is thermally connected to a liquid cooling plate via a metal sheet arranged between the heat generating component and the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component via the metal sheet to the liquid 355 used within the fluid conduction system 350.

[0062] Figure 4 illustrates a lighting device 400 according to the present disclosure. In particular, figure 4 illustrates indirect cooling be means of liquid cooling plates, further illustrating that the liquid cooling plates may be integrated with components of the lighting device, in particular the pump and / or heat exchanger, if present. The lighting device 400 comprises at least one printed circuit board 420, PCB, at least one PCB holding at least one light-emitting diode 430, LED. According to some aspects, the at least one printed circuit board 420 and / or a printed circuit board of the at least one second heat generating unit 440 comprises a metal core printed circuit board, MC- PCB.

[0063] The lighting device 400 further comprises at least one second heat generating unit 440.

[0064] According to some aspects, the at least one second heat generating unit 440 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0065] The lighting device also comprises a fluid conduction system 450 arranged to conduct liquid 455, wherein the fluid conduction system 450 is arranged for cooling both the at least one printed circuit board 420 holding the at least one LED 430 and the at least one second heat generating unit 440. The lighting device 400 additionally comprises a pump 460 arranged to circulate said liquid 455 through said fluid conduction system 450.

[0066] According to some aspects, the fluid conduction system 450 further comprises a heat exchanger 470 arranged to cool the liquid 455.

[0067] According to some aspects, the at least one second heat generating unit 440 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 440 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger.

[0068] According to some aspects, the fluid conduction system 450 further comprises a liquid cooling plate, and wherein a rear surface of the printed circuit board 420 and / or the at least one second heat generating unit 440 is in contact with the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the rear surface and / or the at least one second heat generating unit 440 to the liquid 455 used within the fluid conduction system 450.

[0069] According to some aspects, at least one of the at least one second heat generating unit 440 comprises a heat generating component, and wherein the heat generating component is in contact with a liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component to the liquid 455 used within the fluid conduction system 450.

[0070] According to some aspects, at least one of the at least one second heat generating unit 440 comprises a heat generating component, and wherein the heat generating component is thermally connected to a liquid cooling plate via a metal sheet arranged between the heat generating component and the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component via the metal sheet to the liquid 455 used within the fluid conduction system 450.

[0071] Figure 5 illustrates a lighting device 500 according to the present disclosure. In particular, figure 5 illustrates direct cooling, wherein the liquid of the fluid conduction system is in direct contact with surfaces arranged to be cooled; figure 5 further illustrates that the direct cooling mechanism may be integrated with the pump and / or the heat exchanger, if present. The lighting device 500 comprises at least one printed circuit board 520, PCB, at least one PCB holding at least one light-emitting diode 530, LED. According to some aspects, the at least one printed circuit board 520 and / or a printed circuit board of the at least one second heat generating unit 540 comprises a metal core printed circuit board, MC-PCB.

[0072] The lighting device 500 further comprises at least one second heat generating unit 540. According to some aspects, the at least one second heat generating unit 540 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0073] The lighting device also comprises a fluid conduction system 550 arranged to conduct liquid 555, wherein the fluid conduction system 550 is arranged for cooling both the at least one printed circuit board 520 holding the at least one LED 530 and the at least one second heat generating unit 540. The lighting device 500 additionally comprises a pump 560 arranged to circulate said liquid 555 through said fluid conduction system 150.

[0074] According to some aspects, the fluid conduction system 550 further comprises a heat exchanger 570 arranged to cool the liquid 555.

[0075] According to some aspects, the at least one second heat generating unit 540 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 540 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger.

[0076] According to some aspects, a rear surface of the printed circuit board 520 and / or a rear surface of the at least one second heat generating unit 540 forms part of the wall of the fluid conduction system 550 so that the liquid 555 is in direct contact with the rear surface of the printed circuit board 520 and / or the at least one second heat generating unit 540. According to some aspects, the PCB 520 and / or at least one second heat generating unit 540 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the PCB and / or at least one second heat generating unit and the mount plate.

[0077] According to some aspects, a rear surface of the at least one second heat generating unit 540 forms part of the wall of the pump 560 so that the liquid 555 is in direct contact with the rear surface of the at least one second heat generating unit 540.

[0078] According to some aspects, a rear surface of the at least one second heat generating unit 540 forms part of the wall of the heat exchanger so that the liquid 555 is in direct contact with the rear surface of the at least one second heat generating unit 540. Figure 6 illustrates a lighting device 600 according to the present disclosure. In particular, figure 6 illustrates details of possible combinations of direct and indirect cooling, possibly integrated with the pump and / or heat exchanger, if present. The lighting device 600 comprises at least one printed circuit board 620, PCB, at least one PCB holding at least one light-emitting diode 630, LED. According to some aspects, the at least one printed circuit board 620 and / or a printed circuit board of the at least one second heat generating unit 640 comprises a metal core printed circuit board, MC-PCB.

[0079] The lighting device 600 further comprises at least one second heat generating unit 640. According to some aspects, the at least one second heat generating unit 640 comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

[0080] The lighting device also comprises a fluid conduction system 650 arranged to conduct liquid 655, wherein the fluid conduction system 650 is arranged for cooling both the at least one printed circuit board 620 holding the at least one LED 630 and the at least one second heat generating unit 640. The lighting device 600 additionally comprises a pump 660 arranged to circulate said liquid 655 through said fluid conduction system 650.

[0081] According to some aspects, the fluid conduction system 650 further comprises a heat exchanger 670 arranged to cool the liquid 655.

[0082] According to some aspects, the at least one second heat generating unit 640 comprises power electronics and / or a motor and / or a transformer for fans. According to some aspects, the at least one second heat generating unit 640 comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger.

[0083] According to some aspects, a rear surface of the printed circuit board 620 and / or a rear surface of the at least one second heat generating unit 640 forms part of the wall of the fluid conduction system 650 so that the liquid 655 is in direct contact with the rear surface of the printed circuit board 620 and / or the at least one second heat generating unit 640. According to some aspects, the PCB 620 and / or at least one second heat generating unit 640 is attached to a designated opening of the wall of the fluid conduction system by means of a mount plate, with a fluid tight seal between the PCB and / or at least one second heat generating unit and the mount plate.

[0084] According to some aspects, the fluid conduction system 650 further comprises a liquid cooling plate, and wherein a rear surface 621 of the printed circuit board 620 and / or wherein the at least one second heat generating unit 640 is in contact with the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the rear surface and / or the at least one second heat generating unit 640 to the liquid 655 used within the fluid conduction system 650.

[0085] According to some aspects, a rear surface of the at least one second heat generating unit 640 forms part of the wall of the pump 660 so that the liquid 655 is in direct contact with the rear surface of the at least one second heat generating unit 640.

[0086] According to some aspects, at least one of the at least one second heat generating unit 640 comprises a heat generating component, and wherein the heat generating component is in contact with a liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component to the liquid 655 used within the fluid conduction system 650.

[0087] According to some aspects, at least one of the at least one second heat generating unit 640 comprises a heat generating component 642, and wherein the heat generating component 642 is thermally connected to a liquid cooling plate via a metal sheet arranged between the heat generating component and the liquid cooling plate. The liquid cooling plate is arranged to transfer heat from the heat generating component via the metal sheet to the liquid 655 used within the fluid conduction system 650.

[0088] According to some aspects, at least one of the at least one second heat generating unit 640 comprises a heat generating component 642, and wherein the heat generating component 642 is arranged so that the liquid 655 is in direct contact with the heat generating component.

[0089] According to some aspects, a rear surface of the at least one second heat generating unit 640 forms part of the wall of the heat exchanger so that the liquid 655 is in direct contact with the rear surface of the at least one second heat generating unit 640.

Claims

CLAIMS1 . Lighting device (100, 200, 300, 400, 500, 600) comprising: at least one printed circuit board (120, 220, 320, 420, 520, 520), PCB, at least one holding at least one light-emitting diode (130, 230, 330, 430, 530, 630), LED, at least one second heat generating unit (140, 240, 340, 440, 540, 640), a fluid conduction system (150, 250, 350, 450, 550, 650) arranged to conduct liquid (155, 255, 355, 455, 555, 655), wherein the fluid conduction system (150, 250, 350, 450, 550, 650) is arranged for cooling both the at least one printed circuit board (120, 220, 320, 420, 520, 620) holding the at least one LED (130, 230, 330, 430, 530, 630) and the at least one second heat generating unit (140, 240, 340, 440, 540, 640), and a pump (160, 260, 360, 460, 560, 660) arranged to circulate said liquid (155, 255, 355, 455, 555, 655) through said fluid conduction system (150, 250, 350, 450, 550, 650), wherein the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises LED driving electronics, for example comprising an LED driver and an AC / DC converter, the LED driving electronics being configured to power and / or control the at least one LED of the at least one printed circuit board.

2. Lighting device (100, 200, 300, 400, 500, 600) according to claim 1 , wherein a rear surface (221 , 521 , 621) of the printed circuit board (120, 220, 320, 420, 520, 620) and / or a rear surface (441 , 541 , 641) of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) forms part of the wall of the fluid conduction system (150, 250, 350, 450, 550, 650) so that the liquid (155, 255, 355, 455, 555, 655) is in direct contact with the rear surface (221 , 521 , 621) of the printed circuit board (120, 220, 320, 420, 520, 620) and / or the at least one second heat generating unit (140, 240, 340, 440, 540, 640).

3. Lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein the fluid conduction system (150, 250, 350, 450, 550, 650) further comprises a liquid cooling plate (352, 452, 652), and wherein a rear surface (221 , 521 , 621) of the printed circuit board (120, 220, 320, 420, 520, 620) and / or the at least one second heat generating unit (140, 240, 340, 440, 540, 640) is in contact with the liquid cooling plate (352, 452, 652), the liquid cooling plate (352, 452, 652) being arranged to transfer heat from the rear surface (221 , 521 , 621) and / or the at least one second heat generating unit (140, 240, 340, 440, 540, 640) to the liquid (155, 255, 355, 455, 555, 655) used within the fluid conduction system (150, 250, 350, 450, 550, 650).

4. Lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein a rear surface (641) of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) forms part of the wall of the pump (160, 260, 360, 460, 560, 660) so that the liquid (155, 255, 355, 455, 555, 655) is in direct contact with the rear surface (641) of the at least one second heat generating unit (140, 240, 340, 440, 540, 640).

5. Lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein at least one of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises a heat generating component (642), and wherein the heat generating component (642) is in contact with a liquid cooling plate (352, 452, 652), the liquid cooling plate (352, 452, 652) being arranged to transfer heat from the heat generating component (642) to the liquid (155, 255, 355, 455, 555, 655) used within the fluid conduction system (150, 250, 350, 450, 550, 650).

6. Lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein at least one of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises a heat generating component (642), and wherein the heat generating component (642) is thermally connected to a liquid cooling plate (352, 452, 652) via a metal sheet (653) arranged between the heat generating component (642) and the liquid cooling plate (352, 452, 652), the liquid cooling plate (352, 452, 652) being arranged to transfer heat from the heat generating component (642) via the metal sheet (653) to the liquid (155, 255, 355, 455, 555, 655) used within the fluid conduction system (150, 250, 350, 450, 550, 650).

7. Lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein the fluid conduction system (150, 250, 350, 450, 550, 650) further comprises a heat exchanger (670) arranged to cool the liquid (155, 255, 355, 455, 555, 655).

8. Lighting device (100, 200, 300, 400, 500, 600) according to claim 7, wherein a rear surface (641) of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) forms part of the wall of the heat exchanger (670) so that the liquid (155, 255, 355, 455, 555, 655) is in direct contact with the rear surface (641) of the at least one second heat generating unit (140, 240, 340, 440, 540, 640).

9. The lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises power electronics and / or a motor and / or a transformer for fans.

10. The lighting device (100, 200, 300, 400, 500, 600) according to any of claims 7-9, wherein the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises power electronics and / or a motor and / or a transformer for fans of the heat exchanger (670).

11. The lighting device (100, 200, 300, 400, 500, 600) according to any of the preceding claims, wherein the at least one printed circuit board (120, 220, 320, 420, 520, 520) and / or a printed circuit board of the at least one second heat generating unit (140, 240, 340, 440, 540, 640) comprises a metal core printed circuit board, MC-PCB.

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