MODULAR STRUCTURE OF AN LED LIGHT

Description

[0001] The present invention relates to the modular construction of a luminaire, in particular an interior luminaire for illuminating workplaces, which has several separately designed components that are aligned with each other in the luminaire.

[0002] Luminaires are preferably designed with a modular construction because this allows for the use of identical modules in the design of various luminaires. The components can include, in particular, LED modules, which contain one or more LEDs (Light Emitting Diodes, which here refers to any type of semiconductor light source), reflectors, and lenses, manufactured from various materials and using different processes. However, these different materials have different coefficients of thermal expansion. When heated, the positioning of the components relative to each other can therefore shift. This shift should ideally have as little impact as possible on the optical system of the luminaire. Furthermore, the differential expansion of the components during operation can also cause noise, which is particularly undesirable for interior lighting in office applications.

[0003] Nevertheless, modularity is crucial for luminaires from a cost-design perspective. Using identical modules allows for a wide variety of luminaire designs. Such a diversity of options would necessitate significantly higher tooling investments in single-piece luminaires. However, the visible design of the luminaire variants should ideally appear seamless, meaning it should not be apparent that the system is composed of multiple identical modules. Furthermore, for automated production, the assembly of components within the luminaire should be as simple as possible. Finally, for sustainability reasons, it is also advantageous if the luminaire components can be easily separated and recycled.

[0004] EP 2 871 407 A1 discloses a luminaire according to the preamble of claim 1.

[0005] The object of the present invention is therefore to provide a modularly constructed luminaire which is easy to assemble and which, despite thermal expansion of the module components, prevents optical defects and noise generation during operation of the luminaire as far as possible.

[0006] The problem is solved by a luminaire, in particular an indoor luminaire for office applications, according to claim 1.

[0007] The luminaire according to the invention comprises at least one mounting bracket, an LED module, a lens element, and a reflector. These components are designed separately and mechanically connected within the luminaire. However, the mechanical connection does not involve any material bonding. This means that the parts can also be separated from one another without damage. A special feature of the luminaire according to the invention lies in the design of the positive-locking connections, which align the individual components within the luminaire relative to one another. A first positive-locking connection between the LED module and the mounting bracket positions the LED module relative to the mounting bracket in a longitudinal and transverse direction of the mounting bracket. The terms longitudinal and transverse direction always refer to the dimensions of the mounting bracket. However, if the mounting bracket has a square shape, the terms longitudinal and transverse direction are interchangeable.The lens element and the reflector are aligned relative to each other through a positive-locking mechanism. This second positive-locking connection ensures that the lens element and the reflector directly interlock and is particularly helpful because the lens element and the reflector have a significant influence on the optical properties of the system. These two components should therefore be aligned as precisely as possible, which is achieved through their interlocking design. Furthermore, a third positive-locking connection is provided between the LED module and the reflector. Since the alignment of the LED module relative to the reflector also has a significant impact on the optical quality of the luminaire, this positive-locking connection is advantageous. Finally, the reflector is designed to snap into the mounting bracket. This secures the entire luminaire assembly.This eliminates the need for a direct connection between the LED module or lens element and the device carrier.

[0008] According to a preferred embodiment, there is no direct positive fit between the LED module and the lens element. On the contrary, it is even advantageous that the lens element is freely movable relative to the LED module. The LED module generates heat during operation, which can be transferred to the adjacent components. To avoid stresses between the LED module and an adjacent lens, it is therefore advantageous if the lens can move relative to the LED module. This has no significant impact on the optical quality of the luminaire; small tolerances in the position between the lens element and the light source are acceptable in the LED module because a displacement of an LED relative to the optical axis of a large-area lens has only a very minor effect on the light distribution produced by the lens. Furthermore, the LED module and the lens element are indirectly aligned with each other via the three positive fits mentioned above.

[0009] According to a preferred embodiment, the reflector is snapped into the mounting bracket in an insertion direction that exerts a holding force on the lens element and / or the LED module in the direction of the mounting bracket, thus securing the lens element and / or the LED module in the luminaire. This allows the snap-fit ​​connection between the reflector and the mounting bracket to also be used to indirectly secure the lens element and the LED module to the mounting bracket without additional components. Since the precise alignment of the lens element and the LED module with respect to the mounting bracket is irrelevant to the optical properties of the luminaire, these components do not require a separate connection to the mounting bracket. Furthermore, the pressing action allows the LED module to be pressed flat against the mounting bracket, thus ensuring good thermal contact between the mounting bracket and the LED module.This has the advantage that the device carrier can also serve as a heat sink for the LED module, without the need for separate fastening means to firmly connect the LED module directly to the device carrier.

[0010] According to a further development of the aforementioned embodiment, the reflector exerts the holding force on the lens element only via one or more point contacts. The point contacts serve to reduce noise (stick-slip effect) that can occur due to the different thermal expansion rates between the reflector and the lens element. Both components are aligned relative to each other by the third form-fit connection. Nevertheless, when heated, the two components can shift longitudinally relative to each other. Such a shift in a direction perpendicular to a contact force can, however, lead to noise generation because the two pressed-together surfaces no longer slide smoothly over each other. One surface remains in contact with the other due to the contact force until the thermal stress is so great that the static friction is overcome, and the surfaces then move abruptly relative to each other.This creates a frictional vibration that is audibly perceptible and particularly bothersome in interior lighting. In the embodiment with point contact between the pressed components, the effect of the frictional vibration is prevented because there are no larger surface areas that are pressed together with a compressive force.

[0011] According to a preferred embodiment, the reflector has a touch guard which, together with the lens element, prevents the insertion of an elongated object with a diameter of at least 3 mm into the LED module in the area of ​​the LED module's conductor tracks. The touch guard can, for example, have a continuous surface on the end faces of the reflector, so that no gaps are formed in the luminaire that would allow access to the electrical conductors in the LED module with a gap width of more than 3 mm. This prevents a thin metallic object, such as a screwdriver or a piece of wire, from coming into contact with live parts of the luminaire in the event of improper maintenance. Since the corresponding components of the luminaire according to the invention are already connected to each other by positive locking, the additional touch guard increases the operational safety of the luminaire without significant effort.Furthermore, this embodiment also has the advantage that a visually uniform appearance of the luminaire is achieved.

[0012] According to a preferred embodiment, the reflector is designed as part of a luminaire grid that has inner walls, each surrounding one of several light emission openings of the luminaire. Preferably, at least one LED of the LED module is assigned to each light emission opening. Luminaire grids with reflective inner walls are preferred in applications as interior luminaires because of the improved glare control. However, the inner walls can also be light-absorbing. The modular design according to the invention can be applied very easily to this type of luminaire because the luminaire grid, which provides the reflective surfaces of the reflector, can be arranged above the lens element. In this embodiment, the lens element can comprise several individual lenses, each arranged in a light emission opening of the luminaire grid and held in place by the aforementioned positive locking mechanism.Preferably, however, the individual lenses are also combined in one or more larger, preferably plate-shaped, lens elements, so that the lens element extends over several light exit openings of the light grid and is positively connected to it.

[0013] According to a preferred embodiment, the first positive locking mechanism is formed by a protruding positioning element on the device carrier that engages in a recess of the LED module. This engagement secures the LED module relative to the device carrier only in the longitudinal and transverse directions. This holds the LED module centrally on the device carrier. However, the LED module can still be slid onto the device carrier in the remaining free direction. Preferably, this free direction of movement corresponds exactly to the insertion direction of the snap-fit ​​connection between the reflector and the device carrier. This secures the LED module to the device carrier in all directions in conjunction with the reflector. A direct connection between the reflector and the LED module is not necessary. It is sufficient if the LED module is held indirectly on the device carrier perpendicular to the transverse and longitudinal directions by the contact force of the reflector and the lens element.

[0014] According to a preferred embodiment, the third form-fit connection is formed by interlocking positioning elements on the LED module and the reflector, which fix the reflector relative to the LED module along a transverse direction of the device carrier. In this embodiment, the reflector can expand relative to the LED module in the longitudinal direction of the device carrier. This prevents thermal stresses in the luminaire, while still keeping the reflector centered relative to the LED module.

[0015] According to the invention, the second positive locking mechanism is formed by a projecting rib of the lens element that engages in a groove of the reflector, the engagement fixing the reflector relative to the lens element only along a transverse direction. This embodiment is particularly preferred for longer reflectors, e.g., in a grid lamp with several grids arranged one behind the other and small transverse dimensions. Thermal stresses between the lens element and the reflector are prevented by allowing the reflector to extend in the longitudinal direction of the lens element or the device carrier, with the lens element being held centered relative to the reflector transversely to the longitudinal extent of the lamp.

[0016] According to a preferred embodiment, the reflector has several elastic locking lugs on opposite side walls of the reflector for snapping into the device carrier. These lugs engage in a corresponding number of recesses on two opposite sides of the device carrier. It is particularly advantageous that the locking lugs are provided on two opposite side walls of the reflector or the device carrier because this centers the reflector in the device carrier and allows the reflector to be inserted perpendicular to the transverse and longitudinal extent of the device carrier, in the direction of the lens element and the LED module.In this embodiment, a downward pressure force on the lens element and the LED module can therefore be generated very easily by snapping the reflector into place, in order to indirectly hold all other components on the device carrier without the need for a direct force-fit connection between the device carrier and the LED module or the lens element.

[0017] Further advantages and features of the present invention will become clear from the following description of a preferred embodiment, which is given in conjunction with the accompanying figures. The figures illustrate the following: Figure 1 shows a perspective view of a luminaire according to one embodiment. Figure 2 shows an exploded side view of the luminaire. Figure 3 shows an enlarged perspective view of the luminaire. Figure 4 shows a side view of the luminaire. Figure 5 shows a cross-section through the luminaire. Figure 6 shows a cross-section of an enlarged section of the luminaire without the mounting bracket. Figure 7 shows a top view of an enlarged section of the luminaire's reflector.

[0018] The luminaire in the illustrated embodiment comprises a mounting bracket 2 in which an LED module 3, a lens element 4, and a reflector 5, which is designed as a luminaire grid, are arranged. The mounting bracket 2 has an approximately U-shaped cross-section perpendicular to its longitudinal extent. Preferably, the mounting bracket is made of a metal sheet. The LED module 3 rests flat on the inside of the base of the U-shaped mounting bracket 2. The LED module 3 comprises a circuit board on which several LEDs are arranged in a row and electrically contacted. The LED module 3 is simply inserted into the mounting bracket from below and is held in place by being pressed down on the base of the mounting bracket 2 by the reflector 5 and the lens element 4. As, for example, in the Figure 1As shown, the reflector 5 is inserted into the mounting bracket and engaged by locking lugs 54 on the side walls of the reflector 5 in recesses 21 in the side walls of the U-shaped mounting bracket 2. The reflector 5 is engaged by a movement perpendicular to the planar extent of the LED module 3 towards the base of the mounting bracket 2. Before the reflector 5 is engaged in the mounting bracket 2, however, the lens element 4 is inserted into the reflector 5. This causes the reflector 5, with the lens element 4, to press against the LED module 3, thereby holding all components of the luminaire in the mounting bracket 2.

[0019] The LED module 3 is positioned on the device carrier 2. For this purpose, recesses 30 are provided on the long sides of the LED module, which engage in corresponding projections 20 on the device carrier, such as in Figure 5The interlocking of the positioning elements 20 with the recesses 30 secures the LED module longitudinally and transversely relative to the device carrier. However, the LED module is merely inserted into the device carrier and not directly rigidly connected to it perpendicular to the transverse and longitudinal directions, but is only held by the reflector or the lens element 4. The interlocking of the positioning elements 20 with the recesses 30 is also referred to as the first positive-locking connection in this application.

[0020] The lens element 4 has a positioning element in the form of a bridge 41, and the reflector 5 has a positioning element in the form of a groove-shaped recess 53. As shown on the front of the luminaire in the figure below. Figure 3As can be seen, the lens element 4 engages with the rib 41 in the groove 53 of the reflector 5. This secures the lens element in the transverse direction to the reflector. The positive locking between the rib 41 and the groove 53 is also referred to as the second positive locking in this application.

[0021] For the alignment of the LED module 3 with the reflector 5, the reflector has positioning elements 51 which engage in recesses 32 of the LED module 3, as shown in Figure 5 This positive fit between the recess 32 on the LED module 3 and the positioning element 51 on the reflector 5 is also referred to as the third positive fit in this application.

[0022] Finally, to mount the light, the reflector 5 with the lens element 4 is snapped into the device carrier 2, clamping the LED module 3 to the base of the device carrier 2.

[0023] The central fixings 31, 30, 52, and 40 serve to position the components in the middle. This allows the longitudinal expansion of the different components to flow outwards. Sufficient clearance is provided at the outer fixings 32 and 51 to prevent contact even during thermal expansion.

[0024] Referring to the Figure 7The figure also shows how the reflector 5 is designed to exert the force required to hold down the lens element 4 and the LED module 3. The reflector 5 has almost point-like protrusions 56 in the area of ​​two opposing edges, which form contact with the underlying component. Because only point-like contacts are formed in the direction of the holding force, no flat sections are pressed against each other. This serves to reduce noise (stick-slip effect) that could arise from the heating of components in contact over a flat area. The small contact area ensures that the stick-slip effect is reduced as much as possible when the locking hooks 54 are engaged in the recesses 21 of the device carrier.

[0025] Furthermore, in the illustrated embodiment, a contact guard 55 is provided on the reflector 5, which completely fills the area up to the LED module 3 on one end face of the reflector, as shown in Figure 4 As shown, the LED module 3 cannot be touched even by a narrow object, such as a screwdriver, because it is completely enclosed. However, this touch protection is only necessary in the area of ​​the circuit trace of the LED module 3, and if no circuit trace is provided on the front of the LED module 3, the front of the LED module 3 can protrude.

[0026] The luminaire described above is shown in an elongated version, with the reflector 5 depicted as a single row of luminaire grids, each enclosing a small light-emitting surface. In other embodiments, however, the luminaire can also be wider. For example, two or more grids can be arranged side by side in the transverse direction to the longitudinal extent of the luminaire. In other embodiments, the luminaire can also have a square cross-section. In this case, the longitudinal and transverse dimensions are equal.

[0027] According to the embodiment of the luminaire, the gear carrier 2 can be mounted in a housing. For this purpose, for example, retaining springs 6 are provided on the outer side of the gear carrier 2, which can be snapped into recesses in a housing (not shown in the figures). For example, several gear carriers can also be snapped into the housing one behind the other or side by side to create modular luminaires with different longitudinal and transverse dimensions. REFERENCE MARK LIST

[0028] 2 Equipment carrier 3 LED module 30 Positioning to equipment carrier 31 Positioning transverse and longitudinal 32 Positioning transverse 4 Lens element 40 Positioning longitudinal / transverse 41 Bridge for positioning transversely 5 Reflector 51 Positioning transversely 52 Positioning transversely / longitudinal 53 Groove for positioning transversely 54 Locking lug 55 Touch guard 56 Point support 6 Mounting spring on equipment carrier

Claims

1. Luminaire having at least: - a device carrier (2), - an LED module (3), - a lens element (4), and - a reflector (5), which are all formed as separate components and are mechanically connected in the luminaire, wherein the reflector (5) is latched into the device carrier (2), wherein the LED module (3) bears against the device carrier (2) by a first form fit and the first form fit positions the LED module in a longitudinal and transverse direction on the device carrier (2), wherein the lens element (4) and the reflector (5) engage in one another by a second form fit and the second form fit only aligns the lens element (4) and the reflector (5) with respect to one another, wherein the second form fit is formed by a projecting web (41) of the lens element (4), which engages in a groove (53) of the reflector (5), wherein the engagement fixes the reflector (5) with respect to the lens element (4) only along a transverse direction, and the LED module (3) is aligned with respect to the reflector (5) by a third form fit.

2. Luminaire according to Claim 1, wherein no direct form fit is formed between the LED module (3) and the lens element (4).

3. Luminaire according to one of the preceding claims, wherein the reflector (5) is latched into the device carrier (2) in an insertion direction which exerts a hold-down force on the lens element (4) and / or the LED module (3) in a direction towards the device carrier (2), in order to hold the lens element (4) and / or the LED module (3) in the luminaire.

4. Luminaire according to Claim 3, wherein the reflector (5) exerts the hold-down force on the lens element (4) only with one or more point supports (56).

5. Luminaire according to one of the preceding claims, wherein the reflector (5) has a contact protection (55) which, together with the lens element (4), prevents an elongated object with a diameter of at least 3 mm from being introduced to the LED module at least in the region of conductor tracks of the LED module.

6. Luminaire according to one of the preceding claims, wherein the reflector (5) is designed as part of a luminaire grid which has inner walls which each surround one of a plurality of light exit openings of the luminaire, wherein preferably in each case at least one LED of the LED module (3) is assigned to one of the light exit openings.

7. Luminaire according to one of the preceding claims, wherein the first form fit is formed by a projecting positioning element (20) on the device carrier (2), which engages in a cutout (30) of the LED module (3), wherein the engagement fixes the LED module (3) with respect to the device carrier (2) only in the longitudinal and transverse direction.

8. Luminaire according to one of the preceding claims, wherein the third form fit is formed by positioning elements (32, 51) which engage in one another on the LED module (3) and the reflector (5) and which fix the reflector (5) with respect to the LED module (3) with respect to one another along a transverse direction of the device carrier (2).

9. Luminaire according to one of the preceding claims, wherein the reflector (5) has, for latching the reflector (5) into the device carrier (2), a plurality of elastic latching lugs (54) on opposite side walls of the reflector (5), which latching lugs are latched into a corresponding number of cutouts (21) on two opposite sides of the device carrier (2).