A light emitting device with variable light beam angle

Abstract

A light emitting device (1; 101; 102; 103) comprising a plurality of LEDs (2) adapted for, in operation, emitting light in a main direction of emission (E), and being arranged along a longitudinal axis (L) of an elongated substrate (3), and a translucent, elastically deformable housing (4) enclosing the plurality of LEDs (2) and the elongated substrate (3) and comprising a length direction (X) extending in parallel with the longitudinal axis (L), a height direction (Y) extending in parallel with the main direction of emission (E) and a width direction (Z) extending perpendicular to both the length and height direction (X, Y), wherein the housing (4) further comprises an elongated cavity (5) arranged downstream of the plurality of LEDs (2) as seen in the main direction of emission (E) and extending in parallel with the length direction (X), the elongated cavity (5) comprising a first surface part (6), a second surface part (7), a third surface part (8) and a fourth surface part (9), where the first and second surface part (6, 7) are mutually opposite surface parts as seen in the height direction (Y), and where the third and fourth surface part (8, 9) connect the first and second surface part (6, 7), a recess (10) provided in one of the first and second surface part (6, 7), and a protrusion (11) provided on the other one of the first and second surface part (6, 7), the recess (10) and the protrusion (11) being configured for mutual, releasable engagement by elastic deformation of the housing (4).

Description

[0001] A light emitting device with variable light beam angle

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a light emitting device comprising a plurality of LEDs adapted for, in operation, emitting light in a main direction of emission, E, an elongated substrate, the plurality of LEDs being arranged along a longitudinal axis, L, of the elongated substrate, and a translucent, elastically deformable housing enclosing the plurality of LEDs and the elongated substrate at least partially and comprising a length direction, X, extending in parallel with the longitudinal axis, L, a height direction, Y, extending in parallel with the direction of emission, E, and a width direction, Z, extending perpendicular to both the length direction, X, and the height direction, Y.

[0004] BACKGROUND OF THE INVENTION

[0005] LED strips enclosed in flexible silicone housing are commonplace and used extensively. For instance, the LED strip known and sold under the name Hue comprises a flexible LED strip with silicone cover. Such LED strips are commonly used to illuminate areas underneath cupboards or behind sofas etc. and are typically more decorative than functional. They are connected to a power source and are typically affixed to an area using adhesive tape or in some cases an aluminum enclosure.

[0006] When placing such a LED strip on the back of a piece of furniture, the area of the wall illuminated behind the piece of furniture is currently dictated by the distance to the wall. This means consumers often move their furniture slightly away from the wall to achieve a desired, nice effect.

[0007] US 11,193,653 Bl discloses a linear LED lighting system with a deformable optic intended for producing light beams having variable beam angles. Deformation of the optic is obtained by means of a deformation mechanism including a first plate and a second plate being movable with respect to each other. Actuation of the deformation mechanism is caused by rotation of one or both end cap assemblies of the LED lighting system.

[0008] However, this solution is still both complex in the construction and cumbersome for the end user to operate, especially after the LED strip has been mounted on a piece of furniture. Thus, and further since furniture differs in size and shape, there is still a desire to provide to the consumer a LED strip with a switching capability which would allow them to mechanically select the beam shape, and particularly the beam angle, they prefer.

[0009] Especially, there is a desire to provide such a LED strip which furthermore is simple in construction, simple to manufacture and easy for the end user to operate, especially after the LED strip has been mounted on a piece of furniture.

[0010] SUMMARY OF THE INVENTION

[0011] It is an object of the present invention to overcome this problem, and to provide to the consumer a LED strip with a switching capability which would allow them to mechanically select the beam shape, and particularly the beam angle, they prefer.

[0012] It is a further object of the invention to provide a LED strip which furthermore is simple in construction, simple to manufacture and easy for the end user to operate, especially after the LED strip has been mounted on a piece of furniture.

[0013] According to a first aspect of the invention, this and other objects are achieved by means of a light emitting device comprising a plurality of LEDs adapted for, in operation, emitting light in a main direction of emission, E, an elongated substrate, the plurality of LEDs being arranged along a longitudinal axis, L of the elongated substrate, and a translucent, elastically deformable housing enclosing the plurality of LEDs and the elongated substrate at least partially and comprising a length direction, X extending in parallel with the longitudinal axis, L, a height direction, Y, extending in parallel with the main direction of emission, E, and a width direction, Z, extending perpendicular to both the length direction, X, and the height direction, Y, where the housing further comprises an elongated cavity arranged downstream of the plurality of LEDs as seen in the main direction of emission, E, and extending in parallel with the length direction, X, the elongated cavity comprising a first surface part, a second surface part, a third surface part and a fourth surface part, where the first surface part and the second surface part are mutually opposite surface parts as seen in the height direction, Y, and where the third surface part and the fourth surface part connect the first surface part and the second surface part, a recess provided in one of the first surface part and the second surface part, and a protrusion provided on the other one of the first surface part and the second surface part, and where the recess and the protrusion are configured for mutual, releasable engagement by elastic deformation of at least a part of the housing.

[0014] Thereby, and in particular by providing a housing with a cavity, a recess and a protrusion as described above, and in particular by providing that the recess and the protrusion are configured for mutual, releasable engagement by elastic deformation of at least a part of the housing, a light emitting device, optionally in the form of a LED strip, is provided with a switching capability which allows the user or consumer to mechanically select the beam shape, and particularly the beam angle, they prefer.

[0015] This may also allow the user or consumer to mechanically select other properties related to the beam shape, such as the gradient of or light effects in the resulting beam. It is noted that in this case it may also, in order to obtain the desired effect, be necessary to add further beam altering elements to the light emitting device, particularly to the housing. Such further beam altering elements may for instance include shaping the housing and embedding in the housing one or more of diffractive elements, refractive elements and scattering elements, possibly in a predetermined pattern.

[0016] Such a light emitting device is furthermore is simple in construction, simple to manufacture and easy for the end user or consumer to operate, especially after the light emitting device has been mounted on a piece of furniture.

[0017] The recess and the protrusion may be configured for being movable between a released position and an engaged position by elastic deformation of at least a part of the housing.

[0018] Thereby, the light emitting device is provided with a switching capability which is furthermore non-destructive and may be used several times.

[0019] The cavity, the recess and the protrusion may be constructed such that the light emitted by the plurality of LEDs propagates through the cavity in the released position of the recess and the protrusion, and such that at least a part of the light emitted by the plurality of LEDs does not propagate through the cavity in the engaged position of the recess and the protrusion.

[0020] Thereby, the light emitting device is provided with a switching capability providing two different beam shapes in a particularly simple manner, namely by exploiting the inherent difference in refractive index between the material of the housing and the gas, normally being air, filling the cavity.

[0021] The protrusion may be configured to, in the released position, be arranged with a free end located at a mouth of the recess or at a level of the one of the first surface part and the second surface part in which the recess is provided.

[0022] Thereby, it is ensured that the above advantages are achieved while also ensuring that the light emitting device is compact and takes up a minimum of space both during transport and storage and when mounted at the consumer. The recess may be provided centrally in one of the first surface part and the second surface part as seen in the width direction, Z, and the protrusion may be provided centrally on the other one of the first surface part and the second surface part as seen in the width direction, Z.

[0023] Thereby, the recess and the protrusion are arranged in the main direction of emission, E, of the plurality of LEDs. This in turn ensures that especially the inherent difference in refractive index between the material of the housing and the gas, normally being air, filling the cavity may be exploited in a structurally particularly simple manner.

[0024] The elongated cavity may be continuous in the length direction, X, and the recess and the protrusion may be continuous in the length direction, X.

[0025] Thereby, the two different beam widths may be obtained continuously over the whole length of the light emitting device, which in turn ensures a uniform light output over the length of the light emitting device.

[0026] The size of the recess as measured in the height direction, Y, may be within 2 mm of the size of the cavity as measured in the height direction, Y.

[0027] The size of the recess as measured in the height direction, Y, may equal the size of the cavity as measured in the height direction, Y.

[0028] This in turn ensures that especially the inherent difference in refractive index between the material of the housing and the gas, normally being air, filling the cavity may be exploited in a particularly efficient manner.

[0029] The size of the recess as measured in the width direction, Z, may be equal to or larger than the size of the LEDs of the plurality of LEDs as measured in the width direction, Z.

[0030] Thereby, it is ensured that a vast majority of the light emitted by the plurality of LEDs propagates through the cavity and recess, thereby ensuring that especially the inherent difference in refractive index between the material of the housing and the gas, normally being air, filling the cavity may be exploited in a particularly efficient or even an optimal manner.

[0031] The recess and the protrusion may be configured for snap-locking or frictionlocking mutual, releasable engagement.

[0032] Thereby a recess and a protrusion is provided which is particularly easy for the user or consumer both to bring into engagement and to release from engagement when or if it is desired. The housing may comprise a body part enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part of the cavity, a top part comprising the second surface part of the cavity and two side parts connecting the body part and the top part, where the recess and the protrusion are configured to be brought into mutual engagement by pressing a section of the top part towards the body part in a direction, A, parallel with the height direction, Y.

[0033] Thereby, it is ensured that bringing the recess and the protrusion into engagement is made both very simple and intuitive for the user or consumer.

[0034] The section of the top part may be a section of the top part being in direct connection with the recess or the protrusion. The section of the top part may be a central section of the top part as seen in the width direction, Z.

[0035] Thereby, it is ensured that bringing the recess and the protrusion into engagement is made particularly intuitive for the user or consumer.

[0036] The housing may comprise a body part enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part of the cavity, a top part comprising the second surface part of the cavity and two side parts connecting the body part and the top part, where the recess and the protrusion are configured to be released from mutual engagement by one or more of pressing the two side parts towards each other in a direction B or C perpendicular to the height direction, Y, and pressing the two side parts away from each other by pressing on the top part in a direction, D, forming an angle, 6, of more than 45 degrees and less than 90 degrees with the height direction, Y.

[0037] Thereby, it is ensured that releasing the recess and the protrusion from engagement is made both very simple and intuitive for the user or consumer.

[0038] The housing may comprise a body part enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part of the cavity, a top part comprising the second surface part of the cavity and two side parts connecting the body part and the top part, and the light emitting device may further comprise a first lens element and a second lens element, wherein the first lens element forms a part of the top part of the housing, and wherein the second lens element forms a part of the body part of the housing.

[0039] Thereby, the two (or more) different beam widths may be obtained by further exploiting the inherent light modifying characteristics of the lenses chosen. The first lens element may be a rigid lens or semi rigid lens. The second lens element may be a rigid lens or a semi rigid lens.

[0040] Especially when at least one of the first lens element and the second lens element is a semi rigid lens element a sufficiently elastically deformable housing is ensured in a straight-forward manner, such that the above advantages may still be obtained in a simple manner.

[0041] The first lens element and the second lens element may, respectively, be one continuous lens as seen in the length direction, X.

[0042] Thereby, the two different beam widths may be obtained continuously over the whole length of the light emitting device, which in turn ensures a uniform light output.

[0043] Alternatively, the first lens element and the second lens element may, respectively, comprise a series or plurality of lenses arranged along the longitudinal axis, L, of the elongated substrate.

[0044] Thereby, the two different beam widths may still be obtained continuously over the whole length of the light emitting device, which in turn ensures a uniform light output. A further advantage in this case is that it becomes possible by way of the choice of lenses to provide the light emitted by each individual LED or sub-group of LEDs of the plurality of LEDs with two different customized beam widths.

[0045] The protrusion may be provided on one of the first lens element and the second lens element, and the recess may be provided in the other one of the second lens element and the first lens element.

[0046] Thereby a structurally particularly simple light emitting device is provided for.

[0047] The recess may comprise at least one engagement structure and the protrusion may comprise a complementary engagement structure, the complementary engagement structure being complementary to the at least one engagement structure.

[0048] Such respective engagement structures provide for a more stable engagement between the recess and the protrusion.

[0049] The at least one engagement structure may be any one of an incision and a projection, and the complementary engagement structure is any one of a projection and an incision.

[0050] Thereby structurally particularly simple engagement structures are provided for.

[0051] The at least one engagement structure may be a continuous structure, and the complementary engagement structure may be a continuous structure. Thereby, a more stable engagement between the recess and the protrusion is ensured along the whole length of the light emitting device.

[0052] The at least one engagement structure may be a discontinuous structure, and the complementary engagement structure may be a discontinuous structure.

[0053] Thereby material may be saved while still ensuring a stable engagement between the recess and the protrusion.

[0054] The translucent housing may be a transparent housing.

[0055] The translucent housing may be made of silicone.

[0056] Silicone has been shown to provide a housing being simple to produce, such as by molding, durable, particularly as regards exposure to LED light, and sufficiently elastically deformable.

[0057] The cavity may be filled with gas, such as air, particularly atmospheric air or ambient air.

[0058] The invention further relates to a luminaire comprising at least one light emitting device according to the invention.

[0059] It is noted that the invention relates to all possible combinations of features recited in the claims.

[0060] BRIEF DESCRIPTION OF THE DRAWINGS

[0061] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

[0062] Fig. 1 shows a cross-sectional view of a light emitting device according to the invention and comprising a housing with an elongated cavity, a recess and a protrusion, the recess and the protrusion being shown in a released or disengaged position.

[0063] Fig. 2 shows a cross-sectional view of a light emitting device according to Fig.

[0064] 1 with the recess and the protrusion being shown in an engaged position.

[0065] Fig. 3 shows a cross-sectional view of a light emitting device according to Figs. 1 and 2 and illustrating operation to bring the recess and the protrusion from the released position to the engaged position.

[0066] Fig. 4 shows a cross-sectional view of a light emitting device according to Figs. 1 and 2 and illustrating operations to bring the recess and the protrusion from the engaged position to the released position.

[0067] Fig. 5 shows a cross-sectional view of a light emitting device according to another embodiment of the invention. Fig. 6 shows a cross-sectional view of a light emitting device according to yet another embodiment of the invention.

[0068] Fig. 7 shows a cross-sectional view of a light emitting device according to yet another embodiment of the invention.

[0069] Fig. 8 shows a schematical, cross-sectional view of a light beam obtained with a light emitting device according to the invention being in a state as illustrated, e.g., in Fig. 1.

[0070] Fig. 9 shows a schematical, cross-sectional view of a light beam obtained with a light emitting device according to the invention being in a state as illustrated, e.g., in Fig. 2.

[0071] Fig. 10 shows a cross-sectional view of a light emitting device according to yet another embodiment of the invention.

[0072] As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

[0073] DETAILED DESCRIPTION

[0074] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

[0075] Figs. 1 and 2 shows a cross-sectional view of a light emitting device 1 according to the invention. Generally, and irrespective of the embodiment, the light emitting device 1 comprises a plurality of LEDs 2, an elongated substrate 3 and a housing 4 enclosing the plurality of LEDs 2 and the elongated substrate 3.

[0076] The plurality of LEDs 2 are each adapted for, in operation, emitting light in a main direction of emission E. The plurality of LEDs 2 are arranged one the elongated substrate 3. The plurality of LEDs 2 are distributed along a longitudinal axis L of the elongated substrate 3. The plurality of LEDs 2 may, for instance, be white LEDs, red LEDs, green LEDs, blue LEDs or a mixture thereof.

[0077] The elongated substrate 3 comprises a longitudinal axis L. The elongated substrate 3 may for instance be a printed circuit board (PCB). The elongated substrate 3 may comprise wiring configured to provide the plurality of LEDs 2 with electrical energy. The housing 4 is a translucent, elastically deformable housing. By elastically deformable housing is to be understood that at least a part of the housing 4 is elastically deformable, thus not excluding that a part of the housing 4 may be rigid. The housing 4 encloses the plurality of LEDs 2 and the elongated substrate 3 partially or as shown in Figs. 1 and 2 fully. The housing 4 comprises a length direction, X, extending in parallel with the longitudinal axis L of the elongated substrate 3. The housing 4 comprises a height direction, Y, extending in parallel with the main direction of emission, E. The housing 4 comprises a width direction, Z, extending perpendicular to both the length direction, X, and the height direction, Y. The housing 4 further comprises an elongated cavity 5. The housing 4 further comprises a body part 12. The body part 12 may be the part of the housing 4 that at least partially encloses the plurality of LEDs 2 and the elongated substrate 3. The housing 4 further comprises a top part 13 and two side parts 14 and 15. The body part 12 comprises a first surface part 6 of the cavity 5. The top part 13 comprises a second surface part 7 of the cavity 5. The two side parts 14 and 15 comprise a third surface part 8 and a second surface part 9, respectively, of the cavity 5. The two side parts 14 and 15 connect the body part 12 and the top part 13. The housing 4 may be made of any suitable translucent and elastically deformable material. For instance, the housing 4 may be made of silicone, particularly an optical grade silicone.

[0078] The elongated cavity 5 is arranged downstream of the plurality of LEDs 2 as seen in the main direction of emission E. The elongated cavity 5 extends in parallel with the length direction, X. The elongated cavity 5 comprises a first surface part 6, a second surface part 7, a third surface part 8 and a fourth surface part 9. The first surface part 6 and the second surface part 7 are mutually opposite surface parts as seen in the height direction, Y. The third surface part 8 and the fourth surface part 9 connect the first surface part 6 and the second surface part 7. In the embodiment shown the first surface part 6, the second surface part 7, the third surface part 8 and the fourth surface part 9 form an elongated cavity 5 having a rectangular cross-sectional shape. However, it is also feasible to provide an elongated cavity having another cross-sectional shape, such as round, oval, square or trapezoid.

[0079] The elongated cavity 5 further comprises a recess 10 provided in the first surface part 6 and a protrusion 11 provided on the second surface part 7. Alternatively, the recess 10 may be provided in the second surface part 7 and the protrusion 11 may be provided on the first surface part 6. The protrusion 11 comprises a free end 27 and the recess comprises an opening or a mouth 28. The elongated cavity 5 may be continuous in the length direction, X, and the recess 10 and the protrusion 11 may be continuous in the length direction, X.

[0080] Generally, and irrespective of the embodiment, the recess 10 and the protrusion 11 are configured for mutual, releasable engagement by elastic deformation of at least a part of the housing 4. More particularly, the recess 10 and the protrusion 11 are configured for being movable between a released position (Fig. 1) and an engaged position (Fig. 2) by elastic deformation of at least a part of the housing 4. The recess 10 and the protrusion 11 may be configured for snap-locking or friction-locking mutual, releasable engagement. Optionally, the recess 10 may further comprise an engagement structure 17 and the protrusion 11 may further comprise a complementary engagement structure 16. The engagement structures 16 and 17 are configured for mutual engagement in the engaged position of the recess 10 and protrusion 11.

[0081] The cavity 5, the recess 10 and the protrusion 11 are constructed and shaped such that the light emitted by the plurality of LEDs 2 propagates through the cavity 5 in the released position (Fig. 1) of the recess 10 and the protrusion 11, and such that at least a part of the light emitted by the plurality of LEDs 2, and particularly the part of the light emitted in the main direction of emission, E, or a direction close thereto, does not propagate through the cavity 5, but rather through the housing 4, in the engaged position (Fig. 2) of the recess 10 and the protrusion 11.

[0082] For instance, when in the released position (Fig. 1), the protrusion 11 may be configured to be arranged with the free end 27 located at the mouth 28 of the recess 10, or with the free end 27 arranged at a level of the one of the first surface part 6 and the second surface part 7 in which the recess 10 is provided.

[0083] Since the refractive index of the gas, such as most often atmospheric air or ambient air, filling the cavity 5 and the refractive index of the material of the housing 4 are different from one another, different beam shapes are obtained in this way.

[0084] The recess 10 may be provided centrally in the first surface part 6 as seen in the width direction Z and the protrusion 11 may be provided centrally on the second surface part 7 as seen in the width direction Z. The size of the recess 10 as measured in the height direction Y may be within 2 mm of the size of the cavity as measured in the height direction Y. Alternatively, the size of the recess 10 as measured in the height direction Y may be equal to the size of the cavity 11 as measured in the height direction Y. Alternatively, or additionally, the size of the recess 10 as measured in the width direction, Z, may be equal to or larger than the size of the LEDs of the plurality of LEDs 2 as measured in the width direction, Z.

[0085] Referring now also to Fig. 3, the recess 10 and the protrusion 11 may be brought into mutual engagement, that is be brought to the engaged position (Fig. 2), by pressing a section 29 of the top part 13 towards the body part 12 in a direction A being parallel with the height direction Y. The section 29 of the top part 13 may be a section 29 of the top part 13 being in direct connection with the protrusion 11. Alternatively, or additionally, the section 29 of the top part 13 may be a central section of the top part 13 as seen in the width direction Z.

[0086] Referring now also to Fig. 4, the recess 10 and the protrusion 11 may be released from mutual engagement, that is brought to the released position (Fig. 1) in one of three different ways. Either by pressing the two side parts 14 and 15 towards each other in a direction B being perpendicular to the height direction Y. Alternatively, by pressing an upper part, that is a part adjacent to the cavity 5, of the body part 12 inwards in a direction C being perpendicular to the height direction Y. Alternatively, by pressing the two side parts 14 and 15 away from each other (arrows G) by pressing on the top part 13 in a direction D forming an angle 6 of more than 45 degrees and less than 90 degrees with the height direction Y.

[0087] Figs. 8 and 9 illustrate schematically two beams 25 and 26, respectively, obtainable with a light emitting device according to any embodiment of the invention. In each case a light emitting device 1 is mounted on the back of a piece of furniture 23, such as a cupboard, and used to illuminate a wall 24 adjacent to the piece of furniture 23. The distance between the piece of furniture 23 and the wall 24 is the same in each case.

[0088] Fig. 8 shows a schematical, cross-sectional view of a light beam 25 obtained with a light emitting device 1 according to the invention being in a released state as illustrated in Fig. 1 where the recess 10 and the protrusion 11 are in a disengaged or released position as described above. Fig. 9 shows a schematical, cross-sectional view of a light beam 26 obtained with a light emitting device 1 according to the invention being in an engaged state as illustrated, for instance, in Fig. 2, where the recess 10 and the protrusion 11 are in and engaged position as described above. As may be seen, when light emitting device 1 is in the engaged state, the beam 26 is broader as compared to the beam 25 obtained when the light emitting device 1 is in the released state. The beam 26 thus illuminates a larger area as compared to the beam 25 without the need for moving the piece 23 of furniture away from the wall 24. Turning now to Fig. 5, a cross-sectional view of a light emitting device 100 according to another embodiment of the invention is shown. The light emitting device 100 is shown in a released position of the recess 10 and the protrusion 11.

[0089] The light emitting device 100 of Fig. 5 differs from the light emitting device 1 of Figs. 1 and 2 described above in virtue of the feature that the recess 10 is provided in the second surface part 7 and the protrusion 11 is provided on the first surface part 6.

[0090] Turning now to Fig. 6, a cross-sectional view of a light emitting device 101 according to yet another embodiment of the invention is shown. The light emitting device 101 is shown in a released position of the recess 10 and the protrusion 11.

[0091] The light emitting device 101 of Fig. 6 differs from the light emitting devices

[0092] I and 100 of Figs. 1, 2 and 5 described above in virtue of comprising a recess 10 and a protrusion 11 having a different construction or structure. The protrusion 11 comprises a projection 20, and the recess 10 comprises an incision 21. The projection 20 and the incision 21 may be circumferential structures or partially circumferential structures. The projection 20 and the incision 21 form an engagement structure and a complementary engagement structure, respectively, for the same purpose as the engagement structure 16 and the complementary engagement structure 17 described above in relation to Figs. 1 and 2. The projection 20 and the incision 21 may be made of the same material as the housing 4 or of a material being more flexible than that of the housing 4. In any event, the material of the projection 20 and the incision 21 and the material of the housing 4 advantageously have the same or nearly the same refractive index. Thereby it may be ensured that the projection 20 and the incision 21 have minimal effect on the light output. In an alternative, the protrusion

[0093] I I may comprise an incision 21, and the recess 10 may comprise a projection 20.

[0094] Turning now to Fig. 7, a cross-sectional view of a light emitting device 102 according to another embodiment of the invention is shown. The light emitting device 102 is shown in a released position of the recess 10 and the protrusion 11.

[0095] The light emitting device 102 of Fig. 7 is very similar to the light emitting device 101 shown in Fig. 6 but differs therefrom in virtue of the following. Namely, the protrusion 11 comprises an incision 21, and the recess 10 comprises two projections 20 and 22. Thereby, it becomes possible to engage the protrusion 11 in the recess 10 in two different engaged positions corresponding to each of the two projections 20 and 22. This in turn provides for a light emitting device 102 which may provide three different beam shapes, particularly beam angles, namely corresponding to the released position and the two different engaged positions, respectively. Turning finally to Fig. 10, a cross-sectional view of a light emitting device 103 according to another embodiment of the invention is shown. The light emitting device 103 is shown in an engaged position of the recess 10 and the protrusion 11. The light emitting device 103 of Fig. 10 is similar to the light emitting device 1 shown in Figs. 1 and 2 but differs therefrom in virtue of the following features.

[0096] The light emitting device 103 comprises a first lens element 30 and a second lens element 31. The first lens element 30 forms a part of the top part 13 of the housing 4. The second lens element 31 forms a part of the body part 12 of the housing 4. More specifically the second lens element 31 forms an extension of the body part 12 of the housing 4 extending towards the top part 13 and enclosing the plurality of LEDs 2. The first lens element 30 may be a rigid lens or semi rigid lens. The second lens element 31 may be a rigid lens or a semi rigid lens. The first lens element 30 and the second lens element 31 are attached to the remaining parts of the housing 4.

[0097] The first lens element 30 and the second lens element 31 may extend along a part of or all of the longitudinal extension of the housing 4. The first lens element 30 and the second lens element 31 may, respectively, be one continuous lens as seen in the length direction, X. Alternatively, the first lens element 30 and the second lens element 31 may, respectively, comprise a series or plurality of lenses, such as one lens for each LED 2 of the plurality of LEDs 2, arranged after one another as seen in the length direction, X.

[0098] The protrusion 11 is provided on one of the first lens element 30 and the second lens element 31. The recess 10 is provided in the other one of the second lens element 31 and the first lens element 30. As shown on Fig. 10, the protrusion 11 is provided on the first lens element 30 and the recess 10 is provided in the second lens element 31. As further shown on Fig. 10, two recesses 10 and two protrusions are provided and are arranged on or at mutually opposite sides of the respective lens element 30 and 31 as seen in the width direction Z. Thereby, the recess 10 and the protrusion 11 are arranged such as to interfere minimally with the light emitted by the plurality of LEDs 2.

[0099] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0100] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

CLAIMS:

1. A light emitting device (1; 101; 102; 103) comprising: a plurality of LEDs (2) adapted for, in operation, emitting light in a main direction of emission (E), an elongated substrate (3), the plurality of LEDs being arranged along a longitudinal axis (L) of the elongated substrate, and a translucent, elastically deformable housing (4) enclosing the plurality of LEDs and the elongated substrate at least partially and comprising a length direction (X) extending in parallel with the longitudinal axis (L), a height direction (Y) extending in parallel with the main direction of emission (E) and a width direction (Z) extending perpendicular to both the length direction (X) and the height direction (Y), wherein the housing (4) further comprises: an elongated cavity (5) arranged downstream of the plurality of LEDs as seen in the main direction of emission (E) and extending in parallel with the length direction (X), the elongated cavity comprising a first surface part (6), a second surface part (7), a third surface part (8) and a fourth surface part (9), where the first surface part and the second surface part are mutually opposite surface parts as seen in the height direction (Y), and where the third surface part and the fourth surface part connect the first surface part and the second surface part, a recess (10) provided in one of the first surface part (6) and the second surface part (7), and a protrusion (11) provided on the other one of the first surface part (6) and the second surface part (7), and wherein the recess and the protrusion are configured for mutual, releasable engagement by elastic deformation of at least a part of the housing.

2. A light emitting device according to claim 1, wherein the recess (10) and the protrusion (11) are configured for being movable between a released position and an engaged position by elastic deformation of at least a part of the housing (4).

3. A light emitting device according to claim 1 or 2, wherein the cavity, the recess (10) and the protrusion (11) are constructed such that the light emitted by the plurality of LEDs propagates through the cavity in the released position of the recess and the protrusion, and such that at least a part of the light emitted by the plurality of LEDs does not propagate through the cavity in the engaged position of the recess and the protrusion.

4. A light emitting device according to any one of the above claims 2 and 3, wherein the protrusion (11) is configured to, in the released position, be arranged with a free end (27) located at a mouth (28) of the recess (10) or at a level of the one of the first surface part and the second surface part in which the recess is provided.

5. A light emitting device according to any one of the above claims, wherein the recess (10) is provided centrally in one of the first surface part and the second surface part as seen in the width direction (Z), and wherein the protrusion (10) is provided centrally on the other one of the first surface part and the second surface part as seen in the width direction (Z).

6. A light emitting device according to any one of the above claims, wherein the elongated cavity (5) is continuous in the length direction (X), and wherein the recess (10) and the protrusion (11) are continuous in the length direction (X).

7. A light emitting device according to any one of the above claims, wherein the size of the recess (10) as measured in the height direction (Y) is within 2 mm of the size of the cavity (5) as measured in the height direction (Y), or wherein the size of the recess (10) as measured in the height direction (Y) equals the size of the cavity (5) as measured in the height direction (Y), and / or wherein the size of the recess (10) as measured in the width direction (Z) is equal to or larger than the size of the LEDs of the plurality of LEDs (2) as measured in the width direction, (Z).

8. A light emitting device according to any one of the above claims, wherein the recess (10) and the protrusion (11) are configured for snap-locking or friction-locking mutual, releasable engagement.

9. A light emitting device according to any one of the above claims, wherein the housing (4) comprises a body part (12) enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part (6) of the cavity, a top part (13) comprising the second surface part (7) of the cavity and two side parts (14, 15) connecting the body part and the top part, wherein the recess (10) and the protrusion (11) are configured to be brought into mutual engagement by pressing a section (29) of the top part (13) towards the body part (12) in a direction (A) parallel with the height direction (Y).

10. A light emitting device according to claim 8, wherein the section (29) of the top part is a section of the top part being in direct connection with the recess (10) or the protrusion (11), or wherein the section (29) the top part is a central section of the top part (13) as seen in the width direction (Z).

11. A light emitting device according to any one of the above claims, wherein the housing (4) comprises a body part (12) enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part (6) of the cavity, a top part (13) comprising the second surface part (7) of the cavity and two side parts (14, 15), wherein the recess (10) and the protrusion (11) are configured to be released from mutual engagement by one or more of: pressing the two side parts (14, 15) towards each other in a direction (B or C) perpendicular to the height direction (Y), and pressing the two side parts (14, 15) away from each other by pressing on the top part (13) in a direction (D) forming an angle (6) of more than 45 degrees and less than 90 degrees with the height direction (Y).

12. A light emitting device according to any one of the above claims, wherein the housing (4) comprises a body part (12) enclosing the plurality of LEDs and the elongated substrate and comprising the first surface part (6) of the cavity, a top part (13) comprising the second surface part (7) of the cavity and two side parts (14, 15), wherein the light emitting device (103) further comprises a first lens element (30) and a second lens element (31), wherein the first lens element forms a part of the top part (13) ofthe housing (4), and wherein the second lens element forms a part of the body part (12) of the housing.

13. A light emitting device according to any one of the above claims, wherein the recess (10) comprises at least one engagement structure (16) and wherein the protrusion (11) comprises a complementary engagement structure (17), the complementary engagement structure being complementary to the at least one engagement structure.

14. A light emitting device according to claim 13, wherein the at least one engagement structure (16) is any one of an incision and a projection, and wherein the complementary engagement structure (17) is any one of a projection and an incision.

15. A light emitting device according to any one of claims 13 to 14, wherein the at least one engagement structure (16) is a continuous structure, and wherein the complementary engagement structure (17) is a continuous structure, or wherein the at least one engagement structure (16) is a discontinuous structure, and wherein the complementary engagement structure (17) is a discontinuous structure.

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