Insert for a light emitting device

Abstract

The invention relates to a light emitting device (1) comprising: a substrate (2) comprising a plurality of individually controllable light sources (3) adapted to emit light in operation; and at least one insert (4) comprising a material at least partially blocking light and having a longitudinal extension parallel to the substrate (2). The insert (4) comprises a plurality of lateral elements (5) having a proximal end (5 ') arranged adjacent to the substrate (2) and a distal end (5' ') arranged at a distance from the proximal end (5'). The transverse elements (5) are substantially perpendicular to the substrate (2), the plurality of transverse elements (5) dividing the substrate into at least a first section (6 ') comprising the first group of light sources (3'), a second section (6 '') comprising the second group of light sources (3 ''), and a third section (6 ''') comprising the third group of light sources (3''').

Description

Technical Field

[0001] The invention relates to a lighting device comprising an insert and a luminaire comprising such a lighting device. Background Art

[0002] LED lighting tiles designed to fit in suspended ceilings are usually backlit using an array of LEDs on the rear of the panel. Alternatively, edge-lit panels use a light guide to distribute light from LEDs mounted on the sides of the panel. The arrangement of LEDs in a backlit panel, such as the Philips Ledinaire (600mm x 600mm) can be 6 rows, each row comprising 9 LEDs.

[0003] It is also known to provide a pattern tile with an insert that divides the tile into two individually controllable sections. These pattern tiles can be combined and operated in different configurations to obtain lighting patterns. In order to achieve this effect, it is important to have a good contrast between the illuminated and non-illuminated areas of the tile. This can be achieved by dividing the tile with light blocking elements and addressing the LEDs in each section individually.

[0004] However, there remains a need for improved inserts for use with LED panels, such that the variety of patterns obtainable by operating different sections of the LED panel can be increased.

[0005] US20080285280A1 discloses a lighting module, which includes: an LED array arranged on a carrier; a grid arranged at the carrier; and a front diffusion plate arranged in front of the grid. Summary of the invention

[0006] Therefore, it is an object of the present invention to provide a light emitting device comprising an insert to provide increased flexibility in the patterns obtainable by the light emitting device. To this end, the present invention provides a light emitting device comprising a substrate comprising a plurality of individually controllable light sources adapted to emit light in operation. The plurality of light sources may be arranged in straight parallel rows, circles, rectangles or any other desired pattern across the substrate. The light sources may be LED light sources. Arranging the light sources in parallel rows provides the advantage of a simplified insert configuration.

[0007] The light emitting device further comprises at least one insert comprising a material that at least partially blocks light, such as a translucent material.

[0008] The insert has a longitudinal extension parallel to the substrate. The longitudinal extension of the insert is preferably the same as or slightly shorter than the longitudinal extension of the substrate. The insert comprises a plurality of transverse elements having a proximal end (i.e., a proximal edge) and a distal end (i.e., a distal edge), the proximal end being arranged near the substrate, and the distal end being arranged at a distance from the proximal end. The distance between the proximal end and the distal end can be from 1 cm to 20 cm. These transverse elements are arranged substantially perpendicular to the substrate. The term "substantially perpendicular" refers to being arranged at 90 ° relative to the substrate or being arranged at an angle slightly deviating from 90 ° relative to the substrate. For example, the transverse elements can be arranged at an angle of 80 ° to 100 ° relative to the substrate. It is further conceivable that these transverse elements are arranged at different angles relative to the substrate. This embodiment provides the advantage of enhanced optical performance of the light emitting device.

[0009] The plurality of lateral elements divide the substrate into at least a first section, a second section and a third section, the first section comprising a first group of light sources, the second section comprising a second group of light sources, and the third section comprising a third group of light sources. Different groups of light sources can be individually operated to produce a desired pattern. The number of sections can be at least five, at least ten or at least fifteen. An increased number of sections provides an increased number of available patterns.

[0010] The plurality of transverse elements may be arranged in a straight configuration, a curved configuration, or a combination thereof. The transverse elements may be interdigitated.

[0011] The plurality of transverse elements may be integrally formed as a single piece, thus forming a single insert. Alternatively or additionally, the transverse elements may be formed as separate components. In such an embodiment, the transverse elements may be interconnected and / or arranged on a substrate in a specific pattern to form at least one insert at a subsequent stage of the manufacturing / assembly steps of the light emitting device.

[0012] Each of the plurality of transverse elements has a length Ld, a thickness T, and a height H from the proximal end to the distal end in a longitudinal direction substantially parallel to the plane of the substrate. The thickness T and the height H are measured perpendicular to the light direction. The height H of the transverse element is measured substantially perpendicular to the plane of the substrate (e.g., 90°±10° to the substrate). The length, height and / or thickness of each transverse element may be the same or different from the length, height and / or thickness of other transverse elements.

[0013] The distal end of each transverse element may have a straight or smoothly curved shaped profile which is different from the shaped profile of the proximal end of each transverse element which may be straight, stepped upright or stepped curved. The stepped upright or stepped curved configuration provides the advantage of avoiding the transverse element from intersecting the light generating / emitting portion of any of the plurality of light sources, while the light sources may still be advantageously arranged, for example, in a convenient square grid. In embodiments where, for example, the proximal end has a stepped profile and the distal end is smoothly curved, the transverse element gradually deforms / changes shape over its height from the stepped profile to a different (e.g. smooth) profile when viewed in a projection onto a plane along the height of the transverse element.

[0014] The light emitting device may comprise a light exit window, which is arranged substantially parallel to the substrate, so that the distal end of the at least one transverse element is arranged close to or in contact with the light exit window, thereby canceling crosstalk (light leakage) between adjacent segments. If the distal end of the transverse element is arranged near the light exit window, the distance between the distal end of the transverse element and the light exit window should preferably not exceed the thickness of the distal end of the transverse element.

[0015] The light exit window may be a diffuse transmission sheet. Alternatively or additionally, the light exit window may be a light collimating plate. Depending on the beam profile for a particular desired function of the light emitting device, such an embodiment provides the advantage of improved matching optical performance.

[0016] The distal end of the transverse element may have a thickness below 0.2 mm. Such an embodiment provides the advantage of providing a barely visible insert, in particular when the lighting device further comprises a light exit window panel arranged adjacent to or in contact with the distal end of the transverse element. It should be noted that the thickness of the transverse elements may be non-uniform. In particular, the transverse elements may have a thickness that decreases from the proximal end to the distal end.

[0017] The insert may comprise a frame, and the transverse elements may be arranged within the frame. The frame may have any suitable shape and size, for example, rectangular, square, oval, circular, etc. The frame may facilitate manufacture, transport and installation of the insert.

[0018] In order to reduce absorption of light and ensure that the insert is not visible through the light exit window panel, at least one of the plurality of transverse elements may comprise a reflective coating. Preferably, all transverse elements comprise a reflective coating. Such an embodiment has the advantage of providing improved optical performance of the light emitting device.

[0019] Depending on the configuration of the light sources and the transverse elements of the frame, at least one light source may be covered by the transverse element, which impairs the contrast between the sections of the light emitting device, resulting in a poor optical pattern. In order to avoid this undesirable consequence, the proximal end of at least one transverse element may be non-straight. In such an embodiment, the proximal end of the at least one transverse element will not intersect with any of the plurality of light sources. In the context of the present invention, the term "non-straight" may refer to a stepped or zigzag configuration.

[0020] In order to maximize the optical efficiency, at least the distal end of at least one transverse element may be white. Furthermore, it may be important to ensure that light emitted by the light source is not transferred from the light emitting section to the non-light emitting section. Then, the transverse element should completely block the light by absorption and / or reflection, for example because the translucent material of the transverse element is coated with a reflective, opaque coating.

[0021] The insert of the present invention may be manufactured by 3D printing, for example by fused deposition modeling (FDM). Alternatively, the insert may be manufactured by injection molding.

[0022] The present invention also relates to a luminaire comprising a light emitting device according to the above. The luminaire may further comprise a fixing element configured to support the light emitting device. The fixing element may be a wire, a screw, a hook, etc. In a particular embodiment, the luminaire is configured for suspension. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiments of the invention.

[0024] Figure 1 shows a perspective view of a lighting device comprising an insert according to the invention;

[0025] Figure 2 A cross-sectional view of a light emitting device according to the present invention is shown;

[0026] 3A-3C show different patterns that can be obtained in a light emitting device according to the present invention;

[0027] 4A and 4B illustrate an embodiment of an insert of the present invention that provides an improved pattern edge;

[0028] 5A-6B illustrate different embodiments of inserts similar to the insert shown in FIGS. 4A-4B .

[0029] As shown in the figures, the sizes of layers and regions are exaggerated for illustrative purposes, and thus, the layers and regions are provided to illustrate the general structure of embodiments of the present invention. Like reference numerals refer to like elements throughout. DETAILED DESCRIPTION

[0030] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the present invention are shown. However, the present invention may be embodied in many different forms and the present invention should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the present invention to the skilled person.

[0031] Figure 1 There is shown a light emitting device 1 comprising a substrate 2 comprising a plurality of individually controllable light sources 3 adapted to emit light in operation. The plurality of light sources 3 are arranged in a row.

[0032] The lighting device 1 further comprises an insert 4 comprising a material that at least partially blocks light, for example a translucent material.

[0033] The insert 4 has a longitudinal extension R parallel to the substrate 2. The longitudinal extension R of the insert is identical to the longitudinal extension of the substrate 2. The insert 4 comprises a plurality of transverse elements 5 having a proximal end 5' arranged near the substrate 2 and a distal end 5". The distance between the proximal end 5" and the distal end 5" may be from 1 cm to 20 cm. The transverse elements 5 are arranged substantially perpendicular to the substrate 2. It is further conceivable that the transverse elements 5 are arranged at different angles relative to the substrate 2. Such an embodiment provides the advantage of an enhanced optical performance of the light emitting device 1.

[0034] Each of the plurality of transverse elements has a length Ld, a thickness T, and a height H from the proximal end to the distal end in a longitudinal direction substantially parallel to the plane of the substrate. The thickness T and the height H are measured perpendicular to the light direction. The height H of the transverse element is measured substantially perpendicular to the plane of the substrate (e.g., 90°±10° to the substrate). The length, height and / or thickness of each transverse element may be the same or different from the length, height and / or thickness of other transverse elements.

[0035] A plurality of transverse elements 5 divide the substrate 2 into at least a first section 6' comprising a first group of light sources 3', a second section 6", and a third section 6'"', the first section 6' comprising a first group of light sources 3', the second section 6", comprising a second group of light sources 3", and the third section 6'"' comprising a third group of light sources 3'". Different groups of light sources 3', 3", and 3" can be operated individually to produce a desired pattern. The number of sections can be at least five, at least ten, or at least fifteen. An increased number of sections provides an increased number of available patterns. Different patterns that can be provided by the insert are depicted in Figures 3A-3C.

[0036] The plurality of transverse elements 5 are arranged in a combination of straight and curved configurations. In particular, the insert 4 comprises eight curved transverse elements and four straight elements. The transverse elements 5 are crossed.

[0037] The light emitting device 1 comprises a light exit window 8 which is arranged substantially parallel to the substrate 2 such that a distal end 5 ″ of the at least one transverse element 5 is arranged in contact with the light exit window 8 .

[0038] The light exit window 8 may be a diffuse transmission sheet. Alternatively or additionally, the light exit window 8 may be a light collimating plate.

[0039] The insert 4 may comprise a frame 7, and the transverse elements 5 may be arranged within the frame 7. In the figures shown, the frame 7 is square, but as mentioned above, it may have any suitable shape.

[0040] If available Figure 2 As can be seen in FIG. 1 , light sources 3 ′, 3 ″ and 3 ″ are individually controllable. Figure 2 In the embodiment shown in FIG. 5 , the first group of light sources 3 ′ in the first section 6 ′ is turned off, while the second and third groups of light sources 3 ″ and 3 ′″ are turned on.

[0041] Figure 4a A light emitting device 101 comprising a substrate 102 is shown. As described above, depending on the configuration of the transverse elements 105 and the light sources 103 of the insert 104, at least one light source may be covered by the transverse element, which weakens the contrast between the sections of the light emitting device, resulting in a poor optical pattern. In order to avoid this undesirable effect, the proximal end 105' of at least one transverse element 105 may be non-straight, as shown in Figures 4A and 4B. In such an embodiment, the proximal end 105' of at least one transverse element 105 will not intersect any of the plurality of light sources 103. In the context of the present invention, the term "non-straight" may refer to a stepped or zigzag configuration.

[0042] As described above, the distal end 105", 205", and 305" of each transverse element 105, 205, 305 may be straight or smoothly curved. The proximal end 105', 205', and 305' of each transverse element 105, 205, 305 may be straight, stepped upright, or stepped curved. As described above, the stepped upright configuration or the stepped curved configuration provides the advantage of avoiding the transverse element from intersecting the light generating / emitting portion of any of the plurality of light sources 106, such as Figure 4a As shown in Figure 4a , Figure 5a and Figure 6aIt can be seen that the transverse element gradually deforms / changes shape over its height from a stepped profile to a smooth profile when viewed in a projection onto a plane along the height of the transverse element, the proximal end having a stepped profile and the distal end being smoothly curved.

[0043] FIG. 5A shows an embodiment of a light emitting device 201 comprising a substrate 202 and an insert 204, wherein the proximal end 205' of the insert 205 has a corrugated configuration, thereby providing a sharp contraction as can be seen in FIG. 5B. Such an insert can be used if the light emitting device comprises many small light sources. Another embodiment is shown in FIG. 6A, wherein the proximal end 305' of the insert 305 has only two non-straight portions. As can be seen in FIG. 6B, even in this case, the contrast between the illuminated section and the non-illuminated section is good.

[0044] Those skilled in the art will recognize that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, if the emitted light is highly directional, no beam shaping element will be required to meet the requirements of the present invention.

[0045] Moreover, variations to the disclosed embodiments will be understood and effected by those skilled in the art in practicing the claimed invention, by studying 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 measures cannot be used to advantage.

Claims

1. A light emitting device (1), comprising: a substrate (2) comprising a plurality of individually controllable light sources (3), the light sources (3) being adapted to emit light in operation, at least one insert (4) comprising a material that at least partially blocks light and having a longitudinal extension parallel to the substrate (2), the insert (4) comprising a plurality of transverse elements (5), the transverse elements having a proximal end (5') arranged adjacent to the substrate (2) and a distal end (5") arranged at a distance from the proximal end (5'), the transverse elements (5) being substantially perpendicular to the substrate (2), the plurality of transverse elements (5) dividing the substrate into at least a first section (6'), a second section (6") and a third section (6'"), the first section comprising a first group of the light sources (3'), the second section (6") comprising a second group of the light sources (3"), the third section (6'") comprising a third group of the light sources (3'"), wherein the proximal end (5') of the at least one transverse element (5) does not intersect any light source of the plurality of light sources (3), and Wherein said transverse element gradually deforms or changes shape over its height to become a different profile at said distal end (5").

2. The lighting device (1) according to claim 1, wherein the distal end (5") of the transverse element (5) has a thickness lower than 0.2 mm.

3. The lighting device (1) according to claim 1 or 2, wherein each of the transverse elements (5) is crossed.

4. The lighting device (1) according to any of the preceding claims, wherein the insert (4) comprises a frame (7), and wherein the transverse element (5) is arranged within the frame (7).

5. The lighting device (1) according to any of the preceding claims, wherein at least one transverse element (5) of the plurality of transverse elements (5) comprises a reflective coating.

6. A light emitting device (1) according to any one of the preceding claims, wherein the plurality of light sources (3) are arranged in the form of parallel rows across the substrate (2).

7. Lighting device (1) according to any of the preceding claims, wherein the proximal end (5') of the at least one transverse element (5) is non-straight.

8. A light-emitting device (1) according to any one of the preceding claims, wherein the light-emitting device (1) further comprises a light exit window (8), which is arranged substantially parallel to the substrate (2), so that the distal end (5") of the at least one transverse element (5) is arranged adjacent to the light exit window (8) or in contact with the light exit window.

9. The lighting device (1) according to claim 8, wherein the light exit window (7) is a diffuse transmission sheet.

10. The lighting device according to claim 8 or 9, wherein the light exit window (7) is a light collimating plate.

11. Lighting device (1) according to any one of claims 8 to 10, wherein at least the distal end (5") of the transverse element (5) is white.

12. The lighting device (1) according to any one of the preceding claims, wherein the proximal end has a stepped profile and the distal end is smoothly curved, and wherein the transverse element gradually deforms or changes shape over its height from the stepped profile to the smooth profile.

13. The lighting device (1) according to any one of the preceding claims, wherein the insert (4) is manufactured by fused deposition modeling (FDM).

14. A luminaire comprising a light emitting device (1) according to any one of the preceding claims and a fixing element, the fixing element being configured to support the light emitting device.

15. The luminaire of claim 14, wherein the luminaire is configured for a suspended configuration.

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