Sparkle spot light

Abstract

The invention provides a lighting system (1000) comprising (i) a plurality of light sources (10) configured to generate light source light (11), and (ii) optics (20) configured downstream of the light sources (10), wherein the lighting system (1000) further comprises a 2D array (110) of at least part of the total number of light sources (10), wherein nearest neighboring light sources (10) in the 2D array (110) have an average first shortest distance (dd1), wherein the lighting system (1000) is further configured to generate in an operation mode lighting system light (1001) comprising light source light (11) of a subset of the total number of light sources (10) wherein nearest neighboring light sources (10) configured to generate the light source light (11) for the lighting system light (1001) in the operation mode have an average second shortest distance (dd2), wherein the average second shortest distance (dd2) is larger than average first shortest distance (dd1).

Claims

1. A lighting system comprising (i) a plurality of light sources configured to generate light source light, and (ii) optics configured downstream of the light sources, wherein the lighting system further comprises a 2D array of at least part of the total number of light sources, wherein nearest neighboring light sources in the 2D array have an average first shortest distance, wherein the lighting system is further configured to generate in an operation mode lighting system light comprising light source light of a subset of the total number of light sources wherein nearest neighboring light sources configured to generate the light source light for the lighting system light in the operation mode have an average second shortest distance, wherein the average second shortest distance is larger than average first shortest distance, and wherein the lighting system comprises one or more additional light sources configured outside the 2D array at a third shortest distance of the additional light sources to the nearest neighbor in the array wherein said third shortest distance is at least 20% larger than the average second shortest distance, wherein two or more different subsets of the total number of light sources are configured to generate the lighting system light, wherein the lighting system is configured to generate in the operation mode the lighting system light while alternating over time between two or more of the two or more different subsets, and different subsets comprise identical light sources up to a maximum of 50% with the number of light sources in each subset being at least four.

2. The lighting system according to claim 1, wherein the optics comprises light transmissive optics selected from the group consisting of a lens and a collimator.

3. The lighting system according to claim 2, wherein the optics are configured to generate a beam of lighting system light having an opening angle (?) of equal to or less than 40?.

4. The lighting system according to claim 1, wherein the light sources comprise solid state light sources having first dimensions selected from the group of a first length, a first width, a first diagonal length, and a first diameter, and wherein the first dimension is selected from the range of 100 ?m-2 mm.

5. The lighting system according to claim 4, wherein the second average shortest distance is equal to or larger than the first dimension, wherein the first dimension is selected from a first length and a first width.

6. The lighting system according to claim 1, wherein the lighting system is configured to alternate between the two or more different subsets with a frequency of equal to or lower than 10 Hz.

7. The lighting system according to claim 6, wherein the lighting system is configured to alternate between the two or more different subsets while maintaining a fixed beam width of the lighting system light.

8. The lighting system according to claim 1, wherein two or more light sources of the total number of light sources are configured to provide light source light differing in one or more of the color point, color temperature, and color rendering index.

9. The lighting system according to claim 1, further comprising a control system, wherein the control system is configured to maintain a constant luminous flux of the lighting system light over time.

10. The lighting system according to claim 1, wherein the total number of light sources in the 2D array is equal to or larger than 36, wherein during the operation mode equal to or less than 35% of the total number of light sources is switched on.

11. The lighting system according to claim 1, wherein only the light sources comprises in the 2D array are optically coupled to the optics.

12. The lighting system according to claim 1, comprising a lighting device, wherein the lighting device comprises the plurality of light sources and the optics.

13. The lighting system according to claim 12, wherein the lighting device is a spot light.

14. Use of the lighting system according to claim 1 in a show room, a shop, a museum, or a hospitality area, for illuminating an object.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

(2) FIGS. 1a-1d schematically depict some aspects of embodiments of the lighting system (optics not depicted);

(3) FIGS. 2a-2b schematically depict some further aspects of embodiments of the lighting system;

(4) FIGS. 3a-3c schematically depict yet some further aspects of embodiments of the lighting system; and

(5) FIG. 4 schematically depict an embodiment of an application of the lighting system.

(6) The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) By making different combinations of sources and optics, several beam widths can be created. The housing determines roughly the maximum flux that can be generated. The maximum allowable input power of the LED source(s) may be determined by the amount of heat that can be transferred to the ambient. In general, a small source (COB with a small light emitting area or a closely packed array of Chip Scaled Packages, Mid Power Packages or MicroLEDs) may provide a relatively narrow beam with a high peak intensity, while a larger source (COB with a larger light emitting area or an array of CSPs with larger spacing) may result in a wider beam with lower peak intensity. However, comparable fluxes may be obtained. When the spacing between the CSPs is large, or when the color of the COB source is not uniform, the collimating optical element may provide a certain degree of mixing to make the beam uniform.

(8) FIG. 1a schematically depicts on the left a closely packed array of LEDs generating a narrow beam. FIG. 1a schematically shows in the middle also a closely packed array of LEDs, but generating a wider beam, dimmed to get the same flux. Further, FIG. 1a on the right schematically shows an array of LEDs with larger spacing generating a wider beam with the same flux. Note that when changing the subsets of light sources as indicated in FIG. 1a, the concomitant beam shape of the light generated by the light sources may also change.

(9) The hatched square surfaces within the circle on the left and in the circle on the right refer to light sources at e.g. maximum capacity. The hatched square surfaces within the circle in the middle drawing may refer to light sources that that are dimmed, such that the total flux is essentially the same as on the left. The white square areas refer to light sources which are switched off (or in specific embodiments at maximum 10% of its maximum power). Square areas outside the circle on the left or in the middle that are dashed, may be left out as light sources (in principle also applied to drawing on the right).

(10) The small areas (small squares) refer to light sources, indicated with reference 10. The small squares especially represent light emitting surfaces (or surfaces that emit light when the respective light source is switched on). The light sources have a first dimension d1, which is in this case the length or the width (which are equal in this schematically depicted embodiment of essentially square light sources 10/square light emitting areas). The light sources 10 have distances dd1 to neighboring light sources 10. The light sources 10 in this schematically depicted embodiment have a pitch (which is essentially dd1+d1). Further, the light sources 10 are essentially configured symmetrically around an optical axis O. The light sources 10 are configured in an array having cubic symmetry.

(11) The larger area of all small areas, i.e. the larger area of all light emitting surfaces may be indicated as light emitting area or lighting area. Reference 110 indicates an array. The array of light sources 10, or effectively the array of light emitting surfaces of the light sources 10, defines the array 110. There may also be light sources 10 external from the array (see also below). The array 110 essentially defines the lighting area (which comprises the light emitting surfaces or light emitting areas of the individual light sources).

(12) FIG. 1a also indicates the nearest neighbors of a randomly chosen light source. The latter light source is indicated with reference 10. This light source 10 has four nearest neighbors, which are indicated in the drawing with the thicker edge and with references 10nb. Would the light emitting surfaces of the light sources be configured in a Voronoi diagram (see also below), the four Voronoi cells would be the only Voronoi cells that share an edge with the Voronoi cell of the light source 10. Hence, nearest neighboring light sources 10 in the 2D array 110 have an average first shortest distance dd1. More precisely, in this example all light sources 10 have nearest neighboring light sources at distances dd1. Hence, the in the drawing indicated distances dd1 are thus also the average first shortest distance dd1.

(13) On the right of FIG. 1a, a subset of light sources of the array 110 are switched on; the remaining light sources are not switched on. The former may be indicated as active light sources, and similar terms.

(14) Note that instead of switching on and off, in other embodiments light sources may be dimmed up or dimmed down. Hence, a subset of light sources may primarily provide the lighting system light and one or more other light sources of the plurality of light source may also add to the lighting system light, but only with a relatively low power, such as equal to or less than 10% of the total power may be provided by light sources not within the subset that provides the lighting system light. A light source may be considered active when it is not dimmed down below about 10% of its maximum power.

(15) In the subset of light sources on the right of FIG. 1a, the distances between nearest neighbors that provide the lighting system light (i.e. the active light sources 10) are larger than between the light sources 10 of the array 110, which distance is dd1. Here, the distances between those light sources 10 that are switched on in the subset are at least the dimensions of the light sources, which is indicated with d1. The distances between these (active) light sources are indicated with dd2. Hence, these light sources 10 of the subset that provide the lighting system light during an operation mode have second shortest distance dd2. Here, these second shortest distance dd2 may differ, see also the drawing wherein the length of dd2 are different between different sets of the light source 10 and its active nearest neighbors. The second shortest distance dd2 for each light source of the light sources 10 of the subset may be averaged, leading to an average second shortest distance dd2.

(16) Hence, on the right in FIG. 1a schematically an embodiment of the lighting system 1000 comprising a plurality of light sources 10 configured to generate light source light is provided. The lighting system 1000 comprises a 2D array 110 of at least part of the total number of light sources 10, wherein nearest neighboring light sources 10 in the 2D array 110 have an average first shortest distance dd1. Further, the lighting system 1000 is configured to generate in an operation mode lighting system light 1001 comprising light source light of a subset of the total number of light sources 10 wherein nearest neighboring light sources 10 configured to generate the light source light for the lighting system light 1001 in the operation mode (i.e. the active light sources forming the subset) have an average second shortest distance dd2, wherein the average second shortest distance (dd2) is larger than average first shortest distance (dd1). Here, the average second shortest distance dd2 is at least d1.

(17) The luminance of a prior art spot is constant. The appearance can be glary or not glary, but it will not be perceived as sparkly. Sparkle (also known as beautiful glare or attractive glare) is especially based on spatial and/or temporal effects. Amongst others, it is herein proposed to add spatial (see amongst others FIG. 1a on the right) and/or temporal dynamics by switching on and off LEDs on specific positions, with little or no effect on the beam angle and the center beam intensity. The appearance of objects in the spot with diffuse reflective surfaces may essentially remain constant, but objects with specular reflective surfaces may show sparkle effects. Also, the spot itself will have a sparkling appearance when looking at it from a direction outside of the beam.

(18) In an embodiment of the invention a matrix array of LEDs (e.g. Chip Scaled Packages, Mid Power Packages or MicroLEDs) may be provided that extends over a specific area. Referring to FIG. 1b, at time t1, a fixed number of LEDs is switched on. They form a pattern within the specific area, making sure that the correct beam is produced. At a later point in time t2, another group of LEDs is switched on, with the same number but in a different pattern that still fills the specific area. At time t3, a third pattern with the same number of LEDs is chosen, etc. . . . The switching frequency is chosen to create a sparkle effect when looking at the optics from a fixed direction outside of the beam or at a specular reflecting object in the projected beam. This is schematically depicted in FIG. 1b. FIG. 1b schematically depicts an embodiment wherein at different moments in time, the same number of LEDs are switched on but in different patterns within the specific area.

(19) At relatively very low frequency the appearance will still be sparkly when the viewing direction changes in time.

(20) As schematically depicted with this 8*8 light sources array, it is possible to create a plurality (here 5 examples) of subsets with the same number of light sources that provide lighting system light. By alternating over time the subsets, a sparkle effect may be created. Hence, for the lighting system 1000 may apply that there may be two or more different subsets of the total number of light sources 10 that can be selected to generate the lighting system light. The lighting system 1000 may thus especially be configured to generate in the operation mode the lighting system light while alternating over time between two or more of the two or more different subsets. In embodiments, the lighting system 1000 may be configured to alternate between the two or more different subsets with a frequency of equal to or lower than 10 Hz. Hence, a control system (see also below), may be configured to have the lighting system generate lighting system light that is provided with (in time) alternating different subset of light sources, with a frequency (of alternation) of equal to or lower than 10 Hz.

(21) As also shown in FIG. 1b, there may be a low or essentially no impact on the beam shape of the lighting system light which is based on the light source light of the light sources 10 in the respective subsets (over time). Hence, the lighting system 1000 may be configured to alternate between the two or more different subsets while maintaining an essentially fixed beam width of the lighting system light 1001. Likewise, a constant luminous flux of the lighting system light over time may be maintained (while alternating the subsets during the operation mode).

(22) FIG. 1b thus also schematically depicts an embodiment a plurality of different subsets may be used over time to generate the lighting system light during the operation mode. The subsets differ in spatial arrangement of the light sources within the subset (during the operation mode). When there are two or more subsets, different subsets may e.g. have at maximum 50%, such as at maximum 35%, identical light sources.

(23) FIG. 1b also schematically depicts 11 an embodiment wherein the total number of light sources 10 in the 2D array 110 is equal to or larger than 36. Further, FIG. 1b also schematically depicts an embodiment wherein during the operation mode equal to or less than 35% of the total number of light sources 10 is switched on. Especially, during the operation mode equal to or less than 35% of the total number of light sources 10 may be active.

(24) FIG. 1c schematically depicts in a bit more detail a possible subset, but now in combination with a specific embodiment, wherein one or more light sources 10 are not configured in the array 110 but are configured external thereof. These light sources are indicated with reference 10. Hence, in embodiments, light sources, such as LEDs, may be configured outside of the specific area. Such light sources can e.g. be switched on and off in a chosen pattern and/or frequency. These light sources may have a very limited effect on the far field intensity distribution but can be used to enhance the sparkle effect when looking at the optics from a direction outside of the beam. The additional light sources may especially be placed sufficiently far away from the main source, such that their peak intensity is outside of the tail of the main beam. Here, the distance of the additional light sources to the nearest neighbor in the array 110 is indicated with dd3. Hence, FIG. 1c schematically depicts an embodiment of the lighting system 1000 comprising one or more light sources 10 configured at a third shortest distance dd3 to any nearest neighboring light source 10 from the light sources 10 of the 2D array 110. Especially, the third shortest distance (dd3) is at least five times the average first shortest distance (dd1). In embodiments, dd3?d1. In average (average over the total number of light sources 10 that are not configured within the array 110), dd3 may be equal to or larger than d1, such as equal to or larger than 1.1*d1.

(25) When in addition to light source 10 in the array 110 there are also light sources 10 outside the array, the average value of dd3 will in general be larger than the average value of dd2, like at least 10% larger, such as at least 20% larger, like at least 50% larger.

(26) Referring to amongst others FIGS. 1a, 1b and 1c, the light sources 10, such as solid state light sources, may have first dimensions d1 selected from the group of a first length, a first width, a first diagonal length, and a first diameter. In embodiments, the first dimension may be selected from the range of 100 ?m-2 mm. Further, in embodiments the second average shortest distance dd2 may be equal to or larger than the first dimension d1, wherein the first dimension d1 is selected from a first length and a first width, such as the first width.

(27) FIG. 1d schematically depict a non-regular array 110. Voronoi lines indicating equi-distances between neighboring light source 10 are indicated. Those cells that share an edge include neighboring light sources 10.

(28) Above embodiments were depicted and described without optical element. FIGS. 2a and 2b schematically depict some embodiments of the lighting system 1000 including the optical element. Here, embodiments of the lighting system 1000 comprising a plurality of light sources 10 configured to generate light source light 11, and optics 20 configured downstream of the light sources 10, are depicted. As indicated above, the lighting system 1000 comprises a 2D array 110 of at least part of the total number of light sources 10. The lighting system 1000 is further configured to generate lighting system light 1001 comprising light source light 11 of one or more of the light sources 10. In a specific operation mode, the lighting system light 1001 comprises light source light 11 of a subset of the total number of light sources 10. Reference O indicates an optical axis. Reference ? indicates the opening angle of the beam 1002 of lighting system light 1001.

(29) The optics 20 may especially comprise light transmissive optics selected from the group consisting of a lens 21 (see FIG. 2a) and a collimator 22 (see FIG. 2b). The lens may e.g. be a Fresnel lens. Especially, the optics 20 are configured to generate the beam 1002 of lighting system light 1001. As shown in FIG. 2b, the optics is mounted on a carrier 35 the additional light sources 10 mounted on the carrier 35 outside the 2D array 110 are not coupled with the optics 20, but only the light sources 10 located in the 2D array are optically coupled with the optics.

(30) In specific embodiments, wherein the optics 20 may be configured to generate a beam 1002 of lighting system light 1001 having an opening angle ? of equal to or less than 90?. For spot light applications, the opening angle may be smaller. Hence, in specific embodiments the optics 20 may be configured to generate a beam 1002 of lighting system light 1001 having an opening angle ? of equal to or less than 40?, such as equal to or less than 36?, like equal to or less than 25?.

(31) The light transmissive optics especially comprises a light transmissive material, especially a light transparent material. The light transmissive material may be transparent for one or more of UV radiation, visible light, and IR radiation, especially at least visible light. The light transmissive material may comprise one or more materials selected from the group consisting of a transmissive organic material, such as selected from the group consisting of PE (polyethylene), PP (polypropylene), PEN (polyethylene napthalate), PC (polycarbonate), polymethylacrylate (PMA), polymethylmethacrylate (PMMA) (Plexiglas or Perspex), cellulose acetate butyrate (CAB), silicone, polyvinylchloride (PVC), polyethylene terephthalate (PET), including in an embodiment (PETG) (glycol modified polyethylene terephthalate), PDMS (polydimethylsiloxane), and COC (cyclo olefin copolymer). Especially, the light transmissive material may comprise an aromatic polyester, or a copolymer thereof, such as e.g. polycarbonate (PC), poly (methyl)methacrylate (P(M)MA), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyethylene adipate (PEA), polyhydroxy alkanoate (PHA), polyhydroxy butyrate (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN); especially, the light transmissive material may comprise polyethylene terephthalate (PET). Hence, the light transmissive material is especially a polymeric light transmissive material. However, in another embodiment the light transmissive material may comprise an inorganic material. Especially, the inorganic light transmissive material may be selected from the group consisting of glasses, (fused) quartz, transmissive ceramic materials, and silicones. Also hybrid materials, comprising both inorganic and organic parts may be applied. Especially, the light transmissive material comprises one or more of PMMA, transparent PC, or glass.

(32) FIGS. 2a-2b also schematically depict an embodiment wherein the lighting system 1000 further comprises a control system 30. The control system 30 may in embodiments be configured to alternate the subset over time in the control mode. The control system 30 may also be configured to maintain a constant luminous flux of the lighting system light 1001 over time. The control system 30 may also be configured to control the lighting system light in other operation modes (or control modes). The control system 30 may be configured to control one or more of color point, color temperature, and color rendering index. The control system may also be configured to select a subset during the operation mode, thereby having the lighting system light being based on the light source light of the subset of light sources. When over time the subset is not changed to another subset, there may still be a sparkle effect (see also above, amongst others at FIG. 1a).

(33) FIGS. 2a-2b schematically also depict embodiments wherein the light sources 10 and optical element 20 are comprised by a single lighting device 100. Hence, these figures also schematically depict embodiments wherein the lighting system 1000 comprises a lighting device 100, wherein the lighting device 100 comprises the plurality of light sources 10 and the optics 20. For instance, in embodiments the lighting device 100 is a spot light. The lighting device is especially configured to generate lighting device light 101. Note that in embodiments the lighting device light 101 may essentially be the lighting system light 1001. Hence, all embodiments described herein in relation to the lighting system light 1001 may also apply to the lighting device light 101.

(34) Reference 25 refers to a reflector, such as with an aluminum layer or other specular reflective material. Reference 120 indicates a housing.

(35) In embodiments, the array 110 may comprise light sources, such as LEDs, configured to emit (mutually) different colors (i.e. different spectral power distributions), as schematically depicted in FIGS. 3a-3b. The individual hatchings may in embodiments add up to a certain white point at a specific point in time. This may in embodiments lead to colors at the edge of the beam, even if mixing structures are applied. In embodiments, in case clusters of RGB(W) LEDs are used (see FIG. 3b), in embodiments each cluster may vary in color over time (with the time-averaged color being a certain white and spatially averaged color being a certain white).

(36) In embodiments, colored light sources, such as LEDs, may be configured (far) outside the specific area, while the light sources, such as LED(s), within the specific area are white. In this way a colored sparkle outside of the beam is created, see e.g. FIG. 3c, but especially also FIG. 1c.

(37) Referring to FIGS. 3a-3c, in embodiments two or more light sources 10 of the total number of light sources 10 may be configured to provide light source light 11 differing in one or more of the color point, color temperature, and color rendering index.

(38) Very schematically, an application is shown in FIG. 4. Here, the lighting system 1000 comprises two lighting devices (such as luminaire), which each may generate the beam of lighting system light 1001/lighting device light 101, with the sparkle effect as described herein. For instance, the lighting system 1000 may be used in a show room, a shop, a museum, or a hospitality area, for illuminating an object.

(39) The term plurality refers to two or more.

(40) The terms substantially or essentially herein, and similar terms, will be understood by the person skilled in the art. The terms substantially or essentially may also include embodiments with entirely, completely, all, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term substantially or the term essentially may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

(41) The term comprise includes also embodiments wherein the term comprises means consists of.

(42) The term and/or especially relates to one or more of the items mentioned before and after and/or. For instance, a phrase item 1 and/or item 2 and similar phrases may relate to one or more of item 1 and item 2. The term comprising may in an embodiment refer to consisting of but may in another embodiment also refer to containing at least the defined species and optionally one or more other species.

(43) Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

(44) The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

(45) It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

(46) In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

(47) Use of the verb to comprise and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of including, but not limited to.

(48) The article a or an preceding an element does not exclude the presence of a plurality of such elements.

(49) The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. 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.

(50) The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

(51) The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

(52) The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.