Patent Grant
11933487
This application is the U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2020/086300, filed on Dec. 15, 2020, which claims the benefit of European Patent Application No. 20150036.0, filed on Jan. 2, 2020. These applications are hereby incorporated by reference herein.
The present invention generally relates to lighting devices, e.g. comprising one or more light emitting diodes (LEDs). More specifically, the lighting devices are arranged to provide a decorative lighting while at the same time being able to provide a dynamic shadowing and to reduce glare during operation.
The use of light emitting diodes (LEDs) for illumination purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, a reduced power consumption, and an increased efficiency related to the ratio between light energy and heat energy.
It is of interest to have lighting devices and/or arrangements (such as lamps) which are able to produce decorative (white) light and induce improved and/or new dynamic shadows while being able to reduce glare. In the prior art, there are numerous examples of lighting devices which are intended to produce decorative light. However, these lighting devices are often unable to provide a dynamic shadowing of the light emitted therefrom. Furthermore, the lighting devices are often unable to reduce glare in a satisfactory manner.
Hence, it is an object of the present invention to provide alternatives to existing lamps of the prior art in order to obtain a more decorative lighting while at the same time providing a dynamic shadowing and reducing glare.
Hence, it is of interest to overcome at least some of the deficiencies of the present lamps of the prior art in order to provide a lighting device which may achieve a decorative lighting while at the same time being able to provide a dynamic shadowing of the light emitted therefrom and to reduce glare of during operation.
This and other objects are achieved by providing a lighting device having the features in the independent claim. Preferred embodiments are defined in the dependent claims.
Hence, according to the present invention, there is provided a lighting device comprising a plurality of light sources. The lighting device further comprises a cover comprising an at least partially light-transmissive material, wherein the cover at least partially encloses the plurality of light sources. The lighting device further comprises a plurality of reflectors arranged within the cover and at respective peripheral portions of the cover. A first set of light sources is arranged within the plurality of reflectors such that the light sources within each reflector is configured to emit a respective bundle of light from the lighting device. A second set of light sources is arranged outside the plurality of reflectors and is configured to emit light from the lighting device. The lighting device further comprises a control unit configured to individually control the operation of the first and second sets of light sources.
Thus, the present invention is based on the idea of a lighting device comprising at least two sets of light sources being individually controllable. The first set of light sources is arranged within the plurality of reflectors such that the light emitted from the first set of light sources during operation of the lighting device is directed towards a (discrete) portion of the exit surface of the cover of the lighting device. The second set of light sources is arranged outside the plurality of reflectors such that the light emitted from the second set of light sources during operation of the lighting device exits the lighting device by the mixing chamber as defined by the cover of the lighting device. By this configuration, the lighting device may hereby provide a dynamic shadow effect of the light emitted from the lighting device, wherein the sharpness of the shadows may be controlled by the control unit. By controlling (adjusting) the intensity of the first and second sets of light sources via the control unit, the lighting device of the present invention may provide a decorative lighting while at the same time providing a dynamic shadowing and a reduced glare.
The present invention is hereby advantageous in that the lighting device may obtain an aesthetically appealing lighting effect, while glare may be at least partially reduced, or even eliminated, by the innovative concept of the lighting device.
It will be appreciated that the lighting device of the present invention furthermore comprises relatively few components. The relatively low number of components is advantageous in that the lighting device is relatively inexpensive to fabricate. Moreover, the relatively low number of components of the lighting device implies an easier recycling, especially compared to devices or arrangements comprising a relatively high number of components which impede an easy disassembling and/or recycling operation.
The lighting device comprises a plurality of light sources. The plurality of light sources is preferably light emitting diodes, LEDs. The lighting device further comprises a cover comprising an at least partially light-transmissive material, wherein the cover at least partially encloses the plurality of light sources. By the term “cover”, it is here meant an enclosing element, such as a cap, cover, envelope, or the like, comprising an at least partial light-transmissive material, e.g. a translucent and/or transparent material.
The cover defines a mixing chamber for at least a portion of the light emitted from the plurality of light sources during operation. By the term “mixing chamber”, it is here meant a space wherein light may be reflected before exiting the mixing chamber.
The lighting device further comprises a plurality of reflectors arranged within the cover and at respective peripheral portions of the cover. A first set of light sources is arranged within the plurality of reflectors such that the light sources within each reflector is configured to emit a respective bundle of light from the lighting device. A second set of light sources is arranged outside the plurality of reflectors and is configured to emit light from the lighting device. Hence, the light emitted from the second set of light sources is mixed in the mixing chamber defined by the cover of the lighting device, whereas the light emitted from the first set of light sources is emitted, at least partially via the plurality of reflectors, as bundles of light.
The lighting device further comprises a control unit configured to individually control the operation of the first and second sets of light sources. By “control unit”, it is here meant substantially any unit, device, arrangement, or the like, which is coupled or connected to the first and second sets of light sources in order to control the first and second sets of light sources, respectively. By the term “control the first and second sets of light sources”, it may here be meant that the control unit is configured to control the intensity of the light emitted from the first and second sets of light sources.
According to an embodiment of the present invention, the control unit may be configured to vary the luminous flux of the light emitted from at least one of the first and second set of light sources. It will be appreciated that the ratio between the luminous flux of the light emitted from the first set of light sources and second set of light sources may change as function of time. The present embodiment is advantageous in that an even more decorative lighting and dynamic shadowing of the light emitted from the plurality of light sources may be obtained.
According to an embodiment of the present invention, the control unit may be configured to maintain the total luminous flux of the light emitted from the first and second set of light sources constant as a function of time. In other words, the control unit may be configured to maintain or keep the total luminous flux of the light emitted from the first and second set of light sources within a (relatively small) predetermined interval as a function of time. For example, the control unit may be configured to vary the luminous flux of the light emitted from the first and second set of light sources individually, albeit the total luminous flux is held constant as a function of time.
According to an embodiment of the present invention, the cover may comprise a plurality of first portions respectively arranged in front of each reflector of the plurality of reflectors, and a second portion of the cover separate from the plurality of first portions, wherein at least one property of the plurality of first portions comprises is different from at least one property of the second portion. In other words, the plurality of first portions may comprise at least one property (e.g. a physical, mechanical and/or optical property) which is different from at least one property (e.g. a physical, mechanical and/or optical property) of the second portion. For example, and according to an embodiment, a surface area of the plurality of first portions may be at least two times smaller than a surface area of the second portion, the plurality of first portions may have a lower reflectance than the second portion, and/or a maximum intensity at the first portions may be at least twice as high as a maximum intensity at the second portion of the light emitted from the plurality of light sources during operation. The obtained effect of this embodiment is an improved decorative lighting while at the same time providing a dynamic shadowing and reducing glare. The plurality of first portions may have the same shape, whereby the obtained effect encompasses improved shadows during operation of the lighting device. The reason is that the lighting device may provide the same type of shadows in each direction of the lighting device, e.g. in case a homogeneous mask/shadowing means is applied. Furthermore, the plurality of first portions may have different shapes, e.g. a shape selected from the group consisting of a circle, an oval, a square, and a polygon shape (e.g. a pentagon shape, a hexagon shape, or a heptagon shape). Moreover, the plurality of first portions may have a shape having a longest diameter and a shortest diameter, wherein the ratio between the longest diameter and the shortest diameter is in the range of 0.8-1.2. The obtained effect of this embodiment is an improved shadowing effect, as these shapes have a substantially constant diameter in all directions.
According to an embodiment of the present invention, the first set of light sources may be configured to provide light having a first color temperature, CT1, and the second set of light sources may be configured to provide light having a second color temperature, CT2. The difference in color temperature between the first and second color temperatures may be at least 300 K, more preferably at least 500 K, and most preferred at least 700 K. By this features, different color temperatures can be generated, e.g. in that the lighting device may provide shadows and/or a background illumination. Hence, the present embodiment is advantageous in that an improved decorative lighting may be obtained. Furthermore, the difference in color temperature between the first and second color temperatures may be less than 1200 K, more preferably less than 1100 K, and most preferred less than 1000 K. The present embodiment is advantageous in that a relatively small difference in color temperatures results in an aesthetically desirable light, which in turn results in an improved decorative lighting.
According to an embodiment of the present invention, the first color temperature and the second color temperature may be the same. The present embodiment is advantageous in that the light emitted from the lighting device during operation may have a uniform color temperature, resulting in a homogeneous lighting.
Furthermore, the first color temperature and the second color temperature may be in the range of 1800-5000 K, more preferably in a range of 1900-4000 K, and even more preferred in a range of 2000-3500 K. The first color temperature and the second color temperature may have a color rendering index of at least 80.
According to an embodiment of the present invention, the plurality of reflectors and the first set of light sources may be arranged within the lighting device such that the bundles of light emitted from the lighting device during operation have an overlap which is less than 30%, preferably less than 25%, and even more preferred less than 20%. The present embodiment is advantageous in that the overlap of the light emitted from the first set of light sources is relatively small, thereby enhancing the shadow quality.
According to an embodiment of the present invention, the plurality of reflectors and the first set of light sources may be arranged within the lighting device such that the bundles of light emitted from the lighting device during operation have an overlap which is more than 1%, preferably more than 3%, and even more preferred more than 5%. The present embodiment is advantageous in that a minimum overlap of 1%, preferably 3%, and even more preferred 5%, may create even more homogenous color shadows of the light emitted from the lighting device.
According to an embodiment of the present invention, the reflectors of the plurality of reflectors may be arranged equidistantly along the periphery of the cover. The present embodiment is advantageous in that the symmetric arrangement of the plurality of reflectors of the lighting device contributes to the aesthetic appearance of the lighting device as such. Furthermore, the symmetric arrangement of the plurality of reflectors contributes to a symmetric emission of light from the lighting device, which further enhances the decorative aspect of the emitted light.
According to an embodiment of the present invention, the reflectors of the plurality of reflectors may be arranged along the periphery of the cover and may be separated by an angle of at least 20°, more preferably at least 25°, and even more preferred at least 30°.
According to an embodiment of the present invention, the number of reflectors may be in the range of 2-5, more preferably 3 or 4, and even more preferred 3.
According to an embodiment of the present invention, the cover may comprise a plurality of apertures, and wherein each aperture is arranged to let through a respective bundle of light from the lighting device. The present embodiment is advantageous in that the lighting device may produce shadows, wherein the sharpness of the shadows may be controlled by the control unit, controlling the light intensity from the first and second sets of light sources, respectively. In case the control unit controls the light intensity of the first and second sets of light sources such that the intensity of the light emitted from the first set of light sources is set at a relatively high level, or even at a maximum level, and the intensity of the light from the second set of light sources is set at a relatively low level, at a minimum level, or in an off state, the lighting device is able to provide sharp shadows. The present embodiment is further advantageous in that the control unit may be configured to adjust the intensity of the light emitted from the first and second set of light sources such that the shadow contrast is adjusted.
According to an embodiment of the present invention, the plurality of apertures may be arranged equidistantly in a circumferential direction of the cover, and wherein the length between pair of apertures is at least 5 mm, more preferably at least 8 mm, and even more preferred at least 10 mm. The present embodiment is advantageous in that the symmetric arrangement of the plurality of apertures of the lighting device contributes to the aesthetic appearance of the lighting device as such, as well as the light emitted therefrom. The present embodiment is further advantageous in that the (color) shadow effect of the light from the lighting device during operation may be improved even further.
According to an embodiment of the present invention, at least one reflector of the plurality of reflectors may be at least partially reflective.
According to an embodiment of the present invention, at least one reflector of the plurality of reflectors may comprise an at least partially reflective layer.
According to an embodiment of the present invention, at least one reflector may have a reflectance of >80%, more preferably >85%, and even more preferred >90%. The present embodiment is advantageous in that the reflectance as exemplified provides light beams with improved shadowing properties and an improved decorative lighting of the lighting device, as a major part of the light emitted from the lighting device during operation is emitted from the first set of light sources and via the reflectors. It will be appreciated that there may also be a difference between the reflectance of the at least one reflector with respect to a reflectance of the cover. For example, the difference may be at least 30%. It will be appreciated that a relatively low reflectance of the reflector(s) provides improved bundles of light from the first set of light sources with respect to the shadowing effect of the emitted light.
According to an embodiment of the present invention, the cover may have a reflectance in the range of 20-70%, more preferably 25-60%, and even more preferred 30-50%. For example, the cover may constitute a semi-reflective light exit window. The obtained effect of this embodiment is a homogeneous lighting and efficiency of the lighting device. It will be appreciated that a relatively high reflectance of the cover leads to a relatively high mixing of the light in the mixing chamber of the lighting device.
According to an embodiment of the present invention, the cover may be bulb-shaped and may elongate along an axis, A, and wherein at least two reflectors of the plurality of reflectors are arranged in a plane, B, perpendicular to the axis, A.
According to an embodiment of the present invention, the cover may have an absorption less than 7%, more preferably less than 5%, most preferred less than 3%, such as 1% or even <1% during operation of the lighting device. The present embodiment is advantageous in that there is a relatively high efficiency of the mixing in the mixing chamber of the lighting device.
According to an embodiment of the present invention, the cover may be bulb-shaped and may elongate along an axis, A, and wherein at least one reflector of the plurality of reflectors is arranged at an end portion of the cover.
According to an embodiment of the present invention, the light sources of the plurality of light sources are light emitting diodes, LEDs.
According to an embodiment of the present invention, there is provided a lighting arrangement elongating along a principal axis, A. The lighting arrangement comprises a lighting device according to any one of the preceding embodiments, wherein the lighting device is arranged at a first end portion of the lighting arrangement. The lighting arrangement further comprises an electrical connection connected to the lighting device for a supply of current to the plurality of light sources, wherein the electrical connection is arranged at a second end portion, opposite the first end portion, of the lighting arrangement. The present embodiment is advantageous in that the lighting device according to the invention may be conveniently arranged in substantially any lighting arrangement, such as a LED lamp, luminaire, lighting system, or the like.
Further objectives of, features of, and advantages with, the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims. Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following.
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.
The second set of light sources 150 of the lighting device 100 is arranged outside the plurality of reflectors 130, and the light sources 110 of the second set of light sources 150 are arranged at respective peripheral portions of the cover 120. In the exemplifying configuration of the lighting device 100 in
The lighting device 100 in
The first set of light sources 140 may be configured to provide light having a first color temperature, CT1, and the second set of light sources 150 may be configured to provide light having a second color temperature, CT2. The difference in color temperature between the first and second color temperatures may be 300-1200 K, more preferably 500-1100 K, and most preferred 700-1000 K. It will be appreciated that the first and second color temperatures 140, 150 may be the same. Furthermore, the first and second color temperatures 140, 150 may be in the range of 1800-5000 K, more preferably in a range of 1900-4000 K, and even more preferred in a range of 2000-3500 K. The first and second color temperatures 140, 150 may have a color rendering index of at least 80.
The reflectors 130 may have a reflectance of >80%, more preferably >85%, and even more preferred 90%. The cover 120 may have a reflectance in the range of 20-70%, more preferably 25-60%, and even more preferred 30-50%. Furthermore, the cover 120 may have an absorption which is less than 3%, such as 1% or even <1% during operation of the lighting device 100.
In
It will be appreciated that the control unit 160 of the lighting device 100 may control the light emitted from the light sources 110 of the first and second sets of light sources 140, 150 from the example of
In
At the right hand portion of
The operation of the lighting arrangement 800 corresponds to that exemplified in
The cover 120 of the lighting arrangement 800 comprises a plurality of apertures 200, which is visible by
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. For example, one or more of the cover 120, the reflector(s) 130, the first and/or second set of light sources 140, 150, etc., may have different shapes, dimensions and/or sizes than those depicted/described.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20150036 | Jan 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/086300 | 12/15/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2021/136656 | 7/8/2021 | WO | A |
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| Number | Date | Country | |
|---|---|---|---|
| 20220381420 A1 | Dec 2022 | US |
