Abstract
A lighting device (1) is provided. The lighting device comprises at least two light-emitting diode, LED, filaments (11). The lighting device further comprises at least two optical modules (12). Each optical module (12) is arranged in relation to a corresponding one of the LED filaments (11) to receive light emitted by the corresponding one of the LED filaments (11). Each optical module (12) is configured to collimate the received light and produce a collimated light beam so as to increase the degree of collimation of the light produced by the optical module (12) as compared to the light received by the optical module (12). The light produced by each optical module (12) is emitted from the lighting device (1). Further, the optical modules (12) are arranged in relation to each other such that collimated light beams of the respective ones of the optical modules (12) are oriented in different directions.
Claims
1. A lighting device comprising: at least two light-emitting diode, LED, filaments; and at least two optical modules, each optical module being arranged in relation to a corresponding one of the LED filaments to receive light emitted by the corresponding one of the LED filaments; wherein each optical module is configured to collimate the received light and produce a collimated light beam so as to increase the degree of collimation of the light produced by the optical module as compared to the light received by the optical module, wherein the light produced by each optical module is emitted from the lighting device, wherein the optical modules are arranged in relation to each other such that collimated light beams of the respective ones of the optical modules are oriented in different directions, and wherein each or any of the at least two optical modules comprise or be constituted by, or be configured as, a lens.
2. A lighting device according to claim 1, wherein the optical modules are arranged in relation to each other such that a collimated light beam produced by one optical module does not overlap with a collimated light beam produced by another optical module.
3. A lighting device according to claim 1, wherein the number of LED filaments and optical modules is in the range from 3 to 14.
4. A lighting device according to claim 1, wherein each of the at least two optical modules is arranged at an angle Θ in relation to a longitudinal axis (A) of the lighting device, wherein Θ is different from 0.
5. A lighting device according to claim 1, further comprising a controller, configured to individually control at least one of an intensity and a color of the light emitted by each LED filament.
6. A lighting device according to claim 1, wherein each of the at least two optical modules comprises a reflector.
7. A lighting device according to claim 6, wherein the at least two reflectors are elongated and the at least two LED filaments are arranged in the elongated direction of its corresponding reflector.
8. A lighting device according to claim 6, wherein each of the at least two reflectors comprises a parabolic reflector.
9. A lighting device according to claim 6, wherein each of the at least two reflectors comprises a trapezoidal shape.
10. A lighting device according to claim 6, wherein each LED filament is arranged in an optical center of its corresponding optical module.
11. A lighting device according to claim 1, wherein the at least two optical modules are comprised in a monolithic optical element.
12. A lighting device according to claim 6, wherein each of the at least two reflectors has a length Lr, in the range from 2 to 12 cm, and/or each of the at least two LED filaments has a length Lf, in the range from 0.5Lr to 0.95Lr.
13. A lighting device according to claim 1, wherein the lighting device further comprises a light transmissive envelope and a cap.
14. A lighting device according to claim 1, wherein the full width at half maximum of the collimated light beam produced by each optical module is in the range of 360°/(N*2) to 360°/(N), wherein N is the number of optical modules.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] Exemplifying embodiments of the invention will be described below with reference to the accompanying drawings.
[0043] FIG. 1 is a schematic view of a cross-section of a lighting device perpendicular to a longitudinal axis of the lighting device, according to one or more exemplifying embodiments of the present invention.
[0044] FIGS. 2a-2d are schematic views of four cross-sections of lighting devices perpendicular to longitudinal axes of the lighting devices according to an exemplifying embodiment of the present invention.
[0045] FIGS. 3a-3b are schematic views of a lighting device according to one or more exemplifying embodiments of the present invention.
[0046] FIG. 3c is a schematic view of an optical module an LED filament according to one or more exemplifying embodiments of the present invention.
[0047] FIG. 4 is a schematic view of a monolithic optical element and LED filaments according to an exemplifying embodiment of the present invention.
[0048] FIGS. 5 and 6 are schematic views of a cross-section of a lighting device perpendicular to a longitudinal axis of the lighting device, according to exemplifying embodiments of the present invention.
[0049] All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate embodiments of the present invention, wherein other parts may be omitted or merely suggested.
DETAILED DESCRIPTION
[0050] The present invention will now be described hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments of the present invention set forth herein; rather, these embodiments of the present invention are provided by way of example so that this disclosure will convey the scope of the invention to those skilled in the art. In the drawings, identical reference numerals denote the same or similar components having a same or similar function, unless specifically stated otherwise.
[0051] FIG. 1 is a schematic view of a cross-section of a lighting device 1 in a plane perpendicular to a longitudinal axis of the lighting device 1, according to one or more exemplifying embodiments of the present invention. FIG. 1 shows a lighting device 1 comprising six LED filaments 11 and one monolithic optical element 22, which comprises six optical modules 12. It should be noted that the number of LED filaments 11 is purely exemplary, and that the inventive concept is in no way limited by the illustration. For example, the lighting device may comprise any number of LED filaments 11, it may for example be in the range from 3 to 14, from 5 to 12, or from 6 to 10. Each LED filaments 11 is arranged inside an optical center of a corresponding optical module 12. The number of optical modules comprised in the lighting device 1 is not limited to the number shown in FIG. 1. The number of optical modules comprised in the lighting device 1 may for example be in the range from 3 to 14, from 5 to 12, or from 6 to 10. The monolithic optical element 22 is arranged in the center of the lighting device 1. The two right-most LED filaments 11 are shown with five dashed arrows, which represents emitted rays of light, extending from their respective LED filaments 11. Out of the five illustrated dashed arrows, two can be seen to be received by an optical module 12. The dashed arrows, representing emitted rays of light, is then seen to be collimated by the optical module 12, which is configured as a reflector. The lighting device 1 is illustrated as being arranged inside a light transmissive envelope, which in accordance with the illustrated embodiment of the present invention is comprised in or constituted by a light bulb 14. The lighting device 1 may hence be comprised in a light bulb 14.
[0052] FIG. 2a-2d are schematic views of four cross-sections of lighting devices 1 perpendicular to longitudinal axes of the lighting devices 1 according to an exemplifying embodiment of the present invention. FIG. 2a shows a lighting device 1 comprising eight LED filaments 11 and one monolithic optical element 22, which comprises eight optical modules 12. Each LED filaments 11 is arranged inside an optical center of a corresponding optical module 12. The monolithic optical element 22 is arranged in the center of the lighting device 1. Further, FIG. 2a shows eight arrows arranged from a respective LED filament 11 in an outward direction with regards to a central axis of the lighting device 1. It should be noted that the numbers of LED filaments 11 and optical modules 12 is purely exemplary, and is not limited to eight. There number of LED filaments and/or optical modules may for example be in the range from 3 to 14, or 5 to 12, or 6 to 10. The optical modules 12 are illustrated in FIGS. 2a-2d as being configured as parabolic reflectors. However, the optical modules 12 are not limited thereto, and may be configured as reflectors (parabolic reflectors or some other type of reflectors) and/or lenses, for example. FIG. 2b shows a lighting device 1 comprising all the features of the lighting device 1 shown in in FIG. 2a, except that every other arrow, arranged from a respective LED filament 11 in an outward direction with regards to a central axis of the lighting device 1, has a smaller size. The differing size of arrows may indicate a collimated light beam pattern with regards to collimated light beam intensity. FIG. 2c shows a lighting device 1 comprising all the features of the lighting device 1 shown in in FIG. 2a and FIG. 2b, except that every other LED filament 11 is in an off-state. FIG. 2d shows a lighting device 1 comprising all the features of the lighting device 1 shown in in FIGS. 2a-2c, except that every other arrow, arranged from a respective LED filament 11 in an outward direction with regards to a central axis of the lighting device 1, is emitting light with a different color than the other LED filaments 11. Thereby, a collimated light beam pattern with regards to color is shown. Similar to the lighting device 1 illustrated in FIG. 1, the lighting devices 1 illustrated in FIGS. 2a-2d are arranged inside a light transmissive envelope, which in accordance with the illustrated embodiments of the present invention is comprised in or constituted by a light bulb 14.
[0053] FIG. 3a-3b are schematic views of a lighting device 1 according to one or more exemplifying embodiments of the present invention. FIG. 3a shows a lighting device 1 comprising at least two LED filaments 11 and at least two optical modules 12, which are shown to be arranged inside a light bulb 14. The at least two optical modules 12 are shown to be elongated and the at least two LED filaments are shown to be arranged in the elongated direction of its corresponding reflector. The shown light bulb has the appearance of a traditional incandescent light bulb, and is configured to be mounted in a conventional socket. However, the light-emitting filament wire of a traditional incandescent light bulb is shown to have been replaced by the at least two LED filaments 11 and at least two optical modules 12. The lighting device 1 illustrated in FIGS. 3a and 3b comprises a base 15, which for example may comprise an Edison screw base, as illustrated, or a bayonet fitting, or another type of connection known in the art. In accordance with the embodiments of the present invention illustrated in FIGS. 3a and 3b, the lighting device 1 may comprise some supporting structure 16 for supporting the LED filaments 11 and the optical modules 12 and possibly some other component(s) that may be included in the lighting device 1. Further, the lighting device 1 may include circuitry (not shown in FIGS. 3a-3c) capable of converting electricity from a power supply to electricity suitable to operate or drive the at least two LED filaments. The circuitry may be capable of at least converting between Alternating Current and Direct Current and converting voltage into a suitable voltage for operating or driving components of the lighting device, such as LED filaments. The at least two LED filaments 11 and at least two optical modules 12 are arranged parallel to a longitudinal axis of the lighting device 1. Each optical module 12 is shown to be arranged between a central axis of the lighting device 1 and a respective LED filament 11. FIG. 3b comprises all features shown in FIG. 3a. Further, FIG. 3b discloses the two LED filaments 11 and the two optical modules 12 as arranged at an angle θ in relation to a longitudinal axis of the lighting device 1. The lower parts of the two LED filaments 11 and the two optical modules 12 are shown as being arranged at a distance from the central axis of the lighting device 1 which is greater than the distance between the upper parts of the two LED filaments 11 and the two optical modules 12 and the central axis of the lighting device 1.
[0054] FIG. 3c is a schematic view of an optical module 12 and a LED filament 11 according to one or more exemplifying embodiments of the present invention. To the left, FIG. 3c shows a LED filament 11 and an optical module 12, wherein the optical module 12 has a trapezoidal shape. The optical module 12 is shown to be configured to have a parabolic shape. Additionally, to the right of FIG. 3c the LED filament 11 and optical module 12 configuration is shown in two schematic views, one upper-right schematic view and one lower-right schematic view, both which show a cross-sectional view of the LED filament 11 and optical module 12 configuration. The upper-right schematic view shows a cross-section of the LED filament 11 and an optical module 12, wherein the optical module 12 has a trapezoidal shape. The LED filament 11 is shown in the upper-right schematic view to be arranged with regards to the parabolic trapezoidal-shaped optical module 12 at a distance d1, such that the LED filament 11 is arranged in an optical center of the optical module 12.
[0055] The lower-right schematic view shows a cross-section of the LED filament 11 and an optical module 12, wherein the optical module 12 has a trapezoidal shape. The LED filament 11 is shown in the lower-right schematic view to be arranged with regards to the parabolic trapezoidal-shaped optical module 12 at a distance d2, such that the LED filament 11 is arranged in an optical center of the optical module 12, and where d2>d1. The LED filament 11 is thereby shown in FIG. 3c to be arranged in relation to the optical module 12 such that the distance between the LED filament 11 and the optical module 12 is varying along the LED filament 11. The LED filament 11 may be tilted in relation to its respective optical module 12.
[0056] FIG. 4 is a perspective view of a monolithic optical element 22 and LED filaments 11 according to an exemplifying embodiment of the present invention. The illustrated monolithic optical element 22 is shown to comprise six optical modules 12. A LED filament 11 is shown as arranged in relation to a corresponding one of the optical modules 12. The monolithic optical element 22 is shown to have a hollow core. However, the optical element 22 may comprise a hole arranged through the monolithic optical element 22. The shown monolithic optical element 22 is exemplary and may comprise any number of optical modules 12 and not only six, such as, for example, in the range from 3 to 14, or 5 to 12, or 6 to 10.
[0057] FIG. 5 is a schematic view of a cross-section of a lighting device 1 perpendicular to a longitudinal axis of the lighting device 1, according to one or more exemplifying embodiments of the present invention. The lighting device 1 illustrated in FIG. 5 is similar to the lighting device 1 illustrated in FIG. 1. However, while the optical elements 12 in the lighting device 1 illustrated in FIG. 1 comprises reflectors, the optical elements 12 in the lighting device 1 illustrated in FIG. 5 comprises lenses. Possibly, the optical elements 12 may be comprised in a monolithic element, which may be arranged in a center of the lighting device 1. The lighting device 1 illustrated in FIG. 5 comprises six optical modules 12, wherein each LED filament 11 is arranged between a corresponding optical module 12 and the central axis A of the lighting device 1. While the six optical modules 12 in FIG. 5 are configured as lenses, any of the optical modules 12 could be configured as a reflector, for example, such as a parabolic reflector. Thus, the lighting device 1 may comprise several optical elements, wherein at least some may be of different type (e.g., reflector and lens), which applies to all embodiments disclosed herein. The number of optical elements 12 illustrated in FIG. 5 is exemplifying and could in principle be any number. The arrows in FIG. 5 illustrate light rays, and the angles α represent beam angles of the collimated light beams produced by two of the optical modules 12.
[0058] FIG. 6 is a schematic view of a cross-section of a lighting device 1 perpendicular to a longitudinal axis of the lighting device 1, according to one or more exemplifying embodiments of the present invention. The lighting device 1 illustrated in FIG. 6 is similar to the lighting device 1 illustrated in FIG. 1, and the same reference numerals denote the same or similar elements, having the same or similar function. FIG. 6 illustrates that each optical module 12 produces a respective collimated light beam. The arrows in FIG. 6 illustrate light rays, and the angles α, β, γ represent beam angles of the collimated light beams produced by three of the optical modules 12. When seen in the plane of the figure, the collimated light beams may have beam angles such that the sum of the beam angles is less than 360°. However, the sum of the beam angles may possibly be equal to or more than 360°. The collimated light beams in FIG. 6 are such that they are in different directions, such that none of the collimated light beams intersect each other.
[0059] In conclusion, a lighting device is provided. The lighting device comprises at least two LED filaments. The lighting device comprises at least two optical modules. Each optical module is arranged in relation to a corresponding one of the LED filaments to receive light emitted by the corresponding one of the LED filaments. Each optical module is configured to collimate the received light and produce a collimated light beam so as to increase the degree of collimation of the light produced by the optical module as compared to the light received by the optical module. The light produced by each optical module is emitted from the lighting device. The optical modules are arranged in relation to each other such that collimated light beams of the respective ones of the optical modules are oriented in different directions.
[0060] While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the appended 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. Any reference signs in the claims should not be construed as limiting the scope.
