RGB LED architecture for color controllable LED filament

Abstract

An LED filament device is provided with a LED filament that has a plurality of sources of light. The sources of light are configured in an k*1 array with k=2 columns, and the array has a first set of at least 20 sources of light distributed over the columns. In a first column of the first set at least 90% of the total number of sources of light are selected from the group of (i) first sources of light and fifth sources of light. In a second column of the first set at least 80% of the total number of sources of light are selected from the group of second sources of light, third sources of light and fourth sources of light.

Claims

1. A LED filament device comprising: a LED filament having a plurality of sources of light, wherein: the sources of light are configured in an k*l array with k=2 columns, the array having a first set of at least 20 sources of light distributed over the columns, and the sources of light having solid state light sources; in a first column of the first set, at least 90% of a total number of sources of light are selected from a group consisting of first sources of light and fifth sources of light, with at least 40% of the total number of sources of light having first sources of light, and with 0-60% of the total number of sources of light having fifth sources of light; in a second column of the first set, at least 80% of the total number of sources of light are selected from a group consisting of second sources of light, third sources of light, and fourth sources of light, and in the second column of the first set at least 20% of the total number of sources of light has second sources of light, at least 20% of the total number of sources of light has third sources of light, and at least 20% of the total number of sources of light has fourth sources of light; the first sources of light are configured to generate first light having a first correlated color temperature (CCT1), the second sources of light are configured to generate second light having a second correlated color temperature (CCT2), the third sources of light are configured to generate blue third light, the fourth sources of light are configured to generate green fourth light, and the fifth sources of light configured to generate red fifth light; and CCT1 is selected from a range of at maximum 2400 K, CCT2 is selected from a range of at least 2700 K, and CCT2-CCT1500 K.

2. The LED filament device according to claim 1, wherein in an operational mode, the first sources of light in the first set and the third sources of light and fourth sources of light in the first set are together configured to provide white device light having a correlated color temperature selected from a range of 2700-4000K.

3. The LED filament device according to claim 1, wherein CCT1 is selected from a range of at maximum 1900-2400 K, CCT2 is selected from a range of 2700-6500 K, and CCT2-CCT11000 K.

4. The LED filament device according to claim 1, wherein more than 90% of a total number of fifth sources of light in the first set are configured in the first column of the array.

5. The LED filament device according to claim 1, wherein in an operational mode, the first sources of light, the third sources of light, the fourth sources of light, and the fifth sources of light are together configured to provide white light having a correlated color temperature selected from a range of 2700-4000 K.

6. The LED filament device according to claim 1, wherein the first sources of light and the fifth sources of light are configured in an (AE).sub.m1 configuration, wherein A represents the first sources of light, E represents the fifth sources of light, and m12, wherein between the respective first source of light and the respective fifth source of light for each AE configuration there is at maximum one other source of light.

7. The LED filament device according to claim 1, wherein the second sources of light, the third sources of light, and the fourth sources of light are configured in one or more of (i) an (BDC).sub.m2 configuration and (ii) an (BCBD).sub.m3 configuration, B represents the second sources of light, C represents the third sources of light, and D represents the fourth sources of light.

8. The LED filament device according to claim 1, wherein a plurality of couples of each of a second source of light and a fifth source of light are configured in rows.

9. The LED filament device according to claim 4, wherein the first sources of light have a first pitch (P1) and the fifth sources of light have a fifth pitch (P1), wherein P5P1.

10. The LED filament device according to claim 4, wherein a number n3 of third sources of light, a number n4 of fourth sources of light, and a number n5 of fifth sources of light mutually differ at maximum within 15% of an average value for n3, n4, and n5.

11. The LED filament device according to claim 4, further comprising a luminescent material; wherein the first sources of light are based on (a) first light sources configured to generate first light source light, and (b) the luminescent material, configured downstream of the first light sources and configured to convert at least part of the first light source light into luminescent material light; wherein the first light comprises the first light source light and the luminescent material light; and wherein the first light sources comprise solid state light sources.

12. The LED filament device according to claim 11, wherein the fifth sources of light comprise fifth light sources, the fifth light sources are configured to generate fifth light source light, the fifth light has the fifth light source light; wherein the LED filament device has a light transmissive material, the luminescent material is embedded in the light transmissive material, the light transmissive material is configured downstream of both the first light sources and the fifth light sources, the light transmissive material is transmissive for the fifth light source light; and wherein the fifth light sources comprise solid state light sources.

13. The LED filament device according to claim 1, wherein the LED filament has a spiral shape or a helical shape.

14. The LED filament device according to claim 1, wherein the LED filament device is configured to generate LED filament device light; wherein the LED filament device further comprises a control system configured to control one or more of a spectral power distribution, color rendering index, correlated color temperature, and color point of the filament device light by individually controlling one or more of the first sources of light, the second sources of light, the third sources of light, the fourth sources of light, and optionally the fifth sources of light.

15. A lighting device, wherein the lighting device is a retrofit lamp comprising a light transmissive envelope enclosing at least part of the LED filament device according to claim 1.

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-1e schematically depict embodiments and some aspects;

(3) FIGS. 2a-2c also show aspects and embodiments; and

(4) FIG. 3 schematically depict a further embodiment.

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

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) FIG. 1a schematically depicts an embodiment of a LED filament device 1000 comprising a LED filament 1100. The LED filament 1100 comprises a plurality of sources of light 100. IN embodiments, the plurality of sources of light 100 comprises first sources of light 110, second sources of light 120, third sources of light 130, and fourth sources of light 140. Also fifth sources of light may be possible, see below. The LED filament 1100 may have a length L1 along a length axis (see dashed line).

(7) Especially, the sources of light 110,120,130,140 may be configured in an k*l array 400 with k=2 columns 410,420 and each 110 sections 405. Here, there are 212 section 405.

(8) In embodiments, the array 400 may comprise at least a single first set 401 of at least 1.sub.1 sections 405 in each of the columns 410,420. Especially, wherein 1.sub.1=10. Hence, the first set 401 includes a first column (part) with 10 sections 405, and a second column (part) with also 10 sections 405.

(9) Here, the first set 401 may comprise at least 10 sources of light 100 in the first column 410 and at least 10 source of light 100 in the second column 410. In this embodiment, all sources of light 100 may be considered to be in the first set.

(10) In embodiments, each section comprises a light source, especially a solid state light source (see also below).

(11) As schematically depicted, in embodiments for the first set 401 may apply one or more of, especially all of: (a) more than 50% of a total number of n1 first sources of light 110 in the first set 401 are configured in a first column 410 of the array 400, (b) more than 50% of each of n2 second sources of light 120, n3 third sources of light 130, and n4 fourth sources of light 140 in the first set 401 are configured in a second column 420 of the array 400. Further, especially in embodiments may apply one or more of, especially all of; (i) n14, (ii) n22, (iii) n32, and (iv) n42.

(12) Reference 100 refers to the sources of light in general.

(13) Reference P refers to the pitch of the sources of light 100. Note that effectively the pitches P may be the pitch of the solid state light sources of the sources of light 100. Reference P1 refers to the pitch between the first sources of light 110. Note that effectively the pitch P1 may be the pitch of the respective solid state light sources of the first sources of light. Likewise, reference P2 refers to the pitch between the second sources of light 120. Note that effectively the pitch P2 may be the pitch of the respective solid state light sources of the second sources of light. Reference P3 refers to the pitch between the third sources of light 130. Note that effectively the pitch P3 may be the pitch of the respective solid state light sources of the third sources of light. Reference P4 refers to the pitch between the fourth sources of light 140. Note that effectively the pitch P4 may be the pitch of the respective solid state light sources of the fourth sources of light. Especially, in embodiments P3>P and P4>P. Further, in embodiments P2>P.

(14) FIG. 1b schematically shows a perspective view. Note that the sources of light 100 are not depicted in detail, and the cubes only schematically depict the sources of light 100. Other shapes may also be possible, as well as the combination with a coating layer with a phosphor (see also below).

(15) Here, the first set 401 may comprise at least 10 sources of light 100 in the first column 410 and at least 10 source of light 100 in the second column 410. In this embodiment, all sources of light 100 may be considered to be in the first set.

(16) FIG. 1b schematically depicts an embodiment wherein the first sources of light 110 are configured to generate first light 1.sub.11 having a first correlated color temperature CCT1, the second sources of light 120 are configured to generate second light 121 having a second correlated color temperature CCT2, the third sources of light 130 are configured to generate blue third light 131, and the fourth sources of light 140 are configured to generate green fourth light 141.

(17) Especially, in embodiments CCT1 is selected from the range of at maximum 2400 K, CCT2 is selected from the range of at least 2300 K, and CCT2-CCT1500 K. Especially, in embodiments CCT1 may be selected from the range of at maximum 1900-2400 K, CCT2 is selected from the range of 2500-6500 K, and CCT2-CCT11000 K.

(18) For instance, in embodiments in an operational mode the first sources of light 110 in the first set 401 and the third sources of light 130, and fourth sources of light 140 in the first set 401 are together configured to provide white device light 1001 having a correlated color temperature selected from the range of 2700-4000 K.

(19) FIG. 1c schematically depicts an embodiment also including fifth sources of light. Hence, in embodiments the LED filament device 1000 may further comprising fifth sources of light 150 configured to generate red fifth light 151. Especially, for the first set 401 applies: more than 50% of a total number of n5 fifth sources of light 150 in the first set 401 are configured in the first column 410 of the array 400. Further, in embodiments n52. Here only part of the set 401 is indicated, but see further also e.g. FIG. 1a.

(20) Here, the first set 401 may comprise at least 10 sources of light 100 in the first column 410 and at least 10 source of light 100 in the second column 410. In this embodiment, all sources of light 100 may be considered to be in the first set.

(21) In embodiments, in an operational mode the first sources of light 110, the third sources of light 130, the fourth sources of light 140, and the fifth sources of light 150 are together configured to provide white light (1001) having a correlated color temperature selected from the range of 2700-4000 K.

(22) Referring to FIG. 1c, in embodiments a plurality of couples (within the first set 401) of each a second source of light 120 and a fifth source of light 150 are configured in rows 407.

(23) Especially, in embodiments the first sources of light 110 have a first pitch P1 and wherein the fifth sources of light have a fifth pitch P1. In embodiments, P5P1. In other embodiments, P5P1. Further, in embodiments in embodiments P2>P.

(24) Further, in embodiments n3, n4, and n5 mutually differ at maximum within 15% of an average value for n3+n4+n5. However, other ratios may also be possible, see also above, like e.g. 2:1:1 (such as herein depicted).

(25) Referring to FIGS. 1b and 1c (and also 2c), the filament device light 1001 may comprise one or more of first light 1.sub.11, second light 121, third light 131, fourth light 141, and optionally fifth light 151.

(26) Referring to amongst others FIG. 1d (but see also FIGS. 2a-2c), in embodiments the LED filament device 1000 may further comprise a luminescent material 200.

(27) FIG. 1d schematically depicts two embodiments. Both the first embodiment I and the second embodiment II schematically depict embodiments based on a light source, especially a solid state light source, and luminescent material 200. To distinguish the embodiments, the light sources are indicated with references 10 and 20, respectively, and the luminescent materials 200 and their luminescent material light 201, are indicated with 200, 200, and 201, and 201, respectively.

(28) In embodiment I, the first sources of light 110 may be based on a first light sources 10 configured generate first light source light 11, and a luminescent material 200, i.e. 200, configured downstream of the first light sources 10 and configured to convert at least part of the first light source light 11 into luminescent material light 201, i.e. 201. Further, the first light 1.sub.11 may comprise the first light source light 11 and the luminescent material light 201, i.e. 201. Especially, the first light sources 10 comprise solid state light sources.

(29) In embodiment II, the second sources of light 120 may be based on a second light sources 20 configured generate second light source light 21, and a luminescent material 200, i.e. 200, configured downstream of the second light sources 20 and configured to convert at least part of the second light source light 21 into luminescent material light 201, i.e. 201. Further, the second light 121 may comprise the second light source light 21 and the luminescent material light 201, i.e. 201. Especially, the second light sources 20 comprise solid state light sources.

(30) In embodiments, the first light sources and second light sources may be from the same bin. Even more especially, the first light sources, the second light sources, and third light sources may be of the same bin. However, especially the luminescent materials for the first source of light and the second source of light are different. Hence, luminescent materials 200 and 200 may be different. In this way, the first light 1.sub.11 and the second light 121 may have substantially different CCTs.

(31) Referring to the second light, in embodiments the LED filament device may further comprise a luminescent material (200), wherein the second sources of light are especially based on (a) second light sources (20) configured generate second light source light (21), and (b) the luminescent material (200), configured downstream of the second light sources (20) and configured to convert at least part of the second light source light (21) into luminescent material light (201). Especially, in embodiments the second light (121) comprises the second light source light (21) and the luminescent material light (201). Further, as indicated above, in embodiments the second light sources (20) comprise solid state light sources. In this way, the second source of light may be based on a luminescent material.

(32) FIG. 1e schematically depicts an embodiments wherein the sources of light 100 are not configured in rows being shared by both columns 410,420, but the sources of light 100 in one column are offset relative to the sources of light in the other column. Note that nevertheless the pitches may be the same. However, in other embodiments the pitches between the sources of light in the different columns may also be different.

(33) FIG. 2a schematically depict some reference examples of LED filaments 1000. Embodiment I may schematically depict a LED filament with a single column, with the solid state light sources embedded in luminescent material, thereby providing a plurality of sources of light 100. The LED filament of embodiment I may be configured to provide white light with a relatively low CCT, such as equal to or below 2300 K. Embodiment I may at lower intensities show spottiness.

(34) FIG. 2a, embodiment II, may be essentially the same as embodiment I, with the different that the LED filament includes two columns, with the second column with the solid state light sources embedded in luminescent material, thereby providing a plurality of sources of light 100. This additional column may be configured to provide white light with a relatively high CCT, such as equal to or larger than 4000 K. When individually controlled, different CCT between the highest and the lowest CCT may be provided. However, the white light may not always be desirable close enough to the BBL. Embodiment II may at lower intensities show spottiness.

(35) To solve the latter issue, embodiment III may be proposed, wherein a third column is provided with RGB solid state light sources. In this way, the BBL may be better followed and the color gamut may be larger. Embodiment I II may at lower intensities show spottiness. Further, the width of the filament may be relatively large, which may be less desirable.

(36) Embodiment IV is essentially the same as embodiment I, but now with a smaller pitch. This may reduce spottiness. However, there may essentially be no tunability of the spectral power distribution.

(37) FIG. 2b, embodiments V-X schematically depict a number of embodiments which may address one or more of the above indicated problems.

(38) In embodiment V, the first column 410 comprises first sources of light and the second column 420 comprises second sources of light 120, third sources of light 130, the fourth sources of light 140. This may provide a relatively slim variant with reduced or no spottiness.

(39) Embodiment VI is a variant on embodiment V, with relatively more second sources of light 120.

(40) Referring to embodiments VI and VII, the second sources of light 120 (in the first set 401), the third sources of light 130 (in the first set 401), and the fourth sources of light 140 (in the first set 401) may be configured in one or more of (i) an (BDC).sub.m2 configuration, see embodiment V, and (ii) an (BCBD).sub.m3 configuration, see embodiment VI, wherein B represents the second sources of light 120, C represents the third sources of light 130, D represents the fourth sources of light 140. For instance, m22, and m32.

(41) Embodiments VII-X include embodiments wherein fifth sources of light 150 are provided. This may enlarge the color gamut and may allow higher CRIs. Further, when reducing intensity, still spottiness may be reduced or essentially absent.

(42) Embodiments VII and VIII on the one hand and VI on the other hand are essentially similar with respect to the second column. In embodiment VIII the first sources of light 150 and the second sources of light 120 are aligned. Hence, a plurality of couples (within the first set 401) of each a second source of light 120 and a fifth source of light 150 are configured in rows 407.

(43) Referring to embodiments VII-X, the first sources of light 110 and the fifth sources of light 150 may be configured in an AE.sub.m1 configuration, wherein A represents the first sources of light 110, E represents the fifth sources of light 150, and wherein m12, wherein for each AE configuration applies that between the respective first source of light 110 and the respective fifth source of light 150 there is at maximum one other source of light 100.

(44) Referring to embodiment X, but also in combination with FIGS. 1c and 1d, and FIG. 2a-2c, the fifth sources of light 150 comprise fifth light sources 50, wherein the fifth light sources 50 are configured to generate fifth light source light 51, wherein the fifth light 151 comprises the fifth light source light 51 (like having one or more wavelengths selected from the wavelength range 610-650 nm). Especially, the LED filament device 1000 may comprise a light transmissive material 145 wherein the luminescent material 200 is embedded, wherein the light transmissive material 145 (with the luminescent material 200 embedded therein) is configured downstream of both the first light sources 10 and the fifth light sources 50. The light transmissive material 145 (with the luminescent material 200 embedded therein) may be transmissive for the fifth light source light 51. Especially, the fifth light sources 50 comprise solid state light sources.

(45) Referring to embodiments V-X, in fact all sources of light 100 are aligned in rows 407 over the columns 410,420.

(46) FIG. 2c schematically depicts how e.g. embodiment VIII of FIG. 2b could be operated. In embodiment I, only the third sources of light 130 provide third light 131 (blue).

(47) In embodiment II, only the fourth sources of light 140 provide third light 141 (green).

(48) In embodiment III, only the fifth sources of light 150 provide third light 151 (red).

(49) In embodiment IV, only the first sources of light 110 and the fifth sources of light 150 provide first light 1.sub.11 and fifth light 151. This may provide warm white, or even extreme warm white. In embodiment V, only the second sources of light 120 provide second light 121 (cool white).

(50) FIG. 3 schematically depicts an embodiment of an application of the LED filament device 1000 and/or the lighting device 1200. The lighting device light is indicated with reference 1201, which may consist of the filament device light 1001 (of one or more LED filament devices 1000). The lighting device 1200 may comprise a light transmissive envelope enclosing at least part of the LED filament device 1000.

(51) In embodiments the LED filament device 1000 may further comprise a control system 300 configured to control a color point of the filament device light 1001, or the control system 300 may be functionally coupled to the LED filament device 1000.

(52) FIG. 3 also schematically depicts an embodiment of a lighting device 1200, comprising the LED filament device 1000. The lighting device 1200 may be a retrofit lamp. Further, an embodiment is depicted wherein the filament 1100 has a spiral shape or a helical shape.

(53) Referring to FIG. 3, and also FIGS. 1c, and 2b, in embodiments the LED filament device 1000 is configured to generate LED filament device light 1001. The LED filament device 1000 may thus further comprise a control system 300 configured to control one or more of a spectral power distribution, color rendering index, correlated color temperature, and color point of the filament device light 1001 by individually controlling one or more of the first sources of light 110, the second sources of light 120, the third sources of light 130, the fourth sources of light 140, and optionally the fifth sources of light 150.

(54) The term plurality refers to two or more. 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%. The term comprise also includes embodiments wherein the term comprises means consists of.

(55) 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.

(56) 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.

(57) 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.

(58) 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.

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

(60) 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.

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

(62) 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.

(63) 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.

(64) 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.

(65) 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.