A LED filament lamp based on phosphor-converted green LED filament and hybrid direct-emitting red-blue LED filament
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SIGNIFY HOLDING BV
- Filing Date
- 2024-06-24
- Publication Date
- 2026-05-13
Smart Images
Figure EP2024067593_09012025_PF_FP_ABST
Abstract
Description
[0001] A LED filament lamp based on phosphor-converted green LED filament and hybrid direct- emitting red-blue LED filament
[0002] FIELD OF THE INVENTION
[0003] The invention relates to LED filament lamp comprising at least two LED filaments, wherein the LED filament lamp comprises phosphor-converted LED filament and direct-emitting dual-color LED filament.
[0004] BACKGROUND OF THE INVENTION
[0005] A trend in lighting is LED filament lamps. An LED filament lamp, such as LED retrofit lamps or LED light bulbs, is a LED lamp which may be designed to resemble a traditional incandescent light bulb with a visible filament for aesthetic and light distribution purposes, but with the high efficiency of light-emitting diodes. LEDs filaments are available in all colors i.e., blue, green, red, and white LED filaments.
[0006] Most commercially available LED retrofit lamps may include one or more LED filament that provide white light with a single-color temperature, wherein LED filaments typically include one type of LEDs, e.g., blue or UV LEDs, covered by a luminescent coating, e.g., a polymer layer comprising a yellowish phosphor coating capable of providing yellow converted light based on blue or UV LEDs. When the light emitting from the blue or UV LEDs, is passing through the mixture of the yellowish phosphor coating, the converted light is distributed in the entire visible spectrum. The blue light emitted from the LED filament stimulates the blue receptors of the eye, and the yellow light stimulates the red and green receptors of the eye, such that the resulting mix of blue and yellow converted light gives the appearance of a white light.
[0007] When controlling a white light emitting from the LED filament lamp, the LED filament lamp may be controllable between a warm white light and a cool white light, being accomplished using a first LED filament emitting warm white light and a second LED filament emitting cool white light, and individually controlling the intensity of the individual LED filament relative to the preferred white light. Alternatively, when controlling a white light emitting from the LED filament lamp, the LED filament lamp may be controlled between warm white light and a cool white light accomplished using a first LED filament emitting warm white light and a second LED filament emitting additional red and blue light, and individually controlling the intensity of the individual LED filament and the red and blue light relative to the preferred white light.
[0008] US 2021 / 0018146 Al discloses an LED light bulb for proving light distribution of the LED flexible filament light bulb. The LED light bulb comprise at least two filaments. Each of the filament is capable of emitting light with a different light characteristic from each other. The LED filament includes a linear array of LEDs arranged on a carrier substrate, wherein the linear array is divided into two separate longitudinal sections, a first longitudinal section including only LEDs configured to emit white light, and a second longitudinal section including only color controllable LEDs configured to emit color controllable light, said color controllable LEDs comprise LED groups each including a red LED, a green LED, and a blue LED.
[0009] It is desired to improve the performance and / or the functionality of LED filaments for use in a LED filament lamp.
[0010] SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to overcome this problem, and to improve performance and / or functionality of LED filaments for use in a LED filament lamp.
[0012] These and other objects are achieved by providing a LED filament lamp configured to, in operation, provide lamp light, wherein the LED filament lamp comprises: at least one first LED filament emitting first LED filament light, and comprises a first elongated carrier having a first major surface and a second major surface arranged opposite each other, wherein the first major surface is adapted to receive a plurality of first blue LEDs configured to, in operation, emit first LED light being a first blue light, wherein said first blue LEDs are arranged in at least one first array on said first elongated carrier, wherein the plurality of first blue LEDs is covered by a first elongated encapsulant comprising a first luminescent material, configured to fully convert the first LED light into a first converted light, the first converted light being a first green light, such that the first LED filament (2) emits first green light at least one second LED filament emitting second LED filament light, and comprises a second elongated carrier having a third major surface and a fourth major surface arranged opposite each other, wherein the third major surface and / or the fourth major surface are adapted to receive: (i) a plurality of second blue LEDs configured to, in operation, emit second LED light being second blue light, and
[0013] (ii) a plurality of red LEDs configured to, in operation, emit third LED light being first red light, wherein the plurality of second blue LEDs and the plurality of red LEDs are arranged in at least one second array on said second elongated carrier, such that the second LED filament (3) emits second blue light and first red light.
[0014] The LED filament lamp is configured to provide lamp light emitting from the various LED filaments. LED filament lamp comprises a greenish phosphor-converted LED filament and a direct-emitting red-blue LED filament. LED filament lamp comprises at least one first LED filament and at least one second LED filament. The first LED filament and second LED filament are both elongated. When the light emits from the blue or UV LEDs, the light is passing through the mixture of the greenish phosphor coating, e.g. comprising one or more green phosphors, wherein the converted light is mainly distributed in a part of the visible light spectrum as a green light. The red-blue light emitted from the red-blue LED filament stimulates the relative blue and red receptors of the eye, and the converted green light stimulates the green receptors of the eye, such that the resulting mix of converted green light, the blue and red light gives the appearance of a white light.
[0015] Thereby, an improved performance and / or functionality of LED filaments for use in a LED filament lamp is achieved.
[0016] The first LED filament comprises a plurality of first blue LEDs configured to, in operation, emit first LED light being blue light. The first blue LEDs may be configured to emit first blue light having a dominant peak wavelength in a wavelength range from 400 nm to 480 nm. The first blue LEDs are arranged in at least one first array on a first elongated carrier. The first elongated carrier comprises a first major surface and a second major surface configured to receive LEDs. The first major surface and the second major surface are arranged, such that the first major surface and the second major surface are opposite each other. The plurality of first blue LEDs is arranged along the first elongated carrier on one or both first major surface and the second major surface. The first blue LEDs are covered by a first elongated encapsulant comprising a first luminescent material. The first elongated encapsulant may also at least partly cover at least one of the first major or second major surface, such that at least part of the first and optionally the second major surface may also be covered by the first elongated encapsulant comprising the first luminescent material. The encapsulant may be a polymer material, which may be rigid or flexible. The first luminescent material is configured to fully convert the first LED light into a first converted light. By the term fully, it should be understood as at least 95% of the first LED light is converted. The light converted may preferably be 98% of the light emitted from the first blue LEDs. The light converted may more preferably be 99% of the light emitted from the first blue LEDs. The light converted may preferably be 100% of the light emitted from the first blue LEDs. The first luminescent material is configured to convert the first LED light into a first converted light being a first green light. The first LED light may be converted into a first converted light being only green light. The converted light, which is converted from the first blue light emitting from the first blue LEDs, may preferably have a dominant peak wavelength in a wavelength range from 510 nm to 580 nm as green light.
[0017] The second LED filament comprises a plurality of second blue LEDs configured to, in operation, emit second LED light being a second blue light, and a plurality of red LEDs configured to, in operation, emit third LED light being red light. The second blue LEDs may be configured to emit second blue light having a dominant peak wavelength in a wavelength range from 400 nm to 480 nm. The red LEDs may be configured to emit third LED light being a first red light emitted having a dominant peak wavelength in a wavelength range from 600 nm to 680 nm. The plurality of second blue LEDs and the plurality of red LEDs are arranged in at least one second array on a second elongated carrier. The second elongated carrier comprise a third major surface and a fourth major surface. The second elongated carrier comprises a third major surface and a fourth major surface configured to receive LEDs. The third major surface and the fourth major surface are arranged such that the third major surface and the fourth major surface are opposite each other. The light emitted from the second LED filament may emit a second LED filament light being a second blue light or a first red light, or a light mixed with second blue light and first red light. The third plurality of blue LEDs is covered by a second encapsulant comprising a second luminescent material configured to convert the third blue light at least partially into a second converted light, and wherein the second converted light is green light, red light or a combination of green light and red light.
[0018] In an embodiment the at least one first LED filament and the at least one second LED filament are arranged at a distance from one another, wherein the distance is at least 5 mm.
[0019] The at least one first LED filament and the at least one second LED filament may be arranged at a minimum or an average distance from one another, when arranged inside the LED filament lamp. The distance may be at least 5 mm. The distance may preferably be at least 10 mm. The distance may more preferably be at least 13 mm. The distance may most preferably be at least 15 mm. The distance between the LED filaments may depend on the size and shape of the LED filament lamp. The distance between the LED filaments may depend on the size and shape of the LED filament which is arranged inside the LED filament lamp. The distance between the LED filaments may depend on the numbers of first and second filament, which is placed inside the LED filament lamp.
[0020] The obtained the effect of the latter two embodiments referring to the first and second LED filaments, the effect obtained is reduced crosstalk i.e., the first luminescent material, e.g. one or more green phosphors, is hardly or not excited by the blue light emitted by the at least one second LED filament.
[0021] In an embodiment the first LED filament further comprises a plurality of third blue LEDs configured to, in operation, emit a fourth LED light being a third blue light, wherein the plurality of third blue LEDs is arranged on said second major surface, opposite to said first major surface, of the first elongated carrier, wherein the plurality of third blue LEDs is covered by a second elongated encapsulant comprising a second luminescent material configured to fully convert the fourth LED light into a second converted light, and wherein the second converted light is a second green light having a peak emission wavelength higher than a peak emission wavelength of the first converted light.
[0022] The plurality of first blue LEDs may be arranged on the first major surface of the first elongated carrier. The first LED filament further comprises a plurality of third blue LEDs configured to, in operation, emit a fourth LED light being a third blue light. The plurality of third blue LEDs may be arranged on the second major surface, opposite the first major surface of the first elongated carrier.
[0023] The plurality of third blue LEDs may be covered by a second elongated encapsulant comprising a second luminescent material configured to fully convert the fourth LED light into a second converted light. The second converted light is a second green light having a peak emission wavelength higher than a peak emission wavelength of the first converted light.
[0024] In an embodiment the LED filament lamp further comprises a third LED filament configured to emit a third LED filament light, wherein the third LED filament comprises a plurality of fourth blue LEDs configured to, in operation, emit fifth LED light being a third blue light, wherein the plurality of fourth blue LEDs is arranged in at least one array on the third elongated carrier, wherein the plurality of fourth blue LEDs is covered by a third encapsulant comprising a third luminescent material configured to at least partially convert the third blue light into a third converted light, and wherein the third converted light is green light, red light or a combination of green light and red light.
[0025] The third LED filament comprises a plurality of fourth blue LEDs configured to, in operation, emit fifth LED light being a third blue light. The fourth blue LEDs may be configured to emit fifth LED light having a dominant peak wavelength in a wavelength range from 400 nm to 480 nm. The dominant peak wavelength fifth LED light may be equal to or different from the dominant peak wavelength of one of the first, second or fourth LED light. The plurality of fourth blue LEDs may be arranged in at least one array on the third elongated carrier. The plurality fourth of blue LEDs may be covered fully or partially by a third encapsulant comprising the third luminescent material. The third luminescent material converts the fifth LED light or part of the fifth LED light into a third converted light. The third converted light may be a third green light in a wavelength range from 500 nm to 580 nm. The third converted light may alternatively be red light in a wavelength range from 400 nm to 480 nm. The third converted light may also be a combination of additional green light and red light. When the plurality of fourth blue LEDs is partially covered by a third encapsulant comprising the third luminescent material, the third filament may emit both a fifth LED light, a converted green and red light. The third filament may be configured to provide a white light.
[0026] In an embodiment the plurality of second blue LEDs and the plurality of red LEDs are arranged alternatingly on said third major surface of the second elongated carrier, or the plurality of second blue LEDs and the plurality of red LEDs are arranged alternatingly on said third major surface and on said fourth major surface of the second elongated carrier, or the plurality of second blue LEDs is arranged on said third major surface of the second elongated carrier and the plurality of red LEDs are arranged on said fourth major surface of the second elongated carrier.
[0027] The plurality of second blue LEDs and the plurality of red LEDs may be arranged alternatingly on the third major surface of the second elongated carrier. The plurality of second blue LEDs and the plurality of red LEDs may be arranged alternatingly on the fourth major surface of the second elongated carrier, opposite the third major surface. The plurality of second blue LEDs and the plurality of red LEDs may alternatively be arranged alternatingly on the third major surface and on said fourth major surface of the second elongated carrier, as another option, the plurality of second blue LEDs may be arranged on the third major surface of the second elongated carrier and the plurality of red LEDs may be arranged on the fourth major surface of the second elongated carrier. In an embodiment the second LED filament comprises a third encapsulant comprising a light scattering material configured to scatter the second LED light into second scattered light and the third LED light into third scattered light, wherein said third encapsulant covers said plurality of second blue LEDs and said plurality of red LEDs.
[0028] The second LED filament may comprise a third encapsulant comprising a light scattering material. The third encapsulant may be free from a luminescent material. Thereby the second LED filament may be free from a luminescent material. The light scattering material may be configured to scatter the second LED light into second scattered light and the third LED light into third scattered light. The third encapsulant covers the plurality of second blue LEDs and the plurality of red LEDs fully or partially. The light scattering material may provide the second scattered light as a blue scattered light. The light scattering material may provide the third scattered light as a red scattered light.
[0029] In an embodiment the one or more of the first elongated carrier, the second elongated carrier and, where provided, the third elongated carrier are translucent, and said respective elongated carriers are configured to at least partly transmit a LED light, which LED light comprises direct light and / or converted light.
[0030] One or more of the first elongated carrier and the second elongated carrier and, where provided, the third elongated carrier may translucent. The carrier or carriers may be reflective or light transmissive. The carrier or carriers may be translucent. The carrier or carriers may preferably be transparent. The carrier or carriers may be rigid, for example made from a polymer, glass, quartz, metal, or sapphire or similar. Alternatively, the carrier or carriers may be flexible, e.g., made of a polymer or metal e.g., a film or foil or similar.
[0031] In an embodiment the first LED filament is obliquely arranged with respect to the second LED filament, and wherein an axis of elongation of the first LED filament and an axis of elongation of the second LED filament are not arranged in a plane; and where provided, wherein the third LED filament is obliquely arranged with respect to the second LED filament, and wherein an axis of elongation of the third LED filament and an axis of elongation of the second LED filament are not arranged in a plane.
[0032] The first LED filament may be obliquely arranged with respect to the second LED filament. Preferably, an axis of elongation of the first LED filament and an axis of elongation of the second LED filament may not be arranged in a similar plane. When provided the third LED filament may be obliquely arranged with respect to the second LED filament, and wherein an axis of elongation of the third LED filament and an axis of elongation of the second LED filament may not be arranged in the same or a parallel plane. When provided the third LED filament may be obliquely arranged with respect to both the first and the second LED filament, and wherein axis of elongation of the third LED filament and preferably the axis of elongation of the first and the second LED filament may not be arranged in a plane. The obtained effect is further reduced cross-talk.
[0033] One or more of the first LED filament and the second filament, and where provided the third filament may be obliquely arranged with respect to the longitudinal direction of the LED filament lamp. The first LED filament and the second filament, and where provided the third filament may be arranged in an angle relative to the longitudinal direction of the LED filament lamp. The first LED filament and the second filament, and where provided the third filament may each be arranged in different angles relative to the longitudinal direction of the LED filament lamp.
[0034] In an embodiment said LED filament lamp comprises a light transmissive envelope at least partly enclosing the first LED filament, the second LED filament and, where provided, the third LED filament, wherein the envelope and the respective LED filaments are arranged in electrically connection with at least one lamp connector configured for mechanically and electrically connecting said LED filament lamp to a socket of a luminaire.
[0035] LED lamp comprises a light transmissive envelope at least partly enclosing the first LED filament, the second LED filament and, where provided, the third LED filament. The envelope may be arranged in contact with at least one connector configured for mechanically connecting the LED filament lamp to a socket of a luminaire. The respective LED filaments are arranged in contact with at least one connector configured for mechanically and electrically connecting said LED filament lamp to a socket of a luminaire. The LED filament lamp may comprise a base member. The base member may be the connector. The envelope and the respective LED filaments are arranged in contact with a base member for connecting the LED filament lamp to a socket of a luminaire.
[0036] In an embodiment the LED filament lamp comprises at least two first LED filaments and at least two second LED filaments.
[0037] LED filament lamp comprises at least two first LED filaments and at least two second LED filaments. LED filament lamp may also comprise at least two third LED filaments. The LED filament lamp may alternatively comprise at least three first LED filaments and at least three second LED filaments. LED filament lamp may also comprise at least three third LED filaments. The at least two first LED filament and the at least two second LED filament, and where present the at least two third filament are arranged in a distance, D, from one another, wherein D may be at least 7mm. The at least two first LED filament and the at least two second LED filament, and where present the at least two third filament are arranged approximately uniformly distributed in the LED filament lamp.
[0038] In an embodiment a cross-sectional shape of the envelope is circular, wherein the at least two first LED filaments and the at least two second LED filaments are arranged alternatingly and equally distributed around a center axis of the envelope.
[0039] The cross-sectional shape of the envelope may be circular. The at least two first LED filaments and the at least two second LED filaments may be arranged alternatingly and equally distributed around a center axis of the envelope. The at least two first LED filaments and the at least two second LED filaments, and when provided the at least two third LED filaments may be arranged alternatingly and equally distributed around a center axis of the envelope.
[0040] In an embodiment the first LED filament and the second LED filament are arranged in the LED filament lamp, such that the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face each other, or the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face an inner surface of the envelope, or the respective second major surface or the respective fourth major surface of the first LED filament and the second LED filament face an inner surface of the envelope.
[0041] The first LED filament and the second LED filament may be arranged in the LED filament lamp, such that the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face each other. Alternatively, the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face an inner surface of the envelope. Alternatively, the respective second major surface or the respective fourth major surface of the first LED filament and the second LED filament face an inner surface of the envelope. The second blue LEDs configured to, in operation, emit second LED light being blue light, may be facing away from the center axis of the envelope. The center axis of the envelope may be similar to the longitudinal axis of the LED filament lamp. The center axis of the envelope may be parallel to the longitudinal axis of the LED filament lamp.
[0042] In an embodiment each of the first LED filament, the second LED filament, and where provided the third LED filament, comprises a longitudinal axis, and wherein the first LED filament, the second LED filament, and where provided the third LED filament are arranged such that the respective longitudinal axes of at least the first LED filament and the second LED filament extend in different planes.
[0043] The first LED filament has a first longitudinal axis, wherein the first longitudinal axis may extend in a first plane. The first longitudinal axis may be arranged in a parallel or angled position relative to the longitudinal axis of the LED filament lamp. The second LED filament has a second longitudinal axis, wherein the second longitudinal axis may extend in a second plane. The second longitudinal axis may be arranged in a parallel or angled position relative to the longitudinal axis of the LED filament lamp. The second longitudinal axis may be arranged in a parallel or angled position relative to the first longitudinal axis. Where the third LED filament is provided, the third LED filament comprises a third longitudinal axis extending in a third plane. The third longitudinal axis may be arranged in a parallel or angled position relative to the longitudinal axis of the LED filament lamp. The third longitudinal axis may be arranged in a parallel or angled position relative to the respective first and second longitudinal axes. The first LED filament, the second LED filament, and where provided the third LED filament may be arranged, such that the respective longitudinal axes of at least the first LED filament, the second LED filament and the third filament extend in the same plane or in different planes.
[0044] In an embodiment the LED filament lamp further comprises a controller configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately, such that said controller individually controls the first LED light emitted by said plurality of first blue LEDs, the second LED light emitted by said plurality of second blue LEDs and the third LED light emitted by said plurality of red LEDs, and the controller is configured control said first LED filament and second LED filament, such that the lamp light in a first operational mode is only first LED light, in a second operational mode is only second LED light, in a third operational mode is only third LED light, and in a fourth operational mode is white lamp light having a correlated color temperature in a range from 1700K to 6500K and a color rendering index of at least 80.
[0045] The LED filament lamp may be controlled by using an internal or external controller. The internal controller may be arranged inside the LED filament, for example in the base. The external controller may control the internal controller wireless or wired. The controller may be configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately. The controller individually controls the intensity of the LED light emitted by the plurality of LEDs, when controlling the LEDs electrically. The controller individually controls the intensity of the first LED light emitted by said plurality of first blue LEDs, and the intensity of the second LED light emitted by said plurality of second blue LEDs and the intensity of third LED light emitted by said plurality of red LEDs.
[0046] The controller may control the first LED filament and second LED filament, such that the lamp light emitting from the LED filament lamp in a first operational mode may only be first LED light. By the term “only”, it should be understood that at least 95% of the lamp light may be first LED light in the first operational mode. Preferably 98% of the lamp light may be first LED light. More preferably 99% of the lamp light may be first LED light. Most preferably 100% of the lamp light may be first LED light.
[0047] In a second operational mode the lamp light emitting from the LED filament lamp may only be second LED light. By the term “only”, it should be understood that at least 95% of the lamp light may be second LED light in the second operational mode. Preferably 98% of the lamp light may be second LED light. More preferably 99% of the lamp light may be second LED light. Most preferably 100% of the lamp light may be second LED light.
[0048] In a third operational mode the lamp light emitting from the LED filament lamp may only be third LED light. By the term “only”, it should be understood that at least 95% of the lamp light may be third LED light in the third operational mode. Preferably 98% of the lamp light may be third LED light. More preferably 99% of the lamp light may be third LED light. Most preferably 100% of the lamp light may be third LED light.
[0049] In a fourth operational mode the lamp light emitting from the LED filament lamp may be a white lamp light having a correlated color temperature in a range from 1700K to 6500K and a color rendering index of the white lamp light is at least 80. Preferably the color rendering index of the white lamp light is at least 85. More preferably the white lamp light is at least 90. Most preferably the white lamp light is more than 95.
[0050] In an embodiment the controller is configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately such that the lamp light emitted by the LED filament lamp is varied from a first white lamp light having a first correlated color temperature, CCT1, to a second white lamp light having a second correlated color temperature, CCT2, wherein the difference between the first correlated color temperature and the second correlated color temperature is CCT2- CCT1 > 1000 K.
[0051] The controller may furthermore be configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately such that the lamp light emitted by the LED filament lamp is varied between: a white light having a color temperature in a range from 1800 to 6500K, or a first light comprises a first dominant peak wavelength in a blue wavelength range from 430nm to 495nm, or a second light comprises a second dominant peak wavelength in a green / yellow wavelength range from 500nm to 595nm, or a third light comprises a third dominant peak wavelength in a red wavelength range from 600nm to 695nm, or such that the light emitted by the LED filament lamp is varied within the steps of: the white light having a color temperature in the range from 1800 to 3000K, or the white light having a color temperature in the range from 3500 to 4500K, or the white light having a color temperature in the range from 5000 to 6500K. The controller may be configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately, such that the lamp light emitted by the LED filament lamp may be varied.
[0052] The lamp light emitted from the LED filament lamp may be a white lamp light having a color temperature in a range from 1700 to 6500K. Preferably, the lamp light emitted by the LED filament lamp may be varied within the steps of white light having a color temperature in the range from 1800 to 3000K, white light having a color temperature in the range from 3500 to 4500K, or white light having a color temperature in the range from 5000 to 6500K. The lamp light emitted from the LED filament lamp may be a white lamp light having a color temperature in a range from 1800 to 6500K. The white light may comprise a first light having a first dominant peak wavelength in a blue wavelength range from 430nm to 495nm. The white light may also comprise second light comprises a second dominant peak wavelength in a green / yellow wavelength range from 500nm to 595nm, and when present. The white light may also comprise a third light comprises a third dominant peak wavelength in a red wavelength range from 600nm to 695nm.
[0053] The lamp light emitted from the LED filament lamp may also vary between a first light comprises a first dominant peak wavelength in a blue wavelength range from 430nm to 495nm, or a second light comprises a second dominant peak wavelength in a green / yellow wavelength range from 500nm to 595nm, or a third light comprises a third dominant peak wavelength in a red wavelength range from 600nm to 695nm.
[0054] The LED filaments may be controllable, such that the LED filament together emits white light with a color temperature in the range 1800 - 3000 K, preferable in the range 2000 - 2700 K, more preferably in the range 2100 - 2400 K, and most preferably in the range 2150-2350 K.
[0055] The LED filaments may also be controllable, such that the LED filament together emits white light with a color temperature in the range 3500 - 5000 K, preferable in the range 3500 - 4500 K, more preferably in the range 3700 - 4300 K, and most preferably in the range 3800-4200 K. The LED filaments may furthermore be controllable, such that the LED filament together emits white light with a color temperature in the range 5000 - 7000 K, preferable in the range 5500 - 6500 K, more preferably in the range 5700 - 6300 K, and most preferably in the range 5800-6200 K. By controlling the relative intensity of each type of LED, the color temperature of the emitted light can be controlled. The lamp light may be controlled such that the color temperature is varied stepless or by step of 500 K. The lamp light may be controlled such that the color temperature is preferably varied by step of 250 K.
[0056] The lamp light may be controlled such that the color temperature is more preferably varied by step of 100 K. The lamp light may be controlled such that the color temperature is most preferably varied by step of 50 K. The white light may be varied substantially along a blackbody locus or along a line perpendicular to the blackbody locus following a predetermined color temperature.
[0057] It is noted that the invention relates to all possible combinations of features recited in the claims.
[0058] BRIEF DESCRIPTION OF THE DRAWINGS
[0059] 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.
[0060] Fig. 1 illustrates a schematic side view of a LED filament lamp.
[0061] Figs. 2a and 2b illustrate schematic side views of LED filaments.
[0062] Figs. 3a and 3b illustrate schematic cross sectional views of positions of LED filaments in a LED filament lamp.
[0063] Fig. 4 illustrates different variations of light emitting from five LED filaments.
[0064] Fig. 5 illustrates a schematic side view of a first, a second and a third LED filament.
[0065] Figs. 6a and 6b illustrate schematic side views of a first and a second LED filament.
[0066] As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.
[0067] DETAILED DESCRIPTION
[0068] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.
[0069] Fig. 1 illustrates a schematic side view of a LED filament lamp 1. The LED filament lamp 1 comprise an envelope 4 and a base 5. LED filament lamp 1 comprises a first LED filament 2 and a second LED filament 3. LED filament lamp 1 may comprise a light transmissive envelope 4 enclosing the first LED filament 2 and the second LED filament 3. The envelope 4 and the respective LED filaments 2, 3 are arranged in contact with the base 5. The first LED filament 2 and the second LED filament 3 are mechanically and electrically connected to the base 5. The base 5 is configured such that the LED filament lamp 1 may be connected to a socket of a luminaire. The envelope 4 comprises a center axis. The center axis of the envelope 4 is parallel to the longitudinal axis Xi of the LED filament lamp 1. The shape of the LED filament lamp 1 illustrated in fig. 1 may be referred to as a classic filament LED bulb or a retrofit light bulb. LED filament lamp 1 comprises at least one first LED filament 2, such as a phosphor-converted green LED filament, and a second LED filament 3, such as a direct-emitting dual-color LED filament. The LED filaments 2 and 3 may be arranged parallel to each other, extending along the longitudinal axis Xi of the LED filament lamp 1.
[0070] The first LED filament 2 and the second LED filament 3 are arranged in a distance, D, from each other inside the LED filament lamp 1. The distance, D, between the LED filaments 2, 3 may depend on the size and shape of the LED filament lamp 1. The distance, D, between the LED filaments 2, 3 may depend on the size and shape of the LED filament 2, 3, which is arranged inside the LED filament lamp 1. The distance, D, between the LED filaments 2, 3 may depend on the numbers of first and second filament 2, 3, which may be placed inside the LED filament lamp 1. The LED filament lamp 1 further comprises a controller 6. The controller 6 is configured to individually control each respective array of LEDs of each respective LED filaments 2, 3 of the LED filament lamp 1 separately.
[0071] Figs. 2a and 2b illustrate two different schematic side views of LED filaments. Fig. 2a illustrate a LED filament comprising an elongated carrier 7 having a first major surface l l1and a second major surface 112. In this example LEDs 91, 9n, 10 is arranged on the first major surface 111. The elongated carrier 7 has a longitudinal direction (arrow on Fig. 2a) defining a longitudinal axis X2. The elongated carrier 7 may be translucent. The elongated carrier 7 or carriers may be reflective or light transmissive, such as translucent and preferably transparent. The elongated carrier 7 is covered by an elongated encapsulant 8. The elongated encapsulant 8 comprises a luminescent material. The luminescent material is configured to convert light into a converted light, which substantially is a converted green light. For example, the luminescent material comprises a phosphor-converting material, such that the light emitting from the LEDs is converted into a green light. Alternatively, the LED filament 2, 3 may comprise a carrier 7 covered by an encapsulant 8 comprising a light scattering material. The light scattering material is configured to scatter the LED light into scattered light.
[0072] Referring also to Fig. 2b, the first LED filament 2 comprises a plurality of LEDs configured to, in operation, emit LED light as a greenish converted light. The second LED filament 3 comprises a plurality of LEDs 91, 10 configured to, in operation, emit LED light as a colored light, which is blue or red light. Alternatively, the second LED filament 3 is configured to, in operation, emit a third LED light being for example a second blue and first red light. The light emitting from the LED filament lamp 1 may be controlled as a tunable light capable of alter the light between different color temperature during use. The controller 6 may control each respective array of LEDs of each respective LED filament of the LED filament lamp separately, such that the lamp light emitted by the LED filament lamp may be varied. The LED filament lamp 1 may emit white light which provides a color temperature in the range from 1800 to 3000K. The LED filament lamp 1 may also be capable of emitting white light which provide a color temperature in the range from 3500 to 4500K. The LED filament lamp 1 may further be capable of emitting white light which provides a color temperature in the range from 5000 to 6500K.
[0073] Figs. 3a and 3b illustrate two different schematic cross sectional views of possible positions of LED filaments in a LED filament lamp 1 according to the invention. The LED filament lamp 1 comprises a plurality of first LED filaments 2 and a plurality of second LED filaments 3 alternately arranged along the circumference of the envelope of the LED filament lamp 1. In the embodiment shown in Fig. 3a, the LED filament lamp 1 comprises three first LED filaments 2 and three second LED filaments alternately arranged along the circumference of the envelope of the LED filament lamp 1. In the embodiment shown in Fig. 3b the LED filament lamp 1 comprises two first LED filaments 2 and two second LED filaments alternately arranged along the circumference of the envelope of the LED filament lamp 1. The first and second filaments 2, 3 are spaced equally apart by a distance D from one another, when arranged inside the LED filament lamp 1. The distance D between the respective LED filaments 2, 3 depends on the size and shape of the LED filament lamp 1. The distance D between the LED filaments 2, 3 may depend on the size and shape of the LED filament 2, 3 which is arranged inside the LED filament lamp 1. The distance D between the LED filaments may depend on the numbers of first and second filament 2, 3, which is placed inside the LED filament lamp 1.
[0074] Fig. 4 illustrates five different variations of light emitting from five LED filaments. A first variation of light 121emitting from the LED filament lamps 1 may be a greenish light provided by the first LED filament 2. A second variation of LED light 122emitting from the LED filament lamps 1 may be a warm white light provided by the first and second LED filament 2, 3 together. A third variation of light 123emitting from the LED filament lamps 1 may be a cool white light provided by the first and second LED filament 2, 3 together. A fourth variation of light 124emitting from the LED filament lamps 1 may be a red light provided by the second LED filament 3. A fifth variation of light 125emitting from the LED filament lamps 1 may be a blue light also provided by the second LED filament 3.
[0075] Fig. 5 illustrates a schematic side view of a first LED filament 2, a second LED filament 3 and a third LED filament 13. The LED filament lamp 1 may thus further comprise a third LED filament 13. The third LED filament 13 may comprise a plurality of fourth blue LEDs configured to, in operation, emit fifth LED light being third blue light. The plurality of fourth blue LEDs may be covered by a third encapsulant comprising a third luminescent material configured to convert the third blue light at least partially into a third converted light. The third converted light may be a green light, red light, or a combination of green light and red light. The LED filament lamp 1 may comprise a first LED filament 2, a second LED filament 3 and, where provided, a third LED filament 13. The LED filament lamp 1 may be configured to provide lamp light emitting from a combination of a plurality of LED filaments emitting a plurality of wavelength ranges. The respective LED filaments are arranged in contact with at least one connector configured for mechanically and electrically connecting said LED filament lamp to a socket of a luminaire.
[0076] Figs. 6a and 6b illustrate a schematic side view of two different embodiments of a first and a second LED filament 2, 3. The first LED filament 2 comprises a first elongated carrier, as shown in Fig. 2a, having a first major surface l l1and a second major surface 112arranged opposite each other. The first major surface 111and the second major surface 112are adapted to receive a plurality of first blue LEDs 91. The first blue LEDs 91emit first LED light being blue light. The first blue LEDs 91may be configured to emit first blue light having a dominant peak wavelength in a wavelength range from 400 nm to 480 nm. The plurality of first blue LEDs 91is covered by a first encapsulant 81comprising a first luminescent material. The first luminescent material converts the first LED light into a first converted light when passing through the first encapsulant 81. The first converted light being green light having a dominant peak wavelength in a wavelength range from 510 nm to 580 nm.
[0077] The second LED filament 3 has a second carrier 7, which comprises a third major surface and a fourth major surface arranged opposite each other. The second carrier 7 comprises a third major surface configured to receive LEDs 10 and a fourth major surface configured to receive LEDs 92. The plurality of second blue LEDs 92and the plurality of red LEDs 10 are arranged in at least one second array on the second carrier 7. The plurality of second blue LEDs 92emit a second LED light being blue light. The second blue LEDs 92may emit second blue light blue light having a dominant peak wavelength in a wavelength range from 400 nm to 480 nm. The plurality of red LEDs 10 emits third LED light being red light. The red LEDs may be configured to emit third LED light emitted having a dominant peak wavelength in a wavelength range from 600 nm to 680 nm. The light, which emits from the second LED filament may be blue light or red light, or a light mixed with blue light or red light.
[0078] Fig. 6a shows in the left-hand side a first example, wherein the second LED filament 3 having the plurality of second blue LEDs 91and the plurality of red LEDs 10 are arranged altematingly on the third major surface. The plurality of second blue LEDs 91and the plurality of red LEDs 10 are arranged altematingly on the third major surface and if present on the fourth major surface of the second elongated carrier 7. A second example is shown in the right-hand side of Fig. 6a, wherein second LED filament 3 having the plurality of second blue LEDs 91is arranged on side of the second carrier 7, the third major surface. The plurality of red LEDs 10 is arranged on the opposite side of the second carrier 7, the fourth major surface.
[0079] Fig. 6b shows a first example, wherein the first LED filament 2 comprises two encapsulants, 81, 82having a first and a second luminescent material 8', 8" different from each other. The second LED filament may comprise the plurality of second blue LEDs 91, and the plurality of red LEDs 10 are arranged relative to each other as described in connection with Fig. 6a. The plurality of first blue LEDs 91is arranged on the first major surface on the first elongated carrier. The first LED filament 2 further comprises a plurality of third blue LEDs 93. The third blue LEDs 93may emit a fourth LED light. The third blue LEDs 93may emit a first light similar to the first blue LEDs 91. The plurality of third blue LEDs 93is arranged on said second major surface of the first carrier. The plurality of third blue LEDs 93may be covered by a second elongated encapsulant 82. The second elongated encapsulant 82may be different from the second elongated encapsulant 81. The second elongated encapsulant 82may comprise a second luminescent material 8". The second luminescent material 8" may be different that the first luminescent material 8'. The second luminescent material 8" may convert the fourth LED light into a second converted light. The second converted light may be green light having a peak emission wavelength higher than a peak emission wavelength of the first converted light.
[0080] 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.
[0081] Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.
Claims
CLAIMS:
1. A LED filament lamp (1) providing lamp light, wherein the LED filament lamp (1) comprises: at least one first LED filament (2) emitting first LED filament light and comprises a first elongated carrier having a first major surface and a second major surface arranged opposite each other, wherein the first major surface is adapted to receive a plurality of first blue LEDs (91) configured to, in operation, emit first LED light being first blue light, wherein said first blue LEDs (91) are arranged in at least one first array on said first elongated carrier (71), wherein the plurality of first blue LEDs (91) is covered by a first elongated encapsulant (81) comprising a first luminescent material (8') configured to fully convert the first LED light into a first converted light, the first converted light being a first green light, such that the first LED filament (2) emits first green light; at least one second LED filament (3) emitting second LED filament light and comprises a second elongated carrier (72) having a third major surface and a fourth major surface arranged opposite each other, wherein the third major surface and the fourth major surface are adapted to receive:(i) a plurality of second blue LEDs (92) configured to, in operation, emit second LED light being second blue light, and(ii) a plurality of red LEDs (10) configured to, in operation, emit third LED light being first red light, wherein the plurality of second blue LEDs (92) and the plurality of red LEDs (10) are arranged in at least one second array on said second elongated carrier (72), such that the second LED filament (3) emits second blue light and first red light.
2. LED filament lamp (l)according to claim 1, wherein the at least one first LED filament (2) and the at least one second LED filament (3) are arranged at a distance, D, from one another, wherein D is at least 5mm.
3. LED filament lamp (1) according to claim 1 or 2, wherein the first LED filament (2) further comprises a plurality of third blue LEDs (93) configured to, in operation,emit a fourth LED light being a third blue light, wherein the plurality of third blue LEDs (93) is arranged on said second major surface (112) of the first elongated carrier (71), wherein the plurality of third blue LEDs (93) is covered by a second elongated encapsulant (82) comprising a second luminescent material (8") configured to fully convert the fourth LED light into a second converted light, and wherein the second converted light is a second green light having a peak emission wavelength higher than a peak emission wavelength of the first converted light.
4. LED filament lamp (1) according to claim 1 or 2, and further comprising a third LED filament (13) configured to emit a third LED filament light, wherein the third LED filament (13) comprises a plurality of fourth blue LEDs (94) configured to, in operation, emit fifth LED light being third blue light, wherein the plurality of fourth blue LEDs (94) is arranged in at least one array on the third elongated carrier (73), wherein the plurality of fourth blue LEDs (94) is covered by a third encapsulant (83) comprising a third luminescent material configured to at least partially convert the fifth blue light into a third converted light, and wherein the third converted light is third green light, second red light or a combination of green light and red light.
5. LED filament lamp (1) according to any of the preceding claims, wherein: the plurality of second blue LEDs (92) and the plurality of red LEDs (10) are arranged altematingly on said third major surface (113) of the second elongated carrier (3), or the plurality of second blue LEDs (92) and the plurality of red LEDs (10) are arranged altematingly on said third major surface (113) and on said fourth major surface (114) of the second elongated carrier (3), wherein the fourth major surface is opposite to the first major surface, or the plurality of second blue LEDs (92) is arranged on said third major surface (113) of the second elongated carrier (3) and the plurality of red LEDs (10) are arranged on said fourth major surface (114) of the second elongated carrier (3).
6. LED filament lamp (1) according to any of the preceding claims, wherein the second LED filament (3) comprises a third encapsulant (83) comprising a light scattering material configured to scatter the second LED light into second scattered light and the third LED light into third scattered light, wherein said third encapsulant (83) covers said plurality of second blue LEDs (92) and said plurality of red LEDs (10).
7. LED filament lamp (1) according to any one of the preceding claims, wherein the one or more of the first elongated carrier (71), the second elongated carrier (72) and, where provided, the third elongated carrier (73) is translucent, and said respective elongated carriers are configured to at least partly transmit a LED light, which LED light comprises one or both of a direct light and a converted light.
8. LED filament lamp (1) according to any one of the preceding claims, wherein the first LED filament (2) is obliquely arranged with respect to the second LED filament (3), and wherein an axis of elongation (LI) of the first LED filament (2) and an axis of elongation (L2) of the second LED filament (3) are not arranged in a plane; and where provided, wherein the third LED filament (12) is obliquely arranged with respect to the second LED filament (3), and wherein an axis of elongation (L3) of the third LED filament (12) and an axis of elongation (L2) of the second LED filament (3) are not arranged in a plane.
9. LED filament lamp (1) according to any of the preceding claims, wherein said LED filament lamp comprises a light transmissive envelope (4) at least partly enclosing the first LED filament (2), the second LED filament (3) and, where provided, the third LED filament (13), wherein the envelope (4) and the respective LED filaments (2, 3,13) are arranged in electrically connection with at least one lamp connector configured for mechanically and electrically connecting to said LED filament lamp to a socket of a luminaire.
10. LED filament lamp (1) according to any one of the preceding claims, wherein the LED filament lamp comprises at least two first LED filaments (2) and at least two second LED filaments (3).
11. LED filament lamp (1) according to claim 10, wherein a cross-sectional shape of the envelope is circular, wherein the at least two first LED filaments and the at least two second LED filaments are arranged alternatingly and equally distributed around a center axis of the envelope (4).
12. LED filament lamp (1) according to any one of the preceding claims, wherein:the first LED filament and the second LED filament are arranged in the LED filament lamp, such that the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face each other, or the respective first major surface or the respective third major surface of the first LED filament and the second LED filament face an inner surface of the envelope, or the respective second major surface or the respective fourth major surface of the first LED filament and the second LED filament face away from a longitudinal axis of the LED filament lamp.
13. LED filament lamp (1) according to any one of the preceding claims, wherein each of the first LED filament (2), the second LED filament (3), and where provided the third LED filament (12), comprises a longitudinal axis, and wherein the first LED filament (2), the second LED filament (3), and where provided the third LED filament (12) are arranged such that the respective longitudinal axes of at least the first LED filament (2) and the second LED filament (3) extend in different planes.
14. LED filament lamp (1) according to any of the preceding claims, wherein the LED filament lamp (1) further comprises a controller (6) configured to individually control each respective array of LEDs of each respective LED filament of the LED filament lamp separately, such that said controller (6) individually controls the first LED light emitted by said plurality of first blue LEDs (91), the second LED light emitted by said plurality of second blue LEDs (92) and the third LED light emitted by said plurality of red LEDs (10); and wherein the controller is configured control said first LED filament (2) and second LED filament (3), such that the lamp light in a first operational mode is only first LED light, in a second operational mode is only second LED light, in a third operational mode is only third LED light, and in a fourth operational mode is white lamp light having a correlated color temperature in a range from 1700K to 6500K and a color rendering index of at least 80.
15. LED filament lamp (1) according to claim 14, wherein the controller (6) is configured to individually control each respective array of LEDs of each respective LED filament (2, 3,12) of the LED filament lamp (1) separately, such that the lamp light emitted by the LED filament lamp (1) is varied from a first white lamp light having a first correlatedcolor temperature (CCT1) to a second white lamp light having a second correlated color temperature (CCT2), wherein the difference between the first correlated color temperature and the second correlated color temperature is equal to or more than 1000 K.