Color temperature controllable LED filament lamp providing improved light quality

Abstract

A lighting device (320) comprising at least one first light emitting diode, LED, filament (100) adapted to emit light having a first correlated color temperature, CCT, and at least one second LED filament (200) adapted to emit light having a second, different, CCT. Each LED filament is arranged to emit a first, larger, portion of light (112) from a first side (105) and a second, smaller, portion of light (114) from a second side (107). A longitudinal axis (A) extends from a base (322) of the lighting device to a top (330) of the envelope. Each of the at least one first LED filament is arranged at a first angle (a1) to the longitudinal axis, with a first surface facing generally towards the top of the lighting device, and each of the at least one second LED filament is arranged at a second angle (a2) to the longitudinal axis, with a first surface facing generally towards the base.

Description

Technical Field

[0001] This disclosure generally relates to the field of solid-state lighting. More specifically, this disclosure relates to lighting devices including light-emitting diode filaments providing different color temperatures. Background Technology

[0002] Incandescent bulbs are being rapidly replaced by LED-based lighting solutions. Nevertheless, users still welcome and expect modified lamps that retain the appearance of incandescent bulbs.

[0003] Solid-state lighting devices offer many advantages over their incandescent, fluorescent, and gas discharge-based counterparts. For example, they can provide increased lifespan, reduced power consumption, and higher efficiency. Solid-state lighting devices, such as LEDs, are used in a wide range of lighting applications.

[0004] The development of LED-based lighting devices is ongoing and can provide new solutions that extend far beyond what is possible with traditional light sources.

[0005] WO 2019 / 166273 discloses an LED filament lamp comprising a light-emitting diode (LED) light source having at least one first filament and at least one second filament, the at least one first filament being arranged to emit light having a first color temperature, and the at least one second filament being arranged to emit light having a second color temperature different from the first color temperature, wherein each of the first and second filaments includes an elongated substrate, and wherein at least one LED is disposed on the substrate. The LED filament lamp also includes a control unit configured to control a first intensity of light emitted from(a plurality of) the first filament(s) and a second intensity of light emitted from(a plurality of) the second filament(s) according to at least one predetermined setting, so as to control the total color temperature of the light emitted from the LED filament lamp according to(a plurality of) predetermined settings. Summary of the Invention

[0006] A general objective of this disclosure is to provide a lighting device that provides light with different color temperatures in different directions. Furthermore, this lighting device can provide light from different directions.

[0007] This and other objectives are achieved by means of the lighting device defined in the appended independent claims. Other embodiments are defined by the dependent claims.

[0008] According to a first aspect of this disclosure, a lighting device is provided. The lighting device includes at least one first light-emitting diode (LED) filament adapted to emit light having a first correlated color temperature (CCT). The lighting device also includes at least one second LED filament adapted to emit light having a second CCT different from the first CCT. Each LED filament (i.e., each of the plurality of first LED filaments and each of the plurality of second LED filaments) has a first side and a second side arranged opposite to each other and extending along the elongation direction of the LED filament. Furthermore, each LED filament (i.e., each first LED filament and each second LED filament) is arranged to emit (or output) a first larger portion of light from its first side and to emit (or output) a second smaller portion of light from its second side.

[0009] The lighting device also includes a base that can be connected to a luminaire socket and a housing that is at least partially transparent. The housing at least partially encloses at least one first LED filament and at least one second LED filament. The housing is mounted on the base.

[0010] The longitudinal axis extends from the base to the top of the casing (the top is opposite the base along the longitudinal axis).

[0011] Each LED filament in at least one first LED filament is arranged at a first angle relative to the longitudinal axis. Each LED filament in at least one first LED filament is further arranged (rotated / angled) such that its first side generally faces the top of the lighting device. The second side of each LED filament in at least one first LED filament therefore generally faces the base of the lighting device. The first angle can be defined as the angle formed from the first LED filament to the longitudinal axis.

[0012] Each LED filament in at least one second LED filament is arranged at a second angle relative to the longitudinal axis. Each LED filament in at least one second LED filament is further arranged (rotated / angled) such that its first side generally faces the base of the lighting device. The second side of each LED filament in at least one second LED filament therefore generally faces the top of the lighting device. The second angle can be defined as the angle formed from the second LED filament to the longitudinal axis.

[0013] The whiteness of a light source is typically described in relation to an ideal blackbody radiator. As the temperature of an ideal blackbody increases, it begins to emit light. At relatively low temperatures, it emits red light. As the temperature rises further, the emitted light becomes yellowish, and finally, at very high temperatures, the emitted light becomes white. The correlated color temperature (CCT) of a light source is the temperature (expressed in Kelvin) of an ideal blackbody radiator that displays the most similar colors. The blackbody line or blackbody trajectory (BBL) is the path that such a blackbody will take in a specific color space as its temperature varies. In other words, the BBL encompasses or describes the different colors that an ideal blackbody will emit at different temperatures.

[0014] In a sense, the everyday concept of color temperature is the opposite of the CCT scale. Typically, redder light is described as warmer, while white-blue light is described as cooler. In the CCT scale, red (warm) light corresponds to a lower (cooler) temperature, while white-blue (cool) light corresponds to a higher (warmer) temperature.

[0015] Each of the at least one first LED filaments can emit (or output) a significant portion of its light from its first side. Since each of the at least one first LED filaments is arranged at an angle to the longitudinal axis, such that the first side of the LED filament generally faces the top of the lighting device, a significant amount (or a portion) of the light with the first CCT can be emitted (or output) from the top of the lighting device rather than from the bottom of the lighting device.

[0016] Similarly, each of the at least one second LED filaments can emit (or output) a larger portion of its light from its first side. Since each of the at least one second LED filaments is arranged at an angle to the longitudinal axis, such that the first side of the LED filament generally faces the base of the lighting device, a larger portion (or a portion) of the light having the second CCT can be emitted (or output) from the base of the lighting device rather than from the top of the lighting device. Therefore, the lighting device described in this disclosure can provide light with one color temperature (light having a larger portion with the first CCT and a smaller portion with the second CCT) from the top of the lighting device and light with another color temperature (light having a smaller portion with the first CCT and a larger portion with the second CCT) near the base of the lighting device.

[0017] Therefore, a single lighting device can provide light with different color temperatures in different directions, thus providing a single lighting device for different lighting purposes. The lighting device can also be used to provide light in different directions. For example, light with a first color temperature can exit from the top of the lighting device (or the luminaire in which the lighting device is arranged), thereby providing, for example, light of the first color temperature as directional light, and light with a second color temperature can be output from the lower part (or base) of the lighting device (or the luminaire in which the lighting device is arranged), thereby providing light of the second color temperature as ambient light (this light is, for example, scattered by the luminaire).

[0018] According to some embodiments, the first angle can be in the range of 20° to 70°. The second angle can be in the range of 20° to 70°.

[0019] Arranging LED filaments at this angle provides a smooth transition between the color temperature of light emitted near the top of the lighting fixture and the color temperature of light emitted near the base of the fixture. This angle also provides a balance between more significant differences in the CCT of light emitted in different directions (which can be the effect of a larger angle) and more omnidirectional illumination (which can be the effect of a smaller angle).

[0020] For example, the first angle can be in the range of 25° to 65°. Specifically, the first angle can be in the range of 30° to 60°. More specifically, the first angle can be in the range of 35° to 55°.

[0021] For example, the second angle can be in the range of 25° to 65°. Specifically, the second angle can be in the range of 30° to 60°. More specifically, the second angle can be in the range of 35° to 55°.

[0022] According to some embodiments, the first angle may be at least substantially equal to the second angle.

[0023] Arranging at least one first LED filament and at least one second LED filament at the same (or at least substantially the same) angle to the longitudinal axis can facilitate the production of such a lighting device. It also provides a pleasing appearance. According to some embodiments, the difference between the first CCT and the second CCT can be at least 500K.

[0024] A difference of at least 500K in CCT can provide a significant difference in the light delivered in relative directions (i.e., near the top of the lighting fixture and near the base of the lighting fixture).

[0025] For example, the difference between the first CCT and the second CCT can be at least 700K. Specifically, the difference between the first CCT and the second CCT can be at least 900K.

[0026] According to some embodiments, the difference between the first CCT and the second CCT can be less than or substantially equal to 2000K.

[0027] A CCT difference of less than or substantially equal to 2000K can provide more uniform illumination and allow for a smoother transition between lights with different CCTs.

[0028] For example, the difference between the first CCT and the second CCT can be less than or substantially equal to 1700K. Specifically, the difference between the first CCT and the second CCT can be less than or substantially equal to 1600K.

[0029] According to some embodiments, the first CCT may be higher than the second CCT.

[0030] Many luminaires and lighting fixtures are arranged such that the top of the fixture (opposite to its base) points towards an area particularly deserving of illumination. Examples of such luminaires / lighting fixtures are table lamps, work lamps, reading lamps, many pendant lights, etc. Such lighting fixtures can provide directional light toward a surface of interest (such as a table surface) as well as general light in other directions. The lighting fixture according to this embodiment can provide “cooler” directional light toward a surface or area of ​​interest (i.e., directional light with a higher CCT) and “warmer” ambient light with a lower CCT. A higher CCT can improve the visibility of objects and, for example, facilitate reading, while a lower CCT can provide a more pleasant atmosphere.

[0031] According to some embodiments, the first CCT can be higher than or substantially equal to 2700K.

[0032] For example, the first CCT can be higher than or substantially equal to 3000K. Specifically, the first CCT can be higher than or substantially equal to 3500K, such as, for example, 4000K.

[0033] According to some embodiments, the second CCT may be less than or substantially equal to 2500K.

[0034] For example, the second CCT can be less than or substantially equal to 2300K. Specifically, the second CCT can be less than or substantially equal to 2200K, such as, for example, 2000K.

[0035] According to some embodiments, the lighting device can be adapted to emit light with an average CCT in the range of 2700K to 3500K.

[0036] The average CCT of a lighting fixture can be calculated by weighting the CCT of each LED filament with the flux of the LED filaments and averaging the weighted CCTs. Alternatively, the average CCT can be obtained by arranging the LED filaments in an integrating sphere and measuring the CCT obtained from that arrangement.

[0037] For example, the average CCT can be in the range of 2800K to 3300K. Specifically, the average CCT of lighting equipment can be in the range of 2900K to 3100K.

[0038] According to some embodiments, each of the LED filaments in at least one first LED filament and each of the LED filaments in at least one second LED filament can be arranged to emit at least X% of its light from its first side. X can be in the range of 60 to 90.

[0039] Therefore, the light emitted from the second side of such an LED filament can account for up to 1%-X% (e.g., up to 10%-40%) of the total light emitted by the LED filament.

[0040] For example, the percentage (X) of light emitted from the first side can be in the range of 65 to 85. Specifically, the percentage (X) of light emitted from the first side can be in the range of 70 to 80.

[0041] According to some embodiments, the number of at least one first LED filament can be in the range of 2 to 6. Furthermore, the number of at least one second LED filament can be in the range of 2 to 6.

[0042] In other words, according to some embodiments, the lighting device may include 2-6 first LED filaments. The lighting device may also include 2-6 second LED filaments.

[0043] For example, the number of first LED filaments can be in the range of 3 to 5, such as 4. For example, the number of second LED filaments can be in the range of 3 to 5, such as 4.

[0044] According to some embodiments, the lighting device may include at least two first LED filaments, and the number (N) of the first LED filaments in the lighting device may be greater than or equal to the number (M) of the second LED filaments in the lighting device.

[0045] For example, the number of first LED filaments can be at least two times and at most three times that of second LED filaments, i.e., 2M ≤ N ≤ 3M. For example, there can be eight first LED filaments and three second LED filaments, i.e., N = 8 and M = 3.

[0046] According to some embodiments, the lighting device may also include a controller. The controller may be configured to provide a first power supply to at least one first LED filament and a second power supply to at least one second LED filament.

[0047] For example, the controller may be adapted to control the power supply to at least one first LED filament separately and / or differently from the power supply to at least one second LED filament.

[0048] For example, the controller can receive input signals and provide power to at least one first LED filament and at least one second LED filament based on the information provided (or carried) by the input signals.

[0049] In embodiments including more than one first LED filament, the controller may be adapted to control the power supply to the first LED filament individually or as a group. Similarly, in embodiments including more than one second LED filament, the controller may be adapted to control the power supply to the second LED filament individually or as a group.

[0050] According to some embodiments, the controller can be configured to: when the input signal increases from a first input level to a second input level, increase the power supply to at least one second LED filament from a first power level to a second power level, and subsequently increase the power supply to at least one first LED filament from a first power level to a second power level. Alternatively or additionally, the controller can be configured to: when the input signal decreases from a second input level to a first input level, decrease the power supply to the at least one first LED filament from a second power level to a first power level, and subsequently decrease the power supply to the at least one second LED filament from a second power level to a first power level.

[0051] Alternatively, when the input signal increases, the power supply to the first LED filament can be increased first, followed by the power supply to the second LED filament. Similarly, when the input signal decreases, the power supply to the second LED filament can be decreased first, followed by the power supply to the first LED filament.

[0052] Therefore, it should be understood that the controller may additionally or alternatively be configured in the opposite manner such that, for example, when the input signal increases, the power supply to at least one first LED filament is increased first, followed by the power supply to at least one second LED filament.

[0053] The first input level can be the minimum input level, and the second input level can be the maximum level.

[0054] The first power level of at least one first LED filament may be equal to the first power level of at least one second LED filament. However, the first power level of at least one first LED filament may be different from the first power level of at least one second LED filament. Similarly, the second power level of at least one first LED filament may be equal to the second power level of at least one second LED filament. In other embodiments, the second power level of at least one second LED filament may be different from the second power level of at least one second LED filament.

[0055] According to some embodiments, the controller may be further configured to: while increasing the power supply to at least one first LED filament from a first power level to a second power level, simultaneously decrease the power supply to at least one second LED filament. Alternatively or additionally, the controller may be configured to: while decreasing the power supply to at least one first LED filament from a second power level to a first power level, simultaneously increase the power supply to at least one second LED filament.

[0056] Therefore, when the input signal increases, at least one first LED filament illuminates. When the second power level is reached, the light intensity can remain the same, but when the first LED filament(s) dims and the light from at least one second LED filament increases, the CCT of the emitted light can change. This can continue, for example, until the first LED filament(s) are turned off and / or the second LED filament(s) are powered at the second power level.

[0057] It should be noted that other embodiments using all possible combinations of the features described in the above embodiments are conceivable. Therefore, this disclosure also relates to all possible combinations of the features mentioned herein. Attached Figure Description

[0058] Exemplary embodiments will now be described in more detail with reference to the following figures:

[0059] Figure 1 A side view of an LED filament according to some embodiments is shown;

[0060] Figure 1a A top view of an LED filament according to some embodiments is shown;

[0061] Figure 2 A lighting device according to some embodiments is shown;

[0062] Figure 3 An LED filament arrangement according to some embodiments is shown;

[0063] Figure 4 An LED filament arrangement according to some embodiments is shown;

[0064] Figure 5 The relationship between the input values ​​of the controller and the corresponding power supply level is shown according to some embodiments;

[0065] Figure 6 The relationship between the input values ​​of the controller and the corresponding power supply level is shown according to some embodiments.

[0066] As shown in the figures, for illustrative purposes, the dimensions of elements and areas may be exaggerated and are therefore provided to illustrate the general structure of the embodiments. The same reference numerals always refer to the same elements. Detailed Implementation

[0067] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate the presently preferred embodiments. However, the invention may 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 to fully convey the scope of the invention to those skilled in the art.

[0068] refer to Figure 1 and Figure 1a The following describes an LED filament according to some embodiments.

[0069] Figure 1 A side view of the LED filament 100 is shown, and Figure 1a A top view of the same LED filament 100 is shown. The LED filament 100 includes an elongated carrier 102. The carrier has a first (main) surface 104 and an opposing second (main) surface 106. A plurality of LEDs 108 are arranged in a linear array on the first surface 104 of the carrier 102. The LEDs 108 are connected via an electrical connection 116, through which the LEDs 108 can be powered.

[0070] Typically, more than 10 LEDs 108 are provided on an LED filament. For example, more than 15 LEDs 108 can be provided, such as more than 20 LEDs 108.

[0071] Sealant 110 seals the first surface 104 of the LED filament 100 and the LED 108. (As shown) Figure 1 and Figure 1a In the illustrated embodiment, sealant 110 may optionally be disposed on the second surface 106. Sealant 110 may be, for example, a polymer, such as a silicone resin that provides good temperature stability.

[0072] The sealant 110 may include light-scattering particles dispersed within the sealant for scattering light emitted by the LED 108. For example, the light-scattering particles may include one or more of barium sulfate (BaSO4), titanium dioxide (TiO2), and aluminum oxide (Al2O3) particles.

[0073] In addition, one or more wavelength-converting materials (such as luminescent materials) can be dispersed in the sealant. This material can absorb light of a first wavelength and emit light of a different second wavelength. For example, the luminescent material can be a phosphor, such as a green / yellow phosphor (e.g., yttrium aluminum garnet (YAG) or lutetium aluminum garnet (LuAG)) and / or an orange / red phosphor (e.g., KSIF, ECAS).

[0074] The carrier 102 may be at least partially translucent (e.g., transparent), such that some light emitted by the LED 108 can be transmitted through the carrier 102 and emitted from the second surface 116 of the carrier 102. The light transmitted through the carrier can form a portion 114 of the smaller portion of the light emitted from the second side 107 of the LED filament 100. However, the larger portion 112 of the light is emitted from the first side 105 of the LED filament. Therefore, as... Figure 1 As shown by the arrow, this means that for a carrier 102 having an LED arranged on its first main surface 104, a larger portion of the light is emitted from the first surface 104 (and away from the carrier 102) compared to light emitted from the second surface 106. This can result in a larger portion 112 of the light being emitted from the first side 105 of the LED filament 100 compared to light emitted from the second side 107.

[0075] LED 108 may include LEDs suitable for emitting blue and / or UV light. Alternatively or additionally, the LED may include LEDs suitable for emitting different colors of light, such as red, green, and blue (RGB) LEDs. A combination of blue / UV LEDs and red LEDs may also be used.

[0076] Therefore, the light emitted by LED 108 (LED light) can be scattered by particles in the sealant. Some LED light can also be absorbed by the color-converting material and emitted at different wavelengths. Therefore, the color (and CCT) of the light emitted by LED filament 100 can depend on the type (color) of the LED used and the presence (and type) of the wavelength-converting material in the sealant 110.

[0077] The LED filament 100 can emit light in all directions. However, a larger portion 112 of the light is emitted from the first side 105 of the LED filament 100. A smaller portion 114 of the LED light is then emitted from the second side 107 of the LED filament. The larger portion 112 and the smaller portion 114 of the light have (substantially) the same color temperature.

[0078] Typically, an LED filament can provide LED filament light and may comprise multiple light-emitting diodes (LEDs) arranged in a linear array. Preferably, the LED filament has a length L and a width W, where L > 5W. The LED filament can be arranged in a straight configuration or a non-straight configuration, such as, for example, a curved configuration, a 2D / 3D spiral, or a helix. Preferably, the LEDs are arranged on an elongated carrier, such as a substrate, which can be rigid (e.g., made of polymer, glass, quartz, metal, or sapphire) or flexible (e.g., made of polymer or metal (e.g., film or foil)).

[0079] In the case where the carrier comprises a first main surface and an opposing second main surface, the LED is disposed on at least one of these surfaces. The carrier can be reflective or translucent, such as translucent and preferably transparent.

[0080] LED filaments may include a sealant that at least partially covers at least a portion of a plurality of LEDs. The sealant may also at least partially cover at least one of a first or second main surface. The sealant may be a flexible polymeric material (such as silicone). Furthermore, the LEDs may be arranged to emit LED light of, for example, different colors or spectra. The sealant may include a luminescent material configured to at least partially convert the LED light into converted light. The luminescent material may be a phosphor (such as an inorganic phosphor and / or quantum dots or quantum rods).

[0081] LED filaments can include multiple sub-filaments.

[0082] refer to Figure 2 This document will describe a lighting device according to some embodiments.

[0083] Figure 2 This is a schematic diagram of a lighting device 320 according to some embodiments. The lighting device 320 includes a first LED filament 100 and a second LED filament 200. The first and second LED filaments 100 and 200 are equivalent to those previously referenced. Figure 1 and Figure 1a The LED filament is described. The first LED filament 100 is adapted to emit light having a first CCT, and the second LED filament 200 is adapted to emit light having a second CCT different from the first CCT.

[0084] The lighting device 320 also includes a housing 324 that is at least partially transparent. The housing 324 encapsulates LED filaments 100 and 200. The housing 324 is mounted on a base 322, which is adapted to be connected to a socket of the luminaire.

[0085] LED filaments 100 and 200 are connected to the base via a retaining device 328, which also holds the LED filaments 100 and 200 in position within the housing 324. Optionally, the lighting device may also include a controller 326 adapted to supply power to the first LED filament 100 and the second LED filament 200. The retaining device 328 may also include electrical connections connecting the LED filaments 100 and 200 to the controller 326 and / or the base 322.

[0086] The longitudinal axis A extends from the base 322 to the top 330 of the lighting device 320. The top 330 is opposite to the base 322 along the longitudinal axis A. The first LED filament 100 is arranged at a first angle θ1 with the longitudinal axis. In this case, the angle θ1 is defined as the angle formed from the longitudinal axis A to the first LED filament 100 in a clockwise direction. Furthermore, the first LED filament 100 is arranged such that its first side 105 (and therefore the first surface of its carrier) generally faces the top 330 of the lighting device 320, rather than the base 322.

[0087] The second LED filament 200 is arranged at a second angle θ2 with respect to the longitudinal axis A. In this case, angle θ2 is defined as the angle formed from the longitudinal axis A to the first LED filament 200 in a counterclockwise direction. Furthermore, the second LED filament 200 is arranged such that its first side 205 (and therefore the first surface of its carrier) generally faces the base 322, rather than the top 330 of the lighting device 320.

[0088] refer to Figure 3 and Figure 4 This section will describe different LED filament arrangements according to some embodiments.

[0089] Figure 3 This is a schematic diagram of an LED filament arrangement 441 according to some embodiments. Figure 3 The LED filament arrangement 441 includes two first LED filaments 100, which can be equivalent to the one mentioned above. Figure 2 The first LED filament 100 is described. The LED filament arrangement also includes two second LED filaments 200, which are equivalent to those described above. Figure 2 The second LED filament 200 is described.

[0090] All LED filaments 100 and 200 are arranged at substantially equal angles relative to the longitudinal axis A. Each LED filament 100 and 200 is arranged such that its entire length is positioned at substantially the same distance from the longitudinal axis A. Therefore, the LED filaments are angled "towards" relative to the longitudinal axis and do not face or move away from the longitudinal axis A.

[0091] In the LED filament arrangement 441, LED filaments 100 and 200 are evenly spaced and arranged such that their endpoints coincide with the corners of the rectangular cuboid 442. The first LED filament 100 forms the diagonals of opposite sides of the cuboid. The second LED filament 200 forms the diagonals of opposite sides of the cuboid. Both LED filaments 100 and 200 are angled to the same side, such that no endpoint is located at the same corner of the rectangular cuboid.

[0092] It should be understood that other embodiments based on this configuration are conceivable. In such a configuration, the LED filament is angled relative to the longitudinal axis A, but the LED filament extends in a direction that does not intersect with the longitudinal axis A. More generally, the LED filament extends in a plane representing the face of a cuboid centered on the longitudinal axis A.

[0093] Figure 4 Different examples of LED filament arrangement 443 are shown, which also includes two first LED filaments 100 and two second LED filaments 200, which may be equivalent to the first LED filaments 100 and the second LED filaments 200, respectively, as described above with reference to the preceding figures.

[0094] In the LED filament arrangement 443, LED filaments 100 and 200 are evenly arranged around the longitudinal axis A. Two first LED filaments 100 are arranged opposite each other. Two second LED filaments 200 are arranged opposite each other. Furthermore, all LED filaments are arranged at the same angle to the longitudinal axis A. The bottom end of each LED filament 100 and 200 is arranged at the same distance from the longitudinal axis A, and the top end of each LED filament 100 and 200 is arranged at a longer distance from the longitudinal axis A. Therefore, the LED filaments 100 and 200 of the LED filament arrangement 443 coincide with the edge of the inverted pyramid 444.

[0095] It should be understood that Figure 3 and Figure 4 These are illustrative examples describing different types of LED filament arrangements that can be arranged within lighting devices as described in this disclosure (such as references). Figure 2 The described lighting device 320). Other LED filament arrangements may include more or fewer first LED filaments and / or second LED filaments. In some LED filament arrangements, the LED filaments may together describe other geometries (such as prisms or antiprisms), or be arranged in other ways that conform to the angles defined in this invention.

[0096] In a specific example, LED filaments can be arranged in a zigzag or crown shape, where the endpoints of two adjacent LED filaments are arranged close to each other.

[0097] See Figure 5 and Figure 6 This document describes various methods, according to some embodiments, for controlling the power supply to at least one first LED filament and at least one second LED filament. These methods can be implemented in a controller of a lighting device, such as those referenced above. Figure 2 The controller 326 is described.

[0098] Figure 5 The relationship between the input signal provided to the controller and the corresponding power supply level provided from the controller to at least one first LED filament and at least one second LED filament is shown 550.

[0099] For very low input signal levels, no power is supplied to any LED filaments. As the input signal increases (from left to right along the horizontal axis), exceeding the first input signal level i1 (or the first threshold), the controller begins to gradually increase the power supply to (multiple) second LED filaments 552, from the first power supply level p1 to the second power supply level p 22 The power supply 552 to (multiple) second LED filaments does not increase to the second power supply level p. 22 The above, but as the input further increases, it exceeds the intermediate power level i n (or a second threshold) and remain at the same level. Conversely, as the input signal increases, the controller begins to gradually increase the power supply 554 to at least one first LED filament. The power supply 554 to the (multiple) first LED filaments increases from a first power level p1 to a second power level p. 21 In this embodiment, the first and second LED filaments share the same first power level p1, but have different second power levels p2. 21 p 22 In some implementations, the first power level p1 can be equal to zero.

[0100] Therefore, when the input level increases from the first input level i1 to the intermediate input level i n At that time, the lighting equipment, which is equipped with a controller, emits light with a second CCT at increased intensity. When the input level changes from the intermediate level i... n When the input level is increased to the second level i2, the intensity of the emitted light increases, and the CCT of the emitted light also increases.

[0101] In this embodiment, if the input increases above the second input level i2 (at which both the first and second LED filaments are at their second power levels), the controller does not further increase the power level. In this embodiment, the relationship between the input level and the corresponding power supply level does not depend on whether the input increases or decreases; a specific level of the input signal provides the same power supply level.

[0102] Figure 6 Another relationship 560 between the controller's input signal and the corresponding power supply levels provided to at least one first LED filament and at least one second LED filament is shown.

[0103] exist Figure 6 In the above, as the input signal increases from the first input signal level i1, the power supply level 562 of the second LED filament gradually increases from the first power level p1 to the second power level p2, as shown in the reference... Figure 5 In the method described, if the input signal increases further, exceeding the intermediate level i n The power supply level 562 of the second LED filament gradually decreases towards the first power level p1, while the power supply level 564 of the first LED filament simultaneously increases from the first power level p1 to the second power level p2.

[0104] Therefore, when the input level increases from the first input level i1 to the intermediate input level i n At the second input level i2, the lighting device emits light with increased intensity and a second CCT. When the input level increases from the intermediate level to the second input level i2, the intensity of the emitted light can remain the same, but the CCT of the emitted light changes. At the second input level i2, the lighting device emits light with the second CCT.

[0105] Those skilled in the art will recognize that the present invention is by no means limited to the preferred embodiments described above. Rather, many modifications and variations are possible within the scope of the appended claims.

[0106] For example, by programming the input signal, the power supply level of the first and second LED filaments can be adjusted in a manner that changes the direction of the emitted light by the lighting device.

[0107] For example, the arrangement of the LED filaments can be varied, as long as the angle of the LED filaments conforms to the provisions in the claims.

[0108] Although the features and elements have been described above in specific combinations, each feature or element may be used alone without other features and elements, or in various combinations with or without other features and elements.

[0109] Additionally, from a study of the drawings, disclosure, and appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not imply that combinations of these features cannot be used advantageously.

Claims

1. A lighting device (320), comprising: At least one first light-emitting diode (LED) filament (100) is adapted to emit light having a first correlated color temperature (CCT); At least one second LED filament (200) is adapted to emit light having a second CCT, the second CCT being different from the first CCT; Each of the first LED filament and the second LED filament has a first side and a second side, the first side and the second side are arranged opposite each other and extend along the elongation direction of each of the first LED filament and the second LED filament, and each LED filament is arranged to emit a first portion (112) of light from the first side (105) of each LED filament and a second portion (114) of light from the second side (107) of each LED filament, wherein the first portion (112) of light is larger than the second portion (114) of light. The base (322) is capable of connecting to a light fixture socket; and A light-transmitting enclosure (324) is mounted on the base and at least partially encloses the at least one first LED filament and the at least one second LED filament; The longitudinal axis (A) extends from the base to the top (330) of the enclosure. Each of the at least one first LED filaments is arranged at a first angle to the longitudinal axis. ), wherein the first side of each LED filament in at least one first LED filament faces the top of the enclosure; and Each of the at least one second LED filaments is arranged at a second angle to the longitudinal axis. ), wherein the first side of each LED filament in at least one second LED filament faces the base.

2. The lighting device according to claim 1, wherein the first angle is in the range of 20° to 70°, and wherein the second angle is in the range of 20° to 70°.

3. The lighting device according to claim 1 or 2, wherein the first angle is at least equal to the second angle.

4. The lighting device according to claim 1 or 2, wherein the difference between the first CCT and the second CCT is at least 500 K.

5. The lighting device according to claim 1 or 2, wherein the difference between the first CCT and the second CCT is less than or equal to 2000 K.

6. The lighting device according to claim 1 or 2, wherein the first CCT is higher than the second CCT.

7. The lighting device according to claim 1 or 2, wherein the first CCT is greater than or equal to 2700 K.

8. The lighting device according to claim 1 or 2, wherein the second CCT is less than or equal to 2500 K.

9. The lighting device according to claim 1 or 2 is also suitable for emitting light with an average CCT in the range of 2700 K to 3500 K.

10. The lighting device according to claim 1 or 2, wherein each of the at least one first LED filament and each of the at least one second LED filament is arranged to emit at least X% of the light of the LED filament from a first side of the LED filament, wherein X is in the range of 60 to 90.

11. The lighting device according to claim 1 or 2, wherein the number of the at least one first LED filament is in the range of 2 to 6; and wherein the number of the at least one second LED filament is in the range of 2 to 6.

12. The lighting device according to claim 1 or 2, comprising at least two first LED filaments, wherein the number of said at least two first LED filaments is greater than the number of said at least one second LED filament.

13. The lighting device according to claim 1 or 2, further comprising a controller (326) configured to provide a first power supply to the at least one first LED filament and a second power supply to the at least one second LED filament.

14. The lighting device of claim 13, wherein the controller is configured to: When the input signal increases from the first input level i1 to the second input level i2, the power supply (552) to the at least one second LED filament is increased from the first power level p1 to the second power level p2. 22 Subsequently, the power supply (554) to the at least one first LED filament is increased from the first power level p1 to the second power level p. 21 ; and / or When the input signal decreases from the second input level i2 to the first input level i1, the power supply to the at least one first LED filament will be changed from the second power level p. 21 The power supply to the at least one second LED filament is reduced to the first power level p1, and then the power supply to the second power level p1 is reduced to the second power level p1. 22 Reduce to the first power level p1.

15. The lighting device of claim 13, wherein the controller is further configured to: While increasing the power supply (564) to at least one first LED filament from a first power level p1 to a second power level p2, the power supply to the at least one second LED filament is decreased (562); and / or While reducing the power supply to the at least one first LED filament from the second power level p2 to the first power level p1, the power supply to the at least one second LED filament (200) is increased.

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