Adjustable light-emitting device

Abstract

Total color temperature (CT tot 1. A light emitting device configured to adjustably emit light having a color temperature (CT1), the light emitting device comprising: a support having a first major surface and an opposite second major surface; a first light source disposed on the first major surface and configured to emit light having a first color temperature (CT1) that is adjustably adjustable within a first range from a first low color temperature to a first high color temperature; a second light source disposed on the second major surface and configured to emit light having a second color temperature (CT2) that is adjustably adjustable within a second range from a second high color temperature to a second low color temperature; and tot a controller configured to individually control the first and second light sources to adjustably adjust CT1 and CT2 from a first state to a second state according to a preselection scheme by increasing CT1 and decreasing CT2 between the first state and the second state such that CT1 remains unchanged.

Description

[Technical Field]

[0001] The present invention relates to a light-emitting device having adjustable color temperature. [Background technology]

[0002] Lamps, luminaires, or lighting devices equipped with a controllable light source, such as a light-emitting diode (LED), may be communicatively connected to a controller or control unit. This may be particularly desirable for lamps capable of emitting light of different colors, such as multicolor filament lamps, in order to facilitate or enable adjustment of the color of light emitted by the lamp. Alternatively or additionally, the dimming of the light source of a lighting device, or the activation / deactivation of the light source, may be controlled by a control unit or controller that transmits control signaling to the lighting device.

[0003] By connecting lamps, luminaires, or lighting devices to a controller, new functions may be enhanced or enabled. The above examples may be useful, for example, in the field of decorative lamps or lighting where the color or intensity of the light source can be adjusted as desired by the user. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] U.S. Patent Application Publication No. 2019 / 041013 discloses a lighting device comprising two or more individually controlled light sources operating within a structure having a ground and ceiling surface. A first light source emits light with a predetermined correlated color temperature upward toward the ceiling portion directly above the lighting device, without being obstructed by the lighting device. A second light source emits light with a predetermined correlated color temperature downward toward the floor surface. A controller individually adjusts the color temperature and intensity of the light sources according to a time schedule.

[0005] In addition to many creative ways of using the controllability of light sources in decorative lights, there may be one new function in the field of lighting fixtures or light engines where the "up and down lighting" function is desired. The object of the present invention is to provide a light emitting device capable of controlling and adjusting the color temperature and luminous flux of its light source.

Means for Solving the Problems

[0006] According to a first aspect of the present invention, this object and other objects are achieved by a light emitting device configured to adjustably emit light having a full color temperature (CT tot ), comprising a support having a first main surface and a second main surface opposite to the first main surface, and a first light source disposed on the first main surface of the support and configured to emit first light having a first color temperature (CT1), wherein the first color temperature is adjustable within a first color temperature range from a first low color temperature (CT1 low ) to a first high color temperature (CT1 high ); a second light source disposed on the second main surface of the support and configured to emit second light having a second color temperature (CT2), wherein the second color temperature is adjustable within a second color temperature range from a second high color temperature (CT2 high ) to a second low temperature (CT2 low ); and a controller configured to individually control the first light source and the second light source so that the first color temperature and the second color temperature can be adjusted from a first state to a second state in accordance with a preselected method such that the full color temperature of the light emitting device remains constant at a certain value in the first state and the second state, by increasing the first color temperature from CT1 low in the first state to CT1 high in the second state, and by decreasing the second color temperature from CT2 high in the first state to CT2 low in the second state.

[0007] Under the full color temperature range, the overall color temperature of the lighting device should be understood. This is the average of the color temperatures of the first and second light sources, taking into account the luminous flux of these light sources.

[0008] It should be noted that in the context of the present invention, equal color temperature may be defined as a difference of less than 300K, more preferably less than 250K, and most preferably less than 200K between the first and second color temperatures.

[0009] The advantage of having the entire color temperature remain constant can be a decorative effect. More specifically, when viewing the light-emitting device directly, the user may distinguish between the different color temperatures of two light sources; for example, the first light source may emit cooler white light, while the second light source may emit warmer white light. At the same time, on a larger scale, when looking at the overall lighting surrounding the light-emitting device, the color temperature remains the same.

[0010] According to the first main embodiment, the luminous flux of the first light source and the luminous flux of the second light source are equal.

[0011] It should be noted that, for equal luminous flux from the first and second light sources, the total color temperature can be defined, for simplicity, as the average of the first and second color temperatures under any given conditions. In the context of the present invention, equal luminous flux can be defined as a difference in luminous flux between the first and second light sources being preferably less than 50 lm, more preferably less than 45 lm, and most preferably less than 40 lm.

[0012] As a result of having equal luminous flux, in order to maintain the total color temperature of the second state at the same level as the total color temperature of the first state, the color temperature changes of the first and second states are equal to their starting points (CT1) in the first state. low and CT2 high ) or their endpoints in the second state (CT1 high and CT2 low Regardless of the above, they must be equal. These embodiments may lead to a symmetrical deco effect in the light-emitting device.

[0013] In the two special cases of this first embodiment, the first color temperature and the second color temperature are equal in either the first or second state and equal to the total color temperature. In other words, the first and second color temperatures either diverge after starting equal or converge after starting differently, while the total color temperature is maintained.

[0014] In yet another special case of the first main embodiment, the first color temperature increases from A to B, while the second color temperature decreases from B to A. In other words: CT1 low =CT2 low and CT1 high =CT2 high .

[0015] The equal luminous flux from the first and second light sources may remain constant during the transition between the first and second states, or may change slightly during the transition, depending on the desired visual effect.

[0016] According to a second primary embodiment, the luminous flux of the first light source and the luminous flux of the second light source are different in the first and second states. Depending on the desired visual effect, the different luminous fluxes of the first and second light sources may remain constant during the transition between the first and second states, or may change slightly during the transition.

[0017] As a result of this embodiment, in the first state, the total color temperature approaches that of the light source with a higher luminous flux. In order to maintain the same total color temperature in the second state, the color temperature of the light source with a lower luminous flux needs to change more significantly, that is, the color temperature range of that light source must be wider than the color temperature range of the other light sources.

[0018] According to a third primary embodiment, the controller is additionally configured to individually control the first luminous flux (F1) of the first light source and the second luminous flux (F2) of the second light source.

[0019] More specifically, the first light source is CT1low The first luminous beam (F1 A ) has CT1 high Then the second beam (F1 B ) may have a second light source, CT2 high The first luminous beam (F2 A ) has CT2 low Then the second luminous beam (F2 B ) may have.

[0020] By having the possibility to control both the color temperature and luminous flux of the first and second light sources, the controller may have a variety of pre-selected control themes that achieve the technical effect of keeping the overall color temperature of the light-emitting device constant while providing visual effects.

[0021] For example, in the first state, the first color temperature and the second color temperature are equal (CT1 low =CT2 high In this case, the color temperature of the first light source and the color temperature of the second light source may vary by different amounts, provided that the luminous flux of the first and / or second light sources is appropriately modified.

[0022] For example, if the color temperature of the first light source is increased more significantly than if the color temperature of the second light source is decreased (|CT1 low -CT1 high |>|CT2 low -CT2 high |) In this case, to compensate for the superior coldness of the light emitted from the first light source, the luminous flux of the second light source is increased (F2 A <F2 B ), and / or the luminous flux of the first light source is reduced (F1 A >F1 B ) is necessary. The reverse is also true: (|CT1 low -CT1 high |<|CT2 low -CT2 high |) then, (F1 A <F1 B ) and / or (F2 A >F2 B ).

[0023] The increase or decrease in the luminous flux of the first and second light sources may be equal, or additionally, the luminous flux of the first and second light sources may be equal in the first or second state (F1 A =F2 A or F1 B =F2 B ) is noteworthy.

[0024] Alternatively, the difference in luminous flux from the first light source from the first state to the second state is not equal to the difference in luminous flux from the second light source from the first state to the second state |F1 A -F1 B |≠|F2 A -F2 B The increase or decrease in the luminous flux of the first and second light sources does not necessarily have to be equal in order to achieve the desired effect of keeping the overall color temperature of the light-emitting device constant.

[0025] According to one embodiment, the light-emitting device comprises at least one light-emitting diode (LED) filament having an elongated support having a first main surface and a second main surface opposite to the first main surface, wherein the first light source is a plurality of first LEDs mounted on the first main surface of the elongated support and configured to emit first light having a first color temperature (CT1), and the second light source is a plurality of second LEDs mounted on the second main surface of the elongated support and configured to emit second light having a second color temperature (CT2).

[0026] This embodiment may have the advantages of a light-emitting device, such as a filament lamp, which can be adjusted from a first symmetrical state to a second state, in which two surfaces can emit light having different color temperatures or colors, while maintaining an invariant overall color temperature of the light emitted into the surroundings by the light-emitting device.

[0027] According to one embodiment of the LED filament, the first plurality of LEDs comprises two or more subsets of LEDs, each subset emitting a different color point and individually controllable by a controller, and the second plurality of LEDs comprises two or more subsets of LEDs, each subset emitting a different color point and individually controllable by a controller.

[0028] According to this embodiment, in order to achieve a specific white temperature (CT1) of the first light source, the intensity and / or activity of two or more subsets of LEDs having different color points may be controlled relative to each other. A similar arrangement may be applied to achieve a specific color temperature (CT2) of light emitted from a second light source.

[0029] According to one embodiment, two or more LED subsets of a first or second plurality of LEDs may include a first subset of LEDs configured to emit cool white light and a second subset of LEDs configured to emit warm white light. In this case, the intensity and / or activity of the subset having warm white light and the subset having cool white light may be controlled relative to each other to obtain a desired color temperature of the first or second light source.

[0030] Additionally or alternatively, for any face of the LED filament, a subset of LEDs from the first or second light source may be controlled to achieve a specific total color point from that particular light source.

[0031] In one embodiment of the LED filament, two or more LED subsets of a first or second plurality of LEDs include a red subset comprising red LEDs, a green subset comprising green LEDs, and a blue subset comprising blue LEDs. As a result, each subset may emit red, green, and blue light.

[0032] According to a second embodiment, a lamp comprising a light-emitting device, a transmissive envelope that at least partially covers the light-emitting device, and a connector for electrically and mechanically connecting the lamp to a socket.

[0033] The connector may be an electrical connector such as an E26 or E27 threaded Edison connector, but is not limited to this.

[0034] It should be noted that the present invention relates to all possible combinations of the features enumerated in the claims. [Brief explanation of the drawing]

[0035] The present invention will be described more fully hereafter with reference to the accompanying drawings, which illustrate currently preferred embodiments of the invention. However, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided for completeness and comprehensiveness and to fully convey the scope of the invention to those skilled in the art. [Figure 1] A light-emitting device according to a first aspect of the present invention is shown. [Figure 2] One embodiment of the pre-selection control method is shown. [Figure 3] One embodiment of the pre-selection control method is shown. [Figure 4] One embodiment of the pre-selection control method is shown. [Figure 5] One embodiment of the pre-selection control method is shown. [Figure 6] This shows one embodiment of a light-emitting device. [Figure 7] The optical temperature / spectrum of the light-emitting device in the first state is shown in the chromaticity diagram. [Figure 8] The optical temperature / spectrum of the light-emitting device in the second state is shown in the chromaticity diagram. [Figure 9]The optical temperature / spectrum of the light-emitting device in the second state is shown in the chromaticity diagram. As shown in the figure, the sizes of the layers and regions are exaggerated for illustrative purposes and are therefore presented to illustrate the general structure of the embodiments of the present invention. Similar reference numerals refer to similar elements throughout. [Modes for carrying out the invention]

[0036] Figure 1 schematically shows a light-emitting device 1 according to a first aspect of the present invention. The first light source 10 is located on the first main surface 42 of the support 40, and the second light-emitting device 20 is located on the second main surface 44 of the support 40 opposite to the first main surface 42. The first light-emitting device has a first low color temperature CT1 low and the first high color temperature CT1 high The second light-emitting device 20 is configured to emit a first light L1 having a first color temperature CT1 that is adjustable between and in a first direction D1, and the second light-emitting device 20 emits a second high color temperature CT2 high and the second low color temperature CT2 low The light-emitting device 1 is configured to emit a second light L2 having a second color temperature CT2 that is adjustable between and in a substantially second direction D2 opposite to the first direction k. tot It emits the full range of color temperatures. The first light source 10 and the second light source 20 are connected to the controller 50 via an electrical connection line 30.

[0037] The graph in Figure 2 shows one embodiment of the pre-selection method of the controller 50. The x-axis represents time t, and the first state t1 and the second state t2 are indicated, while the y-axis represents color temperature (CT). Note that in the embodiments of Figures 2 and 3, it is assumed that the luminous flux F1 of the first light source 10 and the luminous flux F2 of the second light source 20 are equal to each other and remain unchanged from the first state t1 to the second state t2. The controller 50 sets the first color temperature to the CT1 of the first state t1 so that the total color temperature of the light-emitting devices remains constant in the first and second states. low From the second state t1 CT1 highThis increases (L1) and the second color temperature is the CT2 of the first state t1. high From the second state t2 CT2 low The first light source 10 and the second light source 20 are individually controlled to adjust the first and second color temperatures from the first state t1 to the second state t2 according to a pre-selection scheme by decreasing to (L2). As observed, the first color temperature and the second color temperature are equal, and therefore equal to the total color temperature of the first state t1 (CT1). low =CT2 high =CT tot ). The total color temperature of the second state t2 is CT tot To maintain this, the interval range r1 of the first color temperature must be equal to the interval range r2 of the second color temperature. In other words: r1 = |CT1| low -CT1 high |=|CT2 low -CT2 high |=r².

[0038] The graph shown in Figure 3 shows the first color temperature CT1 in the first state t1. low and the second color temperature CT2 high An embodiment of a pre-selection control scheme in which the values ​​are not equal is shown. The controller 50 controls the total color temperature of the light-emitting device 1 in a second state t2 using CT. tot In order to enable this to be maintained, the first color temperature of the second state t2 becomes equal to the second color temperature of the first state (CT1 high =CT2 high ), and the second color temperature of the second state t2 is equal to the first color temperature of the first state t1 (CT2 low =CT1 low Therefore, a decrease in the first color temperature L1 and an increase in the second color temperature L2 must occur. As a result, the interval range of the first color temperature and the interval range of the second color temperature are equal, r1 = r2.

[0039] In the following embodiments of the pre-selection control method (Figures 4 and 5), the luminous flux of the first light source 10 and the luminous flux of the second light source 20 (F1 each) in the first state t1 A and F2 A) are not equal to those light fluxes in the second state t2 (each F1 B and F2 B ): F1 A ≠F1 B and F2 A ≠F2 B . It should also be noted that while the left y-axis continues to represent the color temperature CT, the right y-axis indicates the light flux F.

[0040] In the embodiment of FIG. 4, the first color temperature and the second color temperature in the first state t1 are equal and equal to the full color temperature of the light emitting device 1: CT1 low =CT2 high =CT tot . The light fluxes of the first light source 10 and the second light source 20 are equal in the first state t1: F1 A =F2 A . The controller 50 adjusts the first color temperature along L1 having a section range of r1 and the second color temperature along L2 having a section range of r2 such that the section ranges of the two color temperatures are not equal and the first section range is larger than the second section range: r1 = |CT1 low -CT1 high | > |CT2 low -CT2 high | = r2.

[0041] In such an embodiment of the preselected control method where the adjustable section ranges of the first light source 10 and the second light source 20 are not equal, in order to maintain the full color temperature of the light emitting device 1 at CT tot in the second state t2, the light fluxes of the first light source 10 and the second light source 20 need to be changed in the corresponding opposite directions. In the embodiment of FIG. 4, this means a reduction in the light flux of the first light source 10 and an increase in the light flux of the second light source 20. The changes in the light fluxes of the first light source 10 and the second light source 20 are respectively indicated by the dashed lines L1' and L2'. From this graph, F1 A >F1 B and F2 A <F2 BThis is observed. More simply, a light source with a more drastic change in color temperature (the first light source 10 in this embodiment) also exhibits a decrease in its luminous flux from the first state t1 to the second state t2. The other light source with a less drastic change in color temperature (the second light source 20 in this embodiment) can maintain its luminous flux in the second state t2 in the same way as in the first state t1 (F2 A =F2 B ), or, as in the embodiment shown in Figure 4, it may have an increase in luminous flux.

[0042] In the embodiment shown in Figure 5, the first color temperature and the second color temperature are not equal in the first state t1 (CT1 low ≠CT2 high Additionally, the luminous flux of the first light source 10 and the luminous flux of the second light source 20 in the first state t1 are not equal: F1 A ≠F2 A . Full color temperature CT of light-emitting device 1 tot However, please note that these are values ​​corresponding to the intensity of the luminous flux produced from each of the different color temperatures. The controller has the same total color temperature CT in the second state t2. tot In order to maintain this, the luminous fluxes of the first light source 10 and the second light source 20 need to be adjusted according to the changes in the color temperatures of the first and second light sources.

[0043] Figure 6 shows an embodiment of the LED filament 100 of the light-emitting device 1. In the context of the present invention, the LED filament 100 of the light-emitting device 1 can be described as follows: A first plurality of LEDs 110 are arranged on the first main surface 122 of the elongated support 120. Note that in this specification, the terms “support” and “substrate” may be used interchangeably and, unless otherwise noted, have the same meaning. The LEDs 110 are also covered by a encapsulant 152 that at least partially covers the first main surface 122 of the elongated support 120. These LEDs 110, together with their encapsulant 152, correspond to the first light source 130 of the light-emitting device 1. On the second main surface 124 of the elongated support 120, opposite to the first main surface 122, a second plurality of LEDs 110 are arranged and covered by a encapsulant 154. These LEDs 110, together with their encapsulant 154, correspond to the second light source 140 of the light-emitting device 1. The first light source 130 and the second light source 140 are connected to the controller 50 via an electrical connector 30. The controller individually adjusts the first color temperature of the first light source 130 from a first low color temperature in the first state t1 to a first high color temperature in the second state t2, and the second color temperature of the second light source 140 from a second high color temperature in the first state t1 to a second low color temperature in the second state t2.

[0044] Preferably, the LED filament 100 has a length G and a width W, where G > 5W. The LED filament 100 may be arranged in a linear configuration similar to that in Figure 6, or in a non-linear configuration such as a curved configuration, a 2D / 3D spiral, or a helix.

[0045] The linear arrangement of the LEDs 110 may be in the longitudinal direction of the elongated support 120. The linear arrangement is preferably a matrix of N × M LEDs 110, where N = 1 (or 2), and M is at least 10, more preferably at least 15, most preferably at least 20, for example, at least 30 or 36 LEDs 110.

[0046] The support 120 may be rigid (for example, made from polymer, glass, quartz, metal, or sapphire) or flexible (for example, made from polymer, such as a film or foil).

[0047] A rigid support material may result in better cooling of the LED filament 100, meaning that the heat generated by the LED 110 can be dissipated by the rigid substrate 120.

[0048] The flexible material support 120 can provide a degree of freedom in shape for designing the aesthetic appearance of the LED filament 100 due to its flexibility.

[0049] It should be noted that thermal management of thin, flexible materials is typically inferior to that of rigid materials. However, having a rigid material as the substrate 120 may limit the shape design of the LED filament 100.

[0050] The support 120 may be light-reflective. In this embodiment, the light emitted by the LED 110 is reflected from the surfaces 122 and 124 of the substrate 120 on which the LED 110 is placed, thereby preventing the light from propagating through the filament substrate 120.

[0051] Furthermore, the LED 110 may be configured to emit LED light of various colors or spectra, for example. The encapsulants 152 and 154 may include a luminescent material configured to at least partially convert the LED light into converted white light. The luminescent material may be a phosphor such as an inorganic phosphor, a blue and / or green-yellow and / or orange-red phosphor, and / or a quantum dot or quantum rod.

[0052] Additionally or alternatively, the encapsulants 152 and 154 may include light-scattering materials.

[0053] Each LED 110 of the LED filament 100 may emit white light. The LEDs may emit cool white light or warm white light. The LEDs may be blue LEDs or UV LEDs covered with encapsulants 152, 154 such that the encapsulants 152, 154 contain luminescent material such as phosphor particles. The luminescent material results in wavelength conversion of the light from the LED 110, and the light emitted from this compartment becomes white light, consisting of a mixture of blue / UV light and wavelength-converted light. The white light may have a color temperature on the blackbody line.

[0054] Additionally or alternatively, the LED filament 100 may comprise red (R) and blue (B) LEDs covered by encapsulants 152, 154 such that the encapsulants 152, 154 contain luminescent material.

[0055] Alternatively or concurrently, the LED filament 100 may include groups of red (R), green (G), and blue (B) LEDs 110, and the light emitted from each of the RGB LEDs 110 is combined to produce white light with a cool or warm color temperature. The red, green, and blue LEDs 110 in each group may be arranged as a group, or they may be arranged sequentially along the longitudinal direction of the LED filament 100.

[0056] The white light has an adjustable color temperature. This may be achieved by including at least two different types of LEDs 110, for example, red and blue LEDs. The color temperature of the emitted light can be controlled by controlling the relative intensity of each type of LED 110.

[0057] Additionally or alternatively, the light emitted by the LED filament 100 may be adjustable to any color in the spectrum. This may be achieved by individually controlling the activity and / or intensity of each of the RGB LEDs 110.

[0058] In addition to changing only the overall color temperature and / or luminous flux of the first light sources 10, 130 and the second light sources 20, 140 of the light-emitting device 1, another method for maintaining a constant overall color temperature from the first state t1 to the second state t2 is to change the color of the light emitted from the light sources.

[0059] According to an alternative example of this embodiment, the light emitted by the first light sources 10, 130 and the second light sources 20, 140 in the first state t1 and / or the second state t2 does not have to be white light of different temperatures, and may be, but is not limited to, light having a color other than white, such as red or green. In that case, the sum of the non-white light emitted by the first light sources 10, 130 and the second light sources 20, 140 may lie on a blackbody locus. This may involve the fact that even if the light emitted from each light source is of a different color, the overall light emitted from the light-emitting device may have a white color having a specific color temperature defined by the color temperature of the light-emitting device 1 in the first state t1.

[0060] Figures 7-9 show chromaticity diagrams in which the blackbody locus is shown as a solid line, while the spectral locus is shown as a dashed line. (Total color temperature CT of light-emitting device 1) tot The point X is located on a blackbody locus, depending on how warm or cold the all-white light emitted from the light-emitting device 1 is.

[0061] Figure 7 shows the optical temperature / spectrum of the light-emitting device 1 according to one embodiment in the first state t1. According to this particular embodiment, the total color temperature is around 3500K. From this plot, it can be seen that the first and second color temperatures also lie on point X in the first state.

[0062] Figure 8 shows the temperature / spectrum of the light-emitting device 1 in the second state t2. The first color temperature increases along the blackbody locus from point X to point Z, and it is observable that point z remains on the blackbody locus. This means that the light emitted from the first light sources 10, 130 remains white and is simply a colder temperature in the second state t2. Similarly, the second color temperature decreases along the blackbody locus from point X to point Y, and point y also remains on the blackbody locus. This means that the light emitted from the second light sources 20, 140 remains white and is simply a warmer temperature in the second state t2. The total color temperature is denoted by X and remains the same point (first state t1) as in Figure 7, as is observable.

[0063] Figure 9 shows the optical temperature / spectrum of the light-emitting device 1 according to another embodiment of the pre-selection control method of the controller 50 in the second state t2. In this embodiment, the light from the first light sources 10, 130 is adjusted away from the blackbody locus and toward a color closer to green in the spectrum. The spectra of the first light-emitting devices 10, 130 are shown as point m. Similarly, the spectra of the second light sources 20, 140 are adjusted away from the blackbody locus and toward a color closer to red. This is indicated by point n. The total color temperature of the light-emitting device 1 is CT in the second state t2. tot Note that in order to maintain point X, the color adjustments of the first light sources 10, 130 and the second light sources 20, 140 must be performed in opposite directions within the spectral locus.

[0064] Those skilled in the art will understand 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. For example, one embodiment in which the pre-selection scheme increases or decreases the first and second luminous fluxes along a sinusoidal function having a constant amplitude or alternatively a variable amplitude, rather than along a linear path as shown in all embodiments of this description.

[0065] Furthermore, by examining the drawings, this disclosure, and the appended claims, variations of the disclosed embodiments will be understood by those skilled in the art and can be performed when carrying out the claimed invention. In the claims, the word “comprising” does not preclude other elements or steps, and the indefinite article “a” or “an” does not preclude plural. The mere fact that certain means are enumerated in different dependent claims does not imply that combinations of these means cannot be used advantageously.

Claims

1. Total color temperature (CT ｔｏｔ A light-emitting device configured to emit light in an adjustable manner, having ) A light-emitting diode (LED) filament comprising an elongated support having a first main surface and a second main surface opposite to the first main surface, Disposed on the first main surface of the support body, the first plurality of LEDs configured to emit first light having a first color temperature (CT １ ) and a first luminous flux F １ A first light source, which is a first light source, wherein the first color temperature is adjustable within a first color temperature range having an interval range r1 = |CT １ ｌｏｗ )-CT -CT １ ｈｉｇｈ | from a first low color temperature (CT )-CT -CT １ ｈｉｇｈ | to a first high color temperature (CT １ ｈｉｇｈ ), and a first light source that is adjustable and adjustable within the first color temperature range, Displaced on the second main surface of the support, the second color temperature (CT ２ ) and the second luminous flux F ２ A second light source, which is a plurality of second LEDs configured to emit a second light having a second color temperature (CT), wherein the second color temperature is a second high color temperature (CT). ２ ｈｉｇｈ ) to the second low color temperature (CT ２ ｌｏｗ ) up to the interval range r2 = |CT ２ ｌｏｗ -CT ２ ｈｉｇｈ A second light source that is adjustable within a second color temperature range having |, CT in the first state １ ｌｏｗ From the second state CT １ ｈｉｇｈ By increasing the first color temperature, and the CT in the first state ２ ｈｉｇｈ From the CT of the second state ２ ｌｏｗ By reducing the second color temperature, A controller configured to individually control the first light source and the second light source so as to adjust the first color temperature and the second color temperature from a first state to a second state according to a pre-selection method, The controller ensures that the total color temperature of the light-emitting device remains constant at a constant value in the first and second states. The first luminous beam F １ and the second luminous flux F ２ When r1 < r2, F １ The change is F ２ It is further configured to control such that the change is greater than or less than the change. Light-emitting device.

2. The light-emitting device according to claim 1, wherein the luminous flux of the first light source and the luminous flux of the second light source are equal in the first state and the second state.

3. The light-emitting device according to claim 2, wherein the luminous flux of the first light source and the luminous flux of the second light source remain constant during the transition from the first state to the second state.

4. The light-emitting device according to claim 3, wherein the first color temperature and the second color temperature are equal in the first state or the second state.

5. The light-emitting device according to claim 3, wherein the first color temperature in the first state is equal to the second color temperature in the second state, and the second color temperature in the first state is equal to the first color temperature in the second state.

6. The light-emitting device according to claim 1, wherein the luminous flux of the first light source and the luminous flux of the second light source are different in the first state and the second state.

7. The light-emitting device according to claim 6, wherein the luminous flux of the first light source and the luminous flux of the second light source remain constant during the transition from the first state to the second state.

8. The light-emitting device according to claim 1, wherein the difference in the luminous flux of the first light source from the first state to the second state is different from the difference in the luminous flux of the second light source from the first state to the second state.

9. The first change in color temperature is different from the second change in color temperature (|CT １ ｌｏｗ -CT １ ｈｉｇｈ |≠|CT ２ ｌｏｗ -CT ２ ｈｉｇｈ |), the light-emitting device according to any one of claims 1 to 8.

10. The light-emitting device according to any one of claims 1 to 8, wherein the first plurality of LEDs comprises two or more subsets of LEDs, each subset emitting a different color point and individually controllable by the controller, and the second plurality of LEDs comprises two or more subsets of LEDs, each subset emitting a different color point and individually controllable by the controller.

11. The light-emitting device according to claim 10, wherein two or more LED subsets of the first plurality of LEDs or the second plurality of LEDs include a first subset of LEDs configured to emit white light having a first color temperature and a second subset of LEDs configured to emit white light having a second color temperature, wherein the first color temperature is higher than the second color temperature.

12. The light-emitting device according to claim 10 or 11, wherein two or more LED subsets of the first plurality of LEDs or the second plurality of LEDs include a red subset comprising red LEDs, a green subset comprising green LEDs, and a blue subset comprising blue LEDs.

13. A lamp comprising: a light-emitting device according to any one of claims 1 to 8; a transmissive envelope that at least partially covers the light-emitting device; and a connector for electrically and mechanically connecting the lamp to a socket.

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