Light emitting device with flicker effect

Abstract

A light emitting diode (LED) filament includes a core portion having: an elongate carrier including a first major surface and a second major surface; a plurality of LEDs arranged on at least one of the first major surface and the second major surface of the elongate carrier; a light-transmissive encapsulant encapsulating the plurality of LEDs and at least partially encapsulating the elongate carrier and configured to transmit first light at a first angular distribution, the filament further including a plurality of light-transmissive light guide structures arranged on discrete portions of an outer surface of the encapsulant along a length L of the core portion and arranged to couple-in a portion of the first light and to couple-out second light at a second angular distribution such that the first angular distribution and the second angular distribution are not identical.

Description

Technical Field

[0001] This invention relates to LED filament light-emitting devices. Background Technology

[0002] Incandescent bulbs are being rapidly replaced by LED-based lighting solutions. However, users favor and desire modified lamps that retain the appearance of incandescent bulbs. For this purpose, the infrastructure used to produce glass-based incandescent bulbs can be easily utilized, replacing the filament with LEDs that emit white light. One concept is based on LED filaments placed within such bulbs. The appearance of these lamps is highly desirable because they look very decorative. Therefore, it is desirable to introduce additional visual effects, such as flashing or shimmering effects, into such filament lamps to make them even more decorative.

[0003] In an attempt to provide the latter, WO2017153252 discloses a lighting device comprising an exposed outer surface and at least one primary light source disposed within a cavity. The cavity has an inner surface arrangement including a first surface portion and opposing second surface portions. The primary light source is located on the first surface portion. The second surface portion is translucent, and the primary light source illuminates a plurality of light-emitting zones defined by the translucent second surface, thereby providing dual-function lighting for illuminating a space while simultaneously exhibiting a spatially dynamic flickering light display. While this lighting device is simultaneously configured to provide visually appealing lighting effects, particularly dynamic flickering or shimmering effects, this solution requires the panel to act as a secondary light-emitting surface with anisotropic brightness. Summary of the Invention

[0004] One object of the present invention is to overcome this problem and to provide an LED filament that has a flashing effect directly from the filament.

[0005] This invention relates to an LED filament according to independent claim 1. Preferred embodiments are defined by the dependent claims.

[0006] According to a first aspect of the invention, this and other objectives are achieved by a light-emitting diode (LED) filament comprising a core portion having: an elongated carrier including a first main surface and a second main surface; a plurality of LEDs disposed on at least one of the first and second main surfaces of the elongated carrier and configured to emit light; a light-transmitting encapsulation encapsulating the plurality of LEDs and at least partially encapsulating the elongated carrier, and configured to transmit first light at a first angular distribution; the filament further comprising a plurality of light-transmitting light-guiding structures disposed along a length L of the core portion on discrete portions of an outer surface of the encapsulation, and configured to couple a portion of the first light in and couple a second light out at a second angular distribution such that the second angular distribution is narrower than the first angular distribution. The LEDs may include a plurality of red (R), green (G), and blue (B) LEDs. Additionally or alternatively, the LEDs may include a plurality of white LEDs.

[0007] LEDs can be exclusively arranged on either the first main surface or the second main surface. Alternatively, LEDs can be arranged on both the first main surface and the second main surface.

[0008] The use of light guides implies that the structures have a higher refractive index compared to their surroundings. Therefore, when a portion of the initial light coupled into these structures passes through the body without any significant change in direction, a portion of the initial light coupled into these light guide structures will undergo total internal reflection at the boundary between the internal and external environments of the structure, depending on its angle of incidence, and change direction. The refractive index of the light guide structure can differ from that of the encapsulated material. This can result in light escaping primarily at a second angular distribution from the top and / or sides of the structure, a second angular distribution narrower than the first angular distribution of light leaving the encapsulated material.

[0009] The optical guide structure can be made of materials such as, but not limited to, silicone. The optical guide structure can be flexible. Alternatively, it can be rigid.

[0010] In one embodiment, the carrier is light-transmitting. This allows light emitted by the LED to pass through the thickness of the carrier and exit onto the main surface opposite to the main surface where the LED is located. As a result, light can be distributed from both sides of the LED filament. The carrier can be light-transparent, or preferably light-transparent, allowing light emitted by the LED to pass through the thickness of the encapsulation without any significant reflection or refraction.

[0011] In one embodiment, the light guide structure has an axial dimension D1, a width D2, and a depth D3, wherein the axial dimension D1 extends outward from the outer surface of the package and is greater than the width D2 and the depth D3. In the context of this invention, dimension implies the measurable range of an object, more specifically, the length, width, and depth of the light guide structure in Cartesian coordinates.

[0012] According to one embodiment, the axial dimension of the light guide structure is preferably at least twice the thickness T of the core portion of the filament, more preferably at least three times, and most preferably at least four times. In other words, the light guide structure can have a high aspect ratio. A high aspect ratio means that the length-to-width ratio of the structure is quite high, for example, greater than 2, preferably greater than 3, and most preferably greater than 4. This can provide the benefit of having an even more pronounced flickering appearance through the light guide structure, rather than just a thickened appearance of the core portion of the LED filament.

[0013] In one embodiment, the axial dimension extends in a direction normal to the outer surface of the package. Alternatively, the light guide structure may be arranged with an angle other than that normal to the outer surface of the package, resulting in an inclined arrangement.

[0014] In one embodiment, the light guide structures are arranged on the package such that the spacing P between each consecutive light guide structure is at least equal to the core portion thickness, preferably at least twice the core portion thickness, more preferably at least three times the core portion thickness, and most preferably at least four times the core portion thickness. Again, this can provide the benefit of an efficient flickering appearance through the light guide structures, rather than the thickened appearance of the filament core portion.

[0015] According to one embodiment, the light guide structure has an equivalent form and / or size. This embodiment can result in a regular flickering appearance of the LED filament. In the context of this invention, "form" means the 3D form (morphology) of the light guide element. Furthermore, unless otherwise stated, "shape" means the 2D projection of the structure onto a plane, in other words, the cross-section of the 3D structure in a certain direction. The form of the light guide structure can be a semi-ellipsoid, a rectangle, or any other geometric 3D form. In more general terms, the cross-section of the light guide structure along a certain dimension can remain constant (e.g., in a rectangle), or alternatively, its size and / or shape can be varied (e.g., in an ellipsoid). The light guide structure can have a curved shape. If the direction of the axial dimension of the light guide structure is taken to be parallel to the X-axis in a Cartesian coordinate system, then the curvature can be any axis of that coordinate system. Alternatively, the light guide structure can have a straight shape.

[0016] In alternative embodiments, the light guide structure can have different forms, or alternatively, have the same form but different dimensions. Later embodiments can give the LED filament an irregular flickering appearance.

[0017] According to one embodiment, the spacing between the continuous light guide structures is equal. This gives the LED filament a regular flickering appearance. According to an alternative embodiment, the spacing between the continuous light guide structures can be different. This alternative embodiment can result in an irregular flickering effect for the LED filament.

[0018] According to one embodiment, the light guide structure has an elliptical shape, is concentrically arranged around the core portion of the filament, and the axial dimension of the light guide structure is the maximum axis of the elliptical.

[0019] According to one embodiment, two or more light guide structures are arranged at the same longitudinal position along the length of the core portion of the filament, thereby concentrically surrounding the core portion. According to this embodiment, the two or more light guide structures arranged at the same longitudinal position on the core portion can be arranged circumferentially symmetrically, meaning they will have equal radial distances relative to each other. Alternatively, they can be circumferentially asymmetrical.

[0020] According to one embodiment, the light guide structure is optically transparent. This will essentially eliminate any scattering and / or refraction within the body of the light guide structure.

[0021] According to one embodiment, the light guide structure includes a light-emitting material. To convert light emitted from a colored LED into white light, the light guide structure may include a light-emitting material. These materials may include light-emitting particles embedded within a matrix of the light guide structure, such as, but not limited to, phosphorus-containing particles.

[0022] According to one embodiment, the light guide structure includes a light scattering material. The light scattering material may include light scattering particles embedded within the matrix of the light guide structure, the light scattering particles being derived from materials such as, but not limited to, TiO2, BaSO4, and / or organosilicon particles. These particles can scatter and mix light passing through the bulk of the light guide structure by randomizing the initial direction of light. Additionally, the scattering of light by the scattering particles can enhance the flickering appearance of the LED filament.

[0023] According to one embodiment, the light guide structure has a roughened outer surface. The outer surface of the light guide structure can be roughened by methods such as, but not limited to, etching. The roughened outer surface can have the additional effect of scattering second light when coupled out of the light guide structure. This, in turn, can affect the second angular distribution of the second light. The entire outer surface of the light guide structure can be roughened. Alternatively, only a portion of the outer surface of the light guide structure can be roughened. The degree of roughening can affect the amplitude of light scattering; that is, the higher the roughness, the higher the scattering characteristics can be.

[0024] According to one embodiment, light is arranged to be coupled out only from the end portion of the light guide structure.

[0025] This can be achieved by covering all other parts of the light guide structure with highly reflective materials and / or structures, or alternatively, light-absorbing materials and / or structures, while allowing light to pass through only the end portions. This can help to further reduce the second distribution angle of the light.

[0026] The light guide structure may be transparent for at least 0.5 of the axial dimension defined from the attachment portion to the core portion of the LED filament, preferably 0.7 of the axial dimension, more preferably 0.9 of the axial dimension, and most preferably the entire axial dimension.

[0027] In a later preferred exemplary embodiment based on transparency along the entire axial dimension, the light guide structure may be optically transparent such that a portion of the coupled light undergoes total internal reflection within the light guide structure before being coupled out from the end portion of the light guide structure, preferably undergoing at least two total internal reflections.

[0028] According to the second aspect, a modified light bulb includes at least one LED filament, a transmission housing, and a connector, the transmission housing at least partially surrounding the LED filament, and the connector for electrically and mechanically connecting the light bulb to a socket.

[0029] Note that this invention relates to all possible combinations of the features described in the claims. Attached Figure Description

[0030] This and other aspects of the invention will now be described in more detail with reference to the accompanying drawings, which illustrate embodiments of the invention.

[0031] Figure 1 The modified light bulb, including an LED filament, was showcased.

[0032] Figure 2 An LED filament with a light guide structure was demonstrated.

[0033] Figures 3A-3C Different embodiments of LED filaments with a semi-elliptical light guide structure are shown.

[0034] Figures 4A-4C Different embodiments of LED filaments with light guide structures are shown.

[0035] Figures 5A-5F Radial cross-sectional views of different embodiments of LED filaments with light guide structures are shown.

[0036] Figures 6A-6D Different views of different embodiments of LED filaments with elliptical light guide structures are shown.

[0037] Figure 7 An embodiment of an LED filament with a light guide structure is shown.

[0038] Figure 8 An embodiment of an LED filament with a light guide structure is shown.

[0039] Figures 9A-9B Different views of an embodiment of an LED filament with a light guide structure are shown.

[0040] As shown in the figures, the dimensions of the layers and regions are exaggerated for illustrative purposes, and therefore the dimensions of the layers and regions are provided to illustrate the general structure of embodiments of the invention. Similar reference numerals always refer to similar elements. Detailed Implementation

[0041] The invention will now be described more fully below with reference to the accompanying drawings, in which presently preferred embodiments of the invention are illustrated. 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 will fully convey the scope of the invention to those skilled in the art.

[0042] Figure 1 A modified light bulb 10 is shown, comprising an LED filament 100 housed within a housing 20. The LED filament 100 (explained in more detail below) is connected to an electrical (or mechanical) connector 40 via its connecting end 12 and connecting wire 30. Similar to a typical incandescent light bulb, this is shown... Figure 1 In this document, bulb 10 includes an electrical connector 40 (here, a threaded Edison connector such as E26 or E27) for connecting bulb 10 to an electrical outlet (not shown). Note that in this document, modified bulb and lamp are used to refer to the same object and may be used interchangeably unless otherwise stated.

[0043] The LED filament 100 can be configured to emit white light or light of any other color or spectrum. The LED filament 100 can also be configured to be color-tunable and / or color-temperature tunable (in the case of white light). Then, through... Figure 1 The controller 50 shown controls the tunability. The controller 50 can be configured to control the LED 110 individually.

[0044] In the context of this invention, Figure 1 The LED filament 100 of the lighting device (lamp 10) shown can be described as follows. Figure 2A vertical cross-section of such an LED filament 100 is shown. The LED 110 is disposed on a first main surface 122 of an elongated carrier 120 (e.g., a substrate). Note that the terms "carrier" and "substrate" are used interchangeably herein and are intended to have the same meaning unless otherwise stated. Note that the LED 110 may additionally or alternatively be disposed on a second main surface 124 of the elongated carrier 120. Preferably, the LED filament 100 has a length L and a width W, where L > 5W. The LED filament 100 can be arranged in a manner consistent with... Figure 2 Similar straight configurations, or arrangements that are not straight, such as, for example, curved configurations, 2D / 3D spirals, or coils.

[0045] The linear array of LEDs 110 can be arranged in the longitudinal direction of the elongated carrier 120. The linear array 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, such as at least 30 or 36 LEDs 110.

[0046] The carrier 120 can be rigid (made of, for example, polymer, glass, quartz, metal or sapphire) or flexible (made of, for example, polymer, such as film or foil).

[0047] The rigid substrate 120 can provide better cooling for the LED filament 100, meaning that the heat generated by the LED 110 can be distributed through the rigid substrate 120.

[0048] Due to its flexibility, the carrier 120 of the flexible material can provide shape freedom for designing the aesthetics of the LED filament 100.

[0049] It should be noted that thin, flexible materials generally have poorer thermal management compared to rigid materials. However, on the other hand, having a rigid material as the substrate 120 may limit the shape design of the LED filament 100.

[0050] The carrier 120 is light-transmitting, such as translucent, or preferably light-transmitting. The translucent substrate 120 can be made of, for example, polymer, glass, quartz, etc.

[0051] The advantage of the light-transmitting substrate 120 is that light emitted from the LED 110 can propagate through the substrate 120, resulting in essentially omnidirectional light emission.

[0052] According to the present invention, the LED filament 100 includes a core portion 101, the core portion 101 including a carrier 120, an LED 110, and an encapsulation 130, the encapsulation 130 encapsulating at least a portion of the carrier 120 and the LED. The core portion 101 has a thickness T. Note that the encapsulation 130 may be disposed on a first main surface 122 of the carrier. Additionally (e.g.) Figure 2 (As depicted herein) or alternatively, the package 130 may be disposed on the second main surface 124 of the carrier 120. The package 130 is light-transmitting, such as translucent, or preferably light-transmitting. This allows light emitted from the LED 110 to pass through the body of the package 130 and exit from its outer surface 135. Figure 2 The first light 150 is shown to exit the outer surface 135 of the package 130 at an angle of θ1.

[0053] The LED filament 100 also includes light guide structures 140, 240, 340, 440, 540, 640 arranged at discrete longitudinal positions l1, l2, l3, ..., along the length of the core portion 101 on the outer surface 135 of the package 130. Note that unless otherwise stated, the lengths of the core portion 101 and the filament 100 are considered to be the same and equal to L. The light guide structures 140, 240, 340, 440, 540, 640 have an axial dimension D1, which is preferably larger than other dimensions such as D2. The axial dimension D1 can be considered as the longest range of the light guide structures 140, 240, 340, while D2 can be considered as their width. Since these structures are 3D structures, they also have a third dimension D3, which can be considered as their depth. It is worth noting that although the axial dimension D1 refers to the longest dimension of the light guide structures 140, 240, 340, 440, 540, and 640, the light guide structure may also have a height defined as the distance from the surface of the package (135) to the highest point of the light guide structure extending in the direction normal to the surface of the package (135). The height H and the axial dimension D1 will be equivalent in embodiments where the light guide structures 140, 240, 340, 440, 540, and 640 are arranged normally to the surface of the package (135). However, in embodiments with an inclined structure, the height H will always be less than the axial dimension D1.

[0054] The width D2 and depth D3 of the light guide structures 140, 240, 340, 540, and 640 can be equal, such that they have a symmetrical cross-section normal to the axial direction D1. Alternatively, the width D2 and depth D3 of these structures can be unequal. The light guide structures 140, 240, 340, 540, and 640 are arranged such that they protrude outward from the outer surface 135 of the package 130 and are positioned such that they are spaced apart by a distance P. Figure 2In the LED filament 100, semi-elliptical light guide structures 140 are arranged on the core portion 101 such that their axial dimension D1 extends in a direction normal to the surface 135 of the package 130 (α1 = π / 2). A portion 155 of the first light 150 is coupled into the light guide structure 140. This portion 155 undergoes total internal reflection within the body of the light guide structure, causing a second light 160 with a second angular distribution θ2 to be coupled out from the outer surface 145 of the light guide structure 140. Note that, for a significant flickering effect, the second angular distribution should preferably be smaller than the first angular distribution (θ1 > θ2). Figure 2 In the embodiment, an end portion 147 of the light guide structure 140 is also shown. Light can be arranged to couple out only from this end portion 147, thereby making the second angular distribution θ2 even narrower.

[0055] The number of light guide structures 140, 240, 340, 540, and 640 on the LED filament 100 is preferably at least 5, more preferably at least 10, and most preferably at least 20.

[0056] exist Figure 2 In the embodiment illustrated, the light guide structure 140 includes a light scattering material, such as light scattering particles 146. These particles 146 are embedded in the matrix of the light guide structure 140 and facilitate the mixing of light within the body of these structures 140 before coupling out from the outer surface 145. In the case that the LED 110 is an RGB LED, the light scattering particles 146 can enhance the mixing of RGB colored light and can cause white light to be coupled out from the light guide structure 140. In this particular embodiment, the first light 150 can be colored light, or alternatively, the first light 150 can be white light if the RGB colored light is sufficiently mixed within the body of the package 130 before leaving the outer surface 135 of the package 130, while the second light 160 is sufficiently mixed white light.

[0057] Additionally or alternatively, the light guide structure 140 may include a light-emitting material, such as light-emitting particles 148 embedded within the matrix of these structures 140. These particles can convert blue light emitted from the blue LED 110 into white light. According to this embodiment, the first light 150 exiting from the outer surface 135 of the package 130 may be blue light, while the second light 160 coupled from the light guide structure may be white light. Figures 3a-3c illustrate different embodiments of LED filaments 100 with different arrangements of semi-elliptical light guide structures 140. In Figure 3a, all light guide structures 140 have the same generally semi-elliptical shape. However, although the axial dimension D1 of all light guide structures in Figure 3a is the same, their widths D2, D2', ... are different from each other. Figure 3b shows an embodiment in which the width D2 of the semi-elliptical light guide structures 140 is the same while their axial dimensions D1, D1', ... are different from each other. The difference between the axial dimensions D1, D1', ... of the light guide structures may preferably be at least 20%. In the two embodiments of Figures 3a and 3b, the spacing P between the continuous light guide structures 140 is the same. Figure 3c depicts an embodiment in which the axial dimension D1 and width D2 of the light guide structure 140 are the same, while the spacing P, P', P'', ... between each continuous light guide structure varies.

[0058] exist Figure 2 In all embodiments of the LED filament 100 of Figures 3a-3c, the light guide structures 140 are positioned such that their axial dimensions D1, D1', ... extend in a direction normal to the outer surface 135 of the package 130 (α1 = π / 2). In Figure 4a, semi-elliptical light guide structures 140 of equivalent form and size are positioned on the outer surface 135 of the package such that their axial dimension D1 extends in a direction non-normal to the outer surface 135 of the package (α2 ≠ π / 2), meaning that the light guide structures 140 of Figure 4a are inclined relative to the outer surface 135 of the package 130. Note that all the light guide structures 140 in Figure 4a extend in the same direction: α2 = α′2 = α″2 = ... However, in the alternative embodiment of Figure 4b, the light guide structures 140 are inclined in different directions relative to the surface 135 of the package 130: α2 ≠ α′2 ≠ α″2. The angles can differ from each other, preferably by at least 20°.

[0059] Figure 4c illustrates another embodiment of the LED filament 100, wherein the light guide structure 240 has a rectangular shape. The geometry of the light guide structures 140, 240, 340, 440, 540, and 640 can affect their light guiding characteristics, and thus affect the flickering appearance of the LED filament 100. The spacing P between the continuous light guide structures 240 in Figure 4c and their dimensions D1 and D2 are identical.

[0060] Figure 5 depicts radial cross-sectional views of different embodiments of the LED filament 100, wherein in all cases, more than one semi-elliptical light guide structure 140 is arranged at the same longitudinal position l1 along the length L of the core portion 101. In all embodiments, the light guide structures 140 concentrically surround the core portion 101 of the filament 100. In the views of Figures 5a-5f, the axial dimension D1 is visible together with the depth D3 of the light guide structure. In Figures 5a-5c, two, three, and four light guide structures 140 are arranged radially symmetrically around the core portion 101, respectively. In other words, in Figure 5a, In Figure 5b, And in Figure 5c, Alternatively, as shown in the embodiments of Figures 5d-5f, the optical guide structures 140 surrounding the core portion 101 at the same longitudinal position 11 do not have radial symmetry with respect to each other. For example, in Figure 5e, However, in some embodiments, the light guide structure 140 may be arranged to have mirror symmetry with respect to a certain axis.

[0061] Figure 6a shows a perspective view of a portion of the LED filament 100, in which elliptical light guide structures 340 concentrically surround the core portion 101 of the LED filament 100. In this embodiment of the light guide structures 340, preferably, the width D2 is significantly less than the axial dimension D1 and their depth D3, in order to avoid a thickened appearance of the LED filament 100 and to achieve a flickering effect. Therefore, these light guide structures 340 can resemble a thin disk arranged around the core portion 101 of the filament 100. Figure 6b depicts a radial cross-section of the LED filament 100 through the elliptical light guide structure 340 shown in Figure 6a. It can be seen that the core portion 101 is surrounded by the light guide structure 340. In the embodiment of Figure 6, the light guide structure has a circular cross-section, meaning that the total height H (total extension of the axial dimension on both sides of the core portion 101: D1) is... 1 +D1 2 H is equivalent to depth D3. Alternatively, H ≠ D3, which could then result in a light guide structure 340 with an elliptical radial cross-section. It is also possible that, as shown in Figure 6b, D1... 1 =D1 2 In contrast to the embodiments, the axial dimensional extensions on both sides of the core portion 101 are not equivalent: D1 1 ≠D1 2 This embodiment is illustrated in FIG. 6c, in which the core portion 101 is no longer arranged to pass through the center C of the elliptical light guide structure 340. Alternatively (as shown in the embodiment of FIG. 6d) or alternatively, the core portion 101 may asymmetrically pass through a depth D3 of the light guide structure 340. 1 ≠D3 2Alternatively, the light guide structure 340 will be thicker on one side than on the other side of the core portion 101 of the filament 100.

[0062] Alternatively or additionally, the elliptic light guide structure 340 may not be oriented oriented normally to the surface 135 of the package 130, but may be positioned in a conical manner.

[0063] While the elliptical light guide structure 340 can be achieved by a full rotation of the semi-elliptical structure 140 about the direction of its width D2, a light guide structure in the form of a ring disk can be achieved if the rectangular structure 240 undergoes the same full rotation. Figure 7 The filament 100 of this embodiment, having a light guide structure 440, is shown. As observed, the core portion 101 of the filament passes through the annular disk light guide structure 440. These structures differ from the thin disk 340 mentioned in the description of FIG. 6 in that the side facets 443 of the annular disk 440 are flat and do not have the curvature of the ellipsoidal disk 340. This can affect the light guide characteristics and thus the flickering appearance of the filament 100.

[0064] Figure 8 Another embodiment of an LED filament 100 with a light guide structure 540 is shown, which has a significantly higher aspect ratio compared to all the previous embodiments described above. The aspect ratio (D1 / D2) of the light guide structure 540 can preferably be about 5. The light guide structure 540 can then be referred to as a needle-type light guide structure. The light guide structure 540 can have an aspect ratio (D1 / D2) of about 10 or even higher. These light guide structures 540 can then be referred to as fiber-type light guide structures.

[0065] Figures 9a and 9b illustrate one embodiment of the bridging filament 1001 from vertical and radial cross-sectional views, respectively. In the depicted embodiment of the bridging filament 1001, two LED filaments 100, 200 are bridged together using a bridging light guide structure 640. The two filaments 100, 200 are depicted having light guide structures 240 on both sides 108, 208 of their bridging sides 107, 207. The thicknesses T1, T2 of the core portions 101, 201 of the LED filaments 100, 200 can be equal or alternatively different. In the embodiment of Figures 9a and 9b, all light guide structures 240, 640 have a rectangular shape. Alternatively, the light guide structures 240, 640 can have different shapes. The axial dimension D1 of all light guide structures 240, 640 is... 1 D1 2 D1 桥 They can be completely equivalent, or alternatively, not equivalent. Similarly, the width D2 of the optical guide structure 240, 640... 1 D2 2 D2 桥and depth D3 1 D3 2 D3 桥 They may be equivalent or alternatively different from each other. In some embodiments, more than one LED filament 100, 200 may be bridged together. The LED filaments 100, 200 may be bridged together in a parallel manner similar to the embodiment of FIG9, or they may be bridged such that they coalesce and / or form a complex structure of bridged filaments 1001.

[0066] Coupled light from each of the filaments 100 and 200 entering the bridging light guide structure 640 can be combined and coupled out from the side surface 645 of the bridging light guide structure 640. Alternatively or additionally, coupled light from each of the LED filaments 100 and 200 can pass through the encapsulations 230 and 130 and / or transmission carriers 220 and 120 of the other LED filament 200 and 100, and coupled out from the core portions 201 and 101 of the filaments 200 and 100. Alternatively or additionally, light can pass through and undergo secondary coupling into a light guide structure 240 located on the sides 208 and 108 of the filaments 200 and 100 opposite to the bridging sides 207 and 107. Light will then be coupled out from these light guide structures 240.

[0067] 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. For example, more than one core portion of the LED filament may be surrounded by the same light guide structure. Additionally, each core portion of the LED filament may have an LED of a particular color, thus emitting a different color compared to each other.

[0068] Furthermore, by studying the accompanying drawings, the disclosure, and the appended claims, a person 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 or steps, and the indefinite articles "a" or "an" do not exclude multiple. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that combinations of these measures cannot be advantageously used.

Claims

1. A light-emitting diode (LED) filament (100), comprising: Core portion (101), which has The elongated carrier (120) includes a first main surface (122) and a second main surface (124) opposite to the first main surface (122). A plurality of LEDs (110) are arranged on at least one of the first main surface (122) and the second main surface (124) of the elongated carrier (120) and are configured to emit LED light. A light-transmitting package (130) encapsulates the plurality of LEDs (110) and at least partially encapsulates the elongated carrier (120), and is configured to transmit first light (150) at a first angular distribution (θ1). as well as Multiple light-transmitting light guide structures (140) are arranged along the length (L) of the core portion (101) on discrete portions of the outer surface (135) of the package (130), and are arranged to couple a portion of the first light (150) into and couple a second light (160) out at a second angular distribution (θ2), such that the second angular distribution (θ2) is narrower than the first angular distribution (θ1); and The light guide structure (140) has an axial dimension (D1), a width (D2), and a depth (D3), and the axial dimension (D1) extends outward from the outer surface (145) of the package (130) and is greater than the width (D2) and the depth (D3).

2. The LED filament (100) according to claim 1, wherein the carrier (120) is light-transmitting.

3. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) of the light guide structure (140) is at least twice the width (D2) of the light guide structure (140).

4. The LED filament (100) according to claim 1 or 2, wherein the light guide structure (140) is a fibrous structure (540) such that the axial dimension (D1) is 10 times larger than the width (D2) of the light guide structure.

5. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) extends in a direction normal to the outer surface (135) of the package (130).

6. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) of the light guide structure (140) is at least twice the thickness (T) of the core portion (101) of the filament (100).

7. The LED filament (100) according to claim 1 or 2, wherein the light guide structure (140) is arranged on the package (130) such that the spacing (P) between each consecutive light guide structure (140) is at least equal to the thickness (T) of the core portion.

8. The LED filament (100) according to claim 7, wherein the spacing (P) between the continuous light guide structures (140) is equivalent.

9. The LED filament (100) according to any one of claims 1, 2 and 8, wherein at least a subset of the light guide structure (140) has an equivalent shape and / or size.

10. The LED filament (100) according to claim 1, wherein the light guide structure (140) has the form of an elliptic, is arranged concentrically around the core portion of the filament, and such that the axial dimension of the light guide structure is the maximum axis of the elliptic.

11. The LED filament (100) according to any one of claims 1, 2, 8 and 10, wherein two or more light guide structures (140) are arranged at the same longitudinal position along the length of the core portion (101) of the filament (100), thereby concentrically surrounding the core portion (101).

12. The LED filament (100) according to any one of claims 1, 2, 8 and 10, wherein the light guide structure is light-transparent such that a portion of the coupled light undergoes total internal reflection within the light guide structure (140) before being coupled out from the end portion (147) of the light guide structure.

13. The LED filament according to any one of claims 1, 2, 8 and 10, wherein light is arranged to be coupled out only from the end portion (147) of the light guide structure (140).

14. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) of the light guide structure (140) is at least 5 times larger than the width (D2) of the light guide structure (140).

15. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) of the light guide structure (140) is at least three times the thickness (T) of the core portion (101) of the filament (100).

16. The LED filament (100) according to claim 1 or 2, wherein the axial dimension (D1) of the light guide structure (140) is at least four times the thickness (T) of the core portion (101) of the filament (100).

17. The LED filament (100) according to claim 1 or 2, wherein the light guide structure (140) is arranged on the package (130) such that the spacing (P) between each consecutive light guide structure (140) is at least twice the thickness (T) of the core portion.

18. The LED filament (100) according to claim 1 or 2, wherein the light guide structure (140) is arranged on the package (130) such that the spacing (P) between each consecutive light guide structure (140) is at least three times the thickness (T) of the core portion.

19. The LED filament (100) according to claim 1 or 2, wherein the light guide structure (140) is arranged on the package (130) such that the spacing (P) between each consecutive light guide structure (140) is at least four times the thickness (T) of the core portion.

20. The LED filament (100) according to any one of claims 1, 2, 8 and 10, wherein the light guide structure is light-transparent such that a portion of the coupled light undergoes at least two total internal reflections within the light guide structure (140) before being coupled out from the end portion (147) of the light guide structure.

21. A modified light bulb (10) comprising at least one LED filament (100) according to any one of the preceding claims, a transmission housing (20) and a connector (40), the transmission housing (20) at least partially surrounding the LED filament (100) and the connector (40) for electrically and mechanically connecting the light bulb (10) to a socket.

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