LED filament device

Abstract

This invention provides an LED filament device comprising a printed circuit board and at least one flexible LED filament having a corresponding length and providing LED filament light in operation; wherein the printed circuit board comprises: a front surface disposed on a first side of the printed circuit board; a back surface disposed on a second side of the printed circuit board, the second side being opposite to the first side; electronic circuitry disposed on the front surface of the printed circuit board and configured to transmit power to the at least one flexible LED filament in operation; and at least one opening extending through the printed circuit board from the first side to the second side; wherein each of the at least one flexible LED filament extends through one or both of the at least one opening; wherein each of the at least one flexible LED filament is partially disposed on the second side of the printed circuit board; wherein each of the at least one flexible LED filament is mechanically and electrically connected to the electronic circuitry on the front surface of the printed circuit board.

Description

Technical Field

[0001] The present invention relates to LED filament devices and corresponding lamps or luminaires including such LED filament devices. Background Technology

[0002] LED-based lighting has revolutionized the global lighting market. LED-based lighting offers improved efficiency in terms of the ratio of light to heat energy, reduced power consumption, and longer operating life. Due to these advantages, conventional lighting equipment is being rapidly replaced by LED-based lighting. This replacement is also known as retrofitting.

[0003] Furthermore, it has been observed that users appreciate retaining the look and feel of incandescent bulbs. Therefore, the global lighting market has witnessed a dramatic rise in the concept of LED filaments, which also possess high decorative appeal. Consequently, LED filaments are being used in many retrofit bulbs.

[0004] However, in addition to retrofitting bulbs, LED filaments are increasingly being used as the primary light source in luminaires themselves. Due to the widespread use of LED filaments, these filaments or LED filament devices require further improvements in terms of light distribution, miniaturization, modularity, thermal efficiency, and / or aesthetic properties. Summary of the Invention

[0005] One object of the present invention is to provide an improved LED filament device that at least mitigates the problems and disadvantages mentioned above. Therefore, the invention is defined by the appended claims. To this end, the present invention provides an LED filament device comprising a printed circuit board and at least one flexible LED filament having a corresponding length and providing LED filament light in operation; wherein each flexible LED filament includes a corresponding main portion extending between a first end and a second end; wherein the printed circuit board includes: a front surface disposed on a first side of the printed circuit board; a back surface disposed on a second side of the printed circuit board, the second side being opposite to the first side; electronic circuitry disposed on the front surface of the printed circuit board and configured to transmit power to the at least one flexible LED filament in operation; at least one opening extending through the printed circuit board from the first side to the second side; wherein each flexible LED filament (of the at least one flexible LED filament) extends through one or both of the at least one opening; wherein the corresponding main portion of each flexible LED filament (of the at least one flexible LED filament) is partially disposed on the second side of the printed circuit board; wherein the first end and the second end of each flexible LED filament (of the at least one flexible LED filament) are mechanically and electrically connected to the electronic circuitry on the front surface of the printed circuit board.

[0006] Therefore, the present invention provides an LED filament device, wherein a printed circuit board includes a front surface disposed on a first side and a back surface disposed on a second side, the second side being opposite to the first side. At least one flexible LED filament is at least partially disposed on the second side of the printed circuit board.

[0007] Since at least one flexible LED filament is partially arranged on the second side of the printed circuit board, extends through at least one opening from the first side to the second side of the printed circuit board, and is mechanically and electrically connected to electronic circuitry on the front surface of the printed circuit board, the LED filament device according to the invention advantageously separates the irradiation function of the LED filament device from its electronic and mechanical functions.

[0008] Therefore, the LED filament device according to the present invention improves the light distribution and aesthetic appearance of the flexible LED filament on the second side, because the second side of the printed circuit board only exposes the flexible LED filament and does not expose the electronic circuitry or mechanical connections arranged to power the flexible LED filament.

[0009] Furthermore, the LED filament device according to the invention facilitates modularity and assembly because both electronic circuitry and mechanical connections are confined to the first side of the printed circuit board.

[0010] Furthermore, while the electrical and mechanical characteristics of the LED filament assembly can be arranged on the front surface and the first side, the second surface and the second side provide freedom for the design layout of the flexible LED filament, which can be completely dedicated to the light distribution of the LED filament device in the on state and the visual appearance in the off state.

[0011] As mentioned, each flexible LED filament according to the invention may include a main portion, a first end, and a second end, wherein the main portion extends between the first end and the second end, wherein the main portion of the flexible LED filament is partially disposed on a second side of a printed circuit board, and wherein the first end and the second end are partially disposed on a first side of a printed circuit board, and wherein the first end and the second end are configured to mechanically and electrically connect the flexible LED filament to electronic circuitry on the front surface of the printed circuit board.

[0012] In one relevant example, at least one opening includes a first opening and a second opening, wherein a first end of a flexible LED filament extends through the first opening, and wherein a second end of the flexible LED filament extends through the second opening.

[0013] In one embodiment, an LED filament device according to the invention is provided, wherein at least one flexible LED filament comprises N flexible LED filaments; wherein at least one opening is included in the N and 2 The opening between N. In one embodiment, N ≥ 3. For example, N can be N = 3.

[0014] For example, considering the case where the number N is N=1, a single flexible LED filament is provided. Also considering that, according to the invention, only one opening is provided, the single flexible LED filament can extend twice through the single opening, such that the first and second ends of the flexible LED filament can be connected to electronic circuitry on the first side of a printed circuit board.

[0015] In one embodiment, the at least one opening is at least one through-hole. In another embodiment, the at least one opening is at least one slit. Therefore, the printed circuit board may include at least one through-hole and / or at least one slit extending through the printed circuit board from a first side to a second side.

[0016] The slot alternative can be described as a cut. The at least one slot can be arranged around the circumference of the printed circuit board. Therefore, in the example, the slot alternative can be a notch.

[0017] As mentioned, each flexible LED filament has a corresponding length. In one embodiment, at least 70% of the corresponding length of each flexible LED filament in at least one flexible LED filament is arranged on the second side of the printed circuit board. For example, at least 80% of the corresponding length of each flexible LED filament in at least one flexible LED filament may be arranged on the second side of the printed circuit board.

[0018] As mentioned, each flexible LED filament has a corresponding length. In one embodiment, at least 5% of the corresponding length of each flexible LED filament of at least one flexible LED filament is arranged on a first side of the printed circuit board. For example, at least 10% of the corresponding length of each flexible LED filament of at least one flexible LED filament may be arranged on a first side of the printed circuit board. In various aspects, up to 20% of the corresponding length of each flexible LED filament of at least one flexible LED filament may be arranged on a first side of the printed circuit board.

[0019] In one embodiment, the back surface has a higher reflectivity for LED filament light than the front surface of the printed circuit board. In one embodiment, the back surface has a reflectivity value of at least 80% (such as, for example, at least 85%) for the LED filament light. This provides improved efficiency of the LED filament light coupled from the LED filament assembly during operation. For example, in one embodiment, the difference in reflectivity between the first and second surfaces is at least 5%, preferably at least 10%, and most preferably at least 20%. This counteracts unwanted stray light emitted from at least one flexible LED filament.

[0020] In one embodiment, the back surface is diffusely reflective. This does not provide specular reflection of the LED filament light, making the flexible LED filament more visible during operation.

[0021] In one embodiment, the printed circuit board is a metal core printed circuit board (MCPCB). Such an embodiment is advantageous because metal core printed circuit boards provide improved thermal performance and mechanical stability.

[0022] In one embodiment, the electronic circuitry includes an on-board driver (DoB).

[0023] In one embodiment, the LED filament device includes at least one module disposed on the front surface of a printed circuit board; wherein the at least one module is mechanically and electrically connected to electronic circuitry on the front surface of the printed circuit board; wherein the at least one module includes one or more of a driver, a controller, a communication module, and / or a sensor.

[0024] Therefore, in other words, the LED filament device includes at least one of a driver, a controller, a communication module, and a sensor; wherein the driver, controller, communication module, and / or sensor are arranged on the front surface of a printed circuit board.

[0025] As mentioned, each flexible LED filament has a corresponding length. In one embodiment, at least 80% of the corresponding length of each flexible LED filament in at least one flexible LED filament is arranged on a second side of a printed circuit board and between a back surface and a virtual plane parallel to the back surface; wherein the virtual plane is at an offset distance of up to 60 mm from the back surface.

[0026] In another embodiment, at least one flexible LED filament comprises a plurality of curves in a plane parallel to the back surface, wherein each curve comprises a curvature angle of at least 45 degrees.

[0027] In one embodiment, at least a portion of the LED filament has a curved shape and is arranged at a distance equal to or greater than 10 mm from the second surface.

[0028] In one embodiment, each of the at least one flexible LED filaments is mechanically and electrically connected to electronic circuitry at a corresponding connection location on the front surface of a printed circuit board; wherein each of the corresponding connection locations is within a corresponding distance D from an opening in at least one opening; wherein the distance D is equal to at least two and at most ten times the diameter of the corresponding flexible LED filament. The diameter may alternatively be the width of the corresponding flexible LED filament.

[0029] In one embodiment, at least one opening includes a cross-sectional area, wherein the cross-sectional area of ​​each of the at least one opening is at least 1.05 times and at most 4 times the cross-sectional area of ​​the corresponding flexible LED filament in at least one flexible LED filament.

[0030] In one embodiment, the printed circuit board has a maximum size PCBld, wherein at least one opening includes a first opening and a second opening, wherein the first opening and the second opening are spaced 0.2 PCBld to 0.8 The gap distance G within the PCBld range is separated.

[0031] In one embodiment, the cross-sectional shape of at least one opening is one of a circle, a square, a rectangle, a triangle, or a polygon.

[0032] In one embodiment, the LED filament device includes a housing having a light-emitting window and housing a printed circuit board, wherein a second side of the printed circuit board faces the light-emitting window.

[0033] In all respects, at least 80% of the corresponding principal portion of each flexible LED filament in at least one flexible LED filament is arranged substantially parallel to the printed circuit board. For example, each flexible LED filament in at least one flexible LED filament may be arranged on a printed circuit board. Each flexible LED filament in at least one flexible LED filament may be adjacent to the printed circuit board.

[0034] Therefore, in an embodiment, at least 80% of the length of each flexible LED filament in at least one flexible LED filament can be arranged parallel to the printed circuit board.

[0035] A further object of the present invention is to provide an improved lamp or luminaire that at least mitigates the problems and disadvantages mentioned above. To this end, the present invention provides a lamp or luminaire comprising at least one LED filament assembly according to any one of the preceding claims. The luminaire may, for example, be a spotlight or a downlight.

[0036] In the first paragraph, the present invention provides an LED filament device comprising a printed circuit board and at least one flexible LED filament having a corresponding length and providing LED filament light in operation; wherein the printed circuit board comprises: a front surface disposed on a first side of the printed circuit board; a back surface disposed on a second side of the printed circuit board, the second side being opposite to the first side; electronic circuitry disposed on the front surface of the printed circuit board and configured to transmit power to the at least one flexible LED filament in operation; and at least one opening extending through the printed circuit board from the first side to the second side; wherein each flexible LED filament (of the at least one flexible LED filament) extends through one or both of the at least one opening; wherein each flexible LED filament (of the at least one flexible LED filament) is partially disposed on the second side of the printed circuit board; wherein each flexible LED filament (of the at least one flexible LED filament) is mechanically and electrically connected to the electronic circuitry on the front surface of the printed circuit board. Attached Figure Description

[0037] The present invention will now be further illustrated with the aid of illustrative, non-limiting drawings:

[0038] Figure 1 An embodiment of the LED filament device according to the present invention is schematically depicted;

[0039] Figure 2 An embodiment of the LED filament device according to the present invention is schematically depicted;

[0040] Figure 3 An embodiment of a lamp according to the present invention is illustrated schematically;

[0041] Figure 4 An embodiment of the LED filament device according to the present invention is schematically depicted;

[0042] Figure 5 An embodiment of the LED filament device according to the present invention is schematically depicted;

[0043] Figure 6 An embodiment of the LED filament device according to the present invention is illustrated schematically. Detailed Implementation

[0044] Due to their increasing number of implementations in various applications, LED filaments or LED filament devices require further improvements in terms of light distribution, miniaturization, modularity, thermal efficiency, and / or aesthetic characteristics.

[0045] LED filaments provide LED filament light and include multiple light-emitting diodes (LEDs) arranged in a linear array. Preferably, the LED filaments have a length L and a width W, where L > 5W. The LED filaments can be arranged in a straight configuration or in 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, such as a film or foil).

[0046] 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 may be reflective or transmissive, such as translucent and preferably transparent.

[0047] LED filaments may include encapsulations that at least partially cover at least a portion of a plurality of LEDs. The encapsulations may also at least partially cover at least one of a first main surface or a second main surface. The encapsulations may be a polymer material, which may be flexible, such as, for example, silicone. Furthermore, the LEDs may be arranged to emit LED light of, for example, different colors or spectra. The encapsulations may include a light-emitting material configured to at least partially convert the LED light into converted light. The light-emitting material may be a phosphor, such as an inorganic phosphor and / or a quantum dot or quantum rod. LED filaments may include a plurality of sub-filaments.

[0048] Figure 1 An LED filament device 10 according to the invention is illustrated schematically by way of non-limiting example. The LED filament device 10 includes at least one flexible LED filament 11, 12. Here, for illustrative purposes, the LED filament device 10 includes two flexible LED filaments 11, 12, namely, a first flexible LED filament 11 and a second flexible LED filament 12. Thus, at least one LED filament includes a number of flexible LED filaments N=2. The number may alternatively be any other integer N. The flexible LED filaments 11, 12 are arranged to provide LED filament light in operation. The LED filament light may include illumination characteristics such as color temperature.

[0049] Here, each of the at least one flexible LED filament 11, 12 is of the same type. This means that the color spectrum of the LED filament light output by the flexible LED filaments can be the same. Alternatively, the flexible LED filaments can be different, for example, of different types. That is, in an alternative example, at least one flexible LED filament according to the invention is a plurality of flexible LED filaments, wherein at least two of the plurality of flexible LED filaments are different. This means that the color spectrum of the filament light output by the flexible LED filaments can be different.

[0050] refer to Figure 1 The LED filament device 10 according to the present invention includes a printed circuit board 13 (PCB). Although optional, the printed circuit board may be, for example, a metal core printed circuit board (MCPCB). The printed circuit board 13 according to the present invention includes a front surface 14 and a back surface 15. The front surface 14 is disposed on a first side 1 of the printed circuit board 13. The back surface 15 is disposed on a second side 2 of the printed circuit board 13. The second side 2 is thus opposite to the first side 1.

[0051] Still referencing Figure 1 The printed circuit board 13 includes electronic circuitry 16. The electronic circuitry is configured to deliver power to at least one flexible LED filament 11, 12 during operation. The electronic circuitry 16 is disposed on the front surface 14 of the printed circuit board 13. In this example, the electronic circuitry is confined to the front surface 14.

[0052] Although optional, electronic circuitry 16 includes a driver 19. This could be, for example, an on-board driver (DoB). Although optional, LED filament device 10, as part of electronic circuitry, includes a controller 17. This could be a microprocessor. Although optional, LED filament device 10, as part of electronic circuitry, includes a sensor 18. This could be, for example, a light sensor, a temperature sensor, a microphone, a voltage sensor, a GPS receiver, and / or a radio (sensor) for performing communication and / or radio frequency-based sensing. Although optional (not depicted), LED filament device, as part of electronic circuitry, could include a communication module. The communication module could be, for example, a radio module, or, for example, a Bluetooth, ZigBee, and / or Wi-Fi chip, such as a Bluetooth-ZigBee combo chip. Alternatively, however, the communication module could include a radio frequency transceiver, for example, for cellular communication.

[0053] The printed circuit board 13 also includes at least one opening 4, 5, 6, 7, which extends through the printed circuit board 13 from the first side 1 to the second side 2. Here, the opening is a through-hole. Alternatively, the opening may be a slit. However, alternatively, the opening may be a slit, such as a notch, arranged at the outer periphery of the printed circuit board.

[0054] Still referencing Figure 1 Through-holes 4, 5, 6, and 7 include a circular cross-sectional shape. In alternative embodiments, the cross-sectional shape may be polygonal, square, triangular, elliptical, and / or star-shaped. In various aspects, such star-shaped through-holes may also be used to clamp flexible LED filaments protruding through the star-shaped through-holes. In other alternative aspects, the printed circuit board may include protrusions that partially project (or extend) into the opening (i.e., a circular through-hole), wherein the protrusions are configured to (releasably) secure (or clamp) the flexible LED filament within the opening (i.e., a circular through-hole). Furthermore, in other alternative aspects, the (inner) surface of the through-hole may include a higher surface roughness value relative to the front and back surfaces, wherein the surface roughness value is suitable for keeping the flexible LED filament substantially stationary within the through-hole.

[0055] Still referencing Figure 1 According to the present invention, each of at least one flexible LED filament 11, 12 extends through two of at least one opening 4, 5, 6, 7. More specifically, a first flexible LED filament 11 extends through a first opening 4 and a second opening 5 in a printed circuit board 13, and a second flexible LED filament 12 extends through a third opening 6 and a fourth opening 7 in the printed circuit board 13. Alternatively, each of the at least one flexible LED filament may extend through one of the at least one opening, such that the flexible LED filaments share an opening.

[0056] Still referencing Figure 1 At least one of the flexible LED filaments 11, 12 is partially arranged on the second side 2 of the printed circuit board 13. More specifically, each of the at least one flexible LED filament 11, 12 has a corresponding length. Here, at least 70% of the corresponding length of each flexible LED filament 11, 12 is arranged on the second side 2 of the printed circuit board 13. Thus, the majority of the flexible LED filament is arranged on the second side 2 and the back surface 15.

[0057] Here, although optional and not essential, the first flexible LED filament 11 and the second flexible LED filament 12 include multiple curves in a plane parallel to the back surface, wherein each curve includes a curvature angle of at least 45 degrees. Therefore, at least one flexible LED filament 11, 12 can be bent in a plane parallel to the back surface 15. This allows for different optical patterns to be achieved for the LED filament light emitted from the LED filament assembly.

[0058] More specifically, here, each of at least one flexible LED filament 11, 12 is arranged between a back surface 15 and a virtual plane 9, the virtual plane 9 being parallel to the back surface. The virtual plane 9 may be located at an offset distance from the back surface 15. This offset distance may, for example, be related to the thickness (or diameter, or width) of the flexible LED filament 11, 12. For instance, the offset distance may be at least four times the thickness (or diameter, or width) of the flexible LED filament in at least one of the LED filaments.

[0059] Here, although optional, the back surface 15 advantageously has a higher reflectivity for LED filament light than the front surface 14 of the printed circuit board 13, allowing the LED filament light to be emitted more efficiently from the LED filament assembly 10. Furthermore, in this example, the back surface may be diffusely reflective. Alternatively, at least 80% of the corresponding length of each flexible LED filament may be arranged on the second side 2 of the printed circuit board 13.

[0060] In addition, still refer to Figure 1 Each of at least one flexible LED filament 11, 12 is mechanically and electrically connected to electronic circuitry 16 on the front surface 14 of a printed circuit board 13.

[0061] Therefore, the present invention provides an LED filament device 10, wherein a printed circuit board 13 includes a front surface 14 disposed on a first side 1 and a back surface 15 disposed on a second side 2, the second side 2 being opposite to the first side 1.

[0062] Still referencing Figure 1 At least one of the flexible LED filaments 11, 12 is mechanically and electrically connected to the electronic circuit 16 at a corresponding connection location on the front surface 14 of the printed circuit board 13. For convenience, in Figure 1 Only the corresponding connection positions associated with the first flexible LED filament 11 are depicted. That is, the first flexible LED filament 11 includes a first end connected to the electronic circuit 16 at a first connection position 61 and a second end connected to the electronic circuit 16 at a second connection position 71.

[0063] Here, each of the corresponding connection positions 61, 71 is within a corresponding distance D from the corresponding opening 6, 7, wherein the first flexible LED filament 11 extends through the opening 6, 7. More specifically, the distance D is equal to at least two and at most ten times the diameter of the corresponding flexible LED filament in at least one flexible LED filament. In other words, the flexible LED filaments 11, 12 are connected to the electronic circuit 16 substantially close to at least one opening 4, 5, 6, 7 on the front surface 14, such that at least 5% and at most 30% (preferably at most 20%) of the corresponding length of each flexible LED filament in at least one flexible LED filament is arranged on the first side 1 of the printed circuit board 13.

[0064] Since at least one flexible LED filament 11, 12 is partially arranged on the second side 2 of the printed circuit board 13, extending from the first side 1 to the second side 2 through at least one opening 4, 5, 6, 7, and is mechanically and electrically connected to electronic circuitry 16 on the front surface 14 of the printed circuit board 13, the LED filament arrangement 10 advantageously separates the illumination function of the LED filament arrangement from its electronic and mechanical functions. Therefore, the LED filament arrangement improves the light distribution and aesthetic appearance of the flexible LED filaments 11, 12 on the second side 2, because only the flexible LED filaments 11, 12 are exposed on the second side 2 of the printed circuit board 13, and the electronic circuitry 16 or mechanical connections 61, 71 arranged to power the flexible LED filaments are not exposed.

[0065] Because both electronic circuitry and mechanical connections are confined to the first side of the printed circuit board, assembly and modularization have also been improved.

[0066] For example, Figure 2 The LED filament device 20 is schematically depicted, and the LED filament device is based on... Figure 1 The LED filament device is the same as that in the embodiment, but the LED filament device 20 also includes a housing 21 and a light exit window 22. The light exit window 22 may include, for example, an optical element, such as a lens. The housing 31 also houses a printed circuit board, wherein a second side of the printed circuit board faces the light exit window 22. The LED filament device 20 may be, for example, a GU10 spotlight with a flexible LED filament.

[0067] For example, Figure 3 A luminaire 30 is schematically depicted, comprising an LED filament arrangement according to the invention, such as according to... Figure 1 Implementation examples and / or Figure 2 The embodiment of the LED filament device. The luminaire is a spotlight with a tubular housing, but alternatively it can be any other type of luminaire, such as, for example, a light panel or a street light.

[0068] Figure 4An LED filament device 40 according to the invention is illustrated schematically by way of non-limiting example. The LED filament device 40 includes at least one flexible LED filament that provides LED filament light during operation. More specifically, the at least one flexible LED filament comprises a number N of flexible filaments. Here, the number is 3. Therefore, the LED filament device 40 includes a first flexible LED filament 51, a second flexible LED filament 52, and a third flexible LED filament 53.

[0069] The LED filament assembly also includes a printed circuit board 43. The printed circuit board 43 includes a front surface 44 disposed on a first side 58 of the printed circuit board 43 and a back surface 45 disposed on a second side 59 of the printed circuit board 43. The second side 59 is thus opposite to the first side 58.

[0070] The printed circuit board 43 also includes electronic circuitry 46, which is disposed on the front surface 44 of the printed circuit board 43 and configured to deliver power to at least one flexible LED filament 51, 52, 53 in operation.

[0071] The printed circuit board 43 also includes at least one opening extending through the printed circuit board 43 from a first side 58 to a second side 59. Here, the at least one opening includes a first opening 54, a second opening 55, and a third opening 56. At least one flexible LED filament 51, 52, 53 extends through the at least one opening 54, 55, 56. Here, the at least one opening 54, 55, 56 includes a slit. Alternatively, the opening may be a through-hole.

[0072] More specifically, still refer to Figure 4 The first flexible LED filament 51 extends through the first opening 54 and the second opening 55; the second flexible LED filament 52 extends through the second opening 55 and the third opening 56; and the third flexible LED filament 53 extends through the third opening 56 and the first opening 54. Thus, two flexible LED filaments extend through each individual slit.

[0073] Still referencing Figure 4 At least one of the flexible LED filaments 51, 52, and 53 is partially arranged on the second side 59 of the printed circuit board 43. Furthermore, each of the at least one flexible LED filament 51, 52, and 53 is mechanically and electrically connected to electronic circuitry 46 on the front surface 44 of the printed circuit board 43.

[0074] Figure 5A top perspective view of an LED filament device 50 according to the invention is schematically depicted by way of non-limiting example. The LED filament device 50 includes a first flexible LED filament 81, a second flexible LED filament 82, and a printed circuit board 83. The printed circuit board 83 has a triangular shape, but is not limited to that shape. The printed circuit board 83 includes a front surface (not depicted) disposed on a first side (not depicted) of the printed circuit board 83 and a back surface 85 disposed on a second side 92 of the printed circuit board 83, wherein the second side 92 is opposite to the first side (not depicted). The printed circuit board 83 also includes electronic circuitry (not depicted) on the first surface to transmit power to the first flexible LED filament 81 and the second flexible LED filament 82 in operation. The printed circuit board 83 also includes at least one opening 86, 87, 88, 89. Here, at least one opening is a corresponding slit 86, 87, 88, 89 in the circumference of the triangular printed circuit board 83. More specifically, the slits 86, 87, 88, 89 are notches. Still referring to Figure 5 A first flexible LED filament 81 extends through a first slit 86 and a second slit 87, while a second flexible LED filament 82 extends through a third slit 87 and a fourth slit 88. Thus, the first flexible LED filament is partially disposed on the second side 92 of the printed circuit board 83 and is mechanically and electrically connected to electronic circuitry (not depicted) on the front surface of the printed circuit board. Furthermore, although optional, the back surface has a light reflectance value of at least 80% for the LED filament light emitted by the flexible LED filament in operation. The printed circuit board may, for example, be a metal-core printed circuit board.

[0075] Figure 5 The example embodiments provided illustrate one possible configuration by way of non-limiting example. However, other examples can be contemplated similarly, wherein the number of flexible LED filaments, the shape of the printed circuit board, the shape and location of the openings, and the number of flexible LED filaments extending through the openings can be conceived differently in alternative configurations.

[0076] Figure 6 A top perspective view and a bottom perspective view of the LED filament device 600 according to the present invention are illustrated schematically by way of non-limiting example.

[0077] The LED filament assembly 600 includes a printed circuit board 613 and a flexible LED filament 604 having a corresponding length. The printed circuit board includes a front surface 614 disposed on a first side 601 of the printed circuit board 613. The printed circuit board 613 includes a back surface 615 disposed on a second side 602 of the printed circuit board, the second side 602 being opposite to the first side.

[0078] The printed circuit board 613 also includes electronic circuitry 616, which is disposed on the front surface 614 of the printed circuit board 613 and configured to deliver power to at least one flexible LED filament 604 during operation.

[0079] The printed circuit board 613 also includes at least one opening 618 extending through the printed circuit board from a first side 601 to a second side 602. Only one opening 618 exists here. The flexible LED filament 604 extends through the opening 618 and is partially disposed on the second side 602 of the printed circuit board 613. The flexible LED filament 604 is thus mechanically and electrically connected to electronic circuitry on the front surface of the printed circuit board. More specifically, the flexible LED filament 604 includes a main portion 605, a first end 606, and a second end 607. The main portion 605 of the flexible LED filament 604 is partially disposed on the second side 602 of the flexible printed circuit board 613. The first end 606 and the second end 607 both extend through the same opening 618 and are disposed on the first side of the printed circuit board 613. The first end 606 and the second end 607 are configured to mechanically and electrically connect the flexible LED filament 604 to electronic circuitry on the front surface of the printed circuit board 613.

[0080] In the relevant example (not depicted), at least one opening may include a first opening and a second opening, wherein a first end of the flexible LED filament extends through the first opening, and wherein a second end of the flexible LED filament extends through the second opening. Other examples can be conceived similarly.

Claims

1. An LED filament device (10) comprising a printed circuit board (13) and at least one flexible LED filament (11, 12) having a corresponding length and providing LED filament light in operation; Each flexible LED filament includes a corresponding main portion extending between a first end and a second end; The printed circuit board (13) mentioned therein includes: - The front surface (14) is disposed on the first side (1) of the printed circuit board; - A back surface (15) is disposed on a second side (2) of the printed circuit board, the second side (2) being opposite to the first side (1); - An electronic circuit (16) is arranged on the front surface (14) of the printed circuit board (13) and configured to transmit power to the at least one flexible LED filament (11, 12) in operation; - At least one opening (4, 5, 6, 7) extends through the printed circuit board (13) from the first side (1) to the second side (2); Each flexible LED filament (11, 12) extends through one or both of the at least one opening (4, 5, 6, 7); The respective main portion of each flexible LED filament (11, 12) is partially arranged on the second side (2) of the printed circuit board (13); The first and second ends of each flexible LED filament (11, 12) are mechanically and electrically connected to the electronic circuit (16) on the front surface (14) of the printed circuit board (13).

2. The LED filament device according to claim 1, wherein the at least one flexible LED filament comprises N flexible LED filaments; wherein the at least one opening comprises an number of N to 2 The openings between N.

3. The LED filament device according to claim 2, wherein N ≥ 3.

4. The LED filament device according to any one of the preceding claims, wherein the at least one opening is at least one through hole and / or slit.

5. The LED filament device according to any one of the preceding claims, wherein at least 70% of the respective length of each flexible LED filament is arranged on the second side of the printed circuit board.

6. The LED filament device according to any one of the preceding claims, wherein at least 5% of the respective length of each of the at least one flexible LED filament is arranged on the first side of the printed circuit board.

7. The LED filament device according to any one of the preceding claims, wherein the back surface has a higher reflectivity for the LED filament light than the front surface of the printed circuit board.

8. The LED filament device according to any one of the preceding claims, wherein the back surface is diffusely reflective.

9. The LED filament device according to any one of the preceding claims, wherein the printed circuit board is a metal core printed circuit board (MCPCB).

10. The LED filament device according to any one of the preceding claims, wherein the LED filament device comprises at least one module disposed on the front surface of the printed circuit board; The at least one module is mechanically and electrically connected to the electronic circuitry on the front surface of the printed circuit board; The at least one module includes one or more of a driver, a controller, a communication module, and / or a sensor.

11. The LED filament device according to any one of the preceding claims, wherein at least 80% of the respective length of each of the at least one flexible LED filament is arranged on the second side of the printed circuit board and is arranged between the back surface and a virtual plane, the virtual plane being parallel to the back surface; The virtual plane is located at an offset distance of four times the thickness of the flexible LED filament in at least one flexible LED filament.

12. The LED filament device according to any one of the preceding claims, At least 80% of the respective length of each of the at least one flexible LED filaments is arranged on the second side of the printed circuit board and is arranged between the back surface and the virtual plane, the virtual plane being parallel to the back surface. The virtual plane is located at an offset distance of up to 60 mm from the back surface; The at least one flexible LED filament comprises a plurality of curves in a plane parallel to the back surface, wherein each curve comprises a curvature angle of at least 45 degrees.

13. The LED filament device according to any one of the preceding claims, wherein each of the at least one flexible LED filament is mechanically and electrically connected to the electronic circuit at a corresponding connection location on the front surface of the printed circuit board; Each of the corresponding connection positions is within a corresponding distance D from the opening in the at least one opening; The distance D is equal to at least twice and at most ten times the diameter of the corresponding flexible LED filament in the at least one flexible LED filament.

14. The LED filament device according to any one of the preceding claims, wherein the LED filament device includes a housing having a light emission window configured to emit light from the LED filament and housing the printed circuit board, wherein a second side of the printed circuit board faces the light emission window.

15. A lamp or luminaire comprising at least one LED filament device according to any one of the preceding claims.

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