LED lamp filament and bulb lamp using same

Abstract

The utility model relates to the field of illumination, and discloses an LED lamp filament which is characterized in that the LED lamp filament comprises LED chips, a light conversion layer, a layered body and electrodes, the adjacent LED chips are electrically connected, and the LED chips and the electrodes are electrically connected; the light conversion layer wraps the LED chip and at least part of the electrodes, the layered body is arranged on the outer surface of the light conversion layer, at least part of the surface of the light conversion layer is covered with the layered body, the layered body comprises a color agent, and the surface of the LED lamp filament is white when not lightened.

Description

[0001] This divisional application of the present invention was filed with the China National Patent Office on September 27, 2022, with the application number 202222560835.5 and the invention title "An LED filament and a bulb lamp using the LED filament". Technical Field

[0002] This application relates to the field of lighting, and particularly to an LED filament and a bulb lamp using the LED filament. Background Art

[0003] LEDs have the advantages of environmental protection, energy saving, high efficiency, and long life, and thus have been generally emphasized in recent years and gradually replaced the position of traditional lighting fixtures. However, the light emission of traditional LED light sources is directional and cannot provide wide-angle illumination like traditional lighting fixtures. Therefore, applying LEDs to traditional lighting fixtures presents corresponding challenges depending on the type of fixture.

[0004] In recent years, an LED filament that enables an LED light source to emit light similar to a traditional tungsten filament bulb and achieve 360° full-angle illumination has gradually attracted the attention of the industry. The production of this LED filament involves connecting multiple LED chips in series and fixing them on a narrow and elongated glass substrate, then wrapping the entire glass substrate with silicone doped with phosphor powder, and finally making electrical connections. In addition, there is also an LED soft filament, which has a similar filament structure, but the glass substrate part is replaced with a flexible printed circuit board (hereinafter referred to as FPC), enabling the filament to have a certain degree of bendability. However, the soft filament made of FPC has disadvantages such as different coefficients of thermal expansion between the FPC and the silicone coating the filament, resulting in the displacement or even de-bonding of LED chips after long-term use; or the FPC is not conducive to flexible changes in the process conditions.

[0005] The applicant has previously disclosed a soft filament (for example, some embodiments of Chinese Patent Publication No. CN106468405A), which provides a soft filament structure without a carrier substrate, using a flexible and wavelength-converting fluorescent encapsulant to replace the traditional structure that first installs chips on a substrate and then coats phosphor powder / encapsulates. However, the stability of the metal wire bonding between chips in some of the filament structures poses a challenge during bending. When the chips in the filament are densely arranged, if adjacent LED chips are connected by metal wire bonding, it is easy for the stress to be overly concentrated at specific parts of the filament during bending, causing damage or even breakage of the metal wire bonding connecting the LED chips. Therefore, there is still room for improvement in the quality of some embodiments.

[0006] In existing flexible filament products, different types of bulb shells have different requirements for the shape of the LED filament, so the length of the LED filament will have different specifications. For the same filament, with the same number of LED chips, the longer the filament length, the larger the distance between adjacent two LED chips; after the filament is lit, the light spots (or called granularity) observed by the naked eye will be more obvious, seriously affecting the visual comfort of users.

[0007] In the prior art, most LED lamps use a combination of blue LED chips and yellow phosphors to emit white light. However, the emission spectrum of the LED lamp has weak light in the red region and a low color rendering index, making it difficult to achieve a low color temperature. To improve the color rendering index, generally a certain amount of green phosphors and red phosphors are added. However, the relative conversion rate of the red phosphors is relatively low, usually resulting in a decrease in the total luminous flux of the LED lamp, that is, a decrease in luminous efficiency. Secondly, the three types of cone cells in the human eye, namely red, green, and blue, have different sensitivities. If red light is lacking, it will cause the green and blue lights in the human eye to form a cyan image, reducing the color gamut of color reproduction, not only making the lighting scene dull and uninteresting, but also affecting the quality of the lighting environment. In addition, using lighting with high color rendering can improve people's perception of space, while low color rendering will affect the ability to distinguish objects and accurately perceive the surrounding environment.

[0008] Existing LED filaments usually only coat a mixture of phosphor glue on the outer surface of the LED filament. Since phosphor glues with different color temperatures will present different colors after being dried, when multiple LED filaments with different color temperatures are installed, they will show miscellaneous colors at a glance, making the LED lamp not beautiful enough when used as a decorative lamp. Some have graphene glue layers respectively arranged above and below the substrate, and the graphene is modulated into different colors to solve the visual impact caused by the different appearance colors of the phosphor glue layers. However, the production cost of graphene is high and it is easy to pollute the environment.

[0009] The LED chip has a first light-emitting surface and a second light-emitting surface, and the first light-emitting surface and the second light-emitting surface are opposite. The light emitted from the first light-emitting surface (front) faces the top layer, and the light emitted from the second light-emitting surface (back) faces the carrier layer. Generally, the back of a flip-chip or a back-plated surface-mounted LED chip is basically opaque, and there is a large difference in brightness between the front and the back of the LED chip. If the above-mentioned LED chips are used in the LED filament, after the LED filament is wound, the luminous flux in some directions will be less, and the light output of the LED bulb lamp will be uneven.

[0010] In addition, an LED filament is generally disposed in an LED bulb lamp. In order to present aesthetic beauty in appearance and to make the illumination effect of the LED filament more uniform and extensive, the LED filament is bent to present various curves. However, LED chips are arranged in the LED filament, and the LED chips are relatively hard objects, so it is difficult to bend the LED filament into an ideal shape. Moreover, the LED filament is also prone to cracks due to stress concentration during bending.

[0011] In addition, generally, the LED filaments are arranged in a straight line around the core column, and very little light is emitted in the directions near both ends of the LED filaments. When one ends of multiple LED filaments are installed close to each other near the light-emitting top of the bulb, a dark area will be formed in the light-emitting direction of the central axis of the bulb, resulting in uneven spatial distribution of the output light, uneven illuminance distribution, and problems such as the phenomenon of "darkness under the lamp".

[0012] Currently, LED filament lamps generally use a driving power supply to convert alternating current into direct current and then drive the LED filaments to emit light. However, there are ripples in the process of the driving power supply rectifying alternating current into direct current, which will cause stroboscopic light when the LED filaments emit light. In order to reduce or even eliminate the stroboscopic light generated during the light emission of the LED filaments, electrolytic capacitors for removing ripples are usually added to the driving power supply, and the heat generated by the heating elements in the driving power supply will have a great impact on the service life of the electrolytic capacitors.

[0013] When a lighting device includes multiple LED components, different currents are required to drive the multiple LED components. If multiple drivers are used, it will inevitably increase the circuit complexity and circuit cost. Therefore, a shunt circuit is needed to distribute current to the multiple LED components.

[0014] Finally, when the prior art semiconductor dispensing device performs a dispensing operation on a flexible filament semiconductor, there are dispensing abnormalities, resulting in subsequent inability to solder wires normally, or problems with the bonding between the LED chips and the bottom film.

[0015] In summary, in view of the deficiencies and defects of the prior art, how to improve the above problems is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Utility Model

[0016] It should be noted in particular that the present disclosure may actually include one or more technical solutions that are currently claimed or not yet claimed. And in the process of writing the specification, in order to avoid confusion caused by unnecessary distinction between these technical solutions, multiple possible technical solutions herein may be collectively referred to as "the present application" herein.

[0017] Many embodiments of "this application" are generally described herein. However, the term "this application" is only used to describe certain embodiments disclosed in this specification (whether in the claims or not), and is not a complete description of all possible embodiments. Certain embodiments of the various features or aspects described below as "this application" may be combined in different ways to form an LED bulb or a part thereof.

[0018] In one embodiment of this application, an LED filament is provided, which is characterized in that the LED filament includes: an LED chip, a light conversion layer, a laminate, and electrodes, and the adjacent LED chips, the LED chip and the electrodes are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrodes, the laminate is disposed on the outer surface of the light conversion layer, and the laminate covers at least a part of the surface of the light conversion layer, wherein the laminate includes a colorant.

[0019] In one embodiment of this application, when the LED filament is lit, the surface of the LED filament lamp is white, gray, black, blue, green, purple and other colors.

[0020] In one embodiment of this application, the hardness of the laminate is less than that of the light conversion layer.

[0021] In one embodiment of this application, the hardness of the laminate is greater than that of the light conversion layer.

[0022] In one embodiment of this application, the laminate includes a photoreactive substance. After the LED chip emits light, it undergoes a first light conversion through the light conversion layer, and then undergoes a second light conversion through the photoreactive substance in the laminate.

[0023] In one embodiment of this application, the LED filament has a first color when not lit and a second color different from the first color when lit.

[0024] In one embodiment of this application, the laminate is made of silicone or a material with silicone as the main body. When directly using silicone, the laminate is white due to the color of the silicone itself.

[0025] In one embodiment of this application, the LED filament has a bendable section and a non-bendable section in the length direction, and the total length of the bendable section is less than the total length of the non-bendable section.

[0026] In one embodiment of this application, the non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

[0027] In one embodiment of this application, the bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

[0028] In one embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0029] In one embodiment of the present application, adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0030] In one embodiment of the present application, there are an LED chip, a light conversion layer, a layer-like body and an electrode. Adjacent LED chips, and the LED chip and the electrode are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrode. The light conversion layer includes a top layer and a carrier layer, and the color of the upper surface of the top layer is different from that of the lower surface of the carrier layer. When the LED filament is not lit, it presents two different colors.

[0031] In one embodiment of the present application, the length direction of the LED filament has a bendable section and a non-bendable section, and the total length of the bendable section is less than the total length of the non-bendable section.

[0032] In one embodiment of the present application, the non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

[0033] In one embodiment of the present application, the bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

[0034] In one embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0035] In one embodiment of the present application, adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0036] In one embodiment of the present application, there is provided an LED bulb lamp, which is characterized by comprising: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column and an LED filament. The LED filament includes an LED chip, a light conversion layer, a layer-like body and an electrode. Adjacent LED chips, and the LED chip and the electrode are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrode. The layer-like body is arranged on the outer surface of the light conversion layer, and the layer-like body covers at least a part of the surface of the light conversion layer. Among them, the layer-like body includes a colorant, and the surface of the LED filament presents white when not lit.

[0037] In one embodiment of the present application, the hardness of the layer-like body is less than that of the light conversion layer.

[0038] In one embodiment of the present application, the hardness of the laminate is greater than that of the light conversion layer.

[0039] In one embodiment of the present application, the laminate includes a photoreactive substance. After the LED chip emits light, it undergoes a first light conversion through the light conversion layer and a second light conversion through the photoreactive substance in the laminate.

[0040] In one embodiment of the present application, the LED filament has a first color when not lit and a second color different from the first color when lit.

[0041] In one embodiment of the present application, the laminate is made of silicone or a material with silicone as the main body. When directly using silicone, the laminate is white due to the color of the silicone itself.

[0042] In one embodiment of the present application, the LED filament has a bendable section and a non-bendable section in the length direction, and the total length of the bendable section is less than the total length of the non-bendable section.

[0043] In one embodiment of the present application, the non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

[0044] In one embodiment of the present application, the bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

[0045] In one embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0046] In one embodiment of the present application, the adjacent LED chips are staggered in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0047] In one embodiment of the present application, there is provided an LED bulb, which is characterized by including: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column, and an LED filament. The LED filament includes an LED chip, a light conversion layer, a laminate, and an electrode. The adjacent LED chips and the LED chip and the electrode are electrically connected to each other. The light conversion layer wraps the LED chip and at least a part of the electrode. The light conversion layer includes a top layer and a carrier layer, and the upper surface of the top layer and the lower surface of the carrier layer have different colors. The LED filament presents two different colors when not lit.

[0048] In one embodiment of the present application, the LED filament has a bendable section and a non-bendable section in the length direction, and the total length of the bendable section is less than the total length of the non-bendable section.

[0049] In an embodiment of the present application, the non-bendable section is the part including the LED chip or electrode in the length direction of the LED filament.

[0050] In an embodiment of the present application, the bendable section is the part including only the light conversion layer or the wire in the length direction of the filament.

[0051] In an embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0052] In an embodiment of the present application, the adjacent LED chips are staggered in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0053] The present application provides an LED bulb lamp, which is characterized by including: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column and an LED filament. The LED filament includes an LED chip, a light conversion layer, a layer-like body and an electrode. The adjacent LED chips, the LED chip and the electrode are electrically connected to each other. The light conversion layer wraps the LED chip and at least a part of the electrode. The layer-like body is arranged on the outer surface of the light conversion layer, and the layer-like body covers at least a part of the surface of the light conversion layer. Wherein, the layer-like body includes a colorant, and the surface of the LED filament presents gray when not lit.

[0054] In an embodiment of the present application, the hardness of the layer-like body is less than that of the light conversion layer.

[0055] In an embodiment of the present application, the hardness of the layer-like body is greater than that of the light conversion layer.

[0056] In an embodiment of the present application, the layer-like body includes a light-reactive substance. After the LED chip emits light, it undergoes the first light conversion through the light conversion layer, and then undergoes the second light conversion through the light-reactive substance in the layer-like body.

[0057] In an embodiment of the present application, the LED filament has a first color when not lit and a second color different from the first color when lit.

[0058] In an embodiment of the present application, the layer-like body adopts a material with silicone or silicone as the main body. When directly using silicone, the layer-like body presents white due to the color of the silicone itself.

[0059] In an embodiment of the present application, the length direction of the LED filament has a bendable section and a non-bendable section, and the total length of the bendable section is less than the total length of the non-bendable section.

[0060] In one embodiment of the present application, the non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

[0061] In one embodiment of the present application, the bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

[0062] In one embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0063] In one embodiment of the present application, the adjacent LED chips are staggered in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0064] The present application provides an LED bulb, which is characterized by comprising: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column and an LED filament. The LED filament includes an LED chip, a light conversion layer, a layer-like body and an electrode. The adjacent LED chips, the LED chip and the electrode are electrically connected to each other. The light conversion layer wraps the LED chip and at least a part of the electrode. The light conversion layer includes a top layer and a bearing layer. The upper surface of the top layer and the lower surface of the bearing layer have different colors. The LED filament presents two different colors when not lit.

[0065] In one embodiment of the present application, the length direction of the LED filament has a bendable section and a non-bendable section, and the total length of the bendable section is less than the total length of the non-bendable section.

[0066] In one embodiment of the present application, the non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

[0067] In one embodiment of the present application, the bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

[0068] In one embodiment of the present application, there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

[0069] In one embodiment of the present application, the adjacent LED chips are staggered in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

[0070] Through the above technical solutions, this application has the following technical effects, either alone or in any combination: (1) By filling a combination of nitrogen and oxygen into the lamp housing, due to the interaction between oxygen and the groups in the base layer, the service life of the base layer can be effectively improved; (2) By designing the relationship between the diameter of the lamp head, the maximum diameter of the lamp housing, and the maximum width of the LED filament in the Y-axis direction on the YZ plane or the maximum width in the X-axis direction on the XZ plane, the heat dissipation effect of the bulb lamp can be effectively improved; (3) The thickness of the base layer is less than that of the top layer. Since the thermal conductivity of the top layer is greater than that of the base layer, and the heat conduction path of the heat generated by the LED chip to the outer surface of the base layer is relatively short, heat is not easily accumulated, and the heat dissipation effect of the LED filament is good; (4) The bearing layer includes a transparent layer and a base layer. The transparent layer supports a part of the base layer, thereby enhancing the strength of the base layer, facilitating die bonding and wire bonding. The part of the base layer not covered by the transparent layer allows the heat generated by a part of the LED chips to be directly dissipated after passing through the base layer; (5) The transparent layer includes a first transparent layer and a second transparent layer. When the LED filament is bent, it is easy for the part near the electrode to be separated from the light conversion layer or for cracks to appear in the part where the light conversion layer contacts the electrode. The first transparent layer and the second transparent layer can strengthen the structure of the part where the light conversion layer contacts the electrode, preventing cracks from appearing in the contact part of the light conversion layer and the electrode; (6) The conductor includes a covering part and an exposed part. When the LED filament is bent, the exposed part will be slightly deformed under force, with a small bending area and a small degree of deformation, which is beneficial to maintaining the bent shape of the LED filament. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1A is a schematic structural diagram of another embodiment of the LED filament of this application;

[0072] Figure 1B is a schematic structural diagram of another embodiment of the LED filament of this application;

[0073] Figure 1C is a schematic structural diagram of another embodiment of the LED filament of this application;

[0074] Figures 1D to 1G Schematic structural diagrams of multiple embodiments of the LED filament of this application are shown;

[0075] Figure 1H is a top view of an embodiment of the LED filament of this application after removing the top layer;

[0076] Figure 1I is a schematic structural diagram of another embodiment of the LED filament of this application;

[0077] Figure 1J is a schematic structural diagram of another embodiment of the LED filament of this application;

[0078] Figure 1KIt is a schematic structural diagram of wire bonding for an LED chip in an embodiment;

[0079] Figure 1L It is a top view of an embodiment after removing the top layer in the unbent state of an LED filament in an embodiment of the present application;

[0080] Figure 1M It is a top view of an embodiment after removing the top layer in the unbent state of an LED filament in an embodiment of the present application;

[0081] Figure 1N It is a schematic structural diagram of an LED filament in the unbent state in an embodiment of the present application;

[0082] Figure 1O It is a schematic structural diagram of an LED filament in the unbent state in some embodiments of the present application;

[0083] Figure 1P It is a schematic structural diagram of a part of an LED filament in an embodiment of the present application;

[0084] Figure 1Q It is Figure 1P The cross-sectional structural diagram of;

[0085] Figure 1R It is a schematic structural diagram of a part of an LED filament in an embodiment of the present application;

[0086] Figure 1S It is a schematic structural diagram of a part of an LED filament in an embodiment of the present application;

[0087] Figure 1T It is a schematic structural diagram of an LED filament in the unbent state in an embodiment of the present application;

[0088] Figure 1U It is a schematic structural diagram of an LED filament in the unbent state in some embodiments of the present application;

[0089] Figure 1V It is a schematic structural diagram of an LED filament in the unbent state in some embodiments of the present application;

[0090] Figure 1W It is a schematic structural diagram of an LED filament in the unbent state in some embodiments of the present application;

[0091] Figure 2A It is a schematic structural diagram of an embodiment of the LED filament of the present application;

[0092] Figure 2B It is Figure 2A The bottom view of;

[0093] Figure 2C It is Figure 2APartial sectional view schematic diagram at position A-A;

[0094] Figures 3A to 3E Schematic diagram of the first embodiment of the manufacturing method of the LED filament of the present application;

[0095] Figures 4A to 4D Schematic diagram, side view, another side view and top view of an LED bulb lamp according to an embodiment of the present application are shown respectively;

[0096] Figure 5 Schematic diagram of an LED bulb lamp according to an embodiment of the present application;

[0097] Figure 6A Schematic diagram of a lamp cap according to an embodiment of the present application;

[0098] Figure 6B Is Figure 6A Schematic diagram of the A-A cross-section;

[0099] Figure 7A Schematic diagram of a lamp cap according to an embodiment of the present application;

[0100] Figure 7B Is Figure 7A Schematic diagram of an embodiment of the B-B cross-section;

[0101] Figure 7C Is Figure 7A Schematic diagram of an embodiment of the B-B cross-section;

[0102] Figures 8A to 8D Schematic diagram, side view, another side view and top view of an LED bulb lamp according to an embodiment of the present application are shown respectively;

[0103] Figures 9A to 9D Schematic diagram, side view, another side view and top view of an LED bulb lamp according to an embodiment of the present application are shown respectively;

[0104] Figure 10A Schematic diagram when the LED filament is not bent in an embodiment;

[0105] Figure 10B For application Figure 10A Schematic diagram of an LED bulb lamp using the shown LED filament;

[0106] Figure 11A Schematic diagram of an LED bulb lamp in an embodiment;

[0107] Figure 11B Is Figure 11A Enlarged schematic diagram of part A;

[0108] Figure 12The figure shows the schematic diagram of the light-emitting spectrum of the LED bulb lamp according to an embodiment of the present application;

[0109] Figure 13 The figure shows the schematic diagram of the light-emitting spectrum of the LED bulb lamp according to an embodiment of the present application;

[0110] Figure 14 The figure shows the schematic diagram of the light-emitting spectrum of the LED bulb lamp according to an embodiment of the present application;

[0111] Figure 15 It is the schematic diagram of the light transmission of the LED bulb lamp of the present application;

[0112] Figure 16 The schematic diagrams of the C0 / 180 plane and the C90 / 270 plane of the LED bulb lamp of the present application;

[0113] Figure 17 It is the light distribution curve graph of the LED bulb lamp according to an embodiment;

[0114] Figure 18 It is the light distribution curve graph of the LED bulb lamp according to an embodiment;

[0115] Figure 19 It is the light distribution curve graph of the LED bulb lamp according to an embodiment;

[0116] Figure 20 It is the light distribution curve graph of the LED bulb lamp according to an embodiment;

[0117] Figure 21 It is the circuit diagram of the first constant current circuit according to the embodiment of the present utility model;

[0118] Figure 22 It is the circuit diagram of the second constant current circuit according to the embodiment of the present utility model;

[0119] Figure 23 It is the circuit diagram of the third constant current circuit according to the embodiment of the present utility model;

[0120] Figure 24 It is the schematic diagram of the circuit block of the LED lamp according to an embodiment of the present application;

[0121] Figure 25A It is the schematic diagram of the circuit structure of the LED lamp according to an embodiment of the present application;

[0122] Figure 25B It is the schematic diagram of the circuit structure of the LED lamp according to another embodiment of the present application;

[0123] Figure 25C It is the schematic diagram of the circuit structure of the LED lamp according to yet another embodiment of the present application;

[0124] In the figure:

[0125] R1 to R4 are the first to fourth resistors respectively; M1 is the main switching element, and Q1 is the auxiliary switching element, and switching devices such as field effect transistors and triodes can be used; D5 is a light emitting diode or a group of light emitting diodes; PTC is a PTC resistor; V2 is a voltage source. Detailed implementation manners

[0126] To make the above objects, features and advantages of the present application more obvious and understandable, the following will describe in detail the specific embodiments of the present application with reference to the accompanying drawings.

[0127] Such as Figures 1A to 1M 、 Figures 2A to 2C And Figures 3A to 3EAs shown, the LED filament has a light conversion layer 220 / 420, an LED chip unit 202 / 204 (or an LED segment 402 / 404), and electrodes (or conductive electrodes) 210, 212 / 410, 412. The light conversion layer 220 / 420 wraps the LED chip unit 202 / 204 (or the LED segment 402 / 404) and part of the electrodes (or conductive electrodes) 210, 212 / 410, 412, and a part of the electrodes (or conductive electrodes) 210, 212 / 410, 412 are exposed outside the light conversion layer 220 / 420. The adjacent LED chip units 202, 204 (or LED segments 402, 404) and between the LED chip unit 202 / 204 (or LED segment 402 / 404) and the electrodes (or conductive electrodes) 210, 212 / 410, 412 are electrically connected to each other. The LED filament includes at least two LED chips 442, and the adjacent LED chips 442 are electrically connected to each other. The LED chip unit 202 / 204 (or LED segment 402 / 404) includes at least one LED chip 442. The light conversion layer 420 includes a top layer 420a and a carrier layer, and the top layer 420a and the carrier layer can each be a layered structure of at least one layer. The layered structure can be selected from: a phosphor glue with high plasticity (relative to the phosphor film), a phosphor film with low plasticity, or a transparent layer, or any combination of the three. The phosphor glue / phosphor film contains the following components: silicone-modified polyimide and / or glue, and the phosphor glue / phosphor film can also include phosphors, inorganic oxide nanoparticles (or heat dissipation particles). The transparent layer 420c can be composed of a light-transmitting resin (such as silica gel, polyimide) or a combination thereof. The glue can be, but is not limited to, silica gel. In one embodiment, the materials of the top layer 420a and the carrier layer are the same. In one embodiment, the carrier layer includes a base layer 420b. In the height direction of the LED filament, the height of the top layer 420a is greater than the height of the base layer 420b. The base layer 420b includes an upper surface and a lower surface that are opposite to each other, the top layer 420a includes an upper surface and a lower surface that are opposite to each other, and the upper surface of the base layer 420b is in contact with a part of the lower surface of the top layer 420a; the LED chip 442 includes an upper surface and a lower surface that are opposite to each other, the upper surface of the LED chip 442 is closer to the upper surface of the top layer 420b than the lower surface of the LED chip 442, and the distance from the lower surface of the LED chip 442 to the lower surface of the base layer 420b is less than the distance from the lower surface of the LED chip 442 to the upper surface of the top layer 420a. Since the thermal conductivity of the top layer 420a is greater than the thermal conductivity of the base layer 420b, and the heat generated by the LED chip 442 is conducted to the outer surface of the base layer 420b over a relatively short distance, heat is not easily accumulated, and the heat dissipation effect of the LED filament is good. In one embodiment, if the electrical energy supplied to the LED filament does not exceed 8w, when the LED filament is lit, at least 4lm of luminous flux is emitted per millimeter of the length of the LED filament (or per millimeter of the length of the filament body or per millimeter of the length of the top layer 420a).In one embodiment, the average length of the LED filament per millimeter (or the average length of the filament body per millimeter or the average length of the top layer 420a per millimeter) includes at least two LED chips 442. In a surrounding environment of 25 °C, the junction temperature of the LED chip 442 is not greater than the junction temperature of the LED chip 442 when the LED filament is lit for 15,000 hours. Or if the electrical energy supplied to the LED filament does not exceed 8 W, when the LED filament is lit, the average luminous flux emitted per cubic millimeter of the LED filament volume (or the average volume of the filament body per cubic millimeter or the average volume of the top layer 420a per cubic millimeter) is at least 4 lm. In one embodiment, the average volume of the LED filament per cubic millimeter (or the average volume of the filament body per cubic millimeter or the average volume of the top layer 420a per cubic millimeter) includes at least two LED chips. In a surrounding environment of 25 °C, the junction temperature of the LED chip 442 is not greater than the junction temperature of the LED chip 442 after the LED filament is lit for 15,000 hours. In some embodiments, the lifespan of the LED chip 442 can be related to the thermal equilibrium temperature (such as the junction temperature of the LED chip 442). The relationship between the lifespan of the LED chip 442 and the junction temperature varies depending on the manufacturer of the LED chip 442. In the LED filament, the heat of the LED chip 442 is transferred to the surrounding environment by heat conduction, and the temperature is maintained not higher than a specific temperature (for example, maintaining the junction temperature of the LED chip not higher than the junction temperature of the LED chip with a 15,000-hour rated lifespan in a 25 °C surrounding environment).

[0128] In most application scenarios, the filament lamp product is no longer solely for lighting purposes, but has become an integral part of environmental decoration. That is, when the filament lamp is not lit, consumers are concerned about the filament shape and appearance color (including the appearance color of the filament (or the color of the filament body) and the appearance color of the bulb); when the filament lamp is lit, the focus is on the color temperature performance and whether the illuminance meets the environmental requirements. The above-mentioned filament body does not include the part where the electrode exposes the light conversion layer 420. In one embodiment, when the LED filament is not lit, the surface of the LED filament is white, gray, black, blue, green, purple and other colors. In some embodiments, the surface of the LED filament can be the surface of the light conversion layer 420. After the LED filament is lit, it can emit light of a different color from when the LED filament is not lit, so that the bulb lamp with this LED filament can be applied in different scenarios to achieve different decorative effects. In some embodiments, the LED filament includes a coating, and the color of the coating is white, gray, black, blue, green, purple and other colors. The coating covers at least a part of the surface of the light conversion layer 420, and preferably the coating covers the entire surface of the light conversion layer 420. For example, when the surface of the light conversion layer 420 is coated with a red coating, when the LED filament is not lit, the surface of the LED filament is red, and when the LED filament is lit, the LED filament emits white light. Of course, the LED filament can emit light of the same color as when the LED filament is not lit. For example, when the surface of the light conversion layer 420 is coated with a white coating, when the LED filament is not lit, the surface of the LED filament is white, and when the LED filament is lit, the light emitted by the LED filament is also white. The white coating can be alumina. In some embodiments, the surface of the top layer 420a and / or the carrier layer is covered with a thin film, and the color of the thin film is black, gray, red and other colors. Generally, substances have a certain light absorption property. It is preferred to use a thin film with a high light transmittance. For example, the light transmittance of the thin film is at least greater than 80, which can prevent the light flux from decreasing after the LED filament is lit. In some embodiments, the thickness of the thin film is less than the thickness of the top layer 420a, and the heat generated by the LED chip 442 is not easily accumulated in the thin film, taking into account the requirements of the appearance and heat dissipation of the LED filament. The thin film can contain phosphor or not. When the thin film contains phosphor, the phosphor content of the thin film is less than the phosphor concentration of the top layer 420a or the carrier layer. If the top layer 420a or the carrier layer is a multi-layer structure, the phosphor content of the thin film is at least less than the phosphor content of one of the layers. Due to the presence of the thin film, the thickness of the LED filament increases, and the heat conduction path of the LED filament becomes longer. If the phosphor content in the thin film is increased to improve the heat dissipation performance of the LED filament, the hardness of the thin film will increase due to the increase in the phosphor content in the thin film, resulting in a worse flexibility of the LED filament and an increased probability of cracks when the LED filament is bent. Therefore, in this application, a certain amount of phosphor is added to the thin film, which can change the color of the LED filament when it is not lit while taking into account the heat dissipation performance and flexibility of the LED filament.In some embodiments, after the top layer 420a and / or the base surface are covered with a thin film, when the filament is not lit, the color of the filament body is grayish black (close to the original color of the tungsten wire), and when the LED filament is lit, the light emitted by the LED filament is white. In some embodiments, the colors of the light conversion layer, the filament body, etc. when the filament is not lit or the color of the light emitted by the LED filament after it is lit include primary colors and colors formulated from at least two primary colors. For example, the primary colors are the three primary colors of light (RGB).

[0129] As Figure 1W shown, the above-mentioned coating or thin film is a layered body 480 provided on the outer surface of the light conversion layer 420. In some embodiments, the hardness of the layered body 480 is less than that of the light conversion layer 420 to prevent the layered body 480 from being too hard and thus affecting the normal bending of the filament. In some embodiments, the hardness of the layered body 480 can be greater than that of the light conversion layer 420 to play a further supporting role for the entire filament. Regardless of the hardness of the layered body 480, through the setting of the layered body 480, the overall support of the filament can be improved.

[0130] The bulb of the filament lamp is filled with gas, and the refractive indices of the light conversion layer 420, the layered body 480, and the filling gas in the bulb decrease in sequence. Compared with not setting the layered body, due to the large difference in refractive index between the light conversion layer and the filling gas, relatively large light loss may be caused. However, in this embodiment, through the above setting of the layered body 480, the LED chip 442 can have relatively small light loss in the light output path.

[0131] The layered body 480 can be made of silica gel or a material with silica gel as the main body. When directly using silica gel, the layered body 480 can be made to appear white through the color of the silica gel itself, so that the appearance of the filament appears white. After adding a colorant to the silica gel, the layered body 480 can be made to present different colors as described above. In addition, a photoreactive substance can also be added to the layered body 480, so that after the LED chip emits light and undergoes the first light conversion through the light conversion layer 420, it then passes through the photoreactive substance in the layered body 480 for the second light conversion, thereby realizing that when the LED filament is not lit, it has a first color, and after being lit, it has a second color different from the first color, and there is a difference in primary colors between the first color and the second color.

[0132] In one embodiment, the light conversion layer 420 includes a top layer 420a and a carrier layer. The top layer 420a and the carrier layer can each be a layered structure of at least one layer, and the color of the upper surface of the top layer 420a is different from that of the lower surface of the carrier layer. Since the LED filament presents two different colors when not lit, it can be applied to multi-color system usage scenarios.

[0133] In some embodiments, when there is only one column of LED chips 442 in the width direction of the LED filament (as Figure 2B shown, the LED chip 442 (i.e.,Figure 2B are arranged in the same direction), with a bendable section and a non-bendable section in the length direction of the LED filament, and the total length of the bendable section is less than the total length of the non-bendable section, so that the whole LED filament has better support. Among them, the non-bendable section is the total length of the part including the LED chip 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament, and the bendable section only includes the light conversion layer 220 / 420 and / or the wire (the wire here refers to the wire connecting adjacent LED chips or the wire connecting the LED chip and the electrode), that is, the part without the LED chip 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament forms the bendable section.

[0134] In some embodiments, in the length direction of the LED filament, the total length of the bendable section accounts for at least 30% or more of the total length of the LED filament to ensure the bendability of the filament.

[0135] In some embodiments, in the length direction of the LED filament, the total length of the bendable section accounts for at least 30% or more of the total length of the LED filament and does not exceed 50%, so that the LED filament has both bendability and support.

[0136] In some embodiments, when there are two columns of LED chips 442 in the width direction of the LED filament and these two columns of LED chips 442 are connected in parallel (as Figure 1L shown), similarly, there is a bendable section and a non-bendable section in the length direction of the LED filament, and the total length of the bendable section is less than the total length of the non-bendable section, so that the whole LED filament has better support and bendability. Among them, the non-bendable section is the total length of the part including the LED chip 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament, and the bendable section only includes the light conversion layer 220 / 420 and / or the wire (the wire here refers to the wire connecting adjacent LED chips or the wire connecting the LED chip and the electrode), that is, the part without the LED chip 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament forms the bendable section.

[0137] In some embodiments, the total length of the bendable section accounts for at least 0.001% or more of the total length of the LED filament and does not exceed 20%. In some embodiments, the part with LED chips arranged in the length direction of the LED filament (i.e., the area between the leftmost LED chip and the rightmost LED chip in Figure 1L may not have a bendable section. Since the adjacent LED chips are arranged staggeredly, it still has a certain degree of bendability.

[0138] In some embodiments, when there are two columns of LED chips 442 in the width direction of the LED filament, and these two columns of LED chips 442 are connected in series in sequence (as Figure 1M shown), there are bendable segments and non-bendable segments in the length direction of the LED filament, and the total length of the bendable segments is less than the total length of the non-bendable segments, so that the whole LED filament has better support. Among them, the non-bendable segment is the total length of the part including the LED chips 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament, and the bendable segment only includes the light conversion layer 220 / 420 and / or the wire (the wire here refers to the wire connecting adjacent LED chips or the wire connecting the LED chip and the electrode), that is, the part without the LED chips 442 or the electrodes 210, 212 / 410, 412 in the length direction of the LED filament forms the bendable segment.

[0139] In some embodiments, in the length direction of the LED filament, the total length of the bendable segments accounts for at least more than 0.001% and no more than 30% of the total length of the LED filament, so that the LED filament has both bendability and support.

[0140] In some embodiments, whether there is one column or two columns of LED chips on the LED filament, more than 0.5 LED chips are arranged per unit length (per millimeter length) so that a reasonable spacing can be set between the LED chips to meet the requirement of light emission uniformity and prevent serious thermal influence between the LED chips.

[0141] Figure 1A is a schematic structural diagram of an embodiment of the LED filament of the present application. The LED filament 400 has: a light conversion layer 420; LED segments 402 / 404 and electrodes 410 / 412. The LED segments 402 / 404 have at least one LED chip 442. The adjacent LED chips in the LED filament and the LED chip and the electrodes 410 / 412 are electrically connected to each other. For example, it can be through a circuit film, as described later, for example Figure 1BThe above electrical connection is achieved in the manner of the first wire 440, etc. The light conversion layer 420 includes a top layer 420a and a carrier layer. The carrier layer includes a base layer 420b and a transparent layer 420c. The base layer 420b is located between the top layer 420a and the transparent layer 420c (at least on a certain cross-section of the LED filament 400). In one embodiment, the base layer 420b includes an upper surface and a lower surface that are opposite to each other. The upper surface of the base layer 420b is in contact with a part of the top layer 420a, and the lower surface of the base layer 420b is in contact with the transparent layer 420c. In some embodiments, the lower surface of a part of the base layer 420b is in contact with the transparent layer 420c. The transparent layer 420c supports a part of the base layer 420b, thereby enhancing the strength of the base layer 420b and facilitating die bonding and wire bonding. The part of the base layer 420b not covered by the transparent layer 420c allows the heat generated by a part of the LED chips 442 to be directly dissipated after passing through the base layer 420b. In this embodiment, the total length of the base layer 420b is the same as the total length of the top layer 420a. In one embodiment, the total length of the transparent layer 420c is 5-100% of the total length of the base layer 420b. In one embodiment, the length of the transparent layer 420c is less than the length of the base layer 420b, and the total length of the transparent layer 420c is 10-80% of the total length of the base layer 420b. In one embodiment, the total length of the transparent layer 420c is 10-50% of the total length of the base layer 420b. When the LED filament is relatively thin (for example, the width of the LED filament ≤ 120 μm), the heat dissipation area of the LED chip is relatively reduced. Since the transparent layer is located below the base layer, on the one hand, it can reduce the deformation of the base layer caused by heat; on the other hand, it can assist in supporting the LED chip and facilitate die bonding and wire bonding. In one embodiment, the transparent layer 420c includes a first transparent layer 420c1 and a second transparent layer 420c2. Both the first transparent layer 420c1 and the second transparent layer 420c2 extend along the length direction of the LED filament. The first transparent layer 420c1 extends from one end of the base layer 420b, and the second transparent layer 420c2 extends from the other end of the base layer 420b. The extending direction of the first transparent layer 420c1 is opposite to the extending direction of the second transparent layer 420c2. In one embodiment, the light conversion layer 420 has a first end and a second end opposite to the first end. In one embodiment, the LED chip 442 is located between the first end and the second end. If the LED chip closest to the first end is denoted as LED chip n 1 , then the LED chips from the first end to the second end are LED chip n 2 , n 3 , ……n m, m is an integer and m ≤ 800. In some embodiments, 50 ≤ m ≤ 300. In the length direction of the LED filament, the lengths of the first transparent layer 420c1 and / or the second transparent layer 420c2 are at least greater than the distance from the first end to the LED chip n2. There is a gap between the first transparent layer 420c1 and the second transparent layer 420c2. In the length direction of the LED filament, the distance between the first transparent layer 420c1 and the second transparent layer 420c2 is greater than the length of the first transparent layer 420c1 and / or the second transparent layer 420c2. When the LED filament is bent, it is easy for the part near the electrode to be separated from the light conversion layer or for cracks to appear in the part where the light conversion layer contacts the electrode. The first transparent layer 420c1 and the second transparent layer 420c2 can structurally reinforce the part where the light conversion layer contacts the electrode, preventing cracks from appearing in the contact part between the light conversion layer 420 and the electrodes 410 / 412.

[0142] Figure 1B is a schematic structural diagram of another embodiment of the LED filament of the present application, as Figure 1B shown, the LED filament 400 has: a light conversion layer 420; LED segments 402, 404; electrodes 410, 412; and a conductor segment 430 for electrically connecting adjacent two LED segments 402, 404. The LED segment 402 / 404 includes at least two LED chips 442, and the LED chips 442 are electrically connected to each other through a first wire 440. In this embodiment, the conductor segment 430 includes a conductor 430a connecting the LED segments 402, 404. The shortest distance between two LED chips 442 located in adjacent two LED segments 402, 404 is greater than the distance between adjacent two LED chips within the LED segment 402 / 404, and the length of the first wire 440 is less than the length of the conductor 430a. In this way, it is ensured that when the two LED segments are bent, the stress generated does not cause the conductor segment to break. The light conversion layer 420 is coated on at least two sides of the LED chips 442 / electrodes 410, 412. The light conversion layer 420 exposes a part of the electrodes 410, 412. The light conversion layer 420 has a top layer 420a and a carrier layer, serving as the upper layer and the lower layer of the LED filament respectively. In this embodiment, the carrier layer includes a base layer 420b, and the base layer 420b includes an upper surface and a lower surface opposite to the upper surface. Relative to the lower surface of the base layer 420b, the upper surface of the base layer 420b is closer to the top layer 420a. The LED segments 402 / 404 and part of the electrodes 410 / 412 are placed on the upper surface of the base layer 420b, or at least one side of the LED segments 402 / 404 is in contact with the upper surface of the base layer 420b (direct contact or indirect contact).

[0143] as Figure 1CAs shown, in this embodiment, the conductor segment 430 is also located between two adjacent LED segments 402 and 404, and multiple LED chips 442 in the LED segments 402 and 404 are electrically connected to each other through the first wire 440. However, Figure 1C the conductor 430a in the conductor segment 430 is not in the form of a wire, but in the form of a sheet or film. In some embodiments, the conductor 430a can be copper foil, gold foil or other materials that can conduct electricity. In this embodiment, the conductor 430a is attached to the surface of the base layer 420b and adjacent to the top layer 420a, that is, between the base layer 420b and the top layer 420a. Moreover, the conductor segment 430 and the LED segments 402 / 404 are electrically connected through the second wire 450, that is, the two LED chips 442 that are respectively located in two adjacent LED segments 402 and 404 and have the shortest distance from the conductor segment 430 are electrically connected to the conductor 430a in the conductor segment 430 through the second wire 450. Among them, the length of the conductor segment 430 is greater than the distance between two adjacent LED chips 442 in the LED segments 402 and 404, and the length of the first wire 440 is less than the length of the conductor 430a. With this design, since the conductor segment has a relatively long length, good bendability of the conductor segment can be ensured. Assuming that the maximum thickness of the LED chip 442 in the radial direction of the LED filament is H, the thickness of the electrodes 410 / 412 and the conductor 430a in the radial direction of the LED filament is 0.5H to 1.4H, preferably 0.5H to 0.7H. There is a height difference between the LED chip and the electrode, and between the LED chip and the conductor, so that the wire bonding process can be implemented, and at the same time, the quality of the wire bonding process (that is, having good strength) can be ensured, and the stability of the product can be improved.

[0144] As Figure 1DAs shown, the LED filament 400 has: a light conversion layer 420; LED segments 402, 404; electrodes 410, 412; and a conductor segment 430 for electrically connecting adjacent two LED segments 402, 404. The LED segment 402 / 404 includes at least one LED chip 442. The conductor segment 430 and the LED segment 402 / 404 are electrically connected through a second wire 450, that is, the two LED chips 442 that are respectively located in adjacent two LED segments 402, 404 and are closest to the conductor segment 430 are electrically connected to the conductor 430a in the conductor segment 430 through the second wire 450. The LED chips 442 are electrically connected to each other through a first wire 440. The conductor segment 430 includes a conductor 430a connecting the LED segments 402, 404. The conductor 430a is, for example, a conductive metal sheet or metal strip, such as a copper sheet or an iron sheet. The shortest distance between two LED chips 442 respectively located in adjacent two LED segments 402, 404 is greater than the distance between adjacent two LED chips within the LED segment 402 / 404, and the length of the first wire 440 is less than the length of the conductor 430a. In this way, it is ensured that when the two LED segments are bent, the stress generated by the larger stress-bearing area of the conductor segment will not cause the conductor segment to break. The light conversion layer 420 covers at least two sides of the LED chip 442 / electrodes 410, 412. The light conversion layer 420 exposes a part of the electrodes 410, 412. The light conversion layer 420 includes a top layer 420a and a carrier layer. The carrier layer includes a base layer 420b and a transparent layer 420c. The base layer 420b is located between the top layer 420a and the transparent layer 420c. The base layer 420b and the top layer 420a cover at least two sides of the LED chip 442. The thermal conductivity of the transparent layer 420c is greater than that of the base layer 420b. The thickness of the base layer 420b in the radial direction of the LED filament is less than or equal to the thickness of the conductor 430a in the radial direction of the LED filament. When the LED filament is relatively thin (for example, the width of the LED filament ≤ 120 μm), the heat dissipation area of the LED chip is relatively reduced. By adopting the transparent layer, on the one hand, the deformation of the base layer caused by heat can be reduced, and on the other hand, it can assist in supporting the LED chip, which is beneficial for die bonding and wire bonding. The transparent layer 420c can be, for example, a hard substrate such as an alumina ceramic plate or a sapphire substrate, or a soft substrate with a high thermal conductivity (for example, the thermal conductivity ≥ 2.0 (W / (m·K))). The semi-transparent alumina ceramic plate or the transparent sapphire substrate is beneficial for the light emitted by the LED chip towards the transparent layer to transmit out, so as to realize the full-circumference light of the LED filament. In this embodiment, the top layer 420a, the base layer 420b, and the transparent layer 420c wrap the conductor 430a, on the one hand, reducing the influence of the external environment on the conductor, and on the other hand, increasing the bearing capacity when the conductor is electrically connected and improving the electrical connection stability when the conductor is bent.In some embodiments, the thickness of the base layer 420b in the height direction of the LED filament is less than or equal to the thickness of the conductor 430a in the height direction of the LED filament. The heat conduction path from the LED chip to the transparent layer is short, improving the heat dissipation effect of the LED filament. In other embodiments, the thickness of the transparent layer 420c in the height direction of the LED filament is greater than the thickness of the base layer 420b in the height direction of the LED filament. The heat conduction path from the LED chip to the transparent layer is short, improving the heat dissipation effect of the LED filament. In some implementations, the absolute value of the height difference between the LED chip 442 and the conductor 430a in the height direction of the LED filament is greater than the height of the LED chip 442 in the height direction of the LED filament. When the LED filament is bent, the second wire is less deformed after being stressed and extended, and the second wire is not easily broken. In some embodiments, the base layer 420b is in contact with at least one side of the LED chip 442 and one side of the conductor segment 430. In this embodiment, the LED chip 442 and the conductor 430a are located on different sides of the base layer 420b.

[0145] Please refer to Figures 1E to 1G , in some embodiments, the conductor 430a includes a covering portion 430b and an exposed portion 430c. The length of the exposed portion 430c in the axial direction of the LED filament is less than the distance between adjacent LED chips within any LED segment 402 / 404. When the LED filament is bent, the exposed portion 430c will be slightly deformed when stressed, with a small bending area and a small degree of deformation, which is beneficial to maintaining the bent shape of the LED filament. As Figure 1E shown, the exposed portion 430c includes a first exposed portion 430c1 and a second exposed portion 430c2. The portion of the top layer 420a that exposes the conductor 430a is the first exposed portion 430c1, and the portion of the transparent layer 420c that exposes the conductor 430a is the second exposed portion 430c2. The length of the first exposed portion 430c1 in the axial direction (length direction) of the LED filament is greater than or equal to the length of the second exposed portion 430c2 in the axial direction of the LED filament to ensure the stability of electrical connection and uniform stress when the conductor is bent. As Figure 1F shown, the exposed portion only includes the first exposed portion 430c1. The length of the first exposed portion 430c1 in the axial direction of the LED filament is less than or equal to the distance between adjacent LED chips within any LED segment 402 / 404. When the LED filament is bent, the stress generated during bending is concentrated on the conductor segment, reducing the risk of breakage of the wire connecting adjacent LED chips. As Figure 1G shown, the exposed portion only includes the second exposed portion 430c2, which can relieve the stress concentration of the conductor. The length of the second exposed portion 430c2 in the axial direction of the LED filament is less than or equal to the distance between adjacent LED chips within any LED segment 402 / 404. Since a part of the conductor is located between adjacent transparent layers, the stability of the support of the transparent layer for the conductor can be ensured.

[0146] Please refer to Figure 1H , the LED filament 400 has: a light conversion layer 420; LED segments 402, 404; electrodes 410, 412; and a conductor segment 430 for electrically connecting adjacent two LED segments 402, 404. The LED segments 402, 404 include at least one LED chip 442. The conductor segment 430 and the LED segments 402, 404 are electrically connected through a second wire 450, that is, the two LED chips 442 that are respectively located in adjacent two LED segments 402, 404 and are at the shortest distance from the conductor segment 430 are electrically connected to the conductor 430a in the conductor segment 430 through the second wire 450. The conductor segment 430 includes a conductor 430a connecting the LED segments 402, 404. The conductor 430a is, for example, a conductive metal sheet or metal strip, such as a copper sheet or an iron sheet. The shortest distance between two LED chips 442 respectively located in adjacent two LED segments 402, 404 is greater than the distance between adjacent two LED chips within the LED segment 402 / 404. The LED chips are electrically connected through a first wire 440, and the length of the first wire 440 is less than the length of the conductor 430a. When the two LED segments are bent, the stress generated by the larger force-bearing area of the conductor segment will not cause the conductor segment to break. The light conversion layer 420 covers at least two sides of the LED chip 442 / electrodes 410, 412. The light conversion layer 420 exposes a part of the electrodes 410, 412. The light conversion layer 420 includes a top layer (not shown in the figure) and a carrier layer. The carrier layer includes a base layer 420b and a transparent layer 420c. The LED chips 442 within the LED segment 402 / 404 are arranged along the radial direction of the LED filament (or the width direction of the LED filament). Each LED chip 442 within the LED segment 402 / 404 is respectively connected to the conductor 430a and / or the electrodes 410 / 412. In this embodiment, the widths of the base layer 420b and the transparent layer 420c in the radial direction of the LED filament are equal, and the contact area between the base layer 420b and the transparent layer 420c is large, so it is not easy for the base layer 420b and the transparent layer 420c to delaminate. In other embodiments, the width of the base layer 420b in the radial direction of the LED filament is less than the width of the transparent layer 420c in the radial direction of the LED filament. The top layer (not shown in the figure) is in contact with the base layer and the transparent layer 420c. The thickness of the base layer 420b is less than the thickness of the top layer. The heat dissipated by the LED chips is transferred to the top layer and the transparent layer through the base layer at the same time, thereby improving the heat dissipation efficiency of the LED filament. Secondly, the top layer and the transparent layer completely wrap the base layer, which can protect the base layer from the external environment. Moreover, when the LED filament is bent, due to the protection of multiple sides of the top layer, the probability of the second wire 450 breaking is reduced, and the product yield is improved.

[0147] Please refer to Figures 1I to 1J, the LED filament has: a light conversion layer 420; LED segments 402 / 404 and electrodes 410 / 412. The LED segments 402 / 404 have at least one LED chip 442, and the adjacent LED chips 442 in the LED filament and between the LED chips 442 and the electrodes 410 / 412 are electrically connected to each other. The adjacent LED chips 442 are connected by wires 440, and the light conversion layer 420 covers each surface of the wires 440, that is, the wires 440 are located in the light conversion layer 420, avoiding breakage due to accidental contact of the wires 440 by instruments or workers during the winding of the LED filament. The light conversion layer 420 wraps the LED segments 402 / 404 and the electrodes 410 / 412, and at least a part of two conductive electrodes 210 and 212 is exposed. The light conversion layer 420 includes a top layer 420a and a carrier layer, and the top layer 420a covers each surface of the wires 440, and there is a certain distance between the wires 440 and the carrier layer. The top layer 420a and the carrier layer can be respectively a layered structure of at least one layer. The top layer 420a includes a phosphor layer 420a1 and a phosphor film layer 420a2, or the top layer 420a includes a phosphor layer 420a1 and a phosphor glue layer 420a2. The thermal conductivity of the phosphor layer 420a1 is greater than that of the phosphor film layer (or phosphor glue layer) 420a2. The phosphor layer 420a1 is in contact with at least one surface of the LED chip 42. On the one hand, the heat generated by the LED chip 442 is directly transferred to the phosphor film layer / phosphor glue layer 420a2 through the phosphor layer 420a1. Since there is no non-thermally conductive or poorly thermally conductive silica gel in the phosphor layer 420a1, it has good thermal conductivity, and the heat generated by the LED chip 442 can be quickly transferred to the phosphor film layer / phosphor glue layer 420a2 through the phosphor layer 420a1, preventing heat from accumulating near the LED chip 442. The phosphor film layer or phosphor glue layer 420a2 is in contact with the phosphor layer 420a1; on the other hand, the light emitted by the LED chip 442 excites the phosphor layer 420a1 to generate a light of one color (such as red light), and the phosphor layer 420a1 has a weak absorption ability for the light emitted by the LED chip, so the light loss caused is small and does not affect the luminous flux of the LED bulb. The light emitted by the LED chip 442 is converted into white light after passing through the phosphor film layer or phosphor glue layer 420a2, and the light generated after exciting the phosphor layer 420a1 can supplement the white light with color light in a certain wavelength range (such as red light with a wavelength of 610nm - 650nm), so that the color rendering index (Ra) of the LED bulb is at least greater than 85 and / or R9 is greater than 45. After the LED bulb is lit, the color gamut of the lighting environment can be increased to improve the lighting environment quality.Furthermore, the phosphor layer 420a1 only covers the upper surface (or light-emitting surface) of the LED chip 442, or the phosphor layer 420a1 only contacts the upper surface (or light-emitting surface) of the LED chip 442. Since the light-emitting angle (or beam angle) of the LED chip 442 is generally 120 degrees and phosphors are generally relatively expensive, covering only the upper surface (or light-emitting surface) of the LED chip with the phosphor layer 420a1 can achieve the above-mentioned light-emitting effect and reduce the material cost of the LED bulb lamp.

[0148] In some embodiments, the phosphor layer 420a1 wraps a part of the wire 440, the phosphor film layer / phosphor glue layer 420a2 wraps another part of the wire 440, and the phosphor layer 420a1 and the phosphor film layer (or phosphor glue) 420a2 together cover the wire 440. The hardness of the phosphor layer 420a1 is greater than that of the phosphor film layer / phosphor glue layer 420a2, or the flexibility or bendability of the phosphor layer 420a1 is lower than that of the phosphor film layer / phosphor glue layer 420a2. The connection between the wire 440 and the LED chip 442 is wrapped by the phosphor layer 420a1, so the bendability at the connection between the wire 440 and the LED chip 442 can be reduced, and due to the protection of the phosphor layer 420a1, the risk of breakage at the connection between the wire 440 and the LED chip 442 can be further reduced. In addition, the phosphor layer 420a1 and the phosphor film layer / phosphor glue layer 420a2 can provide double protection for the wire 440 to prevent the wire from breaking when the LED filament is bent. The quality of the bonding wire is mainly determined by five points A, B, C, D, and E. A is the connection between the chip pad 4401 and the gold ball 4403, B is the connection between the gold ball 4403 and the wire 440, C is between the two segments of the wire 440, D is the connection between the wire 440 and the second solder pad 4402, and E is between the second solder pad 4402 and the surface of the chip 442. Since point B is the first bending point when the wire 440 bends, and the wire diameter of the wire 440 at point D is thinner, the wire 440 is likely to break at points B and D. Therefore, for example, when implementing a structure such as Figure 1K When the LED filament is bent, mainly the part of the wire 440 located in the phosphor film layer / phosphor glue layer 420a2 is stressed, while the part of the wire 440 located in the phosphor layer 420a1 is less stressed. Therefore, the thickness of the phosphor layer 420a1 can be less than the thickness of the phosphor film layer (or phosphor glue) 420a2. The phosphor layer 420a1 can cover points B and D of the wire. Due to the material properties (hardness, flexibility or bendability) of the phosphor layer 420a1, the wire can be prevented from breaking at points B and D.

[0149] Such as Figure 1IAs shown, a layer of phosphor layer 420a1 is respectively covered on each LED chip 442. In a part of the area of the LED filament, the phosphor film layer (or phosphor glue layer) 420a2 is in direct contact with the carrier layer. In some embodiments, this part of the area is located between two adjacent LED chips 442. The phosphor layer 420a1 only covers the LED chip 442, which can not only achieve the above-mentioned light-emitting effect but also reduce the production cost of the LED bulb lamp.

[0150] As Figure 1J shown, the phosphor layer 420a1 extends along the length direction of the LED filament. When coating the phosphor layer 420a1, it can be coated on a single LED filament or multiple LED filaments together. The coating process is simple and the production efficiency is high. In a part of the area of the LED filament, the phosphor layer 420a1 is in direct contact with the carrier layer. In some embodiments, this part of the area is located between two adjacent LED chips. Since the area of the phosphor layer 420a1 increases (the heat dissipation area also increases) and the phosphor layer 420a1 is relatively thin, the heat generated by the LED chip 442 is easily transferred from the phosphor layer 420a1 to the phosphor film layer (or phosphor glue layer) 420a2.

[0151] In some embodiments, the above-mentioned phosphor layer 420a1 includes phosphor and silica gel. The viscosity of the silica gel is not greater than 1600 mPa·s (under the conditions of 25°C and 10 rpm). The phosphor is easily mixed evenly with the silica gel, and the phosphor layer is relatively flat after coating. If the viscosity of the silica gel is greater than 1500 mPa·s (under the conditions of 25°C and 10 rpm), when preparing the phosphor layer 420a1, a diluent (such as kerosene) can be added. First, the silica gel is mixed with the diluent to reduce the viscosity, and then it is mixed with the phosphor. After the phosphor layer 420a1 is coated, the diluent is volatilized (such as by air drying and other means) to form the phosphor layer 420a1 on the surface of the LED chip 442. The phosphor can be a phosphor with a relatively narrow full width at half maximum (the full width at half maximum is not greater than 50 nm). The full width at half maximum is relatively narrow, the energy is strong, and the excitation efficiency is high. In order to supplement red light in general lighting devices, some phosphors with low peak wavelength ranges (the peak wavelength is not greater than 630 nm) and some phosphors with high peak wavelength ranges (the peak wavelength is greater than 640 nm) are used in combination. However, these phosphors generally have a relatively wide full width at half maximum and a relatively low excitation efficiency. After the lighting device is lit, the R9 value is relatively small and the color reproduction gamut is reduced. In one embodiment, a phosphor with a full width at half maximum (FWHM) of 10 - 30 nm and a peak wavelength of 630 - 635 nm can be used to supplement red light within a certain peak wavelength range, and the color reproduction gamut is increased.

[0152] Next, the chip wire bonding related design of the LED filament will be described. Figure 1LThe top view of the LED filament in the unbent state after removing the top layer in an embodiment of the present application. The LED filament includes a first LED chip unit 202, a second LED chip unit 204, and electrodes 210 / 212. The first LED chip unit 202 and the second LED chip unit 204 are electrically connected to the electrodes 210 / 212 respectively. The extending direction of the first LED chip unit 202 is parallel to or substantially parallel to the extending direction of the second LED chip unit 204, and the first LED chip unit 202 and the second LED chip unit 204 are connected in parallel. The first LED chip unit 202 and the second LED chip unit 204 each include a plurality of LED chips 442. The distance between two adjacent LED chips 442 in the first LED chip unit 202 is equal to the distance between two adjacent LED chips 442 in the second LED chip unit 204. In other embodiments, the distance between two adjacent LED chips 442 in the first LED chip unit 202 may not be equal to the distance between two adjacent LED chips 442 in the second LED chip unit 204. The light conversion layer 420 has a first end and a second end opposite to the first end. The LED chips 442 are located between the first end and the second end. The LED chip 442 closest to the first end in the first LED chip unit 202 is denoted as LED chip a1. Then, the LED chips 442 from the first end to the second end are LED chips a 2 , a 3 , …… a m , where m is an integer; the LED chip 442 closest to the first end in the second LED chip unit 204 is denoted as LED chip b1. Then, the LED chips 442 from the first end to the second end are LED chips b 2 , b 3 , …… b n , where n is an integer. In the length direction of the LED filament, LED chip b n is located between LED chip a m and LED chip a m+1 , and the projection of LED chip a m in the width direction of the LED filament coincides with LED chip b nThe projections in the width direction of the LED filaments do not have overlapping regions (n = m). That is to say, the LED chips 442 of the first LED chip unit 202 and the LED chips 442 in the second LED chip unit 204 are staggered in the length direction of the LED filament. With the same number of LED chips, the longer the length of the LED filament, the greater the distance between adjacent two LED chips; after the filament is lit, the light spots (or called granularity) observed by the naked eye will be more obvious, seriously affecting the viewing comfort of users; in addition, for the LED filaments of the same length, the more the number of LED chips, the smaller the distance between adjacent two LED chips, and the heat generated by adjacent LED chips will affect each other. To ensure that the LED filament has excellent light-emitting effect and heat dissipation performance, in this embodiment, the first LED chip unit 202 and the second LED chip unit 204 are connected in parallel, and the LED chips 442 in the second LED chip unit 204 are located between two adjacent LED chips 442 in the first LED chip unit 202. Since the light emitted by the second LED chip unit 204 can supplement the light spots generated by the first LED chip unit 202, the light-emitting effect of the LED filament is improved. In addition, compared with the LED filaments of the same LED filament length and the number of LED chips, the distance between two adjacent LED chips in the first LED chip unit 202 and the second LED chip unit 204 is larger, and the heat generated by adjacent LED chips is not easily affected by each other, and the junction temperature of the LED filament is reduced.

[0153] In another embodiment, the projections of the LED chips 442 in the first LED chip unit 202 and the LED chips 442 in the second LED chip unit 204 in the length direction of the LED filament have overlapping regions. LED chip a m and LED chip b n have overlapping regions in the projection in the length direction of the LED filament. Since in the width direction of the LED filament, the distance between LED chip a m and LED chip b n is reduced, the width of the LED filament becomes narrower, and the width of the LED filament is close to that of a traditional tungsten filament lamp, making the LED filament more beautiful when wound. Specifically, LED chip a m , LED chip b n each have multiple side surfaces. In the length direction of the LED filament, one side surface of LED chip b n is located between one side surface S m of LED chip a 1 and one side surface S m+1 of LED chip a 2 . In one embodiment, side surface S 1 is opposite to side surface S 2 . In one embodiment, in the width direction of the LED filament, LED chip am and the width of the LED chip b n are Wa and Wb respectively, and the width W of the LED filament is not less than the sum of Wa and Wb, that is, W≥Wa + Wb.

[0154] In an embodiment, the LED chip has a first light-emitting surface and a second light-emitting surface. The first light-emitting surface and the second light-emitting surface are opposite to each other. The light emitted from the first light-emitting surface (front surface) faces the top layer, and the light emitted from the second light-emitting surface (back surface) faces the carrier layer. The luminous flux of the light emitted from the front surface of the LED chip is equal to or approximately equal to the luminous flux of the light emitted from the back surface of the LED chip (the absolute value of the difference in luminous flux between the front and back surfaces ≤ 30 lm). The brightness difference between the front and back surfaces of the LED chip is small. The above LED chip is used in the LED filament, and the light is emitted evenly in all directions after the LED filament is wound. The LED bulb has an excellent light-emitting effect.

[0155] Figure 1M This is a top view of the LED filament in the unbent state of an embodiment of the present application after removing the top layer. The LED filament includes electrodes 210 / 212, LED chips 442, and wires 440. There are multiple LED chips 442, and the multiple LED chips 442 are arranged in two columns on the LED filament (that is, adjacent LED chips 442 are staggered in the width direction of the LED filament), and these two columns of LED chips 442 are arranged along the length direction of the LED filament respectively. The LED chips 442 are connected in series. The adjacent LED chips 442 in the length direction of the LED filament are connected by wires 440. Figure 1M Among them, the LED chip 442 closest to the electrode 210 in the length direction of the LED filament is electrically connected to the electrode 210 through a first conductive part 240. The LED chip 442 closest to the electrode 212 in the length direction of the LED filament is electrically connected to the electrode 210 through a first conductive part 240. The first conductive part 240 can be a wire.

[0156] In this embodiment, the LED chip 442 has a length dimension a along the length direction of the filament. The ratio of the sum of the lengths a of all the LED chips 442 (i.e., Σa) to the length of the LED filament is greater than 0.5, 0.6, 0.65 or 0.7, so as to ensure the setting density of the LED chips 442 in the length direction of the LED filament, thereby increasing the total luminous flux and effectively reducing the granularity of light emission. And because the adjacent LED chips 442 are staggered in the width direction of the LED filament, on the premise that the LED chips have the same spacing, it can have better bendability. On the contrary, when the ratio of the sum of the lengths of all the LED chips 442 to the length of the LED filament is greater than 0.5, 0.6, 0.65 or 0.7 and the LED chips 442 are arranged in a single row, it may lead to poor bendability of the LED filament, unable to be bent normally, which limits the shape of the filament.

[0157] Please continue to refer to Figures 2A to 2C , Figure 2A which is a schematic perspective partial cross-sectional view of an embodiment of the LED filament of the present application; Figure 2B is Figure 2A the bottom view schematic diagram of; Figure 2C is Figure 2A the partial cross-sectional view of the position A-A in. The LED filament 300 includes a plurality of LED chip units 202, 204, at least two conductive electrodes 210, 212, and a light conversion layer 220. The LED chip units 202, 204 are electrically connected to each other. The conductive electrodes 210, 212 are arranged corresponding to the LED chip units 202, 204, and electrically connect the LED chip units 202, 204 through a first conductive part 240. The light conversion layer 220 wraps the LED chip units 202, 204 and the conductive electrodes 210, 212, and at least exposes a part of the two conductive electrodes 210, 212. The light conversion layer 220 includes silica gel, phosphor and heat dissipation particles. In some embodiments, the LED chip unit 202 / 204 includes at least one LED chip, and the phosphor concentration corresponding to each surface of the LED chip is the same, so that the light conversion rate of each surface is the same, and the light uniformity of the LED filament is good.

[0158] The LED chip unit 202 / 204 includes at least one LED chip, and the LED chip unit 202 / 204 has a first electrical connection portion 206a and a second electrical connection portion 206b. In the length direction of the LED filament, the distance between the first connection portions 206a of two adjacent LED chip units 202, 204 is greater than the distance between two adjacent LED chip units 202, 204. In some embodiments, in the length direction of the LED filament, the distance between the first connection portion 206a and the second connection portion 206b of two adjacent LED chip units 202, 204 is greater than the distance between two adjacent LED chip units 202, 204, and at least a part of the first electrical connection portion 206a and the second electrical connection portion 206b is in contact with the light conversion layer 220. The first electrical connection portion 206a and the second electrical connection portion 206b are located on the same side of the LED chip unit 202 / 204.

[0159] In one embodiment, the second electrical connection portion 206b of the LED chip unit 202 is electrically connected to the first electrical connection portion 206a of the LED chip unit 204. For example, the second electrical connection portion 206b of the LED chip unit 202 can be electrically connected to the first electrical connection portion 206a of the LED chip unit 204 through the second conductive portion 260. The second conductive portion 260 has an end point a and an end point b, and the connection line of the end points a and b obtains a straight line ab, and the straight line ab intersects with the length direction p of the LED filament. In some embodiments, the light conversion layer 220 includes a top layer and a carrier layer (not shown in the figure). The top layer wraps the LED chip units 202 and 204 and the conductive electrodes 210 and 212, and at least a part of the two conductive electrodes 210 and 212 is exposed. The carrier layer includes a base layer, and the base layer includes an upper surface and a lower surface opposite to the upper surface. Relative to the lower surface of the base layer, the upper surface of the base layer is close to the top layer. At least one of the first conductive portion 240 and the second conductive portion 260 is in contact with (directly or indirectly) the upper surface of the base layer. When the LED filament is bent, the radius of curvature of the base layer after being bent by the force is relatively small, and the first conductive portion and the second conductive portion are not easily broken. In one embodiment, the first electrical connection portion 206a and the second electrical connection portion 206b are in contact with (directly or indirectly) the upper surface of the base layer. The LED chip unit can be a flip chip or a mini LED chip. Mini LED refers to an LED with a package size in the range of 0.1-0.2 mm, also known as a sub-millimeter light-emitting diode. When the LED chip units are electrically connected, for example, the second electrical connection portion 206b of the LED chip unit 202 can be a positive connection point, and the first electrical connection portion 206a of the LED chip unit 204 can be a negative connection point, and the second electrical connection portion 206b of the LED chip unit 202 is electrically connected to the first electrical connection portion 206a of the LED chip unit 204 through the second conductive portion 260. Or for another example, the second electrical connection portion 206b of the LED chip unit 202 can be a negative connection point, and the first electrical connection portion 206a of the LED chip unit 204 can be a positive connection point, and the second electrical connection portion 206b of the LED chip unit 202 is electrically connected to the first electrical connection portion 206a of the LED chip unit 204 through the second conductive portion 260. The first conductive portion 240 and the second conductive portion 260 can be in the form of wires or films, such as copper wires, gold wires, circuit films or copper foils, etc.

[0160] Please refer to Figures 3A to 3E , which is a schematic diagram of an embodiment of the manufacturing method of the LED filament of the present application. The manufacturing method of the LED filament includes:

[0161] S20: Lay the LED chip units 202 and 204 and the conductive electrodes 210 and 212 (as Figure 3A shown) on a carrier 280;

[0162] S22A: Coat the top layer 220a on the parts of the LED chip units 202, 204 and the conductive electrodes 210, 212 that do not contact the carrier 280. Then, perform a curing (or solidifying) process on the LED chip units 202, 204 and the conductive electrodes 210, 212 coated with the top layer 220a, so that the top layer 220a is cured and covers the LED chip units 202, 204 and the conductive electrodes 210, 212 above the carrier, and a part of at least two conductive electrodes 210, 212 is exposed (as Figure 3B shown). This curing process is, for example but not limited to, heating or ultraviolet (UV) irradiation;

[0163] S22B: There are several ways to flip the LED chip units 202, 204 and the conductive electrodes 210, 212 coated with the top layer 220a. One way is that the LED chip units 202, 204 and the conductive electrodes 210, 212 are only arranged on the carrier 280, and there is no adhesion relationship between them, so they can be directly flipped, and the flipped semi-finished product can be placed on the carrier 280 again.

[0164] Another way is that if there is a colloidal substance for adhesion between the carrier 280 and the LED chip units 202, 204, and the conductive electrodes 210, 212, such as photoresist used in the semiconductor process or die bonding glue that is easy to remove, after appropriate baking, this colloidal substance has the effect of temporarily fixing the LED chip units 202, 204, and the conductive electrodes 210, 212 on the carrier 280. Therefore, before or after flipping the LED chip units 202, 204, and the conductive electrodes 210, 212 coated with the top layer 220a, the photoresist coated on the carrier 280 can be washed with acetone, or the die bonding glue on the carrier can be removed with the corresponding solvent, so that the LED chip units 202, 204, and the conductive electrodes 210, 212 coated with the top layer 220a can be separated from the carrier 280. In addition, it can be further cleaned to remove the residual photoresist or die bonding glue.

[0165] S24: Electrically connect adjacent LED chip units 202, 204 and the LED chip units 202 / 204 and the conductive electrodes 210, 212 (as Figure 3C shown);

[0166] S26: After step S24, coat the base layer 220b on the parts of the LED chip units 202, 204 and the conductive electrodes 210, 212 that are not coated with the top layer 220a, and perform curing after coating (as Figure 3D shown).

[0167] Specifically, in order to increase the adhesion between the base layer 220b and the chip units 202 and 204, there may be die bonding glue. Further, in order to ensure that the chip units 202 and 204 can be stably attached to the base layer 220b, at least 80% of the bottom area where each chip unit 202 and 204 is attached to the base layer 220b is attached with die bonding glue. Further, 100% of the bottom area where each chip unit 202 and 204 is attached to the base layer 220b is attached with die bonding glue.

[0168] After step S26, there may further include step S28 of cutting the LED chip units 202 and 204 wrapped with the light conversion layer 220 and the conductive electrodes 210 and 212, that is, at the cutting positions drawn by the center dash line as shown in Figure 3E In this way, the cut strip-shaped component is the LED filament 300. The cutting method of step S28 is not limited to Figure 3E This is the limit, and every two adjacent vertical columns of LED chip units 202 and 204 can also be cut into a single LED filament.

[0169] In this embodiment, the top layer 220a and the base layer 220b in the method for preparing the LED filament may be made of the same proportion of phosphor and silica gel. If the top layer 220a and the base layer 220b also contain oxidized nanoparticles, the proportions of phosphor, silica gel, and oxidized nanoparticles in the top layer 220a and the base layer 220b are the same. In other words, the materials of the top layer 220a and the base layer 220b are the same substance, and they are only distinguished as the top layer 220a and the base layer 220b for the convenience of description. Of course, in other embodiments, the proportions of phosphor, silica gel, and oxidized nanoparticles in the top layer 220a and the base layer 220b may not be the same.

[0170] In one embodiment, the above-mentioned base layer includes silicone-modified polyimide, a thermosetting agent, heat dissipation particles, and phosphor. The thermosetting agent is epoxy resin, isocyanate, or bisoxazoline compound. The heat dissipation particles include silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), and zirconium oxide (ZrO 2 ), etc. In one embodiment, based on the weight of the silicone-modified polyimide, the dosage of the thermosetting agent is 3-12% of the weight of the silicone-modified polyimide. The silicone-modified polyimide includes repeating units represented by the following general formula (Ⅰ):

[0171]

[0172]

[0173] In the general formula (Ⅰ), Ar 1is a tetravalent organic group. The organic group has a benzene ring or an alicyclic hydrocarbon structure. The alicyclic hydrocarbon structure can be a monocyclic alicyclic hydrocarbon structure or can have an alicyclic hydrocarbon structure containing a bridged ring. As the alicyclic hydrocarbon structure containing a bridged ring, it can be a bicyclic alicyclic hydrocarbon structure or can be a tricyclic alicyclic hydrocarbon structure. The organic group can also be a benzene ring structure or an alicyclic hydrocarbon structure containing an active hydrogen functional group, and the active hydrogen functional group is any one or more of a hydroxyl group, an amino group, a carboxyl group, an amide group, or a mercapto group.

[0174] Ar 2 is a divalent organic group. The organic group can have, for example, a monocyclic alicyclic hydrocarbon structure or is a divalent organic group containing an active hydrogen functional group, and the active hydrogen functional group is any one or more than one of a hydroxyl group, an amino group, a carboxyl group, an amide group, or a mercapto group.

[0175] R is independently selected from a methyl group or a phenyl group.

[0176] n is from 1 to 5, and preferably n is 1 or 2 or 3 or 5.

[0177] The number-average molecular weight of the general formula (I) is from 5000 to 100000, preferably from 10000 to 60000, and more preferably from 20000 to 40000. The number-average molecular weight is the polystyrene conversion value based on the calibration curve prepared using standard polystyrene by a gel permeation chromatography (GPC) apparatus. When the number-average molecular weight is less than 5000, it is difficult to obtain good mechanical properties after curing, and in particular, the elongation rate tends to decrease. On the other hand, when it exceeds 100000, the viscosity becomes too high, making it difficult to form the resin.

[0178] Ar 1 is a component derived from a dianhydride. The dianhydride can include an aromatic dianhydride and an aliphatic dianhydride. The aromatic dianhydride includes an aromatic dianhydride containing only a benzene ring, a fluorinated aromatic dianhydride, an aromatic dianhydride containing an amide group, an aromatic dianhydride containing an ester group, an aromatic dianhydride containing an ether group, an aromatic dianhydride containing a sulfur group, an aromatic dianhydride containing a sulfone group, and an aromatic dianhydride containing a carbonyl group, etc.

[0179] Ar 2 is a component derived from a diamine. The diamine can be classified into an aromatic diamine and an aliphatic diamine. The aromatic diamine includes an aromatic diamine containing only a benzene ring structure, a fluorinated aromatic diamine, an aromatic diamine containing an ester group, an aromatic diamine containing an ether group, an aromatic diamine containing an amide group, an aromatic diamine containing a carbonyl group, an aromatic diamine containing a hydroxyl group, an aromatic diamine containing a carboxyl group, an aromatic diamine containing a sulfone group, an aromatic diamine containing a sulfur group, etc.

[0180] Adding different thermal curing agents will have different effects on the light transmittance of the silicone-modified polyimide.

[0181] Even when the same thermosetting agent is added, different addition amounts will have different effects on the light transmittance. Table 1-1 shows that when the addition amount of the thermosetting agent BPA in the fully aliphatic silicone-modified polyimide increases from 4% to 8%, the light transmittance increases. However, when the addition amount further increases to 12%, the performance of the light transmittance remains almost unchanged. It shows that the light transmittance will improve with the increase of the addition amount of the thermosetting agent, but when it is increased to a certain extent, adding more thermosetting agent has a rather limited effect on the light transmittance.

[0182] Table 1-1

[0183]

[0184]

[0185] The phosphor composition, which is part of the top layer 420b, includes a first phosphor, a second phosphor, a third phosphor, and a fourth phosphor. Under blue light excitation, the wavelength peak of the first phosphor is 490 - 500 nm, and the full width at half maximum (FWHM) is 29 - 32 nm; under blue light excitation, the wavelength peak of the second phosphor is 520 - 540 nm, and the FWHM is 110 - 115 nm; under blue light excitation, the wavelength peak of the third phosphor is 660 - 672 nm, and the FWHM is 15 - 18 nm; under blue light excitation, the wavelength peak of the fourth phosphor is 600 - 612 nm, and the FWHM is 72 - 75 nm or the wavelength peak is 620 - 628 nm, and the FWHM is 16 - 18 nm or the wavelength peak is 640 - 650 nm, and the FWHM is 85 - 90 nm. The median particle size (D50) of any one of the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor ranges from 15 to 20 μm. The D50 range of the second phosphor and the third phosphor is preferably 15 - 16 μm, and the D50 range of the first phosphor and the fourth phosphor is preferably 16 - 20 μm. When the phosphor is excited by blue light, different top layer thicknesses with the same phosphor concentration will affect the full width at half maximum of the phosphor. In this embodiment, the thickness of the top layer 420b is 80 - 100 μm. The weight percentages of each phosphor in the phosphor composition are: the first phosphor is 5.45 - 5.55%, the second phosphor is 70 - 88%, the third phosphor is 0.6 - 7%, and the fourth phosphor is the balance. When the phosphor is formulated at a certain ratio of phosphor to glue, phosphors with different peak wavelengths are selected. Under the conditions of a blue LED chip with a wavelength peak of 451 nm and an FWHM of 16.3 nm and a current of 30 mA, the measured light performance is shown in Table 1:

[0186] Table 1

[0187]

[0188] It can be seen from Nos. 1 to 4 in Table 1 that the contents of the third phosphor and the fourth phosphor in the prepared phosphor composition will affect the luminous efficacy (Eff), the average color rendering index (Ra), and the saturated red (R9). From Nos. 1 and 2, it can be known that when the content of the fourth phosphor with a peak wavelength of 670 nm increases, Eff will increase, while Ra and R9 will decrease; when the phosphor with a peak wavelength of 630 nm is used instead of the phosphor with a peak wavelength of 652 nm, it can be seen from Nos. 3 and 4 in Table 1 that when the content of the fourth phosphor with a peak wavelength of 670 nm increases, Eff will decrease, while Ra and R9 will increase. Therefore, according to actual needs, when selecting the fourth phosphor with different peak wavelengths, the dosages of the third phosphor and the fourth phosphor can be adjusted to obtain better luminous performance.

[0189] Ratio of phosphor to glue

[0190] Using the same phosphor, the ratio of the phosphor composition to the glue is prepared as shown in Table 2. It can be seen from Table 2 that when the ratio of the phosphor composition to the glue is different, Eff, Ra, R9, and CCT are all different. The more the proportion of the phosphor composition in the glue, the lower Eff, Ra, and CCT, while R9 shows a trend of decreasing first and then increasing; in addition, when the phosphor composition is combined with glue (such as silica gel) as the top layer of the LED filament, during the production of the top layer, due to the specific gravity of the phosphor composition being greater than that of silica gel, significant sedimentation of the phosphor will occur, resulting in color temperature drift of the white light LED. The greater the proportion of the phosphor, the more the phosphor sedimentation, and the more serious the color temperature drift. Therefore, the weight ratio of the phosphor composition to the glue in the top layer is 0.2 - 0.3:1, preferably 0.25 - 0.3:1. In one embodiment, a certain amount of hollow glass microspheres can be added to the phosphor composition. When the phosphor sediments, the glass microspheres float up. During the floating process, the degree of backscattering / emission of light decreases, offsetting the effect of light scattering caused by the phosphor sedimentation. Therefore, the color temperature drift phenomenon can be alleviated. In addition, since the absorption of visible light by the microspheres is small, adding glass microspheres has little impact on the initial brightness of the white light LED. The mass ratio of the glass microspheres to the phosphor composition is 1:5 - 15, preferably the weight ratio of the glass microspheres to the phosphor composition is 1:10 - 15.

[0191] Table 2

[0192]

[0193] In one embodiment, an LED filament is provided. The LED filament is made of the above-mentioned phosphor composition combined with a blue light chip. The peak wavelength of the blue light chip is 450 - 500 nm, and the full width at half maximum is 15 - 18 nm.

[0194] In some embodiments, the phosphor composition that is part of the top layer 420b includes a first phosphor, a second phosphor, and a third phosphor. When excited by blue light, the first phosphor has a peak wavelength in the range of 500 - 550 nm and a full width at half maximum (FWHM) in the range of 100 - 130 nm; the second phosphor has a peak wavelength in the range of 580 - 620 nm and a FWHM in the range of 70 - 90 nm when excited by blue light; the third phosphor has a peak wavelength in the range of 620 - 670 nm and a FWHM in the range of 70 - 95 nm when excited by blue light. The median particle size (D50) of any one of the first phosphor, the second phosphor, and the third phosphor ranges from 15 to 20 μm. The D50 of the first phosphor preferably ranges from 15 to 16 μm, and the D50 of the second phosphor and the third phosphor preferably ranges from 16 to 20 μm. When the phosphor is excited by blue light, different top layer thicknesses with the same phosphor concentration will affect the FWHM of the phosphor. In this embodiment, the thickness of the top layer 420b is 80 - 100 μm. The amount of the first phosphor in the phosphor composition is less than or equal to ten times the sum of the amounts of the second phosphor and the third phosphor, that is, the amount of the first phosphor ≤ 10 × (the amount of the second phosphor + the amount of the third phosphor). The weight ratio of the phosphor composition to the glue in the top layer is 0.4 - 0.8:1. The closer the amounts of the phosphor composition and the silicone are, the higher the light conversion efficiency of the light emitted by the LED chip. In addition, the contact area between the phosphor and the LED chip increases, and the heat dissipation efficiency of the heat generated by the LED chip is improved.

[0195] Such as Figure 1NAs shown, in one embodiment, an LED filament is provided. Its basic structure can be the same as that in the previous embodiment, that is, the LED filament includes a light conversion layer 420, an LED chip 442, and an electrode 410. The LED chips 442 are connected by a first wire 440, and the LED chip 442 and the electrode 410 are connected by a second wire 450. The light conversion layer 420 wraps the LED chip 442 and at least a part of the electrode 410. At the same time, the basic structure or material composition of the light conversion layer 420 in this embodiment can also be the same as that in the previous embodiment. The LED chips 442 in this embodiment form an LED segment 402. In this embodiment, at the junction of the light conversion layer 420 and the electrode 410, the light conversion layer 420 forms a joint portion 460. The joint portion 460 wraps at least a part of the electrode 410, and the joint portion 460 does not cover (or include) the LED chip 442. In this embodiment, one end of the electrode 410 is exposed outside the joint portion 460, while the other end is wrapped / covered by the joint portion 460. The joint portion 460 extends beyond the end of one end of the electrode 410 in the length direction of the LED filament, and does not cover any LED chip 442 in the radial projection direction of the LED filament. The proportion of phosphor and / or heat dissipation particles in the light conversion layer 420 at the joint portion 460 is lower than that in the light conversion layer 420 at the LED segment 402. By reducing the proportion of phosphor and / or heat dissipation particles in the light conversion layer 420 at the joint portion 460 (and thus increasing the proportion of silica gel), its flexibility can be increased, preventing cracking of the joint portion 460 when bent due to the stress generated by the bending of the electrode 410. Otherwise, cracking of the joint portion 460 may cause the second wire 450 at the joint portion 460 to break.

[0196] As Figure 1N shown, the joint portion 460 includes a sleeve 470, and the phosphor content of the sleeve 470 is lower than that of the light conversion layer 420 at the LED segment 402. By providing the sleeve 470, the overall phosphor proportion of the light conversion layer 420 at the joint portion 460 can be reduced, that is, the phosphor content in the area where the light conversion layer 420 is covered by the sleeve 470 (this area may include the sleeve 470 itself) is lower than that of the light conversion layer 420 at the LED segment 402. In some embodiments, the sleeve 470 does not contain phosphor or heat dissipation particles.

[0197] A part of the sleeve 470 is directly sleeved outside the electrode 410, and another part is sleeved outside the light conversion layer 420 at the joint 460. The light conversion layer 420 included in the sleeve 470 and the sleeve 470 itself together form the joint 460. Structurally, by providing the sleeve 470, the light conversion layer 420 at the joint 460 can also be prevented from cracking. One end of the sleeve 470 extends beyond one end of the electrode 410 in the filament length direction. The sleeve 470 can be sleeved on either one or both ends of the LED filament. The proportion of the area where the sleeve 470 is sleeved (covers) the light conversion layer 420 in the LED filament length direction is less than 10%, that is, the total length of the sleeve 470 covering the light conversion layer 420 is less than 10% of the total length of the LED filament (excluding the electrode 410), thereby ensuring that the light-emitting area and total light output of the LED filament are not affected by the sleeve 470, and at the same time, the sleeve 470 can play the function of strengthening the structure of the LED filament.

[0198] In some embodiments, the sleeve 470 can be made of a transparent or translucent material (i.e., a light-transmitting material) to reduce the light loss when light passes through the sleeve 470. In some embodiments, the color of the sleeve 470 is the same as or substantially the same as the color of the light conversion layer 420 to maintain the color consistency of the appearance of the filament. The sleeve 470 can be a heat-shrinkable tube, that is, when the sleeve 470 is sleeved on the electrode 410 and the light conversion layer 420, by heating the sleeve 470, the sleeve 470 shrinks and is sleeved on the electrode 410 and the light conversion layer 420. Specifically, the sleeve 470 can be made of thermoplastic materials such as PVC, PE, PP, PET, OPP, PVDC, POF, etc. The above materials are all prior arts and will not be elaborated here.

[0199] In some embodiments, glue is coated outside the light conversion layer 420 at the joint 460 to form the aforementioned sleeve 470. When the sleeve 470 is formed by glue, it can either not directly cover at least a part of the surface of the electrode 410 or directly cover at least a part of the surface of the electrode 410.

[0200] As Figure 1O shown, in some embodiments, the phosphor ratio of the light conversion layer 420 at the joint 460 is lower than that of the light conversion layer 420 of the LED segment 402, and the silicone ratio of the light conversion layer 420 at the joint 460 is higher than that of the light conversion layer 420 of the LED segment 402, so that the light conversion layer 420 at the joint 460 has better bendability, thereby reducing the risk of its cracking.

[0201] See Figure 1P, in one embodiment, the electrode 410 has a second portion 4102 wrapped or covered by the light conversion layer 420 and a first portion 4101 exposed outside the light conversion layer 420. Among them, in the length direction of the LED filament, the bending performance of the second portion 4102 is better than that of the first portion 4101. In other words, when the same force is applied to the first portion 4101 and the second portion 4102, the warping amplitude of the first portion 4101 is smaller than that of the second portion 4102. Therefore, the second portion 4102 can have a bending performance closer to that of the light conversion layer 420, and the probability of the light conversion layer 420 being broken due to stress caused by the too large difference in the bending performance between the second portion 4102 and the light conversion layer 420 when the LED filament is bent can be reduced.

[0202] In this embodiment, the first portion 4101 and the second portion 4102 have different bending performances due to different structural designs. Specifically, the area per unit length of the second portion 4102 is smaller than the area per unit length of the first portion 4101, so that the second portion 4102 has better bending performance.

[0203] The second portion 4102 has a terminal 41021, a bending section 41022, and a connecting section 41023. The terminal 41021, the bending section 41022, and the connecting section 41023 are arranged in sequence in the length direction of the second portion 4102, and the connecting section 41023 is connected to the first portion 4101. Among them, the area per unit length of the bending section 41022 is smaller than the area per unit length of the terminal 41021 and the connecting section 41023 respectively, so that when the second portion 4102 is stressed, its main bending part is the bending section 41022.

[0204] The area per unit length of the connecting section 41023 is larger than the area per unit length of the connecting section 41023 and the terminal 41021 respectively, so that the end of the light conversion layer 420 and the electrode 410 have a larger bonding area, so as to improve the bonding fastness and prevent cracking at the joint between the end of the light conversion layer 420 and the electrode 410 when the LED filament is bent.

[0205] As Figure 1P shown, one or more groups of groove portions 41024 are provided on one side or both sides in the width direction of the bending section 41022 to reduce the area per unit length of the bending section 41022 and improve the overall bendability. In addition, through the setting of the groove portions 41024, the bonding fastness between the electrode 410 and the light conversion layer 420 can also be improved. Specifically, the material of the light conversion layer 420 can pass through the groove portions 41024, so that the light conversion layer 420 on both sides of the electrode 410 is connected through the material of the light conversion layer 420 in the groove portions 41024, forming a connection method similar to riveting.

[0206] As Figure 1RAs shown, one or more sets of holes 41025 are provided at the bent section 41022 to reduce the area per unit length of the bent section 41022. Additionally, by providing the holes 41025, the bonding strength between the electrode 410 and the light conversion layer 420 can also be improved. Specifically, the material of the light conversion layer 420 can pass through the holes 41025, so that the light conversion layers 420 on the front and back sides of the electrode 410 are connected by the material of the light conversion layer 420 in the holes 41025.

[0207] As Figure 1P and Figure 1Q shown, a through hole 41026 can be provided at the end 41021 of the electrode 410 to improve the bonding strength between the end 41021 and the light conversion layer 420. The material of the light conversion layer 420 can pass through the through hole 41026, so that the light conversion layers 420 on the front and back sides of the electrode 410 are connected by the material of the light conversion layer 420 in the through hole 41025, forming a connection method similar to riveting.

[0208] As Figure 1P and Figure 1R shown, an arc surface 41027 is provided at the end of the end 41021 of the electrode 410 to prevent stress concentration caused by the sharp corners formed at the end 41021, forcing the light conversion layer 420 to crack or even break. In some embodiments, the end of the end 41021 is configured as a spherical surface to achieve the same technical effect.

[0209] In some embodiments, the second part 4102 and the first part 4101 are made of different materials, so that the second part 4102 has better bending performance than the first part 4101.

[0210] As Figure 1S shown, in some embodiments, the thickness (average thickness) of the second part 4102 is less than the thickness (average thickness) of the first part 4101, so that the second part 4102 has better bending performance than the first part 4101.

[0211] As Figure 1T shown, in one embodiment, an LED filament is provided. Its basic structure can be the same as that in the previous embodiments, that is, the LED filament includes a light conversion layer 420, an LED chip 442, and an electrode 410. The LED chips 442 are connected by a first wire 440, and the LED chips 442 and the electrode 410 are connected by a second wire 450. The light conversion layer 420 wraps the LED chips 442 and at least a part of the electrode 410. At the same time, the basic structure or material composition of the light conversion layer 420 in this embodiment can also be the same as that in the previous embodiments.

[0212] In this embodiment, the first wire 440 has a first portion 44001, and the first portion 44001 is located between two groups of LED chips 442 in the length direction of the LED filament (in the projection direction of the width / thickness of the LED filament, the first portion 44001 is located between the tangents of the edges of the two groups of LED chips 442). When the LED filament is bent, the area between the LED chips 442 is the main bending area (the part with the LED chips 442 is not easily bent). To reduce the risk that the first portion 44001 of the first wire 440 is broken when the LED filament is bent, the length L1 of the first portion 44001 is configured to be greater than the distance D1 between the two groups of LED chips 442. In other words, the length L1 of the first portion 44001 is configured to be greater than the projection length of the first portion 44001 in the width direction of the LED filament, and this design provides more margin for the first wire 440 when the LED filament is bent, avoiding breakage.

[0213] In some embodiments, the ratio of the length L1 of the first portion 44001 to the distance D1 between the two groups of LED chips 442 (or the projection length of the first portion 44001 in the width direction of the LED filament) is greater than 1.1, 1.2, 1.3 or 1.4. So that when the LED filament is bent, the first portion 44001 has enough length to deform with the bending to prevent the first portion 44001 from being broken. In some embodiments, it is greater than the projection length of the first portion 44001 in the width direction of the LED filament.

[0214] In some embodiments, the ratio of the length L1 of the first portion 44001 to the distance D1 between the two groups of LED chips 442 (or the projection length of the first portion 44001 in the width direction of the LED filament) is less than 2. If the length of the first portion 44001 is configured too long, it will be unfavorable for the covering effect of the light conversion layer 420, and even the first wire 44001 may be exposed outside the light conversion layer 420. In addition, the too long first portion 44001 also causes material waste.

[0215] In some embodiments, the first portion 44001 is configured to be arc-shaped so that its length L1 is greater than the distance D1 between the two groups of LED chips 442 (the projection length of the first portion 44001 in the width direction of the LED filament).

[0216] As Figure 1U shown, in some embodiments, the first portion 44001 is configured to be wavy or spiral so that its length is greater than the distance between the two groups of LED chips 442 (the projection length of the first portion 44001 in the width direction of the LED filament).

[0217] As Figure 1VAs shown, in some embodiments, the first portion 44001 (or the entire first wire 440) of the LED filament is generally in an "m" shape when viewed from the side of the LED filament. This makes the first portion 44001 of the first wire 440 longer per unit length and have greater cushioning during the bending of the LED filament, so as to prevent the first portion 44001 from being pulled and broken.

[0218] Figures 1T to 1V When the shown LED filament is bent, usually the side of the LED chip 442 with the first wire 440 is arranged on the outside (i.e., facing the outside of the lamp body), while the other side is arranged on the inside (i.e., facing the inside of the lamp body). As Figures 1T to 1V For the distance, usually both sides in the length direction of the LED filament are bent downward so that the side of the LED chip 442 with the first wire is located on the outside of the LED filament (i.e., facing the outside of the lamp body). By Figures 1T to 1V The configuration of the first wire 440 in the embodiment can make the LED filament have good bendability and ensure that the first wire 440 will not be pulled and broken due to excessive bending amplitude of the LED filament. For example, the LED filament can be bent into a shape with the radius of curvature at the maximum curvature less than 10 mm, 8 mm or 5 mm. Considering that the maximum curvature part after the LED filament is bent is not necessarily an arc, the following expression can be used, that is, on the premise that the LED chip 422 is electrically connected by a wire, after the LED filament is bent, the maximum inscribed circle radius at the maximum curvature part is less than 15 mm, 10 mm or 8 mm. That is to say, in the case where the LED filament in this embodiment uses the first wire 440 to electrically connect the LED chip 442, it can be achieved that after the LED filament is bent, the maximum inscribed circle radius at the maximum curvature part is less than 15 mm, 10 mm or 8 mm, and it is ensured that the first wire 440 is not pulled and broken. In the prior art, for an LED filament using a flexible substrate to carry the LED chip and realize the electrical connection between the LED chips, since it does not have a wire and there is no risk of wire breakage, it may have a greater bending amplitude, but obviously the two cannot be compared.

[0219] In this embodiment, after the LED filament is bent, the maximum inscribed circle at the maximum curvature part should be greater than 3 or 3.5 mm to reduce the risk of pulling and breaking the first wire 440 due to excessive bending amplitude.

[0220] To ensure the bendability of the LED filament or further improve it, the position of the first wire 440 can also be set. When the LED filament is bent as described above (i.e., the side of the LED chip 442 with the first wire 440 is arranged outside, while the other side is arranged inside), the curvature radius of the part of the LED filament closer to the outside at the bending part is larger, and the deformation or tension generated inside this part is also larger. Therefore, the first wire 440 can be set as far as possible from the surface 401 in the width (or thickness) direction of the LED filament, and this surface 401 is the surface of the side of the LED chip 442 with the first wire 440. To Figure 1V As an example, the shortest distance from the first wire 442 to the surface 401 is L, and the width (or thickness) dimension of the LED filament is D, and the ratio of L to D is at least greater than 0.1.

[0221] In this embodiment, the first wire 440 has a second part 44002. When the second part 44002 is projected onto the corresponding LED chip 442 in the width direction of the LED filament, it completely falls within the range defined by the LED chip 442. One end of the second part 44002 is connected to the LED chip 442, and the other end is connected to the first part 44001 (the first part 44001 and the second part 44002 can be of an integral structure). In other words, one end of the second part 44002 is connected to the LED chip 442, and the other end does not extend beyond the corresponding LED chip 442 in the length direction of the LED filament.

[0222] In this embodiment, the length L2 of the second part 44002 is greater than the distance D2 from the connection point of the second part 44002 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projected length of the second part 44002 in the width direction of the LED filament). When the LED filament is bent, the first part 44001 will pull the second part 44002 after being bent, and the above setting of the second part 44002 can enable the second part 44002 to have a deformation space to prevent the connection point between it and the LED chip 442 from breaking due to the tension of the first part 44001.

[0223] In this embodiment, the first wire 440 has two groups of second parts 44002, and at least one group of the second parts 44002 is set as described above.

[0224] In some embodiments, the ratio of the length L2 of the second portion 44002 to the distance D2 from the connection point of the second portion 44002 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projected length of the second portion 44002 in the width direction of the LED filament) is greater than 1.15, 1.2, 1.3 or 1.4. This is to reduce the risk that the connection point between the second portion 44002 and the LED chip 442 breaks due to tension.

[0225] In some embodiments, the ratio of the length L2 of the second portion 44002 to the distance D2 from the connection point of the second portion 44002 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projected length of the second portion 44002 in the width direction of the LED filament) is less than 2. If the second portion 44002 is too long, then the second portion 44002 will necessarily have a greater bending amplitude or occupy more space in the width direction of the LED filament, both of which will have an adverse impact on the LED filament (for example, a greater bending amplitude may result in greater internal stress in the second portion 44002, and if it occupies more space in the width direction of the LED filament, a thicker light conversion layer needs to be covered, resulting in the LED filament becoming thicker).

[0226] In this embodiment, the ratio of the length L2 of the second portion 44002 to the distance D2 from the connection point of the second portion 44002 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projected length of the second portion 44002 in the width direction of the LED filament) is greater than the ratio of the length L1 of the first portion 44001 to the distance D1 between two groups of LED chips 442 (or the projected length of the first portion 44001 in the width direction of the LED filament). Expressed by the formula as follows:

[0227] L2 / D2 > L1 / D1

[0228] Generally, when the LED filament is bent, the connection point between the second portion 44002 and the LED chip 442 is more likely to break due to tension. Therefore, by setting L2 / D2 > L1 / D1, the risk that the connection point between the second portion 44002 and the LED chip 442 breaks can be reduced.

[0229] In some embodiments, both the first portion 44001 and the second portion 44002 are arc-shaped, and the radius of curvature of the second portion 44002 is less than the radius of curvature of the first portion 44001, so that the first portion 44001 and the second portion 44002 satisfy the above formula, that is, L2 / D2 > L1 / D1.

[0230] In other embodiments, it can also be set that L1 / D1 > L2 / D2. In this way, when the LED filament is bent, the first wire (i.e., the first part) in the main bending area has sufficient buffer space and is not easily broken.

[0231] In this embodiment, the second wire 450 can also be configured as described above. Specifically, the second wire 450 includes a first part 4501, and the first part 4501 is located between the LED chip 442 and the electrode 410 in the length direction of the LED filament. When the LED filament is bent, the area between the LED chip 442 and the electrode 410 can be one of the bending areas (the areas with the LED chip 442 and the electrode 410 are not easily bent). To reduce the risk of the first part 45001 of the second wire 450 being broken when the LED filament is bent, the length L3 of the first part 4501 is configured to be greater than the distance D3 between the LED chip 442 and the electrode 410. In other words, the length L3 of the first part 4501 is configured to be greater than the projection length of the first part 4501 in the width direction of the LED filament.

[0232] In some embodiments, the ratio of the length L3 of the first part 4501 to the distance D3 between the LED chip 442 and the electrode 410 (or the projection length of the first part 4501 in the width direction of the LED filament) is greater than 1.1, 1.2, 1.3, or 1.4. So that when the LED filament is bent, the first part 4501 has sufficient length to deform with the bending to prevent the first part 4501 from being broken.

[0233] In some embodiments, the ratio of the length L3 of the first part 4501 to the distance D3 between the LED chip 442 and the electrode 410 (or the projection length of the first part 4501 in the width direction of the LED filament) is less than 2. If the length of the first part 4501 is configured too long, it will be unfavorable for the covering effect of the light conversion layer 420, and even the first wire 4501 may be exposed outside the light conversion layer 420. In addition, the too long first part 4501 also causes material waste.

[0234] In some embodiments, the first part 4501 is configured as an arc so that its length L3 is greater than the distance D3 between the LED chip 442 and the electrode 410 (the projection length of the first part 44001 in the width direction of the LED filament).

[0235] As Figure 1U shown, in some embodiments, the first part 4501 is configured as a wavy shape so that its length is greater than the distance between the LED chip 442 and the electrode 410 (the projection length of the first part 44001 in the width direction of the LED filament).

[0236] In this embodiment, the second wire 450 has a second portion 4502. When the second portion 4502 is projected onto the corresponding LED chip 442 in the width direction of the LED filament, it completely falls within the range defined by the LED chip 442. One end of the second portion 4502 is connected to the LED chip 442, and the other end is connected to the first portion 4501 (the first portion 4501 and the second portion 4502 may be of an integral structure). In other words, one end of the second portion 4502 is connected to the LED chip 442, and the other end does not extend beyond the corresponding LED chip 442 in the length direction of the LED filament.

[0237] In this embodiment, the length L4 of the second portion 4502 is greater than the distance D4 from the connection point of the second portion 4502 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projection length of the second portion 4502 in the width direction of the LED filament). When the LED filament is bent, the first portion 4501 after being bent will pull the second portion 4502, and the above setting of the second portion 4502 can enable the second portion 4502 to have a deformation space to prevent the connection point between it and the LED chip 442 from breaking due to the pulling force of the first portion 4501.

[0238] In some embodiments, the ratio of the length L4 of the second portion 4502 to the distance D4 from the connection point of the second portion 4502 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projection length of the second portion 4502 in the width direction of the LED filament) is greater than 1.15, 1.2, 1.3, or 1.4. To reduce the risk of the connection point between the second portion 4502 and the LED chip 442 breaking due to the pulling force.

[0239] In some embodiments, the ratio of the length L4 of the second portion 4502 to the distance D4 from the connection point of the second portion 4502 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projection length of the second portion 4502 in the width direction of the LED filament) is less than 2. If the second portion 4502 is too long, then the second portion 4502 will inevitably have a larger bending amplitude or occupy the space in the width direction of the LED filament, both of which will have an adverse impact on the LED filament (such as a larger bending amplitude may lead to greater internal stress in the second portion 4502, and if it occupies the space in the width direction of the LED filament, a thicker light conversion layer needs to be covered, resulting in the LED filament becoming thicker).

[0240] In this embodiment, the ratio of the length L4 of the second part 4502 to the distance D4 from the connection point of the second part 4502 and the LED chip 442 to the end of the LED chip 442 in the length direction (the projection length of the second part 4502 in the width direction of the LED filament) is greater than the ratio of the length L3 of the first part 4501 to the distance D3 between the LED chip 442 and the electrode 410 (or the projection length of the first part 4501 in the width direction of the LED filament). It is expressed by the formula as follows:

[0241] L4 / D4 > L3 / D3

[0242] Generally, when the LED filament is bent, the connection point of the second part 4502 and the LED chip 442 is more likely to be broken by the tensile force. Therefore, by setting L4 / D4 > L3 / D3, the risk of the connection point of the second part 4502 and the LED chip 442 being broken can be reduced.

[0243] In some embodiments, both the first part 4501 and the second part 4502 are arc-shaped, and the radius of curvature of the second part 4502 is smaller than that of the first part 4501, so that the first part 4501 and the second part 4502 satisfy the above formula, that is, L4 / D4 > L3 / D3.

[0244] In some embodiments, the second wire 450 has a third part 4503. When the third part 4503 is projected in the width direction of the LED filament onto the mating electrode 410, it completely falls within the range defined by the electrode 410. One end of the third part 4503 is connected to the electrode 410, and the other end is connected to the first part 4501 (the first part 4501 and the third part 4503 may be integrally formed). In other words, one end of the third part 4503 is connected to the electrode 410, and the other end does not extend beyond the mating electrode 410 in the length direction of the LED filament.

[0245] In this embodiment, the length L5 of the third part 4503 is greater than the distance D5 from the connection point of the third part 4502 and the electrode 410 to the end of the electrode 410 in the length direction (the projection length of the third part 4503 in the width direction of the LED filament). When the LED filament is bent, the first part 4501 will pull the third part 4503 after being bent. With the above setting of the third part 4503, the third part 4503 can have a deformation space to prevent the connection point between it and the electrode 410 from being broken due to the tensile force of the first part 4501.

[0246] In some embodiments, the ratio of the length L5 of the third part 4502 to the distance D5 from the connection point of the third part 4503 and the electrode 410 to the end of the electrode 410 in the length direction thereof (the projected length of the third part 4503 in the width direction of the LED filament) is greater than 1.15, 1.2, 1.3 or 1.4. This is to reduce the risk that the connection point between the third part 4503 and the electrode breaks due to tensile force.

[0247] In some embodiments, the ratio of the length L5 of the third part 4503 to the distance D5 from the connection point of the third part 4503 and the electrode 410 to the end of the electrode 410 in the length direction thereof (the projected length of the third part 4503 in the width direction of the LED filament) is less than 2. If the third part 4503 is too long, then the third part 4503 is bound to have a greater bending amplitude or occupy more space in the width direction of the LED filament, both of which will have an adverse impact on the LED filament (for example, a greater bending amplitude may lead to greater internal stress in the third part 4503, and if it occupies more space in the width direction of the LED filament, a thicker light conversion layer needs to be covered, resulting in the LED filament becoming thicker).

[0248] Please refer to Figure 4A and Figures 4B to 4D , Figure 4A shown is a schematic diagram of an LED bulb 40h according to an embodiment of the present application, Figures 4B to 4D shown are respectively Figure 4A the side view, the other side view and the top view of the LED bulb 40h. In this embodiment, as Figures 4A to 4D shown, the LED bulb includes a lamp housing 12, a lamp head 16 connected to the lamp housing 12, at least two conductive brackets provided in the lamp housing 12, a cantilever (not shown in the figure), a core column 19 and a single LED filament 100. The core column 19 includes a core column bottom and a core column top which are opposite to each other. The core column bottom is connected to the lamp head 16, and the core column top extends into the interior of the lamp housing 12. For example, the core column top may be located at a position approximately in the center of the interior of the lamp housing 12. The conductive brackets are connected to the core column 19. The LED filament 100 includes a filament body and two filament electrodes (or electrodes or conductive electrodes) 110, 112. The two filament electrodes 110, 112 are located at opposite ends of the filament body. The filament body is the other part of the LED filament 100 excluding the filament electrodes 110, 112. The two filament electrodes 110, 112 are respectively connected to the two conductive brackets. One end of the cantilever is connected to the core column 19 and the other end is connected to the filament body.

[0249] During the manufacturing process of traditional bulb lamps, in order to prevent the tungsten wire from burning, oxidizing, and breaking due to contact with air, a glass structure with a flared core column is designed to be sleeved at the opening of the glass lamp shell and sintered for sealing. Then, a vacuum pump is connected through the port of the flared core column to evacuate the air inside the lamp shell and replace it with nitrogen, preventing the tungsten wire inside the lamp shell from burning and oxidizing. Finally, the port of the flared core column is sintered and sealed. Therefore, the vacuum pump can evacuate the air inside the lamp shell and replace it with pure nitrogen or a suitable proportion combination of nitrogen and helium to improve the thermal conductivity of the gas inside the lamp shell and also remove the water mist hidden in the air. In one embodiment, it can also be replaced with a suitable proportion combination of nitrogen and oxygen or nitrogen and air, where the oxygen or air content is 1-10% of the volume of the lamp shell, preferably 1-5%. When the base layer contains saturated hydrocarbons, during the use of the LED bulb lamp, the saturated hydrocarbons will generate free radicals under the action of light, heat, stress, etc. The generated free radicals or activated molecules combine with oxygen to form peroxide free radicals. Filling the lamp shell with oxygen can improve the heat resistance and light resistance of the base layer containing saturated hydrocarbons.

[0250] During the preparation process of the LED bulb lamp, in order to improve the refractive index of the light emitted by the LED filament by the lamp shell 12, some foreign substances, such as rosin, can be attached to the inner wall of the lamp shell 12. The average thickness of the foreign substance deposition per square centimeter of the inner wall area of the lamp shell 12 is 0.01-2 mm, and preferably the thickness of the foreign substance is 0.01-0.5 mm. In one embodiment, the foreign substance content per square centimeter of the inner wall area of the lamp shell 12 accounts for 1%-30% of the foreign substance content on the entire inner wall of the lamp shell 12, preferably 1%-10%. The above foreign substance content can be adjusted, for example, by vacuum drying the lamp shell. In another embodiment, a part of the impurities can be left in the gas filled in the lamp shell 12, and the impurity content in the filled gas is 0.1%-20% of the volume of the lamp shell 12, preferably 0.1-5%. The impurity content can be adjusted, for example, by vacuum drying the lamp shell. Since there are a small amount of impurities in the filled gas, the light emitted by the LED filament is scattered or refracted by the impurities, increasing the light-emitting angle, which is beneficial to improving the light-emitting effect of the LED filament.

[0251] The LED bulb is located in a spatial coordinate system (X, Y, Z), where the Z-axis is parallel to the stem 19. The projected lengths of the LED filament in the XY plane, YZ plane, and XZ plane are length L1, length L2, and length L3, respectively. In one embodiment, the ratio of length L1, length L2, and length L3 is 0.8:1:0.9. In one embodiment, the ratio of length L1, length L2, and length L3 is (0.5 to 0.9):1:(0.6 to 1), and the ratio of length L1, length L2, and length L3 is close to 1:1:1, and the LED bulb has a better lighting effect and realizes full-circle light. When the LED filament 100 is bent, it has at least one first bending point and at least two second bending points. The first bending points and the second bending points are arranged at intervals, and the height of any first bending point on the Z-axis is greater than that of any second bending point. In one embodiment, the distance between two adjacent first bending points on the Y-axis or X-axis is equal, and the appearance of the LED filament is neat and beautiful. In one embodiment, the distance between two adjacent first bending points on the Y-axis or X-axis has a maximum value D1 and a minimum value D2, and the range of D2 is 0.5D1 to 0.9D1, and the luminous flux distribution on each plane is relatively uniform. Let the diameter of the lamp cap 16 be R1 (see Figure 4B ), the maximum diameter of the lamp housing 12 or the maximum horizontal distance of the lamp housing 12 in the YZ plane be R2 (see Figure 4B ), and the maximum width of the LED filament 100 in the Y-axis direction in the YZ plane (see Figure 4B ) or the maximum width in the X-axis direction in the XZ plane be R3 (see Figure 4C ). R3 is between R1 and R2, that is, R1 < R3 < R2. When the LED filament is bent, the distance between adjacent first bending points and / or adjacent second bending points in the Z-axis direction is relatively wide, which is beneficial to improving the heat dissipation effect of the LED filament. In the manufacturing process of the LED bulb, the LED filament 100 can be first placed in the inner space of the lamp housing 12 in a folded manner, and then the LED filament 100 can be stretched in the lamp housing 12 manually or mechanically, so that the maximum length of the LED filament 100 in the XZ plane satisfies the above relationship.

[0252] As Figures 4A to 4D shown, in this embodiment, the conductor segment 130 of the LED filament 100 is one, and there are two LED segments 102 and 104. Each two adjacent LED segments 102 and 104 are connected through the conductor segment 130. The bending pattern of the LED filament 100 at the highest point presents an arc bend, that is, the LED segments 102 and 104 respectively present an arc bend at the highest point of the LED filament 100, and the conductor segment also presents an arc bend at the lowest point of the LED filament. The LED filament 100 can be defined as that after each bent conductor segment 130, a segment is connected, and each LED segment 102 and 104 forms a corresponding segment.

[0253] Moreover, since the LED filament 100 adopts a flexible base layer, the flexible base layer preferably adopts a silicone-modified polyimide resin composition, and the silicone-modified polyimide resin composition includes silicone-modified polyimide, a thermal curing agent, heat dissipation particles, and phosphor. In this embodiment, the two LED segments 102 are respectively bent to form an inverted U shape, and the conductor segment 130 is located between the two LED segments 102, and the bending degree of the conductor segment 130 is the same as or greater than that of the LED segment 102. That is to say, the two LED segments 102 are respectively bent to form an inverted U shape at the high point of the LED filament and have a bending radius value r1, and the conductor segment 130 is bent at the low point of the LED filament 100 and has a bending radius value r2, where r1 is greater than r2. Through the arrangement of the conductor segment 130, the LED filament 100 can be bent with a small turning radius within a limited space. In one embodiment, the bending points of the LED segment 102 and the LED segment 104 are at the same height in the Z direction. Due to the certain symmetry of the LED filament, the light emission of the LED bulb is relatively uniform. In one embodiment, the heights of the bending points of the LED segment 102 and the LED segment 104 in the Z direction are different. For example, the height of the bending point of the LED segment 102 is greater than the height of the bending point of the LED segment 104. When the LED filament is placed in the lamp housing in this way with the same length of the LED filament, part of the LED filament will be more inclined towards the lamp housing, so the heat dissipation effect of the LED filament is better. In addition, in the Z direction, the vertical rod 19a of this embodiment has a lower height relative to the vertical rod 19a of the previous embodiment. The height of this vertical rod 19a corresponds to the height of the conductor segment 130, or the vertical rod 19a is approximately in contact with part of the conductor segment 130. For example, the lowest part of the conductor segment 130 can be connected to the top of the vertical rod 19a to make the overall shape of the LED filament 100 not easily deformed. In different embodiments, the conductor segments 130 can be connected to each other through the perforations at the top of the vertical rod 19a, or the conductor segments 130 can be adhesively bonded to the top of the vertical rod 19a to be connected to each other, but not limited thereto. In one embodiment, the conductor segment 130 and the vertical rod 19a can be connected by a conducting wire. For example, a conducting wire is led out from the top of the vertical rod 19a to connect the conductor segment 130.

[0254] As Figure 4B shown, in this embodiment, in the Z direction, the height of the conductor segment 130 is higher than that of the two electrodes 110 and 112, and the two LED segments 102 and 104 respectively extend upward from the two electrodes 110 and 112 to the highest point, and then are bent downward to extend to the conductor segment 130 connecting the two LED segments 102 and 104. As Figure 4C shown, in this embodiment, the profile of the LED filament 100 in the XZ plane is similar to a V shape, that is, the two LED segments 102 respectively extend obliquely upward and outward, and after being bent at the highest point, they respectively extend obliquely downward and inward to the conductor segment 130.Figure 4D As shown, in this embodiment, the contour of the LED filament 100 in the XY plane has an S shape. As Figure 4B shown in Figure 4D As shown, in this embodiment, the conductor segment 130 is located between the electrodes 110 and 112. As Figure 4D shown, in this embodiment, in the XY plane, the bending points of the LED segment 102, the bending points of the LED segment 104, and the electrodes 110 and 112 are approximately located on a circumference centered on the conductor segment 130 (or the core column 19 or the vertical rod 19a). For example, in the XY plane, the bending points of the LED segment 102 and the bending points of the LED segment 104 are located on the same circumference centered on the core column 19 or the vertical rod 19a; in some embodiments, in the XY plane, the bending points of the LED segment 102, the bending points of the LED segment 104, and the electrodes 110 and 112 are located on the same circumference centered on the core column 19 or the vertical rod 19a.

[0255] Please refer to Figure 5 shown in Figure 5 As shown in the schematic diagram of the LED bulb lamp 40i according to an embodiment of the present application. The basic structure of the LED bulb lamp 40i in this embodiment is the same as that of the LED bulb lamp 40h in FIG. 4, including a lamp housing 12, a lamp head 16 connected to the lamp housing 12, at least two conductive brackets provided in the lamp housing 12, a cantilever (not shown in the figure), a core column 19, and a single LED filament 100. The difference is that the LED bulb lamp 40i in this embodiment does not have a vertical rod 19a, and the core column 19 includes an inflation tube. The gas in the lamp housing 12 is filled through the inflation tube. As Figure 5 shown, in the Z-axis direction, the shortest distance from the LED filament 100 (or the bending points of the LED segments 102 / 104) to the lamp housing 12 is H1, and the shortest distance from the conductor segment 130 of the LED filament 100 to the core column 19 is H2. H1 is less than or equal to H2. The bending points of the LED segments are closer to the lamp housing, so the heat dissipation path of the LED filament is short, thereby improving the heat dissipation effect of the bulb lamp. In other embodiments, H1 is greater than H2, so the LED filament is approximately located in the middle area of the lamp housing, and the light-emitting effect is better.

[0256] Referring to FIG. 6, FIG. 6 is a schematic structural diagram of a lamp cap according to an embodiment of the present application. In this embodiment, a power supply component (or driving power supply) 20 is provided inside the lamp cap 16. The power supply component is electrically connected to the LED filament, and the power supply component is electrically connected to the electrodes of the LED filament. The power supply component 20 includes a substrate 201. A heating element (an element that generates more heat during operation, such as an IC, a resistor, etc.) and a heat-sensitive element (such as an electrolytic capacitor, etc.) are provided on the substrate 201. The lamp cap 16 has an inner surface and an outer surface opposite to the inner surface. The outer surface of the lamp cap 16 is away from the power supply component 20. The heating element is closer to the inner surface of the lamp cap 16 than the heat-sensitive element. An insulating sheet 202 is provided on the heating element, and the insulating sheet 202 is in contact with the inner surface of the lamp cap 16. For example, the insulating sheet 202 can be brought into contact with the inner surface of the lamp cap 16 by means of welding or fasteners, etc. In one embodiment, the heating element is integrally encapsulated into a component, and a heat sink is provided on the component. The heat sink is in contact with the inner surface of the lamp cap 16. For example, after encapsulating the IC and the rectifier bridge into a component, the heat sink is brought into contact with the inner surface of the lamp cap 16 by means of welding or fasteners, etc. The heat sink can be welded as a negative wire to the inner surface of the lamp cap 16.

[0257] In another embodiment, the substrate 201 is in direct contact with the inner surface of the lamp cap 16. Compared with the substrate being indirectly in contact with the lamp cap through glue, the direct contact method can improve the heat dissipation effect of the bulb lamp on the basis of reducing the heat transfer medium.

[0258] In another embodiment, a thermal conductive glue is covered on the heating element. For example, the substrate 201 has a first surface 2011 and a second surface 2012. The second surface 2012 is away from the LED filament. The heating element and the heat-sensitive element are respectively located on the first surface 2011 and the second surface 2012. The thermal conductive glue is covered on the first surface 2011. The heat generated by the heating element can be transferred to the lamp cap through the thermal conductive glue, thereby improving the heat dissipation effect of the bulb lamp.

[0259] In another embodiment, as shown in FIG. 7, a heat conducting part 203 is provided on the inner surface of the lamp cap 16. The heat conducting part 203 can be a net pocket for accommodating the heating element or a metal part in contact with the heating element, etc. The heat conductivity coefficient of the heat conducting part 203 is greater than or equal to the heat conductivity coefficient of the lamp cap 16. The heat generated by the heating element can be quickly transferred to the lamp cap 16 through the heat conducting part 203, thereby improving the heat dissipation effect of the bulb lamp.

[0260] In another embodiment, each surface of the power supply component 20 is covered with thermal conductive glue. A part of the thermal conductive glue is in contact with the inner surface of the lamp cap 16. For example, a flexible substrate can be used, and the flexible substrate is integrally installed inside the lamp cap 16, and the lamp cap 16 is filled with thermal conductive glue to achieve this. The power supply component is entirely covered with thermal conductive glue, and the heat dissipation area is increased, thereby greatly improving the heat dissipation effect.

[0261] In another embodiment, as Figure 7CAs shown, the substrate 201 is parallel to the axial direction of the lamp cap 16 (or the axial direction of the stem 19 in FIGS. 4, Figure 5 and FIG. 8). Since all the heat-generating elements can be placed on the side of the substrate close to the lamp cap, the heat generated by the heat-generating elements can be quickly transferred to the lamp cap, thereby improving the heat dissipation efficiency of the power supply assembly; in addition, the heat-sensitive elements and heat-resistant elements can be respectively arranged on different surfaces of the substrate, reducing the influence of the heat generated by the heat-generating elements during operation on the heat-sensitive elements, and improving the overall reliability and life of the power supply module. In an embodiment, the substrate 201 is provided with heat-generating elements (elements that generate more heat during operation, such as ICs, resistors, etc.) and heat-sensitive elements (such as electrolytic capacitors, etc.). The heat-generating elements are closer to the inner surface of the lamp cap 16 than other electronic elements (such as heat-sensitive elements or other non-thermally sensitive elements, such as capacitors). Therefore, compared with other electronic elements, the heat-generating elements have a shorter heat transfer distance to the lamp cap 16, which is more conducive to the heat generated by the heat-generating elements during operation being conducted to the lamp cap 16 for heat dissipation, thereby improving the heat dissipation efficiency of the power supply assembly 20.

[0262] As Figure 5 shown in FIGS. 6 to 7, the projection of the gas filling tube and the substrate 201 on the XY plane overlaps. In some embodiments, the projections of the gas filling tube and the substrate 201 on the XZ and / or YZ planes have a gap (or do not overlap), or in the height direction of the lamp cap (Z-axis direction), there is a certain distance between the gas filling tube and the substrate, and the gas filling tube and the substrate do not contact each other, increasing the accommodation space of the power supply assembly and improving the utilization rate of the substrate. In addition, when the substrate 201 contacts the inner surface of the lamp cap 16, a cavity is formed between the first surface 2011 of the substrate 201 and the stem 19. The heat generated by the heat-generating elements located on the first surface of the substrate can be transferred through the cavity, reducing the thermal influence on the heat-sensitive elements located on the second surface, thereby improving the service life of the power supply assembly.

[0263] Please refer to Figures 8A to 8D , Figures 8A to 8D shown in FIG. 14 is a schematic diagram of an LED bulb lamp 40j according to an embodiment of the present application. The LED bulb lamp 40j in this embodiment has the same basic structure as the LED bulb lamp 40h in FIG. 4, including a lamp housing 12, a lamp cap 16 connected to the lamp housing 12, at least two conductive brackets provided in the lamp housing 12, at least one cantilever 15, a stem 19, and an LED filament 100. The cantilever 15 is not shown in Figure 8B and Figure 8C . The stem 19 includes a vertical rod 19a. Each cantilever 15 includes an opposite first end and a second end. The first end of each cantilever 15 is connected to the vertical rod 19a, and the second end of each cantilever 15 is connected to the LED filament 100. Figure 8CThe difference between the shown LED bulb lamp and the bulb lamp shown in Figure 4 lies in that: in the Z-axis direction, the height of the vertical rod 19a is greater than the distance between the bottom of the vertical rod and the conductor section 130. The vertical rod 19a includes the opposite bottom and top of the vertical rod, and the bottom of the vertical rod is close to the gas-filled tube. As Figure 8D shown, in the XY plane, the central angle range corresponding to the arc where at least two bending points of the LED filament are located is 170° to 220°, so as to have an appropriate spacing between the bending points of the LED section and ensure the heat dissipation effect of the LED filament. At least one cantilever 15 is located at the bending point of the LED filament 100, for example, at the bending point of the LED section 102 / 104. Each cantilever 15 has an intersection point with the LED filament 100. In the XY plane, at least two intersection points are located on the circumference with the stem 19 (or the vertical rod 19a) as the center. In this way, the LED filament has a certain symmetry, and the luminous flux in all directions is roughly the same, and the LED bulb lamp emits light evenly. In one embodiment, a straight line La is formed by connecting at least one intersection point with the bending point of the conductor section 130, and a straight line Lb is formed by the intersection point on the straight line La and the electrodes 110 / 112 of the LED filament. The range of the angle α between the straight line La and the straight line Lb is 0° < α < 90°, preferably 0° < α < 60°, so that the LED section has an appropriate spacing after bending, and has a better light output effect and heat dissipation effect. The bending point of the LED section has a radius of curvature. For example, the bending point of the LED section 102 has a radius of curvature r3, and the bending point of the LED section 104 has a radius of curvature r4, and r3 is equal to r4, and the light output is uniform on each plane. Of course, r3 can also be set to be greater than r4 or r3 less than r4 to meet the lighting requirements and / or heat dissipation requirements in certain specific directions. The bending point of the conductor section 130 has a radius of curvature r5, and r5 is less than the maximum value of r3 and r4, that is, r5 < max(r3, r4). The LED filament is not likely to break, and there is a certain spacing between the LED sections closer to the stem, preventing the heat generated by the two LED sections from affecting each other.

[0264] In one embodiment, the LED filament includes a top layer and a carrier layer. When the LED filament is bent, in any cross-section in the height direction of the LED filament or in the cross-section of the central axis (or optical axis) of the LED chip, the carrier layer is closer to the lamp housing than the top layer, that is, the shortest distance from the carrier layer to the lamp housing is less than the shortest distance from the top layer to the lamp housing. In some embodiments, when the LED filament is bent, it has a bending point (or bending area), and at this bending point (or bending area), the radius of curvature of the carrier layer is greater than that of the top layer. In some embodiments, when the LED filament is bent, in any cross-section in the height direction of the LED filament or in the cross-section of the central axis (or optical axis) of the LED chip, the top layer is closer to the central axis (or core column) of the LED bulb than the carrier layer, and the distance from the top layer to the central axis (or core column) of the LED bulb is less than the distance from the carrier layer to the central axis (or core column) of the LED bulb. In some embodiments, when the LED filament is bent, it has a bending point (or bending area), and at a bending point (or bending area), the light-emitting surface of the LED chip faces the central axis (or core column) of the LED bulb. Through the above design, when any LED filament in the LED bulb is bent, the wires in the LED filament are subjected to less bending stress and are not easily broken. The LED segment 102 / 104 includes a first segment and a second segment. The first segment is formed by extending upward (towards the top of the lamp housing) from the electrode 110 / 112 to the bending point, and the second segment is formed by extending downward (towards the lamp head) from the bending point to the conductor segment 130 connecting the two LED segments 102 and 104. The first segment and the second segment have relative first and second distances to the lamp housing 12 respectively, and the first distance is less than the second distance. In the direction of the first distance, the base layer 420b of the LED filament is close to the lamp housing 12, and the top layer 420a of the LED filament is far from the lamp housing 12. For example Figure 8B in, the first segment of the LED segment 104 has relative first and second distances D1 and D2 to the lamp housing 12, the first distance D1 is less than the second distance D2, and in the direction of the first distance D1, the base layer 420b of the LED filament is close to the lamp housing 12, and the top layer 420a of the LED filament is far from the lamp housing 12. When the LED filament is bent, the wires in the LED filament are subjected to less bending stress and are not easily broken, improving the production quality of the LED bulb.

[0265] Please refer to Figures 4A to 4D 、 Figures 8A to 8D , a plane A divides the lamp housing 12 into an upper part and a lower part, and the lamp housing 12 has the maximum width at the plane A. For example Figure 4BThe planar figure formed by R2 (the maximum horizontal distance) lies on plane A. When the core column 19 intersects with plane A, the lamp housing 12 has a relative lamp housing top and lamp housing bottom. The lamp housing bottom is close to the lamp head 16. The length of the LED filament between the lamp housing top and plane A (or in the height direction of the LED bulb lamp, the distance from the highest point of the LED filament to plane A) is less than the length of the LED filament between plane A and the lamp housing bottom (or in the height direction of the LED bulb lamp, the distance from the lowest point of the LED filament to plane A). When the core column 19 intersects with plane A, the inner diameter of the lamp housing 12 above the top of the core column 19 is smaller, and the volume of the gas contained is small. If most of the LED filament is located above the top of the core column, it will affect the overall heat dissipation effect of the LED filament, and thus reduce the product quality. If there is a certain distance between the core column 19 and plane A and the distance from the top of the core column to plane A is less than the height of the vertical rod 19a, the core column 19 includes a relative core column bottom and core column top. The core column bottom is connected to the lamp head 16, and the core column top extends towards the lamp housing top. The length of the LED filament between the core column top and the lamp housing top (or the distance between the highest point of the LED filament and the core column top) is less than the length of the LED filament between the core column top and the lamp housing bottom (or the distance between the core column top and the lowest point of the LED filament). Most of the LED filament can be indirectly supported by the core column, thereby ensuring the stability of the LED filament shape during the transportation of the LED bulb lamp. In some embodiments, when there is a distance between the core column 19 and plane A and the distance from the top of the core column to plane A is greater than the height of the vertical rod 19a, the core column 19 includes a relative core column bottom and core column top. The core column bottom is connected to the lamp head 16, and the core column top extends towards the lamp housing top. The length of the LED filament between the core column top and the lamp housing top is greater than the length of the LED filament between the core column top and the lamp housing bottom. Since the volume of the gas contained between the top of the core column and the lamp housing bottom is large, and most of the LED filament is located between the top of the core column and the lamp housing bottom, it is beneficial to dissipate heat from the LED filament.

[0266] Please refer to Figures 9A to 9D , Figures 9A to 9DSchematic diagram of an LED bulb lamp according to an embodiment of the present application. The LED bulb lamp includes a lamp housing 12 and a lamp head 16 connected to the lamp housing 12. A plurality of LED filaments C1, C2, C3, ……, Cn (n is an integer) are provided inside the lamp housing 12. Each LED filament 100 includes a first electrode and a second electrode. After the LED filament is bent, the vertical distance between the first electrode and the second electrode does not exceed the height of the stem 19. In one embodiment, when the LED filament 100 is not bent, it includes an opposite first end and a second end, and the first end and the second end are used to connect to a power supply component (not shown in the figure) to supply power to the LED chips on the LED filament 100. The length of the LED filament 100 is the distance from the first end to the second end. When the LED filament 100 is bent, the first end and the second end of each LED filament 100 are separated from each other, so that each LED filament 100 is distributed in space. In some embodiments, in the central axis direction of the LED bulb lamp, the vertical distance between the first end of any one LED filament and the first ends of other LED filaments does not exceed 2 cm, and / or the vertical distance between the second end of any one LED filament and the second ends of other LED filaments does not exceed 2 cm. This can enable the first electrodes of the plurality of LED filaments to pass through (or substantially pass through) the first plane, and the second electrodes of the plurality of LED filaments to pass through (or substantially pass through) the second plane. When the LED filaments are electrically connected, the first ends of the plurality of LED filaments 100 are connected together or the second ends are connected together, or the first end of one LED filament 100 is connected to the second end of another LED filament, and the electrical connection method is simple. Compared with the second plane, the first plane is closer to the top of the lamp housing. The first plane and the second plane are separated from each other, and the first plane and the second plane are parallel to each other, or they can also be at a certain angle to each other.

[0267] Each LED filament 100 is distributed in a spiral shape. Each LED filament 100 rotates (spirally) and extends around an axis (such as the central axis of the LED bulb lamp), and the angle by which the second end of the LED filament rotates relative to the first end around the central axis of the LED bulb lamp exceeds 270 degrees (when the LED filament is projected onto a plane along the central axis of the LED bulb lamp, the central angle occupied by the LED filament 100 on this plane is greater than 270 degrees). Preferably, the axes around which at least two LED filaments 100 rotate coincide, that is, they all rotate around the same axis, or the axes around which at least two LED filaments 100 rotate are parallel to each other, or at a certain angle. The LED filament 100 extends in a smooth curve or in a broken line between the first end and the second end around the axis. In one embodiment, the axis around which the above-mentioned LED filament 100 rotates is parallel to the stem 19, or the LED filament 100 rotates and extends around the stem 19.

[0268] There is at least one point on the LED filament C1 whose distance to the stem 19 is equal to or approximately equal to the distance from a point on the LED filament Cn (n≠1) to the stem 19. In one embodiment, in the height direction of the LED bulb, the LED filaments C1, C2, C3, ……, Cn are adjacent in sequence, and the distance from the LED filament C1 to the LED filament C2 is equal to or approximately equal to the distance between the LED filament Cn and the LED filament Cn+1 (n≥2). In the xy plane, the first electrode and / or the second electrode of the LED filaments C1, C2, C3, ……, Cn are located on a circle centered on the stem 19 (or the vertical rod). In the XZ plane or the YZ plane, the projections of the LED filaments intersect with each other, and the projection of a part of the LED filament Cn intersects with the projection of the LED filament Cn+1 (n≥1). In some embodiments, in the XZ plane or the YZ plane, the projection of one LED filament intersects with the projections of other LED filaments. For example, the LED bulb includes four LED filaments C1, C2, C3, C4. In the XZ plane or the YZ plane, the projection of a part of the LED filament C2 intersects with the projections of the LED filaments C1, C3, and C4. Of course, in other embodiments, the projection of a part of the LED filament C2 may intersect with the projections of at least two of the LED filaments C1, C3, and C4.

[0269] Please refer to Figure 10A 、 10B, a fixing part 13 is provided inside the lamp housing 12. A power supply module (not shown in the figure) is connected to the fixing part 131. The fixing part 13 has a first opening 133. The filament body of each filament is located inside the first opening 133. A part of the electrodes 410 / 412 of each LED filament is connected to the fixing part 131 to fix the position of the LED filament 100. Specifically, the fixing part 13 has opposite first connecting part 131 and second connecting part 132. The first electrode 410 is connected to the first connecting part 131, and the second electrode 412 is connected to the second connecting part 132. The first connecting part 131 has opposite first end and second end, and the second connecting part 132 has opposite third end and fourth end. Compared with the second end, the first end of the first connecting part 131 is closer to the third end of the second connecting part 132. When the fixing part 13 is curled, the first end of the first connecting part 131 approaches the second end of the first connecting part 131, and the third end of the second connecting part 132 approaches the fourth end of the second connecting part 132, that is, the first connecting part 131 and the second connecting part 132 are curled in the same direction, and the LED filament 100 is in a straight strip shape. In some embodiments, when the fixing part 13 is curled, the first end of the first connecting part 131 approaches the second end of the first connecting part 131, and the fourth end of the second connecting part 132 approaches the third end of the second connecting part 132, that is, the first connecting part 131 and the second connecting part 132 are curled in opposite directions, and the LED filament 100 is in a bent shape. After the fixing part 13 is curled, the power supply module is electrically connected to the first connecting part 131 and the second connecting part 132 respectively. A carrier 14 is also provided inside the lamp housing 12. After the fixing part 13 is curled, the LED filament 100 is attached to the carrier 14. The material of the carrier 14 is selected as a material with a light transmittance of at least more than 70%. The material of the carrier can be glass or the like to reduce the absorption of the light emitted by the LED filament 100 by the carrier 14. In other embodiments, the carrier can be cylindrical, and the LED filament is fixed to the carrier by means of glue or the like.

[0270] Please refer to Figures 11A to 11B , a supporting unit is provided on the core column 19. The supporting unit is perpendicular to the core column 19 (or the central axis of the LED bulb lamp), and the supporting unit extends towards the top of the lamp housing 12 along the central axis of the LED bulb lamp. A plurality of supporting parts 15 are provided on the supporting unit. A second opening 151 is provided on the supporting part 15. The height of the LED filament 100 is less than the width of the LED filament 100. The LED filament 100 can first enter the supporting part 15 obliquely through the second opening 151. Since the minimum distance of the second opening 151 is greater than the width of the LED filament 100, the LED filament 100 can be prevented from coming out of the supporting part 15, thereby fixing the shape of the LED filament 100.

[0271] Please refer to Figure 12 , Figure 12Schematic diagram of the light emission spectrum of an LED bulb lamp according to an embodiment of the present application. In this embodiment, the LED bulb lamp can be any of the LED bulb lamps disclosed in the previous embodiments, and a single LED filament disclosed in each of the previous embodiments is provided in this LED bulb lamp. By measuring the light emitted by the LED bulb lamp with a spectrometer, the spectrum schematic diagram as shown in Figure 12 can be obtained. From this spectrum schematic diagram, it can be seen that the spectrum of the LED bulb lamp is mainly distributed between wavelengths of 400 nm and 800 nm, and three peaks P1, P2, and P3 appear at three places within this range. Peak P1 is approximately between wavelengths of 430 nm and 480 nm, peak P2 is approximately between wavelengths of 580 nm and 620 nm, and peak P3 is approximately between wavelengths of 680 nm and 750 nm. In terms of intensity, the intensity of peak P1 is less than the intensity of peak P2, and the intensity of peak P2 is less than the intensity of peak P3. As shown in Figure 12 , such a spectrum distribution is close to the spectrum distribution of a traditional incandescent filament lamp and also close to the spectrum distribution of natural light. In a certain embodiment, the schematic diagram of the light emission spectrum of a single LED filament is as shown in Figure 13 . From this spectrum schematic diagram, it can be seen that the spectrum of the LED bulb lamp is mainly distributed between wavelengths of 400 nm and 800 nm, and three peaks P1, P2, and P3 appear at three places within this range. Peak P1 is approximately between wavelengths of 430 nm and 480 nm, peak P2 is approximately between wavelengths of 480 nm and 530 nm, and peak P3 is approximately between wavelengths of 630 nm and 680 nm. In terms of intensity, the intensity of peak P1 is less than the intensity of peak P2, and the intensity of peak P2 is less than the intensity of peak P3. As shown in Figure 13 , such a spectrum distribution is close to the spectrum distribution of a traditional incandescent filament lamp and also close to the spectrum distribution of natural light.

[0272] Please refer to Figure 14 , Figure 14 is the light emission spectrum diagram of an LED bulb lamp according to an embodiment of the present application. It can be seen from the figure that the spectrum of the LED bulb lamp is distributed between wavelengths of 400 nm and 800 nm and has a similarity as shown in Figure 13The three peaks P1’, P2’, and P3’ shown have peak P1’ approximately between wavelengths of 430 nm and 480 nm, peak P2’ approximately between wavelengths of 480 nm and 530 nm, and peak P3’ approximately between wavelengths of 630 nm and 680 nm. In terms of intensity, the intensity of peak P1’ is less than that of peak P2’, and the intensity of peak P2 is less than that of peak P3’. The difference is that the intensity of P1’ is greater than P1, and the full width at half maximum of peak P3’ is greater than P3. This LED bulb has an average color rendering index Ra (R1 - R8) greater than 95, a saturated red (R9) greater than or equal to 90, and the luminous efficacy (Eff) of the LED filament is greater than or equal to 100 lm / w.

[0273] Figures 17 - 20 The following shows the light distribution curves of LED bulbs of different embodiments. Please combine Figure 15 From the figure, it can be seen that the light emitted by the LED bulb is approximately symmetrically distributed around the optical axis L. The light emitted after the LED bulb is lit has a butterfly-shaped light distribution curve and a relatively wide light distribution. If the lamp head is upward and the lamp housing is downward (as shown in Figure 16), then the downward direction is defined as 0 degrees. Curve L1 is the light intensity distribution curve of the 0-degree and 180-degree sections (C0 / 180), and curve L2 is the light intensity distribution curve of the 90-degree and 270-degree sections (C90 / 270). C0 / 180 and C90 / 270 are respectively axisymmetric about the center axis of the LED bulb. The LED bulb is light distribution symmetric in the 0-degree and 180-degree sections and / or in the 90-degree and 270-degree sections. Since when the LED bulb is lit, within different angular ranges, the filament lengths on the two sections are different or the number of LED chips is different, etc., the luminous intensity on curve L1 is greater than that on curve L2 in some angular ranges, and the luminous intensity on curve L1 is less than that on curve L2 in some other angular ranges. As a result, curves L1 and L2 partially overlap, that is, there is at least one point on curve L1 that lies on curve L2.

[0274] Specifically, in the 0-degree and 180-degree sections and the 90-degree and 270-degree sections, within a certain angular range, the luminous intensity of curve L1 is greater than that of curve L2 (i.e., curve L1 is on the outer periphery of curve L2). Within this angular range, the length of the LED filament corresponding to curve L1 is greater than the length of the LED filament corresponding to curve L2, or the number of LED chips corresponding to curve L1 is greater than the number of LED chips corresponding to curve L2. For example Figure 17 within the range of 100 degrees to 130 degrees, Figure 18 within the range of 30 degrees to 80 degrees, Figure 19 within the range of 30 degrees to 160 degrees, Figure 20 within the range of 70 degrees to 80 degrees.

[0275] On a plane that is symmetric about the central axis of the LED bulb lamp, a part of the top layer of the LED filament faces outward, and a part of the carrier layer faces outward. On the cross-section of the central axis (or optical axis) of the LED chip, when the carrier layer faces outward, the shortest distance from the carrier layer to the lamp housing is less than the shortest distance from the top layer to the lamp housing; when the top layer faces outward, the shortest distance from the top layer to the lamp housing is less than the shortest distance from the carrier layer to the lamp housing. The light emitted by the LED filament is partly emitted from the top layer and partly emitted from the carrier layer. The luminous flux of the light emitted through the top layer is greater than the luminous flux of the light emitted through the carrier layer. The plane that is symmetric about the central axis of the LED bulb lamp (such as the YZ plane) has light emitted from both the top layer and the base layer. If some of these planes only have light emitted from the top layer or from the base layer, it will cause uneven light distribution of the LED bulb lamp and affect the light output effect of the LED bulb lamp.

[0276] In one embodiment, when any LED filament in the LED bulb lamp is bent, the light-emitting directions of at least two LED chips in one LED filament are different. If there are more than two LED filaments in the LED bulb lamp, the light-emitting direction of at least one LED chip in one LED filament is different from the light-emitting direction of at least one LED chip in another LED filament. The light-emitting direction of the LED chip will affect the luminous flux in different angular ranges of the LED bulb lamp. Since the light-emitting directions of multiple LED chips in the LED filament are different, light will be emitted in multiple angular ranges of the LED bulb lamp, preventing the appearance of dark areas in some angular ranges of the LED bulb lamp. For example Figures 14 to 17 in the figure, there is no light near the lamp head of the LED bulb lamp, and light is emitted in other areas.

[0277] In one embodiment, some LED bulb lamps have relatively less luminous flux distribution in the range of 0 degrees to 30 degrees. For example, the total luminous flux in the range of 0 degrees to 30 degrees is 3% to 20% of the luminous flux of the LED bulb lamp. When the LED filaments in these LED bulb lamps are bent around the central axis of the LED bulb lamp, the LED filaments are relatively far from the central axis (or the stem) of the LED bulb lamp, which will result in less light output in the central axis area of the LED bulb lamp. In some embodiments, the distances from different regions of the LED filaments to the central axis (or the stem) of the LED bulb lamp are different. A part of the LED filaments is close to the central axis (or the stem) of the LED bulb lamp, and a part of the LED filaments is far from the central axis of the LED bulb lamp. Further, a part of the LED chips is close to the central axis (or the stem) of the LED bulb lamp, and a part of the LED chips is far from the central axis of the LED bulb lamp. If a part of the LED filaments is relatively close to the central axis of the LED bulb lamp, the distance from this part of the LED filaments (top layer or carrier layer) to the central axis (or the stem) of the LED bulb lamp is 2 - 15 mm, or the length of the cantilever is 2 - 15 mm. On the one hand, the heat generated by the LED filaments is not easily concentrated; on the other hand, the luminous flux in the light emission direction of the LED bulb lamp increases, so that the spatial distribution of the light output by the LED bulb lamp is uniform.

[0278] In some embodiments, at least part of the LED filaments intersect with the central axis (or the stem) of the LED bulb lamp. The intersection can be, for example, that part of the LED filaments pass through the top of the stem, and the distance from part of the LED filaments to the stem is about 0 (0 - 5 mm), or the LED filaments and the stem can be regarded as a line respectively, and there is an intersection or overlap with the central axis of the LED bulb lamp. The LED filaments increase the luminous flux in the central axis area of the LED bulb lamp. The luminous flux in the range of 0 degrees to 30 degrees is 20% to 50% of the total luminous flux of the LED bulb lamp, preventing the formation of a dark area in the light emission direction of the central axis of the LED bulb lamp. Further, at least one or more LED chips are included in the part of the LED filaments that intersect with the central axis (or the stem) of the LED bulb lamp to increase the luminous flux in the central axis area of the LED bulb lamp.

[0279] In some embodiments, at least on a plane (such as the XY plane, YZ plane or YZ plane), the LED filaments in the LED bulb lamp are symmetric about the central axis (or the stem) of the LED bulb lamp. Further, at least on a plane, the length of the LED filaments is symmetric about the central axis (or the stem) of the LED bulb lamp. Still further, at least on a plane, the number of LED chips in the LED filaments is symmetric about the central axis (or the stem) of the LED bulb lamp. When the LED filaments are symmetrically distributed, the light intensity distributions of the LED bulb lamp on the 0 - degree and 180 - degree sections and the 90 - degree and 270 - degree sections are relatively uniform, and the areas enclosed by the curve L1 and the curve L2 are approximately the same. For example, Figure 17As shown in Fig. 18, the light distribution of the LED bulb lamp is relatively uniform.

[0280] The beam angle of the LED bulb lamp at the 0° and 180° sections is α, and the beam angle of the LED bulb lamp at the 90° and 270° sections is β. The absolute value of the difference between α and β is less than 50°. Because if the difference between α and β is large, the positions where the maximum light intensity appears on the two sections will be far apart, the light and dark levels will be more obvious, and the light output uniformity of the LED bulb lamp will be poor. Further, the absolute value of the difference between α and β is less than 30°, and the LED bulb lamp has better light output uniformity. Further, the absolute value of the difference between α and β is less than 10°, and the light distribution of the LED bulb lamp is uniform. The definition of the beam angle can be specified by the International Commission on Illumination (CIE, Europe) or the Illuminating Engineering Society (IES, USA). Specifically, if specified according to the Illuminating Engineering Society (IES, USA), the average beam angle (the average of α and β) of the LED bulb lamp is greater than 100°, and the light distribution is relatively wide. In this embodiment, the beam angle of the LED bulb lamp is defined as the included angle between the two sides at 50% of the normal light intensity.

[0281] The distance between the highest point and the lowest point of the LED filament in the LED bulb lamp accounts for 50% - 80% of the height of the lamp housing (the distance from the connection between the lamp housing and the lamp head to the top of the lamp housing), and light penetrates through most areas of the lamp housing, so the light distribution is relatively wide. If the LED bulb lamp includes multiple LED filaments, the highest point and the lowest point of the above-mentioned LED filament are the highest point and the lowest point of any one LED filament.

[0282] Figure 21 It is a circuit diagram of a constant current circuit according to an embodiment of the present invention. According to the general habit of circuit diagrams, the optional parameters of each component are marked in the figure, and the unit is the international standard measurement unit. In the following description, for the sake of simplicity, the first resistor R1 is referred to as R1, and the same applies to other components.

[0283] According to Figure 21 the circuit shown, after power-on, the voltage at point A is the voltage division of R4 across R3 and R4. Therefore, the current between the drain and source of M1 rises, making Vbe large enough to turn on Q1, and then the voltage at point A is pulled down, resulting in a decrease in the current between the drain and source of M1. Since R1 is very small, Vbe cannot reach the conduction voltage of Q1, so Q1 turns off. When Q1 turns off, the voltage at point A returns to the voltage division of R4 across R3 and R4, so the current between the drain and source of M1 rises again, and then the above process is repeated. Eventually, M1 is kept on, and the current IR1 flowing through R1 remains approximately equal to the ratio of Vbe to R1. It can be seen that in this way, the current on the load D5 is made constant.

[0284] Figure 22 The structure of the circuit shown inFigure 21 Basically the same, except that Figure 22 includes a positive temperature coefficient thermistor PTC resistor. The voltages of some points and the currents in some branches are marked in the figure. The current flowing through the PTC, IPTC = (Vin - Vbe) / PTC. Since the current input to the base of Q1 is almost zero, so IPTC = IR2, and IR2 = (Vbe - VB) / R2, where VB represents the voltage at point B. Therefore, (Vin - Vbe) / PTC = (Vbe - VB) / R2, and in this formula, PTC represents the resistance value of the PTC resistor. Transforming according to this formula gives VB = Vbe - (Vin - Vbe)R2 / PTC. From Figure 22 it is known that VB = ID5×R1. Therefore, ID5×R1 = Vbe - (Vin - Vbe)R2 / PTC, and thus formula 1 is obtained:

[0285] ID5 = Vbe / R1 - [(Vin - Vbe)×R2] / (PTC×R1).

[0286] It can be seen from formula 1 that the load current ID5 is also affected by the resistance of the PTC. Due to the physical properties of the triode, the voltage Vbe at its base will decrease when the temperature rises. It can be seen from formula 1 that when Vbe decreases, ID5 will decrease, that is, the load current will decrease, affecting the lighting of the lamp. On the other hand, the PTC will increase when the temperature rises. It can be seen from formula 1 that when the PTC increases, ID5 will also increase, which helps to offset the fluctuation of the load current caused by the decrease of Vbe.

[0287] According to formula 1, if the PTC resistor is replaced with a negative temperature coefficient thermistor, it will cause ID5 to increase when the temperature decreases, that is, the low-temperature protection function of the lamp is realized. In addition, it can also be seen from formula 1 that R1 directly affects ID5, that is, R1 directly affects the brightness of the lamp. Therefore, when the power supply voltage remains unchanged, the magnitude of the load current can be set by selecting the value of R1.

[0288] According to Figure 21 and Figure 22 In the shown circuit, M1 is used as the main switching element, and its current is affected by the negative feedback loop composed of R1, R2, and Q1. And Q1 is used as the secondary switching element, which is turned on or off under the action of the current of M1, and finally the conduction current of M1 is maintained at a fixed level, thus realizing a constant current circuit for the load. Figure 21 and Figure 22 are only for examples, and there can also be other circuit topologies, such as Figure 23 , Figure 23 is the circuit diagram of the third constant current circuit according to the embodiment of the present invention.

[0289] According to Figure 23For the circuit shown, in a preferred manner, i.e., when a PTC1 (or an NTC resistor) is added, similar to the previous analysis, after power-on, the conduction current of M1 increases, causing Q3 to conduct, and the conduction of Q3 in turn causes the conduction current of M1 to decrease, also forming a negative feedback similar to that in Figure 24 and Figure 22 , which enables M1 to maintain a constant conduction current state and makes the current flowing through the load D1 constant.

[0290] In the technical solution of the embodiment of the present invention, other types of switching devices can also be used for each switching element. In addition to using a DC voltage source, the power supply can also be a rectifier circuit, so that the external AC input (usually the mains) can be converted into DC. In addition, a capacitor can be connected in parallel with the fourth resistor R4, so that the voltage at point A gradually increases during power-on, realizing the function of delayed startup.

[0291] According to the technical solution of the embodiment of the present invention, a main switching element and a negative feedback circuit are used to make the current flowing through the main switching element a constant value, thereby realizing a constant current circuit. This method can realize a constant current circuit only by using fewer discrete components and does not involve electromagnetic compatibility problems. In the specific circuit structure, PTC or NTC can also be used to improve the temperature drift phenomenon. When this constant current circuit is applied to a lamp, it occupies a small volume and has stable light emission.

[0292] Refer to Figure 24 which is a schematic block diagram of the circuit of an LED lamp according to an embodiment of the present application. In this embodiment, the LED lamp includes a constant current driving circuit 10a, a shunt circuit 20a, and an LED module 30a. The constant current driving circuit 10a is a constant current source that provides a constant current. The LED module 30a includes LED components 31a and 32a. The LED components 31a and 32a are electrically connected to the shunt circuit 20a. The shunt circuit 20a is used to receive the constant current of the constant current driving circuit 10a and distribute the current to the LED components 31a and 32a. In this embodiment, an LED component is one light-emitting diode or multiple series-connected light-emitting diodes.

[0293] In some embodiments, the LED components 31a and 32a are configured with different color temperatures. By adjusting the current flowing through the LED components 31a and 32a, the brightness of the LED components 31a and 32a can be adjusted, and by adjusting the brightness ratio of the LED components 31a and 32a, the adjustment of the color temperature can be realized.

[0294] In some embodiments, the LED components 31a and 32a are configured with different colors.

[0295] In some embodiments, the number of light-emitting diodes included in the LED components 31a and 32a is different.

[0296] Through the configuration method of the above embodiments, only one constant current driving circuit is required to control at least two LED components, realizing the function of adjusting the color temperature or color. Especially when the number of light-emitting diodes included in the LED components is different, the current adjustment of different LED components can still be achieved.

[0297] Reference Figure 25A FIG. is a schematic circuit diagram of an LED lamp according to an embodiment of the present application. In this embodiment, the constant current driving circuit 10a includes a constant current source A1, the LED component 31a includes a component D1, the LED component 32a includes an LED component D2, the shunt circuit 20a includes a triode Q1, and resistors R1 and R2. The anode of the LED component D1 is electrically connected to the anode of the LED component D2 and electrically connected to the first output terminal of the constant current source A1. The cathode of the LED component D1 is electrically connected to the collector of the triode Q1, the emitter of the triode Q1 is electrically connected to the common ground terminal, the base of the triode Q1 is electrically connected to the first pin of the resistor R2, and the second pin of the resistor R2 is electrically connected to the first pin of the resistor R1 and the cathode of the LED component D2. The second pin of the resistor R1 is electrically connected to the common ground terminal. The second output terminal of the constant current source A1 is electrically connected to the common ground terminal.

[0298] In this embodiment, the LED components D1 and D2 include one light-emitting diode or a plurality of serially connected light-emitting diodes (i.e., the LED chips in the foregoing embodiments).

[0299] The operation principle of the shunt circuit 20a is described below. In this embodiment, the constant current source A1 provides a constant current I1. After being shunted by the shunt circuit 20a, the current flowing through the LED component D1 is ID1, and the current flowing through the LED component D2 is ID2. The current flowing through the resistor R1 is IR1, and the current flowing through the resistor R2 is IR2. The voltage at the base of the triode Q1 is Vbe, and the current at the emitter of the triode Q1 is IQ1. The currents satisfy the following relationships:

[0300] I1 = ID1 + ID2

[0301] ID2 = IR1 + IR2

[0302] IQ1 = ID1 + IR2

[0303] In this embodiment, since the current of IR2 is small and can be ignored, therefore

[0304] ID2 ≈ IR1

[0305] IQ1 ≈ ID1

[0306] IR1 ≈ Vbe / R1

[0307] When ID2 has an increasing trend, VR1 increases, IR2 increases. According to the amplification principle of the triode, ID1 increases. Since the sum of ID1 and ID2 is a constant value I1, when ID1 increases, ID2 decreases. Therefore, when ID2 has an increasing trend, through the adjustment of the shunt circuit 20a, the increasing trend of ID2 is suppressed, making ID2 tend to a stable value. Similarly, when ID2 has a decreasing trend, VR1 decreases, IR2 decreases. According to the amplification principle of the triode, ID1 decreases. Since ID1 + ID2 = I1, when ID1 decreases, ID2 increases. Therefore, when ID2 has a decreasing trend, through the adjustment of the shunt circuit 20a, the decrease of ID2 is suppressed, making ID2 tend to a stable value.

[0308] ID2 ≈ Vbe / R1

[0309] ID1 = I1 - ID2

[0310] In this embodiment, Vbe is a constant value, approximately 0.7V. By adjusting the size of the resistor R1, the magnitudes of the current ID1 and the current ID2 can be adjusted to achieve the purpose of adjusting the brightness of the LED components D1 and D2.

[0311] In some embodiments, the number of light-emitting diodes included in the LED component D1 is less than or equal to the number of light-emitting diodes included in the LED component D2.

[0312] In some embodiments, the LED components D1 and D2 are configured to have different colors or color temperatures.

[0313] In some embodiments, the triode Q1 can be replaced by a field-effect transistor without affecting the technical effects to be achieved by this application.

[0314] Reference Figure 25B is a schematic circuit diagram of an LED lamp according to another embodiment of this application. The circuit structure of the LED lamp in this embodiment is the same as that of Figure 25ASimilar to the embodiments described above, in this embodiment, the LED module 30a further includes an LED component D3, and the shunt circuit 20a further includes a triode Q2 and resistors R3 and R4. The anode of the LED component D1 is electrically connected to the anodes of the LED component D2 and the LED component D3 and is electrically connected to the first output terminal of the constant current source A1. The cathode of the LED component D1 is electrically connected to the collector of the triode Q1. The emitter of the triode Q1 is electrically connected to the second pin of the resistor R1, and its base is electrically connected to the first pin of the resistor R2. The second pin of the resistor R2 is electrically connected to the cathode of the LED component D2 and the first pin of the resistor R1. The collector of the triode Q2 is electrically connected to the second pin of the resistor R1, its emitter is electrically connected to the common ground terminal, and its base is electrically connected to the first pin of the resistor R4. The second pin of the resistor R4 is electrically connected to the cathode of the LED component D3 and the first pin of the resistor R3. The second pin of the resistor R3 is electrically connected to the common ground terminal. The second output terminal of the constant current source A1 is electrically connected to the common ground terminal.

[0315] In this embodiment, the principle of the shunt circuit for adjusting the current of the three LED components is the same as that of Figure 25A the embodiments described above. Different from them, in this embodiment, an additional LED component D3 is added. In this embodiment, the current relationship satisfies the following relational expressions:

[0316] I1 = ID1 + ID2 + ID3

[0317] ID3 ≈ IR3

[0318] ID2 ≈ IR1

[0319] ID1 ≈ IQ1

[0320] In this embodiment, IR2 and IR4 can be ignored.

[0321] Therefore:

[0322] ID3 ≈ Vbe / R3

[0323] ID2 ≈ Vbe / R1

[0324] ID1 = I1 - ID2 - ID3

[0325] In this embodiment, Vbe is a constant value, approximately 0.7V. By adjusting the resistance values of the resistors R1 and R3, the magnitudes of the currents ID2, ID3, and ID1 can be adjusted, thereby adjusting the brightness of the LED components D1, D2, and D3.

[0326] In this embodiment, the number of diodes included in the LED component D1 is less than or equal to the number of light-emitting diodes included in the LED component D2; the number of light-emitting diodes included in the LED component D2 is less than or equal to the number of light-emitting diodes included in the LED component D3.

[0327] In some embodiments, the LED components D1, D1, D3 are configured to have different colors or color temperatures.

[0328] In some embodiments, the triodes Q1 and Q2 can be replaced by field-effect transistors without affecting the technical effects to be achieved by this application.

[0329] Through the configuration method of the above embodiments, only one constant-current drive circuit is needed to control three LED components, realizing the function of adjusting the color temperature or color. Especially when the number of light-emitting diodes included in the LED components is different, the current adjustment of different LED components can still be achieved.

[0330] Reference Figure 25C is a schematic circuit diagram of an LED lamp according to another embodiment of this application. The circuit structure of the LED lamp in this embodiment is similar to that of Figure 25A the described embodiment. The difference is that the triode used in the shunt circuit 20a in this embodiment is a PNP-type triode, while Figure 25A the triode used in the described embodiment is an NPN-type triode. In this embodiment, the constant-current drive circuit 10a includes a constant current source A1, the LED module 30a includes LED components D1 and D2, and the shunt circuit 20a includes triode Q1 and resistors R1, R2. The emitter of triode Q1 is electrically connected to the first pin of resistor R1 and the first output terminal of the constant current source A1, its collector is electrically connected to the anode of the LED component D1, and its base is electrically connected to the first pin of resistor R2. The second pin of resistor R2 is electrically connected to the second pin of resistor R1 and the anode of the LED component D2. The cathodes of the LED component D1 and the LED component D2 are electrically connected and electrically connected to the common ground terminal. The second output terminal of the constant current source A1 is electrically connected to the common ground terminal.

[0331] In this embodiment, the operation principle of the shunt circuit 20a is similar to that of Figure 25A , 25B the described embodiment and will not be elaborated here.

[0332] In this embodiment, since the current of IR2 is small, it can be ignored. Its current satisfies the following relationship:

[0333] ID2≈Vbe / R1

[0334] ID1=I1-ID2

[0335] By adjusting the size of the resistor R1, the magnitudes of the currents ID1 and ID2 can be adjusted, and further the brightness of the LED components D1 and D2 can be adjusted.

[0336] In some embodiments, the number of light-emitting diodes included in the LED component D1 is less than or equal to the number of light-emitting diodes included in the LED component D2.

[0337] In some embodiments, the LED components D1 and D2 are configured to have different colors or color temperatures.

[0338] In some embodiments, the triode Q1 can be replaced with a field-effect transistor without affecting the technical effects to be achieved by this application.

[0339] Through the configuration manner of the above embodiments, only one constant-current driving circuit can be used to control two LED components, and the function of adjusting the color temperature or color can be realized. Especially when the number of light-emitting diodes included in the LED components is different, the current adjustment of different LED components can still be achieved.

[0340] Through the elaboration of the above embodiments, those skilled in the art of this industry can reasonably expand to perform shunt adjustment on multiple LED components, not limited to two or three.

[0341] The "one LED filament" and "one strip of LED filament" referred to in this application refer to the structure formed by connecting the aforementioned conductor segments and LED segments together or only composed of LED segments (or LED chip units), having the same and continuous light conversion layer (including the same and continuously formed top layer or bottom layer), and only having two conductive electrodes electrically connected to the bulb conductive bracket at both ends. A structure that conforms to the above description is the single LED filament structure referred to in this application.

[0342] This application has been disclosed above with preferred embodiments. However, those skilled in the art should understand that this embodiment is only used to depict some implementation manners of this application and should not be construed as a limitation. It should be noted that all equivalent changes, substitutions, or reasonable combinations between embodiments (especially the LED filament embodiments, combined into the bulb embodiment of Figure 4) should be considered as falling within the scope supported by this application's specification. Therefore, the protection scope of this application shall be subject to the scope defined by the appended claims.

Claims

1. An LED filament, characterized in that, the LED filament comprises: an LED chip, a light conversion layer, a laminate and electrodes, and the adjacent LED chips, the LED chip and the electrodes are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrodes, the laminate is disposed on the outer surface of the light conversion layer, and the laminate covers at least a part of the surface of the light conversion layer, wherein the laminate comprises a colorant, and the surface of the LED filament presents white when not lit.

2. The LED filament according to claim 1, characterized in that: the hardness of the laminate is less than that of the light conversion layer.

3. The LED filament according to claim 1, characterized in that: the hardness of the laminate is greater than that of the light conversion layer.

4. The LED filament according to claim 1, characterized in that: the laminate includes a photoreactive substance, after the LED chip emits light, it undergoes a first light conversion through the light conversion layer, and then undergoes a second light conversion through the photoreactive substance in the laminate.

5. The LED filament according to claim 4, characterized in that: the LED filament has a first color when not lit and a second color different from the first color when lit.

6. The LED filament according to claim 1, characterized in that: the laminate is made of silicone or a material with silicone as the main body. When directly using silicone, the laminate presents white due to the color of the silicone itself.

7. The LED filament according to claim 1, characterized in that: the LED filament has bendable sections and non-bendable sections in the length direction, and the total length of the bendable sections is less than the total length of the non-bendable sections.

8. The LED filament according to claim 7, characterized in that: the non-bendable sections are the parts including the LED chips or electrodes in the length direction of the LED filament.

9. The LED filament according to claim 7, characterized in that: the bendable sections are the parts including only the light conversion layer or wires in the length direction of the filament.

10. The LED filament according to claim 1, characterized in that: there are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

11. The LED filament according to claim 10, characterized in that: the adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

12. An LED filament, characterized in that, the LED filament comprises: an LED chip, a light conversion layer, a laminate and electrodes, and the adjacent LED chips, the LED chip and the electrodes are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrodes, the light conversion layer comprises a top layer and a bearing layer, and the color of the upper surface of the top layer is different from that of the lower surface of the bearing layer, and the LED filament presents two different colors when not lit.

13. The LED filament according to claim 12, characterized in that: The length direction of the LED filament has a bendable section and a non-bendable section, and the total length of the bendable section is less than the total length of the non-bendable section.

14. The LED filament according to claim 13, wherein: The non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

15. The LED filament according to claim 13, wherein: The bendable section is the part of the filament in the length direction that only includes the light conversion layer or the wire.

16. The LED filament according to claim 12, wherein: There are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

17. The LED filament according to claim 16, wherein: The adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

18. An LED bulb lamp, characterized in that it includes: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column and an LED filament. The LED filament includes an LED chip, a light conversion layer, a layer-like body and an electrode. The adjacent LED chips, the LED chip and the electrode are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrode. The layer-like body is arranged on the outer surface of the light conversion layer, and the layer-like body at least covers a part of the surface of the light conversion layer. Among them, the layer-like body includes a colorant, and the surface of the LED filament presents gray when not lit.

19. The LED bulb lamp according to claim 18, wherein: The hardness of the layer-like body is less than that of the light conversion layer.

20. The LED bulb lamp according to claim 18, wherein: The hardness of the layer-like body is greater than that of the light conversion layer.

21. The LED bulb lamp according to claim 18, wherein: The layer-like body includes a photoreactive substance. After the LED chip emits light, it undergoes a first light conversion through the light conversion layer, and then undergoes a second light conversion through the photoreactive substance in the layer-like body.

22. The LED bulb lamp according to claim 21, wherein: The LED filament has a first color when not lit and a second color different from the first color when lit.

23. The LED bulb lamp according to claim 18, wherein: The layer-like body adopts a material with silicone or silicone as the main body. When directly using silicone, the layer-like body is white due to the color of the silicone itself.

24. The LED bulb lamp according to claim 18, wherein: The length direction of the LED filament has a bendable section and a non-bendable section, and the total length of the bendable section is less than the total length of the non-bendable section.

25. The LED bulb lamp according to claim 24, wherein: The non-bendable section is the part of the LED filament in the length direction that includes the LED chip or the electrode.

26. The LED bulb lamp according to claim 24, wherein: The bendable section is the part that only includes the light conversion layer or the wire in the length direction of the filament.

27. The LED bulb lamp according to claim 18, characterized in that: There are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

28. The LED bulb lamp according to claim 27, characterized in that: The adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

29. An LED bulb lamp, characterized in that it includes: a lamp housing, a lamp head connected to the lamp housing, at least two conductive brackets arranged in the lamp housing, a cantilever, a core column and an LED filament. The LED filament includes an LED chip, a light conversion layer, a layer-like body and an electrode. The adjacent LED chips, the LED chip and the electrode are electrically connected to each other; the light conversion layer wraps the LED chip and at least a part of the electrode. The light conversion layer includes a top layer and a bearing layer, and the color of the upper surface of the top layer is different from that of the lower surface of the bearing layer. The LED filament presents two different colors when not lit.

30. The LED bulb lamp according to claim 29, characterized in that: The length direction of the LED filament has a bendable section and an un-bendable section, and the total length of the bendable section is less than the total length of the un-bendable section.

31. The LED bulb lamp according to claim 30, characterized in that: The un-bendable section is the part that includes the LED chip or the electrode in the length direction of the LED filament.

32. The LED bulb lamp according to claim 30, characterized in that: The bendable section is the part that only includes the light conversion layer or the wire in the length direction of the filament.

33. The LED bulb lamp according to claim 29, characterized in that: There are multiple LED chips, and the multiple LED chips are arranged in two columns on the LED filament.

34. The LED bulb lamp according to claim 33, characterized in that: The adjacent LED chips are arranged staggeredly in the width direction of the LED filament, and the two columns of LED chips are arranged along the length direction of the LED filament.

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