CN213452941U

CN213452941U - LED filament and LED bulb

Info

Publication number: CN213452941U
Application number: CN202021362430.5U
Authority: CN
Inventors: 江涛; 徐卫洪; 斋藤幸广; 鳗池勇人; 熊爱明; 徐俊锋; 陈易庆
Original assignee: Jiaxing Super Lighting Electric Appliance Co Ltd
Current assignee: Jiaxing Super Lighting Electric Appliance Co Ltd
Priority date: 2017-12-26
Filing date: 2018-12-26
Publication date: 2021-06-15
Anticipated expiration: 2028-12-26
Also published as: CN214147468U; CN214663776U

Abstract

The application discloses LED filament, LED filament is located a plane rectangular coordinate system (X, Y), wherein the X axle is on a parallel with the length direction of LED filament, LED filament includes: the LED chip units are arranged at different positions in the Y-axis direction; and the two electrodes are configured corresponding to the LED chip units and are electrically connected with the LED chip units through leads. The application also discloses an LED bulb lamp comprising the LED filament. The utility model discloses a set up the position of two adjacent LED chip units, can make the LED filament can not harm the chip when conductor department buckles to improve product quality's stability, but also improve the heat dispersion of LED filament.

Description

LED filament and LED bulb

The utility model discloses the application is that 2018 12 months 26 submit the branch case application of the chinese patent office, application number 201822198239.0, invention name "LED filament and LED ball bubble lamp".

Technical Field

The utility model relates to the field of lighting, concretely relates to LED filament and LED ball bubble lamp of using thereof.

Background

Incandescent light bulbs have been widely used for decades for illumination in homes and businesses, however, incandescent light bulbs are generally less efficient in their energy usage, with approximately 90% of the energy input going to be dissipated as heat. And because incandescent bulbs have a very limited life (about 1,000 hours), they need to be replaced often. These conventional lamps are gradually replaced by other more efficient lamps, such as fluorescent lamps, high intensity discharge lamps, Light Emitting Diodes (LEDs), etc. Among these lamps, LED lamps are the most attractive lighting technology. The LED lamp has the advantages of long service life, small volume, environmental protection and the like, so the application of the LED lamp is continuously increased.

In recent years, an LED bulb lamp with an LED filament is available on the market. The LED bulb lamp using the LED filament as a luminous source in the market at present still has the following problems to be improved:

first, an LED hard filament is used having a substrate (e.g., a glass substrate) and a plurality of LED chips on the substrate. However, the lighting effect of the LED bulb lamp can be better only by combining a plurality of hard filaments, and the lighting effect of a single hard filament cannot meet the general demand in the market. Traditional ball bubble lamps and lanterns have the tungsten filament, can produce even light-emitting because the nature of the nature bendable of tungsten filament, however the effect of this kind of even light is difficult to reach to the hard filament of LED. There are many reasons why it is difficult to achieve this effect for the LED filament, except for the foregoing inflexibility, one of them is that the substrate can block the light emitted by the LED, and the light generated by the LED is a point light source, which can lead to light concentration. In contrast, a uniform light distribution results in a uniform illumination effect, while a concentrated light distribution results in an uneven and concentrated illumination effect.

In addition, there is also a soft filament of LED, which is similar to the above filament structure, and the glass substrate is partially replaced by a flexible substrate (hereinafter referred to as FPC), so that the filament can have a certain degree of bending. However, the soft filament made of the FPC has a thermal expansion coefficient different from that of the silica gel coating the filament, and the displacement and even the degumming of the LED chip are caused by long-term use; or the FPC is not favorable for flexible change of the process conditions and the like. In addition, the filament structure has the challenge to the stability of the metal routing between the chips when buckling, and when the arrangement of the chips in the filament is meticulous, if the adjacent LED chips are connected in a metal routing mode, the stress is easily over concentrated at the specific part of the filament due to the bending of the filament, so that the metal routing for connecting the LED chips is damaged or even broken.

Patent No. CN202252991U discloses that the upper and lower surfaces of a chip or the periphery thereof are coated with fluorescent powder respectively, the chip is fixed on a flexible PCB and is bonded and packaged by an insulating glue, the insulating glue is epoxy resin glue; the electrodes of the chip are connected with the circuit on the flexible PCB board through gold wires; the flexible PCB board is transparent or semitransparent, and the flexible PCB board is printed circuit preparation on polyimide or polyester film base plate and forms, adopts the flexible PCB board to replace aluminium base board support lamp radiating part, improves the heat dissipation. Patent publication No. CN105161608A discloses an LED filament light-emitting strip and a manufacturing method thereof, in which non-overlapping chip light-emitting surfaces are arranged in a face-to-face manner, so as to improve light-emitting uniformity and heat dissipation. Patent publication No. CN103939758A discloses that a transparent and heat-conducting heat dissipation layer is formed between the bearing surface of the carrier and the bonding surface of the LED chip for heat exchange with the LED chip. The aforesaid patent adopts PCB board, adjustment chip to arrange or form the heat dissipation layer respectively, though can improve the filament heat dissipation to a certain extent, nevertheless because of the radiating efficiency is low, and the heat is easy to be gathered. Finally, patent publication No. CN204289439U discloses a full-circle light-emitting LED filament, which includes a substrate mixed with phosphor, electrodes disposed on the substrate, at least one LED chip mounted on the substrate, and a packaging adhesive covering the LED chip. Through the base plate that contains the silicone resin of phosphor powder formed, avoided glass or sapphire as the cost of base plate, use the filament of base plate preparation has avoided glass or sapphire to the influence of chip light-emitting, has realized 360 degrees light-emitting, and light-emitting homogeneity and light efficiency improve greatly. However, the substrate is formed of silicone resin, which has a disadvantage of poor heat resistance.

SUMMERY OF THE UTILITY MODEL

It is specifically noted that the present disclosure may actually include one or more of the presently claimed or as yet unclaimed versions, and that the various versions possible herein may be collectively referred to herein as "the present invention" in the course of writing the specification in order to avoid confusion due to unnecessary distinction between such possible versions.

This summary describes many embodiments relating to the "present invention". However, the term "present invention" is used merely to describe some embodiments disclosed in this specification (whether or not in the claims), and not a complete description of all possible embodiments. Certain embodiments of various features or aspects described below as "the present invention" may be combined in different ways to form an LED bulb or a portion thereof.

According to the utility model discloses an embodiment discloses a LED filament, the LED filament is located a plane rectangular coordinate system (X, Y), and wherein the X axle is on a parallel with the length direction of LED filament, the LED filament includes:

a plurality of LED chip units, any two adjacent of which are at different positions in a Y-axis direction;

and the two electrodes are configured corresponding to the LED chip units and are electrically connected with the LED chip units through leads.

Optionally, any two adjacent LED chip units are electrically connected to each other through a conductor, and an included angle between the conductor and the X-axis direction is 30 ° to 120 °.

Optionally, the conductor is a copper foil, a gold foil or a gold wire.

Optionally, any one of the plurality of LED chip units includes at least one LED chip.

Optionally, the length direction of the LED chip is parallel to the X-axis direction.

Optionally, the wire is parallel to, perpendicular to or at an angle with the X-axis direction.

Optionally, the number of the conducting wires is 2, and both the conducting wires are parallel to the X-axis direction.

Optionally, the LED filament further includes a light conversion layer covering the LED chip unit and the electrodes, and respectively exposing a portion of each of the two electrodes.

The application also discloses LED ball bubble lamp, it includes lamp holder, lamp body and the aforesaid LED filament, the lamp holder is connected the lamp body, the lamp body is made by the light-admitting quality material, the LED filament is located in the lamp body.

Optionally, the surface of the lamp housing is plated with a yellow film.

Due to the adoption of the technical scheme, at least one of the following beneficial effects or any combination thereof can be achieved: (1) the filament can be bent and lightened, the falling probability of the lead is reduced, and the reliability of the product is improved; (2) the LED filament structure is divided into the LED section and the conductor section, so that stress is easily concentrated on the conductor section when the LED filament is bent, and the probability of breakage of gold wires connected with adjacent chips in the LED section is reduced when the gold wires are bent, so that the overall quality of the LED filament is improved; in addition, the conductor section adopts a copper foil structure, so that the metal routing length is reduced, and the probability of metal routing fracture of the conductor section is further reduced; (3) the conductor or the lead connecting the LED chip unit and the conductor has an included angle with the length extending direction of the LED filament, so that the internal force on the sectional area of the conductor when the filament is bent can be effectively reduced, the probability of bending and breaking of the LED filament is reduced, and the overall quality of the LED filament is improved.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a segmented LED filament according to the present invention;

fig. 2A is a schematic structural diagram of another embodiment of a segmented LED filament according to the present invention;

fig. 2B to 2F are schematic structural diagrams of various embodiments of the segmented LED filament according to the present invention;

fig. 2G is a schematic perspective view of another embodiment of a segmented LED filament according to the present invention;

FIG. 2H shows a partial top view of FIG. 2G;

fig. 3 is a schematic cross-sectional view of various embodiments of the layered filament structure of the present invention;

fig. 4A to 4D are schematic cross-sectional views of different embodiments of the filament according to the present invention;

FIGS. 4E and 4F are schematic views of the chip placement added to FIGS. 4A and 4B;

fig. 5 is a schematic view of an interface through which light emitted from the LED chip of the present invention passes;

fig. 6A is a schematic cross-sectional view of the LED filament unit in the axial direction of the LED filament;

fig. 6B is a schematic cross-sectional view of the LED filament unit in the radial direction of the LED filament;

fig. 7A and 7B show cross-sectional views of LED filament units 400a1 of different top layer 420a shapes;

fig. 7C is a schematic cross-sectional view of various embodiments of the filament of the present invention;

fig. 8A to 8I are schematic top views of different embodiments of the present invention;

fig. 9A is a schematic structural diagram of an embodiment of the layered structure of the LED filament according to the present invention;

FIG. 9B is a schematic view of a bonding wire of an LED chip according to an embodiment;

FIG. 10 is a TMA analysis of polyimide before and after addition of a thermal curing agent;

FIG. 11 is a graph showing a distribution of sizes of heat dissipating particles of different specifications;

FIG. 12A is a SEM image of a composite film of the silicone-modified polyimide resin composition of the present invention;

FIGS. 12B and 12C are schematic cross-sectional views of composite films made of silicone-modified polyimide resin compositions according to embodiments of the present invention;

fig. 13A is a schematic view of an LED bulb using the LED filament of the present invention;

FIG. 13B is an enlarged cross-sectional view taken at the dashed circle in FIG. 13A;

fig. 13C shows a projection of the LED filament of the LED bulb lamp of fig. 13A in a top view; (ii) a

Fig. 14A is a schematic view of another LED bulb using the LED filament of the present invention;

FIG. 14B shows a front view of the LED bulb of FIG. 14A;

fig. 14C shows a top view of the LED bulb lamp of fig. 14A;

FIG. 14D is the LED filament of FIG. 14B as it would appear in a two-dimensional coordinate system defined by four quadrants;

fig. 14E shows the LED filament of fig. 14C in a two-dimensional coordinate system defined by four quadrants.

Detailed Description

The present disclosure provides a new LED filament and an LED bulb using the same, which will be described in the following embodiments with reference to the accompanying drawings. The following description of various embodiments of the invention presented herein is for the purpose of illustration and example only and is not intended to be exhaustive or limited to the precise forms disclosed. These example embodiments are merely examples, and many implementations and variations are possible that do not require the details provided herein. It should also be emphasized that this disclosure provides details of alternative examples, but that these alternative displays are not exclusive. Moreover, any agreement in detail between the various examples should be understood as requiring such detail as, after all, to be impractical for every possible variation of the feature set forth herein.

Terms such as "about" or "approximately" may reflect dimensions, orientations, or arrangements that vary only in a relatively minor manner and/or in a manner that does not significantly alter the operation, function, or structure of certain components. For example, a range from "about 0.1 to about 1" may encompass, for example, a range of 0% -5% deviation about 0.1 and 0% to 5% deviation about 1, particularly if such deviations maintain the same effect as the listed range.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The

LED chip units

102 and 104, or referred to as

LED segments

102 and 104, may be a single LED chip, or two LED chips, or may include a plurality of LED chips, i.e., equal to or greater than three LED chips.

Referring to fig. 1, fig. 1 is a schematic diagram of an embodiment of a segmented LED filament, and fig. 1 is a cross-sectional view of the LED filament along an axial direction thereof. As shown in fig. 1, the LED filament can be divided into different segments in the axial direction of the LED filament, for example, the LED filament can be divided into LED segments (i.e. LED chip units in the foregoing embodiments) 102 and 104 and a conductor segment 130, but not limited thereto. The number of the

LED segments

102, 104 and the conductor segments 130 in a single LED filament may be one or more, respectively, and the

LED segments

102, 104 and the conductor segments 130 are arranged along the axial direction of the LED filament. The

LED segments

102 and 104 and the conductor segment 130 may have different structural characteristics to achieve different effects.

As shown in fig. 1, the LED filament 100 includes

LED segments

102 and 104, a conductor segment 130, at least two

electrodes

110 and 112, and a light conversion layer 120, wherein the conductor segment 130 is located between two

adjacent LED segments

102 and 104, the

electrodes

110 and 112 are disposed corresponding to the

LED segments

102 and 104 and electrically connected to the

LED segments

102 and 104, the two

adjacent LED segments

102 and 104 are electrically connected to each other through the conductor segment 130, in this embodiment, the conductor segment 130 includes a conductor 130a connecting the

LED segments

102 and 104, a length of the conducting wire 140 is smaller than a length of the conductor 130a, or a shortest distance between two LED chips respectively located in the two

adjacent LED segments

102 and 104 is larger than a distance between two adjacent LED chips in the single LED segment 102/104. In addition, in other preferred embodiments of the present invention, each

LED segment

102, 104 includes at least two LED chips 142, the LED chips 142 are electrically connected to each other, and the electrical connection is performed through a wire 140; the present invention is not limited to this.

The light-converting layer 120 covers the

LED segments

102 and 104, the conductor segment 130, and the

electrodes

110 and 112, and exposes a portion of each of the two

electrodes

110 and 112. In this embodiment, each of the six faces of the LED chips 142 in the

LED segments

102, 104 is covered by the light conversion layer 120, that is, the six faces are covered by the light conversion layer 120 and can be referred to as the light conversion layer 120 enveloping the LED chips 142, and this covering or enveloping can be, but is not limited to, direct contact, and preferably, in this embodiment, each of the six faces of the LED chips 142 is in direct contact with the light conversion layer 120. In practice, however, the light conversion layer 120 may cover only two of the six surfaces of each LED chip 142. Likewise, the light conversion layer 120 may directly contact both surfaces of the two

electrodes

110, 112. In various embodiments, the light conversion layer 120 may be an encapsulant without light conversion function, for example, the light conversion layer 120 of the conductor segment 130 may be a transparent encapsulant with good flexibility.

In some embodiments, the LED filaments 100 are disposed in the LED bulbs, and each LED bulb has only a single LED filament to provide sufficient illumination. Moreover, in order to present aesthetic feeling in appearance, the illumination effect of a single LED filament can be more uniform and wide, and even the effect of full-circle light is achieved, so that the LED filament in the LED bulb lamp can present diversified curves through bending and flexing, the light emitting direction of the LED filament faces all directions through the diversified curves, or the overall light emitting shape of the LED bulb lamp is adjusted by the diversified curves. In order to make it easier for the LED filament to be bent into such a curved structure, and the LED filament can also bear the bending stress, the conductor section 130 of the LED filament does not have any LED chip therein, but only has the conductor 130 a. The conductor 130a (e.g. a metal wire or a metal coating) is easier to bend with respect to the LED chip, i.e. the conductor segment 130 without any LED chip will be correspondingly easier to bend with respect to the

LED segments

102, 104 with LED chips.

Referring to fig. 2A to fig. 2F, fig. 2A is a schematic structural diagram of another embodiment of the segmented LED filament according to the present invention. As shown in fig. 2A, the LED filament 400 has: a light conversion layer 420;

LED segments

402, 404; the

electrodes

410, 412; and a conductor segment 430 for electrically connecting between two

adjacent LED segments

402, 404. The LED segments 402,404 include at least two LED chips 442 electrically connected to each other by wires 440. In the present embodiment, the conductor segment 430 includes a conductor 430a connecting the

LED segments

402 and 404, wherein the shortest distance between two LED chips 442 respectively located in two

adjacent LED segments

402 and 404 is greater than the distance between two adjacent LED chips in the LED segment 402/404, and the length of the conducting wire 440 is less than the length of the conductor 430 a. Therefore, the conductor segments are prevented from being broken by the stress generated when the two LED segments are bent. The light conversion layer 420 is coated on at least two sides of the LED chip 442/

electrodes

410, 412. The light conversion layer 420 exposes a portion of the

electrodes

410, 412. The light conversion layer 420 may have at least a top layer 420a and a bottom layer 420b as the upper layer and the lower layer of the filament, respectively, in this embodiment, the top layer 420a and the bottom layer 420b are located on two sides of the LED chip 442/the

electrodes

410 and 412, respectively. It should be noted that, the thickness, diameter or width of the top layer 420a in the

LED segments

402 and 404 or the conductor segment 430 described in fig. 2A to 2H in the radial direction of the LED filament, or the thickness, diameter or width of the top layer of the

LED segments

402 and 404 or the conductor segment 430 in the radial direction of the LED filament refers to the distance from the top surface of the top layer 420a in the

LED segments

402 and 404 or the conductor segment 430 to the interface between the top layer 420a and the base layer 420b, or to the interface between the LED chip 442 or the conductor 430a and the base layer 420b, respectively, in the radial direction of the LED filament, and the top surface of the top layer 420a is a surface away from the base layer.

In this embodiment, the top layer 420a and the base layer 420b may have different particles or different particle densities according to different requirements. For example, in the case that the main light emitting surface of the LED chip 442 faces the top layer 420a, more light scattering particles can be added to the base layer 420b to improve the light distribution of the base layer 420b, so as to maximize the brightness generated by the base layer 420b, and even approach the brightness generated by the top layer 420 a. In addition, the base layer 420b may also have a higher density of phosphor to increase the hardness of the base layer 420 b. In the manufacturing process of the LED filament 400, the base layer 420b may be prepared first, and then the LED chip 442, the conductive wire 440 and the conductor 430a are disposed on the base layer 420 b. Since the base layer 420b has a hardness that can satisfy the requirements of the LED chip and the conductive wire to be disposed later, the LED chip 442, the conductive wire 440, and the conductor 430a can be disposed more stably without sagging or skewing. Finally, the top layer 420a covers the base layer 420b, the LED chip 442, the conductive wires 440 and the conductors 430 a.

As shown in fig. 2B, in the present embodiment, the conductor segment 430 is also located between two

adjacent LED segments

402 and 404, and the LED chips 442 in the

LED segments

402 and 404 are electrically connected to each other through the wires 440. However, the conductor 430a in the conductor segment 430 of fig. 2B is not in the form of a wire, but in the form of a sheet or film. In some embodiments, conductor 430a may be a copper foil, gold foil, or other material that is electrically conductive. In the present embodiment, the conductor 430a is attached to the surface of the base layer 420b and adjacent to the top layer 420a, i.e. between the base layer 420b and the top layer 420 a. The conductor segment 430 and the

LED segments

402 and 404 are electrically connected by a wire 450, that is, the two LED chips 442 located in the two

adjacent LED segments

402 and 404 and having the shortest distance from the conductor segment 430 are electrically connected to the conductor 430a in the conductor segment 430 by the wire 450. Wherein the length of the conductor segment 430 is greater than the distance between two adjacent LED chips in the

LED segments

402 and 404, and the length of the wire 440 is less than the length of the conductor 430 a. Such a design ensures good bendability of the conductor segment 430. Assuming that the maximum thickness of the LED chip in the radial direction of the filament is H, the thickness of the electrode and the conductor in the radial direction of the filament is 0.5H to 1.4H, preferably 0.5H to 0.7H. Therefore, the wire bonding process can be implemented, the quality of the wire bonding process (namely, good strength) is ensured, and the stability of the product is improved.

As shown in fig. 2C, in the present embodiment, the top layer 420a of the

LED segments

402 and 404 has the largest diameter (or the largest thickness) in the radial direction of the LED filament, the diameter of the top layer 420a gradually decreases from the

LED segments

402 and 404 to the conductor segment 430, and a part (e.g., the middle part) of the conductor 430a is not covered by the top layer 420 a. And the base layer 420b is uniform in width, thickness or diameter in the radial direction of the LED filament, whether in the LED segments 402,404 or in the conductor segment 430. In this embodiment, the number of LED chips 442 in each LED segment 402,404 may be different, for example, there is only one LED chip 442 in one LED segment 402,404, and there are two or more LED chips 442 in one

LED segment

402, 404. In addition to the number of LED chips 442, the

LED segments

402, 402 may have different types of LED chips 442.

As shown in fig. 2D, in this embodiment, the top layer 420a, whether in the LED segments 402,404 or the conductor segment 430, has a uniform width, thickness or diameter in the radial direction of the LED filament, and the base layer 420b may be recessed or hollowed out at the at least one conductor 430a, such that a portion (e.g., a middle portion) of the at least one conductor 430a is not covered by the base layer 420b, and the other at least one conductor 430a is completely covered by the base layer 420 b.

As shown in fig. 2E, in the present embodiment, the top layer 420a has a uniform width, thickness or diameter in the radial direction of the LED filament, whether in the

LED segments

402 and 404 or in the conductor segment 430, and the base layer 420b is recessed or hollowed out at all the conductors 430a, so that a portion (e.g., the middle portion) of each conductor 430a is not covered by the base layer 420 b.

As shown in fig. 2F, in the present embodiment, the top layer 420a of the

LED segments

402 and 404 has the largest diameter in the radial direction of the LED filament, the diameter of the top layer 420a gradually decreases from the

LED segments

402 and 404 to the conductor segment 430, and a part (e.g., the middle part) of the conductor 430a is not covered by the top layer 420 a. While base layer 420b is recessed or hollowed out at conductor 430a such that a portion (e.g., a middle portion) of conductor 430a is not covered by base layer 420 b. In other words, at least two opposite sides of the conductor 430a are not covered by the top layer 420a and the base layer 420b, respectively.

As described above with reference to the embodiments of fig. 2D-2F, when the base layer 420b has recesses or hollows in some or all of the conductor segments 430, the recesses or hollows may also be in the form of slits or slits, i.e., to provide good flexibility of the conductor segments 430 without exposing the conductors 430 a.

As shown in fig. 2G, in the present embodiment, the LED chip 442 has a length in the axial direction of the LED filament and a width in the X direction, and the ratio of the length to the width of the LED chip 442 is 2:1 to 6: 1. For example, in one embodiment, two LED chips are electrically connected as a chip unit, and the length-to-width ratio of the LED chip unit can be 6:1, so that the filament has a larger luminous flux. Moreover, the LED chip 442, the

electrodes

410 and 412 and the conductor 430a have thicknesses in the Y direction, the thicknesses of the

electrodes

410 and 412 are smaller than the thickness of the LED chip 442, the thickness Tc of the conductor 430a is also smaller than the thickness of the chip 442, that is, the conductor 430a and the

electrodes

410 and 412 are seemingly thinner than the chip 442. In addition, the top layer 420a and the base layer 420b have a thickness in the Y direction, and the thickness of the base layer 420b is smaller than the maximum thickness of the top layer 420 a. In the present embodiment, the conductor 430a appears parallelogram rather than rectangle in the top view along the Y direction, i.e. the included angle of the four sides of the conductor 430a appears in the top view is not 90 degree. In addition, two ends of the LED chip 442 are respectively connected to the

wires

440 or 450 to connect to another chip 442 or the conductor 430a through the

wires

440 or 450, and two ends of the LED chip 442 are used to connect to connection points of the

wires

440 or 450, which are not aligned with each other in the axial direction of the LED filament. For example, the connection point at one end of the chip 442 is shifted toward the negative X direction, and the connection point at the other end of the chip 442 is shifted toward the positive X direction, i.e., the two connection points at the two ends of the chip 442 are separated by a distance in the X direction.

As shown in fig. 2H, which is a partial top view of the conductor segment 430 of fig. 2G, it exhibits a wavy concave or convex structure 432a, and fig. 2G exhibits a bent form of the conductor segment 430 in the axial direction of the LED filament. In addition, in the present embodiment, the width of each concave structure 432a itself in the axial direction of the LED filament is irregular, that is, the width of any two positions of each concave structure 432a in the axial direction of the LED filament is unequal, for example, two positions of one concave structure 432a in fig. 2H have a width D1 and a width D2, respectively, and the width D1 is not equal to the width D2. In addition, in the present embodiment, the widths of the concave structures 432a in the axial direction of the LED filament are also irregular, for example, the widths of the concave structures 432a are not equal to each other where the concave structures are aligned in the axial direction of the LED filament, for example, two adjacent concave structures 432a in fig. 2H have a width D1 and a width D3 at two positions aligned in the axial direction, respectively, and the width D1 is not equal to the width D3. In other embodiments, the shape of the concave or convex structure 432a is a straight strip or a combination of a straight strip and a wave, and the shape of the concave or convex structure 432a of the top layer 420a at the conductor segment 430 can be a straight line or a combination of a straight line and a wave in a top view of the conductor segment.

In another embodiment, as shown in FIG. 3, the base layer 420b of the filament 400 is formed as a wavy surface having undulations thereon, and the LED segments 402,404 are disposed thereon in an undulating and tilted state. The filament has a wide light-emitting angle. That is, if the contact surface between the bottom surface of the base layer and the surface of the worktable is a horizontal plane, the LED segments are not necessarily arranged parallel to the horizontal plane, but arranged with a certain angle with the horizontal plane, and the arrangement height/angle/direction between each LED segment may also be different. In other words, if the center point of the LED segment is connected in series with a plurality of LED segments, the formed line may not be a straight line. Thus, the filament 400 can have the effect of increasing the light emitting angle and making the light emitting uniform even in the non-bent state.

According to the utility model discloses aforementioned each embodiment because LED filament structural differentiation is LED section and conductor segment, consequently the LED filament is easy with stress concentration in the conductor segment when buckling, makes the gold thread of connecting adjacent chip in the LED section reduce cracked probability when buckling, promotes the whole quality of LED filament by this. In addition, the conductor section adopts a copper foil structure, so that the length of the metal routing is reduced, and the probability of breaking the metal routing by bending is further reduced. Simultaneously in order to promote the nature of can buckling of LED filament conductor section, further avoid the conductor to produce when the LED filament is buckled and destroy the utility model discloses in other embodiments, the conductor in the LED filament conductor section can be "M" style of calligraphy or be wavy to the extension effect that provides the LED filament preferred.

The relevant design of the layered structure of the filament structure is explained next. Fig. 4A to 4C show examples of angle processing with respect to the surface of the filament, which are cross-sections of the filament. The top layer 420a in fig. 4A, 4B, and 4C is formed by a dispenser, and the two sides of the top layer naturally collapse to form an arc surface after dispensing by adjusting the viscosity of the phosphor paste. The cross section of the base layer 420b of fig. 4A is a quadrangular section formed by vertical cutting. The cross-section of the substrate 420B of fig. 4B is a trapezoidal section with oblique sides Sc formed by bevel cutting or cutting with an angled cutter. The base layer 420b of fig. 4C is similar to the base layer 420b of fig. 4A, but two corners located below the figure are surface-treated to form a circular arc angle Se. The filament can make the LED chip in the filament emit light through the various methods of the above-mentioned figures 4A to 4C, and the filament can integrally reach different light-emitting surface angles and light-emitting effects. The base layer 420B of fig. 4D is similar to the base layer 420B of fig. 4B, except that the sloping sides Sc of the base layer 420B in fig. 4D extend to the top layer 420a, and the cross-section of the top layer 420a is divided into a top arc portion and side sloping sides Sc. In other words, the top layer 420a and the bottom layer 420b of fig. 4D have a common bevel Sc, and the two bevel Sc are located on opposite sides of the LED filament. The hypotenuse Sc of the top layer 420a is aligned with the hypotenuse Sc of the base layer 420 b. In this case, the cross-section of the top layer 420a in FIG. 4D has an outer contour with two opposing oblique sides Sc and an arcuate edge. In the process flow of filament fabrication, the LED chip completes die bonding and wire bonding on the surface of the large-area base layer 420a, and after the top layer 420a is uniformly coated on the upper surface of the large-area base layer 420a, the filament strip is cut, so that the top layer 420a and the base layer 420b can have a common bevel edge Sc as shown in fig. 4D.

Fig. 4E is a schematic view of fig. 4A with the LED chips 442 arranged thereon, wherein the thickness and diameter of the base layer 420b can be smaller than those of the top layer 420 a. As shown in fig. 4E, the thickness T2 of the base layer 420b is smaller than the thickness T1 of the top layer 420a, the thickness of the base layer 420b or the top layer 420a is not uniform due to the manufacturing process, and T1 and T2 represent the maximum thickness of the top layer 420a and the base layer 420b, respectively; in addition, the LED chip 442 is disposed on the surface of the base layer 420b and wrapped in the top layer 420 a. In some aspects, the filament electrode (not shown) may be primarily disposed in the base layer 420 b. In the case where the base layer 420b is thinner than the top layer 420a, heat generated from the filament electrode can be more easily dissipated from the base layer 420 b. In some aspects, the LED chip 442 is disposed facing (mainly emitting light toward) the top layer 420a, so most of the light from the LED chip 442 penetrates the top layer 420a, which results in the base layer 420b having a lower brightness relative to the brightness of the top layer 420 a. The top layer 420a has a larger amount of light reflective/diffusive particles (e.g., phosphor) that can reflect or diffuse light toward the base layer 420b, and the light can easily penetrate the thinner base layer 420b, thereby making the brightness of the top layer 420a and the base layer 420b uniform. In another embodiment, when the top layer 420a and the base layer 420b have the same thickness, the phosphor concentration of the top layer 420a can be configured to be greater than that of the base layer 420b, so that the color temperature of the LED filament is more uniform.

As shown in fig. 4E and 4F, W1 is the width of the base layer 420b or the top layer 420a, and W2 is the width of the LED chip 442. When the widths of the base layer 420b or the top layer 420a are not uniform, W1 represents the width of the upper surface of the base layer 420b or the width of the lower surface of the top layer 420a, W1: w2 is 1: 0.8-0.9, the upper surface of the base layer 420b contacts the LED chip 402, and the lower surface of the base layer 420a is far away from the LED chip 442 and opposite to the upper surface of the base layer 420 b; the top surface of the top layer 420b is away from the LED chip 442, and the bottom surface of the top layer 420b is opposite to the top surface of the top layer 420b and contacts the base layer 420 a. W1 in fig. 4E indicates the width of the upper surface of the base layer 420b (or the minimum value of the width of the base layer 420 b); FIG. 4F is a schematic view of the LED chip 402 in FIG. 4B with W1 being the width of the bottom surface of top layer 420B (or the maximum width of top layer 420 a); in one embodiment, where the top layer 420a and the base layer 420b of FIG. 4D have a common bevel edge Sc, W1 is the width of the bottom surface of the top layer 420a (or the maximum width of the base layer 420 b). Since the LED chip 442 is a hexahedral light emitter on one hand, in order to ensure that the filament emits light laterally (i.e., the side of the LED chip 442 is still covered by the top layer 402 a), W1 and W2 may be designed to be unequal, and W1> W2; on the other hand, in order to ensure a certain flexibility of the filament and a small radius of curvature when the filament is bent (to ensure a certain flexibility of the filament), the ratio of the thickness and the width of the cross section of the filament perpendicular to the drawing length direction is preferably uniform. By adopting the design, the filament can easily realize the full-period lighting effect and has better bending property.

When the LED filament emits light in the LED bulb lamp packaged with inert gas, as shown in fig. 5, the light emitted by the LED chip 442 passes through interfaces a to F, where the interface a is an interface between GaN in the LED chip 442 and the top layer 420a, the interface B is an interface between the top layer 420a and the inert gas, the interface C is an interface between the substrate in the LED chip 442 and the solid crystal glue 450, the interface D is an interface between the solid crystal glue 450 and the base layer 420B, the interface E is an interface between the base layer 420B and the inert gas, and the interface F is an interface between the base layer 420B and the top layer 420 a. When light passes through the interfaces A-F, the refractive indexes of two substances at any interface are n1 and n2 respectively, and then | n1-n2| < 1.0, preferably | n1-n2| < 0.5, and more preferably | n1-n2| < 0.2. In one embodiment, B, E, D, F the refractive index of two substances at any one of the four interfaces is n1 and n2, respectively, such that | n1-n2| < 1.0, preferably | n1-n2| < 0.5, and more preferably | n1-n2| < 0.2. In one embodiment, the refractive index of the two substances at any one of the D, F interfaces is n1 and n2, respectively, such that | n1-n2| < 1.0, preferably | n1-n2| < 0.5, and more preferably | n1-n2| < 0.2. The smaller the absolute value of the difference in refractive index between the two substances at each interface, the higher the light extraction efficiency. For example, when light emitted by the LED chip 442 passes through the base layer 420b to the top layer 420a, the incident angle is θ 1, and the refraction angle is θ 2, assuming that the refractive index of the base layer 420b is n1 and the refractive index of the top layer 420a is n2, according to sin θ 1/sin θ 2 ═ n2/n1, the smaller the absolute value of the difference between n1 and n2, the closer the incident angle and the refraction angle are, the higher the light extraction efficiency of the LED filament is.

As shown in fig. 6A, an LED filament unit 400a1 including a single LED chip 442 is cut out of the LED filament 400 with the midpoint of two adjacent LED chips 442 as a boundary line, fig. 6A is a cross-sectional view of the LED filament unit 400a1 in the axial direction of the LED filament, and fig. 6B is a cross-sectional view of the LED filament unit 400a1 in the radial direction of the LED filament. As shown in fig. 6A and 6B, the light emitting angle of the LED chip 442 in the axial direction of the LED filament is α, the light emitting angle of the LED chip 442 in the radial direction of the LED filament is β, the surface of the LED chip 442 away from the base layer 420B is defined as the upper surface of the LED chip 442, the distance from the upper surface of the LED chip 442 to the outer surface of the top layer in the radial direction of the LED filament is H, the length of the LED filament unit 400a1 in the length direction of the LED filament is C, the light emitting area of one LED chip 442 in the LED filament in the axial direction of the LED filament is a central angle α, the top layer 420a has a sector area corresponding to the thickness H from the upper surface of the LED chip 442, and the linear distance parallel to the axial direction of the LED filament between two end points of the arc length in the sector area is set as; the light emitting area of one LED chip 442 in the LED filament in the radial direction of the LED filament is a central angle beta, the distance from the top layer 420a to the upper surface of the LED chip 442 is a sector area corresponding to the thickness H, and the linear distance between two end points of the arc length in the sector area, which is parallel to the radial direction of the LED filament, is set to be L2. Meanwhile, the LED filament has an ideal light emitting area, better bending property and heat dissipation performance, an obvious dark area of the LED filament is avoided, material waste is reduced, the value of L1 can be designed to be 0.5C-L1-10C, and preferably C-L1-2C. If the value of L1 is smaller than the value of C, the light emitting areas of the adjacent LED chips 442 in the axial direction cannot obtain an intersection, and the LED filament may have a dark area in the axial direction; when the L2 value is smaller than the W1 value, the LED chip 442 is too large in the radial/width direction of the LED filament, which may also cause the top layer 420a to generate dark areas on both sides of the radial/width direction. The appearance of dark space not only can influence the whole luminous efficiency of LED filament, indirectly causes the waste in the material use simultaneously. The specific values of α and β depend on the type or specification of the LED chip 442.

In one embodiment, in the axial direction of the LED filament:

h is L1/2tan0.5 alpha, L1 is more than or equal to 0.5C and less than or equal to 10C, and 0.5C/2tan0.5 alpha is more than or equal to H and less than or equal to 10C/2tan0.5 alpha;

in the radial direction of the LED:

h is equal to L2/2tan0.5 beta, L2 is equal to or more than W1, and H is equal to or more than W1/2tan0.5 beta;

thus, Hmax is 10C/2tan0.5 α, Hmin is a; a is set to the maximum value of 0.5C/2tan0.5 alpha and W1/2tan0.5 beta, and A is set to the maximum value of C/2tan0.5 alpha and W1/2tan0.5 beta.

Thus, a.ltoreq.H.ltoreq.10C/2 tan0.5 α, preferably A.ltoreq.H.ltoreq.2C/2 tan0.5 α. When the types of the LED chips 442, the distance between adjacent LED chips, and the width of the filament are known, the distance H from the light emitting surface of the LED chip 442 to the outer surface of the top layer can be determined, so that the filament can have an excellent light emitting area in both the radial direction and the axial direction of the filament.

The light emitting angles of most LED chips in the axial direction and the radial direction of the LED filament are 120 degrees, B is set to be the maximum value of 0.14C and 0.28W1, B is set to be the maximum value of 0.28C and 0.28W1, and then B is more than or equal to H and less than or equal to 2.9C; preferably B.ltoreq.H.ltoreq.0.58C.

In one embodiment, in the axial direction of the LED filament:

H＝L1/2tan0.5α，0.5C≤L1≤10C；

in the radial direction of the LED filament:

h is L2/2tan0.5 beta, L2 is more than or equal to W1; w1 is less than or equal to 2Htan0.5 beta;

then 0.5Ctan0.5 beta/tan 0.5 alpha is more than or equal to L2 is more than or equal to 10Ctan0.5 beta/tan 0.5 alpha, and L2 is more than or equal to W1;

therefore, W1 is less than or equal to 10Ctan0.5 beta/tan 0.5 alpha. Thus W1max ═ min (10Ctan 0.5. beta./tan 0.5. alpha., 2Htan 0.5. beta.)

The relation between the LED chip width W2 and the base layer width W1 has been set to W1: w2 is 1:0.8 to 0.9, and thus W1min is W2/0.9

When D is the minimum value of 10Ctan0.5 beta/tan 0.5 alpha and 2Htan0.5 beta and D is the minimum value of 2Ctan0.5 beta/tan 0.5 alpha and 2Htan0.5 beta, W2/0.9. ltoreq. W1. ltoreq.d, preferably W2/0.9. ltoreq. W1. ltoreq.D.

Knowing the type of the LED chip 442, the distance between two adjacent LED chips in the LED filament, and the H value, the range of the width W of the filament can be known, so that the filament can have a relatively excellent light emitting area in both the radial direction and the axial direction of the filament.

The light emitting angles of most LED chips in the axial direction and the radial direction of the LED filament are 120 degrees, E is set to be the minimum value of 10C and 3.46H, and E is the minimum value of 2C and 3.46H, so that 1.1W 2-W1-E, preferably 1.1W 2-W1-E.

In one embodiment, in the axial direction of the LED filament:

h is L1/2tan0.5 alpha, L1 is more than or equal to 0.5C and less than or equal to 10C, and then 0.2Htan0.5 alpha is more than or equal to C and less than or equal to 4Htan0.5 alpha;

in the radial direction of the LED filament:

h is L2/2tan0.5 beta, L2 is more than or equal to W1, and L1 is more than or equal to W1tan0.5 alpha/tan 0.5 beta;

therefore, W1tan0.5 alpha/tan 0.5 beta is less than or equal to 10C, so that C is more than or equal to 0.1W1tan0.5 alpha/tan 0.5 beta;

cmax is 4htan0.5 α;

setting F to be the maximum of 0.2Htan0.5 alpha and 0.1W1tan0.5 alpha/tan 0.5 beta, and F to be the maximum of Htan0.5 alpha and 0.1W1tan0.5 alpha/tan 0.5 beta, so that F is less than or equal to C less than or equal to 4Htan0.5 alpha, preferably F is less than or equal to C less than or equal to 2Htan0.5 alpha;

when the width and the height H of the LED filament and the type of the LED chip 442 are determined, the range of the width C of the filament can be known, so that the LED filament can have an excellent light emitting area in both the radial direction and the axial direction of the filament.

The light emitting angles of most LED chips in the axial direction and the radial direction of the LED filament are 120 degrees, G is set to be the maximum value of 0.34H and 0.1W1, G is set to be the maximum value of 1.73H and 0.1W1, and then G is less than or equal to C and less than or equal to 6.92H, preferably G is less than or equal to C and less than or equal to 3.46H.

In the above embodiment, the thickness of the LED chip 442 is small relative to the thickness of the top layer 420a, and therefore can be ignored in most cases, i.e., H can also represent the actual thickness of the top layer 420 a. In other embodiments, the light conversion layer is a structure similar to the light conversion layer 420 shown in FIG. 2A, for example, differing only in the position of the electrodes as shown in FIG. 2A, the height of the top layer 420a is suitable for the range of H.

Fig. 7A and 7B are cross-sectional views of LED filament units 400a1 of different top layer 420a shapes, with the surface of LED chip 442 away from base layer 420B and opposite the surface in contact with base layer 420B being denoted as Ca. In an embodiment, as shown in fig. 7A, the top layer 420a is shaped like a semicircle with different diameters, the center o of the top layer 420a does not overlap with the light emitting surface Ca of the LED chip 442, the distances between the two circumferences of the light emitted onto the outer surface of the top layer 420a are r1 and r2, respectively, when the light passes through the interface B (the interface between the top layer and the inert gas) in the same direction, the incident angles of the radii r1 and r2 of the top layer 420a are α and β, respectively, as can be known from tan α -m/r 1 and tan β -m/r 2, the larger the radius is, the smaller the incident angle is, and the higher the light emitting efficiency of the filament is; that is, when the top layer 420a has a semicircular cross-section, the maximum radius/diameter value should be as large as possible to obtain a better light extraction efficiency. In another embodiment, as shown in fig. 7B, the shape of one top layer 420a is a semicircle, the shape of the other top layer 420a is an ellipse, wherein the length of the major axis of the ellipse is the same as the diameter of the semicircle, and the center o of the top layer 420a and the center o of the ellipse do not overlap with the light emitting surface a of the LED chip. As can be seen from fig. 7B, when light passes through the B interface in the same direction, the distances from the circumference to the elliptical arc are r1 and r2, respectively, and the incident angles are α and β, respectively, as can be seen from tan α being m/r1 and tan β being m/r2, the larger r1 and r2 are, the smaller the incident angles are, and the higher the light extraction efficiency of the filament is; that is, compared to the oval shape, when the cross-section of the top layer 420a is designed to be a semicircular shape (i.e. the distance from the center point of the light-emitting Ca of the LED chip to the outer surface of the top layer is substantially the same), a better light-emitting efficiency can be obtained. As shown in fig. 7C, the center O of the top layer 420a indicated by the solid line does not overlap with the light-emitting surface a of the LED chip, the center O 'of the top layer 420a indicated by the dotted line overlaps with the light-emitting surface of the LED chip, and the radius of the semicircle with the center O being equal to the radius of the semicircle with the center O', as can be seen from the figure, tan α is m1/r, tan β is m2/r, and m1 is greater than m2, so α is greater than β, and when the light-emitting surface overlaps with the center (i.e., the distance from the center point of the light Ca emitted by the LED chip to the outer surface of the top layer is substantially the same), the light-emitting.

The LED chip can be replaced by a back-plated chip, the plated metal is silver or gold alloy, and when the back-plated chip is adopted, the mirror reflection can be improved, and the light emitting quantity of the light emitting surface A of the LED chip can be increased.

The chip wire bonding related design of the LED filament is described next. Fig. 8A is a top view of an embodiment of the LED filament 300 according to the present invention in an unbent state, wherein the LED filament 300 includes a plurality of

LED chip units

302, 304, a conductor 330a, and at least two

electrodes

310, 312. The

LED chip units

302 and 304 may be a single LED chip, or may include a plurality of LED chips, i.e., two or more LED chips.

The conductor 330a is located between two adjacent

LED chip units

302, 304, the

LED chip units

302, 304 are located at different positions in the Y direction, the

electrodes

310, 312 are configured corresponding to the

LED chip units

302, 304 and are electrically connected to the

LED chip units

302, 304 through the wire 340, the two adjacent

LED chip units

302, 304 are electrically connected to each other through the conductor 330a, and an included angle between the conductor 330a and the filament in the length direction (X direction) is 30 ° to 120 °, preferably 60 ° to 120 °. In the prior art, the direction of the conductor 330a is parallel to the X direction, the internal stress acting on the sectional area of the conductor is larger when the filament is bent at the conductor, and the conductor 330a is configured to form a certain included angle with the X direction, so that the internal stress acting on the sectional area of the conductor when the filament is bent can be effectively reduced. The wires 340 form a certain included angle with the X direction, are parallel to each other, are perpendicular to each other, or are combined at any angle, in this embodiment, the LED filament 300 includes two wires 340, one wire 340 is parallel to the X direction, and the included angle between the other wire 340 and the X direction is 30 ° to 120 °. The LED filament 300 emits light when its

electrodes

310, 312 are energized (voltage or current source).

Fig. 8B to 8D show the case where the conductor in fig. 8A is 90 ° to the X direction, that is, the conductor 330a is perpendicular to the X direction, which can reduce the internal stress on the cross-sectional area of the conductor when the filament is bent, in the embodiment shown in fig. 8B, the lead 340 is parallel to and perpendicular to the X direction, the LED filament 300 includes two leads 340, one lead 340 is parallel to the X direction, and the other lead 340 is perpendicular to the X direction.

As shown in fig. 8C, the difference from the embodiment shown in fig. 8B is that the lead 340 is perpendicular to the X direction, the bending performance between the

electrodes

310 and 312 and the

LED chip units

302 and 304 is improved, and the conductor 330a and the lead 340 are simultaneously arranged perpendicular to the X direction, so that the filament can be bent well at any position.

Fig. 8E is a top view of the LED filament 300 according to the next embodiment in the unbent state, which is different from the embodiment shown in fig. 8C in that, in the X direction, the LED chip unit 304 is located between two adjacent LED chip units 302, and the projection in the Y direction does not have an overlapping region with the LED chip unit 302, so that when the filament is bent at the conductor 330a, the chip is not damaged, thereby improving the stability of the product quality.

As shown in fig. 8F, the LED filament 300 includes a plurality of

LED chip units

302, 304, a conductor 330a, and at least two

electrodes

310, 312, the conductor 330a is located between two adjacent

LED chip units

302, 304, and the

LED chip units

302, 304 are located at substantially the same position in the Y direction, so that the overall width of the LED filament 300 is smaller, and further the heat dissipation path of the LED chip is shortened, and the heat dissipation effect is improved. The

electrodes

310 and 312 are disposed corresponding to the

LED chip units

302 and 304 and electrically connected to the

LED chip units

302 and 304 through the wires 340, the LED chip unit 302/304 is electrically connected to the conductor 330a through the wires 350, the conductor 330a is substantially Z-shaped, which can increase the mechanical strength of the conductor and the area where the LED chip is located and can prevent the wires connecting the LED chip and the conductor from being damaged when the LED filament 300 is bent, and the wires 340 are disposed parallel to the X direction.

As shown in fig. 8G, the LED filament 300 includes a plurality of

LED chip units

302, 304, a conductor 330a, and at least two

electrodes

310, 312, the

LED chip units

302, 304 are at the same position in the Y direction, the conductor 330a is parallel to the X direction, the conductor 330a includes a first conductor 3301a and a second conductor 3302a, which are respectively located at two sides of the LED chip unit 302/304, the first conductor 3301a is located between two adjacent LED chip units, and is electrically connected to the LED chip unit 302/304 through a wire 350. The lead 350 is perpendicular to the X direction, so that the internal stress on the cross section area of the lead when the LED filament 300 is bent is reduced, and the bending resistance of the lead is improved. The second conductor 3302a and the LED chip 142 are not electrically connected, and the second conductor 3302a extends to the wire 340 along the X direction, so that when the LED filament 300 is subjected to an external force, the stress buffering effect can be achieved, the LED chip is protected, the product stability is improved, and then the stress on the two sides of the LED chip is balanced. The

electrodes

310, 312 are disposed corresponding to the

LED chip units

302, 304 and electrically connected to the

LED chip units

302, 304 through wires 340.

As shown in fig. 8H, the difference from the embodiment shown in fig. 8G is that the first conductor 3301a and the second conductor 3302a extend to the wire 340 in the X direction, and the first conductor 3301a and the second conductor 3302a are connected to the LED chip unit 302 and the LED chip unit 304 by the wire 350. In other embodiments, for example, the first conductor 3301a connects the LED chip unit 302 and the LED chip unit 304 through the wire 350, and the second conductor 3302a may not be electrically connected to the LED chip unit 302/304. Through setting up the conductor in LED chip both sides for when LED filament 300 buckles, can play the effect that increases LED filament 300 intensity and can disperse the produced heat of some LED chips when luminous again.

Fig. 8I is the utility model discloses the plan view of the next embodiment of the unbent state of LED filament 300, in this embodiment,

LED chip unit

302, 304 are single LED chip, and the width direction of

LED chip unit

302, 304 is parallel with the X direction, and preferred

LED chip unit

302, 304 are in substantially the same position in the Y direction, so can make the whole width of LED filament 300 less, and then shorten the heat dissipation route of LED chip, improve the radiating effect. Two adjacent

LED chip units

302 and 304 are connected through a conductor 330a, the included angle between the conductor 330a and the X direction is 30-120 degrees, the internal stress on the sectional area of the lead when the LED filament 300 is bent is reduced, and the bending resistance of the lead is improved. In other embodiments, the long side of the LED chip unit may have a certain angle with the X direction, so that the overall width of the LED filament 300 can be further reduced.

Fig. 9A is a schematic view of an embodiment of the layered structure of the LED filament 400 according to the present invention, in which the LED filament 400 has: a light conversion layer 420;

LED chip units

402, 404; the

electrodes

410, 412; and a conductor segment 430 for electrically connecting the two adjacent

LED chip units

402, 404. The

LED chip units

402 and 404 include at least two LED chips 442, which are electrically connected to each other through a wire 440. In the present embodiment, the conductor segment 430 includes a conductor 430a, the conductor segment 430 is electrically connected to the

LED segments

402 and 404 through a conducting wire 450, wherein a shortest distance between two LED chips 442 respectively located in two adjacent

LED chip units

402 and 404 is greater than a distance between two adjacent LED chips in the LED chip unit 402/404, and a length of the conducting wire 440 is smaller than a length of the conductor 430 a. The light conversion layer 420 is coated on at least two sides of the LED chip 442/

electrodes

410, 412. The light conversion layer 420 exposes a portion of the

electrodes

410 and 412, respectively. When the chip is being bonded along the X direction, for example, the wires and the conductors are gold wires, as shown in fig. 9B, the quality of the bonding wires is mainly determined by A, B, C, D, E five points, where 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 gold wire 440, C is between two sections of the gold wire 440, D is the connection between the gold wire 440 and the two solder bars 4402, and E is between the two solder bars 4402 and the surface of the chip 442, because point B is the first bending point when the gold wire 440 goes through the wire arc, and the diameter of the gold wire 440 at point D is relatively thin, the gold wire 440 is easily broken at points B and D, and thus, for example, when implementing the structure shown in fig. 9A, the top layer 420a only needs to cover points B and D when the LED filament 300 is packaged, and a part of the gold wire is exposed outside the light conversion layer. If the surface of the LED chip 442 farthest from the base layer 420b is defined as the upper surface of the LED chip 442, the distance from the upper surface of the LED chip 442 to the surface of the top layer 420a is 100-200 μm.

The material content of the LED filament of the present invention with respect to the base layer will be described next. Materials suitable for manufacturing the flexible LED filament substrate or the light conversion layer must have characteristics such as excellent light transmittance, good heat resistance, excellent thermal conductivity, appropriate refractive index, excellent mechanical properties, and difficulty in warping. These properties can be satisfied by adjusting the kinds and content ratios of the main material, the modifier and the additive contained in the silicone-modified polyimide composition. The utility model provides a filament substrate or light conversion layer that composition including organosilicon modified polyimide formed, this composition except can satisfying above-mentioned characteristic, also can be by adjusting the kind and the content of the main material, modifier and additive in specific or partial composition whole filament substrate or light conversion layer's characteristic to satisfy special demand environment. The adjustment of each characteristic is as follows.

Blending mode of organic silicon modified polyimide

The utility model provides an organic silicon modified polyimide, which comprises a repeating unit represented by the following general formula (I):

in the general formula (I), Ar¹Is a 4-valent organic group. The organic group may have a benzene ring or an alicyclic hydrocarbon structure, and the alicyclic hydrocarbon structure may be a monocyclic alicyclic hydrocarbon structure or an alicyclic hydrocarbon structure having a bridged ring. The organic group may be a benzene ring structure or an alicyclic hydrocarbon structure containing an active hydrogen functional group, and the active hydrogen functional group may be any one or more of a hydroxyl group, an amino group, a carboxyl group, an amide group, or a thiol group.

Ar²Is a 2-valent organic group which may have, for example, a monocyclic alicyclic hydrocarbon structure, or a 2-valent organic group containing an active hydrogen functional group which is a hydroxyl, amino, carboxyl, amide or thiol groupAny one or more than one of them.

Each R is independently selected from methyl or phenyl.

n is 1-5, preferably n is 1 or 2 or 3 or 5.

The number average molecular weight of the general formula (I) is 5000 to 100000, preferably 10000 to 60000, and more preferably 20000 to 40000. The number average molecular weight is a polystyrene conversion value based on a calibration curve prepared by a Gel Permeation Chromatography (GPC) apparatus using standard polystyrene. When the number average molecular weight is 5000 or less, it is difficult to obtain good mechanical properties after curing, and particularly, the elongation tends to decrease. On the other hand, when it exceeds 100000, the viscosity becomes too high, making the resin difficult to form.

Ar¹Is a component derived from a dianhydride comprising an aromatic acid anhydride and an aliphatic acid anhydride, and the aromatic acid anhydride includes an aromatic acid anhydride containing only a benzene ring, a fluorinated aromatic acid anhydride, an amide group-containing aromatic acid anhydride, an ester group-containing aromatic acid anhydride, an ether group-containing aromatic acid anhydride, a sulfur group-containing aromatic acid anhydride, a sulfone group-containing aromatic acid anhydride, a carbonyl group-containing aromatic acid anhydride, and the like.

Examples of the aromatic acid anhydride containing only a benzene ring include pyromellitic anhydride (PMDA), 2,3,3',4' -biphenyltetracarboxylic dianhydride (bpda), 3,3',4,4' -biphenyltetracarboxylic dianhydride (sBPDA), 4- (2, 5-dioxotetrahydrofuran-3-yl) -1,2,3, 4-tetrahydronaphthalene-1, 2-dicarboxylic anhydride (TDA), and the like; fluorinated aromatic anhydrides such as 6FDA 4,4' - (hexafluoroisopropylene) diphthalic anhydride; aromatic acid anhydrides containing an amide group include N, N ' - (5,5' - (perfluoropropyl-2, 2-diyl) bis (2-hydroxy-5, 1-phenylene)) bis (1, 3-dioxo-1, 3-dihydroisobenzofuran) -5-carboxamide) (6FAP-ATA), N ' - (9H-fluoren-9-ylidene-di-4, 1-phenylene) bis [1, 3-dihydro-1, 3-dioxo-5-isobenzofurancarboxamide ] (FDA-ATA), and the like; the aromatic acid anhydride containing an ester group includes p-phenyl bis (trimellitate) dianhydride (TAHQ), etc.; the aromatic acid anhydride containing an ether group includes 4,4' - (4,4' -isopropyldiphenoxy) bis (phthalic anhydride) (BPADA), 4' -oxydiphthalic anhydride (sODPA), 2,3,3',4' -diphenylether tetracarboxylic dianhydride (aODPA), 4' - (4,4' -isopropyldiphenoxy) bis (phthalic anhydride) (BPADA), etc.; the sulfur-group-containing aromatic acid anhydride includes 4,4' -bis (phthalic anhydride) sulfide (TPDA), etc.; sulfone group-containing aromatic acid anhydrides include 3,3',4,4' -diphenylsulfone tetracarboxylic acid dianhydride (DSDA) and the like; the carbonyl group-containing aromatic acid anhydride includes 3,3',4,4' -benzophenonetetracarboxylic dianhydride (BTDA) and the like.

Alicyclic acid anhydrides include 1,2,4, 5-cyclohexane tetracarboxylic dianhydride abbreviated as HPMDA, 1,2,3, 4-Butanetetracarboxylic Dianhydride (BDA), tetrahydro-1H-5, 9-methanopyrano [3,4-d ] oxanone-1, 3,6,8(4H) -Tetraone (TCA), hexahydro-4, 8-ethylene-1H, 3H-benzo [1, 2-C: 4,5-C' ] difuran-1, 3,5, 7-tetraone (BODA), cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3, 4-cyclopentanetetracarboxylic dianhydride (CpDA), etc., or an alicyclic acid anhydride having an olefin structure such as bicyclo [2.2.2] oct-7-ene-2, 3,5, 6-tetracarboxylic dianhydride (COeDA). If an acid anhydride having an ethynyl group such as 4,4' - (acetylene-1, 2-diyl) diphthalic anhydride (EBPA) is used, the mechanical strength of the light conversion layer can be further ensured by post-curing.

From the viewpoint of solubility, 4,4 '-oxydiphthalic anhydride (sODPA), 3',4,4 '-benzophenonetetracarboxylic dianhydride (BTDA), cyclobutanetetracarboxylic dianhydride (CBDA), and 4,4' - (hexafluoroisopropylidene) diphthalic anhydride (6FDA) are preferable. The above dianhydrides can be used singly or in combination of two or more.

Ar²And a component derived from a diamine which can be classified into an aromatic diamine and an aliphatic diamine, and 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, and the like.

Aromatic diamines having only a benzene ring structure include m-phenylenediamine, p-phenylenediamine, 2, 4-diaminotoluene, 2, 6-diamino-3, 5-diethyltoluene, 4 '-diamino-3, 3' -dimethylbiphenyl, 9-bis (4-aminophenyl) Fluorene (FDA), 9-bis (4-amino-3-tolyl) fluorene, 2-bis (4-aminophenyl) propane, 2-bis (3-methyl-4-aminophenyl) propane, 4 '-diamino-2, 2' -dimethylbiphenyl (APB); fluorinated aromatic diamines including 2,2' -BIS (trifluoromethyl) diaminobiphenyl (TFMB), 2-BIS (4-aminophenyl) hexafluoropropane (6FDAM), 2-BIS [4- (4-aminophenoxy) phenyl ] Hexafluoropropane (HFBAPP), 2-BIS (3-amino-4-tolyl) hexafluoropropane and the like) (BIS-AF) and the like; the aromatic diamine containing an ester group includes [4- (4-aminobenzoyl) oxyphenyl ] -4-Aminobenzoate (ABHQ), di-p-aminophenyl terephthalate (BPTP), p-aminobenzoate (APAB), etc.; the aromatic diamine containing an ether group includes 2, 2-bis [4- (4-aminophenoxy) phenyl ] propane) (BAPP), 2 '-bis [4- (4-aminophenoxy phenyl) ] propane (ET-BDM), 2, 7-bis (4-aminophenoxy) -naphthalene (ET-2,7-Na), 1, 3-bis (3-aminophenoxy) benzene (TPE-M), 4' - [1, 4-phenylbis (oxy) ] bis [3- (trifluoromethyl) aniline ] (p-6FAPB), 3,4 '-diaminodiphenyl ether, 4' -diaminodiphenyl ether (ODA), 1, 3-bis (4-aminophenoxy) benzene (TPE-R), 1, 4-bis (4-aminophenoxy) benzene (TPE-Q), 4,4' -bis (4-aminophenoxy) biphenyl (BAPB), and the like; the aromatic diamine containing an amide group includes N, N ' -bis (4-aminophenyl) benzene-1, 4-dicarboxamide (BPTPA), 3,4' -diaminobenzanilide (m-APABA), 4' -Diaminobenzanilide (DABA), etc.; the aromatic diamine containing carbonyl group includes 4,4 '-diaminobenzophenone (4,4' -DABP), bis (4-amino-3-carboxyphenyl) methane (or referred to as 6,6 '-diamino-3, 3' -methylene dibenzoic acid), etc.; the hydroxyl group-containing aromatic diamine includes 3,3' -dihydroxybenzidine (HAB), 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (6FAP), etc.; the aromatic diamine containing carboxyl group includes 6,6 '-diamino-3, 3' -methylene dibenzoic acid (MBAA), 3, 5-diaminobenzoic acid (DBA), etc.; the sulfone group-containing aromatic diamine includes 3,3' -diaminodiphenyl sulfone (DDS), 4' -diaminodiphenyl sulfone, bis [4- (4-aminophenoxy) phenyl ] sulfone (BAPS) (otherwise known as 4,4' -bis (4-aminophenoxy) diphenyl sulfone), 3' -diamino-4, 4' -dihydroxydiphenyl sulfone (ABPS); the sulfur group-containing aromatic diamine includes 4,4' -diaminodiphenyl sulfide.

The aliphatic diamine is diamine without aromatic structure (such as benzene ring), the alicyclic diamine includes monocyclic alicyclic diamine, straight chain aliphatic diamine, the straight chain aliphatic diamine includes silicon oxygen type diamine, linear alkyl diamine, and linear aliphatic diamine containing ether group, the monocyclic alicyclic diamine includes 4,4' -diaminodicyclohexylmethane (PACM), 3-dimethyl-4, 4-diaminodicyclohexylmethane (DMDC); the silicone type diamine (also called amino modified silicone) includes alpha, omega- (3-aminopropyl) polysiloxane (KF8010), X22-161A, X22-161B, NH15D, 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane (PAME), etc.; the number of carbon atoms of the linear alkyl diamine is 6-12, and the linear alkyl diamine without a substituent is preferred; the ether group-containing linear aliphatic diamine includes ethylene glycol di (3-aminopropyl) ether and the like.

The diamine can also be selected from diamine containing fluorenyl, wherein fluorenyl has huge free volume and rigid condensed ring structure, and can ensure that polyimide has good heat resistance, thermal oxidation stability, mechanical property, optical transparency and good solubility in organic solvent, and the diamine containing fluorenyl, such as 9, 9-bis (3, 5-difluoro-4-aminophenyl) fluorene, which can be obtained by the reaction of 9-fluorenone and 2, 6-dichloroaniline. The fluorinated diamine can also be 1, 4-bis (3 '-amino-5' -trifluoromethylphenoxy) biphenyl, the diamine is meta-substituted fluorine-containing diamine with a rigid biphenyl structure, the meta-substituted structure can block charge flow along the molecular chain direction, and the intermolecular conjugation effect is reduced, so that the absorption of visible light to light is reduced, and the diamine or anhydride with an asymmetric structure can improve the transparency of the organic silicon modified polyimide resin composition to a certain extent. The above diamines may be used alone or in combination of two or more.

Examples of the diamine having an active hydrogen include diamines having a hydroxyl group such as 3,3 '-diamino-4, 4' -dihydroxybiphenyl, 4 '-diamino-3, 3' -dihydroxy-1, 1 '-biphenyl (or referred to as 3,3' -dihydroxybiphenylamine) (HAB), 2-bis (3-amino-4-hydroxyphenyl) propane (BAP), 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (6FAP), 1, 3-bis (3-hydroxy-4-aminophenoxy) benzene, 1, 4-bis (3-hydroxy-4-aminophenyl) benzene, 3 '-diamino-4, 4' -dihydroxydiphenyl sulfone (ABPS) can be exemplified, as the diamine having a carboxyl group, 3, 5-diaminobenzoic acid, bis (4-amino-3-carboxyphenyl) methane (otherwise known as 6,6 '-diamino-3, 3' -methylenedibenzoic acid), 3, 5-bis (4-aminophenoxy) benzoic acid, 1, 3-bis (4-amino-2-carboxyphenoxy) benzene are exemplified. Diamines having an amino group include, for example, 4' -Diaminobenzanilide (DABA), 2- (4-aminophenyl) -5-aminobenzimidazole, diethylenetriamine, 3,3' -diaminodipropylamine, triethylenetetramine, and N, N ' -bis (3-aminopropyl) ethylenediamine (or N, N-bis (3-aminopropyl) ethylethylamine). Diamines containing thiol groups, for example 3, 4-diaminobenzenethiol. The above diamines may be used alone or in combination of two or more.

The organic silicon modified polyimide can be synthesized by a known synthesis method. Dianhydrides and diamines can be prepared by dissolving them in an organic solvent for imidization in the presence of a catalyst, examples of which include acetic anhydride/triethylamine type, valerolactone/pyridine type, etc., preferably, water generated during azeotropic process in imidization reaction, and removal of water is facilitated by using a dehydrating agent such as toluene.

In other embodiments, a small portion of amic acid can be present in the main chain of the polyimide, for example, the ratio of amic acid to imide in the polyimide molecule is 1-3: 100, and there is an interaction force between amic acid and epoxy resin, so that the substrate has superior performance. In other embodiments, the substrate can also be obtained by adding solid materials (such as thermal curing agent, inorganic heat-dissipating particles and phosphor) in the state of polyamic acid. In addition, the alicyclic anhydride and the diamine can be directly heated and dehydrated to obtain the solubilized polyimide, and the solubilized polyimide is used as a glue material, has good light transmittance and is liquid, so that other solid substances (such as inorganic heat dissipation particles and fluorescent powder) can be more fully dispersed in the glue material.

In one embodiment, when preparing the silicone-modified polyimide, the diamine and the anhydride are heated and dehydrated to obtain polyimide, and the silicone-type diamine is dissolved in a solvent to obtain the silicone-modified polyimide. In another embodiment, the reaction is carried out with a silicone-type diamine in the state of amic acid (amic-acid) before the polyimide is obtained.

Further, an acid anhydride and a diamine may be used, and an imide compound obtained by dehydrating, ring-closing and polycondensing the acid anhydride and the diamine may be used, for example, an acid anhydride and a diamine having a molecular weight ratio of 1: 1. In one example 200 millimoles (mmol) of 4,4'- (hexafluoroisopropylidene) diphthalic anhydride (6FDA), 20 millimoles (mmol) of 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (6FAP), 50 millimoles (mmol) of 2,2' -bis (trifluoromethyl) diaminobiphenyl (TFMB), and 130 millimoles (mmol) of aminopropyl terminated poly (dimethylsiloxane) were used to obtain a PI synthesis solution.

Although the polyimide compound having an amino group as a terminal can be obtained by the above method, a polyimide compound having a carboxyl group as a terminal can be obtained by other methods. In addition, in the reaction of the acid anhydride and the diamine, when the main chain of the acid anhydride contains carbon-carbon triple bonds, the bonding force of the carbon-carbon triple bonds can strengthen the molecular structure; or a diamine containing a vinyl siloxane structure.

The molar ratio of dianhydride to diamine is 1: 1. Wherein the molar fraction of the diamine containing active hydrogen functional groups in the whole diamine is 5-25%. The reaction temperature for synthesizing the polyimide is preferably 80-250 ℃, more preferably 100-200 ℃, and the reaction time can be adjusted according to the size of the batch, for example, the reaction time for obtaining 10-30 g of polyimide is 6-10 hours.

The silicone-modified polyimide can be classified into two types, i.e., fluorinated aromatic silicone-modified polyimide and aliphatic silicone-modified polyimide. The fluorinated aromatic silicone-modified polyimide is synthesized from a silicone-type diamine, an aromatic diamine having a fluorine (F) group (or referred to as an F-substituted aromatic diamine), and an aromatic dianhydride having a fluorine (F) group (or referred to as an F-substituted aromatic anhydride); the aliphatic organosilicon modified polyimide is synthesized by dianhydride, silicon-oxygen type diamine and at least one diamine (also called aliphatic diamine) without aromatic structures (such as benzene rings), or the diamine (one diamine is silicon-oxygen type diamine) and at least one dianhydride (also called aliphatic anhydride) without aromatic structures (such as benzene rings), the aliphatic organosilicon modified polyimide comprises semi-aliphatic organosilicon modified polyimide and full-aliphatic organosilicon modified polyimide, and the full-aliphatic organosilicon modified polyimide is synthesized by at least one aliphatic dianhydride, silicon-oxygen type diamine and at least one aliphatic diamine; at least one aliphatic dianhydride or aliphatic diamine is used in the raw materials for synthesizing the semi-aliphatic organic silicon modified polyimide. The raw materials required for synthesizing the organic silicon modified polyimide and the silicon oxygen content of the organic silicon modified polyimide have certain influence on the transmittance, the color change performance, the mechanical performance, the warping degree and the refractive index of the base material.

The utility model discloses an organosilicon modified polyimide's siloxane content is 20 ~ 75 wt%, preferably 30 ~ 70 wt%, and glass transition temperature is below 150 ℃, and glass transition temperature (Tg)'s test condition is the glass transition temperature after adding the curing agent for TMA-60 survey of using the island jin preparation of Kabushiki Kaisha in organosilicon modified polyimide, test condition: loading: 5 g; temperature rise rate: 10 ℃/min; measuring the atmosphere: a nitrogen atmosphere; nitrogen flow rate: 20 ml/min; measurement temperature range: -40 to 300 ℃. When the siloxane content is less than 20%, a film made of the silicone-modified polyimide resin composition may become very hard and brittle due to the filling of the phosphor and the thermally conductive filler, and also warp after drying and curing, resulting in low processability; in addition, the resistance to thermal discoloration is reduced; when the siloxane content is more than 75%, the film made of the silicone-modified polyimide resin composition becomes cloudy, the light transmittance decreases, and the tensile strength of the film decreases. The utility model discloses the weight ratio of well siloxane content for silicon oxygen type diamine (the structural formula is shown as formula (A)) and organosilicon modified polyimide, the weight of organosilicon modified polyimide subtracts the weight of the water that produces in the synthetic process for the used diamine of synthetic organosilicon modified polyimide and dianhydride weight sum.

R in the formula (A) is selected from methyl or phenyl; r is preferably methyl, and n is 1-5, preferably 1,2,3, 5.

The organic solvent required for synthesizing the silicone-modified polyimide may be one that can dissolve the silicone-modified polyimide and ensure affinity (wettability) with the phosphor or filler to be added, but a large amount of the solvent is not left in the product, and the solvent is generally used in an amount of 1mol when the number of moles of the solvent is equal to the number of moles of water formed from the diamine and the acid anhydride, for example, 1mol of water formed from 1mol of the diamine and 1mol of the acid anhydride. In addition, the boiling point of the selected organic solvent at normal atmospheric pressure is 80 ℃ or higher and less than 300 ℃, more preferably 120 ℃ or higher and less than 250 ℃. Since drying and curing at a low temperature are required after coating, if the temperature is lower than 120 ℃, during the implementation of the coating process, it may not be well coated because the drying speed is too fast. If the boiling temperature of the organic solvent is selected to be higher than 250 deg.C, drying at a low temperature may be delayed. Specifically, the organic solvent is an ether organic solvent, an ester organic solvent, dimethyl ether, a ketone organic solvent, an alcohol organic solvent, an aromatic hydrocarbon solvent or the like. Ether organic solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether (or called ethylene glycol dibutyl ether), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether (or called diethylene glycol methyl ethyl ether), dipropylene glycol dimethyl ether or diethylene glycol dibutyl ether (diethylene glycol dibutyl ether), diethylene glycol butyl methyl ether; the ester organic solvent comprises acetic esters, the acetic esters comprise ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propyl acetate, propylene glycol diacetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, benzyl acetate or butyl carbitol acetate, and the ester solvent can also be methyl lactate, ethyl lactate, butyl ester, methyl benzoate or ethyl benzoate; dimethyl ether solvents include triglyme or tetraglyme; the ketone solvent includes acetylacetone, methyl propyl ketone, methyl butyl ketone, methyl isobutyl ketone, cyclopentanone, or 2-heptanone; the alcohol solvent comprises butanol, isobutanol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxybutanol or diacetone alcohol; the aromatic hydrocarbon solvent includes toluene or xylene; other solvents include gamma-butyrolactone, N-methylpyrrolidone, N-dimethylformamide, N-dimethylacetamide or dimethylsulfoxide.

The utility model provides an organic silicon modified polyimide resin composition, including above-mentioned organic silicon modified polyimide and thermosetting agent, the thermosetting agent is epoxy, isocyanate or two oxazoline compounds. In one embodiment, the amount of the thermal curing agent is 5 to 12% of the weight of the silicone modified polyimide based on the weight of the silicone modified polyimide. The organic silicon modified polyimide resin composition can further comprise heat dissipation particles and fluorescent powder.

Light transmittance

Factors affecting the light transmittance of the silicone-modified polyimide resin composition are at least the type of the main material, the type of the modifier (thermal curing agent), the type and content of the heat-dissipating particles, and the siloxane content. The light transmittance refers to the transmittance of light in the vicinity of the main light-emitting wavelength range of the LED chip, for example, in the vicinity of 450nm in the main light-emitting wavelength range of a blue LED chip, the absorbance of the composition or polyimide in the vicinity of 450nm is low enough or even not absorbed, so that most or all of the light can be ensured to pass through the composition or polyimide. In addition, when light emitted by the LED chip passes through the interface of the two substances, the closer the refractive indexes of the two substances are, the higher the light extraction efficiency is, the refractive index of the substance (such as the solid crystal glue) contacting with the filament substrate (or the base layer) is, so that the refractive index of the organic silicon modified polyimide composition is 1.4-1.7, preferably 1.4-1.55. The organic silicon modified polyimide resin composition is used for a filament substrate, and needs to have good light transmittance at the peak wavelength of InGaN of a blue excitation white LED. In order to obtain good transmittance, the raw materials for synthesizing the organic silicon modified polyimide, the thermal curing agent and the heat dissipation particles can be changed, and since the fluorescent powder in the organic silicon modified polyimide resin composition has a certain influence on the transmittance test, the organic silicon modified polyimide resin composition for measuring the transmittance does not contain the fluorescent powder, and the transmittance of the organic silicon modified polyimide resin composition is 86-93%, preferably 88-91%, or preferably 89-92%, or preferably 90-93%.

The acid anhydride and the diamine react to form the polyimide, wherein the acid anhydride and the diamine can be respectively selected from different compositions, namely, the polyimides formed by the reaction of different acid anhydrides and different diamines have different light transmittances. The aliphatic organic silicon modified polyimide resin composition comprises aliphatic organic silicon modified polyimide and a thermal curing agent, and the F-type aromatic organic silicon modified polyimide resin composition comprises F-type aromatic organic silicon modified polyimide and a thermal curing agent. The aliphatic silicone-modified polyimide resin composition has a high light transmittance because the aliphatic silicone-modified polyimide has an alicyclic structure. In addition, the fluorinated aromatic, semi-aliphatic and fully aliphatic polyimides have good light transmittance for blue LED chips. The fluorinated aromatic silicone-modified polyimide is synthesized from a silicone-type diamine, an aromatic diamine having a fluorine (F) group (or referred to as an F-substituted aromatic diamine), and an aromatic dianhydride having a fluorine (F) group (or referred to as an F-substituted aromatic anhydride), that is, Ar¹And Ar²Both of which have fluorine (F) groups. The semi-aliphatic and full-aliphatic organosilicon modified polyimide is synthesized by dianhydride, silicon-oxygen type diamine and at least one diamine (or called aliphatic diamine) without aromatic structures (such as benzene rings), or synthesized by diamine (one of which is silicon-oxygen type diamine) and at least one dianhydride (or called aliphatic anhydride) without aromatic structures (such as benzene rings), namely Ar¹And Ar²At least one of the two is an alicyclic hydrocarbon structure.

Although the main emission wavelength of the blue LED chip is 450nm, the blue LED chip may emit a small amount of light with a short wavelength of about 400nm due to the difference in the process conditions of the chip and the influence of the environment. The absorption rates of fluorinated aromatic, semi-aliphatic and fully aliphatic polyimides are different for light with a short wavelength of 400nm, and the absorption rate of the fluorinated aromatic polyimide for light with a short wavelength of about 400nm is about 20%, that is, the light transmittance of light with a wavelength of 400nm through the fluorinated aromatic polyimide is about 80%. The absorbance of the semi-aliphatic and fully aliphatic polyimides at a short wavelength of 400nm is lower than that of the fluorinated aromatic polyimides at a short wavelength of around 400nm, and the absorbance is only about 12%. Therefore, in one embodiment, if the LED chip used in the LED filament has a uniform quality and emits less blue light with a short wavelength, the fluorinated aromatic silicone modified polyimide can be used to fabricate the filament substrate or the light conversion layer. In another embodiment, if the LED chips used in the LED filament have different qualities and emit more blue light with short wavelength, the filament substrate or the light conversion layer can be made of semi-aliphatic or full-aliphatic silicone modified polyimide.

The addition of different thermal curing agents has different effects on the light transmittance of the organic silicon modified polyimide. Table 1-1 shows the effect of adding different thermal curing agents on the light transmittance of the all-aliphatic silicone modified polyimide, and under the condition that the main light-emitting wavelength of a blue LED chip is 450nm, the light transmittance of the all-aliphatic silicone modified polyimide is not significantly different by adding different thermal curing agents, but under the condition that the main light-emitting wavelength is 380nm, the light transmittance of the all-aliphatic silicone modified polyimide is affected by adding different thermal curing agents. The transmittance of the silicone-modified polyimide itself for light having a short wavelength (380nm) is inferior to that for light having a long wavelength (450nm), but the degree of difference varies depending on the addition of different thermosetting agents. For example, when the full-aliphatic silicone modified polyimide is added with the thermal curing agent KF105, the degree of decrease in light transmittance is small, but when the full-aliphatic silicone modified polyimide is added with the thermal curing agent 2021p, the degree of decrease in light transmittance may be large. Therefore, in one embodiment, if the LED chip used for the LED filament has a uniform quality and emits less blue light with a short wavelength, the thermal curing agent BPA or 2021p may be added. In contrast, in an embodiment, if the LED filament has different LED chip qualities and emits more blue light with short wavelength, the thermal curing agent KF105 may be optionally added. Tables 1-1 and 1-2 were each subjected to a light transmittance test using Shimadzu UV-1800. It has light transmittance at wavelengths of 380nm, 410nm and 450nm, respectively, according to the light emission of the white LED.

TABLE 1-1

Even if the same thermosetting agent is added, the light transmittance is affected differently when the amount of the thermosetting agent added is different. Tables 1-2 show that the light transmittance is improved when the addition amount of the heat-curing agent BPA of the all-aliphatic silicone-modified polyimide is increased from 4% to 8%. However, when the addition amount is further increased to 12%, the light transmittance is hardly exhibited. It was shown that the light transmittance became better as the amount of the heat-curing agent added increased, but when the amount was increased to a certain extent, the effect of adding more heat-curing agent on the light transmittance was considerably limited.

Tables 1 to 2

TABLE 2

Different heat-dissipating particles have different transmittances, and if the heat-dissipating particles with low transmittances or low light reflectivities are used, the light transmittance of the organic silicon modified polyimide resin composition is reduced. The utility model discloses a heat dissipation particle in organosilicon modified polyimide resin composition is preferred to adopt transparent powder, or the particle that the transmittance is high, or the particle that the light reflectivity is high, because the soft filament of LED mainly is used for giving out light, therefore the filament substrate need have good light transmissivity. In the case where two or more types of heat-dissipating particles are mixed, particles having high transmittance and particles having low transmittance are used in combination, and the proportion of the particles having high transmittance is made larger than that of the particles having low transmittance. For example, in one embodiment, the weight ratio of the particles with high transmittance to the particles with low transmittance is 3-5: 1.

Different siloxane contents also have an effect on light transmission. As can be seen from Table 2, the light transmission was only 85% at a siloxane content of only 37% by weight, but the light transmission was shown at a level of more than 94% as the siloxane content increased to more than 45%.

Heat resistance

Factors affecting the heat resistance of the silicone-modified polyimide resin composition are at least the type of main material, the silicone content, and the type and content of a modifier (thermal curing agent).

The organic silicon modified polyimide resin composition synthesized by organic silicon modified polyimide with fluorinated aromatic, semi-aliphatic and full aliphatic has excellent heat resistance, and is suitable for manufacturing filament substrates or light conversion layers. If carefully distinguished again, it was found that the fluorinated aromatic silicone-modified polyimide had better heat resistance properties than the aliphatic silicone-modified polyimide in the accelerated heat aging test (300 ℃ C.. times.1 hr). Therefore, in one embodiment, if the LED filament uses a high-power and high-brightness LED chip, the filament substrate or the light conversion layer can be made of fluorinated aromatic silicone modified polyimide.

The high or low siloxane content in the silicone-modified polyimide can affect the thermochromic resistance of the silicone-modified polyimide resin composition. The resistance to thermal discoloration means that the sample was left to stand at 200 ℃ for 24 hours, and the transmittance at a wavelength of 460nm of the sample after the standing was measured. As can be seen from Table 2, the transmittance after 200 ℃ C.. times.24 hours was only 83% when the siloxane content was only 37% by weight, the transmittance after 200 ℃ C.. times.24 hours was gradually increased as the siloxane content was increased, and the transmittance after 200 ℃ C.. times.24 hours was as high as 95% when the siloxane content was 73% by weight, so that increasing the siloxane content was effective in improving the thermal discoloration resistance of the silicone-modified polyimide.

The addition of the thermal curing agent can improve the heat resistance and the glass transition temperature. As shown in FIG. 10, A1 and A2 represent curves before and after the addition of the thermal curing agent, respectively; the curves D1 and D2 are obtained by differentiating the curves a1 and a2, respectively, and represent the degree of change of the curves a1 and a2, and from the analysis result of tma (thermal mechanical analysis) shown in fig. 10, the curve of thermal deformation is reduced when the thermal curing agent is added. Therefore, it is found that the addition of the thermosetting agent has an effect of improving the heat resistance.

When the organosilicon modified polyimide and the thermal curing agent are subjected to crosslinking reaction, the thermal curing agent only needs to have an organic group capable of reacting with an active hydrogen functional group in the polyimide, and the dosage and the type of the thermal curing agent have certain influence on the color change performance, the mechanical performance and the refractive index of the substrate, so that some thermal curing agents with better heat resistance and transmittance can be selected, and examples of the thermal curing agent comprise epoxy resin, isocyanate, bismaleimide or bisoxazoline compounds. The epoxy resin may be a bisphenol A type epoxy resin, such as BPA, and may also be a silicone type epoxy resin, such as KF105, X22-163, X22-163A, and may also be an alicyclic epoxy resin, such as 3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexylformate (2021P), EHPE3150 CE. Through the bridging reaction of the epoxy resin, a three-dimensional bridging structure is formed between the organic silicon modified polyimide and the epoxy resin, and the structural strength of the rubber material is improved. In one embodiment, the amount of the thermal curing agent used can also be determined according to the molar amount of the thermal curing agent reacting with the active hydrogen functional groups in the silicone modified polyimide. In one embodiment, the molar amount of active hydrogen functional groups reacted with the thermal curing agent is equal to the molar amount of the thermal curing agent, e.g., 1mol of active hydrogen functional groups reacted with the thermal curing agent, the molar amount of the thermal curing agent is 1 mol.

Thermal conductivity

Factors influencing the thermal conductivity of the organic silicon modified polyimide resin composition include at least the type and content of fluorescent powder, the type and content of heat dissipation particles and the addition and type of coupling agent. Among them, the particle size and particle size distribution of the heat dissipating particles also affect the thermal conductivity.

The organic silicon modified polyimide resin composition can also contain fluorescent powder for obtaining required luminescent characteristics, and the fluorescent powder can beThe wavelength of light emitted from the light emitting semiconductor is converted, for example, a yellow phosphor can convert blue light into yellow light, and a red phosphor can convert blue light into red light. Yellow phosphors, e.g. (Ba, Sr, Ca)₂SiO₄:Eu、(Sr,Ba)₂SiO₄Eu (barium orthosilicate (BOS)) and the like transparent phosphor, Y₃Al₅O₁₂Ce (yttrium aluminum garnet) and Tb₃Al₃O₁₂Silicate phosphors having a silicate structure such as Ce (yttrium aluminum garnet) and oxynitride phosphors such as Ca-. alpha. -SiAlON. The red phosphor comprises a nitride phosphor, such as CaAlSiN₃:Eu、CaSiN₂Eu. Green phosphors such as rare earth-halide phosphors, silicate phosphors, and the like. The content ratio of the phosphor in the silicone-modified polyimide resin composition can be arbitrarily set according to the desired light emission characteristics. In addition, since the thermal conductivity of the phosphor is much higher than that of the silicone-modified polyimide resin, the thermal conductivity of the entire silicone-modified polyimide resin composition is also improved as the content ratio of the phosphor in the silicone-modified polyimide resin composition is improved. Therefore, in one embodiment, on the premise of satisfying the light emitting characteristics, the content of the phosphor can be moderately increased to increase the thermal conductivity of the silicone modified polyimide resin composition, which is beneficial to the heat dissipation property of the filament substrate or the light conversion layer. When the silicone-modified polyimide resin composition is used as a filament substrate, the content, shape, and particle size of the phosphor in the silicone-modified polyimide resin composition also have a certain influence on the mechanical properties (e.g., elastic modulus, elongation, tensile strength) and the degree of warpage of the substrate. In order to make the base material have better mechanical property, thermal conductivity and small warping degree, the fluorescent powder contained in the organic silicon modified polyimide resin composition is granular, the shape of the fluorescent powder can be spherical, plate-shaped or needle-shaped, and the shape of the fluorescent powder is preferably spherical; the phosphor has a maximum average length (average particle diameter in a spherical shape) of 0.1 μm or more, preferably 1 μm or more, more preferably 1 to 100 μm, and still more preferably 1 to 50 μm; the dosage of the fluorescent powder is not less than 0.05 times of the weight of the organic silicon modified polyimidePreferably not less than 0.1 times, and not more than 8 times, and preferably not more than 7 times, for example, the weight of the silicone-modified polyimide is 100 parts by weight, the content of the phosphor is not less than 5 parts by weight, preferably not less than 10 parts by weight, and not more than 800 parts by weight, and preferably not more than 700 parts by weight, and when the content of the phosphor in the silicone-modified polyimide resin composition exceeds 800 parts by weight, the mechanical properties of the silicone-modified polyimide resin composition may not reach the strength required as a filament base layer, resulting in an increase in the fraction defective of products. In an embodiment, two phosphors are added simultaneously, for example, when red phosphor and green phosphor are added simultaneously, the ratio of red phosphor to green phosphor is 1: 5-8, and preferably 1: 6-7. In another embodiment, two phosphors are added simultaneously, for example, when red phosphor and yellow phosphor are added simultaneously, the ratio of red phosphor to yellow phosphor is 1: 5-8, preferably 1: 6-7. In other embodiments, three or more phosphors may be added simultaneously.

The purpose of adding the heat dissipation particles is mainly to increase the heat conductivity of the organic silicon modified polyimide resin composition, maintain the luminous color temperature of the LED chip and prolong the service life of the LED chip. Examples of the heat dissipating particles include silica, alumina, magnesia, magnesium carbonate, aluminum nitride, boron nitride, diamond, or the like. From the viewpoint of dispersibility, silica, alumina, or a combination of both thereof is preferably used. The heat dissipating particles may be spherical or block-like, and the spherical shape includes a shape similar to the spherical shape, and in one embodiment, spherical and non-spherical heat dissipating particles may be used to ensure the dispersibility of the heat dissipating particles and the thermal conductivity of the base material, and the weight ratio of the spherical to non-spherical heat dissipating particles is 1: 0.15-0.35.

Table 3-1 shows the relationship between the content of heat-dissipating particles and the thermal conductivity of the silicone-modified polyimide resin composition, and the thermal conductivity of the silicone-modified polyimide resin composition increases with the increase in the content of heat-dissipating particles, but when the content of heat-dissipating particles in the silicone-modified polyimide resin composition exceeds 1200 parts by weightThe mechanical properties of the silicone-modified polyimide resin composition may not achieve the strength required as a filament base layer, resulting in an increase in the product defective rate. In one embodiment, high-content and high-transmittance or high-reflectivity heat-dissipating particles (e.g., SiO) can be added₂、Al₂O₃) The light transmittance of the silicone-modified polyimide resin composition can be maintained, and the heat dissipation of the silicone-modified polyimide resin composition can be improved. Tables 3-1 and 3-2 show the thermal conductivity of the silicone-modified polyimide resin composition obtained as a test piece cut into a circle having a film thickness of 300um and a diameter of 30mm, measured by a thermal conductivity measuring device DRL-III manufactured by Hunan science, and the test conditions: hot plate temperature: 90 ℃; cold electrode temperature: 20 ℃; loading: 350N.

TABLE 3-1

The weight ratio is [ wt%]

0.0％

37.9％

59.8％

69.8％

77.6％

83.9％

89.0％

The volume ratio is [ vol%]

0.0％

15.0％

30.0％

40.0％

50.0％

60.0％

70.0％

Thermal conductivity [ W/m.K ]]

0.17

0.20

0.38

0.54

0.61

0.74

0.81

TABLE 3-2

For the influence of the particle size and distribution of the heat dissipating particles on the thermal conductivity of the silicone modified polyimide resin composition, please refer to table 3-2 and fig. 11. Tables 3-2 and fig. 11 show the results of adding 7 kinds of heat dissipating particles of different specifications in the same ratio to the silicone-modified polyimide resin composition and the influence on the thermal conductivity thereof. The particle size of the heat-dissipating particles suitable for addition to the silicone-modified polyimide resin composition can be roughly classified into a small particle size (less than 1 μm), a medium particle size (1 to 30 μm), and a large particle size (greater than 30 μm).

The first specification, the second specification and the third specification are compared, and the first specification, the second specification and the third specification are all only added with heat dissipation particles with medium particle size and are different from each other in average particle size. The results show that the average particle size of the heat-dissipating particles does not significantly affect the thermal conductivity of the silicone-modified polyimide resin composition when only the heat-dissipating particles having a medium particle size are added. Comparison of the specification (c) and (c) shows that the addition of the specification (c) having a small particle size and a medium particle size under the condition of similar average particle sizes exhibits a thermal conductivity significantly superior to the addition of the specification (c) having only a medium particle size. Comparison of the specifications (a) and (b) shows that, in the case where both the small particle size and the medium particle size are added, the average particle size of the heat-dissipating particles is different, but there is no significant influence on the thermal conductivity of the silicone-modified polyimide resin composition. Comparison of the specifications (c) and (c) shows that the specification (c) of adding a large-sized heat dissipating particle in addition to a small-sized heat dissipating particle and a medium-sized heat dissipating particle has the most excellent thermal conductivity. The specifications are compared with the specification of the fifth part and the seventh part, and although the heat dissipation particles with large, medium and small particle sizes are added in the specifications of the fifth part and the seventh part, the average particle size is similar, the thermal conductivity of the specification of the seventh part is obviously superior to that of the specification of the fifth part, and the reason for the difference is related to the proportion of particle size distribution. Referring to fig. 11, the size distribution of the specification (c) is shown in which the curve of the specification (c) is smooth and the slope is mostly very small, and shows that the specification (c) includes not only each particle size, but also each particle size content has a proper proportion, and the particle size distribution is in a normal distribution state, for example, the small particle size content is about 10%, the medium particle size content is about 60%, and the large particle size content is about 30%. Reversely viewing the specification, the curve of the specification has two areas with large slopes, the areas are respectively in the particle size of 1-2 μm and the particle size of 30-70 μm, which means that most of the particle size of the specification is distributed in the particle size of 1-2 μm and the particle size of 30-70 μm, only a small amount of heat dissipation particles with the particle size of 3-20 μm are contained, and the two areas are distributed.

Therefore, the degree of influence of the particle size distribution of the heat dissipating particles on the thermal conductivity is larger than the average particle size of the heat dissipating particles, and the silicone modified polyimide resin has the best thermal conductivity when the heat dissipating particles with three kinds of particle sizes, namely large, medium and small, are added, and the content of the small particle size is about 5-20%, the content of the medium particle size is about 50-70%, and the content of the large particle size is about 20-40%. Because the heat dissipation particles are densely packed and contacted to form an efficient heat dissipation path in the same volume under the condition of three kinds of particle sizes, namely large, medium and small particle sizes.

In one embodiment, for example, alumina with a particle size distribution of 0.1-100 μm and an average particle size of 12 μm or alumina with a particle size distribution of 0.1-20 μm and an average particle size of 4.1 μm is used, wherein the particle size distribution is within the particle size range of alumina. In another embodiment, the average particle size is 1/5 to 2/5, preferably 1/5 to 1/3, of the thickness of the substrate in view of the smoothness of the substrate. The amount of the heat dissipation particles is 1-12 times of the weight (amount) of the organosilicon modified polyimide, for example, 100 parts by weight of the organosilicon modified polyimide, 100-1200 parts by weight of the heat dissipation particles, preferably 400-900 parts by weight of the heat dissipation particles, two kinds of heat dissipation particles are simultaneously added, for example, silicon dioxide and aluminum oxide are simultaneously added, and the weight ratio of the aluminum oxide to the silicon dioxide is 0.4-25: 1, preferably 1-10: 1.

When the organic silicon modified polyimide resin composition is synthesized, the adhesion between solid substances (such as fluorescent powder and heat dissipation particles) and a glue material (such as organic silicon modified polyimide) can be improved by adding a coupling agent (such as a silane coupling agent), the dispersion uniformity of the whole solid substances can be improved, and further the heat dissipation performance and the mechanical strength of a light conversion layer can be improved. The amount of the coupling agent is related to the amount of the heat dissipating particles added and the specific surface area thereof, and the amount of the coupling agent is (the amount of the heat dissipating particles is the specific surface area of the heat dissipating particles)/the minimum coating area of the coupling agent, for example, an epoxy titanate coupling agent is used, and the amount of the coupling agent is (the amount of the heat dissipating particles is the specific surface area of the heat dissipating particles)/331.5.

In other embodiments of the present invention, in order to further improve the properties of the organic silicon modified polyimide resin composition in the synthesis process, additives such as a defoaming agent, a leveling agent or an adhesive may be optionally added during the synthesis process of the organic silicon modified polyimide resin composition, as long as the additives do not affect the optical rotation resistance, mechanical strength, heat resistance and discoloration of the product. The defoaming agent is used for eliminating bubbles generated at the time of printing, coating and curing, and for example, an acrylic or silicone based surfactant is used as the defoaming agent. The leveling agent is used to eliminate irregularities on the surface of the coating film generated during printing and coating. Specifically, the composition preferably contains 0.01 to 2 wt% of a surfactant component, can suppress bubbles, can smooth a coating film by using a leveling agent such as an acrylic or silicone type, and preferably contains no ionic impurities. Examples of the binder include imidazole compounds, thiazole compounds, triazole compounds, organoaluminum compounds, organotitanium compounds, and silane coupling agents. Preferably, these additives are used in an amount of not more than 10% by weight based on the silicone-modified polyimide. When the blending amount of the additive exceeds 10% by weight, the physical properties of the resulting coating film tend to be lowered, and there also arises a problem of deterioration in optical rotation resistance caused by volatile components.

Mechanical strength

The factors influencing the mechanical strength of the organic silicon modified polyimide resin composition are at least the type of main material, the content of siloxane, the type of modifier (thermal curing agent), the content of fluorescent powder and the content of heat dissipation particles.

Different silicone-modified polyimide resins possess different properties, and table 4 shows the main properties of three silicone-modified polyimides, fluorinated aromatic, semi-aliphatic and fully aliphatic, respectively, at a siloxane content of about 45% (wt%). Fluorinated aromatics possess the best resistance to thermal discoloration, while full-aliphatic have the best light transmittance. The fluorinated aromatics have both higher tensile strength and elastic modulus. The mechanical strength test conditions shown in tables 4 to 6 were: the silicone-modified polyimide resin composition had a thickness of 50 μm and a width of 10mm, and the tensile properties of the film were measured using ISO527-3:1995 standard at a tensile rate of 10 mm/min.

TABLE 4

When the filament is manufactured, the LED chip and the electrode are fixed on the filament substrate formed by the organic silicon modified polyimide resin composition through the die bond adhesive, then the routing procedure is carried out, and the adjacent LED chip, the LED chip and the electrode are electrically connected through the conducting wire. In order to ensure the quality of die bonding and wire bonding and improve the product quality, the elastic modulus of the filament substrate should have a certain level to resist the downward pressure of the die bonding and wire bonding processes, so the elastic modulus of the filament substrate should be greater than 2.0Gpa, preferably 2-6 Gpa, and most preferably 4-6 Gpa. Table 5 shows the effect of varying siloxane content and the presence or absence of particle (phosphor and alumina) addition on the elastic modulus of silicone modified polyimide resin compositions. Under the condition that fluorescent powder and alumina particles are not added, the elastic modulus of the organic silicon modified polyimide resin composition is less than 2.0Gpa, and the elastic modulus is reduced along with the increase of the siloxane content, namely the organic silicon modified polyimide resin composition is softened. However, the elastic modulus of the organosilicon modified polyimide resin composition can be greatly improved and is more than 2.0GPa under the condition of adding the fluorescent powder and the alumina particles. Therefore, the increase in the siloxane content can soften the silicone-modified polyimide resin composition, facilitating the addition of more fillers, such as more phosphors or heat-dissipating particles. In order to provide the base material with excellent elastic modulus and thermal conductivity, the particle size distribution and mixing ratio of the heat dissipating particles may be appropriately selected so that the average particle size is in the range of 0.1 μm to 100 μm, or in the range of 1 μm to 50 μm.

In order to make the LED filament have better bending performance, the elongation at break of the filament substrate should be greater than 0.5%, preferably 1 to 5%, and most preferably 1.5 to 5%. Referring to table 5, the silicone modified polyimide resin composition has excellent elongation at break without adding phosphor and alumina particles, and the elongation at break increases with increasing siloxane content, and the elastic modulus decreases with decreasing, thereby reducing the occurrence of warpage. On the contrary, in the case where the phosphor and the alumina particles are added, the silicone-modified polyimide resin composition exhibits a decrease in elongation at break, an increase in elastic modulus, and an increase in warpage.

TABLE 5

The addition of the thermal curing agent can improve the heat resistance and glass transition temperature of the organic silicon modified polyimide resin, and can also improve the mechanical properties of the organic silicon modified polyimide resin, such as tensile strength, elastic modulus and elongation at break. And different heat curing agents are added, so that different promotion effects can be achieved. Table 6 shows the effect of the silicone-modified polyimide resin composition showing different tensile strength and elongation at break after the addition of different heat curing agents. The full aliphatic organic silicon modified polyimide has better tensile strength after the thermal curing agent EHPE3150 is added, and has better elongation when the thermal curing agent KF105 is added.

TABLE 6

Table 7: specific information of BPA

Table 8: 2021P details of

Table 9: specific information of EHPE3150 and EHPE3150CE

Table 10: the refractive index can be called refractive index, and the specific information of PAME, KF8010, X22-161A, X22-161B, NH15D, X22-163, X22-163A and KF-105.

The organic silicon modified polyimide resin composition of the present invention can be used as a base material in a film form or attached to a carrier. The film formation process includes three steps, (a) a coating step: spreading the organic silicon modified polyimide resin composition on a stripping body, and coating to form a film; (b) a drying and heating procedure: heating and drying the film together with the peeling body to remove the solvent in the film; (c) stripping: after completion of the drying, the film was peeled from the peeled body to obtain a film-form silicone-modified polyimide resin composition. The peeling body may be a centrifugal film or other material that does not chemically react with the silicone-modified polyimide resin composition, and for example, a PET centrifugal film may be used.

The organic silicon modified polyimide resin composition is attached to a carrier to obtain a component film, the component film can be used as a base material, and the forming process of the component film comprises two procedures: (a) a coating process: spreading and coating the organic silicon modified polyimide resin composition on a carrier to form a composition film; (b) a drying and heating procedure: the constituent film is heat-dried to remove the solvent in the film.

As the coating method in the coating step, a roll-to-roll type coating apparatus such as a roll coater, a die coater, a knife coater, or the like, or a simple coating method such as a printing method, an ink jet method, a dispensing method, a spray method, or the like can be used.

The drying method corresponding to the above-mentioned heat drying step may be selected from a vacuum drying method, a heat drying method and the like. The heating method may be a heat radiation method in which heat is generated by heating a heat source such as an electric heater or a heat medium to generate indirect convection, or infrared rays emitted from the heat source are used for heating.

The above silicone-modified polyimide resin composition can be dried and cured after coating to obtain a high thermal conductive film (composite film) to obtain a film having the characteristics of any one or a combination of the following: excellent light transmission, chemical resistance, heat resistance, thermal conductivity, film mechanical properties and optical rotation resistance. The temperature and time used in the drying and curing process may be appropriately selected depending on the solvent in the silicone-modified polyimide resin composition and the film thickness to be coated, and whether or not the drying and curing are complete may be determined based on the change in weight of the silicone-modified polyimide resin composition before and after drying and curing and the change in peak value of the thermal curing agent functional group on an infrared spectrum, for example, when an epoxy resin is used as the thermal curing agent, the difference in weight of the silicone-modified polyimide resin composition before and after drying and curing is equal to the weight of the added solvent and the increase or decrease in peak value of the epoxy group before and after drying and curing is determined as whether or not the drying.

In one embodiment, the amidation reaction is performed in a nitrogen atmosphere, or a vacuum defoaming method or both methods are used during the synthesis of the organic silicon modified polyimide resin composition, so that the volume percentage of the cells in the organic silicon modified polyimide resin composition composite film is 5-20%, preferably 5-10%. As shown in fig. 12B, the silicone modified polyimide resin composition composite film was used as a substrate of an LED soft filament (as in the various LED filament examples described above), the substrate 420B had an upper surface 420B1 and an opposite lower surface 420B2, and fig. 12A shows the surface morphology of the substrate obtained by spraying gold on the surface of the substrate and observing it under a vega3 electron microscope of Tescan corporation. As can be seen from the SEM images of the substrate surface shown in fig. 12B and fig. 12A, there are cells 4d in the substrate, the volume percentage of the cells 4d in the substrate 420B is 5 to 20%, preferably 5 to 10%, the cross section of the cells 4d is irregular, as shown in fig. 12B, the cross section of the substrate 420B is shown schematically, the dotted line in fig. 12B is a reference line, the upper surface 420B1 of the substrate includes a first region 4a and a second region 4B, the second region 4B includes the cells 4d, the surface roughness of the first region 4a is smaller than that of the second region 4B, light emitted from the LED chip is scattered by the cells of the second region, and the light emission is more uniform; the lower surface 420b2 of substrate includes third region 4c, the surface roughness of third region 4c is greater than the surface roughness of first region 4a, when the LED chip was placed first region 4a, because first region 4a is more level and smooth, therefore be favorable to subsequent fixed routing, when the LED chip was placed in second region 4b, when third region 4c, the contact area of solid crystal glue and substrate was big during the solid crystal, can increase the bonding strength of solid crystal glue and substrate, therefore, place the LED chip on upper surface 420b1, can guarantee the solid crystal routing and the bonding strength of solid crystal glue and substrate simultaneously. When the organic silicon modified polyimide resin composition is used as the LED soft filament substrate, light emitted by an LED chip is scattered through bubbles in the substrate, the light is emitted more uniformly, and the glare phenomenon can be further improved. In one embodiment, the surface of the base layer 420b may be treated with a silicone resin or titanate coupling agent, preferably a silicone resin containing methanol or titanate coupling agent containing methanol, or a silicone resin containing isopropyl alcohol, and the treated base layer has a cross-sectional view as shown in fig. 12C, the upper surface 420b1 of the base layer has a relatively uniform surface roughness, the lower surface 420b2 of the base layer includes a third region 4C and a fourth region 4e, and the surface roughness of the third region 4C is greater than that of the fourth region 4 e. The surface roughness of the upper surface 420b1 of the base layer may be equal to the surface roughness of the fourth region 4 e. The surface of the base layer 420b is treated to allow a highly reactive and strong substance to enter a part of the pores 4d, thereby enhancing the strength of the base layer.

When the organosilicon modified polyimide resin composition is prepared by a vacuum defoaming method, the vacuum degree during vacuum defoaming is-0.5 to-0.09 MPa, preferably-0.2 to-0.09 MPa. When the total weight of the raw materials used for preparing the organic silicon modified polyimide resin composition is less than or equal to 250g, the revolution speed is 1200-2000 rpm, the rotation speed is 1200-2000 rpm, and the vacuum defoaming time is 3-8 min. Not only can keep certain bubbles in the film to increase the uniformity of light emission, but also can keep better mechanical property. The total weight of the raw materials required for preparing the silicone-modified polyimide resin composition can be appropriately adjusted, and generally, the higher the total weight is, the lower the vacuum degree can be, and the appropriate increase in the stirring time and the stirring speed can be achieved.

According to the utility model discloses, can obtain as the required luminousness of the soft filament substrate of LED, chemical resistance, heat-resisting discoloration, the thermal conductivity, the excellent resin of membrane mechanical properties and resistant optical rotation. Further, the highly thermally conductive resin film can be formed by a simple coating method such as a printing method coating method, an ink-jet method, a dispensing method, or the like.

When organosilicon modified polyimide resin composition complex film was as filament substrate (or basic unit), the LED chip was six luminous bodies, and during the preparation of LED filament, at least biplanar of LED chip was wrapped up by the top layer, and current LED filament when lighting, can appear the inhomogeneous phenomenon of top layer and basic unit colour temperature, or granular sensation can appear in the basic unit, therefore the complex film as the filament substrate need possess excellent transparency. In other embodiments, sulfone groups, non-coplanar structures, meta-substituted diamines, and the like may be introduced into the backbone of the silicone-modified polyimide to improve the transparency of the silicone-modified polyimide resin composition. In addition, in order to realize the full-period light emission effect of the bulb lamp adopting the filament, the composite film serving as a base material needs to have certain flexibility, so that flexible structures such as ether group (such as 4,4' -bis (4-amino-2-trifluoromethylphenoxy) diphenyl ether), carbonyl group, methylene group and the like can be introduced into the main chain of the organic silicon modified polyimide. In other embodiments, diamines or dianhydrides containing pyridine rings may also be selected, the rigid structure of the pyridine ring may enhance the mechanical properties of the composite film, and in combination with a strongly polar group (e.g., -F) may provide the composite film with excellent light transmission properties, and anhydrides having pyridine structures such as 2, 6-bis (3 ',4' -dicarboxyphenyl) -4- (3 ", 5" -bis trifluoromethylphenyl) pyridine dianhydride.

Referring to fig. 2A, the top layer 420a of the LED filament 400 is a layered structure with at least one layer. The layered structure may be selected from: fluorescent powder glue with high plasticity, fluorescent powder film with low plasticity, transparent layer or any layered combination of the three. The fluorescent powder glue/fluorescent powder film comprises the following components: glue, fluorescent powder and inorganic oxide nano particles. The glue may be, but is not limited to, silicone. In one embodiment, the glue may include 10 Wt% or less of the above-mentioned silicone modified polyimide to increase the hardness, insulation, thermal stability and mechanical strength of the filament as a whole, the solid content of the silicone modified polyimide may be 5-40 Wt%, and the rotational viscosity may be 5-20 pa.s. The inorganic oxide nanoparticles 426 may be, but not limited to, alumina or aluminum nitride particles, and the particle size of the particles may be 100-600 nm or 0.1-100 μm, which is used to promote heat dissipation of the filament, and the incorporated inorganic heat dissipation particles may have various sizes. The hardness (e.g., adjusted by the composition of the encapsulant or the ratio of the phosphors), the conversion wavelength, the particle size of the composition, the thickness, and the transmittance of the two materials can be adjusted to be different according to the situation. The transmittance of the phosphor film and the phosphor glue on the top layer can be adjusted according to the requirement, for example, the transmittance of the phosphor glue or the phosphor film on the top layer is more than 20%, 50%, or 70%. The Shore hardness of the fluorescent powder adhesive can be D40-70; the thickness of the fluorescent powder glue can be 0.2-1.5 mm; and the Shore hardness of the phosphor film can be D20-70. The thickness of the fluorescent powder film can be 0.1-0.5 mm; a refractive index of 1.4 or higher; the light transmittance is 40-95%. The transparent layer (glue layer, insulating layer) may be composed of a highly light-transmitting resin such as silica gel, the above-described silicone-modified polyimide, or a combination thereof. In one embodiment, the transparent layer can be used as an index matching layer for adjusting the light extraction efficiency of the filament.

With continued reference to fig. 2A, the base layer 420b of the LED filament 400 is at least one layer of a layered structure selected from: fluorescent powder glue with high plasticity, fluorescent powder film with low plasticity, transparent layer or any layered combination of the three; the fluorescent powder glue/fluorescent powder film comprises the following components: organic silicon modified polyimide, fluorescent powder and inorganic oxide nano particles. In one embodiment, the silicone-modified polyimide may be replaced with the silicone-modified polyimide resin composition described above. The inorganic oxide nanoparticles can be, but not limited to, alumina and aluminum nitride particles, the particle size of the particles can be 100-600 nm or 0.1-100 μm, which is used to promote the heat dissipation of the filament, and the incorporated inorganic heat dissipation particles can have various sizes. The light transmittance of the phosphor film and the phosphor paste in the base layer 420b can be adjusted as required, for example, the transmittance of the phosphor paste or the phosphor film in the base layer 420b is greater than 20%, 50%, or 70%. The transparent layer (glue layer, insulating layer) may be composed of a highly light-transmitting resin such as silica gel, the above-described silicone-modified polyimide, or a combination thereof. In one embodiment, the transparent layer can be used as an index matching layer for adjusting the light extraction efficiency of the filament. In one embodiment, the base layer 420b may be the organic silicon modified polyimide resin composition composite film described above.

The description of the application of the silicone modified polyimide to the filament structure is only represented by fig. 2A, but not limited thereto. The same remarks apply to all similar LED filament configurations of the present invention.

The LED filament structure in each embodiment can be mainly applied to LED bulb lamp products, so that the LED bulb lamp can achieve the light emitting effect of full-period light through the flexible bending characteristic of the single LED filament. The following further describes a specific embodiment of applying the aforementioned LED filament to an LED bulb lamp.

Referring to fig. 13A, fig. 13A is a schematic structural diagram of a first embodiment of an LED bulb 20 c. According to the first embodiment, the LED bulb 20c includes a lamp housing 12, a base 16 connected to the lamp housing 12, at least two

conductive brackets

51a and 51b disposed in the lamp housing 12, a driving circuit 518, a supporting portion (including the cantilever 15 and the stem 19), and a single light emitting portion (i.e., an LED filament) 100. The driving circuit 518 is electrically connected to the

conductive brackets

51a and 51b and the lamp head 16. The stem 19 further has a vertical rod 19a extending vertically to the center of the lamp housing 12, the vertical rod 19a is located on the central axis of the lamp head 16, or the vertical rod 19a is located on the central axis of the LED bulb 20 c. A plurality of cantilevers 15 are located between the rod 19a and the LED filament 100, and the cantilevers 15 are used to support the LED filament 100 and can maintain the LED filament 100 in a predetermined curve and shape. Each cantilever 15 includes opposite first and second ends, 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.

The lamp envelope 12 may be made of a material with better light transmission or better thermal conductivity, such as, but not limited to, glass or plastic. In practice, the lamp housing 12 may be doped with a golden yellow material or the surface of the lamp housing may be plated with a yellow film to absorb a portion of the blue light emitted from the LED chip, so as to reduce the color temperature of the light emitted from the LED bulb 20 c.

The electrodes 506 of the LED filament 100 are electrically connected to the

conductive legs

51a, 51b to receive power from the driving circuit 518. The connection between the electrode 506 and the

conductive supports

51a and 51b may be a mechanical press connection or a welding connection, and the mechanical connection may be formed by passing the conductive supports 51a and 51b through a specific through hole (not shown) formed on the electrode 506 and then bending the free ends of the

conductive supports

51a and 51b to clamp the electrode 506 and form an electrical connection between the

conductive supports

51a and 51 b. The solder connection may be by way of silver-based solder, silver solder, or the like, connecting

conductive brackets

51a, 51b to electrode 506.

The LED filament 100 shown in fig. 13A is bent to form a circular-like profile in the top view of fig. 13A. In the embodiment of fig. 13A, the LED filament 100 may be bent to form a wave shape in a side view since it has a structure including the LED filament as described in any one of the embodiments of fig. 1 to 9. The shape of the LED filament 100 is novel and makes the illumination more uniform. Compared to an LED bulb with multiple LED filaments, a single LED filament 100 has fewer contacts. In practice, a single filament 100 has only two connection points, thus reducing the possibility of defects due to welding or mechanical crimping.

The stem 19 has a stem 19a, the stem 19a extending toward the center of the envelope 12. The legs 19a support the cantilevers 15, a first end of each cantilever 15 is connected to the leg 19a, and a second end of each cantilever 15 is connected to the LED filament 100.

Referring to fig. 13B, fig. 13B is an enlarged cross-sectional view of the dotted circle of fig. 13A. The second end of each cantilever 15 has a clamp 15a, and the clamp 15a clamps the body of the LED filament 10. The clamp portion 15a may be used to clamp the wavy peaks or valleys of the LED filament 100, but not limited thereto, and the clamp portion 15a may also be used to clamp the portions between the wavy peaks and valleys of the LED filament 100. The shape of the pincer 15a may closely fit the outer shape of the cross section of the LED filament 100, and the size of the inner shape (inner hole) of the pincer 15a may be slightly smaller than the outer shape of the cross section of the LED filament 100. Thus, during manufacture, the LED filament 100 may be inserted through the inner bore of the clamp 15a to form a tight fit. The other fixing method is to form the pincer portion through a bending procedure, and further, the LED filament 100 is first placed at the second end of the cantilever 15, and then the second end is bent into the pincer portion 15a by a jig to clamp the LED filament 100.

The cantilever 15 may be made of, but not limited to, carbon spring steel to provide suitable rigidity and elasticity, so as to absorb external vibration and reduce impact on the LED filament, thereby making the LED filament less prone to deformation. Because the upright rod 19a extends to the center of the lamp housing 12, and the cantilever 15 is connected to the vicinity of the top end of the upright rod 19a, the vertical height of the LED filament 100 is close to the center of the lamp housing 12, so the light-emitting characteristic of the LED bulb 20c is close to the light-emitting characteristic of the conventional bulb, the light emission is more uniform, and meanwhile, the light-emitting brightness can also reach the brightness level of the conventional bulb. In the present embodiment, at least half of the LED filament 100 surrounds the central axis of the LED bulb 20 c. This central axis is coaxial with the axis of the upright 19 a.

In this embodiment, the first end of the cantilever 15 of the LED filament 100 is connected to the vertical rod 19a of the stem 19, and the second end of the cantilever 15 is connected to the outer insulating surface of the LED filament 100 through the clamp 15a, so the cantilever 15 is not used for transmitting power. In one embodiment, the stem 19 is made of glass, so that the stem 19 is not damaged or burst due to thermal expansion and contraction of the suspension wall 15. In various embodiments, the LED bulb may not have a stem, and the cantilever 15 may be connected to the stem or may be directly connected to the housing to reduce the negative impact on the light emission caused by the stem.

Because the cantilever 15 is non-conductive, the risk that the glass core column 19 is damaged and burst due to expansion and contraction of the metal wire in the cantilever 15 caused by heat generation of the passing current when the cantilever 15 is conductive in the past is avoided.

In various embodiments, the second end of the cantilever 15 may be directly inserted into the LED filament 100 and become an auxiliary (auxiliary bar) in the LED filament 100, which may strengthen the mechanical strength of the LED filament 100.

The inner shape (hole shape) of the pincer 15a matches the outer shape of the cross section of the LED filament 100, and therefore, the cross section of the LED filament 100 can be oriented toward a specific orientation. The top layer 420a of the LED filament 100 is oriented in the ten o' clock direction of fig. 2B, and the entire light emitting face of the LED filament 100 can be oriented in substantially the same orientation to ensure that the light emitting face of the LED filament 100 is visually uniform. The LED filament 100 includes a primary light emitting surface Lm and a secondary light emitting surface Ls corresponding to the LED chip. When the LED chips of the LED filament 100 are wire-bonded and aligned in a linear manner, the surface of the top layer 420a away from the base layer 420b is a primary light emitting surface Lm, and the surface of the base layer 420b away from the top layer 420a is a secondary light emitting surface Ls. The primary light emitting surface Lm and the secondary light emitting surface Ls oppose each other. When the LED filament 100 emits light, the primary light emitting surface Lm is a surface through which the maximum amount of light passes, and the secondary light emitting surface Ls is a surface through which the second maximum amount of light passes. In the present embodiment, a conductive foil 530 is further disposed between the top layer 420a and the base layer 420b for electrically connecting the LED chips. In the present embodiment, the LED filament 100 is wound with a coil so that the main light emitting surface Lm always faces outward. That is, any part of the primary light emitting surface Lm is directed towards the envelope 12 or burner 16 and at any angle away from the stem 19. The secondary light emitting surface Ls is always directed toward the stem 19 or toward the tip of the stem 19 (the secondary light emitting surface Ls is always directed inward).

The LED filament 100 shown in fig. 13A is bent to form a circle in a top view and a wave in a side view. The wave-shaped structure not only has novel appearance, but also can ensure uniform illumination of the LED filament 100. Meanwhile, compared to multiple LED filaments, the single LED filament 100 requires fewer contacts (e.g., press contacts, welding contacts, or soldering contacts) to connect the

conductive supports

51a and 51 b. In practice, a single LED filament 100 requires only two contacts, which are formed on two electrodes, respectively. Therefore, the risk of welding errors can be effectively reduced, and compared with mechanical connection in a pressing mode, the connection process can be simplified.

Referring to fig. 13C, fig. 13C is a projection of the LED filament 100 of the LED bulb 20C of fig. 13A in a top view. In one embodiment, as shown in fig. 13C, the LED filament may be bent to form a wave shape, and when viewed from the top, the wave shape may resemble a circle, and the circle may surround the center of the bulb or stem. In various embodiments, the LED filament viewed from a top view may form a circular-like or "U" -like shape.

As shown in fig. 13C, the LED filament 100 surrounds in a circular-like wave shape and has a symmetrical-like structure in a top view, and the light emitting surface of the LED filament 100 is also symmetrical. For example, in a top view, the main light emitting surface Lm may face outwardly. Due to the symmetrical characteristic, the LED filament 100 can produce a full-cycle effect. The symmetry property is about the quasi-symmetric structure of the LED filament 100 and the configuration of the light emitting surface of the LED filament 100 in a top view. Therefore, the whole LED bulb 20c can generate a full-cycle light effect similar to 360-degree light emission. In addition, the two contacts can be close to each other, so that the

conductive legs

51a, 51b are substantially lower than the LED filament 100. Visually, the

conductive legs

51a, 51b would appear less distinct and integrated with the LED filament 100 to exhibit a graceful curve.

Referring to fig. 14A and 14B, fig. 14A is a schematic view of an LED bulb lamp according to an embodiment of the present invention, and fig. 14B is a front view (or a side view) of the LED bulb lamp of fig. 14A. The LED bulb 20d of fig. 14A and 14B is similar to the LED bulb 20c of fig. 13A, and as shown in fig. 14A and 14B, the LED bulb 20d includes a lamp housing 12, a base 16 connected to the lamp housing 12, at least two conductive brackets 51a and 51B disposed in the lamp housing 12, a cantilever 15, a stem 19, and a single LED filament 100. The stem 19 includes a stem bottom and a stem top, which are opposite to each other, the stem bottom is connected to the lamp head 16, and the stem top extends into the lamp housing 12 along an extending direction of the stem 19, for example, the stem top may be located at the center of the lamp housing 12. In this embodiment the stem 19 comprises a pole 19a, where the pole 19a is considered as an integral part of the stem 19, and thus the top end of the stem 19 is the top end of the pole 19 a.

Conductive brackets

51a, 51b connect the stems 19. The LED filament 100 includes a filament body and two electrodes 506, the two electrodes 506 are located at two opposite ends of the filament body, and the filament body is the other part of the LED filament 100 not including the electrodes 506. The two filament electrodes 506 are respectively connected with two

conductive supports

51a and 51b, and the filament body surrounds the stem 19. One end of the cantilever 15 is connected to the stem 19 and the other end is connected to the filament body.

Referring to fig. 14C, fig. 14C is a top view of the LED bulb 20d of fig. 14A. As shown in fig. 14C, the LED filament 100 body includes a primary light emitting surface Lm and a secondary light emitting surface Ls. Any section of the primary light emitting surface Lm faces the bulb 12 or the base 16 at any angle, i.e., faces the outside of the LED bulb 20d or faces the outside of the bulb 12, and any section of the secondary light emitting surface Ls faces the stem 19 or the top of the stem 19 at any angle, i.e., faces the inside of the LED bulb 20d or faces the center of the bulb 12. In other words, when a user views the LED bulb 20d from the outside, the main light emitting surface Lm of the LED filament 100 is seen at any angle. Based on this arrangement, the effect of illumination will be better.

According to different embodiments, the LED filaments 100 in different LED bulbs (e.g., the

LED bulbs

0a, 20b, 20c, or 20d) may form different shapes or curves, and any of the LED filaments 100 may be configured to have symmetrical characteristics. The symmetrical characteristic is beneficial to generating uniform and widely distributed light rays, so that the LED bulb lamp can generate a full-cycle effect. The symmetry properties of the LED filament 100 are as follows.

The definition of the symmetrical characteristic of the LED filament 100 may be based on four quadrants as defined in a top view of the LED bulb. Four quadrants may be defined in a top view of an LED bulb (e.g., the LED bulb 20c of fig. 13A), the origins of which may be defined as the centers of the stem or pole of the LED bulb in the top view (e.g., the top center of the pole 19a of fig. 13A). The LED filament of an LED bulb, such as LED filament 100 of fig. 13A, may exhibit a ring-shaped structure, shape, or contour in a top view. The LED filaments appearing in the four quadrants in the top view will have symmetry.

For example, when the LED filament is operated, the brightness of the LED filament in the first quadrant in the top view is symmetrical to the brightness of the LED filament in the second, third or fourth quadrant in the top view. In some embodiments, the structure of the portion of the LED filament in the first quadrant in the top view will be symmetrical to the structure of the portion of the LED filament in the second, third, or fourth quadrant in the top view. In addition, the light emitting direction of the part of the LED filament in the first quadrant in the top view is symmetrical to the light emitting direction of the part of the LED filament in the second quadrant, the third quadrant or the fourth quadrant in the top view.

In other embodiments, the arrangement of the LED chips in the portion of the LED filament in the first quadrant in the top view (e.g., the density variation of the LED chips in the portion of the LED filament in the first quadrant) may be symmetrical to the arrangement of the LED chips in the portion of the LED filament in the second, third, or fourth quadrant in the top view.

In other embodiments, the power arrangement of the LED chips with different powers of the LED filament in the portion of the first quadrant in the top view (e.g., the position distribution of the LED chips with different powers of the LED filament in the portion of the first quadrant) may be symmetrical to the power arrangement of the LED chips with different powers of the LED filament in the portion of the second quadrant, the third quadrant, or the fourth quadrant in the top view.

In other embodiments, when the LED filament is distinguishable as segments and the segments are defined by refractive indices that are distinguishable from one another, the refractive index of the segments of the LED filament in the first quadrant of the top view will be symmetric with respect to the refractive index of the segments of the LED filament in the second, third, or fourth quadrant of the top view.

In other embodiments, when the LED filament is distinguishable into segments and the segments are defined by surface roughness that is distinguishable from each other, the surface roughness of the segments of the LED filament in the first quadrant of the top view will be symmetrical to the surface roughness of the segments of the LED filament in the second, third or fourth quadrant of the top view.

The LED filaments present in the four quadrants of the top view may be point symmetric (e.g., symmetric according to the origin of the four quadrants) or line symmetric (e.g., symmetric according to one of the two axes of the four quadrants).

The symmetrical structure of the LED filament in the four quadrants of the top view may have an error of at most 20% -50%, for example, when the structure of the portion of the LED filament in the first quadrant is symmetrical to the structure of the portion of the LED filament in the second quadrant, the LED filament has a designated point on the portion of the first quadrant, and the LED filament has a symmetrical point symmetrical to the designated point on the portion of the second quadrant, the designated point has a first position, the symmetrical point has a second position, and the first position and the second position may be completely symmetrical or have an error of 20% -50%.

In addition, in a top view, when the LED filament is symmetrical in two quadrants, it can also be defined that the length of the part of the LED filament in one quadrant is substantially equal to the length of the part of the LED filament in the other quadrant. The lengths of the portions of the LED filament in the different quadrants may also have an error of 20% -50%. Wherein the length may be a length of the LED filament extending along an axial direction thereof.

The definition of the symmetrical characteristic of the LED filament 100 may be based on four quadrants defined by the LED bulb in side, front, or rear views. In the present embodiment, the side view of the LED bulb lamp includes a front view or a rear view. In a side view of an LED bulb (e.g., the LED bulb 20c of fig. 13A), four quadrants may be defined, in which case, an extension direction (from the lamp head 16 toward a top end of the lamp housing 12 away from the lamp head 16) of a stem or a rod (e.g., the rod 19a of the LED bulb 20c of fig. 13A) in the LED bulb may be defined as a Y-axis, and an X-axis may traverse a middle of the rod, where an origin of the four quadrants is defined as a middle of the rod, i.e., an intersection of the X-axis and the Y-axis. In various embodiments, the X-axis may traverse any point of the upright, for example, the X-axis may traverse a top end of the upright, a bottom end of the upright, or a point at a particular height of the upright (e.g., at 2/3).

In addition, the parts of the LED filament in the first quadrant and the second quadrant (upper quadrant) in the side view are symmetrical in brightness (for example, line symmetry is formed for the Y axis); the LED filaments, which are positioned in the third and fourth quadrants (lower quadrants) in the side view, are symmetrical in brightness (e.g., line-symmetrical about the Y-axis). However, the brightness exhibited by the portion of the LED filament in the upper quadrant in side view is not symmetrical to the brightness exhibited by the portion of the LED filament in the lower quadrant in side view.

In some embodiments, the portions of the LED filaments in the first quadrant and the second quadrant (i.e., the upper two quadrants) are structurally symmetrical (e.g., line symmetry with the Y-axis as the line of symmetry). The portions of the LED filaments in the third and fourth quadrants (i.e., the lower two quadrants) are also structurally symmetrical (e.g., line symmetry with the Y-axis as the symmetry line). In addition, the light emitting direction of the part of the LED filament in the first quadrant in the side view is symmetrical to the light emitting direction of the part of the LED filament in the second quadrant in the side view; the light emitting direction of the part of the LED filament in the third quadrant in the side view is symmetrical to the light emitting direction of the part of the LED filament in the fourth quadrant in the side view.

In other embodiments, the arrangement of the LED chips on the portion of the LED filament in the first quadrant in side view may be symmetrical to the arrangement of the LED chips on the portion of the LED filament in the second quadrant in side view; the arrangement of the LED chips on the portion of the LED filament in the third quadrant in the side view will be symmetrical to the arrangement of the LED chips on the portion of the LED filament in the fourth quadrant in the side view.

In other embodiments, the power arrangement of LED chips with different powers of the LED filament on the part of the first quadrant in the side view will be symmetrical to the power arrangement of LED chips with different powers of the LED filament on the part of the second quadrant in the side view; the power arrangement of the LED chips with different powers of the LED filament on the portion of the third quadrant in the side view will be symmetrical to the power arrangement of the LED chips with different powers of the LED filament on the portion of the fourth quadrant in the side view.

In other embodiments, when the LED filament is distinguishable into segments and the segments are defined by refractive indices that are distinguishable from one another, the refractive index of the segments of the LED filament in the first quadrant portion in side view will be symmetric to the refractive index of the segments of the LED filament in the second quadrant portion in side view; the refractive index of the plurality of segments of the LED filament in the third quadrant of the side view will be symmetrical to the refractive index of the plurality of segments of the LED filament in the fourth quadrant of the side view.

In other embodiments, when the LED filament is distinguishable into segments and the segments are defined by surface roughnesses that are distinguishable from one another, the surface roughness of the segments of the LED filament in side view on the portion of the first quadrant is symmetrical to the surface roughness of the segments of the LED filament in side view on the portion of the second quadrant; the surface roughness of the plurality of segments of the LED filament in the third quadrant of the side view is symmetrical to the surface roughness of the plurality of segments of the LED filament in the fourth quadrant of the side view.

In addition, in a side view, the portions of the LED filament appearing in the upper two quadrants and the portions of the LED filament appearing in the lower two quadrants are asymmetrical in brightness. In some embodiments, the portions of the LED filament present in the first quadrant and the fourth quadrant are asymmetric in structure, in length, in light exit direction, in configuration of the LED chips, in power arrangement of the LED chips with different power, in refractive index, or in surface roughness, while the portions of the LED filament present in the second quadrant and the third quadrant are asymmetric in structure, in length, in light exit direction, in configuration of the LED chips, in power arrangement of the LED chips with different power, in refractive index, or in surface roughness. To meet the lighting objectives and requirements of a full-perimeter light fixture, more light should be emitted from the upper quadrant (the portion away from the base 16) than from the lower quadrant (the portion closer to the base 16) in side view. Therefore, the asymmetric characteristic between the upper quadrant and the lower quadrant of the LED filament of the LED bulb lamp can help to meet the requirement of full-cycle light by concentrating light rays in the upper quadrant.

The symmetrical configuration of the LED filament in the first and second quadrants of the side view may have an error (tolerance) of 20% -50%, for example, the LED filament has a designated point on the portion of the first quadrant and the LED filament has a symmetrical point symmetrical to the designated point on the portion of the second quadrant, the designated point has a first position, the symmetrical point has a second position, the first and second positions may be completely symmetrical or have an error of 20% -50%. The meaning of the error herein can be referred to the above description.

Further, in a side view, the length of the portion of the LED filament in the first quadrant may be substantially equal to the length of the portion of the LED filament in the second quadrant. In a side view, the length of the portion of the LED filament in the third quadrant will be substantially equal to the length of the portion of the LED filament in the fourth quadrant. However, in a side view, the length of the portion of the LED filament in the first quadrant or the second quadrant may be different from the length of the portion of the LED filament in the third quadrant or the fourth quadrant. In some embodiments, in a side view, the length of the portion of the LED filament in the third quadrant or the fourth quadrant may be less than the length of the portion of the LED filament in the first quadrant or the second quadrant. In a side view, the length of the portion of the LED filament in the first quadrant or the second quadrant or the length of the portion of the LED filament in the third quadrant or the fourth quadrant may also have an error of 20% -50%.

Referring to fig. 14D, fig. 14D shows the LED filament 100 of fig. 14B in a two-dimensional coordinate system defining four quadrants. The LED filament 100 of fig. 14D is identical to the LED filament 100 of fig. 14B, and fig. 14D is a front view (or side view) of the LED bulb 20D of fig. 14A. As shown in fig. 14B and 14D, the Y-axis is aligned with the leg 19a of the stem (i.e., the Y-axis is located in the extending direction of the leg 19a), and the X-axis crosses the leg 19a (i.e., the X-axis is perpendicular to the extending direction of the leg 19 a). As shown in fig. 14D, the LED filament 100 is divided into a first portion 100p1, a second portion 100p2, a third portion 100p3 and a fourth portion 100p4 by the X axis and the Y axis in a side view. The first portion 100p1 of the LED filament 100 is a portion appearing in a first quadrant in a side view, the second portion 100p2 of the LED filament 100 is a portion appearing in a second quadrant in a side view, the third portion 100p3 of the LED filament 100 is a portion appearing in a third quadrant in a side view, and the fourth portion 100p4 of the LED filament 100 is a portion appearing in a fourth quadrant in a side view.

As shown in fig. 14D, the LED filament 100 is line symmetric. The LED filament 100 is symmetrical with respect to the Y axis in a side view, that is, the geometries of the first portion 100p1 and the fourth portion 100p4 are symmetrical to the geometries of the second portion 100p2 and the third portion 100p 3. Specifically, the first portion 100p1 is symmetrical to the second portion 100p2 in side view, and further, the first portion 100p1 and the second portion 100p2 are symmetrical in structure with respect to the Y-axis in side view. In addition, the third portion 100p3 is symmetrical to the fourth portion 100p4 in side view, and further, the third portion 100p3 and the fourth portion 100p4 are symmetrical in structure with respect to the Y axis in side view.

In the present embodiment, as shown in fig. 14D, the first portion 100p1 and the second portion 100p2 located in the upper quadrant (i.e., the first quadrant and the second quadrant) in the side view and the third portion 100p3 and the fourth portion 100p4 located in the lower quadrant (i.e., the third quadrant and the fourth quadrant) in the side view are asymmetric. Specifically, the first portion 100p1 and the fourth portion 100p4 are asymmetrical in side view, and the second portion 100p2 and the third portion 100p3 are asymmetrical in side view. According to the asymmetric characteristic of the structure of the LED filament 100 in fig. 14D in the upper quadrant and the lower quadrant, the light emitted from the upper quadrant and passing through the upper lamp housing 12 (the portion far from the lamp cap 16) is more than the light emitted from the lower quadrant and passing through the lower lamp housing 12 (the portion near the lamp cap 16), so as to meet the illumination purpose and requirement of the full-circle light fixture.

Based on the symmetrical characteristic of the LED filament 100, the structure of the two symmetrical portions of the LED filament 100 in the side view (the first portion 100p1 and the second portion 100p2 or the third portion 100p3 and the fourth portion 100p4) may be completely symmetrical or symmetrical with errors in structure. The error (tolerance) between the structures of the two symmetrical portions of the LED filament 100 in the side view may be 20% -50% or less.

The error may be defined as a difference in coordinates (i.e., an x-coordinate and a Y-coordinate), for example, if the LED filament 100 has a designated point on the first portion 100p1 of the first quadrant and the LED filament 100 has a symmetrical point symmetrical to the designated point with respect to the Y-axis on the second portion 100p2 of the second quadrant, the absolute value of the Y-coordinate or the x-coordinate of the designated point may be equal to the absolute value of the Y-coordinate or the x-coordinate of the symmetrical point, or may have a difference of 20% with respect to the absolute value of the Y-coordinate or the x-coordinate of the symmetrical point.

For example, as shown in fig. 14D, one designated point (x1, Y1) of the LED filament 100 in the first part 100p1 of the first quadrant is defined as a first position, one symmetric point (x2, Y2) of the LED filament 100 in the second part 100p2 of the second quadrant is defined as a second position, and the second position of the symmetric point (x2, Y2) is symmetric to the first position of the designated point (x1, Y1) with respect to the Y axis. The first and second positions may be completely symmetrical or symmetrical with a 20% -50% error. In the present embodiment, the first portion 100p1 and the second portion 100p2 are completely symmetrical in structure, that is, x2 of the symmetrical points (x2, y2) is equal to negative x1 of the designated points (x1, y1), and y2 of the symmetrical points (x2, y2) is equal to y1 of the designated points (x1, y 1).

For example, as shown in fig. 14D, one designated point (x3, Y3) of the LED filament 100 in the third portion 100p3 of the third quadrant is defined as a third position, one symmetric point (x4, Y4) of the LED filament 100 in the fourth portion 100p4 of the fourth quadrant is defined as a fourth position, and the fourth position of the symmetric point (x4, Y4) is symmetric with respect to the Y axis to the third position of the designated point (x3, Y3). The third and fourth positions may be completely symmetrical or symmetrical with a 20% -50% error. In the present embodiment, the third portion 100p3 and the fourth portion 100p4 are symmetrical with respect to the structural error (for example, there may be an error smaller than 20% in coordinates), that is, the absolute value of x4 of the symmetrical point (x4, y4) is not equal to the absolute value of x3 of the designated point (x3, y3), and the absolute value of y4 of the symmetrical point (x4, y4) is not equal to the absolute value of y3 of the designated point (x3, y 3). As shown in fig. 14D, the vertical height of the designated point (x3, Y3) is slightly lower than the vertical height of the symmetry point (x4, Y4), and the designated point (x3, Y3) is closer to the Y-axis than the symmetry point (x4, Y4). Accordingly, the absolute value of y4 is slightly less than the absolute value of y3, while the absolute value of x4 is slightly greater than the absolute value of x 3.

As shown in fig. 14D, the length of the first portion 100p1 of the first quadrant of the LED filament 100 in side view is substantially equal to the length of the second portion 100p2 of the second quadrant of the LED filament 100 in side view. In this embodiment, the length is defined along the elongation of the LED filament 100 in a plan view (e.g., a side, front, or top view). For example, the first portion 100p1 is elongated in the first quadrant of the side view of fig. 14D to form an inverted "V" shape having two ends contacting the X-axis and the Y-axis, respectively, and the length of the first portion 100p1 is defined along the inverted "V" shape between the X-axis and the Y-axis.

Furthermore, the length of the third portion 100p3 of the third quadrant of the LED filament 100 in side view is substantially equal to the length of the fourth portion 100p4 of the fourth quadrant of the LED filament 100 in side view. Since the third portion 100p3 and the fourth portion 100p4 are in error-symmetrical with each other in structure with respect to the Y-axis, the length of the third portion 100p3 is slightly different from the length of the fourth portion 100p 4. This error may be 20% -50% or less.

As shown in fig. 14D, in the side view, the light exit direction of a specified point of the first portion 100p1 and the light exit direction of a point of symmetry of the second portion 100p2 are symmetrical in direction with respect to the Y axis. In this embodiment, the light emitting direction may be defined as a direction in which the LED chip faces. And the direction in which the LED chips face is defined as the direction in which the main light emitting surface Lm faces, the light outgoing direction can also be defined as the normal direction of the main light emitting surface Lm. For example, the light exit direction ED of a specified point (x1, y1) of the first portion 100p1 is upward in fig. 14D, and the light exit direction ED of a symmetrical point (x2, y2) of the second portion 100p2 is upward in fig. 14D. The light exit direction ED of the designated point (x1, Y1) and the light exit direction ED of the point of symmetry (x2, Y2) are symmetrical with respect to the Y axis. Further, the light outgoing direction ED of a specified point (x3, y3) of the third portion 100p3 is a lower left direction in fig. 14D, and the light outgoing direction ED of a symmetrical point (x4, y4) of the fourth portion 100p4 is a lower right direction in fig. 14D. The light exit direction ED of the designated point (x3, Y3) and the light exit direction ED of the point of symmetry (x4, Y4) are symmetrical with respect to the Y axis.

Referring to fig. 14E, fig. 14E shows the LED filament 100 of fig. 14C in a two-dimensional coordinate system defining four quadrants. The LED filament 100 of fig. 14E is identical to the LED filament 100 of fig. 14C, and fig. 14E is a top view of the LED bulb 20d of fig. 14A. As shown in fig. 14C and 14E, the origin of the four quadrants is defined as the center of the stem 19a of the LED bulb 20d in top view (e.g., the top center of the stem 19a of fig. 14A). In this embodiment, the Y-axis is vertical in fig. 14E, and the X-axis is horizontal in fig. 14E. As shown in fig. 14E, the LED filament 100 is divided into a first portion 100p1, a second portion 100p2, a third portion 100p3 and a fourth portion 100p4 by the X axis and the Y axis in a top view. The first portion 100p1 of the LED filament 100 is a portion appearing in a first quadrant in a top view, the second portion 100p2 of the LED filament 100 is a portion appearing in a second quadrant in a top view, the third portion 100p3 of the LED filament 100 is a portion appearing in a third quadrant in a top view, and the fourth portion 100p4 of the LED filament 100 is a portion appearing in a fourth quadrant in a top view.

In some embodiments, the LED filament 100 in a top view may be point symmetric (e.g., symmetric according to the origin of the four quadrants) or line symmetric (e.g., symmetric according to one of the two axes of the four quadrants). In the present embodiment, as shown in fig. 14E, the LED filament 100 is line-symmetric in the top view, and particularly, the LED filament 100 is symmetric with respect to the Y axis in the top view, that is, the geometries of the first portion 100p1 and the fourth portion 100p42 are symmetric with respect to the geometries of the second portion 100p2 and the third portion 100p 3. Specifically, the first portion 100p1 is symmetrical to the second portion 100p2 in top view, and further, the first portion 100p1 and the second portion 100p2 are symmetrical in structure with respect to the Y-axis in top view. In addition, the third portion 100p3 is symmetrical to the fourth portion 100p4 in top view, and further, the third portion 100p3 and the fourth portion 100p4 are symmetrical in structure with respect to the Y axis in top view.

Based on the symmetrical characteristic of the LED filament 100, the structure of the two symmetrical portions of the LED filament 100 (the first portion 100p1 and the second portion 100p2 or the third portion 100p3 and the fourth portion 100p4) in the top view may be completely symmetrical or symmetrical with errors in structure. The error (tolerance) between the structures of the two symmetrical portions of the LED filament 100 in the top view may be 20% -50% or less.

For example, as shown in fig. 14E, one designated point (x1, Y1) of the LED filament 100 in the first part 100p1 of the first quadrant is defined as a first position, one symmetric point (x2, Y2) of the LED filament 100 in the second part 100p2 of the second quadrant is defined as a second position, and the second position of the symmetric point (x2, Y2) is symmetric to the first position of the designated point (x1, Y1) with respect to the Y axis. The first and second positions may be completely symmetrical or symmetrical with a 20% -50% error. In the present embodiment, the first portion 100p1 and the second portion 100p2 are completely symmetrical in structure, that is, x2 of the symmetrical points (x2, y2) is equal to negative x1 of the designated points (x1, y1), and y2 of the symmetrical points (x2, y2) is equal to y1 of the designated points (x1, y 1).

For example, as shown in fig. 14E, one designated point (x3, Y3) of the LED filament 100 in the third portion 100p3 of the third quadrant is defined as a third position, one symmetric point (x4, Y4) of the LED filament 100 in the fourth portion 100p4 of the fourth quadrant is defined as a fourth position, and the fourth position of the symmetric point (x4, Y4) is symmetric with respect to the Y axis to the third position of the designated point (x3, Y3). The third and fourth positions may be completely symmetrical or symmetrical with a 20% -50% error. In the present embodiment, the third portion 100p3 and the fourth portion 100p4 are symmetrical with errors in structure (for example, there may be an error less than 20% in coordinates), that is, x4 of the symmetrical point (x4, y4) is not equal to the negative value of x3 of the designated point (x3, y3), and y4 of the symmetrical point (x4, y4) is not equal to y3 of the designated point (x3, y 3). As shown in fig. 14E, the vertical height of the designated point (x3, Y3) is slightly lower than the vertical height of the symmetry point (x4, Y4), and the designated point (x3, Y3) is closer to the Y-axis than the symmetry point (x4, Y4). Accordingly, the absolute value of y4 is slightly less than the absolute value of y3, while the absolute value of x4 is slightly greater than the absolute value of x 3.

As shown in fig. 14E, the length of the first portion 100p1 of the first quadrant of the LED filament 100 in the top view is substantially equal to the length of the second portion 100p2 of the second quadrant of the LED filament 100 in the top view. In this embodiment, the length is defined along the elongation of the LED filament 100 in a plan view (e.g., top, front, or side view). For example, second portion 100p2 is elongated in the second quadrant of the top view of FIG. 14E to form an inverted "L" shape having two ends that contact the X-axis and Y-axis, respectively, and the length of second portion 100p2 is defined along the inverted "L" shape.

Furthermore, the length of the third portion 100p3 of the third quadrant of the LED filament 100 in top view is substantially equal to the length of the fourth portion 100p4 of the fourth quadrant of the LED filament 100 in top view. Since the third portion 100p3 and the fourth portion 100p4 are in error-symmetrical with each other in structure with respect to the Y-axis, the length of the third portion 100p3 is slightly different from the length of the fourth portion 100p 4. This error may be 20% -50% or less.

As shown in fig. 14E, in a top view, the light exit direction of a specified point of the first portion 100p1 and the light exit direction of a point of symmetry of the second portion 100p2 are symmetrical in direction with respect to the Y axis. In this embodiment, the light emitting direction may be defined as a direction in which the LED chip faces. And the direction in which the LED chips face is defined as the direction in which the main light emitting surface Lm faces, the light outgoing direction can also be defined as the normal direction of the main light emitting surface Lm. For example, the light exit direction ED of a specified point (x1, y1) of the first portion 100p1 is rightward in fig. 14E, and the light exit direction ED of a symmetrical point (x2, y2) of the second portion 100p2 is leftward in fig. 14E. The light exit direction ED of the designated point (x1, Y1) and the light exit direction ED of the point of symmetry (x2, Y2) are symmetrical with respect to the Y axis. Further, the light outgoing direction ED of a specified point (x3, y3) of the third portion 100p3 is a lower left direction in fig. 14E, and the light outgoing direction ED of a symmetrical point (x4, y4) of the fourth portion 100p4 is a lower right direction in fig. 14E. The light exit direction ED of the designated point (x3, Y3) and the light exit direction ED of the point of symmetry (x4, Y4) are symmetrical with respect to the Y axis. In addition, in a top view, the light-emitting direction ED of any given point on the first portion 100p1 and the light-emitting direction ED of any corresponding symmetric point on the second portion 100p2, which is symmetric to the given point, are directionally symmetric with respect to the Y-axis. In a top view, the light-emitting direction ED of any given point on the third portion 100p3 and the light-emitting direction ED of any corresponding symmetric point on the fourth portion 100p4, which is symmetric to the given point, are symmetric in direction with respect to the Y-axis.

As described in the foregoing embodiments, in the side view (including the front view or the rear view) and/or the top view, the symmetrical characteristics of the LED filament 100 with respect to the symmetrical structure, the symmetrical light emitting direction, the symmetrical configuration of the LED chips 442, the symmetrical power arrangement of the LED chips 442, the symmetrical refractive index and/or the symmetrical surface roughness are helpful for generating uniformly distributed light, and the symmetrical design of the symmetrical power arrangement, the symmetrical refractive index and/or the symmetrical surface roughness of the LED chips 442 can be comprehensively considered by matching with the sectional characteristics of the LED filament, so that the LED bulb lamp with the LED filament 100 can generate full ambient light.

While the present invention has been disclosed in terms of the preferred embodiment, it will be understood by those skilled in the art that this embodiment is provided for illustration only, and should not be construed as limiting the scope of the invention. It should be noted that equivalent changes and substitutions to those of the embodiment are also intended to be included within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the appended claims.

Claims

1. An LED filament, wherein the LED filament is located in a planar orthogonal coordinate system (X, Y), wherein the X-axis is parallel to the length direction of the LED filament, the LED filament comprising:

2. The LED filament according to claim 1, wherein any two adjacent LED chip units are electrically connected to each other through a conductor, and an included angle between the conductor and the X-axis direction is 30-120 °.

3. The LED filament of claim 2, wherein the conductor is a copper foil, gold foil, or gold wire.

4. The LED filament of claim 1, wherein any of said plurality of LED chip units comprises at least one LED chip.

5. The LED filament according to claim 4, wherein the length direction of the LED chip is parallel to the X-axis direction.

6. The LED filament of claim 1, wherein the wire is parallel to the X-axis direction or the included angle between the wire and the X-axis direction is 30-120 °.

7. The LED filament of claim 1, wherein the number of the wires is 2, and both of the wires are parallel to the X-axis direction.

8. The LED filament of claim 1, further comprising a light conversion layer covering the plurality of LED chip units and the electrodes and respectively exposing a portion of the two electrodes.

9. An LED bulb lamp is characterized by comprising a lamp holder, a lamp shell and an LED filament according to any one of claims 1-8, wherein the lamp holder is connected with the lamp shell, the lamp shell is made of a light-transmitting material, and the LED filament is located in the lamp shell.

10. The LED bulb lamp according to claim 9, wherein a yellow film is plated on the surface of the lamp housing.