CN214147468U - LED filament and LED bulb - Google Patents
LED filament and LED bulb Download PDFInfo
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- CN214147468U CN214147468U CN202022600267.8U CN202022600267U CN214147468U CN 214147468 U CN214147468 U CN 214147468U CN 202022600267 U CN202022600267 U CN 202022600267U CN 214147468 U CN214147468 U CN 214147468U
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Abstract
The application discloses an LED filament, which comprises an LED section, wherein the LED section comprises at least two LED chips, and each LED chip comprises GaN and a substrate; the conductor section is electrically connected with the two adjacent LED sections; the light conversion layer comprises a top layer and a base layer, the top layer is coated on at least two sides of the LED chip, solid crystal glue is arranged between the base layer and the LED chip, light emitted by the LED chip passes through an interface A, an interface C, an interface D and an interface F, the interface A is an interface of GaN and the top layer in the LED chip, the interface C is an interface of a substrate and the solid crystal glue in the LED chip, the interface D is an interface of the solid crystal glue and the base layer, the interface F is an interface of the base layer and the top layer, the refractive indexes of two substances in any interface are n1 and n2 respectively, and the absolute value of the difference value between n1 and n2 is smaller than 0.5. The bulb lamp using the LED filament is further disclosed.
Description
The utility model discloses the application is the divisional application of 2018 12 month 26 day application, application number 201822198239.0, practical 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.
In addition, the LED filament is generally disposed in the LED bulb, and in order to present an aesthetic feeling in appearance and to make an illumination effect of the LED filament more uniform and wide, the LED filament may be bent to present various curves. However, the LED filament has LED chips arranged therein, and the LED chips are relatively hard objects, so that the LED filament is difficult to bend into a desired shape. Further, the LED filament is also prone to cracking due to stress concentration during bending.
The existing LED bulb lamp is provided with a plurality of LED lamp filaments in order to increase aesthetic feeling in appearance and enable illumination effect to be more uniform, and the LED lamp filaments are set to be different placing angles. However, since a plurality of LED filaments need to be installed in a single LED bulb, and the LED filaments need to be individually fixed, the manufacturing process is more complicated, and the production cost is increased.
In addition, the driving requirement of the LED filament for lighting is substantially different from that of the traditional tungsten filament lamp. For an LED bulb, it is a design consideration how to design a power circuit to provide a stable current to make the ripple of the LED filament low enough when the LED filament is turned on, so that a user does not feel flickering. Secondly, due to the limitation of space, it is also a significant concern how to design a power circuit that is simple enough and can accommodate the space of the lamp holder on the premise of realizing the required lighting effect and the driving requirement.
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.
According to an embodiment of the present invention, an LED filament is disclosed, comprising an LED segment, said LED segment comprising at least two LED chips, said LED chips comprising GaN and a substrate; the conductor section is electrically connected with the two adjacent LED sections; the light conversion layer comprises a top layer and a base layer, the top layer is coated on at least two sides of the LED chip, solid crystal glue is arranged between the base layer and the LED chip, light emitted by the LED chip passes through an interface A, an interface C, an interface D and an interface F, the interface A is an interface of GaN and the top layer in the LED chip, the interface C is an interface of a substrate and the solid crystal glue in the LED chip, the interface D is an interface of the solid crystal glue and the base layer, the interface F is an interface of the base layer and the top layer, the refractive indexes of two adjacent substances of any interface are n1 and n2 respectively, and the absolute value of the difference value between n1 and n2 is smaller than 1.
Optionally, the absolute value of the difference between n1 and n2 is less than 0.2.
Optionally, D, F the absolute value of the difference in refractive index between the two substances at either of the two interfaces is less than 0.5.
Optionally, D, F the absolute value of the difference between the refractive indices of the two substances at either of the two interfaces is less than 0.2.
Optionally, the conductor segment includes a conductor, a maximum thickness of the LED chip in the radial direction of the filament is H, and a thickness of the conductor in the radial direction of the LED filament is 0.5H to 1.4H.
Optionally, the shortest distance between two LED chips respectively located in two adjacent LED segments is greater than the distance between two adjacent LED chips in any one of the LED segments.
Optionally, the length of the conductor segment is greater than the distance between two adjacent LED chips in any one of the LED segments.
The utility model discloses a LED bulb lamp, LED bulb lamp includes: the lamp shell is filled with inert gas; the lamp holder is connected with the lamp shell; the LED lamp comprises at least one LED filament, wherein light emitted by the LED chip passes through an interface A, an interface B, an interface C, an interface D, an interface E and an interface F, the interface B is an interface between the top layer of the light conversion layer and inert gas, the interface E is an interface between the base layer of the light conversion layer and inert gas, and the absolute value of the difference between the refractive indexes of any two adjacent substances is smaller than 1.
Optionally, B, E, D, F the absolute value of the difference between the refractive indices of two substances adjacent to any of the four interfaces is less than 0.5.
Optionally, B, E, D, F the absolute value of the difference between the refractive indices of two substances adjacent to any of the four interfaces is less than 0.2.
The utility model discloses owing to adopted above technical scheme, can reach at least following one of beneficial effect or its arbitrary combination: (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 LED filament structure is designed through an ideal formula, so that the overall luminous efficiency can be improved; (4) the organic silicon modified polyimide resin composition prepared by adding a thermal curing agent into organic silicon modified polyimide serving as a main body has excellent heat resistance, mechanical strength and light transmittance; the organic silicon modified polyimide resin composition is used as the filament substrate, and the filament has good flexibility, so that the filament presents various shapes, and 360-degree full-circumference illumination is realized; (5) the LED bulb lamp comprises a single LED filament, and the LED filament has a symmetrical characteristic, so that the symmetrical characteristic is beneficial to generating uniform and wide light distribution, and the LED bulb lamp can generate the effect of full-cycle light; and (6) the power supply circuit can provide stable current to ensure that the ripple of the LED filament is low enough when the LED filament is lighted, so that a user does not feel flickering.
Drawings
Fig. 1A and 1B are schematic diagrams illustrating an LED bulb according to an embodiment of 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 2J are schematic structural diagrams of various embodiments of the segmented LED filament according to the present invention;
fig. 3 is a schematic view of an interface through which light emitted from the LED chip of the present invention passes;
FIG. 4 is a graph showing a distribution of sizes of heat dissipating particles of different specifications;
FIG. 5A is a SEM image of a composite film of the silicone-modified polyimide resin composition of the present invention;
FIGS. 5B and 5C are schematic cross-sectional views of composite films made of the silicone-modified polyimide resin composition according to embodiments of the present invention;
fig. 6 is a schematic diagram of an LED bulb lamp using the LED filament of the present invention;
fig. 7A to 7D are a schematic diagram, a side view, another side view and a top view, respectively, of an LED bulb according to an embodiment of the present invention;
fig. 8A to 8C are schematic diagrams of an LED filament circuit according to an embodiment of the present invention;
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.
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.
Referring to fig. 1A and 1B, fig. 1A and 1B are schematic structural diagrams of a first embodiment and a second embodiment of the present invention. As can be seen from the figure, the LED bulb lamps 1a and 1b include a lamp housing 12, a lamp cap 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 disposed in the lamp cap and electrically connecting the conductive brackets 51a and 51b and the lamp cap 16, and a single light emitting portion 100 disposed in the lamp housing 12, where the light emitting portion 100 may be an LED filament including an LED chip.
The conductive supports 51a and 51b are used to electrically connect the two electrodes 506 of the light-emitting portion 100, and also to support the weight of the light-emitting portion 100. The driving circuit 518 is electrically connected to the conductive brackets 51a and 51b and the lamp head 16, when the lamp head 16 is connected to a lamp socket of a conventional bulb lamp, the lamp socket provides power to the lamp head 16, and the driving circuit 518 is used for driving the light-emitting portion 100 to emit light after receiving power from the lamp head 16. Due to the symmetrical characteristic of the light emitting part 100 of the LED bulb lamps 1a and 1b in terms of structure, shape, contour, curve, etc., or the symmetrical characteristic of the light emitting part 100 in the light emitting direction (the direction toward which the light emitting surface of the LED filament faces in the present invention) (as described in detail later), the LED bulb lamps 1a and 1b can generate full-circle light. In the present embodiment, the driving circuit 518 is disposed inside the LED bulb. However, in some embodiments, the driver circuit 518 is disposed external to the LED bulb.
In the embodiment of fig. 1A, two conductive brackets 51A and 51b of the LED bulb lamp 1A are taken as an example, but not limited thereto, and the number of the conductive brackets is increased according to the conductive or supporting requirement of the light emitting part 100.
In the embodiment shown in fig. 1A and 1B, the LED bulbs 1A and 1B further include a stem 19 and a heat dissipation assembly 17, the stem 19 is disposed in the lamp housing 12, and the heat dissipation assembly 17 is located between the lamp cap 16 and the lamp housing 12 and is connected to the stem 19. In this embodiment, the base 16 is indirectly connected to the lamp housing 12 through the heat dissipation assembly 17. In other embodiments, the base 16 may be directly attached to the lamp envelope 12 without the heat sink assembly 17. The light emitting section 100 is connected to the stem 19 via the conductive brackets 51a, 51 b. The stem 19 can be used for replacing air in the LED bulb lamp 1b with a mixture of nitrogen and helium. The stem 19 can also provide a heat conducting function, which conducts heat from the light emitting part 100 connected to the stem 19 to the outside of the lamp envelope 12. The heat sink 17 may be a hollow cylinder surrounding the opening of the lamp housing 12, and connects the stem 19 and the base 16 to conduct heat therefrom to the outside of the LED bulb 1 b. The driving circuit 518 may be installed inside the heat sink 17, and the outside of the heat sink 17 may be in contact with the external air to conduct heat. The material of the heat dissipation assembly 17 can be selected from metal, ceramic or high thermal conductivity plastic with good thermal conductivity. The heat dissipation assembly 17 (together with the opening/screw of the LED bulb) may also be made of a ceramic material with a good heat conduction effect, and the heat dissipation assembly 17 may also be an integrally formed assembly with the ceramic stem 19, so that the heat resistance of the heat dissipation path of the light emitting part 100 due to the fact that the lamp cap of the LED bulb needs to be glued with the heat dissipation assembly 17 can be avoided, and a better heat dissipation effect is achieved.
The LED chip units 102 and 104, or the LED segments 102 and 104, may be a single LED chip, two LED chips, or multiple LED chips, that is, equal to or greater than three LED chips.
Referring to fig. 2A to fig. 2G, 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 402,404 or the conductor segment 430 in the radial direction of the LED filament, or the thickness, diameter or width of the top layer of the LED segments 402,404 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 402,404 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, 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 this embodiment, both the LED segments 402,404 and the conductor segment 430 of the LED filament have different structural characteristics. In the present embodiment, the LED segments 402,404 and the conductor segment 430 have different widths, thicknesses or diameters in the radial direction of the LED filament. As shown in fig. 2C, the conductor segments 430 are thin relative to the LED segments 402,404, the conductor segments 430 serve as the primary bending portion when the LED filament is bent, and the thin conductor segments 430 help to be bent into a variety of curves. In this embodiment, the base layer 420b, whether in the LED segments 402,404 or in the conductor segment 430, is uniform in width, thickness or diameter in the radial direction of the LED filament; while the top layer 420a has a different width, thickness or diameter in the radial direction of the LED filament between the LED segments 402,404 and the conductor segment 430. As shown in fig. 2C, the top layer 420a of the LED segments 402,404 has the largest diameter D2 in the radial direction of the LED filament, and the top layer 420a of the conductor segment 430 has the largest diameter D1 in the radial direction of the LED filament, D2 being larger than D1. The diameter of the top layer 420a gradually decreases from the LED segments 402 and 404 to the conductor segment 430, and then gradually increases from the conductor segment 430 to the LED segments 402 and 404, so that the top layer 420a forms a smooth and concave curve along the axial direction of the LED filament.
As shown in fig. 2D, 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. 2E, in this embodiment, the top layer 420a, whether in the LED segments 402 and 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 least one conductor 430a, such that a portion (e.g., a middle portion) of at least one conductor 430a is not covered by the base layer 420b, and another at least one conductor 430a is completely covered by the base layer 420 b.
As shown in fig. 2F, in this 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 402,404 or the conductor segments 430, and the base layer 420b is recessed or hollowed out at all of 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. 2G, 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. 2E to 2G, 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. 2H, in the present embodiment, the conductor 430a is, for example, a conductive metal sheet or strip. Conductor 430a has a thickness Tc, and since LED chip 442 is thinner relative to conductor 430a, thickness Tc of conductor 430a is significantly greater than the thickness of LED chip 442. In addition, the thickness Tc of the conductor 430a is closer to the thickness of the top layer 420a in the conductor segment 430 than the thickness of the LED chip 442 (the thickness of the top layer 420a in the conductor segment 430 can refer to the diameter D1 of the top layer 420a in the radial direction), and Tc is (0.7-0.9) D1, preferably Tc is (0.7-0.8) D1. Also, in this embodiment, the thickness of the top layer 420a at the conductor segment 430 is consistent with the thickness of the LED segments 402,404 (the thickness of the top layer 420a at the LED segments 402,404 can refer to the diameter D2 of the top layer 420a in the radial direction).
As shown in fig. 2I, in the present embodiment, the thickness Tc of the conductor 430a is also significantly larger than the thickness of the LED chip 442, and the thickness Tc of the conductor 430a is closer to the thickness (diameter D1) of the top layer 420a at the conductor segment 430 than the thickness of the LED chip 442. Also, in this embodiment, the top layer 420a is not uniform in thickness between the conductor segment 430 and the LED segments 402, 404. As shown in fig. 2I, the top layer 420a of the LED segments 402,404 has the smallest diameter D2 in the radial direction of the LED filament, and the top layer 420a of the conductor segment 430 has the largest diameter D1 in the radial direction of the LED filament, D1 being larger than D2. The diameter of the top layer 420a gradually increases from the LED segments 402 and 404 to the conductor segment 430, and then gradually decreases from the conductor segment 430 to the LED segments 402 and 404, so that the top layer 420a forms a smooth and concave curve along the axial direction of the LED filament.
As shown in fig. 2J, in the present embodiment, the thickness Tc of the conductor 430a is also significantly larger than the thickness of the LED chip 442, however, 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 is gradually reduced 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.
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.
When the LED filament emits light in the LED bulb lamp packaged with inert gas, as shown in fig. 3, 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 die attach adhesive 450, the interface D is an interface between the die attach adhesive 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.
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 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, and the organic group can have an alicyclic hydrocarbon structure of a monocyclic system, or a 2-valent organic group containing an active hydrogen functional group, wherein the active hydrogen functional group is any one or more of a hydroxyl group, an amino group, a carboxyl group, an amide group or a thiol group.
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) (or 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. Fat and oilThe 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.
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 may further contain a phosphor for obtaining a desired light emitting characteristic, and the phosphor may convert the wavelength of light emitted from the light emitting semiconductor, for example, a yellow phosphor may convert blue light into yellow light, and a red phosphor may 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. Organic silicon modified fluorescent powderThe content ratio in the polyimide resin composition can be arbitrarily set according to the desired light-emitting 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 amount of the phosphor is not less than 0.05 times, preferably not less than 0.1 times, and not more than 8 times, and preferably not more than 7 times the weight of the silicone-modified polyimide, for example, the weight of the silicone-modified polyimide is 100 parts by weight, the amount 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 amount 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 the product. 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, simultaneouslyWhen two kinds of fluorescent powder are added, for example, when red fluorescent powder and yellow fluorescent powder are added simultaneously, the adding ratio of the red fluorescent powder to the yellow fluorescent powder is 1: 5-8, and the adding ratio of the red fluorescent powder to the yellow fluorescent powder is 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 of 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 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 the product. 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. 4. Tables 3-2 and fig. 4 show the results of adding 7 kinds of heat dissipating particles with 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 the particle size distribution of fig. 4, the curve of the specification (c) is smooth, the slope is mostly very small, and it is shown 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 normal, 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 and curing are complete.
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. 5B, 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. 5A 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 surfaces shown in fig. 5B and 5A, there are cells 4d in the substrate, the volume percentage of the cells 4d in the substrate 420B is 5-20%, preferably 5-10%, the cross section of the cells 4d is irregular, as shown in fig. 5B, the cross section of the substrate 420B is shown schematically, the dotted line in fig. 5B 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. 5C, 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.
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. 6, fig. 6 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. In other embodiments of the present invention, the lamp housing 12 includes a luminescent material layer (not shown), which can be formed on the inner surface and the outer surface of the lamp housing 12 or even be integrated into the material of the lamp housing 12 according to design requirements or process feasibility.
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. 6 is bent to form a circular-like profile in the top view of fig. 6. In the embodiment of fig. 6, the LED filament 100 can be bent to form a wave shape in side view due to its inclusion of the LED filament structure as described in any of the embodiments of fig. 2. 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.
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 LED filament 100 shown in fig. 6 is bent to form a circle in top view and a wave in 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. 7A and fig. 7B to 7D, fig. 7A is a schematic diagram of an LED bulb lamp 40h according to an embodiment of the present invention, and fig. 7B to 7D are a side view, another side view and a top view of the LED bulb lamp 40h of fig. 7A, respectively. In the present embodiment, the LED bulb 40h includes a lamp housing 12, a base 16 connected to the lamp housing 12, a stem 19, a rod 19a, and a single LED filament 100. The LED filament 100 includes two electrodes 110, 112 at both ends, two LED segments 102, and a single conductor segment 130. In addition, the LED bulb 40h and the single LED filament 100 disposed in the LED bulb 40h may refer to the LED bulb, the LED filament and the related descriptions thereof in the foregoing embodiments, wherein the same or similar components and the connection relationship between the components are not described in detail.
As shown in fig. 7A to 7D, in the present embodiment, there is one conductor segment 130 of the LED filament 100, and there are two LED segments 102 and 104, and every two adjacent LED segments 102 and 104 are connected through the conductor segment 130, and the LED filament 100 is curved in an arc shape in a bending state at a highest point, that is, the LED segments 102 and 104 are curved in an arc shape at the highest point of the LED filament 100, and the conductor segment is also curved in an arc shape at a low point of the LED filament. The LED filament 100 may be defined as a succession of segments following each bent conductor segment 130, with the individual LED segments 102, 104 forming corresponding segments.
Moreover, since the LED filament 100 employs a flexible base layer, and the flexible base layer preferably employs an organic silicon modified polyimide resin composition, the LED segments 102 and 104 themselves also have a certain degree of bending capability. In the present embodiment, the two LED segments 102 are bent to form an inverted U shape, and the conductor segment 130 is located between the two LED segments 102, and the bending degree of the conductor segment 130 is the same as or greater than that of the LED segments 102. That is, the two LED segments 102 are bent into an inverted U shape at the high point of the filament and have a bending radius R1, and the conductor segment 130 is bent at the low point of the filament LED filament 100 and have a bending radius R2, wherein R1 is greater than R2. By virtue of the arrangement of the conductor segments 130, the LED filament 100 can be bent with a small turning radius in a limited space. In one embodiment, the bending points of the LED segments 102 and 104 are at the same height in the Z-direction. In addition, the rod 19a of the present embodiment has a lower height in the Z direction than the rod 19a of the previous embodiment, and the height of the rod 19a corresponds to the height of the conductor segment 130. For example, the lowest portion of the conductor segment 130 may be connected to the top of the rod 19a, so that the overall shape of the LED filament 100 is not easily deformed. In various embodiments, the conductor segments 130 can be connected to each other through a through hole in the top of the upright rod 19a, or the conductor segments 130 can be glued to the top of the upright rod 19a and connected to each other, but is not limited thereto. In one embodiment, the conductor segment 130 and the vertical rod 19a can be connected by a guide wire, for example, a guide wire is led out from the top of the vertical rod 19a to connect the conductor segment 130.
As shown in fig. 7B, in the present embodiment, in the Z direction, the height of the conductor segment 130 is higher than the two electrodes 110 and 112, and the two LED segments 102 extend upward from the two electrodes 110 and 112 to the highest point, and then bend and extend downward to the conductor segment 130 connecting the two LED segments 102. As shown in fig. 7C, in the present embodiment, the profile of the LED filament 100 in the XZ plane is similar to a V shape, that is, the two LED segments 102 extend upward and outward in an oblique manner, and after being bent at the highest point, extend downward and inward in an oblique manner to the conductor segment 130. As shown in fig. 7D, in the present embodiment, the profile of the LED filament 100 in the XY plane has an S-shape. As shown in fig. 7B and 7D, in the present embodiment, the conductor segment 130 is located between the electrodes 110, 112. As shown in fig. 7D, in the present embodiment, the bending point of the LED segment 102, the bending point of the LED segment 104, and the electrodes 110 and 112 are located on a circumference with the conductor segment 130 as a center on the XY plane.
The utility model discloses "a LED filament", "a LED filament" that indicate are formed by connecting jointly in aforementioned conductor section and LED section, have the same and continuous light conversion layer (including the same and continuous top layer or the bottom that forms) to only be provided with at both ends with bulb conductive support electric connection's two conductive electrode, it is promptly to accord with above structure narration the utility model discloses the single LED filament structure of saying.
In some embodiments, the LED filament 100 may have multiple LED segments, the LED chips in the same LED segment are connected in series, and the different LED segments are connected in parallel, wherein the anode of each LED segment may be used as the anode of the LED filament, and the cathode of each LED segment may be used as the cathode of the LED filament and respectively connected to two or more conductive brackets (e.g., fig. 651 a and 51b), and electrically connected to the power module (e.g., 518) through the conductive brackets. As shown in fig. 8A, fig. 8A is a schematic diagram of an LED filament circuit according to an embodiment of the present invention, in which the LED filament 100 has two LED segments 402 and 404, each LED segment 402/404 may include one or more LED chips, the LED chips in the same LED segment 402/404 are connected in series, and the LED segments 402 and 404 have independent current paths (i.e., connected in a shunt manner) after being electrically connected to each other. More specifically, the anodes of the LED segments 402 and 404 of the present embodiment are connected together and serve as the anode P1 of the LED filament 100, the cathode of the LED segment 402 serves as the first cathode N1 of the LED filament 100, and the cathode of the LED segment 402 serves as the second cathode N2 of the LED filament 100. The anode P1, the first cathode N1 and the second cathode N2 of the LED filament 100 are electrically connected to a power module, such as the conductive brackets 51a and 51b and the power module 518 shown in fig. 6, respectively, through the conductive brackets.
More specifically, the electrical connection relationship between the positive electrode P1, the first negative electrode N1, and the second negative electrode N2 of the LED filament 100 and the power module can be as shown in fig. 8B or fig. 8C, wherein fig. 8B and fig. 8C are schematic diagrams of the electrical connection relationship of the LED filament according to different embodiments of the present invention. Referring to fig. 8B, in the present embodiment, the anode P1 of the LED filament 100 is electrically connected to the first output terminal (or called positive output terminal) of the power module 518, and the first cathode N1 and the second cathode N2 of the LED filament 100 are electrically connected/short-circuited together and are commonly electrically connected to the second output terminal (or called negative output terminal) of the power module 518. As shown in fig. 8A, in the electrical connection relationship of fig. 8B, the LED segments 402 and 404 can be regarded as being connected in parallel to the output terminal of the power module 518, and thus both the LED segments 402 and 404 are driven by the driving voltage V1 between the first output terminal and the second output terminal. Under the condition that the number and configuration of the chips included in the LED segments 402 and 404 are the same or similar, the driving current provided by the power module 518 is uniformly distributed to each of the LED segments 402 and 404, so that the LED segments 402 and 404 exhibit substantially uniform brightness and/or color temperature.
Referring to fig. 8C, in the present embodiment, the anode P1 of the LED filament 100 is electrically connected to the first output terminal (or called positive output terminal) of the power module 518, the first cathode N1 of the LED filament 100 is electrically connected to the second output terminal (or called first negative output terminal) of the power module 518, and the second cathode N1 of the LED filament 100 is electrically connected to the third output terminal (or called second negative output terminal) of the power module 518, wherein a driving voltage V1 output is formed between the first output terminal and the second output terminal of the power module 518, and another driving voltage V2 output is formed between the first output terminal and the third output terminal of the power module 518. In the electrical connection relationship of fig. 8C, as seen in fig. 8A, the LED segment 402 is electrically connected between the first output terminal and the second output terminal, and the LED segment 404 is electrically connected between the first output terminal and the third output terminal, so that the LED segments 402 and 404 are considered to be driven by the driving voltages V1 and V2, respectively. With this configuration, the driving current provided by the power module 518 to the LED segment 402/404 can be independently controlled by modulating the output driving voltages V1 and V2, so that the LED segments 402 and 404 can have corresponding brightness and/or color temperature, respectively. In other words, under the configuration of fig. 8C, the power supply module 518 can be designed and controlled to implement the step dimming function on a single LED filament.
In some embodiments, the second output terminal and the third output terminal of the power module 518 may be connected together through a resistor, and one of the second output terminal and the third output terminal is electrically connected/shorted to a ground terminal. By this configuration, the negative output terminals with different levels can be formed, thereby generating the driving voltages V1 and V2 with different levels. In some embodiments, the second output terminal and the third output terminal may also be respectively controlled by a circuit, and the present invention is not limited to the above embodiments.
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 (10)
1. An LED filament, comprising:
an LED segment comprising at least two LED chips, the LED chips comprising GaN and a substrate;
the conductor section is electrically connected with two adjacent LED sections;
the light conversion layer comprises a top layer and a base layer, the top layer is coated on at least two sides of the LED chip, solid crystal glue is arranged between the base layer and the LED chip, light emitted by the LED chip passes through an interface A, an interface C, an interface D and an interface F, the interface A is an interface between the GaN and the top layer in the LED chip, the interface C is an interface between the substrate and the solid crystal glue in the LED chip, the interface D is an interface between the solid crystal glue and the base layer, the interface F is an interface between the base layer and the top layer, the refractive indexes of two adjacent substances of any interface are n1 and n2 respectively, and the absolute value of the difference value between n1 and n2 is smaller than 1.
2. The LED filament of claim 1 wherein the absolute value of the difference between n1 and n2 is less than 0.2.
3. The LED filament of claim 1 wherein the absolute value of the difference in the refractive indices of the two substances at either of the D, F interfaces is less than 0.5.
4. The LED filament of claim 3 wherein the absolute value of the difference in the refractive indices of the two substances at either of the D, F interfaces is less than 0.2.
5. The LED filament according to claim 1, wherein the conductor section includes a conductor, a maximum thickness of the LED chip in a radial direction of the LED filament is H, and a thickness of the conductor in the radial direction of the filament is 0.5H to 1.4H.
6. The LED filament according to claim 1, wherein the shortest distance between two of said LED chips respectively located in two adjacent LED segments is greater than the distance between two of said LED chips in any one of said LED segments.
7. The LED filament of claim 1, wherein the length of the conductor segment is greater than the distance between two adjacent LED chips in any of the LED segments.
8. An LED bulb lamp, characterized in that, the LED bulb lamp includes:
the lamp shell is filled with inert gas;
the lamp holder is connected with the lamp shell;
the at least one LED filament according to claims 1 to 5, wherein light emitted from the LED chip passes through an interface A, an interface B, an interface C, an interface D, an interface E and an interface F, the interface B is an interface between a top layer of the light conversion layer and the inert gas, the interface E is an interface between a base layer of the light conversion layer and the inert gas, and an absolute value of a difference between refractive indexes of two substances adjacent to any one interface is less than 1.
9. The LED bulb lamp of claim 8, wherein the absolute value of the difference in refractive index between two substances adjacent to any one of the B, E, D, F four interfaces is less than 0.5.
10. The LED bulb lamp of claim 9, wherein the absolute value of the difference in refractive index between two substances adjacent to any one of the B, E, D, F four interfaces is less than 0.2.
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| CN201811549205X | 2018-12-18 | ||
| CN201822198239.0U CN211952283U (en) | 2017-12-26 | 2018-12-26 | LED filament and LED bulb |
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| CN201822198239.0U Division CN211952283U (en) | 2017-12-26 | 2018-12-26 | LED filament and LED bulb |
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