LED filament and bulb lamp using the same

Abstract

This application relates to the field of lighting and discloses an LED filament comprising an LED segment comprising at least two LED chips electrically connected to each other via a wire; a conductor segment comprising a conductor connecting two adjacent LED segments, the conductor being longer than the wire; an electrode electrically connected to the LED segment; and a light conversion layer covering at least the LED segment and a portion of the electrode, leaving a portion of the electrode exposed. The light conversion layer contains a phosphor composition having different peak wavelengths when excited by blue light. This application also discloses an LED bulb containing the aforementioned LED filament. This application features uniform light emission and excellent heat dissipation.

Description

Technical Field

[0001] The present application relates to the field of lighting, and in particular to an LED filament, and also to a bulb lamp using the LED filament. Background Art

[0002] LEDs, with their environmentally friendly, energy-saving, high-efficiency, and long lifespan, have gained widespread attention in recent years, gradually replacing traditional lighting fixtures. However, traditional LED light sources are directional, unlike traditional lamps that can illuminate at wide angles. Therefore, integrating LEDs into traditional lamps presents challenges depending on the type of fixture.

[0003] In recent years, an LED filament that allows LED light sources to emit light similar to traditional tungsten filament bulbs, achieving 360° full-angle illumination, has been gaining increasing attention in the industry. This type of LED filament is made by connecting multiple LED chips in series and fixing them on a narrow, elongated glass substrate. The entire glass substrate is then wrapped with silicone doped with phosphor and then electrically connected to complete the process. In addition, there is also a type of LED soft filament, which has a similar structure to the above-mentioned filament, but the glass substrate is partially replaced with a flexible substrate (hereinafter referred to as FPC), allowing the filament to have a certain degree of bendability. However, soft filaments made with FPC have disadvantages, such as the FPC's thermal expansion coefficient being different from the thermal expansion coefficient of the silicone coating the filament. Long-term use can cause the LED chip to shift or even debond; or the FPC is not conducive to flexible changes in process conditions.

[0004] The applicant has previously disclosed a flexible filament (e.g., some embodiments of Chinese Patent Publication No. CN106468405A). This flexible filament structure, devoid of a substrate, offers a flexible, wavelength-converting fluorescent package, replacing the traditional structure that requires mounting the chip on a substrate before applying phosphor and encapsulating it. However, some of these filament structures pose challenges to the stability of the metal bonding wires between the chips during bending. When the chips are densely arranged within the filament, connecting adjacent LED chips via metal bonding wires can lead to excessive stress concentration in specific locations within the filament when the filament is bent, potentially damaging or even breaking the metal bonding wires connecting the LED chips. Therefore, some embodiments still require further improvement in quality.

[0005] In the existing technology, most LED lamps use a combination of blue light LED chips and yellow phosphors to emit white light. However, the light in the red light region of the LED lamp's emission spectrum is weak, and the color rendering index is low, making it difficult to achieve a low color temperature. To improve the color rendering index, a certain amount of green phosphor and red phosphor are generally added. However, the relative conversion rate of red phosphor is low, which usually leads to a decrease in the overall luminous flux of the LED lamp, that is, a decrease in luminous efficiency.

[0006] Furthermore, LED filaments are typically incorporated into LED bulbs. To enhance their aesthetics and provide a more uniform and wide-ranging illumination, they are often bent into various curves. However, the LED chips within the filaments are relatively rigid, making them difficult to bend into the desired shape. Furthermore, the filaments are prone to cracking due to stress concentration during bending.

[0007] This application is a further optimization of the above application to further meet various process and product requirements. Summary of the Invention

[0008] It is particularly noted that the present disclosure may actually include one or more invention schemes that are currently claimed or not yet claimed, and in order to avoid confusion due to unnecessary distinctions between these inventions during the writing of the specification, the possible multiple invention schemes herein may be collectively referred to as "this application".

[0009] This summary describes a number of embodiments of the present application. However, the term "present application" is used only to describe certain embodiments disclosed in this specification (whether or not included in the claims), and is not a complete description of all possible embodiments. Certain embodiments of the various features or aspects described below as "present application" may be combined in various ways to form an LED bulb or a portion thereof.

[0010] The present application discloses an LED filament, comprising:

[0011] An LED segment, wherein the LED segment includes at least two LED chips, and the LED chips are electrically connected to each other via wires;

[0012] A conductor segment, comprising a conductor connecting two adjacent LED segments, wherein the length of the conductor is greater than the length of the wire;

[0013] an electrode electrically connected to the LED segment, and

[0014] A light conversion layer covers at least the LED segment and a portion of the electrode, leaving a portion of the electrode exposed. The light conversion layer includes a top layer and a base layer, respectively located on either side of the LED chip. The top layer includes a phosphor composition, the phosphor composition including a first phosphor having a wavelength peak of 490-500 nm and a full width at half maximum (FWHM) of 29-32 nm under blue light excitation; a second phosphor having a wavelength peak of 520-540 nm and a full width at half maximum (FWHM) of 110-115 nm under blue light excitation; a third phosphor having a wavelength peak of 660-672 nm and a full width at half maximum (FWHM) of 15-18 nm under blue light excitation; and a fourth phosphor having a wavelength peak of 600-612 nm and a full width at half maximum (FWHM) of 72-75 nm under blue light excitation. The weight percentages of the respective phosphors in the phosphor composition are as follows: 5.45-5.55% of the first phosphor, 70-88% of the second phosphor, 0.6-7% of the third phosphor, and the remainder being the fourth phosphor.

[0015] Preferably, the light conversion layer includes hollow glass microspheres, and the mass ratio of the glass microspheres to the phosphor composition is 1:5 to 15; the LED filament is supplied with no more than 8W of electrical energy, and when the LED filament is lit, at least 4lm of white light is emitted per millimeter of the LED filament length.

[0016] Preferably, the D50 of the first phosphor and the fourth phosphor is in the range of 16 to 20 μm.

[0017] Preferably, the top layer further comprises glue, and the weight ratio of the phosphor composition to the glue is 0.2-0.3:1.

[0018] Preferably, a blue light chip is included, wherein the peak wavelength of the blue light chip is 450-500 nm and the full width at half maximum (FWHM) is 15-18 nm.

[0019] The present application also discloses an LED bulb lamp, which comprises:

[0020] Lamp housing; the lamp housing is filled with gas, including nitrogen and oxygen, and the oxygen content is 1 to 10% of the volume of the lamp housing;

[0021] a lamp holder connected to the lamp housing;

[0022] a stem extending from the lamp holder into the lamp housing; and

[0023] A single LED filament is located in the lamp housing, and the LED bulb is located in a spatial coordinate system (X, Y, Z), wherein the Z axis is parallel to the core column, the diameter of the lamp head is R1, the maximum diameter of the lamp housing is R2, the maximum width of the LED filament in the Y-axis direction on the YZ plane or the maximum width in the X-axis direction on the XZ plane is R3, and R1<R3<R2.

[0024] Preferably, the gas contains impurities in an amount of 0.1 to 5% of the volume of the lamp housing.

[0025] Preferably, the LED filament has at least two first bending points and at least one second bending point when bent, the first bending points and the second bending points are spaced apart, and the height of any first bending point on the Z axis is greater than that of any second bending point.

[0026] Preferably, the distance between two adjacent first bending points on the Y-axis or the X-axis has a maximum value D1 and a minimum value D2, and the range of D2 is 0.5D1 to 0.9D1.

[0027] Preferably, the spectrum of the LED bulb has three peaks P1, P2 and P3 between 400nm and 800nm, the peak P1 is between 430nm and 480nm, the peak P2 is between 580nm and 620nm, and the peak P3 is between 680nm and 750nm.

[0028] Preferably, the intensity of the peak P1 is smaller than the intensity of the peak P2, and the intensity of the peak P2 is smaller than the intensity of the peak P3.

[0029] Preferably, the spectrum of the LED bulb has three peaks P1, P2 and P3 between 400nm and 800nm, the peak P1 is between 430nm and 480nm, the peak P2 is between 480nm and 530nm, and the peak P3 is between 630nm and 680nm.

[0030] The present application has the following technical effects or any combination thereof through the above technical scheme: (1) by adjusting the content of the first phosphor, the second phosphor, the third phosphor and the fourth phosphor in the phosphor composition, the LED filament can obtain better luminous performance; (2) by adjusting the ratio of the phosphor composition to the glue, the sedimentation of the phosphor can be greatly reduced, so that the light refraction law tends to be consistent; (3) the inflation gas contains a small amount of impurities, and the light emitted by the LED filament is emitted or refracted by the impurities, and the luminous angle is increased, which is beneficial to improving the luminous effect of the LED filament; (4) by designing the relationship between the diameter of the lamp head, the maximum diameter of the lamp shell and the maximum width of the LED filament in the Y-axis direction on the YZ plane or the maximum width in the X-axis direction on the XZ plane, the heat dissipation effect of the bulb lamp can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of an embodiment of an LED filament of the present application;

[0032] Figures 2A to 2DShown are a schematic diagram, a side view, another side view, and a top view of an LED bulb according to an embodiment of the present application;

[0033] Figure 3 FIG2 is a schematic diagram of the light spectrum of an LED bulb lamp according to an embodiment of the present application;

[0034] Figure 4 FIG2 is a schematic diagram of the light spectrum of an LED bulb lamp according to an embodiment of the present application;

[0035] Figure 5 FIG2 is a schematic diagram of the light emission spectrum of an LED bulb according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of an embodiment of the LED filament of the present application. Figure 1 As shown, the LED filament 400 comprises a light conversion layer 420; LED segments 402 and 404; electrodes 410 and 412; and a conductor segment 430 for electrically connecting adjacent LED segments 402 and 404. The LED segments 402 and 404 include at least two LED chips 442, which are electrically connected to each other via a conductor 440. In this embodiment, the conductor segment 430 includes a conductor 430a that connects the LED segments 402 and 404. The shortest distance between two LED chips 442 within adjacent LED segments 402 and 404 is greater than the distance between two adjacent LED chips within each LED segment 402 or 404, and the length of the conductor 440 is shorter than the length of the conductor 430a. This ensures that stress generated when the two LED segments are bent does not cause the conductor segment to break. The light conversion layer 420 is coated on at least two sides of the LED chips 442 and the electrodes 410 and 412. The light conversion layer 420 exposes a portion of the electrodes 410 and 412. The light conversion layer 420 may have at least a top layer 420a and a base layer 420b, which serve as the upper and lower layers of the filament, respectively. In this embodiment, the top layer 420a and the base layer 420b are located on either side of the LED chip 442 / electrodes 410 and 412, respectively. In one embodiment, if the filament is supplied with no more than 8W of electrical energy, the filament emits at least 4lm of white light per millimeter of filament length when it is lit. In one embodiment, at least two LED chips are included per millimeter of filament length, and in an ambient environment of 25°C, the temperature of the LED filament is no greater than the junction temperature when the LED filament is lit for 15,000 hours.

[0038] The phosphor composition as part of the top layer 420b includes a first phosphor, a second phosphor, a third phosphor, and a fourth phosphor. Under blue light excitation, the first phosphor has a peak wavelength of 490 to 500 nm and a full width at half maximum (FWHM) of 29 to 32 nm; under blue light excitation, the second phosphor has a peak wavelength of 520 to 540 nm and a full width at half maximum (FWHM) of 110 to 115 nm; under blue light excitation, the third phosphor has a peak wavelength of 520 to 540 nm and a full width at half maximum (FWHM) of 110 to 115 nm. The phosphor has a peak wavelength of 660-672 nm and a full width at half maximum (FWHM) of 15-18 nm. Under blue light excitation, the fourth phosphor has a peak wavelength of 600-612 nm and a full width at half maximum (FWHM) of 72-75 nm, or a peak wavelength of 620-628 nm and a full width at half maximum (FWHM) of 16-18 nm, or a peak wavelength of 640-650 nm and a full width at half maximum (FWHM) of 85-90 nm. The center particle size (D50) of any one of the first, second, third, and fourth phosphors is in the range of 15-20 μm. The D50 of the second and third phosphors is preferably in the range of 15-16 μm, and the D50 of the first and fourth phosphors is preferably in the range of 16-20 μm. When blue light excites phosphors, the thickness of the top layer, even with the same phosphor concentration, affects the phosphor's half-peak width. In this embodiment, the thickness of the top layer 420b is 80-100 μm. The weight percentages of the various phosphors in the phosphor composition are: 5.45-5.55% for the first phosphor, 70-88% for the second phosphor, 0.6-7% for the third phosphor, and the remainder for the fourth phosphor. The top layer, with a specific phosphor-to-glue ratio and phosphors of different peak wavelengths, was tested using a blue LED chip with a peak wavelength of 451 nm, a full width at half maximum (FWHM) of 16.3 nm, and a current of 30 mA. The measured optical performance is shown in Table 1.

[0039] Table 1

[0040]

[0041] From Nos. 1-4 in Table 1, it can be seen that the content of the third and fourth phosphors in the phosphor composition affects the luminous efficacy (Eff), average color rendering index (Ra), and saturated red (R9). From Nos. 1 and 2, it can be seen that increasing the content of the fourth phosphor with a peak wavelength of 670nm increases Eff, while Ra and R9 decrease. When replacing a phosphor with a peak wavelength of 652nm with a phosphor with a peak wavelength of 630nm, as can be seen from Nos. 3 and 4 in Table 1, increasing the content of the fourth phosphor with a peak wavelength of 670nm decreases Eff, while Ra and R9 increase. Therefore, when selecting fourth phosphors with different peak wavelengths, the amounts of the third and fourth phosphors can be adjusted to achieve optimal luminous performance.

[0042] The ratio of phosphor to glue

[0043] The same phosphor was selected and the ratio of the phosphor composition to the glue was adjusted as shown in Table 2. As can be seen from Table 2, different ratios of the phosphor composition to the glue resulted in different Eff, Ra, R9, and CCT. The higher the proportion of the phosphor composition to the glue, the lower the Eff, Ra, and CCT, while R9 showed a trend of decreasing and then increasing. Furthermore, when the phosphor composition is combined with glue (e.g., silica gel) as the top layer of an LED filament, during the production of the top layer, the phosphor composition has a greater specific gravity than the silica gel, which can cause significant sedimentation of the phosphor, resulting in a color temperature shift in the white light LED. The greater the proportion of the phosphor, the more phosphor sedimentation occurs, and the more severe the color temperature shift. Therefore, the weight ratio of the phosphor composition to the glue in the top layer is 0.2 to 0.3:1, preferably 0.25 to 0.3:1. In one embodiment, a certain amount of hollow glass microspheres can be added to the phosphor composition. As the phosphor settles, the glass microspheres float upward. This floating process reduces the backscattering / emission of light, offsetting the light scattering effect of the phosphor settling. This can mitigate color temperature shift. Furthermore, because the microspheres absorb little visible light, the addition of the glass microspheres has a minimal effect on the initial brightness of the white LED. The mass ratio of the glass microspheres to the phosphor composition is 1:5-15, and preferably the weight ratio is 1:10-15.

[0044] Table 2

[0045]

[0046] In one embodiment, an LED filament is provided. The LED filament is made of the phosphor composition described above and a blue light chip. The blue light chip has a peak wavelength of 450 to 500 nm and a half-peak width of 15 to 18 nm.

[0047] Please refer to Figure 2A and Figures 2B to 2D , Figure 2A FIG. 4 is a schematic diagram of an LED bulb 40h according to an embodiment of the present application. Figures 2B to 2D Shown are Figure 2A The side view, the other side view and the top view of the LED bulb lamp 40h. Figures 2A to 2DAs shown, the LED bulb includes a lamp housing 12, a lamp base 16 connected to the lamp housing 12, a stem 19 disposed within the lamp housing 12, and a single LED filament 100. The stem 19 includes a bottom portion and a top portion (also referred to as a vertical rod 19a) that are opposed to each other. The bottom portion is connected to the lamp base 16, and the top portion extends into the interior of the lamp housing 12. For example, the top portion may be located approximately at the center of the interior of the lamp housing 12. The LED filament 100 includes a filament body and two filament electrodes 110 and 112 located at opposite ends of the filament body. The filament body is the portion of the LED filament 100 excluding the filament electrodes 110 and 112.

[0048] During the manufacturing process of traditional bulbs, to prevent the tungsten filament from burning in air and causing oxidation and fracture, a glass structure with a flared stem is designed to fit over the opening of the glass bulb housing and be sintered and sealed. A vacuum pump is then connected through the port of the flared stem to replace the air inside the lamp housing with nitrogen, preventing the tungsten filament from burning and oxidizing. Finally, the port of the flared stem is sintered and sealed. The vacuum pump, through the stem, replaces the air inside the lamp housing with pure nitrogen or a combination of nitrogen and helium in an appropriate ratio, improving the thermal conductivity of the gas inside the lamp housing and removing any water mist lurking in the air. In one embodiment, the air can be replaced with a combination of nitrogen and oxygen or nitrogen and air in an appropriate ratio, with the oxygen or air content being 1-10% of the lamp housing volume, preferably 1-5%. When the base layer contains saturated hydrocarbons, during use of the LED bulb, the saturated hydrocarbons can be exposed to light, heat, stress, and other factors to generate free radicals. These free radicals or activated molecules combine with oxygen to form peroxide radicals. Filling the lamp housing with oxygen can improve the heat and light resistance of the base layer containing saturated hydrocarbons.

[0049] During the manufacturing process of an LED bulb, to increase the refractive index of the light emitted by the LED filament in the lamp housing 12, foreign matter, such as rosin, may be attached to the inner wall of the lamp housing 12. The average thickness of the foreign matter deposited per square centimeter of the inner wall area of ​​the lamp housing 12 is 0.01 to 2 mm, preferably 0.01 to 0.5 mm. In one embodiment, the foreign matter content per square centimeter of the inner wall area of ​​the lamp housing 12 accounts for 1% to 30%, preferably 1% to 10%, of the total foreign matter content of the inner wall of the lamp housing 12. This foreign matter content can be adjusted, for example, by vacuum drying the lamp housing. In another embodiment, a portion of impurities may be left in the gas filling the lamp housing 12, with the impurity content in the gas filling being 0.1% to 20%, preferably 0.1% to 5%, of the volume of the lamp housing 12. This impurity content can be adjusted, for example, by vacuum drying the lamp housing. Because the gas filling contains a small amount of impurities, the light emitted by the LED filament is reflected or refracted by the impurities, increasing the emission angle, thereby improving the luminous effect of the LED filament.

[0050] The LED bulb is located in a spatial coordinate system (X, Y, Z), wherein the Z axis is parallel to the core column 19. When the LED filament 100 is bent, it has at least two first bending points and at least one second bending point. The first bending points and the second bending points are spaced apart. The height of any first bending point on the Z axis is greater than that of any second bending point. In one embodiment, the spacing between two adjacent first bending points on the Y axis or the X axis is equal, and the appearance of the LED filament is neat and beautiful. In one embodiment, the spacing between two adjacent first bending points on the Y axis or the X axis has a maximum value D1 and a minimum value D2, and the range of D2 is 0.5D1 to 0.9D1. The luminous flux distribution on each plane is relatively consistent. Assume that the diameter of the lamp head 16 is R1 (see Figure 2B ), the maximum diameter of the lamp housing 12 or the maximum horizontal spacing of the lamp housing 12 in the YZ plane is R2 (see Figure 2B ), the maximum width of the LED filament 100 in the Y-axis direction on the YZ plane (see Figure 2B ) or the maximum width in the X-axis direction on the XZ plane is R3 (see Figure 2C ), R3 is between R1 and R2, i.e., R1 < R3 < R2. When the LED filament is bent, the spacing between adjacent first and / or second bending points in the Z-axis direction is wide, which helps improve the heat dissipation of the LED filament. During the LED bulb manufacturing process, the LED filament 100 can be first placed in the interior space of the lamp housing 12 in a folded manner, and then manually or mechanically stretched within the lamp housing 12 so that the maximum length of the filament 100 in the XZ plane satisfies the above relationship.

[0051] like Figures 2A to 2D As shown, in this embodiment, the LED filament 100 has one conductor segment 130, while there are two LED segments 102 and 104. Each adjacent LED segment 102 and 104 is connected by a conductor segment 130. The LED filament 100 bends in an arc at its highest point, i.e., the LED segments 102 and 104 each bend in an arc at their highest point, and the conductor segment also bends in an arc at its lowest point. The LED filament 100 can be defined as a segment following each bent conductor segment 130, with each LED segment 102 and 104 forming a corresponding segment.

[0052] Furthermore, because the LED filament 100 utilizes a flexible substrate, preferably a silicone-modified polyimide resin composition, the LED segments 102 and 104 themselves also possess a certain degree of bendability. In this embodiment, the two LED segments 102 are each bent into an inverted U-shape, with the conductor segment 130 positioned between them. The degree of bendability of the conductor segment 130 is equal to or greater than that of the LED segments 102. Specifically, the two LED segments 102 are bent into an inverted U-shape at the filament's highest point, each with a bend radius R1. The conductor segment 130 is bent at the filament's lowest point, each with a bend radius R2, where R1 is greater than R2. This configuration of the conductor segment 130 enables the LED filament 100 to bend with a small turning radius within a limited space. In one embodiment, the bend points of the LED segments 102 and 104 are at the same height in the Z direction. The height of the pole 19a corresponds to the height of the conductor segments 130. For example, the lowest point of the conductor segments 130 can be connected to the top of the pole 19a to prevent deformation of the overall shape of the LED filament 100. In various embodiments, the conductor segments 130 can be connected through holes in the top of the pole 19a or by being glued to the top of the pole 19a, but are not limited to these. In one embodiment, the conductor segments 130 and the pole 19a can be connected using a wire, for example, a wire extending from the top of the pole 19a to connect the conductor segments 130.

[0053] like Figure 2B As shown, in this 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 downward to extend to the conductor segment 130 connecting the two LED segments 102. Figure 2C As shown, in this embodiment, the profile of the LED filament 100 in the XZ plane is similar to a V shape, that is, the two LED segments 102 extend obliquely upward and outward, bend at the highest point, and then extend obliquely downward and inward to the conductor segment 130. Figure 2D As shown in FIG. 1 , in this embodiment, the profile of the LED filament 100 in the XY plane has an S shape. Figure 2B and Figure 2D As shown, in this embodiment, the conductor segment 130 is located between the electrodes 110 and 112. Figure 2D As shown, in this embodiment, on the XY plane, the bending point of the LED segment 102 , the bending point of the LED segment 104 , and the electrodes 110 , 112 are substantially located on a circle with the conductor segment 130 as the center.

[0054] Please refer to Figure 3 , Figure 3This is a schematic diagram of the light spectrum of an LED bulb according to an embodiment of the present application. In this embodiment, the LED bulb can be any of the LED bulbs disclosed in the previous embodiments, and any single LED filament disclosed in the previous embodiments is provided in the LED bulb. The light emitted by the LED bulb can be measured by a spectrum measuring instrument, and the following can be obtained: Figure 3 As shown in the spectrum diagram. From this spectrum diagram, it can be seen that the spectrum of the LED bulb is mainly distributed between the wavelength of 400nm and 800nm, and there are three peaks P1, P2, and P3 at three locations in this range. Peak P1 is approximately between the wavelength of 430nm and 480nm, peak P2 is approximately between the wavelength of 580nm and 620nm, and peak P3 is approximately between the wavelength of 680nm and 750nm. In terms of intensity, the intensity of peak P1 is less than the intensity of peak P2, and the intensity of peak P2 is less than the intensity of peak P3. Figure 3 As shown in FIG, such a spectrum distribution is close to the spectrum distribution of a traditional incandescent filament lamp and is also close to the spectrum distribution of natural light. In one embodiment, the light spectrum diagram of a single LED filament is as follows: Figure 4 As shown in the spectrum diagram, the LED bulb's spectrum is primarily distributed between 400nm and 800nm, with three peaks, P1, P2, and P3, appearing within this range. Peak P1 is approximately between 430nm and 480nm, peak P2 is approximately between 480nm and 530nm, and peak P3 is approximately between 630nm and 680nm. This spectral distribution is similar to that of traditional incandescent filament lamps and also to that of natural sunlight.

[0055] Please refer to Figure 5 , Figure 5 The light spectrum of the LED bulb lamp of an embodiment of the present application is shown in the figure. As can be seen from the figure, the spectrum distribution of the LED bulb lamp has a similar wavelength between 400nm and 800nm. Figure 4 The three peaks P1', P2', and P3' shown differ in that P1' has a greater intensity than P1, and P3' has a greater half-wave width than P3. This LED bulb has an average color rendering index Ra (R1-R8) greater than 95, a saturated red (R9) greater than or equal to 90, and an LED filament luminous efficacy (Eff) greater than or equal to 100 lm / w.

[0056] The "single LED filament" or "single LED filament" referred to in this application refers to a structure formed by connecting the aforementioned conductor segments and LED segments together, or consisting solely of LED segments, having an identical and continuous light conversion layer (including an identical and continuously formed top or bottom layer), and having only two conductive electrodes at both ends electrically connected to the conductive support of the bulb. A structure that meets the above structural description is referred to in this application as a single LED filament structure.

[0057] The present application has been disclosed above with preferred embodiments, but those skilled in the art should understand that the embodiments are only used to describe some of the embodiments of the present application and should not be interpreted as limiting. It should be noted that any changes and replacements equivalent to the embodiments or reasonable combinations between the embodiments (especially Figure 1 2 ) should be included within the scope supported by this application specification. Therefore, the scope of protection of this application shall be based on the scope defined by the attached claims.

Claims

1. An LED filament, characterized in that: The LED filament comprises: An LED segment, wherein the LED segment includes at least two LED chips, and the LED chips are electrically connected to each other via wires; A conductor segment, comprising a conductor connecting two adjacent LED segments, wherein the length of the conductor is greater than the length of the wire; an electrode electrically connected to the LED segment, and A light conversion layer covers at least the LED segment and a portion of the electrode, leaving a portion of the electrode exposed. The light conversion layer includes a top layer and a base layer, respectively located on either side of the LED chip. The top layer includes a phosphor composition, the phosphor composition including a first phosphor having a peak wavelength of 490-500 nm and a full width at half maximum (FWHM) of 29-32 nm under blue light excitation, a second phosphor having a peak wavelength of 520-540 nm and a full width at half maximum (FWHM) of 110-115 nm under blue light excitation, a third phosphor having a peak wavelength of 660-672 nm and a full width at half maximum (FWHM) of 15-18 nm under blue light excitation, and a fourth phosphor having a peak wavelength of 600-612 nm and a full width at half maximum (FWHM) of 72-75 nm under blue light excitation. The weight percentages of the respective phosphors in the phosphor composition are as follows: 5.45-5.55% of the first phosphor, 70-88% of the second phosphor, 0.6-7% of the third phosphor, and the remainder of the fourth phosphor.

2. The LED filament according to claim 1, characterized in that The light conversion layer includes hollow glass microspheres, and the mass ratio of the glass microspheres to the phosphor composition is 1:5 to 15; the LED filament is supplied with no more than 8W of electrical energy, and when the LED filament is lit, at least 4lm of white light is emitted per millimeter of the LED filament length.

3. The LED filament according to claim 1, characterized in that The D50 of the first phosphor and the fourth phosphor is in the range of 16 to 20 μm.

4. The LED filament according to claim 1, characterized in that The top layer further comprises glue, and the weight ratio of the phosphor composition to the glue is 0.2-0.3:

1.

5. The LED filament according to claim 1, characterized in that The blue light chip comprises a blue light chip, wherein the peak wavelength of the blue light chip is 450-500nm and the full width at half maximum (FWHM) is 15-18nm.

6. An LED bulb, characterized in that: The LED bulb lamp comprises: Lamp housing; the lamp housing is filled with gas, the gas includes nitrogen and oxygen, and the oxygen content is 1 to 10% of the volume of the lamp housing; a lamp holder connected to the lamp housing; a stem extending from the lamp holder into the lamp housing; and The LED filament described in any one of claims 1 to 5 is located in the lamp housing, and the LED bulb is located in a spatial coordinate system (X, Y, Z), wherein the Z axis is parallel to the core column, the diameter of the lamp head is R1, the maximum diameter of the lamp housing is R2, and the maximum width of the LED filament in the Y-axis direction on the YZ plane or the maximum width in the X-axis direction on the XZ plane is R3, wherein R1<R3<R2.

7. The LED bulb according to claim 6, characterized in that: The gas contains impurities whose content is 0.1-5% of the volume of the lamp shell.

8. The LED bulb according to claim 6, characterized in that: When the LED filament is bent, it has at least two first bending points and at least one second bending point. The first bending points and the second bending points are spaced apart. The height of any first bending point on the Z axis is greater than that of the second bending point.

9. The LED bulb according to claim 8, characterized in that: The distance between two adjacent first bending points on the Y-axis or the X-axis has a maximum value D1 and a minimum value D2, wherein D2 ranges from 0.5D1 to 0.9D1.

10. The LED bulb according to claim 8, characterized in that: The spectrum of the LED bulb has three peaks P1, P2 and P3 between 400nm and 800nm, the peak P1 is between 430nm and 480nm, the peak P2 is between 580nm and 620nm, and the peak P3 is between 680nm and 750nm.

11. The LED bulb according to claim 8, characterized in that: The intensity of the peak P1 is smaller than the intensity of the peak P2 , and the intensity of the peak P2 is smaller than the intensity of the peak P3 .

12. The LED bulb according to claim 8, characterized in that: The spectrum of the LED bulb has three peaks P1, P2 and P3 between 400nm and 800nm, the peak P1 is between 430nm and 480nm, the peak P2 is between 480nm and 530nm, and the peak P3 is between 630nm and 680nm.

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