A phosphor composition with high light efficiency and COB flexible light strip

Abstract

The present invention provides a phosphor composition with high light efficiency and a COB soft light strip. The phosphor composition contains 40wt% to 66wt% of fluoride red phosphor. The structural formula of the fluoride red phosphor is K2Si (1‑x) F6:Mn x , wherein x = 0.045 to 0.070. Compared with existing conventional phosphors, the composition of the present invention containing fluoride red phosphor has higher lighting efficiency performance. Within the color temperature range of 2700K-6500K and a color rendering index of 90Ra, the lighting efficiency is improved by more than 8%, improving the lighting efficiency of COB lamps while reducing the number or power of chips, greatly saving packaging costs. The surface of the fluorescent adhesive layer of the COB soft light strip of the present invention is covered with a waterproof film formed by thermal curing of heptadecafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane, which reduces the power consumption and heat generation of the lamp, and at the same time reduces the thermal quenching of the YAG yellow-green powder caused by the heat generation of the lamp and the thermal aging caused by high temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and in particular to a phosphor composition with high light efficiency and a COB flexible light strip. Background Art

[0002] As a linear lighting product, COB light strips feature linear illumination and uniform, consistent light emission, making them suitable replacements for some conventional low-voltage, or LED, light strips. Conventional light strips utilize an SMT (Surface Mount Technology) process to solder the LEDs to the circuit board. Different levels of waterproofing are achieved through external glue dripping, injection molding, silicone sleeves, and PU sleeves. However, due to market maturity, a wide variety of products, and transparent pricing, competition is currently fierce. COB soft light strips, on the other hand, feature improved manufacturing processes, employing a flip-chip process to directly package the LED chips onto the circuit board. Different luminous colors are then achieved through silicone coating. The light strips utilize high-density LEDs, mixed with a phosphor colloid for linear dispensing. The resulting linear luminous surface creates a highly consistent color.

[0003] The phosphors used in existing COB soft light strips are typically YAG yellow-green powder plus nitride red phosphor, which is combined with blue light chips to form various color temperature schemes from 2700K to 6500K. However, the luminous efficiency of COB soft light strips with this scheme is low at 90 display schemes, and the phosphor cost is also high. In addition, most of the fluorescent glue in the COB soft light strip packaging scheme is exposed outside the aluminum substrate, making the phosphor in the COB soft light strip packaging scheme more susceptible to aging in high temperature and high humidity working environments than traditional surface mount packaging schemes. Summary of the Invention

[0004] The present invention aims to provide a phosphor composition with high luminous efficiency and a COB flexible light strip, so as to solve the problems of high packaging cost, low luminous efficiency and poor aging resistance of phosphors in existing COB flexible light strips.

[0005] Based on the above purpose, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a phosphor composition with high light efficiency, wherein the phosphor composition contains 40 wt% to 66 wt% of a fluoride red phosphor; the structural formula of the fluoride red phosphor is A2(MF6):Mn 4+ , its D 50 =3.0~44.0μm, D 10 ≥1.0μm, D 90 ≤85.0μm, particle size distribution coefficient P=(D 90 -D 10 ) / D 50 ≤1.0;

[0007] Wherein, A includes any one of Li, Na, K, Rb, Cs, and NH4, and M includes any one of Ge, Si, Sn, Ti, Zr, and Sc.

[0008] Preferably, the structural formula of the fluoride red phosphor is K2Si (1-x) F6:Mn x , where x = 0.045 ~ 0.070.

[0009] Compared with existing phosphors, K2Si (1-x) F6:Mn x The fluoride red phosphor of the present invention has a high luminous quantum efficiency and has a narrow-band emission of 631 nm. It also avoids the problem of self-absorption of yellow-green light by conventional LED nitride red phosphors, thereby greatly improving the luminous efficiency of white light LED solutions. The fluoride red phosphor of the present invention is applied to backlight phosphor solutions. Due to the narrow-band emission characteristics of the fluoride red phosphor, the fluoride red phosphor can provide a better display color gamut.

[0010] Preferably, the particle size of the fluoride red phosphor is 24-28 μm.

[0011] The experiment found that the particle size of the fluoride red phosphor in the phosphor has a certain influence on the lighting efficiency of the COB soft light strip. When the particle size is between 16 and 44 μm, as the particle size increases, within the color temperature range of 2700K to 6500K, the lighting efficiency of the COB soft light strip shows a trend of first increasing and then decreasing. When the particle size of the fluoride red phosphor is 24 to 28 μm, the COB soft light strip has the best lighting efficiency.

[0012] Preferably, when the color rendering index Ra is 90, the phosphor composition includes 43.3 wt% to 65.1 wt% of fluoride red phosphor, 34.9 wt% to 48.4 wt% of yellow-green phosphor, 0 wt% to 8.3 wt% of nitride red phosphor, and 0 wt% to 1.8 wt% of oxynitride cyan phosphor.

[0013] Preferably, the excitation wavelength of the yellow-green phosphor is 450-460 nm, and the emission wavelength is 525 nm; the excitation wavelength of the nitride red phosphor is 450-460 nm, and the emission wavelength is 615 nm; the excitation wavelength of the nitrogen oxide cyan phosphor is 450-460 nm, and the emission wavelength is 495 nm.

[0014] Depending on the color temperature, the components of the phosphor composition are appropriately adjusted within the above range. When the color rendering index (Ra) is 90, within the color temperature range of 2700K to 6500K, the luminous efficacy of the phosphor composition containing the fluoride red phosphor of the present invention is improved by 8% to 20% compared to conventional phosphor compositions.

[0015] Preferably, when the color rendering index Ra is 90 and the color temperature is 2700K, the phosphor composition includes 43.3 wt % of fluoride red phosphor, 48.4 wt % of yellow-green phosphor, and 8.3 wt % of nitride red phosphor.

[0016] Preferably, when the color rendering index Ra is 90 and the color temperature is 3000K, the phosphor composition includes 44 wt % of fluoride red phosphor, 48.4 wt % of yellow-green phosphor, and 7.6 wt % of nitride red phosphor.

[0017] Preferably, when the color rendering index Ra is 90 and the color temperature is 4000K, the phosphor composition includes 55.8 wt % of fluoride red phosphor, 41.8 wt % of yellow-green phosphor, and 2.4 wt % of nitride red phosphor.

[0018] Preferably, when the color rendering index Ra is 90 and the color temperature is 5000K, the phosphor composition includes 65.1 wt % of fluoride red phosphor and 34.9 wt % of yellow-green phosphor.

[0019] Preferably, when the color rendering index Ra is 90 and the color temperature is 6500K, the phosphor composition includes 51.7 wt % of fluoride red phosphor, 46.5 wt % of yellow-green phosphor, and 1.8 wt % of nitrogen oxide cyan phosphor.

[0020] In a second aspect, the present invention provides applications of the phosphor composition in COB flexible light strips, LED lights, and backlight devices.

[0021] In a third aspect, the present invention provides a COB flexible light strip with high lighting efficiency, comprising a COB substrate, the COB substrate being covered with an LED chip and a fluorescent adhesive layer, the surface of the fluorescent adhesive layer being covered with a waterproof film; the fluorescent adhesive layer material contains the above-mentioned phosphor composition.

[0022] Preferably, the waterproof membrane material is heptadecafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane.

[0023] The present invention covers the substrate and fluorescent adhesive layer of the COB soft light strip with a dense waterproof film to prevent the fluorescent adhesive from being in a high-humidity environment. Compared with the existing COB soft light strip without a waterproof film, the present invention improves the aging resistance of the COB soft light strip.

[0024] In a fourth aspect, the present invention provides a method for preparing the above-mentioned high-light-efficiency COB flexible light strip, comprising the following steps:

[0025] S1: Apply fluorescent glue on the surface of the COB substrate of the COB flexible light strip, dry it to solidify the fluorescent glue, and form a fluorescent glue layer;

[0026] S2: spray heptafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane on the surface of the COB substrate and the cured fluorescent adhesive layer, and dry at 100°C to form a waterproof film.

[0027] Preferably, the mixed viscosity of the fluorescent glue is 25000-35000 mPa.S (25° C., 10 rpm), and the hardness is Shore A30-40.

[0028] Within this hardness range, fluorescent glue can effectively provide mechanical protection and stress relief. By using fluorescent glue and waterproof film, the aging performance of phosphor in COB light strips is improved, slowing down the aging of COB light strips.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Compared with conventional phosphors, the phosphor composition containing fluoride red phosphor of the present invention has higher lamp light efficiency performance. Within the color temperature range of 2700K-6500K and with a color rendering index of 90Ra, the lamp light efficiency is improved by at least 8%. The phosphor composition containing fluoride red phosphor of the present invention is used in the fluorescent adhesive layer of COB flexible light strips, which helps improve the COB lamp light efficiency while reducing the number or power of chips, greatly saving packaging costs, and reducing lamp power consumption and heat generation problems. It also reduces the thermal quenching of YAG yellow-green powder caused by lamp heat generation and the thermal aging caused by high temperature.

[0031] (2) Since fluoride red phosphor has poor resistance to high temperature and high humidity, its performance in lighting packaging is poor. In addition, a large amount of fluoride red phosphor is used in the LED packaging process. The present invention reduces the amount of fluoride red phosphor used by using ultra-small particle size fluoride red phosphor while ensuring high luminous efficiency. Experiments have found that when the particle size of the fluoride red phosphor is 24 to 28 μm, it has the best luminous efficiency.

[0032] (3) The present invention sprays heptafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane on the surface of the COB substrate and the cured fluorescent adhesive layer to form a waterproof film, thereby improving the aging resistance of the COB soft light strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the COB flexible light strip of the present invention.

[0034] In the figure: 1. LED chip; 2. COB substrate; 3. Resistor element; 4. Fluorescent adhesive layer; 5. Electrode connector; 6. Waterproof film. DETAILED DESCRIPTION

[0035] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] A phosphor composition with high light efficiency, the phosphor composition contains 40wt% to 66wt% of fluoride red phosphor; the structural formula of the fluoride red phosphor is A2(MF6):Mn 4+ , its D 50 =3.0~44.0μm, D 10 ≥1.0μm, D 90 ≤85.0μm, particle size distribution coefficient P=(D 90 -D 10 ) / D 50 ≤1.0; the particle size of the fluoride red phosphor is preferably 24 to 28 μm.

[0038] Wherein, A includes any one of Li, Na, K, Rb, Cs, Sc, and NH4, and M includes any one of Ge, Si, Sn, Ti, and Zr.

[0039] Preferably, the structural formula of the fluoride red phosphor is K2Si (1-x) F6:Mn x , where x = 0.045 ~ 0.070.

[0040] When the color rendering index Ra is 90, the phosphor composition includes 43.3wt% to 65.1wt% of fluoride red phosphor, 34.9wt% to 48.4wt% of yellow-green phosphor, 0wt% to 8.3wt% of nitride red phosphor, and 0wt% to 1.8wt% of nitride cyan phosphor. The yellow-green phosphor has an excitation wavelength of 450 to 460nm and an emission wavelength of 525nm; the red nitride phosphor has an excitation wavelength of 450 to 460nm and an emission wavelength of 615nm; and the cyan nitride phosphor has an excitation wavelength of 450 to 460nm and an emission wavelength of 495nm. According to the different color temperatures, the selection of each component in the phosphor composition is reasonably adjusted within the above range, as shown in Table 1. In Table 1, KS630 represents the fluoride red phosphor of the present invention, YG535 represents the aluminate yellow-green phosphor, R615 represents the nitride red phosphor, H552 represents the aluminate yellow phosphor, and NO490 represents the nitrogen oxide cyan phosphor.

[0041] Table 1 Composition ratio of phosphor compositions corresponding to different color temperatures when the color rendering index is Ra 90

[0042] phosphor KS630 YG535 R615 NO490 2700K 43.3wt% 48.4wt% 8.3wt% -- 3000K 44wt% 48.4wt% 7.6wt% -- 4000K 55.8wt% 41.8wt% 2.4wt% -- 5000K 65.1wt% 34.9wt% -- -- 6500K 51.7wt% 46.5wt% -- 1.8wt%

[0043] Taking the phosphor compositions in Table 1 as an example and the component ratios of conventional phosphor compositions as a control, the luminous efficacy of the phosphor compositions of the present application at different color temperatures was analyzed. The results are shown in Table 2, wherein KSF represents the phosphor composition of the present invention, the phosphor compositions corresponding to different color temperatures are shown in Table 1, R640 represents a nitride red phosphor, H542 represents an aluminate yellow phosphor, and YG535 represents an aluminate yellow-green phosphor.

[0044] Table 2 Comparison of the luminous efficacy of the phosphor composition of the present invention and conventional phosphor compositions

[0045]

[0046] From the luminous efficiency comparison results in Table 2, it can be seen that compared with the existing conventional phosphor compositions, the phosphor composition containing the fluoride red phosphor of the present invention has better luminous efficiency. When the color temperature is 2700K, the luminous efficiency of the phosphor composition of the present invention is improved by 20.38% compared with the conventional phosphor composition; when the color temperature is 3000K, the luminous efficiency of the phosphor composition of the present invention is improved by 17.80% compared with the conventional phosphor composition; when the color temperature is 4000K, the luminous efficiency of the phosphor composition of the present invention is improved by 12.11% compared with the conventional phosphor composition; when the color temperature is 5000K, the luminous efficiency of the phosphor composition of the present invention is improved by 8.55% compared with the conventional phosphor composition; when the color temperature is 6500K, the luminous efficiency of the phosphor composition of the present invention is improved by 14.18% compared with the conventional phosphor composition.

[0047] The particle size of the fluoride red phosphor in the phosphor composition was used as a single factor variable to analyze the effect of the particle size on the luminous efficiency. The results are shown in Table 3.

[0048] Table 3 Luminous efficacy values ​​(Lm / w) corresponding to the particle size of fluoride red phosphors of different particle sizes

[0049]

[0050] From the results in Table 3, it can be seen that the particle size of the fluoride red phosphor in the phosphor has a certain influence on the lighting efficiency of the COB soft light strip. When the particle size is between 16 and 44 μm, as the particle size increases, the lighting efficiency of the COB soft light strip shows a trend of first increasing and then decreasing within the color temperature range of 2700K to 6500K. When the particle size of the fluoride red phosphor is 24 to 28 μm, the COB soft light strip has the best lighting efficiency.

[0051] Example 2

[0052] A COB soft light strip with high light efficiency, such as Figure 1The COB substrate 2 is shown as including a COB substrate 2, on which an LED chip 1, a resistor element 3, and a fluorescent adhesive layer 4 are covered. An electrode connector 5 is provided at the end of the COB substrate 2; the surface of the fluorescent adhesive layer 4 is covered with a waterproof film 6; the material of the fluorescent adhesive layer 4 contains the fluorescent powder composition containing fluoride red phosphor described in Example 1 (as shown in Table 1), and the particle size of the fluoride red phosphor in the fluorescent powder composition is 24 to 28 μm.

[0053] LED chip 1 uses a wafer with a wavelength of 452.5 to 455 nm, with a width of 150 to 500 μm and a length of 500 to 1000 μm. The waterproof membrane 6 is made of heptadecafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane. A dense waterproof membrane is applied to the COB substrate and fluorescent adhesive layer of the COB flexible light strip to protect the fluorescent adhesive from high humidity. Compared to existing COB flexible light strips without a waterproof membrane, this application improves the aging resistance of the COB flexible light strip.

[0054] The method for preparing the high-light-efficiency COB flexible light strip comprises the following steps:

[0055] S1: Apply fluorescent glue to the surface of the COB substrate 2 of the COB flexible light strip and dry until the glue solidifies to form a fluorescent glue layer. The mixed viscosity of the fluorescent glue is 25,000 to 35,000 mPa.s (25°C, 10 rpm) and the hardness is Shore A 30 to 40. Within this hardness range, the fluorescent glue can effectively provide mechanical protection and stress relief.

[0056] S2: spraying heptafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane on the surface of the COB substrate 2 and the fluorescent adhesive layer, and drying at 100° C. to form a waterproof film.

[0057] By using fluorescent glue and waterproof film, the aging performance of phosphor in COB light strips is improved, slowing down the aging of COB light strips.

[0058] The lighting effects of the COB soft light strip containing a waterproof film and the COB soft light strip without a waterproof film of the present invention were tested respectively, and the results are shown in Table 4, where "conventional COB" means no waterproof film, and the remaining parts not mentioned have the same structure and composition. It can be seen from the results in Table 4 that the present application adopts the method of spraying heptafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane on the surface of the COB substrate and the cured fluorescent glue to form a waterproof film, which improves the aging resistance of the COB soft light strip.

[0059] Table 4 Comparison of the lighting effects of the COB flexible light strips in this application and the COB flexible light strips without waterproof film

[0060]

[0061] In summary, the phosphor composition containing fluoride red phosphor of the present invention has higher lamp light efficiency performance. Within the color temperature range of 2700K to 6500K and the color rendering index of 90Ra, the lamp light efficiency is improved by at least 8%, up to 20.38%. The present invention adopts the phosphor composition containing fluoride red phosphor to improve the COB lamp light efficiency, while reducing the number or power of chips, greatly saving packaging costs, and reducing the power consumption and heat generation problems of the lamp, reducing the thermal quenching of YAG yellow-green powder caused by the heat generation of the lamp and the thermal aging problems caused by high temperature.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A COB flexible light strip with high light efficiency, comprising a COB substrate covered with LED chips and a fluorescent adhesive layer, characterized in that: The surface of the fluorescent adhesive layer is covered with a waterproof film; the waterproof film material is heptadecafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane; the fluorescent adhesive layer material contains a phosphor composition; the phosphor composition contains 40wt% to 66wt% of fluoride red phosphor; the structural formula of the fluoride red phosphor is A2(MF6):Mn 4+ , its D 50 =24~28μm, D 10 ≥1.0μm, D 90 ≤85.0μm, particle size distribution coefficient P=(D 90 -D 10 ) / D 50 ≤1.0; Wherein, A includes any one of Li, Na, K, Rb, Cs, and NH4, and M includes any one of Ge, Si, Sn, Ti, Zr, and Sc.

2. The COB flexible light strip according to claim 1, characterized in that: When the color rendering index Ra is 90, the phosphor composition includes 43.3 wt% to 65.1 wt% of fluoride red phosphor, 34.9 wt% to 48.4 wt% of yellow-green phosphor, 0 wt% to 8.3 wt% of nitride red phosphor, and 0 wt% to 1.8 wt% of oxynitride cyan phosphor.

3. The COB flexible light strip according to claim 2, characterized in that: The yellow-green phosphor has an excitation wavelength of 450-460 nm and an emission wavelength of 525 nm; the nitride red phosphor has an excitation wavelength of 450-460 nm and an emission wavelength of 615 nm; the nitrogen oxide cyan phosphor has an excitation wavelength of 450-460 nm and an emission wavelength of 495 nm.

4. A method for preparing the high-light-efficiency COB flexible light strip according to claim 1, characterized in that: The steps include: S1: Apply fluorescent glue on the surface of the COB substrate of the COB flexible light strip, dry it to solidify the fluorescent glue, and form a fluorescent glue layer; S2: spray heptafluorodecyltriethoxysilane or γ-glycidyloxypropyltrimethoxysilane on the surface of the COB substrate and the cured fluorescent adhesive layer, and dry at 100°C to form a waterproof film.

5. The method according to claim 4, characterized in that: The mixed viscosity of the fluorescent glue is 25000-35000 mPa.S (25° C., 10 rpm), and the hardness is Shore A 30-40.

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