Light emitting device
By using a wide-wave chip with a half-wave width greater than or equal to 20 nanometers, the fluorescent glue layer of fluoride red phosphor is stimulated, and the color drift problem caused by fluoride red phosphor is solved, achieving high light efficiency and low light efficiency The white light emission of color drift value significantly reduces the color coordinate offset.
Patent Information
- Application Number
- CN202411295470.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2024-12-24
AI Technical Summary
In the prior art, the luminescent products obtained by the red fluoride phosphor packaging have severe color drifts, resulting in increased production costs, and a variety of products need to be prepared to adapt to the slight differences in the use environment.
A wide-wave chip with a half-wave width greater than or equal to 20 nanometers is used to stimulate the fluorescence glue layer of fluoride red phosphor. Combined with yellow-green phosphor and nitride red phosphor, the color drift is reduced through the multi-crc turning point characteristics of the wide-wave chip. value.
The white light emission with high light efficiency and low color drift value is achieved, which significantly reduces the color drift caused by fluoride red phosphor, and especially the color coordinate offset at different temperatures is controlled within a small range.
Smart Images
Figure CN119181756A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of LED lighting, and in particular to a light-emitting device. Background Art
[0002] In the prior art, a blue light chip is usually used to excite phosphors to emit white light. Most phosphors are a combination of yellow-green phosphors and red phosphors. If you want to achieve higher light efficiency, you usually need to use fluoride red phosphors. Compared with the commonly used nitride red phosphors, fluoride red phosphors have the advantages of narrower half-wave width, higher excitation efficiency, and do not absorb the light emitted by yellow-green phosphors. However, due to the large color drift value of fluoride red phosphors, especially when it is used in high-rendering index products, the color drift is particularly obvious, which will result in the need to prepare a variety of different products for slight differences in customer usage environments (such as usage temperature), thereby significantly increasing production costs. Summary of the invention
[0003] In view of at least some of the problems and shortcomings in the prior art, an embodiment of the present invention discloses a light-emitting device to solve the problem of severe color drift of light-emitting products obtained by encapsulating fluoride red phosphor in the prior art.
[0004] On the one hand, an embodiment of the present invention provides a light-emitting device, for example, including: a wide-wave chip, the half-wave width of the wide-wave chip is greater than or equal to 20 nanometers; a fluorescent glue coated on the wide-wave chip, the fluorescent glue including fluoride red phosphor.
[0005] It can be seen from the above that the above technical features of the present invention can have one or more of the following beneficial effects: the light-emitting device provided in the embodiment of the present invention, by utilizing a wide-wave chip with a half-wave width greater than or equal to 20 nanometers to excite a fluorescent glue layer having a fluoride red phosphor, can enable the light-emitting device to emit white light with high luminous efficiency and low color drift value, thereby solving the problem of severe color drift caused by the fluoride red phosphor. BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 A structural schematic diagram of a light emitting device is provided for an embodiment of the present invention.
[0007] Figure 2 Another structural schematic diagram of a light emitting device is provided for an embodiment of the present invention.
[0008] Figure 3 A schematic diagram of the luminescence spectrum of the broadband chip provided by an embodiment of the present invention at different operating temperatures.
[0009] Figure 4 It is a schematic diagram of the structure of a COB packaged light-emitting device with multiple broadband chips.
[0010] Figure 5 Chromaticity diagram of a light-emitting device and an LED package made with conventional chips. DETAILED DESCRIPTION
[0011] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. In the specification, "on..." means being located above or below the target component, and does not mean that it must be located on the top based on gravity.
[0012] See also Figure 1 , a light-emitting device 10 provided in an embodiment of the present invention, for example, includes: a wide-wave chip 100 and a fluorescent glue 200, and the wide-wave chip 100 is, for example, coated in the fluorescent glue 200. Among them, the wide-wave chip 100 is, for example, a light-emitting diode chip that can emit a wide-band excitation light with a half-wave width (FWHM, Full Width at Half Maxima) greater than 20 nanometers, such as a GaN (gallium nitride)-based wide blue light chip. The fluorescent glue 200 includes fluoride red phosphor (such as KSF or KGF, etc.) in order to make the light-emitting device 10 have a higher light efficiency. In order to make the light-emitting device 10 emit white light, the fluorescent glue 200 may also include other phosphors, such as yellow-green phosphor (such as LuAG, GaYAG, YAG, Silicate, β-SiAlON, etc.), and in order to obtain a better color rendering index, the fluorescent glue 200 may also include nitride red phosphor (such as CASN, SCASN, etc.) or other phosphors.
[0013] Specifically, the broadband chip 100 used in the present invention is a light-emitting diode different from the traditional narrow-band chip. It may have a light-emitting structure as described in Chinese patents CN201910318051.1, CN201980045780.2 or CN202010442369.3, including at least three quantum well layers with different indium concentrations, which are stacked and grown in a certain order so that the broadband chip 100 can emit broadband blue light with only a single chip. Specifically, the luminous spectrum of the broadband chip 100 may have a half-wave width greater than 20 nanometers. Preferably, the present invention may select a broadband chip 100 with a half-wave width greater than 25 nanometers or greater than 30 nanometers.
[0014] The fluorescent powder and the silica gel are mixed to obtain the fluorescent glue 200. For example, all of the multiple fluorescent powders can be mixed together to form a single layer of fluorescent glue covering the broadband chip 100. For example, see Figure 1 , wherein the fluoride red phosphor is mixed with the yellow-green phosphor and other, for example, nitride red phosphor to form a fluorescent glue, and the fluorescent glue 200 is coated on the wide-wave chip 100 to form a single layer of fluorescent glue, and the single layer of fluorescent glue is obtained by one-time dispensing. Alternatively, multiple fluorescent powders can be mixed with silica gel as needed to form at least two fluorescent glues, which are layered and covered on the wide-wave chip, for example, see Figure 2 , wherein the fluoride red phosphor is made into a layer of fluorescent glue alone and is disposed on the wide-wave chip 100 to form a first fluorescent glue layer 210, and the yellow-green phosphor and other, for example, nitride red phosphor can be mixed to form another fluorescent glue and disposed on the side of the first fluorescent glue layer 210 away from the wide-wave chip 100 to form a second fluorescent glue layer 220. The first fluorescent glue layer 210 and the second fluorescent glue layer 220 are obtained, for example, by layered dispensing.
[0015] The light-emitting device 10 provided in the embodiment of the present invention can enable the light-emitting device to emit white light with high light efficiency and lower color drift value by using a wide-wave chip with a half-wave width greater than 20 nanometers to excite a fluorescent glue with a fluoride red phosphor. Specifically, please refer to Table 1, which is the data of the color coordinate change of different light-emitting devices at the use temperature of 25°C and 85°C. Among them, the control group is a white light-emitting device made of a traditional narrow-wave chip (a chip with a half-wave width less than 20 nanometers) and a single layer of fluorescent glue, and NO.1 to NO.10 are white light-emitting devices made of different wide-wave chips and the above-mentioned single layer of fluorescent glue. Table 1 shows the changes in the color coordinates measured by these white light-emitting devices at different use temperatures (such as 25°C and 85°C). It can be seen from the data in Table 1 that the use of a wide-wave chip with a fluoride red phosphor can reduce the color coordinate offset of the light-emitting device, that is, it can reduce color drift, compared with the traditional solution of using a narrow-wave chip with a fluoride red phosphor.
[0016] Table 1
[0017]
[0018] Furthermore, through a large number of test experiments, it is found that the wide-wavelength chip 100 with multiple peak turning points in the luminescence spectrum has a better effect of reducing color drift when used in conjunction with the fluoride red phosphor (the peak turning point of the present invention refers to the turning point of the spectrum graph or the point where the slope becomes significantly smaller). The wide-wavelength chip 100 selected in the present application has, for example, two or more peak turning points, preferably 2-5 peak turning points. Figure 3 This is a schematic diagram of the luminescence spectrum of a type of broadband chip with better color drift reduction effect at different operating temperatures measured by the present invention. Figure 3 As shown, the luminous spectrum of this type of wide-wavelength chip has at least one peak turning point in the range of 432.5 to 450 nanometers. The peak turning point with the shortest wavelength in this wavelength range is defined as the first peak turning point, and the second peak turning point adjacent to it on the long-wave side is the second peak turning point. In some embodiments, the wavelength value of the second peak turning point differs from the wavelength value of the first peak turning point by, for example, 8-20 nanometers; preferably, the wavelength value of the second peak turning point differs from the wavelength value of the first peak turning point by 10-14 nanometers. The use of this type of wide-wavelength chip can significantly reduce the large thermal color drift caused by the use of fluoride red phosphor.
[0019] Furthermore, this type of broadband chip was further screened and normalized based on the spectral intensity of the first wave peak turning point. It was found that a type of broadband chip with a spectral intensity ratio of the second wave peak turning point to the first wave peak turning point at an operating temperature of 85°C that is higher than that at 25°C can significantly reduce thermal color drift when used in conjunction with fluoride red phosphors, achieving the following: Figure 5 The color coordinates are shifted as shown. Figure 5 It can be clearly seen that, compared with the solution of using traditional narrow-wave chips with the same phosphor to make a white light emitting device 10, the use of the wide-wave chips selected in this embodiment can significantly reduce the thermal color drift caused by the use of fluoride red phosphors. For example, at an operating temperature of 85°C compared to an operating temperature of 25°C, the color coordinate offset distance can be achieved to be no more than 0.006, and in some better solutions it can even be achieved to be no more than 0.004.
[0020] Specifically Figure 3 For example, when the operating temperature is 25°C, the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point is about 60%; when the operating temperature changes to 85°C, the spectrum fluctuates, and the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point increases to 87%. Taking sample 2 as another example, when the operating temperature is 25°C, the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point is about 100%; when the operating temperature changes to 85°C, the spectrum fluctuates, and the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point increases to 133%. In some embodiments, preferably, at an operating temperature of 25°C, the luminous spectrum of the wide-wave chip 100, the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point is, for example, between 50% and 100%, and more preferably between 50% and 90%; when the operating temperature changes to 85°C, the spectral intensity ratio of the second wave peak turning point to the first wave peak turning point increases, for example, between 60% and 150%. Selecting a wideband chip that meets the above conditions can further reduce the large thermal color drift caused by the use of fluoride red phosphor.
[0021] from Figure 3 It can also be seen that when the operating temperature increases, the luminous spectrum of the wide-wave chip 100, in addition to the change in waveform, the entire spectrum will also undergo a certain degree of red shift. For the convenience of observation and screening, the aforementioned wide-wave chip 100 that can more effectively reduce the problem of thermal color drift of fluoride red phosphors usually has the following characteristics: the luminous spectrum at an operating temperature of 85°C is compared with the luminous spectrum at an operating temperature of 25°C. The ratio of the spectral intensity at 460nm to 440nm of the wide-wave chip 100 at 85°C is a first ratio, and the ratio of the spectral intensity at 460nm to 440nm of the wide-wave chip 100 at 25°C is a second ratio. The first ratio is greater than the second ratio, that is, the ratio of the spectral intensity at 460nm to 440nm of the wide-wave chip 100 at 85°C is greater than the ratio of the spectral intensity at 460nm to 440nm at 25°C.
[0022] Table 2 shows the optical data of a light emitting device 10 provided in this embodiment at different temperatures. This embodiment takes the light emitting device 10 with a color temperature of 3000K as an example. From the data in Table 2, it can be seen that the light emitting device 10 provided in this embodiment can reach a color rendering index of more than 90 at 25°C-105°C, that is, it has a high color rendering index. Secondly, it can be seen from Table 2 that the color coordinate offset distance can be achieved within 0.006 at 25°C-85°C, or even 25°C-105°C.
[0023] Table 2
[0024]
[0025]
[0026] The packaging form of the light emitting device 10 is, for example, COB packaging (Chips on Board), SMD packaging (Surface Mounted Devices) or filament packaging, etc., which is not limited in this application. However, it is particularly worth mentioning that for example Figure 4 For the COB package shown in the figure or other light-emitting devices 10 without a package bracket and insufficient deep operating space, the broadband chip of the present invention can realize one-time dispensing of multiple phosphors, save steps, reduce process difficulty, and also achieve a very good effect of reducing color drift. Figure 5 , to use Figure 4Taking the COB light-emitting device 10 with multiple wide-band chips 100 as an example, the center coordinate offset at 85°C is no more than 3 color tolerances at 25°C. Compared with COB light-emitting devices using conventional narrow-band chips, the color drift problem is significantly improved. Of course, for other light-emitting devices with better operating space, the following can also be used: Figure 2 The layered dispensing process shown achieves the effect of further reducing color drift.
[0027] In summary, the light-emitting device provided in the embodiment of the present invention, by utilizing a wide-wave chip with a half-wave width greater than or equal to 20 nanometers to excite a fluorescent glue layer having a fluoride red phosphor, can enable the light-emitting device to emit white light with a high rendering index and a low color drift value, thereby solving the problem of severe color drift caused by the use of fluoride red phosphors in high-efficiency light-emitting devices.
[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A light emitting device, characterized in that: include: A wide-wave chip, wherein the half-wave width of the wide-wave chip is greater than or equal to 20 nanometers; The fluorescent glue is coated on the broadband chip, and the fluorescent glue includes fluoride red fluorescent powder.
2. The light emitting device according to claim 1, characterized in that: The luminous spectrum of the broadband chip has multiple peak turning points, wherein the luminous spectrum of the broadband chip has at least one peak turning point in the range of 432.5 to 450 nanometers; the peak turning point with the shortest wavelength in the range of 432.5 to 450 nanometers is defined as the first peak turning point, and the second peak turning point adjacent to it on the long-wave side is defined as the second peak turning point.
3. The light emitting device according to claim 2, characterized in that: The wavelength value of the second wave crest turning point differs from the wavelength value of the first wave crest turning point by 8-20 nanometers.
4. The light emitting device according to claim 2, characterized in that: The intensity ratio of the second wave peak turning point to the first wave peak turning point at an operating temperature of 85°C is higher than the intensity ratio of the second wave peak turning point to the first wave peak turning point at an operating temperature of 25°C.
5. The light emitting device according to claim 4, characterized in that: At an operating temperature of 25°C, the intensity ratio of the second wave peak turning point to the first wave peak turning point is 50%-100%; at an operating temperature of 85°C, the intensity ratio of the second wave peak turning point to the first wave peak turning point is 60%-150%.
6. The light emitting device according to claim 1, characterized in that: The color coordinate shift distance between the light emitted by the light emitting device at an operating temperature of 85° C. and the light emitted by the light emitting device at an operating temperature of 25° C. is no greater than 0.
006.
7. The light emitting device according to claim 1, characterized in that: At an operating temperature of 85° C., the ratio of the spectral intensity of the broadband chip at a wavelength of 460 nanometers to the spectral intensity at a wavelength of 440 nanometers is a first ratio; at an operating temperature of 25° C., the ratio of the spectral intensity of the broadband chip at a wavelength of 460 nanometers to the spectral intensity at a wavelength of 440 nanometers is a second ratio; Wherein, the first ratio is greater than the second ratio.
8. The light emitting device according to claim 1, characterized in that: The number of the broadband chips is multiple, and the distance between the color coordinate center of the light emitted by the light emitting device at an operating temperature of 85° C. and the color coordinate center of the light emitted by the light emitting device at an operating temperature of 25° C. does not exceed 3 color tolerances.
9. The light emitting device according to any one of claims 1 to 8, characterized in that: The fluorescent glue also includes yellow-green fluorescent powder and / or nitride red fluorescent powder, and the fluorescent glue is coated on the broadband chip to form a single fluorescent glue layer.
10. The light emitting device according to any one of claims 1 to 8, characterized in that: The fluorescent glue includes a first fluorescent glue layer and a second fluorescent glue layer, the first fluorescent glue layer is arranged on the wide-wave chip, and the second fluorescent glue layer is arranged on a side of the first fluorescent glue layer away from the wide-wave chip, the first fluorescent glue layer includes the fluoride red phosphor, and the second fluorescent glue layer includes yellow-green phosphor and / or nitride red phosphor.