Light-emitting device and method for manufacturing light-emitting device

Abstract

The embodiment of the invention provides a light-emitting device and a manufacturing method of the light-emitting device. The light emitting device includes: a substrate; the light-emitting chip is arranged on the substrate; the first fluorescent glue layer only covers the upper surface of the light-emitting chip, and the first fluorescent glue layer comprises first fluorescent powder; the precipitation layer covers the first fluorescent glue layer, the side face of the light-emitting chip and the substrate, and the precipitation layer comprises second fluorescent powder different from the first fluorescent powder; the clear glue layer is arranged on one side, far away from the substrate, of the precipitation layer; the thickness ratio of the first fluorescent glue layer to the part, located on the upper surface of the light-emitting chip, of the precipitation layer is smaller than 2; the CRI of the light-emitting device is larger than or equal to 90. The light-emitting device provided by the embodiment of the invention can improve the excitation efficiency of the first fluorescent powder and improve the heat dissipation efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lighting technology, and in particular to a light emitting device and a manufacturing method of a light emitting device. BACKGROUND

[0002] Currently, LED products packaged with fluoride phosphor (such as KSF, KGF) are gradually becoming popular, mainly because the spectral efficiency of fluoride phosphor is greatly improved compared with traditional red phosphor such as nitride.

[0003] However, the efficiency of fluoride phosphor excited by blue light is low, and the packaging of white light LED products usually includes a variety of phosphors with different structures (for example, selected from garnet, silicate, sialon powder, nitride, fluoride, etc.), and the densities of these phosphors are different. When using traditional glue mixing, dispensing and sedimentation processes, various phosphors are mixed together and sink at the same time, and the phosphor with greater specific gravity is more likely to fall to the bottom layer and be close to the light emitting surface of the chip. Finally, the proportion of fluoride phosphor close to the light emitting surface of the chip is less than the proportion of fluoride phosphor far from the light emitting surface of the chip. Further affect the conversion effect of fluoride phosphor excited, and then affect the light efficiency of white light LED product. SUMMARY

[0004] Therefore, in order to overcome at least part of the defects and deficiencies in the prior art, the embodiments of the present application provide a light emitting device and a manufacturing method of a light emitting device.

[0005] Specifically, in one aspect, the light emitting device provided by the embodiments of the present application comprises: a substrate; a light emitting chip disposed on the substrate; a first phosphor glue layer covering only the upper surface of the light emitting chip, the first phosphor glue layer containing a first phosphor; a sedimentation layer covering the first phosphor glue layer, the side surface of the light emitting chip and the substrate, the sedimentation layer containing a second phosphor different from the first phosphor; a glue removal layer disposed on the side of the sedimentation layer away from the substrate; the thickness ratio of the first phosphor glue layer to the sedimentation layer on the upper surface of the light emitting chip is less than 2; and the CRI of the light emitting device is greater than or equal to 90.

[0006] In another aspect, the present application also provides a manufacturing method of a light emitting device, comprising: disposing a light emitting chip on a substrate; forming a first fluorescent glue layer on the upper surface of the light emitting chip by a powder spraying process or a dispensing process, wherein the first fluorescent glue mixture comprises fluoride fluorescent powder, silica gel and diluent; forming a second fluorescent glue layer on the first fluorescent glue layer and the substrate, wherein the second fluorescent glue layer comprises a precipitate layer and a clean glue layer, the precipitate layer covers the first fluorescent glue layer, the side surface of the light emitting chip and the substrate, and the clean glue layer is located on the side of the precipitate layer away from the substrate; the thickness ratio of the first fluorescent glue layer to the precipitate layer located on the upper surface of the light emitting chip is less than 2; and the color rendering index of the light emitting device is greater than 90.

[0007] As can be seen from the above, the light emitting device provided by the present application covers the upper surface of the light emitting chip with the first fluorescent glue layer, covers the first fluorescent glue layer, the side surface of the light emitting chip and the substrate with the second fluorescent glue layer, and the first fluorescent glue layer comprises the first fluorescent powder, so that the first fluorescent powder is close to the light emitting chip, the excitation efficiency of the first fluorescent powder is improved, and the heat dissipation efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0009] Figure 1 A flowchart of a manufacturing method of a light emitting device provided by the present application.

[0010] Figure 2 A structure diagram of a light emitting device provided by the present application.

[0011] Figure 3 A structure diagram of another light emitting device provided by the present application.

[0012] Figure 4 A structure diagram of still another light emitting device provided by the present application.

[0013] Figure 5 A structure diagram of yet another light emitting device provided by the present application.

[0014] Figure 6 A structure diagram of yet another light emitting device provided by the present application.

[0015] Figure 7A structural schematic diagram of another light emitting device provided by an embodiment of the present application.

[0016] Main element labels: 10, light emitting device; 11, main light emitting area; 12, peripheral area; 100, substrate; 200, light emitting chip; 300, first fluorescent glue layer; 400, second fluorescent glue layer; 410, precipitate layer; 420, glue removing layer. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments described in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the protection scope of the present application.

[0018] It should be noted that all directionality indications (such as up, down, left, right, front, back, top, bottom) in the embodiments of the present application are only used to explain the relative position relationship, movement condition and the like between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0019] In the embodiments of the present application, the description such as “first”, “second” and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as “first”, “second” can explicitly or implicitly include at least one of the features.

[0020] Referring to Figure 1 and Figure 2 , the embodiments of the present application provide a light emitting device 10 and a manufacturing method of a light emitting device, Figure 2 The light emitting device 10 shown can be manufactured, for example, by Figure 1 the manufacturing method of a light emitting device shown.

[0021] As Figure 1 shown, the manufacturing method of the light emitting device 10 can for example include the following steps: S10, disposing a light emitting chip on a substrate; S20, forming a first fluorescent glue layer on the upper surface of the light emitting chip by a powder spraying process or a glue dispensing process, the first fluorescent glue mixture including a fluoride fluorescent powder, a silica gel and a diluent; S30, forming a second fluorescent glue layer on the first fluorescent glue layer.

[0022] Specifically, a substrate 100 is provided, and the upper surface of the substrate 100 can for example include a die-bonding area, and a light emitting chip 200 is fixed to the die-bonding area on the substrate 100. In the present embodiment, the light emitting device 10 can be an SMD package (Surface Mounted Device), a COB package (Chip on Board), or a filament package. The light emitting chip 200 can for example be one or more. In a COB package, a filament package, or the like, in which a plurality of (typically more than 3) light emitting chips 200 are simultaneously provided on a substrate 100, the manufacturing method of the present embodiment has more obvious advantages. The first phosphor glue layer 300 is formed on the upper surface (i.e. the main light emitting surface) of the light emitting chip 200. For example, a first phosphor glue mixture is first formed by mixing fluoride phosphor, silica gel, and a diluent, and the diluent can for example be siloxane or toluene. Then, the first phosphor glue mixture is applied to the upper surface of the light emitting chip 200 by a powder spraying process or a dispensing process, and the like. Since the diluent has the characteristic of being volatile, after volatilization, the first phosphor glue layer 300 including fluoride phosphor and silica gel is formed on the upper surface of the light emitting chip.

[0023] By adding a diluent to the mixture of fluoride phosphor and silica gel, the viscosity of the first phosphor glue mixture can be reduced, and the first phosphor glue mixture can be more quickly and uniformly formed on the main light emitting surface of the light emitting chip 200 by a powder spraying process, or uniformly formed on the main light emitting surface of the light emitting chip 200 in a dispensing and quick leveling manner, the amount of silica gel is reduced, and the fluoride phosphor is uniformly distributed in the silica gel, thereby improving the excitation conversion effect of the fluoride phosphor and improving the light emitting efficiency of the light emitting device 10. In the present embodiment, the first phosphor glue layer 300 can be formed only on the main light emitting surface (i.e. the upper surface) of the light emitting chip 200, or can be simultaneously formed on the substrate 100 around the light emitting chip 200 and / or coated on the side surface of the light emitting chip 200. Specific embodiments are described below in different embodiments.

[0024] The second fluorescent adhesive layer 400 is formed on the first fluorescent adhesive layer 300, for example, by a method similar to that used to form the first fluorescent adhesive layer 300, or for example, by a conventional dispensing process. Specifically, in one embodiment of this example, a second fluorescent adhesive mixture can be formed by first mixing yellow-green phosphor with other phosphors such as nitride red phosphor, silica gel, and a diluent, and then applying the second fluorescent adhesive mixture onto the first fluorescent adhesive layer 300 using a powder spraying or dispensing process, allowing the diluent to evaporate before forming the second fluorescent adhesive layer 400. In another embodiment of this example, a third fluorescent adhesive mixture can be formed by first mixing yellow-green phosphor with other phosphors such as nitride red phosphor and silica gel, and then applying the third fluorescent adhesive mixture onto the first fluorescent adhesive layer 300 using a conventional dispensing process to form the second fluorescent adhesive layer 400. Of course, this embodiment is not limited to these methods.

[0025] like Figure 2 As shown, the light-emitting device 10 provided in this embodiment of the invention may include, for example, a substrate 100, a light-emitting chip 200, a first phosphor layer 300, and a second phosphor layer 400. The substrate 100 may be, for example, a metal substrate, a ceramic substrate, a glass substrate, a composite substrate, etc. The light-emitting chip 200 may be, for example, a blue light-emitting chip, and the light-emitting chip 200 is disposed on the substrate 100. The first phosphor layer 300 covers the light-emitting chip 200 and includes fluoride phosphor and silicone, with the fluoride phosphor uniformly distributed within the silicone. The fluoride phosphor is a manganese-activated fluoride series red phosphor; commonly used fluoride phosphors include K2SiF6:Mn. 4+ (KSF), K2TiF6:Mn 4+ (KTF), K2GeF6:Mn 4+ (KGF), etc. A second fluorescent adhesive layer 400 covers the first fluorescent adhesive layer 300. The second fluorescent adhesive layer 400 may include, for example, yellow-green phosphors and nitride red phosphors, or other phosphors, which are not particularly limited in this invention. The light-emitting device 10 provided in this embodiment covers the light-emitting chip 200 with a first fluorescent adhesive layer 300, and a second fluorescent adhesive layer 400 covers the first fluorescent adhesive layer 300. The first fluorescent adhesive layer 300 includes fluoride phosphors and silicone. By sequentially layering the first fluorescent adhesive layer 300 containing fluoride phosphors and the second fluorescent adhesive layer 400 containing other phosphors onto the light-emitting chip 200, the fluoride phosphors, which have relatively low excitation efficiency, are brought closer to the light-emitting chip 200, and particularly closer to the main light-emitting surface of the light-emitting chip 200, thus improving the excitation effect of the fluoride phosphors and further improving the light extraction efficiency of the light-emitting device 10.

[0026] Preferably, the first fluorescent adhesive layer 300 of the present invention is as follows: Figure 1The method shown involves mixing fluoride phosphor with silica gel and a diluent, then forming the mixture onto the light-emitting chip 200 using methods such as powder spraying or dispensing. The first phosphor layer 300 formed in this way, after the diluent evaporates, exhibits specific structural characteristics. This allows the first phosphor layer 300 to more easily and uniformly cover the main light-emitting surface of the light-emitting chip 200, achieving better excitation-conversion effects and light extraction efficiency with less phosphor. Specifically, as... Figure 2 As shown, the space above and on the upper surface of the light-emitting chip 200 is defined as the main light-emitting region 11, and the region outside the main light-emitting region 11 is defined as the peripheral region 12. The first phosphor layer 300 covers the main light-emitting region 11 and the peripheral region 12. In some embodiments of this example, the first phosphor layer 300 may, for example, cover the upper surface and side surface of the light-emitting chip 200, and also cover the upper surface of the substrate 100. In some embodiments, using the upper surface of the substrate 100 as a reference plane, the height H1 of the first phosphor layer 300 on the upper surface of the main light-emitting region 11 is greater than the height H2 of the first phosphor layer 300 on the upper surface of the peripheral region 12. That is, the height H1 between the upper surface of the first phosphor layer 300 on the main light-emitting region 11 and the upper surface of the substrate 100 is greater than the height H2 between the upper surface of the first phosphor layer 300 on the peripheral region 12 and the upper surface of the substrate 100. In other words, the first phosphor layer 300 will exhibit a height difference on its upper surface in a cross-sectional view of the light-emitting device 10 perpendicular to the upper surface of the light-emitting chip 200. In some more preferred embodiments, the height H2 of the first phosphor layer 300 on the upper surface of the peripheral region 12 is even lower than the height H3 of the upper surface of the light-emitting chip 200. That is, the height of the upper surface of the first phosphor layer 300 on the peripheral region 12 relative to the upper surface of the substrate 100 is lower than the height of the upper surface of the light-emitting chip 200 relative to the upper surface of the substrate 100. From another perspective, in this embodiment, the second fluorescent adhesive layer 400 is formed on the first fluorescent adhesive layer 300 and is also formed simultaneously in the main light-emitting region 11 and the peripheral region 12. The height of the second fluorescent adhesive layer 400 on the lower surface of the peripheral region 12 is lower than its height on the lower surface of the main light-emitting region 11. In some more preferred embodiments, the height of the second fluorescent adhesive layer 400 on the lower surface of the peripheral region 12 is even lower than the height H3 of the upper surface of the light-emitting chip 200.

[0027] In the embodiments of the present application, 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. However, it is particularly worth mentioning that for the light emitting device 10 in COB packaging or other multi-chip (more than three) packaging (i.e., with a larger packaging area), the first fluorescent glue layer 300 formed by mixing the fluoride fluorescent powder, the silica gel and the diluent on the light emitting chip 200 in the present application by means of powder spraying or dispensing, etc. overcomes the problem that the traditional layered dispensing process is difficult to implement in a larger packaging area, realizes the effect that the fluoride fluorescent powder more conveniently and uniformly covers the main light emitting surface of the light emitting chip 200, and improves the light efficiency and light uniformity of such products.

[0028] In addition, in the first fluorescent glue layer 300 of the light emitting device 10 provided in some embodiments of the present application, the fluoride fluorescent powder is uniformly distributed and not layered; in addition, the mass percentage (i.e., the ratio of the mass of the fluoride fluorescent powder to the total mass of the fluoride fluorescent powder and the silica gel in the first fluorescent glue layer 300) can be greater than 60%, or even greater than 70%. However, in the traditional dispensing scheme, once the mass percentage of the fluoride fluorescent glue exceeds 50%, there is a problem of poor flowability and difficulty in uniform dispensing. Thus, while realizing high excitation conversion effect and high light efficiency, the present application can reduce the amount of fluoride fluorescent glue. Through such a setting, for example, when the silica gel content in the first fluorescent glue layer 300 is high, the heat dissipation of the light emitting device 10 can be affected. However, it should be noted that the mass percentage of the fluoride fluorescent powder in the first fluorescent glue layer 300 of the light emitting device 10 of the present application can be more than 60%, and is not limited to all embodiments in which the mass percentage is more than 60%. The specific selection will be adjusted according to the light emission requirements of the light emitting device 10, the collocation of other fluorescent powders, etc.

[0029] In the embodiments of the present application, the ratio of the fluoride fluorescent powder and the silica gel in the first fluorescent glue layer 300 can be, for example, between 1:9 and 9:1, i.e., the mass percentage of the fluoride fluorescent powder in the first fluorescent glue layer 300 is between 10% and 90%. Preferably, the mass percentage of the fluoride fluorescent powder in the first fluorescent glue layer 300 is between 60% and 90%. Through such a setting, for example, when the silica gel content in the first fluorescent glue layer 300 is high, the heat dissipation can be affected. In some embodiments of the present application, as shown in FIG. 1, when the amount of the first fluorescent glue layer 300 is large, or the ratio of the fluoride fluorescent powder and the silica gel is low, the upper surface of the first fluorescent glue layer 300 will present a relatively smooth curved surface with a small height difference. Figure 3 Figure 2 ​As shown, when the amount of the first fluorescent glue layer 300 is small, or the ratio of the fluoride fluorescent powder and the silica gel is high, the upper surface of the first fluorescent glue layer 300 can present a greater high-low difference; for example Figure 4 As shown, when the amount of the first fluorescent glue layer 300 is small, or the ratio of the fluoride fluorescent powder and the silica gel is high, the upper surface of the first fluorescent glue layer 300 can present a greater high-low difference; for example

[0030] Please refer to Figure 5 , Figure 5 is another embodiment of the present application, the luminescent device 10 provided by the embodiment includes a substrate 100, a luminescent chip 200, and a first fluorescent glue layer 300. The selection and setting of the substrate 100, the luminescent chip 200, and the first fluorescent glue layer 300 are the same as those of the embodiment shown in Figure 2 , and thus will not be described herein. The main difference between the embodiment and the embodiment shown in Figure 2 is that the second fluorescent glue layer 400 provided by the embodiment is arranged on the first fluorescent glue layer 300 in a layered manner. In the preparation method, the steps of natural precipitation and centrifugal / semi-centrifugal precipitation can be added on the basis of the method of forming the second fluorescent glue layer 400. Most of the other fluorescent powders in the second fluorescent glue layer 400 in the embodiment are deposited on the surface of the first fluorescent glue layer 300, so that the second fluorescent glue layer 400 presents a layered structure, i.e., the second fluorescent glue layer 400 can include, for example, a deposition layer 410 close to the first fluorescent glue layer 300 and a glue cleaning layer 420 away from the first fluorescent glue layer 300, i.e., the glue cleaning layer 420 is located on the side of the deposition layer 410 away from the first fluorescent glue layer 300 and away from the luminescent chip 200. It should be noted that the glue cleaning layer 420 does not completely contain fluorescent glue, but the content / concentration of the fluorescent powder visible to the naked eye in the glue cleaning layer 420 is less than that in the deposition layer 410.

[0031] In another aspect, in a cross-sectional view of the light emitting device 10 of the present embodiment perpendicular to the main light emitting surface of the light emitting chip 200, the phosphor glue can be shown as a three-layer structure, including a first phosphor glue layer 300, a precipitate layer 410, and a clean glue layer 420, the precipitate layer 410 is located between the first phosphor glue layer 300 and the clean glue layer 420, and the clean glue layer 420 is located on the side of the precipitate layer 410 away from the light emitting chip 200. The second phosphor glue layer 400 is formed on the first phosphor glue layer 300, and is also formed in the main light emitting area 11 and the peripheral area 12 at the same time. The height of the lower surface of the second phosphor glue layer 400 in the peripheral area 12 is lower than the height of the lower surface of the second phosphor glue layer 400 in the main light emitting area 11, that is, the height between the lower surface of the second phosphor glue layer 400 on the peripheral area 12 and the upper surface of the substrate 100 is less than the height between the lower surface of the second phosphor glue layer 400 on the main light emitting area 11 and the upper surface of the substrate 100, so that the phosphor in the second phosphor glue layer 400 can be more concentrated close to the substrate 100, which helps the heat of the phosphor in the second phosphor glue layer 400 to be conducted downward through the substrate 100, and improves the thermal stability of the light emitting device 10. In some embodiments of the present embodiment, in order to ensure better heat dissipation effect, a precipitation step is added when forming the second phosphor glue layer 400, so that the second phosphor glue layer 400 is better leveled, and the phosphor contained therein also tends to precipitate towards the substrate 100, and fills the gap between the main light emitting area 11 and the peripheral area 12 of the first phosphor glue layer 300, so that the interface between the first phosphor glue layer 300 and the precipitate layer 410 presents a relatively larger undulating gap, while the interface between the precipitate layer 410 and the clean glue layer 420 presents a smaller undulation. In another aspect, the thickness W3 of the precipitate layer 410 of the second phosphor glue layer 400 in the peripheral area 12 is greater than the thickness W2 of the precipitate layer 410 in the main light emitting area 11. For the CRI90 series of light emitting devices 10, in order to ensure the light emitting effect (light color, indication, etc.), it is necessary to adjust the appropriate ratio of fluoride phosphor to other phosphor, and in order to better the thermal stability (such as improving the heat dissipation effect), it is necessary to control the amount of the first phosphor glue layer 300. The current experiment finds that when the ratio of the thickness W1 of the first phosphor glue layer 300 located in the main light emitting area 11 to the thickness W2 of the precipitate layer 410 is less than 2, the above-mentioned better effect can be uniformly achieved. Preferably, the thickness W1 of the first phosphor glue layer 300 located in the main light emitting area 11 is less than the thickness W2 of the precipitate layer 410.

[0032] Please refer to Figure 6 , Figure 6 is another embodiment of the present application. The selection and arrangement of the substrate 100, the light emitting chip 200, and the second phosphor glue layer 400 of the light emitting device 10 of the present embodiment are the same as those of the embodiment shown in Figure 2 , which will not be described here. The light emitting device 10 of the present embodiment is the same as that of Figure 2The main difference of the light emitting device 10 shown in the figure is that the first phosphor glue layer 300 only covers the main light emitting area 11 and is not arranged in the peripheral area 12, so when the second phosphor glue layer 400 is formed on the first phosphor glue layer 300, the main light emitting area 11 is located on the side of the first phosphor glue layer 300 away from the light emitting chip 200, and the peripheral area 12 is directly located on the substrate 100, but in this case, it also meets the condition that the height H1 of the upper surface of the first phosphor glue layer 300 in the main light emitting area 11 is greater than the height H2 of the upper surface of the first phosphor glue layer 300 in the peripheral area 12 (in this embodiment, the thickness is equal to 0); or more accurately, it also meets the condition that the height of the lower surface of the second phosphor glue layer 400 in the peripheral area 12 is lower than the height of the lower surface of the second phosphor glue layer 400 in the main light emitting area 11.

[0033] Referring again to Figure 7 , Figure 7 is another embodiment of the present application, and the light emitting device 10 of the embodiment includes a substrate 100, a light emitting chip 200, and the selection and arrangement of the first phosphor glue layer 300, which are the same as those of the embodiment shown in Figure 6 . Therefore, the description will not be repeated here. The main difference between the light emitting device 10 of the embodiment and the light emitting device 10 shown in Figure 6 is that the second phosphor glue layer 400 of the embodiment is arranged on the first phosphor glue layer 300 in a layered manner. In terms of method, the steps of natural precipitation and centrifugal / semi-centrifugal precipitation can be added to the method of forming the second phosphor glue layer 400 described above. In the embodiment, most of the other phosphor powders in the second phosphor glue layer 400 are deposited on the surface of the first phosphor glue layer 300 and the surface of the substrate 100, so that the second phosphor glue layer 400 exhibits a layered structure, i.e., the second phosphor glue layer 400 may, for example, include a precipitation layer 410 and a glue cleaning layer 420 located on the precipitation layer 410. The main difference between the second phosphor glue layer 400 of the embodiment and the second phosphor glue layer 400 provided by the embodiment shown in Figure 5 is that the precipitation layer 410 is arranged on the substrate 100 in the peripheral area 12, but the height of the lower surface of the second phosphor glue layer 400 in the peripheral area 12 is still lower than the height of the lower surface of the second phosphor glue layer 400 in the main light emitting area 11, and the thickness W3 of the precipitation layer 410 of the second phosphor glue layer 400 in the peripheral area 12 is greater than the thickness W2 of the precipitation layer 410 in the main light emitting area 11, so that the phosphor powders in the second phosphor glue layer 400 can be more concentratedly close to the substrate 100, which helps the heat of the phosphor powders in the second phosphor glue layer 400 to be conducted downward through the substrate 100, thereby improving the thermal stability of the light emitting device 10.

[0034] In addition, it can be understood that the technical solutions of the various embodiments can be combined and used as desired without conflict in technical features, contradiction in structure, or violation of the purpose of the application, as long as the various embodiments are only exemplary descriptions of the present application.

[0035] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A light emitting device, characterized by, The application relates to a light emitting device, comprising: a substrate; a light emitting chip arranged on the substrate; a first fluorescent glue layer only covering an upper surface of the light emitting chip, the first fluorescent glue layer containing first fluorescent powder; a precipitate layer covering the first fluorescent glue layer, side surfaces of the light emitting chip and the substrate, the precipitate layer containing second fluorescent powder different from the first fluorescent powder; a clean glue layer arranged on a side of the precipitate layer away from the substrate; a thickness ratio of the first fluorescent glue layer to the precipitate layer on a part of the upper surface of the light emitting chip is less than 2; and a CRI of the light emitting device is greater than or equal to 90.

2. The light emitting device of claim 1, wherein The thickness of the first fluorescent glue layer is less than the thickness of the precipitate layer on the part of the upper surface of the light emitting chip.

3. The light emitting device of claim 1, wherein The first fluorescent powder is fluoride fluorescent powder, and the mass of the fluoride fluorescent powder accounts for 60% or more of the mass of the first fluorescent glue layer.

4. The light emitting device of claim 1, wherein The light emitting device comprises a main light emitting area and a peripheral area, the main light emitting area is a space above the upper surface of the light emitting chip, and the peripheral area is an area other than the main light emitting area; a height of the precipitate layer on the upper surface of the peripheral area is lower than a height of the precipitate layer on the upper surface of the main light emitting area.

5. The light emitting device of claim 4, wherein The thickness of the precipitate layer in the peripheral area is greater than the thickness of the precipitate layer in the main light emitting area.

6. The light emitting device of claim 1, wherein The clean glue layer contains the second fluorescent powder, and a content of the second fluorescent powder in the clean glue layer is less than a content of the second fluorescent powder in the precipitate layer.

7. A method for manufacturing a light-emitting device, comprising the steps of: The application relates to a light emitting device, comprising: arranging a light emitting chip on a substrate; forming a first fluorescent glue layer on an upper surface of the light emitting chip by a powder spraying process or a glue dispensing process, the first fluorescent glue layer being formed by a first fluorescent glue mixture, the first fluorescent glue mixture comprising fluoride fluorescent powder, silica gel and a diluent; forming a second fluorescent glue layer on the first fluorescent glue layer and the substrate, the second fluorescent glue layer comprising a precipitate layer and a clean glue layer, the precipitate layer covering the first fluorescent glue layer, side surfaces of the light emitting chip and the substrate, and the clean glue layer being arranged on a side of the precipitate layer away from the substrate; a thickness ratio of the first fluorescent glue layer to the precipitate layer on a part of the upper surface of the light emitting chip is less than 2; and a color rendering index of the light emitting device is greater than 90.

8. The method for manufacturing a light emitting device according to claim 7, wherein The thickness of the first fluorescent glue layer is less than the thickness of the precipitate layer on the part of the upper surface of the light emitting chip.

9. The method for manufacturing a light emitting device according to claim 7, wherein The step of forming the first fluorescent glue layer by the powder spraying process or the glue dispensing process comprises volatilization of the diluent, the first fluorescent glue layer contains fluoride fluorescent powder and silica gel, and the concentration of the fluoride fluorescent powder in the first fluorescent glue layer is greater than 60%.

10. The method for manufacturing a light emitting device according to claim 7, wherein The second fluorescent glue layer contains second fluorescent powder different from the fluoride fluorescent powder, and the step of forming the second fluorescent glue layer on the first fluorescent glue layer and the substrate comprises: most of the second fluorescent powder in the second fluorescent glue layer is precipitated to form the precipitate layer and the clean glue layer by a precipitation process.

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