High-light-output LED package having graded refractive index

Abstract

A high-light-output LED package having a graded refractive index, comprising a ceramic substrate, a light-emitting chip, a filler and special-shaped quartz glass, wherein the light-emitting chip is arranged at the center of the ceramic substrate, the ceramic substrate is cylindrical, the filler is arranged directly above the light-emitting chip, the special-shaped quartz glass is hemispherical and the interior thereof is hollow, and the special-shaped quartz glass is bonded to the ceramic substrate; the top of an optical inner cavity of the special-shaped quartz glass is a plane, and the top of the optical inner cavity of the special-shaped quartz glass is in full contact with the top of the filler; the filler is a multi-layer filler; and the refractive index of the multi-layer filler decreases gradually. In the present invention, the special-shaped quartz glass covers a step with ceramic substrate dams, the multi-layer filler is completely attached to the top of the light-emitting chip and the special-shaped quartz glass, the refractive index of the multi-layer filler is between the refractive index of the ceramic substrate and the refractive index of the special-shaped quartz glass, and light is transmitted from an optically denser medium to an optically thinner medium, so as to achieve light output with the graded refractive index.

Description

A high light output LED package with gradually changed refractive index TECHNICAL FIELD

[0001] The present application belongs to the technical field of LED package, and particularly relates to a high light output LED package with gradually changed refractive index. BACKGROUND

[0002] The conventional ultraviolet lamp bead packaging structure mainly adopts ceramic substrate dam packaging, but due to the absorption and shielding effect of the ceramic substrate dam, the light power output of the small size lamp bead is limited.

[0003] Although the small size ceramic flat plate substrate plus fluororesin packaging process on the market can improve the light power output, most manufacturers cannot achieve mass production level, and the price is relatively high. There are also conventional small size lamp beads, and a filler is added between the chip and the lens in the internal structure, the filler is a carbon silicon compound, the refractive index of which is usually about 1.3, the chip surface sapphire (1.76-1.77) and quartz lens (1.44-1.46), the light path is from light dense medium to light sparse medium, and then to light dense medium, and part of the light output will be reflected or even totally reflected, resulting in reduced light output. SUMMARY

[0004] In view of the technical problem that the light output of the LED package will be partially reflected or even totally reflected, resulting in reduced light output, the present application provides a high light output LED package with gradually changed refractive index.

[0005] In order to solve the above technical problem, the technical scheme adopted by the present application is as follows:

[0006] A high light output LED package with gradually changed refractive index, comprising a ceramic substrate, a light emitting chip, a filler and a special-shaped quartz glass, the light emitting chip is arranged at the center of the ceramic substrate, the ceramic substrate is cylindrical, the filler is arranged directly above the light emitting chip, the special-shaped quartz glass is a hollow semispherical shape, and the special-shaped quartz glass is bonded to the ceramic substrate; the top of the light inner cavity of the special-shaped quartz glass is a plane, and the top of the light inner cavity of the special-shaped quartz glass is in full contact with the upper part of the filler; the filler adopts a multilayer filler; the multilayer filler comprises a first filler, a second filler and a third filler, the first filler is arranged on the light emitting chip, the second filler is arranged on the first filler, and the third filler is arranged on the second filler; the refractive indexes of the first filler, the second filler and the third filler decrease in turn.

[0007] The first filler is a fluorocarbon compound, the second filler is a carbon silicon compound, and the third filler is a carbon fluorine oxygen compound.

[0008] The density of the first filler is greater than the density of the second filler, and the density of the second filler is greater than the density of the third filler.

[0009] The refractive index of the first filler ranges from 1.66 to 1.76, the refractive index of the second filler ranges from 1.56 to 1.66, and the refractive index of the third filler ranges from 1.46 to 1.56.

[0010] The bottom of the special-shaped quartz glass is bonded to the ceramic substrate dam by welding of silicon glue or tin paste.

[0011] The ceramic substrate comprises a positive electrode surface, a negative electrode surface and a ceramic layer, the positive electrode surface and the negative electrode surface are arranged at the bottom of the ceramic layer, and the light emitting chip is arranged at the center of the upper surface of the ceramic layer.

[0012] The light emitting chip is electrically connected to the positive electrode surface and the negative electrode surface.

[0013] The ceramic substrate further comprises electroplated copper, a welding raised surface and a ceramic substrate dam, the electroplated copper is annularly arranged at the edge of the surface of the ceramic layer, the ceramic substrate dam is annularly arranged on the electroplated copper, and the welding raised surface is arranged at the bottom of the light emitting chip.

[0014] The light emitting chip is welded on the surface of the ceramic layer by eutectic welding and tin paste welding.

[0015] The light emitting chip, the first filler, the second filler and the third filler are bonded by piezoelectric or jet dispensing.

[0016] Compared with the prior art, the present application has the beneficial effects that:

[0017] After the ceramic substrate is welded with the light emitting chip, the filler is filled above the light emitting chip by piezoelectric or jet dispensing, the special-shaped quartz glass is covered on the step of the ceramic substrate dam, the single-layer filler or the multi-layer filler can be completely attached to the light emitting chip and the special-shaped quartz glass by piezoelectric or jet dispensing, and then the ultraviolet LED package is realized after baking. The refractive index of the filler is between the ceramic substrate and the special-shaped quartz glass, light is transmitted from the optically dense medium to the optically sparse medium, and light is mostly refracted and rarely reflected, so that the light refractive index gradually changes, the light extraction is effectively improved, and a small-size high-efficiency extraction package is realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the embodiments or the technical solutions of the present application in the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are only exemplary for those skilled in the art, and other drawings can be obtained by the provided drawings without creative labor.

[0019] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions that the present application can be implemented, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that the present application can produce, should still fall within the scope of the technical content disclosed by the present application.

[0020] Figure 1 is a cross-sectional view of the present application with a single layer of filler;

[0021] Figure 2 is a cross-sectional view of the ceramic substrate of the present application;

[0022] Figure 3 is a schematic diagram of the structure of the shaped quartz glass of the present application;

[0023] Figure 4 is a schematic diagram of the light path of the present application with a single layer of filler with a gradually changing refractive index;

[0024] Figure 5 is a cross-sectional view of the present application with a multi-layer filler;

[0025] Figure 6 is a schematic diagram of the light path of the present application with a multi-layer filler with a gradually changing refractive index.

[0026] Wherein: 1 is a ceramic substrate, 1-1 is a positive electrode surface, 1-2 is a negative electrode surface, 1-3 is a ceramic layer, 1-4 is electroplated copper, 1-5 is a soldered raised surface, 1-6 is a ceramic substrate dam, 2 is a light emitting chip, 3 is a single layer of filler, 4 is a shaped quartz glass, 5 is a first filler, 6 is a second filler, and 7 is a third filler. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, and are not all the embodiments. These descriptions are only for further illustrating the features and advantages of the present application, and are not a limitation on the claims of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0029] The terms "first", "second", "third", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0030] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. Example 1

[0031] In this embodiment, as shown in Figure 1, it includes a ceramic substrate 1, a light emitting chip 2, a filler and a special-shaped quartz glass 4. The ceramic substrate 1 plays the role of thermal conduction of the chip, and also plays the role of bearing the chip and the quartz glass, and also plays the role of welding with the PCB board. The light emitting chip 2 contains all wave bands of UVA, UVB, UVC, and the welding with the ceramic substrate 1 has eutectic welding mode and tin paste welding mode. The light emitted by the chip can realize the functions of sterilization and disinfection, air purification, food preservation, medical health, photocatalysis, etc. The filler adopts a single-layer filler 3, which is a kind of high-temperature-resistant material, can work stably for a long time in a high-temperature environment, is not easy to decompose or oxidize, has excellent chemical corrosion resistance, can resist the erosion of most acids, alkalis, solvents and other chemical substances, and is not easy to be affected by factors such as ultraviolet light, oxygen and moisture. The UV light refractive index of the single-layer filler 3 is within the range of 1.46-1.77, and the preferred one is perfluoropolyether. The single-layer filler 3 can be uniformly dispensed on the top of the light emitting chip by a piezoelectric dispensing machine or a spray dispensing machine. As shown in Figure 4, the violet light path is irradiated from the inner cavity of the package to the air, and the light is transmitted from the light-dense medium to the light-lean medium and then to the air, so that the light emitted by the chip can be extracted as much as possible. As shown in Figure 3, the special-shaped quartz glass 4 has a square bottom, which can be bonded with the ceramic substrate 1 by welding methods such as silicone and tin paste, and the light-emitting inner cavity thereof is a plane, which can realize effective contact between the filler and the top of the chip; the special-shaped quartz glass 4 is JJG2 type material, and the transmittance of UV wave band reaches more than 85%.

[0032] Further, as shown in Fig. 2, the ceramic substrate 1 comprises a positive electrode surface 1-1, a negative electrode surface 1-2, a ceramic layer 1-3, electroplated copper 1-4, a soldered raised surface 1-5 and a ceramic substrate dam 1-6. The thickness of the positive electrode surface 1-1 and the negative electrode surface 1-2 is 0.15 mm, and the surfaces are plated with metal copper, which serves as the circuit connection of the light emitting chip 2. The ceramic layer 1-3 is an important part of the heat conduction of the chip, and has a thermal conductivity of 30 W / (m·K)-170 W / (m·K), and is made of aluminum oxide or aluminum nitride. The electroplated copper 1-4 has a thickness of 0.065 mm, is connected to the ceramic layer 1-3 below and to the ceramic substrate dam 1-6 above, and is plated with nickel gold or nickel palladium gold on the surface. The soldered raised surface 1-5 has a height of 0.1 mm, and the light emitting chip is soldered thereto, which can increase the height of the light emitting chip 2 and can extract as much light as possible from the side surface of the light emitting chip 2. The height of the ceramic substrate dam 1-6 is 0.1 mm, which can limit the shape of the quartz glass 4 and avoid the center deviation of the shape of the quartz glass 4 during the operation process. Example 2

[0033] As shown in Fig. 5, the filler is a multi-layer filler, which comprises a first filler 5, a second filler 6 and a third filler 7. The first filler 5 is a fluorocarbon compound, the refractive index of the first filler 5 ranges from 1.66 to 1.76, the second filler 6 is a carbon silicon compound, the refractive index of the second filler 6 ranges from 1.56 to 1.66, and the third filler 7 is a fluorine oxygen compound, the refractive index of the third filler 7 ranges from 1.46 to 1.56. As shown in Fig. 6, the light path is from the first filler 5 to the second filler 6, and from the second filler 6 to the third filler 7, and the light path with gradually changing refractive index can fully extract the ultraviolet light. The density of the first filler 5, the second filler 6 and the third filler 7 gradually decreases, the viscosity gradually increases, and they are not miscible. The process can first point the first filler 5, then point the second filler 6, and finally point the third filler 7, which can realize the superposition of the multi-layer filler.

[0034] Compared with the conventional small size package, the light extraction rate of the embodiment can reach about 15-20% by simply using a spherical quartz lens. The light extraction rate can reach about 50%-60% by using a single layer filler 3 or a multi-layer filler and a shaped quartz glass 4, and the light extraction rate is obviously improved, which can be applied to small space high light output environment.

[0035] Compared with the conventional package made of a filler with a refractive index of 1.3, the light extraction effect of the embodiment can also reach about 30%, but the working principle is from a light dense medium to a light sparse medium, and then to a light dense medium, which will reflect a part of the light in the form of reflection, resulting in a part of the light loss, and failing to achieve high extraction effect.

[0036] The filler of the embodiment is fluorocarbon, carbosilicon or fluorocarbon oxide, the manufacturing capacity has been mature, the package point filler is currently in the sample stage, and the equipment mass production manufacturing capacity can realize single layer filler or multi-layer filler filling.

[0037] The package is currently in the small batch stage, and it is verified that the optical power of the 4545 chip can reach 150mW-200mW under the structure of the 3535 ceramic substrate. After normal temperature aging, high temperature aging, constant temperature and humidity aging, cold and hot impact test, the chip light decay is below 10%, the filler does not yellow and crack.

[0038] Comparing the patent with application number 201710416788.8, the invention is arranged in an array structure and can emit array-shaped light. The light source assembly includes a substrate, an LED package, an optical cover, and at least one filler layer, which belongs to the modification of the application end. The LED package is welded on the circuit board (aluminum substrate, copper substrate, etc.). The optical cover is arranged above the circuit board, which wraps the LED package. The filler layer between the LED package and the optical cover fills the glue material with different refractive indexes, thereby achieving good penetration efficiency. The patent improves the light extraction from the external structure of the LED package, while the embodiment fills the refractive index gradient material between the light emitting chip and the quartz glass inside the LED package to achieve higher light extraction rate, which belongs to the internal structure improvement of the LED package.

[0039] Comparing the patent with application number 201710416788.8, the 130 filler layer (and other filler layers) between the LED package and the optical cover is realized by molding process, while the single layer or multi-layer filler inside the LED package of the embodiment can be directly realized by piezoelectric or jet dispensing, and the manufacturing process has essential difference.

[0040] The above only describes the preferred embodiment of the present application in detail, but the present application is not limited to the above embodiment. Within the knowledge range of ordinary skilled persons in the art, various changes can be made without departing from the purpose of the present application, and various changes should be included in the protection scope of the present application.

Claims

1. A high-brightness-output LED package with a gradually changing refractive index, characterized in that: The device includes a ceramic substrate (1), a light-emitting chip (2), a filler, and a shaped quartz glass (4). The light-emitting chip (2) is located at the center of the ceramic substrate (1), which is cylindrical. The filler is located directly above the light-emitting chip (2). The shaped quartz glass (4) is a hollow hemisphere and is bonded to the ceramic substrate (1). The top of the optical cavity of the shaped quartz glass (4) is flat and is in full contact with the top of the filler. The filler is a multi-layered filler. The multi-layered filler includes a first filler (5), a second filler (6), and a third filler (7). The first filler (5) is located on the light-emitting chip (2), the second filler (6) is located on the first filler (5), and the third filler (7) is located on the second filler (6). The refractive indices of the first filler (5), the second filler (6), and the third filler (7) decrease sequentially.

2. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The first filler (5) is a fluorocarbon compound, the second filler (6) is a silicon carbide compound, and the third filler (7) is a fluorocarbon oxide compound.

3. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The density of the first filler (5) is greater than the density of the second filler (6), and the density of the second filler (6) is greater than the density of the third filler (7).

4. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The refractive index of the first filler (5) is in the range of 1.66-1.76, the refractive index of the second filler (6) is in the range of 1.56-1.66, and the refractive index of the third filler (7) is in the range of 1.46-1.

56.

5. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The bottom of the irregular quartz glass (4) is bonded to the ceramic substrate dam (1-6) by welding with silicone or solder paste.

6. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The ceramic substrate (1) includes a positive electrode surface (1-1), a negative electrode surface (1-2), and a ceramic layer (1-3). The positive electrode surface (1-1) and the negative electrode surface (1-2) are both disposed at the bottom of the ceramic layer (1-3), and the light-emitting chip (2) is disposed at the center of the upper surface of the ceramic layer (1-3).

7. The LED package with a gradually changing refractive index and high light output according to claim 6, characterized in that: The light-emitting chip (2) is electrically connected to the positive electrode surface (1-1) and the negative electrode surface (1-2).

8. The LED package with a gradually changing refractive index and high light output according to claim 6, characterized in that: The ceramic substrate (1) further includes electroplated copper (1-4), a welding elevation surface (1-5), and a ceramic substrate dam (1-6). The electroplated copper (1-4) is arranged in a ring at the edge of the surface of the ceramic layer (1-3). The ceramic substrate dam (1-6) is arranged in a ring on the electroplated copper (1-4). The welding elevation surface (1-5) is arranged at the bottom of the light-emitting chip (2).

9. The LED package with a gradually changing refractive index and high light output according to claim 6, characterized in that: The light-emitting chip (2) is welded to the surface of the ceramic layer (1-3) by eutectic bonding and solder paste bonding.

10. The LED package with a gradually changing refractive index and high light output according to claim 1, characterized in that: The light-emitting chip (2), the first filler (5), the second filler (6) and the third filler (7) are all bonded together by piezoelectric or jet adhesive.

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