An LED package with a gradually changing refractive index and high light output

Abstract

The present invention belongs to the technical field of LED packages, and particularly relates to an LED package with a gradually changing refractive index and high light output, which includes 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 hemispherical, and the special-shaped quartz glass is bonded to the ceramic substrate. After the light-emitting chip is welded on the ceramic substrate in the present invention, the filler is dispensed by piezoelectric or spraying method directly above the light-emitting chip, and the special-shaped quartz glass is covered on the step with a dam on the ceramic substrate. The single-layer filler or multi-layer fillers are completely attached to the area above the light-emitting chip and the special-shaped quartz glass. The refractive index of the filler is between that of the ceramic substrate and the special-shaped quartz glass. When light travels from an optically denser medium to an optically rarer medium, more refraction and less reflection of light occur, realizing the gradually changing output of the light refractive index.

Description

Technical Field

[0001] The present invention belongs to the technical field of LED packages, and particularly relates to an LED package with a gradually changing refractive index and high light output. Background Art

[0002] The traditional packaging structure of ultraviolet lamp beads mainly uses ceramic substrate dam packaging. However, due to the absorption and blocking effects of the ceramic substrate dam, the light power output of small-sized lamp beads is limited.

[0003] At present, although the small-sized ceramic flat 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-sized lamp beads with a filler added between the chip and the lens in the internal structure. The filler is a carbon silicon compound with a refractive index usually around 1.3. The chip surface is sapphire (1.76 - 1.77) and the quartz lens is (1.44 - 1.46). The light path goes from an optically denser medium to an optically thinner medium and then to an optically denser medium, and there will be partial reflection or even total reflection in the light output, resulting in a reduction in light output. Summary of the Invention

[0004] Aiming at the technical problem that there will be partial reflection or even total reflection in the light output of the above-mentioned LED package, resulting in a reduction in light output, the present invention provides an LED package with a gradually changing refractive index and high light output.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] An LED package with a gradually changing refractive index and high light output, 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 hemispherical shape with a hollow interior and is bonded to the ceramic substrate.

[0007] The ceramic substrate includes a positive electrode surface, a negative electrode surface, and a ceramic layer. The positive electrode surface and the negative electrode surface are both arranged at the bottom of the ceramic layer. The light-emitting chip is arranged at the center of the upper surface of the ceramic layer and is electrically connected to the positive electrode surface and the negative electrode surface.

[0008] The ceramic substrate further includes electroplated copper, a welding heightening surface, and a ceramic substrate dam. The electroplated copper is arranged in a ring at the edge of the surface of the ceramic layer. The ceramic substrate dam is arranged in a ring on the electroplated copper. The welding heightening surface is arranged at the bottom of the light-emitting chip.

[0009] The bottom of the special-shaped quartz glass is adhesively bonded to the ceramic substrate dam through soldering with silicone or solder paste. The top of the optical inner cavity of the special-shaped quartz glass is flat, and the top of the optical inner cavity of the special-shaped quartz glass is in full contact with the upper part of the filler.

[0010] The light-emitting chip is soldered to the surface of the ceramic layer through eutectic soldering and solder paste soldering methods.

[0011] The filler uses a single-layer filler or a multi-layer filler.

[0012] The single-layer filler uses a fluorocarbon compound, a carbon-silicon compound, or a fluorocarbon oxide compound. The refractive index range of the single-layer filler is 1.46 - 1.77. The single-layer filler is adhesively bonded to the light-emitting chip through piezoelectric or jet dispensing.

[0013] The multi-layer filler includes 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.

[0014] The first filler uses a fluorocarbon compound, and the refractive index range of the first filler is 1.66 - 1.76. The second filler uses a carbon-silicon compound, and the refractive index range of the second filler is 1.56 - 1.66. The third filler uses a fluorocarbon oxide compound, and the refractive index range of the third filler is 1.46 - 1.56. 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.

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

[0016] The beneficial effects of the present invention compared with the prior art are as follows:

[0017] After the light-emitting chip is soldered on the ceramic substrate in the present invention, the filler is dispensed through piezoelectric or jetting methods directly above the light-emitting chip, and the special-shaped quartz glass is covered on the step with the ceramic substrate dam. The single-layer filler or multi-layer filler can be completely attached to the upper part of the light-emitting chip and the special-shaped quartz glass through piezoelectric or jet dispensing, and then baked to realize the ultraviolet LED package. The refractive index of the filler is between the ceramic substrate and the special-shaped quartz glass. Light is transmitted from the optically denser medium to the optically rarer medium, and more refraction and less reflection occur, realizing a gradual change in the refractive index of light output, which can effectively improve light extraction to realize a small-size and high-efficiency extraction package. Description of the Drawings

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0019] The structures, ratios, sizes, etc. shown in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

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

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

[0022] Figure 3 It is a schematic structural diagram of the special-shaped quartz glass of the present invention;

[0023] Figure 4 It is a schematic diagram of the refractive index gradient optical path of the single-layer filler of the present invention;

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

[0025] Figure 6 It is a schematic diagram of the refractive index gradient optical path of the multi-layer filler of the present invention.

[0026] Among them: 1 is the ceramic substrate, 1-1 is the positive electrode surface, 1-2 is the negative electrode surface, 1-3 is the ceramic layer, 1-4 is the electroplated copper, 1-5 is the welding heightening surface, 1-6 is the ceramic substrate dam, 2 is the light-emitting chip, 3 is the single-layer filler, 4 is the special-shaped quartz glass, 5 is the first filler, 6 is the second filler, and 7 is the third filler. Specific embodiments

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. These descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope protected by the present application.

[0028] The following will further describe in detail the specific implementation manners of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0029] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0030] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0031] Embodiment 1

[0032] In this embodiment, as Figure 1As described above, it includes a ceramic substrate 1, a light-emitting chip 2, a filler, and a special-shaped quartz glass 4. The ceramic substrate 1 functions as a thermoelectric conductor for the chip, and also serves to carry the chip and the quartz glass, and to weld with the PCB board. The light-emitting chip 2 includes all bands of UVA, UVB, and UVC. The welding with the ceramic substrate 1 has eutectic welding and solder paste welding methods. The light emitted by the chip can achieve functions such as sterilization, air purification, food preservation, medical and health care, and photocatalysis. The filler uses a single-layer filler 3, which is a substance with high-temperature resistance performance and can work stably for a long time in a high-temperature environment without thermal decomposition or oxidation. At the same time, it has excellent chemical corrosion resistance and can withstand the erosion of most acids, alkalis, solvents and other chemical substances, and is not easily affected by factors such as ultraviolet rays, oxygen, and moisture. The UV light refractive index of the single-layer filler 3 is in the range of 1.46 - 1.77, and perfluoropolyether is preferred. The single-layer filler 3 can be evenly dispensed above the light-emitting chip through a piezoelectric dispenser or a jet dispenser. As Figure 4 shown, the purple light path irradiates from the inner cavity of the package to the air, from an optically denser medium to an optically rarer medium and then transmitted to the air, and the light emitted by the chip can be extracted as much as possible. As Figure 3 shown, the bottom of the special-shaped quartz glass 4 is square and can be bonded to the ceramic substrate 1 by welding methods such as silicone and solder paste. Its light-emitting inner cavity is flat, which can realize effective contact between the filler and above the chip; the special-shaped quartz glass 4 is made of JJG2 type material, and the transmittance of the UV band reaches more than 85%.

[0033] Furthermore, as Figure 2 shown, the ceramic substrate 1 includes a positive electrode surface 1-1, a negative electrode surface 1-2, a ceramic layer 1-3, electroplated copper 1-4, a welding heightening surface 1-5, and a ceramic substrate dam 1-6. The thicknesses of both the positive electrode surface 1-1 and the negative electrode surface 1-2 are 0.15 mm, and the surfaces are plated with copper, which functions as the circuit connection of the light-emitting chip 2. The ceramic layer 1-3 is an important part of the chip heat conduction, and its thermal conductivity is about 30 - 170 W / (m·K), and its material is alumina 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 its surface is plated with nickel-gold or nickel-palladium-gold. The height of the welding heightening surface 1-5 is 0.1 mm, and the light-emitting chip is welded to it, which can increase the height of the light-emitting chip 2 and can extract the side light of the light-emitting chip 2 as much as possible. The height of the ceramic substrate dam 1-6 is 0.1 mm, which can be positioned to the special-shaped quartz glass 4 to avoid the center offset of the special-shaped quartz glass 4 during the operation process.

[0034] Example Two

[0035] As Figure 5As shown, the filler uses multiple layers of fillers, including a first filler 5, a second filler 6, and a third filler 7. The first filler 5 uses a fluorocarbon compound, and the refractive index range of the first filler 5 is 1.66 - 1.76. The second filler 6 uses a carbon silicon compound, and the refractive index range of the second filler 6 is 1.56 - 1.66. The third filler 7 uses a fluorocarbon oxide compound, and the refractive index range of the third filler 7 is 1.46 - 1.56. As Figure 6 shown, the light path from the first filler 5 to the second filler 6 and from the second filler 6 to the third filler 7, with a gradually changing refractive index light path mode, can fully extract ultraviolet light. The densities of the first filler 5, the second filler 6, and the third filler 7 gradually decrease, and the viscosities gradually increase, and they are immiscible. The process can first dot the first filler 5, then dot the second filler 6, and then dot the third filler 7, which can achieve the superposition of multiple layers of fillers.

[0036] Compared with the traditional small - size package, in this embodiment, simply using a spherical quartz lens, the light extraction rate can reach about 15 - 20%. Using a single - layer filler 3 or multiple - layer fillers and then using a shaped quartz glass 4, the light extraction rate can reach about 50 - 60%, and the light extraction rate is significantly improved, which can be applied to environments with high light output in small spaces.

[0037] Compared with the package made of a traditional filler with a refractive index of 1.3, the light extraction effect of this embodiment can also reach about 30%. However, its working principle is from an optically denser medium to an optically rarer medium and then to an optically denser medium, and a part of the light will be reflected back in the form of reflection, losing a part of the light and failing to achieve a high extraction effect;

[0038] The fillers are fluorocarbon compounds, carbon silicon compounds, and fluorocarbon oxide compounds, and their manufacturing capabilities are already mature. The dotting of fillers in the package is currently in the sample stage, and the mass - production manufacturing capacity of the equipment can achieve the filling of single - layer fillers or multiple - layer fillers;

[0039] This package is currently in the small - batch stage. Verifying that under the structure of a 4545 chip on a 3535 ceramic substrate, its optical power can reach 150 - 200 mW. After normal - temperature aging, high - temperature aging, constant - temperature and constant - humidity aging, and thermal shock tests, the optical decay of the chip is below 10%, and there is no yellowing or cracking phenomenon in the filler.

[0040] Comparing with the patent with the application number 201710416788.8, the invention is a structure arranged in an array that can emit light in an array shape. The light source assembly includes a substrate, an LED package, an optical cover, and at least one gap-filling layer, which belongs to the transformation at the application end. The LED package is welded on a circuit board (such as an aluminum substrate or a copper substrate). An optical cover is arranged above the circuit board, which wraps the LED package. The gap-filling layer between the LED package and the optical cover is filled with glue materials of different refractive indexes, so as to achieve good penetration efficiency. This patent improves light extraction from the external structure of the LED package, while in this embodiment, a material with a gradually changing refractive index is filled between the light-emitting chip inside the LED package and the quartz glass to achieve a higher light extraction rate, which belongs to the improvement of the internal structure of the LED package.

[0041] Comparing with the patent with the application number 201710416788.8, the 130 gap-filling layer (and other affiliated gap-filling layers) between the LED package and the optical cover are all completed through a molding process, while in this embodiment, the single-layer or multi-layer fillers inside the LED package can be directly realized by piezoelectric or jet dispensing, and there are essential differences in their manufacturing processes.

[0042] Only the preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A LED package with a gradient refractive index and high light output, characterized in that: The invention comprises a ceramic substrate (1), a light-emitting chip (2), a filler and a shaped quartz glass (4), wherein the light-emitting chip (2) is arranged at the center of the ceramic substrate (1), the ceramic substrate (1) is cylindrical, the filler is arranged directly above the light-emitting chip (2), the shaped quartz glass (4) is hemispherical with a hollow interior, and the shaped quartz glass (4) is bonded to the ceramic substrate (1); the bottom of the shaped quartz glass (4) is bonded to the ceramic substrate dam (1-6) by means of a soldering method using silica gel or solder paste, the top of the light cavity of the shaped quartz glass (4) is a plane, and the top of the light cavity of the shaped quartz glass (4) is in full contact with the top of the filler; the filler is a multi-layer filler; the multi-layer filler comprises a first filler (5), a second filler (6) and a third filler (7). Three fillers (7), wherein the first filler (5) is arranged on the light emitting chip (2), the second filler (6) is arranged on the first filler (5), and the third filler (7) is arranged on the second filler (6); the first filler (5) is made of fluorocarbon, and the refractive index of the first filler (5) is in the range of 1.66-1.76; the second filler (6) is made of carbon silicon, and the refractive index of the second filler (6) is in the range of 1.56-1.66; the third filler (7) is made of fluorocarbon oxygen, and the refractive index of the third filler (7) is in the range of 1.46-1.56; 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).

2. The LED package with a gradient refractive index and high light output according to claim 1, characterized in that: The ceramic substrate (1) comprises 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 arranged at the bottom of the ceramic layer (1-3); the light-emitting chip (2) is arranged at the center of the upper surface of the ceramic layer (1-3); and the light-emitting chip (2) is electrically connected to the positive electrode surface (1-1) and the negative electrode surface (1-2).

3. The LED package with a gradient refractive index and high light output according to claim 2, characterized in that: The ceramic substrate (1) further comprises electroplated copper (1-4), a soldering heightening surface (1-5) and a ceramic substrate dam (1-6); the electroplated copper (1-4) is arranged in an annular shape at the edge of the surface of the ceramic layer (1-3); the ceramic substrate dam (1-6) is arranged in an annular shape on the electroplated copper (1-4); and the soldering heightening surface (1-5) is arranged at the bottom of the light-emitting chip (2).

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

5. The LED package with a gradient 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 dispensing.

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