CN108269902A - A kind of LED encapsulation structure and its packaging method - Google Patents

Abstract

The present invention provides an LED package structure, which includes a package body. The package body includes: a substrate, a kovar alloy metal frame on the substrate, a conductive layer on the kovar alloy metal frame, and a crystal-bonding area on the conductive layer. The crystal area is used to install LED chips; a glass substrate is installed on the crystal bonding area, and the outer surface of the glass substrate is covered with a protective cover. The outer surface of the protective cover is a concave-convex structure; the package body also includes edge filters and diffusers, diffuse The body is used to receive the light reflected from the edge filter. Through the above encapsulation structure, the present invention can make the LED have fast heat dissipation, UV radiation resistance, high temperature resistance, yellowing resistance, and facilitate industrialization; the path of the excited light is consistent, and there is no color difference or very small color difference from all angles; through The conductive layer can be used to reflect the light emitted by the LED chip and become a reflective layer; by adopting a concave-convex structure for the protective cover, the roughening of the surface of the LED package is effectively and simply realized, thereby improving the luminous efficiency of the high-efficiency LED.

Description

A kind of LED packaging structure and packaging method thereof

technical field

The invention relates to the field of semiconductor packaging, in particular to an LED packaging structure and a packaging method thereof.

Background technique

LED is called the fourth-generation lighting source or green light source. It has the characteristics of energy saving, environmental protection, long life, and small size. It is widely used in various indications, displays, decorations, backlights, general lighting, and urban night scenes. According to different functions, it can be divided into five categories: information display, signal lights, vehicle lamps, LCD backlight, and general lighting.

LED products are mainly used in the three major fields of backlight, color screen and indoor lighting. In the future, under the influence of factors such as the decline in product prices caused by the continuous maturity of technology and the rise of a new round of global ban on the sale of incandescent lamps, indoor lighting will replace backlights and become the fastest growing segment of LED in the future. In addition, in recent years, driven by product upgrading factors such as small-pitch display screens, the growth rate of LED products has also continued to increase, showing a steady growth trend.

At present, commonly used LED packages have slow heat dissipation, are not resistant to UV radiation, are not resistant to high temperature, are easy to turn yellow, and are not convenient for industrialization.

Contents of the invention

The object of the present invention is to provide an LED package structure and a package method thereof which are simple in structure, convenient for industrialization, small in color difference, and good in luminous effect.

The purpose of the present invention is achieved by adopting the following technical solutions.

An LED package structure, comprising a package body, the package body comprising:

Substrate;

A kovar alloy metal frame is arranged above the substrate, and the size of the outer edge of the kovar alloy metal frame is smaller than the size of the substrate;

The Kovar alloy metal frame is quadrilateral, and a conductive layer is arranged on the Kovar alloy metal frame, and a crystal-bonding area is arranged on the conductive layer;

The crystal-bonding area is used to install LED chips;

A glass substrate is installed on the crystal-bonding area, which includes a glass substrate and a plurality of pixels vertically distributed on the glass substrate, each pixel includes a plurality of sub-pixel microcavities, and the outer periphery of the glass substrate is covered with There is a protective cover, and the outer surface of the protective cover is a concave-convex structure; and

An edge filter and a diffuser are also included in the package body, and the diffuser is used for receiving light reflected from the edge filter.

Specifically, the substrate is an aluminum nitride substrate with metal lines.

Specifically, the Kovar alloy metal frame is made of Mo-Ni-Cu alloy, and the Kovar alloy metal frame is welded to the substrate.

Specifically, the LED chip is soldered to the die-bonding area.

Specifically, the material of the conductive layer is selected from any one of metals, conductive compounds, and polymer materials mixed with conductive substances, and the conductive layer is: a single-layer conductive layer or multiple conductive layers and insulating layers are formed alternately the conductive layer.

Specifically, the concave-convex structure is a microstructure, and the order of magnitude of the microstructure is nanoscale.

Further, the sub-pixel microcavity is arranged on the glass substrate, and an opaque anode layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a translucent cathode layer are sequentially stacked upward from the glass substrate, each The top surfaces of the layers facing away from the glass substrate have the same curvature.

The present invention provides another LED packaging method, comprising the following steps:

Step 1. Welding metal lines on a sheet substrate, and welding the Kovar alloy metal frame on the substrate;

Step 2, welding a conductive layer on the Kovar metal frame;

Step 3, fixing the LED chip on the conductive layer on the upper surface by welding;

Step 4. Install a glass substrate above the LED chip, and set a protective cover on the periphery of the glass substrate, so that the packaging of the LED lamp bead is completed;

Step 5. Using laser cutting, the LED lamp beads are cut off from the sheet-like substrate, and divided into individual LED lamp beads.

Specifically, the substrate is an aluminum nitride substrate, the Kovar metal frame is made of Mo-Ni-Cu alloy, the aluminum nitride substrate and the Kovar alloy are welded under vacuum and high temperature conditions, and the solder can Ag70-Cu28-Ti2 active solder is used.

Specifically, the size of the outer edge of the Kovar metal frame is smaller than the size of the substrate.

The beneficial effects of the present invention are as follows: 1. The purpose of the Kovar alloy metal frame being smaller than the base plate is to facilitate mass production of the structure. Cut from the substrate, the cutting position is the place where the aluminum nitride is larger than the Kovar metal frame;

2. Through the above packaging structure, the LED can dissipate heat quickly, resist UV radiation, high temperature and yellowing;

3. Make the path of the excited light consistent, and there is no or very little chromatic aberration from all angles;

4. The conductive layer can not only be used to arrange the circuit, but also can be used to reflect the light emitted by the LED chip to become a reflective layer;

5. By adopting a concave-convex structure for the protective cover, the roughening of the surface of the LED package is effectively and simply realized, thereby improving the luminous efficiency of the high-efficiency LED.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a schematic diagram of an LED packaging structure provided by a first embodiment of the present invention;

2 is a schematic diagram of the outer surface of a sub-pixel microcavity;

3 is a schematic structural diagram of a sub-pixel microcavity;

Fig. 4 is the schematic diagram of the light path of sub-pixel microcavity;

Fig. 5 is a schematic diagram of the light path in Fig. 3;

6 is a schematic diagram of an LED package structure provided by a second embodiment of the present invention;

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Please refer to FIG. 1 , which is an LED package structure provided by the first embodiment of the present invention, including a package body 100 , the package body includes: a substrate 110 , and the substrate 110 is an aluminum nitride substrate 110 with metal lines. The aluminum nitride substrate 110 is a type of ceramic substrate. The aluminum nitride substrate 110 has a higher thermal conductivity, the thermal conductivity of the aluminum nitride substrate 110 is 170-230w/mk, and the higher the thermal conductivity, the more it can help the product to dissipate heat. Moreover, the aluminum nitride substrate 110 has a more matching coefficient of thermal expansion, so that the LED lamp will not be deformed too much when the temperature difference changes drastically, resulting in desoldering of the internal metal circuit. At the same time, the aluminum nitride substrate 110 has better solderability and can be repeatedly soldered.

In this specific embodiment, the aluminum nitride substrate 110 has different manufacturing methods according to product requirements, including thin film technology, thick film technology, direct copper clad method and laser activated metallization technology.

Further, a kovar alloy metal frame 120 is arranged above the substrate 110, the kovar alloy metal frame 120 is quadrangular, the outer edge size of the kovar alloy metal frame 120 is smaller than the size of the substrate 110, and the kovar alloy metal frame 120 is smaller than the substrate 110. The purpose of the small size is to facilitate mass production. After the entire package is completed, laser cutting is used to cut the lamp beads from the sheet-shaped large substrate. The cutting position is the aluminum nitride and Kovar alloy metal. Box 120 out of place.

Specifically, the material of the Kovar alloy metal frame 120 is Mo-Ni-Cu alloy, and the aluminum nitride substrate 110 and the Kovar alloy metal frame 120 are welded under vacuum and high temperature conditions, and the solder can be Ag70-Cu28- Ti2 active solder. Before welding, grind the welding surface of the aluminum nitride substrate 110 with sandpaper to make the mortgaged surface smooth, then clean it with alcohol, put it in acetone solution and use ultrasonic cleaning for about 15 minutes to remove oil stains on the welded surface. Before using Ag70-Cu28-Ti2 active solder, remove the oxide layer on the surface, then put it into acetone solution for ultrasonic cleaning, and finally perform welding connection in a vacuum furnace with a vacuum degree better than 1.0ⅹ10 ^-3 Pa.

In this specific embodiment, the welding temperature is 1150K, the heating rate is 10° C./min, and the temperature is kept at 1000K and 1150K for 10 minutes respectively.

Further, a conductive layer (not shown) is provided on the Kovar metal frame 120 . Specifically, the material of the conductive layer is selected from any one of metals, conductive compounds and polymer materials mixed with conductive substances, and the conductive layer can be a single-layer conductive layer or a conductive layer formed alternately by multiple conductive layers and insulating layers, The conductive layer can not only be used to arrange circuits, but also can be used to reflect light emitted by LED chips (not shown) to become a reflective layer.

Further, a die-bonding area (not shown) is provided on the conductive layer, and the die-bonding area is used for mounting LED chips, and the LED chips are soldered to the die-bonding area.

Further, please refer to FIGS. 2-3 , a glass substrate 200 is installed on the crystal bonding area, which includes a glass substrate 200 and a plurality of pixels vertically distributed on the glass substrate 200, and each pixel includes a plurality of sub-pixel microcavity. In this embodiment, each pixel includes three sub-pixel microcavities: a red sub-pixel microcavity 201 , a green sub-pixel microcavity 202 and a blue sub-pixel microcavity 203 . Each sub-pixel microcavity is in the shape of a semi-cylindrical and semicircular in cross-section. In this way, the path of the excited light in the microcavity is the same, and the resonance spectrum generated is also the same. Therefore, it can be seen from all angles There will be no color deviation. The sub-pixel microcavity is arranged on the glass substrate, and an opaque anode layer 210 (such as Ag), a barrier layer 220 (such as Ag20), a hole transport layer 230 (NPB), and a light emitting layer are sequentially stacked from the glass substrate 200 upwards. Layer 240 (Alg3), electron transport layer 250 (Al/LiF) and semi-transparent cathode layer 260 (eg Ag). The opaque anode layer 210 is arc-shaped on the glass substrate, and the other layers are sequentially stacked fan-shaped layers, both ends are located on the glass substrate 200, and each layer has the same curvature. During fabrication, a grayscale mask is used to create the shape of each layer of film.

For further clarity, the scheme adopted by the present invention can improve the color difference problem of LEDs. To prove its effect in principle, please refer to Figure 4. Light 1 is along the vertical direction of each layer, so light 1 cannot form resonance in the sub-pixel microcavity, and part of light 4 exits the sub-pixel microcavity.

The emission wavelength of the sub-pixel microcavity can be resonated in the cavity formed by the opaque anode layer, part of the light 2 exits the cavity; and the light 3 deviates from the vertical direction of each layer, so it can be expressed by the following formula:

λ=2πL/(2πm-|Φ1|-|Φ2|)

Among them, Φ1 and Φ2 respectively represent the phase shift generated on the interface of the opaque anode layer 210 and the semitransparent cathode layer 260, and the expressions are as follows:

Φ1,2=arctan[2Kmncosθ/(n2cos2θ-Nm2-Km2)] (S polarized light)

Φ1,2=arctan{2ncosθ(Nm2Km+Km3)/[n2(Nm2+Km2)-cos2θ(Nm2-Km2)2]} (P polarized light)

Among them, Nm and Km represent the refractive index and extinction coefficient of the metal, respectively; θ is the angle between the light generated in the device and the metal electrode and the normal direction of the electrode; n is the refractive index of the organic matter adjacent to the metal.

According to the above formula, the resonant wavelength in the sub-pixel microcavity is related to the wavelength, while the non-resonant wavelength is only related to the light-emitting material, so the spectra of light 2 and light 4 exiting the sub-pixel microcavity are different, so The color coordinate values are also different, so there will be a color difference between light 2 and light 4 when the human eye sees it.

After the above-mentioned in-depth analysis and research, after redesigning the LED, analyze the optical path of the LED, please refer to Figure 5. Light 1 and light 3 propagate along the axial direction of each curved layer, so resonance can be formed in the sub-pixel microcavity, and the emitted light 2 and light 4 have the same spectrum, so the color coordinate values are the same. However, light 5 and light 7 do not propagate along the axial direction of each layer, so no resonance is formed in the sub-pixel microcavity, and part of light 6 and light 8 exit the cavity, and always overlap with resonant light. Therefore, no matter which angle of view this structure is viewed at, there will be two parts of light: one part is the light that resonates in the sub-pixel microcavity and then emerges. This part of the light has a stronger intensity and narrower spectral lines, and the other part is non-resonant. Outgoing light, this part of the light intensity is weak and the spectral lines are broad. Since the shape of the sub-pixel microcavity in this embodiment is set as a semicircle, the spectrum of the resonant light is the same no matter which viewing angle is viewed, and the spectrum of the non-resonant light is also the same, so no matter which viewing angle is viewed, the color coordinates The values are all the same, thereby reducing chromatic aberration.

In addition, the semi-cylindrical shape of each sub-pixel microcavity can be arranged horizontally, that is, the axis direction of the semi-cylindrical pixel is horizontal, so that there is no chromatic aberration when viewed in the up and down direction, but there is chromatic aberration when viewed in the left and right directions; Vertically arranged, that is, the axis direction of the semi-cylindrical pixels is vertical, so there is no chromatic aberration when viewed in the left and right directions, but there is chromatic aberration when viewed in the up and down direction.

Further, the outer surface of the glass substrate 200 is covered with a protective cover (not shown), the outer surface of the protective cover is a concave-convex structure, the concave-convex structure is a microstructure, and the order of magnitude of the microstructure is nanoscale. By using the protective cover with a concave-convex structure , effectively and simply realize the roughening of the surface of the LED package, thereby improving the luminous efficiency of the high-efficiency LED.

Further, the package body also includes an edge filter and a diffuser, and the diffuser is used to receive light reflected from the edge filter, wherein the edge filter is placed above the LED chip, and its transmission edge follows the incident light Angle increases and shifts to shorter wavelengths. The edges of the low- and high-wavelength filters shift as the angle of incidence increases, resulting in increased reflection of LED radiation as a function of the angle of incidence of the illumination.

Please refer to 6, which is an LED package structure provided by the second embodiment of the present invention, including a package body 100, the package body includes: a substrate 110, the substrate 110 is an aluminum nitride substrate 110 with metal lines. The aluminum nitride substrate 110 is a type of ceramic substrate. The aluminum nitride substrate 110 has a higher thermal conductivity, the thermal conductivity of the aluminum nitride substrate 110 is 170-230w/mk, and the higher the thermal conductivity, the more it can help the product to dissipate heat. Moreover, the aluminum nitride substrate 110 has a more matching coefficient of thermal expansion, so that the LED lamp will not be deformed too much when the temperature difference changes drastically, resulting in desoldering of the internal metal circuit. At the same time, the aluminum nitride substrate 110 has better solderability and can be repeatedly soldered.

In this specific embodiment, the aluminum nitride substrate 110 has different manufacturing methods according to product requirements, including thin film technology, thick film technology, direct copper clad method and laser activated metallization technology.

Further, a kovar alloy metal frame 120 is arranged above the substrate 110, the kovar alloy metal frame 120 is quadrangular, the outer edge size of the kovar alloy metal frame 120 is smaller than the size of the substrate 110, and the kovar alloy metal frame 120 is smaller than the substrate 110. The purpose of the small size is to facilitate mass production. After the entire package is completed, laser cutting is used to cut the lamp beads from the sheet-shaped large substrate. The cutting position is the aluminum nitride and Kovar alloy metal. Box 120 out of place.

Specifically, the material of the Kovar alloy metal frame 120 is Mo-Ni-Cu alloy, and the aluminum nitride substrate 110 and the Kovar alloy metal frame 120 are welded under vacuum and high temperature conditions, and the solder can be Ag70-Cu28- Ti2 active solder. Before welding, grind the welding surface of the aluminum nitride substrate 110 with sandpaper to make the mortgaged surface smooth, then clean it with alcohol, put it in acetone solution and use ultrasonic cleaning for about 15 minutes to remove oil stains on the welded surface. Before using Ag70-Cu28-Ti2 active solder, remove the oxide layer on the surface, then put it into acetone solution for ultrasonic cleaning, and finally perform welding connection in a vacuum furnace with a vacuum degree better than 1.0ⅹ10 ^-3 Pa.

In this specific embodiment, the welding temperature is 1150K, the heating rate is 10° C./min, and the temperature is kept at 1000K and 1150K for 10 minutes respectively.

Further, a conductive layer (not shown) is provided on the Kovar metal frame 120 . Specifically, the material of the conductive layer is selected from any one of metals, conductive compounds and polymer materials mixed with conductive substances, and the conductive layer can be a single-layer conductive layer or a conductive layer formed alternately by multiple conductive layers and insulating layers, The conductive layer can not only be used to arrange circuits, but also can be used to reflect light emitted by LED chips (not shown) to become a reflective layer.

Further, a die-bonding area (not shown) is provided on the conductive layer, and the die-bonding area is used for mounting LED chips, and the LED chips are soldered to the die-bonding area.

Further, a flat glass substrate 200 is installed on the crystal bonding area, and the size of the glass substrate 200 is exactly the same as that of the Kovar alloy metal frame 120 .

Further, the package body also includes an edge filter and a diffuser, the diffuser is used to receive light reflected from the edge filter, wherein the edge filter is placed above the LED chip, and its transmission edge increases with the incident angle of light to shorter wavelengths. The edges of the low- and high-wavelength filters shift as the angle of incidence increases, resulting in increased reflection of LED radiation as a function of the angle of incidence of the illumination.

The present invention provides another LED packaging method, comprising the following steps:

Step 1. Solder the circuit with metal on the sheet substrate 110 , and weld the Kovar alloy metal frame 120 on the substrate 110 . Specifically, the substrate 110 is an aluminum nitride substrate 110, the Kovar metal frame 120 is made of Mo-Ni-Cu alloy, and the aluminum nitride substrate 110 and the Kovar metal frame 120 are welded under vacuum and high temperature conditions. Ag70-Cu28-Ti2 active solder can be used. The size of the outer edge of the Kovar metal frame 120 is smaller than the size of the substrate 110 .

Before welding, grind the welding surface of the aluminum nitride substrate 110 with sandpaper to make the mortgaged surface smooth, then clean it with alcohol, put it in acetone solution and use ultrasonic cleaning for about 15 minutes to remove oil stains on the welded surface. Before using Ag70-Cu28-Ti2 active solder, remove the oxide layer on the surface, then put it into acetone solution for ultrasonic cleaning, and finally perform welding connection in a vacuum furnace with a vacuum degree better than 1.0ⅹ10 ^-3 Pa.

In this specific embodiment, the welding temperature is 1150K, the heating rate is 10° C./min, and the temperature is kept at 1000K and 1150K for 10 minutes respectively.

Step 2, welding a conductive layer on the Kovar alloy metal frame 120, the material of the conductive layer is selected from any one of metals, conductive compounds and polymer materials mixed with conductive substances, and the conductive layer can be a single-layer conductive layer Or a conductive layer formed alternately by multiple conductive layers and insulating layers. The conductive layer can not only be used to arrange circuits, but also can be used to reflect the light emitted by the LED chip to become a reflective layer.

Step 3, fixing the LED chip on the conductive layer on the upper surface by welding.

Step 4: Install a glass substrate 200 above the LED chip, and cover the outer periphery of the glass substrate with a protective cover, so that the packaging of the LED lamp bead is completed.

Specifically, the glass substrate 200 and a plurality of pixels vertically distributed on the glass substrate 200, each pixel includes a plurality of sub-pixel microcavities. In this embodiment, each pixel includes three sub-pixel microcavities: a red sub-pixel microcavity 201 , a green sub-pixel microcavity 202 and a blue sub-pixel microcavity 203 . Each sub-pixel microcavity is in the shape of a semi-cylindrical and semicircular in cross-section. In this way, the path of the excited light in the microcavity is the same, and the resonance spectrum generated is also the same. Therefore, it can be seen from all angles There will be no color deviation. The sub-pixel microcavity is arranged on the glass substrate, and an opaque anode layer 210 (such as Ag), a barrier layer 220 (such as Ag20), a hole transport layer 230 (NPB), and a light emitting layer are sequentially stacked from the glass substrate 200 upwards. Layer 240 (Alg3), electron transport layer 250 (Al/LiF) and semi-transparent cathode layer 260 (eg Ag). The opaque anode layer 210 is arc-shaped on the glass substrate, and the other layers are sequentially stacked fan-shaped layers, both ends are located on the glass substrate 200, and each layer has the same curvature. During fabrication, a grayscale mask is used to create the shape of each layer of film.

Step 5. Using laser cutting, the LED lamp beads are cut off from the sheet-like substrate, and divided into individual LED lamp beads.

The beneficial effects of the present invention are as follows: 1. The purpose of the Kovar alloy metal frame being smaller than the base plate is to facilitate mass production of the structure. Cut from the substrate, the cutting position is the place where the aluminum nitride is larger than the Kovar metal frame;

2. Through the above packaging structure, the LED can dissipate heat quickly, resist UV radiation, high temperature and yellowing;

3. Make the path of the excited light consistent, and there is no or very little chromatic aberration from all angles;

4. The conductive layer can not only be used to arrange the circuit, but also can be used to reflect the light emitted by the LED chip to become a reflective layer;

5. By adopting a concave-convex structure for the protective cover, the roughening of the surface of the LED package is effectively and simply realized, thereby improving the luminous efficiency of the high-efficiency LED.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "inner", "upper", "middle", "side", "upper" and so on is based on the orientation or positional relationship shown in the drawings , are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred unit or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "fixation" and other terms should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection, it can be a direct connection, it can also be an indirect connection through an intermediary, it can be an internal communication between two elements or an interaction relationship between two elements, unless otherwise clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A LED package structure, comprising a package body, characterized in that the package body comprises: Substrate; A kovar alloy metal frame is arranged above the substrate, and the size of the outer edge of the kovar alloy metal frame is smaller than the size of the substrate; The Kovar alloy metal frame is quadrilateral, and a conductive layer is arranged on the Kovar alloy metal frame, and a crystal-bonding area is arranged on the conductive layer; The crystal-bonding area is used to install LED chips; A glass substrate is installed on the crystal-bonding area, which includes a glass substrate and a plurality of pixels vertically distributed on the glass substrate, each pixel includes a plurality of sub-pixel microcavities, and the outer periphery of the glass substrate is covered with There is a protective cover, and the outer surface of the protective cover is a concave-convex structure; and An edge filter and a diffuser are also included in the package body, and the diffuser is used for receiving light reflected from the edge filter. 2. The LED packaging structure according to claim 1, wherein the substrate is an aluminum nitride substrate with metal lines. 3 . The LED packaging structure according to claim 1 , wherein the Kovar metal frame is made of Mo—Ni—Cu alloy, and the Kovar metal frame is connected to the substrate by welding. 4 . 4. The LED packaging structure according to claim 1, wherein the LED chip is soldered to the die-bonding area. 5. The LED packaging structure according to claim 1, wherein the material of the conductive layer is selected from any one of metals, conductive compounds and polymer materials mixed with conductive substances, and the conductive layer is: single conductive layer or A conductive layer formed alternately by multiple conductive layers and insulating layers. 6 . The LED packaging structure according to claim 1 , wherein the concave-convex structure is a microstructure, and the order of magnitude of the microstructure is nanoscale. 7. The LED packaging structure according to claim 1, wherein the sub-pixel microcavity is arranged on the glass substrate, and an opaque anode layer and a hole transport layer are sequentially laminated from the glass substrate upwards , a light emitting layer, an electron transport layer and a semitransparent cathode layer, each of which has the same curvature on the top surface away from the glass substrate. 8. A LED packaging method, characterized in that, comprising the steps of: Step 1. Welding metal lines on a sheet substrate, and welding the Kovar alloy metal frame on the substrate; Step 2, welding a conductive layer on the Kovar metal frame; Step 3, fixing the LED chip on the conductive layer on the upper surface by welding; Step 4. Install a glass substrate above the LED chip, and set a protective cover on the periphery of the glass substrate, so that the packaging of the LED lamp bead is completed; Step 5. Using laser cutting, the LED lamp beads are cut off from the sheet-like substrate, and divided into individual LED lamp beads. 9. The LED packaging method according to claim 8, wherein the substrate is an aluminum nitride substrate, the Kovar metal frame is made of Mo-Ni-Cu alloy, and the aluminum nitride substrate and Kovar alloys are welded under vacuum and high temperature conditions, and the solder can be Ag70-Cu28-Ti2 active solder. 10. The LED packaging method according to claim 8, wherein the size of the outer edge of the Kovar metal frame is smaller than the size of the substrate.