CN102468400B - LED packaging structure and manufacturing method thereof - Google Patents

Abstract

The invention discloses an LED packaging structure and a manufacturing method thereof, wherein the structure comprises a substrate, an LED chip arranged on the substrate and a lens packaged on the LED chip; and a light-transmitting film is formed between the LED chip and the lens, and the refractive index of the light-transmitting film is between that of the lens and that of the LED chip. The manufacturing method is that the light-transmitting film is firstly formed on the inner surface of the lens opposite to the LED chip, and the lens is hot-pressed when in packaging and forming so that the light-transmitting film is covered on the LED chip. The LED light source can improve the external light-taking rate, reduce the electric power and the heat generated by the LED chip, prolong the service life and achieve the practical purposes of high brightness, low heat release and more power saving.

Description

LED packaging structure and manufacturing method thereof

technical field

The invention relates to a technology for packaging LED chips, in particular to an LED packaging structure and a manufacturing method thereof.

Background technique

At present, light-emitting diodes (LEDs) have been widely used in various lighting or light-emitting displays and other occasions. In the past, the packaging process of the lens had to be carried out on the LED chip. However, since the refractive index of the material used for the general LED chip (about 2.45-3.4) is higher than the refractive index of the material used for the packaging material or the lens (usually plastic material, the refractive index is about 1.4-1.5), so, In the case of a large refractive index drop, the total reflectance of the light passing through the packaging material or the lens is also large, resulting in a low lumen (Lumen) of the luminous flux, and the luminous electric power of the LED chip must be increased to achieve the predetermined value. However, it is easy to cause the heat generated by the LED chip to increase and reduce its service life.

Contents of the invention

The main purpose of the present invention is to provide an LED packaging structure, which can increase the external light extraction rate, reduce the electric power and the heat generated by the LED chip, prolong the service life, and achieve the practical purposes of high brightness, low heat release and more power saving.

Another object of the present invention is to provide a method for manufacturing an LED package, which can safely and reliably arrange a light-transmitting film between the LED chip and the lens.

In order to achieve the above object, the present invention provides an LED packaging structure, comprising: a substrate, an LED chip disposed on the substrate, and a lens packaged on the LED chip; wherein, a light-transmitting film is formed between the LED chip and the lens, and The refractive index of the transparent film is between that of the lens and that of the LED chip.

Two conductive layers serving as positive and negative electrodes are arranged on the substrate, and the LED chip is arranged between the two conductive layers, and is electrically connected to the two conductive layers through two bonding wires respectively.

Adhesives are provided on the two welding wires as fixing wires.

Silver glue is coated between the substrate and the LED chip for fixing.

The lens is composed of a light-transmitting cover and an encapsulation layer.

The material of the transparent film is titanium dioxide, silicon dioxide or aluminum oxide.

The light-transmitting film is formed by laminating two or more materials with different refractive indices, and the refractive indices of each layer are arranged in decreasing order according to the refractive indices from the LED chip to the lens.

In order to achieve the above object, the present invention also provides a LED encapsulation manufacturing method, comprising the following steps:

a) preparing a substrate with an LED chip and a light-transmitting cover for packaging on the LED chip;

b) forming a light-transmitting film on the inner surface of the light-transmitting cover opposite to the LED chip, the refractive index of the light-transmitting film being between that of the light-transmitting cover and the LED chip;

c) placing the light-transmitting cover on the LED chip, and when packaging the LED chip, applying heat and pressure to the light-transmitting cover so that the light-transmitting film covers the LED chip.

The material selected for the transparent film in the step b) is titanium dioxide, silicon dioxide or aluminum oxide.

In the step b), the light-transmitting film is formed on the light-transmitting cover by vapor deposition.

The vapor deposition method refers to ion vapor deposition.

The light-transmitting film in the step b) is formed by stacking two or more materials with different refractive indices, and the refractive index of each layer matches the refractive index of the LED chip to the light-transmitting cover. Arranged in decreasing order.

Compared with the prior art, the LED packaging structure of the present invention adds at least one layer of light-transmitting film in the lens that encapsulates the LED chip, and the refractive index of the light-transmitting film is between the refractive index of the LED chip and the lens. In this way, the external light extraction rate can be improved, the electric power and the heat generated by the LED chip can be reduced, the service life of the LED chip can be extended, and the practical purpose of high brightness, low heat dissipation and power saving can be achieved. In addition, since the crystal lattice mismatch or the difference in thermal expansion coefficient may cause problems such as cracking and damage to the epitaxial wafer, it is impossible to directly coat the aforementioned light-transmitting film on the LED chip. Therefore, the method for manufacturing an LED package provided by the invention uses The lens serves as a medium to achieve the purpose of disposing the light-transmitting film between the LED chip and the lens.

Description of drawings

Fig. 1 is the flow chart of the steps of the preparation method of the present invention;

2 is a schematic top view of the substrate of the present invention;

3 is a schematic structural view of the substrate and the light-transmitting cover before assembly of the present invention;

Fig. 4 is a schematic diagram of the combination of the light-transmitting cover of the present invention placed on the substrate;

Fig. 5 is the schematic cross-sectional view of the combination of the present invention;

FIG. 6 is a schematic cross-sectional view of another embodiment of the present invention.

Explanation of reference signs

Substrate 1

Conductive layer 10 silver glue 11

LED chip 2

Soldering wire 20 Adhesive 21

lens 3

Light-transmitting cover 30 encapsulation layer 31

Transparent film 4

The first layer 40 The second layer 41

third floor 42

Detailed ways

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the accompanying drawings are provided for reference and illustration only, and are not intended to limit the present invention.

The present invention provides an LED packaging structure and a manufacturing method thereof. At least one layer of light-transmitting film is added to the lens encapsulating the LED chip, and the refractive index of the light-transmitting film is between the refractive index of the LED chip and the refractive index of the lens. In this way, the lumen can be increased and the heat generated by the LED chip can be reduced to prolong its service life. The manufacturing method of LED encapsulation of the present invention is as shown in Figure 1:

First, please refer to step S1 of FIG. 1, and as shown in FIG. 2 and FIG. 3: prepare the substrate 1 with the LED chip 2, and the light-transmitting cover 30 for packaging on the LED chip 2; wherein, as shown in FIG. 2, the substrate 1 with the LED chip 2 is provided with two conductive layers 10 as positive and negative electrodes. 20 are electrically connected to the two conductive layers 10 respectively, and then an adhesive 21 such as silica gel is applied on the two bonding wires 20 as a fixing wire, so as to avoid problems such as breaking the two bonding wires 20 in subsequent processes. In addition, silver glue 11 can be further coated between the LED chip 2 and the substrate 1 for fixing.

Next, please refer to step S2 of FIG. 1 , and as shown in FIG. 3 : a light-transmitting film 4 is formed on the inner surface of the above-mentioned light-transmitting cover 30 opposite to the LED chip 2 , and the refraction of the light-transmitting film 4 The index (n) is between the refractive index of the light-transmitting cover 30 and the LED chip 2; that is, the refractive index of the LED chip 2 (n _chip )>the refractive index (n) of the light-transmitting film 4>the light-transmitting seal The refractive index of the cover 30 (n _cover ). For example: if the refractive index (n _chip ) of the LED chip 2 is 2.45-3.4, and the refractive index (n _cover ) of the transparent cover 30 is 1.4-1.5, then the refractive index (n) of the transparent film 4 It can be between 1.4-3.4. Therefore, the material that can be selected can be titanium dioxide (TiO ₂ ), silicon dioxide (SiO ₂ ) or aluminum oxide (Al ₂ O ₃ ), etc., and can be obtained by evaporation ( The above-mentioned material is formed on the light-transmitting cover 30 by means such as ion evaporation) to form the light-transmitting film 4 .

Then, please refer to step S3 in FIG. 1 , and in conjunction with FIG. 4 and FIG. 5 : put the above-mentioned light-transmitting cover 30 on the LED chip 2, and when packaging the LED chip 2, the light-transmitting cover 30 The cover 30 applies heat and pressure to cover the light-transmitting film 4 on the LED chip 2 . Wherein, the encapsulation layer 31 can be formed on the light-transmitting cover 30 by in-mold injection, and since the encapsulation layer 31 and the light-transmitting cover 30 can be made of the same material, they will be fused together during the process of hot pressing, so the The light-transmitting cover 30 and the encapsulation layer 31 constitute the lens 3, and the steps of the manufacturing method of the present invention are completed.

Therefore, as shown in FIG. 5, the LED packaging structure of the present invention includes the aforementioned substrate 1, the aforementioned LED chip 2 disposed on the substrate 1, and the aforementioned lens 3 packaged on the LED chip 2, and the LED chip 2 and The above-mentioned light-transmitting film 4 is formed between the lenses 3, and the refractive index (n) of the light-transmitting film 4 is between the refractive index (n _lens ) of the lens 3 and the refractive index (n _chip ) of the LED chip 2 between; that is, the refractive index of the LED chip 2 (n _chip )>the refractive index of the transparent film 4 (n)>the refractive index of the lens 3 (n _lens ).

In addition, as shown in FIG. 6, the light-transmitting film 4 can also be formed by stacking two or more materials with different refractive indices; in this embodiment, the first layer 40, the second layer 41 and the second layer It is composed of three layers 42, and the refractive index of each layer is arranged in a gradually decreasing order according to the refractive index from the LED chip 2 to the lens 3 (or the light-transmitting cover 30). For example, the refractive index (n ₁ ) of the first layer 40 is 2.2 , the refractive index (n ₂ ) of the second layer 41 is 1.95, and the refractive index (n ₃ ) of the third layer 42 is 1.7, which can further reduce the total reflectance generated when the light passes through the lens 3, so as to improve The purpose of lumens, and at the same time reduce the heat generated by the LED chip to prolong the service life and so on.

Therefore, the LED packaging structure and the manufacturing method thereof of the present invention can be obtained through the above steps.

The foregoing are only preferred embodiments of the present invention, and are not intended to limit the implementation scope of the present invention. That is, all equivalent changes and modifications made according to the claims of the present invention are covered by the patent scope of the present invention.

Claims (5)

1. A kind of LED encapsulation structure, it is characterized in that, comprising: Substrate; an LED chip disposed on the substrate; and The lens is packaged on the LED chip. The lens is composed of a light-transmitting cover and an encapsulation layer that are fused together by heat and pressure of the same material, and the light-transmitting cover is placed on the LED chip and placed on the light-transmitting forming the encapsulation layer on the cover; Wherein, a light-transmitting film is formed between the LED chip and the lens, the light-transmitting film is located on the inner surface of the lens opposite to the LED chip, and the refractive index of the light-transmitting film is between the refractive index of the lens and the Between the refractive index of the LED chip, the light-transmitting film is formed by laminating two or more materials with different refractive indices, and the refractive index of each layer matches the refractive index of the LED chip to the lens in a gradually decreasing arrangement. . 2. The LED packaging structure according to claim 1, wherein two conductive layers as positive and negative poles are arranged on the substrate, the LED chip is arranged between the two conductive layers, and passes through the two conductive layers. The root welding wires are respectively electrically connected to the two conductive layers. 3. The LED packaging structure according to claim 2, wherein an adhesive is provided on the two bonding wires as a fixing wire. 4 . The LED packaging structure according to claim 1 , wherein silver glue is coated between the substrate and the LED chip as fixation. 5. The LED packaging structure according to claim 1, wherein the material of the light-transmitting film is titanium dioxide, silicon dioxide or aluminum oxide.