CN102694108A - High-power LED packaging structure - Google Patents

Abstract

The invention provides a high-power LED packaging structure, which includes a reflective cup and an integrated packaging substrate. The reflective cup is a groove opened on the surface of the integrated packaging substrate. The upper end of the reflective cup is provided with a lens. A bonding layer, an LED chip, a dispensing layer, and a phosphor layer are sequentially arranged in the cavity of the cavity, and electrodes for connecting the LED chip and the driving circuit are arranged on the integrated packaging substrate. The LED packaging structure of the present invention uses the integrated packaging to effectively It solves the heat dissipation bottleneck in traditional LEDs; the layered dispensing layer keeps the LED chip away from the phosphor layer, reduces the reabsorption of light by the LED chip in the traditional packaging structure, improves the light output rate, and improves the light distribution performance. The LED packaging structure is not only simple in structure, but also cancels the bracket, aluminum substrate and heat sink in the traditional packaging, reduces process steps and costs, and is convenient for industrial production.

Description

A high-power LED packaging structure

technical field

The invention relates to an LED packaging structure, in particular to a high-power LED packaging structure.

Background technique

LED is a kind of diode that uses semiconductor PN junction to emit light. It has a broad market in the fields of indicator lights, signal lights, backlights, and landscape lighting. LED has the advantages of high luminous efficiency, low power consumption, long service life, strong safety and reliability, and environmental protection, making it the fourth-generation lighting source to replace traditional incandescent lamps, fluorescent lamps, and high-pressure gas discharge lamps. The packaging structure of the LED will directly affect the core issues such as the junction temperature and light distribution performance of the LED, so the scientific light distribution performance is a breakthrough to improve the heat dissipation and light distribution of the LED.

The packaging of traditional high-power LEDs is to bond the LED chip to the bracket, and then weld the bracket to the aluminum substrate to complete the circuit connection and mechanical support protection; due to the heat dissipation bottleneck caused by the structure of the bracket and the aluminum substrate, the high-power LED Junction temperature is too high, unstable, easy to cause light decay, color decay and so on. The traditional fluorescent layer is directly dot powder on the chip, then add lens and fill encapsulation glue. This structure is difficult to control the shape and uniformity of the phosphor, and it is easy to cause problems such as uneven distribution of light intensity and uneven color distribution. Moreover, the distance between the phosphor layer and the LED chip is too close, which intensifies the reabsorption of the LED chip and reduces the external quantum efficiency.

Contents of the invention

The object of the present invention is to provide a high-power LED packaging structure, which simplifies the packaging process, reduces the packaging cost, and has the characteristics of good heat dissipation effect, high light extraction rate and excellent light distribution performance.

In order to achieve the above object, the present invention adopts the following technical solutions:

It includes a reflective cup and an integrated packaging substrate, the reflective cup is a groove opened on the surface of the integrated packaging substrate, a lens is arranged on the upper end of the reflective cup, and a bonding layer, an LED The chip, the dispensing layer, the phosphor layer, and the integrated packaging substrate are provided with electrodes for connecting the LED chip and the driving circuit.

The integrated packaging substrate is an aluminum plate or a copper plate whose surface has been oxidized and insulated, and enameled wires for connecting the drive circuit are welded on the electrodes.

One end of the electrode is arranged at the bottom of the reflective cup, and the other end extends out of the reflective cup.

The electrodes are silver-plated electrodes or gold-plated electrodes.

The material of the bonding layer is silver glue or insulating glue.

The material of the dispensing layer is silica gel or epoxy resin.

The phosphor layer is solid hemispherical.

Encapsulation glue is filled between the phosphor layer and the lens, and the lens is fixed on the integrated packaging substrate through the encapsulation glue.

The high-power LED packaging structure of the present invention directly fixes the LED chip on the integrated packaging substrate through the bonding layer, which solves the heat dissipation bottleneck of the bracket and the aluminum substrate in the traditional LED structure, and achieves the purpose of good heat dissipation; The packaging structure of high-power LED adopts to separate the dispensing layer and the phosphor layer, so that the phosphor layer is far away from the LED chip, which reduces the reabsorption of light by the LED chip, improves the light output rate, and improves the light distribution performance; The high-power LED packaging structure can directly integrate the phosphor layer into the lens, which simplifies the production of the hemispherical phosphor layer. At the same time, the phosphor layer is hemispherical, which can better match the Luangberian distribution of the LED chip light. Not only is the structure simple, but also the cost is low, which is beneficial to mass production and facilitates industrialized production.

Description of drawings

Fig. 1 is the structural representation of high-power LED packaging structure of the present invention;

Fig. 2 is a structural sectional view of the high-power LED packaging structure of the present invention;

Figure 3 is a schematic diagram of thermal resistance testing;

In the figure: lens 1, phosphor layer 2, reflective cup 3, LED chip 4, integrated packaging substrate 5, bonding layer 6, glue dispensing layer 7, electrode 8, packaging glue 9, enameled wire 10.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

1 and 2, the present invention includes a reflective cup 3 and an integrated packaging substrate 5, the reflective cup 3 is a groove opened on the surface of the integrated packaging substrate 5, the upper end of the reflective cup 3 is provided with a lens 1, the lens 1 and the cavity formed by the reflector 3 are sequentially provided with a bonding layer 6, an LED chip 4, a dispensing layer 7 and a phosphor layer 2, and an electrode 8 for connecting the LED chip 4 and the driving circuit is provided on the integrated package substrate 5 .

The integrated packaging substrate 5 is an aluminum or copper plate whose surface has been oxidized and insulated. The electrode 8 is welded with an enameled wire 10 for connecting the drive circuit. One end of the electrode 8 is arranged at the bottom of the reflective cup 3, and the other end extends to the reflective cup 3. Outside the cup 3, the electrodes 8 are silver-plated electrodes or gold-plated electrodes.

The material of the bonding layer 6 is silver glue or insulating glue, and the material of the dispensing layer 7 is silica gel or epoxy resin. The phosphor layer 2 is solid hemispherical, and the gap between the phosphor layer 2 and the lens 1 is filled with encapsulation glue 9 , and the lens 1 is fixed on the integrated encapsulation substrate 5 through the encapsulation glue 9 .

Example

A high-power LED packaging structure adopts an integrated packaging structure, the power of the LED chip used is 1-3W, the thickness of the phosphor layer is 1-3mm, and the height of the dispensing layer is 2-4mm. During preparation, the reflective cup is first manufactured on the metal aluminum plate, and then the surface of the metal aluminum plate is insulated, and then electrodes are fixed on the reflective cup to complete the integrated packaging substrate. Then carry out the traditional packaging steps for the LED chip, crystal expansion-spine-short baking, so that the LED chip is solidified in the reflective cup on the integrated packaging substrate through the bonding layer; the connection between the electrode and the chip is completed by punching gold wires; manufacturing After the hemispherical phosphor layer, dispensing, dispensing, and long baking are carried out on the LED chip, and finally the lens and the metal aluminum plate are fixed by filling the encapsulation glue in the lens (the lens has pinholes, and the encapsulation glue is injected into the phosphor in the lens layer).

This embodiment is based on an integrated packaged LED, which can achieve better light intensity distribution, higher light extraction rate, and better heat dissipation. The hemispherical phosphor layer is more in line with the Langerb distribution of the LED chip’s light emission. The dispensing layer can keep the phosphor layer away from the LED chip and reduce the reabsorption of the LED chip. The method is simple, low in cost and beneficial to industrialized production.

Referring to Figure 3, use the following method to measure the composite thermal resistance of the oxide film and pure aluminum, that is, the thermal resistance of the integrated package substrate. Cover the upper part of the resistor with adhesive tape to greatly reduce the upward transfer of heat. Compared with the downward transfer of heat, The upward heat transfer is basically negligible. In addition, when measuring the data, the thermocouple is installed near the distance of 1 cm from the resistor, and it is measured after thermal equilibrium, that is, after the resistor is energized for 2 hours, the temperature of the two surfaces is uniform and remains unchanged, which can accurately reflect the temperature of the two surfaces . Then the thermal power input to the aluminum substrate is approximately the electrical power consumed by the resistor.

According to the calculation formula of thermal resistance:

$\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; P</span>}}\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="T"\; filenames="HDA00001699054300012.png"\; state="\{\{state\}\}">T</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; UI</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Calculate the composite thermal resistance of the aluminum substrate. Among them, T1 represents the temperature at temperature measuring point 1, T2 represents the temperature at temperature measuring point 2, U and I represent the voltage and current at both ends of the resistor, and P represents the thermal power of the input resistor.

The composite thermal resistance is 1°C/W, and the aluminum oxide film formed on the aluminum surface by anodic oxidation has a lower thermal conductivity than the aluminum oxide crystal due to the irregular crystal state, generally about 2W/m·K, but it is still much higher than the existing The epoxy resin in the metal-based copper clad laminate is 0.2-0.8W/m K, and the thickness of the aluminum oxide film obtained by anodic oxidation can be much smaller than the epoxy resin. Therefore, the thermal resistance of the integrated package substrate is significantly better than the existing metal-based copper-clad laminates.

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (8)

1. A high-power LED packaging structure, characterized in that it includes a reflective cup (3) and an integrated packaging substrate (5), and the reflective cup (3) is a concave hole set on the surface of the integrated packaging substrate (5). groove, the upper end of the reflective cup (3) is provided with a lens (1), and the cavity formed by the lens (1) and the reflective cup (3) is sequentially provided with a bonding layer (6), an LED chip (4), and a dispensing layer ( 7) and the phosphor layer (2), the integrated packaging substrate (5) is provided with electrodes (8) for connecting the LED chip (4) and the driving circuit. 2. A high-power LED package structure according to claim 1, characterized in that: the integrated package substrate (5) is an aluminum plate or copper plate whose surface has been oxidized and insulated, and electrodes (8) are welded to connect the drive The enameled wire (10) of the circuit. 3. A high-power LED packaging structure according to claim 2, characterized in that: one end of the electrode (8) is arranged at the bottom of the reflective cup (3), and the other end extends out of the reflective cup (3). 4. A high-power LED packaging structure according to claim 2, characterized in that: the electrodes (8) are silver-plated electrodes or gold-plated electrodes. 5. A high-power LED packaging structure according to claim 1, characterized in that: the bonding layer (6) is made of silver glue or insulating glue. 6. A high-power LED packaging structure according to claim 1, characterized in that: the material of the dispensing layer (7) is silica gel or epoxy resin. 7. A high-power LED packaging structure according to claim 1, characterized in that: the phosphor layer (2) is a solid hemispherical shape. 8. A high-power LED packaging structure according to claim 1, characterized in that: the phosphor layer (2) and the lens (1) are filled with encapsulation glue (9), and the lens (1) passes through the encapsulation glue ( 9) Fixed on the integrated packaging substrate (5).

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