CN204118067U - Directly be packaged in the LED chip encapsulation architecture of radiator - Google Patents

Abstract

The utility model discloses a single or multiple LED chip packaging structure directly packaged in a heat sink, relates to the packaging technology of LEDs, in particular relates to the packaging technology of LED chips directly packaged in a heat sink, and is used for greatly improving LED chips and arrays. The temperature management solves the heat dissipation problem of high-brightness LED lighting devices and display equipment, thereby improving the lumen output of LEDs and prolonging their lifespan. At the same time, it simplifies the LED packaging process and reduces packaging costs. In this technical solution, the heat sink is directly used as the substrate, and the LED chip is directly fixed on the surface of the heat sink by a heat-conducting die-bonding glue, and each LED packaging unit is electrically connected to form a common light-emitting array. LED chips and arrays are wrapped in encapsulants to adjust color temperature, improve luminous efficiency and protect the packaging structure of LEDs.

Description

LED chip package structure directly packaged in heat sink

technical field

The utility model relates to LED packaging technology, in particular to the packaging technology in which LED chips and arrays are directly packaged in a radiator.

Background technique

In recent years, the technology of solid-state LED (Light Emitting Diode, Light Emitting Diode) light source has developed rapidly, and its application is becoming more and more extensive. Compared with traditional incandescent lamps and gas discharge lamps, LED light sources have obvious advantages such as high luminous efficiency, long life, fast start-up, and good shock resistance, and are increasingly used in various lighting devices and display devices. However, the LED light source Thermal issues have been plaguing the industry. In order to achieve the theoretically long life of LEDs and maintain luminous efficacy, the PN junction temperature usually needs to be controlled below 85°C. Excessively high junction temperature is the main reason for the premature failure of existing LED lighting products. Some studies have found that when the junction temperature If the surface temperature rises by 10°C, the luminous flux of the LED will decrease by 10%, and its life will also decrease by 50%. In practical applications, the lower the junction temperature of the LED, the better.

Existing LED lighting devices and display devices mostly use SMD chip packaging devices such as 3020, 3528, and 5050, which have problems such as high cleaning temperature, many particles, large volume, high cost, and easy glare. Relatively new COB (Chip on Board) and MCOB (Multi-Chips on Board) packaging technologies are to directly package LED chips on aluminum substrates, copper substrates, ceramic substrates or silicon substrates, and improve unit by reducing thermal resistance. The luminous intensity of the area, but the packaging substrates of COB and MCOB need to be connected with an independent heat sink, and the transition between the two interfaces inevitably leads to the generation of additional thermal resistance, thus reducing the thermal conductivity and making it ineffective. Solving the problem of LED as a point heat source affects the life of the LED and the maintenance of light efficiency, and also limits the increase of the current of the LED chip and the increase of the power of the entire LED array.

Utility model content

Aiming at the deficiencies in heat dissipation of the existing packaging structure, the utility model proposes a packaging technology in which the LED chip is directly packaged in the heat sink. This technology directly uses the heat sink as the substrate, and removes the aluminum used in the conventional COB and MCOB packaging. substrate, copper substrate, ceramic substrate or silicon substrate, so compared with existing SMD, COB and MCOB packaging technologies, the thermal resistance can be reduced to a lower level.

Specifically, the packaging solution includes a heat sink and at least one LED chip, and the single or multiple LED chips are directly fixed on the surface of the heat sink through a heat-conducting die-bonding adhesive.

The LED packaging structure is characterized in that the heat sink is made of one of metal materials with high thermal conductivity, inorganic non-metallic materials, polymer materials and composite materials, and the preferred materials are metals such as aluminum and copper or thermally conductive alloys; The heat dissipation part of the heat sink has no specific shape, but it can usually be processed into a sawtooth shape; the LED chip and the heat sink are bonded to each other through a layer of thermally conductive die-bonding adhesive; the area on the surface of the heat sink without LEDs is covered with an insulating layer, The insulating layer is covered with a conductive circuit layer; each LED chip unit is electrically connected to each other by gold wires, silver wires, aluminum wires or other conductive metal wires or alloy wires, and is electrically connected to the external drive power supply through the conductive circuit layer. Thus, a light emitting unit or an array is formed; the LED packaging unit and the array are potted in at least one layer of sealant.

The upper surface of the heat sink can be provided with at least one reflective cup. In some examples, the inner side of the reflective cup is coated with a metal reflective layer. The preferred reflective layer material is silver, and it can also be gold, copper, nickel, etc. with high reflectivity. Metal or other inorganic materials; LED chips are fixed on the bottom of the reflective cup by thermally conductive crystal-bonding glue.

The upper surface of the heat sink may also not be provided with a reflective cup, but is flat, and the LED chip is directly fixed on the plane of the heat sink by a heat-conducting crystal-bonding glue; The reflective layer is preferably made of silver, and may also be metals with high reflectivity such as gold, copper, nickel, or other inorganic materials.

The heat-conducting die-bonding adhesive requires high thermal conductivity, and is preferably silica gel, epoxy resin, silicone resin, insulating adhesive, conductive adhesive, resin adhesive, silver adhesive, or eutectic solder. The eutectic solder is preferably gold-tin (Au-Sn) alloy, silver-tin (Ag-Sn) alloy, copper-tin (Cu-Sn), solder paste or other high thermal conductivity alloy solder such as tin-silver-copper (Sn-Ag-Cu ), tin-gold-copper (Sn-Au-Cu) or tin-gold-silver (Sn-Au-Ag) alloys.

The sealant is a mixture of fluorescent powder and glue. The glue material has the characteristics of high light transmittance, high refractive index, good fluidity, and easy curing, and can be preferably silica gel, epoxy resin, silicone resin, resin glue, polyurethane, polycarbonate, polymethacrylate Grease or glass, and its cured form can be solid, gel, elastomer or resin. The sealant layer is enclosed by a fence, and the material of the fence is preferably silica gel, resin, plastic or glass.

The LED packaging unit can also have an independent sealant layer, the surface of which is lens-shaped or flat, to change the light beam characteristics and improve light efficiency.

The utility model further reduces the thermal resistance of the LED packaging device, is easier to control the temperature of the PN junction surface, and is beneficial to prolonging the service life of the LED lighting device and display equipment. Because heat dissipation is improved, LED lighting devices with the same power can use fewer LED chips and packaging units, thus reducing packaging costs while improving reliability, and is beneficial to the miniaturization of LED lighting modules, making the light emitting per unit area Strength is improved.

Description of drawings

FIG. 1 is a schematic diagram of the basic structure of the package architecture of the present invention and a cross-sectional view of the first embodiment.

FIG. 2 is a schematic cross-sectional view of a second embodiment of the package architecture of the present invention.

FIG. 3 is a schematic cross-sectional view of a third embodiment of the package architecture of the present invention.

FIG. 4 is a schematic cross-sectional view of a fourth embodiment of the package architecture of the present invention.

Detailed ways

The utility model proposes a package structure directly packaged in a radiator, including a radiator directly used as a substrate and with a reflective cup and an LED chip with a horizontal structure. The reflective cup can be coated with a reflective layer such as a silver layer , gold layer or nickel layer to increase light reflection, the double-electrode LED chip is placed at the bottom of the cup, and there is a layer of heat-conducting die-bonding glue between the LED chip and the bottom of the cup to fix the LED chip. The heat sink can also be without a reflective cup, and the LED chips are directly fixed on the surface of the heat sink.

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Fig. 1 is a schematic diagram of the basic structure and the first embodiment of the present invention, wherein the LED chip 10 has a normal horizontal structure. In this package structure, the heat sink 12 is directly used as the package substrate, and the shape of the heat dissipation part is not limited to the saw-tooth shape in the figure, and its material can be aluminum or copper, or other heat-conducting metals or alloys. The upper surface of the radiator is dug with single or multiple reflective cups 14, and the inside of each reflective cup can be plated with a silver layer to strengthen the emission of light, and can also be plated with gold, nickel and other metals with high reflectivity or other inorganic materials. The area on the surface of the heat sink that is not provided with a reflective cup is covered with an insulating layer 16 and a conductive circuit layer 18, and the two ends 20 and 22 of the conductive circuit layer are electrically connected to the positive pole and the negative pole of the output of the LED drive power supply respectively. The base of the LED chip is bonded to the bottom of the reflective cup through a heat-conducting crystal-bonding glue 24, and the heat-conducting crystal-bonding glue is preferably silica gel, epoxy resin, silicone resin, insulating glue, conductive glue, resin glue, silver glue, or eutectic solder. The positive electrode 26 and the negative electrode 28 of the upper part of the LED chip are electrically connected by gold wires, silver wires, aluminum wires or alloy wires 30 and pads 32 of the conductive layer to form a single LED light-emitting unit or an LED array that can emit light together; for For a large number of LED arrays, they can be divided into multiple groups, and the LED units in each group can be connected in series with each other, and each group can be connected in parallel. Further, as shown in the figure, a layer of heat-conducting sealant 34 is poured on the LED units and arrays to adjust the color temperature of light, improve light efficiency and protect LED chips. The sealant is surrounded by a fence 36, so that the surface of the sealant is planar, and the material of the fence can be silica gel, resin, plastic or glass. The sealant is a mixture of phosphor powder and glue. The preferred glue can be one of silicone, epoxy, silicone, resin glue, polyurethane, polycarbonate, polymethyl methacrylate or glass.

The example shown in FIG. 2 is similar to the example of FIG. 1 previously described. Similarly, the heat sink 40 is used as the packaging substrate and the horizontal LED chip 42 is directly fixed on the bottom of the reflective cup by the heat-conducting die-bonding glue 44 . The inner side of the reflective cup can be coated with a metal reflective layer. The difference is that in this example, each reflective cup LED unit is covered with an independent sealant layer 46 , and the sealant layer is in the shape of a lens to protect each package unit and adjust the characteristics of the outgoing light beam and improve light efficiency. The sealant layer can also be made into other shapes such as flat according to actual optical requirements. The heat-conducting die-bonding adhesive and sealing material used are the same as those used in the aforementioned example in FIG. 1 .

In order to reduce the amount of phosphor used and reduce the operating temperature of the phosphor, the phosphor can be isolated from the LED die as a point heat source. Figure 3 shows an example of this application. Similar to the example shown in Figure 1, the heat sink 50 is directly used as the substrate, and the horizontal LED chip 52 is directly placed at the bottom of the reflective cup, with a layer of heat-conducting die-bonding glue 54 between the LED chip and the bottom of the reflective cup. bonding. The inside of the reflective cup can be coated with a metal reflective layer, and the material of the heat-conducting die-bonding adhesive is the same as the die-bonding adhesive selected in the example in Figure 1. The LED crystal grains are encapsulated in the reflective cup by a sealant 56 , and above the sealant 56 is a layer of common fluorescent powder glue layer 58 . The sealing material is preferably silica gel, epoxy resin, silicone resin, resin glue, polyurethane, polycarbonate, polymethyl methacrylate or glass, and the phosphor powder glue may contain phosphor powder and water-absorbing resin. Similarly, similar to the example shown in FIG. 2 , each reflective cup LED unit can be covered with independent phosphor glue and made into a lens or flat shape.

What Fig. 4 shows is the fourth example of the present utility model. In this example, the surface of the heat sink 60 is not provided with a reflective cup, but is flat, and a metal reflective layer can be plated on and around the position of the LED, and the LED chip 62 is directly fixed on the heat sink by a heat-conducting die-bonding glue 64. on the surface. Each LED chip is connected by gold wire, silver wire, aluminum wire or alloy wire 66 to form an electrical connection. All LED chips are encapsulated in the encapsulant 68 , and the encapsulant is enclosed by a fence 70 . The materials of the metal reflective layer, heat-conducting die-bonding adhesive, sealant, and fence in this example are the same as those used in the example in FIG. 1 .

The novel packaging architecture described in the utility model removes the aluminum substrate, copper substrate, ceramic substrate or silicon substrate used in COB and MCOB packaging, and the bonding layer between the substrate and the heat sink, thereby reducing the additional thermal resistance, which is very It is beneficial to the heat dissipation of the point heat source LED chip, thus effectively maintaining the luminous efficiency of the LED light source, improving its reliability and prolonging the service life of the LED lighting and display devices.

The above-mentioned embodiments and accompanying drawings are used to illustrate the content of the present utility model, but are not limited to the product structure and form of the present utility model, and any person of ordinary skill in the art may make appropriate changes and modifications to it, and these changes and modifications All can not be regarded as departing from the scope of the patent of the utility model.

Claims (8)

1. be directly packaged in a LED chip encapsulation architecture for radiator, comprise radiator and at least one LED chip, it is characterized in that: this LED chip is directly bondd by heat-conductive solid crystal glue and is fixed on this spreader surface;

Described encapsulation architecture also comprises:

One insulating barrier, this insulating barrier is positioned at the region that this spreader surface does not install the chip of this LED; And

One conductive circuit layer, this conductive circuit layer is positioned at above this insulating barrier.

2. be directly packaged in as claimed in claim 1 the LED chip encapsulation architecture of radiator, it is characterized in that: this radiator material be metal material, Inorganic Non-metallic Materials, macromolecular material and composite material one of them make.

3. be directly packaged in the LED chip encapsulation architecture of radiator as claimed in claim 1, it is characterized in that: this LED chip exists electric connection each other.

4. be directly packaged in as claimed in claim 1 the LED chip encapsulation architecture of radiator, it is characterized in that: this heat-conductive solid crystal glue be silica gel, epoxy resin, silicones, insulating cement, conducting resinl, resin glue, elargol and eutectic solder one of them.

5. the LED chip encapsulation architecture being directly packaged in radiator as described in any one of claim 1-4, is characterized in that: this LED chips all are covered by least one deck sealing, and this adhesive layer is surrounded by fence.

6. the LED chip encapsulation architecture being directly packaged in radiator as described in any one of claim 1-4, is characterized in that: this LED chip is covered by independently sealing separately.

7. the LED chip encapsulation architecture being directly packaged in radiator as described in any one of claim 1-4, is characterized in that: the upper surface of this radiator is provided with at least one reflector, and this LED chip single or multiple is fixed at the bottom of this reflector by this heat-conductive solid crystal glue.

8. be directly packaged in the LED chip encapsulation architecture of radiator as claimed in claim 7, it is characterized in that: the inner surface of this reflector is coated with layer of metal reflector.