CN104037302B - LED (light-emitting diode) package assembly - Google Patents

Abstract

The present invention provides an LED package assembly, comprising: a flexible substrate with a circuit layer formed therein; a reflective layer mounted on the first side of the flexible substrate; an LED chip mounted on the flexible substrate, the The electrodes of the LED chip are electrically connected to the circuit layer through the reflective layer; and the protective layer is arranged on the second side of the flexible substrate. The LED packaging assembly according to the present invention has a flexible substrate, which expands its application range. In addition, the substrate of the LED packaging assembly has a simple structure, so that the formed thermal resistance is relatively low. In addition, the preparation of the LED packaging component is simple and the production cost is low.

Description

A kind of LED package assembly

technical field

The present invention relates to a light emitting diode (LED), in particular to an LED packaging assembly, especially a white LED packaging assembly.

Background technique

LED can convert electrical energy into light energy with high efficiency, and has the characteristics of low current consumption and long service life. Therefore, LEDs can be applied not only to display devices, but also to lighting fixtures. In recent years, LED has been widely used in various lighting fields as a new type of light source.

At present, for traditional LED packaging devices, LED chips are generally used in conjunction with mounting brackets, and then they are fixed together on an aluminum substrate. Afterwards, the aluminum substrate is thermally connected to the heat sink. However, this preparation method has the disadvantage of high thermal resistance. In order to reduce thermal resistance, another mainstream packaging structure is to directly match the LED chip with the substrate, and then thermally connect with the heat sink. In this case, the LED chips can be placed in the grooves provided on the surface of the substrate, and then connected by solder, such as solder paste or the like. The solder paste can be formed flush with the surface of the substrate, or can be formed as an arc surface protruding from the surface of the substrate.

Patent document CN202487662U discloses an LED packaging structure, which includes a packaging substrate, an LED chip disposed on the packaging substrate, and packaging glue covering the packaging substrate and the LED chip. Wherein, a hemispherical lens is also provided between the LED chip and the packaging glue. Here, the packaging substrate is generally a hard substrate, such as a metal or ceramic substrate.

Patent document CN202474038U discloses an LED bracket type packaging structure, which includes a lead frame and an LED chip. An upper packaging case and a lower packaging case are respectively arranged on the upper and lower sides of the lead frame. The LED chip is arranged in the upper package casing, and the pins of the LED chip are connected to the lead frame. An upper encapsulation glue covering the LED chips is also arranged in the upper encapsulation shell, and a lower encapsulation glue is arranged in the lower encapsulation shell. For this kind of LED device, it needs to be soldered on the substrate for use during use. Therefore, the technique of this method is complicated, and the product qualified rate is lower.

It can be seen from the above that the existing LED packaging generally uses LED chips or LED devices together with hard substrates such as aluminum substrates and ceramic substrates, and the resulting packaging structure is relatively complicated. In addition, there is a multi-layer structure between the LED chip and the heat sink, resulting in a large thermal resistance. In addition, the traditional packaging structure is mostly suitable for the use of blue-ray chips with dispensing process solutions, the process is cumbersome, and the product qualification rate is low.

Therefore, it is hoped in the art that the above-mentioned problems can be solved for LED packaging structures, especially white LED packaging structures.

Contents of the invention

In view of the above technical problems, the present invention aims to provide an LED packaging assembly, which can effectively reduce production costs. In addition, the present invention also hopes to provide an LED packaging assembly, wherein the substrate in the LED packaging assembly is flexible, and the structure of the substrate is simple, so that the formed thermal resistance is relatively low.

According to the present invention, there is provided an LED packaging assembly, comprising: a flexible substrate with a circuit layer formed therein; a reflective layer mounted on the first side of the flexible substrate; an LED chip mounted on the flexible substrate, The electrodes of the LED chip are electrically connected to the circuit layer through the reflective layer; the protective layer is arranged on the second side of the flexible substrate.

The LED package assembly according to the present invention is especially an LED package assembly capable of emitting white light. However, those skilled in the art can understand that the LED package assembly according to the present invention can also emit light of other colors after necessary known modifications are made.

In one embodiment, the LED chip is a white LED chip. In this case, the protective layer may be a polymer material layer, especially a polymer composite material layer containing titanium oxide. In particular, the LED chip is a white LED flip-chip, and its top surface and side surfaces are surrounded by hemispherical lenses.

In another embodiment, the LED chip is a blue LED flip chip. At this time, a phosphor layer or a hemispherical lens made of a material mixed with phosphor may be disposed around the LED chip.

Preferably, the phosphor is a mixture of one or more of yellow phosphor, red phosphor and green phosphor.

In another embodiment, the LED chip is a blue LED front-mount chip, which is electrically connected to the circuit layer by wire bonding.

According to the present invention, the protective layer is a metal layer, preferably made of copper, aluminum, gold, silver. In particular, the thickness of the protection layer is equal to or greater than the thickness of the circuit layer.

In one embodiment, an insulating layer is further provided between the flexible substrate and the protective layer, and the insulating layer is preferably made of PI, PET or epoxy resin.

In one embodiment, the LED package assembly further includes an adhesive layer disposed on a side of the protective layer away from the flexible substrate, which is used for connecting with a heat sink.

The LED packaging assembly according to the present invention has a flexible substrate, which expands its application range. In addition, the substrate of the LED packaging assembly has a simple structure, so that the formed thermal resistance is relatively low. In addition, the preparation of the LED packaging component is simple and the production cost is low.

Description of drawings

The present invention will be described below in conjunction with the accompanying drawings. It is easy to understand that the accompanying drawings are only provided for better understanding of the present invention, and should not be regarded as limiting the present invention.

Fig. 1 shows an LED package assembly according to a first embodiment of the present invention.

Fig. 2 shows an LED package assembly according to a first embodiment of the present invention.

Fig. 3 shows an LED package assembly according to a first embodiment of the present invention.

In the drawings, the same reference numerals designate the same or similar components. The drawings are not drawn to scale.

detailed description

The present invention will be described below by taking an LED packaging assembly capable of emitting white light as an example and in conjunction with the accompanying drawings.

FIG. 1 shows a white LED package assembly according to a first embodiment of the present invention. As shown in FIG. 1 , the white LED packaging assembly 10 includes a flexible substrate 11 on which a circuit layer 14 is formed. The flexible substrate 11 and the circuit layer 14 therein can be made of common materials and common processes well known in the art.

A reflective layer 15 is coated on a first side of the flexible substrate 11 , which is shown as the upper side in FIG. 1 . In one embodiment, the reflective layer 15 may be a white oil layer. An LED chip 16 is also installed on the first side of the flexible substrate 11 . In this embodiment, the LED chip 16 is a white LED flip chip. Preferably, the white LED flip chip is surrounded by a hemispherical lens 18 . However, it can be understood that this embodiment also includes the case of no lens 18, which is completely determined by those skilled in the art according to the needs of specific applications. The LED chip 16 includes an appropriate number of electrode portions 17 (only one is shown for clarity in the figure), which are connected to the circuit layer 14 in the flexible substrate 11 through the through holes opened in the reflective layer 15 . Thus, the electrical connection/signal connection between the LED chip 16 and the flexible substrate 11 is realized.

An insulating layer 12 is provided on an opposite second side of the flexible substrate 11 , which is shown as the lower side in FIG. 1 . The insulating layer 12 can be made of polyimide (PI), polyethylene terephthalate (PET) or epoxy resin, for example. A protective layer 13 is disposed on the side of the insulating layer 12 away from the flexible substrate 11 (ie, the lower side in FIG. 1 ). In this embodiment, the protective layer 13 is made of polymer material. Preferably, the protective layer 13 is made of a polymer composite material containing titanium oxide.

According to the invention, the protective layer 13 is connected to the heat sink (not shown) via an adhesive layer (not shown). The adhesive layer can be made, for example, of thermally conductive silicone grease or thermally conductive glue. Therefore, there are only a few layers of materials between the LED chip 16 and the heat sink, so that the formed thermal resistance is relatively small. This is because for the same material, the thermal resistance of the substrate is proportional to the number of layers of the material. Therefore, according to the present invention, only a small number of material layers are arranged between the LED chip 16 and the heat sink, resulting in a relatively small thermal resistance formed. In addition, because the flexible substrate 11 is used in the white LED package assembly 10, the package structure thereof is relatively simple, the production cost is reduced, and it can also be adapted to various purposes. In addition, due to the direct use of white LED chips, a series of LED packaging processes such as wire bonding, dispensing, and baking can be eliminated, the LED production process can be shortened, and the yield rate of products can be further improved. In addition, since the white LED chips have already been sorted, the sorting step can be omitted in subsequent operations. All of the above lead to simplification of the manufacturing process.

The LED package assembly 10 can be prepared by the following method. First, a flexible substrate 11 is prepared, in which a circuit layer 14 is formed, and an insulating layer 12 , a protective layer 13 and a reflective layer 15 are disposed on the flexible substrate 11 . Then, the white LED chip 16 is placed on the flexible substrate 11 , so that the electrode portion 17 of the white LED chip 16 is connected to the circuit layer 14 . A lens 18 may be provided around the LED chip 16 if desired. Afterwards, a curing step is performed, so that the white LED chip 16 is fixedly connected to the flexible substrate 11 . After that, light color detection is performed on the entire LED light source. Finally, an adhesive layer is coated on the free side of the protective layer 13 (the side away from the insulating layer 12 ), and is connected to the heat sink through the adhesive layer.

It can be seen from the above that the LED packaging assembly according to the present invention can be prepared with simple process steps, which greatly reduces the production cost.

Although the LED chip 16 is selected as a white LED flip chip in this embodiment, it can be understood that the LED chip 16 may also be a blue LED flip chip. At this time, in order to output white light, the lens 18 should be made of a transparent material mixed with phosphor. In some embodiments, the phosphor may be one or more of yellow phosphor, red phosphor and green phosphor in mixture. Thus, under the combined action of the blue LED flip chip and the lens containing phosphor powder of a specific color, the LED packaging assembly 10 can emit white light.

FIG. 2 shows a white LED package assembly according to a second embodiment of the present invention. As shown in FIG. 2 , the white light LED packaging assembly 20 is substantially the same as the white light LED packaging assembly 10 shown in FIG. 1 . Therefore, the difference lies in that the LED chip is a blue LED flip-chip 26 , and phosphor layers 28 are arranged on its top surface and side surfaces. Similarly, the phosphor layer 28 may be formed of a mixture of one or more of yellow phosphor, red phosphor and green phosphor. Thus, under the combined action of the blue LED flip chip and the lens of the phosphor layer 28 of a specific color, the LED package assembly 20 can emit white light.

Furthermore, in this embodiment, the protective layer 23 is made of a metal material. Preferably, the protective layer 23 is made of aluminum, copper, gold, silver and other materials. Preferably, the protective layer 23 is configured to have the same thickness as the flexible substrate 11 , especially the circuit layer formed therein. However, the protection layer 23 may also be configured to have a greater thickness than the flexible substrate 11 , especially the wiring layer formed therein. Therefore, the protective layer 23 can be designed to have different thicknesses according to different purposes, so as to meet the requirements of mechanical strength and heat dissipation performance. In addition, the material of the protective layer 23 can be designed according to heat dissipation requirements and welding requirements, which provides a high degree of design freedom.

In addition, in this embodiment, the insulating layer 22 is not necessary, but can also be omitted.

It is easy to understand that in this embodiment, the phosphor layer 28 can also be replaced by a lens made of a transparent material mixed with phosphor as in the first embodiment.

In an example not shown, the LED chips in the second embodiment may also be white LED chips. At this time, the phosphor layer 28 may be omitted.

The LED package assembly 20 can be prepared by the following method. Firstly, a flexible substrate 21 is prepared, in which a circuit layer is formed, and an insulating layer 22 , a protective layer 23 and a reflective layer are disposed on the flexible substrate 21 . Then, the blue LED chip 26 is placed on the flexible substrate 21 so that the electrode portion of the blue LED chip 26 is connected to the circuit layer. Afterwards, a curing step is performed, so that the white LED chip 26 is fixedly connected to the flexible substrate 21 . Then, a phosphor layer 28 may be coated or a lens 28 may be provided around the LED chip 26 . Take the setting of the lens 28 as an example, after which the curing is carried out again, and its temperature is set according to the parameters of the curing of silica gel. Afterwards, light color detection is performed on the entire LED light source. Finally, an adhesive layer is coated on the free side of the protective layer 23 (the side away from the insulating layer 22 ), and is connected to the heat sink through the adhesive layer.

Fig. 3 shows a white LED package assembly according to a third embodiment of the present invention. As shown in FIG. 3 , the white light LED package assembly 30 is substantially the same as the white light LED package assembly 10 shown in FIG. 1 . The difference is that the LED chip is a blue LED positive chip 36 . The blue LED positive chip 36 is surrounded by a lens 38 made of transparent material mixed with phosphor powder. In addition, the blue LED positive chip 36 is connected to the circuit layer of the flexible substrate through wire bonding. Wire bonding is well known to those skilled in the art, so a detailed description thereof is omitted here.

The manufacturing method of the above white LED package assembly 30 is substantially similar to the manufacturing method of the white LED package assembly 10 in the first embodiment. The difference is that after the blue LED positive chip 36 is mounted on the flexible substrate, a wire bonding process is also performed.

In an example not shown, the LED chips in the third embodiment may also be white LED chips. In this case, the lens 38 can be omitted, or the lens 38 does not contain phosphor material.

Although the present invention has been described in detail above in conjunction with a white light LED package assembly, it is easy to understand that the present invention can also be applied to LED package assemblies that emit light of other colors. At this time, light of other colors, such as yellow light with a color temperature of 3000k, can be emitted only through some transformations known to those skilled in the art.

The present invention has been described in detail above with reference to the accompanying drawings and through specific embodiments. It is readily understood, however, that these descriptions are not to be construed as limiting the scope of the invention. The protection scope of the present invention is defined by the appended claims, and any modification based on the claims of the present invention belongs to the protection scope of the present invention.

Claims (10)

1. a kind of LED package assemblings, including：

Flexible base board, is formed with line layer；

Reflector layer on the first side of the flexible base board is set；

LED chip on the flexible base board, the electrode of the LED chip through the reflector layer with the circuit Layer electrical connection；And

The protective layer being arranged on the second side of the flexible base board.

2. LED package assemblings according to claim 1, it is characterised in that the protective layer is polymer material layer, described Polymer material layer is the polymer composite layer containing titanium oxide.

3. LED package assemblings according to claim 1 and 2, it is characterised in that the LED chip is flip-chip, and Its top surface and side are surrounded by hemispherical lens.

4. LED package assemblings according to claim 1, it is characterised in that the LED chip is blue-ray LED flip-chip, And phosphor powder layer or saturating by hemispherical made by the material for being mixed with fluorescent material is provided with around the LED chip Mirror.

5. LED package assemblings according to claim 4, it is characterised in that the fluorescent material is yellow fluorescent powder, red glimmering The mixture of one or more in light powder and green emitting phosphor.

6. LED package assemblings according to claim 1, it is characterised in that the LED chip is the positive cartridge chip of blue-ray LED, It passes through wire bonding and electrically connects with the line layer, and the LED package assemblings are white-light LED encapsulation component.

7. LED package assemblings according to any one of claim 1,4 to 6, it is characterised in that the protective layer is metal Layer, the metal level is copper, aluminium, gold or silver.

8. LED package assemblings according to claim 7, it is characterised in that the thickness of the protective layer is equal to or more than institute State the thickness of line layer.

9. LED package assemblings according to claim 1, it is characterised in that between the flexible base board and protective layer also Insulating barrier is provided with, the insulating barrier is made with PI, PET or epoxy resin.

10. LED package assemblings according to claim 1, it is characterised in that the LED package assemblings also include being arranged on The adhesive layer of the side away from the flexible base board of the protective layer, it is used to be attached with heat sink.