CN108831983B

CN108831983B - Packaging method of LED device and LED device

Info

Publication number: CN108831983B
Application number: CN201810616873.3A
Authority: CN
Inventors: 高春瑞; 郑剑飞; 郑文财
Original assignee: Xiamen Dacol Photoelectronics Technology Co Ltd
Current assignee: Xiamen Dacol Photoelectronics Technology Co Ltd
Priority date: 2018-06-15
Filing date: 2018-06-15
Publication date: 2020-02-04
Anticipated expiration: 2038-06-15
Also published as: CN108831983A

Abstract

The invention relates to an LED device and a packaging method thereof.

Description

Packaging method of LED device and LED device

Technical Field

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

Background

The LED packaging devices most widely used in the market at present are mainly SMD-LED (surface mounted device) and COB-LED (chip-on-board package), wherein the structure of the SMD-LED is shown in fig. 1a, and includes a packaging support 10a, an LED chip 12a die-bonded on the packaging support, a gold wire 14a, and a packaging adhesive 16a, wherein the packaging adhesive is generally flush with a cup of the packaging support or forms a substantially hemispherical lens on the cup; the structure of the COB-LED is shown in fig. 1b, and includes a substrate 10b, an LED chip 12b die-bonded on the substrate, a gold wire 14b, and an encapsulant 16b, wherein the encapsulant has a generally hemispherical shape. Because the cup of the packaging support is generally in the shape of an inverted round table and the lens or COB packaging glue is generally hemispherical, the light intensity of the LED packaging device in the central area of the packaging structure is far greater than that of the peripheral area, so that the light intensity distribution of the LED packaging device is usually changed by an additional lens on occasions with requirements on uniformity of illumination.

Disclosure of Invention

The invention aims to provide an LED device and a packaging method thereof, and aims to solve the problem that the existing LED device is poor in light intensity distribution uniformity.

The specific scheme is as follows:

a packaging method of an LED device comprises the following steps:

s1, assembling a packaging substrate;

s2, die bonding in the packaging substrate;

s3, coating packaging glue on the packaging substrate, wherein the LED chip is covered by the packaging glue;

s4, heating and baking the packaging substrate processed in the step S3 to enable the packaging glue to be primarily cured into gel;

s5, pressing down the center area of the top of the packaging adhesive by the tool for the packaging adhesive processed in the step S4 so that the packaging adhesive forms a concave cavity downwards in the center area of the top of the packaging adhesive;

s6, the package substrate processed in step S5 is baked to cure the package adhesive completely.

Further, the viscosity of the encapsulation adhesive in the step S3 is 15000 to 20000 Pas.

Further, the step S5 is implemented by:

s51, placing the packaging substrate processed in the step S3 on a dispensing machine, and enabling the central area of the packaging glue to be located right below a dispensing needle head;

and S52, closing the dispensing machine to discharge the glue, and enabling a dispensing needle of the dispensing machine to move downwards and extrude the central area of the packaging glue by the dispensing needle so as to form a concave cavity downwards in the central area of the top of the packaging glue.

Further, there is a step S51 'between the above steps S51 and S52, and the step S51' includes the following steps: a downward pressing tool is fixedly arranged on a dispensing needle head of the dispensing machine, and the lower end of the downward pressing tool is a downward pressing part matched with the shape of the concave cavity.

Furthermore, the structure of the pressing part is in a shape of a cone, a circular truncated cone or a frustum of a pyramid.

Further, the shape of the encapsulation adhesive is a hemisphere after the encapsulation adhesive is coated in step S3.

Further, the package substrate is a ceramic substrate, and the step S1 further includes a dehumidification step.

Further, a dam is formed on the package substrate in step S1, and the LED chip in step S2 is die bonded in the region surrounded by the dam.

The invention also provides an LED device, which comprises a packaging substrate, an LED chip and packaging glue, wherein the LED chip is fixedly crystallized on the packaging substrate, the packaging glue is coated on the packaging substrate and covers the LED chip, and a concave cavity downwards concaved is formed in the central area of the packaging glue.

Compared with the prior art, the LED device and the packaging method thereof provided by the invention have the following advantages: according to the LED device packaging method provided by the invention, a concave cavity is formed in the central area of the packaging glue through simple steps, so that the middle glue body moves towards two sides, the light output quantity in the middle is reduced, the light output rates at two sides are increased, and the uniformity of the light emitting surface of the lamp bead is ensured. In addition, with this package design, end customers can reduce the use of lenses, which reduces cost and overall lamp volume.

Drawings

Fig. 1a shows a schematic diagram of a prior art SMD-LED packaged device.

Fig. 1b shows a schematic diagram of a prior COB-LED packaged device.

Fig. 2 shows a schematic diagram of an LED package device according to the present application after pre-curing of the package paste.

Fig. 3 shows a schematic diagram of a process of forming a groove of the LED package device of the present application.

Fig. 4 shows a schematic diagram of an LED packaged device of the present application.

Fig. 5 shows a light distribution graph of the LED package device of the present application.

Fig. 6 shows a light distribution graph of a conventional SMD-LED package device.

Detailed Description

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 2 to 3, the present invention provides a method for packaging an LED device, including the steps of:

s1, providing a package substrate 20, wherein the package substrate 20 shown in fig. 2 is a ceramic substrate (metal substrates such as aluminum substrates can also be used, but the ceramic substrate has good heat dissipation performance and is suitable for packaging high-power LED devices), and the ceramic substrate is contaminated with some moisture during storage, so that the moisture removal process is performed before the packaging step is performed.

S2, die bonding is performed in the package substrate 20, and the forward mounting of the LED chip 22 is illustrated in FIG. 2 by way of example, a proper amount of die bonding glue is dispensed on the ceramic substrate 20, then the LED chip 22 is placed on the die bonding glue for positioning and fixing, and then the LED chip is placed in an oven for baking (the baking temperature and time are determined according to the performance of the die bonding glue, for example, the die bonding glue of the Japanese Xinyue KER-3000-M2 is used for die bonding, and the baking temperature and time are respectively 150 ℃/2H), so that the die bonding glue is completely cured; after the die attach adhesive is completely cured, wire bonding is performed by using a gold wire bonder, so that the electrodes on the LED chip 22 are communicated with the metal circuit on the package substrate 20 through gold wires 24;

s3, coating the package adhesive 26 on the package substrate 20, wherein the package adhesive 26 covers the LED chip 22, the package adhesive 26 in fig. 2 is a package adhesive mixed with phosphor, the amount and the allocation of the phosphor can be determined according to the required color temperature, in order to limit the flow of the package adhesive, a dam can be formed on the package substrate 20 in advance, and the LED chip is die-bonded in the area surrounded by the dam; in the present embodiment, in order to reduce the fluidity of the encapsulating adhesive 26 for the subsequent molding operation, the viscosity of the encapsulating adhesive 26 is preferably 15000 to 20000 Pas.

S4, the package substrate 20 processed in step S3 is placed into an oven to be heated and baked, so that the package glue 26 is primarily cured into a gel (jelly) state, the baking temperature and time are lower than the curing temperature of the package glue, for example, the curing temperature of the package glue used in this embodiment is 150 ℃/2H, and the baking temperature and time used in step S4 is 100 ℃/10 min, so as to form the LED package device shown in fig. 2.

S5, as shown in fig. 3, pressing down the top center area of the packaging adhesive processed in step S4 by the pressing tool 30 to form a concave cavity 260 in the top center area of the packaging adhesive, as shown in fig. 4, wherein the cavity 260 is only partially restored after the tool 30 is removed (the cavity 260 is formed by increasing the volume of the cavity in advance according to the restoration amount of the cavity) because the packaging adhesive 26 is pre-cured to gel, so that the cavity 260 is still remained after being completely cured; it should be understood that the tool 30 does not damage the gold wires in the package adhesive during the process of pressing down the cavity 260.

S6, the package substrate 20 processed in step S5 is baked by heating to cure the package adhesive 26 completely, wherein the curing temperature of the package adhesive used in this embodiment is 150 ℃/2H, i.e., baking for 2 hours in an oven at 150 ℃, so as to cure the package adhesive 26 completely and make the top center region of the package adhesive 26 have a concave cavity 260.

As shown in fig. 5 and 6, fig. 5 is a light distribution curve of the LED package device manufactured in the present embodiment, fig. 6 is a light distribution curve of a conventional SMD-LED package device (the light distribution curve in fig. 6 is a light distribution curve of a commercially available osplen GW pslr31.em model), and it is apparent from fig. 5 and 6 that the difference between the light intensity of the central area and the light intensity of the peripheral area of the LED package device manufactured in the present embodiment is not very large, that is, the uniformity of the light intensity of the LED package device is better than that of the conventional LED package device.

As a preferred embodiment of the step S5, the step S5 is implemented by:

s51, placing the packaging substrate processed in the step S4 on a dispensing machine, and enabling the central area of the packaging glue to be located right below a dispensing needle head;

Namely, the dispensing needle head of the dispensing machine is used as a pressing tool, and the dispensing machine has better controllability and precision. On the basis that the dispensing needle is generally small and sharp, and the diameter of the cavity formed is also small, it is more preferable to have a step S51 'between the above steps S51 and S52, where the step S51' includes the following steps: a pressing tool 30 as shown in fig. 3 is fixedly installed on the dispensing needle of the dispenser, and the lower end of the pressing tool 30 is a pressing part 300 matched with the shape of the cavity. Making the shape and size of the cavity more controllable. And the structure of the pressing part is preferably in a shape of a cone, a circular truncated cone or a frustum of a pyramid, so that the manufactured LED packaging device has better light intensity uniformity.

The invention also provides an LED package device as shown in fig. 4, which includes a package substrate 20, an LED chip 22 and a package adhesive 26, wherein the LED chip 22 is die-bonded on the package substrate 20, the package adhesive 26 is coated on the package substrate and covers the LED chip, and a concave cavity 260 is formed in a central area of the package adhesive and is recessed downward.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for packaging an LED device is characterized by comprising the following steps:

s1, assembling a packaging substrate;

s2, die bonding in the packaging substrate;

this step S5 is realized by the following steps:

s52, closing the dispensing machine to discharge the glue, enabling a dispensing needle of the dispensing machine to move downwards, and enabling the dispensing needle to extrude the central area of the packaging glue so as to form a concave cavity downwards in the central area of the top of the packaging glue;

2. The method of claim 1, wherein the viscosity of the encapsulant in step S3 is 15000 to 20000 Pas.

3. The packaging method of claim 1, further comprising a step S51 'between the steps S51 and S52, wherein the step S51' comprises the following steps: a downward pressing tool is fixedly arranged on a dispensing needle head of the dispensing machine, and the lower end of the downward pressing tool is a downward pressing part matched with the shape of the concave cavity.

4. The method of claim 3, wherein the structure of the press-down portion is in the shape of a cone, a truncated cone, or a truncated pyramid.

5. The method of claim 1, wherein the encapsulation adhesive is shaped like a hemisphere after the encapsulation adhesive is applied in step S3.

6. The method of claim 1, wherein the package substrate is a ceramic substrate, and the step S1 further includes a dehumidification step.

7. The method of claim 1, wherein a dam is further formed on the package substrate in step S1, and the LED chip in step S2 is die-bonded in the region surrounded by the dam.