阅读说明：本技术 一种高功率密度cob器件 (High power density COB device ) 是由 王孟源 曾伟强 于 2019-08-20 设计创作，主要内容包括：本发明涉及一种高功率密度COB器件,包括基板、若干个设置在基板上的叠层结构、以及将叠层结构覆盖的封装胶层,所述叠层结构包括第一焊盘、第二焊盘、第一垂直芯片、第二垂直芯片、倒装芯片和正装芯片,所述第一焊盘和第二焊盘均设置在基板上,所述第一垂直芯片设置在第一焊盘上,所述第二垂直芯片设置在第二焊盘上,所述倒装芯片安装在第一垂直芯片和第二垂直芯片上,以将第一垂直芯片和第二垂直芯片形成导电连接,所述正装芯片设置在倒装芯片上,并通过导线分别与第一焊盘和第二焊盘连接。本发明提供的高功率密度COB器件通过形成层叠式结构,提高相同面积内部的LED芯片的安放数量,从而提高COB器件的功率密度。(The invention relates to a high-power-density COB device which comprises a substrate, a plurality of laminated structures arranged on the substrate and a packaging adhesive layer covering the laminated structures, wherein each laminated structure comprises a first bonding pad, a second bonding pad, a first vertical chip, a second vertical chip, an inverted chip and a forward chip, the first bonding pad and the second bonding pad are arranged on the substrate, the first vertical chip is arranged on the first bonding pad, the second vertical chip is arranged on the second bonding pad, the inverted chip is arranged on the first vertical chip and the second vertical chip to form conductive connection, and the forward chip is arranged on the inverted chip and is respectively connected with the first bonding pad and the second bonding pad through leads. According to the high-power-density COB device, the stacked structure is formed, the number of the LED chips in the same area is increased, and therefore the power density of the COB device is increased.)

1. The utility model provides a high power density COB device, its characterized in that includes base plate, the laminated structure of a plurality of setting on the base plate and the encapsulation glue film that covers laminated structure, laminated structure includes first pad, second pad, first perpendicular chip, the perpendicular chip of second, flip chip and just adorns the chip, first pad and second pad all set up on the base plate, first perpendicular chip sets up on first pad, the perpendicular chip setting of second is on the second pad, flip chip installs on first perpendicular chip and the perpendicular chip of second to form electrically conductive connection with the perpendicular chip of first perpendicular chip and second, just adorn the chip setting on the flip chip to be connected with first pad and second pad respectively through the wire.

2. The high power density COB device of claim 1, wherein the positive electrode of the first vertical chip is mounted on the negative electrode of the first pad, the negative electrode of the second vertical chip is mounted on the positive electrode of the second pad, the positive electrode of the flip chip is mounted on the negative electrode of the first vertical chip, the negative electrode of the flip chip is mounted on the positive electrode of the second vertical chip, the positive electrode of the positively mounted chip is connected to the negative electrode of the second pad by a wire, and the negative electrode of the positively mounted chip is connected to the positive electrode of the first pad by a wire.

3. The COB device with high power density according to claim 1, further comprising a light distribution layer, wherein the light emergent surface of the light distribution layer is arc-shaped, the cross section of the light distribution layer is in an axisymmetric structure, the light distribution layer covers the packaging adhesive layer, and light emitted by the chip is refracted out from the light emergent surface of the light distribution layer through the packaging adhesive layer and the light distribution layer in sequence.

4. High power density COB device according to claim 3, wherein the maximum width of the light distributing layer is 2-8 times the distance between the first vertical chip and the second vertical chip.

5. High power density COB device of claim 4, wherein the distance between the light-emitting surface of the light distribution layer and the chip being mounted is a, and the total height of the stacked structure is b, (3-6) × b.

6. The high power density COB device of claim 1, wherein the substrate is a ceramic substrate and the first and second pads are metal layers printed on a surface of the substrate.

7. High power density COB device of claim 1, wherein the substrate is a metal substrate, and the first and second pads are filled with an insulating material therebetween for insulating the first and second pads.

Technical Field

The invention relates to the technical field of LED packaging, in particular to a high-power-density COB device.

Background

Ultraviolet and deep ultraviolet LEDs have significant application values in medical treatment, sterilization, photocuring, 3D printing, lighting, data storage, secure communication, and the like. The deep ultraviolet LED has more advantages than traditional gas ultraviolet light sources such as mercury lamps, xenon lamps and the like, and has huge social and economic values due to small volume, simple structure, controllable wavelength, good integration, long service life, low energy consumption and zero pollution.

COB light source package, i.e., chip-on-board package, is one of bare chip mounting technologies, an LED chip is mounted on a printed circuit board, electrical connection between the chip and a substrate is achieved by a lead stitching method, and is covered with resin to ensure reliability. With the wide application of the COB illumination products, for some COB products with small installation area and high light-emitting brightness requirement, the existing method is to densely arrange the LED chips as much as possible, but the market demand still cannot be met. Therefore, there is a need for a COB device with high power density to solve the above problems.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a high-power-density COB device, which forms a laminated structure through a plurality of chips, and improves the power density of the COB device.

The invention also aims to solve the technical problem of improving the light-emitting efficiency of the device.

In order to solve the technical problem, the invention provides a high-power-density Chip On Board (COB) device, which comprises a substrate, a plurality of laminated structures arranged on the substrate and a packaging adhesive layer covering the laminated structures, wherein each laminated structure comprises a first bonding pad, a second bonding pad, a first vertical chip, a second vertical chip, a flip chip and a forward chip, the first bonding pad and the second bonding pad are arranged on the substrate, the first vertical chip is arranged on the first bonding pad, the second vertical chip is arranged on the second bonding pad, the flip chip is arranged on the first vertical chip and the second vertical chip to form conductive connection, and the forward chip is arranged on the flip chip and is respectively connected with the first bonding pad and the second bonding pad through wires.

As an improvement of the above scheme, the positive electrode of the first vertical chip is mounted on the negative electrode of the first bonding pad, the negative electrode of the second vertical chip is mounted on the positive electrode of the second bonding pad, the positive electrode of the flip chip is mounted on the negative electrode of the first vertical chip, the negative electrode of the flip chip is mounted on the positive electrode of the second vertical chip, the positive electrode of the positive chip is connected with the negative electrode of the second bonding pad through a wire, and the negative electrode of the positive chip is connected with the positive electrode of the first bonding pad through a wire.

As an improvement of the scheme, the LED light distribution device further comprises a light distribution layer, the light outlet surface of the light distribution layer is arc-shaped, the cross section of the light distribution layer is of an axisymmetric structure, the light distribution layer covers the packaging adhesive layer, and light emitted by the chip sequentially passes through the packaging adhesive layer and the light distribution layer and is refracted out from the light outlet surface of the light distribution layer.

As an improvement of the scheme, the maximum width of the light distribution layer is 2-8 times of the distance between the first vertical chip and the second vertical chip.

In an improvement of the above scheme, a distance between the light emitting surface of the light distribution layer and the chip being mounted is a, and a total height of the stacked structure is b, where a is (3-6) × b.

As an improvement of the above scheme, the substrate is a ceramic substrate, and the first pad and the second pad are metal layers printed on the surface of the substrate.

As an improvement of the above scheme, the substrate is a metal substrate, and an insulating material is filled between the first pad and the second pad to realize insulation between the first pad and the second pad.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the characteristics of the face-up chip, the flip chip and the vertical chip, the face-up chip, the flip chip and the vertical chip are stacked to form a laminated structure, the number of the LED chips in the same area is increased, and therefore the power density of the COB device is increased.

2. The light distribution layer directly covers the packaging adhesive layer, the refractive index difference between the light distribution layer and the packaging adhesive layer is not large, light emitted by the chip is directly emitted through the packaging adhesive layer and the light distribution layer, step-shaped refractive index change cannot occur, light can be emitted, on the other hand, the light emitting surface of the light distribution layer is a cambered surface, light of a COB device is emitted in a concentrated mode and cannot be scattered to a peripheral area, and the light emitting efficiency of the COB device is further guaranteed.

Drawings

Fig. 1 is a schematic structural view of a COB device according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a first vertical chip according to the present invention;

FIG. 3 is a schematic diagram of a flip chip of the present invention;

FIG. 4 is a schematic structural diagram of a front-mounted chip according to the present invention;

fig. 5 is a schematic structural view of a COB device according to a second embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and preferred embodiments.

Referring to fig. 1, the high power density COB device provided by the present invention includes a substrate 1, a plurality of stacked structures disposed on the substrate 1, and an encapsulating adhesive layer 8 covering the stacked structures.

The stacked structure of the present invention includes a first pad 2, a second pad 3, a first vertical chip 4, a second vertical chip 5, a flip chip 6, and a front-mounted chip 7.

The substrate 1 of the present invention is used for mounting other structures of a COB device, and may be a ceramic substrate or a metal substrate, and the type of the substrate 1 is specifically selected according to actual needs.

According to the invention, a first bonding pad 2 and a second bonding pad 3 are positioned on a substrate 1, the first bonding pad 2 and the second bonding pad 3 are both provided with a positive electrode and a negative electrode, when the substrate 1 is a ceramic substrate, the ceramic substrate is an aluminum nitride substrate or an aluminum oxide substrate, and the first bonding pad 2 and the second bonding pad 3 are metal layers printed on the surface of the substrate 1; when the substrate 1 is a metal substrate, the metal substrate is a copper substrate or an aluminum substrate, an insulating material is filled between the first bonding pad 2 and the second bonding pad 3 to realize insulation between the first bonding pad 2 and the second bonding pad 3, and the first bonding pad 2 and the second bonding pad 3 realize electric connection between the first vertical chip 4, the second vertical chip 5, the flip chip 6 and the normal chip 7 and an external power supply.

The first vertical chip 4 of the present invention is mounted on the first pad 2, the second vertical chip 5 is mounted on the second pad 3, the flip chip 6 is mounted on the first vertical chip 4 and the second vertical chip 5 to form the first vertical chip 4 and the second vertical chip 5 into conductive connection, and the flip chip 7 is disposed on the flip chip 6 and connected to the first pad 2 and the second pad 3 through wires, respectively.

Referring to fig. 2, the first vertical chip 4 and the second vertical chip 5 of the present invention are vertical ultraviolet LED chips, and include a first positive electrode 11, a first light emitting structure 12, and a first negative electrode 13, wherein the first positive electrode 11 and the first negative electrode 13 are disposed at upper and lower ends of the light emitting structure 12.

Referring to fig. 3, the flip chip 6 of the present invention is a flip structure ultraviolet LED chip, and includes a second positive electrode 21, a second light emitting structure 22, and a second negative electrode 23, wherein the second positive electrode 21 and the second negative electrode 23 are disposed on the same side of the second light emitting structure 22.

Referring to fig. 4, the front chip 7 of the present invention is a front structure ultraviolet LED chip, and includes a third positive electrode 31, a third light emitting structure 32 and a third negative electrode 33, wherein the third positive electrode 31 and the third negative electrode 33 are disposed on the same side of the third light emitting structure 32.

Specifically, the first positive electrode 11 of the first vertical chip 4 is mounted on the negative electrode of the first bonding pad 2, the first negative electrode 13 of the second vertical chip 5 is mounted on the positive electrode of the second bonding pad 3, the second positive electrode 21 of the flip chip 6 is mounted on the first negative electrode 11 of the first vertical chip 4, the second negative electrode 23 of the flip chip 6 is mounted on the second positive electrode 11 of the second vertical chip 5, the third positive electrode 31 of the positively mounted LED chip 7 is connected with the negative electrode of the second bonding pad 3 through a wire, and the third negative electrode 33 of the positively mounted LED chip 7 is connected with the positive electrode of the first bonding pad 3 through a wire. In the present invention, the electrodes and the pads may be electrically connected by solder paste soldering or eutectic soldering, and the present invention is not limited in particular.

It should be noted that the first bonding pad 2, the first vertical chip 4, the flip chip 6, the second vertical chip 5 and the second bonding pad 3 of the present invention are connected in sequence to form one electrical circuit, and the normal chip 7, the first bonding pad 2 and the second bonding pad 3 form another electrical circuit.

The packaging adhesive layer 8 of the present invention covers the laminated structure. Preferably, the encapsulation adhesive layer 8 further extends to the substrate 1, and covers the stacked structure therein to protect the first vertical chip 4, the second vertical chip 5, the flip chip 6 and the normal chip. The encapsulation glue layer 8 is made by fluorescent glue, and is specific, the encapsulation glue layer 8 is made for the mixture of silica gel and phosphor powder.

According to the characteristics of the face-up chip, the flip chip and the vertical chip, the face-up chip, the flip chip and the vertical chip are stacked to form a laminated structure, the number of the LED chips in the same area is increased, and therefore the power density of the COB device is increased.

Referring to fig. 4, in order to improve the light extraction efficiency of the device, the invention provides a light distribution layer 9 on the encapsulation adhesive layer 8. The light distribution layer 9 is covered on the packaging adhesive layer 8, and light emitted by the chip sequentially passes through the packaging adhesive layer 8 and the light distribution layer 9 and is refracted out of the light emergent surface of the light distribution layer. Specifically, the light-emitting surface of the light distribution layer 9 of the present invention is arc-shaped, and the cross section thereof is in an axisymmetric structure. The light distribution layer 9 is made of transparent packaging adhesive.

The light distribution layer directly covers the packaging adhesive layer, the refractive index difference between the light distribution layer and the packaging adhesive layer is not large, light emitted by the chip is directly emitted through the packaging adhesive layer and the light distribution layer, step-shaped refractive index change cannot occur, light can be emitted, on the other hand, the light emitting surface of the light distribution layer is a cambered surface, light of a COB device is emitted in a concentrated mode and cannot be scattered to a peripheral area, and the light emitting efficiency of the COB device is further guaranteed.

The invention further limits the distance between the chip and the light distribution layer to achieve the optimal light emitting effect. Preferably, the maximum width of the light distribution layer is 2-8 times the distance between the first vertical chip and the second vertical chip.

Preferably, the distance between the light emitting surface of the light distribution layer and the chip being mounted is a, the total height of the laminated structure is b, and a is (3-6) × b.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.