CN110690336B

CN110690336B - Energy-saving LED lighting device and manufacturing method thereof

Info

Publication number: CN110690336B
Application number: CN201910976681.8A
Authority: CN
Inventors: 侯立东
Original assignee: Derun Planning And Design Institute Shenzhen Co Ltd
Current assignee: Derun planning and Design Institute (Shenzhen) Co., Ltd
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2020-12-25
Anticipated expiration: 2039-10-15
Also published as: CN110690336A

Abstract

The invention provides an energy-saving LED lighting device and a manufacturing method thereof, the energy-saving LED lighting device adopts a thermal contraction material to prevent disconnection of a welding wire and peeling of an LED chip, fluorescent resin and a heat dissipation substrate, can realize improvement of packaging yield, and can improve light-emitting rate; the manufacturing method of the invention is extremely simple and has lower manufacturing cost.

Description

Energy-saving LED lighting device and manufacturing method thereof

Technical Field

The invention relates to the field of LED lighting packaging, in particular to an energy-saving LED lighting device and a manufacturing method thereof.

Background

The existing LED packaging structure is mostly COB structure, i.e. chip-on-board structure, which usually needs to consider the heat dissipation problem. Referring to fig. 6(a), an LED chip 21 is fixed on a heat dissipation substrate 20 via an adhesive layer 22, and the LED chip 21 is electrically connected to a wiring layer of the heat dissipation substrate 20 by a bonding wire 23 to realize power supply, and is finally sealed and color temperature-adjusted using a fluorescent resin 24. However, due to the problem of unbalanced thermal matching, the LED chip 21 and the fluorescent resin 24 are easily peeled off from the heat dissipation substrate 20, resulting in the invasion of moisture. In addition, most of the fluorescent resin 24 is made of relatively inexpensive materials such as epoxy resin and silicone resin, which are thermally expansive materials and have an outward tensile force F when heated, as shown in fig. 6(b), the existence of such a force F may cause the connection between the bonding wire 23 and the LED chip 21 to be broken, resulting in package failure.

Disclosure of Invention

In order to solve the above problems, the present invention provides an energy-saving LED lighting device, including:

a substrate having a circuit layer;

an LED chip having an electrode, a back surface of the LED chip being attached to the wiring layer by an adhesive layer;

a bonding wire electrically connecting the electrode and the circuit layer;

a heat-shrinkable material completely sealing the bonding wires and the electrodes and sealing at least a part of a side surface of the LED chip;

and the fluorescent resin at least covers a part of the heat shrinkage material and the light emitting surface of the LED chip.

Wherein the heat shrinkable material seals a portion of two opposite side surfaces of the LED chip.

In one embodiment, the heat shrinkable material encapsulates a portion of two opposing sides of the LED chip.

In one embodiment, the fluorescent resin completely encapsulates the heat shrinkable material.

In one embodiment, the heat shrinkable material completely seals the light exit surface of the LED chip.

In one embodiment, the heat shrinkable material has two convex mirror structures that are symmetric along the center of the LED chip.

In one embodiment, the fluorescent resin completely covers the heat shrinkable material.

In one embodiment, the top surface of the fluorescent resin has a convex structure.

In one embodiment, the substrate has a trench around the LED chip, and the heat shrinkable material fills at least a portion of the trench.

In one embodiment, the fluorescent resin fills another portion of the trench.

In one embodiment, the present invention provides a method of manufacturing an energy saving LED lighting device, comprising:

(1) fixing an LED chip on the substrate by using an adhesive layer;

(2) electrically connecting the electrodes of the LED chip with the circuit layer of the substrate by using bonding wires;

(3) dispensing and curing to form a heat-shrinkable material, the heat-shrinkable material completely sealing the bonding wires and the electrodes and sealing at least a portion of the side surface of the LED chip;

(4) and injection molding to form fluorescent resin, wherein the fluorescent resin at least covers a part of the heat shrinkage material and the light emitting surface of the LED chip.

The invention has the following advantages:

the energy-saving LED lighting device adopts the thermal contraction material to prevent the disconnection of the welding wire and the peeling of the LED chip, the fluorescent resin and the heat dissipation substrate, can realize the improvement of the packaging yield, and can improve the light-emitting rate; the manufacturing method of the invention is extremely simple and has lower manufacturing cost.

Drawings

Fig. 1 is (a) a sectional view and (b) a plan view of an energy saving LED lighting device of a first embodiment;

fig. 2 is (a) a sectional view and (b) a plan view of an energy saving LED lighting device of a second embodiment;

fig. 3 is (a) a sectional view and (b) a plan view of an energy saving LED illumination device of a third embodiment;

fig. 4 is (a) a sectional view and (b) a plan view of an energy saving LED illumination device of a fourth embodiment;

fig. 5 is (a) a sectional view and (b) a plan view of an energy saving LED illumination device of a fifth embodiment;

fig. 6 is a schematic diagram of a prior art LED lighting device.

Detailed Description

The energy-saving LED lighting device can prevent the problem of mismatching of thermal stress of the LED chip, the fluorescent resin and the heat dissipation substrate, and can ensure the reliability of bonding wire connection and improve the light emitting efficiency. The thermal expansion material used in the present invention means a material that expands in volume when heated, and the thermal contraction material means a material that contracts in volume when heated.

First embodiment

Referring to fig. 1(a), the LED chip comprises an LED chip 2 fixed on a substrate 1 by an adhesive layer 3, wherein the LED chip is a gallium nitride-based LED chip, and may also be a mini-LED chip; the substrate 1 is a heat dissipation substrate, such as an LTCC substrate, a DBC substrate, etc., having a wiring layer thereon. The adhesive layer 3 has permanent adhesion, and may be selected from high polymer adhesive materials, which are conventional in the art and will not be described in detail herein.

The back of the LED chip 2 is attached to the circuit layer through an adhesive layer 3; the light-emitting surface of the LED chip 2 faces upward, and the edge of the light-emitting surface has an electrode (not shown) electrically connected to the circuit layer through a bonding wire 4. The bonding wire 4 is a copper wire, a gold wire, a silver wire, or the like. The wire 4 is wire bonded by a wire bonding tool, which may be a wedge bond head, and the wire 4 has an upwardly projecting arcuate shape.

In the prior art, the bonding wire 4 is easily broken due to the tensile force of the fluorescent resin; in order to solve this problem, the present invention utilizes a dispensing technique to form a heat shrinkable material 5 around the bonding wire 4, and the heat shrinkable material 5 covers the bonding wire 4 and the electrode (not shown). Referring to fig. 1(b), in the present embodiment, the heat shrinkable material 5 is only disposed on a portion of two side surfaces of the LED chip 2, and the heat shrinkable material 5 connects the light emitting surface and the upper surface of the substrate 1. Of course, the position of the heat shrinkable material 5 may be different according to the position of the bonding wire. The heat shrinkable material 4 has a heat shrinkable property having a stress F2 of shrinking inward.

The heat-shrinkable material 5 is covered with fluorescent resin 6 which covers the heat-shrinkable material 5 and the light-emitting surface of the LED chip 2. The fluorescent resin 6 is a resin material such as epoxy resin, silicone resin, etc. doped with fluorescent powder, and has a positive thermal expansion coefficient, which generates an outwardly-stretching stress F1. The heat shrinkable material 4 may be polyvinylidene chloride, polyvinyl chloride, PET, polyester resin material, etc., and in this embodiment, it may be a transparent and translucent material.

The stress F1 should be smaller than the stress F2 so that the wire 4 eventually generates a downward force which does not cause the wire 4 to break due to the protruding arc shape of the wire 4, ensuring reliability of the wire connection. Further, since F1 is smaller than F2, the structure on the substrate exhibits a compressive stress as a whole, that is, a stress that contracts toward the center, and the tensile force of the substrate 1 (the substrate is generally a ceramic material, such as LTCC, DBC, or the like, and has a tensile force) can be cancelled, thereby preventing the LED chip 2 and the fluorescent resin 6 from peeling off from the substrate 1.

Second embodiment

In the first embodiment, since the structure on the substrate is generally expressed as a shrinkage stress, the heat shrinkable material 5 presses down the LED chip 2 and adheres to the substrate 1, and if the bonding force of the heat shrinkable material 5 to the substrate is too small, peeling is also easily generated. For this reason, in the present embodiment, referring to fig. 2(a), a groove 7 is formed on the substrate 1 around the LED chip 2, and the groove 7 may be two or four discrete grooves or the like, or may be a ring-shaped structure surrounding the LED chip 2. Referring to fig. 2(b), the heat shrinkable material 5 fills a portion of the trench 7, and the fluorescent resin 6 fills the other portion of the trench 7, so that the bonding force between the fluorescent resin and the heat shrinkable material and the substrate can be increased, and the reliability of the heat shrinkable material 5 in pressing the LED chip 2 can be improved.

Third embodiment

Referring to fig. 3(a), in this embodiment, the heat shrinkable material 5 completely seals the side of the LED chip 2, and its pressing force is greater. And, a part of the surface of the heat shrinkable material 5 and the light emitting surface groove are a concave portion, the fluorescent resin 6 fills the concave portion, and a convex arc surface (i.e., a convex structure) is formed due to surface tension, and the arc surface can increase the light emitting rate. Referring to fig. 3(b), at this time, the fluorescent resin 6 covers only a portion of the heat shrinkable material. Of course, in this embodiment, it is also possible to have, for example, the trench 7 of the second embodiment, in which case the trench 7 is completely filled with the heat-shrinkable material 5.

Fourth embodiment

Referring to fig. 4(a), in this embodiment, the heat shrinkable material 5 completely seals the side surfaces of the LED chip 2 and the light emitting surface thereof, and the pressing force thereof is larger. And, the two

convex mirror structures

8, 9 of the thermal contraction material 5 are symmetrical along the center of the LED chip 2, and the

convex mirror structures

8, 9 can increase the light-emitting rate and prevent the brightness difference between the central light and the edge light from being larger. In this embodiment, the heat shrinkable material 5 is a transparent material. Referring to fig. 4(b), at this time, the fluorescent resin 6 covers the heat shrinkable material 5. Of course, in this embodiment, it is also possible to have, for example, the trench 7 of the second embodiment, in which case the trench 7 is completely filled with the heat-shrinkable material 5.

Fifth embodiment

Referring to fig. 5(a), in this embodiment, the structure of the heat shrinkable material 5 is the same as that of the first embodiment, and is not described again. However, the fluorescent resin 6 covers the heat shrinkable material 5 and the light emitting surface. The fluorescent resin 6 has a convex arc surface (i.e., a convex structure) which can increase the light extraction rate.

The invention also provides a manufacturing method of the energy-saving LED lighting device, which comprises the following steps:

(1) fixing an LED chip on the substrate by using an adhesive layer;

Of course, the above method may be applied to the first to fifth embodiments, and the specific details and processes thereof may be different, as will be understood by those skilled in the art herein.

Finally, it should be noted that: it should be understood that the above examples are only for clearly illustrating the present invention and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the scope of the invention.

Claims

1. An energy efficient LED lighting device, comprising:

a substrate having a circuit layer;

a bonding wire electrically connecting the electrode and the circuit layer;

the heat shrinkage material completely seals the welding wires and the electrodes, and the heat shrinkage material completely seals the light emitting surface of the LED chip;

a fluorescent resin completely sealing the heat shrinkable material;

wherein the thermal contraction material is provided with two convex mirror structures which are symmetrical along the center of the LED chip;

and the heat shrinkable material is selected from polyvinylidene chloride, polyvinyl chloride, PET or polyester resin material, which is transparent material.

2. The energy-saving LED lighting device according to claim 1, wherein: the substrate is provided with a groove around the LED chip, and the heat shrinkage material at least fills a part of the groove.

3. The energy-saving LED lighting device according to claim 2, wherein: the fluorescent resin fills another portion of the groove.

4. A method for manufacturing an energy-saving LED lighting device, which is used for manufacturing the energy-saving LED lighting device according to any one of claims 1 to 3, comprising:

(1) fixing an LED chip on the substrate by using an adhesive layer;

(3) dispensing and curing to form a heat-shrinkable material, wherein the heat-shrinkable material completely seals the bonding wires and the electrodes, and the heat-shrinkable material completely seals the light-emitting surface of the LED chip;

(4) injection molding to form a fluorescent resin, wherein the fluorescent resin completely seals the heat shrinkable material;