TWI455370B - Led and the manufacturing method thereof - Google Patents

Description

Light-emitting diode manufacturing method

The invention relates to a light emitting diode and a manufacturing method thereof.

LED (Light Emitting Diode) industry is one of the most watched industries in recent years. Since its development, LED products have been energy-saving, energy-saving, high efficiency, fast response time and long life cycle. It does not contain mercury and has environmental benefits. It has been used in lighting applications.

The existing light-emitting diodes have the characteristics of high color rendering of the light-emitting diode package structure, and generally adopt a structure of a blue light source, a red phosphor powder, and a green phosphor powder. However, the red fluorescing powder is generally less excited than the green fluorescing powder. If the red fluorescing powder and the green fluorescing powder are uniformly mixed in the encapsulant, it is easy to have a problem of more green than red. The color of the LED light is deviated, which affects its light output.

In view of the above, the present invention provides a method of fabricating a light-emitting diode that can alleviate the phenomenon of deviation in light color.

A method for fabricating a light-emitting diode, comprising the steps of: providing a substrate comprising an electrode layer attached to a surface thereof, a reflective cup formed on an upper surface thereof, and a channel extending through the upper and lower surfaces thereof, the reflective cup being centrally Forming one up An open recessed cup; an LED chip is disposed in the concave cup, the substrate, the reflective cup and the LED chip together form a bearing structure; forming a first encapsulation layer on the reflective cup, the first encapsulation layer is doped a phosphor powder, the first encapsulation layer covers the concave cup and leaves a space between the substrate; and the fluid material is injected into the concave cup through the channel to form a second encapsulation layer, the second encapsulation layer is doped with the second phosphor powder, The excitation efficiency of the second phosphor is higher than the excitation efficiency of the first phosphor.

Since the first phosphor powder and the second phosphor powder are respectively doped in the first encapsulating layer and the second encapsulating layer, when the first phosphor powder and the second phosphor powder have different excitation efficiencies, Different illumination is given because of the different distances from the wafer. Therefore, by adjusting the distance between the first encapsulation layer and the second encapsulation layer relative to the wafer, the problem of uneven excitation of the two types of phosphor powder can be effectively improved, and the deviation phenomenon of the color of the light-emitting diode can be reduced.

10‧‧‧Substrate

11‧‧‧ channel

20‧‧‧electrode layer

21‧‧‧First electrode

22‧‧‧second electrode

30‧‧‧Reflection Cup

31‧‧‧ concave cup

40‧‧‧ wafer

41‧‧‧Wire

50‧‧‧First encapsulation layer

51‧‧‧First Fluorescent Powder

60‧‧‧Second encapsulation layer

61‧‧‧Second Fluorescent Powder

70, 80‧‧‧Lighting diodes

100‧‧‧bearing structure

501‧‧‧ first surface

502‧‧‧ second surface

1 is a first step of a method of fabricating a light-emitting diode according to a first embodiment of the present invention.

2 is a plan view showing a first step of the method of fabricating the light-emitting diode of FIG. 1.

3 is a second step of a method of fabricating a light-emitting diode according to a first embodiment of the present invention.

4 is a third step of a method of fabricating a light-emitting diode according to a first embodiment of the present invention.

FIG. 5 is a fourth step of a method of fabricating a light-emitting diode according to a first embodiment of the present invention.

FIG. 6 is a fifth step of the method of fabricating the light-emitting diode according to the first embodiment of the present invention.

Fig. 7 is a schematic view showing a light-emitting diode of a second embodiment of the present invention.

Referring to FIG. 1-6, a method for fabricating the photodiode 70 of the first embodiment of the present invention To include the following steps:

Step 1: As shown in FIG. 1-2, a substrate 10 is provided, which is in the shape of a rectangular plate. The substrate 10 is made of ceramic, plastic or other insulating material. An electrode layer 20 is attached to the upper surface of the substrate 10, and is separated by a gap into a first electrode 21 and a second electrode 22 which are insulated from each other. The first electrode 21 and the second electrode 22 are respectively protruded from opposite ends of the substrate 10 in the horizontal extending direction, and are connected to an external power source as an electrode of the light-emitting diode 70. A reflective cup 30 is formed on the substrate 10. The reflector cup 30 has an annular shape, and a concave cup 31 whose upper end is open and slightly enlarged from the substrate 10 toward the opening is formed therebetween, and a part of the substrate 10, the first electrode 21, and the second electrode 22 is exposed from the concave cup 31. . The inner surface of the reflector cup 30, that is, the surface surrounding the concave cup 31 is plated with a high reflectivity material. The substrate 10 includes at least two channels 11 extending through the upper and lower surfaces thereof. In the present embodiment, the substrate 10 includes four channels 11. The four channels 11 are distributed on portions of the substrate 10 corresponding to the concave cups 31, and are vertically opened from the upper surface of the substrate 10 to the lower surface. Of course, the channel 11 is not limited to being perpendicular to the surface of the substrate 10 as long as it can penetrate the lower surface of the substrate 10 and the concave cup 31. The extension of the electrode layer 20 avoids the four channels 11.

Step 2: As shown in FIG. 3, an LED chip 40 is mounted in the concave cup 31, and electrically connected to the first electrode 21 and the second electrode 22. The LED chip 40 can be electrically connected to the first electrode 21 and the second electrode 22 by eutectic or flip chip. In this embodiment, the LED chip 40 is mounted on the first electrode 21, and the plurality of wires 41 are electrically connected to the first electrode 21 and the second electrode 22, thereby forming a light-emitting diode carrier. Structure 100. The height of the wafer 40 is not higher than the height of the reflective cup 30.

Step 3: As shown in FIG. 4, a first encapsulation layer 50 is provided, which is made of a resin material (Resin), Silicone (Silicone), a polymer (Polymer), and a sub-layer. Cree, polymethyl methacrylate (PMMA) or plastic. The first encapsulation layer 50 is a fluorescent film doped with a first phosphor powder 51. In this embodiment, the first phosphor powder 51 is a red phosphor powder, such as a nitride phosphor powder. The first encapsulation layer 50 can be formed by injection molding having opposing first and second surfaces 501, 502. The carrier structure 100 is inverted such that the wafer 40 is opposed to the first encapsulation layer 50, that is, the reflective cup 30 is located below and the substrate 10 is positioned above. Before the first encapsulation layer 50 is cured, the inverted carrier structure 100 is inserted into the first encapsulation layer 50 from the second surface 502 of the first encapsulation layer 50, so that the first encapsulation layer 50 covers the reflective cup 30 away from the substrate 10 . One end. The second surface 502 is spaced apart from the substrate 10 such that a space is left between the first encapsulation layer 50 and the substrate 10 to accommodate the wafer 40. That is, the first encapsulation layer 50 is not in contact with the wafer 40. Since the first encapsulation layer 40 is formed by injection molding and combined with the reflective cup 30 before curing, the first surface 501 is always maintained in a plane, which avoids the occurrence of concave or convex surfaces due to factors of the packaging material itself. Due to the flat shape of the first encapsulating layer 50, the uniformity of the first phosphor powder 51 is ensured, and the light has a good emission effect after passing through the first encapsulating layer 50.

Step 4: As shown in FIG. 5, after the first encapsulation layer 50 is cured, a fluid material is injected from the channel 11 into the concave cup 31 to form a second encapsulation layer 60. The fluid material is injected from one, two or three channels 11 into the space of the concave cup 31 sandwiched by the first encapsulation layer 50 and the substrate 10, and is discharged from the remaining three, two or one passages 11 into the space. air. The second encapsulation layer 60 covers the wafer 40 and has a smaller thickness than the first encapsulation layer 50. The second encapsulating layer 60 includes a second phosphor powder 61 therein. The second phosphor 61 has an excitation efficiency greater than that of the first phosphor 51. In this embodiment, the second phosphor 61 is a green phosphor, such as oxynitride phosphor. After the second encapsulation layer 60 is formed, the excess portion of the first encapsulation layer 50 covering the outer side of the reflective cup 30 is removed, and the light-emitting diode 70 of the present embodiment can be fabricated.

Referring again to FIG. 6, a schematic diagram of the completed light emitting diode 70 of the first embodiment is shown. The light emitting diode 70 includes a substrate 10 , an electrode layer 20 , a reflective cup 30 , a wafer 40 , a first encapsulation layer 50 , and a second encapsulation layer 60 . The wafer 40 is mounted in a concave cup 31 surrounded by a reflector cup 30. The substrate 10 includes a channel 11 that extends through the substrate 10 and communicates with the concave cup 31. The second encapsulation layer 60 covers the wafer 40 , and the height of the second encapsulation layer 60 is shorter than the height of the reflective cup 30 . The first encapsulation layer 50 fills the concave cup 31 and covers the upper surface of the second encapsulation layer 60 and the upper end of the reflective cup 30 , and the thickness of the first encapsulation layer 50 is greater than the thickness of the second encapsulation layer 60 . The first encapsulating layer 50 is doped with a first phosphor powder 51, and the second encapsulating layer 60 is doped with a second phosphor powder 61. The second phosphor powder 61 has an excitation efficiency greater than the first phosphor Powder 51. The first encapsulation layer 50 forms a flat first surface 501, and the first surface 501 is a light-emitting surface of the LED body 70. Since the first encapsulation layer 50 has been formed into a fluorescent film by injection molding before being combined with the reflective cup 30, and the first encapsulation layer 50 is combined with the reflective cup 30 by the second surface 502 thereof, the first surface 501 is always maintained. smooth. That is to say, the light-emitting diode 70 produced by the above method has a flat light-emitting surface. And since the first encapsulation layer 50 and the second encapsulation layer 60 are formed in two steps, the first phosphor powder 51 doped in the two encapsulation layers 50, 60 and the second phosphor powder 61 are not mixed. Moreover, since the second phosphor powder 61 doped on the second encapsulation layer 60 covering the surface of the wafer 40 has higher excitation efficiency, the first phosphor powder 51 having lower excitation efficiency is disposed in the first encapsulation layer 50. The second phosphor powder 61 with higher excitation efficiency is disposed in the second encapsulation layer 60, and the thickness of the first encapsulation layer 50 is greater than the thickness of the second encapsulation layer 60. In this way, the first phosphor powder 51 having a lower excitation efficiency can be subjected to a larger excitation region and the first phosphor powder 51 is also excited by the light emitted from the second phosphor powder 61, thereby enabling The color of the light emitting diode 70 is relatively uniform, and is suitable for use in a lighting device with high color rendering.

Referring again to FIG. 7, a schematic diagram of the completed light emitting diode 80 of the second embodiment is shown. The first four steps of the manufacturing method of the light-emitting diode 80 of the present embodiment are completely the same as the four steps of the manufacturing method of the light-emitting diode 70 of the previous embodiment, and the difference is that the light-emitting diode of the embodiment The method for manufacturing the body 80 further includes step five. When the second encapsulation layer 60 is not cured, the second phosphor powder 61 is formed into an arc structure by a centrifugation process. Since the second phosphor powder 61 in the second encapsulation layer 60 has a specific gravity larger than that of the colloid, the second phosphor powder 61 is deposited on the bottom of the concave cup 31, that is, the surface of the substrate 10, adjacent to the concave cup 31 after the centrifugation process. More second phosphor 61 is deposited at the location of the inner periphery. Therefore, the second phosphor powder 61 is attached to the bottom of the concave cup 31 by an arc shape having an intermediate depression after the centrifugation process. The second phosphor 61 is attached to the bottom of the concave cup 31, and the arc shape of the recess formed by the second phosphor 61 does not cover the upper side of the wafer 40. Because the forward direction of the wafer 40, that is, the luminous flux of the upper light emitting is greater than the luminous flux of the lateral light emitting, the second fluorescent powder 61 does not cover the upper surface of the wafer 40, thereby reducing the excitation of the second fluorescent powder 61 by the light. The excitation efficiency of the first phosphor 51 is increased, so that the second phosphor 61 having higher excitation efficiency and the first phosphor 51 having lower excitation efficiency are mixed with light of a more uniform color. And since the second phosphor 61 has a concave arc shape, when the light is emitted from the concave surface to the first encapsulation layer 50, the concave arc surface can diverge the light emitted from the second phosphor 61 to A larger divergence angle is incident on the first encapsulation layer 50 to better excite the first phosphor powder 51.

The LEDs 70 and 80 of the above two embodiments each include a first encapsulation layer 50 and a second encapsulation layer 60. The first encapsulation layer 50 is doped with a first phosphor powder 51 having a lower excitation efficiency. The second encapsulation layer 60 is doped with a second phosphor powder 61 having a higher excitation efficiency, and the first encapsulation layer 50 is thicker, and the second encapsulation layer 60 is closer to the wafer 40. Thereby, the first phosphor powder 51 can be better excited, and the light mixture with the second phosphor powder 61 is more uniform, so that the light-emitting diodes 70, 80 emit light uniformly.

10‧‧‧Substrate

11‧‧‧ channel

20‧‧‧electrode layer

40‧‧‧ wafer

50‧‧‧First encapsulation layer

60‧‧‧Second encapsulation layer

61‧‧‧Second Fluorescent Powder

501‧‧‧ first surface

Claims (9)

A method for fabricating a light-emitting diode, comprising the steps of: providing a substrate comprising an electrode layer attached to a surface thereof, a reflective cup formed on an upper surface thereof, and a channel extending through the upper and lower surfaces thereof, the reflective cup being centrally Forming an upwardly open concave cup; providing an LED chip in the concave cup, the substrate, the reflective cup and the LED chip together form a bearing structure; forming a first encapsulation layer on the reflective cup, the first package The layer is doped with the first phosphor powder, the first encapsulation layer covers the concave cup and leaves a space between the substrate; after the first encapsulation layer is cured, passes through the channel to the space between the first encapsulation layer and the substrate The fluid material is injected to form a second encapsulation layer, the second encapsulation layer is doped with a second phosphor powder, and the excitation efficiency of the second phosphor powder is higher than the excitation efficiency of the first phosphor powder. The method for fabricating a light-emitting diode according to claim 1, wherein the thickness of the first encapsulation layer is greater than the thickness of the second encapsulation layer. The method for fabricating a light-emitting diode according to claim 2, wherein the second encapsulation layer covers the wafer. The method for fabricating a light-emitting diode according to claim 1, wherein the first encapsulation layer is disposed before the reflective cup as an uncured fluorescent film having a flat first surface and a second surface. . The method for fabricating a light-emitting diode according to claim 4, wherein the first encapsulating layer is disposed on the open end of the reflecting cup by inverting the carrying structure, inserting the reflecting cup into the second surface. The method for fabricating a light-emitting diode according to claim 1, wherein the first phosphor powder is a red phosphor powder, and the second phosphor powder is a green phosphor powder. The method for fabricating a light-emitting diode according to claim 1, wherein: after injecting the fluid material, the light-emitting diode is deposited on the substrate by a centrifugal process before the fluid material is cured. surface. The method for fabricating a light-emitting diode according to claim 7, wherein the second phosphor has an arc shape that is recessed in the direction of the substrate and does not cover the LED chip. The method for fabricating a light-emitting diode according to claim 7, wherein the thickness of the second phosphor is gradually increased from a position near the LED wafer to a position close to the reflective cup.