KR20060124515A - Light emitting diode package and method for manufacturing the same - Google Patents

Abstract

An LED package is provided to reduce optical loss and to emit light in one direction by reversely reflecting the light emitted from an LED device through a reflection surface of a curved surface type. A groove part is formed in the upper surface of a metal substrate(101) and a reflection surface(101a) of a concavely curved type is formed on the bottom of the groove part. A plurality of leadframes(104,106) have leads(104b,106b) withdrawn to the upper part of the groove part, installed on the metal substrate. At least one LED device(50) is mounted on the lower surface of the lead to confront the reflection surface. A molding part is formed in the groove part to package the LED device. The leadframe is extended to the lower surface of the metal substrate along the outer circumferential surface of the metal substrate.

Description

LIGHT EMITTING DIODE PACKAGE AND METHOD FOR MANUFACTURING THE SAME

1 is a cross-sectional view of a conventional light emitting diode package.

2 is a cross-sectional view of a light emitting diode package according to an embodiment of the present invention.

3 is a plan view of the LED package of FIG. 2.

4 is a cross-sectional view of a light emitting diode package according to another embodiment of the present invention.

5 is a plan view of the LED package of FIG. 4.

6 is a cross-sectional view of a light emitting diode package according to another embodiment of the present invention.

7 to 11 are cross-sectional views illustrating a method of manufacturing the light emitting diode package of FIG. 4.

<Description of the symbols for the main parts of the drawings>

100: light emitting diode package 50: LED device

51: bonding wire 60: phosphor film

70: transparent molding resin 101: metal substrate

101a: reflecting surfaces 104, 106: lead frame

104a, 106a: heat dissipation hole 104b, 106b: lead

The present invention relates to a light emitting diode package and a method for manufacturing the same, and more particularly, to a light emitting diode package suitable for realizing a uniform surface light source with excellent heat emission characteristics and a method for manufacturing the same.

Recently, light emitting diodes (LEDs) are used as light sources of various colors. In particular, as the demand for high-power, high-brightness LEDs for lighting LED lights increases, a lot of heat is generated in the LED device. In order to prevent deterioration of the device's characteristics and shortening its lifetime, heat generated in the LED device must be effectively released from the LED package. Therefore, efforts are being made to effectively dissipate heat generated from LED devices in high power LED packages.

In addition, as LED elements are used for white illumination, backlights, and the like, LED packages capable of outputting uniform white light with high brightness are required. In particular, in order to obtain high-quality white light, the output light should not deviate from the white region on the color coordinates, and should be viewed as a surface light source rather than a point light source.

1 is a cross-sectional view showing a schematic structure of a conventional white light LED package 10. Referring to FIG. 1, the LED package 10 includes a package body 7 having a reflection surface 7a and two lead frames 3 and 4. The package main body 7 is a resin molding obtained by injection molding. The blue LED element 1 is mounted on one lead frame 4 and wire-bonded to another lead frame 3 by wires 5. In the mounting area of the LED element 1, a molding part 8 for wrapping the LED element 5 and its connecting portion is formed. This molding part 8 is formed from the epoxy resin in which fluorescent substance is disperse | distributed.

During curing of the molding part 8 during the manufacturing process of the LED package 10, the phosphor is unevenly distributed in the epoxy resin. Accordingly, it is difficult to obtain uniform white light and excellent color coordinate characteristics with the LED package 10. In addition, since the package main body 7 is made of a resin material, heat dissipation characteristics are not good. Furthermore, since the light coming directly from the element 1 has a greater luminous intensity than the light reflected by the reflecting surface 7a, a point light source appears in the central portion of the LED package 10. Therefore, it is difficult to obtain a uniform surface light source. In order to improve the color coordinate characteristics, Korean Patent Laid-Open Publication No. 2004-0024747 discloses a reflective LED package having a phosphor film and a reflective layer on a lower surface of a molding resin. However, this reflective LED package mainly dissipates heat through the leads, resulting in poor heat dissipation.

In addition to the LED package 10, a white light LED package may be implemented using a red LED, a green LED, and a blue LED. However, even in a conventional LED package that implements white light using red, green, and blue LEDs, the output light is not uniform because the three primary colors output from each LED are not completely mixed, and a point light source of a partial individual color is generated. The problem of the point light source occurs not only in a white light LED package but also in an LED package emitting individual colors such as a blue LED package.

The present invention has been made to solve the above problems, an object of the present invention is to provide an LED package that can effectively emit heat generated from the LED element and implement a uniform surface light source.

Further, another object of the present invention is to provide a method of manufacturing an LED package having excellent heat dissipation characteristics and exhibiting uniform surface light source characteristics.

In order to achieve the above technical problem, the LED package according to the present invention,

A metal substrate having a groove formed on an upper surface thereof, and a reflecting surface having a concave curved surface formed on the bottom of the groove; A plurality of lead frames provided on the metal substrate and having leads drawn out onto the grooves; One or more LED elements mounted on a bottom surface of the lead to face the reflective surface; It is formed in the groove portion includes a molding unit for packaging the LED device. The lead frame extends along the outer circumferential surface of the metal substrate to the bottom surface of the metal substrate.

Preferably, the metal substrate is an aluminum substrate. An insulating film may be formed between the metal substrate and the lead frame to insulate the lead frame from the metal substrate. In this case, the insulating film is preferably an aluminum oxide film obtained by anodization.

Preferably, the lead frame is formed with a plurality of heat dissipation holes penetrating the lead frame. These heat dissipation holes further improve heat dissipation characteristics of the LED package.

According to one embodiment of the invention, the plurality of lead frames includes a first lead frame having a first lead on which the LED element is mounted, and a second lead frame having a second lead wire-bonded with the LED element. The molding part includes a transparent resin formed on the reflective surface.

According to another embodiment of the present invention, the plurality of lead frames includes a first lead frame having a first lead on which the LED element is mounted, and a second lead frame having a second lead wire bonded to the LED element. A phosphor film is formed on the reflective surface, and the molding part includes a transparent resin formed on the phosphor film. In this case, the LED package may be a white light LED package. For example, a white light LED package may be implemented by using a blue LED device as the LED device and using a YAG-based phosphor film as the phosphor film. The phosphor film may include a mixture of phosphor and a transparent resin.

According to the above embodiments, when the LED element is a horizontal LED element, the LED element may be wire bonded to the first lead.

According to still another embodiment of the present invention, the plurality of lead frames includes a first lead frame having a first lead mounted with a red LED element, a second lead frame having a lead mounted with a green LED element, and a blue LED. And a third lead frame having a third lead on which the element is mounted, and a fourth lead frame having a fourth lead as a common electrode. In this case, the red, green, and blue LEDs are wire bonded to the fourth lead. In addition, the molding part includes a transparent resin formed on the reflective surface.

In order to achieve the other object of the present invention, the manufacturing method of the LED package according to the present invention,

Mounting the LED elements on each of the leads of at least one lead frame and wire bonding the LED elements to the leads of another lead frame; Preparing a metal substrate having a groove formed on an upper surface thereof and a reflecting surface of a concave curved surface formed on a bottom of the groove portion; Installing the lead frame on the metal substrate such that the LED element faces the reflective surface; And forming a molding part for packaging the LED device in the groove part.

Preferably, the metal substrate is made of aluminum. After preparing the metal substrate, the method may further include forming an insulating layer between the metal substrate and the lead frame to insulate the lead frame from the metal substrate. In this case, the insulating film may be formed by anodizing the surface of the metal substrate.

Preferably, a heat radiation hole is formed in the lead frame. By forming these heat dissipation holes, the heat dissipation characteristics of the LED package are further improved.

According to one embodiment of the invention, in the wire bonding step, the LED element is mounted on a lead of one lead frame and the LED element is wire bonded to a lead of the other lead frame. In the forming of the molding part, a transparent resin filling the groove part is formed on the reflective surface.

According to another embodiment of the present invention, in the wire bonding step, the LED element is mounted on a lead of one lead frame and the LED element is wire bonded to a lead of the other lead frame. The method may further include forming a phosphor film on the reflective surface after installing the lead frame. In this case, in the forming of the molding part, a transparent resin filling the groove part is formed on the phosphor film. The LED package may be a white light LED package.

The forming of the phosphor film may include depositing a phosphor on the reflective surface using a phosphor target. Alternatively, the forming of the phosphor film may include coating a mixture of phosphor and resin on the reflective surface.

According to another embodiment of the present invention, in the wire bonding step, a red LED is mounted on the lead of the first lead frame, a green LED is mounted on the lead of the second lead frame, and the lead of the third lead frame is mounted. The blue LED is mounted, and the red, green, and blue LEDs are wire-bonded to the lead of the fourth lead frame. In the forming of the molding part, a transparent resin filling the groove part is formed on the reflective surface.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

2 is a cross-sectional view of the LED package according to an embodiment of the present invention, Figure 3 is a plan view of the LED package of FIG. 2 is a cross-sectional view taken along the line XX ′ of FIG. 3. 2 and 3, the LED package 100 includes an aluminum substrate 101, two lead frames 104 and 1065, and an LED element 50. A hemispherical groove is formed in the upper surface of the aluminum substrate 101, and a concave curved reflective surface 101a is formed in the bottom of the groove. On the surface of the aluminum substrate 101 except for the reflective surface 101a, anodized aluminum oxide film 108 is formed to insulate the lead frames 104 and 106 from the aluminum substrate 101. In order to increase the reflectance, the reflecting surface 101a is mirror polished.

Two lead frames 104 and 106 are provided on the aluminum substrate 101 and extend along the outer circumferential surface of the substrate 101 to the lower surface of the substrate 101. The light exit side of the LED element 50 is mounted on the bottom surface of the lead 106b of the lead frame 106 so as to face the reflecting surface 101a. This LED element 50 is connected to the lead 104b of the other lead frame 104 by the wire 51. As shown in FIG. The groove portion is filled with a molding portion 60 made of a transparent resin such as epoxy resin or silicone resin to wrap the LED element 50 and the wire 51.

The LED package 100 may easily emit heat through the aluminum substrate 101 made of a metal material. 2 and 3, the lead frames 104 and 105 are directly exposed to air. Furthermore, a plurality of heat dissipation holes 104a and 106a penetrate the lead frames 104 and 105. Therefore, by increasing the heat dissipation into the air, the heat dissipation characteristics of the LED package 100 is further improved.

The light emitted from the LED device 50 is reflected through the reflecting surface 101a to emit light upward. By using this retroreflection, light loss is reduced and light is emitted in one direction. In addition, since the light coming out of the LED package 100 is the light reflected through the reflective surface 101a, a uniform surface light source is obtained without a point light source.

4 is a cross-sectional view of an LED package according to another embodiment of the present invention, and FIG. 5 is a plan view of the LED package of FIG. 4. 4 is a cross-sectional view taken along the line YY ′ of FIG. 5. The LED package 200 of this embodiment is the same as the LED package 100 of the above-mentioned embodiment except that the phosphor film 60 of uniform thickness is formed on the reflecting surface 101a. The LED package 200 is an LED package 200 that outputs white light.

4 and 5, the LED element 50 mounted on the bottom surface of the lead 106b is an LED element emitting blue light. On the reflective surface 101a, a phosphor film 60 for converting blue light into yellow is coated. The phosphor film 60 may include, for example, a YAG-based phosphor. The phosphor film 60 may be coated on the reflective surface 101a by vapor deposition using a phosphor target. Alternatively, the phosphor film 60 may be formed by applying a mixture of phosphor and resin (such as epoxy or silicone resin) to the reflective surface. On the phosphor film 60, a molding part 70 made of a transparent resin is formed. Since other components are the same as the above-described embodiment, detailed description is omitted.

In the LED package 200, unlike the conventional white light LED package (see reference numeral 10 of FIG. 1), since the phosphor is present in the phosphor film 60 formed on the reflecting surface 101a, the reflecting surface 101a is reflected. The resulting light exhibits uniform white light. In addition, since the nonuniformity of the output wavelength due to the nonuniform distribution of the phosphor is small, the color coordinate characteristic of the output light is improved.

6 is a cross-sectional view of an LED package according to another embodiment of the present invention. The LED package 300 uses red (R), green (G) and blue (B) LED elements 307, 317, and 327 to implement white light. As shown in FIG. 6, the LED package 300 includes four lead frames 304, 314, 324, 334. Heat dissipation holes 304a, 314a, 324a, and 334a are formed in each lead frame 304, 314, 324, and 334, and each lead frame includes leads 304b, 314b, 324b, and 334b drawn out into grooves. . A red (R) LED element 307 is mounted on the lower surface of the lead 304b, a green (G) LED element 317 is mounted on the lower surface of the lead 314b, and a blue (B) LED element is mounted on the lower surface of the lead 324b. 327 is mounted. Each LED element is wire bonded to the lead 334b. The wire bonded lead 334b becomes the common electrode C. FIG. Since other components are the same as the LED package 100 described above with reference to FIGS. 2 and 4, detailed description thereof will be omitted.

According to the LED package 300, each light emitted from each LED element is reflected at the reflecting surface 101a and completely mixed with each other. Thus, point light sources of partial individual colors do not appear, and a uniform white surface light source having excellent color coordinate characteristics is obtained.

In the above embodiments, one bonding wire was used for each LED element. This is because the LED device is a vertical LED device. However, when the LED element is a horizontal LED element, two bonding wires can be used for each LED element. For example, when the LED device 50 is a horizontal LED device in FIG. 2, the LED device 50 may be wire bonded to the lead 104b as well as the lead 106b.

Hereinafter, a method of manufacturing an LED package according to an embodiment of the present invention will be described with reference to FIGS. 7 to 11. This manufacturing method corresponds to the manufacturing method of the LED package 200 shown in FIGS.

First, referring to FIG. 7, the LED element 50 is mounted on the lead 106b of the lead frame 106 and wire-bonded to the lead 104b of the other lead frame 104 using the wire 51. . The LED device 50 may be, for example, a GaN-based LED that outputs blue light. Preferably, the lead frames 104 and 106 are manufactured by plating Ag (silver) or Au (gold) on the copper plate surface. The heat dissipation holes 104a and 106a are drilled through the lead frames 104 and 106.

Next, as shown in FIG. 8, the aluminum substrate 101 which has the reflecting surface 101a is prepared. Thereafter, anodization treatment is performed on the surface of the substrate 101 except for the reflective surface 101a to form an aluminum oxide film (aluite film) 108 on the surface of the substrate 101. This aluminum oxide film 108 exhibits insulation.

Next, as shown in FIG. 9, lead frames 104 and 106 coupled with the LED element 50 are installed on the aluminum substrate 101. At this time, the lead frame 104 is disposed so that the emission surface side of the LED element 50 faces the reflection surface 101a of the aluminum substrate 101 (that is, the LED element 50 faces the reflection surface 101a). 106). Thereafter, the lead frames 104 and 106 are cut and formed to fully bond the lead frames 104 and 106 to the aluminum substrate 01 as shown in FIG.

Next, as shown in FIG. 10, the phosphor film 60 is formed on the reflective surface 101a. The phosphor film 60 may include, for example, a YAG-based phosphor. The phosphor film 60 may be formed by depositing the target material on the reflective surface 101a using a phosphor target. Alternatively, the phosphor film 60 may be formed by applying a silicon or epoxy resin mixed with phosphors on the reflective surface 101a. For example, the phosphor film 60 may be formed by injecting a mixture of the phosphor and the resin into the reflective surface using a dispenser.

Next, as shown in FIG. 11, by forming a transparent resin on the phosphor film 60, the molding part 70 filling the groove part is formed. For example, the molding part 70 filling the groove part may be formed using an epoxy resin or a silicone resin. Accordingly, the LED package 200 of FIG. 4 capable of outputting white light is completed.

It is intended that the invention not be limited by the foregoing embodiments and the accompanying drawings, but rather by the claims appended hereto. In addition, it will be apparent to those skilled in the art that the present invention may be substituted, modified, and changed in various forms without departing from the technical spirit of the present invention described in the claims.

As described above, according to the present invention, by reflecting the light emitted from the LED device through the curved reflecting surface, the light loss can be reduced and light can be emitted in one direction, and a uniform surface light source can be realized. do. Excellent heat dissipation is achieved by using a metal substrate. In particular, by forming the heat radiation holes in the lead frame, the heat radiation characteristics are further improved. In addition, uniform white light with improved color coordinate characteristics can be easily obtained.

Claims (23)

A metal substrate having a groove formed on an upper surface thereof, and a reflecting surface having a concave curved surface formed on the bottom of the groove; A plurality of lead frames provided on the metal substrate and having leads drawn out onto the grooves; One or more LED elements mounted on a bottom surface of the lead to face the reflective surface; The light emitting diode package is formed in the groove portion comprising a molding unit for wrapping the LED element. The method of claim 1, The lead frame extends to the lower surface of the metal substrate along an outer circumferential surface of the metal substrate. The method of claim 1, The metal substrate is a light emitting diode package, characterized in that the aluminum substrate. The method of claim 3, An insulating film for insulating the lead frame from the metal substrate is formed between the metal substrate and the lead frame. The method of claim 4, wherein The insulating film is a light emitting diode package, characterized in that the aluminum oxide film obtained by anodizing the surface of the metal substrate. The method of claim 1, The lead frame has a heat dissipation hole formed in the lead frame, characterized in that the LED package. The method of claim 1, The plurality of lead frames includes a first lead frame having a first lead on which the LED element is mounted, and a second lead frame having a second lead wire-bonded with the LED element, The molding unit comprises a transparent resin formed on the reflective surface. The method of claim 1, The plurality of lead frames includes a first lead frame having a first lead on which the LED element is mounted, and a second lead frame having a second lead wire-bonded with the LED element, Phosphor film is formed on the reflective surface, The molding unit comprises a transparent resin formed on the phosphor film. The method of claim 8, The LED package is a light emitting diode package, characterized in that the white light emitting diode package. The method of claim 9, The LED device is a blue LED device, The phosphor film is a light emitting diode package comprising a YAG-based phosphor. The method of claim 8, The phosphor film is a light emitting diode package comprising a mixture of phosphor and a transparent resin. The method according to claim 7 or 8, The LED device is a horizontal LED device, The LED device is a light emitting diode package, characterized in that the wire lead is also bonded to the first lead. The method of claim 1, The plurality of lead frames may include a first lead frame having a first lead mounted with a red LED element, a second lead frame having a lead mounted with a green LED element, and a third lead mounted with a blue LED element. A fourth lead frame having a third lead frame and a fourth lead as a common electrode, The red, green and blue LEDs are wire bonded to the fourth lead, The red, green and blue LEDs are disposed to face the reflective surface, The molding unit comprises a transparent resin formed on the reflective surface. Mounting the LED elements on each of the leads of at least one lead frame and wire bonding the LED elements to the leads of another lead frame; Preparing a metal substrate having a groove formed on an upper surface thereof and a reflecting surface of a concave curved surface formed on a bottom of the groove portion; Installing the lead frame on the metal substrate such that the LED element faces the reflective surface; Forming a molding portion for packaging the LED element in the groove portion manufacturing method of a light emitting diode package comprising the. The method of claim 14, The metal substrate is a method of manufacturing a light emitting diode package, characterized in that made of aluminum. The method of claim 15, And after preparing the metal substrate, forming an insulating film between the metal substrate and the lead frame to insulate the lead frame from the metal substrate. The method of claim 16, And the insulating film is formed by anodizing the surface of the metal substrate. The method of claim 14, And a heat dissipation hole is formed in the lead frame. The method of claim 14, In the wire bonding step, mounting the LED element to a lead of one lead frame and wire bonding the LED element to a lead of another lead frame, In the forming of the molding part, a method of manufacturing a light emitting diode package, characterized in that to form a transparent resin filling the groove portion on the reflective surface. The method of claim 14, In the wire bonding step, mounting the LED element to a lead of one lead frame and wire bonding the LED element to a lead of another lead frame, Forming a phosphor film on the reflective surface after installing the lead frame; In the forming of the molding part, a method of manufacturing a light emitting diode package, characterized in that to form a transparent resin filling the groove portion on the phosphor film. The method of claim 20, The forming of the phosphor film may include depositing a phosphor on the reflective surface using a phosphor target. The method of claim 20, The forming of the phosphor film may include coating a mixture of phosphor and a resin on the reflective surface. The method of claim 14, In the wire bonding step, the red LED is mounted on the lead of the first lead frame, the green LED is mounted on the lead of the second lead frame, the blue LED is mounted on the lead of the third lead frame, and the fourth lead frame is mounted. Wire-bond the red, green and blue LEDs to the lead of In the forming of the molding portion, a method of manufacturing a light emitting diode package, characterized in that to form a transparent resin filling the groove portion on the reflective surface.

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