KR101589700B1 - Method for fabricating Light emitting diode package - Google Patents

Abstract

An LED package having LED and fluorescent film pieces, and a manufacturing method thereof are disclosed. The disclosed LED package includes a lead frame having an LED mounting groove with an open top surface, an LED (light emitting diode) mounted on the inner surface of the LED mounting groove and electrically connected to the lead frame, An encapsulant to be cured, and a piece of fluorescent film formed by screen-printing a fluorescent ink, which is adhered to the upper surface of the sealing resin without an adhesive medium.

Description

[0001] The present invention relates to a method of fabricating an LED package,

The present invention relates to an LED package having an LED and a fluorescent film piece, and a manufacturing method thereof.

BACKGROUND ART An LED package used as an indicator of an electronic device, a backlight unit of an LCD panel, a lighting device, or the like, typically mounts a light emitting diode (LED), which is a kind of semiconductor chip, on a lead frame, And is sealed with a light-transmitting resin to protect the electrode connection portion. As the encapsulant, a silicone resin mixed with a phosphor powder in powder form is generally used.

However, in such a conventional LED package, it is difficult to homogeneously stir and mix the fluorescent filler powder with the sealing resin, so that the deviation in the light emission characteristic of the LED package becomes large, so that quality control is difficult and the yield of good products is low. In addition, the heat generation of the LED deforms the fluorescent filler powder contained in the sealing resin to lower the luminous efficiency and shorten the lifetime of the LED package.

Korean Patent Publication No. 10-1102237 Korean Patent Publication No. 10-2011-0074098

The present invention provides an LED package in which a piece of fluorescent film formed by screen printing of a fluorescent ink is adhered to the upper side of a resin for light-transmitting sealing, and a method of manufacturing the LED package.

The present invention relates to a light emitting diode (LED), comprising: a lead frame having an LED mounting groove with an opened top surface; an LED (light emitting diode) mounted on an inner surface of the LED mounting groove and electrically connected to the lead frame; And a fluorescent film piece formed by screen-printing a fluorescent ink, which is adhered to the upper surface of the sealing resin without an intermediate medium for adhesion, is provided .

The LED package of the present invention may further comprise a transparent protective film piece laminated on the fluorescent film piece, wherein the protective film piece is formed of a silicone resin or an ultraviolet ray (UV) curable resin which is cured by infrared irradiation .

The piece of protective film is formed by screen printing on the piece of fluorescent film, and the flatness between the piece of fluorescent film and the piece of transparent protective film may be 1 to 5 탆.

The thickness of the fluorescent film piece may be 30 to 90 탆.

The fluorescent ink is formed to contain 25 to 60% by weight of a binder resin mixture containing a polyester resin, an acrylic resin, a cellulose resin and a diluent, 30 to 70% by weight of a fluorescent filler, and 5 to 20% .

The present invention also provides a method of manufacturing a light emitting device, comprising: an LED mounting step of mounting an LED on a lead frame having an LED mounting groove opened on an upper side thereof and electrically connecting a lead frame and an LED; A sealing resin filling step of filling and filling the resin, a fluorescent film piece forming step of screen printing a fluorescent ink on a base film to form a fluorescent film piece, a step of picking up the fluorescent film piece to be separated from the base film picking up a fluorescent film piece, placing the picked-up fluorescent film piece on the upper side of the sealing resin before the sealing resin injected into the LED mounting groove is completely cured, and And a curing step of completely curing the sealing resin to fix (adhere) the fluorescent film piece to the sealing resin. There is provided a method.

The step of forming the fluorescent film piece may include forming a protective film piece that forms a protective film piece on the fluorescent film piece by screen printing the silicone resin on the fluorescent film piece formed on the base film and curing at a temperature higher than room temperature or room temperature Step < / RTI >

Wherein the step of forming the fluorescent film piece comprises screen printing a transparent ultraviolet ray cured resin which is cured by infrared irradiation so as to overlap with the fluorescent film piece and irradiating infrared rays onto the UV cured resin to protect And a protective film piece forming step of forming a film piece.

The LED package of the present invention forms a fluorescent film piece by screen-printing a liquid fluorescent ink in which a fluorescent filler is homogeneously distributed, so that the thickness is uniform over the whole area of the fluorescent film piece and the flatness of the upper and lower sides is excellent Thus, the optical characteristics are homogeneous. Therefore, in the case of a specific color light emission application, the color deviation range is narrow, so that the yield of the good product is improved and the cost is reduced due to the improvement of the productivity.

In addition, unlike the case where the fluorescent filler powder directly touches or is located very close to the LED in the conventional case, since the fluorescent film pieces are sufficiently separated from the LEDs, thermal deformation of the fluorescent film pieces is small, Lt; / RTI >

1 is a cross-sectional view illustrating an LED package according to a first embodiment of the present invention.
FIGS. 2 to 5 sequentially illustrate the LED package manufacturing method of FIG. 1. FIG.

Hereinafter, an LED package and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom of the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

1 is a cross-sectional view illustrating a light emitting diode package according to a first embodiment of the present invention. Referring to FIG. 1, the LED package 1 according to the first embodiment of the present invention includes a lead frame ) 4, an LED 7, a sealing encapsulant 10, and a film carving assembly 11. The lead frame 4 has an upper side opened to form an LED mounting groove. The LED 7 is fixedly mounted on the inner bottom surface of the LED mounting groove and is electrically connected to the lead frame 4 by a bonding wire 8. The sealing resin 10 is filled in the LED mounting groove on which the LED 7 is mounted and cured. The sealing resin 10 may be, for example, an optically transparent silicone resin, and the liquid silicone resin 10 may be cured at room temperature or at a high temperature higher than room temperature, .

The film piece assembly 11 is attached to the upper surface of the sealing resin 10 without an adhesive medium such as OCA (optical clean adhesive), for example. Before the sealing resin 10 is completely cured, The resin 10 is attached to the upper surface of the sealing resin 10 and then is completely hardened to be fixed to the sealing resin 10. The film piece assembly 11 includes a fluorescent film piece 12 formed by screen printing a fluorescent ink and a transparent protective film piece 13 laminated to the fluorescent film piece 12. [ The fluorescent ink of the fluorescent film piece 12 improves the luminance of the light projected from the LED package 1. The protective film piece 13 may be formed of an ultraviolet (UV) curable resin that is cured by silicone resin or ultraviolet ray irradiation as a layer which suppresses physical damage of the fluorescent film piece 12. [

Since the fluorescent film piece 12 is formed by screen printing of a fluorescent ink containing no silicone resin, the fluorescent film piece 12 can be formed to have a thin thickness t of 30 to 90 탆, and the fluorescent film piece 12 The flatness of the upper surface of the LED package 1 is also excellent to 1 to 5 mu m, so that the optical characteristics of the light projected from the LED package 1 are improved. A method of manufacturing the LED package 10, including a method of forming the film piece assembly 11 including the fluorescent film pieces 12, will be described later.

The LED package 1 can project light of various colors according to the combination of the color of the light emitted from the LED 7 and the color of the film piece assembly 11, have. An LED 7 emitting white light and a transparent fluorescent film piece 12 may be combined so that the LED package 1 projects white light. However, the LED 7, which emits blue light, And the yellow fluorescent film piece 12 may be combined. In the latter case, the fluorescent film piece 12 has a fluorescent film piece 12 formed by screen-printing a liquid fluorescent ink in which a powdery fluorescent filler is homogeneously distributed. Therefore, The flatness of the side surface of the fluorescent film piece 12 which is uniform over the entire upper surface area of the LED package 1 and which is in contact with the protective film piece 13 is also excellent as 1 to 5 占 퐉, This deviation is small and uniform. The thickness t of the fluorescent film piece 12 is 30 to 90 탆, and more preferably 60 to 65 탆. Therefore, compared with a conventional LED package in which a powdery fluorescence filler is mixed with a sealing resin for sealing the LED, the LED package 1 of FIG. 1 has a narrow color deviation range of projected white light, Costs are reduced due to productivity improvements.

FIGS. 2 to 5 sequentially illustrate the LED package manufacturing method of FIG. 1. FIG. A method of manufacturing an LED package according to the present invention includes an LED mounting step, a sealing resin injecting step, a fluorescent film piece forming step, a fluorescent film piece picking step, a fluorescent film piece mounting step, and a curing step. 2, the LED mounting step includes mounting the LED 7 on the inner bottom surface of the LED mounting groove of the lead frame 4 and bonding the lead frame 4 and the LED 7 to the bonding wire 8) and electrically connected to each other. The LED 7 is mounted on each lead frame 4 while a carrier (not shown) on which a plurality of lead frames 4 are mounted is moved along a rail (not shown) bonding can be carried out at a high speed by using an automated wire bonding device.

The sealing resin injecting step is a step of injecting and filling a liquid transparent sealing resin 10 into the LED mounting groove on which the LED 7 is mounted. A liquid sealing resin 10 is filled in a sylinder 20 and aligned with the lead frame 4 and then a silicone resin is discharged in a predetermined amount to fill the sealing resin 10 in the LED mounting groove. The sealing resin 10 may be, for example, silicone resin.

Referring to FIG. 3, the fluorescent film piece forming step is a step of screen printing a fluorescent ink onto the base film 17 to form a fluorescent film piece 12. The fluorescent ink is a liquid coating material formed by mixing and stirring a binder resin mixture, a powdery fluorescent filler, and a solvent. The fluorescent filler is uniformly diffused and distributed in the binder resin mixture and does not sink despite gravity And has uniform optical characteristics. In the fluorescent ink, the binder resin mixture accounts for 25 to 60 wt%, the fluorescent filler accounts for 30 to 70 wt%, and the solvent accounts for 5 to 20 wt%. The binder resin mixture includes, for example, a polyester resin, an acrylic resin, a cellulose resin, and a diluent. Examples of fluorescent fillers include, but are not limited to, SDY555-7 and R625 from YANTAI SHIELD ADVANCED MATERIALS. Examples of the solvent include dimethyl cyclohexylamine, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, ethylene glycol monobutyl ether acetate, xylene, ethyl acetate, dipropylene glycol monomethyl ether, n-butyl acetate, Or a mixture thereof, but is not limited thereto.

The step of forming a fluorescent film piece is a step of screen printing and curing the fluorescent ink on the base film 17 to form the fluorescent film piece 12 on the base film 17. (For example, a circle, a rectangle, a curved rectangle, etc.) matching the shape of the inner circumferential surface of the side opening on the lead frame 4 (see Fig. 2) through the screen printing, Can be printed on the film (17). The printed fluorescent ink pattern is cured at room temperature or higher than room temperature to form a solidified fluorescent film piece 12.

The step of forming a fluorescent film piece further includes a protective film engraving step of forming a protective film piece 13 on the fluorescent film piece 12 formed on the base film 17 by screen printing. According to an embodiment of the protective film piece forming step, a liquid silicone resin is screen-printed on the base film 17 so as to overlap with the fluorescent film piece 12 after forming the fluorescent film piece 12, The protective film piece 13 overlapping with the fluorescent film piece 12 is formed by curing at a temperature. According to another example of the protective film piece forming step, a transparent UV (ultraviolet ray) curable resin, which is cured by ultraviolet ray irradiation after the fluorescent film piece 12 is formed, 12, and the protective film piece 13 overlapping with the fluorescent film piece 12 is formed by curing the infrared ray by irradiating the screen-printed UV curable resin. The protective film piece 13 formed by screen printing can be formed to have a thin and constant thickness by overlapping with the fluorescent film piece 12 in the same form as the fluorescent film piece 12. [

4, the step of picking up the fluorescent film pieces is a step of picking up the fluorescent film pieces 12 to be separated from the base film 17, that is, the step of picking up the film piece assembly 11 from the base film 17 17). The work of separating and picking up the film piece assembly 11 from the base film 17 can be done by the worker's human power but it is also possible to use a wedge-shaped die 40, a pickup collet up collet (30), as shown in FIG. Specifically, when the film piece assembly 11 is fed with the printed base film 17 passing along the outer circumferential surface of the wedge-shaped die 40, the base film 17 reaches the edge of the wedge- The film piece assembly 11 is separated from the base film 17 while the progress path is sharply bent. The film piece assembly 11 separated from the base film 17 is supported on the film piece supporting columns 44 in front of the edge 42 as the base film 17 proceeds. The pick-up collet 30 descends downward while being aligned with the film piece supporting posts 44 and sucks air at the lower end thereof to pick up and pick up the film piece assembly 11 supported by the film piece supporting columns 44. However, the method of using the pick-up collet 30 and the wedge-shaped die 40 is merely an example of the step of picking up the fluorescent film piece, and the present invention is not limited thereto.

5, in the step of mounting the fluorescent film pieces, the fluorescent film pieces 12 picked up before the sealing resin 10 injected into the LED mounting grooves of the lead frame 4 are completely cured is sealed with the sealing resin 10, In other words, placing the film piece assembly 11 on the upper side of the sealing resin 10 which is not fully cured.

As in the case of separating and picking up the film piece assembly 11 from the base film 17 (see Fig. 4), the operation of mounting the film piece assembly 11 on the upper side of the sealing resin 10 is performed by the worker's work force (Manpower), but may also be performed automatically through a film pick-up device equipped with a pick-up collet (30). Concretely, the pick-up collet 30 adsorbed by the film piece assembly 11 is moved to align with the upper side of the lead frame 4 into which the sealing resin 10 is injected, and the pick- 4) and stops suction of air through the lower end of the pick-up collet 30, the adsorption is released, and the film piece assembly 11 is released by gravity to the upper side of the sealing resin 10 . However, the method of using the pick-up collet 30 is merely an example of the step of mounting a fluorescent film piece, and is not limited thereto.

The curing step is a step of completely curing the sealing resin 10 after the step of mounting the fluorescent film piece to fix the fluorescent film piece 12 to the sealing resin 10, To the sealing resin (10). The lead frame 4 on which the film piece assembly 11 is mounted is left at room temperature or higher than room temperature so that the sealing resin 10 is cured and the film piece assembly 11 is fixed to the sealing resin 10 )do. The LED package 1 shown in Fig. 1 is completed through the curing step.

Meanwhile, the LED package manufacturing method described above is implemented by an automated LED package manufacturing apparatus in which a plurality of lead frames 4 are mounted on a carrier, the carriers are moved, and work is sequentially performed in each step In this case, mass production of the LED package is possible.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1: LED package 4: lead frame
7: LED 8: Bonding wire
10: sealing resin 11: film piece assembly
12: fluorescent film piece 13: protective film piece

Claims (10)

delete delete delete delete delete An LED mounting step of mounting an LED on a lead frame having an LED mounting groove with an opened upper surface and electrically connecting the LED to the lead frame;
A sealing resin injecting step of injecting and filling a liquid transparent sealing resin into the LED mounting groove;
A fluorescent film piece forming step of screen printing a phosphor ink onto a base film to form a piece of fluorescent film;
Picking up a piece of fluorescent film to be separated from the base film;
A step of mounting a fluorescent film on the upper side of the resin for encapsulation, before the encapsulating resin injected into the LED mounting groove is completely cured; And
And a curing step of completely curing the sealing resin to fix the fluorescent film piece to the sealing resin. The method according to claim 6,
The step of forming the fluorescent film piece may include forming a protective film piece that forms a protective film piece on the fluorescent film piece by screen printing the silicone resin on the fluorescent film piece formed on the base film and curing at a temperature higher than room temperature or room temperature The method comprising the steps of: The method according to claim 6,
Wherein the step of forming the fluorescent film piece comprises screen printing a transparent ultraviolet ray cured resin which is cured by infrared irradiation so as to overlap with the fluorescent film piece and irradiating infrared rays onto the UV cured resin to protect And a protective film piece forming step of forming a film piece. The method according to claim 6,
Wherein the thickness of the fluorescent film piece is 30 to 90 占 퐉. The method according to claim 6,
The fluorescent ink is formed by including 25 to 60% by weight of a binder resin mixture containing a polyester resin, an acrylic resin, a cellulose resin and a diluent, 30 to 70% by weight of a fluorescent filler, and 5 to 20% by weight of a solvent Wherein the LED package comprises a plurality of LED packages.

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