KR100826414B1 - Led package and surface mounting technology - Google Patents

Abstract

An LED package and a surface mounting method are provided to protect an LED from a shock in a surface mounting process by using a housing. An LED chip includes a first electrode and a second electrode. A package body includes a chip mounting region on which the LED chip is mounted. A first lead frame(33a) and a second lead frame(33b) are installed on the package body. The first electrode and the second electrode of the LED chip are connected to the first lead frame and the second lead frame, respectively. A housing(39) includes a cover formed on an upper surface of the LED chip, a vertical rib extended from a lateral part of the cover, and a coupling part formed at an end of the vertical rib. The coupling part of the housing is coupled with the package body.

Description

LED package and surface mount process {LED PACKAGE AND SURFACE MOUNTING TECHNOLOGY}

1 is for explaining a process of surface-mounting a conventional LED package on a substrate.

2 is a perspective view showing a housing mounted to a main body of an LED package according to an embodiment of the present invention.

3A and 3B are a perspective view and a side view showing an LED package according to an embodiment of the present invention.

4A to 4D are perspective views for explaining a surface mounting process according to one embodiment of another aspect of the present invention.

<Code Description of Main Parts of Drawing>

11: LED chip 12, 32, 42: package body

13a, 33a, 43a: first lead frame 13b, 33b, 43b: second lead frame

14,34,44: Lens 15: Transparent resin part

20,39, H: Housing 19,49: Pickup nozzle

21: housing cover 22, 37: vertical rib

F: Fastening part C: Mounting groove

47: substrate 48a: pad

48b: solder 48c: adhesive

The present invention relates to an LED package, and more particularly, to a LED package that can minimize the impact on the LED during the surface mounting process by employing a housing that protects the LED package and a process for surface-mounting the same.

As the electronics industry develops, various display devices having small size and low energy consumption are being developed, and optical devices such as video devices, computers, mobile communication terminals, and flashes are being developed using the same.

In general, a light emitting diode (LED) is a light emitting device that generates light by using a light emitting phenomenon (also called 'electric field emission') generated when a voltage is applied to a semiconductor. As the material of the LED, materials satisfying the conditions such that the light emission wavelength is present in the visible or near infrared region, the light emission efficiency is high, and the p-n junction can be manufactured are suitable. Such materials include gallium nitride (GaN), gallium arsenide (GaAs), gallium phosphide (GaP), gallium-arsenide-phosphorus (GaAs1-x Px), gallium-aluminum-arsenic (Ga1-xAlxAs), indium phosphide (InP) ), Compound semiconductors such as indium-gallium-phosphorus (In1-xGaxP) are used.

Such LEDs have advantages in that they are smaller in size, longer in lifespan, and have higher energy efficiency and lower operating voltage than conventional light sources. Therefore, an LED having such an advantage is used as a light source of the LCD backlight module.

The structure of such an LED package for an optical device generally consists of a body portion having a cavity in the center. After the LED chip is mounted in the cavity, the cavity is filled with a transparent resin such as an epoxy resin. In addition, a lens is formed on the upper portion of the LED chip can be a function to improve the light extraction efficiency by refracting the light generated from the LED chip to be emitted within a certain direction angle.

Meanwhile, in order to use the LED package as a backlight unit or a final light emitting device, a process of mounting the LED package on a substrate is required.

Referring to FIG. 1, FIG. 1 illustrates a surface mount technology (SMT) for surface mounting a conventional LED package on a substrate.

According to FIG. 1, a conventional LED package includes a transparent resin part filling an LED chip 11, a package body part 12, first and second lead frames 13a and 13b, a wire W, and a recess of the package body part. It comprises a 15 and the lens 14. The LED package is subjected to vacuum suction in the direction of the arrow to the pickup nozzle 19 for positioning on a substrate (not shown) during the surface mounting process. In this case, in general, the portion of the LED package adsorbed to the pickup nozzle 19 is the lens portion 14, and if there is no lens, the transparent resin portion 15. As such, the lens 14 or the transparent resin part 15 vacuum-absorbed to the pick-up nozzle 19 is very important in terms of determining the luminous efficiency of the light emitted from the LED chip 11. In this case, since the lens 14 or the transparent resin part 15 is generally composed of a gel-type resin (Resin) of plastic, glass or silicon series, respectively, the durability against impact is weak. In particular, when an impact is applied to the transparent resin part 15, there is a possibility that deformation may occur in the wire W enclosed therein, thereby adversely affecting the reliability of the LED package. In addition, when scratches occur due to the impact on the lens 14, there is a problem that the light extraction efficiency may be lowered.

Therefore, a method of protecting the lens or the transparent resin portion of the LED package is required during the surface mounting process.

The present invention is to solve the above problems of the prior art, the object of the LED package that can minimize the impact on the LED during the surface mounting process by adopting a housing for protecting the LED package and surface-mounted on the substrate To provide a process.

In order to achieve the above technical problem, an aspect of the present invention,

An LED chip having first and second electrodes, a package main body providing a mounting area of the LED chip, and a package main body mounted to the package main body and connected to the first and second electrodes of the LED chip, respectively. A LED having a first lead frame and a cover formed on the LED chip, a housing having a vertical rib formed downwardly extending from the side of the cover, and a binding part formed at the end of the vertical rib to be bonded to the package main body; Provide the package.

In this case, with respect to the binding means of the LED package and the housing, the mounting groove is formed on the side of the package body portion, it is preferable that the binding portion included in the housing is an elastic fastener bound with the mounting groove. Here, the vertical ribs are formed to extend from two opposite sides of the cover, and the mounting groove of the package body portion is adjacent to the surface on which the first and second lead frames are mounted among the side surfaces of the package body portion. It may be formed in.

On the other hand, the housing employed in the present invention is preferably removed after mounting the LED package on the substrate, the housing may be made of a material that is deformed at the reflow process temperature. To this end, the housing is preferably made of a plastic-based material.

Preferably, the lens may further include a lens formed between the LED chip and the cover of the housing. In this case, the housing is preferably mounted to the package body so that the cover and the lens are spaced apart from each other.

In addition, at least a portion of the region between the LED chip and the housing cover may be a transparent resin portion filled with transparent resin, in which case the housing is mounted on the package body to be spaced apart from each other. It is preferable.

Another aspect of the invention,

Providing an LED package of any one of the above-described LED packages, preparing a substrate for mounting the LED package, forming a pad in an area of the upper surface of the substrate on which the LED package is to be mounted, and Forming a solder on a pad, disposing the LED package on the substrate such that the first and second lead frames are respectively positioned on the solder, and melting the solder by a reflow process to Providing a surface mount process comprising securing a first and second lead frame onto the substrate and removing the housing from the LED package.

In this case, the step of disposing the LED package on the substrate, the vacuum suction of the cover of the housing of the LED package with a pick-up nozzle (Pick up nozzle) and the vacuum state after moving the pickup nozzle on the substrate It is preferable to include the step of releasing.

Preferably, the housing is made of a material deformed at the reflow process temperature, it may be deformed in the step of melting the solder. In this case, the step of removing the housing from the LED package is preferably performed by blowing the housing after the housing is deformed to separate the binding portion from the mounting groove of the LED package.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a perspective view showing a housing mounted to a main body of an LED package according to an embodiment of the present invention.

Referring to FIG. 2, the housing 20 according to the present embodiment is a cover 21 for protecting the LED package, and is not mounted to the LED package, and each of the two sides of the cover 21 facing each other. It comprises two vertical ribs 22 and the binding portion F extending downward. Here, the binding portion (F) to be bonded to the main body portion of the LED package is preferably a resilient fixture, so that the housing 20 is a structure that is easily removable from the LED package. In addition, in order to effectively protect the LED package, the size of the cover 21 is preferably larger than the lens or transparent resin portion of the general LED package.

On the other hand, since the housing 20 employed in the present embodiment should be removed after mounting the LED package on the substrate, it is preferable that the housing 20 is made of a material that can be deformed by heat at a reflow process temperature. As described below, the reflow process temperature may be about 200 to 300 ° C. That is, the binding portion F, which is deformed by heat, is preferably made of a material which can be separated from the mounting groove of the package body portion, and the housing 20 is made of a plastic-based material, specifically, PPA (Polyphethal Amide) Or the like.

3A and 3B are a perspective view and a side view, respectively, illustrating an LED package according to an embodiment of the present invention.

The LED package 30 according to the present embodiment includes an LED chip, a package main body 32, first and second lead frames 33a and 33b, a transparent resin filling a recess formed in the package main body, a lens 34, and It is a structure including a housing 39.

The LED chip has first and second electrodes (not shown), and the first and second electrodes are connected to the first and second lead frames 33a and 33b by wires, respectively. In addition, the first and second lead frames 33a and 33b extend outside the package body 32 in the longitudinal direction to form external terminals.

The package main body 32 is formed by molding a high reflectance resin, and first and second lead frames 33a and 33b are disposed, and recesses and walls around the LED chip are formed. It is. Although not shown in detail in FIG. 3A, the concave portion has a flat V-shape with a flat bottom and widening in the front, i.e., an upward direction. This is to guide the light emitted from the LED chip in the upward direction. However, the present invention is not limited thereto, and although not illustrated, the LED chip may be mounted in a planar mounting area provided by the package body instead of the recess.

In addition, the mounting groove (C) is formed on the side surface of the package body portion 32, it is a structure formed to bind to the package body portion 32 by a binding portion formed at the end of the vertical rib 37 of the housing. . In this case, as shown in FIG. 3A, the mounting groove C is formed on a surface adjacent to the surface on which the first and second lead frames 33a and 33b are mounted among the four side surfaces of the package main body 32. It is structurally preferred.

On the other hand, the inside of the recess is filled with a transparent resin to seal the LED chip from the outside. In this case, the transparent resin may contain a fluorescent material for converting blue light or ultraviolet light generated from the LED chip into white light.

In addition, the lens 34 is formed on the concave portion, and the light generated from the LED chip is refracted to be emitted within a certain direction angle to improve the light extraction efficiency. In general, the lens 34 has a hemispherical shape and may be made of a transparent material such as plastic or glass.

3B is a side view seen from the side of the first lead frame 33a, and shows a structure in which the cover of the housing 39 is spaced apart from the lens 34 by a predetermined distance. In the process of surface-mounting the LED package to the substrate, in particular during the reflow process, the housing 39 may be deformed by heat, so that the cover of the housing 39 is spaced apart from the lens 34 by a predetermined distance (t) from each other. It is preferable. In addition, although not shown, the lens 34 may not be employed in the present embodiment as an optional component. In this case, the housing may be packaged such that the transparent resin parts filling the cover and the recess are spaced from each other. It is preferable to be attached to a main-body part.

Hereinafter, a surface mounting process according to an embodiment of another aspect of the present invention will be described with reference to FIGS. 4A to 4D.

First, as shown in FIG. 4A, a pad 48a, an adhesive part 48c, and a solder 48b are formed on the pad in the area where the LED package on the substrate 47 is to be mounted, and then the LED is picked up using the pickup nozzle 49. The package P is disposed on the substrate 47.

In this case, although not shown, the process of forming the solder 48b may be performed by applying a creamed solder on the pad 48a and applying pressure with a squeegee or the like.

On the other hand, in the step of placing the LED package (P) on the substrate 47, by vacuum suction the cover portion of the housing (H) with the pickup nozzle 49 to mount the LED package (P) on the substrate 47 After moving to the area, it is executed by releasing the vacuum state and blowing the LED package P in the direction of the arrow as shown in Fig. 4A.

In this case, the vacuum suction part by the pickup nozzle 49 becomes a cover part of the housing H, so that the light exiting part of the lens 44 or the like may be prevented from being damaged by the shock during the vacuum suction process as in the prior art. Can be.

On the other hand, on the substrate 47 on which the LED package P is to be mounted, a pad 48a is disposed in a region where the first and second lead frames 43a and 43b of the LED package P are to be fixed. An adhesive portion 48c is formed at a portion where 42 is placed, and a solder 48b is formed at the pad 48a. Here, the LED package P may have a structure according to the embodiment described with reference to FIG. 3, and as described above, the housing H, the lens 44, the package main body 42, and the first and second leads. Frames 43a and 43b and the like. In addition, the housing (H) includes a binding portion that is attached to the cover, the vertical rib and the mounting groove (C) of the package body portion (42).

Subsequently, as shown in FIG. 4B, the substrate 47 and the LED package P are reflowed. As a result, the first and second lead frames 43a and 43b may be fixed on the substrate 47. That is, the substrate 47 and the LED package P are passed through a heating furnace having a high temperature atmosphere of about 200 to 300 ° C., and heat is applied to the upper and lower surfaces of the substrate 47 and the LED package P, and the solder (48b) is melted.

This reflow process deforms by heat as shown in FIG. 4C and the binding portion is separated from the mounting groove C of the package main body 42. This is because the housing H is made of a material that is easily deformed by heat such as PPA. In more detail, the process of separating the binding portion, the housing (H) is fixed by the binding portion at the side, when applied heat is recessed into the central portion of the cover of the housing (H), the binding portion is mounted It will fall out of the dragon groove (C). Even after the reflow process, even when the binding portion is still attached to the mounting groove C, the binding force between the binding portion and the mounting groove C is relatively weakened by the deformation of the housing H. Therefore, the housing H may be removed from the package main body 42 through a simple separation process such as blowing.

Next, the LED package mounted on the substrate 47 through the above process is shown in Figure 4d. As shown in FIG. 4D, the housing is removed from the LED package, and thus, there is little damage to the lens 44 or other parts of the package even during the surface mounting process. The deterioration of characteristics can be minimized.

It is intended that the invention not be limited by the foregoing embodiments and the accompanying drawings, but rather by the claims appended hereto. Accordingly, various forms of substitution, modification, and alteration may be made by those skilled in the art without departing from the technical spirit of the present invention described in the claims, which are also within the scope of the present invention. something to do.

As described above, according to the present invention, by employing a housing protecting the LED package, it is possible to obtain an LED package capable of minimizing the impact on the LED during the surface mounting process and a surface mounting process on the substrate.

Claims (13)

An LED chip having first and second electrodes; A package body part providing a mounting area of the LED chip; First and second lead frames mounted on the package main body and connected to first and second electrodes of the LED chip; And A cover formed on the LED chip, a vertical rib extending downward from the side of the cover, and a binding part formed to be bonded to the package main body at an end of the vertical rib, the material being deformed at a reflow process temperature housing; LED package comprising a. The method of claim 1, The mounting groove is formed on the side of the package body, The binding part included in the housing is an LED package, characterized in that the resilient fasteners and the mounting groove. The method of claim 2, The vertical ribs are formed extending from two opposite sides of the cover, The mounting groove of the package main body is formed on the side of the package body portion adjacent to the surface on which the first and second lead frame is mounted, LED package. delete The method of claim 1, LED housing, characterized in that made of a plastic-based material. The method of claim 1, And a lens formed between the LED chip and the cover of the housing. The method of claim 6, The housing is an LED package, characterized in that mounted on the package body to the cover and the lens spaced apart from each other. The method of claim 1, At least a portion of the region between the LED chip and the housing cover is a LED package, characterized in that the transparent resin portion filled with a transparent resin. The method of claim 8, The housing is an LED package, characterized in that mounted on the package body portion such that the cover and the transparent resin portion spaced apart from each other. Providing an LED package according to any one of claims 1 to 3 and 5 to 9; Preparing a substrate for mounting the LED package; Forming a pad on an upper surface of the substrate on which the LED package is to be mounted; Forming solder on the pad; Placing the LED package on the substrate such that the first and second lead frames are respectively positioned on the solder; Melting the solder by a reflow process to fix the first and second lead frames onto the substrate; And Removing a housing from the LED package; Surface mounting process comprising a. The method of claim 10, The disposing of the LED package on the substrate includes vacuum suctioning a cover of the housing of the LED package with a pickup nozzle and releasing the vacuum after moving the pickup nozzle onto the substrate. Surface mounting process characterized by the above-mentioned. The method of claim 10, And the housing is made of a material that is deformed at a reflow process temperature and is deformed in melting the solder. The method of claim 12, Removing the housing from the LED package, And after the housing is deformed, by blowing the housing to separate the binding portion from the mounting groove of the LED package.

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