KR20100077865A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to prevent the slip of a lead frame by forming a hole on the contact surface between a printed circuit board and the lead frame. CONSTITUTION: A light emitting device comprises a light emitting chip(110), a lead frame(130,140) and a package body(120). The lead frame is electrically connected to the light emitting chip. The lead frame includes a mounting surface, a contact surface, and a hole. The mounting surface is electrically connected to the light emitting chip. The contact surface is electrically connected to the mounting surface. The hole is formed on the contact surface. The package body includes a housing and a reflector. The housing supports the light emitting chip and the lead frame. The reflector reflects the light emitted from the light emitting chip.

Description

Light emitting device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly, to a light emitting device capable of improving adhesion to a printed circuit board (PCB).

Generally, a light emitting device includes a light emitting chip, a housing for supporting the light emitting chip, and first and second lead frames formed on the housing and electrically connected to the light emitting chip.

Various light emitting chips are used for such a light emitting device. For example, a light emitting diode using light emitting diodes is formed by using a pn junction structure of a semiconductor to form a minority carrier (electron or hole) injected and emitting light by recombination thereof. Diode; LED) is used. Light emitting diodes include red light emitting diodes using GaAsP and the like, green light emitting diodes using GaP and the like, and blue light emitting diodes using an InGaN / AlGaN double hetero structure.

In addition, the light emitting device is manufactured in various shapes depending on the type of chip, the shape of the package, or the light emitting direction. For example, chip type, lamp type, top view type, and side view type are manufactured. Recently, due to slimming and low power of liquid crystal display (LCD) products, There is an increasing demand for side view type light emitting devices used as a backlight unit light source of LCDs.

In the light emitting device, the first and second lead frames are mounted on separate printed circuit boards so that external power is applied to the light emitting chip. That is, after a predetermined amount of solder cream is doped in one region of the printed circuit board, the first and second lead frames are brought into contact with the solder cream to mount the light emitting device.

However, the solder cream has fluidity, and the lead frame in contact with the solder cream has a smooth surface. As a result, the lead frame slips from the solder cream during reflow, and thus the adhesive force with the printed circuit board is lowered. Accordingly, the light emitting device may be distorted or short-circuited on the printed circuit board.

The present invention provides a light emitting device capable of improving adhesion to a printed circuit board.

The present invention provides a light emitting device that deforms the shape of a lead frame to form a hole in one region of the lead frame mounted on a printed circuit board.

The present invention provides a light emitting device in which solder cream is introduced into a hole formed in one region of a lead frame mounted on a printed circuit board and cured so that the solder cream fixes the lead frame through the hole.

A light emitting device according to an aspect of the present invention includes a light emitting chip; A lead frame electrically connected to the light emitting chip; And a package body supporting the light emitting chip and the lead frame, wherein the lead frame includes a mounting surface on which the light emitting chip is electrically connected, and a contact surface formed outside the package body and electrically connected to the mounting surface. And a hole formed in the contact surface.

The package body may include a housing supporting the light emitting chip and the lead frame; And a reflector formed on the housing and forming an opening through which light generated by the light emitting chip is emitted.

The reflector includes at least a pair of reflective surfaces protruding on the housing.

The molding apparatus may further include a molding part molded into the reflector to encapsulate the light emitting chip.

The contact surface is bent from the mounting surface, and further includes at least one side bent from the contact surface, or further includes at least one side bent downward from the mounting surface.

The contact surface is in contact with a solder pattern of a printed circuit board, and the solder pattern flows into the hole.

According to the present invention, at least a part of the lead frame is bent downward in a direction perpendicular to the upper surface of the housing to form a contact surface in contact with the printed circuit board, and to form a hole in a predetermined region of the contact surface. Then, the hole is positioned on the solder pattern of the printed circuit board so that a part of the solder pattern reaches the other surface of the contact surface through the hole and then hardens.

Therefore, a hole is formed in the contact surface with the printed circuit board to prevent the lead frame from slipping, and the one side and the other surface of the contact surface are fixed to the printed circuit board by the hole to improve the adhesion between the printed circuit board and the light emitting device. As a result, it is possible to prevent the light emitting device from falling off and twisting.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art the scope of the invention. It is provided for complete information. Like reference numerals in the drawings refer to like elements.

1 is a perspective view of a light emitting device according to an exemplary embodiment of the present invention, FIG. 2 is a diagram illustrating a lead frame of FIG. 1, FIG. 3 is a cross-sectional view of FIG. 1, and FIG. 4 is a plan view of a leaf frame before bending. to be.

1, 2, 3, and 4, a light emitting device according to an embodiment of the present invention includes a light emitting chip 110 generating light of a predetermined wavelength and a light emitting chip 110 on which a light emitting chip 110 is seated. A package body 120 having an opening through which light generated at 110 is emitted, and first and second lead frames 130 electrically connected to the light emitting chip 110 and mounted on a printed circuit board (not shown). 140).

The light emitting chip 110 has a stacked structure of a compound semiconductor having a P-N junction structure, and uses a phenomenon in which light is emitted by recombination of minority carriers (electrons or holes). The light emitting chip 110 may include an active layer formed between the first and second semiconductor layers and the first and second semiconductor layers, and the first and second semiconductor layers may be an N-type semiconductor layer and a P-type semiconductor layer, respectively. have. In addition, an N-type electrode and a P-type electrode electrically connected to the N-type semiconductor layer and the P-type semiconductor layer, respectively, are formed, and the N-type electrode and the P-type electrode of the light emitting chip 110 may include the first and second lead frames ( 130 and 140, respectively. In this case, the N-type electrode and the P-type electrode may be formed on the same plane, respectively, may be formed on different planes.

The package body 120 supports the first and second lead frames 130 and 140 exposed to one side and the other side, and the housing 121 on which the light emitting chip 110 is seated, and formed on the housing 121 and emitting light. And a reflector 123 forming an opening through which the light generated by the chip 110 is emitted. The package body 120 may be manufactured by a transfer molding method using an epoxy mold compound (EMC) in which a white pigment is added to a thermosetting resin, for example, an epoxy resin. Therefore, the housing 121 and the reflector 123 may be integrally manufactured.

The reflector 123 includes at least two reflective surfaces protruding upward from the top surface of the housing 121. For example, two reflective surfaces may protrude from the two surfaces in the Y direction parallel to each other in the Z direction, and four reflective surfaces may protrude from the four surfaces in the X and Y directions parallel to each other in the Z direction. . In this case, the heights of the two reflective surfaces parallel to the X direction may be adjusted. In this case, the emission range of the light generated from the light emitting chip 110 may be adjusted. In addition, the reflective surface may be formed to be inclined at an angle. Of course, the shape of the reflector 123 is not limited thereto and may be variously changed to adjust the emission range of the light emitted from the light emitting chip 110 according to the use of the light emitting device.

The housing 121 and the reflector 123 may be manufactured in various shapes according to the use of the light emitting device. For example, as shown, it may be formed in a rectangular shape having a first length in the X direction and a second length longer than the first length in the Y direction. In addition, the housing 121 and the reflector 123 may be manufactured in the same size in the X direction and the Y direction, but as shown in FIG. 1, the reflector 123 may be manufactured larger than the housing 121 in the Y direction. have. For example, the width of the reflector 123 in the Y direction may be manufactured by adding the width of the housing 121 to the widths of the second surfaces 133 and 143 of the first and second lead frames 130 and 140. Can be.

The package body 120 is formed with a molding part 160 formed in an opening formed in the reflector 123 to seal the light emitting chip 110 and a part of the first and second lead frames 130 and 140. The molding part 160 may be formed of, for example, a silicone resin or an epoxy resin that is thermosetting and light transmissive. In this case, the molding part 160 is preferably formed by a transfer molding method when the reflecting surfaces of the reflector 123 protrude on both sides, and when the reflecting surfaces of the reflector 123 protrude on the four sides, transfer It can be formed by a molding method or a dotting molding method. However, the present invention is not limited thereto, and any material may be used as long as the resin is transparent enough to transmit light according to the use of the light emitting device, and various molding techniques may be used to mold each material. In addition, the molding unit 160 may further include a diffusion agent (not shown) for uniformly emitting light by diffusing light emitted from the light emitting chip 110 by scattering. As the diffusion agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide, or the like may be used. In addition, the molding unit 160 may further include a phosphor (not shown). The phosphor emits light having a wavelength different from that absorbed by absorbing a portion of the light generated from the light emitting chip 110, and is composed of active ions in which impurities are mixed at an appropriate position of the host crystal. The role of the active ions determines the emission color by determining the energy level involved in the emission process, and the emission color is determined by the energy gap between the ground state and the excited state of the active ions in the crystal structure.

The first and second lead frames 130 and 140 are supported on the housing 121 and spaced apart from each other between the housing 121 and the reflector 123. The light emitting chip 110 may be mounted on the first and second lead frames 130 and 140. The light emitting chip 110 may be mounted on the first lead frame 130, and the light emitting chip 110 may be connected to the wire 150. It may be electrically connected to the second lead frame 140 through. In addition, the light emitting chip 110 may be mounted on the housing 121 and electrically connected to the first and second lead frames 130 and 140 through the wire 150. As the light emitting chip 110 and the first and second lead frames 130 and 140 are electrically connected to each other, power from the outside is applied to the light emitting chip 110. The first and second lead frames 130 and 140 may have a mounting surface electrically connected to the light emitting chip 110 and a contact surface bent downward from a predetermined region of the mounting surface to be electrically connected to a printed circuit board (not shown). It includes. Specifically, as shown in FIG. 4, the first and second lead frames 130 and 140 are provided on the upper surface of the housing 121 and are arranged in parallel with the upper surface of the housing 121, that is, in the Y direction. The surfaces 131 and 141, the second surfaces 133 and 143 that are bent downward from at least a portion of one side of the first surfaces 131 and 141, and the second surfaces 133 and 143 that are bent from the housing ( A third face 135 and 145 parallel to the minor plane of 121 and a fourth face 137 and 147 bent from the third face 135 and 145 and parallel to the second face 133 and 143. do. Thus, a predetermined gap is provided between the housing 121 and the second surfaces 133 and 143, the third surfaces 135 and 145, and the fourth surfaces 137 and 147 of the first and second lead frames 130 and 140. Space is provided. Here, the first surfaces 131 and 141 are mounting surfaces to which the light emitting chip 110 is directly mounted or connected through a wire 150, and the second surfaces 133 and 143 are electrically connected to the printed circuit board. It becomes cotton. The contact face may be the fourth face 137 and 147 depending on the electrical connection with the printed circuit board. In addition, holes 139 and 149 are provided in a predetermined region, preferably a central region, of the contact surface, that is, the second surfaces 133 and 143. The holes 139 and 149 may be provided in the fourth surfaces 137 and 147 according to the electrical connection state of the printed circuit board, and are simultaneously provided in the second surfaces 133 and 143 and the fourth surfaces 137 and 147. Can be. The holes 139 and 149 are introduced into the other side of the second side 133 and 143 through the holes 139 and 149 when they are in electrical contact with the printed circuit board using, for example, solder cream. When the cream is cured, one side and the other side of the second side 133 and 143 are soldered through the holes 139 and 149 to serve to fix the light emitting device.

In the light emitting device according to the exemplary embodiment, the first and second lead frames 130 and 140 may be connected to the light emitting chip 110 as well as the first surface 131 and 141. 131 and 141 and a second surface 133 and 143, a third surface 135 and 145 and a fourth surface 137 and 147, which are formed in a vertical direction downward, are formed to form a contact surface with the printed circuit board. The holes 139 and 149 are formed on the two surfaces 133 and 143. However, the first and second lead frames 130 and 140 may have a first surface 131 and 141 electrically connected to the light emitting chip 110, and a second surface 133 in contact with the printed circuit board and having holes formed therein. And 143) can be manufactured in any shape.

For example, as illustrated in FIGS. 5, 6, and 7, the first lead frames 130 and 140 may include the first surfaces 131 and 141 and the second surfaces 133 and 143 having holes 139 and 149. ) May be included only.

In addition, as shown in FIG. 8, the second surfaces 133 and 143, the third surfaces 135 and 145, and the fourth surfaces 137 and 147 of the first and second lead frames 130 and 140 may be formed. It may be formed by bending downward from the three surfaces of the first surface (131 and 141), respectively.

9 is a side view illustrating a state in which a light emitting device according to an embodiment of the present invention is mounted on a printed circuit board.

As shown in FIG. 9, in the light emitting device according to the present invention, the second surfaces 133 and 135 of the first and second lead frames 130 and 140 may have solder patterns 210 on the printed circuit board 200, for example. For example, it is mounted on solder cream. That is, when the holes 139 and 149 of the second surfaces 133 and 135 are positioned on the solder pattern 210, a part of the solder pattern 210 may pass through the holes 139 and 149 and the second surfaces 133 and 149. 143) flows into the other side. In addition, when the solder pattern 210, for example, solder cream is cured, the solder pattern 210 fixes one surface and the other surface of the second surfaces 133 and 143 through the holes 139 and 149. Thus, the light emitting device can be firmly adhered to the printed circuit board 210.

Although described above with reference to the drawings and embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit of the invention described in the claims below. I can understand.

1 is a perspective view of a light emitting device according to an embodiment of the present invention;

2 is a perspective view of a lead frame used in a light emitting device according to an embodiment of the present invention.

3 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.

4 is a plan view before bending of the lead frame used in the light emitting device according to an embodiment of the present invention.

5 is a perspective view of a light emitting device according to another embodiment of the present invention.

6 is a perspective view of a lead frame used in a light emitting device according to another embodiment of the present invention.

7 is a plan view before bending of the lead frame used in the light emitting device according to another embodiment of the present invention.

8 is a plan view before bending of the lead frame according to another embodiment of the present invention.

9 is a schematic cross-sectional view for explaining a contact state with a printed circuit board of the light emitting device according to the present invention.

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

110: light emitting chip 120: package body

130: first lead frame 140: second lead frame

150: wire 160: molding part

Claims (8)

A light emitting chip; A lead frame electrically connected to the light emitting chip; And A package body supporting the light emitting chip and the lead frame; The lead frame includes a mounting surface to which the light emitting chip is electrically connected, a contact surface formed outside the package body to be electrically connected to the mounting surface, and a hole formed in the contact surface. The method of claim 1, wherein the package body comprises a housing for supporting the light emitting chip and the lead frame; And And a reflector formed on the housing and forming an opening through which light generated by the light emitting chip is emitted. The light emitting device of claim 2, wherein the reflector includes at least one pair of reflective surfaces protruding from the housing. 4. The light emitting device of claim 3, further comprising a molding part molded inside the reflector to encapsulate the light emitting chip. The light emitting device of claim 1, wherein the contact surface is bent from the mounting surface. The light emitting device of claim 5, further comprising at least one side surface bent from the contact surface. The light emitting device of claim 5, further comprising at least one side surface bent downward from the mounting surface. The light emitting device of claim 1, wherein the contact surface is in contact with a solder pattern of a printed circuit board, and the solder pattern is introduced into the hole.

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