KR20060007515A - Surface mount type light emitting device and package structure and method of manufacturing thereof - Google Patents

Abstract

The present invention relates to a surface-mounted light emitting device, a package structure and a manufacturing method thereof, wherein the package structure includes a chip seat portion protruding at a predetermined height from the base portion in a central portion of the base portion, The bottom surface of the heat dissipation main board and the chip mounting portion are exposed to the heat dissipation main board so as to surround the heat dissipation main board from the side of the base part to the top surface to enable surface mounting. And an auxiliary circuit board having at least one chip bonding pad electrically connected to the electrode pads on the upper surface thereof, and an auxiliary circuit board capable of focusing a beam diffused from the light emitting device chip to be seated on the chip seating part. It has a reflector formed above. According to the surface mount light emitting device, the package structure, and the manufacturing method thereof, both the flip type light emitting diode chip and the top-epit type light emitting diode chip can be mounted, and the light emitting diode chip can be mounted on a large heat dissipation main board. It is structured to focus light while being able to provide the advantage of improving luminous efficiency and heat dissipation ability.

Description

Surface mount light emitting device and package structure and method of manufacturing

1 is a perspective view showing a surface mounted light emitting diode according to an embodiment of the present invention;

2 is a cross-sectional view of FIG. 1,

FIG. 3 is a cross-sectional view illustrating a flip-type light emitting diode chip mounted on the package structure of FIG. 1.

4 is a cross-sectional view illustrating a state in which the light emitting device of FIG. 1 is mounted on an external circuit board.

FIG. 5 is an exploded perspective view illustrating some parts separated to explain a process of manufacturing the package structure of FIG. 1;

FIG. 6 is a rear view of the auxiliary circuit board of FIG. 5;

FIG. 7 is an exploded cross-sectional view illustrating a bonding process between the auxiliary circuit board, the heat dissipation main board, and the reflector of FIG. 5.

<Description of Symbols for Major Parts of Drawings>

100: light emitting diode 210: heat dissipation main board

230: auxiliary circuit board 250: electrode pad

270 reflector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mounted light emitting device, a package structure thereof, and a manufacturing method thereof, and more particularly, to a surface mounted light emitting device having a heat dissipation and light focusing structure suitable for high output, a package structure thereof, and a manufacturing method thereof.

Recently, as the light emitting diode (LED) is known to have a structure that emits white light by applying a phosphor, its application range has been extended to a lighting field that can replace a conventional light lamp in addition to a simple light emitting display function. . In addition, research on high power light emitting diodes suitable for lighting has been continuously conducted.

The light emitting diode, which is one of the semiconductor devices, decreases its lifespan and decreases the luminous efficiency when the temperature rises above the rated operating temperature. Therefore, in order to increase the output of the light emitting diodes, the light emitting diodes effectively emit heat generated from the light emitting diodes. Heat dissipation structure is required.

However, the conventional light emitting diode has a structure in which a lead frame on which a light emitting diode chip is mounted is molded with a plastic material. The light emitting diode of such a structure is difficult to be applied to a high output light emitting diode because the heat dissipation is low because the heat radiation is carried out through the lead frame. In addition, when the ultraviolet light emitting diode chip is applied, the plastic material applied as the molding material is easily deteriorated by the ultraviolet light emitted from the ultraviolet light emitting diode chip, thereby degrading durability.

The present applicant has applied for a light emitting device package structure having a large heat dissipation plate through Korean Patent Application No. 2003-0030478 and Korean Patent Application No. 2004-0012008 to improve such a problem.

In addition, the present applicant has been steadily developing a light emitting device capable of surface mounting while increasing the luminous efficiency and heat dissipation efficiency, and easy to manufacture.

The present invention has been made through such a development process to provide a surface-mounted light emitting device, a package structure and a manufacturing method thereof, which are easy to mount a light emitting device while improving heat dissipation ability and light emitting efficiency.

In order to achieve the above object, the surface mount light emitting device package structure according to the present invention has a base portion and a chip seat portion protruding at a predetermined height from the base portion in the center portion of the base portion, and for heat dissipation made of a heat dissipating material. A main substrate; It is bonded to the heat dissipation main board to surround the heat dissipation main board from the side of the base portion to the top surface so that the surface mounting is possible to expose the bottom surface of the heat dissipation main board and the chip seat. An auxiliary circuit board on which at least one electrode pad is formed, and at least one chip bonding pad electrically connected to the electrode pad at an upper surface thereof; And a reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip to be mounted on the chip seat.

Preferably, the upper surface of the auxiliary circuit board is formed to be parallel to the upper surface of the chip seat.

In addition, the reflector has at least an inner surface formed of at least one of silver, nickel, and aluminum.

In addition, in order to achieve the above object, the surface-mounted light emitting device according to the present invention has a base portion and a chip seat portion protruding at a predetermined height from the base portion in the center portion of the base portion, and for heat dissipation made of a heat dissipating material A main substrate; It is bonded to the heat dissipation main board to surround the heat dissipation main board from the side of the base portion to the top surface so that the surface mounting is possible to expose the bottom surface of the heat dissipation main board and the chip seat. An auxiliary circuit board on which at least one electrode pad is formed, and at least one chip bonding pad electrically connected to the electrode pad at an upper surface thereof; At least one light emitting device chip mounted on the chip seat; A reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip mounted on the chip seat to the periphery; And a cap coupled to shield an internal space between the reflector and the light emitting diode chip.

The cap is preferably applied to the focusing lens bonded to the reflector.

In addition, the manufacturing method of the surface-mounted light emitting device according to the present invention to achieve the above object is a. Forming a heat dissipation main substrate having a base portion and a chip seat portion protruding from the base portion at a predetermined height in a central portion of the base portion and made of a heat dissipation material; I. An insertion hole formed to enclose the heat dissipation main substrate from the side of the base portion to the top surface of the heat dissipation main substrate to expose the bottom of the heat dissipation main substrate and the chip mounting portion, and at least one electrode pad on the bottom thereof; And forming an auxiliary circuit board having at least one chip bonding pad electrically connected to the electrode pad on an upper surface thereof. All. Bonding the auxiliary circuit board and the heat dissipation main board to the heat dissipation main board in the insertion hole; hemp. And bonding a reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip to be mounted on the chip seat.

Hereinafter, a light emitting device, a package structure thereof, and a manufacturing method thereof according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing a light emitting diode according to an embodiment of the present invention, Figure 2 is a cross-sectional view of FIG.

1 and 2, the light emitting diode 100 includes a light emitting diode chip 110, a lens 120, and a package structure 200.

The package structure 200 includes a heat dissipation main substrate 210, an auxiliary circuit board 230, and a reflector 270.

The heat dissipation main substrate 210 has a structure having a base portion 211 and a light emitting diode chip mounting chip mounting portion 212 formed to protrude at a predetermined height in the center portion of the base portion 211.

In the illustrated example, the base portion 211 of the heat dissipation main substrate 210 may be formed in a circular shape and may be formed in various shapes such as a square.

In addition, the chip seat 212 may also be formed in various forms such as a circle in addition to the square.

The heat dissipation main substrate 210 is formed of a heat dissipation material having good thermal conductivity, for example, a metal material or a ceramic material.

As a material of the heat dissipation main substrate 210, copper or a copper alloy such as brass, tungsten / copper, molybdenum / copper alloy, AlN, SiC, or the like may be applied.

Preferably, the heat dissipation main substrate 210 is formed in the structure shown in the above-described heat dissipation material and then plated with a nickel material. More preferably, the heat dissipation main substrate 210 is second plated with silver or gold on the nickel plating layer.

At least one light emitting diode chip 110 is mounted on the chip seat 212 of the heat dissipation main substrate 210. Unlike the illustrated example, the light emitting diode chip 110 may be mounted on the chip seat 212 through a submount (not shown).

The auxiliary circuit board 230 is formed in a structure surrounding the top and side surfaces of the base portion 211 of the heat dissipation main substrate 210 to enable surface mounting, thereby providing a chip seat 212 of the heat dissipation main substrate 210. The bottom surface of the base portion 211 is coupled to the base portion 211 of the heat dissipation main substrate 210 to be exposed.

Four electrode pads 250 are formed on the bottom of the auxiliary circuit board 230 to electrically connect the LED chip 110 to the outside.

Four chip bonding pads 238 are formed on an upper surface of the auxiliary circuit board 230.

The chip bonding pad 238 is electrically connected to the electrode pad 250 formed to be exposed to the bottom portion of the auxiliary circuit board 230 so as to be electrically energized. Reference numeral 260 is a portion exposed to the outside of the conductive pattern for electrically connecting the electrode pad 250 and the chip bonding pad 238 to be electrically energized.

The chip bonding pad 238 is electrically coupled to the light emitting diode chip 110 by a gold wire 140.

Unlike the illustrated example, when the light emitting diode chip 110 is a flip type light emitting diode chip, as illustrated in FIG. 3, the chip bonding pad 238 may be electrically coupled to an electrode of the flip type light emitting diode chip 110 by soldering. Can be. Reference numeral 115 denotes a solder for coupling the flip type light emitting diode chip 110 to the heat dissipation main substrate 210.

In the auxiliary circuit board 230 having the above structure, the four chip bonding pads 238 are independently connected to the corresponding electrode pads 250. In the illustrated example, one LED chip 110 is connected to the chip seat. Although illustrated in FIG. 212, three light emitting diode chips may be mounted on the chip seat 212 to independently drive each other.

As an example, three light emitting diode chips (not shown), which emit red, green, and blue light, respectively, are mounted on the chip seat 212 to generate white light, and one of the four chip bonding pads 238 is common. The remaining three for the electrode may be connected to the corresponding electrode for driving the LED chip. Of course, the number of electrode pads 250 and the number of chip bonding pads 238 may be applied to at least four.

The auxiliary circuit board 230 is formed in a structure having an insertion hole (see FIG. 5; 239a and 239b) into which the base portion 211 and the chip seating portion 212 may be inserted, and bonded to the main substrate 210 for heat dissipation. It is desirable to.

In addition, the upper surface of the auxiliary circuit board 230 is preferably formed to be parallel to the horizontal surface so as to have the same height as the upper surface of the chip seat 212.

According to the package structure 200, the flip-type or top-emitting LED chip 110 may be mounted.

In addition, the bottom surface of the auxiliary circuit board 230 may be mounted with a solder or heat dissipation main board 210 to extend on the same line as the bottom surface of the heat dissipation main board 210 or to be bonded to the electrode pad 250 to enable surface mounting. In the case where the target external circuit board is bonded using an adhesive having good thermal conductivity, it may be formed to be slightly higher or lower than the bottom of the heat dissipation main board 210 in consideration of this. That is, as shown in FIG. 4, in order to increase the heat radiation efficiency of the heat dissipation main board 210, the heat dissipation main board 210 is soldered to the external circuit board 310 on which the light emitting device 100 is mounted. Solder to be applied so that the electrode pad 250 can be stably connected to the external circuit board 310 to be mounted by the solder 320 when it is in close contact with the adhesive 330 having good thermal conductivity. In consideration of the thickness range of 320 and the thickness range of the adhesive 330, the relative height of the bottom surface of the auxiliary circuit board 230 with respect to the bottom surface of the heat dissipation main substrate 210 may be appropriately determined. Typically, the thickness of the adhesive 330 is preferably lower than the thickness of the solder 320.

Unlike this, when the bottom surface of the heat dissipation main board 210 is spaced a predetermined distance from the external circuit board 310 to be mounted, the bottom surface of the auxiliary circuit board 230 with respect to the bottom of the heat dissipation main board 210 is taken into consideration. This is done by appropriately determining the relative height.

The auxiliary circuit board 230 may be implemented by a PCB substrate in which the chip bonding pad 238 and the electrode pad 250 are internally connected to each other.

Preferably, the auxiliary circuit board 230 is formed such that the chip bonding pad 238 and the electrode pad 250 are internally interconnected using at least one ceramic sheet made of alumina (Al ₂ O ₃ ). .

A preferred embodiment of such an auxiliary circuit board 230 will be described with reference to FIGS. 5 to 7.

The auxiliary circuit board 230 has a structure in which the first ceramic layer 231 to the fourth ceramic layer 234 are sequentially stacked.

Four electrode pads 250 are formed on the bottom surface of the first ceramic layer 231, and two electrode pads 250 are connected to each of the electrode pads 250 on the side adjacent to the corner portion and extend vertically along the side. The conductive pattern 260a is formed.

The electrode pad 250 is preferably formed on the bottom of the first ceramic layer 231 by tungsten (W) or molybdenum / manganese (Mo / Mn) alloy, and secondly, plated with nickel thereon. .

A second conductive pattern 260b extending vertically to be extended with the corresponding first conductive pattern 260a is formed at a side surface adjacent to the corner portion of the second ceramic layer 232.

Third and fourth conductive patterns 260c and 260d connected to each other are formed on side surfaces and upper surfaces adjacent to corner portions of the third ceramic layer 233.

A chip bonding pad 238 is formed on the top surface of the fourth ceramic layer 234. The chip bonding pad 238 is first formed of a material made of tungsten (W) or molybdenum / manganese (Mo / Mn) alloy, and then plated with nickel secondly, and finally with gold or silver thirdly. It is preferable to form.

In addition, a fifth conductive pattern 260e is formed in the fourth ceramic layer 234 by filling each of the chip bonding pads 238 with a conductive material through a through hole so as to be connected to the fourth conductive pattern 260d. .

The conductive pattern 260 is preferably formed of tungsten (W) or molybdenum / manganese (Mo / Mn) alloy.

The first insertion hole 239b formed at the center of the first ceramic layer 231 and the second ceramic layer 232 is formed in a shape and a size into which the base portion 211 can be inserted.

The second insertion hole 239a formed at the center of the third ceramic layer 233 and the fourth ceramic layer 234 is formed in a shape and a size into which the chip seat 212 may be inserted.

On the other hand, reference numeral 244 is an auxiliary pad for bonding formed on the bottom surface of the third ceramic layer 233, it is formed to provide ease of bonding with the heat dissipation main substrate 210.

Preferably, an auxiliary pad 245 for bonding is formed on an upper surface of the fourth ceramic layer 234 to be spaced apart from the chip bonding pad 238 in a region corresponding to the portion where the reflector 270 is to be bonded.

The auxiliary pads 244 and 245 may be formed by first forming a tungsten (W) or a molybdenum / manganese (Mo / Mn) alloy and then plating the second with nickel on the second pad.

The conductive pattern forming method for internally connecting the chip bonding pad 238 and the electrode pad 250 to each other may be applied differently from the illustrated example.

On the other hand, the corner portion 249 rounded to the inside of each corner of the auxiliary circuit board 230 in the case of manufacturing a plurality of auxiliary circuit board 230 or package structure 200 in a batch, each auxiliary circuit To provide ease of cutting of the substrate 230.

The reflector 270 is formed to focus light emitted from the light emitting diode chip 110.

That is, the reflector 270 is formed with a hole in the center, the inner surface is formed to have a curvature that the inner diameter becomes smaller as it proceeds downward from the upper surface to focus the light emitted from the light emitting diode chip 110.

The reflector 270 forms at least an inner surface of a material having high reflectance. For example, the inner surface of the reflector 270 is formed of at least one of silver, nickel, and aluminum.

That is, the reflector 270 is formed by molding any one of silver, nickel or aluminum as an example. Alternatively, the reflector 270 is formed by first forming a synthetic resin material or a metal material and then coating at least the inner surface of the inner surface with a material having a high reflectance. Here, as a coating material having a high reflectance, at least one of a reflective material group including silver, aluminum, and bright nickel is preferably applied.

Glossy nickel material here means the thing which added the gloss material to nickel. Examples of the material for the gloss include saccharin, formalin or those in which nickel sulfate, nickel chloride and boric acid are added.

The lens 120 is applied as an example of a cap for sealing and protecting the light emitting diode chip 110 and is bonded to the reflector 270. The junction between the lens 120 and the reflector 270 is sealed by a sealing material so that the inner space is sealed.

Alternatively, the cap may be formed by molding the inner space of the reflector with a transparent material such as silicon or epoxy instead of the lens 120.

In the light emitting diode 100 having the above structure, the light emitted from the light emitting diode chip 110 mounted on the heat dissipation main substrate 210 is focused by the reflector 270 and the lens 120 to emit a light beam at a desired divergence angle. Can be provided.

The curvature and shape of the lens 120 may be appropriately designed according to the divergence angle of light to be applied in addition to the illustrated structure.

The material of the lens 120 may be a transparent synthetic resin material or glass material.

In addition, the space formed between the lens 120 and the package structure 200 may be filled with a material similar to the refractive index of the lens 120 to be applied. As an example, a space formed between the lens 120 and the package structure 200 may be filled with a silicon material. In this case, it is possible to increase the light utilization efficiency by suppressing the rate at which light emitted from the light emitting diode chip 110 is reflected from the inner surface of the lens 120.

Although not shown, when the ultraviolet light emitting diode chip is applied, the planar lens may be bonded to the reflector 270 to be used.

The planar lens may be applied to the upper and lower surfaces of the base plate made of a transparent material without antireflection coding. In addition, when the ultraviolet light emitting diode chip is applied, the reflector 270 is preferably formed of an aluminum material having a high reflectance in the ultraviolet region.

Hereinafter, a manufacturing process of the light emitting diode having such a structure will be described.

First, the auxiliary circuit board 230, the heat dissipation main circuit board 210, and the reflector 270 are respectively formed.

The auxiliary circuit board 230 is formed to have the structure described above. That is, first, insertion holes 239a and 239b, first to third conductive patterns, and fifth conductive patterns 260a are formed in the ceramic sheets for forming the first ceramic layer 231 to the fourth ceramic layer 234, respectively. (260b) 260c and 260e formation side grooves and a conductive hole are formed. Next, a fifth conductive pattern 260e is formed by filling a metal paste into a conductive hole formed in a ceramic sheet, and a fourth conductive pattern 260d, a chip bonding pad 238, and an electrode pad are formed of a metal paste of the same material. 250) and auxiliary pads 244 and 245 are printed. The metal paste may be tungsten (W) or molybdenum / manganese (Mo / Mn) alloy.

Thereafter, the first ceramic layer 231 is sequentially stacked on the fourth ceramic layer 234 to fill metal pastes in the side grooves to form first to third conductive patterns 260a, 260b, and 260c. Sinter at the firing temperature. Alternatively, the metal paste may be filled in the side grooves before the ceramic layer is laminated.

After the sintering process, it is preferable to perform nickel plating on the electrode pad 250, the auxiliary pads 244 and 245, and the conductive patterns 260a, 260b, and 260c formed on the exposed surface of the auxiliary circuit board 230. Do.

On the other hand, the heat dissipation main substrate 210 may be manufactured in the structure described above by molding or pressing the metal material to be applied. Preferably, the heat dissipation main substrate 210 is formed by forming a metal plate made of copper, tungsten / copper alloy or brass having good thermal conductivity in the illustrated structure, and then nickel-plating the entire surface thereof.

As described above, the reflector 270 may be formed of a material having high reflectivity, for example, aluminum, or formed by forming a molded body with other metals or synthetic resins and then coating the surface with a material having high reflectivity.

When the reflector 270 is formed of a metal or a synthetic resin, and then the surface is coated with a material having a high reflectance, the molded object is first plated with nickel and then the bonding process described below is performed.

When the heat dissipation main board 210, the auxiliary circuit board 230, and the reflector 270 are prepared, they are bonded to each other.

Bonding between the heat dissipation main board 210, the auxiliary circuit board 230, and the reflector 270 may be performed at the same time or in any order.

For example, when the reflector 270 is to be formed by sequentially plating with nickel and silver, as shown in FIGS. 5 and 7, between the auxiliary circuit board 230 and the heat dissipation plate 210 and the auxiliary plate. Brazing sheets 280 and 283 are inserted between the circuit board 230 and the reflector 270, respectively, and then fused at temperatures above the melting point of the brazing sheets 280 and 283. . Here, the brazing sheets 280 and 283 may be formed of a silver / copper alloy or a gold / tin alloy material. Alternatively, a silver / copper alloy or a gold / tin alloy formed in a paste state may be joined by soldering.

When the assembly is completed as described above, the chip bonding pad 238, the heat dissipation main substrate 210, the conductive metal 250, the conductive pad 260, and the reflector 270 formed on the entire conductive metal, that is, the auxiliary circuit board 230. ) Is plated with nickel again.

Next, the chip bonding pad 238, the heat dissipation main substrate 210, and the reflector 270 are plated with silver.

Alternatively, the inner surface of the reflector 270 may be coated with at least one material of a reflecting material group including aluminum and bright nickel.

On the other hand, when the reflector 270 is formed of an aluminum material, the heat dissipation main board 210 and the auxiliary circuit board 230 are bonded to each other with a soldering agent, and nickel and sequential to the conductive metal of the bonded assembly are sequentially formed. After silver plating, the reflector 270 may be bonded to the auxiliary circuit board 230 with a binder such as epoxy.

When the package structure 200 is completed as described above, the LED chip 110 to be applied is mounted on the chip seat 212 of the heat dissipation main substrate 210 directly or through a submount (not shown). Then, the chip bonding pad 238 corresponding to the LED chip 110 is bonded with the wire 140. Alternatively, in the flip type LED chip, thermal conduction and fixing solder are applied to the chip mounting part 212, and electrical connection solder is applied to the chip bonding pad 238, and then the LED chip 110 is mounted.

Thereafter, the lens 120 is inserted into the reflector 270, and the sealing portion of the coupling part between the lens 120 and the reflector 270 is made of a sealing material, for example, an epoxy material, to manufacture the light emitting diode 100.

In the above description, the case where the light emitting diode chip is applied has been described, and it can be applied to various known light emitting semiconductor chips such as a laser diode chip.

As described so far, according to the surface-mounted light emitting device according to the present invention, the package structure and the manufacturing method thereof, it is possible to mount both the flip type light emitting diode chip and the top-epit type light emitting diode chip. It can be mounted on the main board for heat dissipation and is structured to focus light, thus providing the advantage of improving luminous efficiency and heat dissipation ability.

Claims (7)

A heat dissipation main substrate having a base portion and a chip seat portion protruding from the base portion at a predetermined height in a center portion of the base portion, and made of a heat dissipation material; It is bonded to the heat dissipation main board to surround the heat dissipation main board from the side of the base portion to the top surface so that the surface mounting is possible to expose the bottom surface of the heat dissipation main board and the chip seat. An auxiliary circuit board on which at least one electrode pad is formed, and at least one chip bonding pad electrically connected to the electrode pad at an upper surface thereof; And a reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip to be mounted on the chip seat. The surface mounted light emitting device package structure of claim 1, wherein an upper surface of the auxiliary circuit board is formed to be parallel to an upper surface of the chip seat. The surface mounted light emitting device package structure of claim 1, wherein the reflector has at least an inner surface formed of at least one of silver, nickel, and aluminum. A heat dissipation main substrate having a base portion and a chip seat portion protruding from the base portion at a predetermined height in a center portion of the base portion, and made of a heat dissipation material; It is bonded to the heat dissipation main board to surround the heat dissipation main board from the side of the base portion to the top surface so that the surface mounting is possible to expose the bottom surface of the heat dissipation main board and the chip seat. An auxiliary circuit board on which at least one electrode pad is formed, and at least one chip bonding pad electrically connected to the electrode pad at an upper surface thereof; At least one light emitting device chip mounted on the chip seat; A reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip mounted on the chip seat to the periphery; And And a cap coupled to shield the internal space between the reflector and the light emitting diode chip. 5. The surface mounted light emitting device according to claim 4, wherein the cap is a focusing lens bonded to the reflector. 5. The surface mounted light emitting device of claim 4, wherein an upper surface of the auxiliary circuit board is formed to be parallel to an upper surface of the chip seat. end. Forming a heat dissipation main board having a base portion and a chip seat portion protruding at a predetermined height from the base portion at a center portion of the base portion; I. An insertion hole formed to enclose the heat dissipation main substrate from the side of the base portion to the top surface of the heat dissipation main substrate to expose the bottom of the heat dissipation main substrate and the chip mounting portion, and at least one electrode pad on the bottom thereof; And forming an auxiliary circuit board having at least one chip bonding pad electrically connected to the electrode pad on an upper surface thereof. All. Bonding the auxiliary circuit board and the heat dissipation main board to the heat dissipation main board in the insertion hole; hemp. And bonding a reflector formed on the auxiliary circuit board to focus a beam diffused from the light emitting device chip to be seated on the chip mounting unit on the auxiliary circuit board.

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