Small size light emitting device and manufacturing method of the same

There is provided a light emitting device including: a package body having first and second circumferential surfaces and a plurality of side surfaces formed therebetween, the package body defined into first and second level areas including the first and second circumferential surfaces, respectively; first and second external terminal blocks each having an electrical contact part; an LED chip disposed between the first and second external terminal blocks in the first level area and having an electrode surface where first and second electrodes are formed; and wires electrically connected to first and second electrodes of the LED chip to the electrical contact parts of the first and second external terminal blocks, respectively.

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 having a semi-conductor light emitting diode (LED) chip and a method of manufacturing the same.

2. Description of the Related Art

In general, a light emitting device having a light emitting diode (LED) chip is structured as a package with a case obtained by injection-molding a white resin together with a lead frame. In this light emitting device, an LED chip is mounted on a groove of the case to connect to the lead frame and then the groove is filled with a resin. Particularly, to manufacture a white light emitting device, a phosphor powder may be added to the resin filled in the groove.

However, a conventional light emitting device entails drawbacks in terms of miniaturization and yield.

For example, a side view light emitting device, which is mainly used as a backlight source of a display of a mobile phone and can be surface mounted, greatly needs to be thinned in line with a thinner trend of the mobile phone. However, the conventional light emitting device should be provided with a groove for mounting LED chip therein, thus posing difficulty to the manufacture of a sufficiently smaller case having the LED chip thereon.

Besides, the conventional light emitting device is manufactured through a complicated process. That is, the case is injection-molded, with the lead frame disposed, the LED chip is mounted and a resin encapsulant is formed in the groove. This undermines yield and increases manufacturing costs.

Notably, in a white light emitting device, when a liquid resin containing a phosphor powder is dispensed, the phosphor may be injected unevenly due to the dispensing process.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a method of manufacturing a smaller light emitting device in which a light emitting diode (LED) chip and an electrode lead for external connection can be integrated through a single process unlike a conventional package process.

An aspect of the present invention also provides a novel light emitting device which can be manufactured in a smaller size and through a simpler process.

According to an aspect of the present invention, there is provided a method of manufacturing a light emitting device, the method including: providing a plurality of LED chips each having an electrode surface where both electrodes are formed, and a plurality of external terminal blocks, each of the external terminal blocks having an electrical contact part exposed on at least one surface; attaching the external terminal blocks and the LED chips on a first sheet such that the electrode surface and an exposed surface of the electrical contact part are located at a top and each of the LED chips is disposed between the external terminal blocks; connecting the electrodes of the LED chip to exposed surfaces of the electrical contact parts of adjacent ones of the external terminal blocks by wires, respectively; forming a chip array structure by attaching a spacer having a height greater than a height of the wires on the first sheet to surround an arrangement area of the external terminal blocks and the LED chips; disposing the chip array structure inside a chamber and decompressing the chamber inside to be in one of a low pressure and vacuum state; dropping a curable liquid resin to be filled in the arrangement area surrounded by the spacer; attaching a second sheet on the spacer when the curable liquid resin is filled inside the chip array structure; curing the curable liquid resin filled inside the chip array structure; and cutting the chip array structure into a desired size to obtain a plurality of light emitting devices.

According to another aspect of the present invention, there is provided a method of manufacturing a light emitting device, the method including: providing a plurality of LED chips each having an electrode surface where both electrodes are formed, and a plurality of external terminal blocks, each of the external terminal blocks having an electrical contact part exposed on at least one surface; attaching the external terminal blocks and the LED chips on a first sheet such that the electrode surface and an exposed surface of the electrical contact part are located at a top and each of the LED chips is disposed between the external terminal blocks; connecting the electrodes of the LED chip to exposed surfaces of the electrical contact parts of adjacent ones of the external terminal blocks by wires, respectively; attaching a spacer on the first sheet to surround an arrangement area of the external terminal blocks and the LED chips, the spacer having a height greater than a height of the wires and having at least one inlet formed therein; attaching a second sheet on the spacer to produce a chip array structure having an inner space including the arrangement area; disposing the chip array structure inside a chamber and decompressing the chamber inside to allow the inner space of the chip array structure to be in one of a low pressure and vacuum state; disposing a curable liquid resin in an area adjacent to the inlet of the spacer to seal the inner space thereof while the chamber is decompressed; reverting the one of the low pressure and vacuum state of the chamber back to an original state to allow the curable liquid resin to be filled in the inner space of the spacer through the inlet; curing the curable liquid resin filled inside the chip array structure; and cutting the chip array structure into a desired size to obtain a plurality of light emitting devices.

Each of the LED chips may include a transparent resin layer formed on at least one side surface thereof. The each of the LED chips may include transparent resin layers formed on the side surface and a surface opposing the electrode surface, respectively. A corresponding one of the transparent layers formed on the surface opposing the electrode surface may include a phosphor powder.

Before the chip array structure is diced into a desired size, a phosphor layer may be additionally formed on at least an area of the LED chip out of the exposed surface after removing the first sheet.

The method may further include removing the first and second sheets, between the curing the curable liquid resin and the cutting the chip array structure into a desired size.

The each of the external terminal blocks may include an insulating block having first and second surfaces opposing each other, the electrical contact part of the external terminal block may include a conductive via hole extending through the first and second surfaces of the insulating block, and the exposed surface of the electrical contact part may be the first surface of the insulating block.

To ensure wires to be connected in a sufficient area, the electrical contact part of the external terminal block may further include an electrode layer formed on the first surface of the insulating block to connect to the conductive via hole.

The insulating block may be a ceramic block or a printed circuit board (PCB) block. The insulating block, when formed of the ceramic block, may have a porous structure to be more strongly bonded to the resin.

The each of the external terminal blocks may have a side surface where at least one step is formed to be more superbly bonded to the light emitting device.

The cutting the chip array structure may include cutting the chip array structure together with the external terminal blocks so as to expose the conductive via hole.

The providing a plurality of LED chips and a plurality of external terminal blocks may include arranging the plurality of LED chips and the plurality of external terminal blocks in such a way that four of the LED chips share one of the external terminal blocks, and the cutting the chip array structure may include cutting the chip array structure together with the external terminal blocks in such a way that the conductive via hole is exposed at two side surfaces of adjacent ones of the insulating blocks, respectively.

The attaching the external terminal blocks and the LED chips on a first sheet may include: arranging the LED chips and the external terminal blocks on the first sheet having a curable material applied thereon; and curing the curable material such that the LED chips and the external terminal blocks are secured to each other on the first sheet.

The method may further include disposing the curable liquid resin inside the chamber, before the decompressing the chamber inside, whereby the curable liquid resin is de-aired in the decompressing the chamber inside.

The curable resin may include an electrically insulating high-reflectivity powder. The high-reflectivity powder may be a TiO2powder.

The method may further include: attaching a zenor diode on one of the external terminal block and the LED chip, after the attaching the external terminal blocks and the LED chips, wherein the connecting the electrodes by wires includes connecting the zenor diode, the electrical contact part of the external terminal block and the electrodes of the LED chip to one another by wires.

The method may further include attaching a heat radiator on the LED chip, after attaching the external terminal blocks and the LED chips.

The second sheet may be rigid. The external terminal block may have a height identical to a height of the spacer, the external terminal block may have a step formed on a surface facing the LED chip and may have a step surface electrically connected to a top end thereof.

The external terminal block may be formed of a conductor capable of serving as the electrical contact part.

According to still another aspect of the present invention, there is provided a light emitting device including: a package body having a first circumferential surface, a second circumferential surface and a plurality of side surfaces formed therebetween, the package body defined into first and second level areas including the first and second circumferential surfaces, respectively, and formed of a curable resin; first and second external terminal blocks disposed at both edges of the package body, respectively and each having first and second surfaces and side surfaces therebetween, each of the first and second external terminal blocks having the first surface exposed to the first circumferential surface of the package body and having an electrical contact part connected from inside of the package body to another exposed surface; an LED chip disposed between the first and second external terminal blocks in the first level area and having an electrode surface where first and second electrodes are formed, the electrode surface facing the second level area; and wires electrically connected to first and second electrodes of the LED chip to the electrical contact parts of the first and second external terminal blocks, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A method of manufacturing a light emitting device according to a first embodiment of the present invention will be more easily understood by way of exemplary processes shown inFIGS. 1 and 2.

FIGS. 1A to 1Dillustrate processes of manufacturing a chip array structure necessary for manufacturing a light emitting device according to a first embodiment of the invention.

As shown inFIG. 1A, external terminal blocks15and light emitting diode (LED) chips12are arranged on a first sheet11a′ having a curable material R applied thereon.

Each of the LED chips12has electrodes12aand12bof opposite polarities formed on one surface (hereinafter, “electrode surface”). As in the present embodiment, resin layers14may be formed on a surface opposing the electrode surface and side surfaces of each of the external terminal blocks15. The resin layers14may contain a phosphor powder for converting wavelength. Particularly, a phosphor-containing portion of the resin layers may be provided on a surface serving as a light exiting surface in the LED chip12, i.e., the surface opposite to the electrode surface.

The external terminal block15of the present embodiment includes an insulating block15aand an electrical contact part15bextending through both surfaces of the external terminal block and formed of a conductor. The electrical contact part15bis exposed on at least one surface of the external terminal block15to be brought in contact with the LED chip12. This external terminal block15is provided as an external terminal of a final light emitting device. A connection area for this external terminal can be attained by exposing the electrical contact part15bthrough a diced surface when diced in a later dicing process.

The shape of the external terminal block15, and position and shape of the electrical contact part15bmay be varied according to a structure of a desired final light emitting device, e.g., side view or top view light emitting device (seeFIGS. 7A,7B andFIG. 16).

The external terminal block15applicable to the present embodiment is not limited to a specific shape as long as provided with the electrical contact part15bexposed to connect to the electrodes12aand12bof the LED chip and exposed on a surface of the final light emitting device, i.e., after dicing. In a specific embodiment, the external terminal block may be formed of a conductor material to serve as the electrical contact part.

In the present embodiment, the LED chip12is disposed between the external terminal blocks15. To be connected by wires later, the LED chip12and the external terminal block15are arranged such that the electrode surface and an exposed surface of the electrical contact part15bare located at a top.FIG. 3illustrates arrangement applicable to an exemplary embodiment of the invention.

Referring toFIG. 3, an LED chip12is illustrated as LED chip arrays A arranged in a line. Each of these LED chip arrays A is construed as a structure where a resin layer14formed has not been diced into individual chips. Of course, alternatively, individual chips may be arranged in place of adopting the LED chip array.

In the arrangement, four LED chips12share one external terminal block15. Therefore, when diced along dotted lines in a following process, the external terminal block15is diced into quarters to produce four individual light emitting devices. Here, when the external terminal block15is diced into quarters, a conductive via hole, i.e., the electrical contact part15bis diced at the same time, thereby exposing the electrical contact part15bat two adjacent side surfaces formed by the dicing. The exposed surfaces of the electrical contact part can serve as a connection area for the external terminal block15. The external terminal of the light emitting device can be configured without being limited to the above. In alternative arrangement, two or other number of LED chips may share one external terminal block.

Thereafter, as shown inFIG. 1B, the LED chip12and the external terminal block15arranged on the first sheet11a′ are fixed to the first sheet11ausing an adhesive curable material R.

To perform this process, the LED chips12and the external terminal blocks15may be pressed adequately and then an adhesive curable material may be cured appropriately. For example, in a case where a curable material is an ultra violet (UV) curable resin, the ultra violet may be irradiated to attach the LED chips12and the external terminal blocks15on the first sheet11aafter performing pressing.

Then, as shown inFIG. 1C, the electrodes12aand12bof the LED chip12are connected to the exposed surfaces of the electrical contact parts15bof adjacent ones of the external terminal blocks15by wires, respectively.

In the arrangement process described above (seeFIG. 1A), the LED chip12and the external terminal block15are arranged such that the electrode surface and the exposed surface of the electrical contact part15bare provided on a top. Thus this wire-bonding process can be performed easily.

Next, as shown inFIG. 1D, a spacer17is attached on the first sheet11ato surround an arrangement area defined by the external terminal blocks15and the LED chips12.

The spacer17defines an area where the resin is filled in a following process of filling the resin. Therefore, to ensure the wires16aand16bto be positioned inside a package body formed of the resin, the spacer17has a height greater than a height of the wires16A and16B. The spacer17can be attached using an adhesive resin or a curable material.

These processes allow for a chip array structure applicable to the first embodiment of the present invention. The chip array structure shown inFIG. 1Dcan be manufactured into a plurality of light emitting devices through a series of processes such as filling of resin and dicing as shown inFIGS. 2A to 2D.

First, as shown inFIG. 2A, a curable liquid resin18′ is dropped onto the arrangement area inside the spacer17to fill the arrangement area surrounded by the spacer17.

The curable liquid resin18′ may be dropped in a sufficient amount to fill an inner space of the spacer. More specifically, the curable liquid resin18′ may be dropped to at least a height of the spacer17.

The curable liquid resin18′ may be a transparent resin containing an electrically insulating and high-reflectivity powder to prevent loss from light absorption by other components and enhance light radiation efficiency. The high-reflectivity powder may be a TiO2powder. The transparent resin may adopt a silicon resin, an epoxy resin and a combination thereof.

The dropped resin18′ can be adequately positioned between the LED chips12and the external terminal blocks15by adjusting conditions such as viscosity of the resin.

In the present embodiment, to fill the resin, the chip array structure is disposed in a vacuum chamber and the chamber is decompressed to be in a low pressure or vacuum state. For example, this process can be performed in a vacuum chamber shown inFIGS. 4A and 4B.

As shown inFIGS. 4A and 4B, a vacuum chamber apparatus30includes a chamber31, a vacuum valve36provided at one side of the chamber31and a shelf33provided inside the chamber31.

The chamber31has an inner space decompressed through a vacuum valve36to be in a vacuum or low pressure state. The chamber31may additionally include a resin storage34to drop the curable liquid resin18′ onto a desired location. The resin storage34assures de-airing of the curable resin18′, which is to be filled under this decompression condition.

Before decompressing the inside of the chamber31, the curable liquid resin may be previously positioned inside the chamber31to be more effectively de-aired.

Thereafter, as shown inFIG. 2B, the chamber31is reverted to its original state and then a second sheet11bis attached onto the spacer17.

When the second sheet11bis attached on the spacer17, the curable liquid resin18′ can be adjusted in level to be equivalent to a height of the spacer17. Moreover, an appropriate pressure may be applied when the second sheet11bis attached, thereby allowing the curable liquid resin18′ to be injected into an area between the LED chips12and external terminal blocks15more effectively. This process along with other following processes may be carried out while the chip array structure is unloaded after the chamber is reverted to its originals state.

Thereafter, as shown inFIG. 2C, the curable liquid resin18′ filled inside the chip array structure is cured.

The curing can be performed by using heat or ultraviolet ray irradiation depending on type of the resin. In this process, the curing may be directly performed inside the chamber31. Alternatively, the chip array structure may be picked up and cured using an additional pressing apparatus P outside. The cured resin18secures the LED chips12and the external terminal blocks15together to form a single structure. Also, the cured resin may protect the wires16electrically connecting the chips12and the blocks15.

Subsequently, as shown inFIG. 2D, the first and second sheets11aand11bare removed from the chip array structure, and the chip array structure is diced into a desired size to produce a plurality of light emitting devices10.

The first and second sheets11aand11bcan be removed from the chip array structure by a suitable chemical and mechanical method known in the art. After the sheets11aand11bare removed, the chip array structure is diced by a dicing apparatus D.

In the arrangement ofFIG. 1AandFIG. 3, the chip array structure is diced into quarters so that the divided external terminal blocks15serve as external terminals for four light emitting devices, respectively. Also, the chip array structure may be diced in such a way that the electrical contact part15bis exposed at two adjacent side surfaces through a diced surface of the external terminal blocks15.

FIG. 5Ais a plan view andFIG. 5Bis a side cross-sectional view illustrating a light emitting device, respectively according to a first embodiment of the present invention.

Referring toFIGS. 5A and 5B, the light emitting device20includes a package body28formed of a curable resin. The package body28has first and second circumferential surfaces28aand28bopposing each other and a side surface28cdisposed therebetween. The first and second circumferential surfaces28aand28band the side surface28cof the package body28are planar. In the present embodiment, each of the surfaces of the package body is planar but may be varied through additional machining.

The package body28may be a transparent resin containing an electrically insulating and high-reflectivity powder to reduce loss from light absorption by other components. The high-reflectivity powder may adopt a TiO2powder.

First and second external terminal blocks25are disposed at both edges of the package body28. Each of the first and second external terminal blocks25includes a first surface exposed to the first circumferential surface28aof the package body28and a second surface opposing the first surface. The external terminal block25of the present embodiment includes an insulating block25aand an electrical contact part25bextending through the first and second surfaces.

To explain the structure of the light emitting device20of the present invention more easily, the package body28is construed to be divided into first and second level areas L1and L2including the first and second circumferential surfaces28aand28b, respectively based on an electrode surface of the LED chip22where the electrodes22A and22B are formed.

The LED chip22is located between the first and second external terminal blocks25in the first level area L1and the electrode surface where the first and second electrodes22aand22bare formed faces the second level area L2. The LED chip22can be connected to a portion of the connector25bexposed to the second surface of each of the first and second external terminal blocks25by wires26aand26b. Also, the wires26can be located in the second level area L2and across a portion L1of the first level area of the package body28to be protected.

In the present embodiment, as described regarding the arrangement shown inFIG. 3and the dicing process ofFIG. 2D, the each external terminal block25may be diced into quarters so that the electrical contact part25bis exposed at two adjacent diced surfaces. Here, a side surface of the package body28where the electrical contact part25bof the external terminal block25is exposed serves as an area where the light emitting device20is mounted. The light emitting device20with this structure can be very effectively utilized as a side view LED package.

Particularly, the light emitting device20of the present embodiment does not employ an additional case structure, thereby realizing sufficient compactness. Moreover, unlike a conventional method entailing an additional process of forming a resin encapsulant aside from a process of injection-molding the case structure, the whole structure can be manufactured in a single process and does not require additional machining for a lead frame. This advantageously allows compact packages to be mass-produced.

The light emitting device of the present embodiment may be varied depending on a desired package structure. For example, a necessary component can be adequately added. As a representative example, the light emitting device may include a heat radiator for radiating heat effectively and/or a zenor diode for voltage resistance characteristics.

FIG. 6Ais a plan view andFIG. 6Bis a side cross-sectional view illustrating a light emitting device, respectively according to another exemplary embodiment of the present invention.

Referring toFIG. 6AandFIG. 6B, in a similar manner to the light emitting device20shown inFIGS. 5A and 5B, the light emitting device30includes a package body38and first and second external terminal blocks35disposed at both edges of the package body38. The light emitting device30also includes an LED chip32disposed between the first and second external terminal blocks.

The LED chip32is located in a first level area L1, and first and second electrodes32aand32bmay be connected to an electrical contact part35bof each of the first and second external terminal blocks35by wires36aand36b, respectively. Furthermore, the wires36aand36bcan be located in a second level area L2of the package body38to be protected.

The light emitting device30of the present embodiment includes a zenor diode37disposed on one of the external terminal blocks35in the second level area L2. The zenor diode37can be electrically connected to the LED chip32by wire-bonding or surface mount technology. That is, as in the present embodiment, the zenor diode37has one electrode connected to the electrical contact part35bof one of the external terminal blocks35by surface mount technology. Also, the zenor diode37has another electrode connected to the electrical contact part35bof the other external terminal block35by wires36c.

Alternatively, the zenor diode37may be bonded with different configurations depending on location of the electrodes and mounting position thereof. For example, alternatively, the zenor diode37may be mounted on an electrode surface of the LED chip32. Here, the zenor diode37may have both electrodes connected to the electrical contact part by wires, respectively.

In addition, the light emitting device30may further include a heat radiator39located in the second level area L2and attached on the LED chip32. The heat radiator39may be formed of a known material having excellent thermal conductivity.

As described above, optionally, the light emitting device30may include the zenor diode37and/or the heat radiator39. This process can be performed by a manufacturing process of the chip array structure shown inFIGS. 1A to 1D. Such a process may be performed before the wires bonding process (FIG. 1C).

FIGS. 7A and 7Bare perspective views illustrating an external terminal block applicable to the first embodiment of the present invention. Here, the external terminal block is applicable to the arrangement ofFIG. 3and a final light emitting device may be divided into quarters along dotted lines. Alternatively, the external terminal block may be configured as a board shown inFIG. 9.

An external terminal block45ofFIG. 7Aincludes an insulating block45a. This insulating block45amay be formed of a ceramic body. Notably, the ceramic body may be formed of a porous structure having a plurality of pores h to be more highly bonded to a resin of the package body. To this end, the insulating block45aof the porous structure may have a porosity of about 10 to 60% and a pore diameter of about 0.1 to 1.3 μm.

An electrical contact part45B of the external terminal block45may include a conductive via hole V1extending through both surfaces of the insulating block45and an electrode layer E1connected to the conductive via hole V1. Here, the electrode layer E1allows electrodes of the LED chip to be wire-bonded thereto in a greater bonding area, thereby diminishing defects associated with bonding.

When the conductive via hole V1is formed, optionally, a metal layer M made of Au or Ag may be formed on the external terminal block45. This metal layer M absorbs light generated from the LED chip inside the package structure, potentially degrading optical efficiency. To prevent this, the external terminal block45may further include a light absorption prevention layer46to at least cover the metal layer M. The light absorption prevention layer46may be formed of a resin layer containing a high-reflectivity powder such as TiO2.

An external terminal block55shown inFIG. 7Bincludes an insulating block55a. This insulating block55ahas a step S provided at a side surface of the external terminal block55. In a similar manner to the porous structure described above, this step S structure can be more highly bonded to the resin of the package body.

The electrical contact part55bof the external terminal block55may include a via hole V2extending through both surfaces of the insulating block55and an electrode layer E2connected to the conductive via hole V2. Here, the electrode layer E2ensures electrodes of the LED chip to be wires-bonded thereto in a greater bonding area, thereby diminishing defects associated with bonding.

FIGS. 8A to 8Dare cross-sectional views illustrating a manufacturing process of a chip array structure in a method of manufacturing a light emitting device according to a modified example of the first embodiment of the invention.

As shown inFIG. 8A, external terminal blocks65and LED chips62are arranged on a first sheet61a′ having a curable material R applied thereon.

Each of the LED chips62is provided with an electrode surface where electrodes62aand62bof opposite polarities are formed. In the present embodiment, unlike the embodiment ofFIG. 1, a resin layer is not additionally formed on a surface of the LED chip62.

Similarly toFIG. 1, each of the external terminal block65may include an insulating block65a, and an electrical contact part65bextending through both surfaces of the external terminal block and formed of a conductor. The external terminal block is diced in a later dicing process (seeFIG. 2E) and the electrical contact part65bmay be exposed at a diced surface to ensure a connection area for the external terminal block.

In the present embodiment, the LED chip62is disposed between the external terminal blocks15. The LED chip62and the external terminal block65are arranged such that the electrode surface and an exposed surface of the electrical contact part65bare located at a top.

In the arrangement of the present embodiment, as shown inFIG. 9, an external terminal block65is configured as a board. This external terminal block65can be easily manufactured by adopting a printed circuit board (PCB). Also, when diced along dotted lines in a later process, an electrical contact part65bof the external terminal block65is diced into quarters to act as four respective light emitting devices. Here, the electric contact part65bmay be exposed on two adjacent side surfaces formed by the dicing to ensure a connection area for external terminals. The external terminals for the light emitting devices may be formed by the method described above but not limited thereto. In alternative arrangement, two or other number of LED chips may share the external terminal block.

Thereafter, as shown inFIG. 8B, the LED chip62and the external terminal block65arranged are attached on the first sheet61ausing an adhesive curable material R.

The LED chips62and the external terminal blocks65can be attached on the first sheet61aafter appropriately pressing the LED chips62and the blocks65and performing curing with the adhesive curable material.

Next, as shown inFIG. 8C, the electrodes62aand62bof the LED chip62are connected to exposed surfaces of the electrical contact parts of adjacent ones of the external terminal blocks65by wires, respectively.

Afterwards, as shown inFIG. 8D, a spacer67is attached on the first sheet61ato surround an arrangement area of the external terminal blocks65and the LED chips62.

To ensure the wires66A and66B to be positioned inside a package body formed of the resin, the spacer67has a height greater than a height of the wires66aand66b. The spacer67can be attached using an adhesive resin or a curable material.

These processes allow for a chip array structure applicable to the present embodiment. The chip array structure shown inFIG. 8Dcan be manufactured into a plurality of light emitting devices through a series of processes such as filling of resin and dicing as shown inFIGS. 9A to 9E.

Unlike the embodiment ofFIG. 1, the LED chip62of the present embodiment does not include a resin layer formed on a surface thereof. The light emitting device may require formation of a phosphor layer for converting wavelength. Therefore, the present embodiment suggests a novel process of forming a phosphor layer. This process can be understood by way of processes shown inFIGS. 10A to 10E.

First, as shown inFIG. 10A, a curable liquid resin68′ is dropped onto an arrangement area inside a spacer67to be filled in the arrangement area surrounded by the spacer67.

The curable liquid resin68′ may be dropped in a sufficient amount to fill an inner space of the spacer. Particularly, the curable liquid resin68′ may be dropped to at least a height of the spacer67.

In the present embodiment, to fill the resin, a chip array structure is disposed in a vacuum chamber and the chamber is decompressed to be in a low pressure or vacuum state. For example, in a similar manner to the embodiment shown inFIG. 1, this process can be performed using the vacuum chamber shown inFIG. 4AandFIG. 4B.

The curable liquid resin of the present embodiment may have low refractivity to prevent light form being guided into the package body and facilitate light extraction in a desired direction. The curable liquid resin may utilize a transparent liquid resin having a refractivity of about 1.5 or less.

Thereafter, as shown inFIG. 10B, the chamber is reverted back to its original state and then a second sheet61bis attached onto the spacer67.

When the second sheet61bis attached on the spacer67, the curable liquid resin68′ can be adjusted in level to be equivalent to a height of the spacer67. Moreover, an appropriate pressure may be applied when the second sheet61bis attached, thereby allowing the curable liquid resin68′ to be injected into an area between the LED chips62and external terminal blocks65more effectively. This process along with other following processes may be carried out while the chip array structure is unloaded after the chamber is reverted back to its original state.

Next, as shown inFIG. 10C, the curable liquid resin68′ filled inside the chip array structure is cured.

The curing can be performed by using heat or irradiating ultraviolet ray depending on type of the resin. In this process, the curing may be directly performed inside the chamber. However, as in the present embodiment, the chip array structure may be picked up and cured using an additional pressing apparatus P outside. The cured resin68secures the LED chips62and the external terminal blocks65together to form a single structure. Also, the cured resin68can protect wires66A and66B electrically connecting the chip62to the block65to each other.

Subsequently, as shown inFIG. 10D, the first and second sheets61aand61bare removed from the chip array structure, and a phosphor layer69is formed on an exposed surface of the LED chip where the first sheet61ais removed.

The first and second sheets61aand61bcan be removed from the chip array structure by a suitable chemical and mechanical method known in the art. The phosphor layer69is formed on a light exiting surface, i.e., an area corresponding to at least the LED chip62.

Thereafter, as shown inFIG. 10E, the chip array structure is diced into a plurality of light emitting devices60.

The dicing can be performed by a suitable dicing apparatus. As in the present embodiment, when four LED chips62share one external terminal block65, the external terminal block65is diced into quarters to act as respective light emitting devices60. Here, a conductive via hole, which is the electrical contact part65b, is diced together with the external terminal block65to expose the electrical contact part65bat two adjacent side surfaces. The exposed surface of the electrical contact part may serve as an area for connecting the external terminal.

FIG. 11Ais a plan view andFIG. 11Bis a side cross-sectional view illustrating a light emitting device according to another exemplary embodiment of the invention.

Referring toFIGS. 11A and 11B, the light emitting device70includes a package body78formed of a curable resin. The package body78has first and second circumferential surfaces78aand78bopposing each other and a side surface78cdisposed therebetween. The first and second circumferential surfaces78aand78band the side surface78cof the package body78are planar.

First and second external terminal blocks75are disposed at both edges of the package body78. Each of the first and second external terminal blocks75includes a first surface exposed to the first circumferential surface78aof the package body78and a second surface opposing the first surface. The external terminal block75of the present embodiment includes an insulating block75aand an electrical contact part75bextending through the first and second surfaces.

The LED package body78is construed to be divided into first and second level areas L1and L2including the first and second circumferential surfaces78aand78b, respectively based on a surface of the LED chip72where the electrodes72aand72bare formed.

The LED chip72is located between the first and second external terminal blocks75in the first level area L1and an electrode surface where the first and second electrodes72aand72bare formed faces the second level area L2. The LED chip72can be connected to a portion of the electrical contact part75bexposed to the second surface of each of the first and second external terminal blocks75by wires76aand76b.

Also, the wires76can be positioned in the second level area L2of the package body78to be protected. A surface of the LED chip72opposite to the electrode surface is exposed to the first circumferential surface78a. The first circumferential surface78aof the package body78is provided as a light exiting surface. A phosphor layer is provided on the first circumferential surface78aof the package body to include at least the LED chip72.

The curable resin of the package body78may have low refractivity to prevent light generated from the LED chip72from being guided into the package body78and facilitate extraction of light toward the phosphor layer79. The curable resin may utilize a transparent resin having a refractivity of about 1.5 or less.

Furthermore, as shown inFIGS. 11A and 11B, the light emitting device70further includes side reflective layers74formed on two opposing side surfaces of the light emitting device70to at least cover an area where the LED chip72is positioned. The side reflective layers74are formed mainly on the side surfaces where the external terminal block is not disposed to thereby block light from propagating to a side of the package body78. The side reflective layers74may be formed of a resin containing a high-reflectivity power such as TiO2.

In the present embodiment, the external terminal block75is structured such that the electrical contact part75bis exposed at two adjacent diced surfaces. Here, a side surface of the package body78where the electrical contact part75bof the external terminal block75is exposed serves as an area where the light emitting device70is mounted. The light emitting device70with this structure can be very effectively utilized as a side view LED package. Moreover, the external terminal block may be variously modified in structure.

For example, as shown inFIG. 9, when the external terminal block configured as a board is employed, the external terminal block of a final individual light emitting device may be exposed to three adjacent ones of the side surfaces of the package body, as shown inFIG. 11A.

Alternatively, when the external terminal block15shown inFIG. 3is employed, the external terminal block of the final individual light emitting device may be exposed to two adjacent ones of the side surfaces of the package body, as shown inFIG. 12. Also, a corresponding one of the side surfaces of the package body where the electrical contact part of the external terminal block is exposed serves as an area where the light emitting device is mounted. Particularly, in the present embodiment, the electrodes are not exposed on a corresponding one of the side surfaces opposing the mounting surface of the light emitting device. This accordingly prevents short of the package resulting from a metal cover placed after setting.

Unlike the aforesaid first embodiments, the second embodiment of the present embodiment employs a novel process of filling a resin by vacuum suction.FIGS. 13A to 13Eare cross-sectional views illustrating a manufacturing process of a chip array structure in a method of manufacturing a light emitting device according to a second embodiment of the invention.

First, as shown inFIG. 13A, external terminal blocks85and LED chips82are arranged on a first sheet81a′ having a curable material R applied thereon.

Each of the LED chips82has an electrode surface where electrodes82A and82B of opposite polarities are formed. The LED chip82may include resin layers84formed on a surface opposite to the electrode surface and a side surface, respectively. The resin layers84may include a phosphor powder for converting wavelength. Particularly, a phosphor-containing portion of the resin layers may be provided on the surface opposite to the electrode surface, which will serve as a light exiting surface of the LED chips82.

The external terminal block85of the present embodiment is formed of a conductor block having a step structure. A step surface85aof the external terminal block85is connected to electrodes82aand82bof the LED chip82. Also, a top end85bof the external terminal block85serves as a connection area for a final light emitting device. To this end, the external terminal block may have a thickness identical to a height of the final light emitting device.

The LED chips and external terminal blocks of the present embodiment are arranged in a similar manner to those of the first embodiment.

Thereafter, as shown inFIG. 13B, the LED chip82and the external terminal block85arranged on the first sheet81a′ are attached by curing an adhesive material R on the first sheet81a.

To perform this process, the LED chips82and the external terminal block85may be pressed adequately and then an adhesive curable material may be cured. For example, in a case where a curable material is an ultraviolet ray (UV) curable resin, the ultraviolet ray may be irradiated to attach the LED chips82and the external terminal blocks85. In the present embodiment, the adhesive curable material is additionally applied but the first sheet81amay be a curable resin.

Next, as shown inFIG. 13C, the electrodes82A and82B of each of the LED chips82are connected to adjacent ones of the external terminal blocks85.

In each of the external terminal blocks85of the present embodiment, a portion connected to the LED chip82serves as a step surface85a. The step surface85aof the external terminal block85as well as the electrode surface is arranged to be located at a top, thereby facilitating wires bonding. Moreover, in the present embodiment, the external terminal block85is formed of a conductive material. This accordingly allows a top end85bto be exposed in a final package to be electrically connected to the step surface. Therefore, the top end85bof the external terminal block85can serve as an area where the final light emitting device is connected to the outside.

Thereafter, as shown inFIG. 13D, a spacer87is disposed to surround the LED chip82and the external terminal block85and provided with at least one inlet (I inFIG. 16). A second sheet81bis attached on the spacer87.

The spacer87has a predetermined height and together with the first and second sheets81aand81b, defines an inner space of the chip array structure. The spacer may have a height equivalent to a thickness of the final light emitting device. In the present embodiment, the spacer has a height substantially identical to a thickness of the external terminal block.

As shown inFIG. 16, the inner space of the chip array structure has two inlets I formed on opposing side walls to be connected to the outside. The inlets I serve as a supply conduit of a resin surrounding a surface of the LED chip in a later process.

As in the present embodiment, the plurality of inlets I are formed on the opposing sides to thereby ensure smoother injection of the resin. However, in the present invention, the inlets I are not limited in number or position and only a single inlet may be sufficient depending on size of the arrangement area and arrangement spacings.

The chip array structure shown inFIG. 13Dmay have the resin filled therein using a vacuum chamber shown inFIGS. 17A and 17B.

FIG. 17Ais a cross-sectional view andFIG. 17Bis an internal plan view illustrating a vacuum chamber applicable to the present invention, respectively.

As shown inFIGS. 17A and 17B, the vacuum chamber apparatus includes a chamber91, a vacuum value96provided at one side of the chamber91and a shelf disposed inside the chamber91. The inner space of the chamber91is decompressed via a vacuum valve96to be changed into a vacuum or low pressure state.

A resin storage94is disposed on a top of the chamber91to drop a curable liquid resin88′ onto a desired location. In the present embodiment, as shown, the resin storage94may be disposed in a portion adjacent to the inlets I to allow the inlets I of the spacer87to be sealed.

Hereinafter, with reference toFIG. 14A to 14D, an exemplary method of manufacturing chip parts will be described according to a second embodiment. The present embodiment is construed to be implemented based on the vacuum chamber shown inFIGS. 17A and 17B, and the method will be described in greater detail with reference toFIGS. 14A and 14B.

As shown inFIG. 14a, with a chip array structure disposed inside a chamber91, the chamber has an inner space changed into a vacuum or low pressure state via a vacuum valve96. Also, a curable liquid resin88′ is dropped onto inlets I of the spacer87.

The chamber91may be changed into a vacuum state inside by the decompression process, but may be in an adequate low pressure state to ensure a resin described below to be sucked. By this decompression process, not only the inner space of the chamber91but also the inner space of the chip array structure can be changed to be under the same pressure through the inlets I.

In the decompression process, the curable liquid resin88′ is previously disposed inside the chamber91to be de-aired. This precludes a need for an additional process for de-airing the liquid resin88′.

Afterwards, as shown, the curable liquid resin88′ is dropped in a sufficient amount to cover the inlets I, thereby substantially sealing the inner space of the chip array structure.

Then, the chamber is reverted back to its original state by a vacuum value96. This produces a chip array structure having the curable liquid resin88′ filled in an inner space thereof as shown inFIG. 14b.

In this process, the chamber91is drastically increased in inner pressure but the inner space of the chip array structure can maintain a low pressure or vacuum state by the curable liquid resin88′ sealing, even if temporality, the inlets I. This accordingly leads to high pressure difference between the inner space of the chip array structure and other outer space, i.e., inner space of the chamber91. This pressure difference allows the curable liquid resin88′ to be injected into the inner space of the chip array structure through the inlets I and be filled in the inner space, as indicated with arrows ofFIG. 14A. In this process, to ensure the resin88′ to be filled more effectively, viscosity of the resin, and position, shape and amount of the dropped resin may be adjusted.

Thereafter, as shown inFIG. 14C, the curable liquid resin88′ filled in the inner space of the chip array structure is cured. This curing can be performed using heat or ultraviolet ray irradiation depending on type of resin. The curing may be directly performed inside the chamber91, but the chip array structure may be picked up to be cured outside the chamber91by an additional curing apparatus P. The cured resin88may be present on all surfaces excluding a first surface82aof the LED chip82protected by the first sheet81a.

Finally, the first and second sheets81aand81bare removed from the chip array structure and the chip array structure is diced into a desired size to obtain a plurality of light emitting devices80.

The first and second sheets81aand81bmay be removed from the chip array structure by appropriate chemical and mechanical methods known in the art. After the sheets81aand81bare removed, the chip array structure is diced using a dicing apparatus D.

In the manufacturing method of the present embodiment, the curable liquid resin is injected in a vacuum state. The resin injected in a vacuum state (seeFIG. 14A) allows pressure to be imposed on the chip array structure. Thus, the second sheet should be supported by the external terminal block. Accordingly, the external terminal block may have a height equivalent to a height of a package.

Of course, in a case where the second sheet is formed of a rigid material which does not undergo warping without an additional support structure even at a pressure applied when the resin is injected in a vacuum state, this process of filling the resin by vacuum suction may be beneficially applied to a light emitting structure employing the external terminal block having a low height as shown inFIGS. 1 and 8.

In the light emitting device of the present embodiment, the external terminal block has a height identical to a height of the light emitting device and a step provided on a side surface thereof. Therefore, a step surface of the external terminal block is connected to the LED chip through wires. Also, a top end of the external terminal block may be exposed to serve as a connection area for the external terminal block. This structure can be advantageously utilized as a top view light emitting package structure.

FIG. 15Ais a plan view andFIG. 15Bis a cross-sectional view illustrating a light emitting device obtained by a manufacturing method ofFIGS. 13 and 14, respectively.

Referring toFIGS. 15A and 15B, the light emitting device100includes a package body108formed of a curable resin. The package body108has first and second circumferential surfaces108aand108bopposing each other and a side surface108cdisposed therebetween. The first and second circumferential surfaces108aand108band the side surface108cof the package body108are planar.

The package body108may be a transparent resin containing electrically insulating and high-reflectivity powder to reduce loss from light absorption by other components. The high-reflectivity powder may adopt a TiO2powder.

First and second external terminal blocks105are disposed at both edges of the package body108. Unlike the first embodiment, in the present embodiment, the first and second external terminal blocks105each have a height identical to a height of the package body108and a step is formed on a side surface facing an LED chip102. Also, the first and second external terminal blocks105may be formed of a conductive material. Therefore, a step surface105awhich is to be connected to LED chips102and a top end105bexposed to the second circumferential surface108bof the package body may be electrically connected to each other.

To explain the structure of the light emitting device100of the present embodiment more easily, the package body108is construed to be divided into first and second level areas L1and L2including the first and second circumferential surfaces108aand108b, respectively based on a surface of the LED chip102where electrodes102aand102bare formed.

The LED chip102is located between the first and second external blocks105in the first level area L1and an electrode surface where the first and second electrodes102aand102bare formed faces the second level area L2. The LED chip102may be connected to step surfaces105aof the first and second external terminal blocks105by wires106aand106b, respectively. Also, the wires106aand106bcan be located in the second level area L2of the package body108to be protected.

In the light emitting device of the present embodiment, a top end105bof the external terminal block exposed to the second circumferential surface108bof the package body108serves as an area where the light emitting device is connected to the outside. This accordingly allows the light emitting device to be bonded by surface mount technology so that the second circumferential surface108bof the package body108can serve as a mounting surface. The light emitting device100of this structure can be very effectively used as a top view LED package.

In present embodiment, the external terminal block105is configured such that the second circumferential surface108bopposing the first circumferential surface108aprovides an area where the light emitting device can be connected to an external circuit. To realize this structure, as described above, the external terminal block105has a height identical to a height of the package body108and has a step formed on a side surface thereof to serve as an area for connecting the LED chip102.

This external terminal block may be varied in structure.FIG. 18Ais a top plan view andFIG. 18Bis a side cross-sectional view illustrating an external terminal block applicable to the second embodiment of the invention.

The external block115shown inFIGS. 18A and 18Bis divided into quarters along dotted lines to be used as respective external terminals in an individual package.

The external terminal block115includes an insulating block115ahaving a height substantially identical to a height of the package body and provided with a step facing an LED chip. The insulating block115amay be formed of a porous ceramic body having a plurality of pores h to be more strongly bonded to the package body made of resin. As described above, to assure stronger bonding, the pores may have a porosity of about 10 to 60% and a pore diameter of about 0.1 to 1.3 μm.

A step surface of the block115is located inside the package body to be connected to electrodes of the LED chip. The block115has a top end exposed to a mounting surface of the package body to connect to an external circuit. To realize such an external terminal structure, an electrode layer115bis formed on the top end of the external terminal block115along the step surface of the external terminal block115to electrically connect the LED chip to the exposed top end.

As set forth above, according to exemplary embodiments of the invention, an additional case is not employed to achieve a sufficiently compact and novel light emitting device. Also, unlike a conventional technology entailing a process of forming a resin encapsulant in addition to a process of injection-molding the case, a whole structure is manufactured in a single process, and an additional machining process for a lead frame is not required. This beneficially allows for mass production of compact packages. Moreover, the light emitting device can be sized uniformly by suitably designing a chip array structure to ensure precise processes, thereby producing a higher-quality light emitting device with more efficiency.