TW201514591A - Light source module, fabrication method therefor, and backlight unit including the same - Google Patents

Abstract

A light source module, a fabrication method therefore, and a slim backlight unit including the same. The light source module includes a light emitting diode (LED) chip electrically connected to a substrate through a lower surface thereof, a wavelength conversion layer formed on the LED chip and enclosing at least the light exit face of the LED chip, and a reflector formed on a region of the LED chip excluding the light exit face.

Description

Light source module, manufacturing method thereof and backlight unit including the same [Cross-Reference to Related Applications]

The priority and interest of Korean Patent Application No. 10-2013-0114736, filed on Sep. 26, 2013, and Korean Patent Application No. 10-2014-0123053, filed on Sep. The application is hereby incorporated by reference in its entirety for all purposes as if it is fully incorporated herein.

The present invention relates to a light source module, a method of fabricating the same, and a backlight unit including the same, and more particularly to a light source module having excellent luminous efficiency, a method of manufacturing the same, and a method including the same. Slim backlight unit.

In general, backlight units are widely used to provide light to display elements such as liquid crystal display (LCD) elements or surface light emitting elements.

The backlight unit provided to the LCD element is mainly depending on the position of the light emitting element It is divided into a direct type and an edge type.

Direct-type backlight units have been developed primarily with large screen LCDs of 20 inches or more, and are characterized in that a plurality of light sources disposed below the diffuser plate emit light directly toward the front surface of the LCD panel. These direct type backlight units are mainly used for large screen LCD elements requiring high brightness because they have higher luminous efficiency than edge type backlight units.

The edge-emitting type backlight unit is used for a relatively small LCD element such as a laptop computer and a monitor of a desktop computer, and has excellent light uniformity, long life, and is suitable for LCD due to slimness. Advantages in components.

1 is a cross-sectional view of a typical light emitting diode (LED) package and a backlight unit including the same. Referring to Fig. 1, in the prior art, an LED package 10 is mounted on a side surface of a backlight unit. In this case, the slimness of the backlight unit is limited due to the height corresponding to the width of the LED package.

Current spreading reduces the efficiency of the LED package when the LED package has a reduced width to overcome this limitation. Therefore, although the thinning of the backlight unit is limited due to the LED package as described above, the user still needs a slimner backlight unit. Therefore, there is a need for an edge-emitting backlight unit that includes a novel LED package.

The present invention is directed to an edge-emitting thin backlight unit implemented by mounting a light emitting diode (LED) wafer side by side with a light guiding plate.

Furthermore, the present invention is directed to providing a light source module, a method of manufacturing the same, and a backlight unit of the light source module, wherein a wavelength conversion layer is formed on a side surface of the LED wafer facing the light guide plate, and then the LED wafer is removed except for the side surface of the LED wafer A reflector is formed on the region, and the light exit path is directed toward the light guide plate, thereby improving the light-emitting efficiency of the LED wafer when the LED wafer is mounted side by side with the light guide plate.

Furthermore, the present invention is directed to a light source module, a method of fabricating the same, and a backlight unit including the same, wherein an underfill comprising a reflective material is formed between the LED wafer and the substrate to prevent generation from the LED wafer. Light is emitted through other faces than the designated light exit face and concentrates the light on the light exit face, thereby improving luminous efficiency.

Furthermore, the present invention is directed to a light source module, a method of fabricating the same, and a backlight unit including the same, wherein the underfill is formed such that a reflective material is not applied to the light exit surface, thereby exiting the light exit path The barrier is removed and the distance between the LED wafer and the light guide plate is reduced to increase luminous efficiency.

According to an aspect of the present invention, a light source module includes: a light emitting diode (LED) wafer electrically connected to a substrate via a lower surface thereof, and including a light exit surface formed on one side surface thereof so that The light of the LED wafer is emitted via the light exit surface; a wavelength conversion layer is formed on the LED wafer and encloses at least the light exit surface of the LED wafer; and a reflector is formed in addition to the light exiting On the area of the LED chip outside the face.

The light source module may further include an underfill interposed between the substrate and the LED wafer and comprising a reflective material.

The reflective material may comprise a material selected from the group consisting of TiO ₂ , SiO ₂ , ZrO ₂ , PbCO ₃ , PbO, Al ₂ O ₃ , ZnO, Sb ₂ O _{3 ,} and combinations thereof.

The underfill may comprise a phosphor material.

The LED wafer can be mounted on the substrate by flip chip bonding or surface mount technology (SMT).

The LED chip may include: a first semiconductor layer doped with a first conductivity type impurity; an active layer formed under the first semiconductor layer; and a second semiconductor layer doped with a second conductivity type impurity and formed Under the active layer; a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer; and a first electrode pad electrically connected to the first electrode And a second electrode pad electrically connected to the second electrode, wherein the LED chip is electrically connectable to the substrate via the first electrode pad and the second electrode pad.

According to another aspect of the present invention, a backlight unit includes: a light guide plate; and a light source module disposed on at least one side of the light guide plate and emitting light, wherein the light source module comprises: a light emitting diode ( An LED) wafer electrically connected to the substrate via a lower surface thereof and including a light exit surface formed on one side surface thereof such that light of the LED wafer is emitted via the light exit surface; a wavelength conversion layer is formed And affixing at least the light exit surface of the LED wafer; and a reflector formed on a region of the LED chip except the light exit surface.

The light source module may further include an intervention in the substrate and the LED chip An underfill comprising a reflective material.

The underfill may comprise a phosphor material.

The LED wafer can be mounted on the substrate by flip chip bonding or surface mount technology (SMT).

According to another aspect of the present invention, a method of manufacturing a light source module includes: manufacturing a light emitting diode (LED) wafer including a light exit surface formed on one side surface thereof such that the LED Light of the wafer is emitted via the light exit surface; a wavelength conversion layer is formed on the LED wafer to enclose the light exit surface of at least the LED wafer; and the said light exit surface A reflector is formed on the area of the LED wafer.

Forming the reflector may include: forming the reflector on an upper surface and a side surface of the LED wafer; and when the reflector is formed on the light exit surface, by self-corresponding to the light The area of the exit face removes the reflector to expose the wavelength conversion layer.

Exposing the wavelength conversion layer can include removing the reflector from the region corresponding to the light exit face by high speed cutting.

The method can further include forming an underfill comprising a reflective material between the substrate and the LED wafer after forming the reflector.

Forming the underfill may include: forming a barrier disposed on the substrate to abut the light exit surface of the LED wafer; injecting the underfill into a region between the substrate and the LED wafer And removing the barrier after forming the underfill.

The method can further include electrically connecting the LED wafer to a substrate, wherein the LED wafer can be mounted on the substrate by flip chip bonding or surface mount technology (SMT).

Manufacturing the LED wafer may include: forming a first semiconductor layer doped with a first conductivity type impurity; forming an active layer under the first semiconductor layer; forming a second conductivity type impurity under the active layer a doped second semiconductor layer; forming a first electrode electrically connected to the first semiconductor layer; forming a second electrode electrically connected to the second semiconductor layer; forming a first electrode electrically connected to the first electrode a liner; and a second liner electrically connected to the second electrode.

According to an embodiment of the present invention, the LED chips are mounted side by side with the light guiding plate, thereby providing a side-emitting thin backlight unit.

Further, according to an embodiment of the present invention, a wavelength conversion layer is formed on a side surface of the LED wafer facing the light guide plate, and then formed on a region of the LED wafer other than the side surface of the LED wafer The reflector has a light exiting path toward the light guiding plate, thereby improving luminous efficiency of the LED wafer when the LED chip is mounted side by side with the light guiding plate.

Further, in accordance with an embodiment of the present invention, an underfill comprising a reflective material is formed between the LED wafer and the substrate to prevent light generated from the LED wafer from passing through the LED wafer other than the designated light exit surface. The surface emits and concentrates the light on the light exit surface, thereby improving the luminous efficiency.

Further, according to an embodiment of the present invention, the underfill is formed such that the reflective material is not applied to the light exit surface, thereby removing the obstacle from the light exit path and reducing The distance between the LED wafer and the light guide plate to improve luminous efficiency.

10‧‧‧LED package

23‧‧‧First semiconductor layer

25‧‧‧ active layer

27‧‧‧Second semiconductor layer

28‧‧‧reflective layer

29‧‧‧Barrier layer

30‧‧‧Reflective electrode

31‧‧‧Under insulation

33‧‧‧current distribution layer

35‧‧‧Upper insulation

37a‧‧‧First electrode pad

37b‧‧‧Second electrode pad

100‧‧‧Light source module

110‧‧‧LED chip

111‧‧‧Substrate

113‧‧‧Semiconductor stacking

120‧‧‧wavelength conversion layer

130‧‧‧ reflector

140‧‧‧Substrate

141a‧‧‧Substrate liner

141b‧‧‧Substrate liner

150a‧‧‧bump

150b‧‧‧bump

170‧‧‧ barrier

200‧‧‧ bottom filler

230‧‧‧ optical sheets

240‧‧‧Frame

250‧‧‧Light guide

260‧‧‧Reflective flakes

270‧‧‧Under the cover

280‧‧‧ top cover

BLU‧‧‧Backlight unit

DP‧‧‧ display panel

EA‧‧‧ light exit surface

FS‧‧‧Color Filter Substrate

M‧‧‧ countertop

SS‧‧‧thin film transistor substrate

The above and other aspects, features, and advantages of the present invention will become apparent from the Detailed Description of the Drawing.

1 is a cross-sectional view of a prior art light emitting diode package and a backlight unit including the light emitting diode package.

2 through 5 are cross-sectional views of a light source module in accordance with an embodiment of the present invention.

Fig. 6(a) is a plan view of the LED chip shown in Figs. 2 to 5.

Fig. 6(b) is a cross-sectional view of the LED wafer taken along line II' shown in Fig. 6(a).

Figure 7 is an exploded perspective view of a display element including a backlight unit, in accordance with one embodiment of the present invention.

Figure 8 is a cross-sectional view of the display element taken along line II-II' shown in Figure 7.

9 through 11 show a manufacturing procedure of a light source module in accordance with one embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are provided by way of example in order to fully convey the spirit of the invention to those skilled in the art. Therefore, the invention is not limited to the embodiments disclosed herein and may be embodied in various forms. In addition, the shape of the components can be exaggerated in the drawings. Throughout the specification, like reference numerals indicate classes that have the same or similar functions. Like a component. The modifications of the components within the spirit and scope of the present invention are not intended to be limiting, and are provided for the purpose of clarity of the present invention and may be limited only by the scope of the accompanying claims.

Hereinafter, the embodiments of the present invention will be specifically described with reference to the drawings, so that the present invention can be easily carried out by those skilled in the art.

2 through 5 are cross-sectional views of a light source module in accordance with an exemplary embodiment of the present invention. Referring to FIGS. 2 through 5, a light source module 100 according to an exemplary embodiment of the present invention includes a light emitting diode (LED) wafer 110, a wavelength conversion layer 120, and a reflector 130.

The LED wafer 110 includes a growth substrate 111 and a semiconductor stack 113. The LED wafer 110 can be electrically connected to the substrate 140 by direct flip-chip bonding or surface mount technology (SMT). The electrode pads 37a, 37b exposed on the lower surface of the LED wafer 110 are electrically connected to the substrate pads 141a, 141b via the bumps 150a, 150b, respectively. Because the light source module 100 does not use wires, no module assembly is needed to protect the wires, and portions of the wavelength conversion layer 120 need not be removed to expose the bond pads. Therefore, the flip chip type LED wafer 110 exhibits less color deviation and brightness unevenness than the LED wafer using the bonding wires. This also makes it possible to simplify the module manufacturing process.

The wavelength conversion layer 120 covers the LED wafer 110. The LED wafer 110 includes a side surface through which light is emitted, that is, a light exit surface EA. The wavelength conversion layer 120 may enclose at least the light exit surface EA and may also close the upper surface and the side surface of the LED wafer 110. That is, the wavelength conversion layer may be formed only on the light exit surface EA of the LED wafer 110. Upper, or the light exit surface EA of the LED wafer 110, the upper surface, and some side surfaces. Alternatively, a wavelength conversion layer may be formed on the upper surface of the LED wafer 110 and on all side surfaces (including the light exit surface EA). Further, the wavelength conversion layer 120 may be formed of a fluorescent material capable of converting the wavelength of light emitted from the LED wafer 110. The wavelength conversion layer 120 may be coated onto the LED wafer 110 to a predetermined thickness to cover the upper surface and the side surface of the LED wafer 110. When the wavelength conversion layer 120 covers the upper surface and the side surface of the LED wafer, the thickness of the region covering the upper surface may be the same as or different from the thickness of the region covering the side surface. Further, the region covering the light exit surface EA may have a thickness different from the thickness of the region covering the upper surface and the side surface other than the light exit surface EA.

The reflector 130 is formed on a region of the LED wafer 110 other than the light exit surface EA. At this time, the reflector 130 may be formed directly on the LED wafer 110 or on another component interposed therebetween. That is, according to various embodiments, the reflector 130 may be formed directly on the LED wafer 110 as shown in FIG. 2 or formed on the wavelength conversion layer 120 formed on the LED wafer 110 as shown in FIGS. 3 and 4.

The reflector 130 is for reflecting light toward the light exit surface EA. That is, the reflector formed on the area of the LED wafer 110 other than the light exit surface EA is used to guide light toward the light exit surface EA to emit light via the light exit surface EA.

The substrate 140 includes substrate pads 141a, 141b that are electrically connected to the LED wafer 110. The bumps 150a, 150b are respectively disposed on the substrate pads 141a, 141b. Although not particularly limited, the substrate 140 may be, for example, a metal printed circuit board (PCB) that facilitates heat dissipation. The substrate 140 may be a rod type substrate having a long axis and a short axis.

The underfill 200 is interposed between the LED wafer 110 and the substrate 140. The underfill 200 is used to reflect light generated from the LED wafer 110, thereby improving luminous efficiency. Further, the underfill 200 serves to prevent moisture infiltration between the LED wafer 110 and the substrate 140. The underfill 200 comprises a reflective material. For example, the underfill 200 can comprise a resin as well as a reflective material within the resin. The reflective material may comprise a material selected from the group consisting of TiO ₂ , SiO ₂ , ZrO ₂ , PbCO ₃ , PbO, Al ₂ O ₃ , ZnO, Sb ₂ O _{3 ,} and combinations thereof. The underfill 200 is formed up to an area aligned with one surface of the LED wafer 110 defined as the light exit surface EA. Although not particularly limited, the underfill 200 may be formed by dosing. The underfill 200 may further comprise a fluorescent material (not shown). The underfill 200 can have a predetermined adhesive strength.

Therefore, the light source module 100 can concentrate the light on its side surface (light exit surface EA) using the reflector 130 and the underfill 200 while minimizing optical loss, thereby maximizing luminous efficiency.

In addition, the LED chip 110 is electrically connected to the substrate 140 by direct flip-chip bonding or SMT, whereby the light source module 100 can achieve high efficiency and compactness compared to a typical light source module of a package type using a wire. The light source module 100 can be made thinner than a typical package type light source module mounted on a side surface of the light guide plate.

The structure of the LED wafer 110 will be described in more detail with reference to FIGS. 6(a) and 6(b). 6(a) is a plan view of the LED wafer shown in FIG. 5, and FIG. 6(b) is a cross-sectional view of the LED wafer taken along line II' shown in FIG. 6(a). Referring to FIGS. 6(a) and 6(b), a light emitting diode (LED) wafer according to the present invention may include a growth substrate 111 and a semiconductor stack 113.

The semiconductor stack 113 includes a first semiconductor layer 23 formed on the growth substrate 111 and doped with impurities of a first conductivity type, and a mesa M separated from each other on the first semiconductor layer 23. Each of the mesas M includes: an active layer 25; and a second semiconductor layer 27 doped with a second conductivity type impurity. The active layer 25 is interposed between the first semiconductor layer 23 and the second semiconductor layer 27. The reflective electrodes 30 are respectively disposed on the mesa M.

The mesas M may have an elongated shape and extend parallel to each other in one direction as shown. This shape makes it simple to form the mesa M of the same shape on the wafer area of the growth substrate 111.

Although the reflective electrode 30 may be formed on the respective mesas M after the mesa M is formed, the present invention is not limited thereto. Alternatively, the reflective electrode 30 may be previously formed on the second semiconductor layer 27 before the formation of the mesa M and after the growth of the second semiconductor layer 27. The reflective electrode 30 covers all of the upper surfaces of the mesa M and has substantially the same shape as the plane of the mesa M.

The reflective electrode 30 includes a reflective layer 28 and may further include a barrier layer 29. The barrier layer 29 may cover the upper surface and the side surface of the reflective layer 28. For example, by forming a pattern of the reflective layer 28 and then forming a barrier layer 29 on the pattern, the barrier layer 29 may be formed to cover the upper surface and the side surface of the reflective layer 28. For example, the reflective layer 28 can be formed by depositing Ag, Ag alloy, Ni/Ag, NiZn/Ag, or TiO/Ag followed by patterning. The barrier layer 29 may be formed of Ni, Cr, Ti, Pt, Rd, Ru, W, Mo, TiW or a composite layer thereof, and prevents diffusion or contamination of the metal material in the reflective layer.

After the mesa M is formed, the edges of the first semiconductor layer 23 may also be subjected to etching. Therefore, the upper surface of the substrate 21 can be exposed. A side surface of the first semiconductor layer 23 may also be formed.

The LED wafer according to the present invention further includes a lower insulating layer 31 to cover the mesas M and the first semiconductor layer 23. The lower insulating layer 31 has an opening in a specific region thereof to allow electrical connection to the first semiconductor layer 23 and the second semiconductor layer 27. For example, the lower insulating layer 31 may have an opening exposing the first semiconductor layer 23 and an opening exposing the reflective electrode 30.

The openings may be disposed between the mesas M and near the edges of the substrate 21, and may have an elongated shape extending along the mesas M. Further, the opening may be restrictively disposed on the mesa M to be biased toward the same end of the mesa.

The LED wafer according to the present invention further includes a current spreading layer 33 formed on the lower insulating layer 31. The current spreading layer 33 covers the mesas M and the first semiconductor layer 23. The current spreading layer 33 has openings disposed above the respective mesas M such that the reflective electrodes are exposed through the openings. The current spreading layer 33 may form an ohmic contact with the first semiconductor layer 23 via the opening of the lower insulating layer 31. The current spreading layer 33 is electrically insulated from the mesa M and the reflective electrode 30 by the lower insulating layer 31.

The opening of the current spreading layer 33 has an area larger than the area of the lower insulating layer 31 in order to prevent the current spreading layer 33 from contacting the reflective electrode 30.

The current spreading layer 33 is formed over substantially the entire upper region of the substrate 31 outside its opening. Therefore, the current can be easily dispersed through the current spreading layer 33. The current spreading layer 33 may comprise a highly reflective metal layer, such as an Al layer, and is highly reflective. The metal layer may be formed on a bonding layer such as a Ti, Cr, Ni layer or the like. Further, a protective layer having a single layer or a composite layer structure of Ni, Cr or Au may be formed on the highly reflective metal layer. The current spreading layer 33 may have a multilayer structure of, for example, Ti/Al/Ti/Ni/Au.

The LED wafer further includes an upper insulating layer 35 formed on the current spreading layer 33. The upper insulating layer 35 has an opening exposing the current spreading layer 33 and an opening exposing the reflective electrode 30. The upper insulating layer 35 may use an oxide insulating layer, a nitride insulating layer, a mixed layer of such insulating layers or alternately stacked, or a polymer such as polyimine, Teflon, parylene or the like. ) formed.

The first electrode pad 37a and the second electrode pad 37b are formed on the upper insulating layer 35. The first electrode pad 37a is connected to the current spreading layer 33 via the opening of the upper insulating layer 35, and the second electrode pad 37b is connected to the reflective electrode 30 via the opening of the upper insulating layer 35. The first electrode pad 37a and the second electrode pad 37b may be used as a pad for connecting the bumps of the LED chip on the circuit board or a pad for the SMT.

The first electrode pad 37a and the second electrode pad 37b may be simultaneously formed by the same process (for example, by photolithography and etching, or by a lift-off technique). The first electrode pad 37a and the second electrode pad 37b may include a bonding layer formed of, for example, Ti, Cr, Ni, or the like, and a highly conductive metal layer formed of Ag, Au, and the like. The first electrode pad 37a and the second electrode pad 37b may be formed such that their ends are disposed on the same plane, and the LED chips may thus be bonded to the conductive patterns formed at the same height on the substrate by flip chip bonding .

The LED wafer is completely fabricated by dividing the growth substrate 111 into individual LED wafer units. The growth substrate 111 can also be removed from the LED wafer before or after being divided into individual LED wafer units.

Therefore, the LED wafer according to the present invention directly bonded to the substrate by flip chip bonding has an advantage of achieving high efficiency and compactness as compared with a typical light-emitting element of a package type.

7 is an exploded perspective view of a display element including a backlight unit, and FIG. 8 is a cross-sectional view of the display element taken along line II-II' shown in FIG. 7, in accordance with an embodiment of the present invention.

Referring to FIG. 7 and FIG. 8 , the display element includes: a display panel DP for displaying an image; a backlight unit BLU disposed at a rear side of the display panel DP and emitting light; and a frame 240 supporting the display panel DP and accommodating the backlight unit BLU; And a top cover 280 surrounding the display panel DP.

The display panel DP includes a color filter substrate FS and a thin film transistor (TFT) substrate SS which are assembled to face each other while maintaining a uniform cell gap. The display panel DP may further include a liquid crystal layer between the color filter substrate FS and the thin film transistor substrate SS depending on the type thereof.

Although not shown in detail, the thin film transistor substrate SS includes gate lines and data lines that cross each other to define pixels therebetween, and each of the intersection regions disposed therebetween and in a one-to-one correspondence A thin film transistor connected to the pixel electrode mounted in each of the pixels. The color filter substrate FS includes R, G, and B color filters corresponding to respective pixels, disposed along the periphery of the substrate and shielded The black matrix of the gate line, the data line, and the thin film transistor, and the common electrode covering all of these components. Here, the common electrode may be formed on the thin film transistor substrate SS.

The backlight unit BLU supplies light to the display panel DP, and includes: a lower cover 270 partially open at an upper side thereof; a light source module 100 disposed on one side in the lower cover 270; and a light guide plate 250 parallel to the light source module 100 is placed to convert the point light into surface light. In the prior art, the light source module 100 is generally disposed on the inner side surface of the lower cover 270. In this case, there is a limitation in reducing the height of the backlight unit or the display panel including the backlight unit due to the width of the light source module 100. According to the present invention, the light source module 100 is disposed on the bottom surface in the lower cover 270, whereby the backlight unit or the display panel including the backlight unit is made thinner than the backlight unit of the prior art or the display panel including the backlight unit. According to the description, the light source module 100 disposed on the bottom surface in the lower cover 270 can be illustrated as being disposed parallel to the light guide plate 250.

In addition, the backlight unit BLU according to the present invention further includes: an optical sheet 230 disposed on the light guiding plate 250 to diffuse and collect light; and a reflective sheet 260 disposed under the light guiding plate 250 to be reflected toward the display panel DP toward the light guiding plate The light traveling in the lower part of 250.

In this document, a detailed description of the light source module 100 will not be omitted. See Figure 5 for details.

The light source module 100 is fabricated by directly mounting an LED wafer on a substrate by flip chip bonding or SMT, and then forming an underfill containing a reflective material between the substrate and the LED wafer. Therefore, the light source module 100 facilitates the slimness of the backlight unit, and can concentrate the light on the light source module 100 by using the reflector and the underfill. On one side, the luminous efficiency is maximized while minimizing light loss.

9 through 11 show a manufacturing procedure of a light source module in accordance with an exemplary embodiment of the present invention. Referring to Figures 9 through 11, the manufacturing process of the light source module includes manufacturing an LED wafer. In this operation, the LED wafer 110 is first fabricated.

The LED wafer 110 can be fabricated by forming the semiconductor stack 113 on the growth substrate 111. The LED 110 may be formed with electrode pads 37a, 37b on a lower portion thereof. The features of the light source module are the same as those of the light source module shown in FIGS. 2 to 5. Therefore, similar features are denoted by like reference numerals and will be briefly described with respect to the manufacturing process, without a detailed description of the features.

The fabrication of the LED wafer includes forming a first semiconductor layer doped with a first conductivity type impurity, forming an active layer under the first semiconductor layer, and forming a second semiconductor layer doped with a second conductivity type impurity under the active layer . Thereafter, a first electrode is formed to be electrically connected to the first semiconductor layer, a second electrode is formed to be electrically connected to the second semiconductor, and a first pad and a second pad are formed to be electrically connected to the first electrode and the second electrode, respectively .

Next, in the operation of forming the wavelength conversion layer, the wavelength conversion layer 120 is formed to block at least the light exit surface of the LED wafer. Next, in the operation of forming the reflector 130, the reflector 130 is formed on the area of the LED wafer other than the light exit surface.

According to various embodiments, the reflector 130 may be formed directly on the LED wafer or another component formed on the LED wafer, such as the wavelength conversion layer 120. When the reflector is formed on the light exit surface, the wavelength conversion layer is exposed by removing the reflector from a region corresponding to the light exit surface.

The exposed wavelength conversion layer 120 corresponds to the light exit surface EA of the LED wafer 110. Although not particularly limited, high speed cutting can be used to remove the reflector 130.

The manufacturing process of the light source module according to an embodiment of the present invention further includes electrically connecting the LED chip to the substrate. In this operation, the electrode pads 37a, 37b of the LED wafer 110 are respectively connected to the substrate pads 141a, 141b of the substrate 140. At this time, the LED wafer 110 can be directly electrically connected to the substrate 140 by flip chip bonding or surface mount technology (SMT). Here, the bumps 150a, 150b are interposed between the substrate pads 141a, 141b and the electrode pads 37a, 37b, respectively.

According to an embodiment of the present invention, the operations of forming the wavelength conversion layer and the reflector and the operation of electrically connecting the LED wafer to the substrate may be performed in different orders. That is, the LED wafer can be electrically connected to the substrate before or after the wavelength conversion layer and the reflector are formed on the LED wafer.

The manufacturing process of the light source module further includes forming an underfill 200 between the substrate 140 and the LED wafer 110. Specifically, the barrier 170 is formed on the surface corresponding to the light exit surface EA of the LED wafer 110. The barrier 170 contacts the light exit surface EA of the LED wafer 110. The barrier 170 is disposed adjacent to the substrate 140. The barrier 170 may be formed on the substrate 140 by a frame structure including a photoresist or an adhesive. After the barrier 170 is formed, the underfill is implanted into the region between the substrate and the LED wafer. In this case, the barrier 170 serves to limit the area where the underfill 200 will be formed. In particular, the barrier 170 prevents the underfill 200 from extending to the light exit surface EA. The barrier 170 can be removed by etching or other physical methods after the underfill 200 is formed.

The underfill 200 serves to reflect light generated from the LED wafer 110, thereby improving luminous efficiency and preventing infiltration of moisture. The underfill 200 comprises a reflective material. For example, the underfill 200 may comprise a resin and a reflective material within the resin, and the reflective material may comprise a material selected from the group consisting of TiO ₂ , SiO ₂ , ZrO ₂ , PbCO ₃ , PbO , Al ₂ O ₃ , ZnO, Sb ₂ O ₃ and combinations thereof. The barrier 170 allows the underfill 200 to be formed up to the area aligned with the light exit surface EA. Although not particularly limited, the underfill 200 may be formed by dosing. The underfill 200 may further comprise a fluorescent material (not shown). The underfill 200 can have a predetermined adhesive strength.

As described above, the light source module according to the embodiment of the present invention can use the reflector 130 and the underfill 200 to concentrate light on one side thereof while minimizing light loss, thereby maximizing luminous efficiency.

In addition, the light source module according to the present invention in which the LED chip 110 is electrically connected to the substrate 140 by direct flip-chip bonding or SMT can achieve high efficiency and compactness compared to a typical light source module of a package type using a wire.

Although various embodiments of the invention have been described, the invention is not limited to the specific embodiments. In addition, the components described in the specific embodiments may be applied to other embodiments in the same or similar manner without departing from the spirit and scope of the invention.

37a‧‧‧First electrode pad

37b‧‧‧Second electrode pad

100‧‧‧Light source module

110‧‧‧LED chip

111‧‧‧Substrate

113‧‧‧Semiconductor stacking

120‧‧‧wavelength conversion layer

130‧‧‧ reflector

140‧‧‧Substrate

141a‧‧‧Substrate liner

141b‧‧‧Substrate liner

150a‧‧‧bump

150b‧‧‧bump

200‧‧‧ bottom filler

Claims (17)

A light source module comprising: a light emitting diode (LED) wafer electrically connected to a substrate via a lower surface thereof, and comprising a laterally disposed light exit surface, wherein light of the LED wafer is emitted via the light exit surface a wavelength conversion layer disposed on the LED wafer and covering at least the light exit surface; and a reflector disposed on the LED wafer and exposing the light exit surface. The light source module of claim 1, further comprising an underfill interposed between the substrate and the LED wafer and comprising a reflective material. The light source module of claim 2, wherein the reflective material comprises a material selected from the group consisting of TiO ₂ , SiO ₂ , ZrO ₂ , PbCO ₃ , PbO, Al ₂ O ₃ , ZnO, Sb ₂ O ₃ and combinations thereof. The light source module of claim 2, wherein the underfill comprises a fluorescent material. The light source module of claim 1, wherein the LED chip is mounted on the substrate by flip chip bonding or surface mount technology (SMT). The light source module of claim 1, wherein the LED chip comprises: a first semiconductor layer doped with a first conductivity type impurity; an active layer formed under the first semiconductor layer; a second semiconductor layer doped with a second conductivity type impurity and formed on the active a layer; a first electrode electrically connected to the first semiconductor layer; a second electrode electrically connected to the second semiconductor layer; a first electrode pad electrically connected to the first electrode; and a second An electrode pad electrically connected to the second electrode, wherein the LED chip is electrically connected to the substrate via the first electrode pad and the second electrode pad. A backlight unit includes: a light guide plate; and a light source module disposed on at least one side of the light guide plate and configured to emit light, wherein the light source module comprises: a light emitting diode (LED) chip, via a lower surface thereof electrically connected to the substrate, and comprising a laterally disposed light exit surface, wherein light of the LED wafer is emitted via the light exit surface; a wavelength conversion layer disposed on the LED wafer and covering at least the a light exit surface; and a reflector disposed on the LED wafer and exposing the light exit surface. The backlight unit of claim 7, wherein the light source module further comprises an underfill interposed between the substrate and the LED wafer and comprising a reflective material. The backlight unit of claim 8, wherein the underfill Materials include fluorescent materials. The backlight unit of claim 7, wherein the LED chip is mounted on the substrate by flip chip bonding or surface mount technology (SMT). A method of fabricating a light source module, comprising: fabricating a light emitting diode (LED) wafer, the LED chip including a light exit surface, wherein light of the LED wafer is emitted via the light exit surface; Forming a wavelength conversion layer thereon to cover at least the light exit surface of the LED wafer; and forming a reflector on the LED wafer that exposes the light exit surface. The method of manufacturing a light source module according to claim 11, wherein the forming the reflector comprises: forming the reflector on an upper surface and a side surface of the LED wafer; and if the reflector is formed On the light exit surface, the wavelength conversion layer is exposed by removing the reflector from a region corresponding to the light exit surface. The method of manufacturing a light source module of claim 12, wherein exposing the wavelength conversion layer comprises cutting the reflector to expose the light exit surface. The method of manufacturing a light source module according to claim 11, further comprising forming an underfill comprising a reflective material between the substrate and the LED wafer after forming the reflector. A method of manufacturing a light source module according to claim 14, wherein Forming the underfill in the middle layer includes: forming a barrier disposed on the substrate to abut the light exit surface of the LED wafer; injecting the underfill into a region between the substrate and the LED wafer And removing the barrier after forming the underfill. The method of manufacturing a light source module according to claim 11, further comprising electrically connecting the LED chip to a substrate, wherein the LED chip is mounted on the substrate by flip chip bonding or surface mount technology (SMT) On the substrate. The method of manufacturing a light source module according to claim 11, wherein the manufacturing the LED chip comprises: forming a first semiconductor layer doped with a first conductivity type impurity; forming under the first semiconductor layer An active layer; forming a second semiconductor layer doped with a second conductivity type impurity under the active layer; forming a first electrode electrically connected to the first semiconductor layer; forming an electrical connection to the second semiconductor layer a second electrode; forming a first pad electrically connected to the first electrode; and forming a second pad electrically connected to the second electrode.