WO2014035087A1

WO2014035087A1 - Light-emitting module for surface lighting

Info

Publication number: WO2014035087A1
Application number: PCT/KR2013/007413
Authority: WO
Inventors: 김은주; 정승호; 송영준; 김다혜
Original assignee: 서울반도체 주식회사
Priority date: 2012-08-31
Filing date: 2013-08-16
Publication date: 2014-03-06
Also published as: KR102001665B1; KR20140029911A

Abstract

A light-emitting module for surface lighting is disclosed. The light-emitting module comprises: a circuit board; a light-emitting element which is flip-bonded to the circuit board; and a lens which is coupled to the circuit board and disperses light emitted from the light-emitting element. In addition, the light-emitting element comprises a flip-chip type light-emitting diode chip and a wavelength conversion layer coated on the light-emitting diode chip. The light-emitting module can be made to be slim by mounting the flip-chip type light-emitting diode chip on the circuit board.

Description

Light Emitting Module for Surface Lighting

The present invention relates to a light emitting module, and more particularly to a light emitting module for a surface illumination having a lens.

BACKGROUND OF THE INVENTION A light emitting module for a surface illumination used in a light emitting module or a surface lighting apparatus for backlighting a liquid crystal display generally includes a lens for mounting a light emitting element on a circuit board and dispersing light emitted from the light emitting element at a wide angle. By uniformly dispersing the light emitted from the light emitting device by using the lens, a large area can be uniformly irradiated with a small number of light emitting devices.

1 is a schematic cross-sectional view for describing a light emitting module according to the prior art.

Referring to FIG. 1, the light emitting module includes a circuit board 100, a light emitting device 200, and a lens 300. The circuit board 100 is a printed circuit board on which a conductive pattern (not shown) is formed.

The light emitting device 200 includes a main body 250 having a recess, a light emitting diode chip 210 mounted in the recess, and a molding part 230 covering the light emitting diode chip 210 in the recess. The molding part 230 includes a phosphor for wavelength converting light emitted from the light emitting diode chip 210. The light emitting device 200 is electrically connected to a conductive pattern (not shown) of the circuit board 100.

Meanwhile, the lens 300 has legs 310, and the legs 310 are attached to the circuit board 100 and disposed on the light emitting device 200. The lens 300 has an entrance surface 330 through which light is incident from the light emitting device 200 and an exit surface 350 through which the incident light is emitted. The incident surface 330 is provided in the form of a recess in the lower portion of the lens 300.

The light emitting module according to the related art may implement uniform light over a large area by dispersing the light emitted from the light emitting device 200 through the lens 300. However, since the light emitting device 200 disposed on the circuit board 100 and the lens 300 mounted on the circuit board 100 through the legs 310 have a limitation in slimming of the light emitting module. Furthermore, since the main body 250 having the recess is adopted, the size of the light emitting device 200 is relatively large, and thus the size of the lens 300 is relatively increased. Moreover, there is a limit in dispersing light through the lens 300 because the directivity angle of the light emitted through the main body 250 is relatively narrow.

Furthermore, in order to realize a uniform surface light source, the light emitting diode chip 210, the light emitting device 200, and the lens 300 in the light emitting device 200 need to be precisely aligned. However, the light emitting module according to the prior art has a limitation in reducing alignment tolerance because all of the light emitting diode chip 210, the light emitting device 200, and the lens 300 must be precisely positioned.

The problem to be solved by the present invention is to provide a light emitting module that can reduce the overall height.

Another object of the present invention is to provide a light emitting module that can reduce alignment tolerances.

Another object of the present invention is to provide a light emitting module capable of providing uniform light over a large area by adopting a light emitting diode suitable for a surface light source.

A light emitting module according to embodiments of the present invention includes a circuit board; A light emitting device flip-bonded to the circuit board; And a lens coupled to the circuit board and dispersing light emitted from the light emitting element. On the other hand, the light emitting device is a flip chip light emitting diode chip; And a wavelength conversion layer coated on the light emitting diode chip. By mounting a flip chip type light emitting diode chip on a circuit board, the light emitting module can be made slim.

The wavelength conversion layer may cover the top and side surfaces of the light emitting diode chip. In a particular embodiment, the wavelength conversion layer may cover only the top surface of the LED chip.

The lens is coupled to the circuit board without employing conventional legs. Accordingly, the lower surface of the lens is closer to the upper surface of the circuit board, and the light emitting module is further slimmer.

For example, the circuit board may have a protrusion on an upper surface thereof, and the lens may have a receiving groove accommodating the protrusion, and the lens may be coupled to the circuit board by receiving the protrusion. Alternatively, a dam portion may be formed on the circuit board instead of the protrusion, and the lens may be coupled to the circuit board by receiving the dam portion. The dam portion may be formed of a silicone resin or an optical sheet.

In another embodiment, the light emitting module may further include an optical sheet attached to the circuit board and having an opening for exposing the light emitting device. The lens may be inserted into an opening of the optical sheet and coupled to the circuit board.

In another embodiment, the circuit board may include a recess, and the lens may be fitted into the recess and coupled to the circuit board.

The lens has an incident surface on which light emitted from the light emitting element is incident and an exit surface on which incident light is emitted. The incident surface may be an inner surface of a recess located on the lower surface of the lens. Furthermore, the recess may include a first recess and a second recess positioned at an inlet side of the first recess and surrounding the first recess.

In example embodiments, the light emitting diode chip may include a first conductivity type semiconductor layer; A plurality of mesas spaced apart from each other on the first conductive semiconductor layer, each of the mesas including an active layer and a second conductive semiconductor layer; Reflective electrodes positioned on the plurality of mesas, respectively, for ohmic contact with a second conductivity-type semiconductor layer; And openings covering the plurality of mesas and the first conductivity type semiconductor layer, the openings being located in the upper region of each mesa and exposing the reflective electrodes, ohmic contacting the first conductivity type semiconductor layer, and the plurality of mesas. And a current spreading layer insulated from the light emitting diode chip, the light emitting diode chip being flip bonded to the circuit board.

Since the current spreading layer covers the plurality of mesas and the first conductivity type semiconductor layer, the current spreading performance is improved through the current spreading layer.

The first conductivity type semiconductor layer is continuous. In addition, the plurality of mesas may have an elongated shape extending in parallel to each other in one direction, and the openings of the current spreading layer may be located at the same end side of the plurality of mesas. Therefore, a pad connecting the reflective electrodes exposed to the openings of the current spreading layer can be easily formed.

The current spreading layer may include a reflective metal such as Al. Accordingly, in addition to the light reflection by the reflective electrodes, the light reflection by the current spreading layer can be obtained, and thus, the light traveling through the plurality of mesas sidewalls and the first conductivity type semiconductor layer can be reflected.

The reflective electrodes may each include a reflective metal layer and a barrier metal layer. Further, the barrier metal layer may cover the top and side surfaces of the reflective metal layer. As a result, the reflective metal layer can be prevented from being exposed to the outside, and deterioration of the reflective metal layer can be prevented.

The light emitting diode chip may include: an upper insulating layer covering at least a portion of the current spreading layer and having openings exposing the reflective electrodes; And a second pad disposed on the upper insulating layer and connected to the reflective electrodes exposed through the openings of the upper insulating layer, and further comprising a first pad connected to the current spreading layer. Can be. The first pad and the second pad may be formed in the same shape and size, and thus flip chip bonding may be easily performed.

The light emitting diode chip may further include a lower insulating layer positioned between the plurality of mesas and the current spreading layer to insulate the current spreading layer from the plurality of mesas. The lower insulating layer may have openings positioned in the upper mesas and exposing the reflective electrodes.

Further, each of the openings of the current spreading layer may have a wider width than the openings of the lower insulating layer so that all of the openings of the lower insulating layer are exposed. That is, sidewalls of the openings of the current spreading layer are located on the lower insulating layer. In addition, the LED chip may further include an upper insulating layer covering at least a portion of the current spreading layer and having openings exposing the reflective electrodes. The upper insulating layer may cover sidewalls of the openings of the current spreading layer.

The lower insulating layer may be a reflective dielectric layer, such as a distributed Bragg reflector (DBR).

The LED chip may further include a growth substrate, and the growth substrate may be, for example, a sapphire substrate or a gallium nitride substrate. The wavelength conversion layer covers the growth substrate to convert wavelengths of light emitted from the growth substrate to the outside.

According to the embodiments of the present invention, the light emitting module can be made slim, and furthermore, the mounting tolerance of the light emitting module can be reduced by mounting the light emitting diode chip directly on the circuit board. Furthermore, the illumination intensity distribution can be improved by adopting a flip chip type light emitting diode chip having a relatively wide beam angle.

1 is a cross-sectional view illustrating a light emitting module according to the prior art.

2 is a cross-sectional view illustrating a light emitting module according to an embodiment of the present invention.

3 is a cross-sectional view for describing a light emitting module according to another embodiment of the present invention.

4 to 7 are cross-sectional views illustrating various light emitting modules according to embodiments of the present invention.

8 to 12 are views for explaining a method of manufacturing a light emitting diode chip according to an embodiment of the present invention, in each of the drawings (a) is a plan view and (b) is a cross-sectional view taken along the cutting line A-A.

It is a top view for demonstrating the modified example of a mesa structure.

Figure 14 is a graph showing the directivity distribution of the conventional LED package 200 and the flip chip LED chip having a conformal coating layer of the present application (a) and (b), respectively.

FIG. 15 is a graph illustrating directions of distribution of light emitting modules using a conventional LED package 200 and light emitting modules using a flip chip type LED chip having a conformal coating layer of the present application as (a) and (b), respectively.

Figure 16 shows the illuminance distribution of the light emitting module combining 16 LED array and the lens (a) is a conventional LED package having a 120-degree directivity (b) is a flip-chip type light emitting diode to which the conformal coating layer according to the present application is applied The illuminance distribution of the light emitting module to which the chip is applied is shown.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; The following embodiments are provided as examples to ensure that the spirit of the present invention can be fully conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, widths, lengths, thicknesses, and the like of components may be exaggerated for convenience. Like numbers refer to like elements throughout.

Referring to FIG. 2, the light emitting module includes a circuit board 100a, a dam unit 130, a light emitting diode chip 220, a conformal coated wavelength conversion layer 240, and a lens 300a. The circuit board 100a is a printed circuit board on which a printed circuit (not shown) is formed.

The dam 130 is formed around the mounting area of the LED chip 220. The dam unit 130 may be formed by attaching the optical sheet to the circuit board 100a in a ring shape, or may be formed using a silicone resin.

The light emitting diode chip 220 is mounted on the circuit board 100a. The LED chip 220 is flip-bonded without using a bonding wire and connected to the printed circuit on the direct circuit board 100a. Since the present invention does not use a wire when bonding the LED chip 220 on the circuit board 100a, the molding part for protecting the wire is not required, and the wavelength conversion layer 240 is used to expose the bonding pad. You don't even have to remove a part of). Therefore, by adopting the flip type light emitting diode chip 220, color deviation and luminance unevenness may be eliminated and the module manufacturing process may be simplified as compared with using the light emitting diode chip using the bonding wire.

The light emitting diode chip 220 is a flip chip semiconductor chip formed of a gallium nitride-based compound semiconductor and may emit ultraviolet light or blue light. A flip chip type semiconductor according to an embodiment of the present invention will be described in detail later with reference to FIGS. 8 to 13.

Meanwhile, the wavelength conversion layer 240 covers the light emitting diode chip 220. As shown, the conformal coated wavelength conversion layer 240, for example, a phosphor layer, may be formed on the light emitting diode chip 220, and may convert the light emitted from the light emitting diode chip 220 to wavelength convert. The wavelength conversion layer 240 is coated on the LED chip 220 and may cover the top and side surfaces of the LED chip 220. In a particular embodiment, the wavelength conversion layer 240 may cover only the top surface of the LED chip 220. The light emitted from the light emitting diode chip 220 and the wavelength conversion layer 240 may be used to implement light of various colors, and in particular, may implement mixed light such as white light.

In the present exemplary embodiment, the conformal coated wavelength conversion layer 240 may be previously formed on the LED chip 220 and mounted on the circuit board 100a together with the LED chip 220.

On the other hand, the lens 300a has an entrance surface 330 through which light is incident from the LED chip 220 and an exit surface 350 through which light is emitted from the lens 300a to the outside. As illustrated, the incident surface 330 may be an inner surface of a bell shaped recess. The lens 300a disperses the light incident from the light emitting diode chip 220 by using the refraction of the light at the entrance surface 330 and the refraction of the light at the exit surface 350.

The lens 300a also has an accommodating groove for accommodating the dam 130, and by accommodating the dam 130, the lens 300a may be coupled to the circuit board 100a. Since the lens 300a can be coupled to the circuit board 100a by using the dam 130 and the receiving groove of the lens 300a, the conventional leg portion 310 of FIG. 1 can be removed. Accordingly, the lower surface of the lens 300a is close to the upper surface of the circuit board 100a, and thus, the light emitting module may be further slimmed.

Referring to FIG. 3, the light emitting module according to the present embodiment is generally similar to the light emitting module described with reference to FIG. 2, but there is a difference in the shape of the concave portion of the lens 300b.

That is, the incident surface of the lens 300b according to the present exemplary embodiment includes a longitudinally shaped first recessed inner surface 331 and an inner surface 333 of the second recessed portion surrounding the first recessed portion. The second recess is formed at the inlet side of the first recess and has a relatively wider width than the first recess.

The inner surface 333 of the second concave portion changes the traveling path of the light incident from the light emitting diode chip 220 to the upper side to prevent the light from being absorbed and lost by the dam unit 130.

4 is a cross-sectional view for describing a light emitting module according to another embodiment of the present invention.

Referring to FIG. 4, the light emitting module according to the present embodiment is generally similar to the light emitting module described with reference to FIG. 2, except that the circuit board 100b has the protrusion 150. That is, in the light emitting module of FIG. 2, the dam part 110 is formed to couple the lens 300a to the circuit board 100a. However, in the present exemplary embodiment, the protrusion 150 is provided on the circuit board 100b to provide the lens 300a. ) Are being combined.

According to the present exemplary embodiment, the process of forming the dam unit 110 may be omitted by forming the protrusion 150 on the circuit board 100b instead of the dam unit 110, and the lens 300a may be more stably provided. Can be bound to

Meanwhile, as described with reference to FIG. 3, the second concave portion may be formed at the entrance of the first concave portion to prevent light loss caused by the protrusion 150.

5 is a cross-sectional view for describing a light emitting module according to another embodiment of the present invention.

Referring to FIG. 5, the light emitting module according to the present embodiment is generally similar to the light emitting module described with reference to FIG. 2, but a recess 150 is formed in the circuit board 100c and the lens 300c is recessed. There is a difference between the fitting and the fitting.

That is, since the lens 300c is coupled using the recess 150 instead of the dam unit 110 of FIG. 2, the dam unit 110 does not need to be formed, and the accommodation groove is formed in the lens 300c. no need.

Furthermore, since the outer side surface of the lens 300c is fitted to the inner wall of the recess 150, it is possible to prevent the light from being lost inside the lens 300c. Further, in order to prevent light from being lost by the inner wall of the recess 150, a second recessed portion as described with reference to FIG. 3 may be formed.

6 is a cross-sectional view for describing a light emitting module according to another embodiment of the present invention.

Referring to FIG. 6, the light emitting module according to the present embodiment is generally similar to the light emitting module described with reference to FIG. 5, but has an optical sheet having an opening 175 for coupling the lens 300c to the circuit board 100d. There is a difference in that the 170 is attached and the lens 300c is coupled to the opening 175.

That is, the opening 175 of the optical sheet 170 is used instead of the recess 150 in FIG. Therefore, it is not necessary to form the recess 150 in the circuit board 100d.

7 is a cross-sectional view for describing a light emitting module according to another embodiment of the present invention.

Referring to FIG. 7, the light emitting module according to the present embodiment is substantially similar to the light emitting module described with reference to FIG. 2, but further includes a transparent resin 260 covering the light emitting diode chip 220 and the wavelength conversion layer 240. There is a difference. The transparent resin 260 covers the light emitting device in the recess 330. The transparent resin 260 may also be applied to the embodiments of FIGS. 3 to 6.

The transparent resin 260 protects the wavelength conversion layer 240 and the light emitting diode chip 220 from moisture.

(Light emitting diode chip)

Hereinafter, a manufacturing method thereof will be described in order to help the understanding of the LED chip 220.

8 to 12 are views for explaining a flip chip type light emitting diode chip manufacturing method according to an embodiment of the present invention, (a) is a cross-sectional view taken along the cutting line A-A (b) in each of the drawings.

First, referring to FIG. 8, a first conductive semiconductor layer 23 is formed on the growth substrate 21, and a plurality of mesas M spaced apart from each other on the first conductive semiconductor layer 23 are formed. Is formed. The plurality of mesas M may include an active layer 25 and a second conductivity type semiconductor layer 27, respectively. The active layer 25 is positioned between the first conductive semiconductor layer 23 and the second conductive semiconductor layer 27. Meanwhile, the reflective electrodes 30 are positioned on the plurality of mesas M, respectively.

The plurality of mesas M may be formed on the growth substrate 21 by forming an epitaxial layer including the first conductive semiconductor layer 23, the active layer 25, and the second conductive semiconductor layer 27. After growing using the same, the second conductive semiconductor layer 27 and the active layer 25 may be formed by patterning the first conductive semiconductor layer 23 to expose the first conductive semiconductor layer 23. Sides of the plurality of mesas M may be formed to be inclined by using a technique such as photoresist reflow. The inclined profile of the mesa (M) side improves the extraction efficiency of the light generated in the active layer 25.

The plurality of mesas M may have an elongated shape extending in parallel to each other in one direction as shown. This shape simplifies forming a plurality of mesas M of the same shape in the plurality of chip regions on the growth substrate 21.

Meanwhile, the reflective electrodes 30 may be formed on each mesa M after the plurality of mesas M are formed, but is not limited thereto. The second conductive semiconductor layer 27 may be grown and mesas. It may be formed in advance on the second conductivity-type semiconductor layer 27 before forming (M). The reflective electrode 30 covers most of the upper surface of the mesa M, and has a shape substantially the same as the planar shape of the mesa M. FIG.

The reflective electrodes 30 may include a reflective layer 28 and may further include a barrier layer 29. The barrier layer 29 may cover the top and side surfaces of the reflective layer 28. For example, by forming a pattern of reflective layer 28 and forming barrier layer 29 thereon, barrier layer 29 can be formed to cover the top and side surfaces of reflective layer 28. For example, the reflective layer 28 may be formed by depositing and patterning an Ag, Ag alloy, Ni / Ag, NiZn / Ag, TiO / Ag layer. Meanwhile, the barrier layer 29 may be formed of Ni, Cr, Ti, Pt, Rd, Ru, W, Mo, TiW, or a composite layer thereof to prevent the metal material of the reflective layer from being diffused or contaminated.

After the plurality of mesas M are formed, an edge of the first conductivity type semiconductor layer 23 may also be etched. Accordingly, the upper surface of the substrate 21 may be exposed. Side surfaces of the first conductivity-type semiconductor layer 23 may also be formed to be inclined.

As illustrated in FIG. 8, the plurality of mesas M may be formed to be located within the upper region of the first conductivity-type semiconductor layer 23. That is, the plurality of mesas M may be located in an island shape on the upper region of the first conductivity type semiconductor layer 23. Alternatively, as shown in FIG. 13, mesas M extending in one direction may be formed to reach the upper edge of the first conductivity-type semiconductor layer 23. That is, one side edge of the bottom surface of the plurality of mesas M coincides with one side edge of the first conductive semiconductor layer 23. Accordingly, the top surface of the first conductivity type semiconductor layer 23 is partitioned by a plurality of mesas M.

Referring to FIG. 9, a lower insulating layer 31 covering the plurality of mesas M and the first conductive semiconductor layer 23 is formed. The lower insulating layer 31 has

openings

31a and 31b to allow electrical connection to the first conductive semiconductor layer 23 and the second conductive semiconductor layer 27 in a specific region. For example, the lower insulating layer 31 may have openings 31a exposing the first conductivity type semiconductor layer 23 and openings 31b exposing the reflective electrodes 30.

The openings 31a may be positioned near the edge between the mesas M and the edge of the substrate 21, and may have an elongated shape extending along the mesas M. On the other hand, the openings 31b are limited to the upper portion of the mesa (M), and are located on the same end side of the mesas.

The lower insulating layer 31 may be formed of an oxide film such as SiO ₂ , a nitride film such as SiN _x, or an insulating film of SiON or MgF ₂ using a technique such as chemical vapor deposition (CVD). The lower insulating layer 31 may be formed of a single layer, but is not limited thereto and may be formed of multiple layers. Further, the lower insulating layer 31 may be formed of a distributed Bragg reflector (DBR) in which a low refractive material layer and a high refractive material layer are alternately stacked. For example, an insulating reflective layer having a high reflectance can be formed by laminating dielectric layers such as SiO ₂ / TiO ₂ or SiO ₂ / Nb ₂ O ₅ .

Referring to FIG. 10, a current spreading layer 33 is formed on the lower insulating layer 31. The current spreading layer 33 covers the plurality of mesas M and the first conductive semiconductor layer 23. In addition, the current spreading layer 33 has openings 33a located in the upper region of each mesa M to expose the reflective electrodes. The current spreading layer 33 may be in ohmic contact with the first conductivity type semiconductor layer 23 through the openings 31a of the lower insulating layer 31. The current spreading layer 33 is insulated from the plurality of mesas M and the reflective electrodes 30 by the lower insulating layer 31.

The openings 33a of the current spreading layer 33 have a larger area than the openings 31b of the lower insulating layer 31, respectively, to prevent the current spreading layer 33 from connecting to the reflective electrodes 30. Have Thus, sidewalls of the openings 33a are located on the lower insulating layer 31.

The current spreading layer 33 is formed over almost the entire area of the substrate 31 except for the openings 33a. Thus, current can be easily dispersed through the current spreading layer 33. The current spreading layer 33 may include a high reflective metal layer such as an Al layer, and the high reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. In addition, a protective layer of a single layer or a composite layer structure such as Ni, Cr, Au, or the like may be formed on the highly reflective metal layer. The current spreading layer 33 may have, for example, a multilayer structure of Ti / Al / Ti / Ni / Au.

Referring to FIG. 11, an upper insulating layer 35 is formed on the current spreading layer 33. The upper insulating layer 35 has openings 35b exposing the current spreading layer 33 and openings 35b exposing the reflective electrodes 30. The opening 35a may have an elongated shape in a direction perpendicular to the longitudinal direction of the mesa M, and has a relatively large area compared to the openings 35b. The openings 35b expose the reflective electrodes 30 exposed through the openings 33a of the current spreading layer 33 and the openings 31b of the lower insulating layer 31. The openings 35b may have a smaller area than the openings 33a of the current spreading layer 33, and may have a larger area than the openings 31b of the lower insulating layer 31. Accordingly, sidewalls of the openings 33a of the current spreading layer 33 may be covered by the upper insulating layer 35.

The upper insulating layer 35 may be formed using an oxide insulating layer, a nitride insulating layer, a mixed layer or a cross layer of these insulating layers, or a polymer such as polyimide, teflon, parylene, or the like.

Referring to FIG. 12, a first pad 37a and a second pad 37b are formed on the upper insulating layer 35. The first pad 37a connects to the current spreading layer 33 through the opening 35a of the upper insulating layer 35, and the second pad 37b connects the openings 35b of the upper insulating layer 35. It is connected to the reflective electrodes 30 through. The first pad 37a and the second pad 37b may be connected to bumps or used as pads for SMT to mount the light emitting diode to a submount, package, or printed circuit board.

The first and

second pads

37a and 37b may be formed together in the same process, for example using photo and etching techniques or lift off techniques. The first and

second pads

37a and 37b may include, for example, an adhesive layer such as Ti, Cr, or Ni, and a highly conductive metal layer such as Al, Cu, Ag, or Au. The first and

second pads

37a and 37b may be formed so that the end ends thereof are coplanar, and thus the light emitting diode chip 220 may be formed on the conductive patterns having the same height on the circuit boards 100a to 100d. Can be flip bonded to.

Thereafter, the growth substrate 21 is divided into individual light emitting diode chip units to complete the light emitting diode chip. The growth substrate 21 may be removed from the LED chip before or after it is divided into individual LED chip units.

Hereinafter, a structure of a light emitting diode chip according to an embodiment of the present invention will be described in detail with reference to FIG. 12.

The light emitting diode chip includes a first conductive semiconductor layer 23, mesas M, reflective electrodes 30, and a current spreading layer 33, and includes a growth substrate 21 and a lower insulating layer 31. The upper insulating layer 35 may include a first pad 37a and a second pad 37b.

The substrate 21 may be a growth substrate for growing gallium nitride-based epi layers, such as sapphire, silicon carbide, silicon, or gallium nitride substrate. The substrate 21 is, for example, a sapphire substrate, it may have a thickness of 200um or more, preferably 250um or more.

The first conductive semiconductor layer 23 is continuous, and the plurality of mesas M are spaced apart from each other on the first conductive semiconductor layer 23. The mesas M include the active layer 25 and the second conductivity-type semiconductor layer 27 as described with reference to FIG. 8 and have an elongated shape extending toward one side. The mesas M may be a stacked structure of a gallium nitride compound semiconductor. The mesas M may be limitedly positioned in an upper region of the first conductivity-type semiconductor layer 23, as shown in FIG. 8. In contrast, the mesas M may extend to one edge of the upper surface of the first conductivity-type semiconductor layer 23 in one direction, as shown in FIG. 6, and thus the first conductivity-type semiconductor layer 23. The upper surface of the can be divided into a plurality of areas. Accordingly, it is possible to alleviate the concentration of the current near the edge of the mesas (M) to further enhance the current distribution performance.

The reflective electrodes 30 are respectively positioned on the plurality of mesas M to make ohmic contact with the second conductivity-type semiconductor layer 27. As described with reference to FIG. 8, the reflective electrodes 300 may include a reflective layer 28 and a barrier layer 29, and the barrier layer 29 may cover the top and side surfaces of the reflective layer 28.

The current spreading layer 33 covers the plurality of mesas M and the first conductive semiconductor layer 23. The current spreading layer 33 has openings 33a located in the upper region of each mesa M and exposing the reflective electrodes 30. The current spreading layer 33 is also ohmic contacted to the first conductivity type semiconductor layer 23 and insulated from the plurality of mesas M. FIG. The current spreading layer 33 may include a reflective metal such as Al.

The current spreading layer 33 may be insulated from the plurality of mesas M by the lower insulating layer 31. For example, the lower insulating layer 31 may be positioned between the plurality of mesas M and the current spreading layer 33 to insulate the current spreading layer 33 from the plurality of mesas M. FIG. In addition, the lower insulating layer 31 may have openings 31b disposed in the upper region of each mesa M to expose the reflective electrodes 30, and may expose the first conductivity-type semiconductor layer 23. It may have openings 31a. The current spreading layer 33 may be connected to the first conductivity type semiconductor layer 23 through the openings 31a. The openings 31b of the lower insulating layer 31 have a smaller area than the openings 33a of the current spreading layer 33 and are all exposed by the openings 33a.

The upper insulating layer 35 covers at least a portion of the current spreading layer 33. In addition, the upper insulating layer 35 has openings 35b exposing the reflective electrodes 30. Furthermore, the upper insulating layer 35 may have an opening 35a exposing the current spreading layer 33. The upper insulating layer 35 may cover sidewalls of the openings 33a of the current spreading layer 33.

The first pad 37a may be positioned on the current spreading layer 33, and may be connected to the current spreading layer 33 through, for example, an opening 35a of the upper insulating layer 35. In addition, the second pad 37b is connected to the reflective electrodes 30 exposed through the openings 35b. As illustrated in FIG. 12, the first pad 37a and the second pad 37b may have upper ends disposed at the same height.

According to the present invention, the current spreading layer 33 covers almost the entire area of the mesas M and the first conductivity type semiconductor layer 23 between the mesas M. Thus, current can be easily dispersed through the current spreading layer 33.

Furthermore, the current spreading layer 23 includes a reflecting metal layer such as Al, or the lower insulating layer is formed as an insulating reflecting layer so that the light not reflected by the reflecting electrodes 30 is reflected by the current spreading layer 23 or the lower insulating layer. (31) can be used to reflect, thereby improving light extraction efficiency.

The flip chip light emitting diode chip according to the present embodiment may have a relatively wide directivity distribution.

14 is a graph illustrating a direct distribution of a flip chip type light emitting diode chip 240 having a conventional light emitting diode package 200 and a conformal coating layer 220 according to an embodiment of the present disclosure.

Referring to FIG. 14A, the conventional LED package 200 has a directing angle of about 120 degrees as a substantially same directing angle with respect to the X and Y directions. On the other hand, the flip-chip type light emitting diode chip 240 of the present application exhibits a direction angle of about 140 degrees which is substantially the same with respect to the X direction and the Y direction, and when the conformal coating layer is applied, as shown in FIG. Indicates the orientation angle.

Figure 15 (a) shows the directivity distribution of the light emitting module using a conventional light emitting diode package having a directivity angle of 120 degrees, Figure 15 (b) is coated with a conformal coating layer 220 having a directivity angle of 145 degrees of the present application The directivity distribution of the light emitting module using the flip chip light emitting diode chip 240 is shown. Here, the light directivity distribution in the uniaxial direction was simulated using a light emitting element and a lens having the same illuminance distribution in each direction. The light directivity distribution shows the luminous intensity according to the directivity angle at a point 5 m away from each light emitting element.

In this graph, the greater the angle between the maximum luminous intensity values, and the smaller the ratio of luminous intensity at the center to the maximum luminous intensity value (C / P), the wider and more uniformly the light is distributed. In the case of Fig. 15 (a), the angle between the maximum luminous intensity values is 146 degrees, and the ratio of the luminous intensity at the center to the maximum luminous intensity is 10%, and in Fig. 15 (b) these values are 152 degrees and 4.5, respectively. It was%. Therefore, when the light emitting module is manufactured using the flip chip type light emitting diode chip 240 in which the conformal coating layer 220 of the present application is formed, light can be dispersed more widely and uniformly than the conventional light emitting module.

FIG. 16 illustrates an illuminance distribution of a light emitting module in which 16 light emitting devices are arranged in a 4 × 4 matrix on a circuit board and a lens is coupled to each light emitting device. b) shows the illuminance distribution of the light emitting module in which the flip chip type light emitting diode chip 240 to which the conformal coating layer 220 is applied is arranged. The distance between the light sources was 100 mm and the illuminance distribution measurement distance was 23 mm.

In the case of FIG. 16 (a), the light uniformity was 79.4%, and in FIG. 16 (b), the light uniformity was 84.6%. Even when comparing FIGS. 16 (a) and (b) with the naked eye, FIG. In this case, it can be seen that the light diffusivity of the outside is superior to that of FIG.

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

Claims

A circuit board;

A light emitting device flip-bonded to the circuit board; And

A lens coupled to the circuit board, the lens dispersing light emitted from the light emitting element;

The light emitting device includes a flip chip light emitting diode chip; And

Light emitting module comprising a wavelength conversion layer coated on the light emitting diode chip.
The method according to claim 1,

The wavelength conversion layer covers a top surface and a side surface of the light emitting diode chip.
The method according to claim 1,

The circuit board has a protrusion on the upper surface,

The lens has a receiving groove for receiving the protrusion,

The lens is a light emitting module in which the receiving groove is coupled to the circuit board by receiving the protrusion.
The method according to claim 1,

Further comprising a dam formed on the circuit board,

The lens has a receiving groove for receiving the dam,

The lens is a light emitting module, the receiving groove is coupled to the circuit board by receiving the dam.
The method according to claim 4,

The dam unit is a light emitting module formed of a silicone resin or an optical sheet.
The method according to claim 1,

An optical sheet attached to the circuit board and having an opening for exposing the light emitting element;

And the lens is coupled to the circuit board by being inserted into the opening of the optical sheet.
The method according to claim 1,

The circuit board comprises a recess,

Wherein the lens is fitted into the recess and coupled to the circuit board.
The method according to claim 1,

The light emitting module further comprises a transparent resin covering the light emitting element.
The method according to any one of claims 1 to 8,

The lens has a light emitting module having an incident surface on which light emitted from the light emitting element is incident and an exit surface on which incident light is emitted.
The method according to claim 9,

The incident surface is a light emitting module inner surface of the recess located on the lower surface of the lens.
The method according to claim 10,

The concave portion includes a first concave portion and a second concave portion positioned at an inlet side of the first concave portion and enclosing the first concave portion.
The method according to any one of claims 1 to 8,

The light emitting diode chip,

A first conductivity type semiconductor layer;

A plurality of mesas spaced apart from each other on the first conductive semiconductor layer, each of the mesas including an active layer and a second conductive semiconductor layer;

Reflective electrodes positioned on the plurality of mesas, respectively, for ohmic contact with a second conductivity-type semiconductor layer; And

Covering the plurality of mesas and the first conductivity type semiconductor layer, the openings being located in the upper region of each mesa and exposing the reflective electrodes, ohmic contacting the first conductivity type semiconductor layer, and the plurality of mesas. A current spreading layer insulated from the

And the light emitting diode chip is flip bonded to the circuit board.
The method according to claim 12,

The plurality of mesas have an elongated shape extending in parallel to each other in one direction, the opening of the current dispersion layer is located on the same end side of the plurality of mesas.
The method according to claim 12,

The current dispersion layer is a light emitting module comprising a reflective metal.
The method according to claim 12,

Each of the reflective electrodes includes a reflective metal layer and a barrier metal layer, wherein the barrier metal layer covers the top and side surfaces of the reflective metal layer.
The method according to claim 12,

An upper insulating layer covering at least a portion of the current spreading layer and having openings exposing the reflective electrodes; And

And a second pad disposed on the upper insulating layer and connected to the reflective electrodes exposed through the openings of the upper insulating layer.
The method according to claim 16,

And a first pad connected to the current spreading layer.
The method according to claim 12,

A lower insulating layer disposed between the plurality of mesas and the current spreading layer to insulate the current spreading layer from the plurality of mesas,

And the lower insulating layer has openings disposed in the respective mesa upper regions and exposing the reflective electrodes.
The method according to claim 18,

Each of the openings of the current spreading layer has a wider width than the openings of the lower insulating layer such that all of the openings of the lower insulating layer are exposed.
The method according to claim 19,

A top insulating layer covering at least a portion of the current spreading layer and having openings exposing the reflective electrodes,

The upper insulating layer covers the sidewalls of the openings of the current spreading layer.
The method according to claim 18,

The lower insulating layer is a light emitting module is a reflective dielectric layer.
The method according to claim 12,

The light emitting diode chip further includes a growth substrate,

The wavelength conversion layer covers the growth substrate.