KR20140070710A

KR20140070710A - LED lighting device

Info

Publication number: KR20140070710A
Application number: KR1020120131752A
Authority: KR
Inventors: 박재현; 박병규; 이종국; 서일경
Original assignee: 서울반도체 주식회사
Priority date: 2012-11-20
Filing date: 2012-11-20
Publication date: 2014-06-11

Abstract

The present invention relates to an LED lighting device capable of replacing a conventional fluorescent lamp with excellent optical uniformity even while applying a smaller number of LED chips. According to an embodiment of the present invention, the LED lighting device comprises a heat radiation frame; a substrate which is coupled to the lower side of the heat radiation frame and on which multiple LED chips are mounted on the surface thereof; and a cover which is coupled to the lower side of the heat radiation frame to protect the substrate and to which the light emitted from the LED chips is transmitted, wherein the LED chips are configured to be formed of a frameless LED chip.

Description

LED lighting device

The present invention relates to an LED lighting device capable of replacing a fluorescent lamp, and more particularly, to an LED lighting device capable of replacing a fluorescent lamp with an LED lighting device having a smaller number of LED packages, will be.

In general, a fluorescent lamp is an illumination device that converts light into electrical energy and provides light so that an object can be identified at night or in the room or outside.

However, the fluorescent lamp has a lower energy consumption than the incandescent lamp, but the energy consumption is larger than that of the LED, and the lifetime is short. Therefore, the light intensity decreases sharply over time, There is a problem of environmental pollution.

Recently, as disclosed in Korean Patent Publication No. 2010-0012952 (Patent Document 1), LEDs (Light Emitting Diodes), which have a semi-permanent lifetime and can obtain high-efficiency illumination while consuming less power, As a light source.

Here, the LED has a junction structure of a P-type and an N-type semiconductor, and when the voltage is applied, an optoelectronic element emitting light of energy corresponding to a bandgap of the semiconductor by the combination of electrons and holes, It is faster than a light source and has a low power consumption of 20%, which has recently been used in various fields including high efficiency lighting devices.

FIG. 1 schematically shows a cross-section of a conventional fluorescent-type LED lighting apparatus. As shown in FIG. 1, a conventional fluorescent-type LED lighting apparatus 10 includes a long cylindrical- A printed circuit board (PCB) 40 having a plurality of LED packages 30 mounted in the form of an array is provided in the housing 20.

At this time, the LED package 30 is mounted on the PCB 40 using a surface mounting technology (SMT) using screen printing and reflow.

The LED chip 31 is disposed in the LED chip accommodating portion 33 on the upper side of the package body 32 and is surrounded by the reflector 34 formed along the periphery of the package body 32, An encapsulant 35, which is a mixture of a resin such as silicone and a phosphor, is molded in the portion 33.

However, the fluorescent lamp type LED lighting device is intended to replace the existing fluorescent lamp. In order to install the fluorescent lamp directly without replacing the existing fluorescent lamp, it is necessary that the standard such as the diameter and the length is the same as the existing fluorescent lamp.

Accordingly, the distance between the LED package 30 and the housing 20 is limited, and a large number of LED packages 30 are required to manufacture a fluorescent-type LED lighting device having high light uniformity.

For example, a conventional bar type fluorescent lamp has a length of 120 mm. When a fluorescent lamp type LED lighting device is manufactured in accordance with this standard, about 120 to 140 LED packages are required in order to secure light uniformity .

Therefore, in order to improve the productivity and secure the price competitiveness of the product, it is necessary to develop a fluorescent-type LED lighting device which can reduce the number of LED packages required and ensure high light uniformity.

KR 10-2010-0012952 A (2010.02.09 open)

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned needs, and it is an object of the present invention to provide a fluorescent lamp type LED lighting apparatus which has the same or better light uniformity as the conventional one, And an object of the present invention is to provide an LED lighting device having an effect of improving price competitiveness of products.

Another object of the present invention is to provide an LED lighting apparatus in which the distance from the LED light source to the cover is further increased as compared with the conventional LED lighting apparatus.

In order to achieve the above-mentioned object, a preferred embodiment of the present invention is a heat dissipation frame comprising: a heat dissipation frame; A substrate coupled to a lower side of the heat dissipation frame and having a plurality of LED chips mounted on a surface thereof; And a cover coupled to a lower portion of the heat dissipating frame to protect the substrate, the cover being exposed to light emitted from the LED chip, wherein the LED chip comprises: a first conductive semiconductor layer; A plurality of mesas spaced apart from each other on the first conductive type semiconductor layer and each including an active layer and a second conductive type semiconductor layer; Reflective electrodes positioned on the plurality of mesas and ohmic-contacting the second conductivity type semiconductor layer, respectively; And a second conductive semiconductor layer over the first conductive semiconductor layer, the second conductive semiconductor layer having an opening for covering the mesa and the first conductive type semiconductor layer, the opening for exposing the reflective electrodes located in each of the mesa upper regions, And a current-dispersive layer insulated from the light-emitting layer.

Here, the reflective electrodes include a reflective metal layer and a barrier metal layer, respectively, and the barrier metal layer covers the upper surface and the side surface of the reflective metal layer.

The LED chip may further include: an upper insulating layer covering at least a part of the current spreading layer, the upper insulating layer having openings for 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.

The semiconductor device may further include a first pad connected to the current dispersion layer.

The LED chip may further include a lower insulating layer disposed between the plurality of mesas and the current dispersion layer to insulate the current dispersion layer from the plurality of mesas, And mesa upper regions and openings for exposing the reflective electrodes.

At this time, it is preferable that the openings of the current dispersion layer have a wider width than the openings of the lower insulating layer so that the openings of the lower insulating layer are all exposed.

The LED chip may further include an upper insulating layer covering at least a part of the current dispersion layer and having openings exposing the reflective electrodes, wherein the upper insulating layer is formed on the sidewalls of the openings of the current- Lt; / RTI >

The heat radiating frame may include: a support portion on which the substrate is mounted; a first rail formed on both sides in the width direction of the support portion and on which the substrate is slidably engaged; And a second rail on which an upper end of the second rail is slidably engaged.

The heat dissipation frame may further include a heat dissipation part formed on the support part so as to form a space between the heat dissipation frame and the support part.

The heat dissipation unit includes a pair of extension portions extending upward from both sides in the width direction of the support portion and a connection portion connecting the upper ends of the pair of extension portions in a circular arc shape.

At this time, a plurality of heat radiating fins may be formed on the surface of the heat radiating portion, the heat radiating fins being spaced from each other in the width direction or the longitudinal direction of the heat radiating portion.

According to a preferred embodiment of the present invention, since the frame-less LED chip is directly mounted on the substrate, a separate package body is not required, so that the LED chip is separated from the cover by the height of the package body Accordingly, the spacing between the LED packages can be further widened as compared with the related art, so that the light uniformity can be secured while reducing the number of LED packages.

1 is a schematic sectional view of a conventional fluorescent lamp type LED lighting device.
2 is an exploded perspective view of an LED lighting apparatus according to an embodiment of the present invention.
3 is a cross-sectional view in the width direction of an LED lighting apparatus according to an embodiment of the present invention.
4 (a) is a longitudinal cross-sectional view of a conventional LED package arrangement showing an LED lighting device.
4 (b) is a longitudinal cross-sectional view of an LED lighting device to which a frameless LED chip is applied according to an embodiment of the present invention.
5 (a) is a plan view of a frame-less LED chip.
5 (b) is a sectional view taken along the line AA 'in FIG. 5 (a)

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of an LED lighting apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, Embodiments that include components replaceable as equivalents in the elements may be included within the scope of the present invention.

The term "frame-less LED chip " used herein is used to distinguish the LED chip from a conventional LED chip. The frame-less LED chip is a body that forms an outer shape of the LED chip, a reflector And a package not including the lead frame means a package in which the LED chip except for the lens portion forms the outer shape of the LED chip. Is referred to as a wafer level package in that a package of a lead frame or a submount is formed, and also referred to as a chip scale package in that the external shape of the package is close to the size of the LED chip, A "chipless board" LED package is also referred to as a "COB (chip on board) type LED package" in which an LED chip is mounted on a substrate without a component. A chip having an LED package that does not include a main body, a lead frame that forms a key figure, a reflector, and a main body. As such a frameless LED chip, a light emitting diode disclosed in Korean Patent Application No. 10-2011-0139385 .

Since the frameless LED chip does not include additional components and most processes are completed in the semiconductor production process, the time and cost required for manufacturing can be reduced, and reliability is improved. In addition, since there is no constituent element for forming the external shape of the package, there is an effect that the size of the package can be reduced, and the LED chip is mounted close to the substrate.

Example

FIG. 2 is an exploded perspective view of an LED lighting apparatus according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view in a width direction of an LED lighting apparatus according to an embodiment of the present invention.

2 and 3, the LED lighting apparatus 100 according to an embodiment of the present invention includes a heat dissipating frame 200, a substrate 300 coupled to a lower side of the heat dissipating frame 200, And a cover 400 coupled to a lower portion of the heat dissipating frame 200 to protect the substrate 300. A plurality of LED chips 500 are arrayed on the substrate 300 toward the cover 400 in an array form Respectively.

Here, the heat radiation frame 200 is for dissipating the heat generated from the LED chip 500 to the outside, and is preferably made of a metal material such as aluminum or copper having good thermal conductivity.

The heat radiating frame 200 includes a support 210 on which a substrate 300 to be described later is placed, a first rail 211 protruding downward from both sides in the width direction of the support 210, And a second rail 212 protruding outwardly in the width direction of the support portion 210. The heat dissipation portion 230 is formed on the support portion 210. [

The heat dissipating unit 230 includes a pair of extending portions 231 extending upward from both sides in the width direction at the upper end of the supporting portion 210 and a connecting portion 231 connecting the upper ends of the pair of extending portions 231 in an arc- The heat dissipating space portion 220 is formed between the support portion 210 and the heat dissipating portion 230.

At this time, heat dissipating fins (not shown) for improving the heat dissipating effect may be formed on the outer surface of the heat dissipating unit 230, and the heat dissipating fins may be formed in plural numbers in the width direction or the longitudinal direction of the heat dissipating unit 230 In this case, the cooling effect is improved as the surface area of the heat dissipating part 230 in contact with the air is increased.

The substrate 300 may be made of a plastic or a metal material and may be formed of a single member or two or more members electrically connected to each other. 1 rail 211 and is slidably engaged with the lower supporting portion 210 of the heat dissipating frame 200.

At this time, a plurality of LED chips 500 are mounted on the surface of the substrate 300 in the form of an array, and electrical connection means capable of applying a voltage to the LED chip 500 such as a wiring pattern is provided, The surface of the substrate 300 is made of bright white.

According to one embodiment of the present invention, the frameless LED chip 600 is applied as the LED chip 500, so that the number of LED packages mounted on the substrate 300 can be reduced compared to the conventional case. Will be described later with reference to Figs. 4 (a) and 4 (b).

A connector 310 to which a connection terminal 311 of an external power source is connected is connected to one side of the substrate 300; a fuse 320 for protecting a circuit when a high current or a high voltage is applied; A bridge diode 330 for supplying the current to the chip 500, and a resistor 340 for controlling the current.

The cover 400 is made of translucent plastic and is coupled to the lower part of the heat radiating frame 200 to protect the substrate 300 and to uniformly transmit light emitted from the LED chip 500.

At this time, the cover 400 has a circular arc shape in cross section as a whole, and bent portions 410 for correspondingly engaging with the second rails 212 of the heat radiation frame 200 are formed on both ends of the cover 400, As shown in Fig.

As the cover 400 and the heat dissipating unit 230 of the heat dissipating frame 200 form an arcuate shape, the bent portion 410 of the cover 400 is attached to the second rail 212 of the heat dissipating frame 200, The cover 400 forms a cylindrical shape similar to that of a conventional fluorescent lamp together with the heat radiation frame 200.

FIG. 4A is a longitudinal cross-sectional view of a conventional LED package arrangement, and FIG. 4B is a longitudinal cross-sectional view of an LED lighting device to which a frameless LED chip is applied according to an embodiment of the present invention .

According to an embodiment of the present invention, a plurality of frameless LED chips 600 are mounted on an array in the form of an array on a substrate 300, thereby reducing the number of LED packages mounted on the substrate 300 .

This is because the frameless LED chip 600 does not include the separate package body 32 or the reflector 34 and the lead frame and forms the outer shape of the LED package as the LED chip itself. The distance from the cover 400 to the package body 32 is further increased as compared with the conventional LED chip 31. At this time, a resin such as epoxy is dotted on the frameless LED chip 600 to form a lens 610.

That is, in the conventional case shown in FIG. 4 (a), the distance (h ₁ ) between the LED chip 31 and the cover 400 is smaller than the distance between the frameless LED chip 600 shown in FIG. (H ₂ ) between the _first and _second electrodes 400 are further formed.

Thus, when the angles of the light directing angles are the same, the distance d ₂ between the LED packages shown in Fig. 4 (b) is smaller than the distance d ₁ between the LED packages shown in Fig. The light uniformity can be sufficiently secured while mounting a smaller number of LED packages on the substrate 300 having the same length.

This is also true in comparison with a general chip on board (COB) type package, in which the frameless LED chip 600 has no submount, so that it is spaced apart from the cover 400 by the height of the submount, do.

Hereinafter, a frameless LED chip of LED lighting according to an embodiment of the present invention will be described in more detail with reference to FIG.

5 (a) is a plan view of a frame-less LED chip, and FIG. 5 (b) is a cross-sectional view taken along line A-A 'of FIG.

The frameless LED chip 600 includes a first conductivity type semiconductor layer 620, a mesa 630, reflection electrodes 640, a current dispersion Layer 660 and may further include a substrate 610, a lower insulating layer 650, an upper insulating layer 670 and first and second pads 681 and 682.

The substrate 610 may be a growth substrate for growing gallium nitride based epitaxial layers, such as a cyphire, silicon carbide, silicon, or gallium nitride substrate.

The first conductivity type semiconductor layer 620 is continuous and a plurality of mesas 630 are spaced apart from each other on the first conductivity type semiconductor layer 620.

The mesa 630 includes an active layer 631 and a second conductive type semiconductor layer 632, and has an elongated shape extending toward one side. Here, the mesas 630 are stacked layers of gallium nitride compound semiconductors.

At this time, the mesa 630 may be located within the upper region of the first conductivity type semiconductor layer 620, and may extend to one side edge of the first conductivity type semiconductor layer 620 So that the upper surface of the first conductivity type semiconductor layer 620 can be divided into a plurality of regions. In this case, concentration of current in the vicinity of the edge of the mesa 630 can be mitigated to further enhance the current dispersion performance.

The reflective electrodes 640 are each positioned on the plurality of mesas 630 and are ohmic-contacted on the second conductive type semiconductor layer 632. The reflective electrodes 640 may include a reflective layer 642 and a barrier layer 641 and a barrier layer 641 may cover the top and sides of the reflective layer 642. For example, the reflective layer 642 may be formed by depositing and patterning Ag, Ag alloy, Ni / Ag, NiZn / Ag, TiO / Ag layer, and the barrier layer 641 may be formed of Ni, Cr, Ti, Pt , Rd, Ru, W, Mo, TiW, or a composite layer thereof, and prevents the metal material of the reflective layer 642 from being diffused or contaminated.

The current spreading layer 660 covers the plurality of mesas 630 and the first conductivity type semiconductor layer 620. At this time, the current spreading layer 660 is located in the upper region of each mesa 630 and has openings 661 for exposing the reflective electrodes 640. The current spreading layer 660 is ohmic-contacted with the first conductivity type semiconductor layer 620 and is insulated from the plurality of mesas 630. Meanwhile, the current-spreading layer 660 may include a highly reflective metal layer such as an Al layer, and the highly reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. Further, a protective layer of a single layer or a multiple layer structure such as Ni, Cr, Au or the like may be formed on the highly reflective metal layer. For example, current spreading layer 660 may have a multi-layer structure of Ti / Al / Ti / Ni / Au.

The current spreading layer 660 may be insulated from the plurality of mesas 630 by the lower insulating layer 650. For example, the lower insulating layer 650 may be interposed between the plurality of mesas 630 and the current dispersion layer 660 to isolate the current dispersion layer 660 from the plurality of mesas 630.

At this time, the lower insulating layer 650 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 650 may be formed as a single layer, but it is not limited thereto and may be formed in multiple layers. Further, the lower insulating layer 650 may be formed of a distributed Bragg reflector (DBR) in which a low refractive index material layer and an high refractive index material layer are alternately laminated. For example, an insulating reflection layer having high reflectance can be formed by applying a layer of SiO ₂ / TiO ₂ or SiO ₂ / Nb ₂ O ₅ .

The lower insulating layer 650 may have openings 651 that are located in the upper region of the respective mesa 630 and expose the reflective electrodes 640 and openings for exposing the first conductive semiconductor layer 620 652). At this time, the current-spreading layer 660 may be connected to the first conductivity type semiconductor layer 620 through openings 652 exposing the first conductivity type semiconductor layer 620.

The openings 651 of the lower insulating layer 650 have a smaller area than the openings 661 of the current spreading layer 660 and are all exposed by the openings 661. [

The upper insulating layer 670 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, At least partially.

In addition, the upper insulating layer 670 has openings 672 for exposing the reflective electrodes 640. Further, the upper insulating layer 670 may have an opening 671 for exposing the current-spreading layer 660. The upper insulating layer 670 may cover the sidewalls of the openings 661 of the current spreading layer 660.

The first pad 681 may be located on the current spreading layer 660 and may be connected to the current spreading layer 660 through the opening 671 of the upper insulating layer 670, for example. Further, the second pad 682 is connected to the reflective electrodes 640 exposed through the openings 672.

The first pad 681 and the second pad 682 may be used as a pad for connecting the bump or for SMT to mount the LED on a submount, a package, a printed circuit board, And a highly conductive metal layer such as Al, Cu, Ag, or Au.

The frame-less LED chip 600 as described above covers the entire region of the first conductivity type semiconductor layer 620 between the mesa 630 and the mesa 630, Therefore, the current can be easily dispersed through the current dispersion layer 660. [ The current dispersion layer 660 includes a reflective metal layer such as Al or the lower insulating layer 650 is formed of an insulating reflective layer so that light not reflected by the reflective electrodes 640 can be transmitted through the current dispersion layer 660, Or the lower insulating layer 650 so that the light extraction efficiency is improved.

100: LED lighting device 200: heat radiation frame
210: support part 211: first rail
212: second rail 220:
230: heat radiating part 300: substrate
400: Cover 500: LED chip
600: frameless LED chip 610: substrate
620: first conductivity type semiconductor layer 630: mesas
640: reflection electrodes 650: lower insulating layer
660 current dispersion layer 670 upper insulating layer
681: first pad 682: second pad

Claims

Heat radiating frame;
A substrate coupled to a lower side of the heat dissipation frame and having a plurality of LED chips mounted on a surface thereof; And
And a cover coupled to a lower portion of the heat radiating frame to protect the substrate, the cover being configured to transmit light emitted from the LED chip,
Wherein the LED chip comprises:
A first conductive semiconductor layer;
A plurality of mesas spaced apart from each other on the first conductive type semiconductor layer and each including an active layer and a second conductive type semiconductor layer;
Reflective electrodes positioned on the plurality of mesas and ohmic-contacting the second conductivity type semiconductor layer, respectively; And
A plurality of mesas and a plurality of mesas, each of the plurality of mesas and the first conductivity type semiconductor layer, each of the plurality of mesas and the first conductivity type semiconductor layer having an opening for exposing the reflective electrodes, And a current-dispersed layer insulated from the light-emitting layer.

The liquid crystal display according to claim 1,
Wherein each of the reflective metal layer and the barrier metal layer includes a reflective metal layer and a barrier metal layer, the barrier metal layer covering upper and side surfaces of the reflective metal layer.

The LED package according to claim 1,
An upper insulating layer covering at least a part of the current spreading layer, the upper insulating layer having openings for 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 of claim 3,
And a first pad connected to the current dispersion layer.

The LED package according to claim 1,
And a lower insulating layer located between the plurality of mesas and the current dispersion layer to insulate the current dispersion layer from the plurality of mesas,
Wherein the lower insulating layer has openings located in the respective mesa upper regions and exposing the reflective electrodes.

The method of claim 5,
Wherein the openings of the current-spreading layer are wider than the openings of the lower insulating layer such that the openings of the lower insulating layer are all exposed.

7. The LED chip according to claim 6,
And an upper insulating layer covering at least a part of the current spreading layer and having openings exposing the reflective electrodes,
And the upper insulating layer covers sidewalls of the openings of the current spreading layer.

The heat sink according to claim 1,
A first rail formed on both sides in the width direction of the support and on which the substrate is slidably engaged and a second rail formed on both sides in the width direction of the first rail, 2 < / RTI > rail.

The heat sink according to claim 1,
Further comprising a heat dissipation part formed on the support part so as to form a space between the support part and the LED part.

[12] The heat sink according to claim 9,
A pair of extension portions extending upward from both sides in the width direction of the support portion, and connection portions connecting the upper ends of the pair of extension portions in an arc-shaped manner.

The method of claim 9,
And a plurality of radiating fins spaced apart from each other in the width direction or the longitudinal direction of the heat dissipation unit are formed on the surface of the heat dissipation unit.