KR101233731B1

KR101233731B1 - Lighting device having light emitting diode

Info

Publication number: KR101233731B1
Application number: KR1020100067013A
Authority: KR
Inventors: 김강
Original assignee: 김강
Priority date: 2010-07-12
Filing date: 2010-07-12
Publication date: 2013-02-18
Also published as: KR20120006337A

Abstract

The present invention relates to a lighting apparatus including an LED, comprising: a plurality of LED modules including a metal plate having no resin layer therein and an LED package bonded to the metal plate; A light condensing block having an inclined surface for condensing light from the LED package; A power generator for generating driving power of the LED modules; External wirings electrically connecting the power generator and the LED packages; And an insulating mesh covering the external wire connection portions.

Description

LED lighting device {LIGHTING DEVICE HAVING LIGHT EMITTING DIODE}

The present invention relates to a lighting device including the LED.

Light emitting diodes (hereinafter referred to as " LEDs ") are two-terminal diode devices comprising compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaN, and AlGaInP. LEDs emit visible light as light energy generated when electrons and holes combine when power is applied to the cathode and anode terminals.

The white LED emitting white light may be implemented as a combination of a red LED, a green LED, and a blue LED, or a combination of yellow phosphors with a blue LED. Due to the emergence of white LEDs, the application fields of LEDs have been expanded from indicators of electronic products to living goods, advertising panels, etc. It has reached a stage where it can replace a general lighting source for replacing a head lamp and a fluorescent lamp.

High power and high brightness LEDs are being applied to various lighting applications. The efficiency and lifespan of an LED gets worse as the heat generated from the LED's junction gets higher. High power and high brightness LED packages are essential for the design to dissipate heat generated from the LED chip.

About 15% of the energy applied to the LED package is converted to light and about 85% is consumed as heat. The higher the temperature of the LED chip, the higher the failure rate of the LED package.

Resin molding type LED packages do not provide an efficient heat dissipation structure in LED chips of 0.2W / mK or more due to the low thermal conductivity of plastic resins. For this reason, the resin molding type LED package is used for the indicator which uses an LED chip of 0.1 W or less, and low brightness.

In order to improve the heat dissipation structure of the resin-molded LED package, a heat sink made of copper (heat conductivity 300 -400 W / mK) or aluminum (heat conductivity 150-180W / mK) is provided under the LED chip. A package structure was built that embeds the. Resin molding type LED package with built-in heat sink can be applied to LED package of more than 0.1W by using direct heat dissipation through heat sink metal, so it can be applied to LED package of more than 0.1W, but heat between resin material and metal core for heat sink Cracks occur between them due to the expansion coefficient difference, which causes a problem in reliability.

In order to improve the heat dissipation structure, the LED package body may be used as a metal. As the material of the package body, aluminum, copper, or the like may be used. This structure has excellent heat dissipation characteristics, but due to the transparent silicon filling in the light emitting area, the gold wire connecting the electrode surface of the LED chip is boiled or the silicon (or Cracks occur at the interface between the resin) and the metal, and there is a problem in reliability such as electrode oxidation due to moisture or air penetration.

LED packages using ceramic as the package body material can be used in LED packages that require high reliability due to their excellent environmental resistance, low coefficient of thermal expansion, UV resistance, and surface bonding with silicon. As the ceramic material, alumina or low temperature co-fired ceramic (LTCC) materials may be used. The thermal conductivity of alumina is 15-20W / mK, which is lower than metal, but suitable for 0.2-1W class LED packages. LTCC is difficult to use in high-power LED packages due to its low thermal conductivity of 3W / mK. In order to remedy this weakness, an attempt is made to form a thermal via hole in the LED package and to fill a metal such as silver therein to increase heat dissipation efficiency through the thermal via hole.

The array-type LED package developed by Laminar Ceramics in the United States simultaneously fires metals and ceramics with similar thermal expansion coefficients, enabling inter-electrode insulation through ceramic layers and designing electrodes and circuits on the ceramics. Therefore, the heat generated from the LED chip is designed to dissipate through the metal to realize excellent performance in heat dissipation. However, this LED package has the disadvantage of having a very high manufacturing cost because it requires the selection of expensive special materials to simultaneously sinter heterogeneous ceramics and metals, and requires very complicated process control.

The above-described conventional LED packages are mostly soldered onto expensive metal printed circuit boards or other thermal clad boards for heat dissipation. In this case, the heat generated in the LED package is dissipated through the metal PCB. Metal PCB is a resin layer on an aluminum metal substrate. It has a structure in which a copper foil layer and a solder resist layer are laminated. The resin layer serves to electrically insulate the copper foil layer through which the current flows and the metal substrate layer thereunder, and form a heat transfer path between the copper foil layer and the metal substrate layer below. Heat generated from the LED package is primarily conducted through the copper foil layer of the metal PCB, and the heat thus conducted is transferred to the lower metal substrate through the resin layer. Therefore, to make the heat dissipation structure more efficient, the thermal conductivity of the resin layer must be increased. The thermal conductivity of the resin layer used in the metal PCB is about 1.0-2.2 W / mk. In metal PCBs, there is a need for a reliable bonding of two metals having opposing combinations of aluminum and copper foil with a resin layer interposed therebetween and having different coefficients of thermal expansion, and a method of reducing the stress between the two metals during bonding performance and thermal expansion. It is becoming. The thermal expansion coefficient of copper is about 17 ppm / K, and the thermal expansion coefficient of aluminum is about 25 ppm / K. In order to satisfy the required performance of the resin layer of the metal PCB as described above, the thickness of the resin layer used in the metal PCB is relatively thick, such as 0.075-0.30mm, and due to the thickness of the resin layer, the thickness of the resin layer between the copper foil layer and the metal substrate There is a problem where heat flow is not desired. Specifically, the heat transfer of the metal PCB, the heat generated from the LED chip is radiated along the heat transfer path through the package body, solder layer, copper foil layer, resin layer, aluminum substrate, due to the low thermal conductivity of the resin layer The resin layer in the flow causes a bottle neck of heat release.

LED lighting devices are spotlighted as the next-generation eco-friendly lighting devices due to the advantages of LED devices such as semi-permanent life, low power consumption, high brightness. In order to increase the competitiveness of the LED lighting device, it is essential to improve the heat dissipation structure of the above-described LED package. The applicant of Korean Patent Application No. 10-2010-0025801 (2010. 03. 23), the applicant of the present invention by directly bonding the LED package to the metal plate (or heat sink) without the resin layer of the heat flow due to the resin layer of the existing metal PCB In order to prevent bottlenecks, we have proposed a method to maximize heat dissipation efficiency and lower product cost. Application of the proposed LED package can maximize the competitiveness of LED lighting devices. However, in order to apply the proposed LED package to a lighting device, a light condensing structure suitable for the lighting device is required, and a design of an assembly structure that can easily replace a problematic LED is required.

The present invention provides an LED lighting device having an assembling structure that increases heat dissipation effect, enhances light collecting effect, and is easily replaced using a low-cost metal plate.

In one aspect of the present invention, the LED package of the present invention comprises a plurality of LED modules including a metal plate and a LED package bonded to the metal plate therein; A light condensing block having an inclined surface for condensing light from the LED package; A power generator for generating driving power of the LED modules; External wirings electrically connecting the power generator and the LED packages; And an insulating mesh covering the external wire connection portions.
The metal plate is any one of a copper plate and an aluminum plate with nickel plating on its surface.
An insulating layer is formed on the surface of the metal plate except the bonding surface of the LED package and the metal plate.

According to the present invention, the LED package is integrally bonded to a metal plate or a heat sink in which there is no resin layer therein, thereby increasing the heat dissipation efficiency of the LED package and lowering the manufacturing cost by using a low-cost metal plate or a heat sink. Furthermore, the present invention manufactures the LED package bonded to the metal plate in an easy-to-replace LED module structure and assembled the LED module together with the light condensing block to increase the condensing effect of the LED lighting device and to easily replace the LED package at the end of life. can do. The LED lighting device of the present invention can be applied to any lighting device described in the background art.

1 is a cross-sectional view showing an LED module according to a first embodiment of the present invention.
FIG. 2 is an equivalent circuit diagram illustrating an LED chip and a zener diode embedded in the LED package shown in FIG. 1.
3 and 4 are cross-sectional views illustrating a structure for preventing a short circuit between lead frames of the LED package when the LED package is bonded to the metal plate.
5 is an exploded perspective view showing the structure of the LED module and the light collecting block.
6 is a cross-sectional view of the LED module and the light collecting block.
7 is a cross-sectional view illustrating an example in which a plurality of LED modules are connected to external wiring through pins and connectors 21.
8 is a circuit diagram illustrating an example in which LED modules are connected in series between a positive terminal and a negative terminal of a power generator.
9 is a plan view illustrating an example in which a plurality of LED modules are arranged in a matrix form and the LED modules are connected to a power generator.
10 is a cross-sectional view illustrating an LED module and a light collecting block according to a second embodiment of the present invention.
FIG. 11 is a plan view illustrating a wiring connection example of the LED modules of FIG. 10.
12 is a plan view illustrating another example of wiring connections of the LED modules of FIG. 10.
13 is a cross-sectional view showing the overall structure of the LED lighting apparatus according to the embodiment of the present invention.

According to the present invention, the solderable metal is coated on the entire bottom of the package body and the bottom of the LED package is directly soldered to a low-cost metal plate (or heat sink) or the LED is embedded through the metal embedded body (or metal core) embedded in the package body. The package is soldered directly to a metal plate (or heat sink). Here, the metal plate (or heat sink) means a low-cost metal plate without any resin layer therein. Due to this heat dissipation structure, the LED package of the present invention can release the heat of the LED package to the outside without the bottleneck in the heat transfer path. The metal plate may be selected from copper plate or aluminum plate with nickel plating on the surface to allow soldering. The solder material is a metal having a content of 96.5% of tin (Sn), 3% of silver (Ag), and about 0.5% of copper (Cu). The metal plate and the LED package may be bonded with an adhesive (or bonder) such as Ag epoxy having a relatively high thermal conductivity. The metal plate may be connected to ground voltage source GND and grounded. The heat dissipation method of the LED package is applicable to the bonding method of the metal plate and the LED package disclosed in Korea Patent Application No. 10-2010-0025801 (2010. 03. 23) or the structure thereof.

The LED module described in the following embodiments is a replaceable unit including a metal plate and an LED package directly bonded to the metal plate, and has a structure that can be easily replaced without a high degree of replacement technology. The light collecting block may be stacked on the LED module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 and 2, the LED module according to the first embodiment of the present invention includes a metal plate 30 and an LED package 100. The metal plate 30 may be replaced with a metal heat sink.

The LED package 100 may be soldered directly onto the metal plate 30 or adhered to the metal plate 30 with Ag epoxy adhesive. The LED package 100 includes a package body 11, an anode lead frame 12, a cathode lead frame 13, and a lens 14. The package body 11 may be formed of resin or a ceramic material. The LED chip 15 is mounted on the package body 11. The anode electrode of the LED chip 15 is connected to the anode lead frame 12 through a gold wiring, and the cathode electrode of the LED chip 15 is connected to the cathode lead frame 13 through a gold wiring. The lead frames 12, 13 protrude outward through the side of the package body 11. The lens 14 seals the LED chip as a resin encapsulant to protect the LED chip from physical shocks, infiltration of oxygen and moisture, and condenses light from the LED chip.

The package body 11 may include a metal plate 30 and a solderable metal core 11a. To this end, a via hole is formed in the package body 11, and the metal of the metal core 11a may be filled in the via hole. The metal core 11a contains copper (Cu), nickel (Ni), silver (Ag), or an alloy thereof. In addition, a bottom metal layer (not shown) may be formed on the bottom of the package body 11 to allow soldering with the metal plate 30. The metal core 11a of the package body 11 or the bottom metal layer of the package body 11 may be directly bonded to the metal plate 30 with an adhesive such as soldering or Ag epoxy.

The LED package 100 may include a Zener diode 16 connected in parallel with the LED chip 15 through the metal core 11a as shown in FIG. 2. The anode electrode of the LED chip 15 is connected to the cathode electrode of the zener diode 16 through the metal core 11a, and the cathode electrode of the LED chip 15 is connected to the anode electrode of the zener diode 16. Meanwhile, the bottom metal layer of the package body 11 is not connected to the LED chip 15 and the zener diode 16.

When the LED package 100 is bonded to the metal plate 30 as it is, the anode lead frame 12 and the cathode lead frame 13 of the LED package 100 are in contact with the metal plate 30, and the lead frames 12 and 13 are connected. It is short-circuited. Therefore, in the present invention, the anode lead frame 12 and the cathode lead frame 13 of the LED package 100 are lifted up as shown in FIGS. 3 and 4 to be spaced apart from the metal plate 30. An anode lead frame of the LED package 100 as shown in FIGS. 3 and 4 in order to apply current from an external power generator 203 of FIG. 13 to the LED package 100 or to connect in series with another LED package 100. 12 and the cathode lead frame 13 may be connected to the external wires 20 by soldering 18. In order to reliably maintain the insulation between the lead frames 12 and 13 of the LED package 100 and the metal plate 30, the present invention is similar to the lead frames 12 and 13 of the LED package 100 as shown in FIG. 3. The joint portion of the external wiring 20 is covered with an insulating tape 19 or an insulating tube (heat shrink tube), or as shown in FIG. 4, on the metal plate 30 between the lead frames 12 and 13 and the metal plate 30. An insulating pad or an insulating layer 32 can be formed in the. The insulating pad or the insulating layer 32 should be attached to the surface of the other metal plate 30 except for the bottom portion of the LED package 100 and the bonding portion of the metal plate 30. Therefore, the insulating pad or the insulating layer 32 may be attached only to a part of the metal plate 30 opposite to the junction portion of the lead frames 12 and 13 and the external wiring 20. The insulating layer 32 may be replaced with a reflective sheet to increase the lighting efficiency.

5 and 6 are views showing the structure of the LED module and the light collecting block.

5 and 6, a light collecting block 40 is stacked on the LED module.

The light collecting block 40 may be manufactured by plastic or resin injection molding. The light collecting block 40 may have a lens insertion hole 41 through which a lens of the LED package 100 penetrates to expose the light emitting portion of the LED module, and an inclined surface 40a may be formed to collect LED light. . The inclined surface 40a may be a flat surface as shown in FIG. 5, and may be formed in a curved surface. The angle of the inclined surface 40a may be adjusted within a range of 10 ° to 60 ° according to the application field and purpose of use of the LED lighting device of the present invention. The inclined surface 40a may be coated with a metal or other material having a high reflectance to increase reflectivity. The light collecting block 40 may be fastened to the housing 201 of FIG. 13 through a screw or a hook, and may be fastened to the metal plate 30 of the LED module in a screw or screwless fastening manner. The light collecting block 40 may be assembled to the number of LED modules in the LED lighting device. Also, in the LED lighting device, the plurality of light collecting blocks 40 may be integrated into one component.

When the LED lighting device is implemented as a conventional lighting device such as an incandescent lamp, a fluorescent lamp, a street lamp, a stand lighting, the LED module and the light collecting block 40 are in an inverted state of the structure shown in FIGS. 5 and 6, that is, as shown in FIG. 13. The light emitting surface of the LED module and the inclined surface of the light collecting block 40 are assembled in the LED lighting device to face downward. Therefore, since the LED module is mounted upside down on the light collecting block 40 fixed to the housing (201 of FIG. 13), the LED module may be assembled only by being seated on the light collecting block 40 without screw fastening or adhesive. The wiring insertion hole 31 may be formed in the metal plate 30 of the LED module so that the external wiring 20 may be drawn out to the outside.

LED lighting devices generally require a large number of LED modules. Therefore, in the LED lighting device, a plurality of LED modules are assembled on the same plane as shown in FIGS. 7 to 12 and connected to the positive and negative terminals (+,-) of the power generation circuit. A mesh 50 formed of an insulating material such as plastic may be disposed between the LED modules and the rear cover 202 of FIG. 13. The mesh 50 prevents contamination of the LED module and passes heat of the metal plate 30 to the outside.

The wiring insertion hole 31 may be formed in the metal plate 30 of the LED module so that the external wiring 20 may be drawn out to the outside. The external wiring 20 for connecting the neighboring LED modules is connected to the pin and the connector 21 as shown in FIG. 7 to facilitate separation. The neighboring LED modules are connected to the external wiring 20 and connected in series to the power generator 203 or the inverter as shown in FIGS. 8 and 13.

The LED modules of the present invention may be arranged in a matrix form as shown in FIG. 9 in the LED lighting device. In the example of FIG. 9, each of the LED modules is bonded with one LED package 100 to one metal plate.

10 is a cross-sectional view illustrating an LED module and a light collecting block according to a second embodiment of the present invention.

Referring to FIG. 10, each of the LED modules includes a plurality of LED packages 100 bonded to one metal plate 60. 10 are connected to the power generator 203 of FIG. 13 in the form of FIG. 11 or 12. In the case of FIG. 11, the LED packages 100 in the LED module are connected in series and the LED modules are connected in parallel between the positive and negative terminals of the power generator 203 of FIG. 13. In the case of FIG. 12, the LED packages 100 in the LED module are connected in series with the LED packages of other neighboring LED modules. And in FIG. 12, the LED packages 100 of the first LED module (leftmost LED module in the figure) are connected in parallel to the positive terminal of the power generator 203 of FIG. 13 and the last LED module (in the figure). The LED packages 100 of the rightmost LED module are connected in parallel to the negative terminal of the power generator.

13 is a cross-sectional view showing the overall structure of the LED lighting apparatus according to the embodiment of the present invention.

Referring to FIG. 13, the LED lighting apparatus of the present invention generates an LED module, metal plates 30 and 60, a power generator 203, a housing 201, a rear cover 202, and a transparent window 204. The light collecting block 40 is fixed to the housing 201 so that the inclined surface 40a faces downward. The LED modules are seated on the back of the light collecting block 40 so that the LED emitting surface faces downward. The power generator 203 is fixed to the rear cover 202 or the housing 201. The rear cover 202 and the housing 201 may be made of metal or plastic. The transparent window 204 transmits LED light and may include a diffusion lens or a condenser lens.

When replacing an LED module that has reached the end of its life or has a problem, the housewife can easily replace the LED module without the assistance of a professional maintenance manager. For example, after the user removes the housing 201 of FIG. 13 from the rear cover 202 in FIG. 13 and the light collection block 40 from the housing 201 of FIG. 13, the user connects the external wiring connected to the end-of-life LED block. After removing the pin and connector 21 of 20, the LED block which has reached the end of its life can be separated from the LED lighting device. Subsequently, the user can easily replace the LED block at the end of its life with the new LED block by connecting the external wiring 20 of the new LED block to the external wiring 20 of another LED block neighboring by a pin and connector connection method. Since the LED modules such as FIG. 10 have a plurality of LED packages 100 bonded to one metal plate 60, the LED modules may be replaced in units of LED modules to which a LED package having a problem occurs during replacement.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

30, 60: metal plate (or heat sink) 100: LED package
20: external wiring 21: pins and connectors

Claims

A plurality of LED modules including a metal plate having no resin layer therein and an LED package bonded to the metal plate;
A light condensing block having an inclined surface for condensing light from the LED package;
A power generator for generating driving power of the LED modules;
External wirings electrically connecting the power generator and the LED packages; And
An insulating mesh covering the external wirings,
The metal plate is any one of a copper plate and an aluminum plate with a nickel plating on the surface thereof,
LED lighting device, characterized in that the insulating layer is formed on the surface of the metal plate except the bonding surface of the LED package and the metal plate.

The method of claim 1,
And a pin and a connector for connecting the external wires.

The method of claim 1,
The LED modules are LED lighting device, characterized in that seated on the back of the condensing block so that the light emitting surface is directed downward through the lens insertion hole of the condensing block.

3. The method according to claim 1 or 2,
Each of the LED modules,
One metal plate and one LED package directly bonded to the metal plate,
The LED modules are arranged in a matrix form and is connected in series between the positive terminal and the negative terminal of the power generator via the external wiring.

3. The method according to claim 1 or 2,
Each of the LED modules,
A metal plate and a plurality of LED packages directly bonded to the metal plate,
LED packages in the LED module are connected in series through the external wirings, the LED module is characterized in that connected in parallel between the positive terminal and the negative terminal of the power generator.

3. The method according to claim 1 or 2,
Each of the LED modules,
A metal plate and a plurality of LED packages directly bonded to the metal plate,
The LED packages in the LED module are connected in series with the LED package of another neighboring LED module,
The LED packages of the first LED module connected to the positive terminal of the power generator among the LED modules are connected in parallel to the positive terminal of the power generator, the LED of the last LED module connected to the negative terminal of the power generator LED lighting device, characterized in that the packages are connected in parallel to the negative terminal of the power generator.