KR20080005762A - Light-emitting module - Google Patents

Abstract

A light emitting module is provided to prevent an external deformation of a light emitting device by increasing an insulation property and decreasing a thermal expansion coefficient of the light emitting module. A light emitting module comprises a substrate(110), a wiring pattern(120), and a light emitting element(130). The substrate is formed by using a heat conduction plastic. The wiring pattern is formed on the substrate. The light emitting element is mounted on the substrate and electrically connected to the wiring pattern. The heat conduction plastic is formed by using a material, which is selected from the group consisting of ABS(Acrylonitride Butadiene Styrene), liquid crystal polymer, polyamide 4,6, polyphenylene sulfide, thermal plastic elastomer, thermal plastic sulcarnate, or a combination thereof.

Description

Light Emitting Device Module {LIGHT-EMITTING MODULE}

1 illustrates a conventional light emitting module structure in which a light emitting diode is mounted.

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

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

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

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

6 is a graph comparing the overall heat transfer coefficients of ordinary plastics, thermally conductive plastics and aluminum in a given system.

<Explanation of symbols for the main parts of the drawings>

100,200: light emitting element module 110,210: heat dissipation board

120,220: Wiring pattern 130: LED lamp

230: LED chip

The present invention relates to a light emitting device module, and more particularly, to a light emitting device module having improved heat radiation characteristics of a substrate on which a light emitting device is mounted.

CRT (Cathode Ray Tube), which is one of the display devices that are generally used, is mainly used for monitors such as televisions, measuring instruments, information terminals, computers, and the like. However, since the CRT is relatively heavy and occupies a large volume, it cannot actively cope with the demand for miniaturization and light weight of the electronic product on which the CRT is mounted.

Accordingly, flat panel displays have been developed to meet the trend of miniaturization and weight reduction of various electronic products. Specifically, liquid crystal displays (LCD) using electro-optic effects, and plasma displays (PDP: plasma display) using gas discharge. EL and EL display devices using an electroluminescent effect. Liquid crystal displays and other flat panel displays solve the problems of weight and size of conventional CRTs, and among them, research on liquid crystal displays has been actively conducted.

Compared with the CRT display device, the liquid crystal display device has the advantages of miniaturization, light weight, and low power consumption, and is recently used as a monitor of a general desktop computer, and furthermore, a monitor for a notebook computer, a large flat-panel television, and a small multimedia. It is widely used as a display device of various electric devices such as a player.

Since the liquid crystal display cannot emit light by itself, an external light source is required for light emission. In general, a backlight unit is provided on the back of the liquid crystal panel to provide light. Light sources used in the backlight unit include EL (Electro Luminescence), CCFL (Cold Cathode Fluoresecnt Lamp), FFL (Flat Fluoresecnt Lamp), and LED (Light Emitting Diode). Initially, CCFL was used a lot as a light source. However, since LEDs have many advantages, such as high color reproducibility, no mercury-free, low power consumption, high life, low power consumption, eco-friendliness, and thinning, compared to CCFL, the use of LED lamps as a light source has recently increased. LEDs, or light emitting diodes, are expected to lead the light source market in 2008.

The light emitting diode has the above advantages, but has a low light efficiency. The light-emitting efficiency of the light emitting diode is about 20 to 30%, and the remaining 70 to 80% is consumed by heat. If the heat generated from the light emitting diodes is not radiated to the outside, the light efficiency is drastically reduced and the life of the light emitting diodes may be shortened. In addition, by increasing the internal temperature of the display device equipped with the light emitting diode, it is possible to reduce the operation reliability of the peripheral drive circuit and the LCD panel.

1 illustrates a conventional light emitting module structure in which a light emitting diode is mounted.

Referring to FIG. 1, the conventional light emitting module 10 includes a substrate 12, an insulating layer 14 formed on the substrate 12, a wiring pattern 16 formed on the insulating layer 14, and a light emitting diode ( 20). In order to discharge heat generated by the light emitting diodes 20, the substrate 12 is generally formed using aluminum. Since aluminum is electrically conductive, an insulating layer 14 may be formed on the aluminum substrate 12 to prevent short between the elements. The light emitting diode 20 is electrically connected to the wiring pattern 16, and the wiring pattern 16 forms an electric circuit on the insulating layer 14 to supply power to the light emitting diode 20.

Conventional light emitting modules have the following problems.

First, the aluminum substrate 12 for heat dissipation accounts for about 30% of the price of the backlight unit using the LED, and serves as a big obstacle when the backlight unit using the LED enters the light source market. In particular, in the trend of increasing the size of the backlight unit, such as LCD TV, the problem of increased cost due to the aluminum substrate will be more serious.

Second, it is necessary to change the structure of the substrate for efficient heat dissipation. Since the aluminum substrate is made of a metal material, it is not easy to form and machine, and may cause an increase in processing cost.

Third, to form an insulating layer 14 for electrically insulating the aluminum substrate 12, the heat dissipation characteristics may be reduced due to the high thermal resistance at the interface, the welded portion and the insulating layer 14 of the light emitting diode May cause deformation.

The present invention is to solve the above problems, an object of the present invention is to provide a light emitting device module excellent in insulating properties and heat dissipation characteristics.

Another object of the present invention is to provide a light emitting device module having a low manufacturing cost, a free design, low thermal deformation, high insulation and excellent heat dissipation characteristics.

According to an exemplary embodiment of the present invention, the light emitting device module may include a substrate made of a plastic material, a wiring pattern formed on the substrate, and a light emitting device. The substrate may be provided using a plastic having electrical insulation and thermal conductivity, and since the substrate has electrical insulation and thermal conductivity, wiring and elements may be formed directly on the substrate without forming a separate insulating layer or insulating film. have.

As the substrate, a thermally conductive plastic having a thermal conductivity of about 2 W / mK or more is used.Acrylobutadiene styrene (ABS) resin, liquid crystal polymer (LCP) resin, polyamide 4,6 (PA 4, 6) -based resin, polyphenylene sulfide (PPS) -based resin, thermoplastic elastomer (TPE) -based resin, thermoplastic silicone carbonate (TPSiV) -based resin or a combination thereof.

Since the substrate can be manufactured by plastic injection molding or compression molding, it is possible to mold at a time to a specific shape without any processing, and also complex shapes such as heat fins can be molded together. The heat dissipation fin may be formed in various shapes such as a plate shape or a rod shape.

According to another exemplary embodiment of the present invention, an LED lamp may be directly mounted on a substrate using an LED lamp as a light emitting device, and after the LED chip is formed in the substrate using an LED chip as a light emitting device, It can also be mounted in the receiving groove.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the following description, and the same or similar elements may refer to the same or similar reference numerals.

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

Referring to FIG. 2, the light emitting device module 100 may be mounted on the heat dissipation substrate 110, the wiring pattern 120 formed on the heat dissipation substrate 110, and the heat dissipation substrate 110. And an LED lamp 130 that is electrically connected with the. The heat dissipation substrate 110 is formed using a thermally conductive plastic, and the wiring pattern 120 is formed on the heat dissipation substrate 110 without any insulation treatment. In another exemplary embodiment of the present invention, an insulating layer may be formed between the heat dissipation substrate and the wiring pattern, but the insulating layer is not necessarily required as conventionally.

The heat dissipation substrate 110 may be acryl butadiene styrene (ABS) resin, liquid crystal polymer (LCP) resin, polyamide 4,6 (PA 4,6) resin, polyphenylene sulfide (PPS) resin, thermoplastic It may be composed of a resin (TPE) -based resin, a thermoplastic silicone carbonate (TPSiV) -based resin, or a combination thereof, and may be molded by injection molding or compression molding similarly to conventional plastics.

Since the conventional plastic molding method is used, the heat dissipation substrate 110 may be produced in a large amount, and the heat dissipation substrate 110 having various sizes and shapes may be inexpensively produced by changing molds. In particular, in order to mount the backlight unit, flanges, screw holes, or the like must be formed in the heat dissipation board. Since these are almost provided together by plastic molding, the process of assembling the LCD display device can be very simple.

After molding the heat dissipation substrate 110, the wiring pattern 120 may be formed on the heat dissipation substrate 110. In order to form the wiring pattern 120, various wiring forming methods may be used. For example, after the metal film is formed on the heat dissipation substrate 110, the unnecessary metal film may be removed to form a desired wiring pattern. In addition, as in screen printing, a conductive ink may be directly printed on the heat dissipation substrate 110 to form a desired wiring pattern 120. As mentioned above, since the heat dissipation substrate 110 is electrically insulating, it is not necessary to perform an insulation treatment before forming the wiring pattern 120. Copper, silver, and the like may be used as the wiring pattern 120, and may include a pad portion electrically connected to the LED lamp 130 and a wiring portion for circuit configuration.

After the wiring pattern 120 is formed, the LED lamp 130 is mounted thereon. The LED lamp 130 is mounted on the heat dissipation substrate 110 by welding or soldering, and at this time, a wire connection method or a flip chip connection method for electrically connecting the LED lamp 130 and the wiring pattern 120. And the like can be used.

After mounting the LED lamp 130, a coating layer may be formed to protect the wiring pattern 120. The coating layer may protect the wiring pattern 120 from scratches, and may prevent the wiring pattern 120 from being oxidized.

As shown, a plurality of LED lamps 130 may be mounted on one heat dissipation board 110, and the light emitting device module 100 including the plurality of LED lamps 130 may be a backlight of an LCD television or an LCD monitor. Can be used for units Alternatively, after dicing the heat dissipation substrate 110 to a required size for a small LCD backlight unit, a light emitting device module having a desired size can be manufactured, and the heat dissipation substrate 110 is diced for each LED lamp, and each independent light emitting element Modules may also be manufactured. That is, as illustrated in FIG. 2, the heat dissipation substrate 110 may be diced to provide a light emitting device module including one LED lamp 130.

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

Referring to FIG. 3, an LED chip 230 is used as a light emitting device instead of an LED lamp, and a receiving groove 215 is formed in the heat dissipation substrate 210 to install the LED chip 230. The light emitting device module 200 according to the present exemplary embodiment may also be mounted on the heat dissipation substrate 210, the wiring pattern 220 formed on the heat dissipation substrate 210, and the heat dissipation substrate 210, and the wiring pattern 220. LED chip 230 is electrically connected. The heat dissipation substrate 210 may be formed using a thermally conductive plastic, and the wiring pattern 220 may be directly formed on the heat dissipation substrate 210 without additional insulation treatment.

The heat dissipation substrate 210 may be acrylobutadiene styrene (ABS) resin, liquid crystal polymer (LCP) resin, polyamide 4,6 (PA 4,6) resin, polyphenylene sulfide (PPS) resin, thermoplastic It may be composed of a resin (TPE) -based resin, a thermoplastic silicone carbonate (TPSiV) -based resin, or a combination thereof, and may be molded by injection molding or compression molding similarly to conventional plastics. By using injection or compression molding, the heat dissipation substrate 210 may be produced inexpensively and quickly, and the heat dissipation substrate 210 of various sizes and shapes may be simply produced.

Receiving grooves 215 are formed in the heat dissipation substrate 210. The accommodating groove 215 is a space for installing the LED chip 230, and the accommodating groove 215 may be formed concave in order to concentrate light generated from the LED chip 230 in one direction. Or hemispherical or the like.

After molding the heat dissipation substrate 210, a wiring pattern 220 may be formed on the heat dissipation substrate 210. In order to form the wiring pattern 220, various wiring forming methods such as patterning and screen printing may be used. Since the heat dissipation substrate 210 is electrically insulating, it is not necessary to perform an insulation treatment before forming the wiring pattern 220. Copper, silver, and the like may be used as the wiring pattern 220, and may include a pad portion electrically connected to the LED chip 230 and a wiring portion for circuit configuration. The pad portion electrically connected to the LED chip 230 may be located in the accommodation groove 215 or may be located outside the accommodation groove 215.

After the wiring pattern 220 is formed, the LED chip 230 is mounted in the receiving groove 215. The LED chip 230 is mounted on the heat dissipation substrate 210 by welding or soldering, and at this time, a wire connection method or a flip chip connection method for electrically connecting the LED chip 230 and the wiring pattern 220. And the like can be used.

In general, the LED chip has a horizontal type (vertical type) and vertical type (vertical type). As shown in the right side of Figure 3, the bottom terminal of the LED chip 230 in the vertical manner is connected to the wiring pattern 220 of the receiving groove 215, the upper terminal of the receiving groove 215 using a wire. It may be connected to the outer wiring pattern 220. In addition, as shown in the left side of FIG. 3, the terminals separated from each other at the bottom of the LED chip 231 in the horizontal manner may be connected to other wiring patterns 221 formed in the accommodation grooves 215, respectively.

After mounting the LED chip 230, a coating layer may be formed to protect the wiring pattern 220. The coating layer may protect the wiring pattern 220 from scratches and may prevent the wiring pattern 220 from being oxidized. Before or after the LED chip 230 is mounted, a coating layer having good reflection characteristics may be formed on the surface of the receiving groove 215. In general, silver coating having good reflecting properties is possible.

As mentioned above, a plurality of LED chips 230 may be mounted on one heat dissipation substrate 210, and after dicing the heat dissipation substrate 210 to a required size, a light emitting device module having a desired size may be manufactured. have.

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

Referring to FIG. 4, the light emitting device module 300 is mounted on the heat dissipation substrate 310, the wiring pattern 320 formed on the heat dissipation substrate 310, and the heat dissipation substrate 310. And an LED lamp 330 electrically connected thereto. The heat dissipation substrate 310 is formed using the above-described heat conductive plastic, and the wiring pattern 320 is formed on the heat dissipation substrate 310 without any insulation treatment.

The heat dissipation fin part 340 is formed on the bottom of the heat dissipation substrate 310. The heat dissipation fin part 340 is composed of a plurality of heat dissipation fins 342, and a plurality of heat dissipation fins 342 is formed in a plate shape or a rod shape. The heat dissipation fin 342 may be formed of the same heat conductive plastic as the heat dissipation substrate 310, or may be provided by attaching another material such as aluminum to the bottom surface of the heat dissipation substrate 310. In this embodiment, the heat dissipation fin 342 is molded together with the heat dissipation substrate 310 through a plastic molding process.

Since the plastic molding process is used, it is very easy to mold the heat radiation fins 342 on the bottom surface of the heat radiation substrate 310. In order to make a heat dissipation fin in a conventional aluminum substrate, the aluminum base material must go through a complicated process of cutting and trimming, but in this embodiment, the heat dissipation fin 342 can be made at a time by molding. In addition, in the shape of the heat radiation fin 342, the space therebetween can have a rectangular or arcuate cross section, and in this embodiment, the space 344 which has a rectangular cross section is formed.

After molding the heat dissipation substrate 310, a wiring pattern 320 may be formed on the heat dissipation substrate 310. In order to form the wiring pattern 320, various wiring forming methods such as patterning and screen printing may be used. Copper, silver, and the like may be used as the wiring pattern 320, and may include a pad portion electrically connected to the LED lamp 330 and a wiring portion for circuit configuration.

After the wiring pattern 320 is formed, an LED lamp 330 is mounted thereon. The LED lamp 330 is mounted on the heat dissipation board 310 by welding or soldering, and at this time, a wire connection method or a flip chip connection method for electrically connecting the LED lamp 330 and the wiring pattern 320. And the like can be used.

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

Referring to FIG. 5, the light emitting device module 400 is mounted on the heat dissipation substrate 410, the wiring pattern 420 formed on the heat dissipation substrate 410, and the heat dissipation substrate 410, and the wiring pattern 420. LED chip 430 is electrically connected to the. The heat dissipation substrate 410 is formed using the above-described heat conductive plastic, and the wiring pattern 420 is formed on the heat dissipation substrate 410 without any insulation treatment.

The heat dissipation fin part 440 is formed on the bottom of the heat dissipation substrate 410. The heat dissipation fin part 440 is composed of a plurality of heat dissipation fins 442, and a plurality of heat dissipation fins 442 is formed in a plate shape or a rod shape. The heat dissipation fin 442 may be formed of the same heat conductive plastic as the heat dissipation substrate 410, or may be provided by attaching another material such as aluminum to the bottom surface of the heat dissipation substrate 410. In the present embodiment, the heat dissipation fins 442 are molded together with the heat dissipation substrate 410 through a plastic molding process, and the space 444 between the heat dissipation fins 442 has an arcuate cross section.

Receiving grooves 415 are formed in the heat dissipation substrate 410. Receiving groove 415 is a space for installing the LED chip 430, the receiving groove 415 may be formed concave in order to concentrate the light generated from the LED chip 430 in one direction, specifically, a conical column Or hemispherical or the like. A wire connection method may be used to electrically connect the LED chip 430 and the wiring pattern 420. The wire protection method may be used to connect the wires to the LED chip 430 and the wiring pattern 420. It can be formed. The convex transparent protective part 435 may not only protect the wire and the LED chip 430, but may also function as a convex lens to concentrate light.

Hereinafter, with reference to the exemplary embodiments described above, a detailed description of the reason for adopting the thermally conductive plastic material in the present invention is as follows.

[Table 1] summarizes the material properties of FR4 (glass fiber reinforced epoxy) and thermally conductive plastics, which are the materials of a conventional printed circuit board (PCB). And the like. As shown in Table 1, the thermally conductive plastic has excellent thermal conductivity and low thermal expansion coefficient of about 100 times that of the general plastic (FR4), and does not need to separately form an insulating layer in the PCB structure because of excellent insulating properties. In terms of cost, printed circuit boards can be manufactured at much lower cost than metals.

Of course, the thermal conductivity is relatively lower than that of aluminum and copper, but in the heat management system, not only the thermal conductivity but also heat transfer in the form of convection and heat dissipation is mainly applied. That is, the thermal management system is determined according to three types of thermal conductivity, convection, and heat radiation.

FIG. 6 is a graph comparing the overall heat transfer coefficients of general plastics, thermally conductive plastics and aluminum in a system, and compares heat transfer coefficients by conduction and convection based on plate materials in the same condition. Where T_total is the temperature difference between the hot side of the plate and the outside atmosphere.

Referring to Figure 6, when using a general plastic having a thermal conductivity of about 0.2W / mK and a thermally conductive plastic having a thermal conductivity of about 20W / mK, it can be seen that the difference in heat transfer coefficient between the two materials is large.

However, when using a thermally conductive plastic having a thermal conductivity of about 2 W / mK and aluminum having a thermal conductivity of about 160 W / mK, it can be seen that there is almost no difference in heat transfer coefficient between the two materials. That is, even if the thermal conductivity is about 100 times the difference, it can be seen that the increase in the conductivity in the heat transfer between the thermally conductive plastic and aluminum is not very effective. This is because above the numerical value of the thermal conductivity of the thermally conductive plastic, the influence of heat transfer by convection is more important than the effect by conduction. Therefore, thermally conductive plastics can exhibit almost the same heat transfer performance as conventional aluminum. In general, if the material has a thermal conductivity of about 10 W / mK or more in a flat plate system, the overall heat transfer is limited by convection, and even if a material with thermal conductivity above this value is used, it does not improve heat transfer. .

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art may vary the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that modifications and variations can be made.

Since the light emitting device module of the present invention uses a heat-dissipating substrate made of a thermally conductive plastic instead of aluminum, it is possible to greatly reduce processing costs and raw material costs.

In addition, since the conventional plastic molding process can be used, the structure of the heat sink can be freely changed for efficient heat dissipation, and the changing process and processing are very easy.

In addition, since it has a relatively low coefficient of thermal expansion and high insulation compared to existing products, it is possible to prevent external deformation and to ensure high reliability.

In addition, since the thermally conductive plastic has almost the same heat transfer properties as conventional aluminum, aluminum can be replaced, and there is no need to form an insulating layer, which is a problem in the related art, and thus can exhibit better heat transfer characteristics than using aluminum. It may be.

Claims (14)

A substrate formed using a thermally conductive plastic; A wiring pattern formed on the substrate; And A light emitting device mounted on the substrate and electrically connected to the wiring pattern; Light emitting device module having a. The method of claim 1, The thermally conductive plastic may be acryl butadiene styrene (ABS), liquid crystal polymer (LCP), polyamide 4,6 (PA 4,6), polyphenylene sulfide (PPS), thermoplastic elastomer (TPE), thermoplastic silicone vulka Light emitting device module, characterized in that provided by using a combination of Nate (TPSiV) or a combination thereof. The method of claim 1, The substrate is a light emitting device module, characterized in that it comprises a heat radiation fin portion formed on the surface opposite to the surface on which the light emitting device is mounted. The method of claim 3, The heat dissipation fin unit includes a plurality of heat dissipation fins, wherein the heat dissipation fins are formed in a plate shape or a rod shape. The method of claim 4, wherein Light emitting device module, characterized in that provided between the radiating fins arcuate or rectangular space. The method of claim 3, The substrate is provided by injection or compression molding, wherein the heat dissipation fin portion is formed with the substrate, characterized in that the light emitting device module. The method of claim 1, The light emitting device is a light emitting device module, characterized in that the LED lamp or LED chip. A heat dissipation substrate formed using a heat conductive plastic and including a plurality of heat dissipation fins formed on a bottom surface thereof; A wiring pattern formed on the heat dissipation substrate; And A plurality of light emitting diode lamps mounted on the heat dissipation substrate and electrically connected to wiring patterns; Light emitting device module having a. The method of claim 8, The thermally conductive plastic may be acryl butadiene styrene (ABS), liquid crystal polymer (LCP), polyamide 4,6 (PA 4,6), polyphenylene sulfide (PPS), thermoplastic elastomer (TPE), thermoplastic silicone vulka Light emitting device module, characterized in that provided by using a combination of Nate (TPSiV) or a combination thereof. The method of claim 8, The heat dissipation fins are formed in a plate or rod shape, and when the heat dissipation substrate is formed by injection molding or compression molding, the heat dissipation fins are formed simultaneously with the heat dissipation substrate. A heat dissipation substrate formed using a thermally conductive plastic, the heat dissipation substrate including a plurality of receiving grooves formed on an upper surface and a plurality of heat dissipation fins formed on a bottom surface; A wiring pattern formed on the heat dissipation substrate to be adjacent to the receiving groove; And A light emitting diode chip mounted in the receiving groove and electrically connected to the wiring pattern; Light emitting device module having a The method of claim 11, The thermally conductive plastics are acrylic butadiene styrene (ABS), liquid crystalline polymer (LCP), polyamide 4,6 (PA 4,6), polyphenylene sulfide (PPS), thermoplastic elastomer (TPE), thermoplastic silicone Light emitting device module, characterized in that provided using a carbonate (TPSiV) or a combination thereof. The method of claim 11, The heat dissipation fins are formed in a plate or rod shape, and when the heat dissipation substrate is formed by injection molding or compression molding, the heat dissipation fins are formed simultaneously with the heat dissipation substrate. The method of claim 11, The receiving groove is formed with a transparent protective part made of a transparent resin, the light emitting device module, characterized in that the upper surface of the transparent protective part is provided in a convex lens shape.

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