Abstract:
An LED package having an anodized insulation layer which increases heat radiation effect to prolong the lifetime LEDs and maintains high luminance and high output, and a method therefor. The LED package includes an Al substrate having a reflecting region and a light source mounted on the substrate and connected to patterned electrodes. The package also includes an anodized insulation layer formed between the patterned electrodes and the substrate and a lens covering over the light source of the substrate. The Al substrate provides superior heat radiation effect of the LED, thereby significantly increasing the lifetime and light emission efficiency of the LED.

Description:
CLAIM OF PRIORITY 
     This application claims the benefit of Korean Patent Application No. 2006-0031093 filed on Apr. 5, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a Light Emitting Diode (LED) package of high luminance and high output, which uses an LED as a light source and a method therefor. More particularly, the present invention relates to an LED package, which has a light source mounted in a reflecting region of an aluminum (Al) substrate that is anodized to have an insulation layer, thereby increasing the heat radiation effect of the LED during the light emission operation, prolonging the lifetime of the LED and maintaining high luminance and output of the LED, and to a fabrication method therefor. 
     2. Description of the Related Art 
     In general, as shown in  FIG. 1 , a conventional LED package having an LED as a light source includes an LED  215  mounted on a substrate  210  and electrically connected to power to operate and emit light. 
     In such an LED package  200 , the LED  215  generates light according to its characteristics and radiates heat at the same time. Thus, it is critical that the heat is discharged effectively to the outside to prevent overheating in order to maintain a long lifetime and good output efficiency. 
     The conventional LED package  200  includes an LED  215  mounted on a circuit substrate  210  having a fixed patterned electrode  205 , and also includes a reflecting member  220  having a roughly the same size as the exterior of the substrate  210  and a reflecting surface  222  formed therein. The reflecting member  220  is integrally fixed to the upper part of the substrate  210  by an epoxy resin, etc. 
     In such a conventional LED package  200 , a concave reflecting surface  222  is formed in the reflecting member  220 , and thus the light from the LED  215  is reflected forward by the reflecting surface  222 . 
     However, in the conventional LED package  200 , the substrate  210  is not made of a material with high heat conductivity, i.e., good heat radiation capacity, for example, aluminum (Al), and thus heat radiation is not effective during the light emission operation of the LED  215 . 
     In addition, the conventional LED package  200  needs to have the reflecting member  220  fixed by a separate process, hindering a simplified manufacturing processes. Furthermore, the rather inaccurate process of integrating the reflecting member  220  with the substrate can be a major cause of defective products, thereby increasing the assembly costs. 
     SUMMARY OF THE INVENTION 
     The present invention has been made to solve the foregoing problems of the prior art and therefore an aspect of the present invention is to provide an LED package having an anodized insulation layer, which has a superior heat radiation effect of an LED through a substrate, thereby increasing the lifetime and light emission efficiency of the LED, and a fabrication method therefor. 
     Another aspect of the invention is to provide an LED package which does not require a separate bonding process of a reflecting member to a substrate and facilitates the process of aligning a lens to the substrate, thereby reducing the manufacturing costs through a simplified manufacturing process, and a fabrication method therefor. 
     According to an aspect of the invention, the invention provides an LED package which includes: an Al substrate having a reflecting region; a light source mounted on the substrate and electrically connected to patterned electrodes of the substrate, the light source comprising an LED; an anodized insulation layer formed between the patterned electrodes and the substrate; a lens disposed over the light source of the substrate; and an Al heat radiator formed under the LED so as to enhance heat radiation capacity. 
     Preferably, the substrate has the light source disposed in the reflecting region thereof, the LED of the light source comprising blue, red and green LEDs to emit white light. 
     Preferably, the substrate has electrode connecting grooves adjacent to the reflecting region thereof, the electrode connecting grooves electrically connecting the light source to patterned electrodes with wires. 
     Preferably, the substrate has lens assembly grooves formed adjacent to the reflecting region thereof, the lens assembly grooves defining the location of the lens part, and wherein the lens has projections formed on outer surfaces thereof which are assembled into the lens assembly grooves. 
     Preferably, the anodized insulation layer is formed in the electrode connecting grooves. 
     According to another aspect of the invention, the invention provides a method for fabricating a light emitting diode package. The method includes: etching a surface of a substrate to form a reflecting region; anodizing the substrate to form an insulation layer; forming patterned electrodes on the substrate; mounting a light source on the substrate and electrically connecting the light source to the patterned electrodes; and assembling a lens onto the substrate. 
     Preferably, the step of etching a surface of a substrate includes forming electrode connecting grooves adjacent to the reflecting region of the substrate to electrically connect the light source to the patterned electrodes with wires, and forming lens assembly grooves for defining the location of the lens part on the substrate. 
     Preferably, the method further includes dicing a mother substrate into a plurality of the individual substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exploded perspective view illustrating an LED package according to the prior art; 
         FIG. 2  is an exploded perspective view illustrating an LED package having an anodized insulation layer according to the present invention; 
         FIG. 3  is a plan view illustrating the LED package having an anodized insulation layer according to the present invention; 
         FIG. 4  is a perspective view of the exterior of a lens provided in the LED package having an anodized insulation layer according to the present invention; 
         FIG. 5  is a sectional view illustrating the LED package having an anodized insulation layer according to the present invention; 
         FIG. 6  is a perspective view illustrating the LED package having an anodized insulation layer according to the present invention being separated from a mother substrate; 
         FIG. 7  is a plan view illustrating an LED package having an anodized insulation layer according to another embodiment of the present invention; 
         FIG. 8  is a sectional view illustrating the LED package according to another embodiment of the present invention cut along the A-A line of  FIG. 7 ; 
         FIG. 9  is a plan view illustrating an LED package having an anodized insulation layer according to further another embodiment of the present invention; and 
         FIG. 10  is a sectional view illustrating the LED package according to further another embodiment of the present invention cut along the line B-B of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     As shown in  FIG. 2 , an LED package  1  having an anodized insulation layer includes a substrate  10  made of an Al material. The substrate  10  is made of an Al material which is relatively low cost and easily manufactured. 
     The substrate  10  has a reflecting region  20  formed in a center thereof. The reflecting region  20  is a recessed groove formed by etching. As shown in  FIG. 3 , the reflecting region  20  is composed of a planar central reflecting area  22  where the light source  30  is mounted as described later, i.e., a die bonding reflecting area and an inclined reflecting area  24 , i.e., a reflecting surface surrounding the central reflecting area  22 . 
     In addition, electrode connecting grooves  52  connecting the electrodes of the LEDs of the light source  30  with wires  40  and lens assembly grooves  54  defining the location of the lens  70  described later are formed adjacent to the inclined reflecting area  24  of the reflecting region  20  of the substrate  10 . 
     The electrode connecting grooves  52  and the lens assembly grooves  54  are formed in shapes recessed from the surface of the substrate  10  but do not have a depth as large as the inclined reflecting area  24  of the reflecting region  20 . Preferably, the electrode connecting grooves  52  have a depth somewhat larger than that of the lens assembly grooves  54 . This structure facilitates the placement of the wires  40  in the electrode connecting grooves  52 . 
     Moreover, the electrode connecting grooves  52  and the lens assembly grooves  54  are not limited in the number in which they are provided. 
     There can be provided one or two electrode connecting grooves  52  depending on the type of LED constituting the light source  30 , and also, there can be provided a plurality of electrode connecting grooves  52  corresponding to the number of LEDs mounted on the substrate  10 . 
     In addition, the lens assembly groove  54  can be any reference grooves for easily assembling the lens  70 , and is not limited in the number provided. 
     In addition, patterned electrodes  12   a  and  12   b  are formed on the substrate  10  to supply power to the light source  30 . The patterned electrodes  12   a  and  12   b  are formed on a location on an upper surface of the substrate  10  adjacent to the reflecting region  20  and on an opposed location on a lower surface of the substrate  10 , respectively. The patterned electrodes  12   a  formed on an upper surface of the substrate  10  are for electric connection of the LED constituting the light source  30 , whereas the patterned electrodes  12   b  formed on a lower surface of the substrate  10  serve as an electric connection pad of the LED package mounted on a surface of another substrate (not shown) as a Surface Mounted Device (SMD). 
     In addition, the patterned electrodes  12   a  and  12   b  are electrically connected to each other through a plurality of vias  16  penetrating the substrate  10 . 
     The LED package  1  having an anodized insulation layer according to the present invention includes the light source  30  mounted on the substrate  10  with an LED electrically connected to the patterned electrodes  12   a  and  12   b , and anodized insulation layers  35  formed between the patterned electrodes  12   a  and the substrate  10  and between the patterned electrodes  12   b  and the substrate  10 . 
     The anodized insulation layer  35  is for insulating the patterned electrodes  12   a  and  12   b  from the substrate  10 , and is formed by locally or partially treating the substrate with Al 2 O 3  through anodizing or anodic-oxidization. 
     Such an anodized insulation layer  35  has somewhat low heat conductivity but has an excellent insulation capacity. It is formed between the patterned electrodes  12   a  and  12   b  and the substrate  10  to supply the power necessary for light emission operation of the light source  30 . 
     In the meantime, such an anodized insulation layer  35  is formed in the electrode connecting grooves  52  to be electrically insulated from the substrate  10 , but is not formed in the reflecting region  20  of the substrate  10  so as not to hinder the reflection of the light from the light source  30  to the outside. 
     In addition, the LED package  1  having an anodized insulation layer  35  includes a lens  70  covering over the light source  30  of the substrate  10 . The lens  70  has a sectional shape with an upper hemispheric shape. As shown in  FIG. 4 , the lens  70  has projections  72  formed on outer surfaces thereof, which can be inserted into the lens assembly grooves  54 . 
     These projections  72  correspond to the lens assembly grooves  54 . Such projections  72  and the lens assembly grooves  54  allow an operator to easily find the mounting location or a referential location on the substrate  10  for attaching the lens  70 . The lens  70  is adhered to the substrate  10  by a transparent adhesive resin. 
     The lens  70  adhered to the substrate  10  as described above is not disposed on the electrode connecting grooves  52  of the substrate  10 , as shown in  FIG. 5 . With the lens  70  not disposed on the electrode connecting grooves  52  as just described, the wires  40  can be placed in the electrode connecting grooves  52  and the lens  70  does not hinder the placement of the wires  40 . 
     A fabrication method of the LED package  1  having an anodized insulation layer according to the present invention entails the following steps. 
     The method of fabricating the LED package  1  having an anodized insulation layer according to the present invention starts with etching an outer surface of the substrate  10  to form a reflecting region  20 . 
     The reflecting region  20  includes a central reflecting area  22  where the light source  30  is mounted and an inclined reflecting area  24  surrounding the central reflecting area  22 . The step of forming a reflecting region  20  includes forming electrode connecting grooves  52  connecting the electrode of the LED with wires  40 , and lens assembly grooves  54  allowing convenient setting of the location of the lens  70  and easy fixing of the lens  70 , adjacent to the inclined reflecting area  24  of the reflecting region  20 . 
     Both of these electrode connecting grooves  52  and the lens assembly grooves  54  can be formed by etching. 
     Next, the substrate  10  is anodized to form insulation layer  35 . In this case, the substrate  10  is anodized on surfaces thereof except on the surface of the reflecting region  20  to form the insulation layers  35  of Al 2 O 3  on upper and lower surfaces of the substrate  10 . 
     In particular, the insulation layers  35  are formed in the electrode connecting grooves  52  and the lens assembly grooves  54  so as to ensure electric connection between the patterned electrodes  12   a  and  12   b  with the light source  30 . 
     Then, the patterned electrodes  12   a  and  12   b  are formed on the substrate  10 . The electrodes  12   a  and  12   b  are patterned on the substrate  10  in accordance with the type of LED constituting the light source  30 , whether it is a horizontal type where the LED has both electrodes connected to the wires  40  from an upper surface thereof or whether it is a vertical type where the LED has an upper electrode connected to the wire from an upper surface thereof and a lower electrode placed at the underside thereof. 
     After forming the patterned electrodes  12   a  and  12   b  as described above, the light source  30  is mounted on the substrate  10  and electrically connected to the patterned electrodes  12   a  and  12   b.    
     This step is to establish electric connection via the wires  40 . 
     After the electric connection of the light source  30  with the patterned electrodes  12   a  and  12   b , a lens  70  is assembled onto the substrate  10 . In this step, a transparent adhesive resin is applied on the reflecting region  20  of the substrate  10  and then the lens  70  is attached to the substrate  10 . 
     In this step, the projections  72  formed on the outer circumferential surface of the lens  70  are aligned with the lens assembly grooves  54  provided in the substrate  10 , and the lens  70  is easily attached to the substrate  10  using an adhesive resin. 
     In the present invention, it is possible to fabricate each of the substrate  10  and the lens  70  separately, but alternatively as shown in  FIG. 6 , the substrates  10  can be diced from a large mother substrate  80 . 
     That is, after a large mother substrate  80  is divided into a plurality of substrates  10 , the above steps are implemented on each of the substrates  10 , and then a plurality of lenses  70  are respectively attached to the substrates  10 . Then, the substrates  10  with the lenses  70  are diced into individual LED packages  1  according to the present invention. 
     The process of using such a mother substrate  80  to produce a plurality of LED packages  1  at once is well known in the art, and thus no further explanation is provided. 
     In the LED package  1  having an anodized insulation layer fabricated through the above described steps according to the present invention, the substrate  10  is made of an Al material. Such an Al substrate  10  has superior heat conductivity, allowing an excellent radiation effect of heat generated during the light emission of the LED. 
     Moreover, as the reflecting region  20  is formed in the substrate  10  by etching, and the lens  70  is easily attached to the substrate  10 , the manufacturing process is simplified to obtain a low cost LED package. 
       FIGS. 7 and 8  illustrate an LED package  1 ′ having an anodized insulation layer according to another embodiment of the present invention. 
     The LED package  1 ′ employing an anodized insulation layer according to the present invention, shown in  FIG. 8 , has a configuration and technical concept similar to those of the aforedescribed LED package  1  with reference to  FIGS. 2 to 6 . Thus, the same reference numerals will be used to designate the same components, with a prime next to each of the numbers. 
     The LED package  1 ′ employing an anodized insulation layer shown in  FIGS. 7 and 8  includes a plurality of LEDs, i.e., blue, red and green LEDs, as a light source  30 ′ to emit white light. 
     The LEDs are insulated by the anodized insulation layers  35 ′ and electrically connected by wires  40 ′ to positive (+) or negative (−) electric terminals of the patterned electrodes  12   a ′ and  12   b′.    
     In addition, the LED package  1 ′ also includes Al heat radiators  65 ′ serving as heat slugs under the LEDs to allow superior heat radiation effects. The Al heat radiators  65 ′ functioning as the heat slugs are surrounded by the anodized insulation layer  35 ′ to form electric insulation with other parts of the substrate  10 ′. Made of Al material having superior heat conductivity, the Al heat radiators  65 ′ can achieve excellent heat radiation effects. 
     Moreover, the LED package  1 ′ also has the insulation layers  35 ′ formed in the electrode connecting grooves  52 ′ and the lens assembly grooves  54 ′ so as to ensure electric connection between the patterned electrodes  12   a ′ and  12   b ′ and the light source  30 ′. 
       FIGS. 9 and 10  illustrate an LED package  1 ″ having an anodized insulation layer according to further another embodiment of the present invention. 
     This structure is similar to that of the LED package  1  with reference to  FIGS. 2 to 6 , and is based on the same technical concept. Thus, the same reference numerals are used to designate the same components, with double primes ″ next to each of the numbers. 
     The LED package  1 ″ having an anodized insulation layer according to the present invention, shown in  FIGS. 9 and 10 , includes a plurality of LEDs, i.e., blue, red and green LEDs to emit white light. The LEDs are insulated by the anodized insulation layers  35 ″ on the substrate  10 ″, and electrically connected by wires  40 ″ to positive or negative electric terminals of the patterned electrodes  12   a ″ and  12   b″.    
     The LED package  1 ″ also includes Al heat radiators  65 ″ formed under the plurality of LEDs to obtain superior heat radiation effects. The Al heat radiators  65 ″ functioning as the heat slug parts are made of an Al material of superior heat conductivity, thereby achieving excellent heat radiation effects of the LEDs. 
     In addition, the LED package  1 ″ also has the insulation layer  35 ″ formed in the electrode connecting grooves  52 ″ and the lens assembly grooves  54 ″ to ensure electric connection between the patterned electrodes  12   a ″ and  12   b ″ with the light source  30 ″. 
     According to the present invention set forth above, a substrate is made of an Al material to achieve superior heat radiation effect of LED, thereby increasing the lifetime and light emission efficiency of the LED. 
     Moreover, as a reflecting region is recessed in a substrate, there is no need to bond a separate reflecting member as in the prior art, thereby simplifying the manufacturing process. 
     Furthermore, a lens has projections thereof assembled into lens assembly grooves provided in the substrate, thereby easily determining the mounting location of the lens. This enables an easy alignment of the lens with the substrate, thereby reducing the manufacturing costs. 
     While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.