Abstract:
The invention discloses an encapsulation comprising a metal substrate, a PCB on the metal substrate, a thermo-electric element in and/or on the PCB, and an LED on the thermo-electric element. Encapsulating methods are also provided by the invention.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an encapsulation and fabrication methods thereof, and in particular to methods for integrating a thermo-electric element with a metal printed circuit board (PCB) and the resultant encapsulation.  
         [0003]     2. Description of the Related Art  
         [0004]     A thermo-electric element, also called a cooling device, utilizes active cooling techniques, while conventional fins use passive cooling techniques. Compared to conventional fins, the thermo-electric element features low noise, low pollution, long lifetime, easy set-up. Further, it is compact and can continuously work without using any cooling agents. The thermo-electric element is therefore appropriate to meet the demands of high-power electronic devices such as integrated circuits or light emitting diodes.  
         [0005]     A metal PCB is widely used by IC or light emitting diode manufactures due to the heat dissipation efficiency thereof.  
         [0006]     A light emitting diode include suffers from problems, e.g. heat dissipation, during operation, and generated heat which significantly affects luminescence and lifetime thereof. Accordingly, a method for eliminating the described problems is desirable.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     “Encapsulation” used hereinafter refers to an integrated device in which a metal printed circuit board (PCB) is integrated with a thermo-electric element.  
         [0008]     In accordance with one aspect of the invention, an encapsulation comprising a metal substrate, a PCB on the metal substrate, a thermo-electric element in and/or on the PCB, and an LED on the thermo-electric element is disclosed. In another preferred embodiment of the invention, the encapsulation further comprises an insulating layer interposed between the metal substrate and the first PCB. In another preferred embodiment of the invention, the encapsulation further comprises a dielectric layer on the first thermo-electric element, wherein the dielectric layer comprises a plurality of trenches. In yet another preferred embodiment of the invention, the encapsulation further comprises a heat dissipation module. In yet another preferred embodiment of the invention, the encapsulation further comprises a connector, a driving IC and a resistor.  
         [0009]     In accordance with another aspect of the invention, an encapsulating method is presented. The method comprises providing a PCB, wherein the PCB includes a copper layer; patterning the copper layer to form a plurality of first electrodes, and exposing a portion of the PCB surface; forming a plurality of P-type electrodes and N-type electrodes on the first electrodes; forming a plurality of second electrodes on the P-type and N-type electrodes, wherein the first electrode, the P-type electrode, the N-type electrode, and the second electrode constitute a thermo-electric element; forming a light emitting diode on the thermo-electric element; and attaching the PCB to a metal substrate by a method such as lamination or adhesion.  
         [0010]     In accordance with another aspect of the invention, an encapsulating method is presented, comprising disposing a first PCB on a second PCB, wherein the second PCB includes a copper layer sandwiched between the first PCB and the second PCB; forming a plurality of openings in the first PCB, and exposing a portion of the copper layer surface; patterning the copper layer to form a plurality of first electrodes, and exposing a portion of the second PCB surface; forming a plurality of P-type electrodes and N-type electrodes on the first electrodes; forming a plurality of second electrodes on the P-type and N-type electrodes, wherein the first electrode, the P-type electrode, the N-type electrode, and the second electrode constitute a thermo-electric element; forming a light emitting diode on the thermo-electric element; and attaching the PCB to a metal substrate by a method such as lamination or adhesion.  
         [0011]     The heat dissipation efficiency of the light emitting diode, PCB, connector, driving IC, and resistor is effectively enhanced by integrating the thermo-electric device with the metal PCB, thus, device performance is improved. For example, both luminescence and lifetime are dramatically increased. Further, the addition of an appropriate heat dissipation module can achieve advanced heat dissipation efficiency.  
         [0012]     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0014]      FIGS. 1   a ˜ 1   h  are cross sections of a fabrication method of an encapsulation in accordance with one preferred embodiment of the invention; and  
         [0015]      FIGS. 2   a ˜ 2   h  are cross sections of a fabrication method of an encapsulation in accordance with another preferred embodiment of the invention;  
         [0016]      FIGS. 3   a ˜ 3   e  are cross sections of a fabrication method of an encapsulation in accordance with another preferred embodiment of the invention;  
         [0017]      FIG. 4  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention;  
         [0018]      FIG. 5  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention;  
         [0019]      FIG. 6  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention;  
         [0020]      FIG. 7  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention;  
         [0021]      FIG. 8  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention;  
         [0022]      FIG. 9  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention; and  
         [0023]      FIG. 10  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention; 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.  
       FIRST EMBODIMENT  
       [0025]      FIGS. 1   a ˜ 1   h  are cross sections of a fabrication method of an encapsulation in accordance with one preferred embodiment of the invention  
         [0026]     As shown in  FIG. 1   a,  a PCB  100  with a copper layer  105  is provided.  
         [0027]     As shown in  FIG. 1   b,  the copper layer is patterned to form a plurality of first electrodes  105   a,  and exposing a portion of the PCB surface.  
         [0028]     As shown in  FIG. 1   c,  a plurality of P-type electrodes  115  and N-type electrodes  110  are formed on the first electrodes  105   a.  Specifically, the first electrodes  105   a  are formed using an engraving machine. In other embodiments, the first electrodes  105   a  are formed by means of a laser treatment or an etching process.  
         [0029]     As shown in  FIG. 1   d,  the PCB  100  is attached to a metal substrate  120  by a method of lamination or adhesion.  
         [0030]     As shown in  FIG. 1   e,  a plurality of second electrodes  125  are formed on the P-type electrodes  115  and N-type electrodes  110 . The first electrode  105   a,  the P-type electrode  115 , the N-type electrode  110 , and the second electrode  125  constitute a thermo-electric element.  
         [0031]     As shown in  FIG. 1   f,  an anode  130  is formed on the second electrode  125 .  
         [0032]     As shown in the  FIG. 1   g,  a light emitting layer  135  is formed on the anode  130 .  
         [0033]     As shown in the  FIG. 1   h,  a cathode  140  is formed on the light emitting layer  135 . The anode  130 , the light emitting layer  135  and the cathode  140  consist of a light emitting diode disposed on the thermo-electric element.  
         [0034]     Heat generated by the lighting of the light emitting diode is conducted by means of the underlying thermo-electric element to the environment. In other various embodiments, formation of the thermo-electric element and the light emitting diodes on the PCB can be performed prior to attachment of the BCB to the metal substrate. Attachment of the BCB to the metal substrate may be performed by means of lamination or adhesion.  
       SECOND EMBODIMENT  
       [0035]      FIGS. 2   a ˜ 2   h  are cross sections of a fabrication method of an encapsulation in accordance with another preferred embodiment of the invention.  
         [0036]     As shown in the  FIG. 2   a,  a first PCB  205  is disposed on a second PCB  200 . The second PCB  200  includes a copper layer (not shown) sandwiched between the first PCB  205  and the second PCB  200 . In addition, the first PCB  205  includes many contacts  210  and openings  212  therein, and the openings  212  expose a portion of the copper layer surface.  
         [0037]     As shown in the  FIG. 2   b,  the copper layer is patterned to form a plurality of first electrodes  215 , and expose a portion of the surface of the second PCB  20 . Specifically, the first electrodes  215  are formed using an engraving machine. In other embodiments, the first electrodes  215  are formed by means of a laser treatment or an etching process.  
         [0038]     As shown in the  FIG. 2   c,  a plurality of P-type electrodes  225  and N-type electrodes  220  are formed on the first electrodes  215 .  
         [0039]     As shown in the  FIG. 2   d,  the stacked PCBs  200 ,  205  are attached to a metal substrate  230  by means of lamination or adhesion.  
         [0040]     As shown in the  FIG. 2   e,  a plurality of second electrodes  235  are formed on the P-type electrodes  225  and N-type electrodes  220 . The first electrode  215 , the P-type electrode  225 , the N-type electrode  220 , and the second electrode  235  constitute a thermo-electric element.  
         [0041]     As shown in the  FIG. 2   f,  an anode  240  is formed on the second electrode  235 .  
         [0042]     As shown in the  FIG. 2   g,  a light emitting layer  245  is formed on the anode  240 .  
         [0043]     As shown in the  FIG. 2   h,  a cathode  250  is formed on the light emitting layer  245 . The anode  240 , the light emitting layer  245  and the cathode  250  consist of a light emitting diode disposed on the thermo-electric element.  
         [0044]     Heat generated by the lighting of the light emitting diode is conducted by means of the underlying thermo-electric element to the environment. In other various embodiments, after formation of the thermoelectric element in the PCB and formation of the light emitting diodes on the thermo-electric element, attachment of the BCB to the metal substrate is then performed. Attachment of the BCB to the metal substrate may be performed by means of lamination or adhesion.  
       THIRD EMBODIMENT  
       [0045]      FIGS. 3   a ˜ 3   e  are cross sections of a fabrication method of an encapsulation in accordance with another preferred embodiment of the invention  
         [0046]     As shown in the  FIG. 3   a,  provide a metal substrate  300 .  
         [0047]     As shown in the  FIG. 3   b,  a PCB  305  is formed on the metal substrate  300 , and a plurality of first electrodes  310  are then formed on the PCB  305  by patterning the copper layer (not shown) of the PCB  305 . Formation of the first electrodes  310  includes the use of an engraving machine. In other exemplary embodiments, the first electrodes  310  are formed utilizing a laser treatment or an etching process.  
         [0048]     As shown in the  FIG. 3   c,  a dielectric layer  315  including a plurality of openings is formed on the PCB  305 .  
         [0049]     As shown in the  FIG. 3   d,  a plurality of P-type electrodes  325  and N-type electrodes  320  are formed on the first electrodes  310 .  
         [0050]     As shown in the  FIG. 3   e,  a plurality of second electrodes  327  are formed on the P-type electrodes  325  and N-type electrodes  320 . The first electrode  310 , the P-type electrode  325 , the N-type electrode  320 , and the second electrode  327  constitute a thermo-electric element. Subsequently, a light emitting diode consisting of an anode  330 , a light emission layer  335  and a cathode  340  is disposed on each thermoelectric element.  
       FOURTH EMBODIMENT  
       [0051]      FIG. 4  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention  
         [0052]     In this embodiment, the encapsulation includes a metal substrate  400 , an insulating layer  405  on the metal substrate  400 , a metal layer  410  including openings on the insulating layer  405 , a dielectric layer  415  including the same openings on the metal layer  410 , thermo-electric devices respectively formed in each opening, and light emission diodes respectively formed in each thermo-electric device. The thermoelectric device includes a first electrode  420 , a P-type electrode  430 , an N-type electrode  425 , and a second electrode  435 . The light emission diode includes an anode  440 , a light emission layer  445  and a cathode  450 .  
       FIFTH EMBODIMENT  
       [0053]      FIG. 5  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention. This embodiment features a stacked thermo-electric device.  
         [0054]     In this embodiment, the encapsulation includes a metal substrate  500 , an insulating layer  505  on the metal substrate  500 , a first thermo-electric device on the insulating layer  505 , an insulating layer  530  on the first thermoelectric device, a metal layer  535  including the openings on the insulating layer  530 , a dielectric layer  550  including the same openings on the metal layer  535 , second thermo-electric devices respectively formed in each opening, and light emission diodes. The first thermoelectric device includes an electrode  510 , a P-type electrode  520 , an N-type electrode  515 , and an electrode  525 . The second thermo-electric device includes an electrode  545 , a P-type electrode  560 , an N-type electrode  555 , and an electrode  565 . The light emission diode includes an anode  570 , a light emission layer  575  and a cathode  580 .  
       SIXTH EMBODIMENT  
       [0055]      FIG. 6  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention. This embodiment also features a stacked thermo-electric device.  
         [0056]     In this embodiment, the encapsulation includes a metal substrate  600 , an insulating layer  605  on the metal substrate  600 , a first thermo-electric device on the insulating layer  605 , an insulating layer  630  on the first thermo-electric device, second thermo-electric devices arranged on the insulating layer  630  by a predetermined spacing, and light emission diodes on the second thermo-electric devices. The first thermoelectric device includes an electrode  610 , a P-type electrode  620 , an N-type electrode  615 , and an electrode  565 . The second thermoelectric device includes an electrode  635 , a P-type electrode  645 , an N-type electrode  640 , and an electrode  650 . The light emission diode includes an anode  655 , a light emission layer  660  and a cathode  665 .  
       SEVENTH EMBODIMENT  
       [0057]      FIG. 7  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention.  
         [0058]     In this embodiment, the encapsulation includes a metal substrate  700 , an insulating layer  705  on the metal substrate  700 , a metal layer  710  including first openings on the insulating layer  705 , thermo-electric devices respectively disposed in each first opening, a dielectric layer  735  including trenches on the metal layer  710 , light emitting diodes  740  respectively formed in each trench, lens  750 , electrodes  760 , and metal bonding  770 . Specifically, the surface of each trench is coated with a reflective film  745 . The thermo-electric device includes a first electrode  715 , a P-type electrode  725 , an N-type electrode  720 , and a second electrode  730 .  
       EIGHTH EMBODIMENT  
       [0059]      FIG. 8  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention  
         [0060]     In this embodiment, the encapsulation includes a metal substrate  800 , an insulating layer  810  on the metal substrate  800 , a metal layer  820  including openings on the insulating layer  810 , thermo-electric devices respectively disposed in each opening, light emitting diodes on the thermo-electric devices. The encapsulation also comprises a connector  875 , a driving IC  865  and a resistor  870  separately disposed on the metal layer  820 . The thermo-electric device includes a first electrode  830 , a P-type electrode  850 , an N-type electrode  840 , and a second electrode  860 . The light emission diode includes an anode  880 , a light emission layer  885  and a cathode  890 .  
       NINTH EMBODIMENT  
       [0061]      FIG. 9  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention.  
         [0062]     This embodiment connects the encapsulation presented in first, second, or other embodiments to a heat dissipation module. The heat dissipation module can be composed mainly of a heat pipe  960  and a fin  970 , and the metal substrate  900  is connected to the fin  970  through the heat pipe  960 .  
       TENTH EMBODIMENT  
       [0063]      FIG. 10  is a schematic view showing an encapsulation in accordance with another preferred embodiment of the invention.  
         [0064]     Similarly, this embodiment connects the encapsulation presented in first, second, or other embodiments to a heat dissipation module. The heat dissipation module can be composed mainly of a heat pipe  1045  and a fan system  1050 , and the metal substrate  1000  is connected to the fan system  1050  through the heat pipe  1045 .  
         [0065]     The heat dissipation efficiency of the light emitting diode, PCB, connector, driving IC, and resistor is effectively enhanced by integrating the thermo-electric device with the metal PCB, thus performance of the device is improved. For example, both luminescence and lifetime are dramatically increased. Further, the addition of an appropriate heat dissipation module can achieve advanced heat dissipation efficiency.  
         [0066]     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.