Abstract:
A light powered barrier for cooling a substrate includes a thermo-conductive layer for contacting the substrate, a first P-type layer disposed atop the thermo-conductive layer, a first N-type layer disposed over the first P-type layer and a thermoelectrically conductive insert that conducts heat from the thermo-conductive layer and electrically conducts electrons and holes from the first P-type layer and the first N-type layer.

Description:
BACKGROUND 
       [0001]    Thin film light cells, which are also called thin film photovoltaic cells, are light cells that are made by depositing one or more thin layers of a P-type material upon one or more layers of an N-type material. An electric current is created when light hits the materials as electrons and/or electron holes flow from the N-type material to P-type material. This flow may be tapped and used for various applications. 
         [0002]    Peltier thermal electric devices are made from alternating P-type and N-type materials that are connected by metallic interconnects and have a power supply. The power supply provides a current that flows through the junctions of the materials to provide cooling or a cooling effect. Electrons in the N-type material move opposite the direction of current and holes in the P-type material move in the direction of current, both moving heat from one side of the device to the other. 
       SUMMARY 
       [0003]    According to an embodiment disclosed herein, a light powered barrier for cooling a substrate includes a thermo-conductive layer for contacting the substrate, a first P-type layer disposed atop the thermo-conductive layer, a first N-type layer disposed over the first P-type layer and a thermoelectrically conductive insert that conducts heat from the thermo-conductive layer and electrically conducts electrons and holes from the first P-type layer and the first N-type layer. 
         [0004]    According to a further embodiment disclosed herein, a method for cooling a substrate includes the steps of: providing a thermo-conductive layer for contacting a substrate to be cooled, providing a first P-type layer disposed atop the thermo-conductive layer, providing a first N-type layer disposed over the first P-type layer, providing a thermoelectrically conductive insert that conducts heat from the thermo-conductive layer and electrically conducts electrons and holes between the first P-type layer and the N-type layer and exposing the N-type layer to light to induce the conduction of electrons and holes from the thermo-conductive layer, the first P-type layer and the N-type layer to draw heat away from the substrate through the insert to ambient. 
         [0005]    According to a still further embodiment disclosed herein, a method for constructing a light powered barrier for cooling a substrate includes the steps of providing a thermo-conductive layer for contacting a substrate, laying a first P-type layer atop the thermo-conductive layer, laying a first N-type layer atop the first P-type layer, and placing a thermoelectrically conductive insert in close proximity to the thermo-conductive layer, the first P-type layer and the first N-type layer such that the insert conducts heat from the thermo-conductive layer and electrically conducts electrons and holes from the first P-type layer and the N-type layer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
           [0007]      FIG. 1  shows an embodiment of a thin film Peltier thermal light powered barrier cooler. 
           [0008]      FIG. 2  shows a method of constructing the bather cooler of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0009]    Referring now to  FIG. 1 , a thin film peltier thermal light powered barrier cooler  10  is shown. Such coolers  10  may be used in any application in which the back side or bottom layer  15  of the cooler  10  is desired to be cooler to cool objects  20  such as, but not limited, to space suits, roofing panels, food chillers, medicine holders, etc. 
         [0010]    Describing the material from the bottom layer  15  which is designed to be placed on an object  20  to be cooled to the top layer  25  of the cooler  10 , which is exposed to the light  30 . The bottom layer  15  may be aluminum or other thermo-conductive material. The bottom layer  15  may include a mesh overlay  35  for promoting cooling air therethrough and is covered with a plurality of spaced P-type material layers  40 , which may be silicon doped with boron, aluminum, or gallium. The P-type material layers  40  are separated by electro/thermal conductive t-shaped spacers  45 . Each T-shaped insert or spacer  45  has a vertical portion  50  and a cross portion  55  disposed atop of the vertical portion  50 . The T-shaped spacer  45  may have other shapes. 
         [0011]    An N-type material first layer  60 , such as silicon doped with phosphorus or arsenic or a cadmium disulfide or the like, is disposed in between the cross portions  55  and on top of and contacting the P-type material layer  40 , and a second layer  70  of an N-type material overlays the first layer  60  of N-type material and the cross portion  55  of the t-shaped spacer  45 . 
         [0012]    If light strikes the cooler  10 , holes (not shown) flow in a direction of current indicated by arrows  75  and  80  and electrons (not shown) flow in an opposite direction of the arrows  75  and  80  such that heat indicated by arrows  85  is induced to flow from the bottom layer  15  through the vertical portion  50  to the cross portion  55  and therefrom through the second layer  70  of N-type material to ambient as shown by arrows  90  thereby cooling bottom layer  15  and object  20 . 
         [0013]    By combining a thin film light type power device with a Peltier-effect device, a light-powered cooler  10  is created that has very little cost to run. In a more typical arrangement, the bottom layer of aluminum in a cooling application requires a heat sink and fins (not shown). In this application, fins and sinks (not shown) may be minimized if not eliminated. 
         [0014]    Referring to  FIG. 2 , the process of creating the thin film peltier thermal light power barrier cooler  10  is described. The bottom layer  15  of thermo-conductive material is provided (step  100 ). A P-type material layer  40  is silk screened onto the bottom layer  15  (step  105 ). T-shaped spacers  45  may be placed between the layers P-type material layers  40  such that the cross portion  55  of each spacer  45  is in contact with a top  95  of two of the adjacent P-type material layers  40  and the vertical portion  50  is in contact with the cross portion  55 , the bottom layer  15  and each adjacent P-type material layer  40  (step  110 ). The first layer  60  of N-type material is silk screened between the cross portions  55  of the t-shaped spacers  45  (step  115 ). After placing the N-type material between the cross portions  55 , the N-type material second layer  70  is disposed atop the first layer  60  of N-type material and the cross portions  55  to build to the desired level (step  120 ). As an alternative, steps  115  and  120  may be combined to deposit the first and second layers  60 ,  70  as one thicker layer. Other methods of laying N-type material and P-type material upon the bottom layer  15  such as photographic and chemical processing (not shown) or the like are contemplated herein. 
         [0015]    Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
         [0016]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.