Abstract:
A heat sink for an electronic component includes a base having a width. The base has a greater thickness at a middle portion along the width than at opposite end portions along the width. A plurality of elongate fins project from an upper surface of the base and extend in directions perpendicular to the upper surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/063,021, filed on Oct. 13, 2014, which the disclosure of which is hereby incorporated by reference in its entirety for all purposes. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention. 
         [0003]    The present invention relates to a heat sink, and, more particularly, to a heat sink for dissipating heat from a microprocessor or similar device. 
         [0004]    2. Description of the Related Art. 
         [0005]    Heat sinks are known to physically engage and carry heat away from electronic components that otherwise may be damaged by the heat. The heat sink typically is made of aluminum and has a base with a surface that contacts the electronic component. The heat sink also typically has a series of fins extending from the base in a direction away from the electronic component. The fins provide a large surface area within a limited three-dimensional space to thereby increase the rate of convection of heat from the heat sink to the air. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention may provide a heat sink for use under natural convection conditions and with surface mount devices. The outer side of the base of the heat sink has a convex shape, and the base is thicker at the middle of the base than at the ends of the base. Thus, the heat sink has a higher capacity to carry away heat from the middle of the printed circuit board, where the board is hottest. The fins may fan out away from the base of the heat sink due to the convex external surface of the base. That is, the distance between adjacent fins increases along the heights of the fins. The increased distance between adjacent fins may enable the fins to have greater thicknesses. Thus, the heat sink may have higher heat capacity as compared to the equivalent envelope of a traditional heat sink. 
         [0007]    The heat sink may include fins in the middle of the heat sink of greater thickness than the fins on the ends of the heat sink. The thickness of the fins in the middle of the heat sink may be tapered such that the fins become progressively thinner towards the distal ends thereof. 
         [0008]    The heat sink may include trenches of semi-circular cross section on the upper surface of the base between the fins. Each trench may be disposed between a respective pair of the fins. The trenches increase the surface area on the upper surface of the base thereby increasing the heat dissipating capacity of the heat sink. 
         [0009]    The heat sink may enable the design of an external audio amplifier that is less than 40 millimeters in overall height and dissipates 15 W of heat (Class I) version). 
         [0010]    The invention comprises, in one form thereof, a heat sink for an electronic component, including a base having a width. The base has a greater thickness at a middle portion along the width than at opposite end portions along the width. A plurality of elongate fins project from an upper surface of the base and extend in directions perpendicular to the upper surface. 
         [0011]    The invention comprises, in another form thereof, a heat sink for an electronic component, including a base having a convexly shaped surface. A plurality of elongate fins project from the surface of the base and extend in directions perpendicular to the surface. 
         [0012]    The invention comprises, in another form thereof, a heat sink for an electronic component, including a base having a surface. A plurality of substantially parallel channels are disposed in the surface. A plurality of elongate fins project from the surface of the base and extend in directions perpendicular to the surface and parallel to the channels. Each fin is disposed between two adjacent channels. 
         [0013]    An advantage of the present invention is that it may provide increased heat dissipation when compared to traditional heat sinks both under natural convection conditions and under forced air conditions. 
         [0014]    Another advantage of the present invention is that the entire surface of the heat sink may be utilized for heat dissipation. Thus, a smaller package is enabled with shorter fins. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above-mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0016]      FIG. 1 a    is a top perspective view of one embodiment of a heat sink of the present invention. 
           [0017]      FIG. 1 b    is another top perspective view of the heat sink of  FIG. 1   a.    
           [0018]      FIG. 2 a    is a front view of the heat sink of  FIG. 1   a.    
           [0019]      FIG. 2 b    is another front view of the heat sink of  FIG. 1   a.    
           [0020]      FIG. 2 c    is an enlarged view of the circular area A in  FIG. 2   b.    
           [0021]      FIG. 3 a    is a bottom perspective view of the heat sink of  FIG. 1   a.    
           [0022]      FIG. 3 b    is another bottom perspective view of the heat sink of  FIG. 1   a.    
           [0023]      FIG. 4 a    is a bottom view of the heat sink of  FIG. 1   a.    
           [0024]      FIG. 4 b    is another bottom view of the heat sink of  FIG. 1   a.    
           [0025]      FIG. 5  is a side view of the heat sink of  FIG. 1   a.    
           [0026]      FIG. 6  is a top perspective view of the heat sink of  FIG. 1 a    attached to an electronic component. 
           [0027]      FIG. 7 a    is a top perspective view of another embodiment of a heat sink of the present invention. 
           [0028]      FIG. 7 b    is another top perspective view of the heat sink of  FIG. 7   a.    
           [0029]      FIG. 8 a    is a front view of the heat sink of  FIG. 7   a.    
           [0030]      FIG. 8 b    is another front view of the heat sink of  FIG. 7   a.    
           [0031]      FIG. 9 a    is a bottom perspective view of the heat sink of  FIG. 7   a.    
           [0032]      FIG. 9 b    is another bottom perspective view of the heat sink of  FIG. 7   a.    
           [0033]      FIG. 10 a    is a bottom view of the heat sink of  FIG. 7   a.    
           [0034]      FIG. 10 b    is another bottom view of the heat sink of  FIG. 7   a.    
           [0035]      FIG. 11  is a side view of the heat sink of  FIG. 7   a.    
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Glossary 
         [0037]    Fins—standing ridges on an ordinarily hot object, such as a heat sink, a radiator, etc., intended to increase heat transfer to the surrounding air by exposing a large surface area. 
         [0038]    Channels—long, narrow cuts or indentations in a surface. 
         [0039]    The embodiments hereinafter disclosed are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following description. Rather the embodiments are chosen and described so that others skilled in the art may utilize its teachings. 
         [0040]      FIG. 1 a - b    are perspective views of one embodiment of a heat sink  10  of the present invention, including a rectangular base  12  and sixteen rectangular fins  14   a - p  extending from an upper convex surface  16  of base  12 . Fins  14   a - g  and  14   j - p  may be substantially planar. Heat sink  10  may include two elongate flanges  17   a - b  on opposite sides thereof. Flanges  17   a - b  may include throughholes, such as throughholes  19   a - h,  through which heat sink  10  may be secured to a heat generating electronic component. Heat sink  10  may be formed of extruded aluminum, or some other material that is a good conductor of heat. 
         [0041]    Base  12  may have a width  18  ( FIG. 2 a   ) of approximately between 80 and 100 millimeters, a length  20  ( FIG. 4 a   ) of approximately between 110 and 135 millimeters. A height  22  of heat sink  10  may be approximately between 12 and 25 millimeters. Each of fins  14   a - g  and  14   j - p  may have a thickness  26  of approximately between 1.5 and 2.5 millimeters. A distance  28  between each pair of adjacent fins  14  may be approximately between 1.0 and 4.0 millimeters at the proximal ends of each fin  14 , i.e., at upper surface  16 . The upper or distal edges of fins  14   b - o  may define a substantially continuous and convex envelope  29 . 
         [0042]    As best illustrated in  FIG. 2   a,  base  12  has a tapered cross section across its width, thus providing a convex fin mounting surface  16 . The thickest portion of base  12  is in the center where a lower surface  30  is lowest. Lower surface  30  ramps upward and base  12  becomes thinner farther away from the center, providing the highest thermal conduction at the heat source. This configuration may reduce spreading resistance, and provide clearance for connector pins and the mounting of devices on a printed circuit board  32 . 
         [0043]    Fins  14   a - p  may be fanned out from each other. More particularly, fin gaps  28  may increase towards the upper ends of the fins, resulting in improved convective air flow away from fins  14   a - p.    
         [0044]    The spacing between the two innermost or middle fins  14   h - i  may be larger than the spacing  28  between other fins  14  to provide greater convective air flow at the heat source and increased heat dissipation. Middle fins  14   h - i  may have angled inner surfaces  34   a - b  which provide an increasing gap between fins  14   h - i  toward the distal ends of tins  14   h - i,  and which thereby promotes more convective air flow at the center of the heat source. 
         [0045]    Fins  14   f - k,  which may be located directly above the heat source, may have channels  36   f - j  of partially circular cross section between adjacent ones of the fins. The channels  36   f - j  of partially circular cross section may receive attachment screws from the sides, e.g., in directions into or out of the page of  FIG. 2   a.  In contrast, fins  14   a - f  and  14   k - p  may have flat surfaces between adjacent ones of the fins. Channels  36   f - g  and  36   i - j  are concave and semi-circular, and provide about 50-60% more surface area than do flat surfaces. Channel  36   h  forms about 315 degrees of a circle. 
         [0046]    A specific embodiment of a heat sink of the present invention is shown in  FIGS. 2   b,    4   b  and  5  with specific dimensions. 
         [0047]      FIG. 6  is a top perspective view of heat sink  10  attached to a heat generating electronic component  38 . A heat spreader pad (not shown) may be disposed at  40  between heat sink  10  and electronic component  38 . 
         [0048]    Another embodiment of a heat sink  110  of the present invention is shown in  FIGS. 7-11 . Heat sink  110  differs from heat sink  10  in that fins  114   a  and  114   p  are shorter than fins  14   a  and  14   p  and have respective chamfered outer corners  142   a  and  142   p  ( FIG. 8 a   ). Thus, fins  114   a  and  114   p  enable improved air flow across heat sink  110  at directions indicated by arrows  144   a  and  144   p,  which are generally at right angles to the fins. 
         [0049]    While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.