Abstract:
A heat sink for an electronic component includes a plurality of substantially planar fins extending from a base. At least two adjacent ones of the fins define an angle therebetween of greater than five degrees.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a heat sink, and, more particularly, to a heat sink for dissipating heat from a microprocessor or similar device. 
         [0003]    2. Description of the Related Art 
         [0004]    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 
       [0005]    The invention may provide a heat sink wherein the fins fan out away from the large heater spreader at the base of the heat sink. 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. 
         [0006]    In one embodiment, the heat sink is assembled to an electromagnetic interference (EMI) shield. However, assembly methods are possible within the scope of the invention. 
         [0007]    The invention comprises, in one form thereof, a heat sink for an electronic component, including a plurality of substantially planar fins extending from a base. At least two adjacent ones of the fins define an angle therebetween of greater than five degrees. 
         [0008]    The invention comprises, in another form thereof, a heat sink for an electronic component, including a base having a substantially planar first surface and a substantially planar second surface. A plurality of substantially planar fins extend from the second surface of the base. At least two adjacent ones of the fins define an angle therebetween of greater than five degrees. Each fin includes a respective distal edge. The distal edges may or may not be substantially coplanar. 
         [0009]    The invention comprises, in yet another form thereof, a heat sink assembly for an electronic component including a heat sink having a plurality of substantially planar fins extending from a base. At least two adjacent ones of the fins define an angle therebetween of greater than five degrees. An electro-magnetic interference shield includes a throughhole sized to receive the heat sink therein. At least one clip retains the heat sink within the throughhole of the shield. 
         [0010]    An advantage of the present invention is that it may provide increased heat dissipation when compared to traditional parallel fin heat sinks both under natural convection conditions and under forced air conditions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    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: 
           [0012]      FIG. 1  is a perspective view of one embodiment of a heat sink of the present invention. 
           [0013]      FIG. 2  is a front view of the heat sink of  FIG. 1 . 
           [0014]      FIG. 3  is a perspective view of another embodiment of a heat sink of the present invention. 
           [0015]      FIG. 4  is a front view of the heat sink of  FIG. 3 . 
           [0016]      FIG. 5  is a top perspective view of the heat sink of  FIG. 3  attached to an EMI shield. 
           [0017]      FIG. 6  is a bottom perspective view of the heat sink of  FIG. 3  attached to an EMI shield. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    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. 
         [0019]      FIG. 1  is a perspective view of one embodiment of a heat sink  10  of the present invention, including a substantially planar and rectangular base  12  and ten substantially planar and rectangular fins  14   a - j  extending from an upper surface  16  of base  12 . Heat sink  10  may be formed of extruded aluminum, or some other material that is a good conductor of heat. Base  12  may have a length  18  of approximately between 36.0 and 46.0 millimeters, a width  20  of approximately between 20.0 and 26.0 millimeters, and a height  22  ( FIG. 2 ) of approximately between 2.0 and 3.0 millimeters. A height  24  of heat sink  10  may be approximately between 10.0 and 14.0 millimeters. Each fin  14  may have a thickness  26  of approximately between 1.2 and 1.4 millimeters. A distance  28  between each pair of adjacent fins  14  may be approximately between 2.0 and 2.4 millimeters at the proximal ends of each fin  14 , i.e., at upper surface  16 . The upper or distal edges of fins  14   a - j  may be substantially co-planar. 
         [0020]    As best illustrated in  FIG. 2 , the two innermost or middle fins  14   e - f  are both substantially perpendicular to upper surface  16  and parallel to each other, separated from each other by distance  28 , i.e., approximately between 2.0 and 2.4 millimeters, along their entire heights. However, it the particular embodiment of  FIG. 2 , none of fins  14   a - e  are parallel to each other. Rather, fins  14   a - e  are fanned out from each other. More particularly, an angle θ 1  between fin  14   d  and a plane  30  perpendicular to the page of  FIG. 2  and bisecting heat sink  10  is approximately between eight and twelve degrees; an angle θ 2  between fin  14   c  and plane  30  is approximately between eighteen and twenty-two degrees; an angle θ 3  between fin  14   b  and plane  30  is approximately between twenty-eight and thirty-two degrees; and an angle θ 4  between fin  14   a  and a plane  30  is approximately between thirty-eight and forty-two degrees. Accordingly, an angle between fins  14   a  and  14   b  is approximately between eight and twelve degrees; an angle between fins  14   b  and  14   c  is approximately between eight and twelve degrees; and an angle between fins  14   c  and  14   d  is approximately between eight and twelve degrees. 
         [0021]    All of the angles θ 1 , θ 2 , θ 3  and θ 4  may be defined relative to a common vertex  31 . Thus, each of substantially planar fins  14   a - e  may be co-axial, with an axis that is coincident with vertex  31 . 
         [0022]    Heat sink  10  may be a minor image of itself about plane  30  such that none of fins  14   f - i  are parallel to each other. Rather, fins  14   f - j  are fanned out from each other. More particularly, an angle between fins  14   f  and  14   g  is approximately between eight and twelve degrees; an angle between fins  14   f  and  14   h  is approximately between eighteen and twenty-two degrees; an angle between fins  14   f  and  14   i  is approximately between twenty-eight and thirty-two degrees; and an angle between fins  14   f  and  14   j  is approximately between thirty-eight and forty-two degrees. Accordingly, an angle between fins  14   g  and  14   h  is approximately between eight and twelve degrees; an angle between fins  14   h  and  14   i  is approximately between eight and twelve degrees; and an angle between fins  14   i  and  14   j  is approximately between eight and twelve degrees. An angle defined between fins  14   a  and  14   j  may be approximately between seventy-six and eighty-four degrees. Thus, respective angles defined between plane  30  and each of fins  14   a - j  increases with a distance of the fin from plane  30 . 
         [0023]    All of the angles between fins  14   f - j  may be defined relative to a common vertex  33 . Thus, each of substantially planar fins  14   f - j  may be co-axial, with an axis that is coincident with vertex  33 . 
         [0024]    Fins  14   a - e  have been described above as defining angles having a common vertex  31 , and fins  14   f - i  have been described above as defining angles having a common vertex  33 . However, it is also possible within the scope of the invention for at least two of the angles defined by fins  14   a - e  to not have a common vertex, and/or for at least two of the angles defined by fins  14   f - j  to not have a common vertex. 
         [0025]      FIG. 3  is a perspective view of one embodiment of a heat sink  310  of the present invention, including a substantially planar and trapezoidal base  312  and eight substantially planar and rectangular fins  314   a - h  extending from an upper surface  316  of base  312 . Two substantially planar and rectangular wings  317   a - b  extend laterally from upper portions of opposite ends of base  312 . Heat sink  310  may be formed of extruded aluminum, or some other material that is a good conductor of heat. A lower surface  319  of base  312  may have a length  318  of approximately between 20.0 and 30.0 millimeters, and a width  320  of approximately between 20.0 and 30.0 millimeters. Base  312  has a height  322  ( FIG. 4 ) of approximately between 6.25 and 11.25 millimeters. Wings  317   a - b  have a height  323  of approximately between 2.00 and 3.00 millimeters. A height  324  of heat sink  310  may be approximately between 6.25 and 11.25 millimeters. A width  325  of heat sink  310  may be approximately between 33.0 and 42.0 millimeters. A distance  327  between upper surface  326  and a lower surface of base  312  may be approximately between 3.0 and 4.0 millimeters. Each fin  314  may have a thickness  326  of approximately between 1.2 and 1.4 millimeters. A distance  328  between each pair of adjacent fins  314  may be approximately between 1.8 and 2.2 millimeters at the proximal ends of each fin  314 , i.e., at upper surface  316 . The upper or distal edges of fins  314   a - h  may be substantially co-planar. 
         [0026]    As best illustrated in  FIG. 4 , the two innermost or middle fins  314   d - e  are both substantially perpendicular to upper surface  316  and parallel to each other, separated from each other by distance  328 , i.e., approximately between 1.8 and 2.2 millimeters, along their entire heights. However, it the particular embodiment of  FIG. 4 , none of fins  314   a - d  are parallel to each other. Rather, fins  314   a - d  are fanned out from each other. More particularly, an angle θ 1  between fin  14   c  and a plane  330  perpendicular to the page of  FIG. 4  and bisecting heat sink  310  is approximately between eight and twelve degrees; an angle θ 2  between fin  314   b  and plane  330  is approximately between eighteen and twenty-two degrees; an angle θ 3  between fin  314   a  and plane  330  is approximately between twenty-eight and thirty-two degree. Accordingly, an angle between fins  14   a  and  14   b  is approximately between eight and twelve degrees; and an angle between fins  14   b  and  14   c  is approximately between eight and twelve degrees. 
         [0027]    Heat sink  310  may be a minor image of itself about plane  330  such that none of fins  314   e - h  are parallel to each other. Rather, fins  314   e - h  are fanned out from each other. More particularly, an angle between fins  314   e  and  314   f  is approximately between eight and twelve degrees; an angle between fins  314   e  and  314   g  is approximately between eighteen and twenty-two degrees; and an angle between fins  314   e  and  314   h  is approximately between twenty-eight and thirty-two degrees. Accordingly, an angle between fins  14   f  and  14   g  is approximately between eight and twelve degrees; and an angle between fins  14   g  and  14   h  is approximately between eight and twelve degrees. An angle defined between fins  314   a  and  314   h  may be approximately between fifty-six and sixty-four degrees. Thus, respective angles defined between plane  330  and each of fins  314   a - h  increases with a distance of the fin from plane  330 . 
         [0028]    Fins  314   a - d  may define angles having a common vertex (not shown in  FIG. 4 ). Thus, each of substantially planar fins  314   a - d  may be co-axial, with an axis that is coincident with the common vertex. However, it is also possible within the scope of the invention for at least two of the angles defined by fins  314   a - d  to not have a common vertex. 
         [0029]    Fins  314   e - h  may define angles having a common vertex (not shown in  FIG. 4 ). Thus, each of substantially planar fins  314   e - h  may be co-axial, with an axis that is coincident with the common vertex. However, it is also possible within the scope of the invention for at least two of the angles defined by fins  314   e - h  to not have a common vertex. 
         [0030]      FIG. 5  is a top perspective view of a heat sink assembly  308  including a heat sink  310  attached to an electro-magnetic interference (EMI) shield  332 . Shield  332  may include clips  334   a - g  which attach heat sink  310  to a substantially planar body  336  of shield  332 . Shield  332  includes a plurality of throughholes  338  which allow air to pass between the two opposite sides of body  336 . 
         [0031]      FIG. 6  is a bottom perspective view of heat sink assembly  308  including heat sink  310  attached to EMI shield  332 . Shield  332  includes two tabs  340   a - b  which retain opposite corners of wing  317   a . Shield  332  includes another two tabs  340   c - d  which retain opposite corners of wing  317   b . Shield  332  includes a larger, substantially rectangular throughhole  341  sized to snugly receive heat sink  310  therein. 
         [0032]    Tabs  340   a - d  may be disposed at the respective four corners of throughhole  341 . Tabs  340   a - d  may engage respective edge portions of heat sink  310 . More particularly, in the specific embodiment of  FIG. 6 , tabs  340   a - d  may each engage a respective corner of wings  317   a - b.    
         [0033]    Bottom, external surface  319  of heat sink  310  may be substantially flush or co-planar with a bottom, surrounding surface  342  of body  336  of shield  332 . Bottom surface  319  of heat sink  310  may also be substantially flush or co-planar with a bottom or exposed surface of tabs  340   a - d . It is also possible for bottom surface  319  of heat sink  310  to extend slightly (e.g., 1 millimeter or more) beyond bottom surface  342  of body  336  of shield  332  and/or the bottom or exposed surface of tabs  340   a - d . Thus, bottom surface  319  of heat sink  310  may easily contact or engage the upper surface of an integrated circuit package that heat sink  310  is to carry heat away from. 
         [0034]    Ramped surfaces  342   a - b  ( FIG. 6 ) of heat sink  310  interconnect bottom surface  319  and wings  317   a - b , respectively. Ramped surfaces  342   a - b  may provide edges  346   a - b  of bottom surface  319  with obtuse angles, rather than sharper angles that could possibly damage the electronic components that bottom surface  319  is to contact or engage. 
         [0035]    During assembly, heat sink  310  may be moved into contact with shield  332  by moving heat sink  310  in direction  348  ( FIG. 5 ) until wings  317   a - b  engage tabs  340   a - d . Then, clips  334   a - g  may be inserted into shield  332  in order to securely retain heat sink  310  within throughhole  341  and in engagement with shield  332 . 
         [0036]    In order to increase the surface area of the fins, and thereby increase the heat dissipation of the heat sink, the surface of the fins may be scalloped in one embodiment (not shown). That is, the fins may include grooves or ribs extending in the direction of the heights of the fins, and the grooves or ribs may increase the surface area of the fins. 
         [0037]    Examples of specific angles between fins have been illustrated herein. However, it is to be understood that other angles are possible within the scope of the invention, and angles between fins can be optimized for specific applications. 
         [0038]    Any of the embodiments described above may be in the form of a thick fin design heat sink for higher heat sinking capacity. However, it is to be understood that the thickness of the fins and the spacing between the fins may vary. Moreover, the heights of the fins may vary depending on the desired heat dissipation characteristics and packaging restraints. The fins can have a natural finish, or may have an anodized black finish for increased heat dissipation. 
         [0039]    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.