Abstract:
This disclosure relates to a multi-piece shield comprising a fence, a lid, and an insert. The lid attaches to the fence, which is attached to the circuit board. The lid is a relatively thick, flexible material for supporting the insert. The lid has a recess so that the insert can be recessed into the lid to position the insert closer to the circuit for enhanced heat absorption. The insert is made of a thicker heat absorbing material than the lid, again to facilitate heat absorption. The insert can be press-fit into the recess of the lid. The lid can have a dovetail configuration to retain the insert in the lid.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 62/266,922 filed on Dec. 14, 2015, the entire disclosure of the application hereby expressly incorporated by reference. 
     
    
     BACKGROUND OF THE DISCLOSURE 
       [0002]    Field of the Disclosure 
         [0003]    The disclosure relates generally to shielding elements, and more particularly to a multi-piece shield for circuitry on a circuit board. 
         [0004]    Related Art 
         [0005]    Shielding elements are used in electrical circuits to protect specific components of the circuit from electromagnetic radiation (e.g., spurious emission or irradiation). In particular, screening or shielding elements are used to comply with EMC (electromagnetic compatibility) standards. 
         [0006]    One piece shields are typically used for thin devices where replaceable lids are not practical due to height restrictions and/or to minimize costs (e.g., compared to two piece shields). Two piece shields are generally more popular for circuit reworkability and testing, but are typically higher cost. 
       SUMMARY OF THE INVENTION 
       [0007]    A multi-piece shield for enhanced shielding is provided herein. The multi-piece shield can provide for additional thermal benefits such as increased thermal conductivity. The multi-piece shield could be a three piece shield including a fence, a lid, and an insert. The fence is configured to surround the circuit when mounted to the circuit board, and the lid attaches to the top of the fence. The lid could include a recess for receiving an insert therein. The insert could be made of a different material and/or be of a greater thickness than the lid to facilitate shielding and heat absorption. The insert could also be made of a material having a higher thermal conductivity to further facilitate heat absorption. With such an assembly, the insert can be positioned over (and proximate to) the circuit to shield the circuit (e.g., from electromagnetic radiation) and dissipate heat from the circuit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The foregoing features will be apparent from the following Detailed Description, taken in connection with the accompanying drawing(s), in which: 
           [0009]      FIG. 1  is a perspective view of an assembled multi-piece shield; 
           [0010]      FIG. 2  is an exploded view of the multi-piece shield of  FIG. 1 ; 
           [0011]      FIG. 3  is a bottom perspective view of the lid of the multi-piece shield of  FIG. 1 ; 
           [0012]      FIG. 4  is a cross-sectional view of the multi-piece shield of  FIG. 1  taken along the line  4 - 4 ; 
           [0013]      FIG. 5  is a perspective view of a second embodiment of an assembled multi-piece shield; 
           [0014]      FIG. 6  is an exploded view of the multi-piece shield of  FIG. 5 ; 
           [0015]      FIG. 7  is a bottom perspective view of the lid of the multi-piece shield of  FIG. 5 ; and 
           [0016]      FIG. 8  is a cross-sectional view of the multi-piece shield of  FIG. 5  taken along the line  8 - 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Disclosed herein is a multi-piece shield. The multi-piece shield provides improved shielding at a reduced weight by using a lid and insert of differing materials and/or thicknesses. The insert could be made of a material having a higher thermal conductivity and/or be of a greater thickness than the lid to facilitate shielding and heat absorption. As a result, the multi-piece shield provides efficient and cost effective shielding for use, reworkability, and/or testing of circuits. 
         [0018]      FIGS. 1-4  are views of a multi-piece shield  100 . More specifically,  FIG. 1  is a perspective view of an assembled multi-piece shield having a lid  120 , an insert  140 , and a fence  110 ,  FIG. 2  is an exploded view of the multi-piece shield  100  of  FIG. 1 ,  FIG. 3  is a bottom perspective view of the lid of the multi-piece shield of  FIG. 1 , and  FIG. 4  is a cross-sectional view of the multi-piece shield of  FIG. 1  taken along the line  4 - 4 . 
         [0019]    The fence  110  is configured to be attached to a circuit board about at least a portion of a circuit (e.g., circuit elements, electrical components, etc.). The fence  110  has sidewalls  112  having a top surface  114  and a bottom surface  116 . The height and/or thickness of the sidewalls  112  of the fence  110  may be any size depending on the performance requirements and/or heat dissipation requirements of the electrical components to be shielded. The sidewalls  112  of fence  110  could form an enclosure defining an interior  118  to surround the electrical components. The shape of the fence  110  depends on the shape of the electrical components to be shielded and their location on the circuit board. Accordingly, the fence  110  could be of any size and shape depending on the size, shape, and/or positioning of the electrical elements requiring shielding and/or heat dissipation. The fence  110  could be formed by stamping, milling, and/or bending. 
         [0020]    The lid  120  has a top wall  122 , an interior wall  124  at least partially defining a recess  126 , a shelf  128  having an inner edge  129  and defining an aperture  130 , and depending fingers  132  with dimples  134 . The exterior perimeter of the top wall  122  of lid  120  corresponds in size and shape to the exterior perimeter of the top wall of fence  110 . The size and shape of the interior perimeter of the top wall  122  of lid  120  could be independent of and could be different from the size and shape of the exterior perimeter of the top wall  122  of lid  120  and/or fence  110 . The interior perimeter of the top wall  122  could vary in size and/or shape from the exterior perimeter of the top wall  122  depending on performance requirements, the circuit layout, and/or manufacturing purposes. For example, an area of a circuit may be enclosed by the fence  110 , but not require heat dissipation and/or shielding (e.g., by the insert). Asymmetry between the interior perimeter and exterior perimeter of the top wall  122  could provide an engagement surface  136 , the engagement surface  136  providing an enlarged top wall surface for a robot to engage the lid  120  for automated assembly at the multi-piece shield  100  (e.g., to move, position, and/or assemble the lid  120  while minimizing the risk of accidental deformation of the lid  120 ). 
         [0021]    The interior wall  124  extends downwardly from the interior perimeter of the top wall  122  (e.g., extending perpendicularly from the top wall  122 ). The shelf  128  extends inwardly (e.g., towards a center of the lid  120 ) from a bottom of the interior wall  124  (e.g., extending perpendicularly from the interior wall  124 ). The shelf  128  could be parallel to, and offset from, the top wall  122 , and the top wall  122  and shelf  128  could be perpendicular to the interior wall  124 . Accordingly, the top surface of the shelf  128  and an inner surface of the interior wall  124  form a recess  126 . The inner edge  129  of the shelf  128  forms an aperture  130  therethrough. The recess  126  then being above the aperture  130  (and/or top surface of the shelf  128 ) but below the top surface of the top wall  122 . 
         [0022]    The plurality of depending fingers  132  extend downwardly from an exterior perimeter of the top wall  122 . Each of the depending fingers  132  could be generally rectangular in shape (or of any other shape). The number of depending fingers  132 , the spacing between each of the depending fingers  132 , and/or the dimensions (e.g., width, length, etc. of the depending fingers  132 ) could vary depending on the manufacturing preferences and/or performance requirements. As shown in  FIGS. 2-3 , each of the depending fingers  132  could have a dimple  134  (or a plurality of dimples  134 ) defined therein to attach and secure the lid  120  to the fence  110 . The dimples  134  are a convex shape on an interior surface (e.g., to frictionally engage the fence  110 ) and are concave on an exterior surface. Accordingly, the convex portion of the dimples  134  extends inwardly toward a center of the lid  120 . Each edge of the lid  120  has a plurality of depending fingers  132 . However, instead of having a plurality of depending fingers  132  at each edge, the lid  120  could have one long depending finger  132  for each edge of the top wall  122  where each long depending finger  132  could have one or more dimples  134 . 
         [0023]    The lid  120  could be manufactured from a single sheet of metal that is stamped (e.g., punched), pressed, and/or bent. For example, the lid  120  could be stamped, forming the aperture  130  and depending fingers  132 , and pressed to form the shelf  128 , and the depending fingers  132  could be bent to form their final shape. 
         [0024]    The insert  140  has a top surface  142 , a bottom surface  144  opposite the top surface  142 , and a perimeter  146 . The perimeter  146  of insert  140  corresponds in size and shape to the interior wall  124  of the lid  120 . The insert  140  could be made of any of a variety of materials depending on manufacturing and/or performance requirements. For example, the insert  140  could be made out of aluminum (e.g., for a normal circuit) or a material having a greater heat absorption characteristic (e.g., copper). The insert  140  can be of any variety of shapes depending on manufacturing and/or performance requirements and/or the portion of the circuit board (e.g., the particular electronic components) requiring shielding and/or heat absorption. The insert  140  could be made of a different and/or thicker material than the lid  120 . The insert  140  could be formed by stamping. 
         [0025]    As shown in  FIG. 4 , the lid  120  is assembled onto the fence  110  such that the exterior perimeter of the lid  120  aligns with the exterior perimeter of the fence  110 , which are substantially similar in size. As a result, as the lid  120  is assembled onto the fence  110 , the dimples  134  of the depending fingers  132  force the depending fingers  132  to bend outward slightly. This biases the depending fingers  132  inwardly so that the fingers  132  or the dimples  134  thereon frictionally engage an exterior surface of the fence  110 , thereby securing the lid  120  to the fence  110 . Alternatively, there could be recesses in the fence  110  such that the dimples  134  engage the recesses of the fence  110  to secure the lid  120  to the fence  110 . 
         [0026]    The insert  140  is positioned in the recess  126  of the lid  120 , such that the bottom surface  144  of the insert  140  contacts the top surface of the shelf  128  of the lid  120  and/or the perimeter  146  of the insert  140  contacts the interior wall  124  of the lid  120 . As such, the insert  140  could be press fit and/or interference fit into the lid  120 , and/or the bottom surface  144  of the insert  140  could rest on the shelf  128  of the lid  120 . When the insert  140  is assembled into the lid  120 , the insert  140  could be flush or offset from (e.g., above) the top wall  122  of the lid  120 . When the assembled multi-piece shield  100  is positioned over a circuit of a circuit board, the insert  140  (and lid  120 ) is positioned over and/or proximate to the electrical components providing electromagnetic shielding and facilitating heat dissipation of electrical components of the circuit. The insert  140  can be recessed from the lid  120  to be positioned closer to the circuitry being shielded. When assembled and positioned over the circuit, the insert  140  is directly exposed to the circuit (and circuit elements) through the aperture  130  of the shelf  128  of the lid  120 , which provides improved shielding and/or heat dissipation with decreased weight (e.g., due to the aperture  130  of the lid  120 ). 
         [0027]    The resulting assembly is a multi-piece shield  100  having a fence  110  mounted to the circuit board with a lid  120  attached to the top of the fence  110  and an insert  140  positioned in the recess  126  of the interior wall  124  of the lid  120 . 
         [0028]      FIGS. 5-8  are views of a multi-piece shield  200 .  FIG. 5  is a perspective view of a second embodiment of an assembled multi-piece shield,  FIG. 6  is an exploded view of the multi-piece shield of  FIG. 5 ,  FIG. 7  is a bottom perspective view of the lid of the multi-piece shield of  FIG. 5 , and  FIG. 8  is a cross-sectional view of the multi-piece shield of  FIG. 5  taken along the line  8 - 8 . The multi-piece shield  200  serves the same function in a similar way as the multi-piece shield  100  described in  FIGS. 1-4 . 
         [0029]    The fence  210  has the same function and shape as fence  110  in  FIGS. 1-4 . As described above, the fence  210  includes sidewalls  212  having a top surface  214  and a bottom surface  216 . The sidewalls  212  of fence  210  could form an enclosure defining an interior  218  to surround the electrical components. 
         [0030]    Similar to the lid  120  described above with respect to  FIGS. 1-4 , the lid  220  has a top wall  222 , an interior wall  224  at least partially defining a recess  226 , retaining tabs  227  having an inner edge  229  and defining an aperture  230 , and depending fingers  232  with dimples  234 . As described above, the exterior perimeter of the top wall  222  of lid  220  corresponds in size and shape to the exterior perimeter of the top wall of fence  210 , and the interior perimeter of the top wall  222  could vary in size and/or shape from the exterior perimeter of the top wall  222  depending on performance requirements, the circuit layout, and/or manufacturing purposes. Asymmetry between the interior perimeter and exterior perimeter of the top wall  222  could provide an engagement surface  236 , as described above. The interior wall  224  extends downwardly from the interior perimeter of the top wall  222 . The interior wall  224  could be of any length or depth to facilitate an insert  240  of various thicknesses. For this embodiment, the interior wall  224  is not necessary, but the interior wall  224  allows the insert to be flush with the top wall  222  of lid  220 . The lid  220  could be manufactured from a single sheet of metal that is stamped (e.g., punched), pressed, and/or bent. 
         [0031]    The plurality of depending fingers  232  extend downwardly from an exterior perimeter of the top wall  122 . Each of the depending fingers  232  could have a dimple  234  (or a plurality of dimples  234 ) defined therein to attach and secure the lid  220  to the fence  210 . As stated above, instead of having a plurality of depending fingers  232  at each edge, the lid  220  could have one long depending finger  232  for each edge of the top wall  222  where each long depending finger  232  could have a plurality of dimples  234 . 
         [0032]    Similar to the shelf  128  of the lid  120  described in  FIGS. 1-4 , the retaining tabs  227  engage the insert  240 . The retaining tabs  227  extend inwardly (e.g., towards a center of the lid  220 ) from a bottom of the interior wall  224  (e.g., extending perpendicularly from the interior wall  224 ). The retaining tabs  227  could be parallel to, and offset from, the top wall  222 , and the top wall  222  and retaining tabs  227  could be perpendicular to the interior wall  224 . Each of the retaining tabs  227  could be generally rectangular in shape (or of any other shape). The number of retaining tabs  227 , the spacing between each of the retaining tabs  227 , and/or the dimensions (e.g., width, length, etc. of the retaining tabs  227 ) could vary depending on the manufacturing preferences and/or performance requirements. The top surface of the retaining tabs  227  (e.g., lower than the top wall  222 ) and an inner surface of the interior wall  224  form a recess  226 . The inner edge  229  of the retaining tabs  227  forms an aperture  230  therethrough. The recess  226  then being above the aperture  230  (and/or top surface of the retaining tabs  227 ) but below the top surface of the top wall  222 . In this way the retaining tabs  227  increase the surface area of the inner edge  229  for better engagement with the exterior edge of the perimeter wall  246  of the insert  240 . 
         [0033]    As described above in  FIGS. 1-4 , the insert  240  has a top surface  242 , a bottom surface  244  opposite the top surface  242 , and a perimeter wall  246 . The perimeter wall  246  of insert  240  corresponds in size and shape to the interior edge  229  of the retaining tabs  227 . 
         [0034]    As shown in  FIG. 8 , the lid  220  is assembled onto the fence  210 , as described above in  FIGS. 1-4 . 
         [0035]    The insert  240  is positioned in the aperture  230  (and could also be positioned in at least a portion of the recess  226 ), such that the perimeter wall  246  (e.g., exterior edge) of the insert  240  contacts the inner edge  229  of the retaining tabs  227  of the lid  220 . As such, the insert  240  could be press fit and/or interference fit into the lid  220 . The retaining tabs  227  formation increases the contact surface between the lid  220  and the insert  240  to better secure the insert  240  to the lid  220 . When the assembled multi-piece shield  200  is positioned over a circuit of a circuit board, the insert  240  (and lid  220 ) is positioned over and/or proximate to the electrical components providing electromagnetic shielding and facilitating heat dissipation of electrical components of the circuit. When assembled and positioned over the circuit, the insert  240  is directly exposed to the circuit (and circuit elements) through the aperture  230  of the retaining tabs  227  of the lid  120 , which provides improved shielding and/or heat dissipation with decreased weight (e.g., due to the aperture  230  of the lid  220 ). 
         [0036]    The resulting assembly is a multi-piece shield  200  having a fence  210  mounted to the circuit board with a lid  220  attached to the top of the fence  210  and an insert  240  positioned in the aperture  230  of the interior wall  224  of the lid  220 . 
         [0037]    The multi-piece shield  200  described in  FIGS. 5-8  could have a thinner profile than the multi-piece shield  100  described in  FIGS. 1-4  because the insert  240  of the multi-piece shield  200  is positioned within the aperture  230  formed by the retaining tabs  227 , rather than positioning the insert  140  on top of the shelf  128  as in the multi-piece shield  100 . Thus, the multi-piece shield  200  could be thinner than the multi-piece shield  100  by at least the thickness of the lid  120  (e.g., the shelf  128 ). Also, in  FIGS. 5-8 , more surface area of the insert  240  could be exposed to the circuit as the retaining tabs  227  do not overlap any of the insert  240  (e.g., as in multi-piece shield  100  where the shelf  128  overlaps with the insert  140 ). 
         [0038]    The present disclosure may be embodied in other specific forms without departing from the spirit or essential attributes of the disclosure. 
         [0039]    Having thus described the disclosure in detail, it is to be understood that the foregoing description is not intended to limit the spirit or scope thereof. It will be understood that the embodiments of the present disclosure described herein are merely exemplary and that a person skilled in the art may make any variations and modification without departing from the spirit and scope of the disclosure. All such variations and modifications, including those discussed above, are intended to be included within the scope of the disclosure.