PATENT DOCUMENT

Publication Number: US-8879269-B2
Application Number: US-201113222144-A
Country: US
Kind Code: B2

Title: Systems and method for providing a graphite layer in an electronic device

Abstract:
Systems and methods are provided for a sheet of graphite material on an electromagnetic interference shield for enhanced heat transfer. An electronic device component may be enclosed by an EMI shield, which may retain heat generated by the component. To help dissipate heat, a sheet of material selected for its heat transfer properties may be disposed over the EMI shield. A portion of the sheet may be folded over an edge of the EMI shield such that the sheet may cover a top surface of the sheet as well as tabs extending perpendicular to the top surface of the EMI shield. To facilitate the adhesion of the sheet to a smaller surface area of tabs, the sheet may include features forming a discontinuity in regions of the sheet aligned with the edge of the shield to facilitate folding the sheet. The discontinuity can include, for example, one or more holes or windows.

Claims:
What is claimed is: 
     
       1. A board assembly, comprising:
 a fence coupled to a circuit board, the fence forming a perimeter extending from the circuit board; 
 a lid comprising a planar surface and at least one tab extending from the planar surface at an edge, wherein the lid is placed over the fence such that the at least one tab engages the fence; and 
 a sheet of heat-transferring material disposed over the planar surface and the at least one tab, wherein the sheet has a plurality of holes extending through the sheet and aligned with the edge. 
 
     
     
       2. The board assembly of  claim 1 , wherein:
 the fence defines a closed loop. 
 
     
     
       3. The board assembly of  claim 2 , wherein:
 at least one component is coupled to the circuit board within the region enclosed by the fence. 
 
     
     
       4. The board assembly of  claim 1 , wherein the sheet further comprises:
 a graphite layer; and 
 an adhesive layer, wherein the adhesive layer is positioned between the graphite layer and the lid. 
 
     
     
       5. The board assembly of  claim 4 , wherein the sheet further comprises:
 a plastic layer; and 
 a second adhesive layer, wherein the second adhesive layer is positioned between the graphite layer and the plastic layer. 
 
     
     
       6. The board assembly of  claim 1 , wherein the plurality of holes further comprise:
 a sequence of holes evenly distributed along the edge. 
 
     
     
       7. The board assembly of  claim 1 , wherein the plurality of holes further comprise:
 a plurality of circular holes. 
 
     
     
       8. The board assembly of  claim 1 , wherein the plurality of holes further comprise:
 a plurality of slots. 
 
     
     
       9. Apparatus, comprising:
 a circuit board; 
 a component on the circuit board; 
 an electromagnetic interference shielding structure that covers the component; and 
 a heat-transferring sheet having at least one discontinuity that facilitates bending along the discontinuity to align with an edge of the electromagnetic interference shielding structure, wherein the heat-transferring sheet comprises:
 a first adhesive layer that is coupled to the electromagnetic interference shielding structure; 
 a layer of graphite on the first adhesive layer; 
 a second adhesive layer on the layer of graphite; and 
 an external layer over the second adhesive layer. 
 
 
     
     
       10. The apparatus defined in  claim 9  wherein the external layer comprises a plastic layer. 
     
     
       11. The apparatus defined in  claim 9  wherein the at least one discontinuity of the heat-transferring sheet is formed from a plurality of holes extending through each of the first adhesive layer, the graphite layer, the second adhesive layer, and the external layer. 
     
     
       12. The apparatus defined in  claim 9  wherein the at least one discontinuity of the heat-transferring sheet is formed from an opening in only the graphite layer. 
     
     
       13. The apparatus defined in  claim 9  wherein the electromagnetic interference shielding structure comprises:
 a fence; and 
 a lid having a planar surface that covers the fence, wherein the lid includes tab portions that extend perpendicularly from the planar surface and are secured to the fence. 
 
     
     
       14. The apparatus defined in  claim 9  wherein the second adhesive layer and the external layer cover the planar surface and the tab portions of the lid and wherein the first adhesive layer and the layer of graphite cover only the planar surface of the lid. 
     
     
       15. The apparatus defined in  claim 9  further comprising:
 an additional component that is adjacent to the component, wherein at least part of the heat-transferring sheet is interposed between the tab portions of the lid and the additional component and prevents the tabs portions from damaging the additional component. 
 
     
     
       16. The apparatus defined in  claim 9  wherein the circuit board has first and second opposing surfaces, wherein the component comprises a first component mounted on the first surface of the circuit board, the apparatus further comprising:
 a second component mounted on the second surface of the circuit board, wherein the heat-transferring sheet comprises a U-shaped sheet that covers the first component on the first surface of the circuit board and the second component on the second surface of the circuit board. 
 
     
     
       17. The apparatus defined in  claim 9  wherein the heat-transferring sheet encloses the component. 
     
     
       18. Apparatus, comprising:
 a circuit board; 
 a component on the circuit board; 
 a fence on the circuit board around the component; a lid having a planar portion and at least one tab portion that extends from the planar portion at an edge and is coupled to the fence; and 
 a graphite layer that covers the planar portion at the at least one tab portion of the lid, wherein openings in the graphite sheet facilitate bending at the edge between the planar portion and the tab portion of the lid. 
 
     
     
       19. The apparatus defined in  claim 18  wherein the graphite layer forms part of a heat-transferring sheet that comprises: a first adhesive layer that is coupled to the lid, wherein the graphite layer is on the first adhesive layer; a second adhesive layer on the graphite layer; and an external layer of the heat-transferring sheet that is on the second adhesive layer. 
     
     
       20. The apparatus defined in  claim 19  wherein the fence and the lid shield the component from electromagnetic interference.

Description:
BACKGROUND OF THE INVENTION 
     Electronic devices include several electronic components used to process and transmit electrical signals. During use, some components may generate electromagnetic waves that may interfere with the proper operation of other components. To prevent electromagnetic interference (EMI), the electronic device can include one or more EMI shields placed over the components. The shields can be constructed, for example, from stamped sheet metal forming a box that is clipped over the components. 
     During use, electronic device components may also generate heat that must be dissipated to ensure proper operation of the components. Placing an EMI shield over a component, however, may reduce the ability of the components to dissipate heat. To improve the heat dissipation of a shielded component, a sheet of heat conducting material can be placed on a top surface of the EMI shield. 
     SUMMARY OF THE INVENTION 
     This is directed to systems and methods for providing a graphite layer in an electronic device for enhancing heat transfer. 
     An electronic device component may be shielded from EMI using a shield placed over the component. The shield can be constructed, for example, from a piece of sheet metal having a planar or top surface from which side walls or tabs extend. Heat generated by the component may be in part trapped by the shield. To help dissipate the generated heat, a sheet of graphite material may be coupled to the shield. In some cases, the sheet can include several layers of different material that are coupled to each other. 
     The sheet may be disposed such that a portion of the sheet is coupled to the top surface and another portion of the sheet is coupled to the tabs. Because the sheet may include a fold over the edge of the shield, the sheet may include a discontinuity that facilitates the fold and enhances adhesion to the smaller surface area of the tabs. The discontinuity may include, for example, one or more holes, windows, openings, or entirely or partially empty or unfilled layer of material within the sheet. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The above and other objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
         FIG. 1  is a schematic view of an illustrative circuit board and component in accordance with some embodiments of the invention; 
         FIG. 2  is a schematic view of an illustrative circuit board and component over which a shield is placed in accordance with some embodiments of the invention; 
         FIG. 3  is a perspective view of an illustrative circuit board and component over which a shield is placed in accordance with some embodiments of the invention; 
         FIG. 4  is a top view of the illustrative circuit board and component over which a shield is placed of  FIG. 3  in accordance with some embodiments of the invention; 
         FIG. 5  is a sectional view of the component, shield, and material shown in  FIGS. 3 and 4  in accordance with some embodiments of the invention; 
         FIGS. 6A-6C  are sectional views of an illustrative electronic device each having a component and a shield over which material is provided in accordance with some embodiments of the invention; 
         FIGS. 7A-7F  are sectional views of illustrative sheets of material for use in accordance with some embodiments of the invention; 
         FIG. 8  is a perspective view of a sheet of material that may be adhered to a shield in accordance with some embodiments of the invention; 
         FIG. 9  is a top view of a three-dimensional disposition of the sheet of material of  FIG. 8  in accordance with some embodiments of the invention; 
         FIG. 10  is a flowchart of an illustrative process for constructing a sheet of material for transferring heat from a shield of a component in accordance with some embodiments of the invention; and 
         FIG. 11  is a flowchart of an illustrative process for adhering a sheet to a shield in accordance with some embodiments of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An electronic device can include a circuit board on which one or more electronic device components are placed.  FIG. 1  is a schematic view of an illustrative circuit board and component in accordance with some embodiments of the invention. As shown, component  104  is mounted to circuit board  102 . For example, component  104  can be mounted by soldering, surface mount technology (SMT), a conductive adhesive, or using any other suitable approach. Circuit board  102  can include any suitable type of board or circuit on which components can be mounted. For example, circuit board  102  can include a printed circuit board, flex circuit, or any other type of circuit. Component  104  can include any suitable type of electrical component such as, for example, a processor, controller, signal processor, communications module, or any other component coupled to a circuit board. 
     Some components may generate electromagnetic waves during use. These waves may propagate within the device and interfere with the proper functioning of other components. To prevent this, individual components can be shielded using an EMI shield. The EMI shield can be constructed from a conductive element such as a metal lid placed over the component. The lid can be secured within the electronic device using any suitable approach. In some cases, the lid can engage a fence that is secured to the circuit board around the component. Alternatively, the lid can be secured directly to the circuit board. 
       FIG. 2  is a schematic view of an illustrative circuit board and component over which a shield is placed in accordance with some embodiments of the invention. Circuit board  202  and component  204  can have some or all of the features of the circuit board  102  and component  104  ( FIG. 1 ), respectively. To shield component  204  from EMI, shield  210  can be placed over component  204 . Shield  210  can include a lid portion having a planar top surface that is placed adjacent to a surface of component  204  that is co-planar with a surface of circuit board  202 . To secure shield  210  over component  204 , shield  210  can include side walls (not shown) extending substantially perpendicular from the top surface. The side walls may engage a frame extending from circuit board  202 , for example using an interference fit, or via dimples or other features. 
     Different components can be provided near component  204  and shield  210 . For example, another circuit board and component(s) can be placed adjacent to circuit board  202 . As another example, a stand alone component such as a battery can be placed near component  204  and shield  210 . In the particular example of  FIG. 2 , battery  220  can be placed adjacent to circuit board  202  such that battery  220  is near shield  210 . 
     More detailed views of a board assembly having an EMI shield covered by a heat transfer material in accordance with embodiments of the invention are provided in  FIGS. 3 and 4 . In particular,  FIG. 3  is a perspective view of an illustrative board assembly and  FIG. 4  is a top view of the same board assembly. As shown, component  304  is mounted to circuit board  302 , and EMI shield  310  is mounted over component  304 . Also shown, is heat transfer material  320  disposed on EMI shield  310   
     EMI shield  310  can be constructed from one or more distinct elements. For example, EMI shield  310  can include fence  312  forming a wall extending perpendicular to a surface of circuit board  302 . Fence  312  can be secured to circuit board  302  using any suitable approach including, for example, using soldering. Fence  312  can include one or more segments disposed around the periphery of component  304 . The segments may be substantially continuous, and include a height that is similar to the height of component  304 . For example, fence  312  may have a height that is the same height as or marginally higher than the height of component  304 . In some cases, fence  312  may surround several components mounted to circuit board  302 . 
     To complete EMI shield  310 , lid  314  can be placed over fence  312  such that lid  314  engages fence  312 . Lid  314  can include planar surface  315  sized to correspond to the area enclosed by fence  312 . Lid  314  can also include tabs  316  extending substantially perpendicular from planar surface  315  such that tabs  316  may engage fence  312  to secure lid  314  to fence  312 . Lid  314  can include any suitable number of tabs extending from surface  315 . For example, lid  314  can include tabs placed apart by less than a maximum amount (e.g., no more than 3 mm separate tabs). In some cases, one or both of tabs  316  and fence  312  can include features for securing lid  314  to fence  312 . For example, each tab  316  can include a dimple that extends into a hole or opening of fence  312 . 
     Lid  314  can be constructed using any suitable approach. In some cases, lid  314  can be constructed from a piece of sheet metal that is stamped. As a result of the stamping process, tabs  316  can have sharp edges. When other components placed adjacent to lid  314  move or are jostled, for example, during a drop event, the other components may come into contact with tabs  316  and be damaged. If the other components include a battery module that has a relatively small outer shell (e.g., only a Mylar sheet) due to space constraints, the tabs may damage the battery should the battery come into contact with the tabs during a drop event. Accordingly, it may be desirable to provide an additional barrier along the edges of tabs  316 . 
     In addition, component  304  may generate heat during use. Because component  304  is enclosed by EMI shield  310 , and lid  314  is constructed from a metal, the heat generated by component  304  may be retained adjacent to component  304  and adversely affect the performance of component  304 . Different approaches can be used to enhance the heat transfer capabilities of the shield. In some cases, a layer of material selected for its heat transferring capabilities may be placed in contact with EMI shield  310  such that heat generated by component  304  may be transferred from EMI shield  310  and the layer of material away from component  304 . 
     Any suitable type of material may be used to transfer heat away from component  304 . For example, the material can include a carbon allotrope such as graphite, graphene, diamond, amorphous carbon, fullerenes, carbon nanotubes, carbon nanobuds, glassy carbon, carbon nanofoam, lonsdaleite, or other carbon allotrope. In some cases, other types of material can be used such as, for example, metals, composite materials, or other material that enables the transfer of heat. 
     Material may be disposed over any suitable portion of EMI shield  310  to form part of a board assembly. In some cases, some material may be provided on external portions of fence  312 . Such an approach, however, may not be preferable as external portions of fence  312  may be placed in contact with tabs  316 , which may adversely affect or even negate the heat transfer benefits of the material. 
     In some cases, the material may instead or in addition be provided on lid  314 . For example, a sheet of material may be placed on planar surface  315 . As another example, one or more sheets of material may be placed on tabs  316  disposed along each edge of planar surface  315 . Each sheet of material may be secured to a portion of lid  314  using any suitable approach including, for example, an adhesive. Because the surface area of tabs  316  may be relatively small (e.g., due to the small height of component  304 ), it may be difficult to adhere material to the tabs. In such cases, it may be simpler to provide material only on planar surface  315 . 
     In other cases, however, a same piece of material may be used to cover different regions of lid  314 . For example, as shown in  FIGS. 3 and 4 , material  320  may be disposed over lid  314  such that portion  322  of material  320  is disposed over planar surface  315  and portion  324  of material  320  is disposed over tabs  316 . The material may include a fold at an edge of planar surface  315  so that the same piece of material may extend over different planes of lid  314 . In particular, material  320  may include a 90 degree fold  326 . 
       FIG. 5  is an illustrative sectional view of the board assembly of  FIGS. 3 and 4  in accordance with some embodiments of the invention. To enhance thermal conduction and heat dissipation, material  320  may be disposed over shield  310 , such that portion  322  of the material is overlaid on a planar surface of shield  310  and portion  324  of the material is overlaid on a tab of shield  310 . Material  320  may include fold  326  corresponding to a boundary between portions  322  and  324  of the material, and that is aligned with an edge of shield  310 . 
     In addition, the disposition of material  320  may provide additional mechanical benefits within the assembly of electronic device  300 . As discussed above, shield  310  may include a lid having stamped tabs. Due to the stamping process, the tabs may have sharp edges that could cut other components that potentially come into contact with the tabs. Should the tabs of shield  310  come into contact with other components of electronic device such as, for example, battery  306 , an outer shell of battery  306  may be damaged, which may in turn could damage the internal components of battery  306 . By placing material  320  over the tabs of shield  310 , electronic device  300  may provide a barrier between shield  310  and other components of the device. 
     The material may be disposed over or around the shield using any suitable approach.  FIGS. 6A-6C  are sectional views of illustrative board assemblies each having a component and a shield over which material is provided in accordance with some embodiments of the invention. Board assembly  600 , shown in  FIG. 6A , can include component  604  mounted to circuit board  602 . Shield  610  may be placed over component  604  such that the component is enclosed within a volume defined by circuit board  602  and shield  610 . In some cases, circuit board  602  can include a second component  604 ′ coupled to a surface of circuit board  602  opposite the surface to which component  604  is coupled. Board assembly  600  can include a second shield  610 ′ coupled to circuit board  602  such that component  604 ′ is enclosed in a volume between circuit board  602  and shield  610 ′. Component  604 ′ and shield  610 ′ can be aligned in any suitable manner relative to component  604  and shield  610 . In some cases, shields  610  and  610 ′ can be aligned relative to one another to form a box-like shape. 
     Board assembly  600  can include sheet of material  620  disposed over at least one of shields  610  and  610 ′ to enhance heat dissipation. In one implementation, sheet  620  can be disposed in a U-shaped cross-section such that portion  622  of sheet  620  is disposed on a top surface of shield  610 , portion  622 ′ of sheet  620  is disposed on a top surface of shield  610 ′, and portion  624  of sheet  600  extends between portions  622  and  622 ′ along tabbed edges of the shields. In some cases, shields  610  and  610 ′ can be disposed such that the edges of each of shields  610  and  610 ′ form a substantially flat surface (e.g., a surface that extends in a single plane). 
     By providing a single piece of material extending between the top surfaces of shields  610  and  610 ′, the portions of material  620  adjacent to the tabs or edges of the shields may remain secured to the shields despite the discontinuous nature of the tabs, or despite the smaller surface area of the tabs. In addition, by enclosing one or both of components  604  and  604 ′ within a volume enclosed by material  620 , material  620  may provide a barrier to water or other foreign particles that could damage components  604  and  604 ′. 
     Board Assembly  630 , shown in  FIG. 6B , can include component  634  mounted to circuit board  632 . Shield  640  may be placed over component  634  such that the component is enclosed within a volume defined by circuit board  632  and shield  640 . In some cases, circuit board  632  can include a second component  634 ′ coupled to a surface of circuit board  632  opposite the surface to which component  634  is coupled, and can include a second shield  640 ′ coupled to circuit board  632  such that component  634 ′ is enclosed in a volume between circuit board  632  and shield  640 ′. Component  634 ′ and shield  640 ′ can be aligned in any suitable manner relative to component  634  and shield  640 . In some cases, shields  640  and  640 ′ can be aligned relative to one another to form a box-like shape. 
     Sheet of material  650  may be disposed in part over shield  640  (e.g., portion  652  of material  650 ) and over edge or tab portions of shield  640  and shield  640 ′ (e.g., portion  654  of material  650 ). In addition, sheet of material  650  may include portion  656  extending in a plane substantially co-planar with a top surface of shield  640  and adhered to another component  636  of electronic device  600  such that sheet of material  650  forms a step. In this implementation, material  650  may form a barrier to prevent water or other contaminants from reaching components  634  and  634 ′. 
     Board assembly  660 , shown in  FIG. 6C , can include component  664  mounted to circuit board  662 . Shield  670  may be placed over component  664  such that the component is enclosed within a volume defined by circuit board  662  and shield  670 . In some cases, circuit board  662  can include a second component  664 ′ coupled to a surface of circuit board  662  opposite the surface to which component  664  is coupled, and can include a second shield  670 ′ coupled to circuit board  662  such that component  664 ′ is enclosed in a volume between circuit board  662  and shield  670 ′. Component  664 ′ and shield  670 ′ can be aligned in any suitable manner relative to component  664  and shield  670 . In some cases, shields  670  and  670 ′ can be aligned relative to one another to form a box-like shape. 
     Sheet of material  680  may be disposed in a manner similar to that of material  620  shown in  FIG. 6A . In particular, material  680  may include portions  682  and  682 ′ disposed adjacent to top surfaces of shields  670  and  670 ′, respectively. Material  680  may also include portions  684  and  686  adjacent to edges of shields  670  and  670 ′ such that material  680  forms a closed loop around shields  670  and  670 ′, thus enclosing components  664  and  664 ′ in a closed volume. 
     Each of the sheets of material shown in  FIGS. 6A-6C  include at least one fold. Because of inherent stiffness, thickness, or other mechanical properties of the material, however, the sheet may resist bending and may peel up or adhere poorly on smaller surface areas (e.g., on tabs extending from a planar surface of a shield). Different approaches may therefore be used to provide a sheet of material to be placed on a surface of a shield in a device. In particular, different approaches may be used to create discontinuities in a sheet of material to facilitate bending.  FIGS. 7A-7F  are sectional views of illustrative sheets of material for use in accordance with some embodiments of the invention. 
     Each sheet can include several layers having different properties. In particular, each sheet can include a first adhesive layer  702  for adhering the sheet to a shield. Adhesive layer  702  can include, for example, an adhesive or glue, hook and fastener material, tape, or any other material used for adhering components together. Adhesive layer  702  can have any suitable thickness. In some cases, the thickness of layer  702  can be the smallest thickness required to ensure that the sheet will adhere to an EMI shield. 
     After first adhesive layer  702 , each sheet can include heat-transferring layer  704 . For example, each sheet can include a layer having a thickness selected to provide a particular amount of heat transfer. In some cases, the thickness of layer  704  may be selected based on mechanical properties of the material. Layer  704  can be constructed from any material suitable for transferring heat away from a component. For example, layer  704  can be constructed from graphite, a metal, a composite material, or any other material operative to enable or enhance heat transfer. 
     Second adhesive layer  706  can be provided on a surface of layer  704  opposite the surface to which first adhesive layer  702  is provided. Second adhesive layer  706  may be constructed from the same material as layer  702 . Second adhesive layer  706  may have the same or different mechanical and structural attributes as first adhesive layer  702 . For example, second adhesive layer  706  may have a same thickness as first adhesive layer  702 . 
     An external layer  708  can be coupled to second adhesive layer  706  to provide an external surface or shell for each sheet. External layer  708  may be selected from a material having any desired mechanical attributes (e.g., resistance to abrasion, puncture, or impacts). External layer  708  can be constructed from any suitable material including, for example, Mylar®, PET, or any other plastic or composite material. 
     Different approaches can be used to ensure that the sheet of material will fold at an appropriate location. In some cases, the sheet of material can simply be folded without any modifications. Sheet  710 , shown in  FIG. 7A , may include no particular features for enabling a fold along line  712 . During assembly, sheet  710  may simply be forced to fold along line  712 , which may correspond to an edge in a shield over which sheet  710  is disposed. 
     Sheet  720 , shown in  FIG. 7B , may include several holes  724  provided through sheet  720  along line  722  to facilitate folding. Holes  724  may have any suitable shape or size. For example, holes  724  may include a regular or irregular pattern or distribution of holes along a line or shape corresponding to a fold region of sheet  720 . Each of holes  724  can include one or more of circular or elliptical holes, polygonal holes, slots, or any other type of opening extending through sheet  720 . Holes  724  may be constructed using any suitable approach including, for example, by punching or stamping holes in sheet  720  (e.g., when sheet  720  is cut). 
     Sheet  730 , shown in  FIG. 7C , may include region  736  corresponding to line  732  in which a portion of heat-transferring layer  704  is removed (e.g., an opening or a window in sheet  730 ) to facilitate folding. Any suitable amount of layer  704  may be removed along line  732 . For example, the entirety of layer  704  may be removed along line  732 . Alternatively, region  736  may include several distinct windows or openings having the same or different sizes distributed along line  732 . The windows may extend through any suitable amount of line  732  including, for example, any amount in the range of 25% to 75%, or more than 75%. The windows of region  736  can be constructed using any suitable approach including, for example, laying layer  704  in manner that has windows, or removing portions of layer  704  to form region  736 . 
     Sheet  740 , shown in  FIG. 7D , may include holes  744  extending through sheet  740  along line  742 , combined with region  746  in which a portion of heat-transferring layer  704  is removed along line  742 . Holes  744  may include some or all of the features of holes  724  described above, and region  746  may include some or all of the features of region  736  described above. In particular, holes  744  may extend through sheet  740  in both regions where layer  704  is present and through regions where layer  704  is absent (e.g., region  746 ). 
     Sheet  750 , shown in  FIG. 7E , may include region  754  associated with layer  704  and region  756  associated with layer  702 . In each of regions  754  and  756 , the associated layers may be removed starting at line  752  and extending towards portions of sheet  750  that are not placed adjacent to a top surface of a shield. For example, layers  702  and  704  may be removed in regions of sheet  750  that are placed adjacent to a tab extending from a shield lid. The thinner portions of sheet  750  (e.g., portions having only layers  706  and  708 ) may then easily fold at line  752 . 
     Sheet  760 , shown in  FIG. 7F , may include region  764  associated with layer  704 . In region  764 , the associated layer may be removed starting at line  762  and extending towards portions of sheet  760  that are not placed adjacent to a top surface of a shield. For example, layer  704  may be removed in regions of sheet  750  that are placed adjacent to a tab extending from a shield lid. The thinner portions of sheet  750  (e.g., portions having only layers  702 ,  706 , and  708 ) may then easily fold at line  752 . 
       FIG. 8  is a top view of a sheet of material that may be adhered to a shield in accordance with some embodiments of the invention.  FIG. 9  is a perspective view of a three-dimensional disposition of the sheet of material of  FIG. 8  in accordance with some embodiments of the invention. Sheet  800  can include a discontinuous or castellated border that corresponds to different features of the shield. For example, sheet  800  can include a border that matches the shape and dimensions of the shield. In addition, sheet  800  can include one or more tabs  810  that may fold out of primary surface  805  of sheet  800 . For example, tab  810  may be in a plane perpendicular to a plane of primary surface  805  such that primary surface  805  may adhere to a top surface of a shield lid, and tab  810  may adhere to a tab or edge extending from the top surface of the shield lid. In some cases, sheet  800  can be shaped to correspond to discontinuities or variations in shape of the shield (e.g., step  814 ). To allow tab  810  to bend relative to primary surface  805 , sheet  800  can include a sequence of perforations or other feature along edge  812  that facilitates bending. 
     The following flowcharts describe illustrative processes that relate to the construction and use of heat-transferring sheet on a shield.  FIG. 10  is a flowchart of an illustrative process for constructing a sheet of material for transferring heat from a shield of a component in accordance with some embodiments of the invention. Process  1000  can begin at step  1002 . At step  1004 , several layers of material can be combined to form a sheet. For example, layers of adhesive, graphite, and an external material can be combined to form a sheet. At step  1006 , a shape can be stamped into the sheet. For example, a stamp corresponding to a shape of a shield or of a shield lid can be used to cut away a portion of the sheet. In some cases, a stamp having several shapes can be used to cut away several shapes from a single sheet. At step  1008 , holes or other discontinuities can be provided in the sheet along at least one edge at which the sheet is folded. For example, a sequence of holes can be provided along a line in the sheet around which the sheet will be folded (e.g., where the sheet will fold to adhere to a top surface and to a tab of a shield lid). The holes can be provided using any suitable approach including, for example, stamping, drilling, laser cutting or any other such approach. Process  1000  can then end at step  1010 . 
       FIG. 11  is a flowchart of an illustrative process for adhering a sheet to a shield in accordance with some embodiments of the invention. Process  1100  can begin at step  1102 . At step  1104 , a sheet of material having a sequence of holes can be provided. For example, a sheet constructed using process  1000  ( FIG. 10 ) can be provided. At step  1106 , the sheet may be positioned over a shield such that the holes in the sheet are aligned with an edge of a shield. For example, the sheet may be positioned such that holes that facilitate the bending of the sheet are aligned with an edge of a shield lid from which tabs extend. At step  1108 , the sheet may be adhered to the shield. For example, an adhesive layer of the sheet may be secured to the shield lid. Process  1100  can then end at step  1110 . 
     The above described embodiments of the present invention are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow.

Metadata:
Filing Date: 20110831
Publication Date: 20141104
Grant Date: 20141104
Priority Date: 20110831
Inventors: HILL MATTHEW
DINH RICHARD HUNG MINH
TAN TANG
Assignee: APPLE INC
CPC Classifications: [{"code": "Y10T29/49826", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K7/20481", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0032", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K7/20481", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0032", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 47743457