PATENT DOCUMENT

Publication Number: US-8766124-B2
Application Number: US-89511310-A
Country: US
Kind Code: B2

Title: Contaminent resistant membrane in a dome switch and methods for making the same

Abstract:
A dome switch can include a dome mounted to a circuit board and secured by a sheet constructed from a material that is impermeable to air. To allow air enclosed by a volume between the dome and the circuit board to be expelled when the dome is depressed, the sheet can include at least one venting hole through which air can flow to the environment of the switch. To prevent contaminants from accessing the volume between the dome and the circuit board through the at least one venting hole, the dome switch can include a membrane positioned over the venting hole. The membrane can be constructed from a material that is permeable to air, but impermeable to contaminants. In some cases, the membrane can be constructed from a mesh material.

Claims:
What is claimed is: 
     
       1. A dome switch, comprising:
 a circuit board comprising at least two contact pads; 
 a dome mounted on the circuit board, and a periphery of the dome being in electrical contact with one of the at least two contact pads; 
 a sheet attached to the dome and to the circuit board, a portion of the sheet covering the dome, 
 wherein the portion of the sheet covering the dome includes a plurality of vents to vent air enclosed under the dome; and 
 a membrane coupled to the sheet and positioned above the dome, 
 wherein the membrane is substantially permeable to air and substantially impermeable to contaminants to at least one of inhibit or prevent contaminants from passing through the plurality of vents. 
 
     
     
       2. The dome switch of  claim 1 , wherein:
 the plurality of vents of the sheet is positioned adjacent to the periphery of the dome. 
 
     
     
       3. The dome switch of  claim 1 , wherein:
 the membrane is positioned between the sheet and the dome. 
 
     
     
       4. The dome switch of  claim 3 , wherein the membrane further comprises:
 a central region covering the plurality of vents, wherein the central region has a first thickness; and 
 an edge region adjacent to the central region, wherein the edge region has a second thickness. 
 
     
     
       5. The dome switch of  claim 4 , wherein:
 the second thickness is variable. 
 
     
     
       6. The dome switch of  claim 5 , wherein:
 the second thickness ranges between an amount equal to the first thickness and a smaller amount. 
 
     
     
       7. The dome switch of  claim 1 , wherein:
 at least a portion of the sheet is positioned between the membrane and the dome. 
 
     
     
       8. The dome switch of  claim 1 , wherein:
 the dome switch comprises at least two membranes; and 
 one of the at least two membranes does not cover all of the plurality of vents. 
 
     
     
       9. The dome switch of  claim 8 , wherein:
 the at least two membranes overlap over one of the plurality of vents. 
 
     
     
       10. A method for constructing a dome switch, comprising:
 aligning a dome with a contact pad of a circuit board; 
 applying a sheet to the dome and circuit board, a portion of the sheet covering the dome, 
 wherein the portion of the sheet covering the dome includes a plurality of vents, and 
 wherein the sheet is formed from a material that is substantially impermeable to air; 
 applying a membrane to the sheet, 
 wherein the membrane is formed from a material that is substantially permeable to air and substantially impermeable to contaminants, and 
 wherein the membrane is positioned above the dome and over the plurality of vents formed in the sheet; and 
 attaching the sheet and membrane to the circuit board over the dome to secure the dome to the circuit board such that a portion of the sheet comprising the plurality of vents is overlaid on the dome, wherein air within the dome vents through the membrane. 
 
     
     
       11. The method of  claim 10 , further comprising:
 applying an adhesive to a surface of the sheet, wherein the adhesive is operative to couple at least one of the membrane, the dome and the circuit board with the surface of the sheet. 
 
     
     
       12. The method of  claim 10 , wherein:
 the membrane is constructed from a mesh material, wherein openings in the mesh are smaller than the size of liquid vapor. 
 
     
     
       13. The method of  claim 10 , wherein the membrane is constructed from at least one of:
 polytetrafluoroethylene; 
 Teflon; 
 nylon; 
 polyester; and 
 polyurethane. 
 
     
     
       14. The method of  claim 10 , wherein:
 a first surface of the membrane is coupled to a portion of the first surface of the sheet; and 
 the circuit board is coupled to another portion of the first surface of the sheet. 
 
     
     
       15. The method of  claim 14 , further comprising:
 applying an adhesive to a second surface of the membrane, wherein the second surface of the membrane is opposite the first surface of the membrane; and 
 coupling at least a portion of the second surface of the membrane to an exterior surface of the dome. 
 
     
     
       16. The method of  claim 10 , wherein:
 the membrane is coupled to a first surface of the sheet; and 
 the circuit board is coupled to a second surface of the sheet, wherein the second surface of the sheet is opposite the first surface of the sheet. 
 
     
     
       17. The method of  claim 10 , wherein the sheet comprises two vents, and at least a portion of the membrane is positioned over the two vents. 
     
     
       18. A dome switch, comprising:
 a dome placed on a contact pad, wherein the dome is operative to close an electrical circuit when the dome is at least partially inverted; 
 a sheet constructed from a material substantially impermeable to air, the sheet being secured to the dome to form an air tight seal around the dome, 
 wherein a portion of the sheet overlaying the dome includes a plurality of vents providing a passage for air through the sheet; and 
 a membrane coupled to the sheet and positioned between the sheet and the dome, 
 wherein the membrane covers the entirety of the plurality of vents formed in the sheet, and 
 wherein the membrane is substantially impermeable to contaminants. 
 
     
     
       19. The dome switch of  claim 18 , further comprising:
 a circuit board comprising the contact pad, wherein the sheet is coupled to the circuit board. 
 
     
     
       20. The dome switch of  claim 18 , further comprising:
 at least two membranes, wherein the at least two membranes overlap over at least one of the plurality of vents of the sheet.

Description:
BACKGROUND OF THE INVENTION 
     Users can provide inputs to electronic devices using many different approaches. In some cases, an electronic device can include a dome switch, which can be actuated to provide a detectable input. The dome switch can be constructed by placing a conductive dome over a contact pad of a circuit board. When the dome is pressed, the dome can invert such that an inner surface of the dome contacts the contact pad. A volume of air enclosed between the dome and the circuit board may be expelled from the dome when the dome is depressed, for example through vents of the dome switch. The vents however, may also allow foreign contaminants or particles to enter the volume enclosed between the inner surface of the dome and the circuit board. The foreign contaminants or particles can adversely affect the operation of the dome switch by causing rust, oxidation, dendrite growth, or deposits of foreign substances. 
     SUMMARY OF THE INVENTION 
     A dome switch having a membrane that is impermeable to contaminants but permeable to air, and methods for constructing the same, are provided. 
     A dome switch can include a circuit board having a contact pad, and a dome mounted on the circuit board over the contact pad. An internal surface of the dome can be offset from the contact pad such that an electrical path exists between the dome and the contact pad when the dome is depressed and comes into contact with the contact pad. To secure the dome to the circuit board, an adhesive sheet can be disposed over the dome and the circuit board. The adhesive sheet can include at least one vent through which air enclosed in a volume between the dome and the circuit board can be expelled when the dome is depressed. To prevent contaminants from entering the volume between the dome and the circuit board through the vent, the dome switch can include a membrane covering the vent. The membrane can be constructed from a material that is permeable to air to allow the dome to vent, but impermeable to contaminants to prevent damage to the dome. 
     The membrane can be disposed in any one of a number of different configurations to prevent ingress of undesired material into the dome. In one approach, the membrane can be disposed between the sheet and the dome or circuit board. In another approach, the membrane can be disposed over the sheet, such that the sheet is between the membrane and the dome or circuit board. The dome switch can include any suitable number of membranes including, for example, a single membrane covering one or more vents. As another example, the dome switch can include several membranes each covering different vents, or combining to cover a single vent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present invention, its nature and various advantages will be more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings in which: 
         FIG. 1A  is a cross-sectional view of an illustrative dome switch; 
         FIG. 1B  is a cross-section view of the illustrative dome switch of  FIG. 1A  when the dome is depressed; 
         FIGS. 2A-2C  are top views of illustrative dome switches having vents in accordance with some embodiments of the invention; 
         FIG. 3  is a cross-sectional view of a dome switch having a protective membrane in accordance with one embodiment of the invention; 
         FIG. 4  is a cross-sectional view of another dome switch having a protective membrane in accordance with one embodiment of the invention; 
         FIGS. 5A and 5B  are cross-sectional views of an illustrative dome switches having several membranes in accordance with some embodiments of the invention; 
         FIG. 6  is a cross-sectional view of an illustrative sheet and membrane for use with a dome switch in accordance with some embodiments of the invention; and 
         FIG. 7  is a flowchart of an illustrative process for assembling a dome switch in accordance with one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A dome switch used in an electronic device can include a dome mounted on a circuit board and defining a volume between the dome and the circuit board. To expel air from the volume when the dome is depressed, the dome can include venting holes that provide a path for air between an environment and the volume. In some cases, the venting holes can be provided in a sheet placed over the dome and circuit board and used to secure the dome to the circuit board. A membrane can be placed over the venting holes of the sheet to prevent contaminants from entering the volume while allowing air to be expelled from the volume. 
     A dome switch can be constructed such that a dome is depressed to provide a detected signal to an electronic device.  FIG. 1A  is a cross-sectional view of an illustrative dome switch.  FIG. 1B  is a cross-sectional view of the illustrative dome switch of  FIG. 1A  when the dome is depressed. Dome switch  100  can include dome  110  mounted on circuit board  102 . Circuit board  102  can include any suitable electrical component or circuit providing electrically conductive paths used for transferring signals. For example, circuit board  102  can include a printed circuit board or a flex circuit. Circuit board  102  can include outer contact pad  104  and inner contact pad  106  deposited on a surface of circuit board  102 . Outer contact pad  104  and inner contact pad  106  can be electrically isolated so as to form a switch in an electrical circuit. 
     Dome  110  can be disposed on circuit board  102  to interface with outer contact pad  104  and inner contact pad  106 . In some cases, dome  110  can be disposed such that a periphery of dome  110  is placed in electrical contact with outer contact pad  104 . Dome  110  can include a conductive inner surface  112  such that when dome  110  is depressed, as shown in  FIG. 1B , inner surface  112  provides a conductive path between outer contact pad  104  and inner contact pad  106 , thus closing the switch formed by the contact pads. 
     Dome  110  can be constructed from any suitable material. For example, dome  110  can be constructed from a conductive material (e.g., sheet metal). As another example, dome  110  can be constructed from a non-conductive material, but can include a conductive coating applied to internal surface  112  (e.g., the surface of dome  110  that comes into contact with inner contact pad  106 ). Dome  110  can be constructed using any suitable approach including, for example, by stamping, machining, molding, or combinations of these. 
     Dome  110  can be secured to circuit board  102  using any suitable approach. In some cases, dome  110  can be coupled to circuit board  102  using a soldering or surface mount technology (SMT) process. Alternatively, a film or sheet  120  can be placed over dome  110  and adhered to circuit board  102  such that dome  110  is trapped between sheet  120  and circuit board  102 . For example, sheet  120  can include a thin film of material on which an adhesive is placed. To properly secure dome  110  to circuit board  102 , sheet  120  can extend beyond a periphery of dome  110 , for example by at least an amount required to provide a hermetic seal between dome  110  and circuit board  102 . This seal may be important, for example, to prevent debris or liquids from entering a volume  130  between circuit board  102  and dome  110 . 
     Sheet  120  can be constructed from any suitable material. In some embodiments, sheet  120  can be constructed from a material that is impermeable to air such as, for example, a plastic (e.g., polypropylene, polystyrene, polyethylene, polyester, polyamides, polyurethane, polycarbonate, or polyethylene). By using a material that is impermeable to air, contaminants or other particles may not pass through sheet  120  to access volume  130  and damage dome switch  100 . 
     When dome  110  is pressed and at least partially inverted, air enclosed in volume  130  between circuit board  102  and dome  110  may need to be expelled. If the air cannot be expelled when dome  110  is depressed, the size of volume  130  may diminish but the amount of air in volume  130  may remain the same. This may cause the air pressure within volume  130  to increase and resist the deformation of dome  110 . Furthermore, if the air pressure increases in dome  130 , dome switch  100  may not provide a desired tactile feedback (e.g., a tactile “click”) to a user. Therefore, to allow air to escape from volume  130 , sheet  120  can include vents  122  in the regions of the sheet that are adjacent to the dome. For example, vents  122  can be positioned entirely over the dome. As another example, vents  122  can be positioned around the interface between dome  110  and outer contact pad  104  (e.g., around the periphery of the dome). 
     Air initially enclosed within volume  130  can follow any suitable path to reach environment  140  outside of dome switch  100 . In some cases, when dome  110  is depressed, the increased air pressure in volume  130  can cause dome  110  to be slightly raised from the surface of circuit board  102 . When dome  110  rises, air can flow between dome  110  and circuit board  102  towards vents  122 . In some cases, air may flow between outer surface  114  of dome  110  and sheet  120  to reach vents  122 . 
     Alternatively, dome  110  or circuit board  102  can include openings, grooves, channels, or other paths for directing air from volume  130  towards vents  122 . 
     Vents  122  of dome switch  100  can include any suitable property for ensuring a proper venting of volume  130 .  FIGS. 2A-2C  are top views of illustrative dome switches having vents in accordance with some embodiments of the invention. Dome switches  200 A shown in  FIG. 2A ,  200 B shown in  FIG. 2B , and  200 C shown in  FIG. 2C , can include circuit board  202 , dome  210  and sheet  220  having some or all of the features of the corresponding elements of dome switch  100  ( FIGS. 1A and 1B ). Dome switch  200 A can include several vents  222  disposed in a portion of sheet  220  overlaid on dome  210 . For example, dome switch  200 A can include three distinct vents  222 . The vents can cover any suitable area of dome  210  including, for example, an amount in the range of 15% to 50%, 20% to 40%, or 25% to 30%. Vents  222  can have any suitable shape including, for example, polygonal shape, circular or curved shape, or an arbitrary shape. The particular number, size and shape of the vents can be selected from an amount of air to expel from a volume underneath dome  210 . 
     In some cases, one or more vents can be disposed adjacent to an interface between dome  210  and circuit board  202  (e.g., around periphery  212  of dome  210 ). Dome switch  200 B, shown in  FIG. 2B , can include vents  232  disposed at least partially over periphery  212 . As discussed above in connection with dome switch  200 A, dome switch  200 B can include any suitable number of vents  232 , and vents  232  can include any suitable size or shape, and can cover any suitable area of dome  210 , sheet  220 , or periphery  212 . 
     In some cases, one or more vents can be disposed in a region of sheet  220  that does not overlap with dome  210 . Dome switch  200 C, shown in  FIG. 2C , can include vents  242  disposed so as not to overlap with dome  210 . As discussed above in connection with dome switch  200 A, dome switch  200 C can include any suitable number of vents  242 , and vents  242  can include any suitable size or shape, and can cover any suitable area of sheet  220 . Although  FIGS. 2A-2C  show vents disposed in different types of areas of sheet  220 , it will be understood that a dome switch can include one or more vents disposed in any position on sheet  220 . 
     In some cases, the size, shape, and/or number of vents used in a dome switch can be selected based on the position of a vent relative to the dome. For example, vents disposed closer to periphery  212  can be smaller than vents disposed away from periphery  212 . As another example, a dome switch can include fewer vents disposed adjacent to periphery  212  than vents disposed away from periphery  212 . This may be because air expelled from a volume underneath dome  210  can more rapidly reach a vent disposed adjacent to periphery  212 , and may therefore be more quickly expelled from the volume than through a vent disposed farther away from the volume. 
     Because vents of a dome switch provide a path for expelling air from a volume underneath a dome, the vents can also provide a path for contaminants or other debris from an environment to reach the volume underneath the dome. Contaminants such as, for example, foreign particles, debris, liquid (e.g., sweat, water, juices, coffee, and soda), or other substances can cause mechanical and/or electrical disruptions or failure of the dome switch should they reach the inner contact pad or outer contact pad of the dome switch. For example, debris or liquid may cause dome switch  200  to short. As another example, contaminants can cause rust, oxidation, corrosion, dendrite growth, or salt, sugar or chemical deposits. To prevent the contaminants from reaching the volume underneath the dome, the vents may be obstructed. 
     A dome switch can include a membrane for preventing contaminants from reaching a volume underneath a dome.  FIG. 3  is a sectional view of a dome switch having a protective membrane in accordance with one embodiment of the invention. Dome switch  300  can include circuit board  302  having outer contact pad  304  and inner contact pad  306 , dome  310 , and sheet  320  including vents  322 . The various components of dome switch  300  can include some or all of the features of corresponding elements of dome switch  100  ( FIGS. 1A-1B ) or dome switches  200 A,  200 B and  200 C ( FIGS. 2A-2C ). To prevent contaminants from passing through vents  322 , dome switch  300  can include membrane  330  covering at least vents  322  of sheet  320 . 
     Membrane  330  can be constructed from any suitable material. In particular, membrane  330  can be constructed from any material that allows air to pass through, but prevents contaminants from passing through. In some embodiments, membrane  330  can be constructed from a single layer or multi-layer mesh material. The vents in the mesh can be selected such that air can pass through the mesh, but such that contaminants of a particular size cannot. The minimum mesh size can be selected based on any suitable criteria including, for example, the size of known contaminants, contaminants of a particular environment corresponding to where the dome switch will be used, contaminants from susceptible to damage the dome switch, or the size of any other contaminant. The particular material used for the membrane can include, for example, porous plastic (e.g., a porous polytetrafluoroethylene), Teflon, nylon, polyester, polyurethane, a composite material, organic material, synthetic material, or combinations of these. 
     In some cases, membrane  330  can include a treatment for improving the impermeability of the membrane to contaminants. For example, a hydrophobic or oleophobic treatment can be applied to the membrane. As another example, a surface treatment increasing the resistance of the membrane to abrasion or other forms of damage. The treatments can include, for example, the application of materials or substances to a surface of the membrane (e.g., surface treatments), or incorporating materials or substances within membrane  330  (e.g., between several layers or as part of a layer of membrane  330 ). 
     Membrane  330  can be secured to dome switch  300  using any suitable approach. In one implementation, membrane  330  can be coupled to one or both of sheet  320  and dome  310 . For example, an adhesive layer can be placed between first surface  332  (e.g., an upper surface) of membrane  330  and second surface  324  (e.g., a bottom surface) of sheet  320  to secure the membrane to the sheet. When sheet  320  is placed over dome  310  and circuit board  302  to secure dome  310  to circuit board  302 , membrane  330  can be retained between dome  310  and sheet  320 . In some cases, additional adhesive can be placed between second surface  334  (e.g., a lower surface) of membrane  330  and first surface  312  (e.g., an upper or outer surface) of dome  312 . This may prevent membrane  330  from moving relative to dome  310 . 
     Membrane  330  can have any suitable position relative to sheet  320 . In the example of dome switch  300 , membrane  330  is positioned between sheet  320  and dome  310 . Because membrane  330  may typically be smaller than sheet  320 , this approach can ensure that a bond between membrane  330  and sheet  320  is protected from environment  340  by at least the thickness of sheet  320 . In particular, this approach may reduce peeling of membrane  330  from sheet  320 . 
       FIG. 4  is a sectional view of another dome switch having a protective membrane in accordance with one embodiment of the invention. Dome switch  400  can include circuit board  402  having outer contact pad  404  and inner contact pad  406 , dome  410 , sheet  420  including vents  422 , and membrane  430 . The various components of dome switch  400  can include some or all of the features of corresponding elements of dome switch  300  ( FIG. 3 ). Unlike dome switch  300 , membrane  430  can be positioned such that sheet  420  is between dome  410  and membrane  430 . In particular, first surface  432  (e.g., a lower or inner surface) of membrane  430  can be coupled to first surface  412  (e.g., an upper or outer surface) of sheet  420 . This approach can ensure that sheet  420  can be coupled directly to the entire outer surface of dome  410 , and can therefore enhance the bond between dome  410  and circuit board  402 . 
     A dome switch can include any suitable number of membranes covering vents within a sheet. In some cases, a dome switch can include several distinct membranes.  FIGS. 5A and 5B  are cross-sectional views of illustrative dome switches having several membranes in accordance with some embodiments of the invention. Dome switches  500 A and  500 B can include circuit board  502 , dome  510 , sheet  520 , and vents  522 A,  522 B and  522 C in sheet  520  having some or all of the features of corresponding elements of the other dome switches described herein. In contrast with the dome switches described above, sheet  520  can include membranes  530  and  532  positioned at least partially over vents  522 A,  522 B and  522 C in a manner that prevents the ingress of contaminants. 
     The several membranes of dome switch  500 A can be disposed using any suitable approach. In one implementation, each membrane can be positioned over one or more distinct vents  522 A,  522 B and  522 C. In the example shown in  FIG. 5A , membrane  530  can be disposed over a single vent  522 A, and membrane  532  can be disposed over vents  522 B and  522 C. Each of membranes  530  and  532  can be disposed over any suitable number of vents of sheet  520 . For example, including, for example, a membrane such as membrane  532  can be disposed to overlap with a number of vents that ranges from one to the total number of vents in sheet  520 . 
     In some cases, two or more membranes of a dome switch can be disposed so that they at least partially overlap. Dome switch  500 B, shown in  FIG. 5B , can include membranes  540  and  542  disposed such that membranes  540  and  542  overlap. In some cases, the overlapping portions of membranes  540  and  542  can cover a vent (e.g., vent  522 B). 
     Membranes  540  and  542  can have any suitable thickness. In some cases, the overlapping portions of membranes  540  and  542  can have a reduced thickness selected such that the thickness of the overlapping portions of membranes  540  and  542  substantially match the thickness of one or both of the non-overlapping portions of membrane  540  and membrane  542 . This approach may ensure that sheet  520  is coupled to a smooth surface that does not have height variations. In some cases, the thickness of a membrane can vary, for example with a tapered edge away from a vent and a thicker region over the vent to provide more substantial protection in regions through which contaminants attempt to pass. The membrane can have any suitable thickness including, for example, a thickness in the range of 1.0 mm to 0.05 mm (e.g., 0.5 mm). 
     In some cases, a membrane can be coupled to a sheet before the sheet and membrane are coupled to a circuit board and dome.  FIG. 6  is a sectional view of an illustrative sub-assembly  600  including sheet  620  and membrane  630  for use with a dome switch in accordance with some embodiments of the invention. Sheet  620  can include vent  622  through which air can flow. To prevent contaminants from passing through vent  622 , membrane  630  can be coupled to sheet  620  opposite the vent. In particular, membrane  630  can include central region  632  positioned opposite vent  622  and edge regions  634  and  635  extending around the periphery of vent  622 . Edge regions  634  and  635  can have any suitable thickness including, for example, a variable and decreasing thickness (e.g., the thickness can vary between a zero or minimum value to a maximum value corresponding to region  632 ). In some embodiments, central region  632  can have a thickness at least equal to the largest thickness of one or both of edge regions  634  and  635 . 
     An adhesive can be applied to a surface of one or both of sheet  620  and membrane  630  such that membrane  630  can be securely coupled to sheet  620 . In some embodiments, one or both of the membrane and sheet can be constructed with an embedded adhesive layer (e.g., forming a tape) such that the membrane and sheet can be put in contact with one another to securely couple the components together. Assembled sheet and membrane component  600  can be placed over a dome in any suitable orientation. For example, component  600  can be disposed such that membrane  630  is placed in contact with a dome, and sheet  620  forms an outer surface of the dome switch. As another example, component  600  can be disposed such that sheet  620  is placed in contact with a dome, and membrane  630  forms an exposed outer surface of the dome switch. 
       FIG. 7  is a flowchart of an illustrative process for assembling a dome switch in accordance with one embodiment of the invention. Process  700  can begin at step  702 . At step  704 , a sheet can be defined, where the sheet can include at least one vent. For example, a sheet can be defined from a material that is impermeable to air, and in which at least one vent can be created (e.g., cut out). In some embodiments, the vent can be positioned on the sheet relative to an expected position of a dome. At step  706 , a membrane can be coupled to the sheet. For example, a membrane can be placed over the sheet such that the membrane covers the vent of the sheet. In some embodiments, portions of the membrane can extend beyond a periphery of the vent to ensure that air can pass through the sheet only by passing through the membrane. The membrane can be selected from a material that is permeable to air but impermeable to contaminants. At step  708 , a dome can be aligned with contact pads of a circuit board. For example, a periphery of a dome can be disposed over an outer contact pad such that an interior surface of the dome can come into contact with an inner contact pad when the dome is depressed. At step  710 , the sheet and membrane can be coupled to the circuit board over the dome. For example, the sheet and membrane can be aligned with the circuit board and dome such that the vent is disposed at a desired position relative to the dome. In particular, the sheet and membrane can be positioned in the vicinity of the dome (e.g., in the vicinity of the periphery of dome) to ensure that air flowing a volume enclosed by the dome and a dome switch environment passes through the vent and the membrane. By coupling the sheet and the membrane to the circuit board over the dome, the dome can be securely retained in contact with the circuit board. Process  700  can then end at step  712 . 
     It will be understood that the foregoing is only illustrative, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of embodiments of the invention. For example, the shapes of various components shown in the drawings are only illustrative, and many of these components can have different shapes if desired. This is not limited to dome switches, but rather can apply to any of several types of switches.

Metadata:
Filing Date: 20100930
Publication Date: 20140701
Grant Date: 20140701
Priority Date: 20100930
Inventors: ALVAREZ FELIX
DABOV TEODOR
SANFORD EMERY
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H2213/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/82", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49105", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/82", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2215/048", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 45888857