PATENT DOCUMENT

Publication Number: US-8878060-B2
Application Number: US-201113286006-A
Country: US
Kind Code: B2

Title: Zero force conductive membrane

Abstract:
An electronic device may include housing structures, electronic components, and other structures. A gap may be formed between the structures. A membrane structure may be used to bridge the gap to form and environmental seal and electrical pathway between the structures. The membrane structure may be deployed using a temporary biasing member or may be installed by forming an inflatable structure. The inflatable structure may include an elastomeric balloon that may be pressurized. Adhesive such as conductive adhesive may be used in attaching the membrane structure to the structures in the electronic device. An inflatable structure may be depressurized following installation in an electronic device to minimize residual forces.

Claims:
What is claimed is: 
     
       1. An electronic device comprising: structures that are separated by a gap; and an inflatable structure that bridges the gap and that is attached to the structures with adhesive, wherein the adhesive comprises conductive adhesive. 
     
     
       2. The electronic device defined in  claim 1  wherein the inflatable structure comprises an elastomeric balloon. 
     
     
       3. The electronic device defined in  claim 2  wherein the inflatable structure comprises a sheet of material that is wrapped at least partly around the elastomeric balloon. 
     
     
       4. The electronic device defined in  claim 3  wherein the sheet of material includes a layer of material that is at least partly coated with the conductive adhesive. 
     
     
       5. The electronic device defined in  claim 4  wherein the layer of material comprises a sheet of metal. 
     
     
       6. The electronic device defined in  claim 4  wherein the layer of material comprises a metallized polymer sheet. 
     
     
       7. The electronic device defined in  claim 4  wherein the layer of material comprises a metal mesh. 
     
     
       8. The electronic device defined in  claim 2  wherein the conductive adhesive at least partly coats the elastomeric balloon. 
     
     
       9. The electronic device defined in  claim 2  wherein the elastomeric balloon comprises a depressurization feature. 
     
     
       10. The electronic device defined in  claim 9  wherein the depressurization feature comprises a hole. 
     
     
       11. The electronic device defined in  claim 9  wherein the depressurization feature comprises a locally weakened portion of the elastomeric balloon that is configured to locally promote rupture of the elastomeric balloon. 
     
     
       12. The electronic device defined in  claim 9  wherein the depressurization feature is configured to receive a fluid passageway structure that is configured to remove pressurized fluid from an interior portion of the elastomeric balloon. 
     
     
       13. An electronic device, comprising: a first conductive structure; a second conductive structure; an inflatable structure that forms an electrical pathway between the first and second conductive structures; and conductive adhesive with which the inflatable structure is attached to the first and second conductive structures. 
     
     
       14. The electronic device defined in  claim 13  wherein the inflatable structure comprises an elastomeric balloon. 
     
     
       15. The electronic device defined in  claim 14  wherein the inflatable structure includes a reservoir. 
     
     
       16. An electronic device comprising: first and second structures separated by at least one gap; an inflatable structure that bridges the gap; and conductive adhesive that attaches the inflatable structure to each of the first and second structures. 
     
     
       17. The electronic device defined in  claim 16  wherein the inflatable structure comprises an elastomeric balloon and wherein the conductive adhesive connects the balloon across the gap to form an environmental seal across the gap.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to zero-force membranes for use in electronic devices. 
     Electronic devices such as portable computers and cellular telephones are often provided with components such as displays and housing structures that need to be electrically shorted to each other. Materials such as conductive foam may be used to form connections between such structures. However, conductive foam may create residual biasing forces. These forces may tend to push components apart following assembly. 
     It would therefore be desirable to provide improved ways in which to form connections such as electrical connections between structures in an electronic device while producing minimal residual forces. 
     SUMMARY 
     An electronic device may include housing structures, electronic components, and other structures. Gaps may be formed between the structures. For example, a gap may be formed between a housing structure and a component that is mounted within the housing structure. 
     One or more membrane structures may be used to bridge the gaps. The membrane structures may be implemented using a zero-force membrane arrangement in which a flexible structure such as a flexible sheet of material or a flexible balloon structure or other defeatable biasing element temporarily biases a membrane against device structures such as housing structures. Following use of the defeatable biasing element to attach the membrane to the device structures, the biasing element may be deactivated (e.g., by puncturing a balloon-based biasing element or by applying heat or other stimulus to the biasing element. The biasing element may also be removed so as to remove the temporary biasing force that is produced by the biasing element. The zero-force membranes that results from removing the force produced by the biasing element may exhibit little to no residual biasing force against the electronic device structures following assembly. The zero-force membranes may be used to form environmental seals between portions of electronic device structures and electrical connections such as grounding connections. 
     The zero-force membranes may be deployed by temporary biasing structures such as defeatable biasing structures that temporarily bias the membranes against device structures. Following formation of a desired connection with a membrane, the temporary biasing structures can be removed to remove the biasing force or may be deactivated (defeated) and left in place. Examples of temporary biasing structures include foam, springs, a material that melts, a shrinkable material, or a material that otherwise yields after biasing the membrane against device structures. A removable inflatable balloon structure may also be used to install a zero-force membrane. 
     Zero-force membranes may be deployed using inflatable structures (e.g., non-removable inflatable structures) that can be deflated by puncturing or by providing pressure relief structures. 
     An inflatable structure may, for example, be formed from an elastomeric balloon that can be pressurized by a fluid such as air. Adhesive such as conductive adhesive may be used in attaching the inflatable structure to the structures in the electronic device. 
     When an inflatable structure is pressurized, the inflatable structure may form an environmental seal that bridges a gap between structures in the electronic device. The inflatable structure may also be pressurized to form an electrical shorting path that bridges the gap. 
     The inflatable structure may be depressurized following assembly to remove residual biasing forces against the structures. The inflatable structure may be depressurized by withdrawing pressurized fluid from the inflatable structure, by providing a hole in the inflatable structure that allows pressurized fluid to escape, by over-pressuring the inflatable structure to form a rupture that allows the fluid to escape, or by otherwise depressurizing the inflatable structure. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device of the type that may be provided with inflatable structures in accordance with an embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of an illustrative inflatable structure in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional end view of an inflatable structure of the type shown in  FIG. 2  in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of an inflatable structure having a coating formed from a layer of adhesive in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an inflatable structure having adhesive-coated regions with which the structure is attached to device structures in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative inflatable structure in an inflated configuration between two opposing device structures in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of the structure of  FIG. 6  following rupture of the structure to release internal pressure in accordance with an embodiment of the present invention. 
         FIG. 8  is a perspective view of a U-shaped inflatable structure in accordance with an embodiment of the present invention. 
         FIGS. 9 ,  10 ,  11 ,  12 , and  13  are cross-sectional views of illustrative inflatable structures in accordance with embodiments of the present invention. 
         FIG. 14  is a cross-sectional view of an illustrative inflatable structure with an opening that is sealed using a layer of adhesive in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional end view of an inflatable structure having multiple overlapping layers of material in accordance with an embodiment of the present invention. 
         FIG. 16  is a top view of an illustrative inflatable structure having a fluid reservoir in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional view of an inflatable structure and associated pressurization and depressurization equipment in accordance with an embodiment of the present invention. 
         FIG. 18  is a perspective view of an illustrative inflatable structure having alternating regions with different types of coatings in accordance with the present invention. 
         FIG. 19  is a flow chart of illustrative steps involved in incorporating inflatable structures into assembled device structures in accordance with an embodiment of the present invention. 
         FIGS. 20 ,  21 , and  22  illustrate how a biasing member such as a foam structure may be used to install a zero-force membrane within a portion of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 23  is a flow chart of illustrative steps involved in incorporating a zero-force membrane into assembled device structures using a removable biasing member such as a foam structure in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with zero-force membranes. The zero-force membranes may be used to form environmental seals between portions of electronic device structures and electrical connections such as grounding connections. The zero-force membranes may exhibit little to no residual biasing force against the electronic device structures following assembly. 
     The zero-force membranes may be deployed by using removable foam or other temporary biasing structures to hold flexible structures such as layers of polymer and adhesive against device structures. Following formation of a desired connection with a membrane, the temporary biasing structures can be removed or the amount of biasing force that is produced by the temporary biasing structures may be reduced or eliminated by deactivating the temporary biasing structures and leaving the temporary biasing structures in place. 
     If desired, zero-force membranes may be formed from inflatable structures. The inflatable structures (inflatable membranes) may include balloon-type structures that allow the inflatable structures to be temporarily pressurized. The inflatable structures may be pressurized to force sidewalls portions of the inflatable structures against adjacent electronic device structures. Adhesive may be used to help hold the sidewalls of the inflatable structures in place. The inflatable structures may include conductive materials such as metal that allow the inflatable structures to form electrical shorting structures between conductive device structures. The inflatable structures may also be used to form environmental seals. 
     Once an inflatable structure has been used to form conductive pathways and/or environmental seals within an electronic device, the inflatable structure may be depressurized. Depressurization operations may be performed by allowing air to escape a pressurized structure through a hole in the structure or a porous structure, by intentionally rupturing the inflatable structure by over-pressuring the structure as part of the inflatable structure installation process, or by removing pressurized air using a needle or other air removal structure. By removing pressure from the inflatable structures, the structures may form zero-pressure connections and/or seals within a device. The minimal pressure exerted by the inflatable structures ensures that the structures will not tend to push apart device structures during normal use of a device following installation of inflatable structures. 
     Temporary biasing structures based on springs, foam, or other defeatable structures may be deactivated following membrane deployment. For example, heat or other stimulus may be applied to deactivate temporary biasing structures. Temporary biasing structures may also be removed following use, if desired. 
     An illustrative electronic device of the type that may be provided with one or more inflatable structures is shown in  FIG. 1 . Electronic device  10  of  FIG. 1  may be a computer, a personal computer, a tablet computer, a cellular telephone, a media player, a gaming device, a navigation device, or other electronic equipment. As shown in the cross-sectional view of device  10  in  FIG. 1 , electronic device  10  may include housing  12 , a display such as display  14 , and internal components such as components  16 . The structures of device  10  may include conductive structures. For example, housing  12  may include one or more conductive metal structures, display  14  may include conductive structures, and other electronic components  16  may include conductive structures. 
     To form electrical connections (e.g., grounding connections or other shorting connections) and/or to form environmental seals between different portions of device  10  (e.g., housing structures  12 , display  14 , and/or other electrical components  16 ), device  10  may be provided with one or more defeatable biasing structures. As shown in  FIG. 1 , for example, device  10  may be provided with inflatable structures  18 . 
     Inflatable structures  18  may be formed from elastomeric balloons and may include one or more coatings or other external structures that fully or partly surround the balloons. The surface of the inflatable structures may be conductive (e.g., for use in arrangements where shorting connections are desired) or insulating (e.g., for use in environmental sealing applications or other configurations in which electrical shorting by the inflatable structures is not desired). 
       FIG. 2  is an exploded perspective view of an illustrative inflatable structure. As shown in  FIG. 2 , inflatable structure  18  may include inflatable balloon structure  20  and, if desired, one or more additional layers of material such as external flexible sheet  22 . Inflatable balloon structure  20  may be formed from an elastomeric substance such as silicone that expands when pressurized. Inflatable balloon structure  20  may be pressurized by forcing a fluid such as a gas (e.g., air, nitrogen, etc.) or a liquid (e.g., water, alcohol, etc.) into the interior of structure  20 . Balloon  20  may be installed within flexible sheet  22  by moving balloon  20  in direction  28  along longitudinal axis  26  or by wrapping sheet  22  around balloon  20 . Optional adhesive  24  may be used to help hold balloon  20  in place within flexible sheet  22  following assembly. 
     Flexible sheet  22  may be formed from one or more sublayers of material. Each of the one or more layers that forms flexible sheet  22  may be formed from polymer or other insulators, metal (e.g., a metal coating formed form metal foil or other structures, a metal mesh, etc.), adhesive (e.g., pressure sensitive adhesive and/or conductive adhesive), and other materials. 
       FIG. 3  is a cross-sectional side view of inflatable structure  18  showing how inflatable balloon  20  may exert pressure outwards in directions  30  when pressurized with gas or other fluid. This may force sheet  22  against adjacent device structures (not shown in  FIG. 3 ). Sheet  22  may be formed from sublayers such as sublayers  32  and  34  (and, optionally, additional sublayers). 
     Inner layer  32  may be, for example, a substrate material. The substrate material may be an insulating material such as a polymer (e.g., polyimide or polyethylene terephthalate) or may be a conductive material (e.g., a metal). To provide sheet  22  with flexibility, layer  32  may be formed from a flexible metal mesh (e.g., a metal fabric). Other conductive structures that may be used to form layer  32  include aluminum foil and a polymer substrate coated with a layer of metal. 
     Outer layer  34  may be an adhesive layer such as a pressure sensitive adhesive layer. Outer layer  34  may be, for example, a conductive adhesive (e.g., in configurations in which inner layer  32  is conductive). 
     In arrangements in which inflatable structure  18  has a conductive surface (e.g., a conductive adhesive formed on a metal mesh, metal foil, or metallized polymer substrate), inflatable structure  18  may be used to form shorting structures between respective conductive structures in device  10  (e.g., between a metal housing part and another metal housing part, between a metal housing structure and an electronic component, between conductive portions of two or more electronic components, etc.). In arrangements in which inflatable structure  18  is free of conductive adhesive and underlying conductive layers, inflatable structure  18  may be used to form seals (e.g., environmental seals that bridge gaps between structures in device  10 ). Seals may be formed to prevent dust and moisture from intruding into internal device regions or to otherwise seal parts together in device  10 . 
     As shown in the cross-sectional view of inflatable structure  18  of  FIG. 4 , structure  18  may be formed by directly coating balloon  20  with adhesive  34 . In this type of configuration, substrate layer  32  need not be used. As shown in  FIG. 4 , inflatable structure  18  may become attached to one or more structure such as structures  38  that are separated by a gap such as gap  39  when inflatable structure  18  is inflated. Structures  38  may be housing structures, display structures, structures associated with other components in device  10  such as other electronic components, or other device structures. 
     Following formation of a seal and/or electrical shorting connection that bridges gap  39  between structures  38  of the type shown in  FIG. 4 , balloon  20  (and therefore inflatable structure  18 ) may be depressurized. Depressurization may eliminate or at least reduce residual pressure from inflatable structure  18  on structures  38 . In the presence of pressure in structures  18 , structures  38  (in the example of  FIG. 4 ) will tend to be forced apart in opposing directions  40 . This may tend to disassemble device  10 , requiring the use of stronger internal structures and structures that are designed to overcome the force in directions  40  and thereby maintain structures  38  in their desired positions. Following depressurization of inflatable structures  18 , however, structures  38  may be maintained in their desired positions without need to provide such additional structures to overcome the biasing force from structures  18 . 
     As shown in  FIG. 5 , inflatable structure  18  may be provided with adhesive  34  that coats only a portion of the surface of inflatable structure  18  (e.g., a portion of balloon  20 ). To facilitate depressurization, inflatable structure  18  may be provided with a depressurization (deflation) feature such as feature  42 . Feature  42  may be a hole that is sufficiently large to allow pressurized fluid to escape from the interior of balloon  20  and that is sufficiently small to allow the release of pressure to be gradual. For example, the hole may be sufficiently small to allow structure  18  to remain pressurized until adhesive bonds have been formed using adhesive  34 . The adhesive bonds need not be fully cured prior to depressurization, but preferably will have developed satisfactory strength to hold inflatable structure  18  in place. Features such a feature  42  may also be formed from permeable membrane regions (e.g., regions of balloon  20  that are configured to gradually allow fluid to escape), a localized scored region or other locally weakened region that is configured to promote localized rupture of balloon  20  (e.g., when balloon  20  exceeds a given pressure), or a port or other structure to allow a hollow needle or other pressurization and depressurization tool to enter and exit balloon  20 . 
       FIG. 6  shows how structure  18  may be pressurized sufficiently to form a seal and/or electrical shorting connection between respective structures  38 .  FIG. 7  shows how structure  18  may appear following application of sufficient internal pressure to rupture structure  18  at depressurization feature  42 . Although one part of structure  18  has ruptured in the example of  FIG. 7 , sufficient structures remain to form a satisfactory environmental seal and/or electrical shorting path bridging the gap between structures  38 . 
     As shown in the perspective view of  FIG. 8 , structure  18  may have a U-shape. In general, structure  18  may have any suitable shape (e.g., a U-shape, an L-shape, a T-shape, a C-shape, a loop-shape, a rectangular loop shape, a solid rectangular shape, an elongated shape, an oval shape, a square shape, a shape with curved edges, a shape with straight edges, a shape with a combination of curved and straight edges, etc. 
       FIGS. 9 ,  10 ,  11 ,  12 , and  13  are cross-sectional views of illustrative inflatable structures  18  showing some of the types of cross-sectional shapes that may be used in implementing an inflatable structure  18 , including a square shape ( FIG. 9 ), a circular shape ( FIG. 10 ), an oval shape ( FIG. 11 ), an L-shape ( FIG. 12 ), and a C-shape ( FIG. 13 ). Other cross-sectional shapes and combinations of these shapes may be used if desired. Combinations of any of these cross-sectional shapes and any of the illustrative outlines described in connection with the example of  FIG. 8  may also be used. 
     As shown in  FIG. 14 , structure  18  may be pressurized by forming a seal along a layer of adhesive  34  on a device structure (e.g., without using a completely enclosed balloon structure). Ends  46  of balloon  20  are not connected to each other. The separation between ends  46  of the material that makes up balloon  20  forms opening  44 . Nevertheless, opening  44  is sealed by virtue of adhesive  34  on structure  38 . 
     In the example of  FIG. 15 , inflatable structure  18  has been formed using a configuration for balloon  20  that includes overlapping structures  20 A and  20 B (sealed using adhesive  34 ′). 
     As shown in  FIG. 16 , inflatable structure  18  may be provided with tube-shaped structures such as rectangular ring-shaped tubular structures  18 L for forming seals and/or electrical shorting paths in corresponding portions of device  10  (e.g. elongated gaps between respective structures  38 ). To ensure that there is sufficient pressure in structure  18  following pressurization (and before depressurization), structure  18  may be provided with a fluid reservoir such as reservoir  18 R. Reservoir portion  18 R and main portion  18 L may be coupled by internal passageways  48 . 
     A system for pressurizing (and, if desired, depressurizing) inflatable structure  18  is shown in  FIG. 17 . As shown in  FIG. 17 , tool  52  may have a fluid source such as source S. Fluid from source S may be injected into the interior of balloon  20  in inflatable structure  18  via hollow needle  56  or other fluid passageway structure. To prepare structure  18  for pressurization using fluid, tool  52  may be moved in direction  50  until needle  56  enters balloon  20 . 
     Structure  18  may be depressurized by removing needle  56  from balloon  20  by moving tool  52  in direction  54  and thereby creating an escape hole for fluid, by extracting fluid through needle  56  using tool  52 , or by pressurizing structure  18  sufficiently that structure  18  ruptures, or by awaiting depressurization through a predefined hole in structure  18 . 
     As shown in  FIG. 18 , the surface of structure  18  may be provided with multiple coatings such as coatings  58  and  60 . Coatings  58  and  60  may include polymers, metals, adhesives, conductive adhesive, etc. As an example, coatings  58  and  60  may be different types of adhesive (e.g., a conductive adhesive and a non-conductive adhesive). The use of different adhesive types may allow formation of adhesive coatings with desired properties (e.g., conduction from the conductive adhesive portions and adhesive strength from strength-optimized adhesive portions). 
       FIG. 19  is a flow chart of illustrative steps involved in using inflatable structures such as inflatable structure  18  during the process of assembling electronic device  10 . 
     At step  62 , inflatable membrane  18  may be installed within an electronic device adjacent to structures  38  (e.g., housing structures, internal device components, conductive structures to be shorted together such as conductive housing structures and/or conductive portions of electrical device components, etc.). 
     At step  64 , equipment such as tool  52  of  FIG. 17  may be used to inject a gas such as air or other fluid into the interior of inflatable structure  18 , thereby pressurizing and inflating structure  18 . The inflation process may force adhesive  34  to make adhesive bonds between portions of structure  18  and portions of structures  38 , bridging one or more gaps between structures  38 . In configurations in which adhesive  34  includes conductive adhesive and/or when portions of structure  18  such as a metallic coating layer, metal fabric structure, or metal layer are formed from conductive structures, the bonds that are formed and the associated portions of structure  18  may form a conductive shorting path between structures  38 . In configurations in which no conductive structures and conductive adhesive is included in structure  18 , the pressurization process may form a non-shorting environmental seal between structures  38 . 
     Following pressurization to form seals and/or conductive paths using structure  18 , structure  18  may be depressurized (step  66 ). Depressurization may be performed by extracting fluid from structure  18  using tool  52 , by over-pressurizing structure  18  (e.g., to cause structure  18  to rupture and thereby release its internal fluid), or by allowing fluid to slowly escape from a hole or porous membrane region in the sidewall of structure  18 . 
     Because structure  18  may be depressurized following installation in device  10 , structure  18  will tend not to generate residual biasing forces on structures  38  following assembly and may therefore serve as a zero-force membrane within device  10 , forming an environmental seal and, if desired, an electrically conductive connecting structure. 
     If desired, zero-force membranes such as may be installed using removable biasing structures. Examples of biasing structures that may be removed from structures  18  after attachment of structures  18  to device structures (e.g., after attachment of membrane  22 ) include foam, a removable inflatable balloon, a spring (e.g., a spring with an oblique or acute L-shaped cross-sectional shape), an elastomer, a material that may be caused to yield (e.g., to facilitate removal following membrane installation) such as plastic, wax, or other material that melts, shrinks, or softens after the application of a chemical, visible or ultraviolet light, or heat stimulus (e.g., heat from inductive heating of the membrane, adjacent structures  38 , or a tool, heat from radiant/conductive heating), a bimetallic strip that generates a removable bias by heating and cooling, or other biasing structure. 
       FIGS. 20 ,  21 , and  22  illustrate how a temporary biasing structure may be used to install a zero-force membrane within a portion of an electronic device. As shown in  FIG. 10 , structure  18  may have an internal biasing structure such as structure  20 F. Structure  20 F may be, for example, a foam structure. The use of foam for structure  20 F is described as an example, but structure  20 F may, in general, be any temporary biasing structure. 
     Membrane layer  22  may include an inner flexible layer covered with an outer layer of adhesive. The inner flexible structure may be formed from a conductive inner flexible structure such as a conductive mesh, sheet of metal foil, or metal-coated polymer or may be formed from a dielectric layer such as a layer of polymer. The outer adhesive layer may be formed from conductive adhesive or non-conducting adhesive and may fully or partly cover layer  22 . 
     Structures  38  may initially be separated, as shown in  FIG. 20 . When structures  38  are moved in directions  68  to compress foam  20 F or when an external tool or other biasing arrangement otherwise causes biasing structure  20 F to force membrane  22  against structures  38 , the outer (adhesive) surface of layer  22  may be pressed against the exposed surface of structures  38 , as shown in  FIG. 21  (e.g., foam  20 F may be compressed and may bias layer  22  outwards against structures  38 ). 
     After the seal between membrane  22  and structures  38  has been formed, foam  20 F or other temporary biasing structure may be removed (e.g., by pulling foam  20 F out in the direction out of the page in the example of  FIG. 21 ). After foam  20 F has been removed, structures  28  (e.g., membrane  22 ) may form a zero-force membrane seal between structures  38 , as shown in  FIG. 22 . 
     If desired, temporary biasing structure  20 F may be left in place following use of the temporary biasing structures to bias the membrane against structures  38  (e.g., biasing structure  20 F may be left in place as shown in the configuration shown in  FIG. 21 ), provided that the temporary biasing structure has been deactivated following use. Deactivating the temporary biasing structure to permanently reduce or eliminate the amount of biasing force that biasing structure  20 F produces may be accomplished by altering the temporary biasing structure using an external tool or using other suitable biasing deactivation techniques. 
     As an example, in a configuration in which temporary biasing structure  20 F has been implemented using foam, the temporary biasing structure may be deactivated after use by applying heat or other stimulus. This may collapse the foam, so that the foam no longer generates significant biasing force on membrane  22 . If, as another example, temporary biasing structure  20 F has been implemented using a spring (e.g., a spring with an oblique or acute L-shaped cross-sectional shape), temporary biasing structure  20 F may be deactivating by over-traveling the spring to remove its biasing efficacy, by applying heat, by moving part of the spring structure relative to other parts of the spring structure, or by applying other bias removal stimulus to the spring. Elastomeric materials or materials such as plastic or wax that are used as temporary biasing structure  20 F may be deactivated by heat (e.g., to cause the material of structure  20 F to soften or otherwise yield and thereby produce less biasing force) or other stimulus. 
     Membrane installation schemes in which some of temporary biasing structure  20 F is removed following membrane installation while some of temporary biasing structure  20 F remains in place following membrane installation may also be used, if desired. For example, temporary biasing structure  20 F may be formed from a structure with multiple materials. One of the materials (e.g., a foam material) may remain in place after use. The other of the materials may be removed after use (e.g., by evaporating the material by application of heat). 
       FIG. 23  is a flow chart of illustrative steps involved in incorporating a zero-force membrane of the type shown in  FIG. 22  into assembled device structures using a temporary biasing member such as structure  20 F ( FIGS. 20 and 21 ) in accordance with an embodiment of the present invention. 
     At step  70 , structures  18  may be mounted in device  10 , as shown in  FIG. 20 . Biasing structures such as temporary biasing structure  20 F is preferably capable of at least temporarily generating a biasing force to attach membrane  22  of structures  18  in device  10  and may be included in structures  18  during installation of structures  18  in the position shown in  FIG. 20 . Biasing structure  20 F may be fully or partly removable or may be a temporary biasing structure that is not to be removed following use. 
     At step  72 , temporary biasing structures  20 F may be used to bias membrane  22  and the adhesive on membrane  22  against the surfaces of structures  38 . The adhesive on membrane  22  attaches membrane  22  to structures  38 , thereby forming a seal and/or an electrical connection between structures  38 . 
     Once the membrane  22  has been installed, temporary biasing structures  20 F may be removed and/or deactivated (step  74 ). In particular, biasing structures  20 F may be deactivated so that the biasing force that is generated by biasing structures  20 F are permanently eliminated or at least reduced (e.g., by application of heat or other suitable stimulus). In configurations in which temporary biasing structures  20 F are removable temporary biasing structures, biasing structures  20 F may be removed from device  10  to remove the biasing forces produced by biasing structures  20 F and thereby ensure that membrane  22  serves as a zero-force membrane and does not generate undesired residual biasing forces on structures  38 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20111031
Publication Date: 20141104
Grant Date: 20141104
Priority Date: 20111031
Inventors: WRIGHT DEREK
UTTERMANN ERIK A.
ROTHKOPF FLETCHER R.
Assignee: APPLE INC
CPC Classifications: [{"code": "Y10T29/49002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 48172196