PATENT DOCUMENT

Publication Number: US-9272471-B2
Application Number: US-201313864505-A
Country: US
Kind Code: B2

Title: Switch modules with electromagnetic interference shielding structures

Abstract:
An accessory may be provided with a button controller having a microphone and switches. The switches may include dome switch members and metal switch terminals mounted in a switch module housing structure. The switch module housing structure may include one or more recesses in which electrical components are mounted. A conductive backplate may cover the recesses and may be coupled to the switch module housing structure. A conductive film may be attached to the switch module housing structure over the dome switch members. The conductive film and the conductive backplate may form an electromagnetic interference shield around the electrical components in the recesses. The switch module housing structure may include a non-conductive plastic overmolded onto a metal frame or may be formed from a first shot of non-conductive plastic and a second shot of conductive plastic to form an electromagnetic interference shield for the electrical components.

Claims:
What is claimed is: 
     
       1. An apparatus, comprising:
 a switch module having metal switch terminals embedded in a plastic structure having at least one recess; 
 an electrical component mounted on a printed circuit within the at least one recess; 
 at least one dome switch formed from a dome switch member and portions of the switch terminals; 
 a conductive film attached to the switch module over the dome switch member; and 
 a conductive backplate that covers the recess, wherein the conductive film and the conductive backplate together form an electromagnetic interference shield that completely surrounds the electrical component. 
 
     
     
       2. The apparatus defined in  claim 1  wherein the conductive film is coupled to and electrically grounded via the conductive backplate. 
     
     
       3. The apparatus defined in  claim 1  wherein the switch module includes at least a first shot of plastic that has at least one additional recess configured to receive the dome switch member. 
     
     
       4. The apparatus defined in  claim 3  further comprising at least a second shot of plastic overmolded onto the first shot of plastic. 
     
     
       5. The apparatus defined in  claim 1  wherein the switch module comprises a metal frame and wherein the plastic structure is overmolded onto the metal frame. 
     
     
       6. The apparatus defined in  claim 5  wherein the metal frame is welded to the conductive backplate. 
     
     
       7. The apparatus defined in  claim 1  wherein the switch module comprises a U-shaped metal frame member and wherein the U-shaped metal frame member and the plastic structure form an enclosure that completely surrounds the electrical component. 
     
     
       8. An accessory button controller, comprising:
 a conductive enclosure having interior and exterior surfaces; 
 a printed circuit mounted to the interior surface; 
 an electrical component mounted to the printed circuit; and
 a switch module mounted to the exterior surface, wherein the switch module includes metal switch terminals that are electrically coupled to the printed circuit through the conductive enclosure and wherein the conductive enclosure shields the electrical component from electromagnetic interference. 
 
 
     
     
       9. The accessory button controller defined in  claim 8  wherein the conductive enclosure comprises a planar sheet of metal and a U-shaped metal structure, wherein the planar sheet of metal is welded to the U-shaped metal structure. 
     
     
       10. The accessory button controller defined in  claim 9  wherein the printed circuit is mounted to the planar sheet of metal. 
     
     
       11. The accessory button controller defined in  claim 8  wherein the switch module comprises a plastic structure and wherein the switch terminals are embedded in the plastic structure. 
     
     
       12. The accessory button controller defined in  claim 8  wherein the switch module comprises at least one dome switch formed from a dome switch member and portions of the switch terminals. 
     
     
       13. The accessory button controller defined in  claim 12  further comprising a polymer film that covers the dome switch member. 
     
     
       14. A method, comprising:
 with an injection molding tool, insert molding a first shot of non-conductive plastic around metal switch terminals; 
 overmolding a second shot of conductive plastic onto the first shot of non-conductive plastic to form a switch module housing structure having a recess; 
 placing at least one electrical component mounted to a printed circuit within the recess; and 
 attaching the switch module housing structure to a conductive backplate to enclose the at least one electrical component within the recess and to thereby shield the at least one electrical component from electromagnetic interference. 
 
     
     
       15. The method defined in  claim 14  wherein overmolding the second shot of conductive plastic onto the first shot of non-conductive plastic comprises forming a conductive lining on the first shot of non-conductive plastic that surrounds the recess. 
     
     
       16. The method defined in  claim 14  further comprising mounting a dome switch member in a cavity in the first shot of non-conductive plastic. 
     
     
       17. The method defined in  claim 16  further comprising attaching a polymer film to the switch module housing structure to cover the dome switch member. 
     
     
       18. The method defined in  claim 14  wherein the conductive plastic comprises a polymer with a conductive filler and wherein the conductive backplate and the second shot of conductive plastic together form an electromagnetic interference shield that completely surrounds the electrical component.

Description:
BACKGROUND 
     This relates to electronic devices, and more particularly, to accessories for electronic devices. 
     Electronic devices such as computers, media players, and cellular telephones typically contain user interface components that allow these devices to be controlled by a user. It is sometimes desirable to add accessories to electronic devices. For example, a user may desire to plug a headset or adapter accessory into an electronic device to allow the user to listen to audio. 
     Headsets are sometimes provided with buttons and microphones. A headset microphone may be used to pick up a user&#39;s voice during a telephone call. Buttons may be used to control media file playback, to make volume level adjustments during a telephone call, and to issue other commands for the electronic device. Buttons and a microphone may be mounted within a button controller assembly. Microphone signals and button signals may be routed from the button controller assembly to an electronic device using wires in the headset. 
     The designers of accessories and other electronic equipment are challenged with designing parts that are not overly complex or costly and that exhibit satisfactory reliability and performance. For example, it can be challenging to design a button controller assembly that adequately shields electrical components within the button controller assembly from electromagnetic interference without adding undesirable bulkiness to the button controller assembly. 
     It would therefore be desirable to provide improved electronic device accessories such as accessories with button controller and microphone assemblies. 
     SUMMARY 
     An accessory may be provided with a button controller. The button controller may have a switch module that contains switches and electrical components such as a microphone. The switches may be formed from dome switch members and metal switch terminals. The microphone and other electrical components may be mounted in recesses in switch module housing structures. 
     The switch module housing structures may be formed using injection molding operations. For example, switch terminals for the switches may be formed by molding plastic around switch terminal structures. Switches may then be formed using dome switch members and the switch terminals. The switch module housing structures may be mounted to a conductive backplate. 
     A conductive thin film may be attached to the switch module housing structure over the dome switch members. The conductive film and conductive backplate may form an electromagnetic interference shield that surrounds the electrical components in the button controller. 
     In another suitable embodiment, the switch module housing structure may be formed from a first shot of non-conductive plastic and a second shot of conductive plastic. The conductive plastic and a conductive backplate may form an electromagnetic interference shield around the electrical components in the button controller. 
     In another suitable embodiment, the switch module housing structure may be formed from a shot of non-conductive plastic that is insert molded around the metal switch terminals and a metal frame. The metal frame and a conductive backplate may form an electromagnetic interference shield around the electrical components in the button controller. 
     In another suitable embodiment, a conductive enclosure may have interior and exterior surfaces. A printed circuit on which an electrical component is mounted may be mounted to the interior surface of the conductive enclosure. A switch module may be mounted to the exterior surface of the conductive enclosure and may include metal switch terminals that are electrically coupled to the printed circuit through the conductive enclosure. The conductive enclosure may include a U-shaped metal structure that is welded to a planar sheet of metal. 
     Further features, their nature, and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of a system including an electronic device and associated accessory in accordance with an embodiment. 
         FIG. 2  is a wiring diagram for an illustrative accessory such as a pair of headphones with a button controller that has switches and a microphone in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of an illustrative button controller assembly for an accessory in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a first shot of non-conductive plastic and a second shot of conductive plastic in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a shot of non-conductive plastic that is overmolded onto a metal frame having engagement features in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a shot of non-conductive plastic having engagement features that is overmolded onto a metal frame in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a shot of non-conductive plastic and a U-shaped metal frame having engagement features in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a shot of non-conductive plastic having engagement features and a U-shaped metal frame in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of illustrative button controller structures in which a switch module housing structure is formed from a double-shot of non-conductive plastic and is lined with a conductive coating in accordance with an embodiment. 
         FIG. 10  is a cross-sectional side view of illustrative button controller structures in which a switch module is mounted to a conductive enclosure that surrounds an electrical component mounted to a printed circuit in accordance with an embodiment. 
         FIG. 11  is a flow chart of illustrative steps involved in assembling button controller structures of the type shown in  FIGS. 5 and 6  in accordance with an embodiment. 
         FIG. 12  is a flow chart of illustrative steps involved in assembling button controller structures of the type shown in  FIG. 4  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic components such as microphones and buttons may be used in a wide range of applications. For example, microphones and buttons may be used to form a button controller for a headset or other accessory. Button structures and microphone structures may, in general, be used in any suitable system. Button controller assemblies that are suitable for use in accessories such as electronic device headsets are sometimes described herein as an example. 
     An illustrative system in which an accessory may be used with an electronic device is shown in  FIG. 1 . As shown in  FIG. 1 , electronic device  10  may be coupled to an accessory such as headset  12  by plugging plug  16  of accessory  12  into jack  14  of electronic device  10 . 
     Electronic device  10  may be a computer such as a desktop computer, tablet computer, or laptop computer. Device  10  may also be a handheld electronic device such as a cellular telephone or media player, a tablet device, other portable electronic devices, or any other electronic equipment. Headset  12  may have speakers  18  and controller  22 . Controller  22  may have buttons and may therefore sometimes be referred to as a button controller or button controller assembly. Button controller  22  and speakers  18  may be coupled to device  10  using cable  20  (e.g., a three-wire or four-wire headset cable). Button controller  22  may, if desired, include one or more microphones. For example, button controller  22  may include a voice microphone that is used by a user of device  10  and headset  12  during a telephone call (e.g., to pick up the user&#39;s voice). 
     Button controller  22  may include buttons such as buttons  24 ,  26 , and  28 . There may, in general, be any suitable number of buttons in button controller  22  (e.g., one or more buttons, two or more buttons, three or more buttons, etc.). With one suitable arrangement, which is sometimes described herein as an example, button controller  22  may include three buttons. These buttons may be used to issue commands for device  10 . Examples of commands that may be issued for device  10  using the buttons of button controller assembly  22  include stop, forward, and reverse commands, volume up and down commands, telephone call control commands, etc. 
     A wiring diagram of an illustrative accessory such as headset  12  of  FIG. 1  is shown in  FIG. 2 . As shown in  FIG. 2 , headset  12  may have wires in cables  20  that interconnect left speaker  18  (LS), right speaker  18  (RS), plug  16 , and button controller  22 . Two ground lines (G and G 2 ) may be coupled to a ground terminal in plug  16 . A microphone line (M), left speaker line (L), and right speaker line (R) may be coupled to a microphone terminal, left speaker terminal, and right speaker terminal in plug  16 , respectively. Ground line G 2  and microphone line M may terminate on terminals in button controller  22 . Ground line G and speaker line L may pass through the housing of button controller  22  to couple to speaker terminals in left speaker LS. Right speaker RS may have terminals that are coupled between right speaker line R and ground speaker line G. 
     The configuration of  FIG. 2  in which button controller  22  is located on cable  20  between left speaker  18  and plug  16  is merely illustrative. If desired, button controller  22  may be located on cable  20  between right speaker  18  and plug  16 . 
     A cross-sectional side view of structures in button controller  22  is shown in  FIG. 3 . As shown in  FIG. 3 , button controller  22  may have a dome switches formed from dome switch members such as dome switch members  30 . Each dome switch member may contact portions of terminal structures such a terminal structures  32 . Terminal structures  32  may be formed from metal and may be soldered to circuitry such as components  34  on printed circuit board  36  and to wires such as wires  38  in cable  20  using solder  40 . Dome switch members  30  may be received within recesses  48  in switch module housing structure  46 . During operation, dome switch members  30  may be compressed by a user. When a dome switch member is compressed in this way, metal on the dome switch member can short together a corresponding pair of switch terminal structures (i.e., each dome switch is formed from a corresponding dome switch member  30  and portions of associated terminals structures  32 ). 
     Flexible sheet  42  may cover dome switch members  30 . Flexible sheet  42  may be used to hold dome switch members  30  in place while also providing a barrier structure for preventing moisture and other environmental contaminants from entering button controller  22 . Structures  44  may be formed from a material such as epoxy and may be used to create a structure against which an overlying plastic button member may bear when actuating the switches formed by dome switch members  30 . Housing structure  46  may have upper recesses such as dome switch member recesses  48  for receiving dome switch members  30  and may have lower recesses such as lower recesses  50  for receiving components such as a microphone (MIC) and other electrical components  34  on printed circuit board  36 . A planar member such as a sheet of plastic or metal such as backplate  51  may be used to cover recesses such as recesses  50  on the rear of structures  46 . 
     Components such as components  34  on printed circuit  36  may include one or more noise cancelling microphones. For example, a voice microphone in button controller  22  may have an associated noise cancellation microphone that picks up ambient noise in the vicinity of the voice microphone. The earbuds or other speakers in an accessory may also have noise cancellation microphones. For example, left and right speakers  18  of  FIG. 2  may each have an external noise cancellation microphone on an outer surface of the speaker. In addition to the external noise cancellation microphone or instead of the external noise cancellation microphone, each speaker  18  may have an internal noise cancellation microphone on an interior surface of the speaker (adjacent to the ear). 
     Components  34  on printed circuit  36  may include digital audio processing circuitry for performing digital signal processing on audio signals. For example, an audio signal processor in button controller  22  may be used to remove noise from the audio voice signal picked up by voice microphones in button controller  22 . Electrical paths in cable  20  may be used in conveying digital audio data between accessory  12  and electronic device  10  (e.g., pulse-code-modulation encoded digital audio data). 
     Care must be taken to ensure that digital signal processing circuitry is properly shielded from electromagnetic interference. Without adequate electromagnetic shielding, radiated emissions from integrated circuits within accessory  12 , radiated emissions from outside sources, and/or electrostatic discharge can interfere with and disrupt signal processing. 
     Electromagnetic shielding structures may be incorporated into button controller  22 . The electromagnetic shielding structures may fully or partially surround components  34  on printed circuit  36 . The electromagnetic shielding structures may, for example, be incorporated into housing structure  46  and/or may be incorporated into flexible sheet  42 . Incorporating electromagnetic shielding structures into the structures that make up button controller  22  may eliminate the need for separate shielding structures that would add undesirable bulkiness to button controller  22 . 
     In the illustrative example of  FIG. 3 , flexible sheet  42  is formed from a conductive film that wraps around switch module housing structure  46  and is coupled to backplate  51 . Backplate  51  may also be conductive (e.g., backplate  51  maybe formed from metal or conductive plastic) and may be used to electrically ground conductive film  42 . Conductive film  42  and conductive backplate  51  together form an electromagnetic shield that completely surrounds components  34  on printed circuit  36 . 
     Conductive film  42  may, for example, be a metalized thin film formed from a layer of metal that is laminated to a polymer substrate, a layer of metal that is taped to a polymer substrate using adhesive, a metal coating that is sputtered or deposited onto a polymer substrate, a layer of metal that is heat bonded to a polymer substrate (e.g., using a heat press), and/or may include other conductive materials or structures. If desired, other suitable fabrication processes may be used to form conductive film  42 . 
     Conductive film  42  may be flexible such that, when a user presses an overlying plastic button member above structure  44 , structure  44  deforms flexible conductive film  42 , which in turn deforms dome switch members  30  and actuates the switches formed by dome switch members  30 . Conductive film  42  may also form a barrier structure that moisture-seals button controller  22  and prevents other environmental contaminants from entering button controller  22 . 
     Multiple injection-molded plastic structures (sometimes referred to as “shots” of plastic) may be used in forming button controller structures. For example, housing structure  46  may be formed using first and second shots of plastic. The first shot of plastic may be injected around terminal structures  32  and may be used to electrically insulate terminal structures  32  from each other. The second shot of plastic may be overmolded onto the first shot of plastic and may be used to cover any exposed portions of terminal structures  32 . The first and second shots of plastic may together form switch module housing structure  46 . 
     In the illustrative example of  FIG. 3 , components  34  are electromagnetically shielded by conductive film  42  and backplate  51 . With this type of configuration, housing structures  46  need not include any conductive materials for shielding components  34 . Housing structures  46  may, for example, be formed from non-conductive plastics such as liquid crystal polymers, thermoplastic synthetic resins such as polyamide, glass-filled polymers, other non-conductive plastics, or a combination of any two or more of these non-conductive materials. 
     In another suitable embodiment, electromagnetic shielding structures may be incorporated into housing structures  46 . This type of configuration is shown in  FIG. 4 . As shown in  FIG. 4 , housing structures  46  include a non-conductive portion such as non-conductive housing structure  46 NP and a conductive housing structure such as conductive housing structure  46 CP. Non-conductive housing structure  46 NP may be formed from a non-conductive plastic such as liquid crystal polymer, thermoplastic synthetic resin such as polyamide, glass-filled polymer, and/or other non-conductive plastic. Conductive housing structure  46 CP may be formed from a conductive plastic such as a polymer with a conductive filler (e.g., carbon black filler, metallic fibers, etc.). 
     Housing structures  46  may, for example, be formed from a two-shot injection molding process. A first shot of non-conductive resin may be injected around electrical terminals  32  and may be used in forming non-conductive housing portion  46 NP. A second shot of conductive resin may be overmolded onto non-conductive housing structure  46 NP and may be used in forming conductive housing structure  46 CP. As shown in  FIG. 4 , conductive plastic  46 CP forms a conductive lining that surrounds recess  50  in plastic structure  46 NP. 
     Non-conductive housing structure  46 NP may be formed with engagement structures such as engagement structures  52  (sometimes referred to as snap features). Engagement structures  52  may be used in mounting switch module housing structure  46  in a button controller housing. For example, engagement structures  52  may snap into place within a button controller housing and may hold switch module housing structure  46  and other switch module structures in place within the button controller housing. 
     As shown in  FIG. 4 , conductive housing structure  46 CP is formed on an interior surface of non-conductive portion  46 NP and partially surrounds components  34  on printed circuit  36 . Conductive housing structure  46 CP is coupled to and electrically grounded by backplate  51 . Conductive housing structure  46 CP may be laser welded to backplate  51 , may be coupled to backplate  51  using a conductive adhesive, or may otherwise be electrically coupled to backplate  51 . Backplate  51  may be formed from a conductive material such as metal or conductive plastic. With this type of configuration, injection-molded conductive plastic housing structure  46 CP and conductive backplate  51  together form an electromagnetic shield that completely surrounds components  34  on printed circuit  36 . 
     Because components  34  are adequately shielded from electromagnetic interference by conductive plastic housing structure  46 CP and backplate  51 , flexible film  42  need not be conductive. Flexible film  42  may be formed from a non-conductive polymer such as polyethylene terephthalate (PET) or other suitable non-conductive flexible films. The non-conductive polymer film may be used to hold dome switch members  30  in place while also providing a barrier structure for preventing moisture and other environmental contaminants from entering button controller  22 . This is, however, merely illustrative. If desired, flexible film  42  may be formed from a conductive material. 
     In another suitable embodiment, electromagnetic shielding structures are incorporated into switch module housing structure  46  using a metal frame structure. This type of configuration is shown in  FIG. 5 . As shown in  FIG. 5 , housing structure  46  includes non-conductive plastic housing structure  46 NP and metal frame structure  46 M. Non-conductive housing structure  46 NP may be formed from a non-conductive plastic such as liquid crystal polymer, thermoplastic synthetic resin such as polyamide, glass-filled polymer, and/or other non-conductive plastic. Metal frame structure  46 M (sometimes referred to as a metal housing structure) may be formed from metal material such as sheet metal or other metal material. Metal frame  46 M may include engagement features  52  for mounting switch module housing  46  and other switch module structures into a button controller housing for button controller  22 . If desired, engagement features  52  may be metal snap structures that are laser welded onto metal housing portion  46 M. 
     Housing structure  46  may, for example, be formed using an insert-molding process in which non-conductive molten plastic  46 NP is injected into a mold that includes electrical terminals  32  and metal frame structure  46 M. In other words, non-conductive plastic housing structure  46 NP may be insert-molded around electrical terminals  32  and metal frame  46 M. 
     As shown in  FIG. 5 , metal frame  46 M partially surrounds components  34  on printed circuit  36 . Metal frame  46 M is coupled to and electrically grounded by backplate  51 . Metal frame  46 M may be laser welded to backplate  51 , may be coupled to backplate  51  using a conductive adhesive, or may otherwise be electrically coupled to backplate  51 . Backplate  51  may be formed from a conductive material such as metal or conductive plastic. With this type of configuration, metal frame  46 M and conductive backplate  51  together form an electromagnetic shield that substantially surrounds components  34  on printed circuit  36 . 
     As shown in  FIG. 5 , the electromagnetic shield formed by metal frame  46 M and backplate  51  may include a gap such as gap  54  having a diameter D 1 . Diameter D 1  of opening  54  in the electromagnetic shield (sometimes referred to as an aperture) may be sufficiently small such that components  34  are adequately shielded from electromagnetic interference. In this type of scenario, flexible film  42  need not be formed from conductive material. Flexible film  42  may instead be formed from a non-conductive flexible polymer such as PET (as an example). 
     This is, however, merely illustrative. If desired, flexible film  42  may be formed from conductive material and may form an electromagnetic interference shield that covers gap  54 . With this type of configuration, metal frame  46 M, conductive backplate  51 , and flexible conductive film  42  may together form an electromagnetic shield that completely surrounds components  34 . Conductive film  42  may be grounded via metal frame  46 M and conductive backplate  51 . 
     The configuration of  FIG. 5  in which metal structure  46 M forms an exterior surface of housing structure  46  and includes engagement features  52  is merely illustrative. If desired, non-conductive housing structure  46 NP may form an exterior surface for housing structure  46  and may include engagement features  52 . This type of configuration is shown in  FIG. 6 . As shown in  FIG. 6 , housing structure  46  includes non-conductive plastic housing structure  46 NP and metal frame structure  46 M. Non-conductive housing structure  46 NP may be formed from a non-conductive plastic such as liquid crystal polymer, thermoplastic synthetic resin such as polyamide, glass-filled polymer, and/or other non-conductive plastic. Metal frame  46 M may be formed from metal material such as sheet metal or other metal material. Non-conductive housing structure  46 NP may be molded to include engagement features  52  for mounting switch module housing  46  and other switch module structures into a button controller housing for button controller  22 . 
     Housing structure  46  may, for example, be formed using an insert-molding process in which non-conductive molten plastic  46 NP is injected into a mold that includes electrical terminals  32  and metal frame structure  46 M. In other words, non-conductive plastic housing structure  46 NP may be insert-molded around electrical terminals  32  and metal frame  46 M. 
     As shown in  FIG. 6 , metal frame  46 M partially surrounds components  34  on printed circuit  36 . Metal frame  46 M is coupled to and electrically grounded by backplate  51 . Metal frame  46 M may be laser welded to backplate  51 , may be coupled to backplate  51  using a conductive adhesive, or may otherwise be electrically coupled to backplate  51 . Backplate  51  may be formed from a conductive material such as metal or conductive plastic. With this type of configuration, metal frame  46 M and conductive backplate  51  together form an electromagnetic shield that substantially surrounds components  34  on printed circuit  36 . 
     As shown in  FIG. 6 , the electromagnetic shield formed by metal frame  46 M and backplate  51  may include a gap such as gap  54  having a diameter D 2 . Diameter D 2  of gap  54  in the electromagnetic shield may be sufficiently small such that components  34  are adequately shielded from electromagnetic interference. In this type of scenario, flexible film  42  need not be formed from conductive material. Flexible film  42  may instead be formed from a non-conductive flexible polymer such as PET (as an example). In configurations where flexible film  42  is formed from a non-conductive material, flexible film  42  need not wrap all the way around housing structure  46  to couple to backplate  51 . 
     This is, however, merely illustrative. If desired, flexible film  42  may be formed from conductive material and may form an electromagnetic interference shield that covers gap  54 . With this type of configuration, metal frame  46 M, conductive backplate  51 , and flexible conductive film  42  may together form an electromagnetic interference shield that completely surrounds components  34 . Conductive film  42  may wrap around housing structures  46  and may be coupled to and electrically grounded by conductive backplate  51 . If desired, openings may be formed in flexible film  42  over engagement features  52  so that engagement features  52  are exposed and able to snap into place within the button controller housing for button controller  22 . 
     In another suitable embodiment, electromagnetic shielding structures that are incorporated into housing structure  46  may include a U-shaped metal frame structure. This type of configuration is shown in  FIG. 7 . As shown in  FIG. 7 , housing structure  46  includes non-conductive plastic housing structure  46 NP and metal structure  46 M. Non-conductive housing structure  46 NP may be formed from a non-conductive plastic such as liquid crystal polymer, thermoplastic synthetic resin such as polyamide, glass-filled polymer, and/or other non-conductive plastic. Metal frame  46 M may be formed from metal material such as sheet metal or other metal material. Engagement features  52  such as metal snap structures  52  may be mounted to the exterior surface of metal frame  46 M (e.g., metal snap structures  52  may be laser welded onto the surface of metal frame  46 M). 
     Non-conductive housing structure  46 NP may, for example, be formed using an insert-molding process in which non-conductive molten plastic  46 NP is injected into a mold that includes electrical terminals  32 . In other words, non-conductive plastic housing structure  46 NP may be insert-molded around electrical terminals  32 . 
     Following insert-molding non-conductive housing portion  46 NP, non-conductive housing portion  46 NP may be assembled with U-shaped metal frame  46 M to form switch module housing structure  46 . As shown in  FIG. 7 , U-shaped metal frame  46 M partially surrounds components  34  on printed circuit  36 . The electromagnetic shield formed by metal frame  46 M may include a gap such as gap G 1 . Flexible film  42  may be formed from a conductive material and may be formed over an upper surface of housing structure  46  to cover gap G 1 . Flexible film  42  is formed on the surface of non-conductive housing structure  46 NP and wraps around housing structure  46  to couple to metal frame  46 M. Flexible conductive film  42  and metal frame  46 M together form an electromagnetic shield that completely surrounds components  34  on printed circuit  36 . 
     With the configuration shown in  FIG. 7 , an additional backplate structure such as backplate  51  of  FIG. 3  may not be required because planar portion  53  of metal frame  46 M forms a backplate structure for button controller  22 . 
     The configuration of  FIG. 7  in which metal structure  46 M forms an exterior surface of housing structure  46  and includes engagement features  52  is merely illustrative. If desired, non-conductive housing structure  46 NP may form an exterior surface for housing structure  46  and may include engagement features  52 . This type of configuration is shown in  FIG. 8 . As shown in  FIG. 8 , housing structure  46  includes non-conductive plastic housing structure  46 NP and U-shaped metal frame structure  46 M. Non-conductive housing structure  46 NP may be formed from a non-conductive plastic such as liquid crystal polymer, thermoplastic synthetic resin such as polyamide, glass-filled polymer, and/or other non-conductive plastic. Metal frame  46 M may be formed from metal material such as sheet metal or other metal material. Non-conductive housing structure  46 NP may be molded to include engagement features  52  for mounting switch module housing  46  and other switch module structures into a button controller housing for button controller  22 . 
     Non-conductive housing structure  46 NP may, for example, be formed using an insert-molding process in which non-conductive molten plastic  46 NP is injected into a mold that includes electrical terminals  32 . In other words, non-conductive plastic housing structure  46 NP may be insert-molded around electrical terminals  32 . 
     Following insert-molding non-conductive housing portion  46 NP, non-conductive housing portion  46 NP may be assembled with U-shaped metal frame  46 M to form housing structure  46 . As shown in  FIG. 8 , U-shaped metal frame  46 M partially surrounds components  34  on printed circuit  36 . The electromagnetic shield formed by metal frame  46 M may include a gap such as gap G 2 . Flexible film  42  may be formed from a conductive material and may be formed over an upper surface of housing structure  46  to cover gap G 2 . 
     Flexible film  42  is formed on the surface of non-conductive housing structure  46 NP and wraps around housing structure  46  to couple to metal frame  46 M. Flexible film  42  and metal frame  46 M together form an electromagnetic interference shield that completely surrounds components  34  on printed circuit  36 . If desired, openings may be formed in flexible film  42  over engagement features  52  so that engagement features  52  are exposed and able to snap into place within the button controller housing for button controller  22 . 
     In another suitable embodiment, electromagnetic shielding structures in button controller  22  may include a conductive coating that is formed on a surface of housing structure  46  using a deposition tool. This type of configuration is shown in  FIG. 9 . As shown in  FIG. 9 , housing structure  46  includes non-conductive housing portions  46 NP and  46 NP′. Similar to the configuration described in connection with  FIG. 3 , housing structures  46  of  FIG. 9  may be formed using a double-shot injection molding process. A first shot of non-conductive plastic  46 NP may be injected around terminal structures  32  and may be used to electrically insulate terminal structures  32  from each other. A second shot of non-conductive plastic  46 NP′ may be overmolded onto non-conductive plastic housing structure  46 NP and may be used to cover any exposed portions of terminal structures  32 . 
     A conductive coating such as conductive coating  56  may be formed on the surface of housing structure  46 . In the illustrative example of  FIG. 9 , conductive coating  56  is formed on an interior surface of housing structure  46  (e.g., on an interior surface of non-conductive housing portion  46 NP′) and forms a conductive lining that surrounds recess  50  in housing structure  46 . This is, however, merely illustrative. If desired, conductive coating  56  may be formed on an exterior surface of housing structure  46  (e.g., on an exterior surface of non-conductive housing portion  46 NP). 
     Conductive coating  56  may be deposited on the surface of housing structure  46  using evaporation, sputtering, spraying, dipping, other physical vapor deposition techniques, or other suitable techniques for applying conductive coatings to the surface of housing structure  46 . Conductive coating  56  may be formed from copper, gold, aluminum, other metals, a combination of any two or more of these metals, etc. 
     As shown in  FIG. 9 , conductive coating  56  partially surrounds components  34  on printed circuit  36  and is coupled to conductive backplate  51 . Conductive coating  56  and conductive backplate  51  together form an electromagnetic shield that completely surrounds components  34  on printed circuit  36 . Because components  34  are adequately shielded from electromagnetic interference by conductive coating  56  and conductive backplate  51 , flexible film  42  need not be conductive. Flexible film  42  may be formed from a non-conductive polymer such as polyethylene terephthalate (PET) or other suitable non-conductive flexible films. This is, however, merely illustrative. If desired, flexible film  42  may be formed from a conductive material. 
     In another suitable embodiment, conductive backplate  51  is interposed between non-conductive plastic housing structure  46 NP and metal frame structure  46 M. This type of configuration is shown in  FIG. 10 . As shown in  FIG. 10 , dome switch member is mounted in recess  48  in non-conductive switch module housing structure  46 NP. Non-conductive housing structure  46 NP is mounted to a first surface such as upper surface  51 U of conductive backplate  51 . Printed circuit  36  is mounted to an opposing surface such as lower surface  51 L of conductive backplate  51 . Components  34  are mounted on printed circuit  36 . 
     As shown in  FIG. 10 , electrical terminals  32  pass through backplate  51  to form an electrical connection with circuitry on printed circuit  36 . An insulating material may be interposed between terminals  32  and conductive backplate  51  (e.g., rubber, foam, plastic, and/or other suitable dielectric material) and may be used to electrically insulate terminals  32  from backplate  51 . 
     A metal frame structure such as U-shaped metal frame structure  46 M is coupled to lower surface  51 L of backplate  51  and partially surrounds components  34  on printed circuit  36 . Metal frame  46 M may, for example, be laser welded to lower surface  51 L of backplate  51 . Metal frame  46 M and backplate  51  together form a conductive enclosure that completely surrounds components  34  and shields components  34  from electromagnetic interference. As shown in  FIG. 10 , printed circuit  36  is mounted to an interior surface of the conductive enclosure (e.g., to lower surface  51 L of backplate  51 ), whereas switch module housing structures  46 NP are mounted to an exterior surface of the conductive enclosure (e.g., to upper surface  51 U of backplate  51 ). 
     A flexible film such as flexible film  42  is attached to the upper surface of switch module housing  46 NP and is used to hold dome switch members  30  in place within recess  48 . Flexible film  42  may also provide an environmental seal that prevents moisture and other contaminants from entering button controller  22 . Because components  34  are completely shielded from electromagnetic interference using backplate  51  and metal frame  46 M, flexible film  42  need not be conductive. Flexible film  42  may, for example, be formed from a non-conductive polymer such as polyethylene terephthalate (PET) or other suitable non-conductive flexible films. This is, however, merely illustrative. If desired, flexible film  42  may be formed from a conductive material. 
       FIG. 11  is a flow chart of illustrative steps involved in assembling a switch module of the type shown in  FIGS. 5 and 6  for a button controller such as button controller  22 . At step  202 , an injection molding tool may be used to insert mold plastic for structures  46 NP of  FIGS. 5 and 6  over metal switch terminal structures  32  and metal frame structure  46 M. The insert-molding tool may have a mold cavity configured to form molded non-conductive plastic structure  46 NP of  FIGS. 5 and 6 . Electrical terminal structures  32  and metal frame structure  46 M may be located within the mold cavity such that, when plastic structure  46 NP hardens following insert-molding, plastic structure  46 NP is mechanically bonded to electrical terminal structures  32  and metal frame  46 M. Non-conductive plastic housing structure  46 NP and metal frame  46 M may together form switch module housing structure  46 . 
     To form the switch module housing shown in  FIG. 5 , metal frame  46  includes engagement features  52  (e.g., metal structures that are laser welded to metal frame  46 ) and forms an exterior surface of switch module housing  46 . To form the switch module housing shown in  FIG. 6 , non-conductive plastic structure  46 NP is molded with engagement features  52  and forms an exterior surface of switch module housing  46 . 
     At step  204 , metal frame structure  46 M may be attached to a conductive backplate such as conductive backplate  51 . This may include, for example, laser welding metal frame  46 M to conductive backplate  51 . A printed circuit may be mounted on backplate  51  such that, when frame  46 M is attached to backplate  51 , components  34  are enclosed within recess  50  in switch module housing structure  46  and are completely surrounded by switch module housing structure  46  and backplate  51 . Metal frame  46 M and conductive backplate  51  may together form an electromagnetic interference shield that substantially surrounds components  34 . 
     During the operations of step  204 , switch module structures such as dome switch members  30  may be installed in recesses such as recesses  48  in housing  46  and film  42  may be used to cover dome switch members  30  and recesses  48 , thereby forming a switch module for use in button controller  22 . If desired, flexible film  42  may be a conductive film that provides electromagnetic interference shielding. Flexible film  42 , metal frame  46 M, and conductive backplate  51  may together form an electromagnetic interference shield that completely surrounds components  34 . 
       FIG. 12  is a flow chart of illustrative steps involved in assembling a switch module of the type shown in  FIG. 4  for a button controller such as button controller  22 . At step  206 , an injection molding tool may be used to insert-mold a first shot of non-conductive plastic around electrical terminal structures  32 . The injection molding tool may have a mold cavity configured to form plastic housing portion  46 NP of  FIG. 4 . Features such as dome switch member recesses  48 , component recesses  50 , and engagement features  52  may, if desired, be incorporated into plastic structures  46 NP. 
     At step  208 , the injection molding tool may be used to insert mold a second shot of conductive plastic  46 CP onto the first shot of non-conductive plastic  46 NP. Conductive plastic  46 CP may form a conductive lining that surrounds recesses  50  in plastic structure  46 NP. If desired, conductive plastic  46 CP may be formed on an exterior surface of non-conductive plastic  46 NP. The embodiment in which conductive plastic  46 CP forms a conductive lining on an interior surface of non-conductive plastic  46 NP is merely illustrative. 
     Because conductive plastic  46 CP is molded over non-conductive plastic  46 NP, conductive plastic  46 CP is mechanically bonded to non-conductive plastic  46 NP. Conductive plastic structure  46 CP and non-conductive plastic structure  46 NP may together form switch module housing structure  46 . 
     At step  210 , conductive housing structure  46 CP may be attached to a conductive backplate such as conductive backplate  51 . A printed circuit may be mounted on backplate  51  such that, when conductive plastic  46 CP is attached to backplate  51 , components  34  are enclosed within (i.e., completely surrounded by) switch module housing structure  46  and backplate  51 . Conductive plastic housing structure  46 CP and conductive backplate  51  may together form an electromagnetic shield that completely surrounds components  34 . 
     During the operations of step  212 , switch module structures such as dome switch members  30  may be installed in recesses such as recesses  48  and film  42  may be used to cover dome switch members  30  and recesses  48 , thereby forming a switch module for use in button controller  22 . Flexible film  42  may be formed from a non-conductive polymer such as polyethylene terephthalate (PET) or other suitable non-conductive flexible films. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20130417
Publication Date: 20160301
Grant Date: 20160301
Priority Date: 20130417
Inventors: COLAHAN IAN P.
STIEHL KURT R.
Assignee: APPLE INC
CPC Classifications: [{"code": "B29C45/1671", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K9/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C45/1671", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C45/14639", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C70/882", "inventive": true, "first": true, "tree": "[]"}, {"code": "B29K2995/0005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K9/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29K2995/0007", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2995/0005", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14639", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/036", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/008", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14639", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K9/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2995/0007", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2239/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2995/0007", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C70/882", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2223/008", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/036", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0043", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K9/0045", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29K2995/0005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2239/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R5/033", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/1671", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 51728833