PATENT DOCUMENT

Publication Number: US-8242390-B2
Application Number: US-55294809-A
Country: US
Kind Code: B2

Title: Dome switch array

Abstract:
An array of domes is constructed from a single sheet of conductive material. For example, several domes can be stamped at a preset distribution within a sheet of metal. The domes can be placed at any suitable position along the surface of the material, including for example at positions defined by the locations of contact pads on a circuit board. The conductive material can be electrically coupled to the circuit board at any suitable location, including for example along an edge of the piece of material. In some embodiments, the sheet of material can extend around the side walls of the circuit board, for example bent around the periphery of the circuit board. The sheet of material can be electrically coupled to the bottom of the circuit board, for example by soldering. This approach may provide a water resistant dome switch, whereby water can be prevented from leaking between the dome and the circuit board.

Claims:
1. An input interface for an electronic device, comprising:
 a circuit board comprising a plurality of contact regions distributed along a contact surface of the circuit board, the circuit board comprising a bottom surface opposite the contact surface; 
 a metal plate comprising:
 a first surface comprising a plurality of domes positioned to match the distribution of the contact regions, wherein the first surface is exposed for a user to press the plurality of domes; and 
 at least one side wall extending substantially orthogonal from the first surface, the at least one side wall extending beyond the bottom surface of the circuit board. 
 
 
     
     
       2. The input interface of  claim 1 , wherein: the at least one side wall is coupled to the bottom surface of the circuit board. 
     
     
       3. The input interface of  claim 2 , wherein:
 the at least one side wall is coupled to the bottom surface of the circuit board around a periphery of the bottom surface of the circuit board. 
 
     
     
       4. The input interface of  claim 2 , further comprising:
 a water-proof joint between the at least one side wall and the bottom surface of the circuit board. 
 
     
     
       5. The input interface of  claim 4 , wherein:
 the water-proof joint comprises a solder joint. 
 
     
     
       6. The input interface of  claim 1 , further comprising:
 a housing operative to contain the circuit board, the housing coupled to the metal plate. 
 
     
     
       7. The input interface of  claim 6 , wherein:
 the housing further comprises an edge extending from a surface of the housing, the edge operative to be positioned in contact with the metal plate. 
 
     
     
       8. A method for assembling an input interface, comprising:
 providing a plurality of contact regions on a first surface of a circuit board, the plurality of contact regions each associated with a switch; 
 aligning a metal plate comprising a plurality of domes with the circuit board, wherein each of the plurality of domes is aligned with one of the plurality of contact regions; and 
 sealing the metal plate to a second surface of the circuit board, the second surface of the circuit board opposite the first surface of the circuit board. 
 
     
     
       9. The method of  claim 8 , further comprising:
 placing a housing around the circuit board; and coupling the housing to the metal plate. 
 
     
     
       10. The method of  claim 9 , wherein: the housing extends beyond the periphery of the metal plate. 
     
     
       11. The method of  claim 9 , wherein: the metal plate extends beyond the periphery of the housing. 
     
     
       12. The method of  claim 8 , wherein sealing further comprises: applying a solder joint between the metal plate and the second surface of the circuit board. 
     
     
       13. The method of  claim 8 , wherein sealing further comprises: sealing the metal plate to the second surface of the circuit board around the periphery of the circuit board. 
     
     
       14. A button assembly, comprising:
 a circuit board comprising a contact pad for at least one switch; and 
 a metal cover forming at least one dome associated with the contact pad, wherein the at least one dome is exposed for a user to press the at least one dome, the cover further forming a wall extending beyond a surface of the circuit board opposite the contact pad such that the contact pad is enclosed in a space defined by the cover and the circuit board. 
 
     
     
       15. The button assembly of  claim 14 , wherein the cover further comprises:
 a first surface comprising the dome, the first surface being substantially in a single plane; and 
 wherein the wall extends from a periphery of the first surface, the wall extending in a different plane than the single plane of the first surface. 
 
     
     
       16. The button assembly of  claim 15 , wherein:
 the wall extends substantially orthogonal from the first surface of the cover. 
 
     
     
       17. The button assembly of  claim 15 , wherein:
 the wall extends substantially around the entirety of the periphery of the first surface. 
 
     
     
       18. The button assembly of  claim 14 , wherein:
 the cover extends along an edge of the circuit board; and 
 the assembly further comprises a water-resistant seal between the cover and a surface of the circuit board. 
 
     
     
       19. The button assembly of  claim 18 , further comprising:
 a water resistant seal between the cover and the surface of the circuit board opposite the surface of the circuit board that comprises the contact pads. 
 
     
     
       20. The button assembly of  claim 19 , further comprising:
 a water resistant seal between the cover and the surface of the circuit board that extends around the entire periphery of the circuit board.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/181,147, filed on May 26, 2009, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This is directed to an array of domes constructed in a cosmetic conductive material for use in a dome switch assembly. In addition, this is directed to a dome for use with a dome switch, where the dome extends around the side edge of the circuit board on which the switch is provided. 
     Users can provide inputs to electronic devices using many different approaches. One common approach can include a dome switch. Using a dome switch, a user can short an electrical circuit to provide a detectable input. The dome switch is typically constructed by placing a conductive dome over a contact pad on a circuit board. When the dome is pressed, the dome can invert such that the inner surface of the dome contacts the contact pad. The dome inversion also provides a tactile ‘click’ that enhances the user&#39;s interaction with the switch. To actuate the dome switch, a user typically presses a cosmetic piece placed over the dome. In response to the user pressing the cosmetic piece, the dome is in turn is depressed and contacts the contact point. 
     Individual dome switches are typically constructed by adhering the domes to the circuit board. For example, an adhesive can be used around the periphery of each dome. As another example, a layer of adhesive material (e.g., a layer of tape) can be placed over the surface of the dome and adhere to circuit board. These approaches, however, are typically applied only to individual domes, and do not ensure a water-tight or water resistant fit for the domes. In particular, water can be introduced between the dome and the conductive pad, thus shorting the dome switch. 
     SUMMARY OF THE INVENTION 
     A sheet of conductive material into which domes are formed is provided for an array of dome switches. The sheet of conductive material can serve as the cosmetic outer surface for the electronic device in which the dome switch array is provided. In some embodiments, the sheet of material, or material for individual domes can be folded over the edge of the circuit board on which the domes are provided, such that the domes are coupled to the underside of the circuit board. 
     Several domes can be constructed in a single piece of conductive material. For example, several domes can be stamped at a preset distribution within a sheet of metal. The domes can be placed at any suitable position along the surface of the material, including for example at positions defined by the locations of contact pads on a circuit board. The conductive material can be electrically coupled to the circuit board at any suitable location, including for example along an edge of the piece of material. Because the entire piece of material is conductive, the edges of each dome need not be electrically coupled to the circuit board to create an electrical circuit between the circuit board, domes, and contact pads. 
     In some embodiments, the conductive material can be finished to serve as a cosmetic outer surface of the electronic device. For example, the conductive material can be polished or a label can be placed on the material. In some embodiments, some or all of the body of the electronic device can be manufactured (e.g., injection molded) around the conductive material such that the domes of the conductive material remain exposed for actuation by the user. 
     In one implementation, the sheet of material can extend around the side walls of the circuit board. For example, the sheet of conductive material can be sized such that it may be bent around the periphery of the circuit board and electrically coupled to the bottom of the circuit board, for example by soldering. This approach may provide a water resistant dome switch, whereby water can be prevented from leaking between the dome and the circuit board. 
    
    
     
       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. 1  is an exploded view of an illustrative electronic device having an array of dome switches in accordance with one embodiment of the invention; 
         FIG. 2  is a perspective view of the illustrative electronic device of claim  1  once assembled in accordance with one embodiment of the invention; 
         FIGS. 3A and 3B  are top and side views of a dome array plate for use with the illustrative electronic device of claim  1  in accordance with one embodiment of the invention; 
         FIG. 4  is a cross-sectional view of an illustrative electronic device having a dome switch in accordance with one embodiment of the invention; 
         FIG. 5  is another cross-sectional view of an illustrative electronic device having a dome switch in accordance with one embodiment of the invention; and 
         FIG. 6  is a schematic view of an electronic device having several dome switches in accordance with one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device can include several input interfaces for detecting inputs provided by a user. In particular, an electronic device can include one or more dome switches exposed to the user.  FIG. 6  is a schematic view of an electronic device having several dome switches in accordance with one embodiment of the invention. Electronic device  600  can include housing  602  for retaining electronic device components, such as circuit board  610 . Individual domes  620  can be mounted on the surface of circuit board  610 , such that a user can invert a dome to provide an input to the electronic device. In particular, the circuit board can include conductive pads distributed on the surface of the circuit board such that upon inverting a dome, the inner surface of the dome contacts the conductive pad and shorts an electrical circuit. To actuate each dome  620 , the electronic device can include a cosmetic component, such as a button, positioned over each dome and operative to provide an inversion force on the dome. 
     Using the approach described in connection with  FIG. 6 , each dome switch is individually mounted to the device, and does not serve as a cosmetic component of the electronic device. To reduce the size required for the electronic device while providing an aesthetically pleasing input interface, several domes can be manufactured in a single piece of conductive material placed over the circuit board of the electronic device.  FIG. 1  is an exploded view of an illustrative electronic device having an array of dome switches in accordance with one embodiment of the invention.  FIG. 2  is a perspective view of the illustrative electronic device of claim  1  once assembled in accordance with one embodiment of the invention. Electronic device  100  can include cover  102  positioned over housing  110  (e.g., as shown in  FIG. 2 ). Cover  102  can be formed from a single piece of conductive material, such as a metal. Cover  102  can include several domes  104  operative to be deformed such that an inner surface of the dome can contact a portion of housing  110  located underneath the dome. To provide an electrical circuit that can be closed by deformation of the dome, housing  110  can include several sets of electrically isolated contact pads  114  and  116 . In one implementation, contact pad  116  can be placed in electrical contact with the periphery of each dome  104 , and contact pad  114  can be positioned opposite the center of the domes. When a dome is depressed, the inner surface of the dome can meet contact pad  114  to close the electrical circuit between contact pads  114  and  116 . In some embodiments, when cover  102  is constructed from a single piece of conductive material, only a single contact pad  116  may be necessary to create an electrical circuit for each dome switch. The single contact pad  116  can be placed at any suitable position along cover  102 , including for example along an edge of the cover. 
     Cover  102  can have any suitable size, cross-section, and number of domes. For example, cover  102  can be constructed from a thin sheet of conductive material into which domes  104  are stamped.  FIGS. 3A and 3B  are top and side views of a dome array plate for use with the illustrative electronic device of claim  1  in accordance with one embodiment of the invention. Cover  300  can include any suitable plate  302  having a distribution of domes for providing inputs to an electronic device. Individual domes  304  can be distributed on cover  300  in any suitable pattern or at any suitable distance from each other, for example in a pattern or distribute set by a circuit board over which the cover is to be placed. In the example shown in  FIGS. 3A and 3B , cover  300  can have three domes  304  regularly and symmetrically distributed on plate  302 . 
     Plate  302  can have any suitable dimensions. In some embodiments, plate  302  can be a substantially rectangular, for example as a 4.0 mm by 27.0 mm rectangle. Plate  302  can have any suitable thickness, including for example a varying thickness. In one implementation, the thickness of domes  304  can be less than that of the other portions of cover  302  to allow the domes to deflect more easily. As another example, domes  304  can have a larger thickness than the other portions of cover  302  to reduce the overall size of the electronic device (e.g., little thickness is needed around the domes because those portions of cover  300  are purely cosmetic). Cover  300  can have any suitable thickness, including for example a thickness in the range of 0.1 mm to 2 mm (e.g., 0.8 mm to 1 mm). 
     In some embodiments, the thickness, size and distribution of each dome  304  can be selected to provide a particular tactile feedback to the user. In particular, as each dome  304  inverts, the user can feel the dome deflect and bounce back upon release. The force required to deflect the dome can be characterized by a click factor, the measurement of which is well known in the art. The domes in cover  300  can have any suitable click ratio, including for example a ratio in the range of 0.03 to 0.6. In some embodiments, the click ratio for the domes can be larger than 0.3. 
     In some embodiments, the plate or sheet of material having the domes can be bent (e.g., at 90 degree angles) such that different domes are on different planes. This can allow, for example, a single sheet of material to be used to provide an input interface along several sides of an electronic device. The plate of conductive material can be bent in any suitable shape, including for example based on aesthetic considerations of the electronic device. 
     The cover having several domes, or individual domes can be coupled to a circuit board using any suitable approach. In some embodiments, the coupling approach selected can provide a water-tight fit.  FIG. 4  is a cross-sectional view of an illustrative electronic device having a dome switch in accordance with one embodiment of the invention. Electronic device  400  can include cover  401  placed over circuit board  410 . Cover  401  can include dome  402  operative to deflect, and extension  404  extending beyond the periphery of dome  402 . Extension  404  can include a portion extending at an angle from the plane defined by the periphery of dome  402 , including for example extending orthogonally away from the dome. Extension  404  can be at any suitable distance from dome  402 , including for example at a distance set by the dimensions of the circuit board  410  over which cover  401  is placed. In some embodiments, extension  404  can extend substantially along the side walls of circuit board  410 . In the example of  FIG. 4 , extension  404  can in addition extend beyond circuit board  410  to provide side walls for the electronic device and a structure for supporting or retaining other electronic device components (e.g., a power supply or other circuitry). In some embodiments, extension  404  can include one or more additional domes placed opposite conductive pads within electronic device  400  for providing inputs. The dome of extension  404  and dome  402  can then be constructed from the same piece of conductive material, but be in different planes or have different orientations. 
     To close electronic device  400 , wall  430  can be coupled to extension  410 . In some embodiments, wall  430  and cover  401  can be constructed from the same material (e.g., a metal) to provide a consistent aesthetically pleasing device. Alternatively, additional components can be placed over one or both of cover  401  and wall  430  (e.g., inject mold plastic around cover  401  and wall  430 ). In some embodiments, the coupling between wall  430  and extension  404  can be a water-tight seal preventing water from shorting the dome switch. To actuate the dome switch, circuit board  410  can include contact pad  412  positioned substantially underneath dome  402 . When dome  402  is inverted, the inner surface of the dome can contact pad  412  and close an electrical circuit. If cover  401  is constructed from an electrically conductive material, cover  401  can be electrically coupled to the bottom surface of circuit board  410 , for example via solder joints  420 , to close to electrical circuit of the dome switch. The solder joint, or other electrically conductive coupling between circuit board  410  and cover  401  can provide a secondary water-tight seal for the dome switch. 
       FIG. 5  is another cross-sectional view of an illustrative electronic device having a dome switch in accordance with one embodiment of the invention. Electronic device  500  can include cover  501  positioned over circuit board  510 . Cover  501  can include dome  502  operative to deflect, and extension  504  extending beyond the periphery of dome  502 . Similar to extension  404  ( FIG. 4 ), extension  504  can include a portion extending at an angle from the plane defined by the periphery of dome  502 , including for example extending orthogonally away from the dome. Extension  504  can be at any suitable distance from dome  502 , including for example at a distance set by the dimensions of the circuit board  510  over which cover  501  is placed. In some embodiments, extension  504  can extend substantially along the side walls of circuit board  510 . In the example of  FIG. 5 , extension  504  can extend a minimal distance beyond the bottom surface of circuit board  510 . 
     To actuate the dome switch, circuit board  510  can include contact pad  512  positioned substantially underneath dome  502 . When dome  502  is inverted, the inner surface of the dome can contact pad  512  and close an electrical circuit. If cover  501  is constructed from an electrically conductive material, cover  501  can be electrically coupled to the bottom surface of circuit board  510 , for example via solder joints  520 , to close to electrical circuit of the dome switch. The solder joint, or other electrically conductive coupling between circuit board  510  and cover  501  can provide a water-tight seal for the dome switch. 
     The electronic device can be closed using any suitable approach. In some embodiments, housing  530  can be placed around circuit board  520  such that housing  530  is coupled to extension  504  of cover  501 . Housing  530  can be manufactured from any suitable material, including for example a metal (e.g., the same conductive material as cover  501 ), a plastic (e.g., injection molded around cover  501  and circuit board  510 ), a composite material, or any other suitable material. In some embodiments, the connection between housing  530  and extension  504  can be substantially water-tight to form a barrier around the dome switch. Alternatively, the connection between housing  530  and extension  504  can include one or more openings, for example for sound waves to propagate to or from a microphone or speaker, while ensuring that solder joint  520  provides a water-tight seal around the dome switch. 
     The above described embodiments of the present invention are presented for purposes of illustration and not of limitation, and the present invention is limited only by the claims which follow.

Metadata:
Filing Date: 20090902
Publication Date: 20120814
Grant Date: 20120814
Priority Date: 20090526
Inventors: PREST CHRISTOPHER
FRAZIER CAMERON
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H13/86", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/86", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2205/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2205/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2231/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49133", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2221/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2221/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2231/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 43218994