PATENT DOCUMENT

Publication Number: US-8729414-B2
Application Number: US-201213731540-A
Country: US
Kind Code: B2

Title: Button assembly with inverted dome switch

Abstract:
A portable electronic device may have an inverted dome switch assembly. The switch assembly may have an inverted dome that has a base and a conductive underside. The base may be attached to a button member. Two electrical contacts in the button member may face the conductive underside. Corresponding conductive traces may be connected to the contacts. The dome may bear against a housing member. The button member may be movable with respect to the housing member from an unactuated position to an actuated position. The dome switch may form a footprint based upon the dome base area. The housing member may extend into a portion of the footprint and not into the remaining portion of the footprint allowing that space to be otherwise utilized.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a dome switch comprising first and second terminals and a collapsible dome that is movable between a relaxed state in which the first and second terminals are not electrically coupled and a collapsed state in which the dome electrically couples the first and second terminals; 
 a flex circuit comprising a flexible dielectric film and a plurality of conductive traces, wherein a first conductive trace of the plurality of conductive traces is electrically coupled to the first terminal; 
 a first spring contact member that is in physical contact with the first conductive trace, wherein the flex circuit comprises a first surface that faces the first and second terminals and a second surface to which the first spring contact member is attached; and 
 a circuit board comprising a first conductive pad, wherein the first spring contact member is positioned between the first conductive pad of the circuit board and the first conductive trace of the flex circuit in a compressed state. 
 
     
     
       2. The electronic device of  claim 1 , further comprising a button member that moves between an unactuated position and an actuated position, wherein the collapsible dome is movable between the relaxed state when the button member is placed in the unactuated position and the collapsed state when the button member is placed in the actuated position. 
     
     
       3. The electronic device of  claim 1 , wherein:
 a second conductive trace of the plurality of conductive traces is electrically coupled to the second terminal; 
 the electronic device further comprises a second spring contact member that is in physical contact with the second conductive trace; 
 the second surface of the flex circuit is attached to the second spring contact member; 
 the circuit board further comprises a second conductive pad; and 
 the second spring contact member is positioned between the second conductive pad of the circuit board and the second conductive trace of the flex circuit in a compressed state. 
 
     
     
       4. An electronic device comprising:
 a first housing member comprising a hole therethrough; 
 a button assembly comprising: 
 first and second electrical contacts; 
 a button member that moves within the hole between an unactuated position and an actuated position; and 
 a dome that is movable between a first state when the button member is in the unactuated position and a second state when the button member is in the actuated position, wherein the dome electrically couples the first and second electrical contacts when the dome is in the second state, and wherein the dome extends underneath a first area of the button member; and 
 a second housing member against which the dome presses when the button member is in the actuated position, wherein the second housing member extends underneath only a first portion of the first area of the button member. 
 
     
     
       5. The electronic device of  claim 4 , wherein only a first portion of the second housing member extends underneath the first portion of the first area of the button member. 
     
     
       6. The electronic device of  claim 5 , wherein a second portion of the second housing member does not extend underneath any portion of the first area of the button member. 
     
     
       7. The electronic device of  claim 4 , wherein the first area of the button member comprises the first and second electrical contacts. 
     
     
       8. The electronic device of  claim 4 , further comprising a display, wherein:
 the first housing member comprises a display cover glass layer; and 
 the display cover glass layer comprises:
 a first region through which the hole is formed; and 
 a second region that covers the display. 
 
 
     
     
       9. The electronic device of  claim 8 , wherein the hole comprises a sole menu button hole that is formed in the display cover glass layer. 
     
     
       10. The electronic device of  claim 8 , wherein:
 the button member comprises:
 an upper button member portion that is surrounded by the hole; and 
 a lower button member portion coupled to the upper button member portion; and 
 
 the lower button member portion extends beyond a cross-section of the hole. 
 
     
     
       11. The electronic device of  claim 10 , wherein:
 the lower button member portion moves away from the display cover glass layer without bending when the button member is moved to the actuated position; and 
 the lower button member portion contacts the display cover glass layer when the button member is moved to the unactuated position. 
 
     
     
       12. The electronic device of  claim 4 , wherein the button member comprises a rigid portion that extends beyond a cross-section of the hole. 
     
     
       13. An electronic device comprising:
 a first housing member comprising a hole therethrough; 
 a button assembly comprising:
 a button member that moves within the hole between an unactuated position and an actuated position; and 
 a dome switch comprising:
 first and second terminals; and 
 a dome that is movable between a first state when the button member is in the unactuated position and a second state in which the dome electrically couples the first and second terminals when the button member is in the actuated position, wherein the dome comprises an area defining a footprint for the dome switch; and 
 
 a second housing member comprising:
 a first portion formed from a first material; and 
 a second portion formed from a second material against which the button assembly presses when the button member is in the actuated position, wherein 
 
 the second housing member overlaps only part of the footprint. 
 
 
     
     
       14. The electronic device of  claim 13 , wherein the second portion is embedded within the first portion. 
     
     
       15. The electronic device of  claim 14 , wherein:
 the first material comprises plastic; and 
 the second material comprises a planar metal sheet. 
 
     
     
       16. The electronic device of  claim 14 , wherein the hole comprises a sole menu button hole that is formed in the display cover glass layer. 
     
     
       17. An electronic device comprising:
 a display that outputs visual information; 
 a display cover glass layer comprising: 
 a first region comprising a hole extending therethrough; and 
 a second region that covers the display; and
 a button assembly comprising:
 a button member that reciprocates vertically within the hole between an unactuated position and an actuated position; 
 first and second terminals; and 
 
 a dome that is movable between a first state when the button member is in the unactuated position and a second state in which the dome electrically couples the first and second terminals when the button member is in the actuated position. 
 
 
     
     
       18. The electronic device of  claim 17 , wherein:
 the button member comprises:
 a first portion that lies entirely within a cross-section of the hole; and 
 a second portion that extends beyond the cross-section of the hole; 
 
 the display cover glass layer comprises an inner surface; and 
 the second portion comprises a surface that bears against the inner surface of the display cover glass layer when the button member is in the unactuated position. 
 
     
     
       19. The electronic device of  claim 18 , wherein:
 the first portion comprises an outer surface that receives externally applied button actuation pressure from a user; and 
 the button actuation pressure moves the button member from the unactuated position to the actuated position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/029,928, filed Feb. 17, 2011, which is a continuation of U.S. patent application Ser. No. 12/113,910, filed May 1, 2008 (now U.S. Pat. No. 7,902,474), both of which are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     This invention relates generally to electronic devices, and more particularly, to button assemblies for portable electronic devices such as handheld electronic devices. 
     Handheld electronic devices and other portable electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. Popular portable electronic devices that are somewhat larger than traditional handheld electronic devices include laptop computers and tablet computers. 
     Portable devices are small in size, so space is at a premium. Conventional components, such as conventional buttons based upon dome switches may consume relatively large amounts of real estate. 
     It would therefore be desirable to be able to provide an electronic device such as a portable electronic device with an improved button assembly that consumes minimal real estate. 
     SUMMARY 
     A portable electronic device such as a handheld electronic device is provided. The portable electronic device may have buttons. An inverted dome switch assembly may be used to provide a button with electronic switching capabilities. The dome switch may have a small internal footprint. 
     The inverted dome switch assembly may have an inverted dome with a base and a conductive underside. The base may be attached to a movable button member having two electrical contacts facing the conductive underside and corresponding conductive traces to those contacts. A compression structure, connected to housing, may be coupled to the apex on the remaining side of the inverted dome. The movable button member may reciprocate from an unactuated position to an actuated position with respect to the housing and the compression structure. 
     In the actuated position, the inverted dome may be compressed or collapsed and the conductive underside may come into contact with the electrical contacts. The two electrical contacts may be electrically connected to each other through the conductive underside of the inverted dome. 
     In the unactuated position, the inverted dome is in a relaxed position and the electrical contacts are electrically disconnected from one another. The dome switch may form a footprint having the area of the base. The footprint may have a first portion and a second portion. The compression structure, supporting the compression point or contact point between the compression structure and the remaining side of the dome switch, may extend into the first portion. Other unrelated electrical components may extend into the second portion or, alternatively, the unused space may be otherwise utilized. 
     Further features of the invention, its 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 perspective view of an illustrative portable electronic device in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative portable electronic device in accordance with an embodiment of the present invention. 
         FIG. 3  is an exploded perspective view of an illustrative portable electronic device in accordance with an embodiment of the present invention. 
         FIG. 4  is a top plan view of a landing pad having concentric contact rings in a conventional button assembly. 
         FIG. 5  is a schematic view of a conventional button assembly prior to its being actuated. 
         FIG. 6  is a schematic view of a conventional button assembly illustrating the button assembly after it has been actuated. 
         FIG. 7  is a schematic view of a conventional button assembly illustrating the button assembly having a mis-hit during an actuation attempt. 
         FIG. 8  is a schematic view of a button assembly having an inverted metal dome shown in its unactuated state in accordance with an embodiment of the present invention. 
         FIG. 9  is a schematic view of a button assembly having an inverted plastic dome with an interior metal coating shown in its unactuated state in accordance with an embodiment of the present invention. 
         FIG. 10  is a schematic view of a button assembly having an inverted plastic dome with an interior metal coating shown in its actuated state in accordance with an embodiment of the present invention. 
         FIG. 11  is a bottom perspective view of button assembly having its housing member or compression structure not shown for clarity in accordance with an embodiment of the present invention. 
         FIG. 12  is a side cross-sectional side view of a button assembly shown in its unactuated state in accordance with an embodiment of the present invention. 
         FIG. 13  is a bottom perspective view of a button assembly having its housing member or compression structure shown in accordance with an embodiment of the present invention. 
         FIG. 14  is a top view of a button assembly illustrating a compression structure and additional components, each covering a portion of the dome button footprint, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates to dome switches. The dome switches may be used in button assemblies in electronic devices. 
     The electronic devices may be portable electronic devices such as laptop computers or small portable computers of the type that are sometimes referred to as ultraportables. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. 
     If desired, the electronic devices may be, for example, handheld wireless devices such as cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. The electronic devices may also be hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid portable electronic devices include a cellular telephone that includes media player functionality, a gaming device that includes a wireless communications capability, a cellular telephone that includes game and email functions, and a portable device that receives email, supports mobile telephone calls, has music player functionality and supports web browsing. These are merely illustrative examples. 
     An illustrative portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Device  10  of  FIG. 1  may be, for example, a handheld electronic device that supports 2G and/or 3G cellular telephone and data functions, global positioning system capabilities, and local wireless communications capabilities (e.g., IEEE 802.11 and Bluetooth®) and that supports handheld computing device functions such as internet browsing, email and calendar functions, games, music player functionality, etc. 
     Device  10  may have housing  12 . Antennas for handling wireless communications may be housed within housing  12  (as an example). 
     Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, housing  12  or portions of housing  12  may be formed from a dielectric or other low-conductivity material. Housing  12  or portions of housing  12  may also be formed from conductive materials such as metal. An advantage of forming housing  12  from a dielectric material such as plastic is that this may help to reduce the overall weight of device  10  and may avoid potential interference with wireless operations. 
     Housing  12  may have a bezel, such as bezel  14 . Bezel  14  may be formed from a conductive material and may serve to hold a display or other device with a planar surface in place on device  10  and/or to form an esthetically pleasing trim around the edge of device  10 . 
     Display  16  may be a liquid crystal display (LCD), an organic light emitting diode (OLED) display, or any other suitable display. The outermost surface of display  16  may be formed from one or more plastic or glass layers. If desired, touch screen functionality may be integrated into display  16  or may be provided using a separate touch pad device. An advantage of integrating a touch screen into display  16  to make display  16  touch sensitive is that this type of arrangement can save space and reduce visual clutter. 
     Display screen  16  (e.g., a touch screen) is merely one example of an input-output device that may be used with electronic device  10 . If desired, electronic device  10  may have other input-output devices. For example, electronic device  10  may have user input control devices such as button  19 , and input-output components such as port  20  and one or more input-output jacks (e.g., for audio and/or video). Button  19  may be, for example, a menu button. Port  20  may contain a 30-pin data connector (as an example). Buttons, for some devices, are designed for receipt of a human finger. As such, it may be desirable for the buttons to have a design and size to receive a human finger or thumb. Openings  22  and  24  may, if desired, form speaker and microphone ports. Speaker port  22  may be used when operating device  10  in speakerphone mode. Opening  23  may also form a speaker port. For example, speaker port  23  may serve as a telephone receiver that is placed adjacent to a user&#39;s ear during operation. In the example of  FIG. 1 , display screen  16  is shown as being mounted on the front face of handheld electronic device  10 , but display screen  16  may, if desired, be mounted on the rear face of handheld electronic device  10 , on a side of device  10 , on a flip-up portion of device  10  that is attached to a main body portion of device  10  by a hinge (for example), or using any other suitable mounting arrangement. 
     A user of electronic device  10  may supply input commands using user input interface devices such as button  19  and touch screen  16 . Suitable user input interface devices for electronic device  10  include buttons (e.g., alphanumeric keys, power on-off, power-on, power-off, and other specialized buttons, etc.), a touch pad, pointing stick, or other cursor control device, a microphone for supplying voice commands, or any other suitable interface for controlling device  10 . Although shown schematically as being formed on the top face of electronic device  10  in the example of  FIG. 1 , buttons such as button  19  and other user input interface devices may generally be formed on any suitable portion of electronic device  10 . For example, a button such as button  19  or other user interface control may be formed on the side of electronic device  10 . Buttons and other user interface controls can also be located on the top face, rear face, or other portion of device  10 . If desired, device  10  can be controlled remotely (e.g., using an infrared remote control, a radio-frequency remote control such as a Bluetooth® remote control, etc.). 
     Electronic device  10  may have ports such as port  20 . Port  20 , which may sometimes be referred to as a dock connector, 30-pin data port connector, input-output port, or bus connector, may be used as an input-output port (e.g., when connecting device  10  to a mating dock connected to a computer or other electronic device). Port  20  may contain pins for receiving data and power signals. Device  10  may also have audio and video jacks that allow device  10  to interface with external components. 
     Examples of locations in which antenna structures may be located in device  10  include region  18  and region  21 . These are merely illustrative examples. Any suitable portion of device  10  may be used to house antenna structures for device  10  if desired. 
     A schematic diagram of an embodiment of an illustrative portable electronic device such as a handheld electronic device is shown in  FIG. 2 . Portable device  10  may be a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a laptop computer, a tablet computer, an ultraportable computer, a hybrid device that includes the functionality of some or all of these devices, or any other suitable portable electronic device. 
     As shown in  FIG. 2 , device  10  may include storage  34 . Storage  34  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory), volatile memory (e.g., battery-based static or dynamic random-access-memory), etc. 
     Processing circuitry  36  may be used to control the operation of device  10 . Processing circuitry  36  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, processing circuitry  36  and storage  34  are used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. Processing circuitry  36  and storage  34  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using processing circuitry  36  and storage  34  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, protocols for handling 3 G communications services (e.g., using wide band code division multiple access techniques), 2G cellular telephone communications protocols, etc. To minimize power consumption, processing circuitry  36  may include power management circuitry to implement power management functions. 
     Input-output devices  38  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Display screen  16 , button  19 , microphone port  24 , speaker port  22 , and dock connector port  20  are examples of input-output devices  38 . 
     Input-output devices  38  can include user input-output devices  40  such as buttons, touch screens, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device  10  by supplying commands through user input devices  40 . Display and audio devices  42  may include liquid-crystal display (LCD) screens or other screens, light-emitting diodes (LEDs), and other components that present visual information and status data. Display and audio devices  42  may also include audio equipment such as speakers and other devices for creating sound. Display and audio devices  42  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications devices  44  may include communications circuitry such as radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, passive RF components, antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Device  10  can communicate with external devices such as accessories  46 , computing equipment  48 , and wireless network  49  as shown by paths  50  and  51 . Paths  50  may include wired and wireless paths. Path  51  may be a wireless path. Accessories  46  may include headphones (e.g., a wireless cellular headset or audio headphones) and audio-video equipment (e.g., wireless speakers, a game controller, or other equipment that receives and plays audio and video content), a peripheral such as a wireless printer or camera, etc. 
     Computing equipment  48  may be any suitable computer. With one suitable arrangement, computing equipment  48  is a computer that has an associated wireless access point (router) or an internal or external wireless card that establishes a wireless connection with device  10 . The computer may be a server (e.g., an internet server), a local area network computer with or without internet access, a user&#39;s own personal computer, a peer device (e.g., another portable electronic device  10 ), or any other suitable computing equipment. 
     Wireless network  49  may include any suitable network equipment, such as cellular telephone base stations, cellular towers, wireless data networks, computers associated with wireless networks, etc. 
     The antenna structures and wireless communications devices of device  10  may support communications over any suitable wireless communications bands. 
     To facilitate manufacturing operations, device  10  may be formed from two intermediate assemblies, representing upper and lower portions of device  10 . The upper or top portion of device  10  may sometimes be referred to as a tilt assembly. The lower or bottom may portion of device  10  may sometimes be referred to as a housing assembly. 
     The tilt and housing assemblies may each be formed from a number of smaller components. For example, the tilt assembly may be formed from components such as display  16  and an associated touch sensor. The housing assembly may include a plastic housing portion such as plastic housing portion  12  and printed circuit boards. Integrated circuits and other components may be mounted on the printed circuit boards. During manufacturing, one end of the tilt assembly may be inserted into the housing assembly. The tilt assembly may then be rotated (“tilted”) into place so that the upper surface of the tilt assembly lies flush with the upper edges of the housing assembly. 
     An exploded perspective view showing illustrative components of device  10  is shown in  FIG. 3 . 
     Tilt assembly  60  (shown in its unassembled state in  FIG. 3 ) may include components such as cover  62 , touch sensitive sensor  64 , display unit  66 , and frame  68 . Cover  62  may be formed of glass or other suitable transparent materials (e.g., plastic, combinations of one or more glasses and one or more plastics, etc.) and may have a button hole  21  for accessing a button  19  on frame  68 . Display unit  66  may be, for example, a color liquid crystal display. Frame  68  may be formed from one or more pieces. With one suitable arrangement, frame  68  may include metal pieces to which plastic parts are connected using an overmolding process. If desired, frame  68  may be formed entirely from plastic or entirely from metal. 
     Housing assembly  70  (shown in its unassembled state in  FIG. 3 ) may include a housing such as housing  12 . Housing  12  may be formed of plastic and/or other materials such a metal (metal alloys). For example, housing  12  may be formed of plastic to which metal members are mounted using fasteners and/or a plastic overmolding process. Bezel  14  may be formed of plastic or other dielectric materials or may be formed from metal or other conductive materials. Housing assembly  70  may also include one or more printed circuit boards such as printed circuit board  72 . Housing assembly  70  may also include components such as microphone  76  for microphone port  24 , speaker  78  for speaker port  22 , and dock connector  20 , integrated circuits, a camera, ear speaker for port  23 , audio jack, buttons, SIM card slot, etc. 
     A user of the device may provide input to the device by input devices such as button  19  or a touch screen. Button  19  is connected to frame  68  and may reciprocate within a button hole such as button hole  21  in cover  62 . When depressed by a user, button contacts within the button are connected to each other and the button completes a circuit. When this condition is detected, an intended function may be performed by the device. 
     Dome switches are sometimes used in handheld devices. A dome switch has a bubble or “dome” with a conductive underside. 
     The dome is typically positioned over a “landing pad” on a printed circuit board substrate.  FIG. 4  illustrates the landing pad on a printed circuit board of a conventional dome switch assembly. Printed circuit board  94  provides a landing pad area for the dome switch. Printed circuit board  94  has two traces: a first trace  96  that is connected to a dome switch contact such as fixed outer contact ring  92  and a second trace  98  that is connected to a second dome contact such as fixed center contact  90 . Printed circuit board  94  mechanically supports and electrically connects first trace  96  with fixed outer contact ring  92  and second trace  98  with inner contact  90  using conductive traces. 
     In contrast to traces  96  and  98 , which lie beneath or within the substrate of printed circuit board  94 , fixed center contact  90  and fixed outer contact ring  92  are formed on the top of printed circuit board  94  and are exposed so that corresponding conductive material within the dome may come into contact with them. In an electrical sense, fixed center contact  90  and fixed outer contact ring  92  form an open circuit such that, when they are electrically connected, they complete the circuit (i.e., the switch is closed). Fixed center contact  90  and fixed outer contact ring  92  are typically made of gold. 
     The “landing pad” or strike zone of the conductive dome positioned over printed circuit board  94  has a footprint. That is, the conductive zone must cover the footprint in order to actuate the switch. In a system of the type described in  FIG. 4 , the conductive dome must cover both the inner contact ring  90  and the outer contact ring  92 . As such, dome structures, in order to ensure contact and actuation, must cover the area of the circle defined by ring  92 . A conventional dome structure is generally larger than ring  92  to provide space for the dome to be properly attached to board  94 . 
       FIG. 5  is illustrative of a conventional dome switch in an unactuated or relaxed position. Conventional dome switch  100  has printed circuit board  94 , copper traces  96  and  98 , fixed center contact  90  and fixed outer contact ring  92  as discussed in connection with  FIG. 4 . Dome switch  100  further has a dome  101  made of polyethylene terephthalate (“PET”)  104  with underlying adhesive  103  that connects dome  101  to printed circuit board  94 . Dome  101  has an underside  105  coated with a conductive material such as graphite or gold. Around the perimeter of dome  101 , conductive underside  105  is electrically connected to fixed outer contact ring  92  in the dome relaxed state. Dome switch  100  further has an associated button  102  for actuating switch  100  by finger  108 . Button  102  may bear against dome  101  at contact structure  106 . 
       FIG. 6  is illustrative of dome switch  100  in an actuated or collapsed position. When button  102  is pushed downwardly as shown by arrow  110  by, for example, finger  108 , dome  101  is compressed and collapsed. Conductive underside  105  comes into contact with fixed center contact  90  such that fixed center contact  90  and fixed outer contact ring  92  form completed circuit  112  through conductive underside  105 , fixed center contact  90 , and fixed outer contact ring  92 , thereby closing the switch. 
     Conventional dome switch  100  consumes an area on printed circuit board  94  of at least πr 2 , where r is the radius of ring  92 . As such, area beneath the dome switch, which could be used otherwise to house electrical components such as resistors, capacitors, etc., is consumed by the landing pad for the dome switch. 
     Another drawback of the conventional dome switch is that there is a risk that there may be a mis-strike on the button  102  as shown in  FIG. 7 . The off-center mis-strike by finger  108  as shown by arrow  114  may cause conductive underside  105  to miss fixed center contact  90  so that a connection is not established. 
       FIG. 8  is a schematic view of a dome button assembly in accordance with an embodiment of the present invention. Dome button assembly  120  may have a bubble or “dome”  122 . Dome  122  may be in an inverted position with respect to a base member such as member  124  as compared to conventional dome switches. Dome  122  may be semispherical in shape having a base and an apex, or tip. The base of dome  122 , attached to member  124 , may be in the shape of a circle or any other suitable shape. Dome  122  may be made of a conductive material such as metal (e.g., gold) or any other suitable conductive, elastic material. The dome shape and material may provide the dome with elastic qualities so that, when compressed, it has the desired tactile response and does not surpass its yield point. 
     Dome  122  may be attached along its base or perimeter to member  124  by adhesive  126 . Member  124  may be formed from any suitable structures. For example, member  124  may be formed from flex circuit material (e.g., polyimide), a rigid circuit board material (e.g., epoxy), etc. Member  124  may be backed by plastic (e.g., a plastic button structure) to provide a mechanically sound structure that receives inverted dome  122  when it is compressed. Member  124  (with its optional rigid backing structures) may support and electrically connect dome button assembly components, i.e., an inner contact ring, an outer contact ring and the conductive material in inverted dome  122  using conductive pathways (traces) formed on the surfaces or interior of member  124 . Adhesive  126  may be formed of any suitable adhesive material such as two-sided pressure sensitive adhesive film (double sided tape), an adhesive without film backing, etc. 
     At its tip, or compression point, dome  122  may bear against a compression structure such as housing member  134 . A member  132  such as an epoxy member may be attached to dome  122  and may help define a robust contact surface for the dome switch. Member  134  may be a housing member such as a frame structure, a housing wall, a printed circuit board or any other member in device  10  that can provide a structurally sound compression zone for dome  122 . Positioned between housing member  134  and member  132  is shim  135 . Shim  135  may be made of a metal such as stainless steel or any other suitable material. Shim  135  provides a hardened base for the compression zone for dome  122 . Button member  124  may further have an inner contact such as inner contact pad or ring  130  and an outer contact such as outer contact ring  128 . Many times, inner contact pad  130  and outer contact ring  128  may be made of gold but other metals may be used if desired. Inner contact pad  130  and outer contact ring  128  are electrically connected to the conductive traces of member  124  as shown schematically by dashed lines  154  and  156 . 
     Dome button assembly  120  of the  FIG. 8  is shown in an unactuated state in which inner contact pad  130  is electrically disconnected from outer contact ring  128 . In the unactuated state, inner contact structure  130  and outer contact structure  128  form an open circuit in that the circuit having inner contact structure  130  and outer contact structure  128  lacks a complete path between a positive power source and ground. In the unactuated state, dome  122  is not collapsed. 
     Another illustrative embodiment of the dome button assembly is shown in  FIG. 9 . Dome button assembly  136  may have an inverted dome  138 . Inverted dome  138  may have an outer skin such as outer member  140  made of rubber, a plastic such as polyethylene terephthalate (“PET”) or any other suitable material. Inverted dome  138  may have an inner skin such as inner conductive member  142  (or underside) made of a conductive material. The conductive material may be gold or any other suitable conductive material and may be attached to the underside of outer member  140  with adhesive or any other suitable material. Alternatively, the conductive material may be applied by a coating process. 
     Dome  138  may be attached along its base to button member  124  by adhesive  126 . Dome button assembly  136  of  FIG. 9  is shown in an unactuated or relaxed state. 
     Dome button assembly  136  is shown in an actuated state in  FIG. 10 . As shown by direction arrow  144 , when sufficient pressure is applied to button member  124  to overcome upward pressure from inverted dome  138  as shown by arrow  143 , button member  124  moves in the direction of arrow  144 . Inverted dome  138  may have spring-like qualities and may act like a compression spring that produces upward pressure  143 . The movement of button member  124  in direction  144  applies pressure to inverted dome  138  along its base adjacent to button member  124  (or inverted landing pad) and at its tip (at member  132 ) at housing member  134  and shim  135 , thereby collapsing inverted dome  138 . When inverted dome  138  is in a collapsed state, inner conductive member  142  comes into contact with inner contact pad  130  and outer contact ring  128  on member  124 . This completes the circuit and turns the switch or button to an “ON” state. 
     The provision of the inverted dome and the inverted landing pad allows housing member  134 , which provides the compression point for the inverted dome, to be adjacent to only member  132 , at the tip of the inverted dome in order to actuate the switch and not to the remainder of the footprint of the dome. By contrast, a conventional dome switch requires that a printed circuit board having inner and outer contact points as well as corresponding traces be sufficiently large in area to cover the entire footprint of the dome, so that the area in the footprint is dedicated for this purpose and cannot be used otherwise. 
       FIG. 11  is a bottom perspective view of a button assembly in accordance with an embodiment of the present invention. Button assembly  136  is shown without member  134  for clarity. Dome button assembly  136  has inverted dome  138  attached to member  124  (shown through an air vent hole  148 ) using an adhesive or other suitable material. Inverted dome  138  may have an outer skin made of polyethylene terephthalate or any other suitable material and an inner skin made of a conductive material. Alternatively, the inverted dome may be made entirely of a conductive material such as a conductive metal (e.g., gold). Member  132  is shown attached to the tip of inverted dome  138 . Inverted dome  138  has an air vent hole  148  that allows air to escape the underside of inverted dome  138  when the inverted dome is changing from a relaxed state to a collapsed state. 
     Member  124 , which can be seen through air vent hole  148 , has inner contact pad  130  and outer contact ring  128 . The inner and outer contact pads may be concentric circles of conductive material such as copper or gold formed on the surface of member  124  facing the underside of inverted dome  138 . Member  124  may be attached to button member  150  by adhesive or other suitable material. 
     Lower button member  150  provides structural support for member  124 . Lower button member  150  receives button actuating energy transferred from external human finger contact, for example, and transfers this button actuating energy to member  124  which, in turn, uses this actuating energy to collapse inverted dome  138  to actuate dome button assembly  136 . Button member  150  may be formed from one or more layers of plastic (in the shape of button  19 ) and may reciprocate within a hole formed in cover glass  62  such as hole  21 , as shown in  FIG. 3 . 
     Member  124  may be formed from or connected to a flexible circuit such as flex circuit  152 . Flex circuit  152  may include conductive traces formed in or on a flexible dielectric film. The flexible dielectric film may be made of polyimide or other suitable materials having satisfactory thermal stability, chemical resistance, and mechanical properties. In the dome button assembly shown in  FIG. 11 , traces  154  and  156  are formed within the flexible dielectric film. Traces  154  and  156  run from terminals  168  and  166  to member  124 . Traces  154  and  156  continue on to inner contact ring  130  and outer contact ring  128  where holes may have been formed and contact pads may have been created so that the copper traces  154  and  156  may make electrical contact with outer contact ring  128  and inner contact pad  130 . 
     Stiffeners, such as stiffeners  158  and  164  may be bonded to flex circuit  152  with a pressure sensitive adhesive or a thermal set adhesive or other suitable materials. Stiffeners  158  and  164  may enhance the strength of the flex circuit so that flex circuit  152  can bend (e.g., in the region between stiffener  158  and dome  138  as the button is depressed). 
     Spring contacts  166  and  168  are electrically connected to traces  154  and  156  and provide electrical connectivity to the switch. A printed circuit board with mating contact pads or other suitable structures may be connected to terminals  166  and  168 . Spring contacts  166  and  168  may be made of beryllium copper or other suitable spring metals. If desired, the springs may be plated (e.g., with nickel). In  FIG. 11 , spring contacts  166  and  168  are shown in a relaxed state. 
       FIG. 12  is a cross-sectional side view of a button assembly shown in its unactuated or relaxed state. Dome button assembly  136  may have an inverted dome  138  with contact structure  132  that bears against shim  135  in housing member  134 . Spring contact  168  (shown in a compressed state), along with spring contact  166  (not shown), provide compression spring force and electrical conductivity between second flex circuit  152  and pads  169  on printed circuit board  170 . If desired, printed circuit board  170  may overlap a portion of the dome button footprint. 
     Dome button assembly  136  may have lower button member  150  (e.g., an opaque plastic member) attached to member  124 . Assembly  136  may also have transparent upper button member  172  that is positioned within button opening  174  in cover  62 . Cover  62  is typically made from glass but other suitable materials may be used. During operation, members  172  and  150  may reciprocate along axis  173  within hole  174 . Lower button member  150  may have an opening  176  for holding a white patterned button portion  178 . Portion  178  may form a white square when viewed from the front face of the device through transparent upper button member  172 . The white color of portion  178  is typically formed from white ink. Upper and lower button members  172  and  150  may be formed using a two-shot plastic molding process. As transparent upper button member  172  and lower button member  150  reciprocate vertically within button opening  174 , dome  138  is compressed and relaxed to operate the switch. 
     Housing member  134  may have a recess such as dome recess  180  that receives member  124  and dome  138  (when in a compressed state). Housing member  134  may also have a recess such as button recess  182  for receiving lower button member  150  when the button is depressed in direction  144 . 
       FIG. 13  is a bottom perspective view of a button assembly  136  and housing member  134 . Dome button assembly  136  has inverted dome  138  that bears against shim  135 . Flex circuit  152  connects the inner and outer contacts of the dome top and spring contacts  166  and  168 . As can be seen in the assembly of the type shown in  FIG. 13 , housing member  134  need not completely overlap the footprint of inverted dome  138 . As a result, the space left where member  134  (and associated member  137 ) does not overlap dome  138  may be used for other structures. 
       FIG. 14  is a top plan view of a button assembly illustrating how housing member  134  may only partly overlap dome  138 . Inverted dome  138  may have a compression point at member  132  that bears against overlapping housing member  134 . Flex circuit  152  connects spring contacts  166  and  168  to the inner and outer contacts of the switch. Housing member  134  may overlap the tip of dome  138  at member  132 , but need not extend over the remainder of the inverted dome footprint unless desired. As a result, internal area (as indicated by the dash-dot line  190 ) is available for use by other components, such as electrical components, printed circuit boards, flex circuits, wires, integrated circuits and other circuitry, cameras and other devices, etc. If desired, the saved space may be left unfilled to reduce the weight of device  10  and/or to provide room for parts to dissipate heat. 
     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: 20121231
Publication Date: 20140520
Grant Date: 20140520
Priority Date: 20080501
Inventors: MITTLEMAN ADAM DUCKWORTH
SCRITZKY ROBERT
HAMEL BRADLEY
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H13/79", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/79", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/23", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2215/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 41256386