PATENT DOCUMENT

Publication Number: US-9473609-B2
Application Number: US-201414550814-A
Country: US
Kind Code: B2

Title: Button integration for an electronic device

Abstract:
This application relates to various button related embodiments for use with a portable electronic device. In some embodiments, a snap clip can be integrated with a button bracket to save space where two separate brackets would take up too much space in the portable electronic device. In other embodiments, a tactile switch can be waterproofed by welding a polymeric layer atop a tactile switch assembly. In this way water can be prevented from contacting moisture sensitive components of the tactile switch assembly. The weld joining the polymeric layer to the tactile switch can include at least one gap to trapped gas surrounding the tactile switch assembly to enter and exit during heat excursions caused by various operating and/or assembly operations.

Claims:
What is claimed is: 
     
       1. A button assembly, comprising:
 a switch body; 
 a tactile switch coupled with a first surface of the switch body; 
 a polymeric film extending over and surrounding the tactile switch, wherein the polymeric film is joined to the switch body by a weld, the weld defining a plurality of gaps that allow air to pass into and out of an interior volume defined by the switch body and the polymeric film without allowing a liquid to enter the interior volume through a joint formed by the weld; and 
 a protective layer coupled to a second surface of the switch body, the second surface being positioned opposite the first surface, wherein the protective layer prevents ingress of the liquid into the switch body through a plurality of tooling pin holes defined by the second surface of the switch body. 
 
     
     
       2. The button assembly as recited in  claim 1 , wherein the plurality of gaps are covered by pressure sensitive adhesive subsequent to the button assembly being installed in an electronic device. 
     
     
       3. The button assembly as recited in  claim 1 , the plurality of gaps in the weld are defined by a series of troughs defined by the first surface of the switch body. 
     
     
       4. The button assembly as recited in  claim 1 , further comprising a plurality of welds that join the polymeric film to the switch body to form a channel through which surface tension prevents moisture intrusion into the interior volume. 
     
     
       5. The button assembly as recited in  claim 4 , wherein a portion of each of the plurality of welds run substantially parallel to one another to define the channel. 
     
     
       6. The button assembly as recited in  claim 5 , wherein the channel is no narrower than about 0.03 mm and wherein the channel extends for at least two millimeters. 
     
     
       7. The button assembly as recited in  claim 1 , wherein the plurality of gaps is closed by adhering the polymeric film to the switch body with pressure sensitive adhesive. 
     
     
       8. The button assembly as recited in  claim 1 , further comprising a plurality of welds that close the plurality of gaps after the button assembly is mounted within an electronic device. 
     
     
       9. The button assembly as recited in  claim 8 , wherein an angle formed by an intersection between the weld and each of the plurality of welds is greater than 90 degrees. 
     
     
       10. An electronic device, comprising:
 a housing; 
 a display assembly, comprising a substantially transparent display cover; and 
 a button assembly, comprising:
 a button cap positioned within an opening defined by the substantially transparent display cover and configured to receive a user input, 
 a switch body, 
 a tactile switch coupled with a first surface of the switch body and configured to receive the user input by way of the button cap, 
 a polymeric film coupled to the switch body and surrounding the tactile switch so that an interior volume is defined by the polymeric film and the switch body, wherein an interface between the polymeric film and the switch body prevents a liquid from entering the interior volume through the interface, and 
 a protective layer coupled to a second surface of the switch body, the second surface being positioned opposite the first surface, wherein the protective layer prevents ingress of the liquid into the switch body through a plurality of tooling pin holes defined by the second surface of the switch body. 
 
 
     
     
       11. The electronic device as recited in  claim 10 , wherein the protective layer is joined to the switch body by a weld. 
     
     
       12. The electronic device as recited in  claim 11 , wherein the weld joining the protective layer to the switch body defines a plurality of gaps that allow air to pass through the interface between the protective layer and the switch body. 
     
     
       13. A switch assembly for a portable electronic device, comprising:
 a switch body; 
 a dome switch coupled to a first surface of the switch body; 
 a membrane that is joined to the switch body via a weld, wherein a plurality of gaps that are formed in the weld define a plurality of vents having a size and shape to permit gas to be expelled from an interior volume defined by the switch body and the membrane while preventing a liquid from passing through the plurality of vents into the interior volume; and 
 a protective layer coupled to a second surface of the switch body. 
 
     
     
       14. The switch assembly of  claim 13 , wherein the second surface is positioned opposite the first surface, and wherein a plurality of tooling pin holes are included on the second surface. 
     
     
       15. The switch assembly of  claim 4 , wherein the plurality of tooling pin holes are positioned opposite the dome switch. 
     
     
       16. The switch assembly of  claim 14 , wherein the plurality of tooling pin holes are uniformly distributed throughout the second surface. 
     
     
       17. The switch assembly of  claim 14 , wherein the plurality of tooling pin holes are connected to the interior volume by a series of venting trenches. 
     
     
       18. The switch assembly of  claim 14 , wherein the protective layer is coupled to the switch body via a weld line that is free of gaps. 
     
     
       19. The switch assembly of  claim 13 , further comprising:
 an adhesive layer that is positioned between the switch body and the membrane.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International PCT Application No. PCT/US14/66754, with an international filing date of Nov. 21, 2014, and claims priority to U.S. Provisional Application No. 62/047,494, filed Sep. 8, 2014 and entitled “BUTTON INTEGRATION FOR AN ELECTRONIC DEVICE”, which is incorporated by reference herein in its entirety for all purposes. 
    
    
     FIELD 
     The described embodiments relate generally to user interface features. More particularly, the present embodiments relate to means for improving performance of and integrating user interface features into space constrained devices. 
     BACKGROUND 
     Recent advances in portable computing have allowed increasingly numerous numbers of components and sensors to be packed within a small form factor device housing. Accordingly, many components and/or functions may need to be combined and/or integrated together to accommodate increases in function that include additional parts and space within the device housing. In particular, fastening systems often need to be distributed around an interface between two components. When the joined components are joined around a periphery of the device, such fastening systems can compete for space with user interface elements distributed along the periphery of the device. Unfortunately, in some embodiments tight spacing of such components can prevent proper sealing of the device components and/or preclude placement of a user interface element in a convenient position. 
     SUMMARY 
     This paper describes various embodiments that relate to integration of button features on a portable electronic device. 
     A button assembly is disclosed. The button assembly includes at least the following components: a switch body; a tactile switch coupled with the switch body; and a polymeric film extending over and surrounding the tactile switch. The polymeric film is welded to the switch body by a weld that defines a number of gaps that allow air to pass into and out of an interior volume defined by the switch body and the polymeric film without allowing liquids to enter the interior volume through a joint formed by the weld. 
     An electronic device is disclosed. The electronic device includes at least the following: a housing; a display assembly, including a substantially transparent display cover; a button assembly. The button assembly includes at least the following: a button cap configured to receive a user input and positioned within an opening defined by the substantially transparent display cover; a switch body; a tactile switch coupled with a first surface of the switch body and configured to receive the user input by way of the button cap; and a polymeric film coupled to the switch body so that an interior volume is defined by the polymeric film and the switch body. An interface between the polymeric film and the switch body prevents liquids from entering the interior volume through the interface. 
     A button bracket for supporting button circuitry is disclosed. The button bracket includes at least the following elements: a rigid substrate defining a plurality of fastener openings; a tactile switch mounted to a first end of the rigid substrate; and a snap clip coupled with a second end of the rigid substrate. The rigid substrate is configured to be attached to a housing body by way of the fastener openings. The snap clip is configured to receive a rail extending from a protective cover that cooperates with the housing body to define an internal volume for an electronic device. 
     Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIGS. 1A-1B  show a perspective view and top view of an exemplary portable electronic device suitable for use with the described embodiments; 
         FIG. 2A  shows a perspective view of the portable electronic device depicted in  FIGS. 1A-1B  with a cover glass layer and display assembly removed to expose various joining components; 
         FIG. 2B  shows a top view of the portable electronic device depicted in the preceding figures to reveal how various retention mechanisms are distributed throughout a housing body of the portable electronic device; 
         FIG. 3A  shows a perspective view of a retention mechanism that includes a number of snap clips configured to receive a rail extending from a protective cover of the portable electronic device depicted in the preceding figures; 
         FIG. 3B  shows a perspective view of a button bracket combined with a snap clip that provides a backing for a button and a snap clip for receiving a rail connected to the protective cover of the portable electronic device; 
         FIG. 3C  shows a cross-sectional view of the button bracket depicted in  FIG. 4B  disposed within the housing body of the portable electronic device; 
         FIG. 4A  shows a cross-sectional view of a button assembly, which includes a tactile switch along the lines of a dome switch; 
         FIG. 4B  shows a top view of the button assembly depicted in  FIG. 4A ; 
         FIG. 4C  shows a top view of the button assembly depicted in  FIG. 4A  with a number of gaps interspersed along a weld line; 
         FIG. 4D  shows a side view of the button assembly depicted in  FIG. 4C ; 
         FIG. 4E  shows a top view of the button assembly depicted in  FIG. 4A  with a number of gaps in a weld line accounted for by layers of pressure sensitive adhesive; 
         FIG. 4F  shows a top view of the button assembly depicted in  FIG. 4A  with a number of gaps in a weld line closed by a second set of weld lines; 
         FIG. 4G  show a top view of a button assembly that includes two sets of welds that cooperate; 
         FIG. 5  depicts a flow diagram representing a method for mounting a button assembly; 
         FIGS. 6A-6B  show cross-sectional and bottom views of a button assembly including a protective layer that prevents ingress of liquid though a number of tooling pin holes defined by a switch body; 
         FIGS. 7A-7B  show cross-sectional and bottom views of a button assembly similar to the one depicted in  FIGS. 6A-6B  in which a number of venting trenches are defined by the switch body; 
         FIGS. 8A-8B  show cross-sectional and bottom views of a button assembly similar to the one depicted in  FIGS. 6A-6B  in which the protective layer is welded to the switch body; 
         FIGS. 9A-9B  show cross-sectional and bottom views of a button assembly similar to the one depicted in  FIGS. 8A-8B  in which the weld joining the protective layer to the switch body includes a number of breaks; and 
         FIGS. 10A-10B  show cross-sectional and bottom view of a button assembly similar to the one depicted in  FIGS. 8A-8B  in which a selected number of tooling pin holes are filled with epoxy. 
     
    
    
     DETAILED DESCRIPTION 
     Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
     The described embodiments relate primarily to features configured to integrate various user interface components along the lines of buttons into a portable electronic device. In some embodiments, a button bracket can be configured to include a retention mechanism that functions to connect two housing components together to form a device housing. The button bracket can be fastened to a first housing component by a number of fasteners. A first end of the button bracket can include features for supporting a tactile switch proximate to an interior surface of the first housing component that defines an opening for a button. When the button is actuated the button bracket provides a rigid substrate against which a tactile switch can be compressed by actuation of the button. Electrical contacts on the tactile switch can then relay a number of signals to a processor disposed within the device housing so that the processor can carry out actions consistent with actuation of the button. A second end of the button bracket can include a retention mechanism that includes a snap clip configured to grip a windowed opening defined by a portion of a second housing component. When the snap clip engages the windowed opening the first component can be secured with the second component. 
     A method for optimizing waterproofing of a tactile switch button of the portable electronic device is disclosed. A polymeric film can be welded over the tactile switch button to prevent liquids from contacting moisture sensitive portions of the tactile switch button. Unfortunately, when the polymeric film completely seals around the tactile switch button various assembly processes that generate heat can cause substantial expansion of gases trapped around the tactile switch button. This expansion can cause undesirable stretching of the polymeric film, which can adversely affect performance of the tactile switch. One solution to this problem is to interrupt the welding pattern so that small gaps can be left in the weld to permit the free exchange of air into and out of an area surrounding the tact switch button. In some embodiments, the gaps can be small enough so that surface tension of various liquids prevents the liquids from flowing into the tact switch button. In some embodiments, the gaps can be sealed after the tactile switch is installed in the portable electronic device. 
     These and other embodiments are discussed below with reference to  FIGS. 1A-10B ; however, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIGS. 1A-1B  show perspective views of electronic device  100  that is suitable for use with the described embodiments. Electronic device  100  includes display assembly  102 . Display assembly  102  can be utilized to present a touch based user interface to a user of electronic device  100 . In some embodiments, electronic device  100  also includes another user interface element along a top surface of electronic device  100  depicted as button  104 . Button  104  can be configured to perform specific functions depending on an operating state of electronic device  100 . In some embodiments, button  104  can be configured to return electronic device  100  to a higher-level menu and/or terminate use of a currently selected application. In other embodiments, a function of button  104  can be user configurable. Electronic device  100  can also include switch  106 . Switch  106  can serve many functions. In one embodiment switch  106  can extend through an opening defined by a sidewall of housing body  108  so that a user can alternate between different behaviors of electronic device  100 . For example, in some embodiments, switch  106  can allow electronic device  100  to change between an audible mode and a silent mode. Housing body  108  can be formed from a number of integrally formed sidewalls that cooperate with a bottom wall to define an interior volume or cavity in which many internal components can be positioned and protected. It should be noted that electronic device  100  can include many other buttons and or user interface elements not specifically discussed.  FIG. 1B  shows how a top surface of electronic device  100  can be covered by cover glass  110 . Cover glass  110  can define an opening  112  associated with an audio port configured to generate audio signals generated within electronic device  100  that exit electronic device  100  through opening  112 . In some embodiments, the audio signals can be along the lines of audio signals associated with telephone conversations. In other embodiments, media files can be played back through the audio port. Opening  112  can be covered by a layer or multiple layers of mesh that prevents most contaminates from entering into electronic device  100 , while allowing audio signals to pass through the layers of mesh substantially unhindered. Electronic device  100  can also include another user interface element along the lines of button  114 . Button  114  can be utilized in any number of ways including for powering on and off electronic device  100 . 
       FIG. 2A  shows a perspective view of electronic device  100  after removing cover glass  110 . As depicted, cover glass  110  includes rails  202  and  204  that extend into housing body  108  when cover glass  110  is joined to housing body  108 . Openings  206 , defined by rails  202  and  204 , allow rails  202  to be engaged by a number of snap clips included in retention mechanism  208  that is disposed within and coupled to housing body  108 . Housing body  108  can have an undercut geometry that allows the snap clips of retention mechanisms  208  to plastically deform into the undercut as openings  206  of rails  202  are engaged by retention mechanisms  208 . Rail  204  can define a single opening so that circuitry and components associated with button  114  can be accommodated.  FIG. 2B  shows a top view of housing body  108  with cover glass  110  removed from housing body  108 . While housing body  108  includes numerous internal components, most of the internal components have been excluded from this drawing to focus on components related to this disclosure.  FIG. 2B  shows a distribution of retention mechanisms  208  and notably button bracket  210 , which is configured to act both as a button bracket that supports components and switches associated with button  114  as well as including a snap clip configured to receive and engage with opening  206  of rail  204 . 
       FIGS. 3A and 3B  show perspective views of both retention mechanisms  208  and button bracket  210 .  FIG. 3A  depicts retention mechanism  208 , which can be mounted to an interior surface of housing body  108  (not shown) by way of fastener openings  302 . In some embodiments, retention mechanisms  208  are formed from metal substrate  301  and affixed to an interior surface of a sidewall that defines housing body  108 . Metal substrate  301  can be formed from any number of rigid metals, such as for example, steel and aluminum. Retention mechanism  208  includes two distinct snap clips  304 . In some embodiments snap clips  304  can be joined by a length of metal that includes z-retention feature  306 . Z-retention feature  306  can extend into a component arranged along an interior wall of housing body  108 . In this way z-retention feature can prevent movement of the component in at least a z-direction. 
       FIG. 3B  depicts button bracket  210  formed of metal substrate  301 , which also includes fastener openings  302 . In some embodiments, snap clip  304  of button bracket  210  can be welded to button bracket  210 , while in other embodiments, snap clip  304  can be integrally formed with button bracket  210 . In embodiments where snap clip  304  is welded to button bracket  210 , snap clip  304  can be formed by a stamping snap clip  304  from a sheet of steel. Button bracket  210  includes a thickened region  308  that is configured to meet a distal end of snap clip  304 . Thickened region  308  can be formed along one surface of metal substrate  301  as part of a forging process resulting in the formation of a solid protrusion taking the form of thickened region  308 . As depicted, a first end of snap clip  304  can be welded to button bracket  210 , while a second end of snap clip  304  can meet thickened region  308 . At least a portion of the circuitry associated with button  114  can be positioned within slot  310 . The circuitry can be fastened to button bracket  210  by engaging the circuitry with a fastener that passes through circuitry opening  312 . It should be noted that slots  314  arranged on either side of slot  310  can also be configured to accommodate various portions of the circuitry. In some embodiments, only a dome switch can be arranged on a side of button bracket  210  facing the opening in the wall through which button  114  extends. In other embodiments, supporting circuitry can also be secured to one side of button bracket  210 .  FIG. 3B  shows z-retention feature  306  positioned at one end of metal substrate  301 . In some embodiments, z-retention feature  306  can be formed by bending a central portion of metal substrate  301  away from a remaining portion of metal substrate  301 , as depicted. 
       FIG. 3C  depicts a cross-sectional view of snap clip  304  in accordance with section line A-A of  FIG. 3B  when it is installed in housing body  108  and engaged with rail  204 . As depicted, snap clip  304  interacts with thickened region  308  of button bracket  210  to enclose a lower portion of rail  204 . To remove rail  204  from snap clip  304  an upward force can cause snap clip  304  to plastically deform farther into undercut region  316  so that a resulting gap between snap clip  304  and thickened region  308  can allow the lower portion of rail  204  to be disengaged from within snap clip  304 . By disengaging these components, display assembly  102  and cover glass  110  can be removed from housing body  108 . This removal of rail  204  from snap clip  304  allows various internal components to be serviced and or replaced. 
       FIG. 4A  shows a cross-sectional view of button assembly  400 , which includes a tactile switch along the lines of a dome switch. Button assembly  400  utilizes a dome switch  402  to provide user feedback during actuation of button assembly  400 . Dome switch  402  includes a switch nub  404  positioned atop dome switch  402  to adjust a height at which dome switch contacts another internal component. This can allow for additional standoff between button assembly  400  and the other internal component. Cover film  406  can be positioned just above dome switch  402  and can prevent water from entering into and potentially causing damage to dome switch  402  by sealing cover film  406  to switch body  408  at locations surrounding dome switch  402 , thereby defining an interior volume within which dome switch  402  is contained. If water or moisture does contact dome switch  402 , the moisture can adversely affect dome switch  402  by causing shorts and/or corrosion of interior components. Cover film  406  can be sealed to switch body  408  by welding cover film  406  to switch body  408  at weld line  410 . In some embodiments, a laser welding apparatus can create weld line  410 . 
       FIG. 4A  also shows button assembly  400  mounted to substrate  414 . In some embodiments, substrate  414  can be a conventional printed circuit board while in other embodiments substrate  414  can be a flexible circuit board. In either case button assembly is electrically coupled with electrically conductive pathways disposed upon substrate  414  at exterior switch terminals  412 . It is the welding of exterior terminals  412  to substrate  414  that can cause and other assembly operations that can cause an increase in heat, which leads to the gas expansion problems described above. Other assembly operations can include the joining of button assembly  400  by an underfilling operation in which high temperature glue is applied to a surface of button assembly  400 . While exterior switch terminals are shown in exposed positions, it should be noted that other dampers and covers can be utilized to water-proof exterior switch terminals  412 . 
       FIG. 4B  shows a top view of button assembly  400  in which weld line  410  entirely surrounds dome switch  402  and seals air surrounding dome switch  402  beneath cover film  406 . In some embodiments, cover film  406  can be formed of a thin layer of polymeric film. In one particular embodiment, a polyethylene terephthalate polyester film can be used to form cover film  406 . Unfortunately, while entirely surrounding dome switch  402  with cover film  406  and completely sealing it to switch body  408  at weld line  410  can provide robust water intrusion prevention for button assembly  400 , subsequent welding or mounting operations can cause heat build up that causes at least temporary expansion of air or gases within dome switch  402 . This gas expansion can adversely affect a feel and/or function of dome switch  402  by causing permanent stretching of cover film  406 .  FIG. 4B  also depicts how internal switch terminals  412  enjoy the benefit of being encased beneath cover film  406 . Internal switch terminals can be electrical coupled with the external switch terminals  412  so that actuation of dome switch  402  can be transmitted to an external circuit disposed upon substrate  414 . 
       FIGS. 4C-4G  depict various solutions to the expanding gas problem discussed above.  FIG. 4C  depicts how weld line can include small breaks  416  that form vents in weld line  410  that allow air to exit from within the area defined by weld lines  410 . By sizing breaks  416  large enough to allow air to escape and small enough so that surface tension generally keeps liquid water from entering through breaks  416 , a robust water-proof barrier can exist without trapping air beneath cover film  406 . In some embodiments, breaks  416  can be sized to be about 0.05 mm long so that air exchange is allowed without significantly degrading the mechanical strength of the joint formed by weld lines  410 . By leaving breaks  416  between weld lines  410 , exposed air disposed within dome switch  402  doesn&#39;t stay trapped at any time and various heat excursions caused by high loading of an associated device will also not cause problems with expansion of air within button assembly  400 .  FIG. 4D  shows a cross-sectional side view of the solution depicted in  FIG. 4C  in accordance with section line B-B. In some embodiments, a trough or notch can be disposed within switch body  408  so that when a welding apparatus passes over the notch a small gap coincident with the notch is formed. In this way, break  416  can be generated without resetting the welding apparatus because the notch prevents cover film  406  from welding in the location directly over the notch. It should be noted that increasing the number of breaks  416  tends to decrease a risk of liquid intrusion. 
       FIG. 4E  shows another embodiment in which adhesive layers  418  are placed between switch body  408  and cover film  406  prior to forming weld lines  410 . In this way weld lines can partially overlap adhesive layers  418  and still leave a small break  416 . Because cover film  406  adheres to adhesive layers  418 , cover film  406  can be completely adhered to switch body  408 ; however, when pressure sensitive adhesive (PSA) that is compliant enough to allow air exchange during mounting and/or underfilling of the button assembly, then air within button assembly  400  can be exchanged without damaging button assembly  400 . Adhesive layers  418  can have a thickness of between about 10 and 20 microns. In this way a likelihood of water intruding within button assembly  400  through breaks  416  can be reduced. It should be noted that in some embodiments heat-cured or ultraviolet cured adhesive can be used and activated only after attaching button assembly  400  to a printed circuit board by underfilling or surface mounting (SMT) techniques. 
       FIG. 4F  shows another embodiment in which welds  420  are added after SMT and/or underfill of button assembly  400 . As depicted the welds should overlap to ensure the weld is fully completed even over the positioning tolerance of the welding system. The angle between the two welds should be as obtuse as possible, preferably greater than 135 degrees to prevent stress concentrations forming at the intersections of the welds during switch cycling. The welds can be positioned by using a vision system to determine a position of weld lines  410  so that overlap of welds  420  with weld lines  410  can be confirmed.  FIG. 4G  shows yet another embodiment in which long channel  422  is created between weld lines  410 . The long channel  422  prevents water from easily entering the switch but allows air to easily pass through it. In some embodiments, portions of weld lines  410  can be substantially parallel to form long channel  422 . This labyrinth-like design works best when the weld joints can overlap for multiple millimeters with a very small gap of greater than 0.3 mm in between the two welded paths. 
       FIG. 5  shows a flow diagram representing a method for electrically and mechanically coupling a button assembly to a substrate including at least one external circuit. At a first step  502 , a thin polymeric film is welded over a switch body to protect a tactile switch disposed on the switch body. At step  504 , the switch body is surface mounted (SMT) to a printed circuit board (PCB). During the SMT processes air is allowed to escape from within a volume defined by the thin polymeric film and the switch body through a number of gaps left open during the welding process. At step  506 , the joint between the PCB and the switch body can be enhanced by underfilling it with heated adhesive. In some embodiments, after the SMT process and the underfilling at step  508 , the gaps can be closed off using any of a number of processes. The processes can include adding additional welds to close the gaps between the welds, using an adhesive substrate to create a weak bond over the gap, and/or positioning the welds to create a long channel between the welds. 
       FIG. 6A  shows a cross-sectional view of button assembly  600 , which includes a tactile switch along the lines of a dome switch having a configuration similar to the dome switch depicted in  FIG. 4A . However, while the embodiment described in  FIGS. 4A and 4B  led to a condition in which gas expansion caused damage to cover film  406  and/or dome switch  402  due to cover film  406  completely sealing gases around dome switch  402 , in this embodiment, body  408  includes tooling pin holes  602  that can facilitate the transfer of air into and out of the interior volume defined by cover film  406  and switch body  408 . Unfortunately, tooling pin holes  602  can allow water to ingress into the interior volume of button assembly  600 . Consequently, protective layer  604  can be added along a bottom surface of switch body  408  to prevent water or liquid ingress. Protective layer  604  can be a thin layer of pressure sensitive adhesive (PSA) or heat activated film (HAF). Tooling pin holes  602  can provide an additional avenue through which air can pass into or out of switch body  408 . In some embodiments, this air exchange could be facilitated both through tooling pin holes  602  and through breaks or gaps in weld lines  410  that secure cover film  406  to switch body  408  (e.g., see  FIG. 4C ).  FIG. 6B  shows a bottom view of button assembly  600 , and how tooling pin holes  602  can be evenly spread across a bottom surface of switch body  408 .  FIG. 6B  also shows how protective layer  604  extends across all of tooling pin holes  602 , so that liquid in proximity to tooling pin holes  602  is prevented from entering the interior volume of button assembly  600 . 
       FIG. 7A  shows another button assembly  700  similar to the one shown in  FIG. 6A  in which a series of venting trenches  702  are from along a bottom surface of switch body  408 . Button assembly  700  includes venting trenches  702  that provide a pathway along which air can flow. Such a configuration can prevent undue bubbling of protective layer  604  when air within the interior volume defined by button assembly  700  expands or contracts causing air within the interior volume to exit or enter button assembly  700 . To prevent the ingress of liquids, entry area  704  and in some embodiments venting trenches  702  can be narrow enough so that the surface tension of liquids prevents the liquid from entering button assembly  700 .  FIG. 7B  shows a bottom view of button assembly  700  in which venting trenches  702  are laid out in an exemplary manner. This configuration allows air to flow directly from either of two opposing sides of protective layer  604  into any one of tooling pin holes  602 . It should be understood that this layout of venting trenches  702  is made for exemplary purposes only. For example, venting trenches  702  can be arranged so that only a subset of tooling pin holes  602  is accessible by venting trenches  702 . 
       FIG. 8A  shows another configuration in which protective layer  604  is welded over the bottom surface of switch body  408  at weld lines  410 . In such an embodiment, protective layer  604  need not have any inherent adhesive properties and can be formed from a more neutral material along the lines of a polyester film. By positioning protective layer  604  in this way, protective layer  604  can block both air exchange and liquid ingress through tooling pin holes  602 . In some embodiments, this can be desirable when air exchange pathways are already setup through cover film  406 , as shown in previously described embodiments.  FIG. 8B  shows how weld line  410  can create an unbroken perimeter around protective layer  604 , thereby preventing air that passes through tooling pin holes  602  from escaping through an interface between protective layer  604  and switch body  408 . 
       FIGS. 9A-9B  show another configuration in which protective layer  604  is welded to switch body  408 ; however, in this embodiment weld  410  associated with protective layer  604  includes a number of breaks that allow air to pass through the interface between switch body  408  and protective layer  604 . In some embodiments, as depicted, weld  410  can be arranged so that each one of tool pin holes  602  is isolated from other tool pin holes  602  by weld lines  410 . Some weld lines  410  can completely isolate tool pin holes  602 , thereby preventing gases from escaping the isolated tool pin holes  602 . Other weld lines  410  can allow air exchange through a single tooling pin hole  602  by way of one or more gaps or breaks  416  in weld line  410 . 
       FIGS. 10A-10B  show another embodiment in which selected ones of tool pin openings  602  are filled with epoxy  1002 . In this way, the number of tooling pin holes  602  that are exposed can be limited so that a rate at which air cycles into and out of button assembly  1000  can be established independent of a number of tooling pin holes  602  necessary for a particular assembly or machining operation. Weld line  410  can include a number of breaks  416  that allow air to cycle into and out of tool pin holes  602  that are not filled with epoxy  1002 . In some embodiments, epoxy can be utilized to limit a size of one or all of tooling pin holes  602 . While about half of tooling pin holes  602  are filled with epoxy  1002  any number of tooling pin holes  602  can be filled. For example, tooling pin holes  602  can be arranged near a periphery of protective layer  604  while centrally disposed tool pin holes  602  can be left open. It should be noted that any of the previously discussed embodiments could be combined or mixed to achieve a balanced flow of air into and out of the interior volume defined by a button assembly. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a processor of a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20141121
Publication Date: 20161018
Grant Date: 20161018
Priority Date: 20140908
Inventors: SHUKLA ASHUTOSH Y.
CATER TYLER B.
COHEN SAWYER I.
HUO EDWARD S.
PAKULA DAVID A.
BUSTLE BENJAMIN SHANE
SHAH DHAVAL N.
ZHANG YAOCHENG
KATIYAR VIVEK
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/0249", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2213/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/236", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2213/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B2001/3894", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2213/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2207/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2207/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/3888", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/236", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2207/032", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2213/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/016", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2213/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/236", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2213/016", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 55438136