PATENT DOCUMENT

Publication Number: US-10831299-B1
Application Number: US-201715792601-A
Country: US
Kind Code: B1

Title: Force-sensing button for electronic devices

Abstract:
An input device for an electronic device includes one or more pressure sensors for detecting inputs. In one embodiment, a pressure sensor is operably coupled to a compression chamber and configured to detect changes in pressure in the compression chamber. The changes in pressure in the compression chamber may be registered as inputs by the electronic device. The pressure sensor may be located next to, instead of below, the input member, and therefore, the thickness of the button assembly can be reduced compared to conventional designs.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a device housing; 
 a display coupled to the device housing and configured to display a graphical output; and 
 a button assembly at least partially disposed in the device housing, the button assembly comprising:
 an input member configured to move in response to receiving an input; 
 a compression chamber defining a sealed volume that is sealed from an external environment; and 
 a pressure sensor operably coupled to the compression chamber and configured to detect a pressure within the compression chamber; wherein: 
 movement of the input member changes a volume of the compression chamber, thereby changing the pressure within the compression chamber; 
 the pressure sensor is configured to output a signal in response to the pressure changing within the compression chamber; and 
 the signal causes the graphical output of the display to change. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein:
 the button assembly further comprises a shaft operably coupled to the input member and extending into the compression chamber; and 
 the shaft is configured to move in response to the input member moving, thereby changing the volume of the compression chamber. 
 
     
     
       3. The electronic device of  claim 1 , wherein the input member is configured to at least one of rotate or translate. 
     
     
       4. The electronic device of  claim 1 , wherein:
 the electronic device is an electronic watch; and 
 the input member is configured to rotate and translate. 
 
     
     
       5. The electronic device of  claim 1 , wherein the button assembly further comprises:
 a reference chamber; and 
 the pressure sensor is configured to determine a differential pressure between the compression chamber and the reference chamber. 
 
     
     
       6. The electronic device of  claim 1 , wherein the button assembly further comprises a pressure change actuator configured to change the pressure within the compression chamber, thereby providing tactile output through the input member. 
     
     
       7. The electronic device of  claim 1 , wherein the button assembly further comprises a valve configured to couple the compression chamber with a reference chamber, the valve further configured to equalize the pressure in the compression chamber with a pressure in the reference chamber. 
     
     
       8. The electronic device of  claim 1 , wherein the button assembly further comprises a seal configured to provide an airtight seal of the compression chamber. 
     
     
       9. The electronic device of  claim 1 , wherein the button assembly comprises a touch sensor. 
     
     
       10. An electronic device comprising:
 a device housing; 
 a display coupled to the device housing; 
 a button housing at least partially disposed in the device housing and defining an opening; 
 an input member; 
 a shaft coupled to the input member and extending through the opening; 
 a seal positioned in the opening and compressed between the shaft and a surface of the button housing; 
 a compression chamber coupled to the opening and having a sealed volume configured to contain a fluid; and 
 a pressure sensor coupled to the compression chamber and configured to detect a change in a pressure within the compression chamber in response to movement of the shaft. 
 
     
     
       11. The electronic device of  claim 10 , wherein:
 the shaft has a generally cylindrical shape; 
 the seal is an o-ring seal disposed around the shaft; 
 the shaft comprises a collar configured to retain the shaft in the opening; 
 the button housing comprises a flange for attaching the button housing to the device housing of the electronic device; and 
 the electronic device further comprises an electrical connector configured to couple the pressure sensor to a processor of the electronic device. 
 
     
     
       12. The electronic device of  claim 10 , wherein:
 the electronic device further comprises a reference chamber coupled to the pressure sensor; and 
 the pressure sensor is a differential pressure sensor configured to detect a difference between the pressure within the compression chamber and a pressure within the reference chamber. 
 
     
     
       13. The electronic device of  claim 10 , wherein the compression chamber is positioned in at least one of the input member, the button housing, or the device housing of the electronic device. 
     
     
       14. The electronic device of  claim 10 , wherein:
 the button housing is attached to the device housing of the electronic device; and 
 the button housing and the device housing cooperatively define at least a part of the compression chamber. 
 
     
     
       15. The electronic device of  claim 10 , wherein:
 the shaft is a first shaft and coupled to the input member near a first end; 
 the compression chamber is a first compression chamber; 
 the pressure is a first pressure; 
 the pressure sensor is a first pressure sensor; and 
 the electronic device further comprises:
 a second shaft coupled to the input member near a second end; 
 a second compression chamber having a second volume that changes based on a position of the second shaft; and 
 a second pressure sensor coupled to the second compression chamber and configured to detect a change in a second pressure within the second compression chamber in response to movement of the second shaft. 
 
 
     
     
       16. The electronic device of  claim 10 , further comprising a flexible membrane positioned below the shaft. 
     
     
       17. The electronic device of  claim 10 , wherein the shaft is threaded. 
     
     
       18. A method for detecting an input at a button of an electronic device, the method comprising:
 detecting, using a pressure sensor, a pressure change of a material contained within a sealed volume of a compression chamber due to movement of the button; 
 determining that a magnitude of the pressure change exceeds a first threshold; 
 in response to determining that the magnitude of the pressure change exceeds the first threshold, determining whether a rate of the pressure change exceeds a second threshold; and 
 in response to determining that the rate of the pressure change exceeds the second threshold, registering an input at the electronic device. 
 
     
     
       19. The method of  claim 18 , wherein detecting the pressure change comprises comparing a pressure within the compression chamber to a pressure within a reference chamber of the button. 
     
     
       20. The method of  claim 18 , wherein a graphical output of a display of the electronic device changes in response to registering the input.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a non-provisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 62/546,387, filed Aug. 16, 2017 and titled “Force-Sensing Button for Electronic Devices,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     Embodiments described herein relate to electronic devices, and in particular, to electronic devices that incorporate a button that includes a pressure sensor for detecting inputs. 
     BACKGROUND 
     Many traditional electronic devices include buttons, keys, or other similar input mechanisms. Many traditional buttons require a switch or sensor to be placed directly below an input surface, often on an axis of movement of the button. This increases the size of the button, and may increase the size of the electronic device that includes the button. In many cases, it is advantageous to minimize the size of the button and the electronic device that includes the button. The embodiments described herein are directed to electronic devices having a button or input device that may address these and other issues that are associated with some traditional input mechanisms. 
     SUMMARY 
     Certain embodiments described herein relate to, include, or take the form of an electronic device that includes a device housing, a display, and a button assembly. The display is coupled to the device housing and configured to display a graphical output. The button assembly is at least partially disposed in the device housing. The button assembly includes an input member configured to move in response to receiving an input. The button assembly further includes a compression chamber and a pressure sensor operably coupled to the compression chamber. Movement of the input member changes the volume of the compression chamber, thereby changing a pressure in the compression chamber. The pressure sensor is configured to output a signal in response to the pressure changing in the compression chamber. The signal causes the graphical output of the display to change. 
     Other embodiments described generally reference a button assembly that includes a button housing defining an opening, an input member, and a shaft coupled to the input member and extending through the opening. The button assembly further includes a seal positioned in the opening and compressed between the shaft and a surface of the button housing. The button assembly further includes a compression chamber coupled to the opening and having a volume. The button assembly further includes a pressure sensor coupled to the compression chamber and configured to detect a change in a pressure of the compression chamber in response to movement of the shaft. 
     Still further embodiments described herein generally reference a method for detecting an input at a button of an electronic device. The method includes the steps of detecting a pressure change in a compression chamber of the button and determining that a magnitude of the pressure change exceeds a first determined threshold. The method further includes determining, in response to determining that the magnitude of the pressure change exceeds the first determined threshold, whether a rate of the pressure change exceeds a second determined threshold. The method further includes registering, in response to determining that the rate of the pressure change exceeds the second determined threshold, an input at the electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to representative embodiments illustrated in the accompanying figures. It should be understood that the following descriptions are not intended to limit this disclosure to one preferred embodiment. To the contrary, the disclosure provided herein is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments, and as defined by the appended claims. 
         FIG. 1A  illustrates an example electronic device that may incorporate a button assembly according to one or more embodiments presented herein. 
         FIG. 1B  is a cross-section of the button assembly of the electronic device taken through section line A-A of  FIG. 1A . 
         FIG. 2A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 2B  illustrates the cross-section of  FIG. 2A  with the input member in a depressed position. 
         FIG. 2C  illustrates the cross-section of  FIGS. 2A-2B  with the input member in an extended position. 
         FIG. 2D  is a cross section of an example button assembly taken through section line B-B of  FIG. 2A . 
         FIG. 3A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 3B  illustrates a removed view of a portion of the example button assembly identified by the enclosed circle  1 - 1  shown in  FIG. 3A . 
         FIG. 4  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 5  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 6A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 6B  illustrates the input member and the shaft translated downward. 
         FIG. 7  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. 
         FIG. 8  illustrates an example wearable electronic device that may incorporate one or more button assemblies as described herein. 
         FIG. 9A  is a cross-section of a watch crown disposed in an opening of the wearable electronic device taken through section line C-C of  FIG. 8 . 
         FIG. 9B  is a cross-section of the watch crown taken through section line D-D of  FIG. 9A . 
         FIG. 9C  illustrates the cross-section of  FIG. 9B  with the arm displaced in response to a torque applied in the clockwise direction. 
         FIG. 9D  illustrates the cross-section of  FIG. 9B  with the arm displaced in response to a torque applied in the counter-clockwise direction. 
         FIG. 10  is a cross-section of a watch crown disposed in an opening of a wearable electronic device according to an embodiment. 
         FIG. 11  is a cross-section of an example button assembly, according to an embodiment. 
         FIG. 12  is a cross-section of an example button assembly, according to an embodiment. 
         FIG. 13  is a simplified flow chart depicting example operations of a processor of an electronic device with a button assembly as described herein. 
     
    
    
     The use of the same or similar reference numerals in different figures indicates similar, related, or identical items. 
     Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the claims. 
     The embodiments disclosed herein are directed to an input device for use as part of, or with, an electronic device. An electronic device receives inputs from users manipulating the input device. The input device may include one or more pressure sensors for detecting forces applied to the input device; such forces may be interpreted as inputs by the associated electronic device. In various embodiments, the pressure sensors detect inputs by measuring a pressure change in a compression chamber. The force-sensing input device may be configured to control or otherwise provide inputs to the electronic device. In various embodiments, the force-sensing input device may be used to control a visual or graphical output of a display of the electronic device. A force-sensing input device may be configured, for example, as a power button, a key of a keyboard, a control button (e.g., volume control), a home button, a watch crown, a joystick, a trackpad, and so on. 
     Some forms of input devices use a switch or other type of sensor positioned below the device, for example along an axis of movement of a button to generate an input. This may increase the size (e.g., thickness) of the input device, thereby occupying more space within an electronic device housing. In some embodiments, the electronic device housing must be enlarged (e.g., made thicker) to accommodate such input devices. 
     By contrast, some button assemblies described herein include one or more pressure sensors configured to detect inputs at an input member. In various embodiments, a pressure sensor detects pressure changes in one or more compression chambers. The pressure changes may be interpreted by the electronic device as a force applied to the input device (e.g., an input to the electronic device). The compression chamber is a sealed volume configured to contain compressible contents such as air, other gases, liquids, and so on. The compression chamber has a volume that changes based on movement of an input member. When the compression chamber is sealed, a change in volume results in a change in pressure according to Boyle&#39;s law, which states that the pressure in a container containing a gas increases as the volume of the container decreases. For example, as the volume of the compression chamber decreases, the pressure in the compression chamber increases. Conversely, as the volume of the compression chamber increases, the pressure in the compression chamber decreases. 
     A pressure sensor is operably and physically coupled to the compression chamber and configured to detect changes in pressure in the compression chamber. Accordingly, when a user exerts a force (e.g., presses, pulls, and so on) on the input member, the pressure in the compression chamber changes, and the pressure sensor detects a change in pressure that may be interpreted as an input by the electronic device. 
     The pressure sensor may be located next to, instead of along an axis of motion of, the input member. Many conventional button sensors require that the sensor be placed below the input member, for example in a stack. The button assemblies described herein do not require such an arrangement, and therefore, the thickness of the button assembly can be reduced compared to conventional designs. 
     Pressure changes and/or pressure values detected by the pressure sensor may be used to detect inputs, or may be correlated to inputs, received at the button assembly. In one embodiment, if the magnitude of a pressure change exceeds or goes below a threshold, an input may be registered, for example by a processor of the electronic device. In another embodiment, if the absolute or differential pressure value is above or below a threshold, an input may be registered. In still other embodiments, a magnitude of a pressure change or pressure value may indicate whether an input occurs and/or a degree of measure of the input (e.g., a measure of a force applied to the input surface). In another embodiment, a range of inputs corresponds to a range of forces. In various embodiments, additional criteria, such as the timing and/or rates of pressure changes, may be used to register inputs. 
     In various embodiments, button assemblies may include multiple compression chambers and/or multiple pressure sensors. These may be used to determine additional information about an input, such as a location of an input on the input member, a tilt of an input member, a directional indication, and so on. 
     Additionally, button assemblies may include one or more reference chambers and/or reference pressure sensors to determine a differential pressure. A reference chamber is a sealed volume, which does not change volume in response to a force being applied at the input member. As such, it may be used as a basis of comparison to determine the pressure change in the compression chamber that is a result of the force being applied. The pressure in the reference chamber may change based on environmental factors, such as atmospheric pressure changes, temperature changes, and the like. As a result, a change in the pressure of the compression chamber relative to the pressure in the reference chamber is more likely to be a result of a force being applied to the input member than a change in the pressure of the compression chamber relative to atmospheric pressure. This may lead to more effective input detection. 
     The button assemblies described herein may include one or more valves configured to fluidly couple a compression chamber with one or more volumes (e.g., reference chambers, enclosed volumes, and/or the atmosphere). In various embodiments, valves may be used to equalize pressure between multiple chambers, between a chamber and the atmosphere, and so on. In another embodiment, the button assembly includes a pressure change actuator for changing the pressure in the compression chamber to provide a tactile output (e.g., feedback) through the input surface. 
     Detailed embodiments of these general considerations will now be disclosed in relation to the accompanying figures. 
       FIG. 1A  illustrates an example electronic device  100  that may incorporate a button assembly  102 , according to one or more embodiments presented herein. The electronic device  100  includes a device housing  104  and a button assembly  102  disposed in an opening of the device housing. The button assembly  102  includes an input surface on which inputs can be received. The electronic device  100  may additionally include a display  111  and one or more buttons  112 . 
     The button assembly  102  may be disposed at any of several locations on (or in) the device housing  104 . For example, the button assembly  102  may be positioned along a surface of the device housing  104  as depicted in  FIG. 1A . Alternatively or additionally, the button assembly  102  may be positioned on a different surface or portion of an electronic device  100 , such as a sidewall, a top surface, a bottom surface, and the like. 
     The button assembly  102  may be shaped in any of several geometries. For example, the button assembly  102  may be circular, oblong, or rectangular. In embodiments in which the button assembly  102  extends from the electronic device  100 , the button assembly  102  may present a first geometry for a portion extending from the electronic device, and a second geometry for another portion contained within the device housing  104 . 
     The electronic device  100  can also include one or more internal components (not shown) typical of a computing or electronic device, such as, for example, one or more processors, memory components, network interfaces, and so on. Furthermore, although the electronic device  100  is illustrated as a cellular phone, It should be appreciated that any number of electronic devices may incorporate a button assembly, including (but not limited to): a computer, a laptop computer, a tablet computer, a phone, a wearable device, a health monitoring device, a home or building automation device, a home or building appliance, a craft or vehicle entertainment, control, and/or information system, a navigation device, a personal digital assistant, a media player, a watch, another wearable device, a touch-sensitive device, a keypad, a keyboard, and so on. 
     The device housing  104  provides a device structure, defines an internal volume of the electronic device  100 , and houses device components. In various embodiments, the device housing  104  may be constructed from any suitable material, including metals (e.g., aluminum, titanium, and the like), polymers, ceramics (e.g., glass, sapphire), and the like. In one embodiment, the device housing  104  is constructed from multiple materials. The device housing  104  can form an outer surface or partial outer surface and protective case for the internal components of the electronic device  100 . 
     The display  111  can be implemented with any suitable technology, including, but not limited to liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. The display  111  provides a graphical output, for example associated with an operating system, user interface, and/or applications of the electronic device  100 . In one embodiment, the display  111  includes one or more sensors and is configured as a touch-sensitive (e.g., single-touch, multi-touch) and/or force-sensitive display to receive inputs from a user. In various embodiments, a graphical output of the display  111  is responsive to inputs provided to the button assembly. 
       FIG. 1B  is a cross-section of the button assembly of the electronic device  100 , taken through section line A-A of  FIG. 1A . The button assembly  102  includes a button housing  120 , an input member  110 , a compression chamber  130 , and a pressure sensor  140 . The input member  110  is configured to receive inputs and translate, deflect, bend, or otherwise move or be displaced, relative to the button housing  120 . The movement of the input member  110  changes a volume of the compression chamber  130 . The compression chamber  130  is sealed such that, as the volume of the compression chamber  130  changes, the pressure in the contents of the compression chamber changes according to Boyle&#39;s law. The pressure sensor  140  is operably coupled to the compression chamber  130  and configured to detect changes in pressure in the compression chamber. Accordingly, when a user exerts a force (e.g., presses, pulls, and so on) on the input member  110 , the pressure sensor  140  detects a change in pressure that may be interpreted as an input by the electronic device  100 . 
     The compression chamber  130  is a sealed void configured to contain contents such as air, other gases, liquids, and so on. The compression chamber  130  has a volume that changes based on movement of the input member  110 . As described above, when the compression chamber  130  is sealed, a change in volume results in a change in pressure. For example, as the volume of the compression chamber  130  decreases, the pressure in the compression chamber increases. Conversely, as the volume of the compression chamber  130  increases, the pressure in the compression chamber decreases. 
     In one embodiment, the compression chamber  130  is formed in the button housing  120  and/or the input member  110 . In another embodiment, the compression chamber  130  is formed by one or more components of the electronic device  100  and/or the button assembly  102 . For example, the compression chamber  130  may be formed between one or more surfaces of the button housing  120  and other components of the electronic device  100 , such as a surface of the device housing  104 , as described in more detail below with respect to  FIGS. 11 and 12 . 
     The pressure sensor  140  is operably and physically coupled to the compression chamber  130  and configured to output a signal in response to the pressure changing in the compression chamber  130 . The signal that indicates a pressure change may be interpreted by the electronic device as an input (e.g., a force applied to the input member). The pressure sensor may be configured to measure pressure changes, absolute pressure and/or differential pressure. In various embodiments, the pressure sensor  140  may measure pressure and/or pressure changes using a variety of methods and techniques, including piezoresistive sensing, capacitive sensing, electromagnetic sensing, piezoelectric sensing, optical sensing, potentiometric sensing, and so on. In various embodiments, different pressure sensor outputs may correspond to different inputs. For example, an amount of a pressure change may correspond to a degree of measure of the input force (e.g., force detection). Similarly, different directions of pressure changes (e.g., pressure increases and pressure decreases) may correspond to different inputs. 
     As noted above, pressure changes and/or pressure values detected by the pressure sensor  140  may be used to detect inputs received at the button assembly  102 . In one embodiment, if the magnitude of a pressure change exceeds or goes below a threshold, an input may be registered, for example by a processor of the electronic device  100 . In another embodiment, if the absolute or differential pressure value is above or below a threshold, an input may be registered. In still other embodiments, a magnitude of a pressure change or pressure value may indicate whether an input occurs and/or a degree of measure of the input (e.g., a measure of a force applied to the input surface). In various embodiments, additional criteria, such as the timing and/or rates of pressure changes may be used to register inputs. This is discussed in more detail below with respect to  FIG. 13 . 
     As illustrated in  FIG. 1B , the pressure sensor  140  may be located next to, instead of below, the input member  110 . Many conventional button sensors require that the sensor be placed below the input member  110 , for example in a stack. The button assemblies described herein do not require such an arrangement, and therefore, the thickness of the button assembly can be reduced compared to conventional designs. 
     In various embodiments, button assemblies  102  may include multiple compression chambers  130  and/or multiple pressure sensors  140 , as discussed below with respect to  FIGS. 4-5 . Additionally, button assemblies  102  may include one or more reference chambers and/or reference pressure sensors to determine a differential pressure. This may lead to more effective input detection because the differential pressure can account for atmospheric temperature and pressure changes. This is discussed in more detail below with respect to  FIGS. 2D and 3 . 
     In one embodiment, the compression chamber  130  may include one or more valves configured to fluidly couple the compression chamber  130  with one or more volumes (e.g., reference chambers, enclosed volumes, and/or the atmosphere). The valve may be configured to equalize the pressure in the compression chamber  130  and the coupled volume when the valve is opened. In one embodiment, a valve is configured to fluidly couple the compression chamber  130  to the atmosphere when the valve is opened such that the pressure in the compression chamber  130  adjusts to atmospheric pressure. In another embodiment, the valve couples the compression chamber  130  to a reference chamber when it is opened such that the pressures between the reference chamber and the compression chamber are equalized. In other embodiments, the valve is configured to control the flow of fluid and/or can be closed prior to the pressures equalizing such that the pressures move toward equilibrium, but do not completely equalize. For example, a valve to the atmosphere may allow some air to exit the compression chamber  130 , but may be closed before the compression chamber  130  reaches atmospheric pressure. 
     In one embodiment, the device housing  104  defines an enclosed volume  105 , and may include a passage between the enclosed volume  105  and the opening  106  such that the button assembly  102  and additional components of the electronic device  100  may be physically coupled, for example by an electrical connector  150 . For example, the pressure sensor  140  may be electrically connected to a processor of the electronic device  100  via the electrical connector  150 . The electrical connector  150  is illustrated as a flex cable, but may be any suitable electrical connector for facilitating communication between the button assembly  102  and components of the electronic device  100 , such as wire, cable, and the like. In one embodiment, the button assembly  102  and additional components of the electronic device  100  are coupled using a wireless connection. 
     In one embodiment, the input member  110  is configured to translate, for example up and down with respect to  FIG. 1B , in response to inputs on the input surface. In other embodiments, the input member  110  may be configured to bend as a beam (e.g., a fixed-free beam or a fixed-fixed beam) attached to the button housing  120  or the device housing  104 , and is configured to deflect or bend in response to user input. The input member  110  may also bend or deform as a diaphragm or flexible wall. In other embodiments, the input member  110  may be configured to twist or rotate. 
     In the example of  FIG. 1B , the input member  110  is shown as a separate component that is attached to the button housing  120 , but in various embodiments, the input member  110  may be integrated as an exterior surface of the button housing  120 , or it may be a separate component disposed on, within, or outside of the button housing  120 . In the case in which the input member  110  is integrated as an exterior surface of the button housing, the button housing may define the input surface. The input member  110  may comprise one or more layers. In one embodiment, an outer layer is a cap formed of a durable material such as sapphire, and the cap forms an exterior surface of the button housing  120 . 
     The button housing  120  houses various button assembly components. In various embodiments, the button housing  120  is configured to be attached to or disposed in an opening  106  of the housing  104  of the electronic device. The button assembly  102  may be attached to the device housing  104  using a variety of methods, including fasteners (e.g., screws, bolts, clips, and so on), adhesives, welding, pressure fitting, and the like. 
     In various embodiments, the button assembly  102  is self-contained or modular. For example, as described above, the button assembly  102  may include a button housing  120  that houses various button assembly components and is configured to be attached to or disposed in the housing  104  of the electronic device. The modular nature of the button assembly provides several advantages. The button assembly  102  may be installed and removed easily. Further, the manufacturing process of an electronic device may be simplified because the button assembly  102  can be constructed separately from the rest of the device and installed in a relatively quick and simplified manner as compared to, for example, a traditional button assembly with components that are integrated into a device housing. The button assembly  102  may further be tested separately from the rest of the device, both during and after construction, which simplifies quality assurance and troubleshooting. The button assembly  102  may be removed from the assembly for testing and/or replacement, which may reduce device maintenance complexity and cost. The modular nature of the button assembly  102  also allows the button assembly and the housing  104  of the electronic device in which the button assembly is disposed to be sealed, thereby inhibiting the entry of moisture or contaminants into the device housing  104  and/or the button assembly. 
     In one embodiment, the button assembly  102  is configured to produce a tactile output. For example, the button assembly provides feedback in response to a sensed touch, to confirm an input, and so on. In one embodiment, the button assembly  102  includes a sensor, such as a touch sensor, a biometric sensor, a contact sensor, a capacitive sensor, or the like. For example, the button assembly may detect whether a user&#39;s finger, skin, or other object is contacting the input surface of the input member  110 . 
     As shown in  FIG. 1B , the button assembly  102  may be positioned to protrude from a surface of the device housing  104 . Alternatively, the button assembly may be positioned such that it is flush with a surface of the device housing  104  to present a substantially planar input member relative to the surface of the electronic device. In yet another alternative, the button assembly may be positioned to be recessed in a surface of the device housing  104 . Other configurations of the mounting of the button assembly are possible. For example, the exterior of the button assembly may be conformal with an adjacent exterior surface of the device housing, or may be depressed with respect to an adjacent surface of the device housing. 
       FIG. 2A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. The button assembly  202  is similar to the button assembly  102  of  FIG. 1 , and includes a pressure sensor  240  that is configured to detect changes in pressure in a compression chamber  230 . As noted above, the pressure changes detected by the pressure sensor  240  may be interpreted as inputs by the electronic device. In the embodiment of  FIG. 2A , the button assembly  202  includes a shaft  212  that extends at least partially into the compression chamber  230 . The shaft  212  is coupled to an input member  210 . The shaft  212  and the input member  210  are configured to translate up and down (with respect to  FIG. 2A ). As the input member  210  and the shaft  212  translate, the shaft  212  is configured to move up and down within the compression chamber  230 , thereby changing the volume of the compression chamber. The compression chamber  230  is sealed such that, as the shaft  212  moves, the pressure in the compression chamber changes according to Boyle&#39;s law. Accordingly, when a user exerts a force (e.g., presses, pulls, and so on) on the input member  210  that causes the shaft  212  to move, the pressure sensor  240  detects a change in pressure that may be interpreted as an input by the electronic device. 
     In the example of  FIG. 2A , the input member  210  and the shaft  212  are in a neutral or default position, in which no force is being applied to move the input member  210 .  FIG. 2B  illustrates the cross-section of  FIG. 2A  with the input member  210  in a depressed position, for example as a result of a downward force  290  being applied to the input member  210  (e.g., a press of the input member). The input member  210  is depressed into an opening  234  of the button housing  220 , and the shaft  212  is depressed into a passage  231  of the compression chamber  230 . As a result, the volume of the compression chamber  230  is reduced, and pressure in the compression chamber is increased compared to the neutral position. The pressure increase may be detected by the pressure sensor  240  and registered as an input (e.g., a press of the button) by the electronic device. 
       FIG. 2C  illustrates the cross-section of  FIGS. 2A-2B  with the input member  210  in an extended position, for example as a result of an upward force  292  being applied to the input member  210  (e.g., a pull of the input member). The shaft  212  is moved upward within the passage  231 , thereby increasing the volume of the compression chamber  230 . As a result, the pressure in the compression chamber  230  is decreased compared to the neutral position. In various embodiments, the input member  210  and shaft  212  may return to a default position (e.g., the default position of  FIG. 2A ) when an applied force is removed. 
     As noted above, the shaft  212  is configured to move in and out of the compression chamber  230 , thereby changing its volume. In one embodiment, the shaft  212  is coupled to the input member  210 . In another embodiment, the shaft  212  and the input member  210  are integrated as a single part. The shaft  212  may be a bar having a generally cylindrical shape and made of any suitable material including metals (e.g., aluminum, titanium, and the like), polymers, and so on. 
     As illustrated in  FIG. 2C , the shaft  212  may include a collar  216  configured to retain the shaft and the input member  210  in the button housing  220  when the shaft is in an extended position. In the illustration of  FIG. 2C , the collar  216  is positioned at a bottom end of the shaft  212  such that the collar cannot move past the seal  214 , thus retaining the shaft and input member  210  in the button housing  220 . In various embodiments, different retention mechanisms may be used to retain the shaft and/or the input member in the button housing  220 . 
     In one embodiment, the seal  214  is disposed between the shaft  212  and a surface of the button housing  220 . The seal  214  is configured to provide an airtight seal of the compression chamber  230 , for example to contain the contents of the compression chamber  230  and/or exclude contaminants (e.g., dirt, liquids, and so on) from the compression chamber. In one embodiment, the seal  214  is an O-ring seal disposed around the shaft  212 , and the seal is compressed between the shaft  212  and a surface of the button housing  220  such that the compression chamber  230  is sealed. The seal  214  is shown as a single O-ring seal for purposes of illustration, but in various embodiments, the seal  214  may be any type of mechanical seal, adhesive, seal, or the like, including but not limited to, gaskets, O-rings, face seals, plugs, washers, and the like. Additionally, multiple seals  214  may be used to seal the compression chamber  230 . 
     In one embodiment, the seal  214  is attached to the shaft  212  and is configured to move relative to the button housing  220  as the shaft  212  moves. In another embodiment, the seal  214  is attached to the button housing  220  such that the shaft  212  moves relative to the button housing  220  and the seal  214 . 
     The pressure sensor  240  is operably coupled to the compression chamber  230  and configured to output a signal in response to the pressure changing in the compression chamber  230 . As noted above, the signal indicating a pressure change may be interpreted by the electronic device as an input. The pressure sensor may be configured to measure pressure changes, absolute pressure and/or differential pressure. In various embodiments, the pressure sensor  240  may measure pressure and/or pressure changes using a variety of methods and techniques, including piezoresistive strain gauge, capacitive, electromagnetic, piezoelectric, optical, potentiometric, and so on. 
     In the embodiment of  FIG. 2A , the pressure sensor  240  is at least partially disposed within the button housing  220 . In various embodiments, the pressure sensor  240  may be disposed at any suitable location within the button assembly  202 , the electronic device, or some combination thereof. As shown in  FIG. 2A , the device housing  204  defines an enclosed volume  205 , and may include a passage  253  between the enclosed volume  205  and the opening  206  such that the button assembly  102  and additional components of the electronic device may be physically coupled, for example by an electrical connector  250 . For example, the pressure sensor  240  may be electrically connected to a processor of the electronic device via the electrical connector  250 . The electrical connector  250  is illustrated as a flex cable, but may be any suitable electrical connector for facilitating communication between the button assembly  202  and components of the electronic device, such as wire, cable, and the like. 
     The electrical connector  250  may be coupled to the pressure sensor  240  directly or indirectly. For example, as shown in  FIG. 2A , the electrical connector  250  is coupled to the pressure sensor  240  via a contact  252  disposed near an opening of the passage  253 . In various embodiments, the contact  252  is configured to interface with the pressure sensor  240  and the electrical connector  250 . The contact  252  may be integrated with the pressure sensor  240 , the button housing  220 , the electrical connector  250 , and/or the device housing  204 , or it may be a separate component. 
     The button housing  220  houses various button assembly components. In various embodiments, the button housing  220  is configured to be attached to or disposed in an opening  206  of the housing  204  of the electronic device. The button assembly  202  may be attached to the device housing  204  using a variety of methods, including fasteners (e.g., screws, bolts, clips, and so on), adhesives, welding, pressure fitting, and the like. 
     As shown in  FIG. 2A , the button housing  220  may include one or more outer portions  222  that act as a wing, flange, or collar for disposing the button housing  220  in the device housing  204 . In one embodiment, the outer portions  222  are configured to rest on a shelf of the device housing  204 . In various embodiments, the button housing  220  is attached to the device housing  204  at the outer portions  222 . 
     As noted above, the button assembly may include one or more reference chambers configured to provide a reference pressure for comparison with the pressure in the compression chamber.  FIG. 2D  is a cross section of the button assembly  202 , including a reference chamber  232 , taken through section line B-B of  FIG. 2A . In the example of  FIG. 2D , the reference chamber  232  is coupled to the pressure sensor  240 . The pressure sensor  240  may be a differential or sealed pressure sensor that is configured to compare the pressure in the compression chamber to the pressure in the reference chamber to detect a difference between the compression chamber and the reference chamber. Additionally or alternatively, the pressure sensor  240  may be an absolute pressure sensor configured to determine an absolute pressure in the compression chamber  230  and the reference chamber  232 . In other embodiments, separate pressure sensors may be used to determine the pressure and/or change in pressure within the compression chamber  230  and the reference chamber  232 . In the embodiment of  FIG. 2D , one compression chamber  230  and one reference chamber  232  are illustrated, however in practice any number of compression chambers and reference chambers may be used. 
     Similar to the button assembly  102 , the compression chamber  230  and/or the reference chamber  232  may include one or more valves configured to fluidly couple the compression chamber  230  and/or the reference chamber  232  with one another, with other chambers, enclosed volumes and/or the atmosphere. In one embodiment, a valve is configured to fluidly couple the compression chamber  230  with the reference chamber  232  such that when the valve is opened, the pressures equalize or move toward equilibrium. 
       FIG. 3A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. The button assembly  302  is similar to the button assemblies  102 ,  202  discussed above. In the embodiment of  FIG. 3A , the reference chamber  332 , the pressure sensor  340 , and a portion  330 A of the compression chamber is located in the input member  310 . The button assembly  302  includes a shaft  312  that is integrated with the input member  310 . A portion  330 B of the compression chamber is located in the shaft  312  and couples the portion  330 A with a portion  330 C in the button housing  320 . As the input member  310  and shaft  312  move up and down relative to the button housing  320 , the volume of the sealed compression chamber  330  changes and the pressure changes as a result. The pressure sensor  340  is fluidly coupled to the compression chamber  330  and the reference chamber  332  and is configured to detect pressure differentials, pressure changes and/or pressure values of the compression chamber  330  and the reference chamber  332 . 
     The button assembly  302  includes an electrical connector  350  configured to electrically couple the button assembly  302  to other components of the electronic device, such as a processor. In one embodiment, the electrical connector  350  includes multiple components, including a flex cable  350 A extending through the button housing  320  and/or the device housing  304 . The electrical connector  350  may further include a contact  350 B coupled to the flex cable  350 A. At least a portion of the contact  350 B is positioned between a surface of the button housing  320  and a surface of the shaft  312 .  FIG. 3B  illustrates a removed view of a portion of the example button assembly identified by the enclosed circle  1 - 1  shown in  FIG. 3A . The contact  350 B is configured to maintain an electrical connection with a contact  350 C on the shaft  312  as the shaft moves up and down. In one embodiment, the contact  350 B is disposed within the seal  314 . Returning to  FIG. 3A , the pressure sensor  340  is electrically coupled to the contact  350 C, for example by a connector  350 D disposed within the input member  310 . 
     The button assemblies shown in  FIGS. 2A-3B  include one compression chamber, and one shaft. However, in various embodiments, a button assembly may include multiple compression chambers and/or shafts. The button assembly may further include multiple pressure sensors configured to measure pressure values or pressure changes within each compression chamber. The outputs of the multiple pressure sensors may be used to determine additional information about an input, including a position of the input on an input surface, a direction of an input, and so on. 
       FIG. 4  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. The button assembly  402  is similar to the button assemblies discussed above. The button assembly  402  includes multiple shafts  412 , compression chambers  430 , and pressure sensors  440 . In the embodiment of  FIG. 4 , two shafts  412 A and  412 B are shown. Each shaft  412  is configured to move relative to a respective compression chamber  430 , thereby changing the volume of the compression chamber. Each compression chamber  430 A and  430 B is coupled to a pressure sensor  440 . The pressure sensors  440 A and  440 B are configured to measure pressure values or pressure changes within each compression chamber. In the embodiment of  FIG. 4 , the two outputs of the two pressure sensors  440  can be used to determine an angle or tilt of the input member  410  in response to an input and/or a position of the input on the input member. The ability to determine a tilt or angle of the input member  410  makes the button assembly  402  suitable for a toggle switch, rocker switch, or the like. The button assembly  402  further includes seals  414 A and  414 B disposed between the shafts  412 A and  412 B and respective surfaces of the button housing  420 . The seals  414  are similar to the seals  214 ,  314  discussed above. 
       FIG. 5  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment.  FIG. 5  shows a top-down cross-section similar to the cross-section of  FIG. 2D  of a button assembly  502  with four shafts  512 A-D, four compression chambers  530 A-D, and four pressure sensors  540 A-D. A button housing  520  of the button assembly  502  may be disposed in an opening of a device housing  504  as described above. Similar to the embodiments described above, each shaft  512  is configured to move relative to a respective compression chamber  530 , thereby changing the volume of the compression chamber. Each pressure sensor  540  is coupled to a respective compression chamber  530  and configured to measure pressure values or pressure changes within the coupled compression chamber. The outputs of the pressure sensors  540  may be used to determine an angle or tilt of an input surface in two dimensions (e.g., up-down and right-left with respect to  FIG. 5 ). The ability to determine a tilt or angle of the input surface in two dimensions makes the button assembly  502  suitable for a directional button, a joystick, or the like. 
     The button assembly  502  includes various components that are similar to those discussed with respect to other embodiments. For example, the button assembly  502  includes electrical connectors  550 A-D for coupling the pressure sensors  540  to other components of the electronic device. The button assembly  502  further includes seals  514 A-D disposed between the shafts  512 A-D and respective surfaces of the button housing  520 . The seals  514  are similar to the seals  214 ,  314 ,  414  discussed above. 
       FIG. 6A  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. The button assembly  602  is similar to the button assemblies discussed above. A button housing  620  of the button assembly  602  may be disposed in an opening of a device housing  604  as described above. The button assembly  602  includes a flexible membrane  616  that defines a wall of the compression chamber  630 . In the embodiment of  FIG. 6 , the flexible membrane  616  is disposed in a passage  631  of the button housing  620 . The button assembly includes an input member  610  and a shaft  612  that are configured to translate similar to the input members and shafts discussed above (e.g., input member  210  and shaft  212 ). The flexible membrane  616  is configured to deform, deflect, or bend in response to the shaft  212  translating and exerting a force on the flexible membrane. The flexible membrane  616  further forms a seal that contains the contents of the compression chamber  630 . 
       FIG. 6B  illustrates the input member  610  and the shaft  612  translated downward (with respect to  FIG. 6B ), for example as a result of a force applied to the input member  610 . The movement of the shaft  612  results in the flexible membrane  616  deforming and thereby reducing the volume of the compression chamber  630  and increasing the pressure in the chamber. Similar to the pressure sensors described above, the pressure sensor  640  is configured detecting pressure values and/or pressure changes and output a signal that may be interpreted as an input. In one embodiment, the flexible membrane  616  causes the shaft  612  and the input member  610  to return to a default position (e.g., the position of  FIG. 6A ) when an applied force is removed. 
     The flexible membrane  616  may be attached to the shaft  612 , for example by an adhesive, such that the flexible membrane deforms upward when the shaft  612  moves upward from the default position of  FIG. 6A , for example as a result of an upward force being applied to the input member  610 . The flexible membrane  616  deforming upward increases the volume of the compression chamber  630 , thereby reducing the pressure in the compression chamber. This pressure change may be detected by the pressure sensor  640  interpreted as an input. 
     The button assembly  602  includes various components that are similar to those discussed with respect to other embodiments. For example, the button assembly  602  includes electrical connector  650  and contact  652  for coupling the pressure sensor  640  to other components of the electronic device. 
     As discussed above, some button assemblies include functionality for providing tactile feedback or tactile outputs to users.  FIG. 7  is a cross-section of an example button assembly disposed in an opening of an electronic device, according to an embodiment. The button assembly  702  is similar to the button assemblies discussed above, and may be disposed in a device housing  704  as shown in  FIG. 7 . The button assembly  702  includes a pressure change actuator  742  configured to change the pressure in the compression chamber  730 , for example to provide tactile output through the input member  710 . In the example of  FIG. 7 , the button housing  720  includes a pressure chamber  736  coupled to the pressure change actuator  742 . The pressure change actuator  742  is configured to change the pressure in the pressure chamber  736 , creating a pressure differential between the compression chamber  730  and the pressure chamber  736 . The pressure chamber  736  is coupled to the compression chamber  730  via a valve  760 . The valve  760  is configured to fluidly couple the compression chamber  730  and the pressure chamber  736  when opened, thereby equalizing or moving toward equilibrium the pressures in the two chambers. 
     In one embodiment, the pressure change actuator  742  increases the pressure in the pressure chamber  736  such that when the valve  760  is opened, the pressure changes (increases or decreases) in the compression chamber  730 , resulting in a force being applied the shaft  712  and the input member  710  (upward or downward with respect to  FIG. 7 ). This force may be felt by a user as a tactile output. In one embodiment, the valve may be opened during movement of the shaft  712  and the input member  710  such that the user perceives a change in resistance of movement of the input member  710 . In various embodiments, the resistance of the movement of the input member  710  may mimic the behavior of a mechanical switch. 
     In another embodiment, the pressure change actuator  742  is configured to change the pressure in the compression chamber  730 , for example to set the pressure in the compression chamber to a desired level. This may be used to account for changes in temperature, atmospheric pressure, and the like that result in changes in the pressure of the compression chamber  730 . 
     The pressure change actuator  742  may be operably coupled to additional components of the electronic device and/or the pressure sensor  740 , for example via one or more electrical connectors  750 ,  751 . The electrical connectors  750 ,  751  are illustrated as flex cables, but may be any suitable electrical connectors for facilitating communication between the button assembly  702  and components of the electronic device, such as wire, cable, and the like. In one embodiment, the pressure change actuator  742  is controlled by a processor of the electronic device. 
     The button assembly  702  includes various components that are similar to those discussed with respect to other embodiments. For example, the button assembly  702  includes a seal disposed between the shaft  712  and a surface of the button housing  720 . The seals  714  are similar to the seals  214 ,  314 ,  414 ,  514  discussed above. 
     As described above, a button assembly may be disposed in any electronic device. In one embodiment, the button assembly is disposed in a wearable electronic device such as a watch.  FIG. 8  illustrates an example wearable electronic device  800  that may incorporate one or more button assemblies as described herein. 
     In the illustrated embodiment, the electronic device  800  is implemented as a wearable computing device (e.g., an electronic watch). Other embodiments can implement the electronic device differently. For example, the electronic device can be a smart telephone, a gaming device, a digital music player, a device that provides time, a health assistant, and other types of electronic devices that include, or can be connected to a sensor(s). 
     In the embodiment of  FIG. 8 , the wearable electronic device  800  includes a device housing  804  at least partially surrounding a display  811 , a watch crown  808 , and one or more buttons  802 . The wearable electronic device  800  can also include one or more internal components (not shown) typical of a computing or electronic device, such as, for example, one or more processors, memory components, network interfaces, and so on. 
     Returning to  FIG. 8 , the watch crown  808 , the button  802 , or both may be implemented as button assemblies as described herein. The watch crown  808  and the button  802  are disposed in a sidewall of the device housing  804 , and are permanently or releasably attached to the device housing. 
     The device housing  804  provides a device structure, defines an internal volume of the wearable electronic device, and houses device components. In various embodiments, the device housing  804  may be constructed from any suitable material, including metals (e.g., aluminum, titanium, and the like), polymers, ceramics (e.g., glass, sapphire), and the like. In one embodiment, the device housing  804  is constructed from multiple materials. The device housing  804  can form an outer surface or partial outer surface and protective case for the internal components of the wearable electronic device  800 , and may at least partially surround the display  811 . The device housing  804  can be formed of one or more components operably connected together, such as a front piece and a back piece. Alternatively, the device housing  804  can be formed of a single piece operably connected to the display  811 . 
     The display  811  can be implemented with any suitable technology, including, but not limited to liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. The display  811  provides a graphical output, for example associated with an operating system, user interface, and/or applications of the electronic device  800 . In one embodiment, the display  811  includes one or more sensors and is configured as a touch-sensitive (e.g., single-touch, multi-touch) and/or force-sensitive display to receive inputs from a user. In various embodiments, a graphical output of the display  811  is responsive to inputs provided to the button  802  and/or the watch crown  808 . 
     The watch crown  808  receives inputs, for example from a user. In one embodiment, the watch crown  808  is configured to rotate about an axis and translate along the axis in response to manipulation. The watch crown  808  may further include a switch such as a dome switch to provide a tactile response to translation of the watch crown. In some embodiments, a button assembly may be integrated with the watch crown  808  such that the watch crown has some or all of the characteristics of the button assemblies described herein. 
     The wearable electronic device  800  can be permanently or removably attached to a band  880 . The band may be used to attach the wearable electronic device  800  to the body of a user. The band can be made of any suitable material, including, but not limited to, leather, metal, rubber or silicon, fabric, and ceramic. In the illustrated embodiment, the band is a wristband that wraps around the user&#39;s wrist. The wristband can include an attachment mechanism, such as a bracelet clasp, Velcro, and magnetic connectors. In other embodiments, the band can be elastic or stretchable such that it fits over the hand of the user and does not include an attachment mechanism. 
       FIG. 9A  is a cross-section of a watch crown  908  disposed in an opening of the wearable electronic device  800  taken through section line C-C of  FIG. 8 . The watch crown  908  includes a button housing  920  and an input member  910  that is configured to receive rotational inputs. The input member  910  is coupled to a shaft  912  that extends into an opening of the button housing  920 . The shaft  912  includes an arm  960  that is configured to change the volume of a compression chamber  930  responsive to torque (e.g., a rotational force) applied to the input member  910 . In one embodiment, the watch crown  908  is disposed in a device housing  904 , which is similar to the device housing  804  discussed above with respect to  FIG. 8 . 
       FIG. 9B  is a cross-section of the watch crown  908  taken through section line D-D of  FIG. 9A . The arm  960  forms at least a part of a wall of the compression chamber  930  such that when the shaft  912  rotates causing the arm  960  to move, the volume of the compression chamber  930  increases or decreases. As described above, a pressure sensor  940  is configured to detect the change in pressure, which may then be interpreted as an input. 
       FIG. 9C  illustrates the cross-section of  FIG. 9B  with the arm  960  displaced in response to a torque applied in the clockwise direction. As shown in  FIG. 9B , the volume of the compression chamber  930  is reduced as a result of the movement of the arm  960 , and the pressure in the compression chamber is increased compared to the neutral position of  FIG. 9B . The pressure increase may be detected by the pressure sensor  940  and registered as an input by the wearable electronic device  900 . 
       FIG. 9D  illustrates the cross-section of  FIG. 9B  with the arm  960  displaced in response to a torque applied in the counter-clockwise direction. As shown in  FIG. 9C , the volume of the compression chamber  930  is increased as a result of the movement of the arm  960 , and the pressure in the compression chamber is decreased compared to the neutral position of  FIG. 9B . The pressure decrease may be detected by the pressure sensor  940  and registered as an input by the wearable electronic device  900 . In various embodiments, the arm  960  may return to a default position (e.g., the default position of  FIG. 9B ) when an applied force is removed. 
     A seal  964  seals the compression chamber. The seal  964  is disposed around the arm  960  and is formed of a compliant material such that the arm can move. As shown in  FIGS. 9A and 9B , a compliant member  962  is disposed between the arm and one or more surfaces of the button housing  920  and is configured to allow the arm  960  to move while maintaining a seal of the compression chamber  930 . In one embodiment, the arm  960  is formed of a compliant material and is configured to deform, flex, or bend, thereby changing the volume of the compression chamber  930 . 
     The watch crown  908  may include a seal  914  for excluding contaminants from entering the button housing  920  and/or retaining the shaft  912  and input member in the button housing. The watch crown  908  may be operably coupled to one or more components of the wearable electronic device  900 , such as a processor, by an electrical connector  950 . 
     In one embodiment, the watch crown  908  includes a second compression chamber and a second pressure sensor that are configured to detect translation (e.g., movement up and down with respect to  FIG. 9A ) of the input member  910  and the shaft  912 . 
     The input member  910  may be configured to rotate relative to the shaft  912 , for example to mimic the operation of a conventional watch crown. The rotational motion may have sufficient resistance such that a torque is applied to the shaft  912  while the input member  910  is rotating so that the arm  960  moves or deflects to change the volume of the compression chamber  930 . 
       FIG. 10  is a cross-section of a watch crown  1008  disposed in an opening of a wearable electronic device according to an embodiment. The watch crown  1008  includes a threaded shaft  1012  coupled to an input member  1010 . A button housing  1020  includes a compression chamber  1030 . The threads of the shaft  1012  are configured to convert rotational motion of the input member  1010  and shaft  1012  to linear motion of the input member and shaft (up and down with respect to  FIG. 10 ). As the shaft  1012  moves up and down, it changes the volume of the compression chamber  1030 . As discussed above, this results in a change in the pressure in the compression chamber  1030 . A pressure sensor  1040  is configured to detect the pressure change, which may be registered as an input by the wearable electronic device. In one embodiment, the watch crown  1008  is disposed in a device housing  1004 , which is similar to the device housing  804  discussed above with respect to  FIG. 8 . 
     The watch crown  1008  includes various components that are similar to those discussed with respect to other embodiments. For example, the watch crown  1008  includes an electrical connector  1050  for coupling the pressure sensor  1040  to other components of the electronic device. 
     Various embodiments described herein include a button housing and/or a compression chamber defined by or disposed within a button housing. In other embodiments, the compression chamber may be positioned at a different location of an electronic device.  FIG. 11  is a cross-section of an example button assembly  1102 , according to an embodiment. In the example of  FIG. 11 , the button assembly  1102  does not include a button housing, and the compression chamber  1130  is defined by an opening in a device housing  1104  that is sealed by a seal  1114  and a shaft  1112 . The shaft  1112  is coupled to or integrated with an input member  1110  and is configured to move responsive to forces applied at the input member. The button assembly  1102  further includes a pressure sensor coupled to the compression chamber  1130  and disposed in the device housing  1104 . The pressure sensor is coupled to other components of the electronic device via an electrical connector  1150 . Similar to the button assemblies described above, movement (e.g., up and down with respect to  FIG. 11 ) of the shaft  1112  causes the volume of the compression chamber  1130  to change. As discussed above, this results in a change in the pressure in the compression chamber  1130 . A pressure sensor  1140  is configured to detect the pressure change, which may be registered as an input by the electronic device. 
     The button assembly  1102  includes various components that are similar to those discussed with respect to other embodiments. For example, the button assembly  1102  includes a collar  1116  configured to retain the shaft and the input member  1110  in the device housing  1104  when the shaft is in an extended position. The collar  1116  is similar to the collars (e.g., collar  216 ) discussed above. 
       FIG. 12  is a cross-section of an example button assembly  1202 , according to an embodiment. The button assembly  1202  includes a button housing  1220  disposed in an opening of a device housing  1204 . In one embodiment, the button housing  1220  and the device housing  1204  cooperatively define at least a part of the compression chamber  1230 . For example, in the example of  FIG. 12 , the compression chamber  1230  is formed between the button housing  1220  and the device housing  1204 . The button assembly  1202  includes a seal  1215  (e.g., a gasket seal) disposed between the button housing  1220  and the device housing  1204  to seal the compression chamber  1230 . 
     The button assembly  1202  includes various components that are similar to those discussed with respect to other embodiments. For example, the button assembly  1202  includes a pressure sensor  1240  that is similar to the pressure sensors (e.g., pressure sensor  240 ) described herein. The button assembly  1202  further includes a shaft  1212  that is similar to the shafts (e.g., shaft  212 ) discussed herein. The button assembly  1202  additionally includes an input member  1210  that is similar to the input members (e.g., input member  210 ) described herein. The button assembly  1202  still further includes an electrical connector  1250  that is similar to the electrical connectors (e.g., electrical connector  250 ) described herein. The button assembly  1202  additionally includes a seal  1214  that is similar to the seals (e.g., seal  214 ) described herein. 
       FIG. 13  is a simplified flow chart depicting example operations of a processor of an electronic device with a button assembly as described herein. The method  1300  may be used to determine whether a change in pressure in a compression chamber is registered or detected as an input by the electronic device. In addition to the pressure in the compression chamber changing based on a change in the volume of the compression chamber as discussed above, in various embodiments, the pressure in a compression chamber may change based on factors that are not a result of a user input, such as changes in temperature, atmospheric pressure, and the like. A processor of the electronic device can determine, based on characteristics of a pressure change, whether a change in pressure is a result of a user input. 
     The method  1300  includes operation  1310  in which a pressure sensor detects a change in pressure in a compression chamber. Next, at operation  1320 , a processor of the electronic device determines whether the magnitude of the change in pressure exceeds a threshold. If the magnitude of the change in pressure does not exceed the threshold, then the process returns to operation  1310  and pauses until another change in pressure is detected. If the pressure change does exceed the threshold, then the process proceeds to operation  1330 , in which the processor determines whether the rate of the change in pressure exceeds a threshold. If the rate of the change in pressure does not exceed the threshold, then the process returns to operation  1310  and pauses until another change in pressure is detected. If the rate of the change in pressure does exceed the threshold, then the process proceeds to operation  1340  in which the processor registers an input. 
     The processor of the electronic device may process the input and may trigger various actions at the electronic device responsive to receiving the input. For example, the processor may execute computer-readable instructions such as performing operations within applications, an operating system, a user interface, and the like. 
     In various embodiments, the steps of method  1300  are performed in a different order or with more or fewer steps. For example, in one embodiment, one or more of operations  1320  and  1330  may be omitted from the method. 
     As noted above, many embodiments described herein reference a force-sensing input device for use as part of an electronic device. It may be appreciated, however, that this is merely one example; other configurations, implementations, and constructions are contemplated in view of the various principles and methods of operation—and reasonable alternatives thereto—described in reference to the embodiments described above. 
     For example, without limitation, a force-sensing input device can be additionally or alternatively associated with: a display surface, a housing or enclosure surface, a planar surface, a curved surface, an electrically conductive surface, an electrically insulating surface, a rigid surface, a flexible surface, a key cap surface, a trackpad surface, a display surface, and so on. The interface surface can be a front surface, a back surface, a sidewall surface, or any suitable surface of an electronic device or electronic device accessory. Typically, the interface surface of a multimode force interface is an exterior surface of the associated portable electronic device but this may not be required. 
     Further, although many embodiments reference a force-sensing input device in a portable electronic device (such as a cell phone or tablet computer) it may be appreciated that a force-sensing input device can be incorporated into any suitable electronic device, system, or accessory including but not limited to: portable electronic devices (e.g., battery-powered, wirelessly powered devices, tethered devices, and so on); stationary electronic devices; control devices (e.g., home automation devices, industrial automation devices, aeronautical or terrestrial vehicle control devices, and so on); personal computing devices (e.g., cellular devices, tablet devices, laptop devices, desktop devices, and so on); wearable devices (e.g., implanted devices, wrist-worn devices, eyeglass devices, and so on); accessory devices (e.g., protective covers such as keyboard covers for tablet computers, stylus input devices, charging devices, and so on); and so on. 
     Although specific electronic devices are shown in the figures and described herein, the force-sensing input devices described herein may be used with various electronic devices, mechanical devices, electromechanical devices and so on. Examples of such include, but are not limited to, mobile phones, personal digital assistants, time keeping devices, health monitoring devices, wearable electronic devices, input devices (e.g., a stylus, trackpads, buttons, switches, and so on), a desktop computer, electronic glasses, steering wheels, dashboards, bands for a wearable electronic device, and so on. Although various electronic devices are mentioned, the force-sensing input devices disclosed herein may also be used in conjunction with other products and combined with various materials. 
     One may appreciate that although many embodiments are disclosed above, that the operations and steps presented with respect to methods and techniques described herein are meant as exemplary and accordingly are not exhaustive. One may further appreciate that alternate step order or fewer or additional operations may be required or desired for particular embodiments. 
     Although the disclosure above is described in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations, to one or more of the some embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments but is instead defined by the claims herein presented.

Metadata:
Filing Date: 20171024
Publication Date: 20201110
Grant Date: 20201110
Priority Date: 20170816
Inventors: Lukens, William C.
CLAVELLE, Adam T.
CARDINALI, STEVEN P.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0414", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0414", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 73052094