PATENT DOCUMENT

Publication Number: US-9400582-B2
Application Number: US-201514623744-A
Country: US
Kind Code: B2

Title: Touch pad with force sensors and actuator feedback

Abstract:
Electronic devices may use touch pads that have touch sensor arrays, force sensors, and actuators for providing tactile feedback. A touch pad may be mounted in a computer housing. The touch pad may have a rectangular planar touch pad member that has a glass layer covered with ink and contains a capacitive touch sensor array. Force sensors may be mounted under each of the four corners of the rectangular planar touch pad member. The force sensors may be used to measure how much force is applied to the surface of the planar touch pad member by a user. Processed force sensor signals may indicate the presence of button activity such as press and release events. In response to detected button activity or other activity in the device, actuator drive signals may be generated for controlling the actuator. The user may supply settings to adjust signal processing and tactile feedback parameters.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having an opening defined therein; and 
 a track pad disposed within the opening of the housing, the track pad comprising:
 a contact surface; 
 a capacitive touch sensor disposed below the contact surface and configured to detect the location of a touch on the contact surface; 
 a set of force sensors disposed below the capacitive touch sensor; and 
 an output device configured to output non-visual feedback in response to a force of the touch that exceeds a threshold force on the contact surface of the track pad; 
 
 wherein:
 the trackpad is configured to transfer the force to one or more of the set of force sensors; and 
 the set of force sensors are configured to produce a non-binary output signal that corresponds to the force of the touch on the contact surface. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein:
 the output device includes a speaker; and 
 the output device is configured to produce an audio output in response to a force exerted on the contact surface. 
 
     
     
       3. The electronic device of  claim 1 , wherein the set of force sensors are configured to produce an analog output signal that is linearly or non-linearly proportional to the force of the touch. 
     
     
       4. The electronic device of  claim 1 , wherein each force sensor of the set of force sensors includes at least one bendable member that is configured to bend in response to a force applied to the contact surface and produce an output that corresponds to an amount of deflection due to the force. 
     
     
       5. The electronic device of  claim 1 , wherein:
 each force sensor of the set of force sensors includes metalized traces formed on a surface of a substrate disposed below the contact surface; and 
 the metalized traces form interdigitated fingers that deflect in response to a force on the contact surface. 
 
     
     
       6. The electronic device of  claim 1 , wherein:
 the set of force sensors include a capacitive sensor having two electrodes; and 
 the force sensor is configured to measure the force on the contact surface of the track pad based on a change in capacitance between the two electrodes. 
 
     
     
       7. The electronic device of  claim 1 , wherein:
 the track pad is coupled to a housing wall by a spring member and 
 the housing wall is coupled to the housing. 
 
     
     
       8. The electronic device of  claim 7 , wherein:
 the housing wall is formed from a metal plate; and 
 the spring member is integrally formed with the housing wall. 
 
     
     
       9. The electronic device of  claim 1 , further comprising processing circuitry configured to:
 determine whether or not a user input includes a gesture;
 in accordance with a determination that a user input does not include a gesture, apply a first force threshold associated with a first input command; and 
 in accordance with a determination that the user input includes a gesture, apply a second force threshold associated with a second input command; wherein the first threshold is less than the second threshold. 
 
 
     
     
       10. The electronic device of  claim 9 , wherein the processing circuitry is further configured to:
 in accordance with a determination that the user input includes a gesture, inhibit a response to a user press input. 
 
     
     
       11. The electronic device of  claim 10 , wherein the gesture comprises an object moving across the contact surface. 
     
     
       12. A portable computer comprising:
 a housing; 
 a display disposed with the housing; 
 a keyboard disposed with the housing; and 
 a track pad disposed within an opening in the housing and positioned along a side of the keyboard, the track pad comprising:
 a contact surface; 
 a capacitive touch sensor disposed below the contact surface and configured to detect the location of a touch on the contact surface; 
 a set of force sensors disposed below the contact surface in a layer separate from the capacitive touch sensor, wherein: 
 each force sensor is positioned proximate to a different corner of the track pad; and 
 the set of force sensors are configured to produce a non-binary output signal that corresponds to a force on the contact surface. 
 
 
     
     
       13. The portable computer of  claim 12 , wherein each force sensor includes a set of interdigitated fingers that deflect in response to a force on the contact surface. 
     
     
       14. The portable computer of  claim 12 , further comprising:
 a housing wall coupled to the housing and coupled to the track pad by four spring members. 
 
     
     
       15. The portable computer of  claim 14 , wherein the housing wall is formed from a metal sheet and the four spring members are integrally formed into the metal sheet of the housing wall. 
     
     
       16. The portable computer of  claim 12 , wherein the track pad is configured to reject input from a palm when the keyboard is in use. 
     
     
       17. A method of receiving a user input on a surface of a track pad, the method comprising:
 producing a location output that corresponds to a location of a touch on a contact surface of the track pad using a capacitive touch sensor disposed below the contact surface; 
 producing an analog force output in response to the touch on the contact surface of the track pad using a set of force sensors positioned below the capacitive touch sensor and proximate to respective corners of the track pad, the track pad configured to transfer force at the location of the touch to the set of force sensors; 
 determining an average applied force by averaging the analog force output from the set of force sensors; 
 triggering a button press event if the average applied force exceeds a threshold; and 
 outputting a non-visual feedback in response to the button press event. 
 
     
     
       18. The method of  claim 17 , wherein the threshold is a variable, user-determined threshold. 
     
     
       19. The method of  claim 17 , further comprising:
 recognizing a gesture command if the touch is moving across the contact surface of the track pad; and 
 in accordance with a determination that the user input includes a gesture command, increasing the threshold. 
 
     
     
       20. The method of  claim 17 , further comprising:
 recognizing a gesture command if the touch is moving across the contact surface of the track pad; and 
 in accordance with a determination that the user input includes a gesture command, inhibiting a button press event.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation patent application of U.S. patent application Ser. No. 14/097,145, filed Dec. 4, 2013 and titled “Touch Pad with Force Sensors and Actuator Feedback,” which is a continuation patent application of U.S. patent application Ser. No. 14/021,349, filed Sep. 9, 2013 and titled “Touch Pad with Force Sensors and Actuator Feedback,” now U.S. Pat. No. 8,797,295, which is a continuation patent application of U.S. patent application Ser. No. 12/635,614, filed Dec. 10, 2009 and titled “Touch Pad with Force Sensors and Actuator Feedback,” now U.S. Pat. No. 8,633,916, the disclosures of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to touch sensitive input devices, and, more particularly, to touch pads for electronic devices such as portable computers. 
     Electronic devices such as portable computers have touch pads for receiving user input. Touch pads may also be provided in the form of stand-alone components that are connected to computers. 
     Touch pads typically have a rectangular surface that monitors the position of a user&#39;s finger or other external object. A user may interact with a touch pad by controlling the position of the user&#39;s fingertip on the touch pad surface. The touch pad may be used to control the position of a cursor on a computer display screen or to take other suitable actions. In multi-touch touch pad arrangements, the movement of one or more fingers across the surface of the touch pad may be interpreted as a particular command. For example, a swipe of a user&#39;s fingertips across the touch pad may serve as a gesture that directs a computer to advance through a list of items. 
     Touch pads are typically provided with associated buttons. In a typical arrangement, there are one or two switch-based buttons located in front of a touch pad. A user may use the touch pad to position an on-screen cursor. After positioning the cursor in a desired location, the user may press an appropriate one of the buttons. For example, in a one-button configuration, the user may press the button to click on an on-screen option corresponding to the current on-screen cursor location. The portable computer may then respond accordingly. In two-button arrangements, the right hand button may be used for right-click commands. 
     To improve device aesthetics and to provide a larger touch sensor area for making gesture commands, touch pads with integrated button functionality have been developed. In this type of arrangement, the rear edge of the touch pad is provided with a hinge and the front edge of the touch pad is provided with a switch. When a user presses downwards on the touch pad with sufficient force, the touch pad pivots about its rear edge and actuates the switch. 
     While touch pads of this type may often be satisfactory, it can be challenging to operate the integrated button when pressing the touch pad near the rear edge of the touch pad. Challenges can also arise in satisfying a wide range of user expectations relating to touch pad sensitivity and operation. 
     It would therefore be desirable to be able to provide improved touch pads. 
     SUMMARY 
     Electronic devices such as portable computers and other equipment may be provided with touch pads that include force sensors. Tactile feedback may also be provided. 
     A touch pad, which is sometimes referred to as a track pad or computer track pad, may have a planar touch pad member that includes a touch sensor. The planar touch pad member may be formed from layers of material such as clear or opaque glass, an optional layer of opaque ink on the surface of the glass, stiffeners, printed circuit board structures, layers of adhesive, etc. Collectively, the structures of the planar touch pad member generally do not allow light to pass through the touch pad, thereby enhancing the aesthetics of the touch pad and blocking potentially unsightly internal structures from view. If desired, however, display structures may be incorporated into the touch pad (e.g., to provide touch screen functionality or enhanced touch pad functionality). Arrangements in which the touch pad is opaque are sometimes described herein as an example. 
     The touch sensor may be formed from an array of capacitive electrodes, an array of light detectors (e.g., for a shadow-sensing touch sensor), a resistive sensor array, or other touch sensor structures. Using the touch sensor, the locations of one or more external objects such as the fingers of a user may be detected. Touch sensor signals may be used in interpreting gesture-type commands. In a typical gesture, a user moves one or more fingers across the surface of the touch pad. By determining the number of fingers that are moved across the pad and their locations and directions of movement, the gesture can be recognized and appropriate action taken. 
     In addition to processing touch sensor signals to determine the location of touch events, signals from the force sensors may be processed. A rectangular touch pad may have four corners. Force sensors may be mounted under each of the four corners. When a user presses on the surface of the touch pad, the force sensors may pick up four corresponding independent force signals. These force signals may be processed using force signal processing circuitry. For example, the force signals from each of the force sensors may be combined and the combined signal may be compared to force threshold values to identify press and release events. 
     Tactile feedback may be provided using an actuator. The actuator may be controlled by actuator drive signals. As a user of an electronic device interacts with the touch pad, the user may make gestures and perform other touch-related tasks. When the user desires to select an on-screen object or perform other tasks of the type traditionally associated with button actuation events, the user may press downwards against the surface of the track pad. When sufficient force is detected, appropriate action may be taken and drive signals may be applied to the actuator. The actuator may impart movement to the touch pad. For example, the actuator may drive a coupling member into an edge of the planar touch pad member. Flexible pads may be formed under the force sensors to help allow the touch pad member to move laterally (in-plane with respect to the plane of the planar touch pad member) when the actuator is in operation. This may improve actuator efficiency. The actuator may move the touch pad in response to button press and release events or in response to satisfaction of other criteria in the electronic device. 
     Default and user-defined settings may be used to adjust the way in which touch sensor and force sensor signals are processed. For example, touch sensor and force sensor sensitivity levels may be adjusted. The amount and type of tactile feedback that is applied to the touch pad member by the actuator may also be controlled by default and user-defined settings. For example, a user may select which of several drive current waveforms is to be used in driving the actuator. Drive current waveforms may be configured to produce substantially no audible resonances when moving the touch pad, thereby allowing the touch pad to be operated silently. If desired, audible feedback may be provided using speakers or by altering the actuator drive signal to create audible vibrations of the touch pad when appropriate. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with a touch pad in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an interior portion of an illustrative electronic device with a touch pad showing how the touch pad may have force sensors and an actuator for providing feedback in accordance with an embodiment of the present invention. 
         FIG. 3  is an exploded perspective view of an illustrative touch pad in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative force sensor that produces force measurement signals in response to bending in accordance with an embodiment of the present invention. 
         FIG. 5  is a perspective view of an illustrative force sensor that produces force measurement signals in response to sensor compression in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative resistive force sensor in an unloaded state in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative resistive force sensor of the type shown in  FIG. 6  after being placed in a loaded state in accordance with an embodiment of the present invention. 
         FIG. 8  is a perspective view showing how the distance between capacitor plates in a force sensor may be used to produce a force signal in accordance with an embodiment of the present invention. 
         FIG. 9  is a schematic diagram of a resistive force sensor that may be used in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an illustrative actuator that may be used to impart motion to a touch pad in accordance with an embodiment of the present invention. 
         FIG. 11  is a top view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a relatively short lateral coupling member that is connected between the actuator and the touch pad in accordance with an embodiment of the present invention. 
         FIG. 12  is a top view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a relatively short coupling member that is connected to the actuator but that is nominally spaced apart from the touch pad in accordance with an embodiment of the present invention. 
         FIG. 13  is a top view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a relatively long coupling member that is connected between the actuator and the touch pad in accordance with an embodiment of the present invention. 
         FIG. 14  is a top view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a coupling member with a bend that is connected between the actuator and the touch pad in accordance with an embodiment of the present invention. 
         FIG. 15  is a top view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a linkage that has coupling structures that move relative to each other in accordance with an embodiment of the present invention. 
         FIG. 16  is a top view of an illustrative touch pad showing how multiple actuators may be used to impart motion to the touch pad in accordance with an embodiment of the present invention. 
         FIG. 17  is a side view of an illustrative touch pad showing how an actuator may impart motion to the touch pad using a linkage that converts vertical motion into horizontal motion in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional side view of an illustrative touch pad showing how the touch pad may have support structures with bearings and magnetic holding structures in accordance with an embodiment of the present invention. 
         FIG. 19  is a side view of an illustrative touch pad showing how the touch pad may have force sensors that are mounted on flexible pads in accordance with an embodiment of the present invention. 
         FIG. 20  is a bottom view of a touch pad showing how the touch pad may be mounted to an electronic device housing structure using spring structures in accordance with an embodiment of the present invention. 
         FIG. 21  is a diagram of an illustrative touch pad showing circuitry that may be used in gathering and processing touch pad signals and controlling touch pad movement in response to the touch pad signals in accordance with an embodiment of the present invention. 
         FIG. 22  is a graph of an illustrative force sensor output signal plotted as a function of time showing how thresholds may be used in processing the force sensor signal to detect button actuation events such as press and release events in accordance with an embodiment of the present invention. 
         FIG. 23  is a graph showing how signals from each of four sensors in a touch pad may be combined to form an average force signal in accordance with an embodiment of the present invention. 
         FIG. 24  is a graph of an illustrative press signal that may be generated when a press event is detected by processing force signals from force sensors in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 25  is a graph of an illustrative release signal that may be generated when a release event is detected by processing force signals from force sensors in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 26  is a graph of an illustrative press-release pulse that may be generated in response to detecting press and release events by processing force signals from force sensors in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 27  is a graph of a curved symmetrical actuator drive signal having substantially equal rise and fall times that may be used to provide tactile feedback in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 28  is a graph of a symmetrical triangular actuator drive signal having substantially equal rise and fall times that may be used to provide tactile feedback in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 29  is a graph of an asymmetrical actuator drive signal with a rise time that is shorter and faster than its fall time that may be used to provide tactile feedback in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 30  is a graph of an asymmetrical actuator drive signal with a fall time that is shorter and faster than its rise time that may be used to provide tactile feedback in a touch pad in accordance with an embodiment of the present invention. 
         FIG. 31  shows how force signals may be processed to generate press and release event signal when no touch sensor gesturing activity is present in accordance with the present invention. 
         FIG. 32  shows how the generation of press and release event signals in response to force signals may be inhibited when touch sensor gesturing activity is present in accordance with the present invention. 
         FIG. 33  is a diagram showing how touch sensor data may be processed, showing how force sensors may produce raw force output signals that are processed in accordance with force signal processing settings, and showing how resulting press and release event data may be used to produce actuator drive signals based on driver settings in accordance with an embodiment in the present invention. 
         FIG. 34  is a flow chart of illustrative steps involved in setting up and operating a touch pad in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 35  is a simplified schematic diagram of an illustrative computing system that may include a touch sensitive input-output device such as a touch pad that may have force sensors and an actuator for providing feedback in accordance with an embodiment of the present invention. 
         FIG. 36  is a schematic diagram of an illustrative computing system that may include a touch sensitive input-output device such as a touch pad that may have force sensors and an actuator for providing feedback and that may incorporate display structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with touch sensitive user input devices. The touch sensitive user input devices may include touch screens or, more typically touch pads. Touch pads, which are sometimes referred to as track pads, are often used in electronic devices such as portable computers. Touch pads may also be implemented as stand-alone devices. For example, a touch pad may be provided with a universal serial bus (USB) cable that allows the touch pad to be plugged into a USB port on a computer. Touch pads may also be used in industrial and commercial equipment, in computer mice, in keyboards, in game machines, etc. For clarity, the use of touch pads in portable computers (i.e., as portable computer track pads) is sometimes described herein as an example. This is, however, merely illustrative. Touch pads and other touch sensitive input devices may be implemented as part of any suitable electronic equipment. 
     A touch pad may include force sensor and touch sensor circuitry. Tactile feedback may be provided by using an actuator that can impart movement to the touch pad. 
     A touch sensor for the touch pad may be implemented using resistive touch technology, surface acoustic wave technology, capacitive technology, light detectors (e.g., an array of light sensors for a shadow-based sensor that detects position by measuring ambient-light shadows produced by external objects), or other suitable touch sensor arrangements. The use of capacitive touch sensor technologies is sometimes described herein as an example. Unlike touch technologies that require forceful direct contact to register a touch event, capacitive touch sensors can detect touch events even when little or no direct pressure is applied to the surface of the touch sensor. This is because capacitive touch sensors measure changes to capacitance that arise from the presence of user&#39;s finger or other external object in close proximity to the surface of the sensor. 
     The touch sensor capabilities of the touch pad allow the user to provide touch input. A user may, for example, position a fingertip or stylus at a desired location on the surface of the touch pad. By controlling the location at which the touch sensor is touched, the user may control the position of an on-screen cursor or may otherwise interact with the electronic device. If desired, a gesture-based control arrangement may be implemented in which movement of one or more touch locations relative to the screen can be converted into a command. As an example, a swipe of a particular number of fingers across the surface of the touch pad may be interpreted as a command to advance through a list of items or a command to scroll displayed material on a computer screen. Single-tap and multiple-tap commands may also be processed using the touch sensor functions of the touch pad. 
     The force sensor capabilities of the touch pad allow the user to perform button-type activities. In a conventional touch pad with an integral button, the button portion of the touch pad is actuated by pressing firmly downwards near the front edge of the touch pad. This causes the touch pad to pivot downward to actuate a switch that is located under the front edge of the touch pad and produces an audible clicking sound. 
     When force sensors are included in a touch pad, it is not necessary to allow the touch pad to pivot in this way. Rather, force signals from one or more of the force sensors may be used to detect when a user is pressing and depressing the touch pad. The touch pad need not move significantly (i.e., the touch pad may remain essentially motionless and horizontal), so the space that would otherwise be reserved to accommodate pivoting motion can be used to house components. In a typical configuration in which force sensors are implemented using piezoelectric elements, the touch pad may be displaced less than 0.05 mm even under the most forceful button press loads. Force feedback may be used to restore the expected feel of a button press to the user. For example, when it is determined that a user has pressed the touch pad with sufficient force, an actuator may move the touch pad. This may impart a feeling to the user&#39;s finger that resembles conventional touch pad button actuation events. The actuator may produce a clicking sound when moving the touch pad or may be driven so as to produce silent actuation of the touch pad (e.g., by using drive signals with primarily subsonic components). If desired, a clicking sound or other suitable sound may be created by a speaker in accordance with default and/or user-defined settings. 
     In this way, force sensor signals may be used to mimic conventional button functions. For example, force sensor signals can be used to detect when a user presses a touch pad with sufficient force to deflect a conventional pivoting touch pad. In response, the actuator may apply force to the touch pad. 
     If desired, different types of functions or additional functionality may be implemented using a touch pad that includes both force sensors and touch sensors. Functions may also be implemented that depend partly on force signal input values and partly on touch sensor input signal values. As an example, button activity detection operations can be inhibited in the presence of gestures or detection of sufficient force with the force sensors may result in inhibition of the normal response for processing a gesture-based touch sensor command. As another example, a one-handed select-and-drag functionality may be implemented. With this type of arrangement, an on-screen item may be selected and moved by a user by applying sufficient force to the force sensors with a finger while simultaneously moving the finger across the touch sensor. Force sensors may also be used to categorize tap-type commands. Light taps may result in one type of action, medium-strength taps may result in another type of action, and firm taps may result in yet another type of action. Forces that are applied to different portions of the touch pad may result in different types of responses. For example, presses in the left rear corner of a touch pad may result in a different action than presses in the right rear corner. 
     The actions that are taken in response to the processed touch pad signals (force and/or touch sensor signals) may include responses taken by an operating system, responses taken by application software, responses taken by services that are implemented using combinations of software and hardware, responses in device hardware, other actions, and combinations of these responses. 
     An example of a response that may be affected by force and/or touch signals is a tactile feedback function. Tactile feedback, which is also sometimes referred to as touch feedback, force feedback, or haptic feedback, involves the production of touch pad movement in response to certain detected actions. For example, tactile feedback may be generated when the force sensors in the touch pad detect a finger press that has exceeded a given threshold. Hardware and, if desired, software such as firmware, operating system code, and application code, may be used in implementing force feedback arrangements. If desired, a tactile response may be generated independent of a particular button press or touch event. For example, a touch pad with force-feedback capabilities may be vibrated when an email is received or when a scheduled event has occurred. These types of use of touch pad tactile functions are sometimes referred to herein as force-feedback functions, tactile feedback functions, haptic feedback, etc. 
     A touch pad that includes touch sensors, force sensors, and/or force feedback capabilities may be implemented in a portable electronic device, an accessory, a cellular telephone, an embedded system, or any other suitable electronic equipment. For clarity, arrangements in which touch pads such as these are included in portable electronic devices are sometimes described herein as an example. 
     An illustrative portable device such as a portable computer that may include a touch pad is shown in  FIG. 1 . As shown in  FIG. 1 , device  10  may be a portable computer having a housing such as housing  12 . Housing  12  may have an upper portion such as upper housing  12 A, which is sometimes referred to as a lid or cover. Housing  12  may also have a lower portion such as lower housing  12 B, which is sometimes referred to as the housing base or main unit. Housing portions  12 A and  12 B may be pivotably attached to each other using a hinge structure such as hinge  16  (sometimes referred to as a clutch barrel hinge). Display  14  may be mounted in upper housing  12 A. Other components such as keyboard  18  and touch pad  20  may be mounted in lower housing  12 B. 
     Touch pad  20  may include a planar touch pad member containing a touch sensor. The touch sensor may be formed from an array of touch sensor structures (e.g., touch sensor capacitive electrodes). In general, the touch sensor structures in touch pad  20  may be implemented using any suitable touch-sensitive technology. Examples of touch sensors that may be used to provide touch pad  20  with touch sensing capabilities include capacitive touch sensors, touch sensors based on resistive sensing, surface acoustic wave touch sensors, and optical touch sensors. Illustrative configurations for touch pad  20  that are based on capacitive touch sensors are sometimes described herein as an example. This is, however, merely illustrative. Any suitable touch technology may be used to provide touch pad  20  with the ability to sense the position of a user&#39;s finger, stylus, or other external object. 
     The user&#39;s touch may be sensed when the external object is in direct contact with the surface of the touch pad or may be sensed when the external object is in close proximity to the surface (e.g., when a capacitive touch sensor detects that a user&#39;s finger of other object is within a few millimeters of the touch sensor surface). Events in which the touch sensor portion of the touch pad is controlled by the position of an external object are typically referred to as touch events, regardless of whether a touch signal was generated by direct contact between the external object and the touch pad or whether the touch signal was generated in response to a close proximity between the external object and the touch pad. 
     As shown in  FIG. 1 , touch pad  20  may have lateral dimensions XX and YY. Lateral dimension XX, which is sometimes referred to as the width of the touch pad, may run parallel to the X-axis in X-Y-Z coordinate system  22 . Lateral dimension YY, which is sometimes referred to as the length of the touch pad, may run parallel to the Y-axis in X-Y-Z coordinate system  22 . The structures that make up touch pad  20  also have a dimension that runs parallel to the Z-axis in X-Y-Z coordinate system  22 . This dimension is sometimes referred to as the vertical dimension or out-of-plane dimension of the touch pad. As shown in  FIG. 1 , the Z-axis extends perpendicular to the X-Y plane that contains the X-axis and Y-axis (i.e., the Z-axis is perpendicular to the plane of the exposed planar surface of touch pad  20 ). To ensure that the thickness of device  10  is minimized, it may be helpful to minimize the thickness of the structures associated with touch pad  20 . 
     The location of the user&#39;s finger(s) or other external object(s) in the X-Y plane of touch pad  20  can be sensed using the touch sensor of touch pad  20 . Downwards and upwards motion along the Z-axis can be detected using force sensors. As shown in  FIG. 2 , touch sensor  20  may have a planar touch pad member  24  (sometimes referred to as a track pad member). Touch pad member  24  may include a touch sensor. The touch sensor can be used to measure the position of external objects such as finger  26  with respect to the X and Y lateral dimensions of planar touch pad member  24 . As indicated by dots  32 , there may be more than external object (i.e., more than one finger) touching touch pad member  24  (e.g., when a user is making a multi-touch gesture command). Arrangements in which a single object is touching touch pad member  24  are sometimes described herein as an example. This is, however, merely illustrative. One object, two objects, three objects, or more than three objects may simultaneously contact touch pad member  24  if desired. 
     In addition to touching touch pad member  24  at one or more locations, a user may generate button actuation events. Button actuation events involve press events in which a user presses downwards in direction  28  along the Z axis (see, e.g., coordinate system  22 ). Button actuation events also involve release events. In a release event, the user reduces the amount of downwards force that is being applied to touch pad member  24  and stops moving finger  26  in direction  28  (e.g., by lifting finger  26  upwards in direction  30 ). 
     Button actuation actions, which are sometimes referred to as force application events, can be sensed using force sensors  34 . Force sensors  34  are generally responsive to forces that are applied vertically (along the Z-axis). There may be one force sensor  34  in touch pad  20 , two force sensors  34  in touch pad  20 , three force sensors  34  in touch pad  20 , or four or more force sensors  34  in touch pad  20 . Force sensors may be placed under the four corners of a rectangular planar touch pad structure such as member  24  as shown in  FIG. 2  (as an example). In configurations with two sensors, sensors can be positioned at opposing edges of member  24 . In configurations with three sensors, the sensors can be distributed so as to form a tripod-type configuration. If only a single sensor is used, the sensor may be located beneath the center of touch pad member  24  or along an edge of touch pad member  24  (e.g., the leading edge). 
     An advantage of placing force sensors  34  at all four corners of touch pad member  24  is that this allows force signals from multiple sensors to be gathered and processed in parallel. The force sensor signals may be averaged, may be processed to help confirm the location of the user&#39;s finger on member  24 , or may be processed to determine what type of action should be taken by device  10 . 
     Button actuation activity or other activity (e.g., certain touch events) may result in force feedback. For example, when the user presses downwards on member  24  in direction  28 , force sensors  34  may compress slightly and may detect the resulting force on member  24 . If a sufficient downwards force is detected, actuator  36  may be used to impart movement (tactile feedback) to member  24 . With the illustrative arrangement shown in  FIG. 2 , actuator  36  is coupled to planar touch pad member  24  by laterally extending arm  40 . Arm  40  may be, for example, a strip of metal or other structure that is rigidly connected between the output of actuator  36  and touch pad member  24 . 
     When actuator  36  is driven by a control signal, actuator  36  drives arm  40  toward and/or away from planar touch pad member  24  (e.g., in lateral directions  38  parallel to the X-axis in the  FIG. 2  example). The movement imparted by actuator  36  is sometimes referred to as tactile feedback, because this type of movement may be provided in response to a button actuation event. Users tend to expect that button actuation events will result in a clicking feel and sound. By driving actuator  36  appropriately, vibrations or other movement in touch pad  24  may produce a desired tactile experience for the user (e.g., in the tips of fingers  26 ). For example, it may feel to the user as if pad  24  moved downwards and engaged a conventional mechanical switch, when in actuality, force sensors  34  allowed relatively little vertical movement of member  24 , because touch pad member  24  is mounted in a substantially fixed location within housing  12 B. If desired, actuator  36  can impart force to bar  40  and therefore touch pad member  24  in response to other criteria (e.g., when certain software conditions arise, when the user makes certain gestures that are sensed using the touch sensor portion of touch pad  20 , etc.). 
     Touch pad  20  may be formed from a layered stack of structures. For example, touch pad member  24  may include a printed circuit board or other substrate on which an array of touch sensor electrodes are formed. The array of electrodes may be substantially equal in size to the size of the touch pad member, so that the touch pad member and the array extend across all of the active surface of the touch pad. 
     Stiffeners, smooth glass cover layers, and layers of ink and adhesive may also be incorporated into touch pad member  24 . If desired, size and weight may be minimized by implementing touch pad  20  with fewer layers. For example, touch pad  20  may be implemented using a glass or ceramic layer with integrally formed capacitive electrodes and no stiffener, provided that touch pad  20  is still rigid. The stiffness of touch pad member  24  ensures that button actuation activity by a user will be detectable by force sensors  34 , regardless of the location at which the user presses the surface of the touch pad member. Use of a rigid touch pad member in touch pad  20  also helps ensure that a single actuator (or other suitable number of actuators) is able to effectively generate tactile feedback over the entire surface of the touch pad member (i.e., global actuator-induced motion). If the ceramic, glass, plastic, or other layers of touch pad member  24  that are used to form the contact surface and touch sensor array for touch pad member  24  are flexible, a stainless steel stiffener or other suitable stiffening structure may be incorporated into touch pad member  24 . Touch pad member  24  may also be stiffened by using sufficiently thick layers of glass, ceramic, plastic, or composite materials without using an extra stainless steel stiffening layer (e.g., by forming some of the layers of touch pad member  24  from glass, ceramic, plastic, or composite material that is 1 mm thick or more, 2 mm thick or more, 3 mm thick or more, or 4 mm thick or more (as examples). A rectangular shape is typically used for touch pad member  24 , because this corresponds to the rectangular shape of display  14 . Other shapes may, however, be used if desired. These are merely illustrative examples. Any suitable touch pad structures may be used in forming touch pad  20  if desired. 
     An exploded perspective view of an illustrative set of structures that may be used in touch pad  20  is shown in  FIG. 3 . As shown in  FIG. 3 , touch pad  20  may contain rectangular planar touch pad member  24 . Planar touch pad member  24  may be mounted to housing structure  12 B. Housing structure  12 B may be formed by part of a housing wall (e.g., a lower wall in base unit  12 B of  FIG. 1 ), by an internal housing frame structure or support, by other suitable support structures, or by combinations of these structures. 
     Force sensors  34  may be located at each of the four corners of touch pad member  24 . If desired, mounting pads such as mounting pads  42  may be interposed between force sensors  34  and housing structures  12 B. Pads  42  may be formed from a flexible material such as gel or foam. Gel for pads  42  may be formed from a material such as silicone. When pads such as silicone gel pads are placed between sensors  34  and housing  12 B, touch pad member  24  is allowed to move slightly (e.g., several thousand microns or less, several hundreds of microns or less, etc.) in the X and Y dimension (e.g., laterally, parallel to the planar inner surface of housing  12 B) in response to the application of lateral force (in-plane force) by actuator  36 . If touch pad member  24  were mounted too rigidly to housing  12 B, touch pad member  24  might not exhibit a desired amount of tactile feedback (i.e., vibrations in member  24  might be overly damped). Pads  42  may be connected to housing  12 B using adhesive. Force sensors  34  may be connected to pads  42  by adhesive. Adhesive may also be used to connect force sensors  34  to planar touch pad member  24 . Although the presence of gel pads  42  allows microscopic lateral movement of rigid touch pad member  24 , touch pad member  24  remains at a substantially fixed location within housing  12 B (i.e., there is no discernable visual movement to a user). Unlike conventional arrangements in which pivoting motion is required to actuate associated switches, no hinges or pivoting flexures are attached to touch pad member  24  and touch pad member  24  does not pivot or move substantially during button actuation and tactile feedback. Moreover, because touch pad member  24  is generally implemented as a rigid structure, touch pad member  24  does not flex. Rather, touch pad member  24  operates as a single rigid unit during button actuation and tactile feedback events. 
     Uppermost layer  56  of member  24  may be formed from a smooth layer of glass or other suitable materials (e.g., plastic, ceramic, etc.). In capacitive touch sensor arrangements, layer  56  may be formed from dielectric to prevent electromagnetically blocking underlying capacitive electrodes. 
     The material from which layer  56  is formed may be transparent (e.g., clear glass). In this type of situation, it may be desirable to provide the lower surface of layer  56  with an opaque layer of paint or ink. For example, a layer of silver ink or other cosmetic coating may be placed below layer  56  (see, e.g., ink layer  54 ). Layer  56  may also be formed from an opaque substance (e.g., dark glass or ceramic). Regardless of whether layer  56  is formed from an opaque substance or whether layer  56  is opaque by virtue of an underlying layer of opaque material such as opaque ink, the structures of touch pad member  24  such as layer  56  are typically sufficiently opaque to block lower-layer structures from view from the exterior of device  10 . By forming the uppermost layer or layers of touch pad  24  from opaque structures, unsightly structures in the lower layers of touch pad member  24  may be blocked from view. Because of the potential for enhancing the aesthetics of touch pad  20  by using one or more layers of opaque materials, it is generally desirable to form touch pad member  24  from structures that cause touch pad member  24  to be opaque (i.e., from a stack-up that does not permit light to be transmitted through touch pad member  24 ). 
     When it is desired to use touch pad  20  as part of a touch screen (e.g., when forming a stack-up of layers to form a liquid crystal display touch screen, an electronic ink display touch screen, or other touch screens), there is preferably no opaque ink present on layer  56 . Rather, layer  56  may be formed from a layer of display cover glass or other transparent display structure. Although stand-alone touch pads are sometimes described herein as an example, the touch sensor, force sensor, and actuator mechanism of touch pad  20  may be used in a touch screen display or any other type of component. Stand-along computer track pads are merely described herein as an example. 
     As shown in  FIG. 3 , a layer of adhesive such as pressure sensitive adhesive layer  52  may be used to attach layers  56  and  54  to touch sensor array  50 . Touch sensor array  50  may be formed from an array of conductive capacitor electrodes (e.g., to form an X-Y capacitive touch sensor). These electrodes, which may be formed from metal, transparent conductive materials such as indium tin oxide, or other conductive materials may be formed on the underside of layer  56  or, as shown in  FIG. 3 , may be formed on one or both sides of a printed circuit board substrate to form sensor array  50 . The printed circuit board substrate may be rigid or flexible. Rigid circuit boards in device  10  may be formed from materials such as fiberglass-filled epoxy (e.g., FR4). Flexible printed circuit boards (“flex circuits”) may be formed from conductive traces on flexible sheets of polymers or other dielectrics (e.g., polyimide). 
     A layer of adhesive such as pressure sensitive adhesive layer  48  may be used to attach touch sensor array  50  to stiffener  46 . Stiffener  46  may be formed form a stiff material such as metal (e.g., stainless steel, aluminum, titanium, etc.). Materials such as glass, ceramic, carbon-fiber composites, and plastic may also be used. To reduce weight, portions of stiffener  46  may be removed (e.g., to form holes  58 . 
     Force sensors  34  may be formed from piezoelectric devices, structures that exhibit changes in resistance, capacitance, or inductance as force is applied, or any other suitable force sensing structures. 
     As shown in  FIG. 4 , force sensor  34  may be formed from a structure that bends such as bendable member  60  (e.g., a strain gauge structure). In this type of force sensor, a Wheatstone bridge circuit or other circuitry may be placed on the surface of member such as member  60  to detect changes in surface resistance and/or bulk resistivity when member  60  is bent. Member  60  may, for example, be formed from a deflectable dielectric on which metal traces  62  have been formed. Traces  62  may include interdigitated fingers  62 A and  62 B. When deflected in direction  64 , member  60  assumes position  66 . This deflection may generate a measurable change in the resistance across traces  62 A and  62 B or other detection circuitry located on the surface of member  60 . This resistance change may serve as an indicator of the amount of force that is being applied to force sensor  34 . 
     Each force sensor  34  may also be implemented using a structure in which a solid is compressed or in which the distance between planar surfaces is altered as a function of applied force. Consider, as an example, an arrangement of the type shown in  FIG. 5 . In the  FIG. 5  example, force sensor  34  may have an upper surface  66 . The when force is applied in downwards direction  28  to sensor  34 , the upper surface of sensor  34  may be moved to position  68 . In this position, there is a measurable change in the properties of sensor  34 . For example, sensor  34  may be formed from a piezoelectric material that generates a voltage that is proportional to the amount of compression in sensor  34 . As another example, sensor  34  may be formed from a foam or other compressible material that has a different resistance when compressed than when uncompressed. The material for sensor  34  may be, for example, a polymer-metal composite or a polymer filled with nanoparticles (e.g., quantum tunneling composite materials of the type available from Peratech Limited of Richmond, North Yorkshire, United Kingdom). Force sensors may also be used that exhibit changes in inductance, changes in magnetism, or other measurable force-dependent properties. 
     As shown by force sensor  34  in the example of  FIGS. 6 and 7 , force sensor  34  may have a structure such as member  70  that has compressible protrusions  74 . In the position shown in  FIG. 6 , member  70  has not been compressed relative to member  72 , so protrusions  74  are not compressed. When a downward force is applied to member  70 , protrusions  74  may compress and deform, as shown in  FIG. 7 . Member  70  may be formed from a resistive foam and member  72  may be formed from a conductor (as an example). In the compressed state shown in  FIG. 7 , the resistance between member  70  and  72  will be less than in the uncompressed state shown in  FIG. 6 . As a result, measurement of the resistance between members  70  and  72  will reflect the amount of force that has been applied to member  70 . 
     Force sensor  34  may have electrodes. For example, force sensor  34  may have upper capacitor electrode  76  and lower capacitor electrode  78 , as shown in  FIG. 8 . Capacitor sensor circuitry  80  may be used to determine the distance between electrodes  76  and  78  by measuring the capacitance across electrodes  76  and  78 . When a force is applied that moves electrode  76  downwards in direction  82 , the capacitance (and therefore capacitance output signal OUT) will rise, indicating the presence of the force. Foam, other elastomeric substances, or other resilient structures may be placed between electrodes  76  and  78 , so the magnitude of the rise in capacitance reflects the amount of applied force. 
       FIG. 9  shows how force sensor  34  may be based on a variable resistor such as resistor  84  that exhibits changes in resistance in response to changes in applied force. Variable resistor  84  may be formed using structures of the types described in connection with  FIGS. 4, 5, 6, and 7  (as examples). Resistance measurement circuitry  86  may be used to convert force-based resistance changes in to corresponding force sensor output signals (output signal OUT). 
     As these examples demonstrate, force sensors  34  may be formed from any structures that produce an output signal that is responsive to applied force. In a typical scenario, the amount of output signal that is produced by each force sensor  34  will be linearly or non-linearly proportional to the amount of applied force (i.e., sensors  34  will be analog force sensors). If desired, dome switches or other binary switches may be used in place of analog sensors. In this type of arrangement, the state of the dome switch (open or closed) may be used to determine whether the applied force is above or below a given threshold (i.e., the dome switch&#39;s activation threshold). 
       FIG. 10  is a cross-sectional side view of an illustrative actuator such as actuator  36  of  FIG. 1 . Actuator  36  may be a solenoid having a barrel  94  that contains wraps of wire  96 . The wire in barrel  94  may be connected to terminals  88  and  90 . When a current is applied to terminals  88  and  90 , a magnetic field is formed that draws magnetic plunger  92  into the interior of barrel  94 . By modulating the current that flows into terminals  88  and  90 , plunger  92  may be moved back and forth along the longitudinal axis of barrel  94  in directions  38 . 
     Plunger  92  may have portions that form coupling member  40  of  FIG. 2  or may be connected to a member such as coupling member  40  of  FIG. 2 . If desired, actuator  36  may be formed from a linear motor, a rotating motor, or other electromagnetic actuator structure. Actuator  36  may also be formed from piezoelectric materials and other structures that are capable of producing movement in response to an applied electrical signal. 
     As shown in the top view of  FIG. 11 , actuator  36  may be located in the vicinity of touch pad member  24 . Coupling member  40  may be directly connected to the movable structures of actuator  36  (e.g., plunger  92  of solenoid  36  in  FIG. 10 ) and may be directly connected to the edge of touch pad member  24  (e.g., to one or more of the layers shown in  FIG. 3 ). The length of member  40  may be less than the largest dimension of solenoid  36  (as an example). 
     It is not necessary to directly connect member  40  to both actuator  36  and touch pad  24 . For example, there may be a gap such as gap  98  between member  40  and touch pad member  24 , as shown in  FIG. 12 . Gaps may also be formed in the vicinity of actuator  36 . 
       FIG. 13  shows how actuator  36  may be mounted within device  10  at a location that is somewhat remote from touch pad member  24 . The length of member  40  may be, for example, 2-5 mm, 5-10 mm, 2-20 mm, 10-30 mm, or more than 30 mm. At larger lengths, the length of member  40  (and therefore the distance between actuator  36  and touch pad member  24 ) may be 1, 2, 3, or more than 3 times larger than the largest dimension of actuator  36 . 
     As shown in the example of  FIG. 14 , member  40  need not be straight. Member  40  may, for example, include one or more bends such as bends  100  and  102 . 
       FIG. 15  shows how actuator  36  and touch pad member  24  may be connected by a mechanical linkage (linkage  40 ). The structures of linkage  40  may allow the amount of force that is applied by actuator  36  to be increased or decreased through the use of mechanical advantage. The use of linkages such as linkage structures  40  may also allow actuator  36  to be located in positions within device  10  that might otherwise not be feasible (e.g., due to the presence of blocking structures, etc.). 
     During operation, actuator  36  may move member  40 C in direction  110 . Members  40 C and  40 B may be connected at pivot point  104 . Member  40 B may pivot relative to the device housing about pivot point  106 . When actuator  36  moves member  40 C in direction  110 , member  40 B may be forced to rotate clockwise (direction  112 ) about pivot point  106 . This forces member  40 A, which is connected to member  40 B at pivot  108 , to move against touch pad member  24  in direction  114 . 
     More than one actuator may be used to impart movement to touch pad  24 .  FIG. 16  shows an illustrative configuration in which a pair of actuators are coupled to touch pad member  24 . Left-hand actuator  36 - 1  is connected to the left edge of touch pad member  24  using coupling member  40 - 1 , whereas right-hand actuator  36 - 2  is connected to the right edge of touch pad member  24  using coupling member  40 - 2 . Actuators  36 - 1  and  36 - 2  may be driven by signals that are 180° out-of-phase with respect to each other (as an example). In configurations in which touch pad member  24  is completely rigid, the use of multiple actuators may help efficiently impart global movement to all of the structures in touch pad member  24  (i.e., the actuators may generate motion in touch pad member  24  that is substantially uniform throughout the touch pad member). Lateral in-plane actuation may be used to help enhance energy transfer efficiency between the actuators and the touch pad member. If desired, one or more actuators may be used to impart vertical movement to touch pad member  24 . This type of actuation arrangement may be advantageous when satisfying design constraints. 
     If desired, touch pad member  24  may be implemented using one or more flexible structures (e.g., thin sheets of glass or metal, plastic layers that exhibit flexibility, etc.) In both flexible and somewhat rigid embodiments, two or more actuators may be used to selectively impart movement to different areas of touch pad member  24 . For example, if there are four actuators coupled to touch pad member  24 , one actuator may be driven independently of the others in order to impart movement to the upper left corner of the touch pad (as an example). If numerous actuators are used, more focused tactile feedback may be provided. 
     Multiple actuator configurations such as these may be used to provide tactile confirmation to a user when a particular portion of a touch pad surface has been depressed without interfering with other fingers or objects that are in contact with the touch pad at other locations. For example, touch pad member  24  may be pressed in different locations to perform different commands. If a user presses one location, that location may be moved by one or more associated actuators. If the user presses a different location, different actuators may be used to provide force feedback in the vicinity of that location. Global feedback arrangements may also be used in which different actuator drive signals are used in response to detection of button presses in different areas. 
     Arrangements in which actuators are used to provide different degrees of tactile feedback in different locations are sometimes referred to as variable actuation schemes. Variable actuation schemes may be used to provide a user of touch pad  20  with informative tactile feedback based on force sensor signals and/or touch sensor array signals. If desired, variable actuation schemes may be used in combination with other actuation schemes. For example, global actuation schemes of the type involving a single actuator that imparts global movement to all of touch pad member  24  may be used during some activities (e.g., when certain software applications are running), whereas variable actuation approaches may be used during other activities (e.g., when running other applications). Global movement may be imparted laterally, whereas localized movement may be imparted using vertically oriented sensors, different collections of one or more sensors, etc. 
       FIG. 17  is a cross-sectional side view of an illustrative actuation setup that may be used to impart movement to touch pad member  24 . In the example of  FIG. 17 , actuator  36  is oriented so that plunger  116  is forced upwards in direction  118  when a drive signal is applied to actuator  36 . This pulls portion  120  of coupling member  40  upwards in direction  118 . Pivot  112  may be coupled to the device housing, so that movement of portion  120  forces edge  128  of member  40  to bear against the corresponding left-hand edge of touch pad member  24  in direction  126 . 
     Arrangements of the type shown in  FIG. 17  may be used when it is desired to place actuator  36  at a vertical position that is different than the vertical position of touch pad member  24  or when desired to satisfy layout constraints. 
     Touch pad member  24  may be driven by actuator  36  in any suitable direction (laterally, vertically, at an angle, using both lateral and vertical displacement schemes simultaneously, etc.). 
     Lateral actuation of touch pad member  24  (i.e., actuation that results in in-plane movement of member  24 ) may be advantageous, because touch pad member  24  is stiffest when force is applied laterally to one of its edges (e.g., directly to a vertical edge of a stiffening member or to a coupling structure located immediately adjacent to the edge of the stiffening member). When touch pad member  24  is rectangular, touch pad member  24  may be most resistant to undesired flexing when biased on one of its narrower ends, as shown in the examples of  FIGS. 11-16 . In this type of configuration, less energy is wasted during actuation. Lateral actuation may also be superior to other types of actuation (e.g., actuation involving vertical displacement of a portion of touch pad member  24  parallel to the Z-axis, which could lead to undesired irregular “drum-like” vibration modes). Lateral actuation may create less noise than vertical actuation and may therefore be more efficient than vertical actuation, particularly when mounting schemes are used for touch pad member  24  that allow for lateral movement of touch pad member  24  relative to housing  12 B (e.g., when gel pads  42  of  FIG. 3  are used). Because noise can be minimized, tactile feedback may be provided silently if desired. 
       FIG. 18  is a cross-sectional side view of an illustrative configuration in which bearings are used to help facilitate lateral movement of touch pad member  24 . As shown in  FIG. 18 , actuator  36  may be mounted to upper wall  130  of housing  12 B. Member  40  may be connected between touch pad  24  and actuator  36 , so that actuator  36  can drive touch pad member  24  laterally in directions  38 . Silicone bumpers  132 , which may be supported by lower housing wall  138  or other suitable support structures, may be used to help hold touch pad member  24 . Magnetic structures  134  and mating magnetic structures  136  may exhibit magnetic attraction to each other, creating a downwards force in direction  146 . Magnetic structures  134  and  136  may both be magnets or one of structures  134  and  136  may be an iron bar or other ferromagnetic structure. 
     Bearing structures may support touch pad  24 . For example, bearing structures may be formed from bearing mounts  140  and bearings  142 . As touch pad  24  is moved by actuator  36  in directions  38 , balls  142  roll along lower surface  144  of touch pad member  24 . By facilitating lateral movement of touch pad member  24  in this way, the amount of energy that is required to impart tactile feedback to touch pad member  24  using actuator  36  may be reduced (i.e., actuation efficiency may be enhanced). 
     The side view of  FIG. 19  shows how force sensors  34  may be mounted on gel pads  42  or other mounting structures that allow touch pad member  24  to move slightly in lateral directions  38  when laterally actuated using actuator  36 . Pads  42  may move somewhat when force is imparted to touch pad member  24 . Because touch pad member  24  is not rigidly attached to housing  12 B, the energy of actuator  36  may be efficiently imparted to touch pad member  24 . 
       FIG. 20  is a bottom view of touch pad member  24  showing how touch pad member  24  may be mounted within a rectangular opening in upper housing wall  130  using springs  148 . Springs  148  may be metal springs that are stamped or cut from a piece of sheet metal or may be formed in an integral fashion by cutting springs  148  directly into a portion of upper housing wall  130 . As with flexible pads  42  of  FIG. 19 , springs  148  of  FIG. 20  may allow touch pad member  24  to move laterally in directions  38  when actuated by actuator  36 . 
     A top view of an illustrative electrode array for a capacitive touch sensor in touch pad  20  is shown in  FIG. 21 . As shown in the example of  FIG. 21 , touch pad array  150  may be formed from horizontal electrodes  154  and vertical electrodes  152  on substrate  51 . Substrate  51  may be formed from rigid or flexible printed circuit board material or other suitable substrates. Path  156  may be used to convey electrode signals from electrodes  152  and  154  to touch sensor processing circuitry  158 . Touch sensor processing circuitry  158  can convert capacitance changes that are detected using electrodes  152  and  154  into position data (e.g., to locate the position of an external object such as a user&#39;s finger on touch pad member  24 ). Force sensors  34  may supply force signals to force sensor processing circuitry  162  via path  164 . Force sensor processing circuitry  162  may process raw sensor signals to determine the amount of force that is present on each of sensors  34  (e.g., due to forces applied to the touch pad by the user). Driver circuitry  166  (e.g., an audio amplifier or other output driver) may be used to supply drive signals to actuator  36 . When driven in this way, actuator  36  may impart movement to the touch pad via coupling structures such as structure  40 . 
     Circuitry  162  and  158  may form part of storage and processing circuitry  160 . Storage and processing circuitry  160  may include discrete components and integrated circuits mounted on one or more printed circuit boards in device  10 . Storage in storage and processing circuitry  160  may be formed by volatile and nonvolatile memory circuits. Hard disk drives and other media may also be used to store information in device  10  if desired. Processing circuitry in storage and processing circuitry  160  may be implemented using application-specific integrated circuits (ASICs), digital signal processing circuits, microcontrollers, microprocessors, and other circuits. Software such as application code, operating system instructions, and firmware may be used in implementing functions for operating touch pad  20 . For example, software may be used to implement control algorithms that determine when actuator  36  should apply force to touch pad member  24 . Hardware such as circuitry  162 , driver circuitry  166 , and circuitry  158  may be used in gathering and processing sensor signals and in applying appropriate drive signals to actuator  36 . 
     In a typical scenario, control functions may be implemented using a combination of hardware and software. For example, signal processing algorithms for gathering force and sensor data may use the hardware functions of the touch and force sensors and the hardware functions of associated processing circuits such as processing circuits  162  and  158 . Once raw sensor signals have been processed, appropriate actions may be taken (e.g., by applying a drive signal to actuator  166  using hardware such as driver circuit  166 ). The control algorithms that are used in determining which actions to take in response to detection of particular patterns of sensor data may be hardwired (e.g., using a dedicated circuit), may use software, etc. 
     An illustrative force signal that may be produced when a user presses downwards on the planar exterior surface of the touch pad is shown in  FIG. 22 . As shown in  FIG. 22 , force F may initially rise upwards as a function of time (e.g., while the user is exerting increasing amounts of downwards force on the touch pad). When the user lifts the finger from the surface of the touch pad, the amount of force that is measured by the force sensor decreases. 
     Signal processing algorithms that are used in processing force signals such as force signal F of  FIG. 22  may include frequency-dependent filtering algorithms (e.g., low-pass filters, band-pass filters, and high-pass filters), time-based algorithms, algorithms that exhibit hysteresis (e.g., for implementing debounce functionality) and algorithms that apply force magnitude thresholds. As an example, storage and processing circuitry  160  ( FIG. 21 ) may ignore all force signals with a magnitude of less than force threshold FT 1  (e.g., a noise threshold). Force signals that rise above and/or that fall below other thresholds (e.g., force thresholds FT 2  and FT 3 ) may be categorized as corresponding to button press events and button release events. 
     The graph of  FIG. 23  illustrates how storage and processing circuitry  160  may process signals from multiple force sensors  34 . In the  FIG. 23  example, touch pad  20  has four force sensors  34  that produce respective force signals FFL (from the front left sensor), FFR (from the front right sensor), FBL from the (back left sensor), and FBR (from the back right sensor. These signals may be processed to determine the location of the user&#39;s finger or to extract other information on the nature of the user&#39;s force activity. With one suitable arrangement, the four independent force signals are combined (e.g., digitally added and/or averaged) to produce combined force signal FAVG. The use of combining techniques such as this may help to reduce noise and improve force sensor accuracy. 
     By processing analog force sensors of the type shown in  FIGS. 22 and 23 , storage and processing circuitry  160  may produce corresponding digital signals. For example, storage and processing circuitry  160  may produce a digital PRESS signal of the type shown in  FIG. 24  to indicate that a user has completed a press event and a may produce a digital RELEASE signal of the type shown in  FIG. 25  to indicate that a user has completed a release event. The duration of the PRESS signal (t 2 −t 1 ) and the RELEASE signal (t 4 −t 3 ) may be fixed or PRESS and RELEASE may be continuously asserted until cleared (as examples).  FIG. 26  shows how press and release events may be represented by leading and falling edges in a combined PRESS/RELEASE signal. 
     Press and release events may be identified by applying thresholds to the force signals from the force sensors. As one example, a user button press (assertion of PRESS) may be identified when the average force sensor signal FAVG exceeds a default or user-defined threshold value. 
     The user may adjust the settings that are used in processing the touch and force sensor signals. For example, the user may adjust sensitivity settings that affect timing and magnitude threshold values and other filtering parameters. The user may also adjust the type of drive signal that is supplied to actuator  36 . The shape and magnitude of the actuator signal will generally influence the amount of force that is applied by the actuator to the touch pad and the type of motion that is imparted. 
       FIG. 27  shows an illustrative smooth (curved) and symmetric actuator drive signal that may be used in driving actuator  36 .  FIG. 28  shows a symmetrical, but more sharply shaped drive signal that may be used. The examples of  FIGS. 29 and 30  show how the actuator may be driven using asymmetric signals. Signals with short rise times (e.g., signals of the type shown in  FIG. 29 ) tend to produce tactile feedback of a different quality than signals with short fall times (e.g., signals of the type shown in  FIG. 30 ). Symmetric and asymmetric drive signals may also produce noticeably different results. If desired, drive signals may be used that exhibit primarily subsonic frequency components (e.g., frequencies of less than 20 Hz, less than 15 Hz, etc.), thereby ensuring the possibility of silent operation of the tactile feedback function (e.g., when audible speaker feedback is deactivated). Drive signals may also be provided with multiple peaks (e.g., as a double pulse) or may have other complex waveforms. A user may adjust settings in device  10  to control processing settings and feedback settings to suit the user&#39;s personal requirements. For example, a user may instruct storage and processing circuitry  160  to generate a desired drive shape when a press event is detected and to generate a different desired drive shape when a release event is detected. 
     Force signals and touch sensor signals may be processed together by storage and processing circuitry  160 . For example, force sensor processing and/or force feedback may be inhibited when gesturing activity is detected. This prevents inadvertent button presses from being detected and prevents undesired feedback. 
     Consider, as an example, the situation of  FIG. 31 . In this situation, the user is not moving a finger across the touch sensor (i.e., the user is not making a gesture command). Storage and processing circuitry  160  can monitor the touch sensor signals gathered by the touch sensor portion of touch pad  20  and can conclude that gesturing activity is not present. When a force signal such as force F of the graph on the left-hand side of  FIG. 31  is detected, force sensor processing operations may be performed to detect press and release events. Corresponding PRESS and RELEASE signals may be produced to enable higher-level processing and corresponding actuation of touch pad member  24  by actuator  36 . 
     If, however, the user is in the process of entering gestures using touch pad  20 , the user&#39;s active use of the touch sensor can be detected by storage and processing circuitry  160 . When the user makes gestures, the user&#39;s fingers move across the surface of the touch pad. Occasionally, the user may inadvertently press on the touch pad surface during a gesture. By detecting gesturing activity, the force-feedback functionality of touch pad  20  can be momentarily inhibited. As shown in  FIG. 32 , when force-feedback functions are inhibited, the detection of a force F of the type show in the graph on the left-hand side of  FIG. 32  will not result in generation of any PRESS and RELEASE signals. As a result, no drive signals will be supplied to the driver circuit of actuator  36  and actuator  36  will not produce tactile feedback during gesturing, regardless of how sensitive the force button press feedback function is during normal operation in the absence of gesturing activity. 
     If desired, force feedback can be manually turned off (e.g., if the user is expecting to use the gesture function and does not want to inadvertently generate a button press). Force feedback strength can also be adjusted based on which application is currently running, which user is logged into a multi-user system, the time of day, the presence of other conditions, etc. 
     Sound may be produced in concert with tactile feedback to help inform the user that a button actuation event has occurred (e.g., using a speaker in device  10 ). Default and user-selected sounds may be produced. If desired, the sounds that are produced may be tied to selection of the actuation drive signals. For example if the actuator drive signal has a shape of the type shown in  FIG. 29 , a different sound may be generated than if the actuator drive signal has a shape of the type shown in  FIG. 30  (as an example). 
       FIG. 33  shows how force sensor, touch sensor, and driver settings may be used to adjust the operation of touch pad  20 . As shown in  FIG. 33 , one or more force sensors  34  may generate force data (e.g., data related to how forcefully a user&#39;s finger is pressing downwards on the touch pad). A touch sensor array  168  in pad  20  may generate touch data (e.g., data related to the position of a user&#39;s finger in the X-Y plane of the touch pad). 
     User-defined and default force signal processing settings may be provided to force signal processing circuitry  162 . These signals may include force thresholds, time thresholds, frequency-dependent filter criteria, and other criteria that influence how force data is processed and interpreted by force signal processor  162 . Based on these settings, force signal processing circuitry  162  may produce processed force data signals (e.g., press and release data) from the force data. 
     User-defined and default touch signal processing settings may be provided to touch sensor processing circuitry  158 . These signals may include sensitivity settings, palm-check settings for inhibiting touch response while a user is typing on keyboard  18 , filter settings, and other suitable processing criteria that influence how touch sensor array data is processed and interpreted by touch sensor signal processing circuitry  158 . Based on these settings, touch sensor signal processing circuitry  158  may produce processed touch data signals (e.g., finger location data) from the touch data provided by touch sensor  168 . 
     Drive signal generator  170  may be adjusted using default and user-adjusted driver settings. These settings may include, for example, settings that control the shape and magnitude of the drive control signal that is applied to actuator  36 . Drive signal generator  170 , which may be implemented in dedicated hardware, resources in storage and processing circuitry  160  of  FIG. 21 , or other suitable resources, may supply actuator control signals for actuator  36 . These signals may be driven into actuator  36  using driver  166  ( FIG. 21 ) or the circuitry of driver  166  may be incorporated into drive signal generator  170 . 
     A flow chart of illustrative steps involved in adjusting and using touch pad  20  is shown in  FIG. 34 . 
     At step  171 , default settings for touch pad  20  may be stored in storage and processing circuitry  160 . For example, firmware or other code may be embedded in a nonvolatile memory in storage and processing circuitry  160 . This code may include default settings for the force sensors, touch sensor array, and actuator of touch pad  20 . 
     User-adjustable settings may be gathered from a user at step  172 . For example, a user may supply settings using a key board, by pressing buttons, by sliding switches, by entering voice commands, or by interacting with on-screen options. Touch pad settings that may be adjusted by the user include application software settings, operating system settings, firmware settings, hardware settings, etc. These settings may include force signal processing settings, touch sensor settings, and driver settings of the types described in connection with  FIG. 33 . 
     At step  174 , touch pad data may be gathered from touch sensor  168  and force sensor circuitry  34 . This data may be gathered continuously during operation of device  10  (as an example). 
     At step  176 , the force data and touch data that is gathered at step  174  may be processed using the user-supplied and default force signal processing settings and user-supplied and default touch sensor processing settings. The processing operations of step  176  result in the production of processed force and touch sensor data (e.g., X-Y finger movement data and force-based button actuation data). 
     At step  178 , in response to the processing operations of step  176 , appropriate actions may be taken in device  10  and touch pad  20 . For example, an operating system or application program on device  10  may interpret a button press event as an instruction to open or close a displayed window, to start or stop a particular function, etc. Touch pad movement may be produced in response to the processing operation of step  176  by driving actuator  36  with appropriate control signals. The signals that are used to drive actuator  36  may be affected by the processed touch and force signals and by actuator settings (e.g., by default and user-supplied drive signal settings such as settings that dictate which of the actuator drive signals of  FIGS. 27-30  should be used in various situations, etc.). 
     Although sometimes described in the context of a touch pad in a portable computer, touch pad features of the types described herein may be used in any electronic equipment. The force sensor features of the touch pad may be used in devices with or without touch sensor capabilities and with or without an actuator, the touch sensor features may be used in devices with or without force sensor capabilities and with or without an actuator, and the actuator features may be used in devices with or without touch sensor capabilities and with or without force sensor capabilities. 
     Described embodiments may include a touch I/O device  1001  (sometimes referred to herein as a touch pad) that can receive touch input for interacting with a computing system  1003  ( FIG. 35 ) via a wired or wireless communication channel  1002 . Touch I/O device  1001  may be used to provide user input to computing system  1003  in lieu of or in combination with other input devices such as a keyboard, mouse, etc. One or more touch I/O devices  1001  may be used for providing user input to computing system  1003 . Touch I/O device  1001  may be an integral part of computing system  1003  (e.g., touch screen on a laptop) or may be separate from computing system  1003 . 
     Touch I/O device  1001  may include a touch sensitive panel which is wholly or partially transparent, semitransparent, non-transparent, opaque or any combination thereof. Touch I/O device  1001  may be embodied as a touch screen, touch pad, a touch screen functioning as a touch pad (e.g., a touch screen replacing the touchpad of a laptop), a touch screen or touchpad combined or incorporated with any other input device (e.g., a touch screen or touchpad disposed on a keyboard) or any multi-dimensional object having a touch sensitive surface for receiving touch input. 
     In one example, a touch I/O device  1001  embodied as a touch screen may include a transparent and/or semitransparent touch sensitive panel partially or wholly positioned over at least a portion of a display. According to this embodiment, touch I/O device  1001  functions to display graphical data transmitted from computing system  1003  (and/or another source) and also functions to receive user input. In other embodiments, touch I/O device  1001  may be embodied as an integrated touch screen where touch sensitive components/devices are integral with display components/devices. In still other embodiments a touch screen may be used as a supplemental or additional display screen for displaying supplemental or the same graphical data as a primary display and to receive touch input. 
     Touch I/O device  1001  may be configured to detect the location of one or more touches or near touches on device  1001  based on capacitive, resistive, optical, acoustic, inductive, mechanical, chemical measurements, or any phenomena that can be measured with respect to the occurrences of the one or more touches or near touches in proximity to device  1001 . Software, hardware, firmware or any combination thereof may be used to process the measurements of the detected touches to identify and track one or more gestures. A gesture may correspond to stationary or non-stationary, single or multiple, touches or near touches on touch I/O device  1001 . A gesture may be performed by moving one or more fingers or other objects in a particular manner on touch I/O device  1001  such as tapping, pressing, rocking, scrubbing, twisting, changing orientation, pressing with varying pressure and the like at essentially the same time, contiguously, or consecutively. A gesture may be characterized by, but is not limited to a pinching, sliding, swiping, rotating, flexing, dragging, or tapping motion between or with any other finger or fingers. A single gesture may be performed with one or more hands, by one or more users, or any combination thereof. 
     Computing system  1003  may drive a display with graphical data to display a graphical user interface (GUI). The GUI may be configured to receive touch input via touch I/O device  1001 . Embodied as a touch screen, touch I/O device  1001  may display the GUI. Alternatively, the GUI may be displayed on a display separate from touch I/O device  1001 . The GUI may include graphical elements displayed at particular locations within the interface. Graphical elements may include but are not limited to a variety of displayed virtual input devices including virtual scroll wheels, a virtual keyboard, virtual knobs, virtual buttons, any virtual UI, and the like. A user may perform gestures at one or more particular locations on touch I/O device  1001  which may be associated with the graphical elements of the GUI. In other embodiments, the user may perform gestures at one or more locations that are independent of the locations of graphical elements of the GUI. Gestures performed on touch I/O device  1001  may directly or indirectly manipulate, control, modify, move, actuate, initiate or generally affect graphical elements such as cursors, icons, media files, lists, text, all or portions of images, or the like within the GUI. For instance, in the case of a touch screen, a user may directly interact with a graphical element by performing a gesture over the graphical element on the touch screen. Alternatively, a touch pad generally provides indirect interaction. Gestures may also affect non-displayed GUI elements (e.g., causing user interfaces to appear) or may affect other actions within computing system  1003  (e.g., affect a state or mode of a GUI, application, or operating system). Gestures may or may not be performed on touch I/O device  1001  in conjunction with a displayed cursor. For instance, in the case in which gestures are performed on a touchpad, a cursor (or pointer) may be displayed on a display screen or touch screen and the cursor may be controlled via touch input on the touchpad to interact with graphical objects on the display screen. In other embodiments in which gestures are performed directly on a touch screen, a user may interact directly with objects on the touch screen, with or without a cursor or pointer being displayed on the touch screen. 
     Feedback may be provided to the user via communication channel  1002  in response to or based on the touch or near touches on the touch I/O device  1001 . Feedback may be transmitted optically, mechanically, electrically, olfactory, acoustically, or the like or any combination thereof and in a variable or non-variable manner. 
     Attention is now directed towards embodiments of a system architecture that may be embodied within any portable or non-portable device including but not limited to a communication device (e.g. mobile phone, smart phone), a multi-media device (e.g., MP3 player, TV, radio), a portable or handheld computer (e.g., tablet, netbook, laptop), a desktop computer, an All-In-One desktop, a peripheral device, or any other system or device adaptable to the inclusion of system architecture  2000 , including combinations of two or more of these types of devices.  FIG. 36  is a block diagram of one embodiment of a system  2000  that generally includes one or more computer-readable mediums  2001 , a processing system  2004 , an Input/Output (I/O) subsystem  2006 , radio frequency (RF) circuitry  2008  and audio circuitry  2010 . These components may be coupled by one or more communication buses or signal lines  2003 . 
     In some embodiments, the system  2000  may include the functionality of an MP3 player, such as an iPod (trademark of Apple Computer, Inc.). The system  2000  may, therefore, include a multiple-pin connector that is compatible with the iPod. In some embodiments, the system  2000  may include one or more optional optical sensors (not shown), such as CMOS or CCD image sensors, for use in imaging applications. 
     It should be apparent that the architecture shown in  FIG. 36  is only one example architecture of system  2000 , and that system  2000  could have more or fewer components than shown, or a different configuration of components. The various components shown in  FIG. 36  can be implemented in hardware, software, firmware or any combination thereof, including one or more signal processing and/or application specific integrated circuits. 
     The RF circuitry  2008  is used to send and receive information over a wireless link or network to one or more other devices and includes well-known circuitry for performing this function, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, memory, etc. In some embodiments, the RF circuitry  2008  is capable of establishing and maintaining communications with other devices using one or more communications protocols, including but not limited to time division multiple access (TDMA), code division multiple access (CDMA), global system for mobile communications (GSM), Enhanced Data GSM Environment (EDGE), wideband code division multiple access (W-CDMA), Wi-Fi (such as IEEE 802.11a, IEEE 802.11b, IEEE 802.11g and/or IEEE 802.11n), Bluetooth, Wi-MAX, HSDPA (High Speed Downlink Packet Access, voice over Internet Protocol (VoIP), a protocol for email, instant messaging, and/or a short message service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document. 
     The RF circuitry  2008  and the audio circuitry  2010  are coupled to the processing system  2004  via the peripherals interface  2016 . The interface  2016  includes various known components for establishing and maintaining communication between peripherals and the processing system  2004 . The audio circuitry  2010  is coupled to an audio speaker  2050  and a microphone  2052  and includes known circuitry for processing voice signals received from interface  2016  to enable a user to communicate in real-time with other users. In some embodiments, the audio circuitry  2010  includes a headphone jack (not shown). Voice and data information received by the RF circuitry  2008  and the audio circuitry  2010  (e.g., in speech recognition or voice command applications) is sent to one or more processors  2018  via the peripherals interface  2016 . The one or more processors  2018  are configurable to process various data formats for one or more applications programs  2030  stored on the medium  2001 . 
     The term “data” includes but is not limited to text, graphics, Web pages, JAVA applets, widgets, emails, instant messages, voice, digital images or video, widgets, MP3s, etc., which can be used by one or more applications programs  2030  stored on the medium  2001  (e.g., Web browser, email, etc.). In some embodiments, the system  2000  is capable of uploading and downloading various data from the Internet over a wireless network or an external port  2036 , such as files, songs, digital images, videos, emails, widgets, instant messages and the like. 
     The peripherals interface  2016  couples the input and output peripherals of the system to the processor  2018  and the computer-readable medium  2001 . The one or more processors  2018  communicate with the one or more computer-readable mediums  2001  via a controller  2020 . The computer-readable medium  2001  can be any device or medium that can store code and/or data for use by the one or more processors  2018 . The medium  2001  can include a memory hierarchy, including but not limited to cache, main memory and secondary memory. The memory hierarchy can be implemented using any combination of RAM (e.g., SRAM, DRAM, DDRAM), ROM, FLASH, magnetic and/or optical storage devices, such as disk drives, magnetic tape, CDs (compact disks) and DVDs (digital video discs). The medium  2001  may also include a transmission medium for carrying information-bearing signals indicative of computer instructions or data (with or without a carrier wave upon which the signals are modulated). For example, the transmission medium may include a communications network, including but not limited to the Internet (also referred to as the World Wide Web), intranet(s), Local Area Networks (LANs), Wide Local Area Networks (WLANs), Storage Area Networks (SANs), Metropolitan Area Networks (MAN) and the like. 
     The one or more processors  2018  run various software components stored in the medium  2001  to perform various functions for the system  2000 . In some embodiments, the software components include an operating system  2022 , a communication module (or set of instructions)  2024 , a touch processing module (or set of instructions)  2026 , a graphics module (or set of instructions)  2028 , one or more applications (or set of instructions)  2030 , and a force sensor and feedback module [or set of instructions]  2038 . Each of these modules and above noted applications correspond to a set of instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (i.e., sets of instructions) need not be implemented as separate software programs, procedures or modules, and thus various subsets of these modules may be combined or otherwise rearranged in various embodiments. In some embodiments, medium  2001  may store a subset of the modules and data structures identified above. Furthermore, medium  2001  may store additional modules and data structures not described above. 
     The operating system  2022  (e.g., Darwin, RTXC, LINUX, UNIX, OS X, Windows, or an embedded operating system such as VxWorks) includes various procedures, sets of instructions, software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components. 
     The communication module  2024  facilitates communication with other devices over one or more external ports  2036  or via RF circuitry  2008  and includes various software components for handling data received from the RF circuitry  2008  and/or the external port  2036 . The external port  2036  (e.g., USB, FireWire™, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc.). 
     The graphics module  2028  includes various known software components for rendering, animating and displaying graphical objects on a display surface. In embodiments in which touch I/O device  2012  is a touch sensitive display (e.g., touch screen), graphics module  2028  includes components for rendering, displaying, and animating objects on the touch sensitive display. Note that the term “graphical object” includes any object that can be displayed to a user, including without limitation text, web pages, icons, digital images, animations and the like. 
     The one or more applications  2030  can include any applications installed on the system  2000 , including without limitation, a browser, address book, contact list, email, instant messaging, word processing, keyboard emulation, widgets, JAVA-enabled applications, encryption, digital rights management, voice recognition, voice replication, location determination capability (such as that provided by the global positioning system (GPS)), a music player (which plays back recorded music stored in one or more files, such as MP3 or AAC files), etc. 
     The touch processing module  2026  includes various software components for performing various tasks associated with the touch I/O device  2012  including but not limited to receiving and processing touch input received from I/O device  2012  via touch I/O device controller  2032 . 
     System  2000  may further include force sensor and feedback module  2038  for performing the method/functions as described herein in connection with  FIGS. 33 and 34 . Force sensor and feedback module  2038  may at least function to receive and process touch and force data from force sensors and take actions in response (e.g., by driving actuators using actuator control signals). Module  2038  may be embodied as hardware, software, firmware, or any combination thereof. Although module  2038  is shown to reside within medium  2001 , all or portions of module  2038  may be embodied within other components within system  2000  or may be wholly embodied as a separate component within system  2000 . 
     The I/O subsystem  2006  is coupled to the touch I/O device  2012  and one or more other I/O devices  2014  for controlling or performing various functions, such as power control, speaker volume control, ring tone loudness, keyboard input, scrolling, hold, menu, screen lock, clearing and ending communications and the like. The touch I/O device  2012  communicates with the processing system  2004  via the touch I/O device controller  2032 , which includes various components for processing user touch input (e.g., scanning hardware). The one or more other input controllers  2034  receives/sends electrical signals from/to the other I/O devices  2014 . The other I/O devices  2014  may include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, sticks, keyboards, touch pads, additional display screens, or any combination thereof. 
     If embodied as a touch screen, the touch I/O device  2012  displays visual output to the user in a GUI. The visual output may include text, graphics, video, and any combination thereof. Some or all of the visual output may correspond to user-interface objects. The touch I/O device  2012  forms a touch-sensitive surface that accepts touch input from the user. The touch I/O device  2012  and the touch screen controller  2032  (along with any associated modules and/or sets of instructions in the medium  2001 ) detects and tracks touches or near touches (and any movement or release of the touch) on the touch I/O device  2012  and converts the detected touch input into interaction with graphical objects, such as one or more user-interface objects. In the case in which device  2012  is embodied as a touch screen, the user can directly interact with graphical objects that are displayed on the touch screen. Alternatively, in the case in which device  2012  is embodied as a touch device other than a touch screen (e.g., a touch pad), the user may indirectly interact with graphical objects that are displayed on a separate display screen embodied as an I/O device  2014 . In an exemplary embodiment, touch input received from a user by the touch I/O device  2012  corresponds to one or more digits of the user. The touch I/O device  2012  and touch I/O device controller  2032  may detect touch input using any of a plurality of touch sensitivity technologies, including but not limited to capacitive, resistive, infrared, optical, surface acoustic wave technologies, inductive, mechanical, chemical as well as other touch sensor arrangements or other elements for determining one or more touches or near touches on the touch I/O device  2012 . The user may make contact with the touch I/O device  2012  using any suitable object or appendage, such as a stylus, pen, finger, and so forth. 
     The touch I/O device  2012  may be analogous to the multi-touch sensitive surface described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference. 
     Embodiments in which the touch I/O device  2012  is a touch screen, the touch screen may use LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, OLED (organic LED), or OEL (organic electro luminescence), although other display technologies may be used in other embodiments. 
     In some embodiments, in which device  2012  is embodied as a touch screen, the system  2000  may further include a touchpad embodied as other I/O device  2014 . In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. In this case, the touchpad is separate from the touch screen. Alternatively, the touch pad may be embodied as a touch screen. In still other embodiments, portions of a touch screen may include non-display areas (e.g., along the periphery of the touch screen) that function as a touch pad to receive touch input other than on the touch screen. 
     Feedback may be provided by the touch I/O device  2012  based on the user&#39;s touch input as well as a state or states of what is being displayed and/or of the computing system. Feedback may be transmitted optically (e.g., light signal or displayed image), mechanically (e.g., haptic feedback, touch feedback, force feedback, or the like), electrically (e.g., electrical stimulation), olfactory, acoustically (e.g., beep or the like), or the like or any combination thereof and in a variable or non-variable manner. 
     The system  2000  also includes a power system  2044  for powering the various hardware components. The power system  2044  can include a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light emitting diode (LED)) and any other components typically associated with the generation, management and distribution of power in portable devices. 
     In some embodiments, the peripherals interface  2016 , the one or more processors  2018 , and the memory controller  2020  may be implemented on a single chip, such as the processing system  2004 . In some other embodiments, they may be implemented on separate chips. 
     One or more gestures may be performed on touch I/O device  1001  at essentially the same time. Multiple gestures may be performed in a single uninterrupted stroke. Alternatively, a single gesture may be made up of multiple segmented sub-gestures such as a “cut and paste” gesture. The same gesture performed on different regions on touch I/O device  1001  may provide different touch input to computing system  1003  dependent on the region where the gesture is being performed. 
     It should be noted that although the above description of a touch surface has been described wherein the one or more touch or near touches correspond to a user&#39;s finger touching or near touching the surface, it should be understood that other objects may be used to provide touch input to touch I/O device  1001  including one or more other user body parts (e.g., palm, whole hand, head, nose, ear, feet, fingernail), a passive or active stylus, a document, an object shadow (e.g., a finger shadow), a non-conductive or conductive object, a passive or active object, a multi-dimensional object, or any combination thereof. An example of an active stylus may include a light pen. In addition, more than one type of object can be used at the same time or at different times to provide touch input to touch I/O device  1001 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20150217
Publication Date: 20160726
Grant Date: 20160726
Priority Date: 20091210
Inventors: BERNSTEIN JEFFREY TRAER
CIEPLINSKI AVI
DEGNER BRETT W.
KERR DUNCAN
KESSLER PATRICK
PUSKARICH PAUL
COELHO MARCELO H.
PANCE ALEKSANDAR
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G5/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G5/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1692", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0227", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/045", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0446", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1692", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "A63B2022/0092", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "A63B2022/0092", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0227", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1613", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 43858036