PATENT DOCUMENT

Publication Number: US-9971407-B2
Application Number: US-201514870697-A
Country: US
Kind Code: B2

Title: Haptic feedback for rotary inputs

Abstract:
An electronic device is disclosed. In some examples, the electronic device comprises a mechanical input configured to rotate in a first direction about a rotation axis in response to a first input at the mechanical input. In some examples, the electronic device comprises a mechanical input sensor coupled to the mechanical input and configured to sense a rotation of the mechanical input about the rotation axis. In some examples, the electronic device comprises a mechanical input actuator coupled to the mechanical input and configured to rotate the mechanical input in a second direction about the rotation axis. In some examples, the mechanical input comprises a shared driving and sensing segment. In some examples, the mechanical input sensor is configured to sense the rotation of the mechanical input at the shared driving and sensing segment. In some examples, the mechanical input actuator is configured to generate magnetic fields for rotating the mechanical input at the shared driving and sensing segment. In some examples, the mechanical input is further configured to translate along the rotation axis in response to a second input. In some examples, the mechanical input actuator comprises at least one piezoelectric element configured to allow the mechanical input to translate along the rotation axis. In some examples, the mechanical input actuator comprises at least one piezoelectric element configured to rotate the mechanical input in the second direction about the rotation axis.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a mechanical input configured to rotate in a first direction about a rotation axis in response to a first input at the mechanical input; 
 an actuator coupled to the mechanical input and configured to generate magnetic fields for rotating the mechanical input in a second direction about the rotation axis, 
 a mechanical input sensor coupled to the mechanical input and configured to sense a rotation of the mechanical input about the rotation axis, wherein sensing the rotation of the mechanical input at the mechanical input sensor occurs through a gap in a drive coil arrangement disposed around the mechanical input; and 
 wherein a drive pattern for generating magnetic fields in the drive coil arrangement is configured to provide a first drive sequence when a first portion of the mechanical input is located near the drive coil arrangement, and to provide a second drive sequence when the first portion of the mechanical input is located near the gap. 
 
     
     
       2. The electronic device of  claim 1 , wherein the mechanical input comprises a shared driving and sensing element and the shared driving and sensing segment includes at least one magnet. 
     
     
       3. The electronic device of  claim 1 , wherein the first portion of the mechanical input corresponds to a location of a magnet included in the mechanical input. 
     
     
       4. The electronic device of  claim 1 , wherein:
 the mechanical input sensor comprises an optical sensor configured to sense the rotation of the mechanical input by sensing movement of a pattern disposed on the shared driving and sensing element through the gap, and at least a portion of the pattern disposed on the shared driving and sensing element corresponds to a location of a magnet included in the shared driving and sensing element. 
 
     
     
       5. The electronic device of  claim 1 , wherein the mechanical input is configured to translate along the rotation axis in response to a second input. 
     
     
       6. A non-transitory computer readable storage medium having stored thereon a set of instructions, that when executed by a processor causes the processor to:
 sense a rotation of a mechanical input in a first direction about a rotation axis resulting from an input at the mechanical input, wherein sensing the rotation occurs through a gap in a drive coil arrangement disposed around the mechanical input; and 
 rotate the mechanical input in a second direction about the rotation axis by providing a first drive sequence for generating magnetic fields in the drive coil arrangement when a first portion of the mechanical input is located near the drive coil arrangement and providing a second drive sequence when the first portion of the mechanical input is located near the gap. 
 
     
     
       7. The non-transitory computer readable storage medium of  claim 6 , wherein:
 the mechanical input comprises a shared driving and sensing element and the shared driving and sensing element includes at least one magnet. 
 
     
     
       8. The non-transitory computer readable storage medium of  claim 6 , wherein the mechanical input is configured to translate along the rotation axis in response to a second input. 
     
     
       9. The non-transitory computer readable storage medium of  claim 6 , wherein the first portion of the mechanical input corresponds to a location of a magnet included in the mechanical input. 
     
     
       10. The non-transitory computer readable storage medium of  claim 6 , wherein:
 the mechanical input sensor comprises an optical sensor configured to sense the rotation of the mechanical input by sensing movement of a pattern disposed on the shared driving and sensing element through the gap, and at least a portion of the pattern disposed on the shared driving and sensing element corresponds to a location of a magnet included in the shared driving and sensing element. 
 
     
     
       11. A method comprising the steps of:
 sensing a rotation of a mechanical input in a first direction about a rotation axis resulting from an input at the mechanical input, wherein sensing the rotation occurs through a gap in a drive coil arrangement disposed around the mechanical input; and 
 rotating the mechanical input in a second direction about the rotation axis by providing a first drive sequence for generating magnetic fields in the drive coil arrangement when a first portion of the mechanical input is located near the drive coil arrangement and providing a second drive sequence when the first portion of the mechanical input is located near the gap. 
 
     
     
       12. The method of  claim 11 , wherein:
 the mechanical input comprises a shared driving and sensing element and the shared driving and sensing element includes at least one magnet. 
 
     
     
       13. The method of  claim 11 , wherein the mechanical input is configured to translate along the rotation axis in response to a second input. 
     
     
       14. The method of  claim 11 , wherein the first portion of the mechanical input corresponds to a location of a magnet included in the mechanical input. 
     
     
       15. The method of  claim 11 , wherein:
 the mechanical input sensor comprises an optical sensor configured to sense the rotation of the mechanical input by sensing movement of a pattern disposed on the shared driving and sensing element through the gap, and at least a portion of the pattern disposed on the shared driving and sensing element corresponds to a location of a magnet included in the shared driving and sensing element.

Description:
FIELD OF THE DISCLOSURE 
     This relates generally to user inputs, such as mechanical inputs, and more particularly, to providing haptic feedback on such inputs. 
     BACKGROUND OF THE DISCLOSURE 
     Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch and the position of the touch on the touch sensor panel, and the computing system can then interpret the touch in accordance with the display appearing at the time of the touch, and thereafter can perform one or more actions based on the touch. In the case of some touch sensing systems, a physical touch on the display is not needed to detect a touch. For example, in some capacitive-type touch sensing systems, fringing electrical fields used to detect touch can extend beyond the surface of the display, and objects approaching near the surface may be detected near the surface without actually touching the surface. However, devices that accept non-mechanical inputs, such as capacitive touch input, often do not provide tactile feedback to a user. 
     In addition to touch panels/touch screens, many electronic devices may also have mechanical inputs, such as buttons, switches, and/or knobs. These mechanical inputs can control power (i.e., on/off) and volume for the electronic devices, among other functions. However, sometimes these mechanical inputs also fail to give a user tactile feedback, such as the “click-click-click” feeling of winding a mechanical watch crown. 
     SUMMARY OF THE DISCLOSURE 
     Some electronic devices may include mechanical inputs, such as buttons, switches, and/or knobs. These mechanical inputs can control power (i.e., on/off) and volume for the electronic devices, among other functions. However, sometimes these mechanical inputs can fail to give a user tactile feedback, such as the “click-click-click” feeling of winding a mechanical watch with a knob. It can be beneficial to provide haptic or tactile feedback to a user who is interacting with a mechanical input of an electronic device to give the user a richer interaction experience with the device. Accordingly, examples of the disclosure are directed to providing haptic feedback on mechanical inputs. In some examples, such haptic feedback can constitute giving the user a sensation that the user&#39;s finger is moving over a ridge, bump or valley feature on an otherwise smooth surface. This type of sensation can simulate the feeling of the user rotating a mechanical knob against the teeth of an internal gear (e.g., the feeling of a detent when turning a rotary input, such as the “click-click-click” feeling of winding a mechanical watch). In some examples, such as when a user is rotating a mechanical knob, haptic feedback can constitute giving the user a sensation of increased or decreased resistance to rotation of the mechanical knob. Haptic feedback as described above can give the user feedback about the effect of the user&#39;s input on the electronic device, such as changing the zoom-scale of content displayed on the device in response to the user&#39;s rotary input. In some examples, the above haptic feedback can be provided to the user via rotational displacement of a mechanical input that is opposite to the direction of the rotational movement of the mechanical input provided by the user (e.g., counter rotation of a rotary input that is opposite to the rotary input&#39;s rotational movement). Various examples of the above are provided in the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary device in which the haptic feedback of the disclosure can be implemented according to examples of the disclosure. 
         FIG. 2  illustrates a block diagram of components within an exemplary device according to examples of the disclosure. 
         FIG. 3  illustrates a diagram of various components of an optical encoder that may be used to receive crown position information according examples of the disclosure. 
         FIG. 4  illustrates an exemplary finger interacting with a protruding rotary input according to examples of the disclosure. 
         FIGS. 5A-5C  illustrate exemplary devices including a mechanical input sensor and mechanical input actuator for providing haptic feedback and finger-on-crown detection according to examples of the disclosure. 
         FIGS. 6A-6C  illustrate an exemplary DC motor haptic feedback configuration for providing haptic feedback according to examples of the disclosure. 
         FIGS. 7A-7C  illustrate various examples of magnetic drive implementations for providing haptic feedback according to examples of the disclosure. 
         FIG. 8  illustrates an exemplary piezoelectric haptic feedback configuration for providing haptic feedback according to examples of the disclosure. 
         FIGS. 9A-9D  illustrate various examples of a piezoelectric implementations for providing haptic feedback according to examples of the disclosure. 
         FIG. 10  illustrates an example process for implementing haptic feedback according to examples of the disclosure. 
         FIG. 11  illustrates an example process for implementing finger-on-crown detection according to examples of the disclosure. 
         FIG. 12  illustrates an example computing system for implementing haptic feedback according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of the disclosure and examples, reference is made to the accompanying drawings in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be practiced and structural changes can be made without departing from the scope of the disclosure. 
       FIG. 1  illustrates exemplary personal electronic device  100  in which the haptic feedback of the disclosure can be implemented according to examples of the disclosure. In the illustrated example, device  100  is a watch that generally includes body  102  and strap  104  for affixing device  100  to the body of a user. That is, device  100  is wearable. Body  102  can be designed to couple to straps  104 . Device  100  can have touch-sensitive display screen  106  (hereafter touchscreen) and crown  108 . Device  100  can also have buttons  110 ,  112 , and  114 . Though device  100  is illustrated as being a watch, it is understood that the examples of the disclosure can be implemented in devices other than watches, such as tablet computers, mobile phones, or any other wearable or non-wearable electronic device that can include a rotary input such as a crown  108  and/or a rotating bezel (not shown). 
     Conventionally, the term ‘crown,’ in the context of a watch, can refer to the cap atop a stem or shaft for winding the watch. In the context of a personal electronic device  100 , the crown can be a physical component of the electronic device, rather than a virtual crown on a touch sensitive display. Crown  108  can be mechanical, meaning that it can be connected to a sensor for converting physical movement of the crown into electrical signals. Crown  108  can rotate in two directions of rotation (e.g., forward and backward, or clockwise and counter-clockwise). Crown  108  can also be pushed in towards the body  102  of device  100  and/or be pulled away from the device. Crown  108  can be touch-sensitive, for example, using capacitive touch technologies or other suitable technologies that can detect whether a user is touching the crown. Moreover, crown  108  can further be configured to tilt in one or more directions or slide along a track at least partially around a perimeter of body  102 . In some examples, more than one crown  108  can be included in device  100 . The visual appearance of crown  108  can, but need not, resemble crowns of conventional watches. Buttons  110 ,  112 , and  114 , if included, can each be a physical or a touch-sensitive button. That is, the buttons may be, for example, physical buttons or capacitive buttons. Further, body  102 , which can include a bezel, may have predetermined regions on the bezel that act as buttons. In some examples, body  102  can include a rotating bezel (not shown) that can be positioned around a perimeter of display  106 , and can be rotated around the perimeter by a user. In some examples, the visual appearance of rotating bezel can, but need not, resemble rotating bezels in conventional watches. In some examples, the rotating bezel can be configured to perform analogous input operations and behaviors as the crown  108  (i.e., rotation in two directions of rotation, pushing toward and/or pulling away from the device, etc.). In some examples, other rotating input configurations can be used analogously as mechanical inputs to device  100 . 
     Display  106  can include a display device, such as a liquid crystal display (LCD), light-emitting diode (LED) display, organic light-emitting diode (OLED) display, or the like, positioned partially or fully behind or in front of a touch sensor panel implemented using any desired touch sensing technology, such as mutual-capacitance touch sensing, self-capacitance touch sensing, resistive touch sensing, projection scan touch sensing, or the like. Display  106  can allow a user to perform various functions by touching or hovering near the touch sensor panel using one or more fingers or other objects. 
     In some examples, device  100  can further include one or more pressure sensors (not shown) for detecting an amount of force or pressure applied to the display  106 . The amount of force or pressure applied to display  106  can be used as an input to device  100  to perform any desired operation, such as making a selection, entering or exiting a menu, causing the display of additional options/actions, or the like. In some examples, different operations can be performed based on the amount of force or pressure being applied to display  106 . The one or more pressure sensors can further be used to determine a position of the force that is being applied to display  106 . 
       FIG. 2  illustrates an exemplary block diagram of components within an exemplary device  200  according to examples of the disclosure. In some examples, crown  208  (which can correspond to crown  108  described above) can be coupled to encoder  204 , which can be configured to monitor a physical state or change of physical state of the crown (e.g., the position and/or rotational state of the crown), convert it to an electrical signal (e.g., convert it to an analog or digital signal representation of the position or change in position of the crown), and provide the signal to processor  202 . For instance, in some examples, encoder  204  can be configured to sense the absolute rotational position (e.g., an angle between 0-360°) of crown  208  and output an analog or digital representation of this position to processor  202 . Alternatively, in other examples, encoder  204  can be configured to sense a change in rotational position (e.g., a change in rotational angle) of crown  208  over some sampling period and to output an analog or digital representation of the sensed change to processor  202 . In these examples, the crown position information can further indicate a direction of rotation of the crown  208  (e.g., a positive value can correspond to one direction and a negative value can correspond to the other). In yet other examples, encoder  204  can be configured to detect a rotation of crown  208  in any desired manner (e.g., velocity, acceleration, or the like) and can provide the crown rotational information to processor  202 . The rotational velocity can be expressed in numerous ways. For example, the rotational velocity can be expressed as a direction and a speed of rotation, such as hertz, as rotations per unit of time, as rotations per frame, as revolutions per unit of time, as revolutions per frame, as a change in angle per unit of time, and the like. In alternative examples, instead of providing information to processor  202 , this information can be provided to other components of device  200 , such as, for example, a state machine. While the examples described herein refer to the use of rotational position of crown  208  to control scrolling or scaling of a view, it should be appreciated that any other physical state of the crown can be used to control appropriate actions. 
     In some examples, the state of the display  206  (which can correspond to display  106  described above) can control physical attributes of crown  208 . For example, if display  206  shows a cursor at the end of a scrollable list, crown  208  can have limited motion (e.g. cannot be rotated forward). In other words, the physical attributes of the crown  208  can be conformed to a state of a user interface that is displayed on display  206 . The mechanisms for controlling the physical attributes of the crown are described in further detail below. In some examples, a temporal attribute of the physical state of crown  208  can be used as an input to device  200 . For example, a fast change in physical state can be interpreted differently than a slow change in physical state. These temporal attributes can also be used as inputs to control physical attributes of the crown. 
     Processor  202  can be further coupled to receive input signals from buttons  210 ,  212 , and  214  (which can correspond to buttons  110 ,  112 , and  114 , respectively), along with touch signals from touch-sensitive display  206 . Processor  202  can be configured to interpret these input signals and output appropriate display signals to cause an image to be produced by touch-sensitive display  206 . While a single processor  202  is shown, it should be appreciated that any number of processors or other computational devices can be used to perform the functions described above. 
       FIG. 3  illustrates an exemplary block diagram of various components of an optical encoder  304  that can be used to receive crown position information according to examples of the disclosure. The optical encoder  304  shown in  FIG. 3  may correspond to the encoder  204  described above, or may be used in conjunction with the encoder  204  described above. In various electronic devices, rotational and/or axial movement of a component (e.g., a crown) of the electronic device may need to be determined. In such instances, an optical encoder  304  may be used to detect the rotational movement and the axial movement of the component. For example, an optical encoder  304  according to examples of the disclosure can include a light source  318  that shines on a wheel  316  (also referred to as an encoder wheel) or a shaft of the optical encoder. The wheel  316  (or shaft) may include an encoding pattern, such as, for example, a collection of light and dark lines that are arranged in a particular sequence or in a particular pattern. In some examples, the wheel  316  may be integrated with or attached by a shaft to the crown  108  described above. 
     When light from the light source  318  hits the encoding pattern, the encoding pattern can modulate the light and reflect it onto one or more sensors  320  associated with the optical encoder. In certain embodiments, the one or more sensors  320  may be an array of photodiodes (PD). As light from the light source  318  is reflected off the wheel  316 , one or more photodiodes of the photodiode array  320  can produce a voltage measurement associated with an amount of light received at a given sample time. Once the light is received by the photodiode array  320  at a given time period, an analog-to-digital circuit  310  can convert the analog signal received from the photodiode array to a digital signal. The corresponding digital signals can be processed, and a determination may be made as to the direction, speed and/or movement (rotational and/or axial) of the wheel. In some examples, the direction and/or speed of the rotation information can be used in combination with the haptic feedback mechanisms described in the disclosure to improve interactivity of the user experience. For example, as the user rotates the crown, the haptic feedback circuit can provide a small counter-rotation in the opposite direction. This counter rotation can provide the user with a “click-click-click” feeling of winding a mechanical watch, for example. 
       FIG. 4  illustrates an exemplary finger  414  interacting with a protruding rotary input  408  according to examples of the disclosure.  FIG. 4  depicts an exemplary rotary input  408  (which can correspond to crown  108  and/or a rotating bezel above) that can rotate in rotational direction  422  as well as be displaced in direction  424 , i.e. translated along the direction of the rotation axis toward and/or away from a device (e.g., device  100  above), according to examples of the disclosure. In some examples, it can be beneficial to provide haptic or tactile feedback to a user who is interacting with a device (e.g., providing a mechanical input to the device), to give the user a richer interaction experience with the device. Finger  414  can be resting on rotary input  408 , and can be providing rotational input to the rotary input in rotational direction  422 . In addition to being able to rotate in rotational direction  422 , rotary  408  input can also have the ability to be displaced along direction  424 , (corresponding to movement along the y-axis in  FIG. 4 ), orthogonal to rotational direction  422  and the movement of finger  414 . In some examples, displacement or translation along direction  424  can be used to activate a translational input (e.g. pushing the rotary input inward along direction  424  can behave as a button input). In some examples, the translational input can be activated when a translational input component is compressed. In some examples, rotary input  408  can be displaced by an actuator in rotational direction  422  in a direction opposite to the rotational input provided by finger  414 . Examples of these actuators and their operation are described in further detail below. The displacement of rotary input in the rotational direction opposite to the direction of the finger movement can cause stretching and/or compression of portion  416  of finger  414  that is touching rotary input  408 , and can simulate the feeling of a ridge or detent (e.g., the clicking of a rotary input) associated with the rotary input. In some examples, limiting the displacement of rotary input  408  along the rotational direction  422  to be a relatively small displacement (e.g., 15 degrees or less) can be most effective in simulating the above ridges or detents. In some examples, providing the displacement of rotary input  408  along the rotational direction  422  for a relatively short duration (e.g., 100 milliseconds or less) can be most effective in simulating the above ridges or detents. The speed, duration, strength, density and any other characteristic of the displacement of rotary input  408  along rotational direction  422  can be adjusted dynamically to provide a range of haptic feedback to the user, from continuous texture-like sensations to individual clicks or ridges on the rotary input to no haptic feedback at all to allow a smooth rotation of the rotary input. Alternatively, rotation of rotary input  408  can be resisted, for example by providing a sustained displacement opposite to the rotational direction  422  being provided by the user that is proportional to the amount of force being input by the user. In some examples rotation of the rotary input  408  can be resisted by increasing the amount of friction resisting rotation of the rotary input, as will be described in further detail below. In some examples, rotation of the rotary input  408  can instead be assisted, for example, by providing a displacement in the same rotational direction  422  being provided by the user. In some examples, a rotation can be initiated by the user, and the rotation can be continued in the same rotational direction  422  without the user providing additional rotation. In some examples, the continued displacement can be stopped when the user provides an additional input to the rotary input (e.g. a tap). 
       FIGS. 5A-5C  illustrate exemplary devices  500  including a mechanical input sensor  528  and mechanical input actuator  530  (or a combined mechanical input sensor and actuator  532 ) for providing haptic feedback according to examples of the disclosure. Mechanical input sensor  528  can be coupled to rotary input  508  (which can correspond to crown  108  in  FIG. 1  and/or a rotating bezel described above) and can sense the rotational movement of the rotary input along rotational direction  522 . In some examples, rotary input  508  can be coupled to mechanical input actuator  530  by shaft  531 . Mechanical input actuator  530  can be coupled to shaft  531  and can provide displacement of the shaft and thus rotary input  508 , along rotational direction  522 . In some examples, mechanical input actuator  530  can be coupled directly to mechanical input  508  and/or coupled to other components that can be mechanically attached to the mechanical input. Mechanical input actuator  530  can be in communication with mechanical input sensor  528  such that the mechanical input actuator can have access to the input information provided by rotation of rotary input  508 . Mechanical input actuator  530  and/or mechanical input sensor  528  can be programmable such that any number of characteristics of the displacement of rotary input  508  along rotational direction  522  can be adjusted. For example, the amplitude of the displacement, the duration of the displacement, the frequency of the displacement (e.g., every 30 degrees of rotation), the velocity of the displacement, and any other characteristic of the displacement can be dynamically varied to provide the desired user experience on device  500 . In some examples, a clockwise rotation can be considered a positive amount of rotation and a counter-clockwise rotation can be considered a negative amount of rotation. To simulate a “click” at rotatory input  508 , for example, if a threshold amount of rotation (e.g. every 30 degrees) is exceeded, counter-rotation can be induced in a clockwise direction, while if it is determined that the amount of rotation exceeds the threshold amount of rotation in the positive direction, the counter-rotation can be induced in a counter-clockwise direction. 
     In some examples, the characteristics of the displacement of rotary input  508  along rotational direction  522  by mechanical input actuator  530  can be based on the context of device  500 . For example, if device  500  is displaying a mapping application, rotary input  508  can be used to zoom into and out of a displayed map. In such circumstances, mechanical input actuator  530  can provide a counter-rotation of rotary input  508  along rotational direction  522  each time the scale of the map is changed in response to the rotational input of the rotary input (e.g., switching from a five-mile scale to a one-mile scale), so as to simulate a click of the rotary input (e.g., a detent) and to provide the user haptic feedback that the scale of the map has been changed. In another example, when the scale of the map has reached the maximum or minimum zoom level available, resistance can be applied to rotation of the rotary input  508  to notify the user that additional rotation in a particular direction will have no additional effect. In another example, the mechanical input actuator  530  can assist or maintain a rotation after receiving a user input. For example, if device  500  is displaying a word processing application, rotary input  508  can be used to scroll through a document. In such circumstances, mechanical input actuator  530  can provide an assisting rotation along rotational direction  522  to facilitate easier scrolling through large documents. In one example, the mechanical input actuator can provide a rotation in the same direction as the user input rotation (e.g., every 30 degrees) to reduce the amount of effort a user must provide to continuously rotate the rotary input  508 . In other examples, the user can provide a rapid input (i.e., 180 degrees in 0.1 seconds), and the rapid input can trigger the mechanical input actuator  530  to provide a continuous rotation to the rotary input  508 , which can maintain the scrolling action initiated by the user. In some examples, the rotation provided by the mechanical input actuator  530  can be halted by an additional user input, such as a user tapping the crown or resisting the mechanical input actuator&#39;s rotation. 
     As another example, if device  500  is running and displaying a timing application, rotary input  508  can be used to set the duration of a timer. In such circumstances, mechanical input actuator  530  can provide counter-rotation of rotary input  508  along rotational direction  522  each time the duration of the timer is changed by a predetermined amount (e.g., every minute, every five minutes, etc.) in response to the rotational input of the rotary input, so as to simulate a click of the rotary input (e.g., a detent) and to provide the user haptic feedback indicating that the duration of the timer has been changed by a predetermined amount. Other circumstances in which the characteristics of the displacement of rotary input  508  along rotational direction  522  can be based on the context of device  500  (e.g., the current state of the device, what application(s) are running on the device, what user interface(s) are being displayed on the device, etc.) are similarly within the scope of the disclosure. 
       FIG. 5B  illustrates an exemplary device  500  in which the mechanical input sensor  528  and mechanical input actuator  530  can be combined into a single mechanical input sensor and actuator  532  for providing haptic feedback according to examples of the disclosure. While the examples below may be explained in terms of a separate mechanical input sensor  528  and mechanical input actuator  530 , the same or similar principles can be applied if the mechanical input sensor and mechanical input actuator are combined in the mechanical input sensor and actuator  532 . Alternatively, mechanical input sensor  528  and mechanical input actuator  530  can be connected to one or more processors (not shown) responsible for coordinating their operation. 
       FIG. 5C  illustrates an exemplary device  500  for detecting a user contact with rotary input  508  according to examples of the disclosure. Device  500  can receive rotary user input from a finger  514  at a contact point  516  on rotary input  508 . In some examples, the mechanical input sensor  528  can be used along with the mechanical input actuator  530  to detect whether a user is in contact with the rotary input  508 . While a finger  514  in contact with the rotary input  508  may appear to be stationary in a position on the rotary input, small movements of the finger that can be imperceptible to the human eye may cause the finger to generate corresponding small movements in the rotary input. These small movements can be the result of constant adjustments in the human body motor control system required for stabilization. The movements can also be viewed as small natural oscillations in body position or position of extremities such as fingers. These movements can be referred to as micro-tremors. The micro-tremors can in some examples cause very small back and forth rotation of the crown. In some examples, the micro-tremors can cause small movements of the crown in any direction that the rotary input  508  is free to move, including the directions of movement (e.g., movement in and out, tilting, or sliding) described with respect to  FIG. 1  above. Although in some examples these micro-tremors are imperceptible to the human eye, the corresponding movement in the rotary input  508  caused by the micro-tremors can be perceptible to the mechanical input sensor  528 . In some examples, if the mechanical input sensor  528  detects a micro-tremor indicative of contact by a user&#39;s finger  514 , the mechanical input sensor can indicate a finger-on-crown condition (e.g., the device  500  can determine that a finger is in contact with rotary input  508 ). In some examples, the finger-on-crown condition can be indicated if the detected micro-tremor creates an oscillation with a frequency between 10 Hz and 20 Hz. In other examples, a wider frequency range can be used that can account for a larger range of natural oscillation frequency for different users. In yet other examples, calibration can be performed to detect the natural oscillation characteristics of a particular user. In some examples, this calibration can be completed by detecting movement in the rotary input  508  when the user&#39;s finger is in contact with the crown and storing the detected movement (e.g. a movement pattern, amplitude, and/or frequency). The mechanical input sensor  528  can be configured to compare movement in the rotary input  508  with the stored movement pattern and determine whether the detected micro-tremor falls within a matching threshold of the stored movement (e.g., the movement pattern, amplitude, and/or frequency). If the result of the comparison is within the matching threshold, the mechanical input sensor  528  can associate the micro-tremor with the user. This can prevent erroneous finger-on-crown indications, or in some examples can be used to identify that a particular user is contacting the crown. 
     In some examples, the finger-on-crown detection described above can be enhanced by the exemplary configuration of device  500  in  FIG. 5C . Specifically, in some circumstances, a user&#39;s micro-tremor may not create a detectable corresponding movement in the rotary input  508  due, for example, to assembly and manufacturing tolerances. For example, the rotary input  508  can be seated in a device&#39;s housing such that the crown experiences a relatively high amount of friction that resists movement of the crown, and the user&#39;s micro tremor may not generate sufficient force to cause sufficient motion (e.g. rotation, movement in and out, tilt, sliding, etc.) in a resting crown to be detected by the mechanical input sensor  528 . In some examples, the mechanical input actuator  530  can be used to enhance the above described finger-on-crown detection capability. In some examples, the user&#39;s micro-tremor can be detectable without enhancement, but the mechanical input actuator  530  can still be used to enhance the above described finger-on-crown detection capability. In some examples, a micro-oscillation can be induced in the crown  508  by the mechanical input actuator  530 . In some examples, the micro-oscillation (e.g. an oscillating micro-rotation) can occur with an amplitude that is imperceptible to the human eye, while being detectable by the mechanical input sensor  528 . In some examples, the micro-oscillations can cause small movements of the crown in any direction that the rotary input  508  is free to move, including the directions of movement (e.g., rotation, movement in and out, tilting, or sliding) described regarding  FIG. 1  above. In some examples, the micro-oscillation can be induced at a frequency between 10 Hz and 20 Hz. In other examples, the micro-oscillation can be induced to match a user-specific frequency detected during a calibration operation. In some examples, any frequency of oscillation within a range reasonably expected to correspond with a natural human oscillation can be induced in the crown. In some examples, the mechanical input actuator  530  can rotate the rotary input  508  at a desired frequency of oscillation with sufficient rotational force to generate an amount of rotation in the crown that is detectable by the mechanical input sensor  528 . In some instances, depending on manufacturing tolerances as described above, the mechanical input actuator  530  can apply a greater amount of force than the natural oscillations of a typical user to overcome a relatively high amount of friction in the rotary input  508 , while in other examples the mechanical input actuator can rotate the crown with only a relatively low amount of force compared to the natural oscillations of a typical user. In some examples, the micro-oscillation can be applied continuously by the mechanical input actuator  530 , while in other examples the micro-oscillation can be applied periodically to conserve power. In other examples, the micro-oscillation can be applied in response to a command from an application running on device  500  requesting finger-on-crown information. 
     The micro-oscillations applied to the rotary input  508  by the mechanical input actuator  530  described above can enhance finger-on-crown detection capability when a user&#39;s finger comes in contact with the crown. Since the applied micro-oscillation can be applied at a frequency similar to a user&#39;s natural oscillation frequency, in some examples the two oscillations (e.g. the micro-oscillation and the micro-tremor) can constructively or destructively interfere. The mechanical input sensor  528  can be configured to detect constructive or destructive interference to detect a finger-on-crown condition. In some examples, constructive interference can lead to an increase of the amplitude of oscillation detected by mechanical input sensor  528  and destructive interference can lead to a decrease of the amplitude of oscillation detected by mechanical input sensor. Such constructive or destructive interference can be partial or complete, or can be detected as a heterodyning of the two oscillation frequencies. Therefore, in some examples, the mechanical input sensor  528  can indicate a finger-on-crown condition if the amplitude of oscillation detected by the mechanical input sensor falls below and/or goes above a specified threshold of the induced micro-oscillations (e.g., 25% higher or lower than the induced micro-oscillation amplitude). In some examples, the frequency of the mechanical input actuator  530  induced micro-oscillation can be viewed as a local oscillator frequency. In other examples, while the micro-oscillation may be consciously imperceptible to the user, a resonance may be formed between the user&#39;s micro-tremor and the induced oscillation. In some examples, the resonance can result in a dramatic increase in the amplitude of oscillation of rotary input  508  at a resonance frequency. In some examples the resonance can be considered an extreme case of constructive interference. This resonance can also be detected as an amplitude of oscillation above a certain threshold by the mechanical input sensor  528  to indicate a finger-on-crown condition. 
       FIG. 6A  illustrates a perspective view of an exemplary DC motor haptic feedback configuration for providing haptic feedback to a rotatable shaft  626  according to examples of the disclosure. In some examples, the rotatable shaft  626  can be attached to a crown  608  and a rotor  616 . The shaft  626  can pass through a housing (not shown) of a portable electronic device, connecting the crown  608  on the outside of the device to the rotor  616  on the inside of the device. In some examples, magnets  628  (e.g., permanent magnets) can be embedded within the rotor  616 . The permanent magnet  628  poles can be arranged to form an alternating pattern of north and south pole magnetic fields emanating from around the perimeter of the rotor  616 . In this configuration, the rotor  616  can behave analogously to a rotor in a brushless direct current (DC) motor configuration. In other examples, the rotor  616  can be configures as a squirrel cage rotor, or any other suitable rotor configuration based on available space, power budget, interference with other device components, and the like. In the squirrel cage configuration, the permanent magnets  628  can be replaced by metal bars that are not permanent magnets. The squirrel cage rotor can behave analogously to a rotor in an induction motor configuration. 
     In some examples, wire coils  624 , which can also be referred to as drive coils, can be arranged at least partially surrounding the rotor  616 . The wire coils  624  can be formed from a large number of closely spaced turns of wire. The wire coils  624  can be connected to coil drivers  622 . The coil drivers  622  and wire coils  624  can form the stator of the haptic feedback configuration. In some examples, the coil drivers  622  can be DC to DC converters that drive currents through the wire coils of the stator. When an electrical current flows through a wire coil, a magnetic field can be formed, with magnetic field lines passing through the center of the coil. The magnetic field lines formed in the wire coils  624  can generate torques by interacting with permanent magnetic fields in the permanent magnets  628  or induced magnetic fields in a squirrel cage rotor. The magnetic field can interact with a net magnetic vector of the rotor  616  to provide a variety of types of haptic feedback as described in the disclosure, such as various rotations or counter-rotations of the rotor  616 , and thus the crown  608 . The magnetic polarity of the field lines generated in wire coils  624  can be dependent on the direction of current flow through each wire coil. The haptic feedback configuration can include controller  630  for controlling the direction and/or amount of current driven through each of the wire coils  624  by the coil drivers  622 . The coil drivers  622  can cause an electric current to flow through one coil at a time, or multiple coils simultaneously in the same or different directions. In some examples, the direction of current flow, and hence the polarity of the magnetic field, can be individually controlled for each wire coil  624  and each coil driver  622 . In some examples, the drive scheme can be implemented as a pre-determined sequence of drive signals, which can in turn provide a pre-determined sequence of torques for rotating the rotor  616 . Utilizing any of the above techniques, the controller can be configured to generate interactions between the magnetic fields generated in the wire coils  624  and the magnetic fields present or induced in the rotor  616  that result in haptic feedback to a user. In some examples, the rotor can correspond to the wheel  316  described above. In other examples, the wheel  316  can correspond to only a portion of the rotor  616 , or the wheel can be included in a separate portion of the crown  608  assembly. The components depicted in  FIG. 6A  can provide rotational and/or resistive forces to the rotor and position sensing that can facilitate providing haptic feedback according to examples of the disclosure. In some examples (not shown), magnets  628  can be embedded within a rotor  616  coupled to and/or included within a rotating bezel as described above. In some examples, wire coils  624  can be arranged to interact with magnets in the rotating bezel to provide rotational and/or resistive forces to the rotor in analogous fashion to one or more of the examples illustrated in  FIG. 6A . 
       FIGS. 6B and 6C  illustrate two of the many possible variations of permanent magnet  628  and wire coil  624  placements that can be used in an implementation of the haptic feedback configuration of  FIG. 6A . While the illustrations of  FIGS. 6B and 6C  depict four permanent magnets embedded within the rotor  616 , a rotor having as few as one permanent magnet or more than four permanent magnets can be used without departing from the scope of this disclosure. Similarly, while  FIGS. 6B and 6C  illustrate five wire coils  624  surrounding the rotor, it is understood that more or fewer wire coils can be used. 
       FIG. 6B  illustrates an exemplary configuration for providing haptic feedback where the permanent magnets  628  extend through the rotor  616  along the direction of the axis of rotation of the rotor according to examples of the disclosure. The permanent magnets  628  can be arranged with alternating polarity of north and south poles. The wire coils  624  can be arranged around the perimeter of the rotor with the coils also extending along the direction of the axis of rotation of the rotor. In this configuration, the magnetic fields induced by driving current through a wire coil  624  can interact with both the north and south magnetic poles of the permanent magnet simultaneously. For simplicity of illustration, no wiring connections or coil drivers (e.g.,  622  in  FIG. 6A ) are shown between the controller  630  and the wire coils  624 . In some examples, the coil drivers  622  and the controller  630  can be integrated into a single drive control circuit for controlling and driving the wire coils  624 . DC power source  631  can be a supply voltage converted by the coil drivers into drive voltages for the wire coils  624 . Sensor  604  can be used to detection the absolute or relative rotation of rotor  616  and can correspond to encoder  204 , optical encoder  304 , mechanical input sensor  528 , or any other position sensor described above. In one example where sensor  604  is an optical encoder, a gap in the wire coils  624  can be provided between the sensor and the rotor  616 , allowing the sensor to detect an encoding pattern that can be included on the rotor (e.g. an encoder wheel) as described above to determine the position of rotor  616 . In some examples, the rotor  616  can be considered a shared driving and sensing segment of a rotary input (e.g., crown  608  and/or a rotating bezel as described above) that can be used for sensing the rotation of the rotary input and for being driven by the stator. The components depicted in  FIG. 6B  can provide rotational and/or resistive forces to the rotor and position sensing that can facilitate providing haptic feedback according to examples of the disclosure. 
       FIG. 6C  illustrates an additional exemplary configuration where the permanent magnets  628  each extend radially outward from the rotation axis to the perimeter of the rotor  616  according to examples of the disclosure. The magnets  628  can be arranged to provide alternating polarity of north and south poles around the perimeter of the rotor  616 . In this configuration, the wire coils  624  can be arranged around the perimeter of the rotor  616  with the coils extending along the radial axis of the rotor. In this configuration, electromagnetic fields induced in the wire coils  624  can interact relatively strongly with the pole of each permanent magnet that is closer to the perimeter of the rotor  616 , while the opposite pole buried within the rotor can have relatively minimal interaction with the electromagnetic fields. Again, for simplicity, no wiring connections or coil drivers (e.g.,  622  in  FIG. 6A ) are shown between the controller  630  and the wire coils  624 . In some examples, the coil drivers and the controller  630  can be integrated into a single drive control circuit for controlling and driving the wire coils  624 . DC power source  631  can be a supply voltage converted by the coil drivers  622  into drive voltages for the wire coils  624 . Sensor  604  can have the same properties as described in connection with  FIG. 6A  above. In one example where sensor  604  is an optical encoder, a gap in the wire coils  624  can be provided between the sensor and the rotor  616 , allowing the sensor to detect an encoding pattern that can be included on the rotor (e.g. an encoder wheel) as described above to determine the position of rotor  616 . The components depicted in  FIG. 6C  can provide rotational and/or resistive forces to the rotor and position sensing that can facilitate providing haptic feedback according to examples of the disclosure. 
       FIGS. 7A-7C  illustrate exemplary control sequences for causing the rotor  716  (which can correspond to rotor  616  above) to rotate or for resisting rotation of the rotor for providing haptic feedback according to examples of the disclosure. In  FIG. 7A , the permanent magnets  728 A- 728 D are aligned in an initial orientation, with south poles of permanent magnets  728 A and  728 C facing toward the rotor  716  surface and located approximately mid-way between successive wire coils  724  (which can correspond to wire coils  624  above). Wire coils  724  can correspond to wire coils  624  and permanent magnets  728 A- 728 D can correspond to permanent magnets  628  described above. To reduce the complexity of  FIGS. 7A-7C , elements from  FIG. 6A  including controller  630  and coil drivers  622  have been omitted and wiring connections between the omitted elements and wire coils  724  have also been omitted. It is understood that the initial alignment state of rotor  716  can correspond to any orientation of the rotor, and the initial state presented in  FIG. 7A  is for illustrative purposes. Alignment of the rotor  716  at any time can be influenced by user interactions with the crown (not shown). On one side of permanent magnet  728 A, current can be driven in a first direction  732  in a first wire coil  724  to establish a south pole near the rotor  716  perimeter, which can repel the south pole of permanent magnet  728 A. On the other side of the magnetic south pole of permanent magnet  728 A, current can be driven in the opposite direction  734  in the wire coil  724  to establish a north pole near the rotor  716 , which can attract the south pole of permanent magnet  728 A. The net force vector formed by the interactions between the permanent magnetic field of magnet  728 A and the induced magnet fields in the wire coils  724  can drive the rotor  716  in the counter-clockwise direction as denoted by direction arrow  735 . The coil drive arrangement can be assisted by a position sensor  704  capable of detecting the rotational position of the rotor  716 . Position sensor  704  can correspond to sensor  604  described above. As described above regarding  FIGS. 6A-6C , the sensor  704  can be an optical position sensor, hall-effect sensor, or any other sensor capable of detecting relative or absolute rotation of the rotor  716 . In some examples, the rotor  716  may include an encoding pattern, such as, for example, a collection of light and dark lines that are arranged in a particular sequence or in a particular pattern. In some examples, the location of at least some of the light lines or the dark lines can be configured to coincide with a position of the permanent magnets. In some examples, the location of the permanent magnets within the rotor  716  can be indicated by a special pattern, such as a thicker white line or dark line. In other examples, the position sensor  704  can be a hall-effect sensor that can detect the magnetic fields emanating from the permanent magnets in order to detect the rotation of the rotor  716 . The position sensor  704  can provide information about the alignment of the permanent magnets  728  relative to the wire coils  724 . This information can aid a controller (e.g. one or more processors, a state machine, etc.) in performing calculations for accurately calculating drive sequences (or drive patterns) that will result in the expected net force vector for providing rotation of rotor  716  with the desired amount of force in the desired direction. The position sensor  704  can be particularly useful when both a user and the magnetic drive configuration are simultaneously acting upon the rotor  716 , since a controller can potentially be capable of predicting the amount of motion due to the magnetic drive, but would not be able to reliably predict an arbitrary user input. 
     In some examples where limited space may be available for a haptic feedback system, one wire coil  724  can be omitted between the position sensor  704  and the rotor  716 . In this example, the rotor  716  can include the encoder pattern described above (e.g., to perform the function of wheel  316 ) while also performing the rotor  716  function (e.g., rotating in response to a force) in the haptic feedback system. By integrating two separate functions into the rotor  716 , space can be conserved relative to providing separate hardware components for a rotor  716  and an encoder wheel (e.g., wheel  316 ). In some examples, the drive sequences applied to the wire coils  724  can be modified to compensate for the omitted wire coil  724 . 
       FIG. 7B  shows the rotor  716  at a second point in time, after being driven by the first field configuration and experiencing rotation along direction  735 . As shown, south poles of permanent magnets  728 A and  728 C can become approximately aligned with the centers of the nearest respective wire coils  724 . At the same time, north poles of permanent magnets  728 B and  728 D can be slightly out of alignment with the nearest respective wire coils. In this example, currents in a first direction  732  can be driven in to two wire coils  724 , establishing magnetic south poles near the rotor  716  and attracting north poles  728 B and  728 D. In this configuration, the net force vector formed by the interaction between the permanent magnetic field of the magnets  728 B and  728 D with magnetic fields in the driven coils  724  can move the rotor  716  in the counter-clockwise direction as denoted by direction arrow  735 . It should be noted that the example of  FIG. 7A  utilizes both attracting and repelling forces while the example in  FIG. 7B  utilizes two attracting forces to drive the rotor  716  in the same, counter-clockwise direction. A continuous rotation can be achieved by sequentially varying the driven wire coil(s)  724  and direction(s) of current to drive the rotor  716 . Alternatively, the coil drive sequence can be used to provide a small counter rotation to an externally applied rotation input, for example a rotation input from a user. The position sensor  704  can perform similar functions as described above regarding  FIG. 7A . 
     It should be understood that simultaneously driving multiple wire coils is not required to generate rotation of the rotor. However, a rotation driven by multiple wire coils  724  can be used to generate a greater amount of torque in the rotor  716 . The particular selection of the rotation drive scheme can vary based on the space available for multiple coils in the stator, limitations of the rotor such as the number of magnets, the power budget available for providing haptic feedback, and the like. 
       FIG. 7C  illustrates a configuration for resisting rotation of the rotor  716  to provide different types of haptic feedback. The position of the rotor  716  depicted in  FIG. 7C  can be identical to the initial position of the rotor described in  FIG. 7B . However, the controller (e.g.,  630  in  FIG. 6A ) can be used to provide different drive signals on the wire coils  724  to produce a different result. In this configuration, the two wire coils  724  nearest permanent magnets  728 A and  728 C can be driven with currents in direction  734  to provide a relatively strong attractive force with south poles of permanent magnets  728 A and  728 C, which can be well-aligned with the centers of the adjacent wire coils  724 . The magnetic fields generated in the wire coils  724  can have the greatest magnitude along the central axis of the coils, thus providing a strong attraction between the induced magnetic field and the permanent magnetic fields in the rotor  716 . Depending on the strength of the magnetic attraction, this drive configuration can give a user the sensation of a small resistance to turning, or can provide a large resistance that is difficult for the user to overcome. The position sensor  704  can perform similar functions as described above regarding  FIG. 7A . 
       FIG. 8  illustrates an additional example of a piezoelectric haptic feedback configuration for providing haptic feedback according to examples of the disclosure.  FIG. 8  depicts an exemplary cross-section through the center of a shaft  826  which can connect crown  808  with encoder wheel  816  (which can correspond to wheel  316  above). The shaft  826  can pass through an opening in housing  838  of the electronic device (which can correspond to device  100  or  500  above). Housing  838  can be attached to a mount  840  and the shaft  826  can pass through the center of the mount. A rotor disc  836  can be fixed to the shaft  826 , and the disc can be sized to fit within a central cavity of the mount  840 . The rotor disc  836  can rotate axially around a central axis  842  of the shaft  826  and can also move in either direction (e.g. in and out) along the rotation axis  842  of the shaft  826 . The rotor disc  836  can be moved along with the shaft when user input is applied to the crown  808 . In some examples, the rotor disc  836  can be incorporated within and/or coupled to a rotating bezel as described above. In addition, a piezoelectric wave motor can be used to induce motion in the rotor disc  836 . The piezoelectric wave motor can include a stator disc  822  and a piezoelectric disc made up of piezoelectric elements  834 . The stator disc  822  can include electrodes used to drive an electric potential (e.g. a voltage) onto one or more of the piezoelectric elements  834 . Piezoelectric elements  834  can include one or more piezoelectric layers. Upon application of the electric potential to piezoelectric elements  834 , the piezoelectric layers in individual piezoelectric elements  834  can expand or contract, causing some or all of the piezoelectric elements  834  to contact the rotor disc  836 . The expansions and contractions of individual elements can be controlled by a controller attached to the stator, and this controller can be used to generate rotation of the shaft  826  and/or rotating bezel or to resist rotation of the shaft and/or rotating bezel as desired, as will be described in more detail below. Spring  832  can be included behind the stator disc  822  within the central cavity of mount  840  to provide a backing force to the stator disc. In some examples, when a user presses the rotor disc against the stator disc, the stator disc can flex, and the spring  832  can compress while providing the backing force to the stator disc. In another example, the mount  840  can provide the backing force for the stator disc  822 . However, since the stator disc  822  may include electrodes on its surface, it can be important that the mount  840  or the spring  832  does not create electrical contacts between the electrodes that are potentially exposed. In some examples, compression of spring  832  can be used to detect a translational input on the crown  808 . For example, compression of spring  832  can activate a switch, and in some examples, the spring can be a component of the switch. 
       FIGS. 9A-9D  illustrate various examples of piezoelectric element  934  activation for controlling motion of the rotor disc  936  (which can correspond to rotor disc  836  above) for providing haptic feedback according to examples of the disclosure.  FIG. 9A  illustrates a condition where the piezoelectric elements  934  (which can correspond to piezoelectric elements  834  above) are driven by electrodes on stator disc  922  (which can correspond to stator disc  822  above) such that the piezoelectric elements are all in a contracted position. In this condition, the rotor disc  936  can be allowed to freely rotate within the cavity of the mount  940  (which can correspond to mount  840  above), for example the rotor disc  936  can freely rotate when a user provides a mechanical force to the crown  908  (which can correspond to crown  808  above), causing the shaft  926  (which can correspond to shaft  926  above) to rotate. 
       FIGS. 9B and 9C  depict examples of piezoelectric element  934  activation for generating a rotational movement of the rotor disc  936  for providing haptic feedback according to examples of the disclosure. For simplicity of illustration, the stator disc  922  is omitted from the illustrations. It should be recognized that appropriate electrical connections must be provided for application of drive signals for piezoelectric element  934  activation. By controlling the voltage applied to individual piezoelectric elements  934  selectively causing some elements to expand, and some elements to contract, a travelling wave can be established at the piezoelectric elements. Piezoelectric elements  934  at the peak of the travelling wave can contact the rotor disc  936 , and through friction between the piezoelectric elements and the rotor disc, the piezoelectric elements can apply a rotational force to the rotor disc. The peaks of the piezoelectric elements  934  can be controlled to generate a travelling wave in direction  946 . With each element successively generating a small amount of frictional force against the rotor disc  936 , the travelling wave can generate a rotor disc rotation in the opposite direction  948 . Typically, the rate of rotation of the rotor disc  936  in direction  948  can be slower than the rate of propagation of the travelling wave in the direction  946 . The rate of rotation of the rotor disc  936  can depend at least in part on the force of the contact between the piezoelectric elements  934  and the rotor disc. As a result, for a particular traveling wave velocity in direction  946 , the rotor disc  936  may rotate at different rates in direction  948  depending on the relative orientation of the mount  940  and rotor disc due to the effects of gravity (e.g., when a device containing the piezoelectric haptic feedback configuration is turned on its side). Accordingly, different traveling wave velocities can be applied for different orientations of a device to achieve a constant rotation velocity for every orientation. The forces provided by the piezoelectric elements described above can be used to provide haptic feedback according to examples of the disclosure. 
       FIG. 9C  illustrates that by changing the control sequence of voltage applied to the piezoelectric elements  934  the travelling wave direction  946  can be reversed, thus causing rotor disc  936  rotation in the opposite direction  948  from  FIG. 9B . While the examples of  FIGS. 9B and 9C  depict piezoelectric elements  934  directly contacting the rotor disc  936 , it should be noted that alternative configurations would be acceptable as long as sufficient force can be transferred from the traveling wave into the rotor disc. For example, an interface layer (not shown) can be placed between the piezoelectric elements  934  and the rotor disc  936 . In some examples, the interface layer can be made of an insulating material, such as elastic. A suitable material can provide adequate friction with the rotor disc  936  for efficient energy transfer, while protecting the surfaces of the piezo electric elements  934  and the rotor disc. The insulating material can also allow for the use of an electrically conductive rotor disc  936  by preventing contact between the piezo electric elements  934  or stator electrodes (not shown) and metal in the housing or the rotor disc. 
       FIG. 9D  illustrates a piezoelectric element  934  activation condition for resisting rotation of the rotor disc  936  according to examples of the disclosure. By statically applying a voltage to some or all of the piezoelectric elements  934 , the rotor disc  936  can be pressed against the mount  940  such that a large frictional force can be created. The greater the amount of force provided by the piezoelectric elements  934 , the more resistance a user can experience while trying to rotate the crown (not shown). Thus, this configuration can be used either to slow rotation relative to the free rotation illustrated in  FIG. 9A , or with sufficient force can prevent rotation of the crown by the user entirely. In practice, the amount of force applied to the rotor disc  936  could be limited to remain under a maximum force threshold to prevent damage to the device due to attempts by a user to overcome the applied resistance. The resistance to rotation described above is another type of force that can be used to provide haptic feedback according to examples of the disclosure. 
       FIG. 10  depicts an exemplary process  1000  for providing haptic feedback according to examples of the disclosure. It should be noted that any of the example actuator configurations described above, or any number of variations of or alternatives to the actuator configurations described above that are capable of controllably generating motion of a shaft, rotor, or the like could be suitable for implementing process  1000 . At step  1002 , process  1000  can receive crown (e.g. crown  108 ) position information, such as an amount and a direction of rotation. In some examples, the received crown position information can correspond to an amount of crown rotation performed by a user. At step  1004 , process  1000  can determine if haptic feedback is desired in one or more of the manners described in this disclosure. In some examples it can be determined that a haptic feedback is desired when an input is received based on a state of a display (e.g. when display  206  shows a cursor at the end of a scrollable list as described above). In other examples, it can be determined that haptic feedback is desired when a specific type, direction and/or amount of movement is detected by a position sensor (e.g. 30 degrees of rotation of crown  508  detected in a particular direction by mechanical input sensor  528  as described above). At step  1006 , haptic feedback can be induced in the crown, which can be felt by a user, in one or more of the manners described in this disclosure. In some examples, the haptic feedback can simulate the “click-click-click” of a mechanical watch according to examples of the disclosure. In other examples, the haptic feedback can be used to assist rotation or resist rotation of a crown according to examples of the disclosure. Once step  1006  is completed and haptic feedback is applied, the process  1000  can return to step  1002 . In some examples, if at step  1004  it is detected that haptic feedback is not desired, the process  1000  can return to step  1002 . 
       FIG. 11  depicts an exemplary process  1100  for performing finger-on-crown detection according to examples of the disclosure. It should be noted that any of the example actuator configurations described above, or any number of variations of or alternatives to the actuator configurations described above that are capable of controllably inducing a micro-tremor in a rotary input, could be suitable for implementing process  1100 . At step  1102 , process  1100  can induce a micro-tremor in a rotary input (e.g. a shaft), which can in turn induce the micro-tremor in a crown coupled to the shaft. At step  1104 , process  1100  can receive crown position information (e.g. from mechanical input sensor  528 , or other position sensors described above), such as an amount and a direction of rotation of the crown. The received crown position information can correspond to a characteristic data pattern consistent with the movement of the crown induced in the crown by the micro-tremor when the crown is not in contact with a user or otherwise experiencing resistance to rotation. However, contact with the crown by an object or a user can interfere with the crown&#39;s motion, and alter the received crown position information such that it deviates from the characteristic data pattern. At step  1106 , process  1100  can determine whether the received crown information is consistent with the characteristic data pattern induced by the micro-tremor. If it is determined that the received crown position information deviates from the characteristic data pattern, process  1100  can proceed to step  1108 . In some examples, process  1100  can proceed to step  1108  only when an amount of deviation from the characteristic data pattern exceeds a threshold amount of deviation (e.g., a deviation of 25%). At step  1108 , process  1100  can determine whether the detected deviation is consistent with a finger in contact with the crown. For example, if the detected deviation is consistent with an oscillation at a natural human oscillation frequency interacting with the micro-tremor, the process  1100  can proceed to step  1110 . It should be recognized that many types of deviations may be detected at step  1106 , and that an assessment of whether a deviation is consistent with a finger in contact with the crown can potentially be determined from a variety of different types of deviation (e.g., constructive interference, destructive interference, or resonance described above). A person of ordinary skill in the art will understand that such variations are within the scope of the disclosure. At step  1110 , the process  1100  can indicate a finger-on-crown condition, and then process  1100  can return to step  1102 . If at step  1106  it is determined that the received crown position information does not deviate from the characteristic data pattern, the process  1100  can return to step  1102 . If at step  1108  it is determined that the detected deviation is not consistent with a finger in contact with the crown, the process  1100  can return to step  1102 . In some examples, there may be a deviation from a characteristic data pattern of the micro-tremor that does not indicate a finger-on-crown condition. In some examples, if the deviation does not indicate a finger-on-crown condition, step  1108  can indicate that a deviation occurred that was not consistent with a finger-on-crown condition, and then process  1100  can return to step  1102 . 
     In some examples, step  1102  can be omitted (e.g., to perform non-assisted finger-on-crown detection, as described above with reference to  FIG. 5C ), and process  1100  can begin at step  1104 . At step  1104 , process  1100  can receive crown position information, such as an amount and a direction of rotation. In this example, the characteristic data pattern could be considered to be a pattern of received crown position information indicative of no movement. Thus, any detected rotation can be a deviation from the expected movement. In some examples, steps  1106  and  1108  can be combined such that any detected rotation can be analyzed to determine whether the detected rotation is consistent with a finger-on-crown condition. 
       FIG. 12  illustrates an example computing system  1200  for implementing haptic feedback according to examples of the disclosure. Computing system  1200  can be included in, for example, device  100  above or any mobile or non-mobile computing device and/or wearable or non-wearable device that includes a rotary input (e.g., rotary input  508  described above). Computing system  1200  can include a touch sensing system including one or more touch processors  1202 , touch controller  1206  and touch screen  1204 . Touch screen  1204  can be a touch screen adapted to sense touch inputs, as described in the disclosure. Touch controller  1206  can include circuitry and/or logic configured to sense touch inputs on touch screen  1204 . In some examples, touch controller  1206  and touch processor  1202  can be integrated into a single application specific integrated circuit (ASIC). 
     Computing system  1200  can also include host processor  1228  for receiving outputs from touch processor  1202  and performing actions based on the outputs. Host processor  1228  can be connected to program storage  1232 . For example, host processor  1228  can contribute to generating an image on touch screen  1204  (e.g., by controlling a display controller to display an image of a user interface (UI) on the touch screen), and can use touch processor  1202  and touch controller  1206  to detect one or more touches on or near touch screen  1204 . Host processor  1228  can also contribute to sensing and/or processing mechanical inputs  1208  (which can correspond to rotary input  508  described above), and controlling mechanical input actuator  1210  (which can correspond to mechanical input actuator  530  above), as described in the disclosure. The inputs from touch screen  1204  and/or mechanical inputs  1208  can be used by computer programs stored in program storage  1232  to perform actions in response to the touch and/or mechanical inputs. For example, touch inputs can be used by computer programs stored in program storage  1232  to perform actions that can include moving an object such as a cursor or pointer, scrolling or panning, adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device connected to the host device, answering a telephone call, placing a telephone call, and other actions that can be performed in response to touch inputs. Mechanical inputs  1208  can be used by computer programs stored in program storage  1232  to perform actions that can include changing a volume level, locking the touch screen, turning on the touch screen, taking a picture, and other actions that can be performed in response to mechanical inputs. Host processor  1228  can cause rotation of mechanical inputs  1208  by mechanical input actuator  1210  (which can correspond to mechanical input actuator  530 ) based on the mechanical inputs and/or the context of computing system  1200  (e.g., what application(s) are running on the computing system, what user interface(s) are displayed by the computing system, etc.), as previously described. Host processor  1228  can also perform additional functions that may not be related to touch and/or mechanical input processing. 
     Note that one or more of the functions described above can be performed by firmware stored in memory in computing system  1200  and executed by touch processor  1202 , or stored in program storage  1232  and executed by host processor  1228 . The firmware can also be stored and/or transported within any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer-readable storage medium” can be any medium (excluding signals) that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The firmware can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     Therefore, according to the above, some examples of the disclosure are directed to an electronic device comprising: a mechanical input configured to rotate in a first direction about a rotation axis in response to a first input at the mechanical input; a mechanical input sensor coupled to the mechanical input and configured to sense a rotation of the mechanical input about the rotation axis; and a mechanical input actuator coupled to the mechanical input and configured to rotate the mechanical input in a second direction about the rotation axis. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input comprises a shared driving and sensing segment, the mechanical input sensor is configured to sense the rotation of the mechanical input at the shared driving and sensing segment, and the mechanical input actuator is configured to generate magnetic fields for rotating the mechanical input at the shared driving and sensing segment. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the shared driving and sensing segment includes at least one magnet. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input actuator includes a gap, wherein sensing the rotation of the mechanical input at the shared driving and sensing segment occurs through the gap. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the gap included in the mechanical input actuator is a gap in a drive coil arrangement disposed around the shared driving and sensing segment. Additionally or alternatively to one or more of the examples disclosed above, in some examples, a drive pattern for generating magnetic fields in the electromagnetic drive coil arrangement is configured to provide a first drive sequence when a first portion of the shared driving and sensing element is located near the drive coil arrangement, and to provide a second drive sequence when the first portion of the shared driving and sensing element is located near the gap. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first portion of the shared driving and sensing element corresponds to a location a magnet included in the shared driving and sensing element. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input sensor comprises an optical sensor configured to sense the rotation of the mechanical input by sensing movement of a pattern disposed on the shared driving and sensing element through the gap, and at least a portion of the pattern disposed on the shared driving and sensing element corresponds to a location of a magnet included in the shared driving and sensing element. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input is further configured to translate along the rotation axis in response to a second input, and the mechanical input actuator comprises at least one piezoelectric element configured to: allow the mechanical input to translate along the rotation axis, and rotate the mechanical input in the second direction about the rotation axis. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input actuator is further configured to deflect in response to the second input to allow for activation of a translational input. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the at least one piezoelectric element is coupled to a stator disc configured for providing a voltage to the at least one piezeoelectric element, the stator disc is coupled to a housing of the electronic device, and the mechanical input comprises a rotor disc coupled to a shaft and the shaft is configured to pass through an opening in the housing of the electronic device. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the at least one piezoelectric element resists rotation of the mechanical input about the rotation axis by increasing an amount of friction acting against rotation of the mechanical input about the rotation axis. 
     Some examples of the disclosure are directed to a non-transitory computer readable storage medium having stored thereon a set of instructions, that when executed by a processor causes the processor to: sense a rotation of a mechanical input in a first direction about a rotation axis resulting from an input at the mechanical input; and rotate the mechanical input in a second direction about the rotation axis. Additionally or alternatively to one or more of the examples disclosed above, in some examples, sensing the rotation of the mechanical input comprises sensing the rotation of the mechanical input about the rotation axis at a shared driving and sensing segment of the mechanical input; and rotating the mechanical input in the second direction about the rotation axis comprises generating magnetic fields at the shared driving and sensing segment for rotating the mechanical input. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the mechanical input is configured to translate along the rotation axis in response to a second input, and the instructions further cause the processor to: rotate the mechanical input in the second direction about the rotation axis using at least one piezoelectric element, the at least one piezoelectric element configured to allow the mechanical input to translate along the rotation axis. 
     Some examples of the disclosure are directed to a method comprising the steps of: sensing a rotation of a mechanical input in a first direction about a rotation axis resulting from an input at the mechanical input, and rotating the mechanical input in a second direction about the rotation axis. Additionally or alternatively to one or more of the examples disclosed above, in some examples, sensing the rotation of the mechanical input comprises sensing the rotation of the mechanical input about the rotation axis at a shared driving and sensing segment of the mechanical input; and rotating the mechanical input in the second direction about the rotation axis comprises generating magnetic fields at the shared driving and sensing segment for rotating the mechanical input. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method further comprises rotating the mechanical input in the second direction about the rotation axis using at least one piezoelectric element, the at least one piezoelectric element configured to allow the mechanical input to translate along the rotation axis, wherein the mechanical input is configured to translate along the rotation axis in response to a second input. 
     Some examples of the disclosure are directed to an electronic device comprising: a mechanical input configured to receive input from a user and move in a first direction; a mechanical input sensor coupled to the mechanical input and configured to sense a movement of the mechanical input in the first direction; and a processor capable of determining whether the sensed movement of the mechanical input is consistent with the user contacting the mechanical input without identifying the sensed movement as a user input to the electronic device. Additionally or alternatively to one or more of the examples disclosed above, in some examples, determining whether the sensed movement is consistent with the user contacting the mechanical input comprises determining whether the sensed movement corresponds to a micro-tremor of a finger. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the electronic device further comprises a mechanical input actuator coupled to the mechanical input and configured to provide a micro-oscillation to the mechanical input. Additionally or alternatively to one or more of the examples disclosed above, in some examples, determining whether the sensed movement is consistent with the user contacting the mechanical input comprises detecting an interaction between the micro-oscillation and a micro-tremor of a finger. 
     Although examples of this disclosure have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of examples of this disclosure as defined by the appended claims.

Metadata:
Filing Date: 20150930
Publication Date: 20180515
Grant Date: 20180515
Priority Date: 20150930
Inventors: HOLENARSIPUR, PRASHANTH
WANG, ALBERT
KUBOYAMA, YUTA
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0362", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 58409202