PATENT DOCUMENT

Publication Number: US-10622538-B2
Application Number: US-201715653468-A
Country: US
Kind Code: B2

Title: Techniques for providing a haptic output and sensing a haptic input using a piezoelectric body

Abstract:
Haptic interfaces are described. One haptic interface includes a piezoelectric body and first and second electrodes coupled to the piezoelectric body. The haptic interface also includes a control circuit. The control circuit includes a haptic actuator, a haptic sensor circuit, and an overcurrent protection circuit. The haptic actuator circuit is coupled to the first electrode and configured to charge the piezoelectric body. The charging causes the piezoelectric body to provide a haptic output. The haptic sensor circuit is coupled to the second electrode and configured to sense an electrical change at the second electrode. The electrical change is related to a haptic input received by the piezoelectric body. The overcurrent protection circuit is coupled to the second electrode and configured to limit a current flow into the haptic sensor circuit while the haptic actuator circuit is charging the piezoelectric body.

Claims:
What is claimed is: 
     
       1. A haptic interface, comprising:
 a piezoelectric body; 
 a first electrode coupled to the piezoelectric body; 
 a second electrode coupled to the piezoelectric body; and 
 a control circuit, comprising:
 a haptic actuator circuit coupled to the first electrode and configured to charge the piezoelectric body, the charging causing the piezoelectric body to provide a haptic output; 
 a haptic sensor circuit coupled to the second electrode and configured to sense an electrical change at the second electrode, the electrical change related to a haptic input received by the piezoelectric body; and 
 an overcurrent protection circuit coupled to the second electrode and configured to limit a current flow into the haptic sensor circuit while the haptic actuator circuit is charging the piezoelectric body. 
 
 
     
     
       2. The haptic interface of  claim 1 , wherein the overcurrent protection circuit comprises:
 a transistor coupled between the second electrode and a discharge node, the transistor having a control input configured to receive a signal that causes the transistor to open or close a current path between the second electrode and the discharge node. 
 
     
     
       3. The haptic interface of  claim 1 , wherein the overcurrent protection circuit comprises:
 a clamper circuit coupled between the second electrode and a discharge node. 
 
     
     
       4. The haptic interface of  claim 3 , wherein the clamper circuit comprises a forward-biased diode coupled in parallel with a reverse-biased diode. 
     
     
       5. The haptic interface of  claim 1 , wherein the haptic sensor circuit comprises a sense amp, the sense amp comprising a negative input coupled to the second electrode and a positive input coupled to a discharge node. 
     
     
       6. The haptic interface of  claim 5 , wherein the overcurrent protection circuit is coupled between the negative input and the positive input of the sense amp, and the positive input of the sense amp is coupled to the discharge node. 
     
     
       7. The haptic interface of  claim 5 , wherein the overcurrent protection circuit comprises:
 a transistor coupled between the negative input and the positive input of the sense amp, the transistor having a control input configured to receive a control signal that causes the transistor to open or close a current path between the negative input and the positive input of the sense amp, 
 wherein the positive input of the sense amp is further coupled to the discharge node. 
 
     
     
       8. The haptic interface of  claim 7 , wherein the haptic actuator circuit comprises:
 a second transistor coupled between the first electrode and a power source, the second transistor having a second control input configured to receive a second control signal that causes the second transistor to open or close a second current path between the first electrode and the power source; and 
 a third transistor coupled between the first electrode and the discharge node, the transistor having a third control input configured to receive a third control signal that causes the third transistor to open or close a third current path between the first electrode and the discharge node. 
 
     
     
       9. The haptic interface of  claim 5 , wherein the overcurrent protection circuit comprises:
 a charge integration capacitor coupled between the negative input of the sense amp and an output of the sense amp. 
 
     
     
       10. The haptic interface of  claim 9 , further comprising:
 an integrated charge discharge circuit coupled to the charge integration capacitor, the integrated charge discharge circuit having a control input configured to receive a control signal that causes the integrated charge discharge circuit to discharge a charge integrated by the charge integration capacitor. 
 
     
     
       11. The haptic interface of  claim 5 , further comprising:
 a digital sampling circuit coupled to an output of the sense amp. 
 
     
     
       12. A haptic interface, comprising:
 a piezoelectric body; 
 a first electrode coupled to the piezoelectric body; 
 a second electrode coupled to the piezoelectric body; and 
 a control circuit, comprising:
 a haptic actuator circuit coupled to the first electrode and configured to maintain a charge on the piezoelectric body, the charge causing the piezoelectric body to provide a haptic output; and 
 a haptic sensor circuit coupled to the second electrode and configured to sense an electrical change at the second electrode while the piezoelectric body is charged, the electrical change related to a haptic input received by the piezoelectric body. 
 
 
     
     
       13. A method of operating a haptic interface, comprising:
 charging a piezoelectric body of the haptic interface to deliver a haptic output; 
 limiting a current flow into a haptic sensor circuit while charging the piezoelectric body; and 
 monitoring for a haptic input to the piezoelectric body using the haptic sensor circuit while the piezoelectric body is charged; 
 wherein limiting the current flow into the haptic sensor circuit comprises diverting at least a portion of the current flow from into the haptic sensor circuit to a discharge node. 
 
     
     
       14. The method of  claim 13 , further comprising:
 monitoring for the haptic input while charging the piezoelectric body. 
 
     
     
       15. The method of  claim 13 , wherein diverting at least the portion of the current flow from into the haptic sensor circuit to the discharge node comprises:
 applying a control signal to a transistor. 
 
     
     
       16. The method of  claim 15 , wherein the transistor is coupled between a first input and a second input of the haptic sensor circuit. 
     
     
       17. The method of  claim 16 , wherein the first input is coupled to an electrode attached to the piezoelectric body, and the second input is coupled to the discharge node. 
     
     
       18. The method of  claim 13 , wherein diverting at least the portion of the current flow from into the haptic sensor circuit to the discharge node comprises:
 automatically diverting at least the portion of the current flow based on a parameter of a diode.

Description:
FIELD 
     The present disclosure generally relates to haptic interfaces, and to techniques for providing a haptic output and sensing a haptic input using a piezoelectric body. The haptic output may be provided by actuating the piezoelectric body. 
     BACKGROUND 
     Electronic devices are commonplace in today&#39;s society. Some electronic devices incorporate a haptic interface (e.g., a haptic input or output system). An electronic device with a haptic interface may activate the haptic interface to solicit a user&#39;s attention, enhance the user&#39;s interaction experience with the electronic device, displace the electronic device or a component of the electronic device, or provide any other suitable notification or user experience. An electronic device with a haptic interface may also, or alternatively, receive a force input from a user via the haptic interface, and in response to the force input, wake up a portion of the electronic device, manipulate a graphical element on a display of the electronic device, or perform another operation in response to the force input. 
     Piezoelectric materials can convert between mechanical energy and electrical energy. A piezoelectric material (or piezoelectric body) may be used to convert mechanical energy into electrical energy using what has been referred to as the direct piezoelectric effect. Conversion of mechanical energy into electrical energy can be used to sense a mechanical force or pressure on, or displacement of, a piezoelectric body. A piezoelectric body may also, or alternatively, convert electrical energy into mechanical energy using what has been referred to as the inverse piezoelectric effect. Conversion of electrical energy into mechanical energy can be used to actuate a piezoelectric body and, in some cases, move or displace the piezoelectric body. 
     One application for piezoelectric bodies is in haptic interfaces of electronic devices. The direct piezoelectric effect can be used to sense a haptic input to the haptic interface (e.g., a user&#39;s force or pressure on, or displacement of, a piezoelectric body included in a haptic interface). The inverse piezoelectric effect can be used to provide a haptic output via the haptic interface (e.g., a piezoelectric body may be electrically charged to cause the piezoelectric body to produce a force, pressure, or displacement that can be perceived by a user of the haptic interface). 
     SUMMARY 
     The present disclosure is directed to haptic interfaces, and to techniques for providing a haptic output and sensing a haptic input using a piezoelectric body. In particular, the present disclosure describes a control circuit for a piezoelectric body of a haptic interface. The control circuit may be used to both actuate the piezoelectric body, to provide a haptic output, and to sense an electrical change corresponding to a haptic input received by the piezoelectric body. In some embodiments, a piezoelectric body may be simultaneously actuated and sensed. In some embodiments, the control circuit may include an overcurrent protection circuit that limits current flow into a sensing portion of the control circuit while an actuation portion of the control circuit is charging the piezoelectric body. The overcurrent protection circuit may be needed because a haptic actuation signal provided by the actuation portion of the control circuit may be sensed by the sensing portion of the control circuit, and may be one or more orders of magnitude greater than a haptic input signal intended to be sensed by the sensing portion of the control circuit. The haptic actuation signal could therefore damage the sensing portion of the control circuit in the absence of an overcurrent protection circuit. 
     In a first aspect of the present disclosure, a haptic interface is described. The haptic interface may include a piezoelectric body and first and second electrodes coupled to the piezoelectric body. The haptic interface may also include a control circuit. The control circuit may include a haptic actuator circuit, a haptic sensor circuit, and an overcurrent protection circuit. The haptic actuator circuit may be coupled to the first electrode and configured to charge the piezoelectric body. The charging may cause the piezoelectric body to provide a haptic output. The haptic sensor circuit may be coupled to the second electrode and configured to sense an electrical change at the second electrode. The electrical change may be related to a haptic input received by the piezoelectric body. The overcurrent protection circuit may be coupled to the second electrode and configured to limit a current flow into the haptic sensor circuit while the haptic actuator circuit is charging the piezoelectric body. 
     In another aspect of the present disclosure, another haptic interface is described. The haptic interface may include a piezoelectric body and first and second electrodes coupled to the piezoelectric body. The haptic interface may also include a control circuit. The control circuit may include a haptic actuator circuit, a haptic sensor circuit, and an overcurrent protection circuit. The haptic actuator circuit may be coupled to the first electrode and configured to maintain a charge on the piezoelectric body. The charge may cause the piezoelectric body to provide a haptic output. The haptic sensor circuit may be coupled to the second electrode and configured to sense an electrical change at the second electrode while the piezoelectric body is charged. The electrical change may be related to a haptic input received by the piezoelectric body. 
     In yet another aspect of the present disclosure, a method of operating a haptic interface is described. The method may include charging a piezoelectric body of the haptic interface to deliver a haptic output, limiting a current flow into a haptic sensor circuit while charging the piezoelectric body, and monitoring for a haptic input to the piezoelectric body using the haptic sensor circuit while the piezoelectric body is charged. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  shows a front view of an electronic device incorporating a sample haptic interface; 
         FIGS. 2A and 2B  show a first anchoring configuration that may be used for a piezoelectric body of a haptic interface; 
         FIGS. 3A and 3B  show a second anchoring configuration that may be used for a piezoelectric body of a haptic interface; 
         FIGS. 4A and 4B  show a third anchoring configuration that may be used for a piezoelectric body of a haptic interface; 
         FIGS. 5A, 5B, and 5C  show sample constructions of a piezoelectric body that may be used in a haptic interface; 
         FIG. 6  shows a cross-section of a piezoelectric body attached to first and second electrodes; 
         FIG. 7  shows a block diagram of a haptic interface capable of providing a haptic output and sensing a haptic input; 
         FIG. 8  shows a sample first circuit schematic for a haptic interface; 
         FIG. 9  shows a graph of voltage at the second electrode, over time, for various charging scenarios of the piezoelectric body shown in  FIG. 8 ; 
         FIG. 10  shows a sample second circuit schematic for a haptic interface; 
         FIG. 11  shows a sample third circuit schematic for a haptic interface; 
         FIG. 12  shows a sample fourth circuit schematic for a haptic interface; 
         FIG. 13  shows a graph of voltage at the second electrode, over time, for various charging scenarios of the piezoelectric body shown in  FIG. 12 ; 
         FIGS. 14 and 15  show electronic devices that may incorporate haptic interfaces; 
         FIGS. 16 and 17  show methods of operating a haptic interface; and 
         FIG. 18  shows a sample electrical block diagram of an electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the description to a preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents to the described embodiments, as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     The embodiments described herein are directed to a haptic interface that receives and provides localized haptic inputs and output for an electronic device. The haptic interface may include a set of piezoelectric bodies (e.g., synthetic ceramic bodies (e.g., lead zirconate titanate (PZT) bodies), lead-free piezoceramic bodies (e.g., sodium potassium niobate bodies), natural crystal bodies (e.g., quartz bodies, synthetic crystal bodies, and so on), and may provide or be coupled to a surface such as, for example, a cover glass or display of the electronic device. When a piezoelectric body of the haptic interface is compressed, deflected, deformed, or otherwise moved by a haptic input (e.g., by a user or structure, such as a user intending to press a key of a keyboard or a button), the compression, deflection, deformation, or other movement may be measured, and a signal corresponding to the compression, deflection, deformation, or other movement may be received by a processor of the electronic device. In some cases, the processor may wake up a portion of the electronic device, manipulate a graphical element on a display of the electronic device, clear a notification, stop a timer, or perform another operation in response to the signal. The processor may also activate the haptic interface (e.g., by generating an electric field that causes one or more piezoelectric bodies to compress, deflect, deform, rapidly change shape (e.g., vibrate), or otherwise physically change) to solicit a user&#39;s attention, enhance the user&#39;s interaction experience with the electronic device, displace the electronic device or a component of the electronic device, or provide any other suitable notification or user experience. 
     In some examples, a compression, deflection, deformation, or other movement of a piezoelectric body may cause a change in voltage between electrodes attached to the piezoelectric body. Conversely, a processor may apply an electric current or voltage to the electrodes to cause the piezoelectric body to compress, deflect, deform, vibrate, or otherwise move. 
     In some implementations, the size, change, state, or rate of change in a piezoelectric body may be related to the amount of compression, deflection, deformation, or movement of the haptic interface and, as a result, the magnitude or strength of haptic input or output. Thus, the greater the change in compression, deflection, deformation, or other movement of a piezoelectric body, the greater the haptic input (e.g., force input) or haptic output (e.g., force output). 
     A panel-sized vibration actuator (e.g., for display panel haptic applications) can be constructed with multiple piezoelectric bodies assembled on a flex circuit or sandwiched between flex circuits. In such an architecture, two electrodes may be positioned on opposite faces of each piezoelectric body. For example, a top electrode can be formed on a top face of a piezoelectric body and a bottom electrode can be formed on a bottom face of the piezoelectric body. In some cases, the bottom electrode can wrap around a sidewall of the piezoelectric body. In such a configuration, the top electrode and the bottom electrode may both occupy a portion of the top face of the piezoelectric body. 
     A set of piezoelectric bodies, each with corresponding electrodes, may be sandwiched between first and second substrates, such as first and second flex circuits, or a flex circuit and a stiffener. Each piezoelectric body may be electrically connected to the first or second substrate. For example, a first electrical connection can be made between a top electrode of a piezoelectric body and an electrical conductor on or within a top flex circuit, and a second electrical connection can be made between a bottom electrode of the piezoelectric body and an electrical conductor on or within a bottom flex circuit. 
     The first and second electrical connections can be established using any number of suitable techniques including, but not limited to, soldering, welding, bonding with a conductive adhesive, bonding with a conductive tape, placing conductive surfaces in contact, and so on. 
     In some use cases, it may be useful to sense a haptic input while providing a haptic output. In some cases, a haptic input and haptic output may be sensed/provided by different piezoelectric bodies and respective control circuits, because haptic actuation signals may be orders of magnitude greater than haptic input signals (e.g., milliamps versus nano-Coulombs), making piezoelectric actuation and sensing circuits incompatible. In other cases, and as described in the present disclosure, piezoelectric actuation and sensing circuits may be used in conjunction with a single piezoelectric body (or single set of piezoelectric bodies) by using an overcurrent protection circuit to protect the sensing circuit during time periods when the charging of a piezoelectric body may damage the sensing circuit. When piezoelectric actuation and sensing circuits are combined, haptic input to a piezoelectric body may be sensed while the piezoelectric body is charged (and also while the piezoelectric is not charged). 
     Techniques are described for providing a haptic output and sensing a haptic input using a piezoelectric body. In some embodiments, the techniques limit a current flow into a haptic sensor circuit while charging a piezoelectric body to deliver a haptic output, and enable monitoring for a haptic input to the piezoelectric body while the piezoelectric body is charged. This and other embodiments are discussed in more detail below, with reference to  FIGS. 1-18 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanation only and should not be construed as limiting. 
       FIG. 1  shows a front view of an electronic device  100  incorporating a sample haptic interface, such as one of the haptic interfaces described herein. The electronic device  100  is illustrated as a smartphone, although this is not required and other electronic devices can incorporate the haptic interfaces described herein. These include, but are not limited to, wearable devices, tablet computers, cellular devices, peripheral input devices, game controllers, vehicle control circuits, laptop computers, industrial control circuits, consumer appliances, industrial machinery, and so on. 
     In the illustrated embodiment, the electronic device  100  includes a housing  110  to retain, support, and/or enclose various components of the electronic device  100 , such as a display  120 . The housing  110  may be a unitary housing, a housing that includes a front piece secured to a back piece, or a housing that includes any number or arrangement of pieces. The display  120  can include a stack of multiple layers including, for example, and in no particular order: a light-emitting display layer (e.g., an organic light emitting diode (OLED) layer), a cover layer, a touch input layer, a haptic interface layer, a biometric layer, and so on. Other embodiments can implement the display  120  in a different manner, such as with liquid crystal display (LCD) technology, electronic ink technology, quantum dot technology, organic electro luminescence (OEL) technology, or other light-emitting display technologies. The light-emitting display layer may be viewable through one or more of the other layers. Other embodiments can also include different numbers of layers. In some embodiments, a protective outer layer of the display  120  may define an input surface  130 . 
     Regardless of the implementation-specific display technology or technologies selected for a particular embodiment, the various layers of the display  120  may be adhered together with an optically transparent adhesive and/or may be supported by a common frame such that the layers abut one another. 
     The common frame can be made from any suitable material such as, but not limited to: metal, plastic, ceramic, acrylic, and so on. The common frame may be a multi-purpose component serving an additional function such as, but not limited to: providing an environmental and/or hermetic seal to one or more components of the display  120  or the electronic device  100 ; providing structural support to the housing  110 ; providing pressure relief to one or more components of the display  120  or the electronic device  100 ; providing and defining gaps between one or more layers of the display  120  for thermal venting and/or to permit flexing of the layers in response to a force (input or output) applied to the input surface  130 ; and so on. 
     In some embodiments, the layers of the display  120  may be attached or deposited onto separate substrates that may be laminated or bonded to each other. The display  120  may also include or be positioned adjacent to other layers suitable for improving the structural or optical performance of the display  120 , including, but not limited to, a cover glass sheet, polarizer sheets, color masks, and the like. Additionally, the display  120  may include a touch sensor (not shown) for determining the location of one or more touches on the input surface  130  of the electronic device  100 . In some embodiments, the touch sensor may be a capacitive touch sensor configured to detect the location and/or area of one or more touches of a user&#39;s finger and/or a passive or active stylus on the input surface  130 . The electronic device  100  may also include a haptic structure (e.g., a piezoelectric body) for both  1 ) providing a haptic output to a user of the electronic device  100  and  2 ) receiving a haptic input from the user. 
     The electronic device  100  can also include a processor, memory, power supply and/or battery, network connections, sensors, input/output mechanisms (e.g., devices or ports), acoustic elements, haptic elements, digital and/or analog circuits for performing and/or coordinating tasks of the electronic device  100 , and so on. For simplicity of illustration, the electronic device  100  is depicted in  FIG. 1  without many of these elements, each of which may be included, partially and/or entirely, within the housing  110  and may be operationally or functionally associated with, or coupled to, the display  120 . 
     One or more haptic structures (e.g., piezoelectric bodies  140 ) of a haptic interface can be disposed below the input surface  130 . The haptic structures may be arranged in an array or other pattern and positioned behind or within the display  120 , although haptic structures may also or alternatively be positioned behind or within non-display portions of the electronic device  100 , such as in sidewalls, rear walls, non-display portions of a front of the electronic device  100 , on a back side of the electronic device  100 , and so on. As a result of this arrangement, each haptic structure can provide localized haptic output, or receive local haptic input, to/from a user touching the display  120 . The haptic structures may be of any suitable size or shape. 
       FIGS. 2A, 2B, 3A, 3B, 4A, and 4B  show various anchoring configurations for piezoelectric bodies that may be used in conjunction with a haptic interface such as the haptic interface described with reference to  FIG. 1 . The anchoring configurations shown are examples only, and are not intended to limit the types of anchoring configurations that may be used for a piezoelectric body in a haptic interface. 
       FIGS. 2A and 2B  show a first anchoring configuration  200  for a piezoelectric body  205 .  FIG. 2A  shows the piezoelectric body  205  in a non-energized state, and  FIG. 2B  shows the piezoelectric body  205  in an energized state. 
     In accordance with the first anchoring configuration  200 , the piezoelectric body  205  may be clamped around its perimeter  210 , and when actuated (energized) may form a dome ( FIG. 2B ). When not actuated (non-energized), and by way of example, the piezoelectric body  205  may take the form of a round disc (see,  FIG. 2A ; or a dome of lower height). The piezoelectric body  205  shown in  FIGS. 2A and 2B  may be referred to as a piezo dome. 
       FIGS. 3A and 3B  show a second anchoring configuration  300  for a piezoelectric body  305 .  FIG. 3A  shows the piezoelectric body  305  in a non-energized state, and  FIG. 3B  shows the piezoelectric body  305  in an energized state. 
     In accordance with the second anchoring configuration  300 , the piezoelectric body  305  may be clamped at two ends (e.g., two opposite ends  310 ,  315 ), and when actuated (energized) may bend up in the middle (as shown) or down (not shown). When not actuated (non-energized), and by way of example, the piezoelectric body  305  may take the form of a flat bar or sheet of material. The piezoelectric body  305  shown in  FIGS. 3A and 3B  may be referred to as a piezo bender, clamped on both ends. 
       FIGS. 4A and 4B  show a third anchoring configuration  400  for a piezoelectric body  405 .  FIG. 4A  shows the piezoelectric body  405  in a non-energized state, and  FIG. 4B  shows the piezoelectric body  405  in an energized state. 
     In accordance with the third anchoring configuration  400 , the piezoelectric body  405  may be clamped at one end  410 , and when actuated (energized) may bend up or down at another end  415  (e.g., an opposite end). When not actuated (non-energized), and by way of example, the piezoelectric body  405  may take the form of a flat bar or sheet of material. The piezoelectric body  405  shown in  FIGS. 4A and 4B  may be referred to as a piezo bender, clamped on one end. 
       FIGS. 5A, 5B, and 5C  show sample constructions of a piezoelectric body. The sample constructions may be employed in the haptic interface described with reference to  FIG. 1 , with any of the anchoring configurations described with reference to  FIG. 2A, 2B, 3A, 3B, 4A , or  4 B, or with other types of haptic interfaces or piezoelectric anchoring configurations. 
       FIG. 5A  shows a unimorph construction of a piezoelectric body  500 , in which a first layer  505  of piezoelectric material may be attached to a second layer  510  of non-piezoelectric material (e.g., a non-piezoelectric elastic material, such as a flex circuit).  FIG. 5B  shows a bimorph construction of a piezoelectric body  515 , in which a first layer  520  of piezoelectric material may be attached to a second layer  525  of piezoelectric material.  FIG. 5C  shows a trimorph construction of a piezoelectric body  530 , in which a first layer  535  of piezoelectric material is attached to one side of a layer  540  of non-piezoelectric material (e.g., a non-piezoelectric elastic material, such as a flex circuit), and a second layer  545  of piezoelectric material is attached to an opposite side of the layer  540  of non-piezoelectric material. 
       FIG. 6  shows a cross-section of a piezoelectric body  600  attached to first and second substrates  605 ,  610  (e.g., a bottom substrate  605  and a top substrate  610 ). As shown in  FIG. 6 , each of the first substrate  605  and the second substrate  610  may include multiple layers, such as a nickel (Ni) alloy layer  615 , a copper (Cu) layer  620 , and a platinum (Pl) layer  625 . The copper layers  620  may include electrical conductors for routing signals between the piezoelectric body  600  and a circuit (e.g., a processor). The platinum layers  625  may act as stiffeners or ground shields for each substrate  605 ,  610 . The nickel alloy layers  615  may provide conductive pads to which electrodes  630  attached to the piezoelectric body  600  may be bonded using a conductive adhesive  635  (e.g., an isotropic conductive film (ICF) or other conductive adhesive). 
     Referring to  FIG. 7 , there is shown a block diagram of a haptic interface  700  capable of providing a haptic output and sensing a haptic input. The haptic interface  700  may be an example of the haptic interface described with reference to  FIG. 1 . 
     The haptic interface  700  may include a piezoelectric body  705 , first and second electrodes  710 ,  715  that are coupled to the piezoelectric body  705  to form a capacitor (C P ), and a control circuit  720 . The piezoelectric body  705  may take any of the forms described with reference to  FIGS. 2-5 , or other forms. In some embodiments, the piezoelectric body  705  may be configured as shown in  FIG. 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 5C , or  6 . The control circuit  720  may include a haptic actuator circuit  725  and a haptic sensor circuit  730 . The haptic actuator circuit  725  may be coupled to the first electrode  710 , and may be configured to charge the piezoelectric body  705  to provide a haptic output. The haptic sensor circuit  730  may be coupled to the second electrode  715 , and may be configured to sense an electrical change at the second electrode  715 . The electrical change may be a change in voltage, current, or charge, for example, and may be related to a haptic input (e.g., a force input) received by the piezoelectric body  705 . 
     Optionally, the control circuit  720  may also include an overcurrent protection circuit  735 . The overcurrent protection circuit  735  may be switchably operated (e.g., in response to a control signal) or automatically enabled (e.g., in response to an electrical change in the haptic interface  700 ) to limit a current flow into the haptic sensor circuit  730  while the haptic actuator circuit  725  is charging the piezoelectric body  705 . The overcurrent protection circuit  735  may be needed to protect the haptic sensor circuit  730  because of one or more orders of magnitude difference between a haptic actuation signal provided by the haptic actuator circuit  725  to the piezoelectric body  705 , to actuate the piezoelectric body  705 , and a haptic input signal intended to be sensed by the haptic sensor circuit  730  (e.g., the haptic actuation signal may be one or more orders of magnitude greater than the haptic input signal). 
     A digital sampling circuit  740 , such as an analog-to-digital converter (ADC), may be coupled to an output of the haptic sensor circuit  730 . 
       FIG. 8  shows a sample first circuit schematic  800  for a haptic interface, such as the haptic interface of  FIG. 7 . The haptic interface may include a piezoelectric body  805 , a first electrode  810  coupled to the piezoelectric body  805 , and a second electrode  815  coupled to the piezoelectric body  805 . By way of example, the piezoelectric body  805  is depicted as a capacitor C P  having a variable capacitance. In some cases, the piezoelectric body  805  may represent multiple piezoelectric bodies. The haptic interface may also include a control circuit  820 . The control circuit  820  may include a haptic actuator circuit  825 , a haptic sensor circuit  830 , and an overcurrent protection circuit  835 . 
     The haptic actuator circuit  825  may be coupled to the first electrode  810  and may be configured to charge the piezoelectric body  805 . The charging may cause the piezoelectric body  805  to provide a haptic output (e.g., compress, deflect, deform, or otherwise physically change shape). The haptic sensor circuit  830  may be coupled to the second electrode  815  and may be configured to sense an electrical change (e.g., a change in voltage, change in current, or change in charge) at the second electrode  815 . The electrical change may be related to a haptic input received by the piezoelectric body  805 . The overcurrent protection circuit  835  may be coupled to the second electrode  815  and may be configured to limit a current flow into the haptic sensor circuit  830  while the haptic actuator circuit  825  is charging the piezoelectric body  805 . 
     The haptic actuator circuit  825  may include a power source  840  and a first transistor  845 , coupled in series between the first electrode  810  and a discharge node  850  (e.g., a ground). By way of example, the power source  840  is shown to be a 48V power source. In other embodiments, the power source  840  could supply a higher or lower voltage. The first transistor  845  may be coupled between the power source  840  and the first electrode  810  via its source and drain terminals, and may have a control input  855  (e.g., a gate input) configured to receive a signal that causes the first transistor  845  to open or close a current path between the first electrode  810  and the power source  840 . The haptic actuator circuit  825  may also include a second transistor  860  coupled between the first electrode  810  and the discharge node  850 . The second transistor  860  may be coupled between the first electrode  815  and the discharge node  850  via its source and drain terminals, and may have a control input  865  (e.g., a gate input) configured to receive a signal that causes the second transistor  860  to open or close a current path between the first electrode  810  and the discharge node  850 . 
     The haptic sensor circuit  830  may include a sense amp  870  having a negative input coupled to the second electrode  815 , a positive input coupled to the discharge node  850 , and an output  875 . A resistor  880  may be coupled between the negative input and the output  875 . The configuration of the sense amp  870  is that of a transimpedance amplifier, which has no memory and can sense haptic input faster than certain other amplifier configurations. In some embodiments, the resistor  880  may be part of (or replaced by) a set of impedances  885 . In some embodiments, the set of impedances  885  may include a number of resistors and capacitors connected in parallel. In some embodiments, one or more (or each) of the parallel-connected impedances may be connected in series with a switch. In these latter embodiments, the switches may be operated by the control circuit  820  to connect or disconnect impedances between the negative input and output  875  of the sense amp  870 , thereby enabling the sense amp  870  to be operated in different modes (e.g., as a transimpedance amplifier or integrator). 
     The overcurrent protection circuit  835  may include a third transistor  890  coupled between the second electrode  810  and the discharge node  850 , and also between the positive input and the negative input of the sense amp  870 . The third transistor  890  may be coupled between the second electrode  815  and the discharge node  850  via its source and drain terminals, and may have a control input  895  (e.g., a gate input) configured to receive a signal that causes the third transistor  890  to open or close a current path between the second electrode  815  and the discharge node  850 . 
     By way of example, the first, second, and third transistors  845 ,  860 ,  890  are shown to be N channel enhancement type metal oxide semiconductor field effect transistors (MOSFETs). In other examples, the transistors  845 ,  860 ,  890  may take other forms. 
     To charge the piezoelectric body  805  and provide a haptic output, the first transistor  845  may be closed and the second transistor  860  may be opened. While charging the piezoelectric body  805 , the third transistor  890  may be closed to provide overcurrent protection for the haptic sensor circuit  830 . In some cases, the third transistor  890  may be closed at the same time (and in some cases in response to the same control signal) as the first transistor  845 . In other cases, the third transistor  890  may be closed prior to closing the first transistor  845 . In still other cases, the third transistor  890  may be closed a predetermined time after closing the first transistor  845 , or upon sensing a predetermined current flow into the haptic sensor circuit  830 . If the piezoelectric body  805  is charged or discharged at a slow enough rate, the haptic sensor circuit  830  may monitor for haptic input to the piezoelectric body  805  during part or all of the charge time or discharge time. However, when the piezoelectric body  805  is charged or discharged quickly (which is considered typical), the haptic sensor circuit  830  may not monitor for haptic input to the piezoelectric body  805  during part or all of the charge time or discharge time (e.g., charging and sensing operations, or time periods, may be multiplexed). 
     To discharge the piezoelectric body  805 , the second transistor  860  may be closed. 
     The haptic sensor circuit  830  may monitor for a haptic input to the piezoelectric body  805  by monitoring for an electrical change (e.g., a change in voltage, current, or charge) at the second electrode  815 . To monitor for a haptic input, the third transistor  890  may be opened, while either (but not both) of the first and second transistors  845 ,  860  is closed. The haptic sensor circuit  830  may monitor for a haptic input during times when there is no charge on the piezoelectric body  805  (e.g., after the second transistor  860  has been closed and any charge on the piezoelectric body  805  has been discharged), or when there is a full charge on the piezoelectric body  805  (e.g., after the first transistor  845  has been closed and the piezoelectric body  805  has been fully charged). 
       FIG. 9  shows a graph  900  of voltage at the second electrode  815 , over time, for various charging scenarios  905 ,  910 ,  915  of the piezoelectric body  805  shown in  FIG. 8 . Under each scenario  905 ,  910 ,  915 , the voltage ramps up to a steady state high voltage (e.g., 48V). The slope of each charging ramp may determine an intensity of a haptic output. In the first and second scenarios  905 ,  910 , a haptic input may be sensed at a steady state low voltage (e.g., 0V) and at the steady state high voltage, but not during charging of the piezoelectric body, because the rate of charging requires activation of the overcurrent protection circuit  835 . In the third scenario  915 , the charging ramp may be slow enough that the overcurrent protection circuit  835  does not need to be activated, and a haptic input may be sensed at the steady state low voltage, during charging, and at the steady state high voltage. In scenarios in which the overcurrent protection circuit  835  needs to be employed, the speed of recovering from overcurrent protection may determine the amount of haptic input information loss (e.g., during periods of overcurrent protection) and rate of haptic input information gathering. 
       FIG. 10  shows a sample second circuit schematic  1000  for a haptic interface, such as the haptic interface of  FIG. 7 . The haptic interface may include a piezoelectric body  1005 , a first electrode  1010  coupled to the piezoelectric body  1005 , and a second electrode  1015  coupled to the piezoelectric body  1005 . By way of example, the piezoelectric body  1005  is depicted as a capacitor C P  having a variable capacitance. In some cases, the piezoelectric body  1005  may represent multiple piezoelectric bodies. The haptic interface may also include a control circuit  1020 . The control circuit  1020  may include a haptic actuator circuit  1025 , a haptic sensor circuit  1030 , and an overcurrent protection circuit  1035 . 
     The haptic actuator circuit  1025  may be coupled to the first electrode  1010  and may be configured to charge the piezoelectric body  1005 . The charging may cause the piezoelectric body  1005  to provide a haptic output (e.g., compress, deflect, deform, or otherwise physically change shape). The haptic sensor circuit  1030  may be coupled to the second electrode  1015  and may be configured to sense an electrical change (e.g., a change in voltage, change in current, or change in charge) at the second electrode  1015 . The electrical change may be related to a haptic input received by the piezoelectric body  1005 . The overcurrent protection circuit  1035  may be coupled to the second electrode  1015  and may be configured to limit a current flow into the haptic sensor circuit  1030  while the haptic actuator circuit  1025  is charging the piezoelectric body  1005 . 
     The haptic actuator circuit  1025  may include a power source  1040  and a first transistor  1045 , coupled in series between the first electrode  1010  and a discharge node  1050  (e.g., a ground). By way of example, the power source  1040  is shown to be a 48V power source. In other embodiments, the power source  1040  could supply a higher or lower voltage. The first transistor  1045  may be coupled between the power source  1040  and the first electrode  1010  via its source and drain terminals, and may have a control input  1055  (e.g., a gate input) configured to receive a signal that causes the first transistor  1045  to open or close a current path between the first electrode  1010  and the power source  1040 . The haptic actuator circuit  1025  may also include a second transistor  1060  coupled between the first electrode  1010  and the discharge node  1050 . The second transistor  1060  may be coupled between the first electrode  1010  and the discharge node  1050  via its source and drain terminals, and may have a control input  1065  (e.g., a gate input) configured to receive a signal that causes the second transistor  1060  to open or close a current path between the first electrode  1010  and the discharge node  1050 . 
     The haptic sensor circuit  1030  may include a sense amp  1070  having a negative input coupled to the second electrode  1010 , a positive input coupled to the discharge node  1050 , and an output  1075 . A resistor  1080  may be coupled between the negative input and the output  1075 . The configuration of the sense amp  1070  is that of a transimpedance amplifier, which has no memory and can sense haptic input faster than certain other amplifier configurations. In some embodiments, the resistor  1080  may be part of (or replaced by) a set of impedances  1085 . In some embodiments, the set of impedances  1085  may include a number of resistors and capacitors connected in parallel. In some embodiments, one or more (or each) of the parallel-connected impedances may be connected in series with a switch. In these latter embodiments, the switches may be operated by the control circuit  1020  to connect or disconnect impedances between the negative input and output  1075  of the sense amp  1070 , thereby enabling the sense amp  1070  to be operated in different modes (e.g., as a transimpedance amplifier or integrator). 
     The overcurrent protection circuit  1035  may include a clamper circuit  1090  coupled between the second electrode  1015  and the discharge node  1050 , and also between the positive input and the negative input of the sense amp  1070 . The clamper circuit  1090  may include a forward-biased diode  1095  coupled in parallel with a reverse-biased diode  1098 . Parameters of the diodes  1095 ,  1098  may be configured such that the clamper circuit  1090  automatically limits the current flow into the haptic sensor circuit  1030 . 
     By way of example, the first and second transistors  1045 ,  1060  are shown to be N channel enhancement type MOSFETs. In other examples, the transistors  1045 ,  1060  may take other forms. 
     To charge the piezoelectric body  1005  and provide a haptic output, the first transistor  1045  may be closed and the second transistor  1060  may be opened. While charging the piezoelectric body  1005 , the clamper circuit  1090  may automatically conduct to divert at least a portion of the current flow through the second electrode  1015  from into the haptic sensor circuit  1030  to the discharge node  1050 , to provide overcurrent protection for the haptic sensor circuit  1030 . For example, the clamper circuit  1090  may automatically conduct when the current flow (I CP ) through the second electrode  1015  exceeds the maximum current (I opamp ) supported by the sense amp  1070 . 
     To discharge the piezoelectric body  1005 , the second transistor  1060  may be closed. 
     When the clamper circuit  1090  is in an inactive state (e.g., when the piezoelectric body  1005  is charged to a steady-state high voltage or is at a steady-state low voltage), the haptic sensor circuit  1030  may monitor for a haptic input to the piezoelectric body  1005  by monitoring for an electrical change (e.g., a change in voltage, current, or charge) at the second electrode  1015 . If the piezoelectric body  1005  is charged or discharged at a slow enough rate, the haptic sensor circuit  1030  may monitor for haptic input to the piezoelectric body  1005  during part or all of the charge time or discharge time. However, when the piezoelectric body  1005  is charged or discharged quickly (which is considered typical), the haptic sensor circuit  1030  may not monitor for haptic input to the piezoelectric body  1005  during part or all of the charge time or discharge time (e.g., charging and sensing operations, or time periods, may be multiplexed). 
       FIG. 11  shows a sample third circuit schematic  1100  for a haptic interface, such as the haptic interface of  FIG. 7 . The haptic interface may include a piezoelectric body  1105 , a first electrode  1110  coupled to the piezoelectric body  1105 , and a second electrode  1115  coupled to the piezoelectric body  1105 . By way of example, the piezoelectric body  1105  is depicted as a capacitor C P  having a variable capacitance. In some cases, the piezoelectric body  1105  may represent multiple piezoelectric bodies. The haptic interface may also include a control circuit  1120 . The control circuit  1120  may include a haptic actuator circuit  1125 , a haptic sensor circuit  1130 , and an overcurrent protection circuit  1135 . 
     The haptic actuator circuit  1125  may be coupled to the first electrode  1110  and may be configured to charge the piezoelectric body  1105 . The charging may cause the piezoelectric body  1105  to provide a haptic output (e.g., compress, deflect, deform, or otherwise physically change shape). The haptic sensor circuit  1130  may be coupled to the second electrode  1115  and may be configured to sense an electrical change (e.g., a change in voltage, change in current, or change in charge) at the second electrode  1115 . The electrical change may be related to a haptic input received by the piezoelectric body  1105 . The overcurrent protection circuit  1135  may be coupled to the second electrode  1115 , and may be configured to limit a current flow into the haptic sensor circuit  1130  while the haptic actuator circuit  1125  is charging the piezoelectric body  1105 . 
     The haptic actuator circuit  1125  may include a power source  1140  coupled between the first electrode  1110  and a discharge node  1145  (e.g., a ground). By way of example, the power source  1140  is shown to be a 48V power source. In other embodiments, the power source  1140  could supply a higher or lower voltage. In contrast to the haptic interfaces described with reference to  FIGS. 8 and 10 , the haptic actuator circuit  1125  may maintain the piezoelectric body  1105  in a continually charged state. 
     The haptic sensor circuit  1130  may include a sense amp  1150  having a negative input coupled to the second electrode  1115 , a positive input coupled to the discharge node  1145 , and an output  1155 . A resistor  1160  may be coupled between the negative input and the output  1155 . 
     The overcurrent protection circuit  1135  may include a charge integration capacitor  1165  coupled between the second electrode  1115  and the output  1155  of the sense amp  1150 . The charge integration capacitor  1165  may integrate charge leaked from the piezoelectric body  1105  over time. The charge integration capacitor  1165  may also be used to distinguish a force input to the piezoelectric body  1105  of short duration versus a force input of long duration. The charge on the charge integration capacitor  1165  may be periodically cleared (e.g., reset before performing a new sensing operation) by an integrated charge discharge circuit coupled to the charge integration capacitor  1165 . The integrated charge discharge circuit may have a control input configured to receive a control signal that causes the integrated charge discharge circuit to discharge a charge integrated by the charge integration capacitor  1165 . 
       FIG. 12  shows a sample fourth circuit schematic  1200  for a haptic interface, such as the haptic interface of  FIG. 7 . The haptic interface may include a piezoelectric body  1205 , a first electrode  1210  coupled to the piezoelectric body  1205 , and a second electrode  1215  coupled to the piezoelectric body  1205 . By way of example, the piezoelectric body  1205  is depicted as a capacitor C P  having a variable capacitance. In some cases, the piezoelectric body  1205  may represent multiple piezoelectric bodies. The haptic interface may also include a control circuit  1220 . The control circuit  1220  may include a haptic actuator circuit  1225 , a haptic sensor circuit  1230 , and an overcurrent protection circuit  1235 . 
     The haptic actuator circuit  1225  may be coupled to the first electrode  1210  and may be configured to charge the piezoelectric body  1205 . The charging may cause the piezoelectric body  1205  to provide a haptic output (e.g., compress, deflect, deform, or otherwise physically change shape). The haptic sensor circuit  1230  may be coupled to the second electrode  1215  and may be configured to sense an electrical change (e.g., a change in voltage, change in current, or change in charge) at the second electrode  1215 . The electrical change may be related to a haptic input received by the piezoelectric body  1205 . The overcurrent protection circuit  1235  may be coupled to the second electrode  1215  and configured to limit a current flow into the haptic sensor circuit  1230  while the haptic actuator circuit  1225  is charging the piezoelectric body  1205 . 
     The haptic actuator circuit  1225  may include a power source  1240  and a first transistor  1245 , coupled in series between the first electrode  1210  and a discharge node  1250  (e.g., a ground). By way of example, the power source  1240  is shown to be a 48V power source. In other embodiments, the power source  1240  could supply a higher or lower voltage. The first transistor  1245  may be coupled between the power source  1240  and the first electrode  1210  via its source and drain terminals, and may have a control input  1255  (e.g., a gate input) configured to receive a signal that causes the first transistor  1245  to open or close a current path between the first electrode  1210  and the power source  1240 . The haptic actuator circuit  1225  may also include a second transistor  1260  coupled between the first electrode  1210  and the discharge node  1250 . The second transistor  1260  may be coupled between the first electrode  1210  and the discharge node  1250  via its source and drain terminals, and may have a control input  1265  (e.g., a gate input) configured to receive a signal that causes the second transistor  1260  to open or close a current path between the first electrode  1210  and the discharge node  1250 . 
     The haptic sensor circuit  1230  may include a sense amp  1270  having a positive input coupled to the second electrode  1215 , a negative input coupled to the discharge node  1250 , and an output  1275 . 
     The overcurrent protection circuit  1235  may include a third transistor  1280  coupled between the second electrode  1215  and the discharge node  1250 , and also between the positive input and the negative input of the sense amp  1270 . The third transistor  1280  may be coupled between the second electrode  1215  and the discharge node  1250  via its source and drain terminals, and may have a control input  1285  (e.g., a gate input) configured to receive a signal that causes the third transistor  1280  to open or close a current path between the second electrode  1215  and the discharge node  1250 . 
     The first, second, and third transistors may take various forms. 
     To charge the piezoelectric body  1205  and provide a haptic output, the first transistor  1245  may be closed and the second transistor  1260  may be opened. While charging the piezoelectric body  1205 , the third transistor  1280  may be closed to provide overcurrent protection for the haptic sensor circuit  1230 . In some cases, the third transistor  1280  may be closed at the same time (and in some cases in response to the same control signal) as the first transistor  1245 . In other cases, the third transistor  1280  may be closed prior to closing the first transistor  1245 . In still other cases, the third transistor  1280  may be closed a predetermined time after closing the first transistor  1245 , or upon sensing a predetermined current flow into the haptic sensor circuit  1230 . 
     To discharge the piezoelectric body  1205 , the second transistor  1260  may be closed. 
     The haptic sensor circuit  1230  may monitor for a haptic input to the piezoelectric body  1205  by monitoring for an electrical change (e.g., a change in voltage, current, or charge) at the second electrode  1215 . To monitor for a haptic input, the third transistor  1280  may be opened, while either (but not both) of the first and second transistors  1245 ,  1260  is closed. The haptic sensor circuit  1230  may monitor for a haptic input during times when there is no charge on the piezoelectric body  1205  (e.g., after the second transistor  1260  has been closed and any charge on the piezoelectric body  1205  has been discharged), but not at times when there is a full charge on the piezoelectric body  1205  (e.g., after the first transistor  1245  has been closed and the piezoelectric body  1205  has been fully charged). 
       FIG. 13  shows a sample graph  1300  of voltage at the second electrode  1215 , over time, for the piezoelectric body  1205  shown in  FIG. 12 . When charging the piezoelectric body  1205  to provide a haptic output (by asserting the ϕ 1i  control signal), the voltage ramps up to a steady state high voltage (e.g., 48V). After charging the piezoelectric body  1205 , the piezoelectric body  1205  needs to be discharged (by asserting the ϕ 2  control signal) before monitoring for a haptic input (e.g., at 0V). 
       FIG. 14  shows a surface  1400  of an electronic device that may incorporate a haptic interface  1405  such as one of the haptic interfaces described with reference to  FIG. 1, 7, 8, 10, 11 , or  12 . In some examples, the electronic device  1400  may be a smartphone, a tablet computer, or a wearable device (e.g., a watch). 
     In some embodiments, the surface  1400  may be part of a light-emitting display or a surface surrounding a light-emitting display. In some embodiments, the haptic interface  1405  may be part of a movable or generally immovable button  1410 , which button  1410  has a fixed or movable (e.g., virtual) location on the surface  1400 . In some embodiments, the haptic interface  1405  may be part of a keyboard (e.g., part of a key) on the surface  1400 , which keyboard may be have movable or generally immovable keys. In some embodiments, the haptic interface  1405  may include a movable pin in place of the button  1410 , or the button  1410  may include a movable pin (not shown). The haptic interface  1405  may include a piezoelectric body  1415 , and a control circuit  1420  such as one of the control circuits described with reference to  FIG. 8, 10, 11 , or  12 . The control circuit  1420  may configure the haptic interface  1405  as a haptic sensor (e.g., to sense a force input provided by a user of the electronic device), a haptic actuator (e.g., to provide a tactile output), or both simultaneously, as described in this disclosure. In some cases, the piezoelectric body  1415  may sense a force input while the piezoelectric body  1415  is charged or actuated and/or when the piezoelectric body  1415  is not charged or actuated. 
       FIG. 15  shows an electronic device  1500  that may incorporate a haptic interface such as one of the haptic interfaces described with reference to  FIG. 1, 7, 8, 10, 11 , or  12 . By way of example, the electronic device  1500  is shown to be a watch, though the electronic device  1500  could take other wearable forms or be a different type of electronic device (e.g., a non-wearable electronic device). 
     The electronic device  1500  may include a haptic interface  1505  that is usable by the electronic device  1500  as a notifier (e.g., an alarm or reminder) or presence sensor (e.g., a haptic prompt to inquiry whether a user is still engaged in an activity (e.g., exercising or performing a task) or still engaged with an application or utility running on the electronic device  1500  (e.g., a stopwatch utility)). In some examples, the haptic interface  1505  may include a piezoelectric body that is capable of providing a haptic output (e.g., a raised bump or pin). As shown, the haptic interface  1505  may be provided on an exterior surface of a smart watch band  1510 . Alternatively, the haptic interface  1505  may be provided on an interior surface of the smart watch band  1510 , or at another location on the electronic device  1500 . In some examples, the piezoelectric body may be associated with one of the control circuits described with reference to  FIG. 7, 8, 10, 11 , or  12 . 
     The haptic interface  1505  may sense a force input when it is actuated (e.g., when a piezoelectric body of the haptic interface  1505  is charged). In the case of an alarm or reminder, a user&#39;s force input to the haptic interface  1505  may cause the electronic device to clear the alarm or reminder (e.g., discharge a piezoelectric body or otherwise discontinue the haptic output). 
     Referring now to  FIG. 16 , there is shown a method  1600  of operating a haptic interface. In some examples, the method  1600  may be performed by an electronic device, such as the electronic device described with reference to  FIG. 1, 14 , or  15 . 
     At  1605 , the method  1600  may include charging a piezoelectric body of the haptic interface to deliver a haptic output. The operation(s) at  1605  may be performed, for example, by the haptic actuator circuit described with reference to  FIG. 8, 10, 11 , or  12 . 
     At  1610 , the method  1600  may include limiting a current flow into a haptic sensor circuit while charging the piezoelectric body. The operation(s) at  1610  may be performed, for example, by the overprotection circuit described with reference to  FIG. 8, 10, 11 , or  12 . 
     At  1615 , the method  1600  may include monitoring for a haptic input to the piezoelectric body using the haptic sensor circuit while the piezoelectric body is charged. The operation(s) at  1615  may be performed, for example, by the haptic sensor circuit described with reference to  FIG. 8, 10, 11 , or  12 . 
     In some examples, the method  1600  may include monitoring for a haptic input prior to charging the piezoelectric body and/or while charging the piezoelectric body. 
     In some examples, limiting the current flow into the haptic sensor circuit may include diverting at least a portion of the current flow from into the haptic sensor circuit to a discharge node. In some examples, diverting at least a portion of the current flow from into the haptic sensor circuit to the discharge node may include applying a control signal to a transistor. The transistor may be coupled between a first input and a second input of the haptic sensor circuit. Also, the first input may be coupled to an electrode attached to the piezoelectric body, and the second input may be coupled to the discharge node. In other examples, diverting at least a portion of the current flow from into the haptic sensor circuit to the discharge node may include automatically diverting at least the portion of the current flow based on a parameter of a diode. 
     In some examples, limiting the current flow into the haptic sensor circuit may include integrating a charge using a charge integrator (e.g., a capacitor) coupled between an input of the haptic sensor circuit and an output of the haptic sensor circuit, and clearing the integrated charge before monitoring for the haptic input. 
       FIG. 17  shows another method  1700  of operating a haptic interface. In some examples, the method  1700  may be performed by an electronic device, such as the electronic device described with reference to  FIG. 1, 14 , or  15 . 
     At  1705 , the method  1700  may include charging a piezoelectric body of the haptic interface to deliver a haptic output. The operation(s) at  1705  may be performed, for example, by the haptic actuator circuit described with reference to  FIG. 8, 10, 11 , or  12 . 
     At  1710 , the method  1700  may include monitoring for a haptic input to the piezoelectric body while the piezoelectric body is charged. The operation(s) at  1710  may be performed, for example, by the haptic sensor circuit described with reference to  FIG. 8, 10, 11 , or  12 . 
       FIG. 18  shows a sample electrical block diagram of an electronic device  1800 , which may be an example block diagram of the electronic device described with reference to  FIG. 1, 14 , or  15 . The electronic device  1800  can include a display  1805  (e.g., a light-emitting display), a processor  1810 , a power source  1815 , a memory  1820  or storage device, a sensor  1825 , an input/output (I/O) mechanism  1830  (e.g., an input/output device and/or input/output port), and a haptic interface  1835 . The processor  1810  can control some or all of the operations of the electronic device  1800 . The processor  1810  can communicate, either directly or indirectly, with substantially all of the components of the electronic device  100 . For example, a system bus or other communication mechanism  1840  can provide communication between the processor  1810 , the power source  1815 , the memory  1820 , the sensor  1825 , the input/output mechanism  1830 , and/or the haptic interface  1835 . 
     The processor  1810  can be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor  1810  can be a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices. As described herein, the term “processor” is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or other suitably configured computing element or elements. 
     It should be noted that the components of the electronic device  1800  can be controlled by multiple processors. For example, select components of the electronic device  1800  may be controlled by a first processor and other components of the electronic device  1800  may be controlled by a second processor, where the first and second processors may or may not be in communication with each other. 
     The power source  1815  can be implemented with any device capable of providing energy to the electronic device  1800 . For example, the power source  1815  may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power source  1815  can be a power connector or power cord that connects the electronic device  1800  to another power source, such as a wall outlet. 
     The memory  1820  can store electronic data that can be used by the electronic device  1800 . For example, the memory  1820  can store electrical data or content such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, and data structures or databases. The memory  1820  can be configured as any type of memory. By way of example only, the memory  1820  can be implemented as random access memory, read-only memory, Flash memory, removable memory, other types of storage elements, or combinations of such devices. 
     The electronic device  1800  may also include one or more sensors  1825  positioned substantially anywhere on the electronic device  1800 . The sensor(s)  1825  can be configured to sense substantially any type of characteristic, such as but not limited to, pressure, light, touch, heat, movement, relative motion, biometric data, and so on. For example, the sensor(s)  1825  may include a heat sensor, a position sensor, a light or optical sensor, an accelerometer, a pressure transducer, a gyroscope, a magnetometer, a health monitoring sensor, and so on. Additionally, the one or more sensors  1825  can utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasound, piezoelectric, and thermal sensing technology. 
     The  110  mechanism  1830  can transmit and/or receive data from a user or another electronic device. An  110  device can include a display, a touch sensing input surface such as a track pad, one or more buttons (e.g., a graphical user interface “home” button), one or more cameras, one or more microphones or speakers, one or more ports such as a microphone port, and/or a keyboard. Additionally or alternatively, an  110  device or port can transmit electronic signals via a communications network, such as a wireless and/or wired network connection. Examples of wireless and wired network connections include, but are not limited to, cellular, Wi-Fi, Bluetooth, IR, and Ethernet connections. 
     The haptic interface  1835  may be operably connected to the processor  1810 , display  1805 , or other components of the electronic device  1800 . The haptic interface  1835  may provide the processor  1810  a signal corresponding to compression, deflection, deformation, or other movement of one or more piezoelectric bodies of the haptic interface  1835 , and the processor  1810  may wake up a portion of the electronic device  1800 , manipulate a graphical element on the display  1805  of the electronic device  1800 , or perform another operation in response to the signal. The processor  1810  may also activate the haptic interface  1835  to solicit a user&#39;s attention, enhance the user&#39;s interaction experience with the electronic device  1800 , displace the electronic device  1800  or a component of the electronic device  1800 , or provide any other suitable notification or user experience. The haptic interface  1835  may be activated, for example, by generating a signal that causes one or more piezoelectric bodies of the haptic interface  1835  to compress, deflect, deform, or otherwise physically change. The haptic interface  1835  may also function as a sensor  1825 , and may receive force input from a user of the electronic device  1800 . 
     The foregoing description, for purposes of explanation, uses specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20170718
Publication Date: 20200414
Grant Date: 20200414
Priority Date: 20170718
Inventors: ZHANG, ZHIPENG
KOCH, RICHARD H.
SONGATIKAMAS, TEERA
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04886", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L41/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L41/09", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L41/083", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L41/0472", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04886", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L41/0825", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04886", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10N30/802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/872", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10N30/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/802", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10N30/101", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65023211