Patent Publication Number: US-2023142264-A1

Title: Haptic Structure for Providing Haptic Outputs at an Electronic Device

Description:
This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 63/227,484, filed Nov. 9, 2021 and titled “Haptic Structure for Providing Haptic Outputs at an Electronic Device,” the disclosure of which is hereby incorporated herein by reference in its entirety 
    
    
     FIELD 
     The described embodiments relate generally to providing haptic outputs at an electronic device. More particularly, the present embodiments relate to piezoelectric structures for providing haptic outputs at an electronic device. 
     BACKGROUND 
     Electronic devices such as laptops, tablets, and smartphones often have different ways of notifying users of different events that occur. This can include playing sounds, providing haptic outputs such as a vibration, displaying a visual notification, and so on. The haptic output may be provided by an actuator that utilizes a vibratory motor or an oscillating motor. However, these vibratory motors typically vibrate the entire electronic device and are not able to provide a localized haptic output. Further, typical vibratory motors tend to be bulky, and it may be desirable to have haptic structures that can be positioned in smaller spaces and/or take up less room. 
     SUMMARY 
     Embodiments are directed to an electronic device that includes a cover and a haptic module positioned below the cover. The haptic module may include a substrate positioned below the cover, a spacer positioned between the substrate and the cover and coupling the substrate to the cover, and a piezoelectric element positioned on the substrate and offset from the cover to define a gap between the piezoelectric element and the cover. The electronic device can also include a sensor coupled to the cover and configured to detect an input, and a processing unit operably coupled to the piezoelectric element and configured to cause the piezoelectric element to deflect the cover in response to the sensor detecting the input. 
     Embodiments are also directed to an electronic device that includes an enclosure component, a cover coupled to the enclosure component, and first and second haptic modules positioned below the cover. Each of the first and second haptic modules may include an actuation strip that includes a substrate and a piezoelectric element attached to the substrate. Each of the first and second haptic modules may also include a spacer positioned between the actuation strip and the cover and defining a gap between the actuation strip and the cover. The electronic device can also include a touch sensor positioned along the cover and configured to determine a location of a touch input to the cover, and a processing unit configured to cause at least one of the first haptic module or the second haptic module to actuate in response to the touch input. 
     Embodiments are further directed to an electronic device that includes an upper portion comprising a display, and a lower portion coupled to the upper portion where the lower portion defines a keyboard and a track pad. The electronic device can include a haptic module positioned below the track pad. The haptic module can include a spacer attached to an internal surface of the track pad and an actuation strip coupled to the spacer thereby defining a gap between the actuation strip and the internal surface of the track pad. The actuation strip may include a substrate and a piezoelectric element coupled to the substrate. The electronic device can further include a processing unit operably coupled to the haptic module and configured to cause a deflection of the actuation strip to produce a haptic output along an outer surface of the track pad. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG.  1    shows an example of an electronic device that includes haptic structures for providing localized haptic outputs; 
         FIG.  2    shows a cross-sectional view of the haptic structure shown in  FIG.  1   ; 
         FIGS.  3 A- 3 C  show a cross-sectional view of example neutral and actuated states of the haptic structure shown in  FIG.  1   ; 
         FIGS.  4 A- 4 C  show another cross-sectional view of example neutral and actuated states of the haptic structure shown in  FIG.  1   ; 
         FIGS.  5 A- 5 B  show perspective views of example haptic structures; 
         FIGS.  6 A- 6 B  show perspective views of example haptic structures; 
         FIG.  7    shows a top view of a portion of an electronic device that includes haptic structures and force sensors; 
         FIGS.  8 A- 8 B  show cross-sectional views of example haptic structures from  FIG.  7   ; 
         FIG.  9 A  shows a top view of a portion of an electronic device that includes haptic structures and force sensors; 
         FIG.  9 B  shows a cross-sectional view of the example haptic structure shown in  FIG.  9 A ; and 
         FIG.  10    is an example block diagram of an electronic device including haptic structures for providing localized outputs. 
     
    
    
     It should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Embodiments disclosed herein are directed to electronic devices that include haptic modules for providing localized haptic outputs. The haptic modules can be coupled to an input mechanism of an electronic device, which can include touch-sensitive surface(s) such as a track pad, a touch-sensitive display and/or a virtual keyboard, or other housing structures. The haptic modules can be coupled directly to an input mechanism and cause deformation of the input mechanism through actuation of a piezoelectric element. In some cases, multiple haptic modules can be positioned along an input mechanism to produce a unified output that results from the combination of the deformation caused by each haptic module. The haptic modules described herein can include a structure that includes a thin stack-up while reducing stress on a piezoelectric element. In some cases, the structure of the haptic modules described herein may also reduce manufacturing complexity by allowing for a range of mounting orientations and/or reducing alignment sensitivity. The haptic modules may also include touch sensors that can determine a location and/or force of a touch to the input mechanism. In this regard, one or more of the haptic structures can be actuated to provide a coordinated and localized haptic output at the input mechanism. 
     The haptic modules can include a structure that reduces stress on the piezoelectric element by offsetting the piezoelectric element from the input mechanism. The haptic module can include a substrate that is coupled to the input mechanism by a spacer. The spacer can offset the substrate from the input mechanism by creating a gap between the substrate and the input mechanism. The piezoelectric element can be coupled to the substrate and offset from the input mechanism. The spacer can also create a gap between the piezoelectric element and the input mechanism. When the piezoelectric element is actuated, the motion of the piezoelectric element can be transferred through the substrate and spacer to cause the input mechanism to deform. Additionally or alternatively, when the input mechanism is deformed, for example, in response to a touch input, the deformation of the input surface is transferred to the piezoelectric element through the spacer and the substrate. In this regard, the spacer and the substrate may function to reduce the stress on the piezoelectric element as compared to a piezoelectric element that is coupled directly to the input mechanism. 
     In some cases, an electronic device can include a case and the input mechanism can be coupled to the case. The haptic module can be suspended from an inner surface of the input mechanism. The case can include an opening that is aligned with the haptic module. In this regard the haptic module can be positioned within the opening and/or deform into the opening when the piezoelectric element is actuated. The structure of the haptic module may be referred to as being “self-contained,” which is used here to indicate that the haptic module can deform a structure, such as an input mechanism, without being attached to a secondary support structure such as another portion of the housing. For example, the haptic module can cause deformation in the input mechanism by expanding and contracting along one or more first directions, which causes deformation of the input surface in one or more second directions that may be substantially orthogonal to the one or more first directions. The actuation of the haptic module can cause buckling type movements in the input mechanism. In this regard, the self-contained structure of the haptic module may be less sensitive to alignment on the input mechanism and/or reduce the overall thickness of the haptic module as compared to other types of haptic actuators. 
     In some cases, the electronic device described herein can include a touch sensor. The touch sensor can include an array of first electrodes that are positioned on an input mechanism and that move with the input mechanism. The touch sensor can include an array of second electrodes that remain substantially fixed with respect to movement of the array of first electrodes. In this regard, the touch sensor can output signals that are indicative of changes in distance between the first and second arrays of electrodes and the electronic device can determine a location of touch input and/or an estimated force of the touch input based on the touch sensor signals. The electronic device can actuate one or more haptic modules to produce a haptic output at the input mechanism in response to touch input. In some cases, the haptic output can be generated by an actuation of a single haptic module. In other cases, the haptic output can be a combination of outputs from multiple haptic modules positioned along the input mechanism. For example, each haptic module can be independently actuated to produce a unified output that results from the combination of the independently actuated haptic modules. 
     These and other embodiments are discussed below with reference to  FIGS.  1 - 10   . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
       FIG.  1    shows an example electronic device  100  that includes haptic modules  102  for providing haptic outputs. As shown in  FIG.  1   , the electronic device  100  may be a laptop computing device. Although laptop electronic devices are shown in the figures and described below, the haptic modules described herein may be used with various electronic devices including, but not limited to, tablets, mobile phones, personal digital assistants, a time keeping device, a health monitoring device, a wearable electronic device, an input device (e.g., a stylus), a desktop computer, electronic glasses, and so on. Although various electronic devices are mentioned, the haptic modules  102  of the present disclosure may also be used in conjunction with other products and combined with various materials. 
     For example, the haptic modules  102  may be used on a band of a wearable electronic device, a dashboard for an automobile, a steering wheel for an automobile, a housing of an electronic device, a keyboard, and so on. Use of the haptic modules  102  described herein may replace conventional rotary or linear actuators. As a result, the profile of the electronic device may be smaller and/or thinner. 
     The electronic device  100  may include a housing that includes an enclosure component  104  and one or more input mechanisms  106 . In some embodiments, the input mechanisms  106  may be a touch-sensitive input device such as a trackpad, a keyboard, a touch-sensitive display, and so on. The electronic device  100  can include one or more haptic modules  102  that can be coupled to different portions of the housing. For example, as shown in  FIG.  1   , a laptop computing device can include an upper portion  105   a  and a lower portion  105   b.  The upper portion  105   a  can include a first input mechanism  106   a  that functions as a first display and provides visual outputs to a user. In some cases the first input mechanism  106   a  can include a touch sensitive display and receive touch inputs from a user. One or more haptic modules  102  can be coupled to the first input mechanism  106   a  and be configured to provide haptic outputs along the first input mechanism  106   a.    
     The lower portion  105   b  of the laptop can include one or more additional input mechanisms. For example, the lower portion may include a second input mechanism  106   b  that functions as a keyboard and a third input mechanism  106   c  that functions as a track pad. In some cases, the second and third input mechanisms  106   b,    106   c  can be distinct structures. For example, the second input mechanism  106   b  can be a keyboard or a touch-sensitive input device that functions as a keyboard and the third input mechanism  106   c  can be another touch-sensitive input device that functions as a track pad. In this example, the second input mechanism  106   b  may include key regions which can be displayed virtually (e.g., by a display) and/or be physical features of the second input mechanism  106   b  (e.g., physical keys, printed key designations, and so on). The key regions can be configured in a variety of ways such as corresponding to a QWERTY keyboard layout. The second input mechanism  106   b  can include haptic modules  102  that correspond to one or more of the key regions, for example, each haptic module may be positioned below one or more of the designated key regions and be configured to provide localized haptic outputs in the region of the second input mechanism  106   b.  For example, haptic modules positioned below key regions may be configured to provide key haptic feedback to keyboard inputs such as click-type feedback that corresponds to a keystroke input at one or more key regions. Additionally or alternatively, the third input mechanism  106   c  may include a touch-sensitive surface that is configured to detect touch inputs, but may not include a display. One or more haptic modules  102  can also be positioned beneath the third input mechanism  106   c  and be configured to provide localized haptic outputs in the region of the third input mechanism  106   c.    
     In other cases, the lower portion  105   b  can include a single input mechanism such as a touch-sensitive display that displays different regions corresponding to different input structures. For example, the touch-sensitive display may display a key region that is operable as a virtual keyboard and a trackpad region that is operable as a virtual trackpad. In these cases, a first set of haptic modules can include haptic modules  102  that are each positioned beneath one or more key regions and configured to provide localized haptic outputs to keyboard inputs. A second set of haptic modules may include haptic modules  102  that are positioned below the trackpad region and configured to provide localized haptic outputs to the track pad region. 
     In some embodiments, one or more of the input mechanisms  106  may be a touch-sensitive display and configured to determine a location of a touch on an input surface of the corresponding input mechanism  106 . Thus, when a touch sensor detects the location of the touch, an electronic signal may drive one or more haptic modules  102  at the detected location, thereby generating haptic output at that location. 
     The touch sensor may be a capacitive-based touch sensor that is disposed relative to a corresponding input mechanism  106  or a display stack of the electronic device  100 . Although a capacitive-based touch sensor is provided as one example, other types of sensors or sensing arrangements may be used. 
     The electronic device  100  may also include a force-sensing element that uses a force sensor to detect and measure the magnitude of force of a touch on a surface of the electronic device  100 . The surface may be, for example, a display, a keyboard region, a track pad, or some other input mechanism or surface of the electronic device  100 . 
     The haptic modules  102 , as described herein, may be combined or otherwise integrated with the touch sensor or the force sensor and may provide both input and output capabilities. For example, the haptic modules  102  may provide haptic output at or near the location of any detected touch input. The haptic modules  102  may also provide various types of haptic output depending on the detected amount of force. In addition, the haptic modules  102  may be used to detect a received amount of force such as will be described below. 
     The electronic device  100  may include the case  104  that encloses one or more components of the electronic device  100 . The case  104  may also be coupled to or may otherwise incorporate one or more haptic modules  102 . For example, one or more haptic modules  102  may be coupled to the case  104  of the electronic device  100 . 
     In some cases, the haptic modules  102  disclosed herein may also be used in place of the feedback that would normally be produced due to mechanical linkages or components of a physical key or traditional input mechanism. For example, the second input mechanism  106   b  may include a touch sensitive surface that includes a sheet of material that defines a virtual keyboard (e.g., no mechanical keys) and the corresponding haptic modules  102  can provide haptic feedback that simulate the tactile or haptic response of a mechanical key or provide other feedback in response to a touch or press. In other cases, the second input mechanism  106   b  may include mechanical keys or key regions that actuate or move in response to user input (e.g., keystrokes) and the corresponding haptic module  102  can be configured to provide haptic feedback in addition to any feedback provided by the movement of the keys. 
     In one implementation, when a force is received at or near the location of the haptic module  102 , the haptic module  102  may generate an electrical signal (e.g., pulse or other signal having a voltage and/or current) that is measurable by an electronic component of the electronic device  100 . A processing element or sensor circuitry may be responsive to the electrical signal and may recognize the signal as an input. The input may be treated as a binary input (e.g., counted as an input if the charge or current exceeds a threshold) or a variable input that varies over a continuum (e.g., different properties of the signal correspond to different amounts of input or different inputs). 
     To continue the example, the amount of current or voltage generated by the haptic module  102  may vary based on the type of input received. For example, if an amount of current generated or detected is above a first threshold, it may indicate that a first type of touch input is received (e.g., a quick touch or press). If an amount of current generated or detected is above a second threshold, it may indicate that a second type of touch input is received (e.g., a long touch or press). 
     The haptic module  102  may also work in conjunction with one or more force-sensing elements or one or more force sensors to determine an amount of force that is applied to an input surface (or other surface) of the electronic device  100 . In addition, the haptic module  102  may be used to determine the location of the received input, and to determine one or more gestures associated with the received input. For example, if a haptic structure or a series of haptic structures detect a touch input over a certain time period and over a certain distance on a surface of the electronic device  100 , a swipe gesture may be detected. 
       FIG.  2    shows a cross-sectional view of the electronic device  100  taken along section line A-A shown in  FIG.  1   . The cross-sectional view shows an example input mechanism  106  and an example haptic module  102  coupled the input mechanism  106 . The input mechanism  106  can be an example of a touch-sensitive display and include a transparent cover  202  (which may be referred to simply as a “cover”) positioned over a display  204 . The cover  202  and the case  104  along with other components may form a sealed internal volume of the electronic device  100 , which may contain the internal electrical components of the electronic device  100 . In some cases, the cover  202  defines substantially the entire front face and/or front surface of the electronic device  100 . The cover  202  may also define an input surface of the electronic device  100 . For example, as described herein, the electronic device  100  may include touch and/or force sensors that detect inputs applied to the cover  202 . The cover  202  may be formed from or include glass, sapphire, a polymer, a dielectric, or any other suitable material. 
     The display  204  may be positioned under the cover  202  and at least partially within the case  104 . The display  204  may define an output region in which graphical outputs are displayed. Graphical outputs may include graphical user interfaces, user interface elements (e.g., buttons, sliders, etc.), text, lists, photographs, videos, or the like. The display  204  may include a liquid-crystal display (LCD), an organic light emitting diode display (OLED), or any other suitable components or display technology. In some cases, the display  204  may output a graphical user interface with one or more graphical objects that display information. 
     The display  204  may be touch- and/or force-sensitive and include or be associated with touch sensors and/or force sensors that extend along the output region of the display and which may use any suitable sensing elements and/or sensing techniques. Using touch sensors, the electronic device  100  may detect touch inputs applied to the cover  202 , including detecting locations of touch inputs, motions of touch inputs (e.g., the speed, direction, or other parameters of a gesture applied to the cover  202 ), or the like. Using force sensors, the electronic device  100  may detect amounts or magnitudes of force associated with touch events applied to the cover  202 . The touch and/or force sensors may detect various types of user inputs to control or modify the operation of the device, including taps, swipes, multiple finger inputs, single- or multiple-finger touch gestures, presses, and the like. Touch and/or force sensors may be usable with electronic devices, as described herein. 
     The haptic module  102  may include a substrate  206 , a spacer  208 , and a piezoelectric element  210 . The substrate  206  can be positioned below the cover  202  and within an interior of the electronic device  100 . The spacer  208  can couple the substrate  206  to the cover  202 , for example using adhesive layers  212 , which may be any suitable type of adhesive such as a pressure sensitive adhesive. In some cases, an adhesive layer  212  can couple the spacer  208  to a bottom surface of the input mechanism  106 , such as coupling the spacer  208  to a bottom surface of the display  204 . The substrate  206  can be offset from the input mechanism  106  such that there is a gap between the substrate  206  and the input mechanism  106 . In this regard, the spacer  208  may be the only component of the haptic module  102  that is directly coupled to the input mechanism  106 . The substrate  206 , the piezoelectric element  210 , and a flexible circuit  214  may form an actuation strip  205  that is coupled to the input mechanism  106  by the spacer  208 . 
     The piezoelectric element  210  can be positioned on the substrate  206  and offset from the input mechanism  106  such that there is a gap between the piezoelectric element  210  and the input mechanism  106 . The piezoelectric element  210  can be coupled to the substrate  206  and configured to deform the substrate  206  when actuated. In some cases, the piezoelectric element  210  is coupled to an upper surface of the substrate  206  (as shown in  FIG.  2   ). Additionally or alternatively, the piezoelectric element  210  can be coupled to other surfaces of the substrate  206 , such as a bottom surface of the substrate  206  (not shown). 
     The piezoelectric element  210  may be offset from the input mechanism  106  such that it is not directly coupled to the input mechanism  106 . When the piezoelectric element  210  is actuated, it may deform the substrate  206  which causes the movement of the piezoelectric element  210  to be transferred to the input mechanism  106  via the spacer  208 . In this regard, the haptic module may have a structure that reduces the stress/strain between the input mechanism  106  and the piezoelectric element  210  as compared to piezoelectric materials that are directly coupled to the input mechanism  106  (e.g., are configured as a laminated layer within a display stack). For example, when the input mechanism  106  is deformed, for example in response to a touch input, the offset between the piezoelectric element  210  and the input mechanism  106  can reduce the amount of stress that is transferred from the input mechanism  106  and to the piezoelectric element  210 . 
     The haptic module  102  can also include a flexible circuit  214  that electrically couples the piezoelectric element  210  to control components of the electronic device such as a piezo driver circuit, power source, processing unit, or other electronic components that provide inputs to and/or receive outputs from the piezoelectric element  210 . In some cases, the flexible circuit  214  is positioned between the substrate  206  and the piezoelectric element  210  and includes electrical traces and/or other electrical components. In some cases, the flexible circuit  214  can include a polymer substrate such as a polyimide (PI) substrate and the routing traces can be coupled to the polymer substrate. In some embodiments, the flexible circuit  214  can extend from the piezoelectric element  210  and outside the spacer  208 . For example, the flexible circuit  214  can include one or more electrical interfaces such as a zero insertion force (ZIF) interface, hot bar connection, and so on, that is positioned outside the spacer  208  and can be used to electrically couple the flexible circuit  214  to other electrical components of the electronic device  100 . 
     The substrate  206  can be formed from a variety of materials including metals and alloys, polymers, ceramics, or any other suitable material or combinations thereof. In some cases, the substrate  206  is formed from a steel material such as a stainless steel. The spacer  208  can also be formed from a variety of materials including metals and alloys, polymers, ceramics, or any other suitable material or combinations thereof. In some cases, the spacer  208  is formed from molded polymer materials such as polycarbonate materials, polyethylene materials, polyamide materials (nylon), styrene materials, polypropylene materials, polyimide materials, acrylonitrile Butadiene Styrene (ABS) materials, rubbers such as silicone rubbers, combinations thereof, or any other suitable polymer materials. In some cases, the substrate  206  and/or the spacer  208  can include composite polymer materials such as glass filled polymers; carbon, graphite or metal reinforced polymers; or any other suitable composite materials. 
     The piezoelectric element  210  can include any suitable piezoelectric material including lead free piezoelectric materials such as KKN piezoelectric materials, polyvinylidene fluoride (PVDF) or any other suitable lead-free piezoelectric material. In some case, the piezoelectric element  210  can include other piezoelectric materials such as lead zirconate titanate (PZT). The piezoelectric element  210  can be coupled to the substrate  206  using any suitable techniques such as using adhesives, direct bonding, and so on. 
     The deformation properties of the haptic module  102  can be controlled and tuned by a variety of factors including the size (e.g., thickness), shape, materials properties of the substrate  206 , the spacers  208 , and the piezoelectric element  210 . For example, these parameters of the haptic module  102  can be configured to impart a desired amount of deformation at the cover  202  to produce the targeted haptic output. In some cases, the haptic module  102  can be configured to produce deformations in the range of 5-30 microns. In some cases, the thickness of the substrate  206  can be in the range of 0.1-1.0 millimeters, the thickness of the spacer  208  can be in the range of 0.2-1.5 millimeters, and the thickness of the piezoelectric element  210  can be in the range of 0.1-1.0 millimeters. In some cases, the thickness of the piezoelectric element  210  is less than the thickness of the spacer  208 , such that the piezoelectric element  210  is offset from the input mechanism  106 . 
     In some cases, the gap that is formed between the actuation strip and the input mechanism can be filled with a material. For example, this material can be a gel, encapsulant, or other filler that fills the gap, for example to prevent the accumulation of dust or debris. In some cases, this filler material may not significantly affect the bending properties of the actuation strip and/or the input mechanism  106 . For example, the filler material can be more compliant than the actuation strip  205  and/or the input mechanism  106 . 
       FIGS.  3 A- 3 C  show cross-sectional views taken along section line A-A and  FIGS.  4 A- 4 C  show cross-sectional views taken along section line B-B of example neutral and actuated states of the haptic module  102  shown in  FIG.  1   .  FIGS.  3 A and  4 A  show an example of the haptic module  102  in a neutral state when the piezoelectric element  210  is in an inactive state. In the inactive state, the haptic module  102  may act as a passive structure and may move or otherwise deform in response to the input mechanism  106  being deformed, for example in response to a touch input. 
       FIGS.  3 B and  4 B  show an example of the haptic module  102  in a first active state and  FIGS.  3 C and  4 C  shows an example of the haptic module  102  in a second active state. For example, when a first input signal is applied to the piezoelectric element  210 , the piezoelectric element  210  may cause the substrate  206  to have a concave shape which, via the spacer  208 , causes input mechanism  106  to also have a concave shape such as shown in  FIGS.  3 B and  4 B . In some cases, the actuation of the piezoelectric element  210  causes the piezoelectrical element  210  to bend or otherwise deform the substrate  206 , such as in a buckling mode. The bending or deforming of the substrate  206  can cause the spacer  208  to deform the input mechanism  106 . In some cases, the piezoelectric element  210  can shorten or lengthen along a first direction (e.g., length and/or width of the piezoelectric element  210 ), which causes the input mechanism  106  to move in a second direction that is substantially orthogonal to the first direction. In this regard, the spacer  208  transfers the motion of the piezoelectric element  210  to the input mechanism  106 . 
     When a second input signal is applied to the piezoelectric element  210 , the piezoelectric element  210  may cause the substrate  206  to have a convex shape which, via the spacer  208 , causes the input mechanism  106  to have a convex shape such as shown in  FIGS.  3 C and  4 C . Each time the piezoelectric element  210  deflects, a haptic output may be provided. 
     In some embodiments, the piezoelectric element  210  may be driven to produce a discrete haptic output or may be driven to produce a continuous haptic output. Additionally, the piezoelectric element  210  may be driven at a range of frequencies to produce different types and intensities of haptic output. For example, the piezoelectric element  210  may be driven at frequencies of 1 Hz up to 1 kHz or more. 
       FIGS.  5 A and  5 B  show a perspective view of example haptic modules  500 . The haptic modules  500  may be examples of the haptic modules described herein. In the example shown in  FIG.  5 A , the haptic module  500   a  may include a substrate  502   a,  a spacer  504   a,  and a piezoelectric element  506   a.  The spacer  504   a  can extend around the piezoelectric element  506   a.  The spacer  504   a  can couple the substrate  502   a  to an input mechanism (not shown), such as input mechanism  106 . In this regard, the substrate  502   a,  the spacer  504   a,  and the input mechanism may form a cavity that contains the piezoelectric element  506   a.  The piezoelectric element  506   a  may be coupled to the substrate  502   a  and offset from the input mechanism, as described herein. The haptic module  500   a  can include a flexible circuit  508   a  that extends past the end of the substrate  502   a  and electrically couples the haptic module  500   a  to an electronic device, as described herein. In other cases, the flexible circuit  508   a  can extend to the edge of the substrate  502   a,  be contained within the spacer  504   a,  or be arranged in other suitable configurations. 
     In the example shown in  FIG.  5 B , the haptic module  500   b  may include multiple spacer elements  504   b  that are positioned around the piezoelectric element  506   b  and couple the substrate  502   b  to an input mechanism (not shown), such as input mechanism  106 . The spacer elements  504   b  can be configured in a variety of ways including a number of spacer elements  504   b,  lengths, widths, and thicknesses to cause a desired haptic response at the input mechanism. For example, the multiple discrete spacer elements  504   b  may be used to cause the input mechanism to deform in a defined pattern. The haptic module  500   b  can include a flexible circuit  508   b  that extends past the end of the substrate  502   b  and electrically couples the haptic module  500   b  to an electronic device, as described herein. In other cases, the flexible circuit  508   b  can extend to the edge of the substrate  502   a,  or be arranged in other suitable configurations. 
       FIGS.  6 A and  6 B  show perspective views of example haptic modules  600  that include an integrated substrate and spacer structure. The haptic modules  600  can be an example of the haptic modules described herein. For illustration purposes, the haptic modules  600  only show a substrate  602  and a piezoelectric element  604 , however the haptic modules  600  can include other components such as a flexible circuit, coupling mechanisms (e.g., pressure sensitive adhesives), and so on. The haptic modules  600  can be configured to couple to an input mechanism, as described herein. 
     In the example shown in  FIGS.  6 A and  6 B , the haptic modules  600  can include a substrate  602  that includes one or more spacer features  603  (only one labeled for clarity). The substrate  602  can be formed in a variety of ways such as from sheet metal processing procedures (e.g., stamping, binding, and so on); using molding techniques such as injection molding; using machining techniques; or any other suitable process. The piezoelectric element  604  can be coupled to the substrate  602  and the spacer features  603  can offset the piezoelectric element  604  from an input mechanism, as described herein. 
       FIG.  7    shows a top view of a portion of an electronic device  700  that includes haptic modules  706  and touch sensors  708 . The electronic device  700  can be an example of the electronic devices described herein, such as electronic device  100 . The electronic device  700  can have a housing that includes an input mechanism  702  that is coupled to a case  704 . In some cases, the input mechanism  702  can be coupled to the case  704  by a seal  703 , which can be a flexible seal. One or more haptic modules  706  (one of which is labeled for clarity) can be coupled to the input mechanism  702 . One or more touch sensors  708  (one of which is labeled for clarity) can also be coupled to the input mechanism  702 . 
     The touch sensors  708  can be implemented in a variety of ways including capacitive based sensors, strain based sensors, or other suitable touch and/or force sensing techniques. In some cases, the location of a touch input can be used to control outputs at different ones of the haptic modules  706 . For example, a location of a touch can be used to determine a distance to multiple of the haptic modules  706 , and a haptic output generated by each of the haptic modules  706  can be scaled in proportion to its respective distance from the determined location of the touch. In this regard, the haptic modules  706  can each be actuated in a different way to provide a combined haptic output at the input mechanism  702 . In some cases, different drive signals can be supplied to each haptic module  706  to generate different haptic outputs. Various parameters of the drive signals can be varied such as an amplitude, energy, impulse, signal width, frequency, and so on to create different haptic effects at the haptic modules  706 . 
       FIG.  8 A  shows a cross-sectional view of the electronic device  700  taken along section C-C of  FIG.  7   .  FIG.  8 A  shows an example touch sensor  708  structure in which the case  704  functions as a reference electrode and electrodes  710  (one of which is labeled for clarity) function as sensing electrodes. The electrodes  710  can be coupled to the input mechanism  702  and move with the input mechanism  702 . For example, the input mechanism  702  may deform in response to a user touch, and this deformation can change the distance between one or more of the electrodes  710  and the case  704 . Each touch sensor  708  can output a sensor signal that is indicative of this change in distance, and the processing unit can be configured to determine a location of a touch based on one or more of the sensor signals. In some cases, the sensor signals can be used to estimate a force of a touch. For example, the sensor signals can be used to determine a change in distance, which can be used to determine a force of the touch based on one or more calibration factors, a lookup table, the mechanical properties of the input mechanism  702 , or other suitable factors, or a combination thereof. Additionally or alternatively, the sensor signals can be used to determine a location of a touch. For example, a strength of an electrical response of multiple ones of the touch sensors  708  can be used to interpolate or otherwise determine the position of a touch input. 
     In some cases, the case  704  can define an opening  705  and the haptic module  706  can be aligned and/or positioned in the opening  705 . Accordingly, as the input mechanism  702  is deformed, the haptic module  706  can move with respect to the case  704  without contacting the case  704  or other internal components. In some cases, the opening  705  may help reduce the amount of space required for the haptic module  706  and help decrease the overall stack height of the haptic module  706  and/or input mechanism  702 . 
     Additionally or alternatively, the seal  703  can be configured to function as a force sensor that can detect touches to the input mechanism  702 . In some cases, the seal  703  can be configured as a capacitive-based sensor, a resistive-based sensor, or other suitable sensor. For example, the seal  703  can include a flexible component that separates opposing electrodes (not shown). The seal  703  can deform in response to a touch to the input mechanism  702  and the opposing electrode can output a signal that is used to determine a location of the touch and/or estimate a force of the touch. 
       FIG.  8 B  shows a cross-sectional view of the electronic device  700  taken along section C-C of  FIG.  7   .  FIG.  8 B  shows another example touch sensor  712  structure that includes a reference electrode  714  and sensing electrodes  710  (one of which is labeled for clarity). The sensing electrodes  710  can be coupled to the input mechanism  702  and move with the input mechanism  702 . The reference electrode  714  can be coupled to the case  704  and configured to remain stationary with respect to the input mechanism  702 . For example, the input mechanism  702  may deform in response to a user touch, and this deformation can change the distance between one or more of the electrodes  710  and the reference electrode  714 . Each touch sensor  712  can output a sensor signal that is indicative of this change in distance, and the processing unit can be configured to determine a location and/or force of a touch based on one or more of the sensor signals, as described herein. 
     In some cases, the reference electrode  714  can be coupled to the case  704  by the seal  703 . The case  704  can define a first opening  705  and the reference electrode  714  and/or the haptic module  706  can be aligned with and/or positioned within the first opening  705 . Additionally or alternatively, the reference electrode  714  can define one or more second openings  707  (one of which is shown for clarity) and the haptic module  706  can be aligned with and/or positioned within the second opening  707 . In this regard, the first opening  705  and/or the second opening  707  may reduce the overall stack height of the haptic module  706  by allowing the haptic module  706  to move within the first opening  705  and/or the second opening  707  as it is deformed and/or actuated. 
       FIG.  9 A  shows a top view of a portion of an electronic device  900  that includes haptic modules  906  and touch sensors (shown in  FIG.  9 B ). The electronic device  900  can be an example of the electronic devices described herein, such as electronic device  100 . The electronic device  900  can have a housing that includes an input mechanism  902  that is coupled to a case  904 . In some cases, the input mechanism  902  can be coupled to the case  904  by a seal  903 , which can be a flexible seal, as described herein. One or more haptic modules  906  (one of which is labeled for clarity) can be coupled to the input mechanism  902 . A touch and/or force sensor can be integrated into the input mechanism  902  as illustrated in  FIG.  9 B . 
       FIG.  9 B  shows a cross-sectional view of the electronic device  900  taken along section D-D of  FIG.  9 A . The input mechanism  902  can be an example of the input mechanisms described herein and includes a cover  908 , an electrode layer  909 , a compliant layer  910 , and a first substrate  912 .The haptic module  906  can be coupled beneath the input mechanism  902 . The haptic module  906  can be an example of the haptic modules described herein and includes a second substrate  914 , a spacer  916 , and a piezoelectric element  918 . 
     The input mechanism  902  can be configured to determine a location of a touch and/or estimate a force of the touch based on changes in thickness of the compliant layer  910 . For example, a touch input on the cover  908  can cause the compliant layer  910  to compress. The first substrate  912  can be configured to remain substantially undeformed and the electrode layer  909  can deform with the compliant layer  910  and towards the first substate. In this regard the input mechanism  902  can be configured to output one or more signals that are indicative of the change in distance between the electrode layer  909  and the first substrate  912 . In some cases, the electrode layer  909  can include an array of individual electrodes that each output a signal that is indicative of the change in distance between the respective electrode and the first substrate  912 . 
     The cover  908  can be an example of the covers described herein and be formed from a transparent material. The input mechanism  902  can also include a display  911  which can be an example of the displays described herein. 
     In some cases, the compliant layer  910  includes an array of flexible structures that are positioned between the cover  908  and the first substrate  912 . For example, the flexible structures can be an array of discrete elastomeric columns such as a gel-dot array that maintains the cover  908  and the first substrate  912  at a separation distance when no touch input is present and compress to reduce the distance between the cover  908  and the first substrate  912  in response to a touch input. The first substrate  912  can be formed from a variety of materials including metals and alloys, polymers, ceramics, or any other suitable material or combinations thereof. 
     The haptic module  906  may be configured to cause a haptic output at the cover  908  by deflecting the input mechanism  902 . In this regard, the haptic module  906  can be configured to cause the first substrate  912 , the display  911 , the compliant layer  910 , the electrode layer  909 , and the cover  908  to deflect when the piezoelectric element  918  is actuated. 
       FIG.  10    is an example block diagram of an electronic device  1000  including haptic structures for providing haptic outputs, which can take the form of any of the devices as described with reference to  FIGS.  1 - 9   . The electronic device  1000  can include a processor  1002 , an input/output (I/O) mechanism  1004  (e.g., wired or wireless communications interfaces), a display  1006 , memory  1008 , sensors  1010  (e.g., touch and/or force sensors), and a power source  1012  (e.g., a rechargeable battery). The processor  1002  can control some or all of the operations of the electronic device  1000 . The processor  1002  can communicate, either directly or indirectly, with some or all of the components of the electronic device  1000 . For example, a system bus or other communication mechanism  1014  can provide communication between the processor  1002 , the I/O mechanism  1004 , the memory  1008 , the sensors  1010 , and the power source  1012 . 
     The processor  1002  can be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor  1002  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 suitable computing element or elements. 
     It should be noted that the components of the electronic device  1000  can be controlled by multiple processors. For example, select components of the electronic device  1000  (e.g., a sensor  1010 ) may be controlled by a first processor and other components of the electronic device  1000  and other components of the electronic device  1000  (e.g., the I/O  1004 ) may be controlled by a second processor, where the first and second processors may or may not be in communication with each other. 
     The I/O device  1004  can transmit and/or receive data from a user or another electronic device. An I/O device 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. In some cases, the I/O device  1004  can communicate with an external electronic device, such as a smartphone, smartwatch, or other portable electronic device, as described here. 
     The electronic device may optionally include a display  1006  such as a liquid-crystal display (LCD), an organic light emitting diode (OLED) display, a light emitting diode (LED) display, or the like. If the display  1006  is an LCD, the display  1006  may also include a backlight component that can be controlled to provide variable levels of display brightness. If the display  1006  is an OLED or LED type display, the brightness of the display  1006  may be controlled by modifying the electrical signals that are provided to display elements. The display  1006  may correspond to any of the displays shown or described herein. 
     The memory  1008  can store electronic data that can be used by the electronic device  1000 . For example, the memory  1008  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  1008  can be configured as any type of memory. By way of example only, the memory  1008  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  1000  may also include one or more sensors  1010  positioned almost anywhere on the electronic device  1000 . The sensor(s)  1010  can be configured to sense one or more types of parameters, such as but not limited to, pressure, light, touch, heat, movement, relative motion, biometric data (e.g., biological parameters), and so on. For example, the sensor(s)  1010  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  1010  can utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasound, piezoelectric, and thermal sensing technology. 
     The power source  1012  can be implemented with any device capable of providing energy to the electronic device  1000 . For example, the power source  1012  may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power source  1012  can be a power connector or power cord that connects the electronic device  1000  to another power source, such as a wall outlet. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of 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.