PATENT DOCUMENT

Publication Number: US-11809631-B2
Application Number: US-202217855236-A
Country: US
Kind Code: B2

Title: Reluctance haptic engine for an electronic device

Abstract:
A reluctance haptic engine for an electronic device includes a core, an attractor plate, and mechanical suspension. The core and/or the attractor plate may be coupled to an input structure, such as a button cap, a trackpad cover, or a touchscreen cover. In an unactuated configuration, flexible support members maintain a gap between the core and the attractor plate. An electrical current may be applied to one or more conduction loops of the core to actuate the reluctance haptic engine and provide a haptic output by moving the input structure. The electrical current may cause a magnetic flux that results in a reluctance force that pulls the attractor and the core together and causes the input structure to move to produce a haptic output.

Claims:
What is claimed is: 
     
         1 . An electronic device comprising:
 a housing defining an opening;   an input structure positioned at least partially within the opening and moveable with respect to the housing, the input structure defining an input surface;   a reluctance haptic engine positioned beneath the input structure and comprising:
 a core affixed to a bottom surface of the housing and comprising a conduction loop operable to receive an electrical signal; 
 an attractor plate separated from the core by a first gap and separated from a frame coupled to the housing by a second gap; and 
 a mechanical suspension coupling the attractor plate to the input structure and securing the attractor plate and the input structure to the housing; and 
   a processor configured to cause the core to generate a reluctance force by providing the electrical signal to the conduction loop, the generation of the reluctance force causing the attractor plate to move toward the core, thereby deforming the mechanical suspension, reducing the first gap between the attractor plate and the core, increasing the second gap between the attractor plate and the frame, and applying the reluctance force to the input structure.   
     
     
         2 . The electronic device of  claim 1 , wherein:
 the mechanical suspension comprises a sensing element that detects an input applied to the input structure; and   the processor provides the electrical signal to the conduction loop in response to the detection of an input force.   
     
     
         3 . The electronic device of  claim 2 , wherein:
 the input comprises the input force that is applied to the input structure in a first direction;   the reluctance force is applied to the input structure in a second direction; and   the first direction is opposite from the second direction.   
     
     
         4 . The electronic device of  claim 1 , wherein the reluctance force extends the input structure above the housing. 
     
     
         5 . The electronic device of  claim 1 , further comprising one or more spacers coupling the mechanical suspension to the housing, wherein the input structure further defines one or more support structures that extend through the housing and couple with the mechanical suspension. 
     
     
         6 . The electronic device of  claim 1 , wherein, in response to an input applied to the input structure:
 the first gap between the attractor plate and the core increases; and   the second gap between the attractor plate and the frame decreases.   
     
     
         7 . The electronic device of  claim 6 , wherein, in response to the reluctance force being applied subsequent to the input, the reluctance force causes:
 the first gap between the attractor plate and the core to decrease; and   the second gap between the attractor plate and the frame to increase.   
     
     
         8 . The electronic device of  claim 7 , wherein:
 the electronic device is a laptop computer; and   the input structure is a touch strip of the laptop computer.   
     
     
         9 . An electronic device comprising:
 a housing;   a display positioned at least partially within the housing;   an input structure positioned at least partially within the housing; and   a reluctance haptic engine positioned below the input structure and comprising:
 an attractor plate coupled to the housing; and 
 a core comprising a conduction loop and coupled to the input structure, the core separated from the attractor plate by a gap and configured to move toward the attractor plate in response to a reluctance force produced during an actuated state, thereby raising the input structure above the housing. 
   
     
     
         10 . The electronic device of  claim 9 , wherein the actuated state is engaged when the conduction loop of the core receives an electrical signal. 
     
     
         11 . The electronic device of  claim 9 , further comprising one or more flexible members coupling the input structure to the housing and to the core. 
     
     
         12 . The electronic device of  claim 11 , wherein the one or more flexible members deform when the actuated state is engaged. 
     
     
         13 . The electronic device of  claim 9 , further comprising a frame extending beneath the reluctance haptic engine, wherein:
 the gap between the attractor plate and the core is a first gap; and   the core is separated from the frame by a second gap.   
     
     
         14 . The electronic device of  claim 13 , wherein, when an input is applied to the input structure:
 the first gap between the attractor plate and the core increases; and   the second gap between the core and the frame decreases.   
     
     
         15 . The electronic device of  claim 13 , wherein, in response to the reluctance force being produced during the actuated state:
 the first gap between the attractor plate and the core decreases; and   the second gap between the core and the frame increases.   
     
     
         16 . The electronic device of  claim 9 , wherein a user input applied to the input structure moves the core in a first direction opposite from a second direction that the core moves in response to the reluctance force. 
     
     
         17 . A method of producing a haptic output at an electronic device, the method comprising:
 detecting an input at an input structure;   determining, in response to detecting the input, output characteristics of the haptic output to be generated by a reluctance haptic engine;   generating an output signal corresponding to the determined output characteristics; and   applying an electrical signal to a core of the reluctance haptic engine to generate a reluctance force, the reluctance force opposing the input.   
     
     
         18 . The method of  claim 17 , wherein the output characteristics include at least one of a force value of the reluctance force, a location of the reluctance force, or a rotational speed associated with the reluctance force. 
     
     
         19 . The method of  claim 17 , wherein detecting the input at the input structure comprises detecting one of a force value, an intensity, or a location of the input. 
     
     
         20 . The method of  claim 17 , wherein the haptic output is a local haptic output applied to the input structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a nonprovisional and claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Pat. Application No. 63/246,432, filed Sep. 21, 2021, the contents of which are incorporated herein by reference as if fully disclosed herein. 
    
    
     FIELD 
     Embodiments relate generally to an electronic watch or other electronic device. More particularly, the described embodiments relate to a reluctance actuator configured to provide a haptic output for an electronic device. 
     BACKGROUND 
     Modern electronic devices commonly include a number of output devices to provide feedback or information to a user. One type of output device is a haptic actuator which is used to provide a haptic output, such as an impulse or a vibration, to a user. Haptic output may be provided in response to operations of an electronic device, such as when a user account receives an electronic message. 
     Traditional haptic output devices include motors and other relatively large actuation mechanisms, which occupy significant space within device enclosures. These actuation mechanisms may additionally require a relatively large amount of energy, resulting in decreased battery life. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in simplified form that are further described herein. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In various embodiments of the provided disclosure, a reluctance haptic engine may be used to provide a haptic signal. The reluctance haptic engine may be configured such that a direction of a haptic force opposes a corresponding input force. In accordance with this arrangement, additive forces may be minimized or avoided. Additional features will become apparent with reference to the provided disclosure. 
     In some embodiments, an electronic device may be provided. The electronic device may comprise a housing defining an opening, an input structure positioned at least partially within the opening and moveable with respect to the housing, the input structure defining an input surface, and a reluctance haptic engine. The reluctance haptic engine may be positioned beneath the input structure and may comprise a core affixed to a bottom surface of the housing and comprising a conduction loop operable to receive an electrical signal, an attractor plate separated from the core by a first gap and separated from a frame coupled to the housing by a second gap, and a mechanical suspension coupling the attractor plate to the input structure and securing the attractor plate and the input structure to the housing. The electronic device may further comprise a processor configured to cause the core to generate a reluctance force by providing the electrical signal to the conduction loop, the generation of the reluctance force causing the attractor plate to move toward the core, thereby deforming the mechanical suspension, reducing the first gap between the attractor plate and the core, increasing the second gap between the attractor plate and the frame, and applying the reluctance force to the input structure. 
     In some implementations, the mechanical suspension may comprise a sensing element that detects an input applied to the input structure and the processor may provide the electrical signal to the conduction loop in response to the detection of the input force. An input may comprise an input force that is applied to the input structure in a first direction. A reluctance force may be applied to the input structure in a second direction and the first direction may be opposite from the second direction. In some cases, the reluctance force may extend the input structure above the housing. 
     According to some embodiments, an electronic device may further comprise one or more spacers coupling the mechanical suspension to the housing. The input structure may further define one or more support structures that extend through the housing and couple with the mechanical suspension. In response to an input applied to the input structure, a first gap between the attractor plate and the core may increase and the second gap between the attractor plate and the frame may decrease. In response to the reluctance force, the first gap between the attractor plate and the core may decrease and the second gap between the attractor plate and the frame may increase. An electronic device may be a laptop computer and an input structure may be a touch strip of a laptop computer. 
     According to some implementations, an electronic device may be provided. The electronic device may comprise a housing, a display positioned at least partially within the housing, an input structure positioned at least partially within the housing, and a reluctance haptic engine positioned below the input structure. The reluctance haptic engine may comprise an attractor plate coupled to the housing and a core comprising a conduction loop and coupled to the input structure. The core may be separated from the attractor plate by a gap and may be configured to move toward the attractor plate in response to a reluctance force produced during an actuated state, thereby raising the input structure above the housing. 
     An actuated state may be engaged when the conduction loop of the core receives an electrical signal. An electronic device may further comprise one or more flexible members coupling the input structure to the housing and to the core. The one or more flexible members may deform when the actuated state is engaged. 
     In some cases an electronic device may further comprise a frame extending beneath the reluctance haptic engine. A gap between the attractor plate and the core may be a first gap and the core may be separated from the frame by a second gap. 
     When an input is applied to an input structure, the first gap between the attractor plate and the core may increase and the second gap between the core and the frame may decrease. In response to the reluctance force being produced during the actuated state, the first gap between the attractor plate and the core may decrease and the second gap between the core and the frame may increase. A user input applied to the input structure may move the core in a first direction opposite from a second direction that the core may move in response to the reluctance force. 
     In some implementations, a method of producing a haptic output at an electronic device may be provided. The method may comprise detecting an input at an input structure, determining, in response to detecting the input, output characteristics of the haptic output to be generated by a reluctance haptic engine, generating an output signal corresponding to the determined output characteristics, and applying an electrical signal to a core of the reluctance haptic engine to generate a reluctance force, the reluctance force opposing the input. 
     In some cases the output characteristics may include at least one of a force value of the reluctance force, a location of the reluctance force, or a rotational speed associated with the reluctance force. Detecting the input at the input structure may comprise detecting one of a force value, an intensity, or a location of the input. The haptic output may be a local haptic output applied to the input structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to representative embodiments illustrated in the accompanying figures. It should be understood that the following descriptions are not intended to limit the embodiments to one or more preferred embodiments. To the contrary, they are intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments as defined by the appended claims. Similar reference numerals have been used, where practicable, to designate similar features. 
         FIGS.  1 A- 1 B  depict functional block diagrams of an example electronic device that incorporates a reluctance haptic engine with flexible support members, as described herein. 
         FIGS.  2 A- 2 C  illustrate an example electronic device that may incorporate a reluctance haptic engine with flexible support members and having a stationary core comprising one or more conduction loops, as described herein. 
         FIGS.  3 A- 3 B  illustrate partial cross-section views of an electronic device that may incorporate a reluctance haptic engine with flexible support members and having a moveable core comprising one or more conduction loops, as described herein. 
         FIGS.  4 A- 4 E  illustrate an example reluctance haptic engine as may be implemented with respect to an input region operable to receive touch inputs from a user, as described herein. 
         FIG.  5    depicts a flowchart of an example method for producing a haptic output at an electronic device using a reluctance haptic engine with flexible support members, as described herein. 
         FIG.  6    illustrates an example electronic device, configured as an electronic watch, that may incorporate a reluctance haptic engine with flexible support members, as described herein. 
         FIG.  7    depicts a sample electrical block diagram of an electronic device that may incorporate a reluctance haptic engine, as described herein. 
     
    
    
     The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures. 
     Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     The embodiments described herein are directed to an electronic device having a reluctance haptic engine configured to provide haptic output to a user of the electronic device. In various embodiments, the reluctance haptic engine includes a core and an attractor plate. The core and/or the attractor plate may be coupled to an input structure, such as a button cap, trackpad cover, touchscreen cover, and so on. In an unactuated configuration, flexible support members maintain a gap between the core and the attractor plate. An electrical current may be applied to one or more conduction loops of the core to actuate the reluctance haptic engine and provide a haptic output by moving the input structure. The electrical current may cause a magnetic flux resulting in a reluctance force that pulls the attractor and the core together and causes the input structure to move (e.g., translate, rotate, oscillate, vibrate, or deform) to produce a haptic output. In an actuated configuration, a biasing force applied by the flexible support members to maintain the gap may be overcome by the reluctance force, and the gap between the core and the attractor plate is reduced or closed. 
     Some of the embodiments herein are directed to a reluctance haptic engine that provides a force (e.g., an engine force) that opposes a user input force. For example, a user may impart an input force to an input device such as a button. The input force may cause the button to depress, or otherwise move, with respect to an associated housing. The reluctance haptic engine may, in response to detecting the input force, impart an engine force in a direction opposite from the user input force. As will become apparent throughout the disclosure, the engine force may at least partially offset the user input force. 
     The movement of the attractor plate and/or the core may result in deflection and/or deformation of one or more of the flexible support members. For example, the flexible support members may transition from a non-deformed state to a deformed state or from a deformed state to a further-deformed state under the applied reluctance force, resulting in and/or allowing the movement of the attractor plate toward the core and/or allowing the movement of the core toward the attractor plate. When the electrical currents applied to the one or more conduction loops are reduced or ceased, the biasing force of the flexible support members may overcome the reluctance force and cause the biasing members to transition from a deformed state to the non-deformed state (or from a deformed state to a less-deformed state), thereby separating the actuator plate and the core (e.g., moving the actuator away from the core) and/or reestablishing the gap. 
     As used herein, the terms “deform” or “deformation” may be used to refer to any change in shape or form of a component, including as a result of bending, torsion, tensile forces shear forces, compressive forces, or the like. As used herein, the terms “deflect” or “deflection” may refer to displacement of a component or a portion thereof from one position to another. 
     In some cases, the reluctance haptic engine may be used to detect inputs to the electronic device. The flexible support members may deflect or deform in response to a force applied to the input structure, for example by a user input. The flexible support members may include one or more sensing elements that may be used to sense inputs based on measuring deflection and/or deformation of the flexible support members. For example, the sensing elements may include one or more strain sensors positioned along the flexible support members and configured to output a signal that varies based on the deflection and/or deformation of the flexible support members. 
     In some cases, the signals provided by the sensing elements may be used to determine spatial parameters of the attractor plate, the core, and/or the input structure. The spatial parameters may include, but are not limited to, a position, displacement, velocity, and acceleration. The spatial parameters determined from the signals provided by the sensing elements may be used to determine a location and/or magnitude (e.g., force measurement) of an input to the input member. For example, a location and/or magnitude of an input may be determined by determining a difference between output signals of two or more sensing elements. The magnitude of one or more output signals may be used to estimate a magnitude of force applied to the input member. 
     A first flexible support member may be coupled to a first side of the core, and a second flexible support member may be coupled to a second side of the core that is opposite the first side. Positioning the flexible support members on opposite sides of the core may provide enhanced stability for the attractor plate and/or the core and may allow the sensing elements positioned along the flexible support members to more effectively be used to detect the locations and/or magnitudes of inputs and/or feedback related to haptic outputs. 
     As used herein, the terms “haptic output” and “tactile output” may refer to outputs produced by the electronic device that may be perceived through user touch. Examples of haptic outputs include vibrations, deflections, and other movements of a device enclosure, a device cover, or input device, or another device component that forms an input surface of the electronic device. In some cases, a reluctance haptic engine may vibrate, displace, and/or deflect a device component (e.g., an enclosure, a cover, or an input device) to produce a haptic output at an external surface of the device defined by the device component. In some cases, haptic outputs may be produced by relative movement of one or more device components with respect to one or more additional device components. As one example, a reluctance haptic engine may cause a first device component (for example, a cover) to vibrate, oscillate, rotate and/or translate relative to another device component (for example, an enclosure) to produce a haptic output that may be perceived by a user. 
     In various embodiments, an input to a reluctance haptic engine (e.g., an input to an input device as discussed herein) may be detected by the reluctance haptic engine through self-inductance properties of electrically conductive coils of a core of the reluctance haptic engine. As depicted throughout, a gap between a core and an attractor plate may increase in response to a user input (e.g., to the input device). As a result of the increase in the gap, a magnetic flux stimulated by a current associated with the electrically conductive coils may decrease. An inductance associated with the electrically conductive coils may similarly decrease in response to an increasing gap between the core and the attractor plate. By detecting these properties, an input may be detected. 
     In some cases, the reluctance haptic engine is coupled to an enclosure of the electronic device and provides haptic outputs that may be tactilely perceived by the user along one or more portions of an external surface (such as an input or output surface) of the electronic device. In some cases, the reluctance haptic engine is coupled to a contact member that moves (e.g., oscillates, vibrates, translates or rotates) with respect to other components of the electronic device, such as a housing member, to provide haptic outputs. Translation may include inward and outward translation, lateral translation, and other movement of the contact member. In some cases, the reluctance haptic engine provides haptic outputs by deflecting a portion of an enclosure of the electronic device. Different types of movement may be used to provide different haptic outputs. 
     In some cases, the haptic outputs described herein are localized haptic outputs. As used herein, the term “localized haptic output” may be used to refer to a haptic output that is outputted through or at a particular location or region along a particular external surface of the electronic device, such as at an input surface or a portion thereof, while being imperceptible or absent from other external surfaces (or another portion of the particular external surface). The reluctance haptic engines described herein may produce localized haptic outputs causing vibration, deflection, or movement at particular locations or regions of the external surfaces of the electronic device. In some cases, a localized haptic output may be felt strongly at one or more locations or regions of the external surfaces and may be imperceptible or less perceptible at one or more other locations or regions of the external surfaces of the electronic device. 
     In some cases, localized haptic outputs may provide feedback regarding inputs received at particular locations of the electronic device. For example, localized haptic outputs may be provided at and/or near an input device (e.g., a button, a key, a crown, a trackpad, or a touchscreen) to provide feedback related to an input provided at the input device. In other cases, localized haptic outputs may provide other types of feedback or information to users. 
     In some cases, the haptic outputs described herein are global haptic outputs. As used herein, the term “global haptic output” may refer to a haptic output that is produced in a large area and, in some cases, across or through substantially all of the electronic device. As described herein, a reluctance haptic engine may cause a mass or weighted member to move and, in some cases, oscillate, to produce a perceptible vibration or tactile effect along the external surfaces of the electronic device. In general, global haptic outputs are not localized to any particular location or region of the external surfaces of the electronic device. In some cases, global haptic outputs may provide feedback that is not related to a specific location on the electronic device. For example, global haptic outputs may be provided for alerts received at the electronic device. In other cases, global haptic outputs may provide other types of feedback or information to users. 
     The term “attached,” as used herein, may be used to refer to two or more elements, structures, objects, components, parts, or the like that are physically affixed, fastened, and/or retained to one another. The term “coupled,” as used herein, may be used to refer to two or more elements, structures, objects, components, parts, or the like that are physically attached to one another, operate with one another, communicate with one another, are in electrical connection with one another, and/or otherwise interact with one another. Accordingly, while elements attached to one another are coupled to one another, the reverse is not required. As used herein, “operably coupled” or “electrically coupled” may be used to refer to two or more devices that are coupled in any suitable manner for operation and/or communication, including wired, wirelessly, or some combination thereof. 
     These and other embodiments are discussed with reference to  FIGS.  1 A- 7   . 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. 
       FIGS.  1 A- 1 B  depict functional block diagrams of an example electronic device  100  that incorporates a reluctance haptic engine  101 . The electronic device  100  may include a housing  102 , otherwise referenced as a device enclosure or simply “enclosure,” a reluctance haptic engine  101 , one or more input devices  128 , one or more output devices  132 , a display  134 , and a processing unit  130  positioned at least partially within the housing  102 . 
     The reluctance haptic engine  101  may be positioned at least partially within the housing  102  of the electronic device  100  and may be configured to provide haptic outputs along an external surface (e.g., an input surface  108 ) of the electronic device  100 . In various embodiments, the reluctance haptic engine  101  may provide localized haptic outputs at particular locations or regions of the external surfaces of the electronic device  100 . In some cases, the reluctance haptic engine  101  may provide global haptic outputs along the external surfaces of the electronic device. 
     In some cases, as shown in  FIGS.  1 A- 1 B , the reluctance haptic engine  101  may be positioned beneath and/or coupled to an input structure  106  that defines an input surface  108  of the electronic device  100 . The input structure  106  may be a portion of a device housing or cover, such as a top case of a laptop computer. In some cases, the input structure  106  is at least a portion of an input device  128 , such as a button, crown, trackpad, key, or the like. For example, the input structure  106  may be a button cap, a keycap, a trackpad cover, a crown body, and so on. In some cases, the input structure  106  is a cover positioned over a display  134 , such as a touchscreen display. In some cases, the input structure  106  is a portion of the housing  102  of the electronic device  100  and is continuous with one or more additional portions of the housing  102 . Inputs received at the input surface  108  and/or haptic outputs provided at the input surface  108  by the reluctance haptic engine  101  may cause the input structure  106  or portions thereof to deform or deflect with respect to other portions of the input structure  106  and/or other portions of the components defining the external surfaces of the electronic device  100 . 
     In some cases, the input structure  106  may be a separate component from one or more portions of the housing  102 . In some cases, the housing  102  and the input structure  106  cooperate to define at least part of the external surfaces of the electronic device  100 . In some cases, the input structure  106  is positioned in an opening  104  defined by the housing  102 . The input structure  106  may be configured to move (e.g., rotate, translate, or the like) relative to one or more additional components of the electronic device  100 , such as the housing  102 . For example, the input structure  106  may be configured to translate inward and outward (e.g., up and down with respect to  FIGS.  1 A- 1 B ) with respect to the housing  102 . Inputs received at the input surface  108  and/or haptic outputs provided at the input surface  108  by the reluctance haptic engine  101  may cause the input structure  106  or portions thereof to move (e.g., translate, rotate, or the like), deform, or deflect with respect to other portions of the input structure and/or other portions of the components defining the external surfaces of the electronic device. 
     In some cases, the reluctance haptic engine  101  is positioned beneath a structure that is not a portion of an input device (e.g., a portion of the housing  102 ) and/or the reluctance haptic engine  101  provides haptic outputs at one or more surfaces that are not input surfaces. 
     The reluctance haptic engine  101  may include an attractor plate  112  and a core  122 . The attractor plate  112  may be coupled to the core  122  by one or more flexible support members  118   a / 118   b . The one or more flexible support members  118   a / 118   b  may include any mechanical suspension structure, such as a metallic flexure, an elastic gel structure, a wire mesh, any combination thereof, and so on. The flexible support members  118   a / 118   b  may be formed of a compliant or bendable material that allows the relative movement between the attractor plate  112  and the core  122 .  FIG.  1 A  depicts the reluctance haptic engine  101  in an unactuated configuration in which the attractor plate  112  and the core  122  are spaced apart by a gap  126 . In some cases, the flexible support members  118   a / 118   b  may provide a biasing force to maintain the gap  126  between the attractor plate  112  and the core  122  (e.g., in the absence of an electrical current in the conduction loops  124 ). 
     The reluctance haptic engine  101  may include one or more spacers (e.g., spacers  116   a / 116   b ) between the flexible support members  118   a / 118   b  and the attractor plate  112  and/or the core  122  that help to define the gap  126 .  FIG.  1 B  depicts the reluctance haptic engine  101  in an actuated configuration in which the gap  126  between the attractor plate  112  and the core  122  is reduced or eliminated. The reluctance haptic engine  101  may actuate (e.g., transition from an unactuated configuration to an actuated configuration) in response to a reluctance force generated within the reluctance haptic engine. This reluctance force may be generated in response to a force applied to the reluctance haptic engine  101  and/or the input structure  106 , such as by a user input on the input surface  108  of the input structure  106 . 
     The core  122  may include one or more conduction loops  124  (e.g., electromagnetic coils, electrically conductive coils, wire loops, or other electrically conductive materials). Electrical currents (e.g., alternating current, electromagnetic signals, or drive signals) induced in the conduction loops  124  may generate magnetic flux. The magnetic flux passing through the attractor plate  112  and/or the core  122  causes a reluctance force that results in attraction between the attractor plate  112  and the core  122 . As depicted in  FIG.  1 B , the attraction may result in displacement of the attractor plate  112  toward the core  122 , reducing or closing the gap  126  and thereby displacing at least a portion of the input surface  108  away from the attractor plate  112  (e.g., above a surface of the housing  102 ) to produce the haptic output. Actuation of the reluctance haptic engine  101  may produce a haptic output or a portion thereof. The haptic output may be localized along at least a portion of the input structure  106  and/or a global haptic output along a larger portion or a substantial entirety of the housing  102 . 
     As depicted in  FIG.  1 B , actuation of the reluctance haptic engine  101  may be accompanied by deformation of one or more of the flexible support members  118   a / 118   b . During the transition from the unactuated configuration to the actuated configuration of the reluctance haptic engine  101 , the flexible support members  118   a / 118   b  may deform as the gap  126  between the attractor plate  112  and the core  122  is reduced. That is, the flexible support members  118   a / 118   b  may transition from a non-deformed state (e.g., as depicted in  FIG.  1 A ) to a deformed state (e.g., as depicted in  FIG.  1 B ), or from a deformed state to a further-deformed state, as a result of the applied reluctance force, in accordance with the displacement of the core  122  toward the attractor plate  112 . 
     When the reluctance force is reduced or ceased (e.g., when the electrical currents applied to the conduction loops  124  are reduced or ceased) or when the input force is reduced or ceased, the biasing force of the flexible support members  118   a / 118   b  may overcome the reluctance force and/or the input force and cause the biasing members to transition from a deformed state to the non-deformed state (or from a deformed state to a less-deformed state), thereby displacing the core  122  away from the attractor plate  112  and/or reestablishing the gap  126 . Displacing the core  122  away from the attractor plate  112  may produce a haptic output or a portion thereof. 
     The attractor plate  112  may be attached or otherwise coupled to a frame  110  extending from the housing  102 . The frame  110  may be affixed, or otherwise coupled, to the housing  102  and may be immobile with respect to the housing  102 . The core  122  may be moveable with respect to the housing  102  such that the core  122  moves in accordance with an attraction force between the attractor plate  112  and the core  122 . The core  122  may move relative to the attractor plate  112 , the frame  110 , and/or the housing  102 . The displacement of the core  122  may cause a corresponding movement and/or deformation of the portion of the input surface  108  defined by the input structure  106 . For example, as shown in  FIG.  1 B , the input surface  108  may be displaced upward, or away from the attractor plate  112 , as the core  122  moves toward the attractor plate  112 . In some cases, the reluctance haptic engine  101  is coupled to the input structure  106  by one or more connection elements  114 . The connection elements  114  may transfer motion from the reluctance haptic engine  101  to the input structure  106 , thereby producing a haptic output along or through the input surface  108 . The connection elements  114  may extend through the frame  110  and/or the attractor plate  112  and may couple the input structure  106  with the flexible support members  118   a / 118   b , as depicted in  FIGS.  1 A- 1 B . 
     In various embodiments, the positions of the attractor plate  112  and the core  122  may be reversed from what is shown in  FIGS.  1 A- 1 B . For example, the core  122  may be attached or otherwise coupled to the frame  110 , and the attractor plate  112  may be attached or otherwise coupled to the connection elements  114 , such that movement of the attractor plate  112  relative to the core  122 , the frame  110 , and/or the housing  102  causes a corresponding displacement and/or deformation of the portion of the input surface  108  defined by the input structure  106 . As such, while the examples described herein describe displacement of the core  122 , they are additionally meant to encompass examples in which the attractor plate  112  is displaced. 
     The reluctance haptic engine  101  may provide a haptic output by deflecting or deforming a portion of the housing  102 . For example, the reluctance haptic engine  101  may deflect or displace a portion of the housing  102  inward and/or outward to provide a haptic output at the input surface  108 . Deflection or other movement of the housing  102  against a user’s skin, or other object, may produce a haptic output that can be perceived by the user. 
     The reluctance haptic engine  101  may provide a haptic output by oscillating, vibrating, translating, and/or rotating a component of the electronic device  100  relative to other components of the electronic device  100 . For example, the reluctance haptic engine  101  may cause the input structure  106  to move relative to one or more other portions of the housing  102  of the electronic device  100 . The movement of the input structure  106  may be inward (e.g., downward with respect to  FIGS.  1 A- 1 B ), outward (e.g., upward with respect to  FIGS.  1 A- 1 B ), lateral (e.g., left-to-right and/or right-to-left with respect to  FIGS.  1 A- 1 B ), vibratory, oscillating, or some combination thereof. In some cases, the haptic output provided by the reluctance haptic engine  101  offsets an input received at the input structure  106 . For example, in response to an inward force applied to the input structure  106  (e.g., downward with respect to  FIG.  1 B ), the reluctance haptic engine  101  may produce a haptic output that moves the input structure  106  upward to provide an opposing force, thereby offsetting the inward force applied to the input structure  106 . 
     In some cases, the reluctance haptic engine  101  may provide a global haptic output by moving a mass or weighted member within the housing  102 . The reluctance haptic engine  101  may cause the mass or weighted member to move and, in some cases, oscillate, to produce a perceptible vibration or tactile effect along an external surface of the electronic device  100 . 
     The attractor plate  112  may be or include a permanent magnet (e.g., formed of or including a magnetic material), an electromagnet, or may be or include a ferromagnetic element (e.g., formed of or including ferromagnetic material) that does not produce a magnetic field absent the influence of another magnetic field. Example magnetic materials include, but are not limited to, magnetized iron, nickel, and/or cobalt alloys (e.g., steel), ferrite, or other suitable materials. Example ferromagnetic materials include, but are not limited to, unmagnetized iron, nickel, and/or cobalt alloys (e.g., steel), ferrite, or other suitable materials. In some cases, the attractor plate  112  is formed of or includes an iron-cobalt alloy with equal parts iron and cobalt (e.g., FeCo50). The type of material used for the attractor plate  112  may depend on various factors, such as the particular electromagnetic interaction that the haptic output system uses to produce the haptic output. 
     The core  122  may be or include any suitable material or combination of materials, including metal, plastic, composites, ceramics, and so on. The core  122  may be or include a permanent magnet, or it may be or include a ferromagnetic element that does not produce a magnetic field absent the influence of another magnetic field. In some cases, the core  122  is formed of or includes an iron-cobalt alloy with equal parts iron and cobalt (e.g., FeCo50). In some cases, the core  122  is formed of or includes stainless steel, such as grade  430  stainless steel. The type of material used for the core  122  may depend on various factors, such as the particular electromagnetic interaction that the haptic output system uses to produce the haptic output. 
     The reluctance haptic engine  101  may produce haptic outputs in response to receiving one or more signals from the processing unit  130 . In some cases, the haptic outputs may correspond to inputs received by the electronic device  100  and/or outputs provided by the electronic device  100 . The haptic outputs may correspond to operational states, events, or other conditions at the electronic device  100 , including inputs received at the electronic device  100  (e.g., touch inputs, rotational inputs, translational inputs), outputs of the electronic device  100  (e.g., graphical outputs, audio outputs, haptic outputs), applications and processes executing on the electronic device, predetermined sequences, user interface commands (e.g., volume, zoom, or brightness controls, audio or video controls, scrolling on a list or page, and the like), and so on. 
     The reluctance haptic engine  101  may be operably coupled to the processing unit  130  via a connector and/or via one or more additional components of the electronic device  100 . In some cases, the reluctance haptic engine  101  may produce audio outputs in addition to or as an alternative to producing haptic outputs. For example, actuation of the reluctance haptic engine  101  may produce a sound. Audio outputs may be produced in response to any of the conditions, inputs, or the like discussed above with respect to haptic outputs. In some cases, audio outputs and haptic outputs are produced by the same actuation or actuations of the reluctance haptic engine  101 . 
     As noted above, the reluctance haptic engine  101  may actuate (e.g., transition from an unactuated configuration to an actuated configuration) in response to a reluctance force generated within the reluctance haptic engine  101  and/or in response to a force applied to the reluctance haptic engine  101 , such as by a user input on the input structure  106 . In some cases, the reluctance haptic engine  101  may include sensing elements that may be used to determine whether and to what degree the haptic device has been actuated, either by an input or a reluctance force. 
     Still with respect to  FIG.  1 B , the flexible support members  118   a / 118   b  may include one or more sensing elements  120   a / 120   b  that may be used to sense actuation based on measuring deflection and/or deformation of the flexible support members  118   a / 118   b . As noted above, the flexible support members  118   a / 118   b  may deflect or deform in response to actuation of the reluctance haptic engine  101 , for example by a user input and/or a reluctance force. The sensing elements  120   a / 120   b  may include one or more sensors (e.g., strain sensors) positioned along the flexible support members  118   a / 118   b  and configured to output a signal that varies based on the deflection and/or deformation of the flexible support members. Additionally or alternatively, other types of sensing elements may be used for sensing actuation. As one example, the reluctance haptic engine  101  may include one or more capacitive sensors. A first capacitive electrode may be positioned on the attractor plate  112  and a second capacitive electrode may be positioned on the core  122 , and a change in a capacitance between the two electrodes may be used to determine the relative position of the core  122  and the attractor plate  112 . Similarly, a first capacitive electrode may be positioned on a flexible support member  118   a / 118   b  and a second capacitive electrode may be positioned on the frame  110 . 
     In some cases, the signals provided by the sensing elements  120   a / 120   b  may be used to determine spatial parameters of the attractor plate  112 , the core  122 , the flexible support members  118   a / 118   b , and/or the input structure  106 . The spatial parameters may include, but are not limited to, a position, displacement, velocity, and acceleration. The spatial parameters determined from the signals provided by the sensing elements  120   a / 120   b  may be used to determine a location and/or magnitude (e.g., force measurement) of an input to the input structure  106 . For example, a location of an input may be determined by determining a difference between output signals of two or more sensing elements  120   a / 120   b . The magnitude of one or more output signals may be used to estimate a magnitude of force applied to the input structure  106 . 
     In some cases, the processing unit  130  may analyze detected changes in inductance between the attractor plate  112  and the core  122  to detect inputs. In some embodiments an isolated inductive sensing coil may be positioned on the frame  110  and may be used to detect inputs by detecting a change in an air gap between the frame  110  and the flexible support members  118   a / 118   b . Additionally or alternatively, an isolated inductive sensing coil may be positioned on or otherwise coupled to a flexible support member  118   a / 118   b , and may be used to detect inputs by detecting a change in an air gap between the flexible support member  118   a / 118   b  and the frame  110 . 
     In some cases, in response to detecting an input to the input structure  106 , the processing unit  130  causes the reluctance haptic engine  101  to produce a haptic output. For example, in response to receiving an inward (e.g., downward with respect to  FIGS.  1 A- 1 B ) press on the input structure  106 , the reluctance haptic engine  101  may produce a haptic output by generating a reluctance force that applies an opposing force (e.g., an outward force) on the input structure  106  to offset the user input. 
     In some cases, the signals provided by the sensing elements  120   a / 120   b  may be used to determine characteristics of haptic outputs provided by the reluctance haptic engine  101 . Characteristics of the haptic outputs may include a strength of the haptic output, a frequency of movement associated with the haptic output, and so on. The processing unit  130  may determine the haptic output characteristics by using the signals provided by the sensing elements  120   a / 120   b  to determine spatial parameters of the attractor plate  112 , the core  122 , the flexible support members  118   a / 118   b , and/or the input structure  106  caused by a reluctance force. The processing unit  130  may use the determined spatial parameters and/or haptic output characteristics to adjust the haptic outputs by changing signal characteristics (e.g., frequency, amplitude, or waveform) of the electrical current provided to the conduction loops  124 . 
     A first flexible support member  118   a  may be coupled to a first side of the core  122 , and a second flexible support member  118   b  may be coupled to a second side of the core  122  that is opposite the first side, as depicted in  FIG.  1 A . Positioning the flexible support members  118   a / 118   b  on opposite sides of the core  122  may provide enhanced stability for the core  122  and may allow the sensing elements  120   a / 120   b  positioned along the flexible support members  118   a / 118   b  to more effectively be used to detect the locations and/or magnitudes of inputs and/or feedback related to haptic outputs. 
     The flexible support members  118   a / 118   b  may be formed of any suitable material or combination of materials, including metal, plastic, composites, or ceramics. The flexible support members  118   a / 118   b  may be formed of a compliant or bendable material that allows the relative movement between the attractor plate  112  and the core  122 . In some cases, the flexible support members  118   a / 118   b  are formed of stainless steel, such as grade  301  stainless steel. The spacers  116   a / 116   b  may be formed of any suitable material or combination of materials, including metal, plastic, composites, or ceramics. In some cases, the spacers  116   a / 116   b  are formed of stainless steel, such as grade  301  stainless steel. The frame  110  may be formed of any suitable material or combination of materials, including metal, plastic, composites, or ceramics. In some cases, the frame  110  is formed of stainless steel, such as grade  316  stainless steel. 
     In various embodiments, the display  134  may be positioned at least partially within the housing  102 . The display  134  provides a graphical output, for example associated with an operating system, user interface, and/or applications of the electronic device  100 . In one embodiment, the display  134  includes one or more sensors and is configured as a touch-sensitive (e.g., single-touch, multi-touch) and/or force-sensitive display to receive inputs from a user. The display  134  is operably coupled to the processing unit  130  of the electronic device  100 , for example by a connector. In some cases, the graphical output of the display  134  is visible along at least a portion of an external surface of the electronic device  100 . 
     In various embodiments, a graphical output of the display  134  is responsive to inputs provided at the display and one or more additional input devices  128 . For example, the processing unit  130  may be configured to modify the graphical output of the display  134  in response to determining an electrocardiogram, receiving rotational inputs, receiving translational inputs, or receiving touch inputs. In some cases, a haptic output provided by the reluctance haptic engine  101  corresponds to the graphical output of the display  134 . In some cases, the reluctance haptic engine  101  may produce a haptic output that is coordinated with a change in the graphical output of the display  134 . For example, the haptic output may be produced at or near the same time as the change in the graphical output of the display  134 . In some cases, a time that the haptic output is produced overlaps a time that the graphical output of the display  134  changes. 
     The display  134  can be implemented with any suitable technology, including, but not limited to, liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. In some cases, the display  134  is positioned beneath and viewable through a transparent cover. 
     Broadly, the input devices  128  may detect various types of input, and the output devices  132  may provide various types of output. The input structure  106 , either alone or in combination with the reluctance haptic engine  101 , may be an example of an input device  128 . Similarly, the input structure  106 , either alone or in combination with the reluctance haptic engine  101 , may be an example of an output device  132 . The processing unit  130  may be operably coupled to the input devices  128  and the output devices  132 , for example by connectors. The processing unit  130  may receive input signals from the input devices  128 , in response to inputs detected by the input devices  128 . The processing unit  130  may interpret input signals received from one or more of the input devices  128  and transmit output signals to one or more of the output devices  132 . The output signals may cause the output devices  132  to provide one or more outputs. Detected input at one or more of the input devices  128  may be used to control one or more functions of the electronic device  100 . In some cases, one or more of the output devices  132  may be configured to provide outputs that are dependent on, or manipulated in response to, the input detected by one or more of the input devices  128 . The outputs provided by one or more of the output devices  132  may also be responsive to, or initiated by, a program or application executed by the processing unit  130  and/or an associated companion device. In some cases, the output devices  132  may include a speaker, and the processing unit  130  may cause the speaker to produce an audio output in conjunction with a haptic output provided using the reluctance haptic engine  101 . Examples of suitable processing units, input devices, output devices, and displays are discussed in more detail below with respect to  FIG.  7   . 
     In some implementations, the haptic engine  101  may act as a speaker for generating audio. A frequency of the core’s  122  position relative to the attractor plate  112  may be set to a relatively high frequency (e.g., above 500 Hz) or to any frequency suitable to produce audible sound. In some cases, a haptic output signal generated by the haptic engine  101  and an audio signal generated by the haptic engine  101  may be played simultaneously and/or at different frequencies. The frequencies may be multiplexed in the frequency domain and/or the time domain. 
       FIGS.  2 A- 2 C  illustrate an example electronic device  200  and an associated reluctance haptic engine  201 . The electronic device  200  illustrated in  FIG.  2 A  is a portable electronic device such as a smartphone, tablet, portable media player, or other mobile device. The electronic device  200  includes a housing  202  at least partially surrounding a display  234 , and one or more input structures  206   a  and  206   b  defining input surfaces  208   a  and  208   b , respectively. The input structures  206   a  and  206   b  of the electronic device  200  may be similar to the input structures discussed herein and may include similar structure and/or functionality. The electronic device  200  can also include one or more internal components typical of a computing or electronic device, such as, for example, one or more processing units, memory components, or network interfaces. A transparent cover  244  may be positioned over the display  234 . The transparent cover  244  may be formed from any transparent material and may be, for example, a glass, sapphire, or plastic. 
     The input structures  206   a  and  206   b  may be configured to control various functions and components of the electronic device  200 , such as a graphical output of the display  234 , an audio output, or powering the electronic device on and off. An input structure  206   a / 206   b  may be configured, for example, as a power button, a control button (e.g., volume control), or a home button. In some implementations, the input structure  206   a / 206   b  may be a portion of the display  234 . 
     The housing  202  provides a device structure, defines an internal volume of the electronic device  200 , and houses device components. In various embodiments, the housing  202  may be constructed from any suitable material, including metals (e.g., aluminum, titanium, and the like), polymers, or ceramics (e.g., glass, sapphire). In one embodiment, the housing  202  is constructed from multiple materials. The housing  202  can form an external surface or partial external surface and protective case for the internal components of the electronic device  200 , and may at least partially surround the display  234 . The housing  202  can be formed of one or more components operably connected together, such as a front piece and a back piece. Alternatively, the housing  202  can be formed of a single piece operably connected to the display  234 . 
     The display  234  can be implemented with any suitable technology, including, but not limited to, liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. The display  234  provides a graphical output, for example associated with an operating system, user interface, and/or applications of the electronic device  200 . In one embodiment, the display  234  includes one or more sensors and is configured as a touch-sensitive (e.g., single-touch, multi-touch) and/or force-sensitive display to receive inputs from a user. In various embodiments, a graphical output of the display  234  is responsive to inputs provided to the input structures  206   a  and  206   b . 
       FIGS.  2 B and  2 C  illustrate partial cross-section views of the electronic device  200  showing the input structure  206   a  and a reluctance haptic engine  201  positioned beneath the input structure, taken through section line A-A of  FIG.  2 A . The input structure  206   a  may be positioned in a recess  204  in the housing  202 . The input structure  206   a  may include or be coupled to one or more support structures  252   a / 252   b  extending through openings  254   a / 254   b  into an interior volume  256  of the electronic device  200 . The input structure  206   a  may be attached or otherwise coupled to a reluctance haptic engine  201  configured to provide haptic outputs and/or detect inputs at the input surface  208   a  of the input structure  206   a . As shown in  FIG.  2 B , each of the support structures  252   a / 252   b  may be attached or otherwise coupled to a flexible support member  218   a / 218   b . The reluctance haptic engine  201  may include an attractor plate  212 , a core  222 , conduction loops  224 , and the flexible support members  218   a / 218   b . 
     A first end of each flexible support member  218   a / 218   b  may be attached or otherwise coupled to the housing  202  (e.g., by a respective spacer  216   a / 216   b ), a frame  262 , or another component of the electronic device  200 . A second end of each flexible support member  218   a / 218   b  may be attached or otherwise coupled to an attractor plate  212  such that the attractor plate  212  is able to move relative to the housing  202 , the frame  262 , and/or the core  222 . A first end portion of a first flexible support member  218   a  may be fixed with respect to (e.g., coupled or attached to) a first side of the attractor plate  212 , and a first end portion of a second flexible support member  218   b  may be fixed with respect to (e.g., coupled or attached to) a second side of the attractor plate  212  that is opposite the first side, as shown in  FIG.  2 B . Second end portions of the first and second flexible support members  218   a / 218   b  may be fixed with respect to (e.g., coupled or attached to) the housing  202 . The input structure  206   a  may be coupled or attached to an end portion of each flexible support member  218   a / 218   b  for example by the support structures  252   a / 252   b , though the input structure  206   a  may be coupled or attached to any portion of each flexible support member  218   a / 218   b . 
     Positioning the flexible support members  218   a / 218   b  on opposite sides of the attractor plate  212  may provide enhanced stability for the attractor plate  212  and/or the input structure  206   a , and may allow sensing elements positioned along the flexible support members to more effectively be used to detect the locations and/or magnitudes of inputs and/or feedback related to haptic outputs. 
     The attractor plate  212  may be moveable with respect to the housing  202 . The core  222  may be fixed with respect to the housing  202 . In some cases, the housing  202  may be coupled or otherwise attached to the frame  262  and/or another component that is fixed with respect to the housing  202 . 
       FIG.  2 B  additionally illustrates a first gap  258  between the core  222  and the attractor plate  212  and a second gap  260  between the frame  262  and the attractor plate  212 . The first gap  258  may be reduced (e.g., made smaller) in response to an attraction force between the attractor plate  212  and the core  222  (e.g., as the attractor plate  212  moves toward the core  222 ). A reduction of the first gap  258  may correspond to the input structure  206   a  being raised with respect to the surrounding housing  202 . 
     The second gap  260  may be reduced (e.g., made smaller) in response to a user input (e.g., input force) applied to the input structure  206   a . The user input may depress the input structure  206   a , with respect to the housing  202 , and may move the attractor plate  212  closer to the frame  262 . 
     Notably, the first gap  258  and the second gap  260  are arranged such that forces imparted on the input structure  206   a  in perpendicular directions affect the gaps in opposite manners. For example, a downward force imparted on the input structure  206   a  would decrease the second gap  260  but would increase the first gap  258 . Similarly, an upward force imparted on the input structure  206   a  would increase the second gap  260  but would decrease the first gap  258 . 
     One or more connectors  250   a /250b/ 250   c  may additionally be provided to receive and/or provide electrical signals to a number of components, such as the core  222  and sensors within the flexible support members  218   a / 218   b . 
       FIG.  2 B  illustrates the reluctance haptic engine  201  in an unactuated configuration in which the attractor plate  212  and the core  222  are spaced apart by a first gap  258 . The flexible support members  218   a / 218   b  and/or the spacers  216   a / 216   b  may maintain the first gap  258  between the attractor plate  212  and the core  222 . 
       FIG.  2 C  illustrates the reluctance haptic engine  201  in an actuated configuration in which the first gap  258  between the attractor plate  212  and the core  222  is reduced or eliminated. In addition, the second gap  260  is made larger as the attractor plate  212  moves away from the frame  262 . The reluctance haptic engine  201  may actuate (e.g., transition from an unactuated configuration to an actuated configuration) in response to a reluctance force generated within the reluctance haptic engine and/or in response to a force applied to the reluctance haptic engine, such as by a user input on the input structure  206   a . As shown in  FIGS.  2 B- 2 C , the core  222  may be fixed with respect to a frame  262  and/or the housing  202 , and the attractor plate  212  may move toward the core  222  as the reluctance haptic engine  201  actuates. In some cases, the attractor plate  212  contacts the core  222  in an actuated configuration. In some cases, the attractor plate  212  does not contact the core  222  in an actuated configuration. Actuation of the reluctance haptic engine  201  may produce a haptic output or a portion thereof. The haptic output may be a localized haptic output along at least a portion of the input surface  208   a  of the input structure  206   a  and/or a global haptic output along a larger portion or a substantial entirety of the housing  202 . 
     As noted above, the flexible support members  218   a / 218   b  may deform as the reluctance haptic engine  201  actuates (e.g., as the attractor plate  212  moves toward the core  222 ). When the reluctance force is reduced or ceased (e.g., when the electrical currents applied to the conduction loops  224  are reduced or ceased) or when the input force is reduced or ceased, the biasing force of the flexible support members  218   a / 218   b  may overcome the reluctance force and/or the input force and cause the biasing members to transition from a deformed state to the non-deformed state (or from a deformed state to a less-deformed state), thereby displacing the core  222  away from the attractor plate  212  and/or reestablishing the first gap  258 . Displacing the attractor plate  212  away from the core  222  may produce a haptic output or a portion thereof, similar to actuation of the reluctance haptic engine  101  discussed above. 
     Similar to the reluctance haptic engine  101 , the flexible support members  218   a / 218   b  may include one or more sensing elements that may be used to sense actuation based on measuring deflection and/or deformation of the flexible support members. As noted above, the flexible support members  218   a / 218   b  may deflect or deform in response to actuation of the reluctance haptic engine  201 , for example by a user input and/or a reluctance force. The sensing elements may include one or more sensors (e.g., strain sensors) positioned along the flexible support members  218   a / 218   b  and configured to output a signal that varies based on the deflection and/or deformation of the flexible support members. 
     The core  222  and/or the conduction loop  224  may be communicably coupled to a processing unit or other circuitry of the electronic device  200  via a connector  250   b . In some cases, the connector  250   b  may be or include one or more traces in a flex or other cable. In some cases, multiple connectors may be incorporated into a single flex or cable. 
     The flexible support members  218   a / 218   b  may be communicably coupled to a processing unit or other circuitry of the electronic device  200  via connectors  250   a / 250   c . In some cases, the connectors  250   a / 250   c  may be or include one or more traces in a flex or other cable. In some cases, multiple connectors may be incorporated into a single flex or cable. 
     Even though in  FIGS.  2 B- 2 C  the attractor plate  212  is shown as moveable with respect to the frame  262  and/or the housing  202  and the core  222  is shown as fixed relative to the frame  262  and/or the housing  202 , in various embodiments within the scope of this disclosure, the core  222  may be moveable relative to the frame  262  and/or the housing  202  and the attractor plate  212  may be fixed relative to the frame  262  and/or the housing  202  (e.g., as depicted in  FIGS.  3 A- 3 B ). 
     The reluctance haptic engine  201  of  FIGS.  2 B- 2 C  may translate the input structure  206   a  along a path that is opposite from the input surface  208   a  (e.g., up and down with respect to  FIGS.  2 B- 2 C ). In various embodiments, reluctance haptic engines may be configured to move input structures in different directions or in multiple directions. As depicted in  FIGS.  2 B- 2 C , an input applied to the input structure  206   a  may be opposite to a reluctance force imparted to the input structure  206   a  by the reluctance haptic engine  201 . 
     Though the reluctance haptic engine  201  is discussed with respect to the input structure  206   a , in alternate or additional embodiments the input structure  206   b  may be provided with a reluctance haptic engine. 
       FIGS.  3 A- 3 B  illustrate partial cross-section views of a reluctance haptic engine  301 . The embodiment illustrated in  FIGS.  3 A- 3 B  may have substantially similar components as discussed with respect to the reluctance haptic engine  201  as described with respect to  FIGS.  2 A- 2 C  and duplicative description is omitted for clarity.  FIG.  3 A  illustrates an unactuated state and  FIG.  3 B  illustrates an actuated state where a coil  322  moves closer to an attractor plate  312 . 
     The reluctance haptic engine  301  is substantially similar to the reluctance haptic engine  201 . However, instead of a moveable attractor plate (e.g., attractor plate  212 ) and an immoveable core (e.g., core  222 ), the reluctance haptic engine  301  may implement a moveable core  322  and an immoveable attractor plate  312 . The core  322  may be moveable with respect to the housing  302 . The attractor plate  312  may be fixed with respect to the housing  302 . In some cases, the housing  302  may be coupled or otherwise attached to the frame  362  and/or another component that is fixed with respect to the housing  302 . 
     In an unactuated state, a first gap  358  may be provided between the core  322  and the attractor plate  312 . One or more conduction loops  324  of the core  322  may be periodically activated (e.g., in response to an electrical signal) and may cause the core  322  to move toward the attractor plate  312 , thereby reducing or eliminating the first gap  358 . As discussed with respect to  FIGS.  2 A- 2 C , the flexible support members  318   a / 318   b  may deform as the core  322  is attracted toward the attractor plate  312  and may cause an input structure  306   a  to move upwards. The activation of the one or more conduction loops  324  may be referenced as an actuated state. 
     As the core  322  moves toward the attractor plate  312 , thereby reducing/eliminating the first gap  358 , a second gap  360  between the core  322  and the frame  362  may be increased. Conversely, a force applied to the input structure  306   a  may increase the first gap  358  and may reduce/eliminate the second gap  360 . As a haptic force provided by the attraction between the core  322  and the attractor plate  312  opposes an input force applied to an input surface  308   a  of the input structure  306   a , a need to account for both the input and haptic force in an additive manner may be eliminated, reducing a bottom-out risk of the reluctance haptic engine  301 . 
       FIGS.  4 A- 4 E  illustrate an example reluctance haptic engine  401  as may be implemented with respect to an input region operable to receive touch inputs from a user. For example, the reluctance haptic engine  401  may be provided within a touch bar configured to receive user inputs along the touch bar. 
     The reluctance haptic engine  401  may include a top plate  402 , a core  422 , a coil (e.g., conduction loops)  424 , a first button element  408   a , a second button element  408   b , a first stool  464   a , a second stool  464   b , a first spacer  416   a , a second spacer  416   b , a first flexible support member  418   a , and a second flexible support member  418   b . Dimensions of the reluctance haptic engine  401  are not particularly limited and may, in some implementations, correspond to a length between 10 mm and 500 mm and a width between 3 mm and 50 mm. 
     The first button element  408   a  and the second button element  408   b  may be moveable with respect to certain elements of the reluctance haptic engine  401  (e.g., the first stool  464   a , the second stool  464   b , and the core  422 ). Operations of the reluctance haptic engine  401  are discussed with respect to  FIGS.  4 B- 4 E . Aspects of the reluctance haptic engine  401 , such as materials, may be similar to corresponding elements discussed with respect to  FIGS.  1 A- 3 B  and duplicative description is omitted for clarity. 
       FIGS.  4 B- 4 C  illustrate a cross-sectional view of the reluctance haptic engine  401  across line A-A (e.g., near a central portion of the reluctance haptic engine  401 ). As depicted in  FIG.  4 B , a core  422  may be coupled to a top plate  402  and may be configured as a central beam. The core  422  and the top plate  402  may be spaced from a bottom frame  462  by gaps  458   a . The bottom frame  462  may include a coil  424  affixed to a bottom portion thereof. As illustrated in  FIGS.  4 B- 4 C , the coil  424  is depicted as two parts. However, with reference to  FIG.  4 A , the coil  424  may have an ovaloid shape extending around an area defined by the core  422 . 
     The reluctance haptic engine  401  as depicted in  FIG.  4 B  illustrates an unactuated state where the coil  424  is not attracted toward the core  422  and/or the top plate  402 .  FIG.  4 C  illustrates the reluctance haptic engine  401  in an actuated state where the coil  424  is moved toward the core  422  and/or the top plate  402  due to magnetic forces, as discussed above. As the coil  424  moves toward the core  422  and/or top plate  402 , the gaps  458   a  may be reduced or eliminated (e.g., as gaps  458   b ). In this way, the bottom frame  462  may move upwards with respect to the core  422  and/or top plate  402 . 
       FIGS.  4 D- 4 E  illustrate a partial cross-sectional view across line B-B as depicted in  FIG.  4 A .  FIG.  4 D  generally corresponds to an unactuated state (e.g., the state depicted in  FIG.  4 B ) and  FIG.  4 E  generally corresponds to an actuated state (e.g., the state depicted in  FIG.  4 C ). 
     As depicted in  FIG.  4 D , a second button element  408   b  may be coupled to a portion of a coil  424 . A second spacer  416   b  may additionally be provided on the second button element  408   b  and the second spacer  416   b  may couple the second flexible element  418   b  to the second button element  408   b . The second flexible element  418   b  may further be coupled to the core  422  and/or the second stool  464   b . When the coil  424  moves toward the top plate  402  and/or the core  422 , the second button element  408  may move upwards (e.g., an actuated state as depicted in  FIG.  4 E ) with respect to the second stool  464   b , thereby causing the second flexible element  418   b  to deform. Through this arrangement, an upward force may be provided to a user of the second button element  408   b . 
     Though the cross section B-B is taken across the second button element  408   b , it is noted that a structure of the first button element  408   a , and associated components thereof, may be substantially similar. Additionally, the second button element  408   b  and the first button element  408   a  may be operated in tandem and/or may be operated individually (e.g., if multiple coils are provided within the reluctance haptic engine  401 . 
     In various embodiments, reluctance haptic engines may be configured to move input structures in different directions or in multiple directions. A reluctance haptic engine  500  may include multiple coils and/or actuators configured to move an input structure in multiple directions. For example, any number of the embodiments shown in  FIGS.  1 A- 4 E  may be combined to move an input surface laterally and/or in and out with respect to an enclosure. 
       FIG.  5    depicts a flowchart of an example method  500  for producing a haptic output at an electronic device using a reluctance haptic engine with flexible support members. At operation  502 , the electronic device detects an input at the electronic device. For example, the input may be an input to a button or other input structure. As another example, the input may be a rotational input at a crown detected by sensing rotational movement of the crown. As still another example, the input may be a touch input detected along a touch-sensitive display. In some cases, the processing unit may determine whether the input force exceeds a threshold level of movement (e.g., a threshold level of rotational movement, a threshold level of translation, etc.) In some cases, the method only proceeds if an input force of the input exceeds the threshold level of force. 
     At operation  504 , the processing unit determines output characteristics to be produced by the electronic device in response to the input received at operation  502 . In some cases, the output characteristics correspond to one or more characteristics of the input detected at operation  502 . For example, the associated output characteristics may correspond to a force of the input, a location of the input, a rotational speed or position of the crown, an output associated with a rotational input, a user interface command associated with the user input, and so on. The processing unit may determine one or more characteristics of the input to determine the output characteristics. 
     In some cases, determining the output characteristics at operation  504  may include determining a strength, length, or other characteristics of a haptic output to be produced. For example, the processing unit may determine whether to provide a localized haptic output or a global haptic output based, at least in part, on a characteristic of the input. 
     At operation  506 , the processing unit outputs an output signal to provide a haptic output that corresponds to the output characteristics determined at operation  504 . The output signal may be transmitted to a reluctance haptic engine of the electronic device to direct the reluctance haptic engine to produce the haptic output. 
     At operation  508 , in response to receiving the output signal from the processing unit, the electronic device applies electrical current to conduction loops of a reluctance haptic engine to cause the reluctance haptic engine to actuate (e.g., move from an unactuated configuration to an actuated configuration). In particular, the force generated at operation  508  may oppose the input received at operation  502 . In some cases, actuation of one or more reluctance haptic engines produces a first portion of the haptic output, for example by causing an input structure to move. As noted above, a gap between an attractor plate and a core of the reluctance haptic engine may be reduced or closed (e.g., the attractor plate may move toward the core and/or the core may move toward the attractor plate), thereby moving an input structure coupled to the attractor plate or the core (e.g., along a path that is parallel to an input surface of the input structure, along a path that is perpendicular to the input surface, or along a different path). 
     In some cases, following actuation of the reluctance haptic engine, the electrical current may be ceased, reduced, or otherwise changed, which causes the reluctance haptic engine to be restored (either partially or fully) to its initial configuration (e.g., to reestablish a gap between an attractor and one or more cores). As noted above, a gap between an attractor plate and a core of the reluctance haptic engine may be increased or restored (e.g., the attractor plate may move away from the core and/or the core may move away from the attractor plate), thereby moving an input structure coupled to the attractor plate or the core (e.g., along a path that is parallel to an input surface of the input structure, along a path that is perpendicular to the input surface, or along a different path). 
     In some cases, one or more reluctance haptic engines being restored produces a second portion of the haptic output, for example by causing the input structure to move. As noted above, in some cases, flexible support members of the reluctance haptic engine at least partially cause the restoration of the reluctance haptic engine, for example by applying a biasing force to move the attractor plate and/or the core(s) to an initial position. 
     In some cases, the reluctance haptic engine being restored may prepare the reluctance haptic engine for a subsequent actuation. In various embodiments, once the reluctance haptic engine has been restored (either partially or fully), it may be subsequently actuated by applying additional electrical current to the conduction loops (e.g., in response to receiving another output signal from the processing unit) to provide a third portion of the haptic output. The reluctance haptic engine may be subsequently restored (either partially or fully) to its initial configuration (either partially or fully), which may provide a fourth portion of the haptic output. Actuation and restoration may be repeated to repeatedly move the input structure in alternating directions to produce one or more haptic outputs and/or portions thereof. 
     The method  500  is an example method for providing haptic outputs and is not limiting. Methods for providing haptic outputs may omit and/or add steps to the method  500 . Similarly, steps of the method  500  may be performed in different orders than the example order discussed above. The method  500  refers to providing haptic outputs in response to an input, but this is just one example. Haptic outputs may also be provided in response to a system state, an application operation on a device, a device state (e.g., temperature), application or system alerts (e.g., calendar alerts, notifications, alarms, and the like), incoming communications, push notifications, and so on. 
       FIG.  6    illustrates an example wearable electronic device  670  that may incorporate a reluctance haptic engine with flexible support members, configured as an electronic watch. The wearable electronic watch  670  is similar to the electronic devices discussed herein, and may include similar features and/or components, including a device housing  672 , one or more input structures 678/680 defining one or more input surfaces  678   a / 680   a , one or more output devices, a display  674  positioned beneath the cover  676 , and a processing unit positioned at least partially within the housing  672 . The wearable electronic device  670  may additionally include one or more bands  682  configured to couple the wearable electronic device  670  with a body part of a user. 
     In some cases, the wearable electronic device  670  includes a crown  680  configured to receive translational inputs, rotational inputs, and/or touch inputs. Inputs received at the crown  680  may result in changes in outputs provided by the wearable electronic device  670  such as a graphical output of the display, and/or otherwise modify operations of the wearable electronic device  670 . In some cases, the crown  680  may be positioned along a side of the housing  672 , and may extend through an opening defined in the housing  672 . The crown  680  may include a user-rotatable crown body and a shaft. The crown body may be positioned at least partially outside of the device housing  672  and may be coupled to the shaft. In some cases, the shaft extends from the crown body and extends through the opening defined in the housing  672 . 
     In some cases, the wearable electronic device  670  may include a conductive portion that may be used to perform an electrocardiogram (ECG) measurement. The crown body or another input structure may define a conductive surface for receiving touch inputs. In some cases, the conductive surface functions as an electrode to sense voltages or signals indicative of one or more touch inputs and/or biological parameters, such as an electrocardiogram, of a user in contact with the conductive surface. The housing  672  may define a touch-sensitive or conductive surface that is electrically coupled to the processing unit and also functions as an electrode. The processing unit may determine an ECG using outputs of the electrodes of the crown body and the housing  672 . In various embodiments, the crown  680  is electrically isolated from the housing  672 , for example to allow separate measurements at the electrodes. In various embodiments, the crown body may be electrically coupled to the processing unit or another circuit of the wearable electronic device  670 , for example via a connector and/or the shaft. 
       FIG.  7    illustrates a sample electrical block diagram of an electronic device  700  that may incorporate a reluctance haptic engine. The electronic device may in some cases take the form of any of the electronic devices described with reference to  FIGS.  1 A- 6   , or other portable or wearable electronic devices. The electronic device  700  can include a display  708  (e.g., a light-emitting display), a processing unit  702 , a power source  712 , a memory  704  or storage device, an input device  706  (e.g., a crown, a button), and an output device  710  (e.g., a reluctance haptic engine). 
     The processing unit  702  can control some or all of the operations of the electronic device  700 . The processing unit  702  can communicate, either directly or indirectly, with some or all of the components of the electronic device  700 . For example, a system bus or other communication mechanism  714  can provide communication between the processing unit  702 , the power source  712 , the memory  704 , the input device(s)  706 , and the output device(s)  710 . 
     The processing unit  702  can be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processing unit  702  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 “processing unit” 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  700  can be controlled by multiple processing units. For example, select components of the electronic device  700  (e.g., an input device  706 ) may be controlled by a first processing unit and other components of the electronic device  700  (e.g., the display  708 ) may be controlled by a second processing unit, where the first and second processing units may or may not be in communication with each other. In some cases, the processing unit  702  may determine a biological parameter of a user of the electronic device, such as an ECG for the user. 
     The power source  712  can be implemented with any device capable of providing energy to the electronic device  700 . For example, the power source  712  may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power source  712  can be a power connector or power cord that connects the electronic device  700  to another power source, such as a wall outlet. 
     The memory  704  can store electronic data that can be used by the electronic device  700 . For example, the memory  704  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  704  can be configured as any type of memory. By way of example only, the memory  704  can be implemented as random access memory, read-only memory, Flash memory, removable memory, other types of storage elements, or combinations of such devices. 
     In various embodiments, the display  708  provides a graphical output, for example associated with an operating system, user interface, and/or applications of the electronic device  700 . In one embodiment, the display  708  includes one or more sensors and is configured as a touch-sensitive (e.g., single-touch, multi-touch) and/or force-sensitive display to receive inputs from a user. For example, the display  708  may be integrated with a touch sensor (e.g., a capacitive touch sensor) and/or a force sensor to provide a touch- and/or force-sensitive display. The display  708  is operably coupled to the processing unit  702  of the electronic device  700 . 
     The display  708  can be implemented with any suitable technology, including, but not limited to liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. In some cases, the display  708  is positioned beneath and viewable through a cover that forms at least a portion of an enclosure of the electronic device  700 . 
     In various embodiments, the input devices  706  may include any suitable components for detecting inputs. Examples of input devices  706  include audio sensors (e.g., microphones), optical or visual sensors (e.g., cameras, visible light sensors, or invisible light sensors), proximity sensors, touch sensors, force sensors, mechanical devices (e.g., crowns, switches, buttons, or keys), vibration sensors, orientation sensors, motion sensors (e.g., accelerometers or velocity sensors), location sensors (e.g., global positioning system (GPS) devices), thermal sensors, communication devices (e.g., wired or wireless communication devices), resistive sensors, magnetic sensors, electroactive polymers (EAPs), strain gauges, electrodes, and so on, or some combination thereof. Each input device  706  may be configured to detect one or more particular types of input and provide a signal (e.g., an input signal) corresponding to the detected input. The signal may be provided, for example, to the processing unit  702 . 
     As discussed above, in some cases, the input device(s)  706  include a touch sensor (e.g., a capacitive touch sensor) integrated with the display  708  to provide a touch-sensitive display. Similarly, in some cases, the input device(s)  706  include a force sensor (e.g., a capacitive force sensor) integrated with the display  708  to provide a force-sensitive display. 
     The output devices  710  may include any suitable components for providing outputs. Examples of output devices  710  include audio output devices (e.g., speakers), visual output devices (e.g., lights or displays), tactile output devices (e.g., haptic output devices), communication devices (e.g., wired or wireless communication devices), and so on, or some combination thereof. Each output device  710  may be configured to receive one or more signals (e.g., an output signal provided by the processing unit  702 ) and provide an output corresponding to the signal. 
     In some cases, input devices  706  and output devices  710  are implemented together as a single device. For example, an input/output 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, infrared, and Ethernet connections. 
     The processing unit  702  may be operably coupled to the input devices  706  and the output devices  710 . The processing unit  702  may be adapted to exchange signals with the input devices  706  and the output devices  710 . For example, the processing unit  702  may receive an input signal from an input device  706  that corresponds to an input detected by the input device  706 . The processing unit  702  may interpret the received input signal to determine whether to provide and/or change one or more outputs in response to the input signal. The processing unit  702  may then send an output signal to one or more of the output devices  710 , to provide and/or change outputs as appropriate. 
     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: 20220630
Publication Date: 20231107
Grant Date: 20231107
Priority Date: 20210921
Inventors: CHEN, DENIS G.
KOCH, TIMOTHY D.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/03547", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/0339", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/016", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/0339", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0362", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/0339", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 85706306