Surface acoustic devices with haptic or acoustic feedback

Abstract

Various exemplary embodiments relate to providing audio or tactile feedback to a user. The device may include a detection circuit connected to a first coil, the detection circuit configured to detect a user input at the surface based on a trigger signal including a voltage or current induced in the first coil by a displacement of the surface by the user. The device may further include a feedback circuit connected to a second coil, the feedback circuit configured to activate a feedback signal in response to detection of the user input by the detection circuit, the second coil configured to cause or change a movement of the surface based on a magnetic field configured to be generated by the second coil upon activation of the feedback signal. Apparatus, methods, and computer programs are disclosed.

Description

[Technical field]

[0001] Various exemplary embodiments relate generally to the field of providing acoustic or haptic feedback to a user. Some exemplary embodiments relate to a transducer, such as a speaker, configured to convert electrical energy into vibrations and further configured to operate as a user input device. [Background technology]

[0002] A transducer can convert energy from one form to another and can be applied to various types of devices, such as a speaker, to generate sound based on an electrical signal. Generally, a speaker can comprise a surface that vibrates according to an electrical signal to generate sound. In a surface audio device, for example, a surface such as a mobile phone display, a television screen, or a panel in a car interior can be configured as a surface for generating sound. The sound can be used to provide an acoustic feedback to a user. Furthermore, the vibration can be used to provide a tactile or tactile feedback to a user. Summary of the Invention

[0003] This Summary is provided to introduce in a simplified form some of the concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The scope of protection sought for various embodiments of the present disclosure is defined by the independent claims.

[0004] Exemplary embodiments of the present disclosure make it possible to improve the user experience by using a surface acoustic device to receive user input and providing acoustic or haptic feedback to the user input. These and other advantages can be achieved by means of the features of the independent claims. Further advantageous embodiments are set out in the dependent claims, the description and the drawings.

[0005] According to a first aspect, the device may include a detection circuit connected to the first coil, the detection circuit configured to detect user input at the surface based on a trigger signal including a voltage or current induced in the first coil by a displacement of the surface by a user, and a feedback circuit connected to the second coil, the feedback circuit configured to activate the feedback signal in response to detection of the user input by the detection circuit, the second coil configured to cause or vary movement of the surface based on a magnetic field configured to be generated by the second coil upon activation of the feedback signal.

[0006] According to an exemplary embodiment of the first aspect, the apparatus may further comprise at least one magnetic element, wherein the displacement of the surface is configured to cause relative movement between the at least one magnetic element and the first coil to induce a voltage or a current in the first coil.

[0007] According to an exemplary embodiment of the first aspect, the device may further comprise a top portion comprising the first magnetic element and a base portion comprising the first coil and the second coil, and a displacement of the surface by a user may be configured to move the top portion towards the base portion.

[0008] According to an exemplary embodiment of the first aspect, the first coil and the second coil may be substantially concentric and have substantially the same diameter. The first coil may be disposed closer to the upper portion than the second coil.

[0009] According to an exemplary embodiment of the first aspect, the base portion may further comprise at least one second magnetic element, and at least a portion of the first coil and / or at least a portion of the second coil may be configured to surround the at least one second magnetic element.

[0010] According to an exemplary embodiment of the first aspect, the resistance of the first coil may be between 22 and 26 ohms. The length of the wire of the first coil may be between 3.8 and 4.2 m.

[0011] According to an exemplary embodiment of the first aspect, at least a portion of the at least one second magnetic element may be configured to surround the first coil. At least a portion of the second coil may be configured to surround the at least one second magnetic element.

[0012] According to an exemplary embodiment of the first aspect, the resistance of the first coil may be between 29 and 33 ohms. The length of the wire of the first coil may be between 4.8 and 5.2 m.

[0013] According to an exemplary embodiment of the first aspect, at least one of the first magnetic element and the second magnetic element may comprise a permanent magnet.

[0014] According to an exemplary embodiment of the first aspect, the first magnetic element or the second magnetic element may comprise a magnetizable element.

[0015] According to an exemplary embodiment of the first aspect, the feedback signal may comprise a DC voltage or a DC current.

[0016] According to an exemplary embodiment of the first aspect, the apparatus may further comprise a low pass filter configured to filter the trigger signal, The low pass filter may be configured to pass haptic frequencies and suppress acoustic frequencies.

[0017] According to an exemplary embodiment of the first aspect, the cut-off frequency of the low pass filter may be between 8 and 12 Hz.

[0018] According to an exemplary embodiment of the first aspect, the detection circuitry may be further configured to provide a first indication of the user input in response to detecting a peak in the trigger signal, and to provide a second indication of the user input in response to detecting a zero crossing of the trigger signal after the peak in the trigger signal.

[0019] According to an exemplary embodiment of the first aspect, the detection circuitry may be further configured to differentiate the trigger signal to obtain a derivative of the trigger signal, and in response to detecting that the trigger signal is greater than zero and the derivative of the trigger signal is substantially equal to zero, provide a first indication of the user input.

[0020] According to an exemplary embodiment of the first aspect, the detection circuitry may be further configured to integrate the trigger signal and, in response to detecting that the integrated trigger signal reaches or exceeds a first threshold and the trigger signal is greater than zero, provide a third notification of the user input.

[0021] According to an exemplary embodiment of the first aspect, the detection circuit may be further configured to trigger the feedback circuit to activate the feedback signal in response to at least one of the first indication of the user input, the second indication of the user input, or the third indication of the user input.

[0022] According to an exemplary embodiment of the first aspect, the detection circuit may be further configured to calibrate a zero level of the trigger signal based on an idle voltage of the first coil.

[0023] According to an exemplary embodiment of the first aspect, the detection circuitry may be further configured to activate detection of the user input in response to detecting the trigger signal reaching or exceeding a second threshold.

[0024] According to an exemplary embodiment of the first aspect, the detection circuit may be coupled to the plurality of first coils. The detection circuit may be further configured to detect a user input at the surface based on a plurality of trigger signals corresponding to the plurality of first coils. The feedback circuit may be further configured to activate a plurality of feedback signals for the plurality of first coils in response to detection of the user input by the detection circuit.

[0025] According to an exemplary embodiment of the first aspect, the detection circuitry may be further configured to detect a position of the user input on the surface based on a voltage or current level induced by the user input in the plurality of first coils.

[0026] According to an exemplary embodiment of the first aspect, the feedback circuit may be further configured to determine a plurality of feedback signals based on a position of the user input on the surface.

[0027] According to an exemplary embodiment of the first aspect, the feedback circuitry may be further configured to determine a plurality of feedback signals based on a mapping between a position of the user input on the surface and the at least one feedback signal.

[0028] According to an exemplary embodiment of the first aspect, the feedback circuitry may be further configured to receive notification of a mapping between a position of a user input on the surface and the at least one feedback signal.

[0029] According to an exemplary embodiment of the first aspect, the multiple feedback signals may be identical.

[0030] According to a second aspect, the method may include detecting a user input at the surface based on a trigger signal including a voltage or current induced in a first coil by a displacement of the surface by a user, activating a feedback signal in response to the detection of the user input, and generating a magnetic field by a second coil in response to the activation of the feedback signal to cause or alter movement of the surface.

[0031] According to an exemplary embodiment of the second aspect, the feedback signal may comprise a DC voltage or a DC current.

[0032] According to an exemplary embodiment of the second aspect, the method may further include filtering the trigger signal with a low pass filter configured to pass haptic frequencies and suppress acoustic frequencies.

[0033] According to an exemplary embodiment of the second aspect, the cut-off frequency of the low pass filter may be between 8 and 12 Hz.

[0034] According to an example embodiment of the second aspect, the method may further include providing a first notification of the user input in response to detecting a peak in the trigger signal, and / or providing a second notification of the user input in response to detecting a zero crossing of the trigger signal after the peak in the trigger signal.

[0035] According to an example embodiment of the second aspect, the method may further include differentiating the trigger signal to obtain a derivative of the trigger signal, and in response to detecting that the trigger signal is greater than zero and the derivative of the trigger signal is substantially equal to zero, providing a first indication of the user input.

[0036] According to an exemplary embodiment of the second aspect, the method may further include integrating the trigger signal and, in response to detecting that the integrated trigger signal reaches or exceeds a first threshold and the trigger signal is greater than zero, providing a third notification of the user input.

[0037] According to an exemplary embodiment of the second aspect, the method may further include triggering a feedback circuit to activate the feedback signal in response to at least one of the first notification of the user input, the second notification of the user input, or the third notification of the user input.

[0038] According to an exemplary embodiment of the second aspect, the method may further include calibrating a zero level of the trigger signal based on an idle voltage of the first coil.

[0039] According to an exemplary embodiment of the second aspect, the method may further include activating detection of a user input in response to detecting the trigger signal reaching or exceeding a second threshold.

[0040] According to an exemplary embodiment of the first aspect, the detection circuit may be coupled to the plurality of first coils. The method may further include detecting a user input at the surface based on a plurality of trigger signals corresponding to the plurality of first coils, and activating a plurality of feedback signals for the plurality of first coils in response to detecting the user input by the detection circuit.

[0041] According to an exemplary embodiment of the second aspect, the method may further include detecting a position of the user input on the surface based on a voltage or current level induced by the user input in the plurality of first coils.

[0042] According to an exemplary embodiment of the second aspect, the method may further include determining a plurality of feedback signals based on a position of the user input on the surface.

[0043] According to an exemplary embodiment of the second aspect, the method may further include determining a plurality of feedback signals based on a mapping between a position of the user input on the surface and the at least one feedback signal.

[0044] According to an exemplary embodiment of the second aspect, the method may further include receiving notification of a mapping between a position of the user input on the surface and the at least one feedback signal.

[0045] According to an exemplary embodiment of the second aspect, the multiple feedback signals may be identical.

[0046] According to a third aspect, the computer program may include instructions for causing the apparatus to at least: detect a user input at the surface based on a trigger signal comprising a voltage or current induced in the first coil by a displacement of the surface by the user, activate a feedback signal in response to the detection of the user input, and generate a magnetic field by the second coil to cause or alter a movement of the surface in response to the activation of the feedback signal. The computer program may further include instructions for causing the apparatus to perform any exemplary embodiment of the method of the second aspect.

[0047] According to a fourth aspect, the apparatus may include means for detecting a user input at the surface based on a trigger signal comprising a voltage or current induced in the first coil by a displacement of the surface by the user, means for activating a feedback signal in response to the detection of the user input, and means for generating a magnetic field by the second coil to cause or alter movement of the surface in response to the activation of the feedback signal. The apparatus may further comprise means for performing any exemplary embodiment of the method of the second aspect.

[0048] Any exemplary embodiment may be combined with one or more other exemplary embodiments. Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings. [Brief description of the drawings]

[0049] The accompanying drawings are included to provide a further understanding of the exemplary embodiments, constitute a part of this specification, explain the exemplary embodiments, and together with the description facilitate an understanding of the exemplary embodiments. [Figure 1] FIG. 1 illustrates a cross-sectional view of an example of a surface acoustic device configured to provide acoustic or haptic feedback, according to one or more exemplary embodiments. [Diagram 2] FIG. 2 illustrates an example block diagram of a surface acoustic device with acoustic or haptic feedback, according to one or more exemplary embodiments. [Diagram 3] FIG. 3 is a diagram illustrating an example of a surface acoustic device having a detection coil and a feedback coil disposed outside a magnetic element, according to one or more exemplary embodiments. [Figure 4] FIG. 4 is a diagram illustrating an example of a surface acoustic device having a detection coil disposed inside a circular magnetic element, according to one or more exemplary embodiments. [Diagram 5]FIG. 5 illustrates an example of a surface acoustic device having a detection coil disposed on top of a magnetic element, according to one or more exemplary embodiments. [Figure 6] FIG. 6 illustrates an example of a block diagram of a surface acoustic device with a low pass filter of the trigger signal, according to one or more exemplary embodiments. [Figure 7] FIG. 7 is a diagram illustrating an example of a raw trigger signal for a press and release action, according to one or more exemplary embodiments. [Figure 8] FIG. 8 illustrates an example of a low-pass filtered trigger signal for a press and release action, in accordance with one or more exemplary embodiments. [Figure 9] FIG. 9 illustrates example force curves for a press and release operation, according to one or more exemplary embodiments. [Figure 10] FIG. 10 illustrates an example functional block diagram of a user input detection circuit, according to one or more exemplary embodiments. [Figure 11] FIG. 11 illustrates an example block diagram of a detection circuit having thresholds to enable zero-level calibration and user input detection in accordance with one or more exemplary embodiments. [Figure 12] FIG. 12 is a diagram illustrating an example of an apparatus including multiple surface acoustic devices, according to one or more exemplary embodiments. [Figure 13] FIG. 13 illustrates an example of an apparatus configured to implement one or more exemplary embodiments. [Figure 14] FIG. 14 illustrates an example of a method for providing haptic or audio feedback to a user, according to one or more exemplary embodiments.

[0050] Like references are used to designate like parts in the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Reference will now be made in detail to exemplary embodiments that are illustrated in the accompanying drawings. The detailed description provided below in conjunction with the accompanying drawings is intended as an explanation of the embodiments, and is not intended to represent the only manner in which the embodiments may be constructed or utilized. The description sets forth the functions of the embodiments, and the sequence of steps for constructing and operating the embodiments. However, the same or equivalent functions and sequences may be accomplished by different embodiments.

[0052] FIG. 1 illustrates a cross-sectional view of an example of a surface acoustic device configured to provide acoustic or haptic feedback, according to an exemplary embodiment. In general, the surface acoustic device 100 can be configured to generate vibrations, such as, for example, an acoustic output (e.g., an acoustic signal and / or acoustic feedback) or a haptic output (e.g., haptic feedback) to a user, for example, in response to detecting a user input (e.g., a press) of the surface acoustic device 100. When configured to provide haptic feedback, the surface acoustic device 100 may also be referred to as a surface acoustic device or a surface audio haptic device (SAHD). The surface acoustic device 100 may comprise or be configured to be coupled to a surface 102, for example, which may be configured to be mechanically displaced along an axis 130. The axis 130 may be substantially perpendicular to the surface 102. The surface acoustic device 100 may further comprise a first magnetic element 110, which may be coupled to or configured to be coupled to the surface 102. The surface acoustic device 100 may further comprise at least one support member 108 for supporting the surface 102 relative to the base 104, for example. The surface acoustic device 100 may further comprise a first coil 112 that may be coupled or configured to be coupled to the surface 102. For example, the first coil 112 may be attached to the first magnetic element 110 and disposed below the first magnetic element 110 along the axis 130. Thus, the first magnetic element 110 may be disposed at least partially (partially or completely) between the first coil 112 and the surface 102. The surface acoustic device 100 may further comprise a second magnetic element 120 coupled to the base 104. The second magnetic element 120 may be disposed facing the first magnetic element 110, as shown in FIG. 1. The surface acoustic device 100 may further comprise a second coil 122 disposed between the first and second magnetic elements 110, 120. The second coil 122 may be attached to the second magnetic element 120 and disposed above the second magnetic element 120 along the axis 130 .Thus, the second magnetic element 120 may be disposed at least partially between the second coil 122 and the base 104. The first coil 112 may be referred to as a sensing coil or detection coil. The second coil 122 may be referred to as a feedback coil, a tactile coil, an acoustic coil, a sound coil, or a voice coil. The first magnetic element 110 and / or the second magnetic element 120 may include a permanent magnet or a magnetizable material, for example, a ferromagnetic material such as iron and / or a ferrimagnetic material. The magnetic elements may take different forms in different embodiments, and at least one of the magnetic elements 110, 120 may include a permanent magnet. The magnetic element 110 and / or the magnetic element 120 may also be implemented as a combination of multiple magnetic members.

[0053] According to an exemplary embodiment, the first magnetic element 110 may comprise a permanent magnet. Thus, the first magnetic element 110 may generate a static magnetic field within the surface acoustic device 100. The second magnetic element 120 may include a magnetizable material that may be magnetized by the magnetic field provided by the first magnetic element 110. However, the second magnetic element 120 may be absent or may comprise a permanent magnet.

[0054] According to an example embodiment, the second magnetic element 120 may comprise a permanent magnet. The first magnetic element may comprise a magnetizable material. An attractive force may be generated between the first magnetic element 110 and the second magnetic element 120. The first magnetic element 110 may alternatively comprise another permanent magnet.

[0055] The magnetic field provided by at least one of the magnetic elements 110, 120 creates an electromagnetic force (EMF) on the surface 102 when current is applied to the second coil 122, or induces a voltage in the first coil 112 when pressing against the surface 102. The system is characterized by EMF(V)=Blv, where B is the magnetic flux density of the magnetic field, l is the length of the coil wire of the first coil 112, and v is the velocity of movement of the first coil 112 along the axis 130 caused by the pressing force applied to the surface 102. The electromotive force can be expressed in volts (V). The surface 102 and / or at least one support member 108 may comprise at least one elastic element providing a force (e.g., a repulsive force), which may act as a repulsive force against the electromagnetic force or pressing force. In this manner, the surface 102 may be supported against the base 104, which in some embodiments may comprise the support member(s) 108. This allows the surface to move relative to axis 130 with a velocity (v), inducing a voltage in first coil 112. Thus, surface 102 may be in force equilibrium. Typically, surface 102 may comprise a vibrating panel. Surface 102 may be rigid, e.g., non-flexible or only slightly flexible. Surface 102 may comprise a flat surface. Surface 102 may comprise, for example, metal, wood, glass, and / or plastic. Surface 102 may have a thickness of at least 1 mm, 2 mm, 3 mm, 5 mm, 1 cm, 2 cm, or 5 cm. Base 104 may comprise a mechanically grounded panel.

[0056] The electrical signal in the second coil 122 may be proportional to the mechanical displacement of the surface 102. The force balance may be broken by the electrical signal in the second coil 122. For example, the force balance may be broken when an electrical signal is provided to the second coil 122 via the acoustic / feedback signal terminal. Thus, the surface 102 may be vibrated according to an electromotive force (EMF) generated by an electrical input signal in the second coil 122. Alternatively, the force balance may be broken by mechanically displacing the surface 102 from the force balance position, for example, by a user pressing the surface 102. It is noted that the polarity of the magnetic elements 110, 120 may be arranged in any suitable manner. For example, in an attraction configuration, the opposite magnetic poles may be arranged facing each other (NS vs. NS or SN vs. SN). Thus, force balance may be caused by an attractive magnetic force between the magnetic elements 110, 120 and an opposing support force provided by the support member(s) 118 that prevents the magnetic elements 110, 120 from being attracted to each other. Alternatively, in a repulsive configuration, like magnetic poles may be placed opposite each other (NS vs. SN, or SN vs. NS). Thus, force balance may be caused by a repulsive magnetic force between the magnetic elements 110, 120 and an opposing support force provided by the support member(s) 118 that prevents the magnetic elements 110, 120 from trying to move away from each other.

[0057] The surface acoustic device 100 can be configured to generate an acoustic output according to an electrical input signal. The acoustic output may refer to and / or include a sound detectable by the human ear, i.e., a sound that can be heard by a human. In some examples, it may refer to a sound detectable by an animal(s) and / or an acoustic sensor (such as a microphone). For example, the acoustic output may include music, speech, sound effects, and the like. It is also noted that the surface 102 and the base 104 may be or include any suitable device, such as, for example, a mobile phone, a television, a computer, a music player, or other type of user device. For example, the base 104 may form at least a portion of a frame of the device. For example, the surface 102 may be or include a screen of a device (e.g., an electronic device). The provided solution is applicable, for example, to the automotive industry (e.g., automobiles). The surface 102 may include an automotive panel, such as an automotive interior panel (e.g., a door panel, a ceiling or roof panel, a wall panel, a frame panel, or other part of the automotive interior). Surface 102 may include, for example, an automobile display. Surface 102 may alternatively be included in a wearable device, such as a wearable electronic device. For example, surface 102 may be included in a portable electronic device, such as a watch or wrist device (e.g., surface 102 may be included in a display of such a device).

[0058] As mentioned above, the surface acoustic device 100 may include one or more acoustic / feedback signal terminals electrically connected to the second coil 122. The acoustic / feedback signal terminal(s) may be used to provide an acoustic signal and / or a feedback signal to the second coil 122 to cause the surface 102 to generate acoustic and / or haptic vibrations. The feedback signal may include acoustic feedback and / or haptic feedback. The surface acoustic device 100 may further include one or more trigger signal terminals electrically connected to the first coil 112. The trigger signal may alternatively be referred to as a sensing signal or a detection signal. The trigger signal(s) terminal(s) may cause the first coil 112 to emit a trigger signal. For example, mechanical displacement of the surface 102, such as by pressing the surface 102 along the axis 130, may induce a voltage (trigger voltage) between the trigger signal terminals. The trigger signal may be used to detect pressing of the surface 102 and trigger the acoustic / haptic feedback generated by the second coil 122, as described further below. Although the acoustic / feedback signal terminals and the trigger signal terminals are illustrated as including both positive and negative terminals, it will be understood that each coil may alternatively be connected to a single terminal relative to ground potential.

[0059] The surface 102 can be supported relative to the base 104 using various solutions. The support member(s) 108 can, for example, comprise a spring(s) disposed between the surface 102 and the base 104. However, the support member(s) 108 may not be present in some embodiments, as the repulsive force can also be provided by other means, such as, for example, a pair (or pairs) of magnets connected to the surface 102 and the base 104. For example, the pair (or pairs) of magnets can be configured to provide a force opposite to the force provided by the first magnetic element 110 and the second magnetic element 120. For example, if the first magnetic element 110 and the second magnetic element 120 are configured to provide an attractive force, the pair (or pairs) of magnets can be configured to provide a repulsive force, or vice versa.

[0060] Coupling the magnetic element to the surface 102 or base 104 may include fastening or attaching the magnetic element to the surface 102 or base 104. Such fastening may be performed, for example, using an adhesive and / or a screw(s). The magnetic element may also be printed on the surface 102 and / or base 104. Thus, the coupled may include printing (e.g., electronics printing). Furthermore, disposing the coils 112, 122 between the magnetic elements 110, 120 may include coupling (e.g., fastening or attaching) the coils to the respective magnetic elements. However, the first coil 112 and / or the second coil 122 may also be disposed as separate elements between the magnetic elements 110, 120. Thus, the respective coils 112, 122 may not be in physical contact with the respective magnetic elements 110, 120. For example, the first coil 112 can be attached to the surface 102 or other portion of the surface acoustic device 100 to position the first coil 112 in the area between the magnetic elements 110, 120. Similarly, the second coil 122 can be attached to the base 104 or other portion of the surface acoustic device 100 to position the second coil 122 in the area between the magnetic elements 110, 120. It should be noted that the example of FIG. 1 illustrates one possible arrangement of the magnetic elements 110, 120 and the coils 112, 122 relative to the surface 102 and base 104. Similar functionality can be achieved by alternative arrangements, for example, as described with reference to FIGS. 3 and 4. Thus, exemplary embodiments of the present disclosure can implement user input detection and tactile and / or acoustic feedback functionality within a single structure. For example, a single coil can be used to provide both acoustic signals and feedback to the user, and other coils can be integrated within the same structure and dedicated to detecting user input.

[0061] 2 shows an example of a block diagram of a surface acoustic device with acoustic or haptic feedback, according to one or more exemplary embodiments. A simplified version of a surface acoustic device 100 is shown in FIG. The surface acoustic device 100 may include first and second coils 112, 122. In addition to these components, the surface acoustic device 200 may include a detection circuit 210 and a feedback circuit 220.

[0062] The detection circuit 210 may be (electrically) connected to the first coil 112, for example, to receive a trigger signal(s) from the first coil 112 and detect a user input based on the trigger signal. The trigger signal may include a voltage or current induced in the first coil 112 by a displacement of the surface by a user. In response to detecting a user input, for example, a press of the surface 102, the detection circuit 210 may provide an enable feedback signal (EN_FB) to the feedback circuit 220. Providing the enable signal may include changing a state of the enable signal, for example, from a level indicative of a logic low to a level indicative of a logic high.

[0063] The feedback circuit 220 may be (electrically) connected to the second coil 122, for example, to provide a feedback signal(s) to the second coil 122. The feedback circuit 220 may be configured to activate (and deactivate) the feedback signal according to an enable feedback signal provided by the detection circuit, i.e., in response to detection of a user input by the detection circuit 210. The second coil 122 may be configured to cause a movement of the surface 102 based on a magnetic field configured to be generated by the second coil 122 upon activation of the feedback signal. For example, if a direct current (DC) signal is provided as the feedback signal, the magnetic field may cause the surface 102 to lift, thereby causing a single bump as haptic feedback. Alternatively, the feedback signal may include an alternating current (AC) signal, which may cause the surface 102 to vibrate. The vibration of the surface 102 may be sensed by the user as haptic and / or acoustic feedback.

[0064] The second coil 122 may additionally be connected to an acoustic source, for example an audio amplifier (AMP) integrated with the feedback circuit 220, which may be configured to reproduce an acoustic signal (e.g., music or sound) by inducing vibration of the surface 102 by the second coil 122. When the acoustic reproduction is running and the surface 102 is vibrating, the feedback signal may change the movement of the surface 102 by changing the magnetic field provided by the second coil 122. For example, a haptic feedback signal or an acoustic feedback signal may be superimposed on the acoustic signal reproduced by the acoustic source.

[0065] The detection circuit 210 and the feedback circuit can be implemented using analog or digital circuits, or a combination thereof. In the analog domain, these circuits can be implemented based on, for example, comparison circuits, differentiation circuits, integration circuits, etc. In the digital domain, the circuits can comprise digital components, such as, for example, logic gates, other digital logic, or processor circuits associated with at least one memory.

[0066] FIG. 3 illustrates an example of a surface acoustic device with a detection coil and a feedback coil disposed outside the magnetic element, according to one or more exemplary embodiments. The surface acoustic device 300 may include similar components as the surface acoustic device 100, such as the first and second coils 112, 122, and the first and second magnetic elements 110, 120. The surface acoustic device 300 may further include at least one third magnetic element 312 and / or at least one fourth magnetic element 322 including a magnetic material. The magnetic element(s) 312, 322 may include or be made of a magnetizable material that acquires magnetic properties under an external magnetic field. The magnetic element(s) 312, 322 may include, for example, a ferromagnetic material such as iron and / or a ferrimagnetic material(s). The third magnetic element 312 may include a cavity for the first magnetic element 110. The third magnetic element 312 can surround the first magnetic element 110, for example, from a top of the first magnetic element 110 and at least partially from a side of the first magnetic element 110. The fourth magnetic element 322 can include a cavity for the second magnetic element 120, the first coil 112, and / or the second coil 122. The fourth magnetic element 322 can surround the second magnetic element 120, for example, from a bottom of the second magnetic element 120 and at least partially from a side of the second magnetic element 120.

[0067] The top portion 310 of the surface acoustic device 300 may comprise at least the first magnetic element 110. The top portion 310 may further comprise a third magnetic element 312. The top portion 310 may be coupled or configured to be coupled to a surface 102 (not shown). The base portion 320 may comprise at least the first coil 112 and the second coil 122. The base portion 320 may further comprise the second magnetic element 120 and / or the fourth magnetic element 322. Displacement of the surface 102 due to a pressing force provided by a user may be configured to cause movement of the top portion 310 towards the base portion 320. The displacement of the surface 102 may be configured to cause relative movement between the first magnetic element 110 and the first coil 112 to induce a trigger signal in the first coil 112. However, typically, the displacement of the surface 102 may be configured to cause relative movement between at least one magnet and the first coil 112 to induce a trigger signal. 1, a displacement of the surface 102 can be configured to cause relative movement between the second magnetic element 120 and the first coil 112 to induce a trigger signal. Thus, a variety of different arrangements can be used to cause generation of a trigger signal by a user.

[0068] In the base portion 320, the first coil 112 may be disposed closer to the upper portion 310 than the second coil 122, for example, above the second coil 122. By disposing the first coil 112 outside the second magnetic element 120, the wiring length of the first coil 112 can be increased, and the level of EMF induced in the first coil 112 is also increased, resulting in good detection sensitivity. Thus, the sensitivity of user input detection can be improved. Furthermore, the diameter of the first coil 112 can be substantially equal to or larger than the outer diameter(s) of the first and / or second magnetic elements 110, 120, so that most of the magnetic flux can flow through the first coil 112, thereby further increasing the level of induced EMF. However, the second coil 122 can also be disposed closer to the upper portion 310 than the first coil 112, for example, above the first coil 112. The first and second coils 112, 122 may be circular and arranged around the fourth magnetic element 322, or the second magnet, which is generally arranged in a plane defined by the base 104. The base portion 320 is further illustrated on the right by a top view. The first and second coils 112, 122 may be substantially concentric and have substantially the same diameter, so that only the first coil 112 is visible in the top view. However, if the first and second coils 112, 122 have substantially the same diameter, they may only partially overlap when viewed from above. For example, the first and second coils 112, 122 may have the same thickness, i.e., no difference between the inner and outer diameters of each coil.

[0069] Additionally, at least a portion of the first coil 112 and / or at least a portion of the second coil 122 may be configured to surround the second magnetic element 120. When a coil is configured to partially surround the second magnetic element 120, at least one wire of the coil may surround the second magnetic element 120.

[0070] It should also be noted that the fourth magnetic element 322 may surround the second coil 122 from the bottom and sides, but may not surround the first coil 112 from the sides. This allows the size (e.g., diameter) and wire length of the first coil 112 to be further increased, thereby further improving the detection sensitivity. The second magnetic element 120 may take various forms. In the example of FIG. 3, the second magnetic element 120 is surrounded by the fourth magnetic element 322 from the bottom and partially from the sides. However, the second magnetic element 120 may be completely surrounded by the second magnetic element from the sides of the second magnetic element 120. However, the first coil 112 and / or the second coil 122 may be disposed between the second magnetic element 120 and the fourth magnetic element 322. The second magnetic element 120 may be circular (hollow cylindrical) as in FIG. 3, or may be cylindrical. However, the second magnetic element 120 may have any suitable shape, for example a rectangular parallelepiped or a hollow rectangular parallelepiped. The shape of the first and second coils 112, 122 may also be non-circular, for example a rectangular parallelepiped. The first and second coils 112, 122 may comprise planar coils, for example wound or printed, such that the coil wire of a single coil does not overlap in the direction of the axis 130. Alternatively, the first and second coils 112, 122 may be wound such that the coil wire of a single coil also overlaps in the direction of the axis 130 (or only in the direction of the axis 130). According to an exemplary embodiment, the resistance of the first coil 112 may be between 22 and 26 ohms, for example about 24 ohms. The length of the wire of the first coil 112 may be between 3.8 and 4.2 m, for example about 4 m. The first coil has 90 to 110 turns, for example 100 turns. Such selection of coil parameters can improve the sensitivity of detecting user input when the first coil 112 is disposed inside the second magnetic element 120 .

[0071] FIG. 4 illustrates an example of a surface acoustic device with a detection coil disposed inside a circular magnetic element, according to one or more exemplary embodiments. The surface acoustic device 400 may include a top portion 310 and a base portion 320, which may include similar components as described with reference to FIG. 3. However, the first coil 112 may be disposed inside the second magnetic element 120, which may have a circular shape, for example. By disposing the first coil 112 inside the second magnetic element 120, sufficient detection sensitivity can be achieved while reducing the space required to realize a two-coil structure. Thus, at least a portion of the second magnetic element 120 may be configured to surround the first coil 112. This allows sufficient detection sensitivity to be provided, while reducing the thickness of the surface acoustic device, since the first coil 112 and the second coil 122 can be disposed on the same plane, for example, on top of the fourth magnetic element 322. The second coil 122 may be arranged similarly to FIG. 3 such that at least a portion of the second coil 122 is configured to surround the second magnetic element 120. According to an exemplary embodiment, the resistance of the first coil 112 may be between 29 and 33 ohms, for example, about 31 ohms. The length of the wire of the first coil 112 may be between 4.8 and 5.2 m, for example, about 5 m. The first coil 112 may have 340 to 360 turns, for example, 350 turns. This selection of coil parameters may improve the sensitivity of detection of user input when the first coil is placed inside the second magnetic element 120.

[0072] FIG. 5 illustrates an example of a surface acoustic device with a detection coil disposed above a magnetic element, according to one or more exemplary embodiments. The surface acoustic device 500 may include a top portion 310 and a base portion 320, which may include similar components as described with reference to FIG. 3. However, the first coil 112 may be disposed above the second magnetic element 120 and may have a circular shape, for example, as in FIG. 5. This allows the length of the wire of the first coil 112 to be longer, and therefore improves the detection sensitivity. If the second magnetic element 120 is circular, the inner diameter of the first coil 112 may be greater than or equal to the inner diameter of the second magnetic element 120. The outer diameter of the first coil 112 may be less than or equal to the outer diameter of the second magnetic element 120. The first coil 112 may be disposed closer to the top portion 310 than the second magnetic element 120, for example, above the second magnetic element 120. In the top view example of Figure 5, the inner diameter of the first coil 112 is larger than the corresponding diameter of the second magnetic element 120, and the outer diameter of the first coil 112 is smaller than the corresponding diameter of the second magnetic element 120. It should be noted that although the elements of Figures 3, 4, and 5 are illustrated as having particular shapes, entirely similar functionality may be achieved with elements of other shapes.

[0073] FIG. 6 illustrates an example of a block diagram of a surface acoustic device with low-pass filtering of a trigger signal, according to one or more exemplary embodiments. The surface acoustic device 200 may include similar components as described with reference to FIG. 2. The surface acoustic device 200 may further include an amplifier (AMP) 202 between the first coil 112 and the detection circuit. Alternatively, the amplifier 202 may be implemented in the detection circuit 210, or the system may be implemented without the amplifier 202. The detection circuit 210 may include a low-pass filter (LPF) 212. The low-pass filter 212 may be implemented using any suitable circuit. The low-pass filter may include an analog RC (resistor-capacitor) circuit, or, if the detection circuit 210 is implemented (at least in part) using digital logic, the low-pass filter 212 may include, for example, a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter configured to process digital samples obtained by analog-to-digital (A / D) conversion of the (optionally amplified) trigger signal. The low pass filter can be configured to pass haptic frequencies (e.g., 0-10 Hz) and suppress acoustic frequencies (e.g., 20 Hz-20 kHz). The cut-off frequency of the low pass filter can thus be, for example, between 8-20 Hz or between 10-20 Hz. The low pass filter 212 allows for filtering disturbances of the trigger signal. Such disturbances can be caused, for example, by crosstalk from the second coil 122 to the first coil 112 when providing the acoustic and / or feedback signals via the second coil 122. The low pass filter 212 can thus separate the trigger signal from the acoustic and / or feedback signals. According to an exemplary embodiment, the cut-off frequency of the low pass filter 212 is between 8-12 Hz, for example about 10 Hz. This allows for the detection of fast press and release actions occurring in the order of 0.1 seconds while giving a sufficient protection range to the acoustic signal.In a digital implementation, this protection range allows the use of low complexity filters, reducing processing time and therefore providing timely feedback to the user. The detection circuit 210 may further comprise a user input detection unit 214, which may be implemented using analog circuitry or digital signal processing (DSP), as will be further described with reference to FIG.

[0074] As described above, the detection circuit 210 can provide an enable feedback signal (EN_FB) to the feedback circuit 220 in response to detecting a user input. The feedback circuit can comprise or operate as an audio amplifier (AMP). The feedback circuit 220 can comprise a circuit 222 for activating haptic feedback. Alternatively or additionally, an acoustic feedback can be provided. The feedback signal can be obtained from a signal bank, such as, for example, a haptic signal bank 224 and / or an acoustic signal bank. The signal bank can be included in, for example, a memory of the surface acoustic device 200. The feedback circuit 220 can access the memory to obtain the feedback signal from the signal bank upon enabling of the feedback signal. Alternatively or additionally, the feedback signal can include a DC (direct current) voltage or a DC current. If a DC current or voltage is provided in addition to an acoustic feedback signal and / or sound reproduced from an acoustic source, the DC current or voltage can form a component of the electrical signal provided to the second coil 122. By applying a DC current or voltage as haptic feedback, it is possible to generate haptic feedback (e.g., a single bump on the surface 102) that can be easily recognized by a user from other vibrations of the surface 102 caused, for example, by sound reproduction.

[0075] The surface acoustic device 200 may further include a high pass filter (HPF) 204 for filtering the feedback signal. However, the use of the high pass filter 204 is optional. The high pass filter 204 may be used, for example, to reduce the amount of interference caused to the trigger signal when the feedback signal includes an acoustic signal.

[0076] 7 illustrates an example of a raw trigger signal for a press and release action, according to one or more exemplary embodiments. The voltage (mV) of the raw trigger signal is illustrated relative to the time (s) that it is output from the first coil 112. It can be observed that the raw trigger signal contains high frequency components, e.g., due to acoustic interference, superimposed on the voltage induced in the first coil 112 by the user input.

[0077] FIG. 8 illustrates an example of a press and release action of a low-pass filtered trigger signal, according to one or more exemplary embodiments. The peak ("1") of the voltage induced in the first coil 112 occurs when the movement of the surface 102 (coupled to the first magnetic element 110 and / or the first coil 112) towards the base 104 is the fastest, i.e., when pressing the surface 102. Upon release of the surface ("2"), the voltage crosses the zero level, and as the surface 102 moves away from the base, a negative voltage is induced in the first coil 112. In other words, point "1" can be considered to correspond to the maximum speed of movement, and point "2" to the change in direction of movement (zero crossing). It should be noted that the polarity of the voltage may alternatively be arranged differently, for example in an embodiment that does not include integration of the trigger signal, and the voltage may be referenced to a ground level. As will be further explained with reference to FIG. 11, the zero level may be calibrated based on the idle voltage of the first coil 112.

[0078] FIG. 9 illustrates an example of a force curve for a press and release operation, according to one or more exemplary embodiments. The force curve in FIG. 9 was obtained by integration of the trigger signal in FIG. 8. Press force (g) is shown versus time (s). The point of maximum velocity is shown in dashed line. This corresponds to point "1" in the low-pass filtered trigger signal (FIG. 8). Point "3" corresponds to maximum force, which in this example occurs just before the surface 102 is released. Both the trigger signal in FIG. 8 and the force curve in FIG. 9 correspond to a nominal press force of 250 g at 1 Hz.

[0079] FIG. 10 illustrates an example of a functional block diagram of a user input detection circuit, according to one or more exemplary embodiments. The user input detection unit 214 may include one or more of blocks 1010 (peak detector), 1020 (zero crossing detector), and 1030 (force threshold detector). In block 1040, the user input detection unit may determine a level of a feedback enable signal (EN_FB) based on the notification(s) provided by one or more of these blocks. Thus, in some embodiments, all of blocks 1010, 1020, and 1030 may not be present. The user input detection unit 214 may receive a trigger signal from the low pass filter 212 as an input. In this example, the trigger signal is represented by a voltage u (sense voltage, trigger signal voltage), but it will be understood that similar processing may be applied based on the corresponding current.

[0080] Peak Detection The peak detector 1010 may comprise a differentiator circuit 1012 implemented as an analog differentiator circuit or by digital processing (e.g., based on the difference between successive samples of the trigger signal). The differentiator circuit 1012 may provide as an output a derivative (e.g., a first derivative) with respect to time (du / dt). In block 1014, the peak detector 1010 may detect peaks in the trigger signal. Typically, depending on the polarity of the trigger signal (voltage), the peak detector 1010 may be configured to detect peaks at either positive or negative voltages. In the example of FIG. 10, the peak detector 1010 is configured to detect positive voltage peaks (u>0). For example, in block 1014, the peak detector 1014 may determine whether u>0 and whether the derivative of the trigger signal is (substantially) equal to zero (du / dt=0). It should be noted that determining whether du / dt is substantially zero may in fact include determining whether du / dt decreases below a threshold value. In response to detecting a peak at block 1014, the peak detector 1010 may provide a first notification of a user input, for example, by setting a corresponding logic signal (det1) to true (TRUE) at block 1016. In response to detecting a peak, which may correspond to point "1" in FIG. 8, the peak detector 1010 may activate the zero crossing detector 1020 and / or the force threshold detector 1030. However, it should be noted that the zero crossing detector 1020 and / or the force threshold detector 1030 may alternatively be operated independent of any activation control signal provided by the peak detector 1010. For example, two or more of the blocks 1010, 1020, 1030 may operate in parallel and provide their respective notifications independently.

[0081] Zero Crossing Detection In block 1022, the zero crossing detector 1020 may detect a zero crossing of the voltage u. If the zero crossing detector 1020 is activated by the peak detector 1010, the zero crossing detector 1020 may detect the first zero crossing after activation (u=0). Thus, the zero crossing detector does not need to consider the orientation of the zero crossing. This reduces the complexity. However, it is also possible for the zero crossing detector 1020 to operate independently from the peak detector 1010. Thus, the zero crossing detector 1020 may alternatively be configured to detect a zero crossing in response to reaching the zero level from a predefined direction, e.g., the positive side, as shown in FIG. 8. The zero crossing detection may be configured to have a range such that small variations around the zero level within a range do not trigger the zero crossing detection. For example, a zero crossing may be detected only when the zero level is crossed such that the voltage increases or decreases to zero from outside the range. Typically, the zero-crossing detector may provide a second notification of the user input, for example, after a peak in the trigger signal and / or in response to detecting a zero-crossing of the trigger signal in a predetermined direction. The second notification may correspond to detecting a release phase of the user input (see point "2" in FIG. 8). The second notification may be provided in block 1024 by setting a corresponding logic signal (det2) to TRUE.

[0082] Force Threshold Detection The force threshold detector 1030 may comprise an integrator circuit 1032, which may be implemented, for example, as an analog integrator circuit or by digital processing (e.g., based on a sum of samples of the trigger signal over a time interval). The integrator circuit 1032 may output a force (F), an example of which is provided in FIG. 9. Thus, the force signal (F) may include an integrated version of the trigger signal (u). The force threshold detector may be configured to detect whether the force reaches a threshold value. Optionally, the force threshold detector may be configured to verify that the trigger signal is above zero (or, alternatively, below zero). Thus, in block 1034, the force threshold detector 1030 may determine whether the force reaches or exceeds a threshold value (Th1), e.g., whether F>Th1 is satisfied and / or whether the trigger signal is above zero (u>0).

[0083] The threshold Th1 may be preset in the force threshold detector 1030, or in the surface acoustic device in general. Alternatively, the surface acoustic device, e.g., the force threshold detector 1030, may determine the threshold Th1 based on a maximum force level during one or more previous user inputs. For example, the force level may be determined based on an average, weighted average, or minimum of the maximum force levels of multiple previous user inputs. This allows the system to adapt to different levels of peak force that may be caused by different users, as well as gradual changes in peak force due to, for example, aging of parts.

[0084] Typically, the force threshold detector 1030 may provide a third notification of a user input, for example, in response to detecting that the integrated trigger signal (F) reaches or exceeds a threshold value (Th1) and, optionally, in response to detecting that the trigger signal (u) exceeds zero. The third notification may be provided by setting a corresponding logic signal (det3) to true (TRUE) in block 1036. As described above, the force threshold detector 1030 may be activated by the peak detector 1010. In this case, the force threshold detector does not need to monitor the level of the trigger signal (u), which may reduce complexity. However, the force threshold detector 1030 may also be operated independently of the peak detector 1010. This may improve the reliability of the user input detection unit 214, since the force threshold detector 1030 may detect user inputs missed by the peak detector 1010.

[0085] Feedback Enable In block 1040, the user input detector 214 may determine whether to provide a feedback enable signal (EN_FB) to the feedback circuit 220. For example, the user input detector may determine a level (e.g., logical true or false) of the feedback enable signal based on notifications provided by the peak detector 1010, the zero crossing detector 1020, and / or the force threshold detector 1030. Thus, the feedback enable signal may include, for example, a binary signal or a Boolean signal. Providing the feedback enable signal may include setting EN_FB to a level indicating logical true. Providing the feedback enable signal to the feedback circuit 220 may trigger the feedback circuit 220 to activate the feedback signal. Activating the feedback signal may include causing the second coil 122 to provide a voltage or current corresponding to the feedback signal.

[0086] According to an exemplary embodiment, the feedback signal may be enabled in response to receiving notification of a detected event (e.g., a peak of the trigger signal, a zero crossing of the trigger signal, or a crossing of the force threshold Th1) from any of the blocks 1010, 1020, and 1030. Thus, in block 1040, the user input detector 214 may determine the enable feedback signal based on EN_FB=det1 OR det2 OR det3. Alternatively, for example, if the peak detector 1010 is configured to activate the zero cross detector 1020 and / or the force threshold detector 1030, the user input detector 214 may enable the feedback signal in response to receiving notification of a detected event from the zero cross detector 1020 and / or the force threshold detector 1030. Thus, in block 1040, the user input detector 214 may determine the enable feedback signal based on EN_FB=det2 OR det3, or EN_FB=det2 AND det3. Alternatively, the user input detector 214 can enable the feedback signal in response to receiving notification of a detected event from at least one of the peak detector 1010 and the zero crossing detector 1020 or the force threshold detector 1030. For example, EN_FB can be determined in block 1040 based on EN_FB=det1 AND (det2 OR det3), or EN_FB=det1 AND det2 AND det3, thereby trading computational complexity of the user input detector 214 for detection reliability.

[0087] The feedback enable signal may be provided for a predetermined duration, e.g., 10 ms or other preset duration. However, the level of the enable signal may also be set based on combining two or more detection notifications (det1, det2, det3) simultaneously. For example, the detection circuit 210 may be configured to trigger activation of the feedback signal in response to detecting a press of the surface 102 (e.g., by the peak detector 1010). However, the detection circuit 210 may cause the feedback circuit 220 to deactivate the feedback signal in response to detecting a release of the surface 102 (e.g., by the zero cross detector 1020 and / or the force threshold detector 1030). This may provide feedback to the user during user input. This may be performed, for example, by determining EN_FB based on EN_FB=det1 XOR det2. Alternatively, EN_FB may be determined by EN_FB=det1 XOR det3. The feedback enable signal may also be determined based on EN_FB=det1 XOR (det2 AND det3). This allows for improved reliability of release detection by taking into account both the zero crossing (det2) and the force threshold (det3).

[0088] It should be noted that the user input detector 214 may be implemented by analog circuitry, such as, for example, differentiation or integration circuits for generating the signals used for detection, and comparison circuits for performing the detection. Alternatively, or in addition, digital logic or processing circuitry having associated program code may be used to implement at least some of the functionality of the user input detector 214.

[0089] FIG. 11 illustrates an example of a block diagram of a detection circuit with a threshold for enabling zero-level calibration and user input detection, according to one or more exemplary embodiments. The detection circuit 210 can include a low-pass filter 212 and a user input detection unit 214. The detection circuit may further include a zero-level calibration block 216. The zero-level calibration block 216 may be configured to calibrate the zero level of the trigger signal, for example, based on an idle voltage of the first coil 112. The zero-level calibration may include, for example, subtracting the idle voltage of the first coil 112 from the trigger signal. The zero-level calibration is useful, for example, when the user input detection unit 214 uses an integrated trigger signal for threshold detection (Th1) of force. For example, calibrating the zero level before providing the trigger signal (u) to the integration circuit 1032 ensures that the integrated force curve is maximized at a point corresponding to a maximum force, so that the point of maximum force can be detected based on the threshold (Th1).

[0090] Furthermore, the user input detection can be thresholded by block 218 such that the user input detection unit 214 is activated in response to detecting that the (optionally zero-level calibrated) trigger signal exceeds or reaches the threshold (Th2). Thus, the detection circuit 210 can continue to monitor the level of the trigger signal after detecting the user input (branch “No”) and activate the user input detection unit 214 when the trigger signal again reaches or exceeds the threshold (Th2). This can avoid slight fluctuations near the zero level that would cause the user input detection to be activated. It can also reduce power consumption because the user input detection unit 241 can be activated only when there is a high probability that there is a user input to be detected. Also, when the user input detection unit 214 is not activated, it can be in a low power consumption state. For example, in the case of an analog circuit, the system can prevent a current corresponding to the trigger signal from flowing through the user detection circuit. In the case of a digital process, the operation performed by the user input detection unit 214 can be temporarily disabled, thereby reducing power consumption. The threshold Th2 of block 218 may be lower than the threshold Th1 of the force threshold detector 1030 (see block 1034) and may be lower in absolute value overall.

[0091] 10, in response to detection of a user input by the user input detection portion 214, the detection circuit 210 may again return to monitoring the level of the trigger signal at block 218. Upon returning to operation 218, the user input detection notification(s) may be set to a level indicating a logical FALSE. This may allow a new detection operation to be initiated regardless of previous detections by the user input detection portion 214.

[0092] 12 illustrates an example of an apparatus comprising multiple surface acoustic devices, according to one or more exemplary embodiments. The surface acoustic device 1200 may comprise a surface 102 and multiple surface acoustic devices 100 (100-1, 100-2, 100-3, 100-4), for example, at corners of the surface 102. The surface acoustic devices 100-1, 100-2, 100-3, 100-4 may be connected to a detection circuit 210. For example, the detection circuit 210 may be connected to multiple first coils 112 corresponding to different surface acoustic devices 100-1, 100-2, 100-3, 100-4. Each surface acoustic device 100-1, 100-2, 100-3, 100-4 may generate a trigger signal in response to a movement of the surface 102, as described above, and the detection circuit 210 may receive the trigger signal from each first coil 112. Thus, the sensed touch may include a sum of the corner component sense signals. The detection circuit 210 may detect a user input on the surface 102 based on these trigger signals. For example, the detection circuit 210 may trigger the feedback circuit 220 to activate a feedback signal in response to detecting a user input based on at least one of the trigger signals. For example, the detection circuit may provide a feedback enable signal (EN_FB) to the feedback circuit 220 if at least one of the trigger signals meets a condition for detecting a user input. Alternatively, the user input may be detected in response to detecting a combination of trigger signals that meets a condition for a user input, such as when each of the trigger signals meets a condition. Thus, the feedback circuit 220 may be configured to activate a feedback signal of the second coil 122 of the surface acoustic device 100-1, 100-2, 100-3, 100-4 in response to the detection of the user input by the detection circuit. The same feedback signal may also be provided to different surface acoustic devices 100-1, 100-2, 100-3, 100-4. Thus, multiple identical feedback signals may be provided to different surface acoustic devices 100-1, 100-2, 100-3, 100-4.Alternatively, the feedback signals provided to the different surface acoustic devices 100-1, 100-2, 100-3, 100-4 may be different.

[0093] It is further noted that pressing the surface 102 at different locations on the surface 102 may generate different trigger signals in the surface acoustic devices 100-1, 100-2, 100-3, 100-4. For example, pressing the surface 102 at location 1202 may generate a stronger trigger signal in the first coil 112 of the surface acoustic device 100-1 than in the first coil 112 of the surface acoustic device 100-4. Thus, based on the characteristics of the trigger signal, the location of the user input on the surface can be estimated. For example, the detection circuit 210 can be configured to detect the location of the user input based on the voltage or current levels induced in the first coils 112 of the different surface acoustic devices 100-1, 100-2, 100-3, 100-4. For example, different locations on the surface can be mapped to different user inputs to adjust different aspects of a system configured to be controlled by the surface acoustic device 1200.

[0094] The feedback signals provided to the coil 122 may be determined based on the location of the user input. For example, a stronger feedback signal may be provided to a surface acoustic device(s) (e.g., 100-1) that is relatively closer to the location of the user input. Thus, the strength of the feedback signal for a particular surface acoustic device may be determined based on the distance of that surface acoustic device from the location of the user input. This may reduce power consumption by avoiding or attenuating feedback provided by surface acoustic device(s) (e.g., 100-4) that are farther from the user input.

[0095] Furthermore, even if the feedback signals are the same, the feedback signal can be determined based on the location of the user input. This allows for providing feedback specific to the user input. For example, by pressing the surface 102 at position 1202, the user can be provided with a first acoustic or haptic feedback by one or more of the surface acoustic devices 100-1, 100-2, 100-3, 100-4. However, if the user presses the surface 102 at another position, for example, position 1204, a different acoustic or haptic feedback can be provided. For example, if the surface acoustic device 1200 is configured to control the volume of sound reproduction by the surface acoustic device 1200, the user can be allowed to increase the volume by pressing the surface on the left side (the side relatively closer to the surface acoustic device 100-1 or 100-3) and decrease the volume by pressing the surface on the right side (the side relatively closer to the surface acoustic device 100-2 or 100-4). Different acoustic and / or haptic feedback can then be provided based on whether the user wants to turn the volume up (e.g., by pressing the surface at location 1202) or turn the volume down (e.g., by pressing the surface at location 1204).

[0096] This may be performed, for example, based on a mapping between a location of a user input on the surface 102 and at least one feedback signal. Such a mapping may be stored in the surface acoustic device 1200, for example, along with the haptic signal bank 224 or the acoustic signal bank. The surface 102 may be divided, for example, into multiple regions, each region being mapped to at least one feedback signal. It should be noted that the regions of the surface 102 may be represented in the memory of the surface acoustic device 1200 by corresponding threshold levels of trigger signals, rather than physical regions on the surface 102.

[0097] The mapping between regions and feedback signals may be configurable. For example, if the surface 102 includes a touch screen, a user may be able to configure feedback signals associated with different regions and / or different applications controllable by user input. For example, user input at the same location on the surface 102 may be configured to provide different feedback depending on the application currently controllable by the surface acoustic device 1200. Alternatively, the mapping may be configured by another device providing the mapping to the surface acoustic device 1200, for example, via a wireless communication interface. Typically, the surface acoustic device 1200 may receive notification of a mapping between the location(s) of the user input on the surface 102 and the feedback signal(s).

[0098] It should be noted that although four surface acoustic devices 100-1, 100-2, 100-3, 100-4 are illustrated in FIG. 12, the surface acoustic device 1200 may generally comprise any number of surface acoustic devices 100. In the simplest case, where there is one surface acoustic device, the panel (surface 102) may be a button. By using multiple surface acoustic devices 100, it is possible to detect intermediate user inputs at positions between the surface acoustic devices 100. The user may also select a use case (e.g., an application) from the touch panel (surface 102) and thereby configure the acoustic and / or haptic feedback. This allows for the generation of acoustic and / or haptic feedback suited to a particular use case. This also allows for personalization of the acoustic and / or haptic feedback.

[0099] 13 illustrates an example of an apparatus configured to implement one or more exemplary embodiments. The apparatus 1300 may comprise at least one processor 1302. The at least one processor 1302 may comprise one or more of a variety of processing devices or processor circuits including, for example, a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuit with or without an associated DSP, or an integrated circuit such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware (HW) accelerator, a special purpose computer chip, or the like.

[0100] The device 1300 may further comprise at least one memory 1304. The at least one memory 1304 may be configured to store, for example, computer program code, such as operating system software and application software. The at least one memory 1304 may include one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination thereof. For example, the at least one memory 1304 may be embodied as a magnetic storage device (such as a hard disk drive, a floppy disk, a magnetic tape, etc.), a magneto-optical storage device, or a semiconductor memory (such as a mask ROM, a PROM (programmable ROM), an EPROM (erasable PROM), a flash ROM, a RAM (random access memory), etc.).

[0101] The device 1300 may further comprise a communication interface (not shown) configured to enable the device to transmit and / or receive information, such as, for example, a library or bank of feedback signals or configuration information including a mapping between different user inputs (e.g., positions on the surface of the surface acoustic device) and different feedback signals. Alternatively, such information may be pre-configured in the device 1300. The communication interface may comprise, for example, a short-range wireless network connection (e.g., Bluetooth or Wi-Fi), or a cellular communication interface, for example according to the 3rd Generation Partnership Project (3GPP) specifications. The device 1300 may further comprise a user interface (not shown). The user interface may comprise, for example, the surface 102.

[0102] If the apparatus 1300 is configured to implement some functionality, then certain elements and / or components of the apparatus 1300 may be configured to implement this functionality, such as, for example, the at least one processor 1302 and / or the at least one memory 1304. Further, if the at least one processor 1302 is configured to implement some functionality, then the functionality may be implemented using, for example, program code 1306 contained within the at least one memory 1304.

[0103] The functions described herein may be performed, at least in part, by one or more computer program product components, such as software components. According to an embodiment, the apparatus comprises a processor or processor circuit, such as, for example, a microcontroller, configured to perform the described operation and functional embodiments by the program code when executed. Alternatively, or in addition, the functions described herein may be performed, at least in part, by one or more hardware logic components. For example, but not limited to, exemplary types of hardware logic components that may be used include field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), complex programmable logic devices (CPLDs), and graphic processing units (GPUs).

[0104] The apparatus 1300 comprises means for performing at least one exemplary embodiment described herein. In one example, the means comprises at least one processor 1302 and at least one memory 1304 including program code 1306 configured to cause the apparatus 1300 to perform an exemplary embodiment when executed by the at least one processor. Alternatively or additionally, the means may comprise one or more of the structural elements of the figure, such as, for example, the first and second coils 112, 122. Although the apparatus 1300 is illustrated as a single device, it will be understood that, if desired, the functionality of the apparatus 1300 may be distributed across multiple devices to perform the exemplary embodiment, for example, by distributed computing.

[0105] FIG. 14 illustrates an example of a method for providing audio or haptic feedback to a user, according to one or more exemplary embodiments.

[0106] At 1401, the method may include detecting a user input at a surface based on a trigger signal comprising a voltage or current induced in a first coil by a displacement of the surface by a user.

[0107] At 1402, the method may include activating a feedback signal in response to detecting a user input.

[0108] At 1403, the method may include generating a magnetic field with a second coil to cause or vary a movement of the surface in response to activation of the feedback signal.

[0109] Further features of the method result directly from the functions and parameters of the devices 100, 200, 300, 400, 500, 1200 or 1300, as described, for example, in the appended claims and throughout the specification, and therefore will not be repeated here. Different variants of the method are also applicable, as explained in connection with the various exemplary embodiments.

[0110] The apparatus may perform or be configured to perform any aspect of the methods described herein. Additionally, the computer program may include instructions that, when executed, cause the apparatus to perform any aspect of the methods described herein. Additionally, the apparatus may include means for performing any aspect of the methods described herein. According to an exemplary embodiment, the means comprises at least one processor and at least one memory including program code, the at least one processor and the program code, when executed by the at least one processor, configured to cause any aspect of the methods to be performed.

[0111] The ranges or device values ​​given herein may be expanded or modified without sacrificing the intended effect, and any embodiment may be combined with other embodiments unless expressly prohibited.

[0112] Although the present subject matter has been described in language specific to structural features and / or operations, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or operations described above. Rather, the specific features and operations described above are disclosed as example forms of implementing the claims, and other equivalent features and operations are intended to be within the scope of the claims.

[0113] It will be understood that the advantages and benefits described above may relate to one embodiment or to multiple embodiments. The embodiments are not limited to those that solve any or all of the problems described or those that have any or all of the benefits and advantages described. Further, it will be understood that references to "an" or "an" item may refer to one or more of those items.

[0114] The steps or actions of the methods described herein may be performed in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any method without departing from the scope of the subject matter described herein. Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described above to form further embodiments without losing the desired effect.

[0115] As used herein, the term "comprising" is used to mean including specified methods, blocks, or elements, but such blocks or elements do not constitute an exclusive list and the methods or apparatus may include additional blocks or elements.

[0116] As used in this application, the term "circuitry" may refer to one or more of: (1) a hardware-only circuit implementation (e.g., an implementation with only analog and / or digital circuitry); and (2) a combination of hardware circuitry and software, such as (i) a combination of analog and / or digital hardware circuitry and software / firmware; and (ii) any portion of hardware processor(s) and software (e.g., digital signal processor(s)), software, and memory(s) that cooperate to cause an apparatus to perform various exemplary embodiments; and (3) hardware circuit(s) and processor(s), such as a microprocessor(s) or portion of a microprocessor(s) that requires software (e.g., firmware) to operate, but the software may not be present when not necessary for operation.

[0117] It will be understood that the above description is given by way of example only, and that various modifications may be made by those skilled in the art. The above specification, examples, and data provide a complete description of the structure and use of the exemplary embodiments. Although the above describes various embodiments with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art may make numerous modifications to the disclosed embodiments without departing from the scope of the present specification.

Claims

1. a detection circuit connected to the first coil, the detection circuit configured to detect a user input at the surface based on a trigger signal comprising a voltage or current induced in the first coil by a user's displacement of the surface; and an upper portion comprising a first permanent magnet, and a base portion comprising the first coil and a second coil, wherein the displacement of the surface by the user is configured to cause movement of the upper portion towards the base portion, and the displacement of the surface is configured to cause relative movement between the first permanent magnet and the first coil to induce the voltage or current in the first coil; a feedback circuit connected to the second coil, the feedback circuit configured to activate a feedback signal in response to detection of the user input by the detection circuit, the second coil configured to cause or vary movement of the surface based on a magnetic field configured to be generated by the second coil upon activation of the feedback signal; An apparatus comprising:

2. 2. The device of claim 1, wherein the first coil and the second coil are substantially concentric and have substantially the same diameter, and the first coil is positioned closer to the upper portion than the second coil.

3. 3. The device of claim 1, wherein the base portion further comprises at least one second permanent magnet, and wherein at least a portion of the first coil and / or at least a portion of the second coil is configured to surround the at least one second permanent magnet.

4. 4. The apparatus of claim 3, wherein the resistance of the first coil is between 22 and 26 ohms, and the length of the wire of the first coil is between 3.8 and 4.2 meters.

5. 4. The apparatus of claim 3, wherein at least a portion of the at least one second permanent magnet is configured to surround the first coil and at least a portion of the second coil is configured to surround the at least one second permanent magnet.

6. 6. The apparatus of claim 5, wherein the resistance of the first coil is between 29 and 33 ohms, and the length of the wire of the first coil is between 4.8 and 5.2 meters.

7. The apparatus of claim 1 or 2, wherein the feedback signal comprises a DC voltage or a DC current.

8. The device of claim 1 or 2, further comprising a low pass filter configured to filter the trigger signal, the low pass filter configured to pass tactile frequencies and suppress acoustic frequencies.

9. 9. The apparatus of claim 8, wherein the cutoff frequency of the low-pass filter is between 8 and 12 Hz.

10. The detection circuit further comprises: providing a first indication of the user input in response to detecting a peak in the trigger signal; and / or providing a second indication of the user input in response to detecting a zero crossing of the trigger signal after the peak of the trigger signal.

3. The device according to claim 1 or 2, configured to:

11. The detection circuit further comprises: differentiating the trigger signal to obtain a derivative of the trigger signal; providing the first indication of the user input in response to detecting that the trigger signal is above zero and the derivative of the trigger signal is substantially equal to zero. The apparatus of claim 10 configured to:

12. The detection circuit further comprises: integrating the trigger signal; providing a third notification of the user input in response to detecting that the integrated trigger signal reaches or exceeds a first threshold and the trigger signal is above zero; 3. The device according to claim 1 or 2, configured to:

13. The detection circuit further comprises: triggering the feedback circuit to activate the feedback signal in response to at least one of the first indication of the user input, the second indication of the user input, or the third indication of the user input; The apparatus of claim 10 configured to:

14. The detection circuit further comprises: calibrating a zero level of the trigger signal based on an idle voltage of the first coil; 3. The device according to claim 1 or 2, configured to:

15. The detection circuit further comprises: activating the detection of the user input in response to detecting the trigger signal reaching or exceeding a second threshold.

3. The device according to claim 1 or 2, configured to:

16. 3. The device of claim 1, wherein the detection circuit is connected to a plurality of the first coils, the detection circuit is further configured to detect the user input at the surface based on a plurality of trigger signals corresponding to the plurality of the first coils, and the feedback circuit is further configured to activate a plurality of the feedback signals for the plurality of the second coils in response to the detection of the user input by the detection circuit.

17. 17. The apparatus of claim 16, wherein the detection circuitry is further configured to detect a position of the user input on the surface based on a voltage or current level induced by the user input in the first plurality of coils.

18. 20. The apparatus of claim 17, wherein the feedback circuitry is further configured to determine the plurality of feedback signals based on the position of the user input on the surface.

19. 20. The apparatus of claim 18, wherein the feedback circuitry is further configured to determine the plurality of feedback signals based on a mapping between the position of the user input on the surface and at least one feedback signal.

20. 20. The apparatus of claim 19, wherein the feedback circuitry is further configured to receive notification of the mapping between the position of the user input on the surface and the at least one feedback signal.

21. 17. The apparatus of claim 16, wherein the multiple feedback signals are identical.

22. detecting a user input at the surface based on a trigger signal, the trigger signal comprising a voltage or current induced in a first coil by a displacement of the surface by a user; filtering the trigger signal with a low pass filter configured to pass tactile frequencies and suppress acoustic frequencies; activating a feedback signal in response to detecting the user input; generating a magnetic field by a second coil in response to activation of the feedback signal to cause or vary movement of the surface; A method comprising:

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