Piezoelectric sensing devices

Abstract

A device for piezoelectric sensing is provided. According to an embodiment, a device includes a touch surface, a plurality of piezoelectric sensors, and a wake-up circuit, wherein the plurality of piezoelectric sensors includes at least a first subset of piezoelectric sensors and a second subset of piezoelectric sensors. The wake-up circuit can be configured to: obtain an electrical signal from each of the plurality of piezoelectric sensors; assign a positive sign to the electrical signal obtained from the first subset of piezoelectric sensors and a negative sign to the electrical signal obtained from the second subset of piezoelectric sensors; generate a sum signal by summing the obtained electrical signals according to the assigned signs; compare the sum signal to a preconfigured condition; and provide a wake-up signal in response to the sum signal satisfying the preconfigured condition.

Description

Technical Field

[0001] The present disclosure relates to a device, and more particularly, to a device of a piezoelectric sensor for touch sensing. Background Art

[0002] Piezoelectric sensors can be used to provide tactile effects to users, to sense touch, or both. For example, a user can use an electronic computing device, such as a laptop, through a touch surface. Piezoelectric sensors can be used to convert the pressure applied by the user to the touch surface into electrical signals, and appropriate electronic circuitry can analyze the electrical signals to convert them into input commands. It might be desirable to have the touch surface always enabled so that the user can use the device. However, this can introduce other issues, such as increased power consumption. Summary of the Invention

[0003] This summary is provided to introduce a selection of inventive concepts in a simplified form, which are further described in the detailed description below. 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.

[0004] The object of the present invention is to provide a device for piezoelectric sensing. These and other objects are achieved by the features of the independent claims. Further embodiments are apparent from the dependent claims, the description and the drawings.

[0005] According to a first aspect, a device includes: a touch surface; a plurality of piezoelectric sensors mechanically coupled to the touch surface, each of the plurality of piezoelectric sensors configured to convert a force applied to the piezoelectric sensor via the touch surface into an electrical signal, wherein the plurality of piezoelectric sensors includes at least a first subset of piezoelectric sensors and a second subset of piezoelectric sensors; and a wake-up circuit electrically coupled to the plurality of piezoelectric sensors, wherein the wake-up circuit is configured to: obtain the electrical signal from each of the plurality of piezoelectric sensors; assign a positive sign to the electrical signal obtained from the piezoelectric sensors of the first subset and a negative sign to the electrical signal obtained from the piezoelectric sensors of the second subset; generate a sum signal by summing the obtained electrical signals according to the assigned signs; compare the sum signal to a preconfigured condition; and provide a wake-up signal in response to the sum signal satisfying the preconfigured condition. The device can provide the wake-up signal, for example, when a user presses the touch surface, rather than providing the wake-up signal in response to a common-mode signal in the piezoelectric sensors.

[0006] In an implementation form of the first aspect, the preconfigured condition comprises at least one preconfigured threshold value for the sum signal.The device is capable of, for example, effectively distinguishing between a signal due to local pressure in the piezoelectric sensor and a common mode signal.

[0007] In another implementation form of the first aspect, the at least one preconfigured threshold value comprises a maximum value of the sum signal, a minimum value of the sum signal, and / or a maximum value of the absolute value of the sum signal. The device can, for example, effectively and comprehensively distinguish between a signal due to local pressure in the piezoelectric sensor and a common-mode signal.

[0008] In another implementation form of the first aspect, the device is further configured to adjust at least one preconfigured threshold in response to the sum signal satisfying a threshold.The device can, for example, adjust the at least one preconfigured threshold for consecutive wake-up events.

[0009] In another implementation form of the first aspect, the wake-up circuit further includes a plurality of switches, wherein each switch of the plurality of switches is electrically coupled to a piezoelectric sensor of the plurality of piezoelectric sensors and is configured to assign the piezoelectric sensor to either the piezoelectric sensors of the first subset or the piezoelectric sensors of the second subset. The device is capable of, for example, changing the assignment of the piezoelectric sensors between the first subset and the second subset.

[0010] In another implementation form of the first aspect, the plurality of switches comprises a preconfigurable or programmable selection switch group.The device is capable of changing the distribution of the piezoelectric sensors between the first subset and the second subset, for example using software and / or other effective means.

[0011] In another implementation form of the first aspect, the plurality of piezoelectric sensors are geometrically arranged such that each piezoelectric sensor of the first subset of piezoelectric sensors that is not at an edge of the plurality of piezoelectric sensors is adjacent to at least one piezoelectric sensor of the second subset of piezoelectric sensors.

[0012] In another implementation form of the first aspect, the piezoelectric sensors of the first subset and the piezoelectric sensors of the second subset are geometrically arranged in an alternating pattern.

[0013] In another implementation form of the first aspect, the wake-up circuit is further configured to: assign a weighting factor to each electrical signal obtained from the plurality of piezoelectric sensors; and generate a sum signal by summing the obtained electrical signals according to the assigned signs and the assigned weighting factors.

[0014] In another implementation form of the first aspect, the device further includes a control circuit electrically coupled to the plurality of piezoelectric sensors and the wake-up circuit, wherein the wake-up circuit is further configured to provide a wake-up signal to at least the control circuit, and wherein the control circuit is configured to: switch to the active mode in response to receiving the wake-up signal in the standby mode.

[0015] In another implementation form of the first aspect, the control circuit is further configured to: when in the active mode, obtain an electrical signal from each of the plurality of piezoelectric sensors, and locate the object on the touch surface based on the obtained electrical signal.

[0016] It should be understood that the implementation forms of the first aspect described above can be used in combination with each other. Several implementation forms can be combined to form another implementation form.

[0017] According to a second aspect, an electronic computing device comprises the device according to the first aspect, wherein the electronic computing device is configured to be awakened from a sleep mode in response to a wake-up signal.

[0018] According to a third aspect, a method includes: obtaining an electrical signal from each piezoelectric sensor of a plurality of piezoelectric sensors, wherein the plurality of piezoelectric sensors are mechanically coupled to a touch surface, each piezoelectric sensor of the plurality of piezoelectric sensors being configured to convert a force applied to the piezoelectric sensor via the touch surface into an electrical signal, wherein the plurality of piezoelectric sensors include at least a first subset of piezoelectric sensors and a second subset of piezoelectric sensors; assigning a positive sign to the electrical signal obtained from the piezoelectric sensors of the first subset, and assigning a negative sign to the electrical signal obtained from the piezoelectric sensors of the second subset; generating a sum signal by summing the obtained electrical signals according to the assigned signs; comparing the sum signal to a preconfigured condition; and providing a wake-up signal in response to the sum signal satisfying the preconfigured condition.

[0019] In an implementation form of the third aspect, the preconfigured condition comprises at least one preconfigured threshold value for the sum signal.

[0020] In another implementation form of the third aspect, the at least one preconfigured threshold value includes a maximum value of the sum signal, a minimum value of the sum signal, and / or a maximum value of an absolute value of the sum signal.

[0021] It should be understood that the implementation forms of the third aspect described above can be used in combination with each other. Several implementation forms can be combined to form another implementation form.

[0022] Many of the additional features will be better understood as they become more readily apparent by reference to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the following, exemplary embodiments are described in more detail with reference to the accompanying drawings, in which:

[0024] Figure 1 shows a cross-sectional view of a device according to an embodiment;

[0025] Figure 2 FIG2 shows a schematic diagram of a device providing a wake-up signal to another device according to an embodiment;

[0026] Figure 3 shows a schematic diagram of the apparatus further comprising a control circuit;

[0027] Figure 4 shows a plurality of piezoelectric sensors according to an embodiment;

[0028] Figure 5 shows a plurality of piezoelectric sensors according to another embodiment;

[0029] Figure 6 A plurality of piezoelectric sensors 102 are shown according to another embodiment;

[0030] Figure 7 shows a schematic diagram of a wake-up circuit according to an embodiment;

[0031] Figure 8 shows a schematic diagram of a wake-up circuit according to another embodiment;

[0032] Figure 9 shows a graph of a sum signal according to an embodiment;

[0033] Figure 10 shows a flow chart of a method according to an embodiment;

[0034] Figure 11 A schematic diagram illustrating an electronic computing device according to an embodiment; and

[0035] Figure 12 A schematic diagram of an electronic computing device according to another embodiment is shown.

[0036] Hereinafter, the same reference numerals are used to denote the same parts in the drawings. DETAILED DESCRIPTION

[0037] In the following description, reference is made to the accompanying drawings, which constitute a part of this disclosure and illustrate specific aspects that may be involved in this disclosure. It should be understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of this disclosure. Therefore, the following detailed description should not be regarded as a description in a limiting sense, as the scope of the invention is defined by the appended claims.

[0038] For example, it should be understood that disclosures related to a method also apply to corresponding devices or systems configured to perform the method, and vice versa. For example, if specific method steps are described, the corresponding device may include units for performing the described method steps, even if such units are not explicitly described or shown in the accompanying drawings. On the other hand, for example, if a specific device is described based on functional units, the corresponding method may include steps for performing the described functions, even if the steps are not explicitly described or shown in the accompanying drawings. In addition, it should be understood that unless otherwise stated, the features of the various example aspects described herein may be combined with each other.

[0039] Figure 1 A schematic cross-sectional view of a device 100 according to an embodiment is shown.

[0040] According to an embodiment, device 100 includes a touch surface 101 and a plurality of piezoelectric sensors 102 mechanically coupled to touch surface 101. Each of the plurality of piezoelectric sensors 102 may be configured to convert a force applied to the piezoelectric sensor via touch surface 101 into an electrical signal. The plurality of piezoelectric sensors 102 may include at least a first subset 103 of piezoelectric sensors and a second subset 104 of piezoelectric sensors.

[0041] Herein, the piezoelectric sensors of the first subset 103 may be referred to as the first subset, and the piezoelectric sensors of the second subset 104 may be referred to as the second subset.

[0042] The touch surface 101 may also be referred to as a layer, a surface layer, a touch interface surface, or a touch interface layer. The touch surface 101 may be part of a touch user interface. The touch surface 101 may be part of a touch pad or keys / buttons of a laptop or a touch screen, for example.

[0043] Piezoelectric sensors can also be called piezoelectric elements, piezoelectric transducers, etc.

[0044] Touch surface 101 may include a first side and a second side. The first side may be at least partially unobstructed. A user may touch the first side with an object 106, such as a finger. Object 106 may be, for example, a user's finger, any other part of a person's body, a stylus, or some other object held by the user. If object 106 is a finger, the user may be wearing a glove, and only the fabric of the glove may be in direct contact with touch surface 101.

[0045] A plurality of piezoelectric sensors may be arranged on the second side of touch surface 101. Piezoelectric sensors 102 may be located immediately adjacent to, proximate to, or spaced apart from the second side. Each of piezoelectric sensors 102 may be configured to convert mechanical stress in the piezoelectric sensor caused by a force applied by object 106 to the first side of touch surface 101 into a voltage. Mechanical stress may also be referred to as stress. The voltage may also be referred to as an electrical voltage, a stress-induced voltage, or the like. The voltage may be proportional to the mechanical stress.

[0046] Each piezoelectric sensor can include a piezoelectric material. The piezoelectric material can convert the force / stress applied to the piezoelectric sensor into a charge buildup in the material through the piezoelectric effect, which can be detected as a voltage across the piezoelectric material. This can also be referred to as piezoelectricity.

[0047] The voltage induced across a piezoelectric sensor in plurality of piezoelectric sensors 102 may be proportional to the rate of change of force / pressure applied to touch surface 101 by object 106 .

[0048] Each of the plurality of piezoelectric sensors 102 may be further configured to convert a voltage applied to the piezoelectric sensor into mechanical stress through the piezoelectric effect. Therefore, when a driving voltage is applied to the piezoelectric sensor, a tactile effect may be sensed into the touch surface 101.

[0049] As used herein, "two elements are mechanically coupled" may mean that there is a mechanical connection between the two elements. The two elements may, for example, be in contact with each other, or may be mechanically connected via other elements. For example, each of the plurality of piezoelectric sensors 102 may be in contact with touch surface 101, or one or more other elements may be present between the piezoelectric sensors and touch surface 101. Thus, when a force is applied to touch surface 101 by object 106 touching touch surface 101, the force may be transmitted to piezoelectric sensors 102.

[0050] The device 100 may further include a wake-up circuit 105 electrically coupled to the plurality of piezoelectric sensors 102 .

[0051] The wake-up circuit 105 may include any electrical / electronic circuit configured to implement the functionality disclosed herein. The wake-up circuit 105 need not be implemented as a separate unit / module / device. Instead, the wake-up circuit 105 may refer to any portion of the device 100 configured to implement the functionality disclosed herein.

[0052] The wake-up circuit 105 may be configured to obtain an electrical signal from each of the plurality of piezoelectric sensors 102 .

[0053] The electrical signal may include, for example, a voltage or a current.

[0054] The wake-up circuit 105 may be configured to obtain the electrical signal, for example substantially continuously or as discrete samples.

[0055] The wake-up circuit 105 may be further configured to assign a positive sign to the electrical signals obtained from the first subset of piezoelectric sensors and to assign a negative sign to the electrical signals obtained from the second subset of piezoelectric sensors.

[0056] In this document, the symbol may also be referred to as polarity, voltage polarity, etc.

[0057] The wake-up circuit 105 may be configured to assign a sign, for example, by connecting the piezoelectric sensor to the electrical connections of the wake-up circuit 105. For example, the first subset 103 may be connected to the wake-up circuit 105 in such a way that a signal (e.g., voltage or current) obtained from the first subset 103 is positive, while the second subset 104 may be connected to the wake-up circuit 105 in such a way that a signal obtained from the second subset 104 is negative, and vice versa.

[0058] The wake-up circuit 105 may be further configured to generate a sum signal by summing the obtained electrical signals according to the assigned signs, and compare the sum signal with a preconfigured condition.

[0059] The wake-up circuit 105 can be configured to sum the signals using, for example, any suitable electrical / electronic components. For example, the wake-up circuit 105 can include a summing amplifier configured to sum the signals. Alternatively, the wake-up circuit 105 can include a passive summing circuit in which a window comparator or a pair of comparators compares the summed signals to detect whether a trigger level is exceeded.

[0060] The wake-up circuit 105 may be further configured to provide a wake-up signal in response to the sum signal satisfying a preconfigured condition.

[0061] Herein, a wake-up signal may refer to any signal capable of waking up another device / module / component from an inactive mode.

[0062] According to an embodiment, the preconfigured condition comprises at least one preconfigured threshold value for the sum signal.

[0063] According to an embodiment, the at least one preconfigured threshold value comprises a maximum value of the sum signal, a minimum value of the sum signal and / or a maximum value of the absolute value of the sum signal.

[0064] The wake-up circuit 105 may be configured to provide a wake-up signal in response to the sum signal being greater than a maximum value. Alternatively or additionally, the wake-up circuit 105 may be configured to provide a wake-up signal in response to the sum signal being less than a minimum value. Alternatively or additionally, the wake-up circuit 105 may be configured to provide a wake-up signal in response to the absolute value of the sum signal being greater than a maximum value of the absolute value of the sum signal.

[0065] In other embodiments, the preconfigured conditions may include other conditions. For example, the wake-up circuit 105 may be configured to provide a wake-up signal in response to the sum signal being greater than / less than a threshold value N times within a preconfigured time period, where N can be any natural number. For example, if N=2, the user can use a double-click gesture on the touch surface 101 (i.e., quickly touching the touch surface 101 twice) to wake up the device 100. Additionally or alternatively, the wake-up circuit 105 may include other signal preprocessing, such as bandwidth filtering, to suppress signals that are outside the expected signal range. This can be achieved by, for example, adding low-pass filtering to suppress frequencies higher than the frequency required to trigger wake-up (even if the amplitude exceeds the trigger level), or adding high-pass filtering to suppress frequencies lower than the required frequency (e.g., slow signal drift caused by temperature changes in the offset of the sensor signal).

[0066] It should be understood that the wake-up circuit 105 can substantially continuously perform any of the operations disclosed herein. For example, if the wake-up circuit 105 is implemented as an analog electronic circuit, the wake-up circuit 105 can substantially continuously perform the functions disclosed herein.

[0067] According to an embodiment, the electronic computing device comprises device 100. The electronic computing device may be configured to wake up from a sleep mode in response to a wake-up signal.

[0068] Device 100 can wake up other components / devices using a wake-up signal provided by wake-up circuit 105. Wake-up circuit 105 can eliminate so-called common-mode signals. Herein, a common-mode signal may refer to a signal obtained from multiple piezoelectric sensors at substantially the same time. A common-mode signal can be caused by, for example, mechanical vibration or other mechanical or electrical interference common to multiple / all piezoelectric sensors. For example, while in transit, an electronic computing device including device 100, such as a laptop, may be subjected to vibration. Such vibration may couple to the touch surface and thereby induce signals in multiple piezoelectric sensors 102. However, because the signal is substantially the same for all piezoelectric sensors, wake-up circuit 105 can eliminate the signal without causing other components in the electronic computing device to wake up. On the other hand, when a user applies pressure to touch surface 101 while the electronic computing device is in sleep mode, the signals provided by the piezoelectric sensors differ from each other because the pressure applied by the user is more localized. Therefore, the wake-up circuit does not eliminate the signals from the piezoelectric sensors, but instead provides a wake-up signal that can be used, for example, to wake up components of the electronic computing device.

[0069] Device 100 can reduce the number of false triggers that wake up the system in which device 100 is located. For example, separate circuitry used to analyze touch input provided by a user to touch surface 101 can be put into sleep mode more frequently, which can reduce power consumption and improve battery life. Lower false trigger counts can further reduce interrupt events and false triggers in the host system in which device 100 is located.

[0070] The wake-up trigger level can be configured to a lower value, which increases sensitivity to true wake-up events because the wake-up circuit 105 attenuates common-mode signals. Common-mode signal suppression / automatic cancellation can allow for the assembly of less robust structures and other mechanical components for support, and makes the circuitry of device 100 more tolerant to electrical interference. This can relax material requirements and protect the device, allowing the use of lower-cost components, enabling thinner devices, etc.

[0071] Compared to monitoring each piezoelectric sensor individually and analyzing the results by combining each piezoelectric sensor detection result, the wake-up circuit 105 may require less hardware and power.

[0072] The wake-up circuit 105 may be implemented using discrete components or as part of an integrated circuit (IC). Particularly in the case of an IC implementation, the additional hardware required for the wake-up circuit 105 may not be a significant burden.

[0073] The distribution of the piezoelectric sensors between the first subset 103 and the second subset 104 can be realized in a flexible manner using, for example, a pre-settable or programmable selection switch bank, or fixed with dedicated components if no flexibility is required.

[0074] According to an embodiment, the wake-up circuit 105 is further configured to assign a weighting factor to each electrical signal obtained from the plurality of piezoelectric sensors; and generate a sum signal by summing the obtained electrical signals according to the assigned signs and the assigned weighting factors.

[0075] For example, wake-up circuit 105 can assign weighting factors to each piezoelectric sensor before summing. Alternatively, wake-up circuit 105 can sum the signals from first subset 103 to generate a first sum signal, and sum the signals from second subset 104 to generate a second sum signal. Next, wake-up circuit 105 can assign weighting factors to the first sum signal and the second sum signal, and sum the first and second sum signals according to the assigned weighting factors to generate a sum signal. In this way, wake-up circuit 105 can, for example, adjust or adapt to different panels or quantities of piezoelectric sensors, or to changes in the properties of the piezoelectric sensor panel or the piezoelectric sensors themselves.

[0076] Figure 2FIG. 2 is a schematic diagram showing a device 100 providing a wake-up signal to another device 201 according to an embodiment.

[0077] According to an embodiment, the wake-up circuit 105 is configured to provide a wake-up signal to another device 201 electrically coupled to the wake-up circuit 105 .

[0078] Another device 201 may correspond to, for example, an electronic computing device, such as a laptop computer, or certain components of the electronic computing device. Device 100 may be implemented in another device 201. In this case, another device 201 may be referred to as a host device. For example, device 100 may be implemented in a laptop computer, and a wake-up signal may wake the laptop computer from sleep mode, hibernation mode, standby mode, suspend mode, etc. The wake-up signal may correspond to, for example, an appropriate interrupt signal.

[0079] Figure 3 A schematic diagram of the device 100 further comprising a control circuit 301 is shown.

[0080] According to an embodiment, the device 100 further includes a control circuit 301 electrically coupled to the plurality of piezoelectric sensors 102 and the wake-up circuit 105. The wake-up circuit 105 may be further configured to provide at least a wake-up signal to the control circuit 301. The control circuit 301 may be configured to switch to the active mode in response to receiving the wake-up signal while in the standby mode.

[0081] In some embodiments, the control circuit 301 may be electrically coupled to the plurality of piezoelectric sensors 102 through the wake-up circuit 105. In other embodiments, the control circuit 301 may be coupled to the plurality of piezoelectric sensors separately from the wake-up circuit 105.

[0082] Standby mode may refer to any mode in which control circuit 301 does not analyze signals obtained from and / or provide any signals to piezoelectric sensors 102. Standby mode may also be referred to as idle mode, low power mode, sleep mode, etc.

[0083] The control circuit 301 may be further configured to, when in the active mode, obtain an electrical signal from each of the plurality of piezoelectric sensors 102 and locate the object 106 on the touch surface based on the obtained electrical signal.

[0084] Control circuit 301 may be configured to locate object 106 on the touch surface based on the obtained electrical signals and the position of each of piezoelectric sensors 102. For example, control circuit 301 may calculate a weighted average of the electrical signals obtained from piezoelectric sensors 102.

[0085] The control circuit 301 may include at least one processor. The at least one processor may include, for example, one or more of various processing devices, such as a coprocessor, a microprocessor, the control circuit 301, a digital signal processor (DSP), a processing circuit with or without an accompanying DSP, or various other processing devices including integrated circuits (such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microprocessor units (MCUs), hardware accelerators, dedicated computer chips, etc.).

[0086] The control circuit 301 may further include a memory. The memory may be configured to store, for example, a computer program, etc. The memory may include one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, the memory may be implemented as a magnetic storage device (such as a hard disk drive, a floppy disk, a magnetic tape, etc.), an optical magnetic storage device, and 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.).

[0087] When the control circuit 301 is configured to implement a certain function, a certain component and / or several components of the control circuit 301 (for example, at least one processor and / or memory) can be configured to implement this function. Moreover, when the at least one processor is configured to implement a certain function, the function can be implemented using, for example, program code included in the memory.

[0088] The control circuit 301 may further include, for example, a boost converter circuit, a microprocessor, and other components for interacting with the plurality of piezoelectric sensors 102. The control circuit 301 may be further configured to provide tactile feedback, for example, through the plurality of piezoelectric sensors 102. The boost converter may provide the high voltage required to drive the plurality of piezoelectric sensors 102 in the case of tactile feedback.

[0089] In some embodiments, the wake-up circuit 105 may also be implemented as part of the control circuit 301 , for example as part of an IC implementation of the control circuit 301 , or on the same PCB as the control circuit 301 as part of a combined wake-up and control device.

[0090] Figure 4 A plurality of piezoelectric sensors 102 are shown in accordance with an embodiment.

[0091] According to an embodiment, the plurality of piezoelectric sensors 102 are geometrically arranged such that each piezoelectric sensor of the first subset 103 that is not at an edge of the plurality of piezoelectric sensors 102 is adjacent to at least one piezoelectric sensor of the second subset 104 .

[0092] For example, in Figure 4 In the embodiment, each piezoelectric sensor of the first subset 103 that is not at an edge of the plurality of piezoelectric sensors 102 is adjacent to four piezoelectric sensors of the second subset 104 of piezoelectric sensors.

[0093] According to an embodiment, the piezoelectric sensors of the first subset 103 and the piezoelectric sensors of the second subset 104 are geometrically arranged in an alternating pattern. The pattern may alternate in one or more directions.

[0094] For example, in Figure 4 In an exemplary embodiment of the present invention, the piezoelectric sensors of the first subset 103 and the piezoelectric sensors of the second subset 104 alternate in two directions.

[0095] exist Figure 4 In an embodiment, for each piezoelectric sensor in the plurality of piezoelectric sensors 102, each adjacent piezoelectric sensor is in a different subset. Thus, for each piezoelectric sensor in the first subset 103, each adjacent piezoelectric sensor is in the second subset 104, and for each piezoelectric sensor in the second subset 104, each adjacent piezoelectric sensor is in the first subset 103.

[0096] because Figure 4 In the embodiment of the present invention, the plurality of piezoelectric sensors 102 includes the same number of piezoelectric sensors in the first subset 103 and the second subset 104, so the wake-up circuit 105 can effectively suppress common-mode signals. In addition, because the first subset 103 and the second subset 104 are geometrically arranged in an alternating pattern, the wake-up circuit 105 can effectively distinguish between locally applied pressure and common-mode signals.

[0097] It should be understood that although the plurality of piezoelectric sensors 102 may only illustrate a limited number of piezoelectric sensors in the embodiments disclosed herein, the plurality of piezoelectric sensors 102 may include any number of piezoelectric sensors. In addition, the arrangement of the first subset 103 and the second subset 104 can be generalized to any number of piezoelectric sensors by repeating the arrangement in an appropriate manner. For example, Figure 4 The arrangement shown in the embodiment can be generalized to any number of piezoelectric sensors.

[0098] In some embodiments, the plurality of piezoelectric sensors 102 may include an odd number of piezoelectric sensors. Consequently, the number of piezoelectric sensors in the first subset 103 and the second subset 104 may be unequal. In such an embodiment, one piezoelectric sensor may be excluded from the first subset 103 / second subset 104 to ensure that the wake-up circuit 105 eliminates the common-mode signal. Alternatively, the wake-up circuit 105 may be configured to sum the signals from the larger of the two piezoelectric sensors in the first / second subset with half the weight with the remaining piezoelectric sensors.

[0099] Although some embodiments disclosed herein may illustrate multiple piezoelectric sensors 102 in a matrix / array format, these embodiments are merely exemplary. Multiple piezoelectric sensors 102 may be geometrically arranged in any pattern. For example, if multiple piezoelectric sensors 102 are used in a keyboard, each piezoelectric sensor may correspond to a key of the keyboard.

[0100] Figure 5 A plurality of piezoelectric sensors 102 are shown according to another embodiment.

[0101] exist Figure 5 In the embodiment of FIG. 1 , the piezoelectric sensors of the first subset 103 form a square group of four adjacent piezoelectric sensors. Similarly, the piezoelectric sensors of the second subset 104 form a square group of four adjacent piezoelectric sensors. A group of four in the first subset 103 is adjacent to a group of four in the second subset 104, and vice versa.

[0102] Figure 6 A plurality of piezoelectric sensors 102 are shown according to another embodiment.

[0103] exist Figure 6 In one embodiment, in one direction ( Figure 6 In the horizontal direction in the image, the pattern includes two piezoelectric sensors from one subset, followed by one piezoelectric sensor from another subset, and then two piezoelectric sensors from another subset. For example, Figure 6 The top row of includes two piezoelectric sensors from the first subset 103, followed by one piezoelectric sensor from the second subset 104, followed by two piezoelectric sensors from the first subset 103. In the other direction ( Figure 6 The pattern is alternating in the vertical direction. Figure 6 The second row includes two piezoelectric sensors from the second subset 104 , followed by one piezoelectric sensor from the first subset 103 , and then two piezoelectric sensors from the second subset 104 .

[0104] Although in some embodiments disclosed herein, all piezoelectric sensors in the plurality of piezoelectric sensors are assigned to either the first subset or the second subset, this may not be the case in all embodiments. For example, in any embodiment, the plurality of piezoelectric sensors may include a third subset of piezoelectric sensors. When generating the sum signal, signals from the third subset may be ignored. Although the third subset may not be used to generate the sum signal by the wake-up circuit 105, other components may use signals from the third subset to, for example, locate an object on the touch surface.

[0105] Figure 7 FIG. 1 shows a schematic diagram of a wake-up circuit 105 according to an embodiment.

[0106] The wake-up circuit 105 may include a plurality of input resistors 701. Each of the plurality of piezoelectric sensors 102 may be electrically coupled to a corresponding input resistor in the plurality of input resistors 701. The other end of each piezoelectric sensor not coupled to the input resistor may be electrically coupled to a reference voltage V ref .

[0107] The plurality of piezoelectric sensors 102 can be modeled as capacitors. Other electrical / physical properties of the plurality of piezoelectric sensors 102 (such as resistance, inductance, hysteresis, and LC resonance) can also be modeled by adding corresponding electrical components to the models of the plurality of piezoelectric sensors 102. For example, a resistor can be added to model the resistive losses in the piezoelectric sensor. An inductor can be added to model the inductance of the piezoelectric sensor. In many cases, the capacitive behavior of the piezoelectric sensor may be dominant, so modeling the piezoelectric sensor as a single capacitor may be sufficient.

[0108] The wake-up circuit 105 may further include a plurality of attenuation resistors 702. Each input resistor in the plurality of input resistors 701 may be electrically coupled to a corresponding attenuation resistor in the plurality of attenuation resistors 702. The other end of each attenuation resistor may be electrically coupled to a reference voltage V ref The voltage division between the input resistor 701 and the attenuation resistor 702 sets the load of the piezoelectric sensor 102 and the attenuation of the signal obtained from the piezoelectric sensor 102 .

[0109] The wake-up circuit 105 may further include a plurality of weighted resistors 703. Each input resistor in the plurality of input resistors 701 may be electrically coupled to a corresponding weighted resistor in the plurality of weighted resistors 703. The weighted resistors 703 may set the weight of each signal obtained from each piezoelectric sensor.

[0110] Each weighted resistor can be electrically coupled to either the positive input line 710 or the negative input line 711. This can define whether the corresponding piezoelectric sensor belongs to the first subset or the second subset. For example, each piezoelectric sensor electrically coupled to the positive input line 710 can belong to the first subset, while each piezoelectric sensor electrically coupled to the negative input line 711 can belong to the second subset.

[0111] According to an embodiment, the wake-up circuit 105 further includes a plurality of switches 704. Each switch in the plurality of switches 704 can be electrically coupled to a piezoelectric sensor in the plurality of piezoelectric sensors 102 and configured to assign the piezoelectric sensor to the piezoelectric sensors of the first subset 103 or the piezoelectric sensors of the second subset 104. It should be understood that the switch does not need to be directly coupled to the piezoelectric sensor. For example, in Figure 7 In the exemplary embodiment of FIG. 7 , switch 704 is electrically coupled to piezoelectric sensor 102 through resistors 701 , 703 .

[0112] Each weighted resistor can be coupled to a positive / negative input line via a corresponding switch. Each switch can be set between coupling the corresponding weighted resistor to the positive input line and coupling the corresponding weighted resistor to the negative input line. Multiple switches 704 can be implemented using, for example, a pre-settable or programmable selection switch group.

[0113] According to an embodiment, the plurality of switches 704 includes a set of select switches that may be pre-set or programmable.

[0114] The wake-up circuit 105 may further include an amplifier 705, such as an operational amplifier. A positive input line 710 may be coupled to the positive input of the amplifier 705, and a negative input line 711 may be coupled to the negative input of the amplifier 705. Thus, the amplifier 705 may generate a sum signal as an output of the amplifier 705 by summing the electrical signals from the piezoelectric sensors 102. Furthermore, since the piezoelectric sensors 102 may be electrically coupled to the positive and negative inputs of the amplifier 705 in the manner disclosed above, the amplifier 705 may sum the signals of the first subset having positive signs and the signals of the second subset having negative signs.

[0115] When an operational amplifier is used to implement amplifier 705, other electrical components may be required. Figure 7 In the embodiment of the present invention, the wake-up circuit 105 further includes a feedback capacitor C coupled between the output of the operational amplifier 705 and the negative input terminal of the operational amplifier 705. fb and the feedback resistor R fb . C fb and R fb The amplification and bandwidth of the operational amplifier 705 can be set. Figure 7 In the embodiment of the present invention, the wake-up circuit 105 further includes providing a power supply voltage V for the operational amplifier 705.supply The first voltage source 712 provides a reference voltage V ref The second voltage source 713 can be coupled to the positive input terminal of the operational amplifier 705 via a capacitor and a resistor connected in parallel. ref Can be between 0 volts and V supply and the dynamic range of the operational amplifier 705 can be adjusted.

[0116] In some embodiments, V ref In such an embodiment, V ref Can be replaced by ground.

[0117] The wake-up circuit 105 may further include a first comparator 706 and a second comparator 707. The output of the amplifier 705 may be coupled to the negative input of the first comparator 706 and the positive input of the second comparator 707. The wake-up circuit 105 may further include a third voltage source 714 electrically coupled to the positive input of the first comparator 706 and a fourth voltage source 715 electrically coupled to the negative input of the second comparator 707. Therefore, the third input voltage 714 may define a negative threshold voltage, and when the sum signal is less than the negative threshold voltage, the output of the first comparator 706 may be a logically high voltage, such as V supply Similarly, the fourth input voltage 715 may define a positive threshold voltage, and when the sum signal is greater than the positive threshold voltage, the output of the second comparator 707 may be a logically high voltage.

[0118] The third voltage source 714 / the fourth voltage source 715 may be controlled by, for example, a host system. Therefore, the host system may control the sensitivity of the wake-up circuit 105 .

[0119] A first voltage source 712 may be electrically coupled to the first comparator 706 and the second comparator 707 to provide a supply voltage to the comparators 706 , 707 .

[0120] In other embodiments, the wake-up circuit 105 may include only one comparator instead of Figure 7 The two embodiments shown in FIG. 1 and 2 are shown. Using one comparator, the wake-up circuit 105 can be configured to compare the sum signal with one threshold voltage. Alternatively, the wake-up circuit 105 can compare the sum signal with multiple threshold voltages using different threshold voltages during different time windows.

[0121] The wake-up circuit 105 may further include a logic circuit 708 electrically coupled to the outputs of the first comparator 706 and the second comparator 707. The logic circuit 708 may be configured to provide a wake-up signal to the output of the logic circuit 708 in response to the first / second comparator providing a logically high voltage.

[0122] Although some components of device 100 are shown as part of wake-up circuit 105, this is not the only way to implement device 100, and wake-up circuit 105 need not be implemented as a single unit. Instead, wake-up circuit 105 may refer to various components in device 100 that implement the functionality of wake-up circuit 105 disclosed herein.

[0123] Figure 8 FIG. 1 shows a schematic diagram of a wake-up circuit 105 according to another embodiment.

[0124] Figure 8 An embodiment similar to Figure 7 Therefore, unless otherwise indicated, explicitly or implicitly, the Figure 7 Any disclosure of the embodiments of the present invention may also be applied to Figure 8 Example of .

[0125] Figure 8 The wake-up circuit 105 in the embodiment of FIG. 5 may passively implement the summing of the signals obtained from the piezoelectric sensors. Therefore, the wake-up circuit 105 may not include a summing amplifier.

[0126] exist Figure 8 In an embodiment, a positive input line 710 can be coupled to the positive input of the first comparator 706, and a negative input line 711 can be coupled to the negative input of the second comparator 707. The negative input line 711 can be coupled to the negative terminal of a third voltage source 714 and the positive terminal of a fourth voltage source 715. The positive terminal of the third voltage source 714 can be coupled to the negative input of the first comparator 706, and the negative terminal of the fourth voltage source 715 can be coupled to the positive input of the second comparator 707. Therefore, a sum signal is between the positive input line 710 and the negative input line 711. The first comparator 706 can compare the sum signal with a positive threshold voltage defined by the third voltage source 714, and the second comparator 706 can compare the sum signal with a negative threshold voltage defined by the fourth voltage source 715.

[0127] and Figure 7 Similar to the embodiment of Figure 8 In the embodiment of FIG. 1 , a single comparator can also be used to implement the comparison between the sum signal and the threshold. Using one comparator, the wake-up circuit 105 can be configured to compare the sum signal with one threshold voltage. Alternatively, the wake-up circuit 105 can compare the sum signal with multiple threshold voltages using different threshold voltages during different time windows.

[0128] Figure 9 A graph of a sum signal 801 according to an embodiment is shown.

[0129] from Figure 9It can be seen that the sum signal 801 includes various peaks. Some of the peaks may correspond to common mode signals, while some of the peaks may correspond to more localized pressures, due to, for example, a user touching the surface with a finger, among the plurality of piezoelectric sensors 102. Figure 9 In the embodiment shown, the signal applied to one piezoelectric sensor is 10% larger than that applied to the other piezoelectric sensors to account for the fact that all piezoelectric sensors may not be the same.

[0130] exist Figure 9 In the embodiment of FIG. 8 , two thresholds 802 , 803 are also shown. The wake-up circuit 105 may be configured to provide a wake-up signal if the sum signal 801 is greater than the positive threshold 802 or if the sum signal 801 is less than the negative threshold 803 .

[0131] At time t1, a common mode pulse is applied to each of the plurality of piezoelectric sensors 102. Figure 9 It can be seen that the sum signal 801 does not exceed the threshold values ​​802, 803. Therefore, the wake-up circuit 105 does not provide a wake-up signal. At a later time, further common-mode pulses are applied, and the sum signal 801 does not exceed the threshold values ​​802, 803 at these times either.

[0132] At times t2, t3, and t4, more local pressure is applied to the plurality of piezoelectric sensors 102. Consequently, larger peaks can be observed in sum signal 801, and thus, sum signal 801 exceeds thresholds 802 and 803 at these times. At time t2, sum signal 801 is less than negative threshold 803. This may correspond to a situation where the majority of pressure is applied to the piezoelectric sensors belonging to the subset assigned a negative sign. On the other hand, at times t3 and t4, sum signal 801 is greater than positive threshold 802. This may correspond to a situation where the majority of pressure is applied to the piezoelectric sensors belonging to the subset assigned a positive sign.

[0133] According to an embodiment, the device 100 is further configured to adjust at least one preconfigured threshold in response to the sum signal satisfying the threshold.

[0134] In some embodiments, the thresholds 802, 803 may be adjustable. For example, the device 100 may set the initial threshold to a larger value, and after the first wake-up, set the threshold to a lower value to make the device more sensitive.

[0135] Figure 10 A flow chart of a method 900 according to an embodiment is shown.

[0136] According to an embodiment, method 900 includes obtaining an electrical signal 901 from each piezoelectric sensor in a plurality of piezoelectric sensors. The plurality of piezoelectric sensors may be mechanically coupled to a touch surface. Each piezoelectric sensor in the plurality of piezoelectric sensors may be configured to convert a force applied to the piezoelectric sensor by the touch surface into an electrical signal. The plurality of piezoelectric sensors may include at least a first subset of piezoelectric sensors and a second subset of piezoelectric sensors.

[0137] The method 900 may further include assigning a positive sign 902 to the electrical signals obtained from the first subset of piezoelectric sensors and assigning a negative sign 902 to the electrical signals obtained from the second subset of piezoelectric sensors.

[0138] The method 900 may further include generating a sum signal 903 by summing the obtained electrical signals according to the assigned symbols.

[0139] The method 900 may further include comparing 904 the sum signal to a preconfigured condition.

[0140] The method 900 may further include providing a wake-up signal 905 in response to the sum signal satisfying a preconfigured condition.

[0141] If the preconfigured condition is not satisfied, the method 900 may return to operation 901 to obtain a new electrical signal.

[0142] The method 900 may be performed by, for example, the wake-up circuit 105 .

[0143] Figure 11 A schematic diagram of a laptop computer 1000 according to an embodiment is shown.

[0144] The laptop computer 1000 may include a touchpad 1001. The touchpad 1001 may also be referred to as a touchpad. The laptop computer 1000 may further include a keyboard 1002, a screen 1003, and a base 1004. The laptop computer 1000 may further include a keyboard 1002, a screen 1003, and a base 1004. Figure 11 Various other components are shown in the embodiments.

[0145] Although some embodiments may be disclosed herein using a laptop computer as an example, these embodiments are similarly applicable to any other electronic computing device, such as a smartphone, tablet computer, etc.

[0146] Laptop computer 1000 may include device 100. For example, touch surface 101 of device 100 may correspond to the top surface of touchpad 1001. Thus, a user may use touchpad 1001 to operate laptop computer 1000. Laptop computer 1000 may be configured to wake up from a sleep mode or similar mode in response to a wake-up signal provided by wake-up circuit 105. The wake-up signal may correspond to, for example, an interrupt signal or the like that can wake up laptop computer 1000, and wake-up circuit 105 may provide the wake-up signal to a processor of laptop computer 1000. Thus, laptop computer 1000 may wake up in response to a user pressing on touchpad 1001. Because wake-up circuit 105 may eliminate common-mode signals, laptop computer 1000 is less likely to wake up in response to, for example, mechanical or electrical noise sources (e.g., vibrations when laptop computer 1000 is transported).

[0147] Figure 12 A schematic diagram of a laptop computer 1000 according to another embodiment is shown.

[0148] exist Figure 12 In an embodiment, the laptop computer 1000 includes a large touch surface 1101. For example, the large touch surface 1101 can replace the functions of the trackpad 1001 and the keyboard 1002. The touch surface 1101 can include, for example, a display capable of displaying a virtual keyboard to the user. The control circuit 301 can locate touch input on the touch surface 1101 and map the touch input to key presses on the virtual keyboard. Such a virtual keyboard can provide a high degree of flexibility because the keyboard layout can be changed in software. Therefore, there is no need to manufacture physically different versions of the laptop computer 1000 with, for example, ANSI and ISO keyboard layouts. Furthermore, the keyboard can even be changed based on what software is running on the laptop computer 1000. For example, in gaming, the keyboard can be replaced by a touch input scheme suitable for the game of interest.

[0149] Any range or device value given herein may be expanded or changed without losing the effect sought. In addition, any embodiment may be combined with another embodiment unless explicitly not permitted.

[0150] Although the subject matter of the present invention has been described in language specific to structural features and / or acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims, and other equivalent features and acts are intended to fall within the scope of the claims.

[0151] It should be understood that the above-mentioned benefits and advantages may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the problems described or have any or all of the benefits and advantages described. It should also be understood that references to "the" items may refer to one or more of these items.

[0152] The steps of the methods described herein may be performed in any suitable order, or concurrently where appropriate. In addition, individual blocks may be deleted from any method without departing from the spirit and scope of the subject matter described herein. Aspects of any of the above-described embodiments may be combined with aspects of any other described embodiment to form further embodiments without losing the desired effect.

[0153] The term "comprising" is used herein to mean including the identified methods, blocks or elements, but such blocks or elements do not comprise an exclusive list and the method or apparatus may contain additional blocks or elements.

[0154] It should 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 description, examples, and data provide a complete description of the structure and use of the exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity or with reference to one or more individual embodiments, those skilled in the art may make various changes to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. A device (100), comprising: touch surface (101); a plurality of piezoelectric sensors (102) mechanically coupled to the touch surface (101), each piezoelectric sensor of the plurality of piezoelectric sensors (102) being configured to convert a force applied to the piezoelectric sensor via the touch surface (101) into an electrical signal, wherein the plurality of piezoelectric sensors (102) includes at least a first subset (103) of piezoelectric sensors and a second subset (104) of piezoelectric sensors; and a wake-up circuit (105) electrically coupled to the plurality of piezoelectric sensors (102), wherein the wake-up circuit (105) is configured to: obtaining the electrical signal from each of the plurality of piezoelectric sensors (102); assigning a positive sign to the electrical signals obtained from the piezoelectric sensors of the first subset (103), and assigning a negative sign to the electrical signals obtained from the piezoelectric sensors of the second subset (104); generating a sum signal (801) by summing the obtained electrical signals according to the assigned symbols; comparing the sum signal to preconfigured conditions; and A wake-up signal is provided in response to the sum signal satisfying the preconfigured condition.

2. The device (100) according to claim 1, wherein the preconfigured condition comprises at least one preconfigured threshold value (802, 803) for the sum signal (801).

3. The device (100) according to claim 2, wherein the at least one preconfigured threshold (802, 803) comprises a maximum value of the sum signal, a minimum value of the sum signal and / or a maximum value of the absolute value of the sum signal.

4. The device (100) according to claim 2 or 3, wherein the device (100) is further configured to adjust the at least one preconfigured threshold in response to the sum signal satisfying a threshold.

5. The device (100) of claim 1, wherein the wake-up circuit (105) further comprises a plurality of switches (704), wherein each switch of the plurality of switches (704) is electrically coupled to a piezoelectric sensor of the plurality of piezoelectric sensors (102) and is configured to assign the piezoelectric sensor to either the piezoelectric sensors of the first subset (103) or the piezoelectric sensors of the second subset (104).

6. The apparatus (100) of claim 5, wherein the plurality of switches (704) comprises a set of pre-settable or programmable selection switches.

7. The device (100) according to claim 1, wherein the plurality of piezoelectric sensors (102) are geometrically arranged so that each piezoelectric sensor of the first subset (103) of piezoelectric sensors that is not at an edge of the plurality of piezoelectric sensors (102) is adjacent to at least one piezoelectric sensor of the second subset (104) of piezoelectric sensors.

8. The device (100) of claim 1, wherein the piezoelectric sensors of the first subset (103) and the piezoelectric sensors of the second subset (104) are geometrically arranged in an alternating pattern.

9. The device (100) according to claim 1, wherein the wake-up circuit is further configured to: assigning a weighting factor to each electrical signal obtained from the plurality of piezoelectric sensors (102); and The sum signal (801) is generated by summing the obtained electrical signals according to the assigned symbols and the assigned weighting factors.

10. The device (100) of claim 1, further comprising a control circuit (301) electrically coupled to the plurality of piezoelectric sensors (102) and the wake-up circuit (105), wherein the wake-up circuit (105) is further configured to provide at least a wake-up signal to the control circuit (301), and wherein the control circuit (301) is configured to: Switching to the active mode is performed in response to receiving the wake-up signal in the standby mode.

11. The device (100) according to claim 10, wherein the control circuit (301) is further configured to: When in active mode, an electrical signal is obtained from each of the plurality of piezoelectric sensors, and an object (106) on the touch surface (101) is located based on the obtained electrical signal.

12. An electronic computing device (1000) comprising the device (100) of any preceding claim, wherein the electronic computing device (1000) is configured to be awakened from a sleep mode in response to a wake-up signal.

13. A method (900) comprising: Obtaining an electrical signal (901) from each piezoelectric sensor of a plurality of piezoelectric sensors, wherein the plurality of piezoelectric sensors are mechanically coupled to a touch surface, each piezoelectric sensor of the plurality of piezoelectric sensors being configured to convert a force applied to the piezoelectric sensor via the touch surface into an electrical signal, wherein the plurality of piezoelectric sensors includes at least a first subset of piezoelectric sensors and a second subset of piezoelectric sensors; assigning a positive sign to the electrical signals (902) obtained from the first subset of piezoelectric sensors and assigning a negative sign to the electrical signals (902) obtained from the second subset of piezoelectric sensors; generating a sum signal (903) by summing the obtained electrical signals according to the assigned signs; comparing the sum signal to preconfigured conditions (904); and A wake-up signal is provided in response to the sum signal satisfying the preconfigured condition.

14. The method (900) of claim 13, wherein the preconfigured condition comprises at least one preconfigured threshold value for the sum signal.

15. The method (900) of claim 14, wherein The at least one preconfigured threshold value includes a maximum value of the sum signal, a minimum value of the sum signal and / or a maximum value of an absolute value of the sum signal.

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