Apparatus and method for force sensing and electronic device

Abstract

A device (20) and method for force sensing, and an electronic device (1). The device (20) includes a sensor (21) and a filter (22). The sensor (21) is configured to generate a first signal (V). out1 ), the first signal (V out1 The determination is based on the deformation of at least a portion (210) of the sensor (21) and the temperature of at least a portion (210) of the sensor (21). A portion (210) of the sensor (21) is attached to a deformable portion (11) of the electronic device (1). The filter (22) is configured to receive a first signal (V). out1 ), and from the first signal (V out1 Remove changes in ) to obtain the second signal (V) out2 The change is due to the temperature of the portion (210) of the sensor (21). This is related to the first signal (V). out1 Compared to the second signal (V), out2 It is not very sensitive to temperature, so the deformation of the deformable part (11) can be indicated more accurately. When the deformable part (11) deforms, the electronic device (1) can respond accurately.

Description

Technical Field

[0001] This disclosure relates to the field of human-computer interaction, and particularly to apparatus and methods for force sensing and electronic devices. Background Technology

[0002] In recent decades, we have witnessed the rapid development of various electronic devices in people's daily lives. To facilitate use, many input devices have been developed to help users interact with electronic devices. Force-sensitive or strain-sensitive input devices are becoming increasingly popular because they provide a very convenient force-sensing method for interaction between users and various electronic devices. For example, users can input commands to mobile phones or computers by simply touching, pressing, tapping, holding, or stretching the interface with their fingers or a stylus.

[0003] User interfaces equipped with force-sensitive or strain-sensitive input devices are typically located in deformable parts of electronic devices, such as virtual keyboards or buttons on flexible displays, elastic portions of plastic casings, or thinned sections of metal casings. Force-sensitive or strain-sensitive input devices detect deformation of the user interface, that is, they detect the force or strain caused by the operation, enabling the electronic device to recognize such operations. Figure 1 This is a schematic diagram of the structure of a force-sensitive or strain-sensitive input device in conventional electronic equipment. For example... Figure 1 As shown, the force-sensitive or strain-sensitive input device includes a force sensor 3 located at the operating interface 2 of the electronic device 1, and an analog-to-digital comparator (ADC) 4. The force sensor 3 is configured to generate an electrical signal and transmit the signal to the ADC 4. The ADC 4 is configured to compare the signal with a threshold signal defined by a preset threshold signal and output a signal indicating the comparison result. The threshold signal represents the degree of deformation to be identified by the electronic device. The result is then transmitted to a controller (or processor) 5, which determines whether the operating area is deformed based on the state of the signal.

[0004] Typically, force sensors use their electrical properties to reflect force or strain at the operating area, and these properties are sensitive to temperature. For example, the electrical properties can be related to resistance, which is strongly dependent on temperature based on the temperature coefficient of resistance of the force sensor material. Similarly, electrical properties related to inductance also depend on temperature.

[0005] The rapid development of electronic devices has further complicated the temperature environment within them. On the one hand, the miniaturization of electronic devices presents significant challenges to heat dissipation, and the internal temperature changes drastically when switching between different operating modes, such as acceleration, energy-saving, and sleep modes. On the other hand, considering various application scenarios, the ambient temperature of electronic devices is quite unstable. For example, wearable electronic devices exchange heat with human skin, so the shell temperature is higher when the user is exercising than when the user is resting. Furthermore, outdoor electronic devices are heated in sunny weather and cooled in cloudy or rainy weather. Since the electrical characteristics of force sensors, such as resistance and inductance, are temperature-dependent, the output signal of the force sensor will drift relative to its theoretical value when the temperature is unstable. Even when the operating interface is not deformed, each time the drifted output signal reaches a threshold defined by a threshold signal, the comparison result at the ADC will indicate that the operating interface has been deformed. Therefore, the controller or processor issues instructions based on error detection, and the electronic device malfunctions. Summary of the Invention

[0006] To address the aforementioned technical problems, the following technical solutions are provided based on the embodiments of this disclosure.

[0007] In a first aspect, embodiments of the present disclosure provide an apparatus for force sensing. The apparatus is located in an electronic device, and the electronic device includes a deformable portion. The apparatus includes a sensor and a filter. The sensor is configured to generate a first signal, wherein the first signal is determined based on the deformation of at least a portion of the sensor and the temperature of at least a portion of the sensor, and a portion of the sensor is attached to the deformable portion. The filter is configured to receive the first signal and remove variations from the first signal to obtain a second signal, wherein the variations are due to the temperature of a portion of the sensor.

[0008] In one embodiment, the apparatus further includes at least one comparator. The comparator in the at least one comparator is configured to: receive a second signal; determine whether the deformable portion is deformed based on the second signal and a threshold signal; and generate a third signal, wherein the third signal is activated in response to determining that the deformable portion is deformed.

[0009] In one embodiment, the device further includes an analog-to-digital converter (ADC). The filter is an analog filter, and the ADC is configured to convert the second signal into a digital signal before the second signal is input to the comparator. Alternatively, the filter is a digital filter, and the ADC is configured to convert the first signal into a digital signal before the first signal is input to the comparator.

[0010] In one embodiment, the device further includes a flexible layer attached to the deformable portion. A portion of the sensor is attached to the deformable portion via at least a portion of the flexible layer.

[0011] In one implementation, a portion of the sensor is a strain-sensitive element.

[0012] In one embodiment, the sensor includes a Wheatstone bridge circuit and an amplifier circuit. The arms of the Wheatstone bridge circuit include strain-sensitive elements. The amplifier circuit includes an operational amplifier. The inverting and non-inverting input terminals of the operational amplifier are coupled to the two output terminals of the Wheatstone bridge circuit, respectively. The output terminal of the operational amplifier is coupled to the input terminal of a filter. A first signal includes a first signal output from the output terminal of the operational amplifier.

[0013] In one implementation, the strain-sensitive element is a strain gauge.

[0014] In one embodiment, the strain-sensitive element is a metal foil pattern of a strain gauge, and the flexible layer is a backing layer on which the metal foil pattern is printed.

[0015] In one implementation, a portion of the sensor is embedded within a flexible layer.

[0016] In one embodiment, the flexible layer includes one or both of the following: a layer made of a thermally insulating material and a thermally diffusing layer. In the thermally diffusing layer, the thermal conductivity along the thickness of the thermally diffusing layer is less than the thermal conductivity in a plane perpendicular to the thickness of the thermally diffusing layer.

[0017] In one embodiment, the thermal conductivity along the thickness of the heat diffusion layer is one-tenth of the thermal conductivity in a plane perpendicular to the thickness of the heat diffusion layer.

[0018] In one embodiment, the thermal conductivity of the thermal insulation material along the thickness of the flexible layer is equal to or less than 0.1 W / mK.

[0019] In one embodiment, the thermal insulation material includes one or more graphite sheets, rock wool, or a paste.

[0020] In one embodiment, a portion of the flexible layer has a thickness between 25 μm and 500 μm.

[0021] In one embodiment, the filter includes at least one of a high-pass filter, a band-pass filter, or a band-stop filter.

[0022] In one implementation, the analog-to-digital converter is integrated with at least one of a sensor, filter, or comparator in the circuit.

[0023] In one implementation, the threshold signal includes a threshold signal for compression. The comparator is also configured to determine whether the deformable portion is compressed based on the second signal and the threshold signal for compression. A third signal is activated in response to compression of the deformable portion.

[0024] In one embodiment, the threshold signal includes a threshold signal for tensioning. The comparator is also configured to determine whether the deformable portion is stretched based on the second signal and the threshold signal for tensioning. A third signal is activated in response to the deformable portion being stretched.

[0025] In a second aspect, an electronic device is provided according to embodiments of the present disclosure. The electronic device includes any of the above-described devices, a deformable portion, and a hardware module. The hardware module is configured to receive a second signal, wherein the state of the hardware module changes in response to a change in the state of the second signal. Alternatively, the hardware module is configured to receive a third signal, wherein the state of the hardware module changes in response to the third signal being in an active state.

[0026] In one implementation, the hardware module includes at least one of the following: a processor, a controller, a display, a speaker, a switch, or an indicator light.

[0027] In one embodiment, the electronic device includes at least one of the following: a mobile phone, a watch, glasses, a head-mounted display device, earphones, a keyboard, or a tablet computer.

[0028] In a third aspect, embodiments of the present disclosure provide a method for force sensing. The method is applied to an electronic device, and the method includes: generating a first signal by a sensor, wherein the first signal is determined based on deformation of at least a portion of the sensor and temperature of at least a portion of the sensor, and a portion of the sensor is attached to a deformable portion of the electronic device; receiving the first signal through a filter; and removing a change from the first signal through the filter to obtain a second signal, wherein the change is due to the temperature of a portion of the sensor.

[0029] In one embodiment, the method further includes: receiving a second signal by a comparator in at least one comparator; determining by the comparator whether the deformable portion is deformed based on the second signal and a threshold signal; and generating a third signal by the comparator, wherein the third signal is activated in response to determining that the deformable portion is deformed.

[0030] An apparatus and method for force sensing, as well as an electronic device, are provided. The apparatus includes a sensor and a filter. The sensor is configured to generate a first signal determined based on the deformation of at least a portion of the sensor and the temperature of at least a portion of the sensor. A portion of the sensor is attached to a deformable portion of the electronic device. The filter is configured to receive the first signal and remove variations from the first signal to obtain a second signal, wherein the variations are due to the temperature of the portion of the sensor. The second signal is less sensitive to temperature than the first signal, and therefore can more accurately indicate the deformation of the deformable portion. The electronic device can respond accurately when the deformable portion deforms. Attached Figure Description

[0031] The accompanying drawings, which briefly describe embodiments or conventional techniques intended for use with this disclosure, are provided below. Those skilled in the art can derive other drawings based on the provided drawings without any inventive effort.

[0032] Figure 1 This is a schematic diagram of the structure of a force-sensitive or strain-sensitive input device in conventional electronic equipment.

[0033] Figure 2 This is a schematic diagram of strain gauges and their operating states in conventional technology;

[0034] Figure 3 This is a schematic diagram of a force-sensitive or strain-sensitive input device based on a strain gauge and a Wheatstone bridge.

[0035] Figure 4 It is an operating algorithm for a comparator that operates based on strain gauges and Wheatstone bridges;

[0036] Figure 5 It is a schematic diagram showing the change in the signal of the force applied to the deformable part;

[0037] Figure 6 It is a schematic diagram showing the changes in force and temperature signals in the deformable part;

[0038] Figure 7 This is a schematic diagram of the structure of an electronic device employing a force sensing device according to an embodiment of the present disclosure;

[0039] Figure 8 This is a schematic diagram of the structure of an electronic device employing a force sensing device according to another embodiment of the present disclosure;

[0040] Figure 9 This is the operation algorithm of the comparator according to the embodiments of this disclosure;

[0041] Figure 10a and Figure 10bThis is a structural schematic diagram of a force sensing device according to other embodiments of the present disclosure;

[0042] Figure 11 This is a structural schematic diagram of a force sensing device according to an embodiment of the present disclosure;

[0043] Figures 12a to 12c This is a structural schematic diagram of a cross-sectional view of a portion of a sensor attached to a deformable portion according to an embodiment of the present disclosure;

[0044] Figure 13a and Figure 13b This is a structural schematic diagram of a strain gauge attached to a deformable portion according to an embodiment of the present disclosure.

[0045] Figure 14 This is a schematic diagram of heat conduction through a flexible layer according to an embodiment of the present disclosure;

[0046] Figure 15 This is a schematic diagram illustrating the temperature change over time when the sensor is attached to the deformable portion with or without a flexible layer, according to embodiments of this disclosure; and

[0047] Figure 16 This is a schematic diagram illustrating the changes in force (or strain) and temperature signals of a deformable portion according to embodiments of this disclosure. Detailed Implementation

[0048] The technical solutions of the embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the described embodiments are only some embodiments of this disclosure, and not all embodiments. Any other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without any creative effort fall within the protection scope of this disclosure.

[0049] As described in the background section, conventional force-sensitive or strain-sensitive input devices are affected by the drift output signal of the force sensor, resulting in inaccurate results regarding whether the operating interface is deformed. Details of this technical problem are described below, using a strain gauge-based force sensor as an example. Those skilled in the art will understand that, with necessary modifications, this technical problem can also be applied to other types of force sensors, provided the force sensor is temperature-sensitive.

[0050] Reference Figure 2 This is a schematic diagram of a strain gauge and its operating state in conventional technology. The strain gauge is configured to measure strain on an object. Common types of strain gauges may include an insulating flexible backing supporting a pattern of metal foil, such as... Figure 2As shown. The metal foil pattern consists of a winding pattern whose thickness is sensitive to strain, and two terminals at both ends of the winding pattern. The strain gauge can be attached to the object using a suitable adhesive. When the object deforms, the foil pattern deforms, and the resistance of the foil pattern changes accordingly. Typically, compression of the object thickens the metal foil pattern, thus reducing the resistance of the strain gauge. Conversely, tension of the object thins the metal foil pattern, thus increasing the resistance of the strain gauge. In practice, the two terminals can be connected to the arms of a Wheatstone bridge, a common method for measuring resistance.

[0051] A typical Wheatstone bridge consists of an upper arm and a lower arm, each of which includes two resistors connected to a common node. Three of the four resistors are fixed resistors, while the third is a variable (or the resistor to be measured) resistor. The two ends of the upper arm are connected to the two ends of the lower arm, and the two connection nodes serve as the two output terminals of the Wheatstone bridge. The two common nodes of the upper and lower arms serve as the power supply terminals of the Wheatstone bridge. Therefore, given the resistances of the three resistors and the voltage between the two power supply terminals, the resistance to be measured can be derived from the voltage between the two output terminals. Other variations of the Wheatstone bridge circuit not described in detail herein can be readily obtained by those skilled in the art.

[0052] Then refer to Figure 3 This is a schematic diagram of a force-sensitive or strain-sensitive input device based on a strain gauge and a Wheatstone bridge. Figure 3 The structure shown is based on Figure 1 The illustrated structure is based on a force sensor 3 comprising a Wheatstone bridge circuit 30 and an operational amplifier 32. The lower arm of the Wheatstone bridge circuit 30 includes a strain gauge 31, which functions as a variable (or measured) resistor, and the strain gauge 31 is mounted on a deformable portion (e.g., an operating interface) 2 of the electronic device 1. The two output terminals of the Wheatstone bridge circuit 30 are coupled to the inverting and non-inverting input terminals of the operational amplifier 32, respectively. The output terminal of the operational amplifier 32 is coupled to the input terminal of the analog-to-digital converter (ADC) 4. Figure 3 In the diagram, the signals at the inverting input terminal, the non-inverting input terminal, and the output terminal of operational amplifier 32 are represented as V, respectively. IN1 V IN2 and V OUT There is a V. OUT =A*(V IN1 -V IN2 ), where A is the gain of operational amplifier 32.

[0053] Based on such Figure 3 In the structure shown, the ADC is provided with an algorithm for determining whether the deformable part 2 is deformable. (Refer to...) Figure 4It is an ADC operating algorithm based on strain gauges and a Wheatstone bridge. Figure 4 The operation algorithm includes steps S1 to S4.

[0054] In step S1, the output signal V OUT It is converted into a digital signal.

[0055] Operational amplifiers simply amplify the input signal V IN1 With V IN2 The difference between them is used to generate the output signal V. OUT Therefore, the output signal V OUT It is an analog signal. As described in the background section, the ADC is configured to output signal V OUT With threshold signal V TH Comparison is required. Typically, the signal should be digital for comparison; therefore, the ADC needs to compare the output signal V. OUT Perform analog-to-digital conversion. Threshold signal V TH It can be preset to a digital level in the ADC, or it can be a digital signal input to the ADC. Alternatively, the threshold signal V TH This can be an analog signal input to the ADC. In this case, the ADC is also configured to convert the threshold signal V... TH It is converted into a digital signal.

[0056] In step S2, the output signal V is determined. OUT Is the signal V below (or above) the threshold? TH If the result is affirmative, the algorithm proceeds to step S3; and if the result is negative, the algorithm proceeds to step S4.

[0057] For ease of explanation, it is assumed that the strain gauge 31 is in a zero-strain state, and the two input signals V of the operational amplifier 32 are... IN1 and V IN2 They are in equilibrium, meaning their values ​​are the same. The zero-strain state means that strain gauge 31 is neither under tension nor compression. Those skilled in the art will understand the various ways to achieve this assumption. For example, in... Figure 3 In the upper arm, the ratio of the resistance of the left resistor to the resistance of strain gauge 31 under zero strain conditions is equal to the ratio of the resistance of the right resistor in the upper arm to the resistance of the right resistor in the lower arm. Under zero strain conditions, the output signal V of operational amplifier 32... OUT Represented as reference signal V REF In the above situation, V REF =0. When strain gauge 31 is subjected to tension or compression, V OUT >0 or V OUTThe value is <0, depending on the material of the strain gauge 31 and the connection between the Wheatstone bridge circuit 30 and the operational amplifier 32. It is understandable that when the resistors in the Wheatstone bridge structure are configured otherwise, the reference signal V... REF It can be another value.

[0058] Reference Figure 5 This is a schematic diagram illustrating the change in force (or strain) signal of a deformable part. Taking the deformation of deformable part 2 caused by an external force and a Gaussian time distribution as an example, when deformable part 2 is stretched (e.g., due to a user-applied poke or pressure causing a flat surface to expand), strain gauge 31 is subjected to tension, thus increasing its resistance, while the resistances of the three resistors in the Wheatstone bridge circuit remain constant. Assuming signal V... CC The voltage is higher than the signal V SS The voltage, then the inverted input signal V IN1 Increase, while the in-phase input signal V IN2 The output signal V remains unchanged. OUT Reduce. To distinguish between effective stretching and unintentional stretching or noise signals, the threshold signal V is... TH It can be set below the reference signal V REF The level (i.e., in the above case, V) TH <0).

[0059] In step S3, the ADC indicates that the deformable part is deformed.

[0060] In step S4, the ADC indicates that the deformable part is not deformed.

[0061] Further reference Figure 5 In the output signal V OUT Signal V below the threshold TH In this case, it means that the deformation (tension or stretching) is strong enough to be recognized as a valid input signal (e.g., a user pressing a virtual button to turn on an electronic device), and the output signal of ADC 4 will go high to notify the controller (or processor) 5 to perform the operation corresponding to the deformation (e.g., turning on the electronic device). At the output signal V OUT Signal V that is higher than or equal to the threshold TH In this case, it means that the deformation (tension or stretching) is not strong enough to be recognized as a valid input signal (e.g., a user accidentally touches a virtual button), and the output signal of ADC 4 will go low and not notify the controller (or processor) 5 to perform the corresponding operation. In other words, ADC 4 can indicate whether the deformed part is deformed by the state of the output signal of ADC 4.

[0062] The accuracy of the above algorithm depends on the ability of the strain gauge 31 to accurately reflect the force (or strain) information at the deformable part. Given that the force sensor 3 is sensitive to temperature, this accuracy will deteriorate.

[0063] Generally, the temperature coefficient of resistance of metallic materials is greater than zero. Since strain gauge 31 is attached to deformable portion 2, the resistance of the metal foil pattern in strain gauge 31 is positively correlated with the temperature in deformable portion 2. That is, when the temperature of deformable portion 2 increases, the resistance is expected to increase, and when the temperature of deformable portion 2 decreases, the resistance is expected to decrease.

[0064] Reference Figure 6 It is a schematic diagram showing the changes in force (or strain) and temperature signals in a deformable part. Figure 6 The temperature of the deformable portion 2 undergoes a gradual decrease as an example. For instance, when an electronic device switches from acceleration mode to power-saving mode, the temperature of the deformable portion near the central processing unit (CPU) may decrease, or when a wearable device is detached from the human body, the temperature of the deformable portion attached to the metal casing may decrease. Clearly, the temperature of strain gauge 31 will follow a similar change in the temperature of the deformable portion 2, and the resistance of strain gauge 31 will decrease accordingly. In this case, even if no compression (or tension) is applied to the deformable portion 2, the inverted input signal V... IN1 It also gradually decreases, thus the actual reference signal V REF It will drift to a value higher than the expected reference signal V. REF The level.

[0065] At approximately t0, when the temperature has already decreased, it will be like... Figure 5 The same external force that causes deformation is applied to the deformable part and used as the input operation. This force results in a force similar to... Figure 5 The valley of the valley. That is, in the reference signal V. REF With threshold signal V TH If the difference between them remains at the expected position, the output signal V OUT It should be from the reference signal V REF Drops below the threshold signal V TH The defined threshold level. However, due to the reference signal V REF The actual (drifted) reference signal V has drifted to a level higher than the expected position. REF With threshold signal V TH The difference between them increases, and even the bottom of the valley may not reach the threshold signal V. TH A defined threshold. Therefore, the comparison result of ADC 4 indicates the output signal V. OUT Maintain a signal above the threshold V THTherefore, ADC 4 will not activate its output signal (e.g., go high), and the controller (or processor) 5 will not be notified of the deformation of the deformable part. Consequently, the electronic device may "miss" an input operation around time t0 and fail to respond.

[0066] According to embodiments of this disclosure, a novel structure for a force sensing device is proposed, in which a filter is incorporated to remove temperature-induced variations from the signal output by the sensor, such that the signal is determined solely or primarily based on the deformation of the deformable portion.

[0067] Reference Figure 7 This is a schematic diagram of an electronic device employing a force sensing device according to an embodiment of the present disclosure. The force sensing device 20 is applied in the electronic device 10, and the electronic device 10 includes a deformable portion 11. The electronic device 10 may include a mobile phone, watch, glasses, head-mounted display device, earphones, keyboard, tablet computer, etc. The deformable portion may be a flexible display of a mobile phone, a wristband of a watch, an elastic frame of glasses or a head-mounted display device, a metal or plastic shell of an earphone, a membrane of a keyboard, elastic main keys of a tablet computer, etc. It should be understood that the electronic device 10 and the deformable portion 11 are not limited to the above-described cases, and for the sake of brevity, specific examples are not listed herein.

[0068] Device 20 includes sensor 21 and filter 22. For ease of explanation, Figure 7 The diagram shows only one sensor 21 and one filter 22. Unless otherwise described, those skilled in the art will understand that the following description of sensor 21 and filter 22, with necessary modifications, can also be applied to cases with multiple sensors 21 or multiple filters 22.

[0069] Sensor 21 is configured to generate a first signal V OUT1 First signal V OUT1 The determination is based on the deformation and temperature of at least a portion 210 of sensor 21. This is determined solely by the first signal V generated by sensor 21. OUT1 Sensitive to both deformation and temperature of a portion 210 of sensor 21, sensor 21 can be implemented in various forms. In this embodiment, a portion 210 of sensor 21 is attached to deformable portion 11. See also... Figure 12aThis is a schematic cross-sectional view of a portion of a sensor attached to a deformable portion according to an embodiment of the present disclosure. When the deformable portion 11 deforms, a portion 210 of the sensor 21 deforms together with the deformable portion 11, or a portion of the sensor 21 undergoes at least strain due to the deformation of the deformable portion 11. When the temperature of the deformable portion 11 changes (e.g., the deformable portion is heated or cooled), the temperature of the portion 210 of the sensor 21 also changes due to heat conduction from the deformable portion 11. That is, the first signal V... OUT1 It also depends on the deformation of the deformable part 11 and the temperature of the deformable part 11.

[0070] In one embodiment, sensor 21 may include a Wheatstone bridge circuit and an amplifier circuit. Arms of the Wheatstone bridge circuit include strain-sensitive elements that serve as part 210 of sensor 21. The amplifier circuit includes an operational amplifier. The inverting and non-inverting input terminals of the operational amplifier are respectively coupled to the two output terminals of the Wheatstone bridge circuit, and the output terminal of the operational amplifier is coupled to the input terminal of at least one comparator. First signal V OUT1 This includes the signal output from the output terminal of the operational amplifier.

[0071] In this embodiment, the strain-sensitive element is primarily configured to detect the deformation of the deformable portion 11. Detection is achieved through the electrical characteristics of the strain-sensitive element, which are affected by the deformation of the deformable portion 11. For example, the electrical characteristics are related to the resistance, inductance, or capacitance of the strain-sensitive element. A Wheatstone bridge circuit is an effective method for accurately measuring the electrical characteristics of a strain-sensitive element, especially when the electrical characteristics are related to inductance or capacitance. It should be understood that, depending on the actual electrical characteristics, the Wheatstone bridge circuit can be replaced by another suitable circuit.

[0072] In one embodiment, the electrical characteristics of the strain-sensitive element are related to resistance or inductance. For example, the strain-sensitive element is a strain gauge. That is, a portion 210 of sensor 21 is a strain gauge. As another example, the strain-sensitive element includes two contacts separated by a gap, and the contact resistance (or inductance) between the two contacts changes monotonically with the width of the gap.

[0073] The amplifier circuit is primarily configured to amplify the measurement signal output from the Wheatstone bridge circuit in order to acquire the first signal V. OUT1 In one implementation, amplification is achieved via an operational amplifier. The operational amplifier can be connected in various ways, such as in open-loop mode, closed-loop mode, negative feedback mode, low-pass filter mode, or integrator circuit mode. This disclosure is not limited thereto, and other connection methods may be available, as long as they amplify the measurement signal output from the Wheatstone bridge circuit.

[0074] Typically, the electrical characteristics of a strain-sensitive element are sensitive to the temperature of sensor 21. Therefore, even if the measurement of the Wheatstone bridge circuit (or other measurement circuit) and the amplification of the amplifier circuit are accurate, the first signal V... OUT1 It may also fail to accurately reflect deformation due to its temperature dependence.

[0075] Filter 22 is configured to receive the first signal V OUT1 Remove the temperature changes caused by a portion 210 of sensor 21 to obtain the second signal V. OUT2 Typically, the temperature of a portion 210 of sensor 21 varies due to thermal conduction from the deformable portion 11 to which it is attached. The nature of thermal conduction limits the heat flux intensity to always being negatively proportional to the temperature gradient. Therefore, heat can only gradually penetrate new areas, meaning that the temperature of portion 210 takes some time to catch up with the temperature of the deformable portion 11. Thus, the temperature change of a portion 210 of sensor 21 typically follows a gentle slope. In contrast, deformation to be detected by electronic device 10 is caused by changes in the mechanical state of electronic device 10, such as by a portion of electronic device 10 being pressed, gripped, or folded. Such mechanical changes occur briefly and are generally not delayed (neglecting buffering) when transferred to the deformable portion 11 and the attached portion 210. Therefore, for a portion 210 of sensor 21, deformation is more abrupt than temperature changes. Both of these changes are detected by the first signal V. OUT1 The change is reflected in the first signal V OUT1 The signals are separated from each other in the frequency spectrum. The change caused by the deformation of a portion 210 of sensor 21 (hereinafter referred to as the first change) is located in the higher frequency region, while the change caused by the temperature of a portion 210 of sensor 21 (hereinafter referred to as the second change) is located in the lower frequency region. Therefore, filter 22 can filter the first signal V by applying an appropriate frequency threshold. OUT1 The second change is removed from the signal. This removal can be achieved in various ways. For example, the frequency region containing the second change can be zeroed out. As a result of the removal, information about the first change is retained in the second signal V. OUT2 In the middle, the information of the second change does not exist in the second signal V. OUT2 middle.

[0076] Filter 22 can be implemented in various forms. In one embodiment, filter 22 may include a high-pass filter. That is, frequency components below a frequency threshold can be zeroed out, so that the second variation can be removed from the first signal. In another embodiment, filter 22 may include a band-pass filter. That is, frequency components below a lower frequency threshold and above a higher frequency threshold can be zeroed out, so that both the second variation and some high-frequency noise can be removed from the first signal. Alternatively, filter 22 may include a band-stop filter. That is, the second variation located between a lower frequency threshold and a higher frequency threshold can be zeroed out.

[0077] In one implementation, the second signal V OUT2 The data can be transmitted to the hardware module 12 of the electronic device 10. The hardware module 12 is configured to receive the second signal V. OUT2 And the state of hardware module 12 responds to the second signal V OUT1 The state changes accordingly. For example, hardware module 12 can be a switching transistor, where the second signal V changes. OUT2 When the value rises above the threshold, the switching transistor turns on, and when the second signal V... OUT2 The switching transistor turns off when the signal drops below a threshold. For example, hardware module 12 could be an analog-to-digital (AD) converter, where the second signal V... OUT2 When the signal rises above the threshold, the AD converter outputs a high level, and when the second signal V... OUT2 When the voltage drops below the threshold, the AD converter outputs a low level.

[0078] In the force sensing device 20 according to the above embodiment of the present disclosure, the sensor 21 generates a first signal V. OUT1 First signal V OUT1 The filter 22 determines the signal based on the deformation and temperature of a portion 210 of sensor 21. OUT1 In order to remove the changes caused by the temperature of a portion 210 of sensor 21 in order to acquire the second signal V OUT2 Compared to the first signal, the second signal V OUT2 It depends more on the deformation of a portion 210 of sensor 21, and the second signal V OUT2 The temperature of a portion 210 of sensor 21 is not very sensitive. Therefore, the second signal V OUT2 The state can accurately indicate the deformation of the deformable part 11. Accordingly, when the deformation of the deformable part 11 is used as an input operation, the electronic device 10 of the application device 20 can make an accurate response.

[0079] The following provides some implementation methods to better understand the technical solutions of this disclosure. However, this disclosure is not limited to these implementation methods.

[0080] Reference Figure 8 This is a schematic structural diagram of an electronic device employing a force sensing apparatus according to another embodiment of the present disclosure. In such... Figure 7 Based on the structure shown, device 20 further includes a comparator 23. Comparator 23 is configured to receive the second signal V. OUT2 It should be understood that the second signal V can be achieved by coupling the output terminal of filter 22 to the input terminal of comparator 23. OUT2 The comparator 23 can be an AD comparator, or it can include an AD converter and a processor for comparing digital signals. In some embodiments, multiple comparators 23 can be configured to receive the second signal V. OUT2 The discussion below focuses primarily on one comparator 23, and it should be understood that such discussion can also be applied to each of the multiple comparators 23.

[0081] Comparator 23 is also configured to be based on the second signal V OUT2 and threshold signal V TH ( Figure 8 (Not shown) determines whether the deformable portion 11 is deformed. Since a portion 210 of the sensor 21 is attached to the deformable portion 11, the deformation of the deformable portion 11 can be reflected by the deformation of the portion 210 of the sensor 21. Therefore, the second signal V includes information about the deformation of the portion 210 of the sensor 21. OUT2 It can be used as a deterministic basis. Threshold signal V TH This corresponds to the degree of deformation (of the deformable portion 11 or correspondingly a portion 210 of the sensor 21) to be recognized by the electronic device 10. Threshold signal V TH The signal can be preset to a digital level in comparator 23, or it can be a digital signal input to comparator 23. Alternatively, the threshold signal V... TH It can be an analog signal input to comparator 23, and comparator 23 applies a threshold signal V. TH Previously, the threshold signal V TH The signal is converted into a digital signal. Comparator 23 can determine whether the deformable part 11 deforms in various ways. In one embodiment, this is done by comparing the second signal V. OUT2 and threshold signal V TH The threshold signal V of the different comparators 23 is determined by the level of the comparator. TH They can be the same or different.

[0082] Comparator 23 is also configured to generate a third signal V OUT3 The third signal V OUT3 It is activated in response to the determination of deformation of deformable part 11. Third signal V OUT3 The specific activation state is based on the actual situation and is not limited in this paper, as long as the activation state is within the third signal V. OUT3 The state is distinguishable and serves as an indicator for the deformation of the deformable part 11. For example, the active state can be high or "1", or it can be low or "0".

[0083] The operation algorithm of comparator 23 can be compared with that of comparator 23. Figure 4 The operation algorithms shown are similar. Figure 9 This is the operation algorithm of comparator 23 according to an embodiment of this disclosure. Figure 9 In this process, the operation algorithm of comparator 23 may include steps S11 to S14.

[0084] In step S11, the second signal V OUT2 It is converted into a digital signal. It should be understood that in the second signal V... OUT2 If the signal is digital, step S11 can be omitted.

[0085] Second signal V OUT2 The output from filter 22 can be analog. That is, filter 22 can be an analog filter. Generally, digital signals are easier to compare than analog signals. Therefore, based on the second signal V... OUT2 and threshold signal V TH Before determining the second signal V, it is necessary to analyze it. OUT2 An AD conversion is performed. In this case, device 20 may also include an AD converter 24. (See reference...) Figure 10a This is a schematic diagram of a force sensing device according to another embodiment of the present disclosure. The AD converter 24 can be coupled between the filter 22 and the comparator 23, and is configured to convert the second signal V... OUT2 The second signal V is input to comparator 23 before being fed into it. OUT2 It is converted into a digital signal.

[0086] It should be understood that, in the above scenario, the AD converter can be integrated with filter 22 or comparator in the circuit. That is, filter 22 can first filter the first signal V. OUT1 To obtain the simulated second signal V OUT2 Then, the simulated second signal V OUT2 To perform an A / D conversion, or the comparator can first compare the analog second signal V... OUT2 Perform an A / D conversion, and then base the result on the second signal V. OUT2 Sure.

[0087] Alternate location, second signal V OUT2 The output from filter 22 can be digital. That is, filter 22 can be a digital filter. A digital filter can be integrated with a comparator in the circuit. Due to the first signal V... OUT1 Typically, it's an analog signal output from sensor 21, therefore, it's necessary to filter the first signal V. OUT1 Previously, regarding the first signal V OUT1 Perform AD conversion. (Refer to...) Figure 10b This is a schematic diagram of a force sensing device according to another embodiment of the present disclosure. An AD converter 24 can be coupled between the sensor 21 and the filter 24, and is configured to convert the first signal V... OUT1 The first signal V is input to filter 24 before being passed to filter 24. OUT1 It is converted into a digital signal.

[0088] It should be understood that, in the above scenario, the AD converter can be integrated with sensor 21 or filter 22 in the circuit. That is, sensor 21 can convert the analog first signal V. OUT1 And directly output a digital signal, or filter 22 can first process the analog first signal V. OUT1 Perform an A / D conversion, and then process the first signal V after the conversion. OUT1 Perform filtering.

[0089] In step S12, the second signal V is determined. OUT2 Signal V below (or above) the threshold TH If the result is affirmative, the algorithm proceeds to step S13; if the result is negative, the algorithm proceeds to step S14.

[0090] Determine the signal V below the threshold TH The signal V is still above the threshold. TH Depending on the specific circumstances, deformation will result in a second signal V. OUT2 When the threshold signal V increases, TH It is typically set to be greater than the second signal V in the reference state. OUT2 A high level, and determine whether it is higher than the threshold signal V. TH The deformation will result in a second signal V. OUT2 In the case of a decrease, the threshold signal V TH It is typically set to be greater than the second signal V in the reference state. OUT2 A low level, and determine whether it is below the threshold signal V. TH The reference state refers to the state in which the deformable part 11 is not affected by deformation or a preset reference deformation degree. In the following text, the second signal V in the reference state... OUT2The reference signal V REF2 Accordingly, the first signal V in the reference state OUT1 The reference signal V REF1 .

[0091] It is worth noting that in the second signal V OUT2 Equal to the threshold signal V TH At that time, comparator 23 can determine whether the deformable part 11 is deformed or not, based on actual requirements.

[0092] In step S13, the third signal V in the active state is output. OUT3 The activation status indicates that deformable part 11 can deform.

[0093] In step S14, the third signal V in the inactive state is output. OUT3 The inactive state is the third signal V. OUT3 One or more states other than the active state, and indicating that the deformable part 11 is not deformed.

[0094] In one implementation, the third signal V OUT3 The hardware module 12 can be transmitted to the electronic device 10. The hardware module 12 is configured to receive a third signal V. OUT3 Furthermore, the state of hardware module 12 changes in response to a third signal that is in an active state.

[0095] It should be understood that the above operation algorithm is only an example, and comparator 23 can apply another operation algorithm in practice.

[0096] Reference Figure 11 This is a structural schematic diagram of a force sensing device according to an embodiment of the present disclosure. Based on, Figure 7 The structure shown includes a sensor 21 comprising a Wheatstone bridge circuit 211 and an amplifier circuit 212. An arm of the first Wheatstone bridge circuit 211 includes a strain-sensitive element 2110, which serves as part 210 of the sensor 21. The amplifier circuit 212 includes an operational amplifier 2120. The inverting and non-inverting input terminals of the operational amplifier 2120 are coupled to the two output terminals of the Wheatstone bridge circuit 211, respectively. The output terminal of the first operational amplifier 2120 is coupled to the input terminal of the comparator 23. The first signal V... OUT1 This includes the signal output from the output terminal of operational amplifier 2120.

[0097] Those skilled in the art will understand that the topology of the Wheatstone bridge circuit 211 and amplifier circuit 212 is merely exemplary, and other variations of the topology can be obtained without inventive effort. For example, any resistor in the Wheatstone bridge circuit 211 can be replaced with any number of resistors connected in series, parallel, or a combination of both. As another example, the operational amplifier 2120 can be connected in a closed-loop mode, a negative feedback mode, a low-pass filter mode, or an integrator circuit mode instead of the open-loop mode depicted. Furthermore, the connection between the two output terminals of the Wheatstone bridge circuit 211 and the two input terminals of the operational amplifier 2120 can be switched, i.e., the signal V... IN1 It is input to the non-inverting input terminal, and the signal V IN2 It is input to the inverting input terminal.

[0098] As described above, the first change and the second change can be implemented as the first signal V, respectively. OUT1 The higher and lower frequency components in the signal. Therefore, the second change can be obtained from the first signal V through frequency filtering. OUT1 Frequency filtering is typically achieved by setting a threshold frequency, where frequency components on one side of the threshold frequency are removed, while those on the other side are retained. Therefore, the more the first and second changes are separated in frequency, the better the filtering result. Since the frequency of the first change is primarily determined by the deformation rate of the deformable portion, it is more convenient to reduce the frequency of the second change by modifying the structure of the force sensing device 20. That is, heat conduction from the deformable portion 11 to a portion 210 of the sensor 21 can be delayed, thus slowing down the second change and shifting it to a lower frequency region, which improves the filtering result.

[0099] In some embodiments, the force sensing device 20 further includes a flexible layer 25 attached to the deformable portion. A portion 210 of the sensor 21 is attached to the deformable portion 21 via at least a portion of the flexible layer 25. The flexible layer 25 is configured to delay thermal conduction from the deformable portion 11 to the portion 210 of the sensor 21.

[0100] Reference Figure 12b and Figure 12c These are schematic structural diagrams of cross-sectional views of a portion of a sensor attached to a deformable part according to embodiments of this disclosure. Figure 12bIn this configuration, a flexible layer 25 is located between a portion 210 of the sensor 21 and the deformable portion 11. The flexible layer 25 can serve as an adhesive layer or intermediate layer for attaching the portion 210 of the sensor 21 to the deformable portion 11. It should be noted that the portion 210 of the sensor 21 can operate as an integrated structure together with the flexible layer 25, or it can operate as a separate structure independent of the flexible layer 25. In the following description, the attachment of a strain gauge to the deformable portion 11 is used as an example. In one embodiment, the metal foil pattern of the strain gauge can be used as a portion 210 of the sensor 21, and the backing layer of the strain gauge can be used as the flexible layer 25, such as... Figure 13a As shown. In this case, the strain gauge is directly attached to the deformable portion. In another embodiment, the entire strain gauge, including the metal foil pattern and the backing layer, can be used as part 210 of sensor 21, and the flexible layer is a separate layer located between the strain gauge and the deformable portion, as shown. Figure 13b As shown. In this case, the strain gauge is attached to the deformable portion via a separate layer.

[0101] exist Figure 12c In this configuration, a portion 210 of the sensor 21 is embedded in the flexible layer 25. Therefore, the flexible layer 25 can serve as an adhesive layer for attaching the portion 210 of the sensor 21 to the deformable portion 11, and the flexible layer 25 additionally or alternatively serves as a protective layer on the portion 210 of the sensor 21. Similarly, the portion 210 of the sensor 21 can operate as an integrated structure together with the flexible layer 25, or it can operate as a separate structure independent of the flexible layer 25.

[0102] The flexible layer 25 can delay heat conduction from the deformable portion 11 to a portion 210 of the sensor 21. In a first embodiment, the flexible layer 25 can be made of a thermally insulating material. That is, the flexible layer 25 has low thermal conductivity, thereby hindering heat flow through the flexible layer. In a second embodiment, the flexible layer can be a heat-diffusing layer, which in particular has anisotropic thermal conductivity between the direction along the thickness and the direction parallel to the layer surface.

[0103] The function of the heat diffusion layer is briefly illustrated below. (For reference...) Figure 14 This is a schematic diagram of heat conduction through a flexible layer according to an embodiment of the present disclosure. In this embodiment, a heat diffusion layer is used as the flexible layer 25. Figure 14As shown, heat is transferred from the deformable portion 11 to a portion 210 of the sensor 21 via the flexible layer 25. When heat flows from the deformable portion 11 into the flexible layer 25, the heat conduction at each location within the flexible layer 25 can be decomposed into two heat fluxes: a vertical flux along the thickness of the flexible layer and a horizontal flux in a plane perpendicular to that thickness. The vertical flux is transferred to the portion 210 of the sensor 21. The horizontal flux is transferred parallel to the interface between the deformable portion 11 and the flexible layer 25. The vertical flux determines the rate of heat transfer along the thickness, i.e., the rate of heat transfer to the portion 210 of the sensor 21. The horizontal flux determines the rate of heat transfer along a plane perpendicular to the thickness, i.e., the rate of heat diffusion within the flexible layer 25. It should be understood that the more heat diffuses within the flexible layer 25, the less heat is transferred to the portion 210 of the sensor 21, and the more the heat conduction from the deformable portion 11 to the portion 210 of the sensor 21 is delayed.

[0104] The ratio of vertical flux to horizontal flux depends on the thermal conductivity of the flexible layer 25 along its thickness and the thermal conductivity of the flexible layer 25 in a plane perpendicular to its thickness, respectively. To increase heat diffusion within the flexible layer 25, the flexible layer 25 can be made of a material with a thermal conductivity along its thickness that is less than that perpendicular to its thickness. Typically, the thermal conductivity along its thickness is one-tenth of the thermal conductivity perpendicular to its thickness. In one embodiment, the thermal conductivity along its thickness can be 1 W / mK, while the thermal conductivity in a plane perpendicular to its thickness can be 300 W / mK. Graphite sheets are a good candidate for the flexible layer 25 because heat is transferred more quickly within each sheet plane compared to the direction perpendicular to the sheet plane.

[0105] As described above, the flexible layer 25 may alternatively be made of a thermally insulating material such as rock wool or a paste. In some embodiments, the thermal conductivity is equal to or less than 0.1 W / mK.

[0106] The flexible layer 25 may also include a multilayer stacked structure. Each layer may be made of a separate thermally insulating material or may be a separate thermally diffusing layer. In one embodiment, at least one of the multilayers is made of a thermally insulating material, and at least another layer of the multilayers is a thermally diffusing layer.

[0107] Since heat diffuses continuously in a direction perpendicular to the thickness as it is transferred to a portion 210 of sensor 21, the delay in heat conduction can be further enhanced by increasing the thickness of the flexible layer 25. It should be noted that such a thickness should not be too large; otherwise, the deformation of the deformable portion 11 may be excessively buffered and not transferred to the portion 210 of sensor 21. Therefore, the thickness of the flexible layer 25 should be determined based on both the requirements for heat conduction delay and deformation detection sensitivity. In practice, the thickness of a portion of the flexible layer 25 (i.e., the flexible layer 25 located between the portion 210 of sensor 21 and the deformable portion 11) is typically between 25 μm and 500 μm.

[0108] Furthermore, the flexible layer 25 attached to the deformable portion 11 deforms together with the deformable portion 11. It should be understood that the deformation transmitted from the deformable portion 11 to a portion 210 of the sensor 21 will not be delayed by the flexible layer 25, provided that the flexible layer 25 is not highly elastic. Therefore, only the second change can be transferred to a lower frequency. Thus, the flexible layer 25 is able to separate the first and second changes in the frequency domain, facilitating the filter 22 in retaining the first signal V. OUT1 The first change is performed while the second change is removed.

[0109] Reference Figure 15 An example of the effect of thermal conduction delay is shown therein. Figure 15 This is a schematic diagram illustrating the temperature change over time when a sensor is attached to a deformable portion, with or without a flexible layer, according to an embodiment of this disclosure. In this example, the deformable portion is a metal surface. It can be seen that when the deformable portion is heated, the temperature rise of the sensor is slower than that of the deformable portion, and the temperature rise is further delayed when a flexible layer is applied between a portion of the sensor and the deformable portion.

[0110] Further reference Figure 16 It is a schematic diagram illustrating the changes in force (or strain) and temperature signals of a deformable portion according to embodiments of this disclosure. Figure 16 In the diagram, solid lines indicate the strain-sensitive element 2110 is attached to the deformable portion 11 via the flexible layer 25, short dashed lines indicate the strain-sensitive element 2110 is not attached to the deformable portion 11 via the flexible layer 25, and long dashed lines indicate the reference signal or threshold signal as marked. Assuming device 20 employs... Figure 8 The structure shown and the sensor employs, as Figure 11 The structure shown. (And) Figure 6 Similarly, the temperature of the deformable part 11 is gradually reduced as an example.

[0111] like Figure 16As shown, the temperature of a portion 210 (strain-sensitive element 2110) of sensor 21 decreases with the temperature of the variable portion 11. (The last sentence appears to be incomplete and possibly refers to a different part of the sensor.) Figure 15 Similarly, the temperature change over time of the strain-sensitive element 2110 is slower than that of the deformable portion 11, and this time change can be further delayed when the flexible layer 25 is applied. Even if the deformable portion 11 does not deform, the inverted input signal V of the first operational amplifier 2120... IN1 It also gradually decreased. (And) Figure 6 V in OUT Similarly, for the first signal V OUT1 First reference signal V REF1 It will drift to a higher level regardless of the presence or absence of the flexible layer 25. Similar to the temperature of the strain-sensitive element 2110, when the flexible layer 25 is applied, the first reference signal V... REF1 The drift was also delayed.

[0112] With Figure 6 The example shown is different; the first signal V is received. OUT1 The filter 22 is able to remove the first reference signal V REF1 The drift is slower than the change caused by deformation (e.g., the valley that appears at time t0). Therefore, the second signal V output from filter 22... OUT2 Excluding drift, therefore, in both cases with and without the flexible layer 25, the second reference signal V REF2 It remains at a fixed level. That is, the second reference signal V... REF2 With threshold signal V TH The difference between them remains constant. At time t0, from the second reference signal V... REF2 The second signal V is decreasing OUT2 Able to reach the threshold signal V TH This is similar to what should happen before the temperature of the deformable part 11 decreases. The second signal V OUT2 The bottom of the valley is below the threshold signal V TH Therefore, comparator 23 will convert the third signal V... OUT3 When the device is activated, the hardware module 12 is notified of the deformation of the deformable part, and the electronic device 10 is able to recognize the deformation around t0 and give an appropriate response.

[0113] In this embodiment, the threshold signal V TH Below the second reference signal V REF2 As an example, deformation causes the first signal V OUT1In the valley, the temperature is reduced, and compensation will prevent comparator 23 from giving a "false negative" result when determining whether the deformable portion 11 is deformed. Another implementation can be obtained by analogy, which also falls within the scope of this disclosure. For example, the threshold signal V TH Higher than the second reference signal V REF2 And deformation causes a second signal V OUT2 The peak value in the value. For example, the temperature is increased, and the compensation will prevent the comparator 23 from giving a "false positive" result when determining whether the deformable part 11 is deformed.

[0114] In some implementations, the threshold signal V TH This can include a set of signals based on the number of deformations to be identified by the hardware model 12. For example, a threshold signal V TH This may include one or more signals for compression, enabling hardware model 12 to recognize different degrees of compression (or squeeze input operations). Alternatively or additionally, a threshold signal V TH It may include one or more signals for tensioning, enabling the hardware model 12 to recognize different degrees of tension (or stretching input operations).

[0115] In some implementations, there may be multiple sensors 21 and / or multiple filters 22. For example, one sensor 21 may correspond to multiple filters 22, and each filter 22 is configured to remove the first signal V. OUT1 Different frequency components in the signal. Multiple filters 22 can be connected in series. In this case, the first signal V OUT1 It can pass through multiple filters in sequence, and only the frequency component corresponding to the deformation is retained in the second signal V. OUT2 Alternatively, multiple filters 22 can be connected in parallel. In this case, the first signal V OUT1 The second signal V can be passed through multiple filters to achieve the desired effect. OUT2 It includes multiple channels, and each channel can correspond to different types of deformation occurring at different speeds. For example, a filter 22 can correspond to multiple sensors 21. The multiple sensors 21 can be located in different regions of the deformable portion 11 to detect deformation at different locations.

[0116] According to embodiments of this disclosure, an electronic device is also provided. (See also...) Figure 7 and Figure 8 The electronic device 10 may include the aforementioned force sensing device 20, deformable region 11, and hardware module 12. Figure 7 In this configuration, hardware module 12 is configured to receive the second signal V. OUT2 And the state of hardware module 12 responds to the second signal V OUT2It changes with the change of state. Figure 8 In the middle, hardware module 12 is configured to receive the third signal V. OUT3 And the state of the hardware module responds to the third signal V. OUT3 The change is activated. In one implementation, the hardware module can be a controller, processor, display, speaker, switch, indicator light, etc. It should be understood that the hardware module can take other forms, as long as it can respond to the second signal V. OUT2 Or the third signal V OUT3 Change its state.

[0117] Electronic device 10 may include mobile phones, watches, glasses, head-mounted displays, earphones, keyboards, tablets, etc. In practice, the force sensing device 20 can be configured based on the structure of electronic device 10. For example, electronic device 10 is an earphone whose housing includes a deformable cap (outer shell), and the user can operate the earphone by squeezing or pressing the deformable cap. In this case, the force sensing device 20 can be located inside the housing, and a portion 210 of sensor 21 (or strain-sensitive element 2110) is attached to the inside of the deformable cap. Filter 22, comparator 23, and AD converter 24 can be integrated on one or more printed circuit boards (PCBs) enclosed by the housing. As another example, electronic device 10 is a foldable display device with a flexible display panel provided with a folding axis, and the user can open the device by opening the folded display panel. In this case, the force sensing device 20 can be located within the foldable area of ​​the display panel, and a portion 210 of sensor 21 (or strain-sensitive element 2110) is attached to the inside of the display at the foldable area. The filter 22, comparator 23, and AD converter 24 can be integrated into one or more processors in the display device.

[0118] According to embodiments of this disclosure, a method for force sensing is also provided. This method is applied to an electronic device and may include steps S101 and S102.

[0119] In step S101, the sensor generates a first signal. The first signal is determined based on the deformation of at least a portion of the sensor and the temperature of at least a portion of the sensor, and a portion of the sensor is attached to a deformable part of the electronic device.

[0120] In step S102, the filter receives the first signal and removes the variation from the first signal to obtain the second signal. This variation is caused by the temperature of a portion of the sensor.

[0121] In one embodiment, the method further includes steps S103 and S104.

[0122] In step S103, at least one comparator receives a second signal and determines whether the deformable portion is deformed based on the second signal and a threshold signal.

[0123] In step S104, the comparator generates a third signal. The third signal is activated in response to determining that the deformable part is deformed.

[0124] In one embodiment, the threshold signal may include a threshold signal for compression. Step S103 includes a comparator determining whether the deformable portion is compressed based on a second signal and the threshold signal for compression. A third signal is activated in response to the deformable portion being compressed.

[0125] In one embodiment, the threshold signal may include a threshold signal for tensioning. Step S103 includes a comparator determining whether the deformable portion is stretched based on a second signal and the threshold signal for tensioning. A third signal is activated in response to the deformable portion being stretched.

[0126] In one embodiment, multiple sets of sensors and filters are present, and these multiple sets of sensors and filters are located in different regions of the deformable portion. Step S103 includes a comparator determining whether each region in the different regions is deformed based on the output signal of the corresponding filter and a threshold signal.

[0127] The embodiments of this disclosure are described in a progressive manner, and each embodiment emphasizes its differences from other embodiments. Therefore, for the same or similar parts, one embodiment may refer to other embodiments. Since the methods disclosed in the embodiments correspond to the apparatus disclosed in the embodiments, the description of the methods is simple, and reference can be made to the relevant parts of the apparatus.

[0128] Based on the description of the disclosed embodiments, those skilled in the art can implement or use this disclosure. Various modifications to these embodiments may be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not limited to the embodiments described herein, but is recognized in the broadest possible scope based on the principles and novel features disclosed herein.

Claims

1. A device for force sensing, the device being located in an electronic device, wherein, The electronic device includes a deformable portion, and the device includes: A sensor configured to generate a first signal, wherein the first signal is determined based on deformation of at least a portion of the sensor and temperature of at least a portion of the sensor, and a portion of the sensor is attached to the deformable portion; The filter is configured as follows: Receive the first signal; and The change is removed from the first signal to obtain the second signal, wherein the change is caused by the temperature of a portion of the sensor; Also includes: A flexible layer attached to the deformable portion. A portion of the sensor is attached to the deformable portion via at least a portion of the flexible layer; One part of the sensor is a strain-sensitive element; The sensor includes a Wheatstone bridge circuit and an amplifier circuit. The arm of the Wheatstone bridge circuit includes the strain-sensitive element; The amplifier circuit includes an operational amplifier, the inverting and non-inverting input terminals of which are respectively coupled to the two output terminals of the Wheatstone bridge circuit, and the output terminal of the operational amplifier is coupled to the input terminal of the filter; and The first signal includes a first signal output from the output terminal of the operational amplifier; The strain-sensitive element is a strain gauge; Wherein, the strain-sensitive element is a metal foil pattern of a strain gauge, and the flexible layer is a backing layer on which the metal foil pattern is printed; A portion of the sensor is embedded within the flexible layer; The flexible layer includes: Layers made of thermal insulation material and A heat diffusion layer, wherein the thermal conductivity along the thickness of the heat diffusion layer is less than the thermal conductivity in a plane perpendicular to the thickness of the heat diffusion layer; Wherein, in the heat diffusion layer, the thermal conductivity along the thickness of the heat diffusion layer is one-tenth of the thermal conductivity in the plane perpendicular to the thickness of the heat diffusion layer.

2. The apparatus according to claim 1, further comprising at least one comparator, wherein, The comparator in the at least one comparator is configured to: Receive the second signal; Determine whether the deformable portion is deformed based on the second signal and the threshold signal; and A third signal is generated, wherein the third signal is activated in response to determining that the deformable portion is deformed.

3. The apparatus according to claim 2, further comprising an analog-to-digital converter, wherein: The filter is an analog filter, and the analog-to-digital converter is configured to convert the second signal into a digital signal before the second signal is input to the comparator; or The filter is a digital filter, and the analog-to-digital converter is configured to convert the first signal into a digital signal before inputting the first signal to the comparator.

4. The apparatus according to claim 1, wherein, The thermal conductivity of the thermal insulation material along the thickness of the flexible layer is equal to or less than 0.1 W / mK.

5. The apparatus according to claim 1, wherein, The thermal insulation material includes one or more graphite sheets, rock wool, or a paste.

6. The apparatus according to claim 1, wherein, The thickness of a portion of the flexible layer ranges from 25 μm to 500 μm.

7. The apparatus according to any one of claims 1 to 4, wherein, The filter includes at least one of a high-pass filter, a band-pass filter, or a band-stop filter.

8. The apparatus according to claim 3, wherein, The analog-to-digital converter is integrated with at least one of the sensor, the filter, or the comparator in the circuit.

9. The apparatus according to claim 3 or 8, wherein: The threshold signal includes a threshold signal for compression; The comparator is also configured to determine whether the deformable portion is being squeezed based on the second signal and the threshold signal for compression; as well as The third signal is activated in response to the deformation portion being squeezed.

10. The apparatus according to any one of claims 3 or 8, wherein: The threshold signal includes a threshold signal used for tensioning; The comparator is also configured to determine whether the deformable portion is stretched based on the second signal and the threshold signal for tensioning; as well as The third signal is activated in response to the stretching of the deformable portion.

11. An electronic device, comprising: The apparatus according to any one of claims 2, 3, 8, 9 and 10; The deformable portion; The hardware module is configured as follows: Receive a second signal, wherein the state of the hardware module changes in response to a change in the state of the second signal; or A third signal is received, wherein the state of the hardware module changes in response to the third signal being in an active state.

12. The electronic device according to claim 11, wherein, The hardware module includes at least one of the following: processor, controller, display, speaker, switch, or indicator light.

13. The electronic device of claim 11, comprising at least one of: a mobile phone, a watch, glasses, a head-mounted display device, earphones, a keyboard, or a tablet computer.

14. A method for force sensing, the method being applied to an electronic device, the method comprising: A first signal is generated by a sensor, wherein the first signal is determined based on the deformation of at least a portion of the sensor and the temperature of at least a portion of the sensor, and a portion of the sensor is attached to a deformable part of the electronic device; The first signal is received via a filter; and The filter removes the variation from the first signal to obtain the second signal, wherein the variation is caused by the temperature of a portion of the sensor; In this embodiment, a portion of the sensor is attached to the deformable portion via at least a portion of a flexible layer attached to the deformable portion, and the portion of the sensor is a strain-sensitive element; the sensor includes a Wheatstone bridge circuit and an amplifier circuit, the arm of the Wheatstone bridge circuit including the strain-sensitive element; the amplifier circuit includes an operational amplifier, the inverting input terminal and the non-inverting input terminal of the operational amplifier being coupled to the two output terminals of the Wheatstone bridge circuit respectively, and the output terminal of the operational amplifier being coupled to the input terminal of the filter; and the first signal includes the output from the operational amplifier... The first signal is output from the terminal; the strain-sensitive element is a strain gauge; wherein the strain-sensitive element is a metal foil pattern of the strain gauge, and the flexible layer is a backing layer on which the metal foil pattern is printed; a portion of the sensor is embedded in the flexible layer; the flexible layer includes: a layer made of thermally insulating material and a heat-diffusing layer, wherein the thermal conductivity along the thickness of the heat-diffusing layer is less than the thermal conductivity in a plane perpendicular to the thickness of the heat-diffusing layer; in the heat-diffusing layer, the thermal conductivity along the thickness of the heat-diffusing layer is one-tenth of the thermal conductivity in the plane perpendicular to the thickness of the heat-diffusing layer.

15. The method of claim 14, further comprising: The second signal is received by a comparator in at least one comparator; The comparator determines whether the deformable portion is deformed based on the second signal and the threshold signal; as well as A third signal is generated by the comparator, wherein the third signal is activated in response to determining that the deformable portion is deformed.

16. The method of claim 15, wherein: The threshold signal includes a threshold signal for compression; Determining whether the deformable portion is deformed includes: determining whether the deformable portion is compressed based on the second signal and the threshold signal for compression; as well as The third signal is activated in response to the deformation portion being squeezed.

17. The method according to claim 15 or 16, wherein: The threshold signal includes a threshold signal used for tensioning; Determining whether the deformable portion is deformed includes: determining whether the deformable portion is stretched based on the second signal and the threshold signal used for tensioning; as well as The third signal is activated in response to the stretching of the deformable portion.

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