CN114365071A

CN114365071A - Device for sensing force and electronic equipment

Info

Publication number: CN114365071A
Application number: CN202180004402.7A
Authority: CN
Inventors: 谷内寛直
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2021-02-10
Filing date: 2021-02-10
Publication date: 2022-04-15
Also published as: WO2022170542A1

Abstract

A device (10) for force sensing and an electronic apparatus (1) are provided. The electronic device (1) comprises a first deformable part (21) and a second deformable part (22). The device (10) comprises an operational amplifier (32, 105) and four branches (101-104) connected as a loop. Each branch (101-104) is connected to the first input terminal (V) of an operational amplifier (32, 105)_IN1) Or a second input terminal (V)_IN2) And a first terminal supplying a first voltage or a second terminal supplying a second voltage. At least two of the four branches (101-104) comprise a first strain sensor (111) attached to the first deformable portion (21) and a second strain sensor (112) attached to the second deformable portion (22), respectively. When the first deformable portion (21) is strained, the second deformable portion (22) is strained. The device (10) is brought into relation to the deformable part (2, 21-24) of the electronic equipment by reference to a sensor (111) attached to the associated deformable part (21-24)The sensitivity to force or strain is improved.

Description

Device for sensing force and electronic equipment

Technical Field

The present disclosure relates to the field of human-computer interaction, and in particular to an apparatus and method for force sensing and an electronic device.

Background

The rapid development of various electronic devices in people's daily life has been witnessed in recent decades. For ease of use, many input devices have been developed to assist users in interacting with electronic devices. Force-sensitive or strain-sensitive input devices are becoming increasingly popular because they provide a very convenient method of force sensing for user interaction with various types of electronic equipment. For example, a user can input an instruction to a mobile phone or a computer by simply touching, pressing, tapping, grasping, or stretching an operation interface with a finger or a stylus (stylus).

The operator interface provided with the force-or strain-sensitive input means is typically located at a deformable part of the electronic device, such as a virtual keyboard or virtual buttons on a flexible display, an elastic part of a plastic housing, a thinned part of a metal casing, etc. The force-sensitive input device or the strain-sensitive input device detects deformation of the operation interface, that is, detects a force or strain caused by an operation, and thereby enables the electronic apparatus to recognize such an operation. FIG. 1 is a schematic block diagram of a force-sensitive input device or a strain-sensitive input device of an electronic apparatus in the prior art. As shown in fig. 1, the force or strain sensitive input device includes an analog-to-digital comparator 4 and a force sensing circuit 3 located at an operator interface 2 of the electronic device 1. The force sensing circuit 3 is configured to generate an electrical signal and transmit the electrical signal to the analog-to-digital comparator 4. The analog-to-digital comparator 4 is configured to compare this signal with a threshold defined by a preset threshold signal and to output a signal whose state indicates the result of the comparison. The threshold value indicates a degree of deformation recognized by the electronic device. Then, the result is transmitted to the controller (or processor) 5, and the controller (or processor) 5 determines whether the operation region is deformed based on the state of the signal.

A key factor for evaluating the performance of a force-or strain-sensitive input device is the sensitivity, which refers to the minimum change in force that can cause a change in the state of the signal output from the analog-to-digital comparator 4. Highly sensitive input devices are able to detect small changes in force and can therefore give a more accurate response accordingly. For example, high sensitivity means that even a slight tap or touch on the operation interface 2 can be detected by the controller 5. As shown in fig. 1, the sensitivity of the input device is substantially determined by the sensitivity of the force sensing circuit 3 and the resolution of the analog-to-digital conversion in the analog-to-digital comparator 4. In practice, the current required for analog-to-digital conversion will increase exponentially with increasing resolution, resulting in high power consumption, which is incompatible with the trend of miniaturization and portability of the development of electronic devices. In some application scenarios, the controller (or processor) 5 may determine whether the operating region is deformed directly based on the analog signal output from the force sensing circuit, and in this case, analog-to-digital conversion is not necessary.

Therefore, the sensitivity of the force sensing circuit is very important to improve the performance of the force sensitive input device or the strain sensitive input device of the electronic device.

Disclosure of Invention

To solve the above technical problem, the following technical solutions are provided according to embodiments of the present disclosure.

In a first aspect, an apparatus for force sensing is provided according to embodiments of the present disclosure. The apparatus is applied to an electronic device comprising a first deformable portion and a second deformable portion. The apparatus includes an operational amplifier, a first branch, a second branch, a third branch, and a fourth branch. The first branch is connected between a first input terminal of the operational amplifier and a first terminal supplying a first voltage. The second branch is connected between the first input terminal and a second terminal supplying a second voltage, wherein the first voltage is different from the second voltage. The third branch is connected between the second input terminal and the first terminal of the operational amplifier. The fourth branch is connected between the second input terminal and the second terminal. A first strain sensitive branch of the first, second, third, and fourth branches includes a first strain sensor attached to the first deformable portion. A second strain sensitive branch of the first, second, third, and fourth branches includes a second strain sensor attached to the second deformable portion. The second deformable portion is strained when the first deformable portion is strained.

In one embodiment, the first strain sensitive branch is connected with the second strain sensitive branch at one of the first terminal, the second terminal, the first input terminal, or the second input terminal. When the first deformable portion is subjected to a first type of strain, the electrical parameter of the first strain sensor increases and the electrical parameter of the second strain sensor decreases. When the first deformable portion is subjected to a second type of strain, the electrical parameter of the first strain sensor decreases and the electrical parameter of the second strain sensor increases. The electrical parameter is resistance or capacitance. The first type of strain is compressive and the second type of strain is tensile, or the first type of strain is tensile and the second type of strain is compressive.

In one embodiment, the second deformable portion experiences the first type of strain when the first deformable region experiences the second type of strain. The second deformable portion experiences a second type of strain when the first deformable region experiences a first type of strain.

In one embodiment, the first strain sensitive branch is not connected to the second strain sensitive branch. When the first deformable portion is subjected to a first type of strain, both the electrical parameter of the first strain sensor and the electrical parameter of the second strain sensor increase. When the first deformable portion is subjected to a second type of strain, both the electrical parameter of the first strain sensor and the electrical parameter of the second strain sensor decrease. The electrical parameter is resistance or capacitance. The first type of strain is compressive and the second type of strain is tensile, or the first type of strain is tensile and the second type of strain is compressive.

In one embodiment, the second deformable portion experiences a first type of strain when the first deformable region experiences the first type of strain. The second deformable portion experiences a second type of strain when the first deformable region experiences the second type of strain.

In one embodiment, the electronic device further comprises a third deformable portion. A third strain sensitive branch of the first, second, third, and fourth branches includes a third strain sensor attached to a third deformable portion. The first strain sensitive branch is connected with the third strain sensitive branch at another of the first terminal, the second terminal, the first input terminal, or the second input terminal. When the first deformable portion experiences a first type of strain, the electrical parameter of the third strain sensor decreases. When the first deformable portion is subjected to a second type of strain, the electrical parameter of the third strain sensor increases.

In one embodiment, the third deformable portion experiences the first type of strain when the first deformable region experiences the second type of strain. The third deformable portion experiences a second type of strain when the first deformable region experiences the first type of strain.

In one embodiment, the electronic device further comprises a third deformable portion. A third strain sensitive branch of the first, second, third, and fourth branches includes a third strain sensor attached to a third deformable portion. The first strain sensitive branch is not connected to the third strain sensitive branch. When the first deformable portion is subjected to a first type of strain, the electrical parameter of the third strain sensor increases. When the first deformable portion is subjected to a second type of strain, the electrical parameter of the second strain sensor decreases.

In one embodiment, the third deformable portion experiences a first type of strain when the first deformable region experiences the first type of strain. The third deformable portion experiences a second type of strain when the first deformable region experiences the second type of strain.

In one embodiment, the electronic device further comprises a fourth deformable portion. A fourth strain sensitive branch of the first, second, third, and fourth branches includes a fourth strain sensor attached to a fourth deformable portion. When the first deformable portion is subjected to a first type of strain, the electrical parameter of the fourth strain sensor increases. When the first deformable portion is subjected to a second type of strain, the electrical parameter of the fourth strain sensor decreases.

In one embodiment, the fourth deformable portion experiences a first type of strain when the first deformable region experiences the first type of strain. The fourth deformable portion experiences a second type of strain when the first deformable region experiences the second type of strain.

In one embodiment, the electrical parameter is resistance. Each of the first, second, third and fourth strain sensors includes a strain gauge.

In one embodiment, the electrical parameter is capacitance. Each of the first, second, third and fourth strain sensors includes a capacitor. The capacitance of the capacitor increases when the strain sensor is subjected to tension, and decreases when the strain sensor is subjected to compression. Alternatively, the capacitance of the capacitor increases when the strain sensor is subjected to compression and decreases when the strain sensor is subjected to tension.

In one embodiment, the first deformable portion and the second deformable portion are located at a first sidewall and a second sidewall, respectively, of a housing of the electronic device. The first side wall and the second side wall are connected with each other.

In one embodiment, the first deformable portion and the second deformable portion are located at a first sidewall and a second sidewall, respectively, of a housing of the electronic device. The first side wall and the second side wall are parallel to each other.

In one embodiment, the first deformable portion, the second deformable portion, and the third deformable portion are located at a first sidewall, a second sidewall, and a third sidewall, respectively, of a housing of the electronic device. The first side wall is connected with the second side wall. The first side wall is connected with the third side wall.

In one embodiment, the first deformable portion, the second deformable portion, and the third deformable portion are located at a first sidewall, a second sidewall, and a third sidewall, respectively, of a housing of the electronic device. The first side wall is connected with the second side wall. The first side wall is parallel to the third side wall.

In one embodiment, the first deformable portion, the second deformable portion, the third deformable portion, and the fourth deformable portion are located at a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall, respectively, of a housing of the electronic device. The first side wall is connected with the second side wall. The first side wall is connected with the third side wall. The first side wall is parallel to the fourth side wall.

In one embodiment, the first deformable portion and the fourth deformable portion are located at the first sidewall. The second deformable portion and the third deformable portion are located at the second sidewall. The first side wall is connected with the second side wall.

In a second aspect, an electronic device is also provided according to an embodiment of the present disclosure. The electronic device comprises any of the above-described apparatuses, a first deformable part, a second deformable part, and a hardware module. The hardware module is configured to receive a signal output from an output terminal of the operational amplifier. The state of the hardware module changes in response to a signal state change.

In one embodiment, the hardware module includes at least one of: a processor, a controller, a display, a speaker, a switch, or an indicator light.

In one embodiment, an electronic device includes at least one of: a mobile phone, a watch, glasses, a head-mounted display device, an ear-bud headphone, a keyboard, or a tablet.

According to an embodiment of the present disclosure, an apparatus for force sensing is applied to an electronic device comprising a first deformable portion and a second deformable portion. The apparatus includes an operational amplifier and four branches connected as a loop. Each branch is connected between the first input terminal or the second input terminal of the operational amplifier and the first terminal supplying the first voltage or the second terminal supplying the second voltage. At least two of the four branches each include a first strain sensor attached to the first deformable portion and a second strain sensor attached to the second deformable portion. The second deformable portion is strained when the first deformable portion is strained. By referencing a sensor attached to the associated deformable portion, the sensitivity of the apparatus with respect to forces or strains exerted on the deformable portion of the electronic device is improved.

Drawings

The following is a brief description of the drawings of embodiments or conventional technologies to be applied to the present disclosure. A person skilled in the art can, without inventive effort, obtain other figures on the basis of the provided figures.

FIG. 1 is a schematic block diagram of a force-sensitive input device or a strain-sensitive input device of an electronic apparatus in the prior art;

FIG. 2 is a schematic view of a strain gauge and the operating state of the strain gauge in the conventional art;

FIG. 3 is a schematic block diagram of a force or strain sensitive input device based on strain gauges and Wheatstone (Wheatstone) bridges;

FIG. 4a is a schematic block diagram of a force sensing device according to an embodiment of the present disclosure;

FIG. 4b is a schematic block diagram of another force sensing device according to an embodiment of the present disclosure;

FIG. 5 is a schematic cross-sectional block diagram of a portion of a housing of an electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 6 is a schematic block diagram of another force sensing device according to an embodiment of the present disclosure;

FIG. 7 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 8 is a schematic block diagram of another force sensing device according to an embodiment of the present disclosure;

FIG. 9 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 10 is a schematic block diagram of another force sensing device according to an embodiment of the present disclosure;

FIG. 11 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 12 is a schematic block diagram of another force sensing device according to an embodiment of the present disclosure;

FIG. 13 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 14 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure;

FIG. 15 is a schematic cross-sectional block diagram of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure; and

fig. 16 is a schematic cross-sectional structural view of a portion of a housing of another electronic device including a force sensing apparatus according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, technical solutions in the embodiments of the present disclosure will be described with reference to the drawings in the embodiments of the present disclosure. It is to be understood that the described embodiments are only some, and not all, of the embodiments of the present disclosure. Any other embodiments that can be obtained by a person skilled in the art based on the embodiments of the disclosure without inventive efforts fall within the scope of the disclosure.

As described in the background, the sensitivity of a force-or strain-sensitive input device depends on the sensitivity of the force-sensing circuitry that outputs an analog signal based on the force or strain applied to the electronic device. Typically, a force sensing circuit or means for force sensing includes a force sensor configured to convert a force or strain into an electrical signal. In the following, details of the above technical problem are described, wherein a force sensor based on a strain gauge is taken as an example. Those skilled in the art will appreciate that such technical issues may be applicable to other types of force sensors, mutatis mutandis.

Referring to fig. 2, there is shown a strain gauge and a schematic view of the operation state of the strain gauge in the conventional art. The strain gauge is configured to measure strain on the object. A common type of strain gauge may consist of an insulating flexible backing supporting a metal foil pattern, as shown in fig. 2. The metal foil pattern comprises a winding pattern whose thickness is sensitive to strain and two terminals at both ends of the winding pattern. The strain gauge may be attached to the object by a suitable adhesive. When the object is deformed, the foil pattern will be deformed and the resistance of the foil pattern changes accordingly. Typically, compression of the object will thicken the metal foil pattern and thereby reduce the resistance of the strain gauge. Conversely, stretching of the object will thin the metal foil pattern and thereby increase the resistance of the strain gauge. In practice, two terminals may be connected into the arms of the wheatstone bridge, which is a common method for measuring resistance.

A typical configuration of a wheatstone bridge comprises an upper arm and a lower arm, each of which comprises two resistors connected at a common node. Three of the four resistors have a fixed resistance, while the other resistor has a variable (or to be measured) resistance. Both ends of the upper arm are connected to both ends of the lower arm, respectively, and the two connection nodes serve as two output terminals of the wheatstone bridge. Two common nodes in the upper and lower arms serve as power supply terminals to the wheatstone bridge. Thus, with the resistances of the three resistors and the voltage across the two power supply terminals known, the resistance to be measured can be derived from the voltage between the two output terminals. Other variations of the wheatstone bridge circuit are readily available to those skilled in the art and will not be described in detail herein.

Referring then to fig. 3, fig. 3 is a schematic block diagram of a strain sensitive input device or force sensitive input device based on a strain gauge and a wheatstone bridge. The configuration shown in fig. 3 is based on the configuration shown in fig. 1, wherein the force sensing circuit 3 comprises a wheatstone bridge circuit 30 and an operational amplifier 32. The lower arm of the wheatstone bridge circuit 30 includes a strain gauge 31, the strain gauge 31 serves as a variable (or to be measured) resistor, and the strain gauge 31 is provided on a deformable portion (such as an operation interface) 2 of the electronic device 1. Two output terminals of the Wheatstone bridge circuit 30 are respectively coupled to the inverting input terminal of the operational amplifier 32 anda non-inverting input terminal. An output terminal of the operational amplifier 32 is coupled to an input terminal of an analog-to-digital converter (ADC) 4. In fig. 3, signals at the inverting input terminal, the non-inverting input terminal, and the output terminal of the operational amplifier 32 are denoted as V, respectively_IN1、V_IN2And V_OUT. Presence of V_OUT＝A*(V_IN2-V_IN1) Where a is the gain of the operational amplifier 32.

Based on the structure as shown in fig. 3, the ADC may be provided with an algorithm for determining whether the deformation portion 2 is deformed. For example, the algorithm may include: will output signal V_OUTConverting into digital signals; determining the output signal V_OUTWhether or not it is lower (or higher) than a threshold signal V_TH(ii) a Indicating deformation of the deformable portion in the event of a positive determination; and indicating that the deformable portion is not deformed in the case of a negative determination.

Suppose the resistance of the strain gauge 31 is equal to R_1vAnd the fixed resistances of the other resistors in the Wheatstone bridge circuit 30 are respectively R as shown in FIG. 3₂、R₃And R₄. In this case, V_OUTThe output signal of (a) may be expressed as follows, where Δ V ═ V_cc-V_ss。

Since the force sensing unit operates as an analog element, the sensitivity of the force sensing unit 3 can be defined as the output signal V per unit force change_OUTA change in (c). Since the force applied to the operator interface is converted into the resistance of the strain gauge, the sensitivity of the force sensing circuit 3 can be measured as the output signal V_OUTRelative to R_1vIs expressed as a differential.

Thus, the sensitivity of the force sensing circuit 3 can be improved in three ways: increasing the gain a of the operational amplifier 32; increaseWith power supply voltage V_ccAnd V_ssThe difference between them; or reducing the resistance R of the bridge arm comprising the strain gauge_1v+R₂. However, the first approach will also amplify noise in the output signal and will reduce the stability factor of the circuit. The second and third ways will increase the current through the wheatstone bridge 31 and thus increase the power consumption of the force sensing circuit. Therefore, all three approaches are unsatisfactory, especially in case the electronic device 1 is a portable electronic device or a wearable electronic device.

According to embodiments of the present disclosure, a novel structure of an apparatus for force sensing is presented, wherein at least two strain sensors attached to different deformable parts of an electronic device are incorporated into a wheatstone bridge to improve the sensitivity of force sensing.

Referring to fig. 4a, 4b, 6, 8, 10 and 12, fig. 4a, 4b, 6, 8, 10 and 12 are schematic block diagrams of a device for force sensing according to an embodiment of the present disclosure. The apparatus for force sensing 10 is applied to an electronic device. The arrangement comprises a first branch 101, a second branch 102, a third branch 103, a fourth branch 104 and an operational amplifier 105. Similar to amplifier 32 in FIG. 3, operational amplifier 105 includes a carrier signal V_IN1And a carrier signal V_IN2And a second input terminal. The operational amplifier 105 further comprises a carrier signal V_OUTAn output terminal of (1). The first and second terminals are configured to supply power to the device 10, wherein the first terminal supplies a first voltage V_ccAnd the second terminal supplies a second voltage V_ss。

The first branch 101 is connected between the first input terminal and the first terminal. The second branch 102 is connected between the first input terminal and the second terminal. The third branch 103 is connected between the second input terminal and the first terminal. The fourth branch 104 is connected between the second input terminal and the second terminal. At least two of the four branches 101 to 104 serve as strain sensitive branches, i.e. branches configured to detect a strain or force exerted on a deformable part of the electronic device. Each strain sensitive branch comprises a strain sensor attached to a respective deformable portion. Thus, there are at least two sensors attached to at least two deformable parts of the electronic device, respectively. When one of the at least two deformable portions is strained, the other or other deformable portions is also strained. While strain may be triggered in various ways. In one embodiment, a force associated with one operation may be simultaneously applied on the deformable portion, for example when the mobile phone is gripped in the hand or when the user pinches the ear bud earphone. In another embodiment, the deformable portions may be physically connected such that strain may be transmitted from one to the other.

Due to the simultaneous strain, the electrical parameters of each strain sensor will drift simultaneously. When the strain sensors are properly set, the drift corresponding to each strain sensor may cause the output signal V_OUTChanging in the same direction (i.e., increasing or decreasing). In this case, even if the force or strain applied to any deformable portion is not changed, the output signal V_OUTWill also undergo a larger change than if only one strain sensor and one deformable portion were relied upon as shown in fig. 3. Thus, by referencing another sensor and referencing the associated deformable portion, the sensitivity of the apparatus 10 with respect to forces or strains exerted on the deformable portion of the electronic device is improved. In addition, the gain A of the operational amplifier, the power supply voltage V_ccAnd V_ssAnd the fixed resistance of the resistor in the circuit shown in fig. 3 may be constant and therefore there is no need to reduce the stability factor or increase power consumption.

Hereinafter, five embodiments are provided in conjunction with the accompanying drawings to explain embodiments of the present disclosure.

First embodiment

Refer to fig. 4 a. In the first embodiment, the first branch 101 serves as a first strain sensitive branch and the second branch 102 serves as a second strain sensitive branch. The first strain sensitive branch comprises a first strain sensor 111 attached to a first deformable part 21 of the electronic device. The second strain sensitive branch comprises a second strain sensor 112 attached to the second deformable portion 22 of the electronic device. The third and fourth branches each include a resistor having a fixed resistance.

Assuming that the resistance of the first strain sensor is equal to R_1vThe resistance of the second strain sensor is equal to R_2vThe resistance of the resistor in the third branch is equal to R₃And the resistance of the resistor in the fourth branch is equal to R₄. Similar to equation (1), the output signal V_OUTCan be expressed as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

The sensitivity of the device 10 with respect to the force exerted on the first deformable portion 21 can be deduced as follows.

When it is assumed that R is_2v＝R₂I.e. when the second strain sensor of the reference state, such as the zero strain state, has the same resistance as the corresponding fixed resistor as shown in fig. 3, a fair comparison can be made. It is apparent that the sensitivity in formula (5) will be greater than in formula (2) as long as dR_2v*dR_1vLess than 0. I.e. R when the first deformable part is subjected to strain_1vAnd R_2vOne increases and the other decreases. Typically, strain refers to compression or tension, and the resistance of the force sensor will increase in one of compression and tension and decrease in the other. For example, R in the case where the first deformable part is subjected to compression_1vIs increased and R_2vReduced while being subjected to stretching in the first deformable portionIn the case of (A) R_1vDecrease and R_2vAnd (4) increasing. For another example, R where the first deformable portion is subjected to stretching_1vIs increased and R_2vReduced, while R is in the case of the first deformable part undergoing compression_1vDecrease and R_2vAnd (4) increasing.

The four branches in fig. 4a are illustrated and calculated as resistive elements above, primarily for the sake of clear comparison with the structure shown in fig. 3. Note that the present disclosure is not limited thereto, and any branch may include another element, such as a capacitor. For example, the resistors in fig. 4a are replaced by capacitors and the strain sensors are all capacitive elements.

Assuming that the capacitance of the first strain sensor is equal to C_1vThe capacitance of the second strain sensor is equal to C_2vThe fixed capacitance of the capacitor in the third branch is equal to C₃And the fixed capacitance of the capacitor in the fourth branch is equal to C₄. In this case, equation (3) may be rewritten as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

Similarly, the sensitivity of the device 10 with respect to the force exerted on the first deformable portion 21 can be deduced as follows.

For comparison, the resistive elements in fig. 3 are also replaced by corresponding capacitive elements, and the sensitivity of the force sensing circuit 3 may be determined as the output signal V_OUTWith respect to alleged C_2vIs expressed as a differential.

It is apparent that the sensitivity can be increased for the capacitance case when the following condition is satisfied. When the first deformable portion 21 is subjected to a first type of strain, C_1vIncrease and C_2vReduced and/or when the first deformable portion 21 is subjected to a second type of strain, C_1vIs reduced and C_2vAnd (4) increasing. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

Furthermore, the sensitivity of the device 10 with respect to the force exerted on the second deformable portion 22 can be similarly obtained, as shown in equations (10) and (11). The conclusions regarding the first deformable portion 21 apply mutatis mutandis to the second deformable portion 22. I.e. when the first deformable portion 21 is subjected to a first type of strain, R_1vIs increased and R_2vReduce, and/or when the first deformable portion 21 is subjected to a second type of strain, R_1vDecrease and R_2vAnd (4) increasing. For the capacitive case, C when the first deformable portion 21 is subjected to a first type of strain_1vIncrease and C_2vReduced and/or when the first deformable portion 21 is subjected to a second type of strain, C_1vIs reduced and C_2vAnd (4) increasing. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

It should be noted that the first embodiment is intended to describe the case where the first and second strain-sensitive branches are "adjacent", i.e. the first and second strain-sensitive branches are connected at one of the first, second, first and second input terminals. Thus, there may be two possibilities: one possibility is that the first and second strain sensitive branches are two branches connecting the first and second terminals; another possibility is that the first and second strain sensitive branches are two branches connecting the first and second input terminals. The former case may refer to the structure shown in fig. 4a, while the latter case may refer to the structure shown in fig. 4b, as discussed below.

In fig. 4b, the first branch is taken as the first strain sensitive branch and the third branch as the second strain sensitive branch as an example. The second branch 112 and the fourth branch 114 each comprise a resistor having a fixed resistance. Assuming that the resistance of the first strain sensor is equal to R_1vThe resistance of the second strain sensor is equal to R_3vThe resistance of the resistor in the second branch is equal to R₂And the resistance of the resistor in the fourth branch is equal to R₄. Similar to equation (6), the output signal V_OUTCan be expressed as follows.

In this case, the output signal V_OUTThe differential of (c) can be written as follows.

Still, the sensitivity can be increased when the following conditions are satisfied. When the first deformable portion 21 is subjected to a first type of strain, R_1vIs increased and R_3vReduce, and/or when the first deformable portion 21 is subjected to a second type of strain, R_1vDecrease and R_3vAnd (4) increasing. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

Similarly, the sensitivity of the device 10 with respect to the force exerted on the second deformable portion 22 may be similarly derived, as shown in equation (12). The conclusions regarding the first deformable portion 21 apply mutatis mutandis to the second deformable portion 22, which is not repeated here.

The sensitivity of the capacitance case can be derived similarly as in equations (16) and (17). Still, when the following conditions are satisfied, the sensitivity can be increased. When the first deformable portion 21 (or the second deformable portion 22) is subjected to a first type of strain, C_1vIncrease and C_3vReduce, and/or when the first deformable portion 21 (or the second deformable portion 22) is subjected to a second type of strain, C_1vIs reduced and C_3vAnd (4) increasing. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

That is, where the first strain sensor and the second strain sensor are located in two "adjacent" branches, the sensitivity of the device 10 with respect to forces exerted on either deformable portion will be improved, so long as the electrical parameters of the first strain sensor and the electrical parameters of the second strain sensor change in different directions when such deformable portions are strained. The electrical parameter may be capacitance or resistance.

The first strain sensor 111 and the second strain sensor 112 in the above case may be provided in various ways in the electronic device. Referring to fig. 5, a cross-section of a portion of a housing of an electronic device including an apparatus for force sensing according to an embodiment of the present disclosure is shown. The first deformable portion 21 is located at a first side wall 210 of the housing of the electronic device and the second deformable portion 22 is located at a second side wall 220 of the housing. That is, the first strain sensor 111 is attached to the first sidewall 210 at the first deformable portion 21, and the second strain sensor 112 is attached to the second sidewall 220 at the second deformable portion 22. For better illustration, the first deformable portion 21 and the second deformable portion 22 are not shown in fig. 5. The dashed box in the figure represents a component enclosed by the housing of the electronic device, which may be a printed circuit board, a battery, a gravity sensor, etc. The first sidewall 210 and the second sidewall 220 may be connected. Thus, when a force (indicated by the open arrows) is applied on the first deformable portion 21, the housing enclosing the electronic device may be compressed in the direction of the force and stretched in a direction perpendicular to the direction of the force (wherein the strain of the side walls is indicated by the solid arrows). Thus, the first deformable portion 21 is subjected to tension and the second deformable portion 22 is subjected to compression. Similarly, when an opposing force is applied on the first deformable portion 21 (e.g., when the first sidewall is pulled or pushed upward), the first deformable portion 21 undergoes compression and the second deformable portion 22 undergoes tension. With the same type of strain (i.e., tensile or compressive), the electrical parameters of both the first and

second strain sensors

111, 112 may change toward the same direction (i.e., increase or decrease). In this case, the above configuration will ensure that the electrical parameter of the first strain sensor 111 and the electrical parameter of the second strain sensor 112 change in different directions when any deformable portion is strained.

Note that the structure shown in fig. 5 is merely exemplary, and the first and

second sidewalls

210 and 220 may be otherwise configured. For example, the first sidewall 210 and the second sidewall 220 may not be directly connected, but connected via another sidewall that may conduct strain. For another example, the first sidewall 210 and the second sidewall 220 may not be connected, but one is extended and the other is compressed in one operation by the user. In addition, the first strain sensor 111 and the second strain sensor 112 may be provided in other manners. For example, each strain sensor may be attached at the other side of the respective sidewall. For another example, two strain sensors may be attached to opposite sides of a flexible member having a thickness such that one undergoes tension and the other undergoes compression when the flexible member is bent.

Second embodiment

The second embodiment is intended to describe the case where the first and second strain sensitive branches are "opposite", i.e. the first and second strain sensitive branches are not connected in a wheatstone bridge configuration.

Referring to fig. 6, in the second embodiment, the first branch 101 serves as a first strain sensitive branch, and the fourth branch 104 serves as a second strain sensitive branch. Similar to fig. 4a and 4b, the first strain sensitive branch comprises a first strain sensor 111 attached to a first deformable part 21 of the electronic device. The second strain sensitive branch comprises a second strain sensor 112 attached to the second deformable portion 22 of the electronic device. The second and third branches each include a resistor having a fixed resistance.

Assuming that the resistance of the first strain sensor is equal to R_1vThe resistance of the second strain sensor is equal to R_4vThe resistance of the resistor in the second branch is equal to R₂And the resistance of the resistor in the third branch is equal to R₃. Output signal V_OUTCan be expressed as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

When it is assumed that R is_4v＝R₄That is, when the second strain sensor 112 in a reference state (such as a zero strain state) has the same resistance as the corresponding fixed resistor as shown in FIG. 3, a fair comparison can be made. It is apparent that the sensitivity in formula (20) will be greater than in formula (2) as long as dR_1v*dR_4vIs more than 0. I.e. R when the first deformable part is subjected to strain_1vAnd R_4vEither both increasing or both decreasing. For example, R in the case where the first deformable part is subjected to compression_1vAnd R_4vAre reduced while R is in the case of the first deformable part undergoing stretching_1vAnd R_4vAre increased. For another example, R where the first deformable portion is subject to compression_1vAnd R_4vBoth increase, while R is the case when the first deformable part is subjected to stretching_1vAnd R_4vIs reduced.

Similar conclusions can be drawn for the capacitive case, as in the first embodiment. Assuming that the capacitance of the first strain sensor is equal to C_1vThe capacitance of the second strain sensor is equal to C_4vThe fixed capacitance of the capacitor in the second branch is equal to C₂And the fixed capacitance of the capacitor in the third branch is equal to C₃. In this case, equation (18) may be rewritten as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

It is apparent that the sensitivity can be increased for the capacitance case when the following condition is satisfied. When the first deformable portion 21 is subjected to a first type of strain, C_1vAnd C_2vAre reduced and/or C when the first deformable portion 21 is subjected to a second type of strain_1vAnd C_2vAre increased. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

In the circuit topology shown in FIG. 6, V_ccAnd V_ssAre interchangeable, and V_INlAnd V_IN2Are interchangeable. Thus, the first strain sensor 111 and the second strain sensor 112 are symmetrical elements in the circuit topology, and the above conclusions can be applied to the force exerted on the second deformable portion 22. The equation for the resistance case and the equation for the capacitance case are as follows.

That is, where the first strain sensor 111 and the second strain sensor are located in two "opposing" branches, the sensitivity of the device 10 with respect to forces exerted on either deformable portion will be improved, as long as the electrical parameters of the first strain sensor and the electrical parameters of the second strain sensor change toward the same direction when such deformable portions are strained. The electrical parameter may be capacitance or resistance.

The first strain sensor 111 and the second strain sensor 112 in the second embodiment may be provided in various ways in the electronic device. Referring to fig. 7, fig. 7 shows a cross-section of a portion of a housing of another electronic device including an apparatus for force sensing according to an embodiment of the present disclosure. Similar to fig. 5, the first strain sensor 111 is attached to the first sidewall 210 at the first deformable portion 21 and the second strain sensor 112 is attached to the second sidewall 220 at the second deformable portion 22. The first sidewall 210 and the second sidewall 220 may be parallel. When a force (indicated by either the open arrows) is applied on the first deformable portion 21 or the second deformable portion 22, the housing enclosing the electronic device may be compressed in the direction of the force and extended in a direction perpendicular to the direction of the force (where the strain of the side walls is indicated by the solid arrows). Thus, both the first deformable portion 21 and the second deformable portion 22 are subjected to stretching. Similarly, when an opposing force is applied on the first deformable portion 21 or the second deformable portion 22 (e.g., when the respective side wall is pulled or pushed upward), both the first deformable portion 21 and the second deformable portion 22 undergo compression. Similar to the first embodiment, the electrical parameters of both the first and

second strain sensors

111, 112 may change in the same direction (i.e., increase or decrease) with the same type of strain (i.e., tensile or compressive). In this case, the above configuration will ensure that the electrical parameter of the first strain sensor 111 and the electrical parameter of the second strain sensor 112 change toward the same direction when any deformable portion is strained.

Note that the structure shown in fig. 7 is merely exemplary, and the first and

second sidewalls

210 and 220 may be otherwise configured. For example, the first sidewall 210 and the second sidewall 220 may not be exactly parallel, but form an angle as long as both the first sidewall 210 and the second sidewall 220 are extended or compressed in one operation by a user. In addition, the first strain sensor 111 and the second strain sensor 112 may be provided in other manners. For example, two strain sensors may be attached to the same side wall, i.e. the first deformable portion 21 and the second deformable portion 22 are located at the same side wall.

Third embodiment

The third embodiment is based on the first embodiment and is intended to describe the case where the third strain sensitive branch is "adjacent" to the first strain sensitive branch and "opposite" to the second strain sensitive branch. That is, the third strain sensitive branch is connected with the first strain sensitive branch and not with the second strain sensitive branch via the other of the first terminal, the second terminal, the first input terminal, and the second input terminal.

Referring to fig. 8, fig. 8 is based on fig. 4 a. In the third embodiment, the electronic device further comprises a third deformable portion 23, and the third branch 103 also serves as a third strain sensitive branch. The third strain sensitive branch comprises a third strain sensor 113 instead of a resistor as shown in fig. 4 a. A third strain sensor 113 is attached to the third deformable portion 23. Assuming that the resistance of the first strain sensor is equal to R_3v。

Output signal V_OUTCan be expressed as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

When it is assumed that R is_3v＝R₃I.e. when the third strain sensor 113 of a reference state, such as a zero strain state, has the same resistance as the corresponding fixed resistor as shown in fig. 4a, a fair comparison can be made. It is apparent that the sensitivity in equation (28) will be greater thanSensitivity in formula (5) as long as dR_1v-dR_3vLess than 0. I.e. R when the first deformable part is subjected to strain_1vAnd R_3vOne increases and the other decreases. Typically, strain refers to compression or tension, and the resistance of the force sensor will increase in one of compression and tension and decrease in the other. For example, R in the case where the first deformable part is subjected to compression_1vIs increased and R_3vReduced, while R is in the case of the first deformable part undergoing stretching_1vDecrease and R_3vAnd (4) increasing. For another example, R where the first deformable portion is subjected to stretching_1vIs increased and R_3vReduced, while R is in the case of the first deformable part undergoing compression_1vDecrease and R_3vAnd (4) increasing.

Similar conclusions can be drawn for the capacitive case, as in the first embodiment. Assuming that the capacitance of the third strain sensor is equal to C_3v. In this case, equation (6) may be rewritten as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

Compared with equation (8), it is apparent that the sensitivity can be increased for the capacitance case when the following condition is satisfied. When the first deformable portion 21 is subjected to a first type of strain, C_1vIncrease and C_3vIs reduced byAnd/or when the first deformable portion 21 is subjected to a second type of strain, C_1vIs reduced and C_3vAnd (4) increasing. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

That is, in the case where the first strain sensor 111 and the third strain sensor 113 are located in two "adjacent" branches, the sensitivity of the device 10 with respect to the force exerted on the first deformable portion 21 will be further improved, as long as the electrical parameters of the first strain sensor 111 and the third strain sensor 113 change towards different directions when the first deformable portion 21 is strained. The electrical parameter may be capacitance or resistance.

The third strain sensor 113 in the present embodiment may be provided in the electronic apparatus in various ways. Referring to fig. 9, fig. 9 shows a cross-section of a portion of a housing of another electronic device including an apparatus for force sensing according to an embodiment of the present disclosure. Based on the structure as shown in fig. 5, the third deformable portion is located at the third side wall 230 of the housing of the electronic device. That is, the third strain sensor 113 is attached to the third side wall 230 at the third deformable portion 23. The third deformable portion 23 is not shown in fig. 9, similar to the other deformable portions. The first sidewall 210 and the third sidewall 230 may be connected. Thus, when a force (indicated by the open arrow) is exerted on the first deformable portion 21, the first deformable portion 21 is subjected to tension, while both the second deformable portion 22 and the third deformable portion 23 are subjected to compression. Similarly, when an opposing force is applied on the first deformable portion 21 (e.g., when the first sidewall is pulled or pushed upward), the first deformable portion 21 undergoes compression while both the second deformable portion 22 and the third deformable portion 23 undergo tension. With the same type of strain (i.e., tensile or compressive), the electrical parameters of both the first and

third strain sensors

111, 113 may change toward the same direction (i.e., increase or decrease). In this case, the above configuration will ensure that the electrical parameter of the first strain sensor 111 and the electrical parameter of the third strain sensor 113 change towards different directions when the first deformable portion 21 is strained.

Note that the structure shown in fig. 5 is merely exemplary, and the third side wall 230 may be configured in other ways. For example, the first sidewall 210 and the third sidewall 230 may not be directly connected, but connected via another sidewall that may conduct strain. For another example, the first sidewall 210 and the third sidewall 230 may not be connected, but one is extended and the other is compressed in one operation by the user. Furthermore, the third strain sensor 113 may be provided in other manners. For example, the third strain sensor 113 may be attached at the other side of the third sidewall 230. For another example, the third strain sensor 113 and the first strain sensor 111 may be attached to opposite sides of a flexible member having a thickness such that one undergoes tension and the other undergoes compression when the flexible member is bent. In one embodiment, the third strain sensor 113 may be attached to the same sidewall as the second strain sensor, i.e. at the second sidewall 220.

Fourth embodiment

The fourth embodiment is based on the first embodiment and is intended to describe the case where the third strain-sensitive branch is "opposite" the first strain-sensitive branch and "adjacent" the second strain-sensitive branch. That is, the third strain sensitive branch is connected with the second strain sensitive branch and not with the first strain sensitive branch via the other of the first terminal, the second terminal, the first input terminal, and the second input terminal.

Referring to fig. 10, fig. 10 is based on fig. 4 a. In the third embodiment, the electronic device further comprises a third deformable portion 23, and the fourth branch 104 also serves as a third strain sensitive branch. The third strain sensitive branch comprises a third strain sensor 113 instead of a resistor as shown in fig. 4 a. A third strain sensor 113 is attached to the third deformable portion 23. Assuming that the resistance of the first strain sensor is equal to R_4v。

Output signal V_OUTCan be expressed as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

When it is assumed that R is_4v＝R₄I.e. when the third strain sensor 113 of a reference state, such as a zero strain state, has the same resistance as the corresponding fixed resistor as shown in fig. 4a, a fair comparison can be made. It is apparent that the sensitivity in formula (34) will be greater than the sensitivity in formula (5) as long as dR_1v*dR_4vIs more than 0. I.e. R when the first deformable part is subjected to strain_1vAnd R_4vEither both increasing or both decreasing. Typically, strain refers to compression or tension, and the resistance of the force sensor will increase in one of compression and tension and decrease in the other. For example, R in the case where the first deformable part is subjected to compression_1vAnd R_4vAre reduced while R is in the case of the first deformable part undergoing stretching_1vAnd R_4vAre increased. For another example, R where the first deformable portion is subject to compression_1vAnd R_4vBoth increase, while R is the case when the first deformable part is subjected to stretching_1vAnd R_4vIs reduced.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

Compared with equation (8), it is apparent that the sensitivity can be increased for the capacitance case when the following condition is satisfied. When the first deformable portion 21 is subjected to a first type of strain, C_1vAnd C_3vAll increase and/or C when the first deformable portion 21 is subjected to a second type of strain_1vAnd C_3vIs reduced. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

That is, in the case where the first strain sensor 111 and the third strain sensor 113 are located in two "opposite" branches, the sensitivity of the device 10 with respect to the force exerted on the first deformable portion 21 will be further improved, as long as the electrical parameters of the first strain sensor 111 and the third strain sensor 113 change towards the same direction when the first deformable portion 21 is strained. The electrical parameter may be capacitance or resistance.

The first deformable portion 111 in the fourth embodiment may be considered as the second deformable portion 112 or the third deformable portion 113 in the third embodiment, since the strain sensor attached thereto is comprised in a strain sensitive branch connected to the only "non-strain sensitive" branch of the four branches. That is, the sensitivity of the device with respect to the force exerted on the second deformable portion 112 or the third deformable portion 113 in the third embodiment will be the same as the sensitivity of the device with respect to the force exerted on the first deformable portion 111 in the fourth embodiment. For example, the sensitivity of the device with respect to the force exerted on the second deformable portion 112 in the third embodiment can be obtained by simply exchanging the subscripts "1 v" and "2 v" according to equations (34) and (37).

The third strain sensor 113 in the present embodiment may be provided in the electronic apparatus in various ways. Referring to fig. 11, fig. 11 shows a cross-section of a portion of a housing of another electronic device including an apparatus for force sensing according to an embodiment of the present disclosure. The details of the structure in fig. 11 may be referred to the details of the structure in fig. 9, except that the first sidewall 210 and the third sidewall 230 are parallel rather than connected. Thus, when a force (indicated by either the open arrow) is applied on the first deformable portion 21 or the third deformable portion 23, the housing enclosing the electronic device may be compressed in the direction of the force and extended in a direction perpendicular to the direction of the force (where the strain of the side walls is indicated by the solid arrows). Thus, both the first deformable portion 21 and the third deformable portion 23 are subjected to stretching. Similarly, when opposing forces are applied on the first deformable portion 21 or the third deformable portion 23 (e.g., when the respective sidewalls are pulled or pushed upward), both the first deformable portion 21 and the third deformable portion 23 experience compression. Similar to the third embodiment, the electrical parameters of both the first strain sensor 111 and the third strain sensor 113 may change toward the same direction (i.e., increase or decrease) under the same type of strain (i.e., tensile or compressive). In this case, the above configuration will ensure that the electrical parameter of the first strain sensor 111 and the electrical parameter of the third strain sensor 113 change toward the same direction when any deformable portion is strained.

Note that the structure shown in fig. 11 is merely exemplary, and the third side wall 230 may be configured in other ways. For example, the first sidewall 210 and the second sidewall 220 may not be exactly parallel, but form an angle as long as both the first sidewall 210 and the second sidewall 220 are extended or compressed in one operation by a user. Furthermore, the third strain sensor 113 may be provided in other manners. For example, the third strain sensor 113 may be attached at the other side of the third sidewall 230. For another example, the third strain sensor 113 may be attached to the same sidewall as the first strain sensor 111, i.e., at the first sidewall 210.

Fifth embodiment

The fifth embodiment is based on the third embodiment and is intended to describe the case where all four branches are strain sensitive branches. That is, the fourth strain-sensitive branch is connected with the second and third strain-sensitive branches via the other two of the first terminal, the second terminal, the first input terminal, and the second input terminal, but not with the first strain-sensitive branch.

Referring to fig. 12, fig. 12 is based on fig. 8. In the fifth embodiment, the electronic device further comprises a fourth deformable part 24, and the fourth branch 104 also serves as a fourth strain sensitive branch. The fourth strain sensitive branch includes a fourth strain sensor 114 instead of a resistor as shown in fig. 8. A fourth strain sensor 114 is attached to the fourth deformable portion 24. Assuming that the resistance of the first strain sensor is equal to R_4v。

Output signal V_OUTCan be expressed as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

When it is assumed that R is_4v＝R₄That is, the fourth strain sensor 114 in a reference state (such as a zero strain state) has a corresponding strain as shown in FIG. 8The same resistance is shown for the fixed resistors-a fair comparison can be made. It is apparent that the sensitivity in equation (40) will be greater than the sensitivity in equation (28) as long as dR_1v*dR_4vIs more than 0. I.e. R when the first deformable part is subjected to strain_1vAnd R_4vEither both increasing or both decreasing. Typically, strain refers to compression or tension, and the resistance of the force sensor will increase in one of compression and tension and decrease in the other. For example, R in the case where the first deformable part is subjected to compression_1vAnd R_4vAre reduced while R is in the case of the first deformable part undergoing stretching_1vAnd R_4vAre increased. For another example, R where the first deformable portion is subject to compression_1vAnd R_4vBoth increase, while R is the case when the first deformable part is subjected to stretching_1vAnd R_4vIs reduced.

Similar conclusions can be drawn for the capacitive case, as in the first embodiment. Assuming that the capacitance of the fourth strain sensor is equal to C_4v. In this case, equation (29) may be rewritten as follows.

Thus, the output signal V_OUTThe differential of (c) can be written as follows.

Compared with equation (31), it is apparent that the sensitivity can be increased for the capacitance case when the following condition is satisfied. When the first deformable part 21 is subjected toAt a first type of strain, C_1vAnd C_4vAll increase and/or C when the first deformable portion 21 is subjected to a second type of strain_1vAnd C_4vIs reduced. The first type of strain and the second type of strain refer to tension and compression, respectively, or compression and tension, respectively.

That is, in the case where all four branches are strain sensitive branches, the sensitivity of the device 10 with respect to the force exerted on the first deformable portion 21 will be further improved, as long as the electrical parameter of the first strain sensor 111 and the electrical parameter of the fourth strain sensor 114 change towards the same direction when the first deformable portion 21 is strained. The electrical parameter may be capacitance or resistance.

In a fifth embodiment, all four branches are strain sensitive branches and are symmetrical in a wheatstone branch structure. Thus, the sensitivity of the device to a force exerted on any other deformable portion will also follow the form of the sensitivity of the device to a force exerted on the first deformable portion 111.

The fourth strain sensor 114 in the present embodiment may be provided in the electronic apparatus in various ways. Referring to fig. 13, a cross-section of a portion of a housing of another electronic device including an apparatus for force sensing according to an embodiment of the present disclosure is shown. Based on the structure as shown in fig. 9, the fourth deformable portion is located at the fourth side wall 240 of the housing of the electronic device. That is, the fourth strain sensor 114 is attached to the fourth sidewall 240 at the third deformable portion 24. The fourth deformable portion 24 is not shown in fig. 13, similar to the other deformable portions. The first sidewall 210 and the fourth sidewall 240 may be parallel. Thus, when a force (indicated by either the open arrow) is applied on the first deformable portion 21 or the fourth deformable portion 24, the housing enclosing the electronic device may be compressed in the direction of the force and extended in a direction perpendicular to the direction of the force (where the strain of the side walls is indicated by the solid arrows). Thus, both the first deformable portion 21 and the fourth deformable portion 24 are subjected to stretching. Similarly, when an opposing force is applied on the first deformable portion 21 or the fourth deformable portion 24 (e.g., when the respective side wall is pulled or pushed upward), both the first deformable portion 21 and the fourth deformable portion 24 experience compression. With the same type of strain (i.e., tensile or compressive), the electrical parameters of both the first and

fourth strain sensors

111, 114 may change toward the same direction (i.e., increase or decrease). In this case, the above configuration will ensure that the electrical parameter of the first strain sensor 111 and the electrical parameter of the fourth strain sensor 114 change towards the same direction when any deformable portion is strained.

Note that the structure shown in fig. 13 is merely exemplary, and the fourth side wall 240 may be configured in other ways. For example, the first sidewall 210 and the fourth sidewall 240 may not be exactly parallel, but form an angle as long as both the first sidewall 210 and the fourth sidewall 240 are extended or compressed in one operation of the user. For another example, the fourth sidewall 240 may not be directly connected with one or both of the second sidewall 220 and the third sidewall 230, but connected via a component capable of conducting strain or another sidewall. Furthermore, the fourth strain sensor 114 may be arranged in other ways. For example, a fourth strain sensor 114 may be attached at the other side of the fourth sidewall 240. For another example, the fourth strain sensor 114 may be attached to the same sidewall as the first strain sensor 111, i.e., at the first sidewall 210.

In one embodiment, the first and

fourth strain sensors

111, 114 are attached to a first sidewall (or first member) 210, while the second and

third strain sensors

112, 113 are attached to a second sidewall (or second member) 220, as shown in fig. 14. The first sidewall 210 and the second sidewall 220 are connected to each other.

Although the sidewalls in fig. 5, 7, 9, 11, 13, and 14 are connected at a right angle, embodiments of the present disclosure are not limited thereto. The included angle between the connected side walls may alternatively be an acute angle or an obtuse angle. Referring to fig. 15 and 16, fig. 15 and 16 show structures that can be applied to the third and fourth embodiments, respectively.

In one embodiment, each strain transducer is a strain gaugeThe sensors are of the same type and each fixed resistor (or capacitor) in the other branches has the same resistance (or capacitance) equal to the electrical parameter of each strain sensor in the reference state. That is, for the first to fifth embodiments, R is present_1v＝R_2v＝R_3v＝R_4vAnd R₂＝R₃＝R₄Or C is_1v＝C_2v＝C_3v＝C_4vAnd C₂＝C₃＝C₄. The change in strain is assumed to be uniform in each deformable region (which means that the housing or component is able to conduct the strain well). In this case, considering a reference state (such as a non-strained state) of the force sensor, when compared with the case shown in fig. 3, the sensitivity is doubled in the first and second embodiments, tripled in the third and fourth embodiments, and quadrupled in the fifth embodiment.

As discussed above, the strain sensors in the device 10 may be resistive or capacitive elements. In one embodiment, at least one of the strain sensors is a strain gauge. The strain sensitive direction of the strain gauge may be aligned with the direction of compression or tension, such as the directions shown in fig. 5, 7, 9, 11, and 13-16. In another embodiment, at least one of the strain sensors is a capacitor. The capacitor may include two conductive members. The conductive members may be disposed parallel or substantially parallel to the surface of the corresponding deformable region. When the deformable region is thinned due to stretching, the distance between the two conductive members may be reduced, so that the capacitance of the strain sensor will increase. When the deformable region becomes thicker due to compression, the distance between the two conductive members may increase, so that the capacitance of the strain sensor will decrease. Alternatively, the conductive member may be disposed perpendicular or substantially perpendicular to the surface of the corresponding deformable region. When the deformable region is subjected to tension, the distance between the two conductive members may increase such that the capacitance of the strain sensor will decrease. When the deformable region is subjected to compression, the distance between the two conductive members may decrease, so that the capacitance of the strain sensor will increase. The strain sensor may be embodied in other forms, which are not further enumerated herein. Further, it should be understood that the strain sensors may not be all resistive or capacitive. For example, in the above embodiments, the first and second branches may be resistive, while the third and fourth branches may be capacitive.

Electronic devices are also provided according to the present disclosure. The electronic device comprises any of the above-described apparatus, a first deformable portion, a second deformable portion, and a hardware module. The analog signal output from the output terminal of the operational amplifier may be input into the hardware module, and the state of the hardware module changes in response to a signal state change. For example, the hardware module may be a switching transistor, wherein the switching transistor is turned on when the signal rises above a threshold and turned off when the signal falls below the threshold. For another example, the hardware module may be an analog-to-digital converter, wherein the analog-to-digital converter outputs a high level when the signal rises above the threshold and outputs a low level when the second signal falls below the threshold. In one embodiment, the hardware module may be a controller, processor, display, speaker, switch, indicator light, and the like. It should be understood that the hardware module may take other forms as long as the hardware module is capable of changing its state in accordance with the signal. In the case where the hardware module requires a digital signal as an input, the analog signal output from the output terminal of the operational amplifier needs to be first converted into a digital signal before being input into the hardware module.

The electronic devices may include mobile phones, watches, glasses, head-mounted display devices, ear-buds, keyboards, tablets, and the like. The deformable portion (e.g., any of the first deformable portion through the fourth deformable portion) may be a flexible display of a mobile phone, a wrist band of a watch, an elastic frame of eyeglasses, an elastic frame of a head-mounted display device, a metal or plastic housing of an ear bud headphone, a membrane of a keyboard, an elastic home key of a tablet computer, or the like. It should be understood that the electronic device and the deformable portion are not limited to the above, and specific examples are not listed here for the sake of brevity.

In practice, the means for force sensing may be configured based on the structure of the electronic device. For example, the electronic device is an earbud, the housing of the earbud includes a deformable cap (housing), and the user can operate the earbud by squeezing or pressing the deformable cap. In this case, the means for force sensing may be located inside the housing, and the strain sensor (e.g., any one of the first to fourth strain sensors) is attached to the inside of the deformable cap. The operational amplifier may be independent of or integrated on one or more Printed Circuit Boards (PCBs) surrounded by the housing. For another example, the electronic device is a foldable display device, a flexible display panel of the device is provided with a folding axis, and a user may open the device by opening the foldable display panel. In this case, the means for force sensing may be located within a foldable area of the display panel, and the strain sensor is attached to the inner side of the display screen at the foldable area. The operational amplifier may be independent of or integrated in one or more processors of the display device.

Embodiments of the present disclosure are described in a progressive manner, and each embodiment places emphasis on differences from other embodiments. Thus, for the same or similar parts, one embodiment may refer to the other embodiment. Since the electronic device disclosed in the embodiment corresponds to the apparatus disclosed in the embodiment, the description of the electronic device is simple, and the relevant part of the apparatus can be referred to.

Those of skill in the art may make or use the present disclosure in light of the description of the disclosed embodiments. Various modifications to these embodiments may be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for force sensing, the apparatus being applied to an electronic device, wherein the electronic device comprises a first deformable portion and a second deformable portion, and the apparatus comprises:

an operational amplifier;

a first branch connected between a first input terminal of the operational amplifier and a first terminal supplying a first voltage;

a second branch connected between the first input terminal and a second terminal supplying a second voltage, wherein the first voltage is different from the second voltage;

a third branch connected between a second input terminal of the operational amplifier and the first terminal; and

a fourth branch connected between the second input terminal and the second terminal;

wherein a first strain sensitive branch of the first, second, third, and fourth branches comprises a first strain sensor attached to the first deformable portion;

wherein a second strain sensitive branch of the first, second, third, and fourth branches comprises a second strain sensor attached to the second deformable portion;

wherein the second deformable portion is strained when the first deformable portion is strained.

2. The apparatus of claim 1, wherein,

the first strain sensitive branch is connected with the second strain sensitive branch at one of the first terminal, the second terminal, the first input terminal, or the second input terminal;

wherein the content of the first and second substances,

when the first deformable portion is subjected to a first type of strain, the electrical parameter of the first strain sensor increases and the electrical parameter of the second strain sensor decreases; and is

When the first deformable portion is subjected to a second type of strain, the electrical parameter of the first strain sensor decreases and the electrical parameter of the second strain sensor increases;

wherein the electrical parameter is resistance or capacitance; and is

Wherein the first type of strain is compressive and the second type of strain is tensile, or the first type of strain is tensile and the second type of strain is compressive.

3. The apparatus of claim 2, wherein,

the second deformable portion is subjected to the first type of strain when the first deformable region is subjected to the second type of strain; and is

The second deformable portion experiences the second type of strain when the first deformable region experiences the first type of strain.

4. The apparatus of claim 1, wherein,

the first strain sensitive branch is not connected with the second strain sensitive branch;

wherein the content of the first and second substances,

when the first deformable portion is subjected to a first type of strain, both an electrical parameter of the first strain sensor and an electrical parameter of the second strain sensor increase; and is

When the first deformable portion is subjected to a second type of strain, both the electrical parameter of the first strain sensor and the electrical parameter of the second strain sensor decrease; and is

Wherein the electrical parameter is resistance or capacitance; and is

5. The apparatus of claim 4, wherein,

the second deformable portion is subjected to the first type of strain when the first deformable region is subjected to the first type of strain; and is

The second deformable portion experiences the second type of strain when the first deformable region experiences the second type of strain.

6. The apparatus of claim 2 or 3, wherein the electronic device further comprises a third deformable portion,

wherein a third strain sensitive branch of the first, second, third, and fourth branches comprises a third strain sensor attached to the third deformable portion;

wherein the first strain sensitive branch is connected with the third strain sensitive branch at another of the first terminal, the second terminal, the first input terminal, or the second input terminal; and is

Wherein the content of the first and second substances,

the electrical parameter of the third strain sensor decreases when the first deformable portion experiences a first type of strain; and is

An electrical parameter of the third strain sensor increases when the first deformable portion experiences the second type of strain.

7. The apparatus of claim 6, wherein,

the third deformable portion experiences the first type of strain when the first deformable region experiences the second type of strain; and is

The third deformable portion experiences the second type of strain when the first deformable region experiences the first type of strain.

8. The apparatus of claim 2 or 3, wherein the electronic device further comprises a third deformable portion,

wherein the first strain sensitive branch is not connected with the third strain sensitive branch, and

wherein the content of the first and second substances,

an electrical parameter of the third strain sensor increases when the first deformable portion experiences the first type of strain; and is

An electrical parameter of the second strain sensor increases when the first deformable portion experiences the second type of strain.

9. The apparatus of claim 8, wherein,

the third deformable portion experiences the first type of strain when the first deformable region experiences the first type of strain; and is

The third deformable portion experiences the second type of strain when the first deformable region experiences the second type of strain.

10. The apparatus of claim 6, wherein the electronic device further comprises a fourth deformable portion,

a fourth strain sensitive branch of the first, second, third, and fourth branches comprises a fourth strain sensor attached to the fourth deformable portion; and is

Wherein the content of the first and second substances,

an electrical parameter of the fourth strain sensor increases when the first deformable portion experiences the first type of strain; and is

An electrical parameter of the fourth strain sensor decreases when the first deformable portion experiences the second type of strain.

11. The apparatus of claim 10, wherein,

the fourth deformable portion is subjected to the first type of strain when the first deformable region is subjected to the first type of strain; and is

The fourth deformable portion experiences the second type of strain when the first deformable region experiences the second type of strain.

12. The apparatus of any one of claims 2 to 11,

the electrical parameter is resistance; and is

Each of the first, second, third, and fourth strain sensors includes a strain gauge.

13. The apparatus of any one of claims 2 to 11,

the electrical parameter is capacitance;

each of the first, second, third, and fourth strain sensors includes a capacitor; and is

Wherein the content of the first and second substances,

the capacitance of the capacitor increases when the strain sensor is subjected to tension and decreases when the strain sensor is subjected to compression; or

The capacitance of the capacitor increases when the strain sensor is subjected to compression and decreases when the strain sensor is subjected to tension.

14. The apparatus of any one of claims 1 to 3 and 6 to 11,

the first deformable portion and the second deformable portion are located at a first sidewall and a second sidewall, respectively, of a housing of the electronic device;

the first and second sidewalls are connected to each other.

15. The apparatus of any one of claims 1, 4, and 5,

the first and second sidewalls are parallel to each other.

16. The apparatus of any one of claims 6, 7, 10, and 11,

the first, second, and third deformable portions are located at first, second, and third sidewalls, respectively, of a housing of the electronic device; and is

The first sidewall is connected with the second sidewall, and the first sidewall is connected with the third sidewall.

17. The apparatus of claim 8 or 9,

The first sidewall is connected to the second sidewall, and the first sidewall is parallel to the third sidewall.

18. The apparatus of claim 10 or 11,

the first, second, third, and fourth deformable portions are located at first, second, third, and fourth sidewalls, respectively, of a housing of the electronic device; and is

The first sidewall is connected to the second sidewall, the first sidewall is connected to the third sidewall, and the first sidewall is parallel to the fourth sidewall.

19. The apparatus according to claim 10 or 11,

the first deformable portion and the fourth deformable portion are located at a first sidewall;

the second deformable portion and the third deformable portion are located at a second sidewall; and is

The first side wall is connected with the second side wall.

20. An electronic device, comprising:

the device of any one of claims 1 to 19;

the first deformable portion;

the second deformable portion;

a hardware module configured to receive a signal output from an output terminal of the operational amplifier;

wherein the state of the hardware module changes in response to the signal state change.

21. The electronic device of claim 20, wherein the hardware module comprises at least one of: a processor, a controller, a display, a speaker, a switch, or an indicator light.

22. The electronic device of claim 20, the electronic device comprising at least one of: a mobile phone, a watch, glasses, a head-mounted display device, an ear-bud headphone, a keyboard, or a tablet.