Pressure detection mechanism and electronic device

Abstract

The present invention discloses a pressure detection mechanism and an electronic device. The pressure detection mechanism includes a pressure detection main body, a magnetic component, a planar diaphragm unit and a sound source. The pressure detection main body forms a sound shielding cavity and an opening communicating with the sound shielding cavity. The magnetic component is arranged on the pressure detection main body. The planar diaphragm unit is arranged on the pressure detection main body and is sealed at the opening. The planar diaphragm unit is in the magnetic field of the magnetic component. The sound source outputs a sound signal to excite the planar diaphragm unit to generate vibration. When the planar diaphragm unit generates vibration according to the sound signal, it cuts the magnetic induction lines of the magnetic component to output a corresponding induced current. The above solution solves the technical problem of the low detection accuracy of the existing pressure detection mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure detection, and particularly to a pressure detection mechanism and an electronic device. Background Art

[0002] Pressure detection mechanisms are widely used in electronic devices. For example, a pressure detection mechanism is used to detect the pressure of a user's press as an input to control the electronic device, or is applied to wearable devices to measure the tightness of the user's wearing. However, existing pressure detection mechanisms generally measure pressure based on the piezoresistive effect, and their detection accuracy is relatively low. Summary of the Invention

[0003] The main objective of the present invention is to propose a pressure detection mechanism, aiming to solve the technical problem of relatively low detection accuracy of existing pressure detection mechanisms.

[0004] To achieve the above objective, the present invention proposes a pressure detection mechanism, which includes:

[0005] A pressure detection main body, which forms an acoustic shielding cavity and an opening communicating with the acoustic shielding cavity;

[0006] A magnetic component, which is arranged on the pressure detection main body;

[0007] A planar diaphragm unit, which is arranged on the pressure detection main body and is sealed at the opening, and the planar diaphragm unit is within the magnetic field of the magnetic component; and

[0008] A sound source, which is arranged in the acoustic shielding cavity and is used to output a sound signal to excite the planar diaphragm unit to generate vibration;

[0009] The planar diaphragm unit is used to cut the magnetic induction lines of the magnetic component to output a corresponding induced current when generating vibration according to the sound signal.

[0010] Optionally, the planar diaphragm unit includes a pressing film and an electromagnetic coil. The electromagnetic coil is arranged on the pressing film. When the pressing film vibrates according to the sound signal, the electromagnetic coil cuts the magnetic induction lines of the magnetic component to output a corresponding induced current.

[0011] Optionally, the electromagnetic coil is in a planar spiral shape.

[0012] Optionally, the material of the acoustic shielding cavity is a sound insulation and shielding material.

[0013] Optionally, the magnetic component is a permanent magnet or an electromagnet.

[0014] Optionally, the magnetic component is a substrate, the substrate is disposed in the sound shielding cavity, and the sound source is disposed on the substrate and accommodated in the sound shielding cavity; and / or,

[0015] The sound shielding cavity is further provided with an installation opening, and the substrate is sealed at the installation opening of the sound shielding cavity.

[0016] Optionally, the sound shielding cavity is cylindrical and has two opposite tube openings, and the two tube openings respectively correspond to the first port and the second port.

[0017] Optionally, the sound shielding cavity is filled with an inert gas.

[0018] To achieve the above object, the present invention further provides an electronic device, and the electronic device includes the pressure detection mechanism as described above.

[0019] Optionally, the electronic device further includes a control circuit, an operational amplifier circuit, and a sound comparison circuit. The control signal output end of the control circuit is connected to the input end of the pressure detection mechanism, the feedback end of the control circuit is connected to the output end of the sound comparison circuit, and the reference signal output end of the control circuit is connected to the reference signal input end of the sound comparison circuit; the input end of the operational amplifier circuit is connected to the output end of the pressure detection mechanism, and the output end of the operational amplifier circuit is connected to the input end of the sound comparison circuit;

[0020] The control circuit is configured to output a control signal to control the sound source of the pressure detection mechanism to emit a sound signal with a fixed frequency;

[0021] The planar diaphragm unit of the pressure detection mechanism is configured to generate a feedback current signal according to the sound signal;

[0022] The operational amplifier circuit is configured to amplify the current signal;

[0023] The sound comparison circuit is configured to compare the amplified current signal with a preset reference signal and output the comparison result to the control circuit;

[0024] The control circuit is configured to determine the magnitude of the pressing force borne by the pressing film of the pressure detection mechanism according to the comparison result.

[0025] The technical solution of the present invention's pressure detection mechanism includes a pressure detection main body, a magnetic component, a planar diaphragm unit, and a sound source. The pressure detection main body forms a sound shielding cavity and an opening communicating with the sound shielding cavity. The magnetic component is arranged on the pressure detection main body. The planar diaphragm unit is arranged on the pressure detection main body and is sealed at the opening. The planar diaphragm unit is in the magnetic field of the magnetic component. The sound source outputs a sound signal to transmit vibration to the planar diaphragm unit, exciting the planar diaphragm unit to generate vibration. When the planar diaphragm unit generates vibration according to the sound signal, it cuts the magnetic induction lines of the magnetic component to output a corresponding induced current. Through the above process, rather than by measuring the piezoresistive effect, the minute deformation of the planar diaphragm unit can be detected, so as to improve the sensitivity of the diaphragm, thereby solving the technical problem of the low detection accuracy of the existing pressure detection mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0027] Figure 1 It is a schematic structural diagram of the pressure detection mechanism of the present invention;

[0028] Figure 2 It is a schematic module diagram of the electronic device of the present invention;

[0029] Figure 3 It is a waveform diagram of the induced electromotive force voltage and time when there is no pressure in the pressure detection mechanism of the present invention;

[0030] Figure 4 It is a waveform diagram of the induced electromotive force voltage and time when there is pressure in the pressure detection mechanism of the present invention.

[0031] The realization of the object, functional features, and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one of such features.

[0033] The present invention provides a pressure detection mechanism, aiming to solve the technical problem of low detection accuracy of the pressure detection mechanism.

[0034] In one embodiment, if Figure 1 As shown, the pressure detection mechanism includes a pressure detection body, a magnetic component 20, a planar diaphragm unit and a sound source 30. The pressure detection body 10 is formed with a sound shielding cavity and an opening connected to the sound shielding cavity. The magnetic component 20 is arranged on the pressure detection body 10. The planar diaphragm unit is arranged on the pressure detection body 10 and sealed in the opening. The planar diaphragm unit is in the magnetic field of the magnetic component 20. The sound source 30 is arranged in the sound shielding cavity.

[0035] Among them, since the sound can cause the resonance of the planar diaphragm unit, the planar diaphragm unit cuts the magnetic flux lines of the magnetic component 20 when it vibrates to generate an induced current. At this time, the sound source 30 outputs a sound signal to excite the planar diaphragm unit to vibrate, and when the planar diaphragm unit vibrates according to the sound signal, it cuts the magnetic flux lines of the magnetic component 20 to output the corresponding induced current. At this time, if there is a pressing force on the planar diaphragm unit, the amplitude of the planar diaphragm unit will decrease, thereby changing the magnitude of the induced current, so as to measure the pressing force. In the above measurement process, since the planar diaphragm unit can be deformed to a certain extent under a relatively small pressing force, thereby changing the magnitude of the output induced current, that is, the diaphragm can measure a smaller pressing force, therefore, the detection accuracy of the pressure detection mechanism can be improved through the above structure. In addition, since the form of sound signal output detection feedback is adopted at this time, the pressing force at this time can also be determined according to the induced current of the planar diaphragm unit vibrated by the sound signal when the pressing force borne by the planar diaphragm unit remains unchanged, so that the pressure detection mechanism of the present application can also accurately measure the static pressing force borne by the pressure detection mechanism at this time.

[0036] It should be noted that in the exemplary technology, there are ceramic pressure detection mechanisms, diffused silicon pressure detection mechanisms, sapphire pressure detection mechanisms, and piezoresistive pressure detection mechanisms. The following is a brief introduction to these pressure detection mechanisms:

[0037] 1) Piezoelectric pressure detection mechanism: The piezoelectric effect is the main working principle of the pressure detection mechanism. The pressure detection mechanism cannot be used for static measurement, because the charge after the external force is applied can only be saved when the circuit has infinite input impedance. The actual situation is not like this, so this determines that the pressure detection mechanism can only measure dynamic stress.

[0038] 2) Ceramic pressure detection mechanism: Based on the piezoresistive effect, the pressure directly acts on the front surface of the ceramic diaphragm, causing the diaphragm to produce a slight deformation. The thick film resistors are printed on the back of the ceramic diaphragm and connected into a Wheatstone bridge. Due to the piezoresistive effect of the piezoresistors, the bridge generates a voltage signal that is highly linear with the pressure and also proportional to the excitation voltage. The standard signal is calibrated as 2.0 / 3.0 / 3.3 mv / v, etc. according to different pressure ranges and can be compatible with strain gauges.

[0039] 3) Diffused silicon pressure detection mechanism: The working principle of the diffused silicon pressure detection mechanism is also based on the piezoresistive effect. Using the piezoresistive effect principle, the pressure of the measured medium directly acts on the diaphragm (stainless steel or ceramic) of the pressure detection mechanism, causing the diaphragm to produce a micro-displacement proportional to the medium pressure, changing the resistance value of the sensor. An electronic circuit is used to detect this change and convert it into a standard measurement signal corresponding to this pressure.

[0040] 4) Sapphire pressure detection mechanism: Using the strain resistance working principle, silicon-sapphire is used as the semiconductor sensitive element, which has unparalleled measurement characteristics. Therefore, the semiconductor sensitive element made of silicon-sapphire is insensitive to temperature changes and has good working characteristics even under high-temperature conditions; sapphire has extremely strong radiation resistance; in addition, the silicon-sapphire semiconductor sensitive element has no p-n drift.

[0041] 5) Piezoresistive pressure detection mechanism: The resistance strain gauge is one of the main components of the piezoresistive pressure detection mechanism. The working principle of the metal resistance strain gauge is the phenomenon that the strain resistance adsorbed on the matrix material changes its resistance value with mechanical deformation, commonly known as the resistance strain effect.

[0042] From the above, it can be seen that the detection accuracy of the above pressure detection mechanism is lower than the scheme proposed in the present application. The reason is that the present application proposes a pressure measurement method with a new principle, in which the plane diaphragm unit resonates when the sound signal vibrates, and the plane diaphragm unit cuts the magnetic flux lines of the magnetic component 20 to generate an induced current when the plane diaphragm unit vibrates. At this time, the sound source 30 outputs a sound signal to excite the plane diaphragm unit to vibrate, and when the plane diaphragm unit vibrates according to the sound signal, it cuts the magnetic flux lines of the magnetic component 20 to output the corresponding induced current. Therefore, the plane diaphragm unit of the pressure detection mechanism can be deformed to a certain extent under a relatively small pressing force, thereby changing the output induced current size, that is, the diaphragm can measure a smaller pressing force, so the detection accuracy of the pressure detection mechanism can be improved by the above structure. In addition, since the form of sound signal output detection feedback is adopted at this time, the pressing force at this time can also be determined according to the induced current of the plane diaphragm unit vibrated by the sound signal when the pressing force size of the plane diaphragm unit remains unchanged, so that the pressure detection mechanism of the present application can also accurately determine the static pressing force borne by the pressure detection mechanism at this time. In addition, the raw materials used in this solution are simple and easy to obtain, which can reduce production and manufacturing costs and has great industrial value.

[0043] Optionally, the sound source 30 is a speaker.

[0044] Alternatively, if Figure 1 As shown, the planar diaphragm unit includes a pressing film 501 and an electromagnetic coil 502, and the electromagnetic coil 502 is arranged on the pressing film 501. At this time, the electromagnetic coil 502 is deformed with the vibration of the sound signal of the pressing film 501, and then cuts the magnetic induction line movement, so as to detect the pressing force applied to the pressing film 501, thereby improving the detection accuracy of the pressure detection mechanism. Since it is a feedback detection at this time, even if the pressure at this time is static, the vibration of the sound signal can still change the deformation of the planar diaphragm unit, so that the electromagnetic coil 502 has an induced current output, so that the static pressing force value can be measured.

[0045] Optionally, the electromagnetic coil 502 is in a planar spiral shape.

[0046] When the electromagnetic coil 502 is in a planar spiral shape, the induced current it outputs can more comprehensively reflect the change in pressure value and can comprehensively detect the pressure change in the plane where the electromagnetic coil 502 is located, avoiding the situation where the pressure change at a single position cannot be detected, thereby improving the detection accuracy.

[0047] Optionally, the sound shielding cavity is made of a sound-insulating material, such as a steel plate, a lead plate, a concrete wall, a brick wall, etc., so as to reduce the impact of the pressure detection mechanism on the external environment during operation.

[0048] Optionally, the magnetic component 20 is a permanent magnet. By providing a permanent magnet, the sealing effect of the pressure detection mechanism can be ensured, eliminating the need for additional holes to access power, thereby reducing the likelihood of interference to the planar diaphragm unit and improving the detection accuracy.

[0049] Optionally, the magnetic component 20 is a substrate, the sound source 30 is mounted on the substrate, the substrate is disposed in a sound shielding cavity, and the sound source 30 is disposed on the substrate and accommodated in the sound shielding cavity. With the above structure, the position of the sound source 30 can be fixed, ensuring that the vibration amplitudes of the sound signals applied to the planar diaphragm unit by the sound source 30 are consistent. As a result, when no pressing force is applied to the planar diaphragm unit, the measured induced current remains consistent, improving the detection accuracy.

[0050] Optionally, the magnetic component 20 is a substrate, and the sound shielding cavity is further provided with a mounting opening, and the substrate is sealed at the mounting opening of the sound shielding cavity. Thereby, the position of the sound source 30 can be fixed, ensuring that the vibration amplitudes of the sound signals applied to the planar diaphragm unit by the sound source 30 are consistent. As a result, when no pressing force is applied to the planar diaphragm unit, the measured induced current remains consistent, improving the detection accuracy.

[0051] Optionally, the magnetic component 20 is an electromagnet. With an electromagnet, the magnetic field attenuation of the permanent magnet can be avoided, preventing detection failure.

[0052] Optionally, the sound shielding cavity is cylindrical.

[0053] When the sound shielding cavity is cylindrical, it is convenient for the installation and vibration of the planar diaphragm unit, improving the pressure-bearing capacity of the planar diaphragm unit.

[0054] Optionally, one end of the cylinder is an opening and the other end is a mounting opening, which can ensure the structural stability of the pressure detection mechanism and leave a certain vibration space for the planar diaphragm unit to vibrate along with the sound signal and the pressing force, improving the measurement accuracy.

[0055] Optionally, the sound shielding cavity is filled with an inert gas. By measuring with an inert gas, the loss of sound signal transmission can be reduced, further improving the detection accuracy and precision.

[0056] The present invention also provides an electronic device, as Figure 2 shown, the electronic device includes the pressure detection mechanism as described above.

[0057] Among them, the electronic device can be a wearable device or a smart home device such as a bracelet, earphone, VR device, etc. that uses the pressure detection mechanism for pressure measurement. It should be noted that since the electronic device of the present invention includes all the embodiments of the above pressure detection mechanism, the electronic device of the present invention has all the beneficial effects of the above pressure detection mechanism, which will not be elaborated here.

[0058] Optionally, the electronic device further includes a control circuit 80, an operational amplifier circuit 70, and a sound comparison circuit 60. The control signal output terminal of the control circuit 80 is connected to the input terminal of the pressure detection mechanism. The feedback terminal of the control circuit 80 is connected to the output terminal of the sound comparison circuit 60. The reference signal output terminal of the control circuit 80 is connected to the reference signal input terminal of the sound comparison circuit 60. The input terminal of the operational amplifier circuit 70 is connected to the output terminal 503 of the pressure detection mechanism. The output terminal of the operational amplifier circuit 70 is connected to the input terminal of the sound comparison circuit 60.

[0059] Wherein, the control circuit 80 outputs a control signal to control the sound source 30 of the pressure detection mechanism to generate a sound oscillation. When the planar diaphragm unit of the pressure detection mechanism vibrates according to the sound signal, it cuts the magnetic induction lines of the magnet of the pressure detection mechanism to output a corresponding induced current, and the induced current is recorded as the feedback current signal. The operational amplifier circuit 70 amplifies the current signal. The sound comparison circuit 60 compares the amplified current signal with a preset reference signal and outputs the comparison result to the control circuit 80. The control circuit 80 determines the magnitude of the pressing force borne by the pressure detection mechanism according to the comparison result. It should be noted that when the detection signal of the pressure detection mechanism is a sound signal with a fixed frequency, different current signals have corresponding pressing force detection magnitudes, and their corresponding relationships can be pre-stored in the control circuit after being determined through laboratory tests and directly called during detection. In addition, when the fixed frequency of the sound signal changes, the corresponding relationship between the current signal and the pressing force will also change accordingly.

[0060] When the sound source 30 starts to work, the vibration frequency waveform of the planar diaphragm unit is as follows, that is, the received source frequency without any interference will increase and finally reach the resonant frequency. In this process, the time to reach resonance is related to the filling air pressure and the diaphragm material and needs specific experimental calculation. Since the induced electromotive force E = BLV, when B and L are constant, E (V) is proportional to V, so the waveform of the vibration frequency is consistent with the waveform of E, as Figure 3 shown. We can know that it is not pressed currently by collecting the induced electromotive force voltage.

[0061] When the button is pressed. As Figure 4 shown, if such a fluctuation is detected, it means the button is pressed. The greater the force when pressing it instantaneously, the deeper A will sink. If this force is maintained, the greater the force, the smaller the slope of B.

[0062] In the above solution, the pressure detection mechanism has two working modes:

[0063] 1. Non-pressure-sensitive mode:

[0064] The control circuit 80 sends out oscillations of a fixed frequency to the sound source 30 (speaker). This oscillation excites the planar diaphragm unit to generate sound, producing the effect of a speaker. In essence, the oscillation of the bottom speaker causes the oscillation of the upper membrane, resulting in resonance together. At this time, the substrate is a magnet. When the planar diaphragm unit oscillates, the electromagnetic coil on it cuts the magnetic induction lines, generating an induced current. The induced current is transmitted into the sound comparison circuit 60 through the operational amplifier circuit 70, so that the voltage generated by pressing on the amplitude of the pressing membrane 501 can be further read to perform loudness correction.

[0065] 2. Pressure-sensitive mode

[0066] When an object presses on the pressing membrane 501, due to the deformation of the pressing membrane 501, the resonance effect will weaken, and as the pressing pressure increases, the resonance effect will decrease accordingly. By comparing the attenuation of the resonance amplitude through the sound comparison circuit 60, the degree of the pressing force can be known.

[0067] Through the above solution, not only can the detection accuracy of the pressure detection mechanism be improved, but also loudness correction and dynamic and static detection of pressure can be achieved, greatly increasing the functions of the pressure-sensitive detector.

[0068] Optionally, the control circuit 80 can be an MCU, the operational amplifier circuit 70 can be an operational amplifier, and the sound comparison circuit 60 is a sound comparator. Details are not described here again.

[0069] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A pressure detection mechanism, characterized in that, the pressure detection mechanism includes: a pressure detection main body, the pressure detection main body forming a sound shielding cavity and an opening communicating with the sound shielding cavity; a magnetic component, provided on the pressure detection main body; a planar diaphragm unit, provided on the pressure detection main body and sealed at the opening, the planar diaphragm unit being within the magnetic field of the magnetic component; and a sound source, provided in the sound shielding cavity for outputting a sound signal to excite the planar diaphragm unit to vibrate; the planar diaphragm unit, when vibrating according to the sound signal, cutting the magnetic induction lines of the magnetic component to output a corresponding induced current; the planar diaphragm unit includes a pressing film and an electromagnetic coil, the electromagnetic coil being provided on the pressing film, when the pressing film vibrates according to the sound signal, the electromagnetic coil cutting the magnetic induction lines of the magnetic component to output a corresponding induced current, the sound source outputting a sound signal to excite the planar diaphragm unit to vibrate, when the planar diaphragm unit vibrates according to the sound signal, cutting the magnetic induction lines of the magnetic component to output a corresponding induced current, if there is a pressing force on the planar diaphragm unit, the amplitude of the planar diaphragm unit will decrease, thereby changing the magnitude of the induced current, so as to measure the pressing force.

2. The pressure detection mechanism according to claim 1, characterized in that, the electromagnetic coil is in a planar spiral shape.

3. The pressure detection mechanism according to claim 1, characterized in that, the material of the sound shielding cavity is a sound insulation material.

4. The pressure detection mechanism according to claim 1, characterized in that, the magnetic component is a permanent magnet or an electromagnet.

5. The pressure detection mechanism according to claim 4, characterized in that, the magnetic component is a substrate, the substrate being provided in the sound shielding cavity, the sound source being provided on the substrate and accommodated in the sound shielding cavity; and / or, the sound shielding cavity is further provided with an installation opening, the substrate being sealed at the installation opening of the sound shielding cavity.

6. The pressure detection mechanism according to claim 1, characterized in that, the sound shielding cavity is cylindrical.

7. The pressure detection mechanism according to any one of claims 1-6, characterized in that, the sound shielding cavity is filled with an inert gas.

8. An electronic device, characterized in that, the electronic device includes the pressure detection mechanism according to any one of claims 1-7.

9. The electronic device according to claim 8, characterized in that, the electronic device further includes a control circuit, an operational amplifier circuit and a sound comparison circuit, the control signal output end of the control circuit being connected to the input end of the pressure detection mechanism, the feedback end of the control circuit being connected to the output end of the sound comparison circuit, the reference signal output end of the control circuit being connected to the reference signal input end of the sound comparison circuit; the input end of the operational amplifier circuit being connected to the output end of the pressure detection mechanism, the output end of the operational amplifier circuit being connected to the input end of the sound comparison circuit; The control circuit is configured to output a control signal to control the sound source of the pressure detection mechanism to emit a sound signal with a fixed frequency; The planar diaphragm unit of the pressure detection mechanism is configured to generate a feedback current signal according to the sound signal; The operational amplifier circuit is configured to amplify the current signal; The sound comparison circuit is configured to compare the amplified current signal with a preset reference signal and output the comparison result to the control circuit; The control circuit is configured to determine the magnitude of the pressing force borne by the pressing film of the pressure detection mechanism according to the comparison result.

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