CN112951977A

Movatterモバイル変換

Info

Publication number: CN112951977A
Application number: CN202110138073.7A
Authority: CN
Inventors: 宋军; 渡边嘉二郎
Original assignee: Suzhou Sensi Microelectronics Technology Co Ltd
Current assignee: Suzhou Sensi Microelectronics Technology Co Ltd
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2021-06-11

Abstract

The invention provides a piezoelectric element and an automobile integrated electronic device, based on the feedback cycle performance of the piezoelectric element, thereby having the multi-input multi-output characteristic, the formed automobile integrated electronic device comprises: multiple-input-multiple-output actuators, sensors, speakers, wireless transmitter power supplies, multivariable sensor systems, and integrated electronic systems that integrate speakers and multivariable sensor systems; the sensor includes: vibration sensors, acoustic sensors, and temperature sensors. Has the advantages that: by providing this integrated electronic device in the space portion of the roof lining of the automobile, a low-power and lightweight speaker system and a device for simultaneously measuring the physical quantity while using the output of one piezoelectric element in a frequency division manner are realized, whereby the number of components and the harness can be reduced, and further, reliability and cost can be improved.

Description

Piezoelectric element and automobile integrated electronic device

Technical Field

The invention belongs to the technical field of piezoelectric elements, and particularly relates to a piezoelectric element and an automobile integrated electronic device.

Background

A vehicle is equipped with sensors and acoustic devices for suspension control, safety, a human-machine interface, an air conditioner, and the like, and is equipped with other components through wiring. The reliability is reduced due to the increase in the number of components, and the cost of components and the labor cost for assembling and installing the wire harness are increased and the cost is increased. In addition, the conventional car audio uses a dynamic speaker, which has a weight of 2.5kg, uses 100W of electric power, and wastes energy.

Reduction of complex wiring harness by mounting many sensors and reduction of weight of automobile

At present, a large number of sensors and acoustic devices are generally required to be mounted in a vehicle. A plurality of independent sensors need to be used for each sensor measurement target. For example, a vibration sensor for detecting vibration, a thermometer for detecting temperature, an acceleration sensor for collision for detecting collision, a theft sensing sensor for detecting theft, and the like. The acoustic device includes a microphone that captures voice, a speaker that generates sound, and the like.

Since the sensor and the acoustic device are independent devices and are respectively mounted through wiring, on one hand, a plurality of sensors and acoustic devices need to be purchased and installed, and the management and maintenance costs are increased. In addition, the wire harness for connecting the sensor and the acoustic device is complicated and long, and thus, the complexity of the assembly of the device increases, increasing the cost of manufacturing the automobile.

In particular, two to five speakers are generally required, and particularly, in the case of a speaker disposed at a door position, it takes much labor and time to set and arrange a wire harness. Further, since the dynamic speaker is used, the total weight is heavy, generally 2.5kg, and the power used is also large, 100W, which is not favorable for achieving weight reduction and power saving of fuel efficiency.

To sum up, because the number of the sensors and the acoustic equipment arranged in the automobile is more and the sensors and the acoustic equipment are arranged independently, the overall reliability is reduced, the equipment cost and the wiring complexity are increased, and the labor cost is increased. In addition, the conventional car audio uses a dynamic speaker, which has a weight of 2.5kg and a power consumption of 100W, and thus causes energy waste.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a piezoelectric element and an automobile integrated electronic device, which can effectively solve the problems.

The technical scheme adopted by the invention is as follows:

the invention provides a piezoelectric element, which has feedback cycle performance so as to have multi-input multi-output characteristics, and specifically comprises:

taking any physical quantity of force, displacement, charge, voltage and current or temperature as the input of the piezoelectric element; the piezoelectric element outputs any one of a physical quantity of force, displacement, electric charge, voltage, and current, or temperature.

The present invention also provides a piezoelectric element based automotive integrated electronics device comprising a multiple input-multiple output actuator, a sensor, a speaker, a wireless transmitter power supply, a multivariable sensor system, and an integrated electronics system integrating the speaker and multivariable sensor system.

Preferably, the speaker includes: a piezoelectric element (1), a vibration plate (13), a thin rod (12), a mass block (1-1), and an audio function unit (15); the audio function part (15) comprises an audio source (15-1), an audio amplifier (15-2) and a step-up transformer (15-3);

the mass block (1-1) for realizing the stable movement of the piezoelectric element (1) is arranged at the periphery of a negative electrode plate of the piezoelectric element (1); one end of the thin rod (12) is connected with the central part of the piezoelectric element (1) with the maximum vibration amplitude; the other end of the thin rod (12) is connected with the central part of the vibrating plate (13);

the sound source (15-1) is connected to the piezoelectric element (1) after passing through the audio amplifier (15-2) and the booster transformer (15-3) in sequence;

the working process is as follows:

the sound source (15-1) generates a sound signal in a voltage form, the sound signal in the voltage form is amplified by the audio amplifier (15-2), and is boosted by the booster transformer (15-3) to obtain a boosted sound signal in the voltage form, and the boosted sound signal is transmitted to the piezoelectric element (1);

the piezoelectric element (1) converts the boosted sound signal in the voltage form into a corresponding vibration displacement signal, and transmits the vibration displacement signal to the vibration plate (13) through the thin rod (12), so that the vibration plate (13) vibrates to emit amplified sound, and further a loudspeaker function is realized;

wherein the audio amplifier (15-2) is impedance matched to the piezoelectric element (1); the mechanical vibration of the maximum displacement vibration surface of the piezoelectric element (1) and the mechanical vibration of the vibration plate (13) realize mechanical impedance matching, so that the vibration of a sound source (15-1) is efficiently converted into the vibration of the vibration plate (13).

Preferably, the sensor comprises: vibration sensors, acoustic sensors, and temperature sensors;

the vibration sensor includes: the device comprises a piezoelectric element (1), a signal amplifier (16-1), a vibration filter and a vibration sensing end;

the vibration force sensed by the vibration sensing end or the displacement of vibration generated by applying the vibration force is filtered by the vibration filter to form vibration waves of a first frequency band, and the vibration waves are amplified by the signal amplifier (16-1) and transmitted to the piezoelectric element (1);

the piezoelectric element (1) converts the sensed vibration wave into a voltage signal and outputs the voltage signal, so that the function of a vibration sensor for converting vibration into voltage is realized;

the acoustic sensor includes: the device comprises a piezoelectric element (1), a signal amplifier (16-1), an audio filter and a sound sensing end; the sound sensing end senses sound pressure, the sound pressure is filtered by the audio filter, amplified by the signal amplifier (16-1) and transmitted to the piezoelectric element (1);

the pressure-receiving surface of the piezoelectric element (1) converts the sensed sound pressure into force, and the force is used as the input of the piezoelectric element (1); the piezoelectric element (1) converts force into a voltage signal and outputs the voltage signal, so that the sound function of converting sound vibration into voltage is realized;

the temperature sensor includes: the temperature sensor comprises a piezoelectric element (1), a signal amplifier (16-1), a temperature filter and a temperature sensing end; the temperature sensing end senses temperature variation, the temperature variation is filtered by the temperature filter, amplified by the signal amplifier (16-1) and transmitted to the piezoelectric element (1);

the piezoelectric element (1) converts the temperature variation into a voltage signal and outputs the voltage signal, so that the function of the temperature sensor converting the temperature variation into voltage is realized.

Preferably, the wireless transmitter power supply comprises a piezoelectric element (1);

the piezoelectric element (1) is arranged in an automobile; when a large collision occurs to the automobile, vibration generated by the collision is used as input of the piezoelectric element (1), and the piezoelectric element (1) converts the vibration generated by the collision into electric energy to be used as a power supply and a signal source of the wireless transmitter.

Preferably, the multivariate sensor system is defined as: the functions of vibration sensing, sound sensing and temperature sensing are realized simultaneously by using frequency division and through one piezoelectric element;

specifically, the multivariable sensor system comprises: the device comprises a piezoelectric element (1), a signal amplifier (16-1), a filter (16-2), a vibration sensing end, a sound sensing end and a temperature sensing end;

wherein the filter (16-2) comprises an audio filtering unit, a vibration filtering unit and a temperature filtering unit;

the vibration sensing end is connected to the input end of the signal amplifier (16-1) through the vibration filtering unit; the sound sensing end is connected to the input end of the signal amplifier (16-1) through the audio filtering unit; the temperature sensing end is connected to the input end of the signal amplifier (16-1) through the temperature filtering unit; the output end of the signal amplifier (16-1) is connected to the piezoelectric element (1);

the working principle is as follows:

the sound, vibration and temperature change frequency bands are different, and the audio filtering unit filters the sensed audio signal to the 1 st frequency band; the vibration filtering unit filters the sensed vibration signal to a2 nd frequency band; the temperature filtering unit filters the sensed temperature change signal to a 3 rd frequency band; the 1 st frequency band, the 2 nd frequency band and the 3 rd frequency band are different from each other, so that the signals are amplified by the signal amplifier (16-1) and then act on the piezoelectric element (1); the piezoelectric element (1) converts the sensed signal frequency band into corresponding output.

Preferably, the integrated electronic system integrating the speaker and the multivariate sensor system is as follows: switching one piezoelectric element to a speaker function and a multivariable sensor system function in a time division manner; namely: the multivariable sensor system and the loudspeaker share the same piezoelectric element.

Preferably, the integrated electronic system integrating a speaker and a multivariable sensor system comprises:

the piezoelectric sensor comprises a piezoelectric element (1), a loudspeaker module, a multivariable sensor system module and a selector switch; wherein the change-over switch comprises a first change-over switch (14-1) and a second change-over switch (14-2) which are linked;

the speaker module includes: the device comprises a vibrating plate (13), a thin rod (12), a mass block (1-1), a sound source (15-1), an audio amplifier (15-2) and a booster transformer (15-3);

the multivariable sensor system module comprises: the device comprises a signal amplifier (16-1), a filter (16-2), a vibration sensing end, a sound sensing end and a temperature sensing end;

the piezoelectric element (1) passes through the second selector switch (14-2) and then is sequentially connected with the booster transformer (15-3), the audio amplifier (15-2) and the sound source (15-1); the input end of the sound source (15-1) is provided with the first change-over switch (14-1); the first change-over switch (14-1) and the second change-over switch (14-2) are linked;

the filter (16-2) is connected to the second switch (14-2) through the signal amplifier (16-1).

Preferably, the integrated electronic system integrating a speaker and a multivariable sensor system comprises: a speaker unit and a multivariable sensor system unit;

the loudspeaker unit comprises a vibrating plate (13), a thin rod (12), a first piezoelectric element, a mass block (1-1), a sound source (15-1), an audio amplifier (15-2) and a booster transformer (15-3);

the multivariable sensor system unit comprises: the wireless transmitter comprises a second piezoelectric element, a wireless transmitter power supply, a signal amplifier (16-1), a filter (16-2), a vibration sensing end, a sound sensing end and a temperature sensing end;

wherein: the mass block (1-1) for realizing the stabilization of the first piezoelectric element is arranged at the periphery of the negative electrode plate of the first piezoelectric element; one end of the thin rod (12) is connected with the central part of the first piezoelectric element with the maximum vibration amplitude; the other end of the thin rod (12) is connected with the central part of the first piezoelectric element; the first piezoelectric element is sequentially connected with the boosting transformer (15-3), the audio amplifier (15-2) and the sound source (15-1);

the second piezoelectric element is connected to the filter (16-2) after passing through the signal amplifier (16-1); the power taking position of the wireless transmitter power supply is the position from the second piezoelectric element to the upper surface of the cable of the signal amplifier (16-1);

the first piezoelectric element and the second piezoelectric element are made in one piece.

Preferably, the piezoelectric element unit of the automotive integrated electronic device is provided in a roof lining space of an automobile.

The piezoelectric element and the automobile integrated electronic device provided by the invention have the following advantages:

by providing the speaker and the sensor in the space portion of the roof lining of the automobile, a low-power and lightweight speaker system and a device for simultaneously measuring the physical quantity while using the output of one piezoelectric element in a frequency division manner are realized, whereby the number of components and the harness can be reduced, and further, the reliability and the cost can be improved.

Drawings

Fig. 1 is an external view of a piezoelectric element according to the present invention.

FIG. 2 is a schematic diagram of the operation of a piezoelectric element when a voltage is applied;

FIG. 3 is a schematic diagram of a piezoelectric element under stress

FIG. 4 is a schematic view of a piezoelectric element during heating and cooling

FIG. 5 is a schematic view showing the application of an AC voltage to a piezoelectric element

FIG. 6 is a diagram of a frame line for voltage-to-displacement transition in a piezoelectric element;

FIG. 7 is a block diagram of the force to voltage conversion in a piezoelectric element;

FIG. 8 is a diagram of a frame line for voltage-to-displacement transition in a piezoelectric element;

FIG. 9 is a block diagram of the force to voltage conversion in a piezoelectric element;

FIG. 10 is a schematic diagram of an integrated automotive electronics device incorporating a piezoelectric element in accordance with the present invention;

FIG. 11 is a schematic diagram of an integrated electronic device for an automobile with two integrated piezoelectric elements according to the present invention;

fig. 12 is a view showing the arrangement of the present invention between a roof lining and a body ceiling of an automobile.

Wherein:

1: a piezoelectric element; 1-1: a mass block;

2: a parallel plane piezoelectric material;

3: the silver coating coated on the surface of the piezoelectric material is a positive electrode;

4: the conductor is adhered with the piezoelectric material and is a negative electrode;

5: a conductor wire of a positive electrode;

6: a conductor line of the negative electrode;

7: a mode in which the piezoelectric element is deformed by applying a voltage to the conductor line to generate coulomb force;

8: a mode in which a force acts on the piezoelectric element to deform the piezoelectric element and a voltage is generated between the electrodes by utilizing a piezoelectric phenomenon;

9: a mode in which a voltage is generated by a pyroelectric effect generated by heating or cooling a piezoelectric element;

10: a mode in which an alternating current flows by applying an alternating voltage between both electrodes of the piezoelectric element;

11-1: converting the boxline graph from voltage to displacement; 11-2: a boxplot of the force to voltage transition;

12: a thin rod;

13: a vibrating plate;

14: a speaker condition and sensor switch; 14-1: a first changeover switch; 14-2: a second changeover switch;

15: an audio function section; 15-1: a sound source; 15-2: an audio amplifier; 15-3: a step-up transformer;

16: a sensor device; 16-1: a signal amplifier; 16-2: a filter;

17: two piezoelectric element integrated devices.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a piezoelectric element, which is a piezoelectric element with a feedback mechanism inside and has the following basic principles: as shown in fig. 1, the external view of the piezoelectric element is an electrostatic capacitance type element in which a piezoelectric material is sandwiched between two electrodes. In fig. 1, 1 is a piezoelectric element; 2 is a parallel plane piezoelectric material; 3 is a silver coating coated on the surface of the piezoelectric material and is a positive electrode; 4 is a conductor adhered with piezoelectric material and is a negative electrode; 5 is a conductor wire of a positive electrode; and 6 is a conductor line of a negative electrode.

The piezoelectric element has a multiple-input multiple-output characteristic, and applications based on the multiple-input multiple-output characteristic include: FIG. 6 is a diagram of a frame line for voltage-to-displacement transition in a piezoelectric element; FIG. 7 is a block diagram of the force to voltage conversion in a piezoelectric element; FIG. 8 is a diagram of a frame line for voltage-to-displacement transition in a piezoelectric element; FIG. 9 is a block diagram of the force to voltage conversion in a piezoelectric element; fig. 6 to 9 are block diagrams showing physical quantity conversion forms of piezoelectric elements; wherein 11-1 represents a frame line diagram for converting from voltage to displacement; 11-2 shows a block diagram of the force to voltage transition.

For a piezoelectric element that functions in a piezoelectric element, a function of converting mechanical energy into electric energy, a function of converting electric energy into mechanical energy, and a function of electrical impedance are realized by a piezoelectric phenomenon, and a function of converting thermal energy into electric energy is realized by a pyroelectric effect. Where 11-1 represents the conversion characteristics from force to voltage and from temperature to voltage. 11-2 represents the conversion characteristics from voltage and temperature to displacement. In the absence of temperature change, the relationship of 11-1 to 11-2 is referred to as the reversibility of the piezoelectric element, but its only essence is that a feedback system exists in the piezoelectric element and the input and output of the feedback system are different.

The piezoelectric element is a negative feedback system that can achieve a force conversion from force to displacement, from displacement to charge, from charge to voltage or current, and from voltage to the opposite of the applied force. A physical quantity of any one of force, displacement, charge, voltage, current, or temperature may be input to the feedback system. Further, any physical quantity may be output. For example, if a voltage is used as an input and a displacement is used as an output, the conversion element is displaced from the voltage direction. When a voltage of a constant frequency is input, the vibration generator becomes a mechanical or acoustic vibration generator, and a buzzer for generating a sound of the frequency is generated by placing a vibrating electrode in a helmholtz resonator which resonates with the frequency. When the electrode surface is deformed by applying a force in the opposite direction and a deformation displacement change is input, a voltage is output. The principle is applied to vibration sensors and igniters. A current input/voltage output device of a piezoelectric element has a narrow-band impedance change with respect to frequency, and is widely used as a narrow-band bandpass filter. There are also an energy collector which is provided with a piezoelectric element on a floor or the like and which accumulates electric power generated by floor vibration to serve as a power source, and a sensor which is sandwiched under the legs of a bed to protect the piezoelectric element from damage and captures biological information of a person crossing the bed. The causal relationship between the forward direction from the force to the voltage and the reverse direction from the voltage to the force can be defined as the reversibility of the piezoelectric element, but the essence is that the input to the feedback system is the voltage and the output is the displacement; the input is taken as the force and the output as the difference in displacement.

The invention provides a piezoelectric element, which realizes application of a piezoelectric element with multiple-input and multiple-output characteristics in automobiles. Specifically, the present invention utilizes the characteristics of the piezoelectric element in its interior as shown in fig. 6 to 9 to convert the physical quantity and at the same time utilizes the characteristics of the cyclic feedback system to make the piezoelectric element alone or two piezoelectric elements into an integrated unit, which is effective as the following products: an audio speaker system such as an automobile, a vibration sensor for monitoring the unevenness of a running road surface to perform suspension control, measuring an impact at the time of collision of the automobile to determine the deployment of an airbag, and a sensor for sensing body vibration accompanying the theft of the automobile at the time of parking. In addition, a change in the temperature of the roof of the automobile is sensed to provide an on-off signal to the automatic air conditioner. Further comprising: a power source of a transmitter for wirelessly transmitting an impact signal by using power output from a piezoelectric element, and an automobile integrated electronic device used as a signal source, which are caused by vibration due to a large impact.

Accordingly, the present invention provides a piezoelectric element that can be a single device multi-function (actuator, sensor, power source) element, and an automotive integrated electronics device. An integrated electronic device for an automobile is a device for supplying electric power by using one or two integrated piezoelectric elements that can realize a speaker mounted on a vehicle such as an automobile; a sensor for sensing sound, road surface condition, collision, vibration generated during theft, and temperature change as a sensor; and applications in which the power saving wireless device is driven by power output from a vibration sensor generated when large vibration is applied.

Therefore, the present invention provides a piezoelectric element having a feedback loop performance and thus having a multiple-input multiple-output characteristic, specifically including:

Based on the multiple-input multiple-output characteristics of the piezoelectric element, the following automobile integrated electronic devices can be manufactured: multiple input-multiple output actuators, sensors, speakers, wireless transmitter power supplies, multivariable sensor systems, and integrated electronic systems that integrate speakers and multivariable sensor systems.

Wherein, the sensor includes: acoustic sensors, vibration sensors, and temperature change sensors.

The piezoelectric element functions as a speaker when a voltage is input, a deformation or a displacement is output, and the displacement is transmitted to an acoustic panel.

When a force of vibration or a displacement of vibration generated by applying the force is input to the piezoelectric element and a voltage is output, the piezoelectric element functions as a vibration sensor that converts vibration into a voltage.

When sound pressure is converted into force on the pressure receiving surface, the force is used as an input of the piezoelectric element, and the microphone functions.

The temperature sensor functions as a temperature change sensor if the temperature change is used as an input and the voltage is used as an output.

The following embodiments of the respective devices are described in detail:

example 1: loudspeaker

The speaker includes: apiezoelectric element 1, avibration plate 13, athin rod 12, a mass 1-1, and anaudio function portion 15; theaudio function part 15 comprises a sound source 15-1, an audio amplifier 15-2 and a step-up transformer 15-3;

a mass block 1-1 used for realizing the stability of thepiezoelectric element 1 is arranged at the periphery of a negative electrode plate of thepiezoelectric element 1; in order to efficiently apply the vibration generated by the piezoelectric element to the vibratingplate 13, thethin rod 12 is attached to the center portion of the piezoelectric element having the largest vibration amplitude, and the piezoelectric element and the vibratingplate 13 are connected and fixed to each other, so that the piezoelectric element does not move away from the vibratingplate 13 due to the vibration of the vibratingplate 13. Namely: one end of thethin rod 12 is connected to the central portion of thepiezoelectric element 1 where the vibration amplitude is maximum; the other end of thethin rod 12 is connected to the center of the vibratingplate 13;

the mass block 1-1 has the following functions: when the back surface of the piezoelectric element is not fixed, a mass is provided around the piezoelectric element so that the piezoelectric element itself becomes a fixed point.

In the case where the piezoelectric element is not in contact with other parts, the stationary point of the mass block 1-1 has an effect of suppressing the vibration of the piezoelectric element. In the case where the vibration surface of the piezoelectric element is not fixed, if the piezoelectric element is fixed to another member, it is not necessary to attach a mass for realizing the fixed point.

Thin rod 12: is a member for transmitting the vibration of the piezoelectric element to the vibration plate. The reason why the rod (stick) for transmitting the vibration of the piezoelectric element to the vibrating plate is made thin is that: the free vibration of the vibration plate is not suppressed. When the entire vibration surface of the piezoelectric element is brought into close contact with or bonded to the vibration plate, if the vibration mode of the piezoelectric element is not matched with the vibration mode of the vibration plate, the transmission of the vibration is hindered, that is, the mechanical impedance cannot be matched. When a voltage is applied by the thin rod, the vibration transmission is not hindered even if the vibration mode is different, and high mechanical impedance matching is always achieved.

Therefore, mechanical impedance matching based on thin rods (sticks): in order to match the vibration surface of the piezoelectric element with the mechanical impedance, acoustic vibration is transmitted from a point of an antinode of the vibration surface of the piezoelectric element to the vibration surface via the thin rod.

The sound source 15-1 is connected to thepiezoelectric element 1 after passing through the audio amplifier 15-2 and the booster transformer 15-3 in sequence;

the working process is as follows:

the sound source 15-1 generates a sound signal in a voltage form, the audio amplifier 15-2 amplifies the sound signal in the voltage form, the sound signal is boosted by the booster transformer 15-3 to obtain a boosted sound signal in the voltage form, and the boosted sound signal is transmitted to thepiezoelectric element 1;

thepiezoelectric element 1 converts the boosted sound signal in the form of voltage into a corresponding vibration displacement signal, and transmits the vibration displacement signal to thevibration plate 13 through thethin rod 12, so that thevibration plate 13 vibrates, amplified sound is emitted, and a loudspeaker function is realized;

the audio amplifier 15-2 and thepiezoelectric element 1 realize impedance matching; the mechanical vibration of the maximum displacement vibration plane of thepiezoelectric element 1 and the mechanical vibration of thevibration plate 13 are mechanically impedance-matched, thereby efficiently converting the vibration of the sound source 15-1 into the vibration of thevibration plate 13.

In the present invention, the sound source 15-1 applies a voltage to an audio signal. The signal is voltage-amplified by the audio amplifier 15-2, and impedance matching is achieved by the step-up transformer 15-3. The amplifier in the transistor is a current amplifier, and the impedance of the amplifier is lower to 8 omega and 16 omega t. On the other hand, in the case where the capacitance of the piezoelectric element is, for example, 0.4 μ F, the impedance is 400 Ω even when the piezoelectric element is driven at 1kHz, and the impedance matching between the amplifier and the piezoelectric element of the load cannot be achieved in the transistor. Thus, the step-up transformer 15-3 selects a transformer in which the primary-side number of turns n1 is smaller than the secondary-side number of turns n2 and n1: n2 is, for example, about 1:10, and the internal resistance of the secondary-side transformer is about 400 Ω.

The invention therefore proposes in particular an electrical impedance matching based on the boosting of the voltage: matching the amplifier to the impedance of the piezoelectric element uses a power-saving boost acoustic transformer.

Example 2: vibration sensor

The vibration sensor includes: the device comprises apiezoelectric element 1, a signal amplifier 16-1, a vibration filter and a vibration sensing end;

the force of vibration sensed by the vibration sensing end or displacement of vibration generated by applying the vibration force is filtered by the vibration filter to form vibration waves of a first frequency band, and the vibration waves are amplified by the signal amplifier 16-1 and transmitted to thepiezoelectric element 1;

thepiezoelectric element 1 converts the sensed vibration wave into a voltage signal and outputs the voltage signal, thereby realizing the function of a vibration sensor for converting vibration into voltage;

example 3: acoustic sensor

The acoustic sensor includes: thepiezoelectric element 1, the signal amplifier 16-1, the audio filter and the sound sensing end; the sound sensing end senses sound pressure, the sound pressure is filtered by the audio filter, amplified by the signal amplifier 16-1 and transmitted to thepiezoelectric element 1;

the pressure-receiving surface of thepiezoelectric element 1 converts the sensed sound pressure into force, and the force is used as the input of thepiezoelectric element 1; thepiezoelectric element 1 converts force into a voltage signal and outputs the voltage signal, thereby realizing an acoustic function of converting sound vibration into voltage;

when the piezoelectric element alone is used as the sound generating apparatus, the conventional manner can only generate a buzzer-level sound by the piezoelectric element and the helmholtz resonator. In addition, the piezoelectric element is an electrostatic capacitance type driver and has extremely high input impedance. However, the electrodes of the piezoelectric element vibrate in a wide range of voltage bands, impedance matching between the acoustic amplifier and the piezoelectric element is appropriately obtained in the circuit, and impedance matching between mechanical vibration of the piezoelectric element and mechanical sound of the acoustic resonance mechanism is appropriately obtained, whereby electric musical vibration can be efficiently converted into acoustic vibration in a wide band.

Example 4: temperature sensor

The temperature sensor includes: the temperature sensor comprises apiezoelectric element 1, a signal amplifier 16-1, a temperature filter and a temperature sensing end; the temperature sensing end senses the temperature variation, the temperature variation is filtered by the temperature filter, amplified by the signal amplifier 16-1 and transmitted to thepiezoelectric element 1;

thepiezoelectric element 1 converts the temperature variation into a voltage signal and outputs the voltage signal, thereby realizing a temperature sensor function of converting the temperature variation into a voltage.

Example 5: wireless transmitter

The wireless transmitter power supply includes apiezoelectric element 1;

thepiezoelectric element 1 is installed inside an automobile; when a large collision occurs to the automobile, the vibration generated by the collision is used as the input of thepiezoelectric element 1, and thepiezoelectric element 1 converts the vibration generated by the collision into electric energy to be used as a power supply and a signal source of the wireless transmitter.

Example 6: multivariable sensor system

Multivariate sensor system:

multivariate sensor systems refer to: the functions of vibration sensing, sound sensing and temperature sensing are realized simultaneously by using frequency division and through one piezoelectric element;

specifically, the multivariable sensor system includes: the device comprises apiezoelectric element 1, a signal amplifier 16-1, a filter 16-2, a vibration sensing end, a sound sensing end and a temperature sensing end;

the filter 16-2 comprises an audio filtering unit, a vibration filtering unit and a temperature filtering unit;

the vibration sensing end is connected to the input end of the signal amplifier 16-1 through the vibration filtering unit; the sound sensing end is connected to the input end of the signal amplifier 16-1 through the audio filtering unit; the temperature sensing end is connected to the input end of the signal amplifier 16-1 through the temperature filtering unit; the output terminal of the signal amplifier 16-1 is connected to thepiezoelectric element 1;

the working principle is as follows:

the sound, vibration and temperature change frequency bands are different, and the audio filtering unit filters the sensed audio signal to the 1 st frequency band; the vibration filtering unit filters the sensed vibration signal to a2 nd frequency band; the temperature filtering unit filters the sensed temperature change signal to a 3 rd frequency band; the 1 st frequency band, the 2 nd frequency band and the 3 rd frequency band are different from each other, so that the signals are amplified by the signal amplifier 16-1 and then act on thepiezoelectric element 1; thepiezoelectric element 1 converts the sensed signal frequency band into a corresponding output.

For example, in the multivariable sensor system of the present invention, the impedance of the piezoelectric element is 400 Ω when driven at 1kHz in this example, 8k Ω or more when used as a vibration sensor at 50Hz or less, and 5Hz or less and 80k Ω or more when used as a temperature change sensor, and thus the multivariable sensor system becomes a high input impedance sensor. Thus, the input impedance of the signal amplifier 16-1 must be sufficiently large compared to these impedances. The voltage amplified by the signal amplifier 16-1 having such a high input impedance simultaneously functions as an acoustic sensor (microphone), a vibration sensor, and a temperature change sensor. The reason why the functions can be simultaneously performed is that the sound, vibration, and temperature change frequency bands are different and can be separated by a filter.

Specifically, in the filter 16-2, the audio filtering unit is in a frequency band from 100Hz to 10 kHz. The original audio frequency band is 20Hz to 20kHz, but vibrations other than sounds are sensed even when the entire band is covered with a microphone in an automobile, and therefore, 100Hz to 10kHz are used to exclude these sounds. The speech in this band is used as an input element for the human-machine interface between the car and the driver. In addition, the sensor is used for sensing abnormal sounds generated during the driving of the automobile and inputting sound for diagnosis.

In the filter 16-2, the vibration filter unit is, for example, a frequency band from 5Hz to 50 Hz. The vibrations of the vehicle during driving are in this frequency band, and the vibrations during a collision are also in this frequency band. Therefore, the state of unevenness on the road surface can be estimated using the vibration and the vehicle speed when the vehicle is traveling. The signal can be used as a signal for traction control and active suspension control of the vehicle according to the state. In addition, when the automobile is stolen, vibration and sound are generated along with damage of the window and forced opening of the door. This can be sensed in a powerless state using the acoustic or vibration sensor function of the piezoelectric element. Thereby realizing the following applications: when the signal is sensed, the power of the alarm device is turned on by the signal and then switched to a speaker function to sound an alarm.

In the filter 16-2, the temperature filter unit is, for example, a frequency band from 0.1Hz to 5 Hz. The piezoelectric element is a capacitance-type element, and converts a change amount into a voltage, not an absolute value of a temperature, even if a voltage generated by a pyroelectric effect exists. Thus, the temperature sensor in the present invention is a temperature change sensing sensor. As shown in fig. 12, the piezoelectric element is provided in a space between the roof lining and the roof portion of the vehicle body and in a portion directly affected by a change in the outside air temperature. Therefore, the temperature change can be sensed with good sensitivity. The temperature change signal can be used as a control signal for an air conditioner of an automobile.

Example 7: integrated electronic system A1

Integrated electronic system integrating a loudspeaker and a multivariable sensor system:

integrated electronic system integrating a loudspeaker and a multivariable sensor system refers to: switching one piezoelectric element into a loudspeaker function and a multivariable sensor system function for use in a time division manner; namely: the multivariable sensor system and the loudspeaker share the same piezoelectric element.

The specific implementation mode comprises the following steps:

the piezoelectric sensor comprises apiezoelectric element 1, a loudspeaker module, a multivariable sensor system module and a selector switch; the change-over switch comprises a first change-over switch 14-1 and a second change-over switch 14-2 which are linked;

the speaker module includes: a vibratingplate 13, athin rod 12, a mass block 1-1, a sound source 15-1, an audio amplifier 15-2 and a booster transformer 15-3;

the multivariate sensor system module comprises: the device comprises a signal amplifier 16-1, a filter 16-2, a vibration sensing end, a sound sensing end and a temperature sensing end;

a mass block 1-1 used for realizing the stability of thepiezoelectric element 1 is arranged at the periphery of a negative electrode plate of thepiezoelectric element 1; one end of thethin rod 12 is connected to the central portion of thepiezoelectric element 1 where the vibration amplitude is maximum; the other end of thethin rod 12 is connected to the center of the vibratingplate 13;

thepiezoelectric element 1 passes through the second change-over switch 14-2 and then is sequentially connected with a booster transformer 15-3, an audio amplifier 15-2 and a sound source 15-1; the input end of the sound source 15-1 is provided with a first change-over switch 14-1; the first change-over switch 14-1 and the second change-over switch 14-2 are linked;

the filter 16-2 is connected to the second switch 14-2 through the signal amplifier 16-1.

Therefore, the first changeover switch 14-1 and the second changeover switch 14-2 are time-division changeover switches for use when the electronic device is used as a speaker and as a sensor. When the speaker is not used, the sensor always functions as a sensor. The reason why the sensor continues to function as a sensor at all times is: in the piezoelectric phenomenon and the pyroelectric effect, these phenomena occur even when power is not supplied to the piezoelectric element, and a voltage can be generated as an output of the piezoelectric element.

In the integrated electronic system a1 of the present example, one piezoelectric element is used by switching between the speaker function and the multivariable sensor system function, and therefore, the speaker function and the sensor function are performed by time division by the single piezoelectric element. This simplifies the wire harness and reduces the cost.

The embodiment has the following advantages:

(1) time-division utilization of the versatility of piezoelectric elements:

the present invention cannot use both speaker and sensor functions when only one piezoelectric element is used. However, when the speaker is not used, the piezoelectric element can be used in a frequency division manner to simultaneously function as a microphone, a vibration sensor, a sensor for sensing a temperature change of the roof of the automobile, and a power source. This makes it possible to simplify the use of a plurality of conventional sensors and the accompanying complicated sensor harness. Further, the weight and power of the acoustic device can be greatly reduced.

(2) The frequency division function utilizes:

in a method in which a piezoelectric element is used as a power source of a microphone, a vibration sensor, a temperature change sensing sensor, or a wireless transmitter that notifies a large impact at the same time in a period in which a speaker is not used, the frequency band in which the piezoelectric element senses sound is several hundred hertz or more, vibration from a road surface, vibration accompanying a collision or theft is 50Hz or less, and a temperature change is 5Hz or less, and these can be separated by a filter. The frequency separation can be performed using a filter and the function can be used at the same time.

Specifically, the method comprises the following steps: a filter for passing an audio frequency band (100Hz to 10kHz), a filter for passing an automobile vibration frequency band (5Hz to 50Hz), and a filter for passing a temperature change frequency band (0.1Hz to 5 Hz).

Example 8: integrated electronic system A2

An integrated electronic system integrating a speaker and a multivariate sensor system, comprising: a speaker unit and a multivariable sensor system unit;

the loudspeaker unit comprises a vibratingplate 13, athin rod 12, a first piezoelectric element, a mass block 1-1, a sound source 15-1, an audio amplifier 15-2 and a booster transformer 15-3;

the multivariable sensor system unit comprises: the wireless transmitter comprises a second piezoelectric element, a wireless transmitter power supply, a signal amplifier 16-1, a filter 16-2, a vibration sensing end, a sound sensing end and a temperature sensing end;

wherein: a mass block 1-1 used for realizing the stability of the first piezoelectric element is arranged at the periphery of a negative electrode plate of the first piezoelectric element; one end of thethin rod 12 is connected to the central portion of the first piezoelectric element where the vibration amplitude is maximum; the other end of thethin rod 12 is connected to the center of the first piezoelectric element; the first piezoelectric element is sequentially connected with a booster transformer 15-3, an audio amplifier 15-2 and a sound source 15-1;

the second piezoelectric element is connected to the filter 16-2 after passing through the signal amplifier 16-1; the power-taking position of the wireless transmitter power supply is the position from the second piezoelectric element to the cable of the signal amplifier 16-1;

the first piezoelectric element and the second piezoelectric element are integrally formed.

The piezoelectric element itself is inexpensive, and the cost is mainly wire harness installation. The embodiment of fig. 11 is a three-wire system in which two piezoelectric elements are integrated and a wire harness is also used as a ground wire, an audio power line, and a sensor signal line. With respect to the resulting cost, only one additional piezoelectric element and the wire harness are also provided as three electric wires, and the operation cost does not change, and therefore the influence on the overall cost is small. In addition, the following advantages are provided: by making the speaker and the sensor function independently, the sensor can always function even when the speaker is used, and a piezoelectric element most suitable for various applications can be selected.

This embodiment utilizes two piezoelectric elements, which are low cost and the elements themselves have no impact on cost. The two piezoelectric elements are integrated, and a three-wire cable including a ground wire, an audio terminal, and a sensor terminal is led out therefrom, whereby a harness for mounting can be simplified. The speaker function and the sensor function can be independently used in this manner, and a function requiring a sensor to be used all the time can be unconditionally realized. When the piezoelectric element is used exclusively for the sensor function, when a large impact is applied, electric power generated from the piezoelectric element becomes a power source and a signal source of the power-saving wireless device. Since the piezoelectric element operates without a power supply, it is possible to sense an impact without using a power source such as a battery, thereby realizing wireless communication.

Example 9: mounting position of automobile integrated electronic device

In both the embodiment of fig. 10 and the embodiment of fig. 11, the piezoelectric element is provided in a space between the roof head lining and the roof portion of the automobile body, as in the embodiment of fig. 12, that is: a piezoelectric element part of an automobile integrated electronic device is provided in a space part of a roof lining of an automobile. The car sun visor housing portion has a sufficiently large space in which the piezoelectric element or the two piezoelectric elements can be housed. By providing the piezoelectric element at this position, the following advantages can be obtained:

(1) the sound source is located in the vicinity of the ears, and vibrates a large area such as a headliner, so that even weak sound transmits sound to the ears with less attenuation, and the speaker can be driven with less driving power;

(2) the roof head lining has a high-pitched sound absorbing characteristic, and the piezoelectric element enhances the high-pitched sound absorbing characteristic to obtain a flat sound characteristic as a whole.

(3) The advantage of being a loudspeaker based on the position of the piezoelectric element: in the conventional automobile speaker, the sound generating surface is small and is provided at a position far from the ear, and it is difficult to hear the sound without playing a loud sound. The present invention provides a piezoelectric element in a headliner of an automobile, and uses the headliner as an acoustic vibrating plate, thereby playing sound near the ears, making even small ears sound large, and reducing acoustic attenuation due to distance by vibrating the large headliner. Thereby realizing a piezoelectric element of light weight and hearing sound with less electric power.

(4) The microphone has the advantages of being based on the arrangement position of the piezoelectric element: by disposing the piezoelectric element at the position of fig. 12, the piezoelectric element is placed in front of the driver, the influence of noise is less, and the sensitivity is high.

(5) The advantage of being a vibration sensor based on the position where the piezoelectric element is disposed: the roof head lining is at about 50Hz, and the vibration is captured without being attenuated. The vibration sensor is provided in the vicinity of the driver and captures the vibration in the vicinity most affecting the driver at the time of a collision of the vehicle, and the vibration of a frontal collision can be efficiently captured. In the case of large vibrations, the output power may become a power source and a signal source of the power-saving wireless transmitter.

Specifically, in the present invention, when the influence of the sound generated by the speaker is separated in the time division system, or when the vibration acceleration generated by the irregularities of the road surface is applied to the mass of the roof head lining to integrate the two piezoelectric elements, the force that vibrates is effectively transmitted to the piezoelectric elements via the thin rods (sticks). The high-frequency vibration absorbing function of the headliner itself is effectively utilized to sense low-frequency vibration generated by irregularities of the running surface. It is judged that the vibration acceleration for deploying the airbag is not a very large and continuous vibration but an acceleration on a large pulse generated in a short time. The force generated by the acceleration causes the piezoelectric element to generate a high voltage, which not only serves as a collision determination, but also generates electric power for wirelessly transmitting collision information. When the vehicle is notified of theft at the time of parking, no vibration is generated except for the influence of dynamic pressure of wind, ground vibration of a parking lot, and the like. These vibrations are different in frequency and change mode from those of a vehicle used as stolen. Thus, the stolen safety information of the automobile can be sensed.

(6) The advantage of being a temperature sensor based on the position where the piezoelectric element is arranged: by providing the piezoelectric element at the position of fig. 12, the wind generated when the automobile is running is received near the position of the piezoelectric element, and a temperature change with a short delay in temperature change due to the sound volume of the automobile body and a quick response can be sensed.

Specifically, the temperature change in the vehicle interior can be sensed with high sensitivity at the roof, which is exposed to the greatest amount of sunlight and radiates heat, with respect to the voltage change due to the polarization in the piezoelectric element, which is caused by the temperature change due to the pyroelectric effect of the piezoelectric element. The headliner also serves as a thermal insulator, and the space between the exterior roof of the vehicle and the headliner is most susceptible to changes in exterior temperature and can predict an increase in interior temperature. The information is used to generate a judgment signal of the indoor air conditioner.

It can be seen that the integrated electronic device for an automobile according to the present invention may be a single component implemented by a piezoelectric element, such as a vibration sensor, an acoustic sensor, a temperature sensor, a speaker, and a wireless transmitter power supply, or may be a multivariable sensor system implemented by a piezoelectric element, or may be an integrated electronic system implemented by a piezoelectric element that integrates a speaker and a multivariable sensor system. The integrated electronic system integrating the loudspeaker and the multivariable sensor system can be realized by adopting one piezoelectric element or two piezoelectric elements integrated together.

In summary, the present invention provides a piezoelectric element and an automotive integrated electronic device, which utilize the multi-input multi-output characteristic of the piezoelectric element to realize multi-functions and low cost, and the piezoelectric element and the automotive integrated electronic device include:

1) the piezoelectric element unit is used as an audio speaker by utilizing a function of converting electric energy into mechanical energy including sound;

2) the function of converting mechanical energy including sound into electric energy is utilized, and the output of a microphone, a vibration sensor, a temperature change sensor, or a piezoelectric element at the time of large vibration is used as a power source of a wireless transmitter.

3) In view of the feedback inherent to the piezoelectric element, an in-vehicle audio speaker system is constructed using one or two piezoelectric elements, and sound, vibration, temperature change sensor functions required for an automobile are simultaneously realized in a frequency division manner.

4) By providing the speaker and the sensor in the space portion of the roof lining of the automobile, a low-power and lightweight speaker system and a device for simultaneously measuring the physical quantity while using the output of one piezoelectric element in a frequency division manner are realized, whereby the number of components and the harness can be reduced, and further, the reliability and the cost can be improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements should also be considered within the scope of the present invention.

Claims

1. A piezoelectric element, characterized in that the piezoelectric element has feedback cycle performance so as to have multiple-input multiple-output characteristics, specifically comprising:

2. An automotive integrated electronics device based on the piezoelectric element of claim 1, comprising a multiple-input-multiple-output actuator, a sensor, a speaker, a wireless transmitter power supply, a multivariable sensor system, and an integrated electronics system integrating the speaker and multivariable sensor system.

3. The automotive integrated electronics of claim 2, wherein the speaker comprises: a piezoelectric element (1), a vibration plate (13), a thin rod (12), a mass block (1-1), and an audio function unit (15); the audio function part (15) comprises an audio source (15-1), an audio amplifier (15-2) and a step-up transformer (15-3);

the working process is as follows:

4. The automotive integrated electronics of claim 2, wherein the sensor comprises: vibration sensors, acoustic sensors, and temperature sensors;

5. The automotive integrated electronics unit according to claim 2, characterized in that the wireless transmitter power supply comprises a piezoelectric element (1);

6. The automotive integrated electronics of claim 2, wherein the multivariate sensor system is defined as: the functions of vibration sensing, sound sensing and temperature sensing are realized simultaneously by using frequency division and through one piezoelectric element;

the working principle is as follows:

7. The integrated automotive electronics unit of claim 2, wherein the integrated electronics system integrating the speaker and multivariable sensor system is: switching one piezoelectric element to a speaker function and a multivariable sensor system function in a time division manner; namely: the multivariable sensor system and the loudspeaker share the same piezoelectric element.

8. The automotive integrated electronics device of claim 2, wherein the integrated electronics system of the integrated speaker and multivariate sensor system comprises:

9. The automotive integrated electronics device of claim 2, wherein the integrated electronics system of the integrated speaker and multivariate sensor system comprises: a speaker unit and a multivariable sensor system unit;

10. The automotive integrated electronic device according to claim 2, characterized in that the piezoelectric element section of the automotive integrated electronic device is provided in a roof lining space section of an automobile.