CN115729384A - Three-dimensional pen type interaction system and method based on piezoelectric micro-mechanical ultrasonic transducer - Google Patents

Abstract

The invention provides a three-dimensional pen type interaction system and a three-dimensional pen type interaction method based on a piezoelectric micro-mechanical ultrasonic transducer, wherein the three-dimensional pen type interaction system comprises an ultrasonic pen, a receiving module and intelligent terminal equipment, a pressure sensor, an ultrasonic pen PMUT and an ultrasonic pen controller are arranged in the ultrasonic pen, and a receiving module controller and a plane receiving PMUT structure are arranged in the receiving module, so that the advantages of small size, low power consumption, low price, excellent performance and convenience in integration of the PMUT are utilized and combined with pen type human-computer interaction, the equipment size can be greatly reduced, the equipment price is reduced, and the equipment performance is improved.

Description

Three-dimensional pen type interaction system and method based on piezoelectric micro-mechanical ultrasonic transducer

Technical Field

The invention relates to the field of ultrasonic positioning, in particular to a three-dimensional pen type interaction system and a three-dimensional pen type interaction method based on a piezoelectric micro-mechanical ultrasonic transducer.

Background

With the development of information technology, the traditional man-machine interaction modes such as a keyboard and a mouse are difficult to meet the requirements of people on high-quality man-machine interaction. Pen-based interaction is an important way of human-computer interaction, and provides people with the greatest habituation through a paper-pen Metaphor (Metaphor) similar to the traditional one. Meanwhile, the pen-type man-machine interaction avoids the requirements on a keyboard and a mouse, and meets the requirements of miniaturization and portability of the existing intelligent terminal equipment. The most critical technology in pen type human-computer interaction is pen positioning, and the space positioning technology currently used in pen type human-computer interaction mainly comprises a laser positioning technology, an infrared optical positioning technology, a visible light positioning technology, computer vision, inertial sensor positioning and an ultrasonic positioning technology. In the positioning technology, the ultrasonic waves are not sensitive to color and light intensity; the ultrasonic wave has low sensitivity to light and electromagnetic field, and can be used in dark, dust or smoke, strong electromagnetic interference and other environments; the sensor structure formed by the ultrasonic transducer is simple to realize, low in manufacturing cost, simple and reliable in signal analysis and processing, and convenient to realize portability, integration and real-time control. Therefore, the ultrasonic positioning technology is widely developed in human-computer interaction.

The existing ultrasonic pen type human-computer interaction technology is mostly prepared based on the traditional piezoelectric ultrasonic transducer, wherein the principle of the piezoelectric transducer mainly utilizes the thickness vibration mode of piezoelectric ceramics to generate ultrasonic waves, because the resonant frequency of the thickness mode is only related to the thickness of the transducer, the ultrasonic transducers with different resonant frequencies are difficult to manufacture on the same plane, and when the ultrasonic transducer is applied to high frequency, the thickness needs to be controlled at submicron-level precision, and the processing difficulty is higher.

Therefore, it is necessary to provide a three-dimensional pen-type interactive system and method based on piezoelectric micro-mechanical ultrasonic transducer.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention provides a three-dimensional pen-type interactive system and method based on piezoelectric micromachined ultrasonic transducer, which is used to solve the problems of application and preparation of ultrasonic pen-type human-computer interaction in the prior art.

To achieve the above objects and other related objects, the present invention provides a piezoelectric micromachined ultrasonic transducer-based three-dimensional pen-type interaction system, comprising:

the ultrasonic pen comprises a pressure sensor, an ultrasonic pen PMUT and an ultrasonic pen controller, wherein the pressure sensor converts a received pressure signal into an electric signal and transmits the electric signal to the ultrasonic pen controller, and the ultrasonic pen controller starts the ultrasonic pen PMUT and sends an ultrasonic signal through the ultrasonic pen PMUT;

the receiving module comprises a receiving module controller and a planar receiving PMUT structure, the planar receiving PMUT structure comprises N (N is more than or equal to 3 non-collinear receiving PMUTs), the ultrasonic pen sends a synchronous signal to the receiving module, the planar receiving PMUT structure receives the ultrasonic signal and converts the ultrasonic signal into an electric signal to be transmitted to the receiving module controller, and the electric signal is analyzed by the receiving module controller to obtain the spatial position information of the ultrasonic pen;

and the intelligent terminal equipment receives the spatial position information of the ultrasonic pen to complete interaction.

Optionally, the ultrasonic pen and the receiving module operate in a wired mode or a wireless mode to transmit the synchronization signal.

Optionally, when the ultrasound pen and the receiving module operate in a wireless mode, the ultrasound pen further includes a first infrared sensor or a first radio frequency sensor electrically connected to the ultrasound pen controller, and the corresponding receiving module further includes a second infrared sensor or a second radio frequency sensor electrically connected to the receiving module controller.

Optionally, the ultrasonic pen comprises 1-3 pressure sensors.

Optionally, the PMUT in the pen interactive system is a PMUT array composed of PMUT array elements; the piezoelectric layer of the PMUT array element comprises one or a combination of an AlN piezoelectric layer, a ZnO piezoelectric layer, a PZT piezoelectric layer and a piezoceramic layer.

Optionally, the smart terminal device includes one or a combination of a PC, a smart phone, and a tablet computer; the receiving module and the intelligent terminal device work in a wired mode or a wireless mode.

Optionally, the pen interaction system further comprises a backplane.

Optionally, N of the receiving PMUTs in the planar receiving PMUT structure form a rectangular coordinate system.

The invention also provides an interaction method of the three-dimensional pen type interaction system based on the piezoelectric micro-mechanical ultrasonic transducer, which comprises the following steps:

the ultrasonic pen is awakened through the pressure sensor, and the pressure sensor converts a received pressure signal into an electric signal and transmits the electric signal to the ultrasonic pen controller;

the ultrasonic pen sends a synchronous signal to the receiving module, and simultaneously sends an ultrasonic signal through the ultrasonic pen PMUT;

after the receiving module receives the synchronous signal sent by the ultrasonic pen, the planar receiving PMUT structure receives the ultrasonic signal, converts the ultrasonic signal into an electric signal and transmits the electric signal to the receiving module controller, and the electric signal is analyzed by the receiving module controller to obtain the spatial position information of the ultrasonic pen;

and the receiving module sends the spatial position information of the ultrasonic pen to the intelligent terminal equipment to complete interaction.

Optionally, the obtaining the spatial position information of the ultrasonic pen includes the following steps:

selecting 3 non-collinear receiving PMUTs to form the planar receiving PMUT structure, establishing a coordinate system, acquiring coordinates of a first receiving PMUT, a second receiving PMUT and a third receiving PMUT, and setting the coordinates of the ultrasonic pen PMUT to (x, y, z);

acquiring the time t of the ultrasonic signal transmitted by the ultrasonic pen to reach the first receiving PMUT, the second receiving PMUT and the third receiving PMUT by taking the synchronous signal transmitted by the ultrasonic pen as a reference _m The amount of coordinate change of the ultrasonic signal to the first, second and third receive PMUTs is (Δ x) _m ，Δy _m ，Δz _m ) Setting the propagation velocity of the ultrasonic wave as c, according to the equation:

Δx _m ² +Δy _m ² +ΔZ _m ² ＝(ct _m ) ²

and solving an equation to obtain the spatial position information of the coordinates (x, y, z) of the ultrasonic pen PMUT.

As described above, the three-dimensional pen type interactive system and method based on the piezoelectric micromachined ultrasonic transducer of the present invention includes an ultrasonic pen, a receiving module, and an intelligent terminal device, where the pressure sensor, the ultrasonic pen PMUT, and the ultrasonic pen controller are disposed in the ultrasonic pen, and the receiving module is disposed with a receiving module controller and a planar receiving PMUT structure, so that the pressure sensor can convert a received pressure signal into an electrical signal and transmit the electrical signal to the ultrasonic pen controller, the ultrasonic pen controller starts the ultrasonic pen PMUT and transmits an ultrasonic signal through the ultrasonic pen PMUT, the ultrasonic pen sends a synchronization signal to the receiving module, the planar receiving PMUT structure in the receiving module receives the ultrasonic signal and converts the signal into an electrical signal to transmit to the receiving module controller, the receiving module controller analyzes the signal to obtain spatial position information of the ultrasonic pen, and the intelligent terminal device receives the spatial position information of the ultrasonic pen to complete interaction. The invention utilizes the advantages of small size, low power consumption, low price, excellent performance and convenient integration of the PMUT to combine with pen-type man-machine interaction, thereby greatly reducing the size and the price of equipment and simultaneously improving the performance of the equipment.

Drawings

Fig. 1 shows a schematic structural diagram of a three-dimensional pen-based interactive system based on piezoelectric micromachined ultrasonic transducers in an embodiment.

Fig. 2 shows a schematic structural diagram of an ultrasonic pen based on a piezoelectric micromachined ultrasonic transducer in an embodiment.

Fig. 3 shows a schematic structural diagram of a receiving module based on a piezoelectric micromachined ultrasonic transducer in an embodiment.

Fig. 4 is a schematic structural diagram of a PMUT array in an embodiment.

Fig. 5 is a schematic cross-sectional view of a PMUT array element in an embodiment.

Fig. 6 shows a block diagram of a three-dimensional pen-based interactive system based on piezoelectric micromachined ultrasonic transducers in an embodiment.

Fig. 7 shows a flow chart of an interaction method of the three-dimensional pen-type interaction system based on the piezoelectric micro-mechanical ultrasonic transducer in the embodiment.

Description of the element reference numerals

100. Base plate

200. Ultrasonic pen

201. Pen body

202. Infrared/radio frequency sensor

203. Ultrasonic pen PMUT

204. Pressure sensor

300. Receiving module

301. Receiving module body

302. First receiving PMUT

303. Second receiving PMUT

304. Third receive PMUT

305. Receiving infrared/radio frequency sensor

306. Fourth receive PMUT

307. Fifth receive PMUT

308. Sixth receiving PMUT

400. Intelligent terminal equipment

500 PMUT array

510 PMUT array element

501 Si substrate

502. Hollow cavity

503 Si structure layer

504. Bottom electrode

505. Piezoelectric layer

506. Top electrode

507 SiO ₂ Insulating layer

508. A first aluminum electrode

509. Second aluminum electrode

Detailed Description

At present, a Micro-Mechanical Ultrasonic Transducer (Micro-machined Ultrasonic Transducer, abbreviated as MUT) manufactured based on a Micro-Electro-Mechanical System (Micro-electromechanical System, abbreviated as MEMS) works in a bending mode, has a vibrating membrane with low rigidity, and has a resonant frequency controlled by an in-plane dimension, which has a low requirement on processing precision. With the gradual maturity of the MEMS ultrasonic transducer technology, the micromechanical ultrasonic transducer will gradually replace the traditional bulk piezoelectric transducer due to its advantages of high performance, low cost and easy mass production.

Micromachined ultrasonic transducers are mainly classified into two types: capacitive Micromachined Ultrasonic Transducers (CMUT) and Piezoelectric Micromachined Ultrasonic Transducers (PMUT). The CMUT utilizes a capacitor formed between an upper polar plate and a lower polar plate, a vibrating membrane is bent downwards through direct current bias voltage between metal electrodes, and then the membrane is driven to vibrate up and down through applying alternating current voltage with certain frequency, so that a medium is pushed to radiate ultrasonic waves. On the contrary, the vibration film keeps static bending balance under the action of the direct current bias voltage, and when the film is pushed to vibrate by ultrasonic waves, the change of the electrode spacing causes the change of the capacitance value, so that an electric signal related to the sound waves is generated. According to the operating principle of CMUT, it requires several hundreds volts of bias voltage and sub-micron interpolar gap in order to maintain high output pressure and sensitivity. The small gap results in a complicated manufacturing process and adhesion problems between the plates; a bias voltage of several hundred volts further increases the complexity of the system and also presents a safety hazard. The PMUT can realize mutual conversion of electric energy and acoustic energy based on the piezoelectric effect/inverse piezoelectric effect of the piezoelectric film, and compared with the CMUT, the PMUT has a simple structure, is easy to manufacture, and does not need a bias voltage of hundreds of volts, thereby being convenient to apply in the field of intelligent terminals.

The embodiment applies the PMUT to a three-dimensional pen type interactive system, and combines the advantages of small size, low power consumption, low price, excellent performance and convenient integration of the PMUT with pen type human-computer interaction, thereby greatly reducing the size of equipment, reducing the price of the equipment and simultaneously improving the performance of the equipment.

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Further, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between 8230 \ 8230;" between "means both end points are included.

In the context of this application, a structure described as having a first feature "on" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in the present embodiment are only for schematically illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

As shown in fig. 1, the present embodiment provides a three-dimensional pen-type interactive system based on a piezoelectric micromachined ultrasonic transducer, the pen-type interactive system comprising: the system comprises a bottom plate 100, an ultrasonic pen 200, a receiving module 300 and an intelligent terminal device 400.

Wherein the ultrasonic pen 200 and the receiving module 300 are both based on a Piezoelectric Micromachined Ultrasonic Transducer (PMUT) design. The base plate 100 is used to provide a writing surface so that the three-dimensional pen interaction system may not have this feature if the writing surface is flat. The ultrasonic pen 200 is used for transmitting and reflecting the spatial position information of the ultrasonic pen 200 at present; the receiving module 300 is configured to receive the ultrasonic signal transmitted by the ultrasonic pen 200, analyze the current spatial position information of the ultrasonic pen 200, and send the analyzed spatial position information to the intelligent terminal device 400 to complete interaction.

Specifically, as shown in fig. 2, in the present embodiment, the ultrasonic pen 200 includes a pen body 201, an infrared/radio frequency sensor 202, an ultrasonic pen PMUT203, and a pressure sensor 204. Further, as shown in fig. 6, the ultrasonic pen 200 further includes an ultrasonic pen controller for regulating and controlling the whole ultrasonic pen 200, and in order to facilitate the application of the ultrasonic pen 200, a power supply unit may be further disposed in the ultrasonic pen 200 to supply power to each sensor, but not limited thereto, for example, the ultrasonic pen 200 may also be powered in a wired mode.

In this embodiment, it is preferable that the ultrasonic pen 200 includes 2 pressure sensors 204, and the pressure sensors 204 are disposed on two sides of the pen body 201, so that pressure is applied to the ultrasonic pen 200 by holding it by hand, so that the pressure sensors 204 convert the received pressure signals into electrical signals, and transmit the electrical signals to the ultrasonic pen controller for waking up the ultrasonic pen 200, and then the ultrasonic pen controller activates the ultrasonic pen PMUT203 and sends ultrasonic signals through the ultrasonic pen PMUT203, but the number of the pressure sensors 204 is not limited thereto, and the number of the pressure sensors 204 may also be set to 1 or 3, and may be specifically set as needed, and is not limited herein.

Specifically, as shown in fig. 3, in the present embodiment, the receiving module 300 includes a receiving module body 301, a first receiving PMUT302, a second receiving PMUT303, a third receiving PMUT304, a receiving infrared/radio frequency sensor 305, a fourth receiving PMUT306, a fifth receiving PMUT307, and a sixth receiving PMUT308. The first receiving PMUT302, the second receiving PMUT303, the third receiving PMUT304, the fourth receiving PMUT306, the fifth receiving PMUT307 and the sixth receiving PMUT308 form a planar receiving PMUT structure, 6 receiving PMUTs in the planar receiving PMUT structure form a rectangular coordinate system, 3 receiving PMUTs are respectively arranged on an X axis and a Y axis which are perpendicular to each other, that is, a straight line where the first receiving PMUT302, the second receiving PMUT303 and the third receiving PMUT304 are located is taken as the Y axis, a straight line where the fourth receiving PMUT306, the fifth receiving PMUT307 and the sixth receiving PMUT308 are located is taken as the X axis, and an origin coordinate system is established by taking an intersection point of the straight lines where the X axis and the Y axis are located as an origin, but the number of the receiving PMUTs in the planar receiving PMUT structure is not limited thereto, and the planar receiving PMUT structure needs to include N or more than 3 non-collinear receiving PMUTs, such as N being 3, 4, 5, 6, 9 and the like. When 3 receiving PMUTs that are not collinear are arbitrarily selected in the receiving module 300, the position of the ultrasonic pen PMUT can be calculated. And when the number of the receiving PMUTs in the receiving module 300 is more than 3, the received data can be redundant, and the accuracy of positioning can be improved by using a redundant data processing algorithm. In addition, more than 3 receiving PMUTs may also ensure that the receiving module 300 may still operate normally when the receiving PMUTs fail, so as to ensure system stability.

Further, as shown in fig. 6, the receiving module 300 may further include an ultrasonic signal processing circuit, a receiving module controller, and a power supply unit. After the receiving infrared/radio frequency sensor 305 receives the synchronization signal sent by the ultrasonic pen 200, the planar receiving PMUT structure receives and processes the ultrasonic signal sent by the ultrasonic pen 200, converts the received ultrasonic signal into an electrical signal, transmits the electrical signal to the receiving module controller, performs analysis by the receiving module controller, obtains spatial position information of the ultrasonic pen 200, and sends the spatial position information to the intelligent terminal device 400.

As can be seen from fig. 2, fig. 3 and fig. 6, in this embodiment, it is preferable that the ultrasonic pen 200 and the receiving module 300 work in a wireless mode to transmit the synchronization signal, that is, the ultrasonic pen 200 is provided with an infrared/radio frequency sensor 202, and the corresponding receiving module 300 is provided with the receiving infrared/radio frequency sensor 305 corresponding to the infrared/radio frequency sensor 202, so that the ultrasonic pen 200 sends the synchronization signal to the receiving module 300 through the infrared/radio frequency sensor 202 and the receiving infrared/radio frequency sensor 305. The sensors used in the wireless transmission between the ultrasonic pen 200 and the receiving module 300 are not limited to infrared/radio frequency sensors, and the specific types can be selected according to the requirements.

In another embodiment, the ultrasonic pen 200 and the receiving module 300 can also operate in a wired mode, for example, the ultrasonic pen 200 can be directly connected to the receiving module 300, and the ultrasonic pen controller and the receiving module controller can directly implement the synchronization signal without providing the infrared/rf sensor 202 and the receiving infrared/rf sensor 305.

As an example, the PMUT in the ultrasonic pen 200 and the receiving module 300 is a PMUT array 500 composed of PMUT array elements 510.

Specifically, referring to fig. 4, the ultrasonic pen PMUT203, the first receiving PMUT302, the second receiving PMUT303, the third receiving PMUT304, the fourth receiving PMUT306, the fifth receiving PMUT307, and the sixth receiving PMUT308 related in this embodiment are PMUT arrays 500, that is, PMUT arrays 500 composed of a plurality of PMUT array elements 510, and the PMUT arrays 500 further include a plurality of top electrode pads and a plurality of bottom electrode pads. All PMUT array elements 510 in the PMUT array 500 shown in fig. 4 share a top electrode and a bottom electrode, and are respectively led out from a top electrode pad and a bottom electrode pad.

As shown in fig. 5, which is a cross-sectional structure diagram of the PMUT array element 510, the PMUT array element 510 in the PMUT array 500 is processed by MEMS technology and includes SiO from top to bottom ₂ An insulating layer 507, a top electrode 506, a piezoelectric layer 505, a bottom electrode 504, a Si structural layer 503, and a Si substrate 501. Wherein, the Si substrate 501 is etched with a cavity 502 to ensure the bending vibration of PMUT. The first aluminum electrode 508 and the second aluminum electrode 509 are used to lead out the bottom electrode 504 and the top electrode 506, respectively. When an alternating electric field is applied between the bottom electrode 504 and the top electrode 506, the PMUT array element 510 is driven by the transverse stress generated in the piezoelectric layer 505 to perform bending vibration, thereby generating ultrasonic waves. Wherein the number of PMUT array elements 510 of the PMUT array 500 is preferably greater than 2, and the PMUT array elements 510 may adopt the same structure or different structures. The piezoelectric layer 505 can be an AlN piezoelectric layer, a ZnO piezoelectric layer, a PZT piezoelectric layer, or a piezoceramic layer.

In this embodiment, it is preferable that all the PMUT array elements 510 of the PMUT array 500 have the same structure, and it is preferable that the piezoelectric layer 505 is an AlN piezoelectric layer, but the selection of the material, structure, and the like of the PMUT array 500 is not limited thereto.

As an example, the smart terminal device 400 may include one or a combination of a PC, a smartphone, and a tablet computer; the receiving module 300 and the intelligent terminal device 400 can operate in a wired mode or a wireless mode, and the type of the intelligent terminal device 400 and the communication mode with the receiving module 300 are not limited herein.

Referring to fig. 6 and 7, the embodiment further provides an interaction method of a three-dimensional pen-type interaction system based on a piezoelectric micromachined ultrasonic transducer, which includes the following steps:

the ultrasonic pen 200 is awakened through the pressure sensor 204, and the pressure sensor 204 converts the received pressure signal into an electric signal and transmits the electric signal to the ultrasonic pen controller;

the ultrasonic pen 200 sends a synchronization signal to the receiving module 300, and simultaneously sends an ultrasonic signal through the ultrasonic pen PMUT 203;

after the receiving module 300 receives the synchronization signal sent by the ultrasonic pen 200, the planar receiving PMUT structure receives the ultrasonic signal, converts the ultrasonic signal into an electrical signal and transmits the electrical signal to the receiving module controller, and the electrical signal is analyzed by the receiving module controller to obtain the spatial position information of the ultrasonic pen;

the receiving module 300 sends the spatial position information of the ultrasonic pen to the intelligent terminal device 400, and interaction is completed.

As an example, the obtaining of the spatial position information of the ultrasonic pen comprises the following steps:

selecting 3 non-collinear receiving PMUTs to form the planar receiving PMUT structure, establishing a coordinate system, acquiring coordinates of a first receiving PMUT, a second receiving PMUT and a third receiving PMUT, and setting the coordinates of the ultrasonic pen PMUT to (x, y, z);

acquiring the time t of the ultrasonic signal transmitted by the ultrasonic pen to reach the first receiving PMUT, the second receiving PMUT and the third receiving PMUT by taking the synchronous signal transmitted by the ultrasonic pen as a reference _m The amount of coordinate change of the ultrasonic signal to the first, second and third receive PMUTs is (Δ x) _m ，Δy _m ，Δz _m ) Setting the propagation speed of the ultrasonic wave as c, according to the equation:

Δx _m ² +Δy _m ² +ΔZ _m ² ＝(ct _m ) ²

and solving an equation to obtain the spatial position information of the ultrasonic pen PMUT with the coordinate of (x, y, z).

Specifically, in this embodiment, the straight lines of the first receiving PMUT302, the second receiving PMUT303 and the third receiving PMUT304 are connected to the fourth receiving PMUT306 and the fifth receiving PMUT306A coordinate system is established by taking the intersection point of straight lines where the receiving PMUT307 and the sixth receiving PMUT308 are located as an origin, the straight lines where the first receiving PMUT302, the second receiving PMUT303 and the third receiving PMUT304 are located are y-axes, the straight lines where the fourth receiving PMUT306, the fifth receiving PMUT307 and the sixth receiving PMUT308 are located are x-axes, and the straight line vertical to the xy plane is z-axis. Wherein the first receiving PMUT302, the second receiving PMUT303, and the fourth receiving PMUT306 are selected as the planar receiving PMUT structure, and the coordinates thereof are (0, y) _r1 ，0)，(0，y _r2 ，0)，(x _r4 ,0,0). The ultrasonic pen PMUT203 (x) on the ultrasonic pen 200 is based on the synchronization signal sent by the infrared/radio frequency sensor 202 ₁ ，y ₁ ，z ₁ ) The times of arrival of the transmitted ultrasonic waves at the first receiving PMUT302, the second receiving PMUT303 and the fourth receiving PMUT306 are t ₁ 、t ₂ 、t ₃ . Assuming that the propagation velocity of the ultrasonic wave is c, the following equation can be obtained:

x ₁ ² +(y ₁ -y _r1 ) ² +z ₁ ² ＝(ct ₁ ) ²

x ₁ ² +(y ₁ -y _r2 ) ² +z ₁ ² ＝(ct ₂ ) ²

(x ₁ -x _r4 ) ² +y ₁ ² +z ₁ ² ＝(ct ₃ ) ²

the position (x) of the ultrasonic pen PMUT203 can be obtained by solving the equation ₁ ，y ₁ ，z ₁ ). Similarly, any 3 other receiving PMUTs which are not on the same straight line are selected as the planar receiving PMUT structure, and the coordinates of the ultrasonic pen PMUT203, such as (x) respectively, can be obtained ₂ ，y ₂ ，z ₂ )、(x ₃ ，y ₃ ，z ₃ )、(x ₄ ，y ₄ ，z ₄ )、(x ₅ ，y ₅ ，z ₅ ) And the like. And the data are processed by a data redundancy algorithm, such as weighted average, kalman filtering and the like, so that more accurate coordinates of the ultrasonic pen PMUT203 can be obtained(x，y，z)。

In summary, the three-dimensional pen type interactive system and method based on the piezoelectric micromachined ultrasonic transducer of the present invention includes an ultrasonic pen, a receiving module and an intelligent terminal device, where the ultrasonic pen is provided with a pressure sensor, an ultrasonic pen PMUT and an ultrasonic pen controller, and the receiving module is provided with a receiving module controller and a planar receiving PMUT structure, so that the pressure sensor can convert a received pressure signal into an electrical signal and transmit the electrical signal to the ultrasonic pen controller, the ultrasonic pen controller starts the ultrasonic pen PMUT and transmits an ultrasonic signal through the ultrasonic pen PMUT, the ultrasonic pen sends a synchronization signal to the receiving module, the planar receiving PMUT structure in the receiving module receives the ultrasonic signal and converts the signal into an electrical signal to transmit the electrical signal to the receiving module controller, the receiving module controller analyzes the signal to obtain spatial position information of the ultrasonic pen, and the intelligent terminal device receives the spatial position information of the ultrasonic pen to complete interaction. The invention combines the advantages of small size, low power consumption, low price, excellent performance and convenient integration of the PMUT with pen-type human-computer interaction, thereby greatly reducing the size and the price of equipment and simultaneously improving the performance of the equipment.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Those skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims (10)

1. A piezoelectric micromachined ultrasonic transducer based three dimensional pen interaction system, comprising:

the ultrasonic pen comprises a pressure sensor, an ultrasonic pen PMUT and an ultrasonic pen controller, wherein the pressure sensor converts a received pressure signal into an electric signal and transmits the electric signal to the ultrasonic pen controller, and the ultrasonic pen controller starts the ultrasonic pen PMUT and sends an ultrasonic signal through the ultrasonic pen PMUT;

the receiving module comprises a receiving module controller and a planar receiving PMUT structure, the planar receiving PMUT structure comprises N more than or equal to 3 non-collinear receiving PMUTs, the ultrasonic pen sends a synchronous signal to the receiving module, the planar receiving PMUT structure receives the ultrasonic signal and converts the ultrasonic signal into an electric signal to be transmitted to the receiving module controller, and the spatial position information of the ultrasonic pen is acquired through analysis by the receiving module controller;

and the intelligent terminal equipment receives the spatial position information of the ultrasonic pen to complete interaction.

2. The pen interaction system according to claim 1, wherein: the ultrasonic pen and the receiving module work in a wired mode or a wireless mode to transmit the synchronous signal.

3. The pen interaction system according to claim 2, wherein: when the ultrasonic pen and the receiving module work in a wireless mode, the ultrasonic pen further comprises a first infrared sensor or a first radio frequency sensor which is electrically connected with the ultrasonic pen controller, and the corresponding receiving module further comprises a second infrared sensor or a second radio frequency sensor which is electrically connected with the receiving module controller.

4. The pen interaction system according to claim 1, wherein: the ultrasonic pen comprises 1-3 pressure sensors.

5. The pen interaction system according to claim 1, wherein: the PMUT in the pen type interactive system is a PMUT array formed by PMUT array elements; the piezoelectric layer of the PMUT array element comprises one or a combination of an AlN piezoelectric layer, a ZnO piezoelectric layer, a PZT piezoelectric layer and a piezoceramic layer.

6. The pen interaction system according to claim 1, wherein: the intelligent terminal equipment comprises one or a combination of a PC, a smart phone and a tablet computer; the receiving module and the intelligent terminal device work in a wired mode or a wireless mode.

7. The pen interaction system according to claim 1, wherein: the pen-based interactive system further comprises a backplane.

8. The pen interaction system according to claim 1, wherein: and N receiving PMUTs in the planar receiving PMUT structure form a rectangular coordinate system.

9. A method of interacting a three-dimensional pen-like interaction system based on piezoelectric micromachined ultrasonic transducers as claimed in any one of claims 1 to 8, comprising the steps of:

the ultrasonic pen is awakened through the pressure sensor, and the pressure sensor converts a received pressure signal into an electric signal and transmits the electric signal to the ultrasonic pen controller;

the ultrasonic pen sends a synchronous signal to the receiving module, and simultaneously sends an ultrasonic signal through the ultrasonic pen PMUT;

after the receiving module receives the synchronous signal sent by the ultrasonic pen, the planar receiving PMUT structure receives the ultrasonic signal, converts the ultrasonic signal into an electric signal and transmits the electric signal to the receiving module controller, and the electric signal is analyzed by the receiving module controller to obtain the spatial position information of the ultrasonic pen;

and the receiving module sends the spatial position information of the ultrasonic pen to the intelligent terminal equipment to complete interaction.

10. The pen interaction method according to claim 9, wherein: the method for acquiring the spatial position information of the ultrasonic pen comprises the following steps:

selecting 3 non-collinear receiving PMUTs to form the planar receiving PMUT structure, establishing a coordinate system, acquiring coordinates of a first receiving PMUT, a second receiving PMUT and a third receiving PMUT, and setting the coordinates of the ultrasonic pen PMUT to be (x, y, z);

acquiring the time t of the ultrasonic signal transmitted by the ultrasonic pen to reach the first receiving PMUT, the second receiving PMUT and the third receiving PMUT by taking the synchronous signal transmitted by the ultrasonic pen as a reference _m The amount of coordinate change of the ultrasonic signal to the first, second and third receive PMUTs is (Δ x) _m ，Δy _m ，Δz _m ) Setting the propagation speed of the ultrasonic wave as c, according to the equation:

Δx _m ² +Δy _m ² +ΔZ _m ² ＝(ct _m ) ²

and solving an equation to obtain the spatial position information of the coordinates (x, y, z) of the ultrasonic pen PMUT.

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