Ultrasonic wave generator

Abstract

To provide a technique capable of efficiently driving multiple ultrasonic transducers with switchable ultrasonic focal positions according to the position of the focus.SOLUTION: An ultrasonic wave generator 1 includes multiple ultrasonic transducers 10, a focus switching unit, and a power adjustment unit. The focus switching unit includes a reference signal generator 30, a phase shifter 31, and a control unit 32. The power adjustment unit includes a reference voltage generator 40, multiple DC-DC converters 41, 42, and a switching unit 43. The focus switching unit switches the focal position of ultrasonic waves emitted from the ultrasonic transducers 10. The power adjustment unit adjusts the power supplied to each ultrasonic transducer 10 according to the focal position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an ultrasonic generator. [Background technology]

[0002] Patent Document 1 discloses an ultrasonic catheter. This ultrasonic catheter includes an ultrasonic vibration unit. The ultrasonic vibration unit includes a capacitive ultrasonic transducer array having a plurality of ultrasonic vibration elements. A control means for controlling the ultrasonic vibration unit includes a focus adjustment mechanism for adjusting the focal distance and depth of field of the ultrasonic waves emitted by the capacitive ultrasonic transducer array. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-090892 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, each ultrasonic transducer element has directionality. Therefore, if all ultrasonic transducer elements are driven with the same driving power regardless of the position of the focal point, there is a risk of inefficiency.

[0005] An object of the present disclosure is to provide a technology that can efficiently drive a plurality of ultrasonic transducers that can switch the position of the ultrasonic focal point in accordance with the position of the focal point. [Means for solving the problem]

[0006] The ultrasonic generator of the present disclosure comprises: A plurality of ultrasonic transducers; a focus switching unit that switches the focus positions of the ultrasonic waves emitted from the plurality of ultrasonic transducers; and a power adjusting unit that adjusts the power supplied to each of the ultrasonic transducers to a power that corresponds to the position of the focal point. [Effects of the Invention]

[0007] According to the present disclosure, a plurality of ultrasonic transducers capable of switching the position of the ultrasonic focal point can be driven efficiently in accordance with the position of the focal point. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating the configuration of an ultrasonic generator according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram illustrating the position of the focal point. [Figure 3] FIG. 3 is an explanatory diagram conceptually showing a power adjustment table corresponding to the focal point F1. [Figure 4] FIG. 4 is an explanatory diagram conceptually showing a power adjustment table corresponding to the focal point F2. [Figure 5] FIG. 5 is a graph showing the characteristics of the ultrasonic transducer. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] A plurality of ultrasonic transducers; a focus switching unit that switches the focus positions of the ultrasonic waves emitted from the plurality of ultrasonic transducers; an electric power adjusting unit that adjusts the electric power supplied to each of the ultrasonic transducers to an electric power according to the position of the focal point.

[0011] The ultrasonic generator described above can efficiently drive multiple ultrasonic transducers according to the position of the focal point by adjusting the power supplied to each ultrasonic transducer to the power according to the position of the focal point.

[0012] [2] The power adjustment unit adjusts the power supplied to each of the ultrasonic transducers to a power according to an inclination angle formed between the direction in which each of the ultrasonic transducers faces and the direction from the ultrasonic transducer to the focal point. The ultrasonic generator according to [1].

[0013] The ultrasonic generator can adjust the power supplied to each ultrasonic transducer to a value corresponding to the tilt angle.

[0014] [3] The power adjustment unit adjusts the power supplied to the ultrasonic transducer whose tilt angle exceeds a threshold to a first power, and adjusts the power supplied to the ultrasonic transducer whose tilt angle is equal to or smaller than the threshold to a second power greater than the first power. The ultrasonic generator according to [2].

[0015] The ultrasonic generator described above has a simple configuration in which it supplies more power to ultrasonic transducers with a relatively small tilt angle and less power to ultrasonic transducers with a relatively large tilt angle, thereby realizing a configuration in which multiple ultrasonic transducers can be efficiently driven according to the position of the focal point.

[0016] [4] The power adjusting unit adjusts the power supplied to each of the ultrasonic transducers to a power corresponding to the position of the focal point by adjusting the drive voltage applied to each of the ultrasonic transducers. The ultrasonic generator according to any one of [1] to [3].

[0017] The ultrasonic generator described above can adjust the power supplied to each ultrasonic transducer to a level that corresponds to the position of the focal point, by simply adjusting the drive voltage applied to each ultrasonic transducer.

[0018] [5] The power adjustment unit stores a power adjustment table indicating the correspondence between the position of the focal point and information for adjusting the power supplied to each of the ultrasonic transducers, and adjusts the power supplied to each of the ultrasonic transducers based on the position of the focal point switched by the focal point switching unit and information specified from the power adjustment table. An ultrasonic generator according to any one of [1] to [4].

[0019] The ultrasonic generator described above can simplify the configuration for efficiently driving a plurality of ultrasonic transducers in accordance with the position of the focal point by using the power adjustment table.

[0020] [Details of the embodiments of the present disclosure] The ultrasonic generator of the present disclosure is used for, for example, distance measurement, obstacle detection, non-destructive testing, aerial haptics, parametric speakers, acoustic levitation, and the like.

[0021] First Embodiment The ultrasonic generator 1 shown in FIG. 1 includes a plurality of ultrasonic vibrators 10. The plurality of ultrasonic vibrators 10 constitute an ultrasonic transducer array 11. The ultrasonic transducer array 11 is planar. When a high-frequency voltage is applied, the ultrasonic vibrators 10 vibrate and generate ultrasonic waves. The ultrasonic vibrators 10 have directionality.

[0022] The ultrasonic generator 1 includes a drive circuit 20 and an output circuit 21. The drive circuit 20 generates and outputs a drive voltage to be applied to the ultrasonic transducer 10. The output circuit 21 adjusts the signal output from the drive circuit 20 to a drivable current and outputs it to the ultrasonic transducer 10. The drive circuit 20 and the output circuit 21 are provided individually corresponding to each ultrasonic transducer 10.

[0023] The ultrasonic generator 1 includes a reference signal generator 30, a phase shifter 31, and a control unit 32. The reference signal generator 30, the phase shifter 31, and the control unit 32 correspond to an example of a focus switching unit.

[0024] The reference signal generator 30 generates, for example, a square wave or a sine wave of a predetermined frequency. A phase shifter 31 is provided for each drive circuit 20. Each phase shifter 31 shifts the phase of the square wave or sine wave input from the reference signal generator 30 based on phase information input from the control unit 32, and outputs the shifted wave to the corresponding drive circuit 20.

[0025] The control unit 32 is configured by, for example, an MCU (Micro Controller Unit) or an FPGA (Field Programmable Gate Array).

[0026] The control unit 32 adjusts the phase shift information input to each phase shifter 31, thereby adjusting the phase of the driving voltage applied to each ultrasonic transducer 10 and switching the position of the focus of the ultrasonic waves emitted from the multiple ultrasonic transducers 10.

[0027] For example, when a user performs a focus switching operation, the control unit 32 switches the focus to a position corresponding to the result of the focus switching operation. The focus position is the position where the sound pressure is greatest. The focus position is identified as the position where the sound pressure is greatest when a sound pressure distribution map is created, for example.

[0028] The control unit 32 stores in advance, for example, a phase-shift table indicating the correspondence between the focal position and the phase shift amount of each ultrasonic transducer 10. The control unit 32 specifies the phase shift amount of each ultrasonic transducer 10 based on the focal position corresponding to the result of the focus switching operation and the phase-shift table. The control unit 32 then inputs phase shift information indicating the specified phase shift amount to the phase shifter 31 corresponding to each ultrasonic transducer 10. Each phase shifter 31 shifts the phase of the square wave or sine wave input from the reference signal generator 30 so that the phase shift amount corresponds to the phase shift amount indicated by the input phase shift information. This adjusts the phase of the drive voltage generated by each drive circuit 20, and switches the focal position of the ultrasound waves emitted from the multiple ultrasonic transducers 10.

[0029] The ultrasonic generator 1 includes a reference voltage generator 40, a plurality of DC-DC converters 41 and 42, and a switching unit 43. The reference voltage generator 40, the plurality of DC-DC converters 41 and 42, the switching unit 43, and the control unit 32 correspond to an example of a power adjustment unit.

[0030] The reference voltage generator 40 generates a reference voltage. The DC-DC converters 41 and 42 are controlled by the control unit 32 and increase or decrease the reference voltage generated by the reference voltage generator 40 to generate a desired voltage. The multiple DC-DC converters 41 and 42 generate different voltages. In this embodiment, the DC-DC converter 41 generates a first voltage, and the DC-DC converter 42 generates a second voltage that is greater than the first voltage.

[0031] The switching unit 43 is provided for each drive circuit 20. The switching unit 43 is configured with, for example, a switch. The switching unit 43 switches the DC-DC converter connected to the drive circuit 20. Specifically, the switching unit 43 switches between a first state in which the drive circuit 20 is connected to the DC-DC converter 41 and a second state in which the drive circuit 20 is connected to the DC-DC converter 42. When the switching unit 43 is in the first state, a first voltage is input to the drive circuit 20. The drive circuit 20 to which the first voltage is input generates a first AC drive voltage using a signal input from the phase shifter 31. When the switching unit 43 is in the second state, a second voltage is input to the drive circuit 20. The drive circuit 20 to which the second voltage is input generates a second AC drive voltage using a signal input from the phase shifter 31. For example, when a voltage of 10 V is input, the drive circuit 20 generates a drive voltage of 10 Vpp (Voltage peak to peak).

[0032] The control unit 32 adjusts the voltage input to the drive circuit 20 by controlling the switching unit 43. The drive circuit 20 generates an AC drive voltage based on the voltage input to itself and the signal input from the phase shifter 31. The drive voltage signal generated by the drive circuit 20 is amplified by the output circuit 21 and applied to the ultrasonic transducer 10. In other words, the control unit 32 adjusts the voltage applied to the drive circuit 20, thereby adjusting the drive voltage applied to the ultrasonic transducer 10 and adjusting the power supplied to the ultrasonic transducer 10.

[0033] The control unit 32 adjusts the power supplied to each ultrasonic transducer 10 to power corresponding to the position of the focal point. The control unit 32 pre-stores a power adjustment table indicating the correspondence between, for example, the position of the focal point and information for adjusting the power supplied to each ultrasonic transducer 10. In this embodiment, the information for adjusting the power supplied to each ultrasonic transducer 10 is information indicating the voltage to be input to the drive circuit 20 corresponding to each ultrasonic transducer 10. The control unit 32 specifies the voltage to be input to the drive circuit 20 corresponding to each ultrasonic transducer 10 based on, for example, the position of the focal point corresponding to the result of the focus switching operation and the power adjustment table. The control unit 32 switches the state of the switching unit 43 so that the specified voltage is input to each drive circuit 20. As a result, the power supplied to each ultrasonic transducer 10 is adjusted to power corresponding to the position of the focal point.

[0034] The control unit 32 adjusts the power supplied to each ultrasonic transducer 10 to a power corresponding to the tilt angle formed between the direction in which each ultrasonic transducer 10 faces and the direction from the ultrasonic transducer 10 toward the focal point. The control unit 32 adjusts the drive voltage applied to each ultrasonic transducer 10 to a drive voltage corresponding to the tilt angle, thereby adjusting the power supplied to each ultrasonic transducer 10 to a power corresponding to the tilt angle.

[0035] The control unit 32 adjusts the power supplied to ultrasonic transducers 10 whose tilt angles exceed the threshold to a first power, and adjusts the power supplied to ultrasonic transducers 10 whose tilt angles are equal to or less than the threshold to a second power greater than the first power. Specifically, the control unit 32 adjusts the voltage input to the drive circuit 20 corresponding to the ultrasonic transducers 10 whose tilt angles exceed the threshold to a first voltage, thereby adjusting the power supplied to ultrasonic transducers 10 whose tilt angles exceed the threshold to the first power. The control unit 32 adjusts the voltage input to the drive circuit 20 corresponding to the ultrasonic transducers 10 whose tilt angles are equal to or less than the threshold to a second voltage, thereby adjusting the power supplied to ultrasonic transducers 10 whose tilt angles are equal to or less than the threshold to the second power.

[0036] For example, an example will be described in which the focal position is switched between focal points F1 and F2 as shown in FIG. 2. The ultrasonic transducers 10 are aligned in the X and Y directions. Thirteen ultrasonic transducers 10 are aligned in each of the X and Y directions. The ultrasonic transducers 10 are arranged facing the Z direction. The Y direction is perpendicular to the X direction. The Z direction is perpendicular to the X and Y directions. The ultrasonic transducers 10 are aligned at equal intervals. The ultrasonic transducers 10 are aligned at intervals of 0.01 m in the X and Y directions. The centers of the ultrasonic transducers 10 aligned in the X and Y directions are defined as the center of the ultrasonic transducer array 11. In this case, the coordinates of the focal point F1 shown in FIG. 2 are (X, Y, Z) = (0 m, 0 m, 0.1 m), and the coordinates of the focal point F2 shown in FIG. 2 are (X, Y, Z) = (-0.03 m, 0.02 m, 0.1 m).

[0037] Fig. 3 is an explanatory diagram conceptually showing a power adjustment table corresponding to the focal point F1 shown in Fig. 2. Fig. 4 is an explanatory diagram conceptually showing a power adjustment table corresponding to the focal point F2 shown in Fig. 2. Figs. 3 and 4 show the tilt angles of each of the ultrasonic transducers 10. For example, Fig. 3 shows that the tilt angle of ultrasonic transducer 10A is 0° and the tilt angle of ultrasonic transducer 10B is 40°.

[0038] 3, when the threshold value is 25°, the tilt angles of the ultrasonic transducers 10 outside the region surrounded by the frame FR1 exceed the threshold value, and the tilt angles of the ultrasonic transducers 10 inside the region surrounded by the frame FR1 are equal to or less than the threshold value. Therefore, when the focal position switches to the focal point F1, the control unit 32 adjusts the drive voltage applied to the ultrasonic transducers 10 outside the region surrounded by the frame FR1 to the first drive voltage, and adjusts the drive voltage applied to the ultrasonic transducers 10 inside the region surrounded by the frame FR1 to the second drive voltage.

[0039] 4, when the threshold value is 25°, the tilt angles of the ultrasonic transducers 10 outside the region surrounded by the frame FR2 exceed the threshold value, and the tilt angles of the ultrasonic transducers 10 inside the region surrounded by the frame FR2 are equal to or less than the threshold value. Therefore, when the focal position switches to the focal point F2, the control unit 32 adjusts the drive voltage applied to the ultrasonic transducers 10 outside the region surrounded by the frame FR2 to the first drive voltage, and adjusts the drive voltage applied to the ultrasonic transducers 10 inside the region surrounded by the frame FR2 to the second drive voltage.

[0040] The applicant conducted an experiment under the following conditions. The ultrasonic transducer 10 has the characteristics shown in FIG. 5. FIG. 5 shows the relationship between sound pressure and applied voltage when the beam angle is 0°, 25°, and 30°. When the focal position is at focus F1, the first drive voltage is adjusted to 15 Vpp and the second drive voltage is adjusted to 30 Vpp. As a result, the sound pressure at focus F1 was increased by 0.5 dB and the current consumption was reduced by 11% compared to when 24 Vpp was applied to all ultrasonic transducers 10. Furthermore, when the focal position is at focus F2, the first drive voltage is adjusted to 15 Vpp and the second drive voltage is adjusted to 30 Vpp. As a result, the sound pressure at focus F1 was increased by 0.5 dB and the current consumption was reduced by 13% compared to when 24 Vpp was applied to all ultrasonic transducers 10.

[0041] As described above, the ultrasonic generator 1 can efficiently drive multiple ultrasonic transducers 10 according to the position of the focal point by adjusting the power supplied to each ultrasonic transducer 10 to the power according to the position of the focal point.

[0042] The ultrasonic generator 1 can adjust the power supplied to each ultrasonic transducer 10 to a level that corresponds to the tilt angle. The ultrasonic generator 1 can realize a configuration that efficiently drives multiple ultrasonic transducers 10 according to the focal position with a simple configuration that increases the power supplied to ultrasonic transducers 10 with a relatively small tilt angle and decreases the power supplied to ultrasonic transducers 10 with a relatively large tilt angle.

[0043] The ultrasonic generator 1 can adjust the power supplied to each ultrasonic transducer 10 to a power according to the position of the focal point by a simple configuration of adjusting the drive voltage applied to each ultrasonic transducer 10.

[0044] By using the power adjustment table, the ultrasonic generator 1 can simplify the configuration for efficiently driving the multiple ultrasonic transducers 10 in accordance with the focal position.

[0045] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. Furthermore, the various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any manner as long as they are not contradictory.

[0046] The orientation of some or all of the ultrasonic transducers may be inclined with respect to the Z direction.

[0047] The ultrasonic transducer array formed by a plurality of ultrasonic vibrations does not have to be flat. For example, the ultrasonic transducer array may be curved or may have a three-dimensional shape such as a sphere.

[0048] In the first embodiment, the focus switching unit switches the focus position by adjusting the phase of the drive voltage, but the present invention is not limited to this configuration. For example, the focus switching unit may switch the focus position by adjusting the frequency of the drive voltage.

[0049] In the first embodiment, the supply power is adjusted in two stages, but the supply power may be adjusted in three or more stages.

[0050] In the first embodiment, the control unit is configured to identify the phase shift amount of each ultrasonic transducer based on a phase shift table. However, the control unit may identify the phase shift amount of each ultrasonic transducer using another method. For example, the control unit may store position information of each ultrasonic transducer and calculate the phase shift amount of each ultrasonic transducer based on the position information so that the focal point is at a desired position, thereby identifying the phase shift amount of each ultrasonic transducer. Furthermore, in a configuration in which the orientations of all ultrasonic transducers are not the same, the control unit may identify the phase shift amount of each ultrasonic transducer by pre-storing the position information and orientation of each ultrasonic transducer and calculating the phase shift amount of each ultrasonic transducer based on the position information and orientation so that the focal point is at a desired position. This configuration makes it easy to accommodate a configuration in which the focal point is continuously changed like drawing a line.

[0051] In the first embodiment, the control unit is configured to determine the voltage to be input to the drive circuit corresponding to each ultrasonic transducer based on the power adjustment table. However, the control unit may determine the voltage to be input to the drive circuit corresponding to each ultrasonic transducer using a different method. For example, the control unit may store position information for each ultrasonic transducer, calculate the tilt angle of each ultrasonic transducer based on the position information and the focal position, and determine the voltage to be input to the drive circuit corresponding to each ultrasonic transducer based on the tilt angle. Furthermore, in a configuration in which the orientations of all ultrasonic transducers are not the same, the control unit may store the position information and orientation of each ultrasonic transducer in advance, calculate the tilt angle of each ultrasonic transducer based on the position information, orientation, and focal position, and determine the voltage to be input to the drive circuit corresponding to each ultrasonic transducer based on the tilt angle. This configuration makes it easy to handle a configuration in which the focal point changes continuously like drawing a line.

[0052] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0053] 1. Ultrasonic generator 10...Ultrasonic vibrator 10A...Ultrasonic vibrator 10B...Ultrasonic vibrator 11...Ultrasonic transducer array 20...Drive circuit 21...Output circuit 30...Reference signal generator (focus switching unit) 31...Phase shifter (focus switching section) 32...Control unit (focus switching unit, power adjustment unit) 40...Reference voltage generator (power adjustment section) 41...DC-DC converter (power adjustment section) 42...DC-DC converter (power adjustment section) 43...Switching unit (power adjustment unit) F1…Focus F2…Focus FR1...frame FR2...frame

Claims

1. A plurality of ultrasonic transducers; a focus switching unit that switches the focus positions of the ultrasonic waves emitted from the plurality of ultrasonic transducers; an electric power adjusting unit that adjusts the electric power supplied to each of the ultrasonic transducers to an electric power according to the position of the focal point.

2. The power adjustment unit adjusts the power supplied to each of the ultrasonic transducers to a power according to an inclination angle formed between a direction in which each of the ultrasonic transducers faces and a direction from the ultrasonic transducer toward the focal point. The ultrasonic generator according to claim 1 .

3. The power adjustment unit adjusts the power supplied to the ultrasonic transducer whose tilt angle exceeds a threshold to a first power, and adjusts the power supplied to the ultrasonic transducer whose tilt angle is equal to or smaller than the threshold to a second power greater than the first power. The ultrasonic generator according to claim 2 .

4. The power adjusting unit adjusts the power supplied to each of the ultrasonic transducers to a power corresponding to the position of the focal point by adjusting the drive voltage applied to each of the ultrasonic transducers. The ultrasonic generator according to any one of claims 1 to 3.

5. The power adjustment unit stores a power adjustment table indicating the correspondence between the position of the focal point and information for adjusting the power supplied to each of the ultrasonic transducers, and adjusts the power supplied to each of the ultrasonic transducers based on the position of the focal point switched by the focal point switching unit and information specified from the power adjustment table. The ultrasonic generator according to any one of claims 1 to 3.

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