JP2013247982A - Processing apparatus, ultrasonic device, ultrasonic probe, and ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a processing apparatus with a simple configuration, capable of simultaneously emitting ultrasonic waves of a plurality of different frequencies; an ultrasonic device; an ultrasonic probe; and an ultrasonic diagnostic apparatus.SOLUTION: A processing apparatus 200 for an ultrasonic device 100 includes: a transmission unit 210 for outputting drive signals VDR1 to VDRn to the ultrasonic device 100; and a control unit 220 for controlling the transmission unit 210. The ultrasonic device 100 has first to n-th ultrasonic element groups UEG1 to UEGn having resonance characteristics of first to n-th (n is an integer ≥2). The transmission unit 210 outputs drive signals of a half-wave pulse as the drive signals VDR1 to VDRn to the first to n-th ultrasonic element groups UEG 1 to UEGn.

Description

  The present invention relates to a processing apparatus, an ultrasonic device, an ultrasonic probe, an ultrasonic diagnostic apparatus, and the like.

  As a device for irradiating ultrasonic waves toward an object and receiving reflected waves from interfaces with different acoustic impedances inside the object, for example, a diagnostic device for examining the inside of a human body or the flow velocity of blood in a blood vessel There are known diagnostic devices that detect the Doppler effect using the Doppler effect. In order to detect the blood flow rate with high accuracy, it is necessary to increase the number of samples used for Fourier analysis. For this purpose, there are methods such as increasing the sampling frequency or using ultrasonic waves having a plurality of different frequencies. For example, Patent Document 1 discloses a method of mixing ultrasonic elements having different frequencies. However, this method has problems such as a complicated transmission circuit configuration.

JP 2003-169800 A

  According to some aspects of the present invention, it is possible to provide a processing apparatus, an ultrasonic device, an ultrasonic probe, an ultrasonic diagnostic apparatus, and the like that can simultaneously emit a plurality of ultrasonic waves having different frequencies with a simple configuration.

  One aspect of the present invention is an ultrasonic device processing apparatus including a transmission unit that outputs a drive signal to the ultrasonic device, and a control unit that controls the transmission unit. , First ultrasonic element group to nth ultrasonic element group having resonance characteristics of a frequency from a first frequency to an nth (n is an integer of 2 or more), and the transmission unit includes the first ultrasonic element group To a processing apparatus that outputs a driving signal of a half-wave pulse as the driving signal for the ultrasonic element group to the n-th ultrasonic element group.

  According to one aspect of the present invention, an ultrasonic device having resonance characteristics of the first to nth frequencies is driven by a half-wave pulse of one frequency, so that ultrasonic waves of a plurality of different frequencies can be generated with a simple configuration. It can be made to emit simultaneously. As a result, efficient and highly accurate detection becomes possible.

  In one embodiment of the present invention, an i-th frequency (i is an integer satisfying 1 ≦ i ≦ n−1) of the first to n-th frequencies and a j-th higher frequency than the i-th frequency. As for the frequency (j is an integer satisfying 2 ≦ j ≦ n), the j-th frequency may be a non-integer multiple of the i-th frequency.

  In this way, since the j-th frequency does not become a harmonic of the i-th frequency, the influence of the frequency component of the harmonic on the received signal can be prevented.

  In the aspect of the invention, the frequency of the half-wave pulse may be higher than the highest frequency among the first frequency to the n-th frequency.

  In this way, it is possible to efficiently emit ultrasonic waves having the first to nth frequencies.

  In the aspect of the invention, the half-wave pulse may be any one of a half-wave rectangular wave, a half-wave triangular wave, and a half-wave sine wave.

  If it does in this way, the ultrasonic wave of the 1st-nth frequency can be radiate | emitted simultaneously by driving with the half wave pulse of one frequency.

  According to another aspect of the present invention, a reception unit that performs reception processing of a reception signal from the ultrasonic device includes the first frequency to the nth frequency included in a pass frequency band. 1 band-pass filter circuit to n-th band-pass filter circuit may be included.

  In this way, the first to nth bandpass filter circuits can separate and output desired frequency components including the first to nth frequencies from the received signal.

  In one embodiment of the present invention, a signal analyzing unit that performs frequency analysis based on output signals of the first to nth bandpass filter circuits may be included.

  In this way, by performing frequency analysis of the output signals of the first to nth band pass filter circuits, it is possible to analyze the frequency distribution of the echo signal by the ultrasonic waves of the first to nth frequencies. .

  In one aspect of the present invention, the signal analysis unit includes a first quadrature detector to an nth quadrature detection that quadrature-detects output signals of the first bandpass filter circuit to the nth bandpass filter circuit. An analysis result of the at least one Fourier transformer, and at least one Fourier transformer that performs frequency analysis based on a signal quadrature detected by the first to n-th quadrature detectors. You may have at least 1 arithmetic circuit which performs a calculation based on.

  In this way, only the frequency shift component can be extracted from the received signal by performing quadrature detection, so that it is possible to perform highly accurate frequency analysis.

  In the aspect of the invention, the signal analysis unit may perform frequency analysis for each output signal of the first band-pass filter circuit to the n-th band-pass filter circuit.

  In this way, it is possible to analyze the frequency distribution of the echo signal by the ultrasonic waves of each frequency for each of the first to nth frequencies.

  In the aspect of the invention, the signal analysis unit may include a first sample obtained from the first output signal to the nth output signal of the first bandpass filter circuit to the nth bandpass filter circuit. The frequency analysis may be performed based on data to n-th sample data.

  In this way, the number of data samples used for analysis can be increased, and the time response can be improved, so that efficient and highly accurate frequency analysis can be performed.

  In the aspect of the invention, the signal analysis unit may include a first normalization circuit to an nth normalization that normalizes output signals of the first bandpass filter circuit to the nth bandpass filter circuit. And the first normalization circuit to the nth normalization circuit perform a normalization process for converting a reception signal of the first frequency to the nth frequency into a signal of one reference frequency. The Fourier transformer may perform frequency analysis by combining signals normalized by the first normalization circuit to the nth normalization circuit.

  In this way, since frequency analysis can be performed by synthesizing standardized signals, it is possible to efficiently analyze the frequency distribution of echo signals by ultrasonic waves having different frequencies.

  According to another aspect of the present invention, a first ultrasonic element group to an nth ultrasonic element group having resonance characteristics of a frequency of a first frequency to an nth (n is an integer of 2 or more), Including a plurality of drive electrode lines wired along a direction and a plurality of common electrode lines wired along a second direction intersecting the first direction, the first ultrasonic element group to Each ultrasonic element group of the nth ultrasonic element group includes a plurality of ultrasonic element arrays arranged along the second direction, and each ultrasonic element array of the plurality of ultrasonic element arrays. Has a plurality of ultrasonic elements arranged along the first direction, and the first electrode of each of the plurality of ultrasonic elements is one of the plurality of drive electrode lines. The second electrode of each of the plurality of ultrasonic elements is connected to any one of the plurality of common electrode lines. Is the related to the ultrasound device.

  According to another aspect of the present invention, driving signals are supplied to a plurality of driving electrode lines to drive first to nth ultrasonic element groups having resonance characteristics of first to nth frequencies. In addition, ultrasonic waves having the first to nth frequencies can be emitted simultaneously.

  In another aspect of the present invention, the ultrasonic element provided for each opening of the plurality of openings includes a substrate having a plurality of openings arranged in an array, and the vibration film that closes the openings; A piezoelectric element portion provided on the vibration film, the piezoelectric element portion including a lower electrode provided on the vibration film, and a piezoelectric film provided to cover at least a part of the lower electrode. An upper electrode provided to cover at least a part of the piezoelectric film, the first electrode is one of the upper electrode and the lower electrode, and the second electrode is the upper electrode The other of the electrode and the lower electrode may be used.

  In this way, the ultrasonic elements having the piezoelectric film can be arranged on the substrate in an array.

  In another aspect of the present invention, the ultrasonic element having resonance characteristics of an i-th frequency (i is an integer satisfying 1 ≦ i ≦ n−1) among the first frequency to the n-th frequency. The length of the short side of the opening of the ultrasonic element having resonance characteristics of the j-th frequency (j is an integer satisfying 2 ≦ j ≦ n) higher than the i-th frequency. It may be longer.

  In this way, ultrasonic elements having resonance characteristics of the first to nth frequencies can be mixed and formed on the same substrate.

  Another aspect of the present invention relates to an ultrasonic probe including any of the processing apparatuses described above.

  Another aspect of the present invention relates to an ultrasonic probe including any of the ultrasonic devices described above.

  Another aspect of the present invention relates to an ultrasonic diagnostic apparatus including any of the processing apparatuses described above and a display unit that displays display image data.

1A and 1B are basic configuration examples of an ultrasonic element. Examples of half-wave square wave, half-wave triangle wave, and half-wave sine wave. FIGS. 3A, 3B, and 3C are frequency distributions of ultrasonic waves emitted when a half-wave rectangular wave is input. 4A, 4B, and 4C are frequency distributions of ultrasonic waves emitted when a half-wave sine wave is input. FIG. 5A, FIG. 5B, and FIG. 5C show the frequency distribution of ultrasonic waves emitted when a half-wave triangular wave is input. The structural example of an ultrasonic device. The structural example of a processing apparatus. 8A and 8B show first and second configuration examples of the receiving unit and the signal analyzing unit. FIG. 9A and FIG. 9B are diagrams for explaining flow velocity detection by the Doppler effect. 2 is a basic configuration example of an ultrasonic probe and an ultrasonic diagnostic apparatus. FIG. 11A and FIG. 11B are specific configuration examples of the ultrasonic diagnostic apparatus. FIG. 11C illustrates a specific configuration example of the ultrasonic probe.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

1. Ultrasonic Element FIGS. 1A and 1B show a basic configuration example of the ultrasonic element UE included in the ultrasonic apparatus of the present embodiment. The ultrasonic element UE of the present embodiment includes a vibration film (membrane, support member) MB and a piezoelectric element unit. The piezoelectric element portion includes a lower electrode (first electrode layer) EL1, a piezoelectric film (piezoelectric layer) PE, and an upper electrode (second electrode layer) EL2. Note that the ultrasonic element UE of the present embodiment is not limited to the configuration of FIG. 1, and various components such as omitting some of the components, replacing them with other components, and adding other components. Variations are possible.

  FIG. 1A is a plan view of an ultrasonic element UE formed on a substrate (silicon substrate) SUB, as viewed from a direction perpendicular to the substrate on the element formation surface side. FIG. 1B is a cross-sectional view showing a cross section along A-A ′ of FIG.

  The first electrode layer EL1 is formed of, for example, a metal thin film on the vibration film MB. As shown in FIG. 1A, the first electrode layer EL1 may be a wiring that extends to the outside of the element formation region and is connected to the adjacent ultrasonic element UE.

The piezoelectric film PE is formed of, for example, a PZT (lead zirconate titanate) thin film, and is provided so as to cover at least a part of the first electrode layer EL1. The material of the piezoelectric film PE is not limited to PZT. For example, lead titanate (PbTiO ₃ ), lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La) TiO ₃ ), etc. May be used.

  The second electrode layer EL2 is formed of, for example, a metal thin film, and is provided so as to cover at least a part of the piezoelectric film PE. As shown in FIG. 1A, the second electrode layer EL2 may be a wiring that extends outside the element formation region and is connected to the adjacent ultrasonic element UE.

The vibration film (membrane) MB is provided so as to close the opening OP by, for example, a two-layer structure of a SiO ₂ thin film and a ZrO ₂ thin film. The vibration film MB supports the piezoelectric film PE and the first and second electrode layers EL1 and EL2, and can vibrate according to the expansion and contraction of the piezoelectric film PE to generate ultrasonic waves.

  The cavity region CAV is formed by etching by reactive ion etching (RIE) or the like from the back surface (surface on which no element is formed) side of the silicon substrate SUB. Ultrasonic waves are radiated from the opening OP of the cavity region CAV.

  The lower electrode of the ultrasonic element UE is formed by the first electrode layer EL1, and the upper electrode is formed by the second electrode layer EL2. Specifically, a portion of the first electrode layer EL1 covered with the piezoelectric film PE forms a lower electrode, and a portion of the second electrode layer EL2 that covers the piezoelectric film PE forms an upper electrode. . That is, the piezoelectric film PE is provided between the lower electrode and the upper electrode.

  The piezoelectric film PE expands and contracts in the in-plane direction when a voltage is applied between the lower electrode and the upper electrode, that is, between the first electrode layer EL1 and the second electrode layer EL2. One surface of the piezoelectric film PE is joined to the vibration film MB via the first electrode layer EL1, but the second electrode layer EL2 is formed on the other surface, but on the second electrode layer EL2. No other layers are formed. Therefore, the vibration film MB side of the piezoelectric film PE is not easily expanded and contracted, and the second electrode layer EL2 side is easily expanded and contracted. Therefore, when a voltage is applied to the piezoelectric film PE, a convex bend is generated on the cavity region CAV side, and the vibration film MB is bent. By applying an AC voltage to the piezoelectric film PE, the vibration film MB vibrates in the film thickness direction, and an ultrasonic wave is emitted from the opening OP by the vibration of the vibration film MB. The voltage applied to the piezoelectric film PE is, for example, 10 to 30 V, and the frequency is, for example, 1 to 10 MHz.

  The ultrasonic element UE has a resonance characteristic determined by the length LOP of the short side of the opening OP. The longer the short side length LOP of the opening OP, the lower the resonance frequency, and the shorter the short side length LOP of the opening OP, the higher the resonance frequency. The first to n-th ultrasonic elements having resonance frequencies of the first to n-th (n is an integer of 2 or more) frequencies f1 to fn are i-th (i is an integer satisfying 1 ≦ i ≦ n−1). The length LOPi of the short side of the opening OP of the i-th ultrasonic element having the resonance characteristic of the frequency fi is the j-th frequency j (j is an integer satisfying 2 ≦ j ≦ n) higher than the i-th frequency fi. This is longer than the length LOPj of the short side of the opening OP of the j-th ultrasonic element having the following resonance characteristics. That is, the resonance frequency of the i-th ultrasonic element is fi, the resonance frequency of the j-th ultrasonic element is fj (fi <fj), and the length of the short side of the opening OP of the i-th and j-th ultrasonic elements. Is LOPi> LOPj, where LOPi> LOPj.

  The ultrasonic element UE having the resonance characteristic of the i-th frequency means that the ultrasonic wave emitted from the ultrasonic element UE has a peak at the i-th frequency.

  As will be described later, in the ultrasonic device 100 of the present embodiment, ultrasonic elements having different resonance frequencies are mixed on one substrate by providing ultrasonic elements having different lengths LOP of the short sides of the opening OP. Can be arranged.

  A half-wave pulse can be used as a signal (driving signal) applied to the piezoelectric film PE of the ultrasonic element UE. As the half-wave pulse, any one of a half-wave rectangular wave, a half-wave triangular wave, and a half-wave sine wave can be used. Alternatively, it is desirable to use any one of a half-wave rectangular wave, a half-wave triangle wave, and a half-wave sine wave as the half-wave pulse.

  The signal waveform of the half-wave pulse is a signal waveform composed of one rising portion where the voltage changes from the reference voltage to the maximum voltage and one falling portion where the voltage changes from the maximum voltage to the reference voltage. However, the voltage change at the rising portion is not always monotonically increasing, and the voltage change at the falling portion is not always monotonically decreasing. For example, the rising portion may include overshoot, and the falling portion may include undershoot.

  FIG. 2 shows examples of half-wave pulses, half-wave triangle waves, and half-wave sine waves as half-wave pulses. As shown in FIG. 2, the half-wave pulse is composed of a signal for ½ period. By using such a half-wave pulse as a drive signal, a plurality of ultrasonic elements having different resonance frequencies can be driven by a half-wave pulse having the same frequency. This is because these half-wave pulses have a wide frequency component.

  FIG. 3A, FIG. 3B, and FIG. 3C show the frequency distribution (frequency spectrum) of ultrasonic waves emitted when a half-wave rectangular wave is input. The resonance frequency of the ultrasonic element is 1 MHz. FIG. 3A shows a case where a half-wave rectangular wave of 0.5 MHz is input, but the output is remarkably reduced in the vicinity of the resonance frequency of 1 MHz. In addition, a sub-peak of output is seen around 0.5 MHz. On the other hand, FIG. 3B and FIG. 3C show the case where a 1 MHz and 1.5 MHz half-wave rectangular wave is input, respectively, but no decrease in output is observed near the resonance frequency of 1 MHz.

  FIG. 4A, FIG. 4B, and FIG. 4C show frequency distributions of ultrasonic waves emitted when a half-wave sine wave is input. The resonance frequency of the ultrasonic element is 1 MHz. FIG. 4A shows a case where a 0.5 MHz half-wave sine wave is input, but the output is distributed even in a frequency region lower than the resonance frequency of 1 MHz. On the other hand, FIG. 3B and FIG. 3C show the case where a half sine wave of 1 MHz and 1.5 MHz is input, respectively, but a sharp peak is seen in the vicinity of the resonance frequency of 1 MHz.

  FIG. 5A, FIG. 5B, and FIG. 5C show frequency distributions of ultrasonic waves emitted when a half-wave triangular wave is input. The resonance frequency of the ultrasonic element is 1 MHz. FIG. 4A shows a case where a 0.5 MHz half-wave triangular wave is input, but the output is distributed even in a frequency region lower than the resonance frequency of 1 MHz. On the other hand, FIG. 3B and FIG. 3C show the case where a half sine wave of 1 MHz and 1.5 MHz is input, respectively, but a sharp peak is seen in the vicinity of the resonance frequency of 1 MHz.

  From the above, when a half-wave pulse having a frequency lower than the resonance frequency of the ultrasonic element is used, the frequency spectrum of the emitted ultrasonic wave becomes complicated. On the other hand, when a half-wave pulse having a frequency higher than the resonance frequency of the ultrasonic element is used, the frequency spectrum of the emitted ultrasonic wave has a desirable shape. Therefore, when driving a plurality of ultrasonic elements having different resonance frequencies with the same half-wave pulse, it is desirable to use a half-wave pulse with a frequency higher than the highest resonance frequency.

2. Ultrasonic Device FIG. 6 shows a configuration example of the ultrasonic device 100 of the present embodiment. The ultrasonic device 100 of this configuration example includes first to n-th (n is an integer of 2 or more) ultrasonic element groups UEG1 to UEGn, a plurality of drive electrode lines DL11, DL12, DL13,. Lines CL1 to CLm (m is an integer of 2 or more) are included. FIG. 6 shows a case where m = 8 and n = 4 as an example, but other values may be used. Note that the ultrasonic device 100 of the present embodiment is not limited to the configuration of FIG. 6, and various components such as omitting some of the components, replacing them with other components, and adding other components. Variations are possible.

  The first to nth ultrasonic element groups UEG1 to UEGn have resonance frequencies of the first to nth frequencies. Each ultrasonic element group includes a plurality of ultrasonic element arrays (for example, UEC11, UEC12, UEC13) arranged along the second direction D2. Each ultrasonic element row of the plurality of ultrasonic element rows includes a plurality of ultrasonic elements arranged along the first direction D1. For example, the first ultrasonic element group UEG1 includes three ultrasonic element rows UEC11, UEC12, and UEC13. The ultrasonic element row UEC11 includes eight ultrasonic elements UE arranged along the first direction D1. The ultrasonic elements included in the three ultrasonic element rows UEC11, UEC12, and UEC13 have resonance characteristics of the first frequency. In FIG. 6, each ultrasonic element group includes three ultrasonic element arrays, but the number of ultrasonic element arrays is not limited to this.

  Assuming that the resonance frequencies of the first to nth ultrasonic element groups UEG1 to UEGn are f1 to fn, if f1 <f2 <f3 <... <fn, then LOP1> LOP2> LOP3>. LOPn. Here, LOPk (k is an integer satisfying 1 ≦ k ≦ n) is the length of the short side of the opening OP of the ultrasonic element UE included in the kth ultrasonic element group UEGk.

  Of the first to n-th frequencies, the i-th frequency i (i is an integer satisfying 1 ≦ i ≦ n−1) and the j-th higher than the i-th frequency (j is an integer satisfying 2 ≦ j ≦ n) The frequency fj is set so that the j-th frequency fj is a non-integer multiple of the i-th frequency fi. For example, when n = 4, f1 = 1 MHz, f2 = 1.5 MHz, f3 = 3.5 MHz, and f4 = 5.5 MHz. By doing in this way, the harmonic component contained in the ultrasonic wave emitted from one ultrasonic element group overlaps with the ultrasonic wave emitted from another ultrasonic element group having the same resonance frequency as the harmonic. Can be prevented. Further, it is possible to prevent an imaginary frequency component such as twice or three times the actual reception frequency generated at the time of sampling of the A / D converter from overlapping the original reception signal.

  The plurality of drive electrode lines DL11, DL12, DL13,... Are wired along the first direction D1. The first electrode of each ultrasonic element UE is connected to one of the plurality of drive electrode lines. For example, in FIG. 6, the first electrodes of the eight ultrasonic elements included in the ultrasonic element row UEC11 of the first ultrasonic element group UEG1 are connected to the drive electrode line DL11. Similarly, the first electrodes of the eight ultrasonic elements included in the ultrasonic element row UEC12 are connected to the drive electrode line DL12.

  In a transmission period in which ultrasonic waves are emitted, a drive signal output from the processing device 200 described later is supplied to each ultrasonic element via the drive electrode lines DL11, DL12,. Further, during the reception period for receiving the ultrasonic echo signal, the reception signal from each ultrasonic element is output via the drive electrode lines DL11, DL12,.

  The first to m-th common electrode lines CL1 to CLm (a plurality of common electrode lines in a broad sense) are wired along the second direction D2. The second electrode of each ultrasonic element UE is connected to one of the first to mth common electrode lines CL1 to CLm.

  The first to mth common electrode lines CL1 to CLm are commonly connected to the common voltage line CML, and the common voltage VCOM is supplied to the common voltage line CML. The common voltage VCOM may be a constant DC voltage, and may not be 0 V, that is, the ground potential (ground potential).

  According to the ultrasonic device 100 of the present embodiment, since a plurality of ultrasonic elements having different resonance frequencies can be provided, ultrasonic waves having different frequencies can be emitted simultaneously. Furthermore, ultrasonic elements having different resonance frequencies can be simultaneously driven by a drive signal having one frequency.

3. Processing Device FIG. 7 shows a configuration example of the processing device 200 of this embodiment. The processing apparatus 200 of this configuration example is a processing apparatus that performs ultrasonic transmission and reception processing on the ultrasonic device 100, and includes a transmission unit 210, a control unit 220, a switch unit 230, and a reception unit 240. Note that the processing apparatus 200 of the present embodiment is not limited to the configuration in FIG. 7, and various modifications such as omitting some of the components, replacing them with other components, and adding other components. Implementation is possible.

  The transmission unit 210 transmits the first to nth drive signals VDR1 to VDRn (half-wave pulses) to the first to nth ultrasonic element groups UEG1 to UEGn of the ultrasonic device 100 via the switch unit 230. In a broad sense, a drive signal) is output. As the half-wave pulse, any one of a half-wave rectangular wave, a half-wave triangular wave, and a half-wave sine wave can be used. Alternatively, it is desirable to use any one of a half-wave rectangular wave, a half-wave triangle wave, and a half-wave sine wave as the half-wave pulse. The drive signals VDR1 to VDRn are half-wave pulses having the same frequency, and as described above, it is desirable to use half-wave pulses having a frequency higher than the highest resonance frequency. By doing so, it is not necessary to generate a drive signal having a different frequency for each resonance frequency of the first to nth ultrasonic element groups UEG1 to UEGn, so that the configuration of the transmission unit 210 can be simplified.

  The reception unit 240 performs reception processing of the reception signals VR <b> 1 to VDRn from the ultrasonic device 100 via the switch unit 230. Specifically, amplification of the received signal, gain setting, frequency setting, A / D conversion (analog / digital conversion), and the like are performed and output to the signal analysis unit 250. The configuration of the receiving unit 240 will be described later.

  The control unit 220 controls the transmission unit 210, the reception unit 240, the switch unit 230, and the signal analysis unit 250. Specifically, generation of the drive signals VDR1 to VDRn and control of output processing are performed for the transmission unit 210, reception processing of the reception signals VR1 to VRn is controlled for the reception unit 240, and the switch unit 230 is controlled. To control switching between transmission and reception. The control unit 220 can be realized by, for example, an FPGA (Field-Programmable Gate Array).

  The switch unit 230 includes switch circuits SW1 to SWn, and performs transmission / reception switching processing based on the control of the control unit 220. Specifically, for example, SW1 outputs the drive signal VDR1 from the transmission unit 210 to the first ultrasonic element group UEG1 in the transmission period, and from the first ultrasonic element group UEG1 in the reception period. The received signal VR1 is output to the receiving unit 240.

  The signal analysis unit 250 performs frequency analysis based on the signal from the reception unit 240 and outputs an analysis result (for example, average flow velocity, maximum flow velocity, etc.).

  FIGS. 8A and 8B show first and second configuration examples of the receiving unit 240 and the signal analyzing unit 250 of the present embodiment. The receiving unit 240 and the signal analyzing unit 250 of the present embodiment are not limited to the configurations shown in FIGS. 8A and 8B, and some of the components are omitted or replaced with other components. Various modifications such as adding other components are possible.

  The receiving unit 240 shown in FIG. 8A includes an amplifier circuit AMP and first to fourth bandpass filter circuits BPF1 to BPF4. The signal analysis unit 250 includes first to fourth quadrature detectors QDT1 to QDT4, first to fourth Fourier transformers FFT1 to FFT4, and first to fifth arithmetic circuits CLC1 to CLC5.

  The amplifier circuit AMP amplifies the reception signal VR from each ultrasonic element of the ultrasonic device 100 and outputs the amplified signal to the bandpass filter circuits BPF1 to BPF4.

  The pass frequency bands of the first to fourth bandpass filter circuits BPF1 to BPF4 include a first frequency to a fourth (nth in a broad sense) frequencies f1 to f4. For example, in the case of f1 = 1 MHz, f2 = 1.5 MHz, f3 = 3.5 MHz, f4 = 5.5 MHz, BPF1 is 1 MHz ± 10 kHz, BPF2 is 1.5 MHz ± 10 kHz, BPF3 is 3.5 MHz ± 10 kHz, and BPF4 is It has a pass frequency band of 5.5 MHz ± 10 kHz. By doing so, for example, the frequency shift due to the Doppler effect corresponding to the flow velocity of blood flowing in the blood vessel is about several kHz, so the frequency shift components corresponding to the frequencies f1 to f4 are separated from the received signal. It can be taken out.

  The quadrature detectors QDT1 to QDT4 perform quadrature detection on the output signals from the bandpass filter circuits BPF1 to BPF4. By performing quadrature detection, only the frequency shift component can be extracted.

  Fourier transformers FFT1 to FFT4 perform frequency analysis of output signals from quadrature detectors QDT1 to QDT4. The arithmetic circuits CLC1 to CLC4 calculate an average flow velocity, a minimum flow velocity, a maximum flow velocity, and the like based on the analysis results of the Fourier transformers FFT1 to FFT4. The arithmetic circuit CLC5 further averages the four sets of average flow velocity, minimum flow velocity, and maximum flow velocity calculated by the arithmetic circuits CLC1 to CLC4, and outputs a final average flow velocity, minimum flow velocity, maximum flow velocity, and the like.

  The signal analysis unit 250 performs frequency analysis based on the first to fourth sample data obtained from the first to fourth output signals of the first to fourth bandpass filter circuits BPF1 to BPF4. The ultrasonic waves of the first to fourth frequencies are simultaneously emitted by the drive signal of one half-wave pulse, the reception signals of the first to fourth frequencies are received, and the first to fourth samples are received from these reception signals. Data is obtained.

  As described above, according to the first configuration example of the signal analysis unit 250, echo signals having different frequencies are simultaneously received, signal analysis is performed for each frequency, and average flow velocity, minimum flow velocity, maximum flow velocity, and the like are calculated. The final analysis result can be obtained by averaging them. As a result, the number of signal samples used for analysis can be increased, and the time response can be improved, so that efficient and highly accurate analysis becomes possible.

  In the flow velocity detection by Fourier analysis, for example, about 1000 samples are required for Fourier analysis. If the time taken to acquire one sample is 100 μs, 100 ms is required for one flow rate detection. Although it is possible to improve the time response by increasing the sampling frequency, there is a demerit that the circuit load increases. According to the processing apparatus 200 of the present embodiment, ultrasonic waves having different frequencies can be emitted simultaneously, and echo signals of the respective frequencies can be received and analyzed. For example, ultrasonic waves having the first to fourth frequencies can be received. If used, the number of samples can be increased fourfold.

  The receiving unit 240 shown in FIG. 8B includes an amplifier circuit AMP and first to fourth bandpass filter circuits BPF1 to BPF4. The signal analysis unit 250 includes first to fourth quadrature detectors QDT1 to QDT4, first to fourth normalization circuits NRM1 to NRM4, Fourier transformers FFT, and CLC.

  Since the amplifier circuit AMP, the bandpass filter circuits BPF1 to BPF4, and the quadrature detectors QDT1 to QDT4 are the same as those in the first configuration example, detailed description thereof is omitted.

  The normalization circuits NRM1 to NRM4 normalize output signals from the quadrature detectors QDT1 to QDT4 based on a predetermined frequency (reference frequency). This normalization process is performed as follows. When the reference frequency is fref and the frequency of the received signal is fk (k = 1, 2, 3, 4), the time t of the received signal is converted to t ′ defined by t ′ = fk / fref × t. Sampling (resampling) is performed. By doing in this way, the frequency analysis of the received signal of different frequencies f1-f4 can be carried out with one Fourier-transformer FFT. Note that the reference frequency fref may be one of the reception frequencies. For example, when the first frequency f1 = 1 MHz is used as the reference frequency, the first normalization circuit NRM1 can be omitted.

  The Fourier transformer FFT performs frequency analysis by synthesizing signals normalized by the normalization circuits NRM1 to NRM4. The arithmetic circuit CLC calculates an average flow velocity, a minimum flow velocity, a maximum flow velocity, and the like based on the analysis result of the Fourier transformer FFT.

  As described above, according to the second configuration example of the signal analysis unit 250, frequency analysis is performed with one Fourier transformer FFT for different frequencies by performing the normalization process, and the average flow velocity, the minimum flow velocity, the maximum flow velocity, and the like. Therefore, more efficient and accurate analysis becomes possible.

  FIG. 9A and FIG. 9B are diagrams for explaining flow velocity detection by the Doppler effect. As shown in FIG. 9A, an ultrasonic wave having a frequency f is emitted from an ultrasonic probe 300 including the ultrasonic device 100 and the processing apparatus 200. This ultrasonic wave is reflected by a liquid (for example, blood) flowing at a flow velocity v and is received as an echo signal by the ultrasonic probe 300. At this time, the frequency shifts to f + Δf due to the Doppler effect. This frequency shift Δf is given by the following equation, where θ is the angle formed by the direction of the flow velocity v and the outgoing direction of the ultrasonic wave, and c is the velocity of the ultrasonic wave in the blood.

Δf = 2 · f · cos θ · v / c (1)
Since the actual blood flow velocity is distributed with a certain width, the frequency shift Δf is also detected with a certain width. For example, as shown in FIG. 9B, the detected frequency shift Δf is distributed in the range of Δf1 to Δf3, and has a peak at Δf2. The minimum flow velocity can be calculated from Δf1, the average flow velocity from Δf2, and the maximum flow velocity from Δf3, respectively, using Equation (1).

  As described above, according to the ultrasonic device 100 and the processing apparatus 200 of the present embodiment, by driving the ultrasonic device 100 with a half-wave pulse of one frequency, a plurality of different frequencies can be obtained with a simple configuration. Since sound waves can be emitted simultaneously, the number of samples used for analysis can be increased, and time response can be improved. As a result, efficient and highly accurate flow rate detection and the like become possible.

4). Ultrasonic Probe and Ultrasonic Diagnostic Device FIG. 10 shows a basic configuration example of the ultrasonic probe 300 and the ultrasonic diagnostic device (blood flow measuring device) 400 of the present embodiment. The ultrasonic probe 300 includes an ultrasonic device 100 and a processing apparatus 200. The ultrasonic diagnostic apparatus 400 includes an ultrasonic probe 300, a main control unit 310, a processing unit 320, a UI (user interface) unit 330, and a display unit 340.

  The main control unit 310 performs transmission / reception control of ultrasonic waves with respect to the ultrasonic probe 300 and controls the processing unit 320 such as display processing of analysis results. Note that a part of the control performed by the main control unit 310 may be performed by the control unit 220 of the processing apparatus 200, and a part of the control performed by the control unit 220 is performed by the main control unit 310 of the ultrasonic diagnostic apparatus 400. You may go.

  The processing unit 320 receives the analysis result from the signal analysis unit 250 and performs necessary display processing, generation of display image data, and the like.

  A UI (user interface) unit 330 outputs necessary commands (commands) to the main control unit 310 based on an operation (for example, a touch panel operation) performed by a user.

  The display unit 340 is a liquid crystal display, for example, and displays the display image data from the processing unit 320.

  FIG. 11A and FIG. 11B show a specific configuration example of the ultrasonic diagnostic apparatus (blood flow measuring apparatus) 400 of the present embodiment. FIG. 11A shows a portable ultrasonic diagnostic apparatus 400, and FIG. 11B shows a wristband type ultrasonic diagnostic apparatus 400.

  A portable ultrasonic diagnostic apparatus 400 in FIG. 11A includes an ultrasonic probe 300, a cable CB, and an ultrasonic diagnostic apparatus main body 410. The ultrasonic probe 300 is connected to the ultrasonic diagnostic apparatus main body 410 by a cable CB. The ultrasonic diagnostic apparatus main body 410 includes a display unit 340 that displays a diagnosis result (display image data).

  A wristband type ultrasonic diagnostic apparatus 400 in FIG. 11B includes an ultrasonic probe 300 and an ultrasonic diagnostic apparatus main body 410. The ultrasonic diagnostic apparatus main body 410 includes a display unit 340 that displays a diagnosis result (display image data). The ultrasonic probe 300 and the ultrasonic diagnostic apparatus main body 410 can be stored in an integral casing.

  FIG. 11C shows a specific configuration example of the ultrasonic probe 300 of the present embodiment. The ultrasonic probe 300 includes a probe head 301 and a probe main body 302, and the probe head 301 can be attached to and detached from the probe main body 302 as shown in FIG.

  The probe head 301 includes an ultrasonic device 100, a support member SUP, a contact member 130 that contacts the subject, a protective member (protective film) PF that protects the ultrasonic device 100, a connector CNa, and a probe housing 140. The ultrasonic device 100 is provided between the contact member 130 and the support member SUP.

  The probe main body 302 includes a processing device 201 and a probe main body side connector CNb. The processing device 201 includes a driving device 200 and a receiving unit 240. The probe main body side connector CNb is connected to the probe head side connector CNa. The probe main body 302 is connected to the ultrasonic diagnostic apparatus main body by a cable CB.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. The configurations and operations of the processing apparatus, the ultrasonic device, the ultrasonic probe, and the ultrasonic diagnostic apparatus are not limited to those described in this embodiment, and various modifications can be made.

100 ultrasonic device, 130 contact member, 140 probe housing,
200 processing unit, 210 transmission unit, 220 control unit,
230 switch unit, 240 reception unit, 250 signal analysis unit,
300 ultrasonic probe, 301 probe head, 302 probe body,
310 main control unit, 320 processing unit, 330 UI unit,
340 display unit, 400 ultrasonic diagnostic apparatus, 410 ultrasonic diagnostic apparatus main body,
UEG1 to UEGn 1st to nth ultrasonic element groups, VDR1 to VDRn drive signals,
VR1 to VRn received signal

Claims (16)

An ultrasonic device processing apparatus comprising:
A transmission unit that outputs a drive signal to the ultrasonic device;
A control unit for controlling the transmission unit,
The ultrasonic device is
A first ultrasonic element group to an nth ultrasonic element group having resonance characteristics of a frequency from a first frequency to an nth (n is an integer of 2 or more);
The transmitter is
A processing apparatus that outputs a drive signal of a half-wave pulse as the drive signal to the first to nth ultrasonic element groups. In claim 1,
Of the first frequency to the nth frequency, the i-th frequency (i is an integer satisfying 1 ≦ i ≦ n−1) and the jth frequency higher than the i-th frequency (j is 2 ≦ j ≦ n). The processing apparatus is characterized in that the j-th frequency is a non-integer multiple of the i-th frequency. In claim 1 or 2,
The frequency of the half wave pulse is
The processing apparatus having a frequency higher than a highest frequency among the first frequency to the nth frequency. In any one of Claims 1 thru | or 3,
The half wave pulse is
A processing apparatus characterized by being one of a half-wave rectangular wave, a half-wave triangular wave, and a half-wave sine wave. In any one of Claims 1 thru | or 4,
A reception unit that performs reception processing of a reception signal from the ultrasonic device;
The receiver is
A processing apparatus comprising: a first band-pass filter circuit to an n-th band-pass filter circuit in which the first frequency to the n-th frequency are included in a pass frequency band. In claim 5,
A processing apparatus comprising: a signal analysis unit that performs frequency analysis based on output signals from the first band-pass filter circuit to the n-th band-pass filter circuit. In claim 6,
The signal analysis unit
A first quadrature detector to an nth quadrature detector for quadrature detection of an output signal of the first bandpass filter circuit to the nth bandpass filter circuit;
At least one Fourier transform that performs frequency analysis based on signals quadrature detected by the first quadrature detector to the nth quadrature detector;
A processing apparatus comprising: at least one arithmetic circuit that performs an operation based on an analysis result of the at least one Fourier transformer. In claim 6 or 7,
The signal analysis unit
A processing apparatus that performs frequency analysis for each output signal of the first band-pass filter circuit to the n-th band-pass filter circuit. In claim 8,
The signal analysis unit
The frequency analysis based on the first sample data to the n-th sample data obtained from the first output signal to the n-th output signal of the first band-pass filter circuit to the n-th band-pass filter circuit. The processing apparatus characterized by performing. In claim 7,
The signal analysis unit
A first normalization circuit to an nth normalization circuit for normalizing output signals of the first bandpass filter circuit to the nth bandpass filter circuit;
The first normalization circuit to the nth normalization circuit are:
Performing a normalization process of converting the received signal of the first frequency to the nth frequency into a signal of one reference frequency;
The Fourier transformer is
A processing apparatus for performing frequency analysis by synthesizing signals standardized by the first normalization circuit to the nth normalization circuit. A first ultrasonic element group to an nth ultrasonic element group having resonance characteristics of a frequency of a first frequency to an nth frequency (n is an integer of 2 or more);
A plurality of drive electrode lines wired along the first direction;
A plurality of common electrode lines wired along a second direction intersecting the first direction,
Each ultrasonic element group of the first ultrasonic element group to the nth ultrasonic element group is:
A plurality of ultrasonic element rows arranged along the second direction;
Each ultrasonic element row of the plurality of ultrasonic element rows is,
A plurality of ultrasonic elements arranged along the first direction;
The first electrode of each ultrasonic element of the plurality of ultrasonic elements is connected to one of the plurality of drive electrode lines,
The ultrasonic device, wherein the second electrode of each of the plurality of ultrasonic elements is connected to one of the plurality of common electrode lines. In claim 11,
Including a substrate having a plurality of openings arranged in an array;
The ultrasonic element provided for each opening of the plurality of openings,
A vibrating membrane that closes the opening;
A piezoelectric element portion provided on the vibrating membrane;
The piezoelectric element portion is
A lower electrode provided on the vibrating membrane;
A piezoelectric film provided to cover at least a part of the lower electrode;
An upper electrode provided to cover at least a part of the piezoelectric film,
The first electrode is one of the upper electrode and the lower electrode;
The ultrasonic device according to claim 2, wherein the second electrode is the other of the upper electrode and the lower electrode. In claim 12,
The length of the short side of the opening of the ultrasonic element having the resonance characteristic of the i-th (i is an integer satisfying 1 ≦ i ≦ n−1) out of the first frequency to the n-th frequency. Is longer than the length of the short side of the opening of the ultrasonic element having the resonance characteristic of the j-th frequency (j is an integer satisfying 2 ≦ j ≦ n) higher than the i-th frequency. device.   An ultrasonic probe comprising the processing apparatus according to claim 1.   An ultrasonic probe comprising the ultrasonic device according to claim 11. A processing apparatus according to any one of claims 1 to 10,
An ultrasonic diagnostic apparatus comprising: a display unit that displays display image data.

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