JP2019195495A - Blood vessel diameter measuring system - Google Patents

Abstract

To provide a blood vessel diameter measuring system that has an ultrasonic probe capable of measuring a blood vessel diameter accurately with a good reproducibility and having a superior wearable property.SOLUTION: A blood vessel diameter measuring system for measuring a blood vessel diameter of a living body by a pulse-echo method includes: an ultrasonic probe AP having a transmitter-receiver 2 for oscillating an ultrasound by applying a pulse voltage to a piezoelectric element 22 of an array form, and receiving a reflected wave; and a measuring instrument body for measuring the blood vessel diameter. The probe is connected with the main body in a communicating manner. The system further includes a silicon substrate 3 assuming the fitting direction of the probe to be a bottom and forming a silicon through-electrode 31 penetrating vertically. The system is mounted with a drive circuit 41, a power source, an amplifier circuit 43 and an A/D conversion circuit. The system is connected to a first electrode 21 with which a lower surface of each piezoelectric element is brought into contact and a second electrode 25 with which an upper surface is brought into contact through an electrode, respectively. A main body of the system is provided with control means for controlling the drive circuit and measuring the blood vessel diameter, and notification means for notifying a user of the blood vessel diameter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blood vessel diameter measuring system for measuring a blood vessel diameter of a living body by a pulse echo method.

  This type of blood vessel diameter measuring system is known from Patent Document 1, for example. This includes an ultrasonic probe and a measuring device main body that are communicably connected by wire or wirelessly. An ultrasonic probe detachably attached to a living body has a plurality of piezoelectric elements arranged in an array on the same plane, and applies a pulse voltage to each piezoelectric element to oscillate ultrasonic waves toward a blood vessel. A transmission / reception unit (ultrasonic transducer unit) that receives a reflected wave that collides with a blood vessel and reflects, a drive circuit and a communication circuit provided on the upper side of the transmission / reception unit, with the mounting direction with respect to a living body being downward, and these drive circuits, A film battery for supplying power to the communication circuit. On the other hand, the measuring instrument body includes a reflected wave receiving unit that receives the reflected wave transmitted from the ultrasonic probe, an amplification circuit that amplifies the reflected wave received by the reflected wave receiving unit, and the amplified reflected wave as a digital signal. An A / D conversion circuit for converting the signal into a digital signal, a control means for calculating a blood vessel diameter by processing a digital signal, and a display means for displaying the measured blood vessel diameter. When such a configuration is adopted, the transmission path from the reflected wave received by the transmitter / receiver of the ultrasonic probe to the digital signal after being amplified by the amplifier circuit of the measuring instrument main body is long, and is easily affected by noise. There is a problem, and this causes a decrease in the measurement accuracy of the blood vessel diameter.

  In addition, in the above conventional example, the above-described circuits including the circuit on the measuring instrument main body side are created on the upper side of the transmission / reception unit with a dedicated IC, and a system unit formed by mounting these ICs in a bare chip is mounted on a living body. It has also been proposed that the function of the measuring instrument main body excluding the display function is integrated into the ultrasonic probe to be mounted on the ultrasonic probe side, and only the measurement result is transmitted to the display element for display (Patent Document 1, Patent Document 1). 9 to 11). Here, when an ultrasonic wave oscillated from each piezoelectric element collides with a blood vessel and is reflected, the frequency of the reflected wave is usually about 20 MHz. For this reason, if a series of processing from the oscillation of the ultrasonic wave to the measurement of the blood vessel diameter is performed on the ultrasonic probe side, the control load is large and the power consumption is also large. For this reason, there is a problem that not only a battery with a large capacity is required, but also the amount of heat generated during measurement increases.

  By the way, since a person using this type of blood vessel diameter measurement system includes an elderly person, it is preferable that the ultrasound probe is lightweight in consideration of comfort when the ultrasound probe is worn for the elderly person. Moreover, it should not be uncomfortable during the measurement. If the function of the measuring instrument body is integrated on the ultrasonic probe side and a large-capacity battery is used as in the conventional example, the weight cannot be reduced, and the amount of heat generated during measurement increases. There is also a risk that the user may feel uncomfortable.

JP 2006-51105 A

  An object of the present invention is to provide a blood vessel diameter measuring system having an ultrasonic probe that can measure a blood vessel diameter with high accuracy and reproducibility and has excellent wearability. is there.

  In order to solve the above problems, a blood vessel diameter measuring system of the present invention for measuring a blood vessel diameter of a living body by a pulse echo method has a plurality of piezoelectric elements arranged in an array on the same plane, and each piezoelectric element is An ultrasonic probe having a transmission / reception unit that receives a reflected wave reflected from a blood vessel by oscillating an ultrasonic wave toward a blood vessel by applying a pulse voltage, and measuring the diameter of the blood vessel by analyzing the received reflected wave A silicon substrate on which an ultrasonic probe and a measuring instrument body are connected to be communicably connected to each other, and the ultrasonic probe is formed with a silicon penetrating electrode penetrating in a vertical direction with a mounting direction with respect to a living body facing downward. A drive circuit for selectively applying a pulse voltage to each piezoelectric element on the silicon substrate, a power supply for supplying power to the drive circuit, an amplifier circuit for amplifying the received reflected wave, and the amplified circuit An A / D conversion circuit that converts a radiation wave into a digital signal is mounted, and is connected to a first electrode that is in contact with the lower surface of each piezoelectric element and a second electrode that is in contact with the upper surface via a silicon through electrode. The measuring device main body is provided with control means for controlling the drive circuit and processing the digital signal to measure the blood vessel diameter, and notifying means for notifying the measured blood vessel diameter.

  According to the present invention, since the transmission path until the reflected wave received by the transmission / reception unit is amplified becomes as short as possible, it is difficult to be affected by noise, and the blood vessel diameter is accurately and reproducibly measured. Can do. Also, on the ultrasonic probe side, it is limited to only the function of oscillating the ultrasonic wave and amplifying the received reflected wave and converting it to a digital signal. There are not so many. As a result, the ultrasonic probe is light in weight and has excellent wearability without causing problems such as discomfort to the user during measurement.

  In addition, according to the present invention, it is possible to reduce the influence of noise when driving a plurality of piezoelectric elements arranged in an array at high speed signal switching, improving resolution by ultrasonic beam convergence, and reflecting waves (reflected waves). Echo) It is expected that measurement point sensitivity at the time of reception will be improved, and that measurement and imaging in a deep and wide range will be possible by driving a plurality of piezoelectric elements arranged in an array in a phased array. A circuit that performs high-speed signal switching for the above-described purpose can be similarly mounted on the silicon substrate.

The fragmentary sectional view of the ultrasonic probe which constitutes the blood vessel diameter measuring system of the embodiment of the present invention. The schematic block diagram explaining the function of an ultrasonic probe and a measuring device main body. (A)-(e) is sectional drawing which each shows the manufacturing process of the ultrasonic probe shown in FIG. (A) And (b) is sectional drawing which each shows the manufacturing process of the ultrasonic probe shown in FIG.

  Hereinafter, a blood vessel diameter measurement system according to an embodiment of the present invention will be described with reference to the drawings, taking as an example the case of measuring a blood vessel diameter of a living body by a pulse echo method.

  1 and 2, MS is a blood vessel diameter measurement system. The blood vessel diameter measuring system MS includes an array-type ultrasonic probe AP and a measuring device main body MB that are connected to be communicably wired or wirelessly.

  The ultrasonic probe AP includes an acoustic matching layer 1, a transmission / reception unit 2, and a silicon substrate 3. The ultrasonic probe AP is attached to a predetermined position of the wrist W that measures the diameter of the blood vessel B of the wrist radial artery as a measurement target. In the following, terms indicating directions such as up and down are based on the mounting posture of the ultrasonic probe AP shown in FIG.

  The acoustic matching layer 1 matches the acoustic impedance of a living body and the acoustic impedance of a piezoelectric element 22 as an ultrasonic element described later. For example, the acoustic matching layer 1 is made of polyimide, polyvinylidene fluoride, polyvinyl chloride, polyurethane, parylene, or polyurea. It is formed of one selected material, and its thickness is set in the range of 10 μm to 50 μm.

  The transmission / reception unit 2 is applied with a driving voltage (pulse voltage) and a first electrode film 21 formed on the acoustic matching layer 1 and in contact with a lower surface (one main surface) 22a of each piezoelectric element 22 described later. The piezoelectric element 22 is laminated on the acoustic matching layer 1 and the first electrode film 21, and oscillates ultrasonic waves toward the blood vessel B and receives reflected waves that collide with the blood vessel B and reflect. A first dry film resist 23 having a first opening 23a that surrounds the piezoelectric element 22, and a top surface 22b of the piezoelectric element 22 that is partially laminated on the first dry film resist 23. A second opening 24a that is exposed to light, a second dry film resist 24 that sandwiches the piezoelectric element 22 between the peripheral edge portion of the second opening 24a and the first electrode film 21, and each piezoelectric element 22 Top surface (the other Surface) 22b is constituted by the second electrode film 25 in contact.

Each of the piezoelectric elements 22 is composed of a piezoelectric ceramic such as PZT or barium titanate, or a piezoelectric single crystal such as PMN-PT, and both main surfaces 22a and 22b have an area of 0.5 mm ² and range from 80 μm to 120 μm. Are processed into a rectangular parallelepiped shape having a predetermined thickness (preferably 90 μm). The first and second dry film resists 23 and 24 are configured in the same form having different thicknesses. Such first and second dry film resists 23 and 24 are, for example, photocurable. And known functions in which a photosensitive resin composition is formed on the surface of a resin sheet-like support (for example, TMMF-S20 series (manufactured by Tokyo Ohka Kogyo Co., Ltd.) ). In this case, as the first and second dry film resists 23 and 24, those having a predetermined thickness in the range of 20 μm to 45 μm are selected. Then, a photomask (not shown) is arranged on each of the first and second dry film resists 23 and 24, and the first and second dry film resists 23 and 24 are respectively exposed to remove the photomask. By developing later, the first and second openings 23a, 24a are patterned and opened in an array. Each of the first and second openings 23a and 24a is formed to have a rectangular outline, but may be appropriately changed according to the outline of the main surfaces 22a and 22b of the piezoelectric element 22, for example.

  The silicon substrate 3 is formed with a through silicon via (TSV: Through Silicon Via) 31 penetrating in the vertical direction. On the upper surface side and lower surface side of the silicon substrate 3, wiring layers 32a and 32b and bump electrodes 33a and 33b are formed, respectively. Reference numerals 34a and 34b denote epoxy resins for insulating the bump electrodes 33a and 33b from each other. The silicon substrate 3 is placed on the transmission / reception unit 2 so that the bump electrode 33a on the lower surface side of the silicon substrate 3 is in contact with the second electrode film 25.

  On the silicon substrate 3, a communication circuit 40, a drive circuit 41, a power source 42, an amplifier circuit 43, an A / D conversion circuit 44, and a signal compression circuit 45 are mounted. Since the drive circuit 41 and the amplifier circuit 43 are respectively connected to the first and second electrode films 21 and 25 through the silicon through electrode 31, a transmission path until the reflected wave received by the transmission / reception unit 2 is amplified is provided. It will be as short as possible. The communication circuit 40 performs wireless communication with a communication unit 50 of the measuring instrument main body MB described later. The drive circuit 41 is an integrated circuit that selectively applies a pulse voltage to each piezoelectric element 22. The drive circuit 41 has switching means (not shown) for switching the piezoelectric element 22 to which the pulse voltage is applied. Since the power supply 42 needs to supply power only to the drive circuit 41 having a small control load and low power consumption, a thin and small-capacity battery is sufficient instead of a large-capacity power supply like a general power supply for home use. . The amplifier circuit 43 is an integrated circuit that amplifies the reflected wave (analog signal) received via the through silicon via 31, and the A / D conversion circuit 44 converts the reflected wave amplified by the amplifier circuit 43 into a digital signal. Integrated circuit. The digital signal converted by the A / D conversion circuit 44 is compressed by the signal compression circuit 45 and then wirelessly transmitted from the communication circuit 40 to the measuring device main body MB.

  The measuring instrument main body MB includes a communication unit 50, a signal expansion means 51, a control means (CPU) 52, a notification means 53, and a power supply 54. The communication unit 50 performs wireless communication with the communication circuit 40 of the ultrasonic probe AP. The signal expansion means 51 expands the compressed digital signal received from the ultrasonic probe AP, and outputs the expanded digital signal to the control means 52, and is constituted by an integrated circuit, for example. The control means 52 controls the driving circuit 41 of the ultrasonic probe AP and measures the blood vessel diameter by calculating the digital signal input from the signal expansion means 51. The notification unit 53 notifies the user of the measured blood vessel diameter, and includes a display unit such as a display for displaying the measured blood vessel diameter. As the power source 54, it is desirable to use a general household power source in consideration of the large control load of the control means 52 and the large power consumption.

  Here, it is conceivable to use communication standards such as Bluetooth (registered trademark) and wireless LAN, which are currently used for general purposes, for digital signal communication. In this case, since the raw data of the reflected wave of 20 MHz has a large amount of data, it is difficult to binarize (digitalize) and transmit this raw data at a sufficient sampling frequency, and there is a possibility that it cannot be transmitted. In view of this, the present embodiment includes a signal compression circuit 45 that compresses / decompresses a digital signal and a signal expansion unit 51. As the compression / decompression algorithm, it is desirable to use a known speech compression / decompression algorithm or a dedicated algorithm. The reason is that in an ordinary compression method, information necessary for analysis by the control means 52 is lost, and information once lost cannot be restored. However, as a matter of course, it is necessary to match the frequency band used by the piezoelectric element 22 and set the band capable of reversible compression to 1 decade or more.

  Next, a method for manufacturing the ultrasonic probe AP will be described with reference to FIGS. First, a plurality of piezoelectric elements 22 having the same thickness (that is, having the same oscillation frequency) are prepared. At the same time, a sheet having a heat-peelable or ultraviolet-curing release sheet 7 attached to the entire upper surface of the support 6 having rigidity such as silicon is prepared. When the support 6 is prepared, the acoustic matching layer 1 is formed on the upper surface of the release sheet 7 (see FIG. 3A). Here, as a method of forming the acoustic matching layer 1, a method of attaching using an adhesive or a solvent, a method of forming by a vapor deposition polymerization method, or the like can be used. When the acoustic matching layer 1 is formed of polyimide, parylene, or polyurea, it is preferably formed using a vapor deposition polymerization method. In the present embodiment, an opening 1 a for forming a wiring layer for performing wiring connection through the silicon through electrode 31 is formed in the acoustic matching layer 1.

  Next, the first electrode film 21 is formed on the upper surface of the acoustic matching layer 1 (see FIG. 3B). As the first electrode film 21, for example, a conductive metal material such as gold, copper, or chromium is used, and the first electrode film 21 is formed using a known sputtering apparatus, vacuum deposition apparatus, or the like. Next, a first dry film resist 23 having a thickness equivalent to that of the piezoelectric element 22 is pasted on the acoustic matching layer 1 and the first electrode film 21. In this case, in order to apply the first dry film resist 23 over the entire surfaces of the acoustic matching layer 1 and the first electrode film 21 with good adhesion, a roll type in which pressure is applied with a roll while heating, or a vacuum chamber under reduced pressure. A vacuum-type laminating apparatus that performs thermocompression bonding inside can be used. Next, a photomask (not shown) is arranged to expose the first dry film resist 23, and after removing the photomask, development is performed to open a plurality of first openings 23a surrounding the piezoelectric element 22 in an array ( (Refer FIG.3 (c)). In this case, the first opening 23 a is set to be slightly larger than the contour of the piezoelectric element 22. In the present embodiment, simultaneously with the opening of the first opening 23a, an opening 23b for forming a wiring layer for performing wiring connection with the flexible wiring board 4 is formed in the first dry film resist 23 immediately above the opening 1a. Yes. In addition, since a well-known thing can be utilized about exposure, image development, and removal of an exposed part or an unexposed part, detailed description is abbreviate | omitted here.

  And the piezoelectric element 22 is each arrange | positioned from the lower surface 22a side inside the 1st opening 23a so that it may be supported by the 1st electrode film 21 (refer FIG.3 (d)). When each piezoelectric element 22 is disposed, the second dry film resist 24 is pasted on the first dry film resist 23 including the upper surface 22b of the piezoelectric element 22 in the same manner as the first dry film resist 23, and exposure development is performed. Thus, the second opening 24a is formed, and the piezoelectric element 22 is sandwiched between the peripheral edge of the second opening 24a and the first electrode film 21 (see FIG. 3E). In the present embodiment, simultaneously with the opening of the second opening 24a, the opening 24b is formed in the second dry film resist 24 immediately above the opening 23b. Next, when the second opening 24a is opened, the second electrode film 25 is formed on the upper surface 22b of each piezoelectric element 22 so as to extend to the upper surface of the second dry film resist 24 (see FIG. 4A). ). Thereby, the transmission / reception unit 2 is formed. As the second electrode film 25, similarly to the first electrode film 21, for example, a conductive metal material such as gold, copper, or chromium is used, and is formed using a sputtering apparatus, a vacuum evaporation apparatus, or the like.

  Then, the silicon substrate 3 on which the silicon through electrode 31, the wiring layers 32 a and 32 b and the bump electrodes 33 a and 33 b are formed in advance is prepared, and the bump electrode 33 a on the lower surface side of the silicon substrate 3 is connected to the second electrode film 25. Thus, the silicon substrate 3 is installed on the transmission / reception unit 2. Prior to the installation of the silicon substrate 3, the spaces defined by the wiring layer forming openings 1a, 23b, and 24b are filled with, for example, silver paste 8 to strengthen the wiring (FIG. 4 (a)). Next, the drive circuit 41, the amplifier circuit 43, the A / D conversion circuit 44, and the signal compression circuit 45 are mounted on the silicon substrate 3 so as to be electrically connected to the bump electrode 33b (see FIG. 4B). ). At the same time, the communication circuit 40 and the power source 42 are mounted on the silicon substrate 3. Finally, although not particularly illustrated, the support 6 is heated and peeled off at the interface between the acoustic matching layer 1 and the peeling sheet 7, whereby the array type ultrasonic probe AP is manufactured.

  Next, a blood vessel diameter measurement and determination method using the blood vessel diameter measurement system MS will be described. With the ultrasonic probe AP attached to the user's wrist, the drive circuit 41 is driven by the control means 52 of the measuring instrument main body MB, and a pulse in the range of 40 to 100 V is applied to each piezoelectric element 22 via the silicon through electrode 31. When voltage is selectively applied, each piezoelectric element 22 oscillates an ultrasonic wave of about 20 MHz and is transmitted to the living body through the acoustic matching layer 1. When each piezoelectric element 22 receives the ultrasonic wave (reflected wave) reflected by the blood vessel B, the reflected wave (analog signal) is input to the amplifier circuit 43 via the through silicon via 31 and amplified. The amplified reflected wave (analog signal) is converted into a digital signal by the A / D conversion circuit 44. The digital signal converted by the A / D conversion circuit 44 is compressed by the signal compression circuit 45 and then wirelessly transmitted from the communication circuit 40 to the measuring device main body MB. The digital signal received by the communication unit 50 of the measuring device main body MB is developed by the signal development means 51 and then sent to the control means 52. The control means 52 calculates the blood vessel diameter by performing arithmetic processing on the digital signal. In addition, since the well-known thing can be utilized about the method of measuring the blood vessel diameter from a digital signal, the further detailed description is abbreviate | omitted. The blood vessel diameter measured by the control means 52 is notified to the user by the notification means 53. For example, the blood vessel diameter is displayed on a display unit such as a display.

  According to the above embodiment, since the transmission path until the reflected wave received by the transmission / reception unit 2 is amplified by the amplifier circuit 43 is shortened as much as possible, it is less susceptible to noise and the blood vessel diameter is accurately adjusted. And it can measure with good reproducibility. Further, on the ultrasonic probe AP side, since it is limited only to the function of oscillating ultrasonic waves and a function of amplifying the received reflected waves and converting them into digital signals, it consumes less power and generates heat. The amount is not so large. As a result, the ultrasonic probe AP is light in weight, has no inconvenience to the user during measurement, and has excellent wearability.

  In addition, according to the present embodiment, it is possible to make the plurality of piezoelectric elements 22 arranged in an array form less susceptible to noise when driving to switch signals at high speed, improving resolution by ultrasonic beam convergence, and reflecting waves (Reflected echo) Measurement point sensitivity at the time of reception is expected to be improved, and it is expected that measurement and imaging in a deep and wide range by driving a plurality of piezoelectric elements 22 arranged in an array form a phased array. A circuit that performs high-speed signal switching for the above-described purpose can be similarly mounted on the silicon substrate 3.

  Although the embodiments of the present invention have been described above, modifications can be made as appropriate without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the display unit such as a display that notifies the blood vessel diameter measured by the notification unit 53 with an image has been described as an example. Good.

  Further, the silicon substrate provided on the transmission / reception unit 2 is not limited to that shown in FIG. 1, and any silicon substrate on which the silicon through electrode 31 that connects the piezoelectric element 22 and the amplifier circuit 43 is formed may be used. Can do.

  In the above embodiment, the case where wireless communication is performed between the ultrasonic probe AP and the measuring device main body MB has been described as an example. However, the present invention can also be applied to a case where wired communication is performed between the ultrasonic probe AP and the measuring device main body MB.

  In the above embodiment, the digital signal compressed by the signal compression circuit 45 is transmitted to the measuring device main body MB and the digital signal expanded by the signal expansion means 51 is sent to the control means 52. When the accuracy required for the arithmetic processing by the above is high, the signal compression circuit 45 and the signal expansion circuit 51 may not be provided. In this case, the digital signal after A / D conversion is sent to the communication circuit 40, the digital signal is wirelessly transmitted from the communication circuit 40 to the measuring instrument body MB, and the digital signal received by the communication unit 50 is sent to the control means 52. Is output. According to this, the power consumption of the ultrasonic probe AP can be further reduced, the weight can be further reduced, and the wearability is further improved.

  AP ... Ultrasonic probe, MB ... Measuring instrument body, MS ... Blood vessel diameter measuring system, 2 ... Transmission / reception unit, 21 ... First electrode film (first electrode), 22 ... Piezoelectric element, 25 ... Second electrode film (second) Electrode), 3 ... silicon substrate, 31 ... silicon through electrode, 41 ... drive circuit, 42 ... power supply, 43 ... amplifier circuit, 44 ... A / D conversion circuit, 52 ... control means, 53 ... notification means.

Claims (1)

A blood vessel diameter measuring system for measuring a blood vessel diameter of a living body by a pulse echo method,
It has a plurality of piezoelectric elements arranged in an array on the same plane, applies a pulse voltage to each piezoelectric element, oscillates ultrasonic waves toward the blood vessels, and receives reflected waves that collide with the blood vessels and are reflected In an ultrasonic probe having a transmission / reception unit and a measuring instrument main body that measures the diameter of a blood vessel by analyzing a received reflected wave, the ultrasonic probe and the measuring instrument main body are connected in a communicable manner.
The ultrasonic probe further includes a silicon substrate on which a silicon through electrode penetrating in the vertical direction is formed with the mounting direction with respect to the living body facing down,
A drive circuit that selectively applies a pulse voltage to each piezoelectric element on a silicon substrate, a power source that supplies power to the drive circuit, an amplifier circuit that amplifies the received reflected wave, and the amplified reflected wave An A / D conversion circuit for converting to a digital signal is mounted, and is connected to the first electrode with which the lower surface of each piezoelectric element contacts and the second electrode with which the upper surface contacts with each other through a silicon through electrode,
A blood vessel diameter measuring system, characterized in that a control device for controlling a driving circuit and processing a digital signal to measure a blood vessel diameter and a notification means for notifying the measured blood vessel diameter are provided in the measuring device main body. .

Images