JP7084576B2 - Flow measuring device - Google Patents

Description

The present invention relates to a flow measuring device.

It is desired to measure the velocity of fluids, such as the flow rates of exhalation and inspiration in the human peripheral airways. On the other hand, the flow measuring devices described in Patent Document 1 and Patent Document 2 have been proposed. The flow measuring device can measure the flow of fluid by measuring the resistance value of the detection resistance element by using the same principle as the heat ray current meter.

International Publication No. 2011/045974 International Publication No. 2016/125842

In the above flow measuring device, the heater portion of the sensor circuit of the heat ray flow meter is formed in a thin and minute sensor circuit on a flexible circuit board film by applying photolithography. A heater is mounted on the peripheral surface and a hole is locally formed in a tubular spacer located at a portion corresponding to the inner peripheral surface of the cylindrical case of the heater element and the detection resistance element in the sensor circuit. A cavity is provided to thermally insulate the element and the resistance element for detection. As a result, the transmission of ambient thermal noise to the heater element and the detection resistance element and the influence thereof are suppressed, so that the measurement accuracy of the flow is ensured.

By the way, in the flow measuring device configured as described above, the sensor terminal portion is formed in a cylindrical case in order to take out the sensor terminal portion formed on a part of the carrier resin film on which the sensor circuit pattern is formed. It is taken out to the outside through a cut (slit) formed in the outer cylindrical body that passes through the hole and is wound in close contact with the outer periphery of the cylindrical case, and is connected to the measurement circuit. However, when there is a differential pressure inside and outside the cylindrical case, the fluid leaks through the above-mentioned cut and the fluid flowing in the cylindrical case is disturbed, which may reduce the measurement accuracy. ..

Further, a carrier resin film having a sensor circuit pattern formed on the inner peripheral surface of the cylindrical case is attached, and the resistor of the center circuit pattern comes into contact with the fluid to be measured flowing in the cylindrical case. The thickness of the resistor and the carrier resin film that supports it causes turbulence in the fluid to be measured, and the smaller the diameter, the lower the measurement accuracy.

The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a flow measuring device capable of measuring a fluid flow with high accuracy.

Based on the above circumstances, the present inventors have conducted various studies, and while providing a through hole penetrating in the radial direction in a part of the inner cylinder having a comparatively small diameter, the sensor circuit pattern is formed on the carrier resin film. The inner cylinder is formed with a carrier sheet on which the sensor circuit pattern is formed so that the heater element of the sensor circuit pattern is located in the through hole by forming and rolling the inner cylinder on a flat plate. It was found that when wrapped around the outer circumference of the cylinder, the heater element and the portion of the carrier resin film supporting the heater element are housed in the through hole, so that the flow of the fluid flowing through the inner cylinder is less likely to be disturbed. Further, when the terminal pad which is a part of the sensor circuit pattern formed on the carrier resin film is taken out to the outside, a through hole for forming a cavity is formed on the back surface of the heater element and is formed on the outside of the inner cylinder. A through hole for terminal extraction is further formed in the intermediate cylinder to be brought into close contact, and a terminal extraction formed in the intermediate cylinder via a region in which a part of the sensor circuit pattern is sandwiched between the inner cylinder and the intermediate cylinder. It was found that when the fluid is taken out through the through hole, the airtightness is enhanced and the leakage of the fluid from the inner cylinder is preferably suppressed. The present invention has been made based on these findings.

The gist of the first invention for achieving such an object is (a) a flow measuring device for measuring the velocity of a fluid, and (b) a through hole penetrating in the radial direction is locally formed. The carrier has an inner cylinder, (c) a carrier resin film wrapped around the outer peripheral surface of the inner cylinder, and (d) a microheater element so that the microheater element is located in the through hole. The carrier resin film is mounted on the inner cylinder with the carrier resin film sandwiched between the sensor circuit pattern formed on the surface of the resin film and (e) the outer peripheral surface of the inner cylinder. An intermediate cylinder having a through hole for a cavity and a through hole for taking out a terminal locally formed on the back surface of a portion of the sensor circuit pattern where the microheater element is located, and (f) a cavity formed in the intermediate cylinder. It includes an outer cylinder mounted on the outside of the intermediate cylinder so as to close the through hole, and is (g) derived from between the inner cylinder and the intermediate cylinder through the terminal take-out through hole. The sensor terminal portion of the carrier resin film is sandwiched between the inner cylinder and the inner peripheral surface of the intermediate cylinder.

The gist of the second invention is that, in the first invention, the sensor terminal portion of the carrier resin film is provided with a plurality of terminal pads of the sensor circuit pattern, and a plurality of terminals connected to the plurality of terminal pads. Is derived from the sensor terminal portion along the longitudinal direction of the outer cylindrical body.

The gist of the third invention is that, in the second invention, the plurality of terminal pads of the sensor circuit pattern are electrically connected to the end of the conducting wire via an anisotropic conductive film or a conductive paste. To be there.

The gist of the fourth invention is that in any one of the first to third inventions, the carrier resin film is composed of a paraxylene-based polymer having a thickness on the order of micron, and is the same as the carrier resin film. On the back surface of the carrier resin film at the portion where the microheater element, which is a part of the sensor circuit pattern formed on the surface, is located, the through hole for the cavity locally formed in the intermediate cylinder is formed. It is to be positioned.

The gist of the fifth invention is that in any one of the first to fourth inventions, the temperature compensating resistor for compensating for the temperature change of the heater element and the measured fluid provided in the sensor circuit pattern. To include a gas flow velocity measuring circuit consisting of a constant temperature drive circuit comprising a Wheatstone bridge circuit having the element as part of four resistors.

The gist of the sixth invention is that in any one of the first to fifth inventions, the flow measuring device measures the air flow of the living body, and the living body is based on the air flow of the living body. A gas flow calculation control unit that outputs a breathing signal that reflects the respiratory movement of the body, and a frequency component that synchronizes with the heartbeat of the living body superimposed on the breathing signal from the breathing signal output from the gas flow calculation control unit. It includes a waveform analysis control unit that extracts and outputs a heartbeat signal representing the beat.

The gist of the seventh invention is that in any one of the first to sixth inventions, the temperature of the fluid flowing through the inner cylinder is detected by using a temperature-sensitive film showing a color change. The purpose is to include a film detection unit.

According to the flow measuring device of the first invention, since the portion of the heater element and the carrier resin film supporting the heater element is housed in the through hole locally formed in the inner cylinder, the fluid flowing in the inner cylinder is accommodated. The flow is less likely to be disturbed. Further, the sensor terminal portion of the carrier resin film led out from between the inner cylinder and the intermediate cylinder through the through hole for taking out the terminal is formed between the inner cylinder and the inner peripheral surface of the intermediate cylinder. It is sandwiched between them to preferably prevent fluid leakage in the inner cylinder. These make it possible to measure the flow of fluid flowing in the inner cylinder with high accuracy.

According to the flow measuring device of the second invention, the sensor terminal portion of the carrier resin film is provided with a plurality of terminal pads of the sensor circuit pattern, and the plurality of lead wires connected to the plurality of terminal pads are described. It is derived from the sensor terminal portion along the longitudinal direction of the outer cylindrical body. As a result, the sensor terminal portion of the sensor circuit pattern is connected to the conducting wire along the longitudinal direction of the airflow sensor, so that the volume for connection is reduced.

According to the flow measuring device of the third invention, the plurality of terminal pads of the sensor circuit pattern are electrically connected to the end of the conducting wire via an anisotropic conductive film or a conductive paste. This makes it possible to significantly reduce the line width and line spacing of the terminal pad of the sensor circuit pattern, and the wire diameter and line spacing of the conducting wire connected to the line width and line spacing.

According to the flow measuring apparatus of the fourth invention, the carrier resin film is composed of a paraxylene-based polymer having a thickness of micron order, and is a part of the sensor circuit pattern formed on the surface of the carrier resin film. On the back surface of the carrier resin film at the portion where the microheater element is located, the through hole for the cavity locally formed in the intermediate cylinder is positioned. Therefore, the microheater element in which the through hole for the cavity formed in the intermediate cylinder is located on the back surface of the carrier resin film is supported by the carrier resin film having a thickness of micron order, and the microheater element. Since the heat capacity of the plastic is significantly reduced, an order of magnitude higher responsiveness can be obtained in the flow velocity measurement.

According to the flow measuring device of the fifth invention, a Wheatstone bridge circuit having a heater element provided in the sensor circuit pattern and a temperature compensating resistance element for compensating for a temperature change of the fluid to be measured as a part of four resistors. It is intended to include a gas flow velocity measuring circuit comprising a constant temperature drive circuit comprising. This enables accurate measurement regardless of the temperature change of the fluid to be measured.

According to the sixth invention, the waveform analysis control unit extracts a frequency component synchronized with the heartbeat of the living body superimposed on the breathing signal from the breathing signal output from the gas flow calculation control unit, and beats the breathing signal. A heartbeat signal representing motion is output. Therefore, by using the heartbeat signal, it is possible to easily detect the heartbeat signal representing the heartbeat of the living body without using the ECG electrode attached to the living body. That is, even an infant whose skin is weak and it is difficult to attach the ECG electrode to the skin for a long time for the purpose of electrocardiographic measurement can easily obtain a heartbeat signal. In addition, since it is possible to obtain a heartbeat signal that reflects the actual heart volume change, that is, the cardiac output, it is possible to confirm the presence or absence of heartbeat with high reliability as compared with the conventional method using an electrocardiographic induction waveform. In addition to being able to promptly perform medical treatment in the emergency life-saving field, it also has the effect of enabling clinical evaluation of cardiovascular drugs that not only change the heart rate but also change the cardiac output. ..

According to the flow measuring device of the seventh invention, since the temperature-sensitive film detecting unit that detects the temperature of the fluid flowing in the inner cylindrical body by using the temperature-sensitive film indicating the color change is included, the exhalation and inhalation of the living body are included. When used for measuring the flow of water, the breathing phenomenon can be confirmed by the color change of the temperature sensitive film, so if a problem occurs in the measurement of the flow measuring device, it is abnormal whether it is a piping system or a flow measuring device. There is an advantage that the judgment can be made easily.

It is a schematic diagram explaining the thorax of a living body. It is a schematic diagram which shows the lung and the heart housed in the thorax of FIG. It is a figure explaining the structure of the heart rate signal detection device of one Embodiment of this invention, and the main part of the control function of the electronic control device included in the structure. FIG. 3 is a perspective view showing an example in which the airflow sensor of FIG. 4 is provided on a mask covering the nose and mouth of a living body. It is a perspective view explaining the main part of the mechanical structure of the airflow sensor used in FIG. It is a figure explaining the cross section cut in the plane orthogonal to the longitudinal direction of the airflow sensor of FIG. 6 is a sectional view taken along line VII-VII of FIG. 6 cut along a plane passing through the center line of the airflow sensor of FIG. It is a figure explaining the carrier resin film used for the airflow sensor of FIG. 3, and the sensor circuit pattern formed on one surface thereof. It is a figure explaining the circuit structure of the gas flow velocity measurement circuit using the airflow sensor of FIG. FIG. 3 is a diagram illustrating a preliminarily obtained relationship between the output voltage of the gas flow velocity measuring circuit and the gas flow rate passing through the air flow sensor, which is a calibration curve used in the gas flow calculation control unit in the electronic control device of FIG. It is a figure which shows the breathing signal which shows the change of the airflow generated by the breathing detected from the living body by the airflow sensor of FIG. It is a figure which shows the frequency spectrum of the heartbeat signal obtained by the frequency analysis of the respiratory signal of FIG. It is a figure which shows the heartbeat signal synthesized by the inverse Fourier transform from the frequency component which constitutes the heartbeat signal included in the breathing signal of FIG. It is a flowchart which shows the main part of the control operation of the electronic control device of FIG. It is a process diagram explaining the process of forming a sensor circuit pattern on a carrier resin film in the manufacturing process of the airflow sensor of FIG. It is a figure explaining the mounting process of the inner cylinder in the manufacturing process of the air flow sensor of FIG. 3, (a) is the perspective view which shows the inner cylinder, (b) is orthogonal to the longitudinal direction of the inner cylinder. The cross-sectional view, (c) is a cross-sectional view taken along the line CC of (b). In the manufacturing process of the airflow sensor of FIG. 3, it is a figure explaining the winding process of winding a carrier resin film around an inner cylinder, and (a) is a perspective which shows the inner cylinder around which a carrier resin film is wound. FIG. 3 (b) is a sectional view orthogonal to the longitudinal direction of the inner cylinder around which the carrier resin film is wound, and FIG. 3 (c) is a sectional view taken along the line CC of (b). In the manufacturing process of the airflow sensor of FIG. 3, it is a figure explaining the intermediate cylinder winding process of winding an intermediate cylinder around the inner cylinder around which the carrier resin film is wound, and (a) is an inner cylinder. A perspective view illustrating an intermediate cylinder wound around the inner cylinder via a carrier resin film, (b) is a cross-sectional view orthogonal to the longitudinal direction of the intermediate cylinder wound around the inner cylinder via the carrier resin film. (C) is a sectional view taken along the line CC of (b). In the manufacturing process of the airflow sensor of FIG. 3, it is a figure explaining the outer cylinder winding process which winds an outer cylinder around an intermediate cylinder, and (a) is the outside attached to the outer periphery of the intermediate cylinder. A perspective view showing the cylinder, (b) is a cross-sectional view orthogonal to the longitudinal direction of the outer cylinder attached to the outer periphery of the intermediate cylinder by heat shrinkage, and (c) is a sectional view taken along the line CC of (b). Is. It is sectional drawing explaining the structure of the conventional airflow sensor, and is the figure corresponding to FIG. It is a perspective view which shows the airflow sensor of another Example of this invention, and is the figure which corresponds to FIG.

Hereinafter, the heart rate signal detection device according to an embodiment of the present invention will be described in detail with reference to the drawings.

(Example 1)
As shown in FIGS. 1 and 2, in the living body 10, a relatively rigid thoracic 18 surrounded by ribs 12, thoracic bones 14, and thoracic vertebrae 16 and a diaphragm 20 blocking the lower opening of the thoracic 18 were isolated. The lung 24 and the heart 26 are housed in the thoracic cavity, and the volume change of the heart 26 due to the beat is smaller than the volume change of the lung 24 due to the respiratory movement, but the exercise cycle is short, so that the ventilation waveform of the lung 24 Since it is clearly superimposed, we focused on the fact that if the respiratory waveform (ventilation waveform), which is the gas flow velocity or gas flow rate passing through the trachea 28 of the living body 10, is detected with high accuracy, the heartbeat signal is extracted from it. Hereinafter, it will be described in detail.

FIG. 3 is a diagram illustrating the configuration of the heartbeat signal detection device 30 according to the embodiment of the present invention and the functions of the electronic control device 40 provided in the heartbeat signal detection device 30. The heartbeat signal detection device 30 corresponds to the airflow sensor 36 attached to the intratracheal intubation tube 34 inserted into the trachea 28 of the living body 10 and the gas flow rate passing through the airflow sensor 36 based on the signal from the airflow sensor 36. A gas flow velocity measurement circuit 38 that outputs a measurement signal SM, an electronic control device 40 that extracts a heartbeat signal SH representing a volume change of the heart 26 from the measurement signal SM output from the gas flow velocity measurement circuit 38, and an electronic control device. It is provided with a display device 76 that displays the heart rate, the waveform of the heartbeat signal SH, the breathing waveform, the evaluation of the heartbeat waveform, etc., which are the signal processing results by 40.

Although the airflow sensor 36 is attached to the base of the tracheal intubation tube 34 in FIG. 3, it is sufficient as long as it detects the gas flow rate passing through the trachea 28 of the living body 10, so that it is in the middle of the tracheal intubation tube 34. It may be provided in a site or outlet, or in a flexible tube or connection adapter connecting the intratracheal intubation tube 34 and the ventilator 42. Further, a mask 44 covering the nose and mouth of the living body 10 shown in FIG. 4, a flexible tube connecting the mask 44 and the respirator 42, and an air flow sensor 36 are provided in a connection adapter. May be good. In FIGS. 3 and 4, the ventilator 42 is connected as needed and may not necessarily be provided.

The airflow sensor 36 functions as the flow measuring device of the present invention. FIG. 5 is a perspective view showing an example of the mechanical configuration of the airflow sensor 36, FIG. 6 is a cross-sectional view orthogonal to the longitudinal direction of the airflow sensor 36, and FIG. 7 is a view of VII-VII of FIG. It is a cross-sectional view. As shown in FIGS. 5, 6 and 7, the airflow sensor 36 is composed of a three-layered circular tube body that can be connected to the endotracheal intubation tube 34 and the ventilator 42. In FIG. 7, the flow direction AF of the airflow, which is the fluid to be measured, is indicated by an arrow.

Further, the airflow sensor 36 includes an inner cylinder 50, a carrier resin film 52, an intermediate cylinder 58, and an outer cylinder 60. The inner cylindrical body 50 is locally formed with a first through hole 48 penetrating in the radial direction and a second through hole (not shown). The carrier resin film 52 is wrapped around the outer peripheral surface of the inner cylindrical body 50. The inner peripheral surface of the carrier resin film 52 has one microheater element MH, two microwind direction elements MD1, MD2, and a temperature compensation resistance element TH, one microheater element MH, and two microwind direction elements. The sensor circuit pattern CC is formed so that the MD1 and MD2 are located in the first through hole 48 and the temperature compensation resistance element TH is located in the second through hole 49. The intermediate cylinder 58 is mounted on the inner cylinder 50 with the carrier resin film 52 sandwiched between the inner cylinder 50 and the outer peripheral surface, and is one of the carrier resin films 52, the microheater element MH of the sensor circuit pattern CC. And a pair of through holes 54 and 55 for cavities locally formed on the back surface of each of the part where the two micro wind direction elements MD1 and MD2 are located and the part where the temperature compensation resistance element TH is located, and for taking out the first terminal. It has a through hole 56. The outer cylinder 60 has a through hole 57 for taking out the second terminal, and is mounted on the outside of the intermediate cylinder 58 so as to close the pair of cavity through holes 54 and 55 formed in the intermediate cylinder 58. ..

Then, the sensor terminal portion 62 of the carrier resin film 52 led out from between the inner cylinder 50 and the intermediate cylinder 58 through the terminal take-out through hole 56 is formed on the outer peripheral surface of the inner cylinder 50 and the inside of the intermediate cylinder 58. It is sandwiched between the peripheral surface of the peripheral surface between the through hole 54 for the cavity and the through hole 56 for taking out the terminal. As a result, with the space between the inner cylinder 50 and the intermediate cylinder 58 sealed, it is led out from between the inner cylinder 50 and the intermediate cylinder 58 through the terminal take-out through hole 56. There is.

The sensor terminal portion 62 of the carrier resin film 52, which is led out from between the inner cylindrical body 50 and the intermediate cylindrical body 58 through the through hole 56 for terminal extraction, is a conducting wire composed of an enamel wire, a lead wire, a flexible wiring, a ribbon wiring, and the like. The ends of 64 are electrically connected via an anisotropic conductive film or a conductive paste. The conductor 64 is arranged along the longitudinal direction of the airflow sensor 36. The anisotropic conductive film is, for example, formed by mixing fine metal particles in which an insulating layer is coated on gold-plated nickel particles with a thermosetting resin into a film shape, and pressure is applied to the anisotropic conductive film. The part is selectively conductive.

The airflow sensor 36 has, for example, a length of about 50 mm and an outer diameter of about 11.2 mm. The inner cylinder 50 is composed of, for example, a fluororesin tube having an outer diameter of about 9.7 mm and a thickness of about 1 mm, and has higher rigidity than the middle cylinder 58 and the outer cylinder 60. The intermediate cylinder 58 and the outer cylinder 60 are composed of, for example, a heat-shrinkable tube made of Teflon (registered trademark) having a thickness of, for example, about 0.75 mm.

The carrier resin film 52 is composed of, for example, a resin film such as a polyimide resin or a paraxylylene-based resin, preferably a thin film resin film having a size of, for example, 0.6 μm to 15.0 μm in order to enhance thermal responsiveness. The sensor circuit pattern CC on the carrier resin film 52 is formed by photolithography from the thin film on the carrier resin film 52, for example, as shown in FIG. The sensor circuit pattern CC consists of eight terminals in which a microheater element MH, two micro wind direction elements MD1 and MD2, and a temperature compensation resistance element TH are arranged in parallel with the sensor terminal portion 62 of the carrier resin film 52, respectively. It is connected to each of our pair of terminals.

The microheater element MH, the two microwind direction elements MD1 and MD2, and the temperature compensation resistance element TH are formed of the same process and the same material so that the temperature coefficient TCR is similar to each other. The microheater element MH is used to detect the wind speed or the air volume, and the micro wind direction elements MD1 and MD2 are used to detect the flow rate of the forward flow and the backflow and to detect the wind direction.

The temperature compensation resistance element TH is for compensating for fluctuations in the sensor output due to the gas temperature. The resistance value of the temperature compensating resistance element TH is the resistance value of the microheater element MH in order to suppress the self-heating of the temperature compensating resistance element TH with the intention of detecting the air flow temperature with high accuracy by the temperature compensating resistance element TH. It is set about 10 times higher than that of. A plurality of terminal pads 65 of the sensor circuit pattern CC are provided at the tip of the sensor terminal portion 62, and the plurality of terminal pads 65 are connected to a bridge circuit 66 described later.

FIG. 9 shows a constant temperature type measuring circuit which is a part of the gas flow velocity measuring circuit 38 and measures the wind speed or the air volume by using the microheater element MH and the temperature compensation resistance element TH. The measurement circuit used to detect the wind direction using the pair of micro wind direction elements MD1 and MD2 is omitted. In FIG. 9, the gas flow velocity measuring circuit 38 is composed of four resistors R1 and R2, a resistor Rc composed of a temperature compensating resistor element TH, and a resistor Rh composed of a microheater element MH, and is a bridge power supply. The bridge circuit 66 to which the voltage Vs is applied and the output voltage Vout of the bridge circuit 66 are amplified by the feedback amplifier 68, and the current corresponding to the signal is applied to the bridge circuit 66 by the transistor 70 as the bridge power supply voltage Vs. The difference ΔV between the bridge power supply voltage Vs and the output voltage Vout corresponds to the air flow velocity.

In the gas flow velocity measuring circuit 38 configured as described above, when the gas flow velocity suddenly increases from the equilibrium state of the bridge circuit 66a, the temperature of the microheater element MH decreases and its resistance value decreases, so that the bridge circuit 66 The bridge power supply voltage Vs is increased by the feedback amplifier 68 so as to return to the initial equilibrium state, the temperature of the microheater element MH is raised, and the temperature of the microheater element MH is maintained at a constant temperature.

The gas flow rate FR (cc / min) or (L / min) is determined, for example, from the relationship between the preliminarily obtained calibration curve shown in FIG. 10, that is, the gas flow rate FR (L / min) and the square value of the voltage ΔV of the bridge circuit. The gas flow rate FR is calculated based on the voltage ΔV of the bridge circuit 66. By dividing the gas flow rate FR (L / min) by the flow cross-sectional area S (constant) in the airflow sensor 36, the gas flow rate FS (cm / sec) or (m / sec) can be obtained. In FIG. 10, black circles indicate the forward direction of the airflow (intake direction), and white circles indicate the measurement points measured in advance in the backward direction of the airflow (expiratory direction). The solid line is a curve showing King's theoretical model formula. Since this curve represents each measurement point, it is used as a calibration curve.

Returning to FIG. 3, the electronic control device 40 is composed of a so-called microcomputer in a form in which a CPU executes a program stored in ROM or RAM in advance, and the electronic control device 40 functions as a control function means. The control function means includes the following gas flow calculation control unit 70, waveform analysis control unit 72, and heart rate signal evaluation control unit 74, and includes a heart rate, a heart rate signal SH waveform, a breathing waveform, and a heartbeat waveform, which are signal processing results. The evaluation and the like are displayed on the screen of the display device 76.

The gas flow calculation control unit 70 is a gas flow velocity measurement circuit based on the relationship (calibration curve) between the gas flow rate FR (L / min) flowing in the air flow sensor 36 and the self-squared value of the voltage ΔV of the bridge circuit shown in FIG. The gas flow rate FR (L / min) is calculated based on the voltage ΔV (gas flow velocity signal) of the bridge circuit output from 38, and the change waveform of the gas flow rate FR, that is, the breathing representing the lung air volume reflecting the respiratory movement. Output the signal SR. The respiratory signal SR in FIG. 11 basically shows the periodic change of the gas flow rate FR synchronized with the respiration, that is, the respiratory waveform of the lung 24 of the living body, but a small pulsation synchronized with the heartbeat is superimposed. FIG. 12 shows a power spectrum showing the signal intensity for each frequency obtained by frequency analysis of the respiratory signal SR.

The waveform analysis control unit 72 extracts the heartbeat signal SH showing the heartbeat waveform from the breathing signal SR on which the heartbeat waveform is superimposed, based on the frequency characteristics of the heartbeat waveform having a fundamental frequency higher than the breathing waveform represented by the breathing signal SR. do. For example, the waveform analysis control unit 72 performs frequency analysis of the waveform represented by the heartbeat signal SH superimposed on the respiratory signal SR in synchronization with the beat of the heart 26 by Fourier transform, and the heartbeat is as shown in FIG. The fundamental frequency f0, the first harmonic f1, the second harmonic f2, and the third harmonic f3, which are the frequency components of the heartbeat signal SH appearing in the frequency spectrum of the signal SH, are obtained in advance, and as shown in FIG. 13, these frequency components are obtained. The heart rate signal SH is synthesized from the above using the inverse Fourier transform. The waveforms in FIGS. 12 and 13 are obtained from rats.

Further, the waveform analysis control unit 72 removes the frequency component synchronized with the beat of the heart 26 of the living body 10 superimposed on the respiratory signal SR from the respiratory signal SR output from the airflow sensor 36, that is, the heartbeat signal SH. It is removed, and the ventilation component signal SR0 representing the lung air volume component derived from the thoracic 18 and the diaphragm 20 of the living body 10 is output. The waveform analysis control unit 72 passes the respiratory signal SR through, for example, a low-pass filter or a bandpass filter that passes a frequency lower than the frequency component constituting the heartbeat signal SH, so that the lung air derived from the thoracic 18 and the diaphragm 20 of the living body 10 is passed. The ventilation component signal SR0 representing the quantity component is output. Alternatively, the waveform analysis control unit 72 extracts the frequency components constituting the respiration signal SR output from the airflow sensor 36 from the frequency spectrum, and the heartbeat signal SH is not superimposed on the frequency components by the inverse Fourier transform. The ventilation component signal SR0 representing the lung air volume component derived from the thorax 18 and the diaphragm 20 of 10 is output.

The heart rate signal evaluation control unit 74 calculates the heart rate HR of the living body 10 from the generation cycle of the heart rate signal SH, and determines, for example, an abnormality when the heart rate HR deviates from the upper limit value or the lower limit value of the preset reference range. Is performed, and the abnormality of the heart rate HR is output from the screen of the display device 76. Further, the heart rate signal evaluation control unit 74 calculates the amplitude value A0 of the heart rate signal SH, and makes an abnormality determination, for example, when the amplitude value A0 deviates from the upper limit value or the lower limit value of the preset reference range. The abnormality of the amplitude value A0 is output from the screen of the display device 76. Thereby, not only the medicinal effect of the cardiovascular drug having a chronotropic effect of changing the heart rate but also the medicinal effect of the cardiovascular drug having an inotropic effect of changing the cardiac output can be evaluated. In particular, it has the advantage of being able to evaluate the efficacy of cardiovascular drugs having an inotropic effect that changes cardiac output, which was not possible with ECG (electrocardiogram).

Further, the heartbeat signal evaluation control unit 74 evaluates the functional abnormality or the anatomical abnormality of the two chambers and two chambers constituting the heart 26 based on the heartbeat signal SH analyzed by the waveform analysis control unit 72, and determines the abnormal state. The indicated display is output from the screen of the display device 76. The heart rate signal evaluation control unit 74 calculates, for example, a correlation coefficient C between the heart rate waveform represented by the heart rate signal SH calculated by the waveform analysis control unit 72 and a plurality of types of abnormal evaluation patterns stored in advance, and the phase thereof. The dysfunction or anatomical abnormality of the two chambers and two chambers constituting the heart 26, which is indicated by the abnormality evaluation pattern in which the relational number C exceeds a preset determination value, is determined, and the degree of the abnormality is evaluated. Since the heartbeat waveform indicated by the heartbeat signal SH represents the sum of the capacity changes of the two chambers and two chambers constituting the heart 26, the dysfunction or dissection of either of the two chambers and the two chambers having different volume change timings. This is because it reflects anatomical abnormal information. In addition, under artificial respiration management, positive end-expiratory pressure (PEEP), which attempts to prevent alveolar collapse and improve pulmonary oxygenation by applying pressure above atmospheric pressure, especially at the end of exhalation. If is adopted, the pressure of the alveoli may limit the expansion of the volume of the heart 26 in contact with it and affect the hemodynamics, but the abnormal evaluation pattern and heartbeat that reflect such a condition. An abnormality evaluation is performed in which the expansion of the volume of the heart 26 is limited based on the correlation coefficient with the heartbeat waveform represented by the signal SH.

FIG. 14 is a flowchart illustrating a main part of the control operation of the electronic control device 40, that is, a heartbeat signal detection / evaluation routine. In step S1 (hereinafter, the step is omitted) corresponding to the gas flow calculation control unit, the voltage ΔV of the bridge circuit of the gas flow velocity measuring circuit 38 is read in a period of at least one respiratory cycle or more of the living body 10.

Next, in S2 corresponding to the gas flow calculation control unit 70, for example, the gas flow rate FR (L / min) flowing in the air flow sensor 36 and the voltage ΔV of the bridge circuit of the gas flow rate measurement circuit 38 shown in FIG. From the pre-stored relationship with the square value ΔV ² , the gas flow rate FR is based on the square value ΔV ² of the voltage ΔV of the bridge circuit of the gas flow velocity measuring circuit 38 that reflects the actual gas flow velocity passing through the airflow sensor 36. At the same time, the breathing signal SR representing the change waveform of the gas flow rate FR, that is, the breathing waveform is calculated.

Next, in S3 corresponding to the waveform analysis control unit 72, the heartbeat signal SH showing the heartbeat waveform from the breathing signal SR on which the heartbeat waveform is superimposed is based on the frequency characteristics of the heartbeat waveform having a fundamental frequency higher than that of the breathing signal SR. Is extracted. For example, a frequency analysis of the waveform represented by the heartbeat signal SH superimposed on the breathing signal SR in synchronization with the beat of the heart 26 is performed by Fourier transform and appears in the frequency spectrum of the heartbeat signal SH as shown in FIG. The basic frequencies f0, the first harmonic f1, the second harmonic f2, and the third harmonic f3, which are the frequency components of the heartbeat signal SH, are obtained in advance, and as shown in FIG. 13, the inverse Fourier transform is used from these frequency components. The heartbeat signal SH is synthesized. The heartbeat signal SH superimposed on the respiratory signal SR is collected, for example, by using an ECG waveform as a trigger.

Further, from the breathing signal SR output from the airflow sensor 36, the frequency component synchronized with the beat of the heart 26 of the living body 10 superimposed on the breathing signal SR is removed, that is, the heartbeat signal SH is removed, and the lungs of the living body 10 are removed. A ventilation component signal SR0 is calculated, which represents only the change in the gas flow rate FR corresponding to the volume change due to 24, and represents the lung air volume component derived from the thoracic 18 and the diaphragm 20 of the living body 10 in which the heartbeat signal SH is not superimposed. ..

Then, the heartbeat signal SH is removed from the breathing signal SR by passing the breathing signal SR through, for example, a low-pass filter or a bandpass filter that passes a frequency lower than the frequency component constituting the heartbeat signal SH, and the heartbeat signal SH is superimposed. The ventilation component signal SR0 representing the lung air volume component derived from the thoracic 18 and the diaphragm 20 of the living body 10 is calculated. Alternatively, the frequency components constituting the frequency spectrum of the respiratory signal SR output from the airflow sensor 36 are extracted, and the frequency components are derived from the thorax 18 and the diaphragm 20 of the living body 10 to which the heartbeat signal SH is not superimposed by the inverse Fourier transform. The ventilation component signal SR0 representing the lung air volume component of is calculated.

Next, in S4 corresponding to the heart rate signal evaluation control unit 74, the heart rate HR of the living body 10 is calculated from the generation cycle of the heart rate signal SH, and for example, the heart rate HR is the upper limit value or the lower limit value of the preset reference range. Abnormality judgment is performed when it deviates from. Further, the amplitude value A of the heart rate signal SH is calculated, and for example, when the amplitude value A deviates from the upper limit value or the lower limit value of the preset reference range, the abnormality determination of the cardiac output is performed. Further, based on the heartbeat signal SH analyzed by the waveform analysis control unit 72, the functional abnormality or the anatomical abnormality of the two chambers and two chambers constituting the heart 26 is evaluated. For example, a correlation coefficient C between the heartbeat waveform represented by the heartbeat signal SH and a plurality of types of abnormality evaluation patterns stored in advance is calculated, and the abnormality evaluation pattern in which the correlation coefficient C exceeds a preset determination value indicates. , The dysfunction or anatomical abnormality of the two chambers and two chambers constituting the heart 26 is determined, and the degree of the abnormality is evaluated.

Then, in S5, an abnormality in the heart rate HR, an abnormality in the amplitude value A0 (cardiac output), a functional abnormality in two chambers and two chambers constituting the heart 26, or an anatomical abnormality are output from the screen of the display device 76. Will be done. Thereby, not only the medicinal effect of the cardiovascular drug having a chronotropic effect of changing the heart rate but also the medicinal effect of the cardiovascular drug having an inotropic effect of changing the cardiac output can be evaluated. In particular, it has the advantage of being able to evaluate the efficacy of cardiovascular drugs having an inotropic effect that changes cardiac output, which was not possible with ECG (electrocardiogram). In addition, under artificial respiration management, positive end-expiratory pressure (PEEP), which attempts to prevent alveolar collapse and improve pulmonary oxygenation by applying pressure above atmospheric pressure, especially at the end of exhalation. If is adopted, the pressure of the alveoli may limit the expansion of the volume of the heart 26 in contact with it and affect the hemodynamics, but the abnormal evaluation pattern and heartbeat that reflect such a condition. An abnormality evaluation is performed in which the expansion of the volume of the heart 26 is limited based on the correlation coefficient with the heartbeat waveform represented by the signal SH.

FIG. 15 shows a step of forming the sensor circuit pattern CC on the carrier resin film 52 in the manufacturing process of the airflow sensor 36. In FIG. 15, in the resist coating step P1, the photoresist is applied by spin coating on the carrier resin film 52 made of a polyimide resin having a thickness of about 12.5 μm. Next, in the exposure / development step P2, after exposure is performed through a mask having the same pattern as the sensor circuit pattern CC, an unexposed portion having the same pattern as the sensor circuit pattern CC and the same pattern is removed in advance by cleaning. Next, in the sputtering step P3, a thin film of gold is fixed to one surface including a portion from which a metal such as copper, aluminum, gold, platinum, and chromium, preferably gold, has been sputtered to remove the resist. Then, in the resist removing step P4, the resist is removed, so that a sensor circuit pattern CC made of a thin film of gold is formed on the portion of the carrier resin film 52 from which the resist has been removed in advance.

16 to 19 are views for explaining the manufacturing process of the airflow sensor 36. FIG. 16 shows a step of facilitating the inner cylindrical body 50 in which the first through hole 48 and the second through hole 49 are formed. 16 (a) is a perspective view showing the inner cylinder 50, FIG. 16 (b) is a cross-sectional view orthogonal to the longitudinal direction of the inner cylinder 50, and FIG. 16 (c) is the center of the inner cylinder 50. It is a cross-sectional view of the surface passing through the line and the first through hole 48, that is, the cross-sectional view taken along the line CC of FIG. 16 (b).

FIG. 17 shows the microheater element MH of the sensor circuit pattern CC, the two micro wind direction elements MD1 and MD2, and the temperature compensation resistance in the frame of the first through hole 48 and the second through hole 49 formed in the inner cylindrical body 50. A carrier resin film 52 that has been previously curved by plastic deformation so as to accommodate the element TH is placed on the inside of the surface on which the sensor circuit pattern CC is formed, and is about half the circumference of the outer peripheral surface of the inner cylinder 50. The winding process of wrapping and adhering to each other with, for example, silicon oil is shown. The sensor circuit pattern CC may be formed on the outer side (outer circumference) of the carrier resin film 52. Even in this way, although there is a slight decrease in sensitivity, a prima facie function can be obtained.

FIG. 17 (a) is a perspective view showing an inner cylinder 50 around which the carrier resin film 52 is wound, and FIG. 17 (b) is orthogonal to the longitudinal direction of the inner cylinder 50 around which the carrier resin film 52 is wound. 17 (c) is a cross-sectional view of a surface passing through the center line of the inner cylinder 50 around which the carrier resin film 52 is wound and the first through hole 48, that is, C of FIG. 17 (b). -C sectional view.

FIG. 18 shows a microheater element MH of a sensor circuit pattern CC formed on the inner surface of a carrier resin film 52 wound around an inner cylinder 50, two micro wind direction elements MD1 and MD2, and a temperature compensation resistance element TH. The intermediate cylinder winding step in which the intermediate cylinder 58 is wound around the inner cylinder 50 by heat shrinkage so as to be within the frame of the through holes 54 and 55 formed in the intermediate cylinder 58 is shown. As a result, the carrier resin film 52 is sandwiched between the intermediate cylindrical body 58 and the inner cylindrical body 50. At this time, the sensor terminal portion 62 of the carrier resin film 52 led out from between the inner cylinder 50 and the intermediate cylinder 58 through the terminal take-out through hole 56 is the outer peripheral surface of the inner cylinder 50 and the intermediate cylinder 58. The inner peripheral surface is sandwiched and sealed between the partial peripheral surface between the through hole 54 for the cavity and the through hole 56 for taking out the terminal.

FIG. 18A is a perspective view showing an intermediate cylinder body 58 attached to the outer periphery of the inner cylinder body 50 by heat shrinkage via a carrier resin film 52, and FIG. 18B is a perspective view showing the outer circumference of the inner cylinder body 50. It is a cross-sectional view orthogonal to the longitudinal direction of the intermediate cylinder 58 attached by heat shrinkage through the carrier resin film 52, and FIG. 18 (c) shows the outer periphery of the inner cylinder 50 via the carrier resin film 52. FIG. 3 is a sectional view of a surface passing through a center line of an intermediate cylinder 58 attached by heat shrinkage and a first through hole 48 and a through hole 54 for a cavity, that is, a sectional view taken along the line CC of FIG. 18 (b).

FIG. 19 shows the outer periphery of the intermediate cylinder 58 attached to the outer periphery of the inner cylinder 50 by heat shrinkage via the carrier resin film 52, from the first terminal outlet hole 56 to the second terminal outlet hole of the intermediate cylinder 58. The outer cylinder winding step in which the outer cylinder 60 is wound by heat shrinkage so that 57 is displaced by a predetermined distance in the circumferential direction is shown. As a result, the through holes 54 and 55 for the cavity of the intermediate cylinder 58 are closed by the outer cylinder 60, and a closed cavity (cavity) for thermal insulation is formed in the through holes 54 and 55 for the cavity. Then, after the conducting wire 64 is electrically connected to the sensor terminal portion 62 led out from the through hole 57 for taking out the second terminal of the outer cylindrical body 60 by an anisotropic conductive film, a conductive paste, or a conductive adhesive, The whole is coated with parylene C using a parylene deposition apparatus.

19 (a) is a perspective view showing an outer cylinder 60 attached to the outer periphery of an intermediate cylinder 58 attached to the outer periphery of the inner cylinder 50 by heat shrinkage, and FIG. 19 (b) is an inner view. FIG. 19 (c) is a cross-sectional view orthogonal to the longitudinal direction of the outer cylindrical body 60 attached to the outer periphery of the intermediate cylindrical body 58 attached to the outer periphery of the cylindrical body 50 by heat shrinkage, and FIG. 19 (c) shows the inner cylindrical body 50. A cross-sectional view of a surface passing through the center line of the outer cylindrical body 60 attached to the outer periphery of the intermediate cylindrical body 58 attached to the outer periphery and the first through hole 48 and the through hole 54 for a cavity, that is, FIG. (B) is a sectional view taken along the line CC.

FIG. 20 is a cross-sectional view illustrating a conventional two-layer structure airflow sensor 136. In the air flow sensor 136, the heater element 138 and the like in the sensor circuit 142 are formed on the flexible circuit board film 140 by applying photolithography to a small thickness, and the sensor circuit 142 is formed on the inner circumference of the cylindrical case 144. A through hole for forming a cavity is formed in a local portion corresponding to the inner peripheral surface of the cylindrical case 144 such as the heater element 138 in the sensor circuit 142 mounted on the surface, and the heater element 138 or the like is thermally formed. There is a cavity (caboti) that insulates the inside. As a result, the transmission of ambient thermal noise to the heater element 138 and the like and the influence thereof are suppressed, so that the measurement accuracy of the flow is ensured.

In the airflow sensor 136 configured in this way, for example, as shown in FIG. 20, a cylinder is used to take out the sensor terminal portion 148 formed in a part of the carrier resin film 140 on which the sensor circuit 142 is formed. A through hole for forming a cavity formed in the body case 144 is taken out to the outside through a cut (slit) 150 formed in the outer cylindrical body wound around the outer periphery of the cylindrical case 144 in a close contact state, and is taken out and fixed in position. It is connected to the measurement circuit of. However, if there is a differential pressure inside and outside the cylindrical case 144, the fluid may leak through the above-mentioned cut 150 and the fluid flowing in the cylindrical case 144 may be disturbed, resulting in a decrease in measurement accuracy. was there. Further, the carrier resin film 140 on which the sensor circuit 142 is formed is attached to the inner peripheral surface of the cylindrical case 144, and the heater element (resistor) 138 or the like of the center circuit 142 flows through the cylindrical case 144. Although it comes into contact with the fluid, the thickness of the heater element (resistor) 138 and the carrier resin film 140 that supports it causes turbulence in the fluid to be measured, which is one of the reasons why the smaller the diameter, the lower the measurement accuracy. It was.

As described above, according to the airflow sensor 36 of this embodiment, the microheater element MH, the two microwind direction elements MD1 and MD2, and the temperature compensation resistance element TH are the first penetrations locally formed in the inner cylinder 50. Since it is housed in the hole 48 and the second through hole 49, the flow of the fluid flowing in the inner cylindrical body 50 is less likely to be disturbed. Further, the sensor terminal portion 62 of the carrier resin film 52 led out from between the inner cylinder 50 and the intermediate cylinder 58 through the through hole 56 for taking out the first terminal and the through hole 57 for taking out the second terminal is through the cavity. A fluid leak in the inner cylinder 50 is sandwiched between the inner cylinder 50 and the outer peripheral surface of the intermediate cylinder 58 at the circumferential portion between the hole 54 and the through hole 56 for taking out the first terminal. Is preferably prevented. As a result, the flow of the fluid flowing in the inner cylindrical body 50 can be measured with high accuracy.

Further, according to the airflow sensor 36 of the present embodiment, the sensor terminal portion 62 of the carrier resin film 52 is provided with a terminal pad 65 having a sensor circuit pattern CC, and a plurality of lead wires 64 connected to the terminal pad 65 are provided. It is derived from the sensor terminal portion 62 along the longitudinal direction of the airflow sensor 36. As a result, the conducting wire 64 along the longitudinal direction of the airflow sensor 36 is connected from the sensor terminal portion 62 of the sensor circuit pattern CC, so that the volume for connection is reduced.

Further, according to the airflow sensor 36 of this embodiment, the terminal pad 65 of the carrier resin film 52 is electrically connected to the end of the conducting wire 64 via an anisotropic conductive film or a conductive paste. This makes it possible to significantly reduce the line width and line spacing of the terminal pad 65 of the sensor circuit pattern CC, and the wire diameter and line spacing of the conducting wire 64 connected to the line width and line spacing.

Further, according to the airflow sensor 36 of the present embodiment, the carrier resin film 52 is made of a paraxylene-based polymer having a thickness on the order of micron, and is one of the sensor circuit patterns CC formed on the surface of the carrier resin film 52. The microheater element MH, the two microwind direction elements MD1 and MD2, and the temperature compensation resistance element TH are located in the hollow through holes 54 and 55 locally formed in the intermediate cylinder 58, respectively. ing. Therefore, the microheater element MH, the two microwind direction elements MD1, MD2, and the temperature compensation resistance element TH, which are located in the through holes 54 and 55 for the cavity formed in the intermediate cylinder 58, have a thickness on the order of micron. Since it is supported by the carrier resin film 52 and the heat capacity of the microheater element is significantly reduced, an order of magnitude higher responsiveness can be obtained in flow velocity measurement.

Further, according to the airflow sensor 36 of the present embodiment, the microheater element MH provided in the sensor circuit pattern CC and the temperature compensation resistance element TH for compensating for the temperature change of the fluid to be measured are a part of four resistors. The present invention includes a gas flow velocity measuring circuit 38 including a constant temperature driving circuit including a Wheatstone bridge circuit 66. This enables accurate measurement regardless of the temperature change of the fluid to be measured.

Further, according to the electronic control device 40 of the present embodiment, the waveform analysis control unit 72 synchronizes the breathing signal output from the gas flow calculation control unit 70 with the pulsation of the heart of the living body superimposed on the breathing signal. The frequency component is extracted, and a heartbeat signal representing the pulsation is output. Therefore, by using the heartbeat signal, it is possible to easily detect the heartbeat signal representing the heartbeat of the living body without using the ECG electrode attached to the living body. That is, even an infant whose skin is weak and it is difficult to attach the ECG electrode to the skin for a long time for the purpose of electrocardiographic measurement can easily obtain a heartbeat signal. In addition, since it is possible to obtain a heartbeat signal that reflects the actual heart volume change, that is, the cardiac output, it is possible to confirm the presence or absence of heartbeat with high reliability as compared with the conventional method using an electrocardiographic induction waveform. In addition to being able to promptly perform medical treatment in the emergency life-saving field, it also has the effect of enabling clinical evaluation of cardiovascular drugs that not only change the heart rate but also change the cardiac output. ..

(Example 2)
Next, the airflow sensor 90 of another embodiment of the present invention will be described. In the following description, the parts common to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 21 is a perspective view showing the airflow sensor 90. Adjacent to the above-mentioned airflow sensor 36, the airflow sensor 90 is provided with a temperature-sensitive film detection unit 92 that detects the temperature of the fluid flowing through the inner cylindrical body 50 by using the temperature-sensitive film 98 that exhibits a color change. It is composed of. The temperature-sensitive film detection unit 92 corresponds to the annular groove 94 in which the inner cylinder 50 is exposed by removing the intermediate cylinder 58 and the outer cylinder 60 in a band shape in the circumferential direction, and the groove bottom of the annular groove 94. A plurality of through holes 96 formed in the inner cylindrical body 50 located at the site to be formed, a band-shaped temperature-sensitive film 98 wound so as to close the opening of the annular groove 94, and both ends in the width direction of the temperature-sensitive film 98. A pair of temperature-sensitive film fixing bands 100 wound around both side portions of the annular groove 94 of the outer cylindrical body 60 for fixing the portions are provided. A space is formed between the temperature-sensitive film 98 and the inner cylinder 50 to communicate with the inside of the inner cylinder 50 through the through hole 96.

The temperature-sensitive film 98 is formed by applying a liquid temperature-indicating ink on a thin film resin film having a thickness of about several μm to 10 μm, and the heat capacity is reduced. For example, when the thin film resin film is 5 μm and the coating thickness of the temperature indicating ink is 6.8 μm, the response time is 373 ms, so that it has been confirmed that the response characteristics are sufficient for the human respiratory cycle of 3.3 s. ..

As the temperature indicating ink, an ink whose color changes between the exhaled temperature of the living body and the inspiratory temperature (room temperature) is selected. For example, a temperature indicating ink whose color disappears at 33 ° C. is used. As a result, the color of the temperature-sensitive film 98 changes periodically according to the respiration of the living body, so that the respiration state can be easily detected without energy.

Although the embodiments of the present invention have been described above, the present invention is also applied to other aspects.

For example, the airflow sensor 36 of the above-described embodiment is used by being connected to an intratracheal intubation tube 34, a flexible tube of a mask 44, or the like. It may be used by inserting it inside.

The airflow sensor 36 of the above-described embodiment measures the airflow of the exhaled air and the inspiratory air of the living body, but the fluid to be measured may be a liquid. For example, it may be connected to an infusion conduit of an infusion device to measure the flow velocity of the infusion, or it may be inserted into a living body to detect the flow velocity in the urinary tract, the flow velocity in a blood vessel, and the flow velocity of the infusion. May be used to do so.

Further, the airflow sensor 36 of the above-described embodiment is for medical use for measuring the airflow of exhaled breath and inhalation of a living body for medical purposes, but it does not necessarily have to be for medical use and is used for applications different from the medical field. You may.

It should be noted that the above description is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the spirit of the present invention.

10: Living body 12: Rib 14: Sternum 16: Thoracic vertebra 18: Thoracic spine 20: Diaphragm 24: Lung 26: Heart 28: Trachea 30: Heart rate signal detection device 34: Tracheal insertion tube 36: Airflow sensor (flow measurement device)
38: Gas flow velocity measuring circuit 40: Electronic control device 42: Ventilator 44: Mask 48: First through hole 49: Second through hole 50: Inner cylinder 52: Carrier resin film 54: Cavity through hole 55: Cavity Through hole 56: Through hole for taking out the first terminal (through hole for taking out the terminal)
57: Through hole for taking out the second terminal (through hole for taking out the terminal)
58: Intermediate cylinder 60: Outer cylinder 62: Sensor terminal 64: Lead wire 65: Terminal pad 66: Bridge circuit 68: Feedback amplifier 70: Gas flow calculation control unit 72: Waveform analysis control unit 74: Heart rate signal law control unit 76: Display 90: Airflow sensor (flow measuring device)
92: Temperature sensitive film detection unit 94: Circular groove 96: Through hole 98: Temperature sensitive film MH: Micro heater element MD1, MD2: Micro wind direction element TH: Temperature compensation resistance element CC: Sensor circuit pattern

Claims (7)

A flow measuring device that measures the velocity of a fluid.
An inner cylinder with locally formed through holes that penetrate in the radial direction,
A carrier resin film wrapped around the outer peripheral surface of the inner cylinder, and
A sensor circuit pattern having a microheater element and formed on the surface of the carrier resin film so that the microheater element is located in the through hole .
It is attached to the inner cylinder with the carrier resin film sandwiched between the outer peripheral surface of the inner cylinder, and is locally applied to the back surface of the carrier resin film where the microheater element is located in the sensor circuit pattern. An intermediate cylinder having a hollow through hole and a terminal take-out through hole formed
Includes an outer cylinder mounted on the outside of the intermediate cylinder so as to close the cavity through hole formed in the intermediate cylinder.
The sensor terminal portion of the carrier resin film, which is derived from between the inner cylinder and the intermediate cylinder through the through hole for taking out the terminal, is formed between the inner cylinder and the inner peripheral surface of the intermediate cylinder. A flow measuring device characterized by being pinched. The sensor terminal portion of the carrier resin film is provided with a plurality of terminal pads of the sensor circuit pattern, and a plurality of conductors connected to the plurality of terminal pads are directed from the sensor terminal portion in the longitudinal direction of the outer cylinder. The flow measuring device according to claim 1, wherein the flow measuring device is derived according to the above. The flow measurement according to claim 2, wherein the plurality of terminal pads of the sensor circuit pattern are electrically connected to the ends of the plurality of conductors via an anisotropic conductive film or a conductive paste. Device. The carrier resin film is composed of a para-xylene-based polymer having a thickness on the order of microns.
The said is locally formed on the intermediate cylinder on the back surface of the carrier resin film at the portion where the microheater element, which is a part of the sensor circuit pattern formed on the surface of the carrier resin film, is located. The flow measuring device according to any one of claims 1 to 3, wherein a through hole for a cavity is positioned. Gas flow velocity measurement consisting of a constant temperature drive circuit including a Wheatstone bridge circuit having a heater element provided in the sensor circuit pattern and a temperature compensation resistance element for compensating for a temperature change of the fluid to be measured as a part of four resistors. The flow measuring device according to any one of claims 1 to 4, wherein the circuit is included. The flow measuring device measures the airflow of a living body, and is transmitted from a gas flow calculation control unit that outputs a breathing signal that reflects the respiratory movement of the living body based on the airflow of the living body, and a gas flow calculation control unit. It is characterized by including a waveform analysis control unit that extracts a frequency component synchronized with the heartbeat of the living body superimposed on the breathing signal from the output breathing signal and outputs a heartbeat signal representing the heartbeat. The flow measuring device according to any one of claims 1 to 5. The flow measuring device according to any one of claims 1 to 6, further comprising a temperature sensitive film detecting unit that detects the temperature of the fluid flowing through the inner cylindrical body by using a temperature sensitive film indicating a color change. ..

Images