JP2819252B2 - Bidirectional fetal signaling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention obtains a fetal signal from the abdominal wall of a pregnant woman and, if necessary, extracts information on the physiological condition of the fetus from the signal, and at the same time, produces an acoustically effective sound for the fetus as required. More particularly, the present invention relates to a device suitable for autonomous use of a pregnant woman and having a structure and a function suitable for being worn on an abdominal wall.

[0002]

2. Description of the Related Art Fetal monitoring and its technology are already widely used. Recently, a device having a configuration suitable for self-care of a pregnant woman at home has been proposed and used. Also, regarding in-hospital use and self-management use of pregnant women,
In order to avoid confinement of the mother as much as possible, it is widely used to wirelessly transmit necessary signals or information from a fetal signal collecting device on the maternal abdominal wall. By such unrestrained monitoring, fetal monitoring can be performed in the mother's daily living conditions for the first time, and fetal asphyxia or a stage before it, and sudden changes in the physiological state of the fetus due to a sudden accident can be effectively found.

On the other hand, in a fetal diagnosis using a fetal monitoring device, a so-called non-stress test (non-st
An inspection technique called “less test, NST” is effectively used. In this case, the mother simply takes a sitting position or a recumbent position, and a fetal heart rate diagram is acquired for a certain period of time (for example, about 20 to 60 minutes). The doctor knows the baseline level, the state of heart rate fluctuation, and the like from the fetal heart rate chart, and knows the physiological state of the fetus. That is, the baseline level is appropriate according to the age of the fetus, and minute variations in heart rate (variability) and transient acceleration (accel)
is observed according to a certain pattern, that is, when there is a reactive pat (reactive pat).
In tern), the physiological condition of the fetus is presumed to be good. In the medical setting, these procedures are already quite routine.

[0004] However, when the heart rate variability and the transient acceleration are not seen at an appropriate level, this is interpreted as a resting phase of a well-formed fetus, or a poor state of fetal asphyxia or A state that has lost reactivity due to a situation close to it (nonreac
In some cases, the judgment as to whether to interpret the information as “active pattern” is obvious. In such a case, a so-called arousal test or acoustic stimulation test (Acoustic)
A test called "stimulation test (AST)" is additionally performed as a part of the non-stress test. In this case, an audible sound having a sound pressure sufficient to awaken a sleeping fetus is sent from the abdominal wall of the mother, and the fetal heart rate fluctuation is observed. In response to such an acoustic stimulus, the fluctuation pattern of the fetal heart rate changes to the resting phase (restin phase).
g phase) to active phase (activephase)
In the case of e), the condition of the fetus is presumed to be good.

[0005] The acoustic stimulator for this arousal test is also substantially established as an apparatus technology. As a typical example, a hand-held battery-operated acoustic signal generator is an acoustic radiating surface to be pressed against the maternal abdominal wall. , In which a simple buzzer or beeper is mounted, which is made to sound by a push button switch. As an example, frequency 7
An object that emits a sound of 5 Hz and a sound pressure of 74 dB under water directly below a radiation surface for 3 seconds is known. However, such a stimulus sound is not a pleasant thing to be heard by an adult, but rather an unpleasant impression. Although it may be suitable for the purpose of the stimulus test,
Perhaps this is not difficult to expect to be uncomfortable for the fetus.

On the other hand, among the various facts found in the field test of a fetal monitoring device left to the self-management of a pregnant woman, the pregnant woman can use her own fetal heartbeat signal, specifically, a fetal heart sound or ultrasonic Doppler fetal heartbeat. This includes a noticeable tendency to listen to signals and make them safe. However, the emotional phenomenon that a pregnant woman feels reassured by hearing the signal of her fetus has been known to practitioners for a long time. Attempts to provide pregnant women with personal stethoscopes or fetal Doppler heart rate detectors for such effects have been successfully made. Also, in the case of a fetal signal collection telemeter transmitter for fetal monitoring, there is also an example in which an earphone for the pregnant woman himself can be connected so that the pregnant woman wearing it can simultaneously listen to the fetal signal being collected is there.

Conversely, the fetal acoustic environment in the uterus (a
It is also known that (coustic landscape) is mainly composed of a low frequency periodic sound derived from the heart sound of the mother or heartbeat oscillation, and that the newborn baby after birth sleeps well with confidence when hearing such a sound. It is also widely practiced to generate similar periodic artificial sounds at the bedside of newborns to provide a means of sleep. It is known as actual measurement data that the utterance of the mother can be heard relatively well through the body tissue of the mother, although the fetus in the uterus has a high frequency cut in frequency.

[0008] Although lacking scientifically accurate proof,
The concept of so-called fetus has been widely supported since ancient times. Recently, as one of the activities, music activities to listen to music suitable for pregnant women have become popular. In this case, it is still controversial whether listening to this music to a pregnant woman has a mental effect, or whether it is effective to hear a music sound signal reaching the fetus from the air through the abdominal wall to the fetus. Most of the theory, however, is that the fetus is also listening to music, and that doing so has a certain effect. It is considered that it is a kind of preferable mother-infant communication that the mother stimulates such an acoustic stimulation to the fetus and that the mother knows the reaction.

[0009]

However, conventionally, the concept of the device such as a telemeter transmitter for collecting a fetal signal, a fetal heart sound detector for hearing sound or a Doppler fetal heart rate detector, a sound stimulating device for sound stimulation, and an operation effect similar to that of the fetus. The practical concept of making the fetus listen to music and the mother's voice for communication for mother-to-child communication lacked any organic association with each other. Therefore, for example, it is conceivable to use a mother's voice or preferable music instead of the buzzer sound or beep sound as a means for acoustic stimulation. However, a means device for effectively performing such a thing is lacking.

[0010] Conversely, even if the mother tries to get a general understanding of the health condition of the fetus, or if she can carry out a home NST for autonomous self-management, she has been working on a device for specialists or a device similar thereto, and has a fetal heart rate. They had the difficulty of obtaining the figure and having to interpret it themselves according to medical interpretation rules. Of course, the heart rate chart can be transmitted electronically to the management center or the attending physician for immediate diagnosis or processing. However, under the situation where the physiological condition of the fetus deteriorates every moment, it is conceivable that there is not enough time in the situation. In addition, for true autonomous self-management, a system is desired that allows pregnant women to treat themselves without any intervention of the center or the attending physician.

[0011] Furthermore, when music or sound signals are to be transmitted to a fetus in accordance with the above-mentioned concept of fetus or a similar concept,
With conventional means of doing this from above the abdominal wall via aerial sound waves, the effective acoustic signal does not reach the fetus in the uterus sufficiently. The amount of sound transmission between air and a biological tissue that is acoustically equivalent to water is approximately 1/30 at most and 1000/1000 at power due to the drop in acoustic impedance between the media. One digit. Sounds that are quite noisy in the air can also sound quite calm in the water.

Further, the acoustic attenuation of living tissue has a strong frequency dependence even in the audible frequency range due to its inherent viscosity, and the higher the frequency, the greater the attenuation. Therefore, sending sound through the air cannot be effective acoustic stimulation for the fetus. The acoustic environment for the fetus in the womb
erine acoustic landscape)
Is less than 100 Hz to several tens of Hz, such as the sound originating from the maternal cardiovascular or respiratory movements mentioned above, the maternal vocalizations, and the noise coming from intended or unintended movements. It has a strong main component on the frequency spectrum in a wide low frequency region.

On the other hand, it is presumed that the fetal auditory ability in the second half of pregnancy is not much different from that of a newborn baby in sensitivity and frequency characteristics. Has a large gap in the mid-high range.
In this blank region, the sensitivity of the fetus to acoustic stimulation is considered to be sufficiently higher than in the vicinity of the main component. In general, the sound signal of music or conversation fits just below the blank area in this sense, and if this is irradiated to the fetus effectively, the acoustic stimulation for AST purpose or prenatal-like purpose can be performed more effectively. That is, as will be described later, an object of the present invention is to effectively stimulate a fetus with an audible sound signal in a frequency domain which is not a main component in such an intrauterine acoustic environment, and to establish a means for that purpose. is there.

However, any of the conventional acoustic stimulators that have succeeded as the AST means emits a stimulating sound by directly contacting the abdominal wall of the mother, but any of the conventional direct contact acoustic stimulators. Neither can it transmit an audio signal having a wide range of gradations, such as music, human voice, and natural sound, with favorable fidelity with little distortion, and it is not designed so.

An example of a direct contact type acoustic stimulating device which is somewhat organically related to the fetal signal detecting means in order to know the fetal arousal response is JP-B-63-9449. However, even in this case, it only states that both functions are juxtaposed and automatic driving is performed in a time-sharing manner, and it does not mention at all the nature of the audible sound signal emitted for stimulation in the frequency spectrum. Absent.

The present invention is intended to solve the above-mentioned various difficulties and inconsistencies, and in particular, a device capable of establishing an effective stimulus transmission and confirmation of a reaction with a fetus under the autonomy of a pregnant woman. It is intended to realize the configuration of the means and its utilization technology. More specifically, as described above, an object of the present invention is to effectively stimulate a fetus with an audible sound signal in a frequency domain which is not a main component in such an intrauterine acoustic environment. Is to establish

[0017]

Means for Achieving the Object As means for achieving the above-mentioned purpose, in the present invention, one contact surface having a waterproof property and having a structure suitable for being mounted on the mother's abdominal wall is provided. Fetal signal detecting means for detecting a fetal signal through the contact surface, and audio sound wave emitting means for emitting audio sound waves in a substantially omnidirectional manner toward the fetus through the contact surface, Bidirectional fetus, characterized in that the audio sound emitting means is coupled to a driving means for driving the means to emit an acoustic signal which significantly comprises a frequency region which is not a major component in the fetal environment in the uterus. It is an object to realize a signaling device.

The apparatus of the present invention has many variations as embodiments as described later. In the above basic concept, the device can be realized even without relying on an electronic device at all. However, if electronic devices, electro-acoustic transducers (transducers), etc. are used effectively,
The most preferred embodiment of the invention can be obtained.

[0019]

According to the device of the present invention, acoustic stimulation of the fetus led by the mother is performed in an effective frequency band depending on the signal quality or sound quality, and the mother can also know the reaction of the fetus. You can get child communication. In addition, autonomous NST or AST of a pregnant woman at home can be easily performed with the help of some electronic devices.

[0020]

FIG. 1 is a partially broken cross-sectional view showing a device according to the most basic and simple embodiment of the concept of the present invention, in which a shallow, slightly flat bowl-shaped housing 1 is formed. A partition 2 is provided at the center, and a film 3 is hermetically adhered to the opening at the lower surface of the partition 2 with proper tension in a place where it was originally released. Has a room. Each of these air chambers is provided with an acoustic coupling port 4 which is connected to an earset 6 and a sound collector (megaphone) 7 via a voice tube (for example, a hard rubber tube) 8. . In this configuration, no electronic device, particularly an electronic device capable of amplifying signal power, appears anywhere.

As can be understood from such a structure, when the membrane surface is attached to the abdominal wall of the mother with a belt or a bandage (not shown), the air chamber on the right side of the figure becomes an air conduction type heart sound or fetus. It becomes a stethoscope similar to a heart sound microphone and constitutes a fetal signal detection means. The fetal heart sound can be heard by the mother via the earset 6, and the air chamber on the left side conversely picks up the sound or natural sound signal picked up by the sound collector. It becomes an audio sound wave radiating means which converts impedance and sends it into the inside of the mother's abdominal wall.

In this case, ignoring the loss of the loudspeaker, acoustic impedance conversion occurs in accordance with the ratio of the opening area of the sound collector 7 to the opening area of the left air chamber, and the sound pressure is increased. A bond is obtained. That is, if the mother speaks or sings toward the megaphone-shaped sound collector 7, a much higher-quality and higher-level sound reaches the fetus than can be heard over a long distance in the mother's body. Of course, if the sound collector 7 is brought in front of the speaker of the radio or the tape recorder, the music to be output is transmitted to the fetus. During or before or after that, the mother can continuously listen to the fetal heart sound via the earset 6, and can know the change, especially the change in the heartbeat cycle or heart rate.

Here, the thickness of the film 3 and the tension or distribution thereof in the attached state determine the frequency characteristics of the air chamber conduction system, particularly its high-pass / low-cut characteristics. As described above, in the intrauterine environment, it is possible to selectively provide the fetus with a voice or acoustic signal in the middle and high frequency range which is not a main component at all times. In the air chamber on the side forming the other part of the fetal heart sound stethoscope, the tension of the membrane 3 at the opening is adjusted to have a high-pass or band-pass characteristic adapted to the optimum frequency for fetal heart sound listening on the same principle. . In one preferred embodiment, the membrane 3 is a mylar or Kapton thin plate having a thickness of about 0.25 mm and is ultrasonically welded to the opening of the housing 1. However, the material, thickness, tension application method, mounting method, and the like of the film 3 are completely within the practical freedom.

When the lower surface of the membrane 3 is mounted in contact with the abdominal wall of the mother, an acoustic coupling agent is preferably interposed in order to prevent an air layer from intervening. As such an acoustic coupling agent, a gel of the same purpose commonly used in ultrasonic diagnosis, water or olive oil can be used, and a temporary adhesive for temporary bonding or a double-sided adhesive tape can be effectively used. . In order to be able to perform such attachment and detachment on a daily basis, and to withstand it, the membrane 3 and its surrounding structure must have a certain strength.

FIG. 2 shows another primitive embodiment, in which a screw-wound music box 8 is mounted as the simplest means for allowing a fetus to listen to the preferred music (the music box cover). Is abbreviated). The side where the fetal heart sound is heard is the same as the example of FIG. 1 except that the mounting surface of the music box is an acoustic radiation surface. Since the frequency spectrum of the sound of the music box is mainly in the middle or upper part of the audible range, it meets the above-mentioned purpose in making the sound heard by the fetus.

Although illustration and detailed description are omitted, an extremely small sounding body such as a tube, a string, a percussion instrument or a keyboard instrument is mounted in place of the music box, and the purpose is to allow the mother to play it by himself. Can be reached. Here, of course, it does not prevent the keyboard instrument from being electronic.

Although illustration and detailed description are omitted, an electronic device, particularly an electronic device having a signal power amplifying ability, such as an IC-type melody automatic sounder, may be replaced with an appropriate battery power source as an equivalent replacement of the music box. It is obvious that both the power switch and the power switch may be mounted.

Further, it is obvious that the side listening to the fetal heart sound also uses a microphone and an amplifier, and a general-purpose earphone or speaker may be used instead of the earset, and more advanced electronic devices such as a fetal heart rate meter. May be added.

[0029]

However, it is clear that the aforesaid non-electronic embodiments are only the most primitive implementations, especially for amplifiers capable of amplifying signals, and for digital and analog electronic and analog devices. A more preferred embodiment can be obtained by using the device technology.

FIG. 3 shows the most primitive example of the electronic embodiment, in which three bioelectrodes 9 are arranged on the lower surface of the housing 1 of the device mounted on the mother's abdominal wall. And
Using these, maternal abdominal wall-derived fetal ECG signals are collected. The collected signal is processed in a known manner by a supporting electronic device arranged in the apparatus, and finally output to the mother in the earphone 10 as a short beep synchronized with the fetal heartbeat. Even if the electrocardiographic signal is extracted and amplified and then supplied to the earphone as it is, it can be heard as a pulse sound. In this case, since the frequency spectrum of the mixed maternal electrocardiographic signals is considerably different from that of the fetus, it is easy to discriminate them by hearing. In one example of the preferred embodiment, the earphone 10
The gain up to about 1000 to 10000 times, and the pass band is about 20 Hz to 45 Hz.

FIG. 4 is a block diagram showing an electronic apparatus according to an embodiment of the present invention in which a fetal heart sound signal is collected and listened again. In this, one reversible electroacoustic transducer 1
1 is used for emitting audible sound and collecting fetal heart sound signals. Since these signals are separated in the frequency domain, such a combination is possible by splitting, that is, frequency division by a filter pair. As shown in the drawing, a fetal heart sound signal collected from a fetus is allocated to about 70 Hz or less by a filter 14 on the listening side, and an audible sound signal radiated toward the fetus is allocated to 150 Hz or more by a filter 13 on the radiation side. ing. As the reversible electroacoustic transducer 11, a piezoelectric type or an electrodynamic type can be used as long as it can be used as a microphone and a speaker, which is generally used for a handset of a telephone. Further, as the signal source 12, any melody sound source IC as described above, a microphone (not shown) connected to the outside, or a connector that electrically obtains a signal from another audio device can be used.

Here, it has been described that the signal is split into about 70 Hz or less and about 150 Hz or more. As a result, the crossover frequency is set to about 100 Hz. However, setting the crossover relationship between the pair of demultiplexing filters in this manner is a degree of freedom in design, and is not an essential component of the present invention. The sharpness of the cutoff of these filter pairs is also within the degree of freedom in design.

Although it has been described herein that one reversible converter is used for both radiation and detection purposes, this embodiment is also only one embodiment, and converters for both purposes may be separately provided as necessary. However, it is not a thing which hinders being integrated and arranged on the same contact surface, and such a case is also included in the category of the present invention.

The detection side does not hinder the use of an irreversible converter such as a carbon microphone or a condenser microphone or a variable reluctance microphone constituting a variable frequency transmitter instead of the reversible converter.

It is also possible to use a two-winding voice coil electrodynamic converter or a split-electrode piezoelectric converter which looks like a single reversible converter but has independent drive and detection electric terminals inside. Do not disturb.

It is also a preferred embodiment to reduce the load on the demultiplexing filter by inserting transmission / reception separation by a bridge or a hybrid circuit between the reversible converter having a single electric terminal and the demultiplexing filter pair. Yes, and does not hinder such embodiments.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiment described below is the most preferable embodiment considered by the inventors at the time of the invention. This configuration is shown in FIG. 5, and a block diagram is shown in FIG. In this case, an ultrasonic Doppler method is used for detecting a fetal signal, and a piezoelectric vibrator for transmitting and receiving the ultrasonic wave for the purpose is also used for emitting an audible sound in combination with an appropriate support structure.

5 and 6, the piezoelectric vibrator 21
Is a convex oscillator made of a known general-purpose PZT. The dimensions are, for example, about 1 mm thick, about 20 mm in diameter, and a radius of curvature of about 80 mm. This is about 2M in use
In cooperation with the CW Doppler transceiver circuit 22, which has a resonance point in Hz and is provided, a single-oscillator CW Doppler system having a known nominal center frequency of 2 MHz is formed for this purpose. The setting ultrasound beam, as is also known for this purpose, presents a divergent conical shape in which the movement of the fetal tissue, in particular the cardiovascular system, is captured if it is captured as a Doppler signal. . The piezoelectric vibrator 21 is coupled to the CW Doppler transmission / reception circuit 22 in terms of high frequency and transmits and receives ultrasonic waves as expected, but the direct current or the low With respect to the frequency, the signal is coupled to the output stage of the audio amplifier 23, and an audio signal of an audible frequency is given by the drive.

Since PZT, which is the material of the piezoelectric vibrator 21, has horizontal coupling that is not inferior to vertical coupling, in such a usage form, the applied audio signal expands and contracts in the thickness direction and in a direction parallel to the plane. Also stretch. Here, since the vibrator on the spherical shell surface is firmly adhered to and held by the mechanical clamp member (ring frame) 20,
The radial expansion / contraction motion stress is converted into a motion for displacing the center portion back and forth (vertically in FIG. 5). This conversion principle is a known general-purpose thing in ceramic earphones and ceramic speakers. As a result, the piezoelectric vibrator 21 can emit an acoustic signal in the audio region at the same time while transmitting and receiving ultrasonic waves for the Doppler system,
It performs a purposeful operation according to the spirit of the present invention.

In any case, in the embodiment of the present invention, the audible frequency acoustic signal is radiated from such a small opening, so that the radiation is substantially omnidirectional. This is preferred because it obviates the need to consider where the target fetus is and which one it is facing.

As described above, in addition to the method of providing a mechanical clamp member (ring frame) as a side surface restraining means for restraining the PZT convex oscillator from the side surface and converting radial expansion and contraction into vibration in the normal direction of the oscillator surface. Alternatively, the same purpose can be achieved by imposing a heavy back load on the vibrator and directly utilizing the vibration in the thickness direction.

[0042] Even if a flat PZT disk or square plate is used, a brass or stainless steel thin plate which is difficult to expand and contract is adhered to one side of the whole surface, even if a flat PZT disk or square plate is used. If so, it is possible to realize a structure that converts expansion and contraction in the plane direction into vibration in the normal direction perpendicular to the plane. This is also a technique commonly used in piezoelectric buzzers and speakers. In this way, even in a structure in which a thin back load is applied to a PZT plate, resonance in the thickness direction obtained at a specific frequency can be used for transmission and reception of ultrasonic waves if the thickness and acoustic propagation constant are properly considered. .

Of course, even if two PZT thin plates are stuck together in order to adopt a bimorph structure, and they are driven so that expansion and contraction are in opposite directions, a planar structure that converts expansion and contraction in the radial direction into expansion and contraction in the normal direction is used. can get. In this case as well, the electrical coupling at high frequencies can be set independently of the audio region, so that the entire thickness resonance can be utilized for transmission and reception of ultrasonic waves.

In FIG. 7, the fetal heart rate meter 23 selectively extracts a fetal heart rate signal from the obtained ultrasonic Doppler fetal signal, and further calculates a fetal heart rate value from this. Such a fetal heart rate meter is generally used as an autocorrelation type one, but here, this is implemented by a one-chip CPU or the like so as to be suitable for battery operation inside the portable device.
This is basically found in Japanese Patent Publication No. 56-7592, etc., which is one of the prior inventions of one of the inventors of the present invention. However, if it is appropriate for the purpose of use, an apparatus by another method can be adopted.

The thus-obtained fetal heart rate data is converted into an audio frequency tone signal in the variable frequency oscillator 24. As an example, if the heart rate value is 100, 1K
Hz, 140K is 1.4KHz, 200 is 2KH
Performs a conversion that is easy for the ear to understand, such as z. These are added and amplified by the audio amplifier 25 for the earphone 10 and supplied to the earphone 10 so that the mother can listen to the Doppler heartbeat signal by superimposing the tone signal on the mother at the same time. In this configuration, the mother can hear both the large change and the minute change in the pitch of the tone signal by ear, and can know the minute fluctuation of the heart rate and the change of the baseline.

The mixed sound signal supplied to the earphone 10 is simultaneously supplied to the telemeter transmitter 28 as needed, and is used for display, recording, or storage in another device (not shown) which is located at a slightly remote place. Transmitted for use in In addition to such an instant transmission, although not described in detail, a display means for displaying digital data of a fetal signal or fetal heart rate value, and a mass memory for temporarily storing or recording the data within the same housing are also provided. Means
They may be provided as needed.

The battery 29 serves as a power source for all electronic devices in the same enclosure, with a stabilized power supply circuit (not shown) if necessary.

Thus, the apparatus shown in FIG. 7 is housed in one housing including the battery, and is mounted on the abdominal wall of the mother with a belt, a bandage or something. For this reason, the housing has an outer shape that is shorter than the diameter and has no corners. A typical embodiment is a flat, approximately 7 cm diameter, less than 3 cm tall, looking like the lower half of a offering rice cake. As mentioned earlier,
The side of each or integrated transducer for the emission of audio signals and the acquisition of fetal signals on the bottom of this housing is attached to the maternal abdominal wall, while the acoustic coupling of the air layer A gel or suitable acoustic coupling agent is interposed in order to ensure this without any intervention.

[0049]

According to the present invention, the mother-initiated acoustic stimulation of the fetus is performed in an effective frequency band with a preferable signal quality or sound quality, and the mother can also know the reaction of the fetus. Is obtained. If some electronic devices are used, autonomous NST or AST of a pregnant woman at home can be easily performed.

[Brief description of the drawings]

FIG. 1 is an external view including a partial cross section showing a most primitive embodiment of the present invention.

FIG. 2 is an external view showing another primitive embodiment of the present invention.

FIG. 3 is an external view showing an abdominal wall-guided fetal electrocardiographic device in an embodiment of the present invention.

FIG. 4 is a block diagram showing a case where one reversible converter is used in the embodiment of the present invention.

FIG. 5 is a sectional view of a main part when one ultrasonic transducer is used in the embodiment of the present invention.

FIG. 6 is a block diagram illustrating an ultrasonic Doppler transceiver according to a most preferred embodiment of the present invention.

FIG. 7 is a block diagram showing the entire electronic device according to the most preferred embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Partition wall 3 Film 4 Acoustic coupling port 5 Voice tube 6 Ear set 7 Sound collector (or megaphone) 8 Music box 9 Bioelectrode 10 Earphone 11 Reversible electroacoustic transducer 12 Signal source 13 High-pass filter 14 Low-pass filter 20 Ring frame 21 Ultrasonic transducer 22 CW Doppler system 23 Fetal heart rate monitor 24 Variable frequency oscillator 25 Audio amplifier for earphone 26 Audio amplifier for radiation 28 Telemeter transmitter 29 Battery

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-170445 (JP, A) JP-A 64-27540 (JP, A) JP-A 60-176630 (JP, A) 65291 (JP, U) Special Table 59-500650 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61B 8/00 A61B 7/04

Claims (16)

(57) [Claims] 1. A fetal signal detecting means for detecting a fetal signal via one contact surface having a waterproof property and having a structure suitable for being mounted on a mother's abdominal wall, and the contact surface. Audio sound emitting means for emitting audio sound waves in a substantially omnidirectional manner toward the fetus through the audio wave sound emitting means, the audio sound emitting means significantly reducing a frequency region that is not a main component in the fetal environment in the uterus. A bi-directional fetal signaling device, characterized in that said device is coupled to driving means for driving said means to emit an acoustic signal including said signal. 2. The two-way fetal signal device according to claim 1, wherein both the fetal signal detection means and the audio sound wave emitting means do not include an electronic device capable of amplifying signal power. The bidirectional fetal signal device. 3. The bidirectional fetal signal device according to claim 1, wherein at least one or both of said fetal signal detecting means and said audio sound wave emitting means include an electronic device having a signal power amplifying ability. The bidirectional fetal signaling device, characterized by slackening. 4. The bidirectional fetal signal device according to claim 1, wherein said fetal signal detecting means includes at least three bioelectrodes for detecting a fetal electrocardiographic signal and necessary supporting electronic device means. The bidirectional fetal signaling device, characterized in that it is constructed. 5. The bi-directional fetal signal device according to claim 1, wherein said fetal signal detecting means includes at least one electro-acoustic transducer for detecting a fetal-derived acoustic signal including a fetal heart sound signal, and further comprising: The bidirectional fetal signaling device is characterized in that it comprises various supporting electronic device means. 6. A bi-directional fetal signal device according to claim 1, wherein said fetal signal detecting means comprises at least one device for observing the movement of fetal tissue by ultrasonic Doppler method.
The two-way fetal signal device comprises ultrasonic transmitting and receiving means and necessary supporting electronic means. 7. The bidirectional fetal signal device according to claim 1, 3 or 6, wherein the ultrasonic wave transmitting / receiving means and the audio frequency sound wave emitting means are used in a thickness resonance mode at a used ultrasonic frequency, A bidirectional fetal signal device characterized in that a piezoelectric vibrator having at most a pair of electrodes and an electric terminal at a portion used in a non-resonant mode at a usable audio frequency is shared. 8. The bidirectional fetal signal device according to claim 7, wherein the piezoelectric vibrator is made of a flat or curved thin plate made of a material such as PZT, which has an electromechanical coupling in both vertical and horizontal directions. A back load means or a side restraint means for effectively converting radial vibration at an audible frequency of the vibrator into vibration in a normal direction of the vibrator surface, wherein the bidirectional fetus is provided. Signaling device. 9. The bidirectional fetal signal device according to claim 1, wherein one reversible electro-acoustic transducer detects a fetal-derived acoustic signal including a fetal heart sound signal, and wherein the means is substantially directed toward the fetus. A bidirectional fetus characterized by comprising filter means for omnidirectionally radiating audio sound waves, and for performing detection and radiation in a frequency-division manner. Signaling device. 10. The bidirectional fetal signal device according to claim 1, wherein the acquisition of the fetal signal is stopped while the audio sound wave is radiated. The bidirectional fetal signal device. 11. A bi-directional fetal signal device according to any of claims 1 and 3 to 9, wherein the device is adapted to continue collecting fetal signals while radiating audio sound waves. A bidirectional fetal signal device comprising: means for removing or eliminating interference components derived from simultaneously radiated audio sound waves from a collected fetal signal. 12. Filter means for receiving an audio signal from another device as an external input, for selecting a frequency of the audio signal received by the receiving means and supplying the selected signal to the audio sound wave emitting means. The bidirectional fetal signaling device according to claim 1, characterized by comprising: 13. The bidirectional fetal signaling device according to claim 1, further comprising means for acquiring a mother's speech as an external input and transmitting the acquired audio to the audio sound wave emitting means. 14. The bi-directional fetal signal device according to claim 1, further comprising a voice tube, an earphone or a speaker for a mother to listen to the collected fetal signal. 15. A means for selectively extracting a fetal heart rate signal from the collected fetal signal, determining a fetal heart rate value, and displaying, recording, storing or transmitting the same to another. 16. The method as claimed in claim 1, wherein:
The bidirectional fetal signaling device according to any of the preceding claims. 16. Suitable for mounting on a mother's abdominal wall with a belt or a bandage, etc., the height is significantly smaller than the diameter,
It has a flat and non-sharp outer casing, forms an acoustic coupling with the abdominal wall of the mother via an acoustic coupling agent on the bottom surface of the casing, and includes an electronic circuit required therein and a battery of at most one system. Power supply means, wherein the battery power supply means is configured to be commonly used for supplying power to each electronic circuit for detecting a fetal signal and emitting audio sound waves. 16. The bi-directional fetal signaling device according to any of claims 1, 3 to 15, wherein: