JP2613634B2 - Pulse wave detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for detecting a pressure pulse wave generated in an artery of a living body from a plurality of positions on the artery.

Conventional technology and its problems Pressure pulse waves generated from arteries in synchronization with the heartbeat
Various information indicating the state of the circulatory organ, such as the activity state of the heart, the blood pressure value, the degree of arteriosclerosis, etc., is included. In order to detect such a pressure pulse wave, a pressure plate is provided which is pressed against the epidermis of the living body, and the vibration of the bending of the pressure plate is detected at a plurality of detection points on the pressure plate in a non-contact manner. Thus, there has been provided a pulse wave detecting device of a type in which a pressure pulse wave generated from an artery under the epidermis is detected at a plurality of locations along a direction intersecting the artery.

However, in such a conventional apparatus, generally, since the pressing plate is formed as a single plate, vibrations detected at each measurement point of the pressing plate interfere with each other, so that a detected pressure pulse wave is generated. In some cases, the accuracy of the above was not sufficiently obtained.

An object of the present invention is to improve the accuracy of pressure pulse wave detection by blocking mutual interference between a plurality of measurement points for detecting a pressure pulse wave by being pressed against the epidermis of a living body against the background described above. It was done as.

Means for Solving the Problems In order to achieve the above object, the gist of the present invention is to provide a pressing plate which is pressed against the skin of a living body, and the vibration of the bending of the pressing plate is caused by a plurality of vibrations on the pressing plate. By non-contact detection at the detection points, pressure pulse waves generated from the artery under the epidermis are detected at a plurality of locations along the direction intersecting the artery and at least three points within the diameter of the artery. In the pulse wave detection device, a slit or a groove for blocking mutual interference of vibrations is provided between the vibration detection points of the pressing plate.

In this manner, since a slit or a groove for blocking mutual interference of vibrations is provided between the vibration detection points of the pressing plate pressed against the skin of the living body, a plurality of vibration detections can be performed. The deflection vibration of the pressing plate detected between the points does not interfere with each other. Therefore, according to the present invention, pressure pulse waves detected at a plurality of locations are each accurately detected,
The effect of improving the accuracy of pressure pulse wave detection is obtained.

Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a pressure pulse wave detection head 12 is detachably attached to a wrist 10 by a band 14. The pressure pulse wave detection head 12 has a bottomed cylindrical housing 16 and a housing 16.
And a diaphragm 22 that is provided between the housing 16 and the main body 18 to support the main body 18 and form a pressure chamber 20 in the housing 16. When supplied to the pressure chamber 20 via the pressure control valve 26, the main body 18 is pressed onto the radial artery 30 located on the radius 28.

The main body 18 is made of a hard resin, metal, ceramic, or the like, and is made of a highly rigid material having a thickness of about several mm or about several tens mm. As shown in detail in FIGS. And a recess 33 formed except for the peripheral portion of the pressing surface 32, and a plurality of through holes 34 opened in the recess 33 and arranged along one direction.

The pressing surface 32 of the main body 18 has a flexible pressing plate 36 such as a relatively thin metal plate or plastic plate of about 2/100 mm or a relatively thin stainless steel plate plated with gloss. Is affixed. This pressing plate 36
As shown in detail in FIGS. 4 and 5, a plurality of slits 35 are formed between the portions (indicated by broken lines in FIG. 4) corresponding to the through holes 34. While penetrating in the thickness direction, in a state substantially parallel to the radial artery 30 in a state where the pressing plate 36 is pressed against the epidermis of the living body, that is, in the width direction of the pressing plate 36, the end of the pressing plate 36 does not impair the durability. A predetermined distance from the edge is formed along the width direction. Therefore, in a state where the pressing plate 36 flexes and vibrates in response to the pulsation of the radial artery 30, each portion corresponding to the through hole 34, that is, each vibration detection point on the pressing plate 36 is separated by the slit 35. Therefore, the vibrations detected at the detection points are preferably prevented from interfering with each other.

The pressing surface 32 of the main body 18 has a through hole 34 and a concave portion.
33 Ventilation groove to eliminate pressure difference between inside and atmosphere 38
Are formed. Further, the interval between the through holes 34 corresponds to the interval between the measurement points of the pulse pressure wave, the interval is sufficiently smaller than the diameter of the radial artery 30, for example, determined to be a value of about 0.2mm, the radial artery 30 At least three to five measurement points are located within the radius.

A plurality of optical fibers 40a, 40b, 40c
One end of each of them is fitted, and the end faces of these one end are opposed to the pressing plate 36. The other ends of the plurality of optical fibers 40a, 40b, 40c
Fixed to 2. Since the pressure pulse signal output device 42 is similarly configured for each of the plurality of optical fibers 40a, 40b, 40c,..., The optical fiber 40a will be described below. The pressure pulse wave signal output device 42 includes a laser light source 44 that outputs laser light having a uniform phase, a convex lens 46 that makes the road output from the laser light source 44 parallel light, and an unpolarized beam for splitting the beam. A splitter 48 and a mirror for returning light reflected by the non-polarizing beam splitter 48
49, a convex lens 50 for making the light passing through the non-polarizing beam splitter 48 incident on the other end face of the optical fiber 40a, and a photosensor 52 for receiving light extracted by the non-polarizing beam splitter 48 out of reflected light propagating through the optical fiber 40a.
And the pressure pulse wave signal SMa based on the output signal of the photo sensor 52.
And a pressure pulse wave detection circuit 54 that outputs a signal.

In the pressure pulse wave signal output device 42 configured as described above, the portion of the pressing plate 36 corresponding to the opening of the through hole 34 located at the left end in FIG. 2, that is, faces the distal end surface of the optical fiber 40a. A pressure pulse wave signal SMa representing a pressure pulse wave acting on the portion is output from the pressure pulse wave detection circuit 54. That is, of the laser light output from the laser light source 44, one laser light reflected by the non-polarization beam splitter 48 is reflected by the mirror 49, passes through the non-polarization beam splitter 48, and is received by the photosensor 52. Of the laser light output from the laser light source 44, the other laser light transmitted through the non-polarizing beam splitter 48 is applied to a pressing plate 36 via an optical fiber 40a known as a rod lens, and the pressing plate 36 After being reflected, it is again guided to the optical fiber 40a and returned to the non-polarizing beam splitter 48. Then, the light is reflected by the non-polarizing beam splitter 48 and received by the photosensor 52. For this reason, the laser light received by the photosensor 52 is light reflected by the mirror 49, that is, interference light between the reference light and the light reflected by the pressing plate 36, that is, the measurement light. The phase of the interference light is changed by the change in the optical path of the measurement light due to the bending corresponding to the pressure acting on the light. The pressure pulse wave detection circuit 54 sequentially counts the phase change of the interference light corresponding to the minute displacement of the pressing plate 36 every predetermined small minute unit time, and based on the counted value, the cycle of the pressing plate 36 And outputs a pressure pulse wave signal SMa representing the pressure pulse wave that is acting.
FIG. 6 shows one cycle of the pressure pulse wave represented by the pressure pulse signal SMa.

As described above, the pressure pulse wave signals SMa, SMb, SMC,... Representing the pressure pulse waves at the respective measurement points located on the radial artery 30.
Is supplied from the pressure pulse wave signal output device 42 to the control device 56, the control device 56 processes the input signal in accordance with a program stored in advance, for example, as disclosed in Japanese Patent Application No. 62-130879 (Japanese Unexamined Patent Application Publication No. 63-130879). No. 293424), a pressure pulse wave at a measurement point which is not affected by the tension of the vessel wall of the artery is selected to continuously monitor the blood pressure value.
As described in JP 87720 (Japanese Patent Laid-Open No. 1-259836), the arterial stiffness is measured based on the pressure pulse wave obtained while changing the pressing force of the main body 18, and the result is output to an output device (not shown). Is output.

As described above, in the present embodiment, the vibration caused by the bending of the pressing plate 36 at each vibration detection point where the mutual interference is blocked by the slit 35 on the pressing plate 36 is caused by the optical fibers 40a, 40
b, 40c .... pressure pulse generated from the radial artery 30 by being detected based on the reflected light reflected at each vibration detection point, that is, the phase difference between the interference light between the reference light and the measurement light. Waves are detected. Therefore, according to the present embodiment, the slits 35 are provided between the respective vibration detection points in the pressing plate 36, and the vibrations detected at the respective vibration detection points are preferably prevented from interfering with each other. In addition, the effect of improving the accuracy of pressure pulse wave detection as compared with the conventional device can be obtained.

Further, in a conventional apparatus in which a pressure receiving portion is formed by forming a concave portion on a semiconductor substrate by using a photo-etching technique and a wiring conductor pattern is provided to detect a pressure pulse wave, a wiring conductor pattern is provided. In order to secure an area and obtain a sufficient rigidity of the semiconductor substrate, it was necessary to form the plurality of pressure receiving portions with a certain distance therebetween. There is no need to provide a wiring conductor pattern between the provided through holes 34, and furthermore, there is no restriction on the thickness of the main body 18, and a member having high rigidity can be used. Therefore, the through holes 34 can be formed close to each other. Therefore, there is an advantage that the density of the pressure pulse wave measurement points per unit length can be sufficiently increased.

Further, according to the pulse wave detection device of the present embodiment, there is no electric circuit in a portion directly in contact with the skin, and therefore, there is an advantage that high safety can be obtained.

Next, another embodiment of the present invention will be described with reference to the drawings.

In the above-described embodiment, the slits 35 are provided between the respective vibration detection points corresponding to the through holes 34 of the pressing plate 36. However, instead of this, a narrow groove as shown in FIG.
60 may be formed. At this time, the depth dimension of the narrow groove 60 is made as large as possible within a range where the durability of the pressing plate 36 is sufficiently obtained. In this embodiment, too,
By virtue of 60, mutual interference of vibrations between the respective vibration detection points is sufficiently cut off.

Also, as shown in FIG. 8, the slit 35 may be open to the side edge of the pressing plate 36.

As mentioned above, although one Example of this invention was described based on drawing, this invention is applied also in another aspect.

For example, the main body 18 in the above-described embodiment is configured to be driven in the pressing direction by the diaphragm 22, but in addition to this, a driving device that moves in a direction intersecting with the radial artery 30, A swing positioning device for positioning the swing position about one axis may be provided.

In the above-described embodiment, one optical fiber 40a, 40b, 40c,... Is provided for each pressure pulse wave measurement point, but a single bundle of optical fibers is provided. May be.

In the above-described embodiment, the pressure pulse wave is detected based on the phase difference of the interference light. However, the pressure pulse wave is detected based on a change in the amount of reflected light generated in association with the bending of the pressing plate 36. You may make it. In this case, for example, one or two or more irradiation light optical fibers and a light receiving optical fiber bundled around the outer periphery thereof are formed. One bundle of optical fibers is used for each pressure pulse wave measurement point, and the reflected light guided by the light receiving optical fiber is received by the optical sensor, so that a pressure pulse wave signal is output. The light source at this time may be a light source such as an LED or a lamp as long as the light output is constant.

In the above-described embodiment, the pressure pulse wave is detected based on the phase difference of the interference light. However, the phase difference due to the Doppler shift may be detected using optical heterodyne. That is, a laser light source that outputs laser light of two orthogonal frequencies is used, the two-frequency laser light is separated into two optical paths of measurement light and reference light, the optical path of the reference light is fixed, and the optical path of the measurement light is In addition to the optical path reflected by the pressing plate, a measurement beat signal is created by combining the reflected measurement light and the reference light, and a reference beat signal is created by combining two orthogonal frequencies immediately after being output from the laser light source. And outputs a pressure pulse wave signal based on the shift between the measured beat signal and the reference beat signal.

In the above-described embodiment, the vibration of the pressing plate 36 is detected optically, but may be detected electromagnetically.

Further, in the above-described embodiment, the pressure pulse wave generated from the radial artery 30 has been described as being detected, but the pressing plate 32 may be used to detect a pressure pulse wave generated from another artery. It may be pressed by the artery.

The above is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the spirit thereof.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration of one embodiment of the present invention. FIG. 2 is a diagram for explaining in detail the configurations of the pressure pulse wave detection head and the pressure pulse wave signal output device of the embodiment of FIG. FIG. 3 is a view showing a pressing surface of the main body in the pressure pulse wave detecting head of the embodiment of FIG. FIG. 4 is an enlarged plan view of the pressing plate of FIG. FIG. 5 is an enlarged view showing a cross section of the pressing plate of FIG. 2 along a direction perpendicular to the radial artery. FIG. 6 is a diagram showing an example of a pressure pulse wave represented by a pressure pulse signal output from the pressure pulse signal output device of FIG. FIG. 7 is a view corresponding to FIG. 5 in another embodiment of the present invention. FIG. 8 is a view corresponding to FIG. 4 in another embodiment of the present invention. 36: Pressing plate 35: Slit 60: Narrow groove

Claims (1)

(57) [Claims] A pressure plate which is pressed against the epidermis of a living body, wherein a flexural vibration of the pressure plate is detected in a non-contact manner at a plurality of vibration detection points on the pressure plate, whereby the artery under the epidermis is detected. A pulse wave detection device that detects a pressure pulse wave generated from a plurality of points along a direction intersecting the artery and at least three points within a diameter of the artery, between the vibration detection points of the pressing plate. A pulse wave detecting device provided with a slit or a groove for blocking mutual interference of vibrations.