JP2613633B2 - Pressure 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.

2. Description of the Related Art 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. An apparatus for detecting such a pressure pulse wave generally includes a pressure sensor pressed on the surface of a living body and directly above an artery, and detects a pressure pulse wave generated from the artery by the pressure sensor. However, since the pressure portion of the pressure sensor is larger than the diameter of the artery, sufficient information may not be obtained.

On the other hand, it has been considered to detect a pressure pulse wave at a plurality of points at intervals smaller than the artery diameter on a line intersecting the artery. For example, Japanese Patent Application No. 62-130879 (JP-A-63-130879)
No. 293424), when trying to select a point where the influence of the tension of the wall of the artery is small and the pressure can be measured close to the blood pressure in the arterial tract, or in Japanese Patent Application No. 63-87.
This is the case where the degree of arteriosclerosis is to be measured, as noted in Japanese Patent Application Laid-Open No. 720 (Japanese Patent Application Laid-Open No. 1-259836).

SUMMARY OF THE INVENTION As described above, when detecting pressure pulse waves at a plurality of points on an artery, the number of measurement points on the artery cannot be sufficiently obtained, particularly when the diameter of the artery is relatively small. Was. That is, the pulse wave sensor used in the above-described conventional pressure pulse wave measurement includes a thin pressure-receiving portion (pressure detecting element) that generates distortion due to pressure, and a relatively thick semiconductor having high rigidity using a photo-etching technique. It is configured by forming a plurality of recesses in the thickness direction from one surface of the substrate.However, when the recesses and the recesses are brought close to each other, an area for forming a conductor pattern cannot be obtained, and the rigidity of the semiconductor substrate decreases. Since there is a possibility that the pressure cannot be measured accurately, the distance between the pressure receiving parts cannot be approached to a certain degree, for example, 0.5 mm or less.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pressure pulse wave detection device having a high density of pressure pulse wave measurement points per unit length.

Means for Solving the Problems In order to achieve the above object, the gist of the present invention is a pressure pulse wave detection device that detects a pressure pulse wave generated from an artery of a living body from a plurality of positions on the artery. (A) a body attached to the living body with a pressing surface pressed against the skin of the living body; (b) a pressing plate having flexibility and fixed to the pressing surface of the main body; c) a microlens array provided in the main body in parallel with the pressing plate and with a predetermined gap therebetween; and (d) a light source device for irradiating irradiation light toward the pressing plate through the microlens array.
(E) receiving the reflected light reflected by the pressing plate through the microlens array, at intervals at which at least three points are located within the diameter of the artery along the direction crossing the artery on the pressing plate; A light receiving sensor array for detecting pressure pulse waves at the plurality of points based on reflected light from the plurality of arranged points.

In this way, light from the light source device is irradiated on the pressing plate through the microlens array arranged in parallel with the pressing plate and with a predetermined gap therebetween, and the light is reflected by the pressing plate. Light is received by the light receiving sensor array through the micro lens array. As a result, the minute displacement of the pressure plate is optically grasped based on the reflected light from a plurality of measurement points at minute intervals on the pressure plate, and the pressure pulse waves are respectively detected based on the minute displacement of the pressure plate. Is done.

Therefore, there is no need to provide a wiring conductor pattern on the main body, and since there is no restriction on the thickness and a member having high rigidity can be used, and there is no problem of reduction in rigidity, a plurality of concave portions are formed on one surface of the semiconductor substrate. As compared with the conventional case, a pressure pulse wave detecting device having a sufficiently high density of pressure pulse wave measurement points per unit length can be configured.

Embodiment Hereinafter, an embodiment 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 sensor 12 includes 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 material having high rigidity such as hard resin, metal, ceramic or the like. As shown in detail in FIG. 2, the first member 32, the second member 34, and the third member 36 are provided.
Are stacked and fixed to each other. The first member 32 and the second member 34 are respectively formed with rectangular holes 38 and 40 penetrating in the thickness direction except for the peripheral portion, and the third member 36 is formed with a concave portion 42.

The pressing surface 44 of the first member 32 has flexibility such as a relatively thin metal plate or resin plate of about 2/100 mm or a relatively thin stainless steel plate plated with gloss. The pressing plate 46 is stuck. A microlens array 48 in which a plurality of lenses are integrally formed in a row is disposed between the first member 32 and the second member 34 in a state parallel to the pressing plate 46 and at a predetermined interval. Has been established.
Further, between the second member 34 and the third member 36, an alumina substrate 49 to which the semiconductor chip 50 is fixed is disposed at a predetermined distance from the microlens array 48. The alumina substrate 49 is provided with wiring for electrically connecting to the semiconductor chip 50. On the semiconductor chip 50, a pair of light emitting elements and light receiving elements located near each other are arranged in a row corresponding to each lens of the micro lens array 48. The semiconductor chip 50 is manufactured by a semiconductor integrated circuit manufacturing technique, and includes a selectively grown P-type or N-type grown layer on a compound semiconductor substrate, or a selectively provided doping layer if necessary. Light emitting elements and light receiving elements are arranged at intervals of, for example, 100 μ by a combination of layers and the like.

In the microlens array 48, Fresnel lenses are formed at intervals of, for example, 100 μ using an electron beam exposure technique. For example, a microlens array is formed by coating an electron beam resist on a transparent substrate such as plastic or glass, performing prebaking, scanning the electron beam concentrically using a drawing apparatus, and then performing a development process. 48 are manufactured.

Therefore, the monochromatic light emitted from the light emitting element on the semiconductor chip 50 passes through the microlens array 48 and the pressing plate.
The light is focused on 46 at a predetermined spot diameter. The condensing points on these pressing plates 46 are at intervals similar to the center intervals of the lenses constituting the microlens array 48, for example, about 100 μm. The light reflected by the pressing plate 46 passes through the microlens array 48 again and is received by the light receiving element of the semiconductor chip 50. The distance between the pressing plate 46 and the microlens array 48 is set slightly larger than the focal length of the microlens array 48, and the light-converging point is slightly shifted upward from the pressing plate 46. The amount of reflected light received by the light receiving element of the semiconductor chip 50 is changed in relation to the displacement of the semiconductor chip 50. Since the pressing plate 46 is flexed and vibrated by the pressure pulse wave generated from the radial artery 30 in synchronization with the heartbeat, the light receiving element of the semiconductor chip 50 transmits a signal representing the amount of reflection received, in other words, the pressure pulse wave signal SM. Output. Since the pressure pulse wave sensor 12 is mounted so that a plurality of measurement points are located along the direction crossing the radial artery 30 at intervals at which at least three points are located within the radius of the radial artery 30, the radial artery 30 , A pressure pulse wave is detected at measurement points at intervals of, for example, 100 μ. FIG. 3 shows an example of a pressure pulse wave represented by the pressure pulse signal SM. Therefore, in the present embodiment, the semiconductor chip 50 functions as a light source device and a light receiving sensor array.

In the A / D converter 52, the pressure pulse wave signal SM output from the light receiving element of the semiconductor chip 50 is amplified, A / D converted, and supplied to the control device 56. The control device 56 includes a CPU, a ROM,
A microcomputer including a RAM, which processes an input signal according to a program stored in advance. For example, while determining the optimal pressing force from the pressure pulse wave signal SM read while changing the pressing force of the main body 18, the pressure pulse wave signal SM representing the pressure pulse waves at a plurality of measurement points is close to the center of the radial artery 30. The signal from the measurement point is selected, and the systolic blood pressure value and the diastolic blood pressure value are sequentially monitored. Alternatively, as described in Japanese Patent Application No. 63-87720 (Japanese Patent Application 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, The result is output to an output device (not shown).

As described above, according to the present embodiment, it is not necessary to provide a wiring conductor pattern on the main body 18, and a highly rigid member can be used with no restriction on the thickness of the main body 18. As described above, the reduction in rigidity does not pose a problem, and light-emitting elements and light-receiving elements are arranged at small intervals in a semiconductor chip 50 manufactured using a semiconductor integrated circuit manufacturing technique, and are manufactured using an electron beam exposure technique. Since the microlens array 48 is used, a pressure pulse wave detection device having a sufficiently high density of pressure pulse wave measurement points per unit length can be configured.

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

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

For example, in the above-described embodiment, the pressing plate 36 is a single sheet. However, a slit may be provided between the measuring points (reflection points) of the pressing plate 36, or may be separated from each other so that mechanical The interference may be prevented.

In the above-described embodiment, the light receiving element and the light emitting element are integrally provided on the semiconductor chip 50. However, the chip provided with the light receiving element and the chip provided with the light emitting element are formed separately. The light emitted from one light emitting chip may be split by a beam splitter and supplied to the plurality of measurement points. This light is desirably monochromatic light, and an LED or a semiconductor laser element can be used as the light emitting chip or the light emitting element.

Further, the semiconductor chip 50 in the above-described embodiment may be provided integrally with a drive circuit for switching the light emitting elements, a multiplexer for time-dividing the signals output from the respective light receiving elements, and the like.

The main body 18 is driven in the pressing direction by the diaphragm 22.
Drive device to move in the direction crossing 30 and radial artery 30
A rocking positioning device for positioning a rocking position about one axis parallel to the shaft may be provided.

Further, the micro lens array 48 in the above-described embodiment is used.
Is formed by subjecting a resist on a transparent substrate to electron beam exposure. As shown in FIG. 4, a predetermined pattern is formed in a two-dimensional waveguide 62 formed on one surface of a lithium niobate substrate 60. The micro lenses 64 may be formed at 100 μ intervals by thermally diffusing Ti or the like.

Further, in the above-described embodiment, the pressure pulse wave generated from the radial artery 30 is described as being detected, but the main body 18 of the pressure pulse wave detection head 12 detects the pressure pulse wave generated from another artery. It may be pressed by another artery for detection.

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 configuration of the main body of the pressure pulse wave detecting head of the embodiment of FIG. FIG.
It is a figure which shows the example of the pressure pulse wave represented by the pressure pulse wave signal output from the pressure pulse wave signal output device of the figure. FIG. 4 is a perspective view showing a microlens array according to another embodiment of the present invention. 18: body, 30: radial artery (artery) 44: pressing surface, 46: pressing plate 48: microlens array 50: semiconductor chip

Claims (1)

(57) [Claims] 1. A pressure pulse wave detecting device for detecting a pressure pulse wave generated from an artery of a living body from a plurality of positions on the artery, comprising a pressing surface pressed against the skin of the living body, and attached to the living body. A main body to be provided; a pressing plate having flexibility and fixed to a pressing surface of the main body; a microlens array provided in the main body in parallel with the pressing plate and at a predetermined interval; A light source device for irradiating the irradiation light toward the pressing plate through a microlens array, and receiving the reflected light reflected by the pressing plate through the microlens array, respectively, in a direction crossing the artery on the pressing plate. And a light-receiving sensor array for detecting pressure pulse waves at the plurality of points based on reflected light from the plurality of points arranged at intervals at which at least three points are located within the diameter of the artery. Pulse-wave detecting device.