JPS61238225A - Pulse detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field This invention is a finger compression type electronic blood pressure monitor (finger electronic blood pressure monitor).
This invention relates to pulse wave detectors used in applications such as pulse wave detectors.

(B) Prior Art Conventionally, pulse wave detectors have been known that project light onto finger arteries and obtain pulse wave signals based on the amount of received light.

The principle of this pulse wave detector is that, as shown in Fig. 6, a light emitting element (LED) L is provided on the side of the finger F, and a light receiving element (phototransistor) is provided on the side of the other finger that holds the finger F between them. P
T was provided, and the light receiving element PT received the light transmitted through the artery.

(C) Problems to be Solved by the Invention The inventors of this application have developed an electronic blood pressure monitor that measures the finger by compressing the finger with a pneumatic cuff in order to improve operability and reduce the size. He created an electronic blood pressure monitor and filed a separate application. This electronic finger sphygmomanometer detects a pulse wave signal and applies a predetermined algorithm to its amplitude value, for example, and requires highly accurate pulse wave detection.

However, the conventional pulse wave detector described above transmits light over a distance equivalent to the width of a finger, and therefore does not have sufficient sensitivity.
Since the amplification degree on the photoreceiver side must be increased, there is a problem in that the S/N ratio is poor and accurate measurements cannot be performed.

In view of the above, an object of the present invention is to provide a highly sensitive pulse wave detector that can be used in an electronic finger blood pressure monitor to realize highly accurate measurement.

(d) Means and operation for solving the problems The pulse wave detector of the present invention has a cylindrical inner wall of a cuff formed in a cylindrical shape.
A light emitting element and a light receiving element are provided close to each other, and light is projected from the light emitting element to the finger artery, and reflected light from the finger artery is received by the light receiving element.

In this pulse wave detector, the light emitting element, the light receiving element, and the finger artery are also close to each other, and the optical path is short.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 shows a pulse wave detector according to an embodiment of the present invention, FIG. 1(a) is a schematic side view thereof, and FIG. 1(b) is a schematic side view thereof.
It is a perspective view seen from the paper surface side.

This pulse wave detector has a cylindrical cuff 2 inside a cylindrical member 1.
is inserted. A light emitting element 3 and a light receiving element 4 are provided close to each other on the inner wall surface of the cuff 2.

At the time of pulse wave detection, the finger 5 is inserted into the cuff 2, and the cuff 2 is pressurized by a pressurizing pump (not shown), so that the finger 5 is compressed. Light is projected from the light emitting element 3 to the artery 6 of the finger 5, and the artery 6
The light is reflected by the light receiving element 4 and received by the light receiving element 4. Therefore, the light receiving element 4 detects a pulse wave signal that changes during the pressurization or depressurization process of the cuff 2. In this case, since the optical path from the light emitting element 3 to the artery 6 and from the artery 6 to the light receiving element 4 is short,
The detected pulse wave signal level is as shown in Fig. 5 ((
a): conventional, (b): present invention], significantly increased, and 10
Sensitivity is improved by more than double.

FIG. 2 is a partially cutaway perspective view of the top cover and front side of a finger electronic blood pressure monitor in which a pulse wave detector according to another embodiment of the present invention is used. In the figure, a battery section 12 including a power battery is located at the back right of the main body case 11, a pressure pump 13 is located at the front right, an air buffer 14 is located at the center, and an acupressure unit 15 is located at the left. It is provided. Also,
A board 16 is provided in the upper part, and a power switch key 17, a start switch key 18, and a display 19 are provided on this board 16. Also,
An electronic circuit section such as an MPU is mounted directly or indirectly on the lower surface of the board 16.

The acupressure link section 15 is composed of a cylindrical member 20 and a cuff 21 provided on the inner periphery of the cylindrical member 20. As shown in FIG. 3, this cuff 21 has a plurality of hollow trapezoidal convex portions 23a, 23b,...
..., 23h are formed, and the convex portion 23a
, 23b, . It is inserted in. Further, a recessed hole 25c is provided in the convex portion 23c of the cuff 21, and this recessed hole 2
5c is provided with a light emitting element 26, and further adjacent convex portion 2
3d is provided with a recessed hole 25d, and a light receiving element 27 is provided in this recessed hole 25d. Light emitting element 26 and light receiving element 2
7 are connected to the circuit section by lead wires 28 and 29, respectively. The light emitting element 26 and the light receiving element 27 are used to detect a pulse wave by projecting light from the light emitting element 26 onto the artery of the finger being compressed and receiving the reflected light at the light receiving element 27. In other words, a pulse wave sensor is used. It is provided as part of the

FIG. 4 is a block diagram of the digital finger sphygmomanometer according to the above embodiment. In the figure, the cuff 21 is provided with a light emitting element 26 and a light receiving element 27 for pulse wave detection, as described above.

The light emitting element 26 is driven by a command from an MPU (microprocessor unit) 33, and the output of the light receiving element 27 is sent to the MPU 33 via an amplifier 31 and an A/D converter 32.
It is now being incorporated into the

The cuff 21 is also connected to a pressure sensor 34, an air buffer 14, a slow exhaust valve 37, and a rapid exhaust valve 38, and the pressurizing pump 13 is connected to the force 21 via a non-return valve 36.

The cuff pressure detected by the pressure sensor 34 is amplified by an amplifier 35, and is taken into the MPU 33 via the A/D converter 32.

The MPU 33 has a built-in memory for storing programs and calculated values, and also has a function to import pulse wave data and cuff pressure data by switching from the A/D converter 32, and a function to turn the pressure pump 3 on.
N10F F function, quick exhaust valve 38 to 0N10F
It has a function to determine blood pressure from pulse wave data and cuff pressure data, a function to distinguish between measurement in progress and other states.

Further, the determined blood pressure values, that is, the systolic blood pressure (SYS) and the diastolic blood pressure (DIA) are output from the MPU 24 and displayed on the display 19, and a notification sound is output from the buzzer 39 according to a command from the MPU 33. It has become.

Also in the pulse wave detecting section of the electronic blood pressure monitor of this embodiment, the light projected from the light emitting element 26 is reflected by the artery of the finger and is received by the light receiving element 27.

(f) Effects of the Invention According to this invention, since a reflective type is adopted, the pulse wave detection sensitivity is improved, and if this pulse wave detector is used in an electronic finger blood pressure monitor, high precision blood pressure measurement can be achieved. It can be performed.

[Brief explanation of the drawing]

FIG. 1 shows a pulse wave detector according to an embodiment of the present invention.
FIG. 1(a) is a schematic side view thereof, FIG. 1(b) is a perspective view thereof, and FIG. 2 is a perspective view of an electronic finger blood pressure monitor in which a pulse wave detector according to another embodiment of the present invention is used. , FIG. 3 is a perspective view of the electronic blood pressure monitor for authorized persons before the cuff is inserted, FIG. 4 is a block diagram of the electronic blood pressure monitor for authorized persons, and FIG. 5 is a diagram showing the detected pulse waves of the conventional and the present invention. A waveform diagram for comparison, FIG. 6, is a diagram for explaining the principle of a conventional pulse wave detector. 2.21: Cuff, 3.26: Light emitting element, 4.27
: Light receiving element, 6: Finger artery. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) In a pulse wave detector that projects light onto a finger artery and detects a pulse wave signal from the received light output, a light-emitting element and a light-receiving element are placed close to each other on the inner wall of a cylindrical cuff. 1. A pulse wave detector comprising: a light emitting element, and a light receiving element receives light projected from a light emitting element and reflected by a finger artery.