JPS63145630A - Sphygmograph - 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 Field of Industrial Application The present invention relates to a pulse wave meter used as a general household or medical device.

2. Description of the Related Art Conventionally, a pulse wave meter has been known as a medical measuring instrument for observing or measuring the state of blood circulation in the human body. Among these, using a fingertip plethysmometer that non-invasively measures increases and decreases in peripheral blood flow, it is possible to easily observe and measure the quality of blood circulation function.

Problems to be Solved by the Invention However, in the conventional pulse wave meter, as shown in FIG.
On the other hand, the AC component C is about several tens of mV to several hundred m
It is as small as V. Therefore, it is extremely difficult to extract only the alternating current component from the pulse wave signal a. Moreover, depending on the person being measured, the voltage value of the DC component varies by several volts, and the voltage value of the AC component varies by about -200 times.

Therefore, in order to adjust the detected pulse wave waveform to a certain constant voltage value, the DC component is first removed using a bridge circuit or the like, and the AC component is extracted by changing the adjustment value of the regulator.

These tasks were performed manually each time the person to be measured changed, and judgments were made while looking at the output waveform. The present invention improves the reproducibility of measurements by automatically adjusting and outputting the output voltage of the pulse waveform to a certain constant value.

The present invention provides a pulse wave meter with improved reliability.

Means for Solving the Problems In order to solve the above problems, the pulse wave meter of the present invention includes a light-emitting element, irradiates the living body with light emitted from the light-emitting element, and emits the reflected light or light reflected by the living body. a light-receiving element that receives transmitted light that has passed through a living body, a reference device that generates a reference DC voltage, and an amplifier that extracts a pulse wave signal from the biological signal obtained from the light-receiving element and the reference DC voltage emitted from the reference device. , a comparator that compares the voltage value of the pulse wave signal output from this amplifier with a certain predetermined voltage value, and a comparator that adjusts the value of the reference DC voltage and then switches to output the pulse wave waveform. It has a signal changeover switch.

Function Input the reference DC voltage to the input section of the amplifier as described above,
A light receiving element is connected to the feed bank section formed by the other input section and the output section, and the value of the reference DC voltage is adjusted using a comparator so that the voltage value of the output signal becomes a certain predetermined value.
After that, the pulse wave waveform is output by switching the signal changeover switch, so the input pulse wave waveform is automatically adjusted so that the output voltage becomes a certain constant value before being output. be.

EXAMPLE Hereinafter, an example of the pulse wave meter of the present invention will be described with reference to the drawings.

In the figure, 1 is a light-emitting element such as a tungsten lamp that is turned on by a power source, and 2 is a CdS which irradiates a living body with the light emitted from this light-emitting element 1 and receives the light reflected by the living body or the transmitted light that has passed through the living body. 3 is a reference device that generates a reference DC voltage; 4 is a light-receiving element consisting of
6 is an amplifier that extracts a pulse wave signal from the biological signal obtained from the light-receiving element 2 and the reference DC voltage emitted from the reference device 3; A comparator 6 for comparing the values is a signal changeover switch, which is switched after the value of the reference DC voltage is adjusted by the comparator 6, and outputs a pulse wave waveform.

In the above configuration, when a fingertip is inserted between the light emitting element 1 and the light receiving element 2, light emitted from the light emitting element 1 passes through the fingertip and reaches the light receiving element 2. At this time, since the blood within the fingertip absorbs light, the amount of light reaching the light receiving element 2 changes depending on the increase or decrease in the amount of blood within the fingertip. It is medically clear that the amount of blood in the fingertips changes depending on the operating state of the heart and the elasticity of blood vessels in various parts of the body, and it is possible to know the state of health based on the increase or decrease in this blood amount. The light-receiving element 2 responds to the amount of change in light that indicates an increase or decrease in blood volume.
The resistance value changes as shown in Figure 2.

At this time, the resistance value of the reference device 3 connected to the input side of the amplifier 40 (Fig. 2 a) and the resistance value of the light receiving element 2 (Fig. 2 b)
) determines the amplification factor of the amplifier 4. The signal output in response to this change in amplification factor is the alternating current component of the pulse waveform shown in FIG. 2C. However, the alternating current component of the pulse waveform taken from a living body varies by about 2
A variation of about 200 times occurs in the pulse wave waveform output from the high-temperature generator 4 as well.

Therefore, as shown in FIG. 3, the value of the output voltage from the amplifier 4 is compared with predetermined values (upper and lower limit values) in a comparator 6. Based on the result, the reference voltage value output from the reference device 3 is changed by a certain amount. and,
Until the pulse wave output voltage value from the amplifier 4 falls within a predetermined value,
The comparator 6 adjusts the output voltage value of the reference device 3, and the amplifier 4
(Figure 3 a, b). Thereafter, the adjusted pulse waveform is output to the next stage processing circuit by a signal changeover switch S (switching from the a contact to the b contact).

Effects of the Invention As is clear from the above embodiments, the pulse wave meter of the present invention uses a reference device, a comparator, and an amplifier to increase the output voltage of a pulse wave waveform that contains a large amount of information indicating the health condition of the human body. By automatically adjusting and outputting the value to a certain constant value, it improves the reproducibility and reliability of the measurement, and also makes the measurement simple.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the pulse wave meter of the present invention, and FIG.
Figure a %C is a waveform diagram of the pulse waveform, Figure 3a. 4b is an adjustment waveform diagram of a pulse wave waveform, and FIGS. 4A to 4C are waveform diagrams of a conventional pulse wave meter. 1... Light emitting element, 2... Light receiving element, 3
...Reference device, 4...Amplifier, 6...
... Comparator, 6... Signal selection switch. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure f.

Claims (1)

[Claims] a light-emitting element, a light-receiving element that irradiates a living body with light emitted from the light-emitting element and receives reflected light reflected by the living body or transmitted light that has passed through the living body, a reference device that generates a reference DC voltage, and the light-receiving element an amplifier that extracts a pulse wave signal from the biological signal obtained from the reference device and a reference DC voltage emitted from the reference device; a comparator that compares the voltage value of the pulse wave signal output from the amplifier with a predetermined voltage value; A pulse wave meter comprising a signal changeover switch that outputs a pulse wave waveform after adjusting the value of the reference DC voltage using the comparator.