JPH09113311A - Measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring instrument which can automatically adjust the offset of operational amplifiers without using any DC cutting filter. SOLUTION: The reference voltage values of operational amplifiers 551 and 561 are stored beforehand in the pulse wave data processing section 55 and body motion data processing section 56 of a portable plethysmograph and, at the time of determining the pulse frequency or pitch of a patient from the detected result of each sensor, the pulse wave data and body motion data of the patient are corrected so that the reference voltage values can become medium points.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for displaying a detection result of a pulse wave or body movement by a sensor. More specifically, the present invention relates to an offset correction technique when an analog signal output from a sensor is amplified by an operational amplifier.

[0002]

2. Description of the Related Art In a pulse meter or the like, a pulse wave is detected by a sensor provided therein, and an analog signal output from this sensor is first amplified by an operational amplifier and then A
The signal is converted into a digital signal by the / D converter, and thereafter, frequency analysis is performed by the microcomputer, and the pulse rate is obtained from the spectrum and displayed. In the measuring device such as the pulse rate meter, as long as the analog signal output from the sensor is amplified by the operational amplifier, the offset caused by the fluctuation of the reference voltage of the operational amplifier is, for example, as shown in FIG. Adjust trimmer or Figure 14
As shown in (b), it is necessary to insert a coupling capacitor CC after the operational amplifier to cut off the DC component. When frequency analysis is performed without correcting the offset, a high-level line spectrum appears at the position of frequency 0 Hz when frequency analysis is performed, and the line spectrum corresponding to the pulse wave appearing in the low frequency region can be specified. This is because there is a problem in data processing such as loss of data. That is, when obtaining the pulse rate from the frequency analysis result, first, in the obtained spectrum, a line spectrum with a large intensity is found, and this line spectrum appears and the pulse rate is obtained from the frequency. This is because, if a line spectrum with a large intensity due to is appeared, this spectrum may be confused with the line spectrum corresponding to the pulse wave. Also, when the pulse wave signal is reproduced from the frequency analysis result, its reproducibility is low.

[0003]

However, in the method of trimmer adjusting the offset correction as in the conventional pulse meter, it is necessary to make an adjustment each time the pulse rate is measured, which is troublesome. There is. Further, when the coupling capacitor is used as the DC cut filter, there is a problem that the output signal from the sensor is distorted by the time constant of the coupling capacitor instead of being able to automatically correct the offset.

[0004] In view of the above problems, the object of the present invention is to:
An object of the present invention is to provide a measuring device capable of automatically adjusting an offset in an operational amplifier without using a DC cut filter.

[0005]

In a measuring device according to the present invention, a sensor for detecting a state signal such as a pulse wave or body movement and a driving voltage from a power source section using a battery as a power source drive the sensor to output. To amplify the analog signal, an A / D converter that converts the amplified signal output from the operational amplifier into a digital signal, and a sensor detection based on the digital signal output from the A / D converter. A data processing means composed of a microcomputer for obtaining the result and a display means for displaying the detection result of the sensor obtained by the data processing means are provided, and the data processing means operates the operational amplifier before starting the measurement of the status signal. The reference voltage level storage means for storing the level of the reference voltage generated from the drive voltage. The value of to which voltage is characterized by being configured to determine a detection result of the sensor performs operation on the digital signal output from the A / D converter so that the middle point.

In the present invention, it is preferable that the reference voltage is input to the A / D conversion section, converted into a digital signal in the A / D conversion section, and then stored in the reference voltage level storage means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

(Overall Structure) FIG. 1 is an explanatory view showing the structure of a portable pulse wave measuring apparatus of this example.

In FIG. 1, a portable pulse wave measuring device 1 of this example is a device body 10 having a wristwatch structure, a cable 20 connected to the device body 10, and a cable 20.
And a pulse wave detection sensor unit 30 provided on the tip side of the. A connector piece 80 is formed on the tip end side of the cable 20, and the connector piece 80 is detachable from the connector section 70 formed on the 6 o'clock side of the apparatus body 10. The device main body 10 is provided with a wristband 12 that is wound around the arm from the 12 o'clock direction of the wristwatch and fixed at the 6 o'clock direction. The pulse wave detection sensor unit 30 is mounted between the base of the index finger and the finger joint while being shielded from light by the sensor fixing band 40. When the pulse wave detection sensor unit 30 is attached to the base of the finger in this way, the cable 20 can be short, so that the cable 20
Does not get in the way while running. Further, when the distribution of body temperature from the palm to the fingertip is measured, the temperature at the fingertip decreases significantly when it is cold, whereas the temperature at the base of the finger does not relatively decrease. Therefore, if the pulse wave detecting sensor unit 30 is attached to the base of the finger, the pulse rate and the like can be accurately measured even when running outdoors on a cold day.

(Structure of the Device Main Body) FIG. 2 is a plan view showing the device main body of the portable pulse wave measuring device of this embodiment with the wristband and cables removed, and FIG. 3 is the portable pulse wave measuring device. It is the side view which looked at the apparatus from the direction of 3 o'clock.

In FIG. 2, the apparatus main body 10 is provided with a resin watch case 11 (main body case), and the front surface side of the watch case 11 is used in addition to the current time and date, while running or walking. Liquid crystal display device 13 with EL backlight for displaying pulse wave information such as pitch and pulse rate
(Display device) is configured. The liquid crystal display device 13 includes a first segment display area 131 located on the upper left side of the display surface, a second segment display area 132 located on the upper right side, and a third segment display area 1 located on the lower right side.
33 and a dot display area 134 located on the lower left side are configured, and various information can be graphically displayed in the dot display area 134.

A body movement sensor 90 for obtaining the pitch is built in the watch case 11, and an acceleration sensor can be used as the body movement sensor 90. Further, inside the watch case 11, the body movement sensor 90
Pulse rate based on the pulse wave signal measured by the pulse wave detection sensor unit 30 in order to obtain the time change of the pitch based on the body movement signal measured by As well as seeking changes in
In order to display it on the liquid crystal display device 13, a control unit 5 that performs various controls and data processing is configured. Since the control unit 5 is also configured with a clock circuit, the liquid crystal display device 13 can be used for normal time, lap time, split time, etc.
Can be displayed.

Button switches 111 to 115 for performing external operations such as time adjustment and display mode switching are formed on the outer peripheral portion of the watch case 11. Also,
On the surface of the watch case, a large button switch 11
6, 117 are configured.

In the power supply section of the portable pulse wave measuring apparatus 1, a small button-shaped battery 59 built in the watch case 11 is provided.
The cable 20 supplies electric power from the battery 59 to the pulse wave detecting sensor unit 30, and the detection result of the pulse wave detecting sensor unit 30 is displayed in the watch case 1.
1 is input to the control unit 5. Here, the output voltage of the battery 59 is boosted and then supplied to each sensor and the control unit 5.

In the portable pulse wave measuring apparatus 1, it is necessary to increase the size of the apparatus main body 10 as the functions thereof are increased. The main body 10 is set to a wristwatch at 6 o'clock and 12
It cannot be expanded in the direction of time. Therefore, the device body 1
For 0, a horizontally long watch case 11 whose length dimension in the 3 o'clock and 9 o'clock directions is longer than the length dimension in the 6 o'clock and 12 o'clock directions is used. However, the wristband 12
Since the wristband 12 is connected at a position biased toward the 3 o'clock side, the wristband has a large overhanging portion 101 in the 9 o'clock direction, but such a large overhanging portion is in the 3 o'clock direction. There is no. Therefore, the horizontally long watch case 11
Instead of using the watch, the wrist can be bent freely, and the back of the hand does not hit the watch case 11 even if it falls.

A battery 59 is provided inside the watch case 11.
On the other hand, in the direction of 9 o'clock, the flat piezoelectric element 5 for the buzzer
8 are arranged. Since the battery 59 is heavier than the piezoelectric element 58, the position of the center of gravity of the apparatus main body 10 is in a position deviated in the 3 o'clock direction. Since the wrist band 12 is connected to the side where the center of gravity is deviated, the device body 10 can be stably attached to the arm. In addition, the battery 59 and the piezoelectric element 5
8 and 8 are arranged in the plane direction, the apparatus main body 10 can be made thin, and the user can easily replace the battery 59 by providing the battery lid 118 on the back surface part 119 as shown in FIG. .

(Structure of Mounting Device Main Body on Arm) In FIG. 3, in the 12 o'clock direction of the watch case 11, there is a connecting portion 105 for holding the stop shaft 121 attached to the end portion of the wristband 12. Has been formed. In the 6 o'clock direction of the watch case 11, the wristband 12 wound around the arm is folded back at an intermediate position in the length direction, and a receiving portion 106 to which a fastener 122 for holding this intermediate position is attached is formed. Has been done.

In the 6 o'clock direction of the apparatus main body 10, the portion from the back surface portion 119 to the receiving portion 106 is the watch case 1.
It is molded integrally with 1 and is about 115 ° to the back surface 119.
The rotation stopping portion 108 forms an angle. That is, when the device main body 10 is mounted by the wristband 12 so as to be positioned on the upper surface portion L1 (the back of the hand) of the right wrist L (arm), the back surface portion 119 of the watch case 11 is attached to the upper surface portion L1 of the wrist L. While the rotation stopper 108 is
It abuts on the side face L2 having the radius R. In this state, the back surface portion 119 of the apparatus body 10 feels to straddle the radius R and the ulna U, while the bending portion 109 between the rotation stopping portion 108 and the back surface portion 119 and the rotation stopping portion 108 contact the radius R. It makes you feel like you're in touch. As described above, since the rotation stopping portion 108 and the back surface portion 119 form an anatomically ideal angle of about 115 °, even if the device body 10 is rotated in the direction of arrow A or arrow B, The device body 10 has an arm L
Do not unnecessarily shift around. Further, since the back surface part 119 and the rotation stopping part 108 only restrict the rotation of the apparatus main body 10 at two positions on one side around the arm, the back surface part 119 and the rotation stopping part 108 can be surely secured even if the arm is thin. Since it comes into contact with, you can surely obtain the anti-rotation effect, but you do not feel cramped even if your arm is thick.

(Structure of Sensor Unit for Pulse Wave Detection) FIG. 4
FIG. 4 is a cross-sectional view of a pulse wave detection sensor unit of this example.

In FIG. 4, the pulse wave detection sensor unit 30 has a component housing space 300 formed therein by covering a back side of a sensor frame 36 as a case body with a back cover 302. The circuit board 35 is disposed inside the component storage space 300. On the circuit board 35, the LED 31, the phototransistor 32, and other electronic components are mounted. Pulse wave detection sensor unit 3
At 0, the end of the cable 20 is fixed by a bush 393, and each wiring of the cable 20 is soldered on the pattern of each circuit board 35. Here, the pulse wave detection sensor unit 30 is attached to the finger so that the cable 20 is pulled out from the base side of the finger to the apparatus main body 10 side. Therefore, the LED 31 and the phototransistor 32 are arranged along the length direction of the finger, of which the LED 31 is located on the tip side of the finger and the phototransistor 32 is located on the base of the finger. Such an arrangement has an effect that external light does not easily reach the phototransistor 32.

In the pulse wave detecting sensor unit 30, a light transmitting window is formed on the upper surface portion (substantially pulse wave signal detecting portion) of the sensor frame 36 by the light transmitting plate 34 made of a glass plate.
The LED 31 and the phototransistor 32 have a light emitting surface and a light receiving surface, respectively, with respect to the light transmitting plate 34.
It is aimed towards. Therefore, the outer surface 3 of the light transmitting plate 34
When the finger surface is brought into close contact with 41 (contact surface with the finger surface / sensor surface), the LED 31 emits light toward the finger surface side, and the phototransistor 32 causes the photo transistor 32 to emit light from the LED 31 toward the finger side. The light reflected from can be received. Here, the outer surface 341 of the translucent plate 34 has a structure protruding from the peripheral portion 361 for the purpose of enhancing the adhesiveness with the finger surface.

In this example, the LED 31 is made of InGaN.
System (indium-gallium-nitrogen system) blue LED is used, and its emission spectrum has an emission peak at 450 nm, and its emission wavelength range is from 350 nm to 60 nm.
It is in the range up to 0 nm. LE having such emission characteristics
Corresponding to D31, in this example, the phototransistor 3
2, a GaAsP-based (gallium-arsenic-phosphorus-based) phototransistor is used, and the light receiving wavelength region of the device itself has a main sensitivity region of 300 nm to 600 nm.
Up to 300 nm and there is a sensitivity region below 300 nm.

The pulse wave detecting sensor unit 30 thus constructed is attached to the base of the finger by the sensor fixing band 40. In this state, when the LED 31 emits light toward the finger, the light is emitted to the blood vessel. When hemoglobin arrives and hemoglobin in the blood absorbs a part of the light and reflects it. The light reflected from the finger (blood vessel) is the phototransistor 3
The light is received by 2, and the change in the amount of received light corresponds to the change in blood volume (pulse wave of blood). That is, when blood volume is high,
While the reflected light becomes weaker and the reflected light becomes stronger as the blood volume decreases, the pulse rate and the like can be measured by detecting the change in the reflected light intensity.

In this example, an LED 31 having an emission wavelength range of 350 nm to 600 nm and a phototransistor 32 having a reception wavelength range of 300 nm to 600 nm are used. The biological information is displayed based on the detection result in the wavelength region up to approximately 600 nm, that is, in the wavelength region of approximately 700 nm or less. By using the pulse wave detecting sensor unit 30, even when external light hits the exposed part of the finger, light having a wavelength region of 700 nm or less among the light included in the external light uses the finger as a light guide and the phototransistor 32 (received light). Part) is not reached. The reason is that light having a wavelength range of 700 nm or less included in external light tends not to easily pass through a finger. Therefore, even if external light is applied to a part of the finger not covered with the sensor fixing band 40, This is because it cannot reach the phototransistor 32 through the finger. In contrast,
When an LED having an emission peak near 880 nm and a silicon-based phototransistor are used, the light receiving wavelength range thereof extends from 350 nm to 1200 nm. In this case, since the pulse wave is detected based on the detection result of the light having a wavelength of 1 μm that can easily reach the light receiving portion by using the finger as a light guide, it is caused by the fluctuation of the external light. False positives are likely to occur.

Further, since the pulse wave information is obtained by using the light in the wavelength region of about 700 nm or less, the S / N ratio of the pulse wave signal based on the blood volume change is high. The reason for this is that hemoglobin in blood has an extinction coefficient for light with a wavelength of 300 nm to 700 nm at a wavelength of 8 which is conventional detection light.
Several times to about 100 times the absorption coefficient for 80 nm light
Because it is more than twice as large, it changes sensitively to blood volume changes,
It is considered that the detection rate (S / N ratio) of the pulse wave based on the blood volume change is high.

(Structure of Control Unit) As shown in FIG. 5, the control unit 5 includes a pulse wave data processing unit 5 for obtaining a pulse rate and the like based on an input result from the pulse wave detecting sensor unit 30.
5 and a pitch data processing unit 56 that obtains a pitch based on the input result from the body movement sensor 90. The pitch data processing unit 56 and the pulse wave data processing unit 55 are configured.
By outputting information such as pitch and pulse rate, the information can be displayed on the liquid crystal display device 13. Part of the pitch data processing unit 56 and the pulse wave data processing unit 55 is composed of a microcomputer that operates according to a stored program, and the function of this microcomputer is shown in a block diagram in FIG. There is.

First, in the pulse wave data processing unit 55, the analog signal input from the pulse wave detection sensor unit 30 is amplified by the operational amplifier 551 and then output to the A / D converter 553 via the sample hold circuit 552. It has become. Here, what is applied to the operational amplifier 551 is the drive voltage Vdd corresponding to the output voltage of the battery 59, and the operating midpoint (reference voltage) of the operational amplifier 551 is set to a voltage that is 1/2 the drive voltage Vdd. Has been done.

The pulse wave data storage unit 554 is composed of a RAM for storing pulse wave data converted into digital signals by the A / D converter 553. CP
In U51, pulse wave data stored in the pulse wave data storage unit 554 is subjected to fast Fourier transform (F
A frequency analysis unit 555 for performing (FT processing) is configured, and the frequency analysis unit 555 inputs the frequency analysis result to the pulse wave component extraction unit 556.
The pulse wave component extraction unit 556 extracts the pulse wave component from the input signal from the frequency analysis unit 555 and outputs the pulse wave component to the pulse rate calculation unit 557, and the pulse rate calculation unit 557 outputs the pulse wave according to the frequency component of the input pulse wave. The number is calculated, and the result is calculated by the liquid crystal display device 1.
3 is output.

(Structure of Pitch Calculation Unit) In the pitch data processing unit 55, after the analog signal input from the body motion sensor 90 is amplified by the operational amplifier 561, it is sent to the A / D converter 553 via the sample hold circuit 552. It is designed to output. The body movement data storage unit 564 is
It is composed of a RAM for storing body motion data converted into a digital signal by the A / D converter 553. In the CPU 50, the frequency analysis unit 555
The body movement data stored in the body movement data storage unit 564 is subjected to fast Fourier transform (FFT processing) as frequency analysis, and the frequency analysis result is input to the body movement component extraction unit 566. The body movement component extraction unit 566
The body motion component is extracted from the input signal from the frequency analysis unit 555 and output to the pitch calculation unit 567.
67 calculates the pitch from the frequency component of the input body movement, and outputs the result to the liquid crystal display device 13.

(Structure of Offset Correction Unit) In this example, the analog signals output from the pulse wave signal sensor unit 30 and the body motion sensor 90 are amplified by the operational amplifiers 551 and 561, but the operational amplifiers 551 and 561 use the battery 59. The reference voltage fluctuates due to fluctuations in the output voltage,
Since there is an offset, in order to correct the offset, the control unit 5 first sets a reference to the sample-hold circuit 552 by halving the drive voltage Vdd actually applied to the operational amplifiers 551 and 561. A correction reference signal input unit 502 for inputting a voltage as an offset correction reference signal (Vdd / 2) is configured. Also,
The reference voltage for offset correction is the sample hold circuit 5
52 and the A / D converter 553 through the CPU 51
Is input to the offset correction data storage unit 501 (reference voltage level storage means) and is stored as offset correction data. Here, the operational amplifier 5
Drive voltage Vdd actually applied to 51, 561 is 1/2
Offset correction data storage unit 501 of doubled reference voltage
Since the idling time is used every time the pulse rate and the pitch are measured, the output voltage of the battery 59 changes and the driving voltage Vdd applied to the operational amplifiers 551 and 561 changes. Also, the latest value is stored in the offset correction data storage unit 501. It should be noted that the driving voltage Vdd actually applied to the operational amplifiers 551 and 561 is stored in the offset correction data storage unit 501, and the value is calculated to obtain 1/1 of the driving voltage Vdd.
A voltage value corresponding to 2 may be obtained.

Further, the CPU 51 controls the pulse wave data storage unit 5
54, when calculating the pulse rate and the pitch (the detection result of the sensor) based on the data stored in the body movement data storage unit 564, the calculation is performed with the voltage obtained by multiplying the driving voltage Vdd by 1/2 as the middle point. Is configured to obtain the pulse rate and the pitch.

That is, in this example, the pulse wave data storage unit 5
54 to the data stored in the pulse wave data storage unit 554 and the body movement data storage unit 564 before the frequency analysis unit 555 performs the frequency analysis on the data stored in the body movement data storage unit 564. An offset correction unit 503 that performs correction based on the offset correction data stored in the offset correction data storage unit 50 is configured, and the offset correction unit 503 has the original waveform schematically shown in FIG. 6A. By comparing the corresponding data with the offset correction data stored in the offset correction data storage unit 50, the correction process with the reference voltage as the middle point is performed, and the correction process is schematically shown in FIG. The data corresponding to the signal having the corrected waveform shown in FIG.
5 is output. Therefore, the data output from the frequency analysis unit 555 includes the pulse wave signal and the body wave signal as shown in FIG. 7A showing the spectrum of the pulse wave signal and FIG. 7B showing the spectrum of the body motion signal. No line spectrum of 0 Hz appears in any of the motion signals.

Therefore, since a high level line spectrum does not appear at the position of frequency 0 Hz, it is possible to easily specify a line spectrum that appears in a low frequency region such as a pulse wave or body motion line spectrum, and perform frequency analysis. The reproducibility is high even when the original waveform is reproduced based on the data obtained.

(Operation of Portable Pulse Wave Measuring Device) The portable pulse wave measuring device 1 of the present embodiment has a clock mode, a stopwatch mode, a pulse rate measuring mode for measuring pulse wave information together with timing, and a pitch. Each mode of the portable pulse wave measuring apparatus 1 of the present example will be described since the mode can be switched to the mode for measuring.

FIG. 8 schematically shows each mode performed by the portable pulse wave measuring device 1 and the display contents on the liquid crystal display device 13 at that time.

In FIG. 8, step ST11 is the timepiece mode, in which the first segment display area 131 is set to 19
Monday, December 6, 1994 is displayed, and the second segment display area 132 displays that the current time is 10:08:59 pm. In the dot display area 134, "TIME" is displayed as the current mode is the clock mode. However, as will be described later, “TIME” is displayed in the dot display area 134 only for a few seconds immediately after the timepiece mode is selected. The third segment display area 13
Nothing is displayed in 3.

In the portable pulse wave measuring apparatus 1 of this example, when the button switch 111 located in the 2 o'clock direction is pressed in the timepiece mode, an alarm sound can be generated when, for example, one hour has elapsed. The time can be set arbitrarily. Also, the button switch 113 located at 11 o'clock
When is pressed, the EL backlight of the liquid crystal display device 13 is turned on for 3 seconds and then automatically turned off.

When the button switch 112 located in the 4 o'clock direction from this mode is pressed, the running mode (step S
T12). This mode is a mode when the portable pulse wave measuring device 1 is used as a stopwatch. In the running mode, the current time is displayed in the first segment display area 131 and the second segment display area 132 before the measurement is started (standby state).
Is displayed as "0: 00 ': 00: 00": 00 ". In the dot display area 134, "RUN" is displayed for 2 seconds as a guide indicating that the running mode is set, and then the graphic is switched.

When the button switch 112 in the 4 o'clock direction is pressed from this mode, the mode is switched to the lap time recall mode (step ST13). In this mode, the lap time and split time measured in the past using the portable pulse wave measuring device 1 are read out. In the lap time recall mode, the date is displayed in the first segment display area 131 and the current time is displayed in the second segment display area 132. In the dot display area 134, a message "LAP /
“RECALL” is displayed for 2 seconds, and then the latest pulse rate transition for each lap is displayed.

When the button switch 112 in the 4 o'clock direction is pressed from this mode, the mode is switched to the pulse wave measurement result recall mode (step ST14). This mode is used for portable pulse wave measuring device 1 when a marathon etc.
This is a mode for reading out the temporal change of the pulse rate measured and stored by using, and the temporal change of the pitch previously measured using the portable pulse wave measuring apparatus 1. In this recall mode, the date is displayed in the first segment display area 131 and the current time is displayed in the second segment display area 132. In the dot display area 134, “RE
"SULT / RECALL" is displayed for only 2 seconds, and then a graph showing the change over time of the average pulse rate is displayed.

When the button switch 112 in the 4 o'clock direction is pressed again from this mode, the mode returns to the timepiece mode (step ST11) as indicated by arrow P1. Further, in steps ST12 to ST14, even when there is no input for 10 minutes, the mode automatically returns to the timepiece mode (step ST11) as indicated by arrow P2. When returning to this clock mode, the first segment display area 1
The date is displayed in 31 and the second segment display area 13
The current time is displayed in 2.

In this example, when the timepiece mode is set, the dot display area 134 displays "TIME" indicating that the timepiece mode has been returned, as shown enlarged in FIG. 9A. As shown in FIG. 9B, the guidance display automatically disappears after 2 seconds, and the normal state of the clock mode (step S
T15). In the normal state of the timepiece mode, nothing is displayed in the dot display area 134. That is, power is saved by displaying a dot for the minimum time required to guide the user to the mode and displaying that it is not in the normal state of the watch mode. There is.

In the portable pulse wave measuring apparatus 1 of this example, when the connector piece 80 is attached to the connector portion 70 in any state, as shown by an arrow P3 in FIG. 8, the running mode (step ST12). Automatically switches to. The running mode at this time is a mode in which not only the stopwatch operates but also the pitch and pulse rate during running can be measured.

The function in the running mode as the pitch meter and the pulse rate meter will be described with reference to FIG.

First, in FIG. 10, when the mode is switched to the running mode for the pitch meter and the pulse rate meter (step ST31), as shown in FIG. 11 (a), the first segment display area 131 of the liquid crystal display device is currently displayed. The time is displayed, and “0: 0” is displayed in the second segment display area 132.
"0 ': 00": 00 "is displayed and the dot display area 13
4 displays “RUN”. In addition, the heart mark flashes in the third segment display area 133 to indicate that the mode has been switched to the running mode as the pitch meter and the pulse rate meter.

By switching the mode, power is supplied to the pulse wave data processing unit 55 and the like, and initialization processing such as setting of the operation cycle is performed. 2 seconds later,
The pulse wave signal is taken in to measure the initial pulse rate. At this time, in the dot display area 134, "ST
"OP / 5" is displayed (step ST32), and "MOT"
The display of "ION / 4" (step ST33) is 2 Hz.
Will be alternated and displayed for 5 seconds not to move. The number displayed at this time is a countdown for 5 seconds and is switched. Then, a standby state is entered until the button switch 117 located on the upper side of the surface of the apparatus main body 10 is pressed so as to start measuring time (step ST34).

By utilizing the time for such initialization processing, a voltage value corresponding to 1/2 of the driving voltage Vdd actually applied to the operational amplifiers 551 and 561 is stored in the offset correction data storage section 501. Done.

In this standby state, the original waveform of the pulse wave signal is graphically displayed in the dot display area 134, as shown in FIG. 11 (b). The original waveform displayed here is the latest data. Therefore, if the waveform and level of the original waveform of the pulse wave signal are confirmed before starting the time measurement (marathon), the LED 31 and the phototransistor 32
It is possible to determine in detail whether the mounting state of the device is good or bad. Further, by adjusting the LED 31 and the phototransistor 32 while checking the shape and level of the original waveform, the positions of the LED 31 and the phototransistor 32 can be set to the optimum positions. Moreover, it can be confirmed in advance whether or not the environment is such that the ambient temperature and humidity can be measured. Moreover, such a feature
When manufacturing the portable pulse wave measuring device 1, it can be used for inspection and the like. Further, since the original waveform is displayed graphically, it is possible to confirm whether or not the time axis has changed due to battery exhaustion or the like. In the third segment display area 132, the initial pulse rate “75” obtained from pulse conversion is displayed.

From this state, when the marathon is started and the button switch 117 located on the upper surface of the apparatus body 10 is pressed at the same time, the elapsed time is started and the pitch and pulse rate are also measured (step ST3).
5).

As shown in FIG. 12 (a), these measurement results show that the elapsed time is first displayed in the second segment display area 132, and the dot display area 134 graphically shows the temporal change of the pulse rate. Is displayed. The graphic display performed at this time is a bar graph extending from the bottom to the top. During this time, the third segment display area 13
In 3, the scale of the vertical axis of the graph displayed in the dot display area 134 and the pulse rate at that time are displayed.

In this state, the pulse rate is within the range (pulse rate 1
When entering the specified range from 20 to 168)
As shown in FIG. 2 (b), the pulse rate is graphically displayed as a difference with respect to a preset reference pulse rate (step ST36). The graphic display performed at this time is a bar graph in which a pulse rate of 150 is set at a substantially middle position on the vertical axis, and a portion corresponding to a difference from this value extends vertically (in the positive and negative directions). A mark indicating the designated range of the pulse rate is displayed at the right end of the dot display area 134.

During this time, the button switch 1 in the 8 o'clock direction
When 14 is pressed, a temporal change in pitch is graphically displayed in the dot display area 134 (step ST37).
The graphic display performed at this time is, as shown in FIG. 12C, a line graph in which the approximate middle position is the pitch 170. At this time, the third segment display area 13
In 3, the scale of the vertical axis of the graph displayed in the dot display area 134 (meaning that the approximate middle position of the vertical axis is the pitch 170) and the pitch at that time are displayed. in this way,
In the portable pulse wave measuring device 1 of this example, the dot display area 13
4, the time change of the pitch is displayed in a form different from the display of the pulse rate such as a line graph,
The runner can easily determine which information is displayed in the current display simply by looking at the display form.

From this state, when the button switch 114 in the 8 o'clock direction is pressed again, a state in which the temporal change of the pulse rate is displayed in the dot display area 134 (step ST3).
Return to 6).

When the button switch 116 located on the lower side of the surface of the apparatus body 10 is pressed while passing the predetermined passing point, the lap time at that time is displayed in the first segment display area 131 (step ST38). . And
After 10 seconds, the process automatically returns to step ST36.

After that, when the player arrives at the goal and presses the button switch 117 located on the upper surface of the apparatus body 10 at the same time, the measurement of the pulse rate, the pitch, and the time is stopped, and the dot display area 134 displays "COOLING / DOW
"N" is displayed (step ST39). When 2 minutes have passed from this state, a temporal change in the pulse rate after the goal is reached is graphically displayed as a pulse recovery characteristic in the dot display area 134 (step ST40).

As shown in FIG. 13 (a), the graphic display of the pulse recovery characteristic is first made into a bar graph display which extends from the bottom to the top while keeping the scale with the pulse rate of 150 at the substantially middle position on the vertical axis. Replace After that, FIG.
As shown in (b), the graphic display is switched to a bar graph extending from the lower side to the upper side. During this period, the scale of the vertical axis of the graph displayed in the dot display area 134 and the pulse rate at that time are displayed in the third segment display area 133.

From this state, when the button switch 114 at the 8 o'clock position is pressed, "PUL" is displayed in the dot display area 134.
After “SE / RESULT” is displayed for 1.5 seconds (step ST41), the dot display area 134 displays the temporal change of the pulse rate in the current marathon (step ST42). When the button switch 114 located in the 8 o'clock direction is pressed, the "PITCH" is displayed in the dot display area 134.
"/ RESULT" is displayed for 1.5 seconds (step ST43), and then the dot display area 134 displays the temporal change of the pitch in this marathon (step ST44). Furthermore, the button switch 1 at 8 o'clock
When you press 14, the dot display area 134 displays “COOLIN
"G / DOWN" is displayed for 1.5 seconds (step S
(T45), the process returns to the state (step ST40) in which the temporal change in the pulse rate after reaching the dot display area 134 is graphically displayed as the pulse recovery characteristic.

When the button switch 116 located below the surface of the apparatus body 10 is pressed after the goal is reached, a message "PROTECT / MEMO" is displayed in the dot display area 134 as to whether or not the result of this time should be stored. "Y" is displayed (step ST46), and when the button switch 117 located on the upper surface of the apparatus main body 10 is pressed and "YES" is answered, it is determined that the result is being stored in the dot display area 134, "MEMORY". Is displayed (step ST
47) After 2 seconds, it returns to the initial state (step ST31).

When the button switch 112 at the 4 o'clock position is pressed after the measurement as the pitch meter and the pulse rate meter is completed, the mode is switched to the lap time recall mode (step ST13) as shown in FIG. From this mode, when the button switch 112 in the 4 o'clock direction is pressed, the pulse wave measurement result recall mode (step ST1
Switch to 4). Also in this mode, the dot display area 134 can graphically display the temporal changes in the pitch and the pulse rate. When the button switch 112 in the 4 o'clock direction is pressed from this state, the mode returns to the timepiece mode (step ST11).

When returning to this mode, the date is displayed in the first segment display area 133 and the current time is displayed in the second segment display area 132. Further, in the dot display area 134, it is displayed that the time is returned to the clock mode,
Although a guidance display such as "IME" is displayed, this display automatically disappears after 2 seconds as shown by arrow P4, and the normal state of the clock mode (step ST15) is set.

(Main Effects of the Embodiment) As described above, in this embodiment, before the frequency analysis unit 555 performs the frequency analysis on the data stored in the pulse wave data storage unit 554 and the body motion data storage unit 564. For the data stored in the pulse wave data storage unit 554 and the body movement data storage unit 564, the offset correction unit 503 sets 1/2 of the drive voltage Vdd.
Correction processing is performed with a reference voltage corresponding to double the middle point, and then data processing such as frequency analysis is performed to obtain the pulse rate, pitch, and the like. Therefore, the operational amplifiers 551, 5
The reference voltage set to 61 and the operational amplifier 551,
Reference voltage actually applied to 561 (1 of drive voltage Vdd
/ 2 times the voltage), the correction process is performed with the reference voltage corresponding to 1/2 times the actual drive voltage Vdd as the middle point, so no DC cut filter is used. The offset can be adjusted automatically. Therefore, the line spectrum of 0 Hz does not appear in the spectrum after the frequency analysis. Therefore, when obtaining the pulse rate from the frequency analysis result, it is possible to easily identify the line spectrum corresponding to the pulse wave or body motion that appears in the low frequency region close to 0 Hz, and use the data after performing the frequency analysis. Therefore, the reproducibility is high even when reproducing the original waveform.

[0062]

As described above, in the sensor device according to the present invention, the level of the reference voltage of the operational amplifier is stored in advance, and the pulse wave signal or body detected by the sensor is stored based on the stored data. It is characterized in that the moving signal is subjected to correction processing so that the reference voltage becomes the midpoint, and the pulse rate, pitch, etc. are obtained from the corrected data. Therefore,
According to the present invention, the offset can be automatically adjusted in the operational amplifier without using the DC cut filter. Therefore, the spectrum after frequency analysis as data processing has 0
Since the line spectrum of Hz does not appear, it is possible to easily identify the line spectrum corresponding to the pulse wave and body motion that appear in the low frequency region, and even when the original waveform is reproduced from the data after data processing, Highly reproducible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration and a usage state of a portable pulse wave measuring device according to an embodiment of the present invention.

FIG. 2 is a plan view of a device body of the portable pulse wave measuring device shown in FIG.

FIG. 3 is an explanatory view of the main body of the portable pulse wave measuring device shown in FIG. 1 when viewed from the direction of the wristwatch at 3 o'clock.

4 is a cross-sectional view of a pulse wave detection sensor unit used in the portable pulse wave measurement device shown in FIG.

5 is a block diagram showing a part of the functions of a control unit (pulse wave data processing unit and pitch data processing unit) of the portable pulse wave measuring device shown in FIG.

6A is an explanatory diagram schematically showing a signal waveform of the operational amplifier before offset correction in the control unit shown in FIG. 5, and FIG. 6B schematically shows a waveform of the operational amplifier after offset correction. FIG.

FIG. 7A is an explanatory diagram showing a spectrum when frequency analysis is performed on the pulse wave data after the offset correction of the operational amplifier, and FIG. 7B is a frequency analysis of the body movement data after the offset correction of the operational amplifier. It is explanatory drawing which shows the spectrum when it performs.

FIG. 8 is an explanatory diagram showing each mode of the portable pulse wave measuring device shown in FIG. 1.

9A is an explanatory diagram showing a guidance display when the clock mode is selected from the modes shown in FIG. 8, and FIG.
It is explanatory drawing which shows the state which this guidance display disappeared.

10 is an explanatory diagram for explaining a function in a running mode as a pitch meter and a pulse rate meter in the portable pulse wave measuring device shown in FIG. 1. FIG.

11 (a) is an explanatory view showing the contents of the display indicating that the mode has been switched to the running mode as the pitch meter and the pulse rate meter shown in FIG. 10, and FIG. 11 (b) is a display before starting measurement in this mode. It is explanatory drawing which shows the content of.

FIG. 12A is an explanatory view showing a display form before the pulse rate reaches within a predetermined range after the measurement of the pulse rate is started in the running mode as the pitch meter and the pulse rate meter shown in FIG. 11. FIG. 1B is an explanatory view showing a display form after the pulse rate reaches a predetermined range, and FIG.
FIG. 7 is an explanatory diagram showing a display form when showing a temporal change in pitch.

13A is a display when the pulse rate is within a predetermined range after the operation to stop the measurement of the pulse rate in the portable pulse wave measuring device shown in FIG. FIG. 3B is an explanatory diagram showing a form, and FIG. 6B is an explanatory diagram showing a display form when the pulse rate is out of a predetermined range.

FIG. 14A is an explanatory diagram showing a correction method for an offset of an operational amplifier in a conventional pitch meter, and FIG.
FIG. 9 is an explanatory diagram showing a correction method for an offset of an operational amplifier in another conventional pitch meter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Portable pulse wave measuring device (measuring device) 5 ... Control part 10 ... Device main body 12 ... Wristband 13 ... Liquid crystal display device 30 ... Pulse wave detection sensor unit 31・ ・ ・ LED 32 ・ ・ ・ Phototransistor 55 ・ ・ ・ Pulse wave data processing unit 56 ・ ・ ・ Pitch data processing unit 90 ・ ・ ・ Body motion sensor 501 ・ ・ ・ Offset correction data storage unit (reference voltage level storage means) ) 502 ... Correction reference signal input section 503 ... Offset correction section 551, 561 ... Operational amplifier 552 ... Sample hold circuit 553 ... A / D converter 554 ... Pulse wave data storage section 555 ... Frequency analysis unit 556 ... Pulse wave component extraction unit 557 ... Pulse rate calculation unit 564 ... Body movement data storage unit 566 ... Body movement component extraction unit 567 ... Pitch computing unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Chiaki Nakamura 1-8-1, Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Electronic Industry Co., Ltd.

Claims (2)

[Claims] 1. A sensor for detecting a status signal such as a pulse wave and a body movement, an operational amplifier driven by a drive voltage from a power supply unit using a battery as a power source, and amplifying an analog signal output from the sensor, and the operational amplifier. An A / D conversion unit for converting the amplified signal output from the A into a digital signal;
A data processing unit composed of a microcomputer that obtains the detection result of the sensor based on the digital signal output from the / D conversion unit; and a display unit that displays the detection result of the sensor obtained by the data processing unit. The data processing means comprises a reference voltage level storage means for storing the level of the reference voltage generated from the drive voltage applied to the operational amplifier before starting the measurement of the state signal, It is configured to calculate the digital signal output from the A / D conversion unit so as to obtain the detection result of the sensor so that the value of the voltage stored in the level storage unit becomes the midpoint. Characteristic measuring device. 2. The reference voltage according to claim 1, wherein the reference voltage is input to the A / D conversion unit, converted into a digital signal in the A / D conversion unit, and then stored in the reference voltage level storage unit. A measuring device characterized in that