JP2003070750A - Temperature compensator for ear thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature compensator for an ear thermometer which compensates a reference temperature of a thermopile based on the difference of characteristics between the thermopile and a thermistor to detect correct body temperature. SOLUTION: Because temperature variation of an infrared detecting means 100 is calculated by a temperature variation calculating means 160 from temperature variation of a temperature detecting means 110 caused by the difference of thermal characteristics between the infrared detecting means 100 and the temperature detecting means 110 and, based thereon, a reference temperature calculated by a reference temperature calculating means 120 can be compensated by a reference temperature compensating means 170, a correct reference temperature of the infrared detecting means can be obtained. Accordingly correct ear temperature can be calculated by an ear temperature calculating means by the reference temperature and the relative temperature calculated by a relative temperature calculating means 130.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ear thermometer for detecting a body temperature of a living body by infrared rays emitted from an ear canal, and relates to a temperature correction device for an ear thermometer which appropriately corrects a temperature detected by an infrared sensor.

[0002]

2. Description of the Related Art An ear thermometer disclosed in Japanese Patent Laid-Open No. 2000-14648 is composed of an infrared sensor for detecting the intensity of infrared rays generated in the ear, a temperature sensor for detecting environmental temperature, a control means, and the like. . In this configuration, when the measurement switch is pressed, the detection signals from the infrared sensor and the temperature sensor are fetched and the ear temperature Tj is obtained.

The ear thermometer disclosed in Japanese Patent Laid-Open No. 2000-14649 has a first infrared sensor for detecting the intensity of infrared rays generated in the ear and the intensity of infrared rays emitted from the surface of the ear canal into the ear. The second infrared sensor for detecting the temperature, the temperature sensor for detecting the environmental temperature, the control means, and the like. In this configuration, when the measurement switch is pressed, the detection signals from the first and second infrared sensors and the temperature sensor are taken in, and the in-ear temperature measurement value (in-ear temperature) Tj and the ear hole surface temperature measurement value (ear hole surface) are detected. Temperature) Th, and the temperature difference (addition amount) U between the eardrum temperature (eardrum temperature) Tk and the ear temperature Tj is calculated based on the difference (Tj-Th) between these temperatures and the ear canal surface temperature Th. As a result, the eardrum temperature Tk is obtained by Tk = Tj + U.

In the above two references, the in-ear temperature Tj is corrected to the in-ear temperature Tjref corresponding to when the environmental temperature Ta is the reference temperature Tref, based on the environmental temperature Ta detected by the temperature sensor. It is disclosed that the correction amount ΔM is obtained.

Further, Japanese Patent Publication 2001-149324
The ear thermometer disclosed in No. 1 is a probe that is inserted into the ear canal of a human body, an infrared sensor that detects infrared rays emitted from the vicinity of the eardrum through this probe, and an operation that converts the output value into a body temperature value. It has a means and a display means for displaying the calculation result, and is provided with a temperature correction means for detecting the temperature of the probe tip and correcting the output value of the infrared sensor.

[0006]

However, the infrared sensor is usually composed of a thermopile element (hereinafter referred to as a thermopile) which converts Joule heat obtained by passing through an infrared permeable film into a voltage by a plurality of thermocouples, and its principle. Since only the upper relative temperature can be measured, a thermistor is provided in the vicinity of the thermopile, the temperature in the vicinity of the thermopile is measured, and it is known to perform zero point compensation of the thermopile using this temperature as a reference of relative temperature. There is a problem that the zero compensation is ambiguous and accurate temperature detection cannot be performed.

As shown in FIG. 4, when the thermopile temperature is 10 ° C. {THP (10)} and when it is 42 ° C. {THP (42)}, the output value of the thermopile is significantly different. For example, if the body temperature is 38 ° C, THP
In (10), Tthp3 (+ side) is output, but TH
It is known that Tthp6 (-side) is output at P (42), and the output values of both are significantly different. Therefore, if the reference temperature shifts a little,
Since the output values are completely different, accurate temperature detection cannot be performed, and the measured temperature changes every time measurement is performed.

Therefore, as in the above-mentioned reference, it has been proposed to correct this by correcting the output value from the thermopile in consideration of the environmental temperature. Attention is paid to the fact that there is a difference between the temperature rise Tthp of the thermopile and the temperature rise Tthm of the thermistor that occur after the ear thermometer is inserted into the ear, and the temperature rise due to the difference in temperature rise (T1-T2). It has been found that there are variations in detection. Further, it has been clarified that the above-mentioned difference in temperature rise is caused by a difference in thermal characteristics such as heat capacity and thermal conductivity between the thermistor and the thermopile.

Therefore, the present invention provides a temperature compensating device for an ear thermometer which corrects the reference temperature of the thermopile based on the difference in the thermal characteristics of the thermopile and the thermistor and enables accurate body temperature detection. is there.

[0010]

As shown in FIG. 1, the present invention provides an infrared detecting means 100 for detecting infrared rays emitted from the inside of an ear, and a temperature detecting means 110 for detecting the temperature around the infrared detecting means 100. A reference temperature calculation means 120 for calculating the reference temperature of the infrared detection means 100 based on the detection result of the temperature detection means 110; and a relative temperature calculation means 130 for calculating a relative temperature from the detection result of the infrared detection means 100. And at least an in-ear temperature calculating means 140 for calculating the in-ear temperature from the reference temperature and the relative temperature, and a temperature display means 150 for displaying the in-ear temperature calculated by the in-ear temperature calculating means 140 as body temperature. In the ear thermometer provided, a temperature for calculating the temperature change amount of the infrared detecting means 100 based on the detection result of the temperature detecting means 110. A reference temperature correction unit 170 that corrects the reference temperature calculated by the reference temperature calculation unit 120 based on the temperature change amount of the infrared detection unit 100 calculated by the temperature change amount calculation unit 160. And to have.

Therefore, according to the present invention, the temperature change amount of the infrared detecting means 100 is calculated from the temperature change amount of the temperature detecting means 110 due to the difference in thermal characteristics between the infrared detecting means 100 and the temperature detecting means 110. The calculation is performed by the calculation means 160, and based on this, the reference temperature calculation means 120
The reference temperature calculated by
Infrared detecting means 1 because it can be corrected by
An accurate reference temperature of 00 can be obtained, and thus the internal ear temperature calculation means 140 can calculate an accurate internal ear temperature based on the reference temperature and the relative temperature calculated by the relative temperature calculation means 130. It is a thing.

The temperature change amount calculating means calculates a temperature change amount of the temperature detecting means based on a detection result of the temperature detecting means, and a first temperature change amount calculating means. A second amount of temperature change of the infrared detecting means is calculated based on the amount of temperature change of the temperature detecting means calculated by the calculating means and the difference in thermal characteristics between the infrared detecting means and the temperature detecting means. It is desirable to be configured by a temperature change amount calculation means.

Furthermore, it is desirable that the thermal characteristics are heat capacity and thermal conductivity.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the ear thermometer 1 is provided with a probe 2 mounted in the ear, a thermopile 3 arranged at the proximal end portion of the probe 2, and a thermopile 3 in the vicinity thereof. The thermopile 3 includes at least a thermistor 4 for detecting a temperature close to the temperature at one end (reference temperature) and a control circuit 5 described below, and detects infrared rays emitted from the ear, specifically, the eardrum 18, to detect the body temperature. Is measured and displayed.

The control circuit 5 is provided in the main body of the ear thermometer 1, and includes an amplifier (A) 6 for amplifying the signal from the thermopile 3 and a digital value for the signal amplified by the amplifier 6. A / D converter to convert to (A / D)
7.Amplifier (A) that amplifies the signal from the thermistor 4
8, a reference voltage circuit (RV) 9 for supplying a reference voltage to the amplifier 8, a power supply circuit (BC) 10 for supplying power to the reference voltage circuit 9 and a microprocessor unit (MPU) 13 described below, and the power supply circuit 10 (B) 11 serving as a power source for the MPU 13, an MPU 13 including at least a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output port (I / O), etc., which is not shown. An electrically erasable / writable ROM (EEPROM) 15, a switch circuit (SWITCH) 14 having an operation switch, a display circuit (DISPLAY) 16 for displaying a temperature, a modem, and a transmission terminal connectable to a portable terminal mounted on the At least the communication circuit 17 and the like included therein.

The control circuit 5 having the above-mentioned configuration is, for example, an EEP.
The signal is processed according to the program written in the ROM 15. Hereinafter, a control routine of an example of the processing will be described with reference to the flowchart shown in FIG.

When a switch (not shown) connected to the switch circuit 14 is turned on, the control routine starts from step 200, and power is supplied from the power supply circuit 10 to each part in step 210. And first, step 220
At, the output THM (t0) of the thermistor 4 is read. Further, in step 230, the output THP from the thermopile 3 is read. Also, step 24
At 0, the output THM (t1) of the thermistor 4 is read at the same time as or immediately after the reading of the thermopile 3 (after t1 hours).

Then, at step 250, the temperatures T (thm) (t0) and T corresponding to the outputs THM (t0) and THM (t1) of the thermistor are output.
(Thm) (t1) is calculated, and in step 260, the temperature change rate ΔT (thm) of the thermistor is calculated based on the calculation result of step 250. As an example, for example,
Formula [ΔT (thm) = {T (thm) (t1) −T
(Thm) (t0)} / (t1-t0)].

Then, in step 270, the temperature change rate ΔT of the thermistor 4 calculated in step 260 is calculated.
Based on (thm), the reference temperature Tzero of the thermopile 3 is calculated. As an example, the temperature change rate ΔT (th) of the thermopile 3 is based on the temperature change rate ΔT (thm) of the thermistor 4 and the heat capacity difference (ΔHcap) of the thermistor 4 and the thermopile 3.
p) is, for example, the mathematical expression [ΔT (thp) = A · F (ΔTt
hm, ΔHcap) + K1], and the temperature change rate ΔT (thp) of the thermopile 3 and the reading time tr of the output THP by the thermopile 3 are used to calculate the reference temperature Tzero, for example, by the formula [Tzero = B · ΔT
(Thp) · t2 + K2]. In the above formula, A and B are operation constants, K1,
K2 is a correction term.

Then, in step 280, the relative temperature T (thp) is calculated from the output THP of the thermopile 3, and in step 290, the reference temperature Tzero.
And relative temperature T (thp) to ear temperature (body temperature) T (t
ag) is calculated, and the display circuit 16 is calculated in step 300.
The temperature is displayed as the body temperature via the, the power is turned off in step 310, and the control is ended in step 320.

According to the above control routine, the reference temperature Tzero of the thermopile 3 is conventionally calculated simply based on the output THM (t0) or THM (t1) of the thermistor 4, so that the thermopile at the time of reading the output of the thermopile 3 is read. 3 and the temperature of the thermopile 3 when the output THM (t0) of the thermistor 4 is read or the temperature of the thermopile 3 when the output THM (t1) of the thermistor 4 is read. Since it can be corrected, it is possible to obtain an accurate reference temperature of the thermopile temperature, and as a result, it is possible to accurately detect the body temperature.

[0023]

As described above, according to the present invention, the temperature rise of the thermistor, which rises when the probe of the ear thermometer is attached to the ear, based on the difference in the heat capacity and the thermal conductivity of the thermistor, Since the error in the temperature rise of the thermopile can be corrected, the body temperature can be accurately detected with a simple configuration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the invention.

FIG. 2 is a schematic configuration diagram of a control device for an ear thermometer according to an embodiment of the present invention.

FIG. 3 is a control flowchart diagram executed in the control device.

FIG. 4 is a characteristic diagram showing a relationship between temperature and thermopile output.

FIG. 5 is a characteristic diagram showing the relationship between time and temperature rise of the thermistor and thermopile.

[Explanation of symbols]

1 ear thermometer 2 probes 3 Thermopile 4 thermistor 5 control circuit 18 eardrum

Claims (5)

[Claims] 1. An infrared detecting means for detecting infrared rays emitted from the ear, a temperature detecting means for detecting a temperature around the infrared detecting means, and a reference of the infrared detecting means based on a detection result of the temperature detecting means. Reference temperature calculation means for calculating the temperature, relative temperature calculation means for calculating the relative temperature from the detection result of the infrared detection means, in-ear temperature calculation means for calculating the in-ear temperature from the reference temperature and the relative temperature, In an ear thermometer comprising at least a temperature display unit for displaying the in-ear temperature calculated by the in-ear temperature calculation unit as a body temperature, based on a detection result of the temperature detection unit, a temperature change amount of the infrared detection unit. And a reference temperature calculation means based on the temperature change amount of the infrared detection means calculated by the temperature change amount calculation means. Temperature correction device ear thermometer which is characterized by comprising a reference temperature correction means for correcting the calculated reference temperature Te. 2. The temperature change amount calculation unit calculates a temperature change amount of the temperature detection unit from a detection result of the temperature detection unit, and a first temperature change amount calculation unit. A second amount of temperature change of the infrared detecting means is calculated based on the amount of temperature change of the temperature detecting means calculated by the calculating means and the difference in thermal characteristics between the infrared detecting means and the temperature detecting means. The temperature correction device for an ear-type clinical thermometer according to claim 1, wherein the temperature correction amount calculation means is included. 3. The temperature correction device for an ear thermometer according to claim 1, wherein the thermal characteristic is a heat capacity. 4. The temperature correction device for an ear thermometer according to claim 1, wherein the thermal characteristic is thermal conductivity. 5. The temperature correction device for an ear thermometer according to claim 1, wherein the thermal characteristics are heat capacity and thermal conductivity.