JP4771193B2 - Ear thermometer temperature correction device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an ear thermometer that corrects the temperature detected by an infrared sensor in an ear thermometer that detects the temperature of a living body using infrared rays emitted from the inside of the ear canal.
[0002]
[Prior art]
The ear thermometer disclosed in Japanese Patent Publication No. 2000-14648 includes an infrared sensor that detects the intensity of infrared rays generated from within the ear, a temperature sensor that detects environmental temperature, a control unit, and the like. In this configuration, when the measurement switch is pressed, detection signals from the infrared sensor and the temperature sensor are taken in and the in-ear temperature Tj is obtained.
[0003]
In addition, the ear thermometer disclosed in Japanese Patent Publication No. 2000-14649 detects a first infrared sensor that detects the intensity of infrared rays generated from within the ear, and detects the intensity of infrared rays emitted from the ear hole surface into the ear. A second infrared sensor, a temperature sensor for detecting environmental temperature, a control means, and the like are included. 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, the temperature measurement value in the ear (intra-ear temperature) Tj, and the temperature measurement value in the ear canal surface (the ear hole surface). Temperature) Th is obtained, and the temperature difference (addition amount) U between the eardrum temperature (tympanic temperature) Tk and the ear temperature Tj is obtained based on the difference between these temperatures (Tj−Th) and the ear canal surface temperature Th. Accordingly, the eardrum temperature Tk is obtained by Tk = Tj + U.
[0004]
In the above two references, the correction amount ΔM for correcting the in-ear temperature Tj to the in-ear temperature Tjref corresponding to the reference temperature Tref based on the environment temperature Ta detected by the temperature sensor. Is disclosed.
[0005]
Further, an ear thermometer disclosed in Japanese Patent Publication No. 2001-149324 includes a probe inserted into the ear canal portion of a human body, an infrared sensor for detecting infrared rays emitted from the vicinity of the eardrum via the probe, and an output value thereof. Is provided with temperature correcting means for detecting the temperature of the probe tip and correcting the output value of the infrared sensor.
[0006]
[Problems to be solved by the invention]
However, an infrared sensor is usually composed of a thermopile element (hereinafter, thermopile) that converts Joule heat obtained by passing through an infrared transmission film into a voltage by a plurality of thermocouples, and can measure only the relative temperature in principle. It is known to provide a thermistor near the thermopile, measure the temperature near the thermopile, and perform zero compensation of the thermopile using this temperature as a reference for the relative temperature, but conventionally, this zero compensation is ambiguous and accurate. There is a problem that temperature cannot be detected.
[0007]
As shown in FIG. 4, the thermopile output value differs greatly between {THP (10)} when the thermopile temperature is 10 ° C. and {THP (42)} when the thermopile temperature is 42 ° C. For example, when the body temperature is 38 ° C., Tthp3 (+ side) is output in THP (10), but Tthp6 (− side) is output in THP (42), and both output values are large. It is known that it will be different. For this reason, if the reference temperature is slightly deviated, the output value is completely different, so that accurate temperature detection cannot be performed, and there is a problem that the measured temperature is different every time measurement is performed.
[0008]
Therefore, as described above, it has been proposed to improve this by correcting the output value from the thermopile in consideration of the environmental temperature, but the present inventor, as shown in FIG. Paying attention to the difference between the thermopile temperature rise Tthp and the thermistor temperature rise Tthm that occurs after inserting the thermometer into the ear, the temperature detection varies due to this temperature rise difference (T1-T2) Has been found to occur. Further, it has been clarified that the above-described difference in temperature increase is caused by a difference in thermal characteristics such as heat capacity and thermal conductivity between the thermistor and the thermopile.
[0009]
Therefore, an object of the present invention is to provide a temperature correction device for an ear thermometer that corrects the reference temperature of the thermopile based on the difference in thermal characteristics between the thermopile and the thermistor and enables accurate temperature detection.
[0010]
[Means for Solving the Problems]
As shown in FIG. 1, the present invention includes an infrared detection means 100 for detecting infrared rays emitted from the ear, a temperature detection means 110 for detecting the temperature around the infrared detection means 100, and detection by the temperature detection means 110. A reference temperature calculation unit 120 that calculates a reference temperature of the infrared detection unit 100 based on a result, a relative temperature calculation unit 130 that calculates a relative temperature from the detection result of the infrared detection unit 100, the reference temperature and the relative temperature In the ear-type thermometer comprising at least an in-ear temperature calculating means 140 for calculating an in-ear temperature from the ear, and a temperature display means 150 for displaying the in-ear temperature calculated by the in-ear temperature calculating means 140 as a body temperature. A temperature change amount calculating means 160 for calculating a temperature change amount of the infrared detecting means 100 based on a detection result of the detecting means 110; The computed by degrees change amount calculation unit 160 based on the temperature variation of the infrared detector 100 is to comprise a reference temperature correction means 170 for correcting the calculated reference temperature by the reference temperature calculation means 120.
[0011]
Therefore, according to the present invention, the temperature change amount of the infrared detection means 100 is calculated from the temperature change amount of the temperature detection means 110 due to the difference in thermal characteristics between the infrared detection means 100 and the temperature detection means 110. , And based on this, the reference temperature calculated by the reference temperature calculation means 120 can be corrected by the reference temperature correction means 170, so that an accurate reference temperature of the infrared detection means 100 can be obtained, thereby The ear temperature calculation means 140 can calculate an accurate ear temperature based on the reference temperature and the relative temperature calculated by the relative temperature calculation means 130.
[0012]
Further, the temperature change amount calculation means includes a first temperature change amount calculation means for calculating a temperature change amount of the temperature detection means from the detection result of the temperature detection means, and the first temperature change amount calculation means. A second temperature change amount for calculating the temperature change amount of the infrared detection means based on the calculated temperature change amount of the temperature detection means and the difference in thermal characteristics between the infrared detection means and the temperature detection means. It is desirable to be constituted by a calculation means.
[0013]
Furthermore, the thermal characteristics are preferably heat capacity and thermal conductivity.
[0014]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
As shown in FIG. 2, the ear-type thermometer 1 is provided with a probe 2 to be mounted in the ear, a thermopile 3 disposed at a proximal end portion of the probe 2, and a thermopile 3 in the vicinity of the thermopile 3. At least a thermistor 4 that detects a temperature that approximates the temperature at one end (reference temperature), and a control circuit 5 that is described below, and detects body temperature by detecting infrared rays emitted from the ear, specifically the eardrum 18. , To display.
[0016]
The control circuit 5 is provided in the main body of the ear-type thermometer 1. The amplifier (A) 6 amplifies the signal from the thermopile 3, and converts the signal amplified by the amplifier 6 into a digital value. An A / D converter (A / D) 7, an amplifier (A) 8 for amplifying a signal from the thermistor 4, a reference voltage circuit (RV) 9 for supplying a reference voltage to the amplifier 8, the reference voltage circuit 9 and the following A power supply circuit (BC) 10 for supplying power to a microprocessor unit (MPU) 13, a battery (B) 11 as a power supply for the power supply circuit 10, at least a central processing unit (CPU) (not shown), a read-only memory (ROM) ), An MPU 13 including a random access memory (RAM), an input / output port (I / O), etc., and an electrically erasable / writable ROM (EEPROM) mounted on the MPU 13 5, at least constituted by a switch circuit (SWITCH) 14, a display circuit (DISPLAY) 16 and a modem to perform temperature display, a communication circuit 17 or the like having a transmission terminal connectable to a mobile terminal having an operation switch.
[0017]
The control circuit 5 having the above configuration processes a signal in accordance with a program written in the EEPROM 15, for example. Hereinafter, a control routine as an example of the processing will be described with reference to the flowchart shown in FIG.
[0018]
When a switch (not shown) connected to the switch circuit 14 is turned on, a control routine starts from Step 200, and power is supplied from the power supply circuit 10 to each unit in Step 210. First, at step 220, the output THM (t0) of the thermistor 4 is read. Further, in step 230, the output THP from the thermopile 3 is read. In step 240, the output THM (t1) of the thermistor 4 is read simultaneously with or immediately after reading the thermopile 3 (after t1 time).
[0019]
In step 250, temperatures T (thm) (t0) and T (thm) (t1) corresponding to the outputs are calculated from the outputs THM (t0) and THM (t1) of the thermistor, and in step 260, Based on the calculation result of step 250, the temperature change rate ΔT (thm) of the thermistor is calculated. As an example, the calculation is performed by, for example, a mathematical expression [ΔT (thm) = {T (thm) (t1) −T (thm) (t0)} / (t1−t0)].
[0020]
In step 270, the reference temperature Tzero of the thermopile 3 is calculated based on the temperature change rate ΔT (thm) of the thermistor 4 calculated in step 260. As an example, based on the temperature change rate ΔT (thm) of the thermistor 4 and the difference in heat capacity between the thermistor 4 and the thermopile 3 (ΔHcap), the temperature change rate ΔT (thp) of the thermopile 3 is expressed by, for example, the formula [ ΔT (thp) = A · F (ΔTthm, ΔHcap) + K1]. Based on the temperature change rate ΔT (thp) of the thermopile 3 and the reading time tr of the output THP by the thermopile 3, the reference temperature Tzero is, for example, This is calculated by the mathematical formula [Tzero = B · ΔT (thp) · t2 + K2]. In the above formula, A and B are arithmetic constants, and K1 and K2 are correction terms.
[0021]
In step 280, the relative temperature T (thp) is calculated from the output THP of the thermopile 3. In step 290, the ear temperature (body temperature) T (tag) is calculated from the reference temperature Tzero and the relative temperature T (thp). In step 300, the temperature is displayed as the body temperature via the display circuit 16, the power is turned off in step 310, and the control is terminated in step 320.
[0022]
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 actual thermopile 3 is read when the output of the thermopile 3 is read. And the temperature of the thermopile 3 when reading the output THM (t0) of the thermistor 4 or the temperature of the thermopile 3 when reading the output THM (t1) of the thermistor 4 is corrected. Therefore, an accurate reference temperature of the thermopile temperature can be obtained, and as a result, an accurate body temperature can be detected.
[0023]
【The invention's effect】
As described above, according to the present invention, based on the difference in the heat capacity and thermal conductivity of the thermistor, the temperature rise of the thermistor that rises when the ear thermometer probe is attached to the ear, and the temperature rise of the thermopile Since the error can be corrected, accurate temperature detection can be performed with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an 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 executed in the control device.
FIG. 4 is a characteristic diagram showing the 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]
DESCRIPTION OF SYMBOLS 1 Ear-type thermometer 2 Probe 3 Thermopile 4 Thermistor 5 Control circuit 18 Tympanic membrane

Claims (4)

Infrared detecting means for detecting infrared rays emitted from within the ear, temperature detecting means for detecting the temperature around the infrared detecting means, and a reference for calculating the reference temperature of the infrared detecting means based on the detection result of the temperature detecting means A temperature calculation means; a relative temperature calculation means for calculating a relative temperature from a detection result of the infrared detection means; an ear temperature calculation means for calculating an ear temperature from the reference temperature and the relative temperature; and the ear temperature calculation. In an ear thermometer comprising at least temperature display means for displaying the temperature in the ear calculated by the means as a body temperature,
Based on the detection result of the temperature detection means, a temperature change amount calculation means for calculating the temperature change amount of the infrared detection means, and based on the temperature change amount of the infrared detection means calculated by the temperature change amount calculation means. Comprising reference temperature correction means for correcting the reference temperature calculated by the reference temperature calculation means ,
The temperature change amount calculating means is calculated by the first temperature change amount calculating means for calculating the temperature change amount of the temperature detecting means from the detection result of the temperature detecting means, and the first temperature change amount calculating means. Second temperature change amount calculating means for calculating the temperature change amount of the infrared detecting means based on the temperature change amount of the temperature detecting means and the difference in thermal characteristics between the infrared detecting means and the temperature detecting means. A temperature correction device for an ear thermometer characterized by comprising: The temperature correction device for an ear-type thermometer according to claim 1, wherein the thermal characteristic is a heat capacity. The temperature correction apparatus for an ear-type thermometer according to claim 1 or 2, wherein the thermal characteristic is thermal conductivity.  The temperature correction apparatus for an ear-type thermometer according to claim 1 or 2, wherein the thermal characteristics are heat capacity and thermal conductivity.

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