WO2013136586A1

WO2013136586A1 - Electronic thermometer

Info

Publication number: WO2013136586A1
Application number: PCT/JP2012/079296
Authority: WO
Inventors: 大資石原
Original assignee: オムロンヘルスケア株式会社
Priority date: 2012-03-13
Filing date: 2012-11-12
Publication date: 2013-09-19
Also published as: JP2013190282A

Abstract

An electronic thermometer (1) is provided with: a temperature measurement unit (32) that has an oscillation circuit including a resistance thermometer (20); and a control unit (30) that intermittently drives the oscillation circuit at fixed time intervals, and calculates a temperature value on the basis of the frequency of a signal output from the oscillation circuit. The control unit (30) is configured so as to be able to change the driving time in the intermittent driving of the oscillation circuit, and has, in the period from measurement start to end, a period in which the driving time is a short time compared when measurement ends.

Description

Electronic thermometer

The present invention relates to an electronic thermometer.

A thermometer that uses a CR oscillation circuit including a resistance temperature detector such as a thermistor and measures temperature based on the oscillation frequency is known (see, for example, Patent Document 1).

In the thermometer described in Patent Document 1, the CR oscillation circuit is intermittently driven at a constant time interval, and the temperature is sampled at a constant time interval. Thereby, power consumption is reduced.

Further, in the thermometer described in Patent Document 2, the sampling interval is changed according to the change in the measured temperature, and when the temperature change is large, the sampling interval is shortened, while when the temperature change is small The sampling interval is extended. Thereby, reduction of power consumption is achieved.

Japanese Unexamined Patent Publication No. 59-97026 Japanese Laid-Open Patent Publication No. 10-160591

Electronic thermometers are typically supplied with operating power by small batteries such as button batteries and coin batteries. Therefore, electronic thermometers are required to reduce power consumption.

In the electronic thermometer, as in the thermometer described in Patent Document 2, when the sampling interval is changed in accordance with the change in the measured temperature, the timing at which the display of the temperature value is updated also changes, which may annoy the user. There is. For example, when the sampling interval is extended, there is a possibility that the display of the temperature value is not updated for a relatively long time, and the user may be worried about whether or not the measurement is properly performed.

Moreover, in the actual measurement type electronic thermometer, it is detected that the thermal equilibrium state is reached, and the measurement is completed. However, according to the sampling interval change mode in the thermometer described in Patent Document 2, the equilibrium state is obtained. As the value approaches, the sampling interval is extended, which may affect the detection of the equilibrium state and the measurement accuracy.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an electronic thermometer with reduced power consumption without degrading measurement accuracy.

A temperature measurement unit having an oscillation circuit including a resistance temperature detector, and a control unit for driving the oscillation circuit intermittently at a constant time interval and calculating a temperature value based on the frequency of a signal output from the oscillation circuit The control unit is configured to be able to change the driving time in intermittent driving of the oscillation circuit, and the driving time is shorter than the time when the measurement is completed in the period from the start to the completion of the measurement. Electronic thermometer with a period.

According to the present invention, the power consumption of the electronic thermometer can be reduced without reducing the measurement accuracy.

It is a perspective view which shows an example of the electronic thermometer for demonstrating embodiment of this invention. It is a perspective view which decomposes | disassembles and shows the electronic thermometer of FIG. It is a functional block diagram of the electronic thermometer of FIG. It is a circuit block diagram of the temperature measurement part of the electronic thermometer of FIG. It is a graph which shows an example of the signal waveform output from the oscillation circuit of the temperature measurement part of FIG. 4 with the change curve of the temperature value in body temperature measurement. It is a graph which shows the other example of the signal waveform output from the oscillation circuit of the temperature measurement part of FIG. 4 with the change curve of the temperature value in body temperature measurement. It is a graph which shows the other example of the signal waveform output from the oscillation circuit of the temperature measurement part of FIG. 4 with the change curve of the temperature value in body temperature measurement. It is a graph which shows the other example of the signal waveform output from the oscillation circuit of the temperature measurement part of FIG. 4 with the change curve of the temperature value in body temperature measurement.

1 and 2 show an example of an electronic thermometer for explaining an embodiment of the present invention.

The electronic thermometer 1 includes a case 2, a functional unit 3 and a battery 4 stored in the case 2.

The case 2 includes a main body 10 formed in a tapered hollow cylindrical shape, a cap 11 that closes an opening on the distal end side on the narrow side of the main body 10, and a cap 12 that closes an opening on the proximal end side of the main body 10. It consists of and.

As will be described in detail later, the functional unit 3 includes a resistance temperature detector 20 that detects the user's body temperature, an operation unit 33 that accepts operations such as power on / off by the user, a display unit 34 that displays the measured temperature, and the like. And a subassembly 21 on which is mounted.

The battery 4 is loaded into the base end of the main body 10 of the case 2. A cap 12 that closes the base-end opening of the main body 10 holds the battery 4 loaded in the base end of the main body 10.

The electronic thermometer 1 is used with the front end portion of the main body portion 10 in the case 2 sandwiched between the user's armpit or the tongue, and the cap 11 that closes the front end opening of the main body portion 10 is in close contact with the user. . The cap 11 is formed in a bottomed cylindrical shape using a metal material having excellent thermal conductivity such as a stainless alloy.

The main body 10 and the cap 12 are formed by injection molding using, for example, a thermoplastic hard resin material. Examples of the resin material used for the main body 10 and the cap 12 include ABS (acrylonitrile-butadiene-styrene copolymer) resin.

The resistance temperature detector 20 is disposed in the cap 11 and connected to the subassembly 21 via the lead wire 22. The user's body temperature is transmitted to the resistance temperature detector 20 through the cap 11 as thermal energy.

In the electronic thermometer 1 of this example, a thermistor is used for the resistance temperature detector 20. The resistance temperature detector 20 may be a platinum resistance temperature detector.

FIG. 3 shows the configuration of the functional unit 3.

The function unit 3 is roughly divided into a control unit 30, a storage unit 31, a temperature measurement unit 32, a notification unit 35, a power supply unit 36, and the operation unit 33 and the display unit 34 described above.

The control unit 30 is configured by, for example, a CPU (Central Processing Unit), and controls the operation of each unit of the functional unit 3.

The storage unit 31 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit 31 stores a program for causing the control unit 30 to execute a body temperature measurement process.

Although the details will be described later, the temperature measuring unit 32 includes the resistance thermometer 20 and measures the temperature of the user.

The operation unit 33 is configured by, for example, a push button type switch, receives an operation such as power on / off by a user, and inputs a control signal to the control unit 30 and the power supply unit 36 according to the operation.

The display unit 34 is configured by, for example, an LCD (Liquid Crystal Display), and displays a measured temperature value and the like.

The notification unit 35 is configured by a buzzer, for example, and notifies the user that the user's operation has been accepted or measurement has been completed.

The power supply unit 36 includes the battery 4 and supplies operating power to each unit of the functional unit 3 such as the control unit 30 and the temperature measurement unit 32.

The control unit 30, the storage unit 31, the temperature measurement unit 32, the operation unit 33, the display unit 34, the notification unit 35, and the power supply unit 36 are the subassembly 21 (FIG. 2) except for the battery 4 and the resistance temperature detector 20. Is implemented).

FIG. 4 shows the configuration of the temperature measurement unit 32.

In this example, the temperature measuring unit 32 measures the body temperature of the user using a CR oscillation circuit having the resistance temperature detector 20 as a load resistance. The control unit 30 calculates the temperature value based on the frequency (oscillation frequency) of the signal output from the CR oscillation circuit.

Hereinafter, the principle of temperature measurement based on the oscillation frequency of the CR oscillation circuit will be described.

The oscillation frequency f of the CR oscillation circuit is expressed by the following equation (1).

In equation (1), C represents the capacitance value of the capacitor, R represents the resistance value of the resistance temperature detector 20, and k represents a proportionality constant.

In this example, a thermistor is used for the resistance temperature detector 20, and the relationship between the resistance value R and the temperature T [k] is expressed by the following equation (2).

In Equation (2), R ₀ represents the resistance value of the thermistor when the temperature is T ₀ [k], and B represents the thermistor constant.

From the formula (1) and the formula (2), the temperature T [k] is expressed by the following formula (3).

In Equation (3), f ₀ represents the oscillation frequency when the temperature is T ₀ [k].

From Equation (3), the temperature of the resistance temperature detector 20 can be calculated based on the oscillation frequency of the CR oscillation circuit.

The temperature measuring unit 32 includes a resistance temperature detector 20, a reference resistor 42, a capacitor 43, an oscillation control circuit 44,

switch elements

45 and 46, and a counter 47.

The switch element 45 is interposed between the resistance temperature detector 20 and the oscillation control circuit 44, and the switch element 46 is interposed between the reference resistor 42 and the oscillation control circuit 44. The switch element 45 is opened and closed by the control unit 30. The The control unit 30 opens and closes the

switch elements

45 and 46 so that any one of the resistance temperature detector 20 and the reference resistor 42 is selectively connected to the oscillation control circuit 44.

By opening and closing the

switch elements

45 and 46, from the resistance temperature detector 20 and the capacitor 43 and the oscillation control circuit 44 (hereinafter referred to as a sensor oscillation circuit), or from the reference resistor 42 and the capacitor 43 and the oscillation control circuit 44 A CR oscillation circuit (hereinafter referred to as a reference oscillation circuit) is configured.

Each of the sensor oscillating circuit and the reference oscillating circuit is alternately and intermittently driven at a constant time interval by a control signal input from the control unit 30 to the oscillation control circuit 44. The signals output from these oscillation circuits are input to the counter 47, and the number of peaks in the change in the potential level is counted. The number of peaks counted by the counter 47 is taken into the control unit 30.

In the above configuration, first, the control unit 30 drives the reference oscillation circuit to perform reference oscillation. The control unit 30 continues driving the reference oscillation circuit until the number of peaks counted by the counter 47 reaches the specified number of times, and counts the driving time at that time.

The control unit 30 stops driving the reference oscillation circuit when the number of peaks of the signal output from the reference oscillation circuit reaches a specified number. Next, the control unit 30 drives the sensor oscillation circuit at a predetermined time interval to perform sensor oscillation. In this sensor oscillation, the control unit 30 drives the sensor oscillation circuit for the same time as the drive time of the reference oscillation circuit in the immediately preceding reference oscillation.

The control unit 30 acquires the peak number of the signal output from the sensor oscillation circuit during the period of driving the sensor oscillation circuit from the counter 47, and calculates the sensor from the acquired peak number and the driving time of the sensor oscillation circuit. Calculate the oscillation frequency of the oscillation circuit.

The sensor oscillation circuit and the reference oscillation circuit are substantially different only in the load resistance constituting the CR oscillation circuit. Therefore, by setting the driving time of the sensor oscillation circuit using the reference oscillation circuit as described above, error factors such as the temperature characteristics of the capacitor 43 and the oscillation control circuit 44 can be eliminated. The oscillation frequency of the sensor oscillation circuit can be calculated with high accuracy.

Then, the control unit 30 calculates the temperature value of the resistance temperature detector 20 based on the calculated oscillation frequency of the sensor oscillation circuit, and updates the display of the display unit 34 with the calculated temperature value.

The calculation of the temperature based on the oscillation frequency of the sensor oscillation circuit can be performed by, for example, an operation using a natural logarithm represented by Equation (3). It is also possible to obtain the relationship between the oscillation frequency and temperature in advance, store the temperature characteristics of the oscillation frequency in the storage unit 31 as a lookup table, and refer to this lookup table.

The control unit 30 intermittently repeats reference oscillation and sensor oscillation alternately at regular time intervals until the measurement of the body temperature is completed, samples the temperature value at regular time intervals, and updates the display on the display unit 34 To do.

・ Power consumption can be reduced by intermittently performing sensor oscillation and reference oscillation. Moreover, since the temperature value is sampled at a constant time interval and the display on the display unit 34 is updated, the user is not confused.

FIG. 5 shows an example of a temperature value change curve in body temperature measurement and signal waveforms output from the reference oscillation circuit and the sensor oscillation circuit.

The calculation accuracy of the oscillating frequency of the sensation oscillation circuit is affected by the driving time of the sensor oscillating circuit. Typically, the longer the driving time, the higher the calculation accuracy of the oscillating frequency, and the higher the measurement accuracy of the body temperature. In particular, when the oscillation frequency is calculated from the drive time of the sensor oscillation circuit and the peak number of signals output from the sensor oscillation circuit during that period, the influence of the drive time on the calculation accuracy of the oscillation frequency becomes significant.

For example, assuming that the sensor oscillation circuit is driven for time t, the number of peaks of signals output from the sensor oscillation circuit during that period is 10000 counts when the temperature of the resistance temperature detector 20 is 37.0 ° C. It is assumed that the count was 9600 at 0 ° C. In that case, the resolution is 0.0025 ° C. ((37.0-36.0) / (10000-9600)).

Assuming that the driving time of the sensor oscillation circuit is 2t, the peak number of signals output from the sensor oscillation circuit during that period is 20000 count when the temperature of the resistance temperature detector 20 is 37.0 ° C. and 36.0 ° C. Sometimes 19200 counts and the resolution is 0.0013 ° C. ((37.0-36.0) / (20000-19200)).

On the other hand, the power consumption increases as the driving time of the sensor oscillation circuit becomes longer.

Therefore, in the electronic thermometer 1 of this example, the drive time of the sensor oscillation circuit is appropriately changed in the period from the start of measurement of the body temperature to the completion of the measurement, and the drive time is shorter than the drive time at the time of completion of measurement. A period is provided. Note that the driving time of the sensor oscillation circuit at the time of completion of measurement is the driving time of the sensor oscillation circuit performed last in the measurement period.

In the body temperature measurement process described above, the driving time of the sensor oscillation circuit is the driving time of the reference oscillation circuit until the peak number of the signal output from the reference oscillation circuit reaches the specified number of times. The driving time of the sensor oscillation circuit can be changed by appropriately changing the specified number of times set for the number of peaks of the output signal of the oscillation circuit.

When measurement of body temperature is performed by an actual measurement formula, the measurement is completed when a thermal equilibrium state is formed between the user and the electronic thermometer 1. The controller 30 determines whether a thermally balanced state has been formed. For example, the control unit 30 uses a predetermined threshold for increase / decrease or change rate (absolute value) of the temperature value sampled at a constant time interval, and an equilibrium state is formed when the increase / decrease or change rate is smaller than the threshold. It is determined that

細 Fine resolution is required to determine whether or not an equilibrium state has been formed with high accuracy. For this reason, it is preferable that the driving time of the sensor oscillation circuit be relatively long at the end of measurement in which an equilibrium state or a quasi-equilibrium state is formed.

On the other hand, since the resolution is not required as early as the end of measurement, there is no problem even if the driving time of the sensor oscillation circuit is relatively short.

In the example shown in FIG. 5, the driving time of the sensor oscillation circuit is changed based on the elapsed time from the start of measurement.

The control unit 30 counts the elapsed time from the start of measurement, determines whether the elapsed time exceeds a predetermined threshold value t _th , and changes the driving time of the sensor oscillation circuit. The threshold for the elapsed time is that the time required for a thermal equilibrium between the user and the electronic thermometer 1 to be formed is approximately 10 minutes under the armpit and approximately 5 minutes under the tongue. For example, it can be set to 2 to 3 minutes.

But when the elapsed time is equal to or less than the threshold (initial measurement), the driving time of the sensor oscillator is a t _1, but when the elapsed time exceeds the threshold value (end of measurement), the driving of the sensor oscillator time is longer t ₂ than the drive time t ₁ in the initial.

Thus, at the initial stage of measurement, the power consumption can be reduced by making the drive time of the sensor oscillation circuit shorter than the drive time at the end of measurement (when measurement is completed).

And by increasing the driving time of the sensor oscillation circuit at the end of the measurement, the resolution can be improved and the measurement accuracy of the body temperature can be improved.

FIG. 6 shows another example of a temperature value change curve in body temperature measurement, and a signal waveform output from the reference oscillation circuit and the sensor oscillation circuit.

The example shown in FIG. 6 changes the driving time of the sensor oscillation circuit based on the temperature value because the temperature value typically increases monotonously in body temperature measurement.

The control unit 30 samples the temperature value at a constant time interval from the start of measurement, determines whether the temperature value T has exceeded a predetermined threshold value _Tth , and changes the driving time of the sensor oscillation circuit. The threshold value T _th for the temperature value can be set to 30 ° C., for example, considering that the room temperature is approximately 25 ° C. and the normal heat of the human body is approximately 36 ° C.

When the temperature value T is equal to or less than the threshold T _th (initial measurement), the driving time of the sensor oscillator is a t _1, when the temperature value T exceeds the threshold value T _th (end of measurement) is The driving time of the sensor oscillation circuit is t ₂ which is longer than the initial driving time t ₁ .

If the driving time of the sensor oscillation circuit is changed based on the temperature value T, the driving time is more appropriately timing than when the driving time of the sensor oscillation circuit is changed based on the elapsed time shown in FIG. Can be changed to further reduce power consumption.

The time (measurement period) required until a thermally balanced state is formed varies depending on, for example, the contact state between the user and the electronic thermometer 1, but the timing for changing the driving time according to a predetermined threshold value for the temperature value is set. If determined, the timing for changing the drive time can be changed in accordance with the fluctuation of the measurement period.

FIG. 7 shows another example of the temperature value change curve in the body temperature measurement and other signal waveforms output from the reference oscillation circuit and the sensor oscillation circuit.

The example shown in FIG. 7 is based on the temperature value difference because the temperature value typically increases monotonically in a logarithmic function and the temperature value difference sampled at regular time intervals gradually decreases. Thus, the driving time of the sensor oscillation circuit is changed.

The control unit 30 samples the temperature value at a constant time interval from the start of measurement, determines whether or not the temperature value difference ΔT exceeds a predetermined threshold value ΔT _th , and changes the driving time of the sensor oscillation circuit.

When the temperature value difference ΔT is equal to or greater than the threshold value ΔT _th (initial measurement), the driving time of the sensor oscillation circuit is t _1, and when the temperature value difference ΔT is less than the threshold value ΔT _th (end of measurement) ), The driving time of the sensor oscillation circuit is t ₂ which is longer than the driving time t ₁ in the initial stage.

FIG. 8 shows another example of the temperature value change curve in the body temperature measurement and the signal waveform output from the reference oscillation circuit and the sensor oscillation circuit.

In the example shown in FIG. 8, the temperature value in the body temperature measurement typically increases monotonically in a logarithmic function, and the rate of change per unit time of the temperature value sampled at regular time intervals gradually decreases. The driving time of the sensor oscillation circuit is changed based on the change rate of the value.

The control unit 30 samples the temperature value at regular time intervals from the start of measurement, determines whether or not the rate of change dT of the temperature value exceeds a predetermined threshold value dT _th and changes the driving time of the sensor oscillation circuit. .

When the change rate dT in the temperature value is the threshold value dT _th or more (initial measurement), the driving time of the sensor oscillator is a t _1, when the change rate dT in the temperature value is less than the threshold value dT _th (Measurement At the end of (2), the driving time of the sensor oscillation circuit is set to t ₂ which is longer than the driving time t ₁ in the initial stage.

If the drive time of the sensor oscillation circuit is changed based on the temperature value difference ΔT or the change rate dT, compared to the case where the drive time of the sensor oscillation circuit is changed based on the temperature value T shown in FIG. The driving time can be changed at a more appropriate timing to further reduce the power consumption.

The temperature value in the thermally balanced state varies depending on, for example, individual differences between users and the user's state, but the timing for changing the driving time is determined by the threshold value for the temperature value difference ΔT and the rate of change dT. Then, the timing for changing the driving time can be changed according to the fluctuation of the temperature value in the equilibrium state.

In each of the examples shown in FIGS. 5 to 8, the measurement period is divided into an initial period and an end period using one threshold value, and the driving time of the sensor oscillation circuit is set as an initial period (t ₁ ) and an end period (t ₂ ). However, the measurement period may be divided into three or more using a plurality of thresholds, and the drive time may be changed more finely.

When the measurement period is divided into three or more using a plurality of threshold values, for example, the driving time may be gradually increased from the initial stage to the final stage of the measurement, or the driving time may be set at the initial stage and the final stage of the measurement. The drive time in the middle period of measurement may be shortened by increasing the length.

Further, in the examples shown in FIGS. 5 to 8, the measurement period is divided into an initial period and an end period, the driving time is constant in each of the initial period and the final period, and the driving time is stepwise when transitioning from the initial stage to the final stage. However, for example, a predetermined calculation using variables such as elapsed time, temperature value sampled at a constant time interval, or a difference or change rate of the temperature value is performed, and continuous calculation is performed based on these variables. Alternatively, the driving time may be changed.

Moreover, although the case where the measurement of the body temperature is performed using the actual measurement formula has been described, also in the case where the measurement is performed using the prediction formula, the driving time of the sensor oscillation circuit is shorter than the driving time at the completion of the measurement in the measurement period. By providing the period, it is possible to reduce power consumption without reducing measurement accuracy.

When the body temperature is measured by a prediction formula, the measurement is completed before the thermal equilibrium state is formed, and the body temperature is determined based on a change curve of the temperature value sampled during the measurement period. Predicted by calculation.

In order to predict body temperature with high accuracy, it is necessary to acquire a temperature value change curve with high accuracy, and in particular, the accuracy of the temperature value change curve at the end of measurement is important. Therefore, at the end of measurement, the drive time of the sensor oscillation circuit is lengthened to improve resolution, and at the beginning of measurement, the drive time of the sensor oscillation circuit is shorter than the drive time at the end of measurement (when measurement is completed). If so, power consumption can be reduced without degrading measurement accuracy.

In addition, when shifting to measurement based on measurement formula after completing measurement based on prediction formula, the period after transition to measurement formula is set as a new measurement period, and as described above, the sensor oscillation circuit The drive time may be shorter than the drive time when the measurement is completed. According to this, power consumption can be further reduced.

As described above, the following items are disclosed in this specification.

(1) A temperature measurement unit having an oscillation circuit including a resistance temperature detector, and the oscillation circuit is driven intermittently at a constant time interval, and a temperature value is calculated based on the frequency of a signal output from the oscillation circuit And a control unit configured to change a driving time in intermittent driving of the oscillation circuit, and in a period from the start of measurement to completion, the driving time is shorter than that at the time of completion of measurement. Electronic thermometer with a period that is time.
(2) The electronic thermometer according to (1), wherein the control unit is output from the oscillation circuit based on the drive time and a peak number of signals output from the oscillation circuit within the drive time. An electronic thermometer that calculates the frequency of the signal.
(3) The electronic thermometer according to (1) or (2), wherein the control unit changes the driving time based on an elapsed time from the start of measurement.
(4) The electronic thermometer according to (1) or (2), wherein the control unit changes the driving time based on the calculated temperature value.
(5) The electronic thermometer according to (1) or (2), wherein the control unit changes the driving time based on a difference between the calculated temperature value and a temperature value calculated at the previous driving time. .
(6) The electronic thermometer according to (1) or (2), wherein the control unit changes the driving time based on a rate of change of the calculated temperature value per unit time.

According to the present invention, it is possible to provide an electronic thermometer with reduced power consumption without reducing measurement accuracy.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on March 13, 2012 (Japanese Patent Application No. 2012-056027), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 Electronic thermometer 2 Case 3 Function part 4 Battery 10 Main body part 11 Cap 12 Cap 20 Resistance temperature detector 21 Subassembly 22 Lead wire 30 Control part 31 Storage part 32 Temperature measurement part 33 Operation part 34 Display part 35 Notification part 36 Power supply part 42 Reference resistor 43 Capacitor 44 Oscillation control circuit 45 Switch element 46 Switch element 47 Counter

Claims

A temperature measurement unit having an oscillation circuit including a resistance temperature detector;
A controller that intermittently drives the oscillation circuit at regular time intervals and calculates a temperature value based on a frequency of a signal output from the oscillation circuit;
With
The control unit is configured to be able to change a driving time in intermittent driving of the oscillation circuit,
An electronic thermometer having a period in which the driving time is shorter than that at the time of completion of measurement in a period from the start of measurement to completion.
The electronic thermometer according to claim 1,
The control unit is an electronic thermometer that calculates a frequency of a signal output from the oscillation circuit from the driving time and the number of peaks of the signal output from the oscillation circuit within the driving time.
The electronic thermometer according to claim 1 or 2,
The said control part is an electronic thermometer which changes the said drive time based on the elapsed time from the measurement start.
The electronic thermometer according to claim 1 or 2,
The said control part is an electronic thermometer which changes the said drive time based on the calculated temperature value.
The electronic thermometer according to claim 1 or 2,
The said control part is an electronic thermometer which changes the said drive time based on the difference of the calculated temperature value and the temperature value calculated at the time of last drive.
The electronic thermometer according to claim 1 or 2,
The said control part is an electronic thermometer which changes the said drive time based on the change rate per unit time of the calculated temperature value.