JPS5853295B2 - electronic thermometer - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electronic thermometer.

Conventionally, methods for determining body temperature using electronic thermometers include a prediction method and a maximum value holding method.

The prediction method is a method of predicting the true body temperature from the measured temperatures at, for example, two points in time after the start of body temperature measurement, and also includes an overlay method of adding a certain amount to the measured value.

Although this method has the advantage of being able to measure body temperature in a relatively short period of time, it has the disadvantage that accurate body temperature cannot be obtained because the predicted value is used as body temperature.

In this method, predictions are normally made on the assumption that the temperature characteristic curve versus time is an exponential function of a predetermined time constant, but since the time constant varies from person to person, it may be relatively accurate for a particular person. However, others have the disadvantage of being inaccurate.

On the other hand, the maximum value holding method is an example of the conventional mercury thermometer, in which if the measured value is higher than the previously measured value, that value is taken as the body temperature, and if it is lower, the previous value is taken as the body temperature3. With this method, accurate measurement is possible if the measurement time is long enough, but if the measurement time is short, the value will be much lower than body temperature.

Accurate body temperature measurement using the maximum value holding method has the disadvantage that it takes a relatively long time.

The present invention was made in view of the shortcomings of conventional electronic thermometers, and allows relatively accurate body temperature measurements even if the measurement time is short, and extremely accurate measurements if the measurement time is long. The purpose is to provide an electronic thermometer that can perform

The present invention measures the temperature detected by the temperature sensing element at predetermined intervals, compares and determines the measured value Tai with the highest temperature value Tm1-1 measured before then, and if Tai>Tm1-1, then Tai +k (Tai -Tmi-1) is also T
When ai < Tm1-1, the previously calculated Tai+
The value corresponding to k (Tai - Tmi-1) is output as the body temperature.

However, k is a predetermined number. That is, in the present invention, Tai>T
In the case of m1-1, the body temperature is obtained by the prediction method, but Ta
When i<T m i-1, the body temperature previously determined by the prediction method is maintained using the maximum value holding method.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a temperature sensing element such as a thermistor.

When body temperature measurement is started, each time the clock signal from the clock signal generation circuit 2 is supplied to the temperature measurement circuit 3,
This circuit 3 measures the temperature detected by the temperature sensing element applied to the subject.

This measured temperature is once stored in the memory circuit 4 and then input to the comparison circuit 5.

On the other hand, the maximum value holding circuit 6 is a circuit that stores and holds the maximum value of the temperature measured by the temperature measurement circuit 3, and the output of this circuit 6 is also input to the comparison circuit 5.

After the start of body temperature measurement, the i-th measured temperature in the temperature measurement circuit 3 is Tai, and the highest measured temperature in i-1 measurements held in the maximum value holding circuit 6 is Tm1-1. During the i-th measurement, the comparator circuit 5 compares Tai and T.
m1-1 is compared and determined.

When the comparator circuit 5 determines that Tai is a dog based on Tm1-1, the comparator circuit 5 sends a control signal to that effect to the arithmetic circuit 7.
sent to.

Then, the calculation circuit 7 calculates the measured value Tai stored in the storage circuit 4 and the output of the highest value holding circuit 6 from Tm1-1 to Tai +k (Tai - Tmi-1).

Thereafter, this calculation result is sent to the body temperature holding circuit 8 and held, and then digitally displayed as body temperature in the display circuit 9.

The display format may be analog.

On the other hand, as described above, in the comparator circuit 5, T a i >
When it is determined that Tm i-1, after the above calculation is performed,
The highest value holding circuit 6 stores Tai instead of Tm1-1.

This is Tm1-1.

Further, when the comparator circuit 5 determines that Tai<Tm1-1, a control signal to that effect is sent to the arithmetic circuit 7.

In this case, the calculation circuit 7 does not output the calculation result to the body temperature maintenance circuit 8, and the display circuit 9 displays the previously calculated Tai +k.
The value corresponding to (Tai - Tmi -1) continues to be displayed.

On the other hand, in this case, since Tai <Tm1-1, TmT
m1-1=T, and the highest value holding circuit 6 holds the previous highest value.

Note that when Tai=Tmi-1, even if the above calculation is performed, Toi=Tai.

Next, when the i+1th temperature measurement is performed in the temperature measurement circuit 3, the measured value Tai+1 at this time is temporarily stored in the storage circuit 4, and then the comparison circuit 5 stores this Tai+1.
+1 and Tmi are compared and determined, and the same operation follows.

The operation of the electronic thermometer of the above embodiment will be explained in more detail.

After the temperature sensing element 1 of this thermometer is put down and body temperature measurement starts, the temperature measurement circuit 3 automatically measures the temperature every time a clock pulse is output from the clock signal generation circuit 2, for example every 10 seconds. Assume that we obtained the measured value Tai as shown in the following table.

At this time, if the value initially held by the highest value holding circuit 6 is O, the highest value Tmi will be as shown in the table, and the arithmetic circuit 7
If k in the calculation is set to 1, the body temperature displayed by the display circuit 9 will be Toi.

That is, at the first measurement time t1, the measured temperature Ta is 25,
0, and the measured temperature initially increases each time the measurement is performed.

If this thermometer is taken out one minute after the start of measurement, the measured temperature will drop after the seventh measurement.

At the time of the first measurement, Tmo is OT, , is 25.0, and Ta1>Tmo, so T.

1=25.0+(25,0-0)=50.0.

Similarly, since it is TmO, T according to the second measurement at time t2.

2=30.0+(30,0-25,0)=35.0.

Since Tai > T m i-1 until the sixth measurement, the arithmetic circuit 17 performs the above-mentioned arithmetic and uses this as the displayed body temperature in the display circuit 9 .

However, in the seventh and subsequent measurements, Tai<Tm1-1, so the body temperature of the previous calculation results will continue to be displayed.

This situation is shown in Figure 2. If such an electronic thermometer is applied to the subject for 5 minutes, the steady value, for example 36.
If it reaches 7, then Tai = Tmi-1, so Toi = Tai + (Tai - Tai) =
Tai, a steady value of 36, 7 is displayed, and this temperature will be displayed even if the thermometer is taken out from now on.

In the above embodiment, the measured temperature is temporarily stored in the memory circuit 4, but this circuit is not necessarily necessary and the output of the temperature measuring circuit may be directly used for comparison.

Moreover, the arithmetic circuit 7 can be operated without using the body temperature maintenance circuit 8.
A new calculation may be performed and the result displayed only when i>Tm1-1.

In addition, the present invention is not limited to the circuit configuration shown in FIG.

Incidentally, in the above description, the case where k in the arithmetic expression of the arithmetic circuit 7 is set to 1 has been described.

However, the value of k does not necessarily have to be 1.

If the value of k is appropriately selected depending on the subject, the body temperature can be measured more accurately than in the above case even when the measurement time is short.

As explained above, according to the present invention, the measured temperature Tai measured at a predetermined time is the highest value T of the previously measured temperatures.
If higher than m1-1, Toi = Tai + k
(Tai - Tmi -1) is output as body temperature, T
When ai becomes lower than Tm1-1, the previously calculated Ta
A value corresponding to i+k(Tai-Tmi 1) is output.

Therefore, when the measurement time is relatively short, the predicted temperature calculated using a certain prediction method is output, and the calculation is repeated to display a more accurate body temperature.If the measurement time is long enough, the maximum temperature is displayed. Therefore, the shorter the measurement time, the more accurate the temperature will be, and the longer the measurement time, the more accurate the temperature will be.

Furthermore, the thermometer according to the present invention has the advantage of having a simple circuit configuration because it requires only a comparison circuit for Tai and Tm1-1 and the simple calculations described above.

Further, since the displayed temperature is maintained even if the temperature sensing element is removed, it is particularly suitable for a thermometer in which the temperature sensing element and the display section are integrated.

In addition, in the present invention, even if the measurement time becomes long, the highest value of the measured temperature is not directly held as the body temperature.

However, as the measurement time becomes longer, the fluctuation in the measured temperature decreases and Tai becomes approximately equal to Ta1-1 (Tmi -1), so Toi = Tai + k (Tai - 1) KiT
ai, and if the measured temperature drops thereafter, it is almost the same as displaying the highest value as body temperature.

If the measurement time is short, the predicted value immediately before the measured temperature drops will be displayed as the body temperature.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the relationship between the measured temperature Tai and the displayed temperature Toi in the embodiment of FIG. 1. 1...Temperature sensing element, 2...Clock signal generation circuit, 3...Temperature measurement circuit, 4...
・Memory circuit, 5... Comparison circuit, 6...
Maximum value holding circuit, 7... Arithmetic circuit, 8...
...Body temperature maintenance circuit, 9...Display circuit.

Claims (1)

[Claims] 1. A means for measuring the temperature detected by the temperature sensing element at predetermined intervals after the start of body temperature measurement, and a maximum value holding circuit for memorizing and holding the highest value of the measured temperature up to the time when the temperature is sequentially measured by this means. , means for comparing and determining the magnitude of the highest value Tm1-1 held in the highest value holding circuit and the measured value Tai next obtained by the measuring means, and determining by this means that at least Tai>Tm1-1. Tai + k (Tai − Tmi −
1) A calculation circuit that performs a % calculation and a temperature display based on the latest calculation result of the calculation circuit when Tai > Tm1-1 is determined by the comparison and determination means;
temperature display means for displaying a temperature based on a previous calculation result of the calculation circuit when it is determined that T ai >Tm1; An electronic thermometer characterized in that, when it is determined to be -1, the previous maximum value Tmi -1 is rewritten by Tai to update the maximum value.