JPH0370777B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the display method of an electronic thermometer using a temperature sensing element such as a thermistor.

When measuring body temperature, the surface of the body is colder than the deep part of the body, so if you place the thermometer close to the armpit, it will take 10 minutes for the temperature of the body surface under the armpit to reach equilibrium with the body temperature in the deep part. It takes more than a minute.

In this respect, electronic thermometers are no different from mercury thermometers.

However, with electronic thermometers, in order to shorten the apparent measurement time, it is assumed that the temperature of the probe increases in a constant relationship with the elapsed time, and the inflated value is balanced by a relatively simple addition process. The temperature can actually be displayed before the probe reaches equilibrium temperature.

However, the actual temperature rise curve cannot be expressed as a fixed function because it is influenced by the temperature at the time of temperature measurement, body surface temperature, perspiration of the subject, and other physical conditions, and is a complicated curve that includes variable coefficients. Even if calculations are performed, the displayed temperature measurement result will contain errors in the estimation calculation, but on the other hand, the estimated value, which can be obtained in a short period of time, is sufficiently effective as a trend or guide for body temperature.

Here, in order for the test subject to recognize the above trends and guidelines, the difference between the actual measured value and the estimated value should be determined over time, such as when the temperature is taken for 1 minute or 2 minutes. It's good to know. For this purpose, it may be possible to keep displaying both the actual measured value and the estimated value when taking the temperature.
This type of electronic thermometer is disadvantageous due to its geometrical and dimensional limitations.

The purpose of this invention is to make it easier to intuitively understand that the actual measured value and the estimated value approach and match over time during the temperature measurement, and to grasp the tendency of the body temperature, so that subsequent short-term temperature measurement using only the estimated value is possible. It is to be able to do it.

In order to achieve the above object, the present invention provides an electronic thermometer that includes a circuit that stores the highest temperature measured by a temperature sensing element, and a circuit that calculates an estimated final value of temperature measurement and stores the result. A switch is provided for connecting either one of the output sides of the circuit to the input side of the digital display.

Next, the configuration, operation, and effects of the electronic thermometer of the present invention will be explained using embodiments shown in the drawings.

In FIG. 1, reference numeral 1 denotes a temperature sensing element consisting of a thermistor protected by an aluminum cap, and is provided at the tip of a hollow shaft made of polypropylene that is integral with the main body case 4. 2 is a slide switch that turns the power ON/OFF, and 3 is a 3+1/2 digital liquid crystal display that displays the temperature measurement results. The total length of the thermometer is approximately 180mm
It is. Electronic components such as a temperature measurement circuit and a micro battery for power supply are housed inside the plastic main body case 4.

FIG. 2 is a circuit block diagram of this embodiment.

In the figure, 5 is an A-D converter that converts the electrical resistance value of the temperature-sensitive element 1 into temperature, and 6 is a clock signal generator that drives the A-D converter 5 at a cycle of 0.2 seconds to Prevents self-heating by applying electricity in pulses,
The accuracy of temperature measurement has been improved. 7 is a circuit that stores the highest value of the temperature measurement result, and is cleared by the reset signal generated after the power switch 2 is turned ON.After that, the temperature is measured according to the cycle of the clock signal generator 6, and the temperature is measured by the magnitude comparator. 8 always maintains the highest value. A register 9 stores the output of the A-D converter 5 delayed by a timer, for example, 10 seconds before. Reference numeral 10 denotes a temperature increase rate detector, specifically, a circuit that detects whether the result obtained by subtracting the contents of register 9 from the output of AD converter 5 is 0.1° C. or less. If the subtraction result is below 0.1°C, the signal becomes H, and if it is above, the signal becomes L. This output is latched until the power is turned off. Reference numeral 11 denotes an arithmetic circuit for estimating the equilibrium temperature, which adds a predetermined value (0.8° C. in the embodiment) to the contents of the maximum value holding circuit 7 and holds it. The selector 12 normally selects the highest value maintenance circuit 7, but
When the signal from the detector 10 is H, the estimated value calculation circuit 11 is selected. However, even if the signal is H,
When the display changeover switch 14 provided near the power switch 2 is pressed down, the output of the temperature rise rate detector 10 becomes invalid, the selector 12 selects the highest value holding circuit 7, and the contents are transferred to the decoder driver 1.
Transfer to 3. The decoder driver displays the temperature measurement result on the liquid crystal display 3.

Next, how to use the thermometer of the present invention will be explained.

When performing temperature measurement, turn on power switch 2.
As a result, all registers are cleared by the reset signal and the display becomes 0°C.

When the temperature sensing element 1 is inserted and held in the armpit, the body surface temperature increases. Approximately 40 seconds after the start of temperature measurement, the temperature increase rate decreases, so the calculation result by the estimated value calculation circuit 11, that is, the estimated equilibrium body temperature is displayed.
If you remove the thermometer from your armpit after one minute of measuring your temperature and look at the display, you can get an approximate body temperature in a short time. This is suitable for mass temperature measurement of children.

Next, if you want to know your body temperature accurately, you can press the display changeover switch 14 from time to time to read the highest value reached up to that point, and repeat this until the highest value stops rising. The highest value is maintained on the display unless the power switch 2 is turned off. Therefore, there is no need for re-measurement. In fact, you can get an accurate reading by holding the thermometer under your armpit for about 10 minutes.

According to the present invention, since the estimated calculated value and the actual measured value can be viewed alternately by pressing and releasing the switch 14, it is possible to grasp the error tendency of the estimated equilibrium body temperature of a certain individual under certain ambient conditions. If you know this error trend, you can accurately estimate your body temperature by measuring your temperature over a short period of time.

In the above embodiment, the display changeover switch 1 is
Although a push switch is used in 4, it is also possible to use a switch that divides the output of the clock signal generator and electronically switches the output at a constant cycle.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the electronic thermometer of the present invention, and FIG. 2 is a block diagram of the circuit of the thermometer of FIG. 1... Temperature sensing element, 2... Power switch, 3...
Liquid crystal display, 4... Main body case, 5... A-D converter, 6... Clock signal generator, 7... Maximum value holding circuit, 8... Magnitude comparator,
9...Register, 10...Temperature rise rate detector, 1
1...Equilibrium temperature estimation calculation circuit, 12...Selector, 13...Decoder driver, 14...Display switching switch.

Claims (1)

[Claims] 1 A device that is equipped with a temperature sensing element, its A-D converter, a circuit for storing the maximum value of the temperature sensing element, and a circuit for calculating the estimated final temperature measurement value and storing the result. An electronic thermometer equipped with a switching switch that switches either the output side of a circuit for storing memory or the output side of a circuit for storing estimated values to the input side of a digital display.