JPH0365484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic thermometer, and particularly relates to an electronic thermometer suitable for converting the temperature of a contact area into an electrical signal and displaying it.

Among electronic thermometers that are sensitive to the temperature of the contact area, convert the temperature of the contact area into an electrical signal, and display the temperature of the contact area digitally, the minimum display unit is generally in 0.1℃ increments. There is. or,
When measuring body temperature with an electronic thermometer, it is common to insert the electronic thermometer into the armpit. It takes about 10 minutes to accurately measure the temperature under the armpit. This is because it takes about 10 minutes for body temperature to travel through the fat layer inside the body and reach the lower body surface of the armpit, which is isolated from the outside air.

By the way, an electronic thermometer includes a temperature-sensing part that is sensitive to the temperature of the contact area and outputs an electrical signal according to the temperature of the contact part, a display part that displays the temperature based on the output signal of the temperature-sensing part, and the display. It consists of a power supply unit that supplies power to the other parts. The display part consumes very little current as it is made up of elements such as C-MOS and liquid crystal display elements that have low current consumption, but the temperature sensing part uses a thermistor or thermistor that is sensitive to the temperature of the contact area. Since the A/D converter that converts the output of the electronic thermometer into an electrical signal is constructed of a linear circuit, the current consumption is large, and the life of the battery that constitutes the power supply section of the electronic thermometer is shortened. However, although it is possible to extend the life of the battery by intermittently energizing the temperature-sensing part, it is not possible to measure temperature sufficiently by simply energizing the temperature sensor intermittently. In the case of armpit temperature measurement, it takes about 10 minutes for the body surface temperature in the armpit to reach body temperature.

By the way, if we look at the rise in body temperature 3 minutes after the start of temperature measurement, the rate of rise is 0.1°C every 2 to 3 minutes. Moreover, since the temperature of an electronic thermometer is displayed in increments of 0.1°C, in order to extend the battery life, it is not a practical problem to energize the temperature sensing part once every 5 seconds, for example.

However, electronic thermometers are not only used to measure temperature under the armpit, but also under the tongue. In the case of this sublingual temperature measurement, there is a possibility that the temperature measurement may be terminated 30 to 40 seconds after the start of the measurement, so if the energization cycle was set to about once every 5 seconds, there was a problem that the error would become large.

The present invention has been made in view of the above problems,
The purpose is to reduce power consumption and
To provide an electronic thermometer capable of measuring temperature according to temperature measuring time.

In order to achieve the above object, the present invention provides a temperature sensing part that is sensitive to the temperature of a contact area and outputs an electrical signal according to the temperature of the contact part, and a display that displays the temperature based on the output signal of the temperature sensing part. and a power supply section that supplies power to the temperature sensing section, the electronic thermometer comprising: a plurality of power cutoff circuits that cut off the output of the power supply section at a predetermined cycle; and an output signal of the temperature sensing section. The rate of increase and change in temperature is calculated based on the temperature increase and the rate of change in temperature is compared with a set value determined corresponding to the disconnection cycle of the power source circuit and disconnection circuit, and the temperature increase is calculated based on the output of the temperature sensing section. An arithmetic circuit that outputs a comparison signal every time the rate of change reaches the set value, and a selection circuit that selects one of the outputs of the power source or disconnection circuit based on the output of the arithmetic circuit and supplies the selected output to the electric power source, The present invention is characterized in that when the rate of increase becomes smaller than the set value, the selection circuit selects the output of the power cutoff circuit having a cycle with a higher cutoff/energization ratio.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an external view of an electronic thermometer according to the present invention. In the figure, a temperature sensing element 3 provided at the tip of a probe shaft 2 fixed to a main body case 1 includes a thermistor inside and is covered with an aluminum cap. In addition, the main body case 1 includes a switch 4 for operating the start of temperature measurement and a liquid crystal display 5 for digitally displaying the temperature measurement result.
is provided.

FIG. 2 shows an internal configuration diagram of the electronic thermometer shown in FIG. 1.

The electronic thermometer in this embodiment includes a temperature sensing section 10,
Display section 12, power supply section 14, power supply disconnection circuit 16,
It is composed of an arithmetic circuit 18 and a selection circuit 20.

The temperature sensing section 10 includes a temperature sensing element 3 such as a thermistor that is sensitive to the temperature of a contact area, and an A/D converter 22 that converts the output of the temperature sensing element 3 into an electrical signal and converts this electrical signal into a digital signal. It is configured. The display section 12 includes a register 24, a magnitude comparator 26, a liquid crystal driver 28, and a liquid crystal display 5. The register 24 is a register that records the measured numerical value that is the output signal of the A/D converter 22, and the magnitude comparator 26 compares the numerical value stored in the register 24 with the numerical value of the A/D converter 22. This is a comparator that transfers the value to the register 24 when the value of the A/D converter 22 is large. Therefore, the highest value of the temperature measurement results is stored in the register 24.
The liquid crystal driver 28 has 2 bits held in the register 24.
The temperature measurement result in decimal or decimal format is converted into a liquid crystal drive signal corresponding to the segment constituting the liquid crystal display 5, and the signal is supplied to the liquid crystal display 5. The liquid crystal display 5 is composed of a 7-segment display element, and digitally displays the temperature measurement result in response to a liquid crystal drive signal from the liquid crystal driver 28.

The power cutoff circuit 16 includes timers 30 and 32 that cut off the output of the power supply section 14 at predetermined intervals. The energization time of timers 30 and 32 is
ON time is 6mS each, OFF time is timer
30 is 0.2 seconds, that is, the cutoff/energization ratio is 200/6, and timer 32 is 2 seconds, that is, the cutoff/energization ratio is 200/6.
It is said to be June 2000. The outputs of timers 30 and 32 are supplied to selection circuit 20, respectively. Selection circuit 20
selects one of the outputs of the timers 30 and 32 based on a comparison signal from an arithmetic circuit, which will be described later, and supplies the selected output to the A/D converter 22.

The arithmetic circuit 18 is composed of a detection path 34 and a flip-flop 36. The detector 34 includes a register, an arithmetic unit, etc., and calculates the rate of temperature increase and change based on the output signal of the A/D converter 22, and calculates the rate of increase and change in temperature based on the rate of increase and change in temperature and the cycle of the power supply shield circuit 16. A corresponding set value, for example 0.02° C., is compared and calculated, and a detection output is supplied to the flip-flop 36 when the rate of temperature rise change based on the output of the A/D converter 22 reaches the set value. The flip-flop 36 holds the detection output and selects the comparison signal from the selection circuit 2.
Supply to 0. At this time, the selection circuit 20
2 is selected and supplied to the A/D converter 22. Note that the display section 12, the power cutoff circuit 16, the arithmetic circuit 18, and the selection circuit 20 are constructed using C with low power consumption.
- Consists of MOS.

This embodiment has the above-mentioned configuration, and its operation will be explained next.

When measuring the temperature under the armpit using the electronic thermometer shown in Figures 1 and 2, turn off the power switch 4.
Turn it on and insert the temperature sensing element 3 into your armpit. At this time, power is supplied to the temperature sensing element 3 and the A/D converter 22 at the energization period by the timer 30, that is, every 0.2 seconds. The temperature measured by the temperature sensor 10 is stored in the register 24, and the temperature measurement result is displayed on the liquid crystal display 5 via the liquid crystal driver 28. In this case, even when power is not supplied to the A/D converter 22 by the timer 32, the measurement result of the temperature measurement by the temperature sensor 10 is stored in the register 24, so that the display on the liquid crystal display 5 is It will never go away. In other words, the minimum unit of display on the liquid crystal display 5 is 0.1°C.
However, for reasons such as adjustment, the A/D converter 22 and register 24 handle information every 0.01°C, which is one digit more than this.

After 2 minutes have passed since the armpit temperature measurement started, the register 2 records the rate of increase in temperature of the subject's body surface by 0.1°C per minute, that is, the output of the A/D converter 22 12 seconds ago.
When the output of the A/D converter 22 is subtracted from 4 and the value becomes smaller than the set value of 0.02°C, the detection output is supplied from the detector 34 to the flip-flop 36.
The selection circuit 24 is a timer 3 with a higher cutoff/energization ratio.
Select output 2. Therefore, the period of energization to the temperature sensing section 10 becomes approximately every 2 seconds, and the time until the next temperature measurement is delayed by 2 seconds. Here, if the temperature increase rate of the subject is constant, the temperature measurement interval is 2 seconds, so the detection cycle of the temperature increase rate becomes 10 times longer, and the output of the detector 34 disappears, but the flip-flop 3
6 continues to hold the output of the detector 34, the subsequent power supply cycle to the temperature sensing section 10 is at intervals of 2 seconds. Furthermore, since the temperature rise is 0.1° C. per minute and the display on the liquid crystal display 5 is every 0.1° C., no measurement error occurs even if the energization cycle is every 2 seconds.

In this way, in this example, the power consumption changes from energization every 0.2 seconds to every 2 seconds when the temperature rise change rate reaches the set value, so the power consumption when the temperature rise change rate reaches the set value is It becomes 1/10.

In addition, when sublingual temperature is measured using the electronic thermometer in this example, the temperature rises quickly immediately after the temperature measurement starts, but even if the temperature measurement is stopped in 20 seconds in a hurry, the temperature can be measured every 0.2 seconds. Therefore, the error due to the energization cycle being too slow is almost negligible.

In addition, in this embodiment, a method was described in which two timers were provided to cut off the output of the power supply unit and the timers were switched. Similarly to the embodiments described above, power consumption can be reduced by switching in multiple stages.

As explained below, according to the present invention, there is an excellent effect that power consumption can be reduced and temperature measurement can be performed according to the temperature measurement time.

[Brief explanation of drawings]

FIG. 1 is an external view of the electronic thermometer according to the present invention, and FIG. 2 is a configuration diagram showing the internal configuration of the electronic thermometer shown in FIG. 1. 3... Temperature sensing element, 5... Liquid crystal display, 10...
Temperature sensing part, 12...Display part, 14...Power supply part, 16
...Power cutoff circuit, 18...Arithmetic circuit, 20...
...selection circuit.

Claims (1)

[Claims] 1. A temperature-sensing section that is sensitive to the temperature of the contact area and outputs an electrical signal according to the temperature of the contact site, a display section that displays the temperature based on the output signal of this temperature-sensing section, and a device that supplies power to the temperature-sensing section. In an electronic thermometer that includes a power supply unit that supplies power and a plurality of cutoff circuits that cut off the power output at predetermined intervals, a rate of increase and change in temperature is determined based on an output signal of the temperature sensing unit. and a set value determined corresponding to a cutoff cycle of the power cutoff circuit, and outputs a comparison signal every time a temperature rise change rate based on the output of the temperature sensing section reaches the set value. and a selection circuit which selects one of the outputs of the power cutoff circuit based on the output of the arithmetic circuit and supplies the selected output to the temperature sensing section, and when the rate of increase in change becomes smaller than the set value, the selection circuit cuts off/off. An electronic thermometer characterized in that an output of a power cutoff circuit having a cycle with a higher Dentsu ratio is selected.