JPH0371649B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronic thermometer using a temperature-sensitive element such as a thermistor, and particularly to means for ensuring accuracy when shortening measurement time.

[Prior art] In armpit temperature measurement, which is the most common method of measuring body temperature, since the surface of the body under the armpit is generally colder than the deep body temperature, after starting lateral temperature measurement, the body temperature is measured by placing the armpit in close contact with the body. A measurement time of about 10 minutes or more is required for the surface temperature to equilibrate to the body temperature, and even if an electronic thermometer is used, a long measurement time is required due to the heat transfer in the living body, similar to the glass thermometer. Therefore, in order to shorten the measurement time, we assume that the temperature rise rate of the probe is a constant function of time, stop the measurement before the probe reaches equilibrium temperature, and raise the temperature using a relatively simple addition process. Display type electronic thermometers are currently on the market.

[Problem that the invention seeks to solve]

However, the inventors' research on body temperature measurement revealed that the actual time-versus-temperature rise curve is easily influenced by the outside temperature, body surface temperature, the subject's physical condition such as sweating, the material of the probe, etc. It cannot be expressed by a fixed function, and there are large individual differences. Therefore, the occurrence of errors is unavoidable in the temperature measurement method, which is calculated assuming that the temperature rise characteristic is constant with respect to time.

Even in a thermometer having the calculation means described above so as to enable inferential temperature measurement, there is a need for a device that also has the conventional function of displaying sequential actual measurement results and allows the user to easily select between the two types of temperature measurement methods.

The simplest electronic thermometer with a calculation function that detects when the rate of temperature rise has fallen below a predetermined value and displays the temperature of the temperature sensing element by a predetermined value.
In order to minimize battery consumption, when temperature measurement is started by, for example, turning on the power after holding the device under the armpit for a sufficient period of time, a predetermined value will be displayed on top of the temperature of the thermosensor, which has already reached the body temperature. There was a problem with the device not displaying accurate body temperature.

[Object of the Invention] The present invention was made in view of the above problems, and its purpose is to eliminate measurement errors in inferential temperature measurement.

An object of the present invention is to correctly display a measured value even when an electronic thermometer that performs estimated temperature measurement takes the temperature in the shortest energization time.

[Summary of the Invention] The electronic thermometer of the present invention includes a temperature sensing element, a means for measuring and displaying the temperature of the temperature sensing element, and a temperature detection device for detecting whether the temperature sensing element has reached the body temperature range or the outside temperature range. means, and means for detecting a rate of temperature rise;
estimated value calculation means for estimating an equilibrium temperature when the rate of temperature increase decreases to a certain predetermined value; and within a predetermined time after the start of temperature measurement, the temperature increase rate detection means detects the predetermined value, and the temperature detection means When it is detected that is in the body temperature range, a selection instruction means is provided for prohibiting the display of the output of the estimated value calculation means, and the actual measured value is displayed, thereby preventing display of erroneous calculations.

[Embodiments of the invention] Next, embodiments of the present invention will be described.

FIG. 1 is an external perspective view of an electronic thermometer according to the present invention. Reference numeral 1 denotes a temperature sensing element consisting of a thermistor and an aluminum cap to protect it, and is integrated with the main body 4 through a hollow shaft made of polypropylene resin. 2 is a power on/off slide switch. 3 is a 3+1/2 decimetre liquid crystal display that displays the temperature measurement results. 4 is an ABS resin main body case,
Inside, electronic components such as a temperature measurement circuit (not shown) and a power supply micro battery are housed.

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

5 is an A/D converter which converts the electrical resistance value corresponding to the temperature of the temperature sensing element 1 into a digital temperature value.
After turning on the power switch 2, the temperature sensing element 1 is energized intermittently by the clock 6.
The A/D converter 5 also outputs periodic measurement results using the clock 6. In this embodiment, measurements are made every 200 ms. Reference numeral 7 denotes a maximum value holding means that compares the previous measured value of the periodic measurement with the current measured value (output of the A/D converter 5), and when the current measured value is high, takes in and holds it. Reference numeral 8 denotes estimated value calculation means, and in this embodiment, maximum value holding means 7
Add a predetermined value (0.8℃) to the contents of . 9 is a selector which selects the highest value holding means 7 when the output of the selection instruction means 10 (described later) is "L", selects the estimation calculation means 8 when the output of the selection instruction means 10 is "H", and selects the data The data is transferred to the driver 11. The data driver 11 outputs "L0" when the data transferred from the selector 9 is below 35°C.
When the temperature is 42 degrees Celsius or higher, it is decoded to display "HI", and at other times the electrical signal is converted so that it can be displayed on the liquid crystal display 3 as a 3-digit number. FIG. 3 is an internal circuit diagram of the selection instruction means. 12
is a temperature rise rate detection means, which is composed of a register that holds the A/D converter output from 10 seconds ago, a subtraction means, and a comparison means, and is configured to detect a predetermined value, for example, 0.1°C or less, with a temperature rise for 10 seconds. When the state is normal, it outputs "H", and in the normal state, it outputs "L". 13
is a temperature detection means which outputs "L" when the output of the A/D converter 5 is in the body temperature range, for example, 35°C or higher, and outputs "H" when it is in the outside temperature range, for example, below 35°C. 1
4 is a timer that starts when the power switch 2 is turned on when temperature measurement starts, and the signal output becomes "H" for a predetermined period of time, for example, 100ms to 400ms, which is much shorter than the time it takes to reach the equilibrium temperature during normal temperature measurement after the timer starts. Otherwise, "L" is output.
15 is a 2-input AND circuit, 16 is the 2-input
It is a means of AND circuit output. 17 is an inverter circuit that inputs the output of the temperature detection means 13; 18 is 3;
It is an input AND circuit. 19 is a latch means for the output of the three-input AND circuit. Latching means 16,1
9, within 100ms immediately after turning on the power switch 2,
It is reset and the output is set to "L". 20 is the latch 19 output.

The operation of this embodiment with the above configuration will be explained next. If the temperature sensing element 1 is not in the body temperature range but in the outside temperature range and starts temperature measurement by turning on the power switch 2, the timer 14 starts and the output becomes "H" for 100ms to 400ms, and Since the temperature of temperature sensing element 1 is lower than 35℃,
The temperature detection means 13 detects that the temperature is in the outside temperature range, and the signal becomes "H". 2 input AND circuit 1
Since the temperature detecting means 13 and the timer circuit 14, which are inputs thereof, are both at "H", the circuit 5 outputs "H", which is held in the latch means 16. At this time, the inverter circuit 17 output is "L",
Since the output of the latch means 19 becomes "L", the selector 9 selects the highest value holding means 7, but since the content data is below 35°C, the decoder 11 detects this, and the display 3 shows the highest value. Instead of the contents of the value holding means 7, "L□" is displayed. When the temperature sensing element 1 is inserted into the armpit and the subject puts the armpit in close contact with it,
Since the body surface temperature in the armpit approaches the body temperature, the temperature increase rate of the temperature sensing element increases, and the temperature increase rate detection means 1
2 outputs an "L" signal. When the temperature sensing element 1 exceeds 35°C, the temperature detection means 13 detects that it is in the body surface area, and its output becomes "L", and the output of the inverter circuit 17 connected thereto becomes "H".
Of the inputs of the 3-input AND circuit 18, latch means 1
6 and the inverter circuit 17 outputs are both "H", and a system is in place to enable inferential temperature measurement. At this time, the output of the 3-input AND circuit 18 is "L" and its latch means 19 is also "L", so the selector 9 selects the highest value holding means 7 and sends its contents to the decoder driver 11 as a signal for liquid crystal display. and displays it on the display 3 as a 3-digit number. Approximately 1 minute after the reading starts, the body surface temperature under the armpits approaches body temperature.
The temperature increase rate of the temperature sensing element 1 becomes low, and when the temperature value measured 10 seconds ago is compared with the current output of the A/D converter 5, the difference between them becomes 0.1° C. or less. At this time, the temperature rise rate detection means 12 outputs "H", and the 3 inputs
Since all the inputs of the AND circuit 18 are "H",
The output becomes "H" and is held by the latch means 19. Since the selection instructing means 10 outputs "H" from the above, the selector 9 selects the estimated value calculation means 8 in place of the highest value holding means 7 which had been fetched up to that point. The estimated value calculating means 8 is the highest value holding means 7.
Since 0.8℃ is added to the content of , display 3 shows:
An estimated temperature measurement value higher than the current temperature of the temperature sensing element 1 is displayed.

When the temperature measurement is stopped after 2 minutes and the temperature sensing element 1 is pulled out from the armpit, the temperature of the temperature sensing element 1 suddenly drops to the outside temperature range, becomes less than 35℃, and receives 3 inputs.
The input is "L" from the inverter circuit 17 of the AND circuit 18, but the selection instruction means 10 outputs "H" held in the latch means 19, so the subject can read the result of calculating the equilibrium temperature. Display 3
You can check it above. The above is an explanation of the operation of a general estimated temperature measurement, and next, a method of use for reducing battery consumption will be explained.

Hold the thermosensor 1 under your armpit without turning on the power switch 2, wait until the body surface temperature under your armpit approaches your body temperature (about 10 minutes), and turn on the power switch 2 when the thermosensor 1 is under your armpit. , pull out the electronic thermometer. 100 immediately after turning on power switch 2
After ms, the thermistor is energized at a cycle of 200ms,
In the maximum value holding means 7, the signal of the temperature sensing element 1 whose temperature has reached the same temperature as the body temperature is A/D converted by the A/D converter 5, and is held as the body temperature.

Temperature increase rate detection means 12 in selection instruction means 10
Since the temperature increase rate has already reached a predetermined value, for example, 0.1° C./10 seconds or less, it outputs “H” and announces the establishment of inferential temperature measurement.

Body temperature is generally 35℃ or higher, and temperature detection means 1
3 outputs "L", and inverter circuit 17 outputs "H". However, 100ms immediately after energization
Temperature detection means 13 output at ~400ms is also “L”
Therefore, the 2-input AND circuit 15 outputs "L", and the latch means maintains the "L" state.
The 3-input AND circuit 18 outputs "L", and its latch means 19 also outputs "L" and never becomes "H". Therefore, even if the temperature increase rate is below a predetermined value, the selector 9 does not select the estimated value calculating means 8, prohibits the display of this value, and instead selects the maximum holding means 7, and displays its contents. The body temperature of the person is displayed on the display 3.

As is clear from the above explanation, in the electronic thermometer of the present invention, the temperature of the thermosensing element 1 is checked immediately after energization, and if the temperature sensing element is already 35°C or higher immediately after energization, the estimated temperature measurement is invalidated. Even if you turn it on at the wrong time, it will calculate the temperature even further on top of your body temperature and will not display an incorrect temperature measurement result.

[Effects of the Invention] The electronic thermometer of the present invention includes a temperature sensing element, a means for measuring and displaying the temperature of the temperature sensing element, and a temperature detection device for detecting whether the temperature sensing element has reached the body temperature range or the outside temperature range. means, and means for detecting a rate of temperature rise;
estimated value calculating means for estimating an equilibrium temperature when the rate of temperature increase decreases to a certain predetermined value; and within a predetermined time after the start of temperature measurement, the temperature increase rate detecting means detects the predetermined value, and the temperature detecting means When detecting that the temperature is in the body temperature range, a selection instruction means is provided that prohibits the display of the output of the estimated value calculation means, so that actual temperature measurement and estimated temperature measurement can be performed using a mechanical switch on the main body. It is possible to effectively switch the electronic thermometer without providing it, and the electronic thermometer can be easily handled. The electronic thermometer of the present invention calculates and presents the equilibrium temperature by measuring the temperature in a short period of about 1 minute, and also calculates and presents the equilibrium temperature by measuring the temperature in a short time of about 1 minute.
It can prevent temperature measurement errors due to extra layering.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of an electronic thermometer according to an embodiment of the present invention, FIG. 2 is a circuit block diagram of this embodiment, and FIG. 3 is a configuration diagram of a selection indicating means. 1... Temperature sensing element, 2... Power switch, 7...
Maximum value holding means, 8... Estimated value calculation means, 10...
...Selection instruction means, 12...Temperature increase rate detection means, 1
3...Temperature detection means.

Claims (1)

[Scope of Claims] 1. A temperature sensing element, means for measuring and displaying the temperature of the temperature sensing element, temperature detection means for detecting whether the temperature sensing element has reached the body temperature range or the outside temperature range, and temperature rise. means for detecting the temperature increase rate; estimated value calculation means for estimating the equilibrium temperature when the temperature increase rate decreases to a certain predetermined value; and the temperature increase rate detection means detects the predetermined value within a predetermined time after the start of temperature measurement. 1. An electronic thermometer, comprising selection instruction means for prohibiting display of the output of the estimated value calculation stage when the temperature detection means detects that the temperature is in the body temperature range.