JP2003075263A - Electronic clinical thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic clinical thermometer that obtains complete waterproof performance, at the same time prevents the size from increasing, and prevents the price from increasing. SOLUTION: The electronic clinical thermometer comprises a thermosensitive oscillation circuit having a thermally sensitive element, a supply circuit, and a body temperature measuring circuit. By providing a temperature change detection circuit for outputting a temperature increase signal when a predetermined temperature is reached by detecting a temperature change, the supply circuit receives the temperature increase signal, thus operating the body temperature measuring circuit in a voltage output state.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electronic thermometer that does not require an externally operated power switch.

[0002]

2. Description of the Related Art A conventional electronic clinical thermometer uses an externally operated power switch such as a slide switch or a push switch, and therefore has a complicated structure and poor design.
Furthermore, there were problems such as poor waterproofness.

Since an electronic thermometer used especially in a hospital is immersed in an antiseptic solution for disinfection, it is required to have a completely waterproof performance. To solve this, a magnetic switch or a weight switch (for example, a special one) is used. An electronic thermometer using a power switch that does not use an externally operated member such as Kaikai 60-181624) has been proposed.

[0004]

The electronic thermometer using the above magnetic switch, weight switch, etc. surely has good waterproofness, but the switch structure is complicated and the shape is large, and the cost of parts is high, resulting in There is a problem that the price becomes high. The present invention solves the above problems, and realizes an electronic thermometer that achieves complete waterproof performance, does not increase the size, and does not increase the price.

[0005]

In order to solve the above problems, in the present invention, a temperature change is detected in an electronic thermometer having a temperature sensitive oscillation circuit having a temperature sensitive element, a power supply circuit, and a body temperature measuring circuit. A temperature change detection circuit that outputs a temperature increase signal when the temperature reaches a predetermined temperature, and the power supply circuit receives the temperature increase signal to enter a voltage output state to operate the body temperature measuring circuit. To do.

Further, it is characterized in that timer means is provided for returning the power supply circuit in the voltage output state to the voltage non-output state after a predetermined time.

Further, the temperature change detection circuit is also characterized in that it also serves as a temperature sensitive element of the temperature sensitive oscillation circuit to detect a temperature change.

Further, the temperature sensitive element is a thermistor.

[0009]

1 is a block diagram showing a circuit configuration of an electronic thermometer according to the present invention, in which 1 is a temperature-sensitive oscillation circuit having a temperature-sensitive element which will be described later, and 2 is a predetermined temperature sensor which detects a temperature change. The temperature change detection circuit 3 that outputs the temperature increase signal Th when the temperature reaches another temperature is a power supply circuit that outputs the power supply voltage Vd2 in a voltage output state by receiving the temperature increase signal Th.

Reference numeral 4 denotes a timer control circuit, which receives the supply of the power supply voltage Vd2 and outputs a timer signal Tm which is in an ON state for a certain period of time so that the temperature sensitive oscillation circuit 1, the temperature change detecting circuit 2 and the body temperature measuring circuit 5 are outputted. In addition to controlling each, the body temperature measurement circuit 5 receives the body temperature measurement end signal Te, and outputs the reset signal Rp at the end of the timer signal Tm to reset the power supply circuit 3 to the voltage non-output state. At the end of this timer signal Tm, the user finishes measuring the body temperature,
This is after a certain period of time has passed since the thermometer was taken out of the measurement site. Actually, the body temperature measuring circuit 5 outputs a body temperature measurement end signal Te at the time when the measured value falls below a certain temperature, and the timer control circuit 4 receiving this outputs the reset signal Rp after a certain period of time to output the timer. The signal Tm ends.

The body temperature measuring circuit 5 uses the timer signal Tm.
Is supplied, the oscillation control signal So is supplied to the temperature sensitive oscillation circuit 1, and the body temperature is measured in response to the body temperature detection signal Ts from the temperature sensitive oscillation circuit 1 to display the display signal Ds.
Is supplied to the display device 6 to display the body temperature, and when the measured value falls below a certain temperature, the body temperature measurement end signal Te
Is output and supplied to the timer control circuit 4.

Reference numeral 7 denotes a battery as a power source, and among the constituent elements of the thermometer circuit, the temperature sensitive oscillation circuit 1, the temperature change detection circuit 2 and the power supply circuit 3 are always supplied with the voltage Vd1 of the battery 3 and are spared. In the operating state, other components, that is, the timer control circuit 4, the body temperature measuring circuit 5, and the display device 6,
Normally, no voltage is supplied, and the power supply circuit 3 outputs from the time when the temperature change detection circuit 2 generates the temperature increase signal Th to the time when the timer control circuit 4 generates the reset signal Rp. It is operated by being supplied with the voltage Vd2.

FIG. 2 is a circuit diagram showing a specific configuration of the temperature change detection circuit 2 in FIG. 1, in which the thermistor Rth which is a temperature sensing element and three resistors R1, R2 and R3 have a voltage Vd1.
Is connected in series between the grounding point and the ground, and an inverter 10 for detecting the level and a pulsing circuit 11 for pulsing the output signal of the inverter 10 are connected from the midpoint P1 thereof. The pulsed temperature increase signal Th is output.

As the respective elements of the temperature change detection circuit 2, the resistors R1 and R2 are high resistances for determining the current value in the preliminary operation state, and in this embodiment, they are the same 55.
It is set to 0 KΩ. The thermistor Rth is 2 at room temperature.
50KΩ, 135K at human body temperature of 37 degrees
The resistance R3 has a temperature-sensing characteristic that changes to Ω, and the resistance R3 is a resistance for balancing the resistance change of the thermistor Rth. In the example, it is set to 150 KΩ.

That is, the operation of the temperature change detection circuit 2 is 800 KΩ when the sum of the resistance values of the thermistor Rth and the resistance R1 is 250 + 550 at room temperature, while the resistances R2 and R3.
Since the sum of the resistance values of 550 + 150 is 700 KΩ, the potential V1 at the point P1 becomes V1 <Vd1 / 2, and the inverter 10 does not generate an output signal, and therefore the temperature increase signal Th is not output.

Next, as the thermistor Rth is heated from room temperature, the resistance value of the thermistor Rth decreases, and when the resistance value becomes smaller than 150 KΩ, the potential V1 at the point P1 becomes V1> Vd1 / 2. Inverter 10 thus produces an output signal. Then, the pulsing circuit 11 pulsates this output signal and outputs it as a temperature rise signal Th.

The current value of the temperature change detection circuit 2 in the preliminary operation state is the voltage Vd1 of the battery 7 being 1, 5
If it is V, it becomes 1,5V / 1500KΩ = 1μA,
The preliminary operation state can be maintained with an extremely low current consumption.

FIG. 3 is a circuit diagram showing a specific configuration of the temperature sensitive oscillation circuit 1 and the temperature change detection circuit 2 in FIG. 1, wherein the thermistor Rth is a temperature sensitive element in the temperature sensitive oscillation circuit 1 and a temperature change detection circuit. It is also used as the temperature change detecting element in 2.

In the temperature change detection circuit 2, the thermistor Rth and the three resistors R1, R2 and R3 described in FIG. 2 are connected in series between the voltage Vd1 and the ground via the two switches SW2 and SW4. Further, in the temperature sensitive oscillation circuit 1, a reference resistor Rs and a capacitor C are connected in series between the voltage Vd1 and the ground via a switch SW1, and an inverter 12 for transmission is connected to the midpoint P2 thereof to detect a body temperature detection signal. Output Ts. Further, the thermistor Rth is connected to the midpoint P2 via two switches SW2 and SW3.

The temperature sensitive oscillation circuit 1 and the temperature change detection circuit 2
With the thermometer not used, that is, in the standby state, the switches SW2 and SW4 are ON, and the switch SW3 is OFF. In this state, the temperature change detection circuit 2 has the switches SW2 and SW4 turned ON. 2, the temperature-sensing oscillation circuit 1 is in the operating state because the switch SW3 is OFF, and the oscillation circuit is not configured and the temperature-sensitive oscillation circuit 1 is in the non-operating state.

From this standby state, the thermistor Rth
As the temperature of the thermistor Rth decreases, the temperature change detection circuit 2 outputs a temperature increase signal Th. As a result, as described with reference to FIG. 1, the temperature change detection circuit 2 receives the timer signal Tm and the temperature sensitive oscillation circuit 1
Is supplied with a timer signal Tm and an oscillation control signal So.

As a result, the temperature change detection circuit 2 becomes inactive because the switch SW4 is turned off by the timer signal Tm, and the temperature-sensitive oscillation circuit 1 becomes an oscillation circuit because the switch SW3 is turned on by the timer signal Tm. It is activated and becomes operational. The switches SW1 and SW2 are controlled by the oscillation control signal So to perform a known oscillation operation and output the body temperature measurement signal Ts.

Next, the operation of the thermometer will be described with reference to FIG. First, in the state where the thermometer is not used, that is, in the standby state, the voltage Vd1 from the battery 7 is supplied to the temperature sensitive oscillation circuit 1, the temperature change detection circuit 2, and the power supply circuit 3, but the temperature change detection circuit 2 Maintains a preliminary operation state with a small current consumption (1 μA in the present embodiment), and the other temperature-sensitive oscillation circuit 1 and the power supply circuit 3 are not operating, so that it consumes almost no current. .
Further, the timer control circuit 4, the body temperature measuring circuit 5, and the display device 6, which are supplied with the voltage Vd2 from the power supply circuit 3, are not supplied with the voltage Vd2 because the power supply circuit 3 is in a non-operating state, and are in a state in which no current is consumed. ing.

From this state, when the user sets a thermometer at the measurement site such as under the armpit or under the tongue to measure the body temperature, the thermistor Rth of the temperature change detection circuit 2 is warmed and the resistance value decreases. Then, the temperature change detection circuit 2 outputs the temperature rise signal Th. The temperature rise signal Th causes the power supply circuit 3 to be in the operating state and the voltage V
Then, d2 is output, and the timer control circuit 4, the body temperature measuring circuit 5, and the display device 6 are brought into the operating state.

Then, the timer control circuit 4 starts the timer operation and supplies the timer signal Tm to the body temperature measuring circuit 5, the temperature sensitive oscillating circuit 1 and the temperature change detecting circuit 2. As a result, the temperature-sensitive oscillation circuit 1 supplied with the oscillation control signal So from the body temperature measurement circuit 5 starts an oscillation operation and supplies the body temperature detection signal Ts to the body temperature measurement circuit 5. The body temperature measuring circuit 5 receiving the body temperature detection signal Ts measures the body temperature and displays the measured data on the display device 6.

The timer operation of the timer control circuit 4 is terminated in the state where the body temperature measuring operation is sufficiently performed, and the power supply circuit 3 is returned to the inoperative state by the reset signal Rp generated at the same time. By doing so, one body temperature measurement operation ends, and the original standby state is restored. Then, the standby state is maintained until the user sets the thermometer at the measurement site in order to measure the temperature again.

That is, the thermometer according to the present invention does not have a special power switch, but utilizes the user's body temperature measuring operation, detects a temperature rise due to the measuring operation, and turns on the power (starts the power circuit) to set the body temperature. The power is turned off (the power circuit is restored) by setting the timer for the time required for the measurement operation.

[0028]

As described above, according to the present invention, since the power switch having a mechanical structure is not provided and the power switch function is performed by the electronic circuit structure, the external operation switch has a function. The object of the present invention is to solve the problems, to realize complete waterproofing performance, to realize an electronic thermometer which does not increase the size and does not increase the price.
Further, the thermistor is also used as the temperature sensitive element in the temperature sensitive oscillation circuit, and also used as the temperature change detecting element in the temperature change detecting circuit, whereby the increase in the number of elements is further reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an electronic thermometer according to the present invention.

FIG. 2 is a circuit diagram showing a specific configuration of a temperature change detection circuit 2 in FIG.

3 is a circuit diagram showing a specific configuration of a temperature sensitive oscillator circuit 1 and a temperature change detection circuit 2 in FIG.

[Explanation of symbols]

1 Temperature sensitive oscillator 2 Temperature change detection circuit 3 power supply circuit 4 Timer control circuit 5 Body temperature measurement circuit 6 Display device Rth Thermistor Rs standard resistance

Claims (4)

[Claims] 1. An electronic thermometer having a temperature sensitive oscillation circuit having a temperature sensitive element, a power supply circuit, and a body temperature measuring circuit,
A temperature change detection circuit that detects a temperature change and outputs a temperature increase signal when the temperature reaches a predetermined temperature is provided, and the power supply circuit receives the temperature increase signal and enters a voltage output state to operate the body temperature measurement circuit. An electronic thermometer characterized by: 2. The electronic clinical thermometer according to claim 1, further comprising timer means for returning the power supply circuit in the voltage output state to the voltage non-output state after a fixed time. 3. The electronic thermometer according to claim 1, wherein the temperature change detection circuit also serves as a temperature sensitive element of the temperature sensitive oscillation circuit to detect a temperature change. 4. The electronic thermometer according to claim 3, wherein the temperature sensing element is a thermistor.