Electronic thermometer capable of rapidly measuring body temperature

Abstract

The invention discloses an electronic thermometer capable of quickly measuring body temperature. A heating source 1 with controllable temperature, a thermistor 2 for dynamically monitoring heat balance and a thermistor 3 for sensing body temperature are used in the thermometer as shown in the attached drawing to jointly form a heating and temperature measuring system, so that the body temperature can be quickly measured.

Description

Technical Field

[0001] This invention relates to the field of body temperature measurement technology, and in particular to an electronic thermometer for rapidly measuring human body temperature. Background Technology

[0002] The common method for measuring body temperature with electronic thermometers is to measure the thermistor inside the temperature sensor that comes into contact with the human body. This method is very slow, generally requiring 3 or 5 minutes or more.

[0003] Some electronic thermometers use predictive algorithms to predict actual body temperature through a short measurement period. However, since the result is not a direct measurement, the prediction results are often inaccurate due to the influence of the method of use and the environment.

[0004] Some electronic thermometers use a preheating method to speed up the measurement process. However, because the temperature of the heat source inside the sensor cannot be directly controlled, the temperature of the preheating source may exceed the body temperature, resulting in an incorrect measurement result. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a method for rapid and accurate measurement of body temperature.

[0006] The technical solution adopted in this invention is as follows: Figure 1 As shown, inside the body temperature measuring device, a temperature-measuring heat source 1, a thermistor 2 used for dynamic monitoring of thermal balance, and a thermistor 3 for sensing body temperature are used together to form a heating and temperature measurement system to achieve rapid body temperature measurement.

[0007] When the measurement begins, the device first controls the internal heating source 1 to heat up quickly to around 35 degrees Celsius, which is the lower end of the normal human body temperature range, before it comes into contact with the human body to start the temperature measurement.

[0008] Then, the internal heat source 1 is dynamically controlled to generate heat, but it must be controlled to not exceed the temperature measured by the thermistor 3 that senses body temperature. In this way, under the combined action of the internal heat source and the human body heat source, the internal and external thermal balance of the sensor is quickly achieved, thereby measuring the temperature of the thermal balance thermistor 2 and quickly obtaining the human body temperature.

[0009] Because the internal heat source is always required to be controlled below 35 degrees Celsius and the temperature monitored by the thermal balance resistor, a heat source with a temperature higher than the human body temperature will not be introduced into the temperature measurement system. Therefore, it will not affect the measurement results, but it will significantly reduce the amount of heat that needs to be transferred by the human body, thus minimizing the time required to measure body temperature.

[0010] The key feature of this invention is a temperature-controlled internal heat source, which must meet two requirements: first, the heat generation can be controlled, and second, the temperature can be measured.

[0011] This invention uses a power-type thermistor or several in parallel as an internal heat source. In practice, copper wires are laid on the printed circuit board to achieve the resistance function, which is equivalent to the heat source being directly embedded in the printed circuit board.

[0012] Power-type thermistors sense temperature by measuring their resistance. With the help of an external circuit, they can pass current or interrupt current flow, thus functioning as a temperature-controlled internal heat source. Power-type thermistors can also be used in parallel to provide greater heating power.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention allows for very rapid measurement of human body temperature, reducing the measurement time for electronic thermometers from over 3 minutes to less than 1 minute. Furthermore, because the internal heating source temperature is controllable, it does not affect measurement accuracy. The electronic thermometer made using this invention fills a market gap. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the inside of a thermometer probe. The labels in the attached diagram are explained below: 1: Temperature-measurable heat source 2: Thermistors for detecting thermal balance 3: Thermistors that sense body temperature

[0015] Figure 2 This is a circuit schematic diagram of an embodiment. The reference numerals are explained as follows: 1: Temperature-measurable heat source 2: Thermistors for detecting thermal balance 3: Thermistors that sense body temperature

[0016] Figure 3 This is the probe portion of the printed circuit board in the embodiment. The reference numerals are explained below: 1: Temperature-measurable heat source 2: Thermistors for detecting thermal balance 3: Thermistors that sense body temperature Detailed Implementation

[0017] Appendix Figure 2This is a circuit implementing the present invention. During body temperature measurement, the microcontroller controls the on / off state of the field-effect transistor Q2 via the HEAT-ON network. R3 and heat source 1 form a heating channel. Heat source 1 generates heat because current flows through it. By continuously adjusting the on / off time of Q2, the temperature of heat source 1 can be controlled. When Q2 is on, the microcontroller can measure the actual voltage of the heating channel via the HEAT-VOL-S network. In the circuit, R4 and R5 divide the voltage, and the sampled voltage is transmitted to the operational amplifier U2 via the HEAT-SN network as a reference voltage. R3 and heat source 1 divide the voltage, and the sampled voltage is transmitted to U2 via the HEAT-SP network. U2 is a differential amplifier, and resistors R7, R9, R8, and R10 determine the amplifier gain. After U2 amplifies the voltage signal, it is transmitted to the microcontroller via the HEAT-S network for conversion into the temperature of heat source 1.

[0018] The microcontroller controls the on-state of the field-effect transistor Q1 via the BAL-ON network. The power supply voltage VDD_MCU is divided by resistor R6 and the thermistor 2 for detecting thermal equilibrium, and the sampled voltage is transmitted to the microcontroller via the BAL-S network for conversion into the thermal equilibrium temperature. Similarly, the power supply voltage VDD_MCU is divided by resistor R5 and the thermistor 3 for sensing body temperature, and the sampled voltage is transmitted to the microcontroller via the SENSE-S network for conversion into the sensed body temperature. The microcontroller monitors the temperature of the thermistor 2 for thermal equilibrium. When the temperature no longer changes within a certain period of time, thermal equilibrium can be confirmed, and the thermal equilibrium temperature at this time is the measured body temperature.

[0019] Appendix Figure 3 This is the probe part of the printed circuit board in this embodiment. It can be clearly seen that the heat source 1 is composed of copper wires laid on the circuit board. In principle, this is equivalent to embedding a copper resistor inside the circuit board. This is beneficial for temperature control, and the copper resistor can also be used as a thermistor for temperature measurement. The body temperature sensing thermistor 3 is close to the edge of the probe, so that the contact distance with the thermometer probe shell is extremely short, which can quickly sense the heat transmitted from the human body. The thermal balance detection thermistor 2 is placed between 1 and 3 to facilitate monitoring of thermal balance.

Claims

1. An electronic thermometer capable of rapidly measuring body temperature, characterized in that: Inside the thermometer, a temperature-controlled heat source, a thermistor for dynamic monitoring of thermal balance, and a thermistor for sensing body temperature are used together to form a heating and temperature measurement system, enabling rapid measurement of body temperature.

2. The electronic thermometer according to claim 1, characterized in that: The internal heat source of the thermometer uses a thermistor or a parallel combination thereof that generates a large amount of heat. In practice, a copper resistor can be made by laying copper wires on a printed circuit board.

3. The electronic thermometer according to claim 1, characterized in that: The internal heating element of a thermometer uses a field-effect transistor (FET). By utilizing the proportional relationship between the conduction impedance between the drain and source of the FET and the temperature, the heating and temperature control functions are achieved.

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