An infrared thermometer

Abstract

The present application relates to an infrared thermometer, which can automatically switch between ear temperature measurement mode and forehead temperature measurement mode, including: a housing, a switch and a measurement button arranged on the housing, a display screen, an ear temperature measurement column, an infrared sensor arranged on the ear temperature measurement column, and a control circuit arranged inside the housing, the infrared thermometer also includes a temperature sensing head cover and a filter arranged on the temperature sensing head cover, the infrared thermometer directly measures ear temperature through the ear temperature measurement column, and when measuring forehead temperature, the temperature sensing head cover is connected with the ear temperature measurement column. The infrared thermometer does not need to add additional button control, and can automatically switch to the forehead temperature measurement mode through the infrared AD value received by the thermopile, which simplifies the structural design and reduces the cost.

Description

Technical Field

[0001] The present application belongs to the technical field of body temperature measurement, and specifically relates to an infrared thermometer capable of automatically selecting a forehead temperature mode or an ear temperature mode. Background Art

[0002] Body temperature is an important indicator of human health. Thermometers are essential for daily household use and basic medical instruments in clinical medicine. Traditional mercury thermometers have become the most widely used body temperature measurement tools with relatively stable performance and accurate measurement results. However, the reading of mercury thermometers is inconvenient and fragile. The exposed mercury is harmful to human health and causes environmental pollution. With the continuous development of science and technology, infrared human body temperature measurement technology has been widely used. It meets people's requirements for modern body temperature measurement with shorter response time, higher measurement accuracy and accuracy.

[0003] Infrared human body temperature measurement technology receives infrared radiation from the human body through an infrared sensor, and obtains the human body temperature after processing by the temperature measurement circuit module. Infrared thermometers include contact ear cavity infrared thermometers and non-contact forehead infrared thermometers. Ear cavity thermometers are accurate, fast, and convenient, but due to contact measurement, they need to be disinfected or replaced with protective covers when used by multiple people, which increases costs and wastes resources. Non-contact infrared thermometers only need to point the probe at the forehead and get the measurement data after a few seconds. However, forehead infrared thermometers have many disadvantages such as interference from infrared radiation, great influence of ambient temperature, and users are not familiar with the operation method, so the measurement may produce large errors.

[0004] Since the modes and algorithms for measuring forehead temperature and ear temperature are different, and the environmental factors and interferences considered are also different, different modes and different algorithms are required, so it is necessary to set the measurement mode during measurement, including forehead temperature mode and ear temperature mode. The existing infrared thermometer selects the mode by installing different temperature probe covers and triggering the corresponding switch, such as the patent (US patent number: 0047392A1, Mar. 11, 2004) installing a probe cover when measuring forehead temperature to trigger the forehead temperature mode switch. The patent (US patent number: 6789936B1, Sep. 14, 2014) installs a forehead temperature probe cover to trigger the forehead temperature measurement mode switch. Another patent application publication number CN107817051A selects whether to install a forehead temperature test head cover when measuring different parts, and manually selects the mode by selecting the button on the thermometer body. The above method requires additional sensors, complex structural design, high defect rate, and high cost, and sometimes the manual selection forgets to select the mode, resulting in inaccurate measurement. In the existing technology, the probe cover installed when measuring ear temperature or forehead temperature uses a through hole, and the infrared radiation signal intensity received by the infrared sensor probe is directly emitted from the human body surface. Summary of the invention

[0005] In view of the shortcomings of the above two products, the purpose of the present invention is to provide an infrared thermometer that can be used to measure ear temperature and forehead temperature at the same time. The present invention adds a transmission sheet to the forehead temperature probe cover, and automatically identifies the forehead temperature mode or ear temperature mode according to the intensity of the infrared signal received by the infrared sensor.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] An infrared thermometer capable of automatically switching between an ear temperature measurement mode and a forehead temperature measurement mode, comprising: a shell, a switch and a measurement button arranged on the shell, a display screen, an ear temperature measurement column, an infrared sensor arranged on the ear temperature measurement column, and a control circuit arranged inside the shell. The infrared thermometer also comprises a temperature sensing head cover and a filter arranged on the temperature sensing head cover. The infrared thermometer directly measures ear temperature through the ear temperature measurement column. When measuring forehead temperature, the temperature sensing head cover is cooperatively connected with the ear temperature measurement column.

[0008] The purpose of the present invention can be further achieved by the following technical solutions:

[0009] Preferably, the filter covers the sensing range of the infrared sensor.

[0010] Preferably, the filter is a silicon flat plate, using single crystal silicon as a substrate, and a high infrared transmission optical film is evaporated on the surface of the single crystal silicon.

[0011] Preferably, the shell is composed of a front panel and a back panel, and the switch and the measuring button are arranged in the middle of the front panel of the shell, and the switch and the measuring button are used to turn on the infrared thermometer and start the measurement program to measure the target temperature.

[0012] More preferably, a setting button for querying historical records is also provided on the front panel.

[0013] Preferably, the display screen is LED and is arranged on the upper part of the front panel.

[0014] Preferably, a battery compartment and a battery back cover are provided on the back panel.

[0015] Preferably, the infrared sensor is composed of a filter, a thermopile and a thermistor.

[0016] More preferably, the control circuit includes an amplifying circuit, a converting circuit, a main control circuit, a display circuit and an alarm circuit.

[0017] More preferably, the thermopile of the infrared sensor is connected to the amplifier circuit, the thermistor and the amplifier circuit are respectively connected to the conversion circuit, the conversion circuit is connected to the main control circuit, and the main control circuit is connected to the display circuit and the alarm circuit.

[0018] More preferably, the conversion circuit is an AD conversion circuit.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] The infrared thermometer of the present invention adds a forehead temperature measuring head with a filter on the temperature sensing head cover. When measuring forehead temperature, there is no need to add additional button control. The infrared AD value received by the thermopile can automatically switch to the forehead temperature measurement mode, which simplifies the structural design and reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the infrared thermometer of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the infrared thermometer of the present invention in the forehead temperature measurement mode.

[0023] Among them: 1. Shell; 2. Switch and measurement button; 3. Setting button; 4. Display screen; 5. Temperature sensing head cover; 6. Filter; 7. Infrared sensor; 8. Ear temperature measurement column; 9. Back panel; 10. Control circuit; 11. Battery back cover; 12. Battery; 13. Front panel. DETAILED DESCRIPTION

[0024] The present invention provides an infrared thermometer which can automatically switch between an ear temperature measurement mode and a forehead temperature measurement mode. Figure 1 As shown, it includes: a shell 1, a switch and a measuring button 2 arranged on the shell 1, a display screen 4, an ear temperature measuring column 8 protruding from the shell 1, an infrared sensor 7 arranged at the far end of the ear temperature measuring column 8 and a control circuit 10 arranged inside the shell 1. The infrared thermometer of the present invention also includes a temperature sensing head cover 5 and a filter 6 arranged on the temperature sensing head cover 5. The infrared thermometer directly measures the ear temperature through the ear temperature measuring column 8. When measuring the forehead temperature, the temperature sensing head cover 5 is connected with the ear temperature measuring column 8.

[0025] The filter 6 covers the sensing range of the infrared sensor 7. The filter 6 is a silicon flat sheet, using single crystal silicon as a substrate, and a high infrared transmission optical film is evaporated on the surface of the single crystal silicon. In a preferred embodiment, the filter 6 uses CMOS-grade single crystal silicon as a substrate.

[0026] The housing 1 is composed of a front panel 13 and a back panel 9. A switch and a measuring button 2 are arranged in the middle of the front panel 13 of the housing 1. The switch and the measuring button 2 are used to turn on the infrared thermometer and start the measurement program to measure the target temperature. A setting button 3 for querying historical records is also arranged on the front panel 13. An LED display screen 4 is arranged on the upper part of the front panel 13. A battery compartment 12 and a battery rear cover 11 are arranged on the back panel 9. In a preferred embodiment, the ear temperature measuring column 8 is arranged on the top of the housing 1.

[0027] The infrared sensor 7 is composed of a filter, a thermopile (VTP) and a thermistor (NTC). The control circuit 10 includes an amplifier circuit, a conversion circuit, a main control circuit (MCU), a display circuit and an alarm circuit. The filter adopts a filter commonly used in ear temperature detection devices, preferably a single crystal silicon flat plate. The conversion circuit is preferably an AD conversion circuit. The thermopile end of the infrared sensor 7 is connected to the amplifier circuit, the thermistor end of the infrared temperature sensor and the amplifier circuit are respectively connected to the AD conversion circuit, the AD conversion circuit is connected to the main control circuit (MCU), and the main control circuit is connected to the display circuit and the alarm circuit.

[0028] When the infrared rays emitted by the forehead or eardrum of the human body pass through the infrared sensor 7, the filter of the infrared sensor 7 will automatically filter out the remaining wavelengths outside the infrared range.

[0029] The thermopile of the infrared sensor is composed of a large number of thermocouples connected in series. The thermocouple is composed of a thermocouple junction and a reference junction. The infrared rays input through the filter of the infrared sensor are absorbed by the thermocouple junction to generate heat to heat up the thermocouple junction itself. The temperature of the reference junction is measured by the thermistor. The temperature difference between the thermocouple junction and the reference junction generates a thermoelectric electromotive force. The thermoelectric electromotive forces generated by a large number of thermocouples are connected in series to form a thermopile electromotive force output; the voltage signal is amplified by the amplifier and converted by the digital-to-analog conversion circuit, and then input into the main control circuit (MCU), and the temperature difference ΔT between the target object temperature and the ambient temperature is obtained by calculation or table lookup. The main control circuit (MCU) collects the resistance value of the thermistor (NTC) and determines the ambient temperature Tamb by looking up the temperature-resistance table; the main control circuit (MCU) adds the temperature difference result ΔT between the target temperature and the ambient temperature and the ambient temperature result Tamb to obtain the target temperature Tobj:

[0030] Tobj=Tamb+ΔT.

[0031] When the infrared thermometer of the present invention adopts the ear temperature measurement mode, the ear temperature measurement column 8 can be inserted into the patient's ear canal to directly measure the temperature. The infrared sensor 7 arranged in the ear temperature measurement column 8 directly obtains the infrared rays emitted by the eardrum, and the ear temperature mode clinical algorithm compensation is performed to obtain the required temperature value.

[0032] like Figure 2 As shown, when the infrared thermometer of the present invention adopts the forehead temperature measurement mode, the temperature sensing head cover 5 needs to be covered on the ear temperature measurement column 8. Since the temperature sensing head cover 5 is equipped with a filter 6, the infrared rays emitted from the forehead pass through the filter 6 set on the top of the temperature sensing head cover 5 and then enter the infrared sensor. Different measurement modes are identified by using the different AD values ​​of the thermopile with and without the filter.

[0033] This application conducted multiple experiments and measured the thermopile AD value data from 32°C to 42.0°C. The measurement results are shown in the following table:

[0034]

[0035]

[0036] From the above data, it can be seen that the maximum AD value after adding the filter is about 1000, and the minimum AD value without adding the filter is about 900. However, in reality, the human forehead temperature does not reach 32°C, and the lowest temperature of the human ear temperature is generally around 34°C, so the threshold of the present invention uses 1200 as the dividing line. During measurement, when the thermopile AD value is less than 1200, the forehead temperature measurement mode is triggered, and the forehead temperature clinical algorithm compensation is performed in the main control circuit (MCU). The forehead temperature clinical algorithm compensation after adding the filter first ensures that the blackbody temperature measurement error value of the forehead temperature after adding the filter is within ±0.2°C, and then fits the forehead temperature clinical algorithm compensation based on a large amount of human forehead temperature clinical data.

[0037] During the production process of infrared thermometers, the thermometers need to be calibrated. The so-called calibration is to calibrate the thermometer with the standard black body temperature (37°C). When calibrating the infrared thermometer of the present invention, two temperature points are selected, one is the ambient temperature (25°C), and the other is the standard black body temperature (37°C) under the ambient temperature of 25°C. Two calibration methods can usually be used for calibration, namely, water tank calibration and standard resistance calibration. The specific calibration process is as follows:

[0038] 1. The method of calibrating the ambient temperature (25℃) is as follows: adjust the water tank temperature to 25℃, put the sensor in a waterproof jacket and soak it in water for more than 5 minutes, and then calibrate the 25℃ ambient temperature. Generally, we use thermistors to calibrate the ambient temperature. The resistance value of the 25℃ ambient temperature is 100kΩ, so when calibrating the standard resistor, you can directly connect a 100kΩ standard resistor in series for calibration;

[0039] 2. The method for calibrating the blackbody temperature (37°C) is as follows: first store the infrared thermometer in a 25°C environment for more than one hour to make the ambient temperature of the sensor consistent with the actual ambient temperature, and then calibrate and measure the 37°C blackbody temperature;

[0040] 3. Measure the black body temperature value of 32°C-41°C under the ambient temperature of 15°C-35°C to verify the temperature accuracy of the infrared thermometer of the present invention.

[0041] Because the signal strength detected by the infrared sensor 7 is different depending on whether the filter 6 is set on the temperature sensing head cover 5, it is necessary to calibrate the two modes of setting the filter and not setting the filter respectively. Then, during the production process, black body compensation is performed separately to ensure accurate black body measurement.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An infrared thermometer, comprising: The invention relates to a housing (1), a switch and a measuring button (2) arranged on the housing (1), a display screen (4), an ear temperature measuring column (8), an infrared sensor (7) arranged in the ear temperature measuring column (8), and a control circuit (10) arranged inside the housing (1), characterized in that it also includes a temperature sensing head cover (5) and a filter (6) arranged on the temperature sensing head cover (5), wherein the infrared thermometer directly measures the ear temperature through the ear temperature measuring column (8), and when measuring the forehead temperature, the temperature sensing head cover (5) is connected with the ear temperature measuring column (8), and the infrared rays emitted from the forehead pass through the filter (6) arranged at the top of the temperature sensing head cover (5) and then enter the infrared sensor (7), and the infrared thermometer automatically identifies and switches between the ear temperature measurement mode and the forehead temperature measurement mode by using the different AD values ​​of the thermopile with and without the filter.

2. The infrared thermometer according to claim 1, characterized in that: The optical filter (6) covers the sensing range of the infrared sensor (7).

3. The infrared thermometer according to claim 1, characterized in that: The optical filter (6) is a silicon flat plate, using single crystal silicon as a substrate, and a high infrared transmission optical film is evaporated on the surface of the single crystal silicon.

4. The infrared thermometer according to claim 1, characterized in that: The housing (1) is composed of a front panel (13) and a back panel (9), and the switch and measuring button (2) are arranged in the middle of the front panel (13) of the housing (1). The switch and measuring button (2) are used to turn on the infrared thermometer and start a measurement program to measure the target temperature.

5. The infrared thermometer according to claim 4, characterized in that: A setting button (3) for querying historical records is also provided on the front panel (13).

6. The infrared thermometer according to claim 4, characterized in that: A battery compartment (12) and a battery rear cover (11) are provided on the back panel (9).

7. The infrared thermometer according to claim 1, characterized in that: The infrared sensor (7) is composed of a filter, a thermopile and a thermistor.

8. The infrared thermometer according to claim 7, characterized in that: The control circuit (10) comprises an amplifying circuit, a converting circuit, a main control circuit, a display circuit and an alarm circuit.

9. The infrared thermometer according to claim 8, characterized in that: The thermopile of the infrared sensor (7) is connected to the amplifier circuit, the thermistor and the amplifier circuit are respectively connected to the conversion circuit, the conversion circuit is connected to the main control circuit, and the main control circuit is connected to the display circuit and the alarm circuit.

Images