CN112763070B - A kind of temperature measuring probe, non-contact infrared thermometer and temperature compensation method - Google Patents

Abstract

A temperature measuring probe includes a temperature sensor, a Fresnel lens, a copper sleeve and a pressing block; the copper sleeve includes a first chamber with a hollow cylindrical structure, and the bottom of the first chamber is provided with a concentric and inverted cup-shaped The second chamber, the outer diameter of the second chamber is smaller than the inner diameter of the copper sleeve, the bottom center of the first chamber is provided with a light-transmitting hole, the light-transmitting hole connects the first chamber and the second chamber, and the temperature sensor cooperates It is arranged in the second chamber, and the photosensitive surface of the temperature sensor and the light-transmitting hole are correspondingly arranged. The bottom of the first chamber is also provided with a first ventilation hole and a second ventilation hole which are symmetrically distributed in the center and have the same diameter. The distance from the second ventilation hole to the center of the bottom of the first chamber is equal to and greater than half of the outer diameter of the second chamber. The top is matched and connected and a circumferentially arranged groove is formed on the inner side of the connection, and the Fresnel lens is arranged in the groove.

Description

A kind of temperature measuring probe, non-contact infrared thermometer and temperature compensation method

technical field

The invention belongs to the field of infrared temperature measurement, and particularly relates to a temperature measurement probe, a non-contact infrared thermometer and a temperature compensation method.

Background technique

The non-contact infrared thermometer is an infrared receiving thermometer specially used to measure the temperature of the human body. The induced voltage is measured, and the temperature measurement value is obtained through calculation and correction.

At present, the non-contact infrared thermometers on the market can be divided into the following two types according to the principle: 1. Using the reflective cup structure, the infrared light is focused on the sensor for temperature measurement, and the distance of the temperature measurement (the temperature measurement port of the shell reaches the Human body) is usually 0 to 5 cm, and cannot be used after 5 cm; 2. Using Fresnel lens, although the temperature measurement distance (the temperature measurement port of the shell to the human body) can be effectively increased, reaching 0 to 15 cm, but in the body surface mode When the temperature is measured at a long distance, the accuracy of the test data will decrease with the increase of the distance, and the structure of this type of thermometer is complex and the processing cost is high, and the Fresnel lens is easily deformed due to sudden changes in temperature during long-term storage. , resulting in a decrease in accuracy.

SUMMARY OF THE INVENTION

The present invention provides a temperature measuring probe, a non-contact infrared thermometer and a temperature compensation method, which aims to solve the problem that the existing non-contact infrared thermometer has insufficient precision in long-distance temperature measurement and a sudden temperature change is likely to cause a decrease in accuracy. question.

To achieve the above object, the technical scheme adopted in the present invention is:

Technical solution 1: a temperature measuring probe, comprising a temperature sensor and a Fresnel lens, and characterized in that it further comprises a copper sleeve and a pressing block;

Assuming that the incident direction of infrared rays is taken as a reference, the copper sleeve includes a first chamber with a hollow cylindrical structure, the bottom of the first chamber is provided with a concentric and inverted cup-shaped second chamber, the The outer diameter of the second chamber is smaller than the inner diameter of the copper sleeve, a light-transmitting hole is provided at the bottom center of the first chamber, the light-transmitting hole communicates the first chamber and the second chamber, and the temperature The sensor is arranged in the second chamber, the photosensitive surface of the temperature sensor and the light-transmitting hole are correspondingly arranged, and the bottom of the first chamber is also provided with a first ventilation hole and a second ventilation hole which are symmetrically distributed in the center and have the same diameter. Two ventilation holes, the distances from the first ventilation hole and the second ventilation hole to the center of the bottom of the first chamber are equal and greater than half of the outer diameter of the second chamber, and the pressing block is adapted to the inner and outer diameters of the first chamber The ring structure, the pressure block is connected with the top of the first chamber and forms a circumferentially arranged groove on the inner side of the connection, the plane of the groove is parallel to the photosensitive surface of the temperature sensor, and the Fresnel lens set in the groove.

Technical solution 2: a non-contact infrared thermometer, comprising a temperature measurement probe, characterized in that: the temperature measurement probe is the temperature measurement probe described in the above solution.

Technical solution 3: The infrared thermometer according to technical solution 2 is characterized in that: it further comprises a distance sensor, and the distance sensor is arranged at the temperature measurement port of the infrared thermometer;

Assume that the focal length of the Fresnel lens is f, and 15 mm≤f≤20 mm;

Taking the use state of the infrared thermometer as a reference, the distance between the photosensitive surface of the temperature sensor and the Fresnel lens is d ₀ , and d ₀ = f±1 mm;

The distance between the Fresnel lens and the distance sensor is d ₁ , and f<d ₁ <f+5 mm.

Technical solution 4: a temperature compensation method, characterized in that: the temperature compensation method when using the non-contact infrared thermometer described in technical solution 3 to measure temperature;

The non-contact infrared thermometer adopts the body surface mode, and the optimal value T _c of the body surface temperature is calculated by the following formula:

T _c = T ₀ +K*d;

The non-contact infrared thermometer adopts the human body mode, and the human body temperature optimization value T is calculated by the following formula:

T=T _c +M= T ₀ +K*d+M;

Among them, T _c is the optimized value of body surface temperature, T is the optimized value of human body temperature, T ₀ is the actual measurement value of the temperature sensor, K is a constant, and its value range is 0°C/cm≤K≤0.2°C/cm, d is the distance in centimeters between the distance sensor and the temperature measurement source (with the infrared incident direction as a reference, more precisely, the distance between the distance sensor and the temperature measurement source projected in the infrared incident direction), the M is a constant value, And its value range is -5 ℃ ~ 5 ℃.

The relevant contents in the above technical solutions are explained as follows:

1. In the above solution, the diameters of the first ventilation hole and the second ventilation hole are 0.75 mm to 1.25 mm.

2. In the above solution, the distance sensor is an infrared distance sensor, preferably a TOF sensor. The TOF sensor measures the distance through the infrared rays reflected from the device, which is easily affected by skin color and temperature. The TOF sensor recognizes the distance by calculating the time from the emission of light waves to the reception of reflected light waves, and the skin color and temperature basically have no effect on its test accuracy. Since the distance sensor is installed at the temperature measuring port of the housing and how to use the distance sensor is in the prior art, it will not be repeated here.

3. In the above solution, the non-contact infrared thermometer may also include a start button, a control panel, a liquid crystal display, a casing, a decorative cover, a battery compartment, and a battery compartment cover.

4. In the above solution, the interior of the first chamber of the copper sleeve is preferably black to absorb astigmatism and reduce errors.

5. In the above solution, the distance sensor is arranged at the temperature measuring port of the infrared thermometer, and it should be understood that it can be arranged on the outside or inside of the shell of the temperature measuring port.

6. The specific operation method, using the non-contact thermometer, first determine the mode (body surface mode or human body mode), point the thermometer probe at the human body (recommended position is the forehead), press the measurement button, the distance sensor recognizes The distance d between the temperature measurement port and the human body is transmitted to the chip for processing. At the same time, the temperature sensor recognizes the actual measurement value T ₀ of the temperature sensor and transmits it to the chip. According to the selected mode, if it is a body surface, follow the algorithm T _c =T ₀ +K *d, the chip calculates the body surface temperature. If it is a human body model, it calculates the body temperature according to the algorithm T=T _c +M. Among them, M is a constant value, which is essentially the difference between the surface temperature and the human body temperature. It is determined according to the actual measured difference of the machine. This constant value can be input through the test at the factory, or can be set by the operator before use.

The design principle and effect of the present invention are:

⒈ The temperature measuring probe in this technical solution has a special design for the copper sleeve, and its two centrally symmetrically distributed ventilation holes can effectively prevent the lens from being deformed due to the expansion or contraction of the internal gas when the ambient temperature changes suddenly or during shipping. In addition, the number, relative position and diameter of the ventilation holes in this technical solution jointly determine the technical effect, because the ventilation holes are Increasing or increasing the number of vents will affect the temperature sensor to some extent.

⒉Analysis of Fresnel lens principle: Parallel light passes through the lens and will be focused on the focal point, so the distance between the temperature sensor photosensitive surface and the Fresnel lens in the temperature measuring probe is set to d ₀ =f±1mm. In this way, infrared rays can be collected to the greatest extent, see Figure 5;

3. On the other hand, when the distance d ₁ ≤ f between the Fresnel lens and the distance sensor (chassis temperature measurement port) (that is, when the temperature measurement source is attached to the case temperature measurement port, the temperature measurement source is far away from the Fresnel The distance of the lens is the shortest distance, and this shortest distance must be greater than the focal length of the Fresnel lens), otherwise it will not be able to image or can only form a virtual image in the same direction, so it is required that d ₁ >f (f represents the focal length) to control the human body and the Fresnel lens. The lens distance is greater than f; and in this technical solution, in order to prevent errors caused by excessive d ₁ , set d ₁ <f+5 mm, 5 mm=0.5 cm, according to the formula provided by this technical solution T _c = T ₀ +K* d, 0.1°C/cm * 0.5 cm=0.05°C, this error can be ignored, see Figure 6-7.

4. This technical solution also limits the focal length of the Fresnel lens, the distance between the temperature sensor and the Fresnel lens, and the distance between the Fresnel lens and the temperature measuring port of the housing, so that the distance can be measured by a linear formula. Temperature compensation for distance temperature measurement increases the accuracy of non-contact infrared thermometers in remote temperature measurement.

5. This technical solution combines the distance compensation temperature measurement method with the Fresnel lens technology. First, by designing the copper sleeve structure, selecting the appropriate Fresnel lens, and setting the distance parameters between the lens and the infrared temperature sensor, a measurement probe is formed. The probe makes the relationship between the measurement value and the distance a linear function. After identifying the detailed distance through the distance sensor, the algorithm is used to add the distance to the temperature measurement compensation, so that as the distance increases, the compensation is performed synchronously to improve the measurement accuracy.

6. This technical solution provides a long-distance accurate temperature measurement infrared non-contact temperature measurement device to meet the demand for accurate measurement of long-distance non-contact thermometers in the market. This technology not only improves the measurement accuracy and measurement efficiency, but also effectively protects the measurement. (during the epidemic, the distance is required to be 1m).

Description of drawings

Accompanying drawing 1 is the exploded view of the temperature measuring probe of the present invention;

Accompanying drawing 2 is the copper sleeve cross-sectional sectional view of the present invention;

3 is a cross-sectional sectional view of the temperature measuring probe of the present invention;

4 is a cross-sectional view of the infrared thermometer of the present invention;

Accompanying drawing 5 is the principle diagram of parallel light incident Fresnel penetration;

Figure 6 is a schematic diagram showing that light cannot be imaged on a Fresnel lens.

In the above drawings: 1. temperature sensor; 2. Fresnel lens; 3. Copper sleeve; 31. First chamber; 311. Light transmission hole; 312. First ventilation hole; 313. Second ventilation hole; 32. Second chamber; Groove; 4. Press block; 5. Sensor; 6. Infrared.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention is further described:

Embodiment 1: a temperature measuring probe

As shown in Figure 1-3, a temperature measuring probe includes a temperature sensor 1, a Fresnel lens 2, a copper sleeve 3, and a pressing block 4;

Assuming that the incident direction of the infrared rays 6 is taken as a reference, the copper sleeve 3 includes a first chamber 31 with a hollow cylindrical structure, and the bottom of the first chamber 31 is provided with a concentric and inverted cup-shaped second chamber chamber 32, the outer diameter of the second chamber 32 is smaller than the inner diameter of the copper sleeve 3, a light-transmitting hole 311 is provided at the bottom center of the first chamber 31, and the light-transmitting hole 311 communicates with the first chamber chamber 31 and the second chamber 32, the temperature sensor 1 is arranged in the second chamber 32, the photosensitive surface of the temperature sensor 1 and the light-transmitting hole 311 are correspondingly arranged, the first chamber 31 The bottom is also provided with a first ventilation hole 312 and a second ventilation hole 313 which are symmetrically distributed in the center and have the same diameter. Half of the outer diameter of the second chamber 32 , the pressing block 4 is a ring-shaped structure whose inner and outer diameters are adapted to the first chamber 31 , the pressing block 4 is connected with the top of the first chamber 31 and is on the inner side of the connection. Circumferential grooves 33 are formed. The plane of the grooves 33 is parallel to the photosensitive surface of the temperature sensor 1 . The Fresnel lens 2 is arranged in the grooves 33 . The diameter of the first ventilation hole 312 and the second ventilation hole 313 is 1 mm.

Embodiment 2: A non-contact infrared thermometer, including a temperature measurement probe: the temperature measurement probe is the temperature measurement probe described in Embodiment 1, and also includes a distance sensor 5, which is arranged in the The temperature measuring port of the infrared thermometer;

The focal length of Fresnel lens 2 is 20 mm;

Taking the use state of the infrared thermometer as a reference, the distance between the photosensitive surface of the temperature sensor 1 and the Fresnel lens 2 is d ₀ , and d ₀ =20 mm;

The distance between the Fresnel lens 2 and the distance sensor 5 is d ₁ , and d ₁ =21 mm.

Embodiment 3: a temperature compensation method, it is characterized in that: for the non-contact infrared thermometer in embodiment 2 to carry out temperature compensation method;

The non-contact infrared thermometer adopts the body surface mode, and the optimal value T _c of the body surface temperature is calculated by the following formula:

T _c = T ₀ +K*d;

The non-contact infrared thermometer adopts the human body mode, and the human body temperature optimization value T is calculated by the following formula:

T=T _c +M= T ₀ +K*d+M;

Wherein, T _c is the body surface temperature optimization value, T is the human body temperature optimization value, T ₀ is the actual measurement value of the temperature sensor, in this embodiment, K is 0.1 ℃/cm, d is the distance between the sensor and the temperature measurement source. The distance in centimeters, the M is a constant value, which is the difference between the values displayed by the temperature sensor when using the human body mode and the body surface mode respectively when measuring the temperature of the same test source. The following table 1 is the measured value and the optimized value obtained by the temperature sensor of Example 2 (that is, the copper sleeve is provided with two ventilation holes): The following table 2 is the temperature sensor test of Example 2 after being placed at 16°C for a week Data and calculation data; Table 3 below is the temperature sensor test data and calculation data of Example 2 after being placed at 39°C for one week;

Table 1:

Table 2: One week at 16°C

Table 3: 39℃ for one week

According to Table 1-3, through the design of two ventilation holes on the copper sleeve, the error caused by the temperature measurement distance can be well compensated by the formula of T _c = T ₀ +K*d, and the consistency of the temperature measurement data can be ensured. And after being placed in the environment of 16 ℃ and 39 ℃ for a week, the temperature measurement data is still consistent.

Comparative Example 1: The copper sleeve in Example 2 was replaced with a non-porous copper sleeve, and temperature was measured. The following table 4 (that is, the copper sleeve has no ventilation holes) is the value measured by the temperature sensor and the value after being placed at 39 ° C for one week.

Table 4:

Comparative Example 2: The copper sleeve in Example 2 was replaced with a copper sleeve with 4 ventilation holes, and the temperature was measured. The following table 5 (that is, the copper sleeve has 4 ventilation holes) is the value measured by the temperature sensor and the value after being placed at 39 ℃ for one week.

table 5:

d (cm) <i>0</i> <i>1</i> <i>2</i> <i>3</i> <i>4</i> <i>5</i> <i>6</i> <i>7</i> <i>8</i> <i>9</i> <i>10</i> T₀ 40.2 40.0 39.8 39.7 39.7 39.5 39.3 39.2 39.1 39.0 38.9 T₀^’ 40.3 40.0 39.9 39.8 39.3 39.3 39.2 39.0 39.0 38.9 38.7

Comparing Table 4 and Table 5, in the case of a copper sleeve without ventilation holes or with 4 ventilation holes, the linear fitting effect of the data consistency measured by the temperature sensor is not good, and the consistency of the data is also slightly worse.

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (4)

1. The utility model provides a temperature probe, includes temperature sensor (1), fresnel lens (2), its characterized in that: the copper sleeve is also provided with a copper sleeve (3) and a pressing block (4);

use the incident direction of infrared ray (6) as the reference, copper sheathing (3) are including a first cavity (31) of hollow tubular structure, the bottom of first cavity (31) is equipped with a concentric and cup-shaped second cavity (32) of inversion, the external diameter of second cavity (32) is less than the internal diameter of copper sheathing (3), the bottom center department of first cavity (31) is equipped with a light trap (311), light trap (311) intercommunication first cavity (31) and second cavity (32), temperature sensor (1) cooperation set up in second cavity (32), the sensitization face and the light trap (311) of temperature sensor (1) correspond the setting, the bottom of first cavity (31) still is equipped with central symmetry distribution and the equal first ventilation hole (312) and the second ventilation hole (313) of diameter, first ventilation hole (312) and second ventilation hole (313) are equal and all are greater than the second ventilation hole (313) to the equal distance in first cavity (31) bottom center The pressure block (4) is of an annular structure with the inner diameter and the outer diameter matched with the first cavity (31), the pressure block (4) is connected with the top of the first cavity (31) in a matched mode, a groove (33) arranged in the circumferential direction is formed in the inner side of the connection position, the plane where the groove (33) is located is parallel to the light-sensitive surface of the temperature sensor (1), and the Fresnel lens (2) is arranged in the groove (33);

the diameters of the first vent hole (312) and the second vent hole (313) are 0.75 mm-1.25 mm.

2. The utility model provides a non-contact infrared thermometer, includes temperature probe, its characterized in that: the temperature probe is the temperature probe of claim 1.

3. The non-contact infrared thermometer of claim 2 wherein: the infrared thermometer is characterized by further comprising a distance sensor (5), wherein the distance sensor (5) is arranged at a temperature measuring port of the infrared thermometer;

the focal length of the Fresnel lens (2) is f, and f is more than or equal to 15 mm and less than or equal to 20 mm;

the using state of the infrared thermometer is taken as reference, and the distance between the light sensing surface of the temperature sensor (1) and the Fresnel lens (2) is d₀And d is₀= f±1 mm；

The distance between the Fresnel lens (2) and the distance sensor (5) is d₁And f < d₁＜f+5 mm。

4. A method of temperature compensation, comprising: a temperature compensation method in measuring temperature using the non-contact infrared thermometer according to claim 3;

the non-contact infrared thermometer adopts the optimized value T of the body surface temperature in the body surface mode_cCalculated by the following formula:

T_c= T₀+K*d；

the non-contact infrared thermometer is in a human body mode, and the human body temperature optimized value T is calculated by the following formula:

T=T_c+M= T₀+K*d+M;

wherein, T_cFor an optimum value of the body surface temperature, T being an optimum value of the human body temperature, T₀K is a constant and is equal to or less than 0 ℃/cm and equal to or less than 0.2 ℃/cm, d is the distance centimeter between the distance sensor and the temperature measurement source, M is a constant and is equal to or less than-5 ℃.

Images