Dichroic radiation thermometer, laser system, and temperature measuring method

Abstract

To provide a two color radiation thermometer or the like capable of measuring the temperature of an object with high accuracy.SOLUTION: The two color radiation thermometer 1 includes the first sensor 10 configured to detect the first intensity that is the intensity of the first infrared ray IR1 radiated by the subject S, and the second sensor 20 configured to detect the second intensity that is the intensity of the second infrared ray IR1 radiated by the subject S and having the wave length different from the wave length of the first infrared ray IR2. And a temperature calculation unit 30 that calculates a temperature of the object S on the basis of an intensity ratio, which is a ratio between the first intensity detected by the first sensor 10 and the second intensity detected by the second sensor 20, and the calculated coefficient A. The correction function is calculated by correction coefficients α and β calculated in advance from an actually measured temperature of each of a plurality of different materials.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a two-color radiation thermometer, a laser system using the two-color radiation thermometer, and a temperature measurement method. [Background technology]

[0002] There is a known technology for measuring the temperature of an object based on the infrared radiation emitted by the object. In this case, if the temperature of the object is calculated from only the intensity of infrared radiation of one wavelength, the emissivity of the object is required. Two-color radiation thermometers, which calculate the temperature of an object from the intensity ratio of two infrared rays of different wavelengths emitted by the object, are known not to require the emissivity of the object in principle. However, errors can occur in the temperature calculated by two-color radiation thermometers. Specifically, for gray bodies, the emissivity is constant and less than 1, regardless of wavelength, but for general materials (such as metals), the emissivity tends to decrease as the wavelength becomes longer. For this reason, two-color radiation thermometers, which use the ratio of two wavelengths, can produce errors.

[0003] As an example of this type of two-color radiation thermometer, Patent Document 1 discloses a temperature measurement module including a first infrared sensor that measures infrared rays emitted by an object to be measured, a second infrared sensor that measures infrared rays in a wavelength range longer than the wavelength range measured by the first infrared sensor, a first temperature detection means that detects the temperature of the object to be measured based on the intensity ratio between the infrared rays measured by the first infrared sensor and the infrared rays measured by the second infrared sensor, a second temperature detection means that detects the temperature of the object to be measured based on the intensity of the infrared rays measured by the second infrared sensor, and a comparison means that compares the temperature data output by the first temperature detection means with the temperature data output by the second temperature detection means and outputs the higher temperature data. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-10421 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the temperature of an object to be measured is calculated solely from the intensity ratio of two infrared rays with different wavelengths, differences in the characteristics of the object (material) can lead to errors in the temperature. Moreover, the measurement error itself varies depending on the conditions (distance, wavelength, etc.). In other words, even if a temperature that is thought to have a smaller error (i.e., the higher temperature) is adopted, as in the method disclosed in Patent Document 1, it is not possible to eliminate potential errors due to differences in material characteristics.

[0006] As mentioned above, for gray bodies, the emissivity is constant regardless of wavelength, so the intensity ratio of two infrared rays with different wavelengths is also constant. However, for metals, the emissivity decreases as the wavelength increases, and the wavelength dependency of emissivity varies depending on the type of metal. Therefore, the intensity ratio of two infrared rays with different wavelengths varies depending on the combination of the two infrared rays or the type of metal. This results in errors in the calculated temperature.

[0007] The present disclosure is intended to solve such problems, and aims to provide a two-color radiation thermometer, a laser system, and a temperature measurement method that can measure the temperature of an object with high accuracy. [Means for solving the problem]

[0008] In order to achieve the above object, the two-color radiation thermometer according to the present disclosure includes: a first sensor that detects a first intensity, which is the intensity of a first infrared ray radiated by an object; a second sensor that detects a second intensity, which is the intensity of a second infrared ray radiated by the object and has a wavelength different from the wavelength of the first infrared ray; and a temperature calculation unit that calculates a first coefficient by inputting a second coefficient calculated from the first intensity detected by the first sensor and the second intensity detected by the second sensor into a correction function, and calculates the temperature of the object based on the calculated first coefficient and an intensity ratio, which is the ratio between the first intensity detected by the first sensor and the second intensity detected by the second sensor, wherein the correction function is calculated using a first correction coefficient calculated in advance from the actual measured temperatures of each of a plurality of different materials and a second correction coefficient calculated in advance from the actual measured temperatures of each of the plurality of different materials.

[0009] A laser system according to the present disclosure includes a laser device that outputs laser light to be irradiated onto an object, and the above-described two-color radiation thermometer, wherein the two-color radiation thermometer measures the temperature of the object.

[0010] Furthermore, a temperature measurement method according to the present disclosure is a measurement method for measuring the temperature of an object that emits a first infrared ray and a second infrared ray having a wavelength different from that of the first infrared ray, the method comprising: calculating a first coefficient by inputting a second coefficient calculated from a first intensity, which is the intensity of the first infrared ray detected by a first sensor, and a second intensity, which is the second intensity, of the second infrared ray detected by a second sensor, into a correction function; calculating the temperature of the object based on the calculated first coefficient and an intensity ratio, which is the ratio between the first intensity detected by the first sensor and the second intensity detected by the second sensor; and calculating the correction function using a first correction coefficient calculated in advance from the actual measured temperature of each of a plurality of different materials and a second correction coefficient calculated in advance from the actual measured temperature of each of the plurality of different materials. [Effects of the Invention]

[0011] According to the present disclosure, the temperature of an object can be measured with high accuracy. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a configuration of a laser system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the relationship between the intensity ratio of two infrared rays emitted from a black body and the temperature. [Figure 3] FIG. 3 is a diagram showing the relationship between the intensities of two infrared rays emitted from the materials used in FIG. [Figure 4A] FIG. 4A is a graph showing the relationship between the intensity ratio of two infrared rays and temperature for material a. [Figure 4B] FIG. 4B is a graph showing the relationship between the intensity ratio of two infrared rays and temperature for material b. [Figure 4C] FIG. 4C is a graph showing the relationship between the intensity ratio of two infrared rays and temperature for material c. [Figure 5A] FIG. 5A is a diagram showing the relationship between the intensities of two infrared rays for material a. [Figure 5B] FIG. 5B is a diagram showing the relationship between the intensities of the two infrared rays for material b. [Figure 5C] FIG. 5C is a diagram showing the relationship between the intensities of the two infrared rays for material c. [Figure 6] FIG. 6 is a diagram showing α when α is constant regardless of the value of β. [Figure 7] FIG. 7 is a diagram showing a correction function obtained by approximating a plurality of combinations of the correction coefficients α and β with a quadratic function. [Figure 8] FIG. 8 is a diagram showing the relationship between the calculated temperature and the actually measured temperature when α is constant. [Figure 9] FIG. 9 is a diagram showing the relationship between the calculated temperature and the actually measured temperature when the correction function is a quadratic function. [Figure 10] FIG. 10 is a diagram showing the relationship between the intensity ratio of two infrared rays with a different wavelength combination from that in FIG. 2 and the temperature. [Figure 11] FIG. 12 is a diagram showing the relationship between the intensities of two infrared rays emitted from the materials used in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Specific embodiments of the present disclosure will be described below with reference to the drawings. Note that the embodiments described below all represent a comprehensive or specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, component placement and connection configurations, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0014] Furthermore, each drawing is a schematic diagram and is not necessarily a precise illustration. In each drawing, substantially the same components are denoted by the same reference numerals, and redundant explanations will be omitted or simplified.

[0015] (Embodiment) First, the configuration of a laser system 100 according to the embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of a laser system 100 according to the embodiment.

[0016] As shown in FIG. 1, the laser system 100 includes a two-color radiation thermometer 1 that measures the temperature of an object S, and a laser device 2 that outputs laser light La to be irradiated onto the object S.

[0017] The two-color radiation thermometer 1 is a two-color radiation thermometer that measures temperature by detecting two infrared rays with different wavelengths. In the laser system 100, the two-color radiation thermometer 1 measures the temperature of the object S when irradiating the object S with laser light. In other words, the object S is a measurement object whose temperature is measured by the two-color radiation thermometer 1.

[0018] The two-color radiation thermometer 1 includes a first sensor 10 and a second sensor 20 that detect infrared rays, and a temperature calculation unit 30.

[0019] The first sensor 10 is an infrared sensor that detects a first intensity, which is the intensity of a first infrared ray IR1 emitted by the object S. The first infrared ray IR1 (solid line in FIG. 1) emitted by the object S passes through a first wavelength-selective filter M1, is reflected by a second wavelength-selective filter M2, is reflected by a third wavelength-selective filter M3, and is incident on the first sensor 10. As an example, the second wavelength-selective filter M2 and the third wavelength-selective filter M3 are long-pass filters (LPFs).

[0020] The wavelength range of the first infrared ray IR1 detected by the first sensor 10 is, for example, 0.9 μm to 2.55 μm. The first sensor 10 is, for example, a photodiode that can detect the intensity of infrared rays. In this case, the first sensor 10 can detect the intensity of infrared rays as a voltage value. In this embodiment, an InGaAs PIN photodiode is used as the first sensor 10. However, the first sensor 10 is not limited to a photodiode. For example, the first sensor 10 may be another sensor such as a thermopile-type infrared sensor.

[0021] The second sensor 20 is an infrared sensor that detects a second intensity, which is the intensity of the second infrared ray IR2 emitted by the object S. The wavelength λ2 of the second infrared ray IR2 is different from the wavelength λ1 of the first infrared ray IR1 (λ1 ≠ λ2). In this embodiment, the wavelength λ2 of the second infrared ray IR2 detected by the second sensor 20 is longer than the wavelength λ1 of the first infrared ray IR1 detected by the first sensor 10 (λ2 > λ1). The second infrared ray IR2 (dashed line in FIG. 1) emitted by the object S passes through the first wavelength-selecting filter M1, is reflected by the second wavelength-selecting filter M2, passes through the third wavelength-selecting filter M3, and is incident on the second sensor 20.

[0022] The wavelength range of the second infrared ray IR2 detected by the second sensor 20 is, for example, 2 μm to 5 μm. The second sensor 20 is, for example, an InAsSb photovoltaic element capable of detecting infrared rays. In this case, the second sensor 20 can detect the intensity of the infrared rays as a voltage value. However, the second sensor 20 is not limited to an InAsSb photovoltaic element.

[0023] The temperature calculation unit 30 calculates the temperature of the object S based on the first intensity of the first infrared ray IR1 detected by the first sensor 10 and the second intensity of the second infrared ray IR2 detected by the second sensor 20. Specifically, the temperature calculation unit 30 calculates the temperature of the object S using a correction function. Details of the temperature calculation method in the temperature calculation unit 30 will be described later. The temperature calculation unit 30 is configured with a processor (CPU), a memory, a circuit, etc.

[0024] The laser device 2 is, for example, a laser oscillator and includes a semiconductor laser element that emits laser light. When a predetermined power is input to the semiconductor laser element, the laser device 2 outputs laser light La of a predetermined wavelength. The laser light La emitted from the laser device 2 is reflected by a first wavelength selection filter M1 and irradiated onto the target S. In this embodiment, the laser device 2 and the two-color radiation thermometer 1 are optically arranged coaxially.

[0025] The laser system 100 is also configured to be able to observe the object S. Specifically, the laser system 100 is equipped with an observation camera having an image sensor 3 that can capture visible light. Visible light Lb (dash-dotted line in FIG. 1) around the object S passes through the first wavelength-selective filter M1, passes through the second wavelength-selective filter M2, and enters the image sensor 3. This allows the image sensor 3 to acquire an image of the area around the object S.

[0026] In this embodiment, the laser system 100 has a two-color radiation thermometer coaxial lens barrel 101. As shown in Fig. 1, the two-color radiation thermometer coaxial lens barrel 101 has a first sensor 10, a second sensor 20, an image sensor 3, a first wavelength-selective filter M1, a second wavelength-selective filter M2, and a third wavelength-selective filter M3. Specifically, the first sensor 10, the second sensor 20, the image sensor 3, the first wavelength-selective filter M1, the second wavelength-selective filter M2, and the third wavelength-selective filter M3 are built into a housing that constitutes the two-color radiation thermometer coaxial lens barrel 101.

[0027] 1, of the first sensor 10, the second sensor 20, and the temperature calculation unit 30 in the two-color radiation thermometer 1, the first sensor 10 and the second sensor 20 are built into the two-color radiation thermometer optical axis lens barrel 101, and the temperature calculation unit 30 is not built into the two-color radiation thermometer optical axis lens barrel 101, but this is not limiting. That is, the temperature calculation unit 30 may also be built into the two-color radiation thermometer optical axis lens barrel 101. When the temperature calculation unit 30 is not built into the two-color radiation thermometer optical axis lens barrel 101, the temperature calculation unit 30 may be a computer or the like separate from the two-color radiation thermometer optical axis lens barrel 101.

[0028] The laser system 100 further includes a temperature feedback correction unit 4. The temperature feedback correction unit 4 adjusts the output of the laser light La based on the temperature of the object S calculated by the two-color radiation thermometer 1. For example, the temperature feedback correction unit 4 adjusts the output of the laser light La by controlling the power input to the semiconductor laser element in the laser device 2 so that the temperature of the object S calculated by the two-color radiation thermometer 1 falls within a predetermined range. This allows the temperature of the object S to be kept within a certain range.

[0029] As an example, the laser system 100 in this embodiment is a laser soldering system or laser soldering device that solders components together using a laser beam. In this case, the target object S is a joining component before solder is applied and becomes solder after solder is applied. In other words, the two-color radiation thermometer 1 measures the temperatures of different materials. As shown in FIG. 1 , the laser system 100 also includes a feeder unit 5 having a nozzle and motor for supplying solder, and a solder feeder 6 that controls the feeder unit 5. The solder feed rate controlled by the solder feeder 6 via the feeder unit 5 may be controlled by a temperature feedback correction unit 4. When the laser system 100 is a laser soldering system or laser soldering device, the wavelength of the laser beam La is, for example, 980 nm, 940 nm, or 450 nm.

[0030] It should be noted that the laser system 100 is not limited to a laser soldering system or a laser soldering device. For example, the laser system 100 may be a laser processing system or a laser processing machine. In this case, the object S is a workpiece to be processed by the laser light La, and the two-color radiation thermometer 1 measures the temperature of the workpiece, which is the object S. An example of a laser processing system or a laser processing machine is a laser welding system or a laser welder. In this case, the object S is a workpiece to be welded by the laser light La, and the two-color radiation thermometer 1 measures the temperature of the object S to be welded.

[0031] Next, the features of the two-color radiation thermometer 1 in this embodiment will be described. When calculating temperature from two infrared rays with different wavelengths, the two-color radiation thermometer 1 in this embodiment uses a correction function calculated in advance based on the actually measured temperature. Below, a method for calculating this correction function and a method for calculating temperature using the correction function will be described in detail.

[0032] First, we will explain the relationship between the intensity ratio of two infrared rays detected by two sensors and temperature. In blackbody radiation, the approximate formula for the temperature curve calculated from the intensity ratio of two infrared rays detected by two sensors is expressed by the following approximate formula from Planck's radiation formula, where T (°C) is the temperature and Rate is the intensity ratio of the two infrared rays. In other words, the approximate formula for the temperature curve is proportional to the 0.38th power of the intensity ratio of the two infrared rays.

[0033]

number

[0034] In the above formula, the intensity of the first infrared ray, which has the shorter wavelength of the two infrared rays, is I S The intensity of the second infrared ray, which has the longer wavelength, is I L and the intensity ratio between the intensity of the first infrared ray and the intensity of the second infrared ray is Rate, the Rate is expressed by the following formula.

[0035]

number

[0036] In the temperature curve approximation formula, A is a coefficient. In other words, the relationship between the intensity ratio of two infrared rays and temperature differs depending on the material from which the infrared rays are emitted (= coefficient A differs). Therefore, it is a good idea to measure the temperature of each material to be measured, calculate coefficient A, and then correct the temperature.

[0037] Figure 2 shows the relationship between the temperature and the intensity ratio of two infrared rays emitted from a black body. Specifically, Figure 2 shows the relationship between the temperature and the intensity ratio of infrared rays with wavelengths around 2 μm and 3.5 μm.

[0038] In Figure 2, the solid line is a curve obtained by calculating the change in intensity at wavelengths of 2 μm and 3.5 μm at each temperature using the blackbody radiation formula. In Figure 2, the dashed line is a curve obtained by calculating the change in intensity at wavelengths of 2 μm and 3.5 μm at each temperature using the blackbody radiation formula. 0.38 The curve shown is for the case where A=188, assuming that T(℃)=A×(Rate). As shown above, by setting the coefficient A to 188, we can get closer to the formula for blackbody radiation. In other words, T(℃)=A×(Rate) 0.38 The approximate formula is valid. In this way, the temperature T can be expressed as an exponential function of the rate with a coefficient A.

[0039] Next, we will explain the relationship between the intensities of the two infrared rays with different wavelengths detected by the two sensors. The intensity of the first infrared ray, which has the shorter wavelength of the two infrared rays, is defined as I S The intensity of the second infrared ray, which has the longer wavelength, is I L Then, I S and I L is expressed by the following approximate formula: S I L In the following approximation, B is a coefficient. Thus, I S is I with coefficient B L can be expressed as an exponential function of

[0040]

number

[0041] As can be seen from the above approximation formula, the relationship between the intensities of the two infrared rays differs depending on the material from which the infrared rays are emitted. In other words, coefficient B differs depending on the material. Therefore, it is advisable to measure the temperature of each material to calculate coefficient B and correct the temperature.

[0042] Figure 3 shows the relationship between the intensities of the two infrared rays emitted from the materials used in Figure 2. Specifically, Figure 3 shows the relationship between the intensity of infrared rays with a wavelength of 2 μm (intensity on the short wavelength side) and the intensity of infrared rays with a wavelength of 3.5 μm (intensity on the long wavelength side).

[0043] In Figure 3, the solid line is the line obtained by calculating the intensity at wavelengths of 2 μm and 3.5 μm using the blackbody radiation formula. S =B×I L 1.75 Assuming that B=4×10 -4 This shows the line when the coefficient B is set to 4 × 10 -4 By doing so, we can get closer to the equation for blackbody radiation. S =B×I L 1.75 The approximate formula is valid. In this approximate formula, the multiplier (1.75) changes depending on the wavelength band of the infrared light used.

[0044] Based on the above findings, correction coefficients α and β used in the two-color radiation thermometer 1 of this embodiment were first calculated based on the measured temperature. The measured temperature was measured using a thermocouple. Furthermore, the intensities of the two infrared rays with different wavelengths were measured using the two-color radiation thermometer coaxial lens barrel 101 shown in FIG. 1, but they may also be measured using another device.

[0045] First, the correction coefficient α (first correction coefficient) will be explained. The correction coefficient α corresponds to the above coefficient A. Therefore, the correction coefficient α, the temperature T, and the intensity ratio of the two infrared rays Rate (=I S / IL ) is T(℃)=α×(Rate) 0.38 It is expressed by the approximate formula:

[0046] Then, for three materials (materials a, b, and c) whose Rate changes within a temperature range of 0°C to 600°C (more specifically, within a temperature range of 0°C to 300°C), the actual temperatures were measured, and the intensities of two infrared rays with different wavelengths emitted by the materials at that time were detected to calculate the Rate. In this embodiment, for each of the three materials, three different actual temperatures were measured, and the intensity ratio Rate at that time was calculated. Furthermore, of the two infrared rays detected, the wavelength of the short-wavelength infrared ray was set to 2 μm, and the wavelength of the long-wavelength infrared ray was set to 3.5 μm. In this embodiment, material a is black anodized aluminum, material b is solder, and material c is copper.

[0047] Specifically, for material a, T(℃)=α×(Rate) 0.38 Based on the approximation formula, the correction coefficient α was calculated from the measurement results. In this embodiment, as shown in the formula below, measurements were taken at three different actual temperatures, and α (α1, α2, α3) was calculated for each, and the average value was taken as α. As a result, α = 167.

[0048] α1=T1÷(Rate1) 0.38 α2=T2÷(Rate2) 0.38 α3=T3÷(Rate3) 0.38 α=(α1+α2+α3)÷3

[0049] The correction coefficient α was also calculated in the same manner for materials b and c. As a result, the correction coefficient α for material b was α=173, and the correction coefficient α for material c was α=153.

[0050] Figures 4A, 4B, and 4C show the results, plotting the measured temperature T (°C) and intensity ratio Rate for each material at three points, and also plotting the three points when the intensity ratio Rate is substituted into an approximate equation to which the correction coefficient for each material is applied. Figure 4A shows the results for material a (black anodized aluminum), Figure 4B shows the results for material b (solder), and Figure 4C shows the results for material c (copper). As shown in Figures 4A, 4B, and 4C, it can be seen that the calculated correction coefficient α is appropriate.

[0051] In this embodiment, the correction coefficient α is calculated using an approximate formula such as T(°C)=α×(Rate). 0.38 is used, but is not limited to this. That is, the correction coefficient α may be calculated using another approximation formula. Furthermore, in this embodiment, the correction coefficient α is calculated using the average value of three points, but is not limited to this. For example, the correction coefficient α may be calculated from only one point, or the correction coefficient α may be calculated as the average value of two or four or more points.

[0052] Next, the correction coefficient β (second correction coefficient) will be explained. The correction coefficient β corresponds to the above coefficient B. Therefore, the correction coefficient β and the intensities I S、 I L That is, I S = β × I L 1.75 It is expressed by the approximate formula:

[0053] Then, based on the intensities of the two infrared rays detected when calculating the correction coefficient α, a correction coefficient β was calculated for each of the materials a, b, and c.

[0054] Specifically, first, for material a, I S = β × I L 1.75 Based on the approximation formula, the correction coefficient β was calculated from the above measurement results. In this embodiment, measurements were taken at three different actual temperatures, so β ​​(β1, β2, β3) was calculated for each of the three points as shown in the formula below, and the average value was taken as β. As a result, β = 1.6.

[0055] β1=I S1 ÷(I L1 ) 1.75 β2=I S1 ÷(I L2 ) 1.75 β3=I S1 ÷(I L3 ) 1.75 β=(β1+β2+β3)÷3

[0056] The correction coefficient β was also calculated in the same manner for materials b and c. As a result, the correction coefficient β for material b was β=5.4, and the correction coefficient β for material c was α=18.7.

[0057] Figures 5A, 5B, and 5C show the results, and for each material, I S , I L The actual measured values ​​of were plotted at three points, and the correction coefficients for each material were applied to the approximate formula. L When I is substituted S The three points shown above are plotted. Note that Fig. 5A shows the results for material a (black anodized aluminum), Fig. 5B shows the results for material b (solder), and Fig. 5C shows the results for material c (copper). As shown in Figs. 5A, 5B, and 5C, it can be seen that the calculated correction coefficient β is appropriate.

[0058] In this embodiment, when calculating the correction coefficient β, I S = β × I L 1.75 However, this is not limiting. That is, the correction coefficient β may be calculated using another approximation formula. Furthermore, in this embodiment, the correction coefficient β is calculated using the average value of three points, but this is not limiting. For example, the correction coefficient β may be calculated from only one point, or the average value of two or four or more points may be used as the correction coefficient β.

[0059] Next, the calculated correction coefficients α and β are used to determine a correction function used when the temperature calculation unit 30 calculates the temperature.

[0060] Specifically, combinations of the correction coefficients α and β for each of material a, material b, and material c are plotted on a two-dimensional orthogonal coordinate system. In this embodiment, as shown in Figures 6 and 7, two sets of combinations of the correction coefficients α and β are calculated for material a, and two points corresponding to the two sets are plotted, one set of combinations of the correction coefficients α and β is calculated for material b, and one point corresponding to the one set is plotted, and two sets of combinations of the correction coefficients α and β are calculated for material c, and two points corresponding to the two sets are plotted.

[0061] Then, an approximate equation is calculated for multiple points of combinations of the correction coefficients α and β plotted on a two-dimensional orthogonal coordinate system. In other words, the plotted points for the correction coefficients α and β are fitted with the approximate equation, and correction values ​​for blank areas of the data are calculated. The approximate equation calculated in this way is the correction function.

[0062] In Figure 6, α is constant regardless of the value of β, and the average value of the three α values ​​is α AVE (α AVE =164). In other words, the correction function in FIG. 6 has a constant α.

[0063] On the other hand, in FIG. 7, a plurality of points of combinations of correction coefficients α and β are curve-approximated. In other words, the correction function is a quadratic function. In this case, the correction function is α=a×β 2 +b×β+c, where a, b, and c are constants.

[0064] In this way, the correction function is calculated using multiple correction coefficients α calculated in advance from the measured temperatures of each of multiple different materials (in this embodiment, materials a, b, and c) and multiple correction coefficients β calculated in advance from the measured temperatures of each of multiple different materials.

[0065] Next, a method for measuring the temperature of the target object S by the two-color radiation thermometer 1 using the correction function calculated in advance in this way will be described. That is, a method for calculating the temperature by the temperature calculation unit 30 in the two-color radiation thermometer 1 will be described.

[0066] The temperature calculation unit 30 first calculates a coefficient B (second coefficient) based on the first intensity of the first infrared ray IR1 detected by the first sensor 10 and the second intensity of the second infrared ray IR2 detected by the second sensor 20. Specifically, the coefficient B is calculated by S =B×I L 1.75 That is, the first intensity of the first infrared ray IR1 (short wavelength infrared ray) detected by the first sensor 10 can be calculated by the following relational expression. S and the second intensity of the second infrared ray IR2 (long wavelength infrared ray) detected by the second sensor 20 is I L Then, the coefficient B is B=I S ÷I L 1.75 It can be calculated as follows.

[0067] Next, the temperature calculation unit 30 calculates a coefficient A (first coefficient) by inputting the calculated coefficient B into the correction function. Specifically, the correction function is a function of correction coefficients α and β, and the correction coefficient α obtained by substituting coefficient B for the correction coefficient β of the correction function becomes coefficient A. For example, when the correction function of FIG. 6 (where α is constant) is used, α=A. Furthermore, when the quadratic correction function obtained in FIG. 7 is used, coefficient A is calculated by substituting coefficient B for the correction coefficient β of the quadratic function.

[0068] Next, the temperature calculation unit 30 calculates the temperature T of the object S based on the intensity ratio Rate, which is the ratio between the first intensity of the first infrared ray IR1 detected by the first sensor 10 and the second intensity of the second infrared ray IR2 detected by the second sensor 20, and the coefficient A (first coefficient) calculated by the correction function. Specifically, the temperature T is calculated as follows: T(°C)=A×(Rate) 0.38 It can be calculated using the following relational expression.

[0069] Here, the first intensity of the first infrared ray IR1, which is a short-wavelength infrared ray, is I S The second intensity of the second infrared ray IR2, which is a long wavelength infrared ray, is I L and the first intensity I of the first infrared ray IR1 S and the second intensity I of the second infrared IR2 LIf the intensity ratio is Rate, the intensity ratio Rate is Rate = I S / I L Therefore, the temperature T is expressed by the following equation: T=A×(I S / I L ) 0.38 That is, the temperature T can be calculated by the calculated coefficient A and the intensity I detected by the first sensor 10 and the second sensor 20. S , I L and T=A×(I S / I L ) 0.38 It can be calculated by substituting

[0070] In this way, the temperature calculation unit 30 can calculate the temperature T of the object S based on the first intensity of the first infrared ray IR1 detected by the first sensor 10 and the second intensity of the second infrared ray IR2 detected by the second sensor 20.

[0071] The results of comparing the temperatures calculated in this way (calculated temperatures) with the temperatures actually measured as described above (measured temperatures) are shown in Figures 8 and 9. Figure 8 shows the results when the correction function is the correction function in Figure 6 (with a constant α), and Figure 9 shows the results when the correction function is the quadratic function obtained in Figure 7.

[0072] 8 and 9, it can be seen that the temperature of an object can be measured with higher accuracy when the correction function is a quadratic function. In other words, fitting the correction coefficients α and β obtained by actual measurement with a quadratic function allows for more accurate approximate correction of the correlation between the correction coefficients α and β. In this way, it is preferable to use a quadratic function as the correction function used by the temperature calculation unit 30 when calculating the temperature.

[0073] As described above, the two-color radiation thermometer 1 according to this embodiment includes a first sensor 10 that detects a first intensity, which is the intensity of a first infrared ray IR1 emitted by the object S, a second sensor 20 that detects a second intensity, which is the intensity of a second infrared ray IR2 emitted by the object S and having a wavelength different from that of the first infrared ray IR1, and a temperature calculation unit 30 that calculates a coefficient A (first coefficient) by inputting a coefficient B (second coefficient) calculated from the first intensity detected by the first sensor 10 and the second intensity detected by the second sensor 20 into a correction function, and calculates the temperature of the object S based on the calculated coefficient A and an intensity ratio, which is the ratio of the first intensity detected by the first sensor 10 to the second intensity detected by the second sensor 20. In the two-color radiation thermometer 1 according to this embodiment, the correction function used by the temperature calculation unit 30 when calculating the temperature is calculated using correction coefficients α and β that are calculated in advance from the actually measured temperatures of each of a plurality of different materials.

[0074] As described above, the two-color radiation thermometer 1 according to this embodiment not only uses the intensity ratio of two infrared rays with different wavelengths, but also calculates a correction function in advance based on the measured temperature of the material, and calculates coefficients using this correction function to correct the temperature. In other words, the temperature is corrected taking into account information on infrared intensity (emissivity) that varies depending on the characteristics of the material. This allows the temperature of the object S to be measured with high accuracy.

[0075] Moreover, the two-color radiation thermometer 1 according to this embodiment can shorten the processing time for temperature calculation, and therefore the time for adjusting the output of the laser light by the temperature feedback correction unit 4 can also be shortened. For example, the processing time, which is the sum of the time for measuring the temperature by the two-color radiation thermometer 1 and the time from that measurement to converting it into a laser output value by the temperature feedback correction unit 4, is 10 ms or less.

[0076] The technology of the present disclosure can also be realized as a temperature measurement method. Specifically, the temperature measurement method according to the present embodiment is a measurement method for measuring the temperature of an object S emitting a first infrared ray IR1 and a second infrared ray IR2 having a wavelength different from that of the first infrared ray IR1, in which a coefficient B (second coefficient) calculated from a first intensity, which is the intensity of the first infrared ray IR1 detected by a first sensor 10, and a second intensity, which is the intensity of the second infrared ray IR2 detected by a second sensor 20, is input into a correction function to calculate a coefficient A (first coefficient), and the temperature of the object S is calculated based on the intensity ratio, which is the ratio between the first intensity detected by the first sensor 10 and the second intensity detected by the second sensor 20, and the calculated coefficient A. In the temperature measurement method according to the present embodiment, the correction function is calculated using correction coefficients α and β calculated in advance from the actually measured temperatures of each of a plurality of different materials.

[0077] In this way, in the temperature measurement method according to this embodiment, the temperature is corrected using a correction function calculated in advance based on the actual measured temperature of the material, so that the temperature of the object S can be measured with high accuracy.

[0078] (Variation) Although the technology of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments.

[0079] For example, in the above embodiment, when calculating the correction coefficients α and β, the wavelength of the short wavelength infrared ray is set to 2 μm and the wavelength of the long wavelength infrared ray is set to 3.5 μm, but this is not limited to this. For example, the correction coefficients α and β may be calculated by setting the wavelength of the short wavelength infrared ray to 2 μm and the wavelength of the long wavelength infrared ray to 11 μm. As shown in FIGS. 10 and 11, even in the combination of wavelengths 2 μm and 11 μm, the coefficient A is set to 198, and T(°C)=198×(Rate) 0.208 By using the approximate formula, the coefficient B can be set to 3×10 -30 As, I S =3×10 -30 ×I L 5By using this approximation, we can get closer to the equation for blackbody radiation. In other words, the temperature T can be expressed as an exponential function of the rate with a coefficient A, and I S is I with coefficient B L It can be expressed as an exponential function of the following. In Figures 10 and 11, a black body is used as the material.

[0080] In the above embodiment, material a is black anodized aluminum, material b is solder, and material c is copper, and the temperatures and infrared intensities are measured to calculate the correction coefficients α and β. Therefore, the temperature measurement range of the two-color radiation thermometer 1 is from 0° to 600°, but is not limited to this. For example, the temperature measurement range of the two-color radiation thermometer 1 may be from 0° to 2000°.

[0081] The temperature control method according to the above embodiment may be implemented as a computer program executed by a computer, or as a computer-readable recording medium storing the program. For example, the present disclosure may be implemented as a program that causes a computer to execute the temperature control method.

[0082] In addition, the present disclosure also includes forms obtained by applying various modifications to the above-described embodiments that a person skilled in the art would conceive, and forms realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure. Furthermore, the present disclosure also includes any combination of two or more claims from the multiple claims set forth in the claims at the time of filing, provided that there is no technical contradiction. For example, when a dependent claim set forth in the claims at the time of filing is made into a multiple claim or multiple multiple claims that cite all of the superordinate claims within the scope of the technical contradiction, the present disclosure also includes all combinations of claims included in that multiple claim or multiple multiple multiple claim. [Industrial Applicability]

[0083] The technology of the present disclosure is useful as a thermometer or a temperature measurement method for measuring the temperature of an object. [Explanation of symbols]

[0084] 1 Two-color radiation thermometer 2. Laser device 3. Image sensor 4 Temperature Feedback Compensation Unit 5 Feeder section 6 Solder feeder 10 First sensor 20 Second sensor 30 Temperature calculation section 100 Laser System 101 Two-color radiation thermometer coaxial lens barrel M1 First wavelength selection filter M2 Second wavelength selective filter M3 Third wavelength selective filter IR1 First infrared IR2 Second Infrared La laser light Lb visible light S Object

Claims

1. a first sensor that detects a first intensity, which is the intensity of a first infrared ray emitted by an object; a second sensor that detects a second intensity, which is the intensity of a second infrared ray emitted by the object and having a wavelength different from the wavelength of the first infrared ray; a temperature calculation unit that calculates a first coefficient by inputting a second coefficient calculated from the first intensity detected by the first sensor and the second intensity detected by the second sensor into a correction function, and calculates a temperature of the object based on an intensity ratio that is a ratio between the first intensity detected by the first sensor and the second intensity detected by the second sensor and the calculated first coefficient, the correction function is calculated using a first correction coefficient calculated in advance from the actual measured temperature of each of a plurality of different materials and a second correction coefficient calculated in advance from the actual measured temperature of each of the plurality of different materials; Two-color radiation thermometer.

2. the correction function is an approximation formula calculated by plotting a combination of the first correction coefficient and the second correction coefficient on a two-dimensional orthogonal coordinate system at a plurality of points. The two-color radiation thermometer according to claim 1 .

3. When the first correction coefficient is α and the second correction coefficient is β, The correction function is α=a×β ２ +b × β + c, 3. The two-color radiation thermometer according to claim 2.

4. the first correction coefficient is calculated in advance using a relational expression expressed by an intensity of the first infrared ray and an intensity of the second infrared ray radiated from the material when the actual temperature is measured, the second correction coefficient is calculated in advance by a relational expression expressed by an intensity ratio, which is a ratio between an intensity of the first infrared ray radiated by the material and an intensity of the second infrared ray radiated by the material when measuring the actual temperature, and the actual temperature; 4. The two-color radiation thermometer according to claim 2 or 3.

5. The wavelength of the first infrared ray is shorter than the wavelength of the second infrared ray, The intensity of the first infrared ray is I Ｓ and the intensity of the second infrared ray is I Ｌ and the intensity ratio between the intensity of the first infrared ray and the intensity of the second infrared ray is Rate, Rate = I Ｓ / I Ｌ That is, The two-color radiation thermometer according to any one of claims 1 to 3.

6. The temperature measurement range of the two-color radiation thermometer is 0° or more and 600° or less. The two-color radiation thermometer according to any one of claims 1 to 3.

7. a laser device that outputs laser light to be irradiated onto an object; The two-color radiation thermometer according to any one of claims 1 to 3, The two-color radiation thermometer measures the temperature of the object. Laser system.

8. and adjusting the output of the laser light based on the temperature of the object calculated by the two-color radiation thermometer.

8. The laser system of claim 7.

9. A measurement method for measuring the temperature of an object that emits a first infrared ray and a second infrared ray having a wavelength different from that of the first infrared ray, comprising: calculating a first coefficient by inputting a second coefficient calculated from a first intensity, which is the intensity of the first infrared ray detected by a first sensor, and a second intensity, which is the second intensity of the second infrared ray detected by a second sensor, into a correction function; and calculating a temperature of the object based on an intensity ratio, which is the ratio of the first intensity detected by the first sensor to the second intensity detected by the second sensor, and the calculated first coefficient; the correction function is calculated using a first correction coefficient calculated in advance from the actual measured temperature of each of a plurality of different materials and a second correction coefficient calculated in advance from the actual measured temperature of each of the plurality of different materials; Temperature measurement method.

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