JPH0236171B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an infrared temperature measuring device used for temperature measurement in physical analysis, precision measurement, heat treatment, etc. In the semiconductor industry, temperature increases due to joule heating of electrical circuit elements are an important problem, and infrared thermometers have been used because a non-contact type is required for temperature measurement. Also, recently, the development of high-speed response elements and optoelectronics has been remarkable.
In this case, fast electronic phenomena are accompanied by fast thermal transients. Furthermore, in precision industries that use ion beams,
The beam generates heat, but when the beam fluctuates or during pulse operation (e.g. in a fusion reactor), rapid temperature changes are caused in the area irradiated by the beam, resulting in rapid temperature response. Speed is required. Traditionally, so-called monochromatic infrared thermometers have been used for this purpose, but these thermometers cannot measure the absolute value of temperature because they are greatly affected by the infrared emissivity of the object being measured. was extremely difficult. Furthermore, conventionally, a two-wavelength comparison type thermometer has been used as a thermometer that is not easily affected by emissivity, but this requires the use of a mechanical chopper when comparing the intensities of the two wavelengths. The response time is limited to 10 milliseconds, making high-speed response impossible. Therefore, in order to measure temperature without being affected by emissivity and with a fast response, it is necessary to use a single-wavelength infrared thermometer and a dual-wavelength infrared thermometer together. When performing measurements, not only is the equipment expensive, but it is difficult to calibrate the temperature of the entire system, reducing reliability. Furthermore, it is extremely difficult to match the shape and position of the light spot on the surface to be measured by two different types of measuring instruments. The present invention solves the above problems and has high-speed response of less than milliseconds by appropriately combining two optical systems and their signal processing systems, and also automatically performs emissivity correction. The object of the present invention is to provide a non-contact infrared temperature measuring device that can obtain the desired temperature. The infrared temperature measuring device of the present invention includes a single wavelength optical system,
a first electric circuit system that processes the output of this optical system;
a two-wavelength comparison optical system; a second electric circuit system for processing the output of the optical system; and a second electric circuit system capable of receiving the output of the two-wavelength comparison optical system and performing emissivity correction on the output of the single-wavelength optical system at high speed. It is characterized by comprising an emissivity correction circuit. The invention will be explained with reference to the drawings. The infrared temperature measuring device of the present invention includes a measurement main body housing two optical systems, and an electric circuit system for both optical systems. That is, as shown in FIG. 1, the main body 1 of the infrared temperature measuring device of the present invention includes a high-speed infrared sensor 2, a single-wavelength optical system A for high-speed response in a Cassegrain arrangement having a perforated concave reflector 3, a convex lens, and a filter (window). ) 5 and a two-wavelength comparison optical system B having an infrared sensor 7 for two-wavelength comparison measurement. The infrared sensor 2 is housed in a liquid nitrogen container 8 so that its operating temperature is 77 K, and its measurement wavelength is 1.8 to 5.5 μm. This infrared sensor 2 is made of, for example, indium/antimony, but it can also be made of materials such as indium/arsenic, cadmium, mercury, tellurium, or the like. The optical system B of the infrared sensor 7 chops the incident infrared light using an optical filter 5 that selects two wavelengths, for example, 2.02 μm and 2.33 μm, so that infrared light of two different wavelengths can reach the infrared sensor 7. Do it like this. The infrared sensor 7 is of a two-wavelength comparison type and is made of lead sulfide so that it can be used at room temperature. or,
It is assumed that this sensor 7 has a sufficiently faster response than the chopping time of the optical filter. Both of these optical systems A and B are housed in an outer case 9 and are arranged so that their optical axes and the light spots 11 on the surface of the object to be measured 10 coincide with each other.
A viewing window 12 is provided for sighting, which makes it possible to position and adjust the light spot 11 on the surface of the object 10 to be measured. Therefore, infrared light information from the same point can be input to both optical systems A and B and their electrical circuits. In addition, two conductive wires 13 and 1 lead out from the output side of the outer box 9.
4 to electrical circuit systems A' and B' (second
(see figure) respectively. That is, as shown in FIG. 2, the electric circuit system A' includes a buffer amplifier 15 connected to the output conductor 13 of the main body 1, a single wavelength main amplifier 16, a linearizer 17, and an A/D converter 18. , and a digital display 19. The electric circuit system B' includes a preamplifier 20, a logarithmic amplifier 21 for comparing two wavelengths, an emissivity correction circuit 22, and an emissivity display 23.
This emissivity correction circuit 22 includes the logarithmic amplifier 21
The emissivity calculation circuit 24 includes an emissivity calculation circuit 24 built in, an emissivity correction calculation circuit 26 connected to the output side of the emissivity calculation circuit 24 via an automatic switch 25, and an emissivity setting circuit 27. Further, a room temperature compensation circuit 28 is provided between the main amplifier 16 of the electric circuit system A' and the two-wavelength comparison logarithmic amplifier 21 of the electric circuit system B', so that the temperature of the entire apparatus can be calibrated. The operation of the infrared temperature measuring device of the present invention constructed in this manner is as follows. Now, while looking at the sight glass 12, the measurement spot 11 on the surface of the object to be measured 10 is positioned. In this way, the radiation at the infrared temperature of the measurement spot 11 is reflected by the perforated concave reflector 3 in the fast-response single-wavelength optical system A, and reaches the infrared sensor 2, where it is continuously converted into electricity. The signal is converted into a signal and reaches the infrared sensor 7 through the central hole of the concave reflector 3, the convex lens 4, and the filter 5 of the optical chopper 6 in the two-wavelength comparison optical system B. In this case, the incident infrared light is chopped into light of two wavelengths by the filter 5, so that infrared light of two different wavelengths is incident on the sensor 7. The infrared light of the two different wavelengths of the optical system B is detected by the infrared sensor 7, converted into an electrical signal, and supplied to the preamplifier 20 of the electrical circuit system B', where it is amplified and converted into two wavelengths. Comparison logarithmic amplifier 2
1, where it is voltage amplified and sampled and held, and then subjected to logarithmic conversion and subtraction processing in the emissivity calculation circuit 24 to calculate the emissivity. The output of the emissivity calculation circuit 24, that is, the electrical signal corresponding to the emissivity is as follows:
It is displayed on the emissivity display 23 and the switch 2
5 to the emissivity correction calculation circuit 26 of the emissivity correction circuit 22 to calculate an emissivity correction coefficient,
The output is supplied to the emissivity setting circuit 27, which allows the emissivity correction value to be finally and continuously set. The switch 25 is normally an automatic switch, but it can also be changed to a manual switch. Furthermore, the emissivity setting circuit 27 can also be switched to manual setting. Furthermore, the emissivity correction calculation circuit 26
Since it is constructed using a microcomputer with a built-in A/D converter, it introduces almost no noise and can be used stably for a long time with high precision. Further, the infrared light of the optical system A is continuously detected by the infrared sensor 2 and converted into an electric signal.
The signal is supplied to the buffer amplifier 15 of the electric circuit system A', where it is amplified and supplied to the single wavelength main amplifier 16, where it is temperature compensated by the room temperature compensation circuit 28 and the emissivity is adjusted by the emissivity setting circuit 27. Make corrections. The temperature signal, which is the analog output of the main amplifier 16 which has been temperature compensated and emissivity corrected in this way, is sent to the high speed linearizer 17 and the A/D converter 1.
8, the temperature is displayed on a digital display 19, and the temperature signal is supplied from a temperature signal output terminal 29 to a circuit to be used, for example, a normal temperature control circuit. Next, various characteristics of the infrared temperature measuring device of the present invention and a conventional infrared thermometer are shown below.

[Table] As is clear from the above table, since the infrared temperature measuring device of the present invention is configured as described above, even if the infrared emissivity of the surface of the object to be measured changes over time, Emissivity can be corrected and temperature can be measured accurately with high-speed response. For example, even if the surface of the object to be measured is undergoing surface oxidation or changes in surface condition, the temperature of the object can be accurately measured. Furthermore, even if the emissivity of the object to be measured differs depending on the location, the temperature can be measured accurately and with a high-speed response within the resolution of a spot size. For example, it becomes possible to perform high-speed response measurements of mixtures or composites of substances with different emissivities. Further, the infrared temperature measuring device of the present invention is highly reliable and inexpensive because it functions as both a fast response thermometer and an emissivity measuring device, and the temperature is calibrated as a whole. The present invention is not limited to the above-mentioned examples, and various modifications can be made. For example, in the example described above, two infrared sensors were used, but one
It is also possible to use two infrared sensors for both optical systems. In this case, the temperature measurement is performed in temporally divided manner, and therefore the emissivity correction is also made intermittently.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an optical system of an infrared temperature measuring device of the present invention, and FIG. 2 is a block diagram showing an electric circuit for processing the output from the optical system. 1... Device body, 2, 7... Infrared sensor, 3
... Concave reflective mirror with holes, 4 ... Convex lens, 5 ... Filter (6), 6 ... Optical chopper, 8 ... Liquid nitrogen container, 9 ... Device outer box, 10 ... Object to be measured, 11
...Measuring spot, 12...Peephole for aiming, 1
3, 14... Output conductor, 15... Buffer amplifier, 16... Single wavelength main amplifier, 17... Linearizer, 18... A/D converter, 19... Digital display, 20... Front amplifier, 21... dual wavelength comparison logarithmic amplifier, 22... emissivity correction circuit,
23...Emissivity display, 24...Emissivity calculation circuit, 25...Switch, 26...Emissivity correction calculation circuit, 27...Emissivity setting circuit, 28...Room temperature compensation circuit, 29...Temperature signal Output terminal.

Claims (1)

[Scope of Claims] 1. A single wavelength optical system, an electric circuit system that processes the output signal of the optical system, a two-wavelength comparison optical system, an electric circuit system that processes the output signal of the optical system, and An infrared temperature measuring device comprising: an emissivity correction circuit that receives the output of the wavelength optical system and can perform emissivity correction on the output of the single wavelength optical system at high speed. 2. The infrared temperature measuring device according to claim 1, wherein the single wavelength optical system includes a concave reflecting mirror with a hole arranged in a Cassegrain arrangement and a high-speed response infrared sensor. 3. The infrared temperature measuring device according to claim 1, wherein the two-wavelength comparison optical system includes a convex lens, an optical chopper with a filter, and an infrared sensor. 4. The electric circuit system of the single wavelength optical system includes a buffer amplifier that receives the output of the infrared sensor, a single wavelength main amplifier, a linearizer that makes the output of the main amplifier linear with respect to temperature changes, and an analog output of the linearizer. Claim 1, characterized in that it comprises an A/D converter for converting into a digital value, and a digital display for displaying the output of the converter.
The infrared temperature measuring device described in Section 1. 5. The electric circuit system of the two-wavelength comparison optical system includes the amplifier that receives the output of the infrared sensor, the two-wavelength comparison logarithmic amplifier that receives the output of the amplifier, the emissivity calculation circuit incorporated in the logarithmic amplifier, and the emissivity Claim 1 characterized in that it comprises a display device.
The infrared temperature measuring device described in Section 1. 6. The emissivity correction circuit includes an emissivity correction calculation circuit that receives the output of the emissivity calculation circuit, and an emissivity setting circuit that receives the output of the calculation circuit. The infrared temperature measuring device according to item 5. 7. The infrared temperature measuring device according to claim 1, wherein the single wavelength optical system and the dual wavelength comparison optical system are housed in a single container.