JPS6130728A - Measurement of infrared radiation temperature - Google Patents

Abstract

PURPOSE:To measure temp. over a wide range without lowering temp. resolving powder, by enhancing the frequency of a chopper when the output of a detector exceeds a preset range to receive the same in the dynamic range of an amplifier. CONSTITUTION:A data processor 17, which has an operation circuit 18 and a correction amount generation circuit 19 and operates the outputs of A/D 16 and a rotary number detector 10 to calsulate the temp. of an article to be measured, is provided. A reference black body 5 is used and the temp. of the article to be measured is calculated by the circuit 18 and several kinds of correction signals are generated stepwise by the circuit 19 so as to change the number of rotations of a motor 3 so as to follow the change in measuring temp. when measuring temp. is changed by the measuring temp. information from the circuit 18 and the temp. information of the reference black body from an amplifier 8. Further, the values of these correction signals are utilized as the input information at the time of the operation by the circuit 18 to calculate a measured value. By this method, the range of measuring temp. can be enlarged without changing the amplification degree of the amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an infrared radiation temperature measuring method for non-contactly measuring the temperature of an object with low heat capacity, a distant object, a moving object, etc.

Configuration of the conventional example and its problems Figure 1 is a diagram showing the conventional method for measuring infrared radiation temperature. 3 is a motor, 4 is a chopper having a plurality of slots rotated by the motor 3, 6 is a reference black body that provides a reference value for the measured temperature, 6 is an infrared detector, and 6 is an infrared detector. A pyro element or the like that utilizes the electric effect is used. 7.8 is an amplifier, 9 is a temperature measuring element such as a thermistor, 10 is a chopper rotation speed detector such as a photointerrupter, 11 is a data processor, 12 is a display for temperature, etc., and 13 is a precision sensor for measuring the rotational speed of the motor. This is a motor control circuit that controls the

To detect the temperature with the above configuration, the infrared energy 1 of the object to be measured is focused on the detector 6 by the optical system 2, while the infrared energy from the reference black body 6 is converted into alternating current by the chopper 4. It is detected by the detectors above. Since the chopper 4 has a slit in a part of the blade, the amount of infrared rays passing through the slit is proportional to the temperature TM of the object to be measured. Blackbody temperature T. It will be proportional to. However, when a pyro-type detection element is used as the detector 6, the output is the temperature T. depends on the difference TB.

Generally, it is known that when a pyro-type detection element is used as a detector, the output IVI is given as shown in equation (1) below.

where k is a constant (-1), C is the capacitance of the detector, ω' is the specific heat of the detector, ρ is the density of the detector, h is the thickness of the detector, ω
Hachi”! 7P frequency (2πf), εfd radiation L σ is Stefan Boltzmann constant? (-5,673X10 W
-a*deg'), TB is the temperature difference between the measured object and the reference black body, and Ab is the pyro constant (=T 6, OX 10 coul/z 0K).

Therefore, the temperature (TM) of the object to be measured can be determined from the output V assuming that the temperature (To) of the reference black body 6 is known. In this case, the output of the detector 6 is input to the data processor 11 via the amplifier 7. Since the output of the amplifier 7 is converted into alternating current by the chopper 4, the alternating current output is synchronously rectified by the output of the rotation speed detector 10, and the temperature information of the reference black body 6 from the temperature measuring element 9 is sent to the amplifier 8. is similarly input to the data processor 11 via , and as described above (1
) The temperature of the object to be measured TM (i7 calculation) can be determined and displayed on the display 12. However,
Since it changes in proportion to the difference between the temperature TM and To of the object to be measured, for example, the voltage of the detector when the temperature is 300'C is 2000'C.
When it comes to C, it becomes about 10 times as large, so it has the disadvantage that it cannot be placed within the dynamic range of the amplifier, resulting in a narrow measurement range.

Purpose of the Invention The present invention eliminates the drawbacks of the conventional examples described above, and aims to provide a method for measuring infrared radiation temperature that can be measured without reducing temperature resolution even if the measurement range increases. It is something to do.

Structure of the Invention In order to achieve the above object, the present invention utilizes the fact that the sensitivity of the detector depends on the frequency of the chopper.
When the output from the detector exceeds a predetermined range, the frequency of the chipper is raised to stay within the dynamic range of the amplifier, making it possible to measure temperatures over a wide range. □ Description of Examples The measurement method of the present invention will be described below with reference to the drawings. In FIG. 2, 16 indicates the measured value from amplifier 7 and amplifier 8.
16 is an analog-to-digital converter (MU/D), 1-r is an input of the output of A/D 16 and a rotation speed detector 10 such as a photointerrupter. This is a data processing machine that performs calculations to determine the temperature TM of the object to be measured, and has an internal calculation circuit 18. A correction amount generation circuit 19 is provided, and a microcomputer may be used for processing if necessary. The same reference numerals as in other FIG. 1 represent the same names.

Next, the operation will be explained. The arithmetic circuit 18 calculates the temperature T of the object to be measured,
However, in the method of this embodiment, the frequency ω of the chopper was kept constant even if the measured temperature changed in the conventional example (1), but in the method of the present example, the calculation circuit 18 Based on the measured temperature information and reference blackbody temperature information obtained from the output of
9, several types of correction signals (ω') are generated in stages.

In this case, even if the measured temperature changes, the output of the arithmetic circuit 18 will be kept constant, but the value of the correction signal (ω') is used as input information for the arithmetic operation of the arithmetic circuit 18, and the measured value What is necessary is to find it and display it on the display 12.

In addition, in the above configuration, the configuration of the data processor 17 itself can be easily performed using a known technique.

Further, the A/D 16 is for converting analog data into digital data so that it can be handled by the data processor 17.

Effects of the Invention As is clear from the above explanation, according to the present invention, the voltage obtained from the amplifier is different from that at 3°C and 2000°C.
In the case of 'C, it becomes about 10 times, and therefore, by increasing the chopper frequency about 10 times, the measurement temperature range can be expanded without changing the amplification degree of the amplifier. Furthermore, by measuring the frequency of the chopper using, for example, a fumetointerlager, there is an advantage that no measurement error occurs because the calculation is performed even if there is some error.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining a conventional method for measuring infrared radiation temperature, and FIG. 2 is a block diagram for explaining an embodiment of the method for measuring infrared radiation temperature according to the present invention. 4...Chopper, 5...Reference black body, 6...
...Detector, 18...Arithmetic circuit, 19...
...Correction amount generation circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] Infrared energy from the object to be measured and infrared energy from the reference blackbody are alternately introduced into the detector via a chopper rotated by a motor, and the output of the detector and the temperature measurement value of the reference blackbody are used to calculate the temperature of the object to be measured. A method for measuring infrared radiation temperature, characterized in that when calculating the temperature of an object by calculation, the rotation speed of the motor is changed to correct the calculation result so that it becomes a constant value with respect to temperature changes of the object to be measured. .