JPS6058408B2 - radiation thermometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation thermometer that measures the temperature of an object by using radiant energy from the object.

Conventionally, radiation thermometers include monochromatic thermometers that determine the object temperature from the amount of radiant energy from the object to be measured, and two-color thermometers that determine the object temperature from the ratio of spectral radiant energy of two different wavelengths.

However, the electrical signals obtained in both cases have a non-linear relationship with temperature, and if you want to linearize them, you will need an A-D converter that performs analog signal processing, making the circuit that much more complicated. However, there was a problem in that it was expensive. In view of the above points, it is an object of the present invention to provide a radiation thermometer which uses a simple circuit, does not require a linearizer, and can also obtain a digital output.

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention.

In the figure, 1 is the object to be measured, 2 is a condenser lens that collects the radiant energy from the object to be measured, 3 is a detector that receives the radiant energy collected by the condenser lens 2 and converts it into an electrical signal, 4 5 is a signal separator that separates and extracts a first output signal and a second output signal Eo corresponding to two wavelengths of the radiation energy from the object to be measured 1 from the output of the detector 3; 5 is a signal separator 4; An amplifier that amplifies the first output signal with a predetermined amplification degree α; 6 a comparator that compares the output signal Ec of the amplifier 5 and the potential of a capacitor C of a time constant circuit 7 consisting of a parallel connection of a capacitor C) and a resistor R; , 8 is a pulse generator such as a monostable multivibrator that outputs the output pulse signal of the comparator 6, 9 is an integrator that integrates the pulse signal of the pulse generator 8 to obtain an analog signal voltage, and 101 is the output pulse signal from the integrator 9. A first output terminal 102 from which an analog output signal is taken out is taken out from a second output terminal 102 of the digitizer of the pulse generator 8 . Note that as the temperature of the object to be measured 1 rises, the difference between the signal Ec obtained by multiplying the first output signal corresponding to the two wavelengths by α and the second output signal EO becomes smaller.
The oscillation period becomes short, and as the temperature decreases, the oscillation period becomes longer. The temperature of the object to be measured is determined from the output signal of the comparator 6 or the pulse generator 7, and the principle is as follows. The discharge characteristic of the time constant circuit 7 is expressed by the following equation, assuming that the voltage e=EO at time t=o. If e=Ec and t=Tc, then the following is obtained.

This is what you get.

On the other hand, according to Wien's equation, the radiant energy E(λI,T) at wavelength λI and temperature T is expressed as follows.

The emissivity of the object to be measured for two wavelengths λ1 and λ2 is ε1,
E2, the radiant energies El and E2 at this time are as shown in the following equation.

Since the radiation energy corresponding to these wavelengths λ1 and λ2 is incident on the detector 3, the following equation holds true. Using equation (3), “Once So1 gradient = −So Ne5−±...
・If α is chosen so that (9) is obtained, then equation (9) becomes (
Equation 10 becomes.

In other words, the temperature T and the frequency Fc are proportional, and the temperature of the object to be measured can be directly measured by measuring the frequency FC. As described above, the present invention compares the radiant energy of two wavelengths from the object to be measured, charges and discharges the time constant circuit, extracts the oscillation pulse signal from this, and measures the temperature of the object to be measured. This is a radiation thermometer designed to Therefore, since the oscillation pulse signal is directly proportional to the temperature, by using this pulse signal for measurement, there is no need for a special linearizer, and the circuit can be significantly simplified, resulting in high precision and high reliability. Become something.

Also, since the measurement signal can be obtained directly as a digital signal,
No A-D converter is required, making digital display and external output easy.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, and FIG.
The figure is a waveform explanatory diagram. 1...Object to be measured, 3...Detector, 4
... Signal separator, 5 ... Amplifier, 6.
...Comparator, 7...Time constant circuit, C...
...Capacitor.

Claims (1)

[Claims] 1. A detector that receives radiant energy from the object to be measured, and a signal separator that separates the output of this detector into first and second signals corresponding to two wavelengths of the radiant energy from the object to be measured. and an amplifier that amplifies the first signal of this signal separator, and the output of this amplifier is compared with the output of the time constant circuit, and when the discharge output of the time constant circuit becomes smaller than the amplifier output, the output signal is a comparator that generates a second output signal of the signal separator; and switch means that charges a second output signal of the signal separator to a capacitor of the time constant circuit when the output signal of the comparator is generated; A radiation thermometer characterized in that the temperature of the object to be measured is measured from a signal.