JPS6055768B2 - Infrared temperature measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an infrared temperature measuring device, and more particularly to an improvement in a temperature calibration method for an infrared temperature measuring device.

Infrared imaging devices convert and display the infrared radiation naturally emitted by objects into visible images, but there is generally a certain law between the temperature of an object and the infrared energy radiated from the object. By utilizing this fact, the infrared imaging device can function as a non-contact temperature measuring device.

The present invention relates to a device for measuring temperature in this manner. This type of temperature measurement device is equipped with a temperature display section that serves as an interface with the measuring person, and the temperature display section shows the brightness or temperature scale of a reference heat source whose temperature is known, and the temperature of the object to be measured. The temperature of the object is measured by displaying and comparing the brightness or temperature scale. In this case, it is assumed that the temperature of the object to be measured is already known. As will be described later, this infrared imaging device for temperature measurement includes an optical scanning system that optically scans the object to be measured, and a photoelectric conversion that converts the optical imaging and the scanned infrared rays from the scanning system into electrical signals. system, an amplification system that amplifies the electrical signal from the photoelectric conversion system,
It consists of a DC component regeneration system that adds a DC component to an electrical signal, and a temperature display means that displays the temperature based on the electrical signal obtained through these systems. Here, the DC component is applied to the DC component regeneration system as a reference voltage obtained by photoelectrically converting radiation from a reference heat source built into the infrared imaging device, and this reference heat source serves as a temperature reference. . Therefore, even if the temperature reference itself can be accurately obtained, there is no guarantee that the temperature of the object can be accurately obtained without error over a wide temperature range. This is because the temperature range is determined by the total gain of the various systems mentioned above, and unless there is perfect linearity in this total gain, it will not be possible to accurately measure the temperature of the target without error over a wide temperature range. It is impossible to display it in However, it is technically difficult to realize a system with perfect linearity in the overall gain, and there is a drawback that temperature measurement with sufficiently small errors cannot be performed over a wide temperature range. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an infrared temperature measuring device which eliminates the above-mentioned drawbacks and is capable of accurately measuring temperature.

In accordance with the above object, the present invention provides two reference heat sources with temperatures T1 and T2 in the device, obtains a difference Δ■ between two reference voltages V1 and V2 from these two reference heat sources, and
The present invention is characterized in that the total gain is adjusted so that the ratio of =1T1-T2l and Δ■ is always constant.

The present invention will be explained below with reference to the drawings. FIG. 1 is a block diagram of a conventional infrared imaging device for temperature measurement.

In this figure, reference numeral 11 denotes an optical scanning mechanism, which receives the infrared rays P irradiated from the temperature measurement object 0 and scans it with a scan mirror (not shown). The light is focused and irradiated onto the photoelectric converter 13. This photoelectric converter 13 is made of, for example, mercury-cadmium tellurium, receives the focused infrared rays P, and outputs an electric signal EOut proportional to its power. This electric signal EOut is AC amplified in an AC amplifier 14. This AC amplification. Since the electric signal thus generated has lost its DC component and there is no standard for temperature measurement, the DC component is added by the DC component regenerator 15. This results in
Temperature display 16 displays a brightness or temperature scale. Here, the DC component to be applied to the DC component regenerator 15 is;
This is an important part as it serves as the standard for temperature measurement. This is set in the next block in FIG. In this figure, 17
is a reference heat source having a temperature T1 for setting a reference temperature, and is placed 1 near the scan mirror (inside block 11) in the infrared imaging device. This scanning mirror is a rotating or vibrating reflecting mirror, and alternately scans the temperature object 0 and the reference heat source 17. On the other hand, reference heat source 17
By obtaining a reference temperature voltage r via the temperature sensor 18 and the reference temperature voltage generator 19 and applying it to the DC component regenerator 15 as a DC component, the electricity from the reference heat source 17 obtained by the above-mentioned scan is DC component regeneration is performed on the signal EOut. That is, in the apparatus shown in FIG. 1, the reference heat source serves as the reference for temperature measurement. However, in this device, there is a possibility that the total gain determined by the optical scanning mechanism 11, the condensing system 12, the photoelectric converter 13, the AC amplifier 14, etc. will change, and the target object 0) may change in the voltage range outside the reference voltage Er. There is a possibility that a deviation will occur in the relationship between the actual infrared power from the temperature indicator 16 and the electrical signal output to the temperature display 16. Therefore, it is difficult to guarantee the accuracy of temperature measurement over a wide temperature range. Therefore, the present invention solves the above-mentioned problems based on the principle described below.

That is, conventionally, as shown in FIG. 2A, the reference heat source 17
Assuming that the output voltage to the temperature display 16 obtained through the temperature sensor 18 (temperature T1 = 30°C) and the reference temperature voltage generator 19 is T1 on the temperature scale T-S, this first Blocks 11, 12, 13 in the figure,
If the output voltage to the temperature indicator 16 obtained through 14 is T1'' on the scale T-S, then this T/
By matching T1 with T1, the temperature measurement standard is set. However, as described above, in this case, it is not possible to obtain an accurate output voltage for any temperature over a wide temperature range other than 30°C. Therefore, the present invention adds another reference heat source (temperature T2 = 60°C) to obtain the output voltage T2 of the temperature sensor system and the output voltage T2'' of the optical/amplifier system as shown in Fig. 2B. , the differential voltage ΔV between T1 and T2 and the differential voltage ΔV'' between T1'' and T2'' are made to match, respectively. Furthermore, T1 and T1'' (or T2
If the temperature is adjusted so that T2'' and Another reference heat source 21 is further added to the block, which is output to the temperature display 16 as a second reference voltage T2 via a temperature sensor 22 and a reference temperature voltage generator 23. The reference temperature voltage T1 is also output to the temperature display 16. Then, the voltage difference ΔV″ mentioned above is expressed as Δ
The operation to match V can be performed by adjusting the optical system aperture in the optical scanning mechanism 11 using the adjustment mechanism 24, adjusting the bias current of the photoelectric converter 13, adjusting the gain of the AC amplifier 14, or a combination thereof. It's easy to do. In addition, in FIG. 2B, the operation to match T1'' with T1 can be easily performed by adjusting the variable voltage source 25. Note that the temperature of the object is approximately T. If it is known that the temperature of the object is inside or outside, T2 It is desirable to select T2 so that TO>T1 as 〉T1.As explained above,
According to the present invention, an infrared imaging device for temperature measurement that can accurately measure temperature over a wide temperature range is realized.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional infrared temperature measuring device, Figure 2A
FIG. 3 is a diagram for explaining the principle of the present invention, and FIG. 3 is a block diagram showing an embodiment based on the present invention. In the figure, 11 is an optical scanning mechanism, 12 is a condenser, and 13
14 is a photoelectric converter, 14 is an AC amplifier, 15 is a DC regenerator, 16 is a temperature display, 17 and 21 are reference heat sources, 19
and 23 is a reference temperature temperature generator, 24 is an adjustment mechanism, 2
5 is a variable power supply.

Claims (1)

[Claims] 1. An optical scanning system that optically scans the object to be temperature measured and a reference heat source, a photoelectric converter that receives infrared rays from the optical scanning system and obtains an electrical signal corresponding to the infrared power, and amplifies the electrical signal. an electrical system equipped with an amplifier that performs the control, a DC regenerator that adds a predetermined DC component corresponding to the known temperature of the reference heat source to the electrical signal from the electrical system, and an electrical signal that has passed through the DC regenerator. In the infrared temperature measuring device, the infrared temperature measuring device has a temperature display section that performs A first temperature sensor system and a second temperature sensor system are provided that generate reference voltages respectively corresponding to the respective temperatures of the reference heat source, and the temperature display section is provided with the two temperature sensor systems that generate the reference voltages respectively corresponding to the respective temperatures of the reference heat source. A temperature scale is provided for comparing and displaying a temperature difference between the respective temperatures of the reference heat source and a temperature difference between the respective temperatures of the two reference heat sources obtained through the first and second temperature sensor systems; An infrared temperature measuring device characterized in that the optical scanning system or an adjustable adjustment mechanism is added so that the values are equalized.