JPS62116226A - Infrared thermometer - Google Patents

Abstract

PURPOSE:To enable accurate measurement without being under the effect of environmental temp. at the time of measurement, by reading a correction level corresponding to a change in environmental temp. preliminarily stored in a memory part and correcting the signal level of a measuring object on the basis of said correction level. CONSTITUTION:A black body signal level detection circuit 12 extracting both signals of a first black body 9 and a second black body 10 to detect the level difference between both signals, a memory part 13 and a correction circuit 14 are provided. The correction signal corresponding to the detection signal level difference between the black bodies 9, 10 generated by the change of environmental temp. is preliminarily stored in the memory part 13. Scanning is repeatedly performed in series in the order of the black body 9, the black body 10 and a measuring object 1 and the detection level difference between the black body 9 and the black body 10 is detected at every repeated cycle to be stored in the memory part 13 and the correction signal corresponding to the detection level difference stored in the memory part 13 is read to be outputted to the circuit 14. The signal level of the object 1 is corrected on the basis of the correction signal in the circuit 14 to correct the measuring error of the object 1 generated by environmental temp.

Description

[Detailed Description of the Invention] [Summary] This is an infrared thermometer that detects the temperature difference between two black bodies having a predetermined temperature difference and inputs the detected temperature difference to a memory unit, which is stored in advance in the memory unit. The structure is configured to read out the correction temperature value of the detected temperature that changes in response to the environmental temperature at the time of measurement, and correct the detected temperature of the measured object, so that it is possible to accurately measure the measured object without being affected by the environmental temperature at the time of measurement. It enables temperature measurement.

[Industrial application field]

The present invention relates to an infrared thermometer, and more particularly to an infrared thermometer that has been improved so that it can accurately measure the temperature of an object without being affected by the environmental temperature at the time of measurement.

Infrared thermometers are widely used in the industrial and medical fields to measure the temperature of objects over a distance and changes in the temperature of the human body.

An infrared thermometer uses an infrared detector to detect the amount of infrared rays from a reference black body that generates a specified temperature and the amount of infrared rays from the object to be measured, converting them into electrical signals, and then converting the electrical signal level of the reference black body to the specified temperature. This infrared thermometer converts and displays the temperature of the object based on the difference between the two electrical signal levels.This infrared thermometer detects changes in the amount of infrared rays emitted from the casing as the environmental temperature changes during measurement. Due to changes in the amount of radiant light from each component of the optical system, the amount of stray light incident on the infrared #IA detector increases or decreases, and the converted electrical signal level of the infrared detector fluctuates. It was found that the temperature of the reference black body and the electrical signal level difference between the reference black body and the measurement object fluctuated, making accurate temperature measurement impossible.

Therefore, there has been a demand for an infrared thermometer that can accurately measure the salinity a1 of an object without being affected by the environmental temperature at the time of measurement.

[Conventional technology]

Figure 3 is a block diagram of a conventional infrared thermometer, which includes a reference blackbody 2 that generates a specified temperature, a measuring object 1, and a reference blackbody 2.
A switching unit 8 is provided for controlling the switching unit 8 to alternately detect the infrared rays emitted from the object 1 and the group I-1! A scanning mirror 3-1 that sequentially scans the black body 2 and captures both infrared rays, a condensing system 3-2 that collects and filters the captured infrared rays, and guides them to the infrared detector 4, and a filter 3.
-4 and scanning optical system 3 consisting of lens 3-3.3-5.
It is equipped with

Further, an infrared detector 4 converts the infrared rays of the reference black body 2 and the measurement object 1 captured by the scanning optical system 3 into electrical signals, an amplifier 5 that amplifies both signals converted by the infrared detector 4, and an amplifier 5. A clamp circuit 6 clamps both alternating current signals output from 5 at the signal level of the reference horse body 2 and detects the level difference between the two signals, and a specified temperature of the reference black body 2 clamped by the clamp circuit 6 is used as a reference. The structure includes a temperature display section 7 that converts and displays the temperature of the object to be measured based on the detected level difference.

The operation will be explained with reference to the signal waveform diagram in FIG. 4 and the characteristic diagram of the infrared detector in FIG. 5.

The scanning mirror 3-1 is controlled by a switching signal AI having a constant period shown in FIG. 4A output from the switching unit 8, and alternately switches between the measurement object 1 and the reference black body 2 as shown in FIG. 4B. The infrared radiation emitted from both is captured by scanning, and the condensing system 3-2,
It is output to the infrared detector 4 via the filter 3-4# and lens 3-3.3-5.

As shown in the characteristic diagram of FIG.
2, and AC amplify it to a predetermined voltage via the amplifier circuit 5 and output it to the clamp circuit 6.

The clamp circuit 6 receives the input ν as shown in FIG. 4C.
It clamps at the level of the two signals, detects the level difference ΔV between the v2 signal and the v1 signal, and outputs it to the temperature display section 7.

The temperature display unit 7 uses the v2 signal level as the specified temperature of the reference black body, converts the level difference ΔV between both signals, and displays the temperature of the measured object.

[Problem that the invention seeks to solve]

In this conventional temperature d11 method, if there is a change in the environmental temperature at the time of measurement, changes in the infrared radiation from the housing or changes in the infrared radiation generated from the lenses and filters of the scanning optical system will cause the infrared radiation to enter the infrared detector. The amount of stray light changes, and the fifth
The converted signals v1 and v2 of the measurement object 1 and the reference black body 2 vary depending on the detector characteristics shown in the figure, and the signal level difference ΔV between them also varies accordingly.

Therefore, there is a problem in that the level difference ΔV between the two signals set at the start of measurement changes, and an error occurs in the measured temperature of the measurement object 1.

The present invention was created in view of these points, and an object of the present invention is to provide an infrared thermometer that can accurately measure temperature without affecting the environmental temperature at the time of measurement.

[Means for solving problems]

FIG. 1 is a block diagram of an infrared thermometer according to the present invention, which is a conventional infrared thermometer including a first black body 9 and a second black body 10 having a predetermined temperature difference, and a measuring object 1. and the first
A switching unit 11 is provided to sequentially switch and detect infrared rays emitted from the black body 9 and the second black body 10.

Also, from the output signal of the amplifier 5, the first horse body and the second horse body are detected.
A black body signal level detection circuit 12 extracts both signals of the black body and detects a level difference between the two signals, and a temperature correction level stored in advance is output based on the detection level difference between the black body signal level detection circuit 12. The temperature correction level output from the memory section 13 is used to correct the signal level of the measurement object 1 outputted from the amplifier 5.

[Effect]

The memory unit 13 stores in advance a correction signal corresponding to a detection signal level difference between the first and second black bodies that occurs due to a change in environmental temperature.

First blackbody9. Second blackbody 10. Scanning is repeated in series in the order of the measurement object 1, and the first black body 9 is scanned at each repetition period.
The detection signal level difference between the second black body 10 and the second black body 10 is detected and inputted to the memory section 13, and a correction signal corresponding to the detection level difference stored in the memory section 13 is read out and corrected by the correction circuit 1.
4, and the correction circuit 14 corrects the signal level of the measurement object 1 with a correction signal to correct the measurement error of the measurement object 1 caused by the environmental temperature.

In the present invention, by correcting the signal of the measuring object with the correction signal corresponding to the change in the environmental temperature stored in the memory section 13, the temperature of the measuring object 1 can be accurately measured without being affected by the environmental temperature. becomes possible.

〔Example〕

FIG. 1 is a block diagram of an infrared thermometer according to an embodiment of the present invention, and the same parts as in FIG. 3 are designated by the same symbols.

The infrared thermometer of this embodiment is the same as the conventional infrared thermometer shown in FIG. A switching unit 11 is provided to sequentially switch and detect infrared rays emitted from the black body 9 and the second black body 10.

Also, from the output signal of the amplifier 5, the first black body and the second black body are detected.
A black body signal level detection circuit 12 extracts both signals of the horse body and detects a level difference between both signals, and outputs a pre-stored correction signal based on the detection level difference between the black body signal level detection circuit 12. The configuration includes a memory section 13 and a correction circuit 14 that corrects the signal level of the measurement object l output from the amplifier 5 using the correction signal output from the memory section 13.

The operation will be explained with reference to the signal waveform diagram in FIG.

The switching signal 01. which is output from the switching unit 11 and has a constant interval shown in the second diagram. D2. D3 controls the scanning optical system 3, and the first black body 9. The second black body 10 and the measurement object 1 are repeatedly scanned in this order, and the infrared rays radiated from the three bodies are sequentially captured and output to the infrared detector 4.

The infrared detector 4 converts the infrared rays inputted sequentially from the three sources into electrical signals, which are then amplified by the amplifier 5 to produce a signal El from the first black body 1 and a signal El from the second black body 10 as shown in FIG. signal E
2 and the signal of measurement object 1 [! 3 is formed and output.

In addition, the black body signal level detection circuit 12 extracts the signals El and 82 of the first black body 9 and the second black body 10 output from the amplifier 5, as shown in FIG. The level difference Δν between the El signal and the E2 signal is detected and output to the memory section 13.

The memory section 13 contains E, which is generated due to changes in environmental temperature, in advance.
A correction signal corresponding to a variation in the level difference ΔV between the 1 signal and the 1!2 signal is stored.

The memory unit 13 stores the El signal and [!
A correction signal (Gl, G2 in FIG. 2G) corresponding to the level difference ΔV between the two signals is read out and output to the correction circuit 14.

The correction circuit 14 corrects the level of the signal E3 of the measurement object L for each period outputted from the amplifier 5 with the correction signals Gl and G2 for each period outputted from the memory section 13, and outputs the signal E3 from the amplifier 5 to the clamp circuit 6.
Output to.

As shown in FIG. 2H, the clamp circuit 6 clamps the signal of either the first black body 9 or the second black body 10, for example, the E2 signal level of the second black body 10, and outputs the E2 signal. Difference Δv1 between the level and the old signal level of the corrected measurement object 1
is detected and output to the temperature display section 7.

The temperature display section 7 displays the temperature of the measured object based on the level difference Δv1.

〔Effect of the invention〕

As explained above, according to the present invention, the correction level corresponding to the change in the environmental temperature stored in the memory section is read out, and the signal level of the measurement object is determined using the +E level. #
By using iE, it is possible to accurately measure the temperature of an object without being affected by the environmental temperature.

[Brief explanation of drawings]

Figure 1 is a block diagram of an infrared thermometer according to an embodiment of the present invention, Figure 2 is a signal waveform diagram for explaining the operation of an actual example, and Figure 3 is a block diagram of an infrared thermometer according to an embodiment of the present invention.
Figure 4 is a block diagram of a conventional infrared thermometer, Figure 4 is a signal waveform diagram for explaining the operation of the conventional infrared thermometer, and Figure 5 is a characteristic diagram of an infrared detector. In the figure, 1 is the measurement object, 2 is the reference horse body, 3 is the scanning optical system, 3-1 is the scanning mirror, 3-2 is the condensing system, 3-3.3-
5 is a lens, 3-4 is a filter, 4 is an infrared detector, 5
is an amplifier, 6 is a clamp circuit, 7 is a temperature display section, 8,1
1 is a switching unit, 9 is a first black body, 1() is a second black body, 1
2 is a black body signal level detection circuit, 13 is a memory section, and 14 is a correction circuit. 11J LL り 工（i燵J
P/) I7Lnu KL#y>7- Hiv7m Figure 3 Housha F-? 7-n 硅 #6Qtj し た ↑ yo estate, ν's signal i-shaped times red 7 toki shuji p, %, ≠ Potato / L main G ] w 5 Fig. 4

Claims (1)

[Claims] An infrared thermometer that measures the temperature of an object by detecting infrared rays from the object, comprising first and second black bodies (9, 10) that generate a predetermined temperature difference, and detecting the two black bodies. a blackbody signal level detection circuit (12) that extracts a signal and detects a level difference between both signals;
a memory unit (13) that inputs the output of 12) and outputs a temperature correction signal stored in advance corresponding to the output;
An infrared thermometer comprising a correction circuit (14) for correcting the detection signal of the object based on the output temperature correction signal of the memory section (13).