JPH02228529A - Reference temperature source apparatus - Google Patents

Abstract

PURPOSE:To enable accurate measurement with one black body by developing a specified temperature difference between one end and the other end of a metal body while a plurality of black body sections are formed therebetween. CONSTITUTION:When one end 21a of a metal body 21 is cooled with an electronic cooling element 23 while the other end 21b thereof is heated with a heater 24, a temperature difference is developed between one end 21a and the other end 21b thereof, which in turn generates a temperature gradient between one end 21a and the other end 21b thereof 21. Hence, a radiation energy level varies among black body sections 22 to make them as a reference temperature source with a temperature difference. Moreover, the black body sections can produce any fine temperature difference as desired by varying a position where they are set and a shape or the like of the metal body 21. Thus, a photographing is performed directly with a thermography device using the black body section 22 as reference temperature source thereby enabling direct evaluation with only one black body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reference temperature source device suitable for use in calibrating radiation thermometers, calibrating thermography devices, and measuring accuracy.

[Summary of the invention]

The present invention relates to a reference temperature source device suitable for use in calibrating a radiation thermometer or measuring the accuracy of a thermography device. By forming a plurality of black body parts between one end and the other end of the metal body, it is possible to more accurately calibrate and measure the accuracy of the thermography apparatus.

[Conventional technology]

Conventionally, radiation thermometers that measure temperature by detecting infrared energy emitted from the surface of a measured object are calibrated using a blackbody as a reference temperature source at the time of shipment from the manufacturer. As shown in Figure 6, this blackbody is composed of a blackbody furnace (1) and a temperature control section (2), and the heating element of the blackbody furnace (1) has two platinum resistance wires (JIS , 5
(3) and (4) are embedded, one platinum resistance wire (3) is for temperature control and the other platinum resistance wire (4) is embedded.
are used for temperature detection.

A platinum resistance wire (3) for temperature control forms one side of the bridge, changes the resistance value of the other side, and sets the target temperature. The unbalanced voltage of this bridge circuit (5) is converted into an amplifier circuit (6).
), the signal is synchronously detected by the synchronous detection circuit (7), and this synchronous detection signal operates the phase control circuit (8) to increase or decrease the current flowing to the heater (9) in the blackbody furnace (1). temperature to stabilize it at the target temperature.

Also, set the dial of the variable resistor (10) so that the resistance value is the same as the platinum resistor for temperature detection, and when the output of the comparator (11) becomes zero, the indicator meter (12) will read zero. This variable resistor (10) is adjusted to show
The temperature of the black body can be determined accurately by reading the dial.

Once the temperature of the black body is determined, the value of infrared energy emitted from this black body is also determined, and by pointing the radiation thermometer at this black body, the radiation thermometer is calibrated using this black body as a reference temperature source. be able to.

By the way, while a radiation thermometer is used to measure the temperature of a measured object, the principle is the same, but a radiation thermometer measures the temperature distribution of the measured object and produces a color or monochrome image corresponding to the temperature. There is a thermography device that displays as

In this thermography device, the minimum detectable temperature difference (Nois) is used as a measure of its accuracy (sensitivity).
e Equivalent Temperature D
difference: NETD).

In other words, since the purpose of a thermography device is to measure temperature distribution, it is important to be able to distinguish between temperature differences and to what extent. NETD can equivalently convert the noise voltage contained in the temperature signal of a radiation thermometer into a temperature difference. The smaller the NETD, the better the sensitivity regarding temperature distribution measurement.

As an example of how to measure NETD, a standard furnace (standard furnace A, standard furnace B) consisting of two black bodies with different temperatures is imaged using an imaging device (15) (see Figure 7), and the signal waveform at that time is (See Figure 8) with a cathode ray tube oscilloscope (16
), and NETD is calculated using the following equation (1). In addition, in the case of a medical infrared imaging device, the temperature TA of standard furnace A is 30 cm, and the temperature T of standard furnace B is 35 ± 1'.
Let it be C.

Here, NETD: Minimum detectable temperature difference (°C) T p,,
T m : Temperature of standard furnace A and standard furnace B (°C) S; Voltage difference between signals of standard furnace A and standard furnace B (V) N1. : P-P value (V) of noise voltage [Problem to be solved by the invention] However, in the conventional NETD measurement method,
Since two black bodies are used, there are disadvantages such as increase in size and cost.Also, even if a platinum resistance wire for temperature detection is used for the black bodies, the accuracy of which is 0.15 class. However, due to the variation, it is difficult to realize two black bodies with a minute temperature difference such as 0.1° C. Therefore, indirect evaluation is performed using the method described above.

In view of the above, an object of the present invention is to propose a reference temperature source device that can perform accurate precision measurements using a single black body.

[Means to solve the problem]

The reference temperature source device of the present invention is, for example, as shown in FIG.
The metal body (21) is made to have a predetermined temperature difference between one end (21a) and the other end (21b), and
1) A plurality of blackbody portions (22) are formed between one end (21a) and the other end (21b).

[Function] According to the present invention, one end (21a) of the metal body (21)
) and the other end (21b), a predetermined temperature gradient occurs between the one end (21a) and the other end (21b) of this metal body (21).
A plurality of black body parts (2) formed at appropriate locations between
2) serves as a reference temperature source with a predetermined minute temperature difference from each other, and by directly imaging the reference temperature source with a minute temperature difference, it is possible to directly evaluate how much temperature difference can be discriminated, which improves the calibration and accuracy of thermography equipment. Accurately one measurement can be performed with one blackbody.

〔Example〕

Hereinafter, one embodiment of the reference temperature source device of the present invention will be described with reference to FIGS. 1 to 4.

In FIGS. 1 to 4, the same components as those of the conventional system are given the same reference numerals, and detailed explanation thereof will be omitted.

(21) is a metal hexagonal prism as a metal body, for example copper.

Made of brass etc., one end (21a) and the other end (21b)
An electronic cooling element (23) as a cooling means is provided on one end (21a) side, and a heater (such as a nichrome wire) as a heating means is provided on the other end (21b) side so that a predetermined temperature difference between 24) is provided. Then, a metal hexagonal column (2
1) A plurality of black body portions (22) are provided at appropriate intervals between one end (21a) and the other end (21b).

Although this black body portion (22) is formed by applying a paint with high emissivity, it may also be formed by providing holes to increase the effective emissivity. In addition, (25) is the resistance temperature detector on one end (21a) side, and (26) is the other end (21b).
The temperature measuring resistors on the sides are shown respectively.

In such a black body as a reference temperature source device, one end (21a) of the metal hexagonal column (21) is connected to the electronic cooling element (2).
3) and then heat the other end (21b) with the heater (24), a temperature difference will be created between one end (21a) and the other end (21b), and one end (21a) of the metal hexagonal column (21) will be cooled. ) and the other end (21b). Therefore, the amount of radiant energy in each black body part (22) differs as shown in FIG. 4, and each black body part (22) serves as a reference temperature source with a temperature difference. Moreover, by changing the position of the black body part (22), the shape of the metal hexagonal column (21), etc., each black body part (22) can have an arbitrary minute temperature difference.

Therefore, if the black body part (22) with such minute temperature difference is directly imaged with a thermography device as a reference temperature source, it is possible to directly evaluate how much temperature difference can be discriminated with a single black body, and the temperature difference of the thermography device can be directly evaluated. Accuracy measurement can be performed extremely easily and accurately using a miniaturized device. Further, if such a black body is used as a reference temperature source of a radiation thermometer, multiple point measurements can be easily performed instead of the conventional single point measurement, and the radiation thermometer can be calibrated more accurately.

FIG. 5 shows another embodiment of the present invention, and the difference from the above embodiment is that an expensive cooling device such as an electronic cooling element is not used, and a fan (not shown) is used as the cooling means. ), etc., and one end is kept at around ambient temperature by means of heat dissipation means (28).

A blackbody constructed in this manner also provides the same effects as those of the above-mentioned embodiments.

In the above embodiment, a metal hexagonal column was used as the metal body, but a metal plate may also be used.

Furthermore, the present invention is not limited to the above-mentioned embodiments,
Of course, various configurations are possible without departing from the gist of the present invention.

It is evening.

[Effects of the Invention] As described above, according to the present invention, there is an advantage that accuracy measurement of a thermography apparatus can be performed extremely accurately using a single black body.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the main parts of an embodiment of the reference temperature source device of the present invention, Fig. 2 is a configuration diagram of one side (low temperature side) of Fig. 1, and Fig. 3 is the other side of Fig. 1. (high temperature side); Figure 4 is a diagram showing the relationship between the amount of radiant energy and the position of each black body;
Figure 6 is an overall configuration diagram showing another embodiment of the present invention, Figure 6 is an overall configuration diagram of a conventional black body, Figure 7 is a schematic configuration diagram of accuracy measurement of a conventional thermography device, and Figure 8 is a diagram showing the overall configuration of a conventional black body. FIG. 2 is a diagram showing the signals obtained by the illustrated device;

Claims (1)

[Claims] A reference temperature source device characterized in that a predetermined temperature difference exists between one end and the other end of the metal body, and a plurality of black body portions are formed between the one end and the other end of the metal body. .