JPH01102328A - Measuring apparatus of temperature by infrared ray - Google Patents

Abstract

PURPOSE:To restrict an unnecessary disturbance light entering a detector while preventing the lowering of sensitivity of the detector and the effect of the disturbance light thereon and thereby to enable the stable measurement of temperature, by a construction wherein a light quantity restricting means constituted by a concave mirror is disposed in the visual field of a detecting element. CONSTITUTION:The surface 25 of a light quantity restricting means 22 facing a detector 7 is specular, and therefore the self-emission of an infrared energy from the means 22 is very small. At the same time, the means 22 is disposed so that the center of curvature of a concave mirror 24 is located in the position of a detecting element 16, and therefore only an infrared energy self-emitted from the element 16 is reflected by the concave mirror 24 and made to enter the element 16 again, wile infrared energies other than the above falling from outside and reflected by the specular surface 25 are not made to enter the element 16. Since the element 16 is cooled down, the infrared energy from the element 16 is weak, and the infrared energy reflected by the concave mirror 24 and made to enter the element 16 again is small. Accordingly, a disturbance light occurring in a part 26 is so small as to be negligible, and thus the stable measurement of temperature is enabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an infrared temperature measuring device that measures the temperature of an object by detecting infrared rays emitted from an object depending on its temperature, and particularly to an infrared detection device for the infrared temperature measuring device. Regarding the structure of the department.

[Summary of the invention]

The present invention provides an infrared temperature measuring device equipped with a cooled infrared detecting element, in which a light amount diaphragm means made of a concave mirror having an infrared transmitting hole in the center is disposed within the field of view of the infrared detecting element. This allows stable temperature measurement over a range of temperatures.

[Conventional technology]

2. Description of the Related Art Conventionally, an infrared measuring device has been proposed that detects infrared energy naturally radiated from the surface of an object to be measured and displays the temperature distribution of the object as a color image or a black and white image corresponding to the temperature. That is, as shown in FIG. 2, a predetermined range of the object to be measured (1), for example, the region to be measured (2), is scanned by the X-scanning mirror (mirror that scans in the X-axis direction) (3) and the optical scanning system (5). By scanning with the Y-scanning mirror (mirror that scans in the Y-axis direction) (4),
The infrared rays obtained corresponding to each measurement point in the measurement area (2) are sequentially focused by the objective lens (6) and sent to the infrared detector (7).
is incident on the

The incident infrared energy is converted into an electric signal proportional to the temperature by an infrared detector (7), and is supplied to a display section (8) to display the temperature distribution of the measurement area (2) as a color image or a black and white image. Ru.

As shown in Fig. 3, the infrared detector (7) had an inner wall (11) and an outer wall (12), and a vacuum region (13) was formed between the inner and outer walls (11) and (12). Container (14
) into a cooling medium such as liquid nitrogen (-196°C) (15)
The infrared detection element (16) is arranged so as to be in contact with the inner wall (11) in the vacuum region (13). An infrared transmitting window (17) is provided in a portion of the outer wall (12) facing the detection element (16). Furthermore, this detector (7) has a viewing angle θ in order to reduce the fluctuation of photons incident on the detection element (16) from angles other than the viewing angle θ (an important factor of noise in the detector (7)). A cold shield (i.e., a shield body cooled with liquid nitrogen (15)) (18) made of, for example, carbon, Kovar, etc. is provided. This detector (7) has a cold shield (
18) makes it possible to reduce noise. At this time, the improvement rate A of the detection rate of the detection element (16) is expressed by.

By the way, the viewing angle θ is changed by the cold shield (18).
If θ is made smaller, the noise becomes smaller, but the amount of light incident on the detector (7) increases as θ becomes larger, so in the case of an infrared temperature measuring device, θ cannot be made smaller when measuring low temperatures.

On the other hand, with a general-purpose infrared temperature measuring device that can measure from low to high temperatures, when measuring low temperatures, it is used at the viewing angle θ determined by the cold shield (18) of the detector (7); Since energy is proportional to the fourth power of temperature, the detector (7) becomes saturated and cannot be measured. For this reason, in the case of high temperature measurement, the detector (
7), a flat light amount diaphragm plate (19) is separately arranged in front of the light source, and the viewing angle is equivalently reduced, that is, the viewing angle is set to θ', and the amount of light is controlled and measured. ``Generally, in an object, the sum of the emissivity and reflectance of infrared energy is l. The conventional light aperture slope (19) is made of a material with low reflectance (and therefore high emissivity).

(Problem to be Solved by the Invention) However, in the case of FIG. Since the temperature is the same as the air temperature, infrared energy emitted from this light aperture plate (19) due to changes in outside temperature, that is, infrared energy unnecessary for measurement (2
0) enters the detector (7) and becomes a disturbance. For this reason,
The output signal of the detection element (16) is obtained by adding the signal caused by this disturbance light to the signal caused by the incident light corresponding to θ' that should be measured, and varies depending on the intensity of the disturbance light based on fluctuations in the outside temperature. Temperature measurement became unstable.

In view of the above-mentioned points, the present invention is an infrared temperature sensor that limits the incidence of unnecessary disturbance light on the detector and enables stable temperature measurement over a wide temperature range without the influence of disturbance light. The present invention provides a measuring device.

[Means for solving problems]

The present invention provides an infrared temperature measuring device including a detector (7) in which the infrared detecting element (16) is cooled by liquid nitrogen, electronic cooling, etc. Within the field of view of the detection element (16), a light amount diaphragm means (22) consisting of a concave mirror having an infrared transmission hole (23) in the center
This light amount diaphragm means (22) is arranged so that its concave mirror (24) faces the detection element (16),
The concave mirror (24) is arranged so that the center of curvature is approximately at the position of the detection element (16). This light amount diaphragm means (22) made of a concave mirror is appropriately placed in front of the detector (7) in the case of high temperature measurement.

[Effect]

In the above configuration, the light amount diaphragm means (2
2) is arranged. The detector (
Since the surface (25) facing 7) is a mirror surface, the self-emission of infrared energy from the light amount diaphragm means (22) is extremely small, being about 5/100 of that of a conventional light amount diaphragm plate.

At the same time, the light aperture means (22) is arranged so that the center of curvature of the concave mirror (24) is at the position of the detection element (16), so that only the infrared energy self-emitted from the detection element (16) is reflected by the concave mirror. Infrared energy that is incident from the outside and reflected by the mirror surface (25) is not incident on the detection element (16). Since the detection element (16) is cooled, the infrared energy from the detection element (16) is extremely weak, so it is reflected by the concave mirror and returned to the detection element (16).
The infrared energy incident on 6) is negligibly small. That is, this configuration apparently has the same effect as providing a cold shield with a viewing angle θ'.

Therefore, the disturbance light generated in the shaded area (26) in FIG. 1 becomes negligible, making stable temperature measurement possible.

〔Example〕

Hereinafter, an embodiment of the infrared temperature measuring device according to the present invention will be described using FIG. Note that FIG. 1 shows only the detection section of the infrared temperature measuring device.

In this example, as explained in FIG. 2, a predetermined measurement area (2) of the measurement object +11 is scanned by the Then, the infrared energy obtained corresponding to each measurement point in the measurement area (2) is sequentially incident on the infrared detector'a (7) through the objective lens (6), and the infrared detector (7) detects an electric signal. and supplies it to the display section (8),
) is configured to display the temperature distribution as a color image or a black and white image.

In this example, the infrared detection section is particularly configured as shown in FIG. That is, (7) is an infrared detector, (
22) shows a light amount diaphragm means arranged in front of this detector (7). The detector (7) is located on the inner wall (11) and outer wall (12).
, and a vacuum area (
13) is filled with a cooling medium such as liquid nitrogen (-196°C <15), and the vacuum area (13) is
) The infrared detection element (1) is in contact with the inner wall (11) in
6), a cold shield (18) is provided to surround the detection element (16) so as to provide a viewing angle of θ, and an infrared transmitting window is provided in the part of the outer wall (12) facing the detection element (16). (17) is provided and configured. On the other hand, the light amount diaphragm means (22) consists of a concave mirror (24) with an infrared transmission hole (23) in the center, and the mirror surface (25) is the detector (24).
window (1) of the detector (7) so that the center of curvature of the concave mirror (24) is approximately at the position of the detection element (16).
7). In this case, the concave mirror (
The transmission hole (23) of 24) is within the field of view of the detection element (16) regulated by the cold shield (18), that is, the viewing angle θ
exists within. The mirror surface (25) of the concave mirror (24) is, for example, A
It can be formed using a vapor deposited film of I, Au, or the like.

According to such a configuration, the emissivity of infrared energy can be easily set to about 0.05 on the mirror surface (25) of the concave mirror (24) constituting the light amount diaphragm (22), so that the concave mirror (24) The self-emission from the light source is about 5/100 of that of the conventional light aperture plate (19) (see Figure 4). At the same time, in the shaded area (26), only the radiation energy from the cooled detection element (16) is transmitted to the concave surface of 1 m (26).
4) is reflected by the mirror surface (25) and returns to the detection element (16).
Even if other external radiant energy is reflected by the mirror surface (25), it will not be incident on the detection element (16). Therefore, apparently the same effect as arranging a cold shield with a viewing angle θ' is produced. Therefore, the shaded area (26
) will be minimized to the point where it can be ignored. Therefore, the concave surface #14 (2) has an infrared transmission hole (23) in the center.
By using 4) as the light amount diaphragm means (22), temperature measurements over a wide range from low to high temperatures can be stably performed.

The light amount diaphragm means (22) is provided for high-temperature measurement, but is not provided for low-temperature measurement when infrared energy is incident within the range of θ.

〔Effect of the invention〕

According to the present invention, in an infrared temperature measuring device equipped with a detector in which an infrared detection element is cooled, by arranging a light amount diaphragm means made of a concave mirror having an infrared transmission hole in the center within the field of view of the detection element, It is possible to limit unnecessary disturbance light incident on the detector and to stably measure temperature by eliminating the effects of low sensitivity of the detector and disturbance light in temperature measurement over a wide temperature range.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the detection unit of the infrared temperature measuring device according to the present invention, FIG. 2 is a block diagram of the infrared temperature measuring device used to explain the present invention, and FIGS. 3 and 4 are respectively conventional infrared temperature measuring devices. FIG. 3 is a cross-sectional view of a detection section of the measuring device. (2) is a region to be measured, (7) is a detector, (16) is a detection element, and (22) is a light amount diaphragm means.

Claims (1)

[Scope of Claims] An infrared temperature measuring device equipped with a detector in which an infrared detection element is cooled, wherein a light amount diaphragm means made of a concave mirror having an infrared transmission hole in the center is disposed within the field of view of the infrared detection element. An infrared temperature measuring device consisting of: