JP2615913B2 - Infrared optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] An optical device used in an infrared imaging device, which aims to accurately measure a target object in a wide temperature measuring range, and has a lens for condensing infrared light as a component. An aperture for changing the amount of infrared light transmitted through the lens, and an infrared detector having a built-in detection element having a black body disposed therearound, wherein the detection element includes the infrared ray passing through the aperture and the black light. The components are sequentially arranged on a common optical axis so that only infrared rays radiated from the body and reflected on the surface of the diaphragm on the sensing element side are incident.

[Industrial applications]

 The present invention relates to an optical device used for an infrared imaging device.

Infrared imaging devices having a non-contact, real-time temperature measurement function using infrared rays are required to be versatile and highly accurate, and measures are also required for the optical system.

[Prior Art] FIG. 3 shows a conventional infrared optical device, wherein 1 is a lens, 2
Is an infrared detector, 21 is a detection element, 22 is a double tube container, 23 is a window, 24 is a cold door aperture, the container 22 is filled with liquid nitrogen (LN ₂ ), and the infrared detector 2 is Below zero 190
It has been cooled to about ° C.

By the way, in order to improve the measurement accuracy of the infrared optical device, it is possible to set the F value of the lens that matches the measurement temperature range (temperature measurement range) of the target object, and to set the amount of invalid background infrared light that enters from outside the lens. Needs to be reduced to reduce noise. The F value is the reciprocal of the aperture ratio, and the aperture ratio is the ratio between the lens diameter and the focal length. The smaller the F value, the more light is collected and brighter, and the larger the F value, the opposite. Is an exponent.

[Problems to be solved by the invention]

However, the viewing angle of the infrared detector 2 is determined by the detection element and the cold aperture, and the F angle corresponding thereto is determined.
Constituting an infrared optical device integrally with a lens having a value,
Only a target object within a certain limited temperature measurement range is detected. Therefore, in order to detect a target object having a wide temperature measurement range, many infrared optical devices having different temperature measurement ranges have been required. Otherwise, an accurate measured temperature of the target object cannot be obtained, such as an increase in noise due to the addition of the background light amount.

Further, when the amount of infrared light to be measured is very large, a method of measuring by increasing the F value through a normal diaphragm (blackened diaphragm for visible light) is used. Since the diaphragm emits or reflects effective infrared light outside the target object, there is a disadvantage in that when radiation or reflected light from the diaphragm is received, noise increases and sensitivity decreases.

The present invention solves such a problem and prevents an invalid infrared ray from being incident on the detecting element even when the F-number of the lens is changed by the aperture, thereby accurately measuring a target object in a wide temperature measuring range. It is an object of the present invention to propose an infrared optical device for the purpose.

[Means for solving the problem]

The problem is, as shown in FIG.
A lens 1 for condensing infrared light, a diaphragm 3 for changing the amount of infrared light transmitted through the lens, and an infrared detector 2 having a built-in detection element 21 having a black body 4 disposed therearound. Each element is placed on a common optical axis so that only infrared rays passing through the aperture 3 and infrared rays emitted from the black body 4 and reflected by the surface of the aperture 3 on the sensing element 21 side enter the aperture 21. This is solved by an infrared optical device which is arranged and arranged sequentially.

(Operation)

That is, according to the present invention, only the infrared light amount of the target object which has passed through only the through hole provided in the aperture 3 is detected by the detection element 21, and the infrared light amount of the invalid background is absorbed by the cooled black body 4. The surface 3 is so configured that it is reflected almost 100% and does not enter the detection element 21. That is, since the detecting element 21 is positioned so as to see the black body 4 by the surface reflection of the stop 3, infrared light does not enter the detecting element from the cooled black body 4, and the infrared light enters the surface of the stop 3 from other places. Approximately 100 other infrared rays
The configuration is such that only the amount of infrared light of the target object can be detected by the detection element without being reflected by% and entering the detection element. Thus, when the F-number is changed by the aperture 3, an infrared optical device for detecting a target object in a wide temperature measuring range without influence of an ineffective background infrared light amount can be obtained.

〔Example〕

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows an infrared optical device according to the present invention, wherein 1 is a lens, 2 is an infrared detector, 21 is a detecting element, 22 is a container, 23 is a window, 3 is an aperture, and 4 is a black body. As in the conventional device, the window 23 is made of germanium or silicon that transmits infrared light, the inside of the container 22 is filled with liquid nitrogen, and the 'slipper' surrounding the sensing element 21 which is one of the constitutions according to the present invention. The '-shaped black body 4 (made of carbon, for example) is also cooled to the same temperature, and the cooled black body has a large emissivity and absorbs all the incident infrared rays. On the other hand, the stop 3 has a surface that totally reflects infrared rays, has an emissivity of zero, and reflects approximately 100% of incident infrared rays. Further, the change in the hole diameter of the stop 3 is made to have the same variable structure as that of the visible light stop.

FIG. 2 illustrates the positional relationship between the detection element 21, the black body 4, and the stop 3. The detection element 21 is irradiated with infrared rays of a target object to be detected from the passage hole 3H of the stop 3. The cooled black body 4 has a surface that absorbs all the infrared rays of the ineffective background and totally reflects the aperture infrared rays facing the inactive infrared rays. Black body 4
And irradiation light and reflected light are indicated by arrows. Therefore, the infrared rays of the invalid background are blocked, and only the amount of infrared rays of the target object irradiates the detecting element. Then, by changing the diameter of the passage hole 3H provided in the diaphragm 3, the F value is changed, and the temperature of the target object in a wide temperature measurement range can be accurately detected.

When the aperture diameter of the aperture is changed in the optical system provided with the aperture as described above, the amount of light incident on the detection element naturally changes. For this reason, a device equipped with a means for adjusting the amplification degree to an appropriate value as necessary to keep the signal within the dynamic range of the detection system that amplifies and processes the photoelectric conversion signal such as an infrared radiometer or infrared imaging device And

〔The invention's effect〕

As is clear from the above description, the infrared optical device according to the present invention is applicable to a target object having a wide temperature measurement range, is versatile, and has a large effect of being able to measure with high accuracy.

[Brief description of the drawings]

 FIG. 1 is an infrared optical device according to the present invention, FIG. 2 is a diagram showing a positional relationship between a detecting element, a black body, and an aperture, and FIG. 3 is a conventional infrared optical device. In the figure, 1 is a lens, 2 is an infrared detector, 3 is an aperture, 4 is a black body, 3H is a passage hole of the aperture 3, 21 is a detection element, 22 is a container, 23 is a window, and 24 is a cold aperture. I have.

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Kenji Awamoto 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited

Claims (1)

(57) [Claims] 1. An infrared optical device comprising: a lens for condensing infrared rays; and a detector having a detecting element for receiving the infrared rays.
A stop having a reflecting surface formed on the surface on the detector side is disposed between the lens and the detector, and a black body is disposed around the detecting element in the detector. An infrared optical device, wherein only infrared rays that have passed through the aperture and infrared rays emitted from the black body and reflected by a surface of the aperture on the detection element side are incident.