JPH07218816A - Focus adjusting device for infrared image pickup device - Google Patents

Abstract

PURPOSE:To correct the movement of the focus due to any temperature change by providing a plane plate window on the object side of an objective optical system perpendicularly to the optical axis and additionally arranging a relay optical system and a two-dimensional detector for objective optical system adjustment on the same plane as a two-dimensional image detector and additionally arranging a light source between the objective optical system and the relay optical system. CONSTITUTION:The position of a relay optical system 3 in the direction of the optical axis is so adjusted that the peak of the output of a two-dimensional detector 6 for relay optical system adjustment, which is obtained at the time when infrared light emitted from a light source 5 arrives at this two-dimensional detector 6 through a relay optical system 3, is maximum. The position of an objective optical system 2 in the direction of the optical axis is so adjusted that the peak value of the output of a two-dimensional detector 7 for objective optical system adjustment, which is obtained at the time when infrared light emitted from the light source 5 passes the objective optical system 2 and is partially reflected by a plane plate window 1 and arrives at this two-dimensional detector 7 through the objective optical system 2 and the relay optical system 3, is maximum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting device for an infrared imager for detecting a target in a fire control system, for example.

[0002]

2. Description of the Related Art In general, an infrared imager for detecting a target in a fire control system needs to always focus the imager at infinity regardless of the presence or absence of a target so that a distant target can be found. On the other hand, since the infrared imager is mounted on a ship or an aircraft, its ambient temperature may reach −50 to 70 ° C. At this time, the optical system in the infrared imager may change the refractive index or shape of the material due to temperature change. The focus position moves. As a result, in some cases, even if the focus of the infrared imaging device is at infinity, the focus may be deviated due to a temperature change over time.

Conventionally, a focus adjusting device as shown in FIG. 6 has been used for such a focus shift. In the figure, 2 is an objective optical system, 3 is a relay optical system, 4 is a two-dimensional image detector,
Reference numeral 8 is a processing device, 9 is a relay optical system optical axis direction moving mechanism control device, 10 is an objective optical system optical axis direction moving mechanism control device, 1
Reference numeral 1 is a relay optical system optical axis direction moving mechanism, 12 is an objective optical system optical axis direction moving mechanism, 13 is an optical axis, 18 is a memory, 19 is a relay optical system temperature sensor, and 20 is an objective optical system temperature sensor.

Next, the operation will be described. The amount of movement of the focal position due to temperature change is stored in the memory 18 as data by calculation or test in advance. The processing device 8 compares the temperature data from the objective optical system temperature sensor 20 and the relay optical system temperature sensor 19 installed in the vicinity of the objective optical system 2 and the relay optical system 3 with the data in the memory 18 and compares them with each other. Of the objective optical system 2 through the objective optical system optical axis direction moving mechanism controller 10 and the objective optical system optical axis direction moving mechanism 12, and also the relay optical system. A part or the whole of the relay optical system 3 is moved through the system optical axis direction moving mechanism control device 9 and the relay optical system optical axis direction moving mechanism 11, and as a result, focus adjustment is performed.

[0005]

Since the conventional focus adjusting device is constructed as described above, when the objective optical system 2 and the relay optical system 3 have a temperature distribution due to a sudden environmental temperature change, etc. There was a problem that the amount of focus movement could not be obtained correctly with the data stored in 18, and it could not function sufficiently.

The present invention has been made in order to obtain a focus adjusting device capable of correcting the focus movement due to any temperature change, instead of the conventional focus adjusting device having the above problems. Is.

[0007]

Embodiment 1 according to the present invention
The focus adjusting device has a flat window vertically installed on the object side of the objective optical system with respect to the optical axis, and a two-dimensional detector for adjusting the relay optical system and an objective optical system for adjusting the two-dimensional image on the same plane as the two-dimensional image detector. A dimension detector is arranged and a light source is arranged between the objective optical system and the relay optical system.

In the focus adjusting apparatus according to the second embodiment of the present invention, a flat window is installed on the object side of the objective optical system so that the incident angle is α with respect to the optical axis, and on the same plane as the two-dimensional image detector. 2 for adjusting the relay optical system at a position y1 from the optical axis
A two-dimensional detector and a two-dimensional detector for adjusting the objective optical system are arranged on the same plane at a distance y2 from the optical axis, and the two-dimensional detector is arranged at a distance x from the optical axis between the objective optical system and the relay optical system. A light source is arranged, and (7), (8), between α, x, y1 and y2.
It has the relationship of equation (9).

[0009]

[Equation 7]

[0010]

[Equation 8]

[0011]

[Equation 9]

In the focus adjusting apparatus of the third embodiment according to the present invention, a flat plate window is vertically installed on the object side of the objective optical system with respect to the optical axis, and for adjusting the relay optical system other than the image detecting area of the two-dimensional image detector. The two-dimensional area and the two-dimensional area for adjusting the objective optical system are set, and the light source is arranged between the objective optical system and the relay optical system.

In the focus adjusting apparatus according to the fourth embodiment of the present invention, a flat window is installed on the object side of the objective optical system so that the incident angle is α with respect to the optical axis, and the image is detected in the two-dimensional image detector. Outside the area, a two-dimensional area for adjusting the relay optical system is set at a distance y1 from the optical axis, and a two-dimensional area for adjusting the objective optical system is set at a distance x2 from the optical axis at a distance y2. Distance x from optical axis between optical system and relay optical system
Place the light source at the position of and place (1
It has the relations of 0), (11), and (12).

[0014]

[Equation 10]

[0015]

[Equation 11]

[0016]

[Equation 12]

[0017]

The focus adjusting devices according to the first and second embodiments of the present invention are relay optics obtained when infrared light emitted from a light source reaches a relay optical system adjusting two-dimensional detector through a relay optical system. The position of the relay optical system in the optical axis direction is adjusted so that the peak of the output of the two-dimensional detector for system adjustment is maximized, and the infrared light emitted from the light source passes through the objective optical system and passes through a flat window. The peak value of the output of the objective optical system adjusting two-dimensional detector obtained when it reaches the objective optical system adjusting two-dimensional detector through the objective optical system and the relay optical system is maximized. In addition, the position of the objective optical system in the optical axis direction is adjusted.

The focus adjusting devices of Embodiments 3 and 4 according to the present invention are relay optical systems obtained when infrared light emitted from a light source reaches a relay optical system adjusting two-dimensional area through the relay optical system. The position of the relay optical system in the optical axis direction is adjusted so that the output peak in the adjustment two-dimensional area is maximized, and the infrared light emitted from the light source passes through the objective optical system and is partially reflected by the flat window. In addition, the objective optical system is designed to maximize the peak value of the output of the objective optical system adjusting two-dimensional area obtained when reaching the objective optical system adjusting two-dimensional area through the objective optical system and the relay optical system. The position in the optical axis direction of is adjusted.

[0019]

【Example】

Embodiment 1 A conceptual diagram of a focus adjustment device according to the present invention will be described with reference to FIG. In the figure, 1 is a flat window, 2 is an objective optical system, 3 is a relay optical system, 4 is a two-dimensional image detector, 5 is a light source, 6 is a two-dimensional detector for adjusting the relay optical system, and 7 is for adjusting the objective optical system. The two-dimensional detector, 13 is the optical axis.

Next, the operation will be described. The infrared light emitted from the light source 5 to the right side in the figure passes through the relay optical system 3
The light is focused on a position opposite to the light source 5 with respect to the optical axis on the same plane as the three-dimensional image detector 4. When the two-dimensional detector 6 for adjusting the relay optical system is installed at this position, its output becomes maximum. Further, when the parallel light from the target is imaged on the two-dimensional image detector 4, the infrared light emitted from the light source 5 to the left side in the figure becomes a parallel light flux by passing through the objective optical system 2. The parallel light flux enters the flat plate window 1 and most of it is transmitted, but part of it is reflected and again enters the objective optical system 2. The parallel light flux passes through the objective optical system 2 and the relay optical system 3 and is focused on the same plane as the two-dimensional image detector 4 at a position symmetrical to the optical axis of the two-dimensional detector for adjusting the relay optical system. When the objective optical system adjusting two-dimensional detector 7 is installed at this condensing point, the output becomes maximum. Next, when the environmental temperature rises in this state, the refractive index of the lens material forming the objective optical system 2 and the relay optical system 3 rises, so that the focal lengths of the objective optical system 2 and the relay optical system 3 become short. Therefore, the parallel light coming from the infinity target is imaged in front of the two-dimensional image detector 4 as shown in FIG. When the infrared light emitted to the right side of the light source 4 passes through the relay optical system optical system 3, it is condensed before the relay optical system adjusting two-dimensional detector 6, and the relay optical system adjusting two-dimensional detector 6 is collected. At the top, it spreads out and its output peaks lower. At this time, by moving the relay optical system 3 to the light source 5 side, the light can be condensed again by the relay optical system adjusting two-dimensional detector 6, and the peak of the output again becomes maximum. In this state, since the objective optical system 2 is not adjusted, the parallel light coming from the target at infinity has an image forming point on the two-dimensional image detector 4 as shown in FIG. 5C as compared with FIG. 5B. It approaches, but the image is still in front. Figure 5
In the state of (c), the infrared light emitted to the left side of the light source 5 passes through the objective optical system 2 and becomes convergent light. When a part of the converged light is reflected by the flat plate window 1 and passes through the objective optical system 2 and the relay optical system 3, it is condensed before the objective optical system adjusting two-dimensional detector 7, and the objective optical system adjusting two-dimensional detection is performed. Since it is spread on the container 7, the output peak becomes low. Here, when the objective optical system 2 is moved to the two-dimensional image detector 4 side so that the peak of the output obtained from the objective optical system adjusting two-dimensional detector 7 is maximized, the light source becomes as shown in FIG. The infrared light from 5 is focused on the two-dimensional detector 7 for adjusting the objective optical system. In this state, the parallel light from the infinity target is once imaged by the objective optical system 2 on a plane perpendicular to the optical axis 13 including the light source, and further passes through the relay optical system 3 to be formed on the two-dimensional image detector 4. The image is displayed and the focus adjustment is completed.

On the other hand, when the environmental temperature decreases, the parallel light from the infinity target is imaged by the two-dimensional image detector 4 on the right side in FIG. In order to adjust this, first, the relay optical system 3 is moved to the right side in FIG. 5 to maximize the output peak of the relay optical adjustment two-dimensional image detector 6, and the objective optical system 2 is further moved to the left side in FIG. Focus adjustment can be performed by maximizing the output peak of the two-dimensional image detector 7 for objective optical adjustment.

An embodiment of the first focus adjusting device for an infrared imaging device according to the present invention will be described below with reference to FIG. In the figure, 1 is a flat window, 2 is an objective optical system, 3 is a relay optical system, 4 is a two-dimensional image detector, 5 is a light source, 6 is a two-dimensional detector for adjusting a relay optical system, and 7 is an objective optical system adjustment. 2D detector, 8 is a processing device, 9 is a relay optical system optical axis direction moving mechanism control device, 10 is an objective optical system optical axis direction moving mechanism control device, 11 is a relay optical system optical axis direction moving mechanism,
Reference numeral 12 is an objective optical system optical axis direction moving mechanism, and 13 is an optical axis.

The focus adjusting device for an infrared imaging device according to the present invention is constructed as described above and operates as follows. The infrared light emitted from the light source 4 passes through the relay optical system 3,
The relay optical system adjusting two-dimensional detector 6 reaches the relay optical system adjusting two-dimensional detector 6, and the relay optical system adjusting two-dimensional detector 6 sends an output corresponding to the energy distribution of the reached infrared light to the processing device 8 as a signal. Further, the infrared light emitted from the light source 4 passes through the objective optical system 2, is partially reflected by the flat window 1, passes through the objective optical system 2 again,
The two-dimensional detector 7 for adjusting the objective optical system passes through the relay optical system 3 and reaches the two-dimensional detector 7 for adjusting the objective optical system. The two-dimensional detector 7 for adjusting the objective optical system outputs to the processing device 8 an output according to the energy distribution of the reached infrared light. Send as a signal. The processing device 8 obtains the amount of movement of the relay optical system 3 in the direction of the optical axis 13 and the amount of movement of the objective optical system 2 in the direction of the optical axis 13 so that the peak value of the output becomes maximum from the obtained outputs. System optical axis direction moving mechanism controller 9
Also, it issues a command to the optical axis direction movement mechanism control device 10 of the objective optical system. The relay optical system optical axis direction moving mechanism controller 9 and the objective optical system optical axis direction moving mechanism controller 10 control the relay optical system optical axis direction moving mechanism 11 and the objective optical system optical axis direction moving mechanism 12 based on this command value. , The relay optical system 3 and the objective optical system 2 are moved by a required amount in the optical axis direction. By always performing this work, it becomes possible to always image parallel light from the target at infinity on the two-dimensional image detector 4 as described in the above-mentioned principle, and focus on any change in the ambient temperature. Adjustments can be made.

Embodiment 2 An embodiment of the second focus adjusting device for an infrared imaging device according to the present invention will be described below with reference to FIG.
In the figure, 1 to 13 are parts having the same names and functions as in the first embodiment.

The focus adjusting device for an infrared imaging device according to the present invention is constructed as described above. In the first embodiment, since the flat window 1 is installed vertically with respect to the optical axis, the two-dimensional image detector 4 may detect itself and a narcissus phenomenon may occur in which the center of the screen is dark and the periphery is bright. As a countermeasure, the flat window 1 may be installed with an inclination with respect to the optical axis. FIG. 2 shows an embodiment in which the flat window 1 is tilted and installed, and operates as follows. The infrared light emitted from the light source 4 located at a distance from the optical axis 13 and transmitted through the objective optical system 2 becomes a parallel light flux inclined with respect to the optical axis 13 by an angle α ′ represented by the equation (13).

[0026]

[Equation 13]

When the flat window 1 is set so that its optical axis is incident at an angle α expressed by the equation (14), the infrared light reflected by the flat window 1 is reflected by the optical axis by an angle α expressed by the equation (15). The light flux is inclined by ″.

[0028]

[Equation 14]

[0029]

[Equation 15]

When this parallel light beam passes through the objective optical system 2 again, it is condensed on the plane perpendicular to the optical axis 13 including the light source 5 at the position of distance x'from the optical axis represented by the equation (16).

[0031]

[Equation 16]

Further, the condensed infrared light passes through the relay optical system 3 and is re-positioned on the same plane as the two-dimensional image detector 4 to a position of a distance y2 represented by the equation (17) from the optical axis 13. Collect light.

[0033]

[Equation 17]

At this position, the two-dimensional detector 7 for adjusting the objective optical system is installed. On the other hand, the infrared light passing directly from the light source 5 through the relay optical system 3 reaches the position of the distance y1 represented by the equation (18) on the same plane as the two-dimensional image detector 4.

[0035]

[Equation 18]

At this position, the two-dimensional detector 6 for adjusting the objective optical system is installed. After that, the focus adjustment can be performed by performing the same operation as that of the first embodiment.

Embodiment 3 An embodiment of the third focus adjusting device for an infrared imaging device according to the present invention will be described below with reference to FIG.
In the figure, 1 to 13 are parts having the same names and functions as those of the first embodiment, 14 is an image detection area of a two-dimensional image detector, 15 is a two-dimensional detection area for relay optical system adjustment, and 16 is an objective optical system adjustment. The two-dimensional detection area 17 is an image separation device.

The third focus adjusting device for an infrared imaging device according to the present invention is the relay optical system adjusting two-dimensional detector 6 and the objective optical system of the first focus adjusting device for an infrared imaging device according to the present invention. The adjustment two-dimensional detector 7 is replaced with a relay optical system adjustment two-dimensional detection region 15 and an objective optical system adjustment two-dimensional detection region 16 outside the image detection region 14 of the two-dimensional image detector. Two-dimensional image detector 4
Detects the target in the image detection area 14 and the image emitted from the light source 4, and outputs the image to the image separation device 17 together. The image separation device 11 uses the target two-dimensional image and the light source 4.
Image is separated and only the output obtained from the image of the light source 4 is output to the processing device 6. After that, the focus adjustment can be performed by performing the same operation as that of the first embodiment.

Embodiment 4 An embodiment of a third focus adjusting device for an infrared imaging device according to the present invention will be described below with reference to FIG.
In the figure, 1 to 17 are parts having the same names and functions as those of the third embodiment.

A fourth focus adjusting device for an infrared image pickup device according to the present invention is a relay optical system adjusting two-dimensional detector 6 and an objective optical system of a second focus adjusting device for an infrared image pickup device according to the present invention. The adjustment two-dimensional detector 7 is replaced with a relay optical system adjustment two-dimensional detection region 15 and an objective optical system adjustment two-dimensional detection region 16 outside the image detection region 14 of the two-dimensional image detector. The infrared light emitted from the light source 4 reaches the two-dimensional image detector 4 as in the second embodiment. After that, the focus adjustment can be performed by performing the same operation as that of the third embodiment.

[0041]

As described above, the first embodiment according to the present invention
According to the focus adjusting device of No. 2, the infrared light emitted from the light source is controlled to be focused on the relay optical system adjusting two-dimensional detector and the objective optical system adjusting two-dimensional detector so that the infrared light is always infinity. There is an effect that the focus of the optical system can be adjusted. However, since the flat window is installed vertically with respect to the optical axis, when the two-dimensional image detector is cooled to an extremely low temperature to improve its sensitivity, the two-dimensional image detector 4 detects itself and the center of the screen is detected. There is a possibility that a narcissus phenomenon occurs in which is dark and the surroundings are bright.

According to the focus adjusting device of the second embodiment of the present invention, the flat window is installed obliquely with respect to the optical axis, so that the optical system is always focused at infinity while avoiding the above-mentioned narcissus phenomenon. The effect is that you can.

Further, in the focus adjusting apparatus of the third embodiment according to the present invention, the two-dimensional image detector is composed of the image detecting area, the relay optical system adjusting two-dimensional area, and the objective optical system adjusting two-dimensional area.
Since the optical system is divided into areas, the optical system can be focused at infinity at all times while simplifying the configuration. However, when the number of pixels forming the two-dimensional image detector is limited, the number of pixels that can be used in the image detection area is smaller than that of the focus adjusting apparatus according to the first embodiment of the present invention, and the resolution of the obtained image is small. There is also a drawback that it becomes rough.

According to the fourth embodiment of the focus adjusting device of the present invention, the third flat plate window of the focus adjusting device of the present invention is installed obliquely with respect to the optical axis to simplify the structure, There is an effect that the optical system can always be focused at infinity while avoiding the narcissus phenomenon described above.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a focus adjustment device for an infrared imaging device according to the present invention.

FIG. 2 is a diagram showing an embodiment of a focus adjustment device for an infrared imaging device according to the present invention.

FIG. 3 is a diagram showing an embodiment of a focus adjustment device for an infrared imaging device according to the present invention.

FIG. 4 is a diagram showing an embodiment of a focus adjustment device for an infrared imaging device according to the present invention.

FIG. 5 is a diagram illustrating the principle of the present invention.

FIG. 6 is a diagram showing an embodiment of a conventional focus adjustment device for an infrared image pickup device.

[Explanation of symbols]

 1 flat plate window 2 objective optical system 3 relay optical system 4 two-dimensional image detector 5 light source 6 relay optical system adjustment two-dimensional detector 7 objective optical system adjustment two-dimensional detector 8 processor 9 relay optical system optical axis movement Mechanism control device 10 Objective optical system optical axis direction moving mechanism controller 11 Relay optical system optical axis direction moving mechanism 12 Objective optical system optical axis direction moving mechanism 13 Optical axis 14 Image detection area of two-dimensional image detector 15 Relay optical system adjustment Two-dimensional detection area 16 for objective optical system adjustment two-dimensional detection area 17 image separation device 18 memory 19 relay optical system temperature sensor 20 objective optical system temperature sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G02B 7/02 F G03B 13/36 41/00 H04N 5/232 H

Claims (4)

[Claims] 1. A flat plate window that transmits infrared rays, an objective optical system that forms an image of infrared rays that have passed through the flat plate window, a relay optical system that re-images an image formed by the objective optical system, and a relay optical system. In an infrared imager having a two-dimensional image detector installed at an image forming point, an objective optical system optical axis direction moving mechanism for moving the objective optical system in the optical axis direction and a relay optical system for moving the relay optical system in the optical axis direction. A relay optical system optical axis direction moving mechanism is provided, and the flat plate window is installed perpendicularly to the optical axis and on the same plane as the two-dimensional image detector outside the image detection area of the two-dimensional image detector. Two-dimensional detector for adjusting relay optical system,
A two-dimensional detector for adjusting the relay optical system is provided on the same plane as the two-dimensional image detector, and a two-dimensional detector for adjusting the objective optical system is provided at a position symmetrical with respect to the optical axis. A light source is provided in an optically conjugate position through the dimension detector and the relay optical system, and the optical axis direction of the relay optical system is set so that the peak value of the output of the relay optical system adjusting two-dimensional detector is maximized. A processing device for obtaining and outputting the movement amount and for obtaining and outputting the movement amount of the objective optical system in the optical axis direction so that the peak value of the output of the two-dimensional detector for adjusting the objective optical system is maximized, and a given optical axis Device for controlling the optical axis direction movement mechanism of the relay optical system so that the movement amount of the optical axis direction becomes the amount of direction movement, and the optical axis direction movement of the objective optical system so that the given movement amount of the optical axis direction becomes Mechanism controlling pair Focusing apparatus of an infrared imager, characterized in that an optical system the optical axis direction moving mechanism control apparatus. 2. A flat plate window that transmits infrared rays, an objective optical system that forms an image of infrared rays that have passed through the flat plate window, a relay optical system that re-images an image formed by the objective optical system, and a relay optical system. In an infrared imager having a two-dimensional image detector installed at an image forming point, an objective optical system optical axis direction moving mechanism for moving the objective optical system in the optical axis direction and a relay optical system for moving the relay optical system in the optical axis direction. A relay optical system optical axis moving mechanism is provided so that the vertical axis of the flat window is at an angle α with respect to the optical axis, and the two-dimensional image detector is on the same plane as the two-dimensional image detector.
A two-dimensional detector for adjusting a relay optical system installed at a position of a distance y1 from the optical axis outside the image detecting area of the three-dimensional image detector, and a two-dimensional detecting for adjusting the relay optical system on the same plane as the two-dimensional image detector A two-dimensional detector for adjusting an objective optical system installed at a position of a distance y2 in the same direction with respect to the optical axis and the optical axis, and a light which is an optically conjugate position through the two-dimensional detector for adjusting a relay optical system and the relay optical system. A light source is provided at a position at a distance x from the axis, and the movement amount in the optical axis direction of the relay optical system is calculated and output so that the peak value of the output of the relay optical system adjustment two-dimensional detector is maximized and the objective optical system is also provided. A processing device for obtaining and outputting the amount of movement of the objective optical system in the optical axis direction so that the peak value of the output of the adjustment two-dimensional detector is maximized, and the relay optical system so that the given amount of movement of the optical axis direction is obtained. Controls optical axis movement mechanism A relay optical system optical axis direction moving mechanism control device and an objective optical system optical axis direction moving mechanism control device for controlling the objective optical system optical axis direction moving mechanism so as to obtain a given optical axis direction moving amount. , X, y1, y2
A focus adjusting device for an infrared imaging device, characterized in that there is a relationship of (1), (2), and (3) between. [Equation 1] [Equation 2] [Equation 3] 3. A flat plate window for transmitting infrared rays, an objective optical system for forming an image of infrared rays transmitted through the flat plate window, a relay optical system for re-forming an image formed by the objective optical system, and a relay optical system. In an infrared imager having a two-dimensional image detector installed at an image forming point, an objective optical system optical axis direction moving mechanism for moving the objective optical system in the optical axis direction and a relay optical system for moving the relay optical system in the optical axis direction. A relay optical system optical axis direction moving mechanism is provided, the flat plate window is installed perpendicularly to the optical axis, and a relay optical system adjustment two-dimensional detection area is set outside the image detection area of the two-dimensional image detector. And an objective optical system adjusting two-dimensional detecting region installed at a position symmetrical with respect to the optical axis outside the image detecting region of the two-dimensional image detector, and the relay optical system adjusting two-dimensional detecting region and the relay optical system. Through optical A light source is provided at a position conjugate, said relay optical system adjusting 2
The optical axis direction movement amount of the relay optical system is calculated and output so that the peak value of the output of the dimension detection region is maximized, and the objective is adjusted so that the peak value of the output of the two-dimensional detection region for adjusting the objective optical system is maximized. A processing device for obtaining and outputting a movement amount in the optical axis direction of the optical system, and a relay optical system optical axis direction moving mechanism control device for controlling the relay optical system optical axis direction moving mechanism so that the given movement amount is obtained. And an objective optical system optical axis direction moving mechanism control device for controlling the objective optical system optical axis direction moving mechanism so as to obtain a given optical axis direction moving amount. 4. A flat plate window which transmits infrared rays, an objective optical system which forms an image of infrared rays which have passed through the flat plate window, a relay optical system which re-images an image formed by the objective optical system, and a relay optical system. In an infrared imager having a two-dimensional image detector installed at an image forming point, an objective optical system optical axis direction moving mechanism for moving the objective optical system in the optical axis direction and a relay optical system for moving the relay optical system in the optical axis direction. A relay optical system optical axis moving mechanism is provided, the flat window is installed so as to be incident at an angle α with respect to the optical axis, and a distance y1 from the optical axis is outside the image detection area of the two-dimensional image detector. 2 for adjusting relay optical system set to position
A two-dimensional detection area for adjusting the objective optical system, which is installed outside the two-dimensional image detector image detecting area and at a distance y2 in the same direction as the relay optical system adjusting two-dimensional detecting area with respect to the optical axis. And a light source is provided at a point at a distance x from the optical axis located at a conjugate position through the relay optical system adjustment two-dimensional detection region and the relay optical system, and the output of the relay optical system adjustment two-dimensional detector is peaked. The amount of movement of the relay optical system in the optical axis direction is calculated and output so as to maximize the value, and the objective optical system is moved in the optical axis direction so that the peak value of the output of the two-dimensional detector for adjusting the objective optical system becomes maximum. A processing device for obtaining and outputting the amount, a relay optical system optical axis direction moving mechanism control device for controlling the relay optical system optical axis direction moving mechanism so as to obtain a given optical axis direction moving amount, and a given optical axis direction To be the amount of movement The result from the objective optical system in the optical axis direction moving mechanism control apparatus for controlling the objective optical system in the optical axis direction moving mechanism, alpha, between the x, y1, y2 (4), (5), (6)
A focus adjusting device for an infrared imaging device, characterized in that there is a relation of formula. [Equation 4] [Equation 5] [Equation 6]