JPH05172635A - Infrared video apparatus - Google Patents

Abstract

PURPOSE:To contrive a longer life of a detector by a method wherein the level of input infrared rays to be detected with the detector to control a variable opening stop according to the level and a proper quantity of light received is applied to the detector to eliminate operating disturbance. CONSTITUTION:A detector 3 converts infrared rays incident via a lens 1 and a variable opening stop part 11 into an analog signal to be applied to a signal processing section 21. The signal processing section 21 converts the signal into a digital image signal to be sent to a display/image processing section 22 and an infrared image of a target object is shown on a display device. The digital image signal is also sent to a detecting section 23, with which a p-p(peak-peak) value of the signal per frame of the digital image is detected. The p-p value is smoothed with a smoothing processing section 24 to output the maximum value of the image signal per frame and the maximum value is compared with a reference value by a difference computing section 25 to obtain a difference value. The difference value is converted into an analog signal with an A/D converter 26 to be amplified in power with a power amplifier 27 and the results are applied to the stop part 11 to control a specified opening area.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an infrared imager,
In particular, it relates to an optical system of an infrared imager.

In an infrared imaging device comprising a housing containing a lens for receiving infrared light and a detector connected to the housing for detecting infrared light, the housing emits infrared light depending on the housing temperature. Therefore, when the emitted infrared rays enter the detector, the output of the detector fluctuates due to the fluctuation of the housing temperature, and the image quality of the infrared imaging device deteriorates. Therefore, there is a need for an optical system that can prevent infrared rays emitted from the housing from entering the detector.

[0003]

2. Description of the Related Art FIG. 8 is a Japanese Patent Laid-Open No. 1-155220 filed by the applicant of the present invention, which comprises a housing and a detector as described above.
1 is a view showing a conventional infrared imager disclosed in Japanese Patent Laid-Open Publication No. 2004-242242, in which an optical element such as a lens 1 is attached to a housing 2;
It is fixed to one end face of the housing 2, and the detector 6 is attached to the other end face of the housing 2.

A window 7 is provided on the input side of the detector 6, a cold shield 5 is provided inside the detector 6, and a detecting element 3 is provided inside the cold shield 5. ..

In such a state, infrared light a (shown by a solid line) from the target object is converged by the lens 1, passes through the window 7 and enters the detector 6, and further passes through the light passage hole 8 of the cold shield 5. The light is incident on the light detecting element 3 to be detected.

With such a structure alone, infrared rays a depending on the housing temperature are radiated from the inner wall of the housing 2, and when the radiated infrared rays a enter the sensing element 3, the output of the sensing element 3 varies due to the variation of the housing temperature. As a result, the image quality of the infrared imaging device deteriorates.

Therefore, in order to block the infrared rays a from the housing 2, the window 7 side is formed of a concave light reflecting layer 9 and the lens 1 side is formed of a light absorbing layer 10 at a predetermined position of the housing 2, and Lens 1 on the central optical axis
The aperture stop 11 is provided to pass only the converged infrared light.

By doing so, most of the infrared light a radiated from the inner surface of the housing 2 between the lens 1 and the aperture stop 11 is mostly the light absorption layer 10 of the aperture stop 11.
Is absorbed by the aperture stop 11 and cold shield 5
Infrared light b emitted from the components existing between and is reflected by the light reflection layer 9 formed on the concave surface of the aperture stop 11 at an angle at which it does not enter the sensing element 3 and enters the cold shield 5. Is preventing.

The infrared light c emitted from the inner surface of the housing between the light reflecting layer 9 and the window 7 is prevented from entering the detecting element 3 due to the blocking effect of the light passage hole 8 of the cold shield 5.

[0010]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
In the infrared imager disclosed in Japanese Patent No. 155220, the amount of infrared radiation emitted from the inner surface of the housing to the detection element 3 is reduced. However, since the aperture of the aperture diaphragm 11 is constant, for example, strong infrared light is emitted. There is a problem that the amount of light received by the detection element 3 becomes excessive when input, and normal operation cannot be performed as an infrared imaging device.

Therefore, according to the present invention, a housing having a lens on one end surface for receiving infrared light and a cold shield having the infrared light provided therein via a window joined to the other end surface of the housing are further provided inside. It is an object of the present invention to provide an infrared imaging device configured with a detector that receives light by a detection element, so that the diaphragm of the aperture diaphragm can be changed according to the level of input infrared light.

[0012]

In order to achieve the above object, an infrared imaging device according to the present invention, as shown schematically in FIG. 1, has a predetermined space in a housing between a lens 1 and a detector 6. At the position, the side of the detector 6 is formed by the light reflecting layer 9 having a concave surface, the side of the lens 1 is formed by the light absorbing layer 10, and the variable aperture diaphragm portion which passes only the converged infrared light of the lens 1 on the central optical axis. 11 and a control unit 20 that controls the diaphragm of the variable aperture diaphragm unit 11 according to the input infrared level detected by the detection element 3.

The variable aperture diaphragm 11 is composed of a plurality of movable blades, a motor provided on the outer periphery of the housing 2 and having a rotating ring that moves parallel to the central optical axis of the housing 2, and the housing 2 A slider provided on the outer periphery of the slider and moving in parallel with the central optical axis by the rotational movement of the rotary ring, and a holding pin attached to the slider for opening and closing the movable blade.

Further, the control section 20 can convert the input infrared light into a digital image signal, detect the maximum level of the image signal for each frame, and control the motor according to the average level.

[0015]

In the operation of the infrared imaging apparatus according to the present invention, the control unit 20 detects the level of the input infrared light detected by the detecting element 3 as shown in FIG. 1, and the control unit 20 responds to the level. The aperture of the variable aperture diaphragm unit 11 is controlled by the control.

As a result, when the input level of infrared light is high, the aperture of the variable aperture stop 11 is made small, and when the input level of infrared light is low, the variable aperture stop 11 is loosened so that the detection element 3 always receives light. The amount is kept at an appropriate value to keep the infrared imager operating normally.

[0017]

FIG. 2 shows a schematic structure of the variable aperture diaphragm portion 11 shown in FIG. 1. First, the housing 2 is provided with a ring-shaped motor 12 on its outer periphery. A slider 123 driven by the motor 12 is provided between the housing 2 and the housing 2.

Further, the housing 2 is provided with an elongated hole 13 as a groove, and a holding pin 124 is attached to the slider 123 in the elongated hole 13 so as to be movable in the elongated hole 13 together with the slider 123. ing. A spring 125 is built in the holding pin 124 as shown in the drawing, and it is always moving toward the central axis of the housing 2.
6, the presser pin 124 is contacted at this contact point.
Is supposed to stop. In other words, the blade 126 reaches the position determined by the pressing pin 124.
Rotates about the blade shaft 127 and stops.

The slider 123 is designed to move upwards in the drawing against the spring 129 while rotating around the axis of the housing 2 when a predetermined signal is applied to the motor 12, and the upper presser 130 is used. The upper limit is set. Further, the slider 123 is moved downward by the motor 1
This is performed by the repulsive force of the spring 129 due to the reverse rotation of 2. Incidentally, 14 is a fixing portion for fixing the motor 12.

Along with this, the slider 123 moves the pressing pin 124 to stop the blade 126 at a predetermined position, so that an opening 128 as shown is formed and infrared light can be received from this opening 128. ing.

Although only two holding pins 124 are shown in the illustrated state, two more holding pins 124 are also provided in the direction perpendicular to the plane of the drawing, and the blade shaft 127 is similarly provided.
There are four in total.

FIG. 3 shows the case where the opening 128 obtained by driving the blade 126 in the structure as shown in FIG. 2 is the smallest, and in this embodiment, four blades 126 are provided.
a to 126d are provided and blades 126a and 1
26b moves up and down in the figure, and blades 126c and 12
The opening 128 is formed by moving 6d in the left-right direction in the drawing. Incidentally, FIGS. 11B and 11C are diagrams when the state of FIG. 11A is viewed from the left and right and from above and below, respectively.

FIG. 4 similarly illustrates blades 126a-12.
It shows the largest opening 128 formed when driving 6d.

FIG. 5 is a perspective view of the variable aperture diaphragm 11 shown in FIG. 2. In this embodiment, the motor 12 is used.
Is an outer cylinder 120 as a stator provided on the outermost side of the housing 2, and a rotor 121 provided inside the outer cylinder 120.
And a key 1210 provided inside the rotor 121.
And a rotating ring 122 that rotates together with the rotor 121.

Further, the rotary ring 122 and the slider 123
Are threadedly engaged by the thread crests 123a and the troughs 123b. Therefore, when the rotor 121 rotates, the rotary ring 122 also rotates, which causes the slider 123 to move up and down while rotating. There is.

Further, as can be seen from this figure, the housing 2 is formed with an elongated hole (groove) 13, and the elongated hole 13 is formed.
A pressing pin 124 provided on the slider 123 is configured to move along. As described above, when the slider 123 translates upward in the drawing, for example, the rotary ring 122
However, when the rotating ring 122 rotates in the direction opposite to that shown in the drawing, it is pushed downward by the spring 129.

Then, the slider 1 is attached by the rotating ring 122.
An upper presser foot 130 is provided to prevent the presser pin 124 from moving beyond the maximum position when the presser pin 23 is moved.

FIG. 6 is a plan sectional view of the variable aperture diaphragm 11 taken along the line XX in FIG. 5. As can be seen from this figure, the holding pin 124 has a slider 123 longer than the other. It is designed to fit in the hole 13,
From this fitted state, the pressing pin 124 is moved to the blade 12
A spring 131 is provided inside so as to push 6.

In this way, the slider 123 is formed into the elongated hole 13.
The presser pin 124 moves along with the blade 12 as it slides.
6 is opened or closed to control the area of the opening 128.

FIG. 7 shows an embodiment of the control section 20 for controlling the variable aperture stop section 11 shown above. The lens 1 shown by a dotted line, the variable aperture stop section 11, and the detecting element 3 are shown in FIG. Is the same as shown above.

In the detection element 3, when the infrared light incident through the lens 1 and the variable aperture stop 11 is converted into an analog signal and given to the signal processor 21, the signal processor 2
In No. 1, the input analog signal is converted into a digital image signal and sent to the display / image processing unit 22 to display an infrared image of the target object on a display (not shown).

Further, the digital image signal of the signal processing unit 21 is also sent to the detection unit 23, where the value of pp (peak-peak) in the signal for each frame of the digital image is detected. The pp value detected by the detection unit 23 is smoothed by the smoothing processing unit 24 and the maximum value of the image signal for each frame is output, and this maximum value and the reference value are compared in the difference calculation unit 25. By doing so, the difference value between the two can be obtained.

The difference value obtained by the difference calculator 25 is D / A.
The variable aperture stop unit 1 is converted into an analog signal by the converter 26 and then power-amplified by the power amplifier 27.
Will be given to 1.

Therefore, the amount of movement of the rotary ring 122 of the motor 121 of the variable aperture stop unit 11 is determined depending on how much the maximum level of the currently detected infrared light differs from the reference value, and accordingly. Slider 12
The holding pin 124 controls the blade 126 to have a predetermined opening area via the pin 3.

[0035]

As described above, according to the infrared imaging device of the present invention, the aperture of the aperture stop is controlled in accordance with the input infrared level detected by the detecting element. If the aperture becomes too large or too small, an appropriate amount of received light will be given to the detection element by the corresponding aperture stop.
It is possible to eliminate the operation trouble of the infrared imaging device and extend the life of the detection element.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an infrared imaging device according to the present invention.

FIG. 2 is a schematic configuration diagram of a variable aperture stop unit used in the infrared imaging device according to the present invention.

FIG. 3 is a diagram showing a state in which a minimum opening is obtained by controlling a blade used in the present invention.

FIG. 4 is a view showing a state in which a maximum opening is obtained by controlling a blade used in the present invention.

FIG. 5 is a perspective view showing an embodiment of a variable aperture stop unit used in the present invention.

6 is a plan sectional view of the variable aperture stop section taken along the line XX in FIG.

FIG. 7 is a block diagram showing a configuration of an embodiment of a control unit used in the infrared imaging device according to the present invention.

FIG. 8 is a diagram showing a conventional technique (Japanese Patent Laid-Open No. 1-155220).

[Explanation of symbols]

 1 Lens 2 Housing 3 Detecting Element 5 Cold Shield 6 Detector 7 Window 9 Light Reflecting Layer 10 Light Absorbing Layer 11 Variable Aperture Stopper 12 Motor 13 Elongated Hole 20 Controller 123 Slider 124 Presser Pin 125 Spring 126 Blade 128 Opening The same reference numerals indicate the same or corresponding parts

Claims (3)

[Claims] 1. A lens (1) on one end face for receiving infrared light
And a sensing element (3) further provided inside the cold shield (5) having the infrared light provided therein through a window (7) joined to the other end surface of the housing (2). ) In the infrared imaging device comprising a detector (6) for receiving light, a concave surface on the detector (6) side is provided at a predetermined position in the housing between the lens (1) and the detector (6). Light Reflection Layer (9)
A variable aperture stop portion (11) that passes only the converged infrared light of the lens (1) on the central optical axis, and the light absorption layer (10) is formed on the side of the lens (1). An infrared imaging device comprising: a control unit (20) for controlling the diaphragm of the variable aperture diaphragm unit (11) according to an input infrared level detected by a detection element (3). 2. The variable aperture stop section (11) is provided on a plurality of movable blades and a rotating ring which is provided on the outer periphery of the housing (2) and moves parallel to the central optical axis of the housing (2). A motor having a motor, a slider that is provided on the outer periphery of the housing (2) and moves in parallel with the central optical axis by the rotational movement of the rotating ring, and a holding pin that is attached to the slider and that opens and closes the movable blade. The infrared imaging device according to claim 1, wherein the infrared imaging device comprises: 3. The control unit (20) converts the input infrared light into a digital image signal, detects the maximum level of the image signal for each frame, and controls the motor according to the average level. The infrared imaging device according to claim 2.