JP3174891B2 - Infrared camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared camera used for an infrared thermal imaging device.

[0002]

2. Description of the Related Art Generally, an infrared camera used in an infrared thermal imaging apparatus for detecting infrared radiation emitted from the surface of a subject and displaying a temperature distribution as a visible image (thermal image) is shown in FIG. Some are configured as follows. First, the optical system scanning mechanism of the infrared camera will be described. Light emitted from the surface of the subject 50 is blocked by a silicon window 51 provided in a front opening (not shown) of a housing (not shown) so that visible light 52 is blocked. Incident. In the housing, a decahedral rotating mirror 55 rotated at a constant speed by a driving motor (not shown) is disposed on substantially the same plane as the silicon window 51, and is incident on the housing. The infrared light 53 enters the rotating mirror 55.

The rotating mirror 55 has a polygonal pyramid shape in which mirrors 55a to 55j each having a decahedral shape are slightly inclined in a direction perpendicular to the rotation center O of the rotating mirror. Therefore, when the infrared ray 53 enters the rotating mirror 55, it is reflected by each of the mirrors 55a to 55j. At this time, each of the mirrors 55a to 55j scans a portion of the subject 50 that is slightly shifted in the vertical direction in the horizontal direction, and scans a range of 1 ° in the vertical direction with one rotation of the rotating mirror 55. You. The infrared light 53 scanned in the horizontal and vertical directions in this manner is reflected by a turn-back mirror 56 disposed substantially on the same plane as the rotating mirror 55, passes through an infrared transmission filter 57, and is condensed. 58
The beam is converged by this to be incident on the infrared detector 59.

The infrared detector 59 is composed of ten detection elements arranged in parallel in the direction of the rotation center O of the rotation mirror 55, and the element interval is 1 for each element for a vertical viewing angle of 10 °. The interval is set to an angle corresponding to every °.
Therefore, in the first mirror 55a of the rotary mirror 55, the infrared detector 59 of 10 elements simultaneously receives thermal image signals at intervals of 1 ° with respect to the vertical direction of the subject 50, and the thermal image signal is 0.1% per line.
It is output as ten scanning line signals with an interval of °. Next, with the rotation of the rotating mirror 55, the next mirror 55 is rotated.
b reflects the infrared light 53 from the subject 50,
Due to the difference in inclination of 55b, a 10-element infrared detector 59
Receive the thermal image signals at positions shifted by 0.1 ° from the previous position at the same time, and similarly output as ten scanning line signals at intervals of 0.1 ° per line.

[0005] When the rotating mirror 55 makes one rotation in this way, the object 50 has been scanned over a vertical viewing angle of 10 °, and ten 0.
Infrared rays 53 from different subjects 50 enter by 1 ° each, and the infrared detector 59 as a whole is output as 100 infrared scanning signals. The infrared scanning signal output from the infrared detector 59 is amplified by an amplifier circuit 60, processed by a processor 61, and displayed as a thermal image on a monitor 62.

On the other hand, since the infrared detector 59 detects the infrared ray 53 and converts it into an electric signal, the thermal image of the subject 50 whose temperature is changing can be reduced to two by a limited number of elements.
In order to form a two-dimensional image and obtain high sensitivity, an infrared detector 59 having high sensitivity and high response speed is required. Therefore, conventionally, a quantum infrared detector 59 such as indium antimony (InSb) or mercury cadmium tellurium (HgCdTe) has been used. However, these In
Since the Sb element and the HgCdTe element need to be cooled at an extremely low temperature of about -200 ° C in order to obtain the highest sensitivity, a JT cooler method using an argon gas as a cooling medium, a liquid nitrogen cooling method, etc. It has been cooled to cryogenic temperatures.

[0007]

As described above, in contrast to the structure in which the infrared ray 53 is optically scanned in the horizontal and vertical directions by one rotating mirror 55, the scanned infrared ray 53 is condensed by the condenser lens 58. Detector 5 to focus light
9 has a plurality of elements and is 1 ° with respect to the vertical direction.
Are arranged at intervals corresponding to the above, and the light-condensing positions are wide in a plurality, resulting in positional displacement, that is, scanning distortion. In the design, the subject 50
When the distance between the camera and the infrared camera is at a certain distance,
Although the design is made so as to eliminate this scanning distortion, there is a problem that the scanning distortion increases when the distance deviates much more than that. In addition, one folded mirror-5
It is time-consuming and very difficult to correct the deviation of the optical axis of the infrared ray 53 in the vertical direction and the horizontal direction in Step 6, and
This adjustment requires skill and takes a lot of time.

[0008]

[MEANS FOR SOLVING THE PROBLEMS] The present invention provides a window that transmits only infrared rays emitted from the surface of a subject,
The reflecting surface is provided to be inclined in the vertical direction, receives the infrared light transmitted through the window, and supports a first folded mirror that reflects in the vertical direction, and supports the first folded mirror. A first support column for setting a tilt angle in the direction, a vertical adjustment mechanism provided on the back of the first folding mirror for finely adjusting the vertical tilt angle, and an infrared ray from the first folding mirror. A vibration mirror that receives light and scans it at a predetermined angle in the vertical direction, a rotating mirror that receives infrared light scanned vertically by the vibration mirror and scans it in the horizontal direction, and a reflecting surface that is inclined in the horizontal direction A second folding mirror which receives the horizontally and vertically scanned infrared rays from the rotating mirror and reflects the infrared rays in the horizontal direction; and supports the second folding mirror and also supports the second folding mirror in the horizontal direction of the reflection surface. Angle of inclination A second support column for setting the turning mirror, and a horizontal adjusting mechanism provided on the back of the second turning mirror for finely adjusting the inclination angle of the turning mirror in the horizontal direction. By providing an infrared detector that receives infrared rays and outputs it as a thermal image signal, a thermal image with high sensitivity in real time without spatial displacement and scanning distortion can be obtained.

[0009]

The infrared rays emitted from the subject and passed through the window are received by the first turning mirror and reflected in the direction of the vibration mirror. At this time, the optical path deviation of the infrared light beam in the vertical direction is finely adjusted in the vertical direction of the reflection surface by the vertical adjustment mechanism. The infrared light received by the vibration mirror is scanned at a predetermined angle in the vertical direction and is reflected in the direction of the rotating mirror.
The infrared light incident on the rotating mirror is scanned in the horizontal direction by each plane mirror. The infrared rays scanned in the horizontal and vertical directions are received by the second folding mirror. Here, the horizontal adjustment mechanism makes fine adjustment in the horizontal direction with respect to the optical path of the infrared light flux on the reflection surface, enters the infrared detector, performs photoelectric conversion by the infrared detector, and outputs a thermal image signal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2 are a plan view and a vertical sectional view, respectively, of an optical system scanning mechanism of an infrared camera.
FIG. 4 is a perspective view of an essential part showing an optical system scanning mechanism of an electronically cooled infrared camera, FIG. 4 is a sectional view of an essential part of a horizontal and vertical adjustment mechanism, and FIG. It is. 1 to 3, reference numeral 1 denotes a subject, 2
Is a window that transmits visible light, 3 is an infrared ray (infrared image) emitted from the subject 1, and 4 is a window that blocks the visible light 2 and transmits only the infrared ray 3, and is made of silicon.
Window fixing member 1 in an opening 12 opening in front of
3 fixed.

Reference numeral 5 denotes a first folding mirror, which receives infrared rays 3 of the subject 1 transmitted through a window (hereinafter, referred to as a silicon window) 4 and reflects the infrared rays 3 to a vibration mirror 6 located vertically below. The mirror that covers the rotating mirror 7
It is fixed to the upper surface of the cover part 14 by screws 16 via support columns 15, and is disposed so as to be located on substantially the same plane as the silicon window 4. The vertical tilt angle of the first turning mirror 5 is set by the support pillar 15, and the reflecting surface 5a is accurately set to the vibration mirror 6
A vertical adjustment mechanism 17 for finely adjusting the inclination angle of the reflection surface 5a is provided on the back surface of the first folded mirror 5 so as to face in the direction.

The vertical adjustment mechanism 17 includes a fixing screw 18 and three adjusting screws 19, 20, 2 provided at the respective vertices of a substantially equilateral triangle with the fixing screw 18 as a center.
0 '. The fixing screw 18 is for fixing the turning mirror 5 to the support column 15, and the adjusting screws 19, 20, and 20 'are for finely adjusting mainly the inclination angle of the turning mirror 5 in the vertical direction. As shown in FIG. 4, the support column 15 has a hole 15a through which the fixing screw 18 penetrates and screw holes 15b, 15c, 15d through which adjustment screws 19, 20, 20 'penetrate. An aluminum plate 17a is provided between the support pillar 15 and the first folded mirror 5, and this aluminum plate 17
a, the hole 15a of the support column 15 and the screw holes 15b, 15
Screw holes 17b for fixing screws 18 facing c and 15d
And adjustment screws 19, 20, 2
Concave grooves 17c, 17d, and 17e into which the tip of 0 'fits are formed, and by adjusting screws 19, 20, and 20', the tilt angle of the folded mirror 5 in the vertical direction is finely adjusted. It is configured to be able to.

Reference numeral 6 denotes a vibration mirror for scanning the reflected light (infrared light) 3 from the return mirror 5 in the vertical direction, and a rotating mirror.
7 is located substantially on the same plane as the silicon window 4 when viewed from the vertical direction.
, A predetermined angle (a vertical viewing angle) is vibrated in the vertical direction, and in this embodiment, it is set so as to vibrate in an effective range of 10 ° in the vertical direction. The rotating mirror 7 is formed in an annular shape by eight plane mirrors 7a to 7h, and each of the plane mirrors 7a... Is attached to the rotating shaft of the motor 22 so that all the plane mirrors 7a. Have been. The surroundings of the rotating mirror 7 are plane mirrors 7a and 7b.
, A mirror provided on the upper surface of the motor case 23 in order to prevent dust from adhering to the rotating mirror 7 and to prevent noise caused by rotation of the rotating mirror 7.
It is covered with a cover part 14. The rotating mirror 7 is rotated at a high speed by the motor 22 at a constant speed. In this embodiment, the rotating speed is set to 14,400 rpm.

Reference numeral 8 denotes a second turning mirror, which is a rotating mirror.
7 receives the infrared rays 3 scanned in the horizontal direction by the plane mirrors 7a.
Reflected in the zero direction, it is positioned on substantially the same vertical plane as the silicon window 4 and on the same plane as the rotating mirror 7 and is fixed to the housing 11 via the support column 24 by screws 25. . First folding mirror
5, the horizontal tilt angle of the turning mirror 8 is set by the support column 24, and a horizontal fine adjusting mechanism 26 for finely adjusting the tilt angle is provided by the second turning mirror.
8 on the back. The horizontal adjusting mechanism 26 includes a fixing screw 27 and an adjusting screw 2 provided at each vertex of a substantially equilateral triangle with the fixing screw 27 as a center.
8, 29, and 29 ', which have the same configuration and operation as the vertical adjustment mechanism 17, so that detailed description is omitted. Reference numeral 9 denotes a condenser lens, which detects reflected light (infrared light) 3 from the second turning mirror 8 by an infrared detector 1
A lens for forming an image at 0, which is fixed to the housing 11 via a support column 31 by a screw 30.

The infrared detector 10 is an electronically cooled single element sprite element (Singnal Procesing In The Elemen).
t) is used, and as shown in FIG.
6 is connected to an amplifier 37 to perform photoelectric conversion. The infrared detector (sprite element) 10 is of an electronic cooling type and is cooled to about -70 ° C. The infrared detector 10 is vertically separated from the silicon window 4 so that the vibration mirror 6, the rotation mirror 7 and the second folded mirror are provided.
8 and is arranged as close as possible to the vertical plane where the silicon window 4 is located. Reference numeral 34 denotes a processor which is arranged outside the infrared camera and performs various signal processing. 35 is the subject 1
A display device 38 for displaying the thermal image of the above is a bias electrode of the sprite element 32.

Next, the operation will be described. First,
In the optical scanning mechanism, the infrared rays 3 from the subject 1
However, in order to completely separate the part that spatially transmits the line scanning in the horizontal direction from the infrared detector 10 and the part that spatially transmits the line scanning in the vertical direction,
In order to use the rotating mirror 7 and the vibration mirror 6 and to make the vertical optical axis fine adjustment and the horizontal optical axis fine adjustment independent, a vertical mirror 5 and a horizontal mirror 8 are used. Is used. The turning mirror 5 must be positioned so as to receive the infrared rays 3 incident from the silicon window 4 and to totally reflect the infrared rays 3 to the vibrating mirror 6. The turning mirror 8 is a rotating mirror 7
Must be positioned so as to receive the scanned infrared image 3 from the lens and reflect it completely to the condenser lens 9 accurately. However, both of them are machined, and the parts such as the support columns 15 and 24 that support them are also machined. Therefore, a slight shift occurs in the vertical and horizontal directions in design.

In an optical system, it is very important to correct this shift. Therefore, the vertical displacement is corrected mainly by the vertical adjustment mechanism 17 provided on the back surface of the first turning mirror 5. That is, since the mirror portion of the folded mirror 5 has a free end around the fixing screw 18, the adjustment is necessary when the reflecting surface 5a of the folded mirror 5 is changed upward. Screws 19 and 20 and adjusting screw 20 ′
Is pulled out in the opposite direction, the reflecting surface 5a is inclined vertically upward about the fixing screw 18. On the other hand, when tilting downward, fine adjustment in the vertical direction is performed in the reverse procedure. The horizontal adjustment mechanism 26 provided on the back surface of the second folding mirror 8 is used for horizontal displacement.
Will be corrected by That is, similar to the vertical adjustment mechanism 17,
The mirror portion of the folded mirror 8 has a free end at the circumferential end centering on the fixing screw 27, so that the horizontal inclination angle of the reflection surface 8a is finely adjusted in the same manner as described above.

Next, the infrared detector 10 is separated from the silicon window 4 in the vertical direction, and is arranged as close as possible to the vertical plane where the silicon window 4 is located. This is conventionally known as an infrared detector 5
9 is located on substantially the same plane as the silicon window 51, the optical path length of the scanning system becomes longer, and the infrared detector 59 is located rearward when viewed from the silicon window 51. Depending on the direction, infrared rays directly enter the infrared detector 59 from the silicon window 51 without passing through the optical system scanning mechanism, and an accurate thermal image could not be obtained. In addition, since the length of the optical system becomes longer, if the portion of this optical system is housed in the housing 11, the length of the infrared camera 54 itself in the horizontal direction becomes longer, and the size of the infrared camera 54 cannot be reduced. As described above, in this embodiment, the infrared detector 10 is vertically separated from the silicon window 4 and is arranged as close as possible to the vertical plane where the silicon window 4 is located. Infrared (rotating mirror) passing through the system
(Only infrared light 3 reflected at 7) Since infrared light other than 3 does not directly enter, an accurate thermal image can be obtained.

Next, the optical scanning mechanism will be described with reference to FIG. Light from the surface of the subject 1 is blocked from visible light 2 by the silicon window 4 provided in the opening 12 of the housing 11, and only the infrared light 3 enters the infrared camera. The infrared light (infrared image) 3 incident on the inside is reflected by the first turning mirror 5 located on the same plane as the silicon window 4 in the direction of the vibration mirror 6 located almost on the same plane as the rotating mirror 7. Is done.
This reflected light (infrared light 3) is vertically shaken by about 10 ° by the vibration mirror 6, and the plane mirrors 7a,.
・ It is incident on Therefore, each of the plane mirrors 7a... Scans a portion of the surface of the subject 1 that is slightly displaced in the vertical direction in the horizontal direction by vibrating the vibration mirror 6 in the vertical direction. Usually, the number of horizontal scanning lines of this type of device is 10
It is about 0. In this embodiment, an octahedral rotating mirror is used.
Since the rotation mirror 7 is used, the rotation mirror 7 must rotate at least 12.5 times while the vibration mirror 6 swings by 10 °. It is spinning. That is, a range of 10 ° in the vertical direction is scanned by 16 rotations of the rotating mirror 7, reflected in the direction of the second turning mirror 8, reflected in the direction of the condenser lens 9, and reflected by the condenser lens 9. The luminous flux is focused and incident on the infrared detector 10, and is optically scanned on the surface of the infrared detector 10 in the direction shown by the arrow B, whereby the infrared detector 10
Is transmitted in the scanning direction indicated by the arrow B, and the electric signal of the thermal image is amplified by the amplifier 33, subjected to various kinds of signal processing by the processor 34, and displayed on the display device 35.

On the other hand, the infrared light 3 corresponding to 0.1 ° is incident on the infrared detector 10 by the one plane mirror 7a.
When the next plane mirror 7b scans, the vibration mirror
6 is shifted by 0.1 ° in the vertical direction.
The position which is shifted by 0.1 ° in the vertical direction from the part horizontally scanned in a is also scanned. Accordingly, one rotation of the rotating mirror 7 scans the subject 1 in the vertical direction at 10 °, and the horizontal direction is 15 ° in the horizontal direction by the plane mirrors 7a of the rotating mirror 7 in the horizontal direction. Is scanned. Therefore, in order to obtain a thermal image with 100 horizontal scans in real time, the rotational speed of the rotating mirror 7 is set to 14400 rpm.
The image is set to rotate at a high speed, and a real-time thermal image signal of 15 screens is obtained from the infrared detector 10 per second.

[0021]

According to the present invention, there is provided a window which transmits only infrared rays radiated from the surface of a subject and a reflecting surface which is provided to be inclined in a vertical direction, receives the infrared rays transmitted through the window, and reflects the infrared rays in the vertical direction. A first folding mirror, a first support column for supporting the first folding mirror and setting a vertical inclination angle of the reflection surface, and provided on a back surface of the first folding mirror; A vertical adjustment mechanism for finely adjusting the tilt angle in the vertical direction, and a vibration mirror for receiving infrared rays from the first turn-back mirror and scanning vertically at a predetermined angle.
A rotating mirror for receiving infrared light scanned in the vertical direction by the vibration mirror and scanning the infrared light in the horizontal direction, and a reflecting surface provided to be inclined in the horizontal direction, and for horizontal and vertical scanning from the rotating mirror. A second folding mirror for receiving the infrared rays received and reflecting the infrared rays in the horizontal direction; a second support column for supporting the second folding mirror and setting a horizontal inclination angle of the reflection surface; A horizontal adjusting mechanism provided on the back surface of the second folding mirror for finely adjusting the horizontal inclination angle of the folding mirror; and receiving infrared rays scanned from an optical scanning mechanism, as a thermal image signal. An infrared detector for output is provided, so that the part that spatially transmits the lines that are scanned horizontally and the part that spatially transmits the lines that are scanned vertically are viewed from the infrared detector. Completely independent In both cases, nothing intervenes on the optical path of infrared light from the window to the first turning mirror, and nothing intervenes on the optical path of infrared light from the rotating mirror to the second turning mirror. The fine adjustment of the optical axis of the light beam in the vertical direction and the horizontal direction is performed independently by the vertical and horizontal adjustment mechanisms provided on the back of the first and second folding mirrors, respectively. Since the adjustment can be performed, the adjustment does not take much time compared to the conventional one, the adjustment is easy, and the adjustment can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing an embodiment of the present invention.

FIG. 3 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a horizontal and vertical adjustment mechanism according to the embodiment of the present invention.

FIG. 5 is a perspective view of a main part showing a conventional example.

FIG. 6 shows an embodiment of the present invention and is an explanatory view of a sprite element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Subject 3 Infrared 4 Window 5 First folding mirror 6 Vibration mirror 7 Rotating mirror 8 Second folding mirror 10 Infrared detector (sprite element) 15 First support column 17 Vertical adjustment mechanism 24 Second Support column 26 Horizontal adjustment mechanism

Claims (1)

(57) [Claims] 1. A window which transmits only infrared rays radiated from the surface of a subject and a reflecting surface which is provided to be inclined in a vertical direction, receives the infrared rays transmitted through the window, and reflects the infrared rays in a vertical direction. A folded mirror, a first support column that supports the first folded mirror and sets a vertical inclination angle of the reflection surface, and is provided on a back surface of the first folded mirror, and is provided in a vertical direction. A vertical adjusting mechanism for finely adjusting the tilt angle of the mirror, a vibrating mirror for receiving the infrared rays from the first folding mirror and scanning in a vertical direction at a predetermined angle, and scanning in a vertical direction by the vibrating mirror. A rotating mirror for receiving the infrared rays and scanning the same in the horizontal direction; and a reflecting surface provided to be inclined in the horizontal direction, receiving the infrared rays horizontally and vertically scanned from the rotating mirror and receiving the infrared rays in the horizontal direction. Reflection A second mirror, a second support pillar for supporting the second mirror and setting a horizontal inclination angle of the reflection surface; and a second mirror provided on a back surface of the second mirror. And this folded mirror
A horizontal adjustment mechanism for fine-tuning the horizontal tilt angle of the camera, and an infrared detector for receiving infrared rays scanned from an optical scanning mechanism and outputting the same as a thermal image signal camera.