CN104570346A - Long-wave infrared optical imaging system for image stabilization indirectly based on image spaces - Google Patents

Abstract

The invention relates to a long-wave infrared optical imaging system based on image-side indirect image stabilization, which belongs to the field of optical guidance. In view of the large size of the existing three-axis stabilization platform used for tracking and image stabilization, which cannot meet the requirements of the supersonic seeker system for the miniaturization of the window, the system is sequentially equipped with a telescopic optical lens group, an oscillating mirror, Imaging optical mirror group and detector; the telescopic optical mirror group intersects with the optical axis of the imaging optical mirror group, and the optical path is connected through the swing mirror in the middle, and the swing mirror is driven by the rotating mechanism to swing in two directions of heading and pitching , reflecting the light beam within the field of view of the telescopic optical mirror group to the imaging optical mirror group, and converging on the detector through the imaging optical mirror group to generate an infrared image. The long-wave infrared optical imaging system provided by the present invention can realize the functions of the system to search for a target in a large field of view and track in a small field of view while satisfying the miniaturization of the system.

Description

A long-wave infrared optical imaging system based on image-side indirect image stabilization

technical field

The invention belongs to the technical field of optical guidance, and relates to a long-wave infrared optical imaging system, in particular to a long-wave infrared optical imaging system based on image-side indirect image stabilization.

Background technique

The infrared imaging guidance system is an important part of the supersonic seeker. It has the advantages of high guidance precision, strong anti-interference ability, and all-weather work. It is the key research object of military development in various countries in the world today. The miniaturized supersonic seeker is conducive to improving the maneuverability of guided weapons, increasing the payload of warheads, and enhancing the lethality of weapons, which will play an important role in the development of future military warfare. Therefore, how to realize the functions of large field of view search and small field of view tracking while ensuring the miniaturization of the infrared imaging guidance system has become one of the key points in the development of guided weapons today.

As shown in Figure 1, a traditional three-axis servo stabilization system includes a roll frame 1, a pitch frame 2, an azimuth frame 3, and an infrared thermal imaging camera 4, wherein the roll frame 1 is installed on the base along the Z-axis direction, around the Z-axis The pitch frame 2 is installed on the roll frame 1 along the X axis and rotates around the X axis; the azimuth frame 3 is mounted on the pitch frame 2 along the Y axis and rotates around the Y axis. They are respectively driven by a DC brushless torque motor Drive rotation. However, the three frames are epitaxial superimposed structures, and they are all rotary motion devices, which makes the three-axis stabilized platform system bulky and difficult to install and use in supersonic seeker systems that require miniaturized windows. CN103760670A discloses a large-field-of-view scanning infrared optical system containing a reflective spatial light modulator. The system consists of a double quadric surface correction plate, an achromatic rotating Resley prism pair, a beam splitting prism, a reflective spatial light modulator, etc. Arranged in sequence along the optical axis, the achromatic rotating Resley prism pair can scan a wide range of field of view, thereby realizing a large field of view search for the target; the beam splitter prism can bend the optical path, thereby reducing the volume of the optical system . However, the achromatic rotating Resley prism pair uses rotation to realize a large field of view scanning search, and it cannot adjust its heading and pitch angles according to the position of the discovered target so that the target is always located in the center of the imaging field of view, so the target cannot be searched. Small field of view range tracking. Therefore, how to realize the system's large field of view search and small field of view tracking while satisfying the miniaturization of the system has become one of the difficulties in the research of infrared imaging guidance systems.

Contents of the invention

Aiming at the large size of the existing three-axis stabilization platform used for tracking and image stabilization, which cannot meet the miniaturization requirements of the supersonic seeker system, the present invention provides a long-wave infrared optical imaging system based on image-side indirect image stabilization , while satisfying the miniaturization of the system, the system can realize the functions of large field of view search and small field of view tracking for the target.

The purpose of the present invention is achieved through the following technical solutions:

A long-wave infrared optical imaging system based on image-side indirect image stabilization, in which a telescopic optical mirror group, a swing mirror, an imaging optical mirror group, and a detector are sequentially arranged along the propagation direction of the optical path; the telescopic optical mirror group and the imaging optical mirror group The optical axes of the optical axes intersect, and the optical path is connected through the swing mirror in the middle. The swing mirror swings in the two directions of heading and pitch under the drive of the rotating mechanism, and reflects the beam within the field of view of the telescopic optical mirror group to the imaging optical mirror group. The infrared image is generated by converging on the detector through the imaging optical mirror group.

The existing three-axis stabilization platform used for tracking and image stabilization is too large to meet the requirements of the seeker system for the miniaturization of the window. Compared with the existing three-axis stabilized platform for tracking and image stabilization, the present invention has the following beneficial effects:

(1) The optical axes of the far optical lens group and the imaging optical lens group intersect and have a certain angle, and the optical path is connected through the swing mirror in the middle, which can meet the requirements of system miniaturization;

(2) The oscillating mirror swings in the heading and pitching directions to realize the large field of view scanning search for the target; after the target is found, under the control of the servo control system, the heading and pitching angle are continuously adjusted according to the attitude of the projectile, so that the target is always It is located in the center of the field of view of the imaging optical mirror group, so as to realize the small field of view tracking function of the target.

(3) The imaging optical mirror group adopts a secondary imaging optical path structure, and a mirror is added to the optical path to fold the optical path, so that the system size can be miniaturized.

Description of drawings

Fig. 1 is a structural diagram of a traditional servo stabilization system;

Fig. 2 is a structural diagram of a long-wave infrared optical imaging system;

Fig. 3 is a schematic diagram of the optical path of the long-wave infrared optical imaging system;

Fig. 4 is a comparison diagram of the field of view between the telescopic optical lens group and the imaging optical lens group.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered by the present invention. within the scope of protection.

The long-wave infrared optical imaging system is an important part of the supersonic seeker. Its structure is shown in Figure 2. It consists of a window 5, a telescopic optical mirror group 6, a swing mirror 7, an imaging optical mirror group 8 and a detector 9. . The positions of the telescopic optical lens group 6 and the imaging optical lens group 8 relative to the window 5 remain unchanged, their optical axes intersect and the angle is 104°, and the optical path is connected through the swing mirror 7 in the middle, so as to meet the requirements of system miniaturization.

The telescopic optical mirror group 6 comprises the first curved reflector 15, the second curved reflector 16 and the telescope group 14, wherein the telescope group 14 consists of the first lens 14-1, the second lens 14-2, the third lens 14-3 and the fourth lens 14-4. The telescopic optical lens group 6 is a large field of view optical system, and its field of view is 26.25°×28° (heading×pitch), covering the range of the tracking field of view. The telescopic optical lens group 6 is a telescopic system, which can project the light beam received in the tracking field of view to the position of the swing mirror 7 in the form of parallel light. The entrance pupil of the telescopic optical lens group 6 is close to the window 5, so that not only can the size of the window 5 be reduced, but also light blocking will not occur.

The imaging optical mirror group 8 includes a first imaging mirror group 10, a mirror 11 and a second imaging mirror group 12, wherein the first imaging mirror group 10 is composed of a fifth lens 10-1 and a sixth lens 10-2, and the second imaging mirror group 10 is composed of a fifth lens 10-1 and a sixth lens 10-2. Mirror group 12 is made up of the 7th lens 12-1, the 8th lens 12-2 and the 9th lens 12-3; Imaging optics mirror group 8 adopts the optical path structure of secondary imaging, and adds mirror in the optical path to make the optical path occur deflection, so that the system dimensions meet the requirements of miniaturization. The imaging optical mirror group 8 is a small field of view optical system, and its field of view is 6.25°×5° (heading×pitch). It scans and searches the 6 large fields of view of the telescopic optical lens group through the two-dimensional swing of the oscillating mirror 7, and performs tracking and imaging of the target in a small field of view after the target is found.

The swing mirror 7 is located between the telescopic optical lens group 6 and the imaging optical lens group 8, and its rotation angles in the azimuth direction and the pitch direction are ±5° and ±12° respectively. The installation method of the oscillating mirror 7 is that the included angle between the normal line of the oscillating mirror reflection surface and the optical axis of the telescopic optical mirror group 6 is 52° in the heading direction, and 0° in the pitching direction, which can meet the requirements of system miniaturization. The exit pupil of the telescopic optical mirror group 6 and the entrance pupil of the imaging optical mirror group 8 should be coupled at the position of the oscillating mirror 7, which can not only meet the requirement of miniaturization of the oscillating mirror size, but also avoid the imaging caused by the oscillating mirror 7 quality impact. Driven by the rotating mechanism, the swinging mirror 7 can swing in two directions of heading and pitching, so as to reflect the light beam within the field of view of the telescopic optical mirror group 6 to the imaging optical mirror group 8, so as to realize the large field of view search for the target Tracking with a small field of view.

As shown in Figure 3, the working process of the long-wave infrared optical imaging system is:

The telescopic optical lens group 6 receives the light beam emitted by the scene in the field of view of the object side. In the telescopic optical mirror group 6, the light beam successively passes through the continuous reflection of the first curved reflector 15 and the second curved reflector 16 and then enters the telescope group 14. After being collimated by the telescope group 14, it is projected to the position of the swing mirror 7 in the form of parallel light. The swinging mirror 7 reflects the light beam in the field of view of the telescopic optical lens group 6 to the imaging optical lens group 8 . In the imaging optical mirror group 8, the light beam is transmitted through the first imaging mirror group 10 and then incident on the mirror 11. The mirror 11 can deflect the optical path of the beam entering the imaging optical mirror group 8, so as to meet the miniaturization of the system. requirements. The deflected light beam passes through the second imaging mirror group 12 and finally converges on the photosensitive surface 13 of the detector to generate an infrared image, thereby realizing the functions of searching for a large field of view and tracking a target in a small field of view.

In the above-mentioned working process, since the field of view 17 of the telescopic optical lens group belongs to the large field of view (26.25°×28°) optical system, and the field of view 18 of the imaging optical lens group belongs to the small field of view (6.25°×5°) optical system, this As a result, the field of view of the imaging optical lens group cannot fill the entire field of view of the telescopic optical lens group, as shown in FIG. 4 . Therefore, in order to achieve a large field of view search for the target, the oscillating mirror 7 should swing in the two directions of heading and pitching, so as to reflect the light beams in different fields of view of the telescopic optical mirror group 6 to the imaging optical mirror group 8 . When the target is found, the swing mirror 7 is under the control of the servo control system to continuously adjust its inclination angle in the heading and pitching directions according to the attitude of the projectile, so that the target is always located in the center of the field of view of the imaging optical mirror group, so as to realize the accuracy of the target. Small field of view tracking.

Claims (7)

1. A long-wave infrared optical imaging system based on image side indirect image stabilization, characterized in that the system is successively provided with telescopic optical mirror group, swing mirror, imaging optical mirror group and detector along the propagation direction of the optical path; The optical axis of the optical mirror group intersects with the optical axis of the imaging optical mirror group, and the optical path is connected through the swing mirror in the middle. The light beam is reflected to the imaging optical mirror group, and converged to the detector through the imaging optical mirror group to generate an infrared image. 2. The long-wave infrared optical imaging system based on image-side indirect image stabilization according to claim 1, characterized in that the angle between the optical axes of the telescopic optical mirror group and the imaging optical mirror group is 104°. 3. The long-wave infrared optical imaging system based on image side indirect image stabilization according to claim 1, characterized in that the exit pupil of the telescopic optical mirror group and the entrance pupil of the imaging optical mirror group should be coupled at the position of the swing mirror. 4. The long-wave infrared optical imaging system based on image-side indirect image stabilization according to claim 1, 2 or 3, characterized in that the field of view of the telescopic optical lens group is 26.25°×28°. 5. The long-wave infrared optical imaging system based on image-side indirect image stabilization according to claim 1, 2 or 3, characterized in that the field of view of the imaging optical mirror group is 6.25°×5°. 6. The long-wave infrared optical imaging system based on image-side indirect image stabilization according to claim 1 or 3, characterized in that the rotation angles of the oscillating mirror in the heading and pitch directions are respectively ±5° and ±12°. 7. The long-wave infrared optical imaging system based on image-side indirect image stabilization according to claim 1 or 3, wherein the installation method of the swing mirror is that the normal line of the reflective surface of the swing mirror and the optical axis of the telescopic optical mirror group are within The included angle in the yaw direction is 52°, and the included angle in the pitch direction is 0°.