Scanning infrared optical system based on wedge-shaped lens

Abstract

The utility model provides a scanning infrared optical system based on wedge-shaped lenses, which comprises a wedge-shaped lens group used for scanning infrared radiation of a measured object and a lens group used for imaging the infrared radiation of the measured object, and the wedge-shaped lens group sequentially comprises a wedge-shaped lens I and a wedge-shaped lens II from the front side to the rear side along the trend of an optical path, the lens group sequentially comprises a lens I, a lens II and a lens III which are positioned behind the wedge-shaped lens II from the front side to the rear side along the trend of the light path; the beneficial effects of the utility model are that through the reverse rotation scanning of the wedge-shaped lens group, the operating distance requirement is met, and the view field requirement is also met; the wedge-shaped lens group is small in size and high in view field scanning speed, and does not cause deviation of an optical axis; and the wedge-shaped lens group has the advantages of small size and light weight, so that the scanning infrared optical system can be adapted to a 640 * 512 (15 [mu] m) F4 medium-wave refrigeration infrared detector, and is applied to a complex airborne alarm system as an infrared module.

Description

Technical Field

[0001] The utility model relates to the technical field of infrared thermal imaging, in particular to a scanning infrared optical system based on a wedge mirror. Background Art

[0002] The principle of a forward-looking infrared light imaging device mainly depends on an infrared detector, an optical imaging objective lens, and an opto-mechanical scanning system to receive the infrared radiation energy distribution pattern of the measured target and reflect it onto the photosensitive elements of the infrared detector. In this process, the opto-mechanical scanning mechanism is used to scan the infrared radiation of the measured object and focus it on the optical imaging objective lens, and then it is focused on a unit or a spectroscopic detector through the optical imaging objective lens. Subsequently, the detector converts the received infrared radiation energy into an electrical signal, and after amplification processing, conversion, or standard video signal, it is displayed through a computer or other display devices to form the infrared thermal image we see.

[0003] The existing forward-looking infrared light imaging device can quickly observe the left, right, and lower directions of the central field of view according to the pilot's operation to pre-inform the terrain and obstacles to be turned. The optical system has a large field of view, and at the same time, there are requirements for the working distance. Therefore, a single infrared lens cannot meet the requirements of both a large field of view and a long working distance. Summary of the Utility Model

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present utility model is to provide a scanning infrared optical system based on a wedge mirror to solve the problem that the existing single infrared lens cannot meet the requirements of both a large field of view and a long working distance at the same time.

[0005] To achieve the above purpose and other related purposes, the present utility model provides the following technical solutions:

[0006] A scanning infrared optical system based on a wedge mirror includes a wedge mirror group for scanning the infrared radiation of the measured object and a lens group for imaging the infrared radiation of the measured object. Among them, the wedge mirror group sequentially includes a first wedge mirror and a second wedge mirror from the front side to the rear side along the optical path direction, and the lens group sequentially includes a first lens, a second lens, and a third lens located behind the second wedge mirror from the front side to the rear side along the optical path direction. The wedge mirror group scans the infrared radiation of the measured object by reverse rotation.

[0007] In an embodiment of the present utility model, the wedge angles of the first wedge mirror and the second wedge mirror are the same. Among them, the size of the wedge angle depends on the size of the object-side scanning field of view. The size of the wedge angle in this technical solution depends on the size of the object-side scanning field of view, so that when the wedge mirror group scans the field of view, aberration will not be introduced.

[0008] In an embodiment of the present utility model, the materials of the first wedge mirror and the second wedge mirror are germanium. The wedge mirror group is driven by a motor to rotate in the reverse direction. Under the drive of the motor, the infrared radiation of the object to be measured is scanned through the reverse rotation of the wedge mirror group. This technical solution scans the infrared radiation of the object to be measured through the reverse rotation of the wedge mirror group driven by the motor, thereby realizing the deflection of the optical axis and further realizing the large field of view scanning.

[0009] In an embodiment of the present utility model, the lens group adopts a one-time imaging structure form. The material of the first lens is silicon, the material of the second lens is germanium, and the material of the third lens is silicon. In this technical solution, the lens group adopting the one-time imaging structure form can make the volume smaller. The materials of the lens group are silicon, germanium, and silicon in sequence, which can achieve better imaging quality and realize optical passive athermalization.

[0010] In an embodiment of the present utility model, a refrigerated detector is provided behind the third lens. The scanning infrared optical system can be adapted to a mid-wave refrigerated infrared detector with a resolution of 640×512, a pixel size of 15μm, and a cold screen F number of 4, and is applied as an infrared module in a complex airborne forward-looking infrared optoelectronic system.

[0011] As described above, a scanning infrared optical system based on a wedge mirror of the present utility model has the following beneficial effects:

[0012] The present utility model scans through the reverse rotation of the wedge mirror group, which not only meets the requirement of the action distance but also meets the requirement of the field of view. Moreover, the wedge mirror group has a small volume, a fast field of view scanning speed, and will not cause the deviation of the optical axis. In addition, the wedge mirror group has the advantages of small volume and light weight. Therefore, the scanning infrared optical system can be adapted to a 640×512(15μm)F4 mid-wave refrigerated infrared detector and be applied as an infrared module in a complex airborne warning system, and can realize large field of view scanning and long-distance detection. Description of the Drawings

[0013] Figure 1 It shows an optical schematic diagram of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present utility model;

[0014] Figure 2 It shows a 2D diagram of the 0-degree scanning field of view of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present utility model;

[0015] Figure 3 It shows a 2D diagram of the 15-degree scanning field of view of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present utility model;

[0016] Figure 4Shows a 2D diagram of the 30-degree scanning field of view of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present invention;

[0017] Figure 5 Shows the 0-degree scanning field of view @30 lp / mm MTF diagram of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present invention;

[0018] Figure 6 Shows the 15-degree scanning field of view @30 lp / mm MTF diagram of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present invention;

[0019] Figure 7 Shows the 30-degree scanning field of view @30 lp / mm MTF diagram of the scanning infrared optical system based on a wedge mirror disclosed in the embodiment of the present invention.

[0020] Description of component labels

[0021] 1. First wedge mirror; 2. Second wedge mirror; 3. First lens; 4. Second lens; 5. Third lens; 6. Refrigerated detector. Specific implementation manners

[0022] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0023] Please refer to Figures 1 to 7 , the present invention provides a scanning infrared optical system based on a wedge mirror. This scanning infrared optical system can achieve object-space field-of-view scanning in a limited space and belongs to the field of infrared thermal imaging. It includes a wedge mirror group for scanning the infrared radiation of the object to be measured and a lens group for imaging the infrared radiation of the object to be measured. Among them, the wedge mirror group sequentially includes a first wedge mirror 1 and a second wedge mirror 2 from the front side to the rear side along the optical path;

[0024] The wedge mirror group is driven by a motor to rotate in the reverse direction. Among them, when scanning the infrared radiation of the object to be measured, the first scanning method is: the first wedge mirror 1 remains stationary, and the second wedge mirror 2 rotates relative to the first wedge mirror 1 under the drive of the motor; the second scanning method is: the first wedge mirror 1 and the second wedge mirror 2 are respectively driven by two motors and rotate in opposite directions; under the drive of the motor, the reverse rotation of the wedge mirror group scans the infrared radiation of the object to be measured, which not only meets the requirement of the working distance but also meets the requirement of the field of view, thereby realizing the deflection of the optical axis and further realizing large-field-of-view scanning;

[0025] The wedge angles of the first wedge mirror 1 and the second wedge mirror 2 are the same. The size of the wedge angle depends on the size of the object-side scanning field of view. When the wedge mirror group scans the field of view, it will not introduce aberration. The materials of the first wedge mirror 1 and the second wedge mirror 2 are germanium. This wedge mirror group is small in volume, fast in field-of-view scanning speed, and will not cause the deviation of the optical axis. Behind the wedge mirror group is a passive athermalized fixed-focus lens, which can achieve long working-distance observation without focusing and can meet complex environmental changes.

[0026] The lens group includes a first lens 3, a second lens 4, and a third lens 5 in sequence from the front side to the rear side along the optical path direction, and a refrigerated detector 6 is provided behind the third lens 5. The lens group adopts a one-time imaging structure form, so that the volume of this scanning infrared optical system can be made smaller. The material of the first lens 3 is silicon, the material of the second lens 4 is germanium, and the material of the third lens 5 is silicon, that is, the materials of the lens group are silicon, germanium, and silicon in sequence, so that better imaging quality can be achieved and optical passive athermalization can be realized.

[0027] As can be seen from the above, the advantage of using the wedge mirror group for scanning is that there is no optical path folding, which is suitable for optical systems with extremely small space where other scanning devices cannot be placed, such as airborne forward-looking systems. In addition, this scanning infrared optical system has a large scanning angle and good imaging quality, can be adapted to a mid-wave refrigerated infrared detector with a resolution of 640×512, a pixel size of 15μm, and a cold shield F number of 4, and can be used as an infrared module in a complex airborne forward-looking infrared optoelectronic system to achieve large-field-of-view scanning and long-distance detection.

[0028] To sum up, the utility model scans in reverse rotation through the wedge mirror group, which not only meets the requirement of the working distance but also meets the requirement of the field of view. And the wedge mirror group is small in volume, fast in field-of-view scanning speed, and will not cause the deviation of the optical axis. Moreover, the wedge mirror group has the advantages of small volume and light weight. Therefore, this scanning infrared optical system can be adapted to a 640×512(15μm)F4 mid-wave refrigerated infrared detector and be used as an infrared module in a complex airborne warning system to achieve large-field-of-view scanning and long-distance detection, thus facilitating popularization and use.

[0029] The above embodiments only illustratively explain the principle and its effects of the utility model, rather than limiting the utility model. All equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the utility model should still be covered by the claims of the utility model.

Claims

1. A scanning infrared optical system based on a wedge mirror, characterized in that: It includes a wedge mirror group for scanning the infrared radiation of the object to be measured and a lens group for imaging the infrared radiation of the object to be measured. Among them, the wedge mirror group successively includes a first wedge mirror (1) and a second wedge mirror (2) from the front side to the rear side along the optical path direction. The lens group successively includes a first lens (3), a second lens (4), and a third lens (5) located behind the second wedge mirror (2) from the front side to the rear side along the optical path direction. The wedge mirror group scans the infrared radiation of the object to be measured by reverse rotation.

2. The scanning infrared optical system based on a wedge mirror according to claim 1, wherein: The wedge angles of the first wedge mirror (1) and the second wedge mirror (2) are the same. Among them, the size of the wedge angle depends on the size of the object space scanning field of view.

3. A scanning infrared optical system based on a wedge mirror according to claim 1, characterized in that: The materials of the first wedge mirror (1) and the second wedge mirror (2) are germanium. The wedge mirror group is driven by a motor to achieve reverse rotation. Under the drive of the motor, the infrared radiation of the object to be measured is scanned by the reverse rotation of the wedge mirror group.

4. The scanning infrared optical system based on a wedge mirror according to claim 1, characterized in that: The lens group adopts a one-time imaging structure form. The material of the first lens (3) is silicon, the material of the second lens (4) is germanium, and the material of the third lens (5) is silicon.

5. The scanning infrared optical system based on a wedge mirror according to claim 1, wherein: A refrigerated detector (6) is provided behind the third lens (5). The scanning infrared optical system can be adapted to a mid-wave refrigerated infrared detector with a resolution of 640×512, a pixel size of 15μm, and a cold shield F number of 4, and is applied as an infrared module in a complex airborne forward-looking infrared optoelectronic system.

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