CN114815199B - Large-view-field off-axis five-reflection non-axial zooming imaging optical system - Google Patents

Abstract

The invention discloses a large field of view off-axis five mirror non-axial zoom imaging optical system, which belongs to the field of optical zoom imaging. The main mirror of the present invention is a convex reflector, which diverges light rays with a large incident angle and helps to realize imaging with a large field of view. The secondary imaging structure is adopted, and the non-axial synchronous zoom primary imaging subsystem is based on the off-axis three-reflection axial zoom, and the zoom adjustment in the vertical axis direction is added to increase the degree of freedom in the optimization of the zoom imaging optical system; through the non-axial movement Realize the synchronous adjustment of axial movement and vertical axis movement, and realize non-axial synchronous zooming. The rear relay imaging subsystem realizes the inversion, transmission and zoom imaging of an intermediate image plane through two fixed mirrors. By re-imaging at the primary image plane, the field diaphragm can be set at the position of the primary image plane, which can significantly reduce the stray light caused by the difficulty of setting the light blocking device due to the movement of the mirror. The invention also has the following advantages: it does not need to use a free-form surface mirror, which reduces the cost of processing and testing.

Description

A large field of view off-axis five mirror non-axial zoom imaging optical system

technical field

The invention belongs to the field of optical zoom imaging, in particular to an off-axis reflective zoom imaging optical system with large relative aperture and large zoom ratio.

Background technique

In the field of remote sensing detection, the design of zoom optical system with wide spectrum, large zoom ratio and high resolution is of great significance. The off-axis total reflection zoom optical system has the characteristics of no chromatic aberration, wide imaging spectrum, large field of view search and small field of view aiming, and unobstructed imaging. It meets the application requirements of a new generation of high-performance, light and small airborne remote sensing payloads.

The off-axis total reflection zoom optical system is divided into active zoom type and mechanical zoom type according to the principle. The off-axis total reflection active zoom imaging system realizes the change of the optical power of the system by controlling the curvature of the active optical elements (deformable mirror, spatial light modulator, liquid lens, etc.). The off-axis total reflection active zoom imaging system has fast response speed and relatively small volume, but there are still limitations of high difficulty in adjusting the active optical components, high difficulty in off-axis surface fitting, slow data transmission speed, and high cost. The off-axis total reflection mechanical zoom imaging system realizes the change of the overall focal power by controlling the axial movement of the internal mirror of the system. Compared with the off-axis total reflection active zoom imaging system, the response speed is slower and the volume is larger. But the mechanical control is relatively simple and the cost is low. The traditional off-axis total reflection mechanical zoom imaging system generally adopts the structure of three mirrors and four mirrors. When the main mirror is a concave mirror, the field of view of the system is small. In addition, in order to achieve high-resolution imaging in a large zoom ratio range, the free-form surface mirror is used to correct the high-order asymmetric aberration of the system, but the processing and detection difficulties of the free-form mirror greatly increase the The difficulty and cost of developing such systems.

Contents of the invention

In order to overcome the shortcomings of the traditional off-axis total reflection mechanical zoom imaging system with relatively small aperture and complex surface shape, the main purpose of the present invention is to provide a large field of view off-axis five mirror non-axial zoom imaging optical system. The primary mirror is a convex mirror, which diverges light rays at large incident angles and helps to achieve large field of view imaging. The secondary imaging structure is adopted, that is, the five mirrors are divided into a non-axial synchronous zoom primary imaging subsystem and a rear relay imaging subsystem according to the imaging structure and function. On the basis of the off-axis three-reflection axial zoom, the non-axial synchronous zoom primary imaging subsystem adds zoom adjustment in the vertical axis direction to increase the degree of freedom in the optimization of the zoom imaging optical system; in addition, the axial movement is realized through the non-axial movement vector The synchronous adjustment with the vertical axis movement realizes the non-axial synchronous zoom of the zoom imaging optical system, thereby ensuring good imaging quality under different focal length states. The rear relay imaging subsystem realizes the inversion, transmission and zoom imaging of an intermediate image plane through two fixed mirrors. The primary image plane of the non-axial synchronous zoom primary imaging subsystem is imaged again through the relay imaging subsystem, and the field diaphragm can be set at the position of the primary image plane, which significantly reduces the difficulty of setting the light blocking device due to the movement of the mirror. The stray light from the sensor can effectively eliminate the stray light reaching the image surface of the detector. The invention also has the following advantages: it does not need to use a free-form surface mirror, which reduces the cost of processing and testing.

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

A large field of view off-axis five-mirror non-axial zoom imaging optical system disclosed by the present invention includes a primary reflector, a secondary reflector, a third reflector, a fourth reflector, a fifth reflector, and a detector image plane, It also includes a translation stage for moving the secondary mirror and the third mirror.

The primary reflector is a fixed reflector with a constant spatial position, and the secondary reflector and the third reflector are components of a zoom group and a compensation group, and zoom imaging is realized by moving the two reflectors non-axially. Wherein, the non-axial movement is realized based on a non-axial movement vector, and the non-axial movement vector is a non-axial movement vector composed of an axial movement amount and a vertical axis movement amount. The focal length of the non-axial zoom imaging optical system can be changed by axial movement; the degree of freedom of the zoom imaging optical system can be increased by moving in the vertical direction, and the effect of the eccentricity of the two mirrors on the aberration field can be used to actively balance the multiplicity of the zoom imaging optical system The wave aberration between the structures realizes the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures. The synchronous adjustment of the axial movement and the vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zoom of the zoom imaging optical system is realized, thereby ensuring good imaging quality under different focal length states, without using free-form surfaces.

Preferably, the main reflector is a convex reflector, which diverges light rays with a large incident angle, and helps to realize imaging with a large field of view.

As a preference, the active balance of the wave aberration between the multiple structures of the zoom imaging optical system by using the effect of the eccentricity of the two mirrors on the aberration field is implemented as follows:

Step 1, determine the axial movement of the two reflectors according to the axial movement formula (1).

Among them, r is the radius of curvature of the mirror, t is the distance between the mirrors, α _ji is the obscuration ratio, β _ji is the magnification, and f _j is the focal length under different structures.

Step 2: Determine the primary wave aberration coefficient of the zoom imaging optical system according to formula (2), and the primary wave aberration coefficient is a function of α _ji , β _ji , f _j .

in:

Wherein: said _ki is the quadric surface coefficient of mirror i, and

n _i =1 (i is an odd number), n _i =-1 (i is an even number), n _i '=-1 (i is an odd number), n _i '=1 (i is an even number) (5)

u _j1 ＝0, u _j1 '＝2h _j1 /r ₁ , u _j2 ＝u _j1 ', u _j2 '＝u _j2 /β _j1 , u _j3 ＝u _j2 ', u _j3 '＝u _j3 /β _j2 (6 )

Step 3, based on the primary wave aberration coefficient of the zoom imaging optical system determined in step 2, determine the eccentricity σ _ji of the mirror under different structures through formula (7), and actively balance the zoom imaging optical system according to the eccentricity σ _ji The wave aberration between multiple structures realizes the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures. The difference Δσ _j2 and Δσ _j3 of the eccentricity σ _ji is the vertical axis movement of the three mirrors.

Wherein: the vertical axis movement amount is represented by the difference in eccentricity σ _ji of the reflectors in different structures, where j represents the jth structure, and i represents the ith reflector. As shown in formula (7), the coma center and astigmatism center of the off-axis zoom imaging system are always about The function of the vertical axis is added to the axial movement to increase the degree of freedom of the system, and the wave image between the multiple structures of the zoom system is actively balanced by using the effect of the off-axis system offset on the aberration field Difference.

The fourth reflector and the fifth reflector constitute a relay imaging subsystem with a magnification of b, and the spatial position is unchanged, so its curvature radius and thickness parameters can be calculated independently. It is defined that the magnification rate of the fourth reflector is β ₄ , the magnification rate of the fifth reflector is β ₅ , and β ₄ β ₅ =b is satisfied.

The relay imaging subsystem composed of the fourth mirror and the fifth mirror performs re-imaging on the primary image plane of the non-axial synchronous zoom primary imaging subsystem. In order to ensure that the imaging is clear and free of stray light, as a preference, the The field diaphragm is set at the position of the image plane, which greatly reduces the stray light caused by the movement of the mirror and it is difficult to install the light blocking device, thus effectively eliminating the stray light that can reach the image plane of the detector.

In order to ensure the stable imaging of the zoom imaging optical system, as a preference, the magnifications of the secondary reflector and the third reflector satisfy the zoom relationship that the conjugate distance is constant, so as to ensure that the position of the primary intermediate image plane remains unchanged, thereby ensuring that the detector image plane set unchanged.

Preferably, the primary reflector is a convex reflector, the secondary reflector, the third reflector, the fourth reflector and the fifth reflector are concave reflectors, and the surface types of the five reflectors are all 8-order aspherical surfaces. The reflective surfaces of the primary reflector and the secondary reflector are arranged oppositely, the reflective surfaces of the secondary reflector and the third reflector are arranged oppositely, the reflective surfaces of the third reflector and the fourth reflector are arranged oppositely, and the reflective surfaces of the fourth reflector and the fifth reflector are arranged oppositely. The reflective surfaces of the mirrors are arranged oppositely, and the fifth reflective mirror is arranged oppositely to the image surface of the detector.

The reflective surfaces of the primary reflector and the secondary reflector are arranged oppositely, the reflective surfaces of the secondary reflector and the third reflector are arranged oppositely, the reflective surfaces of the third reflector and the fourth reflector are arranged oppositely, the fourth reflector and the fifth reflector are arranged oppositely The reflective surface of the reflective mirror is arranged oppositely, and the fifth reflective mirror is arranged oppositely to the image surface of the detector. The primary reflector, the secondary reflector, the third reflector, the fourth reflector and the fifth reflector are placed eccentrically and obliquely relative to the optical axis, and the eccentricity and inclination of each mirror are different.

The working method of a large field of view off-axis five mirror non-axial zoom imaging optical system disclosed by the present invention is as follows:

The light from the target is incident on the reflective surface of the primary reflector, and the first reflected light is formed after being reflected by the reflective surface of the primary reflector, and the first reflected light is incident on the reflective surface of the secondary reflector, The second reflected light is formed after being reflected by the reflecting surface of the secondary reflecting mirror, the second reflected light is incident on the reflecting surface of the third reflecting mirror, and the third reflected light is formed after being reflected by the reflecting surface of the third reflecting mirror, The third reflected light is incident on the reflective surface of the fourth reflective mirror, and is reflected by the reflective surface of the fourth reflective mirror to form fourth reflected light, and the fourth reflected light is incident on the reflective surface of the fifth reflective mirror. On the surface, the fifth reflected light is formed after being reflected by the reflecting surface of the fifth reflecting mirror, and the fifth reflected light is received and imaged by the image surface of the detector. For example, when the secondary reflector and the third reflector are located at the specified positions, the system can clearly image a large field of view. When the secondary reflector and the third reflector move to the corresponding positions non-axially, the system switches to a smaller field of view. The telephoto state enables clear imaging of objects in a larger field of view with higher spatial resolution on the object side.

The synchronous adjustment of the axial movement and the vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zoom of the zoom imaging optical system is realized. Use the rear relay imaging subsystem to re-image the primary intermediate image, and add a field diaphragm at the position of the stable primary intermediate image plane, which can effectively eliminate the stray light entering the rear relay imaging subsystem and the detector image plane . Through the above settings, the imaging quality is guaranteed to be good under different focal lengths, without using free-form surfaces.

Beneficial effect:

1. A large field of view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention, the main reflector, the fourth reflector and the fifth reflector are fixed reflectors, the secondary reflector and the third reflector are The movable reflector, and the primary reflector, the secondary reflector and the third reflector form a non-axial synchronous zoom primary imaging subsystem, and the fourth reflector and the fifth reflector form a rear relay imaging subsystem. Zooming is realized by changing the optical power of the mirror group by non-axially moving the primary reflector, the secondary reflector and the third reflector. The rear relay imaging subsystem realizes the inversion, transmission and zoom imaging of an intermediate image plane through two fixed mirrors. By adding a field diaphragm at the position of the primary intermediate image plane, the stray light entering the rear relay imaging subsystem can be effectively eliminated. The synchronous adjustment of the axial movement and the vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zoom of the zoom imaging optical system is realized, thereby ensuring good imaging quality under different focal length states, without using free-form surfaces.

2. The present invention discloses a large field of view off-axis five mirror non-axial zoom imaging optical system, the non-axial movement vector is the non-axial movement vector composed of the axial movement amount and the vertical axis movement amount. The focal length of the non-axial zoom imaging optical system can be changed by axial movement; the degree of freedom of the zoom imaging optical system can be increased by moving in the vertical direction, and the effect of the eccentricity of the two mirrors on the aberration field can be used to actively balance the multiplicity of the zoom imaging optical system The wave aberration between the structures realizes the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures.

3. The present invention discloses a large field of view off-axis five-mirror non-axial zoom imaging optical system. According to Seidel's aberration theory and vector aberration theory, a correction method for high-order astigmatism and coma of the zoom imaging optical system is established. , using the effect of the eccentricity of the two mirrors on the aberration field to actively balance the wave aberration between the multiple structures of the zoom imaging optical system, and realize the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures .

4. The present invention discloses a large field of view off-axis five-mirror non-axial zoom imaging optical system. By setting the field diaphragm at the stable primary image plane, it can greatly reduce the cost of the non-axial synchronous zoom primary imaging subsystem. The stray light that cannot be eliminated due to the movement of the mirror effectively eliminates the stray light that can reach the image surface of the detector.

5. A large-field-of-view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention, by setting the main mirror as a convex mirror, the rays of light at a large incident angle are diverged, which helps to realize large-field imaging

5. The large field of view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention only needs to use high-order aspheric mirrors and does not need to use free-form mirrors, which reduces processing and testing costs.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the device of the present invention.

Figure 2 is a schematic diagram of the space coordinate system.

Fig. 3 is a short-focus state optical path diagram of the device of the present invention.

Fig. 4 is an optical path diagram of the telephoto state of the device of the present invention.

Among them, 01-primary reflector, 02-secondary reflector, 03-third reflector, 04-fourth reflector, 05-fifth reflector, 06-detector image plane.

Detailed ways

In order to better illustrate the purpose and advantages of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and examples.

As shown in Figure 1, the main purpose of the present invention is to provide a large field of view off-axis five-mirror non-axial zoom imaging optical system, including a primary reflector 01, a secondary reflector 02, a third reflector 03, and a fourth reflector 04, the fifth mirror 05, and the detector image plane 06.

The system is located in a space coordinate system (XYZ), and the directions of the coordinate axes are shown in FIG. 2 .

The main reflector 01 is a convex reflector with an 8th-order aspherical surface and a constant spatial position, and is used for divergent reflection of light from a large field of view of the target to form the first reflected light.

The secondary reflector 03 is a concave reflector with an 8-order aspheric surface, and is used to reflect the light from the primary reflector 02 again to form the second reflected light.

The third reflector 03 is a concave reflector with an 8-order aspheric surface, and is used to focus and image the light from the secondary reflector 03 on the primary image plane to form the third reflected light.

The fourth reflector 05 is a concave reflector with an 8-order aspheric surface, and is used to reflect the light from the third reflector 03 to form fourth reflected light.

The fifth reflector 06 is a concave reflector with an 8-order aspherical surface, and is used to focus and image the light from the fourth reflector 05 on the target surface of the detector 07 .

The secondary reflector 02 and the third reflector 03 are moved to designated positions through the translation stage.

The primary mirror 01, secondary mirror 02, and third mirror 03 form a non-axial synchronous zoom primary imaging subsystem, and the fourth mirror 04 and fifth mirror 05 form a relay imaging with a magnification of 1 subsystem.

The relay imaging subsystem re-images the primary image plane of the non-axial synchronous zoom primary imaging subsystem. As a preference, the field diaphragm can be set at the position of the primary image plane, which greatly reduces the difficulty in setting due to the movement of the mirror. The stray light brought by the light blocking device can effectively eliminate the stray light that can reach the image surface of the detector.

The secondary reflector 02 and the third reflector 03 are components of the variable power group and the compensation group, and the change of the focal length of the system is realized by moving the two mirrors non-axially, and the zoom ratio is 4 times.

The magnification of the secondary reflector 02 and the third reflector 03 satisfies the zoom relationship that the conjugate distance is constant, so that the position of the primary intermediate image plane remains unchanged, thereby ensuring that the position of the detector image plane 06 remains unchanged.

Wherein, the non-axial movement is realized based on a non-axial movement vector, and the non-axial movement vector is a non-axial movement vector composed of an axial movement amount and a vertical axis movement amount. The focal length of the non-axial zoom imaging optical system can be changed by axial movement; the degree of freedom of the zoom imaging optical system can be increased by moving in the vertical direction, and the effect of the eccentricity of the two mirrors on the aberration field can be used to actively balance the multiplicity of the zoom imaging optical system The wave aberration between the structures realizes the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures. The synchronous adjustment of the axial movement and the vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zoom of the zoom imaging optical system is realized, thereby ensuring good imaging quality under different focal length states, without using free-form surfaces.

The non-axial movement of the secondary reflector 02 and the third reflector 03 is a one-dimensional movement in the YZ plane, which can be decomposed into an axial (Z direction) movement component and a vertical axis (Y direction) movement component, specifically It can be shown that under different focal length states, the distance from the secondary reflector 02 and the third reflector 03 to the previous reflector is different and the Y-axis eccentricity of the secondary reflector 02 and the third reflector 03 is different. Among them, the change of the focal length of the system is realized by moving in the axial direction (Z direction), and the correction of high-order astigmatism and coma aberration under different focal length structures of the system is realized by moving in the vertical axis (Y direction), so as to ensure the imaging quality under different focal length states Good, no need to use freeform surfaces.

The general expression for an 8th-order aspheric surface is:

In the formula, z is the vector height of the surface, c is the curvature of the surface, k is the coefficient of the quadratic surface, and α _i is the coefficient of the ith term in the polynomial.

According to the implementation method disclosed in this embodiment to actively balance the wave aberration between the multiple structures of the zoom imaging optical system by using the effect of the eccentricity of the two mirrors on the aberration field, and the surface parameters and non-axis parameters of the mirror determined by subsequent optimization The amount of movement is as follows:

In this embodiment, the radius r of the reflecting surface of the main reflector 01, the secondary reflector 02, the third reflector 03, the fourth reflector 04 and the fifth reflector 05 is the reciprocal of the curvature c, and the quadric surface coefficient k , and the values of various coefficients α _i are shown in Table 1 respectively. It can be understood that the values of the radius r, quadric surface coefficient k, and various coefficients α _i are not limited to those described in Table 1, and those skilled in the art can adjust them according to actual needs.

Table 1 Surface parameters of primary reflector 01, secondary reflector 02, third reflector 03, fourth reflector 04 and fifth reflector 05

The spatial positions of the secondary reflector 02 and the third reflector 03 in the short-focus and long-focus states are shown in Table 2. It can be understood that the distance between lenses and the values of lens eccentricity are not limited to those described in Table 2, and those skilled in the art can adjust according to actual needs.

Table 2 Spatial position parameters of secondary reflector 02 and third reflector 03

The primary reflector 01 , secondary reflector 02 , third reflector 03 , fourth reflector 04 , and fifth reflector 05 can use aluminum alloy, beryllium aluminum alloy, silicon carbide and other materials as processing substrates. In order to improve the reflectivity of the main reflector 01, the secondary reflector 02, the third reflector 03, the fourth reflector 04, and the fifth reflector 05, silver film or gold film can be coated on their respective reflective surfaces to increase reflection. membrane.

The working optical path of the large field of view off-axis five mirror non-axial zoom imaging optical system is as follows: the light from the target is incident on the reflection surface of the main reflector 01, and is reflected by the reflection surface of the main reflector 01 to form The first reflected light, the first reflected light is incident on the reflective surface of the secondary reflector 02, and is reflected by the reflective surface of the secondary reflector 02 to form the second reflected light, and the second reflected light is incident on the first reflected light On the reflective surface of the three reflectors 03, the third reflected light is formed after being reflected by the reflective surface of the third reflector 03, and the third reflected light is incident on the reflective surface of the fourth reflector 04, and passes through the fourth reflected light. The fourth reflected light is formed after being reflected by the reflecting surface of the reflecting mirror 04, and the fourth reflected light is incident on the reflecting surface of the fifth reflecting mirror 05, and is reflected by the reflecting surface of the fifth reflecting mirror 05 to form the fifth reflected light , the fifth reflected light is received by the image plane 06 of the detector and imaged. As shown in Figure 3, it is a schematic diagram of the short-focus state of the system. When the secondary mirror 02 and the third mirror 03 are located at the specified positions, the system can clearly image a large field of view. When the secondary mirror 02 and the third mirror 03 are respectively When the axis moves to the corresponding position shown in Figure 4, the system switches to the telephoto state with 4 times magnification to perform clear imaging of objects in a larger field of view with higher object space resolution.

The large field of view off-axis five mirror non-axial zoom imaging optical system provided by the embodiment of the present invention has the following advantages:

1. A large field of view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention, the main reflector, the fourth reflector and the fifth reflector are fixed reflectors, the secondary reflector and the third reflector are The movable reflector, and the primary reflector, the secondary reflector and the third reflector form a non-axial synchronous zoom primary imaging subsystem, and the fourth reflector and the fifth reflector form a rear relay imaging subsystem. Zooming is realized by changing the optical power of the mirror group by non-axially moving the primary reflector, the secondary reflector and the third reflector. The rear relay imaging subsystem realizes the inversion, transmission and zoom imaging of an intermediate image plane through two fixed mirrors. By adding a field diaphragm at the position of the primary intermediate image plane, the stray light entering the rear relay imaging subsystem can be effectively eliminated. The synchronous adjustment of the axial movement and the vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zoom of the zoom imaging optical system is realized, thereby ensuring good imaging quality under different focal length states, without using free-form surfaces.

2. The present invention discloses a large field of view off-axis five mirror non-axial zoom imaging optical system, the non-axial movement vector is the non-axial movement vector composed of the axial movement amount and the vertical axis movement amount. The focal length of the non-axial zoom imaging optical system can be changed by axial movement; the degree of freedom of the zoom imaging optical system can be increased by moving in the vertical direction, and the effect of the eccentricity of the two mirrors on the aberration field can be used to actively balance the multiplicity of the zoom imaging optical system The wave aberration between the structures realizes the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures.

3. The present invention discloses a large field of view off-axis five-mirror non-axial zoom imaging optical system. According to Seidel's aberration theory and vector aberration theory, a correction method for high-order astigmatism and coma of the zoom imaging optical system is established. , using the effect of the eccentricity of the two mirrors on the aberration field to actively balance the wave aberration between the multiple structures of the zoom imaging optical system, and realize the correction of high-order astigmatism and coma in the non-axial zoom imaging optical system under different focal length structures .

4. The present invention discloses a large field of view off-axis five-mirror non-axial zoom imaging optical system. By setting the field diaphragm at the stable primary image plane, it can greatly reduce the cost of the non-axial synchronous zoom primary imaging subsystem. The stray light that cannot be eliminated due to the movement of the mirror effectively eliminates the stray light that can reach the image surface of the detector.

5. A large-field-of-view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention, by setting the main mirror as a convex mirror, the rays of light at a large incident angle are diverged, which helps to realize large-field imaging

5. The large field of view off-axis five-mirror non-axial zoom imaging optical system disclosed in the present invention only needs to use high-order aspheric mirrors and does not need to use free-form mirrors, which reduces processing and testing costs.

To sum up, the above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. The utility model provides a big visual field off-axis five anti-non-axial zoom imaging optical system which characterized in that: the detector comprises a main reflector, a secondary reflector, a third reflector, a fourth reflector, a fifth reflector and a detector image surface, and also comprises a translation stage for moving the secondary reflector and the third reflector;

the main reflector is a fixed reflector, the space position is unchanged, the secondary reflector and the third reflector are respectively a variable-magnification group and a compensation group element, and the secondary reflector and the third reflector are axially moved to realize zoom imaging; the non-axial movement is realized based on a non-axial movement vector, and the non-axial movement vector is a non-axial movement vector formed by combining axial movement amount and vertical movement amount; the change of the focal length of the non-axial zooming imaging optical system is realized through axial movement; the freedom degree of the zoom imaging optical system is increased through the vertical axis direction movement, wave aberration among multiple structures of the zoom imaging optical system is actively balanced by utilizing the action of the eccentric amounts of the secondary reflector and the third reflector on the aberration field, and the correction of high-order astigmatism and coma aberration of the non-axial zoom imaging optical system under different focal length structures is realized; synchronous adjustment of axial movement and vertical axis movement is realized through a non-axial movement vector, and non-axial synchronous zooming of a zooming imaging optical system is realized, so that good imaging quality in different focal length states is ensured, and a free-form surface is not required to be used;

the main reflector is a convex reflector, diverges light rays with a large incident angle, and is beneficial to realizing large-view-field imaging;

the relay imaging subsystem composed of the fourth reflecting mirror and the fifth reflecting mirror images the primary intermediate imaging surface of the non-axial synchronous zooming primary imaging subsystem composed of the main reflecting mirror, the secondary reflecting mirror and the third reflecting mirror again, and in order to ensure that imaging is clear and free of stray light, a view field diaphragm is arranged at the position of the primary intermediate imaging surface, stray light caused by the fact that the reflecting mirror moves and a light blocking device is difficult to set is reduced, and therefore stray light which can reach the imaging surface of the detector is effectively eliminated.

2. A large field of view off-axis five-way non-axial zoom imaging optical system as defined in claim 1, wherein: in order to ensure stable imaging of the zoom imaging optical system, the magnification of the secondary reflector and the magnification of the third reflector meet the zoom relation with invariable conjugate distance, and the primary intermediate image surface position is invariable, so that the image surface of the detector is invariable.

3. A large field of view off-axis five-way non-axial zoom imaging optical system as defined in claim 1, wherein: the main reflector is a convex reflector, the secondary reflector, the third reflector, the fourth reflector and the fifth reflector are concave reflectors, and the five reflectors are all 8-order aspheric surfaces; the primary and secondary mirrors are arranged with respect to each other, the secondary and third mirrors are arranged with respect to each other, the third and fourth mirrors are arranged with respect to each other, the fourth and fifth mirrors are arranged with respect to each other, and the fifth mirror is arranged with respect to the detector image plane.

4. A large field of view off-axis five-way non-axial zoom imaging optical system as defined in claim 1, wherein: the reflecting surfaces of the secondary reflecting mirror of the main reflecting mirror are arranged oppositely, the reflecting surfaces of the secondary reflecting mirror and the third reflecting mirror are arranged oppositely, the reflecting surfaces of the third reflecting mirror and the fourth reflecting mirror are arranged oppositely, the reflecting surfaces of the fourth reflecting mirror and the fifth reflecting mirror are arranged oppositely, and the image surfaces of the fifth reflecting mirror and the detector are arranged oppositely; the main reflector, the secondary reflector, the third reflector, the fourth reflector and the fifth reflector are all arranged eccentrically and obliquely to the optical axis, and the eccentric amount and the oblique amount of each reflector are different.

5. A large field of view off-axis five-inverse non-axial zoom imaging optical system as defined in claim 1, 2, 3 or 4, wherein: the working method is that,

light from a target is incident on the reflecting surface of the main reflecting mirror, forms first reflected light after being reflected by the reflecting surface of the main reflecting mirror, the first reflected light is incident on the reflecting surface of the secondary reflecting mirror, forms second reflected light after being reflected by the reflecting surface of the secondary reflecting mirror, the second reflected light is incident on the reflecting surface of the third reflecting mirror, forms third reflected light after being reflected by the reflecting surface of the third reflecting mirror, the third reflected light is incident on the reflecting surface of the fourth reflecting mirror, forms fourth reflected light after being reflected by the reflecting surface of the fourth reflecting mirror, the fourth reflected light is incident on the reflecting surface of the fifth reflecting mirror, forms fifth reflected light after being reflected by the reflecting surface of the fifth reflecting mirror, and the fifth reflected light is received and imaged by the detector image surface; when the secondary reflector and the third reflector are positioned at the designated positions, the system can perform clear imaging on a large view field, and when the secondary reflector and the third reflector are respectively moved to the corresponding positions in a non-axial direction, the system is switched to a long focal state with a smaller view field, and objects in the range of the view field are subjected to clear imaging with higher object space resolution;

synchronous adjustment of axial movement and vertical axis movement is realized through a non-axial movement vector, so that non-axial synchronous zooming of a zooming imaging optical system is realized; the rear relay imaging subsystem formed by the fourth reflecting mirror and the fifth reflecting mirror is utilized to re-image the primary intermediate image, and stray light entering the rear relay imaging subsystem and the image surface of the detector can be effectively eliminated by adding a field stop at the position of the stable primary intermediate image surface; through the arrangement, good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.