CN114815200B - Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system - Google Patents
Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system Download PDFInfo
- Publication number
- CN114815200B CN114815200B CN202210373899.6A CN202210373899A CN114815200B CN 114815200 B CN114815200 B CN 114815200B CN 202210373899 A CN202210373899 A CN 202210373899A CN 114815200 B CN114815200 B CN 114815200B
- Authority
- CN
- China
- Prior art keywords
- reflecting
- mirror
- reflector
- axial
- imaging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
- G02B17/02—Catoptric systems, e.g. image erecting and reversing system
- G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
- G02B17/0647—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using more than three curved mirrors
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
- G02B17/02—Catoptric systems, e.g. image erecting and reversing system
- G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
Abstract
The invention discloses a large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system, and belongs to the field of optical zoom imaging. According to the invention, a secondary imaging structure is adopted, and a non-axial synchronous zooming primary imaging subsystem adds vertical-axis direction zooming adjustment on the basis of off-axis three-reflection full-type zooming, so that the optimization degree of freedom of a zooming imaging optical system is increased; the synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized. The rear relay imaging subsystem realizes the overturn, transmission and zoom imaging of an intermediate image plane through two fixed reflectors. The relay imaging subsystem is used for imaging the primary image surface again, and the view field diaphragm is arranged at the position of the primary image surface, so that stray light caused by the fact that the light blocking device is difficult to arrange due to the movement of the reflecting mirror is obviously reduced, and stray light reaching the image surface of the detector is effectively eliminated. The invention does not need to use a free-form surface reflecting mirror, and reduces the processing and detecting cost.
Description
Technical Field
The invention belongs to the field of optical zoom imaging, and particularly relates to an off-axis reflection zoom imaging optical system with large relative aperture and large zoom ratio.
Background
In the field of airborne earth observation, the design of a wide-spectrum, large-zoom-ratio and high-resolution zoom optical system has important significance. The off-axis total reflection type zoom optical system has the characteristics of no chromatic aberration wide imaging spectrum, large view field searching, small view field aiming and no obscuration imaging, and meets the application requirements of the new generation of high-performance light and small airborne earth observation load.
Off-axis total reflection type zoom optical systems are classified into an active zoom type and a mechanical zoom type according to principles. Off-axis total reflection type active zoom imaging systems realize the change of system focal power by controlling the change of curvature and the like of active optical elements (deformable mirrors, spatial light modulators, liquid lenses and the like). The off-axis total reflection type active zooming imaging system has the advantages of high response speed and relatively small volume, but the limitations of high difficulty in adjusting and controlling an active optical element, high difficulty in fitting off-axis surface type, low data transmission speed and high cost still exist. The off-axis total reflection type mechanical zooming imaging system realizes the change of the overall focal power by controlling the axial movement of the internal reflector of the system, and compared with the off-axis total reflection type active zooming imaging system, the off-axis total reflection type mechanical zooming imaging system has the advantages of slower response speed, larger volume, relatively simple mechanical control and lower cost. The traditional off-axis total reflection type mechanical zooming imaging system generally adopts a structure of three reflectors and four reflectors, can realize zooming imaging with large zoom ratio, but has an entrance pupil diameter with a fixed size, has smaller relative aperture, particularly in a long focal state, has extremely small relative aperture, and is difficult to meet the requirement of high resolution imaging. In addition, in order to realize high resolution imaging in a large zoom ratio range, the free-form surface type reflecting mirror is used for correcting high-order asymmetric aberration of the system, but the processing difficulty and the detection difficulty of the free-form surface reflecting mirror are high, so that the development difficulty and the cost of the system are greatly increased.
Disclosure of Invention
In order to overcome the defects of small relative aperture and complex surface shape of the traditional off-axis total reflection type mechanical zoom imaging system, the invention mainly aims to provide the off-axis five-reflection non-axial zoom imaging optical system with large relative aperture. The structure of secondary imaging is adopted, namely, five reflectors are divided into a non-axial synchronous zooming primary imaging subsystem and a rear relay imaging subsystem according to imaging structures and functions. The non-axial synchronous zooming initial imaging subsystem adds vertical-axis direction zooming adjustment on the basis of off-axis three-reflection type full-motion zooming, so that the optimization degree of freedom of the zooming imaging optical system is increased; in addition, the synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, so that the non-axial synchronous zooming of the zooming imaging optical system is realized, and the good imaging quality under different focal length states is ensured. The rear relay imaging subsystem realizes the overturn, transmission and zoom imaging of an intermediate image plane through two fixed reflectors. The relay imaging subsystem is used for re-imaging the primary image surface of the non-axial synchronous zooming primary imaging subsystem, a view field diaphragm can be arranged at the position of the primary image surface, stray light caused by the fact that a light blocking device is difficult to arrange due to the fact that a reflecting mirror moves is remarkably reduced, and therefore stray light reaching the image surface of the detector is effectively eliminated. The invention also has the following advantages: and a free-form surface reflecting mirror is not required, so that the processing and detecting cost is reduced.
The invention aims at realizing the following technical scheme:
the invention discloses a large relative aperture off-axis five-reflection non-axial zoom imaging optical system which comprises an iris diaphragm, 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 main reflector, the secondary reflector and the third reflector.
The iris diaphragm is an aperture diaphragm, and the aperture of the aperture diaphragm changes along with the change of the focal length. By adjusting the aperture of the aperture diaphragm, the relative aperture of the zooming imaging optical system is ensured to be fixed.
The main reflector, the secondary reflector and the third reflector are zoom group and compensation group elements, and zoom imaging is realized by non-axial movement of the three reflectors. 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 an axial movement amount and a 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 by the movement in the vertical axis direction, wave aberration among multiple structures of the zoom imaging optical system is actively balanced by utilizing the effect of eccentric amounts of the three reflectors of the main reflector, the secondary reflector and the third reflector on an 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. The synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized, so that good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.
Preferably, the method for actively balancing wave aberration among multiple structures of the zoom imaging optical system by utilizing the effect of the eccentric amounts of the three reflectors on the aberration field is as follows:
step one, determining the axial movement amount of the three reflectors according to an axial movement formula (1).
Wherein r is the radius of curvature of the mirrors, t is the distance between the mirrors, α ji Beta as the ratio of the obscuration ji For the magnification, f j Is the focal length under different structures.
Step two, determining a primary wave aberration coefficient of the zoom imaging optical system according to the formula (2), wherein the primary wave aberration coefficient is related to alpha ji ,β ji ,f j Is a function of (2).
Wherein:
wherein: the k is i Is the quadric surface coefficient of the reflector i, and
n i =1 (i is odd), n i = -1 (i is even), n i ' = -1 (i is an odd number), n i ' =1 (i is even) (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 three, based on the primary wave aberration coefficient of the zoom imaging optical system determined in the step two, passing through a common lensDetermining the eccentric amount sigma of the reflecting mirror under different structures ji And according to the eccentric amount sigma ji Wave aberration among multiple structures of the zooming imaging optical system is actively balanced, and high-order astigmatism and coma aberration of the non-axial zooming imaging optical system under different focal length structures are corrected. The eccentric amount sigma ji The difference DeltaSigma of (1) j1 ,△σ j2 ,△σ j3 Namely the vertical axis movement amount of the three reflectors.
Wherein: the vertical axis movement is expressed as the eccentric value sigma of the reflecting mirror with different structures ji Differently, where j represents the j-th reconstruction and i represents the i-th mirror. As shown in formula (7), the coma and astigmatism centers of the off-axis zoom imaging system are always relative to α ji ,β ji ,f j ,Adding vertical axis direction movement based on axial movement, increasing the degree of freedom of the system, and actively balancing wave aberration among multiple structures of the zoom system by utilizing the action characteristic of off-axis system offset on aberration fields.
The fourth reflecting mirror and the fifth reflecting mirror form a relay imaging subsystem with the magnification of b, and the space position is unchanged, so that the curvature radius and thickness parameters of the relay imaging subsystem can be calculated independently. Definition of the magnification of the fourth mirror as beta 4 The magnification of the fifth reflector is beta 5 And meet beta 4 β 5 ＝b。
The relay imaging subsystem formed by the fourth reflecting mirror and the fifth reflecting mirror performs re-imaging on the primary image surface of the non-axial synchronous zooming primary imaging subsystem, and in order to ensure that imaging is clear and free of stray light, a view field diaphragm is preferably arranged at the position of the primary image surface, so that stray light caused by the difficulty in arranging a light blocking device due to the movement of the reflecting mirror is obviously reduced, and stray light which can reach the image surface of the detector is effectively eliminated.
Preferably, the main mirror, the third mirror, the fourth mirror and the fifth mirror are concave mirrors, the sub-mirror is a convex mirror, and the five mirrors 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. The iris diaphragm and the mirror surface center of the main mirror are eccentrically arranged along the Y-axis direction, the eccentric amount is the same, the secondary mirror, the third mirror, the fourth mirror and the fifth mirror are eccentrically and obliquely arranged on the optical axis, and the eccentric amount and the oblique amount of each mirror are different.
The invention discloses a working method of a large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system, which comprises the following steps:
the light passing through the iris is incident on the reflecting surface of the main reflecting mirror, the first reflecting light is reflected by the reflecting surface of the main reflecting mirror, the first reflecting light is incident on the reflecting surface of the secondary reflecting mirror, the second reflecting light is reflected by the reflecting surface of the secondary reflecting mirror, the second reflecting light is incident on the reflecting surface of the third reflecting mirror, the third reflecting light is reflected by the reflecting surface of the third reflecting mirror, the third reflecting light is incident on the reflecting surface of the fourth reflecting mirror, the fourth reflecting light is reflected by the reflecting surface of the fourth reflecting mirror, the fourth reflecting light is incident on the reflecting surface of the fifth reflecting mirror, the fifth reflecting light is reflected by the reflecting surface of the fifth reflecting mirror, and the fifth reflecting light is received by the detector image surface and imaged. When the main reflector, 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 focus state with amplified resolution, and objects in the range of the view field are subjected to clear imaging with higher object space resolution.
The synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized. And re-imaging the primary intermediate image by using the rear relay imaging subsystem, and adding a field diaphragm at the stable primary intermediate image surface position to effectively eliminate stray light entering the rear relay imaging subsystem and the image surface of the detector. Through the arrangement, good imaging quality under different focal length states is ensured, a free-form surface is not required to be used, and processing and detecting costs are reduced.
The beneficial effects are that:
1. the invention discloses a large relative aperture off-axis five-reflection non-axial zooming imaging optical system, wherein a fourth reflecting mirror and a fifth reflecting mirror are fixed reflecting mirrors, a main reflecting mirror, a secondary reflecting mirror and a third reflecting mirror are movable reflecting mirrors, the main reflecting mirror, the secondary reflecting mirror and the third reflecting mirror form a full-type non-axial synchronous zooming initial imaging subsystem, and the fourth reflecting mirror and the fifth reflecting mirror form a rear relay imaging subsystem. And changing the focal power of the reflector group by non-axially moving the main reflector, the secondary reflector and the third reflector, so as to realize zooming. The rear relay imaging subsystem realizes the overturn, transmission and zoom imaging of an intermediate image plane through two fixed reflectors. By adding the view field diaphragm at the position of the primary intermediate image plane, stray light entering the rear relay imaging subsystem can be effectively eliminated. The synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized, so that good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.
2. The invention discloses a large relative aperture off-axis five-inverse non-axial zoom imaging optical system, wherein a non-axial movement vector is a non-axial movement vector synthesized by 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 three reflectors on an 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.
3. The invention discloses a large relative aperture off-axis five-inverse non-axial zoom imaging optical system, which establishes a correction method of high-order astigmatism and coma aberration of the zoom imaging optical system according to a Sedel aberration theory and a vector aberration theory, and utilizes the effect of eccentric amounts of three reflectors on aberration fields to actively balance wave aberration among multiple structures of the zoom imaging optical system so as to realize correction of the high-order astigmatism and the coma aberration of the non-axial zoom imaging optical system under different focal length structures.
4. According to the large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system disclosed by the invention, by arranging the view field diaphragm at the stable primary image surface, the stray light which cannot be eliminated due to the movement of the reflecting mirror in the non-axial synchronous zoom primary imaging subsystem can be greatly reduced, and the stray light which can reach the image surface of the detector can be effectively eliminated.
5. The large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system disclosed by the invention only needs to use a high-order aspheric reflector, does not need to use a free-form surface reflector, and reduces processing and detection costs.
Drawings
FIG. 1 is a schematic view of the structure of the device of the present invention.
Fig. 2 is a schematic diagram of a spatial coordinate system.
Fig. 3 is a short focal state light path diagram of the inventive apparatus.
Fig. 4 is a long focal state light path diagram of the device of the present invention.
Wherein, 01-iris, 02-primary mirror, 03-secondary mirror, 04-third mirror, 05-fourth mirror, 06-fifth mirror, 07-detector image plane.
Detailed Description
The invention will now be described in more detail with reference to the drawings, which illustrate preferred embodiments of the invention.
As shown in fig. 1, the main objective of the present invention is to provide a large relative aperture off-axis five-inverse non-axial zoom imaging optical system, which comprises an iris 01, a primary mirror 02, a secondary mirror 03, a third mirror 04, a fourth mirror 05, a fifth mirror 06, and a detector image surface 07.
The system is located in a spatial coordinate system (XYZ), with the coordinate axis directions shown in fig. 2.
The iris diaphragm 01 is an aperture diaphragm of the system, the aperture of the iris diaphragm varies along with the change of the focal length, and the relative aperture of the system is always 1:4.
The main reflector 02 is a concave reflector, and the surface of the main reflector is an 8-order aspheric surface, and is used for focusing and reflecting light rays from a target to form first reflected light.
The secondary reflector 03 is a convex reflector, and the surface is an 8-order aspheric surface, and is configured to reflect the light from the primary reflector 02 again to form a second reflected light.
The third reflecting mirror 04 is a concave reflecting mirror, and the surface of the third reflecting mirror is an 8-order aspheric surface, and is used for focusing the light from the secondary reflecting mirror 03 on the primary image surface to form third reflected light.
The fourth reflecting mirror 05 is a concave reflecting mirror, the surface is an 8-order aspheric surface, and the spatial position is unchanged, so that the light from the third reflecting mirror 04 is reflected to form four reflected lights.
The fifth reflecting mirror 06 is a concave reflecting mirror, the surface shape is an 8-order aspheric surface, and the spatial position is unchanged, so as to focus and image the light from the fourth reflecting mirror 05 on the target surface of the detector 07.
The primary mirror 02, the secondary mirror 03, and the third mirror 04 are moved to a predetermined position by a translation stage.
The main reflector 02, the secondary reflector 03 and the third reflector 04 form a full-type non-axial synchronous zooming initial imaging subsystem, and the fourth reflector 05 and the fifth reflector 06 form a relay imaging subsystem with the magnification of 1.
The relay imaging subsystem performs re-imaging on the primary image surface of the non-axial synchronous zooming primary imaging subsystem, and preferably, a field diaphragm can be arranged at the position of the primary image surface, so that stray light caused by the difficulty in arranging a light blocking device due to the movement of a reflecting mirror is greatly reduced, and the stray light which can reach the image surface of the detector is effectively eliminated.
The main reflector 02, the secondary reflector 03 and the third reflector 04 are elements of a variable-magnification group and a compensation group, and the change of the focal length of the system is realized by non-axial movement of the three reflectors, and the variable-magnification ratio is 5 times.
The primary intermediate image plane position of the non-axial synchronous zooming primary imaging subsystem is unchanged, so that the position of the detector image plane 07 is ensured to be unchanged.
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 an axial movement amount and a 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 three reflectors on an 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. The synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized, so that good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.
The non-axial movement of the main mirror 02, the sub-mirror 03 and the third mirror 04 is movement in one dimension in the YZ plane, which can be decomposed into an axial (Z direction) movement component and a vertical (Y direction) movement component, and specifically can be represented by different distances from the main mirror 02, the sub-mirror 03 and the third mirror 04 to the last surface and different Y axis eccentricities of the main mirror 02, the sub-mirror 03 and the third mirror 04 in different focal length states. Wherein, the change of the focal length of the system is realized by axial (Z direction) movement, the correction of higher-order astigmatism and coma aberration under different focal length structures of the system is realized by vertical axis (Y direction) movement, the synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized, so that good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.
The general expression for the 8 th order asphere is:
wherein z is a high surface vector, c is a surface curvature, k is a quadric surface coefficient, α i Is the coefficient of the i-th term in the polynomial.
The implementation method for actively balancing wave aberration between multiple structures of the zoom imaging optical system by utilizing the effect of the eccentric amounts of the three reflectors on the aberration field and the following optimization and determination method for the surface type parameters and the non-axial movement amounts of the reflectors are as follows:
in the present embodiment, the radii r of the reflecting surfaces of the primary reflecting mirror 02, the secondary reflecting mirror 03, the third reflecting mirror 04, the fourth reflecting mirror 05 and the fifth reflecting mirror 06 are the inverse of the curvature c, the quadric surface coefficient k, and the coefficients α i See table 1 for values of (c). It will be appreciated that the radius r, the quadric coefficient k, and the coefficients α i The values of (2) are not limited to those shown in Table 1, and can be adjusted according to actual needs by those skilled in the art.
Table 1 plane parameters of the primary mirror 02, secondary mirror 03, third mirror 04, fourth mirror 05 and fifth mirror 06
The spatial positions of the main mirror 02, the sub-mirror 03, and the third mirror 04 in the short-focal and long-focal states are shown in table 2. It will be appreciated that the distance between lenses and the value of the decentration of the lenses are not limited to those described in table 2, and those skilled in the art can adjust the distance according to actual needs.
Table 2 spatial position parameters of the primary mirror 02, the secondary mirror 03, and the third mirror 04
The main mirror 02, the sub-mirror 03, the third mirror 04, the fourth mirror 05, and the fifth mirror 06 may be made of aluminum alloy, beryllium aluminum alloy, silicon carbide, or other materials as a processing substrate. In order to increase the reflectivity of the main mirror 02, the sub-mirror 03, the third mirror 04, the fourth mirror 05, and the fifth mirror 06, a silver film or a gold film antireflection film may be coated on the respective reflection surfaces thereof.
The working light path of the large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system is as follows: the light passing through the iris 01 is incident on the reflecting surface of the main mirror 02, and is reflected by the reflecting surface of the main mirror 02 to form a first reflected light, the first reflected light is incident on the reflecting surface of the sub-mirror 03, and is reflected by the reflecting surface of the sub-mirror 03 to form a second reflected light, the second reflected light is incident on the reflecting surface of the third mirror 04, and is reflected by the reflecting surface of the third mirror 04 to form a third reflected light, the third reflected light is incident on the reflecting surface of the fourth mirror 05, and is reflected by the reflecting surface of the fourth mirror 05 to form a fourth reflected light, and the fourth reflected light is incident on the reflecting surface of the fifth mirror 06, and is reflected by the reflecting surface of the fifth mirror 06 to form a fifth reflected light, which is received by the detector image surface 07 and imaged. As shown in fig. 3, which is a schematic diagram of a short focal state of the system, when the main mirror 02, the secondary mirror 03 and the third mirror 04 are located at a designated position, the system can perform clear imaging on a larger field of view, and when the main mirror 02, the secondary mirror 03 and the third mirror 04 respectively move to the corresponding positions shown in fig. 4 in a non-axial direction, the system is switched to a 4.5-time amplified long focal state, so as to perform clear imaging on an object in a field of view with higher spatial resolution of an object.
The large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system provided by the embodiment of the invention has the following advantages:
1. the invention discloses a large relative aperture off-axis five-reflection non-axial zooming imaging optical system, wherein a fourth reflecting mirror and a fifth reflecting mirror are fixed reflecting mirrors, a main reflecting mirror, a secondary reflecting mirror and a third reflecting mirror are movable reflecting mirrors, the main reflecting mirror, the secondary reflecting mirror and the third reflecting mirror form a non-axial synchronous zooming initial imaging subsystem, and the fourth reflecting mirror and the fifth reflecting mirror form a rear relay imaging subsystem. And changing the focal power of the reflector group by non-axially moving the main reflector, the secondary reflector and the third reflector, so as to realize zooming. The rear relay imaging subsystem realizes the overturn, transmission and zoom imaging of an intermediate image plane through two fixed reflectors. By adding the view field diaphragm at the position of the primary intermediate image plane, stray light entering the rear relay imaging subsystem can be effectively eliminated. The synchronous adjustment of axial movement and vertical axis movement is realized through the non-axial movement vector, and the non-axial synchronous zooming of the zooming imaging optical system is realized, so that good imaging quality under different focal length states is ensured, and a free-form surface is not required to be used.
2. The invention discloses a large relative aperture off-axis five-reflection type non-axial zoom imaging optical system, wherein a non-axial movement vector is a non-axial movement vector synthesized by axial movement amount and vertical axis 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 three reflectors on an 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.
3. The invention discloses a large relative aperture off-axis five-reflection type non-axial zooming imaging optical system, which establishes a correcting method of high-order astigmatism and coma of the zooming imaging optical system according to a Sedel aberration theory and a vector aberration theory, and utilizes the effect of eccentric amounts of three reflectors on aberration fields to actively balance wave aberration among multiple structures of the zooming imaging optical system so as to realize the correction of the high-order astigmatism and the coma of the non-axial zooming imaging optical system under different focal length structures.
4. According to the large-relative-aperture off-axis five-reflection type non-axial zooming imaging optical system disclosed by the invention, by arranging the view field diaphragm at the stable primary image surface, the stray light which cannot be eliminated due to the movement of the reflecting mirror in the non-axial synchronous zooming primary imaging subsystem can be greatly reduced, and the stray light which can reach the image surface of the detector can be effectively eliminated.
5. The large-relative-aperture off-axis five-reflection type non-axial zooming imaging optical system disclosed by the invention only needs to use a high-order aspheric mirror, does not need to use a free-form surface reflecting mirror, and reduces processing and detection costs.
In summary, the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. An off-axis five-inverse non-axial zoom imaging optical system with large relative aperture is characterized in that: the detector comprises an iris diaphragm, 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 main reflector, the secondary reflector and the third reflector;
the iris diaphragm is an aperture diaphragm, and the aperture of the aperture diaphragm changes along with the change of the focal length; the relative aperture of the zooming imaging optical system is ensured to be fixed by adjusting the aperture of the aperture diaphragm;
the main reflector, the secondary reflector and the third reflector are elements for realizing zoom and compensation functions, and zoom imaging is realized by non-axially moving the main reflector, the secondary reflector and the third reflector; 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 effect of eccentric amounts of the main reflector, the secondary reflector and the third reflector on an 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 rear 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 obviously reduced, and therefore stray light which can reach the image surface of the detector is effectively eliminated.
2. A large relative aperture off-axis five-inverse 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, the magnification of the third reflector and the magnification of the fourth reflector meet the zoom relation with invariable conjugate distance, and the primary intermediate image plane position is invariable, so that the image plane position of the detector is invariable.
3. A large relative aperture off-axis five-inverse non-axial zoom imaging optical system as defined in claim 1, wherein: the main reflector, the third reflector, the fourth reflector and the fifth reflector are concave reflectors, the secondary reflector is a convex reflector, and the five reflectors are all 8-order aspheric surfaces; the reflecting surfaces of the primary and secondary mirrors are arranged in opposition, the reflecting surfaces of the secondary and third mirrors are arranged in opposition, the reflecting surfaces of the third and fourth mirrors are arranged in opposition, the reflecting surfaces of the fourth and fifth mirrors are arranged in opposition, and the fifth mirror and detector image surfaces are arranged in opposition; the iris diaphragm and the mirror surface center of the main mirror are eccentrically arranged along the Y-axis direction, the eccentric amount is the same, the secondary mirror, the third mirror, the fourth mirror and the fifth mirror are eccentrically and obliquely arranged on the optical axis, and the eccentric amount and the oblique amount of the secondary mirror, the third mirror, the fourth mirror and the fifth mirror are different.
4. A large relative aperture off-axis five-inverse non-axial zoom imaging optical system as defined in claim 1, 2 or 3, wherein: the working method is that,
the light passing through the iris diaphragm is incident on the reflecting surface of the main reflecting mirror, the first reflecting light is reflected by the reflecting surface of the main reflecting mirror, the first reflecting light is incident on the reflecting surface of the secondary reflecting mirror, the second reflecting light is reflected by the reflecting surface of the secondary reflecting mirror, the second reflecting light is incident on the reflecting surface of the third reflecting mirror, the third reflecting light is reflected by the reflecting surface of the third reflecting mirror, the third reflecting light is incident on the reflecting surface of the fourth reflecting mirror, the fourth reflecting light is reflected by the reflecting surface of the fourth reflecting mirror, the fourth reflecting light is incident on the reflecting surface of the fifth reflecting mirror, the fifth reflecting light is reflected by the reflecting surface of the fifth reflecting mirror, and the fifth reflecting light is received by the detector image surface and imaged; when the main reflector, 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 focus state with amplified resolution, 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 used for re-imaging the primary intermediate image, and stray light entering the rear relay imaging subsystem and the image surface of the detector is 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, a free-form surface is not required to be used, and processing and detecting costs are reduced.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210373899.6A CN114815200B (en) | 2022-04-11 | 2022-04-11 | Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210373899.6A CN114815200B (en) | 2022-04-11 | 2022-04-11 | Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114815200A CN114815200A (en) | 2022-07-29 |
| CN114815200B true CN114815200B (en) | 2023-08-15 |
Family
ID=82535608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210373899.6A Active CN114815200B (en) | 2022-04-11 | 2022-04-11 | Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114815200B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4804258A (en) * | 1986-05-05 | 1989-02-14 | Hughes Aircraft Company | Four mirror afocal wide field of view optical system |
| JP2003005073A (en) * | 2001-06-20 | 2003-01-08 | Nikon Corp | Off-axis reflection optical system |
| CN102981254A (en) * | 2012-12-27 | 2013-03-20 | 中国科学院长春光学精密机械与物理研究所 | Coaxial aspheric surface four-reflecting mirror optical system with long focal length short structure |
| CN103018890A (en) * | 2012-12-14 | 2013-04-03 | 中国科学院长春光学精密机械与物理研究所 | Optical system with four coaxial reflecting mirrors for 20-degree view field without central obscuration |
| CN104111520A (en) * | 2014-07-17 | 2014-10-22 | 中国科学院光电技术研究所 | Off-axis reflective imaging optical system |
| CN104977705A (en) * | 2015-04-01 | 2015-10-14 | 北京理工大学 | Large-visual-field off-axis reflection zooming optical system |
| CN110780432A (en) * | 2019-11-18 | 2020-02-11 | 中国科学院上海技术物理研究所 | Non-coaxial total reflection type active zooming relay optical system without moving element |
-
2022
- 2022-04-11 CN CN202210373899.6A patent/CN114815200B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4804258A (en) * | 1986-05-05 | 1989-02-14 | Hughes Aircraft Company | Four mirror afocal wide field of view optical system |
| JP2003005073A (en) * | 2001-06-20 | 2003-01-08 | Nikon Corp | Off-axis reflection optical system |
| CN103018890A (en) * | 2012-12-14 | 2013-04-03 | 中国科学院长春光学精密机械与物理研究所 | Optical system with four coaxial reflecting mirrors for 20-degree view field without central obscuration |
| CN102981254A (en) * | 2012-12-27 | 2013-03-20 | 中国科学院长春光学精密机械与物理研究所 | Coaxial aspheric surface four-reflecting mirror optical system with long focal length short structure |
| CN104111520A (en) * | 2014-07-17 | 2014-10-22 | 中国科学院光电技术研究所 | Off-axis reflective imaging optical system |
| CN104977705A (en) * | 2015-04-01 | 2015-10-14 | 北京理工大学 | Large-visual-field off-axis reflection zooming optical system |
| CN110780432A (en) * | 2019-11-18 | 2020-02-11 | 中国科学院上海技术物理研究所 | Non-coaxial total reflection type active zooming relay optical system without moving element |
Non-Patent Citations (1)
| Title |
|---|
| 新型离轴反射式变焦光学系统设计;闫佩佩等;《红外与激光工程》;20120625;第41卷(第06期);第1581-1586页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114815200A (en) | 2022-07-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114815199B (en) | Large-view-field off-axis five-reflection non-axial zooming imaging optical system | |
| CN110989152A (en) | Common-path flexible off-axis four-inverse focal length optical system | |
| CN110780432A (en) | Non-coaxial total reflection type active zooming relay optical system without moving element | |
| CN111624752A (en) | Compact type long-focus four-reflection telescopic optical system | |
| CN107643592A (en) | A kind of varifocal catadioptric optical system of long-focus | |
| CN114815202B (en) | Large-relative-aperture off-axis six-inverse non-axial zoom imaging optical system | |
| CN114815203B (en) | Off-axis four-reflection type non-axial zooming imaging optical system with large relative aperture | |
| CN112034605A (en) | Catadioptric Golay3 sparse aperture optical system | |
| CN103913840B (en) | Heavy caliber refraction-reflection type three constituent element continuous zooming optical system | |
| CN114047618B (en) | Off-axis afocal optical system of large-caliber spherical primary mirror | |
| CN111077664A (en) | Visible light-medium wave infrared integrated optical lens | |
| CN114815200B (en) | Large-relative-aperture off-axis five-inverse non-axial zoom imaging optical system | |
| CN211123452U (en) | Image pickup apparatus | |
| CN114815201B (en) | Off-axis reflection type regional variable resolution imaging optical system | |
| CN112612128B (en) | Medium-wave infrared refrigeration continuous zoom lens with large target surface and small F number and optical system | |
| CN113777779B (en) | Method for structure calculation and free-form surface type conversion of dual-focal-length deformation optical system | |
| CN210864179U (en) | Non-coaxial total reflection type active zooming relay optical system without moving element | |
| CN109212734B (en) | Free-form surface-based sparse aperture two-reflection optical imaging system | |
| CN113031238A (en) | Multi-mirror integrated large-view-field long-focus off-axis four-mirror optical system | |
| CN112882188A (en) | Image pickup apparatus | |
| CN115079406B (en) | Design method of catadioptric type fixed anti-telephoto zoom system | |
| CN111025613A (en) | Off-axis three-mirror imaging system based on free-form surface substrate phase element | |
| CN113640981B (en) | Large-caliber large-view-field double-concave-surface reflector telescope optical system | |
| US6487374B1 (en) | Viewfinder optical system | |
| CN217112865U (en) | Large-view-field off-axis four-mirror optical system based on free-form surface |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |