Coaxial three-mirror wide-spectrum telescopic optical system configuration

Abstract

The invention provides a coaxial three-mirror wide-spectrum telescopic optical system configuration, which belongs to the technical field of optical systems and specifically comprises a pupil-deflection primary mirror, a pupil-deflection secondary mirror, a first reflex plane mirror, a pupil-deflection third mirror and a second reflex plane mirror. The partial pupil primary mirror, the partial pupil secondary mirror and the first turning plane mirror form a wide spectrum reflection type objective lens group; the partial pupil third mirror and the second turning plane mirror form a wide-spectrum reflective eyepiece group; the first turning plane reflecting mirror, the partial pupil third mirror and the second turning plane reflecting mirror are positioned on one side, back to the partial pupil secondary mirror, of the partial pupil primary mirror; a light path of the coaxial three-mirror wide-spectrum telescopic optical system sequentially passes through the pupil deflection primary mirror, the pupil deflection secondary mirror, the first turning plane mirror, the pupil deflection third mirror and the second turning plane mirror according to the optical axis. The coaxial three-mirror wide-spectrum telescopic optical system configuration is realized, and the coaxial three-mirror wide-spectrum telescopic optical system has the advantages of high magnification, unobstructed light path, wide spectrum, high-quality imaging and compact spatial layout.

Description

Technical Field

[0001] The present application relates to the field of optical systems, and in particular to a coaxial three-mirror wide-spectrum telescopic optical system configuration. Background Art

[0002] Depending on the distance of the target to be observed, the optoelectronic observation and monitoring system usually requires the optical system to have multiple focal lengths, which are used for the detection, identification, recognition and large-scale monitoring of targets at different distances. At the same time, since the target characteristics of targets in different spectral bands are different, in order to improve the detection and recognition probability of targets, the optical system needs to work in different spectral bands at the same time. However, the types of wide-band transmission optical materials are limited, and large-aperture optical materials are difficult to prepare and process. Therefore, wide-band optical systems generally adopt a reflective optical system configuration. The reflector does not introduce chromatic aberration, which is particularly beneficial to the design of wide-band optical systems. At the same time, the base material and aperture of the reflector are not restricted, and the processing is relatively easy to achieve.

[0003] Commonly used reflective telescope optical system configurations can be divided into coaxial reflective telescope optical system configurations and off-axis reflective telescope optical system configurations. The advantage of the coaxial reflective telescope optical system configuration is that it has a high telephoto magnification, but the disadvantage is that there is a center obstruction problem, which causes a decrease in the energy utilization of the optical system and a mid-frequency loss in the optical transfer function. The off-axis reflective telescope optical system configuration solves the center obstruction problem by using an off-axis method and improves the energy utilization. However, the disadvantage of the off-axis reflective telescope optical system configuration is that the telephoto magnification is low, generally less than 6. × , it is difficult to meet the needs of the system. At present, there is no effective solution that has both high telephoto magnification and unobstructed optical system. Summary of the invention

[0004] In view of this, the present application provides a coaxial three-mirror wide-spectrum telescopic optical system configuration, which solves the problem that the existing coaxial reflective telescopic optical system has a high telescopic magnification but has central obstruction, and the off-axis three-mirror telescopic optical system has no obstruction but low telescopic magnification, and the two cannot be taken into account at the same time. The coaxial three-mirror wide-spectrum telescopic optical system configuration is realized, which has the advantages of high magnification, unobstructed optical path, wide spectrum, high-quality imaging, and compact spatial layout.

[0005] The present application provides a coaxial three-mirror wide spectrum telescopic optical system configuration adopts the following technical solution:

[0006] A coaxial three-mirror wide-spectrum telescopic optical system configuration includes a deflected pupil primary mirror, a deflected pupil secondary mirror, a first folding plane reflector, a deflected pupil third mirror, and a second folding plane reflector;

[0007] The pupil-deflecting primary mirror, the pupil-deflecting secondary mirror and the first folding plane reflector constitute a wide-spectrum reflective objective lens group; the pupil-deflecting third mirror and the second folding plane reflector constitute a wide-spectrum reflective eyepiece group;

[0008] The first folding plane reflection, the deflection pupil three mirrors and the second folding plane reflection mirror are located on the side of the deflection pupil primary mirror facing away from the deflection pupil secondary mirror;

[0009] The optical path of the coaxial three-mirror wide-spectrum telescope optical system passes through the deflected pupil primary mirror, the deflected pupil secondary mirror, the first folding plane reflector, the deflected pupil third mirror and the second folding plane reflector in sequence according to the optical axis.

[0010] Optionally, the wide-spectrum reflective objective lens group and the wide-spectrum reflective eyepiece group constitute a Kepler-type telescopic optical system with an intermediate real focus.

[0011] Optionally, the light-receiving surface of the deflected pupil primary mirror is a parabola, the light-receiving surface of the deflected pupil secondary mirror is a hyperbolic surface, and the light-receiving surface of the deflected pupil tertiary mirror is a high-order aspherical surface.

[0012] Optionally, the manufacturing materials of the deflected pupil primary mirror, the deflected pupil secondary mirror, and the deflected pupil tertiary mirror are microcrystalline glass, fused quartz or silicon carbide.

[0013] Optionally, the first folding plane reflector and the second folding plane reflector are made of fused quartz or K9 optical glass material.

[0014] Optional, wide spectrum telescope optical system configuration with focal length range of 1000mm~1400mm and magnification of 10 × , the optical system F number is f / 4 ~ f / 6.

[0015] Optionally, the detectors applicable to the wide spectrum telescopic optical system configuration are 1920×1080 visible light focal plane detectors, 640×512 short wave detectors, and 640×512 cooled medium wave infrared focal plane detectors;

[0016] Among them, the spectral range of the 1920×1080 visible light focal plane detector is visible light, with a wavelength of 0.4μm to 0.7μm; the spectral range of the 640×512 short-wave detector is short-wave, with a wavelength of 0.9μm to 1.7μm; the spectral range of the 640×512 cooled medium-wave infrared focal plane detector is medium-wave infrared, with a wavelength of 3μm to 5μm.

[0017] In summary, this application includes the following beneficial technical effects:

[0018] The center obstruction problem of the coaxial reflective optical system configuration is solved by adopting an optical system configuration of pupil offset and multi-mirror folded light path.

[0019] Due to the pupil offset design method, the optical system is also a coaxial optical system, without introducing off-axis aberrations, achieving a high telephoto magnification and overcoming the problem of low magnification of conventional off-axis three-mirror telephoto optical systems.

[0020] Both the telescope objective lens group and the telescope eyepiece group are reflective, the system has no chromatic aberration, and achieves wide spectrum high-quality imaging.

[0021] Optical surfaces such as quadratic surfaces and high-order aspheric surfaces are used to balance the aberrations of the optical system and achieve excellent image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic diagram of the optical path of the coaxial three-mirror wide-spectrum telescope optical system configuration of the present application.

[0024] Figure 2 This is a diagram of the visible light optical transfer function of the coaxial three-mirror wide spectrum telescope optical system of this application;

[0025] Figure 3 This is the short-wave optical transfer function diagram of the coaxial three-mirror wide-spectrum telescope optical system of this application;

[0026] Figure 4 This is a diagram of the mid-wave infrared optical transfer function in the coaxial three-mirror wide-spectrum telescope optical system of this application.

[0027] Explanation of the accompanying drawings: 1. Deflected pupil primary mirror; 2. Deflected pupil secondary mirror; 3. First folding plane reflector; 4. Deflected pupil third mirror; 5. Second folding plane reflector. DETAILED DESCRIPTION

[0028] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0029] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0030] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0031] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0032] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0033] The embodiment of the present application provides a coaxial three-mirror wide-spectrum telescopic optical system configuration.

[0034] like Figures 1 to 4 As shown, a coaxial three-mirror wide-spectrum telescopic optical system configuration includes a deflected pupil primary mirror 1, a deflected pupil secondary mirror 2, a first folding plane reflector 3, a deflected pupil third mirror 4 and a second folding plane reflector 5.

[0035] The pupil-deflecting primary mirror 1, the pupil-deflecting secondary mirror 2 and the first folding plane reflector 3 constitute a wide-spectrum reflective objective lens group; the pupil-deflecting tertiary mirror 4 and the second folding plane reflector 5 constitute a wide-spectrum reflective eyepiece group.

[0036] The first folding plane reflection, pupil deflection three mirrors 4 and the second folding plane reflection mirror 5 are located on the side of the pupil deflection primary mirror 1 facing away from the pupil deflection secondary mirror 2 .

[0037] The optical path of the coaxial three-mirror wide-spectrum telescope optical system passes through the deflected pupil primary mirror 1, the deflected pupil secondary mirror 2, the first folding plane reflector 3, the deflected pupil third mirror 4 and the second folding plane reflector 5 in sequence according to the optical axis.

[0038] The wide-spectrum reflective objective lens group and the wide-spectrum reflective eyepiece group constitute a Kepler type telescopic optical system with an intermediate real focus.

[0039] In the present application, the optical path is formed by the primary mirror 1, the secondary mirror 2, the first folding plane reflector 3, the third mirror 4, and the second folding plane reflector 5 along the optical axis to form the optical path of the coaxial three-mirror wide-spectrum telescope optical system. The optical system configuration is based on the principle of reflective optical system and the aberration balance theory, and adopts the design method of pupil offset and multi-mirror folded optical path, which achieves high telescope magnification, high-quality imaging, and compact spatial layout while achieving unobstructed wide-spectrum light beam.

[0040] The wide spectrum telescope optical system has a focal length range of 1000mm to 1400mm and a magnification of 10 × , the optical system F number is f / 4 ~ f / 6.

[0041] The detectors suitable for the wide-spectrum telescope optical system configuration are a 1920×1080 visible light focal plane detector, a 640×512 short-wave detector and a 640×512 cooled medium-wave infrared focal plane detector; among them, the spectral range of the 1920×1080 visible light focal plane detector is visible light, with a wavelength of 0.4μm to 0.7μm; the spectral range of the 640×512 short-wave detector is short-wave, with a wavelength of 0.9μm to 1.7μm; the spectral range of the 640×512 cooled medium-wave infrared focal plane detector is medium-wave infrared, with a wavelength of 3μm to 5μm.

[0042] The light receiving surface of the deflected pupil primary mirror 1 is a parabola, the light receiving surface of the deflected pupil secondary mirror 2 is a hyperbolic surface, and the light receiving surface of the deflected pupil tertiary mirror 4 is a high-order aspherical surface.

[0043] The materials used to manufacture the deflected pupil primary mirror 1 , the deflected pupil secondary mirror 2 , and the deflected pupil tertiary mirror 4 are microcrystalline glass, fused quartz, or silicon carbide.

[0044] The first folding plane reflector 3 and the second folding plane reflector 5 are made of fused quartz or K9 optical glass.

[0045] The embodiment of the present application discloses optical parameters of the optical path of a coaxial three-mirror wide-spectrum telescope optical system, as shown in Table 1.

[0046] Table 1 Optical parameters of the optical path of the improved coaxial three-mirror wide-spectrum telescope optical system (unit: mm)

[0047]

[0048] The embodiments of the present application also disclose the aspheric coefficients of the deflected pupil primary mirror, the deflected pupil secondary mirror and the deflected pupil triple mirror, as shown in Table 2.

[0049] Table 2 Aspheric coefficient table

[0050] K A B C D Deviated pupil primary mirror -1 —— —— —— —— Deviated pupil lens -2.12 Three-lens mirror 0 -1.5587E-8 4.3852E-12 -2.5750E-15 5.587E-19

[0051] The aspheric equation is:

[0052] Where: r is the distance from the optical axis; R is the radius of curvature at the vertex of the aspheric surface; k is the quadratic curve constant; A, B, C, and D are all aspheric coefficients.

[0053] The embodiment of the present application also discloses the eccentricity and tilt of the first folding plane reflector, the second folding plane reflector and the exit pupil, as shown in Table 3.

[0054] Table 3 Eccentricity and inclination parameter table

[0055] Eccentricity in Y direction / mm Tilt in α direction / ° First folding plane reflector 0 63.27 Second folding plane reflector 0 26.73 Exit pupil 22.35 0

[0056] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A coaxial three-mirror wide spectrum telescope optical system configuration, characterized in that: It comprises a deflected pupil primary mirror (1), a deflected pupil secondary mirror (2), a first folding plane reflecting mirror (3), a deflected pupil tertiary mirror (4) and a second folding plane reflecting mirror (5); The pupil-deflecting primary mirror (1), the pupil-deflecting secondary mirror (2) and the first folding plane reflecting mirror (3) constitute a wide-spectrum reflective objective lens group; the pupil-deflecting tertiary mirror (4) and the second folding plane reflecting mirror (5) constitute a wide-spectrum reflective eyepiece group; The first folding plane reflection, pupil deflection three-mirror (4) and the second folding plane reflection mirror (5) are located on a side of the pupil deflection primary mirror (1) facing away from the pupil deflection secondary mirror (2); The optical path of the coaxial three-mirror wide-spectrum telescopic optical system passes through a deflected pupil primary mirror (1), a deflected pupil secondary mirror (2), a first folding plane reflecting mirror (3), a deflected pupil third mirror (4) and a second folding plane reflecting mirror (5) in sequence along the optical axis.

2. The coaxial three-mirror wide spectrum telescope optical system configuration according to claim 1 is characterized in that: The wide-spectrum reflective objective lens group and the wide-spectrum reflective eyepiece group constitute a Kepler type telescopic optical system with an intermediate real focus.

3. The coaxial three-mirror wide spectrum telescopic optical system configuration according to claim 1 is characterized in that: The light receiving surface of the deflected pupil primary mirror (1) is a parabola, the light receiving surface of the deflected pupil secondary mirror (2) is a hyperbolic surface, and the light receiving surface of the deflected pupil tertiary mirror (4) is a high-order aspherical surface.

4. The coaxial three-mirror wide spectrum telescope optical system configuration according to claim 1 is characterized in that: The materials used to manufacture the deflected pupil primary mirror (1), the deflected pupil secondary mirror (2), and the deflected pupil tertiary mirror (4) are microcrystalline glass, fused quartz, or silicon carbide.

5. The coaxial three-mirror wide spectrum telescopic optical system configuration according to claim 1 is characterized in that: The first folding plane reflector (3) and the second folding plane reflector (5) are made of fused quartz or K9 optical glass material.

6. The coaxial three-mirror wide spectrum telescopic optical system configuration according to claim 1 is characterized in that: The wide spectrum telescope optical system has a focal length range of 1000mm to 1400mm and a magnification of 10 × , the optical system F number is f / 4 ~ f / 6.

7. The coaxial three-mirror wide spectrum telescopic optical system configuration according to claim 1 is characterized in that: The detectors applicable to the wide spectrum telescope optical system configuration are 1920×1080 visible light focal plane detector, 640×512 short wave detector and 640×512 cooled medium wave infrared focal plane detector; Among them, the spectral range of the 1920×1080 visible light focal plane detector is visible light, with a wavelength of 0.4μm to 0.7μm; the spectral range of the 640×512 short-wave detector is short-wave, with a wavelength of 0.9μm to 1.7μm; the spectral range of the 640×512 cooled medium-wave infrared focal plane detector is medium-wave infrared, with a wavelength of 3μm to 5μm.

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