Dual-wavelength coaxial aiming system capable of realizing automatic collimation

Abstract

The invention provides a dual-wavelength coaxial aiming system capable of achieving automatic collimation. The dual-wavelength coaxial aiming system is used for inertial confinement nuclear fusion (ICF) picosecond terminal light path cone target posture adjustment and target spot positioning aiming. The system comprises an automatic collimation light path and an aiming light path with different working wavelengths, the automatic collimation light path comprises a light source, a beam splitter prism, a secondary mirror, a reflector and a CCD detector. The aiming light path consists of a primary mirror, a secondary mirror, a lens group, a beam splitter prism and a CCD (Charge Coupled Device) detector which are coaxial; according to the system, a secondary mirror is multiplexed, and automatic collimation and positioning aiming are achieved through transmission and reflection of different wavelengths; the flint and the crown glass are combined to correct color differences of different wavelengths; dual-wavelength light path image planes are at the same position; the system adopts a coaxial two-reflector structure, and is compact in structure and small in size.

Description

Technical Field

[0001] The invention belongs to the field of optical technology, and in particular relates to a dual-wavelength coaxial aiming system capable of realizing automatic alignment. Background Art

[0002] As a key way to achieve nuclear fusion, inertial confinement fusion (ICF) has significant scientific research significance and application value for promoting energy innovation, strengthening national defense and deepening research in the field of physics. ICF uses high-power lasers to uniformly irradiate a target pellet filled with thermonuclear materials, quickly compressing the target pellet to trigger rapid ignition. In this process, accurate target aiming and positioning are crucial, which directly determine the success rate of target shooting. Therefore, it is necessary to propose a cone-bottom aiming scheme that can not only adjust the attitude of the cone target, but also achieve accurate aiming of the target.

[0003] At present, the Chinese patent publication number is CN 101251643B, and the name is "Long focal length reflective microtelescope with angular resolution", which can realize automatic collimation and object point imaging. It mainly realizes the self-collimation function by multiplexing the primary reflector and the secondary reflector, but the central field of view is blocked, which will not only reduce the light throughput of the optical system, but also cause the resolution and contrast of the imaging to decrease. This limits the integrity of its field of view and the accuracy of observation to a certain extent, especially in the precision aiming scene that requires high-definition and unobstructed imaging, such as the cone target aiming in the ICF experiment, its performance may be affected. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a dual-wavelength coaxial aiming system that can realize automatic alignment, which is used for the posture adjustment and target positioning and aiming of the cone target by the picosecond terminal optical path of inertial confinement fusion (ICF) nuclear fusion.

[0005] To achieve the above objectives, this design is implemented through the following technical means:

[0006] A dual-wavelength coaxial aiming system capable of realizing automatic collimation realizes posture adjustment of a cone target and precise aiming of a target point by multiplexing a secondary mirror. The system comprises: an automatic collimation optical path and an aiming optical path of different working wavelengths; the automatic collimation optical path comprises a light source, a beam splitter prism, a secondary mirror, a reflector and a CCD detector; the aiming optical path is composed of a primary mirror, a secondary mirror, a lens group, a beam splitter prism and a CCD detector, and each optical element is coaxial; the system reuses the secondary mirror, and realizes automatic collimation and positioning aiming by transmission and reflection of different wavelengths respectively; a combination of flint and crown glass is used to correct chromatic aberration of different wavelengths; the image plane of the dual-wavelength optical path is in the same position; a coaxial two-reflection structure is adopted, which is compact and small in size.

[0007] The primary mirror is used to receive and reflect light emitted from the object surface;

[0008] The secondary mirror has a front and rear surface that has high transmission for the working wavelength of the autocollimation system, and a rear surface that has high reflection for the working wavelength of the aiming optical path system;

[0009] The lens group is used to receive light transmitted or reflected by the secondary mirror;

[0010] The light sources are LEDs in the visible light band and main lasers in the near infrared band.

[0011] Furthermore, the secondary mirror is an aspherical surface with a conic coefficient.

[0012] Furthermore, the aspheric surface equation satisfies the following equation:

[0013]

[0014] Among them, z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the cone coefficient.

[0015] Furthermore, the lens group consists of a doublet lens and a single lens, and the doublet lens adopts two kinds of glass materials, crown and flint respectively.

[0016] Furthermore, the primary mirror and the lens group are both spherical mirrors;

[0017] Furthermore, the beam splitting surface of the beam splitting prism is semi-transparent and semi-reflective to the working wavelength of the self-collimation system, and highly transmissive to the working wavelength of the aiming optical path system.

[0018] Compared with the prior art, the present invention realizes the self-collimation function through the secondary mirror transmission, and the central field of view is unobstructed. The above technical solution conceived by the present invention has the following beneficial effects:

[0019] (1) By multiplexing the secondary mirror with high transmittance and high reflection for different working wavelengths, the attitude adjustment of the cone target and the precise aiming of the target point can be achieved; at different working wavelengths, the automatic collimation optical path and the aiming optical path can achieve high resolution requirements;

[0020] (2) Taking into account the dual-wavelength band width, the chromatic aberration between different wavelengths is corrected by using a lens group composed of flint and crown glass;

[0021] (3) The coaxial two-mirror structure is adopted to effectively utilize the system space, shorten the system length, and make the entire optical system compact and small in size. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a principle diagram of the aiming optical path of a dual-wavelength coaxial aiming system capable of realizing automatic collimation according to the present invention;

[0023] Figure 2It is a principle diagram of an automatic collimation optical path of a dual-wavelength coaxial aiming system capable of realizing automatic collimation according to the present invention;

[0024] Figure 3 is a schematic diagram of a modulation transfer function of an embodiment of the present invention when the working wavelength is 1053nm±5nm;

[0025] Figure 4 is a schematic diagram of a modulation transfer function of an embodiment of the present invention when the working wavelength is 525nm±5nm;

[0026] Figure 5 is a point diagram of an embodiment of the present invention with an operating wavelength of 1053 nm ± 5 nm;

[0027] Figure 6 is a point diagram of an embodiment of the present invention with an operating wavelength of 525 nm ± 5 nm;

[0028] In the figure: 1. Primary mirror; 2. Secondary mirror; 3. Lens group; 4. Beam splitter prism; 5. Reflector; 6. CCD detector; 7. Light source. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation modes, but this should not limit the protection scope of the present invention.

[0030] In the inertial confinement fusion (ICF) picosecond terminal system, the cone target posture adjustment and target positioning and aiming are crucial links. To achieve this goal, this embodiment provides a dual-wavelength coaxial aiming system that can realize automatic collimation, combining automatic collimation optical paths and aiming optical paths with different working wavelengths to ensure accurate adjustment and aiming of the cone target in the ICF experiment.

[0031] A dual-wavelength coaxial aiming system capable of realizing automatic alignment comprises an automatic alignment optical path and an aiming optical path with different working wavelengths.

[0032] Automatically collimating the optical path, such as Figure 2 As shown in the figure, it includes a light source 7, a beam splitter prism 4, a secondary mirror 2, a reflector 5 and a CCD detector 6; the light beam diverged by the light source 7 is reflected by the beam splitter prism 4, and then emitted as parallel light through the lens group 3 and the secondary mirror 2. The parallel light is then reflected by the reflector 5, and again passes through the secondary mirror 2, the lens group 3 and the beam splitter prism 4, and finally focuses on the CCD detector 6, thus realizing automatic collimation.

[0033] The dual-wavelength coaxial aiming system designed by the present invention for realizing automatic alignment has higher imaging resolution under two working wavelengths.

[0034] Aiming light path Figure 1As shown: it includes a primary mirror 1, a secondary mirror 2, a lens group 3, a beam splitter prism 4, and a CCD detector 6. The optical elements are coaxial. The light emitted by the object point (such as a specific point on the cone target) is reflected by the primary mirror 1 and the secondary mirror 2 in sequence, and then passes through the lens group 3 and the beam splitter prism 4, and finally forms an image on the CCD detector 6, thereby realizing precise positioning and aiming of the target.

[0035] The primary mirror 1 is concave in shape and adopts a spherical mirror design, which can effectively reduce the manufacturing difficulty and manufacturing cost, and is used to receive and reflect the light emitted by the object surface;

[0036] The secondary mirror 2 uses a conic surface to correct spherical aberration, and its aspheric equation is:

[0037]

[0038] Among them, z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the cone coefficient;

[0039] Lens group 3 is composed of a double cemented lens and a single lens, using two glass materials, crown and flint respectively. The chromatic aberration introduced by these two materials is opposite in positive and negative, and can correct the chromatic aberration introduced by dual wavelengths;

[0040] The beam splitting surface of the beam splitting prism 4 is semi-reflective and semi-transmissive for the working wavelength of the automatic collimation optical path, and highly transmissive for the working wavelength of the aiming optical path, so as to ensure the correct separation and transmission of the two different working wavelengths.

[0041] The specific indicators are shown in Table 1.

[0042] Table 1

[0043]

[0044] The surface parameters of each component are shown in Table 2.

[0045] Table 2

[0046]

[0047]

[0048] The imaging performance of the dual-wavelength coaxial aiming system designed above is analyzed, mainly including the modulation transfer function and spot diagram of the aiming optical path and the automatic collimation optical path. Figure 3 , Figure 4 , Figure 5 and Figure 6 shown.

[0049] Imaging performance of aiming optical path: the working wavelength is 1053nm±5nm, the modulation transfer function curves of each field of view are close to the diffraction limit, the MTF at the cutoff frequency of 90lp / mm is greater than 0.2, the object space resolution can reach 11.11μm, the point diagrams of each field of view are within the Airy disk, the imaging quality is close to the diffraction limit, and the system has excellent focusing performance.

[0050] Collimated optical path imaging performance: When the operating wavelength is 590nm±5nm in the visible light band, the modulation transfer function curve is close to the diffraction limit, the RMS radius is smaller than the Airy disk radius, and the angular resolution is about 6", which means that the system can accurately distinguish tiny angular changes.

[0051] In summary, the dual-wavelength coaxial aiming system designed above can realize automatic collimation. In the embodiment, at the working wavelengths of 525nm±5nm and 1053nm±5nm, both the automatic collimation optical path and the aiming optical path can achieve high resolution requirements and show excellent imaging performance. The aiming optical path has high-precision imaging capability and imaging quality close to the diffraction limit, which is suitable for high-precision aiming tasks in ICF experiments. The automatic collimation optical path has good angular resolution function and is suitable for optical measurement and calibration tasks.

Claims

1. A dual-wavelength coaxial aiming system capable of realizing automatic alignment, used for cone target attitude adjustment and target point positioning and aiming of inertial confinement nuclear fusion picosecond terminal system, characterized in that: It includes automatic collimation optical path and aiming optical path of different working wavelengths; among which, The automatic collimation optical path comprises a reflector, a secondary mirror, a lens group, a beam splitter, a CCD detector and a light source; the divergent light beam from the light source is reflected by the beam splitter, then passes through the lens group and the secondary mirror to form parallel light emission, and then is reflected by the reflector, sequentially passes through the secondary mirror, the lens group and the beam splitter to be focused on the CCD detector; The aiming optical path includes a primary mirror, a secondary mirror, a lens group, a beam splitter prism and a CCD detector placed on the same optical axis. The light emitted by the object point is reflected by the primary mirror and the secondary mirror in sequence, and then imaged on the CCD detector through the lens group and the beam splitter prism. The secondary mirror has high transmittance to the working wavelength of the automatic collimation light path, and high reflectance to the working wavelength of the aiming light path; the lens group is used to receive the light transmitted or reflected by the secondary mirror, and to correct the chromatic aberration caused by different wavelengths; the splitting surface of the splitting prism is semi-reflective and semi-transparent to the working wavelength of the automatic collimation light path, and has high transmittance to the working wavelength of the aiming light path.

2. A dual-wavelength coaxial aiming system capable of realizing automatic alignment according to claim 1, characterized in that: The primary mirror is a concave spherical mirror, which is used to receive and reflect light emitted from the object surface.

3. A dual-wavelength coaxial aiming system capable of realizing automatic alignment according to claim 1, characterized in that: The secondary mirror is an aspherical lens with a conic coefficient, and its aspherical equation is: Among them, z(r, θ) is the sagittal height of the optical surface, r is the radius of the meridian section circle, θ is the direction angle, c is the curvature, and k is the cone coefficient.

4. The dual-wavelength coaxial aiming system capable of realizing automatic alignment according to claim 1, characterized in that: The lens group consists of a doublet lens and a singlet lens, wherein the doublet lens adopts crown glass and flint glass materials respectively to correct the chromatic aberration introduced by dual wavelengths.

5. The dual-wavelength coaxial aiming system capable of realizing automatic alignment according to claim 1, characterized in that: The light sources are LEDs in the visible light band and main lasers in the near infrared band.

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