Modular-design catadioptric auto-collimation angle measurement optical system
Through modular design and a refraction self-collimating angle measurement optical system with delayed focus, the problem of improving structure reusability and imaging effect in the existing technology is solved, and high accuracy of monitoring of small angle changes in the space field is achieved. and efficient monitoring reduces system costs.
Patent Information
- Application Number
- CN202410921525.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-10
- Publication Date
- 2024-12-10
AI Technical Summary
The existing refraction reflective self-collimating angle measurement optical system is difficult to achieve secondary optimization of structural reusability and imaging effects in the space field, resulting in high engineering cost, high equipment production difficulty, and excessive cost of monitoring systems for other tasks. .
The modular design of the folding reflective self-collective angle measurement optical system is adopted. Through structural segmentation and delayed focus design ideas, the replacement correction mirror group is used to meet the monitoring needs of different angle changes, and the correction mirror group is optimized to improve monitoring accuracy and Imaging effect.
On the basis of ensuring the accuracy of angle monitoring, the structural reusability and imaging effect of the system are improved. By replacing the correction mirror group, different monitoring needs are met, the imaging spot radius is significantly reduced, the aberration impact is eliminated, and the monitoring accuracy is improved.
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Figure CN119104024A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of optical system design, in particular to a modularly designed catadioptric self-collimating angle measuring optical system. Background Art
[0002] The optical angle measurement system based on the principle of self-collimation is often used in the deformation monitoring of key structures in the space field because of its non-contact, high precision and strong anti-interference ability. The catadioptric structure adds refractive optical components based on the characteristics of the reflective collimation system. It can simultaneously correct the system's off-axis aberration and spherical aberration, and can also increase the system's field of view. However, due to the presence of transmissive optical elements, it is difficult to achieve a lightweight and large-aperture design. The reflective Cassegrain optical system has the advantages of eliminating chromatic aberration, compact structure, and great design freedom, and is widely used in space observation, satellite communications, and precision monitoring.
[0003] Existing technologies can already meet the needs of most on-orbit monitoring tasks. In 2020, Ma Zixuan designed a global compact reentrant detection optical system based on the Maksutov telescope. The structure has good detection performance and can be used for accurate detection of targets. In 2023, Li Yuexin proposed a high-orbit remote sensing satellite optical axis pointing error angle measurement system. This structure is based on a card structure and adopts a refractive-reflective structure to provide technical support for the normal and accurate operation of remote sensing satellites in a space environment. In 2023, Dong Shuairen (CN117848317A) of the Shanghai Institute of Space Control Technology invented and disclosed a star sensor, a monitoring device and a monitoring method for changes in the reference light vector based on a star sensor, which can monitor changes caused by orbital forces or thermal deformation. The on-orbit measurement and calibration of the reference light vector change can improve the correlation reference accuracy between the star sensitivity and the attitude measurement system in which it is located, thereby improving the ground positioning accuracy of the satellite. However, the engineering cost of this type of system is high and the equipment manufacturing is difficult. The equipment that has already left the factory cannot be optimized and improved. There is a large room for improvement in versatility. For other tasks that require similar general structures but different component detail parameters, the cost of recreating the monitoring system is too high. Therefore, how to improve the structural reusability of this type of system and perform secondary optimization of the imaging effect is a problem that needs to be solved urgently. The present invention establishes a modularly designed refractive-reflective self-collimating angle-measuring optical system, proposes a delayed focusing design concept based on structural segmentation, and analyzes the influence of different corrective lens groups on the final imaging performance. Summary of the invention
[0004] In view of the shortcomings of the prior art, the present invention provides a modularly designed catadioptric self-collimating angle measuring optical system, aiming to solve the problem of monitoring small angle changes in the space field by providing a modularly designed catadioptric self-collimating angle measuring optical system, and to design an optical monitoring structure with structural advantages on the basis of ensuring the angle monitoring accuracy requirements.
[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a modularly designed catadioptric self-collimating angle measuring optical system, including a system light source, a corrective lens group, a beam splitter, a primary and secondary reflectors, and a photoelectric detector. The system light source emits light that is incident on the corrective lens group. The corrective lens group is used to collimate the light beam. The parallel light after passing through the corrective lens group is reflected by the beam splitter. The light beam passes through the light hole of the primary reflector and hits the secondary reflector. After reflection by the secondary reflector, it is diverged to the reflective mirror surface of the primary reflector and then emitted as parallel light to the target reflector.
[0006] Preferably, the system light source is an LED point light source, a laser point light source or other light sources that meet the detection intensity requirements. Under appropriate distance requirements, the light emitted by the light source can be used as monitoring light after entering the system.
[0007] Preferably, the light beam of the correction lens group is transformed from divergent light to parallel light after passing through the correction lens group, so as to collimate and eliminate aberrations of the incident light, and is a single lens, a double cemented lens or a combination of the two lenses.
[0008] Preferably, the beam splitter performs a 50:50 beam splitting effect on parallel light, and the incident light is reflected by the beam splitter to reflect a part of the light beam to the next part of the system structure. The beam splitter can be a plane beam splitter or a three-dimensional beam splitter.
[0009] Preferably, the parallel light from the primary and secondary reflectors passes through the beam splitter and then hits the secondary reflector through the light hole between the primary mirror, and is then reflected by the secondary reflector onto the surface of the primary reflector. The focusing effect of the primary reflector emits parallel light for detection. The surface types of the primary and secondary reflectors can be spherical mirrors or aspherical mirrors as long as the beam expansion function is met.
[0010] Preferably, the photoelectric detector receives the light beam transmitted through the beam splitter and carrying the deflection information of the target reflector, extracts and resolves the formed light spot information, and uses a CCD, CMOS, PSD or QD detector.
[0011] Preferably, the effect of the corrective lens assembly on the light beam includes the following specific parts:
[0012] The corrective lens group of the light source part is exactly the same as the corrective lens group of the detector part. The corrective lens group of the light source part plays a collimating role on the light beam, while the corrective lens group of the detector part plays a focusing role on the light beam.
[0013] Preferably, the material involved in the corrective lens assembly is glass material.
[0014] Preferably, the beam expansion effect involved in the primary and secondary reflectors is that the primary and secondary reflectors are structured as an afocal system, which may be an improved Cassegrain structure, a Galilean beam expansion structure or a reflective beam expansion structure.
[0015] Preferably, the detection dimension involved by the photoelectric detector is a linear array detector or a planar array detector according to the deflection of the target reflector.
[0016] The present invention provides a modularly designed catadioptric self-collimating angle measuring optical system, which has the following beneficial effects:
[0017] 1. In the present invention, the light passing through the primary mirror and the secondary mirror structure is parallel light. After that, the light emitted by the light source is parallel output light after passing through the correction lens group, which is reflected by the secondary mirror to the mirror surface of the primary mirror. When the reflected light of the target reflector hits the beam splitter through the original path, due to the reflection effect of the beam splitter, the lens group between the electrical detector and the beam splitter, which is exactly the same as the correction lens group on the light source path, converges on the photoelectric detector to form an image. By changing or replacing the correction lens group, different on-orbit angle change monitoring needs can be met.
[0018] 2. The present invention sets three corrective lens groups. When different types of corrective lens groups are used for monitoring imaging, different imaging effects will be achieved. When a combined lens group is used as a corrective lens group, the radius of the light spot is significantly reduced, and the effect of eliminating the influence of aberration is obvious. By optimizing the corrective lens group, the effect of improving monitoring accuracy can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A schematic diagram of a modularly designed catadioptric self-collimating angle measuring optical system of the present invention;
[0020] Figure 2 A schematic diagram of different corrective lens groups of a modularly designed catadioptric self-collimating angle-measuring optical system of the present invention;
[0021] Figure 3 Comparison of imaging effects when using different corrective lens groups for the modularly designed catadioptric self-collimating angle-measuring optical system of the present invention.
[0022] Among them, 1. System light source; 2. Correction lens group; 3. Beam splitter; 4. Primary and secondary reflectors; 5. Photodetector. DETAILED DESCRIPTION
[0023] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0024] Please see attached Figure 1 -Attached Figure 3The embodiment of the present invention provides a modularly designed catadioptric self-collimating angle measuring optical system, comprising a system light source 1, a corrective lens group 2, a beam splitter 3, a primary and secondary reflectors 4, and a photoelectric detector 5, characterized in that the system light source 1 emits light incident on the corrective lens group 2, the corrective lens group 2 is used to collimate the light beam, the parallel light after passing through the corrective lens group 2 is reflected by the beam splitter 3, the light beam passes through the light hole of the primary reflector and hits the secondary reflector, and is reflected by the secondary reflector and diverges to the reflective mirror surface of the primary reflector, and is emitted again as parallel light to the target reflector.
[0025] The system light source 1 is an LED point light source, a laser point light source or other light sources that meet the detection intensity requirements. The light emitted by the light source enters the system under appropriate distance requirements and can be used as monitoring light.
[0026] After passing through the correction lens group 2, the light beam of the correction lens group 2 is transformed from divergent light into parallel light, which serves the purpose of collimating and eliminating aberrations of the incident light. It is a single lens, a double cemented lens or a combination of two lenses.
[0027] The beam splitter 3 has a 50:50 beam splitting effect on the parallel light. The incident light is reflected by the beam splitter 3 to reflect a part of the light beam to the next part of the system structure. The beam splitter 3 can be a plane beam splitter 3 or a three-dimensional beam splitter.
[0028] The parallel light from the primary and secondary reflectors 4 passes through the beam splitter and hits the secondary reflector after passing through the light hole between the primary mirrors, and is then reflected by the secondary reflector onto the mirror surface of the primary reflector. The focusing effect of the primary reflector emits parallel light for detection. The surface types of the primary and secondary reflectors 4 can be spherical or aspherical, as long as they meet the requirements of beam expansion.
[0029] The primary and secondary reflectors 4 are afocal laser beam expansion systems developed based on the card-type basic structure. Different from the traditional afocal reflective system, the structure refers to the Galilean laser beam expander. Its magnification (MP) can be expressed by beam divergence or beam diameter:
[0030]
[0031] It can be found that the output beam divergence decreases as the output beam diameter increases, and vice versa. Therefore, if a beam expander is used to shrink the beam, the beam diameter will decrease, but the beam divergence will increase. The price of a small beam is a large divergence angle. For this structure, on the one hand, the beam expander increases the beam area by the square of the magnification without significantly affecting the total energy contained in the beam, which reduces the power density and irradiance of the beam, thereby extending the life of the laser component, reducing the probability of laser-induced damage, and allowing the use of more economical coatings and optical components.
[0032] The photodetector 5 receives the light beam transmitted through the beam splitter 3 and carries the deflection information of the target reflector, extracts and resolves the formed light spot information, and uses a CCD, CMOS, PSD or QD detector.
[0033] The effects of the corrective lens group 2 on the light beam include the following specific parts:
[0034] The corrective lens group 2 of the light source part is completely the same as the corrective lens group 2 of the detector part. The corrective lens group 2 of the light source part plays a collimating role on the light beam, while the corrective lens group 2 of the detector part plays a focusing role on the light beam.
[0035] The material involved in the corrective lens assembly 2 is glass material.
[0036] The primary and secondary reflectors 4 have a beam expansion effect, and the structure of the primary and secondary reflectors 4 is an afocal system, which can be an improved Cassegrain structure, a Galilean beam expansion structure or a reflective beam expansion structure.
[0037] The detection dimension involved in the photoelectric detector 5 is a linear array detector or a planar array detector according to the deflection of the target reflector.
[0038] like Figure 1 As shown, the light passing through the primary mirror and the secondary mirror structure of the invention is parallel light, the beam splitter 3 is arranged behind the light hole of the primary mirror, the corrective lens group 2 is respectively arranged between the light source and the beam splitter and between the photodetector and the beam splitter, the light emitted by the light source 1 is parallel output light after passing through the corrective lens group 2, and is transmitted through the beam splitter 3 through the light hole 4 of the primary mirror to hit the secondary mirror 4, is reflected by the secondary mirror to the primary mirror surface, and is then reflected by the primary mirror surface 4 as parallel light to hit the target reflector. When the reflected light from the target reflector hits the beam splitter 3 through the original path, due to the reflection effect of the beam splitter 3, it passes through the mirror group between the photodetector 5 and the beam splitter 3, which is exactly the same as the corrective lens 2 group on the light source path, and is converged on the photodetector 5 to form an image.
[0039] like Figure 2 As shown, the first type of corrective lens group uses a single lens as the system corrective lens group; the second type uses a double-cemented achromatic lens as the corrective lens group; the third type uses a lens and a cemented lens combination as the corrective lens group. When using different types of corrective lens groups for monitoring imaging, there will be different imaging effects. When using a single lens, the focusing spot effect is poor, the aberration influence is large, and the application is limited in the field of angle monitoring; the use of a double-cemented achromatic lens eliminates the influence of chromatic aberration to a certain extent, reduces the size of the imaging spot, and optimizes the imaging effect; when using a combined lens group as the corrective lens group, the spot radius is significantly reduced, and the effect of eliminating the influence of aberration is obvious. The purpose of improving monitoring accuracy can be achieved by optimizing the corrective lens group.
[0040] like Figure 3As shown in the figure, when facing different monitoring needs, different correction lens groups are used to compare the imaging spot evaluation function. Table 1 is the parameters of the correction lens groups in two different replaceable modules. When the imaging spot radius needs to be smaller, the first group of correction lens groups is used. It can be seen from the figure that the spot is smaller than the second one, and the MTF function curve has a higher value at the cutoff frequency, and the imaging quality is better; when the imaging spot shape needs to be more uniform, the second group of correction lens groups is used. It can be seen from the figure that the spot is more uniform than the first shape, which is easier for spot extraction, but the MTF function curve has a lower value at the cutoff frequency, and the imaging quality is poor.
[0041] Table 1 Parameters of combined mirror set
[0042]
[0043]
[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A modularly designed catadioptric self-collimating angle measuring optical system, comprising a system light source (1), a correction lens group (2), a beam splitter (3), a primary and secondary reflector (4), and a photoelectric detector (5). It is characterized in that The system light source (1) emits light that is incident on a correction lens group (2). The correction lens group (2) is used to collimate the light beam. The parallel light that has passed through the correction lens group (2) is reflected by a beam splitter (3). The light beam passes through a light hole of a primary reflector and hits a secondary reflector. After being reflected by the secondary reflector, the light beam is diverged to a reflective surface of a primary reflector and is emitted again as parallel light to a target reflector.
2. A modularly designed catadioptric self-collimating angle measuring optical system according to claim 1, It is characterized in that The system light source (1) is an LED point light source, a laser point light source or other light sources that meet the detection intensity requirements. Under appropriate distance requirements, the light emitted by the light source can be used as monitoring light after entering the system.
3. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 1, It is characterized in that After passing through the correction lens group (2), the light beam of the correction lens group (2) is transformed from divergent light into parallel light, which serves the purpose of collimating and eliminating aberration of the incident light. The correction lens group (2) is a single lens, a double cemented lens or a combination of the two lenses.
4. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 1, It is characterized in that The beam splitter (3) performs a 50:50 beam splitting effect on parallel light. The incident light is reflected by the beam splitter (3) to reflect a portion of the light beam to the next part of the system structure. The beam splitter (3) can be a plane beam splitter (3) or a three-dimensional beam splitter.
5. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 1, It is characterized in that The parallel light of the primary and secondary reflectors (4) passes through the beam splitter and the light hole between the primary mirrors before hitting the secondary reflector, and then is reflected by the secondary reflector onto the mirror surface of the primary reflector. The focusing effect of the primary reflector emits parallel light for detection. The surface shape of the primary and secondary reflectors (4) can be a spherical mirror or an aspherical mirror, as long as the beam expansion function is met.
6. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 1, It is characterized in that The photoelectric detector (5) receives the light beam transmitted through the beam splitter (3) and carries the deflection information of the target reflector, extracts and resolves the formed light spot information, and uses a CCD, CMOS, PSD or QD detector.
7. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 3, It is characterized in that The effect of the corrective lens assembly (2) on the light beam includes the following specific parts: The light source part correction mirror group (2) is completely the same as the detector part correction mirror group (2); the light source part correction mirror group (2) plays a collimating role on the light beam, while the detector part correction mirror group (2) plays a focusing role on the light beam.
8. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 3, It is characterized in that The material involved in the corrective lens assembly (2) is selected to be glass material.
9. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 5, It is characterized in that The beam expansion effect of the primary and secondary reflectors (4) is that the structure of the primary and secondary reflectors (4) is an afocal system, which may be an improved Cassegrain structure, a Galilean beam expansion structure or a reflective beam expansion structure.
10. The modularly designed catadioptric self-collimating angle measuring optical system according to claim 6, It is characterized in that The detection dimension involved by the photoelectric detector (5) is a linear array detector or a planar array detector according to the deflection condition of the target reflector.