CN112068296B - Large-view-field collimator - Google Patents
Large-view-field collimator Download PDFInfo
- Publication number
- CN112068296B CN112068296B CN202010892482.1A CN202010892482A CN112068296B CN 112068296 B CN112068296 B CN 112068296B CN 202010892482 A CN202010892482 A CN 202010892482A CN 112068296 B CN112068296 B CN 112068296B
- Authority
- CN
- China
- Prior art keywords
- field
- view
- reflector
- collimator
- axis
- 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
Images
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
- G02B17/0605—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using two curved mirrors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0207—Details of measuring devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0292—Testing optical properties of objectives by measuring the optical modulation transfer function
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
The invention provides a large-view-field collimator which comprises a reflector group forming an off-axis reflective optical system, wherein reflectors positioned on two sides in the reflector group respectively rotate to reflectors on opposite sides by a preset angle, the view field of the large-view-field collimator is a rectangular view field, the view field in the X-axis direction is far larger than that in the Y-axis direction, the Y-axis is in the vertical direction, and the X-axis is in the horizontal direction which is in the same direction with the rotating shaft of the reflectors. The large-view-field collimator provided by the invention has the characteristics of large view field, high imaging quality and low manufacturing difficulty, and can realize the test and calibration of a wide-view-field, multi-spectral-segment and high-resolution optical system.
Description
Technical Field
The invention relates to the technical field of aviation and aerospace optical measurement, in particular to an off-axis reflective large-view-field collimator.
Background
The Modulation Transfer Function (MTF) is an important index for evaluating the imaging quality of an optical system or a complete machine of an aviation camera and an aerospace camera, and a final optical image acquired by the camera is closely related to the MTF of the complete machine of the camera. The laboratory static MTF test is an important link in the camera development process, the complete machine static MTF test is generally completed by adopting an imaging method of the collimator tube and a target in a matching way, and the structural type and the imaging quality of the collimator tube directly influence the test precision and the test efficiency of the MTF test.
The structure types of the prior collimator used for the laboratory static MTF test of the camera comprise a refraction type collimator and a reflection type collimator, wherein the refraction type collimator and the reflection type collimator have larger view fields and can effectively improve the test efficiency, but are influenced by optical materials, the refraction type collimator is not suitable for the static MTF test of a wide-spectrum multispectral camera, the reflection type collimator can realize full-spectrum imaging, and the refraction type collimator has inherent advantages in the aspect of the static MTF test of the wide-spectrum multispectral camera. The reflecting parallel light pipe comprises a coaxial reflecting type and an off-axis reflecting type, the coaxial reflecting type parallel light pipe is blocked by a center, so that the imaging quality is limited, and the off-axis reflecting type parallel light pipe has the characteristics of larger view field and better imaging quality compared with the coaxial type parallel light pipe, so that the testing precision and efficiency of the static MTF test of the multispectral camera with the large view field can be improved.
The invention discloses a multispectral reflective collimator in the patent application with the application number of 201611253370.1, which adopts an off-axis two-reflective optical system type, and a primary mirror and a secondary mirror of the multispectral reflective collimator are opposite in horizontal position and staggered in height position. The technical scheme can meet the application of wide-band multispectral testing, but has the defects that the imaging field of view of the system is small (the image height field of view is only +/-18 mm), the MTF cutoff frequency is low (20lp/mm), and the static MTF testing requirement of the large-field high-resolution aerospace camera optical system cannot be met.
Disclosure of Invention
The invention aims to solve the problems of small imaging field of view and low MTF cut-off frequency of the existing multispectral off-axis reflective collimator, and provides a large-field-of-view collimator which is arranged by rotating a reflector of an off-axis reflective optical system by a preset angle so as to increase the field of view of the collimator and be beneficial to improving the MTF testing efficiency of a multispectral camera with a large field of view.
In order to achieve the purpose, the invention adopts the following specific technical scheme:
the invention provides a large-view-field collimator which comprises a reflector group forming an off-axis reflective optical system, wherein reflectors positioned on two sides in the reflector group respectively rotate to reflectors on opposite sides by preset angles, the view field of the large-view-field collimator is a rectangular view field, the view field in the X-axis direction is larger than the view field in the Y-axis direction, the Y-axis is in the vertical direction, and the X-axis is in the horizontal direction which is in the same direction with the rotating shaft of the reflectors.
Preferably, each reflector is connected with a light barrier for blocking stray light.
Preferably, the surface of the light barrier is provided with a delustering insection.
Preferably, the light barrier is made of aluminum alloy.
Preferably, the surface of the light-blocking panel is subjected to a blackening treatment.
Preferably, the reflector group comprises two reflectors, and both the reflectors are rectangular concave spherical reflectors.
Preferably, the two reflectors are a first reflector and a second reflector, respectively, and the focal power of the first reflector is smaller than that of the second reflector.
Preferably, the curvature radius of the first reflector is-3600 mm ≦ r1 ≦ 3200mm, and the preset angle of rotation is-3 ° ≦ θpNot more than-2 degrees, the curvature radius of the second reflecting mirror is not less than-4000 mm and not more than r2 and not more than-3600 mm, and the preset angle of rotation is not less than 5 degrees and not more than thetasNot more than 6 degrees, and the distance between the first reflector and the second reflector is 800 mm-1200 mm.
Preferably, the large field of view collimator further comprises a target located at the image plane of the off-axis reflective optical system.
Preferably, the distance between the second reflecting mirror and the target is 1000 mm-1500 mm.
The invention can obtain the following technical effects:
(1) the imaging field of view is large: the large-view-field collimator disclosed by the invention adopts an off-axis reflective optical structure to realize multi-spectral-band imaging; by releasing the rotational freedom of the reflector, the view field of the collimator can be obviously enlarged, and the test efficiency of the large-view-field multispectral camera MTF test can be improved.
(2) The imaging quality is high: the focal power of the reflector is reasonably distributed, the imaging quality is close to the diffraction limit while the large visual field is realized, and the relative distortion is better than 0.01 percent; meanwhile, stray light is eliminated by adopting the light barrier, so that the imaging effect is further improved.
(3) The manufacturing difficulty is low: the reflector of the large-view-field collimator provided by the invention is a spherical reflector, and the manufacturing difficulty is low.
Drawings
FIG. 1 is a schematic diagram of a large field of view collimator according to one embodiment of the present invention;
FIG. 2 is a schematic view of the rotation direction of the mirror group according to one embodiment of the present invention;
FIG. 3 is a schematic diagram of an MTF test curve according to a first embodiment of the present invention;
FIG. 4 is a schematic diagram of a distorted network of a collimator with a large field of view according to an embodiment of the present invention.
Wherein the reference numerals include: the device comprises a first reflector 1, a second reflector 2, a target 3, a first light barrier 4 and a second light barrier 5.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.
The large field of view collimator provided by the embodiments of the present invention will be described in detail below.
FIG. 1 shows a configuration of a large field of view collimator according to one embodiment of the present invention.
As shown in fig. 1, the collimator with large field of view provided by the embodiment of the present invention includes: the reflecting mirror group and the target 3 form an off-axis reflecting optical system to realize multi-spectral-band imaging; the target 3 is located at the image surface of the off-axis reflective optical system, and after the target 3 pattern is reflected by the off-axis reflective optical system, infinite parallel light of the target 3 pattern is formed and is used for MTF test of the multi-spectrum optical system.
The off-axis reflective optical system can be an off-axis two-reflective optical system, an off-axis three-reflective optical system or an off-axis four-reflective optical system, and the like.
The reflecting mirror group forming the off-axis two-reflection optical system consists of two reflecting mirrors, the reflecting mirror group forming the off-axis three-reflection optical system consists of three reflecting mirrors, and the reflecting mirror group forming the off-axis four-reflection optical system consists of four reflecting mirrors. The off-axis two-reflection optical system is taken as an example for explanation, and the off-axis three-reflection optical system and the off-axis four-reflection optical system can be obtained by the same principle.
The reflector group comprises a first reflector 1 and a second reflector 2, under the coordinate system shown in fig. 1, the positions of the first reflector 1 and the second reflector 2 are arranged oppositely in the Z-axis direction, and the positions of the first reflector 1 and the second reflector 2 are arranged in a way of being staggered by a certain distance in the y-axis direction.
In an embodiment of the present invention, the first reflector 1 and the second reflector 2 are concave reflectors whose surface shapes are spherical surfaces, and the concave spherical reflectors can reduce the difficulty of manufacturing the collimator with a large field of view.
Because the concave spherical reflector has the freedom degrees of radius, position and the like, the freedom degrees of radius, position and the like of the off-axis two-reflection optical system can be released, and the field of view is enlarged.
The first mirror 1 and the second mirror 2 may be rectangular concave spherical mirrors, so that the field of view of the off-axis two reflective optical system is a rectangular field of view.
Of course, the first reflecting mirror 1 and the second reflecting mirror 2 may be formed in an aspherical surface, a free-form surface, or the like.
In order to increase the degree of freedom of the off-axis two-reflection type optical system, the degree of freedom of the rotation angle of the reflector should be released in addition to the degrees of freedom of radius, position and the like, so that off-axis aberration can be balanced, and the field of view of the off-axis two-reflection type optical system can be further expanded.
Fig. 2 shows the direction of rotation of the mirror group according to an embodiment of the invention.
As shown in fig. 2, the first reflecting mirror 1 is rotated counterclockwise by a preset angle θ around the x-axis under the coordinate system shown in fig. 2pI.e. the first mirror 1 is rotated about the x-axis by theta in the direction of the second mirror 2pThe rotation angle of the first reflecting mirror 1 is thetap(ii) a Rotating the second reflector 2 clockwise around the X-axis by a preset angle thetasI.e. the second mirror 2 is rotated about the X-axis in the direction of the first mirror 1 by thetasThe angle of rotation of the second reflector 2 is thetasThe view field of the large view field collimator in the X-axis direction is far larger than that in the Y-axis direction.
θpTheta is within the range of-3 degrees to less than or equal top≤-2°，θsThe range of theta is more than or equal to 5 degreessNot more than 6 degrees, the curvature radius of the first reflector 1 is-3600 mm not more than r1 not more than-3200 mm, the curvature radius of the second reflector 2 is-4000 mm not more than r2 not more than-360 mm0mm, the distance between the first reflector 1 and the second reflector 2 is 800 mm-1200 mm, and the distance between the second reflector 2 and the target 3 is 1000 mm-1500 mm.
By releasing the rotational freedom degree of the first reflecting mirror 1 and the second reflecting mirror 2, the view field of the large-view-field parallel light tube in the X direction is obviously enlarged, and the improvement of the MTF testing efficiency of the large-view-field multispectral camera is facilitated.
As a preferred embodiment, the optical power of the first mirror 1 is smaller than the optical power of the second mirror 2. By reasonably distributing the focal power of the first reflecting mirror 1 and the second reflecting mirror 2, the imaging quality is close to the diffraction limit while the large field of view is realized, and the relative distortion is better than 0.01 percent.
The first reflector 1 and the second reflector 2 may be made of metal alloy, microcrystalline material, or the like.
Returning to fig. 1, after the pattern of the target 3 passes through the second reflecting mirror 2 and the first reflecting mirror 1 in sequence, the parallel light forming the pattern of the target 3 is infinity, and is used for MTF test of the multi-spectrum optical system. The pattern of the target 3 is a rectangular pattern, and a light and dark stripe pattern with equal distance or gradually changed distance can be adopted, and the long side direction of the stripe pattern is parallel to the X-direction view field.
In one embodiment of the present invention, a first light-blocking plate 4 is connected to the first reflecting mirror 1, and the first light-blocking plate 4 is located in a blank area formed by the reflected light between the first reflecting mirror 1 and the second reflecting mirror 2 and the reflected light between the second reflecting mirror 2 and the target 3, and does not interfere with the optical path. Similarly, the second reflector 2 is connected with a second light-blocking plate 5, and the second light-blocking plate 5 is located in a blank area formed by parallel light formed after being reflected by the first reflector 1 and reflected light between the first reflector 1 and the second reflector 2, and does not interfere with a light path. The first reflector 1, the second reflector 2, the first light barrier 4 and the second light barrier 5 are arranged in the closed space, aluminum alloy materials can be selected for the materials of the first light barrier 4 and the second light barrier 5, extinction insections are processed on the surfaces of the first light barrier 4 and the second light barrier 5, blacking is carried out on the surfaces of the first light barrier 4 and the second light barrier 5 by adopting a black dyeing or black paint spraying mode, and the influences of primary stray light and secondary stray light can be effectively eliminated.
Example one
The specific parameters of the large field of view collimator are shown in the following table:
| serial number of optical elements | Radius of curvature (mm) | Rotation angle | Spacing distance (mm) |
| First reflector 1 | -3546 (concave spherical surface) | -2.49 | 992 (spaced from the second reflector 2) |
| Second reflector 2 | -3821 (concave spherical surface) | 5.872 | 1321 (spaced distance from target 3) |
According to the specific parameters of the large-view-field collimator, the following parameters can be obtained: the focal length is larger than 3000mm, the X-direction view field is not smaller than +/-0.72 degrees, the Y-direction view field is not smaller than +/-0.1 degrees, the image height view field is converted, the X-direction is not smaller than +/-37.7 mm, and the Y-direction is not smaller than +/-5.2 mm; the spectral range is the full spectrum.
The MTF test is carried out by using the large-field collimator with the parameters, the MTF test curve is shown in FIG. 3, and as can be seen from the MTF test curve in FIG. 3, the transfer function is close to or equal to the diffraction limit, and the cut-off frequency is 50 lp/mm.
The distortion network of the large-field collimator is shown in fig. 4, and as can be seen from the distortion grid of fig. 4, the distortion of the large-field collimator is low, and the relative distortion is better than 0.01%.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.
Claims (7)
1. The large-view-field collimator is characterized by comprising a reflector group forming an off-axis reflective optical system, wherein reflectors positioned at two sides in the reflector group respectively rotate to reflectors at opposite sides by preset angles, the view field of the large-view-field collimator is a rectangular view field, the view field in the X-axis direction is larger than the view field in the Y-axis direction, the Y-axis is in the vertical direction, and the X-axis is in the horizontal direction which is in the same direction with the rotating shaft of the reflectors;
the reflector group comprises two reflectors which are rectangular concave spherical reflectors;
the two reflectors are respectively a first reflector and a second reflector, and the focal power of the first reflector is smaller than that of the second reflector;
the curvature radius of the first reflector is-3600 mm and r1 and 3200mm, and the preset angle theta of rotationpTheta is more than or equal to minus 3 degreespNot more than-2 degrees, the curvature radius of the second reflecting mirror is not less than-4000 mm and not more than r2 and not more than-3600 mm, and the preset angle of rotation is not less than 5 degrees and not more than thetasThe angle is not more than 6 degrees, and the distance between the first reflector and the second reflector is 800 mm-1200 mm;
the specific parameters of the large-field collimator are as follows: the field of view in the X-axis direction is less than or equal to minus 0.72 degrees or the field of view in the X-axis direction is more than or equal to 0.72 degrees, the field of view in the Y-axis direction is less than or equal to minus 0.1 degrees or the field of view in the Y-axis direction is more than or equal to 0.1 degrees, the image height field is converted, the X-axis direction is less than or equal to minus 37.7mm or the X-axis direction is more than or equal to 37.7mm, the Y-axis direction is less than or equal to minus 5.2mm or the Y-axis direction is more than or equal to 5.2 mm; the spectral range is the full spectrum.
2. The large-field collimator as claimed in claim 1, wherein each reflector is connected with a light barrier for blocking stray light.
3. The large-field collimator as claimed in claim 2, wherein the light barrier has a surface with extinction insections.
4. The large-field collimator as claimed in claim 3, wherein the light barrier is made of aluminum alloy.
5. The large-field collimator as claimed in claim 2 or 3, wherein the surface of said light barrier is blackened.
6. The large field of view collimator of claim 1, further comprising a target located at an image plane of said off-axis reflective optical system.
7. The large field of view collimator of claim 6, wherein said second reflecting mirror is spaced from said target by a distance of 1000mm to 1500 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010892482.1A CN112068296B (en) | 2020-08-31 | 2020-08-31 | Large-view-field collimator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010892482.1A CN112068296B (en) | 2020-08-31 | 2020-08-31 | Large-view-field collimator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112068296A CN112068296A (en) | 2020-12-11 |
| CN112068296B true CN112068296B (en) | 2022-04-26 |
Family
ID=73660522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010892482.1A Active CN112068296B (en) | 2020-08-31 | 2020-08-31 | Large-view-field collimator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112068296B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113702007B (en) * | 2021-09-02 | 2023-09-19 | 孝感华中精密仪器有限公司 | Calibration device and calibration method for off-axis beam axial difference |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204831220U (en) * | 2015-05-21 | 2015-12-02 | 秦皇岛本征晶体科技有限公司 | Calcirm -fluoride optical flat two sides depth of parallelism high accuracy testing arrangement |
| CN107728300B (en) * | 2017-10-26 | 2019-12-06 | 宁波源禄光电有限公司 | Small reflective off-axis telescopic system with wide view field and large relative aperture |
-
2020
- 2020-08-31 CN CN202010892482.1A patent/CN112068296B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112068296A (en) | 2020-12-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106383401B (en) | A kind of extremely wide field of view off-axis incidence optical imaging system | |
| US11043521B2 (en) | Freeform surface off-axial three-mirror imaging system | |
| CN101855585B (en) | Image-forming optical system and distance measuring device | |
| US20190219800A1 (en) | Method of designing freeform surface off-axial three-mirror imaging system | |
| US8011793B2 (en) | Wide field four mirror telescope using off-axis aspherical mirrors | |
| US20190025574A1 (en) | Method for Designing Imaging Objective Lens System of Anamorphic Magnification | |
| US11386246B2 (en) | Method for designing hybrid surface optical system | |
| US9057964B2 (en) | Imaging optics and projection exposure installation for microlithography with an imaging optics | |
| CN110161717B (en) | Global surface reflection collimator optical system without obscuration | |
| CN112068296B (en) | Large-view-field collimator | |
| CN111896480B (en) | Off-axis broadband reflection type simultaneous polarization imaging system | |
| CN206224041U (en) | A kind of extremely wide field of view computer-aided alignment | |
| CN110908098B (en) | Large-view-field distortion-eliminating off-axis reflection optical system and design method | |
| CN103901593B (en) | A kind of from axle without blocking extreme ultra-violet lithography object lens | |
| CN116124415A (en) | Schlieren measurement system and schlieren measurement method | |
| CN111025615B (en) | Optical system | |
| CN105866936B (en) | A kind of airborne ultra-wide angle whole world face reflective optical system | |
| CN114371548B (en) | Two-dimensional large-view-field imaging plane symmetrical free-form surface optical system | |
| CN113835205B (en) | Refractive and reflective imaging telescopic optical system | |
| CN210243983U (en) | Non-blocking global surface reflection collimator optical system | |
| CN208736353U (en) | A kind of detection focal length measures greatly the optical system of off axis paraboloidal mirror off axis | |
| CN113777779A (en) | Method for structure calculation and free-form surface type conversion of dual-focal-length deformation optical system | |
| CN109212734B (en) | Free-form surface-based sparse aperture two-reflection optical imaging system | |
| CN109163682B (en) | Detection device and method for long-focus large-off-axis-amount off-axis paraboloid | |
| CN113701882B (en) | Spectrometer optical system and design method thereof |
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 |