A zoom optical system entrance pupil diameter and position measuring device and method based on star point method

Abstract

The application provides a zoom optical system entrance pupil diameter and position measuring device and method based on a star point method, which comprises a light source generating system, a light source three-dimensional adjusting system, an adjusting objective table system, a light spot detector system and a light spot detection three-dimensional adjusting system; the light source generating system is arranged on the light source three-dimensional adjusting system; the adjusting objective table system is arranged between the light source three-dimensional adjusting system and the light spot detection three-dimensional adjusting system, and is used for installing a measured optical system and adjusting the measured optical system in azimuth and pitch angle; and the light spot detector system is arranged on the light spot detection three-dimensional adjusting system. The application converts the measured optical system entrance pupil diameter into a parallel light beam with the same caliber, the light beam is transmitted to the object side of the measured optical system infinitely, can be received conveniently by a detector, and the entrance pupil diameter of the measured optical system can be obtained directly through the translation of a translation table.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical system testing device, in particular to a zoom optical system entrance pupil diameter and position measuring device and method based on star point method. BACKGROUND

[0002] With the increasingly wide application of photoelectric imaging systems in civil and military fields, the performance indicators of photoelectric imaging systems, such as the action distance, are attracting much attention. In the civil field, photoelectric imaging systems are required to image the monitoring range as clearly as possible under different lighting conditions, especially in the evening or under insufficient lighting conditions, and should be able to image the scene target clearly. In the military field, due to the changing battlefield environment, photoelectric imaging systems are required to be able to detect the characteristics of targets at a longer distance (generally more than 50 km) in order to take timely measures. However, due to the large amount of attenuation of the target reflection or radiation energy by the atmosphere, the target signal received by the photoelectric imaging system is very weak, and therefore the photoelectric imaging system is required to have a larger relative aperture (i.e. a smaller F / #) to collect more target reflection or radiation energy. Therefore, the entrance pupil diameter of the photoelectric imaging system determines the key performance indicator of the system in collecting target energy, and also determines the action distance of the photoelectric imaging system.

[0003] An optical system is composed of optical glass, an aperture stop, a mechanical structure and a detector assembly. The optical glass is used to collect and focus the light of target radiation, and converge it to the focal plane of the optical system for the rear-end detector assembly to receive and realize imaging of the target. The aperture stop is used to limit the amount of light entering the optical system. The larger the aperture stop, the more light entering the system, and the higher the sensitivity of the detector to the target. However, if the aperture stop is too large, the projection height of the imaging light on the optical glass will increase, the aberration of the optical system will become larger, and the imaging clarity of the system will be affected.

[0004] Modern optical imaging systems can be divided into fixed focus optical systems and zoom optical systems according to whether the focal length changes. The principle diagram of the entrance pupil diameter of a fixed focus optical system is shown in Figure 1 The fixed focus optical system has a relatively simple structure, and the positions of the various optical glasses or optical components inside the optical system are relatively fixed.

[0005] As shown in Figure 1 , the entrance pupil of the optical system is actually the image (generally a virtual image) formed by the aperture optical front-end optical assembly of the aperture stop of the system. The conventional optical system entrance pupil diameter is measured by long working distance microscopy, which images the optical system entrance pupil on the object side of the system, and then measures the entrance pupil diameter D of the system through the digital display platform guide rail. The relative aperture or F / # of the optical system is calculated according to the focal length f' of the optical system.

[0006]

[0007] For zoom optical system, there are moving optical components inside the system, which can change the focal length of the system during the movement, but also change the entrance pupil position and diameter of the optical system. As shown in FIG. 2(a) and FIG. 2(b), due to the large zoom ratio of modern zoom optical system (generally more than 20x), the entrance pupil distance and diameter of the system change greatly.

[0008] For traditional fixed focus optical system, the method for testing the entrance pupil diameter of the system is to use a strong light source to illuminate the object side from the image side of the fixed focus optical system. The strong light source illuminates the physical aperture stop inside the fixed focus optical system after entering the optical system from the image side, and then a microscopic measurement system is used to test the size of the aperture stop image on the object side, which is the entrance pupil diameter D of the optical system. The testing principle is shown in FIG. 3. Figure 3

[0009] As we know, the microscopic measurement system generally magnifies the object and measures the characteristics of the object with high precision, which makes the effective working distance of the microscopic objective lens shorter. The working distance of a Γ = 20x microscopic objective lens is only about 0.5mm, and the working distance of a Γ = 1x or Γ = 0.5x microscopic objective lens is only about 10mm. Therefore, the method of using a microscopic objective lens to image and measure the entrance pupil can meet the requirements of testing the entrance pupil diameter of a short focal length fixed focus optical system. However, for a long focal length fixed focus optical system or a continuous zoom optical system, it is impossible to test the entrance pupil diameter by using the traditional method of testing the entrance pupil diameter of the optical system on the object side by a microscopic measurement system. The main reasons are as follows: (1) The total length of a long focal length fixed focus optical system is longer, and the system stop is generally located at the middle position of the optical system. Due to the long focal length of the optical system and the large focal length of each optical component, the aperture stop is generally close to the front end optical glass. The distance between the aperture stop and the image side main section of the front end optical component is less than half of the focal length of the front end optical component, which is taken as l' 光阑 = 0·5f 前端 According to the Newton formula, the position of the aperture stop image passing through the front end optical component can be calculated as follows:

[0010]

[0011] f′ 前端 is the focal length of the optical component before the aperture stop;

[0012] l′ 光阑 is the distance between the aperture stop and the image side main section of the front end optical component;

[0013] l 入瞳 is the distance between the system entrance pupil and the first optical glass of the system.

[0014] ​From the formula, when the focal length of the optical element before the aperture stop of the optical system is 10mm, the distance between the entrance pupil position of the optical system and the surface of the first optical glass of the optical system is 200mm, the traditional method of using a microscopic measurement system from the object side cannot test the entrance pupil diameter of the optical system. Moreover, with the increasing use of long focal length optical systems in modern civilian and military fields, the focal length of modern photoelectric imaging systems can even reach more than 1m, and the distance between the entrance pupil position and the first optical glass can even reach more than tens of meters. Especially for continuous zoom optical systems, the entrance pupil position changes greatly at different focal lengths. Therefore, the traditional method of using a microscopic measurement system to test the entrance pupil diameter of the optical system from the light entrance direction cannot complete the measurement of the entrance pupil diameter and the entrance pupil position of modern optical systems.

[0015] In order to solve the problem that the traditional microscopic measurement method cannot complete the measurement of the entrance pupil diameter of modern long focal length and zoom optical systems (the traditional microscopic measurement system can only complete the measurement of the entrance pupil diameter of optical systems with an entrance pupil distance of about 0mm-10mm), a new and efficient test method suitable for modern long entrance pupil distance optical systems is needed to evaluate the entrance pupil diameter of fixed focus or zoom optical systems and more objectively evaluate the collection ability of the optical system for target radiant energy. SUMMARY

[0016] The purpose of the present application is to solve the technical problem that the measurement method of the prior art cannot complete the measurement of the entrance pupil diameter of long focal length and zoom optical systems, and to provide a zoom optical system entrance pupil diameter measurement device and method based on the star point method, which converts the entrance pupil diameter of the measured optical system into a parallel light beam with the same aperture, which is transmitted to the object side of the measured optical system indefinitely, and can be easily received by a detector. The entrance pupil diameter of the measured optical system can be directly obtained by translation of the translation stage.

[0017] To achieve the above purpose, the technical scheme adopted by the present application is:

[0018] A zoom optical system entrance pupil diameter and position measurement device based on the star point method, characterized in that it comprises a light source generation system, a light source three-dimensional adjustment system, an adjustment objective table system, a light spot detector system and a light spot detection three-dimensional adjustment system.

[0019] The light source generating system is arranged on the light source three-dimensional adjustment system; the adjustment object table system is arranged between the light source three-dimensional adjustment system and the light spot detection three-dimensional adjustment system, and is used for mounting the measured optical system and adjusting the azimuth and the pitch angle of the measured optical system; the light spot detector system is arranged on the light spot detection three-dimensional adjustment system; the light source three-dimensional adjustment system, the adjustment object table system and the light spot detection three-dimensional adjustment system are used for adjusting the light source generating system and the light spot detector system to be located on the same optical path as the measured optical system.

[0020] The light source generating system is arranged at the image side focal plane of the measured optical system, emits a star point light source to the exit end of the measured optical system, and emits the light rays from the entrance end of the measured optical system after the light rays pass through the measured optical system.

[0021] The light spot detector system is arranged at the object side of the measured optical system, receives the light rays emitted from the entrance end of the measured optical system, and forms a light spot on the detection surface.

[0022] Further, the light source three-dimensional adjustment system comprises a light source height adjustment translation stage, a light source front-back adjustment translation stage, a light source left-right adjustment translation stage and a light source three-dimensional adjustment system controller; the light source front-back adjustment translation stage is arranged on the light source height adjustment translation stage, and the light source left-right adjustment translation stage is arranged on the light source front-back adjustment translation stage; the light source three-dimensional adjustment system controller is electrically connected with the light source height adjustment translation stage, the light source front-back adjustment translation stage and the light source left-right adjustment translation stage respectively, and is used for position adjustment.

[0023] Further, the light source generating system comprises a visible light point light source assembly, a visible light laser, a near-infrared laser, a short-wave infrared laser, a medium-wave infrared laser and a long-wave infrared laser arranged on the light source left-right adjustment translation stage; the fiber laser exit end points of the visible light laser, the near-infrared laser, the short-wave infrared laser, the medium-wave infrared laser and the long-wave infrared laser are located at the same conjugate position as the star point image of the visible light point light source assembly.

[0024] Further, the adjustment object table system comprises an azimuth angle displacement stage, a pitch angle displacement stage and an angle displacement stage controller; the azimuth angle displacement stage is arranged on the pitch angle displacement stage; and the angle displacement stage controller is electrically connected with the azimuth angle displacement stage and the pitch angle displacement stage respectively, and is used for controlling the angle adjustment of the azimuth angle displacement stage and the pitch angle displacement stage.

[0025] Further, the light spot detection three-dimensional adjustment system comprises a light spot detection height adjustment translation stage, a light spot detection front and back adjustment translation stage, a light spot detection left and right adjustment translation stage, and a detection receiving three-dimensional translation stage controller; the light spot detection front and back adjustment translation stage is arranged on the light spot detection height adjustment translation stage, the light spot detection left and right adjustment translation stage is arranged on the light spot detection front and back adjustment translation stage, and the detection receiving three-dimensional translation stage controller is electrically connected with the light spot detection height adjustment translation stage, the light spot detection front and back adjustment translation stage and the light spot detection left and right adjustment translation stage respectively, and is used for three-dimensional adjustment control.

[0026] Further, the light spot detector system comprises a visible light detector, a short-wave infrared detector, a medium-wave infrared detector and a long-wave infrared detector; the visible light detector, the short-wave infrared detector, the medium-wave infrared detector and the long-wave infrared detector are installed side by side on the light spot detection left and right adjustment translation stage along the moving direction of the left and right adjustment translation stage.

[0027] Further, the visible light point light source assembly comprises, in sequence along an optical axis, a microscopic objective lens, a star point scale plate, a ground glass, a halogen lamp light source and an ellipsoidal condenser; light emitted by the halogen lamp light source is condensed by the ellipsoidal condenser, converges on the ground glass, is scattered after passing through the ground glass, forms a uniform secondary plane light source to illuminate the star point scale plate, the star point scale plate is arranged on a focal plane of an object side of the microscopic objective lens, and forms a star point light source after imaging by the microscopic objective lens.

[0028] A zoom optical system entrance pupil diameter and position measurement method based on a star point method, which is characterized by comprising the following steps:

[0029] Step 1, a star point light source is generated by a light source generation system, the star point light source is adjusted to the vicinity of a focal plane of a measured optical system by a light spot detection three-dimensional adjustment system, a light spot diameter d1 and a light spot center point position O1 are measured on an A plane of the measured optical system, the light spot detector system is moved back by Fmm to reach a B plane, a light spot diameter d2 and a light spot center point position O2 are measured on the B plane, a distance l' of the star point light source from the focal plane of the measured optical system is calculated according to the difference between d1 and d2, and a distance y' of the star point light source from the focal point of the measured optical system is calculated according to the light spot center point positions O1 and O2 measured twice;

[0030] Step 2, the position of the star point light source is adjusted by a light source three-dimensional adjustment system according to the distance l' of the star point light source from the focal plane of the measured optical system and the distance y' of the star point light source from the focal point of the measured optical system, the angle of the measured optical system is adjusted by an object table system, so that the light spot diameters d1 and d2 on the A plane and the B plane are equal, and the light spot center point positions O1 and O2 are on the optical axis, and the measured optical system entrance pupil diameter D is obtained by combined measurement of the light spot detector system and the light spot detection three-dimensional adjustment system.入瞳 ;

[0031] Step 3, record the coordinate position of O1 point, and move the star point light source in the focal plane of the measured optical system by a distance y' through the light source three-dimensional adjustment system, and use the light spot detector system and the light spot detection three-dimensional adjustment system to measure the light spot center position of the exit light spot of the measured optical system on the A plane and the B plane again, calculate the distance s1 and s2 between the light spot center position on the A plane and the B plane and the optical axis of the measured optical system, and further calculate the entrance pupil distance L of the measured optical system.

[0032] Further, in the step 1, the calculation formula of the distance of the star point light source to the system focal plane is:

[0033]

[0034] Wherein, f is the focal length of the measured optical system;

[0035] The calculation formula of the distance of the star point light source from the focal point of the measured optical system is:

[0036]

[0037] Wherein, y2 is the distance of O2 point from the optical axis; y1 is the distance of O1 point from the optical axis.

[0038] Further, in the step 3, the calculation method of the entrance pupil distance L of the measured optical system is:

[0039]

[0040] Wherein, s1 is the distance between the center of the exit light spot of the off-axis star point light source on the A plane and the optical axis of the measured optical system; s2 is the distance between the center of the exit light spot of the off-axis star point light source on the B plane and the optical axis of the measured optical system.

[0041] Compared with the prior art, the present application has the beneficial technical effects as follows:

[0042] 1) The present application is based on the star point method for measuring the entrance pupil diameter and position of the zoom optical system, by setting a visible point light source assembly on the focal point of the measured optical system, the light beam within the entrance pupil diameter is transmitted to the object side of the measured optical system after being limited by the aperture diaphragm in the optical system, and the entrance pupil diameter of the measured optical system can be obtained by measuring the aperture of the exit light beam. Starting from the actual function of the aperture diaphragm in the optical system, the direct measurement method of the definition of the entrance pupil diameter of the optical system is broken through, and the problem that the working distance of the traditional microscope objective is short, and the entrance pupil diameter of the long entrance pupil distance optical system cannot be measured is solved.

[0043] 2) The present application is based on the star point method of zoom optical system entrance pupil diameter and position measurement device and method, the measured optical system entrance pupil diameter is converted into the same caliber parallel light beam, the light beam is transmitted to the measured optical system object side infinity, which can be conveniently received by the spot detector system, and the movement of the spot detection three-dimensional adjustment system can directly obtain the entrance pupil diameter of the measured optical system.

[0044] 3) The present application is based on the star point method of zoom optical system entrance pupil diameter and position measurement device and method, through the translation of the light source three-dimensional adjustment system, the point light source can be quickly adjusted to the focal plane of the measured optical system at any field of view position, so as to obtain the exit pupil diameter of the measured optical system at any field of view, and combined with the spatial position of the light spot measured by the light spot detector system under the condition of equal distance of the measured optical system, the entrance pupil position of the measured optical system can be quickly calculated.

[0045] 4) The present application is based on the star point method of zoom optical system entrance pupil diameter and position measurement device and method, by changing the wavelength range of the point light source and the detector of the light spot detector system, the entrance pupil diameter measurement of different working spectral range optical systems can be realized, which is suitable for visible light optical system, near-infrared optical system, short-wave infrared optical system, medium-wave infrared optical system and long-wave infrared optical system, and can meet the measurement of entrance pupil diameter of optical systems in all working spectral ranges. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 It is the existing fixed focus optical system exit pupil principle diagram;

[0047] Fig. 2(a) is the existing zoom optical system short focus entrance pupil diameter and entrance pupil position principle diagram;

[0048] Fig. 2(b) is the existing zoom optical system long focus entrance pupil diameter and entrance pupil position principle diagram;

[0049] Figure 3 It is the existing micro measurement system test optical system entrance pupil diameter principle diagram;

[0050] Figure 4 It is the corresponding relationship diagram of the equivalent optical system entrance pupil diameter and light transmission of the star point method based zoom optical system entrance pupil diameter and position measurement device embodiment of the present application;

[0051] Figure 5 It is the structure schematic diagram of the star point method based zoom optical system entrance pupil diameter and position measurement device embodiment of the present application;

[0052] Figure 6 It is the star point light source position adjustment principle diagram of the star point method based zoom optical system entrance pupil diameter and position measurement device embodiment of the present application;

[0053] Figure 7The measured optical system entrance pupil diameter test schematic diagram of the star point method based zoom optical system entrance pupil diameter and position measuring device embodiment of the present application;

[0054] Figure 8 The measured optical system entrance pupil position test schematic diagram of the star point method based zoom optical system entrance pupil diameter and position measuring device embodiment of the present application;

[0055] Figure 9 The structure schematic diagram of the visible light point source assembly in the star point method based zoom optical system entrance pupil diameter and position measuring device embodiment of the present application;

[0056] The sign of the reference numerals is explained as follows:

[0057] 1-light source height adjustment translation stage, 2-light source front and back adjustment translation stage, 3-light source left and right adjustment translation stage, 4-visible light point source assembly, 5-visible light laser, 6-near infrared laser, 7-short wave infrared laser, 8-middle wave infrared laser, 9-long wave infrared laser, 10-light source three-dimensional adjustment system controller, 11-azimuth angle displacement stage, 12-pitch angle displacement stage, 13-angle displacement stage controller, 14-splodge detection height adjustment translation stage, 15-splodge detection front and back adjustment translation stage, 16-splodge detection left and right adjustment translation stage, 17-detection receiving three-dimensional translation stage controller, 18-visible light detector, 19-short wave infrared detector, 20-middle wave infrared detector, 21-long wave infrared detector, 41-microscope objective, 42-star point scale plate, 43-ground glass, 44-halogen lamp light source, 45-ellipsoidal condenser; I-light source generation system, II-light source three-dimensional adjustment system, III-adjustment objective stage system, IV-splodge detector system, V-splodge detection three-dimensional adjustment system. DETAILED DESCRIPTION

[0058] The present application will be described in detail below in combination with the drawings and specific embodiments. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and the purpose is not to limit the protection scope of the present application.

[0059] The present application starts from the physical meaning of optical system entrance pupil, and proposes a method capable of measuring the entrance pupil diameter of fixed focus and zoom optical system. The method can measure the entrance pupil diameter of optical system with entrance pupil distance of 1∞~+∞, and is suitable for measuring the entrance pupil diameter of any optical system.

[0060] The definition of the optical system entrance pupil is that: the image formed by the front lens or lens group of the optical system aperture diaphragm in the optical system object space is called the entrance pupil, which is simply called the entrance pupil. The entrance pupil of the optical system limits the target light to enter the optical system spot aperture. According to the optical principle, any optical system can be simplified as an equivalent black box system, and the optical system entrance pupil diameter and focal length determine the relative aperture of the system, as shown in the principle diagram. Figure 4

[0061] For an optical system, the system entrance pupil actually limits the maximum accommodation envelope of a certain field of view, Figure 4 The middle red solid line represents the maximum accommodation envelope of the O° field of view light, and the aperture size is the same as the system entrance pupil diameter, and the reverse extension line of the system image side focusing light beam at a distance of f from the image plane is the entrance pupil of the system (the intersection plane of the red dashed line and the red solid line in the figure). Therefore, for any optical system, the entrance pupil diameter can also be represented as the aperture of the reverse extension line of the converging light of any field of view from the image plane at a distance of f from the image plane. In actual optical systems, due to the existence of the aperture diaphragm, the light from the image focal point will be limited by the aperture diaphragm, and the maximum spot aperture that can reach the object space is the entrance pupil diameter of the system. According to this principle, a point target light is emitted from the focal point of the measured optical system, and the point target light is incident into the optical system. Due to the limitation of the aperture diaphragm, the light beam representing the entrance pupil diameter can be emitted from the system object space through the front lens or lens group of the system. By measuring the diameter of the light spot, the entrance pupil diameter of the optical system can be obtained.

[0062] Referring to Figure 5 The zoom optical system entrance pupil diameter and position measuring device based on the star point method comprises a light source generating system I, a light source three-dimensional adjustment system II, an adjustment objective table system III, a light spot detector system IV and a light spot detection three-dimensional adjustment system V. The light source generating system I is arranged on the light source three-dimensional adjustment system II. The adjustment objective table system III is arranged between the light source three-dimensional adjustment system II and the light spot detection three-dimensional adjustment system V, and is used for installing the measured optical system and adjusting the azimuth and pitch angle of the measured optical system. The light spot detector system IV is arranged on the light spot detection three-dimensional adjustment system V.

[0063] ​The light source three-dimensional adjustment system II comprises a light source height adjustment translation stage 1 and a light source front and back adjustment translation stage 2 and a light source left and right adjustment translation stage 3 installed thereon; the visible light point light source assembly 4, the visible light laser 5, the near-infrared laser 6, the short-wave infrared laser 7, the medium-wave infrared laser 8 and the long-wave infrared laser 9 of the light source generating system I are all installed on the light source left and right adjustment translation stage 3 of the light source three-dimensional adjustment system II, and the fiber exit end points of the visible light laser 5, the near-infrared laser 6, the short-wave infrared laser 7, the medium-wave infrared laser 8 and the long-wave infrared laser 9 are in the same conjugate position as the star point of the visible light point light source assembly 4, and the light source three-dimensional adjustment system controller 10 is installed beside the light source generating system I to control the position adjustment of the three translation stages of the light source three-dimensional adjustment system II.

[0064] Referring to Figure 9 The visible light point light source assembly 4 is composed of a microscopic objective 41, a star point plate 42, a ground glass 43, a halogen tungsten lamp light source 44 and an ellipsoidal condenser 45. The adjustment stage system III is composed of an azimuth displacement stage 11 and a pitch displacement stage 12 installed at the lower side of the azimuth displacement stage 11, and is used to provide azimuth and pitch angle adjustment for the measured optical lens, and the angle displacement stage controller 13 is installed beside the adjustment stage system III to control the azimuth and pitch displacement stages. The light spot detector system IV comprises a visible light detector 18, a short-wave infrared detector 19, a medium-wave infrared detector 20 and a long-wave infrared detector 21, and the four detectors are installed side by side on the light spot detection three-dimensional adjustment system V. The light spot detection three-dimensional adjustment system V is composed of a light spot detection height adjustment translation stage 14, a light spot detection front and back adjustment translation stage 15 and a light spot detection left and right adjustment translation stage 16, and is used to perform three-dimensional translation adjustment on the four detector assemblies, and the detection receiving three-dimensional translation stage controller 17 is installed beside the light spot detection three-dimensional adjustment system V to control the light spot detection three-dimensional adjustment system V. The core diameters of the single-mode optical fibers are all not greater than 50 μm; the diameter of the star point plate 42 is Φ1 mm; the magnification of the microscopic objective 41 is Γ=10×; the material of the ground glass 43 is quartz, and the aperture is Φ30 mm; the effective stroke of the light source left and right adjustment translation stage 3 is 300 mm; and the effective stroke of the light spot detection left and right adjustment translation stage 16 is 300 mm.

[0065] The light emitted by the halogen tungsten light source 44 is converged on the frosted glass 43 after being focused by the ellipsoidal focusing mirror 45, and the light is scattered after passing through the frosted glass 43, forming a uniform secondary surface light source to illuminate the star point reticle 42 installed in front of it. The star point reticle is installed on the object plane of the microscope objective 41, and the image is formed on the image plane through the microscope objective 41, forming an ideal star point light source. The visible laser 5 emits monochromatic visible light energy, which is transmitted through single-mode light transmission to form an ideal visible monochromatic point light source at the fiber exit end. The near-infrared laser 6 emits monochromatic near-infrared light energy, which is transmitted through single-mode light transmission to form an ideal near-infrared point light source at the fiber exit end. The short-wave infrared laser 7 emits monochromatic short-wave infrared light energy, which is transmitted through single-mode light transmission to form an ideal short-wave infrared monochromatic point light source at the fiber exit end. The medium-wave infrared laser 8 emits monochromatic medium-wave infrared light energy, which is transmitted through single-mode light transmission to form an ideal medium-wave infrared monochromatic point light source at the fiber exit end. The long-wave infrared laser 9 emits monochromatic medium-wave infrared light energy, which is transmitted through single-mode light transmission to form an ideal medium-wave infrared monochromatic point light source at the fiber exit end. The fiber exit ends of the visible laser 5, the near-infrared laser 6, the short-wave infrared laser 7, the medium-wave infrared laser 8, and the long-wave infrared laser 9 are installed side by side, and the fiber exit ends are mutually conjugate with respect to the light source left-right adjustment translation stage 3. The star point image formed by the visible point light source assembly 4 is also conjugate with each laser monochromatic light source fiber exit end. In actual testing, the three translation adjustment degrees of freedom of the light source three-dimensional adjustment system II can adjust the six point light sources in the up-down, left-right, and high-low directions relative to the focal position of the measured optical system to test the entrance pupil diameter and entrance pupil position of the measured optical system under different field angles. The six point light sources generated by the light source generation system I are transmitted in the form of spherical waves, and after passing through the measured optical system, the spherical waves are collimated into plane waves, which are emitted as parallel light beams to the object side of the measured optical system for detection and reception by the spot detection system. The adjustment stage system III is installed in front of the light source generation system I to provide azimuth angle and elevation angle adjustment for the measured optical system, and the optical axis of the measured optical system is in a horizontal state. The spherical waves emitted by the light source generation system I are collimated by the measured optical system and incident on the spot detector system IV as parallel light beams. The point light source and the detector are selected according to the working wavelength of the measured optical system. The detection relative position is adjusted by controlling the spot detection three-dimensional adjustment system V to enable it to receive the parallel light beam energy emitted by the measured optical system. The spot detection left-right adjustment translation stage 16 of the spot detection system IV is controlled to move, enabling the detection to measure the completed spot emitted by the measured optical system. The left-right translation amount of the spot detection three-dimensional adjustment system V and the position of the spot received on the detector can be used to calculate the entrance pupil diameter of the measured optical system.

[0066] The application further provides a zoom optical system entrance pupil diameter and position measuring method based on the star point method, a light source generating system I can generate ideal point light sources of different test spectral ranges, spherical wave light energy emitted by the ideal point light sources is incident to a measured optical system, and is collimated as plane wave light after passing through the measured optical system, and the plane wave aperture is the entrance pupil diameter of the measured optical system (the plane wave aperture is limited by the aperture stop, and the plane wave aperture represents the entrance pupil diameter of the measured optical system), the plane wave aperture of the measured optical system is tested by a light spot detector system IV, Figure 6 as shown.

[0067] 1. Adjusting the star point light source to be located at the focal point position of the measured optical system in the image side

[0068] First, the selected star point light source is adjusted to be located near the focal plane of the measured optical system by a light source three-dimensional adjustment system II, the light spot diameter d1 and the light spot position O1 of the outgoing light spot are measured in the A plane of the measured optical system, the light spot detector system IV is moved 200 mm to the B plane after the image, and the light spot diameter d2 and the light spot position O2 are measured in the B plane, the distance between the star point light source and the system focal plane (i.e. the defocus amount) can be calculated by the difference between d1 and d2, and the distance between the star point light source and the focal point of the measured optical system can be calculated by the light spot center positions O1 and O2 measured twice.

[0069]

[0070] In the formula, y2 is the distance between the O2 point and the optical axis;

[0071] y1 is the distance between the O1 point and the optical axis;

[0072] f is the focal length of the measured optical system.

[0073]

[0074] In the formula, d1 is the light spot diameter of the outgoing light spot in the A plane;

[0075] d2 is the light spot diameter of the outgoing light spot in the B plane;

[0076] f is the focal length of the measured optical system.

[0077] The diameters and center positions of the outgoing light spots in the A plane and the B plane are measured, the distance between the star point light source and the measured optical system is calculated according to the formula 1 and the formula 2, the position of the star point light source is adjusted by the light source three-dimensional adjustment system II, and the angle of the measured optical system is adjusted by the object table system III, so that the star point light source is located at the focal point position F of the measured optical system, and the test optical diagram as shown in Figure 7 is obtained.

[0078] 2. Test of the diameter of the entrance pupil of the optical system under test

[0079] By adjusting step 1, the diameters d1 and d2 of the exit light spots in the A plane and the B plane are equal, and the center points of the light spots are on the optical axis. By the combination of the light spot detector system IV and the light spot detection three-dimensional adjustment system V, the diameter D of the entrance pupil of the optical system under test can be obtained. 入瞳 .

[0080] 3. Test of the distance of the entrance pupil of the optical system under test

[0081] After the focal point F of the optical system under test and the diameter D of the entrance pupil of the optical system under test are determined, the coordinate position of the point O1 is recorded, and the star point light source is moved by a distance y' in the focal plane of the optical system under test. The center positions of the exit light spots of the optical system under test in the A plane and the B plane are measured again by the light spot detector system IV and the light spot detection three-dimensional adjustment system V. The distances s1 and s2 of the center positions of the light spots in the A plane and the B plane from the optical axis of the optical system under test are calculated, as shown in formula 3. Figure 8 The distance L of the entrance pupil of the optical system under test can be calculated according to formula 3.

[0082]

[0083] In the formula, L is the distance of the entrance pupil of the optical system under test.

[0084] s1 is the distance of the center of the exit light spot of the off-axis star point light source in the A plane from the optical axis of the optical system under test.

[0085] s2 is the distance of the center of the exit light spot of the off-axis star point light source in the B plane from the optical axis of the optical system under test.

[0086] The method for measuring the diameter and position of the entrance pupil of the zoom optical system based on the star point method of the present application converts the diameter of the entrance pupil of the optical system into the diameter of the ideal light spot carrying the diameter of the entrance pupil for measurement, avoids the problem that the diameter of the entrance pupil cannot be measured due to the excessively large distance of the entrance pupil, and is suitable for measuring the diameter and position of the entrance pupil of any optical system.

[0087] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A star point method based zoom optical system entrance pupil diameter and position measuring device, characterized in that: comprising a light source generating system (I), a light source three-dimensional adjustment system (II), an adjustment stage system (III), a light spot detector system (IV) and a light spot detection three-dimensional adjustment system (V); the light source generating system (I) is arranged on the light source three-dimensional adjustment system (II); the adjustment stage system (III) is arranged between the light source three-dimensional adjustment system (II) and the light spot detection three-dimensional adjustment system (V), used for installing the measured optical system and adjusting the azimuth and pitch angle of the measured optical system; the light spot detector system (IV) is arranged on the light spot detection three-dimensional adjustment system (V); the light source three-dimensional adjustment system (II), the adjustment stage system (III) and the light spot detection three-dimensional adjustment system (V) are used for adjusting the light source generating system (I) and the light spot detector system (IV) to be in the same optical path with the measured optical system; the light source generating system (I) is arranged at the image side focal plane of the measured optical system, the light source generating system (I) emits a star point light source and emits to the exit end of the measured optical system, and the light ray is emitted from the entrance end of the measured optical system after passing through the measured optical system; the light spot detector system (IV) is arranged at the object side of the measured optical system, receives the light ray emitted from the entrance end of the measured optical system, and forms a light spot on the detection surface thereof; the light source three-dimensional adjustment system (II) comprises a light source height adjustment translation stage (1), a light source front and back adjustment translation stage (2), a light source left and right adjustment translation stage (3) and a light source three-dimensional adjustment system controller (10); the light source front and back adjustment translation stage (2) is arranged on the light source height adjustment translation stage (1), and the light source left and right adjustment translation stage (3) is arranged on the light source front and back adjustment translation stage (2); the light source three-dimensional adjustment system controller (10) is electrically connected with the light source height adjustment translation stage (1), the light source front and back adjustment translation stage (2) and the light source left and right adjustment translation stage (3) respectively, and used for position adjustment. the light source generating system (I) comprises a visible light point source assembly (4), a visible light laser (5), a near-infrared laser (6), a short-wave infrared laser (7), a medium-wave infrared laser (8) and a long-wave infrared laser (9) arranged on the light source left and right adjustment translation stage (3); the fiber laser exit end points of the visible light laser (5), the near-infrared laser (6), the short-wave infrared laser (7), the medium-wave infrared laser (8) and the long-wave infrared laser (9) are in the same conjugate position with the star point image of the visible light point source assembly (4). the adjustment stage system (III) comprises an azimuth angle displacement stage (11), a pitch angle displacement stage (12) and an angle displacement stage controller (13); the azimuth angle displacement stage (11) is arranged on the pitch angle displacement stage (12); the angle displacement stage controller (13) is electrically connected with the azimuth angle displacement stage (11) and the pitch angle displacement stage (12) respectively, and used for controlling the angle adjustment of the azimuth and pitch angle displacement stages. ​ ​ The position of the star point light source is adjusted by the light source three-dimensional adjustment system (II), the angle of the measured optical system is adjusted by the objective table system (III), the light spot diameters of the exit light spot on the A plane and the B plane of the measured optical system are equal, the center point positions of the light spot are on the optical axis, the measured optical system entrance pupil diameter is obtained through the combination measurement of the light spot detector system (IV) and the light spot detection three-dimensional adjustment system (V). and and .​​ 2. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 1, characterized by: ​ 3. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 2, characterized by: ​ 4. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 3, characterized by: ​ 5. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 4, characterized by: The light spot detection three-dimensional adjustment system (V) comprises a light spot detection height adjustment translation stage (14), a light spot detection front and back adjustment translation stage (15), a light spot detection left and right adjustment translation stage (16) and a detection receiving three-dimensional translation stage controller (17); the light spot detection front and back adjustment translation stage (15) is arranged on the light spot detection height adjustment translation stage (14), the light spot detection left and right adjustment translation stage (16) is arranged on the light spot detection front and back adjustment translation stage (15), and the detection receiving three-dimensional translation stage controller (17) is electrically connected with the light spot detection height adjustment translation stage (14), the light spot detection front and back adjustment translation stage (15) and the light spot detection left and right adjustment translation stage (16) respectively and is used for controlling three-dimensional adjustment.

6. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 5, characterized by: The light spot detector system (IV) comprises a visible light detector (18), a short-wave infrared detector (19), a medium-wave infrared detector (20) and a long-wave infrared detector (21); the visible light detector (18), the short-wave infrared detector (19), the medium-wave infrared detector (20) and the long-wave infrared detector (21) are installed side by side on the light spot detection left and right adjustment translation stage (16) along the moving direction of the left and right adjustment translation stage (16).

7. The star-point method based zoom optical system entrance pupil diameter and position measurement apparatus according to claim 6, characterized by: The visible light point source assembly (4) comprises, in sequence along an optical axis, a microscopic objective lens (41), a star point scale plate (42), a ground glass (43), a halogen tungsten lamp light source (44) and an ellipsoidal condenser (45); light emitted by the halogen tungsten lamp light source (44) is condensed by the ellipsoidal condenser (45) and then converges on the ground glass (43), the light is scattered after passing through the ground glass (43), a uniform secondary plane light source illuminates the star point scale plate (42), the star point scale plate (42) is arranged on the object focal plane of the microscopic objective lens (41) and forms a star point light source after imaging by the microscopic objective lens (41).

8. A method for measuring the diameter and position of the entrance pupil of a zoom optical system based on the star point method, using the apparatus for measuring the diameter and position of the entrance pupil of a zoom optical system based on the star point method according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: Step 1, the star point light source is generated by the light source generating system (I), the star point light source is adjusted to the vicinity of the focal plane of the measured optical system through the light spot detection three-dimensional adjustment system (V), and the outgoing light spot diameter and the light spot center point position are measured at the object plane A of the measured optical system using the light spot detector system (IV) and the light spot center point position The light spot detector system (IV) is moved backward by Fmm to reach the B plane, the outgoing light spot diameter and the light spot center point position are measured at the B plane and the light spot center point position The distance l' from the star point light source to the focal plane of the measured optical system is calculated through the difference between and The distance y' from the star point light source to the focal point of the measured optical system is calculated through the light spot center point positions and measured twice. Step 2, according to the distance l' of the star point light source deviating from the focal plane of the measured optical system and the distance y' deviating from its focal point, the position of the star point light source is adjusted through the light source three-dimensional adjustment system (II), the angle of the measured optical system is adjusted through the stage system (III), so that the spot diameters of the outgoing light spots in the A plane and the B plane are equal, and the center point positions of the light spots are on the optical axis, and the measured optical system entrance pupil diameter is obtained through the combination measurement of the light spot detector system (IV) and the light spot detection three-dimensional adjustment system (V) and and ;​​ Step 3, record The coordinate position of the point, and move the star point light source in the focal plane of the measured optical system through the light source three-dimensional adjustment system (II) Distance, and measure the light spot center position of the exit light spot of the measured optical system on the A plane and the B plane again using the light spot detector system (IV) and the light spot detection three-dimensional adjustment system (V), and calculate the distance between the light spot center position on the A plane and the B plane and the optical axis of the measured optical system And , and further calculate the entrance pupil distance of the measured optical system .

9. The method according to claim 8, wherein: In step 1, the calculation formula of the distance from the star point light source to the focal plane of the system is: ； wherein, f is the focal length of the optical system under test; The calculation formula of the distance from the star point light source to the focal point of the measured optical system is: ； wherein is the distance of the point from the optical axis; is the distance of the point from the optical axis.

10. The method according to claim 9, wherein: The entrance pupil distance of the measured optical system in step 3 is calculated as: ； wherein is the distance of the exit spot of the off-axis star point light source from the optical axis of the measured optical system at the center of the A plane; is the distance of the exit spot of the off-axis star point light source from the optical axis of the measured optical system at the center of the B plane.

Images