Focusing collimation projection optical system of infrared target simulator and design method of focusing collimation projection optical system

Abstract

The invention provides an infrared target simulator focusing collimation projection optical system and a design method thereof. The optical system is composed of a telescope objective, an intermediate field lens and a relay lens group. A source target and a background image generated by the infrared target simulator are input into the DMD and then are incident to the focusing collimation projection optical system through the DMD, the incident light firstly passes through the relay lens group and the intermediate field lens to generate a primary image of the image on the DMD, and then the primary image surface is collimated and projected to an entrance pupil of a tested photoelectric device through the telescope objective. According to the invention, optical material parameters are finely analyzed and matched, three infrared optical materials are adopted to form a lens group, a field lens is added to compress the aperture of a light beam, and only five lenses are used, so that achromatism and athermalization are realized while high transmittance is ensured. And a focusing lens group and a precise mechanical structure are arranged in the relay lens group, so that the target simulation requirement of photoelectric detection equipment such as a guide head at a wider working temperature range is met, and meanwhile, the requirement of obtaining a clear simulation target scene by matching detected photoelectric equipment with different working distances can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical system design, in particular to an infrared target simulator focusing collimation optical system and a design method thereof, which is used to meet the target simulation requirements of photoelectric detection equipment under different working temperatures and working distances. BACKGROUND

[0002] The infrared target simulator is an important part of infrared target simulation experiment. When the exit pupil of the collimation system coincides with the entrance pupil of the measured equipment, a stable infinite simulation target can be provided for the infrared detection equipment to evaluate the performance and precision of the infrared detection equipment such as infrared seeker, infrared search and tracking system, and infrared warning system. With the further improvement of the performance of the infrared detection equipment, higher requirements are put forward for the infrared target simulator. Large exit pupil aperture, large exit pupil distance, large field of view, and high transmittance have become new requirements of the infrared target simulator. In addition, more complex application scenarios also require the infrared target simulator to meet the target simulation requirements of the seeker and other photoelectric detection equipment in a wider working temperature range. In addition, the infrared target simulator should also be able to adapt to the target simulation requirements of different working distances of the seeker and other photoelectric detection equipment due to the self optical system adjustment error.

[0003] The above various requirements have greatly increased the design difficulty of the infrared target simulator, especially the optical projection system. In order to obtain excellent infrared target simulation effect, the traditional optical material matching and other methods of aberration correction and athermalization cannot meet the requirements. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides an infrared target simulator focusing collimation optical system and a design method thereof, which effectively solves the problems of large exit pupil aperture, large exit pupil distance, large field of view, high transmittance, wide temperature range, and adaptability to different measured equipment in the prior art.

[0005] The technical scheme of the present application is as follows:

[0006] The infrared target simulator focusing collimation projection optical system is composed of a telescope objective, an intermediate field lens, and a relay lens group. After the source target and background image generated by the infrared target simulator are input into the DMD, the incident light is first passed through the relay lens group and the intermediate field lens to generate a primary image of the image on the DMD, and then the primary image is collimated and projected to the entrance pupil of the measured photoelectric equipment through the telescope objective.

[0007] Further, the telescope objective is made of Ge, the intermediate field lens is made of ZnSe, and the relay lens group is composed of three lenses made of chalcogenide material IRG201-Ge-Ge.

[0008] Further, the structure parameters of the focusing collimating projection optical system of the infrared target simulator are as follows:

[0009]

[0010] Further, the focusing lens group is composed of the IRG201 in the relay lens group and the first Ge lens group, and the adjustment amount and adjustment direction of the focusing lens group are determined according to different temperatures and working distances, so as to adapt to a larger range of temperature changes and different states of photoelectric measured devices.

[0011] The design method of the focusing collimating projection optical system of the infrared target simulator comprises the following stages:

[0012] The first design stage:

[0013] Firstly, the effective light aperture of the first lens of the collimating projection optical system is calculated according to the exit pupil distance, exit pupil aperture and field angle in the design index requirements; the secondary imaging optical structure is determined, the field lens is added between the telescope group and the relay lens group, forming the optical structure composed of the far objective lens, the intermediate field lens and the relay lens group; and the image far field optical path is adopted to ensure that the chief rays of each field in the optical path are parallel to the optical axis of the system;

[0014] Secondly, the optical structure composed of the far objective lens, the intermediate field lens and the relay lens group is determined to be composed of 5 lenses, the far objective lens material is Ge, the intermediate field lens adopts ZnSe, the relay lens group adopts the three-lens group of sulfur material IRG201-Ge-Ge, and the three even aspheric surfaces are respectively on the front surface of the first lens, the rear surface of the fourth lens and the rear surface of the fifth lens from the far objective lens to the relay lens group; and the curvature radius and thickness parameters of the lenses are adjusted to correct the aberration of the optical structure and meet the design index requirements;

[0015] The second design stage:

[0016] Firstly, the thickness of the IRG201 lens is increased from 8.1 mm to 15.8 mm to solve the problem of difficult processing of the sulfur material IRG201 determined in the first design stage;

[0017] Secondly, the focusing lens group is designed in the relay lens group to solve the problems of temperature range expansion and matching with different photoelectric measured devices, and the axial position of the focusing lens group is adjusted to compensate for the system error caused by temperature changes, and the distance of the projection image of the optical system is also adjusted to adapt to different states of photoelectric measured devices.

[0018] Beneficial effects

[0019] The application provides an infrared target simulator focusing collimation projection optical system and a design method thereof.

[0020] The application realizes the design of the infrared target simulator focusing collimation projection optical system under the working temperature of 0-40 DEG C, the working wave band of 8-12 mu m, the exit pupil distance of 850 mm, the exit pupil aperture of 115 mm and the circular field of view of 8 DEG, and the working distance of the measured photoelectric equipment is 170 m to infinity in front of the exit pupil of the target simulator and 170 m to infinity behind the exit pupil.

[0021] Additional aspects and advantages of the application will be made apparent by the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and / or additional aspects and advantages of the application will become apparent and be readily understood by considering the following detailed description, including the accompanying drawings, in which:

[0023] Figure 1 Figure 1 is a collimation projection optical system structure diagram of an infrared target simulator;

[0024] Figure 2 Figure 2 is an optical path diagram of the collimation projection optical system obtained in the first stage design;

[0025] Figure 3 Figure 3 is the optical system MTF under 15 DEG C after the first stage design;

[0026] Figure 4 Figure 4 is the optical system MTF under 20 DEG C after the first stage design;

[0027] Figure 5 Figure 5 is the optical system MTF under 30 DEG C after the first stage design;

[0028] Figure 6 Figure 6 is the optical system distortion under 15 DEG C after the first stage design;

[0029] Figure 7Optical system distortion after the first stage design at 20℃;

[0030] Figure 8 Optical system distortion after the first stage design at 30℃;

[0031] Figure 9 Optical path diagram of the collimating projection optical system obtained by the second stage design;

[0032] Figure 10 System MTF of the collimating projection optical system after focusing at 0℃ obtained by the second stage design;

[0033] Figure 11 System MTF of the collimating projection optical system after focusing at 40℃ obtained by the second stage design;

[0034] Figure 12 System MTF of the collimating projection optical system after positive focusing obtained by the second stage design;

[0035] Figure 13 System distortion of the collimating projection optical system after positive focusing obtained by the second stage design;

[0036] Figure 14 System MTF of the collimating projection optical system after negative focusing obtained by the second stage design;

[0037] Figure 15 System distortion of the collimating projection optical system after negative focusing obtained by the second stage design;

[0038] Figure 16 Transmittance measured data curve. DETAILED DESCRIPTION

[0039] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and are not to be understood as limiting the present application.

[0040] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0041] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of the indicated technical features. Thus, features defined with "first", "second" or "third" can explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise explicitly and specifically limited.

[0042] The infrared target simulator generates gray-scale image video data containing long-wave infrared features of targets / backgrounds by an image generation computer, inputs the infrared DMD device through a video processing circuit and a driving circuit, adopts a black body with a large radiation temperature range and a fast temperature adjustment speed as a radiation source, uniformly irradiates the DMD device through a TIR prism, projects the infrared thermal scene generated by the DMD reflecting and modulating the incident radiation to the entrance pupil of the tested unit through a collimating projection optical system, and makes the infrared scene present on the image spot size and the radiation energy spatial distribution of the detection system to simulate the response caused by the real target and background to the detection system, so as to achieve the purpose of evaluating the performance of the tested device. Compared with the television target simulator, the long-wave infrared target simulator needs a large relative aperture, an optical aperture and a transmittance to obtain more infrared radiation. In the embodiment, the design indexes of the collimating projection optical system are shown in Table 1:

[0043] Table 1 Design indexes of the collimating projection optical system

[0044]

[0045] The above requirements of wide waveband, large exit pupil distance, large exit pupil diameter, high transmittance and wide temperature range greatly increase the difficulty of correcting the full field aberration of the collimating projection optical system in the long-wave infrared target simulator.

[0046] First stage design:

[0047] The design of the collimating projection optical system needs to meet the requirements of the waveband, field of view, energy and testing of the tested system, and also needs to consider the needs of the whole simulation system adjustment. Since the transmission type optical system is more convenient to adjust and check, the collimating projection optical system in the embodiment adopts a transmission type structure.

[0048] According to the exit pupil distance, exit pupil diameter and field of view angle in Table 1, the effective optical aperture of the first lens of the collimating projection optical system reaches 234 mm, which belongs to a large aperture optical system. Therefore, a secondary imaging optical structure is needed, a field lens is added between the telescope group and the relay lens to effectively compress the beam aperture, reduce the system weight, and reduce the relay objective group to realize the cooperation with the DMD and the light source. The specific structure is as follows: Figure 1As shown, the infrared target simulator is composed of a telescope, an intermediate field lens and a relay lens group; after the source target and background image generated by the infrared target simulator are input into the DMD, the incident light is input into the focusing collimating projection optical system, and the incident light is first projected onto the primary image of the image on the DMD through the relay lens group and the intermediate field lens, and then collimated and projected onto the entrance pupil of the measured photoelectric device through the telescope.

[0049] Moreover, for the infrared target simulator with the DMD as the image generator, the collimating projection optical system adopts a telecentric optical path in the image space to ensure that the chief rays of each field of view in the optical path are parallel to the optical axis of the system, and to match the working principle of the ±12° regulation angle of the array unit in the DMD to achieve the maximum system efficiency and improve the image uniformity obtained by the measured device.

[0050] However, since the effective aperture of the collimating projection optical system obtained according to the index requirements reaches 234mm, the large aperture brings large field curvature, astigmatism and distortion, and these off-axis aberrations will rapidly increase with the increase of the field of view, the exit pupil distance and the exit pupil diameter. Moreover, in addition to the primary aberrations and the third-order aberrations of spherical aberration, coma, astigmatism, field curvature and distortion, the high-order aberrations and chromatic aberrations to be corrected also become very large, so the optical system structure will inevitably become more complex. However, since the transmittance requirement in the system index is very high (≥75%), the number of optical elements in the optical path is limited, so aspherical surfaces are used to correct the aberrations and simplify the optical system structure.

[0051] In addition, compared with visible light materials, the refractive index temperature variation gradient of infrared optical materials is larger, and the infrared optical system is more sensitive to temperature, so in order to obtain good image quality within a certain working temperature, the athermalization technology based on optical material matching is adopted in this embodiment, the appropriate infrared optical material is selected, the lens power is calculated, and the achromatization and athermalization design is performed. Through theoretical calculation, the initial structure of the collimating projection optical system in this stage is determined, including the parameters of the material, shape and position of the lens, etc.: as shown in the figure Figure 2 As shown, the initial structure of the optical system is composed of 5 lenses, the total length of the system is 550mm from the front surface of the first lens to the image plane of the DMD, the material of the telescope is Ge, the intermediate field lens adopts ZnSe, and the relay lens group adopts the three lenses of the sulfide material IRG201-Ge-Ge. From the telescope to the relay lens group, the three even aspherical surfaces are respectively on the front surface of lens 1 (telescope), the rear surface of lens 4 and the rear surface of lens 5.

[0052] Optical design software is used to optimize the initial structure of the optical system, adjust the radius of curvature, thickness and other parameters of the lens, so that the aberration of the system is effectively corrected and meets the design requirements. In the optimization process, focus on MTF, distortion and other performance indicators to ensure that the system has good imaging quality at different temperatures. Figures 3-5 It can be seen that the full field optical transfer function MTF of the optical system at 20℃ is greater than 0.41, the full field optical transfer function MTF at 15℃ is reduced to 0.36, and the full field optical transfer function MTF at 30℃ is reduced to 0.35. From Figures 6-8 It can be seen that the full field distortion of the optical system at 15℃~30℃ is basically not affected by temperature and remains at 0.35%. Analysis shows that when the infrared target simulator works at 15℃~30℃, the imaging quality is good. The transmittance calculation formula is used to calculate the transmittance of the system, which shows that the transmittance of the optical system after the first stage design is 76.06%, which shows that the first stage has completed the design of the long-wave infrared target simulator collimating projection optical system with an exit pupil distance of 850mm, an exit pupil diameter of 115mm, an 8° field of view, a transmittance of 76.06% and an athermalization at 15℃~30℃.

[0053] Finally, after the first stage design, the structure parameters of the optical system are obtained as follows:

[0054]

[0055] The units in the table are mm, where the interval refers to the distance between the current surface and the subsequent surface, such as the front surface of the telescope objective lens interval 18mm, which means the distance between the front surface of the telescope objective lens and the rear surface of the telescope objective lens is 18mm (i.e. the thickness of the telescope objective lens), and the rear surface of the telescope objective lens interval 347mm means the distance between the rear surface of the telescope objective lens and the front surface of the field lens.

[0056] Second stage design:

[0057] For the optical system obtained after the first stage design, we found new problems in the actual engineering implementation:

[0058] (1) Sulfur material IRG201 processing problem.

[0059] The chalcogenide glass IRG201 used in the collimating projection optical system plays a good role in the optical path, but the obvious defect of the material is that the material texture is very soft. In actual trial processing, the process flow of optical cold processing of IRG201 is: first, use a diamond lathe, and then fine polish on a polishing table. Because the material is very soft, it is difficult to polish to the ideal surface shape during fine polishing, and because the material is too soft, the sample plate cannot be accurately measured during detection, resulting in that the surface shape accuracy cannot be guaranteed. Therefore, it seriously affects the imaging quality of the system, especially for large aperture and small center thickness IRG201 series chalcogenide glass lenses, which are more difficult to achieve in engineering.

[0060] (2) Temperature range expansion problem.

[0061] By Figures 3-5 Analysis shows that when the working temperature is lower than 15℃ and higher than 30℃, the MTF of the optical system gradually decreases, which is not suitable for working in the environment with large temperature difference.

[0062] (3) Matching problem with different photoelectric measuring devices.

[0063] When the target simulator is installed and adjusted on the turntable, a single photoelectric detection device is generally used as a measured sample for calibration to obtain clear image quality and other good target simulation states. In engineering practice, when different test pieces are replaced, the simulation image quality may become poor. The reason is that the optical system of different photoelectric detection devices has a small difference in focal length during factory calibration, which brings system error, so that the incident light beam is not strictly parallel light, that is, the working distance is not infinite. In addition, there are also some photoelectric detection devices with a slight difference from the nominal focal length in engineering, which will cause image blur and other problems during testing, affecting the infrared target simulation effect. This also requires the infrared target simulator to be able to fine-tune the focal length to synchronize with different states of photoelectric detection devices.

[0064] In view of the above three problems, the following corresponding solutions are adopted in the second stage design:

[0065] 1. For the processing difficulty problem of chalcogenide material IRG201, the method of increasing the ratio of lens center thickness to aperture is adopted, that is, the thickness of IRG201 lens is increased from 8.1mm to 15.8mm, and the aperture is reduced to 33mm, so as to ensure that a stable and good surface shape is obtained in the fine polishing process of optical cold processing.

[0066] 2. To address the issues of temperature range expansion and compatibility with different optoelectronic devices under test (DUTs), a focusing lens group is designed within the relay lens assembly. By fine-tuning the axial position of this focusing lens group, systematic errors caused by temperature variations are compensated. Simultaneously, the distance of the projected image from the optical system can be adjusted to adapt to DUTs in different states, achieving the goal of simulating precise focusing across different batches of DUTs. The design results are as follows: Figure 9 As shown, with the lens material order, quantity, and aspherical surface position remaining unchanged, the focusing lens group is designed to achieve the following: Figure 9 The area within the dashed box contains a focusing lens group composed of the IRG201 relay lens and the first Ge lens. The adjustment range and direction of this focusing lens group are determined based on different temperature and working distance requirements to accommodate a wider range of temperature variations and different states of the photoelectric measurement equipment. Structurally, a cam-based focusing method is used. Rotating the outer sleeve via a handwheel causes the focusing lens group to slide axially, achieving fine-tuning of the focal length.

[0067] The structural parameters of each component of the final designed infrared target simulator collimating projection optical system are as follows:

[0068]

[0069] The collimating projection optical system expands its operating temperature range and meets the target simulation requirements of different batches of seekers and other optoelectronic test equipment at different working distances by adjusting the focus as follows:

[0070] Focusing to extend the operating temperature range:

[0071] System errors caused by temperature variations are compensated by adjusting the focusing lens group of the collimating projection optical system of the infrared target simulator. At an operating temperature of 0℃, the corresponding adjustment amount of the focusing lens group is 2.18mm, with the side closer to the DMD being positive. The full-field optical transfer function (MTF) of the optical system is as follows: Figure 10 At an operating temperature of 40℃, the corresponding adjustment amount of the focusing lens group is -1.95mm, and the full-field optical transfer function (MTF) of the optical system is as follows: Figure 11 By adjusting the focusing lens group of the collimating projection optics system of the infrared target simulator, the optical transfer function (MTF) of the target simulator is greater than 0.35 across the entire field of view within the operating temperature range of 0℃ to 40℃, thus achieving a good simulation state.

[0072] Focusing is adjusted to meet the target simulation requirements of different batches of seekers and other optoelectronic test equipment at different working distances:

[0073] 1) Positive adjustment amount. By adjusting the focusing lens group of the collimating projection optical system of the infrared target simulator, the focal length of the system is finely adjusted so that the working distance of the photoelectric system under test can be clearly imaged from infinity to -170m from the entrance pupil. The adjustment amount is 0.36mm, and the side closer to the DMD is positive. Figure 12The corresponding MTF curve is shown in Fig. 6, and the corresponding system distortion curve is shown in Fig. 7. Figure 13 It can be seen that the optical system after focusing reaches good image quality, and the full-field MTF at 36.5 lp / mm is greater than 0.34, and the full-field distortion is 0.33%, and the image quality meets the requirements of the simulator optical performance. Figures 12-13

[0074] 2) negative adjustment amount, by adjusting the collimating projection optical system focusing lens group of the infrared target simulator, the system focal length is fine-tuned, so that the measured photoelectric system is clearly imaged in the working distance from infinity to the distance from the entrance pupil + 170m, and the adjustment amount is-1.28mm. Figure 14 The corresponding MTF curve is shown in Fig. 6, and the corresponding system distortion curve is shown in Fig. 7. Figure 15 It can be seen that the optical system after focusing reaches good image quality, and the full-field MTF at 36.5 lp / mm is greater than 0.33, and the full-field distortion is 0.36%, and the image quality meets the requirements of the simulator optical performance. Figures 14-15

[0075] Figure 16 The collimating projection optical system transmittance measurement curve is shown in Fig. 8, wherein the blackbody temperature is 100℃, the blackbody radiation brightness distribution at 8-12um is the red curve, and after passing through the projection optical system, the system radiation brightness distribution at 8-12um is the blue curve, and the system transmittance is calculated to be 75.59% according to the corresponding data, which is higher than the index requirement.

[0076] The collimating projection optical system proposed in the embodiment uses the matching mode of positive and negative optical power, Abbe number and thermal defocusing coefficient, and by using a field lens in the secondary imaging path and introducing aspherical surface and chalcogenide glass IRG201, only 5 lenses are used to realize the design of the infrared target simulator collimating projection optical system with large exit pupil distance, large exit pupil diameter, large field of view, high transmittance and athermalization, which realizes achromatism and athermalization while ensuring high transmittance.

[0077] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and spirit of the present application within the scope of the present application.​​

Claims

1. A focusing, collimating, and projection optical system for an infrared target simulator, comprising a telescope objective lens, an intermediate field lens, and a relay lens group; characterized in that: After the source target and background images generated by the infrared target simulator are input into the DMD, they are incident on the focusing and collimating projection optical system through the DMD. The incident light in the focusing and collimating projection optical system first generates a primary image on the DMD through the relay lens group and the intermediate field lens, and then collimates and projects the primary image plane onto the entrance pupil of the photoelectric device under test through the telescope objective lens.

2. The infrared target simulator focusing, collimating, and projection optical system according to claim 1, characterized in that: The objective lens is made of Ge, the intermediate field lens is made of ZnSe, and the relay lens group consists of three lenses made of chalcogenide material IRG201-Ge-Ge.

3. The infrared target simulator focusing, collimating, and projection optical system according to claim 1, characterized in that: The structural parameters of each component of the infrared target simulator focusing collimating projection optical system are as follows: 。 4. The infrared target simulator focusing, collimating, and projection optical system according to claim 3, characterized in that: The focusing lens group consists of IRG201 in the relay lens group and the first Ge lens. The adjustment amount and direction of the focusing lens group are determined according to the requirements of different temperatures and working distances, so as to adapt to a wider range of temperature changes and photoelectric devices under test in different states.

5. The infrared target simulator focusing, collimating, and projection optical system according to claim 1, characterized in that: The design specifications for the focusing and collimating projection optical system are as follows: 。 6. The design method of the infrared target simulator focusing, collimating, and projection optical system according to claim 5, characterized in that: Includes the following stages: First design phase: First, the effective aperture of the first lens of the collimating projection optical system is calculated based on the exit pupil distance, exit pupil diameter, and field of view required by the design specifications. Then, a secondary imaging optical structure is adopted, and a field lens is added between the telescope group and the relay lens group to form an optical structure consisting of a distant objective lens, an intermediate field lens, and a relay lens group. Furthermore, an image-side telecentric optical path is adopted to ensure that the principal rays of each field of view in the optical path are parallel to the optical axis of the system. Secondly, based on the distortion and transmittance requirements in the design specifications, the optical structure consisting of a telephoto objective, an intermediate field lens, and a relay lens group is determined to be composed of 5 lenses. The telephoto objective is made of Ge, the intermediate field lens is made of ZnSe, and the relay lens group is composed of 3 lenses made of chalcogenide material IRG201-Ge-Ge. Furthermore, from the telephoto objective to the relay lens group, the three even-order aspherical surfaces are located on the front surface of the first lens, the rear surface of the fourth lens, and the rear surface of the fifth lens, respectively. By adjusting the curvature radius and thickness parameters of the lenses, the aberrations of the optical structure are corrected to meet the design specifications. Second design phase: First, to address the difficulty in processing the chalcogenide material IRG201 identified in the first design phase, the thickness of the IRG201 lens was increased from 8.1 mm to 15.8 mm; Secondly, to address the issues of expanding the temperature range and matching with different optoelectronic devices under test, a focusing lens group is designed within the relay lens group. By finely adjusting the axial position of the focusing lens group, the system error caused by temperature changes can be compensated. At the same time, the distance of the image projected by the optical system can also be adjusted to adapt to optoelectronic devices under test in different states.

7. The design method of the infrared target simulator focusing, collimating, and projection optical system according to claim 5, characterized in that: After the first phase of design, the structural parameters of the optical system obtained are as follows: 。

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