10-time medium-wave infrared microscope applied to high and low temperature function transfer instrument

Abstract

The invention discloses a 10-time medium-wave infrared microscope applied to a high and low temperature transfer instrument. The 10-time medium-wave infrared microscope comprises a high and low temperature box exit window, a front imaging system and a rear imaging system, an object space imaging light beam is parallel light after sequentially passing through a first high-low temperature box emergent window, a second high-low temperature box emergent window, a first front group lens, a second front group lens, a third front group lens, a fourth front group lens and a fifth front group lens, and an exit pupil of a front group is matched with an entrance pupil of a rear group. And the image is imaged on the focal plane of the area array detector through the first rear group lens, the second rear group lens, the third rear group lens, the fourth rear group lens and the fifth rear group lens. According to the invention, through matching of silicon and germanium materials and use of the aspheric surface and the diffraction surface of the lens, aberration correction of a medium-wave infrared band is realized. According to the microscope, the object space numerical aperture is 0.35, the working wave band is 3-5 microns, the front group focal length is 20 mm, the rear group focal length is 200 mm, and the amplification factor is 10 times.

Description

Technical Field

[0001] The invention relates to the technical field of infrared systems, and in particular to a 10x medium-wave infrared microscope used in a high-low temperature transmission instrument, which is suitable for high-low temperature transmission test of a medium-wave infrared lens with an F number of more than 1.5. Background Art

[0002] The optical transfer function is a comprehensive expression of the image quality of the optical system and is an important indicator for evaluating the image quality of the optical system. However, under high and low temperature environments, due to temperature changes, the refractive index of the lens in the optical system will change, the structural parts will expand and contract, and the spacing between the lenses will change, which will cause the focal length of the optical system to change, the image plane will drift, and the image quality will deteriorate. Therefore, testing the optical transfer function of the optical system under high and low temperature environments can evaluate the image quality of the system under high and low temperature conditions. The methods for the high and low temperature transfer function instrument to test the medium-wave infrared system are mainly scanning method and image analysis method. The scanning method uses a point source detector as the receiver of the test system, and the test steps are cumbersome and inefficient; the image analysis method uses an array detector as the receiver of the test system, equipped with a micro-magnification system, which can display star point images on the display, which helps to provide intuitive image quality analysis basis for assembly and inspection personnel, and the test efficiency is higher.

[0003] When using a high and low temperature transmitter to test a medium-wave infrared lens, the main function of the medium-wave infrared microscope is to conjugate the focal plane of the lens under test with the focal plane of the area array detector, and to magnify the image formed by the focal plane of the lens under test onto the focal plane of the area array detector, thereby achieving image magnification and transmission, which is beneficial to image recognition and transmitter function solution. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a 10x medium wave infrared microscope applied to a high and low temperature transmitter in view of the defects in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] The present invention provides a 10x medium wave infrared microscope applied to a high and low temperature transmitter, comprising: a high and low temperature box exit window, a front imaging system and a rear imaging system; wherein:

[0007] The high and low temperature box exit window includes a first high and low temperature box exit window and a second high and low temperature box exit window; the front group imaging system includes a first front group lens, a second front group lens, a third front group lens, a fourth front group lens and a fifth front group lens; the rear group imaging system includes a first rear group lens, a second rear group lens, a third rear group lens, a fourth rear group lens and a fifth rear group lens;

[0008] The object-side imaging beam passes through the first high-temperature and low-temperature box exit window, the second high-temperature and low-temperature box exit window, the first front lens group, the second front lens group, the third front lens group, the fourth front lens group and the fifth front lens group in sequence and becomes parallel light. The exit pupil of the front lens group matches the entrance pupil of the rear lens group, and then passes through the first rear lens group, the second rear lens group, the third rear lens group, the fourth rear lens group and the fifth rear lens group to form an image on the focal plane of the area array detector.

[0009] Furthermore, the front group focal length of the medium-wave infrared microscope of the present invention is 20 mm, and the rear group focal length is 200 mm, so as to achieve aberration correction of the medium-wave infrared 10x microscope.

[0010] Furthermore, the materials of the lenses of the present invention are single crystal silicon and single crystal germanium, the incident direction of light is the object side, that is, the focal plane of the test lens, and the emitting direction of light is the image side, that is, the focal plane of the area array detector.

[0011] Furthermore, the first high and low temperature box exit window and the second high and low temperature box exit window of the present invention are both sapphire plane light windows; the first front lens group is a meniscus germanium negative lens convex to the image side, the second front lens group is a plano-convex silicon positive lens convex to the image side, the third front lens group is a plano-concave germanium negative lens concave to the object side, the fourth front lens group is a bi-convex silicon positive lens, and the fifth front lens group is a meniscus germanium negative lens convex to the object side; the first rear lens group is a plano-convex silicon positive lens convex to the object side, the second rear lens group is a bi-concave germanium positive lens, the third rear lens group is a meniscus germanium negative lens convex to the object side, the fourth rear lens group is a meniscus germanium negative lens convex to the object side, and the fifth rear lens group is a meniscus silicon positive lens convex to the image side.

[0012] Furthermore, the lens form of the medium-wave infrared microscope of the present invention adopts a front group and a rear group designed independently, and the rear group adopts a secondary imaging structure to ensure that the entrance and exit pupils of the front and rear groups are matched.

[0013] Furthermore, the lens optical element of the medium-wave infrared microscope of the present invention adopts aspherical surfaces and diffractive surfaces, the first surface of the first front lens group and the second surface of the second rear lens group are aspherical surfaces, and the second surface of the fifth front lens group is a diffractive surface.

[0014] Furthermore, the first high and low temperature box exit window and the second high and low temperature box exit window of the present invention are high and low temperature box exit windows made of sapphire material, which can be heat-insulated and not frosted in high and low temperature environments. The windows are in the converging light path, introducing astigmatism, which is brought into the design software for optimization and is used to test the transfer function of the lens under test at high and low temperatures.

[0015] Furthermore, the lens numerical aperture of the medium-wave infrared microscope of the present invention reaches 0.35, which is suitable for performing transfer function testing on medium-wave infrared lenses with an F number of 1.5 or above.

[0016] Furthermore, the working band of the medium-wave infrared microscope of the present invention is 3 μm to 5 μm.

[0017] Furthermore, the medium-wave infrared microscope of the present invention is suitable for a medium-wave refrigerated area array detector with a pixel number of 640×512 and a pixel size of 15 microns.

[0018] The beneficial effects produced by the present invention are:

[0019] 1. Two high and low temperature box exit windows made of sapphire are placed between the front lens group and the lens under test, which can insulate and prevent frost in high and low temperature environments. Since the window is in the converging light path, astigmatism will be introduced, which is brought into the design software for optimization, and the transfer function of the lens under test can be tested at high and low temperatures;

[0020] 2. The numerical aperture of the lens reaches 0.35, which can perform transmission function test on medium-wave infrared lenses with F number 1.5 and above;

[0021] 3. The focal length of the front lens group is 20mm, the focal length of the rear lens group is 200mm, and the magnification ratio reaches 10 times. It can magnify the image formed on the focal plane of the lens under test to the focal plane of the array detector, thereby realizing image magnification and transmission;

[0022] 4. The lens adopts a separate design for the front group and the rear group. The rear group adopts a secondary imaging structure to ensure the matching of the front and rear group entrance and exit pupils, reduce the size of the system, strictly control the image quality of the front and rear groups, and can perform transmission function tests on the front and rear groups separately, reducing the difficulty of lens installation and detection;

[0023] 5. The lens band design range is 3μm~5μm, which can be applied to the test of most medium-wave infrared optical systems.

[0024] In summary, the 10x medium-wave infrared microscope applied to the high and low temperature transmitter of the present invention has the characteristics of large numerical aperture, high magnification, high imaging quality and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 is a schematic diagram of an optical system according to an embodiment of the present invention;

[0027] Figure 2 is a two-dimensional diagram of an optical system according to an embodiment of the present invention;

[0028] Figure 3 This is the MTF diagram of the optical system front group imaging system of the embodiment of the present invention when 12lp / mm;

[0029] Figure 4 This is the MTF diagram of the optical system after the imaging system of the embodiment of the present invention when 12lp / mm;

[0030] Figure 5 This is the MTF diagram of the entire optical system of the embodiment of the present invention at 12lp / mm;

[0031] Figure 6 is a point arrangement diagram of an imaging system of the optical system front group according to an embodiment of the present invention;

[0032] Figure 7 is a point arrangement diagram of the imaging system of the optical system rear group according to an embodiment of the present invention;

[0033] Figure 8 1 is a point diagram of the entire optical system according to an embodiment of the present invention.

[0034] In the figure, 1-the exit window of the first high and low temperature box, 2-the exit window of the second high and low temperature box, 3-the first front lens group, 4-the second front lens group, 5-the third front lens group, 6-the fourth front lens group, 7-the fifth front lens group, 8-the first rear lens group, 9-the second rear lens group, 10-the third rear lens group, 11-the fourth rear lens group, 12-the fifth rear lens group. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Example 1

[0037] like Figure 1-Figure 2 As shown, the 10x medium wave infrared microscope applied to the high and low temperature transmitter according to the embodiment of the present invention comprises a high and low temperature box exit window, a front group and a rear group, wherein:

[0038] The high and low temperature box exit window includes a first high and low temperature box exit window 1 and a second high and low temperature box exit window 2, the front group includes a first front lens group 3, a second front lens group 4, a third front lens group 5, a fourth front lens group 6 and a fifth front lens group 7, a total of five lenses, and the rear group includes a first rear lens group 8, a second rear lens group 9, a third rear lens group 10, a fourth rear lens group 11 and a fifth rear lens group 12, a total of five lenses.

[0039] The object side imaging light beam passes through the first high and low temperature box exit window 1, the second high and low temperature box exit window 2, the first front lens group 3, the second front lens group 4, the third front lens group 5, the fourth front lens group 6 and the fifth front lens group 7 in sequence and becomes parallel light, and then passes through the first rear lens group 8, the second rear lens group 9, the third rear lens group 10, the fourth rear lens group 11 and the fifth rear lens group 12 to form an image on the focal plane of the area array detector.

[0040] In a preferred embodiment of the present invention, through the use of material matching, aspherical surfaces and diffraction surfaces, the microscope object numerical aperture is 0.35, the working band is 3μm~5μm, the front group focal length is 20mm, and the rear group focal length is 200mm, so as to achieve aberration correction of the medium-wave infrared 10x microscope.

[0041] The lens of the embodiment of the present invention adopts a front group and a rear group that are designed to be separated, and the rear group adopts a secondary imaging structure, which strictly ensures that the front and rear groups have pupil matching and reduces the size of the system. Both the front and rear groups of the lens have good image quality and can be tested separately, which reduces the difficulty of installation and detection.

[0042] Two high and low temperature box exit windows made of sapphire are placed between the front lens group and the lens under test. They can insulate and prevent frost in high and low temperature environments. The windows are in the converging light path, which will introduce astigmatism. When optimized in the design software, the transfer function of the lens under test can be tested at high and low temperatures.

[0043] In a preferred embodiment of the present invention, the numerical aperture of the lens reaches 0.35, which is suitable for the transfer function test of the medium-wave infrared lens under test with an F number of 1.5 or above, and is suitable for the medium-wave cooled area array detector with a pixel number of 640×512 and a pixel size of 15 microns.

[0044] In a preferred embodiment of the present invention, the materials of the lens are conventional medium-wave infrared materials, single crystal silicon and single crystal germanium, the incident direction of the light is the object side, that is, the focal plane of the test lens, and the emitting direction of the light is the image side, that is, the focal plane of the array detector.

[0045] The first high and low temperature box exit window 1 and the second high and low temperature box exit window 2 are both sapphire plane light windows; the first front lens group 3 is a meniscus germanium negative lens convex to the image side, the second front lens group 4 is a plano-convex silicon positive lens convex to the image side, the third front lens group 5 is a plano-concave germanium negative lens concave to the object side, the fourth front lens group 6 is a bi-convex silicon positive lens, and the fifth front lens group 7 is a meniscus germanium negative lens convex to the object side; the first rear lens group 8 is a plano-convex silicon positive lens convex to the object side, the second rear lens group 9 is a bi-concave germanium positive lens, the third rear lens group 10 is a meniscus germanium negative lens convex to the object side, the fourth rear lens group 11 is a meniscus germanium negative lens convex to the object side, and the fifth rear lens group 12 is a meniscus silicon positive lens convex to the image side.

[0046] In order to effectively realize aberration correction and reduce the complexity of the system, some optical elements of the lens adopt aspherical surfaces and diffraction surfaces to improve the imaging quality of the system. The first surface of the first front lens group 3 and the second surface of the second rear lens group 9 are aspherical surfaces, and the second surface of the fifth front lens group 7 is a diffraction surface.

[0047] Example 2

[0048] according to Figure 1 As shown in the schematic diagram of the optical system, the present invention discloses a 10x medium-wave infrared microscope applied to a high and low temperature transmitter, with a working band of 3μm to 5μm, a magnification of 10×, and an object space numerical aperture of 0.35.

[0049] The object-side imaging light beam passes through the first high-temperature and low-temperature box exit window 1, the second high-temperature and low-temperature box exit window 2, the first front lens group 3, the second front lens group 4, the third front lens group 5, the fourth front lens group 6 and the fifth front lens group 7 in sequence and becomes parallel light, and then passes through the first rear lens group 8, the second rear lens group 9, the third rear lens group 10, the fourth rear lens group 11 and the fifth rear lens group 12 to converge on the focal plane of the area array detector. Through the use of material matching, aspherical surfaces and diffraction surfaces, the aberration correction of the medium-wave infrared 10x microscope is achieved.

[0050] Specifically, the optical system of the present invention comprises 10 lenses, two sapphire temperature box protection windows, the first high and low temperature box exit window 1 and the second high and low temperature box exit window 2 are both sapphire plane light windows; the first front lens group 3 is a meniscus germanium negative lens convex to the image side, the first surface is aspherical, and the aspheric coefficient is A=-1.8066×10 -6 , B=7.3696×10 -8 The second front lens group 4 is a plano-convex silicon positive lens with a convex surface on the image side, the third front lens group 5 is a plano-concave germanium negative lens with a concave surface on the object side, the fourth front lens group 6 is a biconvex silicon positive lens, the fifth front lens group 7 is a meniscus germanium negative lens with a convex surface on the object side, the second surface is a diffraction surface, and the diffraction surface coefficients C1 = 0.001, C2 = 8.8384×10 -7 The first rear lens group 8 is a plano-convex silicon positive lens with the convex surface facing the object side, and the second rear lens group 9 is a biconcave germanium positive lens, the second surface is aspherical, and the aspherical coefficient is A = -3.7172×10 -6 , B=4.1078×10 -8 , C = -1.8084 × 10 -10 The third rear lens group 10 is a meniscus germanium negative lens convex to the object side, the fourth rear lens group 11 is a meniscus germanium negative lens convex to the object side, and the fifth rear lens group 12 is a meniscus silicon positive lens convex to the image side.

[0051] In a preferred embodiment of the present invention, the lens adopts a front group and a rear group that are designed separately, and the rear group adopts a secondary imaging structure to ensure that the front and rear groups have matching entrance and exit pupils, strictly control the image quality of the front and rear groups, and can perform transmission function tests on the front and rear groups separately, thereby reducing the difficulty of lens assembly and testing;

[0052] In a preferred embodiment of the present invention, two high and low temperature box exit windows of sapphire material with a thickness of 4 mm and a spacing of 6 mm are placed between the front lens group and the lens under test, so that the transfer function of the lens under test at high and low temperatures can be tested;

[0053] The focal length of the front lens group is 20mm, the focal length of the rear lens group is 200mm, and the magnification ratio reaches 10 times. It can magnify the image formed on the focal plane of the lens under test to the focal plane of the array detector, thereby realizing image magnification and transmission;

[0054] The numerical aperture of the lens reaches 0.35, which can perform transmission function test on medium-wave infrared lenses with F number of 1.5 and above;

[0055] The maximum diameter of the lens contained in the lens does not exceed 30mm, the size is small and the structure is compact;

[0056] Along the optical axis, the distance between the focal plane of the lens under test and the exit window of the first high and low temperature box is 4 mm, the distance between the exit window of the second high and low temperature box and the first front lens group is 4 mm, and the distance between the fifth rear lens group and the focal plane of the area array detector is 28.25 mm.

[0057] like Figure 3-Figure 8 As shown, the MTF diagram of the front imaging system of the optical system at 12lp / mm; the MTF diagram of the rear imaging system at 12lp / mm; the MTF diagram of the entire optical system at 12lp / mm; the spot diagram of the front imaging system; the spot diagram of the rear imaging system; the spot diagram of the entire optical system. It can be seen from the above diagrams that the present invention has the characteristics of large numerical aperture, high magnification, high imaging quality, etc.

[0058] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0059] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A 10x medium wave infrared microscope used in a high and low temperature transmitter, characterized in that: include: High and low temperature chamber exit window, front imaging system and rear imaging system; wherein: The high and low temperature box exit window includes a first high and low temperature box exit window and a second high and low temperature box exit window; the front group imaging system includes a first front group lens, a second front group lens, a third front group lens, a fourth front group lens and a fifth front group lens; the rear group imaging system includes a first rear group lens, a second rear group lens, a third rear group lens, a fourth rear group lens and a fifth rear group lens; The object-side imaging beam passes through the first high-temperature and low-temperature box exit window, the second high-temperature and low-temperature box exit window, the first front lens group, the second front lens group, the third front lens group, the fourth front lens group and the fifth front lens group in sequence and becomes parallel light. The exit pupil of the front lens group matches the entrance pupil of the rear lens group, and then passes through the first rear lens group, the second rear lens group, the third rear lens group, the fourth rear lens group and the fifth rear lens group to form an image on the focal plane of the area array detector.

2. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The front group focal length of the medium-wave infrared microscope is 20 mm, and the rear group focal length is 200 mm, so as to realize the aberration correction of the medium-wave infrared 10x microscope.

3. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The materials of the lenses are single crystal silicon and single crystal germanium. The incident direction of the light is the object side, that is, the focal plane of the test lens, and the emitting direction of the light is the image side, that is, the focal plane of the array detector.

4. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The first high and low temperature box exit window and the second high and low temperature box exit window are both sapphire plane light windows; the first front lens group is a meniscus germanium negative lens convex to the image side, the second front lens group is a plano-convex silicon positive lens convex to the image side, the third front lens group is a plano-concave germanium negative lens concave to the object side, the fourth front lens group is a bi-convex silicon positive lens, and the fifth front lens group is a meniscus germanium negative lens convex to the object side; the first rear lens group is a plano-convex silicon positive lens convex to the object side, the second rear lens group is a bi-concave germanium positive lens, the third rear lens group is a meniscus germanium negative lens convex to the object side, the fourth rear lens group is a meniscus germanium negative lens convex to the object side, and the fifth rear lens group is a meniscus silicon positive lens convex to the image side.

5. The 10x medium wave infrared microscope used for high and low temperature transmitter according to claim 1, characterized in that: The lens form of the medium-wave infrared microscope adopts a front group and a rear group that are designed to be independent and separate, and the rear group adopts a secondary imaging structure to ensure that the front and rear groups have matching entrance and exit pupils.

6. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The lens optical element of the medium-wave infrared microscope adopts an aspherical surface and a diffractive surface. The first surface of the first front lens group and the second surface of the second rear lens group are respectively aspherical surfaces, and the second surface of the fifth front lens group is a diffractive surface.

7. The 10x medium wave infrared microscope used for high and low temperature transmitter according to claim 1, characterized in that: The first high and low temperature box exit window and the second high and low temperature box exit window are high and low temperature box exit windows made of sapphire material, which can insulate and not frost in high and low temperature environments. The windows are in the converging light path, introducing astigmatism, which is brought into the design software for optimization and is used to test the transfer function of the lens under test at high and low temperatures.

8. The 10x medium wave infrared microscope used for high and low temperature transmitter according to claim 1, characterized in that: The lens numerical aperture of the medium-wave infrared microscope reaches 0.35, and is suitable for performing transmission function tests on medium-wave infrared lenses with an F number of 1.5 or above.

9. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The working band of the medium-wave infrared microscope is 3 μm to 5 μm.

10. The 10x medium wave infrared microscope used for the high and low temperature transmitter according to claim 1, characterized in that: The medium-wave infrared microscope is suitable for a medium-wave refrigerated array detector with a pixel number of 640×512 and a pixel size of 15 microns.

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