Long-wave infrared microscopic imaging lens for optical transfer function measuring instrument

Abstract

The invention relates to a long-wave infrared microscopic imaging lens for an optical transfer function measuring instrument, and relates to the technical field of optical testing. The long-wave infrared microscopic imaging lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along a light path propagation direction, and an aperture diaphragm is arranged on the incident plane of the fifth lens. The long-wave infrared microscopic imaging lens for the optical transfer function measuring instrument is suitable for long-wave microscopic imaging and is excellent in imaging performance; tolerance capacity is loose, and processing and adjustment are easy; the testing efficiency is high, the processing cost is low, and the practical application value is very high.

Description

Technical Field

[0001] The invention relates to the field of optical testing technology, and in particular to a long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument. Background Art

[0002] The application areas of infrared optical lenses include:

[0003] 1. Security monitoring field

[0004] At night or in low light conditions, long-wave infrared lenses can produce clear images, effectively monitor the surveillance area, and promptly detect potential security threats, such as theft and illegal intrusion, and are an important part of the security monitoring system. Long-wave infrared thermal imagers are highly concealed, have a low false alarm rate, and can be in operation 24 hours a day, which is of great significance for the security of important facilities, public places, borders and other areas.

[0005] 2. Military field

[0006] It can be used for military reconnaissance and target tracking. It can detect enemy targets at night, in bad weather and in complex terrain conditions, obtain the target's thermal radiation information, and help the military accurately identify and locate targets.

[0007] 3. Medical field

[0008] Long-wave infrared imaging technology can be used for body temperature detection, especially during the epidemic prevention and control period. It can quickly and accurately measure human body temperature and plays an important role in screening patients with fever.

[0009] 4. Industrial field

[0010] Used for temperature detection and fault diagnosis of industrial equipment, it can detect the temperature distribution of equipment, promptly discover abnormal conditions such as overheating and overcooling of equipment, and predict potential failures of equipment so as to carry out maintenance and repairs in advance and reduce the risk of equipment damage and production shutdown.

[0011] 5. Firefighting and rescue field

[0012] Long-wave infrared lenses have strong penetrating power. At the fire scene, they can penetrate smoke, help firefighters quickly find the source of the fire, assess the spread of the fire, and provide important information support for fire fighting and rescue work.

[0013] 6. Agriculture

[0014] It can be used to monitor the growth of crops. By detecting the temperature difference of crops, it can determine the growth status, moisture content and the presence of pests and diseases, and provide a basis for decision-making in agricultural production. It can also be used to monitor environmental parameters such as soil moisture, helping farmers to irrigate rationally and improve agricultural production efficiency.

[0015] 7. Scientific research

[0016] In laboratory experiments, it can be applied to infrared spectroscopy analysis, chemical reaction mechanism research, material performance characterization, and biomolecule detection. For example, the key chemical information of various compounds can be analyzed and characterized to achieve accurate identification and analysis of chemical substances.

[0017] 8. Transportation

[0018] For the vehicle's autonomous driving system, the long-wave infrared lens can help the vehicle identify pedestrians, animals and other objects on the road, as well as detect the vehicle's own temperature conditions to ensure driving safety.

[0019] For the long-wave infrared lenses in the above application fields, the detection of imaging quality and lens focal length and other parameters is crucial. The optical transfer function measuring instrument is a key device for evaluating the imaging quality of the lenses in the above application fields. The optical transfer function measuring instrument can measure the transfer function of the long-wave infrared lens at different spatial frequencies and objectively evaluate the image quality of the infrared optical lens. It is suitable for the installation and inspection stages of the long-wave infrared optical lens and has universal applicability.

[0020] The optical transfer function measuring instrument includes a target generator, a collimator, an image analyzer, etc. Among them, the long-wave microscopic imaging lens is an important part of the image analyzer, and its designed imaging result is very important for the use of the entire optical transfer function measuring instrument. However, the existing long-wave infrared optical lens transfer function test equipment needs to be imported from abroad, and the supporting equipment requires high funds. Summary of the invention

[0021] The present invention aims to solve the technical problems in the prior art that long-wave infrared optical lens transmission function test equipment needs to be imported from abroad and the supporting equipment requires high funds, and provides a long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument.

[0022] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0023] A long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument comprises: a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along the propagation direction of an optical path; an aperture stop is arranged on the incident surface of the fifth lens;

[0024] The radius of curvature of the incident surface of the first lens is -15.618±0.01mm, and the radius of curvature of the exit surface of the first lens is -13.511±0.01mm;

[0025] The radius of curvature of the incident surface of the second lens is -19.722±0.01mm, and the radius of curvature of the exit surface of the second lens is -41.739±0.01mm;

[0026] The radius of curvature of the incident surface of the third lens is -24.950±0.01mm, and the radius of curvature of the exit surface of the third lens is -21.286±0.01mm;

[0027] The curvature radius of the incident surface of the fourth lens is -44.781±0.01 mm, and the curvature radius of the exit surface of the fourth lens is -29.374±0.01 mm;

[0028] The radius of curvature of the incident surface of the fifth lens is 195.308±0.01 mm, and the radius of curvature of the exit surface of the fifth lens is 284.891±0.01 mm.

[0029] In the above technical solution, the refractive indexes of the materials of the first lens, the third lens and the fifth lens are 4.0049226185 to 4.0023352871 respectively; the refractive indexes of the materials of the second lens and the fourth lens are 2.4172825199 to 2.3928100567 respectively.

[0030] In the above technical solution, the materials of the first lens, the third lens and the fifth lens are respectively germanium; the materials of the second lens and the fourth lens are respectively zinc selenide.

[0031] In the above technical solution, the object distance is 5.066±0.01mm; the center interval between the first lens and the second lens is 14.74±0.01mm; the center interval between the second lens and the third lens is 0.75±0.01mm; the center interval between the third lens and the fourth lens is 0.02±0.01mm; the center interval between the fourth lens and the fifth lens is 10.0±0.01mm; and the center interval between the fifth lens and the image plane is 196.927±1mm.

[0032] In the above technical solution, the center thickness of the first lens is 3.0±0.01mm; the center thickness of the second lens is 2.7±0.01mm; the center thickness of the third lens is 2.7±0.01mm; the center thickness of the fourth lens is 3.0±0.01mm; and the center thickness of the fifth lens is 4.0±0.01mm.

[0033] In the above technical solution, the numerical aperture is 0.5.

[0034] In the above technical solution, the wavelength range is 8 μm to 12 μm.

[0035] In the above technical solution, the magnification is 10 times.

[0036] In the above technical solution, the object height is 1 mm.

[0037] The present invention has the following beneficial effects:

[0038] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention is suitable for long-wave microscopic imaging and has excellent imaging performance; it has loose tolerance capacity and is easy to process and adjust; it has high testing efficiency and low processing cost and has high practical application value.

[0039] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention adopts matching of positive and negative optical powers of multiple lenses to correct spherical aberration based on aberration theory; selects appropriate lens materials, curvature radii and spacing to correct positional chromatic aberration; designs the imaging lens to have an imaging quality close to the diffraction limit; and can meet the use requirements of the optical transmission function measuring instrument.

[0040] By using the long-wave infrared microscopic imaging lens for an optical transfer function measuring instrument of the present invention, the self-developed optical transfer function measuring instrument can reach the accuracy of the imported f4000 type equipment, and can save a lot of costs for purchasing imported equipment for domestic purchasing units. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0042] Figure 1 The optical design diagram of the long-wave infrared microscopic imaging lens used in the optical transmission function measuring instrument of the present invention is shown in FIG.

[0043] Figure 2 The figure is a schematic diagram of the diffuse spot of the long-wave infrared microscopic imaging lens used for the optical transmission function measuring instrument of the present invention.

[0044] Figure 3 The figure is a schematic diagram of the field curvature and distortion of the long-wave infrared microscopic imaging lens used in the optical transmission function measuring instrument of the present invention.

[0045] Figure 4 It is a schematic diagram of an optical transfer function curve of a long-wave infrared microscopic imaging lens used in an optical transfer function measuring instrument of the present invention. DETAILED DESCRIPTION

[0046] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention comprises: a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the propagation direction of the optical path; the first lens is a concave-convex positive lens, the second lens is a concave-convex negative lens, the third lens is a concave-convex positive lens, the fourth lens is a concave-convex positive lens, and the fifth lens is a convex-concave positive lens. The first four lenses together form the objective lens of the long-wave infrared microscopic imaging lens, and the fifth lens is the rear tube lens. There is parallel light between the objective lens and the tube lens, and when in use, the tube lens and the imaging device at the rear image plane can be assembled and adjusted, and then the front objective lens is installed.

[0047] The aperture diaphragm is placed on the incident surface of the fifth lens. The aperture diaphragm determines the entrance pupil diameter and numerical aperture of the system. The size of the image formed by the aperture diaphragm in object space is the entrance pupil diameter, and the size of the image formed by the image aperture is the exit pupil diameter. The aperture diaphragm is placed on the fifth lens, so that the diameter of the light beam entering the imaging device can be determined by the rear end tube lens.

[0048] The object to be measured is located 5.066 mm in front of the long-wave infrared microscopic imaging lens. The long-wave infrared imaging device is located on the image plane. The numerical aperture of the long-wave infrared microscopic imaging lens is 0.5 and the magnification is 10 times.

[0049] The long-wave infrared microscopic imaging lens for the optical transfer function measuring instrument of the present invention is a long-wave infrared achromatic optical imaging lens with a wavelength range of 8 μm to 12 μm. The long-wave infrared imaging device receives long-wave spectrum signals, and the optical transfer function of the measured lens is obtained by analyzing and calculating the optical signals.

[0050] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention adopts two materials with different dispersion coefficients, the refractive index of the first material is 4.0049226185-4.0023352871, and the refractive index of the second material is 2.4172825199-2.3928100567.

[0051] The first material is germanium, and the second material is zinc selenide.

[0052] More preferably, the first lens, the third lens and the fifth lens are all made of the first material, and the second lens and the fourth lens are all made of the second material.

[0053] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention has two sides of the first lens for the propagation direction of the optical path, namely, the first lens incident surface and the first lens exit surface; the second lens has two sides for the second lens incident surface and the second lens exit surface; the third lens has two sides for the third lens incident surface and the third lens exit surface; the fourth lens has two sides for the fourth lens incident surface and the fourth lens exit surface; the fifth lens has two sides for the fifth lens incident surface and the fifth lens exit surface;

[0054] The numerical aperture of the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention is 0.5, and the object height is 1mm. It belongs to a small field of view and large aperture optical system, and the field curvature, astigmatism, distortion and magnification chromatic aberration are relatively small, and the spherical aberration and position chromatic aberration related to the aperture are mainly considered. The present application adopts the matching of positive and negative focal lengths of multiple lenses to correct spherical aberration; and selects appropriate lens materials, curvature radius and spacing to correct position chromatic aberration.

[0055] In order to further ensure the imaging quality, the radius of curvature of the incident surface of the first lens is -15.618±0.01mm, and the radius of curvature of the exit surface of the first lens is -13.511±0.01mm; the radius of curvature of the incident surface of the second lens is -19.722±0.01mm, and the radius of curvature of the exit surface of the second lens is -41.739±0.01mm; the radius of curvature of the incident surface of the third lens is -24.950±0.01mm, and the radius of curvature of the exit surface of the third lens is -21.286±0.01mm; the radius of curvature of the incident surface of the fourth lens is -44.781±0.01mm, and the radius of curvature of the exit surface of the fourth lens is -29.374±0.01mm; the radius of curvature of the incident surface of the fifth lens is 195.308±0.01mm, and the radius of curvature of the exit surface of the fifth lens is 284.891±0.01mm.

[0056] The meaning of the positive and negative values ​​of the radius of curvature is as follows: when the light propagates from left to right, if the center of curvature of the radius of curvature is to the right of the surface vertex, the radius of curvature is positive; if the center of curvature of the radius of curvature is to the left of the surface vertex, the radius of curvature is negative.

[0057] In order to better ensure the imaging quality, the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention has an object distance of 5.066±0.01mm; the center interval between the first lens and the second lens is 14.74±0.01mm; the center interval between the second lens and the third lens is 0.75±0.01mm; the center interval between the third lens and the fourth lens is 0.02±0.01mm; the center interval between the fourth lens and the fifth lens is 10.0±0.01mm; and the center interval between the fifth lens and the image plane is 196.927±1mm.

[0058] The center thickness of the first lens is 3.0±0.01mm; the center thickness of the second lens is 2.7±0.01mm; the center thickness of the third lens is 2.7±0.01mm; the center thickness of the fourth lens is 3.0±0.01mm; and the center thickness of the fifth lens is 4.0±0.01mm.

[0059] The long-wave infrared microscopic imaging lens used for the optical transmission function measuring instrument of the present invention has a wavelength range of 8 μm to 12 μm, a numerical aperture of 0.5, a magnification of 10 times, and an object height of 1 mm.

[0060] The present invention is described in detail below with reference to the accompanying drawings.

[0061] like Figure 1 As shown in the figure, the long-wave infrared microscopic imaging lens for optical transmission function measuring instrument of the present invention is provided with: first lens, second lens, third lens, fourth lens, fifth lens in sequence from left to right along the propagation direction of the optical path; the aperture stop is placed on the incident surface of the fifth lens. The object to be measured is placed at 5.066mm on the left side of the long-wave microscopic imaging lens, and the image plane imaging device is placed at 196.927mm on the right side of the last surface on the right side of the long-wave microscopic imaging lens.

[0062] Along the propagation direction of the light path, from left to right, the two surfaces of the first lens are the first lens incident surface S1 and the first lens exit surface S2, the two surfaces of the second lens are the second lens incident surface S3 and the second lens exit surface S4, the two surfaces of the third lens are the third lens incident surface S5 and the third lens exit surface S6, the two surfaces of the fourth lens are the fourth lens incident surface S7 and the fourth lens exit surface S8, and the two surfaces of the fifth lens are the fifth lens incident surface S9 and the fifth lens exit surface S10. Among them, the radius of curvature of the first lens incident surface S1 is -15.618mm, and the radius of curvature of the first lens exit surface S2 is -13.511mm; the radius of curvature of the second lens incident surface S3 is -19.722mm, and the radius of curvature of the second lens exit surface S4 is -41.739mm; the radius of curvature of the third lens incident surface S5 is -24.950mm, and the radius of curvature of the third lens exit surface S6 is -21.286mm; the radius of curvature of the fourth lens incident surface S7 is -44.781mm, and the radius of curvature of the fourth lens exit surface S8 is -29.374mm; the radius of curvature of the fifth lens incident surface S9 is 195.308mm, and the radius of curvature of the fifth lens exit surface S10 is 284.891mm.

[0063] The meanings of positive and negative values ​​of the radius of curvature are as follows: Figure 1 As shown, the light propagates from left to right. If the center of curvature of the radius of curvature is to the right of the surface vertex, the radius of curvature is positive. If the center of curvature of the radius of curvature is to the left of the surface vertex, the radius of curvature is negative.

[0064] The object distance of the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention is 5.066 mm; the center interval between the first lens and the second lens is 14.74 mm; the center interval between the second lens and the third lens is 0.75 mm; the center interval between the third lens and the fourth lens is 0.02 mm; the center interval between the fourth lens and the fifth lens is 10.0 mm; and the center interval between the fifth lens and the image plane is 196.927 mm.

[0065] The center thickness of the first lens is 3.0 mm; the center thickness of the second lens is 2.7 mm; the center thickness of the third lens is 2.7 mm; the center thickness of the fourth lens is 3.0 mm; and the center thickness of the fifth lens is 4.0 mm.

[0066] The first lens, the third lens and the fifth lens are all made of germanium, and the second lens and the fourth lens are all made of zinc selenide.

[0067] Table 1 Optical element parameter table of the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention

[0068]

[0069] The optical parameters of the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention are as follows:

[0070] Magnification: 10 times;

[0071] Numerical aperture: 0.5;

[0072] Wavelength: 8μm~12μm;

[0073] Object line field of view: 1mm;

[0074] Object distance: 5.066mm;

[0075] Rear working distance: 196.927mm;

[0076] Lens length: 40.91mm;

[0077] Object to image distance: 242.903mm.

[0078] The long-wave infrared microscopic imaging lens for the optical transmission signal measuring instrument of the present invention is a long-wave microscopic imaging lens with a wavelength range from 8 μm to 12 μm, receives a long-wave infrared wavelength spectrum signal, analyzes and calculates the long-wave information of the imaging, and is applied to the optical transmission signal measuring instrument to test the imaging performance of infrared lenses in various fields such as security monitoring, military, medical, industrial, firefighting and rescue, agriculture, scientific research, and transportation.

[0079] Depend on Figure 2It can be seen from the dispersion pattern that the dispersion spots in each field of view of the lens of the present invention are well corrected, and the dispersion spot radius is within the Airy disk. The RMS value of the dispersion spot radius on the axis is 9.45 μm, and the RMS value of the dispersion spot radius at the maximum field of view outside the axis is 19.87 μm.

[0080] Depend on Figure 3 It can be seen from the field curvature and distortion diagrams that the maximum field curvature of the lens of the present invention is 0.29 mm, and the maximum distortion is 0.0329%.

[0081] Depend on Figure 4 It can be seen from the optical transfer function curve shown that the optical transfer function of each field of view of the lens of the present invention is close to the diffraction limit.

[0082] In summary, the quality of the long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention can meet the use requirements of the optical transmission function measuring instrument.

[0083] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention is suitable for long-wave microscopic imaging and has excellent imaging performance; it has loose tolerance capacity and is easy to process and adjust; it has high testing efficiency and low processing cost and has high practical application value.

[0084] The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument of the present invention adopts matching of positive and negative optical powers of multiple lenses to correct spherical aberration based on aberration theory; selects appropriate lens materials, curvature radii and spacing to correct positional chromatic aberration; designs the imaging lens to have an imaging quality close to the diffraction limit; and can meet the use requirements of the optical transmission function measuring instrument.

[0085] By using the long-wave infrared microscopic imaging lens for an optical transfer function measuring instrument of the present invention, the self-developed optical transfer function measuring instrument can reach the accuracy of the imported f4000 type equipment, and can save a lot of costs for purchasing imported equipment for domestic purchasing units.

[0086] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument, characterized in that: The invention comprises: a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged along the propagation direction of the light path; an aperture stop is arranged on the incident surface of the fifth lens; The radius of curvature of the incident surface of the first lens is -15.618±0.01mm, and the radius of curvature of the exit surface of the first lens is -13.511±0.01mm; The radius of curvature of the incident surface of the second lens is -19.722±0.01mm, and the radius of curvature of the exit surface of the second lens is -41.739±0.01mm; The radius of curvature of the incident surface of the third lens is -24.950±0.01mm, and the radius of curvature of the exit surface of the third lens is -21.286±0.01mm; The curvature radius of the incident surface of the fourth lens is -44.781±0.01 mm, and the curvature radius of the exit surface of the fourth lens is -29.374±0.01 mm; The radius of curvature of the incident surface of the fifth lens is 195.308±0.01 mm, and the radius of curvature of the exit surface of the fifth lens is 284.891±0.01 mm.

2. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to claim 1, characterized in that: The refractive indexes of the materials of the first lens, the third lens and the fifth lens are 4.0049226185 to 4.0023352871 respectively; the refractive indexes of the materials of the second lens and the fourth lens are 2.4172825199 to 2.3928100567 respectively.

3. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to claim 2, characterized in that: The materials of the first lens, the third lens and the fifth lens are respectively germanium; the materials of the second lens and the fourth lens are respectively zinc selenide.

4. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to claim 1, characterized in that: The object distance is 5.066±0.01mm; the center distance between the first lens and the second lens is 14.74±0.01mm; the center distance between the second lens and the third lens is 0.75±0.01mm; the center distance between the third lens and the fourth lens is 0.02±0.01mm; the center distance between the fourth lens and the fifth lens is 10.0±0.01mm; the center distance between the fifth lens and the image plane is 196.927±1mm.

5. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to claim 1, characterized in that: The center thickness of the first lens is 3.0±0.01mm; the center thickness of the second lens is 2.7±0.01mm; the center thickness of the third lens is 2.7±0.01mm; the center thickness of the fourth lens is 3.0±0.01mm; and the center thickness of the fifth lens is 4.0±0.01mm.

6. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to any one of claims 1 to 5, characterized in that: The numerical aperture is 0.

5.

7. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to any one of claims 1 to 5, characterized in that: The wavelength range is 8μm to 12μm.

8. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to any one of claims 1 to 5, characterized in that: The magnification is 10x.

9. The long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument according to any one of claims 1 to 5, characterized in that: The object height is 1mm.

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