A long-wave infrared microscope imaging lens for optical transmission function measuring instrument

Abstract

The present invention relates to a long-wave infrared microscopic imaging lens for an optical transducer, and relates to the field of optical testing technology. The long-wave infrared microscopic imaging lens comprises a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in sequence along the optical path. An aperture stop is provided on the incident surface of the fifth lens. The long-wave infrared microscopic imaging lens for an optical transducer of the present invention is suitable for long-wave microscopic imaging, exhibits excellent imaging performance, has a wide tolerance, is easy to process and adjust, has high testing efficiency, and has low processing costs, thus possessing high practical application value.

Description

Technical Field

[0001] The present 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] Application areas of infrared optical lenses include:

[0003] 1. Security monitoring field

[0004] At night or in low-light conditions, long-wave infrared lenses produce clear images, effectively monitoring the surveillance area and promptly detecting potential security threats such as theft and illegal intrusion, making them a vital component of security monitoring systems. Long-wave infrared thermal imagers offer high concealment, a low false alarm rate, and 24 / 7 operation, making them crucial for ensuring the security of critical facilities, public spaces, border crossings, 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 measure human body temperature quickly and accurately, 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 the equipment, promptly discover abnormal conditions such as overheating and overcooling of the equipment, and predict potential failures of the equipment so that maintenance and repairs can be carried out in advance, reducing the risk of equipment damage and production shutdowns.

[0011] 5. Firefighting and rescue field

[0012] Long-wave infrared lenses have strong penetrating power. At the fire scene, they can penetrate smoke, helping 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 temperature differences, it can determine the growth status, moisture content, and the presence of pests and diseases, providing a basis for decision-making in agricultural production. It can also be used to monitor environmental parameters such as soil moisture, helping farmers to optimize irrigation 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 property characterization, and biomolecule detection. For example, it can analyze and characterize the key chemical information of various compounds to achieve accurate identification and analysis of chemical substances.

[0017] 8. Transportation

[0018] For the vehicle's autonomous driving system, long-wave infrared lenses 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 long-wave infrared lenses in these application areas, measuring their imaging quality and parameters such as focal length is crucial. Optical transfer function meters are key equipment for evaluating the imaging quality of these lenses. These instruments measure the transfer functions of long-wave infrared lenses at different spatial frequencies, objectively assessing their image quality. They are suitable for the assembly, adjustment, and inspection of long-wave infrared lenses and possess universal applicability.

[0020] An optical transfer function (OTF) instrument consists of a target generator, collimator, and image analyzer. The long-wavelength microscopic imaging lens is a crucial component of the image analyzer, and its designed imaging results are crucial for the overall performance of the instrument. However, existing long-wavelength infrared optical lens TTF testing equipment must be imported from abroad, and the associated equipment costs are high. 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 coefficient test equipment needs to be imported from abroad and the supporting equipment requires high funding, and provides a long-wave infrared microscopic imaging lens for an optical transmission coefficient 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 provided 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 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;

[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 indices of the materials of the first lens, the third lens, and the fifth lens are 4.0049226185 to 4.0023352871 respectively; the refractive indices 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; and 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 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; and the center distance 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, has excellent imaging performance, has a wide tolerance capacity, is easy to process and adjust, has high testing efficiency, 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 corrects spherical aberration by matching the positive and negative optical powers of multiple lenses based on aberration theory; corrects positional chromatic aberration by selecting appropriate lens materials, curvature radii, and spacing; and designs the imaging lens to have imaging quality close to the diffraction limit, thereby meeting the use requirements of an 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 domestically developed optical transfer function measuring instrument can achieve the accuracy of the imported f4000 type equipment, which can save a lot of costs for purchasing foreign imported equipment for domestic purchasing units. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Figure 1 The figure is a schematic diagram of the optical design of the long-wave infrared microscopic imaging lens for the optical transmission function measuring instrument of the present invention.

[0043] Figure 2 Schematic diagram of the diffuse spot of the long-wave infrared microscopic imaging lens used in the optical transmission function measuring instrument of the present invention.

[0044] Figure 3 Schematic diagram of 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 The figure is a schematic diagram of an optical transfer function curve of a long-wave infrared microscopic imaging lens for an optical transfer function measuring instrument according to the present invention. DETAILED DESCRIPTION

[0046] The long-wave infrared microscopic imaging lens for an optical transmission signal measuring instrument of the present invention comprises: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, arranged in sequence along 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 forms the rear tube lens. Parallel light is generated between the objective lens and the tube lens, allowing alignment of the tube lens with the imaging device at the rear image plane during use, after which the front objective lens can be 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 the 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 under test is located 5.066 mm in front of the long-wave infrared microscope imaging lens. The long-wave infrared imaging device is located on the image plane. The long-wave infrared microscope imaging lens has a numerical aperture of 0.5 and a magnification of 10.

[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 8μm to 12μm. The long-wave infrared imaging device receives long-wave spectrum signals and analyzes and calculates the optical signals to obtain the optical transfer function of the lens under test.

[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 signal measuring instrument of the present invention has two surfaces of the first lens serving as a first lens incident surface and a first lens exit surface along the optical path propagation direction; two surfaces of the second lens serving as a second lens incident surface and a second lens exit surface; two surfaces of the third lens serving as a third lens incident surface and a third lens exit surface; two surfaces of the fourth lens serving as a fourth lens incident surface and a fourth lens exit surface; and two surfaces of the fifth lens serving as a fifth lens incident surface and a fifth lens exit surface.

[0054] The long-wave infrared microscopic imaging lens for optical transducers of this invention has a numerical aperture of 0.5 and an object height of 1 mm. This system is characterized by a small field of view and a large aperture, resulting in minimal field curvature, astigmatism, distortion, and chromatic aberration of magnification. The primary considerations are spherical aberration and positional chromatic aberration related to the aperture. This application uses multiple lenses with matching positive and negative optical powers to correct for spherical aberration; and selects appropriate lens materials, curvature radii, and spacing to correct for positional chromatic aberration.

[0055] 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] To better ensure imaging quality, the long-wave infrared microscopic imaging lens for the optical transmission signal measuring instrument of the present invention has an object distance of 5.066±0.01mm; the center spacing between the first lens and the second lens is 14.74±0.01mm; the center spacing between the second lens and the third lens is 0.75±0.01mm; the center spacing between the third lens and the fourth lens is 0.02±0.01mm; the center spacing between the fourth lens and the fifth lens is 10.0±0.01mm; and the center spacing 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 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 will be described in detail below with reference to the accompanying drawings.

[0061] like Figure 1 As shown, the long-wave infrared microscope imaging lens for an optical transmission function measuring instrument of the present invention comprises, from left to right, the following lens elements, arranged in order along the optical path: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens; an aperture stop is placed on the incident surface of the fifth lens. The object to be measured is placed 5.066 mm to the left of the long-wave infrared microscope imaging lens, and the image plane imaging device is placed 196.927 mm to the right of the last surface on the right side of the long-wave infrared microscope imaging lens.

[0062] Along the direction of light propagation, 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 curvature radius are as follows: Figure 1 As shown, the light propagates from left to right. If the center of curvature of the curvature radius is to the right of the surface vertex, the curvature radius is positive. If the center of curvature of the curvature radius is to the left of the surface vertex, the curvature radius is negative.

[0064] The object distance of the long-wave infrared microscopic imaging lens for the optical transmission signal measuring instrument of the present invention is 5.066 mm; the center distance between the first lens and the second lens is 14.74 mm; the center distance between the second lens and the third lens is 0.75 mm; the center distance between the third lens and the fourth lens is 0.02 mm; the center distance between the fourth lens and the fifth lens is 10.0 mm; and the center distance 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 parameters 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 an optical transmission signal measuring instrument of the present invention has a wavelength range from 8 μm to 12 μm. It receives a long-wave infrared 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, fire rescue, agriculture, scientific research, and transportation.

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

[0080] Depend on Figure 3 As shown in the field curvature and distortion diagrams, 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 curves shown that the optical transfer functions of the lens of the present invention in each field of view are close to the diffraction limit.

[0082] In summary, the quality of the long-wave infrared microscope imaging lens for the 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, has excellent imaging performance, has a wide tolerance capacity, is easy to process and adjust, has high testing efficiency, 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 corrects spherical aberration by matching the positive and negative optical powers of multiple lenses based on aberration theory; corrects positional chromatic aberration by selecting appropriate lens materials, curvature radii, and spacing; and designs the imaging lens to have imaging quality close to the diffraction limit, thereby meeting the use requirements of an 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 domestically developed optical transfer function measuring instrument can achieve the accuracy of the imported f4000 type equipment, which can save a lot of costs for purchasing foreign imported equipment for domestic purchasing units.

[0086] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A long-wave infrared microscopic imaging lens for an optical transmission function measuring instrument, characterized in that: The optical system comprises: a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence along the optical path; an aperture stop is provided 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 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±0.01 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 indices of the materials of the first lens, the third lens, and the fifth lens are 4.0049226185 to 4.0023352871 respectively; the refractive indices 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 first lens, the third lens, and the fifth lens are made of germanium respectively; the second lens and the fourth lens are made of zinc selenide respectively.

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; and 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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