Medium-wave infrared microscope lens for high-speed temperature measurement

Abstract

The invention discloses a medium-wave infrared microscope lens for high-speed temperature measurement, and belongs to the field of infrared temperature measurement. The lens group is mainly made of germanium, monocrystalline silicon and chalcogenide glass. Comprising six spherical lenses and two aspherical lenses, wherein the sixth lens and the eighth lens are double-sided aspherical lenses; the first lens, the second lens, the third lens and the fifth lens are made of monocrystalline silicon. The fourth lens, the sixth lens and the eighth lens are made of germanium; the seventh lens is made of IRG24 chalcogenide glass; the lens group is formed by coaxially installing and arranging first to eighth lenses in sequence. The device has the advantages of high magnification and large numerical aperture, can realize extremely high light inlet efficiency and imaging quality, and ensures the precision of temperature field measurement in a micron-sized high-speed scene. The device has the advantage of long working distance, so that the device is more suitable for measurement scenes needing protective measures and other front optical instruments.

Description

Technical Field

[0001] The present invention belongs to the field of infrared optical technology, and in particular relates to an infrared microscope lens for measuring temperature fields in high-speed dynamic scenes. Background Art

[0002] High-speed infrared temperature measurement technology has a wide range of applications in scientific research. For example, the hotspot initiation mechanism of energetic materials under non-impact loading is a key research topic, which holds significant scientific and engineering value for ensuring the safety of energetic material production and applications. Under non-impact loading, energetic materials generate dissipative mechanisms such as friction and plastic deformation, causing localized, dramatic temperature rises and forming "hotspots." Therefore, temperature field measurement experiments under non-impact loading are essential to further understand the ignition mechanism of energetic materials under non-impact loading.

[0003] The hotspot initiation process requires microsecond-level time measurement accuracy and micron-level spatial resolution. This requires the infrared microscope lens to have both a high magnification and a large numerical aperture to improve light entry efficiency and ensure measurement accuracy and a minimum temperature limit. For energetic materials, which have energy-releasing properties, the infrared microscope lens must have a sufficient working distance to allow for the installation of protective measures to ensure equipment safety. Summary of the Invention

[0004] The purpose of the present invention is to provide a medium-wave infrared microscope lens for high-speed temperature measurement, which can achieve extremely high light input efficiency and imaging quality. It uses high infrared transmittance materials such as germanium, single crystal silicon, and sulfide glass, has good transmittance and thermal stability, and ensures the accuracy of temperature field measurement in micron-level high-speed temperature measurement scenarios; the present invention has the advantages of high magnification, large numerical aperture, and long working distance, making the present invention more suitable for measurement scenarios that require loading protective measures and other front-end optical instruments.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention discloses a medium-wave infrared microscope lens for high-speed temperature measurement, which is a lens group mainly made of germanium, single-crystal silicon and chalcogenide glass; it includes 6 spherical lenses and 2 aspherical lenses, among which the 6th lens and the 8th lens are double-sided aspherical lenses; the 1st lens, the 2nd lens, the 3rd lens and the 5th lens are made of single-crystal silicon; the 4th lens, the 6th lens and the 8th lens are made of germanium; the 7th lens is made of IRG24 chalcogenide glass; the lens group is coaxially mounted and arranged in sequence from the 1st lens to the 8th lens.

[0007] Furthermore, the medium-wave infrared microscope lens has a numerical aperture of 0.72, a magnification of 6 times, and a working distance of 50 mm, where the working distance is the distance between the end face of the lens and the observed object.

[0008] Furthermore, the sixth and eighth lenses are aspherical lenses, with a total of four aspherical surfaces, which are used to eliminate spherical aberration and coma and improve image quality. The rest are spherical lenses to simplify the processing technology; the aspherical surfaces meet the aspherical formula:

[0009]

[0010] Among them, Z is the distance vector height from the aspheric surface vertex when the aspheric surface is at a height r along the optical axis; c = 1 / r; r is the paraxial curvature fitting radius of the mirror surface; k is the cone coefficient; A, B, C, and D are high-order aspheric coefficients.

[0011] Furthermore, the single crystal silicon material of the first, second, third and fifth lenses has high infrared transmittance and good thermal stability; the germanium of the fourth, sixth and eighth lenses has high refractive index and low dispersion characteristics, suitable for infrared band imaging; the IRG24 chalcogenide glass of the seventh lens has excellent infrared transmittance and thermal stability.

[0012] Furthermore, the center thickness of the first lens is 16.23mm, the object side curvature radius is -122.95mm, and the image side curvature radius is -92.19mm; the center thickness of the second lens is 11.11mm, the object side curvature radius is -3108.48mm, and the image side curvature radius is -418.5mm; the center thickness of the third lens is 20.52mm, the object side curvature radius is -85.08mm, and the image side curvature radius is 126.49mm; the center thickness of the fourth lens is 5.2mm, the object side curvature radius is 125.73mm, and the image side curvature radius is The radius is 66.25mm; the center thickness of the 5th lens is 16.98mm, the object side curvature radius is 107.39mm, and the image side curvature radius is 120.86mm; the center thickness of the 6th lens is 17mm, the object side curvature radius is 100.75mm, and the image side curvature radius is 49.32mm; the center thickness of the 7th lens is 17mm, the object side curvature radius is 36.73mm, and the image side curvature radius is 67.31mm; the center thickness of the 8th lens is 15mm, the object side curvature radius is 24.22mm, and the image side curvature radius is 10.96mm.

[0013] Furthermore, the lens operates in a wavelength range of 3 μm to 5 μm.

[0014] This embodiment discloses a method for operating a medium-wave infrared microscope lens for high-speed temperature measurement. The medium-wave infrared lens is threadedly mounted in front of a high-speed infrared array. The high-speed infrared array has an extremely high frame rate and short exposure time. The medium-wave infrared microscope lens can meet the infrared radiation intensity requirements of the high-speed infrared array within this extremely short exposure time, achieving the required signal-to-noise ratio for measurement. The medium-wave infrared microscope lens has a 50mm working distance, maintaining a sufficient safe distance from the energetic material sample being tested, while also allowing for the installation of protective equipment and other optical components.

[0015] Beneficial effects:

[0016] 1. The present invention discloses a medium-wave infrared microscope lens for high-speed temperature measurement, which adopts a large numerical aperture and aspheric lens design. While improving the spatial resolution of the infrared camera by 6 times, it achieves extremely high light input efficiency and imaging quality. It uses high infrared transmittance materials such as germanium, single crystal silicon, and sulfide glass, and has good transmittance and thermal stability, ensuring the accuracy of temperature field measurement in micron-level high-speed temperature measurement scenarios.

[0017] 2. The present invention discloses a medium-wave infrared microscope lens for high-speed temperature measurement, which uses two smaller aspheric lenses to eliminate spherical aberration and coma, improve imaging quality, and optimize the processing technology of aspheric lenses.

[0018] 3. The present invention discloses a medium-wave infrared microscope lens for high-speed temperature measurement, which adopts a large-diameter objective lens design and has a large working distance. It is suitable for measurement scenarios that require loading protective measures and other front-end optical instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the optical structure;

[0020] Figure 2 is a spot diagram;

[0021] Figure 3 is the MTF curve;

[0022] Among them: S1—object side of the 1st lens, S2—image side of the 1st lens, S3—object side of the 2nd lens, S4—object side of the 2nd lens, S5—object side of the 3rd lens, S6—image side of the 3rd lens, S7—object side of the 4th lens, S8—object side of the 4th lens, S9—object side of the 5th lens, S10—object side of the 5th lens, S11—object side of the 6th lens, S12—object side of the 6th lens, S13—object side of the 7th lens, S14—object side of the 7th lens, S15—object side of the 8th lens, S16—object side of the 8th lens. DETAILED DESCRIPTION

[0023] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0024] Example 1:

[0025] For ease of understanding, the following explains the relevant terms: Object side: The side of the lens where the subject is located is called the object side; object side: The surface of the lens closest to the object side is called the object side; image side: The side of the lens where the image of the subject is located is called the image side; image side: The surface of the lens closest to the image side is called the image side.

[0026] like Figure 1 As shown, this embodiment is a medium-wave infrared microscope lens for high-speed temperature measurement, the lens is a lens group made of germanium, single crystal silicon and chalcogenide glass; it includes 6 spherical lenses and 2 aspherical lenses, among which the object side surface S11 and image side surface S12 of the 6th lens and the object side surface S15 and image side surface S16 of the 8th lens are aspherical; the 1st lens, the 2nd lens, the 3rd lens and the 5th lens are made of single crystal silicon; the 4th lens, the 6th lens and the 8th lens are made of germanium; the 7th lens is made of IRG24 chalcogenide glass; it has a numerical aperture of 0.72, a magnification of 6 times, and a working distance of 50 mm (the distance between the observed object and the lens end face).

[0027] Table 1 Parameters of each component

[0028]

[0029]

[0030] As a specific implementation method, the sixth and eighth lenses are aspherical lens designs, with a total of four aspherical surfaces, used to eliminate spherical aberration and coma and improve image quality. The rest are spherical lenses to simplify the processing technology. The aspherical surface satisfies the aspherical surface formula:

[0031]

[0032] Among them, Z is the distance vector height from the aspheric surface vertex when the aspheric surface is at a height r along the optical axis; c = 1 / r; r is the paraxial curvature fitting radius of the mirror surface; k is the cone coefficient; A, B, C, and D are high-order aspheric coefficients.

[0033] Table 2 Lens aspheric parameters

[0034] Surface number S11 S12 S15 S16 A 2.8984e-07 8.4390e-09 -7.3597e-06 -0.0001 B 1.7652e-09 1.3807e-11 -1.5970e-08 -1.9173 C 0 3.0518e-06 -4.3304e-10 8.888e-08 D 0 0 -3.3583e-12 -1.5348e-08

[0035] Figure 2 、 Figure 3The following are the lens's spot diagram and MTF plot. In the MTF plot, the horizontal axis represents different spatial frequencies, and the vertical axis represents modulation. All fields of view represent the MTF curves in the meridional plane. It can be seen that the MTF is close to the diffraction limit, and the RMS diameter of the diffuse spot is smaller than the Airy disk diameter, indicating excellent image quality.

[0036] This embodiment discloses a method for operating a medium-wave infrared microscope lens for high-speed temperature measurement. The medium-wave infrared lens is threadedly mounted in front of a high-speed infrared array. The high-speed infrared array has an extremely high frame rate and short exposure time. The medium-wave infrared microscope lens can meet the infrared radiation intensity requirements of the high-speed infrared array within this short exposure time, achieving the required signal-to-noise ratio for measurement. The medium-wave infrared microscope lens has a 50mm working distance, maintaining a sufficient safe distance from the energetic material sample being tested while allowing for the installation of protective equipment and other optical components.

[0037] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A medium-wave infrared microscope lens for high-speed temperature measurement, characterized in that: It is a lens group mainly made of germanium, single crystal silicon and chalcogenide glass; it includes 6 spherical lenses and 2 aspherical lenses, among which the 6th and 8th lenses are double-sided aspherical lenses; the 1st lens, the 2nd lens, the 3rd lens and the 5th lens are made of single crystal silicon; the 4th lens, the 6th lens and the 8th lens are made of germanium; the 7th lens is made of IRG24 chalcogenide glass; the lens group is coaxially mounted in sequence from the 1st lens to the 8th lens.

2. The medium-wave infrared microscope lens for high-speed temperature measurement according to claim 1, characterized in that: The MWIR microscope lens also has a numerical aperture of 0.72, a magnification of 6 times, and a working distance of 50mm, where the working distance is the distance from the mechanical end face of the lens to the object being observed.

3. The medium-wave infrared microscope lens for high-speed temperature measurement according to claim 2, characterized in that: The 6th and 8th lenses are aspherical lenses, with a total of 4 aspherical surfaces, which are used to eliminate spherical aberration and coma and improve image quality. The rest are spherical lenses to simplify the processing technology; the aspherical surfaces meet the aspherical formula: Among them, Z is the distance vector height from the aspheric surface vertex when the aspheric surface is at a height r along the optical axis; c = 1 / r; r is the paraxial curvature fitting radius of the mirror surface; k is the cone coefficient; A, B, C, and D are high-order aspheric coefficients.

4. The medium-wave infrared microscope lens for high-speed temperature measurement according to claim 3, characterized in that: The single crystal silicon material of the 1st, 2nd, 3rd and 5th lenses has high infrared transmittance and good thermal stability; the germanium of the 4th, 6th and 8th lenses has high refractive index and low dispersion characteristics, suitable for infrared imaging; the IRG24 chalcogenide glass of the 7th lens has excellent infrared transmittance and thermal stability.

5. A medium-wave infrared microscope lens for high-speed temperature measurement according to claim 1, 2, 3 or 4, characterized in that: The center thickness of the first lens is 16.23mm, the object side curvature radius is -122.95mm, and the image side curvature radius is -92.19mm; the center thickness of the second lens is 11.11mm, the object side curvature radius is -3108.48mm, and the image side curvature radius is -418.5mm; the center thickness of the third lens is 20.52mm, the object side curvature radius is -85.08mm, and the image side curvature radius is 126.49mm; the center thickness of the fourth lens is 5.2mm, the object side curvature radius is 125.73mm, and the image side curvature radius is The center thickness of the 5th lens is 16.98mm, the object side curvature radius is 107.39mm, and the image side curvature radius is 120.86mm; the center thickness of the 6th lens is 17mm, the object side curvature radius is 100.75mm, and the image side curvature radius is 49.32mm; the center thickness of the 7th lens is 17mm, the object side curvature radius is 36.73mm, and the image side curvature radius is 67.31mm; the center thickness of the 8th lens is 15mm, the object side curvature radius is 24.22mm, and the image side curvature radius is 10.96mm.

6. The medium-wave infrared microscope lens for high-speed temperature measurement according to claim 5, characterized in that: The lens operates in a wavelength range of 3 μm to 5 μm.

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