Deep ultraviolet microscope objective lens and microscope

Abstract

The invention provides a deep ultraviolet microscope objective lens and a microscope. The objective lens of the deep ultraviolet microscope comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged on the same optical axis from an object side to an image side. According to the scheme of the invention, the method is designed according to the wavelength range of 260-262 nm, and the design value of the resolution in the wavelength range is consistent with the theoretical value; independent design is completely achieved, and the problem that an existing 50-time objective lens cannot meet many use requirements in optical detection is solved; specific parameters and structures of all the lenses are set, so that the amplification factor of the objective lens of the deep ultraviolet microscope is 50 times, the object space view field is 0.6 mm, a tube lens with the focal length of 200 mm can be used in a matched mode, the working distance is 13 mm, the numerical aperture is 0.528, the object space view field and the working distance of the objective lens of the deep ultraviolet microscope are improved, and then the overall performance of the microscope is improved.

Description

Technical Field

[0001] The invention relates to the field of microscopes, in particular to a deep ultraviolet microscope objective lens and a microscope. Background Art

[0002] With the improvement of semiconductor manufacturing process, the transistor density of semiconductor chips is getting higher and higher, and the requirements for the resolution of the detection system are also getting higher and higher. According to the Rayleigh criterion of optical resolution limit: R = 0.61λ / NA, it can be known that to improve the resolution of the optical system, it is necessary to shorten the wavelength or increase the numerical aperture. In the field of semiconductor detection, the increase of numerical aperture has its limitations, and there is almost no available space for immersion objective lenses, so shortening the wavelength has become the best choice. At present, the deep ultraviolet band is more and more widely used in optical detection systems, but there are few mature deep ultraviolet objective lenses on the domestic market, and the few optional objective lenses cannot meet all usage needs. Summary of the invention

[0003] An object of the present invention is to provide a deep ultraviolet microscope objective lens that improves the resolution within a specific ultraviolet wavelength range.

[0004] A further object of the present invention is to increase the object field of view and working distance of the deep ultraviolet microscope objective lens, thereby improving the overall performance of the microscope.

[0005] In particular, the present invention provides a deep ultraviolet microscope objective lens, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are arranged in sequence from the object side to the image side on the same optical axis; the first lens has a concave surface facing the object side and a convex surface facing the image side; the second lens has a concave surface facing the object side and a convex surface facing the image side; the third lens has a concave surface facing the object side and a convex surface facing the image side; the fourth lens has a convex surface facing the object side and a convex surface facing the image side; the fifth lens has a convex surface facing the object side and a concave surface facing the image side; the sixth lens has a concave surface facing the object side and a convex surface facing the image side; the seventh lens has a concave surface facing the object side and a convex surface facing the image side; the eighth lens has a convex surface facing the object side and a concave surface facing the image side.

[0006] Optionally, the first lens, the second lens, the third lens, the fifth lens, and the seventh lens are all positive meniscus lenses; the fourth lens is a double convex positive lens; and the sixth lens and the eighth lens are all negative meniscus lenses.

[0007] Optionally, the first lens, the third lens, the fifth lens, and the seventh lens are all made of calcium fluoride; and the second lens, the fourth lens, the sixth lens, and the eighth lens are all made of fused quartz.

[0008] Optionally, the surface of the first lens facing the object side is the first mirror surface, and the surface of the first lens facing the image side is the second mirror surface; the surface of the second lens facing the object side is the third mirror surface, and the surface of the second lens facing the image side is the fourth mirror surface; the surface of the third lens facing the object side is the fifth mirror surface, and the surface of the third lens facing the image side is the sixth mirror surface; the surface of the fourth lens facing the object side is the seventh mirror surface, and the surface of the fourth lens facing the image side is the eighth mirror surface; the surface of the fifth lens facing the object side is the ninth mirror surface, and the surface of the fifth lens facing the image side is the tenth mirror surface; the surface of the sixth lens facing the object side is the eleventh mirror surface, and the surface of the sixth lens facing the image side is the eleventh mirror surface. The surface facing the image side is the twelfth mirror surface; the surface of the seventh lens facing the object side is the thirteenth mirror surface, and the surface of the seventh lens facing the image side is the fourteenth mirror surface; the surface of the eighth lens facing the object side is the fifteenth mirror surface, and the surface of the eighth lens facing the image side is the sixteenth mirror surface. The curvature radii of the first mirror surface, the second mirror surface, the third mirror surface, the fourth mirror surface, the fifth mirror surface, the sixth mirror surface, the eighth mirror surface, the tenth mirror surface, the eleventh mirror surface, the twelfth mirror surface, the thirteenth mirror surface and the fourteenth mirror surface are all negative numbers; the curvature radii of the seventh mirror surface, the ninth mirror surface, the fifteenth mirror surface and the sixteenth mirror surface are all positive numbers.

[0009] Optionally, the radius of curvature of the first mirror surface is -14.6 to -14.58 mm; the radius of curvature of the second mirror surface is -9.96 to -9.94 mm; the radius of curvature of the third mirror surface is -28.89 to -28.87 mm; the radius of curvature of the fourth mirror surface is -15.49 to -15.47 mm; the radius of curvature of the fifth mirror surface is -117.24 to -117.22 mm; the radius of curvature of the sixth mirror surface is -24.99 to -24.97 mm; the radius of curvature of the seventh mirror surface is 79.12 to 79.14 mm; the radius of curvature of the eighth mirror surface is -53.23 to -53.21 mm ; The radius of curvature of the ninth mirror surface is 26.71 to 26.73mm; the radius of curvature of the tenth mirror surface is -676.94 to -676.92mm; the radius of curvature of the eleventh mirror surface is -10.72 to -10.7mm; the radius of curvature of the twelfth mirror surface is -200.48 to -200.46mm; the radius of curvature of the thirteenth mirror surface is -9.93 to -9.91mm; the radius of curvature of the fourteenth mirror surface is -12.7 to -12.68mm; the radius of curvature of the fifteenth mirror surface is 84.1 to 84.12mm; the radius of curvature of the sixteenth mirror surface is 13.94 to 13.96mm.

[0010] Optionally, the clear aperture of the first mirror is 5.94 mm; the clear aperture of the second mirror is 6.39 mm; the clear aperture of the third mirror is 6.94 mm; the clear aperture of the fourth mirror is 7.41 mm; the clear aperture of the fifth mirror is 7.8 mm; the clear aperture of the sixth mirror is 8.05 mm; the clear aperture of the seventh mirror is 8.24 mm; the clear aperture of the eighth mirror is 8.26 mm; The clear aperture of the ninth mirror is 8.04mm; the clear aperture of the tenth mirror is 6.78mm; the clear aperture of the eleventh mirror is 3.25mm; the clear aperture of the twelfth mirror is 3.22mm; the clear aperture of the thirteenth mirror is 3.2mm; the clear aperture of the fourteenth mirror is 4.27mm; the clear aperture of the fifteenth mirror is 3.62mm; and the clear aperture of the sixteenth mirror is 3.45mm.

[0011] Optionally, the mirror distance between the first mirror plane and the second mirror plane is 1.99 to 2.01 mm; the mirror distance between the second mirror plane and the third mirror plane is 0.09 to 0.11 mm; the mirror distance between the third mirror plane and the fourth mirror plane is 2.49 to 2.51 mm; the mirror distance between the fourth mirror plane and the fifth mirror plane is 0.09 to 0.11 mm; the mirror distance between the fifth mirror plane and the sixth mirror plane is 2.49 to 2.51 mm; the mirror distance between the sixth mirror plane and the seventh mirror plane is 0.09 to 0.11 mm; the mirror distance between the seventh mirror plane and the eighth mirror plane is 1.98 to 2 mm; the mirror distance between the eighth mirror plane and the ninth mirror plane is 4.71 to 4.71 mm. .73mm; the mirror distance between the ninth mirror plane and the tenth mirror plane is 11.68 to 11.7mm; the mirror distance between the tenth mirror plane and the eleventh mirror plane is 19.65 to 19.67mm; the mirror distance between the eleventh mirror plane and the twelfth mirror plane is 1.99 to 2.01mm; the mirror distance between the twelfth mirror plane and the thirteenth mirror plane is 1.19 to 1.21mm; the mirror distance between the thirteenth mirror plane and the fourteenth mirror plane is 11.99 to 12.01mm; the mirror distance between the fourteenth mirror plane and the fifteenth mirror plane is 19.99 to 20.01mm; the mirror distance between the fifteenth mirror plane and the sixteenth mirror plane is 4.43 to 4.45mm.

[0012] Optionally, the deep ultraviolet microscope objective lens is applicable to a wavelength range of 260 to 262 nm, and the focal length of the tube lens that can be used in combination is 200 mm.

[0013] Optionally, an edge or an outer frame of the first mirror serves as an aperture stop.

[0014] According to another aspect of the present invention, there is also provided a microscope comprising any one of the above-mentioned deep ultraviolet microscope objective lenses.

[0015] The deep ultraviolet microscope objective lens of the present invention is designed for the wavelength range of 260 to 262 nm, and the design value of the resolution within this wavelength range is consistent with the theoretical value; and it is completely independently designed, solving the problem that the existing 50x objective lens cannot meet many usage requirements in optical detection.

[0016] Furthermore, the deep ultraviolet microscope objective lens of the present invention, by setting the specific parameters and structures of each lens, makes the magnification of the deep ultraviolet microscope objective lens be 50 times, and the object field of view be 0.6 mm, which has a field of view higher than that of a conventional commercial 50-times microscope objective lens, and can be used with a tube lens with a focal length of 200 mm. The working distance is 13 mm, which is larger than that of a conventional objective lens, and the corresponding numerical aperture is larger, which is 0.528, and can improve the object field of view and working distance of the deep ultraviolet microscope objective lens, thereby improving the overall performance of the microscope.

[0017] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0019] Figure 1 is a schematic structural diagram of a deep ultraviolet microscope objective lens according to an embodiment of the present invention;

[0020] Figure 2 is a spot diagram of different fields of view of a deep ultraviolet microscope objective according to an embodiment of the present invention;

[0021] Figure 3 is a modulation transfer function curve diagram of a deep ultraviolet microscope objective according to an embodiment of the present invention; and

[0022] Figure 4 is a field curvature distortion diagram of a deep ultraviolet microscope objective according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] This embodiment provides a deep ultraviolet microscope objective lens that can improve the resolution within a specific ultraviolet wavelength range. Figure 1 FIG. 1 is a schematic diagram of the structure of a deep ultraviolet microscope objective lens according to an embodiment of the present invention. Figure 1As shown, the deep ultraviolet microscope objective lens of this embodiment includes: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8, which are arranged in sequence from the object side to the image side with the same optical axis.

[0024] Among them, the first lens L1 has a concave surface facing the object side and a convex surface facing the image side; the second lens L2 has a concave surface facing the object side and a convex surface facing the image side; the third lens L3 has a concave surface facing the object side and a convex surface facing the image side; the fourth lens L4 has a convex surface facing the object side and a convex surface facing the image side; the fifth lens L5 has a convex surface facing the object side and a concave surface facing the image side; the sixth lens L6 has a concave surface facing the object side and a convex surface facing the image side; the seventh lens L7 has a concave surface facing the object side and a convex surface facing the image side; the eighth lens L8 has a convex surface facing the object side and a concave surface facing the image side.

[0025] In a specific embodiment, the first lens L1, the second lens L2, the third lens L3, the fifth lens L5, and the seventh lens L7 are all positive meniscus lenses. Among them, the positive meniscus lens refers to a lens composed of two curved surfaces with similar curvature radii, which has a positive focal length. The positive meniscus lens can usually be used to reduce the focal length of another lens and increase the numerical aperture. When expanding, shrinking or diverging collimated light, the light beam can be incident on the convex surface of the positive meniscus lens, thereby reducing spherical aberration. When used for converging light, the light beam can be incident on the concave surface of the positive meniscus lens.

[0026] The fourth lens L4 is a double convex positive lens. The sixth lens L6 and the eighth lens L8 are both negative meniscus lenses. A negative meniscus lens refers to a lens composed of two curved surfaces with similar curvature radii and has a negative focal length. Negative meniscus lenses can generally be used for applications such as beam expansion, increasing focal length, and reducing numerical aperture. When expanding beams or diverging collimated light, the light beam can be incident on the convex surface of the negative meniscus lens, thereby reducing spherical aberration. When used for converging light collimation, the light beam can be incident on the concave surface.

[0027] In a preferred embodiment, the specific materials of the first lens L1 to the eighth lens L8 can refer to Table 1. As shown in Table 1, the first lens L1, the third lens L3, the fifth lens L5, and the seventh lens L7 can all be made of calcium fluoride. Calcium fluoride has high refractive index and low dispersion characteristics. Lenses made of calcium fluoride are particularly suitable for the ultraviolet spectrum region and can provide clear imaging effects.

[0028] The second lens L2, the fourth lens L4, the sixth lens L6, and the eighth lens L8 can all be made of fused quartz. Lenses made of fused quartz have extremely high light transmittance and can transmit ultraviolet and infrared rays; their thermal expansion coefficient is extremely small and has good thermal shock resistance; they are heat-resistant and acid-resistant, and have good chemical stability; they have ultra-low roughness and excellent surface shape deviation, and are suitable for high-precision optical applications; they have few surface defects and a large aperture, and are suitable for a variety of optical applications; aspherical lenses can correct spherical aberrations, reduce the total number of components in the optical system, and make the structural design more compact and fully functional.

[0029] In summary, all lenses used in the deep ultraviolet microscope objective of this embodiment are made of calcium fluoride or fused quartz, and all lens surfaces are spherical, which is very easy to process, can effectively reduce the processing difficulty, and improve the processing efficiency and processing quality.

[0030] Table 1

[0031] Lens Name Material First lens L1 Calcium Fluoride Second lens L2 Fused Silica The third lens L3 Calcium Fluoride The fourth lens L4 Fused Silica Fifth lens L5 Calcium Fluoride Sixth lens L6 Fused Silica Seventh lens L7 Calcium Fluoride The eighth lens L8 Fused Silica

[0032] In a specific embodiment, the surface of the first lens L1 facing the object side is the first mirror surface S1, and the surface of the first lens L1 facing the image side is the second mirror surface S2; the surface of the second lens L2 facing the object side is the third mirror surface S3, and the surface of the second lens L2 facing the image side is the fourth mirror surface S4; the surface of the third lens L3 facing the object side is the fifth mirror surface S5, and the surface of the third lens L3 facing the image side is the sixth mirror surface S6; the surface of the fourth lens L4 facing the object side is the seventh mirror surface S7, and the surface of the fourth lens L4 facing the image side is the eighth mirror surface S8; The surface of the fifth lens L5 facing the object side is the ninth mirror surface S9, and the surface of the fifth lens L5 facing the image side is the tenth mirror surface S10; the surface of the sixth lens L6 facing the object side is the eleventh mirror surface S11, and the surface of the sixth lens L6 facing the image side is the twelfth mirror surface S12; the surface of the seventh lens L7 facing the object side is the thirteenth mirror surface S13, and the surface of the seventh lens L7 facing the image side is the fourteenth mirror surface S14; the surface of the eighth lens L8 facing the object side is the fifteenth mirror surface S15, and the surface of the eighth lens L8 facing the image side is the sixteenth mirror surface S16.

[0033] Moreover, the curvature radii of the first mirror S1, the second mirror S2, the third mirror S3, the fourth mirror S4, the fifth mirror S5, the sixth mirror S6, the eighth mirror S8, the tenth mirror S10, the eleventh mirror S11, the twelfth mirror S12, the thirteenth mirror S13, and the fourteenth mirror S14 are all negative numbers; the curvature radii of the seventh mirror S7, the ninth mirror S9, the fifteenth mirror S15, and the sixteenth mirror S16 are all positive numbers.

[0034] In a preferred embodiment, the specific values ​​of the curvature radius, the clear aperture and the mirror distance between two adjacent mirrors of the first mirror S1 to the sixteenth mirror S16 can refer to Table 2. As shown in Table 2, the curvature radius of the first mirror S1 is -14.6 to -14.58 mm, the clear aperture is 5.94 mm, and the mirror distance between the first mirror S1 and the second mirror S2 is 1.99 to 2.01 mm. The curvature radius of the second mirror S2 is -9.96 to -9.94 mm, the clear aperture is 6.39 mm, and the mirror distance between the second mirror S2 and the third mirror S3 is 0.09 to 0.11 mm. The curvature radius of the third mirror S3 is -28.89 to -28.87 mm, the clear aperture is 6.94 mm, and the mirror distance between the third mirror S3 and the fourth mirror S4 is 2.49 to 2.51 mm.

[0035] The radius of curvature of the fourth mirror S4 is -15.49 to -15.47 mm, the aperture is 7.41 mm, and the mirror distance between the fourth mirror S4 and the fifth mirror S5 is 0.09 to 0.11 mm. The radius of curvature of the fifth mirror S5 is -117.24 to -117.22 mm, the aperture is 7.8 mm, and the mirror distance between the fifth mirror S5 and the sixth mirror S6 is 2.49 to 2.51 mm. The radius of curvature of the sixth mirror S6 is -24.99 to -24.97 mm, the aperture is 8.05 mm, and the mirror distance between the sixth mirror S6 and the seventh mirror S7 is 0.09 to 0.11 mm.

[0036] The seventh mirror S7 has a curvature radius of 79.12 to 79.14 mm, a light aperture of 8.24 mm, and a mirror distance between the seventh mirror S7 and the eighth mirror S8 of 1.98 to 2 mm. The eighth mirror S8 has a curvature radius of -53.23 to -53.21 mm, a light aperture of 8.26 mm, and a mirror distance between the eighth mirror S8 and the ninth mirror S9 of 4.71 to 4.73 mm. The ninth mirror S9 has a curvature radius of 26.71 to 26.73 mm, a light aperture of 8.04 mm, and a mirror distance between the ninth mirror S9 and the tenth mirror S10 of 11.68 to 11.7 mm.

[0037] The curvature radius of the tenth mirror surface S10 is -676.94 to -676.92 mm, the light aperture is 6.783 mm, and the mirror distance between the tenth mirror surface S10 and the eleventh mirror surface S11 is 19.65 to 19.67 mm. The curvature radius of the eleventh mirror surface S11 is -10.72 to -10.7 mm, the light aperture is 3.25 mm, and the mirror distance between the eleventh mirror surface S11 and the twelfth mirror surface S12 is 1.99 to 2.01 mm. The curvature radius of the twelfth mirror surface S12 is -200.48 to -200.46 mm, the light aperture is 3.22 mm, and the mirror distance between the twelfth mirror surface S12 and the thirteenth mirror surface S13 is 1.19 to 1.21 mm.

[0038] The radius of curvature of the thirteenth mirror is -9.93 to -9.91 mm, the aperture is 3.2 mm, and the mirror distance between the thirteenth mirror S13 and the fourteenth mirror S14 is 11.99 to 12.01 mm. The radius of curvature of the fourteenth mirror is -12.7 to -12.68 mm, the aperture is 4.27 mm, and the mirror distance between the fourteenth mirror S14 and the fifteenth mirror S15 is 19.99 to 20.01 mm. The radius of curvature of the fifteenth mirror S15 is 84.1 to 84.12 mm, the aperture is 3.62 mm, and the mirror distance between the fifteenth mirror S15 and the sixteenth mirror S16 is 4.43 to 4.45 mm. The radius of curvature of the sixteenth mirror S16 is 13.94 to 13.96 mm, and the aperture is 3.45 mm.

[0039] Table 2

[0040] Mirror Name Curvature radius (mm) Clear aperture(mm) Mirror distance(mm) First mirror S1 -14.6 to -14.58 5.94 1.99 to 2.01 Second mirror S2 -9.96 to -9.94 6.39 0.09 to 0.11 The third mirror S3 -28.89 to -28.87 6.94 2.49 to 2.51 Fourth mirror S4 -15.49 to -15.47 7.41 0.09 to 0.11 Fifth Mirror S5 -117.24 to -117.22 7.8 2.49 to 2.51 Sixth Mirror S6 -24.99 to -24.97 8.05 0.09 to 0.11 Seventh Mirror S7 79.12 to 79.14 8.24 1.98 to 2 The eighth mirror S8 -53.23 to -53.21 8.26 4.71 to 4.73 Ninth Mirror S9 26.71 to 26.73 8.04 11.68 to 11.7 Tenth Mirror S10 -676.94 to -676.92 6.78 19.65 to 19.67 Mirror 11 S11 -10.72 to -10.7 3.25 1.99 to 2.01 Mirror S12 -200.48 to -200.46 3.22 1.19 to 1.21 Mirror 13 S13 -9.93 to -9.91 3.2 11.99 to 12.01 Mirror 14 S14 -12.7 to -12.68 4.27 19.99 to 20.01 Mirror S15 84.1 to 84.12 3.62 4.43 to 4.45 Mirror S16 13.94 to 13.96 3.45 unlimited

[0041] By referring to the specific parameters and structures of each lens in Table 1 and Table 2 above, the magnification of the deep ultraviolet microscope objective lens can be set to 50 times, the object field of view is 0.6mm, and it has a higher field of view than the conventional commercial 50x microscope objective lens. It can be used with a tube lens with a focal length of 200mm, and the working distance is 13mm, which is larger than the conventional objective lens. The corresponding numerical aperture is large, which is 0.528, which can improve the object field of view and working distance of the deep ultraviolet microscope objective lens, thereby improving the overall performance of the microscope. In addition, it is designed for the wavelength range of 260 to 262nm, and the design value of the resolution within this wavelength range is consistent with the theoretical value; and it is fully independently designed, which solves the problem that the existing 50x objective lens cannot meet many usage requirements in optical detection.

[0042] Specifically, according to the Rayleigh criterion, the resolution limit of the deep ultraviolet microscope objective lens of this embodiment is: 0.61λ / NA=0.61×0.261 / 0.528≈0.302μm. According to the objective lens design MTF calculation, when the MTF value = 0.1, the frequency is about 3145lp / mm, and the resolution = 1 / 3145≈0.318μm. In other words, the theoretical value of the resolution of the deep ultraviolet microscope objective lens of this embodiment is 0.302μm, and the design value is 0.318μm, which are basically the same, and can effectively improve the resolution within a specific ultraviolet wavelength range.

[0043] In a preferred embodiment, the edge or outer frame of the first mirror S1 serves as an aperture stop. The function of the aperture stop is to limit the aperture of the light beam. In addition, it should be noted that the mirror distance from the object plane to the first mirror S1 can be 13 mm. The mirror distance between the sixteenth mirror S16 and the image plane is infinite.

[0044] Figure 2 1 is a point diagram of different fields of view of a deep ultraviolet microscope objective according to an embodiment of the present invention. Figure 2 The focusing condition of light with a wavelength of 261 nm at the focal point under different object plane fields of view is shown. The object plane field of view of field of view (1) is 0.600 mm, the object plane field of view of field of view (2) is 0.300 mm, and the object plane half field of view of field of view (3) is 0.000 mm. The test data are as follows: the RMS radius (root mean square) when the field of view is (1) is 0.106 μm, and the GEO radius (maximum) is 0.353 μm, the RMS radius when the field of view is (2) is 0.027 μm, and the GEO radius is 0.059 μm, and the RMS radius when the field of view is (3) is 0.013 μm, and the GEO radius is 0.018 μm.

[0045] The RMS radius is also called the root mean square spot radius. It is an indicator used to describe the size of the light beam. It is obtained by taking the square root of the light intensity distribution after quadratic averaging. The GEO radius (Geometric Optical Radius) represents the radius of the smallest center circle that contains all the light rays. Specifically, the GEO radius is the smallest center circle radius that can satisfy all the light rays falling within its range. Figure 2 It can be seen that the focused spots of light with a wavelength of 261 nm in different fields of view are all within a small range, indicating that the deep ultraviolet microscope objective lens of this embodiment has an excellent focusing effect. It can be seen that the aberration of the deep ultraviolet microscope objective lens of this embodiment is well controlled.

[0046] Figure 3 4 is a modulation transfer function curve diagram of a deep ultraviolet microscope objective according to an embodiment of the present invention. Figure 3The vertical axis is the modulus of the normalized transfer function, and the horizontal axis is the spatial frequency, in units of lp / mm. The outermost line is the transfer function curve of the system under the diffraction limit. Figure 3 As shown, for the deep ultraviolet microscope objective of this embodiment, when the object plane field of view is 0.600mm, 0.300mm and 0.000mm, the transfer function curves of light with a wavelength of 261nm in the meridian plane and the sagittal plane show that the on-axis field of view transfer function curve and the off-axis field of view transfer function curve are both close to the diffraction limit, indicating that the imaging contrast of the optical system's full field of view is very high and the imaging layering is clear.

[0047] Figure 4 is a field curvature distortion diagram of a deep ultraviolet microscope objective according to an embodiment of the present invention. Figure 4 The left side of the figure is the field curvature diagram, the ordinate is the field of view in the direction of incident light from the objective lens, and the abscissa is the field curvature value in μm. Figure 4 The figure on the right is the distortion diagram, the ordinate is the field of view during imaging, and the abscissa is the distortion amount (%). When testing the field curvature diagram, the data obtained are as follows: the maximum field of view is 4.346 degrees, the sagittal field curvature is 0.0002mm, and the meridian field curvature is 0.0000mm. When testing the distortion diagram, the data obtained are as follows: the maximum field of view is 4.346 degrees, and the maximum distortion amount is 1.3017%. Figure 4 As shown in the figure, the field curvature of light with a wavelength of 261nm in the meridian and sagittal planes is less than 0.06mm, the full field of view is clear, and no additional field curvature is introduced. The full field of view distortion is within 1.5%, the distortion correction is good, and it has excellent large field of view imaging performance.

[0048] The present embodiment also provides a microscope, which includes the deep ultraviolet microscope objective lens of any of the above embodiments. In a specific embodiment, by setting the specific parameters and structures of each lens, the magnification of the deep ultraviolet microscope objective lens can be 50 times, the object field of view is 0.6mm, and it has a higher field of view than the conventional commercial 50x microscope objective lens. It can be used with a tube lens with a focal length of 200mm, and the working distance is 13mm, which is larger than the conventional objective lens. The corresponding numerical aperture is larger, which is 0.528, and can improve the object field of view and working distance of the deep ultraviolet microscope objective lens, thereby improving the overall performance of the microscope. In addition, it is designed for the wavelength range of 260 to 262nm, and the design value of the resolution within this wavelength range is consistent with the theoretical value; and it fully realizes independent design, which solves the problem that the existing 50x objective lens cannot meet many usage requirements in optical detection.

[0049] Those skilled in the art should understand that, unless otherwise specified, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "clockwise", "counterclockwise", etc. in the embodiments of the present invention used to indicate orientation or positional relationships are merely for the convenience of describing and understanding the technical solutions of the present invention, and do not indicate or imply that the referred device or component must have a specific orientation, and therefore should not be understood as limiting the present invention.

[0050] The terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0051] Unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. A person skilled in the art should be able to understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0052] In addition, in the description of this embodiment, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. That is, in the description of this embodiment, the first feature being "above", "above", and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below", or "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0053] In the description of the present embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0054] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A deep ultraviolet microscope objective lens, characterized in that: include: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens are arranged in sequence from the object side to the image side on the same optical axis; The first lens has a concave surface facing the object side and a convex surface facing the image side; the second lens has a concave surface facing the object side and a convex surface facing the image side; the third lens has a concave surface facing the object side and a convex surface facing the image side; the fourth lens has a convex surface facing the object side and a convex surface facing the image side; the fifth lens has a convex surface facing the object side and a concave surface facing the image side; the sixth lens has a concave surface facing the object side and a convex surface facing the image side; the seventh lens has a concave surface facing the object side and a convex surface facing the image side; the eighth lens has a convex surface facing the object side and a concave surface facing the image side.

2. The deep ultraviolet microscope objective lens according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fifth lens, and the seventh lens are all positive meniscus lenses; the fourth lens is a double convex positive lens; and the sixth lens and the eighth lens are all negative meniscus lenses.

3. The deep ultraviolet microscope objective lens according to claim 2, characterized in that: The first lens, the third lens, the fifth lens, and the seventh lens are all made of calcium fluoride; the second lens, the fourth lens, the sixth lens, and the eighth lens are all made of fused quartz.

4. The deep ultraviolet microscope objective lens according to claim 3, characterized in that: The surface of the first lens facing the object is the first mirror surface, and the surface of the first lens facing the image is the second mirror surface; the surface of the second lens facing the object is the third mirror surface, and the surface of the second lens facing the image is the fourth mirror surface; the surface of the third lens facing the object is the fifth mirror surface, and the surface of the third lens facing the image is the sixth mirror surface; The surface of the fourth lens facing the object side is the seventh mirror surface, and the surface of the fourth lens facing the image side is the eighth mirror surface; the surface of the fifth lens facing the object side is the ninth mirror surface, and the surface of the fifth lens facing the image side is the tenth mirror surface; The surface of the sixth lens facing the object is the eleventh mirror surface, and the surface of the sixth lens facing the image is the twelfth mirror surface; the surface of the seventh lens facing the object is the thirteenth mirror surface, and the surface of the seventh lens facing the image is the fourteenth mirror surface; the surface of the eighth lens facing the object is the fifteenth mirror surface, and the surface of the eighth lens facing the image is the sixteenth mirror surface, The curvature radii of the first mirror surface, the second mirror surface, the third mirror surface, the fourth mirror surface, the fifth mirror surface, the sixth mirror surface, the eighth mirror surface, the tenth mirror surface, the eleventh mirror surface, the twelfth mirror surface, the thirteenth mirror surface, and the fourteenth mirror surface are all negative numbers; the curvature radii of the seventh mirror surface, the ninth mirror surface, the fifteenth mirror surface, and the sixteenth mirror surface are all positive numbers.

5. The deep ultraviolet microscope objective lens according to claim 4, characterized in that: The radius of curvature of the first mirror surface is -14.6 to -14.58 mm; The curvature radius of the second mirror surface is -9.96 to -9.94 mm; The radius of curvature of the third mirror surface is -28.89 to -28.87 mm; The curvature radius of the fourth mirror surface is -15.49 to -15.47 mm; The curvature radius of the fifth mirror surface is -117.24 to -117.22 mm; The curvature radius of the sixth mirror surface is -24.99 to -24.97 mm; The curvature radius of the seventh mirror surface is 79.12 to 79.14 mm; The curvature radius of the eighth mirror surface is -53.23 to -53.21 mm; The curvature radius of the ninth mirror surface is 26.71 to 26.73 mm; The curvature radius of the tenth mirror surface is -676.94 to -676.92 mm; The curvature radius of the eleventh mirror surface is -10.72 to -10.7 mm; The curvature radius of the twelfth mirror surface is -200.48 to -200.46 mm; The curvature radius of the thirteenth mirror surface is -9.93 to -9.91 mm; The curvature radius of the fourteenth mirror surface is -12.7 to -12.68 mm; The curvature radius of the fifteenth mirror surface is 84.1 to 84.12 mm; The curvature radius of the sixteenth mirror surface is 13.94 to 13.96 mm.

6. The deep ultraviolet microscope objective lens according to claim 5, characterized in that: The clear aperture of the first mirror is 5.94 mm; The clear aperture of the second mirror is 6.39 mm; The clear aperture of the third mirror is 6.94 mm; The clear aperture of the fourth mirror is 7.41 mm; The light aperture of the fifth mirror is 7.8 mm; The clear aperture of the sixth mirror is 8.05 mm; The light aperture of the seventh mirror is 8.24 mm; The clear aperture of the eighth mirror is 8.26 mm; The clear aperture of the ninth mirror surface is 8.04 mm; The clear aperture of the tenth mirror surface is 6.78 mm; The clear aperture of the eleventh mirror surface is 3.25 mm; The clear aperture of the twelfth mirror surface is 3.22 mm; The clear aperture of the thirteenth mirror surface is 3.2 mm; The clear aperture of the fourteenth mirror surface is 4.27 mm; The light aperture of the fifteenth mirror surface is 3.62 mm; The clear aperture of the sixteenth mirror surface is 3.45 mm.

7. The deep ultraviolet microscope objective lens according to claim 6, characterized in that: The mirror distance between the first mirror surface and the second mirror surface is 1.99 to 2.01 mm; The mirror distance between the second mirror surface and the third mirror surface is 0.09 to 0.11 mm; The mirror distance between the third mirror surface and the fourth mirror surface is 2.49 to 2.51 mm; The mirror distance between the fourth mirror surface and the fifth mirror surface is 0.09 to 0.11 mm; The mirror distance between the fifth mirror surface and the sixth mirror surface is 2.49 to 2.51 mm; The mirror distance between the sixth mirror surface and the seventh mirror surface is 0.09 to 0.11 mm; The mirror distance between the seventh mirror surface and the eighth mirror surface is 1.98 to 2 mm; The mirror distance between the eighth mirror surface and the ninth mirror surface is 4.71 to 4.73 mm; The mirror distance between the ninth mirror surface and the tenth mirror surface is 11.68 to 11.7 mm; The mirror distance between the tenth mirror surface and the eleventh mirror surface is 19.65 to 19.67 mm; The mirror distance between the eleventh mirror surface and the twelfth mirror surface is 1.99 to 2.01 mm; The mirror distance between the twelfth mirror surface and the thirteenth mirror surface is 1.19 to 1.21 mm; The mirror distance between the thirteenth mirror surface and the fourteenth mirror surface is 11.99 to 12.01 mm; The mirror distance between the fourteenth mirror surface and the fifteenth mirror surface is 19.99 to 20.01 mm; The mirror distance between the fifteenth mirror surface and the sixteenth mirror surface is 4.43 to 4.45 mm.

8. The deep ultraviolet microscope objective lens according to claim 7, characterized in that: The deep ultraviolet microscope objective lens is applicable to a wavelength range of 260 to 262 nm, and the focal length of the tube lens that can be used in combination is 200 mm.

9. The deep ultraviolet microscope objective lens according to claim 4, characterized in that: The edge or outer frame of the first mirror serves as an aperture stop.

10. A microscope comprising the deep ultraviolet microscope objective lens according to any one of claims 1 to 9.

Images