A large field of view infinity corrected microtube scope
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2025-07-09
- Publication Date
- 2026-06-26
Smart Images
Figure CN224417111U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microscope tube technology, and in particular to a large field-of-view infinity-corrected microscope tube. Background Technology
[0002] As semiconductor wafer chip sizes become smaller, the required inspection precision becomes increasingly higher. Traditional telecentric lenses cannot meet the imaging inspection requirements. Clear imaging of the microstructure on the chip surface requires imaging through a microscopic system.
[0003] In related technologies, the same device needs to achieve imaging and positioning detection for different products with different requirements, which in turn requires different magnification. Traditional telecentric lenses are mostly fixed-focus lenses and cannot achieve detection and imaging at different magnifications.
[0004] Therefore, it is necessary to propose a large-field-of-view infinity-corrected microscope tube, which can be used with an infinity-corrected microscope objective to achieve magnification at different magnifications, and this has become an important technical problem that needs to be solved. Utility Model Content
[0005] This application provides a large field-of-view infinity-corrected microscope, which aims to solve the problem in the prior art that the same device needs to achieve imaging and positioning detection for different products with different requirements, thus requiring different magnifications. Traditional telecentric lenses are mostly fixed-focus lenses, which cannot achieve detection and imaging at different magnifications.
[0006] To achieve the above objectives, this application proposes a large field-of-view infinity-corrected microscope, comprising an aperture and an image plane arranged coaxially, and a first lens, a second lens, a third lens, and a fourth lens arranged coaxially between the aperture and the image plane; the first lens has negative optical power and a focal length of -1379.945 mm; the second lens has positive optical power and a focal length of 210.525 mm; the third lens has positive optical power and a focal length of 111.034 mm; and the fourth lens has negative optical power and a focal length of -93.448 mm.
[0007] In some embodiments, the first lens includes an S11 surface and an S12 surface arranged sequentially from the aperture stop to the image plane. Both the S11 surface and the S12 surface protrude toward the image plane, and both the S11 surface and the S12 surface are spherical.
[0008] In some embodiments, the second lens is a cemented doublet lens, which includes a first sub-lens and a second sub-lens. The second lens includes surfaces S21, S22 and S23 arranged sequentially from the aperture stop to the image plane. Surface S22 is the cemented surface of the first sub-lens and the second sub-lens. Surfaces S22 and S23 both bulge toward the image plane, and surface S21 bulges toward the aperture stop. Surfaces S21, S22 and S23 are all spherical surfaces.
[0009] In some embodiments, the third lens includes an S31 surface and an S32 surface arranged sequentially from the aperture stop to the image plane. The S31 surface protrudes from the aperture stop, and the S32 surface protrudes from the image plane. The S31 surface and the S32 surface are spherical.
[0010] In some embodiments, the fourth lens includes an S41 surface and an S42 surface arranged sequentially from the aperture stop to the image plane, with the S41 surface and the S42 surface protruding from the aperture stop.
[0011] In some embodiments, the center thickness of the first lens is 7.603 mm;
[0012] The center thickness of the second lens is 21.976 mm;
[0013] The center thickness of the third lens is 12.864 mm;
[0014] The center thickness of the fourth lens is 8.071 mm.
[0015] This application proposes a large field-of-view infinity-corrected microscope, comprising an aperture and an image plane arranged coaxially, and a first lens, a second lens, a third lens, and a fourth lens arranged coaxially between the aperture and the image plane; the first lens has negative optical power and a focal length of -1379.945 mm; the second lens has positive optical power and a focal length of 210.525 mm; the third lens has positive optical power and a focal length of 111.034 mm; and the fourth lens has negative optical power and a focal length of -93.448 mm. The large-field-of-view infinity-corrected microscope tube of this application can be adapted to a large-field-of-view infinity-corrected objective lens, thereby enabling large target surface inspection. The magnification of the microscope composed of the large-field-of-view infinity-corrected microscope tube and the infinity-corrected objective lens is determined by the ratio of the focal length of the tube and the focal length of the infinity-corrected objective lens. Different focal lengths of infinity-corrected objectives paired with the same large-field-of-view infinity-corrected microscope tube can meet the magnification requirements of different products. The aforementioned large-field-of-view infinity-corrected microscope tube can be paired with infinity-corrected objectives of different focal lengths to meet the different magnification requirements of different products. In the assembled large-field-of-view infinity-corrected microscope tube structure, different magnifications can be achieved simply by switching between infinity-corrected objectives of different focal lengths using the nose wheel assembly. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:
[0017] Figure 1 This is a schematic diagram of the structure of a large field-of-view infinite distance corrected microscope according to an embodiment of this application;
[0018] Figure 2 This is a schematic diagram of a large field-of-view infinity-corrected microscope with an aperture and an image plane in one embodiment of this application.
[0019] Figure 3 This is a modulation transfer function curve diagram from one embodiment of this application;
[0020] Figure 4 This is a field curvature curve diagram from one embodiment of this application;
[0021] Figure 5 This is a distortion curve diagram from one embodiment of this application;
[0022] Figure 6 This is an axial aberration curve diagram from one embodiment of this application;
[0023] Figure 7 This is a vertical axis color difference curve diagram in one embodiment of this application;
[0024] Figure 8 This is a relative illumination curve diagram from one embodiment of this application.
[0025] In the diagram: aperture 00, first lens 10, second lens 20, first sub-lens 201, second sub-lens 202, third lens 30, fourth lens 40, image plane 01. Detailed Implementation
[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0027] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0028] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.
[0029] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.
[0030] See Figure 1 and Figure 2 As shown, this application proposes a large field-of-view infinity-corrected microscope, including an aperture 00 and an image plane 01 arranged coaxially, and a first lens 10, a second lens 20, a third lens 30, and a fourth lens 40 arranged coaxially between the aperture 00 and the image plane 01; the first lens 10 has negative optical power and a focal length of -1379.945 mm; the second lens 20 has positive optical power and a focal length of 210.525 mm; the third lens 30 has positive optical power and a focal length of 111.034 mm; the fourth lens 40 has negative optical power and a focal length of -93.448 mm.
[0031] Various optical accessories in the microscope, such as wavelength splitters, energy splitters, and beam splitters, can be placed in the parallel beam space between the infinity-corrected objective lens and the large-field-of-view infinity-corrected microscope lens. Since the imaging beam is not interfered with by the optical accessories, the image quality is not compromised.
[0032] Among them, the first lens 10 is a meniscus negative lens, the second lens 20 is a cemented doublet lens, the third lens 30 is a biconvex lens, and the fourth lens 40 is a meniscus negative lens; the second lens 20 is formed by cementing a biconvex lens and a meniscus negative lens together.
[0033] Specifically, the large-field-of-view infinity-corrected microscope tube in this application can be adapted to an infinity-corrected objective lens, thereby enabling large target surface detection. The magnification of the microscope composed of the large-field-of-view infinity-corrected microscope tube and the infinity-corrected objective lens is determined by the ratio of the focal length of the tube and the focal length of the infinity-corrected objective lens. Different focal lengths of infinity-corrected objectives paired with the same large-field-of-view infinity-corrected microscope tube can meet the magnification requirements of different products. The aforementioned large-field-of-view infinity-corrected microscope tube can be paired with infinity-corrected objectives of different focal lengths to meet the different magnification requirements of different products. In the assembled large-field-of-view infinity-corrected microscope tube structure, different magnifications can be achieved simply by switching between infinity-corrected objectives of different focal lengths using the nose wheel assembly.
[0034] Among them, the nose wheel assembly for microscopes is a mature existing technology, and no specific restrictions will be imposed on the nose wheel assembly here.
[0035] See Figure 1 and Figure 2 As shown, in some embodiments, the first lens, second lens, third lens, and fourth lens are all spherical or planar. The first lens 10 includes surfaces S11 and S12 sequentially arranged from the aperture stop 00 to the image plane 01. Surfaces S11 and S12 both convex towards the image plane 01, and both surfaces S11 and S12 are spherical. The second lens 20 is a cemented doublet lens, including a first lens 201 and a second lens 202. The second lens 20 also includes surfaces S21, S22, and S23 sequentially arranged from the aperture stop 00 to the image plane 01. Surface S22 is the cemented surface of the first lens 201 and the second lens 202. Surfaces S22 and S23 both convex towards the image plane 01, while surface S21 convexes towards the aperture stop 00. Surfaces S21, S22, and S23 are all spherical. The third lens 30 includes surfaces S31 and S32 arranged sequentially from the aperture stop 00 to the image plane 01. Surface S31 protrudes from the aperture stop 00, and surface S32 protrudes from the image plane 01. Surfaces S31 and S32 are spherical. The fourth lens 40 includes surfaces S41 and S42 arranged sequentially from the aperture stop 00 to the image plane 01. Surfaces S41 and S42 protrude from the aperture stop 00. The center thickness of the first lens 10 is 7.603 mm; the center thickness of the second lens 20 is 21.976 mm; the center thickness of the third lens 30 is 12.864 mm; and the center thickness of the fourth lens 40 is 8.071 mm.
[0036] Table 1 shows the specific parameters of each plane in a large field-of-view infinity-corrected microscope:
[0037]
[0038] Table 1
[0039] See Figure 3As shown, in this embodiment, the MTF value of the large field-of-view infinitely corrected microscope is close to the diffraction limit. In the figure, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. Figure 3 This indicates the lens imaging modulation at different spatial frequencies in each field of view.
[0040] See Figure 4 As shown, in this embodiment, the field curvature of the meridional and sagittal image planes of the large field-of-view infinite correction microscope is controlled within ±0.29 mm. The horizontal axis in the figure represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). Figure 4 It indicates the degree of curvature of light of different wavelengths in the meridional and sagittal planes.
[0041] See Figure 5 As shown in this embodiment, the distortion rate of the large field-of-view infinite correction microscope at different wavelengths is less than 0.13% across the entire field of view. The horizontal axis in the figure represents the distortion percentage, and the vertical axis represents the half field of view angle (unit: °). Figure 5 This indicates the distortion rate at different wavelengths.
[0042] See Figure 6 As shown, in this embodiment, the axial aberration offset of the large field-of-view infinite correction microscope is controlled within 0.16 mm. In the figure, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. Figure 6 This represents the aberrations of each wavelength along the optical axis at the imaging plane.
[0043] See Figure 7 As shown, in this embodiment, the transverse chromatic aberration of the longest and shortest wavelengths of the large field-of-view infinity-corrected microscope is controlled within ±1.4 μm. The horizontal axis in the figure represents the transverse chromatic aberration value (unit: μm) of each wavelength relative to the center wavelength, and the vertical axis represents the actual image height. Figure 7 This represents the chromatic difference of each wavelength relative to the center wavelength (0.53µm) at different image heights on the imaging plane.
[0044] See Figure 8 As shown, in this embodiment, the relative illumination value of the optical lens of the large field-of-view infinity-corrected microscope is still greater than 97% at the maximum image height. In the figure, the horizontal axis represents image height (unit: mm), and the vertical axis represents relative illumination (unit: %). Figure 8 This represents the relative illumination value at different image heights on the imaging plane.
[0045] In summary, the large field-of-view infinity-corrected microscope has a focal length f of 200mm, a maximum image height radius of 20mm, an entrance pupil diameter of 12mm, a maximum half-incident angle of 5.703°, a total system length of 351.327mm, a numerical aperture NA of 0.03, and a full-field MTF close to the diffraction limit.
[0046] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.
Claims
1. A large field-of-view infinity-corrected microscope, comprising an aperture stop (00) and an image plane (01) arranged coaxially, characterized in that, It also includes a first lens (10), a second lens (20), a third lens (30), and a fourth lens (40) arranged coaxially in sequence and located between the aperture stop (00) and the image plane (01); The first lens (10) has negative optical power, and the focal length of the first lens (10) is -1379.945 mm; The second lens (20) has positive optical power and the focal length of the second lens (20) is 210.525 mm; The third lens (30) has positive optical power and the focal length of the third lens (30) is 111.034 mm; The fourth lens (40) has negative optical power and a focal length of -93.448 mm.
2. The large field-of-view infinity-corrected microscope according to claim 1, characterized in that, The first lens (10) includes an S11 surface and an S12 surface arranged sequentially from the aperture stop (00) to the image plane (01). Both the S11 surface and the S12 surface protrude toward the image plane (01), and both the S11 surface and the S12 surface are spherical.
3. The large field-of-view infinity-corrected microscope according to claim 1, characterized in that: The second lens (20) is a cemented doublet lens. The second lens (20) includes a first sub-lens (201) and a second sub-lens (202). The second lens (20) includes surfaces S21, S22 and S23 arranged sequentially from the aperture stop (00) to the image plane (01). Surface S22 is the cemented surface of the first sub-lens (201) and the second sub-lens (202). Surfaces S22 and S23 both protrude toward the image plane (01). Surface S21 protrudes toward the aperture stop (00). Surfaces S21, S22 and S23 are all spherical surfaces.
4. A large field-of-view infinity-corrected microscope according to claim 1, characterized in that: The third lens (30) includes an S31 surface and an S32 surface arranged sequentially from the aperture stop (00) to the image plane (01). The S31 surface protrudes from the aperture stop (00), and the S32 surface protrudes from the image plane (01). The S31 surface and the S32 surface are spherical.
5. A large field-of-view infinity-corrected microscope according to claim 1, characterized in that: The fourth lens (40) includes an S41 surface and an S42 surface arranged sequentially from the aperture stop (00) to the image plane (01), and the S41 surface and the S42 surface protrude from the aperture stop (00).
6. A large field-of-view infinity-corrected microscope according to claim 1, characterized in that, The center thickness of the first lens (10) is 7.603 mm; The center thickness of the second lens (20) is 21.976 mm; The center thickness of the third lens (30) is 12.864 mm; The center thickness of the fourth lens (40) is 8.071 mm.