A high optical flux long working distance confocal microscope objective
By optimizing the lens combination design, the limitations of field of view, resolution, and working distance in optical microscope systems have been solved, achieving high-throughput imaging with high resolution, large field of view, and long working distance, with imaging effect reaching the diffraction limit.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAZHONG UNIV OF SCI & TECH
- Filing Date
- 2025-05-20
- Publication Date
- 2026-07-10
AI Technical Summary
In existing optical microscope systems, the field of view, resolution, and working distance are mutually restrictive, making it difficult to achieve high-throughput imaging that combines high resolution and a large field of view.
Design a confocal microscope objective with high optical throughput and long working distance. By setting up a first lens group with positive optical power, a second lens group with negative optical power, and a third lens group with positive optical power, the lens combination is optimized to increase the numerical aperture, extend the working distance, and correct aberrations.
It achieves high-quality imaging with a 12mm field of view, a 0.5 numerical aperture, and a 17.7mm working distance, covering the imaging band from 420nm to 680nm, making it suitable for most application scenarios, and the imaging effect reaches the diffraction limit.
Smart Images
Figure CN120491297B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of microscopy, and more particularly to a confocal microscope objective with high optical throughput and long working distance. Background Technology
[0002] Laser scanning confocal microscopy (LSCM) is one of the most widely used fluorescence microscopy tools in biological research, characterized by high resolution, high sensitivity, and high magnification. The key technology of LSCM lies in imaging only one point in space (the focal point) at a time, and then using computer-controlled point-by-point scanning to form a two-dimensional or three-dimensional image of the sample. During this process, light signals from outside the focal plane do not interfere with the imaging, thus greatly improving the clarity and detail resolution of the microscope image. It is commonly used in fields such as optical sectioning of tissues, three-dimensional image reconstruction, and semiconductor and micro / nano manufacturing inspection.
[0003] Laser confocal microscopy employs a point-scan imaging method, a characteristic that means its images are generated point-by-point, resulting in a relatively slow imaging speed. High numerical aperture (NA) and high-throughput objectives with large fields of view can collect more sample information, effectively reducing the number of mechanical movements of the objective or sample, thus significantly improving imaging efficiency. With the continuous expansion of in vivo imaging applications, the demand for larger fields of view, longer working distances, and high-speed, high-resolution imaging is increasing, leading to the development of multi-channel, large-field-of-view confocal microscopes. In optical systems, a larger numerical aperture results in higher objective resolution, but usually comes with a shorter working distance because a larger incident angle collects more light. However, increasing the NA often reduces the field of view because high NA objectives require more complex optical corrections, thus limiting the image plane size.
[0004] In 2016, McConnell et al. developed an optical lens system in their article "Anovel optical microscope for imaging largeembryos and tissue volumes with sub-cellular resolution throughout" for 3D imaging of objects up to 6 mm wide and 3 mm thick.
[0005] In 2017, Shaun Pacheco et al. proposed the development of a novel high-resolution, high-speed, long-working-distance, large-field-of-view confocal fluorescence microscope in their article "High resolution, high speed, long working distance, large field of view confocal fluorescence microscope". Its numerical aperture (NA) reached 0.5, with a 3mm × 3mm field of view and a 12mm working distance.
[0006] In 2019, Jingtao Fan et al. proposed a real-time, ultra-large-scale, high-resolution (RUSH) imaging platform in their article "Video-rate imaging of biological dynamics at centimetre scale and micrometre resolution," with an objective lens of 10×12mm. 2 The field of view is 0.35, and the numerical aperture is 0.35, which is used for imaging in the visible light band.
[0007] It is evident that in optical microscope systems, the field of view, resolution, and working distance are mutually restrictive. Therefore, achieving high-throughput imaging with both high resolution and a large field of view remains one of the key research issues. Summary of the Invention
[0008] Based on the problems existing in the prior art, the present invention aims to solve the technical problem that in the existing optical microscope system, the field of view, resolution and working distance are mutually restrictive, so it is difficult to achieve high-throughput imaging with both high resolution and large field of view.
[0009] This invention provides a high optical throughput, long working distance confocal microscope objective, comprising a first lens group with positive optical power and a second lens group with negative optical power arranged sequentially along the light transmission direction, wherein...
[0010] The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the light transmission direction. The first lens is a negative lens, used to extend the working distance of the objective lens and correct part of the spherical aberration and field curvature. The combination of the second lens, the third lens, and the fourth lens has positive optical power, used to focus light rays, so that the objective lens obtains a larger numerical aperture.
[0011] The second lens group includes a sixth lens and a seventh lens arranged sequentially along the light transmission direction. The combination of the sixth lens and the seventh lens has negative optical power, which is used to increase the beam aperture while reducing the incident beam angle, thereby reducing the generation of object image aberration.
[0012] According to one embodiment of the present invention, the optical power φ1 of the first lens group has a value range of 0.018 < φ1 < 0.03, and the optical power φ2 of the second lens group has a value range of -0.009 < φ2 < -0.008.
[0013] According to one embodiment of the present invention, the optical power of the first lens ranges from -0.01 to -0.02; the optical power of the combination of the second lens, the third lens and the fourth lens ranges from 0.02 to 0.03.
[0014] According to one embodiment of the present invention, the optical power of the combination of the sixth lens and the seventh lens ranges from -0.03 to -0.02.
[0015] According to one embodiment of the present invention, the first lens group further includes a fifth lens disposed on the side of the fourth lens away from the first lens, the fifth lens being used to correct field curvature and collect light beams so that the objective lens obtains a larger numerical aperture.
[0016] According to one embodiment of the present invention, the second lens group further includes an eighth lens disposed on the side of the seventh lens away from the sixth lens, the eighth lens having positive optical power to reduce the aperture of the incident beam, thereby facilitating aberration correction.
[0017] According to one embodiment of the present invention, the optical power of the eighth lens ranges from 0.007 to 0.008.
[0018] According to an embodiment of the present invention, the high optical throughput and long working distance confocal microscope objective further includes a third lens group with positive optical power disposed between the first lens group and the second lens group, the third lens group being used to correct spherical aberration, field curvature and on-axis chromatic aberration.
[0019] According to one embodiment of the present invention, the third lens group includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens arranged sequentially along the light transmission direction. The combination of the tenth and eleventh lenses has positive optical power to correct part of the axial chromatic aberration and spherical aberration; the combination of the twelfth and thirteenth lenses has negative optical power to correct part of the axial chromatic aberration and spherical aberration; and the combination of the fourteenth and fifteenth lenses has negative optical power to correct part of the axial chromatic aberration and spherical aberration.
[0020] According to one embodiment of the present invention, the optical power φ3 of the third lens group is in the range of 0.008 < φ3 < 0.012.
[0021] The beneficial effects of this invention are:
[0022] This invention provides a high-optical-throughput, long-working-distance confocal microscope objective with a 12mm field of view, a numerical aperture of 0.5, a working distance of up to 17.7mm, and an imaging band covering 420nm to 680nm, which covers the visible light band. It is suitable for most application scenarios and achieves the diffraction limit across the entire field of view, ensuring high-quality imaging. It achieves excellent imaging performance while balancing a large field of view, high resolution, and long working distance. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments or prior art, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the structure of a high optical throughput, long working distance confocal microscope objective provided in an embodiment of the present invention;
[0025] Figure 2 This is a schematic diagram of the modulation transfer function curve of a high optical throughput and long working distance confocal microscope objective provided in an embodiment of the present invention;
[0026] Figure 3 This is a dot plot of a high optical throughput, long working distance confocal microscope objective provided in an embodiment of the present invention;
[0027] Figure 4 This is a schematic diagram of the axial chromatic aberration curve of a confocal microscope objective with high optical throughput and long working distance provided in an embodiment of the present invention;
[0028] Reference numerals: G1, first lens group; G11, first lens; G12, second lens; G13, third lens; G14, fourth lens; G15, fifth lens; G2, second lens group; G21, sixth lens; G22, seventh lens; G23, eighth lens; G24, ninth lens; G3, third lens group; G31, tenth lens; G32, eleventh lens; G33, twelfth lens; G34, thirteenth lens; G35, fourteenth lens; G36, fifteenth lens; G37, sixteenth lens; G38, seventeenth lens. Detailed Implementation
[0029] The following descriptions of the embodiments are made with reference to the accompanying illustrations to illustrate specific embodiments in which the invention can be implemented.
[0030] This invention provides a high optical throughput and long working distance confocal microscope objective, the structure of which is as follows: Figure 1 As shown, this includes along the direction of light transmission ( Figure 1 The following three lens groups are arranged sequentially from right to left: a first lens group G1 with positive optical power, a third lens group G3 with positive optical power, and a second lens group G2 with negative optical power. The first lens group G1 is located closer to the object side, and the second lens group G2 is located closer to the image side. The optical power φ1 of the first lens group G1 has a value range of 0.018 < φ1 < 0.03, which is used to collect the light beam, form a high numerical aperture, and correct spherical aberration, coma, and on-axis chromatic aberration. The optical power φ2 of the second lens group G2 has a value range of -0.009 < φ2 < -0.008, which is used to correct spherical aberration, coma, and field curvature. The optical power φ3 of the third lens group G3 has a value range of 0.008 < φ3 < 0.012, which is used to correct spherical aberration, field curvature, and on-axis chromatic aberration.
[0031] In this design, the objective lens has the following design parameters: a field of view of 12mm, a numerical aperture of 0.5, and a working distance of up to 17.7mm.
[0032] Exemplary first lens group G1
[0033] The first lens group G1 includes a first lens G11, a second lens G12, a third lens G13, a fourth lens G14, and a fifth lens G15 arranged sequentially along the light transmission direction. The first lens G11 is a negative lens used to extend the working distance of the objective lens and correct part of the spherical aberration and field curvature. The combination of the second lens G12, the third lens G13, and the fourth lens G14 has positive optical power to focus light and enable the objective lens to obtain a larger numerical aperture. The fifth lens G15 is used to correct field curvature and collect the light beam to enable the objective lens to obtain a larger numerical aperture.
[0034] Specifically, the optical power of the first lens G11 ranges from -0.01 to -0.02; the optical power of the combination of the second lens G12, the third lens G13 and the fourth lens G14 ranges from 0.02 to 0.03.
[0035] More specifically, the focal lengths of the first lens G11, the second lens G12, the third lens G13, the fourth lens G14, and the fifth lens G15 are -75 mm. <f11<-70、80<f12<90、330<f13<340、70<f14<80、-5200<f15<-5100。
[0036] Furthermore, the refractive indices of the first lens G11, the second lens G12, the third lens G13, the fourth lens G14, and the fifth lens G15 are each 1.66. <nd11<1.7、1.9<nd12<1.93、1.9<nd13<1.93、1.55<nd14<1.6、1.4<nd15<1.45。
[0037] Exemplary second lens group G2
[0038] The second lens group G2 includes a ninth lens G24, a sixth lens G21, a seventh lens G22, and an eighth lens G23 arranged sequentially along the light transmission direction. The combination of the sixth lens G21 and the seventh lens G22 has negative optical power, used to increase the beam aperture while reducing the incident beam angle, thereby reducing the generation of object aberrations. The eighth lens G23 has positive optical power, used to reduce the incident beam aperture, thus facilitating aberration correction. The ninth lens G24 is used to correct part of spherical aberration and field curvature.
[0039] Specifically, the optical power of the combination of the sixth lens G21 and the seventh lens G22 ranges from -0.03 to -0.02; the optical power of the eighth lens G23 ranges from 0.007 to 0.008.
[0040] More specifically, the focal lengths of the ninth lens G24, the sixth lens G21, the seventh lens G22, and the eighth lens G23 are -288 nm. <f24<-280、-260<f21<-255、-53<f22<-49、139<f23<143;
[0041] Furthermore, the refractive indices of the ninth lens G24, the sixth lens G21, the seventh lens G22, and the eighth lens G23 are respectively 1.8. <nd24<1.86、1.6<nd21<1.65、1.7<nd22<1.75、1.8<nd23<1.9。
[0042] Exemplary third lens group G3
[0043] The third lens group G3 includes a tenth lens G31, an eleventh lens G32, a twelfth lens G33, a thirteenth lens G34, a sixteenth lens G37, a fourteenth lens G35, a fifteenth lens G36, and a seventeenth lens G38 arranged sequentially along the light transmission direction. The combination of the tenth lens G31 and the eleventh lens G32 has positive optical power to correct some axial chromatic aberration and spherical aberration; the combination of the twelfth lens G33 and the thirteenth lens G34 has negative optical power to correct some axial chromatic aberration and spherical aberration; and the combination of the fourteenth lens G35 and the fifteenth lens G36 has negative optical power to correct some axial chromatic aberration and spherical aberration. The sixteenth lens G37 and the seventeenth lens G38 are both used to correct some spherical aberration.
[0044] Specifically, the optical power of the combination of the fourteenth lens G35 and the fifteenth lens G36 ranges from -0.004 to -0.003; the optical power of the combination of the twelfth lens G33 and the thirteenth lens G34 ranges from -0.007 to -0.006; and the optical power of the combination of the tenth lens G31 and the eleventh lens G32 ranges from 0.004 to 0.005.
[0045] More specifically, the focal lengths of the tenth lens G31, the eleventh lens G32, the twelfth lens G33, the thirteenth lens G34, the sixteenth lens G37, the fourteenth lens G35, the fifteenth lens G36, and the seventeenth lens G38 are respectively 130. <f31<140、-345<f32<-340、-60<f33<-50、90<f34<100、90<f37<100、-73<f35<-65、90<f36<100、185<f38<190。
[0046] Furthermore, the refractive indices of the tenth lens G31, the eleventh lens G32, the twelfth lens G33, the thirteenth lens G34, the sixteenth lens G37, the fourteenth lens G35, the fifteenth lens G36, and the seventeenth lens G38 are respectively 1.4. <nd31<1.45、1.6<nd32<1.65、1.6<nd33<1.65、1.55<nd34<1.6、1.55<nd37<1.6、1.94<nd35<2、1.55<nd36<1.6、1.55<nd38<1.6。
[0047] exist Figure 1 The surfaces of all lenses (35 in total) are numbered from left to right, and the range of the radius of curvature for each numbered surface is as follows:
[0048] 95 < c1 < 100, 485 < c2 < 495, -215 < c3 < -205, 45 < c4 < 50, 80 < c5 < 90, 50 < c6 < 60, -40 < c7 < -50, -60 < c8 < -50, 1380 < c9 < 1390, -120 < c10 < -110, 290 < c12 < 300, -70 < C13 < -60, -60 < c14 < -50, -470 < c15 < -460, 190 < c16 < 200, -80 < c17 < -70, 140 < c18 < 150, -90 < c19 < -80, -90 < c20 < -80, 60 < c21 < 70, 110 < c22 < 120, 60 < c23 < 70, 70 < c24 < 80, -280 < c25 < -290, 40 < c26 < 50, 40 < c27 < 50, 50 < c28 < 60, -230 < c29 < -220, 110 < c30 < 120, 180 < c31 < 190, 30 < c32 < 40, 60 < c33 < 70, 40 < c34 < 50, 20 < c35 < 30。
[0049] From left to right, the air gaps between adjacent two lenses are successively as follows:
[0050] 40 < d1 < 50, 1 < d2 < 5, 8 < d3 < 13, 0.3 < d4 < 1, 1 < d5 < 2, 1 < d6 < 2, 1 < d7 < 2, 1 < d8 < 2, 0.5 < d9 < 2, 4 < d10 < 5, 0.5 < d11 < 1.5, 1 < d12 < 2, 4 < d13 < 5, 0.5 < d14 < 1.5, 0.5 < d15 < 1.5, 0.5 < d16 < 1.5, 15 < d17 < 20, where d17 refers to the distance from the rightmost lens to the object surface.
[0051] Table 1 gives the relevant parameters of all lens surfaces in a specific embodiment of the present invention:
[0052] Table 1 Relevant Parameters of Lens Surfaces
[0053]
[0054]
[0055] In Table 1, the surface represented by serial number 11 is the aperture surface. The aperture surface refers to a specific position on the focal plane of the objective lens, and usually an aperture is installed. An aperture is an optical element used to control the amount and angle of the light beam entering the objective lens, thereby affecting the quality and characteristics of imaging.
[0056] Figure 2This is a schematic diagram of the modulation transfer function (MTF) curve of the objective lens. The horizontal axis represents the spatial frequency, with the unit being "line pairs / millimeters" (LP / MM). The vertical axis represents the MTF value, which ranges from 0 to 1. The larger the value, the clearer the image. Figure 2 In the example, the objective lens has a half field of view of 6mm. To ensure the imaging quality of the entire field of view, five fields of view are selected at equal intervals: 0mm, 1.48mm, 2.96mm, 4.43mm, and 6mm. It can be seen that the MTF curves of each field of view closely follow the diffraction limit curve, indicating that the imaging quality of the system is close to the diffraction limit.
[0057] Figure 3 The dot plot of the objective lens shows the concentration of the light spot on the imaging plane, reflecting the lens's resolution capability. Figure 3 In the middle, the half-image height at the image plane is 6mm, so the full field of view of this scheme can reach 12mm; Figure 3 The visible light spot falls primarily within the Airy disk, further validating the high-resolution imaging capability of the objective lens.
[0058] Figure 4 This is a schematic diagram of the axial chromatic aberration curve. The vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the deviation of the imaging position. The closer the curve is to the center, the smaller the deviation. Figure 4 As can be seen from the image, the imaging band of this scheme covers 420nm to 680nm; Figure 4 The visible axial chromatic aberration has been effectively corrected, ensuring color consistency and accuracy in imaging.
[0059] In summary, the present invention provides a high optical throughput and long working distance confocal microscope objective with a 12mm field of view, a numerical aperture of 0.5, a working distance of up to 17.7mm, and an imaging band covering 420nm to 680nm, which covers the visible light band. It is suitable for most application scenarios and achieves the diffraction limit across the entire field of view, ensuring high-quality imaging. It achieves excellent imaging performance while balancing a large field of view, high resolution, and long working distance.
[0060] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.
Claims
1. A confocal microscope objective with high optical throughput and long working distance, characterized in that, It includes a first lens group (G1) with positive optical power, a second lens group (G2) with negative optical power, and a third lens group (G3) with positive optical power, which are arranged in sequence along the optical transmission direction. Among them, the total number of lenses with optical power in the microscope objective is 17; The first lens group (G1) includes a first lens (G11), a second lens (G12), a third lens (G13), a fourth lens (G14), and a fifth lens, which are arranged in sequence along the optical transmission direction. Among them, the first lens (G11) is a negative lens, which is used to extend the working distance of the objective and correct part of the spherical aberration and field curvature. The value range of the focal length f11 of the first lens (G11) is: -75mm < f11 < -70mm; The combination of the second lens (G12), the third lens (G13), and the fourth lens (G14) has positive optical power, which is used to focus light so that the objective can obtain a larger numerical aperture; The fifth lens (G15) is used to correct the field curvature and collect the light beam so that the objective can obtain a larger numerical aperture; The second lens group (G2) includes a ninth lens (G24), a sixth lens (G21), a seventh lens (G22), and an eighth lens (G23), which are arranged in sequence along the optical transmission direction. The combination of the sixth lens (G21) and the seventh lens (G22) has negative optical power, which is used to expand the beam aperture while reducing the incident beam angle, thereby reducing the generation of objective aberration; The eighth lens (G23) has positive optical power, which is used to reduce the incident beam aperture, thereby facilitating the correction of aberration; The ninth lens G24 is used to correct part of the spherical aberration and field curvature; The third lens group (G3) is used to correct spherical aberration, field curvature, and axial chromatic aberration; The third lens group (G3) includes a tenth lens (G31), an eleventh lens (G32), a twelfth lens (G33), a thirteenth lens (G34), a sixteenth lens (G37), a fourteenth lens (G35), a fifteenth lens (G36), and a seventeenth lens (G38), which are arranged in sequence along the optical transmission direction. Among them, the combination of the tenth lens (G31) and the eleventh lens (G32) has positive optical power, which is used to correct part of the axial chromatic aberration and spherical aberration; The combination of the twelfth lens (G33) and the thirteenth lens (G34) has negative optical power, which is used to correct part of the axial chromatic aberration and spherical aberration; The combination of the fourteenth lens (G35) and the fifteenth lens (G36) has negative optical power, which is used to correct part of the axial chromatic aberration and spherical aberration; The sixteenth lens (G37) and the seventeenth lens (G38) are both used to correct part of the spherical aberration.
2. The high optical throughput, long working distance confocal microscope objective according to claim 1, characterized in that, The value range of the optical power φ1 of the first lens group (G1) is 0.018 < φ1 < 0.03, and the value range of the optical power φ2 of the second lens group (G2) is -0.009 < φ2 < -0.
008.
3. The high optical throughput, long working distance confocal microscope objective according to claim 1, characterized in that, The optical power of the first lens (G11) ranges from -0.01 to -0.02; the optical power of the combination of the second lens (G12), the third lens (G13), and the fourth lens (G14) ranges from 0.02 to 0.
03.
4. The high optical throughput, long working distance confocal microscope objective according to claim 1, characterized in that, The optical power of the combination of the sixth lens (G21) and the seventh lens (G22) ranges from -0.03 to -0.
02.
5. The high optical throughput, long working distance confocal microscope objective according to claim 1, characterized in that, The optical power of the eighth lens (G23) ranges from 0.007 to 0.
008.
6. The high optical throughput, long working distance confocal microscope objective according to claim 5, characterized in that, The optical power φ3 of the third lens group (G3) has a range of 0.008 < φ3 < 0.012.