Immersion objective, optical system and detection method

Abstract

An immersion objective, an optical system and a detection method. The immersion objective comprises, in the direction from an object side (S) to an image side, a first lens group (G1) with positive refractive power, at least one group of negative refractive power lens groups (G5, G6) and an immersion medium (m) located on the object side (S) of the first lens group (G1) and at least partially immersing the first lens group (G1), the working distance S0 of the immersion medium (m) between the first lens group (G1) and the object side (S) and the focal length F of the immersion objective satisfy the condition formula 0 obj S0 / F obj ≤0.16. By means of the cooperation of multiple groups of lenses, the immersion objective has a smaller size and a smaller mass in a relatively compact size range, and a large field of view, high resolution and low distortion are achieved, and the optical performance of the immersion objective is improved.

Description

Technical Field

[0001] This invention relates to the field of optics, and in particular to an immersion objective, an optical system, and a detection method. Background Technology

[0002] Large-field apochromatic objectives with near-diffraction-limited imaging quality typically require a dozen or more lenses to balance the various aberrations introduced by the large field of view and large numerical aperture (NA). This results in a complex objective structure and makes optical design under certain size and weight constraints extremely difficult. Furthermore, the manufacturing and assembly of these objectives place industry-leading demands on component machining tolerances, objective assembly precision, and system testing accuracy. This necessitates expensive manufacturing, assembly, and testing equipment or modification equipment, as well as highly experienced engineers and operators.

[0003] The field of view of a microscope, which is the object area that can be acquired per unit time, is the largest object area when the size of the object is fixed. This means that fewer tests are needed to completely detect the object, saving time and number of operations. The numerical aperture and working wavelength of a microscope determine its resolution. The numerical aperture NA = n*sinθ, where n is the refractive index of the object medium and θ is the object half-aperture angle of the objective lens. Increasing the object half-aperture angle of the objective lens and the refractive index of the object medium can both increase the numerical aperture, and thus increase the refractive index.

[0004] Currently, there are very few commercial microscopes that have both high field of view and numerical aperture and flat apochromatic aberration. The product of object-side field of view (mm) and numerical aperture is usually less than 0.75, which cannot meet practical needs. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an immersion objective, an optical system and a detection method to achieve a large field of view and a large numerical aperture, and to obtain a high-quality immersion objective and optical system.

[0006] This application provides an immersion objective lens, which, in the direction from the object side to the image side, sequentially includes: a first lens group with positive optical power, at least one set of negative optical power lens groups, and an immersion medium located on the object side of the first lens group and immersing at least a portion of the first lens group. The working distance S0 of the immersion medium located between the first lens group and the object side is equal to the focal length F of the immersion objective lens. obj The following conditions must be met:

[0007] 0 < S0 / F obj ≤0.16.

[0008] Optionally, the at least one group of negative optical power lenses sequentially includes, from the object side to the image side: a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. It should be understood that those skilled in the art can reduce or increase the number of lenses or lens groups by adjusting the lens surface shape and the relative positions between the lenses. Adjustments made based on the inventive concept of this application without inventive effort should also fall within the scope of protection of this application.

[0009] Optionally, the immersion medium includes a medium having a first refractive index n. 00 The first medium, and having a second refractive index n 01 The second medium, wherein the first medium is located between the second medium and the first lens group and has a thickness of d1, and the thickness of the second medium is d2, wherein S0 = d1 + d2, and the immersion objective further satisfies the following condition:

[0010] 0 < (n 00 d1+n 01 d2) / F obj ≤0.20.

[0011] Optional, n 01 >n 00 .

[0012] Optionally, the first medium is a liquid and the second medium is a solid.

[0013] Optionally, the first medium is water and the second medium is a glass slide.

[0014] Optionally, the first lens group, the second lens group, the fourth lens group, and the sixth lens group are cemented doublet lens groups, and the fifth lens group includes a cemented doublet lens group; the second lens group and the fourth lens group are symmetrically arranged about the third lens group.

[0015] Optionally, the first lens group includes a first lens and a second lens cemented together sequentially from the object side to the image side. The object side of the first lens is flat and the image side is convex. The image side of the second lens is convex. The ratio of the focal length of the first lens group to the focal length of the immersion objective lens is in the range of [3.39, 4.4].

[0016] Optionally, the third lens is a meniscus lens, and the ratio of the radius of curvature of the image-side surface of the third lens to the first distance is in the range of (-0.8, 1.0], where the first distance is the axial distance between the image-side surface of the third lens and the object surface; the ratio of the focal length of the third lens to the focal length of the immersion objective is in the range of (-6.6, 7.27).

[0017] Optionally, the second lens group includes a fourth lens and a fifth lens cemented together sequentially from the object side to the image side, wherein the absolute value of the difference between the refractive index of the fourth lens and the refractive index of the fifth lens is greater than 0.2.

[0018] Optionally, the third lens group is a cemented triplet lens, which includes a sixth lens, a seventh lens, and an eighth lens cemented together sequentially from the object side to the image side.

[0019] Optionally, the fourth lens group includes a ninth lens and a tenth lens cemented together sequentially from the object side to the image side, and the ratio of the focal length of the fourth lens group to the focal length of the immersion objective is less than 21.10.

[0020] Optionally, the immersion objective may also include an aperture stop.

[0021] Optionally, the sixth lens group includes a fourteenth lens and a fifteenth lens cemented together sequentially from the object side to the image side, and the ratio of the focal length of the sixth lens group to the focal length of the immersion objective lens ranges from -21.51 to -17.4.

[0022] Optionally, the fifth lens group includes an eleventh lens and a twelfth lens cemented together sequentially from the object side to the image side, and the fifth lens also includes a thirteenth lens, which is located between the twelfth lens and the sixth lens group.

[0023] This application also provides an optical system, including the aforementioned immersion objective and an imaging device located on the image side of the immersion objective and cooperating with the immersion objective.

[0024] Optionally, the optical system may further include a tube lens located between the immersion objective and the imaging device.

[0025] Optionally, the optical system further includes a light source for exciting the sample under test to generate a laser beam, the immersion objective for guiding the light generated by the light source to the sample under test and transmitting the laser beam, and the imaging device includes a time-delay integration camera for recording the laser beam and imaging the sample under test.

[0026] Optionally, the optical system further includes a light source shaping system located between the light source and the immersion objective, the light source shaping system being used to shape the light beam generated by the light source.

[0027] Optionally, the optical system further includes a compensating mirror, which is removably disposed in the optical path between the immersion objective and the imaging device.

[0028] This application also provides a detection method, including:

[0029] The optical system is used to detect the sample to be tested.

[0030] Optionally, the sample to be tested includes at least two sample detection surfaces spaced apart along the optical axis of the immersion objective lens. Detection of the sample to be tested using the optical system includes:

[0031] The immersion depth of the immersion objective lens in the immersion medium is adjusted to detect different surfaces of the sample.

[0032] This application embodiment also provides a nucleic acid detection system, including a sequencing chip and an optical system. The sequencing chip is used to support the sample to be detected. The optical system includes an objective lens and an immersion medium disposed between the objective lens and the sample to be detected. The end of the objective lens near the sample to be detected is immersed in the immersion medium. The working distance S0 between the objective lens and the sample to be detected by the immersion medium is equal to the focal length F of the objective lens. obj The following conditions must be met:

[0033] 0 < S0 / F obj ≤0.16.

[0034] Optionally, the objective lens comprises, in sequence from the object side to the image side, a first lens group having positive optical power and at least one lens group having negative optical power, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group.

[0035] Optionally, the at least one group of negative optical power lenses sequentially includes, from the object side to the image side: a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. It should be understood that those skilled in the art can reduce or increase the number of lenses or lens groups by adjusting the lens surface shape and the relative positions between the lenses. Adjustments made based on the inventive concept of this application without inventive effort should also fall within the scope of protection of this application.

[0036] Optionally, the optical system further includes an imaging device on the image side of the objective lens and cooperating with the objective lens, and a tube lens located between the objective lens and the imaging device.

[0037] Optionally, the immersion medium includes a glass slide covering the sample to be tested and an immersion liquid disposed on the side of the glass slide opposite to the sample to be tested, wherein the refractive index of the immersion liquid is n. 00 The refractive index of the glass slide is n 01 The working distance of the immersion liquid in the optical path of the objective lens is d1, and the thickness of the slide is d2, where S0 = d1 + d2. The immersion objective lens further satisfies the following condition:

[0038] 0 < (n 00 d1+n 01 d2) / F obj ≤0.20.

[0039] Optionally, the immersion liquid is water.

[0040] Optionally, the sequencing chip includes a slide spaced apart from the glass slide, and the sample to be detected includes a first detection sample fixed on the slide and a second detection sample opposite to the first detection sample and spaced apart from it and fixed on the glass slide.

[0041] This application embodiment also provides a biochemical testing method, including: loading a sample to be tested into a channel of a chip flow cell; and loading a reagent having multiple different reactive components into the channel of the chip flow cell to perform a biochemical reaction between the sample to be tested and the reagent;

[0042] The reaction components include at least one of the sample generation components or sample analysis components;

[0043] Optionally, the biochemical reaction includes generating a sample in a channel of the chip flow cell, including allowing different sample-generating components to flow into the channel and controlling the reaction conditions of the channel to generate the sample; and

[0044] The biochemical reaction includes analyzing the sample in the channel, including allowing sample analytical components to flow into the channel, the sample analytical components reacting with the sample to provide a relevant detectable signal;

[0045] The biochemical testing method further includes: identifying the detectable signal using an optical system, the optical system including an objective lens and an immersion medium disposed between the objective lens and the sample to be tested, wherein the working distance S0 of the immersion medium located between the first lens group and the objective lens is equal to the focal length F of the immersion objective lens. obj The following conditions must be met:

[0046] 0 < S0 / F obj ≤0.16.

[0047] Optionally, the objective lens comprises, in sequence from the object side to the image side: a first lens group with positive optical power, a third lens with positive optical power, and at least one group of negative optical power lenses, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group.

[0048] Optionally, the immersion objective comprises, in sequence from the object side to the image side: a first lens group, a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power.

[0049] It should be understood that those skilled in the art can reduce or increase the number of lenses or lens groups by adjusting the lens surface shape and the relative position between lenses. Adjustments based on the inventive concept of this application should also fall within the scope of protection of this application without creative effort.

[0050] Optionally, the biochemical reaction is a nucleic acid sequencing reaction, and the sample to be tested is a nucleic acid sequencing library.

[0051] Optionally, the detectable signal is an optical signal.

[0052] Optionally, the sample to be tested is a tissue sample, and the biochemical reaction is a specific binding reaction.

[0053] This application provides an immersion objective, an optical system, and a detection method. The immersion objective sequentially includes a first lens group with positive optical power, at least one lens group with negative optical power, and an immersion medium located on the object side of the first lens group and immersing at least a portion of the first lens group. The working distance S0 of the immersion medium between the first lens group and the object side is equal to the focal length F of the immersion objective. obj The following condition must be met: 0 < S0 / F obj ≤0.16. By using multiple lens groups, the immersion objective has a small size and low mass within a relatively compact size range, while achieving a large field of view, high resolution and low distortion, thus improving the optical performance of the immersion objective. Attached Figure Description

[0054] 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figures 1A-1E This is a schematic diagram of the structure of an immersion objective lens provided in an embodiment of this application;

[0056] Figure 2 A root mean square curve of wavefront difference of an immersion objective in two wavebands is provided for an embodiment of this application.

[0057] Figure 3 A waveform diagram showing the variation of wavefront difference with focal plane provided in an embodiment of this application;

[0058] Figure 4 A schematic diagram illustrating the distortion characteristics of an immersion objective lens provided in an embodiment of this application;

[0059] Figure 5 Another immersion objective provided for embodiments of this application: root mean square curves of wavefront difference in two wavebands;

[0060] Figure 6 Another waveform diagram showing the variation of wavefront difference with focal plane provided in this application embodiment;

[0061] Figure 7 A schematic diagram illustrating the distortion characteristics of another immersion objective lens provided in an embodiment of this application;

[0062] Figure 8 Another example of an immersion objective provided in this application shows the root mean square curve of wavefront difference in two wavebands.

[0063] Figure 9 Another waveform diagram showing the variation of wavefront difference with focal plane provided in the embodiments of this application;

[0064] Figure 10 This is a schematic diagram of the operation of an immersion objective lens in an embodiment of this application;

[0065] Figure 11 The detection result of an immersion objective lens provided in the embodiments of this application;

[0066] Figure 12 A schematic diagram of an optical system provided in an embodiment of this application;

[0067] Figure 13 A root mean square curve of wavefront difference of an optical system provided in an embodiment of this application;

[0068] Figure 14 This is a schematic diagram of another optical system provided in an embodiment of this application. Detailed Implementation

[0069] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0070] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0071] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0072] Currently, commercial microscopes rarely have both high field of view and high numerical aperture. The product of object-side field of view (mm) and numerical aperture is usually less than 0.75, which cannot meet practical needs and restricts the development of related fields.

[0073] For example, a sequencer is an instrument that can determine the base sequence, type, and quantification of DNA fragments. It is mainly used in human genome sequencing, gene diagnosis of human genetic diseases, infectious diseases and cancer, forensic paternity testing and individual identification, screening of bioengineering drugs, and hybridization breeding of plants and animals. The pursuit of high throughput, high speed, and low cost is the development direction of the next generation of sequencers, and these development directions all require sequencers to have both large numerical aperture and large field of view.

[0074] The resolution of a sequencer determines the information density that the sequencer can process per unit time. High resolution can bring high throughput and high speed, so the sequencer needs to have a large numerical aperture. After the object half aperture angle reaches its limit, increasing the refractive index of the object medium becomes a way to improve resolution.

[0075] Sequencing costs are mainly divided into three parts: instrument depreciation costs, sequencing reagent costs, and sequencing chip costs. Sequencing reagent and sequencing chip costs account for the majority of the total cost. Therefore, being able to sequence more DNA nanospheres (DNB spots) on a sequencing chip of the same area, or producing more DNB spots on a sufficiently small sequencing chip (with less reagent loss), can effectively reduce sequencing costs. This, in turn, allows for the continuation of Moore's Law and drives explosive growth in the application of sequencing technology in industries such as human health, animals, plants, and microorganisms. Similarly, high sequencer resolution also helps reduce sequencing chip and reagent costs. Therefore, improving sequencer resolution is key to increasing throughput, speed, and reducing consumable costs.

[0076] Furthermore, current immersion objectives are typically used in high-magnification microscopes, offering large numerical apertures and high magnification, but with extremely small object-side fields of view. For example, an NA 1.0 immersion objective generally has an object-side field of view of less than 1 mm. However, during sequencing, given a fixed sequencing chip size, camera frame rate, and platform movement speed, a larger object-side field of view reduces the number of images or time required to capture the entire sequencing chip. Immersion objectives with such small object-side fields of view are unsuitable for sequencers, and most commercially available objectives are currently used for visual inspection, failing to achieve near-diffraction-limited sharpness across the entire imaging range.

[0077] Obtaining a microscopic imaging system that combines large numerical aperture and large field of view, especially an objective lens that combines both, is an important research area in this field.

[0078] Currently, the vast majority of commercial sequencers use air objectives in their optical systems. Due to limitations in optical design, assembly, and tolerances, the object-side half-aperture angle has an upper limit, generally not exceeding 0.9. Existing immersion objectives are excessively large in size, volume, and weight, posing challenges to platform and overall system design, as well as industrialization. Furthermore, the increasing flow rates required by sequencers necessitate thicker coverslips for biochips, effectively increasing the working distance and adding to design complexity. In addition, the fluorescence microscopy system of sequencers uses image sensors for imaging, requiring strict field curvature correction.

[0079] Based on this, embodiments of this application provide an immersion objective, an optical system, and a detection method. The immersion objective, in the direction from the object side to the image side, sequentially includes a first lens group with positive optical power, a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. An immersion medium is located on the object side of the first lens group and at least a portion of the first lens group is immersed in it. The working distance S0 of the immersion medium between the first lens group and the object side is equal to the focal length F of the immersion objective. obj The following condition must be met: 0 < S0 / F obj ≤0.16. By using multiple lens groups, the immersion objective has a small size and low mass within a relatively compact size range, while achieving a large field of view, high resolution and low distortion, thus improving the optical performance of the immersion objective.

[0080] To better understand the technical solution and effects of this application, the specific embodiments will be described in detail below with reference to the accompanying drawings.

[0081] like Figure 1A-1D As shown, this application provides an immersion objective lens, including a first lens group G1 and other lens groups Gx located on the image side of the first lens group G1 along the optical axis. An immersion medium m is provided between the lens group G1 and the object side S, and the end of the lens group G1 near the object side is immersed in the immersion medium m. The number of other lens groups Gx is not limited, for example, it can be as follows: Figure 1C-1D Three groups, four groups, etc. The lens group Gx can be a single-piece lens (such as...). Figure 1B Gx1 in the image can also be a combination lens formed by multiple lenses (such as...). Figure 1B (GXn) etc. By adjusting the immersion depth of the first lens group G1 in the immersion medium m, the optical signal of the object S can be acquired. The depth of the immersion medium between the first lens group G1 and the object S is the working distance S0 of the immersion objective lens, and the focal length F of the objective lens. obj The following conditions must be met:

[0082] 0 < S0 / F obj ≤0.16.

[0083] The working distance S0 of the immersion objective can be changed by adjusting the immersion depth of the immersion objective in the immersion medium m, thereby achieving the above conditions and obtaining better image quality.

[0084] Specifically, refer to Figure 1EThe diagram shown is a structural schematic of an immersion objective lens provided in an embodiment of this application. In the direction from the object to the image, the immersion objective lens provided in this embodiment sequentially includes: a first lens group G1, a third lens L3, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, and a sixth lens group G6. The first lens group G1, the third lens L3, the second lens group G2, the third lens group G3, and the fourth lens group G4 all have positive optical power, while the fifth lens group G5 and the sixth lens group G6 have negative optical power.

[0085] The immersion objective may further include an immersion medium located on the object side of the first lens group and immersing at least a portion of the first lens group. The working distance S0 of the immersion medium (also referred to as the immersion working medium) located between the first lens group and the object side is related to the focal length F of the immersion objective. obj The following conditions must be met:

[0086] 0 < S0 / F obj ≤0.16.

[0087] Specifically, the immersion medium may include a first medium and a second medium, wherein the first medium has a first refractive index n. 00 The second medium has a second refractive index n 01 The first medium is located between the second medium and the first lens group and has a preset medium thickness, denoted as d1. The thickness of the second medium is d2. The working distance of the immersion medium is S0 = d1 + d2. The immersion objective lens satisfies the following conditions:

[0088] 0 < (n 00 d1+n 01 d2) / F obj ≤0.20.

[0089] In practical implementation, n 01 >n 00 The first medium can be a liquid, and the second medium can be a solid. When the first medium is a liquid, it can also be called an immersion liquid. The first medium can be water or other liquid media, and the second medium can be a glass slide. When the glass slide is placed on the sample to be tested, it can be called a coverslip.

[0090] The object side of the immersion objective lens can contain a sample solution. Specifically, the object side of the first lens group G0 sequentially includes a first medium, a second medium, and a sample solution. The first medium is water, the second medium is a coverslip, and the sample solution contains the sample to be tested. Alternatively, the first medium can also contain the sample to be tested. The plane containing the sample to be tested is the object plane. A slide can be placed on the side of the sample solution facing away from the second medium. The sample to be tested can be a biochemical chip or other detection samples. The refractive index of the first medium is close to that of the sample solution, typically between 1.3 and 1.36. The thickness of the coverslip is denoted as d2, and the focal length of the immersion objective lens is denoted as f. obj Then 0.06 <d2 / F obj <0.07. Object-side numerical aperture NA ≤ 1.0. Object-side half-field height is denoted as Ho, then Ho / f obj A value ≤0.0625 is suitable for microscope objectives ranging from 10x to 100x. For example, with a focal length of 10mm, the maximum image-side half-field height (maximum object-side field of view multiplied by the microscope system magnification) can reach 62.5mm. It should be understood that the immersion medium is also only a liquid medium. In this case, the sample solution of the analyte in the object side is in direct contact with the immersion medium; that is, the sample to be tested has an open structure containing the sample solution. Therefore, the immersion medium is preferably insoluble in the sample solution and has a lower density than the sample solution.

[0091] The first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group may include a cemented lens group composed of multiple lenses. For example, the first lens group, the second lens group, the fourth lens group, and the sixth lens group are cemented doublet lens groups, the third lens group is a cemented doublet or a cemented triplet lens, and the fifth lens group includes a cemented doublet lens group; the second lens group and the fourth lens group are symmetrically arranged about the third lens group.

[0092] In this embodiment, the first lens group G1 includes a first lens L1 and a second lens L2 cemented together sequentially from the object side to the image side. The first lens L1 faces the object side relative to the second lens L2. The object-side surface of the first lens L1 is denoted as S1, the image-side surface of the first lens L1 is cemented with the object-side surface of the second lens L2 and is denoted as the cemented surface S2, and the image-side surface of the second lens L2 is denoted as S3. The ratio of the focal length of the first lens group to the focal length of the immersion objective lens is in the range of [3.39, 4.4], that is, the first lens group G1 satisfies the following condition: 3.39 ≤ f1 / F obj ≤4.4, where f1 is the focal length of the first lens group G1, F obj The focal length of the immersed objective lens.

[0093] The refractive index of the first lens L1, n1 < 1.5, can be close to that of water to minimize spherical aberration. For example, the material of the first lens L1 can be fused silica, which has a refractive index close to that of water and good corrosion resistance. The first lens L1 can be a plano-convex lens, where the object-side surface S1 can be flat, and the image-side surface (i.e., the cemented surface S2) is convex. Compared to the first lens L1, the refractive index of the second lens L2 can be larger, for example, n2 > 1.8, to balance field curvature and reduce chromatic aberration. The image-side surface of the second lens L2 is convex.

[0094] In this embodiment, the third lens L3 can be a meniscus lens with a large positive optical power, sharing the positive optical power with the first lens group G1. The object-side surface of the third lens L3 can be denoted as S4, and the image-side surface as S5. The ratio of the focal length of the third lens to the focal length of the immersion objective lens ranges from -6.6 to 7.27, therefore the third lens L3 satisfies the following condition: -0.8 <R5 / d5≤1.0,6.6<f 31 / F obj ≤7.27, where f 31 It is the focal length of the second lens L3, F obj R5 is the focal length of the immersion objective, S5 is the radius of curvature of S5, and d5 is the first distance, which is the axial distance between the image-side surface S5 of the third lens and the object surface.

[0095] In this embodiment, the second lens group G2, in addition to further providing positive optical power, also has the function of correcting chromatic aberration. The second lens group G2 includes a fourth lens L4 and a fifth lens L5 cemented together sequentially from the object side to the image side. The fourth lens L4 and the fifth lens L5 can be cemented together. The object-side surface of the fourth lens L4 is denoted as S6, and the cemented surface of the fourth lens L4 and the object-side surface of the fifth lens L5 is denoted as the cemented surface S7. The image-side surface of the fifth lens L5 is denoted as S8. The absolute value of the difference between the refractive indices n4 of the fourth lens L4 and n5 of the fifth lens L5 is greater than 0.2, i.e., |n4-n5|>0.2. The focal length of the second lens group G2 is denoted as f2.

[0096] In this embodiment, the third lens group G3 is used to correct spherical aberration, coma, and chromatic aberration. The third lens group G3 includes at least two lenses cemented together sequentially from the object side to the image side. For example, the third lens group G3 includes a sixteenth lens and a seventeenth lens cemented together sequentially from the object side to the image side; or, the third lens group G3 may include a sixth lens L6, a seventh lens L7, and an eighth lens L8 cemented together sequentially from the object side to the image side. The object-side surface of the sixth lens L6 is denoted as S9; the image-side surface of the sixth lens L6 and the object-side surface of the seventh lens L7 are cemented together, denoted as cemented surface S10; the image-side surface of the seventh lens L7 and the object-side surface of the eighth lens L8 are cemented together, denoted as cemented surface S11; and the image-side surface of the eighth lens L8 is denoted as S12. The ratio of the focal length of the third lens group to the focal length of the immersion objective lens ranges from [-8.54, 20.98], meaning the third lens group G3 satisfies the following condition: -8.54 ≤ f 32 / f obj ≤20.98, where f 32 f is the focal length of the third lens group G3. obj The focal length of the immersed objective lens.

[0097] In this embodiment, the fourth lens group G4 and the second lens group G2 are symmetrically arranged about the third lens group G3. The fourth lens group G4 includes a ninth lens L9 and a tenth lens L10 cemented together sequentially from the object side to the image side. The object side of the ninth lens L9 is denoted as S13, and the image side of the ninth lens L9 is cemented together with the object side of the tenth lens L10, denoted as the cemented surface S14. The image side of the tenth lens L10 is denoted as S15. The ratio of the focal length of the fourth lens group to the focal length of the immersion objective is less than 21.10, that is, the fourth lens group G4 satisfies f4 / f obj <21.10, where f4 is the focal length of G4, f obj The focal length of the immersed objective lens.

[0098] In this embodiment, the fifth lens group G5 is used to compensate for astigmatism and field curvature, and also bears negative optical power. The fifth lens group G5 includes an eleventh lens L11 and a twelfth lens L12 cemented together sequentially from the object side to the image side. The object side surface of the eleventh lens L11 is denoted as S16. The image side surface of the eleventh lens L11 and the object side surface of the twelfth lens L12 are cemented together and denoted as the cemented surface S17. The image side surface of the twelfth lens L12 is denoted as S18. The focal length of the fifth lens group is denoted as f5.

[0099] The immersion objective also includes an aperture stop, for example, an aperture stop is provided between the fourth lens group G4 and the fifth lens group G5, that is, an aperture stop can be provided between the eleventh lens L11 and the tenth lens L10. Of course, the aperture stop can also be provided in other positions.

[0100] The fifth lens group G5 also includes a thirteenth lens L13, which is located on the image side of the twelfth lens L12. The thirteenth lens L13 can have negative optical power, for example, it can be a plano-concave lens. The object side of the thirteenth lens L13 is denoted as S19, and the image side of the thirteenth lens L13 is denoted as S20.

[0101] In this embodiment, the sixth lens group G6, in conjunction with the fifth lens group G5, is used to control field curvature and distortion. The sixth lens group G6 includes a fourteenth lens L14 and a fifteenth lens L15 cemented together sequentially from the object side to the image side. The sixth lens group G6 can be a meniscus cemented doublet. The object-side surface of the fourteenth lens L14 is denoted as S21. The image-side surface of the fourteenth lens L14 and the object-side surface of the fifteenth lens L15 are cemented together and denoted as the cemented surface S22. The image-side surface of the fifteenth lens L15 is denoted as S23. The ratio of the focal length of the sixth lens group to the focal length of the immersion objective lens ranges from -21.51 to -17.4, meaning the sixth lens group G6 satisfies -21.51. <f6 / f obj ≤-17.4, where f6 is the focal length of the sixth lens group G6, where f obj Let R be the focal length of the immersion objective. The radius of curvature R of S21 is... 21 Satisfy condition | R 21 / f obj |<1.2. The combined focal length f7 of the fifth lens group G5 and the fourteenth lens L14 should satisfy: -6≤f7 / f obj <-3.83, fobj is the focal length of the immersion objective.

[0102] As an example, the lenses are arranged sequentially from infinity to the object side, and F is taken as... obj =10mm. Details of one parameter for the immersion objective lens, optimized according to the implementation method, are shown in Table 1. The spacing represents the axial distance between this surface and the next surface along the optical axis. If the two surfaces belong to the same lens group, the spacing represents the center thickness of that lens. The aperture stop is on S13 and has a size of 33.5mm to achieve a numerical aperture of NA1.0. Specifically, f1 / F can be set. obj =3.39, R5 / d5 = 0.8, f 32 / F obj =7.27, f4 / f obj =8.54, f5 / f obj =-4.5, f6 / f obj = -21.07.

[0103] Table 1. Detailed parameters of one type of immersion objective.

[0104]

[0105]

[0106] The above immersion objectives can achieve flat-field imaging of different wavelengths across the entire field of view within a 1.25mm object-side field of view.

[0107] The diffraction-limited performance of an optical element means that wavefront aberrations are measured, and preferably the root mean square (rms) value of the wavefront aberrations of the total light flux is not greater than 0.07 times the tolerance wavelength. For each light with at least two different wavelengths (wavelength λ), the wavefront aberrations on the image surface do not exceed 0.07λrms in the predetermined numerical aperture of the immersion image.

[0108] refer to Figure 2 The image shows the root mean square (RMS) wavefront difference curves of an immersion objective lens in two wavelength ranges according to an embodiment of this application. The horizontal axis represents the object-side field of view, and the vertical axis represents the root mean square (RMS) wavefront difference of the immersion objective lens. Different colors represent different wavelengths. Figure 2 A represents the root mean square wavefront difference of the entire field of view in the red light band (0.663um~0.72um). The root mean square wavefront difference of red light with wavelengths of 0.663um, 0.672um and 0.72um in the object-side field of view is less than the diffraction limit (i.e., 0.07). The Poly curve represents the overall image quality, that is, the red light formed by the combination of all wavelengths in the red light band. The root mean square wavefront difference of the overall wavefront difference in the object-side field of view is also less than the diffraction limit (i.e., 0.07). Figure 2 B represents the root mean square (RMS) wavefront difference across the entire field of view in the green light band (0.545µm–0.610µm). For green light with wavelengths of 0.545µm, 0.558µm, and 0.61µm, the RMS wavefront difference within the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality; that is, the combined RMS wavefront difference of green light formed by the combination of all wavelengths in the green light band within the object-side field of view is also less than the diffraction limit. As can be seen from the figure, the immersion objective achieves diffraction-limited imaging quality across the entire field of view for both channels of the sequencer or the corresponding required channels.

[0109] refer to Figure 3 The figure shown is a curve illustrating the wavefront error versus focal plane variation according to an embodiment of this application. The horizontal axis represents the distance from the optimal focal plane (Focus in Millimeters), and the vertical axis represents the root mean square (RMS) wavefront error in waves. Figure 3A is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the red light band (0.663µm~0.72µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, line 2 is the curve of the field of view versus focal plane at object height = 0.4mm, and line 3 is the curve of the field of view versus focal plane at object height = 0.625mm. The in-field curvature of the entire field of view is less than 0.2µm. Figure 3 B is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the green light band (0.545µm~0.610µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, line 2 is the curve of the field of view versus focal plane at object height = 0.4mm, and line 3 is the curve of the field of view versus focal plane at object height = 0.625mm. The in-field curvature of the entire field of view is less than 0.2µm.

[0110] refer to Figure 4 The diagram shown illustrates the distortion characteristics of an immersion objective lens according to an embodiment of this application. The horizontal axis represents the object-side half-field height (Percent), in mm, and the vertical axis represents the distortion (Distortion), in %. As can be seen from the diagram, the distortion is less than 0.7% across the entire field of view. This immersion objective lens achieves a parfocal distance of 115 mm and has a compact structure.

[0111] As another example, the lenses are arranged sequentially from infinity to the object side, and F is taken as... obj =8mm. Details of another parameter for the immersion objective, optimized according to the implementation method, are shown in Table 2. The spacing represents the axial distance between this surface and the next surface along the optical axis. If the two surfaces belong to the same lens group, the spacing represents the center thickness of that lens. The aperture stop is on S15, with a diameter greater than or equal to 26.12mm to achieve a numerical aperture greater than or equal to NA1.0. Specifically, f1 / F can be set. obj =4.42, R5 / d5 = 1, f 32 / F obj =6.6, f4 / f obj =10.88, f5 / f obj =-6.03, f6 / f obj = -21.51.

[0112] Table 2. Details of another parameter for immersion objectives.

[0113]

[0114]

[0115] The above immersion objective with NA=1.0 can achieve flat-field imaging of different bands across the entire field of view within a 1mm object-side field of view.

[0116] refer to Figure 5 The figure shows the root mean square (RMS) wavefront difference curves of another immersion objective provided in this application embodiment in two waveband ranges. The horizontal axis represents the object-side field of view, and the vertical axis represents the root mean square (RMS) wavefront difference of the immersion objective. Different colors represent different wavelengths. Figure 5 A represents the root mean square wavefront difference of the entire field of view in the red light band (0.663um~0.72um). The root mean square wavefront difference of red light with wavelengths of 0.663um, 0.672um and 0.72um in the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality, that is, the root mean square wavefront difference of the red light formed by the combination of all wavelengths in the red light band in the object-side field of view is also less than the diffraction limit. Figure 5 B represents the root mean square (RMS) wavefront difference across the entire field of view in the green light band (0.545µm–0.610µm). For green light with wavelengths of 0.545µm, 0.558µm, and 0.61µm, the RMS wavefront difference within the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality; that is, the combined RMS wavefront difference of green light formed by the combination of all wavelengths in the green light band within the object-side field of view is also less than the diffraction limit. As can be seen from the figure, the immersion objective achieves diffraction-limited imaging quality across the entire field of view for both channels of the sequencer or the corresponding required channels.

[0117] refer to Figure 6 The figure shown is another waveform of wavefront difference versus focal plane provided in an embodiment of this application. The horizontal axis represents the distance from the optimal focal plane, and the vertical axis represents the root mean square of the wavefront difference. Figure 6 A is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the red light band (0.663µm~0.72µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, green line 2 is the curve of the field of view with an object height of 0.32mm versus focal plane, and line 3 is the curve of the field of view with an object height of 0.5mm versus focal plane. The in-field curvature of the entire field of view is less than 0.2µm. Figure 6 B is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the green light band (0.545µm~0.610µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, line 2 is the curve of the field of view with an object height of 0.32mm versus focal plane, and line 3 is the curve of the field of view with an object height of 0.5mm versus focal plane. The in-field curvature of the entire field of view is less than 0.2µm.

[0118] refer to Figure 7The figure shows a schematic diagram of the distortion characteristics of another immersion objective lens provided in this application embodiment. The horizontal axis is the object half field of view height in mm, and the vertical axis is the distortion in %. As can be seen from the figure, the distortion is less than 0.85% in the entire field of view.

[0119] As another example, the lenses are arranged sequentially from infinity to the object side, and F is taken as... obj =5mm. Further details of another parameter for the immersion objective, optimized according to the implementation method, are shown in Table 3. The spacing represents the axial distance between this surface and the next surface along the optical axis. If the two surfaces belong to the same lens group, the spacing represents the center thickness of that lens. The aperture stop is on S15 with a diameter of 17.63mm to achieve a numerical aperture of NA1.0. Specifically, f1 / F can be set. obj =4.26, R5 / d5=0.93, R5 / d5=6.914, f4 / f obj =20.98, f5 / f obj = -3.834, f6 / f obj = -17.4.

[0120] Table 3. Details of another parameter for immersion objectives.

[0121]

[0122]

[0123]

[0124] The above immersion objective with NA=1.0 can achieve flat-field imaging of different bands across the entire field of view within a 1mm object-side field of view.

[0125] refer to Figure 8 The image shows the root mean square (RMS) wavefront difference curves of another immersion objective provided in this application across two wavebands. The horizontal axis represents the object-side field of view, and the vertical axis represents the root mean square (RMS) wavefront difference of the immersion objective. Different colors represent different wavelengths. Figure 8 A represents the root mean square wavefront difference of the entire field of view in the red light band (0.663um~0.72um). The root mean square wavefront difference of red light with wavelengths of 0.663um, 0.672um and 0.72um in the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality, that is, the root mean square wavefront difference of the red light formed by the combination of all wavelengths in the red light band in the object-side field of view is also less than the diffraction limit. Figure 8B represents the root mean square (RMS) wavefront difference across the entire field of view in the green light band (0.545µm–0.610µm). For green light with wavelengths of 0.545µm, 0.558µm, and 0.61µm, the RMS wavefront difference within the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality; that is, the combined RMS wavefront difference of green light formed by the combination of all wavelengths in the green light band within the object-side field of view is also less than the diffraction limit. As can be seen from the figure, the immersion objective achieves diffraction-limited imaging quality across the entire field of view for both channels of the sequencer or the corresponding required channels.

[0126] refer to Figure 9 The figure shown is another waveform of wavefront difference versus focal plane provided in an embodiment of this application. The horizontal axis represents the distance from the optimal focal plane, and the vertical axis represents the root mean square of the wavefront difference. Figure 9 A is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the red light band (0.663µm~0.72µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, line 2 is the curve of the field of view versus focal plane at object height = 0.2mm, and line 3 is the curve of the field of view versus focal plane at object height = 0.32mm. The in-field curvature of the entire field of view is less than 0.2µm. Figure 9 B is a graph showing the wavefront aberration versus focal plane curves for different fields of view in the green light band (0.545µm~0.610µm). As can be seen from the graph, different field of view positions have different wavefront aberration RMS. Line 1 in the graph is the curve of the on-axis object point wavefront aberration versus focal plane, line 2 is the curve of the field of view versus focal plane at object height = 0.2mm, and line 3 is the curve of the field of view versus focal plane at object height = 0.32mm. The in-field curvature of the entire field of view is less than 0.05µm.

[0127] The immersion objective provided in this application has a compact structure, comparable to the high-throughput microscope objectives from CG Corporation, but its length is shortened to about 1 / 4, and its weight is reduced by tens of times, significantly reducing its size and weight. Taking the focal length F of the immersion objective as an example... obj Taking a 10mm lens as an example, the parfocal distance of the immersion objective is <120mm, and the weight is <750g. Furthermore, the immersion objective has a reasonable design structure and tolerance allocation, reasonable tolerance sensitivity, is easy to manufacture, and has controllable costs, demonstrating good process feasibility. It has already been mass-produced according to the parameters in the aforementioned embodiments, and the finished product achieves diffraction-limited imaging quality across the entire field of view. In addition, this immersion objective is versatile and can be applied to any microscopy system, as well as any other imaging application requiring a large field of view and high resolution, such as front-end manufacturing and back-end testing equipment for semiconductors, nanotechnology, biological microscopy, and materials analysis. This immersion objective can be used in rapid detection systems such as sequencers, as well as other immersion display imaging systems with infinity distances of 10X-100X.

[0128] Therefore, in the embodiments of this application, a plan-field apochromatic immersion objective with a large field of view, high resolution, NA 1.0, low distortion, and suitable for thicker coverslips can be achieved within a relatively compact size range. This plan-field apochromatic optical design with a large field of view and large numerical aperture surpasses that of typical commercial objectives, resulting in excellent optical performance of the immersion objective-based optical system. For example, for sequencers, this can improve the resolution of the optical system, increase the throughput of the sequencer, and reduce sequencing costs.

[0129] When the sample to be tested comprises two or more layers, the cost of consumables can be effectively reduced. This means the sample to be tested includes at least two sample detection surfaces spaced apart along the optical axis of the immersion objective. For example, if the sample to be tested is a chip with biomolecules adsorbed on both its upper and lower surfaces, then the sample (chip to be tested) has a first detection surface and a second detection surface. Imaging the sample to be tested allows for the detection of multiple detection surfaces. However, multi-layered chips require the optical system to achieve clear imaging even within a micrometer-wide focusing distance. This is impossible for optical systems based on large-NA air objectives without compensation elements. In other words, when patterns are present on both the upper and lower surfaces of the sample solution, an additional compensation lens needs to be added to the air objective to compensate for the spherical aberration caused by the sample solution layer. This increases instability to the reliability of the objective and prevents complete image quality compensation to the ideal level.

[0130] However, the first medium immersed in the objective lens is also a liquid, with a refractive index and dispersion coefficient similar to or even identical to that of the sample solution. Therefore, changing the working distance of the immersion medium can compensate for the focal length difference between the upper and lower surfaces of the water layer in the chip sample solution. In other words, when the sample to be tested includes at least two sample detection surfaces spaced apart along the optical axis of the immersion objective lens (e.g., when both the upper and lower surfaces of the sample solution have patterns), the detection of different sample detection surfaces, i.e., the detection of patterns in different layers, can be achieved by adjusting the thickness of the first medium. Specifically, the sample to be tested includes a first detection surface and a second detection surface. The first detection surface and the coverslip have a first distance, and the second detection surface and the coverslip have a second distance. When detecting the first detection surface, the first medium between the first lens group and the coverslip has a first thickness; when detecting the second detection surface, the first medium between the first lens group and the coverslip has a second thickness.

[0131] refer to Figure 10 The diagram shown is a schematic representation of the operation of an immersion objective lens in an embodiment of this application. (Refer to...) Figure 10 As shown in Figure A, a pattern on the upper surface of a sample solution (serving as a first detection surface) can be detected using a first medium having a first thickness. When the sample solution is located between a slide and a coverslip, the pattern is provided by a second detection sample fixed to the lower surface of the slide. (Refer to...) Figure 10As shown in B, the pattern on the lower surface of the sample solution (as the second detection surface) is detected using a first medium of second thickness. When the sample solution is located between the slide and the coverslip, the pattern is provided by a first detection sample fixed on the upper surface of the slide.

[0132] Furthermore, when the sample to be tested includes multiple sample detection surfaces spaced apart along the optical axis of the immersion objective, meaning the sample solution has a pattern with more than two layers, a compensation mirror can be added to achieve the detection of even more layers of pattern, based on adjustments to the first medium. The compensation mirror is removably disposed in the optical path between the immersion objective and the imaging device. For example, when the sample to be tested is also present in the first medium, the sample may have a third detection surface located in the first medium on the coverslip. In this case, a compensation mirror can be added to detect the third detection surface. The compensation mirror is located in the optical path on the side of the sixth lens group furthest from the first lens group. (Reference) Figure 10 As shown in Figure C, when the first medium has a third thickness and a compensation mirror is provided, the pattern on the coverslip (as the third detection surface) is detected to improve detection efficiency and reduce detection costs.

[0133] Since the immersion objective lens in this embodiment can be directly focused for double-layer sample detection without the need for additional optical elements for aberration compensation, it can also solve the problem of compensating for the optical path difference between the upper and lower layers of the double-layer chip, thereby enabling the detection of double-layer samples. Therefore, the thickness of the sample solution does not need to have very strict tolerance requirements and can be compatible with chips with continuous different sample solution thicknesses. It is only necessary to keep the sum of the working distance WD and the sample solution thickness d constant, which simplifies the detection process.

[0134] The root mean square value of the wavefront difference of an immersion objective lens can be obtained by interferometer testing, as follows: Figure 11 The image shows the detection result of an immersion objective lens provided in an embodiment of this application, where 11A represents the interference pattern detected by the interferometer, and 11B is the root mean square value of the wavefront difference. The result shows that the wavefront difference RMS is 0.0524, which meets the design value.

[0135] This application provides an immersion objective lens, which, in a direction from the object side to the image side, sequentially includes a first lens group with positive optical power, a third lens group with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. An immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group. The working distance S0 of the immersion medium between the first lens group and the object side is equal to the focal length F of the immersion objective lens. obj The following condition must be met: 0 < S0 / F obj≤0.16. By using multiple lens groups, the immersion objective has a small size and low mass within a relatively compact size range, while achieving a large field of view, high resolution and low distortion, thus improving the optical performance of the immersion objective.

[0136] Based on the immersion objective lens provided in this application embodiment, this application embodiment also provides an optical system, the optical system including the aforementioned immersion objective lens, and an imaging device located on the image side of the immersion objective lens and cooperating with the immersion objective lens. The imaging device is used to acquire an image of the sample to be tested.

[0137] refer to Figure 12 The diagram shown is a schematic of an optical system provided in an embodiment of this application. The optical system also includes a tube lens located between the immersion objective and the imaging device. The immersion objective and the tube lens are used in conjunction, and the immersion objective is located to the left of the tube lens in the diagram. Different focal length tube lenses paired with the immersion objective result in different magnifications of the high-resolution optical system. That is, the optical modules obtained by scaling the immersion objective, the tube lens, and the illumination system separately, or the overall optical system obtained by scaling, are all within the scope of protection of this patent. For example, using the immersion objective in the first example described above, paired with a tube lens with a focal length of 200mm, a 20X microscopic optical system can be obtained.

[0138] Specifically, the tube lens can include a structure with two sets of cemented doublet lenses to further compensate for the transverse chromatic aberration and other residual higher-order aberrations of the immersion objective. The immersion objective and the tube lens are parallel to each other to facilitate the insertion of various filters and dichroic mirrors. The resulting optical system achieves a wave phase aberration of <0.05λ across the entire 25mm frame.

[0139] refer to Figure 13 The image shown is a root mean square (RMS) waveform of the wavefront difference of an optical system provided in an embodiment of this application. The horizontal axis represents the object-side field of view, and the vertical axis represents the RMS wavefront difference of the optical system. Different colors represent light of different wavelengths. Figure 13 A represents the root mean square (RMS) wavefront difference of the red light channel. The RMS wavefront differences of red light with wavelengths of 0.663 μm, 0.672 μm, and 0.72 μm are all less than the diffraction limit in the object-side field of view. The Poly curve represents the overall image quality, that is, the overall RMS wavefront difference of red light formed by the combination of all wavelengths in the red light band is also less than the diffraction limit in the object-side field of view. Figure 13B represents the root mean square (RMS) wavefront difference of the green light channel. For green light with wavelengths of 0.545 μm, 0.558 μm, and 0.61 μm, the RMS wavefront difference within the object-side field of view is less than the diffraction limit. The Poly curve represents the overall image quality; that is, the combined RMS wavefront difference of the green light formed by the combination of all wavelengths in the green light band within the object-side field of view is also less than the diffraction limit. As can be seen from the figure, the optical system achieves diffraction-limited imaging quality across the entire wavelength range required by the sequencer throughout the entire field of view.

[0140] refer to Figure 14 The diagram shown illustrates another optical system provided in this application embodiment. The optical system may further include a light source for exciting the sample to generate laser light, an immersion objective for guiding the light generated by the light source to the sample and transmitting the laser light, i.e., the light source provides real-time illumination to the sample under test, and the immersion objective magnifies the illuminated area of ​​the sample under test. The illumination method can be critical illumination or carat illumination; it can achieve illumination shaping for array imaging, as well as illumination shaping for linear array or TDI linear array imaging. The imaging device may further include a camera for recording the laser light and imaging the sample under test.

[0141] The camera can be a time-delay integration (TDI) camera or other area array cameras. When the camera in the optical system is a time-delay integration camera, the optical system may also include a light source shaping system located between the light source and the immersion objective lens, for shaping the light beam generated by the light source to achieve linear focusing and shaping of the light emitted by the light source. The light source shaping system may include two orthogonal cylindrical lenses.

[0142] In this embodiment, the light source may include a laser fiber, and the optical system may further include a dichroic mirror for reflecting the light beam generated by the light source to the sixth lens group and transmitting the light beam emitted from the sixth lens group. That is, the dichroic mirror can reflect the light emitted by the light source towards the immersion objective and transmit the light reflected from the sample under test and emitted through the immersion objective, allowing it to pass through the tube lens to the camera. A reflector may also be provided between the dichroic mirror and the tube lens to change the direction of the light beam.

[0143] When the camera is a TDI camera, the aspect ratio of the field of view is determined by the camera's pixel size, integration level, and sensor width: x / y = L / D, where x is the object-side field of view width, y is the object-side field of view linewidth, L is the number of pixels in the longitudinal direction of the TDI camera's sensor, and D is the integration level. The object-side field of view linewidth can be calculated as y = p * D / M, where p is the pixel size and M is the magnification of the imaging system.

[0144] In this embodiment, the optical system may further include a compensating mirror, which is removably disposed in the optical path between the immersion objective and the imaging device.

[0145] Based on the optical system provided in the embodiments of this application, the embodiments of this application also provide a detection method, including:

[0146] The optical system is used to detect the sample to be tested.

[0147] Optionally, the sample to be tested includes at least two sample detection surfaces spaced apart along the optical axis of the immersion objective lens. Detection of the sample to be tested using the optical system includes:

[0148] The immersion depth of the immersion objective lens in the first medium is adjusted to detect different sample detection surfaces.

[0149] This application also provides a nucleic acid detection system, including a sequencing chip and the aforementioned optical system, wherein the sequencing chip is used to support the detection sample.

[0150] Specifically, the optical system includes an objective lens and an immersion medium disposed between the objective lens and the sample to be tested. The end of the objective lens closest to the sample to be tested is immersed in the immersion medium. The working distance S0 of the immersion medium between the objective lens and the sample to be tested is equal to the focal length F of the objective lens. obj The following conditions must be met:

[0151] 0 < S0 / F obj ≤0.16.

[0152] The objective lens comprises, in sequence from the object side to the image side: a first lens group with positive optical power and at least one lens group with negative optical power, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group.

[0153] The at least one group of negative optical power lenses sequentially includes, from the object side to the image side: a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power.

[0154] Optionally, the optical system further includes an imaging device on the image side of the objective lens and cooperating with the objective lens, and a tube lens located between the objective lens and the imaging device.

[0155] Optionally, the immersion medium includes a glass slide covering the sample to be tested and an immersion liquid disposed on the side of the glass slide opposite to the sample to be tested, wherein the refractive index of the immersion liquid is n. 00 The refractive index of the glass slide is n 01The working distance of the immersion liquid in the optical path of the objective lens is d1, and the thickness of the slide is d2, where S0 = d1 + d2. The immersion objective lens further satisfies the following condition:

[0156] 0 < (n 00 d1+n 01 d2) / F obj ≤0.20.

[0157] Optionally, the immersion liquid is water.

[0158] Optionally, the sequencing chip includes a slide spaced apart from the glass slide, and the sample to be detected includes a first detection sample fixed on the slide and a second detection sample opposite to the first detection sample and spaced apart from it and fixed on the glass slide.

[0159] This application also provides a biochemical testing method using the above-described optical system, comprising: loading a sample to be tested into a channel of a chip flow cell; loading reagents having multiple different reactive components into the channel of the chip flow cell to perform a biochemical reaction between the sample to be tested and the reagents; and using the above-described optical system to detect the relevant detectable signals generated by the biochemical reaction.

[0160] The reaction components include at least one of the sample generation components or sample analysis components;

[0161] Optionally, the biochemical reaction includes generating a sample in a channel of the chip flow cell, including allowing different sample generating components to flow into the channel and controlling the reaction conditions of the channel to generate the sample; and the biochemical reaction includes analyzing the sample in the channel, including allowing sample analytical components to flow into the channel, the sample analytical components reacting with the sample to provide a relevant detectable signal.

[0162] The biochemical testing method further includes: identifying the detectable signal using the aforementioned optical system, wherein the optical system includes an objective lens and an immersion medium disposed between the objective lens and the sample to be tested, and the working distance S0 of the immersion medium located between the first lens group and the objective lens is equal to the focal length F of the objective lens. obj The following conditions must be met:

[0163] 0 < S0 / F obj ≤0.16.

[0164] Optionally, the objective lens comprises, in sequence from the object side to the image side: a first lens group with positive optical power, a third lens with positive optical power, and at least one group of negative optical power lenses, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group.

[0165] Optionally, the objective lens comprises, in sequence from the object side to the image side: a first lens group, a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power.

[0166] Optionally, the biochemical reaction is a nucleic acid sequencing reaction, and the sample to be tested is a nucleic acid sequencing library.

[0167] Optionally, the detectable signal is an optical signal. In other embodiments, the detectable signal may also include signals other than optical signals, in which case the detection of the detectable signal can be performed by a system other than the optical system.

[0168] Optionally, the sample to be tested is a tissue sample, and the biochemical reaction is a specific binding reaction.

[0169] When using the aforementioned optical system to examine relevant detectable signals, the imaging quality can be adjusted by regulating the immersion depth of the objective lens in the immersion medium. Preferably, the biochemical reaction is a nucleic acid sequencing reaction, and the sample to be tested is a nucleic acid sequencing library. The aforementioned chip flow cell can have, for example, the structure of a multilayer sample to be tested described above. By changing the immersion depth of the objective lens in the immersion medium, detection of nucleic acid sequencing libraries on different detection surfaces can be achieved. The detectable signal is preferably an optical signal. Furthermore, the sample to be tested can also be a tissue sample, and the biochemical reaction is a specific binding reaction.

[0170] When describing elements of various embodiments of this application, the articles “a,” “an,” “this,” and “described” are all intended to indicate that there are one or more elements. The words “comprising,” “including,” and “having” are inclusive and mean that there may be other elements in addition to those listed.

[0171] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments. For example, the embodiments of detection methods, nucleic acid detection systems, biochemical detection methods, etc. can be referred to the description of the immersion lens embodiments.

[0172] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. An immersion objective lens, characterized in that, The immersion objective comprises, in sequence from the object side to the image side: a first lens group with positive optical power, at least one lens group with negative optical power, and an immersion medium located on the object side of the first lens group and immersing at least a portion of the first lens group. The working distance S0 of the immersion medium between the first lens group and the object side is equal to the focal length F of the immersion objective. obj The following conditions must be met: 0<S0 / F obj ≤0.16; The immersion medium includes a first refractive index n. 00 The first medium, and having a second refractive index n 01 The second medium, wherein the first medium is located between the second medium and the first lens group and has a thickness of d1, and the thickness of the second medium is d2, wherein S0 = d1 + d2, and the immersion objective further satisfies the following condition: 0<(n 00 d1+n 01 d2) / F obj ≤0.20; The at least one group of negative optical power lenses sequentially includes, from the object side to the image side: a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. The immersion objective lens has 7 lens groups with optical power.

2. The immersion objective lens according to claim 1, characterized in that, n 01 >n 00 。 3. The immersion objective lens according to claim 2, characterized in that, The first medium is a liquid, and the second medium is a solid.

4. The immersion objective lens according to claim 3, characterized in that, The first medium is water, and the second medium is a glass slide.

5. The immersion objective lens according to claim 1, characterized in that, The first lens group, the second lens group, the fourth lens group, and the sixth lens group are cemented doublet lens groups, and the fifth lens group includes a cemented doublet lens group; the second lens group and the fourth lens group are symmetrically arranged about the third lens group.

6. The immersion objective lens according to claim 5, characterized in that, The first lens group includes a first lens and a second lens cemented together sequentially from the object side to the image side. The object side of the first lens is flat and the image side is convex. The image side of the second lens is convex. The ratio of the focal length of the first lens group to the focal length of the immersion objective lens is in the range of [3.39, 4.4].

7. The immersion objective lens according to claim 5, characterized in that, The third lens is a meniscus lens, and the ratio of the radius of curvature of the image-side surface of the third lens to the first distance is in the range of (-0.8, 1.0], where the first distance is the axial distance between the image-side surface of the third lens and the object surface; the ratio of the focal length of the third lens to the focal length of the immersion objective is in the range of (-6.6, 7.27).

8. The immersion objective lens according to claim 5, characterized in that, The second lens group includes a fourth lens and a fifth lens cemented together sequentially from the object side to the image side, wherein the absolute value of the difference between the refractive index of the fourth lens and the refractive index of the fifth lens is greater than 0.

2.

9. The immersion objective lens according to claim 5, characterized in that, The third lens group is a cemented triplet lens, which includes a sixth lens, a seventh lens, and an eighth lens cemented together sequentially from the object side to the image side.

10. The immersion objective lens according to claim 5, characterized in that, The fourth lens group includes a ninth lens and a tenth lens cemented together sequentially from the object side to the image side, and the ratio of the focal length of the fourth lens group to the focal length of the immersion objective is less than 21.

10.

11. The immersion objective lens according to claim 5, characterized in that, The immersion objective also includes an aperture stop.

12. The immersion objective lens according to claim 5, characterized in that, The sixth lens group includes a fourteenth lens and a fifteenth lens cemented together sequentially from the object side to the image side, and the ratio of the focal length of the sixth lens group to the focal length of the immersion objective lens ranges from -21.51 to -17.

4.

13. The immersion objective lens according to claim 5, characterized in that, The fifth lens group includes an eleventh lens and a twelfth lens cemented together sequentially from the object side to the image side. The fifth lens also includes a thirteenth lens, which is located between the twelfth lens and the sixth lens group.

14. An optical system, characterized in that, It includes an immersion objective as described in any one of claims 1-13 and an imaging device located on the image side of the immersion objective and cooperating with the immersion objective.

15. The optical system according to claim 14, characterized in that, The optical system also includes a tube mirror located between the immersion objective and the imaging device.

16. The optical system according to claim 14 or 15, characterized in that, The optical system further includes a light source for exciting the sample under test to generate a laser beam, the immersion objective for guiding the light generated by the light source to the sample under test and transmitting the laser beam, and the imaging device includes a time-delay integration camera for recording the laser beam and imaging the sample under test.

17. The optical system according to claim 16, characterized in that, The optical system also includes a light source shaping system located between the light source and the immersion objective lens, the light source shaping system being used to shape the light beam generated by the light source.

18. The optical system according to claim 14 or 15, characterized in that, The optical system also includes a compensating mirror, which is removably disposed in the optical path between the immersion objective and the imaging device.

19. A detection method, characterized in that, include: The optical system described in any one of claims 14-18 is used to detect the sample to be tested.

20. The method according to claim 19, characterized in that, The sample to be tested includes at least two sample detection surfaces spaced apart along the optical axis of the immersion objective. The detection of the sample to be tested using the optical system includes: The immersion depth of the immersion objective lens in the immersion medium is adjusted to detect different surfaces of the sample.

21. A nucleic acid detection system, characterized in that, The system includes a sequencing chip and an optical system. The sequencing chip supports the sample to be tested. The optical system includes an objective lens and an immersion medium disposed between the objective lens and the sample to be tested. The end of the objective lens closest to the sample to be tested is immersed in the immersion medium. The working distance S0 between the objective lens and the sample to be tested and the focal length F of the objective lens are... obj The following conditions must be met: 0<S0 / F obj ≤0.16; The immersion medium includes a glass slide covering the sample to be tested and an immersion liquid disposed on the side of the glass slide opposite to the sample to be tested, wherein the refractive index of the immersion liquid is n. 00 The refractive index of the glass slide is n 01 The working distance of the immersion liquid in the optical path of the objective lens is d1, and the thickness of the slide is d2, where S0 = d1 + d2. The immersion objective lens further satisfies the following condition: 0<(n 00 d1+n 01 d2) / F obj ≤0.20; The objective lens comprises, in sequence from the object side to the image side: a first lens group with positive optical power and at least one lens group with negative optical power, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group; The at least one group of negative optical power lenses sequentially includes, from the object side to the image side: a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. The immersion objective lens has 7 lens groups with optical power.

22. The nucleic acid detection system according to claim 21, characterized in that, The optical system also includes an imaging device on the image side of the objective lens and cooperating with the objective lens, and a tube lens located between the objective lens and the imaging device.

23. The nucleic acid detection system according to claim 21, characterized in that, The immersion liquid is water.

24. The nucleic acid detection system according to claim 21, characterized in that, The sequencing chip includes a slide spaced apart from a glass slide, and the sample to be tested includes a first test sample fixed on the slide and a second test sample that is opposite to the first test sample, spaced apart from it, and fixed on the glass slide.

25. A biochemical testing method, characterized in that, include: The sample to be tested is loaded into the channel of the chip flow cell; And loading reagents with multiple different reactive components into the channels of the chip flow cell to perform a biochemical reaction between the sample to be tested and the reagents; The reaction components include at least one of the sample generation components or sample analysis components; Optionally, the biochemical reaction includes generating a sample in a channel of the chip flow cell, including allowing different sample-generating components to flow into the channel and controlling the reaction conditions of the channel to generate the sample; and The biochemical reaction includes analyzing the sample in the channel, including allowing sample analytical components to flow into the channel, the sample analytical components reacting with the sample to provide a relevant detectable signal; The biochemical testing method further includes: identifying the detectable signal using an optical system, the optical system comprising an objective lens and an immersion medium disposed between the objective lens and the sample to be tested, wherein the working distance S0 of the immersion medium between the objective lens and the sample to be tested is equal to the focal length F of the objective lens. obj The following conditions must be met: 0<S0 / F obj ≤0.16; The immersion medium includes a glass slide covering the sample to be tested and an immersion liquid disposed on the side of the glass slide opposite to the sample to be tested. The refractive index of the immersion liquid is n00, the refractive index of the glass slide is n01, the working distance of the immersion liquid in the optical path of the objective lens is d1, and the thickness of the glass slide is d2, where S0 = d1 + d2. The objective lens further satisfies the following condition: 0<(n00d1+n01d2) / Fobj≤0.20; The objective lens comprises, in sequence from the object side to the image side: a first lens group with positive optical power, a third lens with positive optical power, and at least one lens group with negative optical power, wherein the immersion medium is located on the object side of the first lens group and immerses at least a portion of the first lens group. The objective lens comprises, in sequence from the object side to the image side: a first lens group, a third lens with positive optical power, a second lens group with positive optical power, a third lens group with positive optical power, a fourth lens group with positive optical power, a fifth lens group with negative optical power, and a sixth lens group with negative optical power. The immersion objective lens has 7 lens groups with optical power.

26. The biochemical testing method according to claim 25, characterized in that, The biochemical reaction is a nucleic acid sequencing reaction, and the sample to be tested is a nucleic acid sequencing library.

27. The biochemical testing method according to claim 25, characterized in that, The detectable signal is an optical signal.

28. The biochemical testing method according to claim 26, characterized in that, The sample to be tested is a tissue sample, and the biochemical reaction is a specific binding reaction.

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