Microscope objective lens, microscope optical detection system, and sequencer

Abstract

The present application provides a microscope objective lens, comprising a first lens group, a second lens group, a third lens group, and a positive lens which are sequentially arranged from an object side to an image side along an optical axis of the microscope objective lens. The first lens group has a positive focal power, and comprises a first lens and a second lens that are sequentially arranged from the object side to the image side. The first lens and the second lens satisfy the expression: 2.26<=f2 / Fobj<=2.82, where f2 is a combined focal length of the first lens and the second lens, and Fobj is an effective focal length of the microscope objective lens. The second lens group has a positive focal power. The third lens group comprises at least one negative lens. The above-described microscope objective lens can accommodate both a large field of view and a large numerical aperture. The present application further provides a microscope optical detection system and a sequencer.

Description

Microscope objectives, microscopic optical inspection system and sequencer Technical Field

[0001] This application relates to the field of optical inspection technology, and in particular to a microscope objective, a microscopic optical inspection system including the microscope objective, and a sequencer including the microscope objective optical inspection system. Background Technology

[0002] Large-field apochromatic objectives with near-diffraction-limited imaging quality typically consist of a dozen or more lenses to balance the various aberrations introduced by the large field of view and large numerical aperture. Their complex structure, coupled with limitations in objective size and weight, makes optical design extremely challenging. 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, modification equipment, and highly experienced technical personnel.

[0003] Therefore, currently used objectives cannot simultaneously achieve a large field of view and a large numerical aperture; the product of the object-side field of view (mm) and the numerical aperture is usually less than 0.75. Summary of the Invention

[0004] This application provides a microscope objective comprising a first lens group, a second lens group, a third lens group, and a positive lens arranged sequentially from the object side to the image side along the optical axis of the microscope objective; the first lens group has positive optical power and includes a first lens and a second lens arranged sequentially from the object side to the image side, wherein the first lens and the second lens satisfy: 2.26 <= f2 / Fob j <= 2.82, where f2 is the combined focal length of the first lens and the second lens, Fob j The effective focal length of the microscope objective is given; the second lens group has positive optical power; the third lens group includes at least one negative lens.

[0005] A second aspect of this application provides a microscopic optical inspection system, comprising: the aforementioned microscope objective, a telescope, and an image sensor; the telescope is located between the microscope objective and the image sensor, the image sensor has a photosensitive surface, the telescope is used to focus a light beam from the microscope objective onto the photosensitive surface, and the image sensor is used to sense the light beam to form an image.

[0006] A third aspect of this application provides a sequencer, comprising: a sequencing chip and an optical system optically coupled to the sequencing chip; the sequencing chip is used to support a biological sample to be tested; the optical system includes a microscope objective, a light source, and an optical sensor; the light source is operably optically coupled to the sequencing chip to emit illumination light of a specified wavelength onto the biological sample to be tested, and the biological sample to be tested generates a detectable light signal in response to the illumination light; the optical sensor is coupled to the microscope objective and acquires the detectable light signal through the microscope objective; the microscope objective includes a first lens group, a second lens group, a third lens group, and a positive lens arranged sequentially from the object side to the image side along the optical axis of the microscope objective; the first lens group has positive optical power and includes a first lens and a second lens arranged sequentially from the object side to the image side, wherein the first lens and the second lens satisfy: 2.26 <= f2 / Fob j <= 2.82, where f2 is the combined focal length of the first lens and the second lens, Fob j The effective focal length of the microscope objective is given; the second lens group has positive optical power; the third lens group includes at least one negative lens.

[0007] The microscope objective, microscope optical detection system, and sequencer described in this application include a microscope objective comprising a first lens group, a second lens group, a third lens group, and a positive lens arranged sequentially from the object side to the image side along the optical axis of the microscope objective. The first lens group has positive optical power and includes a first lens and a second lens arranged sequentially from the object side to the image side. The first lens and the second lens satisfy 2.26 <= f2 / Fobj <= 2.82, where f2 is the combined focal length of the first lens and the second lens, and Fobj <= 2.82. j The effective focal length of the microscope objective is defined as follows: the second lens group has positive optical power; the third lens group includes at least one negative lens. Thus, the microscope objective can possess both a large field of view and a large numerical aperture, which is beneficial for improving the resolution of the microscope objective. When the microscope objective is applied to microscopic optical inspection systems and sequencers, it can effectively improve the throughput and speed of the microscopic optical inspection systems and sequencers, and help reduce the cost of the microscopic optical inspection systems and sequencers. Attached Figure Description

[0008] Figure 1 is a schematic diagram of the structure of the microscope objective of Embodiment 1 of this application.

[0009] Figure 2 is a schematic diagram of the wavefront aberration variation curve of the microscope objective in Figure 1 with an effective focal length of 8 mm across the entire field of view and wavelength range.

[0010] Figure 3 is a schematic diagram of the structure of the microscope objective of Embodiment 2 of this application.

[0011] Figure 4 is a schematic diagram of the wavefront aberration variation curve of the microscope objective in Figure 3 with an effective focal length of 10 mm across the entire field of view and wavelength range.

[0012] Figure 5 is a schematic diagram of the wavefront aberration variation curve of the microscope objective in Figure 3 with an effective focal length of 12 mm across the entire field of view and wavelength range.

[0013] Figure 6 is a schematic diagram of the structure of the microscopic optical detection system of Embodiment 3 of this application.

[0014] Figure 7 is a schematic diagram of the module structure of the sequencer in Embodiment 4 of this application.

[0015] Key Component Symbols: Sequencing Instrument 1; Microscopic Optical Detection System 100; Microscope Objectives 10; First Lens Group G1; Second Lens Group G2; Third Lens Group G3; Fourth Lens Group G4; Fifth Lens Group G5; First Lens L1; Second Lens L2; ​​Third Lens L3; Fourth Lens L4; Fifth Lens L5; Sixth Lens L6; Seventh Lens L7; Eighth Lens L8; Ninth Lens L9; Tenth Lens L10; First Negative Lens L11; Positive Lens L12; Second Negative Lens L13; Optical Surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22; Tube Lens 20; Image Sensor 30; Photosensitive Surface 31; Optical Assembly 40; Sequencing Chip 200; Optical System 300; Light Source 50; Optical Sensor 60 Image recognition device 400, biological sample 2, optical axis O

[0016] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0017] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0018] Numerous specific details are set forth in the following description to provide a thorough understanding of this application. The described embodiments are merely some, not all, of the embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0020] The microscope objectives provided in this application have both a large field of view and a large numerical aperture, which is beneficial for improving the resolution of the microscope objectives. When the microscope objectives are used in microscope optical inspection systems and sequencers, they can help reduce the cost of microscope optical inspection systems and sequencers.

[0021] Example 1

[0022] Please refer to Figure 1. The microscope objective 10 of Embodiment 1 of this application is used to acquire light signals from a biological sample 2 for imaging. The biological sample 2 may be, for example, a nucleic acid sample, a protein sample, or a cell sample. The microscope objective 10 may be applied, for example, to optical devices with a microscopic imaging system, such as gene sequencers.

[0023] The microscope objective 10 of this embodiment has a first lens group G1, a second lens group G2, a fourth lens group G4, a fifth lens group G5, a third lens group G3, and a positive lens L12 arranged in sequence from the object side to the image side, with a common optical axis O.

[0024] The first lens group G1 includes a first lens L1, a second lens L2, and a third lens L3 arranged sequentially from the object side to the image side. The first lens L1, the second lens L2, and the third lens L3 are all meniscus lenses. In this embodiment, the first lens L1 and the second lens L2 are spaced apart. In other embodiments of this application, the first lens L1 and the second lens L2 may also form a cemented doublet lens group.

[0025] The first lens group G1 has a positive optical power, and the first lens L1, the second lens L2, and the third lens L3 respectively have positive optical powers. The first lens L1 and the second lens L2 satisfy: 2.26 <= f2 / Fob j <= 2.82, where f2 is the combined focal length of the first lens L1 and the second lens L2, and Fob j is the effective focal length of the microscopic objective 100. The first lens L1 also satisfies: D1 / d1 < 0.74, where D1 is the effective clear aperture of the optical surface of the first lens L1 close to the object side, and d1 is the central thickness of the first lens L1. Through the above optical design, the first lens group G1 can be used to balance the field curvature of the microscopic objective 10 and reduce the spherical aberration and coma of the microscopic objective 10.

[0026] The second lens group G2 includes a second lens L4, a fifth lens L5, and a sixth lens L6 arranged in sequence from the object side to the image side. In this embodiment, the second lens group G2 is a three-piece cemented lens group, the second lens L4 and the sixth lens L6 are respectively convex lenses, and the fifth lens L5 is a biconcave lens.

[0027] In this embodiment, the second lens group G2 satisfies: 8.30 <= f3 / Fob j <= 12.49, where f3 is the focal length of the second lens group. The second lens group G2 is used to further承担 positive optical power on the basis of the first lens group G1 and is used to correct chromatic aberration.

[0028] The third lens group G3 includes at least one negative lens. In this embodiment, the third lens group G3 includes a first negative lens L11. The third lens group G3 satisfies: -0.7 < f5 / Fob j < -2, where f5 is the focal length of the third lens group G3 (which is also the first negative lens L11 in this embodiment). Further, the third lens group G3 and the positive lens L12 have an air gap d2 at the optical axis O, 0.18 < d2 / L < 0.3, where L is the total length of the microscopic lens 10. In other embodiments of the present application, the third lens group G3 may include a greater number of negative lenses. In the embodiments where the third lens group G3 includes a greater number of negative lenses, the combined focal length f5 of the third lens group G3 still satisfies -0.7 < f5 / Fob j < -2.

[0029] The fourth lens group G4 is located between the second lens group G2 and the third lens group G3. The fourth lens group G4 includes a seventh lens L7 and an eighth lens L8 arranged in sequence along the optical axis O of the microscopic objective 10 from the object side to the image side. In this embodiment, the fourth lens group G4 composed of the seventh lens L7 and the eighth lens L8 is a two-piece cemented lens. The fourth lens group G4 satisfies: 3.12 <= f4 / Fob j <= 3.77, where f4 is the focal length of the fourth lens group G4.

[0030] The fifth lens group G5 is located between the third lens group G3 and the fourth lens group G4, and includes a ninth lens L9 and a tenth lens L10 arranged in sequence along the optical axis O of the microscope objective 10 from the object side to the image side.

[0031] In this embodiment, the positive lens L12 is a meniscus lens, satisfying: 4.9 < f6 / Fobj < 10.18, where f6 is the focal length of the positive lens L12.

[0032] In this embodiment of the microscope objective 10, by setting the first lens group G1, the field curvature can be effectively balanced, and the spherical aberration and coma can be reduced as much as possible, so that the microscope objective 10 can have both a large field of view and a large numerical aperture. It improves the situation in the comparative example where the numerical aperture NA ≤ 0.8 when the object-side field of view of the microscope objective is ≤ 1.25 mm.

[0033] Moreover, since the microscope objective 10 can independently correct aberrations to reach the diffraction limit, when the microscope objective 10 is applied to an optical system, no other optical structures (such as tube lenses) in the optical system are required for compensation. This enables each component in the optical system (such as the microscope objective 10, tube lens) to independently test the optical characteristics, and also brings convenience to the replacement and matching of components in the optical system.

[0034] Furthermore, the microscope objective 10 in this embodiment can achieve a wavefront aberration below the diffraction limit within the full field and full bandwidth in the green to red wavelength band (540 nm - 770 nm), and achieve flat-field apochromatism. Thus, the image quality of the edge field of view of the microscope objective 10 tends to be consistent with that of the central field of view. When the microscope objective 10 is applied to an optical system based on an image sensor, a high-resolution image of the full field can be obtained.

[0035] In addition, the microscope objective 10 in this embodiment includes a total of 12 lenses (L1 - L12), with a compact overall structure, reasonable tolerance distribution, process feasibility, and stable and reliable imaging quality.

[0036] In this embodiment, the microscope objective 10 has a plurality of optical surfaces arranged in sequence from the object side to the image side: S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, and S20.

[0037] In this embodiment, the object-side numerical aperture of the microscope objective 10 ≤ 0.88, and the object-side medium space is successively: air medium, cover glass, and sample solution. The refractive index of the sample solution is between 1.3 - 1.36. Let the maximum semi-field height on the object side be Ho, and the focal length of the microscope objective 10 be Fob j Satisfying: Ho / Fob jWith a magnification of ≤0.076, it is suitable for microscope systems ranging from 10x to 100x. Taking the microscope objective 10 with a focal length of 8mm as an example, the maximum image-side half-field height (maximum object-side field of view multiplied by the magnification) can reach 76mm.

[0038] With the focal length Fob of microscope objective 10 j Taking 8mm as an example, in at least one optical design scheme of this embodiment, the optical design parameters of the microscope objective 10 are shown in Table 1 below. The spacing represents the distance between two adjacent optical surfaces at the optical axis O. If the two adjacent optical surfaces belong to the same lens (group), then the spacing represents the center thickness (thickness at the optical axis O) of the lens (group). It should be noted that all 12 lenses (L1-L12) in this application are glass lenses.

[0039] Table 1

[0040] In the above optical design scheme:

[0041] f2 / Fob j = 2.41, where f2 is the combined focal length of the first lens L1 and the second lens L2, Fob j The effective focal length of the objective lens;

[0042] f3 / Fob j =8.33, where f3 is the focal length of the second lens group G2;

[0043] f4 / Fob j =3.44, where f4 is the focal length of the fourth lens group G4;

[0044] f5 / Fob j = -0.77, where f5 is the focal length of the first negative lens L11;

[0045] f6 / Fob j =4.9, where f6 is the focal length of the positive lens L12;

[0046] d2 / L=0.195, d1 / D=0.733.

[0047] The microscope lens 10 of this embodiment can achieve a numerical aperture (NA) of 0.87 when the object-side field of view reaches 1.2 mm, realizing flat-field imaging across different wavelengths within the entire object-side field of view. Figure 2 exemplarily illustrates the wavefront aberration of the microscope lens 10 at wavelengths λ of 558 nm, 608 nm, 674 nm, 715 nm, and 770 nm across the entire field of view, as well as the comprehensive performance of the wavefront aberration at each wavelength. It can be seen that in this embodiment, the wavefront aberration of the microscope lens 10 across different wavelengths in the entire field of view is less than the diffraction limit.

[0048] The microscope objective 10 described in this application includes a first lens group G1, a second lens group G2, a third lens group G3, and a positive lens L12 arranged sequentially from the object side to the image side along the optical axis of the microscope objective 10. The first lens group G1 has positive optical power and includes a first lens L1 and a second lens L2 arranged sequentially from the object side to the image side, and the first lens L1 and the second lens L2 satisfy 2.26 <= f2 / Fob. j <= 2.82; the second lens group G2 has positive optical power, and the third lens group G3 includes at least one negative lens (L11). Thus, the aforementioned microscope objective 10 can possess both a large field of view and a large numerical aperture, which is beneficial for improving the resolution of the microscope objective 10. When the microscope objective 10 is applied to a microscopic optical inspection system and a sequencer, it can effectively improve the throughput and speed of the microscopic optical inspection system and the sequencer, and help reduce the cost of the microscopic optical inspection system and the sequencer.

[0049] Example 2

[0050] Referring to Figure 3, the main difference between the microscope objective 10 of this embodiment and the microscope objective 10 of Embodiment 1 is that the third lens group G3 in the microscope objective 10 of this embodiment includes a first negative lens L11 and a second negative lens L13 arranged sequentially from the object side to the image side. That is, in this embodiment, the third lens group G3 includes two negative lenses spaced apart, and the microscope objective 10 includes a total of 13 lenses. In addition, in this embodiment, the first lens L1 and the second lens L2 form a cemented doublet lens group.

[0051] In this embodiment, the microscope objective 10 has multiple optical surfaces arranged sequentially from the object side to the image side: S1, S2, S3, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S21, S22, S19 and S20.

[0052] In at least one optical design of Embodiment 2, the focal length Fob of the microscope objective 10 is... j =10mm, the optical design parameters of the microscope objective 10 are shown in Table 2 below. The spacing represents the distance between two adjacent optical surfaces at the optical axis O. If the two adjacent optical surfaces belong to the same lens (group), the spacing represents the center thickness (thickness at the optical axis O) of the lens (group).

[0053] Table 2

[0054] In the above optical design scheme:

[0055] f2 / Fob j = 2.36, where f2 is the combined focal length of the first lens L1 and the second lens L2, Fobj The effective focal length of microscope objective 10;

[0056] f3 / Fob j =9.21, where f3 is the focal length of the second lens group G2;

[0057] f4 / Fob j =3.15, where f4 is the focal length of the fourth lens group G4;

[0058] f5 / Fob j = -0.82, where f5 is the focal length of the third lens group G3;

[0059] f6 / Fob j =6.57, where f6 is the focal length of the positive lens L12;

[0060] d2 / L = 0.24, d1 / D = 0.72.

[0061] The microscope lens 10 of this embodiment achieves a numerical aperture (NA) of 0.83 while maintaining an object-side field of view of 1.54 mm, enabling flat-field imaging across different wavelengths within the entire object-side field of view. Figure 4 exemplarily illustrates the wavefront aberration of the microscope lens 10 at wavelengths λ of 558 nm, 608 nm, 715 nm, and 770 nm across the entire field of view, as well as the overall performance of the wavefront aberration at each wavelength. It can be seen that the wavefront aberration of the microscope lens 10 is less than the diffraction limit across different wavelengths within the entire field of view.

[0062] In another optical design scheme of Embodiment 2, the focal length Fob of the microscope objective 10 is... j =12mm, the optical design parameters of the microscope objective 10 are shown in Table 3 below. The spacing represents the distance between two adjacent optical surfaces at the optical axis O. If the two adjacent optical surfaces belong to the same lens (group), the spacing represents the center thickness (thickness at the optical axis O) of the lens (group).

[0063] Table 3

[0064] In the above optical design scheme:

[0065] f2 / Fob j = 2.37, where f2 is the combined focal length of the first lens L1 and the second lens L2, Fob j The effective focal length of microscope objective 10;

[0066] f3 / Fob j = 9.68, where f3 is the focal length of the second lens group G2;

[0067] f4 / Fobj =3.12, where f4 is the focal length of the fourth lens group G4;

[0068] f5 / Fob j = -0.81, where f5 is the focal length of the first negative lens L11;

[0069] f6 / Fob j =6.99, where f6 is the focal length of the positive lens L12;

[0070] d2 / L = 0.26, d1 / D = 0.71.

[0071] The microscope lens 10 of this embodiment can achieve a numerical aperture of 0.87 while maintaining an object-side field of view of 1.70 mm, thus realizing flat-field imaging across different wavelengths within the entire object-side field of view. Figure 5 exemplarily illustrates the wavefront aberration of the microscope lens 10 at wavelengths λ of 558 nm, 608 nm, 715 nm, and 770 nm across the entire field of view, as well as the comprehensive performance of the wavefront aberration at each wavelength. It can be seen that the wavefront aberration of the microscope lens 10 is less than the diffraction limit across different wavelengths within the entire field of view.

[0072] The microscope objective 10 of Embodiment 2 of this application can achieve all the beneficial effects of the microscope objective 10 of Embodiment 1, and will not be described again.

[0073] Example 3

[0074] This embodiment provides a microscopic optical detection system including any of the microscope objectives 10 described in Embodiments 1 and 2. Referring to Figure 6, the microscopic optical detection system 100 includes a microscope objective 10, a tube lens 20, and an image sensor 30, with the tube lens 20 located between the microscope objective 10 and the image sensor 30. The image sensor 30 has a sensing surface 31 facing the tube lens 20. The microscope objective 10 is used to acquire light signals from a biological sample 2, and the tube lens 20 is used to focus the light signals (e.g., fluorescence signals) from the microscope objective 10 onto the sensing surface 31. The image sensor 30 senses the light signals through the sensing surface 31 to form an image. The image sensor 30 can be an area array camera or a time-delay integration (TDI) camera. As shown in Figure 6, light signals of different wavelengths emitted by the biological sample 2 are focused onto different focusing positions on the sensing surface 31.

[0075] By adjusting the focal length of the tube lens 20, the overall magnification of the optical system composed of the microscope objective 10 and the tube lens 20 can be adjusted to meet the imaging needs of different scenarios. For example, in at least one embodiment of this application, by setting the focal length of the microscope objective 10 to 12mm and the focal length of the tube lens 20 to 200mm, a 16.67X microscopic optical inspection system can be obtained.

[0076] In this embodiment, the tube lens 20 includes a first cemented doublet lens group 21 and a second cemented doublet lens group 22 arranged at intervals. This helps to further compensate for transverse chromatic aberration and other residual higher-order aberrations of the microscope objective 10. In this embodiment, the parallel distance between the microscope objective 10 and the tube lens 20 is about 200 mm to facilitate the insertion of other optical elements 40, such as filters, dichroic mirrors, etc.

[0077] In this embodiment, the microscope objective 10 and the tube lens 20 can independently correct aberrations, each achieving a wavefront aberration less than the diffraction limit. There is no need for the tube lens 20 to compensate for aberrations in the microscope objective 10. This is beneficial for individually inspecting different optical components (such as the microscope objective 10 and the tube lens 20) during the optical path inspection process, and also for individually replacing optical components during the optical path construction process.

[0078] The microscopic optical detection system 100 of this embodiment can be applied in a sequencer to perform optical scanning and imaging of a biochip loaded with biological sample 2. In other embodiments of this application, the microscopic optical detection system 100 can also be used to detect other samples with coverslips, and is suitable for other imaging applications requiring a large field of view and high resolution, such as front-end manufacturing and back-end detection equipment for semiconductors, nanotechnology, biological microscopy, materials analysis, etc.

[0079] The microscopic optical inspection system 100 of this embodiment can be applied to various fluorescence microscopic optical devices. Since the microscope objective 10 can achieve both a large field of view and a large numerical aperture within a limited space and weight, the detection throughput and speed of the microscopic optical inspection system 100 including the microscope objective 10 are improved, and the cost of the microscopic optical inspection system 100 is reduced.

[0080] Example 4

[0081] This embodiment provides a sequencer. Referring to Figure 7, the sequencer 1 of this embodiment includes a sequencing chip 200 and an optical system 300 optically coupled to the sequencing chip 200. The surface of the sequencing chip 200 facing the optical system 300 is used to support the biological sample 2 to be tested. In this embodiment, the biological sample 2 is a nucleic acid sample (DNA or RNA), and the sequencer 1 is used to detect the base sequence of the biological sample 2. The optical system 300 is used to emit a light beam to the biological sample 2 and to collect the light beam from the biological sample 2 to achieve optical detection.

[0082] In this embodiment, the optical system 300 includes a microscope objective 10, a light source 50, and an optical sensor 60. The light source 50 is operatively optically coupled to the sequencing chip 200 to emit illumination light of a specified wavelength onto the biological sample 2 to be tested. The biological sample 2 to be tested generates a detectable light signal in response to the illumination light. The optical sensor 60 is coupled to the microscope objective 10 and acquires the detectable light signal via the microscope objective 10.

[0083] In this embodiment, the light source 50 includes an excitation light source for emitting excitation light, and the irradiation light includes the excitation light emitted by the excitation light source. For example, the light source 50 includes a laser for emitting monochromatic laser or multi-color laser, and the irradiation light includes red and / or green laser. When the irradiation light irradiates the biological sample 2, it can excite the fluorescent dye carried in the biological sample 2, causing the biological sample 2 to produce a fluorescence signal. That is, the detectable light signal includes the fluorescence signal generated by the excitation light on the biological sample 2 to be detected. In this embodiment, the optical sensor 60 includes a TDI camera, which acquires the fluorescence signal via the microscope objective 10.

[0084] In this embodiment, the sequencer 1 also includes an image recognition device 400, which is used to generate an image of the biological sample 2 based on the fluorescence signal and analyze the base sequence of the biological sample.

[0085] In this embodiment, the object-space medium of the microscopic optical detection system 100 in the sequencer 1 consists of air, a coverslip, and a sample solution, in sequence. The refractive index of the sample solution is between 1.3 and 1.36.

[0086] The pursuit of high throughput, high speed, and low cost is the development direction of next-generation sequencers. The resolution of a sequencer determines the information density it can process per unit time; therefore, high resolution leads to high throughput and high speed. Typically, sequencing costs consist of three main parts: instrument depreciation costs, sequencing reagent costs, and sequencing chip costs. Sequencing reagent costs and sequencing chip costs together account for more than 80% of the total cost. Therefore, reducing sequencing reagent costs and sequencing chip costs is usually the preferred approach to achieve overall sequencing cost reduction.

[0087] When considering reducing the cost of sequencing reagents and sequencing chips, the focus is typically on how to measure more DNA nanospheres (DNB points) within the same area of ​​the sequencing chip, or how to produce more DNB points on a sufficiently small sequencing chip (with minimal reagent loss). This aims to technically extend beyond Moore's Law and drive explosive growth in the application of sequencing technology in industries such as human health, animals, plants, and microorganisms. In short, the resolution of the optical system (including the microscopic optical detection system 100) in the sequencer is crucial to throughput, speed, and consumable costs.

[0088] However, the resolution of the microscope objective 10 is determined by the numerical aperture and wavelength. The numerical aperture NA = n*sinθ, where n is the refractive index of the object-side medium and θ is the object-side half-aperture angle of the objective. After the object-side half-aperture angle reaches its limit, increasing the refractive index of the object-side medium, i.e., immersing it in water or oil, becomes one way to improve the resolution. However, immersing the microscope objective 10 requires the addition of an additional medium, which brings a series of reliability issues.

[0089] Traditional large numerical aperture (NA) microscope objectives, typically used for high magnification, have large numerical apertures and high magnification, but extremely small object-side field of view. Objectives with NA > 0.8 rarely have an object-side field of view greater than 1 mm. Moreover, most commercially available objectives are used in visual systems and cannot achieve near-diffraction-limited sharpness across the entire imaging range.

[0090] Furthermore, the increasing reagent flow rates required by sequencers necessitate thicker coverslips for the sequencing chips used to mount biological samples, effectively increasing the working distance and adding design challenges. The field of view of a microscope objective, i.e., the object-space area that can be captured per unit time, is crucial. Given a fixed sequencing chip size, image sensor frame rate, and platform speed, a larger object-space field of view for the microscope objective results in fewer images or less time required to capture the entire sequencing chip.

[0091] Therefore, the sequencer 1 in this embodiment employs a microscope objective 10 that combines a large field of view and a large numerical aperture, thereby improving the resolution of the microscope objective 10, which in turn increases the sequencing throughput and sequencing speed of the sequencer 1. This helps to reduce consumables generated during the sequencing process and lower sequencing costs. Therefore, the microscope objective 10 in this embodiment, especially when applied to the sequencer 1, is of great significance for cost control of the sequencer 1.

[0092] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A microscope objective, characterized in that, Comprising a first lens group, a second lens group, a third lens group and a positive lens arranged in sequence along the optical axis of the microscope objective from the object side to the image side; The first lens group has positive optical power and includes a first lens and a second lens arranged sequentially from the object side to the image side. The first lens and the second lens satisfy: 2.26 <= f2 / Fob j <= 2.82, where f2 is the combined focal length of the first lens and the second lens, Fob j The effective focal length of the microscope objective is given. The second lens group has a positive optical power; The third lens group includes at least one negative lens.

2. The microscope objective as described in claim 1, characterized in that, The first lens satisfies: D1 / d1 < 0.74, where D1 is the effective clear aperture of the first lens near the object-side surface and d1 is the central thickness of the first lens.

3. The microscope objective as described in claim 1, characterized in that, The first lens and the second lens respectively have positive optical powers.

4. The microscope objective as described in claim 3, characterized in that, The first lens and the second lens are spaced apart and are respectively meniscus lenses.

5. The microscope objective as described in claim 3, characterized in that, The first lens and the second lens form a doublet lens group.

6. The microscope objective as described in claim 1, characterized in that, The second lens group is a triplet lens group, including two convex lenses and a biconcave lens located between the two convex lenses.

7. The microscope objective as described in claim 6, characterized in that, The second lens group satisfies: 8.30 <= f3 / Fob j <=12.49, where f3 is the focal length of the second lens group.

8. The microscope objective as described in claim 1, characterized in that, The third lens group satisfies: -0.7 <f5 / Fob j <-2, where f5 is the focal length of the third lens group.

9. The microscope objective as described in claim 1, characterized in that, It also includes a fourth lens group located between the second lens group and the third lens group, the fourth lens group satisfying: 3.12 <= f4 / Fob j <=3.77, where f4 is the focal length of the fourth lens group.

10. The microscope objective as claimed in claim 1, characterized in that, The third lens group and the positive lens have an air gap d2 at the optical axis, 0.18 < d2 / L < 0.3, where L is the total length of the microscope lens.

11. The microscope objective as claimed in claim 1, characterized in that, The positive lens is a meniscus lens, satisfying: 4.9 < f6 / Fobj < 10.18, where f6 is the focal length of the positive lens.

12. A microscopic optical inspection system, characterized in that, Comprising: The microscope objective, tube lens and image sensor according to any one of claims 1-11; The tube lens is located between the microscope objective and the image sensor. The image sensor has a photosensitive surface. The tube lens is used to focus the light beam from the microscope objective onto the photosensitive surface, and the image sensor is used to sense the light beam to form an image.

13. A sequencer, characterized in that, Comprising: A sequencing chip and an optical system optically coupled to the sequencing chip; The sequencing chip is used to support a biological sample to be detected; The optical system includes a microscope objective, a light source and an optical sensor; the light source is optically coupled to the sequencing chip operably to emit irradiation light of a specified wavelength to the biological sample to be detected, and the biological sample to be detected generates a detectable optical signal in response to the irradiation light; the optical sensor is coupled to the microscope objective to collect the detectable optical signal through the microscope objective; The microscope objective includes a first lens group, a second lens group, a third lens group, and a positive lens arranged sequentially from the object side to the image side along the optical axis of the microscope objective; the first lens group has positive optical power and includes a first lens and a second lens arranged sequentially from the object side to the image side, wherein the first lens and the second lens satisfy: 2.26 <= f2 / Fob j <= 2.82, where f2 is the combined focal length of the first lens and the second lens, Fob j The effective focal length of the microscope objective is given; the second lens group has positive optical power; the third lens group includes at least one negative lens.

14. The sequencer as described in claim 13, characterized in that, The light source is optically coupled to the microscope objective and projects the irradiation light towards the biological sample to be detected through the microscope objective.

15. The sequencer as described in claim 14, characterized in that, The light source includes an excitation light source, the irradiation light includes excitation light emitted by the excitation light source, and the detectable optical signal includes a fluorescence signal generated by the biological sample to be detected excited by the excitation light.

16. The sequencer as described in claim 15, characterized in that, The optical sensor includes a TDI camera, and the TDI camera collects the fluorescence signal through the microscope objective.

17. The sequencer as described in claim 13, characterized in that, The first lens satisfies: D1 / d1 < 0.74, where D1 is the effective clear aperture of the first lens near the object-side surface and d1 is the central thickness of the first lens.

18. The sequencer as described in claim 13, characterized in that, The first lens and the second lens respectively have positive optical powers.

19. The sequencer as described in claim 18, characterized in that... ,, The first lens and the second lens are spaced apart and are respectively meniscus lenses.

20. The sequencer as described in claim 18, characterized in that, The first lens and the second lens form a doublet lens group.

21. The sequencer as described in claim 13, characterized in that, The second lens group is a triplet lens group, including two convex lenses and a biconcave lens located between the two convex lenses.

22. The sequencer as described in claim 21, characterized in that, The second lens group satisfies: 8.30 <= f3 / Fob j <=12.49, where f3 is the focal length of the second lens group.

23. The sequencer as described in claim 13, characterized in that, The third lens group satisfies: -0.7 <f5 / Fob j <-2, where f5 is the focal length of the third lens group.

24. The sequencer as described in claim 13, characterized in that, It also includes a fourth lens group located between the second lens group and the third lens group, the fourth lens group satisfying: 3.12 <= f4 / Fob j <=3.77, where f4 is the focal length of the fourth lens group.

25. The sequencer as described in claim 13, characterized in that, The third lens group and the positive lens have an air gap d2 on the optical axis, where 0.18 < d2 / L < 0.3, and L is the total length of the microscope lens.

26. The sequencer as described in claim 13, characterized in that, The positive lens is a meniscus lens, satisfying: 4.9 < f6 / Fobj < 10.18, where f6 is the focal length of the positive lens.

Images