Cylindrical lens, fast automatic optical inspection system and method compatible with high na objective lens

Abstract

This invention relates to a tube lens compatible with high-NA objectives, a rapid automated optical inspection system and method. The tube lens includes a lens assembly comprising a first cemented lens with positive optical power, a second cemented lens with negative optical power, and a third cemented lens with positive optical power, arranged sequentially along the principal optical axis. The first cemented lens is disposed on one side of the object being tested. The first cemented lens comprises a first lens and a second lens cemented together; the second cemented lens comprises a third lens and a fourth lens cemented together; and the third cemented lens comprises a fifth lens and a sixth lens cemented together. The design of this invention enables a 1.4X tube lens, compatible with high-NA objectives. Its lens assembly includes multiple cemented lenses forming a positive-negative-positive structure, which improves the pixel resolution, optical resolution, and minimum defect size detection capability. It also has a long front working distance, adaptable to both vertical and horizontal inspection optical paths.

Description

Technical Field

[0001] This invention belongs to the field of optical element technology, and relates to microscope imaging equipment technology, specifically to a tube lens compatible with high NA objectives, a rapid automatic optical inspection system and method. Background Technology

[0002] A rapid automated optical inspection system typically consists of an objective lens, a telescope, and a camera. The objective lens and telescope project a high-quality image of the sample onto the camera's target surface to support rapid scanning of large-size sensors. Generally, an illumination and focusing module can be connected within the working range in front of the telescope, and a multi-channel imaging module can be connected within the working range behind it. The focusing module feeds back the optimal focal plane information to the moving axis, which then moves the optomechanical system to the optimal focal plane position for imaging. Therefore, focusing performance directly affects image quality.

[0003] Most typical telescope systems can only accommodate a single coaxial beam. A dichroic mirror and beam splitter are placed at the working distance in front of the telescope, and a beam splitter prism is placed at the working distance behind it to meet the focusing, illumination, and multi-channel inspection requirements of a rapid automated optical inspection system. Since these optical components are not incorporated into the design of typical telescopes for image quality optimization, the addition of a thicker beam splitter prism would degrade the system's image quality, making it unsuitable for the high-resolution requirements of rapid automated optical inspection.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a tube lens compatible with high-NA objectives, a rapid automatic optical inspection system, and a method.

[0006] The technical solutions adopted in the embodiments of the present invention are as follows: A tube lens compatible with high-NA objectives includes a lens assembly comprising a first cemented lens with positive optical power, a second cemented lens with negative optical power, and a third cemented lens with positive optical power arranged sequentially along the principal optical axis, wherein the first cemented lens is disposed on one side of the object being measured. The first cemented lens includes a first lens and a second lens cemented together, wherein the first lens is a meniscus negative lens and the second lens is a biconvex positive lens; The second cemented lens includes a third lens and a fourth lens cemented together, wherein the third lens is a positive lens and the fourth lens is a negative lens; The third cemented lens includes a fifth lens and a sixth lens cemented together, wherein the fifth lens is a positive meniscus lens and the sixth lens is a negative meniscus lens.

[0007] A further technical solution is that the focal length of the first cemented lens is fB1, the focal length of the second cemented lens is fB2, and the focal length of the third cemented lens is fB3, wherein 2.3≤|fB2 / fB1|≤2.5, 2.3≤|fB3 / fB2|≤2.5, and 5.3≤|fB3 / fB1|≤5.6.

[0008] A further technical solution is as follows: the first lens has a refractive index of n1 and an Abbe number of v1; the second lens has a refractive index of n2 and an Abbe number of v2; the third lens has a refractive index of n3 and an Abbe number of v3; the fourth lens has a refractive index of n4 and an Abbe number of v4; the fifth lens has a refractive index of n5 and an Abbe number of v5; and the sixth lens has a refractive index of n6 and an Abbe number of v6. 1.6≤n1≤1.8, 20≤v1≤40; 1.4≤n2≤1.6, 70≤v2≤90; 1.3≤n3≤1.5, 80≤v3≤100; 1.4≤n4≤1.6, 50≤v4≤70; 1.7≤n5≤1.9,20≤v5≤40;1.6≤n6≤1.8,20≤v6≤40。

[0009] A further technical solution is that the tube lens also includes a first prism located within the working distance in front of the lens assembly and a second prism located within the working distance behind the lens assembly; The surface of the first prism is provided with an illumination beam inlet and a focusing beam inlet, and the interior of the first prism is provided with a reflective surface and a first beam splitting surface. The reflective surface is configured to deflect the focusing beam and transmit the detection beam of a preset wavelength band, and the first beam splitting surface is configured to deflect the illumination beam and transmit the detection beam. The second prism has a second beam-splitting surface inside, and the first and second beam-splitting surfaces are configured to deflect and transmit a detection beam of a preset wavelength.

[0010] A further technical solution is that the first prism includes a first right-angle prism, a second right-angle prism, and a third right-angle prism, wherein the inclined surfaces of the first right-angle prism and the third right-angle prism are respectively glued to the opposite right-angle surfaces of the second right-angle prism; a narrow-band reflective film is deposited on the inclined surface of the first right-angle prism as the reflective surface; and a beam-splitting film is deposited on the inclined surface of the third right-angle prism as the first beam-splitting surface. The second prism includes a fourth right-angle prism and a fifth right-angle prism, wherein the inclined surface of the fourth right-angle prism is glued to the inclined surface of the fifth right-angle prism, and a beam-splitting film is deposited on the glued surface of the fourth right-angle prism and the fifth right-angle prism as the second beam-splitting surface.

[0011] A further technical solution is that the focal length of the tube lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, wherein 1.5≤|f1 / f|≤1.7, 2.1≤|f2 / f|≤2.3, 0.5≤|f3 / f|≤0.7, 0.4≤|f4 / f|≤0.6, 0.1≤|f5 / f|≤0.3, and 0.1≤|f6 / f|≤0.3.

[0012] A further technical solution is that the tube lens includes an objective lens, a pupil plane, an image plane, an imaging module, and a tube lens compatible with high-NA objectives. The pupil plane is the back focal plane of the objective lens, with a diameter compatible to 24mm and a field of view of 3.6°. The image plane has a diameter of 35mm and is suitable for visible light in the wavelength range of 430~680nm. The focal length of the tube lens is 280mm, and the front working distance is 281mm.

[0013] A rapid automated optical inspection system includes an objective lens, a focusing module, an illumination module, an imaging module, and a tube lens compatible with the aforementioned high-NA objective lens, wherein... The focusing module is equipped with a focusing sensor, the focusing beam inlet is configured to receive a narrow-band beam emitted by the focusing module, and the illumination beam inlet is configured to receive an illumination beam emitted by the illumination module. The target surface of the imaging module is positioned on the image surface, and the beam output from the tube lens forms a real image in the imaging module.

[0014] A method of using a rapid automated optical inspection system, applied to the system, the method comprising the following steps: Focusing: The narrow-band focusing beam emitted by the focusing module is received through the focusing beam inlet on the first prism. The focusing beam is deflected by the reflecting surface of the first prism to the object under test on the objective lens side. The focusing beam reaches the focusing sensor after being reflected by the surface of the object under test, the objective lens, and the reflecting surface of the first prism. The need for focusing is determined based on the quality of the focusing signal. Illumination: The illumination beam emitted by the illumination module is received through the illumination beam inlet on the first prism, and the illumination beam is deflected onto the object under test on one side of the objective lens through the first beam splitting surface of the first prism; Detection: The detection beam of the object being tested, collected by the objective lens, passes through the reflecting surface and the first beam splitting surface of the first prism, enters the lens assembly, and then passes through the first cemented lens, the second cemented lens, and the third cemented lens of the lens assembly in sequence. It then reaches the second prism, and through the deflection or transmission of the second prism, the detection beam is transmitted to the imaging module, which forms a real image of the object being tested.

[0015] The beneficial effects of the embodiments of the present invention are as follows: (i) The 1.4X tube lens proposed in this invention is compatible with high-NA objectives. Its lens assembly includes multiple cemented lenses, forming a corrected negative-positive structure, which can improve the pixel resolution, optical resolution, and minimum defect size detection capability of the image. This design has a long front working distance, which allows the first prism to be set within the front working distance. The interior of the first prism is equipped with a reflective surface and a first beam splitter with specific deflection and transmission functions, which facilitates the connection of the illumination module and the focusing module. The light path and beam adjustment are achieved through the first prism.

[0016] (ii) The rapid automatic optical inspection system proposed in this invention is equipped with the above-mentioned tube lens compatible with high NA objectives. Due to its long front working distance, it can be connected to optical modules such as autofocus and coaxial illumination, which can improve the pixel resolution of the imaging of the inspection system, improve the optical resolution and the ability to detect the minimum size of defects, and can also meet the optomechanical layout requirements of the inspection system for vertical inspection and horizontal inspection.

[0017] (III) The rapid automatic optical inspection method proposed in this invention, due to the configuration of optical modules such as automatic focusing and coaxial illumination, can automatically execute the focusing and inspection process, with a high degree of automation and high imaging resolution, and can be applied to optical inspection scenarios of various standard NA or high NA objectives. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a tube lens compatible with high NAND objective lenses provided in one embodiment of the present invention.

[0019] Figure 2 This is a field curvature data diagram of the tube lens provided in Embodiment 1 of the present invention.

[0020] Figure 3 This is a distortion data diagram of the tube lens provided in Embodiment 1 of the present invention.

[0021] Figure 4 This is a chromatic aberration data diagram of the tube lens provided in Embodiment 1 of the present invention.

[0022] Figure 5 The MTF curve of the tube lens provided in Embodiment 1 of the present invention is shown.

[0023] Figure 6 This is a schematic diagram of a planar telescope provided in Embodiment 2 of the present invention.

[0024] Figure 7 This is a schematic diagram of a rapid automatic detection optical system including the tube lens described in Embodiment 1, provided for Embodiment 3 of the present invention.

[0025] In the diagram: 1. Pupil plane; 2. First prism; 3. First cemented lens; 4. Second cemented lens; 5. Third cemented lens; 6. Second prism; 7. Image plane; 21. Focusing beam entrance; 22. Illumination beam entrance; 23. Reflecting surface; 24. First beam splitting surface; 61. Second beam splitting surface; 31. First lens; 32. Second lens; 41. Third lens; 42. Fourth lens; 51. Fifth lens; 52. Sixth lens. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the device proposed by this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0028] Example 1 Figure 1 This is a schematic diagram of the structure of a tube lens compatible with high-NA objectives provided in one embodiment of the present invention. Figure 1 As shown, the tube lens of this embodiment includes, in sequence: pupil plane 1, first prism 2, first cemented lens 3 with positive optical power, second cemented lens 4 with negative optical power, third cemented lens 5 with positive optical power, second prism 6, and image plane 7, wherein the curvature centers of the first prism 2, first cemented lens 3, second cemented lens 4, third cemented lens 5, second prism 6, and image plane 7 are located on the same optical axis, and the optical axis is perpendicular to the surface of each element.

[0029] Specifically, in this embodiment, the first cemented doublet 3 includes a first lens 31 with negative optical power and a second lens 32 with positive optical power, which are respectively a meniscus negative lens and a biconvex positive lens. The meniscus negative lens has a refractive index greater than 1.6 and an Abbe number less than 50, and is classified as flint glass. The biconvex positive lens has a refractive index less than 1.6 and an Abbe number greater than 50, and is classified as crown glass. This constitutes an achromatic cemented doublet lens group, which can achieve chromatic aberration correction over a wide spectral range.

[0030] The second cemented lens 4 includes a third lens 41 with positive optical power and a fourth lens 42 with negative optical power. The positive lens has a relatively low refractive index and a relatively high Abbe number; the negative lens has a relatively high refractive index and a relatively low Abbe number. Light incident and emitted light are relatively smooth.

[0031] The third cemented doublet 5 comprises a fifth lens 51 with positive optical power and a sixth lens 52 with negative optical power, employing positive and negative meniscus lenses respectively. This forms a positive Gaussian-type achromatic doublet with positive optical power, primarily serving to correct field curvature near the image plane 7. Both meniscus lenses are high-refractive-index, low-Abbe-number glass. Light travels from air to the high-refractive-index glass and then back to air; the change in refractive index causes a sudden change in the light transmission angle at the interface, thus correcting symmetrical aberrations. Cementing these two lenses together primarily reduces lens assembly deviations, minimizing the impact on asymmetrical aberrations.

[0032] Furthermore, the focal length of the first cemented lens 3 is fB1, the focal length of the second cemented lens 4 is fB2, and the focal length of the third cemented lens 5 is fB3, wherein 2.3≤|fB2 / fB1|≤2.5, 2.3≤|fB3 / fB2|≤2.5, and 5.3≤|fB3 / fB1|≤5.6.

[0033] Specifically, the focal length of the tube lens is f, the focal length of the first lens 31 is f1, the focal length of the second lens 32 is f2, the focal length of the third lens 41 is f3, the focal length of the fourth lens 42 is f4, the focal length of the fifth lens 51 is f5, and the focal length of the sixth lens 52 is f6, where 1.5≤|f1 / f|≤1.7, 2.1≤|f2 / f|≤2.3, 0.5≤|f3 / f|≤0.7, 0.4≤|f4 / f|≤0.6, 0.1≤|f5 / f|≤0.3, and 0.1≤|f6 / f|≤0.3.

[0034] Furthermore, the refractive index of the first lens 31 is n1, and the Abbe number of the first lens 31 is v1; the refractive index of the second lens 32 is n2, and the Abbe number of the second lens 32 is v2; the refractive index of the third lens 41 is n3. The Abbe number of the third lens 41 is v3; the refractive index of the fourth lens 42 is n4, and the Abbe number of the fourth lens 42 is v4; the refractive index of the fifth lens 51 is n5, and the Abbe number of the fifth lens 51 is v5; the refractive index of the sixth lens 52 is n6, and the Abbe number of the sixth lens 52 is v6, wherein 1.6≤n1≤1.8, 20≤v1≤40; 1.4≤n2≤1.6, 70≤v2≤90; 1.3≤n3≤1.5, 80≤v3≤100; 1.4≤n4≤1.6, 50≤v4≤70; 1.7≤n5≤1.9, 20≤v5≤40; 1.6≤n6≤1.8, 20≤v6≤40.

[0035] Furthermore, such as Figure 1 As shown, in this embodiment, the first prism 2 has two entrances: a focusing beam entrance 21 and an illumination beam entrance 22. The interior of the first prism 2 has a reflecting surface 23 arranged in the direction corresponding to the focusing beam entrance 21, as shown... Figure 1 The 45-degree reflective surface 23 in the middle allows for narrow-band reflection and wide-spectrum transmission, realizing the function of deflecting the focusing beam and transmitting the detection beam. The interior of the second prism 6 has a first beam-splitting surface 24 arranged in the direction corresponding to the illumination beam entrance 22, such as... Figure 1 The first beam splitter 24 at a 45-degree angle deflects the illumination beam and transmits the detection beam.

[0036] Specifically, the first prism 2 includes a first right-angle prism, a second right-angle prism, and a third right-angle prism, all with isosceles right-angled triangular cross-sections and appropriately sized, forming two continuous cubic prisms. The inclined surfaces of the first and third right-angle prisms are respectively cemented onto opposite right-angled faces of the second right-angle prism. A narrow-band reflective film is deposited on the inclined surface of the first right-angle prism as a reflecting surface 23, adjacent to the pupil surface 1. A beam-splitting film is deposited on the inclined surface of the third right-angle prism as a first beam-splitting surface 24, adjacent to the first cemented lens 3.

[0037] In general systems, focusing beam deflection is achieved through beam splitters with specific coatings. In applications with large-size beam splitters, it is difficult to guarantee the beam splitter's surface shape during fabrication and installation, thus affecting the wavefront aberration of the reflected and transmitted beams, impacting the focusing beam quality and focusing effect, and consequently affecting imaging performance and defect detection rate. In this embodiment, the first prism 2 has a coating layer deposited on the inclined surface of a right-angle prism, and then a right-angled triangular prism of the same shape is cemented together to form a cubic prism. The cubic prism makes it easier to guarantee a high-precision surface shape during fabrication and installation, thereby ensuring the wavefront aberration of the transmitted and reflected beams, achieving excellent focusing performance, and is more suitable for inspecting wafers with complex patterns.

[0038] Specifically, the second prism 6 includes a fourth right-angled prism and a fifth right-angled prism, both with isosceles right-angled triangular cross-sections and appropriately sized. The inclined surface of the fourth right-angled prism is cemented onto the inclined surface of the fifth right-angled prism. A beam-splitting film is deposited on the cemented surface of the fourth and fifth right-angled prisms, serving as the second beam-splitting surface 61. The second prism 6 achieves the deflection and transmission of the detection beam. This design constitutes a cubic beam-splitting prism, which effectively protects the film layer from oxidation, corrosion, and scratches. The integration of the second prism 6 enables the dual-channel imaging function of the rapid automatic detection system, making the system more versatile.

[0039] In this embodiment, the pupil plane 1 refers to the back focal plane of the objective lens adapted to the tube lens. The diameter of the pupil plane 1 varies depending on the objective lens specifications, with a maximum compatibility of 24mm. It is compatible with both standard NA and high NA objectives, improving imaging resolution; it is also compatible with wide field-of-view objectives, increasing line scan speed. The tube lens integrates a positive-negative-positive lens assembly, a first prism 2, and a second prism 6, allowing for simultaneous Zemax optimization and tolerance analysis. This ensures image quality across the wide field of view and reduces the impact of prism manufacturing and assembly tolerances on the final image quality. The image-side field of view reaches 35mm.

[0040] The tube lens designed in this embodiment is suitable for optical signals in the 430-680nm band. The focal length of the tube lens is 280mm, the diameter of the pupil plane 1 is compatible with up to 24mm (including 24mm), the field of view can reach 3.6°, the front working distance can reach 281mm, and the size of the image plane 7 can support up to 35mm.

[0041] Figure 2 This is a field curvature data diagram of the tube lens provided in Embodiment 1 of the present invention. Figure 3 This is a distortion data diagram of the tube lens provided in Embodiment 1 of the present invention. Figure 4 This is a chromatic aberration data diagram of the tube lens provided in Embodiment 1 of the present invention. In the application of the tube lens compatible with high and low NA objectives in this embodiment, the light beam from the pupil plane 1 enters the tube lens through the first prism 2. The tube lens is composed of three sets of cemented doublet lenses. The first cemented lens 3 has positive optical power, the second cemented lens 4 has negative optical power, and the third cemented lens 5 has positive optical power. This combination of positive and negative positive optical power rationally distributes the system's optical power, resulting in a smoother beam path. While ensuring image quality, the tube lens achieves a focal length of 280 mm and a field of view of 35 mm, and astigmatism, field curvature, distortion, and chromatic aberration are well corrected across the entire field of view. Figure 2 , Figure 3 and Figure 4 As shown.

[0042] After passing through the tube lens, the light reaches the second prism 6, where it is deflected and transmitted through the second beam-splitting surface 61, enabling dual-channel imaging to meet different user detection needs. The tube lens system incorporates two beam-splitting prisms for optimization, ensuring image quality across the entire field of view.

[0043] Figure 5 This is an MTF curve of the tube lens provided in Embodiment 1 of the present invention. Under high NA (numerical aperture) objectives, its MTF is better than 0.3 at 90 lp / mm. Figure 5 As shown, the resolution requirements are met. Table 1 shows the tube lens design parameters.

[0044] Table 1. Tube Lens Design Parameters The parameters provided in Table 1 can be used as a reference for the selection and design of the telescope.

[0045] Example 2 Figure 6 This is a schematic diagram of a planar telescope according to Embodiment 2 of the present invention. The main differences from Embodiment 1 are the placement of the object under test and the objective lens, and the structure of the first prism 2. Embodiment 1 established a vertical detection optical path, where the object under test collects the light beam through the objective lens and then passes through the telescope to the image plane 7. This embodiment establishes a horizontal detection optical path, where the light beam collected by the objective lens is deflected by 90 degrees by the first prism 2 before passing through the telescope system to the image plane 7.

[0046] Specifically, provided that the overall weight of the telescope and its rapid automatic inspection system meets the system load requirements, the vertical installation method described in Embodiment 1 can be adopted. When the overall weight of the telescope and its rapid automatic inspection system exceeds the system load requirements, this system can also be modified into the horizontal structure described in Embodiment 2.

[0047] In this embodiment, the first prism 2 is provided with an illumination beam inlet 22 and a corresponding first beam-splitting surface 24, but not with a focusing beam inlet 21 and a reflecting surface 23. The tube lens receives the illumination beam through the illumination beam inlet 22 and deflects the illumination beam through the first beam-splitting surface 24, thus achieving a flat-lying configuration. By changing the coating type of the first beam-splitting surface 24 in the second prism 2, the optical axis of the beam can be deflected, thereby transforming the tube lens and its rapid automatic detection system into a flat-lying system. Because the tube lens of this invention has a large front working distance, a thicker dichroic mirror can be added between the first prism 2 and the objective lens to facilitate the connection of the focusing assembly.

[0048] Example 3 Figure 7 This is a schematic diagram of a rapid automatic detection optical system for the tube lens described in Embodiment 1, provided as a third embodiment of the present invention. Figure 7 As shown, the system includes: an objective lens, an image plane 7, a focusing module 8, an illumination module 9, an imaging module, and a tube lens compatible with high-NA objectives as proposed in Embodiment 1 or 2. The pupil plane 1 is the back focal plane of the objective lens, with a diameter compatible to 24 mm and a field of view of 3.6°. The image plane 7 has a diameter of 35 mm, and the lens target surface of the imaging module is positioned on the image plane 7. The focusing module 8 is equipped with a focusing sensor capable of emitting and receiving a focusing beam, and the illumination module 9 is equipped with a light source capable of emitting an illumination beam. The focusing beam inlet 21 is configured to receive a narrow-band beam emitted by the focusing module 8, and the illumination beam inlet 22 is configured to receive an illumination beam emitted by the illumination module 9. The beam output from the tube lens forms a real image in the imaging module.

[0049] The method of using the rapid automatic detection optical system in this embodiment includes the following steps: 1. Focusing operation: The narrow-band beam emitted by the focusing module 8 is received through the focusing beam inlet 21; The narrow-band beam is deflected by the reflecting surface 23 onto the object being measured on one side of the objective lens; The surface of the object being measured reflects the backfocusing beam back to the first prism 2; The focusing beam passes sequentially through the objective lens and the first prism 2 to reach the focusing sensor; The position of the detection system is adjusted based on the focusing signal fed back by the focusing sensor; 2. Lighting operation: The illumination beam emitted by the illumination module 9 is received through the illumination beam inlet 22; The illumination beam is deflected by the first beam splitter 24 onto the object under test on one side of the objective lens, and the beam is uniformly illuminating the object under test, providing uniform illumination for sample detection.

[0050] 3. Testing Procedure: The detection beam of the object being tested, collected by the objective lens, passes through the reflective surface 23 and the first beam-splitting surface 24 and enters the lens assembly.

[0051] The detection beam passes sequentially through the first cemented lens 3, the second cemented lens 4, and the third cemented lens 5 of the lens assembly, and then reaches the second prism 6.

[0052] The detection beam is deflected or transmitted through the second prism 6 and then transmitted to the imaging module, which forms a real image of the object under test.

[0053] Specifically, the imaging module includes an image receiving unit such as a camera. The detection beam travels from the pupil plane 1 through the tube lens system to the image receiving unit, which converts the optical signal into an electrical signal and outputs an image, thus forming a rapid optical detection system. The system is equipped with the aforementioned 1.4X tube lens, thereby improving pixel resolution under the same camera conditions. The tube lens pupil size is 24mm, making it compatible with both standard NA and high NA objectives.

[0054] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A tube lens compatible with high-NA objectives, characterized in that: The lens assembly includes a first cemented lens (3) with positive optical power, a second cemented lens (4) with negative optical power, and a third cemented lens (5) with positive optical power arranged sequentially along the principal optical axis. The first cemented lens (3) is disposed on one side of the object being measured. The first cemented lens (3) includes a first lens (31) and a second lens (32) cemented together. The first lens (31) is a meniscus negative lens, and the second lens (32) is a biconvex positive lens. The second cemented lens (4) includes a third lens (41) and a fourth lens (42) cemented together, wherein the third lens (41) is a positive lens and the fourth lens (42) is a negative lens; The third cemented lens (5) includes a fifth lens (51) and a sixth lens (52) cemented together. The fifth lens (51) is a positive meniscus lens, and the sixth lens (52) is a negative meniscus lens.

2. The tube lens compatible with high-NA objectives as described in claim 1, characterized in that: The focal length of the first cemented lens (3) is fB1, the focal length of the second cemented lens (4) is fB2, and the focal length of the third cemented lens (5) is fB3, wherein 2.3≤|fB2 / fB1|≤2.5, 2.3≤|fB3 / fB2|≤2.5, and 5.3≤|fB3 / fB1|≤5.

6.

3. The tube lens compatible with high-NA objectives as described in claim 2, characterized in that: The first lens (31) has a refractive index of n1 and an Abbe number of v1; the second lens (32) has a refractive index of n2 and an Abbe number of v2; the third lens (41) has a refractive index of n3 and an Abbe number of v3; the fourth lens (42) has a refractive index of n4 and an Abbe number of v4; the fifth lens (51) has a refractive index of n5 and an Abbe number of v5; and the sixth lens (52) has a refractive index of n6 and an Abbe number of v6. 1.6≤n1≤1.8, 20≤v1≤40; 1.4≤n2≤1.6, 70≤v2≤90; 1.3≤n3≤1.5, 80≤v3≤100; 1.4≤n4≤1.6, 50≤v4≤70; 1.7≤n5≤1.9,20≤v5≤40;1.6≤n6≤1.8,20≤v6≤40。 4. The tube lens compatible with high-NA objectives as described in claim 1, characterized in that: The tube lens also includes a first prism (2) located within the working distance in front of the lens assembly and a second prism (6) located within the working distance behind the lens assembly. The surface of the first prism (2) is provided with an illumination beam inlet (22) and a focusing beam inlet (21). The interior of the first prism (2) is provided with a reflective surface (23) and a first beam splitting surface (24). The reflective surface (23) is configured to deflect the focusing beam and transmit the detection beam of a preset wavelength band. The first beam splitting surface (24) is configured to deflect the illumination beam and transmit the detection beam. The second prism (6) has a second beam splitting surface (61) inside, and the first beam splitting surface (24) and the second beam splitting surface (61) are configured to deflect and transmit a detection beam of a preset wavelength.

5. The tube lens compatible with high NAND objectives as described in claim 4, characterized in that: The first prism (2) includes a first right-angle prism, a second right-angle prism, and a third right-angle prism. The inclined surfaces of the first right-angle prism and the third right-angle prism are respectively glued to the opposite right-angle surfaces of the second right-angle prism. A narrow-band reflective film is coated on the inclined surface of the first right-angle prism as the reflective surface (23). A beam-splitting film is coated on the inclined surface of the third right-angle prism as the first beam-splitting surface (24). The second prism (6) includes a fourth right-angle prism and a fifth right-angle prism, wherein the inclined surface of the fourth right-angle prism is glued to the inclined surface of the fifth right-angle prism, and a beam-splitting film is deposited on the glued surface of the fourth right-angle prism and the fifth right-angle prism as the second beam-splitting surface (61).

6. The tube lens compatible with high-NA objectives as described in claim 4, characterized in that: The focal length of the tube lens is f, the focal length of the first lens (31) is f1, the focal length of the second lens (32) is f2, the focal length of the third lens (41) is f3, the focal length of the fourth lens (42) is f4, the focal length of the fifth lens (51) is f5, and the focal length of the sixth lens (52) is f6, wherein 1.5≤|f1 / f|≤1.7, 2.1≤|f2 / f|≤2.3, 0.5≤|f3 / f|≤0.7, 0.4≤|f4 / f|≤0.6, 0.1≤|f5 / f|≤0.3, and 0.1≤|f6 / f|≤0.

3.

7. The tube lens compatible with high NAND objectives as described in claim 4, characterized in that: The tube lens includes a pupil plane (1), a first prism (2), a lens assembly, a second prism (6), and an image plane (7) arranged in sequence. The pupil plane (1) is the back focal plane of the objective lens. The diameter of the pupil plane (1) is compatible with up to 24 mm and the field of view is up to 3.6°. The diameter of the image plane (7) is 35 mm and it is suitable for visible light in the wavelength range of 430~680 nm. The focal length of the tube lens is 280 mm and the front working distance is up to 281 mm.

8. A rapid automatic optical inspection system, characterized in that... The detection branch includes an objective lens, a tube lens compatible with any of the high NA objectives as described in claims 1 to 7, and an imaging module.

9. The rapid automatic optical inspection system as described in claim 8, characterized in that: It also includes a focusing module (8) and an illumination module (9), wherein, The focusing module (8) is equipped with a focusing sensor, the focusing beam inlet (21) is configured to receive the narrow-band beam emitted by the focusing module (8), and the illumination beam inlet (22) is configured to receive the illumination beam emitted by the illumination module (9); The target surface of the imaging module is positioned on the image surface (7), and the beam output by the tube lens forms a real image in the imaging module.

10. A method of using a rapid automatic optical inspection system, characterized in that, When applied to the system of claim 9, the method of use includes the following steps: Focusing: The narrow-band focusing beam emitted by the focusing module (8) is received through the focusing beam inlet (21) on the first prism (2). The focusing beam is deflected by the reflecting surface (23) of the first prism (2) to the object under test on the objective lens side. The focusing beam reaches the focusing sensor after being reflected by the surface of the object under test, the objective lens, and the reflecting surface (23) of the first prism (2). The need for focusing is determined based on the quality of the focusing signal. Illumination: The illumination beam emitted by the illumination module (9) is received through the illumination beam inlet (22) on the first prism (2), and the illumination beam is deflected to the object under test on one side of the objective lens through the first beam splitting surface (24) of the first prism (2); Detection: The detection beam of the object being tested, collected by the objective lens, passes through the reflecting surface (23) and the first beam splitting surface (24) of the first prism (2), enters the lens assembly, and then passes through the first cemented lens (3), the second cemented lens (4) and the third cemented lens (5) of the lens assembly in sequence, and then reaches the second prism (6). Through the deflection or transmission of the second prism (6), the detection beam is transmitted to the imaging module, and the imaging module forms a real image of the object being tested.

Images