Object space telecentric imaging optical system and position alignment device

Abstract

The invention discloses an object space telecentric imaging optical system and a position alignment device.The object space telecentric imaging optical system comprises an imaging system and an illumination system, and the imaging system is provided with an object side and an image side which are oppositely arranged in the optical axis direction; the object space telecentric imaging optical system is composed of a first lens, a second lens, a third lens, a beam splitter prism, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from the object side to the image side. The illumination system comprises a light source, the light source is arranged corresponding to the beam splitter prism and is used for emitting an illumination light beam, the illumination light beam is reflected by the beam splitter prism and then illuminates the imaging system, through mutual combination of different lenses and reasonable distribution of positive and negative focal power, the magnification factor is increased, distortion is reduced, and high illumination uniformity and low cost are provided.

Description

Technical Field

[0001] The invention relates to the field of optical technology, and in particular to an object-side telecentric imaging optical system and a position alignment device. Background Art

[0002] In semiconductor packaging lithography equipment and flat panel display lithography, the position alignment device is one of the most important devices. From a structural point of view, the position alignment device can be divided into two categories: on-axis position alignment device and off-axis position alignment device. The use of off-axis position alignment device can reduce the design, processing and calibration requirements of the optical projection system. Its alignment method is often achieved by a measurement method based on machine vision technology. Among them, the imaging lens is one of the core components of the machine vision system. The quality of its optical performance will directly determine the accuracy of the final alignment measurement.

[0003] Generally speaking, high-precision measurement optical systems need to ensure image sharpness and a large magnification, while also ensuring that the illumination uniformity is less than 5% and the distortion is preferably less than 0.1%. Currently, most products on the market are 5X, have a large number of lenses, and are relatively expensive. Summary of the invention

[0004] The main purpose of the present invention is to propose an object-space telecentric imaging optical system, aiming to increase magnification, reduce distortion, and provide high illumination uniformity and low cost.

[0005] To achieve the above object, the present invention proposes an object-side telecentric imaging optical system, comprising:

[0006] An imaging system, wherein the object-side telecentric imaging optical system has an object side and an image side that are arranged opposite to each other along an optical axis direction, and the object-side telecentric imaging optical system is composed of a first lens, a second lens, a third lens, a beam splitter prism, a fourth lens, a fifth lens, and a sixth lens that are sequentially arranged from the object side to the image side;

[0007] An illumination system, comprising a light source, the light source being arranged corresponding to the beam splitter prism, for emitting an illumination light beam, and illuminating the imaging system after being reflected by the beam splitter prism;

[0008] Wherein, the first lens has positive optical power, the object side surface is convex, and the image side surface is convex;

[0009] The second lens has positive power, an object side surface is convex, and an image side surface is convex;

[0010] The third lens has negative optical power, the object side surface is concave, and the image side surface is concave;

[0011] The fourth lens has positive refractive power, an object side surface is convex, and an image side surface is convex;

[0012] The fifth lens has positive refractive power, the object side surface is concave, and the image side surface is concave;

[0013] The sixth lens has positive refractive power, an object-side surface is concave, and an image-side surface is convex.

[0014] In one embodiment, the focal length of the object-side telecentric imaging optical system 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, and the following relationships are satisfied: 1.7<|f1 / f|<1.9, 1.9<|f2 / f|<2.1, 1.5<|f3 / f|<1.7, 4.5<|f4 / f|<4.7, 1.0<|f5 / f|<1.3, 6.1<|f6 / f|<6.3.

[0015] In one embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are glass spherical lenses.

[0016] In one embodiment, the focal length of the object-side telecentric imaging optical system is f, the total optical length of the object-side telecentric imaging optical system is TTL, and the following conditions are satisfied:

[0017] 11.5 <TTL / f<12,150mm<TTL<170mm。

[0018] In one embodiment, the image-side numerical aperture of the object-side telecentric imaging optical system is NA, the aperture value is F, and the following conditions are satisfied:

[0019] NA≥0.12,33.1≤F<33.5.

[0020] In one embodiment, the refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, and the refractive index of the sixth lens is n6, and the following conditions are satisfied: 1.44 <n1<1.56,1.44<n2<1.56,1.55<n3<1.7,1.45<n4<1.6,1.45<n5<1.6,1.5<n6<1.65。

[0021] In one embodiment, the Abbe number of the first lens is v1, the Abbe number of the second lens is v2, the Abbe number of the third lens is v3, the Abbe number of the fourth lens is v4, the Abbe number of the fifth lens is v5, and the Abbe number of the sixth lens is v6, and the following conditions are satisfied: 63.0 <v1<64.0,63.0<v2<64.0,36.0<v3<37.0,70.0<v4<71.0,81.0<v5<82.0,40.0<v6<41.0。

[0022] In one embodiment, the thickness of the first lens is G1, the thickness of the second lens is G2, the thickness of the third lens is G3, the thickness of the fourth lens is G4, the thickness of the fifth lens is G5, and the thickness of the sixth lens is G6, and the following conditions are satisfied:

[0023] 2mm <G1<5mm,2mm<G2<5mm,0.8mm<G3<3mm,1mm<G4<3mm,1mm<G5<3mm,2mm<G6<4mm。

[0024] In one embodiment, the object side surface of the first lens has a curvature radius of R2, and the image side surface has a curvature radius of R3, the object side surface of the second lens has a curvature radius of R4, and the image side surface has a curvature radius of R5, the object side surface of the third lens has a curvature radius of R6, and the image side surface has a curvature radius of R7, the object side surface of the fourth lens has a curvature radius of R9, and the image side surface has a curvature radius of R10, the object side surface of the fifth lens has a curvature radius of R11, and the image side surface has a curvature radius of R12, the object side surface of the sixth lens has a curvature radius of R13, and the image side surface has a curvature radius of R14, and the following conditions are satisfied:

[0025] 110mm <R2<130mm,-25mm<R3<-10mm,15mm<R4<40mm,-45mm<R5<-28mm,-30mm<R6<-15mm,45mm<R7<65mm,35mm<R9<55mm,-145mm<R10<-125mm,-20mm<R11<-8mm,45mm<R12<65mm,-40mm<R13<-25mm,-30mm<R14<-15mm。

[0026] The present invention also provides a position alignment device, comprising an object-side telecentric imaging optical system, including:

[0027] An imaging system, wherein the object-side telecentric imaging optical system has an object side and an image side that are arranged opposite to each other along an optical axis direction, and the object-side telecentric imaging optical system is composed of a first lens, a second lens, a third lens, a beam splitter prism, a fourth lens, a fifth lens, and a sixth lens that are sequentially arranged from the object side to the image side;

[0028] An illumination system, comprising a light source, the light source being arranged corresponding to the beam splitter prism, for emitting an illumination light beam, and illuminating the imaging system after being reflected by the beam splitter prism;

[0029] Wherein, the first lens has positive optical power, the object side surface is convex, and the image side surface is convex;

[0030] The second lens has positive power, an object side surface is convex, and an image side surface is convex;

[0031] The third lens has negative optical power, the object side surface is concave, and the image side surface is concave;

[0032] The fourth lens has positive refractive power, an object side surface is convex, and an image side surface is convex;

[0033] The fifth lens has positive refractive power, the object side surface is concave, and the image side surface is concave;

[0034] The sixth lens has positive refractive power, an object-side surface is concave, and an image-side surface is convex.

[0035] In the technical solution of the present invention, the imaging system constitutes an object-side telecentric system, which can provide stable imaging quality within a wide working distance range, ensure a constant magnification, and meet the requirements of precision detection. By setting the first lens with positive focal length, the light collection effect is improved, thereby providing a large field of view. By setting the first lens with positive focal length, the second lens with positive focal length, and the third lens with negative focal length, the spherical aberration and chromatic aberration of the system are well corrected. After the parallel light is transmitted through the beam splitter prism, the fourth lens with positive focal length is set to further converge the parallel light. The field curvature and astigmatism of the system are jointly corrected by the fifth lens with double concave and positive focal length and the sixth lens with concave and convex and positive focal length, thereby improving the imaging quality. By comprehensively setting the focal length of each lens, the object-side telecentric imaging optical system can well control the light trend, reduce distortion while introducing more light, correct spherical aberration and coma, and increase the magnification, reduce distortion, and provide high illumination uniformity and low cost by combining different lenses and reasonably allocating positive and negative focal lengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0037] Figure 1 A schematic structural diagram of an embodiment of an object-side telecentric imaging optical system provided by the present invention;

[0038] Figure 2 for Figure 1 A schematic diagram of an MTF curve of an embodiment of a telecentric imaging optical system in the object side;

[0039] Figure 3 for Figure 1 A schematic diagram of a TFM of an embodiment of a telecentric imaging optical system in the object side;

[0040] Figure 4 for Figure 1 A point diagram of an embodiment of a telecentric imaging optical system in the object side;

[0041] Figure 5 for Figure 1 A schematic diagram of field curvature / distortion of an embodiment of a telecentric imaging optical system in the object side;

[0042] Figure 6 for Figure 1 Uniformity simulation diagram of an embodiment of a telecentric imaging optical system in the object side.

[0043] Description of Figure Numbers:

[0044] 100. Object-side telecentric imaging optical system; 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Object plane; 8. Beam splitter; 9. Image plane; 10. Light source.

[0045] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] The present invention provides an object-space telecentric imaging optical system 100 .

[0050] First of all, it is important to understand that the focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. The focal power can be used to characterize a certain refractive surface of a lens, a certain lens, or a system formed by multiple lenses.

[0051] See also Figure 1In one embodiment of the present invention, the object-side telecentric imaging optical system 100 includes an imaging system and an illumination system. The imaging system has an object side and an image side that are arranged opposite to each other along the optical axis. The object-side telecentric imaging optical system 100 is composed of a first lens 1, a second lens 2, a third lens 3, a beam splitter prism 8, a fourth lens 4, a fifth lens 5, and a sixth lens 6 that are sequentially arranged from the object side to the image side. The illumination system includes a light source 10, and the light source 10 is arranged corresponding to the beam splitter prism 8 to emit an illumination beam, and the light beam is emitted by the beam splitter prism 8. The prism 8 illuminates the imaging system after reflection, wherein the first lens 1 has positive optical power, the object side surface is convex, and the image side surface is convex; the second lens 2 has positive optical power, the object side surface is convex, and the image side surface is convex; the third lens 3 has negative optical power, the object side surface is concave, and the image side surface is concave; the fourth lens 4 has positive optical power, the object side surface is convex, and the image side surface is convex; the fifth lens 5 has positive optical power, the object side surface is concave, and the image side surface is concave; the sixth lens 6 has positive optical power, the object side surface is concave, and the image side surface is convex.

[0052] It should be noted that the object-side telecentric system means that the light on the object side enters the system almost parallel to the optical axis, that is, the angle of incidence is close to zero, which means that even if the position of the object changes, the image size will not be affected. This design ensures that no matter how the object moves along the optical axis within a certain range, its image size remains unchanged, thereby achieving a constant magnification. For the imaging system, by such a setting, the imaging system constitutes an object-side telecentric system, which can provide stable imaging quality within a wide working distance range, ensure a large and constant magnification, and meet the requirements of precision detection.

[0053] In addition, the beam splitter 8 can be a non-polarized beam splitter prism 8, with a reflection-transmittance ratio of 1:1. The light source 10 is located above the beam splitter prism 8, and the line connecting the light source 10 and the beam splitter prism 8 is perpendicular to the optical axis, and is used to emit an illumination beam; the illumination beam is a parallel light source 10 after passing through a light spot homogenizer, and after being reflected by the beam splitter prism 8, it forms Kohler illumination to illuminate the object plane 7, thereby improving the illumination uniformity. The illuminated object plane 7 reflects the parallel light, and passes through the first lens 1, the second lens 2, the third lens 3, the beam splitter prism 8, the fourth lens 4, the fifth lens 5, and the sixth lens 6 in sequence parallel to the optical axis, and finally forms an image on the image plane 9. Among them, by setting the first lens 1 with positive optical focal length, the second lens 2 with positive optical focal length, and the third lens 3 with negative optical focal length, the spherical aberration and chromatic aberration of the system are well corrected; after the parallel light is transmitted through the dichroic prism 8, the fourth lens 4 with positive optical focal length is set to further converge the parallel light, and the field curvature and astigmatism of the system are jointly corrected by the fifth lens 5 with double concave and positive optical focal length and the sixth lens 6 with concave and convex and positive optical focal length, so as to improve the imaging quality; on the other hand, since only six lenses are used, the cost is saved.

[0054] In the technical solution of the present invention, the imaging system constitutes an object-side telecentric system, which can provide stable imaging quality within a wide working distance range, ensure a constant magnification, and meet the requirements of precision detection. By setting the first lens 11 with positive focal length, the light collection effect is improved, thereby providing a large field of view. By setting the first lens 1 with positive focal length, the second lens 2 with positive focal length, and the third lens 3 with negative focal length, the spherical aberration and chromatic aberration of the system are well corrected. When the parallel light is transmitted through the beam splitter prism 8, by setting the The fourth lens 4 with positive optical power further converges the parallel light, and the field curvature and astigmatism of the system are jointly corrected by the fifth lens 5 with double concave and positive optical power and the sixth lens 6 with concave and convex and positive optical power to improve the imaging quality; by comprehensively setting the optical power of each lens, the object-side telecentric imaging optical system 100 can well control the trend of light, reduce distortion while introducing more light, correct spherical aberration and coma, and by combining different lenses and reasonably allocating positive and negative optical power, the magnification is increased, the distortion is reduced, and high illumination uniformity and low cost are provided.

[0055] In an embodiment of the present invention, it should be understood that the focal length refers to the distance from the rear surface of the lens to the image plane 9 in an optical system. The focal length determines the magnification and viewing angle of the image. The optical power is the reciprocal of the focal length. The focal length of the object-side telecentric imaging optical system 100 is f, the focal length of the first lens 1 is f1, the focal length of the second lens 2 is f2, the focal length of the third lens 3 is f3, the focal length of the fourth lens 4 is f4, the focal length of the fifth lens 5 is f5, and the focal length of the sixth lens 6 is f6, and the following relationships are satisfied: 1.7 < |f1 / f| < 1.9, 1.9 < |f2 / f| < 2.1, 1.5 < |f3 / f| < 1.7, 4.5 < |f4 / f| < 4.7, 1.0 < |f5 / f| < 1.3, 6.1 < |f6 / f| < 6.3; through the mutual combination of different lenses and the reasonable distribution of the optical power, the resolution of the object-side telecentric imaging optical system 100 is improved.

[0056] To reduce costs, in an embodiment of the present invention, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are glass spherical lenses. On the basis of ensuring the imaging effect, while reducing various optical aberrations, the chromatic aberration of the system is effectively suppressed. At the same time, because glass lenses are not easily affected by thermal expansion and contraction, glass lenses can well resist the problem of lens thermal deformation and maintain the high precision of the lens for a long time. In addition, compared with aspherical lenses, they are easier to manufacture and have lower costs.

[0057] In an embodiment of the present invention, the overall optical length of the object-side telecentric imaging optical system 100, that is, the distance from the object side surface of the first lens 1 to the image side surface of the sixth lens 6 is TTL, and the focal length of the object-side telecentric imaging optical system 100 is f, and the following is satisfied: 11.5 < TTL / f < 12, 150 mm < TTL < 170 mm; by restricting the overall optical length of the object-side telecentric imaging optical system 100, it is helpful to better match with other detection components to ensure the coordinated operation of the entire system. And within a limited space, the defined overall optical length helps to optimize the system layout and form an object-side telecentric system.

[0058] In an embodiment of the present invention, the image space numerical aperture of the object space telecentric imaging optical system 100 is NA, and the f-number is F, and the following conditions are satisfied: NA≥0.12, 33.1≤F<33.5. When the f-number F of the object space telecentric imaging optical system 100 is within this range, the resolution and contrast performance of the lens are optimal, and the lens has a large light transmittance, making it easier to achieve a large target surface. In addition, it can be understood that the image space numerical aperture is an important parameter for describing the light collection ability of the objective lens. The larger the image space numerical aperture, the stronger the light collection ability of the objective lens, thereby enabling higher resolution and contrast. By restricting the image space numerical aperture, the resolution of the object space telecentric imaging optical system 100 is improved.

[0059] In an embodiment of the present invention, the refractive index of the first lens 1 is n1, the refractive index of the second lens 2 is n2, the refractive index of the third lens 3 is n3, the refractive index of the fourth lens 4 is n4, the refractive index of the fifth lens 5 is n5, and the refractive index of the sixth lens 6 is n6, and the following conditions are satisfied: 1.44 < n1 < 1.56, 1.44 < n2 < 1.56, 1.55 < n3 < 1.7, 1.45 < n4 < 1.6, 1.45 < n5 < 1.6, 1.5 < n6 < 1.65. By controlling the refractive index value ranges of the respective lenses, the refraction angles and paths of light can be more precisely controlled, thereby ensuring that the light converges to the correct position, improving clarity and reducing distortion, and enhancing the detection effect.

[0060] In an embodiment of the present invention, the Abbe number of the first lens 1 is v1, the Abbe number of the second lens 2 is v2, the Abbe number of the third lens 3 is v3, the Abbe number of the fourth lens 4 is v4, the Abbe number of the fifth lens 5 is v5, and the Abbe number of the sixth lens 6 is v6, and the following conditions are satisfied: 63.0 < v1 < 64.0, 63.0 < v2 < 64.0, 36.0 < v3 < 37.0, 70.0 < v4 < 71.0, 81.0 < v5 < 82.0, 40.0 < v6 < 41.0. By controlling the Abbe number value ranges of the respective lenses, the corresponding dispersion coefficients can effectively balance the refractive index differences of light rays of various wavelengths, reduce chromatic aberration, make the image edges clearer, and the color transition natural, forming a clear and distortion-free image.

[0061] It can be understood that the radius of curvature refers to the degree of curvature of the lens surface, which determines how light is focused or scattered. A smaller radius of curvature (larger curvature) generally means stronger focusing ability, while a larger radius of curvature (smaller curvature) provides a longer working distance and a larger depth of field. In a position alignment device, selecting an appropriate radius of curvature is crucial for achieving precise alignment. During the lithography process, the objective lens needs to be precisely focused on the wafer surface to ensure that the pattern can be accurately transferred onto the photoresist. If the range of the radius of curvature is too large or too small, it may lead to inaccurate focusing, thereby affecting the quality and yield of the final product. For example, if the radius of curvature is too small, it may increase spherical aberration; if the radius of curvature is too large, the required high resolution may not be achieved. Therefore, in an embodiment of the present invention, the radius of curvature of the object side of the first lens 1 is R2, the radius of curvature of the image side is R3, the radius of curvature of the object side of the second lens 2 is R4, the radius of curvature of the image side is R5, the radius of curvature of the object side of the third lens 3 is R6, the radius of curvature of the image side is R7, the radius of curvature of the object side of the fourth lens 4 is R9, the radius of curvature of the image side is R10, the radius of curvature of the object side of the fifth lens 5 is R11, the radius of curvature of the image side is R12, the radius of curvature of the object side of the sixth lens 6 is R13, the radius of curvature of the image side is R14, and the following conditions are satisfied: 110mm < R2 < 130mm, -25mm < R3 < -10mm, 15mm < R4 < 40mm, -45mm < R5 < -28mm, -30mm < R6 < -15mm, 45mm < R7 < 65mm, 35mm < R9 < 55mm, -145mm < R10 < -125mm, -20mm < R11 < -8mm, 45mm < R12 < 65mm, -40mm < R13 < -25mm, -30mm < R14 < -15mm; by restricting the range of the radius of curvature, spherical aberration can be reduced, the lithography quality can be improved, and an appropriate range of the radius of curvature helps to control chromatic aberration, ensuring that light of different wavelengths is focused at the same position and thus adjusting the calibration effect.

[0062] In addition, it can be understood that if the lens thickness range is inappropriate, it may lead to inaccurate focusing, thus affecting the quality and yield of the final product. For example, if the lens is too thick, chromatic aberration may increase; if the lens is too thin, the required high resolution may not be achieved. Therefore, in an embodiment of the present invention, the thickness of the first lens 1 is G1, the thickness of the second lens 2 is G2, the thickness of the third lens 3 is G3, the thickness of the fourth lens 4 is G4, the thickness of the fifth lens 5 is G5, and the thickness of the sixth lens 6 is G6, and the following conditions are satisfied: 2mm < G1 < 5mm, 2mm < G2 < 5mm, 0.8mm < G3 < 3mm, 1mm < G4 < 3mm, 1mm < G5 < 3mm, 2mm < G6 < 4mm; by restricting the thickness of each lens, it can better match other position alignment device components (such as the mask stage, wafer stage, etc.), ensuring the coordinated operation of the entire system.

[0063] Table 1

[0064]

[0065]

[0066] Specifically, in this embodiment, Figure 2 The MTF curve graph of the example at 50 lp / mm, Figure 3 is the TFM curve graph of the example at 40 lp / mm, Figure 4 is the spot diagram of the example, Figure 5 is the schematic diagram of field curvature / distortion of the example, Figure 6 is the uniformity simulation graph of the example. It can be seen from Figure 2-6 that the fixed-focus lens provided in this embodiment has good imaging ability.

[0067] The present invention also proposes a position alignment device. The security lens includes an object-side telecentric imaging optical system. The specific structure of the object-side telecentric imaging optical system refers to the above embodiment. Since this position alignment device adopts all the technical solutions of the above all embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0068] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. An object-side telecentric imaging optical system, characterized in that: include: An imaging system, wherein the object-side telecentric imaging optical system has an object side and an image side that are arranged opposite to each other along an optical axis direction, and the object-side telecentric imaging optical system is composed of a first lens, a second lens, a third lens, a beam splitter prism, a fourth lens, a fifth lens, and a sixth lens that are sequentially arranged from the object side to the image side; An illumination system, comprising a light source, the light source being arranged corresponding to the beam splitter prism, for emitting an illumination light beam, and illuminating the imaging system after being reflected by the beam splitter prism; Wherein, the first lens has positive optical power, the object side surface is convex, and the image side surface is convex; The second lens has positive power, an object side surface is convex, and an image side surface is convex; The third lens has negative optical power, the object side surface is concave, and the image side surface is concave; The fourth lens has positive refractive power, an object side surface is convex, and an image side surface is convex; The fifth lens has positive refractive power, the object side surface is concave, and the image side surface is concave; The sixth lens has positive refractive power, an object-side surface is concave, and an image-side surface is convex.

2. The object-side telecentric imaging optical system according to claim 1, characterized in that: The focal length of the object-side telecentric imaging optical system 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, and the following relationships are satisfied: 1.7<|f1 / f|<1.9, 1.9<|f2 / f|<2.1, 1.5<|f3 / f|<1.7, 4.5<|f4 / f|<4.7, 1.0<|f5 / f|<1.3, 6.1<|f6 / f|<6.

3.

3. The object-side telecentric imaging optical system according to claim 1, wherein: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses.

4. The object-side telecentric imaging optical system according to claim 1, wherein: The focal length of the object telecentric imaging optical system is f, the total optical length of the object telecentric imaging optical system is TTL, and the following conditions are met: 11.5 <TTL / f<12,150mm<TTL<170mm。 5. The object-side telecentric imaging optical system according to claim 1, wherein: The image-side numerical aperture of the object-side telecentric imaging optical system is NA, the aperture value is F, and the following conditions are met: NA≥0.12,33.1≤F<33.

5.

6. The object-side telecentric imaging optical system according to claim 1, wherein: The refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, and the refractive index of the sixth lens is n6, and the following conditions are met: 1.44 <n1<1.56,1.44<n2<1.56,1.55<n3<1.7,1.45<n4<1.6,1.45<n5<1.6,1.5<n6<1.65。 7. The object-side telecentric imaging optical system according to claim 1, wherein: The Abbe number of the first lens is v1, the Abbe number of the second lens is v2, the Abbe number of the third lens is v3, the Abbe number of the fourth lens is v4, the Abbe number of the fifth lens is v5, and the Abbe number of the sixth lens is v6, and the following conditions are met: 63.0 <v1<64.0,63.0<v2<64.0,36.0<v3<37.0,70.0<v4<71.0,81.0<v5<82.0,40.0<v6<41.0。 8. The object-side telecentric imaging optical system according to claim 1, wherein: The thickness of the first lens is G1, the thickness of the second lens is G2, the thickness of the third lens is G3, the thickness of the fourth lens is G4, the thickness of the fifth lens is G5, and the thickness of the sixth lens is G6, and the following conditions are met: 2mm <G1<5mm,2mm<G2<5mm,0.8mm<G3<3mm,1mm<G4<3mm,1mm<G5<3mm,2mm<G6<4mm。 9. The object-side telecentric imaging optical system according to claim 1, wherein: The object side surface of the first lens has a curvature radius of R2, and the image side surface has a curvature radius of R3. The object side surface of the second lens has a curvature radius of R4, and the image side surface has a curvature radius of R5. The object side surface of the third lens has a curvature radius of R6, and the image side surface has a curvature radius of R7. The object side surface of the fourth lens has a curvature radius of R9, and the image side surface has a curvature radius of R10. The object side surface of the fifth lens has a curvature radius of R11, and the image side surface has a curvature radius of R12. The object side surface of the sixth lens has a curvature radius of R13, and the image side surface has a curvature radius of R14, and the following conditions are satisfied: 110mm <R2<130mm,-25mm<R3<-10mm,15mm<R4<40mm,-45mm<R5<-28mm,-30mm<R6<-15mm,45mm<R7<65mm,35mm<R9<55mm,-145mm<R10<-125mm,-20mm<R11<-8mm,45mm<R12<65mm,-40mm<R13<-25mm,-30mm<R14<-15mm。 10. A position alignment device, characterized in that: The invention comprises the object-side telecentric imaging optical system as described in any one of claims 1 to 9.

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