Double telecentric lens, optical system and semiconductor device

Abstract

The invention discloses a double telecentric lens, an optical system and semiconductor equipment, and belongs to the technical field of optical equipment. The double telecentric lens provided by the invention comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged along an optical axis direction. The first lens group is sequentially composed of a first prism, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. And the second lens group consists of a seventh lens, an eighth lens, a ninth prism and a tenth lens in sequence. And the third lens group consists of an eleventh lens, a twelfth prism and a thirteenth lens in sequence. And the fourth lens group consists of a fourteenth lens and a fifteenth parallel plate in sequence. In the scheme, the double telecentric lens adopts an optical architecture in which the front lens group and the rear lens group cooperate, and the front lens group serves as a short-focus convergence unit to primarily converge object light and correct basic chromatic aberration; and the rear lens group is used as a long-focus imaging unit to balance aberration and realize high magnification and a flat image surface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical equipment, in particular to a dual-telecentric lens, an optical system and a semiconductor device. BACKGROUND

[0002] With the continuous miniaturization of integrated circuit technology nodes and the continuous improvement of process complexity, the resolution, imaging magnification and field uniformity of optical detection lenses for semiconductor manufacturing have almost reached the limit. However, the existing technical solutions have obvious limitations: mainstream products either cannot meet the high-precision magnification observation demand of sub-micron features in magnification, or sacrifice edge resolution and image plane flatness while achieving higher magnification. More prominently, such lenses generally lack systematic stray light suppression design, resulting in decreased imaging contrast and edge sharpness, making it difficult to obtain stable and reliable detection images in strong reflection or high contrast scenes.

[0003] Therefore, there is an urgent need for an optical lens that can achieve a system-level balance between high magnification, high resolution, excellent image plane uniformity and excellent stray light suppression capability to support quality control and yield management of advanced semiconductor manufacturing. SUMMARY

[0004] Embodiments of the present application provide a dual-telecentric lens, an optical system and a semiconductor device. The dual-telecentric lens adopts a cooperative optical architecture of front and rear lens groups, wherein the front lens group serves as a short-focus converging unit to preliminarily converge paraxial rays and correct basic chromatic aberration; the rear lens group serves as a long-focus imaging unit to balance aberration and achieve high magnification and flat image plane, finally forming a dual-telecentric lens with high magnification, high resolution and compact structure, which can meet the application requirements of high-precision imaging and measurement scenes.

[0005] To achieve the above-mentioned purpose, according to a first aspect of the present application, a dual-telecentric lens is provided, which comprises: a front lens group, an aperture stop and a rear lens group arranged in sequence along an optical axis direction; The front lens group is composed of a first lens group with positive focal power; The rear lens group is composed of a second lens group with positive focal power, a third lens group with negative focal power and a fourth lens group with positive focal power; The focal length f G1 of the front lens group and the focal length f G2 of the rear lens group satisfy the relationship: 0.014 < f G1 / f G2 < 0.034; The optical total length TTL of the dual-telecentric lens and the focal length f of the dual-telecentric lens satisfy the relationship: 0.42 < TTL / f < 1.65.

[0006] According to a second aspect of the present application, an optical system is provided, comprising: an illumination module configured to emit an illumination beam to illuminate an object to be measured; an optical imaging module having the dual-telecentric lens according to any one of the preceding technical solutions, configured to receive a light beam from the object to be measured; a photosensitive module disposed at an image plane of the optical imaging module, configured to receive an imaging light beam and convert a light signal into an electrical signal for imaging; wherein the optical imaging module further comprises an extinction unit configured to absorb or block non-imaging light.

[0007] According to a third aspect of the present application, a semiconductor device is provided, comprising: the dual-telecentric lens according to any one of the preceding technical solutions, or the optical system according to any one of the preceding technical solutions.

[0008] In the dual-telecentric lens of the embodiments of the present application, the optical architecture of the front and rear lens groups is adopted. The front lens group acts as a short-focus converging unit, which preliminarily converges light rays and corrects basic chromatic aberration. The rear lens group acts as a long-focus imaging unit, which balances aberration and realizes high magnification and flat image plane. Specifically, the first lens group has positive refractive power, acts as a main converging group on the object side, and bears a considerable part of the total refractive power, which is the core of the preliminary convergence of light rays. The second lens group has positive refractive power, acts as a relay converging group, and fine-tunes the light rays converged by the first lens group. The third lens group has negative refractive power, acts as an aberration balancing and magnification realizing group, and diverges light rays to effectively balance the positive field curvature, spherical aberration and coma produced by the front positive refractive power group (the first lens group and the second lens group), so as to ensure the imaging quality of the lens in the full field of view. At the same time, through the reasonable configuration of the refractive power and air gap, etc., the high magnification of the system is realized while the total length of the lens is effectively compressed. The fourth lens group g4 has positive refractive power, acts as an imaging and flat field group on the image side, converges light rays to the image plane and ensures that the main light rays on the image side are parallel to the optical axis, corrects residual field curvature and residual distortion, and realizes the goal of flat image plane. Finally, a dual-telecentric lens with high magnification, high resolution and compact structure is formed, which can meet the application requirements of high-precision imaging and measurement scenes.

[0009] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0011] For a more complete understanding of the present application and the advantages thereof, reference is now made to the following descriptions taken in connection with the accompanying drawings in which like numbers represent like parts.

[0012] Figure 1 is a structural schematic view of a double telecentric lens in an embodiment of the present application; Figure 2 is a field curvature graph of astigmatism of a double telecentric lens in an embodiment of the present application; Figure 3 is a distortion characteristic graph of a double telecentric lens in an embodiment of the present application; Figure 4 is a diffraction modulation transfer function curve graph of a double telecentric lens in an embodiment of the present application; Figure 5 is a point spread function graph of a double telecentric lens in an embodiment of the present application; Figure 6 is a structural schematic view of another double telecentric lens in an embodiment of the present application; Figure 7 is a field curvature graph of astigmatism of another double telecentric lens in an embodiment of the present application; Figure 8 is a distortion characteristic graph of another double telecentric lens in an embodiment of the present application; Figure 9 is a diffraction modulation transfer function curve graph of another double telecentric lens in an embodiment of the present application; Figure 10 is a point spread function graph of another double telecentric lens in an embodiment of the present application; Figure 11 is a structural schematic view of an optical system in an embodiment of the present application; Figure 12 is a structural schematic view of an extinction unit in an optical system in an embodiment of the present application; Figure 13 is a structural schematic view of an extinction unit in an optical system in an embodiment of the present application.

[0013] Explanation of reference numerals: 1 - double telecentric lens; G1 - front lens group; g1 - first lens group; L1 - first prism; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - sixth lens; S1 - aperture stop; G2 - rear lens group; g2 - second lens group; L7 - seventh lens; L8 - eighth lens; L9 - ninth prism; L10 - tenth lens; g3 - third lens group; L11 - eleventh lens; L12 - twelfth prism; L13 - thirteenth lens; g4 - fourth lens group; L14 - fourteenth lens; L15 - fifteenth parallel flat; C1 - first cemented lens; C2 - second cemented lens; C3 - third cemented lens; 100 - optical system; 10 - illumination module; 20 - optical imaging module; 30 - light sensing module; 2 - light extinction unit; 21 - lens barrel; 22 - light extinction diaphragm; 211 - inner wall of lens barrel; 212 - threaded structure; 221 - mounting portion; 222 - shielding portion; 223 - front surface; 224 - rear surface. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0015] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0016] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0017] The present application provides a double telecentric lens, an optical system and a semiconductor device, which will be described in detail below. It should be noted that the description order of the following embodiments is not limited as the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0018] Please refer to Figure 1The double telecentric lens of the present application comprises, in order along the optical axis direction, a front lens group G1, an aperture stop S1 and a rear lens group G2. The front lens group G1 is composed of a first lens group g1 with positive focal power, and the rear lens group G2 is composed of a second lens group g2 with positive focal power, a third lens group g3 with negative focal power and a fourth lens group g4 with positive focal power. The first lens group g1 is composed of, in order along the optical axis direction, a first prism L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6. The second lens group g2 is composed of, in order along the optical axis direction, a seventh lens L7, an eighth lens L8, a ninth prism L9 and a tenth lens L10. The third lens group g3 is composed of, in order along the optical axis direction, an eleventh lens L11, a twelfth prism L12 and a thirteenth lens L13. The fourth lens group g4 is composed of, in order along the optical axis direction, a fourteenth lens L14 and a fifteenth parallel flat plate L15. The focal length f G1 of the front lens group G1 and the focal length f G2 of the rear lens group G2 satisfy the relationship: 0.014 < f G1 / f G2 < 0.034. The optical total length TTL of the double telecentric lens and the focal length f of the double telecentric lens satisfy the relationship: 0.42 < TTL / f < 1.65.

[0019] In the technical scheme, the double telecentric lens is divided into a front lens group G1 and a rear lens group G2 with the aperture stop S1 as the boundary. The light path from the object plane to the aperture stop S1 is the front lens group G1, the light path from the aperture stop S1 to the image plane is the rear lens group G2, and the aperture stop S1 is arranged at the image-side focal plane of the front lens group G1 and also at the object-side focal plane of the rear lens group G2, so as to ensure object-side telecentricity and image-side telecentricity. The focal length f G1 of the front lens group G1 and the focal length f G2 of the rear lens group G2 satisfy the relationship: 0.014 < f G1 / f G2 < 0.034. It can be seen that the focal length f G2 of the rear lens group is much larger than the focal length f G1 of the front lens group (the focal length f G1 of the front lens group is much smaller than the focal length f G2 of the rear lens group), which can realize high magnification imaging. In the present application, based on the focal length ratio of the above-mentioned front and rear lens groups, the front lens group G1 serves as a short-focus converging unit, which preliminarily converges object-side light rays and corrects basic chromatic aberration and other aberrations; and the rear lens group G2 serves as a long-focus imaging unit, which balances aberrations and realizes high magnification and flat image plane.

[0020] The front lens group G1 is composed of a first lens group g1. The first lens group g1 has positive refractive power, as a main converging group on the object side, undertakes a considerable part of the total focal power, and is the core of the initial convergence of light rays. The rear lens group G2 is composed of a second lens group g2, a third lens group g3 and a fourth lens group g4 in sequence from the object side to the image side. The second lens group g2 has positive refractive power, as a relay converging group, receives and finely controls the light rays converged by the first lens group g1, and cooperates with the first lens group g1 to correct the off-axis aberrations related to the pupil, such as astigmatism, coma and distortion. The third lens group g3 has negative refractive power, as an aberration balancing and magnification realizing group, diverges light rays to effectively balance the positive field curvature and other aberrations generated by the front positive refractive power group (the first lens group g1 and the second lens group g2), and ensures the imaging quality of the lens in the full field of view; at the same time, through the reasonable configuration of refractive power and air gap, etc., the high magnification of the system is realized while the total length of the lens is effectively compressed.

[0021] The optical total length of the dual-telecentric lens is TTL, and the total focal length of the dual-telecentric lens is f, both of which satisfy the following relationship: 0.42 < TTL / f < 1.65. Through the reasonable refractive power distribution of the above-mentioned front and rear lens groups, the ratio of the optical total length TTL of the dual-telecentric lens to the total focal length f thereof can be kept within a lower range under the premise of guaranteeing high magnification and dual-telecentric characteristics, effectively avoiding excessive redundancy of the lens volume, and realizing the design goal of high magnification and small size of the lens.

[0022] In some embodiments, the focal length f g1 of the first lens group g1 and the total focal length f of the dual-telecentric lens satisfy the following relationship: 0.04 < |f g1 / f| < 0.17. When 0.04 < |f g1 / f| < 0.17, on the one hand, the strong positive refractive power in front provides sufficient aberration correction space for the rear lens group, so that the rear lens group can focus more on aberration balancing rather than refractive power contribution, improving the efficiency and effect of aberration correction; on the other hand, the light rays are strongly converged in the front part (the first lens group g1) of the lens, so that the clear aperture of the second lens group g2 and the subsequent lens groups can be reduced, thereby reducing the total material cost and overall weight of the lens.

[0023] The focal length f g2 of the second lens group g2 and the total focal length f of the dual-telecentric lens satisfy the following relationship: 0.01 < |f g2 / f| < 0.08. When 0.01 < |f g2When / f|<0.08, on the one hand, it ensures that the second lens group g2 and the first lens group g1 form a high-performance composite positive group. The two work together to ensure that aberrations such as spherical aberration and coma are effectively corrected before the light enters the third lens group g3 with negative optical power, reducing the burden on subsequent lens groups. On the other hand, the second lens group g2 can smoothly receive and transmit the light beam from the first lens group g1, avoiding aberration deterioration caused by drastic changes in optical power between the first lens group g1 and the third lens group g3, and ensuring the stability of the optical path transmission.

[0024] The focal length f of the third lens group g3 g3 The focal length f of a double telecentric lens satisfies the following relationship: 0.002 < |f g3 / f|<0.016. At 0.002<|f g3 When / f|<0.016, on the one hand, it ensures that the third lens group g3 has sufficient but not excessive negative optical power, which can accurately cancel the positive field curvature and other aberrations generated by the front positive optical power group (the first lens group g1 and the second lens group g2), which is conducive to achieving high resolution and a flat image plane; on the other hand, the third lens group g3 pushes the image-side principal point of the lens to the image-side side, which significantly compresses the total optical length TTL. This greatly reduces the physical volume of the lens while ensuring high magnification, and adapts to the demanding installation space requirements of semiconductor devices.

[0025] The focal length f of the fourth lens group g4 g4 The focal length f of a double telecentric lens satisfies the following relationship: 0.14 < |f g4 / f|<0.7. In 0.14<|f g4 When / f|<0.7, on the one hand, it ensures that the fourth lens group g4 is at a suitable optical power, so that it can accurately control the angle of the principal ray arriving at the image plane and ensure excellent image-side telecentricity; on the other hand, the fourth lens group g4 performs final processing on the imaging beam balanced by the third lens group g3, effectively correcting residual astigmatism, field curvature and distortion and other aberrations, ensuring consistent and clear imaging quality across the entire image plane.

[0026] Preferably, the focal length f of the first lens group g1 g1 The focal length f of the second lens group g2 is 19.2 ± 5% mm. g2 The focal length f of the third lens group g3 is 9.0±5% mm. g3 The focal length f of the fourth lens group g4 is 1.6±5%mm. g4 The diameter is 67.5~85.6mm.

[0027] Preferably, the lenses in the front lens group G1 and the rear lens group G2 are all spherical lenses. The first prism L1, the ninth prism L9 and the twelfth prism L12 have no optical power, and both the object side and the image side are flat. The second lens L2, the fourth lens L4, the seventh lens L7 and the tenth lens L10 have positive optical power, and are double convex lenses with convex object side and convex image side. The third lens L3 has negative optical power, and is a meniscus negative lens with convex object side and concave image side. The fifth lens L5 has positive optical power, and is a meniscus positive lens with concave object side and convex image side. The sixth lens L6 has negative optical power, and is a meniscus negative lens with concave object side and convex image side. The eighth lens L8, the eleventh lens L11 and the thirteenth lens L13 have negative optical power, and are double concave lenses with concave object side and concave image side. The fourteenth lens L14 has positive optical power, and is a plano-convex lens with flat object side and convex image side. The fifteenth parallel flat plate L15 has no optical power, and both the object side and the image side are flat.

[0028] In the technical scheme, first, the light beam from the object side is incident to the first prism L1 in the first lens group g1 to make the first light path turn, and then enters the second lens L2 to preliminarily converge the divergent light rays from the object side. The light beam then passes through the first cemented lens C1 composed of the third lens L3 and the fourth lens L4, which is used to correct chromatic aberration. Then, the light beam passes through the second cemented lens C2 composed of the fifth lens L5 and the sixth lens L6, which is used to assist in correcting chromatic aberration while compensating for spherical aberration and coma, thereby laying a good image quality foundation for the subsequent lens group.

[0029] Then, the light beam enters the third cemented lens C3 composed of the seventh lens L7 and the eighth lens L8 in the second lens group g2 to finely compensate for the residual aberration of the aforementioned lens group. Then, the light beam is incident to the ninth prism L9 to make the second light path turn and enters the tenth lens L10 to shape the wavefront of the light beam, thereby ensuring that the light beam is shot to the third lens group g3 in the best form.

[0030] Then, the light beam enters the eleventh lens L11 in the third lens group g3 to apply strong divergence to the converging light beam, effectively offsetting the positive field curvature accumulated by the front positive power group and balancing the spherical aberration and coma. Then, the light beam is incident to the twelfth prism L12 to make the third light path turn, and passes through the thirteenth lens L13 to further apply divergence to the converging light beam, which cooperates with the eleventh lens L11 to push the image side of the image side principal point of the lens, effectively compressing the rear working distance and the total length of the lens.

[0031] Finally, the light beam enters the fourteenth lens L14 in the fourth lens group g4 to be re-collimated and converged, so that the chief ray is incident to the image plane at an angle parallel to the optical axis and corrects residual field curvature and other aberrations. Finally, the light beam passes through the fifteenth parallel flat L15 as a protective glass to guide the corrected light beam to the image plane to form a final image with high magnification, high resolution and double telecentricity.

[0032] It can be understood that the first prism L1, the ninth prism L9 and the twelfth prism L12 are preferably split prisms or reflective prisms.

[0033] In some embodiments, the third lens L3 and the fourth lens L4 are cemented to each other to form a first cemented lens C1. The focal length f C1 of the first cemented lens C1 and the total focal length f of the double telecentric lens satisfy the relationship: 0.06<|f C1 / f|<0.28. The focal length f3 of the third lens L3 and the focal length f4 of the fourth lens L4 satisfy the relationship: 1.4<f3 / f4<1.8.

[0034] The fifth lens L5 and the sixth lens L6 are cemented to each other to form a second cemented lens C2. The focal length f C2 of the second cemented lens C2 and the total focal length f of the double telecentric lens satisfy the relationship: 0.05<|f C2 / f|<0.22. The focal length f5 of the fifth lens L5 and the focal length f6 of the sixth lens L6 satisfy the relationship: 1.3<f5 / f6<1.7.

[0035] The seventh lens L7 and the eighth lens L8 are cemented to each other to form a third cemented lens C3. The focal length f C3 of the third cemented lens C3 and the total focal length f of the double telecentric lens satisfy the relationship: 0.2<|f C3 / f|<0.75. The focal length f7 of the seventh lens L7 and the focal length f8 of the eighth lens L8 satisfy the relationship: 1.2<f7 / f8<1.6.

[0036] In this technical solution, the first cemented lens C1 serves as a strong power group, mainly used to correct chromatic aberration of the system, laying the foundation for high resolution of the entire lens. The second cemented lens C2 also has strong power, which cooperates with the first cemented lens C1 to further assist in correcting chromatic aberration, and corrects spherical aberration and coma to ensure uniform and sharp imaging quality from the center to the medium field area. The third cemented lens C3 as a weak power group close to the image plane mainly corrects the residual aberrations of the first cemented lens C1 and the second cemented lens C2 for fine compensation. The three work together to realize the key of full-field high-definition imaging.

[0037] In some embodiments, the sagittal height SAG34 of the first cemented surface of the first cemented lens C1 along the optical axis direction and the total center thickness CT34 of the first cemented lens C1 on the optical axis satisfy the relationship: 0.18 < SAG34 / CT34 < 0.22. The sagittal height SAG56 of the second cemented surface of the second cemented lens C2 along the optical axis direction and the total center thickness CT56 of the second cemented lens C2 on the optical axis satisfy the relationship: 0.21 < SAG56 / CT56 < 0.25. The sagittal height SAG78 of the third cemented surface of the third cemented lens C3 along the optical axis direction and the total center thickness CT78 of the third cemented lens C3 on the optical axis satisfy the relationship: 0.02 < SAG78 / CT78 < 0.04.

[0038] In some embodiments, in the first cemented lens C1: the Abbe number Vd3 of the third lens L3 and the Abbe number Vd4 of the fourth lens L4 satisfy the relationship: Vd3 < Vd4. The refractive index Nd3 of the third lens L3 and the refractive index Nd4 of the fourth lens L4 satisfy the relationship: Nd3 > Nd4. In the second cemented lens C2: the Abbe number Vd5 of the fifth lens L5 and the Abbe number Vd6 of the sixth lens L6 satisfy the relationship: Vd5 > Vd6. The refractive index Nd5 of the fifth lens L5 and the refractive index Nd6 of the sixth lens L6 satisfy the relationship: Nd5 < Nd6. In the third cemented lens C3: the Abbe number Vd7 of the seventh lens L7 and the Abbe number Vd8 of the eighth lens L8 satisfy the relationship: Vd7 > Vd8. The refractive index Nd7 of the seventh lens L7 and the refractive index Nd8 of the eighth lens L8 satisfy the relationship: Nd7 < Nd8.

[0039] Preferably, the refractive index of the third lens L3 is 1.83 ± 5%, and the Abbe number is 37.2 ± 5%; the refractive index of the fourth lens L4 is 1.50 ± 5%, and the Abbe number is 81.6 ± 5%. The refractive index of the fifth lens L5 is 1.74 ± 5%, and the Abbe number is 45.0 ± 5%; the refractive index of the sixth lens L6 is 1.80 ± 5%, and the Abbe number is 25.5 ± 5%. The refractive index of the seventh lens L7 is 1.50 ± 5%, and the Abbe number is 81.6 ± 5%; the refractive index of the eighth lens L8 is 1.83 ± 5%, and the Abbe number is 37.2 ± 5%.

[0040] Preferably, the thickness of the first cemented lens C1 is 5.6 ± 0.5 mm, the thickness of the second cemented lens C2 is 4.7 ± 0.5 mm, and the thickness of the third cemented lens C3 is 5.0 ± 0.5 mm.

[0041] Preferably, the focal length of the first cemented lens C1 is 32.0 ± 5% mm, the focal length of the second cemented lens C2 is 24.8 ± 5% mm, and the focal length of the third cemented lens C3 is 89.5 ± 5% mm.

[0042] In some embodiments, in the third lens group g3, the focal length f11 of the eleventh lens L11 and the focal length f13 of the thirteenth lens L13 satisfy the relationship: 0.03 < (f11 + f13) / f < 0.19, where f is the total focal length of the double telecentric lens. The total optical length TTL of the double telecentric lens and the focal length f g3 of the third lens group g3 satisfy the relationship: 111 < TTL / f g3 < 118. The air gap of the third lens group g3 and the fourth lens group g4 is 58.7 ± 0.5 mm.

[0043] In this technical solution, the ratio of the total optical length TTL of the double telecentric lens and the focal length f g3 of the third lens group g3 is within the range of 111 < TTL / f g3 < 118. By adjusting the value of the focal length f g3 of the third lens group g3, if the focal length f g3 of the third lens group g3 is too short (the negative focal power is too strong), although the total length can be significantly compressed, the third lens group g3 itself will generate high-order astigmatism and coma that is difficult to compensate, and the aberration balance of the system will be disturbed too much. Conversely, if the focal length f g3 of the third lens group g3 is too long (the negative focal power is too weak), the positive field curvature generated by the front positive focal power group cannot be effectively offset, and the ability to compress the total length of the lens is also lost. Therefore, the value of the focal length f g3 of the third lens group g3 is optimized to configure the third lens group g3 with appropriate negative focal power, thereby simultaneously achieving excellent aberration correction and structural miniaturization. In addition, the air gap between the third lens group g3 and the fourth lens group g4 is set to 58.7 ± 0.5 mm, which provides the necessary evolution distance for the light beam after being diverged by the third lens group g3, so that it can enter the fourth lens group g4 with the best beam aperture and incident angle, ensuring the efficiency and imaging quality of the subsequent converging process.

[0044] In some embodiments, the Abbe number Vd11 of the eleventh lens L11 and the Abbe number Vd13 of the thirteenth lens L13 satisfy the relationship: Vd11 = Vd13; the refractive index Nd11 of the eleventh lens L11 and the refractive index Nd13 of the thirteenth lens L13 satisfy the relationship: Nd11 = Nd13. The Abbe number Vd13 of the thirteenth lens L13 and the Abbe number Vd12 of the twelfth prism L12 satisfy the relationship: Vd13 < Vd12; the refractive index Nd13 of the thirteenth lens L13 and the refractive index Nd12 of the twelfth prism L12 satisfy the relationship: Nd13 > Nd12.

[0045] In the technical solution, the eleventh lens L11 and the thirteenth lens L13 are both made of high refractive index and low dispersion material, and the optical power of both is negative. The same material characteristics make the dispersion behavior highly consistent, and the axial chromatic aberration and magnification chromatic aberration generated in the optical path as a whole can form a synergistic inhibition effect, controlling the contribution of the two types of chromatic aberration within the error threshold allowed by the system, and avoiding the introduction of uncontrollable chromatic aberration variables in the key link of aberration balance. The twelfth prism L12 is arranged between the eleventh lens L11 and the thirteenth lens L13. Although it has no optical power, the physical thickness will introduce positive dispersion. Therefore, the material characteristics and the position of L13 are compensated to realize accurate matching and offset of the dispersion value, and further improve the overall imaging quality of the system.

[0046] Preferably, the refractive index of the eleventh lens L11 and the thirteenth lens L13 is 1.88±5%, and the Abbe number is 40.9±5%. The refractive index of the twelfth prism L12 is 1.51±5%, and the Abbe number is 64.2±5%.

[0047] Preferably, the thickness of the eleventh lens L11 is 2.0±0.5mm, the thickness of the twelfth prism L12 is 8.0mm, and the thickness of the thirteenth lens L13 is 2.0~5.0mm.

[0048] Preferably, the air gap between the eleventh lens L11 and the twelfth prism L12 is 6.5±0.5mm; the air gap between the twelfth prism L12 and the thirteenth lens L13 is 1.9±0.5mm.

[0049] In some embodiments, in the fourth lens group g4, the focal length f14 of the fourteenth lens L14 and the focal length f of the double telecentric lens satisfy the relationship: 0.15

[0050] In the technical solution, when the focal length f14 of the fourteenth lens L14 and the focal length f of the double telecentric lens satisfy the relationship: 0.15

[0051] In some embodiments, the Abbe number Vd14 of the fourteenth lens L14 and the Abbe number Vd15 of the fifteenth parallel plate L15 satisfy the relationship: Vd14 < Vd15. The refractive index Nd14 of the fourteenth lens L14 and the refractive index Nd15 of the fifteenth parallel plate L15 satisfy the relationship: Nd14 > Nd15.

[0052] Preferably, the refractive index of the fourteenth lens L14 is 1.83 ± 5%, and the Abbe number is 37.2 ± 5%. The refractive index of the fifteenth parallel plate L15 is 1.51 ± 5%, and the Abbe number is 64.2 ± 5%.

[0053] Preferably, the thickness of the fourteenth lens L14 is 2.9 ± 0.5 mm, and the thickness of the fifteenth parallel plate L15 is 2.0 mm.

[0054] Preferably, the air gap of the fourteenth lens L14 and the fifteenth parallel plate L15 is 0.5 ± 0.3 mm.

[0055] In addition, in the technical solution of the present application, preferably, the refractive index of the first prism L1 is 1.51 ± 5%, and the Abbe number is 64.2 ± 5%. The refractive index of the second lens L2 is 1.80 ± 5%, and the Abbe number is 25.5 ± 5%. The refractive index of the ninth prism L9 is 1.51 ± 5%, and the Abbe number is 64.2 ± 5%. The refractive index of the tenth lens L10 is 1.80 ± 5%, and the Abbe number is 25.5 ± 5%.

[0056] Preferably, the thickness of the first prism L1 is 12.0 mm, and the thickness of the second lens L2 is 2.8 ± 0.5 mm; the thickness of the ninth prism L9 is 8.0 mm, and the thickness of the tenth lens L10 is 2.5 ± 0.5 mm.

[0057] Preferably, the air gap of the first prism L1 and the second lens L2 is 0.5 ± 0.3 mm, the air gap of the second lens L2 and the third lens L3 is 0.5 ± 0.3 mm, the air gap of the fourth lens L4 and the fifth lens L5 is 0.5 ± 0.3 mm, the air gap of the sixth lens L6 and the seventh lens L7 is 1.5 ± 0.5 mm, the air gap of the eighth lens L8 and the ninth prism L9 is 2.5 ± 0.5 mm, the air gap of the ninth prism L9 and the tenth lens L10 is 2.0 ± 0.5 mm, and the air gap of the tenth lens L10 and the eleventh lens L11 is 1.0 ± 0.5 mm.

[0058] In some embodiments, the entrance pupil diameter D of the dual-telecentric lens and the total focal length f of the dual-telecentric lens satisfy the relationship: 0.02 ≤ D / 2f ≤ 0.06, which can balance the light collection ability, the theoretical diffraction limit resolution, and the aberration correction difficulty.

[0059] In some embodiments, the total focal length f of the double telecentric lens and the optical total length TTL of the double telecentric lens, half of the diagonal length of the effective pixel area of the photosensitive module ImgH satisfy the relationship: 0.31≤f / (TTL×ImgH)≤1.13, which can minimize the total length of the optical system under the premise of ensuring high magnification, that is, the unification of high performance and high compactness is realized.

[0060] According to the foregoing description, the following will be described in detail in combination with more specific embodiments and drawings.

[0061] Embodiment One

[0062] The following Table 1 details the specific design parameters of each lens assembly of the double telecentric lens in this embodiment, including the optical property indicators and geometric structure parameters of each element.

[0063]

Table 1

[0064] In this embodiment, as shown in Figure 1 , the first prism L1 is a light splitting prism, the second lens L2 is a double convex lens, the third lens L3 is a meniscus negative lens, the fourth lens L4 is a double convex lens, the fifth lens L5 is a meniscus positive lens, the sixth lens L6 is a meniscus negative lens, the seventh lens L7 is a double convex lens, the eighth lens L8 is a double concave lens, the ninth prism L9 is a light splitting prism, the tenth lens L10 is a double convex lens, the eleventh lens L11 is a double concave lens, the twelfth prism L12 is a light splitting prism, the thirteenth lens L13 is a double concave lens, the fourteenth lens L14 is a plano-convex lens, and the fifteenth parallel flat plate L15 is a parallel flat plate. Object is an object plane, S1 is a diaphragm, and Image is an image plane.

[0065] In this embodiment, the total focal length f of the double telecentric lens is 405.2 mm, the optical total length TTL is 180 mm, the focal length f G1 of the front lens group is 19.2 mm, the focal length f G2 of the rear lens group is 666 mm, and f G1 / f G2 = 0.029. The focal length f g1 of the first lens group g1 is 19.2 mm, the focal length f g2 of the second lens group g2 is 9.0 mm, the focal length f g3 of the third lens group g3 is 1.6 mm, the focal length f g4 of the fourth lens group g4 is 67.5 mm, |f g1 / f| = 0.047, |f g2 / f| = 0.022, |f g3 / f| = 0.004, |fg4 f3 / f4 = 1.69, |f C1 f3 / f4 = 1.69, |f C2 f5 / f6 = 1.5, |f C3 f7 / f8 = 1.4. SAG34 / CT34 = 0.20, SAG56 / CT56 = 0.23, SAG78 / CT78 = 0.037. (f12+f13) / f = 0.033, TTL / f g3 = 112.5. f14 / f = 0.167. D / 2f = 0.02, f / (TTL x ImgH) = 1.13.

[0066] In this embodiment, the object-side numerical aperture of the dual-telecentric lens is 0.1-0.2, the wavelength range is 400-800 nm, and the object-side field diameter is greater than 1 mm. The magnification of the dual-telecentric lens is -20x, the object-side working distance is greater than or equal to 20 mm, and the image-side working distance is greater than or equal to 25 mm. The dual-telecentric lens has object-side and image-side dual-telecentric structures: the chief rays of each field of view in the object side are approximately parallel to the optical axis and are incident on the first lens group g1, and the angle between the chief rays and the optical axis is less than or equal to 0.1°; the chief rays of each field of view in the image side are approximately parallel to the optical axis and are incident on the image plane, and the angle between the chief rays and the optical axis is less than or equal to 0.1°, ensuring the consistency of telecentricity in the full field of view.

[0067] Please refer to Figure 2 , Figure 2 for the astigmatic field curvature diagram of the dual-telecentric lens. In the diagram, the horizontal axis represents the focal point offset (unit: mm), and the positive and negative values correspond to the offset direction of the image point relative to the ideal focal plane, and the numerical value represents the offset degree; the vertical axis represents the object height (unit: mm), the dashed line T represents the meridional field curvature (T-field), and the solid line S represents the sagittal field curvature (S-field). As can be seen from the diagram, within the wavelength range of 400-800 nm, the field curvature deviation and the difference between the meridional and sagittal field curvatures (i.e. the astigmatism value) of the full field of view are all controlled within ±0.025 mm, indicating that the field curvature and astigmatism correction effect of the system is excellent, the imaging spot profile is closer to the ideal geometric shape, and the imaging clarity consistency of the full field of view is ensured.

[0068] Please refer to Figure 3 , Figure 3 for the distortion characteristic diagram of the dual-telecentric lens. As can be seen from the diagram, within the working wavelength range of 400-800 nm and the full field of view, the absolute value of the distortion of the lens is ≤0.009%, and the distortion is symmetrically distributed, indicating that the geometric deformation degree of the imaging pattern is extremely low, and the real size and shape of the object in the object side can be accurately restored, meeting the stringent requirements of high-precision measurement scenes on distortion control.

[0069] Please refer toFigure 4 , Figure 4 This is a graph showing the diffraction modulation transfer function (MTF) curves of the dual telecentric lens. The horizontal axis represents spatial frequency (unit: lp / mm (period / mm)), and the vertical axis represents the MTF value (range 0~1). The curve labeled "F1:Diff.Limit" is the system's diffraction-limited MTF curve. The other curves correspond to the MTF curves under different field-of-view angles (or object heights) and designed object distances within the 400nm~800nm ​​working band and the full field of view. As shown in the graph, all MTF curves across the entire band and field of view highly coincide with the diffraction-limited curve, indicating that the optical transfer capability of this dual telecentric lens is close to the theoretical limit, exhibiting excellent image sharpness and detail reproduction, and possessing high-resolution imaging performance.

[0070] Please see Figure 5 , Figure 5 This is a dot plot of the dual telecentric lens. The horizontal axis represents the lateral offset within the image plane (unit: μm), and the vertical axis represents the field of view position (unit: mm). This dot plot corresponds to the 400nm~800nm ​​working wavelength band, the designed object distance, and the ideal focusing state (defocusing = 0). As shown in the figure, the imaging blur spots (centroid or root-mean-square radius) at each field of view position across the entire field of view are all within the Airy disk radius range of the corresponding wavelength, and the blur spot size is uniform. This indicates that the dual telecentric lens has sufficient aberration correction, excellent imaging spot concentration, and can achieve high-fidelity, high-resolution imaging effects. It can be understood that... Figure 5 The RMS (Root Mean Square) in the equation is used to quantitatively describe the dispersion of the light spot.

[0071] Example 2

[0072] Table 2 below details the specific design parameters of each lens assembly in the dual telecentric lens of this embodiment, including the optical characteristics and geometric parameters of each element. Except for the relevant parameters in Table 2, all other parameters are the same as in Embodiment 1, therefore the overlapping parts will not be repeated.

[0073] Table 2

[0074] In this embodiment, such as Figure 6As shown, the first prism L1 is a light splitting prism, the second lens L2 is a double convex lens, the third lens L3 is a meniscus negative lens, the fourth lens L4 is a double convex lens, the fifth lens L5 is a meniscus positive lens, the sixth lens L6 is a meniscus negative lens, the seventh lens L7 is a double convex lens, the eighth lens L8 is a double concave lens, the ninth prism L9 is a light splitting prism, the tenth lens L10 is a double convex lens, the eleventh lens L11 is a double concave lens, the twelfth prism L12 is a light splitting prism, the thirteenth lens L13 is a double concave lens, the fourteenth lens L14 is a plano-convex lens, and the fifteenth parallel flat plate L15 is a parallel flat plate. Object is an object plane, S1 is a diaphragm, and Image is an image plane.

[0075] In this embodiment, the total focal length of the double telephoto lens is f = 123.4 mm, the total optical length TTL = 200 mm, the focal length of the front lens group f G1 = 19.2 mm, the focal length of the rear lens group f G2 = 996 mm, f G1 / f G2 = 0.019. The focal length of the first lens group g1 is f g1 = 19.2 mm, the focal length of the second lens group g2 is f g2 = 9.0 mm, the focal length of the third lens group g3 is f g3 = 1.6 mm, the focal length of the fourth lens group g4 is f g4 = 85.6 mm, |f g1 / f| = 0.156, |f g2 / f| = 0.064, |f g3 / f| = 0.014, |f g4 / f| = 0.694. |f C1 / f| = 0.26, f3 / f4 = 1.69, |f C2 / f| = 0.20, f5 / f6 = 1.5, |f C3 / f| = 0.73, f7 / f8 = 1.4. SAG34 / CT34 = 0.20, SAG56 / CT56 = 0.23, SAG78 / CT78 = 0.037. (f12+f13) / f = 0.188, TTL / f g3 = 117.6. f14 / f = 0.68. D / 2f = 0.06, f / (TTL x ImgH) = 0.31.

[0076] In this embodiment, the object-side numerical aperture of the dual-telecentric lens is 0.1-0.2, the wavelength range is 400-800 nm, and the object-side field diameter is greater than 1 mm. The magnification of the dual-telecentric lens is -20x, the object-side working distance is ≥20 mm, and the image-side working distance is ≥25 mm. The dual-telecentric lens has a dual-telecentric structure on the object and image sides: the chief rays of each field of view on the object side are approximately parallel to the optical axis and are incident on the first lens group g1, and the angle between the chief rays and the optical axis is less than or equal to 0.1°; the chief rays of each field point on the image side are approximately parallel to the optical axis and are incident on the image plane, and the angle between the chief rays and the optical axis is less than or equal to 0.1°, ensuring the consistency of telecentricity in the full field of view.

[0077] Please refer to Figure 7 , Figure 7 is the astigmatism field curvature diagram of the dual-telecentric lens. In the diagram, the horizontal axis represents the focal shift (unit: mm), and the positive and negative values correspond to the direction of the image point relative to the ideal focal plane. The numerical value represents the degree of deviation. The vertical axis represents the object height (unit: mm). The dashed line T represents the meridional field curvature (T-field), and the solid line S represents the sagittal field curvature (S-field). As can be seen from the diagram, within the wavelength range of 400-800 nm, the field curvature deviation and the difference between the meridional and sagittal field curvatures (i.e., the astigmatism value) of the full field of view are controlled within ±0.025 mm, indicating that the system has excellent field curvature and astigmatism correction effects, and the imaging spot profile is closer to the ideal geometric shape, ensuring the consistency of the imaging clarity of the full field of view.

[0078] Please refer to Figure 8 , Figure 8 is the distortion characteristic diagram of the dual-telecentric lens. As can be seen from the diagram, within the working wavelength range of 400-800 nm and the full field of view, the absolute value of the distortion of the lens is ≤0.016%, indicating that the geometric deformation degree of the imaging pattern is extremely low, and the real size and shape of the object on the object side can be accurately restored, meeting the stringent requirements of high-precision measurement scenarios for distortion control.

[0079] Please refer to Figure 9 , Figure 9 is the diffraction modulation transfer function (MTF) curve diagram of the dual-telecentric lens. In the diagram, the horizontal axis represents the spatial frequency (unit: lp / mm (period / mm)), and the vertical axis represents the MTF value (value range 0-1). The curve labeled "F1: Diff. Limit" is the system diffraction limit MTF curve, and the remaining multiple curves correspond to the MTF curves under different field angles (or object heights) and design object distances within the working wavelength range of 400-800 nm and the full field of view. As can be seen from the diagram, all the MTF curves within the full wavelength range and the full field of view are highly consistent with the diffraction limit curve, indicating that the optical transfer capability of the dual-telecentric lens is close to the theoretical limit, and the imaging sharpness and detail restoration capability are excellent, with high-resolution imaging performance.

[0080] Referring to Figure 10 , Figure 10 is a spot diagram of the dual-telecentric lens. The horizontal coordinate in the diagram represents the lateral offset in the image plane (unit: pm), and the vertical coordinate represents the field position (unit: mm). The spot diagram corresponds to the working waveband of 400 nm to 800 nm, the design object distance, and the ideal focusing state (defocus amount = 0). As can be seen from the diagram, the imaging diffraction spots (centroid or root mean square radius) of each field position in the full field range are within the range of the Airy disk radius corresponding to the wavelength, and the diffraction spot size is uniform, indicating that the aberration correction of the dual-telecentric lens is sufficient, the imaging spot concentration is excellent, and high-fidelity and high-resolution imaging effects can be achieved. It can be understood that Figure 10 RMS (Root Mean Square) in the formula is used to quantitatively describe the dispersion degree of the spot.

[0081] Referring to Figure 11 In the embodiments of the present application, the present application also provides an optical system 100, comprising: an illumination module 10 for emitting an illumination light beam to irradiate a to-be-measured object; an optical imaging module 20 having a dual-telecentric lens 1 as recited in any of the above technical solutions, for receiving a light beam from the to-be-measured object; and a photosensitive module 30 arranged at the image plane position of the optical imaging module, for receiving an imaging light beam and converting a light signal into an electrical signal for imaging. The optical imaging module 20 further has an extinction unit 2 for absorbing or blocking non-imaging light.

[0082] Referring to Figure 12 The extinction unit 2 is composed of a lens barrel 21 and a plurality of extinction diaphragms 22 mounted on the inner wall 211 of the lens barrel. The extinction diaphragms 22 are arranged between the third lens group g3 and the fourth lens group g4, specifically between the thirteenth lens L13 and the fourteenth lens L14, for absorbing or blocking the non-imaging light generated between the aforementioned lens groups, thereby suppressing stray light. The mounting positions of the plurality of extinction diaphragms 22 and their light apertures can be designed according to the actual stray light distribution of the system. By fine-tuning the positions of the extinction diaphragms 22 along the optical axis direction, they can be accurately set in the area between the inner walls of the lens barrel 21 where the stray light reflection is most concentrated. This can maximize the interception and absorption of the multiple-reflected stray light, change its propagation path, and thus significantly improve the stray light suppression capability of the system and improve the imaging signal-to-noise ratio.

[0083] Referring to Figure 13The light extinction diaphragm 22 comprises a mounting portion 221 and a shielding portion 222 connected to the mounting portion 221. The mounting portion 221 is fixed to the lens barrel 21 through the threaded structure 212 of the inner wall 211 of the lens barrel 21. The shielding portion 222 extends inwardly from the mounting portion 221 in a direction perpendicular to the optical axis of the dual-telecentric lens 1. By arranging the light extinction diaphragm 22, the shielding portion 222 can effectively intercept stray light propagating at a large angle. When such light is incident to the front surface 223 of the shielding portion 222 which is specially treated for light extinction, most of the energy is absorbed, and only extremely weak reflected light returns to the front lens barrel space at a similar angle. The energy is sharply attenuated in subsequent multiple reflections and cannot propagate to the image plane. At the same time, stray light incident at a small angle can bypass the edge of the current light extinction diaphragm 22 and continue to propagate along the optical axis. Residual small-angle stray light will be intercepted and absorbed again by the rear light extinction diaphragm 22, thereby forming a full-range, multi-stage suppression system covering large and small angle stray light, ensuring that stray light cannot finally reach the sensor imaging plane.

[0084] In some embodiments of the present application, the present application also provides a semiconductor device comprising the dual-telecentric lens according to any one of the technical solutions above, or the optical system according to any one of the technical solutions above. Since the dual-telecentric lens or the optical system in the semiconductor device has the same technical features as the dual-telecentric lens or the optical system described above, they can solve the same technical problems and achieve the same technical effects.

[0085] In the description of the present specification, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0086] The above describes only the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims. In addition, the specific examples are applied in the present specification to describe the principles and implementation modes of the present application. The above description of the embodiments is only used to help understand the method of the present application and its core idea, and the content of the present specification should not be understood as a limitation of the present application.

Claims

1. A double telecentric lens, characterized in that, include: The front lens group, aperture stop, and rear lens group are arranged sequentially along the optical axis. The front lens group includes a first lens group with positive optical power; The rear lens group includes a second lens group with positive optical power, a third lens group with negative optical power, and a fourth lens group with positive optical power. The focal length f of the front lens group G1 The focal length f of the rear lens group G2 The relation 0.014 < f is satisfied. G1 / f G2 <0.034; The total optical length TTL of the dual telecentric lens and the focal length f of the dual telecentric lens satisfy the following relationship: 0.42 < TTL / f < 1.

65.

2. The double telecentric lens according to claim 1, characterized in that, The focal length f of the first lens group g1 The focal length f of the aforementioned telecentric lens satisfies the following relationship: 0.04 < |f g1 / f|<0.17; The focal length f of the second lens group g2 The focal length f of the dual telecentric lens satisfies the following relationship: 0.01 < |f g2 / f|<0.08; The focal length f of the third lens group g3 The focal length f of the aforementioned telecentric lens satisfies the following relationship: 0.002 < |f g3 / f|<0.016; The focal length f of the fourth lens group g4 The focal length f of the aforementioned telecentric lens satisfies the following relationship: 0.14 < |f g4 / f|<0.

7.

3. The double telecentric lens according to claim 1, characterized in that, The first lens group includes a first prism, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis. The second lens group includes a seventh lens, an eighth lens, a ninth prism, and a tenth lens arranged sequentially along the optical axis. The third lens group includes an eleventh lens, a twelfth prism, and a thirteenth lens arranged sequentially along the optical axis. The fourth lens group includes a fourteenth lens and a fifteenth parallel plate arranged sequentially along the optical axis.

4. The double telecentric lens according to claim 3, characterized in that, The third lens and the fourth lens are cemented together to form a first cemented lens, and the focal length f of the first cemented lens is... C1 The focal length f of the dual telecentric lens satisfies the following relationship: 0.06 < |f C1 / f|<0.28; The focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy the following relationship: 1.4 <f3 / f4<1.8; The fifth lens and the sixth lens are cemented together to form a second cemented lens, the focal length f of the second cemented lens. C2 The focal length f of the aforementioned telecentric lens satisfies the following relationship: 0.05 < |f C2 / f|<0.22; The focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy the following relationship: 1.3 <f5 / f6<1.7; The seventh lens and the eighth lens are cemented together to form a third cemented lens, the focal length f of which is... C3 The focal length f of the aforementioned telecentric lens satisfies the following relationship: 0.2 < |f C3 / f|<0.75; The focal length f7 of the seventh lens and the focal length f8 of the eighth lens satisfy the following relationship: 1.2 <f7 / f8<1.6。 5. The dual telecentric lens according to claim 4, characterized in that, The sagitta SAG34 of the first cemented surface along the optical axis and the total center thickness CT34 of the first cemented lens along the optical axis satisfy the following relationship: 0.18 <SAG34 / CT34<0.22; The sagitta SAG56 of the second cemented surface along the optical axis and the total center thickness CT56 of the second cemented lens along the optical axis satisfy the following relationship: 0.21 <SAG56 / CT56<0.25; The sag SAG78 of the third cemented surface along the optical axis of the third cemented lens and the total center thickness CT78 of the third cemented lens along the optical axis satisfy the following relationship: 0.02 <SAG78 / CT78<0.04。 6. The dual telecentric lens according to claim 3, characterized in that, The third lens is a meniscus negative lens, and the fourth lens is a biconvex lens; The fifth lens is a positive meniscus lens, and the sixth lens is a negative meniscus lens; The seventh lens is a biconvex lens, and the eighth lens is a biconcave lens.

7. The dual telecentric lens according to claim 3, characterized in that, The Abbe number Vd3 of the third lens and the Abbe number Vd4 of the fourth lens satisfy the relationship: Vd3 < Vd4; the refractive index Nd3 of the third lens and the refractive index Nd4 of the fourth lens satisfy the relationship: Nd3 > Nd4. The Abbe number Vd5 of the fifth lens and the Abbe number Vd6 of the sixth lens satisfy the relationship: Vd5 > Vd6; the refractive index Nd5 of the fifth lens and the refractive index Nd6 of the sixth lens satisfy the relationship: Nd5 < Nd6. The Abbe number Vd7 of the seventh lens and the Abbe number Vd8 of the eighth lens satisfy the relationship: Vd7 > Vd8; the refractive index Nd7 of the seventh lens and the refractive index Nd8 of the eighth lens satisfy the relationship: Nd7 < Nd8.

8. The dual telecentric lens according to claim 3, characterized in that, In the third lens group, the eleventh and thirteenth lenses are biconcave lenses; The relationship between the focal length f11 of the eleventh lens, the focal length f13 of the thirteenth lens, and the focal length f of the double telecentric lens satisfies: 0.03 < (f11 + f13) / f < 0.19; The total optical length TTL of the double telecentric lens and the focal length f of the third lens group g3 The relation satisfies: 111 < TTL / f g3 <118; The air gap between the third lens group and the fourth lens group is 58.7 ± 0.5 mm.

9. The dual telecentric lens according to claim 3, characterized in that, The Abbe number Vd11 of the eleventh lens and the Abbe number Vd13 of the thirteenth lens satisfy the following relationship: Vd11 = Vd13; The refractive index Nd11 of the eleventh lens and the refractive index Nd13 of the thirteenth lens satisfy the following relationship: Nd11 = Nd13; The Abbe number Vd13 of the thirteenth lens and the Abbe number Vd12 of the twelfth prism satisfy the following relationship: Vd13 < Vd12; The refractive index Nd13 of the thirteenth lens and the refractive index Nd12 of the twelfth prism satisfy the relationship: Nd13 > Nd12.

10. The dual telecentric lens according to claim 3, characterized in that, In the fourth lens group, the fourteenth lens is a plano-convex lens with a flat object side and a convex image side. The focal length f14 of the fourteenth lens and the focal length f of the double telecentric lens satisfy the following relationship: 0.15 < f14 / f < 0.

7.

11. The double telecentric lens according to claim 3, characterized in that, The Abbe number Vd14 of the fourteenth lens and the Abbe number Vd15 of the fifteenth parallel plate satisfy the following relationship: Vd14 < Vd15; The refractive index Nd14 of the fourteenth lens and the refractive index Nd15 of the fifteenth parallel plate satisfy the relationship: Nd14 > Nd15.

12. The double telecentric lens according to claim 1, characterized in that, The entrance pupil diameter D of the double telecentric lens and the focal length f of the double telecentric lens satisfy the following relationship: 0.02≤D / 2f≤0.06; The focal length f of the dual telecentric lens satisfies the following relationship with the total optical length TTL of the dual telecentric lens and half the diagonal length ImgH of the effective pixel area of ​​the photosensitive module: 0.31≤f / (TTL×ImgH)≤1.

13.

13. An optical system, characterized in that, include: An illumination module is used to emit an illumination beam to illuminate the object under test; An optical imaging module having a dual telecentric lens as described in any one of claims 1 to 12 for receiving a light beam from the object under test; A photosensitive module, located at the image plane of the optical imaging module, is used to receive the imaging beam and convert the optical signal into an electrical signal for imaging. The optical imaging module also includes an extinction unit for absorbing or blocking non-imaging light.

14. The optical system according to claim 13, characterized in that, The extinction unit consists of a lens barrel and multiple extinction stops installed on the inner wall of the lens barrel; The extinction aperture includes a mounting part and a blocking part connected thereto; The mounting part is fixed to the lens barrel by a threaded structure on the inner wall of the lens barrel; The blocking portion extends inward from the mounting portion in a direction perpendicular to the optical axis of the dual telecentric lens to absorb or block non-imaging light.

15. A semiconductor device, characterized in that, include: The double telecentric lens as described in any one of claims 1 to 12, or the optical system as described in any one of claims 13 to 14.

Images