A dual-telecentric lens

Abstract

This application provides a telecentric lens, including a focusing illumination lens group, an alignment imaging lens group, and a focusing sensing detection lens group; the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group share a first lens group; the alignment imaging lens group and the focusing sensing detection lens group share a second lens group. This dual telecentric lens, through the rational arrangement of the lenses within the lens, achieves identical lens parameters for all three lens groups. The optical performance of each of the three lens groups can be guaranteed simply by reusing lenses, adding or removing beam-splitting prisms, and adjusting the lens spacing, thus reducing lens parameters and effectively controlling manufacturing costs. Through a reasonable structural design, it achieves the characteristics of a large field of view, high telecentricity, low distortion, and -1X imaging, effectively improving lithographic alignment and focusing accuracy.

Description

Technical Field

[0001] This application belongs to the field of optical equipment, and specifically relates to a double telecentric lens. Background Technology

[0002] The lithography machine is the most critical piece of equipment in the semiconductor chip manufacturing process, integrating cutting-edge optical, mechanical, electronic, and computing technologies. The alignment and focusing system, as a core component of the lithography machine, plays a vital role in lithography production. In existing lens structures, the alignment and imaging lens group, the focusing and illumination lens group, and the focusing and sensing lens group only share some lens groups and beam splitter prism groups. The second, fourth, and fifth lens groups are designed separately, and the telecentric lens has a variety of lens types, increasing manufacturing costs.

[0003] CN 109709665 A discloses a dual telecentric lens and optical system, which includes an optical magnification group, an aperture stop, and an imaging group along the optical path. The optical magnification group consists of seven lenses, and the imaging group consists of eleven lenses. This technology can improve the resolution and contrast of the lens and reduce the telecentricity and distortion rate of the lens. However, the parameters of these eighteen lenses are different, and they need to be designed separately, making the manufacturing process relatively complex. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this technical solution provides a dual telecentric lens. It employs a reasonable optical structure design to enable the three lens groups—alignment imaging, focus detection illumination, focus detection imaging, and focus detection fiber optic sensing—to share some optical components and use lenses with the same parameters, which greatly reduces processing costs while ensuring that the optical performance of each part meets the requirements. It has the advantages of a large field of view, high telecentricity, low distortion, and -1X imaging.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted in this application is as follows:

[0006] A dual telecentric lens includes a focus detection illumination lens group, an alignment imaging lens group, and a focus detection sensing lens group;

[0007] The focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group share the first lens group.

[0008] The alignment imaging lens group and the focus detection sensor lens group share the second lens group;

[0009] The first mirror group includes a first beam splitter arranged along the optical path direction, a first lens group with positive optical power, an aperture stop, and a second beam splitter;

[0010] The second lens group includes a third lens group with negative optical power and a third beam splitter arranged along the optical path direction, wherein a portion of the transmitted light emitted from the second beam splitter is incident on the third lens group;

[0011] The focusing illumination lens group also includes a second lens group with positive optical power, and part of the reflected light emitted from the second beam splitter is incident on the second lens group;

[0012] The alignment imaging lens group also includes a fourth lens group with positive optical power, and part of the reflected light emitted from the third beam splitter is incident on the fourth lens group;

[0013] The focus-sensing detection lens group also includes a fifth lens group with positive optical power and a fourth beam splitter arranged along the optical path direction, and part of the transmitted light emitted from the third beam splitter is incident on the fifth lens group.

[0014] As a preferred option, along the direction of the light path,

[0015] The first lens group includes 6 lenses;

[0016] And / or,

[0017] The second lens group consists of 5 lenses;

[0018] And / or,

[0019] The third lens group consists of two lenses;

[0020] And / or,

[0021] The fourth lens group consists of 3 lenses;

[0022] And / or,

[0023] The fifth lens group consists of 3 lenses.

[0024] As a preferred embodiment, the third lens group and the fourth lens group constitute the third lens group; the third lens group and the fifth lens group constitute the fourth lens group.

[0025] The lenses in the second, third, and fourth lens groups have the same optical parameters and arrangement.

[0026] Preferably, the spacing between the lenses in the second lens group, the third lens group, and the fourth lens group is different.

[0027] As a preferred embodiment, the first lens group includes a first lens cementation group and a second lens cementation group, wherein the first lens cementation group is formed by cementing together a third and a fourth lens; and the second lens cementation group is formed by cementing together a fifth and a sixth lens.

[0028] The second lens group includes a third lens cemented group, which is formed by cementing the first and second lenses together;

[0029] The third lens group includes a fourth lens cemented group, which is formed by cementing the first and second lenses together;

[0030] The first lens cementation group, the second lens cementation group, the third lens cementation group, and the fourth lens cementation group are located on both sides of the aperture stop.

[0031] As a preferred embodiment, the focal lengths of each lens group in the dual telecentric lens satisfy the following relationship:

[0032] 1.1≥F2 / F1≥0.9,

[0033] And / or,

[0034] 1.1≥F 34 / F1≥0.9,

[0035] And / or, 1.1≥F 35 / F1≥0.9;

[0036] Where: F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and F... 34 F is the combined focal length of the third and fourth lens groups. 35 This is the combined focal length of the third and fifth lens groups.

[0037] As a preferred embodiment, the focal lengths of each lens in the dual telecentric lens satisfy the following relationship:

[0038] 0.53≤f 110 / F1≤1.53, and / or, -4.32≤f 120 / F1≤-3.32, and / or, -0.98≤f 11 / F1≤0.02, and / or, -0.06≤f 12 / F1≤0.94, and / or, -3.61≤f 21 / F1≤2.61, and / or, -1.40≤f 230 / F1≤0.40, and / or, -0.07≤f 240 / F1≤0.93, and / or, 1.71≤f 250 / F1≤2.71;

[0039] Where: f 110 f 120 f 11 f 12 f 21 f 230 f 240 f 250F1 and F2 are the first lens of the first lens group, the second lens of the first lens group, the first lens cement group, the second lens cement group, the third lens cement group, the third lens of the second lens group, the fourth lens of the second lens group, the fifth lens of the second lens group, and the focal length of the first lens group, respectively.

[0040] As a preferred embodiment, the lens materials in the first lens group and the second lens group include one or more of the following: lanthanide flint glass, barium crown glass, phosphor crown glass, lanthanide flint glass, phosphor crown glass, heavy flint glass, phosphor crown glass, lanthanide crown glass, heavy crown glass, lanthanide flint glass, and lanthanide crown glass.

[0041] As a preferred embodiment, the wavelength range of the focusing illumination lens group and the focusing sensing detection lens group is 400–900 nm;

[0042] And / or, the wavelength of the aligned imaging lens group is 500–570 nm.

[0043] As a preferred embodiment, the optical paths of the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group are all dual telecentric optical paths, and the object-side and image-side telecentricity are controlled within a deviation of 0.1°.

[0044] As a preferred embodiment, the first beam splitter is a cubic structure with a side length L100≥100mm. The beam splitting surface of the first beam splitter is coated with a first beam splitting film, which has high transmission for wavelengths of 363nm~367nm and high reflection for wavelengths of 400nm~900nm.

[0045] Preferably, the distance D from the object plane of the dual telecentric lens to the object plane of the first beam splitter satisfies the following condition: 250mm≤D≤350mm.

[0046] As a preferred embodiment, the second beam splitter is a cubic structure with a side length L200 ≥ 50 mm, and the beam splitting surface of the second beam splitter is coated with a second beam splitting film; the second beam splitting film is a high reflectance film with a wavelength of 400 nm to 900 nm and a high transmittance film of 20% to 30%.

[0047] As a preferred embodiment, the third beam splitter is a cubic structure with a side length L300 ≥ 60 mm, and the beam splitting surface of the third beam splitter is coated with a third beam splitting film; the third beam splitting film is a high reflectance film with a wavelength of 400 nm to 900 nm and a high transmittance film of 30% to 40%.

[0048] As a preferred embodiment, the fourth beam splitter is a cubic structure with a side length L400≥70mm, and the beam splitting surface of the fourth beam splitter is coated with a fourth beam splitting film; the fourth beam splitting film is a high reflectance film with a wavelength of 400nm~900nm and a high transmittance film of 45%~55%.

[0049] As a preferred embodiment, the magnification of the dual telecentric lens is β = -1X.

[0050] As a preferred embodiment, the effective field of view on the object side of the dual telecentric lens is: The numerical aperture is NA = 0.05.

[0051] As a preferred embodiment, the distortion of the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group of the dual telecentric lens is <0.1%.

[0052] As a preferred embodiment, in the dual telecentric lens, the MTF of the focusing illumination lens group is ≥0.4@63lp / mm, the MTF of the alignment imaging lens group is ≥0.4@75lp / mm, and the MTF of the focusing sensing detection lens group is ≥0.4@63lp / mm.

[0053] Due to the adoption of the above technical solution, the technical advantages of this application are: This dual telecentric lens achieves identical lens parameters for the three lens groups through the reasonable arrangement of the lens elements inside the lens. The optical performance of each of the three lens groups can be guaranteed simply by reusing lenses, adding or removing beam-splitting prisms, and adjusting the lens spacing, thereby reducing lens parameters and effectively controlling processing costs. Through reasonable structural design, it achieves the characteristics of large field of view, high telecentricity, low distortion, and -1X imaging, effectively improving the accuracy of lithography alignment and focusing. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of a dual telecentric lens provided in one embodiment of this application;

[0055] Figure 2 This is a schematic diagram of the structure of a focusing illumination lens assembly provided in one embodiment of this application;

[0056] Figure 3 This is an MTF curve diagram of a focusing illumination lens group provided in one embodiment of this application;

[0057] Figure 4 The field curvature and distortion diagram of the focusing illumination lens assembly provided in one embodiment of this application;

[0058] Figure 5 This is a dot diagram of a focusing illumination lens group provided in one embodiment of this application;

[0059] Figure 6This is a schematic diagram of the alignment imaging lens assembly provided in one embodiment of this application;

[0060] Figure 7 This is an MTF curve diagram of an alignment imaging lens assembly provided in one embodiment of this application;

[0061] Figure 8 A field curvature and distortion diagram of an aligned imaging lens assembly provided in one embodiment of this application;

[0062] Figure 9 This is a dot diagram of an alignment imaging lens group provided in one embodiment of this application;

[0063] Figure 10 This is a schematic diagram of the structure of a focus-detecting lens assembly provided in one embodiment of this application;

[0064] Figure 11 This is an MTF curve of a focus-sensing detection lens group provided in one embodiment of this application;

[0065] Figure 12 This is a field curvature and distortion diagram of a focus-sensing detection lens group provided in one embodiment of this application;

[0066] Figure 13 This is a dot diagram of a focus-sensing detection lens group provided in one embodiment of this application.

[0067] In the diagram: 100 - First beam splitter; 200 - Second beam splitter; 300 - Third beam splitter; 400 - Fourth beam splitter; A - First lens group; B - Second lens group; C - Third lens group; D - Fourth lens group; E - Fifth lens group; A1 - First lens cementation group; A2 - Second lens cementation group; B1 - Third lens cementation group; C1 - Fourth lens cementation group; S - Aperture stop Detailed Implementation

[0068] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0069] To facilitate understanding of the dual telecentric lenses provided in the embodiments of this application, the relevant terms used in this application are explained as follows:

[0070] With the lens as the boundary, the side where the object is located is called the object side, and the surface of the lens closest to the object side is called the object side surface.

[0071] With the lens as the boundary, the side on which the image of the object is located is called the image side, and the surface of the lens closest to the image side is called the image-side surface.

[0072] Positive optical power, also known as positive refractive power, indicates that a lens has a positive focal length.

[0073] Negative optical power, also known as negative refractive power, indicates that a lens has a negative focal length.

[0074] Focal length is a measure of the convergence or divergence of light in an optical system. It refers to the distance from the optical center of the lens to the focal point where parallel light converges when incident.

[0075] like Figure 1 , Figure 2 , Figure 6 , Figure 10 As shown, this application provides a dual telecentric lens, which includes a focus detection illumination lens group, an alignment imaging lens group, and a focus detection sensing lens group.

[0076] The focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group share the first lens group.

[0077] The alignment imaging lens group and the focus detection sensor lens group share the second lens group;

[0078] The first mirror group includes a first beam splitter 100 arranged along the optical path direction, a first lens group A with positive focal length, an aperture stop S, and a second beam splitter 200.

[0079] The second lens group includes a third lens group C with negative optical power arranged along the optical path direction and a third beam splitter 300. Part of the transmitted light emitted from the second beam splitter 200 is incident on the third lens group C.

[0080] The focusing illumination lens group also includes a second lens group B with positive optical power, and part of the reflected light emitted from the second beam splitter 200 is incident on the second lens group B.

[0081] The alignment imaging lens group also includes a fourth lens group D with positive optical power, and part of the reflected light emitted from the third beam splitter 300 is incident on the fourth lens group D.

[0082] The focus-sensing detection lens group also includes a fifth lens group E with positive optical power and a fourth beam splitter 400 arranged along the optical path direction. The polarized transmitted light emitted from the third beam splitter 300 is incident on the fifth lens group E.

[0083] Due to the adoption of the above technical solution, the technical advantages of this application are as follows: This technical solution describes a dual telecentric lens for focusing illumination, focusing imaging, and alignment imaging in a lithography machine. Through a near-symmetrical structural layout based on the aperture stop S, it achieves high telecentricity and -1X imaging effects in both the object and image sides. Through reasonable optical design, the focusing illumination, alignment imaging, and focusing sensing detection parts use lenses with the same parameters. The functions of the three parts are achieved by adjusting the lens spacing and adding or removing beam splitters, effectively reducing the types of lenses and lowering costs. The optical structure design using a total of 19 lenses effectively reduces the number of lenses. The fewer lenses effectively reduce the cumulative tolerance in lens assembly, while achieving a large field of view, high telecentricity, low distortion, and -1X imaging effects.

[0084] In some embodiments, such as Figure 1 , Figure 2 , Figure 6 , Figure 10 As shown, along the direction of the light path,

[0085] The first lens group A includes 6 lenses;

[0086] And / or,

[0087] The second lens group B consists of 5 lenses;

[0088] And / or,

[0089] The third lens group C consists of two lenses;

[0090] And / or,

[0091] The fourth lens group D consists of 3 lenses;

[0092] And / or,

[0093] The fifth lens group E consists of 3 lenses.

[0094] In some embodiments, the third lens group C and the fourth lens group D form a third lens group; the third lens group C and the fifth lens group E form a fourth lens group; the third lens group and the fourth lens group achieve optical path allocation for the alignment imaging and focus sensing detection parts by sharing the third lens group C, thereby reducing the number of lens types and lowering costs while ensuring that the functions of the two parts of the lens meet the requirements.

[0095] The lenses in the second lens group B, the third lens group, and the fourth lens group have the same optical parameters and arrangement. By using this method for reasonable optical design, while ensuring the functions of focusing illumination, alignment imaging, and alignment sensing detection are achieved, the types of lenses used are reduced, the types of molds used in lens processing are reduced, and the processing cost is lowered.

[0096] In some embodiments, the spacing between the lenses in the second lens group B, the third lens group, and the fourth lens group is different. By designing a reasonable spacing between the lenses in each lens group, the purpose of achieving three functions using the same type of lenses can be realized.

[0097] In some embodiments, the first lens group A includes a first lens cementation group A1 and a second lens cementation group A2, wherein the first lens cementation group A1 is formed by cementing together a third and a fourth lens; and the second lens cementation group A2 is formed by cementing together a fifth and a sixth lens.

[0098] The second lens group B includes a third lens cemented group B1, which is formed by cementing the first and second lenses together;

[0099] The third lens group C includes a fourth lens cemented group C1, which is formed by cementing the first and second lenses together;

[0100] The first lens cement group A1, the second lens cement group A2, the third lens cement group B1, and the fourth lens cement group C1 are located on both sides of the aperture stop S. This arrangement is beneficial for achieving high telecentricity, low distortion, and -1X imaging of the lens.

[0101] In some embodiments, the focal lengths of each lens group in the dual telecentric lens satisfy the following relationship:

[0102] 1.1≥F2 / F1≥0.9,

[0103] And / or,

[0104] 1.1≥F 34 / F1≥0.9,

[0105] And / or, 1.1≥F 35 / F1≥0.9;

[0106] Where: F1 is the focal length of the first lens group A, F2 is the focal length of the second lens group B, F 34 F is the combined focal length of the third lens group C and the fourth lens group D. 35 It is the combined focal length of the third lens group C and the fifth lens group E.

[0107] This setup is beneficial for achieving high telecentricity, low distortion, and -1X imaging of the lens.

[0108] In some embodiments, the focal lengths of the lenses in the dual telecentric lens satisfy the following relationship:

[0109] 0.53≤f 110 / F1≤1.53, and / or, -4.32≤f 120 / F1≤-3.32, and / or, -0.98≤f 11 / F1≤0.02, and / or, -0.06≤f 12 / F1≤0.94, and / or, -3.61≤f 21 / F1≤2.61, and / or, -1.40≤f 230 / F1≤0.40, and / or, -0.07≤f 240 / F1≤0.93, and / or, 1.71≤f 250 / F1≤2.71;

[0110] Where: f 110 f 120 f 11 f 12 f 21 f 230 f 240 f 250 F1 and F2 are the first lens of the first lens group A, the second lens of the first lens group A, the first lens cement group A1, the second lens cement group A2, the third lens cement group B1, the third lens of the second lens group B, the fourth lens of the second lens group B, the fifth lens of the second lens group B, and the focal length of the first lens group A, respectively.

[0111] In some embodiments, the lens materials in the first lens group A and the second lens group B include one or more of lanthanide flint glass, barium crown glass, phosphor crown glass, lanthanide flint glass, phosphor crown glass, heavy flint glass, phosphor crown glass, lanthanide crown glass, heavy crown glass, lanthanide flint glass, and lanthanide crown glass.

[0112] In some embodiments, the wavelength range of the focusing illumination lens group and the focusing sensing detection lens group is 400–900 nm;

[0113] And / or, the wavelength of the aligned imaging lens group is 500–570 nm.

[0114] In some embodiments, the optical paths of the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group are all dual telecentric optical paths, and the object-side and image-side telecentricity are controlled within a deviation of 0.1°.

[0115] In some embodiments, the first beam splitter 100 is a cubic structure with a side length L100≥100mm. The beam splitting surface of the first beam splitter 100 is coated with a first beam splitting film. The first beam splitting film has high transmission at wavelengths of 363nm~367nm and high reflection at wavelengths of 400nm~900nm.

[0116] In some embodiments, the distance D from the object plane of the dual telecentric lens to the object plane of the first beam splitter 100 satisfies the following condition: 250mm≤D≤350mm.

[0117] In some embodiments, the second beam splitter 200 is a cubic structure with a side length L200 ≥ 50 mm, and the beam splitting surface of the second beam splitter 200 is coated with a second beam splitting film; the second beam splitting film is a high reflectance film with a wavelength of 400 nm to 900 nm and a high transmittance film with a wavelength of 20% to 30% and a wavelength of 70% to 80%.

[0118] In some embodiments, the third beam splitter 300 has a cubic structure with a side length L300 ≥ 60 mm, and the beam splitting surface of the third beam splitter 300 is coated with a third beam splitting film; the third beam splitting film is a 30%–40% high reflectivity and 60%–70% high transmittance film with a wavelength of 400 nm to 900 nm.

[0119] In some embodiments, the fourth beam splitter 400 has a cubic structure with a side length L400≥70mm, and the beam splitting surface of the fourth beam splitter 400 is coated with a fourth beam splitting film; the fourth beam splitting film is a high reflectance film with a wavelength of 400nm~900nm and a high transmittance film of 45%~55%.

[0120] In some embodiments, the magnification of the dual telecentric lens is β = -1X.

[0121] In some embodiments, the effective field of view on the object side of the dual telecentric lens is The numerical aperture is NA = 0.05.

[0122] In some embodiments, the distortion of the focus detection illumination lens group, the alignment imaging lens group, and the focus detection sensing lens group of the dual telecentric lens is <0.1%.

[0123] In some embodiments, in the dual telecentric lens, the MTF of the focusing illumination lens group is ≥0.4@63lp / mm, the MTF of the alignment imaging lens group is ≥0.4@75lp / mm, and the MTF of the focusing sensing detection lens group is ≥0.4@63lp / mm.

[0124] In one specific embodiment of the present invention, a double telecentric lens is provided, and the parameters of each optical component in the telecentric lens are shown in the table below:

[0125] Table 1. Parameter list of each lens in the first beam splitter 100 and the first lens group A

[0126]

[0127] Table 2. Parameter list of each lens in the second beam splitter 200 and the second lens group B.

[0128]

[0129] Table 3. Parameter list of each lens in the second beam splitter 200 and the third lens group C.

[0130]

[0131] Table 4. Parameter list of each lens in the third beam splitter 300 and the fourth lens group D.

[0132]

[0133] Table 5 lists the parameters of each lens in the third beam splitter 300, the fifth lens group E, and the fourth beam splitter 400.

[0134]

[0135]

[0136] In this embodiment, the focal length F1 of the first lens group A is 349.483, the focal length F2 of the second lens group B is 352.689, and the combined focal length F of the third lens group C and the fourth lens group D is... 34 =352.728, the combined focal length F of the third lens group C and the fifth lens group E 35 =354.048; the focal length is in mm.

[0137] The focal lengths of the first lens element of the first lens group A, the second lens element of the first lens group A, the first cemented lens group A1, the second cemented lens group A2, the third cemented lens group B1, the third lens element of the second lens group B, the fourth lens element of the second lens group B, and the fifth lens element of the second lens group B are f respectively. 110 =361.255, f 120 =-1335.139、f 11 =-168.599, f 12 =154.392, f 21 =-1087.48, f 230 =-314.843, f 240 =148.797, f 250 =773.333; the focal length is in mm.

[0138] In this embodiment, the object distance of the dual telecentric lens is 300mm, the magnification is β=-1X, and the effective field of view is... The image-side numerical aperture is NA = 0.05, which meets the requirements for working distance. The optical paths of the provided focusing illumination lens group, alignment imaging lens group, and focusing sensor detection lens group are all dual telecentric optical paths, with object-side telecentricity < 0.01°. Specifically, the image-side telecentricity of the focusing illumination lens group is 0.07°, the image-side telecentricity of the alignment imaging lens group is 0.055°, and the image-side telecentricity of the focusing sensor detection lens group is 0.098°.

[0139] Figure 3 The MTF curve of the focusing illumination lens group provided in this embodiment shows that the MTF of each field of view is >0.4@63lp / mm, which meets the focusing illumination resolution requirements. Figure 4 The field curvature and distortion diagrams for the focusing illumination lens group are shown, with the maximum distortion being 0.0819%, indicating minimal distortion. Figure 5 The image shows a dot plot of the focusing illumination lens group. The blur spots in the central and peripheral fields of view are mostly within the radius of the Airy disk. The energy concentration and aberration correction of the on-axis and off-axis points are good, achieving ideal resolution.

[0140] Figure 7 The MTF curve of the alignment imaging lens group provided in this embodiment shows that the MTF of each field of view is >0.4@75lp / mm, which meets the alignment imaging resolution requirements. Figure 8 The field curvature and distortion diagram of the aligned imaging lens group provided in this embodiment shows that the maximum distortion is 0.0665%, which is extremely small. Figure 9 The diagram shows the alignment and imaging lens group provided in this embodiment. The blur spots in both the central and peripheral fields of view are within the radius of the Airy disk. The energy concentration and aberration correction of the on-axis and off-axis points are good, achieving the ideal resolution.

[0141] Figure 11 The MTF curve of the focus detection sensor lens group provided in this embodiment is shown. The MTF of each field of view is >0.4@63lp / mm, which meets the requirements of focus detection imaging and focus sensor resolution. Figure 12 The field curvature and distortion diagrams of the focus sensing detection lens group provided in this embodiment are shown, where the maximum distortion is 0.0885%, indicating minimal distortion. Figure 13 The image shows a dot plot of the focus sensing lens group provided in this embodiment. The blur spots in the center and edge fields of view are mostly within the radius of the Airy disk. The energy concentration and aberration correction of the on-axis and off-axis points are good, achieving ideal resolution.

Claims

1. A double telecentric lens, characterized in that, The dual telecentric lens includes a focus detection illumination lens group, an alignment imaging lens group, and a focus detection sensor detection lens group. The focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group share the first lens group. The alignment imaging lens group and the focus detection sensor lens group share the second lens group; The first mirror group includes a first beam splitter arranged along the optical path direction, a first lens group with positive optical power, an aperture stop, and a second beam splitter; The second lens group includes a third lens group with negative optical power arranged along the optical path direction and a third beam splitter. The polarized transmitted light emitted from the second beam splitter is incident on the third lens group. The focusing illumination lens group also includes a second lens group with positive optical power, and the polarized reflected light emitted from the second beam splitter is incident on the second lens group; The alignment imaging lens group also includes a fourth lens group with positive optical power, and the polarized reflected light emitted from the third beam splitter is incident on the fourth lens group; The focus-sensing detection lens group also includes a fifth lens group with positive optical power and a fourth beam splitter arranged along the optical path direction. The polarized transmitted light emitted from the third beam splitter is incident on the fifth lens group.

2. The double telecentric lens according to claim 1, characterized in that: Along the direction of the light path, The first lens group includes 6 lenses; And / or, The second lens group consists of 5 lenses; And / or, The third lens group consists of two lenses; And / or, The fourth lens group consists of 3 lenses; And / or, The fifth lens group consists of 3 lenses.

3. The double telecentric lens according to claim 2, characterized in that: The third lens group and the fourth lens group form the third lens group; the third lens group and the fifth lens group form the fourth lens group; The lenses in the second, third, and fourth lens groups have the same optical parameters and arrangement.

4. The double telecentric lens according to claim 3, characterized in that: The spacing between the lenses in the second, third, and fourth lens groups is different.

5. The double telecentric lens according to claim 2, characterized in that: The first lens group includes a first lens cementation group and a second lens cementation group. The first lens cementation group is formed by cementing together the third and fourth lenses; the second lens cementation group is formed by cementing together the fifth and sixth lenses. The second lens group includes a third lens cemented group, which is formed by cementing together the first and second lenses; The third lens group includes a fourth lens cemented group, which is formed by cementing the first and second lenses together. The second and fourth lens cementation groups are symmetrically arranged relative to the aperture stops.

6. The double telecentric lens according to claim 2, characterized in that: The focal lengths of each lens group in the dual telecentric lens satisfy the following relationship: 1.1≥F2 / F1≥0.9, And / or, 1.1≥F 34 / F1≥0.9, And / or, 1.1≥F 35 / F1≥0.9; Where: F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, and F... 34 F is the combined focal length of the third and fourth lens groups. 35 This is the combined focal length of the third and fifth lens groups.

7. The double telecentric lens according to claim 5, characterized in that: The focal lengths of the lenses in the dual telecentric lens satisfy the following relationship: 0.53≤f 110 / F1≤1.53, and / or, -4.32≤f 120 / F1≤-3.32, and / or, -0.98≤f 11 / F1≤0.02, and / or, -0.06≤f 12 / F1≤0.94, and / or, -3.61≤f 21 / F1≤2.61, and / or, -1.40≤f 230 / F1≤0.40, and / or, -0.07≤f 240 / F1≤0.93, and / or, 1.71≤f 250 / F1≤2.71; Where: f 110 f 120 f 11 f 12 f 21 f 230 f 240 f 250 F1 and F2 are the first lens of the first lens group, the second lens of the first lens group, the first lens cement group, the second lens cement group, the third lens cement group, the third lens of the second lens group, the fourth lens of the second lens group, the fifth lens of the second lens group, and the focal length of the first lens group, respectively.

8. The double telecentric lens according to claim 1, characterized in that: The lens materials in the first lens group and the second lens group include one or more of the following: lanthanide flint glass, barium crown glass, phosphor crown glass, lanthanide flint glass, phosphor crown glass, heavy flint glass, phosphor crown glass, lanthanide crown glass, heavy crown glass, lanthanide flint glass, and lanthanide crown glass.

9. The double telecentric lens according to claim 1, characterized in that: The wavelength range of the focusing illumination lens group and the focusing sensing detection lens group is 400~900nm; And / or, the wavelength of the aligned imaging lens group is 500~570nm.

10. The double telecentric lens according to claim 1, characterized in that: The optical paths of the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group are all dual telecentric optical paths, and the object-side and image-side telecentricity are controlled within a deviation of 0.1°.

11. The double telecentric lens according to claim 1, characterized in that: The first beam splitter is a cubic structure with a side length L100≥100mm. The beam splitting surface of the first beam splitter is coated with a first beam splitting film. The first beam splitting film has high transmission at wavelengths of 363nm~367nm and high reflection at wavelengths of 400nm~900nm.

12. The double telecentric lens according to claim 11, characterized in that: The distance D from the object plane of the dual telecentric lens to the object plane of the first beam splitter satisfies the following condition: 250mm≤D≤350mm.

13. The double telecentric lens according to claim 1, characterized in that: The second beam splitter is a cubic structure with a side length L200≥50mm. The beam splitting surface of the second beam splitter is coated with a second beam splitting film. The second beam splitting film is a high reflectance film with a wavelength of 400nm~900nm and a high transmittance film with a wavelength of 20%~30% and a wavelength of 70%~80%.

14. The double telecentric lens according to claim 1, characterized in that: The third beam splitter is a cubic structure with a side length L300≥60mm. The beam splitting surface of the third beam splitter is coated with a third beam splitting film. The third beam splitting film is a high reflectance film with a wavelength of 400nm~900nm and a high transmittance film of 30%~40% and 60%~70%.

15. The double telecentric lens according to claim 1, characterized in that: The fourth beam splitter is a cubic structure with a side length L400≥70mm. The beam splitting surface of the fourth beam splitter is coated with a fourth beam splitting film. The fourth beam splitting film is a high reflectance film with a wavelength of 400nm~900nm and a high transmittance film of 45%~55%.

16. The double telecentric lens according to claim 1, characterized in that: The magnification of the dual telecentric lens is β=-1X.

17. The double telecentric lens according to claim 1, characterized in that: The object-side effective field of view of the dual telecentric lens is φ≥50mm, and the image-side numerical aperture is NA=0.

05.

18. The double telecentric lens according to claim 1, characterized in that: The distortion of the focusing illumination lens group, the alignment imaging lens group, and the focusing sensing detection lens group of the dual telecentric lens is <0.1%.

19. The double telecentric lens according to claim 1, characterized in that: In the dual telecentric lens, the MTF of the focusing illumination lens group is ≥0.4 @63lp / mm, the MTF of the alignment imaging lens group is ≥0.4 @75lp / mm, and the MTF of the focusing sensing detection lens group is ≥0.4 @63lp / mm.

Images