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CN-116699822-B - Large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective lens

CN116699822BCN 116699822 BCN116699822 BCN 116699822BCN-116699822-B

Abstract

The invention relates to the technical field of optical lenses, and discloses a large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective lens which comprises a first lens group, a second lens group, a diaphragm, a third lens group and a fourth lens group which are sequentially arranged from left to right along an optical axis. The first lens group consists of a first lens, a fifth lens, a sixth lens, a eighth lens, a ninth lens, a fourteenth lens, a thirteenth lens and a fourteenth lens. In the beneficial effect of the microscope objective, the field of view of the microscope objective reaches 2.3mm, the working distance reaches 8.5mm, and the transverse aberration is not more than 2.5um. Meanwhile, each view field has excellent imaging quality, and chromatic aberration is well corrected within a wave band of 400-700 nm. In addition, the invention also considers the edge thickness, the center thickness, the blocking rate and the air interval of each lens in design, thereby reducing the processing and adjusting difficulty.

Inventors

  • HUO DAYUN
  • XI FANGFANG
  • LI BINGJIE

Assignees

  • 锡凡半导体无锡有限公司

Dates

Publication Date
20260512
Application Date
20230525

Claims (11)

  1. 1. The large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective is characterized by comprising a first lens group (G1), a second lens group (G2), a third lens group (G3) and a fourth lens group (G4) which are sequentially arranged along an optical axis from an object space to an image space; A Stop (STO) is arranged between the second lens group (G2) and the third lens group (G3); The first lens group (G1), the second lens group (G2), the third lens group (G3) and the fourth lens group (G4) have optical power distribution which accords with the odd symmetry of negative-positive; The first lens group (G1) has negative focal power and consists of a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4) and a fifth lens (L5); the second lens group (G2) has negative focal power and consists of a sixth lens (L6), a seventh lens (L7) and an eighth lens (L8); The third lens group (G3) has positive optical power, and is composed of a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), and a twelfth lens (L12); the fourth lens group (G4) has positive optical power and is composed of a thirteenth lens (L13) and a fourteenth lens (L14).
  2. 2. The large-field long-working-distance low-aberration plano-field apochromatic microscope objective of claim 1, wherein a ratio of a focal length fg3 of the third lens group (G3) and a focal length fg4 of the fourth lens group (G4) to a total focal length f of the microscope objective satisfies the following stable characteristic relation: relation 1:1.78 is less than or equal to fg3/f is less than or equal to 3.23; relation 2:0.74 is less than or equal to fg4/f is less than or equal to 0.97.
  3. 3. The large-field-of-view long-working-distance low-aberration flat-field apochromatic microscope objective lens according to claim 1, wherein the sixth lens (L6), the seventh lens (L7) and the eighth lens (L8) are three cemented lenses, the ninth lens (L9) and the tenth lens (L10) are two cemented lenses, and the eleventh lens (L11) and the twelfth lens (L12) are two cemented lenses.
  4. 4. A large field of view long working distance low aberration flat field apochromatic microscope objective according to claim 3, wherein the focal length (f 7) of the seventh lens (L7), the focal length (f 10) of the tenth lens (L10), the focal length (f 11) of the eleventh lens (L11) are made of ultra-low dispersion glass material HFK95N to achieve achromatism, and the focal lengths f7, f10, f11 of the respective lenses and the focal length fg2 of the second lens group (G2), the focal length fg3 of the third lens group (G3) satisfy the following stable characteristic relation: relation 3, f7/fg2 is less than or equal to-0.40 and less than or equal to-0.06; Relation 4:0.45 is less than or equal to f10/fg3 is less than or equal to 0.91; The relation formula is 5:0.42≤f11/fg 3≤0.81.
  5. 5. A large field of view long working distance low aberration flat field apochromatic microscope objective according to claim 1 wherein the fourteenth lens (L14) has positive refractive power to convert light from the observer into converging light and direct it to the thirteenth lens (L13), the concave radius of curvature r24 of the fourteenth lens (L14) near the observer and the total focal length f satisfying the following stable characteristic relation: relation 6:0.585 is less than or equal to r24/f is less than or equal to 0.734.
  6. 6. The large-field long-working-distance low-aberration flat-field apochromatic microscope objective lens as claimed in claim 1, wherein the focal length f4 of the fourth lens (L4) and the focal length fg1 of the first lens group (G1) satisfy the following stable characteristic relation: The relation 7:0.019 is less than or equal to |f4/fg1 is less than or equal to 0.129.
  7. 7. The large-field long-working-distance low-aberration flat-field apochromatic microscope objective lens of claim 1, wherein the total focal length f of the microscope objective lens is 19-21 mm, and the focal length of the optical system is 94-96 mm.
  8. 8. The large-field-of-view long-working-distance low-aberration flat-field apochromatic microscope objective lens as claimed in claim 1, wherein a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4) and a fifth lens (L5) in the first lens group (G1) are made of glass materials, the light refractive index and the abbe number of the first lens (L1) are respectively n1 and v1, the light refractive index and the abbe number of the second lens (L2) are respectively n2 and v2, the light refractive index and the abbe number of the third lens (L3) are respectively n3 and v3, the light refractive index and the abbe number of the fourth lens (L4) are respectively n4 and v4, the light refractive index and the abbe number of the fifth lens (L5) are respectively n5 and v5, and the light refractive indexes of the first lens (L1) -fifth lens (L5) satisfy the following ranges: 1.8≤n1≤2.0,23≤v1≤25;1.9≤n2≤2.1,17≤v2≤19;1.5≤n3≤1.7,40≤v3≤42;1.9≤n4≤2.1,17≤v4≤19;1.7≤n5≤1.9,44≤v5≤46.
  9. 9. The large-field-of-view long-working-distance low-aberration flat-field apochromatic microscope objective of claim 1, wherein the sixth lens (L6), the seventh lens (L7) and the eighth lens (L8) in the second lens group (G2) are all made of glass materials, and the optical refractive index and abbe number of the sixth lens (L6) are n6 and v6, respectively, and the optical refractive index and abbe number of the seventh lens (L7) are n7 and v7, respectively; the light refractive index and the Abbe number of the eighth lens (L8) are respectively n8 and v8, and the light refractive index and the Abbe number of the sixth lens (L6) to the eighth lens (L8) meet the following value ranges: 1.6≤n6≤1.8,40≤v6≤42;1.4≤n7≤1.6,94≤v7≤96;1.9≤n8≤2.1,17≤v8≤19。
  10. 10. A large-field-of-view long-working-distance low-aberration flat-field apochromatic microscope objective according to claim 1, characterized in that a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), and a twelfth lens (L12) in the third lens group (G3) are each made of a glass material, the optical refractive index and Abbe number of the ninth lens (L9) are n9 and v9, respectively, the optical refractive index and Abbe number of the tenth lens (L10) are n10 and v10, respectively, the optical refractive index and Abbe number of the eleventh lens (L11) are n11 and v11, respectively, the optical refractive index and Abbe number of the twelfth lens (L12) are n12 and v12, respectively, The light refractive index and Abbe number of the ninth lens (L9) to the twelfth lens (L12) satisfy the following value ranges: 1.9≤n9≤2.1,17≤v9≤19;1.4≤n10≤1.6,94≤v10≤96;1.4≤n11≤1.6,94≤v11≤96;1.4≤n12≤1.6,66≤v12≤68。
  11. 11. The large-field long-working-distance low-aberration flat-field apochromatic microscope objective of claim 1, wherein a thirteenth lens (L13) and a fourteenth lens (L14) in the fourth lens group (G4) are both made of glass materials, and the optical refractive index and abbe number of the thirteenth lens (L13) are n13 and v13, respectively, and the optical refractive index and abbe number of the fourteenth lens (L14) are n14 and v14, respectively; The light refractive indexes and Abbe numbers of the thirteenth lens (L13) and the fourteenth lens (L14) meet the following value ranges that n13 is more than or equal to 1.7 and less than or equal to 1.9,27 and v13 is more than or equal to 29, and n14 is more than or equal to 1.9 and less than or equal to 2.1,17 and v14 is more than or equal to 19.

Description

Large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective lens Technical Field The invention relates to a microscope objective, in particular to a large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective. Background Microscope objectives are the most important component of a microscope, and their imaging quality directly affects the overall performance of the microscope. With development of microscopic imaging technology, a scientific research microscope is required to have a larger field of view and higher imaging quality. A large field of view means that the microscope is able to provide images of a larger field of view, and a high imaging quality means a higher degree of reduction of the real image. To do this, the aberrations of the microscope objective need to be optimized more perfectly, also taking into account the aberration correction of the large field of view at the edge of the design. Meanwhile, the microscope objective with long working distance enables the compatibility of the light path construction to be stronger, and the microscope objective can be widely applied to scenes such as wafer detection, probe station, vacuum environment sample observation and the like. Along with the expansion of diversified application scenes of scientific research experiments, the requirements for the microscope objectives with large field of view, long working distance and low aberration are increasingly larger. The traditional design is not mature in technology, cannot consider all aspects, and only can selectively reserve some parameter indexes. For example CN114326071a states that conventional objective design techniques have to make a balance between numerical aperture, flatness and chromatic aberration correction. Therefore, how to simultaneously ensure that the multi-dimensional performance parameters of the microscope objective can meet the requirements of application scenes, and design a more comprehensively optimized modern lens is a problem to be solved. Disclosure of Invention The invention aims to provide a scientific research grade flat field apochromatic microscope objective lens which has a large field of view and an ultra-long working distance and can simultaneously meet high-quality imaging. The technical scheme adopted by the invention is as follows: The large-view-field long-working-distance low-aberration flat-field apochromatic microscope objective consists of a first lens group (G1), a second lens group (G2), a third lens group (G3) and a fourth lens group (G4) which are sequentially arranged along an optical axis from an object space to an image space; A Stop (STO) is arranged between the second lens group (G2) and the third lens group (G3); The first lens group (G1), the second lens group (G2), the third lens group (G3) and the fourth lens group (G4) are in accordance with an odd symmetry of negative-positive in power distribution. It is further characterized by: the ratio of the focal length fg3 of the third lens group (G3) and the focal length fg4 of the fourth lens group (G4) to the total focal length f of the microscope objective satisfies the following stable characteristic relation: relation 1:1.78 is less than or equal to fg3/f is less than or equal to 3.23; relation 2:0.74 is less than or equal to fg4/f is less than or equal to 0.97. The first lens group (G1) has negative focal power and consists of a first lens (L1), a second lens (L2), a third lens (L3), a fourth lens (L4) and a fifth lens (L5); the second lens group (G2) has negative focal power and consists of a sixth lens (L6), a seventh lens (L7) and an eighth lens (L8); The third lens group (G3) has positive optical power, and is composed of a ninth lens (L9), a tenth lens (L10), an eleventh lens (L11), and a twelfth lens (L12); the fourth lens group (G4) has positive optical power and is composed of a thirteenth lens (L13) and a fourteenth lens (L14). The sixth lens (L6), the seventh lens (L7) and the eighth lens (L8) are three cemented lenses, the ninth lens (L9) and the tenth lens (L10) are two cemented lenses, and the eleventh lens (L11) and the twelfth lens (L12) are two cemented lenses. The focal length (f 7) of the seventh lens (L7), the focal length (f 10) of the tenth lens (L10) and the focal length (f 11) of the eleventh lens (L11) are made of ultra-low dispersion glass material HFK95N to realize achromatism, and the focal lengths f7, f10 and f11 of the lenses and the focal length fg2 of the second lens group (G2) and the focal length fg3 of the third lens group (G3) satisfy the following stable characteristic relation: relation 3, f7/fg2 is less than or equal to-0.40 and less than or equal to-0.06; Relation 4:0.45 is less than or equal to f10/fg3 is less than or equal to 0.91; The relation formula is 5:0.42≤f11/fg 3≤0.81. The fourteenth lens (L14) has positive refractive power, converts light from the object to converging light a