Wide-angle astronomical eyepiece

Abstract

The invention discloses a wide-angle astronomical eyepiece, which comprises a diaphragm, a first lens group and a second lens group, and is characterized in that the first lens group sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side; the second lens group sequentially comprises a seventh lens, an eighth lens, a ninth lens and a tenth lens from the object side to the image side; the first lens and the second lens, the fourth lens and the fifth lens, and the eighth lens and the ninth lens are respectively glued; the focal power of the first lens group is phi F, the focal length of the first lens is F1, the refractive index of the first lens is N1, the Abbe number of the first lens is V1, the focal length of the sixth lens is F6, and the following relational expressions are met: 0.42 lt; f1 / [phi] Flt; 0.65, 0.65; 1.70 lt, 1.70 lt; n1lt; 1.85, 1.85; 35 lt; v1lt; 65; 0.028 [mu] m; f < 6 > / [phi] F < lt >; and-0.021,-0.021. The wide-angle astronomical eyepiece can better control chromatic aberration, so that the chromatic dispersion phenomenon is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of optical systems, and in particular to a wide-angle astronomical eyepiece. Background Art

[0002] With the improvement of the quality of life and the growing enthusiasm for exploring nature, outdoor activities, especially astronomical observation, have become one of the popular leisure activities for the public. Traditional ground-based landscape observations can no longer meet the growing curiosity and pursuit of the ultimate experience of modern people. Therefore, deep-space astronomical observations have gradually become a new focus of attention. However, despite the increasing application of large deep-space astronomical telescopes, the eyepieces used in conjunction with them have certain limitations.

[0003] The common deep-space astronomical telescope eyepieces on the market currently have problems such as small angle and large focal length or small angle and small focal length. They have simple structures, incomplete chromatic aberration correction, short exit pupil distance, and cramped visual experience, and can only achieve the effect of just being able to see. Summary of the invention

[0004] The technical problem to be solved by the present invention is that common deep space astronomical telescope eyepieces have the problem of large focal length at small angles or small focal length at small angles, simple structure, incomplete chromatic aberration correction, short exit pupil distance, cramped visual experience, and only meet the effect of just being able to see.

[0005] In order to solve the above technical problems, the present invention provides a wide-angle astronomical eyepiece, which includes an aperture, a first lens group and a second lens group in order from the object side to the image side, wherein the first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens in order from the object side to the image side; and the second lens group includes a seventh lens, an eighth lens, a ninth lens and a tenth lens in order from the object side to the image side;

[0006] The first lens has positive focal power, the second lens has negative focal power, the third lens has positive focal power, the fourth lens has negative focal power, the fifth lens has positive focal power, the sixth lens has negative focal power, the seventh lens has negative focal power, the eighth lens has negative focal power, the ninth lens has positive focal power, the tenth lens has negative focal power, and the first lens is cemented to the second lens, the fourth lens is cemented to the fifth lens, and the eighth lens is cemented to the ninth lens;

[0007] The focal power of the first lens group is ΦF, the focal length of the first lens is F1, the refractive index of the first lens is N1, the Abbe number of the first lens is V1, the focal length of the sixth lens is F6, and the following relationship is satisfied:

[0008] 0.42 <F1 / ΦF<0.65;

[0009] 1.70 <N1<1.85;

[0010] 35 <V1<65;

[0011] -0.028 <F6 / ΦF<-0.021。

[0012] Furthermore, the focal length of the second lens is F2, the refractive index of the second lens is N2, the Abbe number of the second lens is V2, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the second lens is T2, and satisfies the following relationship:

[0013] -0.35 <F2 / ΦF<-0.20;

[0014] 1.85 <N2<2.00;

[0015] 17 <V2<35;

[0016] 0.015 <T2 / L SR <0.035.

[0017] Furthermore, the focal length of the third lens is F3, the refractive index of the third lens is N3, the Abbe number of the third lens is V3, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the third lens is T3, the distance between the second lens and the third lens is d2, and the following relationship is satisfied:

[0018] 0.25 <F3 / ΦF<0.4;

[0019] 1.7 <N3<1.95;

[0020] 45 <V3<65;

[0021] 0.14 <T3 / L SR <0.18;

[0022] 0.0050 <d2 / L SR <0.0055.

[0023] Furthermore, the focal length of the fourth lens is F4, the refractive index of the fourth lens is N4, the Abbe number of the fourth lens is V4, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the fourth lens is T4, the distance between the third lens and the fourth lens is d3, and the following relationship is satisfied:

[0024] -0.21 <F4 / ΦF<-0.11;

[0025] 1.75 <N4<1.85;

[0026] 17 <V4<35;

[0027] 0.015 <T4 / L SR <0.035;

[0028] 0.0050 <d3 / L SR <0.0055.

[0029] Furthermore, the focal length of the fifth lens is F5, the refractive index of the fifth lens is N5, the Abbe number of the fifth lens is V5, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the fifth lens is T5, and satisfies the following relationship:

[0030] 0.31 <F5 / ΦF<0.45;

[0031] 1.7 <N5<1.89;

[0032] 40 <V5<60;

[0033] 0.14 <T5 / L SR <0.21.

[0034] Furthermore, the refractive index of the sixth lens is N6, the Abbe number of the sixth lens is V6, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the sixth lens is T6, the distance between the fifth lens and the sixth lens is d4, and the following relationship is satisfied:

[0035] 1.75 <N6<1.95;

[0036] 20 <V6<30;

[0037] 0.17 <T6 / L SR <0.21;

[0038] 0.0050 <d4 / L SR <0.0055.

[0039] Further, the focal power of the second lens group is ΦB, the focal length of the seventh lens is F7, the refractive index of the seventh lens is N7, the Abbe number of the seventh lens is V7, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the seventh lens is T7, the distance between the sixth lens and the seventh lens is d5, and the following relationship is satisfied:

[0040] 1.42 <F7 / ΦB<1.65;

[0041] 1.52 <N7<1.65;

[0042] 55 <V7<70;

[0043] 0.015 <T7 / L SR <0.035;

[0044] 0.065 <d5 / L SR <0.083.

[0045] Further, the focal power of the second lens group is ΦB, the focal length of the eighth lens is F8, the refractive index of the eighth lens is N8, the Abbe number of the eighth lens is V8, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the eighth lens is T8, the distance between the seventh lens and the eighth lens is d6, and the following relationship is satisfied:

[0046] 1.30 <F8 / ΦB<1.40;

[0047] 1.45 <N8<1.65;

[0048] 70 <V8<95;

[0049] 0.015 <T8 / L SR <0.035;

[0050] 0.055 <d6 / L SR <0.085.

[0051] Further, the focal power of the second lens group is ΦB, the focal length of the ninth lens is F9, the refractive index of the ninth lens is N9, the Abbe number of the ninth lens is V9, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the ninth lens is T9, and satisfies the following relationship:

[0052] -3.20 <F9 / ΦB<-2.55;

[0053] 1.55 <N9<1.75;

[0054] 25 <V9<40;

[0055] 0.12 <T9 / L SR <0.17.

[0056] Furthermore, the focal power of the second lens group is ΦB, and the focal length of the tenth lens is F10 , the refractive index of the tenth lens is N 10 , the Abbe number of the tenth lens is V 10 , the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the tenth lens is T 10 , the distance between the ninth lens and the tenth lens is d7, the distance between the tenth lens and the imaging plane is d8, and the following relationship is satisfied:

[0057] 1.01 <F 10 / ΦB<1.25;

[0058] 1.45 <N 10 <1.65;

[0059] 55 <V 10 <72;

[0060] 0.015 <T 10 / L SR <0.035;

[0061] 0.025 <d7 / L SR <0.041;

[0062] -0.30 <d8 / L SR <-0.25.

[0063] Compared with the prior art, the wide-angle astronomical eyepiece according to the embodiment of the present invention has the following beneficial effects:

[0064] The optical power of the six lenses of the first lens group of the embodiment of the present invention is positive, negative, positive, negative, positive, negative, which helps to correct chromatic aberration and spherical aberration, ensure clear imaging and accurate color reproduction, and the optical power of the four lenses of the second lens group is negative, negative, positive, negative, which aims to further optimize the image quality, especially the clarity and distortion control in the edge area. In addition, the first lens and the second lens, the fourth lens and the fifth lens, and the eighth lens and the ninth lens are glued together respectively, which can better control chromatic aberration and thus reduce dispersion. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram of the structure of a wide-angle astronomical eyepiece according to a first embodiment of the present invention:

[0066] Figure 2 is an optical distortion & field curvature diagram of the wide-angle astronomical eyepiece of the first embodiment provided by an embodiment of the present invention;

[0067] Figure 3 is a vertical axis chromatic aberration diagram of the wide-angle astronomical eyepiece of the first embodiment provided by the embodiment of the present invention;

[0068] Figure 4 is a schematic diagram of an interface flange of a wide-angle astronomical eyepiece according to a first embodiment of the present invention;

[0069] Figure 5 This is a schematic diagram of the structure of a wide-angle astronomical eyepiece according to a second embodiment of the present invention:

[0070] Figure 6 is an optical distortion & field curvature diagram of the wide-angle astronomical eyepiece of the second embodiment provided by an embodiment of the present invention;

[0071] Figure 7 is a vertical axis chromatic aberration diagram of the wide-angle astronomical eyepiece of the second embodiment provided by an embodiment of the present invention;

[0072] Figure 8 This is a schematic diagram of the structure of a wide-angle astronomical eyepiece according to a third embodiment of the present invention:

[0073] Fig. 9 is an optical distortion & field curvature diagram of the wide-angle astronomical eyepiece of the third embodiment provided by an embodiment of the present invention;

[0074] Fig.10 is a vertical axis chromatic aberration diagram of the wide-angle astronomical eyepiece of the third embodiment provided by the embodiment of the present invention;

[0075] Fig.11 This is a schematic diagram of the structure of a wide-angle astronomical eyepiece according to a fourth embodiment of the present invention:

[0076] Fig.12 is an optical distortion & field curvature diagram of the wide-angle astronomical eyepiece of the fourth embodiment provided by the embodiment of the present invention;

[0077] Fig.13 is a vertical axis chromatic aberration diagram of the wide-angle astronomical eyepiece of the fourth embodiment provided by the embodiment of the present invention;

[0078] In the figure, L1 is the first lens; L2 is the second lens; L3 is the third lens; L4 is the fourth lens; L5 is the fifth lens; L6 is the sixth lens; L7 is the seventh lens; L8 is the eighth lens; L9 is the ninth lens; and L10 is the tenth lens. DETAILED DESCRIPTION

[0079] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0080] In addition to military sights, for general optical instruments, an exit pupil distance of the eyepiece greater than 15 mm is considered a long exit pupil distance. According to the relationship of geometric triangles, it is difficult for existing astronomical eyepieces to make the outer diameter of the interface less than 2 inches. Moreover, the interfaces of astronomical eyepieces have international standards, usually 1.25 inches and 2 inches. If the interface size does not meet these specifications, it will be difficult to obtain purchases from existing holders of astronomical objectives because their objective interfaces will be difficult to match. For example: a. The relationship among the exit pupil distance, field angle, and system outer diameter is that under the condition of a constant angle, for every 1 mm increase in the exit pupil distance, the outer diameter of the system will increase by at least 2.2 mm. b. The relationship among the focal length, field angle, and imaging circle is that under the condition of a constant angle, the larger the focal length, the larger the imaging circle. Considering the mechanical structure and machining allowance, the lens diameter at the rear end of the 2-inch interface astronomical eyepiece on the flange surface (i.e., 3 mm to the left of the S19 imaging surface) should be less than 44 mm. There is a proportional relationship between a and b, that is, a is proportional to b.

[0081] As Figures 1 to 4 shown, the present invention provides a wide-angle astronomical eyepiece, which sequentially includes a diaphragm, a first lens group, and a second lens group from the object side to the image side. The first lens group sequentially includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6 from the object side to the image side; the second lens group sequentially includes a seventh lens L7, an eighth lens L8, a ninth lens L9, and a tenth lens L10 from the object side to the image side; the first lens L1 has a positive optical power, the second lens L2 has a negative optical power, the third lens L3 has a positive optical power, the fourth lens L4 has a negative optical power, the fifth lens L5 has a positive optical power, the sixth lens L6 has a negative optical power, the seventh lens L7 has a negative optical power, the eighth lens L8 has a negative optical power, the ninth lens L9 has a positive optical power, and the tenth lens L10 has a negative optical power. Moreover, the first lens L1 and the second lens L2 are glued together, the fourth lens L4 and the fifth lens L5 are glued together, and the eighth lens L8 and the ninth lens L9 are glued together; the optical power of the first lens group is ΦF, the focal length of the first lens L1 is F1, the refractive index of the first lens L1 is N1, the Abbe number of the first lens L1 is V1, and the focal length of the sixth lens L6 is F6, and the following relationships are satisfied: 0.42 < F1 / ΦF < 0.65 to ensure the wide-angle characteristics of the eyepiece and good focal length control, and avoid excessive aberration; 1.70 < N1 < 1.85, which helps for a more compact design and better aberration control; 35 < V1 < 65 to ensure that the refractive index change under different colors (wavelengths) is relatively small, which helps to reduce chromatic aberration; -0.028 < F6 / ΦF < -0.021, which helps to adjust the aberration balance of the entire eyepiece system, especially field curvature and distortion.

[0082] The optical power of the six lenses of the first lens group of this embodiment is positive, negative, positive, negative, positive, negative, which helps to correct chromatic aberration and spherical aberration, ensure clear imaging and accurate color reproduction, and the optical power of the four lenses of the second lens group is negative, negative, positive, negative, which aims to further optimize the image quality, especially the clarity and distortion control in the edge area. In addition, the first lens L1 and the second lens L2, the fourth lens L4 and the fifth lens L5, and the eighth lens L8 and the ninth lens L9 are glued together respectively, which can better control chromatic aberration and thus reduce dispersion.

[0083] It should be noted that the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9 and the tenth lens L10 form an optical system. The first lens L1 is made of lanthanum crown glass, which has extremely high hardness and extremely low abrasion. It is placed as the first lens in the optical system to provide good protection and is suitable for various climatic environments encountered during field observation. In addition, the high refractive index material of the first lens L1 deflects the large-angle parallel light entering from the S1 surface by a larger angle so that the outer diameter of the entire optical system is not too large.

[0084] It should also be noted that, in the drawings, S1 is an aperture, S2 is the object-side surface of the first lens L1, S3 is the image-side surface of the first lens L1 (also the object-side surface of the second lens L2), S4 is the image-side surface of the second lens L2, S5 is the object-side surface of the third lens L3, S6 is the image-side surface of the third lens L3, S7 is the object-side surface of the fourth lens L4, S8 is the image-side surface of the fourth lens L4 (also the object-side surface of the fifth lens L5), and S9 is the image-side surface of the fifth lens L5. S10 is the object-side surface of the sixth lens L6, S11 is the image-side surface of the sixth lens L6, S12 is the object-side surface of the seventh lens L7, S13 is the image-side surface of the seventh lens L7, S14 is the object-side surface of the eighth lens L8, S15 is the image-side surface of the eighth lens L8 (also the object-side surface of the ninth lens L9), S16 is the image-side surface of the ninth lens L9, S17 is the object-side surface of the tenth lens L10, S18 is the image-side surface of the tenth lens L10, and S19 is an imaging surface.

[0085] Furthermore, the focal length of the second lens L2 is F2, the refractive index of the second lens L2 is N2, the Abbe number of the second lens L2 is V2, and the distance between the aperture and the focal plane of the first lens group is L SR, the thickness of the second lens L2 is T2, and the following relational expressions are satisfied: -0.35 < F2 / ΦF < -0.20, which helps to control the light path and contributes to correcting aberrations such as coma and field curvature, ensuring the image quality across the entire field of view; 1.85 < N2 < 2.00, which helps to reduce the lens size and weight; 17 < V2 < 35, which is set in combination with the above Abbe number to offset chromatic aberration and achieve chromatic aberration correction; 0.015 < T2 / L SR <0.035, to optimize the path of light passing through the eyepiece, ensure that the light is correctly focused and reduce unnecessary light scattering or absorption, thereby improving the overall image sharpness and contrast.

[0086] The thickness of the first lens L1 in this embodiment is T1, and the distance between the aperture stop and the first lens L1 is d1, and the following relational expressions are satisfied: 0.15 < T1 / L SR <0.20, which can ensure that when the first lens L1 receives and initially bends the light entering the system, it can effectively control these aberrations, thereby improving the imaging quality of the entire system, 0.18 < d1 / L SR <0.23, which can optimize the angle of light entering the first lens L1, reduce the skew effect of marginal rays, thereby reducing aberrations and ensuring the image quality across the entire field of view.

[0087] Furthermore, the focal length of the third lens L3 is F3, the refractive index of the third lens L3 is N3, the Abbe number of the third lens L3 is V3, and the distance between the aperture stop and the focal plane of the first lens group is L SR , the thickness of the third lens L3 is T3, and the distance between the second lens L2 and the third lens L3 is d2, and the following relational expressions are satisfied: 0.25 < F3 / ΦF < 0.4, which is set in combination with other lenses to optimize the aberration correction of the entire system; 1.7 < N3 < 1.95, which can balance the optical performance and manufacturing cost, and at the same time helps to control dispersion and aberrations, ensuring the image quality; 45 < V3 < 65, which is beneficial to reducing chromatic aberration; 0.14 < T3 / L SR <0.18, to ensure the correct refraction of light when passing through the lens; 0.0050 < d2 / L SR <0.0055, ensure that no additional aberrations are introduced when light propagates between the two lenses. The third lens L3 further converges the light of the large-angle field of view, further reducing the outer diameter of the optical system.

[0088] Furthermore, the focal length of the fourth lens L4 is F4, the refractive index of the fourth lens L4 is N4, the Abbe number of the fourth lens L4 is V4, and the distance between the aperture stop and the focal plane of the first lens group is L SR, the thickness of the fourth lens L4 is T4, the distance between the third lens L3 and the fourth lens L4 is d3, and the following relationships are satisfied: -0.21 < F4 / ΦF < -0.11, which helps correct the aberrations in the system, especially spherical aberration and coma aberration, ensuring that light can be accurately focused after passing through the lens system; 1.75 < N4 < 1.85, which helps achieve a stronger light bending ability while maintaining the lens size; 17 < V4 < 35, which is set in cooperation with other lenses to achieve clear imaging of white light through chromatic aberration correction between lens groups; 0.015 < T4 / L SR <0.035, to ensure that light can be correctly refracted and reflected when passing through, while minimizing any possible optical path interference or loss; 0.0050 < d3 / L SR <0.0055, to ensure that light can be effectively controlled when transmitted between the two lenses, avoid the generation of additional aberrations, and at the same time ensure the compactness and efficiency of the entire system.

[0089] Furthermore, the focal length of the fifth lens L5 is F5, the refractive index of the fifth lens L5 is N5, the Abbe number of the fifth lens L5 is V5, and the distance between the aperture stop and the focal plane of the first lens group is L SR , the thickness of the fifth lens L5 is T5, and the following relationships are satisfied: 0.31 < F5 / ΦF < 0.45, which helps balance the optical path in the eyepiece system and at the same time participates in correcting aberrations such as spherical aberration and chromatic aberration to improve the imaging quality of the entire system; 1.7 < N5 < 1.89, which provides good light bending ability while maintaining the compactness of the optical system and reducing weight; 40 < V5 < 60, which helps reduce chromatic aberration; 0.14 < T5 / L SR <0.21, to ensure that light can pass through in an optimized manner while maintaining an appropriate optical path length, which helps control various aberrations and maintain good optical performance.

[0090] Furthermore, the refractive index of the sixth lens L6 is N6, the Abbe number of the sixth lens L6 is V6, and the distance between the aperture stop and the focal plane of the first lens group is L SR , the thickness of the sixth lens L6 is T6, the distance between the fifth lens L5 and the sixth lens L6 is d4, and the following relationships are satisfied: 1.75 < N6 < 1.95, which can bend light more effectively; 20 < V6 < 30, which is combined with lenses with a higher Abbe number to reduce the chromatic aberration of the entire system and ensure the accuracy of imaging colors; 0.17 < T6 / L SR <0.21, to ensure that light can be properly refracted when passing through the lens, while minimizing the scattering of light inside the lens and maintaining the clarity and contrast of the image; 0.0050 < d4 / L SR< 0.0055 ensures precise control of the distance between the two lenses, which helps optimize the light propagation path between the lenses, reduce aberration, and thus improve the imaging quality of the entire system. In addition, the sixth lens L6 can lower the height of the subsequent propagated light, providing a role in the implementation of the 2-inch interface.

[0091] The optical path formed by the first lens L1 to the sixth lens L6 in this embodiment bends and converges the parallel light collected by the S1 aperture, reducing the projection height of the light in subsequent propagation.

[0092] Further, the optical power of the second lens group is ΦB, the focal length of the seventh lens L7 is F7, the refractive index of the seventh lens L7 is N7, the Abbe number of the seventh lens L7 is V7, the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the seventh lens L7 is T7, the distance between the sixth lens L6 and the seventh lens L7 is d5, and the following relational expressions are satisfied: 1.42 < F7 / ΦB < 1.65, which helps focus the light and participate in the correction of overall aberration, especially the part related to chromatic aberration and spherical aberration; 1.52 < N7 < 1.65, which can provide good light deflection ability while keeping the lens size and weight reasonable; 55 < V7 < 70, which helps reduce chromatic aberration and ensures that lights of different colors can be focused on the same plane; 0.015 < T7 / L SR < 0.035 to ensure that the light can pass through in the best way while maintaining an appropriate optical path length, which helps control various aberrations; 0.065 < d5 / L SR < 0.083 to ensure that the light can be effectively controlled when transmitted between the two lenses, avoid the generation of additional aberration, and at the same time maintain the compactness and efficiency of the entire system. The seventh lens L7 can further lower the light passing through the sixth lens L6.

[0093] Further, the optical power of the second lens group is ΦB, the focal length of the eighth lens L8 is F8, the refractive index of the eighth lens L8 is N8, the Abbe number of the eighth lens L8 is V8, the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the eighth lens L8 is T8, the distance between the seventh lens L7 and the eighth lens L8 is d6, and the following relational expressions are satisfied: 1.30 < F8 / ΦB < 1.40, which helps focus the light and participate in the correction of aberration; 1.45 < N8 < 1.65, which can balance the size and weight of the lens and at the same time provide good light bending ability, helping to achieve a compact and effective optical design; 70 < V8 < 95, which helps reduce chromatic aberration and ensures that the focal points of lights of different wavelengths are close, thereby improving the image clarity and color fidelity; 0.015 < T8 / L SR< 0.035, to ensure that light can pass through in an optimized manner while controlling various aberrations; 0.055 < d6 / L SR < 0.085, ensuring an accurate spacing between the two lenses, which helps optimize the light propagation path between the lenses, reduce additional aberrations, and maintain the compactness and efficiency of the entire system.

[0094] Furthermore, the optical power of the second lens group is ΦB, the focal length of the ninth lens L9 is F9, the refractive index of the ninth lens L9 is N9, the Abbe number of the ninth lens L9 is V9, and the distance between the aperture stop and the focal plane of the first lens group is L SR , the thickness of the ninth lens L9 is T9, and the following relationships are satisfied: -3.20 < F9 / ΦB < -2.55, which helps correct aberrations in the entire system, especially chromatic aberration and spherical aberration, ensuring image quality from the center to the edge; 1.55 < N9 < 1.75, which can balance optical performance and lens size while providing good light control, contributing to the realization of a compact optical system; 25 < V9 < 40, when combined with lenses having a high Abbe number, it can help correct chromatic aberration, ensuring that light of different colors is focused at the same point and improving image clarity and color fidelity; 0.12 < T9 / L SR < 0.17, to ensure that light can pass through the lens in the most effective way while controlling aberrations and maintaining image quality.

[0095] Furthermore, the optical power of the second lens group is ΦB, the focal length of the tenth lens L10 is F 10 , the refractive index of the tenth lens L10 is N 10 , the Abbe number of the tenth lens L10 is V 10 , the distance between the aperture stop and the focal plane of the first lens group is L SR , the thickness of the tenth lens L10 is T 10 , the distance between the ninth lens L9 and the tenth lens L10 is d7, the distance between the tenth lens L10 and the imaging surface is d8, and the following relationships are satisfied: 1.01 < F 10 / ΦB < 1.25, which helps light focus and is involved in correcting aberrations in the system; 1.45 < N 10 < 1.65, which can provide good light control ability while contributing to maintaining the compactness and light weight of the lens; 55 < V 10 < 72, which helps reduce chromatic aberration, ensuring that light of different wavelengths can be focused at nearby points; 0.015 < T 10 / L SR < 0.035, to ensure that light can pass through in an optimized manner while controlling various aberrations; 0.025 < d7 / L SR<0.041, ensuring a suitable spacing between the two lenses, which helps optimize the light propagation path between the lenses, reduces additional aberrations, and maintains the compactness and efficiency of the entire system; -0.30 <d8 / L SR <-0.25 to ensure that the light can be focused in the correct plane to form a clear image, while taking into account the exit pupil distance and eye point position to provide users with comfortable observation conditions.

[0096] It should be noted that, in this embodiment, the curvature radius R of the second surface S18 of the tenth lens L10 corresponding to 1 / R should be always greater than 0 (the positive and negative signs are defined as the curvature radius is negative when it bends toward the S1 stop surface, and positive when it is opposite), so as to better reduce the diameters of the lenses from the seventh lens L7 to the tenth lens L10.

[0097] The wide-angle astronomical eyepiece of the present invention will be described below with examples. The units of the spherical radius and the lens spacing are mm.

[0098] Combination Figures 1 to 3 , Table 1 shows the design data of the wide-angle astronomical eyepiece according to the first embodiment of the present invention.

[0099]

Table 1

[0100]

[0101]

[0102] The total optical focal length Φ of the system in this embodiment is 0.04, the object numerical aperture NA is 0.11, the total length is defined as the system length from S1 to S18 is 132.7 mm, the DFOV is 100°, the imaging circle diameter is D39.2 mm, and the S1-S2 distance is defined as the exit pupil distance of 19.6 mm.

[0103] Figure 2 This is the optical distortion & field curvature diagram of the wide-angle astronomical eyepiece of Example 1. The field curvature of the present invention does not exceed the residual field curvature of three diopters required by the visual optical system. The field curvature of the off-axis meridian and sagittal planes basically coincide, and the imaging quality is good.

[0104] Figure 3 This is the vertical axis chromatic aberration diagram of the wide-angle astronomical eyepiece in Example 1. The maximum vertical axis chromatic aberration is less than 16um. The indicators of this optical system require that the vertical axis chromatic aberration be controlled within a very small range, so that there is no obvious color difference at the edge of the visual image.

[0105] Combination Figures 5 to 7 , Table 2 shows the design data of the wide-angle astronomical eyepiece according to the second embodiment of the present invention.

[0106]

Table 2

[0107]

[0108]

[0109] The total optical focal length Φ of the system in this embodiment is 0.04; the object numerical aperture NA is 0.11; the total length is defined as the system length from S1 to S18 is 129.1 mm; the DFOV is 100°; the imaging circle diameter is D39.2 mm; and the S1-S2 distance is defined as the exit pupil distance of 19.03 mm.

[0110] Combination Figures 8 to 10 , Table 3 shows the design data of the wide-angle astronomical eyepiece according to the third embodiment of the present invention.

[0111]

Table 3

[0112] Surface serial number Surface type Surface radius Surface interval Nd Vd S1(Aperture) Spherical infinity 18.34 S2 Spherical 490.000 16.00 1.84 45.16 S3 Spherical -35.000 2.00 1.96 17.47 S4 Spherical -58.871 0.30 S5 Spherical 122.761 15.50 1.82 45.16 S6 Spherical -300.500 0.30 S7 Spherical 117.439 3.00 1.67 36.17 S8 Spherical 48.195 16.00 1.82 45.81 S9 Spherical infinity 0.47 S10 Spherical 45.461 12.00 1.96 17.47 S11 Spherical 38.000 8.17 S12 Spherical -118.376 3.00 1.68 62.46 S13 Spherical 31.359 7.80 S14 Spherical -213.670 2.00 1.56 62.61 S15 Spherical 38.150 12.00 2.00 27.43 S16 Spherical -66.280 2.86 S17 Spherical -41.167 3.00 1.54 58.47 S18 Spherical 222.062 -26.01 S19 (imaging surface) Spherical infinity

[0113] The total optical focal length Φ of the system in this embodiment is 0.04, the object numerical aperture NA is 0.11, the total length is defined as the system length from S1 to S18 is 122.5 mm, the DFOV is 100°, the imaging circle diameter is D39.2 mm, and the S1-S2 distance is defined as the exit pupil distance of 18.35 mm.

[0114] Combination Figures 11 to 13 , Table 4 shows the design data of the wide-angle astronomical eyepiece according to the fourth embodiment of the present invention.

[0115]

Table 4

[0116]

[0117]

[0118] The total optical focal length Φ of the system in this embodiment is 0.04, the object numerical aperture NA is 0.11, the total length is defined as the system length from S1 to S18 is 117.8 mm, the DFOV is 100°, the imaging circle diameter is D39.2 mm, and the S1-S2 distance is defined as the exit pupil distance of 15.0 mm.

[0119] In summary, the embodiments of the present invention provide a wide-angle astronomical eyepiece, which allows the incident light to transition smoothly without generating excessive light deviation angles, thereby reducing the sensitivity of the overall light system and maximizing tolerance redundancy, greatly improving the yield of actual production and further reducing costs, so that the observer can achieve a large observation angle, high imaging quality, a long exit pupil distance, and good picture color observation effects under visual conditions. Combined with the large focal length, the deep space field of view is wide, providing a more surrounded experience.

[0120] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A wide-angle astronomical eyepiece, characterized in that: The first lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from the object side to the image side; the second lens group includes a seventh lens, an eighth lens, a ninth lens and a tenth lens from the object side to the image side; The first lens has positive focal power, the second lens has negative focal power, the third lens has positive focal power, the fourth lens has negative focal power, the fifth lens has positive focal power, the sixth lens has negative focal power, the seventh lens has negative focal power, the eighth lens has negative focal power, the ninth lens has positive focal power, the tenth lens has negative focal power, and the first lens is cemented to the second lens, the fourth lens is cemented to the fifth lens, and the eighth lens is cemented to the ninth lens; The focal power of the first lens group is ΦF, the focal length of the first lens is F1, the refractive index of the first lens is N1, the Abbe number of the first lens is V1, the focal length of the sixth lens is F6, and the following relationship is satisfied: 0.42 <F1 / ΦF<0.65; 1.70<N1<1.85； 35<V1<65； -0.028 <F6 / ΦF<-0.021。 2. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal length of the second lens is F2, the refractive index of the second lens is N2, the Abbe number of the second lens is V2, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the second lens is T2, and satisfies the following relationship: -0.35 <F2 / ΦF<-0.20; 1.85<N2<2.00； 17<V2<35； 0.015<T2 / L SR <0.035。 3. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal length of the third lens is F3, the refractive index of the third lens is N3, the Abbe number of the third lens is V3, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the third lens is T3, the distance between the second lens and the third lens is d2, and the following relationship is satisfied: 0.25 <F3 / ΦF<0.4; 1.7<N3<1.95； 45<V3<65； 0.14<T3 / L SR <0.18; 0.0050<d2 / L SR <0.0055。 4. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal length of the fourth lens is F4, the refractive index of the fourth lens is N4, the Abbe number of the fourth lens is V4, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the fourth lens is T4, the distance between the third lens and the fourth lens is d3, and the following relationship is satisfied: -0.21 <F4 / ΦF<-0.11; 1.75<N4<1.85； 17<V4<35； 0.015<T4 / L SR <0.035; 0.0050<d3 / L SR <0.0055。 5. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal length of the fifth lens is F5, the refractive index of the fifth lens is N5, the Abbe number of the fifth lens is V5, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the fifth lens is T5, and satisfies the following relationship: 0.31 <F5 / ΦF<0.45; 1.7<N5<1.89； 40<V5<60； 0.14<T5 / L SR <0.21。 6. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The refractive index of the sixth lens is N6, the Abbe number of the sixth lens is V6, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the sixth lens is T6, the distance between the fifth lens and the sixth lens is d4, and the following relationship is satisfied: 1.75<N6<1.95； 20<V6<30； 0.17<T6 / L SR <0.21; 0.0050<d4 / L SR <0.0055。 7. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal power of the second lens group is ΦB, the focal length of the seventh lens is F7, the refractive index of the seventh lens is N7, the Abbe number of the seventh lens is V7, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the seventh lens is T7, the distance between the sixth lens and the seventh lens is d5, and the following relationship is satisfied: 1.42 <F7 / ΦB<1.65; 1.52<N7<1.65； 55<V7<70； 0.015<T7 / L SR <0.035; 0.065<d5 / L SR <0.083。 8. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal power of the second lens group is ΦB, the focal length of the eighth lens is F8, the refractive index of the eighth lens is N8, the Abbe number of the eighth lens is V8, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the eighth lens is T8, the distance between the seventh lens and the eighth lens is d6, and the following relationship is satisfied: 1.30 <F8 / ΦB<1.40; 1.45<N8<1.65； 70<V8<95； 0.015<T8 / L SR <0.035; 0.055<d6 / L SR <0.085。 9. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal power of the second lens group is ΦB, the focal length of the ninth lens is F9, the refractive index of the ninth lens is N9, the Abbe number of the ninth lens is V9, and the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the ninth lens is T9, and satisfies the following relationship: -3.20 <F9 / ΦB<-2.55; 1.55<N9<1.75； 25<V9<40； 0.12<T9 / L SR <0.17。 10. The wide-angle astronomical eyepiece according to claim 1, characterized in that: The focal power of the second lens group is ΦB, and the focal length of the tenth lens is F 10 , the refractive index of the tenth lens is N 10 , the Abbe number of the tenth lens is V 10 , the distance between the aperture and the focal plane of the first lens group is L SR , the thickness of the tenth lens is T 10 , the distance between the ninth lens and the tenth lens is d7, the distance between the tenth lens and the imaging plane is d8, and the following relationship is satisfied: 1.01<F 10 / ΦB<1.25; 1.45<N 10 <1.65； 55<V 10 <72； 0.015<T 10 / L SR <0.035; 0.025<d7 / L SR <0.041; -0.30<d8 / L SR <-0.25。

Images