A wide-angle astronomical eyepiece

Abstract

The present invention discloses a wide-angle astronomical eyepiece, which includes an aperture stop, a first lens group and a second lens group. The first lens group sequentially 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 sequentially 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 and the second lens, the fourth lens and the fifth lens, and the eighth lens and the ninth lens are respectively adhesively disposed; the optical 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 relational expressions are satisfied: 0.42 < F1 / ΦF < 0.65; 1.70 < N1 < 1.85; 35 < V1 < 65; -0.028 < F6 / ΦF < -0.021. The wide-angle astronomical eyepiece of the present invention can better control chromatic aberration, thereby reducing the dispersion phenomenon.

Description

Technical Field

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

[0002] With improved living standards and a growing passion for exploring nature, outdoor activities, especially astronomical observation, have become a popular pastime. Traditional ground-based landscape observations are no longer able to satisfy modern people's growing curiosity and pursuit of the ultimate experience. As a result, deep-space astronomical observation has gradually become a new focus. However, despite the increasing use of large deep-space telescopes, the eyepieces used with them have certain limitations.

[0003] The common deep-space astronomical telescope eyepieces on the market currently have the problem of a small angle and a large focal length, or a small angle and a small focal length. They have a simple structure, incomplete chromatic aberration correction, a short exit pupil distance, and a cramped visual experience, and can only achieve the effect of just seeing. Summary of the Invention

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

[0005] To solve the above technical problems, the present invention provides a wide-angle astronomical eyepiece comprising, from the object side to the image side, an aperture, a first lens group, and a second lens group. The first lens group comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The second lens group comprises, from the object side to the image side, a seventh lens, an eighth lens, a ninth lens, and a tenth lens.

[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, and the tenth lens has negative focal power, and the first lens and the second lens are cemented together, the fourth lens and the fifth lens are cemented together, and the eighth lens and the ninth lens are cemented together;

[0007] The optical 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, and 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] Furthermore, the optical 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] Furthermore, the optical 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] Furthermore, 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 optical 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 advantages:

[0064] The six lenses in the first lens group of this embodiment have a power sequence of positive, negative, positive, negative, positive, and negative, respectively, which helps correct chromatic and spherical aberrations, ensuring sharp images and accurate color reproduction. The four lenses in the second lens group have a power sequence of negative, negative, positive, and negative, further optimizing image quality, particularly sharpness and distortion control in peripheral areas. Furthermore, the first and second lenses, the fourth and fifth lenses, and the eighth and ninth lenses are cemented together to better control chromatic aberration and 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 This is a diagram showing optical distortion and field curvature of the wide-angle astronomical eyepiece according to the first embodiment of the present invention;

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

[0068] Figure 4 1 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 This is a diagram showing optical distortion and field curvature of the wide-angle astronomical eyepiece according to the second embodiment of the present invention;

[0071] Figure 7 is a vertical axial chromatic aberration diagram of the wide-angle astronomical eyepiece according to the second 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] Figure 9 This is a diagram showing optical distortion and field curvature of the wide-angle astronomical eyepiece according to the third embodiment of the present invention;

[0074] Figure 10 is a diagram of vertical axial chromatic aberration of the wide-angle astronomical eyepiece according to the third embodiment of the present invention;

[0075] Figure 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] Figure 12 1 is an optical distortion and field curvature diagram of the wide-angle astronomical eyepiece according to the fourth embodiment of the present invention;

[0077] Figure 13 is a diagram of vertical axial chromatic aberration of the wide-angle astronomical eyepiece according to the fourth 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 following embodiments of the present invention are described in further detail with reference to 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. The interface of astronomical eyepieces has international standards, usually 1.25 inches and 2 inches. If the interface size is not made to this specification, 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 diameter of the lens 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 an aperture stop, 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, the tenth lens L10 has a negative optical power, and the first lens L1 and the second lens L2 are adhesively bonded, the fourth lens L4 and the fifth lens L5 are adhesively bonded, and the eighth lens L8 and the ninth lens L9 are adhesively bonded; 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, 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 powers of the six lenses in the first lens group of this embodiment are arranged in the order of positive, negative, positive, negative, positive, and negative, helping to correct chromatic and spherical aberrations, ensuring sharp images and accurate color reproduction. The optical powers of the four lenses in the second lens group are arranged in the order of negative, negative, positive, and negative, further optimizing image quality, particularly in the peripheral areas for clarity and distortion control. Furthermore, the first lens L1 is cemented to the second lens L2, the fourth lens L4 is cemented to the fifth lens L5, and the eighth lens L8 is cemented to the ninth lens L9, further controlling chromatic aberration and thus reducing chromatic aberration.

[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. First lens L1 is made of lanthanide crown glass, which has extremely high hardness and extremely low abrasion resistance. Placed as the first lens in the optical system, it provides excellent protection and is suitable for the various climatic conditions encountered during field observation. In addition, the high refractive index material of first lens L1 deflects large-angle parallel light rays entering from the S1 plane by a large angle, thereby reducing the outer diameter of the entire optical system.

[0084] It should also be noted that, in the drawings, S1 is the 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 (which is 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 the 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, to ensure the image quality across the entire field of view; 1.85 < N2 < 2.00, which helps to reduce the size and weight of the lens; 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 clarity 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 to ensure 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 and further reduces 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 to 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 to 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;​​​​​​​​​​​​​​​​​​​< 0.0055 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 reduce the projection height of the subsequent propagated light, which plays 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 the 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 aberrations, and at the same time maintain the compactness and efficiency of the entire system. The seventh lens L7 can further reduce 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 aberrations; 1.45 < N8 < 1.65, which can balance the size and weight of the lens while providing 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 clarity and color fidelity of the image; 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 propagation path of light 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 relational expressions are satisfied: -3.20 < F9 / ΦB < -2.55, which helps correct aberrations in the entire system, especially chromatic aberration and spherical aberration, and ensures 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, helping to achieve a compact optical system; 25 < V9 < 40, when combined with lenses with a high Abbe number, it can help correct chromatic aberration and ensure that light of different colors is focused at the same point, 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 relational expressions are satisfied: 1.01 < F 10 / ΦB < 1.25, which helps light focus while participating in correcting aberrations in the system; 1.45 < N 10 < 1.65, which can provide good light control ability while helping to maintain the compactness and light weight of the lens; 55 < V 10 < 72, which helps reduce chromatic aberration and ensures 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, helping to optimize the light propagation path between the lenses, reducing additional aberrations, and maintaining the compactness and efficiency of the entire system; -0.30 <d8 / L SR <-0.25 to ensure that 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 the curvature radius R of the second surface S18 of the tenth lens L10 of this embodiment, corresponding to 1 / R, should be constantly greater than 0 (the sign of the curvature radius is defined as negative when it curves toward the stop surface S1 and positive when it curves away from the stop surface S1) to further reduce the diameter 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 using an example. The units of the spherical radius and the lens spacing are mm.

[0098] Combine 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 power Φ of the system in this embodiment is 0.04, the object-side numerical aperture NA is 0.11, the total length 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 and field curvature diagram of the wide-angle astronomical eyepiece of Example 1. The field curvature of the present invention does not exceed the three diopters of residual field curvature 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 16μm. 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] Combine 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-side numerical aperture NA is 0.11; the total length is defined as the system length from S1 to S18, which 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, which is 19.03 mm.

[0110] Combine 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 surface infinity 18.34 S2 spherical surface 490.000 16.00 1.84 45.16 S3 spherical surface -35.000 2.00 1.96 17.47 S4 spherical surface -58.871 0.30 S5 spherical surface 122.761 15.50 1.82 45.16 S6 spherical surface -300.500 0.30 S7 spherical surface 117.439 3.00 1.67 36.17 S8 spherical surface 48.195 16.00 1.82 45.81 S9 spherical surface infinity 0.47 S10 spherical surface 45.461 12.00 1.96 17.47 S11 spherical surface 38.000 8.17 S12 spherical surface -118.376 3.00 1.68 62.46 S13 spherical surface 31.359 7.80 S14 spherical surface -213.670 2.00 1.56 62.61 S15 spherical surface 38.150 12.00 2.00 27.43 S16 spherical surface -66.280 2.86 S17 spherical surface -41.167 3.00 1.54 58.47 S18 spherical surface 222.062 -26.01 S19 (imaging surface) spherical surface infinity

[0113] The total optical power Φ of the system in this embodiment is 0.04, the object-side numerical aperture NA is 0.11, the total length 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] Combine 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 power Φ of the system in this embodiment is 0.04, the object-side numerical aperture NA is 0.11, the total length 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 distance S1 to S2 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, resulting in low sensitivity of the overall light system and large 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, and the experience is more surrounded by the scene.

[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 consists of six lenses, including, from the object side to the image side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group. The second lens group consists of four lenses, including, from the object side to the image side, a seventh lens group, an eighth lens group, a ninth lens group, and a tenth lens group. 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, and the tenth lens has negative focal power, and the first lens and the second lens are cemented together, the fourth lens and the fifth lens are cemented together, and the eighth lens and the ninth lens are cemented together; The optical 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, and 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 optical 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 optical 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 optical 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 optical 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。

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