A large field of view telescope optical system

Abstract

The invention belongs to the technical field of telescope manufacturing, and discloses a telescope optical system with a large field of view. The optical system is characterized in that: an objective lens first lens, an objective lens cemented lens, a focusing lens, an Abbe prism group, an eyepiece cemented lens, an eyepiece third lens, and an eyepiece fourth lens are sequentially arranged along the optical axis direction from the object side to the image side, the objective lens first lens is a plano-convex lens, with a convex surface facing the object side and a flat surface facing the image side, the objective lens cemented lens is formed by cementing an objective lens second lens and an objective lens third lens, the objective lens second lens is a biconvex lens, the objective lens third lens is a biconcave lens, the focusing lens is a convex-concave lens, with a convex surface facing the object side, the eyepiece cemented lens is formed by cementing an eyepiece first lens and an eyepiece second lens, the eyepiece first lens is a biconcave lens, the eyepiece second lens is a biconvex lens, the eyepiece third lens is a biconvex lens, the eyepiece fourth lens is a biconvex lens, and the field of view is 6.9°.

Description

Technical Field

[0001] The invention relates to the technical field of telescope manufacturing, in particular to a large-field-of-view telescope optical system. Background Art

[0002] A telescope is an optical instrument that uses lenses, reflectors and other optical devices to observe distant objects. The principle is that the light is refracted through the lens or reflected by the concave mirror so that it enters the small hole and converges into an image, and then is seen through a magnifying eyepiece. It is also called a "telescope". The telescope has multiple functions, including magnifying the angle of distant objects so that the human eye can see details with smaller angular distances, and sending the light beam collected by the objective lens that is much thicker than the pupil diameter into the human eye, so that the observer can see dim objects that were originally invisible. There are many types of telescopes, including astronomical telescopes, binoculars, etc.

[0003] The field of view of binoculars refers to the range of the sky that can be observed, usually expressed in angles. The larger the field of view, the wider the observation range. The field of view is an important parameter of binoculars. It determines the field of view that the telescope can observe. Generally speaking, the larger the aperture, the more light enters, and the brighter the observed image. Currently, the field of view of many telescope optical systems is designed to be very small, and the objects observed are very blurry. Summary of the invention

[0004] The object of the present invention is to provide a large-field-of-view telescope optical system to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a large field of view telescope optical system, characterized in that: an objective lens first lens, an objective lens cemented lens, a focusing lens, an Abbe prism group, an eyepiece cemented lens, an eyepiece third lens, an eyepiece fourth lens are arranged in sequence from the object side to the image side along the optical axis direction.

[0006] The first lens of the objective lens is a plano-convex lens, with the convex surface facing the object side and the flat surface facing the image side. The objective lens cemented lens is formed by cementing the second lens of the objective lens and the third lens of the objective lens. The second lens of the objective lens is a biconvex lens, the third lens of the objective lens is a biconcave lens, and the focusing lens is a convex-concave lens, with the convex surface facing the object side.

[0007] The eyepiece cemented lens is formed by cementing the first eyepiece lens and the second eyepiece lens. The first eyepiece lens is a biconcave lens, the second eyepiece lens is a biconvex lens, the third eyepiece lens is a biconvex lens, and the fourth eyepiece lens is a biconvex lens.

[0008] As an optimal technical solution, the object side curvature radius of the first lens of the objective lens is 128.7mm, the image side is a plane, the center thickness is 7mm, the material is glass H-K9L, and the diameter is 57mm; the object side curvature radius of the second lens of the objective lens is 69.7mm, the image side curvature radius is -336.7mm, the center thickness is 9.5mm, the material is glass H-K9L, and the diameter is 54mm; the object side curvature radius of the third lens of the objective lens is -336.7mm, the image side curvature radius is 336.7mm, the center thickness is 4mm, the material is glass H-ZF7LA, and the diameter is 54mm; the object side curvature radius of the focusing lens is 87.9mm, the image side curvature radius is 45.19mm, the center thickness is 3mm, the material is glass H-K9L, and the diameter is 31mm;

[0009] The object side curvature radius of the first lens of the eyepiece is -381mm, the image side curvature radius is 22.97mm, the center thickness is 2.2mm, the material is glass H-ZF7LA, and the diameter is 29mm; the object side curvature radius of the second lens of the eyepiece is 22.97mm, the image side curvature radius is -28.95mm, the center thickness is 11.5mm, the material is glass H-K9L, and the diameter is 29mm; the object side curvature radius of the third lens of the eyepiece is 39.4mm, the image side curvature radius is -115.1mm, the center thickness is 5.6mm, the material is glass H-K9L, and the diameter is 30mm; the object side curvature radius of the fourth lens of the eyepiece is 25.37mm, the image side curvature radius is -268.6mm, the center thickness is 6.5mm, the material is glass H-K9L, and the diameter is 29mm.

[0010] As a preferred technical solution, the distance between the first lens and the second lens of the objective lens along the optical axis is 0.7 mm, the distance between the third lens of the objective lens and the focusing lens is 40.5 mm, the distance between the focusing lens and the object side of the Abbe prism group is 25.5 mm, the distance between the image side of the Abbe prism group and the first lens of the eyepiece is 15.48 mm, the distance between the second lens and the third lens of the eyepiece is 0.2 mm, and the distance between the third lens and the fourth lens of the eyepiece is 0.2 mm.

[0011] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0012] The telescope optical system of the present application has a magnification of 8.5, an exit pupil diameter of 6.4 mm, an exit pupil distance of 20.3 mm, a field of view of 6.9°, an objective first lens, an objective cemented lens, and a focusing lens constitute an objective lens group, and the focal length of the objective lens group is 178.3 mm; an eyepiece cemented lens, an eyepiece third lens, and an eyepiece fourth lens constitute an eyepiece group, and the focal length of the eyepiece group is 21.2 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0014] Figure 1 is a schematic diagram of an optical system of the present invention;

[0015] Figure 2 is a field curvature distortion diagram of the present invention;

[0016] Figure 3 is a spot diagram of the present invention;

[0017] Figure 4 It is a color difference diagram of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] As attached Figure 1-3 As shown, the present invention provides the following technical solution: a large field of view telescope optical system, characterized in that: an objective first lens 1, an objective cemented lens 2, a focusing lens 3, an Abbe prism group 4, an eyepiece cemented lens 5, an eyepiece third lens 6, an eyepiece fourth lens 7 are sequentially arranged from the object side to the image side along the optical axis direction,

[0020] The first lens 1 of the objective lens is a plano-convex lens, with the convex surface facing the object side and the flat surface facing the image side. The objective lens cemented lens 2 is formed by cementing the second lens 2a of the objective lens and the third lens 2b of the objective lens. The second lens 2a of the objective lens is a biconvex lens, and the third lens 2b of the objective lens is a biconcave lens. The focusing lens 3 is a convex-concave lens, with the convex surface facing the object side.

[0021] The eyepiece cemented lens 5 is formed by cementing the first eyepiece lens 5a and the second eyepiece lens 5b. The first eyepiece lens 5a is a biconcave lens, the second eyepiece lens 5b is a biconvex lens, the third eyepiece lens 6 is a biconvex lens, and the fourth eyepiece lens 7 is a biconvex lens.

[0022] As an optimal technical solution, the object side curvature radius of the first lens 1 of the objective lens is 128.7mm, the image side is a plane, the center thickness is 7mm, the material is glass H-K9L, and the diameter is 57mm; the object side curvature radius of the second lens 2a of the objective lens is 69.7mm, the image side curvature radius is -336.7mm, the center thickness is 9.5mm, the material is glass H-K9L, and the diameter is 54mm; the object side curvature radius of the third lens 2b of the objective lens is -336.7mm, the image side curvature radius is 336.7mm, the center thickness is 4mm, the material is glass H-ZF7LA, and the diameter is 54mm; the object side curvature radius of the focusing lens 3 is 87.9mm, the image side curvature radius is 45.19mm, the center thickness is 3mm, the material is glass H-K9L, and the diameter is 31mm;

[0023] The object side curvature radius of the first lens 5a of the eyepiece is -381mm, the image side curvature radius is 22.97mm, the center thickness is 2.2mm, the material is glass H-ZF7LA, and the diameter is 29mm; the object side curvature radius of the second lens 5b of the eyepiece is 22.97mm, the image side curvature radius is -28.95mm, the center thickness is 11.5mm, the material is glass H-K9L, and the diameter is 29mm; the object side curvature radius of the third lens 6 of the eyepiece is 39.4mm, the image side curvature radius is -115.1mm, the center thickness is 5.6mm, the material is glass H-K9L, and the diameter is 30mm; the object side curvature radius of the fourth lens 7 of the eyepiece is 25.37mm, the image side curvature radius is -268.6mm, the center thickness is 6.5mm, the material is glass H-K9L, and the diameter is 29mm.

[0024] As a preferred technical solution, the distance between the first lens 1 and the second lens 2a of the objective lens along the optical axis is 0.7 mm, the distance between the third lens 2b of the objective lens and the focusing lens 3 is 40.5 mm, the distance between the focusing lens 3 and the object side of the Abbe prism group 4 is 25.5 mm, the distance between the image side of the Abbe prism group 4 and the first lens 5a of the eyepiece is 15.48 mm, the distance between the second lens 5b of the eyepiece and the third lens 6 of the eyepiece is 0.2 mm, and the distance between the third lens 6 of the eyepiece and the fourth lens 7 of the eyepiece is 0.2 mm.

[0025] The telescope optical system of the present invention has a magnification of 8.5, an exit pupil diameter of 6.4 mm, an exit pupil distance of 20.3 mm, a field of view of 6.9°, an objective first lens 1, an objective cemented lens 2, and a focusing lens 3 form an objective lens group, the focal length of the objective lens group is 178.3 mm, an eyepiece cemented lens 5, an eyepiece third lens 6, and an eyepiece fourth lens 7 form an eyepiece group, the focal length of the eyepiece group is 21.2 mm, the object side optical axis length of the Abbe prism group 4 is 48.31 mm, the right side optical axis length of the Abbe prism group 4 is 40 mm, the focusing lens 3 moves 10 mm toward the image side, corresponding to a minimum focusing distance of 2.8 m, and the focusing lens moves 2 mm toward the image side, corresponding to a low-magnification infinity of 6.8 diopter.

[0026] The present application uses an Abbe prism group 4. As a total reflection prism, the Abbe prism group 4 can bring higher light transmittance, so that optical instruments such as telescopes can obtain brighter and clearer images when used.

[0027] Attached Figure 2 The field curvature distortion diagram of this application is an important tool for evaluating the imaging quality of optical systems. It reveals the influence of field curvature and distortion on imaging effects. It is also called field curvature. It describes that after a plane object passes through a lens system, the clear image points formed are not on a plane, but on a curved surface. Distortion reflects the similarity between the object and the image, including barrel distortion and pincushion distortion. We use the attached Figure 2 It can be seen that the field curvature of the present application is very small, the edges and the center are relatively clear, the image quality is good, the distortion is less than 5%, and the human eye cannot observe the deformation of the image after the telescope forms an image.

[0028] Attached Figure 3 It is the point diagram of the present application. The distribution of points in the point diagram should be uniform and dense, without obvious abnormal values ​​or outliers. The more evenly distributed the data is, the more stable the imaging quality is. The energy of the optical system point diagram in the present application is relatively concentrated, and the imaging is relatively clear.

[0029] Attached Figure 4 It is the chromatic aberration diagram of the present application. The chromatic aberration diagram is a visualization tool for displaying the chromatic aberration phenomenon in the imaging of an optical system. It reveals that since the lens has different refractive indices for light of different wavelengths, the multi-color light is separated after passing through the lens and cannot be focused on the same point, thus causing chromatic aberration on the imaging surface. The optical system of the present application has no obvious chromatic aberration under visible light conditions.

[0030] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A large field of view telescope optical system, characterized in that: An objective lens first lens (1), an objective lens cemented lens (2), a focusing lens (3), an Abbe prism group (4), an eyepiece cemented lens (5), an eyepiece third lens (6), an eyepiece fourth lens (7) are sequentially arranged along the optical axis from the object side to the image side. The first lens (1) of the objective lens is a plano-convex lens, with the convex surface facing the object side and the flat surface facing the image side; the cemented lens (2) of the objective lens is formed by cementing the second lens (2a) of the objective lens and the third lens (2b) of the objective lens; the second lens (2a) of the objective lens is a biconvex lens, the third lens (2b) of the objective lens is a biconcave lens; and the focusing lens (3) is a convex-concave lens, with the convex surface facing the object side; The eyepiece cemented lens (5) is formed by cementing the first eyepiece lens (5a) and the second eyepiece lens (5b), the first eyepiece lens (5a) is a biconcave lens, the second eyepiece lens (5b) is a biconvex lens, the third eyepiece lens (6) is a biconvex lens, and the fourth eyepiece lens (7) is a biconvex lens. The optical system has only the above eight lenses with optical power. The first lens (1) of the objective lens has an object side curvature radius of 128.7 mm, an image side is a plane, a center thickness of 7 mm, is made of glass H-K9L, and has a diameter of 57 mm; the second lens (2a) of the objective lens has an object side curvature radius of 69.7 mm, an image side curvature radius of -336.7 mm, a center thickness of 9.5 mm, is made of glass H-K9L, and has a diameter of 54 mm; the third lens (2b) of the objective lens has an object side curvature radius of -336.7 mm, an image side curvature radius of 336.7 mm, a center thickness of 4 mm, is made of glass H-ZF7LA, and has a diameter of 54 mm; the focusing lens (3) has an object side curvature radius of 87.9 mm, an image side curvature radius of 45.19 mm, a center thickness of 3 mm, is made of glass H-K9L, and has a diameter of 31 mm; The first lens (5a) of the eyepiece has a curvature radius of -381 mm on the object side, a curvature radius of 22.97 mm on the image side, a center thickness of 2.2 mm, and is made of glass H-ZF7LA with a diameter of 29 mm; the second lens (5b) of the eyepiece has a curvature radius of 22.97 mm on the object side, a curvature radius of -28.95 mm on the image side, a center thickness of 11.5 mm, and is made of glass H-K9L with a diameter of 29 mm; the third lens (6) of the eyepiece has a curvature radius of 39.4 mm on the object side, a curvature radius of -115.1 mm on the image side, a center thickness of 5.6 mm, and is made of glass H-K9L with a diameter of 30 mm; the fourth lens (7) of the eyepiece has a curvature radius of 25.37 mm on the object side, a curvature radius of -268.6 mm on the image side, a center thickness of 6.5 mm, and is made of glass H-K9L with a diameter of 29 mm.

2. A large field of view telescope optical system according to claim 1, characterized in that: Along the optical axis direction, the distance between the objective lens first lens (1) and the objective lens second lens (2a) is 0.7 mm, the distance between the objective lens third lens (2b) and the focusing lens (3) is 40.5 mm, the distance between the focusing lens (3) and the object side of the Abbe prism group (4) is 25.5 mm, the distance between the image side of the Abbe prism group (4) and the eyepiece first lens (5a) is 15.48 mm, the distance between the eyepiece second lens (5b) and the eyepiece third lens (6) is 0.2 mm, and the distance between the eyepiece third lens (6) and the eyepiece fourth lens (7) is 0.2 mm.

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