Turn-back telescope structure based on aspheric surface structure

Abstract

The invention relates to the technical field of telescopes, in particular to a turn-back type telescope structure based on an aspheric surface structure, which comprises a lens barrel, the outer wall of the lens barrel is fixedly connected with a focal barrel, the inner wall of the lens barrel is fixedly connected with a mounting frame, and the inner wall of the mounting frame is fixedly connected with a secondary reflector. The end, away from the mounting frame, of the lens barrel is fixedly connected with a main reflector, and the outer wall of the main reflector is fixedly connected with a fixing barrel, a large-aperture correction lens is omitted, the main reflector is designed to be an aspheric surface to correct aberration, the aspheric mirror can enable light to be more reasonably converged, and the image quality is improved. According to an optical effective surface aspheric formula of a rotational symmetric aspheric surface, an aspheric primary mirror is obtained through a large amount of calculation optimization. The aspheric primary mirror is high in design and processing accuracy, and the aberration such as astigmatism, coma aberration and spherical aberration can be effectively controlled through detection data display, so that the imaging quality of the telescope is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of telescopes, and in particular to a reentrant telescope structure based on an aspherical structure. Background Art

[0002] Telescopes have always been important tools in the field of astronomical observation and long-distance observation. Traditional telescopes are mainly divided into two types: refracting telescopes and reflecting telescopes. Refracting telescopes have the advantages of clear imaging and accurate color reproduction, but as the aperture increases, problems such as severe chromatic aberration and excessively long lens barrels will appear. Although reflecting telescopes do not have chromatic aberration problems and the lens barrel is relatively short, the spherical reflector has aberrations that affect the imaging quality.

[0003] The catadioptric telescope came into being, which combines some advantages of refracting telescope and reflecting telescope, such as large field of view, strong light power, etc., and the volume of the tube is small after the optical path is folded, which is easy to carry, so it is loved by many astronomy enthusiasts. However, the existing catadioptric telescope also has some limitations.

[0004] The most common catadioptric telescopes on the market are the Schmidt and Maksutov. The Schmidt type can eliminate spherical aberration and off-axis aberration, has strong light power, large field of view, and small aberration, and is suitable for taking photos of large areas of the sky, but the corrector is an aspherical lens, which has high production costs and is difficult to process with large apertures. The Maksutov type uses a concave lens as the corrector, and the light is refracted and reflected by it to focus and form an image, but it is also difficult to make a large-aperture product. Summary of the invention

[0005] In view of the shortcomings of the prior art, the technical solution adopted by the present invention to solve the technical problems is: a reentrant telescope structure based on an aspherical structure, comprising: a lens barrel, the outer wall of the lens barrel is fixedly connected to a focal barrel, the inner wall of the lens barrel is fixedly connected to a mounting frame, the inner wall of the mounting frame is fixedly connected to a secondary reflector, the end of the lens barrel away from the mounting frame is fixedly connected to a primary reflector, and the outer wall of the primary reflector is fixedly connected to a fixed barrel. After entering the lens barrel, the light first reaches the primary reflector, and after being reflected by the primary reflector, the light changes its propagation direction and is emitted to the secondary reflector.

[0006] The present invention is further configured such that the inner wall of the fixed tube is fixedly connected with a first lens, the inner wall of the fixed tube is fixedly connected with a second lens, the inner wall of the fixed tube at one end away from the first lens is fixedly connected with a third lens, and the second lens is arranged between the first lens and the third lens. The secondary reflector reflects the light again, so that the light passes through the first lens, the second lens and the third lens in the fixed tube in sequence. Since the primary reflector is an aspherical surface with a large hole in the center, the light passes through the large hole in the center of the primary reflector and is finally focused and imaged at the focal tube.

[0007] The present invention is further configured such that the main reflector is designed as an aspherical surface, and a large hole is opened at the center of the main reflector. By designing the main reflector as an aspherical surface, aberrations are corrected. When a spherical mirror forms an image, aberrations will occur because the incident light rays deflect more strongly as the distance from the optical axis increases and do not meet at the same point, resulting in blurred images. An aspherical mirror can converge light rays more reasonably and improve image quality.

[0008] The present invention is further configured such that the optically effective surface aspheric formula of the rotationally symmetric aspheric surface is:

[0009] in For an aspheric surface at height The height of the arrow relative to the vertex, is the vertical distance from a point on the aspherical surface to the optical axis, is the paraxial curvature radius of the aspheric surface, is the quadratic constant used to describe the shape of the aspheric surface, n is the highest order of the aspheric polynomial, is the aspheric coefficient, n is the coefficient of the polynomial, i is the order of the polynomial, is the power in the aspheric polynomial, According to the aspheric formula of the optical effective surface of the rotationally symmetric aspheric surface, the aspheric primary mirror is obtained through calculation and optimization. The design and processing precision of the aspheric primary mirror is high. Its test data shows that aberrations such as astigmatism, coma, and spherical aberration are effectively controlled, thus ensuring the imaging quality of the telescope.

[0010] The beneficial effects of the present invention are as follows: 1. The present invention adopts a non-spherical design for the main reflector, and a large hole is opened in the center, which can accurately control the light reflection path and effectively reduce aberration. Compared with the traditional spherical reflector, the image is clearer. In application scenarios such as astronomical observation and long-distance observation, it can provide users with more accurate and detailed images, whether observing celestial details or long-distance targets on the ground, etc., better visual effects can be obtained.

[0011] 2. The present invention eliminates the large-aperture correction lens and corrects the aberration by designing the main reflector as an aspherical surface. The aspherical mirror can make the light converge more reasonably and improve the image quality. According to the aspherical formula of the optical effective surface of the rotationally symmetrical aspherical surface, the aspherical primary mirror is obtained after a large number of calculations and optimizations. The design and processing accuracy of the aspherical primary mirror is high. Its detection data shows that aberrations such as astigmatism, coma, and spherical aberration are effectively controlled, thereby ensuring the imaging quality of the telescope.

[0012] 3. The telescope of the present invention only includes two reflectors and three small lenses. This structure is simple and reasonable. The setting of the small lenses further refracts and adjusts the light, and works in conjunction with the aspherical main reflector. While ensuring image quality, it avoids the problem of difficulty in processing large-aperture lenses and realizes high-precision astronomical observation and photography functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the internal structure of the present invention; Figure 3 It is a schematic diagram of the structure of the main reflector of the present invention; Figure 4 It is a schematic diagram of the fixed cylinder structure of the present invention; Figure 5 is an optical reflection graph of the present invention; Figure 6 It is the Seidel aberration detection table of the present invention.

[0014] In the figure: 1, lens barrel; 2, focal barrel; 3, mounting frame; 4, secondary reflector; 5, fixed barrel; 6, primary reflector; 7, first lens; 8, second lens; 9, third lens. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses. Example

[0016] See also Figure 1 - Figure 5 The present invention provides a technical solution: a reentrant telescope structure based on an aspherical structure, comprising: a lens barrel 1, a focal barrel 2 is fixedly connected to the outer wall of the lens barrel 1, a mounting frame 3 is fixedly connected to the inner wall of the lens barrel 1, a secondary reflector 4 is fixedly connected to the inner wall of the mounting frame 3, a main reflector 6 is fixedly connected to the end of the lens barrel 1 away from the mounting frame 3, and a fixing barrel 5 is fixedly connected to the outer wall of the main reflector 6.

[0017] A first lens 7 is fixedly connected to the inner wall of the fixed tube 5 , a second lens 8 is fixedly connected to the inner wall of the fixed tube 5 , a third lens 9 is fixedly connected to the inner wall of one end of the fixed tube 5 away from the first lens 7 , and the second lens 8 is arranged between the first lens 7 and the third lens 9 .

[0018] The main reflector 6 is of aspherical design, and a large hole is opened at the center of the main reflector 6 .

[0019] The optical effective surface aspheric formula of the rotationally symmetric aspheric surface is:

[0020] in For an aspheric surface at height The height of the arrow relative to the vertex, is the vertical distance from a point on the aspherical surface to the optical axis, is the paraxial curvature radius of the aspheric surface, is the quadratic constant used to describe the shape of the aspheric surface, n is the highest order of the aspheric polynomial, is the aspheric coefficient, n is the coefficient of the polynomial, i is the order of the polynomial, is the power in the aspheric polynomial, .

[0021] Working principle: When in use, after the light enters the lens barrel 1, it first reaches the primary reflector 6. After being reflected by the primary reflector 6, the light changes its propagation direction and is directed to the secondary reflector 4. The secondary reflector 4 reflects the light again, so that the light passes through the first lens 7, the second lens 8 and the third lens 9 in the fixed barrel 5 in sequence. Since the primary reflector 6 is an aspherical surface with a large hole in the center, the light passes through the large hole in the center of the primary reflector 6 and is finally focused and imaged at the focal barrel 2. In traditional catadioptric telescopes, it is difficult to process large-aperture correction lenses. The present invention eliminates large-aperture correction lenses and corrects aberrations by designing the primary reflector as an aspherical surface. When a spherical mirror forms an image, aberrations will occur because the incident light rays deflect more strongly as the distance from the optical axis increases and do not meet at the same point, resulting in blurred images. An aspherical mirror can converge light rays more reasonably and improve image quality. Based on the aspherical formula of the optical effective surface of a rotationally symmetrical aspherical surface, an aspherical primary mirror is obtained through calculation and optimization. The design and processing accuracy of the aspherical primary mirror is high, and its detection data shows that aberrations such as astigmatism, coma, and spherical aberration are effectively controlled, thereby ensuring the imaging quality of the telescope.

[0022] In the Seidel aberration detection of the main reflector of this telescope, several key items are covered. The tilt value is 0.617λ and the clock direction is 20.649°, which reflects the angular deviation of the main reflector in space. Too large deviation will cause the light to deviate from the ideal propagation path and affect the accuracy of the imaging position. The focus value is 0.189λ, which represents the degree of focus. Deviation from the ideal value will cause image blur, which directly affects the image clarity and shape fidelity. Astigmatism will cause light in different directions to focus on different planes, making the image partially blurred; coma makes the image of off-axis objects appear comet-shaped; spherical aberration causes the light to not converge at one point, causing the overall image to be blurred. These aberration indicators comprehensively reflect the main reflector's ability to control light and the imaging quality; PV and RMS are key indicators for measuring aberrations, which refer to the optical path difference between the maximum peak and the minimum valley of the wave surface, and intuitively show the maximum fluctuation range of the aberration. The PV value of the present invention is 0.166λ, and the RMS value is 0.043λ, which is obtained by calculating the root mean square of the wave surface error, and more comprehensively reflects the overall distribution of aberrations. In this telescope, these two values ​​are relatively low, indicating that the aberration of the main reflector is effectively controlled, and the aspherical design is effective in correcting aberrations, which can meet the requirements of high-precision astronomical observation and photography.

[0023] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A reentrant telescope structure based on an aspherical structure, characterized in that: include: A lens barrel (1), wherein the outer wall of the lens barrel (1) is fixedly connected to a focal barrel (2), the inner wall of the lens barrel (1) is fixedly connected to a mounting frame (3), the inner wall of the mounting frame (3) is fixedly connected to a secondary reflector (4), an end of the lens barrel (1) away from the mounting frame (3) is fixedly connected to a primary reflector (6), and the outer wall of the primary reflector (6) is fixedly connected to a fixing barrel (5).

2. The reentrant telescope structure based on an aspherical structure according to claim 1, characterized in that: A first lens (7) is fixedly connected to the inner wall of the fixed cylinder (5), a second lens (8) is fixedly connected to the inner wall of the fixed cylinder (5), a third lens (9) is fixedly connected to the inner wall of an end of the fixed cylinder (5) away from the first lens (7), and the second lens (8) is arranged between the first lens (7) and the third lens (9).

3. The reentrant telescope structure based on an aspherical structure according to claim 1, characterized in that: The main reflector (6) is of aspherical design, and a large hole is provided at the center of the main reflector (6).

4. The reentrant telescope structure based on an aspherical structure according to claim 1, characterized in that: The optical effective surface aspheric formula of the rotationally symmetric aspheric surface is: in For an aspheric surface at height The height of the arrow relative to the vertex, is the vertical distance from a point on the aspherical surface to the optical axis, is the paraxial curvature radius of the aspheric surface, is the quadratic constant used to describe the shape of the aspheric surface, n is the highest order of the aspheric polynomial, is the aspheric coefficient, n is the coefficient of the polynomial, i is the order of the polynomial, is the power in the aspheric polynomial, .

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