JP2021517279A - Meniscus Cassegrain lens - Google Patents

Abstract

The present invention relates to a Meniscus Cassegrain lens, and more particularly to a Meniscus Cassegrain lens which is an objective lens that can be used in a telescope and includes a solid lens in which an incident surface, a primary mirror and a secondary mirror are all formed in a spherical shape. .. According to the present invention, there are advantages that the resolution is visually high, the resolution is high, and a wide field of view can be provided while reducing off-axis aberrations. In addition, the lens is coated with a reflective material and protected to form a primary mirror and a secondary mirror, which prevents the penetration and contamination of other foreign substances and eliminates the need for periodic recoating. The mirror can be held semi-permanently, which is convenient for management and use.

Description

The present invention relates to a Meniscus Cassegrain lens, and more specifically, a Meniscus including an objective lens that can be used for a telescope or a telephoto lens, and includes a solid lens in which an incident surface, a primary mirror, and a secondary mirror are all formed in a spherical shape. Regarding Cassegrain lenses.

The present invention relates to an objective lens or an objective optical system used in a telescope, and more specifically to a catadioptric telescope.

A reflecting and refracting telescope is a telescope made by using a lens and a mirror, and is made by combining the advantages of a refracting telescope that provides a stable image and the advantages of a reflecting telescope that has good focusing power. In the reflecting and refracting telescope, the main optical system is the reflecting telescope, but in order to remove the coma that appears in the reflecting telescope, a spherical primary mirror, a spherical secondary mirror, and a spherical aberration correction lens are used. Typical examples of the catadioptric telescope are the Maxtofuka Cassegrain type and the Schmidt Cassegrain type.

However, the Maksutov-Cassegrain type or Schmidt Cassegrain type catadioptric telescope requires a correction lens and / or a correction plate, and has a problem that the lens barrel is large and complicated, and the manufacturing cost is high.

As a reflection / refraction type objective lens, a catadioptric lens having a spherical incident surface, a secondary mirror, and a primary mirror has been invented prior to the present invention (Japanese Patent Laid-Open No. 11-316343). , It was developed not for telescopes like the present invention, but for ultra-compact imaging.
According to claim 2 of this patent
[Japanese Patent Laid-Open No. 11-316343-Claim 2]
The catadioptric lens according to claim 1, wherein the incident surface is formed so as to satisfy the following conditions.
0.5 << | ra / f | <1
(However, ra: radius of curvature of the incident surface, f: focal length of the entire system)

The range of its (monolens) -refractive objectives is very restrictive.

At this time, the term 0.5 << ra / f | <1 (ra: radius of curvature of the incident surface, f: focal length of the entire system) means that the focal length of the entire system is more than 1 times the radius of curvature of the incident surface. In the sense that it is longer and less than twice as long, this value is formed so that the center of curvature of the secondary mirror and the primary mirror are different when the curvature of the incident surface and the secondary mirror are the same. It is a | ra / f | numerical value that appears only when the plane of incidence and the center of curvature of the secondary mirror are located in front of the center of curvature of the primary mirror.

On the other hand, the basic meniscus Cassegrain lens of the present invention described below is designed so that the primary mirror, the secondary mirror, and the incident surface have the same center of curvature. And the radius of curvature ra of the secondary mirror becomes shorter, and the focal point is reflected farther due to the increase in the curvature of the secondary mirror, so that the focal length f becomes longer and two kinds of simultaneous differences occur, and | ra / f | < 0.5 is common. That is, the back focal length of the lens exceeds twice the radius of curvature of the incident surface.

After all, the | ra / f | value of the basic meniscus Cassegrain lens of the present invention in which 0 << ra / f | <0.5 is generally established and the | ra / f | value of JP-A-11-316343 are There is a large numerical deviation.

Further, as a typical example of the basic meniscus Cassegrain lens of the present invention, when the refractive index of the lens medium is 1.47 and the radius of curvature of the incident surface is 2 ×, the focal length (Back focal length) is 7. Since it exceeds ×, | ra / f | <0.3 is established. In addition, it becomes a relatively slim catadioptric objective lens in which the thickness of the lens is only half the width of the primary mirror.

Therefore, it can be confirmed that there is a large difference from the category of catadioptric lenses (0.5 << ra / f | <1) published in Japanese Patent Application Laid-Open No. 11-316343.

To explain it in an extended manner, the basic meniscus casegren lens of the present invention described below has a ratio of a natural number in which the ratio of the lens thickness to the incident surface and the radius of curvature of the secondary mirror to the radius of curvature of the primary mirror is 1: 2: 3. It is possible to make an objective lens and a slim objective lens in which the thickness of the lens is only half the width of the primary mirror. However, in the category of the catadioptric lens of JP-A-11-316343, such an objective is used. The lens can never be constructed.

Since a telescope for real vision requires a large amount of light and a large aperture, a large amount of transparent solid material for the lens is required, which is not economical. The catadioptric lens published in JP-A-11-316343 is not suitable as an objective lens for a telescope for actual vision.

The present inventor compensates for the above-mentioned disadvantages of various conventional catadioptric objective lenses and the Maxto-Cassegrain type or Schmidt Cassegrain type reflection refracting telescope, and can produce a slim product with low light loss and high resolution. The present invention has been completed after many years of research efforts to develop a refracting objective lens for a telescope that is easy to perform precision processing.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a reflection / refraction objective lens having low light loss, high resolution, and easy manufacturing and precision processing. And.

In order to solve the above object, the basic meniscus casegren lens according to the present invention is composed of a basic solid lens, and an incident surface for refracting and passing light is formed in the peripheral portion of the front surface of the basic solid lens. A primary mirror that reflects light that has passed through the incident surface is provided around the rear surface of the basic solid lens, and light reflected by the primary mirror is reflected at the center of the front surface of the basic solid lens. A secondary mirror that focuses and re-reflects is provided, and an exit surface through which the light re-reflected by the secondary mirror passes is formed at the center of the rear surface of the basic solid lens, and the incident surface, the primary mirror, and the primary mirror are formed. The secondary mirrors are all concave spherical surfaces when viewed from the front, and are characterized in that the incident surface, the secondary mirror, and the center of curvature of the primary mirror are the same with respect to the optical axis of the basic solid lens.

Here, the curvature of the incident surface is set so that the virtual eccentricity of the primary mirror is formed between 0 and 1 with reference to the light incident parallel to the incident surface. It is a feature.

Here, the secondary mirror and the primary mirror are characterized in that the front surface and the rear surface of the basic solid lens are coated with a reflective material to be protected.

Here, the center of curvature of the secondary mirror and the primary mirror is the same with respect to the optical axis of the basic solid lens.

Here, the exit surface is characterized in that it is formed on a concave spherical surface when viewed from the rear so that the light rereflected by the secondary mirror passes vertically through the exit surface.

Here, in order to correct the chromatic aberration of the light, a chromatic aberration correction lens is further included behind the exit surface.

On the other hand, the integrated meniscus casegren lens according to the present invention includes an integrated solid lens and a focusing lens arranged in front of the integrated solid lens, and the integrated solid lens and the focusing lens are the above-mentioned basic solids. The lens is characterized in that the incident surface of the basic solid lens is separated forward and is formed independently of the negative meniscus lens, and the focusing lens is configured to be movable forward and backward.

Here, when the focusing lens and the integrated solid lens are closest to each other, the center of curvature of the rear surface of the focusing lens and the center of curvature of the incident surface of the integrated solid lens are the same.

Here, when the focusing lens and the integrated solid lens are closest to each other, the outermost light passes through the front surface of the focusing lens and is refracted with reference to the optical axis of the focusing lens, and is in front of the focusing lens. The light that has passed through the direction and is refracted is vertically emitted from the rear surface of the focusing lens, and the light that is vertically emitted from the rear surface of the focusing lens is vertically incident on the incident surface of the integrated solid lens. The feature is that the curvature of the rear surface of the focusing lens and the incident surface of the integrated solid lens is formed so that the light incident vertically on the incident surface of the solid lens reaches the outermost outer shell of the primary mirror. To do.

In the basic meniscus Cassegrain lens according to an embodiment of the present invention, the incident surface, the primary mirror and the secondary mirror are all formed on a spherical surface, so that not only is it very simple and easy to manufacture, but it can also be precisely processed. it can.

In addition, a reflective material is coated on the lens to protect it to form a primary mirror and a secondary mirror, and only one solid medium exists between the primary mirror and the secondary mirror, so that other foreign substances can penetrate or contaminate the lens. It has the advantage of being able to hold a fresh mirror semi-permanently without the need to be prevented and periodically recoated.

On the other hand, in the integrated Meniscus Cassegrain lens according to another embodiment of the present invention, the focusing lens can be moved forward and backward in front of the solid lens, so that the focus on the field of view due to the change in the distance between the object and the lens. Can be adjusted.

Furthermore, when a telescope is manufactured using the Meniscus Cassegrain lens according to the present invention, the length of the lens barrel can be made shorter than that of a conventional telescope having the same amount of light input.

It is the structural cross-sectional view of the basic type meniscus Cassegrain lens according to one Example of this invention, and the development view which showed precisely the light progress of a lens. It is a structural sectional view which showed various examples of the basic form meniscus Cassegrain lens of this invention. It is a structural cross-sectional view of the integrated meniscus Cassegrain lens according to another embodiment of this invention, and the conceptual diagram which showed the anteroposterior movement of a focusing lens. It is an example figure of the telescope which can be formed using the meniscus Cassegrain lens of this invention, and the 3D figure of the meniscus Cassegrain lens.

The present invention relates to an objective lens that can be used for a telescope or a telephoto lens, and the basic meniscus Cassegrain lens according to the first embodiment and the integrated meniscus Cassegrain lens according to the second embodiment will be described separately below.

<Example 1>: Basic meniscus Cassegrain lens FIG. 1 shows a structural cross-sectional view of a basic meniscus Cassegrain lens according to an embodiment of the present invention and a developed view showing the progress of light of the lens precisely. The basic meniscus Cassegrain lens 10 (hereinafter referred to as "basic lens 10") of the present invention comprises a basic solid lens 100 (hereinafter referred to as "solid lens 100").

As shown, the solid lens 100 is formed in the shape of a meniscus lens.

In the basic lens 10 according to the present invention, the solid lens 100 is composed of a front surface 110 and a rear surface 120, and here, with reference to the drawing, the front is on the left side of the solid lens 100, and the object to be observed is located. This means the side where the light emitted from the object enters the solid lens 100, the rear side is the right side of the solid lens 100, and the rear side means the side where the light exits the solid lens 100.

As shown in FIG. 1, the solid lens 100 can be divided into a central portion C and a peripheral portion S with reference to the optical axis XX'of the solid lens 100. Here, the central portion C and the peripheral portion S do not necessarily mean the same region, and the central portion C is formed in a circle from the center of the front surface 110 of the solid lens with reference to the optical axis XX'. The peripheral portion S means a fixed region, and the peripheral portion S means the remaining peripheral region excluding the fixed region formed circularly from the center on the rear surface 120 of the solid lens 100.

An incident surface 113 that refracts and passes light is formed on the peripheral portion S of the front surface 110, and a primary mirror 127 that reflects light that has passed through the incident surface 113 is provided on the peripheral portion S of the rear surface 120. The central portion C of the direction 110 is provided with a secondary mirror 117 that focuses and rereflects the light reflected by the primary mirror 127, and the central portion C of the rear surface 120 passes the light rereflected by the secondary mirror. An exit surface 123 is formed.

At this time, in the present invention, the incident surface 113, the primary mirror 117, and the secondary mirror 127 are all formed into a concave spherical surface when viewed from the front. More specifically, in each of the incident surface 113, the primary mirror 117 and the secondary mirror 127, the center of curvature of the spherical surface is located in front of each incident surface 113, the primary mirror 117 and the secondary mirror 127, and the optical axis X-of the solid lens 100. It is formed so as to be located on X'.

The principle of the basic lens 10 of the present invention will be described with reference to FIG. 1.

The present invention is a Cassegrain objective lens in which the object to be observed is located in front of the solid lens 100, and the observer can observe the object behind the solid lens 100.

The light emitted from the object travels toward the solid lens 100, passes through the incident surface 113 of the solid lens 100, and is refracted.

Since the incident surface is a concave spherical surface, light is diffusely refracted with respect to the optical axis XX'while passing through the incident surface 113 and is incident on the primary mirror 127.

Since the primary mirror 127 corresponds to a concave spherical mirror, the light incident on the primary mirror 127 is reflected by the primary mirror 127 toward the secondary mirror 117 and incident on the secondary mirror 117.

Since the secondary mirror 117 has a concave spherical surface, it becomes a convex spherical mirror with reference to the traveling direction of the light incident on the secondary mirror 117. Therefore, the light incident on the secondary mirror 117 is focused and re-reflected by the secondary mirror 117.

At this time, since the focal point of the secondary mirror 117 is generally outside the exit surface 123, the light rereflected by the secondary mirror 117 passes through the exit surface 123 and is focused on the focal point, and the observer finally focuses on it. The object can be observed at the position of.

FIG. 2 is a structural cross-sectional view showing various examples of the basic meniscus Cassegrain lens of the present invention.

As shown in FIG. 2A, the exit surface 123 of the solid lens 100 according to the present invention has the exit surface 123 rearward so that the light rereflected by the secondary mirror 117 passes vertically through the exit surface 123. When viewed, it can be formed into a concave spherical surface.

Further, as shown in FIG. 2B, a chromatic aberration correction lens 300 may be further included behind the exit surface 123 in order to correct the chromatic aberration of light. The chromatic aberration correction lens can be composed of two or more overlapping lenses, and is not limited to this.

In general, in an objective lens, forming an exit surface on a convex spherical surface with reference to the traveling direction of light or further including a chromatic aberration correction lens 300 for correcting chromatic aberration belongs to a normal technique, and therefore, the specifics thereof. Contents are omitted.

As described above, in the solid lens 100 of the present invention, the incident surface 113, the primary mirror 127, and the secondary mirror 117 are all formed on a spherical surface, so that the solid lens 100 is not only very simple and easy to manufacture, but also precise. Can be processed into.

Further, in the present invention, since the solid lens 100 is composed of one lens, only one solid medium forming the solid lens 100 exists between the primary mirror 127 and the secondary mirror 117, thereby reducing the loss of light. Can be small.

On the other hand, the secondary mirror 117 and the primary mirror 127 of the present invention can be formed by coating the front surface 110 and the rear surface 120 with a reflective material and protecting them, respectively. That is, the central portion C of the front surface 110 of the solid lens 100 is coated with a reflective material and protected to form the secondary mirror 117, and the peripheral portion S of the rear surface 120 of the solid lens 100 is reflective. The material can be coated and protected to form the primary mirror 127. Here, the protective treatment is used in a mangin mirror, which is the primary mirror of a conventional Cassegrain telescope, by applying a special chemical treatment such as coating a reflective material and applying it to the back surface with amalgam or paint. It is a concept similar to the protective treatment to be performed.

In this way, the front surface 110 and the rear surface 120 are coated with a reflective material and protected to form the secondary mirror 117 and the primary mirror 127, whereby the secondary mirror 117 and the primary mirror 127 of the present invention can be manufactured. Not only is it easy, it prevents foreign matter from penetrating and contaminating, and does not require periodic recoating, allowing a fresh mirror to be held semi-permanently.

On the other hand, the specific design principle of the present invention will be described below.

First, in the present invention, the secondary mirror 117 is formed on a spherical surface.

Generally, in the Cassegrain series orthodox reflecting telescope, the secondary mirror is formed on a hyperboloid and the primary mirror is formed on a paraboloid.

However, the hyperboloid has the disadvantage that it is more difficult to process than the spherical surface, so when trying to make the secondary mirror a spherical surface that is easy to process, the primary mirror must not be formed on a paraboloid, and the modified Dall-Kircam Like the (Dall-Kerkhham) Cassegrain telescope, the primary mirror needs to be formed on an oblong ellipsoid.

Second, in the present invention, the primary mirror 127 is also formed on a spherical surface.

If the secondary and primary mirrors of the Cassegrain telescope are all spherical, it is necessary to position the spherical aberration correction lens and / or the correction plate forward, as in the Maksutov Cassegrain telescope.

Due to the spherical aberration correction lens, the actual eccentricity (of the cross section) of the primary mirror is 0 on the Maxtovka Segren telescope, but the virtual eccentricity of the primary mirror is 0 and the eccentricity is 1. It is formed between the object surface. That is, the virtual eccentricity A of the primary mirror is formed between 0 <A <1, the eccentricity A is formed on the oblong ellipsoid, and the primary mirror is formed on the virtual ellipsoid.

Third, in the present invention, the incident surface 113 is also formed on a spherical surface.

As described in the second section, in a reflecting telescope in which the primary mirror and the secondary mirror are spherical, it is necessary that a spherical aberration correction lens and / or a correction plate is positioned in front of the telescope to refract light.

Since the present invention attempts to use a spherical secondary mirror and a spherical primary mirror in the process of solidifying the Maksutov casegren optical system into one objective lens, it substitutes the role of the correction lens or the correction plate (that is, the spherical aberration correction function). It is necessary to be able to.

This can be derived from the optical principle of the mangin mirror.

The mangin mirror has a negative meniscus lens-like back surface reflective coating on the back surface.

In a mangin mirror, when the front surface, which is the incident surface, and the rear surface, which is the reflecting surface, are all formed into a spherical surface, the curvature of the incident surface is used to focus the light incident in parallel with the incident surface facing one focus. Is formed larger than the curvature of the reflecting surface (that is, the radius of curvature of the incident surface is formed smaller than the radius of curvature of the reflecting surface).

Since the light incident parallel to the incident surface of the Mangin mirror is refracted at the incident surface, the actual (cross-sectional) decentering factor of the reflecting surface is a spherical surface, but the virtual (ideal) decentering of the reflecting surface. The rate is formed on a paraboloid of 1. As a result, the light reflected from the reflecting surface is focused on one focal point in front of the incident surface while vertically passing through the incident surface in front without refraction.

On the other hand, when the incident surface of the mangin mirror is not a spherical surface but a plane having a curvature of 0, the virtual eccentricity of the reflecting surface is 0, and it is actually formed on the same spherical surface as the eccentricity of 0.

Assuming that the curvature of the incident surface when the virtual paraboloid of the reflecting surface of the Mangin mirror becomes a virtual paraboloid of 1, the curvature of the incident surface is formed between 0 and B in the Mangin mirror. In this case, the virtual decentering ratio of the reflecting surface is formed between the spherical surface of 0 and the paraboloid of 1. In other words, when the curvature of the incident surface is formed between 0 and B in the mangin mirror, if the virtual eccentricity of the reflecting surface is X, the virtual eccentricity X of the reflecting surface is 0 <X < It can be seen that the reflective surface is formed at 1, thereby forming a virtual oblong elliptical surface with a virtual eccentricity X.

The table below summarizes this.

In consideration of the above-mentioned contents, the present invention appropriately adjusts the curvature of the incident surface 113 to make a spherical primary mirror 127 like a correction lens or a correction plate in a Maksutov Cassegrain telescope into a virtual ellipsoidal ellipsoid. It can play a role of correcting the surface (that is, a spherical aberration correction function).

Specifically, the present invention sets the curvature of the incident surface 113 so that the virtual eccentricity of the primary mirror 127 is formed between 0 and 1 with reference to the light incident parallel to the incident surface 113. be able to.

Further, the following items should be additionally considered when manufacturing the basic lens 10 according to the present invention.

The virtual eccentricity of the primary mirror 127 can exist innumerably between 0 and 1, and the curvature of the incident surface 113 should be made correspondingly.

At this time, not only the curvature of the primary mirror 127 and the incident surface 113, but also the distance between the incident surface 113 and the primary mirror 127, the refractive index of the medium forming the solid lens 100, and the like are taken into consideration. Need to be properly adjusted so that light can pass through the exit surface 123 and be focused on the focal point formed behind the exit surface 123.

Further, in the present invention, the incident surface 113, the secondary mirror 117, and the center of curvature of the primary mirror 127 are all formed in the same manner with respect to the optical axis XX'of the solid lens. In this case, it is obvious that the radius of curvature and the curvature of the incident surface 113 and the secondary mirror 117 are formed in the same manner.

In this way, when the incident surface 113, the secondary mirror 117, and the center of curvature of the primary mirror 127 are similarly formed with reference to the optical axis XX'of the solid lens 100, a plurality of parallel light rays entering the solid lens 100 are emitted. When reflected by the primary mirror 127 and the secondary mirror 117, the symmetry can be maintained continuously, and the off-axis aberration can be effectively reduced.

In addition, it is visually high because it maintains symmetry continuously when a plurality of lights coming from various angles with the center of curvature on the optical axis XX'are reflected by the primary mirror 127 and the secondary mirror 117. It has a resolution, is high in resolution, and can provide a wide field of view while reducing off-axis aberrations.

As an example of the refractive index of the basic meniscus Cassegrain lens,
When the refractive index of the lens medium is 1.47, the ratio of the thickness on the lens axis to the incident surface and the radius of curvature of the secondary mirror to the radius of curvature of the primary mirror has a ratio of natural numbers of 1: 2: 3, respectively. In this case, the parallel rays incident within the incident angle of 25 degrees of the basic Menis cascadene lens are emitted through the primary mirror and the secondary mirror, and then focused on one point at a point about 7 times the lens thickness.

In this way, the thickness of the lens becomes a slim basic meniscus Cassegrain lens that is only half the width of the primary mirror, and this is an example that belongs to the category of the basic meniscus Cassegrain lens.

On the other hand, in the present invention, the diameter of the secondary mirror 117 may occupy about 60% of the diameter of the incident surface 110, and the secondary mirror 117 may be formed so as to have an area of 33% of the incident surface area.

In the present invention, the solid lens 100 substantially reflects the light rays from the primary mirror around the outside of the secondary mirror, and uses only half the diameter of the secondary mirror. Therefore, the optical axis is set in order to save the solid medium. The central part of the solid lens to be located can be dug out in a columnar shape, and the shape of the solid lens 100 can be cast from the initial stage of production into a shape in which a hole is formed in the primary mirror of a general reflection type telescope.

Assuming that the diameter of the objective lens of the conventional refracting astronomical telescope is 100 mm, in order for the solid lens of the present invention to have the same light input amount as that of the conventional telescope, the solid lens 100 of the present invention The diameter of the front surface 113 needs to be formed to be about 125 mm. The present invention can have the same amount of light input only when the diameter of the front surface 113 is about 125%.

However, although the length is shorter than that of the conventional refracting telescope, the light is reflected twice inside the solid lens 100. Therefore, when a telescope is manufactured using this, the conventional refracting telescope having the same light input light is used. It can be formed shorter than a refracting telescope.

Further, as compared with the conventional reflecting telescope, since the structure of the lens barrel portion is compressed by one objective lens, that is, the solid lens 100, the bulk can be remarkably reduced, thereby utilizing this. When making a telescope, the startability can be increased.

The basic lens 10 as described above is optimized when the light incident on the incident surface 113 of the solid lens 100 is incident on a parallel straight line from an object on the infinite field focal point, for example, for an astronomical object. It can be used as an objective lens for telescopes.

<Example 2>: Integrated meniscus Cassegrain lens The following describes the integrated meniscus Cassegrain lens 20 (hereinafter referred to as “integrated lens 20”) according to another embodiment of the present invention.

In the integrated lens 20 of the present invention, in the above-mentioned basic lens 10, the incident surface 113 of the solid lens 100 is separated forward to be independent as a thin negative meniscus lens, and the focusing lens 200 and the integrated solid lens 100'(, respectively. Hereinafter referred to as "solid lens 100'") is formed, and the focusing lens 200 moves in front of the solid lens 100'to perform the spherical aberration correction function and at the same time to act as a field focus adjustment lens. It was designed in.

Assuming that the incident surface 113 of the solid lens 100 only fulfills the spherical aberration correction function in the basic lens 10 described above, the focusing lens 200 also serves as a spherical aberration correction function and a field focus adjustment lens in the integrated lens 20. be able to.

As described above, the basic lens 10 of the present invention can be adapted to, for example, an astronomical telescope, but since the solid lens 100 is composed of one lens, the distance between the object and the solid lens 100 It is not possible to adjust the focus with a large deviation between them.

Therefore, although the principle of the basic lens 10 is used, the above problem can be solved by adding one lens to adjust the focus of the field of view.

FIG. 3 is a structural cross-sectional view of the integrated meniscus Cassegrain lens according to another embodiment of the present invention, and a conceptual diagram showing the anterior-posterior movement of the focusing lens in the integrated meniscus Cassegrain lens of the present invention. The Meniscus Cassegrain lens 20 can consist of a focusing lens 200 and a solid lens 100'.

As shown, the solid lens 100'and the focusing lens 200 are all formed in the shape of a meniscus lens.

The solid lens 100'is composed of a front surface 110'and a rear surface 120', an incident surface 113'is formed on the front surface 110', and a secondary mirror 117' is provided on the rear surface 120'. A primary mirror 127'is provided and an exit surface 123' is formed.

Here, the configurations of the remaining secondary mirror 117', the primary mirror 127', and the exit surface 123'excluding the incident surface 113'are substantially the same as the corresponding configurations of the basic solid lens 100 described above, and thus are detailed. The description is omitted.

On the other hand, in the focusing lens 200, the incident surface 113 is formed by being independently separated from the front of the basic solid lens 100, and the front surface 210 of the focusing lens 200 is an optical feature of the incident surface 113 of the basic solid lens 100. Can be formed so that can be expressed as well. That is, the curvature and the center of curvature of the front surface 210 of the focusing lens 200 can be formed in the same manner as the curvature and the center of curvature of the incident surface 113 of the basic solid lens 100. It can be formed to be expressed.

The front surface 210 and the rear surface 220 of the focusing lens 200 are all formed into a concave spherical surface when viewed from the front, and the focusing lens 200 is configured to be movable forward and backward on the optical axis XX'.

The principle of the integrated meniscus Cassegrain lens 20 according to the present invention will be described as follows.

The light emitted from the object travels toward the focusing lens 200, is incident on the front surface 210 of the focusing lens 200 and is refracted, and the refracted light passes through the rear surface 220 of the focusing lens 200 and is passed through the solid lens 100. The process of being incident on the incident surface 113'and then passing through the solid lens 100' is the same as that of the basic solid lens 100 described above.

Here, since the front surface 210 of the focusing lens 200 is a concave spherical surface when viewed from the front, light is diffusely refracted with reference to the optical axis XX'through the front surface 210 and exits the rear surface 220.

In the present invention, as shown in FIG. 3, when the focusing lens 200 is separated from the solid lens 100', the outermost light from the optical axis XX' is perpendicular to the incident surface 113'of the solid lens 100'. It is configured to pass.

Further, as shown in FIG. 3, in the present invention, when the focusing lens 200 is in close contact with the solid lens 100'to the maximum extent, the outermost light from the optical axis XX'is the rear surface 220 of the focusing lens 200. The curvature of the rear surface 220 of the focusing lens 200 and the incident surface 113'of the solid lens 100 is set so as to vertically pass through the incident surface 113'of the solid lens 100'.

More specifically, in the case of an infinite field focal point, that is, when the focusing lens 200 and the solid lens 100'are closest to each other, the outermost light with respect to the optical axis XX'is the front surface of the focusing lens 200. The light that has passed through 210 and is refracted and is vertically emitted from the rear surface 220 of the focusing lens 200 and vertically emitted from the rear surface 220 of the focusing lens 200 is vertically incident on the incident surface 113'of the solid lens 100'. The curvature of the rear surface 220 of the focusing lens 200 and the incident surface 113'of the solid lens 100'is such that the light vertically incident on the incident surface 113' of the solid lens 100' reaches the outermost outer shell of the primary lens 127'. Can be formed.

Here, the difference between the radius of curvature and the curvature of the rear surface 220 of the focusing lens 200 and the incident surface 113'of the solid lens 100'is only the difference to the extent that the focusing lens 200 and the solid lens 100'are in close contact with each other, and the present invention is infinite. In the case of a large field focus, it is preferable that the focusing lens 200 and the solid lens 100'are formed in a similarly overlapped form so that the focusing lens 200 and the solid lens 100'are in close contact with each other at a fine distance.

Further, the present invention is in the case of an infinite field focal point, that is, when the object is very far from the lens 20 and the light is incident on the front surface 210 of the focusing lens 200 horizontally with respect to the optical axis XX'. The focusing lens 200 and the solid lens 100'are configured so as to be in close contact with each other to the maximum extent. At this time, the center of curvature of the rear surface 220 of the focusing lens 200 and the center of curvature of the incident surface 113'of the solid lens 100'are formed to be the same. Can be done.

Here, as described above for the basic lens 10, in the integrated lens 20, the exit surface 123'of the solid lens 100'is formed on a concave spherical surface when viewed from the rear, or chromatic aberration is corrected behind the exit surface 123'. The lens 300 for use can be further included.

On the other hand, as shown in FIG. 3, the focusing lens 200 of the present invention is formed so as to be movable forward and backward on the optical axis XX'.

When the focusing lens 200 is moved forward, the forward angle of the light incident on the front surface 210 of the focusing lens 200 can be adjusted. Thereby, the degree of refraction can be adjusted when light is incident on the front surface 210 of the focusing lens 200 and refracted.

That is, the integrated lens 20 moves the focusing lens 200 forward (that is, separates the focusing lens 200 from the solid lens 100') when the object is close to the lens 20, and the object is far from the lens 20. The focusing lens 200 is moved backward (that is, the focusing lens 200 and the solid lens 100'are brought into close contact with each other), and even if the distance between the lens 20 and the object is not constant, the focusing lens 200 is moved forward and backward to view the field. Since the focus of the lens can be adjusted, the function of the objective lens and the focus adjustment lens of a general telescope can be combined.

FIG. 4 is an example view of a telescope that can be formed by using the Meniscus Cassegrain lens of the present invention, and the telescope can be manufactured by using the basic lens 10 or the integrated lens 20 described above. it can.

As described above, the present invention has been described with limited examples and drawings, but the present invention is not limited to the above-mentioned examples, and this is a person who has ordinary knowledge in the field to which the present invention belongs. If so, it goes without saying that various modifications and modifications can be made from such a description. Therefore, the technical idea of the present invention should be grasped only by the claims, and any equivalent or equivalent modification thereof should belong to the category of the technical idea of the present invention.

Claims (4)

Consists of a basic solid lens
The curvature of the incident surface is set so that the virtual eccentricity of the primary mirror is formed between 0 and 1 with reference to the light incident parallel to the incident surface.
An incident surface is formed around the front surface of the basic solid lens to refract and pass light.
A primary mirror that reflects light that has passed through the incident surface is provided around the rear surface of the basic solid lens.
A secondary mirror that focuses and re-reflects the light reflected by the primary mirror is provided at the center of the front surface of the basic solid lens.
An exit surface through which the light rereflected by the secondary mirror passes is formed in the central portion of the rear surface of the basic solid lens.
The incident surface, primary mirror and secondary mirror are all concave spherical surfaces when viewed from the front.
A basic meniscus Cassegrain lens characterized in that the incident surface, the secondary mirror, and the center of curvature of the primary mirror are the same with respect to the optical axis of the basic solid lens. The integrated meniscus Cassegrain lens is
The entrance and exit surfaces of the focusing lens, the entrance surface of the integrated solid lens, and the primary and secondary mirrors are all concave spherical surfaces when viewed from the front.
It is characterized in that the centers of curvature of the secondary mirror and the primary mirror are the same with respect to the optical axis of the integrated solid lens.
The basic meniscus Cassegrain lens is formed by separating the incident surface that corrects the spherical aberration of the primary mirror forward and making it independent as a negative meniscus lens.
An integrated meniscus Cassegrain lens characterized in that a focusing lens having a spherical aberration correction function on the incident surface is configured to be movable forward and backward. The second aspect of claim 2, wherein when the focusing lens and the integrated solid lens are closest to each other, the center of curvature of the exit surface of the focusing lens and the center of curvature of the incident surface of the integrated solid lens are the same. Integrated Menis Cass Kasegren lens. When the focusing lens and the integrated solid lens are closest to each other, the outermost light passes through the incident surface of the focusing lens and is refracted with respect to the optical axis of the focusing lens, and passes through the incident surface of the focusing lens. The refracted light is emitted vertically from the exit surface of the focusing lens.
Light emitted vertically from the exit surface of the focusing lens vertically enters the incident surface of the integrated solid lens.
The feature is that the curvatures of the exit surface of the focusing lens and the incident surface of the integrated solid lens are formed so that the light incident vertically on the incident surface of the solid lens reaches the outermost outer shell of the primary mirror. The integrated meniscus case Glen lens according to claim 2.

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