WO2020115996A1

WO2020115996A1 - Optical system including reflecting body and focusing body

Info

Publication number: WO2020115996A1
Application number: PCT/JP2019/037444
Authority: WO
Inventors: 栄治浅利
Original assignee: 栄治浅利
Priority date: 2018-12-03
Filing date: 2019-09-25
Publication date: 2020-06-11
Also published as: JP6602942B1; JP2020091315A

Abstract

Provided is an optical system that has a large focusing power, that can be easily and inexpensively manufactured, and that can be used in a midsize or larger reflecting telescope or the like. The optical system comprises: a reflecting body; one or more focusing bodies; and a light-receiving unit. The reflecting body includes a reflective surface that reflects light radiated by an object and is capable of condensing the reflected light at a linear focal point. The focusing body is disposed between the reflecting body and the linear focal point of the reflecting body and is capable of focusing light at a spot focal point by transmitting the light reflected by the reflecting body. The light-receiving unit is disposed downstream, in the direction of travel of the light transmitted through the focusing body, and is capable of receiving the light transmitted through the focusing body.

Description

Optical system having a reflector and a focusing body

The present invention relates to an optical system used for a reflecting telescope or the like, and more specifically, instead of a mortar-shaped parabolic mirror used for a conventional reflecting telescope, a flat plate curved in only one direction has a concave shape. The present invention relates to an optical system that uses a main mirror having a reflecting surface and combines one or a plurality of columnar lenses with the main mirror, and that can be easily and inexpensively manufactured with a large focusing power.

Many improved reflection telescopes have been developed up to now, including the Newton-type reflection telescope in which a parabolic reflection mirror is used, but the accuracy required for the polishing technology of the parabolic reflection mirror used as the primary mirror has been improved. The height and complexity of its working process remains unchanged to this day. Therefore, the medium-sized and large-sized reflecting telescopes are expensive, and it is almost impossible to manufacture a medium-sized or larger reflecting telescope. Large parabolic reflectors weigh from a few tons to a few tens of tons, so the deformation of the mirror surface due to gravity becomes a problem, and the deformation also depends on the height of the observing body. Therefore, the correction of the deformation of the mirror surface is impossible except for a special state-of-the-art control system such as a Subaru telescope.

　Medium-scale and larger reflecting telescopes are difficult to manufacture unless they are large-scale organizations from the technical and cost perspectives. Therefore, if it is possible to manufacture a reflecting telescope with a large condensing power that requires a huge amount of money at a lower cost, more convenience, and a lighter weight than a conventional telescope, even a general citizen level owns a medium-sized or larger reflecting telescope, You can make your own.

The system described in Patent Document 1 has been proposed as a technique for solving such a problem in medium-sized and large-sized reflecting telescopes. In this system, two concave reflectors are arranged with their concave surfaces facing each other. The light beam emitted from the object is reflected by the first reflector, which is the primary mirror, toward the opposing second reflector. The light ray from the first reflector is reflected by the second reflector. The first reflector and the second reflector are each bent in one direction orthogonal to each other, so that the respective linear foci are merged at the foci. Since this system uses a concave reflector that can be made from a thin sheet metal or the like, rather than using a high-cost parabolic reflector, it is said that it can be constructed lightweight and inexpensively. There is. The applicant of the present application also proposes a compound radiation surface type telescope using the same principle as that of Patent Document 1, as disclosed in Patent Document 2.

Patent Document 3 proposes an optical device in which two columnar lenses are arranged such that their column axes are orthogonal to each other. According to this apparatus, the light can be converged and diverged independently for the two orthogonal components that are perpendicular to the optical axis, so that images with different vertical and horizontal magnifications can be obtained.

JP, 2005-164881, A JP, 2010-15116, A JP-A-57-204018

The optical systems proposed in Patent Document 1 and Patent Document 2 have the following problems.
First, in these optical systems, in order to obtain a final image without distortion, high-precision optics for realizing the calculation result after performing advanced optical calculation as shown in Patent Document 2 It is necessary to build a system. In particular, the shape of the second concave reflector for focusing the light reflected by the first concave reflector on the point focus without distortion is calculated, and the complicated shape of the second concave reflector that matches the calculation result is calculated. It is difficult to manufacture the first reflector and the second reflector with high precision, and neither a telescope that realizes this optical system nor a captured image thereof has been obtained yet.

Next, in order to fabricate a telescope that realizes the principles of these optical systems, the second reflecting mirror having a complicated shape is distorted between the object whose image is to be captured and the first reflecting body. It must be fixed in the hollow so that it does not exist. However, a large-scale and expensive structure is required to fix the second reflecting mirror in the hollow state while stabilizing the optical shape.

Also, with the optical systems of

Patent Documents

1 and 2, it is difficult to place the focal point outside the optical system. In the optical system of Patent Document 1, it is difficult to focus the light on the point focus without tilting the first and second reflectors as described above, but the reflectors are tilted. It is extremely difficult to calculate and design an optical system that realizes distortion-free imaging outside the optical system. In the optical system of Patent Document 2, since it is necessary to provide the first reflector with a path for the light reflected from the second reflector, it is difficult to manufacture and the cost is high.

Further, in the optical systems of Patent Document 1 and Patent Document 2, in the case where a vertical or horizontal distortion occurs in the final image, in order to correct the distortion, the first reflector and the second reflector are used. Since it is necessary to dispose a refracting body between them, the structure of the optical system becomes complicated.

The optical device proposed in Patent Document 3 is said to be able to obtain images with different vertical and horizontal magnifications by using two columnar lenses whose column axes are orthogonal to each other. It is speculated that this optical device can be used for the purpose of broadening the spectrum in either direction, for example. However, if a columnar lens is used as the primary mirror as in this optical device, the weight becomes large when the size of the primary mirror is increased to form an image of a distant object. It is difficult to adopt it in a telescope.

An object of the present invention is to provide an optical system which has a large light-collecting power and can be manufactured easily and inexpensively and which can be used for a medium-sized or larger reflecting telescope or the like.

The present invention provides an optical system. The optical system includes a reflector, one or more focusing bodies, and a light receiving unit. The reflector has a reflecting surface that reflects the light emitted from the object, and can collect the reflected light on a linear focus. The focusing body is arranged between the reflector and the linear focus of the reflector, and the light reflected by the reflector can be transmitted to focus the light on the point focus. The number of the focusing bodies may be one or more. The light receiving unit is arranged on the downstream side in the traveling direction of the light passing through the focusing body, and can receive the light passing through the focusing body.

In one embodiment, the reflector has a concave reflecting surface that is curved in only one direction. The reflecting surface preferably has any shape selected from the group consisting of a parabolic cylinder surface, a dipole cylinder surface, an elliptic cylinder surface, and a cylinder surface.

In one embodiment, the one or more concentrators may include plano-convex columnar lenses or biconvex columnar lenses, or a combination thereof. In another embodiment, in the case where the focusing body is composed of a plurality of columnar lenses, the plurality of columnar lenses include a plano-convex columnar lens, a biconvex columnar lens, or a combination thereof. Thus, it may include a plano-concave columnar lens, a biconcave columnar lens, or a combination thereof.

In one embodiment, when there are a plurality of converging bodies, the plurality of converging bodies are for correcting the upstream side converging body arranged on the upstream side in the traveling direction of light and the distortion of the light transmitted through the upstream side converging body. And a downstream side focusing body of the above.

According to the present invention, the light reflected by the first reflecting mirror may be focused by using the columnar lens, complicated optical calculation for obtaining an image is not required, and the first reflecting mirror is highly polished. Since an expensive mortar-shaped parabolic mirror that requires technology is not used, it is possible to easily and inexpensively manufacture even a medium-sized or larger reflective telescope.

Further, according to the present invention, it is not necessary to use a complicated concave reflecting mirror having a curved surface shape as the second reflecting mirror, and a columnar lens having a stable optical shape that can be manufactured using glass or resin is provided. Since it can be used as a light collector, the light collector can be easily fixed in the hollow by a simple structure.

Furthermore, in the optical system of the present invention, the focal point can be easily arranged outside the optical system as in the conventional Newton type telescope, so that it is easy to add an optical device such as an eyepiece or a light receiving element.

Further, according to the present invention, since the first reflecting mirror can be manufactured to be lightweight, the mirror surface distortion due to gravity can be reduced, and the generated distortion can be easily corrected by using a columnar lens or the like. You can

It is a schematic diagram which shows the structure of the optical system by one Embodiment of this invention. FIG. 2 is a diagram of the optical system of FIG. 1 as viewed from the X-axis direction, showing the relationship between the positions of the columnar lens, the screen and the object, and the positions of the focal points of the primary mirror and the columnar lens, with the position of the primary mirror as the origin. .. 3 is a photograph showing an experiment when an object (character A) arranged at a distance is projected on a screen using the optical system according to the embodiment of the present invention, and is the character A used as an object. 3B is a photograph showing an experiment when an object (character A) arranged at a distance is projected on a screen using the optical system according to the embodiment of the present invention, and is a projected image of the character A in FIG. 3A. 4 is a photograph showing an experiment when an object (character A) arranged closer to the case of FIG. 3 is projected on the screen by using the optical system according to the embodiment of the present invention, and is the character A used as the object. .. 4A is a photograph showing an experiment when an object (letter A) arranged closer to the case of FIG. 3 is projected on a screen by using the optical system according to the embodiment of the present invention, and a projected image of the letter A in FIG. 4A. Is. 6 is a graph showing the relationship between the position of an object and the position of a screen in the optical system according to the embodiment of the present invention. 6 is a graph showing the relationship between the position of an object and the position of a columnar lens in the optical system according to the embodiment of the present invention. 6 is a graph showing the relationship between the position of an object and the difference between the position of the screen and the position of the cylindrical lens in the optical system according to the embodiment of the present invention. 6 is a photograph showing an experiment when an object is projected on a screen in an optical system according to an embodiment of the present invention, and is a projected image of a character A when a correcting columnar lens that corrects lateral distortion is used. FIG. 6 is a photograph showing an experiment when an object is projected on a screen in the optical system according to the embodiment of the present invention, and is a projected image when the correcting columnar lens is not used (reprinted in FIG. 3B).

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration of an optical system OS according to an embodiment of the present invention. In FIG. 1, as shown in the figure, the horizontal axis of the paper is the y-axis, the vertical axis of the paper perpendicular to the y-axis is the z-axis, and the axis perpendicular to the y-axis and the z-axis is the x-axis. The axis. The optical system OS is arranged on the optical axis of the main mirror M (reflector) that reflects the light from the object K and the light reflected from the main mirror M, and has a column shape that transmits the light reflected by the main mirror M. And a lens L (focusing body). The light from the object K may be light reflected by the object K or light emitted from the object K, and may be visible light or electromagnetic waves other than visible light. The optical system OS further includes a screen S (light receiving unit) that receives the light transmitted through the columnar lens L.

In the optical system OS of FIG. 1, the primary mirror M, the columnar lens L, and the screen S are arranged on a straight line on the y-axis, but the arrangement is not limited to this. M and the columnar lens L are arranged on the y-axis, and the light passing through the columnar lens L is extracted to the side by using the oblique mirror arranged on the y-axis, and is received by the screen S arranged on the side. You may do so.

[Configuration of Optical System According to the Present Invention]
(Primary mirror)
The primary mirror M has a concave reflecting surface 12 that is curved only in one direction (that is, only in the y-axis direction in FIG. 1 ), and this reflecting surface 12 reflects light from the object K. be able to. The concave shape of the reflecting surface 12 is not limited, but may be a parabolic cylinder surface, an elliptic cylinder surface, a cylinder surface, a dipole cylinder surface, or the like, and focuses on one point on the y-axis. In addition to being able to do so, there is no aberration, so it is more preferable to use a parabolic prism surface. However, in the present invention, even if aberration occurs due to the primary mirror, it is possible to absorb the aberration by disposing a plurality of appropriately selected correction columnar lenses, so that the reflecting surface 12 has a parabolic shape as a concave shape. It is relatively easy to adopt a shape other than the pillar surface. When the shape of the reflecting surface 12 is the main mirror M having a parabolic cylindrical surface, for example, a single mirror surface plate with the mirror surface serving as the reflecting surface 12 inside is parabolic y=ax ² (a is a constant). It can be manufactured by bending only along the y-axis direction. For example, in the case of the primary mirror M curved along the parabola y=ax ² , the focus of the parabola is y=1/(4a), so that the screen S of FIG. If it is arranged at a position, a can be determined from that position and the shape of the reflecting surface 12 of the primary mirror M can be designed.

The primary mirror M can focus the light reflected by the concave reflecting surface 12 on a linear focus at any position in the y-axis direction. The shape of the portion of the main mirror M on the side opposite to the reflecting surface is not particularly limited. When realizing the telescope using this optical system, for example, the main mirror M may be fixed to the inside of the lens barrel forming the telescope by using an appropriate support or the like.

The size of the primary mirror M is not limited, and can be appropriately determined according to conditions such as the distance to the observed object and the required focusing power. The material that can be used as the reflecting surface 12 of the primary mirror M is not limited, but it is preferable that the material has little deformation due to thermal expansion and can be easily processed, and it can be processed according to conditions such as application and allowable weight. Therefore, aluminum, stainless steel, glass, resin, or the like can be used as appropriate. When glass or resin is used, the reflecting surface 12 can be formed by using these materials as a base material and depositing a metal or attaching a mirror surface plate on the surface thereof. The reflecting surface 12 can be manufactured based on a mold formed by using a general-purpose numerical control machine tool or the like. If the primary mirror M is made of a shape memory alloy, for example, the primary mirror M wound in a roll shape is mounted on a rocket, transported to a satellite orbit, and deployed in orbit to construct a huge space telescope. You can also

(Columnar lens)
The columnar lens L has a column axis 22 extending in the x-axis direction and can be a columnar lens having a convex shape in the bending direction of the primary mirror M (y-axis direction). It is arranged between the linear focal point of the mirror M. The columnar lens L is arranged such that the direction of the column axis 22 (x-axis direction) is orthogonal to the bending direction of the primary mirror M (y-axis direction), and therefore the light reflected by the primary mirror M is transmitted through the column axis 22. It is possible to focus on a point focus by transmitting light from a direction perpendicular to.

The shape of the columnar lens L is not limited, but a side surface of the primary mirror M facing the reflecting surface 12 is a flat surface, and the opposite side surface is a convex surface. A biconvex columnar lens having a convex surface on both the side surface facing the reflecting surface 12 of M and the side surface on the opposite side can be appropriately selected and used according to the required focal length. A plano-convex columnar lens is preferably used for increasing the focal length, and a biconvex columnar lens is preferably used for shortening the focal length. Further, by using a lens having a cylindrical Fresnel surface as the columnar lens L, it is possible to manufacture a large telescope at a lighter weight and at a lower cost. When a telescope is realized by using this optical system, the columnar lens L is preferably movably supported on a rail installed inside the lens barrel so as to extend in the optical axis direction.

The number of columnar lenses L is not limited to one and may be plural. For example, a plurality of columnar lens groups L ₁ to L _n are arranged on the y-axis depending on the shape of the reflecting surface 12 of the primary mirror M, the final use of the image, and the like, and It may be configured such that the light transmitted through the lens L _n of the position is focused on the point focus.

Further, for example, when distortion occurs between an image generated by the primary mirror M and an image generated by one columnar lens L due to different magnifications in the horizontal direction and the vertical direction, the columnar lens L (that is, By disposing another columnar lens L′ behind (ie, on the upstream side in the traveling direction of the reflected light of the primary mirror M) (that is, on the downstream side in the traveling direction of the reflected light of the primary mirror M), the distortion can be corrected. .. As the columnar lens L′ used in this application, for example, when it is desired to correct the distortion in the x-axis direction, a column axis in a direction orthogonal to the column axis 22 in the x-axis direction of the columnar lens L, that is, a column axis in the z-axis direction. A columnar lens having a can be used. Further, as another columnar lens L′, for example, when it is desired to correct the distortion in the z-axis direction, the columnar axis in the direction parallel to the columnar axis 22 of the columnar lens L in the x-axis direction, that is, the columnar axis in the x-axis direction is set. A columnar lens having the same can be used.

When used as the columnar lens groups L ₁ to L _n , all of the lens groups L ₁ to L _n may be plano-convex columnar lenses or may be biconvex columnar lenses. Alternatively, one or a plurality of plano-convex columnar lenses and one or a plurality of biconvex columnar lenses may be appropriately combined. The columnar lens groups L ₁ to L _n include one or more plano-concave columnar lenses in addition to a plurality of plano-convex columnar lenses, a plurality of biconvex columnar lenses, or a combination thereof. It may include one or a plurality of biconcave columnar lenses, or a lens group combining these. The plano-concave columnar lens and/or the biconcave columnar lens is arranged so that the direction of the column axis (that is, the x-axis direction) is parallel to the plano-convex columnar lens and/or the biconvex columnar lens. Is located in.

The size of the columnar lens L is not limited, but it is preferable to make it as small as possible from the viewpoint of weight reduction. The height of the columnar lens L (that is, the length in the Z-axis direction) can be determined according to the height of the primary mirror M (the length in the Z direction). The material of the columnar lens L is not particularly limited, and glass or resin can be appropriately used according to conditions such as application and allowable weight.

(screen)
Screen S is arranged in the traveling direction downstream side of the light transmitted through the columnar lens L or columnar lens group L _{1 ~} L _n, can receive light transmitted through the columnar lens L or columnar lens group L _{1 ~} L _n .. In FIG. 1, the screen S is used as an example of the light receiving unit, but the present invention is not limited to this, and it may be an image pickup device such as a CCD or CMOS arranged at the position of the screen S, or an eyepiece. You can When a telescope is realized by using this optical system, the screen S is preferably movably supported on a rail installed in the lens barrel so as to extend in the optical axis direction.

[Design of Optical System According to the Present Invention]
Next, a method of designing the optical system according to the present invention will be described. 2 is a view of the optical system of FIG. 1 viewed from the x-axis direction. The axis extending in the left-right direction in the figure is the y-axis, and the axis extending in the up-down direction in the figure is the z-axis. In FIG. 2, with the position of the primary mirror M as the origin O, the positions of the columnar lens L, the screen S and the object K on the y-axis, and the position of the focus of the primary mirror M on the y-axis y _FM and the columnar lens L. The relationship with the position y _FL of the focal point on the y-axis is shown. Here, in order to design the optical system according to the present invention, when the main mirror M and the columnar lens L having a certain focal length are used, the position y of the columnar lens L with respect to the position y _{K of the} object K is used. _It is necessary to determine _L and the position y _S of the screen.

Light emitted from the object K and incident on the primary mirror M from the right direction in FIG. 2 is a concave reflecting surface 12 of the primary mirror M (in the example of FIG. 2, a curved surface along a parabola of y=ax ² ). Is reflected by. The reflected light forms a linear focus extending in the z-axis direction at the position of the focal point y=1/(4a)=y _FM of the parabola y=ax ² . When the columnar lens L is arranged at the position of y=y _L between the linear focus and the reflecting surface 12, the light from the reflecting surface 12 is contracted in the z-axis direction by the columnar lens L, and y=y _FL Focus on a point in a dot pattern.

Here, the position on the x-axis at the point where the optical path connecting the focal point 1/(4a) of the primary mirror M on the y-axis and the end of the columnar lens L intersects with the primary mirror M is x′, and the columnar lens L The distance from the focal point of the primary mirror M is f (=focal length of the columnar lens L), and the distance between the y-axis and the end of the columnar lens L (=1/the length parallel to the column axis of the columnar lens L). If 2) is α,
α/f=x'/(1/4a)
Therefore, x'is
x'=α/4af
Becomes Therefore, the primary mirror M and the columnar lens L are designed so that x′ is increased in order to increase the condensing power, and a and f are decreased and α is increased in order to increase x′. Will be done.

Generally, when a convex lens having a focal length f is used and an object is placed farther than the focal length f of the convex lens, the magnification m of the convex lens having the focal length f is the distance from the object to the convex lens is a, and the distance from the convex lens to the image is Let be b

It is represented by. According to the calculation of the magnification, in the case of the arrangement of the primary mirror M and the columnar lens L shown in FIG. 2, the magnification m _{x in the} x direction is the position y _M =O of the primary mirror M, the position y of the screen S. _{Using S 1} , the position y _{K of the} object K, and the focus position y _FM of the primary mirror M,

It can be expressed as. Further, the magnification _{m z} in the z-direction, using the position _{y L} of the columnar lens L, the position _{y S} of the screen, the position _{y K} of the object K, the focal position _{y FL} columnar lens L,

It can be expressed as.

From equations (2) and (3),

Here, assuming that the focal length of the columnar lens L is f, the focal position of the columnar lens L is y _FL =y _L +f, so the left side of (4) is

Becomes Summarizing equation (5) for y _L ,

Therefore, when y _L is calculated from the equation (6),

Becomes By returning A of the expression (7) using the expression (4), the following expression is obtained.

Here, when x is sufficiently larger than 1, the following approximate expression,

If the object K is sufficiently far away (y _K >>y _FM ) by using the fact that

Therefore, the position of the columnar lens L does not depend on the position of the object K, and is determined only by the focal position y _FM of the primary mirror M and the focal length f of the columnar lens L. Further, when the object K is sufficiently distant, the incident light is parallel light, and therefore, in order to display an image on the screen S,

Becomes

Here, as the main mirror M, a stainless mirror plate (100 mm×300 mm) curved along a parabola of y=ax ² is used, and as the columnar lens L, a column axis length 14 mm×thickness 14 mm×height 58 mm, The experiment was conducted using a transparent resin biconvex lens having a focal length f=65 mm. When the parabolic shape of the focal position y _FM =1/(4a)=165 mm of the primary mirror M is used, the position y _{S of the} screen _S is 165 mm from the formula (10). Further, from the expression (9), the position y _L of the columnar lens _L is 100 mm. When the position of the primary mirror M is set to y _M =0 mm, the columnar lens L is placed at the position of y _L =100 mm, and the screen S is placed at the position of y _S =165 mm, the inverted image of the outdoor scenery 100 m ahead is obtained. It was possible to project on the screen S.

Next, the letter A was prepared as the object K and arranged at the position of the distance y _K =2000 mm. The conditions for the primary mirror M and the columnar lens L are the same as above. From the formula (4), the position of the screen S is y _S =180 mm. Further, the position of the columnar lens L is y _L =113 mm from the formula (8).
Becomes FIG. 3 is a photograph showing an experiment when the character A is projected on the screen. FIG. 3A is the character A used as an object, and FIG. 3B is a projected image of the character A on the screen S. The size of the letter A was 280 mm in width and 210 mm in length. The image on the screen S was projected upside down, and the measured size of the character A on the screen was 22 mm in the horizontal direction and 6 mm in the vertical direction. On the screen S, it can be seen that the character A has been deformed (spread in the horizontal direction) and projected.

Further, the letter A was prepared as the object K and arranged at the position of the distance y _K =730 mm. The conditions for the primary mirror M and the columnar lens L are the same as above. The position of the screen S is y _S =213 mm from the formula (4), and the position of the columnar lens L is y _L =143 mm from the formula (8). FIG. 4 is a photograph showing an experiment when the character A is projected on the screen. FIG. 4A is a character A used as an object, and FIG. 4B is a projected image of the character A on the screen S. Also in this case, as in the case of FIG. 3, the character A is deformed and projected on the screen S.

FIG. 5 is a diagram showing the equations (4) and (8) as a graph. 5A is a graph showing the relationship between the position _{y S} position _{y K} and the screen S of the object K when defining the focal position _{y FM} of the main mirror M in equation (4), and the vertical axis _y S ( The range of the scale is 100 mm to 300 mm, and the horizontal axis represents y _K (the range of the scale is 0 mm to 30000 mm). Further, FIG. 5B, the relationship between the position y _L position y _K and the columnar lens L on the object K when defining the focal length f of the focal position y _FM and the columnar lens L of the primary mirror M in (8) In the graph shown, the vertical axis represents y _L (scale range is 100 mm to 150 mm), and the horizontal axis represents y _K (scale range is 0 mm to 30000 mm). Both the screen S and the columnar lens L may be arranged at a fixed position when the object K is at a distance. Further, in FIG. 6, the position _{y K} of the object K on the horizontal axis, there graphically the difference a _(y S -y _L) was the vertical axis between the position _{y L} position _{y S} and the columnar lens L of the screen S The vertical axis represents y _S -y _L (scale range is 60 mm to 75 mm), and the horizontal axis represents y _K (scale range is 0 mm to 30000 mm). From FIG. 6, it can be seen that the difference asymptotically approaches 65 mm when the object K is at a distance, and this value is equal to the focal length of the columnar lens L. The positional relationship between the columnar lens L and the screen S shown in FIGS. 5 and 6 can be realized by, for example, using motors that move the columnar lens L and the screen S separately and electronically controlling these motors. it can.

As described above, in the example shown in FIG. 3, that is, the example in which the character A is arranged at the position of the distance y _K =2000 mm, the character A is deformed and projected on the screen S. The values of the magnifications m _x and m _z of the deformed projection image A with respect to the character A are calculated by using the equations (2) and (3).
m _x =180/2000=0.09 times m _z =(180-113)/(2000+113)=0.0317 times. Therefore, the calculated image size is
Width 280 mm x 0.09 = 25.2 mm
Vertical 210 mm x 0.0317=6.66 mm
And almost agrees with the measured value. When the object K is sufficiently far away (y _K =∞), the ratio between the x-direction magnification m _x and the y-direction magnification m _y of the object K is

Therefore, the distortion of the projected image on the screen S is determined by the positions of the screen S and the columnar lens L.

Distortion of the projected image on the screen S is obtained by disposing another convex columnar lens L′ in the subsequent stage of the columnar lens L (that is, on the downstream side in the light traveling direction) so that the aspect ratio of the projected image becomes an object. It can be easily corrected to have the same aspect ratio as K. The columnar lens L′ is a columnar lens having a column axis in a direction orthogonal to the column axis 22 of the columnar lens L, and may be installed under the condition that m<1 in the expression (1). FIG. 7A is a projected image on the screen S when the columnar lens L′ is arranged on the screen S side of the columnar lens L such that the column axis of the columnar lens L is orthogonal to the column axis 22 of the columnar lens L. .. As the columnar lens L′ at this time, a biconvex lens having a central axis length of 25 mm×thickness of 9 mm×height of 40 mm and a focal length of 50 mm was used, and this lens was arranged at a position 120 mm from the main mirror M. It can be seen that the projected image of FIG. 7A is laterally compressed with respect to the projected image shown in FIG. 7B (reprinted in FIG. 3B).

M primary mirror L, L ', L "shaped lenses _L 1 ~ _{L n} columnar lens group S screen K object 12 primary mirror M position y on the y-axis of the cylindrical axis _{y M} primary mirror M of the reflecting surface 22 shaped lenses L of Position of the _L columnar lens L on the y-axis y _FM Position of the focus of the primary mirror M on the y-axis y Position of the focus of the _FL columnar lens on the y-axis y _S Position of the screen S on the y-axis y _K Object K Position on y-axis

Claims

A reflector that allows light from an object to be reflected by a reflecting surface and also allows the reflected light to be focused on a linear focus,
One or a plurality of focusing bodies that are arranged between the reflector and the linear focus of the reflector and focus the light to a point focus by transmitting the light reflected by the reflector.
An optical system comprising: a light receiving unit, which is arranged on a downstream side in a traveling direction of light passing through the one or more focusing bodies and receives light transmitted through the one or more focusing bodies.
The optical system according to claim 1, wherein the reflector has a concave reflecting surface that is curved only in one direction.
The optical system according to claim 2, wherein the reflecting surface has any shape selected from the group consisting of a parabolic cylinder surface, a dipole cylinder surface, an elliptic cylinder surface, and a cylinder surface.
The optical system according to any one of claims 1 to 3, wherein the one or more converging bodies include a plano-convex columnar lens, a biconvex columnar lens, or a combination thereof.
The optical system according to claim 4, wherein the focusing body is composed of a plurality of columnar lenses, and the plurality of columnar lenses further include a plano-concave columnar lens, a biconcave columnar lens, or a combination thereof. ..
A plurality of the converging bodies are provided, and the plurality of converging bodies include an upstream converging body arranged on the upstream side in the traveling direction of light and a downstream converging body for correcting distortion of light transmitted through the upstream converging body. An optical system according to any one of claims 1 to 5, including a body.