JPH08292372A - Reflection type zoom optical system and image pickup device using the system - Google Patents

Abstract

PURPOSE: To provide a reflection type zoom optical system and image pickup device using the system for which the arrangement accuracy of a reflection mirror frequently required for a mirror optical system is relaxed while miniaturizing the entire mirror optical system. CONSTITUTION: Plural reflecting planes composed of optical elements or/and surface reflection mirrors, which are constituted so that light flux can be made incident from one refracting plane into the inside of a transparent body and can be emitted from the other refracting plane after being repeatedly reflected on plural reflecting planes by forming two refracting planes and plural reflecting planes on the surface of the transparent object, are integrally formed and plural optical elements, which are constituted so that the incident light flux can be emitted after being repeatedly reflected on plural reflecting planes, are provided. Then, the image of an object is formed through plural optical elements B1-B3 and the relative positions of two optical elements B2 and B3 among the plural optical elements B1-B3 are changed at least so that zooming can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type zoom optical system and an image pickup apparatus using the same, and in particular, a plurality of optical elements having a plurality of reflecting surfaces are used, of which the relative position of at least two optical elements. Is suitable for a video camera, a still video camera, a copying machine, etc., which is zoomed (variable magnification) by displacing.

[0002]

2. Description of the Related Art Conventionally, various photographing optical systems using a reflecting surface such as a concave mirror or a convex mirror have been proposed. FIG. 59 shows 1
FIG. 3 is a schematic view of a so-called mirror optical system including one concave mirror and one convex mirror.

In the mirror optical system shown in FIG. 1, an object light beam 104 from an object is reflected by a concave mirror 101, converges toward the object side, is reflected by a convex mirror 102, and then is reflected on an image plane.
The image is formed on 103.

This mirror optical system is basically based on the structure of a so-called Cassegrain type reflecting telescope, and by folding the optical path of a telescopic lens system having a long lens length, which is composed of a refracting lens, by using two opposing reflecting mirrors, The purpose is to reduce the overall length of the optical system.

Also in the objective lens system constituting the telescope, for the same reason, there are known many types in which the total length of the optical system is shortened by using a plurality of reflecting mirrors in addition to the Cassegrain type.

As described above, a compact mirror optical system is obtained by efficiently folding the optical path by using a reflecting mirror instead of a lens of a taking lens having a long overall lens length.

However, in general, in a mirror optical system such as a Cassegrain type reflecting telescope, there is a problem that a part of the object beam is vignetted by the convex mirror 102. This problem is caused by the presence of the convex mirror 102 in the passage area of the object light beam 104.

In order to solve this problem, a reflecting mirror is decentered and used to prevent the passing area of the object light beam 104 from being blocked by other parts of the optical system, that is, the chief ray of the light beam.
Mirror optics have also been proposed which separates 106 from the optical axis 105.

FIG. 60 is a schematic view of a mirror optical system disclosed in US Pat. No. 3,674,334, in which a part of a reflecting mirror rotationally symmetric with respect to the optical axis is used to mainly reflect an object light beam. The ray is separated from the optical axis to solve the above-mentioned vignetting problem.

The mirror optical system shown in FIG. 1 has a concave mirror 111, a convex mirror 113 and a concave mirror 112 in the order of passage of a light beam.
It is a reflection mirror that is rotationally symmetric with respect to. Among them, concave mirror
By using the reference numeral 111 only on the upper side of the paper with respect to the optical axis 114, the convex mirror 113 only on the lower side of the paper with respect to the optical axis 114, and the concave mirror 112 only on the lower side of the paper with respect to the optical axis 114, the object light flux 115
The principal ray 116 of is separated from the optical axis 114 to constitute an optical system in which the vignetting of the object light beam 115 is eliminated.

FIG. 61 is a schematic view of a mirror optical system disclosed in US Pat. No. 5,063,586. The mirror optical system in the figure solves the above problem by decentering the central axis of the reflecting mirror with respect to the optical axis and separating the principal ray of the object light beam from the optical axis.

In the figure, when the vertical axis of the object surface 121 is defined as the optical axis 127, the central coordinates and central axes of the respective reflecting surfaces of the convex mirror 122, the concave mirror 123, the convex mirror 124 and the concave mirror 125 The axes 122a, 123a, 124a, 125a connecting the center of the reflecting surface and the center of curvature of the surface are decentered with respect to the optical axis 127. In the figure, by appropriately setting the eccentricity amount and the radius of curvature of each surface at this time, it is possible to prevent vignetting of the object light beam 128 by each reflection mirror and to efficiently form the object image on the image forming surface 126. There is.

In addition, in US Pat. No. 4,737,021 and US Pat. No. 4,265,510, a part of a reflecting mirror rotationally symmetric with respect to the optical axis is used to avoid vignetting, or the central axis of the reflecting mirror is used as an optical axis. A configuration is disclosed in which the shaft is eccentric to avoid vignetting.

By the way, there is also known a zooming technique for changing the image forming magnification (focal length) of the photographing optical system by relatively moving a plurality of reflecting surfaces constituting the mirror optical system.

For example, in US Pat. No. 4,812,030, in the configuration of the Cassegrain reflection telescope shown in FIG. 59, the distance from the concave mirror 101 to the convex mirror 102 and the convex mirror 10
A technique for varying the magnification of a photographic optical system by relatively changing the distance from 2 to the image plane 103 is disclosed.

FIG. 62 shows another embodiment disclosed in the publication. In the figure, the object light beam 138 from the object is incident on the first concave mirror 131, reflected on this surface, becomes a convergent light beam, is directed toward the object side, is incident on the first convex mirror 132, and is reflected on the image formation surface side here. It becomes a substantially parallel light flux and the second convex mirror 134
Is incident on the second concave mirror 135 and is reflected there to form a convergent beam, which is imaged on the image plane 137.

In this structure, the distance between the first concave mirror 131 and the first convex mirror 132 is changed and the second convex mirror 13 is changed.
Zooming is performed by changing the distance between the fourth concave mirror 135 and the second concave mirror 135 to change the focal length of the entire mirror optical system.

Further, in US Pat. No. 4,993,818, the image formed by the Cassegrain type reflecting telescope shown in FIG. 59 is secondarily formed by another mirror optical system provided in the subsequent stage, and this secondary combination is carried out. The magnification of the entire imaging system is changed by changing the image forming magnification of the mirror optical system for images.

These reflection type photographing optical systems have a large number of constituent parts, and it is necessary to assemble the respective optical parts with high precision in order to obtain necessary optical performance. Particularly, since the relative positional accuracy of the reflecting mirrors is strict, it is necessary to adjust the position and angle of each reflecting mirror.

As one method for solving this problem, a method has been proposed in which, for example, a mirror system is formed into one block so as to avoid an error in assembling an optical component that occurs during assembly.

Conventionally, there are optical prisms such as a pentagonal roof prism and a Porro prism used in a finder system as an example in which a large number of reflecting surfaces form one block.

Since a plurality of reflecting surfaces are integrally formed in these prisms, the relative positional relationship between the reflecting surfaces is accurately formed, and the positional adjustment between the reflecting surfaces is not necessary. However, the main function of these prisms is to invert the image by changing the traveling direction of the light beam, and each reflecting surface is formed by a plane.

On the other hand, there is also known an optical system in which the reflecting surface of the prism has a curvature.

FIG. 63 is a schematic view of a main part of an observation optical system disclosed in US Pat. No. 4,775,217. This observation optical system is an optical system for observing the scenery of the outside world and for observing the display image displayed on the information display with the scenery overlapping.

In this observation optical system, the display light beam 145 emitted from the display image of the information display body 141 is reflected by the surface 142 toward the object side and is incident on the half mirror surface 143 composed of a concave surface. Then, after being reflected by the half mirror surface 143, the display light flux 145 becomes a substantially parallel light flux due to the refractive power of the concave surface 143, and after refracting and transmitting through the surface 142, a magnified virtual image of the display image is formed and the It is incident on the pupil 144 to let the observer recognize the display image.

On the other hand, the object light beam 146 from the object is reflected by the reflecting surface 14
The light enters the surface 147 substantially parallel to 2 and is refracted to reach the concave half mirror surface 143. A semi-transmissive film is vapor-deposited on the concave surface 143, and a part of the object light flux 146 is transmitted through the concave surface 143,
2 is refracted and transmitted, and then enters the observer's pupil 144. As a result, the observer visually recognizes the display image in the external landscape in an overlapping manner.

FIG. 64 is a schematic view of a main part of an observation optical system disclosed in Japanese Patent Laid-Open No. 2-297516. This observation optical system is also an optical system for observing the scenery of the outside world and observing the display images displayed on the information display body while overlapping them.

In this observation optical system, the display light flux 154 emitted from the information display body 150 is the plane 15 that constitutes the prism Pa.
After passing through 7, the light enters the prism Pa and enters the parabolic reflection surface 151. The display light flux 154 is reflected by the reflecting surface 151 to become a convergent light flux and forms an image on the focal plane 156. At this time, the reflective surface 151
The display light flux 154 reflected by 2 constitutes the prism Pa.
The light reaches the focal plane 156 while totally reflecting between the two parallel planes 157 and 158, thereby achieving a reduction in the thickness of the entire optical system.

Next, the display light flux 154 emitted from the focal plane 156 as divergent light enters the half mirror 152 of a paraboloid while totally reflecting between the planes 157 and 158, and is reflected by the half mirror surface 152. At the same time, the refracting power forms a magnified virtual image of the display image and forms a substantially parallel light beam that passes through the surface 157 and enters the observer's pupil 153.
This allows the observer to recognize the display image.

On the other hand, the object light beam 155 from the outside world is a prism
The light passes through the surface 158b that constitutes Pb, the half mirror 152 that is a parabolic surface, the surface 157, and the pupil 153 of the observer. The observer visually recognizes the displayed image by overlapping it in the external landscape.

Further, as an example in which an optical element is used for the reflecting surface of the prism, for example, JP-A-5-12704 and JP-A-6-
There is an optical head for an optical pickup disclosed in Japanese Patent No. 139612. These reflect light from a semiconductor laser on a Fresnel surface or a hologram surface, then form an image on the disk surface, and guide the reflected light from the disk to a detector.

[0032]

The above-mentioned US Pat. No. 3,674,33
4, U.S. Pat.No. 5,063,586, U.S. Pat.
In the mirror optical system having the decentering mirror disclosed in the specification No. 265,510, each reflecting mirror is arranged with a different amount of decentering, which makes the mounting structure of each reflecting mirror very complicated, and the mounting accuracy is also high. It is very difficult to secure.

Further, the photographing optical system having the variable magnification function disclosed in US Pat. No. 4,812,030 and US Pat. No. 4,993,818 has many components such as a reflecting mirror and an imaging lens and is necessary. In order to obtain good optical performance,
It was necessary to assemble each optical component with high precision.

Further, since the relative positional accuracy of the reflecting mirrors becomes particularly severe, it is necessary to adjust the position and angle of each reflecting mirror.

The conventional reflection type photographing optical system is suitable for a so-called telephoto type lens system having a long optical system and a small angle of view. When obtaining a photographic optical system that requires the angle of view of a standard lens to the angle of view of a wide-angle lens, the number of reflecting surfaces required for aberration correction increases, so higher component accuracy and higher assembly accuracy are required. It was necessary, and the cost or the whole size tended to increase.

Further, the observation optical systems disclosed in the above-mentioned US Pat. No. 4,775,217 and Japanese Patent Laid-Open No. 2-297516 are all displayed on an information display unit arranged away from the observer's pupil. Focusing on changing the traveling direction of the light rays and the pupil image forming action to efficiently transmit the displayed image to the observer's pupil, and about the technology that positively corrects aberrations with a reflecting surface with a curvature. Is not directly disclosed.

In addition, JP-A-5-12704 and JP-A-6-1396
The optical systems for optical pickups disclosed in Japanese Patent No. 12 and the like are limited to the use of detection optical systems, and are related to imaging optical systems, particularly imaging devices using area-type imaging devices such as CCDs. The image performance was not satisfactory.

The present invention uses a plurality of optical elements integrally formed with a plurality of curved or flat reflecting surfaces, and appropriately changes the relative positions of at least two optical elements of the plurality of optical elements. By performing zooming, the overall size of the mirror optical system is reduced, and the reflective mirror optical system in which the arrangement accuracy (assembly accuracy) of the reflective mirror, which is often present in the mirror optical system, is moderated, and an image pickup apparatus using the same. For the purpose of providing.

In addition, the diaphragm is arranged on the most object side of the optical system, and the object image is formed at least once in the optical system, so that the reflective zoom optical system has a wide angle of view. However, by reducing the effective diameter of the optical system, and by providing an appropriate refracting power to a plurality of reflecting surfaces forming the optical element and arranging the reflecting surfaces forming each optical element eccentrically, An object of the present invention is to provide a reflective zoom optical system in which an optical path in the system is bent into a desired shape to shorten the total length of the optical system in a predetermined direction, and an image pickup apparatus using the same.

[0040]

The reflective zoom optical system according to the present invention comprises: (1-1) Two refracting surfaces and a plurality of reflecting surfaces are formed on the surface of a transparent body, and a light beam is formed from one refracting surface. A plurality of reflecting surfaces composed of an optical element or / and a surface reflecting mirror, which are configured to enter the inside of the transparent body, repeat reflection at the plurality of reflecting surfaces, and exit from another refracting surface, are integrally formed. A plurality of optical elements are configured so that the incident light beam is repeatedly reflected and emitted by the plurality of reflecting surfaces, and an image of an object is formed through the plurality of optical elements, and the plurality of optical elements are formed. Among the elements, it is characterized by performing zooming by changing the relative positions of at least two optical elements.

In particular, (1-1-1) the at least two optical elements that change the relative position have a reference axis for incidence and a reference axis for emission that are parallel to each other. (1-1-2) At least two optical elements that change the relative position move parallel to each other on one moving plane. (1-1-3) The at least two optical elements that change the relative position are such that the reference axis of incidence and the reference axis of emission are in the same direction. (1-1-4) One of the at least two optical elements for changing the relative position has a reference axis for incidence and a reference axis for emission that are directed in the same direction, and the other optical element is incident. The directions of the reference axis and the reference axis for injection are opposite to each other. (1-1-5) The at least two optical elements that change the relative position are such that the directions of the incident reference axis and the exit reference axis are opposite to each other. (1-1-6) One of at least two optical elements that change the relative position is moved to perform focusing. (1-1-7) Moving and focusing optical elements other than at least two optical elements that change the relative position. (1-1-8) The reflective zoom optical system forms an intermediate image of an object image at least once in its optical path. (1-1-9) Of the plurality of reflecting surfaces, each of the curved reflecting surfaces has a shape having only one symmetrical surface. (1-1-10) The reference axes of at least two optical elements that change the relative position are all on one plane. (1-1-11) At least a part of the reference axes of optical elements other than the at least two optical elements that change the relative position are on the plane. (1-1-12) At least one optical element of the plurality of optical elements is at least two optical elements whose normal to the reflecting surface at the intersection of the reference axis and the reflecting surface changes the relative position. Has a reflecting surface that is tilted with respect to the moving plane on which it moves. (1-1-13) At least two optical elements that change the relative position move on two moving planes that are inclined to each other. It is characterized by such things.

The image pickup apparatus of the present invention has (1-2) the reflective zoom optical system according to any one of (1-1) to (1-1-13), It is characterized in that an image of the object is formed on the image pickup surface of 1.

[0043]

[Embodiments] Before describing the embodiments, a description will be given of how to express the configuration data of the embodiments and common items of the entire embodiments.

FIG. 1 is an explanatory diagram of a coordinate system that defines the constituent data of the optical system of the present invention. In the embodiment of the present invention, the i-th surface is defined as the i-th surface along one light ray (shown by the one-dot chain line in FIG. 1 and referred to as a reference axis light ray) traveling from the object side to the image plane.

In FIG. 1, the first surface R1 is a diaphragm, the second surface R2 is a refracting surface coaxial with the first surface, the third surface R3 is a reflecting surface tilted with respect to the second surface R2, and the fourth surface R4. , The fifth surface R5 is a reflecting surface that is shifted and tilted with respect to each front surface, and the sixth surface R6 is the fifth surface
It is a refractive surface that is shifted and tilted with respect to R5. Second side
Each surface from R2 to the sixth surface R6 is formed on one optical element made of a medium such as glass or plastic, and is shown as the first optical element B1 in FIG.

Therefore, in the configuration of FIG. 1, the medium from the object surface (not shown) to the second surface R2 is air, the medium from the second surface R2 to the sixth surface R6 is a common medium, and the medium from the sixth surface R6 (not shown). The medium up to the seventh surface R7 is composed of air.

Since the optical system of the present invention is a decentered optical system, the surfaces constituting the optical system do not have a common optical axis. Therefore, in the embodiment of the present invention, first, an absolute coordinate system is set with the origin being the center of the effective ray diameter of the first surface.

In the embodiment of the present invention, the first
The center point of the effective ray diameter of the surface is defined as the origin, and the path of the ray (reference axis ray) passing through the origin and the center of the final image plane is defined as the reference axis of the optical system. Further, the reference axis in this embodiment has a direction. That direction is the direction in which the reference axis ray travels during imaging.

In the embodiments of the present invention, the reference axis that serves as the reference of the optical system is set as described above. However, the method of determining the axis that serves as the reference of the optical system is based on the optical design, the collection of aberrations, or the optical system. It is only necessary to adopt an axis convenient for expressing each surface shape that constitutes However, in general, a path of a ray passing through the center of the image plane, the stop, the entrance pupil, the exit pupil, the center of the first surface of the optical system, or the center of the final surface of the optical system is used as a reference axis that serves as a reference of the optical system. Set to.

That is, in the embodiment of the present invention, the reference axis passes through the first surface, that is, the center point of the effective ray diameter of the diaphragm surface,
The path along which the ray reaching the center of the final image plane (reference axis ray) is refracted / reflected by each refracting surface and reflecting surface is set as the reference axis. The order of each surface is set in the order in which the reference axis ray is refracted and reflected.

Therefore, the reference axis finally reaches the center of the image plane while changing its direction according to the law of refraction or reflection along the set order of each surface.

Basically, all of the tilt surfaces constituting the optical system of each embodiment of the present invention are tilted in the same plane. Therefore, each axis of the absolute coordinate system is defined as follows.

Z axis: Reference axis passing through the origin and toward the second surface R2 Y axis: Straight axis passing through the origin and forming 90 ° counterclockwise with respect to the Z axis in the tilt plane (in the plane of the paper of FIG. 1) : A straight line passing through the origin and perpendicular to the Z and Y axes (a straight line perpendicular to the paper surface of Fig. 1) Also, to express the surface shape of the i-th surface that constitutes the optical system, the shape of that surface in the absolute coordinate system Than the notation, the reference axis and the i-th
Since it is easier to understand the shape by recognizing the shape by setting the local coordinate system with the point where the surfaces intersect as the origin and expressing the surface shape of the surface in the local coordinate system, the configuration data of the present invention is displayed. In the embodiment, the surface shape of the i-th surface is represented by the local coordinate system.

The tilt angle in the YZ plane of the i-th surface is an angle θ with the counterclockwise direction being positive with respect to the Z axis of the absolute coordinate system.
Expressed in i (unit: °). Therefore, in the embodiment of the present invention, the origin of the local coordinates of each surface is on the YZ plane in FIG. Also
There is no surface eccentricity in the XZ and XY planes. Furthermore, the y and z axes of the local coordinate (x, y, z) of the i-th surface are inclined by an angle θi in the YZ plane with respect to the absolute coordinate system (X, Y, Z). To set.

Z-axis: Passes the origin of the local coordinates and forms an angle θ counterclockwise in the YZ plane with respect to the Z direction of the absolute coordinate system.
Straight line forming i y axis: A straight line passing through the origin of the local coordinates and 90 ° counterclockwise in the YZ plane with respect to the z direction x axis: A straight line passing through the origin of the local coordinates and perpendicular to the YZ plane Di is a scalar quantity representing the distance between the origins of the local coordinates of the i-th surface and the (i + 1) -th surface, and Ndi and νdi are the i-th surface and the (i
It is the refractive index and Abbe number of the medium between the (+1) planes.

In the optical system of the embodiment of the present invention, the entire focal length is changed (varies the magnification) by the movement of a plurality of optical elements. In the examples enumerating the numerical data of the present invention, the wide angle end
The optical system cross-sections and numerical data at three positions, (W), the telephoto end (T) and their intermediate position (M) are shown.

Here, in the optical element of FIG. 1, when the optical element moves in the YZ plane, it is the origin (Yi, Zi) of the local coordinates representing the position of each surface that changes the value at each zoom position.
In the examples including numerical data, the optical element that moves for zooming is represented only by the movement in the Z direction.Therefore, the coordinate value Zi is set to Zi in the order of the optical system at the wide-angle end, the middle, and the telephoto end.
(W), Zi (M), and Zi (T).

The coordinate value of each surface indicates the value at the wide-angle end, and is described as the difference from the wide-angle end at the middle and telephoto ends. Specifically, if the movement amount at the intermediate position (M) with respect to the wide-angle end (W) and the movement amount at the telephoto end (T) are a and b, respectively, it is expressed by the following formula: Zi (M) = Zi (W) + a Zi (T) = Zi (W) + b The signs of a and b are positive when each surface moves in the Z plus direction and negative when moving in the Z negative direction.
Also, the surface distance Di that changes with this movement is a variable,
The values at each variable power position are shown in a separate table.

Embodiments of the present invention have spherical and rotationally asymmetric aspherical surfaces. The radius of curvature R _i is shown for the spherical portion as a spherical shape. The sign of the radius of curvature R _i is the first
When the center of curvature is on the first surface side along the reference axis (one-dot chain line in FIG. 1) that advances from the surface to the image surface, it is minus, and when it is on the image forming surface side, it is plus.

Here, the spherical surface has a shape represented by the following equation:

[0061]

[Equation 1] Further, the optical system of the present invention has at least a rotationally asymmetric aspherical one side more, the shape is expressed by the following equation: A = (a + b) · (y 2 · cos 2 t + x 2) B = 2a ・ b ・ cos t [1 + {(ba) ・ y ・ sin t / (2a ・ b)} + [1 + {(ba)
・ Y ・ sin t / (a ・ b)}-{y ² / (a ・ b)}-{4a ・ b ・ cos ² t + (a + b) ² sin
² t} x ² / (4a ² b ² cos ² t)] ^1/2 ] as z = A / B + C ₀₂ y ² + C ₂₀ x ² + C ₀₃ y ³ + C ₂₁ x ² y + C ₀₄ y ⁴ + C ₂₂ x ² y ² + C ₄₀
x ^{4 Since the} above curved surface expression has only even-order terms with respect to x, the curved surface defined by the above curved surface expression has a plane symmetric shape with the yz plane as the symmetry plane. Furthermore, when the following conditions are satisfied, the shape is symmetrical with respect to the xz plane.

[0062] If the _{C 03 = C 21 = t =} 0 Furthermore _{C 02 = C 20 C 04 =} C 40 = C 22/2 is satisfied represents a rotation-symmetrical shape. If the above conditions are not satisfied, the shape is non-rotationally symmetric.

In each embodiment of the present invention, as shown in FIG. 1, the first surface (the entrance side of the optical system) is a diaphragm. The horizontal half angle of view u _Y is the aperture R1 in the YZ plane of FIG.
The maximum angle of view of the light beam incident on the vertical half field angle u _X is the maximum angle of view of the light beam incident on the stop R1 in the XZ plane. Also,
The diameter of the stop, which is the first surface, is shown as the stop diameter. This is related to the brightness of the optical system. Since the entrance pupil is located on the first surface, the diaphragm diameter is equal to the entrance pupil diameter.

Further, the effective image range on the image plane is shown as an image size. The image size is represented by a rectangular area in which the size in the y direction of local coordinates is horizontal and the size in the x direction is vertical.

Further, the size of the optical system is shown in the examples in which the constitutional data is given. The size is a size determined by the effective ray diameter at the wide-angle end.

Further, the lateral aberration charts of the examples in which the constituent data are given are shown. The lateral aberration diagram is the wide-angle end of each example.
(W), intermediate position (M), telephoto end (T)
The horizontal and vertical incident angles on R1 are (u _Y , u _X ), (0, u _X ),
_{(-u Y, u X),} (u Y, 0), (0,0), (- u Y, 0) and showing lateral aberration of the light flux incident angle made. In the lateral aberration diagram, the horizontal axis represents the entrance height to the pupil, and the vertical axis represents the aberration amount. Since each surface is basically plane-symmetrical with the yz plane as a plane of symmetry in each example, the plus and minus directions of the vertical angle of view are the same in the lateral aberration diagram, so the diagram is simplified. Therefore, the lateral aberration diagram in the minus direction is omitted.

The following Examples 1 to 4 are qualitative examples that do not list configuration data, and Examples 5 to 16 list configuration data.

It should be noted that, in Examples 1 to 4, surface symbols or the like are given to the respective optical elements constituting the optical elements, not according to the symbol nomenclature described above. That is, the diaphragm is B _L and the final image plane is P,
In the M-th optical element, from the first surface R _{m, 1} , R _{m, 2} , ... R
_The symbols _{m and n} are attached.

[Embodiment 1] FIG. 2 is a schematic view of the essential portions of Embodiment 1 of the present invention. This embodiment is an embodiment of an image pickup optical system of a so-called two-group type zoom lens. In the figure, B1 and B2 are the first and second optical elements having a plurality of curved reflecting surfaces. The first optical element B1 has concave concave surfaces R _{1,1 in} order from the object side.
And concave mirror R _1,2 / convex mirror R _1,3 / concave mirror R _1,4 / convex mirror R _1,5
Of the four reflecting surfaces and the convex refracting surface R _1,6 , and the direction of the reference axis incident on the first optical element B 1 and the direction of the reference axis _exiting from the first optical element B 1 are parallel and the same direction (direction).

The second optical element B2 has a convex refracting surface R from the object side.
_2,1 and convex mirror R _2,2・ Concave mirror R _2,3・ Convex mirror R _2,4・ Concave mirror R
_It is composed of four reflecting surfaces _{2 and 5} and a convex refracting surface R _2,6. Like the first optical element B1, the direction of the reference axis that enters the second optical element B2 and the direction of the reference axis that exits it. Are parallel and in the same direction.

B3 is an optical correction plate made of a parallel plate,
It is composed of a low-pass filter and infrared cut filter made of crystal.

P is an image pickup element surface which is a final image surface, and is an image pickup surface such as CCD (image pickup medium). B _L is a diaphragm arranged on the object side of the first optical element B1 (on the light beam incident side of the optical system), and A _i is the reference axis of the imaging optical system.

The first optical element B1 and the second optical element B2 constitute one element of the two-group zoom lens.

Next, the image forming action in this embodiment will be described. The light flux 8 from the object is incident on the concave refraction surface R _1,1 of the first optical element B 1 after the incident light amount is regulated by the diaphragm B _L.

Next, the light beam refracted and transmitted through the concave refracting surface R _1,1 is
The light is reflected by the concave mirror R _1,2 and is imaged on the primary imaging plane N1 by the power of the concave mirror.

As described above, once forming an object image in the first optical element B1 is effective in suppressing an increase in the effective ray diameter of the surface arranged on the image side of the stop _BL. .

The light flux which is primarily imaged on the primary image plane N1 is repeatedly reflected by the convex mirror R _1,3 , the concave mirror R _1,4 and the convex mirror R _1,5 ,
Each of the reflecting mirrors receives the power of converging or diverging to reach the convex refracting surface R _1,6 , and the light beam refracted there forms an object image on the secondary image forming surface N 2.

As described above, the first optical element B1 functions as a lens unit having desired optical performance as a whole having positive power by repeating refraction by the entrance / exit surface and reflection by a plurality of curved reflecting mirrors. ing.

The light flux from the object image on the secondary image plane N2 is
After passing through the convex refracting surface R _2,1 of the optical element B2 of
An image is formed on the tertiary image plane N3 through R _2,2 and the concave mirror R _2,3 .

This is because of the same reason that the object image is formed in the first optical element B1.
This is effective in suppressing an increase in the effective ray diameter of each surface in B2.

The light flux imaged on the tertiary image plane N3 is a convex mirror.
R _2,4 and the concave mirror R _2,5 repeat reflection, and are influenced by the power of the respective reflecting mirrors to reach the convex refracting surface R _2,6 , and the light beam refracted here passes through the optical correction plate B3. After passing, an image is formed on the image pickup element surface P.

As described above, the second optical element B2 forms the object image formed on the secondary image forming surface N2 by the first optical element B1 on the image pickup element surface.
The image is re-imaged on P, and like the first optical element B1, the refraction by the entrance / exit surface and the reflection by the plurality of curved reflecting mirrors are repeated to provide a desired optical performance, and an overall positive It functions as a lens unit that has power.

Further, in this embodiment, the first and second
By moving the optical elements B1 and B2 of relative to the image pickup element surface (imaging surface) P 1, the focal length (imaging magnification) of the photographing optical system is changed. (This is an operation called scaling or zooming.) The scaling operation will be described with reference to FIG. FIG. 3 is an optical layout diagram in which the first and second optical elements B1 and B2 of Example 1 are each a single thin lens and the photographing optical system is developed with respect to its reference axis. 3A is a layout drawing of the optical system in the wide-angle end state (W), and FIG. 3B is a layout drawing in the telephoto end state (T).

In the same figure, the focal length of the first optical element B1 is f ₁ , and the focal length of the second optical element B2 is f ₂ . When the optical system is at the wide-angle end, the distance from the front focal point F _{2 of} the second optical element B ₂ to the secondary image plane N 2 is x _W (-), the rear focal point is
The distance from F ₂ 'to the image plane P is x _W '. (The subscripts _W and _T mean the values when the optical system is at the wide-angle end and at the telephoto end, respectively.) According to Newton's imaging formula, x _W * x _W '= −f ₂ ² holds. Then, the imaging magnification β _2W of the second optical element B2 is β _2W = − (x _W ′ + f ₂ ) / (− x _W + f ₂ ) = f ₂ / x _W = −x _W ′ / f ₂ (1) and the focal length f _W at the wide-angle end are f _W = f ₁ * β _2W = f ₁ * f ₂ / x _W (2).

Here, the second optical element B2 moves while satisfying the Newton's imaging formula, and the second optical element B2 is corrected so as to correct the position change of the intermediate image forming surface N2 due to the movement of the second optical element B2. By moving the first optical element B1, the optical system changes the focal length without changing its final image forming position P 1.

It is assumed that the second optical element B2 is moved by a certain amount and zoomed from the wide-angle end (W) to the telephoto end (T). The distance from the front focal point F _{2 of} the second optical element B ₂ to the intermediate image plane N 2 is x
_{Assuming that T} (-) and the distance from the rear focal point F ₂ 'to the image plane P are x _T ', the imaging magnification β _2T of the second optical element B2 is β _2T = (x _T '+ f ₂ ). _{/ (-x T + f 2)} = f 2 / x T = -x T '/ f 2 (3), _: focal length f _T of the telephoto _{end, f T = f 1 * β} 2T = f 1 * f 2 / Since x _T (4), the zoom ratio Z of this optical system is Z = f _T / f _W = x _W / x _T (5).

In this way, by changing the relative positional relationship between the first optical element B1 and the second optical element B2 and between the second optical element B2 and the image pickup element surface P, the final image forming position P It is possible to change the focal length (imaging magnification) without changing. Next, focusing in Example 1
Can be achieved by moving any optical element that constitutes the optical system, but considering the load of the actuator for focusing, it is preferable to move the lightest optical element.

Further, when it is desired to make the moving amount of the optical element constant with respect to the distance to the object to be photographed regardless of the magnification change,
It is sufficient to move the first optical element B1 arranged closest to the object side.

The second optical element B2 that moves during zooming
By moving also during focusing, it is possible to make the variable-magnification actuator and the focusing actuator common.

The effect of this embodiment will be described.

In this embodiment, since the reflecting surfaces that move during zooming are unitized, the relative positional accuracy of each reflecting surface, which is most required in the conventional mirror optical system, is guaranteed. . Therefore, in this embodiment, the positional accuracy between the first optical element B1 and the second optical element B2 may be ensured, and the positional accuracy similar to that of the moving lens group in the conventional refracting lens system may be sufficient.

Since each optical element is configured as a lens unit integrally formed with a plurality of curved reflecting surfaces as compared with a refracting lens system, the number of parts of the entire optical system is reduced, and The cost can be reduced, and the cumulative error due to the mounting of parts is reduced.

By adopting a structure in which the object image is transmitted while performing image formation a plurality of times, the effective diameter of the light beam on each surface is suppressed to be small, and each optical element and the photographing optical system as a whole are made compact. There is.

Further, by setting the image formation size of the intermediate image formation to be relatively small with respect to the image pickup element surface size, the effective ray diameter of each surface is kept small when transmitting the object image.

In the case of the conventional photographing optical system, the diaphragm is often arranged inside the optical system. When the diaphragm is arranged inside the optical system, the effective beam diameter of the lens arranged on the object side of the diaphragm is large. Has a problem that the distance from the diaphragm increases as the angle of view increases.

In this embodiment, the diaphragm B _L is installed in the vicinity of the entrance surface of the first optical element B1 on the object side of the photographing optical system so that the photographing optical system produces a wide focal angle. The expansion of the effective beam diameter of the front group is suppressed.

By forming an object image in each optical element, it is possible to effectively suppress an increase in the effective ray diameter of the surface arranged on the image side of the diaphragm B _L.

The reference axes of the first optical element B1 and the second optical element B2 are all in the YZ plane. Therefore, by setting the movement of each optical element on a plane parallel to the YZ plane, even if the first optical element B1 and the second optical element B2 move during zooming, The parallelism with the plane on which each optical element moves is easily maintained, and it is easy to remove the parallel decentering of the optical elements B1 and B2 in the X-axis direction and the rotation around the Y-axis and Z-axis.

However, even if the YZ plane including the reference axis and the plane in which both optical elements move are inclined, if the direction vector in which the YZ plane including the reference axis moves during zooming is parallel to the moving plane, eccentricity No aberration will occur.

Since each optical element is arranged on one plane, it is possible to easily take a structure in which each optical element is incorporated from one direction, and the assembling becomes very easy.

In this embodiment, the secondary image plane N2 is the first
Although it is formed between the optical element B1 and the second optical element B2, the secondary image plane may be present inside the first optical element B1 or the second optical element B2.

Further, the moving direction of the optical element during zooming is to minimize the error that occurs during zooming unless the incident point position of the reference axis of each reflecting surface is changed when moving from the wide-angle end to the telephoto end. Incident on each optical element B1, B2,
The directions of the reference axes to be emitted are made parallel, and the movement of each optical element is also made to move in parallel along the reference axis line of incidence and emission to the optical elements.

In the present invention, when an optical element in which the reference axis directions of incidence and emission to each optical element are parallel, the emission direction is the same as or opposite to the incident direction. Different types of patterns are possible. When the exit direction is opposite to the entrance direction, the distance between the entrance side and the exit side changes by the same amount as the movement amount as the optical element moves, so the optical path length is doubled as a whole as a whole. Can be changed.

When the emission direction is the same as the incident direction, the positions of the incident reference axis and the emitting reference axis can be shifted to desired positions.

Since the embodiment of the present invention can be constructed by the above-mentioned two types of patterns, the present invention can increase the degree of freedom in optical arrangement.

However, the moving direction of the optical element does not need to be parallel to the reference axis direction of incidence and exit to the two optical elements. For example, the direction of the reference axis entering the optical system and the moving direction of the moving optical element are It may have an angle such as 30 °, 45 °, 60 °.

[Embodiment 2] FIG. 4 is a schematic view of the essential portions of Embodiment 2 of the present invention. This embodiment is an embodiment of an image pickup optical system of a so-called two-group type zoom lens. This embodiment is an embodiment in which the moving direction of the optical element that moves during zooming is not parallel to the direction of the incident reference axis of the optical element arranged closest to the object side.

In the figure, B1 and B2 are first and second optical elements having a plurality of curved reflecting surfaces. First optical element B1
Are, in order from the object side, a concave refracting surface R _1,1 and a concave mirror R _1,2 , a convex mirror R _1,3 , a concave mirror R _1,4 , a concave mirror R _1,5 , and four reflecting surfaces and a convex refracting surface R _1,6. And a lens unit having a positive refracting power as a whole. The direction of the reference axis that enters the first optical element B1 and the direction of the reference axis that exits from it are approximately 45
It has a slope of ゜.

The second optical element B2 has a concave refracting surface R from the object side.
_2,1 and concave mirror R _2,2・ Concave mirror R _2,3・ Convex mirror R _2,4・ Concave mirror R
_2,5-concave mirror R _{2, 6,} a concave mirror consists of six reflecting surfaces and the convex refracting surface R _{2, 8} of the R _{2, 7,} a lens unit having a positive refractive power as a whole. The direction of the reference axis incident on the second optical element B2 and the direction of the reference axis emitted from the second optical element B2 are parallel and opposite to each other.

B3 is an optical correction plate made of a parallel plate,
It is a crystal low-pass filter or infrared cut filter.

P is an image sensor surface, and is a CCD (imaging medium)
And the like. B _L is aperture disposed on the object side of the first optical element B1, A _i is a reference axis of the optical system.

The image forming operation of this embodiment will be described. The luminous flux from the object is regulated by the diaphragm B _{L in the} amount of incident light, and then the first
Refracting and transmitting through the concave refracting surface R _1,1 of the optical element B1 of
R _{1, 2,} convex mirror R _{1, 3,} plane mirror R _{l, 4,} repeatedly reflected by the concave mirror R _{1, 5,} receives the converging or diverging action by the power of each reflecting mirror, convex refractive surface R _{1 , 6} , where the light beam refracted here forms an object image on the intermediate image plane N1. In addition,
Even in the first optical element B1, the intermediate image of the object is once formed.

The light flux from the object image on the intermediate image plane N1 is
After passing through the concave refracting surface R _2,1 of the optical element B2 of
R _2,2 , concave mirror R _2,3 , convex mirror R _2,4 , concave mirror R _2,5 , concave mirror R
_The convex refracting surface R _2,8 is refracted through the concave mirror R _2,7 via the concave mirror R _2,7 and is emitted from the second optical element B 2. Incidentally, the intermediate image of the object is once formed also in the second optical element B2.

The light beam emitted from the second optical element B2 passes through the optical correction plate B3 and then forms an image on the image pickup element surface P.

In this embodiment, focusing for different object distances is performed by moving the second optical element B2. At this time, the movement of the second optical element B2 moves in parallel with the direction of the reference axis A _1,6 emitted from the first optical element B1, but the reference axis of incidence of the first optical element B1.
Since the direction of A _{0 and} the direction of the outgoing reference axis A _1,6 are inclined by about 45 °, the second optical axis is inclined with respect to the direction of the incoming reference axis A ₀ of the first optical element B 1. The direction in which the element B2 moves during focusing is inclined by about 45 °.

Therefore, although the second optical element B2 moves parallel to the directions of the reference axes A _1,6 and A _{2,8 which enter} and exit it during focusing, the second optical element B2 enters the first optical element B1. It moves with an inclination of 45 ° with respect to the direction of the reference axis A ₀ .

Also in this embodiment, as in the first embodiment, the first and second optical elements B1 and B2 move relative to the image forming plane P, so that the image forming magnification of the photographing optical system is increased. Change. However, Example 1 in which the direction of the reference axis that enters and exits each optical element and the moving direction of each optical element are all parallel
Unlike the above, since the direction of the reference axis that enters the first optical element B1 and the direction of the reference axis that exits the first optical element B1 are inclined by 45 °, the direction from the first optical element B1 Optical element
In order to maintain the direction of the reference axis incident on B2, the moving direction of the first optical element B1 is moved parallel to the direction of the incident reference axis of the second optical element B2.

[Embodiment 3] FIG. 5 is a schematic view of the essential portions of Embodiment 3 of the present invention. This embodiment is an embodiment of an image pickup optical system of a so-called two-group type zoom lens. In the figure, B1 and B2 are the first and second optical elements having a plurality of curved reflecting surfaces. The first optical element B1 has concave concave surfaces R _{1,1 in} order from the object side.
And concave mirror R _1,2 / convex mirror R _1,3 / concave mirror R _1,4 / convex mirror R _1,5
The lens unit has a negative refracting power as a whole and is composed of four reflecting surfaces and a concave refracting surface R _1,6 . As in the first embodiment, the direction of the reference axis A ₀ that enters the first optical element B1 and the direction of the reference axes A _{1,6 that exits} from the first optical element B1 are parallel and the same direction.

The second optical element B2 has a convex refracting surface R from the object side.
_2,1 and convex mirror R _2,2・ Concave mirror R _2,3・ Convex mirror R _2,4・ Concave mirror R
A lens unit having four positive refracting powers, which is composed of four reflecting surfaces _{2 and 5} and a convex refracting surface R _2,6 . Similarly to the first optical element B1, the direction of the reference axis A _1,6 which is incident on the second optical element B2 and the direction of the reference axis A _{2,6 which is} emitted from the second optical element B2 are parallel and the same direction.

B3 is an optical correction plate made of a parallel plate,
It is a crystal low-pass filter or infrared cut filter.

P is an image sensor surface, and is a CCD (imaging medium)
And the like. B _L is aperture disposed on the object side of the first optical element B1, A _i is a reference axis of the optical system.

The image forming operation of this embodiment will be described. The luminous flux from the object is regulated by the diaphragm B _{L in the} amount of incident light, and then the first
Refracting and transmitting through the concave refracting surface R _1,1 of the optical element B1 of
R _{1, 2,} convex mirror R _{1, 3,} the concave mirror R _{l, 4,} repeatedly reflected by the convex mirror R _{1, 5,} receives the converging or diverging action by the power of each reflecting mirror, concave refracting surface R _{1 , 6} , where the light is refracted and emitted from the first optical element B1. Incidentally, an intermediate image of the object is once formed in the first optical element B1.

Then, the light flux passes through the convex refracting surface R _2,1 of the second optical element B 2 and then is convex mirror R _2,2 , concave mirror R _2,3 and convex mirror R ₂ .
The reflection is repeated by R _2,4 and the concave mirror R _2,5 , and the convex refracting surface R _2,6 is refracted and emitted from the second optical element B 2. Incidentally, the intermediate image of the object is once formed also in the second optical element B2.

The light flux emitted from the second optical element B2 passes through the optical correction plate B3 and then forms an image on the image pickup element surface P.

In this embodiment, as in the first embodiment, the final optical image forming position P is set by moving the first optical element B1 and the second optical element B2 relative to the image forming plane P. The focal length (imaging magnification) of the optical system is changed without changing it.

The zooming effect of this embodiment will be described with reference to FIG. FIG. 6 is an optical layout diagram in which each optical element of Example 3 is a single thin lens and the optical system is developed with respect to its reference axis. In addition, FIG. 6A shows a state in which the optical system is at the wide-angle end.
FIG. 6B is a layout drawing of (W), and FIG. 6 (B) is a layout drawing of state (T) at the telephoto end.

In the figure, the focal length of the first optical element B1 is f ₁ (-), and the focal length of the second optical element B2 is f ₂ .
When the optical system is at the wide-angle end, the distance from the front focal point F _{2 of} the second optical element B2 to the image point of the first optical element B1 is x _W (-)
, If the distance from the rear focal point F ₂ 'to the image plane P is x _W ', and if the Newton's image formation formula x _W * x _W '= -f ₂ * f ₂ , then The imaging magnification β _2W of the second optical element B2 is β _2W =-(x _W '+ f ₂ ) / (-x _W + f ₂ ) = f ₂ / x _W = -x _W ' / f ₂ (6) The focal length f _W at the wide-angle end is f _W = f ₁ * β _2W = f ₁ * f ₂ / x _W (7).

Here, the second optical element B2 moves while satisfying the Newton's imaging formula, and the position change of the object point of the second optical element B2 due to the movement of the second optical element B2 is corrected. Thus, by moving the first optical element B1, the optical system can change the entire focal length without changing the final image forming position P 1.

It is assumed that the second optical element B2 is moved by a certain amount and the magnification is changed from the wide-angle end (W) to the telephoto end (T). In the telephoto end state, from the front focus F _{2 of} the second optical element B ₂ to the first
The distance to the image point of the optical element B1 of x _T (-), and the rear focal point F ₂ '
Assuming that the distance from the image plane to the image plane P is x _T ', the image forming magnification β _2T of the second optical element B2 is β _2T = (x _T ' + f ₂ ) / (− x _T + f ₂ ) = f ₂ / x _T = −x _T '/ f ₂ (8), and the focal length f _T at the telephoto end is f _T = f ₁ * β _2T = f ₁ * f ₂ / x _T (9), so the optical system zoom ratio Z of becomes _{Z = f T / f W =} x W / x T (10).

In the first embodiment, the secondary image plane N2 exists between the first optical element B1 and the second optical element B2, but in the present embodiment, the first optical element B1 as a whole is An object light flux having a negative refracting power from infinity is imaged as a virtual image on the object side, and the imaging relationship of the second optical element B2 is established with the virtual image position as an object point.

Contrary to the configuration of this embodiment, even if there is an optical element having a positive refractive power as a whole from the object side and an optical element having a negative refractive power behind it, each optical element By moving the elements relatively, the focal length (imaging magnification) of the photographing optical system can be changed.

[Embodiment 4] FIG. 7 is a schematic view of the essential portions of Embodiment 4 of the present invention. This embodiment is an embodiment of an image pickup optical system of a so-called three-group type zoom lens. In the figure, B1, B2,
B3 are first, second, and third optical elements each having a plurality of curved reflecting surfaces, and the first optical element B1 is, in order from the object side,
Concave refracting surface R _1,1 and concave mirror R _1,2・ Convex mirror R _1,3・ Concave mirror R _1,4
Consisting of the three reflecting surfaces and the convex refracting surface R _1,5 , having a positive refracting power as a whole, and entering the first optical element B 1
The direction of A _{0 and} the direction of the reference axis A _{1,5 to be} ejected are substantially right angles.

The second optical element B2 includes a plane R _2,1 and a concave mirror R _2,2 , a plane mirror R _2,3 , a convex mirror R _2,4 , a plane mirror R _2,5 from the object side.
_Consists of five reflecting surfaces of a concave mirror R _2,6 and a plane R _2,7 , having a positive refracting power as a whole, the direction of the reference axis A _1,5 entering the second optical element B2, and the reference emerging from this. The directions of the axes A ₂ , ₇ are parallel and opposite.

The third optical element B3 is, in order from the object side, four reflections of a convex refracting surface R3, ₁ , a convex mirror R3, ₂ , a concave mirror R3, ₃ , a concave mirror R3, ₄ and a convex mirror R3, _5. Surface and concave refracting surface R _3,6 , having a positive refracting power as a whole, the direction of the reference axis A _2,7 entering the third optical element B3 and the direction of the reference axis A _{3,6 exiting} from it. Are parallel and in the same direction.

B4 is a fourth optical element, which is a triangular prism composed of a convex refracting surface R _4,1 , a plane mirror R _4,2 and a plane R _{4,3 in} order from the object side, and a fourth optical element B4 Reference axis A incident on
The directions of ₃ , _{6 and} the direction of the reference axis A _{4,3 to be} ejected are substantially right angles.

B5 is an optical correction plate made of a parallel plate,
Examples are low-pass filters and infrared cut filters made of quartz.

P is an image pickup element surface, for example, an image pickup surface of a CCD (image pickup medium) or the like. B _L is a diaphragm arranged on the object side of the first optical element B 1, and A _i is a reference axis of the present optical system.

The image forming operation in this embodiment will be described. The light flux from the object is first incident on the first optical element B1 after the amount of incident light is regulated by the diaphragm B _L. The first optical element B1 forms a primary image plane N1 between its exit surface R _1,5 and the entrance surface R _{2,1 of} the second optical element B2.

The object image formed on the primary imaging plane N1 is
The optical element B2 and its exit surface R _{2, 7} the third optical element B3
It is reimaged on a two image forming plane N2 between the incident surface R _{3, 1} of.

The object image formed on the intermediate image forming surface N2 is between the exit surface R _3,6 of the third optical element B3 and the incident surface R _{4,1 of} the fourth optical element B4. The image is re-imaged on the tertiary image plane N3.

Then, the fourth optical element B4 converges the light beam from the object image formed on the tertiary image forming surface N3 and forms an image on the image pickup element surface P via the optical correction plate B5.

In this embodiment, in particular, in order to shorten the length in the Z direction in FIG. 7, the optical path is effectively folded by each optical element and the length in the Z direction is shortened remarkably. .

That is, the light beam incident on the first optical element B1 is incident on the concave refracting surface R _1,1 and is then arranged behind the concave mirror R 1.
It is reflected by ₁ , _{2 in the} direction perpendicular to the incident direction, that is, in the Y (-) direction.

Next, the object light beam is reflected in the Z (−) direction by the convex mirror R _1,3 to shorten the length of the optical system in the Z axis direction.

The object light beam reflected in the Z (-) direction is a concave mirror R
After being reflected again in the Y (-) direction by _1,4 , the convex refracting surface R _1,5
Of light and enters the second optical element B2.

In the second optical element B2, the object light is totally reflected on the plane R _2,3 and the plane R _2,5 ,
The ray effective area on the incident surface R _2,1 of the second optical element B _{2 and} the ray effective area on the plane R _2,3 overlap,
Further, the effective light area on the exit surface R _2,7 of the second optical element B2 and the effective light area on the plane R _2,5 are overlapped to shorten the length of this optical element in the Z-axis direction. .

Then, the object light beam incident on the second optical element B2 in the Y (-) direction is emitted in the Y (+) direction and is emitted from the third optical element B3.
Incident on.

In the third optical element B3, the object light beam is a convex mirror.
After being reflected in the Z (−) direction by R _3,2 and reflected in the Y (+) direction by the concave mirror R _3,3 at a position where it does not interfere with the first optical element B1, the concave mirror R _3,4 At once, return to the Z (+) direction, and then the convex mirror R
_At the Z position substantially the same as the incident point on _3,2 , it is reflected in the Y (+) direction by the convex mirror R _3,5 , passes through the concave refracting surface R _3,6 and is incident on the fourth optical element B4. To do.

In the fourth optical element B4, the object light beam is a plane mirror R
After being reflected in the Z (−) direction by _{4, 2 , the} light passes through the optical correction plate B5 and forms an image on the image pickup element surface P 1.

First, second and third optical elements B of this embodiment
1, B2, B3 constitute one element of a so-called three-group type zoom lens. Then, the second optical element B2 and the third optical element B3 are relatively moved to change the focal length (imaging magnification) of the photographing optical system.

The zooming operation in this embodiment will be described. At the time of zooming, the first optical element B1, the fourth optical element B4, the optical correction plate B5, and the imaging plane P are fixed, and the second optical element B2 and the third optical element B3 are moved.

The second optical element B2 moves in the Y (-) direction away from the first optical element B1 during zooming from the wide-angle end to the telephoto end.

Therefore, the distance between the optical elements B1 and B2 is widened, but in the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and opposite to each other. Unlike the case of the first embodiment in which the incident reference axis and the emitting reference axis are in the same direction, the distance between the optical elements B2 and B3 should be widened by the same amount as the distance between the optical elements B1 and B2. become.

That is, the moving amount of the second optical element B2 is set to δ
In this case, even if the first optical element B1 and the image plane P 1 are fixed during zooming, the total length of the photographing optical system becomes twice as long as the movement amount δ of the second optical element B2.

FIG. 8 is an optical layout diagram in which each optical element of Example 4 is a single thin lens and the image pickup optical system is developed with respect to its reference axis. The zooming operation will be described below. 8A is a layout drawing of the optical system in the wide-angle end state (W), and FIG. 8B is a layout drawing in the telephoto end state (T).

In the figure, the focal length of the first optical element B1 is f ₁ , the focal length of the second optical element B2 is f ₂ , the focal length of the third optical element B3 is f ₃ , and the fourth optical element B3 is The focal length of element B4
f ₄

When the optical system is at the wide-angle end, the second
The distance from the front focus F ₂ of the optical element B2 to the primary image plane N1 is x _2W (-), the distance from the rear focus F ₂ 'to the secondary image plane N2 is x _2W ', and the third From the front focus F ₃ of the optical element B ₃ to the secondary image plane
The distance to N2 is x _3W (-), the back focal point F ₃ 'to the tertiary image plane
The distance to N3 is x _3W ', the distance from the front focus F _{4 of} the fourth optical element B4 to the tertiary image plane N3 is x ₄ (-), and the distance from the rear focus F ₄ ' to the image plane P is Let the distance be x ₄ '.

Further, the imaging magnification of the second optical element B2 is β _2W ,
The imaging magnification of the third optical element is β _3W , and the imaging magnification of the fourth optical element B4 is β ₄ . (Note that the subscripts _W and _T respectively represent the state at the wide-angle end and the state at the telephoto end of the optical system.) If the Newton's image formation formula holds between each intermediate image formation and image formation plane, The composite magnification β _W of the optical elements behind the optical element B1 of is β _W = β _2W * β _3W * β ₄ = (f ₂ / x _2W ) * (f ₃ / x _3W ) * (f ₄ / x ₄ ) = (F ₂ * f ₃ * f ₄ ) / (x _2W * x _3W * x ₄ ) (11), and the focal length f _W at the wide-angle end is f _W = f ₁ * β _W = (f ₁ It can be expressed as * f ₂ * f ₃ * f ₄ ) / (x _2W * x _3W * x ₄ ) (12).

Here, the secondary image plane N2 generated when the second optical element B2 moves by δ with respect to the first optical element B1.
By moving the third optical element B3 by η so that the position of the tertiary image forming surface N3 is not changed by correcting the position of the final image forming surface P, the focal length is changed. Can be changed.

In the optical arrangement at the telephoto end in FIG. 8B, the image plane P is fixed, so that the first optical element B1, which should have been fixed in the developed view, moves relatively by 2δ. It is illustrated as if it was done.

Since the second optical element B2 has moved by δ with respect to the first optical element B1, the distance x _2T from the primary image plane N1 to the front focal point F _{2 of} the second optical element B2. (-) Becomes x _2T = x _2W −δ (13).

Since the third optical element B3 is moved by η with respect to the tertiary image plane N3, the third optical element B3 moves from the tertiary image plane N3 to the third image plane N3.
'Distance x _3T to' side focal point F ₃ after the optical element B3 _{is, x 3T '= x 3W'} -η = - a ^{_{(f 3 2 / x 3W +}} η) (14).

[0163] Further 'distance x _2T from to the front focal point F ₃ of the third optical element B3' side focal point F ₂ after the second optical element B2 - x _3T
Since the total length of the photographing optical system is longer 2.delta., The _{x 2T '-x 3T = x 2W} ' -x 3W + δ + η = -f 2 2 / x 2W -x 3W + δ + η (15).

X _2T 'and x _3T in the equation (15) are calculated by using the equations (13) and (14) as follows: x _2T ' = -f ₂ ² / x _2T = -f ₂ ² / (x _2W -δ ) (16) x _3T = -f ₃ ² / x _3T '= (f ₃ ² * x _3W ) / (f ₃ ² + x _3W * η) (17) Therefore, the expression (15) is -f ₂ ² / (x _2W −δ) − (f ₃ ² * x _3W ) / (f ₃ ² + x _3W * η) = −f ₂ ² / x _2W −x _3W + δ + η (18) The movement relationship of the third optical element B3 with respect to the movement of the second optical element B2 can be expressed.

Further, the focal length f _T at the telephoto end after the movement of the optical element in this embodiment is β _T = β when the composite magnification β _T of the optical element arranged on the image plane side of the first optical element B1 is _2T * β _3T * β ₄ = (f ₂ / x _2T ) * (f ₃ / x _3T ) * (f ₄ / x ₄ ) = (f ₂ * f ₃ * f ₄ ) / (x _2T * x _3T * x ₄ ) (19), so f _T = f ₁ * β _T = (f ₁ * f ₂ * f ₃ * f ₄ ) / (x _2T * x _3T * x ₄ ) = f ₁ * f ₂ * f ₃ * f ₄ * (f ₃ ² + x _3W * η) / {(x _2W −δ) * f ₃ ² * x _3W * x ₄ } (20).

[0166] zoom ratio Z of this by the photographing optical system _{is, Z = f T / f W} = x 2W * x 3W / (x 2T * x 3T) = x 2W * x 3W * (f 3 2 + x 3W * η) / {(x _2W −δ) * f ₃ ² * x _3W } = x _2W * (f ₃ ² + x _3W * η) / {(x _2W −δ) * f ₃ ² } (21).

In this embodiment, the length of the optical system in the Z direction is remarkably shortened by the structure in which the optical path is effectively folded by each optical element as described above. Further, since the shape of the third optical element B3 is made to fill the dead space behind the first optical element B1, there is no spatial waste in the arrangement of all optical elements.

Furthermore, by making the second optical element B2 and the third optical element B3 move in the Y-axis direction during zooming, the length in the Z-axis direction remains small for all zooming areas. I am sick.

Incidentally, in this embodiment, the reference axis which is incident in the direction of the reference axis A _{4,3 which is} emitted by the fourth optical element B4.
A reference axis that ejects although it is bent 90 ° with respect to the A _{3 and 6} directions
The directions and angles of A ₃ , ₆ are not limited to those described above, and for example, a reflecting surface may be provided and bent in the direction perpendicular to the paper surface (X direction).

Regarding the direction of the reference axis A ₀ incident on the optical system, for example, a 45 ° mirror or the like may be arranged on the object side of the diaphragm B _L so that the reference axis A ₀ is incident perpendicularly to the paper surface. .

Further, in this embodiment, since the first optical element B1 is fixed during zooming, the first optical element B1 and the reflecting surface for bending the incident reference axis may be integrally formed beforehand.

The configuration data is attached to all of the following examples. The fifth to twelfth embodiments are zoom lenses having the same two-group structure as the first embodiment, and the thirteenth to sixteenth embodiments are zoom lenses having the three-group structure including three optical elements.

In these embodiments, the reflecting surface constituting the optical system is a surface having a different curvature in the paper surface and a curvature in a direction perpendicular to the paper surface. In order to prevent vignetting of the mirror optical system, each reflecting mirror is The eccentric aberration caused by the eccentric arrangement is corrected.

Furthermore, by making this reflecting surface a rotationally asymmetric surface, various aberrations are corrected well, and the desired optical performance is achieved in each optical element.

[Embodiment 5] FIG. 9 shows YZ of Embodiment 5 of the present invention.
It is an optical sectional view in a field. The present embodiment is an image pickup optical system of a zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0176]

[Outside 1]

[0177]

[Outside 2] In the present embodiment, the first surface R1 is a diaphragm surface which is an entrance pupil, the second surface R2 to the fifth surface R5, and the sixth surface R6 to the ninth surface R9 are integrated into the first and second optical elements. B1, B2 and the tenth surface R10 are image surfaces.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the first optical element B1. The second surface of the first optical element B1
The light is refracted by R2, reflected by the third surface R3, reflected by the fourth surface R4, refracted by the fifth surface R5, and emitted from the first optical element B1. At this time, a primary image is formed on the intermediate image forming surface near the fourth surface.

Next, the light beam enters the second optical element B2. In the second optical element B2, refraction occurs at the sixth surface R6, seventh surface R7, and eighth surface R8.
Is reflected by, and refracted by the ninth surface R9, and then exits the second optical element B2. At this time, a pupil is formed near the seventh surface in the second optical element B2. Then, the light flux emitted from the second optical element B2 finally forms an image on the tenth surface R10 (imaging surface of an imaging medium such as CCD).

In the present embodiment, the first optical element B1 has the incident reference axis direction and the emitting reference axis direction parallel and in the same direction. In the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and in the same direction.

Next, the zooming action by the movement of each optical element will be described. Upon zooming, the first optical element B1 temporarily moves in the Z plus direction from the wide-angle end to the telephoto end, and then moves to Z
Move in the negative direction. The second optical element B2 moves in the Z minus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, due to zooming from the wide-angle end to the telephoto end, the distance between the first optical element B1 and the second optical element B2 becomes narrower, and the distance between the second optical element B2 and the image plane R10 becomes wider.

10, 11 and 12 are lateral aberration diagrams of this embodiment. These transverse aberration diagrams show that the incident angles of the light flux on this example are (u _Y , u _X ), (0, u _X ), (-u _Y , u _X ), (u _Y , 0), (0 , 0), (-u _Y , 0)
The horizontal aberrations in the Y and X directions are shown for the six light fluxes. The horizontal axis of each lateral aberration diagram is the incident height of the incident light beam in the Y direction and the X direction on the first surface.

FIG. 10 is a lateral aberration diagram at the wide angle end (W) of this embodiment, FIG. 11 is a lateral aberration diagram at the intermediate position (M), and FIG. 12 is at the telephoto end.
It is a lateral-aberration figure of (T).

In this embodiment, as can be seen from the figure, well-balanced aberration correction is obtained in each state.

In this embodiment, the length, width, and thickness of the optical system are 32.9x21.4x6.6 mm, assuming an image size of 4x3 mm.
The size is compact and compact. In particular, in this embodiment, the thickness of each optical element and the entire optical system is small,
Also, since each optical element can be configured by forming a reflecting surface on the side surface of a plate-shaped block, if a mechanism for moving two optical elements along the substrate surface on one substrate is adopted, the overall thin zoom lens Can be easily configured.

[Sixth Embodiment] FIG. 13 shows a sixth embodiment of the present invention.
It is an optical sectional view in the YZ plane. The present embodiment is an image pickup optical system of a zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0187]

[Outside 3]

[0188]

[Outside 4] In the present embodiment, the first surface R1 is a diaphragm surface which is an entrance pupil, the second surface R2 to the fifth surface R5, and the sixth surface R6 to the ninth surface R9 are integrated into the first and second optical elements. B1, B2 and the tenth surface R10 are image surfaces.

The image forming action when the object position is at infinity will be described below. First, the light flux that has passed through the first surface R1 enters the first optical element B1. The second surface of the first optical element B1
The light is refracted by R2, reflected by the third surface R3, reflected by the fourth surface R4, refracted by the fifth surface R5, and emitted from the first optical element B1. At this time, a primary image is formed on the intermediate image forming surface near the fourth surface.

Then, the light beam enters the second optical element B2. In the second optical element B2, refraction occurs at the sixth surface R6, seventh surface R7, and eighth surface R8.
Is reflected by, and refracted by the ninth surface R9, and then exits the second optical element B2. At this time, a pupil is formed near the seventh surface in the second optical element B2. Then, the light flux emitted from the second optical element B2 finally forms an image on the tenth surface R10 (imaging surface of an imaging medium such as CCD).

In this embodiment, the first optical element B1 has the incident reference axis direction and the emitting reference axis direction parallel and in the same direction. Unlike the fifth embodiment, the second optical element B2 has an incident reference axis direction and an outgoing reference axis direction that are parallel and opposite to each other.

Next, the zooming effect by the movement of each optical element will be described. Upon zooming, the first optical element B1 moves in the Z plus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, due to zooming from the wide-angle end to the telephoto end, the distance between the first optical element B1 and the second optical element B2 becomes narrower, and the distance between the second optical element B2 and the image plane R10 becomes wider. In this embodiment, the entrance / exit reference axes of the second optical element B2 are opposite to those of the fifth embodiment, and therefore, this embodiment is more compact than the fifth embodiment when the entire variable power range is compared. There is.

14, 15, and 16 are lateral aberration diagrams of this embodiment.

[Seventh Embodiment] FIG. 17 shows a seventh embodiment of the present invention.
It is an optical sectional view in the YZ plane. The present embodiment is an image pickup optical system of a zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0195]

[Outside 5]

[0196]

[Outside 6] In the present embodiment, the first surface R1 is a diaphragm surface which is an entrance pupil, the second surface R2 to the fifth surface R5, and the sixth surface R6 to the ninth surface R9 are integrated into the first and second optical elements. B1, B2 and the tenth surface R10 are image surfaces.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the first optical element B1. The second surface of the first optical element B1
The light is refracted by R2, reflected by the third surface R3, reflected by the fourth surface R4, refracted by the fifth surface R5, and emitted from the first optical element B1. At this time, a primary image is formed on the intermediate image forming surface near the fifth surface.

Next, the light beam enters the second optical element B2. In the second optical element B2, refraction occurs at the sixth surface R6, seventh surface R7, and eighth surface R8.
Is reflected by, and refracted by the ninth surface R9, and then exits the second optical element B2. At this time, a pupil is formed near the seventh surface. Then, the light flux emitted from the second optical element B2 is the tenth surface R10 (CC
The final image is formed on the image pickup surface of the image pickup medium such as D.

In the present embodiment, the first optical element B1 has the incident reference axis direction and the emitting reference axis direction parallel and opposite to each other. In the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and in the same direction.

Next, the zooming action by the movement of each optical element will be described. At the time of zooming, the first optical element B1 moves in the Z minus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, the distance between the first optical element B1 and the second optical element B2 is narrowed due to the zooming from the wide-angle end to the telephoto end,
The space between the second optical element B2 and the image plane R10 widens.

18, 19, and 20 are lateral aberration diagrams of this embodiment.

[Embodiment 8] FIG. 21 shows an embodiment 8 of the present invention.
It is an optical sectional view in the YZ plane. The present embodiment is an image pickup optical system of a zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0203]

[Outside 7]

[0204]

[Outside 8] In the present embodiment, the first surface R1 is a diaphragm surface which is an entrance pupil, the second surface R2 to the fifth surface R5, and the sixth surface R6 to the ninth surface R9 are integrated into the first and second optical elements. B1, B2 and the tenth surface R10 are image surfaces.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the first optical element B1. The second surface of the first optical element B1
The light is refracted by R2, reflected by the third surface R3, reflected by the fourth surface R4, refracted by the fifth surface R5, and emitted from the first optical element B1. At this time, a primary image is formed on the intermediate image forming surface near the fourth surface.

Next, the light beam enters the second optical element B2. In the second optical element B2, refraction occurs at the sixth surface R6, seventh surface R7, and eighth surface R8.
Is reflected by, and refracted by the ninth surface R9, and then exits the second optical element B2. At this time, a pupil is formed near the seventh surface. Then, the light flux emitted from the second optical element B2 is the tenth surface R10 (CC
The final image is formed on the image pickup surface of the image pickup medium such as D.

In the present embodiment, the first optical element B1 has an incident reference axis direction and an outgoing reference axis direction which are parallel and opposite to each other. Further, in the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and opposite to each other.

Next, the zooming action by the movement of each optical element will be described. At the time of zooming, the first optical element B1 moves in the Z minus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z minus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, due to zooming from the wide-angle end to the telephoto end, the distance between the first optical element B1 and the second optical element B2 becomes narrower, and the distance between the second optical element B2 and the image plane R10 becomes wider.

22, 23 and 24 are lateral aberration diagrams of this embodiment.

The ninth to twelfth embodiments are two-group type zoom lenses similar to the fifth to eighth embodiments, but in the conventional ones, each optical element is provided with a curved reflecting surface on the surface of a block such as transparent plastics or glass. The light rays from the object were repeatedly reflected and transmitted through this block. However, in the following Examples 9 to 12, all the decentered reflecting surfaces constituting each group are surface mirrors made of plastics, glass, metal, etc.,
Each of the two surface mirrors constituting each group is connected outside the optical path and integrated.

[Ninth Embodiment] FIG. 25 shows a ninth embodiment of the present invention.
It is an optical sectional view in YZ. The present embodiment is an image pickup optical system of a two-group zoom lens having a zoom ratio of about 1.5. The constitutional data will be described below.

[0212]

[Outside 9]

[0213]

[Outside 10] In this embodiment, the first surface R1 is a diaphragm surface that is an entrance pupil. The second surface R2 and the third surface R3, which are reflective surfaces, and the fourth surface R4 and the fifth surface
The surface R5 is formed by connecting the side surfaces of the surface mirrors to form one body, forming first and second optical elements B1 and B2. The sixth surface R6 is the image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the portion of the first optical element B1. Here, the second surface R2, the third
It reflects off surface R3 and exits the portion of the first optical element B1. At this time, the primary image is formed on the intermediate image forming surface near the third surface.

Next, the light beam enters the portion of the second optical element B2.
Here, the light is reflected by the fourth surface R4 and the fifth surface R5, and the second optical element B2
Leave the part. At this time, a pupil is formed near the fourth surface. Then, the light flux emitted from the second optical element B2 is the sixth surface
The final image is formed on R6 (the image pickup surface of the image pickup medium such as CCD).

In this embodiment, the first optical element B1 has an incident reference axis direction and an outgoing reference axis direction which are parallel and in the same direction. In the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and in the same direction.

Next, the zooming action by the movement of each optical element will be described. Upon zooming, the first optical element B1 moves in the Z plus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z minus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, the distance between the first optical element B1 and the second optical element B2 is narrowed due to the zooming from the wide-angle end to the telephoto end,
The space between the second optical element B2 and the image plane R10 widens.

26, 27 and 28 are lateral aberration diagrams of this embodiment.

[Embodiment 10] FIG. 29 shows Embodiment 1 of the present invention.
It is an optical sectional view in the YZ plane of 0. In this embodiment, the zoom ratio is approximately
It is an image pickup optical system of a 1.5 × 2 group zoom lens). The constitutional data will be described below.

[0220]

[Outside 11]

[0221]

[Outside 12] In this embodiment, the first surface R1 is a diaphragm surface that is an entrance pupil. The second surface R2 and the third surface R3, which are reflecting surfaces, are formed by connecting the side surfaces of the respective surface mirrors to form a first optical element B1. The fourth surface R4 and the fifth surface R5, which are reflecting surfaces, are formed on the integrated second optical element B2. The sixth surface R6 is the image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the portion of the first optical element B1. Second in the first optical element B1
The light is reflected by the surface R2 and the third surface R3, and leaves the portion of the first optical element B1. At this time, the primary image is formed on the intermediate image forming surface near the third surface.

Next, the light beam enters the portion of the second optical element B2.
The second optical element B2 reflects on the fourth surface R4 and the fifth surface R5,
Exit the optical element B2 part. At this time, a pupil is formed near the fourth surface. Then, the light flux emitted from the portion of the second optical element B2 finally forms an image on the sixth surface R6 (the image pickup surface of the image pickup medium such as CCD).

In the present embodiment, the first optical element B1 has the incident reference axis direction and the emitting reference axis direction parallel and in the same direction. Further, in the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and opposite to each other.

Next, the zooming effect by the movement of each optical element will be described. Upon zooming, the first optical element B1 moves in the Z plus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, due to zooming from the wide-angle end to the telephoto end, the distance between the first optical element B1 and the second optical element B2 becomes narrower, and the distance between the second optical element B2 and the image plane R10 becomes wider.

30, 31, and 32 are lateral aberration diagrams of this embodiment.

[Embodiment 11] FIG. 33 shows Embodiment 1 of the present invention.
2 is an optical cross-sectional view in the YZ plane of FIG. In this embodiment, the zoom ratio is approximately
This is an image pickup optical system for a 1.5x 2 group zoom lens. The constitutional data will be described below.

[0228]

[Outside 13]

[0229]

[Outside 14] In this embodiment, the first surface R1 is a diaphragm surface that is an entrance pupil. The second surface R2 and the third surface R3, which are reflective surfaces, are the first optical element.
Formed on B1. 4th surface R4 and 5th surface which are reflective surfaces
R5 connects the side surfaces of the surface mirrors respectively, and becomes an integral unit.
Optical element B2 is formed. The sixth surface R6 is the image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the portion of the first optical element B1. Here, the second surface R2, the third
It reflects off surface R3 and exits the portion of the first optical element B1. At this time, the primary image is formed on the intermediate image forming surface near the third surface.

Next, the light beam enters the portion of the second optical element B2.
Here, the light is reflected by the fourth surface R4 and the fifth surface R5, and the second optical element B2
Leave the part. At this time, a pupil is formed near the fourth surface. Then, the light flux emitted from the second optical element B2 is the sixth surface
An image is finally formed on R6 (the image pickup surface of an image pickup medium such as CCD).

In the present embodiment, the first optical element B1 has an incident reference axis direction and an outgoing reference axis direction which are parallel and opposite to each other. In the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and in the same direction.

Next, the zooming action by the movement of each optical element will be described. At the time of zooming, the first optical element B1 moves in the Z minus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, the distance between the first optical element B1 and the second optical element B2 is narrowed due to the zooming from the wide-angle end to the telephoto end,
The space between the second optical element B2 and the image plane R10 widens.

34, 35 and 36 are lateral aberration diagrams of this embodiment.

[Embodiment 12] FIG. 37 shows Embodiment 1 of the present invention.
2 is an optical cross-sectional view in the YZ plane of 2. FIG. In this embodiment, the zoom ratio is approximately
This is an image pickup optical system for a 1.5x 2 group zoom lens. The constitutional data will be described below.

[0236]

[Outside 15]

[0237]

[Outside 16] In this embodiment, the first surface R1 is a diaphragm surface that is an entrance pupil. The second surface R2 and the third surface R3, and the fourth surface R4 and the fifth surface R5 are surface mirrors formed on the first and second optical elements B1 and B2, respectively. The sixth surface R6 is the image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 enters the portion of the first optical element B1. Here, the second surface R2, the third
It reflects off surface R3 and exits the portion of the first optical element B1. At this time, the primary image is formed on the intermediate image forming surface near the third surface.

Next, the light beam enters the portion of the second optical element B2.
Here, the light is reflected by the fourth surface R4 and the fifth surface R5, and the second optical element B2
Leave the part. At this time, a pupil is formed near the fourth surface. Then, the light flux emitted from the second optical element B2 is the sixth surface R6.
The final image is formed on the (imaging surface of the imaging medium such as CCD).

In the present embodiment, the first optical element B1 has the incident reference axis direction and the emitting reference axis direction parallel and opposite to each other. Further, in the second optical element B2, the direction of the incident reference axis and the direction of the exit reference axis are parallel and opposite to each other.

Next, the zooming effect by the movement of each optical element will be described. At the time of zooming, the first optical element B1 moves in the Z minus direction from the wide-angle end to the telephoto end. The second optical element B2 moves in the Z minus direction from the wide-angle end to the telephoto end. The tenth surface R10, which is the image surface, does not move during zooming. Then, due to zooming from the wide-angle end to the telephoto end, the distance between the first optical element B1 and the second optical element B2 becomes narrower, and the distance between the second optical element B2 and the image plane R10 becomes wider.

38, 39 and 40 are lateral aberration diagrams of this embodiment.

Examples 13 to 16 are examples of so-called three-group zoom lenses.

[Embodiment 13] FIG. 41 shows Embodiment 1 of the present invention.
3 is an optical cross-sectional view in the YZ plane of FIG. The present embodiment is an image pickup optical system of a three-group zoom lens having a zoom ratio of about 2 times. Also, FIG.
2 is a perspective view of the present embodiment. The constitutional data will be described below.

[0245]

[Outside 17]

[0246]

[Outside 18]

[0247]

[Outside 19] In FIG. 41, the first surface is the diaphragm surface R1 which is the entrance pupil, and the second surface R2 to the seventh surface R7, the eighth surface R8 to the thirteenth surface R13, and the fourteenth surface R14 to the nineteenth surface R19 are respectively integrated. Are the first, second and third optical elements, and the twentieth surface R20 is the image plane.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the diaphragm R1 enters the first optical element B1. In the first optical element B1, refraction at the second surface R2, reflection at the third surface R3, total reflection at the fourth surface R4, fifth surface R5, reflection at the sixth surface R6, refraction at the seventh surface R7, The first optical element B1 is emitted. Here, the second surface R2 and the fourth surface R4 are the same surface and serve both as a refraction surface and a total reflection surface. The same applies to the fifth surface R5 and the seventh surface R7. Also, the luminous flux is on the fourth surface R4 and the fifth surface R5.
An intermediate image is formed between.

Next, the light beam enters the second optical element B2.
In the second optical element B2, the light is refracted by the eighth surface R8, reflected by the ninth surface R9, totally reflected by the tenth surface R10, and eleventh surface R11, and twelfth surface R1.
It reflects at 2, refracts at the 13th surface R13, and exits the second optical element B2. Here, the eighth surface R8 and the tenth surface R10 are the same surface and serve both as a refracting surface and a total reflection surface. 11th surface R11 and 1st
The same applies to R3 on the third side. Further, the light flux forms an intermediate image near the twelfth surface.

Next, the light beam enters the third optical element B3.
In the third optical element B3, refraction occurs on the 14th surface R14, and the 15th surface
The light is reflected by R15, totally reflected by the sixteenth surface R16, totally reflected by the seventeenth surface R17, reflected by the eighteenth surface R18 and refracted by the nineteenth surface R19, and emitted from the third optical element B3. 14th surface R14 and 16th surface R16
Is the same surface and serves both as a refraction surface and a total reflection surface. Seventeenth
The same applies to the surface R17 and the nineteenth surface R19. Also, the luminous flux is the first
An intermediate image is formed between the sixth surface R16 and the seventeenth surface R17.

Finally, the light flux emitted from the third optical element B3 forms an image on the final image formation surface twentieth surface R20 (the image pickup surface of an image pickup medium such as CCD).

Next, the movement of each optical element associated with the zooming operation will be described. During zooming, the first optical element B1 is fixed and does not move. The second optical element B2 moves back and forth along a convex locus in the Z plus direction from the wide-angle end to the telephoto end. The third optical element B3 moves in the Z minus direction from the wide-angle end to the telephoto end. The twentieth surface R20, which is the image plane, does not move during zooming.

It should be noted that the optical path length of the entire system from the first surface R1 to the image surface R20 during zooming from the wide-angle end to the telephoto end is constant.

In the present embodiment, the incident / exit reference axes of the three optical elements are parallel and in the same direction.

43, 44 and 45 are lateral aberration diagrams of this embodiment. In this embodiment, as can be seen from the figure, well-balanced aberration correction is obtained at each focal length.

Further, in this embodiment, assuming that the image size is 8x6 mm, the length, width and thickness of the optical system are about 65.8x37x11.4 mm.
It has become a degree. As in the previous embodiments, the thickness of the optical system is small, and since each reflecting surface can be configured as an optical element formed on the side surface of a plate-shaped block as shown in FIG. By mounting one optical element and moving two of the optical elements along the substrate surface, a thin zoom lens as a whole can be easily configured.

[Embodiment 14] FIG. 46 shows Embodiment 1 of the present invention.
4 is an optical cross-sectional view in the YZ plane of FIG. The present embodiment is an image pickup optical system of a three-group zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0258]

[Outside 20]

[0259]

[Outside 21]

[0260]

[Outside 22] In FIG. 46, the first surface is the diaphragm surface R1 which is the entrance pupil, and the second surface R2 to the seventh surface R7, the eighth surface R8 to the thirteenth surface R13, and the fourteenth surface R14 to the eighteenth surface R18 are respectively integrated. Are the first, second, and third optical elements, and the nineteenth surface R19 is an image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the diaphragm R1 enters the first optical element B1. In the first optical element B1, refraction at the second surface R2, reflection at the third surface R3, total reflection at the fourth surface R4, fifth surface R5, reflection at the sixth surface R6, refraction at the seventh surface R7, The first optical element B1 is emitted. Here, the second surface R2 and the fourth surface R4 are the same surface and serve both as a refraction surface and a total reflection surface. The same applies to the fifth surface R5 and the seventh surface R7. Also, the luminous flux is on the fourth surface R4 and the fifth surface R5.
An intermediate image is formed between.

Next, the light beam enters the second optical element B2.
In the second optical element B2, the light is refracted by the eighth surface R8, reflected by the ninth surface R9, totally reflected by the tenth surface R10, and eleventh surface R11, and twelfth surface R1.
It reflects at 2, refracts at the 13th surface R13, and exits the second optical element B2. Here, the eighth surface R8 and the tenth surface R10 are the same surface and serve both as a refracting surface and a total reflection surface. 11th surface R11 and 1st
The same applies to R3 on the third side. Further, the light flux forms an intermediate image near the twelfth surface. In addition, the luminous flux is generated by the second optical element B2 and the third optical element.
A pupil is formed with the optical element B3.

Next, the light beam enters the third optical element B3.
In the third optical element B3, refraction occurs on the 14th surface R14, and the 15th surface
The light is reflected by R15, totally reflected by the sixteenth surface R16, reflected by the seventeenth surface R17, and refracted by the eighteenth surface R18, and is emitted from the third optical element B3. Here, the fourteenth surface R14, the sixteenth surface R16, and the eighteenth surface R18 are the same surface and serve both as a refraction surface and a total reflection surface.

Finally, the light flux emitted from the third optical element B3 forms an image on the final image plane 19th surface R19 (image pickup surface of an image pickup medium such as CCD).

Next, the movement of each optical element associated with the zooming operation will be described. During zooming, the first optical element B1 is fixed and does not move. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. Third optical element B3
Moves in the Z plus direction from the wide-angle end to the telephoto end.
The nineteenth surface, which is the image surface, does not move during zooming.

Here, the distance between the first optical element B1 and the second optical element B2 is widened due to the magnification change from the wide-angle end to the telephoto end, and the second optical element B2 and the third optical element B3 are expanded. The distance between and becomes narrower, and the distance between the third optical element B3 and the image plane R19 becomes wider. Also, from the wide-angle end to the telephoto end, from the first surface R1 to the image plane
The optical path length of the entire system between R19 is changing to be long.

In this embodiment, the entrance / exit reference axes of the first optical element B1 are parallel and oriented in opposite directions, and the entrance / exit reference axes of the second and third optical elements B2, B3 are both parallel. It is the same direction.

47, 48 and 49 are lateral aberration diagrams of this embodiment.

[Embodiment 15] FIG. 50 shows Embodiment 1 of the present invention.
5 is an optical cross-sectional view in the YZ plane of FIG. The present embodiment is an image pickup optical system of a three-group zoom lens having a zoom ratio of about 2 times. The constitutional data will be described below.

[0270]

[Outside 23]

[0271]

[Outside 24]

[0272]

[Outside 25] In FIG. 50, the first surface R1 is the diaphragm surface which is the entrance pupil, and the second surface
Surface R2 to sixth surface R6, seventh surface R7 to eleventh surface R11, twelfth surface R1
The second to sixteenth surfaces R16 are integrated first, second and third optical elements, and the seventeenth surface R17 is an image surface.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the first surface R1 is incident on the first optical element B1. In the first optical element B1, refraction on the second surface R2, reflection on the third surface R3, total reflection on the fourth surface R4,
The first optical element B1 reflects on the fifth surface R5 and refracts on the sixth surface R6.
Inject. Here, the second surface R2, the fourth surface R4, and the sixth surface R6 are the same surface and serve both as a refraction surface and a total reflection surface. Also, the first
The optical element B1 has an intermediate image plane in the vicinity of the fifth surface R5.

Then, the light flux emitted from the first optical element B1 enters the second optical element B2. In the second optical element B2, the light is refracted by the seventh surface R7, reflected by the eighth surface R8, totally reflected by the ninth surface R9, reflected by the tenth surface R10, and refracted by the eleventh surface R11. Eject B2. Here, 7th surface R7, 9th surface R9, 11th surface
The surface R11 is the same surface and serves both as a refracting surface and a total reflection surface.

Then, the light flux emitted from the second optical element B2 enters the third optical element B3. In the third optical element B3, the twelfth surface R12 refracts, the thirteenth surface R13 reflects, and the fourteenth surface R14.
The light is totally reflected by, the light is reflected by the fifteenth surface R15, the light is refracted by the sixteenth surface R16, and the third optical element B3 is emitted. Here the 12th surface R12
The fourteenth surface R14 and the sixteenth surface R16 are the same surface and serve both as a refraction surface and a total reflection surface.

Finally, the light flux emitted from the third optical element B3 forms an image on the final image forming surface 17th surface R17 (image pickup surface of an image pickup medium such as CCD).

Next, the movement of each optical element associated with the zooming operation will be described. The first optical element B1 is fixed and does not move during zooming. The second optical element B2 moves in the Z plus direction from the wide-angle end to the telephoto end. Third optical element
B3 also moves in the Z plus direction from the wide-angle end to the telephoto end. The seventeenth surface, which is the image surface, does not move during zooming.

Here, the distance between the first optical element B1 and the second optical element B2 becomes narrower due to the zooming from the wide-angle end to the telephoto end, and the distance between the second optical element B2 and the third optical element B3 becomes smaller. The distance becomes narrower and the distance between the third optical element B3 and the image plane becomes wider. Also,
From the wide-angle end to the telephoto end, the optical path length of the entire system from the first surface R1 to the image surface R17 changes so as to become shorter.

In this embodiment, the entrance and exit reference axes of the three optical elements are parallel to each other and oriented in opposite directions.

51, 52 and 53 are lateral aberration diagrams of the present embodiment.

[Embodiment 16] FIG. 54 shows Embodiment 1 of the present invention.
FIG. 6 is an optical cross-sectional view in the YZ plane of No. 6; In this embodiment, the zoom ratio is approximately
It is an imaging optical system of a 2.9x three-group zoom lens. The constitutional data is shown below.

[0282]

[Outside 26]

[0283]

[Outside 27]

[0284]

[Outside 28]

[0285]

[Outside 29] In FIG. 54, the first surface is the diaphragm surface R1 which is the entrance pupil, and the second surface R2 to the eighth surface R8, the ninth surface R9 to the fifteenth surface R15, and the sixteenth surface R16 to the twenty second surface R22 are respectively integrated. The 23rd surface R23 is the image plane.

The image forming action when the object position is set to infinity will be described below. First, the light flux that has passed through the diaphragm R1 enters the first optical element B1. In the first optical element B1, refraction occurs at the second surface R2, third surface R3, fourth surface R4, fifth surface R5, sixth surface
The light is reflected by R6 and the seventh surface R7, refracted by the eighth surface R8, and emitted from the first optical element B1. Here, the light flux forms an intermediate image near the fourth surface R4. Further, a secondary image is formed between the first optical element B1 and the second optical element B2.

Next, the light beam enters the second optical element B2.
In the second optical element B2, the light is refracted by the ninth surface R9 and the eleventh surface R11.
, The twelfth surface R12, the thirteenth surface R13, and the fourteenth surface R14 are reflected, and the fifteenth surface R15 is refracted, and the second optical element B2 is emitted. Here, the light flux has an intermediate image plane between the twelfth surface R12 and the thirteenth surface R13. Further, the light flux forms a pupil near the 15th surface R15.

Then, the luminous flux emitted from the second optical element B2 enters the third optical element B3. In the third optical element B3, refraction occurs on the 16th surface R16, 17th surface R17, 18th surface R18, 1st surface
Reflected on 9th surface R19, 20th surface R20, 21st surface R21, 22nd surface
The light is refracted at the surface R22 and emerges from the third optical element B3. Here, the light flux forms an intermediate image near the eighteenth surface R18.

Finally, the light flux emitted from the third optical element B3 forms an image on the 23rd surface R23 (the image pickup surface of the image pickup medium such as CCD) which is the final image pickup surface.

Next, the movement of each optical element due to the zooming operation will be described. The first optical element B1 is fixed and does not move during zooming. The second optical element B2 moves in the Z minus direction from the wide-angle end to the telephoto end. Third optical element
B3 moves in the Z minus direction from the wide-angle end to the telephoto end. The twentieth surface R20, which is the image plane, does not move during zooming.

Here, the distance between the first optical element B1 and the second optical element B2 is narrowed due to the zooming from the wide-angle end to the telephoto end, and the second optical element B2 and the third optical element B3 are narrowed. The distance between and increases, and the distance between the third optical element B3 and the image plane R23 increases. Also, from the wide-angle end to the telephoto end, from the first surface R1 to the image plane
The optical path length of the entire system between R23 is changing to be long.

In this embodiment, the reference axes of incidence and emission of the three optical elements are parallel and opposite to each other.

55, 56 and 57 are lateral aberration diagrams of this embodiment.

Further, in the present invention, an optical element in which two refracting surfaces and a plurality of reflecting surfaces are formed on the surface of the transparent body which constitutes Examples 5-8 and Examples 13-16, and Examples 9--9.
Zooming is performed by using a plurality of optical elements integrally forming a plurality of reflecting surfaces composed of surface reflecting mirrors that constitute 12 and changing the relative position of at least two of the optical elements. A reflective zoom optical system can also be configured. Even in that case, effects such as grading the arrangement accuracy (assembly accuracy) of the reflection mirrors can be obtained.

Of the above examples, Examples 1 to 8 and Examples 13 to 16 are all optical in which two refracting surfaces and a plurality of reflecting surfaces such as curved surfaces and flat surfaces are formed on the side surface of a thin plate-shaped block. It has an element, and zooming is performed by moving two of these optical elements relative to the image plane.

In all the examples, the curved reflecting surfaces formed on the optical element are all decentered curved reflecting surfaces, and all of them are decentered in one plane (YZ). Then, the two optical elements move in one direction parallel to the YZ plane to change the magnification.

According to the present invention, the optical system can be constructed with a thin optical element, and the zoom structure can be moved on one plane, so that a thin zoom lens can be easily constructed.

Furthermore, since the direction of the reference axis emitted from each optical element can be easily set to the same direction or the opposite direction to the direction of the incident reference axis, the degree of freedom in setting the overall shape of the optical system is increased. It is very large and therefore gives great freedom to the morphology of the camera.

In all cases, well-balanced aberration correction is obtained at each focal length.

Further, in the present invention, the above-mentioned Example 13 is used.
In the form of a camera, by arranging the incident reference axis of the fixed optical element (first optical element B1) at the time of zooming at an arbitrary angle with respect to the moving plane of the optical element that moves at the time of zooming like It is possible to increase the degree of freedom.

FIG. 58 shows a second example in which the incident reference axis of the optical element (first optical element B1) that does not move during zooming moves during zooming.
It is a perspective view of the optical system inclined at an arbitrary angle with respect to the moving plane of the third optical element. In the figure, B1 is a first optical element that does not move during zooming, and corresponds to the so-called front lens of a so-called photographing optical system. B2 and B3 are second and third optical elements that move during zooming, respectively. The second optical element B2 corresponds to a so-called variator, and the third optical element B3 corresponds to a compensator.

The second and third optical elements B2 and B3 are shown in FIG.
Move on the YZ plane of 8 to change the magnification. Further, all the reference axes in the second and third optical elements B2 and B3 are on the YZ plane.

Second and third optical elements B that move during zooming
For 2 and B3, the YZ plane and the plane including the reference axis cannot be tilted for the above reasons. However, when changing the magnification, the first fixed
In the optical element B1 of the above, a part of the reference axis (A _{1,2 to} A _1,6 ) in the optical element B1 must exist in the reference axis plane, but the other part of the reference axis (A ₀ , A _{1 , 1} ) is the reference axis plane (moving plane)
It doesn't have to be inside.

That is, in the present embodiment, the reflecting surface R _1,2 is provided, and the direction of the reference axis A _{0 which is} incident from the X-axis direction is controlled by the surface R _1,2 in the first optical element B ₁ by the Z-axis. Biased in the direction.

By providing the reflecting surfaces R ₁ , ₂ in this way, the direction of the light beam incident on the photographing optical system can be freely set, and the degree of freedom in the form of the camera can be further increased.

[0306]

According to the present invention, by setting each element as described above, in particular, a plurality of optical elements integrally formed with a plurality of curved or flat reflecting surfaces are used, and at least one of the plurality of optical elements is used. By appropriately changing the relative position of the two optical elements to perform zooming, the overall size of the mirror optical system can be reduced, and the accuracy of the reflective mirror arrangement (assembly accuracy), which is often present in mirror optical systems, can be moderated. The reflective zoom optical system and the image pickup apparatus using the same can be achieved.

In addition, the diaphragm is arranged on the most object side of the optical system, and the object image is formed at least once in the optical system, so that the wide-angle reflective zoom optical system is provided. However, by reducing the effective diameter of the optical system, and by providing an appropriate refracting power to a plurality of reflecting surfaces forming the optical element and arranging the reflecting surfaces forming each optical element eccentrically, It is possible to achieve a reflective zoom optical system in which the optical path in the system is bent into a desired shape and the overall length of the optical system in a predetermined direction is shortened, and an image pickup apparatus using the same.

In addition, according to the present invention, (2-1) In an optical system having a plurality of optical elements integrally formed with a plurality of reflecting surfaces having a curvature, the relative positions of the plurality of optical elements are changed. , By configuring the optical system to perform zooming and focusing, the reflecting surface that moves during zooming is unitized, so it is the most effective compared to zooming operations in conventional mirror optical systems. Since it is possible to guarantee the relative positional accuracy of each reflecting surface that requires accuracy, it is possible to prevent deterioration of optical performance due to zooming. (2-2) Since the optical element itself has the reflecting surface, the optical element itself functions as a lens barrel.
A mounting member that is significantly simpler than a conventional lens barrel is sufficient. (2-3) As compared with the refracting lens system, since each optical element is a lens unit in which a plurality of surfaces having a curvature are integrally formed, it is possible to reduce the number of parts of the entire imaging system. Therefore, it is possible to reduce the cost of the imaging system in terms of the number of parts.

Furthermore, since the number of parts of the entire image pickup system can be reduced, it is possible to reduce the cumulative error due to the attachment of the parts and prevent the deterioration of the optical performance. (2-4) By eccentrically arranging each reflecting surface on the optical element at an appropriate position, it is possible to bend the optical path in the optical system into a desired shape and to shorten the optical system in the entire length direction. (2-5) By providing a fixed optical element during zooming, a part of the reference axis can be tilted at an arbitrary angle with respect to a plane including most of the reference axis, and the degree of freedom in the form of the camera can be increased. I can. (2-6) By adopting a configuration in which an object image is transmitted by repeating image formation a number of times, the effective light diameter of each surface is suppressed to a small size, and the entire photographing optical system is made compact. (2-7) By setting the image forming size of the intermediate image forming surface to be relatively smaller than the image pickup element surface size, it is possible to suppress the effective ray diameter of each surface when transmitting the object image. (2-8) By setting a plane in which the optical element moves parallel to a plane including most of the reference axes, including the reference axis in the two optical elements that change the relative position, the optical element can be changed in magnification. Even if it moves, the parallelism between the plane including the reference axis and the plane on which each optical element moves can be easily maintained. Therefore, the occurrence of decentering aberration caused by the inclination between the moving plane of the optical element that moves during zooming and the plane including the reference axis is eliminated. (2-9) Since the movement of each optical element during zooming is performed on one plane, parallel decentering in the direction perpendicular to the moving direction can be easily prevented. In principle, rotation in the plane perpendicular to the moving plane can be eliminated. (2-10) Since each optical element is arranged on one plane, each optical element can be incorporated from one direction,
Assembling becomes easy and the assembling cost can be reduced. (2-11) By arranging the diaphragm arranged in the optical system on the object side of the optical system, it is possible to achieve a zoom lens in which the lens diameter does not increase even if the angle of view of the optical system is widened. It is possible to achieve a reflective zoom optical system having at least one of the above effects and an image pickup apparatus using the same.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a coordinate system according to an embodiment of the present invention.

FIG. 2 is a schematic view of a main part of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram for explaining a scaling operation of the first embodiment.

FIG. 4 is a schematic view of the essential portions of Embodiment 2 of the present invention.

FIG. 5 is a schematic view of the essential portions of Embodiment 3 of the present invention.

FIG. 6 is an explanatory diagram for explaining a zooming operation of the third embodiment.

FIG. 7 is a schematic view of the essential portions of Embodiment 4 of the present invention.

FIG. 8 is an explanatory diagram for explaining a zooming operation of the fourth embodiment.

FIG. 9 is an optical cross-sectional view in the YZ plane of Example 5 of the present invention.

FIG. 10 is a lateral aberration diagram for Example 5 (wide-angle end).

FIG. 11 is a lateral aberration diagram of Example 5 (intermediate position).

FIG. 12 is a lateral aberration diagram for Example 5 (telephoto end).

FIG. 13 is an optical cross-sectional view in the YZ plane of Example 6 of the present invention.

FIG. 14 is a lateral aberration diagram for Example 6 (wide-angle end).

FIG. 15 is a lateral aberration diagram of Example 6 (intermediate position).

FIG. 16 is a lateral aberration diagram for Example 6 (telephoto end).

FIG. 17 is an optical sectional view in the YZ plane of Example 7 of the present invention.

FIG. 18 is a lateral aberration diagram for Example 7 (wide-angle end).

FIG. 19 is a lateral aberration diagram for Example 7 (intermediate position).

FIG. 20 is a lateral aberration diagram of Example 7 (telephoto end).

FIG. 21 is an optical cross-sectional view in the YZ plane of Example 8 of the present invention.

FIG. 22 is a lateral aberration diagram of Example 8 (wide-angle end).

FIG. 23 is a lateral aberration diagram for Example 8 (intermediate position).

FIG. 24 is a lateral aberration diagram for Example 8 (telephoto end).

FIG. 25 is an optical cross-sectional view in the YZ plane of Example 9 of the present invention.

FIG. 26 is a lateral aberration diagram for Example 9 (wide-angle end).

FIG. 27 is a lateral aberration diagram for Example 9 (intermediate position).

28 is a lateral aberration diagram for Example 9 (telephoto end). FIG.

FIG. 29 is an optical cross-sectional view in the YZ plane of Example 10 of the present invention.

FIG. 30 is a lateral aberration diagram for Example 10 (wide-angle end).

FIG. 31 is a lateral aberration diagram for Example 10 (intermediate position).

FIG. 32 is a lateral aberration diagram of Example 10 (telephoto end).

FIG. 33 is an optical cross-sectional view in the YZ plane of Example 11 of the present invention.

34 is a lateral aberration diagram for Example 11 (wide-angle end). FIG.

FIG. 35 is a lateral aberration diagram for Example 11 (intermediate position).

FIG. 36 is a lateral aberration diagram for Example 11 (at the telephoto end).

FIG. 37 is an optical cross-sectional view in the YZ plane of Example 12 of the present invention.

FIG. 38 is a lateral aberration diagram (wide-angle end) of Example 12;

FIG. 39 is a lateral aberration diagram of Example 12 (intermediate position).

40 is a lateral aberration diagram for Example 12 (telephoto end). FIG.

FIG. 41 is an optical cross-sectional view in the YZ plane of Example 13 of the present invention.

42 is a perspective view of Example 13. FIG.

43 is a lateral aberration diagram for Example 13 (wide-angle end). FIG.

FIG. 44 is a lateral aberration diagram of Example 13 (intermediate position).

FIG. 45 is a lateral aberration diagram of Example 13 (telephoto end).

FIG. 46 is an optical cross-sectional view in the YZ plane of Example 14 of the present invention.

FIG. 47 is a lateral aberration diagram for Example 14 (wide-angle end).

FIG. 48 is a lateral aberration diagram of Example 14 (intermediate position).

FIG. 49 is a lateral aberration diagram of Example 14 (telephoto end).

FIG. 50 is an optical cross-sectional view in the YZ plane of Example 15 of the present invention.

51 is a lateral aberration diagram of Example 15 (wide-angle end). FIG.

FIG. 52 is a lateral aberration diagram of Example 15 (intermediate position).

FIG. 53 is a lateral aberration diagram of Example 15 (telephoto end).

FIG. 54 is an optical cross-sectional view in the YZ plane of Example 16 of the present invention.

FIG. 55 is a lateral aberration diagram for Example 16 (wide-angle end).

FIG. 56 is a lateral aberration diagram of Example 16 (intermediate position).

FIG. 57 is a lateral aberration diagram of Example 16 (telephoto end).

FIG. 58 shows the incident reference axis as YZ in the third group zoom lens.
Perspective view of an optical system tilted at an arbitrary angle to the plane

FIG. 59 is a basic configuration diagram of a Cassegrain type reflecting telescope.

FIG. 60 is an explanatory diagram of a first method of preventing the vignetting by separating the principal ray from the optical axis in the mirror optical system.

FIG. 61 is an explanatory diagram of a second method for preventing the vignetting by separating the principal ray from the optical axis in the mirror optical system.

FIG. 62 is a schematic diagram of a zoom optical system using a conventional reflection mirror.

FIG. 63 is a schematic view of an observation optical system having a prism reflecting surface with a curvature.

FIG. 64 is a schematic view of an observation optical system having a curvature on another prism reflecting surface.

[Explanation of symbols]

Ri, R _{m, n} Surface Bi i-th optical element Di Surface spacing along the reference axis Ndi Refractive index νdi Abbe number A _{i, j} Reference axis B _L = R1 Aperture P Final image plane Ni Intermediate image formation

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kenichi Kimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Norihiro Namba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Incorporated (72) Inventor Hiroshi Saruwatari 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kenji Akiyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (15)

[Claims] 1. A two-refractive surface and a plurality of reflecting surfaces are formed on the surface of a transparent body, and a light beam enters the inside of the transparent body from one refracting surface, and is repeatedly reflected by the plurality of reflecting surfaces to separate. A plurality of reflecting surfaces composed of an optical element or / and a surface reflecting mirror configured to be emitted from the refracting surface of the above, and an incident light beam is repeatedly reflected and emitted by the plurality of reflecting surfaces. A plurality of optical elements that are formed, and form an image of an object through the plurality of optical elements,
A reflective zoom optical system, wherein zooming is performed by changing the relative positions of at least two optical elements of the plurality of optical elements. 2. The reflective zoom optical system according to claim 1, wherein at least two optical elements for changing the relative position have a reference axis for incidence and a reference axis for emission respectively parallel to each other. 3. The reflective zoom optical system according to claim 2, wherein the at least two optical elements that change the relative position move in parallel with each other on one moving plane. 4. The reflection according to claim 2, wherein at least two optical elements for changing the relative position are such that the reference axis of incidence and the reference axis of emission are in the same direction. Type zoom optics. 5. One of at least two optical elements for changing the relative position has an incident reference axis and an outgoing reference axis oriented in the same direction, and the other optical element has an incident reference axis. The reflection type zoom optical system according to claim 2 or 3, wherein the directions of the reference axes which are emitted are in the opposite directions. 6. The reflection according to claim 2, wherein at least two optical elements for changing the relative position are such that the reference axis of incidence and the reference axis of emission are opposite to each other. Type zoom optics. 7. The reflection type zoom according to claim 1, wherein one of at least two optical elements that change the relative position is moved to perform focusing. Optical system. 8. The reflective zoom optical system according to claim 1, wherein an optical element other than at least two optical elements that change the relative position is moved to perform focusing. system. 9. The reflection type zoom optical system according to claim 1, wherein an intermediate object image is formed at least once in the optical path of the reflection type zoom optical system. Zoom optics. 10. The reflection type according to claim 1, wherein among the plurality of reflecting surfaces, all of the curved reflecting surfaces have a shape having only one symmetrical surface. Zoom optics. 11. The reflective zoom according to claim 1, wherein the reference axes of at least two optical elements that change the relative position are all on one plane. Optical system. 12. The reflective zoom optical system according to claim 11, wherein at least a part of a reference axis of an optical element other than at least two optical elements that change the relative position is on the plane. 13. At least one optical element of the plurality of optical elements is such that at least two optical elements that change a relative position of a normal line of the reflecting surface at an intersection of a reference axis and the reflecting surface move. The reflecting surface is inclined with respect to the moving plane.
The reflective zoom optical system according to any one of 1. 14. The reflective zoom optical system according to claim 1, wherein the at least two optical elements that change the relative position move on two moving planes that are inclined with respect to each other. 15. An image pickup apparatus comprising the reflective zoom optical system according to claim 1, wherein the image of the object is formed on an image pickup surface of an image pickup medium. .