JP2000321500A - Image formation optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image formation optical system which is composed of a small-sized, high-performance prism optical system. SOLUTION: This image formation optical system has a prism member 10 which is formed of a medium whose refractive index is larger than 1 and the prism member 10 has a 1st transmission surface 14, 1st to 3rd reflection surfaces 11 to 13, and a 2nd transmission surface 15. The 2nd reflection surface 12 and 3rd reflection surface 13 are so arranged that the track of the on-axis main light beam in the prism is folded triangularly and an on-axis main light beam made incident on the 2nd reflecting surface 12 and the on-axis main light beam projected from the 3rd reflection surface 13 form crossing optical paths. At least one reflection surface among the 1st to 3rd reflection surfaces 11 to 13 has a curved surface shape giving power to luminous flux and the curved surface shape is a rotationally asymmetrical surface shape which corrects aberrations generated by eccentricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging optical system constituted by an eccentrically arranged reflecting surface having a power. For example, the present invention relates to an imaging optical system or a finder optical system used for a camera or a video camera. It relates to an imaging optical system to be used.

[0002]

2. Description of the Related Art In recent years, there has been proposed an optical system which is reduced in size by giving power to a reflecting surface and folding an optical path in an optical axis direction. The configuration using such a reflection surface mainly includes a prism and a mirror. Although these are both optical systems using a reflecting surface, their characteristics are greatly different.

When a curvature (radius of curvature r) is given to these reflecting surfaces, the power of the surfaces is filled with a medium having a refractive index n larger than 1 according to a paraxial power calculation formula. For a given prism, the power becomes -2n / r, and for a mirror, it becomes -2 / r, and the power differs even with the same curvature. Therefore, since the prism can have the same power with a curvature of 1 / n compared to the mirror, the prism can reduce the amount of aberration generated on the reflection surface and is more advantageous in performance. Also, since the prism is a single member, it has two refraction surfaces, an incident refraction surface and an exit refraction surface, in addition to the reflection surface.
This is advantageous for aberration correction as compared with a mirror having only one reflecting surface with one member. In addition, since the prism is filled with a medium having a refractive index larger than 1, the optical path length can be increased as compared with a mirror arranged in the air, and a reflective surface can be secured even if the focal length is short. Was relatively easy. On the other hand, in general, a reflective surface is required to have high assembly accuracy because performance is greatly degraded due to an eccentricity error as compared with a refractive surface. The prism that can fix the relative position by integrating the above is advantageous because it can prevent the performance degradation due to the assembly. As described above, the prism has many advantages over the mirror.

[0004] On the other hand, if a surface having power is arranged to be inclined with respect to the optical axis, the generated aberration becomes rotationally asymmetric. For example, when rotationally asymmetric distortion occurs, a square object may become trapezoidal. Such rotationally asymmetric aberrations (hereinafter, referred to as eccentric aberrations) could not be corrected in principle on a rotationally symmetric surface. Therefore, a rotationally asymmetric curved surface such as an anamorphic surface is sometimes used.

[0005] Such a prism optical system is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-313829. JP-A-8-31
No. 3829 is an eyepiece optical system comprising a prism having two reflection times and a first transmission surface counting from the pupil side and having the same surface as the second reflection surface. Each of the reflection surfaces was a rotationally asymmetric anamorphic surface.

[0006] Among them, a prism optical system having three times of reflection is disclosed in JP-A-9-33855, JP-A-9-73043, and JP-A-9-197336. In addition, a spherical surface or an anamorphic surface is used as the reflection surface.

Japanese Unexamined Patent Publication No. 9-33855 discloses an eyepiece optical system having an optical path whose optical axis makes one rotation inside a prism. The third reflecting surface and the first reflecting surface counted from the pupil side
The transmission surface, the second reflection surface, and the second transmission surface were formed on the same surface, and the other transmission surface, the reflection surface formed separately from the reflection surface, was only one of the second reflection surfaces. . The exit direction of the prism optical system was oblique at about 45 ° with respect to the incident direction.

Japanese Patent Application Laid-Open No. Hei 9-73043 discloses an eyepiece optical system whose optical axis takes an optical path like the letter M in the alphabet. Further, for example, in the fifth embodiment, the second reflection surface and the second transmission surface are formed on the same surface counted from the pupil side, and the other transmission surface and the reflection surface formed separately from the reflection surface are: , A first reflecting surface and a third reflecting surface. Further, the exit direction of the prism optical system of this embodiment was opposite to the incident direction. In addition, Japanese Patent Application Laid-Open No.
In No. 7336, the second reflecting surface is counted from the pupil side, and is formed of the same surface as the first transmitting surface and the second transmitting surface.

[0009]

However, these prior arts have various problems as described below.

In Japanese Unexamined Patent Publication No. Hei 8-313829, power is applied to the reflecting surface of the prism. However, since there are only two reflecting surfaces, there is a limit in performance, so that the aperture becomes large or the angle of view becomes large. In some cases, performance could not be met.

Therefore, it is considered that an increase in the number of reflections makes it possible to correct aberrations more advantageously. However, the prior example of the three-time reflecting prism, in which the number of reflections is one more than the above-described prior example, did not necessarily achieve both miniaturization and high performance at the same time.

In Japanese Patent Application Laid-Open No. 9-33855, the optical path is such that it rotates inside the prism, so that the prism can be effectively reduced in size by folding the optical path. However, due to its configuration, when the light flux is large, it is difficult to form the two transmitting surfaces and the three reflecting surfaces as independent surfaces, respectively. The first transmitting surface is the third reflecting surface, and the second transmitting surface is the first transmitting surface. It had to be configured on the same plane as the transmitting surface. Therefore, when the light is reflected by the first reflection surface and the third reflection surface, the angle must be equal to or larger than the total reflection angle, and sufficient aberration correction cannot be performed. In addition, since two of the three reflecting surfaces have limitations on the reflection angle, there is little freedom in the emitting direction with respect to the incident direction, and in some cases the size cannot be reduced in consideration of the arrangement of other members.

JP-A-9-73043, JP-A-9-19
In No. 7336, since the light path is like the letter M in the alphabet, the second reflection surface easily overlaps with the effective portion of the light flux on both or any one of the first transmission surface and the second transmission surface. I had to configure it. Therefore, similarly to the above, the reflection angle of the second reflection surface must be equal to or larger than the total reflection angle, and sufficient aberration correction cannot be performed. In addition, since the exit direction becomes an angle nearly parallel to the incident direction, the back focus increases,
When another optical system is connected in addition to the prism optical system, the size in the incident direction becomes large, so that downsizing may not be achieved in some cases.

As described above, any of the prior arts has a problem in performance or size, and a compact and high-performance prism optical system satisfying both of them has not been achieved.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an imaging optical system including a small and high-performance prism optical system.

[0016]

According to the present invention, there is provided an image forming optical system having a positive refractive power as a whole for forming an object image. A prism member formed of a medium having a refractive index (n) greater than 1 (n> 1), wherein the prism member is
Joined or integrally formed having a first transmitting surface for entering a light beam into the prism, first to third reflecting surfaces for reflecting the light beam inside the prism, and a second transmitting surface for emitting the light beam outside the prism. When the axial principal ray is projected onto a plane defined by the axial principal ray incident on the second reflecting surface and the axial principal ray reflected from the second reflecting surface. The second reflection surface and the third reflection surface fold the orbit of the axial principal ray in the prism into a triangular shape, and the axial principal ray incident on the second reflection surface and the third reflection surface The first and third reflecting surfaces are arranged so as to form an intersecting optical path with the emitted axial chief ray, and at least one of the first to third reflecting surfaces has a curved shape that gives power to a light beam; Rotationally asymmetric shape corrects aberrations caused by eccentricity And it is characterized in that it is configured to have a shape.

In this case, the intersecting optical path formed by the second reflecting surface and the third reflecting surface forms an axial principal ray incident on the third reflecting surface and an axial principal ray reflected from the third reflecting surface. Plane intersection defined by a plane defined by the on-axis principal ray incident on the second reflecting surface and the on-axis principal ray reflected from the second reflecting surface, or on the third reflecting surface. The plane defined by the incident axial principal ray and the axial principal ray reflected from the third reflecting surface is the plane principal ray incident on the second reflecting surface and the axial principal ray reflected from the second reflecting surface. It is desirable to be configured so as to be any of three-dimensional intersections that three-dimensionally intersect within a range of ± 20 ° with respect to a plane defined by light rays.

Note that, regarding the surface arrangement order, in order from the object side, a first transmission surface, a first reflection surface, a second reflection surface, and a third
An optical path is formed in the order of the reflection surface and the second transmission surface, or the first transmission surface, the second reflection surface, the third reflection surface, the first reflection surface, and the second transmission surface are formed. The optical paths can be formed in order.

Hereinafter, the reason and operation of such a configuration in the present invention will be described.

A refractive optical element such as a lens can be given power only by giving a curvature to its boundary surface. Therefore, when a light beam is refracted at the boundary surface of the lens, chromatic aberration due to the chromatic dispersion characteristics of the refractive optical element is inevitably generated. As a result, another refractive optical element is generally added for the purpose of correcting chromatic aberration.

On the other hand, a reflecting optical element such as a mirror or a prism does not generate chromatic aberration even if the reflecting surface has power, and another optical element is used only for the purpose of correcting chromatic aberration. No need to add. Therefore, in the optical system using the reflective optical element, the number of constituent optical elements can be reduced from the viewpoint of chromatic aberration correction, as compared with the optical system using the refractive optical element.

At the same time, since the reflection optical system using the reflection optical element folds the optical path, the size of the optical system itself can be reduced as compared with the refractive optical system.

Further, since the reflecting surface has a higher sensitivity to eccentricity error than the refracting surface, high accuracy is required for assembly adjustment.
However, among the reflective optical elements, since the relative positional relationship between the surfaces of the prisms is fixed, the eccentricity may be controlled as a single prism, and unnecessary assembly accuracy and adjustment man-hours are unnecessary.

Further, the prism has a refracting surface, an entrance surface, an exit surface, and a reflective surface, and has a greater degree of freedom for aberration correction than a mirror having only a reflective surface. In particular, by allowing the reflection surface to share most of the desired power and reducing the power of the entrance surface and the exit surface, which are refraction surfaces, the degree of freedom in correcting aberrations is larger than that of a mirror, while maintaining the degree of freedom for aberrations. Compared with such a refractive optical element, the occurrence of chromatic aberration can be extremely reduced. Further, since the inside of the prism is filled with a transparent body having a higher refractive index than air, the optical path length can be made longer than that of air. Thinning and miniaturization are possible.

According to the present invention, there is provided an imaging optical system having an overall positive refractive power for forming an object image without forming an intermediate image, for which the refractive index (n) is larger than 1. (N> 1) a prism member formed of a medium, the prism member having a first transmitting surface through which a light beam enters the prism, a first to a third reflecting surface reflecting the light beam within the prism, It is constituted by one bonded or integrally formed prism having a second transmission surface for emitting a light beam outside the prism.

By the way, as described in the section of the prior art, when the reflecting surface is inclined with respect to the optical axis, rotationally asymmetric eccentric aberration occurs. Therefore, it is desirable that at least one reflecting surface among the surfaces used in the present invention is a rotationally asymmetric surface. With such a configuration, it is possible to correct rotationally asymmetric eccentric aberration.

Here, the definition of the eccentric system will be described.

First, the coordinate system used and the rotationally asymmetric surface will be described.

When a ray passing through the center of the object point and passing through the center of the stop and reaching the center of the image plane is defined as an axial principal ray, an optical axis defined by a straight line that intersects the first surface of the optical system is defined as Z axis, orthogonal to the Z axis, and define the axis in the eccentric plane of each surface constituting the prism optical system as the Y axis, the axis orthogonal to the optical axis and orthogonal to the Y axis Let it be the X axis. The ray tracing direction will be described with reference to the normal ray tracing from the object to the image plane.

The rotationally asymmetric surface used in the present invention is preferably a plane-symmetric free-form surface having only one plane of symmetry.

Here, the free-form surface used in the present invention is:
It is defined by the following equation (a). Note that the Z axis of the definition formula is the axis of the free-form surface.

[0032] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term, c: curvature of the vertex k: conic constant (conical constant) r = √ (X ² + Y ² ).

The free-form surface term is Here, C _j (j is an integer of 2 or more) is a coefficient.

The free-form surface generally includes an XZ plane,
Although neither YZ plane has a symmetry plane, in the present invention, X
By setting all the odd-order terms of 0 to 0, the YZ plane and the flat
The free-form surface has only one line of symmetry plane. example
For example, in the above definition formula (a), C_Two, C_Five, C₇,
C₉, C₁₂, C₁₄, C₁₆, C₁₈, C₂₀, C_{twenty three}, C_{twenty five}, C
₂₇, C₂₉, C₃₁, C₃₃, C₃₅Set the coefficient of each term of ... to 0
It is possible by doing.

By setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane exists. For example, in the above definition formula, C ₃ ,
_{C 5, C 8, C 10} , C 12, C 14, C 17, C 19, C 21, C
₂₃ , C ₂₅ , C ₂₇ , C ₃₀ , C ₃₂ , C ₃₄ , C ₃₆ ...

One of the directions of the symmetry plane is a symmetry plane, and the eccentricity in the corresponding direction, for example, the eccentric direction of the optical system with respect to the symmetry plane parallel to the YZ plane is in the Y-axis direction. By making the eccentric direction of the optical system the X-axis direction with respect to the symmetric plane parallel to the XZ plane, it is possible to effectively correct rotationally asymmetric aberrations caused by the eccentricity while improving the productivity. Becomes possible.

Further, the above-mentioned definition formula (a) is shown as one example as described above, and the present invention uses a rotationally asymmetric surface having only one symmetrical surface to obtain a rotation generated by eccentricity. It is characterized by correcting asymmetric aberrations and at the same time improving productivity, and it goes without saying that the same effect can be obtained for any other definitional expressions.

The use of such a rotationally asymmetric surface makes it possible to correct eccentric aberration. However, no matter how much the rotationally asymmetric surface is used, the performance is limited if the aberration correction surface is small. Therefore, it is advantageous in terms of performance to configure the prism optical system with a large number of reflecting surfaces.

However, simply increasing the number of reflecting surfaces of the prism does not necessarily provide an advantage in performance. Since the prism generally needs to bend the light beam so that the effective portions of the reflecting surface do not overlap each other, for example, when there are the a-th surface, the b-th surface, and the c-th surface in the order of the rays, It is necessary to increase the reflection angle of the b-th surface so that the portions do not overlap, or to increase the distance between the a-th surface and the b-th surface and the b-th surface to the c-th surface. In general, the amount of eccentric aberration increases as the reflection angle increases, and thus the performance increases if the reflection angle is increased. In addition, if the interval between the reflection surfaces is increased, the optical path length must be increased, so that the load on the performance increases, and the size of the prism also increases.

First, an optical path is defined.
When an optical path is bent by a plurality of reflecting surfaces, its optical axis is not always on the same two-dimensional plane, and may take a three-dimensional optical path that is not on the same plane. The imaging optical system of the present invention may take a three-dimensional optical path. In the following description, an optical path is defined based on a two-dimensional standard that includes a three-dimensional optical path.

The optical axis of the decentered optical system is a light beam that passes through the center of the object point, passes through the center of the stop, and reaches the center of the image plane, and is referred to as an axial principal ray. Therefore, the optical path is defined by a projected axial principal ray that projects the axial principal ray onto a plane defined by the axial principal ray incident on the second reflecting surface and the axial principal ray reflected from the second reflecting surface. I do. Even if a three-dimensional optical path is taken by this definition, it is included in the scope of the present invention.

By the way, if the number of reflections of the prism is increased, the performance becomes advantageous, but the size is disadvantageous. As described above, since the number of reflections is related to both performance and size, the number of reflections that can achieve both effects in a well-balanced manner is set. Here, if the number of reflections of the image forming optical system is set to two or less, there is a limit in correction of eccentric aberration as described in the related art, which is disadvantageous in performance. If the number is four or more, the degree of freedom in the bending direction is reduced, and it becomes difficult to reduce the size of the imaging optical system. In addition, when the number of reflections is increased, the prism cannot be formed unless the common reflection surface is used, so that the performance is not always advantageous. In addition, the influence of the performance degradation on the manufacturing error increases, which is not preferable. Therefore, the number of reflections is set to three in the imaging optical system of the present invention.

That is, the prism member constituting the image forming optical system of the present invention includes a first transmitting surface through which a light beam enters the prism, a first to a third reflecting surface through which the light beam is reflected within the prism, and a light beam through the prism. It is composed of one prism that is joined or integrally formed and has a second transmission surface that exits outside the prism.

Then, the second reflecting surface and the third reflecting surface are folded into a triangular shape of the trajectory of the axial principal ray in the prism, and emitted from the axial principal ray entering the second reflecting surface and the third reflecting surface. And an on-axis chief ray.

When the number of reflections is set to three, if the optical path is simply folded at each reflecting surface, the horizontal or vertical dimension of the prism optical system becomes large, and the entire optical system becomes large. It is difficult to reduce the size and performance of the device. In addition, since the optical path length becomes long, it is not suitable for a wide-angle optical system.

The size of the entire optical system can be reduced by folding the optical path in the thickness direction. However, enlargement in the lateral direction is inevitable. In order to avoid this, and to avoid the increase in the lateral direction while maintaining the thinness, in the present invention, the three surfaces of the prism are reflected so that a part of the optical path inside the prism becomes triangular to form an intersecting optical path. Among the surfaces, the optical paths of the continuous two reflecting surfaces, the second reflecting surface and the third reflecting surface, are configured to intersect inside the prism.

As described above, when the optical path formed by two continuous reflecting surfaces is configured to intersect inside the prism, it is possible to avoid the enlargement in the lateral direction while keeping the prism thin, and furthermore, the two reflections Since the amount of eccentricity of the surface can be reduced, the occurrence of eccentric aberration can be reduced. Further, by distributing the positive power to the two surfaces and sharing the same, the amount of eccentric aberration can be further reduced.

Further, the first reflecting surface other than the two reflecting surfaces can have a degree of freedom in the direction in which the image plane is arranged or in the incident direction of the light beam from the object. Therefore, it is possible to select an optimal shape and arrangement according to the purpose of the imaging optical system.

In the present invention, at least one of the three reflecting surfaces has a curved shape for giving power to a light beam, and the curved shape is rotationally asymmetric for correcting aberrations caused by eccentricity. It is configured to have a planar shape. With this configuration, it is possible to apply a positive power for the imaging optical system to the prism member, and to correct the rotationally asymmetric eccentric aberration as described above.

In the image forming optical system according to the present invention, the second
The intersection optical path formed by the reflecting surface and the third reflecting surface is:
A plane defined by the axial principal ray incident on the third reflecting surface and the axial principal ray reflected from the third reflecting surface is reflected by the axial principal ray incident on the second reflecting surface and the second reflecting surface. Or a plane defined by an axial principal ray incident on the third reflecting surface and an axial principal ray reflected from the third reflecting surface. But the second
Any one of a three-dimensional intersection that three-dimensionally intersects within a range of ± 20 ° with respect to a plane defined by the axial principal ray incident on the reflecting surface and the axial principal ray reflected from the second reflecting surface It is desirable to be constituted as follows.

The crossing optical paths formed by the second and third reflecting surfaces intersect on a plane to correct eccentric aberration correction.
Although desirable from the viewpoint of manufacturability, the axial chief ray is
The plane of incidence incident on the reflecting surface (the plane defined by the axial principal ray incident on the third reflecting surface and the axial principal ray reflected from the third reflecting surface) is such that the axial principal ray is transmitted to the second reflecting surface. Three-dimensionally intersects an incident surface (a plane defined by an axial principal ray incident on the second reflecting surface and an axial principal ray reflected from the second reflecting surface) within ± 20 °. In the case of a three-dimensional intersection, it is desirable to obtain a degree of freedom in shape arrangement according to the purpose of the imaging optical system. However, if the angle exceeds ± 20 °, it is necessary to correct aberrations simultaneously and independently at all positions on the image plane, which makes it extremely difficult to correct aberrations in practice.

In the image forming optical system according to the present invention, the order of surface arrangement is such that the first transmission surface and the first transmission surface are arranged in order from the object side.
An optical path may be formed in the order of the reflection surface, the second reflection surface, the third reflection surface, and the second transmission surface, or the first transmission surface, the second reflection surface, and the third reflection surface , A first reflecting surface, and a second
An optical path can be formed in the order of the transmitting surfaces.

FIG. 28 shows an image forming optical system according to the present invention.
The possible arrangements of the first reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, and the image plane 3 are classified. FIG.
In the cases (a) and (b), the luminous flux from the object forms an optical path in the order of the first reflection surface 11, the second reflection surface 12, and the third reflection surface 13, and the image of the object is formed on the image surface 3. Form an image. FIG.
In the cases (c) and (d), the luminous flux from the object forms an optical path in the order of the second reflecting surface 12, the third reflecting surface 13, and the first reflecting surface 11, and an image of the object is formed on the image surface 3. Form an image. And FIG.
In the case of 8 (a), the second reflection surface 12 is arranged such that the light beam reflected by the second reflection surface 12 is directed toward the object side,
The image plane 3 is formed on the opposite side to the object side with the prism member interposed therebetween. In the case of FIG. 28 (b), the light beam reflected by the second reflection surface 12 is opposite to the object side. The second reflecting surface 12 is arranged so as to face the side, and the image plane 3 is formed on the object side of the prism member. In the case of FIG. The first reflecting surface 11 is arranged so that the light beam reflected by the object faces in the direction opposite to the object side, and the image surface 3 is formed on the opposite side to the object side with the prism member interposed therebetween. FIG. 28
In the case of (d), the first reflection surface 11 is arranged so that the light beam reflected by the first reflection surface 11 is directed to the object side, and the image plane 3 is formed on the object side of the prism member. It is configured.

In the case of FIGS. 28 (a) and (c),
The rotation direction of the light beam along the triangular optical path formed by the second reflection surface 12 and the third reflection surface 13 and the first reflection surface 1
28 is the same as the direction of rotation of the light beam along the optical path that is incident and reflected (counterclockwise in the case of FIG.
In the case of FIGS. 28B and 28D, the second reflecting surface 12 is rotated clockwise.
The rotation direction of the light beam along the triangular light path formed by the first reflection surface 11 and the rotation direction of the light beam along the light path incident on and reflected by the first reflection surface 11 are opposite to each other. It is configured.

Further, in the present invention, the first reflecting surface and the second transmitting surface of the prism member may be formed on the same surface. In this case, by forming the first reflection surface as a total reflection surface, the same surface can be configured as a surface that is used for both reflection and transmission.

In the present invention, two of the three reflecting surfaces, specifically, the second reflecting surface and the third reflecting surface, or the first reflecting surface and the second reflecting surface, or the first reflecting surface. Both the reflecting surface and the third reflecting surface may be configured to have a rotationally asymmetric surface shape that applies power to the light beam and corrects aberration generated by eccentricity. Of course, all three reflecting surfaces may be configured to have a rotationally asymmetric surface shape that applies power to the light beam and corrects aberrations caused by eccentricity.

Further, the first transmission surface, the second transmission surface, or both transmission surfaces may be configured to have a rotationally asymmetric surface shape for applying power to a light beam and correcting aberrations caused by eccentricity. . It is effective to take such a surface shape on the refraction surface in order to correct aberrations caused by eccentricity.

In the present invention, the second transmission surface may be formed by a plane. Further, the first transmission surface may be formed by a plane.

As described above, if an appropriate optical path is set using three reflecting surfaces, miniaturization and high performance can be achieved.
Depending on the arrangement of the openings in the optical system, sufficient performance may not be obtained.

In a general refractive optical system or the like, it was easy to arrange an aperture such as a brightness stop between lenses. However, in the prism optical system, since the inside of the prism is filled with a medium, the prism is divided so that a brightness stop can be arranged in order to arrange the opening in the middle part of the optical path, or the opening is formed in the prism. It was necessary to make grooves to decide. Also in the present invention, it is possible to configure by dividing the prism, but when the prism is divided,
Performance degradation due to assembly errors is likely to occur, which is not preferable in terms of performance. Further, even if an opening is determined by forming a groove in the prism, it is not preferable in terms of performance because it is actually affected by diffuse reflection and scattered light. Further, when the opening is determined by the groove, the opening cannot be physically narrowed, so that another member such as an ND filter is required, which increases the cost. Therefore, arranging the opening in the middle portion of the optical path causes various problems and is not preferable.

On the other hand, if the opening is arranged outside the prism,
Since it is not necessary to divide the prism or form a groove, the above-described performance problem can be solved. Therefore, it is desirable that the three reflecting surfaces of the prism be arranged between the opening of the optical system and the object plane or between the opening and the image plane. It is desirable to arrange the aperture so that the entrance pupil is formed.

The rotationally asymmetric surface shape used for the reflection surface and the transmission surface of the present invention is desirably a plane-symmetric free-form surface shape having only one symmetrical surface.

As described above, by adopting the configuration of the present invention, it is possible to obtain a prism optical system that is small, thin, and high-performance as compared with the conventional configuration.

Next, among the reflecting surfaces, conditions relating to the second reflecting surface and the third reflecting surface forming an intersecting optical path will be described.
In order to effectively reduce the size of the prism by intersecting and folding the optical axis, it is necessary to appropriately set the reflection angle of the reflection surface at the intersection. Therefore, it is desirable that the second reflecting surface and the third reflecting surface at the intersection satisfy at least one of the following conditional expressions (1) and (2).

5 ° <θ ₁ <50 ° (1) 5 ° <θ ₂ <50 ° (2) where θ ₁ is the angle of incidence of the axial principal ray on the second reflecting surface, θ
₂ is the angle of incidence of the axial principal ray on the third reflecting surface.

When the upper limit of 50 ° to these conditional expressions is exceeded, the reflection angle becomes large and the optical axis cannot be folded effectively, so that even if the optical axes intersect, the effect of compactness is reduced, and If the lower limit of 5 ° is exceeded, the reflection angle becomes too small and overlaps with other effective portions of the reflection surface, so that the prism member of the present invention cannot be formed.

It is more preferable that at least one of 15 ° <θ ₁ <35 ° (1-1) 15 ° <θ ₂ <35 ° (2-1) is satisfied.

It is preferable that both the second reflecting surface and the third reflecting surface satisfy the following conditional expression.

5 ° <θ ₁ <50 ° (1) 5 ° <θ ₂ <50 ° (2) Similarly to the above description, when the upper limit of these conditional expressions is exceeded by 50 °. If the size is less than the lower limit of 5 °, the configuration of the prism becomes difficult.

It is more preferable to satisfy both the following conditions: 10 ° <θ ₁ <45 ° (1-2) 10 ° <θ ₂ <45 ° (2-2)

It is desirable that the first reflecting surface satisfies the following conditional expression (3).

30 ° <θ ₃ <60 ° (3) where θ ₃ is the angle of incidence of the axial principal ray on the first reflecting surface.

If the lower limit of 30 ° to the above-mentioned conditional expression is exceeded, it becomes impossible to maintain the spatial distance between the transmitting surface disposed before and after the first reflecting surface and the other surface, and the first reflecting surface Cannot be configured as independent surfaces. Also, if the upper limit of 60 ° is exceeded,
The angle of incidence on the first reflecting surface becomes too large, and the eccentric aberration generated on the first reflecting surface becomes too large, making it impossible to correct on other surfaces. In addition, although it is possible to reduce the occurrence of decentering aberration by weakening the power of the first reflecting surface, the power burden on the other second reflecting surface and the third reflecting surface is increased, and the second reflecting surface and the third reflecting surface are hardened. The eccentric aberration generated on the three reflecting surfaces is now too large, and the aberration is deteriorated, so that good results cannot be obtained.

More preferably, when the angle of view becomes wider, it is preferable to satisfy the following condition: 30 ° <θ ₃ <51 ° (3-1) The meaning of the upper and lower limits is
This is the same as the condition (3).

More preferably, it is preferable to satisfy the following condition: 30 ° <θ ₃ <47 ° (3-2) The meaning of the upper and lower limits is
This is the same as the condition (3).

When the axial principal ray is projected onto a plane defined by the axial principal ray incident on the second reflecting surface and the axial principal ray reflected from the second reflecting surface, the second reflecting surface When the angle formed between the axial principal ray incident on the optical axis and the axial principal ray emitted from the third reflecting surface is θ ₄ , it is desirable that the following conditional expression be satisfied.

70 ° <θ ₄ <95 ° (4) This condition is also a condition relating to the arrangement of the surfaces. If the lower limit of 70 ° of the above conditional expression is exceeded, the spatial distance between the second reflecting surface and the third reflecting surface becomes too short, and it becomes impossible to arrange the second reflecting surface and the third reflecting surface. Also, the upper limit of 95 °
When the distance exceeds, the spatial distance between the second reflection surface and the third reflection surface is increased, but the distance between the surfaces including other transmission surfaces is reduced, and other surfaces cannot be arranged.

Here, the power of the decentered optical system and the power of the optical surface will be defined. As shown in FIG. 29, when the eccentric direction of the eccentric optical system S is set in the Y-axis direction, a light beam having a minute height d in a YZ plane parallel to the axial principal ray of the eccentric optical system S is extracted. An angle formed when the light ray incident from the object side and emitted from the decentered optical system S and projected on the YZ plane of the axial principal ray is δy, and δy / d is the power Py of the decentered optical system S in the Y direction. A light beam having a minute height d in the X direction parallel to the axial principal ray of the decentered optical system and orthogonal to the YZ plane is incident from the object side, and emitted from the decentered optical system S and the axial principal ray. Δx, and δx / d is the power Px of the eccentric optical system S in the X direction, when the projection is made on a plane orthogonal to the YZ plane and including the axial principal ray. Similarly, the power Pny in the Y direction and the power Pn in the X direction of the decentered optical surface n forming the decentered optical system S
x is defined.

Further, the reciprocals of these powers are respectively the focal length Fy of the eccentric optical system in the Y direction, the focal length Fx of the eccentric optical system in the X direction, and the focal length F of the eccentric optical surface n in the Y direction.
ny, defined as the focal length Fnx in the X direction.

By the way, in the portion where the optical axes intersect, the two reflection surfaces involved in the intersection to some extent and the optical surfaces disposed before and after the two intersects in order to fill both the light beam at the time of incidence and the light beam at the time of emission with the medium. Must be set appropriately. Therefore, if the configuration is such that the light beam diverges, the light beam is vignetted and cannot sufficiently pass through the light beam, and the angle of view cannot be increased, so that the prism optical system can be made compact. Can not. Therefore, it is desirable that at least one of the second reflecting surface and the third reflecting surface has a positive power to converge the light beam.

At this time, the powers of the second reflecting surface and the third reflecting surface forming the cross optical path in the X and Y directions are respectively represented by Ps
x and Psy, and the powers of the entire prism in the X and Y directions are Px and Py, respectively, the second reflecting surface and the third
It is desirable that at least one of the reflecting surfaces satisfies the following conditional expression.

0.001 <Psx / Px <100 (5) When the value exceeds the upper limit of 100 of the conditional expression, the power of the surface becomes too strong, and excessive aberration occurs in the X direction, so that correction cannot be performed. Therefore, it is difficult to ensure high performance. If the lower limit of 0.001 is exceeded, the power of the surface becomes too weak, so that the convergence effect of the light beam is reduced and X
The compactness of the direction is impaired.

It is more preferable to satisfy 0.01 <Psx / Px <1 (5-1).

More preferably, it is desirable to satisfy 0.4 <Psx / Px <0.65 (5-2).

At this time, it is desirable to satisfy the following conditional expression.

0.001 <Psy / Py <100 (6) When the value exceeds the upper limit of 100 of the conditional expression, the power of the surface becomes too strong, and excessive aberration occurs in the Y direction, so that correction cannot be completed. Therefore, it is difficult to ensure high performance. If the lower limit of 0.001 is exceeded, the power of the surface becomes too weak, so that the convergence effect of the light beam is reduced and Y
The compactness of the direction is impaired.

It is more preferable to satisfy 0.01 <Psy / Py <1 (6-1).

More preferably, it is desirable to satisfy the following condition: 0.3 <Psy / Py <0.7 (6-2)

It is more preferable that the second reflecting surface and the third reflecting surface
It is preferable that both surfaces have a positive power. With such a configuration, since the light beam is further converged, the prism can be configured to be compact.

At this time, the powers of the second reflecting surface and the third reflecting surface in the X and Y directions are P2x, P3x, and P3x, respectively.
Assuming that P2y and P3y and the powers of the entire prism in the X and Y directions are Px and Py, respectively, it is desirable to satisfy the following conditional expressions.

0.001 <P2x / Px <100 (7) 0.001 <P3x / Px <100 (8) If the upper limit of 100 of these conditional expressions is exceeded, the power of the surface becomes strong. It becomes too much, and excessive aberrations occur in the X direction, making it difficult to ensure high performance. If the lower limit of 0.001 is exceeded, the power of the surface becomes too weak, so that the light beam converges. And the compactness in the X direction is impaired.

More preferably, it is desirable to satisfy 0.01 <P2x / Px <1 (7-1) 0.01 <P3x / Px <1 (8-1)

At this time, it is desirable to satisfy the following conditional expression.

0.001 <P2y / Py <100 (9) 0.001 <P3y / Py <100 (10) When the value exceeds the upper limit of 100 of these conditional expressions, the surface power becomes strong. It is difficult to ensure high performance because of excessive aberrations in the Y direction, and when the value exceeds the lower limit of 0.001, the power of the surface becomes too weak, so that the light beam converges. And the compactness in the Y direction is impaired.

It is more preferable to satisfy the following condition: 0.01 <P2y / Py <1 (9-1) 0.01 <P3y / Py <1 (10-1)

The reflecting surface other than the total reflecting surface of the prism of the present invention may be constituted by a reflecting surface having a thin metal film such as aluminum or silver formed on the surface or a reflecting surface having a dielectric multilayer film formed thereon. Is preferred. When the metal thin film has a reflecting action, it is possible to easily obtain a high reflectance. In the case of a dielectric reflection film, it is advantageous when a reflection film having low wavelength selectivity and low absorption is formed.

Thus, it is possible to obtain a low-cost and compact imaging optical system in which the manufacturing accuracy of the prism is eased.

In the image forming optical system according to the present invention, it is needless to say that focusing of the image forming optical system can be performed by extending the entire surface or moving the prism. Focusing can be performed by moving the image plane in the direction. Accordingly, even if the direction of incidence of the axial chief ray from the object and the direction of the axial chief ray that emerges from the most image-side surface do not match due to the decentering of the imaging optical system, the axial chief ray due to focusing can be used. It is possible to prevent the shift of the incident side of the principal ray. Further, it is also possible to divide the parallel plane plate into a plurality of wedge-shaped prisms and perform focusing by moving the prism in a direction perpendicular to the Z axis. Also in this case, focusing is possible regardless of the eccentricity of the imaging optical system.

In the present invention, temperature compensation can be achieved by using different materials for the object-side portion and the image-side portion of the prism. In particular, in order to prevent a focus shift due to a temperature change, which is a problem when plastic is used as the material of the prism, it is possible to make the prism portions have powers of different signs.

In the present invention, when two prism portions are joined to each other, it is desirable to provide a relative positioning portion on a surface having no optical action. In particular, when two prism portions having power are joined to a reflection surface as in the present invention, the relative positional accuracy shift causes performance degradation. Therefore, in the present invention,
By providing the relative positioning portion on the surface of the prism having no optical function, it is possible to secure positional accuracy and secure desired performance. In particular, if the two prisms are integrated by a connecting member using the positioning portion, assembly adjustment becomes unnecessary, and the cost can be further reduced.

The optical path may be folded in a direction different from the eccentric direction of the imaging optical system of the present invention by using a reflecting optical member such as a mirror on the object side of the entrance surface of the imaging optical system of the present invention. It is possible. Thereby, the degree of freedom of the layout of the imaging optical system is further increased, and the size of the entire imaging optical device can be reduced.

In the present invention, the image forming optical system can be composed of only a prism. As a result, the number of parts is reduced, and the cost is reduced. Furthermore, it is of course possible to integrate two prisms before and after the stop to form one prism. Thereby, further cost reduction is possible.

In the present invention, in addition to the prism,
Other lenses (positive lens, negative lens) may be included as constituent elements on either the object side or the image side or on both sides.

The image forming optical system of the present invention can be a bright single focus lens. Also, a zoom lens (magnification imaging optical system) can be formed by combining one or a plurality of refractive optical systems on the object side or the image side of the prism.

In the present invention, it is also possible to form the refracting surface and the reflecting surface of the imaging optical system with a spherical surface or a rotationally symmetric aspherical surface.

When the above-described image forming optical system of the present invention is arranged in the image pickup section of the image pickup apparatus, or when the image pickup apparatus has a camera mechanism, the prism member is formed of an optical element having an optical function. The prism member is disposed closest to the object side, the incident surface of the prism member is disposed eccentrically with respect to the optical axis, and a cover member disposed perpendicular to the optical axis is disposed closer to the object side than the prism member. In addition, the prism member is configured so as to have an incident surface that is eccentrically arranged on the object side with respect to the optical axis, and the power arranged coaxially with the optical axis with an air gap interposed between the incident surface and the air surface. The cover lens may be arranged on the object side of the incident surface.

As described above, when the prism member is disposed closest to the object and the eccentric incident surface is provided on the front surface of the photographing apparatus,
Since the incident surface obliquely seen from the subject can be seen, an uncomfortable feeling may be given as if the photographing was performed around a position shifted from the subject. Therefore, by arranging a cover member or a cover lens perpendicular to the optical axis, it is possible to perform imaging without feeling uncomfortable with the object to be imaged, similarly to a general imaging device.

Any of the imaging optical systems of the present invention as described above is arranged as a finder objective optical system, and further, an image erecting optical system for erecting an object image formed by the finder objective optical system. A finder optical system can be configured from the eyepiece optical system.

Further, a camera device can be constructed by including the finder optical system and a photographing objective optical system provided in parallel with the finder optical system.

Further, an imaging optical system comprising any one of the above-described imaging optical systems according to the present invention and an imaging device arranged on an image plane formed by the imaging optical system is provided. Can be.

Further, any one of the imaging optical systems of the present invention as described above is arranged as a photographing objective optical system, and an optical path different from the photographing optical system or an optical path of the photographing objective optical system. The camera device can be provided with a finder optical system disposed in any of the optical paths divided from the camera.

Further, any one of the above-described image forming optical systems of the present invention, an image pickup device arranged on an image plane formed by the image forming optical system, and image information received by the image pickup device. An electronic camera device can be configured to include a recording medium that records the image data, and an image display element that forms an observation image by receiving image information from the recording medium or the image sensor.

An observation system having any one of the above-described imaging optical systems according to the present invention and an image transmission member that transmits an image formed by the imaging optical system along the long axis direction.
An endoscope apparatus can be configured to include an illumination light source and an illumination system having an illumination light transmission member that transmits illumination light from the illumination light source along the long axis direction.

[0115]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 18 of the image forming optical system according to the present invention will be described below. The configuration parameters of each embodiment will be described later.

In Examples 1 to 13 and 15 to 18, as shown in FIG. 1, the center of the stop 2 is set as the origin of the eccentric optical system, and the axial principal ray 1 is moved out of the object center (not shown). It is defined by light rays that pass through the center of the stop 2 and reach the center of the image plane 3. A direction proceeding along the axial principal ray 1 from the center of the object to the first surface (first transmission surface) 14 of the optical system is defined as a Z-axis direction, and a plane including the Z axis and the center of the image plane 3 is defined as a YZ plane. In the direction in which the light beam is bent by the surface of the optical system, and Y
-Take the Y axis in a direction perpendicular to the Z axis in the Z plane. The direction from the object point toward the first surface 14 of the optical system is defined as the positive direction of the Z axis, and the positive direction of the Y axis is defined as the upward direction in the figure. And the Y axis,
The axis constituting the right-handed rectangular coordinate system with the Z axis is defined as the X axis.

In Examples 1 to 13 and 15 to 18, this Y
Each plane is decentered in the −Z plane, and the only symmetric plane of each rotationally asymmetric free-form surface is the YZ plane.

In the fourteenth embodiment, with the center of the stop 2 as the origin of the decentered optical system, the axial principal ray 1 is defined as a ray that exits the center of the object, passes through the center of the stop 2, and reaches the center of the image plane 3. . The direction proceeding along the axial principal ray 1 from the center of the object to the first surface (first transmission surface) 14 of the optical system is defined as the Z-axis direction, and the X-axis and the Y-axis are orthogonal to the Z-axis and mutually orthogonal. Take. The direction from the object point toward the first surface 14 of the optical system is defined as the positive direction of the Z axis.

For the eccentric surface, the amount of eccentricity from the center of the origin of the optical system to the top of the surface (X-axis direction, Y-axis direction, Z-axis direction)
The axial directions are X, Y, and Z, respectively, and the X-axis of the center axis of the surface (for a free-form surface, the Z-axis of the formula (a), and for an aspheric surface, the Z-axis of the formula (b) described later) , Y-axis, and Z-axis tilt angles (α, β, γ (°), respectively)
And is given. In this case, the positive α and β mean counterclockwise with respect to the positive direction of each axis, and the positive γ means clockwise with respect to the positive direction of the Z axis. The rotation of the center axis of the surface by α, β, γ depends on the center axis of the surface and its XYZ.
The orthogonal coordinate system is first rotated counterclockwise by α around the X axis, and then the center axis of the rotated surface is changed to Y in the new coordinate system.
The coordinate system rotated counterclockwise around the axis by β and rotated once is also rotated counterclockwise around the Y axis by β, and then the center axis of the surface rotated twice is added to the new coordinate system. This is to make a γ rotation clockwise around the Z axis of a simple coordinate system.

Further, among the optical working surfaces constituting the optical system of each embodiment, when a specific surface and a subsequent surface constitute a coaxial optical system, a surface interval is given, and in addition, a medium spacing is given. The refractive index and Abbe number are given according to a conventional method.

Further, the shape of the surface of the free-form surface used in the present invention is defined by the above equation (a), and the Z axis of the definition equation is the axis of the free-form surface.

An aspherical surface is a rotationally symmetric aspherical surface given by the following definitional expression.

Z = (y ² / R) / [1+ ｛1− (1 + K) y ² / R ² ｝ ^1/2 ] + Ay ⁴ + By ⁶ + Cy ⁸ + Dy ¹⁰ +... (B) Is the optical axis (on-axis principal ray) where the traveling direction of light is positive, and y is a direction perpendicular to the optical axis. Here, R is a paraxial radius of curvature, K is a conic constant, and A, B, C, D,... Are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.
The Z axis of this definition expression is the axis of the rotationally symmetric aspherical surface.

Note that terms relating to free-form surfaces and aspheric surfaces for which no data is described are zero. Regarding the refractive index,
The values for the d-line (wavelength 587.56 nm) are shown. The unit of the length is mm.

As another definition of the free-form surface, there is a Zernike polynomial given by the following expression (c).
The shape of this surface is defined by the following equation. The Z axis of the defining equation is the axis of the Zernike polynomial. The definition of the rotationally asymmetric surface is defined by polar coordinates of the height of the Z axis with respect to the XY plane, A is the distance from the Z axis in the XY plane, R is the azimuth around the Z axis, and the Z axis It can be expressed by the rotation angle measured from.

X = R × cos (A) y = R × sin (A) Z = D ₂ + D ₃ Rcos (A) + D ₄ Rsin (A) + D ₅ R ² cos (2A) + D ₆ (R ² −1 ^{_{) + D 7 R 2 sin (}} 2A) + D 8 R 3 cos (3A) + D 9 (3R 3 -2R) cos (A) + D 10 (3R 3 -2R) sin (A) + D 11 R 3 sin (3A) + D ^{_{12 R 4 cos (4A) +}} D 13 (4R 4 -3R 2) cos (2A) + D 14 (6R 4 -6R 2 +1) + D 15 (4R 4 -3R 2) sin (2A) + D 16 R 4 sin (4A ^{_{) + D 17 R 5 cos (}} 5A) + D 18 (5R 5 -4R 3) cos (3A) + D 19 (10R 5 -12R 3 + 3R) cos (A) + D 20 (10R 5 -12R 3 + 3R) sin (A) ^{_{+ D 21 (5R 5 -4R 3}} ) sin (3A) + D 22 R 5 sin (5A) + D 23 R 6 cos (6A) + D 24 (6R 6 -5R 4) cos (4A) + D 25 (15R 6 -20R 4 ^{+ 6R 2) cos (2A)} + D 26 (20R 6 -30R 4 + 12R 2 -1) + D 27 (15R 6 -20R 4 + 6R 2) sin (2A) ^{_{D 28 (6R 6 -5R 4)}} sin (4A) + D 29 R 6 sin (6A) ····· ··· (c) In addition, to design an optical system symmetric with respect to the X-axis direction, D
_{4, D 5, D 6,} D 10 0, D 11, D 12, D 13, D 14, D
_20, D _21, D ₂₂ ... to use.

As another example, the following definition formula (d)
Is raised.

Z = ΣΣC _nm XY As an example, when k = 7 (seventh-order term) is considered, when expanded, it can be expressed by the following equation.

Z = C ₂ + C ₃ y + C ₄ | x | + C ₅ y ² + C ₆ y | x | + C ₇ x ² + C ₈ y ³ + C ₉ y ² | x | + C ₁₀ yx ² + C ₁₁ | x ³ | + C ^{_{12 y 4 + C 13 y 3}} | x | + C 14 y 2 x 2 + C 15 y | x 3 | + C 16 x 4 + C 17 y 5 + C 18 y 4 | x | + C 19 y 3 x 2 + C 20 y 2 | x ^{_{3 | + C 21 yx 4 +}} C 22 | x 5 | + C 23 y 6 + C 24 y 5 | x | + C 25 y 4 x 2 + C 26 y 3 | x 3 | + C 27 y 2 x 4 + C 28 y | x 5 | ^{_{+ C 29 x 6 + C 30}} y 7 + C 31 y 6 | x | + C 32 y 5 x 2 + C 33 y 4 | x 3 | + C 34 y 3 x 4 + C 35 y 2 | x 5 | + C 36 yx 6 + C 37 | x ⁷ | (d) In the embodiment of the present invention, the surface shape is represented by a free-form surface using the above equation (a).
It goes without saying that the same operation and effect can be obtained by using the equation (d).

Although the prisms of the optical systems of Examples 1 to 14 are made of plastic, they may be made of glass. In particular, when using a plastic material, it is preferable to use a low moisture absorption material because performance deterioration due to environmental changes is reduced. Embodiments 1 to 5 FIG. 1 shows a YZ sectional view of Embodiment 1 including an axial principal ray. The sectional views of Embodiments 2 to 5 are the same, so that the illustration is omitted.

In all of Examples 1 to 5, the horizontal (X direction) half angle of view is 26.31 °, the vertical (Y direction) half angle of view is 20.35 °,
The F number is 2.8, the image height is 2.69 × 2.015 mm, and the focal length in the X direction Fx of Example 1 is 6.45 mm, and Y is Y.
Focal length in the directional direction Fy = 6.27 mm, focal length in the X direction Fx = 6.05 mm in the second embodiment, focal length in the Y direction Fy = 5.
74 mm, X-direction focal length Fx of Example 3 = 6.23 m
m, focal length in the Y direction Fy = 5.76 mm, X in Example 4
Focal length in direction Fx = 6.83 mm, focal length in Y direction Fy
= 6.70 mm, focal length Fx in the X direction of Example 5 = 6.
67 mm, and the Y direction focal length Fy = 6.46 mm.

The configuration parameters of these embodiments will be described later. The free-form surface is FFS, and the rotationally symmetric aspheric surface is ASS.
The same applies to the following embodiments.

In the first to fifth embodiments, the stop 2, the first transmitting surface 14, the first reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, and the second transmitting surface 15 are arranged in the order in which light passes from the object side. , The first transmitting surface 14, the first reflecting surface 11, the second reflecting surface 12, and the third
Both the reflection surface 13 and the second transmission surface 15 are separate optical action surfaces. These embodiments are prism optical systems of the form shown in FIG.

Regarding the shape of each surface, in the case of the first embodiment, the first transmitting surface 14 is a flat surface, the first reflecting surface 11, the second reflecting surface 12, and the third reflecting surface 13 are free-form surfaces and the second transmitting surface. Reference numeral 15 is a plane.

In the case of the second embodiment, the first transmission surface 14, the first
The reflection surface 11, the second reflection surface 12, and the third reflection surface 13 are free-form surfaces, and the second transmission surface 15 is a flat surface.

In the case of the third embodiment, the first transmitting surface 14 is spherical, the first reflecting surface 11 and the second reflecting surface 12 are free-form surfaces,
The reflecting surface 13 is a rotationally symmetric aspherical surface, and the second transmitting surface 15 is a flat surface.

In the case of the fourth embodiment, the first transmitting surface 14 is spherical, the first reflecting surface 11 is a rotationally symmetric aspherical surface, and the second reflecting surface 12
Is a free-form surface, the third reflecting surface 13 is a rotationally symmetric aspherical surface, and the second transmitting surface 15 is a flat surface.

In the case of the fifth embodiment, the first transmitting surface 14 is spherical, the first reflecting surface 11, the second reflecting surface 12, and the third reflecting surface 13
Is a free-form surface, and the second transmission surface 15 is a flat surface. Example 6
FIG. 2 is a sectional view taken along the line YZ of FIG.
Shown in The sectional views of the seventh to tenth embodiments are the same, so that the illustration is omitted.

In all of Examples 6 to 10, the horizontal (X direction) half angle of view is 26.31 ° and the vertical (Y direction) half angle of view is 20.35.
°, F number 2.8, image height 2.69 × 2.015 mm
And the focal length in the X direction of Example 6 Fx = 5.85 m
m, focal length in the Y direction Fy = 5.67 mm, X in Example 7
Focal length in direction Fx = 5.86 mm, focal length in Y direction Fy
= 5.73 mm, focal length in the X direction Fx of Example 8 = 6.
11 mm, Y direction focal length Fy = 6.00 mm, X direction focal length Fx = 5.85 mm in Example 9, Y direction focal length Fy = 5.71 mm, X direction focal length F in Example 10
x = 6.23 mm, focal length in the Y direction Fy = 6.06 mm
It is.

In the sixth to tenth embodiments, the stop 2, the first transmission surface 14, the first reflection surface 11, the second reflection surface 12, the third reflection surface 13, and the second transmission surface 15 are arranged in the order in which light passes from the object side. , And only one of the positive-power prisms 10 composed of the image plane 3, and the first reflection surface 11 and the second transmission surface 15 are shared by one optical working surface, and the first reflection surface 11 is By total internal reflection. These embodiments are prism optical systems of the form shown in FIG.

Regarding the shape of each surface, in the case of the sixth embodiment, the first transmitting surface 14 is a flat surface, the first reflecting surface 11 (second transmitting surface 15), the second reflecting surface 12, and the third reflecting surface 13 are Consists of free-form surfaces.

In the case of the seventh embodiment, the first transmission surface 14, the first
Reflection surface 11 (second transmission surface 15), second reflection surface 12, third surface
The reflection surface 13 is a free-form surface.

In the case of the eighth embodiment, the first transmitting surface 14 and the second
The reflecting surface 12 and the third reflecting surface 13 are free-form surfaces, the first reflecting surface 1
1 (second transmission surface 15) is a flat surface.

In the case of the ninth embodiment, the first transmitting surface 14 is a flat surface, the first reflecting surface 11 (second transmitting surface 15), and the third reflecting surface 1
3 is a free-form surface, and the second reflection surface 12 is a spherical surface.

In the case of the tenth embodiment, the first transmitting surface 14
The third reflection surface 13 is a free-form surface, the first reflection surface 11 (the second transmission surface 15) is a flat surface, and the second reflection surface 12 is a spherical surface.

FIG. 3 shows a sectional view taken along the line YZ of the eleventh embodiment including the axial principal ray. In the eleventh embodiment, the horizontal (X direction) half angle of view 16.05 °, the vertical (Y direction) half angle of view 22.59 °, F
Number 5.4, image height 2.53 × 3.66 mm,
X direction focal length Fx = 9.51 mm, Y direction focal length F
y = 9.77 mm.

In this embodiment, the order in which light passes from the object side is as follows.
It is composed of only one of the positive power prism 10 including the stop 2, the first transmission surface 14, the second reflection surface 12, the third reflection surface 13, the first reflection surface 11, the second transmission surface 15, and the image surface 3, The first transmission surface 14, the first reflection surface 11, the second reflection surface 12, the third reflection surface 13, and the second transmission surface 15 are all separate optically active surfaces. This embodiment is a prism optical system of the form shown in FIG.

Regarding the shape of each surface, the first transmission surface, the first transmission surface,
The reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, and the second transmitting surface 15 are all free-form surfaces.

FIG. 4 is a sectional view taken along the line YZ of the twelfth embodiment and including the axial principal ray. In the twelfth embodiment, the horizontal (X direction) half angle of view 16.05 °, the vertical (Y direction) half angle of view 22.59 °, F
Number 5.2, image height 2.53 × 3.66 mm,
X direction focal length Fx = 9.14 mm, Y direction focal length F
y = 9.54 mm.

In this embodiment, the order in which light passes from the object side is as follows.
It is composed of only one of the positive power prism 10 including the stop 2, the first transmission surface 14, the second reflection surface 12, the third reflection surface 13, the first reflection surface 11, the second transmission surface 15, and the image surface 3, The first transmission surface 14, the first reflection surface 11, the second reflection surface 12, the third reflection surface 13, and the second transmission surface 15 are all separate optically active surfaces. This embodiment is a prism optical system of the form shown in FIG.

Regarding the shape of each surface, the first transmission surface, the first transmission surface
The reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, and the second transmitting surface 15 are all free-form surfaces.

FIG. 5 is a sectional view of the thirteenth embodiment taken along the line YZ including the axial chief ray. The thirteenth embodiment has a horizontal (X-direction) half angle of view of 16.05 °, a vertical (Y-direction) half angle of view of 22.59 °, F
Number 5.2, image height 2.53 × 3.66 mm,
X direction focal length Fx = 9.22 mm, Y direction focal length F
y = 9.43 mm.

In this embodiment, the order in which light passes from the object side is as follows.
The diaphragm 2, the first transmitting surface 14, the first reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, the second transmitting surface 15, and the positive power prism 10 including the image surface 3; The first transmission surface 14, the first reflection surface 11, the second reflection surface 12, the third reflection surface 13, and the second transmission surface 15 are all separate optically active surfaces. This embodiment is a prism optical system of the form shown in FIG.

Regarding the shape of each surface, the first transmission surface, the first transmission surface,
The reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, and the second transmitting surface 15 are all free-form surfaces.

FIG. 6 is a sectional view taken along the line YZ of the fourteenth embodiment.
FIG. 7 shows a Y sectional view, and FIG. 8 shows an XZ sectional view. This embodiment is eccentric in the three-dimensional direction, and has a horizontal (X direction) half angle of view of 26.31 ° and a vertical (Y direction) half angle of view of 20.30 °.
35 °, f / 2.8, image height 2.69 × 2.015
mm, the focal length in the X direction Fx = 6.44 mm, and the focal length in the Y direction Fy = 6.66 mm.

In this embodiment, the order in which light passes from the object side is as follows.
The diaphragm 2, the first transmitting surface 14, the first reflecting surface 11, the second reflecting surface 12, the third reflecting surface 13, the second transmitting surface 15, and the positive power prism 10 including the image surface 3; The first transmission surface 14, the first reflection surface 11, the second reflection surface 12, the third reflection surface 13, and the second transmission surface 15 are all separate optically active surfaces. In this embodiment, since the image plane 3 is substantially parallel to the YZ plane, it is not any of the prism optical systems of FIG.
It can be said that this is a prism optical system of an intermediate form between FIGS. 28 (a) and 28 (b).

Regarding the shape of each surface, the first transmission surface, the first transmission surface,
The reflection surface 11, the second reflection surface 12, and the third reflection surface 13 are free-form surfaces, and the second transmission surface 15 is a flat surface.

FIG. 9 shows a sectional view taken along the line YZ of the fifteenth embodiment including the axial principal ray. The fifteenth embodiment has a horizontal angle of view of 52.62.
°, a vertical angle of view of 40.68 °, an entrance pupil diameter of 1.16 mm, and a stop 2 and a first transmission surface 1 in order of light passing from the object side.
4, second reflecting surface 12, third reflecting surface 13, first reflecting surface 1
The prism optical system has only one of the positive power prisms 10 including the first, second transmission surfaces 15 and the image plane 3, and has the form shown in FIG. 28 (c). For the shape of each surface, all surfaces 1
Reference numerals 1 to 15 are free-form surfaces.

FIG. 10 is a sectional view taken along the line YZ of FIG. The sixteenth embodiment has a horizontal angle of view of 52.62.
°, a vertical angle of view of 40.68 °, an entrance pupil diameter of 1.16 mm, and a stop 2 and a first transmission surface 1 in order of light passing from the object side.
4, first reflecting surface 11, second reflecting surface 12, third reflecting surface 1
The prism optical system has only one of the positive power prisms 10 including the third transmission surface 15, the second transmission surface 15, and the image surface 3, and has the form shown in FIG. For the shape of each surface, all surfaces 1
Reference numerals 1 to 15 are free-form surfaces.

FIG. 11 is a sectional view taken along the line YZ of the seventeenth embodiment and including the axial principal ray. The seventeenth embodiment has a horizontal angle of view of 52.62.
°, a vertical angle of view of 40.68 °, an entrance pupil diameter of 1.16 mm, and a stop 2 and a first transmission surface 1 in order of light passing from the object side.
4, first reflecting surface 11, second reflecting surface 12, third reflecting surface 1
The prism optical system has only one of the positive power prisms 10 including the third transmission surface 15, the second transmission surface 15, and the image surface 3, and has the form shown in FIG. For the shape of each surface, all surfaces 1
Reference numerals 1 to 15 are free-form surfaces.

FIG. 12 shows a sectional view taken along the line YZ of the eighteenth embodiment including the axial principal ray. The eighteenth embodiment has a horizontal angle of view of 52.62.
°, a vertical angle of view of 40.68 °, an entrance pupil diameter of 1.16 mm, and a stop 2 and a first transmission surface 1 in order of light passing from the object side.
4, second reflecting surface 12, third reflecting surface 13, first reflecting surface 1
The prism optical system has only one of the positive power prisms 10 including the first, second transmission surfaces 15 and the image plane 3, and has the form shown in FIG. 28 (c). For the shape of each surface, all surfaces 1
Reference numerals 1 to 15 are free-form surfaces.

The following is a description of the constituent parameters of Examples 1 to 18 described above. "FFS" in these tables is a free-form surface, "AS
S ″ indicates a rotationally symmetric aspherical surface.

Example 1 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 絞 り (aperture surface) 2 ∞ Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ -2.8456 × 10 ^-3 C ₆ 1.5657 × 10 ^-4 C ₈ -1.7753 × 10 ^-5 C ₁₀ -6.9886 × 10 ^-5 C ₁₁ 2.1291 × 10 ^-4 C ₁₃ 1.8307 × 10 ^-4 C ₁₅ -4.7199 × 10 ^-5 FFS C ₄ -1.8327 × 10 ^-2 C ₆ -1.8487 × 10 ^-2 C ₈ 2.9258 × 10 ^-4 C ₁₀ 1.4926 × 10 ^-4 C ₁₁ -3.4799 × 10 ^-6 C ₁₃ -9.1653 × 10 ^-5 C ₁₅ 3.9643 × 10 ^-5 FFS C ₄ 1.3966 × 10 ^-2 C ₆ 7.7703 × 10 ^-3 C ₈ 9.0528 × 10 ^-4 C ₁₀ 6.3060 × 10 ^-4 C ₁₁ 3.0604 × 10 ^-5 C ₁₃ -6.2281 × 10 ^-5 C ₁₅ 1.3225 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2 ) X 0.00 Y 0.00 Z 1.55 α 49.57 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -8.84 Z 2.97 α -56.01 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -6.68 Z -0.60 α -4.18 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -5.57 Z 5.57 α 22.89 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -4.24 Z 5.22 α 22.89 β 0.00 γ 0.00.

Example 2 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ -2.8604 × 10 ^-2 C ₆ -8.2434 × 10 ^-3 C ₈ -1.1789 × 10 ^-3 C ₁₀ 3.0266 × 10 ^-4 C ₁₁ 1.3795 × 10 ^-3 C ₁₃ 7.3602 × 10 ^-4 C ₁₅ -5.7068 × 10 ^-5 FFS C ₄ -4.6856 × 10 ^-3 C ₆ 3.8 356 × 10 ^-3 C ₈ -2.4166 × 10 ^-4 C ₁₀ -2.3753 × 10 ^-4 C ₁₁ 4.1658 × 10 ^-4 C ₁₃ 9.6865 × 10 ^-5 C ₁₅ 5.0107 × 10 ^-6 FFS C ₄ -1.8828 × 10 ^-2 C ₆ -2.2522 × 10 ^-2 C ₈ 1.8439 × 10 ^-4 C ₁₀ 3.9616 × 10 ^-5 C ₁₁ -1.1708 × 10 ^-5 C ₁₃ -1.1528 × 10 ^-5 C ₁₅ -5.0867 × 10 ^-5 FFS C ₄ 1.4421 × 10 ^-2 C ₆ 3.9229 × 10 ^-3 C ₈ 8.3738 × 10 ^-4 C ₁₀ 5.4482 × 10 ^-4 C ₁₁ 2.8 290 × 10 ^-5 C ₁₃ 8.2023 × 10 ^-5 C ₁₅ 7.6549 × 10 ^-6 Eccentricity (1) X 0.00 Y 0.00 Z 0.01 α 0.00 β 0.00 γ 0.00 side (2) X 0.00 Y 0.00 Z 1.58 α 50.54 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -9.47 Z 3.43 α -53.52 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -7.28 Z -0.67 α -1.56 β 0.00 γ 0.00 eccentricity (5) X 0.00 Y -4.31 Z 5.70 α 25.02 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -4.22 Z 5.88 α 25.02 β 0.00 γ 0.00.

Example 3 Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object plane 面 ∞ 1 ∞ (aperture plane) 2 -22.69 Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 ASS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane ∞ Eccentricity (6) ASS R 34.14 K 0.0000 A 4.8693 × 10 ^-5 B -6.0930 × 10 ^-7 FFS C ₄ -2.8401 × 10 ^{-3 _{C 6 -4.6281 × 10 -4 C 8}} -7.1500 × 10 -4 C 10 -2.5278 × 10 -4 C 11 1.9439 × 10 -4 C 13 -1.3439 × 10 -5 C 15 6.8200 × 10 -6 FFS C 4 - 1.7842 × 10 ^-2 C ₆ -1.3733 × 10 ^-2 C ₈ -4.6091 × 10 ^-4 C ₁₀ -4.5907 × 10 ^-4 C ₁₁ 8.3782 × 10 ^-7 C ₁₃ 1.2077 × 10 ^-5 C ₁₅ 3.6142 × 10 ^-6 Eccentricity (1) X 0.00 Y 0.00 Z 0.02 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 1.57 α 50.02 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -9.38 Z 3.23 α -54.12 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -7.15 Z -0.91 α -2.71 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -4.47 Z 5.44 α 22.88 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -4.28 Z 5.90 α 22.88 β 0.00 γ 0.00.

Example 4 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 -108.73 Eccentricity (1) 1.5254 56.2 3 ASS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 ASS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane ∞ Eccentricity (6) ASS R-612.15 K 0.0000 A 2.4308 × 10 ^-4 B -2.6464 × 10 ^-5 ASS R 35.55 K 0.0000 A 3.3593 × ^{10 -5 B -5.5661 × 10 -7 FFS} C 4 -1.6502 × 10 -2 C 6 -1.1486 × 10 -2 C 8 -3.9715 × 10 -4 C 10 -3.8604 × 10 -4 C 11 -4.5904 × 10 - ⁷ C ₁₃ -8.4324 × 10 ^-6 C ₁₅ -6.9965 × 10 ^-6 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 1.57 α 49.99 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -10.44 Z 3.40 α -54.54 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -8.05 Z -0.89 α -2.88 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -5.35 Z 5.39 α 23.14 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -5.15 Z 5.85 α 23.14 β 0.00 γ 0.00.

Example 5 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 -7.59 Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ -4.1999 × 10 ^-3 C ₆ -3.5807 × 10 ^-4 C ₈ -2.3099 × 10 ^-5 C ₁₀ -7.0001 × 10 ^-5 C ₁₁ 2.6858 × 10 ^-4 C ₁₃ 2.4515 × 10 ^-4 C ₁₅ -3.8114 × 10 ^-5 FFS C ₄ -1.5919 × 10 ^-2 C ₆ -1.5752 × 10 ^-2 C ₈ 6.5926 × 10 ^-5 C ₁₀ -4.0983 × 10 ^-5 C ₁₁ 1.0440 × 10 ^-5 C ₁₃ -6.1805 × 10 ^-5 C ₁₅ 4.3638 × 10 ^-5 FFS C ₄ 1.1587 × 10 ^-2 C ₆ 8.8734 × 10 ^-3 C ₈ 3.7748 × 10 ^-4 C ₁₀ 2.1598 × 10 ^-4 C ₁₁ 3.7788 × 10 ^-5 C ₁₃ -5.5970 × 10 ^-5 C ₁₅ 9.1245 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.06 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 1.63 α 51.16 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -11.08 Z 4.05 α -58.24 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -6.04 Z -2.2 1 α -18.97 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -5.89 Z 7.64 α 0.00 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -5.88 Z 8.14 α 0.00 β 0.00 γ 0.00.

Example 6 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 絞 り (aperture surface) 2 偏 Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS eccentricity (4) 1.5254 56.2 6 FFS eccentricity (2) Image plane ∞ eccentricity (5) FFS C ₄ -5.9679 × 10 ^-3 C ₆ 2.4019 × 10 ^-4 C ₈ -3.8330 × 10 ^-4 C ₁₀ -1.1222 × 10 ^-4 C ₁₁ 1.4163 × 10 ^-4 C ₁₃ 2.8257 × 10 ^-5 C ₁₅ 1.4983 × 10 ^-7 FFS C ₄ -2.2992 × 10 ^-2 C ₆ -2.3681 × 10 ^-2 C ₈ 2.1962 × 10 ^-4 C ₁₀ 2.1918 × 10 ^-4 C ₁₁ -1.9363 × 10 ^-5 C ₁₃ -5.9631 × 10 ^-5 C ₁₅ -8.9282 × 10 ^-5 FFS C ₄ 1.1980 × 10 ^-2 C ₆ 4.0025 × 10 ^-3 C ₈ 1.0101 × 10 ^-3 C ₁₀ 8.7909 × 10 ^-4 C ₁₁ 1.5009 × 10 ^-5 C ₁₃ 5.5050 × 10 ^-5 C ₁₅ 3.1295 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.21 α 58.51 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -5.15 Z 4.83 α -37.71 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -4.29 Z 0.9 1 α 23.06 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -0.16 Z 3.43 α 58.59 β 0.00 γ 0.00.

Example 7 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS eccentricity (4) 1.5254 56.2 6 FFS eccentricity (2) Image plane 偏 eccentricity (5) FFS C ₄ 6.4229 × 10 ^-3 C ₆ 2.3844 × 10 ^-3 C ₈ -2.1315 × 10 ^-3 C ₁₀ 2.3072 × 10 ^-3 C ₁₁ 3.2942 × 10 ^-4 C ₁₃ -5.1480 × 10 ^-4 C ₁₅ 1.6767 × 10 ^-4 FFS C ₄ -5.5298 × 10 ^-3 C ₆ 1.3334 × 10 ^-4 C ₈ -5.3766 × 10 ^-4 C ₁₀ 5.1448 × 10 ^-5 C ₁₁ 1.9177 × 10 ^-4 C ₁₃ 6.4722 × 10 ^-6 C ₁₅ 1.3621 × 10 ^-6 FFS C ₄ -2.3007 × 10 ^-2 C ₆ -2.5359 × 10 ^-2 C ₈ 2.2390 × 10 ^-4 C ₁₀ 6.6366 × 10 ^-4 C ₁₁ -1.4415 × 10 ^-5 C ₁₃ -1.1004 × 10 ^-4 C ₁₅ -3.1372 × 10 ^-5 FFS C ₄ 1.1579 × 10 ^-2 C ₆ 1.2198 × 10 ^-3 C ₈ 1.0524 × 10 ^-3 C ₁₀ 1.2232 × 10 ^-3 C ₁₁ 1.6014 × 10 ^-5 C ₁₃ -1.3136 × 10 ^-5 C ₁₅ 1.1966 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.11 α 59.64 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -5.07 Z 4.95 α -36.60 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -4.23 Z 1.15 α 23.57 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -0.23 Z 3.49 α 59.63 β 0.00 γ 0.00.

Example 8 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 ∞ Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (2) Image plane ∞ Eccentricity (5) FFS C ₄ -4.0886 × 10 ^-3 C ₆ -2.1173 × 10 ^-2 C ₈ 2.0808 × 10 ^-3 C ₁₀ 2.5747 × 10 ^-3 C ₁₁ -2.6038 × 10 ^-4 C ₁₃ -1.3110 × 10 ^-3 C ₁₅ -7.5816 × 10 ^-5 FFS C ₄ -2.3709 × 10 ^-2 C ₆ -2.5799 × 10 ^-2 C ₈ -9.7990 × 10 ^-5 C ₁₀ 2.1528 × 10 ^-4 C ₁₁ -1.5683 × 10 ^-5 C ₁₃ -9.2 260 × 10 ^-5 C ₁₅ -6.1702 × 10 ^-5 FFS C ₄ 1.0474 × 10 ^-2 C ₆ -5.4930 × 10 ^-4 C ₈ 7.3001 × 10 ^-4 C ₁₀ 4.8 564 × 10 ^-4 C ₁₁ 1.8 197 × 10 ^-5 C ₁₃ -9.0 325 × 10 ^-6 C ₁₅ 2.8638 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.02 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.24 α 61.25 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -5.81 Z 5.94 α -37.11 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -4.45 Z 1.43 α 25.57 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 0.40 Z 3.34 α 72.21 β 0.00 γ 0.00.

Example 9 Surface Number Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 ∞ Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 -21.28 Eccentricity (3) 1.5254 56.2 5 FFS eccentricity (4) 1.5254 56.2 6 FFS eccentricity (2) Image plane ∞ eccentricity (5) FFS C ₄ -5.0524 × 10 ^-3 C ₆ 7.7975 × 10 ^-5 C ₈ -4.6499 × 10 ^-4 C _10- 1.0056 × 10 ^-4 C ₁₁ 8.5596 × 10 ^-5 C ₁₃ 1.3645 × 10 ^-5 C ₁₅ -9.0784 × 10 ^-6 FFS C ₄ 1.1555 × 10 ^-2 C ₆ 4.3107 × 10 ^-3 C ₈ 7.2247 × 10 ^-4 C ₁₀ 5.7015 × 10 ^-4 C ₁₁ -1.2252 × 10 ^-5 C ₁₃ 1.0965 × 10 ^-4 C ₁₅ 9.5 912 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.15 α 60.28 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -5.22 Z 5.23 α -36.09 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -4.31 Z 1.22 α 24.46 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -0.09 Z 3.48 α 62.55 β 0.00 γ 0.00.

Example 10 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 ∞ Eccentricity (2) 1.5254 56.2 4 -21.90 Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (2) Image plane ∞ Eccentricity (5) FFS C ₄ 2.7171 × 10 ^-3 C ₆ -1.2638 × 10 ^-2 C ₈ 1.3368 × 10 ^-3 C ₁₀ 2.2 565 × 10 ^-3 C ₁₁ -1.9146 × 10 ^-4 C ₁₃ -9.1613 × 10 ^-4 C ₁₅ 1.5462 × 10 ^-4 FFS C ₄ 1.0790 × 10 ^-2 C ₆ 2.8634 × 10 ^-3 C ₈ 7.8451 × 10 ^-4 C ₁₀ 3.5327 × 10 ^-4 C ₁₁ 1.9617 × 10 ^-7 C ₁₃ 5.6526 × 10 ^-5 C ₁₅ 4.9 131 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.01 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.24 α 61.27 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -5.60 Z 5.81 α -35.94 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -4.47 Z 1.41 α 26.13 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 0.31 Z 3.43 α 70.80 β 0.00 γ 0.00.

Example 11 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ -8.9127 × 10 ^-2 C ₆ -9.5356 × 10 ^-2 C ₈ -3.5793 × 10 ^-3 C _10- 4.0456 × 10 ^-3 C ₁₁ -1.9833 × 10 ^-4 C ₁₃ -4.4235 × 10 ^-3 FFS C ₄ -1.0381 × 10 ^-2 C ₆ -1.1052 × 10 ^-2 C ₈ -2.1578 × 10 ^-4 C ₁₀ -1.5722 × 10 ^-4 C ₁₁ 9.6190 × 10 ^-6 C ₁₃ -6.0980 × 10 ^-6 FFS C ₄ 7.7051 × 10 ^-3 C ₆ 4.6995 × 10 ^-3 C ₈ -1.5114 × 10 ^-4 C ₁₀ -8.3040 × 10 ^-5 C ₁₁ 1.1415 × 10 ^-5 C ₁₃ -6.5985 × 10 ^-6 FFS C ₄ 2.1221 × 10 ^-3 C ₆ 2.5841 × 10 ^-4 C ₈ -1.0538 × 10 ^-4 C ₁₀ -2.2873 × 10 ^-5 C ₁₁ 2.0472 × 10 ^-5 C ₁₃ -5.9609 × 10 ^-6 FFS C ₄ 7.0082 × 10 ^-2 C ₆ 5.8372 × 10 ^-2 C ₈ 7.8413 × 10 ^-4 C ₁₀ 6.7075 × 10 ^-4 C ₁₁ 6.9278 × 10 ^-4 C ₁₃ 5.5357 × 10 ^-5 Center (1) X 0.00 Y 0.00 Z 0.96 α -3.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y -0.32 Z 18.85 α 14.30 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -6.61 Z 7.80 α 55.73 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 10.31 Z 10.23 α -43.40 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 11.42 Z 15.78 α 13.26 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 11.68 Z 17.19 α 10.37 β 0.00 γ 0.00 .

Example 12 Surface No. Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 絞 り (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS eccentricity (4) 1.5254 56.2 6 FFS eccentricity (5) Image plane ∞ eccentricity (6) FFS C ₄ -7.9211 × 10 ^-2 C ₆ -1.0146 × 10 ^-1 C ₈ 2.4534 × 10 ^-3 C ₁₀ -2.0643 × 10 ^-3 C ₁₁ -9.3114 × 10 ^-4 C ₁₃ -2.4386 × 10 ^-3 FFS C ₄ -1.1469 × 10 ^-2 C ₆ -1.3911 × 10 ^-2 C ₈ 2.6114 × 10 ^-4 C ₁₀ -2.3753 × 10 ^-4 C ₁₁ -1.8850 × 10 ^-6 C ₁₃ 7.9076 × 10 ^-6 FFS C ₄ 1.1485 × 10 ^-2 C ₆ 5.7073 × 10 ^-3 C ₈ 4.7344 × 10 ^-4 C ₁₀ -1.2553 × 10 ^-4 C ₁₁ 5.8436 × 10 ^-6 C ₁₃ 5.9345 × 10 ^-6 FFS C ₄ 5.8635 × 10 ^-3 C ₆ 6.9 275 × 10 ^-3 C ₈ 1.0101 × 10 ^-3 C ₁₀ 4.0640 × 10 ^-5 C ₁₁ 2.5761 × 10 ^-5 C ₁₃ 5.0653 × 10 ^-6 FFS C ₄ -1.7625 × 10 ^-2 C ₆ 3.7708 × 10 ^-2 C ₈ 2.2953 × 10 ^-3 C ₁₀ 1.3909 × 10 ^-3 C ₁₁ -6.1893 × 10 ^-5 C ₁₃ -4.3469 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z 0.94 α -0.36 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y -0.03 Z 13.57 α 18.76 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -4.72 Z 7.48 α 69.26 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 8.98 Z 4.85 α 55.93 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 7.93 Z -0.55 α 6.53 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 7.81 Z -1.03 α 13.34 β 0.00 γ 0.00 .

Example 13 Surface No. Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS eccentricity (4) 1.5254 56.2 6 FFS eccentricity (5) Image plane ∞ eccentricity (6) FFS C ₄ -6.7629 × 10 ^-3 C ₆ -7.5417 × 10 ^-2 C ₈ 7.6012 × 10 ^-3 C ₁₀ -2.2552 _{^{× 10 -3 C 11 -1.0100 × 10}} -3 C 13 -8.0963 × 10 -4 FFS C 4 4.2258 × 10 -3 C 6 -6.8525 × 10 -3 C 8 1.4334 × 10 -3 C 10 -5.8020 × 10 - ⁵ C ₁₁ -1.8024 × 10 ^-4 C ₁₃ 1.4204 × 10 ^-4 FFS C ₄ 1.2370 × 10 ^-2 C ₆ 9.4506 × 10 ^-3 C ₈ 2.8 709 × 10 ^-4 C ₁₀ 2.6798 × 10 ^-4 C ₁₁ 1.9467 × 10 ^-6 C ₁₃ 1.8642 × 10 ^-5 FFS C ₄ -1.0905 × 10 ^-2 C ₆ -6.1974 × 10 ^-3 C ₈ -1.5764 × 10 ^-5 C ₁₀ 7.3750 × 10 ^-5 C ₁₁ 2.4054 × 10 ^-6 C ₁₃ 2.0622 × 10 ^-5 FFS C ₄ -6.7856 × 10 ^-2 C ₆ -3.2508 × 10 ^-2 C ₈ -3.3933 × 10 ^-4 C ₁₀ -1.2625 × 10 ^-4 C ₁₁ -1.8800 × 10 ^-4 C ₁₃ 2.7460 × ^10-5 Heart (1) X 0.00 Y 0.00 Z 0.93 α -0.02 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 3.83 α 45.91 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -14.44 Z 4.29 α 64.81 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -9.99 Z 10.02 α 11.46 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y -7.15 Z -0.67 α -17.68 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y -6.87 Z -1.85 α- 13.40 β 0.00 γ 0.00.

Example 14 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.5254 56.2 3 FFS Eccentricity (2) 1.5254 56.2 4 FFS Eccentricity (3) 1.5254 56.2 5 FFS Eccentricity (4) 1.5254 56.2 6 ∞ Eccentricity (5) Image plane 偏 Eccentricity (6) FFS C ₄ -3.0124 × 10 ^-2 C ₆ 2.9830 × 10 ^-3 C ₇ 1.5193 × 10 ^-3 C ₈ -1.3685 × 10 ^-3 C ₉ 2.9923 × 10 ^-3 C ₁₀ 7.0950 × 10 ^-3 C ₁₁ 2.2 180 × 10 ^-3 C ₁₂ -1.0459 × 10 ^-3 C ₁₃ 7.2719 × 10 ^-4 C ₁₄ 1.4258 × 10 ^-3 C ₁₅ 4.1441 × 10 ^-3 FFS C ₄ -2.2499 × 10 ^-4 C ₆ 6.6561 × 10 ^-3 C ₇ 6.3267 × 10 ^-4 C ₈ -9.4 330 × 10 ^-5 C ₉ 5.5101 × 10 ^-4 C ₁₀ 7.1597 × 10 ^-4 C ₁₁ 4.9038 × 10 ^-4 C ₁₂ -1.8 192 × 10 ^-4 C ₁₃ 3.9277 × 10 ^-4 C ₁₄ 1.4359 × 10 ^-4 C ₁₅ 1.1825 × 10 ^-4 FFS C ₄ 1.4136 × 10 ^-2 C ₆ 6.5846 × 10 ^-3 C ₇ 1.9472 × 10 ^-6 C ₈ -1.3 280 × 10 ^-4 C ₉ -6.1137 × 10 ^-5 C ₁₀ -4.0691 × 10 ^-4 C ₁₁ -1.1089 × 10 ^-5 C ₁₂ 6.0764 × 10 ^-6 C ₁₃ 7.8257 × 10 ^-5 C ₁₄ 7.2012 × 10 ^-6 C ₁₅ 2.8993 × 10 ^-7 FFS C ₄ -1.3495 × 10 ^-2 C ₆ -1.6500 × 10 ^-2 C ₇ 2.2484 × 10 ^-5 C ₈ 1.3196 × 10 ^-4 C ₉ -5.8042 × 10 ^-5 C ₁₀ -8.0432 × 10 ^-5 C ₁₁ -2.3096 × 10 ^-5 C ₁₂ 4.6876 × 10 ^-6 C ₁₃ 6.6176 × 10 ^-5 C ₁₄ 6.1573 × 10 ^-6 C ₁₅ -1.1366 × 10 ^-5 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 2.00 α 45.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -13.70 Z 2.00 α 90.00 β 21.82 γ 90.00 Eccentricity (4) X- 5.70 Y -7.72 Z 2.00 α 90.00 β 67.12 γ 90.00 Eccentricity (5) X 5.54 Y -7.60 Z 2.00 α 0.00 β 89.76 γ 0.00 Eccentricity (6) X 5.74 Y -7.60 Z 2.00 α 0.00 β 89.76 γ 90.00.

Example 15 Surface No. Curvature Radius Surface Spacing Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.4924 57.6 3 FFS Eccentricity (2) 1.4924 57.6 4 FFS Eccentricity (3) 1.4924 57.6 5 FFS eccentricity (4) 1.4924 57.6 6 FFS eccentricity (5) Image plane ∞ eccentricity (6) FFS C ₄ -1.5543 × 10 ^-1 C ₆ -1.5231 × 10 ^-1 C ₈ 7.5854 × 10 ^-3 C ₁₀ 9.8288 × ^{_{10 -3 C 11 -2.2595 × 10 -2}} C 13 -2.9465 × 10 -2 C 15 -1.0797 × 10 -2 FFS C 4 -6.7031 × 10 -3 C 6 -5.0410 × 10 -3 C 8 8.8505 × 10 - ^{_{5 C 10 5.8009 × 10 -4 C}} 11 1.9741 × 10 -5 C 13 3.2007 × 10 -6 C 15 4.0397 × 10 -5 FFS C 4 2.3315 × 10 -2 C 6 1.9365 × 10 -2 C 8 2.2124 × 10 - ⁴ C ₁₀ 4.6907 × 10 ^-4 C ₁₁ 3.5154 × 10 ^-5 C ₁₃ 4.2249 × 10 ^-5 C ₁₅ 1.6809 × 10 ^-5 FFS C ₄ -1.9358 × 10 ^-2 C ₆ -1.0917 × 10 ^-2 C ₈ 2.2536 × 10 ^-3 C ₁₀ 1.4078 × 10 ^-3 C ₁₁ -1.3627 × 10 ^-5 C ₁₃ -1.5958 × 10 ^-4 C ₁₅ -7.5403 × 10 ^-5 FFS C ₄ 1.4862 × 10 ^-1 C ₆ 4.7792 × 10 ^-2 C ₈ 2.9224 × 10 ^-2 C ₁₀ -2.6156 × 10 ^-2 C ₁₁ -5.0410 × 10 ^-2 C ₁₃ -5.2568 × 10 ^-2 C ₁₅ -1.7527 × 10 ^-2 Eccentricity (1) X 0.00 Y 0.00 Z 0.60 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 10.00 α 23.98 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -3.89 Z 6.49 α 74.07 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 5.72 Z 4.77 α 137.79 β 0.00 γ 0.00 eccentricity (5) X 0.00 Y 5.39 Z 8.82 α 173.01 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 5.36 Z 9.32 α -180.00 β 0.00 γ 0.00.

Example 16 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.4924 57.6 3 FFS Eccentricity (2) 1.4924 57.6 4 FFS Eccentricity (3) 1.4924 57.6 5 FFS eccentricity (4) 1.4924 57.6 6 FFS eccentricity (5) Image plane ∞ eccentricity (6) FFS C ₄ -1.5632 × 10 ^-1 C ₆ -1.8074 × 10 ^-1 C ₈ 2.4472 × 10 ^-3 C ₁₀ 1.7187 × 10 ^-2 C ₁₁ 5.0412 × 10 ^-3 C ₁₃ -3.4775 × 10 ^-4 C ₁₅ 1.4880 × 10 ^-3 FFS C ₄ 2.4040 × 10 ^-3 C ₆ 3.5551 × 10 ^-3 C ₈ -2.0595 × 10 ^-3 C ₁₀ -2.9615 × 10 ^-5 C ₁₁ 1.6098 × 10 ^-3 C ₁₃ 1.1678 × 10 ^-3 C ₁₅ 1.5439 × 10 ^-4 FFS C ₄ 1.4129 × 10 ^-2 C ₆ 1.7198 × 10 ^-2 C ₈ -3.0988 × 10 ^-4 C ₁₀ -2.0981 × 10 ^-4 C ₁₁ -3.3991 × 10 ^-5 C ₁₃ -4.1263 × 10 ^-5 C ₁₅ -5.9528 × 10 ^-6 FFS C ₄ -1.6871 × 10 ^-2 C ₆ -8.3453 × 10 ^-3 C ₈ -5.5447 × 10 ^-4 C ₁₀ -6.2485 × 10 ^-4 C ₁₁ -4.7156 × 10 ^-5 C ₁₃ -7.0576 × 10 ^-5 C ₁₅ -3.2320 × 10 ^-5 FFS C ₄ 5.5443 × 10 ^-2 C ₆ 5.8343 × 10 ^-2 C ₈ -9.9501 × 10 ^-5 C ₁₀ -1.7328 × 10 ^-3 C ₁₁ -5.5 914 × 10 ^-3 C ₁₃ -1.2587 × 10 ^-2 C ₁₅ -4.6614 × 10 ^-3 Eccentricity (1) X 0.00 Y 0.00 Z 0.14 α 7.30 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.09 Z 2.36 α -40.95 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 11.67 Z 1.21 α -109.72 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 6.60 Z- 3.88 α -156.60 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 6.97 Z 7.14 α 177.15 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 7.12 Z 9.13 α -175.71 β 0.00 γ 0.00 Example 17 Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.4924 57.6 3 FFS Eccentricity (2) 1.4924 57.6 4 FFS Eccentricity (3) 1.4924 57.6 5 FFS Eccentricity (4) 1.4924 57.6 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ -1.4849 × 10 ^-1 C ₆ -1.6359 × 10 ^-1 C ₈ 8.6775 × 10 ^-4 C ₁₀ 9.8187 × 10 ^-3 C ₁₁ 1.1462 × 10 ^-2 C ₁₃ 1.3163 × 10 ^-2 C ₁₅ -3.4637 × 10 ^-3 FFS C ₄ 9.6401 × 10 ^-3 C ₆ 9.6477 × 10 ^-3 C _{8 ^{-1.4638 × 10 -3 C 10 -4.3514 ×}} 10 -5 C 11 2.4473 × 10 -3 C 13 2.1953 × 10 -3 C 15 -4.8828 × 10 -5 FFS C 4 1.8071 × 10 -2 C 6 1.7573 × 10 - ² C ₈ 5.9585 × 10 ^-5 C ₁₀ 9.6883 × 10 ^-6 C ₁₁ 3.1615 × 10 ^-5 C ₁₃ 2.3 503 × 10 ^-5 C ₁₅ 6.2462 × 10 ^-6 FFS C ₄ -1.4177 × 10 ^-2 C ₆ -9.9094 × 10 ^-3 C ₈ 6.1254 × 10 ^-4 C ₁₀ 3.9896 × 10 ^-4 C ₁₁ 9.4960 × 10 ^-6 C ₁₃ -3.3981 × 10 ^-5 C ₁₅ -8.9917 × 10 ^-6 FFS C ₄ 5.4723 × 10 ^-2 C ₆ 1.2791 × 10 ^-2 C ₈ 8.8441 × 10 ^-3 C ₁₀ 5.6452 × 10 ^-4 C ₁₁ -4.9607 × 10 ^-3 C ₁₃ -1.5671 × 10 ^-2 C ₁₅ -1.6314 × 10 ^-3 Eccentricity (1) X 0.00 Y 0.00 Z 0.10 α 4.51 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.06 Z 2.50 α -34.06 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 10.62 Z -1.43 α -44.89 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 7.97 Z 5.77 α 2.28 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 3.46 Z -4.01 α 22.75 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 2.59 Z -5.81 α 25.72 β 0.00 γ 0.00.

Example 18 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ ∞ 1 ∞ (aperture surface) 2 FFS Eccentricity (1) 1.4924 57.6 3 FFS Eccentricity (2) 1.4924 57.6 4 FFS Eccentricity (3) 1.4924 57.6 5 FFS eccentricity (4) 1.4924 57.6 6 FFS eccentricity (5) Image plane ∞ eccentricity (6) FFS C ₄ -7.6743 × 10 ^-2 C ₆ -2.6215 × 10 ^-1 C ₈ 9.3908 × 10 ^-3 C ₁₀ -7.4603 _{^{× 10 -3 C 11 -1.0213 × 10}} -2 C 13 -3.6797 × 10 -2 C 15 -7.6107 × 10 -3 FFS C 4 1.8195 × 10 -2 C 6 -2.5656 × 10 -2 C 8 8.3078 × 10 - ⁴ C ₁₀ -3.9942 × 10 ^-4 C ₁₁ -2.0392 × 10 ^-5 C ₁₃ -2.9099 × 10 ^-6 C ₁₅ 3.5222 × 10 ^-5 FFS C ₄ 2.5291 × 10 ^-2 C ₆ -1.3364 × 10 ^-2 C ₈ -1.0393 × 10 ^-3 C ₁₀ -1.7946 × 10 ^-3 C ₁₁ 1.4928 × 10 ^-5 C ₁₃ 5.5525 × 10 ^-5 C ₁₅ -5.6868 × 10 ^-5 FFS C ₄ -2.9976 × 10 ^-2 C ₆ -1.8899 × 10 ^-2 C ₈ 1.7878 × 10 ^-3 C ₁₀ 1.2045 × 10 ^-4 C ₁₁ 9.1833 × 10 ^-6 C ₁₃ -1.0484 × 10 ^-4 C ₁₅ -4.5162 × 10 ^-5 FFS C ₄ -8.7521 × 10 ^-2 C ₆ -4.1023 × 10 ^-2 C ₈ 8.6326 × 10 ^-3 C ₁₀ 1.4606 × 10 ^-2 C ₁₁ -5.9850 × 10 ^-4 C ₁₃ -3.9008 × 10 ^-3 C ₁₅ 1.3820 × 10 ^-4 Eccentricity (1) X 0.00 Y 0.00 Z 0.17 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.00 Z 11.50 α 12.99 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y -3.02 Z 5.31 α 60.36 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 7.13 Z 4.46 α 138.95 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 7.42 Z 9.55 α -170.45 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 7.42 Z 12.55. α -180.00 β 0.00 γ 0.00 Next, the lateral aberration diagrams of the above-described Examples 2, 7, and 15 are shown in FIGS. 13, 14, and 15, respectively. In these lateral aberration diagrams, the numbers in parentheses indicate (horizontal (X direction) angle of view, vertical (Y direction) angle of view), and indicate the lateral aberration at that angle of view.

Next, the conditional expressions (1) to (1)
Θ for 0)₁, Θ_Two, Θ_Three, Θ _Four, P2x / Px,
The values of P3x / Px, P2y / Py, P3y / Py are as follows:
Shown in

Θ ₁ θ ₂ θ ₃ θ ₄ p2x / Px p3x / Px p2y / Py p3y / Py Example 1 24.86 26.97 49.57 76.34 0.473 0.360 0.463 0.195 Example 2 25.41 26.55 50.54 76.08 0.456 0.349 0.517 0.090 Example 3 25.70 25.99 50.02 77.18 0.445 0.365 0.317 0.365 Example 4 25.48 26.18 49.99 76.69 0.451 0.384 0.308 0.384 Example 5 19.44 19.83 51.16 78.54 0.425 0.309 0.407 0.229 Example 6 25.28 35.49 58.51 58.46 0.538 0.280 0.537 0.091 Example 7 24.13 36.05 59.64 59.66 59.64 59 Example 8 20.39 42.29 61.25 54.64 0.580 0.256 0.619 -0.013 Example 9 23.34 37.21 60.28 58.89 0.549 0.270 0.549 0.098 Example 10 21.52 40.55 61.27 55.86 0.569 0.269 0.569 0.069 Example 11 15.34 26.10 54.77 82.87 0.395 0.293 0.432 0.188 Example 62 44.95 79.25 0.436 0.437 0.544 0.223 Example 13 24.44 26.81 45.92 76.95 0.470 0.415 0.369 0.242 Example 14 21.82 23.48 45 43.64 0.364 0.348 0.176 0.440 Example 15 20.42 26.74 40.39 85.67 0.066 0.433 0.103 0.346 Example 16 25.41 21.47 43.36 0 357 0.364 0.177 Example 17 24.72 22.45 35.55 85.66 0.374 0.293 0.367 0.207 Example 18 12.99 34.38 44.21 85.26 -0.382 0.531 0.544 -0.283.

The imaging optical system of the present invention as described above can be used in a photographing apparatus for forming an object image and receiving the image with an image pickup device such as a CCD or a silver halide film for photographing, in particular, a camera. it can. It can also be used as an observation device for observing an object image through an eyepiece, particularly as an objective optical system for a finder section of a camera. Further, it can also be used as an imaging optical system for an optical device using a small imaging element such as an endoscope. less than,
The embodiment is illustrated.

FIGS. 16 to 18 are conceptual diagrams showing a configuration in which the imaging optical system of the present invention is incorporated in an objective optical system of a finder section of an electronic camera. 16 is a front perspective view showing the appearance of the electronic camera 40, FIG. 17 is a rear perspective view of the same, and FIG. Electronic camera 40
In the case of this example, includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, a shutter 45, a flash 46, a liquid crystal display monitor 47, and the like. When the shutter 45 is pressed, the photographing is performed through the photographing objective optical system 48 in conjunction therewith. An object image formed by the photographing objective optical system 48 is formed on the imaging surface 50 of the CCD 49 via a filter 51 such as a low-pass filter or an infrared cut filter. This CCD4
The object image received at 9 is passed through a processing means 52 as an electronic image to a liquid crystal display monitor 47 provided on the back of the camera.
Will be displayed. Further, a memory or the like is arranged in the processing means 52, and a captured electronic image can be recorded. This memory may be provided separately from the processing means 52, or may be configured to perform electronic recording and writing using a floppy disk or the like. Further, a silver halide camera in which a silver halide film is arranged in place of the CCD 49 may be configured.

Further, on the finder optical path 44,
A finder objective optical system 53 is provided, and the finder objective optical system 53 includes a cover lens 54,
The diaphragm 2, a prism 10, and a focusing lens 66 are used, and a prism optical system of the form shown in FIG. 28C is used as an imaging optical system from the diaphragm 2 to the prism 10. Also, a cover lens 54 used as a cover member
Is a lens having a negative power, which enlarges the angle of view. The position of the focusing lens 66 disposed behind the prism 10 is adjustable in the front-rear direction of the optical axis, and is used for adjusting the focus of the finder objective optical system 53. The object image formed on the image plane 67 by the finder objective optical system 53 is formed on a field frame 57 of a Porro prism 55 which is an image erecting member.
The field frame 57 is provided on the first reflection surface 5 of the Porro prism 55.
6 and the second reflection surface 58 are separated from each other and disposed therebetween. Behind the polyprism 55, an eyepiece optical system 59 for guiding the erect image into the observer's eyeball E is disposed.

In the camera 40 configured as described above, the finder objective optical system 53 can be configured with a small number of optical members, high performance and low cost can be realized, and the optical path itself of the objective optical system 53 can be bent. Therefore, the degree of freedom of arrangement inside the camera increases, which is advantageous in design.

Although the configuration of the photographing objective optical system 48 has not been mentioned in the configuration of FIG. 18, the prism for use in the present invention is not limited to the refraction type coaxial optical system but may be a prism of the present invention. Of course, it is also possible to use any type of imaging optical system consisting of ten.

Next, FIG. 19 is a conceptual diagram showing a configuration in which the image forming optical system of the present invention is incorporated in the objective optical system 48 of the photographing section of the electronic camera 40. In the case of this example, the prismatic optical system of the form shown in FIG. 28A is used as the photographing objective optical system 48 arranged on the photographing optical path 42. The object image formed by this photographing objective optical system is a low-pass filter,
CC through a filter 51 such as an infrared cut filter
D49 is formed on the imaging surface 50. The object image received by the CCD 49 is displayed as an electronic image on a liquid crystal display (LCD) 60 via the processing means 52. Also,
The processing unit 52 also controls a recording unit 61 that records an object image captured by the CCD 49 as electronic information. L
The image displayed on the CD 60 is guided to the observer's eyeball E via the eyepiece optical system 59. The eyepiece optical system 59 is composed of a decentered prism, and in this example, the entrance surface 62 and the reflection surface 6
3 and a surface 64 for both reflection and refraction. Also, in the surfaces 63 and 64 having two reflecting actions,
At least one surface, desirably both surfaces, is constituted by a plane-symmetric free-form surface having only one plane of symmetry for applying power to the light beam and correcting eccentric aberration. The only plane of symmetry is the prism 2 of the objective optical system 48 for photographing.
It is formed on substantially the same plane as the only plane of symmetry of the plane-symmetric free-form surfaces of the surfaces 1 and 22. Further, the photographing objective optical system 48 may include another lens (positive lens, negative lens) on the object side, between the prisms, or on the image side of the prisms 21 and 22 as a component thereof.

In the camera 40 thus configured, the photographing objective optical system 48 can be composed of a small number of optical members, high performance and low cost can be realized, and the entire optical system can be arranged on the same plane. Thus, it is possible to realize the thickness of the thickness in the direction perpendicular to the arrangement plane.

In this example, a parallel flat plate is arranged as the cover member 65 of the photographing objective optical system 48, but a lens having power may be used as in the previous example.

Here, without providing the cover member, the surface of the image forming optical system according to the present invention which is disposed closest to the object can also be used as the cover member. In this example, the surface closest to the object is the incident surface of the prism 10. However, since this incident surface is eccentrically arranged with respect to the optical axis, if this surface is arranged in front of the camera, the photographing center of the camera 40 is shifted from itself when viewed from the subject side. This is an illusion (similar to a general camera, it is usual to sense that the image is taken in the vertical direction of the incident surface), giving a sense of incongruity. Therefore, when the surface closest to the object side of the imaging optical system is an eccentric surface as in the present example, providing the cover member 65 (or the cover lens 54) may cause an uncomfortable feeling when viewed from the subject side. It is desirable to be able to receive photography with the same feeling as an existing camera without feeling.

Next, FIG. 20 shows an image forming optical system according to the present invention as an objective optical system 82 of an observation system of an electronic endoscope, and an image forming optical system according to the present invention as an eyepiece optical system of an observation system of an electronic endoscope. The conceptual diagram of the structure incorporated in the system 87 is shown. In this example, the objective optical system 82 of the observation system uses a prism optical system in the form of FIG. 28C, and the eyepiece optical system 87 uses the prism optical system in the form of FIG. 28A. As shown in FIG. 20A, the electronic endoscope includes an electronic endoscope 71, a light source device 72 that supplies illumination light, and a video processor 73 that performs signal processing corresponding to the electronic endoscope 71. A monitor 74 for displaying video signals output from the video processor 73; a VTR deck 75 connected to the video processor 73 for recording video signals and the like; and a video disk 76, and printing the video signals as video. Video printer 77 and a head-mounted image display device (HM
D) 78, the distal end portion 80 of the insertion portion 79 of the electronic endoscope 71, and the eyepiece portion 81 thereof are arranged as shown in FIG.
It is configured as shown in FIG. The light beam illuminated from the light source device 72 passes through the light guide fiber bundle 88 and illuminates the observation site by the illumination objective optical system 89.
Then, light from this observation site is formed as an object image by the observation objective optical system 82 via the cover member 85. This object image is formed on the imaging surface of the CCD 84 via a filter 83 such as a low-pass filter or an infrared cut filter. Furthermore, this object image is a CCD
The video signal is converted by the video processor 84 into a video signal. The video signal is directly displayed on a monitor 74 by a video processor 73 shown in FIG.
It is recorded on a video disk 76 and printed out from a video printer 77 as a video. Also, H
The information is displayed on the image display element of the MD 78 and displayed to the wearer of the HMD 78. At the same time, the image signal converted by the CCD 84 is displayed as an electronic image on a liquid crystal display (LCD) 86 of the eyepiece 81, and the displayed image passes through an eyepiece optical system 87 comprising an observation optical system of the present invention. It is led to the eyeball E.

The endoscope thus configured can be configured with a small number of optical members, realizing high performance and low cost. In addition, the objective optical system 80 is arranged in the longitudinal direction of the endoscope.
The above effect can be obtained without inhibiting the reduction in diameter.

Incidentally, the imaging optical system can be used also as a projection optical system by reversing the optical path. FIG.
FIG. 1 shows a conceptual diagram of a configuration in which a prism optical system according to the present invention is used as a projection optical system 96 of a presentation system in which a personal computer 90 and a liquid crystal projector 91 are combined. In this example, the projection optical system 96 uses a prism optical system of the form shown in FIG. In the figure, image / document data created on a personal computer 90 branches from a monitor output and
Is output to the processing control unit 98. LCD projector 91
The input data is processed by the processing control unit 98, and is output to the liquid crystal panel (LCP) 93. The liquid crystal panel 93 displays an image corresponding to the input image data. Then, after the amount of light from the light source 92 is determined by the gradation of the image displayed on the liquid crystal panel 93, the field lens 9 disposed immediately before the liquid crystal panel 93.
The light is projected onto a screen 97 via a projection optical system 96 including a prism 5, a prism 10 constituting the imaging optical system of the present invention, and a cover lens 94 as a positive lens.

The projector configured as described above can be configured with a small number of optical members, can achieve high performance and low cost, and can be downsized.

Next, FIGS. 22 to 24 are conceptual diagrams showing a configuration in which the image forming optical system of the present invention is built in a personal computer as an example of an information processing apparatus.

FIG. 22 is a front perspective view of the personal computer 300 with the cover opened, and FIG.
3 is a sectional view, and FIG. 24 is a side view of the state of FIG. As shown in FIGS. 22 to 24, a personal computer 300 is provided with a keyboard 301 for a processor to input information from outside.
And information processing means and recording means (not shown), a monitor 302 for displaying information to the operator, and a photographic optical system 303 for taking an image of the operator and surroundings. Here, the monitor 302 includes a transmissive liquid crystal display element that illuminates from the back with a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front,
It may be an RT display or the like. Although the photographing optical system 303 is built in the upper right of the monitor 302 in the drawing, the position is not limited to this, and may be anywhere around the monitor 302 or around the keyboard 301.

This photographing optical system 303 includes a photographing optical path 304
Above, a variable power objective optical system 10 comprising the imaging optical system of the present invention.
0 and an image sensor chip 162 for receiving an image. These are built in the personal computer 300.

Here, an IR cut filter 180 is additionally attached on the image pickup device chip 162 to be integrally formed as an image pickup unit 160, and the rear end of the lens frame 101 of the variable magnification objective optical system 100 is touched with one touch. The variable-magnification objective optical system 100
There is no need to adjust the center of the image sensor chip 162 or adjust the surface distance, and the assembly is simplified. In addition, mirror frame 10
A cover glass 102 for protecting the variable-power objective optical system 100 is disposed at one end. The mirror frame 10
The drive mechanism of the variable magnification objective optical system 100 in FIG.

The object image received by the image sensor chip 162 is input to the processing means of the personal computer 300 via the terminal 166, and is displayed on the monitor 302 as an electronic image. The photographed image 305 of the person is shown. Also, this image 305
It can be displayed on a personal computer of a communication partner from a remote place via the processing means, the Internet or a telephone.

Next, a telephone, as another example of the information processing apparatus,
In particular, FIG. 25 shows an example in which the imaging optical system of the present invention is incorporated in a portable telephone which is particularly portable.

FIG. 25A is a front view of a mobile phone 400,
FIG. 25B is a side view, and FIG. 25C is a photographing optical system 40.
5 is a sectional view of FIG. As shown in FIGS. 25A to 25C, the mobile phone 400 includes a microphone unit 401 for inputting the voice of the operator as information, a speaker unit 402 for outputting the voice of the other party, and Input dial 4 for inputting
03, a monitor 404 for displaying information such as a photographed image of the operator himself or the other party and a telephone number, and a photographing optical system 405.
And an antenna 406 for transmitting and receiving communication radio waves, and processing means (not shown) for processing image information, communication information, input signals, and the like. Here, the monitor 404
Is a liquid crystal display element. In addition, in the drawings, the arrangement position of each component is not particularly limited to these. This photographing optical system 405
Has a variable-magnification objective optical system 100 composed of the imaging optical system of the present invention disposed on the photographing optical path 407, and an image sensor chip 162 for receiving an image. These are mobile phones 4
00.

Here, an IR cut filter 180 is additionally attached on the image pickup element chip 162 to be integrally formed as an image pickup unit 160, and the objective lens 12
Can be fitted and attached to the rear end of the lens frame 13 with one touch, so that the centering of the objective lens 12 and the imaging element chip 162 and the adjustment of the surface interval are not required, and the assembly is simplified. Also, at the tip of the lens frame 101,
Cover glass 1 for protecting variable magnification objective optical system 100
02 is arranged. The drive mechanism of the variable magnification optical system 100 in the lens frame 101 is not shown.

The object image received by the imaging element chip 162 is input to processing means (not shown) via a terminal 166, and is sent as an electronic image to the monitor 404, or to a monitor of a communication partner, or to both. Is displayed. When transmitting an image to a communication partner, the processing means includes a signal processing function of converting information of an object image received by the image sensor chip 162 into a signal that can be transmitted.

Next, FIGS. 26 and 27 show an information reproducing system using the imaging optical system of the present invention. A more detailed description is disclosed in JP-A-6-231466, and will not be repeated here. Here, in the multimedia information,
In particular, an embodiment related to audio information such as voice and music will be described. An audio information recording apparatus for recording audio information such as voice and music as an optically readable digital signal on paper is disclosed in Japanese Patent Application Laid-Open No. Hei 6-1994.
No. 231466.

With this apparatus, the image is recorded on the paper 130 in a format as shown in FIG. 26A, for example. That is, sound data digitized together with the image 132 and the character 134 is printed as the recording data 136. here,
The recording data 136 is composed of a plurality of blocks 138, and each block 138 is composed of a marker 138A, an error correction code 138B, audio data 138C, x address data 138D, y address data 138E, and an error determination code 138F. .

The marker 138A also functions as a synchronizing signal, and uses a pattern such as DAT which does not normally appear in recording modulation. The error correction code 138B is used for error correction of the audio data 138C. Audio data 138C
Corresponds to a microphone or audio signal. The x address data 138D and the y address data 138E are data indicating the position of the block 138, and the error determination code 138F is used for determining the error of the x address and the y address.

The recording data 13 in such a format
Reference numeral 6 denotes data of "1" and "0", which are printed and recorded by a printer system or a printing plate-making system, for example, like a bar code, such that "1" has a black dot and "0" has no black dot. . Hereinafter, such recording data is referred to as a dot code.

FIG. 26B shows a scene in which sound data recorded on the paper 130 as shown in FIG. 26A is read out by a pen-type information reproducing apparatus (information reproducing system) 140. I have. Such a pen-type information reproducing apparatus 140
By tracing over the dot code 136 with, the dot code 136 can be detected, converted to sound, and heard by the audio output device 142 such as an earphone.

FIG. 27 is a sectional view showing the internal structure of the pen-type information reproducing apparatus 140. As shown in FIG. The pen-type information reproducing device 140 includes a processing unit 503 having an electric circuit component 501 and a substrate 502 supporting the electric circuit component 501, a rear portion 500a having a battery cell 504, an imaging unit 160, and a light source 505 such as an LED. Front part 500b
Consists of The front part 500a and the rear part 500b
Are joined at a joint 506.

The pen-type information reproducing apparatus 140 has illumination light from a light source 505 (illustrated by arrows in the figure).
The variable magnification objective optical system 100 forms an object image on the image sensor chip 162 with the information recording medium 507 illuminated by the object as the object. Then, this image is converted into an electric signal and input to the processing means 503 electrically connected by the terminal 166 and the connection line 508. Then, as shown in FIG. 26, the operator can hear the sound through earphones or speakers.

Here, the pen-type information reproducing apparatus 140 allows the front part 500a and the rear part 500b to be separated from each other via the joint part 506 so that the photographing unit 160 can be easily incorporated and parts can be easily replaced. It is.

The information reproducing apparatus is not limited to the pen type, but may have various shapes.

Next, FIG. 30 shows a desirable configuration when the imaging optical system according to the present invention is arranged in front of an image pickup device such as a CCD or a filter. In the figure, an eccentric prism P is a prism member of the imaging optical system of the present invention. Now, when the imaging plane C of the imaging device forms a square as shown in the figure, the plane of symmetry F of the plane-symmetric free-form surface arranged on the eccentric prism P has at least one of the sides forming the square of the imaging plane C. Arrangement so as to be parallel to each other is desirable for beautiful image formation.

Further, when the imaging surface C has four interior angles, such as a square and a rectangle, each formed at approximately 90 °, the plane of symmetry F of the plane-symmetric free-form surface is parallel to the imaging surface C. It is arranged in parallel with certain two sides, more desirably, arranged in the middle of these two sides, and the configuration is such that the symmetry plane F coincides with the position where the imaging plane C is symmetrical left and right or up and down. preferable. With this configuration, it is easy to obtain the accuracy of assembling into the device,
It is effective for mass production.

Further, among the first transmitting surface, the first reflecting surface, the second reflecting surface, the third reflecting surface, and the second transmitting surface which are the optical surfaces constituting the decentered prism P, a plurality of or all the surfaces are provided. In the case of a plane-symmetric free-form surface, it is desirable from the viewpoint of design and aberration performance to configure such that a plurality of surfaces or symmetry surfaces of all surfaces are arranged on the same surface F. It is desirable that the relationship between the symmetry plane F and the imaging plane C be the same as described above.

The above-described imaging optical system of the present invention can be constituted, for example, as follows.

[1] In an imaging optical system having an overall positive refractive power for forming an object image, the imaging optical system is formed of a medium having a refractive index (n) larger than 1 (n> 1). A prism member, and the prism member emits the light beam out of the prism, a first transmission surface through which the light beam enters the prism, a first to a third reflection surface through which the light beam is reflected in the prism. It is composed of one bonded or integrally formed prism having a second transmitting surface, and is composed of an axial principal ray incident on the second reflecting surface and an axial principal ray reflected from the second reflecting surface. When projecting the axial principal ray on a defined plane, the second reflecting surface and the third reflecting surface fold the orbit of the axial principal ray in the prism into a triangular shape, and the second reflecting surface An incident axial principal ray and an axial principal ray emitted from the third reflecting surface And at least one of the first to third reflecting surfaces has a curved shape that gives power to a light beam, and the curved shape is an aberration generated by eccentricity. An imaging optical system characterized in that the imaging optical system is configured to have a rotationally asymmetric surface shape that corrects the image.

[2] In the above item 1, the cross optical path formed by the second reflection surface and the third reflection surface is an axial principal ray incident on the third reflection surface and reflected from the third reflection surface. A plane defined by the on-axis principal ray to be incident coincides with a plane defined by the on-axis principal ray incident on the second reflecting surface and the on-axis principal ray reflected from the second reflecting surface. An imaging optical system characterized by being configured to intersect.

[3] In the above item 1 or 2, the prism member is arranged in order from the object side, with a first transmitting surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, and a second transmitting surface. An image forming optical system is configured to form an optical path in the following order.

[4] In the above item 1 or 2, the prism member may include, in order from the object side, a first transmitting surface, a second reflecting surface, a third reflecting surface, a first reflecting surface, and a second transmitting surface. An image forming optical system is configured to form an optical path in the following order.

[5] In the above item 3, the prism member is provided with the second reflection surface so that the light beam reflected by the second reflection surface is directed to the object side, and the image forming surface is formed of the prism member. An imaging optical system characterized by being formed on a side opposite to an object side with a member interposed therebetween.

[6] In the above item 3, the prism member is provided with the second reflection surface so that the light beam reflected by the second reflection surface is directed in a direction opposite to the object side. An imaging optical system, wherein a surface is formed on an object side of the prism member.

[7] In the above item [4], the prism member is provided with the first reflection surface such that a light beam reflected by the first reflection surface is directed in a direction opposite to the object side. An imaging optical system, wherein a surface is formed on a side opposite to an object side with respect to the prism member.

[8] In the above item [4], the prism member is provided with the first reflection surface such that the light beam reflected by the first reflection surface is directed to the object side, and the image forming surface is formed of the prism. An imaging optical system characterized by being formed on the object side of a member.

[0225]

[9] In the above item 3 or 4, the prism member has a rotation direction of a light beam along a triangular optical path formed by the second reflection surface and the third reflection surface;
An image forming optical system, wherein a rotation direction of a light beam along an optical path incident on and reflected by the first reflection surface is in the same direction.

[10] In the above-mentioned item 3 or 4, the prism member is provided with a rotation direction of a light beam along a triangular optical path formed by the second reflection surface and the third reflection surface, and the first reflection surface. An imaging optical system characterized in that a rotation direction of a light beam along an optical path which is incident on and reflected from the optical axis is opposite to the rotation direction.

[11] The imaging method according to any one of the above items 1 to 10, wherein the prism member is configured such that the first reflection surface and the second transmission surface are the same surface. Optical system.

[12] In the above item 11, the prism member is characterized in that the first reflection surface is formed by a total reflection surface, so that the same surface is formed by a surface having both a reflection function and a transmission function. Imaging optics.

[13] In any one of the above-mentioned items 1 to 12, both the second reflecting surface and the third reflecting surface are rotationally asymmetric surfaces for applying power to a light beam and correcting aberrations caused by eccentricity. An imaging optical system, which is configured to have a shape.

[14] In any one of the above items 1 to 12, both the first reflecting surface and the second reflecting surface are rotationally asymmetric surfaces for applying power to a light beam and correcting aberrations caused by eccentricity. An imaging optical system, which is configured to have a shape.

[15] In any one of the above-mentioned items 1 to 12, both the first reflecting surface and the third reflecting surface are rotationally asymmetric surfaces for applying power to a light beam and correcting aberrations caused by eccentricity. An imaging optical system, which is configured to have a shape.

[16] In any one of the aforementioned items 1 to 15, the first transmitting surface is configured to have a rotationally asymmetric surface shape for applying power to a light beam and correcting aberration generated by eccentricity. An imaging optical system characterized in that:

[17] In any one of the above items 1 to 16, the second transmitting surface is configured to have a rotationally asymmetric surface shape for applying power to a light beam and correcting aberration generated by eccentricity. An imaging optical system characterized in that:

[18] The imaging optical system according to any one of the above items 1 to 16, wherein the second transmission surface is a flat surface.

[19] The imaging device according to any one of the above items 1 to 18, wherein an entrance pupil of the imaging optical system is formed between the prism member and the object. Image optics.

[20] In any one of the above items 1 to 19, the rotationally asymmetric surface shape may be such that only one symmetrical surface is one.
An imaging optical system characterized by having a plane-symmetric free-form surface shape having only surfaces.

[21] The imaging optical system according to any one of the above items 1 to 20, wherein the second reflecting surface satisfies the following conditional expression (1).

5 ° <θ ₁ <50 ° (1) where θ ₁ is the angle of incidence of the axial principal ray on the second reflecting surface.

[22] The imaging optical system according to any one of the above items 1 to 20, wherein the third reflecting surface satisfies the following conditional expression (2).

5 ° <θ ₂ <50 ° (2) where θ ₂ is the angle of incidence of the axial principal ray on the third reflecting surface.

[23] In any one of the above items 1 to 20, the second reflecting surface and the third reflecting surface satisfy the following conditional expressions (1) and (2). system.

5 ° <θ ₁ <50 ° (1) 5 ° <θ ₂ <50 ° (2) where θ ₁ is the incident angle of the axial principal ray to the second reflecting surface, θ
₂ is the angle of incidence of the axial principal ray on the second reflecting surface.

[24] The imaging optical system according to any one of the above items 1 to 23, wherein the first reflecting surface satisfies the following conditional expression (3).

30 ° <θ ₃ <60 ° (3) where θ ₃ is the angle of incidence of the axial principal ray on the first reflecting surface.

[25] In any one of the above items 1 to 24, a plane defined by an axial principal ray incident on the second reflecting surface and an axial principal ray reflected from the second reflecting surface may be used. When an on-axis principal ray is projected and the angle between the on-axis principal ray incident on the second reflecting surface and the on-axis principal ray emitted from the third reflecting surface is θ ₄ , the following conditional expression is used. (4)
An imaging optical system characterized by satisfying the following.

70 ° <θ ₄ <95 ° (4).

[26] In any one of the above items 1 to 25, the eccentric direction of the entire optical system is the Y-axis direction, and a plane parallel to the axial principal ray is a YZ plane. Assuming that the orthogonal direction is the X direction, the powers of the second and third reflecting surfaces in the X and Y directions are Psx and Psy, respectively.
When the powers in the X and Y directions of the entire prism are Px and Py, respectively, at least one of the second reflection surface and the third reflection surface satisfies the following conditional expression. Optical system.

0.001 <Psx / Px <100 (5).

[27] In any one of the above items 1 to 26, the eccentric direction of the entire optical system is the Y-axis direction, and a plane parallel to the axial principal ray is a YZ plane. Assuming that the orthogonal direction is the X direction, the powers of the second and third reflecting surfaces in the X and Y directions are Psx and Psy, respectively.
When the powers in the X and Y directions of the entire prism are Px and Py, respectively, at least one of the second reflection surface and the third reflection surface satisfies the following conditional expression. Optical system.

0.001 <Psy / Py <100 (6).

[28] In any one of the above items 1 to 26, the eccentric direction of the entire optical system is the Y-axis direction, a plane parallel to the axial principal ray is a YZ plane, and the YZ plane is When the orthogonal direction is defined as the X direction, the powers of the second reflecting surface and the third reflecting surface in the X direction and the Y direction are P2x and P3, respectively.
x, P2y, and P3y, and the powers of the entire prism in the X and Y directions are Px and Py, respectively.
The reflecting optical surface and the third reflecting surface satisfy the following conditional expression.

0.001 <P2x / Px <100 (7) 0.001 <P3x / Px <100 (8)

[29] In any one of the above items 1 to 27, the eccentric direction of the entire optical system is the Y-axis direction, and a plane parallel to the axial principal ray is a YZ plane. When the orthogonal direction is defined as the X direction, the powers of the second reflecting surface and the third reflecting surface in the X direction and the Y direction are P2x and P3, respectively.
x, P2y, and P3y, and the powers of the entire prism in the X and Y directions are Px and Py, respectively.
The reflecting optical surface and the third reflecting surface satisfy the following conditional expression.

0.001 <P2y / Py <100 (9) 0.001 <P3y / Py <100 (10)

[30] The imaging optical system according to any one of the above items 1 to 29, further comprising an imaging element for receiving an object image arranged on the image plane.

[31] In any one of the above items 1 to 29, a brightness stop is arranged at an entrance pupil position of the imaging optical system, and an image pickup device is arranged on the image plane. Imaging optics.

[32] A processing member comprising the imaging optical system according to the above item 30 or 31, wherein the image pickup device comprises an electronic image pickup device for photoelectrically converting object light into an electronic signal, and a processing member for processing the electronic signal; A display device for displaying object image information digitized from the processing member.

[33] An electronic imaging system comprising the imaging optical system according to the above item 30 or 31, wherein the object displays information as a barcode or a dot, and the image pickup device photoelectrically converts the object light into an electronic signal. A processing member that is configured by an element and performs a process of recognizing barcode or dot information as an audio signal from the electronic signal, and a sound generation member that externally represents the recognized audio signal from the processing member as a sound. An information reproducing apparatus characterized in that:

[34] An information input device comprising the image forming optical system according to the above item 30 or 31, wherein the image pickup device comprises an electronic image pickup device for photoelectrically converting object light into an electronic signal, and inputs information such as a telephone number. A mobile phone device comprising: a unit; an antenna unit for transmitting and receiving signals; a processing member for processing the electronic signal; and a display element for displaying object image information digitized from the processing member.

[35] An information input unit comprising the imaging optical system according to the above item 30 or 31, wherein the image pickup device is constituted by an electronic image pickup device for photoelectrically converting object light into an electronic signal, and an operator inputs information. An information processing apparatus comprising: a processing member that processes the electronic signal; and a display element that displays object image information digitized from the processing member.

[36] The imaging optical system according to any one of the above 1 to 29 is arranged as a finder objective optical system, and further, an image corrector for erecting an object image formed by the finder objective optical system. A finder optical system comprising a vertical optical system and an eyepiece optical system.

[37] A camera device comprising: the finder optical system according to the above-mentioned 36; and a photographing objective optical system provided in parallel with the finder optical system.

[38] The imaging optical system according to any one of the above 1 to 29 is disposed as a photographing objective optical system, and an optical path different from the photographing optical system or the photographing objective optical system. And a finder optical system disposed in any one of the optical paths divided from the optical path.

[39] An observation system comprising the imaging optical system according to any one of the above items 1 to 29, and an image transmission member for transmitting an image formed by the imaging optical system along a long axis direction. An endoscope apparatus comprising: an illumination light source; and an illumination system having an illumination light transmission member that transmits illumination light from the illumination light source along the long axis direction.

[0265]

As is apparent from the above description, according to the present invention, by appropriately using a rotationally asymmetric surface,
It is possible to provide an imaging optical system including a compact and high-performance prism optical system in which aberrations generated due to eccentricity are satisfactorily corrected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an imaging optical system according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an imaging optical system according to a sixth embodiment of the present invention.

FIG. 3 is a sectional view of an imaging optical system according to Example 11 of the present invention.

FIG. 4 is a sectional view of an imaging optical system according to Example 12 of the present invention.

FIG. 5 is a sectional view of an imaging optical system according to Example 13 of the present invention.

FIG. 6 is a YZ sectional view of an imaging optical system according to Example 14 of the present invention.

FIG. 7 is an XY cross-sectional view of an imaging optical system according to Example 14 of the present invention.

FIG. 8 is an XZ sectional view of an imaging optical system according to Example 14 of the present invention.

FIG. 9 is a sectional view of an imaging optical system according to Example 15 of the present invention.

FIG. 10 is a sectional view of an imaging optical system according to Example 16 of the present invention.

FIG. 11 is a sectional view of an imaging optical system according to Example 17 of the present invention.

FIG. 12 is a sectional view of an imaging optical system according to Example 18 of the present invention.

FIG. 13 is a lateral aberration diagram of the image forming optical system according to the second embodiment.

FIG. 14 is a lateral aberration diagram of the imaging optical system of Example 7;

FIG. 15 is a lateral aberration diagram of the imaging optical system of Example 15;

FIG. 16 is a front perspective view showing the appearance of an electronic camera to which the imaging optical system of the present invention is applied.

FIG. 17 is a rear perspective view of the electronic camera of FIG. 16;

18 is a cross-sectional view illustrating a configuration of the electronic camera in FIG.

FIG. 19 is a conceptual diagram of another electronic camera to which the imaging optical system of the present invention is applied.

FIG. 20 is a conceptual diagram of an electronic endoscope to which the imaging optical system of the present invention is applied.

FIG. 21 is a conceptual diagram of a configuration using a prism optical system according to the present invention as a projection optical system of a presentation system.

FIG. 22 is a front perspective view of a personal computer in which the imaging optical system of the present invention is incorporated as an objective optical system with a cover opened.

FIG. 23 is a sectional view of a photographing optical system of a personal computer.

FIG. 24 is a side view of the state of FIG. 23;

FIG. 25 is a front view, a side view, and a sectional view of a photographing optical system of a mobile phone in which the image forming optical system of the present invention is incorporated as an objective optical system.

FIG. 26 is a diagram illustrating a form of information reproduced by an information reproducing system to which the imaging optical system according to the present invention is applied.

FIG. 27 is a cross-sectional view showing the internal configuration of a pen-type information reproducing apparatus using the imaging optical system of the present invention.

FIG. 28 is a diagram in which possible arrangements of each optical surface of the imaging optical system of the present invention are classified.

FIG. 29 is a diagram for explaining the definition of the power of the decentered optical system and the optical surface.

FIG. 30 is a diagram showing a desirable configuration when an imaging optical system according to the present invention is arranged in front of an image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... On-axis principal ray 2 ... Stop (entrance pupil) 3 ... Image surface 10 ... Prism 11 ... 1st reflection surface 12 ... 2nd reflection surface 13 ... 3rd reflection surface 14 ... 1st transmission surface 15 ... 2nd transmission surface Reference Signs List 40 ... Electronic camera 41 ... Shooting optical system 42 ... Shooting optical path 43 ... Finder optical system 44 ... Finder optical path 45 ... Shutter 46 ... Flash 47 ... Liquid crystal display monitor 48 ... Shooting objective optical system 49 ... CCD 50 ... Imaging surface 51 ... Filter 52 ... Processing means 53 ... Finder objective optical system 54 ... Cover lens 55 ... Porro prism 56 ... First reflection surface 57 ... Field frame 58 ... Second reflection surface 59 ... Eyepiece optical system 60 ... Liquid crystal display device (LCD) DESCRIPTION OF SYMBOLS 61 ... Recording means 62 ... Incident surface 63 ... Reflective surface 64 ... Combined surface of reflection and refraction 65 ... Cover member 66 ... Focusing lens 67 ... Imaging surface 71 ... Electronic endoscope Mirror 72 ... Light source device 73 ... Video processor 74 ... Monitor 75 ... VTR deck 76 ... Video disc 77 ... Video printer 78 ... Head mounted image display device (HMD) 79 ... Insertion section 80 ... Tip section 81 ... Eyepiece section 82 ... Observation objective optical system 83 ... Filter 84 ... CCD 85 ... Cover member 86 ... Liquid crystal display device (LCD) 87 ... Eyepiece optical system 88 ... Light guide fiber bundle 89 ... Illumination objective optical system 90 ... PC 91 ... Liquid crystal projector 92 ... Light source 93 ... Liquid crystal panel (LCP) 94 ... Cover lens 95 ... Field lens 96 ... Projection optical system 97 ... Screen 98 ... Process control unit 100 ... Objective optical system 101 ... Mirror frame 102 ... Cover glass 130 ... Paper 132 ... Image 134 ... Character 136 ... Recording data (dot code) 138 ... Block 1 8A: marker 138B: error correction code 138C: audio data 138D: x address data 138E: y address data 138F: error determination code 140: pen type information reproducing device (information reproducing system) 142: audio output device 160: imaging unit 162 ... Imaging element chip 166 ... Terminal 180 ... IR cut filter 300 ... PC 301 ... Keyboard 302 ... Monitor 303 ... Shooting optical system 304 ... Shooting optical path 305 ... Image 400 ... Mobile phone 401 ... Microphone section 402 ... Speaker section 403 ... Input dial 404 ... Monitor 405... Photographing optical system 406... Antenna 407... Photographing optical path 500 a. 507 ... information recording medium 508 ... connecting line S ... decentered optical system E ... observer's eyeball P ... plane of symmetry of the decentered prism C ... imaging plane F ... plane-symmetry free-form surface

Claims (3)

[Claims] 1. An imaging optical system having an overall positive refractive power for forming an object image, wherein the imaging optical system has a refractive index (n) greater than 1 (n
> 1) a prism member formed of a medium, wherein the prism member is configured to firstly enter a light beam into the prism;
A single prism that is joined or integrally formed, having a transmission surface, first to third reflection surfaces that reflect a light beam inside the prism, and a second transmission surface that emits the light beam outside the prism; When projecting the axial principal ray on a plane defined by the axial principal ray incident on the second reflecting surface and the axial principal ray reflected from the second reflecting surface, the second reflecting surface and the second reflecting surface The third reflecting surface folds the trajectory of the axial chief ray in the prism into a triangular shape, and is formed by the axial chief ray incident on the second reflecting face and the axial chief ray emitted from the third reflecting face. At least one of the first to third reflecting surfaces has a curved surface shape that gives power to a light beam, and the curved surface shape corrects aberration caused by eccentricity. Is configured to have a rotationally asymmetric surface shape An imaging optical system, characterized in that there. 2. The method according to claim 1, wherein the prism member includes, in order from an object side, a first transmission surface;
An imaging optical system, wherein an optical path is formed in the order of a first reflecting surface, a second reflecting surface, a third reflecting surface, and a second transmitting surface. 3. The method according to claim 1, wherein the prism member includes, in order from an object side, a first transmission surface;
An imaging optical system characterized in that an optical path is formed in the order of a second reflecting surface, a third reflecting surface, a first reflecting surface, and a second transmitting surface.