JP4047886B2 - Electronic imaging apparatus having mirror scan function - Google Patents

Description

  The present invention relates to an electronic imaging apparatus having a mirror scan function for a high-definition electronic video input device.

  Electronic images can be processed in a wide variety of ways, and in recent years, they are increasingly used not only as photographs but also as computer input information. However, an electronic image obtained by a conventional electronic image pickup apparatus has a very small number of pixels of the image pickup device as compared with a silver halide photograph, and thus cannot capture characters, fine patterns, and the like. For this reason, it is conceivable to use an HDTV-standard imaging device, but the imaging area increases, and the optical system becomes large accordingly, but the number of pixels is still insufficient. Also, with a scanner using a line sensor, the capturing speed is very slow, and it is difficult to photograph a three-dimensional object.

  In view of the above-described problems of the prior art, the present invention provides conventional NTSC, PAL, and HDTV standard imaging devices in order to obtain a compact and inexpensive high-definition electronic video input device comparable to a conventional still video camera. It is an object of the present invention to provide an electronic imaging device having a mirror scan function that can substantially equal the number of pixels to the HDTV standard or higher, and can use a silver salt level.

In order to achieve the above object, an electronic imaging apparatus having a mirror scan function according to the present invention includes, in order from the object side , a first lens group having a negative refractive power composed of a single negative lens and light from an object point. A second lens group having a positive refracting power including a rotatable mirror and a positive lens for bending the axis, and a third lens group having a positive refracting power capable of moving partly or entirely on the optical axis. And an electronic imaging device that receives light that has passed through the imaging optical system are arranged to satisfy the following conditional expressions at the same time.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <3 (7)
However, d is the distance between the pupil position of the imaging optical system as viewed from the position as the center position of rotation of the rotatable mirror, n ₁ is the refractive index of the positive lens disposed on the most object side, n ₂ represents the refractive index of the negative lens disposed closest to the object side, and r ₁ and r ₂ represent the radius of curvature of the positive lens disposed closest to the object side and the radius of curvature on the image side, respectively.
Moreover, it is preferable that the electronic imaging apparatus having a mirror scan function according to the present invention satisfies the following conditional expression instead of the conditional expression (1).
10 mm <d <20 mm (8)
Moreover, it is preferable that the electronic imaging apparatus having a mirror scan function according to the present invention satisfies the following conditional expression instead of the conditional expression (2).
0.2 <n ₁ −n ₂ <0.4 (9)
Moreover, it is preferable that the electronic imaging apparatus having a mirror scan function according to the present invention satisfies the following conditional expression instead of the conditional expression (7).
1.2 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <2 (10)

In order to achieve the above object, an electronic imaging apparatus having a mirror scanning function according to the present invention includes a rotatable mirror for bending an optical axis from an object point and two or less negative lenses in order from the object side. A first lens group composed of a single positive lens and having a negative refractive power as a whole, and an aperture stop and a second lens group having a positive refractive power that can move partially or entirely on the optical axis. An image optical system and an electronic imaging device that receives light that has passed through the imaging optical system are arranged and configured to satisfy the following conditional expressions at the same time.
7mm <d <25mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
−1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (11)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ is the refractive index of the positive lens located closest to the object side, n ₂ represents the refractive index of the negative lens disposed closest to the object side, and r ₁ and r ₂ represent the radius of curvature of the positive lens disposed closest to the object side and the radius of curvature on the image side, respectively.
Moreover, it is preferable that the electronic imaging device having the mirror scan function of the present invention satisfies the following conditional expression instead of the conditional expression (1).
15mm <d <23mm (12)
Moreover, it is preferable that the electronic imaging apparatus having a mirror scan function according to the present invention satisfies the following conditional expression instead of the conditional expression (2).
0.15 <n ₁ −n ₂ <0.4 (5)
Moreover, it is preferable that the electronic imaging device having a mirror scan function according to the present invention satisfies the following conditional expression instead of the conditional expression (11).
0 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (13)

Furthermore, in the electronic imaging apparatus having a mirror scanning function according to the present invention, a semi-transparent mirror that divides light into a direction in which an optical axis is bent and a through direction is arranged between the imaging optical system and the electronic imaging device. It is preferable.
In this case, it is preferable that an optical low-pass filter using crystal birefringence is disposed between the imaging optical system and the half mirror.
Further, in that case, the azimuth angle of the orthogonal projection image on the imaging plane by the imaging optical system of the crystal axis of the filter arranged closest to the semi-transparent mirror among the optical low-pass filters is the rotation angle. It is preferable that the angle is 40 to 50 degrees with respect to the possible rotation axis of the mirror.

  According to the present invention, while using a conventional CCD with a low number of pixels and a small effective imaging area, and an inexpensive and small optical system that has a performance and size corresponding to the conventional CCD, the actual number of pixels is small. High-definition images comparable to silver salt can be easily obtained with HDTV standards or higher. As a result, it is possible to easily capture fine characters, patterns, and the like that are impossible with a conventional simple electronic imaging apparatus, and to realize an image input device of an information processing system with good operability. In the apparatus having such a mirror scanning function, the parallax during scanning that occurs when the conventional imaging optical system is used can be eliminated by using the electronic imaging apparatus having the mirror scanning function of the present invention.

  The electronic imaging apparatus having a mirror scan function according to the present invention incorporates a two-dimensional device having a small imaging area, an imaging optical system suitable for performance, and a rotating mirror. The image pickup system is used to divide an object (subject) with a large prospective angle into several regions, and correspondingly capture each image as a plurality of images while rotating the rotating mirror. One image is formed by stitching together.

That is, FIG. 1 is a conceptual diagram showing the configuration of an electronic imaging apparatus having a mirror scanning function according to the present invention. The electronic imaging apparatus having a mirror scanning function according to the present invention has negative refractive power in order from the object side (not shown). A first lens group (not shown) including a negative lens closest to the object side, a rotating mirror 1 for bending the optical axis L _C from the object point, an aperture stop 2 and a part of the optical axis L _C The optical path is divided into an imaging optical system including a second lens group 3 having a positive refractive power that can be moved as a whole, an optical low-pass filter 4 using the birefringence of crystal, and a bending direction and a through direction. The semi-transparent mirror 5 and electronic imaging devices 6 and 7 arranged at conjugate positions on the optical path divided by the semi-transparent mirror 5 are arranged.
FIG. 1 is a diagram for explaining the concept, and the traveling direction of the incident light to the rotating mirror 1 is different from the actual one due to the limitation of the illustration.

Therefore, the electronic image pickup apparatus having a mirror scan function according to the present invention can use an inexpensive image pickup device, and can further reduce a necessary image circle, thereby realizing a small image forming optical system. However, the electronic imaging apparatus having the mirror scan function according to the present invention has a large problem as shown in the following (1) to (3) in connecting images.
(1) Since the shooting tilt angle differs for each divided image, figure distortion occurs after the images are joined. Even if the object to be photographed is a plane, the object distance is slightly shifted with the rotation of the mirror, and the entire screen cannot be focused uniformly.
(2) When distortion occurs due to the imaging optical system, it becomes impossible to join images.
(3) When parallax occurs in adjacent portions of adjacent images, the images cannot be joined.

  However, the above distortion problems (1) and (2) can be corrected by digitizing the image signal and performing processing such as coordinate transformation. After the correction processing, the images are joined together. The above problem can be solved by performing. Further, out of focus shift due to tilt, the focus shift on the entire screen can be dealt with by setting the specification so that it is within the depth of focus because the shift is very small. Regarding the problem of the subject distance shifting with the rotation of the mirror, focus adjustment may be performed for each rotation of the mirror. At this time, the size of the image changes due to focusing, and similarly correction by changing the specification setting is required. In this case, since the amount of focus adjustment is very small, if the image side principal ray is substantially parallel to the optical axis, correction is virtually unnecessary.

Regarding the parallax problem (3), unlike the problems (1) and (2), electrical correction is impossible, so this must be resolved with first priority. The reason why the parallax occurs is that the center of rotation of the mirror is away from the entrance pupil of the imaging optical system. Therefore, as long as a normal lens system is used as the imaging optical system, this problem cannot be solved.
Therefore, in the present invention, in order to scan the object to be photographed, as shown in FIG. 1, following the rotating mirror for bending the optical axis from the object point, the front aperture optical system, that is, the imaging optical system The entire optical system is configured so that an optical system having an aperture stop on the object side of the system can be arranged so that the rotation center of the mirror and the entrance pupil of the optical system are as close as possible. As a result, the parallax can be corrected to a level that has no practical effect.

  On the other hand, various optical elements such as various filters are often inserted between the imaging optical system and the electronic imaging device, and the size of the effective imaging surface of the electronic imaging device has gradually decreased in recent years. Therefore, the imaging optical system is required to have a large back focus length to focal length ratio. Therefore, in the present invention, how to arrange the aperture stop and the rotating mirror with respect to the so-called retrofocus type lens is a structural point.

As a first method, two lenses of a negative lens and a positive lens (as a first lens group having negative refractive power and including a negative lens closest to the object side and including a positive lens) in order from the object side A first lens unit having negative refractive power as a whole, a rotatable mirror for bending the optical axis from the object point for scanning the object, an aperture stop, and a part on the optical axis Alternatively, the electronic imaging apparatus adopts a retrofocus imaging optical system having a mirror scan function in which a second lens group having a positive refractive power that is movable as a whole is disposed. With a retrofocus type lens, it is extremely difficult to use a front aperture. Therefore, in the normal retrofocus type, the distance between the first lens group having negative refractive power and the second lens group having positive refractive power is large. A rotating mirror and an aperture stop are provided here, taking advantage of the fact that it is wide. In the electronic imaging apparatus having the mirror scan function configured as described above, the following conditional expressions are satisfied simultaneously.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
2 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <10 (3)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from the position, n ₁ is the refractive index of the positive lens located closest to the object side, and n ₂ Denotes the refractive index of the negative lens arranged closest to the object side, and r ₁ and r ₂ denote the curvature radii of the object side and image side of the positive lens arranged closest to the object side, respectively (the same applies hereinafter). .

Furthermore, it is more preferable that any one of the above values d, n ₁ −n ₂ , or (r ₁ + r ₂ ) / (r ₁ −r ₂ ) satisfies the following conditions.
12mm <d <23mm (4)
0.15 <n ₁ −n ₂ <0.4 (5)
3 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <8 (6)

The conditional expression (1) defines the distance between the center position of rotation of the rotating mirror and the pupil image position of the imaging optical system viewed from that position. The value of d is the conditional expression (1). If the value falls below the lower limit of the range of values that can be taken, there is insufficient space for the rotating mirror to rotate, making mirror scanning impossible. On the other hand, when the value of d exceeds the upper limit, the mutual parallax of individual images that are combined to form an image cannot be allowed.
Conditional expression (2) defines the difference in refractive index between the positive lens and the negative lens arranged closest to the object side, and the mirror scan function of the present invention is likely to generate a large positive Petzval sum. In an electronic imaging device having the above, it is preferable to set the value of n ₁ −n ₂ to be large. If the value of n ₁ −n ₂ is below the lower limit of the range of values that can be taken by conditional expression (2), a large Petzval sum tends to occur, which is inappropriate. On the other hand, the upper limit value of n ₁ -n ₂ may be the maximum value specific to the lens material constituting the electronic imaging apparatus having the mirror scan function of the present invention.
Conditional expression (3) defines the shape factor of the positive lens arranged closest to the object side, and the value of (r ₁ + r ₂ ) / (r ₁ −r ₂ ) is the value of conditional expression (3). If the lower limit of the range of possible values is not reached, it becomes difficult to correct distortion. On the other hand, when the value of (r ₁ + r ₂ ) / (r ₁ −r ₂ ) exceeds the upper limit, it is difficult to correct spherical aberration and coma aberration.

As a second method of the present invention, in order from the object side, a first lens group having a negative refractive power composed of a negative single lens, and an optical axis from an object point for scanning the object. A rotatable mirror for bending the lens, a second lens group having a positive single lens (as a second lens group including a positive lens and having a positive refractive power), an aperture stop, and a part on the optical axis Alternatively, the electronic imaging apparatus adopts a retrofocus imaging optical system having a mirror scan function in which a third lens group having a positive refractive power that is movable as a whole is arranged. Thereby, the full length and front lens diameter of an optical system can be made smaller than a 1st system. In the electronic imaging apparatus having the mirror scan function configured as described above, the following conditional expressions are satisfied at the same time.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <3 (7)
Furthermore, it is more preferable that any one of the above values d, n ₁ −n ₂ , or (r ₁ + r ₂ ) / (r ₁ −r ₂ ) satisfies the following conditions.
10 mm <d <20 mm (8)
0.2 <n ₁ −n ₂ <0.4 (9)
1.2 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <2 (10)
The reasons for defining conditional expressions (1) and (2) are as described above, and the reason for defining conditional expression (7) is the same as in conditional expression (3).

The third method consists of, in order from the object side, a rotatable mirror for bending the optical axis from the object point to scan the object, two or less negative lenses, and one positive lens. A mirror scanning function in which a first lens group having a negative refractive power as a whole, an aperture stop, and a second lens group having a positive refractive power that is partially or entirely movable on the optical axis are arranged. An electronic imaging device employing a retrofocus imaging optical system having Thereby, the total length and front lens diameter of the optical system can be further reduced as compared with the second method. In the electronic imaging apparatus having the mirror scan function configured as described above, the following conditional expressions are satisfied at the same time.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
−1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (11)
Furthermore, it is more preferable that any one of the above values d, n ₁ −n ₂ , or (r ₁ + r ₂ ) / (r ₁ −r ₂ ) satisfies the following conditions.
15 mm <d <23 mm (12)
0.15 <n ₁ −n ₂ <0.4 (5)
0 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (13)
The reasons for defining conditional expressions (1) and (2) are as described above, and the reason for defining conditional expression (11) is the same as in conditional expression (3).

In addition, the imaging optical system employed in the third method includes, in order from the object side, a rotatable mirror for bending the optical axis from the object point (with negative refractive power and most positive on the object side). A first lens group having a negative refractive power as a whole, a positive lens (as a first lens including a lens and a negative lens) and a negative meniscus lens having a convex surface facing the object side, an aperture stop, If the second lens group which is composed of a lens and three positive lenses and which is disposed on the most object side is movable on the optical axis and has a positive refractive power as a whole, a small lens can be formed. The imaging performance is the same as that shown in the third method, and the part having the function as the imaging optical system becomes simpler. In the electronic imaging apparatus having the mirror scan function configured as described above, the following conditional expressions are satisfied simultaneously.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
−3 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (14)
Furthermore, it is more preferable that any one of the above values d, n ₁ −n ₂ , or (r ₁ + r ₂ ) / (r ₁ −r ₂ ) satisfies the following conditions.
12 mm <d <20 mm (15)
0.2 <n ₁ −n ₂ <0.4 (9)
−1.5 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <− 0.6 (16)
The reasons for defining conditional expressions (1) and (2) are as described above, and the reason for defining conditional expression (14) is the same as in conditional expression (3).

  In the electronic imaging device having the mirror scan function as in the present invention, the conditional expression (1) defined in order not to generate parallax is a feature, and if only the mirror scan function is employed, Conditional expressions (2) and (3) that specify the secondary purpose of improving the perfection of aberration correction are not particularly necessary.

  Further, as described above, the electronic image pickup apparatus having a mirror scan function according to the present invention is configured to minimize the difference between the position of the rotary mirror and the pupil image position of the imaging optical system viewed from the position. ing. Therefore, the parallax can be suppressed to a level where there is no practical problem.

By the way, when the rotation direction of the rotating mirror is limited to one direction, a wide angle of view can be obtained only in that direction, but the angle of view with respect to the vertical direction remains narrow. Therefore, two electronic imaging devices (hereinafter referred to as CCDs) are disposed in the direction perpendicular to the rotation direction of the mirror. However, when the CCDs are arranged side by side on the same plane, effective images cannot be connected. Therefore, in the present invention, a semi-transparent mirror that divides the light is disposed between the imaging optical system and the imaging point, and at the conjugate positions on the respective optical axes divided by the two. A CCD is arranged, and the images obtained by the CCDs are joined together to secure a field angle in a direction parallel to the rotation axis direction of the rotating mirror so that the aspect ratio of the image can be balanced. is doing.
That is, as shown in FIG. 2A, even if two CCDs 6 and 7 are arranged side by side, the light receiving portions 7a and 7b cannot be in contact with each other. Therefore, the CCD 6 and CCD 7 are shown in FIG. In this way, the images are arranged at conjugate positions on the optical axis divided in two directions, and the images picked up by the CCDs 6 and 7 are combined so that the light receiving portions of the two CCDs 6 and 7 come into contact with each other Is set to a proper positional relationship. Therefore, as shown in FIG. 2B, a combined vertically long light receiving portion is formed.

  In addition, the effective imaging surface of the CCD is usually rectangular, but when one screen is formed with four or more shots (one shot means one shooting operation) through mirror scanning, the long side direction of one CCD is It is preferable to match with the direction parallel to the rotation direction of the rotary mirror that reduces the number of screen divisions. On the other hand, in the case of two shots, it is preferable to match the long side direction of the CCD with a direction substantially perpendicular to the rotation axis of the rotating mirror, from the viewpoint of efficiently using the image circle. In this case, it is more efficient that the direction of bending of the optical axis by the semi-transparent mirror is a direction parallel to a plane including the rotation direction of the mirror because the thickness of the semi-transparent mirror is reduced. In the case of 3 shots, there is almost no difference in efficiency.

  Next, as long as the CCD is used, a filter for preventing the aliasing distortion is necessary. Usually, the filter is inserted between the imaging optical system and the CCD. If the filter is inserted, only one set of filters is required. In this case, the polarizing action of the filter and the semi-transparent mirror affects the light splitting ratio of the semi-transparent mirror. Therefore, the azimuth angle of the orthogonal projection image of the crystal axis of the optical low-pass filter that is disposed closest to the semi-transparent mirror to the imaging plane by the imaging optical system is the rotational axis of the mirror. It is necessary to dispose the optical low-pass filter so that the angle is 40 to 50 degrees.

  The optical low-pass filter is made of a crystalline material. In the present invention, the light incident on the low-pass filter is separated into an ordinary ray and an extraordinary ray polarized perpendicularly to each other. On the other hand, the semi-transparent mirror also has a polarizing action. Therefore, in order to generate the same amount of P-polarized light and S-polarized light of the reflected light of the semi-transparent mirror, the ordinary ray and the extraordinary ray have an angle of 40 to 50 degrees with respect to the rotation axis of the rotating mirror. It is necessary to set so as to be emitted from the optical low-pass filter. By doing so, even if an optical element having a polarizing action such as the semi-transparent mirror is inserted into the optical path of the optical system of the present invention, it normally functions as an optical low-pass filter.

  The basic configuration of the present invention will be described below with reference to FIG.

  FIG. 3 is a lens configuration diagram of an optical system constituting an electronic imaging apparatus having a mirror scan function according to the present invention, where (a) is a cross-sectional view taken along the optical axis of the optical system, and (b) is viewed from above. (C) is a cross section perpendicular to the rotation axis of the rotary mirror as viewed from the side. FIG. FIG. 4 is a diagram for explaining an imaging state of the object image formed by the imaging optical system provided in the electronic imaging device having the mirror scanning function of the present invention with the CCD.

As shown in FIGS. 3A to 3C, the optical system provided in the electronic imaging apparatus having the mirror scan function of the present invention has negative refractive power in order from the object side (not shown) and has the most negative power on the object side. A first lens group (not shown) including a lens, a rotary mirror 1, an aperture stop 2, a second lens group 3, an optical low-pass filter 4 and a semi-transparent mirror 5 are arranged. , 7 are provided. The second lens group 3 includes, in order from the object side, a cemented negative lens 3a composed of a positive lens and a negative lens, a matching positive lens 3b composed of a negative lens and a positive lens, and a cemented positive lens 3c composed of a positive lens and a negative lens. it is constituted is arranged, some or all of these lenses are able to perform the focusing moves on the optical axis L _C. Further, when the limit of the perpendicularity of the incident light to the CCDs 6 and 7 is severe, or when the semi-transparent mirror 5 is inserted on the image side of the second lens group 3 and the optical path is divided, the exit pupil of the lens group is It is preferable that lenses 8 and 9 having positive refractive power are additionally inserted between the semi-transparent mirror 5 and the CCD 6 and between the semi-transparent mirror 5 and the CCD 7 so as to be telecentric as much as possible. As a result, the emitted light from the optical system provided in the electronic image pickup apparatus having the mirror scan function of the present invention not only enters the image pickup surface at a substantially right angle, but also suppresses the change in the image size due to focusing. be able to.

  In the electronic imaging apparatus having the mirror scan function of the present invention, as shown in FIG. 3B, the optical path is divided into the direction of the CCD 6 and the direction of the CCD 7 by the semi-transparent mirror 5. FIG. 4 shows an object image formed by the second lens group 3 of the imaging optical system. The upper part A of this object image passes through the semi-transparent mirror 5 and is picked up by the CCD 6. The part B is bent by the semi-transparent mirror 5 and imaged by the CCD 7. An arrow C in the figure indicates the direction of scanning by the rotating mirror 1.

  Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

First Embodiment FIG. 5 is a diagram showing a cross section perpendicular to the rotation axis of a rotating mirror of an optical system constituting an electronic imaging apparatus having a mirror scanning function according to this embodiment. In the electronic imaging apparatus having the mirror scan function of the present embodiment, first, in order from the object side (not shown) (as the first lens group having negative refractive power and including the negative lens closest to the object side and including the positive lens) A first lens group 11 comprising a negative meniscus lens 11a having a convex surface facing the object side and a positive meniscus lens 11b having a concave surface facing the object side and having negative refractive power as a whole, a rotating mirror 12, an aperture stop 13, and A negative lens and a positive lens, a negative lens 14a, a negative lens and a positive lens, a positive lens 14b, a positive lens 14c, and a positive lens and a negative lens 14d are positively refracted as a whole. An imaging optical system 21 is configured by arranging a second lens group 14 having force. Further, each lens constituting the second lens group 14, a part or entirety thereof is adapted to be moved along the optical axis L _C. Further, on the exit side of the second lens group 14, an infrared cut filter or λ / 4 plate 15, an optical low-pass filter 16 made of a birefringent plate such as a quartz plate, and a prism 17 made of a beam splitter including a semi-transmissive surface. Is arranged. CCDs 18 and 19 are provided in the emission direction of the prism 17, and a cover glass (or positive lens) 20 is disposed between the prism 17 and the CCD 18 (not shown, but not shown) A similar cover glass or positive lens is arranged between them).

The rotation axis of the rotary mirror 12 is in a direction perpendicular to the paper surface, and the extension line of the optical axis L _C of the second lens group 14 is at a position where it intersects the mirror surface. The optical low-pass filter 16 is formed by bonding one sheet or a plurality of filters having different crystal axis directions, and the crystal axis of the filter closest to the prism 17 forms approximately 45 degrees with respect to the plate surface. As shown in FIG. 6, the orthogonal projection of the crystal axis onto the plate surface is substantially 45 degrees with respect to the rotation axis of the rotating mirror 12, and the incident light is divided into ordinary rays and extraordinary rays on the CCDs 18 and 19, respectively. It has the function of forming a double image that is slightly displaced.

The electronic image pickup apparatus having a mirror scan function according to the present embodiment is configured to take an entire object image in two shots (two photographing operations), and the CCD 18 on which light passing through the prism 17 is incident has a light receiving surface. Are arranged so that their long sides are perpendicular to the rotary mirror 12, while the CCD 19 determines the orientation of the light receiving surface accordingly. Accordingly, FIG. 7 shows an object image formed by the imaging optical system 21, and the upper part A of this object image is taken by the CCD 18 through the prism 17, and the lower part B Is taken by the CCD 19 after being bent by the prism 17. An arrow C in the figure indicates the direction of scanning by the rotating mirror 12.
In this way, in the electronic imaging apparatus having the mirror scan function of this embodiment, the object image is reproduced by synthesizing the four screens.

In the electronic imaging apparatus having the mirror scan function of the present embodiment shown in FIG. 5, the rotating mirror 12 is at a position indicated by a broken line (position where the angle of the mirror surface with respect to the optical axis L _C is 45 degrees). In this state, the optical axis L _C can be bent below the 90-degree rotating mirror 12. Further, the position indicated by the solid line is a state in which the rotating mirror 12 is rotated to the maximum, and is a state in which the principal ray having the maximum image height is rotated by half the angle formed by the optical axis L _C. Of course, the rotating mirror 12 can also be rotated in a direction opposite to the illustrated direction.

Hereinafter, numerical data of optical elements such as lenses constituting the electronic imaging apparatus having the scanning function according to the present embodiment will be shown.
d = 15 mm, n ₁ −n ₂ = 0.20207
(R ₁ + r ₂ ) / (r ₁ −r ₂ ) = 6.375

r ₁ = 42.8695
d ₁ = 1.5000 n ₁ = 1.60311 ν ₁ = 60.70
r ₂ = 19.0755
d ₂ = 10.1431
r ₃ = -38.0797
d ₃ = 2.1000 n ₃ = 1.80518 ν ₃ = 25.43
r ₄ = -27.7527
d ₄ = 28.0000
r ₅ (aperture stop 13) = ∞
d ₅ = 4.5000

r ₆ = -10.5481
d ₆ = 0.9000 n ₆ = 1.60311 ν ₆ = 60.70
r ₇ = 7.5000
d ₇ = 3.0000 n ₇ = 1.59270 ν ₇ = 35.30
r ₈ = 275.3552
d ₈ = 0.7533
r ₉ = -124.5995
d ₉ = 1.0000 n ₉ = 1.84666 ν ₉ = 23.78
r ₁₀ = 33.1292
d ₁₀ = 3.1000 n ₁₀ = 1.51633 ν ₁₀ = 64.15

r ₁₁ = -14.8105
d ₁₁ = 0.1500
r ₁₂ = 57.3145
d ₁₂ = 2.5000 n ₁₂ = 1.69680 ν ₁₂ = 55.53
r ₁₃ = -29.3496
d ₁₃ = 0.1500
r ₁₄ = 32.6981
d ₁₄ = 4.2000 n ₁₄ = 1.69680 ν ₁₄ = 55.53
r ₁₅ = -14.0000
d ₁₅ = 1.2000 n ₁₅ = 1.84666 ν ₁₅ = 23.78

r ₁₆ = -28.9975
d ₁₆ = 2.0000
r ₁₇ = ∞
d ₁₇ = 5.0000 n ₁₇ = 1.54771 ν ₁₇ = 62.84
r ₁₈ = ∞
d ₁₈ = 2.2400 n ₁₈ = 1.54771 ν ₁₈ = 62.84
r ₁₉ = ∞
d ₁₉ = 10.0000 n ₁₉ = 1.51633 ν ₁₉ = 64.15
r ₂₀ = ∞
d ₂₀ = 3.6100

r ₂₁ = ∞
d ₂₁ = 0.7500 n ₂₁ = 1.48749 ν ₂₁ = 70.21
r ₂₂ = ∞
d ₂₂ = 1.4000
r ₂₃ (CCD 18, 19) = ∞

Second Embodiment FIG. 8 is a diagram showing a cross section perpendicular to the rotation axis of a rotating mirror of an optical system constituting an electronic imaging apparatus having a mirror scanning function according to the present embodiment. In the electronic imaging apparatus having the mirror scan function of the present embodiment, first, in order from the object side (not shown), the convex surface is directed to the object side (as the first lens having a negative refractive power constituted by a negative single lens). A first lens group 22 composed of a negative meniscus lens, a rotary mirror 12, a second lens group 23 composed of a positive lens (as a second lens group including a positive lens and having a positive refractive power), an aperture stop 13, and a negative lens A third lens group 24 having a positive refractive power as a whole is arranged and formed by a cemented negative lens 24a composed of a lens and a positive lens, a positive lens 24b, and a cemented positive lens 24c composed of a positive lens and a negative lens. An optical system 21 is configured. Further, each of lenses constituting the third lens group 24, a part or entirety thereof is adapted to be moved along the optical axis L _C. Further, on the exit side of the third lens group 24, an infrared cut filter or λ / 4 plate 15, an optical low-pass filter 16 made of a birefringent plate such as a quartz plate, and a prism 17 made of a beam splitter including a semi-transmissive surface. Is arranged. CCDs 18 and 19 are provided in the emission direction of the prism 17, and a cover glass (or positive lens) 20 is disposed between the prism 17 and the CCD 18 (not shown, but not shown) A similar cover glass or positive lens is arranged between them).

The rotation axis of the rotary mirror 12 is in a direction perpendicular to the paper surface, and the extension line of the optical axis L _C of the third lens group 24 is at a position where it intersects the mirror surface. The optical low-pass filter 16 is formed by bonding one sheet or a plurality of filters having different crystal axis directions, and the crystal axis of the filter closest to the prism 17 forms approximately 45 degrees with respect to the plate surface. 9, the orthogonal projection of the crystal axis onto the plate surface is substantially 45 degrees with respect to the rotation axis of the rotary mirror 12, and the incident light is divided into ordinary rays and extraordinary rays on the CCDs 18 and 19, respectively. It has the function of forming a double image that is slightly displaced.

The electronic image pickup apparatus having the mirror scan function of this embodiment also takes the entire object image in two shots (two shooting operations), and the CCD 18 on which light passing through the prism 17 is incident has its light receiving surface. Are arranged so that their long sides are perpendicular to the rotary mirror 12, while the CCD 19 determines the orientation of the light receiving surface accordingly. Therefore, FIG. 10 shows an object image formed by the imaging optical system 21. The upper part A of this object image is taken by the CCD 18 through the prism 17, and the lower part B Is taken by the CCD 19 after being bent by the prism 17. An arrow C in the figure indicates the direction of scanning by the rotating mirror 12.
In this way, in the electronic imaging apparatus having the mirror scan function of this embodiment, the object image is reproduced by synthesizing the four screens.

The electronic imaging apparatus having a mirror scanning function of the present embodiment, as shown in FIG. 8, the rotating mirror 12 bends the optical axis according at 45 degrees state with respect to the optical axis L _C below the 90 ° turning mirror 12 be able to. Similarly to the electronic image pickup apparatus having the mirror scan function shown in the first embodiment, the rotating mirror 12 is half the size of the angle formed by the principal ray having the maximum image height from the optical axis L _C from the illustrated position. It can be rotated within the range.

Hereinafter, numerical data of optical elements such as lenses constituting the electronic imaging apparatus having the mirror scan function according to the present embodiment will be shown.
d = 12.872 mm, n ₁ −n ₂ = 0.31769
(R ₁ + r ₂ ) / (r ₁ −r ₂ ) = 1.540

r ₁ = 58.8822
d ₁ = 1.2000 n ₁ = 1.48749 ν ₁ = 70.21
r ₂ = 12.8873
d ₂ = 20.0000
r ₃ = -77.2783
d ₃ = 1.9000 n ₃ = 1.80518 ν ₃ = 25.43
r ₄ = -16.4251
d ₄ = 4.0000
r ₅ (aperture stop 13) = ∞
d ₅ = 4.5000

r ₆ = -4.3475
d ₆ = 1.0000 n ₆ = 1.84666 ν ₆ = 23.78
r ₇ = 66.2120
d ₇ = 4.1982 n ₇ = 1.59270 ν ₇ = 35.30
r ₈ = -7.2243
d ₈ = 0.1500
r ₉ = -44.6467
d ₉ = 2.9000 n ₉ = 1.80610 ν ₉ = 40.95
r ₁₀ = -10.0511
d ₁₀ = 0.1500

r ₁₁ = 29.7815
d ₁₁ = 4.1000 n ₁₁ = 1.48749 ν ₁₁ = 70.21
r ₁₂ = -9.6246
d ₁₂ = 1.0000 n ₁₂ = 1.80100 ν ₁₂ = 34.97
r ₁₃ = -33.0347
d ₁₃ = 2.0000
r ₁₄ = ∞
d ₁₄ = 5.0000 n ₁₄ = 1.54771 ν ₁₄ = 62.84
r ₁₅ = ∞
d ₁₅ = 2.2400 n ₁₅ = 1.54771 ν ₁₅ = 62.84

r ₁₆ = ∞
d ₁₆ = 10.0000 n ₁₆ = 1.51633 ν ₁₆ = 64.15
r ₁₇ = ∞
d ₁₇ = 3.6100
r ₁₈ = ∞
d ₁₈ = 0.7500 n ₁₈ = 1.48749 ν ₁₈ = 70.21
r ₁₉ = ∞
d ₁₉ = 1.3990
r ₂₀ (CCD 18, 19) = ∞

Third Embodiment FIG. 11 is a diagram showing a cross section perpendicular to the rotation axis of a rotating mirror of an optical system constituting an electronic imaging apparatus having a mirror scanning function according to the present embodiment. In the electronic imaging apparatus having the mirror scan function of the present embodiment, first, in order from the object side (not shown), the rotary mirror 12 (consisting of two or less negative lenses and one positive lens has a negative refractive power as a whole. A first lens group 31 including a negative meniscus lens 31a, a positive lens 31b, and a negative lens 31c having a convex surface facing the rotating mirror 12 (as a first lens group having a negative refractive power as a whole), an aperture stop 13, And a second lens group 32 having a positive refractive power as a whole, which is composed of a cemented negative lens 32a of a positive lens and a negative lens, a positive lens 32b, and a cemented positive lens 32c of a positive lens and a negative lens. An imaging optical system 21 is configured. Further, each lens constituting the second lens group 32, a part or entirety thereof is adapted to be moved along the optical axis L _C. Further, on the exit side of the second lens group 32, an infrared cut filter or λ / 4 plate 15, an optical low-pass filter 16 made of a birefringent plate such as a quartz plate, and a prism 17 made of a beam splitter including a semi-transmissive surface. Is arranged. CCDs 18 and 19 are provided in the emission direction of the prism 17, and a cover glass (or positive lens) 20 is disposed between the prism 17 and the CCD 18 (not shown, but not shown) A similar cover glass or positive lens is arranged between them).

The rotation axis of the rotary mirror 12 is in a direction perpendicular to the paper surface, and the extension line of the optical axis L _C of the second lens group 32 is at a position where it intersects the mirror surface. The optical low-pass filter 16 is formed by bonding one sheet or a plurality of filters having different crystal axis directions, and the crystal axis of the filter closest to the prism 17 forms approximately 45 degrees with respect to the plate surface. 12, the orthogonal projection of the crystal axis onto the plate surface is substantially 45 degrees with respect to the rotation axis of the rotary mirror 12, and the incident light is divided into ordinary rays and extraordinary rays on the CCDs 18 and 19, respectively. It has the function of forming a double image that is slightly displaced.

The electronic image pickup apparatus having the mirror scan function of this embodiment also takes the entire object image in two shots (two shooting operations), and the CCD 18 on which light passing through the prism 17 is incident has its light receiving surface. Are arranged so that their long sides are perpendicular to the rotary mirror 12, while the CCD 19 determines the orientation of the light receiving surface accordingly. Accordingly, FIG. 13 shows an object image formed by the imaging optical system 21, and the upper part A of this object image passes through the prism 17 and is imaged by the CCD 18, and the lower part B Is taken by the CCD 19 after being bent by the prism 17. An arrow C in the figure indicates the direction of scanning by the rotating mirror 12.
In this way, in the electronic imaging apparatus having the mirror scan function of this embodiment, the object image is reproduced by synthesizing the four screens.

In the electronic imaging apparatus having the mirror scan function of the present embodiment shown in FIG. 11, the position indicated by the broken line of the rotating mirror 12 is in the standard state, and in this state, the optical axis L _{C is set} to 90 ° of the rotating mirror 12. Can be bent downward. Further, the position indicated by the solid line shows a state in which the rotary mirror 12 is rotated to the maximum, and is a state in which the principal ray having the maximum image height is rotated by half of the angle formed by the optical axis L _C. It is also possible to rotate the rotating mirror 12 in the direction opposite to the direction shown in the drawing.

Hereinafter, numerical data of optical elements such as lenses constituting the electronic imaging apparatus having the mirror scan function according to the present embodiment will be shown.
d = 20.332 mm, n ₁ −n ₂ = 0.18262
(R ₁ + r ₂ ) / (r ₁ −r ₂ ) = 0.684

r ₁ = 19.6266
d ₁ = 0.9000 n ₁ = 1.51633 ν ₁ = 64.15
r ₂ = 7.7614
d ₂ = 1.6100
r ₃ = 115.0208
d ₃ = 2.000 n ₃ = 1.69895 ν ₃ = 30.12
r ₄ = -21.5499
d ₄ = 0.6000
r ₅ = 337.7486
d ₅ = 0.8000 n ₅ = 1.51633 ν ₅ = 64.15

r ₆ = 7.1085
d ₆ = 5.000
r ₇ (aperture stop 13) = ∞
d ₇ = 9.2634
r ₈ = 11.3375
d ₈ = 3.1000 n ₈ = 1.70154 ν ₈ = 41.24
r ₉ = -16.7193
d ₉ = 0.0300
r ₁₀ = -15.8998
d ₁₀ = 0.9000 n ₁₀ = 1.80100 ν ₁₀ = 34.97

r ₁₁ = 12.8490
d ₁₁ = 0.8900
r ₁₂ = -137.9874
d ₁₂ = 2.5000 n ₁₂ = 1.65844 ν ₁₂ = 50.86
r ₁₃ = -11.5502
d ₁₃ = 2.0000
r ₁₄ = 18.9077
d ₁₄ = 4.4000 n ₁₄ = 1.51742 ν ₁₄ = 52.41
r ₁₅ = -9.8436
d ₁₅ = 1.0000 n ₁₅ = 1.80518 ν ₁₅ = 25.43

r ₁₆ = -23.9131
d ₁₆ = 2.0000
r ₁₇ = ∞
d ₁₇ = 5.0000 n ₁₇ = 1.54771 ν ₁₇ = 62.84
r ₁₈ = ∞
d ₁₈ = 2.2400 n ₁₈ = 1.54771 ν ₁₈ = 62.84
r ₁₉ = ∞
d ₁₉ = 10.0000 n ₁₉ = 1.51633 ν ₁₉ = 64.15
r ₂₀ = ∞
d ₂₀ = 3.6100

r ₂₁ = ∞
d ₂₁ = 0.7500 n ₂₁ = 1.48749 ν ₂₁ = 70.21
r ₂₂ = ∞
d ₂₂ = 1.4055
r ₂₃ (CCD 18, 19) = ∞

Fourth Embodiment FIG. 14 is a diagram showing a cross section perpendicular to the optical axis of a rotating mirror of an optical system constituting an electronic imaging apparatus having a mirror scan function according to the present embodiment. In the electronic imaging apparatus having the mirror scan function of this embodiment, in order from the object side (not shown), the rotating mirror 12 (first lens group having negative refractive power and including a positive lens closest to the object side and including a negative lens) As a first lens group 41 having a negative refractive power as a whole, an aperture stop 13, a negative lens 42a, and a positive lens 42b. The imaging optical system 21 is configured by a second lens group 42 including a positive lens 42c and a positive lens 42d and having a positive refractive power as a whole. Also, among the lenses constituting the second lens group 42, a positive lens 42d is adapted to be moved along the optical axis L _C. Further, on the exit side of the second lens group 42, an infrared cut filter or λ / 4 plate 15, an optical low-pass filter 16 made of a birefringent plate such as a quartz plate, and a prism 17 made of a beam splitter including a semi-transmissive surface. Is arranged. CCDs 18 and 19 are provided in the emission direction of the prism 17, and a cover glass (or positive lens) 20 is disposed between the prism 17 and the CCD 18 (not shown, but not shown) A similar cover glass or positive lens is arranged between them).

The rotation axis of the rotary mirror 12 is in a direction perpendicular to the paper surface, and the extension line of the optical axis L _C of the second lens group 42 is at a position where it intersects the mirror surface. The optical low-pass filter 16 is formed by bonding one sheet or a plurality of filters having different crystal axis directions, and the crystal axis of the filter closest to the prism 17 forms approximately 45 degrees with respect to the plate surface. 15, the orthogonal projection of the crystal axis onto the plate surface is substantially 45 degrees with respect to the rotation axis of the rotating mirror 12, and the incident light is divided into ordinary rays and extraordinary rays on the CCDs 18 and 19. It has the function of forming a double image that is slightly displaced.

The electronic image pickup apparatus having the mirror scan function of this embodiment also takes the entire object image in two shots (two shooting operations), and the CCD 18 on which light passing through the prism 17 is incident has its light receiving surface. Are arranged so that their long sides are perpendicular to the rotary mirror 12, while the CCD 19 determines the orientation of the light receiving surface accordingly. Accordingly, FIG. 16 shows an object image formed by the imaging optical system 21, and the upper part A of this object image is taken by the CCD 18 through the prism 17, and the lower part B Is taken by the CCD 19 after being bent by the prism 17. An arrow C in the figure indicates the direction of scanning by the rotating mirror 12.
In this way, in the electronic imaging apparatus having the mirror scan function of this embodiment, the object image is reproduced by synthesizing the four screens.

In the electronic imaging apparatus having the mirror scan function of the present embodiment shown in FIG. 14, the position of the rotary mirror 12 indicated by a broken line is in the standard state, and in this state, the optical axis L _{C is set} to 90 ° of the rotary mirror 12. Can be bent downward. The position indicated by the solid line indicates a state in which the rotary mirror 12 is rotated to the maximum, and is a state in which the principal ray having the maximum image height is rotated by half of the angle formed by the optical axis L _C. Of course, the rotating mirror 12 can also be rotated in a direction opposite to the illustrated direction.

Hereinafter, numerical data of optical elements such as lenses constituting the electronic imaging apparatus having the mirror scan function according to the present embodiment will be shown.
_{d = 14.771mm, n 1 -n 2} = 0.33033
(R ₁ + r ₂ ) / (r ₁ −r ₂ ) = − 1.142

r ₁ = 19.7495
d ₁ = 2.2000 n ₁ = 1.84666 ν ₁ = 23.78
r ₂ = 298.3938
d ₂ = 0.6000
r ₃ = 47.3674
d ₃ = 0.9000 n ₃ = 1.51633 ν ₃ = 64.15
r ₄ = 4.9415
d ₄ = 4.5000
r ₅ (aperture stop 13) = ∞
d ₅ = 6.55000

r ₆ = -15.1388
d ₆ = 0.9000 n ₆ = 1.84666 ν ₆ = 23.78
r ₇ = 104.4931
d ₇ = 0.2500
r ₈ = −36.0058
d ₈ = 2.2000 n ₈ = 1.56873 ν ₈ = 63.16
r ₉ = -10.4558
d ₉ = 0.1500
r ₁₀ = 107.1696
d ₁₀ = 3.1000 n ₁₀ = 1.56873 ν ₁₀ = 63.16

r ₁₁ = -11.4135
d ₁₁ = 1.6000
r ₁₂ = 30.9530
d ₁₂ = 2.3000 n ₁₂ = 1.51633 ν ₁₂ = 64.15
r ₁₃ = -44.2824
d ₁₃ = 2.0000
r ₁₄ = ∞
d ₁₄ = 5.0000 n ₁₄ = 1.54771 ν ₁₄ = 62.84
r ₁₅ = ∞
d ₁₅ = 1.6000 n ₁₅ = 1.51633 ν ₁₅ = 64.15

r ₁₆ = ∞
d ₁₆ = 2.2400 n ₁₆ = 1.54771 ν ₁₆ = 62.84
r ₁₇ = ∞
d ₁₇ = 13.0000 n ₁₇ = 1.51633 ν ₁₇ = 64.15
r ₁₈ = ∞
d ₁₈ = 1.5000
r ₁₉ = ∞
d ₁₉ = 0.7500 n ₁₉ = 1.48749 ν ₁₉ = 70.21
r ₂₀ = ∞
d ₂₀ = 1.3953
r ₂₁ (CCD 18, 19) = ∞

In the above embodiments, r ₁ , r ₂ ,... Are curvature radii of optical element surfaces such as lenses, and d ₁ , d ₂ ,. .., N ₁ , n ₂ ,... Indicate the refractive index of each optical element, and ν ₁ , ν ₂ ,... Indicate the Abbe number of each optical element.
Note that n ₁ , n ₂ , r ₁ , r ₂ in the numerical data of each of the above-described embodiments are codes sequentially shown from the object side to the optical element, and the parameter n ₁ in each conditional expression of the present invention _{-n 2, (r 1 + r2} ) / (r 1 -r 2) do not necessarily agree with _{n 1, n 2, r 1} , r 2 in.

  As described above, the optical system for an electronic imaging apparatus having a mirror scan function according to the present invention has the following features (1) to (9) in addition to the features described in claims 1 to 4. ing.

(1) In order from the object side, a first lens group including two lenses of a negative lens and a positive lens and having a negative refractive power as a whole, a rotatable mirror and an aperture for bending the optical axis from the object point An imaging optical system comprising a stop and a second lens group having a positive refractive power that can partially or wholly move on the optical axis, and an electronic imaging device that receives light that has passed through the imaging optical system, An electronic imaging apparatus having a mirror scan function, wherein the electronic imaging apparatus is configured to be arranged and satisfies the following conditional expressions at the same time.
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
2 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <10 (3)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ is the refractive index of the positive lens located closest to the object side, and n ₁ Reference numeral ₂ denotes the refractive index of the negative lens arranged closest to the object side, and r ₁ and r ₂ denote the curvature radii of the positive lens arranged closest to the object side and the curvature radii on the image side, respectively.

(2) In order from the object side, a first lens group having negative refractive power, a rotatable mirror for bending the optical axis from the object point, a second lens group having positive refractive power, an aperture stop, and an optical axis An imaging optical system composed of a third lens group having a positive refractive power that can partially or wholly move above, and an electronic imaging device that receives light that has passed through the imaging optical system are arranged. An electronic imaging apparatus having a mirror scan function, wherein the following conditional expressions are satisfied simultaneously:
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <3 (7)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ is the refractive index of the positive lens located closest to the object side, and n ₁ Reference numeral ₂ denotes the refractive index of the negative lens arranged closest to the object side, and r ₁ and r ₂ denote the curvature radii of the positive lens arranged closest to the object side and the curvature radii on the image side, respectively.

(3) A first lens group having, in order from the object side, a rotatable mirror for bending an optical axis from an object point, two or less negative lenses, and one positive lens and having a negative refractive power as a whole. And an aperture stop and a second lens group having a positive refractive power that can move partly or entirely on the optical axis, and an electronic imaging device that receives light that has passed through the imaging optical system, An electronic imaging apparatus having a mirror scan function, wherein the following conditional expressions are satisfied simultaneously:
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
−1 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <1 (11)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ is the refractive index of the positive lens located closest to the object side, and n ₁ Reference numeral ₂ denotes the refractive index of the negative lens arranged closest to the object side, and r ₁ and r ₂ denote the curvature radii of the positive lens arranged closest to the object side and the curvature radii on the image side, respectively.

(4) A first lens having a negative refracting power as a whole, comprising a rotatable mirror for bending the optical axis from the object point, a positive lens, and a negative meniscus lens having a convex surface facing the object side in order from the object side. An imaging optical system comprising a second lens group having a group, an aperture stop, a negative lens, and three positive lenses, the positive lens closest to the image side being movable on the optical axis and having a positive refractive power as a whole; An electronic imaging device having a mirror scan function, wherein an electronic imaging device that receives light that has passed through the imaging optical system is arranged and satisfies the following conditional expressions at the same time:
7 mm <d <25 mm (1)
0.1 <n ₁ −n ₂ <0.4 (2)
−3 <(r ₁ + r ₂ ) / (r ₁ −r ₂ ) <0
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ is the refractive index of the positive lens located closest to the object side, and n ₁ Reference numeral ₂ denotes the refractive index of the negative lens arranged closest to the object side, and r ₁ and r ₂ denote the curvature radii of the positive lens arranged closest to the object side and the curvature radii on the image side, respectively.

  (5) A semi-transparent mirror that divides light into a direction in which an optical axis is bent and a through direction is disposed between the imaging optical system and the electronic imaging device. An electronic imaging apparatus having a mirror scan function according to any one of (1) to (4).

  (6) The long side direction of the electronic imaging device is made to coincide with a direction substantially parallel to the rotation axis of the rotatable mirror, and the bending direction of the optical axis by the semi-transparent mirror is set to the rotation axis of the rotatable mirror. 4. The electronic image pickup apparatus having a mirror scan function according to claim 3, wherein the electronic image pickup apparatus is vertical.

  (7) The long side direction of the electronic imaging device is made to coincide with a direction substantially perpendicular to the rotation axis of the rotatable mirror, and the bending direction of the optical axis by the semi-transparent mirror is set to the rotation axis of the rotatable mirror. The electronic imaging apparatus having a mirror scan function according to claim 4, wherein the electronic imaging apparatus has a parallel direction.

  (8) An optical low-pass filter using crystal birefringence is disposed between the imaging optical system and the semi-transparent mirror, or (1) to (7) above. An electronic imaging apparatus having a mirror scan function according to any one of the above.

  (9) Of the optical low-pass filter, the azimuth angle of the orthogonal projection image onto the imaging plane by the imaging optical system of the crystal axis of the filter disposed closest to the semi-transparent mirror is the rotatable mirror The electronic imaging apparatus having a mirror scan function according to (8), wherein the angle is set to 40 to 50 degrees with respect to the rotation axis.

It is the schematic which shows the structure of the electronic imaging device which has a mirror scan function by this invention. It is a figure for demonstrating the arrangement configuration of CCD used in the electronic imaging device which has a mirror scan function by this invention. 1 is a lens configuration diagram of an optical system constituting an electronic imaging apparatus having a mirror scan function of the present invention, (a) is a cross-sectional view taken along the optical axis of the optical system, and (b) is a rotation axis of a rotating mirror viewed from above. The figure which shows the cross section of the surface containing X, (c) is a figure which shows a cross section perpendicular | vertical to the rotating shaft of the rotating mirror seen from the side. It is a figure for demonstrating the imaging state in CCD of the object image formed by the imaging optical system with which the electronic imaging device which has a mirror scan function of this invention is equipped. It is a figure which shows a cross section perpendicular | vertical to the rotating shaft of the rotating mirror of the optical system which comprises the electronic imaging device which has a mirror scanning function concerning 1st Example of this invention. It is a figure for demonstrating the direction of the orthogonal projection to the board surface of the crystal axis of the optical low-pass filter used for the electronic imaging device which has a mirror scan function of 1st Example, and the rotating shaft of a rotating mirror. It is a figure for demonstrating the imaging state in CCD of the object image formed by the imaging optical system with which the electronic imaging device which has a mirror scan function of 1st Example is equipped. It is a figure which shows a cross section perpendicular | vertical to the rotating shaft of the rotary mirror of the optical system which comprises the electronic imaging device which has a mirror scan function concerning 2nd Example. It is a figure for demonstrating the direction of the orthogonal projection to the plate | board surface of the crystal axis of the optical low-pass filter used for the electronic imaging device which has a mirror scan function of 2nd Example, and the rotating shaft of a rotating mirror. It is a figure for demonstrating the imaging state in CCD of the object image formed by the imaging optical system with which the electronic imaging device which has a mirror scan function of 2nd Example is equipped. It is a figure which shows a cross section perpendicular | vertical to the rotating shaft of the rotating mirror of the optical system which comprises the electronic imaging device which has a mirror scanning function concerning 3rd Example. It is a figure for demonstrating the direction of the orthogonal projection to the board surface of the crystal axis of the optical low-pass filter used for the electronic imaging device which has a mirror scan function of 3rd Example, and the rotating shaft of a rotating mirror. It is a figure for demonstrating the imaging state in CCD of the object image formed by the imaging optical system with which the electronic imaging device which has a mirror scan function of 3rd Example is equipped. It is a figure which shows a cross section perpendicular | vertical to the rotating shaft of the rotating mirror of the optical system which comprises the electronic imaging device which has a mirror scanning function concerning 4th Example. It is a figure for demonstrating the direction of the orthogonal projection to the plate | board surface of the crystal axis of the optical low-pass filter used for the electronic imaging device which has a mirror scan function of 4th Example, and the rotating shaft of a rotating mirror. It is a figure for demonstrating the imaging state in CCD of the object image formed by the imaging optical system with which the electronic imaging device which has a mirror scan function of 4th Example is equipped.

Explanation of symbols

1,12 Rotating mirror 2,13 Aperture stop 3,14,23,32,42 Second lens group 4,16 Optical low-pass filter 5,17 Semi-transparent mirror (prism)
6, 7, 18, 19 CCD
8, 9, 14c, 24b, 31b, 32b, 41a, 42b, 42c Positive lens 10, 21 Imaging optical system 11, 22, 31, 41 First lens group 11a, 31a, 41b Negative meniscus lens 11b, 31c Positive meniscus Lens 14a, 14b, 14d, 24c, 32c Joint positive lens 24a, 32a, 42a Joint negative lens 15 Infrared cut filter 20 Cover glass 24 Third lens group

Claims (11)

In order from the object side, a first lens group having a negative refractive power, which is composed of a single negative lens, a rotatable mirror for bending the optical axis from the object point, and a positive lens, have a positive refractive power. An imaging optical system comprising two lens groups, an aperture stop, and a third lens group having a positive refractive power that can move partially or entirely on the optical axis, and electrons that receive light that has passed through the imaging optical system An electronic imaging apparatus having a mirror scan function, wherein an imaging device is arranged and configured to satisfy the following conditional expressions at the same time:
7mm <d <25mm (1)
0.1 <n ₁ -N ₂ <0.4 (2)
1 <(r ₁ + R ₂ ) / (R ₁ -R ₂ <3 (7)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ Is the refractive index of the positive lens located closest to the object side, n ₂ Is the refractive index of the negative lens located closest to the object side, r ₁ , R ₂ Indicates the radius of curvature of the object side and the image side of the positive lens disposed closest to the object side. 2. The electronic image pickup apparatus having a mirror scan function according to claim 1, wherein the following conditional expression is satisfied instead of the conditional expression (1).
10mm <d <20mm .... (8) 2. The electronic imaging apparatus having a mirror scan function according to claim 1, wherein the following conditional expression is satisfied instead of the conditional expression (2).
0.2 <n ₁ -N ₂ <0.4 (9) 2. The electronic image pickup apparatus having a mirror scan function according to claim 1, wherein the following conditional expression is satisfied instead of the conditional expression (7).
1.2 <(r ₁ + R ₂ ) / (R ₁ -R ₂ <2 (10) In order from the object side, a first lens group having a negative refractive power as a whole and an aperture stop, which is composed of a rotatable mirror for bending an optical axis from an object point, two or less negative lenses, and one positive lens. And an image pickup optical system including a second lens group having a positive refractive power that can partially or wholly move on the optical axis, and an electronic imaging device that receives light that has passed through the image pickup optical system. An electronic image pickup apparatus having a mirror scan function, which is configured to satisfy the following conditional expressions at the same time.
7mm <d <25mm (1)
0.1 <n ₁ -N ₂ <0.4 (2)
-1 <(r ₁ + R ₂ ) / (R ₁ -R ₂ <1 (11)
Where d is the distance between the rotation center position of the rotatable mirror and the pupil position of the imaging optical system viewed from this position, n ₁ Is the refractive index of the positive lens located closest to the object side, n ₂ Is the refractive index of the negative lens located closest to the object side, r ₁ , R ₂ Indicates the radius of curvature of the object side and the image side of the positive lens disposed closest to the object side. 6. The electronic imaging apparatus having a mirror scan function according to claim 5, wherein the following conditional expression is satisfied instead of the conditional expression (1).
15mm <d <23mm (12) 6. The electronic imaging apparatus having a mirror scan function according to claim 5, wherein the following conditional expression is satisfied instead of conditional expression (2).
0.15 <n ₁ -N ₂ <0.4 (5) 6. The electronic imaging apparatus having a mirror scan function according to claim 5, wherein the conditional expression (11) is changed to satisfy the following conditional expression.
0 <(r ₁ + R ₂ ) / (R ₁ -R ₂ <1 (13) 9. A semi-transparent mirror that divides light into a direction in which an optical axis is bent and a through direction is disposed between the imaging optical system and the electronic imaging device. An electronic imaging device having a mirror scan function. 10. The electronic image pickup apparatus having a mirror scan function according to claim 9, wherein an optical low-pass filter using crystal birefringence is disposed between the imaging optical system and the semi-transparent mirror. Of the optical low-pass filter, the azimuth angle of the orthogonal projection image of the crystal axis of the filter disposed at the position closest to the semi-transparent mirror to the imaging plane by the imaging optical system is the rotation axis of the rotatable mirror. The electronic image pickup apparatus having a mirror scan function according to claim 10, wherein the electronic image pickup apparatus has a mirror scan function of 40 to 50 degrees with respect to the angle.

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