JPH1055022A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image pickup device for picking up an image by dividing a picture, more compact. SOLUTION: The luminous flux for an objective to be picked up for forming an image pickup screen 30 with an image pickup optical system is divided into plural divided image pickup screens 31, 32, 33 and 34 by the luminous flux shifting units 20A, 20B, 20C and 20D of a luminous flux dividing/shifting means 20 arranged in mid-way of the optical path of the image pickup optical system and the plural divided image pickup screens 31, 32, 33 and 34 are shifted in parallel in directions where they are away from each other. At this time, on the divided image pickup screens 311, 321, 331 and 341 after being divided/ shifted, the images are picked up by different image pickup means respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus which divides one image pickup screen into a plurality of parts and picks up each divided screen with a different image pickup device.

[0002]

2. Description of the Related Art In recent years, so-called digital cameras (electronic still cameras) have been developed in which an image of a subject is picked up by a CCD image pickup device instead of a silver halide film and recorded as an electric signal. For example, there is a digital camera in which a photographic lens and a body of a single-lens reflex camera for a silver halide film are diverted and a CCD image pickup device is arranged at a film surface position (a pressure plate position).

However, the light receiving surface size (effective screen size) of a general CCD image pickup device is only about 6.6 × 8.8 mm even in a so-called 2/3 inch type CCD image pickup device. On the other hand, the screen size of a Leica SLR camera using a general silver halide film (hereinafter referred to as “Leica camera”) is 24 × 36 mm. Therefore, in a configuration in which the film of the Leica camera is simply replaced with a 2/3 inch CCD image sensor, the screen size of a digital camera is about 1/4 on one side. In other words, if the interchangeable lens of the Leica version camera is used as it is for a digital camera, a lens having the same focal length but a focal length of about 1/4 must be used. For example, if an interchangeable lens having a focal length of 50 mm of a Leica version camera is used as it is, an electronic still video camera corresponds to an angle of view of a 200 mm focal length of a Leica version camera. Interchangeable lenses for Leica version cameras are generally those with a focal length of 20 to 300 mm.However, with these interchangeable lenses, in digital cameras, the focal length is equivalent to 80 to 1200 mm in terms of Leica version, so-called Imaging from a wide angle to a standard angle of view could not be performed.

[0004] Moreover, inexpensive CCD imaging devices that are currently in widespread use have a small number of pixels per unit area, and have a lower resolution than silver halide films. Therefore, the subtle texture expressed by the silver halide film cannot be expressed by the CCD image pickup device, and it is difficult to obtain a beautiful work. A high-resolution CCD image sensor having a large number of pixels per unit area is very expensive, and a digital camera using the high-resolution CCD image sensor becomes very expensive.

[0005] In a CCD image pickup device, a substrate portion that cannot receive light generally exists around a light receiving surface. Therefore, when the CCD image pickup devices are arranged on the same plane, the substrate portions adjacent to each other mechanically interfere with each other, so that the light receiving surfaces cannot be arranged adjacent to each other.

As means for solving such a problem, there has been known a method in which an imaging range is divided into a plurality of regions, and each divided imaging region is imaged by a low-resolution CCD imaging device. For example, a reflector having a plurality of reflecting surfaces is arranged in the optical path of the imaging optical system, the optical path is divided, and the subject light flux in each of the optical paths is received by a CCD image pickup device arranged on an image forming plane, and is imaged. Then, an image captured by each CCD image sensor is combined to form one screen.

As the optical path dividing means, a roof-shaped reflector is known for dividing the optical path into two or more, and a polygonal pyramid-shaped reflector is known for dividing the optical path into three or more. 191678, JP-A-4-114573, JP-A-4-145
No. 74, JP-A No. 4-244791).

However, in the conventional optical path splitting means, when the optical path is split, a single reflecting surface for splitting a light beam directed toward one image sensor is formed. Therefore, each reflecting surface becomes large, and it is difficult to reduce the size of the camera. In addition, according to the conventional optical path dividing means, the image pickup devices cannot be directed in the direction orthogonal to the optical axis of the image pickup lens before the light beam splitting, and thus are arranged discretely. Therefore, a large space for accommodating the imaging element and the peripheral electric circuit is required, and there is a problem that the entire camera becomes large.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to further reduce the size of an image pickup apparatus that divides a screen into an image.

[0010]

According to the first aspect of the present invention, a light beam forming a different part of a subject image by an image pickup optical system is split by a light beam splitting shift means arranged in the optical path of the image pickup optical system. In addition, different portions of the subject image are separated from each other by being shifted in parallel in the direction in which they are separated from each other, and the separated portions of the subject image are imaged by different image pickup means.

The light beam splitting / shifting means includes a plurality of units in which a plurality of light beam shift optical elements for shifting a subject light beam forming each divided portion of the subject image in parallel in a direction away from the optical axis are in close contact with each other. Each unit divides a subject light beam to form a divided subject image.

The light beam shifting optical element includes a first reflecting surface that reflects a light beam incident parallel to the optical axis in a direction away from the optical axis, and a light beam reflected by the first reflecting surface in a direction parallel to the incident light beam. And a second reflection surface that reflects light.

The light beam shifting optical element of each unit includes a first reflecting surface that reflects a light beam incident parallel to the optical axis in a direction away from the optical axis, and a light beam reflected by the first reflecting surface as the incident light beam. A second reflecting surface that reflects light in a parallel direction, wherein the first reflecting surface is arranged to reflect light rays parallel to the optical axis in a direction orthogonal to each side of the imaging screen.

The light beam shifting optical element of each unit is as follows:
It is formed by a plurality of prisms whose cross section parallel to the shift direction has a parallelogram.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view for explaining the operation of a light beam splitting and shifting means 10 of the present invention for splitting a subject light beam and shifting each split light beam. In this figure, an imaging lens and an imaging device (not shown) are arranged on the left and right sides of the light beam splitting shift unit 10.

The light beam splitting / shifting means 10 includes a pair of reflecting surfaces 11 having the same length and arranged in parallel to face each other.
It has 12. When the incident end point of the first reflection surface 11 is A, the exit end point is B, the incident end point of the second reflection surface 12 is C, and the exit end point is D, a straight line passing through the incident end points A and C;
A straight line passing through the exit-side end points B and D is orthogonal to the optical axis O of the imaging lens, and a straight line connecting the end points C and B is arranged so as to be parallel to the optical axis O. ∠ABE = ∠CDB = θ, and in the illustrated embodiment, it is set so that θ = 45 degrees. Each of the reflection surfaces 11 and 12 extends in a direction orthogonal to the paper surface. Further, the optical axis O of the reflection surfaces 11 and 12
The thickness in the direction parallel to the above, that is, the interval between the points CB is d.

The first reflecting surface 1 passes through the point P and is parallel to the optical axis O.
The light ray incident on the point Q of No. 1 is reflected at the point Q in the direction of the second reflecting surface 12 and is reflected at the point R of the second reflecting surface 12 in a direction parallel to the incident light beam PQ. The ray RS reflected at the point R is parallel to the incident ray PQ, and has an optical axis O with respect to the ray PQ.
In the direction away from the plane L by a length L in parallel.
That is, the image plane formed by the light rays incident between the reflection surfaces 11 and 12 is separated from the optical axis O by the length L by the reflection surfaces 11 and 12. By arranging the first reflection surface 11 and the second reflection surface 12 a predetermined number of times, a light beam or an optical path in a certain region can be shifted by a certain length.

The image plane formed by the light beams reflected by the reflecting surfaces 11 and 12 is a light beam splitting and shifting means by the sum of the length L and the thickness d of the reflecting surfaces 11 and 12 in the direction parallel to the optical axis O. It is approaching 10. Therefore, the image pickup means has a length L from the optical axis O as compared with a case where the light beam shift means 10 is not provided.
And a distance (L + d) / n closer to the imaging lens (where n is the light beam shifting means 10).
). In the illustrated embodiment, since the angle θ formed between the reflection surfaces 11 and 12 and the optical axis O is 45 degrees, the thickness d of the reflection surfaces 11 and 12 in the direction parallel to the optical axis O is set.
Is equal to the shift amount L. The square ACDB is a parallelogram.

Next, the present invention will be described more specifically. The reflection surfaces 11 and 12 can be formed by depositing a metal film such as aluminum or silver on the surface (boundary surface) of an optical element such as a prism. For example, the reflecting surfaces 11 and 12 are formed by opposing parallel planes of a prism having a cross section of a parallelogram ABDC. After a metal film is vapor-deposited on the reflecting surfaces 11 and 12 of each of the predetermined number of prisms, the reflecting surfaces 12 and 11 of the other prisms are closely adhered to each other so that the incident end face on which the subject light flux enters and the exit end face on which the light exits are parallel. One light beam splitting shift unit (unit) forming a plane is formed.

A plurality of the light beam splitting shift units are arranged in the middle of the imaging optical path, and the transmitted light beams are shifted in parallel in different directions by the respective light beam splitting shift units to divide the imaged screen into a plurality of portions. Thus, the divided imaging screens can be separated from each other. If each of the divided imaging screens is separated from each other, the imaging elements that respectively image each of the divided imaging screens are also separated from each other,
A plurality of image sensors can be arranged on the same surface without mechanical interference with each other.

An embodiment in which the imaging screen 30 is divided into four parts will be described below.
This is shown in FIG. 2 and FIG. In these embodiments, the imaging screen 30 is divided into four by a vertical line and a horizontal line (orthogonal cross line) passing through the optical axis O, and the divided imaging screens 31, 32, 33, and 3 are divided.
4 at divided positions from each other.
1, 331 and 341.

In the embodiment shown in FIG. 2, the image pickup screen 30 is divided by the light beam division shift means 20 into divided image pickup screens 31, 32,.
It is characterized in that it is divided into 33 and 34 and separated from each other in the vertical and horizontal directions. In this embodiment, the light beam splitting / shifting means 20 is formed of four light beam shift units (units) 20A, 20B, 20C, and 20D, and these are arranged in the optical path. In the figure, the light beam shift unit 20A vertically moves the divided image pickup screen 31 upward, the light beam shift unit 20B moves the divided image pickup screen 32 horizontally rightward, and the light beam shift unit 20C transmits the divided image pickup screen 3
3 vertically downward, and the divided imaging screen 20D is divided imaging screen 3
4 in the horizontal right direction by a distance L.

In the first embodiment, the divided imaging screen is shifted in the horizontal direction and the vertical direction with respect to the imaging screen. In FIG. 3, each divided imaging screen is shifted in the diagonal direction of the imaging screen. An embodiment is shown. In this embodiment, the parallelogram prism is arranged in a direction orthogonal to the diagonal line of the imaging screen to form the light beam splitting / shifting means 40. The light beam splitting / shifting means 40 includes four light beam shift units 40A, 40B, 40C, and 40D. Each of the light beam shift units 40A to 40D divides the imaging screen 30 into four parts by cross lines that pass through the optical axis and are orthogonal to each other. The imaging screens 31, 32, 33, and 34 are shifted in parallel by a predetermined length toward the diagonally outside of the imaging screen 30 to form divided imaging screens 312, 322, 332, and 342, respectively.

FIG. 4 shows an embodiment of the parallelogram prism 23 constituting the light beam splitting / shifting means 20 (light beam shift units 20A to 20D). The parallelogram prism 23 has an incident end surface 23 on which the subject light beam enters.
a, an emission end surface 23c for emitting light, a first reflection surface 23b constituting the first reflection surface 11, a second reflection surface 23d constituting the second reflection surface 12, and both end surfaces 23e and 23f orthogonal to these surfaces. ing. The entrance end surface 23a, the exit end surface 23b, the first reflection surface 23b, and the second reflection surface 23d are mirror-finished (parallel flat surfaces), and the end surfaces 23e and 23f are rough surfaces. Then, the reflection surfaces 23b and 23d
A metal such as aluminum or silver is vapor-deposited on the outer surface of the device to form a reflecting mirror. Ghosts and the like can be prevented by performing antireflection processing such as black paint on the outer surfaces of the end surfaces 23e and 23f.

FIG. 5 shows a structure in which a plurality of parallelogram prisms 23 are combined to constitute one light beam shift unit. FIG. 6 shows the light beam shift unit 20C shown in FIG. The structure when the quadrilateral prism 23 is mainly formed is shown. In FIG.
In this light beam shifting unit 20C, the triangular prism 21 at the boundary contacting the other light beam shifting unit 20D is formed by a prism having a right-angled triangular cross section, and a prism group connected to the triangular prism 21 is converted into a parallelogram prism 23 having a rhombic cross section.
The outermost prism 25 is formed by a triangular prism having a right-angled triangular cross section. Triangular prism 21, 25
Has the same shape as that obtained by dividing the parallelogram prism 23 into two along its diagonal. And the triangular prism 21
Is such that the apex 21a is located on the incident side, the side 21b is located on the side in contact with the adjacent light beam shift unit 20D, the bottom (bottom) 21c is located on the exit side, and the side 21b is located on the optical axis O.
The bottom surface 21c is arranged in a direction orthogonal to the optical axis O. That is, the light beam incident on the incident side surface 23a of the adjacent parallelogram prism 23 is directed in a certain direction (downward in the figure).
To shift to. Since the outer triangular prism 25 is for forming the second reflecting surface of the outermost parallelogram prism 23, the parallelogram prism 23 may be used as it is. Also, triangular prism 2
1 may not be optically necessary.

In the first embodiment shown in FIG. 2, the light beam shift units 20A to 20D can be formed using the same parallelogram prism 23. Further, the light beam shift unit 20A and the third light beam shift unit 20C, the light beam shift unit 20B, and the fourth light beam shift unit 20C which are located diagonally have the same structure. The light beam shift units 20A and 20C and the light beam shift unit 20B,
20D has basically the same configuration as that of the light beam shift unit 20C except that the outer shape is different. If the light beam shift units 20A to 20D are square, they can all be the same.

When the optical path shift means 30 is present,
The divided imaging planes 31 to 34 are closer to the optical path shift unit by (d + L) / n than the image forming position when the optical path shift unit 30 is not present. Here, n is the refractive index of the light beam shift units 20A, 20B, 20C, and 20D.

FIG. 7 shows that the prisms 21, 23, 25
The light beam splitting shift means 50 sandwiched between two parallel flat glass plates 26 and 27 is shown. According to this configuration, the connection and positioning of the prisms 21, 23, and 25 are easy, and they are not separated or shifted. The connection of each unit is also performed by this parallel flat glass plate 2.
6, 27 can be used.

FIG. 8 uses the light beam division shift means 50 (only the units 50A and 50B are shown) shown in FIG.
FIG. 1 is a diagram illustrating an embodiment of an imaging apparatus according to the present invention, which captures an image at only 62. In this embodiment, a zoom lens 60 is applied as an imaging lens, and FIG. 8A shows a state at the telephoto end, and FIG. 8B shows a state at the wide end.

As described above, since the light beam splitting and shifting means according to the embodiment of the present invention has a plate shape extending in the direction perpendicular to the optical axis, the thickness and the volume are small as a whole. In addition, the divided imaging planes are oriented in a direction perpendicular to the optical axis and can be shifted to such an extent that the imaging elements do not interfere with each other.

In the above-described embodiment, the imaging screen is divided into four parts. However, the present invention is not limited to this. FIG. 9 shows the shift direction of the light beam shift unit when dividing the imaging screen into six parts, and FIG. 10 shows the shift direction of the light beam shift unit when dividing the imaging screen into nine parts. In the embodiment of dividing into six,
The light flux shifting means 72 and 75 at the upper and lower centers are of the type shown in FIG.
The four corner light beam shifting means 71, 73, 74 and 76 are of the type shown in FIG. 3, and shift the light beam outward in a diagonal direction or outward directions orthogonal to each other. In the nine-division embodiment, the center light beam shift unit 85 is a simple plane-parallel plate that does not shift.
Luminous flux shift units 81, 83, 87, 89 at the corners
3 is of the type shown in FIG. 3 and shifts the luminous flux in the diagonal direction, respectively. Shift in the direction. At this time, the light beam shift unit 85 determines the thickness according to the position of the corresponding imaging surface in the optical axis direction. For example, if the imaging surface of the light beam shift unit 85 is arranged on the same plane as the imaging surfaces of the other light beam shift units, the thickness of the light beam shift unit 85 is (d + L).

Although the embodiment of the present invention has been described with respect to the case where the present invention is applied to the imaging screen size in the Leica version, a so-called new system (Advanced Photo Syste
m) More effective for compatible cameras. The new system has a shooting screen size of 16.7mm x 30.2mm,
It is close to the image screen size of a CD image sensor. Therefore, when the taking lens of the camera equipped with the imaging device of the present invention is shared with the taking lens of the camera to which the new system is applied,
The angle of view can be made more consistent.

[0033]

As is clear from the above description, the present invention
A subject light beam that forms a subject image formed by the imaging optical system is divided into a plurality of portions by a light beam splitting / shifting unit disposed in the middle of the optical path of the imaging optical system, and is shifted in parallel in directions away from each other. Since the divided subject images formed by the divided and shifted subject luminous fluxes are respectively captured by different imaging means, the divided imaging can be performed with a simple configuration without increasing the optical path length and the overall volume. Further, the present invention provides the first,
A plurality of light beam shifting means in which a plurality of reflecting members having a second reflecting surface are arranged are arranged in the middle of the optical path by combining a plurality of light beam shifting means. Each of the divided screens can be imaged by the element.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the operation of an optical path shifting means of the present invention.

FIG. 2 is a perspective view showing a first embodiment of the imaging apparatus of the present invention.

FIG. 3 is a perspective view showing a second embodiment of the imaging apparatus of the present invention.

FIG. 4 is a diagram showing an appearance of a prism according to the first embodiment shown in FIG.

FIG. 5 is a diagram showing how a light beam shift unit is configured by combining the prisms shown in FIG. 4;

FIG. 6 is an enlarged view of one of the light beam shift units shown in FIG. 2;

FIG. 7 is a side view showing another embodiment of the light beam shift unit shown in FIG. 5;

FIG. 8 is a diagram illustrating a state of light rays of a zoom lens camera to which the imaging apparatus of the present invention is applied in a long focus state and a single focus state.

FIG. 9 is a diagram illustrating a light beam shift direction of each light beam shift unit in an embodiment in which an imaging screen is divided into six.

FIG. 10 is a diagram illustrating a light beam shift direction of each light beam shift unit in an embodiment in which an imaging screen is divided into nine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 1st reflection surface 12 2nd reflection surface 20 Flux division | shift shift means 20A Flux shift unit 20B Flux shift unit 20C Flux shift unit 20D Flux shift unit 30 Imaging screen 31 Division imaging screen 32 Division imaging screen 33 Division imaging screen 34 Division imaging screen 34 Division imaging screen 40 light beam splitting / shifting means 40A light beam shift unit 40B light beam shift unit 40C light beam shift unit 40D light beam shift unit

Claims (11)

[Claims] 1. A light beam forming different portions of a subject image by an imaging optical system is split by a light beam splitting / shifting means arranged in the optical path of the imaging optical system, and the split light beams are shifted in parallel in directions away from each other. An image capturing apparatus, wherein different portions of the subject image are separated from each other, and the separated portions of the subject image are captured by different image capturing means. 2. A unit in which a plurality of light beam shift optical elements for closely shifting a subject light beam which forms each divided part of the subject image in parallel in a direction away from an optical axis are arranged in parallel. The imaging apparatus according to claim 1, further comprising: a plurality of units, each unit dividing a subject light beam to form a divided subject image. 3. The light beam shifting optical element includes: a first reflecting surface that reflects a light beam incident parallel to an optical axis in a direction away from the optical axis; and a light beam reflected by the first reflecting surface as an incident light beam. The imaging device according to claim 1, further comprising a second reflection surface that reflects light in a parallel direction. 4. The imaging apparatus according to claim 2, wherein the unit includes four units that divide the imaging screen into four around the optical axis. 5. The light-shifting optical element of each unit includes: a first reflecting surface that reflects a light beam incident parallel to an optical axis in a direction away from the optical axis; and a light beam reflected by the first reflecting surface. A second reflecting surface that reflects light in a direction parallel to an incident light beam, wherein the first reflecting surface is arranged in a direction to reflect a light beam parallel to the optical axis in a direction orthogonal to each side of the imaging screen. The imaging device according to claim 4, wherein: 6. The light beam shifting optical element of each unit includes a first reflecting surface that reflects a light beam incident parallel to an optical axis in a direction away from the optical axis, and a light beam reflected by the first reflecting surface. A second reflecting surface that reflects light in a direction parallel to the incident light beam, wherein the first reflecting surface is arranged in a direction to reflect a light beam parallel to the optical axis in a direction parallel to a diagonal line of the photographing screen. The imaging device according to claim 4, wherein: 7. The light beam shifting optical element of each unit is formed of a plurality of prisms whose cross-section parallel to the shift direction has a parallelogram shape. Imaging device. 8. The imaging device according to claim 7, wherein the plurality of prisms of each unit are sandwiched between transparent parallel flat plates. 9. The imaging apparatus according to claim 2, wherein the unit includes six units that divide an imaging screen into six. 10. The imaging apparatus according to claim 2, wherein the unit includes nine units for dividing an imaging screen into nine. 11. The light-shifting optical element of each unit is formed of a prism in which a metal reflection film is deposited on a first reflection surface and a second reflection surface. Imaging device.