JPH09214992A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device in which a light receiving plane can be extended and the number of picture elements can be increased in a simple configuration. SOLUTION: This device is provided with an optical path dividing optical element 20 for the reflecting light flux from an image pickup lens and dividing it into plural pieces of light flux and plural CCD imaging devices 31, 32, 33 and 34 for receiving the respective pieces of light flux divided by the optical path dividing optical element 20. Then, concerning the dividing optical element 20, reflection planes 21, 22 and 23 for dividing the light flux of an object and making it incident to the CCD imaging devices 31, 32 and 33 are formed on three side faces among four side faces of a square pyramid and at a part corresponding to the other one side face, a transmission part 24 is formed by excluding this part so that the light flux made incident to this part can be transmitted through the dividing optical element 20 and can be made incident to the CCD imaging device 34.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an image pickup apparatus using a plurality of image pickup elements.

[0002]

2. Description of the Related Art Recently, an electronic still camera has been developed in which an image of an object is picked up by a CCD image pickup device instead of a silver salt film and recorded as an electric signal. For example, there is one in which a lens and a body of a single-lens reflex camera for a silver salt film are diverted and a CCD image pickup element is arranged at a film surface position (press plate position).

However, the light receiving surface size (effective screen size) of a general CCD image pickup device is only 6.6 × 8.8 mm for a so-called 2/3 inch type CCD image pickup device. On the other hand, the screen size of a Leica single-lens reflex camera (hereinafter referred to as “Leica version camera”) that uses a general silver salt film is 24 × 36 mm. Therefore, if the film of the Leica camera is simply replaced by a 2 / 3-inch CCD image sensor, the side length of the screen when using an electronic still camera is about 1/4. In other words, if the interchangeable lens of the Leica camera is used as it is for an electronic still video camera, the angle of view will be about 1/4 even if the focal length is the same. Therefore, to obtain the same angle of view as the Leica version camera, a lens with a focal length of 1/4 must be used. For example, if an interchangeable lens with a focal length of 50 mm of a Leica camera is used as it is, it will correspond to a focal length of 200 mm with a Leica camera when using an electronic still video camera. Generally, the focal length of interchangeable lenses for Leica cameras is 20 to 300 mm, but these interchangeable lenses are not suitable for electronic still cameras.
Since it was equivalent to 80-1200mm, it was not possible to shoot from the so-called wide-angle to standard angle of view.

Moreover, the inexpensive CCD image pickup device which is now popular has a small number of pixels per unit area, that is, the resolution is lower than that of the silver salt film. 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 pickup device having a large number of pixels per unit area is very expensive, and an electronic still camera using the high resolution CCD image pickup device is 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 disposed adjacent to each other.

As a means for solving such a problem, there is known one in which an image pickup range is divided into a plurality of areas and each divided image pickup area is picked up by a low resolution CCD image pickup device. For example, a reflector having a plurality of reflecting surfaces is arranged in the optical path of the photographing optical system, and the optical path is divided by reflection by the reflecting surface,
The subject light flux in each of the divided optical paths is received by the CCD image pickup device arranged on the image forming plane, and an image is picked up. And each CC
The images captured by the D image sensor are 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, the conventional optical path splitting means has a problem that the structure becomes complicated when the number of splits is increased because the splitting of the light flux is performed by the reflecting surface.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an image pickup device capable of increasing the light receiving area and increasing the number of pixels with a simple structure.

[0010]

SUMMARY OF THE INVENTION To achieve this object, an invention according to claim 1 is an optical path splitting optical element for splitting a light flux transmitted through an imaging lens into a plurality of light fluxes and forming different portions of a subject image by the respective split light fluxes. A plurality of image pickup elements for receiving each of the divided luminous fluxes, wherein the optical path splitting optical element is
It is characterized in that the light flux is divided by reflection by a reflecting surface and transmission by a transmitting portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing configurations of an optical path splitting optical element and a CCD image pickup element according to an embodiment of the present invention. In this embodiment, the subject light flux forming the entire screen (entire subject image) 10 is changed to the subject light flux forming the divided screens (divided subject images) 11, 12, 13, 14 obtained by dividing the entire screen 10 into four. The subject image corresponding to the divided screens 11, 12, 13, and 14 which is divided by the optical path (light flux) dividing optical element 20 is picked up by the four CCD image pickup elements 31, 32, 33, and 34 arranged apart from each other. This is the configuration. Each CC
The divided screen 11 is formed on the effective light receiving surface of the D image pickup devices 31 to 34.
The subject images corresponding to Nos. 14 to 14 are formed and picked up by the CCD image pickup devices 31 to 34. The divided subject images picked up by the CCD image pickup devices 31 to 34 are combined into one subject image corresponding to the entire screen 10 by image processing means (not shown).

The feature of the embodiment of the present invention is that the fourth CCD is used.
This means that the imaging element 34 is configured to form the fourth split screen 14 (divided subject image) by the subject light flux that has passed through the optical path splitting optical element 20. That is, the divided light flux forming an image on each of the CCD image pickup devices 31 to 34 is the fourth CCD image pickup device 34 unless the optical path dividing optical element 20 is present.
First, second, and third divided screens 11, 12, and 13 are formed adjacent to the upper fourth divided screen 14, and one entire screen 10 (entire subject image) is formed as a whole. Hereinafter, details of the embodiment will be described.

The optical path splitting optical element 20 has a shape in which one of the side surfaces is cut from a quadrangular pyramid and cut along an orthogonal plane passing through a perpendicular line drawn from the apex to the bottom surface. The optical path splitting optical element 20 has the first, second and third reflection surfaces 21, 22 and 23 formed on the three side surfaces, and the transmission portion 24 formed on the cut portion. In the optical path splitting optical element 20, in the camera body, with a perpendicular line dropped from the apex to the bottom surface aligned with the optical axis of the photographing lens, an orthogonal plane passing through the perpendicular line and each apex of the bottom side corresponds to the vertical direction of the photographing screen. It is arranged so as to be parallel to the left-right direction.

The subject light flux that has passed through a photographing lens (not shown) is incident on the first, second and third reflection surfaces 21, 22 and 23, and the first, second and third reflection surfaces 21, 22, 23 respectively.
Are reflected by the first, second and third CCD image pickup devices 3 respectively.
It is incident on the light receiving surfaces of 1, 32, and 33. The light flux incident on the transmissive portion 24 corresponding to the cut side surface is directly transmitted and is incident on the light receiving surface of the fourth CCD image pickup element 34. That is, the first, second, third, fourth split screens 11, 12, 13, 14
The object light flux forming the
The D image pickup elements 31, 32, 33, 34 receive the light. Therefore, the subject image 11i corresponding to the first split screen 11 is captured by the first CCD image sensor 31, the subject image 12i corresponding to the second split screen 12 is captured by the second CCD image sensor 32, and the third split screen is displayed. The subject image 13i corresponding to 13 is captured by the third CCD image sensor 33, and the subject image 14i corresponding to the fourth split screen 14 is captured by the fourth CCD image sensor 34.

The subject images 11i to 14i imaged by the CCD image pickup devices 31 to 34 are usually processed as an electric digital signal (digital video signal) by an image processing circuit and combined into one seamless image data. To be done.
The combined image data is recorded on a recording medium and used as display data on a display or print data for a printer. The optical path splitting optical element 20 is preferably arranged so that the subject images 11i to 14i overlap each other to some extent so that an image missing portion does not occur when the images are combined.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the optical path splitting optical element 202 is used.
Is formed by a combination of triangular prisms, and the first, second,
3, 4 CCD image pickup elements 312, 322, 332, 342
Is characterized in that each of the light receiving surfaces of is arranged orthogonal to the optical axis or parallel to the optical axis. Reflecting surfaces 212, 222, 2 corresponding to the three reflecting surfaces 21, 22, 23 of the first embodiment.
32 is formed by the slopes of three triangular prisms.
These triangular prisms 212, 213, and 214 are integrally formed on the common substrate 20A. The triangular prism and the substrate do not exist in the portion corresponding to the transmissive portion 242.

According to the second embodiment, the first, second and third reflection surfaces 2 of the subject light flux transmitted through the photographing lens are used.
The ones incident on 12, 222, and 232 are the first and
It is reflected by the second and third reflection surfaces 212, 222, and 232, and respectively reflected by the first, second, and third CCD image pickup elements 312, 322, and 33.
An image is formed on the light receiving surface of 2. The light flux incident on the transmission part 242 where the triangular prism does not exist proceeds as it is to the fourth CC.
An image is formed on the D image sensor 342.

FIGS. 3 and 4 are ray tracing diagrams when the second embodiment is applied to a camera having a zoom lens. FIG. 3 is a view at the time of telephoto shooting (long focal length) in which the front lens group L1 and the rear lens group L2 are close to each other,
FIG. 4 shows a state of light rays in wide-angle photography (short focal length) in which the rear lens group L2 is retracted.

FIG. 5 shows a third embodiment of the present invention. The third embodiment is characterized in that the optical path splitting optical element 203 is composed of a mirror, and that the reflecting surface formed by the triangular prism in the second embodiment is formed by a flat mirror. According to the optical path splitting optical element 203, of the subject light flux that has passed through the taking lens, those incident on the first, second and third reflection surfaces 213, 223 and 233 are the first, second and third reflection surfaces 213 and 22 respectively.
The light is reflected by 3, 233 and forms an image on the light receiving surfaces of the first, second and third CCD image pickup devices 313, 323 and 333, respectively.
The light flux incident on the transmission part 243 where no mirror exists advances as it is and forms an image on the fourth CCD image pickup element 343.

FIGS. 6 and 7 are ray tracing diagrams when the third embodiment is applied to a camera having a zoom lens. FIG. 6 is a view at the time of telephoto shooting (long focal length) in which the front lens group L1 and the rear lens group L2 are close to each other,
FIG. 7 shows a state of light rays in wide-angle photography (short focal length) in which the rear lens group L2 is retracted.

As described above, the illustrated embodiment shows an example in which the image pickup screen is divided into four, but the present invention does not limit the number of divisions. Although the CCD image pickup device is shown as the image pickup device, other solid-state image pickup devices may be used.

[0022]

As is clear from the above description, the present invention
An optical path dividing optical element that reflects the light beam emitted from the image pickup lens and divides the light beam into a plurality of light beams, and a plurality of image pickup elements that receive the respective divided light beams, and at least one of the divided light beams is provided. Since the light flux is not reflected by the optical path splitting optical element, it is possible to increase the total number of pixels per image with a simple configuration. Moreover, since the area of the light-receiving surface can be expanded with a simple configuration, it is possible to shoot at a field angle closer to that when shooting a silver salt film by using a conventional shooting lens and a camera body for shooting a silver salt film. Further, since the reduction optical system is unnecessary or the reduction ratio is low even if the reduction optical system is used, it becomes easy to correct various aberrations of the reduction optical system and the size can be further reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of an image pickup apparatus of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the image pickup apparatus of the present invention.

FIG. 3 is a diagram showing a state of light rays at the time of telephoto shooting in the zoom lens camera to which the second embodiment is applied.

FIG. 4 is a diagram showing a state of light rays during wide-angle shooting in a zoom lens camera to which the second embodiment is applied.

FIG. 5 is a perspective view showing a third embodiment of the image pickup apparatus of the present invention.

FIG. 6 is a diagram showing a state of light rays at the time of telephoto shooting in the zoom lens camera to which the third embodiment is applied.

FIG. 7 is a diagram showing a state of light rays at wide-angle shooting in a zoom lens camera to which the third embodiment is applied.

[Explanation of symbols]

 11 1st split screen 12 2nd split screen 13 3rd split screen 14 4th split screen 20 Optical path splitting optical element 202 Optical path splitting optical element 203 Optical path splitting optical element 21 1st reflective surface 22 2nd reflective surface 23 3rd reflective surface 24 Transmission Part 31 First CCD Image Sensor 32 Second CCD Image Element 33 Third CCD Image Element 34 Fourth CCD Image Element

Claims (5)

[Claims] 1. An optical path splitting optical element for splitting a light flux transmitted through an image pickup lens into a plurality of light fluxes to form different parts of a subject image by the respective split light fluxes, and a plurality of image pickup elements for receiving each of the split light fluxes. And an optical path splitting optical element splitting the light flux by reflection by a reflection surface and transmission by a transmission unit. 2. The light flux split by the optical path splitting optical element according to claim 1 is a light flux that forms a divided portion of an entire subject image formed when the image pickup element is not split. An imaging apparatus, wherein the entire subject image is formed by combining divided subject images formed by the received light flux. 3. The optical path splitting optical element according to claim 1, wherein the reflecting surface is formed on each side surface of the polygonal pyramid, and the transmitting portion includes at least one side surface of the polygonal pyramid, An image pickup device, which is formed by deleting a vertical line drawn from an apex to a bottom face and a part surrounded by a surface passing through a hypotenuse of the side face. 4. The optical path splitting optical element according to claim 1 or 2, wherein the optical path splitting optical element is formed of a combination of triangular prisms, the reflecting surface is formed by one surface of each triangular prism, and a transmitting portion is formed in a portion where the triangular prism does not exist. An imaging device characterized by being formed. 5. The optical path splitting optical element according to claim 1 or 2, wherein the optical path splitting optical element is formed by a combination of flat plate mirrors, the reflective surface is formed by the reflective surface of each flat plate mirror, and the transmissive portion is formed at a portion where the flat plate mirror does not exist. The image pickup device is characterized by being formed.