JPH03191678A - Image pickup device - Google Patents

Abstract

PURPOSE:To read the images with image resolution higher as much as the number of single solid state image pickup elements by dividing an optical image to reflect them and reading these divided optical images via plural solid state image pickup elements in s state where the optically different areas are set contiguous to each other. CONSTITUTION:An image pickup area is optically divided into four pieces in terms of a single screen area, and these divided image pickup areas are allocated to the read valid picture element parts of four solid state image pickup elements 2A-2D respectively and then read in a state where they are optically contiguous to each other. Then the elements 2A-2D are positioned at the reflected image forming positions secured via the reflecting surfaces 7A-7D. The sloping angles of surfaces 7A-7D are defined at 45 deg. to an optical axis, and a reflecting optical axis is orthogonal to the optical axis of an image pickup lens 5. Thus the photodetecting surfaces of the elements 2A-2D are set parallel to the optical axis of the lens 5 and arranged around a pyramidical prism mirror 6. As a result, the complicated image processing can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an imaging device used in, for example, an electronic camera or a TV camera.

Conventional technology In recent years, research and development has been progressing to improve the quality of this type of imaging device.
It is at the stage of practical application as an imaging method based on the V standard. According to this, the frequency band used is very high, such as a 20 to 30 MHz band.

In addition to increasing the resolution of such imaging methods, solid-state imaging devices are also being promoted. However, when considering a solid-state imaging device that can support the above-mentioned high-definition imaging method, it requires a number of pixels of 1 million or more and a clock frequency of 30 MHz or more. It is currently difficult to develop such a solid-state image sensor (by the way, the NIKKEI ELECTRO
NICS” (1988, 2, 22, N1441p96
), a prototype CCD type solid-state image sensor with 2 million pixels has been announced, but it has not yet reached the practical stage).

Therefore, methods to achieve higher definition using current solid-state image sensors and drive methods are being considered.
There is one as shown in Japanese Patent No. 212178. In this method, the light image obtained through the imaging lens is divided and reflected by a reflector placed at the pupil position of the optical system, for example, four reflective surfaces of a quadrangular pyramid, and each of the divided and reflected light images is reflected on each light-receiving surface. For example, four solid-state imaging devices are arranged so that images are formed at positions optically shifted from each other by a predetermined pitch. FIG. 10 is a diagram showing the optical arrangement relationship of the first to fourth four solid-state image sensors IA to ID according to the publication method. Considering the first image sensor IA as a reference, the second image sensor IB is shifted by a predetermined pitch PN in the horizontal direction, and the third image sensor IB is shifted by a predetermined pitch PN in the horizontal direction.
The fourth image sensor IC is shifted by a predetermined pitch PM in the vertical direction, and the fourth image sensor ID is shifted by a predetermined pitch PN in both the horizontal and vertical directions.

PM is off. Pitch deviation PN in this case.

PM is the same as the pixel shifting method shown in Japanese Patent Publication No. 56-40546, etc., in which the first to fourth image sensors IA to 10
The pixel arrangement pitch in the horizontal and vertical directions is an integer fraction of each pixel array pitch. By adopting such an optical arrangement, resolution in the horizontal and vertical directions is improved.

FIG. 11 shows the first to fourth image sensors IA to ID when shifted by l/2 pixel pitch in both the horizontal and vertical directions.
The arrangement relationship of each pixel in the figure is shown enlarged to the pixel order. In the figure, A represents each pixel of the first image sensor IA, ~, D
indicates each pixel of the fourth image sensor ID.

As a result, the number of pixels in the horizontal direction of the four image sensors is reduced to H2.
O2 and the number of pixels in the vertical direction is V2O3, the performance is equivalent to that of an image sensor with a total number of pixels on the order of 1.5 million and a horizontal resolution on the order of 1000 lines.

Problems to be Solved by the Invention However, when looking at the structure of a solid-state image sensor, as shown in FIG. 12, each pixel of each image sensor IA to ID is Not optically separated (not in the state shown in Figure 11),
Since all pixels partially overlap, it is not possible to obtain a high actual resolution.

In particular, in order to increase the area of the light receiving part and the transfer COD,
In the type with laminated amorphous Si photoelectric conversion strips (see the above-mentioned literature), depending on the size of the light receiving part,
Moreover, no substantial improvement in resolution can be expected.

Furthermore, it is not easy to accurately arrange the reflector at the pupil position of the optical system.

Means for Solving the Problems An imaging lens and a reflector having a plurality of reflective surfaces disposed on the optical axis of the imaging lens to divide and reflect a light image transmitted through the imaging lens are provided, and the reflector A plurality of solid-state imaging devices were arranged at optical positions where optically different imaging regions received light in a relatively adjacent state for each light image divided and reflected by the solid-state imaging device.

Each solid-state image sensor receives the light image that is divided and reflected by each reflecting surface of the action reflector. are optical positions that receive light in a relatively adjacent state, so by combining the read image signals of the reading area of each solid-state image sensor after reading, an image for one screen is reproduced.

Therefore, regardless of the size of the light-receiving section of the solid-state image sensor, it is possible to read with a resolution that is twice as high as the number of solid-state image sensors when reading with a single solid-state image sensor.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7.

First, this embodiment is an example in which four solid-state image sensors 2A to 2D are used to read an image for one screen, and FIG. 2 shows the relative optical arrangement of these solid-state image sensors 2A to 2D. Show relationships. Here, which solid-state image sensor 2A to 2D
The number of effective pixels for reading is 512 in the horizontal force direction (H) and 490 in the vertical direction (V), and in FIG. .

Moreover, arrow S in FIG. 2 indicates each solid-state image sensor 2A to 2.
The reading scanning direction of D is shown. Therefore, in this embodiment, the imaging area for one screen area is optically divided into four parts, and each imaging area is assigned to the effective reading pixel portion of the four solid-state image sensors 2A to 2D. They are arranged so that they can be read adjacent to each other.

FIG. 3 is a partially enlarged view of the vicinity of the connection portion 3 in which the arrangement relationship of each pixel (indicated by A to D) is expanded to the pixel order. For the effective pixel portion of the first image sensor 2A, the second image sensor 2B
The effective pixel portions of are adjacent to each other in the horizontal direction, and the end pixels are arranged at intervals corresponding to the horizontal pixel pitches P and I of the solid-state image sensor 2.

The effective pixel portion of the third image sensor 2C is the same as that of the first image sensor 2A.
The pixels are adjacent to each other in the vertical direction with respect to the effective pixel portion of the solid-state image sensor 2, and the end pixels are arranged at intervals corresponding to the vertical pixel pitch Pv of the solid-state image sensor 2. The effective pixel portion of the fourth image sensor 2D is horizontally and vertically adjacent to the effective pixel portions of the second and third image sensors 2B and 2G, and the end pixels of each other are adjacent to the effective pixel portions of the second and third image sensors 2B and 2G.
They are arranged at intervals corresponding to horizontal and vertical pixel pitches PM and Pv.

Therefore, for example, when using an EIA type solid-state image sensor 2, if the number of effective pixels to be read in the vertical direction is 490 as described above, the number of effective pixels in the vertical direction It is possible to read with twice as high resolution as several 980. Similarly, in the horizontal direction, it is doubled (=10
24 pixels) high resolution reading is possible. At this time, if a one-chip color image sensor is used as the solid-state image sensor 2, high-resolution color image reading becomes possible.

Note that since the connection part 3 only needs to be set at a level where it is not noticeable, a practical level of resolution can be obtained even if the adjacent pitch interval does not necessarily match the pixel pitches PM and PV exactly as shown in Fig. 3 (conventional method According to the above, it is necessary to set the optical pitch deviation between each solid-state image sensor to be less than the pixel pitch).

An imaging optical system that realizes such an optical arrangement of the four solid-state imaging devices 2A to 2D is configured, for example, as shown in FIG. 1. First, an imaging lens (zoom lens) 5 is provided that forms an optical image of light reflected from a subject (original) 4. A quadrangular pyramidal prism mirror 6 as a reflector whose apex is placed on the optical axis of the imaging lens 5 is provided downstream of the imaging lens 5 . That is,
The quadrangular pyramidal prism mirror 6 has reflective surfaces 7A to 7D formed of four triangular pyramidal surfaces, and reflects the light image corresponding to the subject 4 into four parts centered at the apex on each of the reflective surfaces 7A to 7D. . Here, each of the reflecting surfaces 7A to 7D of the quadrangular pyramid prism mirror 6 is connected to the subject 4 as illustrated in FIG.
The reflective surfaces 78 to 7D are arranged at an inclination angle of 45 inches relative to the optical axis.
It is formed as 5@. Each of the solid-state image sensors 2A is positioned at a reflection imaging position formed by these reflecting surfaces 78 to 7D.
~2D is provided. At this time, each reflective surface 7A to 7D
Since the inclination angle is 45'' with respect to the optical axis, the reflected optical axis is perpendicular to the optical axis of the imaging lens 5, and the solid-state imaging devices 2A to 2D
The light-receiving surface of the lens is parallel to the optical axis of the imaging lens 5, and the arrangement around the square pyramidal prism mirror 6 is facilitated. Also,
Since the divided light image is received by the quadrangular pyramid prism mirror 6 and becomes a rectangular area image, it can be read with a normal solid-state image sensor having a rectangular effective pixel portion, and no complicated image processing is required. At this time, each solid-state image sensor 2A to 2D
are arranged at positions where they receive only the light images reflected by the respective reflecting surfaces 7A to 7D, that is, the light images of different imaging areas obtained by dividing one screen area into 1/4 as explained in FIG. There is.

FIG. 4 schematically shows this situation. Now, it is assumed that the imaging areas obtained by dividing one screen into four are respectively EA-E.

Then, each of the reflecting surfaces 7A to 7D of the square pyramid prism mirror 6
reflects a light image corresponding to approximately each imaging area EA-ED. Therefore, the first solid-state image sensor 2A is arranged at a position where it receives light from the imaging area EA in the reflected light image from the reflecting surface 7A.

Further, the second solid-state image sensor 2B is arranged at a position where it receives light from the reflected light image in the imaging area E and later from the reflecting surface 7B. The third and fourth solid-state image sensors 2c, 2, and D are similarly arranged at the light image receiving positions of the imaging areas EC9ED of the reflective surfaces 7C and 7D, respectively.

FIG. 5 shows the arrangement of the first solid-state image sensor 2A more specifically, for example.

Now, the center of subject 4 is 0, and the corner point of imaging area EA is P.
and the diagonally adjacent imaging area E0 in the imaging area Japan
Assuming that an arbitrary point therein is Q, a part of the reflected light from the Q point is also reflected by the reflective surface 7A due to the characteristics of the imaging lens 5, and an image is formed on the Q' point. That is, the reflected light image of the subject 4 is not formed on the reflective surface 7A, and the optical information of each point is mixed. However, it is only necessary to arrange the corner points S of the effective pixel portions of the two solid-state imaging devices so that they coincide with the position corresponding to the apex 1 of the quadrangular pyramidal prism mirror 6 on the imaging plane. The same applies to elements 2B to 2D.

The image signals divided and read by each of these solid-state image sensors 2A to 2D pass through an analog signal processing section and are subjected to connection and synthesis processing in an image synthesis circuit, so that the entire image for one screen is read.

In other words, compared to the case where one screen of subject 4 is received by one solid-state image sensor 2, four solid-state image sensors 2A with the same performance are used.
By using ~2D and having an imaging area EA-Eo divided into four, the light is received while the imaging area is expanded four times, which is equivalent to one screen area. It can be read at twice the resolution. At this time, since each imaging area does not overlap at the pixel level, it is not affected by the size of the light receiving portion of each solid-state imaging device 2A to 2D.

FIGS. 6 and 7 show an example of the configuration of an image reading device using such an imaging device. A document (subject) 4 set on the document table 8 is illuminated by a fluorescent lamp 11 of an illumination device 1O attached to a support 9 provided at the end of the document table 8. This illumination device 10 can be moved up and down using the support 9 as a guide. In addition, a reflector 12 attached to the arm of the lighting device 10
The end portion of the illumination device 10 is rotatable with respect to the arm portion of the illumination device 10, and the end portion thereof is a fulcrum, so that the illuminance distribution on the document surface can be adjusted. A camera body (camera) 14 consisting of an imaging lens 5, a quadrangular pyramid prism mirror 6, an analog signal processing section 13, etc. is supported by a column 9 via a camera mounting section 15 so as to be movable up and down, and the imaging magnification can be adjusted. has been done.

Next, a second embodiment of the present invention will be described based on FIG. 8. The same parts as those shown in the previous embodiment are indicated using the same reference numerals. In this embodiment, four solid-state image sensors 2A to 2A are used.
This is an optical arrangement in which 2D effective reading pixel parts are partially overlapped at each other's connecting parts 3. In the figure, Δ indicates an overlapping part.

In this case, in order to avoid overlapping images at the overlapping area Δ during reading, when combining image signals, either all of one side of the overlapping area Δ or a part of both (in the illustrated example, the part indicated by the dashed line is the real one). The geometric continuity at the connection part 3 can be ensured by cutting off the pixel part (corresponding to the connection part 3) and relatively shifting and correcting the pixel part to be cut off as an image signal.

In other words, by partially overlappingly reading the connecting portions 3 of the optical arrangement of the solid-state image sensors 2A to 2D as in this embodiment,
Solid-state photography ftJ! Even if the edges of the effective reading pixel portions of the elements 2A to 2D are not precisely aligned, correction can be made pixel by pixel after reading.

In this case as well, each reflective surface 7A to 7 of the quadrangular pyramid prism mirror 6
This is the reception of a divided light image from D, and since it becomes a rectangular area image, it can be read with a normal solid-state image sensor having a rectangular effective pixel portion, and does not require complicated image processing.

Further, a third embodiment of the present invention will be explained with reference to FIG.

In this embodiment, a roof-type prism mirror 17 having two reflective surfaces 16A and 16B is used as a reflector, and the imaging area is divided into two, and the reflected light image of each area is transmitted to each solid-state image sensor 18.
The images are focused on A and 18B. In the figure, the ridge line with the apex angle of 90° of the roof-type prism mirror 15 is arranged on the optical axis of the imaging lens 5, and each reflective surface 16A, 1
6B is set at 45° with respect to this front axis. Also, 2
The light receiving surfaces of the two solid-state image sensors 18A and 18B are arranged parallel to the optical axis and the ridgeline.

Effects of the Invention The present invention divides and reflects a light image as described above, and uses a plurality of solid-state imaging devices to read optically different imaging areas in adjacent states. After reading, if the read image signals of the reading area of each solid-state image sensor are combined, an image for one screen can be reproduced.
Therefore, regardless of the size of the light-receiving part of the solid-state image sensor, it is possible to read with a resolution that is twice as high as the number of solid-state image sensors when reading with a single solid-state image sensor, and the reading effectiveness of each solid-state image sensor is Since the pixel parts are arranged so that they partially overlap at the connecting parts of their optical positions, easy correction can be made without having to precisely align the optical positions of the effective reading ends of each solid-state image sensor. Furthermore, since the reflector is a square pyramidal prism mirror, the split light image can be read using a general solid-state image sensor with a rectangular effective pixel area, and no particularly complex image processing is required. It is something.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of the present invention, and FIG.
The figure is a layout diagram showing the relative optical arrangement of the solid-state image sensor, Figure 3 is a layout diagram showing a part of it enlarged, and Figure 4 is a schematic diagram showing the state after reflection by a square pyramid prism mirror. 5 is an explanatory diagram schematically showing the state of reflection, and FIG. 6 is a front view of an image reading device to which this embodiment is applied.
FIG. 7 is a side view thereof, FIG. 8 is a layout diagram showing the relative optical arrangement of solid-state imaging devices showing a second embodiment of the present invention, and FIG. 9 is a third embodiment of the present invention. A schematic perspective view showing
Fig. 10 is a layout diagram showing the relative optical arrangement relationship of solid-state image pickup devices showing a conventional example, Fig. 11 is a layout diagram showing a part of the layout enlarged, and Fig. 12 is a practical layout diagram showing a further enlarged view. This is a layout diagram. 2A to 2D...solid-state image sensor, 3...connection section, 5.
...Imaging lens, 6... Square pyramid prism mirror (reflector), 7A to 7D... Reflective surface, 16A, 16B...
Reflective surface, 17...Reflector, 18A, 18B...Amount of solid-state image sensor Applicant: Ricoh Co., Ltd. Nippon Telegraph and Telephone Corporation "UnU planning - military map, %, JO diagram yD, 72 diagram prisoner l prisoner round round round round round round round prisoner round prisoner round round prisoner round round round prisoner round prisoner

Claims (1)

[Scope of Claims] 1. An imaging lens, a reflector disposed on the optical axis of the imaging lens and having a plurality of reflective surfaces that divide and reflect the light image transmitted through the imaging lens, and a reflector that divides the light image by the reflector. 1. An imaging device comprising a plurality of solid-state imaging devices arranged at optical positions where optically different imaging areas are relatively adjacent to each other and receive reflected light images. 2. The image pickup device according to claim 1, wherein the effective reading pixel portions of the solid-state image pickup devices are arranged so as to partially overlap each other at the connection portions in their respective optical positions. 3. The imaging device according to claim 1 or 2, wherein the reflector is a square pyramidal prism mirror.