JPS62186218A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve the resolution of an image by rotating a transparent parallel plate obliquely intersecting with the optical axis of a photographing optical system around the optical axis, detecting an output of a photodetecting element synchronously with the rotation and using plural areas as respective picture elements to form an image signal. CONSTITUTION:The parallel plate 1 is arranged in a drum 11 and the drum 11 is rotated around the center axis coincident with the optical axis of the photographing optical system 2 by a motor 12. The phase of the parallel plate 1 is detected and synchronized with a control pulse for a signal detecting circuit 4 or the like by a synchronizing signal. The titled device is constituted so that four picture elements of an image to be picked up are detected by respective elements in a two-dimensional photodetecting element array 2, e.g. an upper left picture element (a), a lower left picture element (b), a lower light picture element (c) and an upper right picture element (d) are successively detected by respective photodetecting elements. Signals read out from a signal detecting circuit 4 are time-sequentially multiplexed in respective picture elements (a)-(d), and after A/D conversion, respective picture elements (a)-(d) are temporarily stored in respective frame memories 6a-6d and then read out in the order of picture element array of the image to be picked up.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a solid-state imaging device in which a transparent parallel plane plate obliquely intersecting the optical axis of an imaging optical system is rotated around the optical axis and synchronized with the rotation. By detecting the output of the photodetecting element, multiple areas of the image to be captured are detected by a common photodetecting element, and an image signal is formed using each of the multiple areas as a pixel, thereby increasing the number of pixels of the image signal. This increases the number of pixels in the photodetecting element array to achieve improved resolution.

[Industrial application field]

The present invention relates to a solid-state imaging device, particularly a solid-state image sensor in which the pixel density of the image signal is effectively higher than the density of the photodetecting element.
Concerning improvements in imaging equipment.

In order to improve the resolution of image signals of solid-state imaging devices, efforts are being made to increase the pixel density of the image signals. If a means for effectively increasing the density higher than that of the photodetector array can be realized, a significant effect in improving the resolution can be obtained.

[Conventional technology]

Semiconductor photodetecting elements include photovoltaic type, which has a pn junction and generates electromotive force according to incident light, photoconductive type, whose electric resistance changes according to incident light, and photoconductive type, which has a pn junction and generates electromotive force according to incident light, and photoconductive type, which has a pn junction and generates electromotive force according to incident light. Although there is the old S type in which carriers are accumulated in response to light, solid-state imaging devices usually have photodetecting elements arranged in a two-dimensional array.

An image of the object to be imaged is formed by the imaging optical system on the light-receiving surface of this two-dimensional photodetecting element array, and an electrical signal corresponding to the incident light is obtained from each photodetecting element.
D), the image signal is transferred and sequentially detected to form a time-series multiplexed image signal.

Since a means for accumulating and transferring charges is required in this way, the light-receiving area of the photodetecting element is greatly limited, and the ratio to the pixel area when the imaging plane is divided into equal parts in a matrix is, for example, 25.
It remains at around %.

[Problem that the invention seeks to solve]

In order to improve the resolution of image signals, progress is being made to increase the element density of photodetector arrays by pattern reduction, and to improve the charge storage and transfer means for this purpose. This is not desirable in terms of securing volume, and there are many restrictions on the ability to significantly increase density using this method.

In view of this situation, an object of the present invention is to significantly improve image resolution by effectively increasing the pixel density of image signals over the density of photodetecting elements.

[Means for solving problems]

The above problem can be solved by rotating a transparent plane-parallel plate obliquely intersecting the optical axis of the imaging optical system around the optical axis and detecting the output of the photodetecting element in synchronization with the rotation. This problem is solved by the solid-state imaging device according to the present invention, which detects a plurality of regions using a common photodetecting element, and forms an image signal using each of the plurality of regions as pixels.

[For production]

FIG. 1 is a schematic diagram showing a solid-state imaging device according to the present invention. In the same figure (al is a schematic diagram showing the structure of the imaging section, 2 is the most image optical system, 3 is a two-dimensional photodetecting element array, 1
is a transparent parallel plane plate that rotates obliquely to the optical axis of the imaging optical system 2. Also in the same figure (bl is a partial schematic plan view of the two-dimensional photodetecting element array 3, 3A, 3B, 30, etc. shown with diagonal lines are each photodetecting element, 3Aa, 3Ab, 3A shown with broken lines)
c, 3Ad, etc. indicate pixels of the image to be imaged when the parallel plane plate 1 is not provided.

In this way, if the light beam is obliquely incident on the parallel plane plate l, the output light will shift parallel to the incident light, so that, for example, the pixel 3Aa of the image to be imaged can be made to be incident on the photodetector element 3A, If the parallel plane plate 1 is rotated around the optical axis, for example, the number of pixels of the imaging target image incident on the photodetecting element 3A is 3.
Move sequentially as A a -3^b = 3 A c -3 A d.

Therefore, if the output of the photodetecting element 3A is detected in synchronization with the rotation of the parallel plane plate 1, the areas 3Aa, 3^b,
Electrical signals corresponding to 3Ac and 3Ad are obtained one after another.

〔Example〕

The present invention will be specifically explained below using examples.

FIG. 2 is a schematic diagram showing an embodiment of the present invention, in which 1 is a parallel plane plate, 11 is a drum, 12 is a motor, 13 is a synchronizing signal generation circuit, 2 is an imaging optical system, and 3 is a two-dimensional photodetecting element. 4 is a signal detection circuit, 5 is an analog/digital converter, and 6a, 6b, 6c, and 6d are frame memories.

In this embodiment, the parallel plane plate l is mounted inside the drum l,
This drum 11 is rotated by a motor 12 around its central axis which coincides with the optical axis of the imaging optical system 2. The phase of the parallel plane plate 1 (drum 11) is detected, for example, by an optical method, and is synchronized with a control pulse of a signal detection circuit 4 or the like made of a CCD or the like using a synchronization signal.

In this embodiment, as shown in FIG. 1(b), each element of the two-dimensional photodetecting element array 3 detects four pixels of the image to be imaged. Each pixel a on the upper left, each pixel b on the lower left, each pixel C1 on the lower right, and each pixel d on the upper right are sequentially detected.

The signals read out from the signal detection circuit 4 are from pixels a, b, .
It is time-series multiplexed for each C% d, and after analog/digital conversion, each pixel as B, C, and d is stored in the frame memories 6a, 6b, 6c, and 6d and read out in the order of pixel arrangement of the image to be captured. . The subsequent signal processing may be similar to the conventional method.

The material of the parallel plane plate 1, dimensions such as thickness, angle of inclination with respect to the optical axis, etc. are selected and set depending on the purpose.
Sapphire (A120
3), the refractive index n = 1.76 and Figure 3 (a
The thickness d shown in l, the shift of the emitted light with respect to the incident angle α
r is the value illustrated in the same figure (b), which is several 10 to 100-
A shift amount of approximately 100% can be easily achieved.

As is clear from the above description, this embodiment has the effect of increasing the number of pixels of the image signal to four times the number of pixels of the photodetector array. Furthermore, an area approximately three times larger than the light-receiving area of each photodetecting element can be used for a CCD, etc., and a device with sufficient margin for the amount of transferred charge can be easily realized.

Note that in the above embodiment, four pixels of the image to be captured are detected by one photodetecting element, but this correspondence can be selected in various ways depending on the purpose.

〔Effect of the invention〕

As explained above, according to the present invention, the effect of greatly increasing the number of pixels of an image signal compared to the number of pixels of a photodetecting element array can be obtained, and the resolution can be dramatically improved by high-density image signals. It becomes possible.

Moreover, sufficient margin is provided for pattern formation of the photodetecting element array, making it easy to realize the effects in a wide range of application fields such as visible light imaging and long-wavelength infrared region thermography.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a solid-state imaging device according to the present invention, and FIG.
1) is a schematic diagram showing the structure of the imaging unit, 1) is a partial schematic plan view of the photodetecting element array, FIG. 2 is a schematic diagram of an embodiment of the present invention, and FIGS. 3(a) and (b) FIG. 2 is a diagram showing an example of the amount of shift of emitted light by a parallel plane plate. In the figure, 1 is a rotating parallel plane plate, 2 is an imaging optical system, 3 is a two-dimensional photodetecting element array, 38, 3B, 30, etc. are each photodetecting element, 3^a, 3Ab, 3Ac, 3Ad, etc. are Pixels of the image to be captured; 4 is a signal detection circuit; 5 is an analog/digital converter; 6a, 6b, 6c, and 6d are frame memories; 11
12 is the drum, 12 is the motor, and 3 is the synchronous signal generation circuit.

Claims (1)

[Claims] By rotating a transparent parallel plane plate obliquely intersecting the optical axis of the imaging optical system around the optical axis and detecting the output of the photodetecting element in synchronization with the rotation, multiple regions of the image to be imaged can be detected. A solid-state imaging device characterized in that detection is performed using a common photodetecting element, and an image signal is formed using each of the plurality of regions as a pixel.