Solid-state image pickup device and method for driving the same

Abstract

In a solid-state image pickup device, third transfer electrodes are disposed in parallel to vertical transfer registers, and second transfer electrodes are disposed vertically to the vertical transfer registers. These transfer electrodes are also formed on the read-out gate portions to supply a driving voltage for reading out signal charges from photoelectric conversion elements. On the basis of the driving voltage applied to both the third and second transfer electrodes, the read-out of the signal charges to the vertical transfer registers is carried out. At the portion where the read-out of the signal charges is carried out, the transfer electrode at the read-out gate portion side and the sensor area of the photoelectric conversion element are formed so as to be adjacent to each other. At the portion where no read-out of signal charges is carried out, an offset area is provided between the transfer electrode at the read-out gate portion side and the sensor area of the photoelectric conversion element.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a solid-state image pickup device having photoelectric conversion elements (sensors) which are arranged two-dimensionally, such as a CCD solid-state image pickup device, and a method of driving the solid-state image pickup device. [0003] 2. Description of the Related Art [0004] In order to enhance the dynamic range in an image sensor using a CCD solid-state image pickup device (hereinafter referred to as “CCD image sensor”), there have been proposed various methods of picking up images with photoelectric conversion elements which are different in sensitivity and then composing these pickup images into an image. [0005] According to a first method of these methods, incident light is optically split to plural optical axes which are different in transmittance, and then the light beams thus split are detected by plural CCD image sensors arranged on the respective optical axes (see Japanes...

AI Technical Summary

Benefits of technology

[0015] In order to solve the above problems, an object of the present invention is to provide a solid-state image pickup device that brings flexibility to the spatial pattern design of the sensitivity of each photoelectric conversion element, has a broad dynamic range and a high dynamic resolution and is suitable in structure for further microstructure, and a method of driving the solid-state image pickup device.

Problems solved by technology

The first method needs plural CCD image sensors and a complicated optical system for splitting light, and thus has a problem that the manufacturing cost and the scale of the apparatus are increased.

According to the second method, information (image) detected with different sensitivity is achieved at a different time and for a different sub exposure time, so that it is difficult to accurately pick up the images of a moving subject and the resolution to a moving subject (hereinafter referred to as “dynamic resolution”) cannot be enhanced.

Further, the third method can solve the problems of the first and second methods, that is, both the problem that the apparatus is complicated and the problem that the dynamic resolution cannot be enhanced.

However, in the third method, the filters different in transmittance must be covered on the photoelectric conversion elements to perform sensitivity control, and thus the sensitivity of each photoelectric conversion element is fixed in the manufacturing process of the CCD image sensor, so that the sensitivity cannot be variably controlled.

Therefore, it is difficult to variably control the enlarging rate of the dynamic range in accordance with the condition.

However, as in the case of the method of covering the photoelectric conversion elements with the filters, the third method has a problem that the degree of freedom for the design of a spatial pattern of sensitivity is low, and for example it has a problem that signals having plural kinds of exposure times such as three or more kinds cannot be achieved in the vertical direction.

Therefore, the dynamic resolution cannot be enhanced like the second method.

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