JPS62188571A - Driving method for solid-state image pickup device - Google Patents

Abstract

PURPOSE:To constantly obtain a proper output even when there is no automatic iris function in a lens by adjusting the storage time of a signal charge according to the strength of the light received by the light receiving part of a solid-state image pickup element. CONSTITUTION:At the time of t=t1, a phir pulse is impressed to a reading gate 5, a signal charge is read from a photodiode 3 and the transfer is started in a storage part 2 through a vertical transfer part 4 by the phiv pulse. During the period of t=t2, the dummy charge of a photodiode 3 during the period of t=t2 is stored, the dummy charge stored at the time of t=t3 is read and the signal charge is stored during the period of t=t4. Then, at the time of t=t5, the dummy charge is transferred and discharged externally, at the time of t=t6, phir is impressed, and the signal charge of the final time stored in the storage part 2 is read and outputted. The time of t4 is changed so as to be the same quantity of light according to the strength of the light, thereby the same effect as an automatic diaphragm is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for driving a solid-state imaging device used in a video camera or the like, and specifically relates to a method for driving a solid-state imaging device.

(Prior Art) In recent years, the development of solid-state image sensors has progressed and their performance has improved.

When constructing a video camera using such a solid-state image sensor, a lens is used that has an auto-iris function that adjusts the amount of aperture depending on the intensity of light incident from the lens.

(Problems to be solved by the invention) However, lenses equipped with an auto iris function,
There is a problem in that it is not only large and expensive, but also takes time to set the aperture amount.

The present invention solves the above problems and provides a method for driving a solid-state imaging device in which the solid-state imaging device itself has an aperture function.

(Means for Solving the Problems) In order to solve the above problems, the present invention divides one cycle of signal accumulation time into multiple times, and reads out charges other than signal charges within horizontal blanking. The charge accumulated in the final cycle is treated as a signal charge, and the signal charge accumulation time in the final cycle is set to a time corresponding to the intensity of light received by the light receiving section.

(Function) With the above configuration, the signal charge accumulation time is adjusted depending on the strength of the light received by the light receiving section of the solid-state image sensor, so even if the lens does not have an auto iris function, the appropriate output is always achieved. can get.

(Example) Embodiments of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows an FIT type solid-state imaging device (Frame-Interlins Transfer) to which the driving method according to the present invention is applied.
nsferCarge-Coupled Device
) is a schematic diagram. (For example, K, l1orii e
t,al IEEE Transactions
on Electron Davisas, Vol.
ED, No. 7 July, 1984. ) In the figure, the solid-state imaging device consists of a light receiving section 1 that receives an optical signal, and a storage section 2 that temporarily stores signal charges obtained by converting the optical signal. A diode 3 is formed, a vertical transfer section 4 is formed that transfers the signal charge converted by the photodiode 3 in each column to the storage section 2, and a plurality of readout sections are further formed to read out the signal charge of the photodiode 3 in each column. A gate 5 is provided.

FIG. 2 is a drive pulse waveform diagram of the method for driving a solid-state imaging device according to the present invention. The waveforms C and BLK at the top are blanking pulses, and the L0 level is the video period. φ,
is a read pulse applied to the read gate 5, and φ7 is a transfer pulse applied to the vertical transfer section 4.

A method for driving the solid-state imaging device configured as described above will be described. First, when 1=11, read gate 5
A pulse φ is applied to the photodiode 3, and the signal charge is read out from the photodiode 3.

The pulse starts the transfer to the storage section 2 through the vertical transfer section 4. 1=1. During the period , dummy charges of the photodiode 3 are accumulated. The dummy charges accumulated at the time point j=t3 are read out, and the signal charges are accumulated for the next period of 1=14. Next, 1=1. At the point in time, the dummy charge is transferred and discarded to the outside, and 1=1. At the point in time, φ is applied and the last signal charge accumulated in the accumulation section 2 is read out and output.

The same effect as automatic aperture can be obtained by changing the above-mentioned time t4 depending on the strength of the light so that the amount of light is the same. Furthermore, by reading out the dummy charges during horizontal blanking, automatic aperture can be performed without generating a fixed pattern.

(Effects of the Invention) As explained above, according to the present invention, by adjusting the signal accumulation time depending on the strength of light, it is possible to provide the solid-state image sensor itself with an automatic aperture function, which eliminates the need for an aperture device. An inexpensive and compact video camera using an inexpensive lens can be obtained.

Furthermore, since the dummy charges are read out during horizontal blanking, a beautiful image can be obtained without generating a fixed pattern.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a solid-state imaging device to which a driving method according to the present invention is applied, and FIG. 2 is a diagram of its driving pulse waveform. DESCRIPTION OF SYMBOLS 1... Light receiving part, 2... Accumulation part, 3... Photodiode, 4... Vertical transfer part, 5... Read gate, C, BLK... Blanking pulse, φ
,...Read pulse, φ,...Transfer pulse.

Claims (4)

[Claims] (1) A light-receiving section in which light-receiving elements are arranged in a two-dimensional manner, a transfer section that transfers the signal charges of the light-receiving elements, an accumulation section that accumulates the transferred signal charges, and the accumulated signal charges. What is claimed is: 1. A driving method for a solid-state imaging device comprising: an output section for outputting a signal, the method comprising dividing a signal accumulation time into a plurality of times during one cycle. (2) Driving the solid-state imaging device according to claim (1), characterized in that among the signal charges that are divided and accumulated in multiple times, only the signal charges accumulated in the last time are treated as signal charges. Method. (3) The solid-state imaging device according to claim (2), wherein the final signal charge accumulation time is set to a predetermined time depending on the intensity of light received by the light receiving section. Driving method. (4) The method for driving a solid-state imaging device according to claim (1), wherein charges other than the signal charges accumulated in the final cycle are read out during horizontal blanking.