JPH0237883A - Solid-state image pickup element - Google Patents

Abstract

PURPOSE:To effectively suppress a smear component by providing a second vertical transfer register and a second horizontal transfer register to transfer the smear component only. CONSTITUTION:A first vertical transfer register 41 to receive the transfer of a signal charge from a light receiving part 21 is arranged and formed along the light receiving part 21 in the same way as an interline transfer CCD and further, a second vertical transfer register 201 not to receive the transfer of the signal charge from a transfer gate 7 is arranged and formed along the light receiving part 21. Besides a first horizontal transfer register 8a in which the signal charge from first vertical transfer registers 41-4n is inputted in parallel and a second horizontal transfer register 8b to input a smear component to occur at second vertical transfer registers 201-20n in parallel and output successively in a horizontal direction is arranged and formed in parallel to the first horizontal transfer register 8a. Thus, by obtaining the difference between respective output signals, the smear component is cancelled and the video signal excluding the smear component is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a structure of a solid-state imaging device that can effectively reduce smear components.

"Prior Art" An interline transfer (IT) CCD shown in FIG. 2 can be cited as a representative example of a conventional solid-state image sensor (hereinafter referred to as CCD). Light-receiving cells l are arranged in a column direction on a single-chip semiconductor substrate to form a light-receiving section 2, 3.2°,
..., 2o are constructed. Each light receiving cell 1 generates a signal charge corresponding to the intensity of the received light. Light receiving section 2i (
Accumulation of charges generated in each light receiving cell 1 of i-1-n)
A vertical transfer register 42 having a transfer region 3 and transferring (shifting) the charges in the vertical direction is formed in the column direction along with the light receiving section 25. The signal charge generated in each light receiving cell 1 is transferred to the vertical transfer register 4. In order to transfer the light to the corresponding storage/transfer region 3, gate elements 5 are arranged along each column in correspondence with each light receiving cell l, and the gate elements in each column are connected to a gate control line 6. , the gate is controlled to open and close by a control signal given from the outside, and the light receiving cell 1
signal charges are transferred to the storage/transfer region 3. The gate elements 5 and gate control lines 6 in each column are collectively called a transfer gate 7.

In the light receiving section 2, the incident light is converted into a signal charge, and this signal charge is accumulated in each light receiving cell 1 for l frame period.
The data are transferred to the vertical transfer register 4 all at once during the vertical blanking period.

The signal charge shifted from each vertical transfer register 4 is input in parallel to the horizontal transfer register 8 every l horizontal scanning period, sequentially shifted in the horizontal direction, read out as a video signal, and outputted via the output amplifier 9. is supplied to terminal 210.

Even if the transfer gate 7 is off, a small amount of the signal charge present in the light receiving section 2 leaks to the vertical transfer register 4 side (referred to as a smear component) and is superimposed on the signal charge to be transferred, causing the reproduced image to become blurred. It has been known.

Another conventional example is frame interline transfer (F
The IT) CCD is shown in FIG. 3, with parts corresponding to those in FIG. 2 being given the same reference numerals. In this case, memory portions 1) 1 to 1) for storing signal charges for one screen are provided in series with the vertical transfer registers 41 to 41, respectively, and each vertical transfer register 4 and the memory portion 1) The smear component generated in 4 is transferred at high speed during the vertical blanking period and discharged to the outside via the horizontal transfer register 8. After that, the transfer gate 7 is turned on and the signal charge of the light receiving section 2 is transferred to the vertical transfer register 4. and is immediately transferred to the memory part 1) at high speed. These operations are performed during the vertical blanking period, and thereafter, signal charges for one row are read into the horizontal transfer register 8 every horizontal scanning period, and are sequentially read out in the horizontal direction at high speed to create a video signal.

"Problems to be Solved by the Invention" In conventional interline transfer CCDs, no fundamental measures have been taken to reduce smear components, and it is inevitable that images will become blurred due to smear components.

Furthermore, although the smear component is effectively reduced in the conventional frame interline transfer CCD, a high-speed transfer pulse is required to discharge the smear component from the vertical transfer register 4 and the memory part 1) during the vertical blanking period. ,
A high-speed transfer pulse is required to transfer the signal read to the vertical transfer register 4 to the memory part 1) during the vertical blanking period, and generally a complicated circuit is required to generate these high-speed transfer pulses. It was necessary.

An object of the present invention is to provide a new CCD that can effectively reduce smear components without using particularly high-speed transfer pulses unlike frame interline transfer CCDs.

"Means for Solving the Problem" According to the present invention, there are a plurality of light receiving sections each having a large number of light receiving cells arranged in a column direction, and charge accumulation and transfer corresponding to each light receiving cell of the light receiving section. A plurality of first vertical registers in which areas are arranged in a column direction and vertically transfer signal charges transferred from the light receiving parts and smear components leaking from the light receiving parts, and corresponding to each light receiving cell of the light receiving part. A plurality of second vertical registers are arranged in which charge storage/transfer regions are arranged in the column direction, and each of which vertically transfers the smear components leaking from the light receiving sections, and a signal charge generated in each light receiving cell of the light receiving section. The first above
a transfer gate that transfers to the vertical transfer register; a first horizontal transfer register that inputs signal charges including smear components transferred from the plurality of first vertical transfer registers in parallel and sequentially transfers them in the horizontal direction; The solid-state imaging device is provided with a second horizontal transfer register that inputs the smear components transferred from the second vertical transfer register in parallel and sequentially transfers them in the horizontal direction.

``Embodiment'' An embodiment of the present invention is shown in FIG. 1, where the same reference numerals are given to corresponding parts as in FIGS. 2 and 3, and some redundant explanations will be omitted.

A first vertical transfer register 4 that receives signal charges from the light receiving section 2 through the transfer gate 7. The light receiving section 2. is similar to the interline transfer COD (Fig. 2). However, in the present invention, second vertical transfer registers 20 . is the light receiving section 2. An array is formed along the The signal charge of the light receiving section 2□ leaks to the second vertical transfer register 20, and a smear component is generated.

First vertical transfer register 4. A first horizontal transfer register 8a that inputs signal charges (including a smear component) of 4, . ~
A second horizontal transfer register 8b, which inputs the smear components generated at 20n in parallel and sequentially outputs them in the horizontal direction, is arranged side by side with the first horizontal transfer register 8a. 1st. The charges output from the second horizontal transfer registers 8a, 8b are converted into current, voltage, or power by output amplifiers 9a, 9b, respectively, and are amplified and applied to output terminals 10a, 10b. By connecting these output terminals 10a and 10b to the input terminals of an external differential amplifier 21 and taking the difference between the respective output signals, the smear component is canceled out, and a video signal containing no smear component is obtained. Note that the differential amplifier 21 may be provided on the CCD chip side.

"Effects of the Invention" According to the present invention, a first vertical transfer register and a first horizontal transfer register similar to the conventional ones are provided for transferring signal charges including smear components, but in this invention, only smear components are transferred. A second vertical transfer register and a second horizontal transfer register are provided. Therefore, these first.
By taking the difference between the signals output from the second horizontal transfer register, the smear component can be effectively suppressed.

The present invention does not particularly require high-speed transfer pulses for reducing smear components as in the prior art, so it is possible to simplify the pulse generation circuit for driving the CCD.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a conventional interline transfer (IT) CCD, and FIG. 3 is a block diagram of a conventional frame interline transfer (IT) CCD.
T) It is a block diagram of COD. 3 mouths

Claims (1)

[Claims] (1) A plurality of light receiving sections in which a large number of light receiving cells are arranged in a column direction, and a charge accumulation/transfer region is arranged in a column direction corresponding to each light receiving cell in the light receiving section, and the light receiving section a plurality of first vertical registers that vertically transfer signal charges transferred from the light receiving section and smear components leaking from the light receiving section; A plurality of second vertical registers are arranged and vertically transfer smear components leaking from the light receiving sections, respectively, and a signal charge generated in each light receiving cell of the light receiving section is transferred to the first register.
a transfer gate that transfers to the vertical transfer register; a first horizontal transfer register that inputs signal charges including smear components transferred from the plurality of first vertical transfer registers in parallel and sequentially transfers them in the horizontal direction; A solid-state imaging device comprising a second horizontal transfer register that inputs smear components transferred from the second vertical transfer register in parallel and sequentially transfers them in the horizontal direction.