JPH0242879A - Solid-state image pick-up element and its driving method - Google Patents

Abstract

PURPOSE:To obtain an image with a small distortion even at the time of photographing a moving subject by forming the transfer electrodes of respective horizontal CCD shift registers to compose a horizontal CCD shift register group so as to be mutually independent for the horizontal CCD shift registers. CONSTITUTION:For a solid image pick-up element, photoelectric converting areas 1 are arranged in horizontal and vertical directions, and horizontal CCD shift registers 2 to be commonly provided corresponding to the areas 1 on horizontal lines to be common, respectively, and a vertical CCD shift register 3 provided commonly to the registers 2 are provided. The registers 2 to compose the horizontal CCD shift register group are the shift registers to be independently driven, namely, the shift registers in which the transfer electrodes of respective horizontal shift registers are formed independently for respective horizontal CCD shift registers, respectively, and they are connected to a horizontal CCD shift register scanning circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CCD solid-state image pickup device in which a large number of photoelectric conversion regions and means for extracting signals from each region are integrated on a semiconductor substrate, and a method for driving the same.

[Conventional technology]

In a conventional horizontal interline transfer CCD solid-state image sensor, a transfer section that transfers signal charges photoelectrically converted by two-dimensionally arranged photoconversion areas to the outside is a horizontal CCD shift register adjacent to the photoelectric conversion areas. and a vertical CCD shift register connected to one end of the shift register group, - for each horizontal scan, only the horizontal column of the photoelectric conversion area corresponding to the horizontal scan is transferred to the horizontal CCD shift register adjacent to the photoelectric conversion area; is being transferred to.

[Problem to be solved by the invention]

In conventional horizontal interline transfer CCD solid-state imaging devices, the signal charge accumulation period is shifted for each horizontal scanning line, that is, the imaging period is different for each horizontal scanning line, so that the subject is When a velocity component is included, there is a problem that the horizontal position of the subject differs between horizontal scanning lines, causing distortion in the overall captured image of the moving subject.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state image sensor and a method for driving the same that suppress distortion of a captured image of a moving subject.

[Means to solve the problem]

The gist of the means provided by the first invention of the present application is that the transfer electrode of the shift register (in each horizontal CC constituting a group of horizontal CCD shift registers adjacent to photoelectric conversion regions arranged in a two-dimensional manner) is connected to each horizontal CCD shift register. Each resistor is formed independently, and each horizontal CCD shift register can be driven independently.

Means provided by another invention of the present application is a method for driving an image of a solid-state image sensor according to the first invention of the present application, which includes three commonly used methods for driving a solid-state image sensor, namely: (a)- A driving method in which the order in which No. 42 charges in two horizontal rows of photoelectric conversion regions arranged in rows constitute two consecutive horizontal scanning lines in 2:1 interlaced scanning (or interlaced scanning) (in this case,) A horizontal scanning line signal is composed of signal charges of one horizontal column of photoelectric conversion regions.

(b) 2 lines of continuous photoelectric conversion area = (a driving method in which one row of Shingei charges constitutes two consecutive horizontal scanning lines in the scanning order in non-interlaced scanning (in this case, 1
(The signal between horizontal scanning lines is composed of signal charges of one horizontal column of photoelectric conversion regions).

(C) Four spatially continuous horizontal rows of photoelectric conversion regions are arranged in order: the first horizontal row of photoelectric conversion regions, the second horizontal row of photoelectric conversion regions, the third horizontal row of photoelectric conversion regions, and the fourth horizontal row of photoelectric conversion regions. A horizontal row of photoelectric conversion areas. In 2:1 interlaced scanning (or interlaced scanning), the parallel sum of signal charges in the horizontal row of the first photoelectric conversion area and the horizontal row of the second photoelectric conversion area constitutes one horizontal scanning line. , a driving method in which the parallel sum of signal charges of a horizontal row of third photoelectric conversion regions and a horizontal row of fourth photoelectric conversion regions constitutes one horizontal scanning line scanned next to the one horizontal scanning line. In the cases of (a) and (b), (1) The signal charges are transferred from the photoelectric conversion region to the horizontal CCD shift register group all at once.

<2) Driving the vertical CCD shift register and each horizontal CCD shift register at a speed synchronized with the scanning speed of the horizontal scanning line, (3) two horizontal rows of photoelectric conversion areas in case (a), and (c) Between each two horizontal rows of the first horizontal row of photoelectric conversion regions and the third horizontal row of photoelectric conversion regions, and the horizontal row of the second photoelectric conversion regions and the fourth horizontal row of photoelectric conversion regions in the case of The interval between the horizontal transfer start times at which the driving of the corresponding horizontal CCD shift registers is started is determined by: ■If the scanning order of the horizontal scanning line group is in the same direction as the transfer direction of the vertical CCD shift register, then it is 1 horizontal. During the scanning period, from the position in the vertical CCD shift register corresponding to the horizontal scanning line to be scanned first among the two horizontal columns to the vertical CC corresponding to the horizontal scanning line to be scanned next among the two horizontal columns.
Add the time required for the vertical CCD shift register to transfer the signal to the position in the D shift reno star,
■If the scanning order of the horizontal scanning line group is in the opposite direction to the transfer direction of the vertical CCD and -foot registers, from one horizontal scanning period each corresponds to the horizontal column of the horizontal scanning line to be scanned later of the two horizontal columns. Vertical CCI) The time required for a vertical CCD shift register to transfer a signal from a position in the shift register to a position in the vertical CCD shift register corresponding to the horizontal column of the horizontal scanning line to be scanned first of the two horizontal columns. The time will be deducted.

In the case of (c), in addition to the above <1) to (3), <4> the first horizontal row of photoelectric conversion regions or the third The horizontal transfer start time of the horizontal row of the photoelectric conversion area is relative to the horizontal transfer start time of the horizontal row of the second photoelectric conversion area and the horizontal line of the fourth photoelectric conversion area, ■The scanning order of the horizontal scanning line group is in the same direction as the transfer direction of the vertical CCD shift register, between the positions in each vertical CCD shift register corresponding to the horizontal column of the first photoelectric conversion area and the horizontal column of the second photoelectric conversion area, or between the positions of the third photoelectric conversion area. ■Horizontal scanning line group preceded by the time required for the vertical CCD shift register to transfer signals between the positions in each vertical CCD shift register corresponding to the horizontal row of photoelectric conversion regions and the horizontal row of the fourth photoelectric conversion region; The structure is characterized in that when the scanning order is opposite to the transfer direction of the vertical CCD shift register, there is a delay by the corresponding time.

[Effect]

The signal charge accumulation period in the photoelectric conversion region is from the time when the signal charge is transferred from the photoelectric conversion region to the horizontal CCD shift register until the next time of the transfer.

In conventional horizontal interline transfer CCD solid-state imaging devices, the signal charge accumulation period is shifted for each horizontal scanning line, that is, the imaging period is different for each horizontal scanning line, so that the subject is If the object has a velocity component, the horizontal position of the object differs between horizontal scanning lines, causing distortion in the overall captured image of the moving object. In contrast, in the present invention, the signal charges are transferred from the photoelectric conversion area to the horizontal CCD shift register group at the same time, so that the signal charges are accumulated in all the photoelectric conversion areas in the same period, unlike the conventional method. Distortion of captured images of moving objects does not occur. Since the signal charge transferred to the water-cell CCD shift register group can be driven independently from each horizontal CCD shift register,
The horizontal CCD shift register corresponding to one horizontal scanning line among the horizontal CCD shift register group and the vertical CCD shift register are driven at a speed synchronized with the scanning speed of the horizontal scanning line, and the data is stored in the horizontal CCD shift register. The signal charges are transferred to the vertical CCD shift register and output.

The most commonly used scanning method is one in which the scanning order is two consecutive horizontal scanning lines with every other horizontal scanning line; There is a field accumulation mode interlaced scanning method in which one horizontal scanning line signal is formed from parallel phases of two adjacent horizontal rows of signals in the photoelectric conversion area. There is a non-ink-race scanning method as a method in which two consecutive horizontal scanning lines are formed from two consecutive horizontal rows in the scanning order. The frame accumulation mode interlaced scanning scheme is formed from spatially consecutive first, second, third, and fourth horizontal columns. One horizontal scanning line flaw signal is formed from one horizontal row of signals in the photoelectric conversion area.In the case of (a) mentioned in the section for solving the above problem, when the field accumulation mode/interlaced scanning method is used, non-interlaced scanning is used. In the case of the above-mentioned method described in the section ``Means for Solving the Problems'', a frame MrR mode in which one horizontal scanning line signal is formed from the parallel sum of signals of two adjacent horizontal columns of the photoelectric conversion area is used. The interlaced scanning method corresponds to the case (c) described in the section for solving the above problem.

The characteristic points (2) shown above in the means for solving the problems
), (3) allows signals having the same accumulation time to be extracted from each photoelectric conversion area in the same time series format as a normal television video signal. That is, by correcting the transfer time difference between each horizontal scanning line signal that occurs in the vertical CCD shift register until each horizontal scanning line signal reaches the output section, horizontal scanning of the same length as the video signal required by the television side is achieved. It can be a line signal period and a horizontal blanking period.

Furthermore, in the frame accumulation mode/interlaced scanning method, the characteristic point (4) shown in the means for solving the problem
When the signals of the photoelectric conversion regions of two adjacent horizontal columns forming one horizontal scanning period are added in the vertical CCD shift register, the horizontal positions of the two horizontal columns are matched and the signals are added in parallel. Can be added.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of a solid-state imaging device using a horizontal interline transfer method to which the first invention is applied. This solid-state image sensor has photoelectric conversion regions 1 arranged in the horizontal and vertical directions, and a horizontal CCD shift register 2 provided in common corresponding to the photoelectric conversion regions 1 on a common horizontal line, and each horizontal CCD shift register A vertical CCD shift register 3 is provided in common with the register 2 . Each horizontal CC constituting the horizontal CCD shift register group
The D shift register 2 is a shift register that can be driven independently, that is, the transfer electrodes (
(not shown) is a shift register in which each horizontal CCD is formed independently for each shift register, and the horizontal CCD
It is connected to the shift register scanning circuit 4. The transfer electrodes of the CCD shift registers 2 and 3 are omitted in the drawing.

FIG. 2 is a schematic diagram of a conventional example shown in Japanese Patent Application No. 61-251191. In this solid-state image sensor, photoelectric conversion regions 21 are arranged in the horizontal and vertical directions, and a horizontal CCD shift register 22 and a horizontal CCD shift register 22 provided in common correspond to the photoelectric conversion regions 21 on a common horizontal line.
Vertical CC provided in common to the shift register 22
A D shift register 23 is provided. A transfer gate electrode 24 is provided on the transfer gate region between the photoelectric conversion region 21 on a common horizontal line and the horizontal CCD shift register 22 commonly provided corresponding thereto.
A horizontal/vertical transfer gate electrode 25 is provided on the region between the horizontal CCD shift register 22 and the vertical CCD shift register 23.
A transfer gate electrode 24 and a horizontal/vertical transfer gate electrode 25 are connected to a transfer gate electrode scanning circuit 26 and a horizontal/vertical transfer gate electrode scanning circuit 27, respectively. Transfer electrodes (not shown) of each horizontal CqD shift register 22 are formed in common for all horizontal CCD shift registers. The transfer electrodes of the CCD shift registers 22 and 23 are omitted in the drawing.

In the conventional example, a transfer gate electrode 24, a horizontal/vertical transfer gate electrode 25, a transfer gate electrode scanning circuit 2
6. Using the horizontal/vertical transfer gate electrode scanning circuit 27, 1
For each horizontal scanning line, a photoelectric conversion area 2 corresponding to the horizontal scanning line
1 signal was transferred to the horizontal CCD shift register 22 and outputted through the vertical CCD shift register 23. In this conventional example, the signal charge accumulation period is shifted for each horizontal scanning line, and there is a problem in that when a moving subject is photographed, the image is distorted. In contrast, in the present invention, since the signal charges are transferred from the photoelectric conversion area 1 to the horizontal CCD shift register 2 at the same time, the signal charges are accumulated in all the photoelectric conversion areas in the same period, and it is possible to photograph a moving subject. It is possible to obtain images with little distortion even when

FIG. 3 is a partial view of FIG. 1 for explaining the driving method of the present invention. In the example shown in FIG. 3, the horizontal CCD shift register 2 and the vertical CCD shift register 3 are two-phase driven, and the
The vertical CCD shift register and each horizontal CCD shift register are driven by the two clock pulses φ2 and φ2 at a speed synchronized with the scanning speed of the horizontal scanning line. FIG. 4 is a time chart showing the driving method after transfer from the photoelectric conversion area 1 to the horizontal CCD shift register 2 in an embodiment in the case of field accumulation mode/interlaced scanning method.
TH, ToB, and Tv are the horizontal scanning period, the horizontal blanking period, and the period in which the vertical CCD shift register moves between the positions in each vertical CCD shift register corresponding to the nth row and (n-)-2)th horizontal column, respectively. The time required to transfer the signal, and j n + j n+2, is the nth row, respectively.
2) This is the driving start time of the horizontal CCD shift register corresponding to the horizontal column of the row. Also, Figures 5(a) to (d)
4 schematically shows the signal transfer state at each time point (1) to (2) in FIG. As mentioned in feature point (3) shown in the means to solve the problem, the nth line and (n+2)
By setting the drive start time interval of the horizontal CCD shift register corresponding to the horizontal column of the row to (TH+TV), the horizontal scanning signal of the (n+2)th row becomes I] as shown in FIG. 5(d). TH from the beginning of the horizontal scanning signal of the row
Continuing with the horizontal blanking period that ends after the time , the period of the horizontal scanning signal is TH.

FIG. 6 is a time chart showing a driving method in an embodiment of the frame accumulation mode/interlaced scanning method according to the second invention. In addition, FIGS. 7(a) to (c) show the sixth
This figure schematically shows the signal transfer state at each time point (■) to (■) in the figure. As mentioned in the characteristic point (4) shown in the means for solving the problem, the driving start time of the horizontal CCD shift register in the nth row is set to and each vertical C corresponding to the (n+1)th horizontal column
By leading the positions in the CD shift register by the time required for the vertical CCD shift register to transfer the signal (in this example, one period of clock pulse φ1 or φ2), one horizontal When adding the signals of the photoelectric conversion regions of the two horizontal columns of the n-th row and the (n+1) row that form the scanning signal in the vertical CCD shift register, the two
It is possible to match the horizontal positions of the horizontal columns and add them in parallel (FIGS. 7(b) and 7(C)).

〔Effect of the invention〕

According to the solid-state image sensor and its driving method of the present invention as described above, when a moving subject is photographed, the image is not distorted.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a solid-state image sensor using a horizontal interline transfer method to which the first invention of the present invention is applied, FIG. 2 is a schematic diagram of a solid-state image sensor using a conventional horizontal interline transfer method, and FIG. , a partial diagram of FIG. 1 for detailed explanation of the invention of the driving method of the present invention, FIG. 4 is a time chart when the present invention is applied to field accumulation mode 1 to interlaced scanning method, and FIG. ) to (d) are the fourth
A schematic diagram showing the signal transfer status at each point in the figure,
Figure 6 shows time charts 1, 5 and 7 (
a) to (c) are schematic diagrams showing the signal transfer state at each point in time of FIG.
Shift ■-register, 3.23... Vertical CCD shift register, 4... Horizontal CCD shift register scanning circuit, 24... Transfer gate electrode, 25... Horizontal vertical transfer gate electrode, 26 . . . Transfer gate electrode scanning circuit, 27 . . . Horizontal/vertical transfer gate electrode scanning circuit. (Kyuden complete area) 1 (IFCCD shift and vertical CCD shift and Ji'suko CCD shift drain entered, served daily winter experience 1 Figure

Claims (1)

[Scope of Claims] (1) In a solid-state imaging device having a two-dimensionally arranged photoelectric conversion region and a transfer section that transfers signal charges photoelectrically converted by the region to the outside, the transfer section is It is composed of a horizontal CCD shift register group adjacent to the photoelectric conversion area and a vertical CCD shift register connected to one end of the shift register group, and a transfer electrode of each horizontal CCD shift register constituting the horizontal CCD shift register group. A solid-state imaging device characterized in that CCD shift registers are formed independently of each other for each horizontal CCD shift register. (2) One horizontal scanning line signal is composed of signal charges of one horizontal column of photoelectric conversion areas, and the signal charges of two horizontal columns of photoelectric conversion areas of every other column are scanned by 2:1 interlaced scanning (or
A driving method in which two consecutive horizontal scanning lines are configured in the scanning order (interlaced scanning), or one horizontal scanning line signal is composed of signal charges of one horizontal column of photoelectric conversion areas, and one horizontal scanning line signal is composed of signal charges of two consecutive photoelectric conversion areas. When driving the solid-state image sensor according to claim 1 using a driving method in which the horizontal row of signal charges constitutes two consecutive horizontal scanning lines in non-interlaced scanning, (a) from the photoelectric conversion region to the horizontal CCD; (b) driving the vertical CCD shift register and each horizontal CCD shift register at a speed synchronized with the scanning speed of the horizontal scanning line; (c) photoelectric conversion area; The interval between the horizontal transfer start times for starting the driving of the corresponding horizontal CCD shift registers between the two horizontal columns is defined as follows: (1) The scanning order of the horizontal scanning line group is in the same direction as the transfer direction of the vertical CCD shift register. In each case, in one horizontal scanning period, the position in the vertical CCD shift register corresponding to the horizontal scanning line to be scanned first among the two horizontal columns corresponds to the horizontal column to be scanned next among the two horizontal columns. The time is the time required for the vertical CCD shift register to transfer the signal to the position in the vertical CCD shift register where is the horizontal column of the horizontal scanning line to be scanned first among the two horizontal columns from the position in the vertical CCD shift register corresponding to the horizontal column of the horizontal scanning line to be scanned later among the two horizontal columns, respectively, from one horizontal scanning period. Vertical CC up to the position in the vertical CCD shift register corresponding to
A method for driving a solid-state image sensor, characterized in that the time is calculated by subtracting the time required for a D shift register to transfer a signal. (3) Four spatially continuous horizontal rows of photoelectric conversion regions are arranged in order: the first horizontal row of photoelectric conversion regions, the second horizontal row of photoelectric conversion regions, the third horizontal row of photoelectric conversion regions, and the fourth horizontal row of photoelectric conversion regions. In 2:1 interlaced scanning (or interlaced scanning) in which the horizontal rows of photoelectric conversion regions are horizontal rows of The sum constitutes one horizontal scanning line, and the parallel sum of signal charges of the horizontal column of the third photoelectric conversion area and the horizontal column of the fourth photoelectric conversion area is scanned next to the one horizontal scanning line. In driving the solid-state imaging device according to claim 1 using a driving method that configures one horizontal scanning line, (a) signal charges are transferred from the photoelectric conversion region to the horizontal CCD shift register group at the same time; (b) ) driving the vertical CCD shift register and each horizontal CCD shift register at a speed synchronized with the scanning speed of the horizontal scanning line; (c) a horizontal row of first photoelectric conversion regions and a horizontal row of third photoelectric conversion regions; , and the second horizontal row of photoelectric conversion regions and the fourth
1. The scanning order of the horizontal scanning line group is vertical CCD shift. If the transfer direction is the same as the register transfer direction, each of the two horizontal columns is moved from the position in the vertical CCD shift register corresponding to the horizontal column of the horizontal scanning line to be scanned first among the two horizontal columns in one horizontal scanning period. Vertical C corresponding to the next horizontal row to scan
The time is the time required for the vertical CCD shift register to transfer the signal to the position in the CD shift register, and 2. If the scanning order of the horizontal scanning line group is in the opposite direction to the transfer direction of the vertical CCD shift register, Each from one horizontal scanning period, from the position in the vertical CCD shift register corresponding to the horizontal scanning line to be scanned later among the two horizontal columns to the horizontal column to the horizontal scanning line to be scanned first among the two horizontal columns. (d) The horizontal row of the first photoelectric conversion area or the third photoelectric conversion area. The horizontal transfer start time of the horizontal column of the second photoelectric conversion area and the horizontal transfer start time of the horizontal column of the fourth photoelectric conversion area are 1. The scanning order of the horizontal scanning line group is the vertical CCD. In the case of the same direction as the transfer direction of the shift register, between the positions in each vertical CCD shift register corresponding to the horizontal row of the first photoelectric conversion area and the horizontal row of the second photoelectric conversion area or the third photoelectric conversion area The vertical CCD shift register is connected between the positions in each vertical CCD shift register corresponding to the horizontal row of the fourth photoelectric conversion area and the horizontal row of the fourth photoelectric conversion area.
2. If the scanning order of the horizontal scanning line group is opposite to the transfer direction of the vertical CCD shift register, it is delayed by the time required for the shift register to transfer the signal. A method for driving a solid-state image sensor.