JPS63152279A - Solid-state image pickup element - Google Patents

Abstract

PURPOSE:To improve vertical resolution and to avoid increase in an after-image by transferring a signal charge from a photosensitive section to a transfer section so as to send simultaneously fields of odd and even number of lines while having two vertical transfer sections. CONSTITUTION:The signal charge stored in the photosensitive section 11 in response to the incident light is transferred at a period of 1/30 to an odd number line vertical transfer section 12a for the odd number line and to an even number line vertical transfer section 12b for an even number line. Moreover, the signal charge of the line selected by the vertical transfer change over section 15 is transferred to the field memory section 16 and the signal charge fed to the field memory section 16 is transferred in the field memory section 16 in parallel at each horizontal scanning period and fed to the horizontal transfer section 13. Moreover, it is read serially in one horizontal scanning period, and outputted to an output terminal 14 as the video signal by one field of the next series. Thus, the vertical resolution and the after-image are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to the structure of a solid-state image sensor in which pixels capable of accumulating signal charges are arranged two-dimensionally.

``Prior art'' Conventionally, the number of columns of the vertical transfer section of a solid-state image sensor used in a television camera is one, and the number of stages is approximately half the number of photosensitive sections in the vertical direction. The screen is made up of a number of scanning lines running sequentially in the horizontal direction, as shown in Figure 3A.
In order to reduce flicker, interlace scanning is performed as shown in FIG. 3B.

Lines (1) to (1) scanned in the first 1/60 second field
242), the field is scanned as lines 243 to 480, and these two fields form one composite screen (one frame).

FIG. 4 shows an example of a model of a conventional solid-state image sensor. This solid-state image sensor is composed of a photosensitive section 11, a vertical transfer section 12, and a horizontal transfer section 13.

The signal charges generated in the photosensitive section 11 in response to the incident light C2 are:

The data is transferred to the vertical transfer section 12 during the vertical blanking period.

The signal charges transferred to the vertical transfer section 12 are transferred within the vertical transfer section 12 in parallel every horizontal scanning period.

It is sent to the horizontal transfer section 13. The signal charges sent to the horizontal transfer section 13 are read out in series during one horizontal scanning period, and are outputted to the output terminal 14 as a time-series one-field visual disturbance signal.

As storage methods for forming a video signal for one field, there are a frame storage method and a field storage method, which will be described below.

FIG. 5 shows the frame storage method. In this method, in the first field, the signal charges of pixels 1, 3, 5, . Vertical transfer section 1 for signal charges
Transfer with 2. That is, interlacing every other pixel in the vertical direction is completely performed. Therefore, only when the subject is stationary, the vertical resolution is determined by the number of vertical photosensitive sections, and in the case of a standard television, it is 485 TV lines. However, if the object is moving, this feature cannot be utilized because there is a time lag in transfer between the first field and the next field.

Furthermore, since the signal accumulation time per pixel is 1/30 seconds, there is a drawback that there is more afterimage compared to the field accumulation method described next.

FIG. 6 shows the field storage method. In this method, the signal charges of two vertically adjacent pixels in the photosensitive area 11 are added together and output. In the figure, the signal charges of pixels 1 and 21, pixels 3 and 4, and pixels 5 and 6 are in the first field, and in the next field, the signal charges are in pixels 2 and 31, pixels 4 and 51, pixels 6 and 7.
The signal charges of are added together. The signal accumulation time per pixel is 1/60 seconds, which is half that of the frame accumulation method, and the residual image is reduced accordingly. On the other hand, the vertical resolution is approximately 350 TV lines because each scanning line cannot be considered completely independent.

"The problem that the invention attempts to solve" As mentioned above, the conventional frame storage method.

The vertical resolution is 480 TV lines in a still image because it is completely interlaced every other pixel in the vertical direction.
The resolution of videos deteriorates. Also, the signal accumulation time is 17
Since the time is 30 seconds, there is a drawback that afterimages increase. In the traditional field storage method.

Since the signals of two adjacent pixels in the vertical direction are combined and output, the vertical resolution is approximately 350 TV lines, which is lower than that of the frame accumulation method.

"Means for Solving the Problems" The solid-state image sensor of the present invention includes a photosensitive section in which pixels capable of accumulating signal charges are arranged two-dimensionally, and pixels arranged in each vertical column of the photosensitive section. The odd field vertical transfer section transfers the signal charges accumulated in the odd-numbered pixels, and the odd-field vertical transfer section transfers the signal charges accumulated in the even-numbered pixels to the The even field vertical field transfer section, which is transferred simultaneously with the transfer, the odd field vertical transfer section provided for each vertical column of each pixel, and the even field vertical transfer are switched for each field to output the signal charge. Vertical transfer - switching section, a field memory section to which the signal charges output from these vertical transfer switching sections are transferred, and the signal charges transferred to the field memory section are transferred in parallel and output in series. It consists of a horizontal transfer section.

As described above, the basic feature of the present invention is that by having two vertical transfer sections, signal charges can be transferred from the photosensitive section to the transfer section by simultaneously transferring fields of odd lines and fields of even lines. , it is possible to improve the time lag, which is a drawback of the above-mentioned frame transfer method, and further improve the vertical resolution and afterimage by reducing the signal accumulation time to 1/60 seconds.

"Example" Next, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a model of a solid-state image sensor according to the present invention. This solid-state sensor element includes a photosensitive section 11, an odd field vertical transfer section 12a, an even field vertical transfer section 12b, and a vertical transfer switching section 15 that switches between the odd field vertical transfer section 12a and the even field vertical transfer section 12b. and.

It is comprised of a field memory section 16 that stores the signal from the vertical transfer switching section 15, and a horizontal transfer section 13 that transfers the signal from the field memory section 16 to an output terminal.

The signal charges accumulated in the photosensitive section 11 according to the incident light are transferred to the odd line vertical transfer section 12H at the same time during the vertical blanking period at 1/30 cycle as shown in the timing chart of FIG.

Even-numbered lines are transferred to the even-line vertical transfer section 12b. The signal charges transferred to the respective vertical transfer units 12a and 12b are further transferred to the field memory unit 16 at high speed during the vertical blanking period, and the signal charges of the line selected by the vertical transfer switching unit 15 are further transferred to the field memory unit 16. The signal charge sent to the field memory section 16 is transmitted every horizontal scanning period (=
The signals are transferred in parallel within the field memory section 16 and sent to the horizontal transfer section 13. The signal charges sent to the horizontal transfer unit 13 are serially read out in one horizontal scanning period and transferred to the next series of signal charges.
The video signal for one field is output to the output terminal 14.

Next, the remaining fields are selected by the vertical transfer switching section 15, and the same operations as described above are performed thereafter to obtain video signals for the remaining fields.

The charge accumulation time in the photosensitive section 11 is determined by the vertical transfer section 12a.

This is one field period immediately before transfer to 12b.

"Effects of the Invention" As explained above, according to the present invention, the pixels of the photosensitive section arranged two-dimensionally are assigned to the odd and even lines of the television screen, and the signal charges generated on the photosensitive section are simultaneously read out and accumulated. By sequentially transferring them (-), it is possible to improve the vertical resolution, and even if the vertical transfer section is moved from the photosensitive section 11 to C21 degrees for 1/30 seconds, the charge accumulation period is still long?
:1 field has the effect of not increasing afterimages.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the solid-state image sensor of the present invention, FIG. 2 is a timing chart for transferring signal charges of the solid-state image sensor shown in FIG. 1, and FIG.
FIG. 4 is a block diagram showing a conventional solid-state image pickup device, FIG. 5 is a diagram showing a frame transfer method, and FIG. 6 is a diagram showing a field transfer method. Patent Applicant NEC Co., Ltd. Agent Kusano Single Phase 30 [Scanning] [221 Ifkulace] Ushi 40 Tsubo 50 Field of the Most Negative Sword 〉Field of Missing□ Field of the Most Talented Power 3 Next Field

Claims (1)

[Claims] (1) A photosensitive area in which pixels capable of accumulating signal charges are arranged two-dimensionally, and pixels are provided in each vertical column of the photosensitive area, and the signal charges accumulated in odd-numbered pixels are transferred. an even field vertical transfer section provided for each vertical column of pixels of the photosensitive section, to which signal charges accumulated in even-numbered pixels are transferred at the same time as the above-mentioned transfer; A vertical transfer switching section that switches between an odd field vertical transfer section and an even field vertical transfer section provided for each vertical column of pixels and outputs the signal charge for each field, and signals output from these vertical transfer switching sections. A solid-state imaging device comprising a field memory section to which charges are transferred, and a horizontal transfer section to which signal charges transferred to the field memory section are transferred in parallel and output in series.