JPH01117483A - Image pickup device - Google Patents

Abstract

PURPOSE:To easily obtain a still picture with high resolution by a conventional video signal processing circuit by reading out an odd number line of electric signal and an even number line of electric signal while an image pickup means is shut by a shutter in a different field period sequentially. CONSTITUTION:After all lines of electric signals of an image pickup means having plural photodetector parts arranged in row and column shape are cleared once, an object image is made incident on to the image pickup means for a prescribed time only by the shutter. While the image pickup means is shut by the shutter, odd line and even line of electric signals are read sequentially in a different field period sequentially while the image pickup means is shut by the shutter. Thus, a still picture signal comprising two interlaced fields is formed in this way. Thus, interlace video signals of two fields picked up simultaneously are obtained and the still picture with high resolution is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an imaging device that can obtain a frame signal with high resolution and no blur.

[Prior art]

In conventional area sensors, the number of cells in the vertical direction of the imaging section is
In the case of the NTSC system, the number of scanning lines is 2, which is about half of the 525.
It consists of 45 cells, and since each cell has a photosensitive and transfer function, the number of picture elements that can be stored at a time is 245 rows, that is, one field. After reading out the signal charge for each cell,
An interlace operation is performed in which the effective photosensitive area of the image is moved and imaged, and this one field is then read out.
Images for J frames were obtained.

This type of system is extremely compatible with the NTSC television system, and although the number of cells is small,
Image quality with excellent resolution was obtained.

[Problem that the invention seeks to solve]

However, recently, research and development has begun to be carried out on the use of COD to take images and magnetically record them instead of the conventional silver halide film, which is called a still φ video P camera or video photography. In such a system, when recording one frame in order to obtain high image quality, it consists of two fields that are slightly shifted in time, or 1/60 seconds apart in terms of TV signal rate. However, if a moving subject is captured, an unsightly image will be obtained, and if only one field is recorded to avoid this phenomenon, the vertical resolution will be reduced by about half. Was.

SUMMARY OF THE INVENTION An object of the present invention is to improve such conventional drawbacks and provide an imaging device capable of capturing a frame suitable for a still video camera.

[Means for solving problems]

In order to achieve such an objective, the imaging device of the present invention has the following features:
An imaging means having a plurality of light receiving parts arranged in rows and columns, and after once clearing the electrical signals of all the rows of the imaging means, an object image is incident on the imaging means for a predetermined time using a shutter, and then an aperture shutter is used. readout means for forming a still image signal consisting of two interlaced fields by sequentially reading out electrical signals in odd-numbered rows and electrical signals in even-numbered rows of the imaging means in different field periods with the imaging means shielded from light; , equipped with.

[Effect]

As a result, it is possible to obtain interlaced video signals of two fields captured simultaneously, and it is possible to obtain a high-resolution still image.

〔Example〕

The present invention will be explained below along with examples using the drawings.

FIG. 1 shows a frame transfer type C suitable for the imaging device of the present invention.
It is a figure showing the composition of OD.

Reference numeral 1 in FIG. 1 is an imaging unit of the frame transfer type COD.

For example, in the case of the NTSC system, the number of cells in the vertical direction of this imaging section is set to approximately 490, which is approximately equal to the number of scanning lines. That is, it has about twice the number of cells as a conventional frame transfer type CCD. The number of cells in the horizontal direction is, for example, about 390 or 570, which corresponds to the color subcarrier frequency.

1 in FIG. 1 shows only 9 rows and 4 columns, respectively. Reference numeral 2 in FIG. 1 schematically shows an electrode for applying a voltage to the imaging section for receiving and transmitting light.

3 is a storage section, and as shown in the figure, the number of lines in the vertical direction is approximately half the number of lines of the imaging section. Therefore, this storage section is almost the same as the storage section of a conventional frame transfer type CCD. It consists of an equal number of cells.

Reference numeral 4 schematically indicates an electrode to which a voltage is applied for transferring charges, similar to the imaging section.

Reference numeral 5 denotes a horizontal transfer register, which is composed of a row of charge transfer sections having approximately the same number of cells in the horizontal direction as the imaging section and storage section.

Reference numeral 6 schematically shows an electrode to which a voltage is applied to transfer the charges of the horizontal transfer register 5. As shown in FIG.

7 is an amplifier that converts the charge transferred from the horizontal transfer register 5 into a voltage output.

It should be noted that the image sensor of the embodiment has a
It has a second horizontal transfer register 8 that is almost the same as the horizontal transfer register 5. Reference numeral 9 schematically shows an electrode to which a voltage is applied to transfer the charges in the second horizontal transfer register. Further, 10 indicates an amplifier for converting the transferred charges into voltage.

Conventionally, charge transfer methods include single-phase drive, two-phase drive,
There are several methods such as a three-phase drive method and a four-phase drive method, and any of them can be applied to the CeD configuration of this embodiment, but in order to simplify the explanation below, a single-phase drive method will be used as an example. This will be explained using FIG.

The single-phase drive method referred to here is based on Japanese Patent Application Laid-open No. 55-
11394 "Charge Transfer Device" may be used, and the detailed operation will be omitted.

In FIG. 2, numeral 20 indicates a channel stop for preventing charge leakage between cells in the horizontal direction.

Reference numeral 21 indicates a polysilicon electrode of the imaging section, and the area under this electrode is a polysilicon electrode with different potential states in the silicon.
It consists of a region and an nth region.

Reference numeral 22 denotes a region in which a virtual electrode is formed in silicon, and is made up of an n-th region and a (2)-th region having different potential states in silicon.

In the vertical direction, one pixel cell is constructed from the first to (ii)th regions.

23 indicates a second horizontal transfer register area. In this region, the polysilicon electrode is formed in a diagonal shape (tooth-shaped), and the area under this polysilicon electrode is divided into regions I' and II' with different potential states as shown in the figure. The I' and I' regions have the same potential, but are separated by a channel stop.The m' and IV' regions are set to the same potential as the virtual electrode section 22 of the imaging section.

24 and 25 are configured similarly to 21 and 22 of the imaging section.

FIG. 3 is a diagram showing the internal potential state of the COD having the configuration shown in FIG.

Reference numeral 30 in FIG. 3 is a polysilicon electrode of the imaging section corresponding to FIG. There is. The area below this polysilicon electrode 30 is as explained in FIG. , ■ regions, and the ■ region has a higher potential state for electrons than the n region. The dotted line in the figure shows the potential of the polysilicon electrode 30 in a high negative potential state, and the solid line shows the potential of the polysilicon electrode 30 in a slightly negative or positive state, respectively.

The potential of the virtual electrode portion 22 in FIG. 2 is as shown in FIG. 3 (the potential in the n region is slightly higher than the Therefore, if a constant voltage is applied to the polysilicon electrode 30, charges will be accumulated, and if a pulsed voltage is applied, the charges will be transferred.

In FIG. 3, numeral 31 indicates a polysilicon electrode of the second horizontal transfer register. This electrode is connected to other electrodes 30.32.
33, and an independent voltage is applied. The internal potentials of the horizontal transfer register portions are as shown below the polysilicon electrode 31 in FIG. 3, respectively.

In FIG. 3, numeral 32 indicates a polysilicon electrode of the storage section. The internal potential of this storage section is similar to that of the imaging section. 33 indicates a first horizontal transfer register (5 in the first diagram). The configuration is similar to the second horizontal transfer register, but
It is slightly different in that it is closed on one side with a channel stop.

FIG. 34 shows the potential state of the channel stop section. The function of charges in a portion of the second horizontal transfer register will be explained below. By applying a pulse voltage to the polysilicon electrode 30, the electric charge accumulated in the n region of the imaging section increases as shown by the dotted line in FIG. It enters the potential well region.At this time, if a slightly negative or positive potential is applied to the polysilicon electrode 31 of the second horizontal transfer register, the potential /l/It of the I', n' region will change. Potential state 1 shown by the solid line: F), the charge in the ■ region is
'Enter territory.

Next, when a high negative potential is applied to this electrode 31, I
Each potential in the ', n' region is in the state shown by the dotted line, and the charge in the ■' region is transferred through the ■' region (which has a constant potential shown by the dotted line) to the ■' region (which has a constant potential shown by the dotted line). Ru. At this time, when a slightly negative or positive current is applied to the polysilicon electrode 32 of the storage portion, this region ll/1. ■The potential of the # region decreases as shown by the solid line, and the charge that was in the ■'' region is transferred to the ■'''' region and is transferred to the ■' region.

In this way, the charges transferred to the region ■' of the storage section are
By applying a pulsed voltage to the polysilicon electrode 32 of the storage section, 1l11. ■The potential of the #region becomes as shown by the dotted line, and is transferred to the ■'region via the ■'region. Therefore, by applying a pulse voltage as a drive signal to the electrode 32, the accumulated charge is sequentially transferred from ■'→■'→■' to the first horizontal transfer register 5, and then a pulse signal is applied to the electrode 33. This makes it possible to send the data to the outside through the first horizontal transfer register. The charge flow described above indicates that it is possible to operate with almost the same driving as a conventional frame transfer type COD without a second horizontal transfer register.

Next, a description will be given of the flow of charges when a signal is read out to the outside through the second horizontal transfer register.

■The charge transferred in the area is transferred to the storage area by applying a slightly negative or positive potential to the polysilicon electrode 32 of the storage area in the above operation. A high voltage is applied (IIl, ■# potential is maintained as shown by the dotted line), and a pulse-like voltage is applied to the second horizontal transfer register 31 to transfer I', n'
By shifting the potential of the region alternately to the state shown by the solid line and the dotted line, the charge in the ■′ region becomes I′→■′→■′
The signal is transferred horizontally to the →■' area, and the signal is read out to the outside through an amplifier.

Next, the operation when operating as an actual camera will be explained using FIG. 4.

FIG. 4(a) shows an operating state diagram when operating as a still φ video camera, and FIG. 4(b) shows a state diagram when operating as a conventional video camera.

First, a case where the camera is operated as a still video camera will be explained.

In the state a-1 in Fig. 4(a), a control circuit (not shown) clears the charge accumulated due to dark current through the anti-blooming drain immediately before the exposure operation, or operates the COD at high speed. This shows an all-clear state in which the charge is discharged to the outside and cleared.

Next, the shutter opens, and the state shifts to the exposure state or the storage state a-2 of the imaging section and the reading state a-3 of the first field of the horizontal register 615.

In this state, the shutter is closed after a predetermined exposure time, and after accumulating image signals (charges) on each cell shown in the first diagram,
First, the accumulated charges in the cells of the imaging section are transferred two rows at a time. That is, in the case of the embodiment in FIG. 1, the charges accumulated in cells (1, 1) to (1, 4) are transferred to cells (4, 1) to [4, 4] of the storage section through the second horizontal register. , (2,1)~(2
, 4) is transferred to the horizontal register 8. Similarly, charges accumulated in the cell portions of other rows are also transferred for two rows. This allows (3,1) to (3,4
), (4,1)~(4,4).

(5,1) - (5,4), (6,1) - (6,4)
, (7,1)~(7,4), (8,1)~(8,
4), (9,1) to (9,4) parts are (1,1) to (1,4), (2,1) to (2,4), respectively.
), (3,1)~(3,4), (4,1)~(
4,4).

(5,1)~(5,4), (6,1)~(6,4)
, (7,1) to (7,4).

After charges are transferred for two rows in this manner, the charges transferred to the second horizontal register are sent out to the outside via the amplifier IO. As a result, the cell parts (2, 1) to (2, 4) transferred to the second horizontal register 8 as described above are
The accumulated charge is output serially.

After this, two rows of charges accumulated in the cells of the imaging section are transferred again.

As a result, the charges transferred to the (1,1) to (1,4) sections, that is, the charges accumulated at (a, i) to (3,4) during exposure, are transferred to the cells of the storage section via the horizontal register. 4,1〕～(
4, 4), and the charges transferred to the (2, 1) to (2, 4) portions, that is, the charges accumulated in (4, 1) to (4, 4) during exposure, are transferred to the horizontal register 8. will be forwarded to.

Also, at this time, the charge transferred to the cell section of each row of the storage section is 1
Lines are transferred. Therefore, the charges transferred to the (4,1) to (4,4) portions last time, that is, the charges transferred to the (4,1) to (4,4) portions during exposure.
The charges accumulated in are transferred to parts (3,1) to [3,4]. After this, the readout operation of the charges transferred to the horizontal register 8 is performed again, and the charges accumulated during exposure (4, 1) to (4, 4) transferred to the horizontal register as described above are sent out serially. be done.

Thereafter, in the same way, the charges accumulated in the cells of the imaging section are transferred for two rows, the charges transferred to the cells of the storage section are transferred for one row, and the charges transferred to the horizontal register 8 are read out alternately. By executing, (2,1) to (2,4), (4,1) to (4,
4), (6,1)~(6,4), (8,1)~
The charges accumulated in (8, 4) are sequentially sent out. That is, the read operation of the first field is executed. Text exposure (1,1) to (1,4), (3,1) to (3,
4).

(5,1)~(5,4), (7,1)~(7,4)
The charges accumulated in the storage parts (1, 1) to (1
,4), [2,1]~(2,4), (3,1)~
(3,4), transferred to (4,1) to (4,4). After the first field read operation is executed in this manner, a transition is made to the second field read state (a-4 state). In the a-4 state, the charges transferred to the cells in each row of the storage section are transferred for one row, and then the charges transferred to the first horizontal register 5 are read out from the horizontal register during exposure ( 1,4)～(4,4), (3,
1)~(3,4), (5,1)~(5,4), (
The charges accumulated in 7,1) to (7,4) and (9,1) to (9,4) are sent out, and the reading of the second field is completed.

As described above, according to the present invention, the image signal for one frame captured at the same time can be read out as in normal TV operation (first field, then interlaced second field).

Next, the operation of this device as a normal video camera will be explained.

The state b-1 in FIG. 4(b) corresponds to the clearing operation a-1 in FIG. 4(a). However, this operation is not essential.

In this case, there is no need for a shutter, and the storage and readout operations return <1 at the same time. b-2, b-2', . . . indicate the accumulation states, and the dash symbol indicates the second field. In other words, the charges accumulated in b-2 (first field) are read out in b-3, and the charges accumulated in b-2' (second field) are read out in b-3'. It is.

State b-4 indicates a state in which the charges accumulated in the imaging section are transferred to the accumulation section.

In the frame transfer type COD according to this embodiment, the number of vertical cells in the imaging section is 490, and the number of cells in the storage section is 24.
5, the operation and interlacing method when transferring from the imaging section to the storage section are different from normal frame transfer type COD. This operation will be explained using FIG. 1.

First, after exposure accumulation is performed in the b-2 state, the accumulated charge of the imaging section is transferred to the storage section in the b-4 state. In the transfer operation, first, (1, 1).

The charges accumulated in (1, 2), (1, 3), (1, 4) pass through the second horizontal register 8 to the accumulation section 3.
(4,1).

Transferred to (4,2), (4,3), (4,4). Then (2,1), (2,2), (2
, 3) and (2, 4) in the same way, (4, 1)
), (4,2), (4,3), (4,4)
.

will be forwarded to. At this time, no pulse voltage is applied to the storage section, and the charges accumulated at (1, 1) to (1, 4) during exposure are held at (4, 13 to (4, 4)) (.

As a result, (4,1) to (4,43) have the imaging unit (1,1).
) to (1,4) and (2,1) to (2,4) are added together.

Next, the charges added at (4, 1) to (4, 4) of the storage section are transferred to (3, 11 to (3, 4)), and again as described above (2 rows of the imaging section) , i.e. (3,1) to (3,4)
.

(4,1)~(4,4) charges for two lines are (4,1)~
Transfer and add to (4, 4). After that, in the same way, one line transfer operation of the storage unit and two lines of (4, 1) to (
By repeating the transfer addition operation to 4 and 43, (1, 1) to (1, 4) of the storage section are
) and the sum signal of (2,1) to (2,4) is (2,1)
~(2,4) has (3,1)~(3,4) and (4,1
) to (4,4) is added to [3,1] to (3,43
(5,1) to (5,4) and (6,1) to (6,4
) is added to [4,1] to (4,4), and (7
, 1) to (7, 4) and (8, 1) to (8, 4) are transferred, respectively.

After this, the state shifts to b-2' and b-3, and the exposure accumulation operation is executed, and as described above (the signal transferred to the accumulation section 3 is sequentially transferred to the horizontal register 5 row by row, and the horizontal The signal transferred to register 5 is transferred to horizontal register 5.
Sent from As a result, the first field read operation is executed.

After the readout operation for the first field is completed in this way, the operation of transferring the charges accumulated in the imaging section 1 at b-2' to the storage section 3 is executed at b-4.

In this case, since it is a read operation for the second field, the cells to be transferred from the imaging unit to the (4,1) to (4,4) sections are shifted by one row, and the transfer and addition for two columns of the imaging unit is performed. is executed.

In other words, the second field is (2,1) to (2,4)
and the accumulated charge of (3,1) to (3,4) parts, (4,1)
〜(4,4) and (5,1)〜(5,4) accumulated charge, (6,1)〜(6,4) and (7,1)〜(7,4)
The charges accumulated in the storage section 3 are transferred and added to (4, 1) to (4, 43), respectively, and the added charges are transferred and accumulated in each row of the storage section 3. After this, b-3' adds the charges accumulated in the storage section 3. The readout operation for the second field is completed by sending out the charges by the horizontal register 5. In this way, when adding two rows of imaging unit cells, the first field transfer addition operation and the second field transfer addition operation are performed. By shifting the transfer and addition by one line, a signal interlaced with the first field can be obtained, and images can be captured as a normal video camera.

〔effect〕

As explained above, according to the imaging device of the present invention, it is possible to obtain interlaced two-field signals in one imaging operation, and the image signal for one frame can be processed in the same signal form as in normal TV signal processing. A high-resolution still image can be easily obtained using an ordinary video signal processing circuit.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the configuration of COD according to the present invention, and FIG.
The figure is a configuration diagram showing the main part configuration of the COD shown in Figure 1, Figure 3 is an operation explanatory diagram for explaining the operation of Figure 2, and Figure 4 (
FIGS. 2A and 2B are schematic sequence diagrams for explaining the operation of the COD shown in the first figure according to the present invention.

Claims (1)

[Scope of Claims] Imaging means having a plurality of light-receiving parts arranged in rows and columns; and after once clearing the electrical signals of all the rows of the imaging means, an object image is displayed on the imaging means only for a predetermined period of time by a shutter. A still image signal consisting of two interlaced fields is obtained by dividing the electrical signals of the odd-numbered rows and the electrical signals of the even-numbered rows of the imaging means into different field periods and sequentially reading them while the imaging means is shielded from light by the shutter. An imaging device comprising: a readout means for forming an image;