Television – Camera – system and detail – Solid-state image sensor
Reexamination Certificate
1998-01-30
2002-03-12
Ho, Tuan (Department: 2612)
Television
Camera, system and detail
Solid-state image sensor
Reexamination Certificate
active
06356305
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image-pickup apparatus and a method for driving the same, adapted for reading signal charges accumulated in a plurality of photodetection portions provided on a predetermined plane, through vertical transfer lines and a horizontal transfer line, which extend perpendicular to each other on the plane.
2. Related Background Art
The conventional electronic cameras and video cameras are equipped with an image-pickup apparatus, for example, composed of CCD image sensing devices or MOS image sensing devices. Some conventional examples of the image-pickup apparatus of this type will be described.
FIG. 1
is a drawing to show the structure of a conventional image-pickup apparatus of a progressive scan type (the first conventional example).
In
FIG. 1
, the image-pickup apparatus of the first conventional example has photodetection portions
51
of photodiodes or the like arrayed two-dimensionally on an image-pickup surface. Vertical transfer lines
52
(vertical CCD groups) are placed each through a transfer gate
53
between vertical strings of these photodetection portions
51
(vertical lines).
For each of the vertical transfer lines
52
, 3-phase electrodes &phgr;
1
-&phgr;
3
for transfer of charge are provided at regular intervals, and a horizontal transfer line
54
(a horizontal CCD group) is arranged along the horizontal direction on the output end side of the vertical transfer lines
52
. An output amplifier
55
is connected to the output side of this horizontal transfer line
54
.
In the image-pickup apparatus of this structure signal charges according to quantities of light received by the image-pickup surface are accumulated in the respective photodetection portions
51
.
When a high voltage is applied to the electrodes &phgr;
2
, &phgr;
3
, potential wells for accumulating the signal charge are established under the electrodes &phgr;
2
, &phgr;
3
. At this time a vertical length L
10
of a potential well is approximately two thirds of a vertical width L
20
of a horizontal line, as shown in
FIG. 1. A
horizontal line means one row or two or more rows of photodetection portions
51
arranged along the horizontal direction and a vertical width of a horizontal line means a width along the vertical direction, of the photodetection portions
51
forming the horizontal line.
The signal charges accumulated in the photodetection portions
51
in this state are transferred at one time to the respective potential wells established in the vertical transfer lines
52
, through the transfer gate
53
.
When 3-phase driving pulses are then applied to the electrodes &phgr;
1
-&phgr;
3
, the signal charges in the potential wells are successively transferred in the vertical direction.
The signal charges of one horizontal line outputted from the group of vertical transfer lines
52
are taken into the horizontal transfer line
54
during a horizontal blanking interval. The signal charges of one horizontal line thus taken in are transferred in the horizontal direction to the outside over one horizontal scan period. The horizontal scan period means a period necessary only for the signal charges transferred from the respective vertical transfer lines into the horizontal transfer line to be successively transferred and be outputted to the outside, and the horizontal blanking interval means a period in which the transfer operation of signal charge is interrupted in the horizontal transfer line.
The outputs from the horizontal transfer line are subjected to the well-known color signal process and &ggr; correction or the like, thus generating image signals of a frame unit.
Next,
FIG. 2
is a drawing to show the structure of a conventional image-pickup apparatus of a two-line-mixed interlace scan type (the second conventional example).
In
FIG. 2
, the image-pickup apparatus of the second conventional example has photodetection portions
61
of photodiodes or the like arrayed two-dimensionally on the image-pickup surface. Vertical transfer lines
62
(vertical CCD groups) are placed each through transfer gate
63
between the vertical strings of these photodetection portions
61
.
For each of the vertical transfer lines
62
, 4-phase electrodes &phgr;
1
-&phgr;
4
for transfer of charge are provided at regular intervals and a horizontal transfer line
64
(a horizontal CCD group) is placed along the horizontal direction on the output end side of the vertical transfer lines
62
. An output amplifier
66
is connected to the output side of this horizontal transfer line
64
.
The image-pickup apparatus of this structure can perform interlace reading.
Described below is a case where an odd field is read.
First, a high voltage is applied to the electrodes &phgr;
1
-
3
, whereby potential wells for accumulating the signal charge are established under the electrodes &phgr;
1
-
3
. At this time the vertical length L
11
of each potential well is approximately three quarters of the vertical width L
21
of a horizontal line (composed of the photodetection portions in two rows), as shown in FIG.
2
.
The signal charges accumulated in the photodetection portions
61
in this state are transferred at once to a potential well established in each of the adjacent vertical transfer lines
62
, through the transfer gate
63
. At this time signal charges accumulated in the photodetection portions
61
in the n-th row (n is an odd number) and in the (n+1)th row are mixed in one potential well, thus generating a signal charge of one horizontal line.
Then 4-phase driving pulses are applied to the electrodes &phgr;
1
-&phgr;
4
, whereby the signal charges in the potential wells are successively transferred in the vertical direction.
The horizontal transfer line
64
takes in the signal charges of one horizontal line outputted from the group of vertical transfer lines
62
during a horizontal blanking interval. The signal charges of one horizontal line thus taken in are transferred in the horizontal direction over one horizontal scan period.
The outputs from the horizontal transfer line are subjected to the well-known color signal process and &ggr; correction or the like, thus generating image signals of an odd field.
For reading an even field, the signal charges accumulated in the photodetection portions
61
in the n-th row (n is an odd number) and in the (n−1)th row are mixed in the potential wells established under the electrodes &phgr;
4
, &phgr;
1
, &phgr;
2
, thus generating signal charges of one horizontal line.
Next,
FIG. 3
is a drawing for explaining the operation of a conventional image-pickup apparatus of the CSD method (the third conventional example).
In
FIG. 3
, the image-pickup apparatus of the third conventional example has electrodes &phgr;
1
-&phgr;m arranged at regular intervals on each vertical transfer line
71
. On the output end side of the vertical transfer line
71
a horizontal transfer line
74
is placed through storage area
72
and gate portion
73
. This storage area
72
is a region for temporarily storing a signal charge and an electrode &phgr;C for establishing a potential well for storage of charge is placed on the storage area
72
. The gate portion
73
is a transfer gate for electrically opening or closing the region between the storage area
72
and the horizontal transfer line
74
, and a gate electrode &phgr;T is placed on the gate portion
73
.
On the other hand, placed on the horizontal transfer line
74
is an electrode &phgr;H for establishing potential wells for transferring signal charges of one horizontal line taken in from the vertical transfer lines
71
, in the horizontal direction.
In the image-pickup apparatus of this structure, a high voltage is applied at once to the electrodes &phgr;
1
-&phgr;m on each vertical transfer line
71
, thus establishing a potential well over the entire length of the vertical transfer line
71
. In this state, a signal charge in each photodetection portion (not illustrated) forming one horizontal line is transferred to the potential
Ho Tuan
Nikon Corporation
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