Television – Camera – system and detail – Solid-state image sensor
Reexamination Certificate
1997-12-18
2003-01-28
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Solid-state image sensor
Reexamination Certificate
active
06512545
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to solid-state image pickup apparatus including a pixel section consisting of a large number of pixels, in which pixel signals corresponding to a full angle of view (field) can be read out at high frame rates.
Conventional XY addressing type solid-state image pickup apparatus are generally constructed as shown in FIG.
1
. The solid-state image pickup apparatus shown in
FIG. 1
includes: a horizontal scanning circuit
100
; a signal readout section
102
having “m” units of NMOS transistors
101
connected in X-direction; a vertical scanning unit
103
; and a pixel section
105
having pixels
104
arrayed in a matrix of “m” units in X-direction and “n” units in y-direction.
Vertical select lines G(
1
), G(
2
), G(
3
), G(
4
), G(
5
), G(
6
), . . . G(n−1), G(n) connected to the respective pixel rows each consisting of pixels
104
arrayed in X-direction are connected to a vertical scanning circuit
103
having a function for selectively supplying electric potentials to read out the signal. Horizontal select lines S(
1
), S(
2
), S(
3
), S(
4
), S(
5
), S(
6
), S(m−1), S(m) connected to the respective pixel columns each consisting of pixels
104
arrayed in Y-direction are connected to the signal readout section
102
for selectively reading the signal out of pixels
104
. While the respective gates of the NMOS transistors
101
of the signal readout section
102
are controlled by output pulses &PHgr;H(
1
), &PHgr;H(
2
), &PHgr;H(
3
), &PHgr;H(
4
) , &PHgr;H(
5
), &PHgr;H(
6
), . . . &PHgr;H(m−1), &PHgr;H(m) of a horizontal scanning circuit
100
, the sources thereof are respectively connected to the horizontal select lines S(
1
), S(
2
), S(
3
), S(
4
), S(
5
), S(
6
), . . . S(m−1), S(m) and the drains thereof are commonly connected to an output terminal SIG.
Referring to a timing chart of
FIG. 2
, the operation will now be explained of the solid-state image pickup apparatus as shown in FIG.
1
.
FIG. 2
is the timing chart for illustrating operation of the horizontal scanning circuit
100
and readout operation of the signal of pixels
104
when the vertical select line G(
1
) is selected. Upon inputting of start pulse HST and clock-pulse HCK to the horizontal scanning circuit
100
, output pulses &PHgr;H(
1
), &PHgr;H(
2
), &PHgr;H(
3
) , &PHgr;H(
4
), &PHgr;H(
5
), &PHgr;H(
6
), . . . &PHgr;H(m−1), &PHgr;H(m) which are driven to H-level for a duration of one period [time T(sec)] of the clock pulse HCK are sequentially outputted from the horizontal scanning circuit
100
in synchronization with the rising edge of the clock pulse HCK.
Since the NMOS transistors
101
included in the signal readout section
102
are turned on only for a time period during which H-level is being inputted to their respective gate, the NMOS transistor
101
corresponding to the respective output pulse is turned on only for the time period during which output pulse &PHgr;H(
1
), &PHgr;H(
2
), &PHgr;H(
3
), &PHgr;H(
4
), &PHgr;H(
5
), &PHgr;H(
6
), . . . &PHgr;H(m−1), &PHgr;H(m) of the horizontal scanning circuit
100
is driven to H-level. Accordingly, only for the time periods during which output pulses &PHgr;H(
1
), &PHgr;H(
2
), &PHgr;H(
3
), &PHgr;H(
4
), &PHgr;H(
5
), &PHgr;H(
6
), . . . &PHgr;H(m−1), &PHgr;H(m) of the horizontal scanning circuit
100
are driven to H-level, the corresponding horizontal select lines S(
1
), S(
2
), S(
3
), S(
4
), S(
5
), S(
6
), . . . S(m−1), S(m) are selected to read the signal out of pixels
104
. It should be noted that SIG in
FIG. 2
represents the pixel signal read out to the output terminal SIG as shown in
FIG. 1
, and (
1
,
1
), (
2
,
1
), (
3
,
1
), (
4
,
1
), (
5
,
1
), (
6
,
1
), . . . (m−1,1), (m,
1
) correspond to the array of pixels of the pixel section
105
in FIG.
1
.
In the conventional solid-state image pickup apparatus as shown in
FIG. 1
, if the number of pixels
104
included in the pixel section
105
is increased, the signal readout time corresponding to one frame, i.e., frame rate is prolonged nearly in proportion to the number of the arrayed pixels unless the signal readout time per unit pixel is reduced. For example, if signal readout of a solid-state image pickup apparatus having 2,000 pixels in both horizontal and vertical directions is to be performed at the same signal readout time per unit pixel as a solid-state image pickup apparatus having 640 pixels horizontally, 480 pixels vertically and a frame rate of {fraction (1/60)} sec., its frame rate is ({fraction (1/60)})×(2,000×2,000)/(640×480)=0.22 sec. Such frame rate necessitates an exceedingly long time in adjusting the angle of view and focal point of the taking lens even when the above described solid-state image pickup apparatus is used as an image input apparatus of a still camera system for taking still images. An inconvenience is caused when manipulating the system.
SUMMARY OF THE INVENTION
In view of the above problems of the conventional solid-state image pickup apparatus, it is a main object of the present invention to provide a high-definition solid-state image pickup apparatus capable of performing readout of the pixel signals corresponding to a full angle of view at a rapid frame rate even when the number of pixels is very large.
In accordance with the present invention, there is provided a solid-state image pickup apparatus including a pixel section having a plurality of pixels arrayed in both or one of horizontal and vertical directions and a scanning circuit for scanning the pixel section, the scanning circuit comprises a scanning section having a plurality of scanning circuit units each consisting of a shift register unit and a signal select unit having a plurality of output terminals, and a scan control section for generating scan control signal for controlling the signal select unit. Output signal of the shift register unit is selectively outputted to the plurality of output terminals of the signal select unit controlled by the scan control signal to form scanning signal of the scanning circuit.
In this manner, output signal of the shift register unit is selectively outputted to the plurality of output terminals of the signal select unit controlled by the scan control signal to form scanning signal. It is thereby possible to perform at a rapid frame rate readout of pixel signals corresponding to a full angle of view even when a high-definition solid-state image pickup apparatus having a very large number of pixels is used. The above main object is thereby achieved.
In one aspect of the invention, the signal select unit includes a plurality of 2-input NOR circuits each having one input terminal to which scan control signal is inputted and the other input terminal connected in common to which output signal of the shift register unit is applied. Scanning signal is provided from the respective output terminal of the plurality of 2-input NOR circuits. In another aspect, the signal select unit includes a plurality of 2-input NAND circuits each having one input terminal to which scan control signal is inputted and the other input terminal connected in common to which output signal of the shift register unit is applied. Scanning signal is provided from the respective output terminal of the 2-input NAND circuits. In yet another aspect, the signal select unit includes a plurality of scanning signal transmitting switches one end of each connected in common to the output terminal of the shift register unit and controlled by scan control signal, a non-select level line for supplying non-select level of the scanning signal, and a plurality of non-select switches disposed between the other end of the scan signal transmitting switches and the non-select level line and controlled by an inverted signal of the scan control signal. Scanning signal is provided from the other end of each scanning signal transmitting switch. By constructing the signal select unit in the manner as described above, it is possible to readily form
Kazama Satoshi
Mizoguchi Toyokazu
Armstrong Westerman & Hattori, LLP
Garber Wendy R.
Tillery Rashawn N.
LandOfFree
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