Driving apparatus for solid state image sensors including a sweeping action controller

A driving apparatus for solid state image sensors used for an electronic still camera for taking a still picture with a solid state image sensor, and adapted to generate timing pulses for carrying out an exposure operation of the solid state image sensor and reading electric charges occurring in a light receiving portion of the solid state image sensor due to the exposure of the film. A device generates timing pulses for carrying out the exposure and reading operations of the solid state image sensor. A sweeping action controller in the timing pulse generating device makes when a predetermined voltage is applied from the outside thereto a timing pulse for sweeping the electric charges, which are accumulated in the light receiving element in the solid state image sensor, to the outside. The predetermined voltage is applied to the sweeping action controller before the starting of the exposure operation to carry out an operation of sweeping out the electric charges in the solid state image sensor.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a driving apparatus for solid state image 
sensors, which is used for an electronic still camera. 
2. Description of the Prior Art 
A solid state image sensor, such as a CCD is used as a light receiving 
element for an electronic still video camera. An electronic still video 
camera of this kind is adapted to convert optical information into an 
electric signal and store the resultant electric signal on an information 
recording medium, such as a video floppy. Accordingly, this video camera 
is advantageous unlike a silver halide film camera in that it does not 
require developing and is capable of transferring image information to a 
remote area. 
In order to drive a solid state image sensor in such an electronic still 
camera, carrying out a photographing operation (including the exposing of 
a film and the transferring of electric charges) corresponding to one 
field or one frame only may meet the purpose unlike the case of a video 
camera. Unnecessary electric charges also occur in the light receiving 
element of CCD even before the starting of a practical exposure action. 
The generation of such electric charges is noticeable, especially, during 
an operation of an electronic shutter. Therefore, it is necessary that the 
unnecessary electric charges be swept out prior to the starting of the 
exposure. 
A shutter button consists normally of a two-step push switch including S1, 
S2 (not shown), and is constructed so that S1 is turned on when the switch 
is pressed lightly, and so that both S1 and S2 are turned on when the 
switch is pressed deep. When S1 is turned on, a controlling microcomputer 
sends out instructions for the auto-focusing (AF), exposure controlling 
(AE) and sweeping of unnecessary electric charges to a range finding 
circuit, a photometric circuit and the solid state image sensor driving 
apparatus, respectively. The instructions for AF, AE and sweeping of 
unnecessary electric charges are sent out in repetition periodically until 
S2 has been turned on. When S2 is turned on, the microcomputer gives out 
an instruction for the exposure controlling to the solid state image 
sensor driving apparatus. 
However, it is necessary in the above structure that the microcomputer has 
a special port for giving out an instruction for the sweeping of 
unnecessary electric charges. It is also necessary that the microcomputer 
directly gives out an instruction for sweeping out unnecessary electric 
charges with the instructions for AF and AE while S1 of the shutter button 
is pressed. Since the instruction for sweeping out the unnecessary 
electric charges is given out with the instructions for AE and AF, no 
problems arise in a regular case. However, when the operations are timed 
in a certain manner with an exposure instruction given out in a stage in 
which an unnecessary electric charge sweeping instruction has not yet been 
given out, unnecessary electric charges remain on the light receiving 
element in the solid state image sensor. Consequently, the unnecessary 
electric charges and the electric charges occurring due to the exposure 
are mixed to cause the quality of the image to decrease. 
Such an electronic still camera is constructed so that it is suitable to 
take still pictures one by one. Namely, a horizontal synchronizing signal 
(H.sub.SYNC) is reset (H reset) at the exposure starting time and the 
exposure finishing time. When the exposure and reading are carried out 
alternately and continuously under such conditions, H.sub.SYNCs become 
discontinuous due to the resetting thereof, so that the image on the 
picture frame of the monitor is disarranged and not clearly seen. Such 
continuous exposure/reading operations are carried out when regulation and 
evaluation are made but, unless the image on the picture frame of the 
monitor becomes stable, regulation and evaluation cannot be made. 
Such an electronic still camera is to take photographs continuously at a 
high speed in some cases. During such a continuous photographing 
operation, time is needed to sweep out unnecessary electric charges, 
expose a film and record the information, and these actions are repeated, 
so that there is a limit to the improving of the continuous photographing 
speed. Therefore, the continuous photographing speed cannot be improved 
satisfactorily. It is also necessary in a high-speed continuous 
photographing operation to synchronize the driving of the solid state 
image sensor with the rotating of the video floppy, and much time is spent 
in carrying out this operation. 
FIGS. 14A-14G are timing charts for the operations of a driving apparatus 
for a solid state image sensor, which is used in a conventional electronic 
still camera. These timing charts are based on a case where a frame 
interline CCD is used. A case where the exposure of a film is carried out 
initially with a signal which is obtained by the exposure read out 
thereafter will be described. 
In order to set the phases of rotation of the solid state image sensor 
driving apparatus and video floppy in agreement with each other, the 
resetting [the H resetting (the resetting of a horizontal synchronizing 
signal) and the V resetting (the resetting of a vertical synchronizing 
signal) ] is done (FIGS. 14D and 14E .circle.1 ) 7H (horizontal scanning 
period) after the rising of the rear end of a PG pulse consiting of a 
reference signal of the rotation of the video floppy. As a result, the PG 
pulse is changed from a high level to a low level and passed through a 
gate, so that a H resetting signal and a V resetting signal are formed. 
The falling of a trigger signal designates (FIG. 14A .circle.2 ) the 
starting of exposure, and a high-speed transfer pulse is generated 
immediately thereafter in a .phi. I signal (FIG. 14B), which is one of CCD 
image area drive pulses to sweep out the unnecessary electric charge on a 
vertical transfer portion of the solid state image sensor. A sensor gate 
(SG) pulse (FIG. 14B .circle.3 ) is then generated in the .phi.I signal 
to sweep out the unnecessary electric charge on a light receiving element 
in the solid state image sensor by the high-speed transfer pulse. Then, 
the electric charge is accumulated in the light receiving element by a SG 
pulse .circle.3 '. The rising of the trigger signal designates (FIG. 14A 
.circle.4 ) the stopping of the exposure, and a high-speed transfer pulse 
is generated immediately thereafter in the .phi.I signal to sweep out the 
electric charge generated on a vertical transfer passage for the solid 
state image sensor. The signal charges accumulated in the light receiving 
element are then transferred (FIG. 14B .circle.5 ) to a storage portion 
by the high-speed transfer pulse, after the electric charge of the light 
receiving element is transferred to V-CCD by the sensor gate pulse. 
Accordingly, the time between .circle.3 ' and .circle.5 is used 
practically as an exposure period. Then, the PG pulse is changed to a low 
level at the following SG pulse in the two SG pulses and passed through 
the gate, so that a H resetting pulse and a V resetting pulse are formed. 
As has been described above, the resetting is done again so that 
V.sub.SYNC occurs 7 H after the rise of the rear edge of the PG pulse 
(FIGS. 14D and 14E .circle.6 ). Then, the reading of the electric charges 
generated due to the exposure from the solid state image sensor is started 
at the instant .circle.7 , so that the signal read is recorded in a 
recorder 3. 
If the exposure is completed near a period V.sub.SYNC even in the case 
where the operations timed as mentioned above are carried out, an image 
cannot be outputted from the solid state image sensor. Specifically, if 
the period of the high-speed transfer pulse between .circle.4 and 
.circle.5 in FIG. 14 overlaps the period V.sub.SYNC and a period of 10 H 
direct before the V.sub.SYNC the start .circle.7 of the signal reading 
may not be carried out properly, because a signal reading pulse generating 
circuit cannot be effected suitably when the period of the high-speed 
transfer pulse between .circle.4 and .circle.5 overlaps a counting in 
a V counter which becomes a standard of generation of V.sub.SYNC. 
Therefore, it is necessary that a system controlling microcomputer in the 
electronic still camera constantly monitors SYNC signals to control the 
operations so that the exposure is not completed during the period 
V.sub.SYNC. Consequently, if the operations are timed in a certain manner, 
the waiting time occurs, so that the starting and finishing of exposure 
cannot be done at the desired time. Due to this waiting time, the 
continuous photographing speed cannot be increased. 
The necessity that the resetting is done before and after exposure to match 
the phases of rotation of the solid state image sensor driving apparatus 
and video floppy also proves to be troublesome. 
In order to photograph an object by using this kind of electronic still 
video camera with a strobe operated, it is necessary for the following 
reasons that the exposure be controlled with a high accuracy. In the case 
where CCD is used, a bright portion of an image is whitened if the 
exposure has exceeded an optimum level even slightly, and a dark portion 
of the image blackened if the exposure has become lower even slightly than 
the optimum level. In the case where a conventional silver halide film is 
used, an image formed thereon can be corrected during the development or 
printing even when the exposure deviates a little from an optimum level. 
Accordingly, in a conventional silver halide still camera, an exposure 
control operation can be carried out comparatively simply (called 
flashmatic control) by initially determining a distance of an object by an 
auto focusing means (automatic focus regulating means) on the basis of the 
equation, Guide number=Distance.times.Aperture, and then determining 
aperture on the basis of the same equation. Moreover, the distance may be 
set in eight steps with respect to the range of .infin. (infinite point)-1 
m. 
In the case of an electronic still camera using CCD as a light receiving 
element, an optimum exposure control operation cannot be carried out by 
the flashmatic control method as mentioned above since the latitude of the 
CCD is narrow. Therefore, it is necessary in the electronic still camera 
that the exposure be controlled with a high accuracy. For example, a 
method of controlling the rate of emission of a light regulating strobe in 
use is employed. 
FIG. 15 is a block diagram of an exposure control system for a conventional 
electronic still camera. When a strobe control signal (emission starting 
signal) is inputted into an emission controller 41, the emission 
controller 41 operates a strobe 42 to emit light therefrom. When the light 
is emitted from the strobe 42, an object 43 is irradiated therewith, and a 
reflected light from the object 43 enters a light receiving element 45 
through a light receiving lens 44. In an integrating circuit 46, a 
photoelectrically converted output from the light receiving element 45 is 
integrated simultaneously with the emission of light from the strobe 42. 
When an output from the integrating circuit 46 has reached a light 
regulating level which is determined by the sensitivity of CCD and a 
selected aperture, a stop signal is applied from a comparator 47 to the 
emission controller 41. Consequently, the emission controller 41 stops the 
light emitting action of the strobe 42. 
FIG. 16 is a graph showing the conversion characteristics of the rate of 
emission of the strobe in this exposure ontrol system. Referring to FIG. 
16, the longitudinal axis represents the light quantity of the strobe and 
the lateral axis time t. At an instant t.sub.1, a strobe control signal is 
generated, and the quantity of light of the strobe increases suddenly as 
shown in FIG. 16. When an integrated value from the integrating circuit 46 
has reached a light regulating level at an instant t.sub.s, the emission 
of light from the strobe 42 stops. The hatched portion between these 
instants of this graph represents an actual quantity of the emitted light. 
A broken line in FIG. 16 is an emission curve of the strobe 42 with 
respect to the time in which the light is fully emitted. Let t.sub.2 equal 
an instant at which the quantity of the emitted light becomes zero. An 
exposure control system in which t.sub.s is earlier than t.sub.2 can be 
suitably used. 
A solid state image sensor having an photo sensor, a transfer unit and a 
gate for transferring the accumulated electric charges in the photo sensor 
to the transfer unit may employ a method of regulating exposure by setting 
variable a period in which the gate is turned on, applying a gate pulse to 
the gate when a proper exposure has been attained, to turn on the gate, 
and reading out the accumulated electric charges in the photo sensor. 
The strobe in use consists, for example, of a xenon tube. In order to 
control exposure by interrupting the emission of light from the strobe 42 
as shown in FIG. 16, the construction of the circuit in the emission 
controller 41 becomes very complicated, and a difference occurs between 
the time at which an emission stopping signal is outputted and that at 
which the emission of light practically stops. Therefore, it is difficult 
to turn off the strobe with a high accuracy in the midst of the emission 
of light therefrom, and, especially, it is very difficult to turn off the 
strobe with a high accuracy in a rising part of the emission of light 
therefrom. Consequently, a photograph obtained in a photographing 
operation using even an automatically light regulating strobe with an 
aperture opened, especially, for the object near the camera, has a 
whitened image in many cases. Moreover, due to the complicated circuit 
structure, the dimensions of the system increases to cause the 
manufacturing cost of the apparatus becomes high. 
In a method of regulating exposure by changing the time at which a pulse is 
applied to a gate in a solid state image sensor having a photo sensor, a 
gate and a transfer unit, a pulse for turning on the gate is applied 
thereto at an instant at which a proper exposure is attained, to read the 
signal charges. Accordingly, the controlling of the exposure during the 
time in which the exposure is in a proper level is done reliably. However, 
since the object is positioned in the distance, a proper exposure is not 
attained in some cases. In order to prevent this, it is necessary that a 
system controlling microcomputer outputs an emission stopping signal. This 
makes it necessary to carry out a control operation using a special port 
provided in the microcomputer, and causes the construction of the 
apparatus and an exposure control operation to become complicated. 
SUMMARY OF THE INVENTION 
The present invention has been developed in view of these points, and an 
object of the present invention is to provide a driving apparatus for 
solid state image sensors, capable of reliably carrying out the sweeping 
of the unnecessary electric charges in a solid state image sensor until 
the starting of the exposure. 
The driving apparatus for solid state image sensors according to the 
present invention solving the above-mentioned problems is used for an 
electronic still camera for taking a still picture with a solid state 
image sensor, and adapted to generate timing signals for carrying out an 
exposure operation of the solid state image sensor and reading electric 
charges occurring in a light receiving portion of the solid state image 
sensor due to the exposure of the film, the apparatus being provided with 
a means for generating timing signals for carrying out the exposure and 
reading operations of the solid state image sensor, and a sweeping action 
controller adapted to control the generation of a timing signal for 
sweeping the electric charges, which are accumulated in the light 
receiving element in the the solid state image sensor, when a 
predetermined voltage signal is applied from an external system control 
circuit, the predetermined voltage being applied to the sweeping action 
controller before the starting of the exposure operation to carry out an 
operation of sweeping out the electric charges in the solid state image 
sensor. 
In the driving apparatus for solid state image sensors according to the 
present invention, the predetermined voltage is applied to the sweeping 
action controller before the starting of the exposure operation, to make 
in the timing signal generating means the timing signal for the electric 
charge sweeping operation, and carry out the sweeping of the electric 
charges accumulated in the light receiving element in the solid state 
image sensor. 
A further object of the present invention is to provide a driving apparatus 
for solid state image sensors, having a simple construction and capable of 
carrying out exposure and reading operations alternately and successively 
without resetting a synchronizing signal generating means. 
The driving apparatus for solid state image sensors according to the 
present invention is used for an electronic still camera, and adapted to 
generate timing signals for carrying out an exposure operation of a solid 
state image sensor and its operation of reading electric charges occurring 
in a light receiving element in the solid state image sensor due to the 
exposure of the film, the apparatus being provided with a means for 
generating timing signals for carrying out the exposure and electric 
charge reading operations of the solid state image sensor, and a 
controller for making in said timing signal generating means timing 
signals for the exposure and reading operations alternately field by field 
when a predetermined voltage is applied from the outside thereto, the 
apparatus being constructed so that the exposure and electric charge 
reading operations of the solid state image sensor are carried out 
alternately in succession by applying the predetermined voltage to this 
controller. 
In this driving apparatus for solid state image sensors according to the 
present invention, the controller is adapted to control the timing signal 
generating means so that the exposure and the reading of electric charges 
are carried out alternately in succession. 
A further object of the present invention is to provide a driving apparatus 
for solid state image sensors, which is capable of improving the 
continuous photographing speed. 
The driving apparatus for solid state image sensors according to the 
present invention capable of solving the above-mentioned problems is used 
in an electronic still camera for taking a still picture with a solid 
state image sensor, and adapted to generate timing signals for carrying 
out an exposure operation of the solid state image sensor and reading 
electric charges occurring in a light receiving portion of the solid stat 
image sensor due to the exposure of the film, the apparatus being provided 
with a means for generating timing signals for carrying out the exposure 
and reading operations of the solid state image sensor, and a sweeping 
action controller for generating in said means a timing signal for 
sweeping out the electric charges accumulated in the light receiving 
portion of the solid state image sensor, the apparatus being constructed 
so that the sweeping of the unnecessary electric charges in the light 
receiving element and vertical transfer unit in the solid state image 
sensor is done when the exposure for a first shot during a high-speed 
continuous photographing operation is started, and so that the sweeping of 
the unnecessary electric charges in at least one of the light receiving 
element and vertical transfer unit is omitted when the exposure for second 
and subsequent shots is started. 
In the driving apparatus for solid state image sensors according to the 
present invention, the sweeping action controller is adapted to control 
the timing signal generating means so that the sweeping of the unnecessary 
electric charges in the light receiving element and vertical transfer unit 
in the solid state image sensor is done when the exposure for a first shot 
during a high-speed continuous photographing operation is started, and so 
that the sweeping of the unnecessary electric charges in at least one of 
the light receiving element and vertical transfer unit is omitted when the 
exposure for second and subsequent shots is started. 
Another object of the present invention is to provide a driving apparatus 
for solid state image sensors, capable of starting and finishing exposure 
at desired times. 
The driving apparatus for solving the above-mentioned problems is adapted 
to generate a timing signal and a synchronizing signal for an exposure 
operation of a solid state image sensor and its operation of reading an 
electric charge occurring due to the exposure, and provided with a means 
for generating horizontal and vertical synchronizing signals, a means for 
generating timing signals for the exposure and reading operations of the 
solid state image sensor, and a means for resetting the synchronizing 
signal generating means in accordance with a reference signal applied 
thereto from the outside, the reset means being constructed so that it 
resets the synchronizing signal generating means for the vertical 
synchronizing signal after the completion of the exposure operation of the 
solid state image sensor, the synchronizing signal generating means being 
constructed so that it generates a vertical synchronizing signal at only a 
predetermined time after it has been reset, and a horizontal synchronizing 
signal alone in a period other than the vertical synchronizing signal 
generating period. 
In this driving apparatus for solid state image sensors according to the 
present invention, the reset means is adapted to reset the synchronizing 
signal generating means after the completion of the exposure operation of 
the solid state image sensor, and the synchronizing signal generating 
means generates the vertical synchronizing signal after the resetting has 
been done. In a period other than the predetermined time after resetting, 
the horizontal synchronizing signal alone is generated. 
A further object of the present invention is to provide a driving apparatus 
for solid state image sensors, having a simple construction, capable of 
accurately regulating an exposure when a strobe is turned on, and having 
exposure control functions capable of reliably finishing the exposure even 
when proper exposure is not attained. 
The driving apparatus for solid state image sensors, adapted to take 
pictures with strobe light by driving a solid state image sensor is 
provided with a photo sensor adapted to generate an electric charge when 
it receives light, a vertical transfer unit adapted to vertically transfer 
the electric charge generated in the photo sensor, a horizontal transfer 
unit adapted to horizontally transfer the electric charge from the 
vertical transfer unit to output the same to the outside, and a gate 
disposed between the photo sensor and the vertical transfer unit and 
capable of being switched to an ON-state or an OFF-state, the apparatus 
having a means for starting an exposure after the electric charges 
accumulated in the photo sensor have been transferred to the vertical 
transfer unit, a means for giving instructions to turn on a strobe on the 
basis of a predetermined shutter speed after the lapse of a predetermined 
period of time, a first exposure ending means for turning on the gate when 
proper exposure has been attained in the midst of an emission of light 
from the strobe and transferring signal charges occurring in the photo 
sensor to the vertical transfer unit to finish the exposure, and a second 
exposure ending means for turning on the gate after the emission of light 
from the strobe has been completed and transferring the signal charges 
occurring in the photo sensor to the vertical transfer unit to finish the 
exposure. 
In this driving apparatus for solid state image sensors according to the 
present invention, the strobe is turned on a predetermined period of time 
after the starting of the exposure of the photo sensor in the solid state 
image sensor, and the gate is turned on by the first exposure ending means 
when the exposure has reached a predetermined level, to finish the 
exposure. When proper exposure is not attained in spite of the emission of 
light from the strobe, the gate is turned on by the second exposure ending 
means after the completion of the emission of light from the strobe, to 
finish the exposure. 
The above and other objects and characteristics of the present invention 
will now be described with reference to the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 is a block diagram showing an example of the construction of an 
embodiment with its peripheral parts of the present invention. Referring 
to FIG. 1, a reference numeral 1 denotes a solid state image sensor 
adapted to generate an image signal when an exposure of a film is carried 
out, 2 a signal processing circuit adapted to convert an image signal from 
the solid state image sensor 1 into a projected image signal in accordance 
with a synchronizing signal, such as SYNC and BLK, 3 a recorder adapted to 
record a projected image signal on a video floppy in accordance with a REC 
gate pulse, and 4 a system control circuit adapted to control various 
parts collectively and generate a trigger pulse and a PG gate pulse in 
accordance with an operation of a shutter button 5. This system control 
circuit 4 contains a microcomputer, and generates and controls various 
kinds of pulses. The shutter button 5 consists of a two-step push switch 
including S1 and S2 (not shown), wherein S1 is turned on when it is 
pressed lightly, and both S1 and S2 are turned on when it is pressed 
deeply. A reference numeral 11 denotes a solid state image sensor driving 
apparatus adapted to apply a driving pulse to the solid state image sensor 
1, 12 an oscillator adapted to generate a reference signal, 13 a driving 
pulse generating circuit adapted to produce a driving pulse on the basis 
of the reference signal, 14 a frequency divider adapted to produce a 
signal of a horizontal scanning frequency (f.sub.H) on the basis of the 
reference signal, 15 a V-counter adapted to produce a signal of a vertical 
scanning frequency (f.sub.V) on the basis of the f.sub.H signal, 16 a 
V-shifter adapted to produce a plurality of f.sub.V signals of different 
phases on the basis of the f.sub.V signal, 17 a decoder adapted to produce 
a synchronizing signal, 18 a H-shifter adapted to produce a plurality of 
f.sub.H signals of different phases on the basis of the f.sub.H signal, 
19, 20 a HS shifter and a HS-counter, respectively, adapted to produce 
high-speed transfer (HS) signals for the solid state image sensor 1 on the 
basis of the reference signal, and 21 a HS decoder. The reference letter 
HR or VR shown above the parts 14-18 denote a terminal to which the 
H-reset signal or the V-reset signal is applied. The H-reset signal and 
V-reset signal are generated when an operation is carried out 
synchronously with the recorder 3. A reference numeral 22 denotes a reset 
circuit adapted to receive the PG pulse and the trigger pulse and produce 
the H-reset signal and a V-reset signal, 23 a gate through which only a 
first PG pulse generated after the completion of exposure is passed. This 
gate 23 is reset by a PG gate pulse from the system control circuit 4 and 
the execution of the exposure, so that when the PG gate pulse is a high 
level only a first PG pulse generated after the resetting is passed and 
when the PG gate pulse is a low level no PG pulse is passed. 24 a circuit 
for detecting an edge of the PG pulse which has passed through the gate 
23, and 25 a circuit for producing the H-reset signal on the basis of the 
edge of the PG pulse or the trigger pulse, 26 a circuit for producing the 
V-reset signal. Although the connection for supplying the H-reset signal 
and the V-reset signal is omitted in FIG. 1, these signals are applied to 
the parts 14-18 as mentioned above. A reference numeral 27 denotes a 
shutter control circuit adapted to produce a shutter control signal for 
controlling the exposure on the basis of the trigger pulse outputted from 
the system control circuit 4, 28, 30 a .phi.I system decoder and .phi.S 
system decoder adapted to produce a solid state image sensor driving 
signals (.phi.I1.about.4, .phi.S1.about.4) on the basis of the HS signal, 
f.sub.H signal and f.sub.V signal, 29 a .phi.SG system decoder adapted to 
produce exposure starting and finishing signals (SG signals) for the solid 
state image sensor on the basis of the f.sub.H signal, f.sub.V signal and 
shutter control signal, 31 a drive circuit adapted to amplify the output 
signals from the decoders 28, 29, 30 and supply the resultant signals as 
driving signals to the solid state image sensor, 32 a sweeping control 
circuit adapted to control the generation of a driving pulse for the 
sweeping of the solid state image sensor 1 in accordance with an 
instruction from the system control circuit 4. 
FIG. 2 is a flow chart showing the operational condition of the 
microcomputer contained in the system control circuit 4. The outline of an 
operation of the electronic still camera will now be described with 
reference to FIGS. 1 and 2. 
The microcomputer monitors (Step .circle.1 ) S1 in the shutter button 5 as 
to whether it is pressed. If S1 is not operated for 10 minutes (Step 
.circle.2 ), the power source is automatically turned off (Step .circle.3 
). When S1 is turned on, the recording condition of the video floppy in 
the recorder 3 is checked (step .circle.4 ). If all the tracks in the 
video floppy have been recorded, the recording cannot be done any more, so 
that the power source is turned off (Step .circle.3 ). If an unrecorded 
track is still left, instructions to carry out the automatic exposure 
regulation (AE: Step .circle.5 ) and the automatic focusing (AF: Step 
.circle.6 ) are given to the photometric circuit and range finding 
circuit. In this stage of the operation, S1 and S2 in the shutter button 
are monitored (Steps .circle.7 and .circle.8 ) as to whether they are 
pressed. If S2 is in an OFF-state, the order of procedure is returned to 
Step .circle.1 . When both S1 and S2 are turned on, the photographing 
mode is checked (Step .circle.9 ) whether it is a high-speed continuous 
photographing mode. If the photographing mode is not a high-speed 
continuous photographing mode, an instruction to carry out a high-speed 
sweeping of the electric charges in the solid state image sensor 1 is 
given (Step .circle.10 ) to the driving apparatus 11. This high-speed 
sweeping operation is applied first to the electric charges on the 
vertical transfer unit in the solid state image sensor 1, and then to 
those on the light receiving elements. When the high-speed sweeping 
operation has been completed, an instruction to carry out the exposure is 
given (Step .circle.11 ). When the exposure has been finished, a 
recording instruction is given (Step .circle.12 ) to the recorder 3, and, 
when the recording has been finished, an instruction to feed the tracks on 
the recording head of the recorder is given (Step .circle.13 ). When 
these operations have been completed, the order of procedure is returned 
to Step .circle.1 . In order to carry out a high-speed continuous 
photographing operation, the recording condition of the video floppy is 
judged (Step .circle.14 ). If the video floppy is judged to be in 
inadequate condition, power is shut off (Step 3); if the video floppy is 
judged to be suitable an instruction to carry out the recording during a 
high-speed photographing operation is given (Step .circle.15 ). The 
sweeping operation of the solid state image sensor 1 during this recording 
operation is different from that in a regular case. This operation will be 
described in detail later. If S2 is in an ON-state after the completion of 
the recording (Step .circle.16 ) and track feeding (Step .circle.17 ) 
operations, the Steps .circle.14 - .circle.17 are repeated. 
FIG. 3 is a flow chart showing the details of an exposure operation carried 
out while pictures are taken continuously at a high speed. In order to 
carry out a high-speed continuous photographing operation, the 
photographing condition is checked (Step .circle.1 ) whether a shot to be 
now taken in a first shot, and, if it is a first shot, a PSW pulse for 
controlling the sweeping of electric charge is set to a L-level. A trigger 
pulse RTRIG for determining the exposure time is then outputted (Step 
.circle.6 ). If the shot to be now taken is a second shot, the data 
corresponding to the pulse width of the RTRIG are set (Step .circle.4 ) 
shorter by t, and a PSW pulse to a H-level (Step .circle.5 ), and a RTRIG 
is then outputted (Step .circle.6 ). The sweeping control circuit 32 is 
operated so as to omit the sweeping operation for at least one of the 
receiving element and the vertical transfer unit at the exposure starting 
time when the PSW pulse has attained a H-level. When third and subsequent 
shots are taken, a RTRIG shorter by t is outputted. The purpose of 
reducing the pulse width of RTRIG for the second and subsequent shots by t 
as mentioned above is to set the substantial exposure time in this case 
equal to that in the case where a first shot is taken, because the 
sweeping (which takes a period of time t) of V-CCD on the solid state 
image sensor 1 for a photographing operation in the former case is 
omitted. Specifically, in the continuous photographing operation the light 
receiving element or V-CCD is transferred by the preceeding shot, so that 
the light receiving element or V-CCD has no unnecessary electric charge 
and accordingly the sweeping can be omitted in case of the continuous 
photographing operation. 
FIGS. 4A-4D are time charts showing the waveforms of signals generated 
during a high-speed continuous photographing operation. A high-speed 
continuous photographing operation will now be described with reference to 
FIGS. 1-3 and 4A-4D. 
When the shutter button 5 is pressed deep (both S1 and S2 are turned on), a 
trigger signal from the system control circuit 4 falls (FIG. 4A .circle.1 
), and an instruction to start exposure is given to the shutter control 
circuit 27. At the same time, a H-reset pulse HR is generated in the 
circuit 25, and the H-resetting with respect to a horizontal synchronizing 
signal H.sub.SYNC is done practically. The electric charge sweeping pulses 
are then generated (in a period A in FIGS. 4B and 4C)in a .phi.I pulse 
from the .phi.I system decoder 28 and .phi.S pulse from the .phi.S system 
decoder 30, and the electric charges on the vertical transfer unit V-CCD 
in the solid state image sensor 1 are swept out. The electric charges 
sweeping pulses then occur (in the period B in FIGS. 4B and 4C) in the 
.phi.I and .phi.S pulses, and the unnecessary electric charges on the 
light receiving element in the solid state image sensor 1 are swept out. 
This sweeping operation (in the periods A and B in FIG. 4C) is identical 
with that (Step .circle.10 in FIG. 2) carried out before a regular 
exposure operation. When a predetermined period of exposure time has 
elapsed, or, when proper exposure has been attained, a trigger signal 
rises (FIG. 4A .circle.4 ), and an exposure stopping instruction is 
given. At this time, a H-reset pulse HR is generated in the circuit 25, 
and the H-resetting with respect to the horizontal synchronizing signal 
HSYNC is done practically. The electric charges accumulated on the 
vertical transfer unit V-CCD in the solid state image sensor are swept out 
in a period C. A high-level sensor gate (SG) pulse occurs (FIG. 4B 
.circle.5 ) in the .phi.I pulse immediately after this sweeping operation, 
and the electric charges accumulated on the light receiving element in the 
solid state image sensor are transferred to the storage unit. Accordingly, 
the period between .circle.3 and .circle.5 is an actual exposure 
period. 
The H-resetting and V-resetting by a PG pulse from the recorder 3 are then 
done so that V.sub.SYNC occurs 7 H after the rise of the rear edge of the 
PG pulse constituting a rotation reference signal for the video floppy. 
When a first PG pulse after the completion of the exposure is outputted 
from the recorder 3, it passes through the gate 23 due to a PG gate pulse, 
and the rise of the rear edge of the PG pulse is detected in the edge 
detecting circuit 24, a H-reset signal and a V-reset signal being produced 
in the circuits 25, 26, respectively, on the basis of what is thus 
detected. The H-reset signal is applied to the frequency divider 14 and 
H-shifter 18, and the V-reset signal to the V-counter 15, V-shifter 16 and 
decoder 17, to be reset. Accordingly, a solid state image sensor driving 
signal generated in the driving apparatus 11 becomes synchronous with the 
rotation of the video floppy in the recorder 3. 
The electric charges occurring due to the exposure and accumulated on the 
solid state image sensor 1 are then read out from the storage portion 
thereof (in the period E in FIG. 4C). The exposure of the first shot is 
completed by carrying out these operations. When it is judged as the 
continuous photographing mode or the pressing state of the release is 
detected, for example, PSW becomes a high level "H" (FIG. 4D .circle.Z ), 
which is the time for driving CCD following a second shot in the 
continuous photographing opearation. 
When the time for exposing the second shot has come, the trigger signal 
from the system control circuit 4 falls (FIG.4A .circle.6 ), and an 
exposure starting instruction is given to the shutter control circuit 27, 
so that the electric charge on the light receiving element is transferred 
to V-CCD by a SG pulse .circle.6 ' and the H-resetting is done 
practically at this time. The electric charge sweeping pulses then occur 
(in the period F in FIGS. 4B and 4C) in the .phi.I pulse from the .phi.I 
system decoder 28 and .phi.S pulse from the .phi.S system decoder 30, and 
the unnecessary electric charges on the light receiving element in the 
solid state image sensor 1 are swept out. This sweeping operation is 
applied to the light receiving element alone, and such an operation for 
the electric charges on V-CCD is omitted. When a predetermined period of 
exposure time has elapsed, or, when proper exposure has been attained, the 
trigger signal rises (FIG. 4A .circle.8 ), and an exposure stopping 
instruction is given. The H-resetting is done at this time. The electric 
charges accumulated on the vertical transfer unit V-CCD in the solid state 
image sensor are then swept out in the period G. A high-level SG pulse 
occurs (FIG. 4B .circle.9 ) in the .phi.I pulse immediately after the 
completion of this sweeping operation, and the electric charges 
accumulated on the light receiving element in the solid state image sensor 
1 are transferred at a high speed to the storage portion thereof (in the 
period H). Accordingly, the period between .circle.7 and .circle.9 is 
an actual exposure period in this case. 
The H-resetting and V-resetting by the PG pulse from the recorder 3 are 
thereafter carried out. 
The electric charges occurring due to the exposure and accumulated on the 
image sensor 1 are then read out in the period I in FIG. 4C from the 
storage portion thereof. The exposure of the second shot is completed by 
these operations. The exposure of a third and subsequent shots is carried 
out in accordance with the same timing as in the exposure of the second 
shot. 
FIGS. 5A-5D are time charts showing another example of the operation of the 
present invention. Since the operation shown in these drawings is 
substantially identical with that shown in FIG. 2, a detailed description 
will be omitted. In the example of FIG. 5, the sweeping operations with 
respect to both the light receiving element and V-CCD, which are carried 
out in the previously-described example at the time of starting the 
exposure of second and subsequent shots, are omitted. Therefore, it is 
necessary that a RTRIG pulse for second and subsequent shots be shortened 
by 2 t (the light receiving element sweeping time and V-CCD sweeping 
time). 
As mentioned above, since a part of the sweeping operation at the time of 
starting the exposure of second and subsequent shots during a high-speed 
continuous photographing operation is omitted, the time other than the 
actual exposure time becomes shorter. This enables a continuous 
photographing speed (number of shots/sec) to be increased. 
As described in detail above, because a part of the electric charge 
sweeping operation for second and subsequent shots during a high-speed 
continuous photographing operation is omitted in the above embodiment of 
the present invention when it is judged as the second and subsequent shots 
in the high-speed continuous photographing operation, the time other than 
the actual exposure time can be shortened, and the continuous 
photographing speed can be increased. Accordingly, a driving apparatus for 
solid state image sensors, which is capable of increasing the continuous 
photographing speed, can be obtained. 
FIGS. 6A-6J are time charts showing examples of signals outputted from 
still another embodiment of the solid state image sensor driving apparatus 
11 according to the present invention and its peripheral parts. Referring 
to these time charts, FIG. 6A shows a trigger pulse applied from a system 
control circuit 4 to a shutter control circuit 27, FIG. 6B a sweeping 
control pulse applied from the system control circuit 4 to a sweeping 
control circuit 32, FIGS. 6C-6F .phi.I1-I4 pulses for driving a light 
receiving element (image area) in a solid state image sensor 1, and FIGS. 
6G-6J .phi.S1-.phi.S4 pulses for driving an accumulator (storage area) in 
the image sensor 1. What are shown in FIG. 6 correspond to the condition 
in which S2 in a shutter button is also put to an ON-state after S1 
therein was already turned on. 
The operation of this embodiment will now be described with reference to 
FIG. 1 and FIGS. 6A-6J. 
Suppose that the shutter button 5 is pressed lightly to cause S1 alone to 
be turned on. At this time, the sweeping control pulse (FIG. 6B) from the 
system control circuit 4 is in a high level. Accordingly, the .phi.I 
decoder 28, .phi.SG decoder 29 and .phi.S decoder 30 generate pulses for 
driving the solid state image sensor 1 (the period A in FIGS. 6C-6J). 
Accordingly, the electric charges (unnecessary electric charges) occurring 
on the image sensor 1 are swept out. During this sweeping operation, a 
line shift pulse, that is, a pulse for shifting by one scannning line in a 
horizontal scanning period or by one pixel portion in the vertical 
direction in CCD is utilized to read out and sweep out such electric 
charges at the end of each field period. 
When the shutter button is pressed deep (both S1 and S2 are turned on, the 
sweeping control pulse (FIG. 6B) from the system control circuit 4 falls 
(FIG. 6B .circle.1 ), and the above-mentioned sweeping operation stops. 
At substantially the same time, the trigger signal TRIG falls (FIG. 6A 
.circle.2 ), and an exposure starting instruction is given to the shutter 
control circuit 27. At this time, a H-reset pulse HR is generated in the 
circuit 25, and the H-resetting with respect to a horizontal synchronizing 
signal HSYNC is carried out. A high-speed transfer pulse is then generated 
(in the period B in FIG. 6C) in the .phi.I1-4 pulses from the .phi.I 
system decoder 28, and the unnecessary electric charges on a vertical 
transfer unit V-CCD in the solid state image sensor 1 are swept out A 
high-speed transfer pulse and SG pulse (in the period C in FIGS. 6C and 
6E) are thereafter generated in the .phi.I1 and .phi.I3 pulses, and only 
the high-speed transfer pulse is generated in the other .phi.I2 and 
.phi.I4, so that the unnecessary electric charges accumulated on the light 
receiving element in the image sensor 1 are swept out separately with 
respect to different fields. A high-speed transfer pulse and SG pulse (the 
period D and .circle.3 in FIGS. 6C and 6E) are further generated in the 
.phi.I1 and .phi.I3 pulses, and only the high-speed transfer pulse is 
generated in the other .phi.I2 and .phi.I4, so that the unnecessary 
electric charges on the light receiving element in the image sensor 1 are 
swept out simultaneously with respect to the two fields. When a 
predetermined exposure time has elapsed, or, when proper exposure has been 
attained, the trigger signal rises (FIG. 6A .circle.4 ), and an exposure 
stopping instruction is given. At this time, an H-reset pulse HR is 
generated in the circuit 25, and the H-resetting with respect to a 
horizontal synchronizing signal HSYNC is carried out. The unnecessary 
electric charges accumulated on the vertical transfer unit V-CCD in the 
solid state image sensor during the exposure time are then swept out 
during the period E. A SG pulse occurs (FIG. 6C .circle.5 ) in the .phi.I 
pulse immediately after the completion of this sweeping operation, and the 
electric charges accumulated on the light receiving element in the image 
sensor 1 are transferred to the accumulator therein. Accordingly, the 
period between .circle.3 - .circle.5 is an actual exposure period. 
The H and V-resetting operations by a PG pulse from the recorder 3 are then 
carried out so that VSYNC appears 7 H after the rise of the rear edge of 
the PG pulse constituting the rotation reference signal for the video 
floppy. 
When a first PG pulse after the completion of the exposure is outputted 
from the recorder 3, it passes through the gate 23 owing to the PG pulse, 
and the edge (rising part of the rear edge of) the PG pulse is detected by 
the edge detecting circuit 24, a H-reset signal and a V-reset signal being 
produced in the circuits 25, 26, respectively, on the basis of what is 
thus detected. The H-reset signal is applied to the frequency divider 14 
and the H-shifter 18, and the V-reset signal to the V-counter 15, the 
V-shifter 16 and the decoder 17, and these parts are reset. Therefore, a 
solid state image sensor driving signal occurring in the image sensor 
driving apparatus 11 due to these resetting operations is synchronous with 
the rotation of the video floppy in the recorder 3. 
The electric charges occurring due to the exposure then start being read. 
The signal thus read is processed in the signal processing circuit 2 and 
then supplied to the recorder 3. At the same time, a REC gate pulse is 
applied to the recorder 3. The recording is thereby done on the video 
floppy by the recorder 3. 
The solid state image sensor driving apparatus 11 is provided with a 
terminal (control terminal) used to receive a predetermined voltage from 
the system control circuit 4 during a sweeping operation. This 
predetermined voltage consists of a special voltage from the system 
control circuit 4, and can be substituted by a trigger pulse. Also, the 
sweeping can be stopped automatically in accordance with an inputted 
trigger pulse with this predetermined voltage left as it is. 
As described above, the electric charge sweeping operation (in the period A 
in FIG. 6) prior to the starting of the exposure can be carried out simply 
by merely applying a predetermined voltage to the sweeping control circuit 
32. Accordingly, the operation of the microcomputer in the system control 
circuit 4 can be simplified, and the sweeping of the unnecessary electric 
charges can also be done reliably. Therefore, the quality of an image 
formed by the exposure does not lower. 
According to this embodiment of the present invention described in detail 
above, the electric charge sweeping operation can be carried out before 
the exposure has been started, by merely applying a predetermined voltage 
to the sweeping control circuit. This enables the operation of the 
microcomputer in the system control circuit to be simplified, and the 
unnecessary electric charge sweeping operation to be carried out reliably. 
Accordingly, a solid state image sensor driving apparatus capable of 
reliably sweeping the unnecessary electric charges accumulated until the 
starting of the exposure can be obtained. 
FIG. 7 shows a block diagram showing the construction of a further 
embodiment of the present invention. In FIG. 7, the parts similar to those 
in FIG. 1 are designated by the same reference numerals and detailed 
descriptions of said parts will be omitted. 
However, the shutter control circuit 27 in FIG. 7 is a still mode shutter 
control circuit, in which a still picture is taken. 
A continuous still mode shutter control circuit 33 adapted to produce a 
shutter control signal for carrying out the still mode exposure and 
reading alternately and continuously, and a video mode shutter control 
circuit adapted to control the exposure in a video mode are provided 
instead of the sweeping control circuit 32 in FIG. 1. The solid state 
image sensor driving apparatus 11 consists of a gate array. 
FIG. 8A to 8J are time charts showing examples of signals from the image 
sensor driving circuit 11 and its peripheral parts. Referring to this time 
chart, FIG. 8A represents a trigger pulse supplied from the system control 
circuit 4 to the shutter control circuit 27, FIG. 8B one of compound 
pulses consisting of a .phi.I pulse generated in the .phi.I system decoder 
28 and a SG pulse generated in the .phi.SG system decoder 29, FIG. 8C one 
of .phi.S pulses generated in the .phi.S system decoder 30, FIG. 8D a PG 
pulse supplied from the recorder 3, FIG. 8E a compound synchronizing 
signal CSYNC consisting of H.sub.SYNC' V .sub.SYNC' FIG. 8F a composite 
blanking (CBLK) pulse, and FIG. 8G a PG gate pulse for passing the PG 
pulse through the PG gate 23. When this PG gate pulse is in a high level, 
only a first PG pulse generated after the completion of an exposure 
operation shall be effective. FIG. 8H represents a REC gate pulse showing 
the time at which the recording is done by the recorder 3, FIG. 8I a 
H-reset pulse produced in the circuit 25, and FIG. 8J a V-reset pulse 
produced in the circuit 26. 
The operation of the embodiment will now be described with reference to 
FIG. 7 and time charts of FIGS. 8A-8J. The system control circuit 4 is on 
standby for an operation of pressing the shutter button 5. In this stage 
(before the shutter button 5 is operated) of operation, the V-resetting is 
not done even when a PG pulse appears (FIG. 8A .circle.2 ). At this time, 
the PG gate pulse is in a high level (FIG. 8G), but an exposure operation 
has not yet been completed, so that the PG pulse cannot pass through the 
gate 23. Accordingly, neither the H-resetting nor the V-resetting is done, 
and V.sub.SYNC is not generated in a CSYNC signal. 
If the shutter button 5 is pressed in this condition, a trigger signal from 
the system control circuit 4 falls to give an exposure starting 
instruction (FIG. 8A .circle.2 ) to the shutter control circuit 27. At 
this time, a H-reset pulse HR is outputted (FIG. 8I) from the circuit 25, 
and the H-resetting with respect to a horizontal synchronizing signal 
H.sub.SYNC is carried out. A high-speed transfer pulse occurs immediately 
after the completion of the H-resetting operation in a .phi.I pulse (FIG. 
8B) from the .phi.I decoder 28 to sweep out the unnecessary electric 
charges on the vertical transfer unit in the solid state image sensor 1. A 
SG pulse (FIG. 8B .circle.3 ) thereafter occurs in the .phi.I signal to 
sweep out the unnecessary electric charges on the light receiving element 
in the solid state image sensor 1 by the high-speed transfer pulse. Then, 
an electric charge is accumulated on the light receiving element by the SG 
pulse .circle.3 '. When a predetermined exposure time has elapsed, or, 
when proper exposure has been attained, the trigger signal rises, and an 
exposure stopping instruction is given (FIG. 8A .circle.4 ). At this 
time, a H-reset pulse HR occurs (FIG. 8I) in the circuit 25, and the 
H-resetting with respect to the horizontal synchronizing signal H.sub.SYNC 
is carried out. A high-speed transfer pulse is generated (FIG. 8B 
.circle.5 ) in the .phi.I signal immediately after the completion of these 
resetting operations, and the electric charges occurring on the light 
receiving element in the solid state image sensor are swept out. 
Accordingly, the period between .circle.3 - .circle.5 is the actual 
exposure period. The H-resetting and V-resetting operations in accordance 
with a PG pulse from the recorder 3 are then done (FIG. 8D, 8I and 8J 
.circle.6 ) so that a V.sub.SYNC appears 7 H after the rise of the rear 
edge of the PG pulse constituting the rotation reference signal for the 
video floppy. 
When a first PG pulse after the completion of the exposure has been 
outputted (FIG. 8D .circle.7 ) from the recorder 3, it passes through the 
gate 23, and the edge (rising part of the rear edge of the pulse) of the 
PG pulse is detected in the edge detecting circuit 24. A H-reset pulse and 
a V-reset pulse are produced in the circuits 25, 26, respectively, on the 
basis of what is thus detected. The H-reset pulse is applied to the 
frequency divider 14 and H-shifter 18, and the V-reset pulse to the 
V-counter, V-shifter 16 and decoder 17, so that these parts are reset. 
Therefore, a solid state image sensor driving signal generated in the 
driving apparatus 11 due to these resetting operations becomes synchronous 
with the rotation of the video floppy in the recorder 3. 
At a later predetermined instant (in the case shown in FIGS. 8A to 8J, 9H 
after the rise of V.sub.SYNC), the reading of the electric charges 
accumulated due to the exposure is started. After the signal thus read has 
been processed in the signal processing circuit 2, it is applied to the 
recorder 3. A REC gate pulse, which is risen at the same time with the 
fall of PG pulse and fallen 3H after the following PG pulse is applied to 
the recorder 3. Consequently, the signal from the signal processing 
ciucuit 2 is recorded on the video floppy in the recorder 3 while the REC 
gate pulse is in a high level "H". In a conventional apparatus of this 
kind, such a REC gate pulse is controlled by a microcomputer in a system 
control circuit 4 but, when a microcomputer having certain performance and 
a certain clock frequency are employed a sufficiently high accuracy cannot 
be obtained. In this embodiment, the REC gate pulse is therefore 
controlled by the shutter control circuit 27 in the driving apparatus 11. 
Accordingly, the accuracy of the embodiment is improved as compared with 
that of a conventional apparatus. 
When the recording of pulses on the recorder 3 has been completed, the 
magnetic head of the recorder 3 is transferred to the next track to 
standby ready for a subsequent operation. The driving pulses (plunger 
driving pulse and stepping motor driving pulse) for this purpose are also 
generated in the solid state image sensor driving apparatus 11. These 
driving pulses may be outputted immediately after the REC pulse is 
stopped. If this control operation is carried out by the driving circuit 
11, the system control circuit 4 becomes able to control the operation of 
the shutter during this time, so that the continuous photographing speed 
increases. 
Since the vertical synchronizing signal V.sub.SYNC is generated after the 
completion of the exposure by carrying a V-resetting operation only after 
the completion of the exposure, the exposure starting and ending time do 
not coincide with the generation of V.sub.SYNC' and the waiting time, 
which occurs in a conventional apparatus of this kind, at the exposure 
starting and ending time does not occur. Accordingly, the exposure can be 
started and ended at an arbitrary time. Therefore, there is not the 
possibility that a moment to take a good picture is missed. Since the 
waiting time is eliminated, the continuous photographing speed increases. 
In the above embodiment of the present invention described in detail above, 
the resetting by a PG pulse is done after the completion of the exposure 
so as to generate a vertical synchronizing signal V.sub.SYNC. Therefore, 
the starting and finishing of an exposure operation do not coincide with 
the generation of the signal V.sub.SYNC' and the waiting time, which 
occurs in a conventional apparatus of this kind, for the exposure starting 
and ending operations does not occur. This enables a solid state image 
sensor driving apparatus capable of starting and finishing the exposure at 
an arbitrary time to be obtained. 
FIGS. 9A-9F and 10A-10F are time charts showing examples of the signals 
from a further embodiment of the solid state image sensor driving 
apparatus 11 according to the present invention and its peripheral parts. 
Out of these time charts, FIGS. 9A-9F show an even (second) field , and 
FIGS. 10A-10F an odd (first) field which is immediately after the field of 
FIGS. 9A-9F. 
Referring to these time charts, FIGS. 9A and 10A show a synchronizing 
(SYNC) signal from a decoder 17, FIGS. 9B and 10B a blanking (BLK) pulse 
from the decoder 17, FIGS. 9C and 10C one of .phi.I pulses generated in a 
.phi.I system decoder 28, FIGS. 9D and 10D one of .phi.S pulses generated 
in a .phi.S system decoder 29, FIGS. 9E and 10E a S blanking (SBLK) pulse 
from the decoder 17, and FIGS. 9F and 10F an exposure time control (SEC) 
pulse from a system control circuit 4. 
The operation of the embodiment in a continuous still mode will now be 
described with reference to FIGS. 7, 9A-9F and 10A-10F. 
When a continuous still mode is selected by a mode selecting switch (not 
shown) in the system control circuit 4, a SEC pulse of a predetermined 
voltage is applied from this circuit 4 to a continuous still mode shutter 
control circuit 33. Consequently, this shutter control circuit 33 controls 
the .phi.I system decoder 28-.phi.S system decoder 30 so that a timing 
signal for making the solid state image sensor 1 carry out exposure and 
reading operations alternately and continuously is generated. 
At an instant .circle.1 in the second field of FIG. 9, the SEC pulse 
(FIG. 9F) from the continuous still mode shutter control circuit 33 falls, 
and an exposure starting instruction is given to the .phi.I system decoder 
28-.phi.S system decorder 30. A high speed transfer pulse for sweeping the 
unnecessary electric charges on the vertical transfer unit is generated 
(FIGS. 9C and 9D .circle.2 ) in the .phi.I pulse and .phi.S pulse. When 
this sweeping operation has been completed, high-speed transfer pulses 
(FIGS. 9C and 9D .circle.3 ) for sweeping the unnecessary electric 
charges on the light receiving element occur in the .phi.I pulse and 
.phi.S pulse. Therefore, the exposure actually starts at the instant of 
generation of the last SG pulse of H-level at the rear end of FIG. 9C and 
9D .circle.3 . The electric charges are thereafter accumulated due to the 
exposure on the light receiving element in the solid state image sensor 1. 
The exposure is continuously carried out, and, at the instant in FIG. 10A 
.circle.4 . the second field terminates and the first field starts. The 
unnecessary electric charges on the vertical transfer unit are swept out 
(FIGS. 10C and 10D .circle.6 ) for the preparation of the reading of 
electric charges. The SEC pulse rises (FIG. 10F .circle.5 ) within the 
vertical blanking period to give an instruction to finish the exposure. 
The finishing of the exposure is set so that it is carried out within the 
vertical blanking period. When the sweeping (FIGS. 10C and 10D .circle.6 
) of the vertical transfer unit is finished, the electric charges 
occurring in the light receiving element in the solid state image sensor 1 
due to the SG pulse are transferred (FIGS. 10C and 10D .circle.7 ) to the 
storage unit thereof. The electric charges are then read out from the 
storage unit in the image sensor 1 at a video rate. These electric charges 
are converted into projected image signals in a signal processing circuit 
2, and a photographed image is displayed on a monitor provided outside. 
When the signal reading (FIGS. 10A-10F) described above for the first field 
is finished, the exposure shown in FIG. 9F is carried out repeatedly in 
the subsequent field. Namely, exposure and reading operations are carried 
out alternately in succession for 1/30 sec for each operation. The 
H-resetting is not done at the exposure starting and ending time so that 
the image on the TV monitor is not disturbed. 
As described above, the exposure and reading operations are carried out 
alternately in succession for the two fields separately by merely applying 
a predetermined voltage from the system control circuit 4 to the 
continuous still mode shutter control circuit 33 in the solid state image 
sensor driving apparatus 11. Further, since the H-resetting is not done at 
the exposure starting and ending time unlike a case where pictures are 
taken in a regular still mode, a stable synchronizing signal can be 
obtained when an image is outputted. 
Needless to say, when a still mode is selected, the still mode shutter 
control circuit 27 control a regular still mode photographing operation, 
and, when a video mode is selected, the video mode shutter control circuit 
34 controls a video mode photographing operation. 
In this embodiment described in detail above of the present invention, the 
exposure and reading operations are carried out alternately in succession 
for each field independently by merely applying a predetermined voltage 
from the system control circuit 4 to the solid state image sensor driving 
apparatus 11. Accordingly, a solid state image sensor driving apparatus of 
a simple construction capable of carrying out the exposure and reading 
operations continuously without carrying out a H-resetting operation can 
be obtained. 
FIG. 11A is a block diagram showing an example of the construction of a 
further embodiment of the present invention. Referring to the drawing, a 
reference numeral 42 denotes a strobe adapted to emit light in accordance 
with a strobe control signal, 1 a solid state image sensor, 51 a photo 
sensor, which is adapted to accumulate electrical charges when it receives 
light, in the solid state image sensor, 52 a gate adapted to be turned on 
and off by a pulse supplied from the outside so as to transfer the 
electric charges occurring in the photo sensor to a vertical transfer unit 
which will be described later, 53 a a vertical transfer unit adapted to 
transfer the electric charges passed through the gate 52 and accumulated 
on the photo sensor 51, 54 a horizontal transfer unit adapted to 
horizontally transfer the electric charges sent from the vertical transfer 
unit 53 and send out the same as output signals, and 55 a sweeping drain 
to which the unnecessary electric charges accumulated up to the exposure 
starting time are swept out at the exposure starting time. A reference 
numeral 56 an image sensor driving circuit adapted to apply driving 
signals to the vertical and horizontal transfer units 53, 54 in the solid 
state image sensor 1, and gate 52, 57 a photometric circuit adapted to 
determine the exposure and send the photometric level to a system control 
circuit 58, which will be described later, and image sensor driving 
circuit 56, 58 a system control circuit adapted to control various parts, 
59 a signal processing circuit adapted to process an output signal from 
the image sensor 1 and apply the resultant signal to a recorder therein, 
and 60 a recorder adapted to record a signal applied from the signal 
processing circuit 59 on a medium consisting of a disk. 
FIG. 11B is a flow chart showing the outline of the operation of this 
embodiment of the present invention. The present invention is directed to 
a driving apparatus for a solid state image sensor provided with a photo 
sensor, a gate and transfer units, characterized in that the exposure is 
started (Step .circle.1 ) in the photo sensor, a strobe being turned on 
(Step .circle.2 ) after the lapse of a predetermined of time, the 
exposure being monitored (Step .circle.3 ) as to whether it attains a 
predetermined level, the time being monitored (Step .circle.4 ) as to 
whether a predetermined period of time has elapsed after the emission of 
light from the strobe, the gate being turned on when the exposure has 
attained a predetermined level, or, when a predetermined period of time 
has elapsed after the emission of light from the strobe to transfer the 
accumulated electric charges on the photo sensor and finish (Step 
.circle.5 ) the exposure. 
FIGS. 12A-12E are time charts showing the details of driving signals for 
driving the solid state image sensor by this embodiment of the driving 
apparatus according to the present invention. Referring to these time 
charts, trigger pulses TRIG1, TRIG2, a strobe control signal and .phi.V 
(only one thereof is shown in FIG. 12E) are produced in the image sensor 
driving circuit 56. Out of these pulses, the trigger pulse TRIG1 is a 
pulse fed from the system control circuit 58 for setting the time of 
exposure based on the regular light, and the trigger pulse TRIG2 a pulse 
obtained by shaping the waveform of an exposure control signal supplied 
from the photometric circuit 57 or the system control circuit 58 when the 
exposure by the light from the strobe has attained a proper level. The 
image sensor driving circuit 56 is adapted to produce a transfer pulses 
.phi.V, apply these transfer pulses to the vertical transfer unit 53 and 
gate 52 and carry out the transferring of the electric charges from the 
photo sensor 51 to the vertical transfer unit 53 through the gate 52, and 
from the vertical tranfer unit 53 to the sweeping drain 55 or horizontal 
transfer unit 54. The first and second SG pulses having an amplitude up to 
the H-level of the transfer pulses .phi.V are sensor gate (SG) pulses for 
turning on the gate 52. 
The operation of the solid state image sensor driving apparatus will now be 
described by using these timing charts. The gate 52 is turned on by the 
first SG pulse in the transfer pulse .phi.V, and the unnecessary electric 
charges accumulated on the photo sensor up to this time are transferred to 
the vertical transfer unit 53. These electric charges are swept out to the 
sweeping drain 55 by the high-speed transfer pulse in .phi.V by the time 
the second SG pulse has been outputted. When the gate 52 is turned off, 
i.e., when the first SG pulse falls, the photo sensor 51 generates 
electric charges due to the receiving of the light, and continues to 
accumulate them thereon. 
After the TRIG1 rises, a strobe operating trigger signal is generated (FIG. 
12C .circle.3 ), and the strobe starts emitting light. When proper 
exposure has attained in the midst of the emission of light from the 
strobe , an exposure finishing pulse occurs (FIG. 12B .circle.4 ) in 
TRIG2. Consequently, the second SG pulse occurs (FIG. 12E .circle.4 ) in 
.phi.V. When proper exposure is not attained (exposure finishing pulse 
does not occur in TRIG2) in the midst of the emission of light from the 
strobe, the second SG pulse occurs (FIG. 12E .circle.5 ) a predetermined 
period of time (about 300-500 microseconds) after the instant 3 . 
As described above, when the second SG pulse occurs, the gate 52 is turned 
on, and the electric charges accumulated on the photo sensor 51 are sent 
to the vertical transfer unit 53. The pulses on the vertical transfer unit 
are then sent to the horizontal transfer unit by the .phi.V pulse, the 
resultant pulses being sent to the outside. 
FIG. 13 is a block diagram of a SG pulse generating portion of the image 
sensor driving circuit. 
Referring to the drawing, a reference numeral 61 a fall detecting circuit 
adapted to detect the falling of a trigger pulse 1 which substantially 
corresponds to the exposure time, 62 a circuit adapted to generate a first 
SG pulse after the occurrence of the falling of the pulse detected by the 
fall detecting circuit 61, 63 a circuit adapted to detect the rise of the 
first SG pulse, 64 a delay circuit adapted to delay the trigger pulse 1 by 
a predetermined period of time after the rise, which was detected by the 
rise detecting circuit 63, of the same pulse 1, 65 a circuit for detecting 
the falling of the trigger pulse 2 which is obtained by shaping the 
waveform of the exposure control signal outputted from the photometric 
circuit 57 or the system control circuit 58 when the exposure attains a 
proper level, 66 a circuit for generating the second SG pulse in 
accordance with the falling detected by the fall detecting circuit 65 and 
an output from the delay circuit 64, 67 a .phi.SG decoder adapted to 
generate the first and second SG pulses on the basis of the instructions 
from the first and second SG pulse generating circuits 62, 66, and 68 a 
circuit adapted to generate a strobe control signal, by which the light is 
emitted from the strobe simultaneously with the rise of the trigger pulse 
1 detected by the rise detecting circuit 63. 
These circuits enable the first SG pulse to be generated, and the second SG 
pulse to be also generated in the midst of the emission of light from the 
strobe or a predetermined period of time after the starting of the 
emission of light from the strobe. Accordingly, since the exposure 
finishes even when proper exposure is not attained, the regulation of 
exposure during the use of the strobe in the present invention can be 
carried out reliably as compared with that under the same conditions in a 
conventional apparatus of this kind, the burden on the microcomputer in 
the system control circuit 58 becomes small. 
In this embodiment described in detail above of the present invention, the 
gate is turned on when proper exposure is attained during the emission of 
light from the strobe and after the termination of the emission thereof to 
send the electric charges occurring on the photo sensor to the vertical 
transfer unit and finish the exposure. Therefore, a solid state image 
sensor driving apparatus of a simple construction capable of regulating 
the exposure accurately during the emission of light from the strobe, and 
having the exposure control functions by which the exposure operation can 
be finished reliably even when proper exposure is not attained can be 
obtained.