JPH06311433A - Method for driving solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve picture quality in large light quantity especially by eliminating the transfer remaining of smear electric charge for the electric charge discharging period of the vertical CCD of an FIT type image pickup element. CONSTITUTION:In the method for driving a solid-state image pickup device where a light receiving part having vertical CCD arranged in plural arrays, a storage part composed of vertical CCD continuous to each vertical CCD and a horizontal CCD connected to the vertical CCD of the storage part are provided and the vertical CCD of each array in the light receiving part is connected to plural light receiving elements, a signal reading period (3), a frame shift period (4), a light shift period (1) and a discharging period (2) are provided, and the transfer speed in the light receiving part is made to be faster than the transfer speed of the storage part for the line shift period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device using a CCD, and more particularly to a driving method for performing charge transfer.

[0002]

2. Description of the Related Art As a solid-state image pickup device using a CCD, a frame transfer (FT) is available.
Or FIT: Frame Interline Tr
An image sensor of the transfer type (hereinafter referred to as FIT type image sensor) is used. In this FIT type image pickup device, the light received by the light receiving section is photoelectrically converted according to the amount of the light to generate a signal charge, which is transferred to the storage section and further transferred to the reading section for output. in this case,
CC for the CCD register of the light receiving unit or the storage unit
If an excessive amount of charge that exceeds the amount of charge handled by the D register is injected, normal transfer is not performed and transfer remains. For this reason, when a high-luminance object is imaged by the FIT type image pickup device, signal charges remain in the CCD register due to residual transfer, and this becomes a noise signal and is superimposed on the subsequent original signal charges, and the image is significantly deteriorated. . This point will be described in more detail below.

FIG. 9 shows a planar structure of the FIT type image pickup device 1. The FIT type image pickup device 1 has a light receiving portion 2 and a storage portion 3, and the light receiving portion 2 includes light receiving elements 4 (four in each row in this example) arranged in an array in a plurality of rows and each light receiving element 4. On the other hand, it is composed of a vertical CCD (V-CCD) 6 provided for each column via a read gate (ROG) 5. The storage unit 3 is a vertical CCD connected to the V-CCD 6 of the light receiving unit 2.
(V-CCD) 7. V-C of storage unit 3
The horizontal CCD (HC
CD) 8 is provided. Therefore, the H-CCD 8 is connected to the V-CCD 6 of the light receiving section 2 via the V-CCD 7 of the storage section 3.

Further, in contact with the H-CCD 8, the V-CCD
Smear gate for smear sweeping (SM
G) 9 and smear drain 10 are arranged, and a floating diffusion amplifier 11 for converting a charge signal into a voltage signal, a reset transistor 12, and an output buffer 13 are provided at the output side end of the H-CCD. .

In the following description, for simplification of description, each of the V-CCDs 6 and 7 has a pulse IM1 to pulse 1 to be described later.
4 and ST1 to 4, four-phase driving is performed, the number of pixels is four vertical pixels, and the reading method is non-interlaced operation.

FIG. 10 shows V- along the line XX 'in FIG.
The structure of the vertical section of the CCD portion is shown. In addition, FIG.
The conventional drive waveform of a T type image sensor is shown. In FIG. 10 and FIG. 11, IM1 to 4 represent four-phase electrodes for driving the V-CCD 6 of the light receiving unit 2, and ST1 to 4 are V- of the storage unit 3.
A four-phase electrode for driving the CCD 7 is shown. As shown in FIG. 10, four gate electrodes corresponding to IM1 to ST4 and ST1 to ST4 are V- of the light receiving section 2 and the storage section 3, respectively.
It becomes a structural unit of CCDs 6 and 7, and is shown by U1 and U2 in the figure, respectively.

As shown, a common silicon substrate 15
An oxide film 16 made of SiO ₂ is formed thereon, and an electrode 17 made of polysilicon is formed thereon. Each electrode 1
7 is sequentially connected to each of the four-phase electrodes IM1 to 4 and ST1 to 4 for introducing the drive pulse described above. In this example, it is assumed that an n-channel CCD is formed on the silicon substrate 15. Therefore, a potential well is formed at a high gate potential level. Dashed line 18
Indicates this potential well. In the example of FIG. 10, IM
A high-level potential is applied to the portions connected to 1, 2, and ST1, 2, and a low-level potential is applied to the portions connected to IM3, 4 and ST3, 4.

Next, the drive pulse waveform for controlling the drive of the V-CCD will be described with reference to FIG. V-CCD
Drive pulse consists of four periods ,,,
Indicates the driving period of the H-CCD. Is a line shift period, is a sweep period, is a read period, and is a frame shift period. The driving waveforms of the V-CCDs 6 and 7 of the light receiving unit 2 and the storage unit 3 have the same waveform except the reading period. In the line shift period, one cycle of the V-CCD is driven for each horizontal scanning period. This is an operation corresponding to the vertical scanning of TV. During the H-CCD driving period of this line shift period, the V-CC of the light receiving unit 2 is
The photons leaking into D6 are photoelectrically converted in the V-CCD and accumulated as a noise signal.

This noise is a smear signal, and in order to remove this noise charge from the V-CCD, the V-CCD is driven at a high speed during the sweeping period, and the V-C of the light receiving section 2 is driven.
The smear charges in the CD 6 are transferred to the storage section 3. Therefore, at the end of the sweep-out period, the V-CCD of the light receiving unit 2
There is almost no smear charge in 6. At this time, the smear charge originally stored in the storage unit 3 is H-
It is swept out to the smear drain 10 via the CCD 8 and the smear gate 9.

In this way, the signal charges are read out from the light receiving element 4 and stored in the clean V-CCD 6 from which the smear noise component has been swept.

Next, during the frame shift period, V-
V-CCD of the light receiving part 2 by driving CCDs 6 and 7 at high speed
The signal charge in 6 is sent to the storage unit 3 and V of the storage unit 3
-Smear charges in the CCD 7 are swept out to the smear drain 10 via the H-CCD 8 and the smear gate 9. The storage unit 3 to which the signal charges have been transferred is shielded from light and no photons are incident, so that the H-C in the next line shift period is used.
Almost no new smear is added to the signal charge during CD driving. Note that the lower part (B) of FIG. 11 shows the waveforms of the drive pulses in the line shift period, and the drive pulses IM1 to IM4 of the light receiving unit 2 and the corresponding drive pulses ST1 to ST4 of the storage unit 3 are shown. Is the same.

The above charge transfer operation is schematically shown in FIGS. These figures show the potential well 18 at times t1 to t7 (FIG. 11) that forms a transfer operation of one cycle.
(FIG. 10) shows the state of the accumulated charges. In each figure, D1 indicates a V-CCD of the light receiving portion, D2 indicates a V-CCD of the accumulating portion, D3 indicates an H-CCD, D4 indicates a smear gate, and D5 indicates a smear drain. First, FIG.
As shown in, the frame shift ends at time t1,
The charges a to d read from the four light receiving elements 4 in each column of the light receiving section 2 (FIG. 9) are sent to the V-CCD 7 of the storage section 3. During the period from t1 to t1 '(H-CCD driving period), the V-CCD is stopped, and during this period, photons leak into the V-CCD (D1) of the light receiving section (arrow E) as shown in FIG. The smear charge 19 is accumulated.

Next, at t2, since the V-CCD performs one cycle of transfer (line shift period from t1 'to t2), the signal and smear charges are in the X direction (upward in FIG. 9, FIG. 1).
To the right of 0) by the amount corresponding to the constituent units U1 and U2 (FIG. 10) of the V-CCD (arrow F). At this time, the electric charge (a) of the V-CCD 7 of the storage unit 3 from the 1st X direction is H-CC.
The electric charge is sent to D (D3) and is horizontally transferred by the H-CCD during the period of t2 to t2 '(H-CCD drive period). Further, as in the period between t1 and t1 ′, the smear charges in the horizontal transfer period from t2 to t2 ′ are superimposed, and the smear charge amount increases.

Next, during the line shift period from t2 'to t3, only one structural unit of the V-CCD is transferred (arrow F),
The state becomes the illustrated time t3 (FIG. 14).

Similarly, as shown in FIG. 15, from t3 to t
Even at 3 ', smear charge is added (arrow E), and this is t3'
Only one structural unit is transferred during the line shift period from time t4 to time t4 (arrow F). The same operation is repeated until t5 (FIG. 16). Further, smear charges are similarly accumulated in the horizontal transfer period from t5 to t5 '(arrow E), and t in FIG.
It becomes the state of 5 '. In this state, the signal charges a to d are all sent horizontally, and V-CC of the light receiving unit and the storage unit is
D is only smear charge.

Next, in the sweep period from t5 'to t6, the V-CCD is transferred at a high speed to move the smear charge of the light receiving portion (D1) to the accumulating portion and the accumulating portion ( The charges in the V-CCD of D2) are transferred at high speed to the H-CCD (D3) and are swept out to the smear drain (D5) via the smear gate (D4) (arrow H). Therefore, at t6, there is almost no smear charge in the V-CCD of the light receiving portion.

Next, in the read period from t6 to t7, the signal charges are read from the light receiving element to the V-CCD (D1), and the state of t7 in FIG. 18 is set. Further, in the frame shift period from t7 to t1, the V-CCD is transferred at high speed to move the signal charge of the light receiving portion to the storage portion (arrow J). At this time, the smear charges in the V-CCD (D2) of the storage section are simultaneously transferred to the H-CCD at high speed and swept out to the smear drain via the smear gate. The above is the description of the charge transfer state of the FIT type image pickup device.

[0018]

However, in the above-mentioned conventional FIT type image pickup device, a noise image may occur due to defective transfer of smear charges. In such an operation of the FIT type image pickup device, transfer residual is likely to occur, that is, the sweep period of FIG. 11, that is, t5 ′ to t6 of FIG.
In the V-CCD of the light receiving portion during the sweeping period.
This is because the amount of charge handled by the V-CCD tends to decrease as the transfer speed increases, and the amount of smear charge generated may exceed the amount of charge handled by the V-CCD when a high-luminance object is imaged. Since the V-CCD of the accumulating section can have a wider channel width than the V-CCD of the light receiving section (FIG. 9), the accumulating section can handle a larger amount of charge, and the transfer residual is less likely to occur in the accumulating section.

FIG. 19 shows the monitor screen 20 in the case where the transfer residue occurs. In this example, a high-luminance circular subject is imaged, and smear generated by the circular subject cannot be completely transferred from the light receiving unit to the storage unit during the sweep transfer period and is left on the upper portion of the screen. Reference numeral 21 is an image of a high-brightness subject, and reference numeral 22 is a noise image due to the residual transfer of smear charges.

20 and 21 are situation diagrams when the smear amount excessively increases between t5 'and t1 in FIGS. 17 and 18 described above. When the smear charge (arrow E) accumulated in the light receiving portion becomes excessive at t5 ′ and exceeds the charge amount handled by the V-CCD (D1) of the light receiving portion, the sweep transfer period (t5 ′ to t6) ( In the arrow G), the electric charge cannot be completely transferred from the light receiving unit to the storage unit. Therefore, at time t6, the V-CCD (D1) of the light receiving section
The smear charge remains on. As a result, the signal charges and the smear charges are mixed at the time point (t7) when the reading period is completed, which causes noise. Since the amount of this remaining amount naturally increases as the V-CCD is closer to the storage unit, noise is generated at the upper part of the screen due to the untransferred portion.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is possible to improve the image quality particularly at a large light amount by eliminating the transfer residual of smear charges during the charge sweeping period of the V-CCD of the FIT type image pickup device. To aim.

[0022]

In order to achieve the above object, in the method for driving a solid-state image pickup device according to the present invention,
A light receiving section having vertical CCDs arranged in a plurality of rows, a storage section made up of vertical CCDs continuous to each vertical CCD, and a horizontal CCD connected to the vertical CCDs of the storage section,
A method of driving a solid-state image pickup device, wherein a plurality of light receiving elements are connected to the vertical CCDs in each column of the light receiving section, and a charge storage potential well is formed in the vertical CCDs of the light receiving section and the storage section corresponding to each light receiving element. , A signal reading period in which the signal charge photoelectrically converted by the light receiving element is taken into each potential well of the vertical CCD of the light receiving section, and the signal charge of the read vertical CCD of the light receiving section is stored in the vertical CCD of the accumulating section.
Of the smear charges accumulated in the vertical CCD of the accumulating section at the same time while being transferred to each potential well of the horizontal CC.
The frame shift period of discharging via D, the charges of the potential wells of the vertical CCDs of the light receiving portion and the storage portion are sequentially transferred to the adjacent potential wells, and the charges of the potential wells of the vertical CCDs of the outermost storage portions are transferred. A line shift period for transferring to the horizontal CCD, and a smear charge accumulated in the vertical CCD of the light receiving unit after all the signal charges transferred from the light receiving unit to the storage unit by repeating this line shift period are transferred to the horizontal CCD. And a sweep-out period for transferring the data to the storage unit at a time, and the transfer speed of the vertical CCD of the light receiving unit is made faster than the transfer speed of the storage unit in each line shift period.

In a preferred embodiment, the transfer speed of the light receiving section is increased by increasing the number of times of charge transfer between the potential wells of the light receiving section during the line shift period more than the number of charge transfer between the potential wells of the accumulating section. It is faster than the transfer rate of the storage unit.

In another preferred embodiment, a solid-state image pickup device is used in which the amount of charge handled by the vertical CCD of the storage section is larger than the amount of charge handled by the vertical CCD of the light receiving section.

In still another preferred embodiment, the storage section is shielded from light, and is applied to a solid-state image pickup device in which photons leak only to the light receiving section and accumulate smear charge during a horizontal CCD driving period after each line shift period. Has been done.

[0026]

The smear charge accumulated in the light receiving portion V-CCD (vertical CCD) immediately before the sweep transfer period is reduced, and the transfer residual of the smear charge at the sweep time is prevented.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 8 show FIs according to embodiments of the present invention.
An example of the V-CCD drive waveform of the T-type image pickup device and the drive situation at that time are illustrated. Like the conventional example (FIG. 11), the drive waveform of FIG. 1 is composed of a line shift period, a sweep period, a read period, and a frame shift period, and indicates an H-CCD (horizontal CCD) drive period. Differences from the conventional example are t1 'to t2, t2' to t3, t3 'to t4, t.
It is the drive waveform of the V-CCD during the period 4 ′ to t5, that is, the drive waveform during the line shift period. An enlarged view of this drive waveform is shown in FIG. 11 (B) for the conventional example and FIG. 1 (B) for the present invention example.
It was shown to. In the example of the present invention, the change in the V-CCD drive waveform of the storage section indicated by ST1 to ST4 is similar to that in the conventional example, and vertical transfer is performed for one cycle as in the conventional example. On the other hand, IM1-
Regarding the V-CCD transfer waveform of the light receiving part indicated by IM4,
The conventional example has one cycle, whereas the example of the present invention has a transfer waveform of two cycles. Therefore, in the example of the present invention, the number of times of transfer of the V-CCD of the light receiving section during the line shift period is twice as large as that in the conventional example.

Next, the transfer situation of the V-CCD according to the drive waveform of FIG. 1 will be described with reference to FIGS. Time t in FIG.
1, the frame shift is completed, and the signal charges a to d read from the light receiving units a to d (FIG. 9) are V-C in the storage unit.
It has been sent to CD (D2). The period from t1 to t1 'is the driving period of the H-CCD, and this period is V-C.
The CD is stopped, and smear charges are accumulated in the V-CCD of the light receiving section during this time due to leakage of photons (arrow E) (FIG. 3). Next, at t1 ″, since the V-CCDs of the light receiving section and the storage section transfer for one cycle, the signal charge and smear charge are transferred in the X direction (FIG. 9) to the V-CCD structural units (U1, U2), That is, it moves by one potential well (arrow F), at which time the electric charge (a) of the V-CCD (D2) in the storage portion closest to the X direction (right side in FIG. 3) is H.
-Sent to CCD (D3). At time t2, only the V-CCD (D1) in the light receiving section further transfers for one cycle, so that the smear charges move in the X direction by the unit of the V-CCD. At this time, the storage unit is stopped,
In the potential well 20 of the V-CCD near the first light receiving section of the storage section, the smear charge newly sent from the light receiving section side is added to the smear charge originally present in the potential well. Also, as with t1 to t1 ', t2
During the period from t2 ′ to t2 ′, smear charges are added to the smear charges generated during the period from t1 to t1 ′ due to the leakage of photons into the V-CCD of the light receiving unit, resulting in the state at time t2 ′ (FIG. 4). ).

Next, in the period from t2 'to t2 ", the line shift operation (arrow F) is performed in the same manner as in the period from t1' to t1", and the electric charges of the V-CCD of the light receiving portion and the accumulating portion correspond to one constituent unit. Are transferred one by one. In this embodiment, the period from t2 ′ to t2 ″ is half the period of the entire line shift (period from t2 ′ to t3) as shown in FIG. 1 (B).

Subsequently, in the period from t2 "to t3, only the V-CCD (D1) of the light receiving portion has one structural unit (1
The transfer operation (arrow F) of the potential well) is performed. That is, during this period, as shown in FIG. 1B, only the drive pulses IM1 to IM4 of the light receiving unit are driven, and the drive pulses ST1 to ST4 of the accumulating unit are not driven. As a result, the V-
The smear charge accumulated in the CCD is shifted to the right in the figure by one unit, and the smear charge accumulated in the rightmost potential well of the light receiving part is transferred to the leftmost potential well of the accumulating part. Is added to (t in FIG. 4)
State 3).

Next, the period from t3 to t3 '(H-CCD
Driving period), from t1 to t1 ′ and t described above.
Similarly to the period from 2 to t2 ′, photons leak into the V-CCD of the light receiving portion and smear charge is added (arrow E).

Next, during the period from t3 'to t3 ", the transfer operation (arrow F) of the V-CCD of the light receiving portion and the accumulating portion is performed, and subsequently, from the time t3" to t4, the V-C of the light receiving portion is transferred.
Only the CD performs the transfer operation. As a result, the state becomes t4 in FIG.

Similarly, the H-CCD drive period from t4 to t4 'and t4' to t4 "and t4" shown in FIG.
After the line shift period from t5 to t5, the state becomes t5, and after the H-CCD driving period from t5 to t5 ', the state becomes t5' in FIG. From this t5 'state, t
During the period up to 6 (sweeping period in FIG. 1), high-speed sweeping of smear charges is performed (FIG. 7). That is, the smear charge accumulated in the V-CCD of the light receiving portion is transferred to the V-CCD of the accumulating portion at a time (arrow G), and the smear charge originally present in the V-CCD of the accumulating portion is changed to H-C.
It discharges to a smear drain through a smear gate via CD (arrow H).

The state immediately before the sweep period, that is, t
5'state, t5 'state of the conventional example (FIG. 17)
Clearly, the present invention is better than the V-CCD (D
The amount of smear charge accumulated in 1) is small. This is because, in the present invention, since only the V-CCD is transferred at a speed twice as fast as that of the conventional example during the line shift period, the amount of residual smear charge is almost half that of the conventional example. Similarly, if the transfer speed of the V-CCD of the light receiving section is increased by n times, the amount of smear charge accumulated in the V-CCD of the light receiving section becomes 1 / n of the conventional example.

On the other hand, in the example of the present invention, since the smear charge reduced from the light receiving part is transferred to the accumulating part, the smear charge of the accumulating part at time t5 'is increased as compared with the conventional example. However, the V-CCD of the accumulating section has a wider channel width than the V-CCD of the light receiving section (FIG. 9), and the channel length of the accumulating section is not limited, so that the V-CCD of the accumulating section is larger. Since the area can be set large and the amount of charge handled can be increased, it is possible to design the storage unit so that transfer residual is unlikely to occur.

Thereafter, as described above, the V-CCD is transferred at high speed from t5 'to t6 (sweeping period), and the smear charge of the light receiving portion is moved to the accumulating portion (FIG. 7).
(Arrow G), along with this, the smear charge originally present in the V-CCD of the storage section is transferred to the H-CCD at high speed and is swept out to the smear drain via the smear gate (arrow H). Therefore, at t6, there is almost no smear charge in the V-CCD of the light receiving portion.

Next, the signal charges a, b, c and d are taken into the V-CCD from the light receiving portion during the read period from t6 to t7, and V- during the frame shift period from t7 to t1.
The CCD is transferred at a high speed at one time to move the signal charges of the light receiving section to the storage section (arrow J). At this time, V-C of the storage unit
The smear charges on the CD are simultaneously transferred to the H-CCD at a high speed at the same time and swept out to the smear drain via the smear gate (arrow K). As a result, the V-CCD returns to the state at time t1. The above is the description of the operation of the embodiment of the present invention.

[0038]

As described above, the FI according to the present invention
In the T-type image pickup device driving method, the transfer speed of the V-CCD of the light receiving unit is set to the V of the storage unit during the line shift period in which the charges accumulated in the V-CCD of the light receiving unit and the storage unit are sequentially transferred in units of constituent units. -Because it is faster than the transfer rate of the CCD, the line shift operation is repeated by the number of structural units and all the signal charges in the storage section are transferred to the H-CCD and stored in the light receiving section in the state immediately before the sweep period. The smear charge amount is reduced to less than the handled charge amount. Therefore, all the charges in the light receiving portion are sent to the accumulating portion without causing transfer residual during the sweep period. Therefore, even when an image of a high-luminance object is picked up, smear charges due to photon leakage can be reliably discharged from the light receiving unit, and a noise image due to transfer remaining can be prevented from occurring, and a high-quality image can be obtained.

That is, according to the present invention, V-C of the light receiving portion is obtained immediately before the high-speed sweeping of smear charges (t5 ').
Since the smear charge amount accumulated in the CD can be 1 / n of that of the conventional example, the V- of the light receiving portion during the sweeping period (t5 'to t6) in which the transfer residual is likely to occur due to the excessive smear charge amount.
The smear charge amount of the CCD can be reduced, and the transfer residual due to the excess charge amount can be suppressed. In addition, since the same amount of smear charge as that in the conventional example is accumulated in the V-CCD of the light receiving portion with the amount of light n times that of the conventional example, the light resistance amount according to the present invention is to withstand up to n times the amount of light as the conventional example. The characteristics can be greatly improved.

Note that n in the above description is not limited to an integer. This is because the transfer speed of the light receiving unit is doubled in this example, but it is also possible to perform transfer for one and a half cycles and set n = 1.5. Further, for simplification in the above description, in the embodiment of the present invention, the V-CCD is driven by four phases, the number of pixels is four vertical pixels, and the reading method is non-interlaced operation. It is obvious that the above method may be used, the number of pixels may be any other number, and other read methods (field read interlace, frame read interlace, etc.) can be applied.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a driving method of an FIT type image pickup device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a charge storage state of the V-CCD at the end of the frame shift period according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of charge storage and transfer states of the V-CCD during the first line shift period in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of charge storage and transfer states of the V-CCD during the second line shift period according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of charge storage and transfer states of the V-CCD during the third line shift period according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram of charge storage and transfer states of the V-CCD during the fourth line shift period according to the embodiment of the present invention.

FIG. 7 is a diagram showing V- during a sweep period according to an embodiment of the present invention.
It is an explanatory view of charge storage and transfer state of CCD.

FIG. 8 is an explanatory diagram of charge storage and transfer states of the V-CCD during a frame shift period according to the embodiment of the present invention.

FIG. 9 is a plan configuration diagram of a FIT type image pickup device to which the present invention is applied.

10 is a cross-sectional configuration diagram taken along the line XX ′ in FIG.

FIG. 11 is an explanatory diagram of a conventional driving method.

FIG. 12 is an explanatory diagram of a charge storage state of a V-CCD at the end of a frame shift period for explaining a conventional driving method.

FIG. 13 is an explanatory diagram of a charge storage and transfer state of the V-CCD in the first line shift period in the conventional driving method.

FIG. 14 is an explanatory diagram of charge storage and transfer states of the V-CCD during the second line shift period in the conventional driving method.

FIG. 15 is an explanatory diagram of charge accumulation and transfer states of the V-CCD during the third line shift period in the conventional driving method.

FIG. 16 is an explanatory diagram of a charge storage and transfer state of the V-CCD during the fourth line shift period in the conventional driving method.

FIG. 17 is an explanatory diagram of charge storage and transfer states of the V-CCD during a sweep period for explaining a conventional driving method.

FIG. 18 is an explanatory diagram of charge storage and transfer states of the V-CCD during a frame shift period for explaining a conventional driving method.

FIG. 19 is an explanatory diagram of a noise image due to smear charges.

FIG. 20 is an explanatory diagram of charge storage and transfer states of the V-CCD during the sweep period for explaining the problems of the conventional technique.

FIG. 21 is an explanatory diagram of charge storage and transfer states of the V-CCD during the frame shift period for explaining the problems of the conventional technique.

[Explanation of Codes]: Line shift period ,: Sweep period ,: Read period ,: Frame shift period ,: H-C
CD drive period, D1: V-CCD of light receiving portion, D2: V-CCD of storage portion, D3: H-CCD, D4: smear gate, D5: smear drain.

Claims (4)

[Claims] 1. A light receiving section having vertical CCDs arranged in a plurality of rows, a storage section composed of vertical CCDs continuous to each vertical CCD, and a horizontal C connected to the vertical CCDs of the storage section.
A solid state in which a plurality of light receiving elements are connected to the vertical CCDs in each column of the light receiving section, and charge storage potential wells are formed in the vertical CCDs of the light receiving section and the storage section corresponding to the respective light receiving elements. In a method of driving an image pickup device, a signal charge photoelectrically converted by the light receiving element is applied to a vertical CC of a light receiving unit.
A signal reading period for taking in each potential well of D and the read signal charges of the vertical CCD of the light receiving section are transferred to each potential well of the vertical CCD of the accumulating section at once and accumulated in the vertical CCD of the accumulating section. A frame shift period in which smear charges are discharged through the horizontal CCD, charges in each potential well of the vertical CCDs of the light receiving portion and the storage portion are sequentially transferred to the adjacent potential wells, and a vertical CCD of the outermost storage portion is stored. A line shift period for transferring the charges in the potential well to the horizontal CCD, and a line shift period is repeated to transfer all the signal charges transferred from the light receiving unit to the storage unit to the horizontal CCD, and then within the vertical CCD of the light receiving unit. A sweep period for transferring the accumulated smear charges to the accumulating portion at a time, and each line shift period In a method for driving a solid-state imaging device, characterized in that the faster transfer rate of the storage unit transfer rate of the vertical CCD of the light receiving portion. 2. The transfer speed of the light receiving section is increased by increasing the number of times of charge transfer between the potential wells of the light receiving section more than the number of charge transfer between the potential wells of the storage section within the line shift period. The method for driving a solid-state image sensor according to claim 1, wherein the method is faster than the speed. 3. The method of driving a solid-state image pickup device according to claim 1, wherein the amount of charge handled by the vertical CCD of the storage unit is larger than the amount of charge handled by the vertical CCD of the light-receiving unit. . 4. The solid-state image pickup device according to claim 1, wherein the storage unit is shielded from light and is applied to a solid-state imaging device in which photons leak only to the light receiving unit during a horizontal CCD driving period after each line shift period. Driving method of the solid-state image pickup device.