JPH03147486A - Drive method for charge transfer type solid-state image pickup device - Google Patents

Abstract

PURPOSE:To drive a solid-state image pickup element not causing blooming by increasing a saturation output signal of a transfer solid-state image pickup device so as to expand the dynamic range of the image pickup device. CONSTITUTION:Let a luminous quantity made incident in a photoelectric conversion element for a storage time T be LSIG and a signal charge generated in the photoelectric conversion element by the light be QSIG, then even when the illuminance is high and the luminous quantity LSIG is large, since the storage of the signal charge is implemented by the charge transfer element, the value of the signal charge QSIG at which the signal charge starts flowing to an overflow drain is larger than a conventional value and the range of linear function relation between the signal charge QSIG and the luminous quantity LSIG is established is widened. That is, the range from which an output signal in proportional to the luminous quantity LSIG of a light made incident in the solid-state image pickup device is widened in the drive method storing the signal charge in the charge transfer element Thus, at the time when the charge transfer element is in transfer operation and the signal charge is stored in the photoelectric conversion element, blooming is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for driving a solid-state imaging device using a charge transfer element.

Conventional technology A charge transfer solid-state imaging device includes a photoelectric conversion element that converts light into signal charges, a charge transfer element that transfers the signal charges, a readout gate region that reads out the signal charges generated in the charge conversion element to the charge transfer element, and charge transfer. It consists of an output section that outputs signal charges transferred by the element. The read gate is often used as part of the transfer gate of the charge transfer element. If the read gate is also used as part of the transfer gate, the voltage applied during read operation and the voltage applied during transfer operation are different, so read and transfer can be performed independently by changing the applied voltage. .

Figures 6(a) and 6(b) show the temporal change in the readout gate voltage applied to the readout gate in a conventional charge transfer solid-state imaging device, and the occurrence in the photoelectric conversion element corresponding to the temporal change in the readout gate voltage. This figure shows how the signal charges transferred are transferred. In addition, FIGS. 7(a) and 7(b) show the read gate voltage VGI, which is applied to the read gate in FIG.
FIG. 3 is a diagram showing the potential energy of signal charges generated in a photoelectric conversion element, a read gate, and a charge transfer element when VO2 is applied.

In FIG. 6, signal charges generated by light incident on the photoelectric conversion element are accumulated in the open photoelectric conversion element for a certain period of time T, and then transferred and outputted by the charge transfer element over a certain period of time TI. At this time, T is called storage time and TI is called transfer time. The charge transfer element does not perform a transfer operation during the remaining time after subtracting the transfer time from the accumulation time. In a charge transfer solid-state imaging device of a type called a frame interline transfer type, the transfer time T+ is much smaller than the storage tank time T.

A conventional method for driving a charge transfer element will be explained in detail below. During the time T2 immediately before the charge transfer element performs a transfer operation, voltage VGI is applied to the read gate and the read gate is closed (.

At this time, signal charges are accumulated in the charging conversion element during the time period T1 and T2. At time T3 immediately before the charge transfer element performs a transfer operation, a voltage VG3 is applied to the read gate, and all signal charges generated by light in the photoelectric conversion element are read out to the charge transfer element.

T3 is usually negligibly shorter than T2. A driving method is used in which signal charges accumulated in the photoelectric conversion element for a certain period of time are transferred and outputted by a charge transfer element.

In FIG. 7(a), when a gate voltage VGI is applied to the readout gate, the potential energy immediately below the readout gate portion forms a potential well surrounding the photoelectric conversion element, and signal weighting is accumulated in this well.

After that, when gate voltage VG3 is applied to the readout gate (Fig. 7(b)), the potential of the photoelectric conversion element is the highest, and becomes lower in the order of the readout gate region and the charge transfer element (Fig. 7(b)). The signal charge moves to the side with lower potential energy and is read out to the transfer element.

Problems to be Solved by the Invention If the maximum amount of charge that can be stored in a photoelectric conversion element is QPD%, and the maximum amount of charge that can be transferred by a charge transfer device is QCOD, then
In charge transfer solid-state imaging devices, when the amount of light incident on the photoelectric conversion element is large, excess charge accumulates in the photoelectric conversion element and exceeds the potential energy barrier of the readout gate, which is closed by the applied voltage V. flowing out,
Charges flow into a charge transfer element that is transferring signal charges from another photoelectric conversion element, and mixing of signal charges occurs within the charge transfer element. This phenomenon is called blooming. In order to prevent the occurrence of blooming, an overflow drain is provided to discharge the charge excessively accumulated in the charge conversion element.

The maximum amount of charge Qpo that can be stored in the photoelectric conversion element is determined by the setting of the threshold value of the overflow drain.

In conventional driving methods, the saturation charge amount QSAT corresponding to the saturation output of the imaging device is subject to restrictions as shown in the following equation.

(1) QSAT “Qpo (QPD<QCCD
)(2) QSAT″Qcco (Qpo > Q
cco ) In other words, in conventional driving methods, the unit pixel size is required to be reduced in order to increase the number of photoelectric conversion elements, and by reducing the dimensions of the photoelectric conversion elements and charge transfer elements, the size of the charge transfer elements can be reduced. The maximum charge amount Q cco that can be transferred is the maximum charge ji that can be stored in the photoelectric conversion element
If Qpo is exceeded, the saturation charge amount QSAT of the image sensor is determined from Qpo, as shown in equation (1) above. Conversely, if the charge transfer element dimensions are reduced more than necessary compared to the photoelectric conversion element dimensions, each charge amount Qcco
<Qpo, and as shown in equation C) above, the saturation charge amount QSAT of the imaging device is determined by the maximum charge amount QccD that can be transferred by the charge transfer element, so signal charge remains transferred within the charge transfer element. do.

Therefore, in order to optimize the dimensions of each element, it is desirable that the maximum charge amount Qpo that can be stored in the photoelectric conversion element and the maximum charge amount Q cco that can be transferred in the charge transfer charge element are approximately equal. Maximum amount of charge Q that can be accumulated by the photoelectric conversion element
The PD is controlled by an overflow drain to prevent the imaging device from blooming.

However, in reality, because the threshold value of conventional overflow drains is easily influenced by design and process, it is very difficult to set Qpo to the desired value, which is the maximum amount of charge that can be stored in the photoelectric conversion element. there were.

FIG. 2 shows the relationship between LSIG, the amount of light incident on the photoelectric conversion element during the accumulation time T, and Qsla, the signal charge generated in the photoelectric conversion element by the light. Since the illuminance is low and the light amount Lsto is small, if the signal charge amount Qs+o is smaller than the maximum charge amount Qpo that can be accumulated by the photoelectric conversion element set by the overflow drain, the potential inside the photoelectric conversion element becomes the signal charge Qs+a. , and a linear relationship holds between the signal charge Qs+o and the light amount LSIG.

However, when the illuminance is high, the amount of light LSIG becomes large, so when the signal charge amount Qs+a becomes no longer negligible compared to the maximum charge amount Qpo that can be accumulated in the photoelectric conversion element, the potential in the photoelectric conversion element becomes the accumulated signal charge Qs+.

As a result, a part of the signal charge overflows to the overflow drain, and Qs+o is not proportional to LSIG.

Therefore, in the conventional driving method of accumulating signal charges in a photoelectric conversion element, the amount of light of the optical signal incident on the solid-state imaging device is
Output signal charge amount Qs+ proportional to G.

There is a problem in that obtaining the signal charge amount Qs+o is limited to a case where the signal charge amount Qs+o is sufficiently smaller than the maximum charge amount Qpo that can be stored in the photoelectric conversion element.

The present invention solves the above-mentioned conventional problems by increasing the saturation signal Qs+o of the imaging device so as not to be limited by the saturation charge amount of the photoelectric conversion element, and increasing the light amount L 5I (l and signal charge amount) of the optical signal. Expanding the linear region with Qs+a, QpoξQ
The purpose is to realize a state of cco and to minimize the waste of dimensions of each element.

Means for Solving the Problems A first step of applying a readout gate voltage for reading signal charges accumulated in a photoelectric conversion element of a charge transfer solid-state imaging device to a charge transfer element, and a step of applying a readout gate voltage to the charge transfer element; a second step of applying a gate voltage lower than the read gate voltage to transfer the first step and the second step;
The total time during which the read gate voltage is applied in the process is defined as one period.

The gate voltage may be lower than the gate voltage applied in the first step, the second step, and the first step for reading out excess signal charges accumulated in the photoelectric conversion element to the charge transfer element. a third step of applying a readout gate voltage higher than the gate voltage applied in the second step, the readout gate voltage in the first step, the second step, and the third step; The sum of the times during which the above is applied is defined as one period, and the first read gate voltage is continuously applied immediately after the read gate voltage is applied in the third step.

Furthermore, the same gate voltage as in the first step, the second step, the third step, and the second step of transferring the signal charge of the charge transfer element read out in the third step is applied. a fourth step of applying the same gate voltage as the second step of transferring signal charges to and from the first step; The sum of the times during which the readout gate voltage is applied in the step, the third step, and the fourth step is defined as one period, and the application of the readout gate voltage in the third step is the same as the time when the readout gate voltage is applied in the second step. This is performed between the voltage application and the read gate voltage application in the fourth step.

Operation In the driving method of the present invention, all or more than a certain amount of signal charges generated by light in a photoelectric conversion element over a certain period of time are accumulated in a charge transfer element. Therefore, the amount of charge accumulated in the charge conversion element is not saturated by the overflow drain.

Therefore, in conventional charge transfer solid-state imaging devices, the maximum amount of charge that can be stored in the photoelectric conversion element is a factor that limits the magnitude of the saturated output signal of the imaging device, but in the drive method of the present invention, the charge transfer The saturated output signal of a type solid-state imaging device is mainly limited only by the maximum amount of charge that can be transferred by the charge transfer element.

Further, the linear relationship between the amount of light and the amount of signal charge accumulated does not deteriorate due to a change in the potential of the photoelectric conversion element caused by the charges accumulated in the charge conversion element.

Therefore, the saturation signal amount of the imaging device is increased, and it is possible to widen the linear region between the light amount and the signal charge amount.

Embodiment FIGS. 1(a) and 1(b) show temporal changes in the transfer operation pulse of the charge transfer element and from the charge conversion element to the charge transfer element, in order to explain the first embodiment of the present invention in more detail. FIG. 3 is a schematic diagram showing temporal changes in the voltage applied to the readout gate for reading out the signal charges of FIG.

T1 is the time during which the charge transfer element performs a transfer operation, and T3 is a time during which the charge transfer element does not perform a transfer operation.

As described above, this embodiment differs from the conventional art in that signal charges always flow into the charge transfer element during time T3 when the charge transfer element does not perform a transfer operation. Therefore, the saturation characteristics can be improved by the driving method of this embodiment in a frame interline transfer type charge transfer solid-state imaging device in which the period T+ in which the charge transfer element performs a transfer operation is shorter than the period T3 in which it does not perform a transfer operation. Particularly effective.

Signal charges generated by light in the photoelectric conversion element are accumulated in the charge transfer element for a certain period of time, transferred by the charge transfer element, and output.

Assuming that the maximum amount of charge that can be accumulated in the photoelectric conversion element is Qpo, and the maximum amount of charge that can be transferred by the charge transfer element is QCCD, by performing such driving, the saturated charge '1Qshr of the imaging device is expressed by the following formula. As such, it is only limited by the maximum amount of charge Qcco that can be transferred by the charge transfer element.

(2) QSAT” Qcco (Qpo>
Qcco ) (3) QSAT ” Qcco (
Qpo < QCCD, ) In other words, as shown in equation (3), if the maximum amount of charge Qpo that can be accumulated in the photoelectric conversion element is small (
, if the maximum charge amount Q cco that can be transferred by the charge transfer device is large, the saturation characteristics of the imaging device can be improved only by changing the driving method.

The amount of light incident on the photoelectric conversion element during the accumulation time T is L.
SIG, and the signal charge generated in the photoelectric conversion element by the light is Qs+a. In the conventional driving method, when the illuminance is high and the light amount LSIG is large, the signal charge amount Qs+a cannot be ignored compared to the saturated charge amount QPD of the photoelectric conversion element (then, the potential in the photoelectric conversion element is
+a itself changes, the signal charge amount overflows to the overflow drain, and the signal charge QsIa and the light amount LSI
The linearity with G becomes worse. However, in the driving method of this embodiment, since the signal charge is accumulated in the charge transfer element, the value of the signal charge amount Qs+o at which the signal charge begins to overflow to the overflow drain is larger than that of the conventional method (signal charge amount There is a wide range in which a linear functional relationship holds between Qs+a and the light amount LSIG. In other words, in the driving method of this embodiment in which signal charges are accumulated in the charge transfer element, the range in which an output signal proportional to the amount of light Ls+a incident on the solid-state imaging device can be obtained is wider than in the conventional method.Charge transfer element During the time T1 during which the photoelectric conversion element is performing a transfer operation and signal charges are accumulated in the photoelectric conversion element, the overflow drain performs the conventional operation to suppress blooming.

Note that the time during which the voltage VG3 is applied to the readout gate in order to accumulate signal charges in the charge transfer element is an internal time period within the time period T3, even if the voltage VG3 is not continuously applied during the time period T3. It is clear that the effects of the above embodiments can also be obtained. In this case, if a constant amount of light is incident on the photoelectric conversion element, the amount of charge stored in the charge transfer element can be freely changed by changing the length of time for applying voltage VO3 to the readout gate.

Therefore, it is possible to adjust the amount of charge stored in the charge transfer element to an optimum amount so that it does not exceed the maximum amount of charge that can be transferred by the charge transfer element.

The potential energies for the signal charges generated in the photoelectric conversion element, readout gate, and charge transfer element when the readout gate voltages V (11 and VO2 in Figure 1 are applied) are shown in Figures 7 (a) and (b). The potential energy in Figure 7 shows that when forming a solid-state image sensor, the potential energy of the photoelectric conversion element is generally higher than the potential energy of the charge transfer element. It is changed and formed.

Further, the potential energy of the photoelectric conversion element is the reference energy of the potential energy of other regions, and here, the potential energy of the photoelectric conversion element when the substrate is grounded is used as the reference. In this case, it is not necessarily necessary to ground the substrate, and a reference potential energy may be set by applying an appropriate voltage to the substrate.

Furthermore, although the potential energy of the photoelectric conversion element fluctuates by back biasing the substrate, the value of the fluctuated potential energy is never lower than the potential energy of the charge transfer element.

A second embodiment will be described with reference to FIG.

FIGS. 3(a) and 3(b) show temporal changes in the transfer operation pulse of the charge transfer element and signals from the photoelectric conversion element to the charge transfer element, for explaining the second embodiment of the present invention in more detail. FIG. 3 is a schematic diagram showing temporal changes in voltage applied to a readout gate for reading charges.

Further, FIG. 4 is a diagram showing the potential energy of signal charges existing in the photoelectric conversion element, the readout gate, and the charge transfer element when the voltage VG2 shown in FIG. 3 is applied to the readout gate.

The potential energies of signal charges existing in the photoelectric conversion element, readout gate, and charge transfer element when the readout gate voltages VGI and VO2 in FIG. 3 are applied are as shown in FIG. 4.

In addition, the maximum amount of charge that can be accumulated in the photoelectric conversion element is Qpo,
Let Qcco be the maximum charge amount that can be transferred by the charge transfer device, QSAT be the saturation charge amount of the imaging device, and specifically let Q'po be the amount of signal charge that can be stored in the photoelectric conversion element with voltage VG2 applied to the readout gate.

As described above, in this embodiment, during the period when the charge transfer element does not perform a transfer operation, the signal charge accumulated in the photoelectric conversion element in excess of a certain amount Q'po is auxiliary accumulated in the charge transfer element.

The signal charge generated by light in the photoelectric conversion element is
Accumulated in the photoelectric conversion element and charge transfer element over 2 hours,
At the end of time T2, all the data are read out to the charge transfer element, and transferred and outputted by the charge transfer element at time T+.

Here, a case where TI is sufficiently smaller than T2 is shown.

By performing such driving, the same effect as the first real/flow side can be obtained. Furthermore, by comparing the background noise caused by each dark current generated in the photoelectric conversion element and the charge transfer element, it was found that the background noise of the charge transfer element was higher than the background noise of the photoelectric conversion element.
When the /N ratio becomes small, in the driving method shown in this embodiment, the illuminance is low and the amount of signal charge generated during the accumulation time is Q'
p.

When the amount is less than , signal charges are accumulated in photoelectric conversion elements with less background noise.

In order for signal charges to accumulate in the charge transfer element, which has more background noise than the photoelectric conversion element, the illuminance must be high (only when the amount of signal charge is greater than Q'po). Therefore, if the illuminance is low It is possible to achieve the low noise required for element characteristics and the high saturation signal amount required when illuminance is high, resulting in a wide dynamic range.

Note that the time for applying the voltage VO2 to the readout gate in order to accumulate signal charges in the charge transfer element does not have to be applied continuously during the time T2, but even if it is applied for a part of that time, the above implementation can be performed. The effect of the example can be obtained. In this case, the amount of charge stored in the charge transfer element can be freely changed by changing the length of time for applying voltage VO2 to the read gate. However, it is assumed that the amount of light incident on the photoelectric conversion element is constant.

Therefore, the amount of charge accumulated in the charge transfer element can be adjusted to an optimum amount so that it does not exceed the maximum amount of charge that can be transferred by the charge transfer element.

A third embodiment will be described with reference to FIG.

FIGS. 5(a) and 5(b) show temporal changes in the transfer operation pulse of the charge transfer element and signals from the photoelectric conversion element to the charge transfer element, for explaining the third embodiment of the present invention in more detail. FIG. 3 is a schematic diagram showing temporal changes in voltage applied to a readout gate for reading charges.

The potential energies for the signal charges generated in the photoelectric conversion element, readout gate, and charge transfer element when the readout gate voltages VGI N VO2 and VO2 in Figure 5 are applied are shown in Figures 7(a) and (b). That's right.

T1 is the time during which the charge transfer element performs a transfer operation to output the signal charge accumulated in the photoelectric conversion element, T2 is the time during which the charge transfer element does not perform a transfer operation, and T4 is the time during which the charge transfer element operates until time T2 ends. T3 is the time period during which the charge transfer device is operated to transfer so as to discharge the excess signal charge accumulated in the charge transfer device. It's time to read.

Similarly to the second embodiment, the maximum amount of charge that can be stored in the photoelectric conversion element is Qpo, the maximum amount of charge that can be transferred by the charge transfer device is QccD, the saturated charge of the imaging device jIQsAT,
In particular, the amount of signal charge that can be accumulated in the photoelectric conversion element with voltage VG2 applied to the read gate is defined as QPD.

Since the threshold value of a conventional overflow drain is easily influenced by the design and process, it is very difficult to set the maximum amount of charge Qpo that can be stored in the photoelectric conversion element to a desired value. However, in the driving method of this embodiment, the charge generated in the photoelectric conversion element above Qpo' is discharged at time T4, so that the charge transfer element functions as a kind of overflow drain. Therefore, in the conventional charge transfer type solid-state imaging device, which is prepared at the design stage, it is necessary to incorporate an overflow drain into the photoelectric conversion element. Furthermore, in the driving method of this embodiment, the threshold value is determined by the voltage VG2 applied to the readout gate during the time T2.
By adjusting VO2, Qpo', the amount of signal charge that can be stored in the charge transfer element, can be freely and easily controlled. Further, the threshold value itself is stable against changes in the amount of charge accumulated in the photoelectric conversion element and the charge transfer element.

Therefore, we omitted the conventional overflow drain and calculated the maximum amount of charge that can be stored in the photoelectric conversion element with the readout gate closed.
If the imaging device is manufactured so that it is thicker than cco, the voltage V applied to the readout gate (12) can be adjusted to transfer the amount of signal charge Qpo that can be stored in the photoelectric conversion element to the charge transfer element. When the maximum possible charge amount Q is set equal to the CCD, the maximum amount of charge that can be transferred by the charge transfer element can be taken out as the saturation output of the charge transfer solid-state imaging device.

Further, when a charge transfer element is used as an overflow drain, stable operation can be achieved because the threshold value of the overflow drain is determined by the voltage applied to the read gate.

Therefore, the amount of light LSIG that enters the photoelectric conversion element and the signal charge Qs+ generated in the photoelectric conversion element by the light
The linear relationship with a is such that Qs+a is so large that it cannot be ignored compared to the saturation charge amount Qpo' of the photoelectric conversion element. , the linear region between the signal charge fiQs+o and the light amount LSI(+) expands.

In the third embodiment, a case has been described in which voltage VG2 is always applied to the read gate during time T2, but in order for the charge transfer element to discharge excess charge at time T4, it is necessary to apply - within time T2. It is clear that the voltage V(II may be applied temporarily, the read gate may be closed, and the voltage VG2 may be applied to the read gate immediately thereafter.

Furthermore, in the first, second, and third embodiments, the case where there is a readout gate independent of the charge transfer element has been described, but the readout gate is a transfer gate of the charge transfer element. It is often used for some purposes (,
In this case, since the applied voltage level is different between the read operation and the transfer operation, read and transfer can be performed independently, so the read gate does not need to be independent from the charge transfer element.

In other words, here, the difference in potential energy between the charge transfer element and the readout gate is caused by the difference in the concentration of the diffusion layer when forming the solid-state image sensor, but since the readout gate also serves as the charge transfer gate, the applied readout gate voltage is Although the potential energy of the gate and the charge transfer element is lowered, the potential energy difference between the two due to the initial difference in impurity concentration is almost maintained, and the potential energy between the two is shifted by the magnitude of the potential.

Effects of the Invention As described above, according to the present invention, the magnitude of the saturated output signal of a charge transfer solid-state imaging device, which is limited by the maximum amount of charge that can be accumulated in a photoelectric conversion element in conventional driving methods, can be improved. It is possible to further increase the dynamic range of the imaging device.

In addition, even when the maximum amount of charge that can be transferred by the charge transfer element is not sufficient and as a result, the saturated output signal of the imaging device does not increase compared to when using the conventional driving method, conventionally, the photoelectric conversion element is used to generate the signal. Because of the accumulated charge, the output signal does not deviate from the linear relationship with the amount of light incident on the photoelectric conversion element before reaching the saturated output.

Note that the present invention can be applied to charge transfer solid-state imaging devices having either one-dimensional or two-dimensional configurations.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the read gate voltage and charge transfer pulse of the first embodiment of the present invention, and FIG. 2 is a diagram showing the charge transfer pulse of the first embodiment of the present invention. A diagram showing the relationship between the optical signal amount and the signal charge amount in the second embodiment; FIG. 3 #; # is a diagram showing the read gate voltage and a diagram showing the charge transfer pulse in the second embodiment of the present invention , FIG. 4 is a diagram of potential energy versus signal charge at the gate voltage applied in the driving method of the present invention, and FIG. 5 is a diagram showing the readout gate voltage and charge of the third embodiment of the present invention. A diagram showing a transfer pulse, Figure 6≠; # is a diagram showing a conventional readout gate voltage and a diagram showing a charge transfer pulse; A diagram of the potential energy of the signal charge and a diagram of the potential energy of the signal charge at the gate voltage V (13. VGI...Gate voltage that closes the readout gate, VO2...Second implementation In the example, the gate voltage applied to the read gate during the period T2, VO2...
Gate voltage when reading signal charges from the photoelectric conversion element to the charge transfer element, TI...Transfer period, T2...
...Period in which voltage VG2 is applied to the readout gate in the second embodiment, T3...Period in which signal charges accumulated in the photoelectric conversion element are read out to the charge transfer element, T4...
... Signal charge accumulated in the photoelectric conversion element is transferred to the transfer element A...Photoelectric conversion element region, B...Reading gate region, C...Charge transfer element region ,
LSIG...The amount of light of the optical signal that enters the charging conversion element, Qs+o...The amount of signal charge that can be output by the charge transfer solid-state imaging device when the optical signal enters the photoelectric conversion element, Qpo ... Maximum amount of charge that can be stored in a photoelectric conversion element, Q'po ... Maximum amount of charge that can be stored in a photoelectric conversion element, Q cco ... Transferred by a charge transfer element Maximum amount of charge possible, VGI'...Gate voltage that closes the readout gate, VO2...Second
In the embodiment, the gate voltage applied to the read gate during the period T2, VO2... The gate voltage when reading to the charge transfer element, T1... The transfer period, T2...
...Period in which the charge transfer element does not perform a transfer operation, T3
・・・・・・Period in which signal charges accumulated in the photoelectric conversion element are read out to the charge transfer element.

Claims (3)

[Claims] (1) A first gate electrode for signal readout that reads out the signal charges accumulated in the photoelectric conversion section to the charge transfer section at the readout gate electrode.
applying a gate voltage of A method for driving a charge transfer solid-state imaging device, characterized in that: (2) The first signal readout gate electrode that reads out the signal charges accumulated in the photoelectric conversion section to the charge transfer section.
applying a gate voltage of A third gate voltage lower than the first gate voltage and higher than the second gate voltage for reading is applied, and the first, second,
The total application time of the third gate voltage is set to one period,
A method for driving a charge transfer solid-state imaging device, characterized in that the first gate voltage is continuously applied immediately after applying the third gate voltage. (3) The first signal readout gate electrode that reads out the signal charge accumulated in the photoelectric conversion section to the charge transfer section.
further applying a second gate voltage lower than the first gate voltage to the read gate electrode, and applying a third gate voltage lower than the first gate voltage and higher than the second gate voltage. a fourth gate having the same voltage as the second gate voltage to which a gate voltage is applied and for transferring the signal charge of the charge transfer element section read out with the third gate voltage toward the signal sweep section; While applying the voltage, the sum of the application times of the first, second, third, and fourth gate voltages is set to one period, and the application of the third gate voltage is equal to the second gate voltage and the second gate voltage. A method for driving a charge transfer solid-state imaging device, characterized in that the method is performed between applications of a fourth gate voltage.