JPH01298879A - Drive method for charge coupled device - Google Patents

Abstract

PURPOSE:To device the method such that an electron charge is moved between a storage part and a transfer part without provision of an independent gate or the like by controlling an applied voltage to an electrode of the transfer part variably into four different voltages. CONSTITUTION:The applied voltages to the electrode of the vertical transfer CCD 2 are controlled variably into four-value voltages of H1, H0, L0 and L1. Thus the electric charge is transferred vertically in the vertical transfer CCD 2 by two values L0, M in the applied voltages to the vertical transfer CCD 2 and the electric charge is moved to the vertical transfer CCD 2 from the storage part 1a by using the other one value L1 and moved to the adjacent storage part 1a from the vertical transfer CCD 2 by using the rest one value H1. Then the electric charge is moved from the vertical transfer CCD 2 to the storage part 1a without provision of an independent gate part or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for driving a charge coupled device (hereinafter referred to as CCD) used as a solid-state image sensor in an electronic still camera or the like.

<Prior Art> A CCD is formed by arranging a large number of photoelectric conversion elements in a matrix. In an electronic still camera, an optical image from an optical lens is formed on a photoelectric conversion element of the CCD for photoelectric conversion, and the resulting charge is accumulated in an accumulation section.

Then, the charges stored in the storage section are transferred to a transfer section via a gate section and an electrode section, and then transferred to a processing circuit such as color separation, and then recorded on a magnetic disk as an image signal. ing.

Incidentally, the photoelectric conversion element, gate electrode section, transfer section, etc. of a CCD are composed of semiconductor elements. When moving charges from the accumulation section to the transfer section, the voltage applied to the electrode section is controlled to change the surface potential of the electrode section, thereby moving the charges from the accumulation section to the transfer section. Furthermore, when charges are accumulated in the storage section, the surface potential of the gate section prevents the charges from flowing into the transfer section.

Also, JP-A-62-290279 and JP-A-63
- As shown in Publication No. 36676, vertical transfer C from the light receiving section
There is a device that enables frame overshadowing by transferring charge once to the CD and then transferring the charge again to the light receiving section.

<Problems to be Solved by the Invention> However, in such conventional devices, since there is a gate part and an electrode part between the storage part and the transfer part, it is difficult to move the charge from the transfer part to the storage part. I couldn't do it.

In addition, in order to move the charge from the transfer section to the storage section,
It is necessary to provide an independent gate section and an electrode section between the storage section and the transfer section, which increases the cost and increases the size of the CCD, which is disadvantageous in manufacturing the CCD.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for driving a charge-coupled device that can mutually transfer charges between an accumulation section and a transfer section without providing an independent gate. shall be.

Means and Effects for Solving the Problems> For this reason, the present invention provides a plurality of photoelectric conversion elements arranged in a 7-trix pattern, and a storage section that accumulates charges photoelectrically converted by each photoelectric conversion element. , a transfer device that is disposed between adjacent storage portions in a predetermined direction, changes the surface potential according to the voltage applied to the electrode, and transfers the charge accumulated in the storage portion to another direction orthogonal to the predetermined direction. a gate section disposed between the transfer section and the storage section to change the surface potential in accordance with the voltage applied to the electrode and transfer charges from the storage section to the transfer section; The transfer section is a method for driving a charge-coupled device, comprising: a separation section disposed between adjacent accumulation sections in the predetermined direction and having a substantially constant surface potential; The applied voltage is variably controlled to four different voltage values, two of the voltages are used to transfer the charge in the other direction, another value is used to transfer the charge from the storage section to the transfer section, and the remaining voltage is When the value is 1, the charge is moved from the transfer section to the adjacent storage section by overcoming the separation section.

<Example> An example of the present invention will be described below based on FIGS. 1 to 5.

In FIG. 1, a large number of photoelectric conversion elements 1 consisting of light-receiving diodes and the like are arranged in a matrix. Between these photoelectric conversion elements l, there is a vertical transfer CC as a transfer part that vertically transfers the charge in the storage part 1a of each photoelectric conversion element l.
A number of electrodes corresponding to the respective photoelectric conversion elements 1 are arranged in the vertical direction on this vertical transfer CCD 2 at predetermined intervals. The corresponding number is usually two electrodes for one photoelectric conversion element. The photoelectric conversion element 1 and the corresponding vertical transfer CCD 2 are connected by a gate section 3 made of a semiconductor or the like, and electrodes for changing the surface potential of the gate section 3 are attached to these gate sections 3. Further, the vertical transfer CCD 2 and the storage section 1a of the adjacent photoelectric conversion element 1 are connected by a separation section 4 made of a semiconductor or the like, and a predetermined voltage is applied to these separation sections 4 so that they have a substantially constant surface potential. .

Further, a horizontal transfer CCD 5 is provided which transfers charges from the vertical transfer CCD 2 in the horizontal direction.
The final stage of is connected to the input terminal of an output amplifier 7 via a changeover switch 6.

The output signal of the output amplifier 7 is the first one as shown in FIG.
and a second sample-and-hold circuit 8.9, respectively. The first sample and hold circuit 8 performs color signal processing based on the output signal of the first amplifier 7, and inputs a green signal to the matrix circuit IO at a predetermined timing. Further, the second sample and hold circuit 9 performs color signal processing based on the output signal of the first amplifier 7 and outputs a red signal or a blue signal to the matrix circuit 10 .

Further, the second sample hold circuit 9 inputs a blue signal or a red signal to the matrix circuit 10 via the IH delay circuit 11.

The first and second sample and hold circuits 8 and 9 include a first
Actuation signals are input from the and second AND circuits 12 and 13, respectively. A clock pulse signal CLK is input to one terminal of each of the first and second AND circuits 12 and 13.

Further, the operation switching pulse signal TP is input to the other terminal of the first AND circuit 12 via the changeover switch 14, and the second
An operation switching pulse signal TP is input to the other terminal of the ND circuit 12 via a changeover switch 14 and a first inverter 15. Further, a second inverter 16 is provided at one input terminal of the changeover switch 14, and by the selection operation of the changeover switch 14, the operation switching pulse signal TP is directly or inverted by the second inverter 16, and the operation changeover pulse signal TP is inverted directly or by the second inverter 16. The signal is input to the first AND circuit 15.

Here, vertical transfer CCD2. The voltage of the electrode of the gate section 3 is switched in multiple stages, and the surface potential energy thereof changes as shown in FIG.

Next, the operation will be explained with reference to FIG.

When performing the CCD driving method according to the present invention, the final stage two of the horizontal transfer CCD 5 is operated by operating the changeover switch 6.
The charges transferred from the front stage are manually supplied to the output amplifier 7.

Also, by operating the changeover switch 14, the second inverter 1
The operation switching pulse signal TP inverted in step 6 is subjected to the first AND
It is output to the circuit 12 and the first inverter 15.

Then, as shown in the second drawing, the electrode voltage of the vertical transfer CCD 2 is changed. At the same time, the electrode voltage of the gate section 3 is set to M higher than the above-mentioned L0. In this way, the surface potentials of the storage section 1a and the vertical transfer CCD 2 of the photoelectric conversion element 1 are both lowered, and the surface potential of the gate section 3 is higher than them, and the vertical transfer CCD 2 is transferred from the storage section 1a.
Charge transfer to D2 is stopped.

In this state, when light is introduced into the photoelectric conversion element 1, photoelectrically converted charges (pixels) are stored in the storage section 1a.

During this charge accumulation, the vertical transfer CCD 2 is driven at high speed to discard excess charges.

When the accumulation is completed, the electrode voltage of the vertical transfer CCD 2 is applied to all pixels as shown in FIG. At the same time, the electrode voltage of the gate section 3 is set to the above-mentioned L0. As a result, as shown in FIG. 2, the surface potential of the gate section 3 becomes similar to that of the storage section 1a, and the surface potential of the vertical transfer CCD 2 becomes lower than that of the gate section 3.

Then, as shown in FIG. 2, the charges accumulated in the accumulation section 1a are transferred to the vertical transfer CCD 2 corresponding to the accumulation section 1a.

Immediately after the movement, as shown in FIG. 2, the electrode voltage of the gate section 3 is returned to M, and the vertical transfer CCD 2
The electrode voltage of to be restored.

At this time, the photoelectric conversion element 1 is shielded from light and an overflow control gate (not shown) is controlled to discard the unnecessary charges accumulated in the storage section 1a until the light is shielded, and then the state is shifted to the state shown in FIG. 2 0. .

That is, the electrode voltage of the vertical transfer CCD 2 is set to 14 degrees, similar to the electrode voltage of the separation section 4, and the electrode voltage of the gate section 3 is set to H, which is higher than the aforementioned 1 degree. As a result, as shown in FIG. 2, the surface potential of the vertical transfer CCD 2 becomes similar to that of the separation section 4, and the surface potential of the gate section 3 becomes higher than that of the vertical transfer CCD 2.

Therefore, the charges in the vertical transfer CCD 2 are transferred to the adjacent storage section 1a over the separation section 4.

Then, as shown in FIG. 2 (■), the electrode voltages of the vertical transfer CCD 2 and gate section 3 are returned to the state shown in FIG. 2, and voltage control of Q to 0 in FIG. The charge in the storage section 1a is transferred to the corresponding vertical transfer CCD 2.

Then, in the vertical transfer CCD 2, the adjacent vertical transfer CCD 2 is alternately put into the state shown in FIG. 2 0 and the state shown in FIG.
Transfer to D5.

At this time, charges (pixels) are transferred from the vertical transfer CCD 2 one line adjacent (on the right side in FIG. 1) to the horizontal transfer CCD 5 than usual.
Therefore, charges are input to the output amplifier 7 from two stages before the final stage of the horizontal transfer CCD 5, and the shift is corrected.

Incidentally, the deviation may not be corrected at this time, but may be corrected in the color separation circuit or COD.

Here, when a color filter having the configuration shown in Fig. 4 is attached to the CCD, since every other line is read out in an interlaced manner, the CCD output is a red (R) signal or a green (G) signal and a green signal or green signal for every other line. Blue C
B) becomes a signal.

For this reason, as shown in FIG. 5, the operation switching pulse signal T whose voltage changes for each line and the clock pulse signal CL
K and the first and second sample and hold circuits 8.
9 alternately output color signals to the matrix circuit IO. The signal output from the matrix circuit 10 is then recorded as an image signal on a magnetic disk (not shown) via a signal processing circuit (not shown). Next, the voltage control shown in FIGS. 2A to 2C is performed on the pixels in the other field, and the same control is performed thereafter.

In this way, image signals of two fields (one frame) exposed simultaneously are read out and recorded on the magnetic disk. In the above explanation, a certain relationship is maintained that the potential of the gate section 3 is higher than that of the vertical transfer CCD 2. Therefore, by machining during the CCD manufacturing process, if a structure is created in which the potential of the gate part 3 becomes higher even when the same voltage is applied, the electrodes of the CCD 2 and the gate part 3 can be made common and the structure can be simplified. can.

As explained above, since the voltage applied to the electrodes of the vertical transfer CCD 2 is variably controlled to four voltage values of H, , H, , L, and Ll, two of the voltages applied to the vertical transfer CCD 2 are With the value (L,, M), charges can be vertically transferred in the vertical transfer CCD 2, and with other l values (L,), the charge can be transferred vertically in the storage section 1.
Charges can be transferred from a to the vertical transfer CCD 2, and the remaining 1 value (H3) can be transferred from the vertical transfer CCD 2 to the adjacent storage section 1a. Therefore, charges can be transferred from the vertical transfer CCD 2 to the storage section 1a without providing an independent gate section, etc., so that it is possible to suppress an increase in the cost of the CCD and an increase in size, which is advantageous in manufacturing the CCD.

<Effects of the Invention> As explained above, the present invention variably controls the voltage applied to the electrodes of the transfer section to four different voltage levels, so that the storage section and the transfer section can be connected without providing an independent gate or the like. This is advantageous in manufacturing the CCD because the charge can be transferred between the parts.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a CCD showing an embodiment of the present invention;
The figure is a diagram for explaining the action of the above, Figure 3 is a circuit diagram of other essential parts of the same as the above, Figure 4 is a diagram showing an example of a CCD color filter, and Figure 5 is a time chart of Figure 4. be. l...Photoelectric conversion element 1a...Storage section 2...
・Vertical transfer CCD 3...Gate section 4...
Separation part Figure 1 CL "L 几" soil "L 珪" bottom

Claims (1)

[Claims] A plurality of photoelectric conversion elements arranged in a matrix,
An accumulation section that accumulates the charge photoelectrically converted by each photoelectric conversion element, and an accumulation section that is arranged between adjacent accumulation sections in a predetermined direction and changes the surface potential according to the voltage applied to the electrode. a transfer section that transfers the accumulated charge in another direction orthogonal to the predetermined direction; and a transfer section that is disposed between the transfer section and the accumulation section and changes the surface potential according to the voltage applied to the electrode to accumulate the charge. a gate section for transferring charges from the transfer section to the transfer section; and a separation section disposed between the transfer section and an accumulation section adjacent to the transfer section in the predetermined direction and having a substantially constant surface potential. A method for driving a charge-coupled device comprising: variably controlling the voltage applied to the electrode of the transfer section to four different voltage values;
A value transfers the charge in the other direction, another value moves the charge from the storage section to the transfer section, and the remaining one value moves the charge from the transfer section to the adjacent storage section over the separation section. 1. A method for driving a charge-coupled device, characterized in that: