JP2003143614A - Drive method for solid-state imaging element and image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the quality of a moving picture of an object at photographing, the pixels of which are interleaved by means of a single color CCD in common use for a still picture/moving picture and used for a digital camera. SOLUTION: All electric charges of red signals are first read to a vertical transfer line in two-color filter pixels on one longitudinal column along each vertical transfer line. Then while an electric charge read voltage is applied to an electric charge read electrode of a particular system in a plurality of systems of electric charge read electrodes, the electric charges are vertically transferred to sum the electric charges of pixels of the same color on the vertical transfer line. Further, electric charges of green signals are read to the vertical transfer line so as not to be mixed with the electric charges of the red signals, the vertical transfer and the selective electric charge reading are combined to sum the electric charges of the same color in the pixels on the vertical or horizontal transfer line. The frame rate can be enhanced in a simple configuration and the image quality of the moving picture can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a solid-state image pickup device used in an image pickup apparatus such as a digital camera and a movie camera, and an image pickup apparatus.

[0002]

2. Description of the Related Art Recently, in image pickup apparatuses such as so-called electronic still cameras and movie cameras, a still image / moving image pickup element is often used instead of a conventional moving image pickup element. Such a still image / moving image pickup device is a so-called multi-pixel image pickup device in which the number of pixels is set to be significantly larger than that of a conventional moving image-dedicated image pickup device for the purpose of capturing a still image with extremely high resolution. It is used.

Therefore, when a still image is picked up by such a multi-pixel image pickup device, compared with a conventional still image picked up by a moving image pickup device, it is very precise and of high quality, for example, A.
It is possible to obtain a high-quality image that can be fully appreciated even when printed in 4 sizes. On the other hand, if an attempt is made to shoot a moving image as it is with such a multi-pixel image pickup device, the number of pixels is too large, so the time required to read the image for one frame constituting the moving image becomes long, and a smooth moving image can be obtained. It gets harder. In this respect, a configuration is conceivable in which the operating speed of the image pickup device itself and the operating speed of the peripheral circuits of the image pickup device are increased to cope with this, but such an increase in speed causes a significant increase in cost and is not realistic.

Therefore, in the case of using a multi-pixel image pickup device, the pixel signals of all pixels are usually read individually when a still image is taken, but the signal of some pixels is thinned out and read when a moving image is taken. Has been done. Then, as a solid-state imaging device, a multi-pixel CCD (charge coupled device, charge
In the case of using a so-called CCD which is an imaging device, that is, a CCD image sensor, as a thinning method, a vertical method, that is, a method of thinning horizontal lines at a specific ratio is generally adopted at present. Has been done.

Here, in the CCD, photodiodes forming pixels are arranged in a two-dimensional lattice to form an image pickup surface, and an image formed by an optical system on the image pickup surface is converted into light for each pixel. This is an image pickup device of a type in which the magnitude of the amount of charge accumulated in each photodiode is extracted as a signal in accordance with the strength of. Then, the signal charge is CC for each pixel in order.
After being sent to the output circuit in D, the charge signal amount is converted into a voltage change signal by one charge-voltage converter, and then C
It is output to the outside of the CD. The operation of guiding the signal charge of each pixel to the output circuit in this manner is called transfer. A method that is generally performed as a method of sequentially transferring the signal charges of the pixels arranged in a two-dimensional rectangular shape to the output circuit is a method that combines so-called vertical transfer and horizontal transfer. Here, when the vertical direction of the imaging screen is vertical and the horizontal direction is horizontal, the vertical transfer is an operation of transferring the signal charges of all pixels all at once in the vertical direction and in the above-mentioned output circuit direction. The transfer means that the signal charge for one horizontal line, which was sent to the horizontal transfer path by the above-mentioned vertical transfer for one stage and was located at the end in the vertical direction, that is, the part closest to the output circuit, was transferred in the horizontal direction. This is an operation of simultaneously transferring to the output circuits of. At this time,
The signal charge for one pixel located at the end of the horizontal transfer path, that is, the portion closest to the output circuit is sent to the charge-voltage converter. In this way, by repeating horizontal transfer, all the signal charges in the horizontal transfer path are converted into charge-voltage, and when the output ends and the horizontal transfer path becomes empty, the vertical transfer is performed again. Then, after the signal charge for one horizontal line at the next end in the vertical direction is sent to the horizontal transfer path again,
Similarly, by horizontal transfer, they are sequentially sent to the output circuit and output. In this way, when all the pixels are output by sequentially repeating the simultaneous vertical transfer of the signal charges of all the pixels and the simultaneous horizontal transfer of the signal charges on the horizontal transfer path, the output of the pixel signals for one screen is completed. As a result, the electronic image can be formed and restored.

In the operation of transferring the signal charge of each pixel, normally, the vertical transfer is the normal transfer in which the signal charge is transferred in the horizontal transfer path direction, that is, in the positive direction as described above. In the vertical transfer, it is also possible to perform reverse transfer (vertical reverse transfer) in the opposite direction to the horizontal transfer path. However, in recent years, due to the tendency of pixels to become significantly finer and the power consumption to be reduced with the increase in the number of pixels, the transfer drive voltage has been lowered, and vertical transfer can be performed easily and efficiently as in the past. Has become difficult. Then, with such a point as the background, the CC of multiple pixels
In D, a design in which the efficiency of vertical transfer in the forward direction is pursued is made, and as a result, a CCD in which the transfer efficiency of reverse transfer is significantly reduced is also used.

Of the various types of CCDs, the one commonly used as the above-mentioned multi-pixel CCD is a CCD called an interline type, and this interline type CCD is further interlaced by a scanning type. Scan type CCD (hereinafter interlaced CC
D) and a progressive scan CCD (hereinafter referred to as progressive CCD). The interlaced CCD currently has the best balance between cost and performance, and is widely used and adopted as a structure suitable for a multi-pixel image pickup device. In this interlaced CCD, the number of horizontal lines of charges (also called pixel signal charges, signal charges, and pixel charges) that can be held in the vertical transfer path is half the number of horizontal lines of the photodiodes that are photoelectric conversion units and constitute one pixel. Therefore, in order to read all the pixels independently, one frame is divided into two fields, and the even lines and the odd lines are alternately read, that is, interlaced and read twice. Therefore, as a charge read electrode (also referred to as a signal charge read electrode or a charge read gate electrode) to the vertical transfer path of charges on the photodiode, two systems are prepared for even lines and odd lines. And
In the interlaced CCD, for example, by increasing the number of charge reading electrodes from two to four, only some lines are selectively read out, and all combinations of color filters are read out to the vertical transfer path in one field, and the rest. It is possible to provide a configuration in which the line reading has selectivity such as not reading, and the line thinning function is easily realized. In addition, the vertical transfer of such a multi-pixel interlaced CCD is generally performed by four-phase driving, and in order to realize the line thinning function, for example, four systems of charge read electrodes are included in electrodes of a vertical transfer path. The number of conventional 4 systems becomes 6 systems.

On the other hand, in contrast to such an interlaced CCD, the progressive CCD can hold electric charges in the vertical transfer path by the number of lines of the photodiode,
All lines of one frame can be read in order from the beginning. Therefore, if the thinning-out is not performed, the charge read-out electrode can be configured by one system, but in order to realize the read-out line selectivity in order to perform the thinning-out reading, one more system of the charge read-out electrode is added. . Therefore, the vertical transfer of the progressive CCD requires a total of 2 charge read electrodes.
When the system is included, the number of electrodes of the vertical transfer path becomes 5 in the case of 4-phase drive, and the system becomes 3 in the case of 3-phase drive.

Although the charge read electrode structure is made multi-system like this, there is a disadvantage in that the internal wiring of the CCD is complicated and the external CCD drive circuit is increased by an increase in the electrode structure as compared with the conventional one. It is used in most multi-pixel CCDs, as there may be no lower cost alternative.

In addition to the general line-thinning readout as described above, various horizontal line-thinning and line-adding readout methods are available for progressive CCDs, as disclosed in Japanese Patent Laid-Open No. 10-136244. Proposed. These methods are roughly classified into (1) a method of reading only n lines out of m lines (m>
n, m ≧ 3), (2) a method of adding and reading charges of n lines among m lines (m> n), and (3) a method of adding and outputting pixel signals of q lines continuous in the vertical direction. Three schemes are shown. Then, in contrast to a configuration in which unnecessary lines are simply thinned out, a configuration in which charges are added between a plurality of lines and a frame rate is improved is shown.

That is, although the frame rate can be improved by the method of selectively reading out only a specific line and thinning out the rest as in the above-mentioned conventional technique, it is important for reproducing the spatial frequency in the vertical direction of the photographed image. May cause problems. That is, in the state where the lines are thinned out, the MTF of the photographing lens is reduced although the spatial sampling frequency in the vertical direction and the aperture ratio are correspondingly reduced.
Since the (modulation transfer function) remains unchanged, significant aliasing distortion occurs. This phenomenon is called moiré, and is a phenomenon in which, for example, an object having a fine striped pattern appears in a thick striped pattern different from the actual image, which is not desirable for an image pickup apparatus.

To alleviate this phenomenon, it is possible to introduce line addition as shown in Japanese Patent Laid-Open No. 10-136244, instead of simply thinning out lines for the purpose of improving the frame rate. . Then, even if the MTF of the photographing lens is high on the spatial sampling frequency after line thinning, the aperture ratio increases when line addition is performed, and the spatial frequency components in the high frequency band are reduced, and the same effect as the spatial filtering process can be obtained. To be In order to maximize this effect, for example, in order to increase the frame rate by 5 times, it is not necessary to thin out 4/5 lines out of all lines and read out 1/5 lines. By adding and reading with the same color of,
Eventually, all pixels are read out at a frame rate of 5 times, the effect of the spatial filter is maximum, and the pixel charge of all pixels contributes to image pickup, so that the aperture ratio is exactly the same as that at the time of still image shooting.

However, Japanese Patent Laid-Open No. 10-136244
The publication does not propose a method for reading out all pixel charges by adding a plurality of lines of the same color as described above. Although a method of reading out all pixels by adding charges on consecutive lines on a vertical transfer path or on a horizontal transfer path is mentioned, this method is not applicable to color CCDs other than the vertical stripe filter array. ,
There is a problem that color mixing occurs, which not only causes a serious adverse effect on color reproducibility but also cannot reproduce the original color depending on the combination of color mixing. Here, the above-mentioned JP-A-10-13
Although not shown in Japanese Patent No. 6244, if all pixels are read out by the addition of a plurality of lines of the same color with the configuration described in this publication, for example, in the case of the above-mentioned 5-line addition, Assuming that the color filter array is a Bayer array, there are two types of color combinations in a vertical column, each color is individually, and further, each color has five combinations.
Since it is necessary to read out pixels individually, a total of 10 charge read electrodes are required. In the case of vertical transfer drive,
The calculation requires a total of 12 systems as the vertical transfer electrodes. The existing three-phase vertical transfer and thinning-out compatible three-phase multi-pixel progressive CCD vertical transfer electrodes have four systems as described above. Therefore, eight systems of external vertical transfer drive circuits are added. Therefore, the scale of the CCD drive circuit will be significantly increased. Further, as the number of CCD pixels increases and the number of addition lines increases, the number of vertical transfer electrode systems increases correspondingly. Further, such an increase in the number of vertical transfer electrode systems is not preferable in terms of cost, downsizing of the apparatus, power consumption, and the like.

[0014]

As described above, when a multi-pixel image pickup device is used for a moving image-dedicated image pickup device in order to improve the quality of a still image, the frame rate is improved. In this case, the pixel signal is thinned out at the time of shooting, but in this case, the method of simply reading out only a specific line and thinning out the rest reduces the image quality of the moving image, while the conventional structure reduces all pixels. If the charges are added to be used for use, the configuration becomes complicated and there is a problem that the cost is increased.

The present invention has been made in view of the above point, and can realize high image quality while improving the frame rate by adding charges of pixels of the same color, and can reduce cost with a simple structure. An object of the present invention is to provide an element driving method and an imaging device.

[0016]

According to a first aspect of the present invention, there is provided a method for driving a solid-state image pickup device, comprising a plurality of pixels, each of which has a photoelectric conversion means and in which a first color and a second color are arranged in a predetermined pattern. A method of driving a solid-state imaging device, comprising: a plurality of first transfer paths for reading and transferring charges of pixels; and a second transfer path for reading, transferring, and outputting charges transferred by the first transfer paths. The charge of the pixels of the first color to the first
A plurality of charges are read to the transfer path of, the charges of other pixels that have been read are transferred while maintaining the state of reading the charges of a specific pixel, and the charges that have been read are added, and the transferred charges are added to the held charges. A first adding step of generating a first added charge by adding a plurality of charges of pixels of the first color; and removing the first added pixel from a position where the charges of the pixels of the second color are read out. In this state, a plurality of charges of the pixels of the second color are read out to the first transfer path, and a plurality of charges of the pixels of the second color are read at least in the first transfer path and the second transfer path. On the other hand, a second addition step of adding the charges of the pixels of the second color to generate a second addition charge, and the first addition charge and the second addition charge are added to the second addition step. And an addition output step of transferring and outputting the transfer path.

In this configuration, among the plurality of pixels arranged in a predetermined pattern, the charges of the plurality of pixels of the first color are first read out to the first transfer path, and the charges of the particular pixel are read out. While holding the charges, the read charges of the other pixels are transferred, and the transferred charges are added to the held charges to generate a first added charge by adding a plurality of charges of the pixels of the first color. Next, transfer and selective charge reading are combined so as not to add to the first added charge, and a plurality of charges of the pixel of the second color are read to the first transfer path, and the charge of the pixel of the first color is read. Similar to the charge, the charges are added in the first transfer path, or read from the first transfer path to the same position in the second transfer path and added to generate the second added charge. And
By transferring and outputting the first and second added charges through the second transfer path, the pixels are thinned out and the frame rate is improved as compared with the state where all the pixels are sequentially read and output. Furthermore, since pixels can be thinned out by reading out all pixels and adding a plurality of charges of pixels of the same color, the image quality is improved as compared with a configuration in which pixels are selectively read out.

According to a second aspect of the present invention, there is provided a method for driving a solid-state image sensor, comprising:
The first addition step and the second addition step are performed while transferring the charges read to the first transfer path in the forward direction and the reverse direction.

With this configuration, the first added charge and the second added charge can be output in a desired order, and the processing in the subsequent process becomes easy.

According to a third aspect of the present invention, there is provided a method of driving a solid-state image pickup device, comprising:
The second addition step is performed by reading out a plurality of charges of the pixel of the second color at a predetermined position of the second transfer path.

Further, in this structure, the reading and adding operation of charges to the first transfer path is performed in a relatively short time.

A solid-state image pickup device driving method according to a fourth aspect is the solid-state image pickup device driving method according to any one of the first to third aspects, in which the first transfer path has a charge reading electrode for each pixel. A coupling element is provided, and charge reading and holding are performed by applying a charge reading voltage to the charge reading electrode.

In this configuration, in the first adding step, the charge reading voltage is applied to the plurality of charge reading electrodes to read the charges of the plurality of pixels to the first transfer path, and then the specific charge reading electrodes are read. This is performed by performing transfer through the first transfer path while applying the charge read voltage to the.

According to a fifth aspect of the present invention, there is provided a method of driving a solid-state image pickup device according to any one of the first to fourth aspects, wherein the first addition step, the second addition charge, and the addition output step are performed. The first drive mode to be performed, and the charge of each pixel is individually read to the first transfer path, the read charge is individually transferred to the second transfer path, and the second charge is output from the second transfer path. The drive mode can be switched.

In this configuration, the state in which a high-definition image is output by using all pixels and the mode in which pixels are thinned out and output at high speed is easily switched and used.

According to a sixth aspect of the present invention, there is provided a method of driving a solid-state image pickup device according to the fifth aspect, wherein
The first driving mode is a moving image mode for shooting a moving image, and the second driving mode is a still image mode for shooting a still image.

With this configuration, a high-definition still image signal can be output, and a high-speed frame rate real-time moving image signal with improved image quality can be output. A configuration suitable for an imaging device that switches between and to capture images is realized.

An image pickup device according to a seventh aspect comprises a solid-state image pickup element and a drive circuit for driving the fixed image pickup element.
The solid-state imaging device includes a plurality of pixels that are provided with photoelectric conversion means and in which a first color and a second color are arranged in a predetermined pattern, and the drive circuit includes a plurality of pixels that read out and transfer charges of the pixels. The driving circuit includes a first transfer path and a second transfer path that reads out, transfers, and outputs the charge transferred by the first transfer path, and the drive circuit transfers the charge of the pixel of the first color to the first transfer path. A plurality of read charges are transferred to one transfer path, and the read charges of other pixels are transferred while maintaining the read charge state of a specific pixel and the read charges are added to the held charge. , The first added charge is generated by adding a plurality of charges of the first color pixel, and the first added pixel is removed from the position where the charge of the second color pixel is read out. The charge of the pixel of the second color is the first
A plurality of charges on the pixels of the second color, and a plurality of charges of the pixels of the second color are added to at least one of the first transfer path and the second transfer path to obtain a plurality of charges of the pixels of the second color. The second added charge that is added is generated, and the first added charge and the second added charge are transferred through the second transfer path and output.

In this configuration, among the plurality of pixels arranged in the predetermined pattern, the charges of the plurality of pixels of the first color are first read out to the first transfer path, and the charges of the particular pixel are read out. While holding the charges, the read charges of the other pixels are transferred, and the transferred charges are added to the held charges to generate a first added charge by adding a plurality of charges of the pixels of the first color. Next, a plurality of charges of the pixels of the second color are read out to the first transfer path so as not to be added to the first added charges, and the charges of the pixels of the first color are read in the same manner as the charges of the first transfer path. , Or read from the first transfer path to the same position on the second transfer path and add to generate a second added charge. Then, by transferring and outputting the first and second added charges through the second transfer path, pixels are thinned out and the frame rate is improved as compared with a state in which all pixels are sequentially read and output. Further, since pixels can be thinned out by reading out all pixels and adding a plurality of charges of pixels of the same color, the image quality can be easily improved as compared with a configuration in which pixels are selectively read out.

An image pickup device according to an eighth aspect is the image pickup device according to the seventh aspect, wherein the first image output from the solid-state image pickup element is used.
The processing means is capable of changing the order of the additional charge and the second additional charge.

Further, in this configuration, since the processing means for changing the order of the output signals is provided, the first added charge and the second added charge which are added and output on the first transfer path and the second transfer path. It is not always necessary to arrange the order of the added charges. Therefore, in each transfer path, charges need only be transferred in one direction, and need not be transferred in the opposite direction. Therefore, CCDs with poor transfer efficiency in the reverse direction can also be supported, and versatility is improved. improves.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for driving a solid-state image pickup device and an image pickup apparatus according to the present invention will be described below with reference to the drawings.

First of all, the present invention will be outlined.
CCD image sensor using vice), so-called CCD
And is used for image pickup devices such as digital cameras and movie cameras. In particular, the CCD of the present invention is
It is used for an image pickup device that can be used not only for still image shooting but also for moving image shooting. Is.

In this CCD, one of the two color filter pixels of two colors arranged in a column along each vertical transfer path as the first transfer path is first charged in the same color (pixel signal charge, signal). Charge, also called pixel charge) to the vertical transfer path,
By performing vertical transfer while applying the charge read voltage to the charge read electrodes of a specific system, line addition of the same color is performed on this vertical transfer path. Further, by combining the vertical transfer and the selective reading by a plurality of charge read electrodes, the charge read earlier and added on the vertical transfer path and the charge of the other line of another color read later are combined. By avoiding the color mixture of the other, the pixels of the line including the other color filter pixel are read out to the vertical transfer path, and the vertical transfer is performed while the charge read voltage is applied to the specific charge read electrode as in the first color. Alternatively, by combining the line addition operation on the horizontal transfer path as the second transfer path, the line addition of the same color read out later is performed, and as a result, the same color is added by a plurality of lines to obtain the total. Pixel readout can be performed to improve the frame rate, while achieving significant improvement in the image quality of moving images such as improved vertical spatial frequency reproducibility and pixel sensitivity. Together can also be applied to D, it is those which can suppress an increase in manufacturing cost while suppressing complication of the structure.

That is, in a multi-pixel CCD, pixel charges are mixed by performing vertical transfer while a voltage is being applied to a specific read electrode after reading charges to a vertical transfer path, and a high-speed high-quality moving image can be obtained. Furthermore, the quality of moving images can be improved only by the reading method.

As will be described in detail below, in the first embodiment, an interlaced CCD transfers vertical transfer only in the positive direction (normal transfer) and performs addition in the horizontal transfer path. . In the second embodiment, the interlaced CCD transfers vertical transfer in the reverse direction as well as the forward transfer (reverse transfer). Also,
The third embodiment uses a progressive CCD to perform not only forward transfer but also reverse transfer for vertical transfer. In the fourth embodiment, a progressive CCD is used to perform vertical transfer only for normal transfer and to perform addition on the horizontal transfer path. In addition, the fifth embodiment,
The interlaced complementary color line sequential CCD transfers vertical transfer in reverse as well as forward transfer. In the sixth embodiment, an interlaced complementary color line sequential CCD is used to perform vertical transfer only in normal transfer and to perform addition in the horizontal transfer path.

As described above, according to the present invention, in a multi-pixel interline CCD for color single plates of any color filter array, for moving and still images, and for thinning, high-speed full-line by multiple line addition avoiding secondary color mixture Pixel readout can be performed in any number of line additions without increasing the number of vertical transfer electrodes as the number of line additions increases.
This can be realized with the same minimum vertical transfer electrode configuration.

In addition, when the pixels of the same color are added together, a reverse point transfer in the vertical transfer path may be performed to facilitate the processing after the output from the CCD.
Further, in a CCD or the like, which has a low reverse transfer efficiency, it is possible to transfer only in the forward direction.

Next, embodiments of the present invention will be described with reference to the drawings.

First, the structure using the interlaced scan type CCD (interlaced CCD) corresponding to the thinning-out, which is the first and second embodiments shown in FIGS. 1 to 19, will be outlined.

In this interlaced CCD,
Regardless of the number of lines to be added, the total number of vertical transfer electrodes including four systems of charge read electrodes does not increase to six systems. Specifically, the charge read electrodes are V1A, V1B, V3A, V3
There are four systems of B, and the vertical transfer electrodes are V1A, V1B, V2, V3A, V3.
There are 6 systems in total, B and V4. That is, it can be realized by an ordinary multi-pixel interlaced CCD.

That is, in the case of a multi-pixel interline CCD which is a color single plate having a normal color filter array, which also serves as a moving image still image, and which is thinned out, in the case of an interlaced CCD, the charge read electrodes are four types of V1A, V1B, V3A and V3B. Exists. Then, for example, in the Bayer system (primary color system) that uses R (red), G (green), and B (blue) filters, a combination of color filters in a certain column is RGRG ..., R is an even number, and G is an odd number. On the second horizontal line, the charge read electrode V1A is the charge read electrode of the G pixel of the odd line number that is a multiple of 5, and V1B is the remaining G pixel, that is, the charge read electrode of the remaining odd horizontal line, V3A. Is the charge read electrode of the R pixel having a horizontal line number that is a multiple of 10, and V3B is the charge read electrode of the remaining R pixel, that is, the remaining even-numbered horizontal line. By the way, in this case, the combination of color filters is GBGB ...
, G is on even-numbered horizontal lines, and B is on odd-numbered horizontal lines. That is, V1A serves as a charge readout electrode of a B pixel having a line number that is a multiple of 5, and V3A serves as a charge readout electrode of a G pixel that has a horizontal line number that is a multiple of 10. Hereinafter, in order to simplify the description, the same-color addition all-pixel reading operation will be described for the RGRG column. However, description will be made on the assumption that the same thing occurs in all pixels on the same horizontal line although the color combination differs for each column.

First, a charge read voltage is applied to V3A and V3B,
The charges of the R pixels as the first color, that is, the charges of the even lines are all read out to the vertical transfer path. After that, the voltage of V3B is returned to the original value, but vertical transfer is performed for four stages while the charge read voltage is applied to V3A. Then, every 10 lines (vertical transfer path 5
Since the potential well remains deep under the V3A electrodes that exist in each stage), R which is close to the upper direction of V3A at this part
The charges of the five pixels are added in the same color to generate the R five-pixel added charge (5R) as the first added charge. After that, in order to avoid color mixing, the 5 pixel added charge of R, that is, the 5 pixel added charge of the even line is vertically transferred to the lower side of the V1A electrode and temporarily saved. G pixel as the second color other than double spread, that is, 5 pixels
The charges on the odd-numbered lines other than the multiple of are read out to the vertical transfer path. Then, of these G pixels, all the electric charges at locations other than the V1A electrode where the R five-pixel added electric charge is located are read out. Then, one-stage vertical transfer is performed, this time the R five-pixel added charge is saved from the V1A electrode, and a charge read voltage is applied to V1A. As a result, under the V1A electrode, the charge of G on the V1A electrode and
The charge of G which has already been read and which has been transferred one stage above is mixed or added for a total of two pixels. Then, similarly, the vertical transfer is performed for three stages while the charge read voltage is applied to V1A. Then, since the potential well remains deep under the V1A electrodes that exist every 10 lines (every 5 vertical transfer paths), the remaining 3 G pixels adjacent to V1A in the upward direction are added at this portion, and the same color is added. 5 pixels of each other are added together, and the 5 pixel addition charge of G as the second addition charge is obtained.
(5G) is generated.

As a result, 5G, 5R,
A state in which all pixels are read is created by repeating sky, sky, sky, 5G, 5R, sky, sky, sky .... After that, when signals are read out by repeating vertical transfer 1 stage, horizontal transfer, vertical transfer 5 stages, and horizontal transfer, the same color addition all-pixels read is realized at a frame rate of 5 times.

Next, a first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an image pickup device, and this image pickup device 1 is used in a digital camera that also serves as a still image and a moving image. A CCD drive circuit 3 as a drive circuit is provided. The CCD 2 is a so-called color Bayer array thinning-compatible interline type interlaced scan CCD, which is also used as a still image / moving image, and has a significantly larger number of pixels than a CCD dedicated to moving images. By using together, while reading out all pixels individually,
When shooting a movie, only 1/5 of all horizontal lines can be selectively thinned out and read out. Even with multiple pixels, the frame rate (number of frames per unit time) during movie is kept high. It has been devised to do so.

The CCD 2 is driven by the drive signal 4 of the CCD drive circuit 3 and outputs the image signal 5. The drive signal 4 given to the CCD 2 by the CCD drive circuit 3 includes vertical transfer path gate electrodes V1A, V1B, V2, V3A, V3B, V4 through which vertical transfer path gate signals flow, as described later. Further, a driving mode switching signal 6 is input to the CCD driving circuit 3 from the control means of the digital camera, and the driving mode switching signal 6 causes the CCD driving circuit 3 to CC.
The drive operation mode of D2 is switched.
That is, in the present embodiment, the moving image mode as the first drive mode and the still image mode as the second drive mode are switched.

The CCD 2 has a photodiode 11 as photoelectric conversion means, as shown in FIG.
A vertical transfer path 12 as a first transfer path connected to the photodiodes 11 and a vertical transfer path gate signal wiring 13 connected to each of the vertical transfer paths 12 are provided. Further, in the figure, an arrow 14 indicates a forward direction which is a transfer direction to a horizontal transfer path direction (not shown). In addition, below,
The opposite direction to the horizontal transfer path direction is referred to as the reverse direction, and the transfer in the opposite direction is referred to as the reverse transfer.

The photodiodes 11 each form a pixel and are two-dimensionally arranged in a predetermined pattern. In the present embodiment, the primary color Bayer array, that is, the Bayer system which is the primary color system, is used to display the colors in predetermined columns. The combination of filters is RGRG ..., R is on an even-numbered horizontal line and G is on an odd-numbered horizontal line, and the combination of color filters in a column adjacent to this column is GBGB ... It is on a horizontal line.

The charges accumulated in the photodiodes 11 are read out to the vertical transfer path 12 side by applying a charge read pulse which is a charge read voltage having a positive potential to the gate electrodes of the vertical transfer paths 12 adjacent to each other. Be done. And
As shown in FIG. 2, the combination of the vertical transfer path gate electrodes associated with such charge reading operation of the CCD 2 is four systems of charge reading electrodes V1A, V1B, V3A, V3B, and these four systems of electrodes are provided with the charges. In addition to the vertical transfer dedicated gate electrodes V2 and V4 which do not involve the reading operation, there are a total of six systems of vertical transfer path gate electrodes, each of which is connected to the vertical transfer path gate signal line 13. Note that such vertical transfer path gate signal wiring
13 is a multi-pixel multi-pixel CCD currently used for both still and moving images.
As the most common one. In the CCD 2 of this embodiment, as shown in FIG. 2, one V1A is provided for every 10 pixels (lines) (G and B of odd line numbers that are multiples of 5).
, V3A is connected to every 10 pixels (lines) (pixels of R and B having horizontal line numbers that are multiples of 10), so that charges are selectively applied only from the pixels adjacent to V1A and V3A. It is possible to easily realize the 1/5 thinning-out reading by reading.

Note that the CCD 2 of this embodiment is merely an example, and in reality, various thinning-outs are performed depending on how many lines the electrodes corresponding to V1A and V3A are arranged in consideration of the color filter. There is a CCD corresponding to the rate.
By the way, if the number of combinations of gate electrodes accompanied by a charge read operation is easily increased in order to realize a highly complicated read operation that cannot be easily realized by the above electrode configuration, C
Not only the internal wiring of the CD becomes complicated, but also an external drive circuit is required for the number of increased vertical transfer path gate wirings, which causes adverse effects such as cost increase, device size increase, and power consumption increase. As mentioned above.

Next, the actual signal reading operation will be described from the still image mode.

First, in all the photodiodes 11, unnecessary charges are swept to the substrate portion of the CCD by the electronic shutter operation, and charge accumulation is started all at once for exposure through an optical system (not shown). Then, when the exposure is completed after a predetermined exposure time elapses, the light path to the photodiode 11 is blocked by a light-shielding device such as a mechanical shutter (not shown), and each photodiode 11 remains in a dark state until all the charges are read out. Retained.

Next, the states of charge reading and vertical transfer will be described with reference to FIGS. 3 and 4. 3 and 4
Describes the state of charge reading and vertical transfer, that is, the vertical transfer waveform and potential in the leftmost column in FIG. 2, but in the following description, the same operation is performed in all other columns including adjacent columns. Shall occur. That is, charge reading and vertical transfer are performed in horizontal line units. Also, in these FIGS. 3 and 4, V1A
The waveforms marked with V4 to V4 indicate the voltage waveforms of the vertical transfer path gate signals, and the waveforms marked A to G in the direction orthogonal to the voltage waveforms indicate the potentials of the vertical transfer paths.
In the figure, 21 is a charge read pulse and 22 is the read charge. First, as an initial state, a charge read pulse 21 is applied to V3A and V3B from a state where each vertical transfer path gate signal and potential state are shown in FIG. 3A, as shown in FIG. 3B. Then, as shown in C of FIG. 3, all the charges on the even-numbered lines are read out to the vertical transfer path. Next, by applying a predetermined voltage to V1A to V4, as shown in D to G of FIG. 3, the read charges 22 are vertically transferred by one stage, and the charges of the lowermost line are transferred to a horizontal transfer path (not shown). .
After that, all the charges (pixel charges) of one line are read out by horizontal transfer. Next, one-stage vertical transfer and horizontal transfer are repeated to read all the charges of even-numbered lines individually and output them to the outside of the CCD 2 to complete the reading of the first field.

Then, from each vertical transfer path gate signal and potential state shown in A of FIG. 4, as shown in B of FIG. 4, a charge read pulse 21 is applied to V1A and V1B. Then, as shown in C of FIG. 4, all the charges on the odd line are read to the vertical transfer path. Then, by applying a predetermined voltage to V1A to V4, as shown in D to E of FIG.
22 is vertically transferred by 1/2 stage, and further, as shown in F to I of FIG. 4, the read charges 22 are vertically transferred by one stage, and the charges of the lowermost line are transferred to a horizontal transfer path (not shown). After that, all the charges (pixel charges) of one line are read out by horizontal transfer. Then, one-stage vertical transfer and horizontal transfer are repeated to read all the charges of the odd lines individually and output them to the outside of the CCD 2 to complete the reading of the second field.

In this way, C over two fields
The reading operation in the still image mode is completed by reading the charges on the CD 2. As schematically shown in FIG. 11, the operation in the still image mode is a mode in which all pixels are individually read out by using two fields by using together with an external light shielding means, and one frame has an even line and an odd line. In 2
Although it is not suitable for moving images because it is divided and accompanied by the operation of physical light shielding means such as a mechanical shutter, and it has a very low frame rate,
Since all the pixels of a so-called multi-pixel CCD are all independently read, an extremely high-definition image that is satisfactory as a still image can be obtained.

Next, as a comparative example, CC of the present embodiment
A 1/5 thinning mode that is normally performed using D2, that is, a mode in which 4/5 lines are thinned and 1/5 lines are read out will be described. This ⅕ thinning mode is mainly used for shooting moving images, and consideration is given to how to combine the selected color filters, and it is considered that all the color filter signals of R, G, and B are aligned in one field. Since RGB are aligned in one field by one exposure and reading, it is not necessary to perform a light blocking operation by a light blocking unit such as a mechanical shutter when reading charges. And
In this mode, since the charge read pulse is applied only to V1A and V3A, the other photodiodes 11 that are not connected to V1A and V3A, that is, pixels, are not read out. That is, for example, in FIG. 2, R0, G0, G5,
Only the photodiodes 11, that is, the pixels, on the horizontal horizontal lines such as B5, R10, G10 ... Are selectively read out.

The read operation will be described below with reference to FIG. FIG. 5 describes the state of charge reading and vertical transfer in the leftmost column in FIG. 2, but in the following description, similar operations occur in all other columns including adjacent columns. I shall. That is, charge reading and vertical transfer are performed in horizontal line units. In addition, this FIG.
, 21a is a charge read pulse applied to V3A, 21a
b is the charge read pulse applied to V1A, 22a is the charge of the selected and read RG line, and 22b is the charge of the similarly selected and read GB line.

First, as an initial state, a charge read pulse 21a is applied to V3A from the state in which each vertical transfer path gate signal and potential state are shown in FIG. 5A, as shown in FIG. 5B. Then, as shown in C of FIG.
The charges 22a of the line including the R pixel are read out to the vertical transfer path every 10 lines of R10, R20, .... Then V1A
-V4 is applied with a predetermined voltage to vertically transfer the read charges 22a by 1/2 stage as shown in D to E of FIG. 5, and further, as shown in F of FIG. Add. Then, as shown in G of FIG. 5, G5, G15, ...
Similarly to B5, B15, ..., The electric charge 22b of the line including the G pixel is read out every 10 lines to the vertical transfer path. In this state, the charges 22a and 22b are present in only two of the five charge holding portions of the vertical transfer path, and the rest are empty. Therefore,
After that, charges are sequentially transferred to the horizontal transfer path by repeating horizontal transfer, horizontal transfer, horizontal transfer completion, vertical transfer path two-stage transfer, horizontal transfer ... . As schematically shown in FIG. 12, in this motion picture mode operation, the frame rate is five times as fast as that in the still picture mode, but since the lines are thinned out significantly, it is naturally obtained by this motion picture mode. The spatial frequency reproducibility of the image in the vertical direction is significantly deteriorated.

Next, regarding the moving image mode which is the all-pixel reading mode for adding 5 lines of the same color according to the present embodiment,
This will be described with reference to FIGS. 6 and 7.

6 and 7, the charge read and vertical transfer in the leftmost column of FIG. 2 is described. In the following description, all other columns including adjacent columns are described. It is assumed that the same operation occurs in. That is, addition, charge reading, and vertical transfer are performed in horizontal line units. In addition, the voltage waveform of each vertical transfer path gate signal with V1A to V4 shown in FIG. 6 and V1 shown in FIG.
The voltage waveforms of the vertical transfer path gate signals with A to V4 are the same. On the other hand, FIG. 6 shows the first half portion and FIG. 7 shows the latter half portion of the waveforms showing the potential status of the vertical transfer paths marked with AT in the direction orthogonal to this voltage waveform.

First, as an initial state, from the state in which each vertical transfer path gate signal and the potential state are shown in FIG. 6A to V3A and V3B in FIG. Give pulses 31a, 31b,
Only the charges 33 on the even lines are all read out to the vertical transfer path.
Next, as shown in C to H of FIG. 6, the application of the charge read pulse 31b for V3B is stopped, but the charge read pulse 31a for V3A is stopped.
With the above added, vertical transfer is performed in the positive direction for four stages. Then, even if vertical transfer is performed, every 10 lines, that is, 5 lines
Since the potential well is deeper in the V3A electrode section at every other stage, the charges on the read even lines (pixel charges)
In the charge holding unit under V3A, charges of 5 pixels of the same color of R pixels are mixed, that is, added. Then, with the application of the V3A charge read pulse 31a stopped, I of FIG.
Further, as shown by I in FIG. 7, the five-pixel mixed charge 34 as the first added charge, in which the charges of five pixels are added per one stage, is held.

Then, from the state shown in I of FIG. 6 and I of FIG. 7, a predetermined voltage is applied to V1A to V4, and J to J of FIG.
As shown by L, the 5-pixel mixed charge is vertically transferred by 2.5 stages in the horizontal transfer path direction, and the 5-pixel mixed charge of the even line is temporarily saved below the V1A electrode. From this state, M
As shown in, the charge read pulse 32b is applied to V1B to read 4/5 of the charge on the odd line. Next, as shown at N in FIG. 7, after the application of the charge read pulse 32b at V1B is stopped, a predetermined voltage is applied to V1A to V4, and as shown in OR at FIG. The five-pixel mixed charge 34 and the charge of 4/5 of the odd line are vertically transferred by one stage toward the horizontal transfer path.

Then, as shown in S of FIG. 7, a charge read pulse 32a is applied to V1A to read the charges of the remaining 1/5 line of the odd line to the vertical transfer path. Then, in FIG.
As shown in FIG. 7, after the application of the charge read pulse 32a of V1A is stopped, under the electrode of V1A shown in T of FIG. 7, adjacent two pixels of the odd lines are mixed and the remaining odd lines are The electric charge for one pixel is read out and held in the electric charge holding portion. In this state, 5R, 2G, G, G,
In the repeating form of G, 5R, 2G, G, G, G, ..., the charges of all pixels are partially added to the vertical transfer path and read.

Further, the subsequent vertical transfer and horizontal transfer are performed as shown in FIGS. That is, FIG. 8A shows the state of the vertical transfer path indicated by T in FIG. Also, 41 in FIGS. 8 to 10 represents a vertical transfer path,
42 indicates a horizontal transfer path. Then, at the stage of FIG. 8 (A), as a result of the process of the above-mentioned read operation, the horizontal line 42 already has an even number of 5 pixel mixed charges (R0).
+ R2 + R4 + R6 + R8) 34 is present. Therefore, FIG.
As shown in (B), this 5 pixel mixed charge (R0 + R2 + R4 +
After reading R6 + R8) 34 by horizontal transfer, as shown in FIG. 8C, vertical transfer is performed with the horizontal transfer stopped, and addition of odd lines, that is, pixel mixing is performed on the horizontal transfer path. Further, in the state shown in FIG. 8C, the charges (G1 + G3) on the horizontal transfer path are at the end of the screen, and therefore the addition is insufficient, resulting in an incomplete mixed pixel number. Therefore, FIG.
As shown in (D), after the charges (G1 + G3) are horizontally transferred and output, as shown in FIG. 9 (E), one stage of vertical transfer is performed, and five pixels are added to form an even line. The 5 pixel mixed charge (R10 + R12 + R14 + R16 + R18) 34 is transferred to the horizontal transfer path.

Then, as shown in FIG. 9F, the five-pixel mixed charge (R10 + R12 + R14 + R16 + R18) 34 is output by horizontal transfer. Next, as shown in FIG. 10 (G), vertical transfer is performed for one stage, and charges (G5 + G7) obtained by adding two pixels of the odd line are transferred to the horizontal transfer path. Then
As shown in FIGS. 10 (H to I), vertical transfer for three stages is continuously performed before horizontal transfer is performed, and odd-numbered lines are added on the horizontal transfer path to obtain 5 pixels as the second added charge. 5 pixel mixed charge (G5 + G7 + G9 + G1) which is the addition signal charge
1 + G13) 44 is generated.

After the charges are output by horizontal transfer, the operations of one-stage vertical transfer, horizontal transfer, four-stage vertical transfer, horizontal transfer ... In this way, after all the pixels are partially added to the vertical transfer path 41 and read out, the vertical transfer path 41 is read by one stage or four.
By performing the transfer operation by repeating the steps, as a result, all pixel signals can be read at a frame rate five times as high as that of the still image.

Then, FIG. 13 schematically shows a combination of pixels finally added and read by the all-pixel reading mode for adding five lines of the same color. The original arrangement of charges is G1 to 3 → R0 to 8 → G5
13 to R10 to 18 to G15 to 23 to R20 to 28 ... As can be seen from FIG. 13, in the present embodiment,
R0 ~ 8 → G1 ~ 3 → R10 ~ 18 → G5 ~ 13 → R20 ~ 28 → G15
..... 23 ... In this order, an addition signal which is a 5 pixel mixed charge is output, and the positional relationship between the even lines and the odd lines is reversed. Then, such a phenomenon is caused by the CCD arranged in the subsequent stage of the CCD 2 shown in this embodiment, which controls the image processing and the like.
2 With an external component, for example, a line buffer as a processing device capable of recording image data for one line is provided, the line signal output earlier is temporarily held, the next line signal is passed first, The compensation can be performed by performing a process of exchanging the signals of the lines and the odd lines.

Further, when the charges (pixel charges) are mixed and read out as described above, the charge transfer capacity of the vertical transfer path or the horizontal transfer path may become a problem. That is,
The transfer capacity of each transfer path needs to be five times the saturated accumulated charge amount of the photodiode 11. As a countermeasure for this, it is conceivable to use a CCD manufactured by designing and manufacturing the charge transfer capacities of the vertical transfer path and the horizontal transfer path as a capacity commensurate with the amount of pixels to be mixed. However, when pixels are mixed, it can be easily dealt with by setting the substrate bias voltage of the CCD to a correspondingly high voltage to limit the saturated accumulated charge amount of the photodiode.

In this embodiment, the primary color Bayer array has been described as an example, but the present invention is not limited to this, and what kind of filter array is provided as long as the number of color filters of one vertical line is two or less. However, it is applicable. That is, it can be applied to almost all existing filter arrays other than the filter array shown in the fourth embodiment.

As described above, according to the present embodiment, in the interlaced CCD, in almost all color filter arrays, it is possible to change the charge reading method with the current configuration, so to speak, a high frame rate same color addition all pixels. Reading can be realized. As a result, the image quality of the moving image can be significantly improved without increasing the cost or while suppressing the cost increase, and the high-sensitivity effect of the additive reading allows the shooting conditions of the moving image to be improved especially in a dark scene. It can be greatly expanded. Further, even if the number of lines added increases with the increase in the number of pixels of the CCD, the number of vertical transfer electrodes does not change, and the increase in cost can be suppressed.

Further, in the present embodiment, in the vertical transfer path, it is sufficient to transfer the charges only in the positive direction which is the horizontal transfer path direction, and it is not necessary to perform the reverse transfer. Therefore, the transfer efficiency of the reverse transfer is significantly reduced. It can also be applied to CCDs and can improve versatility.

Next, the second embodiment will be described with reference to FIG.
It will be described with reference to FIGS. The internal configuration of the CCD 2 of the second embodiment and the basic operation including driving of the CCD 2 are exactly the same as those of the first embodiment shown in FIGS. In this embodiment, in the all-pixel read drive for adding 5 lines of the same color, the line replacement processing by the components outside the CCD 2 necessary in the first embodiment is devised by devising the driving method of the CCD 2. It can be unnecessary.

Hereinafter, the same color 5 line addition all-pixel reading mode according to the second embodiment will be described with reference to FIGS. 15 and 16. 15 and 16, the state of charge reading and vertical transfer in the leftmost column in FIG. 2 is described, but in the following description, the same applies to all other columns including adjacent columns. It is assumed that the operation is occurring. That is, addition, charge reading, and vertical transfer are performed in horizontal line units. Further, the voltage waveforms of the respective vertical transfer path gate signals denoted by V1A to V4 shown in FIG. 15 and the voltage waveforms of the respective vertical transfer path gate signals denoted by V1A to V4 shown in FIG. 16 are the same. . On the other hand, FIG. 15 shows the first half part and FIG. 16 shows the second half part of the waveforms showing the potential status of the vertical transfer paths denoted by A to S shown in the direction orthogonal to this voltage waveform.

First, as an initial state, charge transfer pulses 31a and 31b are applied to V3A and V3B, respectively, from the state shown in FIG. 15A for each vertical transfer path gate signal and potential state, as shown in FIG. 15B. Then, all the charges on the even lines are read out to the vertical transfer path. Next, from C of FIG.
As indicated by H, application of the charge read pulse 31b of V3B is stopped, but vertical transfer is performed in the positive direction for four stages while the charge read pulse 31a is added to V3A. Then, even if the vertical transfer is performed, the potential wells are deeper in the V3A electrode portion in every 10 lines, that is, in every 5 steps, so the read even-numbered line charges (pixel charges) are the charges below V3A. In the holding unit, charges of 5 pixels of the same color of R pixels are mixed, that is, added. Then, with the application of the charge read pulse 31a of V3A stopped, as shown by I in FIG. 15 and I in FIG. 16, a 5-pixel mixed charge 34 in which charges for 5 pixels are added per stage is held. It will be in the state of being.

Then, from the states shown in I of FIG. 15 and I of FIG. 16, a predetermined voltage is applied to V1A to V4, and
As shown in J to K, the five-pixel mixed charge 34 is vertically transferred by 2.5 stages in a direction opposite to the horizontal transfer path, so to speak, reverse transfer,
The 5 pixel mixed charge 34 of the even line is temporarily saved under the V1A electrode. From this state, as shown in L of FIG. 16, V1B
The charge read pulse 32b is applied to 4 /
Read 5 Then, as shown in M of FIG.
After stopping the application of V1B charge read pulse 32b, V1A to V4
16 to a predetermined voltage, as shown in N to O of FIG.
5 pixel mixed charge 34 on even lines and 4/5 on odd lines
Charges of one stage are vertically transferred in the positive direction, that is, toward the horizontal transfer path.

Then, as shown in P of FIG. 16, a charge read pulse 32a is applied to V1A, and the remaining 1/5 of the odd line is supplied.
The line charge is read out to the vertical transfer path. Then, under the electrode of V1A shown in P of FIG. 16, among the odd lines,
Adjacent two pixels are mixed, and the electric charges for one pixel are read out and held in the electric charge holding portions of the remaining odd lines. From this state, as shown in Q to R of FIG.
Each charge is vertically transferred by three stages in the positive direction while the charge read pulse 32a is applied to V1A. Then, as shown in R of FIG. 16, in the charge holding portion under the electrode of V1A, the pixel of the same color of G 5
The charges for the pixels are added to generate a 5-pixel mixed charge 44. Then, after the application of the charge read pulse 32a of V1A is stopped, as shown in S of FIG. 16, the charge of each even-numbered line and the number of odd-numbered lines are added by 5 pixels in the same color for each 5 pixel mixed charge. 34 and 44 are held.

Further, the subsequent vertical transfer and horizontal transfer are performed as shown in FIGS. That is,
FIG. 17A shows the state of the vertical transfer path indicated by S in FIG. Further, 41 in FIGS. 17 to 19 indicates a vertical transfer path, and 42 indicates a horizontal transfer path. 15 and 1
In the step shown in FIG. 6, a plurality of lines are added together in the vertical transfer path 41, but at the end, for example, the lowermost line 43 on the horizontal transfer path 42 side, all effective pixels cannot be added together. An incomplete pixel mixture situation has occurred. Therefore,
First, the incomplete mixed pixels on the line 43 are read out by vertical transfer and horizontal transfer. After this, as shown in FIG. 17B, the first effective 5-pixel mixed line is transferred to the horizontal transfer path. Since there are three stages of empty charge holding portions above the five-pixel mixed line, horizontal transfer is not performed immediately at this point, and FIGS. 17C, 18D, and 18E are used. As shown in, vertical transfer is performed for three stages. That is, when the transfer of the first valid line to the horizontal transfer path is included, four stages of vertical transfer are performed before horizontal transfer. After that, as shown in FIG. 18F, horizontal transfer is performed to read out the first effective 5-pixel mixed line, and then, as shown in FIG.
Vertical transfer is performed for the number of steps, and the next effective 5 pixel mixed line is transferred to the horizontal transfer path. Then, this time, as shown in FIG. 19 (H), since an effective line exists immediately above, horizontal transfer is immediately performed, and vertical transfer for one stage is performed as shown in FIG. 19 (I).

After that, four-stage vertical transfer, horizontal transfer,
The operation of one-stage vertical transfer, horizontal transfer, ... Is repeated to read the image signal to the outside. In this way, after all pixels have been read out on the vertical transfer path and the same colors have been added together, the vertical transfer path is repeatedly transferred in the forward direction by repeating four steps and one step, resulting in 5 All pixel signals can be read at a double frame rate.

Note that FIG. 14 schematically shows a combination of pixels finally added and read in this all-pixel reading mode for adding five lines of the same color.
As described above, in the present embodiment, by performing the reverse transfer operation that is the reverse of the vertical transfer direction in the process of charge reading, the line reading order can be corrected, and the line replacement by the external component or the like becomes possible. There is no need for treatment and it is easy to reduce costs.

In addition, in the second embodiment, the line addition operation is completed not only on the even lines but also on the odd lines on the vertical transfer path. However, like the first embodiment,
The addition operation of odd-numbered lines can be realized by combining addition on the vertical transfer path and addition on the horizontal transfer path.

Also in the first embodiment, the odd line addition operation is performed as in the second embodiment.
It can also be completed on the vertical transfer path. That is, in each of the embodiments described in the present application, the addition operation of the odd-numbered lines may be completed on the vertical transfer path, and is realized by combining the addition on the vertical transfer path and the addition on the horizontal transfer path. be able to.

Next, the structure using the progressive scan type CCD (progressive CCD) corresponding to the thinning-out, which is the third and fourth embodiments shown in FIGS. 20 to 31, will be outlined.

In this progressive CCD, in the case of a three-phase vertical transfer structure, in the case of normal thinning-out, the number of charge read electrodes is two systems of V2A and V2B, and the vertical transfer electrodes are V1, V2A, V2B,
In order to realize this configuration, the total of 4 systems of V3 are 4 systems of charge read electrodes V2A, V2B, V2C, V2D, and the vertical transfer electrodes are 6 systems of these charge read electrodes plus V1 and V3. It needs to be increased, but no matter how many lines are added, the number of lines does not increase.

Further, in the case of the four-phase vertical transfer structure, the number of charge read electrodes is two systems of V2A and V2B in the normal thinning correspondence,
The total number of vertical transfer electrodes is V1, V2A, V2B, V3, and V4, but there are 5 lines of charge read electrodes to realize this structure.
There are 4 systems of 2A, V2B, V3, and it is necessary to increase the number of vertical transfer electrodes to 7 systems in which V1, V3, V4 are added to these charge readout electrodes. The number of lines will not increase.

That is, in the case of a progressive CCD,
The charge read electrodes are provided with four systems of V2A, V2B, V2C and V2D. Then, a combination of color filters in a certain column is RGRG.
, Where R is on an even-numbered line and G is on an odd-numbered horizontal line, the charge read electrode V2A is an R pixel with a line number that is a multiple of 10, and V2B is the remaining R pixel, that is, the remaining even-numbered horizontal line. It is assumed that V2C is a charge readout electrode, V2C is a G pixel of an odd line number that is a multiple of 5, and V2D is a remaining G pixel, that is, a charge readout electrode of the remaining even-numbered horizontal lines.

First, a charge read voltage is applied to V2A and V2B,
All the pixels in R, that is, the charges in the even lines are read out to the vertical transfer path. After that, the voltage of V2B is returned to the original value, but vertical transfer is performed for eight stages while the charge read voltage is applied to V2A. Then, since the potential well remains deep under the V2A electrodes that exist every 10 lines, the signal charges of the five R pixels adjacent to the upper direction of V2A in the same color are added together in this portion, and the first added charge is added. Charge of 5 pixels of R as (5
R) is generated.

After this, the 5 pixel added charge of R, that is, the 5 pixel added charge of the even-numbered line is transferred in the opposite direction of the four-stage horizontal transfer path and saved, and then the charge read voltage is applied to V2C and V2D. In addition, all the charges of the G pixel, that is, the odd lines are read out to the vertical transfer path. As with the even lines, V2
Although the voltage of D is returned to the original value, vertical transfer is performed for 8 stages while the charge read voltage is applied to V2C. Then, the signal charges of five G pixels adjacent to the upper side of the V2C electrode in the upward direction are added together in the same color, and a G five-pixel added charge (5G) as the second added charge is generated.

As a result, 5G, 5R, sky, sky, sky, sky, sky, sky, sky, sky, 5
In the G, 5R, sky, sky ... state, a state in which all pixels are read is created. After that, if the pixel signals are read out of the CCD by repeating 1-stage vertical transfer, horizontal transfer, 9-stage vertical transfer, horizontal transfer, ... it can.

Next, FIG. 20 shows a third embodiment of the present invention.
It will be described with reference to FIGS. The configuration of the third embodiment is similar to that of the first embodiment, and the configuration diagram is the same as that of FIG. 1. However, in the present embodiment, the CCD 2 As an example, the present invention is applied to a so-called color Bayer array thinning-compatible interline type progressive scan CCD.

That is, in the third embodiment, C
The CD2 is a color Bayer array interline progressive scan CCD. This CCD 2 features both still images and moving images. Since it has a significantly larger number of pixels than CCDs used exclusively for moving images, all pixels are read out individually in order when shooting still images, but 5 pixels in a horizontal line when shooting moving images. The same colors are added and read out,
Even if the number of pixels is large, it is devised to maintain a high frame rate during moving images.

The CCD 2 is driven by the CCD drive circuit 3 and outputs the image signal 5. And C
The drive signal 4 given to the CCD 2 by the CD drive circuit 3 includes vertical transfer path gate signals V1, V2A, V2B, V2C, V2D, V3, which will be described later.
It is included. Further, the driving mode switching signal 6 is input to the CCD driving circuit 3, and the driving mode switching signal 6 is inputted.
Accordingly, the CCD drive circuit 3 switches the drive operation mode of the CCD 2.

The CCD 2 has a photodiode 11 as a photoelectric conversion means, as shown in the internal structure of FIG.
And the first CC connected to these photodiodes 11.
A vertical transfer path 12 which is D and a vertical transfer path gate signal wiring 13 connected to each of the vertical transfer paths 12 are provided. Further, in the figure, an arrow 14 indicates a positive direction which is a vertical transfer direction to a horizontal transfer path direction which is a second CCD (not shown).

Further, the photodiodes 11 respectively form pixels and are two-dimensionally arranged in a predetermined pattern. In the present embodiment, the primary color Bayer array, that is, the Bayer system which is the primary color system, is used to display the colors in predetermined columns. The combination of filters is RGRG ..., R is on an even-numbered horizontal line and G is on an odd-numbered horizontal line, and the combination of color filters in a column adjacent to this column is GBGB ..., G is an even-numbered and B is an odd-numbered. It is on a horizontal line.

The charges accumulated in the photodiodes 11 are read out to the vertical transfer path 12 side by applying a charge read pulse as a charge read voltage having a positive potential to the gate electrodes of the vertical transfer paths 12 adjacent to each other. Be done. And
As shown in FIG. 20, the combination of the gate electrodes of the vertical transfer paths accompanied by such charge reading operation of the CCD 2 is V2A, V2.
There are four systems of B, V2C, and V2D. In addition to these four systems of electrodes, gate electrodes V1 and V3 dedicated to vertical transfer without charge read operation are added, and there are six systems of vertical transfer path gate electrodes, each of which is vertical. It is connected to the transfer path gate signal wiring 13.

The CCD 2 according to the present embodiment only shows a configuration of 5-line addition as an example. In practice, electrodes corresponding to V2A and V2C are arranged on every line while considering the color filter. Therefore, it is possible to realize CCDs with various line addition numbers. In the present embodiment, no matter how the number of lines added increases, the number of vertical transfer path gate electrodes does not increase, and the cost can be suppressed.

Next, the actual signal reading operation will be described from the still picture mode.

First, in all photodiodes 11, unnecessary charges are swept to the substrate portion of the CCD by the electronic shutter operation, and charge accumulation is started all at once for exposure through the optical system. Then, when the exposure is completed after a predetermined exposure time elapses, the charges of all the photodiodes 11 are read out to the vertical transfer paths 12.

Next, referring to FIG. 21, the states of charge reading and vertical transfer will be described. FIG. 21 illustrates the state of charge reading and vertical transfer in the leftmost column in FIG. 20, but in the following description, similar operations occur in all other columns including adjacent columns. I shall. That is, charge reading and vertical transfer are performed in horizontal line units. Further, in FIG. 21, the waveforms with V1 to V3 show the voltage waveforms of the respective vertical transfer path gate signals, and the waveforms with A to I shown in the direction orthogonal to the voltage waveforms are the potentials of the vertical transfer paths. Is shown. Also,
In the figure, 51a, 51b, 51c and 51d are charge read pulses, and 52 is the read charges. First, as an initial state, each vertical transfer path gate signal and potential state are shown in FIG.
21A to V2A, V2 as shown in FIG. 21B.
Charge read pulses 51a, 51b, 51c and 51d are added to B, V2C and V2D. Then, as shown in C of FIG. 21, all the charges 52 are read out to the vertical transfer path. Next, by applying a predetermined voltage to V1A to V4, as shown in D to I of FIG. 21, the read charges 52 are vertically transferred by one stage, and the charges of the lowermost line are transferred to a horizontal transfer path (not shown). . After that, all charges of one line are read out by horizontal transfer. Next, the one-stage vertical transfer and the horizontal transfer are repeated, and the charges of the horizontal lines are sequentially read out line by line from the beginning individually and output to the outside of the CCD 2 to complete the reading in the still image mode. That is, the still image mode is a mode in which all pixels are individually read in order from the beginning in one frame, and since the number of pixels in one frame is very large, the frame rate is very slow and it is not suitable for moving images. Multi-pixel CCD
Since all of the pixels are read independently, an extremely high-definition image that is perfect as a still image can be obtained.

Next, FIG. 22 and FIG. 23 will be described with respect to the all-pixel reading mode for adding 5 lines of the same color according to the present embodiment.
Will be described with reference to.

In these FIG. 22 and FIG. 23, FIG.
The state of charge reading and vertical transfer in the leftmost column of 0s has been described, but in the following description, it is assumed that the same operation occurs in all other columns including adjacent columns. That is, addition, charge reading, and vertical transfer are
It is performed in units of horizontal lines. In addition, V1 to V3 shown in FIG.
23 and the voltage waveforms of the vertical transfer path gate signals marked with
The voltage waveforms of the respective vertical transfer path gate signals denoted by V1 to V3 are the same. On the other hand, FIG. 22 shows the first half of FIG.
Shows the latter half.

First, as an initial state, charge read pulses 51a and 51b are applied to V2A and V2B, respectively, from the state shown in FIG. 22A for each vertical transfer path gate signal and potential state, as shown in FIG. 22B. Give, even line charge
Only 52 is read to the vertical transfer path. Next, C in FIG.
As shown by K, the application of the charge read pulse 51b of V2B is stopped, but the charge read pulse 51a of V2A is kept 8
Vertical transfer is performed in the forward direction by the number of steps. Then, even if vertical transfer is performed, the potential wells become deeper in the V2A electrode portions at every 10th stage, so the charges on the read even lines are
As for (pixel charge), charges of 5 pixels of the same color of R pixels are mixed or added in the charge holding unit under V2A. Then, with the application of the V2A charge read pulse 51a stopped,
As shown in L of FIG. 22 and L of FIG. 23, the five-pixel mixed charge 54 in which the charges of five pixels are added per one stage is held.

From the state indicated by L in FIG. 23,
By applying a predetermined voltage to V1 to V3, as shown in M to R of FIG. 23, the five-pixel mixed charge 54 is vertically transferred in the opposite direction of the horizontal transfer path by four stages, that is, reversely transferred, and below the V2B electrode. The 5-pixel mixed charge 54 is temporarily saved. From this state,
As indicated by S in FIG. 5, charge read pulses 51c and 51d are applied to V2C and V2D.
And the charges on the odd lines are read out to the vertical transfer path. Next, as shown in T to X of FIG. 23, a predetermined voltage is applied to V1 to V3 in a state where the application of the V2D charge read pulse 51d is stopped while the V2C charge read pulse 51c is applied, and the vertical read is performed. Each charge 52 on the transfer path is vertically transferred in the positive direction by eight stages toward the horizontal transfer path. Then, even if vertical transfer is performed, 1
Since the potential wells are deeper in the V2C electrode section at every 0th stage, the read charges on the odd lines are V2C
In the lower charge holding portion, charges of 5 pixels of the same color of G pixel are mixed or added. Then, in a state where the application of the V2C charge read pulse 51c is stopped, as shown by Y in FIG. 23, the five-pixel mixed charge 55 in which the charges of five pixels are added per one stage is held. . Then, in the state shown in Y of FIG. 23, as shown in FIG. 24 (A), just the 5 pixel mixed charge 55 of the odd line is immediately above the 5 pixel of the even line previously read and mixed. Mixed charge 54
Exists. Therefore, as shown in FIGS. 24B and 24C, after the first five-pixel mixed charge 55 is read out and output to the horizontal transfer path, as shown in FIGS. 25D to 26I, By repeating 1-stage vertical transfer, horizontal transfer, 9-stage vertical transfer, horizontal transfer, ..., Five-pixel mixed charges 54 and 55 of the same color can be read.

In this embodiment, the primary color Bayer array has been described as an example, but the present invention is not limited to this, and what kind of filter array is provided if there are two or less sets of color filters in one vertical line. However, it is applicable. That is, it can be applied to almost all existing filter arrays other than the filter array shown in the fourth embodiment.

That is, in the progressive CCD as in this embodiment, by using four read electrodes, the same effect as above can be obtained with any color filter array. Further, in this configuration, the number of vertical transfer electrodes is increased by two systems as compared with the normal configuration, but C
Even if the number of lines added increases with the increase in the number of pixels of the CD, the number of vertical transfer electrodes does not increase any more, and an increase in cost can be suppressed.

Further, in this embodiment, after the even-line 5-pixel mixed charge is generated on the vertical transfer path, the reverse transfer is performed by the method shown in the second embodiment, that is, on the vertical transfer path. The even / odd inversion of the output line order is compensated for inside the CCD2. However, as in the fourth embodiment shown below, all of the vertical lines in the positive direction are used for the entire transfer as in the first embodiment. The line order can be compensated by a component outside the CCD that realizes pixel mixture and controls image processing. Further, also in this embodiment, similarly to the second embodiment, the pixel mixture on the odd line side can be performed on the horizontal transfer path.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described with reference to FIGS.

The basic structure including the internal structure of the CCD 2 and the driving of the CCD 2 according to the fourth embodiment is shown in FIG.
The operation is the same as that of the third embodiment shown in FIG. In this embodiment, the charges need only be transferred in the vertical transfer path only in the positive direction, which is the horizontal transfer path direction, and there is no need to transfer charges in reverse.
It can also be applied to CCDs whose transfer efficiency in reverse transfer is significantly reduced, and can improve general versatility, and by incorporating addition in the horizontal transfer path, the time required for read operation is slightly shorter than that in the third embodiment. can do.

Next, the moving image mode according to the present embodiment, that is, the all-pixel readout mode for adding five lines of the same color will be described with reference to FIGS. 27 and 28.

In these FIG. 27 and FIG. 28, FIG.
The state of charge reading and vertical transfer in the leftmost column of 0s has been described, but in the following description, it is assumed that the same operation occurs in all other columns including adjacent columns. That is, addition, charge reading, and vertical transfer are
It is performed in units of horizontal lines. In addition, V1 to V3 shown in FIG.
FIG. 28 shows the voltage waveforms of the vertical transfer path gate signals marked with
The voltage waveforms of the respective vertical transfer path gate signals denoted by V1 to V3 are the same. On the other hand, FIG. 27 shows the first half of the waveform showing the potential state of the vertical transfer path with A to U shown in the direction orthogonal to this voltage waveform, and FIG.
Shows the latter half.

First, as an initial state, charge transfer pulses 51a and 51b are applied to V2A and V2B, respectively, from the state shown in FIG. 27A for each vertical transfer path gate signal and potential state, as shown in FIG. 27B. Give, even line charge
Only 52 is read to the vertical transfer path. Next, C in FIG.
As shown by K, the application of the charge read pulse 51b of V2B is stopped, but the charge read pulse 51a of V2A is kept 8
Vertical transfer is performed in the forward direction by the number of steps. Then, even if vertical transfer is performed, the potential wells become deeper in the V2A electrode portions at every 10th stage, so the charges on the read even lines are
As for (pixel charge), charges of 5 pixels of the same color of R pixels are mixed or added in the charge holding unit under V2A. Then, with the application of the V2A charge read pulse 51a stopped,
As shown in L of FIG. 27 and L of FIG. 28, the five-pixel mixed charge 54 in which the charges of five pixels are added per one stage is held.

From the state indicated by L in FIG. 28,
By applying a predetermined voltage to V1 to V3, as shown in M to R of FIG. 28, the five-pixel mixed charge 54 is vertically transferred by six stages in the horizontal transfer path direction, that is, in the positive direction, and five pixels are mixed under the V2B electrode. Charge 54
To evacuate. From this state, as shown at S in FIG. 28, charge read pulses 51c and 51d are applied to V2C and V2D to read the charges on the odd lines to the vertical transfer paths. Then, FIG.
As shown at T in FIG. 5, these V2C and V2D charge read pulses 51
Stop application of c and 51d. In this state, as shown in U of FIG. 28, except for a part of the lowermost stage, 5R, G, G, G,
The electric charges of all the pixels are read out to the vertical transfer path in the repeating form of G, G, 5R, G, G, G, G, G, ....

Further, the subsequent vertical transfer and horizontal transfer are performed as shown in FIGS. 29 and 30. That is, FIG. 29A shows the state of the vertical transfer path indicated by U in FIG. Further, 61 in FIGS. 29 and 30 indicates a vertical transfer path, and 62 indicates a horizontal transfer path. And this FIG.
At the stage of (A), as a result of the process of the above-mentioned read operation, the horizontal transfer path 62 already has the 5 pixel mixed charges (R0 + R2 + R4 + R6 + R8) 63 of even lines. Therefore,
As shown in FIG. 29B, this 5 pixel mixed charge (R0 + R2
After reading + R4 + R6 + R8) 63 by horizontal transfer,
As shown in (C), vertical transfer is performed while horizontal transfer is stopped, and addition of odd lines, that is, pixel mixing is performed on the horizontal transfer path. Further, in the state shown in FIG. 29C, the charges (G1 + G3) on the horizontal transfer path are not added up because of the end portion of the screen, resulting in an incomplete mixed pixel number. Therefore,
After this charge (G1 + G3) is horizontally transferred and output as shown in FIG. 30 (D), one stage of vertical transfer is performed as shown in FIG. 30 (E), and an even number of 5 pixels is added. The five-pixel mixed charge (R10 + R12 + R14 + R16 + R18) 63 of the line is transferred to the horizontal transfer path.

Then, as shown in FIG.
The pixel mixed charge (R10 + R12 + R14 + R16 + R18) 63 is output by horizontal transfer. Then, as shown in FIG.
31 stages of vertical transfer is performed to transfer the electric charge (G5) to the horizontal transfer path. Then, as shown in FIG. 31H, 8 stages of vertical transfer are continuously performed before horizontal transfer is performed. , The odd-numbered lines are added on the horizontal transfer path, and the 5-pixel mixed charge (G5 +) which is the 5-pixel added signal charge as the second added charge
G7 + G9 + G11 + G13) 64 is generated.

Then, as shown in FIG. 31 (I), after this charge is output by horizontal transfer, operations such as 1-stage vertical transfer, horizontal transfer, 9-stage vertical transfer, horizontal transfer ... The image signal is read out by repeating. In this way, after all the pixels are partially added to the vertical transfer path 61 and read out, the vertical transfer path 61 is repeatedly transferred in one stage and nine stages, and as a result, 5 All pixel signals can be read at a double frame rate.

Incidentally, also in the fourth embodiment,
Similar to the first embodiment, with respect to the addition signal which is the 5-pixel mixed charge, the positional relationship between the even-numbered line and the odd-numbered line of the charge is reversed. Such a phenomenon is caused by a component outside the CCD 2 arranged in the subsequent stage of the CCD 2 according to the present embodiment, which controls image processing and the like, for example, a line buffer as a processing device capable of recording image data for one line. Is provided, the previously output line signal is temporarily held, the next line signal is allowed to pass first, and the signal of the even line and the signal of the odd line are exchanged, whereby the compensation can be performed.

Next, the structure using the interlaced complementary color line sequence, which is the fifth and sixth embodiments shown in FIGS. 32 to 38, will be outlined.

That is, the fifth shown in FIGS. 32 to 38.
And a specific color difference line sequential method (complementary color method) using filters of Ye (yellow), Mg (magenta), Cy (cyan), and G (green) as in the sixth embodiment. The present invention can also be applied to a color single plate having a color filter array on the premise of intentional color mixing (filter pair formation), a multi-pixel interline CCD compatible with moving and still images, and thinning. In this multi-pixel interline CCD, one filter pair is first formed on the vertical transfer path, and then vertical transfer is performed while the charge read voltage is applied to a specific charge read electrode, whereby a line of a plurality of same color filter pairs is formed. Then, the color filter pair of the remaining lines is read out and formed on the vertical transfer path while avoiding color mixing with the previous filter pair, and the charge read voltage is applied to the specific charge read electrode again. By performing vertical transfer, line addition is performed for multiple same color filter pairs, and as a result,
All pixels are read out by line addition of multiple filter pairs of the same color, and the moving image is remarkably improved, such as frame rate improvement, vertical spatial frequency reproducibility improvement, and sensitivity improvement, without interfering with the intended later image processing. The image quality can be improved.

That is, the above operation is also applied to a color single plate of a color filter array capable of easily generating luminance and color difference signals by line mixing, a moving image still image combined and thinning compatible multi-pixel interline interlaced scan CCD, Without affecting the subsequent image processing,
All pixels can be read out by adding a plurality of same color filter pairs.

Next, FIG. 32 shows the fifth embodiment of the present invention.
It will be described with reference to FIGS. The configuration of the fifth embodiment is similar to that of the first embodiment, and the configuration diagram is the same as that of FIG. 1. However, in the present embodiment, as shown in the internal structure of FIG. The present invention is applied to a so-called color difference line sequential method (complementary color method) thinning compatible interline interlaced scan CCD.

That is, in the fifth embodiment, C
The CD is a color interline type interlaced scan CCD. The CCD 2 is characterized by both a still image and a moving image, and has a significantly larger number of pixels than a CCD dedicated for moving images. Therefore, when shooting a still image, all pixels are read individually by using a mechanical shutter together. By mixing pixels during shooting, all pixels are
It can be read at twice the frame rate. In addition, this color filter array can facilitate subsequent image processing by intentionally mixing filter pixels of different colors during a moving image. That is, by adding the vertically adjacent pixels together, Ye + Mg, Y
Four kinds of filter pair signals of e + G, Cy + G and Cy + Mg can be taken out. Then, (Ye + Mg) + (Cy + G) = 2R + 3G + 2B≈luminance signal Y1 (Ye + G) + (Cy + Mg) = 2R + 3G + 2B≈luminance signal Y2 (Cy + G) − (Ye + Mg) = G−2R ≈color difference signal Cr (Ye + G) − (Cy + Mg) = G−2B ≈color difference signal Cb As shown in FIG. , It is very easy to generate an approximate signal of the color difference signal. Therefore, such a color filter array is generally used as a color CCD for movies.
It has become popular as a filter array.

Then, as shown in the internal structure of FIG. 32, the CCD has a photodiode 11 as a photoelectric conversion means.
And the first CC connected to these photodiodes 11.
A vertical transfer path 12 which is D and a vertical transfer path gate signal wiring 13 connected to each of the vertical transfer paths 12 are provided. Further, in the figure, an arrow 14 indicates a positive direction which is a vertical transfer direction to a horizontal transfer path direction which is a second CCD (not shown).

Further, the photodiodes 11 respectively form pixels and are two-dimensionally arranged in a predetermined pattern. In the present embodiment, the color filters are arranged in the color difference line sequential system (complementary color system) as described above. Then, the combination of the color filters in a predetermined column becomes Ye, Mg, Ye, G ... And M
g and G are located on even-numbered horizontal lines. The combination of the color filters in the columns adjacent to this column is Cy, Mg, Cy, G ... And Mg and G are located on even-numbered horizontal lines.

The charges accumulated in the photodiodes 11 are read out to the vertical transfer path 12 side by applying a charge read pulse, which is a charge read voltage having a positive potential, to the gate electrodes of the vertical transfer paths 12 adjacent to each other. Be done. And
As shown in FIG. 32, the combination of the gate electrodes of the vertical transfer paths accompanied by such charge reading operation of the CCD is
There are 6 systems of V1C, V3A, V3B, V3C, and the electrodes of these 6 systems have a gate electrode V for exclusive use of vertical transfer without charge read operation
In addition to 2, V4, there are a total of eight vertical transfer path gate electrodes, each of which is connected to the vertical transfer path gate signal line 13.

Although the CCD of the above-mentioned embodiment shows the case of 4-line addition (addition of two pairs of the same color filter pair) as an example, actually, the electrodes corresponding to V1A and V3A are considered in the color filter. However, CCDs with various line addition numbers can be realized depending on how many lines are arranged. Furthermore, no matter how the number of lines added increases, the number of vertical transfer gate electrodes does not increase.

In this embodiment, the signal read operation is the same as that in the first embodiment when a still image is picked up.
In the (still image mode), one screen is divided into two fields, an even line and an odd line, and all pixels are read independently.
On the other hand, at the time of shooting a moving image (moving image mode), the above filter pairs are added together while avoiding color mixture with other filter pairs, and all pixel signals are read out at a high speed at a quadruple frame rate.

The operation at the time of capturing a still image is to read all pixels independently as in the above-mentioned embodiments, and the description thereof will be omitted.

A mode of reading out all the pixels by adding two pairs of filters of the same color when shooting a moving image will be described below with reference to FIG. 33 to FIG. 35. That is, although FIG. 33 and FIG. 34 describe the state of charge reading and vertical transfer in the leftmost column in FIG. 32, the same applies to all other columns including adjacent columns in the following description. It is assumed that the operation is occurring. That is, charge reading and vertical transfer are performed in horizontal line units. In addition, FIG.
The voltage waveforms of the vertical transfer path gate signals denoted by V1A to V4 shown in FIG. 34 and the voltage waveforms of the vertical transfer path gate signals denoted by V1A to V4 shown in FIG. 34 are the same. On the other hand, FIG. 33 shows the first half part and FIG. 34 shows the second half part of the waveform showing the potential state of the vertical transfer path with A to U shown in the direction orthogonal to this voltage waveform.

First, as an initial state, the charge transfer pulse 71 is added only to V3C from the state in which each vertical transfer path gate signal and potential state are shown in FIG. 33A, as shown in FIG. 33B, and Mg ( All the charges on the line where (magenta) exists are read out to the vertical transfer path. Next, C in FIG.
As shown in FIG. 33, a predetermined voltage is applied to V1A to V4 while the application of the V3C charge read pulse is stopped, and C to C in FIG.
As indicated by E, 1/2 stages of vertical transfer, that is, reverse transfer is performed in the direction opposite to the horizontal transfer path direction. Next, as shown in F of FIG. 33, a charge read pulse is applied to V1A and V1B.
Then, the charges of Mg and Ye (yellow) are added together to form the filter pair signal Mg + Ye. Next, as shown in G of FIG. 33, after the application of the charge read pulse of V1B is stopped while the charge read pulse is being applied to V1A, as shown in H to J of FIG. Vertical transfer, that is, reverse transfer is performed in the direction. Then, since the potential well is deep under the electrode of V1A which exists every eight lines, two pairs of filter pair signals Mg + Ye of the same color are mixed in the charge holding portion under V1A. That is, in this charge holding portion, the pixel signal charges for four pixels are added. After this, FIG. 33K and FIG.
As indicated by K in FIG. 4, when the application of the charge read pulse of V1A is stopped, two filter pair signals of the same color are added and held under the electrode of V1A. Further, from this state, as shown in L of FIG. 34, a charge read pulse is applied to V1C to read the charge of Ye above G (green). Then, as shown in M to O of FIG. 34, application of the charge read pulse of V1C is stopped, and vertical transfer is performed by 1/2 step in the horizontal transfer path direction, that is, in the positive direction, and then is shown in P of FIG. As described above, a charge read pulse is applied to V3A and V3B. Then, the charges of G and Ye are added together to form the filter pair signal G + Ye. Furthermore, in this state, FIG.
As indicated by Q in FIG. 4, after the application of the charge read pulse of V3B is stopped while the charge read pulse is applied to V3A, as shown in R to T of FIG. Vertical transfer is performed for two stages. Then, since the potential well is deep under the V3A electrode that exists every 8 lines, two filter pair signals G of the same color G
+ Ye is mixed in the charge holding portion under V3A. That is, in this charge holding portion, the pixel signal charges for four pixels are added. After that, as shown in U of FIG. 34, when the application of the charge read pulse of V3A is stopped, two filter pair signals of the same color are added and held under the electrode of V3A.

Thereafter, as shown in the situation of the pixels read out in FIG. 35, first, the charges (G0 + Ye1) + of the vertical transfer path are first formed.
(G4 + Ye5) is transferred to the horizontal transfer path and horizontally transferred. After that, the charges are vertically transferred by three stages and the charges (Mg2 + Ye3) + (Mg6 +
Ye7) is read out to the horizontal transfer path and horizontally transferred. After that,
Similarly, one-stage vertical transfer, horizontal transfer, three-stage vertical transfer,
It is possible to read out all pixel charge signals line-mixed at a frame rate four times that of a still image by repeating horizontal transfer.

In this embodiment, the pixel mixture is realized by performing the reverse transfer on the vertical transfer path. However, in the sixth embodiment shown below, as in the above-mentioned respective embodiments. , Pixel mixing is possible only by the transfer in the forward direction on the vertical transfer path without the reverse transfer, and in this case, the mixing of the same color filter pair signals can be realized, that is, all the pixel mixing can be performed only by the vertical transfer in the positive direction. C that realizes and controls image processing etc.
Line order can be compensated by components outside the CD. Further, also in this embodiment, similarly to the second embodiment, the pixel mixture on the odd line side can be performed on the horizontal transfer path.

Next, FIG. 36 shows a sixth embodiment of the present invention.
38 to FIG. 38.

Then, the CCD 2 of the sixth embodiment
The basic operation including the internal structure of the CCD and the driving of the CCD 2 is shown in FIG.
The operation is the same as that of the fifth embodiment shown in FIG. 2, and the description of the operation in the still image mode is omitted. And in this embodiment,
In the vertical transfer path, charges need only be transferred only in the positive direction, which is the horizontal transfer path direction, and there is no need for reverse transfer. Therefore, it is possible to deal with CCDs in which the transfer efficiency of reverse transfer is significantly reduced, and the versatility can be improved. At the same time, by introducing the addition in the horizontal transfer path, the time required for the read operation can be made slightly shorter than that in the fifth embodiment. Further, in the sixth embodiment, the combination of filter pair addition is changed from that of the fifth embodiment.

Then, the mode of reading out all pixels by adding two pairs of filters of the same color together, such as when shooting a moving image, will be described below with reference to FIGS. 36 to 38, in the state of charge reading and vertical transfer. That is, FIGS. 36 and 37 describe the state of charge reading and vertical transfer in the leftmost column in FIG. 32, but in the following description, the same applies to all other columns including adjacent columns. It is assumed that the operation is occurring. That is, charge reading and vertical transfer are performed in horizontal line units. In addition, FIG.
The voltage waveforms of the vertical transfer path gate signals denoted by V1A to V4 shown in Fig. 37 and the voltage waveforms of the vertical transfer path gate signals denoted by V1A to V4 shown in Fig. 37 are the same. On the other hand, regarding the waveform showing the potential status of the vertical transfer path with A to V shown in the direction orthogonal to this voltage waveform, FIG. 36 shows the first half part, and FIG. 37 shows the second half part.

First, as an initial state, as shown in B of FIG. 36, the charge read pulse 81 is added only to V1C from the state where each vertical transfer path gate signal and potential state are shown in A of FIG. Half, that is, the charge of Ye on the upper side of G is read to the vertical transfer path. Next, as shown in C of FIG. 36, a predetermined voltage is applied to V1A to V4 with the application of the charge read pulse of V1C stopped, and C of FIG.
As shown in D to ½, vertical transfer is performed by ½ stage in the horizontal transfer path direction. Next, as shown in E of FIG. 36, a charge read pulse is applied to V3A and V3B. Then, the charges of Ye and G are added together to form the filter pair signal G + Ye. Then, as shown in F of FIG. 36, after the application of the charge read pulse of V3B is stopped while the charge read pulse is being applied to V3A, as shown in G to I of FIG. Transfer. Then, V3 that exists every 8 lines
Since the potential well is deep under the A electrode, two filter pair signals G + Ye of the same color are mixed in the charge holding unit under V3A. That is, in this charge holding portion, the pixel signal charges for four pixels are added. After this, as shown in J of FIG. 36 and J of FIG.
When the application of the V3A charge read pulse is stopped, two filter pair signals of the same color are added and held under the electrode of V3A. Furthermore, from this state, K- of FIG.
As shown in P, 1.
Vertical transfer is performed for 5 steps, and the filter pair signal is temporarily saved under the V1C electrode. From this state, as shown by Q in FIG. 37, a charge read pulse is applied to V1A and V1B to obtain 1 / ye of Ye.
2, that is, the charge of Ye on the upper side of Mg is read to the vertical transfer path. Then, as shown in R of FIG. 37, these V1A,
The application of the V1B charge read pulse is stopped. Then, FIG.
As shown in S to T in FIG. 7, vertical transfer is performed for ½ stage.
Then, as shown in U of FIG. 37, a charge read pulse is applied to V3C. Then, the charge of Mg is added to Ye, and the filter pair signal Mg + Ye is formed. Next, as indicated by V in FIG. 37, when the application of the V3C charge read pulse is stopped, Mg + Ye is held under the V3C electrode.

After that, as shown in the state of the pixel read out in FIG. 38, first, the charges already on the horizontal transfer path are shown.
After (G0 + Ye1) + (G4 + Ye5) is horizontally transferred and output, the electric charge (Mg2 + Ye3) is output by vertical transfer and horizontal transfer. After that, one-stage vertical transfer, horizontal transfer, three-stage vertical transfer, and horizontal transfer are repeated, and all pixel charge signals line-mixed at a frame rate four times that of a still image can be read out.

Incidentally, also in the sixth embodiment,
Similar to the first embodiment, with respect to the addition signal which is the 5-pixel mixed charge, the positional relationship between the even-numbered line and the odd-numbered line of the charge is reversed. Such a phenomenon is caused by a component outside the CCD 2 arranged in the subsequent stage of the CCD 2 according to the present embodiment, which controls image processing and the like, for example, a line buffer as a processing device capable of recording image data for one line. Is provided, the previously output line signal is temporarily held, the next line signal is allowed to pass first, and the signal of the even line and the signal of the odd line are exchanged, whereby the compensation can be performed.

In the fifth and sixth embodiments described above, the interlaced CCD is described as an example. However, the correlation between the first and second embodiments and the third embodiment, and In consideration of the operation of the embodiment, it is obvious that the present invention can be easily applied to the progressive CCD. By the way, in case of progressive CCD,
The vertical transfer path gate electrode (readout electrode) can be realized by four systems as in the third embodiment.

As described above, in the case of the filter array which is widely adopted in movie cameras and is based on the premise of line mixing, six read electrodes are required, but the effect is the same as that of each of the above embodiments. Similarly, the number of lines to be added can be dealt with, the number of vertical transfer electrodes does not change, and the cost increase can be suppressed.

In each of the above embodiments, the so-called second addition using the horizontal transfer path is configured such that vertical transfer is only forward transfer, or vertical transfer includes not only forward transfer but also reverse transfer. It can be combined with any of the configurations.

Further, also in the configuration in which the vertical transfer is the normal transfer only, it is possible to complete the addition using the vertical transfer path without using the addition using the horizontal transfer path. In the interlaced complementary color line sequential CCD, the electrode wiring different from the configuration of the sixth embodiment is used for the configuration in which the addition is completed by the vertical transfer of the forward transfer.

In each of the above embodiments, for example, 5
The charges of the individual pixels are added to obtain the added charges, but the present invention is not limited to this configuration, and if the charges of two or more pixels that are not continuous in the vertical direction are added, the effect of improving the frame rate and the image quality can be obtained. Can play.

Further, in the above embodiment, the charges of all the pixels are read and used, but it is also possible not to read a part of the charges deviated from the effective pixel, and to not use the read charges.

[0144]

According to the method of driving a solid-state image pickup device of the first aspect, among the plurality of pixels arranged in a predetermined pattern, the charges of the plurality of pixels of the first color are first transferred. Read out to the path and read out and hold the charge of a specific pixel,
It is possible to transfer the read charges of the other pixels, add the transferred charges to the held charges, and generate a first added charge by adding a plurality of charges of the pixels of the first color. Next, transfer and selective charge reading are combined so as not to add to the first added charge, and a plurality of charges of the pixel of the second color are read to the first transfer path, and the charge of the pixel of the first color is read. Similar to the charge, the charges can be added in the first transfer path, or read from the first transfer path to the same position in the second transfer path and added to generate the second added charge. Then, by transferring and outputting the first and second added charges through the second transfer path, the pixels are thinned out and the frame rate can be improved as compared with the state where all the pixels are sequentially read and output. Further, thinning out of pixels can be performed by reading out all pixels and adding a plurality of charges of pixels of the same color, so that the image quality can be easily improved as compared with a configuration in which pixels are selectively read out.

According to the solid-state image pickup device driving method of the second aspect, in addition to the effect of the first aspect, the first added charge and the second added charge can be output in a desired order, and the subsequent process Can be easily processed.

According to the driving method of the solid-state image pickup device of the third aspect, in addition to the effect of the first aspect, the operation of reading and adding charges to the first transfer path can be performed in a relatively short time.

According to the solid-state image pickup device driving method of the fourth aspect, in addition to the effect of any one of the first to third aspects,
In the first adding step, the charge read voltage is applied to the plurality of charge read electrodes to read the charges of the plurality of pixels to the first transfer path, and then the charge read voltage is applied to the specific charge read electrode, This can be done by performing transfer on the first transfer path.

According to the solid-state image pickup device driving method of the fifth aspect, in addition to the effect of any one of the first to fourth aspects,
It is possible to easily switch between a state in which a high-definition image is output by using all pixels and a mode in which pixels are thinned out and output at high speed.

According to the solid-state image pickup device driving method of the sixth aspect, in addition to the effect of the fifth aspect, a high-definition still image signal can be output and a high frame rate can be realized. A signal for a moving image with improved image quality can be output, and a configuration suitable for an imaging device that switches between still images and moving images and shoots is realized.

According to the image pickup device of the seventh aspect, among the plurality of pixels arranged in a predetermined pattern, the electric charges of the plurality of pixels of the first color are first read out to the first transfer path and specified. A first added charge obtained by transferring the read charges of another pixel while holding and reading the charges of the pixel, adding the transferred charges to the held charges, and adding a plurality of charges of the pixels of the first color Can be generated. Next, a plurality of charges of the second color pixel are read out to the first transfer path so as not to be added to the first added charge, and the first transfer path is read in the same manner as the charge of the first color pixel. , Or read from the first transfer path to the same position on the second transfer path and add them to generate a second added charge. Then, by transferring and outputting the first and second added charges through the second transfer path, the pixels are thinned out and the frame rate can be improved as compared with the state where all the pixels are sequentially read and output. Further, thinning out of pixels can be performed by reading out all pixels and adding a plurality of charges of pixels of the same color, so that the image quality can be easily improved as compared with a configuration in which pixels are selectively read out.

According to the image pickup apparatus of the eighth aspect, in addition to the effect of the seventh aspect, since the processing means for changing the order of the output signals is provided, addition is performed in the first transfer path and the second transfer path. It is not always necessary to arrange the order of the first added charges and the second added charges that are output. Therefore, in each transfer path, it is sufficient to transfer the charges only in one direction,
Since it is not necessary to transfer in the reverse direction, it is possible to cope with a CCD having a low transfer efficiency in the transfer in the reverse direction, and the versatility can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an image pickup apparatus of the present invention.

FIG. 2 is a partial explanatory view showing an internal structure of a CCD of the image pickup device of the same.

FIG. 3 is an explanatory diagram showing a still image mode of the above-described CCD driving method.

FIG. 4 is an explanatory diagram showing a still image mode of a driving method of the same as above.

FIG. 5 is an explanatory diagram showing a moving image mode of a driving method of a comparative example of the above CCD.

FIG. 6 is an explanatory view showing a moving image mode of a driving method of the same as above.

FIG. 7 is an explanatory diagram showing a moving image mode of a driving method of the same as above.

FIG. 8 is an explanatory view showing a moving image mode of the driving method of the same as above.

9 is an explanatory diagram following FIG. 8 of the above.

FIG. 10 is an explanatory diagram following FIG. 9 of the above.

FIG. 11 is an explanatory diagram showing an outline of a still image mode of the above CCD.

FIG. 12 is an explanatory diagram showing a moving image mode of a comparative example of the above CCD.

FIG. 13 is an explanatory diagram showing an outline of line read addition in a moving image mode of the CCD.

FIG. 14 is a schematic explanatory diagram of line readout addition in a moving image mode showing the second embodiment of the image pickup apparatus of the present invention.

FIG. 15 is an explanatory diagram showing a moving image mode of the above CCD.

16 is an explanatory diagram following FIG. 15 of the above.

FIG. 17 is an explanatory diagram showing a moving image mode of the above CCD.

FIG. 18 is an explanatory diagram following FIG. 17 of the above.

FIG. 19 is an explanatory diagram following FIG. 18 of the above.

FIG. 20 is an explanatory diagram of a part of the internal structure of the CCD showing the third embodiment of the imaging device of the invention.

FIG. 21 is an explanatory diagram showing a still image mode of the same CCD.

FIG. 22 is an explanatory diagram showing a moving image mode of the above CCD.

FIG. 23 is an explanatory diagram following FIG. 22 above.

FIG. 24 is an explanatory diagram showing a moving image mode of the above CCD.

25 is an explanatory diagram following FIG. 24 of the above.

FIG. 26 is an explanatory diagram following FIG. 25 above.

FIG. 27 is an explanatory diagram showing a moving image mode of a CCD showing a fourth embodiment of the image pickup device of the present invention.

28 is an explanatory diagram continued from FIG. 27 of the same.

FIG. 29 is an explanatory diagram showing a moving image mode of the above CCD.

FIG. 30 is an explanatory diagram following FIG. 29 of the above.

FIG. 31 is an explanatory diagram that follows FIG. 30 above.

FIG. 32 is an explanatory diagram of a part of the internal structure of the CCD showing the fifth embodiment of the image pickup device of the invention.

FIG. 33 is an explanatory diagram showing a moving image mode of the above CCD.

FIG. 34 is an explanatory diagram following FIG. 28 above.

FIG. 35 is an explanatory diagram showing an outline of line readout addition in a moving image mode of the CCD.

FIG. 36 is an explanatory diagram showing a moving image mode of the CCD showing the sixth embodiment of the image pickup apparatus of the present invention.

FIG. 37 is an explanatory diagram following FIG. 28 above.

FIG. 38 is an explanatory diagram showing an outline of line reading addition in a moving image mode of the same as above CCD.

[Explanation of symbols] 1 Imaging device 2 CCD as a solid-state image sensor 3 CCD drive circuit as drive circuit 11 Photodiode as photoelectric conversion means 12 Vertical transfer path as the first transfer path 31a, 31b Charge read pulse as charge read voltage 33 charge 34 5 pixel mixed charge as the first added charge 44 5 pixel mixed charge as second added charge V1A, V1B, V3A, V3B charge readout electrode

Claims (8)

[Claims] 1. A plurality of pixels, each of which has a photoelectric conversion means and in which a first color and a second color are arranged in a predetermined pattern, and a plurality of first transfer paths for reading and transferring charges of the pixels.
A method of driving a solid-state imaging device, comprising: a second transfer path that reads out, transfers, and outputs the charges transferred by the first transfer paths, wherein the charges of the pixels of the first color are transferred to the first transfer path. A plurality of read out charges are transferred to the transfer path, while the read out charge of a specific pixel is maintained and the read out charge is held, the read charges of other pixels are transferred, and the transferred charge is added to the held charge, A first addition step of generating a first added charge by adding a plurality of charges of pixels of one color; and a state in which the first added pixel is removed from a position where the charges of the pixels of the second color are read out. A plurality of charges of the pixels of the second color are read to the first transfer path, and a plurality of charges of the pixels of the second color are read out to the first transfer path and the second transfer path.
A second addition step of adding a plurality of charges of the pixels of the second color to generate a second addition charge by adding at least one of the transfer paths of the first addition charge, and the first addition charge and the second addition charge. And a summing and outputting step of transferring and outputting by the second transfer path. 2. The first addition step and the second addition step,
The method for driving a solid-state imaging device according to claim 1, wherein the method is performed while transferring the charges read out to the first transfer path in a forward direction and a reverse direction. 3. The driving of the solid-state imaging device according to claim 1, wherein the second adding step is performed by reading out a plurality of charges of the pixels of the second color at a predetermined position of the second transfer path. Method. 4. The first transfer path comprises a charge-coupled device having a charge read electrode for each pixel, and the charge is read and held by applying a charge read voltage to the charge read electrode. 4. The method for driving a solid-state image pickup device according to claim 1, which is characterized in that. 5. A first drive mode in which a first addition step, a second addition charge, and an addition output step are performed, and charges of each pixel are individually read to a first transfer path, and the read charges are individually read. 5. The method for driving a solid-state image pickup device according to claim 1, wherein a second drive mode in which the transfer is performed to the second transfer path and the second drive mode is output from the second transfer path is switched. 6. The solid-state image pickup according to claim 5, wherein the first driving mode is a moving image mode for shooting a moving image, and the second driving mode is a still image mode for shooting a still image. Device driving method. 7. A solid-state image sensor, and a drive circuit for driving the fixed image sensor, wherein the solid-state image sensor includes photoelectric conversion means, and a first color and a second color are arranged in a predetermined pattern. A plurality of first transfer paths for reading out and transferring the electric charges of the pixels, and a second circuit for reading out, transferring, and outputting the electric charges transferred by the first transfer paths. The drive circuit reads out a plurality of charges of the pixels of the first color to the first transfer path, maintains a state of reading out charges of a specific pixel, and holds the read out charges. Transferring the read charges of other pixels, adding the transferred charges to the held charges, and generating a first added charge by adding a plurality of charges of the pixels of the first color, The charge of the pixel of the second color is read out from the addition pixel A plurality of charges of the pixels of the second color are read out to the first transfer path in a state where the charges of the pixels of the second color are removed from the first transfer path and the first transfer path. Two
Of at least one of the transfer paths to generate a second added charge by adding a plurality of charges of pixels of the second color, and the first added charge and the second added charge are transferred to the second transfer. An imaging device characterized by being transferred on the road and output. 8. The image pickup apparatus according to claim 7, further comprising a processing unit capable of changing the order of the first added charge and the second added charge output from the solid-state image pickup device.