JP4848349B2 - Imaging apparatus and solid-state imaging device driving method - Google Patents

Description

  The present invention includes a charge transfer type solid-state imaging device that includes a large number of photoelectric conversion elements, reads out and transfers charges generated by the large number of photoelectric conversion elements to a charge transfer path, and outputs a signal corresponding to the transferred charges. The present invention also relates to an imaging apparatus including a driving unit that drives the solid-state imaging element.

  Conventionally, a photoelectric conversion element in which an R color filter that transmits red (R) light is provided above the light receiving surface, and a photoelectric conversion element in which a G color filter that transmits green (G) light is provided above the light receiving surface A photoelectric conversion element in which a B color filter that transmits blue (B) light is provided above the light receiving surface, and a photoelectric conversion element in which a luminance filter having spectral characteristics correlated with the luminance component of the light is provided above the light receiving surface. A solid-state imaging device in which conversion elements are two-dimensionally arranged has been proposed (see, for example, Patent Documents 1 to 3).

JP-A-11-355790 JP 2007-258686 A JP 2003-318375 A

  In the solid-state imaging device disclosed in Patent Literatures 1 to 3, for example, in the first field, the color component charge is read from the photoelectric conversion device provided with the color filter above the light receiving surface, and the luminance filter is used in the second field. Can read out the luminance component charge from the photoelectric conversion element provided above the light receiving surface and process the image pickup signal obtained in each field, thereby generating high-quality image data.

  The present invention is a solid-state imaging device capable of reading out all charges in two fields as described in Patent Documents 1 to 3, and has a configuration capable of generating color image data in only one field. A new driving method for a solid-state imaging device is proposed.

  An image pickup apparatus according to the present invention includes a large number of photoelectric conversion elements, reads out and transfers charges generated by the large number of photoelectric conversion elements to a charge transfer path, and outputs a signal corresponding to the transferred charges. An imaging apparatus including an imaging element, wherein the plurality of photoelectric conversion elements include a first photoelectric conversion element group and a second photoelectric conversion element group, and the first photoelectric conversion element group includes color image data. A first driving unit configured to read out the electric charge from the first photoelectric conversion element group and output a signal corresponding to the electric charge. And the second driving for separately performing the second driving for reading the charge from the second photoelectric conversion element group and outputting a signal corresponding to the charge, the first driving and the second driving In any of the driving Of the charges read to the charge transferring path, a drive means for driving to transfer the mixed charges of adjacent same-color component in the charge transfer path.

  In the imaging device of the present invention, the second photoelectric conversion element group is configured only by a luminance detection photoelectric conversion element in which a luminance filter having a correlation with a luminance component is provided above the light receiving surface.

  In the imaging apparatus according to the aspect of the invention, when the driving unit performs the two-field driving, in the second driving, among the charges read to the charge transfer path, adjacent charges of the same color component are placed on the charge transfer path. Transfer with mixing.

  In the imaging apparatus of the present invention, the plurality of photoelectric conversion elements are arranged in a square lattice pattern on a semiconductor substrate, and the first photoelectric conversion element group and the second photoelectric conversion element group are arranged in a checkered pattern. Has been.

  In the imaging device of the present invention, the photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are orthogonal to the row direction on the semiconductor substrate, respectively. The first photoelectric conversion element group and the second photoelectric conversion element group are ½ of the arrangement pitch of each photoelectric conversion element in the row direction and the column. They are displaced in the direction.

  In the imaging apparatus of the present invention, the second photoelectric conversion element group includes a photoelectric conversion element that detects light of a color component necessary for generating color image data, and the first photoelectric conversion element The photoelectric conversion elements included in the group and the photoelectric conversion elements included in the second photoelectric conversion element group are respectively arranged in a square lattice pattern in a row direction on the semiconductor substrate and in a column direction perpendicular thereto. An arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group and an arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group, Each is the same, and the first photoelectric conversion element group and the second photoelectric conversion element group are arranged to be shifted in the row direction and the column direction by 1/2 of the arrangement pitch of the photoelectric conversion elements. .

  In the image pickup apparatus of the present invention, the charge transfer path of the solid-state image sensor includes a vertical charge transfer path and a horizontal charge transfer path, and the solid-state image sensor is interposed between the vertical charge transfer path and the horizontal charge transfer path. A charge storage unit that temporarily stores charges transferred through the vertical charge transfer path, and an electrode that applies a voltage to the charge storage unit; The electrode above the charge storage section between the vertical charge transfer path from which charges are read and the horizontal charge transfer path, and the vertical charge transfer path from which charges from the second photoelectric conversion element group are read. A voltage can be independently applied to each of the electrodes above the charge storage unit between the horizontal charge transfer paths, and the first photoelectric conversion element group and the second photoelectric conversion element group, Read signal from only one of Control means for controlling the voltage of the electrode so as not to transfer the charge from the vertical charge transfer path from which charges are read out from the photoelectric conversion element group which does not need to read the signal when driving. Is provided.

  In the image pickup apparatus of the present invention, the color filter array provided above the photoelectric conversion elements constituting the first photoelectric conversion element group is a Bayer array.

  The solid-state imaging device driving method of the present invention includes a large number of photoelectric conversion elements, and charges generated by the large number of photoelectric conversion elements are read and transferred to a charge transfer path, and a signal corresponding to the transferred charges is output. A method of driving a transfer-type solid-state imaging device, wherein the plurality of photoelectric conversion elements are composed of a first photoelectric conversion element group and a second photoelectric conversion element group, and the first photoelectric conversion element group is And a photoelectric conversion element that detects light of a color component necessary for generating color image data, and reads out the charge from the first photoelectric conversion element group and outputs a signal corresponding to the charge. When performing the two-field drive separately performing the first drive and the second drive for reading out the charge from the second photoelectric conversion element group and outputting a signal corresponding to the charge, the first drive And one of the second drives There are, of charges read to the charge transfer path, and transfers the mixed charges of adjacent same-color component in the charge transfer path.

  In the solid-state imaging device driving method according to the present invention, the second photoelectric conversion element group includes only a luminance detection photoelectric conversion element in which a luminance filter having a correlation with a luminance component is provided above the light receiving surface.

  In the driving method of the solid-state imaging device according to the present invention, when performing the two-field driving, in the second driving, among the charges read to the charge transfer path, adjacent charges of the same color component are transferred on the charge transfer path. Mix and transfer.

  In the method for driving a solid-state imaging device according to the present invention, the plurality of photoelectric conversion elements are arranged in a square lattice pattern on a semiconductor substrate, and the first photoelectric conversion element group and the second photoelectric conversion element group include: It is arranged in a checkered pattern.

  According to the solid-state imaging device driving method of the present invention, the photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are each in the row direction on the semiconductor substrate. And the first photoelectric conversion element group and the second photoelectric conversion element group are ½ the row of the arrangement pitch of the photoelectric conversion elements. It is shifted in the direction and the column direction.

  In the solid-state imaging device driving method of the present invention, the second photoelectric conversion element group includes a photoelectric conversion element that detects light of a color component necessary for generating color image data. The photoelectric conversion elements included in the photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are respectively arranged in a square lattice pattern in the row direction on the semiconductor substrate and in the column direction orthogonal thereto. An arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group, and a color filter provided above the photoelectric conversion elements constituting the first photoelectric conversion element group. And the first photoelectric conversion element group and the second photoelectric conversion element group are shifted in the row direction and the column direction by a half of the arrangement pitch of the photoelectric conversion elements. Has been placed.

  In the solid-state image sensor driving method according to the present invention, the charge transfer path of the solid-state image sensor includes a vertical charge transfer path and a horizontal charge transfer path, and the solid-state image sensor includes the vertical charge transfer path and the horizontal charge transfer path. A charge storage unit that temporarily stores the charge transferred through the vertical charge transfer path, and an electrode that applies a voltage to the charge storage unit, the first photoelectric conversion The electrode above the charge storage section between the vertical charge transfer path from which charges from the element group are read and the horizontal charge transfer path, and the vertical from which charges from the second photoelectric conversion element group are read. A voltage can be independently applied to the electrode above the charge storage portion between the charge transfer path and the horizontal charge transfer path, and the first photoelectric conversion element group and the second photoelectric transfer element can be applied. Only one of the conversion elements When performing driving to read out the signal, the voltage of the electrode is set so as not to transfer the charge from the vertical charge transfer path from which charges are read from the photoelectric conversion element group that does not need to read out the signal to the horizontal charge transfer path. Control.

  In the solid-state imaging device driving method of the present invention, the color filter array provided above the photoelectric conversion elements constituting the first photoelectric conversion element group is a Bayer array.

  According to the present invention, there is provided a new driving method for a solid-state imaging device that can read out all charges in two fields and has a configuration capable of generating color image data in only one field. can do.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a digital camera which is an example of an imaging apparatus for explaining a first embodiment of the present invention.
The imaging system of the digital camera shown in the figure includes a photographic lens 1, a CCD type solid-state imaging device 5, a diaphragm 2 provided therebetween, an infrared cut filter 3, and an optical low-pass filter 4.

  A system control unit 11 that performs overall control of the electrical control system of the digital camera controls the flash light emitting unit 12 and the light receiving unit 13 and controls the lens driving unit 8 to adjust the position of the photographing lens 1 to the focus position and zoom. The exposure amount is adjusted by adjusting the aperture amount of the aperture 2 via the aperture drive unit 9.

  Further, the system control unit 11 drives the solid-state imaging device 5 via the imaging device driving unit 10 and outputs a subject image captured through the photographing lens 1 as a color signal. An instruction signal from the user is input to the system control unit 11 through the operation unit 14.

  The electric control system of the digital camera further includes an analog signal processing unit 6 that performs analog signal processing such as correlated double sampling processing connected to the output of the solid-state imaging device 5, and RGB output from the analog signal processing unit 6. And an A / D conversion circuit 7 for converting the color signals into digital signals, which are controlled by the system control unit 11.

  Furthermore, the electric control system of this digital camera generates image data by performing main memory 16, memory control unit 15 connected to main memory 16, interpolation calculation, gamma correction calculation, RGB / YC conversion processing, and the like. A digital signal processing unit 17, a compression / decompression processing unit 18 that compresses image data generated by the digital signal processing unit 17 into a JPEG format or decompresses compressed image data, and a digital signal processing unit 17 that integrates photometric data. The integration unit 19 for obtaining the gain of white balance correction performed by the camera, the external memory control unit 20 to which the removable recording medium 21 is connected, and the display control unit 22 to which the liquid crystal display unit 23 mounted on the back of the camera is connected. These are connected to each other by a control bus 24 and a data bus 25, and are controlled by commands from the system control unit 11. That.

FIG. 2 is a schematic plan view showing a configuration example of the solid-state imaging device 5 shown in FIG.
The solid-state imaging device 5 is a photoelectric conversion element 51R (indicated by the letter “R” in the figure) that detects R light arranged in a square lattice pattern in the row direction X on the semiconductor substrate 50 and the Y direction perpendicular thereto. Photoelectric conversion element 51G for detecting G light (characterized with “G” in the figure), photoelectric conversion element 51B for detecting B light (characterized with “B” in the figure) And a photoelectric conversion element 51W that detects luminance components of light arranged in a square lattice pattern in the row direction X on the semiconductor substrate 50 and in the Y direction perpendicular thereto. W photoelectric conversion element group consisting of “W” inside, and these are shifted in the row direction X and the column direction Y by about ½ of the respective photoelectric conversion element arrangement pitch. It is arranged at the position. The arrangement pitch of each photoelectric conversion element of the RGB photoelectric conversion element group and each photoelectric conversion element of the W photoelectric conversion element group is the same.

  A color filter is provided above each photoelectric conversion element of the RGB photoelectric conversion element group, and the arrangement of the color filters is a Bayer array.

  Above each photoelectric conversion element of the W photoelectric conversion element group, a filter having a spectral characteristic correlated with the luminance information of light, that is, a luminance filter is provided. This luminance filter corresponds to an ND filter, a transparent filter, a white filter, a gray filter, or the like, but the configuration in which light is directly incident on the light receiving surface without providing anything above the light receiving surface of the photoelectric conversion element is also possible. It can be said that a filter is provided.

  Each photoelectric conversion element in the RGB photoelectric conversion element group and each photoelectric conversion element in the W photoelectric conversion element group have the same structure.

  The arrangement of each photoelectric conversion element of the RGB photoelectric conversion element group is such that a GR photoelectric conversion element array, which is a photoelectric conversion element array composed of a photoelectric conversion element 51G and a photoelectric conversion element 51R aligned in the column direction Y, and a photoelectric array in the column direction Y. It can be said that BG photoelectric conversion element arrays, which are photoelectric conversion element arrays including conversion elements 51B and 51G, are alternately arranged in the row direction X. In addition, the arrangement of the photoelectric conversion elements of the RGB photoelectric conversion element group is such that the photoelectric conversion element rows, which are photoelectric conversion element rows 51G and photoelectric conversion elements 51B arranged in the row direction X, are arranged in the row direction X. It can also be said that RG photoelectric conversion element rows, which are photoelectric conversion element rows composed of the aligned photoelectric conversion elements 51R and 51G, are alternately arranged in the column direction Y.

  The arrangement of each photoelectric conversion element of the W photoelectric conversion element group can be said to be a plurality of W photoelectric conversion element arrays in the row direction X, which are photoelectric conversion element arrays composed of photoelectric conversion elements 51W arranged in the column direction Y. . In addition, the arrangement of the photoelectric conversion elements of the W photoelectric conversion element group can be said to be a plurality of W photoelectric conversion element rows formed of the photoelectric conversion elements 51W arranged in the row direction X in the column direction Y.

  On the right side of each photoelectric conversion element array, a vertical charge transfer path for transferring charges accumulated in the photoelectric conversion elements constituting each photoelectric conversion element array in the column direction Y corresponding to each photoelectric conversion element array 54 (only part of which is shown in FIG. 2) is formed. The vertical charge transfer path 54 is formed by, for example, n-type impurities injected into a p-well layer formed on an n-type silicon substrate.

  Above the vertical charge transfer path 54, transfer electrodes V <b> 1 to V <b> 8 are formed to which an eight-phase transfer pulse for controlling transfer of charges read out to the vertical charge transfer path 54 is applied by the image sensor driving unit 10. ing.

  The transfer electrodes V1 to V8 are arranged so as to meander between the photoelectric conversion element rows in the row direction X so as to avoid the photoelectric conversion elements constituting them.

  Between each photoelectric conversion element and the vertical charge transfer path 54 corresponding to the photoelectric conversion element, a charge reading unit 55 for reading the charge generated in each photoelectric conversion element to the vertical charge transfer path 54 is provided. The charge readout unit 55 is formed by a part of a p-well layer formed on an n-type silicon substrate, for example. The charge readout unit 55 is provided in the same direction (in the diagonally lower right direction in the drawing) with respect to each photoelectric conversion element.

  A transfer electrode V2 or V6 is formed above the charge reading unit 55 corresponding to the photoelectric conversion element 51W, and the charge generated and accumulated in the photoelectric conversion element 51W is applied to the transfer electrode V2 or V6 by applying a read pulse thereto. Data can be read out to the vertical charge transfer path 54 on the right side of the photoelectric conversion element 51W.

  A transfer electrode V4 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the GB photoelectric conversion element row. By applying a read pulse to the transfer electrode V4, the transfer electrode V4 is applied to each photoelectric conversion element in the GB photoelectric conversion element row. The generated and accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A transfer electrode V8 is formed above the charge reading unit 55 corresponding to each photoelectric conversion element in the RG photoelectric conversion element row. By applying a read pulse to the transfer electrode V8, the transfer electrode V8 is applied to each photoelectric conversion element in the RG photoelectric conversion element row. The generated and accumulated charges can be read out to the vertical charge transfer path 54 on the right side of each photoelectric conversion element.

  A horizontal charge transfer path 57 for transferring the charges transferred through the vertical charge transfer path 54 in the row direction X is connected to the vertical charge transfer path 54. The horizontal charge transfer path 57 is connected to the horizontal charge transfer path 57. Is connected to an output amplifier 58 that converts the charge transferred to a voltage signal and outputs the voltage signal.

  The image sensor driving unit 10 reads out electric charges from the RGB photoelectric conversion element group, outputs a signal corresponding to the electric charges, reads out electric charges from the W photoelectric conversion element group, and outputs a signal corresponding to the electric charges. Two-field driving is performed separately from the second driving. In the two-field drive, in the second drive, the mixed drive that mixes and transfers adjacent charges among the charges read to the vertical charge transfer path 54 on the vertical charge transfer path 54, and the second drive. In FIG. 2, there are two types of normal driving in which adjacent charges among the charges read out to the vertical charge transfer path 54 are transferred on the vertical charge transfer path 54 without being mixed.

Hereinafter, the operation during mixed driving will be described.
When the exposure period ends, the image sensor driving unit 10 applies a readout pulse to the transfer electrodes V4 and V8, and the charges generated in the photoelectric conversion elements of the RGB photoelectric conversion element group correspond to the photoelectric conversion elements. Read to the vertical charge transfer path 54. Then, the charge is transferred to the horizontal charge transfer path 57, the charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom.

  Next, the imaging element driving unit 10 applies a read pulse to the transfer electrodes V2 and V6, and transfers the charges generated in each photoelectric conversion element of the W photoelectric conversion element group to the vertical charge transfer corresponding to each photoelectric conversion element. Read to path 54. Next, the image sensor driving unit 10 mixes two adjacent charges out of the charges read out to the vertical charge transfer path 54 on the vertical charge transfer path 54, and then mixes the mixed charges into the horizontal charge transfer path 57. The charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom.

  When such driving is performed, the solid-state imaging device 5 gives the same number of color signals as the total number of photoelectric conversion elements constituting the RGB photoelectric conversion element group in FIG. 2 and the W photoelectric conversion element group in FIG. And a luminance signal that is half the total number of photoelectric conversion elements constituting the.

  Therefore, after the digital signal processing unit 17 halves the color signal to make it the same number as the luminance signal, the color signal and luminance signal of the color that does not exist at the position where the color signal is present are changed to the surrounding color. All the photoelectric conversion elements of the solid-state imaging device 5 are subjected to signal processing that interpolates using a signal and a luminance signal, and interpolates a color signal that is not at that position using a surrounding color signal at a position where the luminance signal exists. Color image data composed of half the number of pixel data can be generated.

  Image data having such a number of pixels can also be generated from, for example, an imaging signal obtained by thinning a color signal and a luminance signal obtained by performing normal driving by half. The advantage of mixed driving is that the luminance signal level can be increased because the luminance signal is increased to 1/2 because the luminance signal is not decimated and the total number is halved. It is to be able to generate an image with a high feeling.

  As described above, since the number of pixels of the color image data generated when mixing driving is performed is smaller, the image sensor driving unit 10 performs the above-described mixing driving or normal driving depending on the resolution set by the user. By selecting whether or not to perform the optimum driving according to the photographing conditions can be performed. Further, the mixed drive can shorten the drive time of the second field compared to the normal drive. For this reason, when high-speed driving is required, such as in continuous shooting mode, it is possible to select and execute mixed driving. Further, since the driving time can be shortened, power consumption can be reduced.

  In the above description, when signals are output from the RGB photoelectric conversion element group in the mixed drive, color signals are output from all the photoelectric conversion elements constituting the RGB photoelectric conversion element group, and color is processed by subsequent signal processing. The number of signals is halved. However, the present invention is not limited to this, and when signals are output from the RGB photoelectric conversion element group, thinning driving may be performed in which charges are thinned out and read. In this case, further high speed driving is possible.

  When thinning driving is performed, it is preferable to change the number of luminance signals mixed according to the thinning number of color signals. For example, when driving to thin out the color signal to ¼ and output it, the adjacent four charges out of the luminance component charges read out to the vertical charge transfer path 54 are mixed and transferred. Just do it. Thus, by changing the number of luminance component charges according to the number of thinned out color signals, the sense of resolution can be improved while driving faster.

  In the above description, the charge read from the W photoelectric conversion element group is mixed by the vertical charge transfer path 54 in the mixed drive. However, instead of the charge read from the W photoelectric conversion element group, the RGB photoelectric conversion element is used. Of the charges read from the group, adjacent charges of the same color component may be mixed and transferred by the vertical charge transfer path 54. In this case, color image data is generated after thinning the luminance signal so as to be the same as the total number of color signals, or charge is thinned out from the W photoelectric conversion element group according to the number of mixed color component charges. You may make it read.

  In the above description, an example in which the color filter provided above the photoelectric conversion elements constituting the RGB photoelectric conversion element group is a primary color filter is shown. However, this color filter may be any filter that can generate color image data only from signals obtained from the RGB photoelectric conversion element group. For example, a complementary color filter may be used.

(Second embodiment)
The mixing drive described in the first embodiment is not limited to the solid-state imaging device having the configuration shown in FIG. 2, but is a photoelectric conversion device including a photoelectric conversion device that detects light of a color component necessary for generating color image data. Any solid-state imaging device can be applied as long as it includes a group and a photoelectric conversion element group different from the group and can read signals from these photoelectric conversion element groups separately. In the present embodiment, a configuration example other than the configuration shown in FIG. 2 will be described as such a solid-state imaging device.

FIG. 3 is a schematic plan view showing a configuration example of a solid-state imaging device mounted on the imaging device according to the second embodiment of the present invention. In FIG. 3, the same components as those shown in FIG.
The solid-state image pickup device 5 shown in FIG. 3 is a color filter having a Bayer arrangement as a filter provided above the photoelectric conversion devices 51W constituting the W photoelectric conversion device group of the solid-state image pickup device 5 shown in FIG. Hereinafter, a photoelectric conversion element group including photoelectric conversion elements provided with the color filter above is referred to as an rgb photoelectric conversion element group.

  As shown in FIG. 3, the rgb photoelectric conversion element group includes a photoelectric conversion element 51r provided with an R color filter above, a photoelectric conversion element 51g provided with a G color filter above, and a B color filter upward. And a provided photoelectric conversion element 51b.

  Each photoelectric conversion element in the RGB photoelectric conversion element group and each photoelectric conversion element in the rgb photoelectric conversion element group have different detection sensitivities. For example, the detection sensitivity of each photoelectric conversion element in the RGB photoelectric conversion element group is lower. Yes. To change the detection sensitivity of the photoelectric conversion element, the area of the light receiving surface of the photoelectric conversion element may be changed, or the light collection area may be changed by a microlens provided above the photoelectric conversion element, The exposure time may be changed for each of the two photoelectric conversion elements. Since these methods are publicly known, description thereof is omitted.

  The details of the photoelectric conversion element array shown in FIG. 3 are also disclosed in Japanese Patent Application Laid-Open No. 2004-055586, so please refer to this.

Hereinafter, the operation during mixed driving will be described.
When the exposure period ends, the image sensor driving unit 10 applies a readout pulse to the transfer electrodes V4 and V8, and the charges generated in the photoelectric conversion elements of the RGB photoelectric conversion element group correspond to the photoelectric conversion elements. Read to the vertical charge transfer path 54. Then, the charge is transferred to the horizontal charge transfer path 57, the charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom.

  Next, the image sensor driving unit 10 applies a read pulse to the transfer electrodes V2 and V6, and transfers the charge generated in each photoelectric conversion element of the rgb photoelectric conversion element group to the vertical charge transfer corresponding to each photoelectric conversion element. Read to path 54. Next, the image sensor driving unit 10 mixes two adjacent charges of the same color component on the vertical charge transfer path 54 out of the charges read out to the vertical charge transfer path 54, and then converts the mixed charge into a horizontal charge. The charge is transferred to the transfer path 57, the charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom.

  When such driving is performed, the solid-state imaging device 5 gives the same number of color signals as the total number of photoelectric conversion elements constituting the RGB photoelectric conversion element group in FIG. 3, and the rgb photoelectric conversion element group in FIG. As a result, a color signal that is half the total number of photoelectric conversion elements constituting the signal is obtained.

  Therefore, the digital signal processing unit 17 thins out a color signal (referred to as RGB color signal) obtained from the RGB photoelectric conversion element group to ½, and a color signal (referred to as rgb color signal) obtained from the rgb photoelectric conversion element group. ), The RGB color signal and the rgb color signal adjacent to the same color pixels are combined to expand the dynamic range, and the color signal is interpolated using the combined color signal. By performing the signal processing to be performed, it is possible to generate color image data including pixel data that is ¼ of the total number of photoelectric conversion elements of the solid-state imaging element 5.

  As described above, even with the configuration in which the W photoelectric conversion element group is changed to the rgb photoelectric conversion element group, the mixed driving described in the first embodiment can be applied, and high speed driving, high resolution, wide A digital camera that achieves a dynamic range and low power consumption can be provided.

  In the above description, the color filter provided above the photoelectric conversion elements constituting the rgb photoelectric conversion element group is an example of a primary color filter. However, this color filter only needs to be a filter that can generate color image data using only signals obtained from the rgb photoelectric conversion element group. For example, a complementary color filter may be used.

  In the above description, the charges from the RGB photoelectric conversion element group are transferred without being mixed, and the charges from the rgb photoelectric conversion element group are mixed and transferred. good.

(Third embodiment)
In the present embodiment, a photoelectric conversion element group composed of photoelectric conversion elements that detect light of a color component necessary for generating color image data and a photoelectric conversion element group different from the photoelectric conversion element group are provided. Another configuration example of the solid-state imaging device capable of separately reading the signals from will be described.

FIG. 4 is a schematic plan view showing a configuration example of a solid-state imaging device mounted on the imaging apparatus according to the third embodiment of the present invention. FIG. 4 shows only the arrangement of the photoelectric conversion elements.
The solid-state imaging device shown in FIG. 4 includes a photoelectric conversion element 61R provided with an R color filter above, a photoelectric conversion element 61G provided with a G color filter above, and a photoelectric conversion provided with a B color filter above. The element 61B and the photoelectric conversion element 61W having a luminance filter provided thereon are arranged in a square lattice pattern in the horizontal direction on the semiconductor substrate and in the vertical direction perpendicular thereto. The photoelectric conversion elements 61R, 61G, 61B and the photoelectric conversion element 61W are arranged in a checkered pattern.

  Although not shown in FIG. 4, on the right side of the photoelectric conversion element array composed of photoelectric conversion elements arranged in the vertical direction in FIG. 4, charges generated in the photoelectric conversion elements of this photoelectric conversion element array are vertically aligned. A vertical charge transfer path for transferring is provided, and at the end of the vertical charge transfer path, a horizontal charge transfer path for transferring the charges transferred through the vertical charge transfer path in the horizontal direction is provided. Is provided with an output amplifier that outputs a signal corresponding to the charge transferred through the horizontal charge transfer path.

  The solid-state imaging device shown in FIG. 4 is perpendicular to each photoelectric conversion element so that reading of charges from the photoelectric conversion elements 61R, 61G, and 61B and reading of charges from the photoelectric conversion element 61W can be performed independently. A charge reading region for reading charges is formed in the charge transfer path.

  The details of the solid-state imaging device shown in FIG. 4 are described in Japanese Patent Application Laid-Open No. 2003-318375, so please refer to this.

  Even in the solid-state imaging device having such a configuration, the above-described mixed driving can be applied. That is, the charge is read from the photoelectric conversion elements 61R, 61G, 61B in the first field and transferred, and the charge is read from the photoelectric conversion element 61W in the second field and transferred. These charges may be mixed and transferred on the vertical charge transfer path.

(Fourth embodiment)
In the solid-state imaging device having the configuration described in the first embodiment or the second embodiment, the vertical charge transfer path corresponding to the RGB photoelectric conversion element group and the vertical corresponding to the W photoelectric conversion element group (or rgb photoelectric conversion element group). Separate from the charge transfer path. For this reason, when charges are read out from one photoelectric conversion element group and transferred, no charge exists in the vertical charge transfer path corresponding to the other photoelectric conversion element group. However, since the vertical charge transfer path is driven in the same manner as other vertical charge transfer paths, noise charges such as dark current components are transferred to the horizontal charge transfer path 57 from the vertical charge transfer path. That is, in a state where charges for one line are transferred to the horizontal charge transfer path 57, the arrangement of the charges is a repetition of signal charges and noise charges. If the charge is transferred in the horizontal direction in this state, the noise charge leaks into the signal charge and the SN ratio is deteriorated. Therefore, in the present embodiment, a configuration of a solid-state imaging device for preventing such noise charge leakage will be described.

FIG. 5 is a schematic plan view illustrating a configuration example of a solid-state imaging device mounted on the imaging device according to the fourth embodiment of the present invention. In FIG. 5, the same components as those in FIG.
The solid-state imaging device 5 illustrated in FIG. 5 includes a charge storage unit 60 for temporarily storing charges between the vertical charge transfer path 54 and the horizontal charge transfer path 57 of the solid-state image sensor 5 illustrated in FIG. An electrode 59a for controlling the potential of the charge storage section 60 is provided above the charge storage section 60 connected to the vertical charge transfer path 54 corresponding to each photoelectric conversion element of the RGB photoelectric conversion element group, and W photoelectric conversion is performed. An electrode 59b for controlling the potential of the charge storage unit 60 is provided above the charge storage unit 60 connected to the vertical charge transfer path 54 corresponding to each photoelectric conversion element of the element group.

  A control pulse φLM2 is applied to the electrode 59a, and a control pulse φLM1 is applied to the electrode 59b.

Hereinafter, the operation during mixed driving will be described.
When the exposure period ends, the image sensor driving unit 10 applies a readout pulse to the transfer electrodes V4 and V8, and the charges generated in the photoelectric conversion elements of the RGB photoelectric conversion element group correspond to the photoelectric conversion elements. Read to the vertical charge transfer path 54. Then, the charge is transferred to the horizontal charge transfer path 57 via the charge storage section 60, the charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom. The charges accumulated in the charge accumulation unit 60 can be transferred to the horizontal charge transfer path 57 by setting the control pulses φLM1 and φLM2 to the low level.
When transferring the charge to the horizontal charge transfer path 57, the image sensor driving unit 10 maintains the control pulse φLM1 at the high level and switches only the control pulse φLM2 between the low level and the high level, thereby lowering the electrode 59a. Control is performed so that noise charges accumulated in the charge accumulation unit 60 below the electrode 59 b are not transferred to the horizontal charge transfer path 57 while transferring the color component charges accumulated in the charge accumulation unit 60 to the horizontal charge transfer path 57. .

Next, the imaging element driving unit 10 applies a read pulse to the transfer electrodes V2 and V6, and transfers the charges generated in each photoelectric conversion element of the W photoelectric conversion element group to the vertical charge transfer corresponding to each photoelectric conversion element. Read to path 54. Next, the imaging element driving unit 10 mixes two adjacent charges on the vertical charge transfer path 54 out of the charges read out to the vertical charge transfer path 54, and then converts the mixed charge into the charge storage unit 60. Then, the charge is transferred to the horizontal charge transfer path 57, the charge is transferred to the output amplifier 58 through the horizontal charge transfer path 57, and a signal corresponding to the charge is output therefrom.
When transferring the charge to the horizontal charge transfer path 57, the image sensor driving unit 10 maintains the control pulse φLM2 at the high level and switches only the control pulse φLM1 between the low level and the high level, thereby lowering the electrode 59b. Control is performed so that noise charges accumulated in the charge accumulation unit 60 below the electrode 59a are not transferred to the horizontal charge transfer path 57 while transferring the luminance component charges accumulated in the charge accumulation unit 60 to the horizontal charge transfer path 57. .

  By adopting such driving, noise charges are not transferred onto the horizontal charge transfer path 57, so the signal-to-noise ratio of signals obtained from the RGB photoelectric conversion element group and the signal obtained from the W photoelectric conversion element group It is possible to prevent the SN ratio from deteriorating.

  In addition, even in the configuration in which the W photoelectric conversion element group illustrated in FIG. 5 is changed to the rgb photoelectric conversion element group, it is possible to prevent the SN ratio from being deteriorated.

The figure which shows schematic structure of the digital camera which is an example of the imaging device for demonstrating 1st embodiment of this invention. FIG. 1 is a schematic plan view showing a configuration example of the solid-state imaging device shown in FIG. The plane schematic diagram which showed one structural example of the solid-state image sensor mounted in the imaging device of 2nd embodiment of this invention. The plane schematic diagram which showed one structural example of the solid-state image sensor mounted in the imaging device of 3rd embodiment of this invention. The plane schematic diagram which shows the structural example of the solid-state image sensor mounted in the imaging device of 4th embodiment of this invention.

Explanation of symbols

5 Solid-State Image Sensor 50 Semiconductor Substrate 51R, 51G, 51B, 51W Photoelectric Conversion Element 55 Charge Reading Unit 54 Vertical Charge Transfer Path 57 Horizontal Charge Transfer Path 58 Output Amplifiers V1-V8 Transfer Electrode

Claims (16)

An image pickup apparatus comprising a large number of photoelectric conversion elements, a charge transfer type solid-state image pickup element that reads and transfers charges generated by the large number of photoelectric conversion elements to a charge transfer path, and outputs a signal corresponding to the transferred charges. There,
The multiple photoelectric conversion elements are composed of a first photoelectric conversion element group and a second photoelectric conversion element group,
The first photoelectric conversion element group is composed of photoelectric conversion elements that detect light of a color component necessary for generating color image data;
A first drive that reads the charge from the first photoelectric conversion element group and outputs a signal corresponding to the charge; and a signal that reads the charge from the second photoelectric conversion element group and outputs the signal according to the charge. When performing the two-field drive that is performed separately from the second drive to be output, in either the first drive or the second drive, out of the charges read to the charge transfer path, the adjacent same color component An imaging apparatus including a driving unit that performs driving to mix and transfer charges on the charge transfer path. The imaging apparatus according to claim 1,
An imaging apparatus in which the second photoelectric conversion element group is configured only by a luminance detection photoelectric conversion element in which a luminance filter having a correlation with a luminance component is provided above the light receiving surface. The imaging apparatus according to claim 2,
In the second driving, when the driving unit performs the two-field driving, among the charges read to the charge transfer path, adjacent charges of the same color component are mixed and transferred on the charge transfer path. apparatus. The imaging device according to claim 2 or 3,
The plurality of photoelectric conversion elements are arranged in a square lattice pattern on a semiconductor substrate,
An imaging apparatus in which the first photoelectric conversion element group and the second photoelectric conversion element group are arranged in a checkered pattern. The imaging device according to claim 2 or 3,
The photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are each in the form of a square lattice in the row direction on the semiconductor substrate and in the column direction perpendicular thereto. Are arranged in
An imaging apparatus in which the first photoelectric conversion element group and the second photoelectric conversion element group are arranged so as to be shifted in the row direction and the column direction by a half of the arrangement pitch of the photoelectric conversion elements. The imaging apparatus according to claim 1,
The second photoelectric conversion element group is composed of photoelectric conversion elements that detect light of a color component necessary for generating color image data,
The photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are each in the form of a square lattice in the row direction on the semiconductor substrate and in the column direction perpendicular thereto. Are arranged in
An arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group and an arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group Are the same,
An imaging apparatus in which the first photoelectric conversion element group and the second photoelectric conversion element group are arranged so as to be shifted in the row direction and the column direction by a half of the arrangement pitch of the photoelectric conversion elements. The imaging device according to claim 5 or 6,
The charge transfer path of the solid-state imaging device consists of a vertical charge transfer path and a horizontal charge transfer path,
The solid-state imaging device is provided between the vertical charge transfer path and the horizontal charge transfer path, and temporarily stores the charge transferred through the vertical charge transfer path, and the charge storage An electrode for applying a voltage to the part,
The electrode above the charge storage portion between the vertical charge transfer path and the horizontal charge transfer path from which charges from the first photoelectric conversion element group are read, and from the second photoelectric conversion element group A voltage can be applied independently to each of the electrodes above the charge storage section between the vertical charge transfer path from which charges are read and the horizontal charge transfer path,
The vertical charge from which charges are read from a photoelectric conversion element group that does not need to read the signal when driving to read a signal from only one of the first photoelectric conversion element group and the second photoelectric conversion element group An imaging apparatus comprising control means for controlling the voltage of the electrode so as not to transfer the charge from the transfer path to the horizontal charge transfer path. The imaging device according to any one of claims 1 to 7,
An imaging apparatus in which a color filter array provided above the photoelectric conversion elements constituting the first photoelectric conversion element group is a Bayer array. A method of driving a charge transfer type solid-state imaging device comprising a large number of photoelectric conversion elements, reading out and transferring charges generated by the large number of photoelectric conversion elements to a charge transfer path, and outputting a signal corresponding to the transferred charges. There,
The multiple photoelectric conversion elements are composed of a first photoelectric conversion element group and a second photoelectric conversion element group,
The first photoelectric conversion element group is composed of photoelectric conversion elements that detect light of a color component necessary for generating color image data;
A first drive that reads the charge from the first photoelectric conversion element group and outputs a signal corresponding to the charge; and a signal that reads the charge from the second photoelectric conversion element group and outputs the signal according to the charge. When performing the two-field drive that is performed separately from the second drive to be output, in either the first drive or the second drive, out of the charges read to the charge transfer path, the adjacent same color component A method for driving a solid-state imaging device, wherein charges are mixed and transferred on the charge transfer path. A method for driving a solid-state imaging device according to claim 9,
A method for driving a solid-state imaging device, wherein the second photoelectric conversion element group is configured only by a luminance detection photoelectric conversion element in which a luminance filter having a correlation with a luminance component is provided above the light receiving surface. A method for driving a solid-state imaging device according to claim 10,
When performing the two-field driving, in the second driving, the solid-state imaging device driving method for mixing and transferring adjacent charges of the same color component among the charges read out to the charge transfer path on the charge transfer path . A method for driving a solid-state imaging device according to claim 10 or 11,
The plurality of photoelectric conversion elements are arranged in a square lattice pattern on a semiconductor substrate,
A method for driving a solid-state imaging device, wherein the first photoelectric conversion element group and the second photoelectric conversion element group are arranged in a checkered pattern. A method for driving a solid-state imaging device according to claim 10 or 11,
The photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are each in the form of a square lattice in the row direction on the semiconductor substrate and in the column direction perpendicular thereto. Are arranged in
Driving of a solid-state imaging device in which the first photoelectric conversion element group and the second photoelectric conversion element group are arranged to be shifted in the row direction and the column direction by 1/2 of the arrangement pitch of the photoelectric conversion elements Method. A method for driving a solid-state imaging device according to claim 9,
The second photoelectric conversion element group is composed of photoelectric conversion elements that detect light of a color component necessary for generating color image data,
The photoelectric conversion elements included in the first photoelectric conversion element group and the photoelectric conversion elements included in the second photoelectric conversion element group are each in the form of a square lattice in the row direction on the semiconductor substrate and in the column direction perpendicular thereto. Are arranged in
An arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group and an arrangement of color filters provided above the photoelectric conversion elements constituting the first photoelectric conversion element group Are the same,
Driving of a solid-state imaging device in which the first photoelectric conversion element group and the second photoelectric conversion element group are arranged to be shifted in the row direction and the column direction by 1/2 of the arrangement pitch of the photoelectric conversion elements Method. The solid-state imaging device driving method according to claim 13 or 14,
The charge transfer path of the solid-state imaging device consists of a vertical charge transfer path and a horizontal charge transfer path,
The solid-state imaging device is provided between the vertical charge transfer path and the horizontal charge transfer path, and temporarily stores the charge transferred through the vertical charge transfer path, and the charge storage An electrode for applying a voltage to the part,
The electrode above the charge storage portion between the vertical charge transfer path and the horizontal charge transfer path from which charges from the first photoelectric conversion element group are read, and from the second photoelectric conversion element group A voltage can be applied independently to each of the electrodes above the charge storage section between the vertical charge transfer path from which charges are read and the horizontal charge transfer path,
When the drive for reading a signal from only one of the first photoelectric conversion element group and the second photoelectric conversion element group is executed, the charge is read from the photoelectric conversion element group that does not need to read the signal. A method for driving a solid-state imaging device, wherein the voltage of the electrode is controlled so that the charge from the charge transfer path is not transferred to the horizontal charge transfer path. It is a drive method of the solid-state image sensing device according to any one of claims 9 to 15,
A method for driving a solid-state imaging device, wherein a color filter array provided above the photoelectric conversion elements constituting the first photoelectric conversion element group is a Bayer array.

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