JP2009016972A - Solid state image sensor and electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a pixel mixing function and to easily execute setting and changes in design of a group of pixels to be mixed. <P>SOLUTION: An effective pixel area of a solid state image sensor is divided into pixel blocks 40 which are arranged like a matrix. Each pixel block 40 is composed of a plurality of pixels 20 arrayed to one column in a vertical direction. Each pixel 20 includes a photodiode 51, a floating diffusion 54, a transfer transistor 55, a pixel amplifier 58, a reset switch 59, and a selection transistor 60. Further, each pixel 20 has a first switch 61 arranged between a first end portion (a) of the reset switch 59 and a power supply part Vdd. In each pixel block 40, the first end portions (a) of respective pixels 20 in the pixel block 40 are directly electrically connected to each other by a pixel mixing connection wire 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device and an electronic camera using the same.

  An electronic camera such as a video camera or an electronic still camera has a CCD solid-state imaging device and an amplification solid-state imaging device. In these solid-state imaging devices, a plurality of pixels having photoelectric conversion units are arranged in a matrix, and signal charges are generated in the photoelectric conversion units of the respective pixels.

  In the amplification type solid-state imaging device, signal charges generated and accumulated in the photoelectric conversion unit of the pixel are guided to an amplification unit provided in the pixel, and a signal amplified by the amplification unit is output from the pixel. In general, an amplification type solid-state imaging device is configured such that each pixel has a photoelectric conversion unit that generates and accumulates signal charges corresponding to incident light, and a floating diffusion that receives the signal charges and converts the signal charges into a voltage. A voltage conversion unit, an amplification unit that outputs a signal corresponding to the potential of the charge voltage conversion unit, a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge voltage conversion unit, and a potential of the charge voltage conversion unit A reset unit for resetting to a predetermined reset potential is provided. The signal reading operation is performed by driving each pixel by a peripheral circuit such as a vertical scanning circuit and a horizontal scanning circuit arranged around the pixel region.

  In an electronic camera employing such an amplification type solid-state imaging device, automatic exposure (AE: Auto Exposure) has been performed. In automatic exposure technology, the shutter time and aperture are determined from the output of the solid-state image sensor in a bright environment such as daytime, and pre-flash is performed before the main flash in a dark environment such as nighttime. There is automatic light control that determines the light emission amount, the exposure time, and the shutter speed during the main light emission from the output of the solid-state imaging device.

  Patent Document 1 below discloses that photometric information for automatic exposure is obtained from the solid-state image sensor itself during pre-flash emission of the strobe without providing a photometric sensor for automatic exposure separately from the solid-state image sensor. Yes. Specifically, Patent Document 1 discloses first and second imaging control devices. Each of these first and second imaging control devices is mounted in a solid-state imaging device including at least one strobe for illuminating the subject and a solid-state imaging device having a plurality of pixels arranged in a two-dimensional matrix. And an imaging control device that controls the strobe and the solid-state imaging device. The first and second imaging control devices further include a strobe light emission control circuit that controls the strobe and a sensor drive circuit that controls charge accumulation and charge readout of the solid-state imaging device. The strobe light emission control circuit controls the strobe so that pre-light emission is performed before the main light emission of the strobe light.

  In the first imaging control device, the sensor driving circuit is configured to read the charge accumulated in the plurality of pixels during the pre-flash of the strobe so as to be mixed and read for each predetermined number of pixels. Control the element. According to the first imaging control device, by using the pixel mixing function, it is possible to detect an accurate light amount at the time of pre-emission before strobe emission.

On the other hand, in the second imaging control device, the sensor driving circuit reads the solid-state imaging device so as to read out the charges accumulated in the plurality of pixels during the pre-flash of the strobe for every predetermined number of rows. Control. According to the second image pickup control apparatus, an accurate light amount can be detected during pre-emission before strobe emission by using the line thinning function.
Japanese Patent Laying-Open No. 2005-347928

  In the second imaging control device, since the charges accumulated in the plurality of pixels are read out every predetermined number of rows, the information of the rows that are not read out and are not read out is lost at all. A dead zone occurs in the pixel area. On the other hand, the first imaging control apparatus is preferable because charges accumulated in a plurality of pixels are mixed and read for each predetermined number of pixels, and thus such information loss is avoided.

  However, in Patent Document 1, regarding the pixel mixing function, a sensor driving circuit that controls charge accumulation and charge readout of a solid-state imaging device mixes and reads out charges accumulated in a plurality of pixels for each predetermined number of pixels. As described above, the control of the solid-state imaging device is merely described, and the Patent Document 1 does not disclose a specific configuration of the solid-state imaging device or a specific configuration of the sensor driving circuit at all. There is no indication to suggest. The description in Patent Document 1 only suggests that the pixel mixing function is realized by performing read control of the solid-state imaging device itself by a method different from normal read.

  Then, if it is a normal person skilled in the art, paying attention to the reading control of a solid-state image sensor from the above-mentioned description of Patent Document 1, by devising a sensor drive circuit for driving the solid-state image sensor and a peripheral circuit in the solid-state image sensor, An attempt is made to realize the pixel mixing function by devising a signal readout control method.

  However, in this case, setting or changing at the time of designing a group of pixels to be mixed becomes difficult or complicated.

  In addition, although the said patent document 1 discloses only the point which uses a pixel mixing function for the automatic light control regarding the pre light emission of strobe, as a result of the inventor's research, the pixel mixing function is not limited to automatic light control. It is also useful for performing exposure, displaying moving images such as monitor images or still images on a display unit such as a liquid crystal panel mounted on the electronic camera, and recording moving images. found. For example, when displaying an image such as a monitor image on a display unit having a smaller number of display pixels than the number of pixels of a solid-state image sensor, if simple thinning is not performed without pixel mixing, information on the thinned portion Only images lacking can be displayed. In addition, when recording a moving image of a predetermined standard with a smaller number of pixels compared to the number of pixels of the solid-state image sensor to the recording unit, if simple decimation is performed without pixel mixing, information on the decimation location Only images lacking can be recorded. It is preferable to use a pixel mixing function for such image display and moving image recording because such information loss can be avoided.

  The present invention has been made in view of such circumstances, and can realize a pixel mixing function, and can easily perform setting and changing at the time of designing a group of pixels to be mixed. An object is to provide an element and an electronic camera using the element.

  In order to solve the above problems, the solid-state imaging device according to the first aspect of the present invention includes a photoelectric conversion unit that generates and accumulates signal charges according to incident light, and receives the signal charges and converts the signal charges into a voltage. A charge voltage converter, an amplifier that outputs a signal corresponding to the potential of the charge voltage converter, a charge transfer unit that transfers charges from the photoelectric converter to the charge voltage converter, and a potential of the charge voltage converter A solid-state imaging device having a plurality of pixels having reset switches for resetting to a predetermined reset potential supplied from a power supply unit, and when the signal charges of two or more of the plurality of pixels are mixed The first ends of the reset switches of the two or more pixels opposite to the charge / voltage conversion unit are electrically connected to each other and are not electrically disconnected from the power supply unit. As it may be in a state, in which the configuration.

  A solid-state imaging device according to a second aspect of the present invention is the solid-state imaging device according to the first aspect, wherein the plurality of pixels are divided into a plurality of groups, and a color filter having a different color is provided for each group. A pixel is a pixel provided with a color filter of the same color.

  A solid-state imaging device according to a third aspect of the present invention includes a photoelectric conversion unit that generates and accumulates signal charges according to incident light, a charge-voltage conversion unit that receives the signal charges and converts the signal charges into a voltage, the charge An amplifying unit that outputs a signal corresponding to the potential of the voltage conversion unit, a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge voltage conversion unit, and a potential of the charge voltage conversion unit are supplied from a power supply unit A solid-state imaging device having a plurality of pixels each having a reset switch for resetting to a predetermined reset potential, (i) the charge-voltage conversion unit in the reset switch of two or more pixels of the plurality of pixels; Are respectively provided between the first end on the opposite side and the power supply unit, and (ii) the first end of the reset switch of the two or more pixels is Each other, second Those which are electrically connected through a not or second switch passing through the switch.

  A solid-state imaging device according to a fourth aspect of the present invention includes a photoelectric conversion unit that generates and accumulates signal charges according to incident light, a charge-voltage conversion unit that receives the signal charges and converts the signal charges into a voltage, the charge An amplifying unit that outputs a signal corresponding to the potential of the voltage conversion unit, a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge voltage conversion unit, and a potential of the charge voltage conversion unit are supplied from a power supply unit A solid-state imaging device having a plurality of pixels each having a reset switch for resetting to a predetermined reset potential, (i) the resetting of one or more pixels of two or more pixels of the plurality of pixels A first switch is provided between the first end of the switch opposite to the charge-voltage converter and the power supply, and (ii) the remaining pixels of the two or more pixels The reset switch (Iii) the first ends of the reset switches of the two or more pixels are connected to each other by a second switch. It is electrically connected without going through or via the second switch.

  A solid-state imaging device according to a fifth aspect of the present invention includes a photoelectric conversion unit that generates and accumulates signal charges according to incident light, a charge-voltage conversion unit that receives the signal charges and converts the signal charges into a voltage, the charge An amplifying unit that outputs a signal corresponding to the potential of the voltage conversion unit, a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge voltage conversion unit, and a potential of the charge voltage conversion unit are supplied from a power supply unit A solid-state imaging device having a plurality of pixels each having a reset switch for resetting to a predetermined reset potential, (i) the charge-voltage conversion unit in the reset switch of two or more pixels of the plurality of pixels; Are respectively provided between the first end on the opposite side and the power supply unit, and (ii) at the first end of the reset switch of the two or more pixels, respectively. 1 The first end of the second switch is electrically connected, and (iii) the second end of each second switch is the reset to which the second switch is electrically connected. The second switch is electrically connected to a second end of the second switch that is electrically connected to the reset switch different from the switch.

  A solid-state imaging device according to a sixth aspect of the present invention includes a photoelectric conversion unit that generates and accumulates signal charges according to incident light, a charge-voltage conversion unit that receives the signal charges and converts the signal charges into a voltage, the charge An amplifying unit that outputs a signal corresponding to the potential of the voltage conversion unit, a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge voltage conversion unit, and a potential of the charge voltage conversion unit are supplied from a power supply unit A solid-state imaging device having a plurality of pixels each having a reset switch for resetting to a predetermined reset potential, (i) the resetting of one or more pixels of two or more pixels of the plurality of pixels A first switch is provided between the first end of the switch opposite to the charge-voltage converter and the power supply, and (ii) the remaining pixels of the two or more pixels The reset switch (Iii) one or more first ends of the reset switches of the two or more pixels are not electrically connected to the power supply unit, respectively. A first end of each of the two switches is electrically connected; and (iv) a second end of each of the second switches is the reset switch to which the second switch is electrically connected. The second switch is electrically connected to a second end of the second switch that is electrically connected to the different reset switch.

  A solid-state imaging device according to a seventh aspect of the present invention is the solid-state imaging device according to the fifth or sixth aspect, wherein the second switch is provided in at least one pixel of the two or more pixels and the reset switch of the pixel. A first group of pixels having a reset switch electrically connected thereto, and at least one other of the two or more pixels and the second switch to the reset switch of the pixel. With respect to the second group of pixels having a reset switch electrically connected via a switch, at least one pixel belonging to the first group does not belong to the second group.

  A solid-state imaging device according to an eighth aspect of the present invention is the solid-state imaging device according to any one of the third to seventh aspects, wherein the plurality of pixels are divided into a plurality of groups, and a color filter of a different color is provided for each group. Among the plurality of pixels, pixels in which the first end of the reset switch is electrically connected to each other without passing through the second switch or through the second switch have the same color. It is a pixel provided with a color filter.

  According to a ninth aspect of the present invention, there is provided an electronic camera comprising: the solid-state imaging device according to any one of the first to eighth aspects; and charges respectively generated in two or more of the plurality of pixels. Control means for controlling the solid-state imaging device so that a signal corresponding to the mixed electric charge is read out.

  According to a tenth aspect of the present invention, in the ninth aspect, the electronic camera performs automatic exposure control based on the signal corresponding to the mixed charge.

  An electronic camera according to an eleventh aspect of the present invention is the electronic camera according to the ninth aspect, wherein the signal corresponding to the mixed electric charge is recorded as moving image information in a recording unit.

  An electronic camera according to a twelfth aspect of the present invention is the electronic camera according to the ninth aspect, wherein the signal corresponding to the mixed charge is used as display data for displaying a moving image or a still image on a display unit. .

  An electronic camera according to a thirteenth aspect of the present invention includes a solid-state imaging device according to any one of the first to eighth aspects, and two or more of the plurality of pixels during pre-light emission before the main light emission of the strobe. Control means for controlling the solid-state imaging device so that signals generated in the pixels are mixed and signals corresponding to the mixed charges are read out, and the signals corresponding to the mixed charges are Based on this, automatic exposure control is performed during the main flash of the strobe.

  According to the present invention, a solid-state imaging device capable of realizing a pixel mixing function and easily setting or changing a group of pixels to be mixed and an electronic camera using the same Can be provided.

  Hereinafter, a solid-state imaging device and an electronic camera using the same according to the present invention will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a schematic block diagram showing an electronic camera 1 according to the first embodiment of the present invention. A photographing lens 2 is attached to the electronic camera 1. The photographing lens 2 is driven by a lens control unit 2a for focus and diaphragm. In the image space of the photographic lens 2, the imaging surface of the solid-state imaging device 3 is arranged.

  The solid-state imaging device 3 is driven by a command from the imaging control unit 4 and outputs a signal. The signal output from the solid-state imaging device 3 is either an image signal or an automatic exposure signal (photometric signal). In any case, the signal is processed through the signal processing unit 5 and the A / D conversion unit 6 and then temporarily stored in the memory 7. The memory 7 is connected to the bus 8. The bus 8 includes a lens control unit 2a, an imaging control unit 4, a microprocessor 9, a focus calculation unit 10, an exposure calculation unit 14, a recording unit 11, an image compression unit 12, an image processing unit 13, a display control unit 15, and strobe light emission. A control unit 17 and the like are also connected. The display control unit 15 displays a monitor image or the like on a liquid crystal display unit (LCD) 16. The strobe light emission control unit 17 controls the light emission of the built-in or external strobe 18. The microprocessor 9 is connected to an operation unit 9a such as a release button. A recording medium 11a is detachably attached to the recording unit 11 described above. In the present embodiment, a focus detection sensor (not shown) is provided in addition to the solid-state image sensor 3, but as is known, the solid-state image sensor 3 can also obtain a focus detection signal. It may be configured. The operation of the electronic camera 1 will be described later with reference to FIG.

  FIG. 2 is a circuit diagram showing a schematic configuration of the solid-state imaging device 3 in FIG. The solid-state imaging device 3 includes a plurality of pixels 20 arranged in a matrix and a peripheral circuit for outputting a signal from the pixels 20. In the figure, only 16 pixels 20 of 4 rows horizontally and 4 rows vertically are shown, but the number of pixels is not limited to this. These pixels 20 output either an image signal or an automatic exposure signal in accordance with peripheral circuit drive signals.

  The peripheral circuit includes a vertical scanning circuit 21, a horizontal scanning circuit 22, driving signal lines 24 and 32 to 35 connected thereto, a vertical signal line 25 for receiving signals from pixels, and a constant current connected to the vertical signal line 25. A source 26, a correlated double sampling circuit (CDS) 27, a horizontal signal line 28 for receiving a signal output from the correlated double sampling circuit 27, an output amplifier 29, and the like. In FIG. 2, illustration of a pixel mixing connection wiring 36 to be described later is omitted.

  The vertical scanning circuit 21 and the horizontal scanning circuit 22 output drive signals based on a command from the imaging control unit 4 of the electronic camera 1. Each pixel 20 is driven by receiving drive signals φDIV, φRES, φTX, and φSEL, which will be described later, output from the vertical scanning circuit 21 from the drive signal lines 32 to 35, and receives an image signal or an automatic exposure signal as the vertical signal line 25. Output to.

  The signal output from the pixel 20 is subjected to predetermined noise removal by the correlated double sampling circuit 27. Then, a signal is output to the outside through the horizontal signal line 28 and the output amplifier 29 by the drive signal of the horizontal scanning circuit 22.

  FIG. 3 is a schematic plan view schematically showing the solid-state imaging device 3 (particularly, its effective pixel region 31) in FIG. In the present embodiment, as shown in FIG. 3, the effective pixel region 31 of the solid-state imaging device 3 is divided into pixel blocks 40 arranged in a matrix. As shown in FIGS. 4 and 5, each pixel block 40 includes a plurality (A) of pixels 20 arranged in one column in the vertical direction (column direction).

  FIG. 4 is a circuit diagram showing the pixel block 40. In FIG. 4, the (n + A) -th row of two pixel blocks 40 composed of A pixels 20 arranged from the n-th row to the (n + A−1) -th row and the two pixel blocks 40 adjacent thereto. Pixel 20 is shown. In FIG. 4, the connection state of the drive wirings 32 to 35 is not clearly shown for convenience of drawing, but they are connected in common to each pixel row, and the same drive signal φDIV is connected to the drive wirings 32 to 35 in the same row. , ΦRES, φTX, and φSEL are supplied.

  In the present embodiment, all the pixels 20 have the same circuit configuration. As shown in FIG. 4, each pixel 20 includes a photodiode 51 as a photoelectric conversion unit that generates and accumulates signal charges according to incident light, and the signal charges, as in a general CMOS solid-state imaging device. A floating diffusion (FD) 54 that receives and converts the signal charges into a voltage, a transfer transistor 55 that transfers charges from the photodiode 51 to the FD 54, and a pixel amplifier 58 as an amplifying unit that outputs a signal corresponding to the potential of the FD 54. A reset switch (in this embodiment, a reset transistor) 59 that resets the potential of the FD 54 to a predetermined reset potential supplied from the power supply unit Vdd, and a selection switch that outputs a signal of the pixel amplifier 58 from the pixel. And a selection transistor 60. The second end b of the reset switch 59 is connected to the gate of the pixel amplifier 58, one end of the FD 54 and the transfer transistor 55.

  In a general CMOS type solid-state imaging device, the first end a of the reset switch 59 opposite to the FD 54 is directly connected to the power supply Vdd. On the other hand, in the present embodiment, each pixel 20 includes a first switch (a transistor in the present embodiment) 61 provided between the first end a of the reset switch 59 and the power supply unit Vdd. have. Further, in the present embodiment, unlike a general CMOS type solid-state imaging device, for each pixel block 40, the first end portions a of the A pixels 20 in the pixel block 40 are mutually connected to the pixels. They are directly electrically connected by the mixing connection wiring 36. FIG. 5 is an abstraction of the circuit diagram shown in FIG. 4 focusing on the connection relationship by the pixel mixing connection wiring 36.

  In the present embodiment, the transistors 55 and 58 to 61 of each pixel 20 are all nMOS transistors.

  The gates of the transfer transistors 55 of the respective pixels 20 are commonly connected to the respective pixel rows, and a drive signal φTX is supplied from the vertical scanning circuit 21 via the drive wiring 34. The gates of the selection transistors 60 of the respective pixels 20 are commonly connected to the respective pixel rows, and a drive signal φSEL is supplied from the vertical scanning circuit 21 via the drive wiring 35. The gate of the reset switch 59 of each pixel is connected in common to each pixel row, and a drive signal φRES is supplied from the vertical scanning circuit 21 via the drive wiring 33. The gates of the first switches 61 of the respective pixels 20 are commonly connected to the respective pixel rows, and a drive signal φDIV is supplied from the vertical scanning circuit 21 via the drive wiring 32.

  The photodiode 51 generates a signal charge according to the amount of incident light (subject light). The transfer transistor 55 is turned on during the high level period of the transfer pulse (drive signal) φTX, and transfers the signal charge accumulated in the photodiode 51 to the FD 54. The reset switch 59 is turned on during a high level period of the reset pulse (control signal) φRES, and if the drive signal φDIV is set to a high level and the first switch 61 is turned on, the potential of the FD 54 is changed from the power supply unit Vdd. Reset to the supplied reset potential.

  In a non-mixing / all-pixel reading mode in which signal charges generated from all the pixels 20 are read out without being mixed with each other as in a general CMOS type solid-state imaging device, transfer is performed from the photodiode 51 of each pixel 20. The signal charges transferred to the FD 54 by the transistor 55 are not mixed with the signal charges of the other pixels 20 because the reset switch 59 is kept off until the reading of the signal charges is completed.

  On the other hand, in the mixed / decimated scan readout mode in which the signal charges generated in the pixels 20 in the same pixel block 40 are mixed with each other and read by thinning scanning, the signal charges are transferred from the photodiode 51 of each pixel 20 to the FD 54 by the transfer transistor 55. The reset charge 59 of the incoming signal charge is turned on at least before the signal charge is read (at this time, the first switch 32 is turned off so that the signal charge is not reset). Thus, the FDs 54 of the A pixels 20 in the same pixel block 40 are connected in common, and the signal charges in the FDs 54 in the same pixel block 40 are mixed and averaged. In this mixed / decimated scanning readout mode, signal charges are read out by thinning scanning after such pixel mixing.

  The pixel amplifier 58 of each pixel 20 has a drain connected to the power supply unit Vdd, a gate connected to the FD 54, a source connected to the drain of the selection transistor 60, and a force follower circuit using the constant current source 26 as a load. Is configured. The pixel amplifier 58 outputs a read current to the vertical signal line 25 via the selection transistor 60 according to the voltage value of the FD 54. The selection transistor 60 is turned on during a high level period of the selection pulse (drive signal) φSEL, and connects the source of the pixel amplifier 58 to the vertical signal line 25.

  In the present embodiment, each pixel 20 is not provided with a color filter, and the solid-state imaging device 3 is configured as a monochrome imaging device.

  FIG. 6 is a timing chart showing the operation of the solid-state imaging device 3 in FIG.

  In the present embodiment, in the mixing / decimation scanning readout mode, a mechanical shutter (not shown) is opened for a predetermined exposure period and charges are accumulated in the photodiodes 51 of the respective pixels 20. Rows are sequentially selected in batches for each pixel block, and the same operation is sequentially performed on the rows of the pixel blocks 40. In FIG. 6, the pixel block 40 from the nth row to the (n + A-1) th row is selected, and the pixel block 40 from the next (n + A) th row to the (n + 2A-1) th row is selected. The operation when it is done is shown. In FIG. 6, only the driving signals φDIV, φRES, φTX, and φSEL of some rows are shown, but in this example, the driving signals φDIV, φRES, φTX, and φSEL of the pixels in each row in the same pixel block 40 are the same. The

  The period T1 includes a horizontal scanning period of the pixel block 40 from the (n−A) th row to the (n−1) th row and each pixel 40 of the pixel block 40 from the nth row to the (n + A−1) th row. And also corresponds to a period T3 which will be described later. In the period T1, the reset pulse φRES and the pulse φDIV from the n-th row to the (n + A-1) -th row are set to the high level, and other control signals φSEL and φTX in the rows are set to the low level. The gate voltage of the pixel amplifier 58 (the potential of the FD 54) is reset to the reset potential.

  Next, in the period T2, the vertical scanning circuit 21 selects the pixel blocks 40 from the nth row to the (n + A-1) th row, the selection pulse φSEL of those rows changes to high level, and φDIV becomes low level. To change. As a result, the selection transistors 60 from the n-th row to the (n + A-1) -th row are turned on, and the first switches 61 in those rows are turned off. In the mixed / thinning scanning readout mode, the reset pulse φRES from the n-th row to the (n + A−1) -th row is kept at the high level in the period T2, as well as the other periods, and the reset switch 59 is turned on. Maintained. In the period T2, the source of the pixel amplifier 58 from the nth row to the (n + A-1) th row is connected to the vertical output line 25 by turning on the selection transistors 60 from the nth row to the (n + A-1) th row. The The pixel amplifiers 58 from the nth row to the (n + A−1) th row operate as a source follower circuit by the constant current source 26.

  Between the start time of the period T2 and the start time of the period T11, the dark level of the pixel block 40 from the nth row to the (n + A-1) th row (from the nth row corresponding to the reset state of the FD 54) -1) signals output from the pixel amplifier 58 up to the row) are clamped (saved) from the pixel amplifier 58 to the CDS circuit 27 via the vertical signal line 25. At this time, the gates of the pixel amplifiers 58 in each pixel block 40 from the nth row to the (n + A-1) th row are electrically connected to each other via the reset switch 59 for each pixel block 40. Each pixel block 40 has exactly the same potential. In this example, in the period T2, high level φSEL is input to all the selection transistors 60 from the n-th row to the (n + A−1) -th row, and is turned on. Needless to say, a high level φSEL may be input to the row selection transistor 60.

  In this example, when the pixel signals are mixed, the dark level is acquired in order to perform correlated double sampling. However, if the correlated double sampling is not performed, it is not necessary to acquire the dark level.

  In period T11, the nth to (n + A-1) th rows from the nth row to the (n + A-1) th row with the φRES and φSEL being at the high level and the φDIV of those rows being at the low level. Until φTX is set to the high level, the transfer transistors 55 in those rows are turned on. As a result, the signal charges accumulated in the photodiodes 51 of the respective pixels 20 from the n-th row to the (n + A-1) -th row pass through the transfer transistor 55 and the FD 54 (the gate of the pixel amplifier 58 of the pixel amplifier 58). ). At this time, the FDs 54 in each pixel block 40 from the n-th row to the (n + A-1) -th row are electrically connected to each other via the reset switch 59 for each pixel block 40. The signal charges accumulated in the photodiode 51 of the pixel 20 are mixed and averaged on the FD 54.

  Then, at the end of the period T11, φTX from the nth row to the (n + A−1) th row is set to low, and the transfer transistors 55 in those rows are turned off.

  The average mixed as described above for each pixel block 40 from the n-th row to the (n + A-1) -th row from the end time of the period T11 to the end time of the period T2 (start time of the period T3). The potential fluctuation due to the converted signal charges is clamped to the CDS circuit 27 from the pixel amplifiers 58 from the nth row to the (n + A−1) th row through the vertical signal line 25. That is, signal reading of the signal charges mixed and averaged for each pixel block from the nth row to the (n + A-1) th row is performed. Then, the CDS circuit 27 obtains a difference signal between this signal relating to the mixed and averaged signal charge and the previous dark level, thereby performing correlated double sampling and mixing data of a predetermined pixel signal. To get.

  Thereafter, at the end of the period T2 (the start time of the period T3), φDIV from the nth row to the (n + A−1) th row is set to the high level, and the first switches 61 of those rows are turned on, The resetting of the FDs 54 in those rows is started, and φSEL from the n-th row to the (n + A-1) -th row is set to a low level, the selection transistors 60 in those rows are turned off, and the pixels in those rows The selection of block 40 is terminated.

  The period T3 is a horizontal scanning period for the pixel block 40 from the nth row to the (n + A-1) th row. The period T3 also serves as a reset period for each pixel 40 of the pixel block 40 from the next (n + A) line to the (n + 2A-1) line. From the next pixel block 40 onward, the same operation as in the case of the pixel block 40 from the nth row to the (n + A-1) th row is repeated. In this way, when signals from all the pixel blocks 40 are read out, the mixing / thinning-out scanning reading mode ends.

  As described above, in the mixing / decimation scanning readout mode, only the thinning scanning is not performed, but the thinning scanning is performed after the pixel mixing is performed for each pixel block 40. Therefore, the vertical scanning time can be shortened to 1 / A at the maximum without generating a dead zone in the effective pixel region 31 of the solid-state imaging device 3 (that is, without missing information).

  FIG. 7 is a timing chart showing the operation of the solid-state imaging device 3 in FIG. 1 in the unmixed / all-pixel readout mode.

  In the present embodiment, in the non-mixing / all-pixel readout mode, a mechanical shutter (not shown) is opened for a predetermined exposure period and charges are accumulated in the photodiodes 51 of the pixels 20, and then each pixel row is changed. The pixels are sequentially selected, and the same operation is sequentially performed for each pixel row. FIG. 7 mainly shows the operation when the pixel 20 in the nth row is selected and the pixel 20 in the (n + 1) th row is subsequently selected. In this example, in the unmixed / all-pixel readout mode, a general CMOS solid-state imaging device is always in a state where φDIV of all rows is set to a high level and the first switches 61 of all rows are turned on. The same operation is performed.

  The period T21 serves as both a horizontal scanning period for the pixels 20 in the (n-1) th row and a reset period for the pixels 20 in the nth row, and corresponds to a period T23 described later. In the period T21, φRES in the n-th row is set to a high level, and φSEL and φTX in the n-th row are set to a low level, so that the gate voltage (the potential of the FD 54) of the pixel amplifier 58 is reset to a reset potential.

  Next, in the period T22, the pixel 20 in the nth row is selected by the vertical scanning circuit 21, the RES in the nth row changes to a low level, and the reset switch 59 in the nth row is turned off. In period T22, φSEL in the nth row changes to a high level, and the selection transistor 60 in the nth row is turned on. The source of the pixel amplifier 58 in the n-th row is connected to the vertical output line 25 by turning on the selection transistor 60 in the n-th row. The n-th pixel amplifier 58 operates as a source follower circuit by the constant current source 26. At this time, since the reset switch 59 in the n-th row is off, the gate (FD 54) of each pixel amplifier 58 in the n-th row is electrically separated from the gates (FD 54) of other pixel amplifiers 58. .

  Between the start time of the period T22 and the start time of the period T31, the dark level of the pixel 20 in the n-th row (a signal output from the pixel amplifier 58 in the n-th row corresponding to the reset state of the FD 54) Clamped (saved) in the CDS circuit 27 from the amplifier 58 via the vertical signal line 25. At this time, since the gates of the pixel amplifiers 58 of the pixels 20 in the n-th row are electrically separated from the gates of the other pixel amplifiers 58, the gates of the pixel amplifiers 58 of the pixels 20 in the n-th row are independent of each other. The potential is.

  In the period T31, while the φRES up to the n-th row is in the low level and the φSEL is in the high level, the φTX in the n-th row is set to the high level and the transfer transistors 55 in those rows are turned on. Thereby, the signal charge accumulated in the photodiode of each pixel 20 in the n-th row is transferred to the FD 54 (the gate of the pixel amplifier 58) of the pixel 20 via the transfer transistor 55. At this time, since the gate of the pixel amplifier 58 of the pixel 20 in the n-th row is electrically separated from the gates of the other pixel amplifiers 58, the signal charge accumulated in the photodiode 51 of the pixel 20 remains as it is. It is only transferred to the FD 54 of the pixel 20 and is not mixed with signal charges of other pixels 20.

  At the end of the period T31, φTX in the nth row is set to low, and the transfer transistor 55 in the nth row is turned off. Signal charges transferred to the FD 54 of each pixel 20 in the n-th row from the end time of the period T31 to the end time of the period T22 (start time of the period T23) (independent signal charges for each pixel 20) Is clamped by the CDS circuit 27 via the vertical signal line 25 from each pixel 20 in the n-th row. That is, signal reading of independent signal charges of each pixel 20 in the n-th row is performed. Then, the CDS circuit 27 obtains a difference signal between this signal related to this signal charge and the previous dark level, thereby performing correlated double sampling and obtaining the pixel signal of the n-th row pixel 20.

  Thereafter, at the end of the period T22 (the start time of the period T23), the φRES of the nth row is set high, the nth row reset switch 59 is turned on, and the reset of the FD54 of the nth row is started. , ΦSEL in the nth row is set to low, the selection transistor 50 in the nth row is turned off, and the pixel row selection in the nth row is completed.

  The period T23 is a horizontal scanning period for the pixels 20 in the n rows. The period T23 also serves as a reset period for the pixels 20 in the next (n + 1) th row. The same operation as the nth row is repeated after the next (n + 1) th row. In this way, when signals from all the pixel rows are read, the non-mixed / all-pixel reading mode is terminated.

  In the non-mixing / all-pixel reading mode, as described above, after resetting the gate voltage (the potential of the FD 54) of the pixel amplifier 58, the reset switch 59 is turned off to connect the pixel mixing connection wiring 36 and the first switch 61. Is electrically disconnected from the gate side (FD 54 side) of the pixel amplifier 58, and then the signal charge generated in the photodiode 51 is amplified. Therefore, according to the present embodiment, the pixel mixing connection wiring 36 and the first switch 61 added to the general CMOS solid-state imaging device in this embodiment reduce the amplification gain of the pixel 20. There is no adverse effect such as increased noise.

  FIG. 8 is a schematic flowchart showing an example of the operation of the electronic camera 1 according to the present embodiment.

  The photographer determines the operation mode of the electronic camera 1 via the operation unit 9a. The operation modes of the electronic camera 1 according to the present embodiment are roughly classified into a still image shooting mode and a moving image shooting mode. The microprocessor 9 determines which shooting mode has been selected (step S1). If the still image shooting mode is selected, the process proceeds to step S2. If the moving image shooting mode is selected, the process proceeds to step S21.

  First, the operation after step S2 when the still image shooting mode is selected will be described. In step S <b> 2, the microprocessor 9 gives a command to the solid-state imaging device 3 via the imaging control unit 4 so as to realize the above-described mixing / decimation scanning readout mode. As a result, the above-described mixing / decimation scanning readout mode is realized, and an image signal read out in the mode is output from the solid-state imaging device 3, and the signal passes through the signal processing unit 5 and the A / D converter 6. Data is once stored in the memory 7 (step S3). In the above-described mixed / thinning scanning readout mode, thinning scanning is performed as described above, so that image data can be acquired at high speed.

  Thereafter, the exposure calculation unit 14 calculates an optimum exposure amount based on the image data (that is, photometry data for automatic exposure) obtained in step S3. The lens control unit 2a adjusts the aperture of the photographic lens 2 so that the aperture corresponds to the exposure amount. Further, the imaging control unit 4 sets a shutter time corresponding to the exposure amount obtained by the exposure calculation unit 14. Thus, automatic exposure control (AE) is realized (step S4).

  The focus calculation unit calculates the defocus amount based on a signal from a focus detection sensor (not shown) provided separately from the solid-state image sensor 3 (step S5). The lens control unit 2a drives the photographing lens 2 according to the defocus amount to focus the photographing lens 2 on the subject. Thus, automatic focus control (AF) is realized (step S5).

  Next, the display control unit 15 displays the image data obtained in step S3 on the liquid crystal display unit (LCD) 16 as a monitor image (step S6).

  Thereafter, the photographer presses the release button of the operation unit 9a at a desired timing while confirming the image displayed on the LCD 16. The microprocessor 9 monitors whether or not the release button has been pressed (step S7). When the release button has not been pressed, the operations of steps S3 to S6 are repeated at regular time intervals.

  When the release button is pressed (in the case of YES at step S7), image data is again obtained and stored in the memory 7 once again in the mixing / thinning scanning readout mode (step S8), as in step S3. Based on this image data, an AE operation (step S9) similar to step S4 is performed. Further, the AF operation (step S10) similar to step S5 is performed.

  Next, the microprocessor 9 gives a command to the solid-state imaging device 3 through the imaging control unit 4 so as to realize the above-described non-mixing / all-pixel readout mode as the main imaging (step S11). As a result, the unmixed / all-pixel readout mode described above is realized, and an image signal read out in the mode is output from the solid-state imaging device 3, and the signal passes through the signal processing unit 5 and the A / D converter 6. The image data is temporarily stored in the memory 7 (step S12).

  Thereafter, the microprocessor 9 performs a desired process in the image processing unit 13 or the image compression unit 12 as necessary based on a command from the operation unit 9a, and causes the recording unit 11 to output a processed signal to the recording medium 11a. (Step S13). As a result, the series of operations is completed.

  Next, operations after step S21 when the moving image shooting mode is selected will be described. The operations in steps S21 to S25 are the same as those in steps S2 to S6.

  Thereafter, the photographer presses the release button of the operation unit 9a at a desired timing in order to start moving image shooting while checking the image displayed on the LCD 16. The microprocessor 9 monitors whether or not the release button has been pressed (step S26). When the release button has not been pressed, the operations of steps S21 to S25 are repeated at regular time intervals.

  When the release button is pressed (in the case of YES at step S26), image data is again obtained and stored in the memory 7 once again in the mixing / thinning scanning readout mode (step S27), as in steps S3 and S22. Thereafter, the AE operation (step S28) similar to steps S4 and S23 is performed based on the latest image data obtained in the mixing / thinning scanning readout mode. Further, an AF operation (step S29) similar to steps S5 and S24 is performed.

  Subsequently, again in the same manner as steps S3, S22, and S27, image data is obtained by the mixing / thinning scanning read mode and temporarily stored in the memory 7 (step S30), and the recording unit 11 records this image as a moving image as a recording medium. 11a is recorded (step S31). Thereafter, the microprocessor 9 determines whether or not an instruction to end moving image shooting has been obtained from the operation unit 9a (step S32). If there is no instruction, the process returns to step S28. finish.

  In the operation example described above, in the AE operation of steps S4, S9, S23, and S28, an image (photometric data) from the solid-state image sensor 3 in the mixing / thinning-scanning readout mode is used, and the solid-state image sensor 3 is the AE sensor. Since it fulfills its function, it is not necessary to attach individual AE sensors or optical components for these sensors, and the electronic camera 1 can be miniaturized. As described above, the solid-state imaging device 3 used in the present embodiment can perform high-speed reading by thinning scanning without generating a dead zone. Therefore, when performing an AE operation using the solid-state imaging device. Also useful.

  In addition, since the solid-state imaging device 3 used in the present embodiment can perform thinning scanning without generating a dead zone, accurate and high-speed image acquisition is possible. Therefore, in the above-described operation example, the image data from the solid-state imaging device 3 in the mixing / decimation scanning readout mode is used as display data on the LCD 16 in steps S6 and S25 and image data for moving image recording in step S31. Therefore, it is preferable. In particular, since the electronic camera 1 according to the present embodiment combines still image shooting and moving image shooting, in general, when shooting a still image that requires high resolution, shooting is performed without thinning out pixels. The number of pixels A in the vertical direction of the one pixel block 40 (that is, the thinning interval A) is appropriately set so that the thinning scanning can be performed without excess or deficiency in a form suitable for the resolution of the moving image display device at the time of moving image shooting. By setting it, the read operation can be performed at high speed without generating a dead zone.

  In the description of the operation example described above, the AE operation in steps S4, S9, S23, and S28 has been described as determining the shutter time and the aperture from the output of the solid-state imaging device 3 in a bright environment such as daytime. For example, when shooting with strobe light emission in a dark environment such as at night, the strobe light emission control unit 17 causes the strobe light 18 to pre-emit before the main light emission of the strobe light 18. For example, at the time of the pre-flash, the imaging control unit 4 acquires an image in the mixing / decimation scan readout mode in step S8, and in the AE operation in step S9, the exposure calculation unit 14 determines an optimal exposure amount based on the acquired data. Then, the lens control unit 2a adjusts the aperture of the photographing lens 2 so that the aperture according to the exposure amount is obtained, and the imaging control unit 4 sets the shutter time corresponding to the exposure amount obtained by the exposure calculation unit 14. Then, the exposure calculation unit 14 supplies the light control information of the strobe 18 corresponding to the exposure amount to the strobe light emission control unit 17. In step S12, the strobe light emission control unit 17 causes the strobe 18 to perform main light emission so as to be in a light control state according to the light control information, and at the time of the main light emission, an unmixed / all pixel readout mode is realized. An image signal read in the mode is output from the solid-state imaging device 3, and the signal is stored in the memory 7 as image data through the signal processing unit 5 and the A / D converter 6.

  By the way, in this embodiment, as described above, each pixel 20 is not provided with a color filter, and the solid-state imaging device 3 is configured as a monochrome imaging device. Accordingly, in spite of the pixel 20 in one pixel block 40 in which signal charges are mixed in the mixed / thinning-scanning readout mode, the LCD 16 does not exceed the A pixels 20 arranged in a row in the vertical direction. The problem of color mixing due to the mixing of signal charges of different colors does not occur when displaying on the screen or recording a moving image. However, in the present embodiment, when the color filter according to the Bayer arrangement or the like is provided in each pixel 20 in order to colorize with the configuration of the pixel block 40 as it is, this is caused by mixing of signal charges of different colors. The problem of color mixing occurs. Therefore, when colorization is performed by such a method, data obtained in the mixing / decimation scan readout mode cannot be used as image data, and data for display on the LCD 16 in steps S6 and S25, or step S31. It cannot be used as image data for recording moving images. However, even if the colorization is performed in this way, there is no problem even if the signal charges of different colors are mixed as the automatic exposure data. Therefore, the data obtained in the mixed / thinning scanning readout mode is obtained in steps S4 and S9. , S23, S28 can be used in the AE operation. An example of a solid-state imaging device configured to be used not only as an AE operation but also as image data when colorized will be described later as another embodiment.

  As described above, according to the solid-state imaging device 3 used in the present embodiment, a pixel mixing function is realized without generating a dead zone in the effective pixel region 31 of the solid-state imaging device 3 (that is, The scanning time can be shortened and high-speed reading can be performed without losing information. In the solid-state imaging device 3, a group of pixels 20 to be mixed can be set only by arbitrarily determining the first end a of the reset switch 59 of the pixels 20 connected to each other by the pixel mixing connection wiring 36. Can do. Therefore, setting and changing at the time of designing a group of pixels to be mixed can be performed very easily.

  In the present embodiment, the pixels 20 are blocked (grouped) only in the vertical direction. However, by grouping the pixels 20 in the horizontal direction or a combination of the horizontal and vertical directions in the same manner, Needless to say, the scanning time can be shortened. FIG. 9 shows such a modification of the solid-state imaging device 3 in FIG. FIG. 9 is a circuit diagram showing the pixel block 41 of the solid-state imaging device according to the modification of the solid-state imaging device 3 in FIG. It corresponds to. In the modification shown in FIG. 9, the first ends a of the reset switches 59 of all the pixels 20 of the two pixel blocks 40 adjacent in the horizontal direction in FIG. 5 are electrically connected to each other, thereby The two pixel blocks 40 are integrated into one pixel block 41.

  When data obtained from the solid-state imaging device 3 in the mixing / decimation scanning readout mode is used only as automatic exposure data, the data on the peripheral area in the effective pixel region 31 is not used as automatic exposure data. In such a case, the pixels 20 in the peripheral area need not be made into blocks. Therefore, for the pixel 20 that does not need to be blocked in this way, the first end a of the reset switch 59 of the pixel 20 is mixed with the first end a of the reset switch 59 of the other pixel 20. The first switch 61 may be removed from the pixel 20 and the first end a of the reset switch 59 of the pixel may be directly connected to the power supply unit Vdd without being connected by the connection wiring 36 for use. That is, for the pixel 20 that does not need to be blocked, the pixel structure of a general CMOS solid-state image sensor may be employed as it is.

  [Second Embodiment]

  FIG. 10 is a circuit diagram showing a pixel block 40 of a solid-state imaging device used in an electronic camera according to the second embodiment of the present invention, and corresponds to FIG. 10, elements that are the same as or correspond to those in FIG. 4 are given the same reference numerals, and redundant descriptions thereof are omitted.

  This embodiment differs from the first embodiment in each pixel block 40 except for one pixel 20 (the nth row of pixels 20 in FIG. 10) The only difference is that the first switch 61 is removed from the pixel 20. In the pixel 20 from which the first switch 61 is removed, the first end a of the reset switch 59 of the pixel 20 is not directly connected to the power supply, unlike the pixel structure of a general CMOS type solid-state imaging device. It is not electrically connected to the part Vdd.

  Also in this embodiment, it is possible to drive by the same drive sequence as the drive sequence shown in FIGS. 6 and 7 described in the first embodiment. This embodiment can provide the same advantages as those of the first embodiment.

  If at least one pixel 20 has the first switch 61 in each pixel block 40, the number of the pixels 20 from which the first switch 61 is removed in the pixel block 40 is not limited at all. is not.

  [Third Embodiment]

  FIG. 11 is a circuit diagram showing the pixel block 42 of the solid-state imaging device used in the electronic camera according to the third embodiment of the present invention in an abstract manner, focusing on the connection relationship by the pixel mixing connection wiring 36. Yes, corresponding to FIG. 11, elements that are the same as or correspond to those in FIG. 5 are given the same reference numerals, and redundant descriptions thereof are omitted. This embodiment is different from the first embodiment only in the points described below.

  In this embodiment, the circuit configuration of each pixel 20 is the same as that in the first embodiment, but each pixel 20 has a color filter (not shown) on the light incident side of the photodiode 51. ) Is provided. In the present embodiment, a system using R, G, and B is employed as a combination of color filters, and a Bayer array is employed. However, a stripe arrangement or the like may be employed, or a complementary color system (for example, a system using magenta, green, cyan, and yellow) may be employed. In FIG. 11, R is added to the pixel 20 provided with the red color filter, G is assigned to the pixel 20 provided with the green color filter, and B is assigned to the pixel 20 provided with the blue color filter. is doing. This also applies to each of the later-described colorized embodiments.

  In the present embodiment, the effective pixel region of the solid-state imaging device is divided into pixel blocks 42 arranged in a matrix. Each pixel block 42 includes 6 × 2 pixels 20 as shown in FIG. In the present embodiment, the first end portions a of the reset switches 59 of three pixels 20 of the same color adjacent to every other pixel in the same vertical column are electrically connected to each other by the pixel mixing connection wiring 36. It is connected. As described above, in this embodiment, for each color, the three pixels 20 arranged in the vertical direction every other pixel are grouped as a group capable of mixing signal charges. As can be understood from FIG. 11, the pixel block 42 does not mean a group of pixels that can mix signal charges, but means a repeating unit of a pixel pattern that takes into account the connection state by the pixel mixing connection wiring 36. I'm just doing it.

  Also according to the present embodiment, it is possible to drive by a drive sequence basically similar to the drive sequence shown in FIGS. 6 and 7 described in the first embodiment. Also in this embodiment, the same advantages as those in the first embodiment can be obtained.

  Furthermore, according to the present embodiment, since each pixel 20 is grouped as a group capable of mixing signal charges for each color, signal charges of different colors are mixed even in the mixing / thinning-out scanning readout mode. The data obtained in the mixed / thinning scanning readout mode can be used not only as data for automatic exposure but also as image data.

  [Fourth Embodiment]

  FIG. 12 is a circuit diagram showing an abstraction of the pixel block 43 of the solid-state imaging device used in the electronic camera according to the fourth embodiment of the present invention, focusing on the connection relationship by the pixel mixing connection wiring 36. Yes, corresponding to FIG. In FIG. 12, elements that are the same as or correspond to those in FIG. The present embodiment is different from the first embodiment only in the points described below.

  In this embodiment, the circuit configuration of each pixel 20 is the same as that in the first embodiment, but each pixel 20 has a color according to the Bayer arrangement on the light incident side of the photodiode 51. A filter (not shown) is provided. In the present embodiment, the effective pixel area of the solid-state imaging device is divided into pixel blocks 43 arranged in a matrix. Each pixel block 43 includes 4 × 4 pixels 20 as shown in FIG. In the present embodiment, the first ends a of the reset switches 59 of 2 × 2 pixels 20 of the same color closest to the vertical direction and the horizontal direction are electrically connected to each other by the pixel mixing connection wiring 36. ing. As described above, in this embodiment, 2 × 2 pixels 20 are grouped as a group in which signal charges can be mixed for each color. As can be understood from FIG. 12, the pixel block 43 does not mean a group of pixels that can mix signal charges, but means a repeating unit of a pixel pattern that takes into account the connection state by the pixel mixing connection wiring 36. I'm just doing it.

  Also according to the present embodiment, it is possible to drive by a drive sequence basically similar to the drive sequence shown in FIGS. 6 and 7 described in the first embodiment. Also in this embodiment, the same advantages as those in the first embodiment can be obtained.

  Furthermore, according to the present embodiment, since each pixel 20 is grouped as a group capable of mixing signal charges for each color, signal charges of different colors are mixed even in the mixing / thinning-out scanning readout mode. The data obtained in the mixed / thinning scanning readout mode can be used not only as data for automatic exposure but also as image data.

  [Fifth Embodiment]

  FIG. 13 is a circuit diagram showing a pixel block 44 of a solid-state imaging device used in an electronic camera according to the fifth embodiment of the present invention, and corresponds to FIG. FIG. 14 is an abstraction of the circuit diagram shown in FIG. 13 focusing on the connection relationship by the pixel mixing connection wires 136 and 137, and corresponds to FIG. 13 and 14, the same or corresponding elements as those in FIGS. 4 and 5 are denoted by the same reference numerals, and redundant description thereof is omitted. This embodiment is different from the first embodiment only in the points described below.

  In the present embodiment, each pixel 120 is provided in place of each pixel 20. The pixel 120 is different from the pixel 20 only in that two second switches 81 and 82 are added. In the present embodiment, the second switches 81 and 82 are nMOS transistors. The first end c1 of the second switch 81 and the first end c2 of the second switch 82 are each electrically connected to the first end a of the reset switch 59. Although not shown in the drawing, the gates of the second switches 81 are commonly connected to the respective pixel rows, and the drive signal φJ1 is supplied from the vertical scanning circuit 21 via the drive wiring 181. The gates of the second switches 82 are commonly connected to the respective pixel rows, and the drive signal φJ2 is supplied from the vertical scanning circuit 21 through the drive wiring 182. In the present embodiment, the second switches 81 and 82 have a function of selecting the connection destination of the first end a of the reset switch 59.

  In the present embodiment, the effective pixel area of the solid-state imaging device is divided into pixel blocks 44 arranged in a matrix. As shown in FIG. 13, each pixel block 44 includes four pixels 120 arranged in one column in the vertical direction (column direction). In each pixel block 44, the second ends d 1 of the second switches 81 of the four pixels 120 are directly electrically connected to each other by the pixel mixing connection wiring 136. In each pixel block 44, the second ends d2 of the upper two second switches 82 in FIG. 13 are directly electrically connected to each other by the pixel mixing connection wiring 137. Further, in each block 44, the second ends d2 of the two second switches 82 on the lower side in FIG. 13 are directly electrically connected to each other by the pixel mixing connection wiring 137.

  As can be seen from the above description, for example, in each pixel block 44, the first end a of the reset switch 59 of the first pixel 120 from the upper side in FIG. 13 passes through the two second switches 81. The remaining three pixels 120 are electrically connected to the first end a of the reset switch 59. Further, for example, in each pixel block 44, the first end a of the reset switch 59 of the first pixel 120 from the upper side in FIG. 13 is connected to the second pixel 120 via the two second switches 82. The reset switch 59 is electrically connected to the first end a.

  In the present embodiment, as the mixing / decimation scanning readout mode, four pixels are read by mixing the signal charges of the four pixels 120 to which the second switch 81 is connected to each other via the pixel mixing connection wiring 136 and reading them by the thinning scanning. Mixing / decimating scan readout mode and two-pixel mixing / decimating scan readout in which the signal charges of the two pixels 120 to which the second switch 82 is connected to each other by the pixel mixing connection wiring 137 are mixed and read out by thinning scanning. Both modes can be switched arbitrarily.

  FIG. 15 is a timing chart showing a four-pixel mixing / thinning-out scanning readout mode of the solid-state imaging device according to the present embodiment.

  In the four-pixel mixing / decimation scan readout mode, φJ1 of all rows is always set to high level, the second switches 81 of all rows are turned on, and φJ2 of all rows is set to low level so that all rows The second switch 82 is turned off. In the four-pixel mixing / thinning-out scanning readout mode, operations corresponding to the operations in the periods T1 to T5 in FIG. 6 are performed in the periods T41 to T45 in FIG. As an explanation of the operation in the four-pixel mixing / thinning-out scanning readout mode, the explanation regarding FIG. 6 should be read as A = 4.

  FIG. 16 is a timing chart showing the two-pixel mixing / thinning-out scanning readout mode of the solid-state imaging device according to the present embodiment.

  In the two-pixel mixed / decimated scanning readout mode, φJ1 in all rows is always set to low level and the second switch 81 in all rows is turned off, and φJ2 in all rows is always set to high level. The second switch 82 in the row is turned on. In the two-pixel mixing / thinning-out scanning readout mode, operations corresponding to the operations in the periods T1 to T5 in FIG. 6 are performed in the periods T51 to T55 in FIG. As an explanation of the operation in the two-pixel mixing / thinning-out scanning readout mode, the explanation regarding FIG. 6 should be read as A = 2.

  In the non-mixed / all pixel readout mode, the first implementation is always performed with the first switches 61 of all rows turned on and the second switches 81 and 82 of all rows turned off. In this embodiment, the same operation as described with reference to FIG.

  According to the present embodiment, the same advantages as those of the first embodiment can be obtained, and the group of pixels 120 to be mixed can be changed with respect to the mixing / decimation scanning readout mode. The advantage that a more appropriate mixed pattern can be realized according to the above is also obtained.

  In the present embodiment, the four-pixel mixing / thinning-out scanning readout mode and the two-pixel mixing / thinning-out scanning reading mode are configured to be performed. However, the present invention is not limited to this, and the second switch 81 of each pixel 120 is used. , 82 can be variously changed in the connection pattern of the second end portions d1 and d2 to perform various mixing / thinning scanning readout modes. In the present embodiment, two second switches 81 and 82 are connected to the first end a of the reset switch 59 of one pixel, but three or more second switches are connected to the end a. By connecting these switches, it is possible to increase the selectable types of the mixed / thinning scanning readout mode.

  In each pixel block 44, for example, the second switch 82 of the first pixel 120 from the upper side in FIG. 13 is removed, and the first end of the reset switch 59 of the first pixel 120 from the upper side in FIG. Even if the part a is electrically connected to the second end d2 of the second switch 82 of the second pixel 120, the above-described operation can be realized.

  Further, in each pixel block 44, as described in the second embodiment, even if the first switch 61 is removed from the second pixel 120 and the third pixel 120 from the upper side in FIG. Operation can be realized. In these pixels 120, unlike the pixel structure of a general CMOS type solid-state imaging device, the first end a of the reset switch 59 of the pixel 120 is directly electrically connected to the power supply unit Vdd. Will not be.

  [Sixth Embodiment]

  FIG. 17 is a circuit diagram showing an abstraction of the pixel block 45 of the solid-state image sensor used in the electronic camera according to the sixth embodiment of the present invention, paying attention to the connection relationship by the pixel mixing connection wires 136 and 137. FIG. 14 corresponds to FIG. 17, elements that are the same as or correspond to elements in FIG. 14 are given the same reference numerals, and redundant descriptions thereof are omitted. The present embodiment is different from the fifth embodiment only in the points described below.

  In the present embodiment, the circuit configuration of each pixel 120 is the same as that in the fifth embodiment, but each pixel 120 has a color according to the Bayer arrangement on the light incident side of the photodiode 51. A filter (not shown) is provided. In the present embodiment, a system using R, G, and B is employed as a combination of color filters, and a Bayer array is employed.

  In the present embodiment, the effective pixel area of the solid-state imaging device is divided into pixel blocks 45 arranged in a matrix. Each pixel block 45 includes 8 × 2 pixels 120 as shown in FIG. In each pixel block 45, the second ends d1 and d2 of the second switches 81 and 82 of each pixel 120 are electrically connected for each color by the pixel mixing connection wirings 136 and 137 as shown in FIG. It is connected to the.

  Also according to the present embodiment, it is possible to drive with a drive sequence basically similar to the drive sequence described in the fifth embodiment. Also in this embodiment, the same advantages as those in the fifth embodiment can be obtained.

  Furthermore, according to the present embodiment, since each pixel 120 is grouped as a group capable of mixing signal charges for each color, signal charges of different colors are mixed even in the mixed / thinning-scanning readout mode. The data obtained in the mixed / thinning scanning readout mode can be used not only as data for automatic exposure but also as image data.

  As mentioned above, although each embodiment of this invention and its modification were demonstrated, this invention is not limited to these.

  For example, each of the above embodiments is an example in which the present invention is applied to a solid-state imaging device in which each pixel has a pixel amplifier 58, an FD 54, a selection transistor 60, and a reset switch 59. However, the present invention is not limited to this, and can be applied to, for example, a solid-state imaging device in which a plurality of pixels share a set of pixel amplifier 58, FD 54, selection transistor 60, and reset switch 59. it can.

1 is a schematic block diagram showing an electronic camera 1 according to a first embodiment of the present invention. It is a circuit diagram which shows schematic structure of the solid-state image sensor in FIG. It is a schematic plan view which shows typically the solid-state image sensor in FIG. It is a circuit diagram which shows the pixel block of the solid-state image sensor in FIG. FIG. 5 is a circuit diagram abstractly showing the circuit diagram shown in FIG. 4. 2 is a timing chart illustrating an operation of the solid-state imaging device in FIG. 1 in a mixing / thinning-out scanning readout mode. 2 is a timing chart illustrating an operation of the solid-state imaging device in FIG. 1 in an unmixed / all-pixel readout mode. 3 is a schematic flowchart illustrating an example of an operation of the electronic camera illustrated in FIG. 1. FIG. 2 is a circuit diagram showing an abstract pixel block of a solid-state image sensor according to a modification of the solid-state image sensor in FIG. 1. It is a circuit diagram which shows the pixel block of the solid-state image sensor used with the electronic camera by the 2nd Embodiment of this invention. It is a circuit diagram which abstractly shows the pixel block of the solid-state image sensor used with the electronic camera by the 3rd Embodiment of this invention. It is a circuit diagram which abstractly shows the pixel block of the solid-state image sensor used with the electronic camera by the 4th Embodiment of this invention. It is a circuit diagram which shows the pixel block of the solid-state image sensor used with the electronic camera by the 5th Embodiment of this invention. FIG. 14 is a circuit diagram abstractly showing the circuit diagram shown in FIG. 13. It is a timing chart which shows 4 pixel mixing / thinning-out scanning readout mode of the solid-state image sensor used with the electronic camera by the 5th Embodiment of this invention. It is a timing chart which shows 2 pixel mixing and thinning-out scanning readout mode of the solid-state image sensor used with the electronic camera by the 5th Embodiment of this invention. It is a circuit diagram which abstractly shows the pixel block of the solid-state image sensor used with the electronic camera by the 6th Embodiment of this invention.

Explanation of symbols

51 Photodiode 54 Floating diffusion (FD)
55 transfer transistor 58 pixel amplifier 59 reset switch 60 selection transistor 61 first switch 81, 82 second switch Vdd power supply unit

Claims (13)

A photoelectric conversion unit that generates and accumulates signal charge according to incident light, a charge-voltage conversion unit that receives the signal charge and converts the signal charge into voltage, and an amplifier that outputs a signal according to the potential of the charge-voltage conversion unit A pixel having a reset switch that resets the potential of the charge-voltage conversion unit to a predetermined reset potential supplied from a power supply unit, and a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge-voltage conversion unit A plurality of solid-state imaging devices,
When mixing the signal charges of two or more pixels of the plurality of pixels, the first ends of the reset switches of the two or more pixels opposite to the charge voltage conversion unit are electrically connected to each other. A solid-state image pickup device configured to be connected to each other and to be electrically disconnected from the power supply unit. The plurality of pixels are divided into a plurality of groups, and different color filters are provided for each group,
2. The solid-state imaging device according to claim 1, wherein the two or more pixels are pixels provided with a color filter of the same color. A photoelectric conversion unit that generates and accumulates signal charge according to incident light, a charge-voltage conversion unit that receives the signal charge and converts the signal charge into voltage, and an amplifier that outputs a signal according to the potential of the charge-voltage conversion unit A pixel having a reset switch that resets the potential of the charge-voltage conversion unit to a predetermined reset potential supplied from a power supply unit, and a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge-voltage conversion unit A plurality of solid-state imaging devices,
A first switch is provided between the power supply unit and the first end of the reset switch of the two or more pixels of the plurality of pixels opposite to the charge-voltage conversion unit. ,
Solid-state imaging characterized in that the first ends of the reset switches of the two or more pixels are electrically connected to each other without passing through a second switch or via a second switch element. A photoelectric conversion unit that generates and accumulates signal charge according to incident light, a charge-voltage conversion unit that receives the signal charge and converts the signal charge into voltage, and an amplifier that outputs a signal according to the potential of the charge-voltage conversion unit A pixel having a reset switch that resets the potential of the charge-voltage conversion unit to a predetermined reset potential supplied from a power supply unit, and a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge-voltage conversion unit A plurality of solid-state imaging devices,
Between the first end of the one or more pixels of the plurality of pixels opposite to the charge-voltage conversion unit in the reset switch and the power supply unit, A first switch is provided;
The first end of the reset switch of the remaining pixels of the two or more pixels is not electrically connected to the power supply unit,
Solid-state imaging characterized in that the first ends of the reset switches of the two or more pixels are electrically connected to each other without passing through a second switch or via a second switch element. A photoelectric conversion unit that generates and accumulates signal charge according to incident light, a charge-voltage conversion unit that receives the signal charge and converts the signal charge into voltage, and an amplifier that outputs a signal according to the potential of the charge-voltage conversion unit A pixel having a reset switch that resets the potential of the charge-voltage conversion unit to a predetermined reset potential supplied from a power supply unit, and a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge-voltage conversion unit A plurality of solid-state imaging devices,
A first switch is provided between the power supply unit and the first end of the reset switch of the two or more pixels of the plurality of pixels opposite to the charge-voltage conversion unit. ,
A first end of one or more second switches is electrically connected to each of the first ends of the reset switch of the two or more pixels;
The second end of each second switch has a second end of the second switch electrically connected to the reset switch different from the reset switch to which the second switch is electrically connected. A solid-state imaging device, wherein the solid-state imaging device is electrically connected to an end of the image sensor. A photoelectric conversion unit that generates and accumulates signal charge according to incident light, a charge-voltage conversion unit that receives the signal charge and converts the signal charge into voltage, and an amplifier that outputs a signal according to the potential of the charge-voltage conversion unit A pixel having a reset switch that resets the potential of the charge-voltage conversion unit to a predetermined reset potential supplied from a power supply unit, and a charge transfer unit that transfers charges from the photoelectric conversion unit to the charge-voltage conversion unit A plurality of solid-state imaging devices,
Between the first end of the one or more pixels of the plurality of pixels opposite to the charge-voltage conversion unit in the reset switch and the power supply unit, A first switch is provided;
The first end of the reset switch of the remaining pixels of the two or more pixels is not electrically connected to the power supply unit,
A first end of one or more second switches is electrically connected to each of the first ends of the reset switch of the two or more pixels;
The second end of each second switch has a second end of the second switch electrically connected to the reset switch different from the reset switch to which the second switch is electrically connected. A solid-state imaging device, wherein the solid-state imaging device is electrically connected to an end of the image sensor.   A first group comprising at least one pixel of the two or more pixels and a pixel having a reset switch electrically connected to the reset switch of the pixel via the second switch; and A second group comprising at least one other pixel of the two or more pixels and a pixel having a reset switch electrically connected to the reset switch of the pixel via the second switch; The solid-state imaging device according to claim 5, wherein at least one pixel belonging to the first group does not belong to the second group. The plurality of pixels are divided into a plurality of groups, and different color filters are provided for each group,
Among the plurality of pixels, pixels in which the first end of the reset switch is electrically connected to each other without passing through the second switch or through the second switch have the same color The solid-state imaging device according to claim 3, wherein the pixel is a pixel provided with a filter. A solid-state imaging device according to any one of claims 1 to 8,
Control means for controlling the solid-state imaging device so that charges respectively generated in two or more pixels of the plurality of pixels are mixed and a signal corresponding to the mixed charges is read out;
An electronic camera characterized by comprising:   The electronic camera according to claim 9, wherein automatic exposure control is performed based on the signal corresponding to the mixed charge.   The electronic camera according to claim 9, wherein the signal corresponding to the mixed electric charge is recorded as moving image information in a recording unit.   The electronic camera according to claim 9, wherein the signal corresponding to the mixed electric charge is used as display data for displaying a moving image or a still image on a display unit. A solid-state imaging device according to any one of claims 1 to 8,
The solid-state imaging device so that charges generated in two or more of the plurality of pixels are mixed during pre-emission before the main flash of the strobe and signals corresponding to the mixed charges are read out. Control means for controlling
With
An electronic camera that performs automatic exposure control during the main flash of the strobe based on the signal corresponding to the mixed charge.

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