JP2011188306A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of greatly extending a dynamic range. <P>SOLUTION: A solid-state image sensor 5 has a plurality of pairs of photoelectric conversion elements 51, 52 with different sensitivity. A vertical electric charge transfer path 53a is provided between the pair of photoelectric conversion elements 51 and 52, and the vertical electric charge transfer path 53a between the pair of photoelectric conversion elements 51 and 52 accumulates smear charges at a position corresponding to the pair during an exposure period. A D range extension processing unit 19 generates image data using a first signal corresponding to signal electric charges accumulated in the photoelectric conversion element 51 of the pair during the exposure period, a second signal corresponding to signal electric charges accumulated in the photoelectric conversion element 52 of the pair during the exposure period, and a third signal corresponding to the smear electric charges accumulated at the position of the vertical electric charge transfer path 53a corresponding to the pair during the exposure period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus.

  Patent Document 1 discloses a method for synthesizing a signal corresponding to a smear charge accumulated in a charge transfer path and a signal corresponding to a signal charge read from a photoelectric conversion element as a method of expanding a dynamic range (D range). Has been. However, in recent imaging apparatuses, a wider dynamic range is required, and there is a limit to the expansion of the dynamic range only by the method described in Patent Document 1.

JP 2003-189187 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus capable of greatly expanding the dynamic range.

  The imaging apparatus of the present invention is an imaging apparatus having a solid-state imaging device and a signal processing unit that generates one image data using a plurality of signals read from the solid-state imaging device in a plurality of fields. The solid-state imaging device includes a plurality of photoelectric conversion elements and a charge transfer path that transfers signal charges accumulated in the photoelectric conversion elements, and the plurality of photoelectric conversion elements are arranged in proximity to each other with a difference in sensitivity. A plurality of pairs of a first photoelectric conversion element and a second photoelectric conversion element that output a signal, and the charge transfer between the first photoelectric conversion element and the second photoelectric conversion element of the pair A path is provided, and the charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element of the pair can be driven to accumulate smear charges at a position corresponding to the pair. And the signal processing A first signal corresponding to the signal charge accumulated in the first photoelectric conversion element of the pair, and a second signal corresponding to the signal charge accumulated in the second photoelectric conversion element of the pair The image data is generated using a signal and a third signal corresponding to the smear charge accumulated by the driving at the position of the charge transfer path corresponding to the pair.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which can extend a dynamic range significantly can be provided.

The figure which shows schematic structure of the imaging device for describing one Embodiment of this invention FIG. 1 is a schematic plan view showing a schematic configuration of a solid-state imaging device 5 in the digital camera shown in FIG. Enlarged view of range III in the solid-state imaging device shown in FIG. The figure which shows the color filter of the solid-state image sensor shown in FIG. The figure explaining another method of providing a sensitivity difference in the output signal of the pair of photoelectric conversion elements shown in FIG. The figure explaining another method of providing a sensitivity difference in the output signal of the pair of photoelectric conversion elements shown in FIG. Timing chart for explaining the operation of the digital camera shown in FIG. The figure which showed typically the state of the vertical charge transfer part at the time of wide D range imaging mode of the digital camera shown in FIG. The figure which showed typically the state of the vertical charge transfer part at the time of wide D range imaging mode of the digital camera shown in FIG. The figure which showed typically the state of the vertical charge transfer part at the time of wide D range imaging mode of the digital camera shown in FIG. The figure which shows the modification of the solid-state image sensor in the digital camera shown in FIG. Enlarged view of range XII in the solid-state imaging device shown in FIG.

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

  FIG. 1 is a diagram showing a schematic configuration of an imaging apparatus for explaining an embodiment of the present invention. Examples of the imaging device include an imaging device such as a digital camera and a digital video camera, an imaging module mounted on an electronic endoscope, a camera-equipped mobile phone, and the like. Here, a digital camera will be described as an example.

  The imaging system of the illustrated digital camera includes a photographing lens 1, a CCD (Charge Coupled Device) type solid-state imaging device 5, an aperture 2 provided between them, an infrared cut filter 3, and an optical low-pass filter 4. With. Although not shown, a mechanical shutter is provided in front of the photographing lens 1.

  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.

  In addition, 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 an imaging 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 single imaging instruction from the solid-state imaging device 5 A D range expansion processing unit 19 that generates one imaged data with an expanded dynamic range using three signals output to the external memory, an external memory control unit 20 to which a detachable recording medium 21 is connected, and a camera. And a display control unit 22 to which a liquid crystal display unit 23 mounted on the back surface or the like is connected. The memory control unit 15, the digital signal processing unit 17, the compression / decompression processing unit 18, the D range expansion processing unit 19, the external memory control unit 20, and the display control unit 22 are connected to each other by a control bus 24 and a data bus 25. It is controlled by a command from the system control unit 11.

  FIG. 2 is a schematic plan view showing a schematic configuration of the solid-state imaging device 5 in the digital camera shown in FIG. 2 includes a plurality of photoelectric conversion elements (a photoelectric conversion element 51 and a photoelectric conversion element 52), a plurality of vertical charge transfer units 53, a horizontal charge transfer unit 54, and an output unit 55. Prepare.

  The plurality of photoelectric conversion elements are arranged in a two-dimensional shape (in the example of FIG. 2, a square lattice shape) in the row direction X on the surface of the semiconductor substrate and the column direction Y orthogonal thereto. In addition, among the photoelectric conversion element columns composed of a plurality of photoelectric conversion elements arranged in the column direction Y, the photoelectric conversion elements that constitute the odd-numbered columns counted in the row direction X from the output unit 55 side are photoelectric conversions. Each photoelectric conversion element which is the element 52 and constitutes the photoelectric conversion element array in the even-numbered columns is the photoelectric conversion element 51.

  The photoelectric conversion element 51 and the photoelectric conversion element 52 each output a signal having a sensitivity difference. Various methods are known for outputting a signal having a difference in sensitivity between the photoelectric conversion element 51 and the photoelectric conversion element 52. In this solid-state image pickup device 5, the image pickup device driving unit 10 includes the photoelectric conversion device 51. And the photoelectric conversion element 52 are controlled to change the exposure time so that a signal having a sensitivity difference can be obtained. Another method for obtaining a signal having a sensitivity difference will be described later.

  The vertical charge transfer unit 53 transfers the signal charge accumulated in the photoelectric conversion elements 51 and 52 in the column direction Y, and includes a charge transfer channel formed in the semiconductor substrate and a plurality of the charge transfer channels provided thereabove. It consists of a transfer electrode.

  One vertical charge transfer unit 53 is provided at a position adjacent to each photoelectric conversion element array, corresponding to each photoelectric conversion element array. The positional relationship between each photoelectric conversion element array and the corresponding vertical charge transfer unit 53 is the same for all photoelectric conversion element arrays. In the example of the figure, a vertical charge transfer unit 53 corresponding to each photoelectric conversion element column is arranged on the left side of each photoelectric conversion element column. The charge generated in each photoelectric conversion element of each photoelectric conversion element array is read out to the vertical charge transfer unit 53 on the left side corresponding to each photoelectric conversion element array.

  The horizontal charge transfer unit 54 transfers the charges transferred from the plurality of vertical charge transfer units 53 in the row direction X. The charge transfer channel formed in the semiconductor substrate and the plurality of charge transfer channels provided thereabove. Transfer electrode.

  The output unit 55 converts the charge transferred from the horizontal charge transfer unit 54 into a voltage signal corresponding to the charge amount and outputs the voltage signal.

  In the following, a certain photoelectric conversion element 52 and a photoelectric conversion element 51 (for example, the photoelectric conversion element 51 on the right side of the photoelectric conversion element 52) disposed adjacent to each other with the vertical charge transfer unit 53 interposed therebetween are treated as a pair. The solid-state imaging device 5 will be described as having a plurality of pairs.

  In this digital camera, the D range expansion processing unit 19 uses a first signal and a second signal read from the photoelectric conversion elements 51 and 52 constituting the pair, and a smear signal described later (specifically). Specifically, these signals are combined) to generate pixel data corresponding to the pair.

  FIG. 3 is an enlarged view of a range III in the solid-state imaging device 5 shown in FIG. In FIG. 3, the opening K of the light shielding film provided above the photoelectric conversion elements 51 and 52 is also illustrated.

  The vertical charge transfer unit 53 of the solid-state imaging device 5 includes a linear charge transfer channel (charge transfer path) 53a formed in the semiconductor substrate and extending in the column direction Y, and transfer electrodes V1 to V6 provided above the linear charge transfer channel 53a. It consists of The charge transfer channel 53a is composed of, for example, an n-type impurity layer formed in a p-well layer on an n-type semiconductor substrate.

  Each of the photoelectric conversion elements 51 and 52 is provided with three transfer electrodes correspondingly. In the example of FIG. 3, each photoelectric conversion element 51 in the odd-numbered photoelectric conversion element row counted in the column direction Y from the end opposite to the end provided with the horizontal charge transfer unit 54 of the solid-state imaging device 5. , 52 are provided with transfer electrodes V1, V2, V3 correspondingly. Further, transfer electrodes V4, V5, and V6 are provided corresponding to the photoelectric conversion elements 51 and 52 in the even-numbered photoelectric conversion element rows.

  Six-phase drive pulses are supplied to the transfer electrodes V1 to V6 from the image sensor driving unit 10. The drive pulse includes a pulse VL for forming a barrier in the charge transfer channel 53a, a pulse VM for forming a potential well in the charge transfer channel 53a, and a charge transfer channel corresponding to this from the photoelectric conversion elements 51 and 52. 53a includes a pulse VH for reading out electric charges. The pulse VL is, for example, −8V, the pulse VM is, for example, 0V, and the pulse VH is, for example, 15V.

  The transfer electrode V1 also serves as a readout electrode for applying the pulse VH to the charge readout region 56 corresponding to the photoelectric conversion elements 51 in the odd-numbered photoelectric conversion element rows. By supplying the pulse VH to the transfer electrode V1, signal charges are read from the odd-numbered photoelectric conversion elements 51 to the charge transfer channel 53a corresponding thereto.

  The transfer electrode V3 also serves as a readout electrode for applying the pulse VH to the charge readout region 56 corresponding to the photoelectric conversion elements 52 in the odd-numbered photoelectric conversion element rows. By supplying the pulse VH to the transfer electrode V3, signal charges are read out from the odd-numbered photoelectric conversion elements 52 to the charge transfer channels 53a corresponding thereto.

  The transfer electrode V4 also serves as a readout electrode for applying the pulse VH to the charge readout region 56 corresponding to each photoelectric conversion element 51 in the even number of photoelectric conversion element rows. By supplying the pulse VH to the transfer electrode V4, the signal charge is read from the photoelectric conversion elements 51 in the even-numbered rows to the charge transfer channel 53a corresponding thereto.

  The transfer electrode V6 also serves as a readout electrode for applying the pulse VH to the charge readout region 56 corresponding to each photoelectric conversion element 52 in the even number of photoelectric conversion element rows. By supplying the pulse VH to the transfer electrode V6, the signal charge is read from the even number of photoelectric conversion elements 52 to the charge transfer channel 53a corresponding thereto.

  Since the color components of the signals obtained from the pair of the solid-state image pickup devices 5 need to be the same, the color filters FR, FB, and the like above the photoelectric conversion elements 51 and 52 of the solid-state image pickup device 5 as shown in FIG. FG is provided. The color filters FR, FB, and FG are provided for each pair, and the arrangement thereof is a Bayer shape.

  The color filter FR is an optical filter that transmits red light, and is integrated by photoelectric conversion elements 51 and 52 constituting a pair. That is, the color filter FR straddles the vertical charge transfer unit 53 between the photoelectric conversion element 51 and the photoelectric conversion element 52 from above the photoelectric conversion element 51 constituting the pair to above the photoelectric conversion element 52 constituting the pair. It is formed with.

  The color filter FG is an optical filter that transmits green light, and is integrated by photoelectric conversion elements 51 and 52 constituting a pair. That is, the color filter FG straddles the vertical charge transfer unit 53 between the photoelectric conversion element 51 and the photoelectric conversion element 52 from above the photoelectric conversion element 51 constituting the pair to above the photoelectric conversion element 52 constituting the pair. It is formed with.

  The color filter FB is an optical filter that transmits blue light, and is integrated by photoelectric conversion elements 51 and 52 constituting a pair. That is, the color filter FB straddles the vertical charge transfer unit 53 between the photoelectric conversion element 51 and the photoelectric conversion element 52 from above the photoelectric conversion element 51 constituting the pair to above the photoelectric conversion element 52 constituting the pair. It is formed with.

  As shown in FIG. 6, the color filter FR provided above the photoelectric conversion elements 51 and 52 is divided into the photoelectric conversion element 51 and the photoelectric conversion element 52, divided into areas CF1 and CF2, and the transmittances of the areas CF1 and CF2 are changed. By changing, it is possible to provide a sensitivity difference between the photoelectric conversion element 51 and the photoelectric conversion element 52. In the case of this configuration, it is difficult to integrate the color filters by the photoelectric conversion element 51 and the photoelectric conversion element 52, and therefore the color filters are formed separately.

  In the digital camera configured as described above, the three modes of the wide D range imaging mode, the high resolution imaging mode, and the high sensitivity imaging mode can be switched according to the subject or manually.

  In the wide D range imaging mode, the exposure times of the photoelectric conversion elements 51 and 52 are different from each other, and pixel data corresponding to the pair using signals having different sensitivities obtained from the photoelectric conversion elements 51 and 52 constituting the pair. Is the mode to generate.

  The high-resolution imaging mode is a mode in which the exposure times of the photoelectric conversion elements 51 and 52 are the same, and pixel data corresponding to each photoelectric conversion element is generated from a signal obtained from each photoelectric conversion element included in the solid-state imaging element 5. It is.

  In the high-sensitivity imaging mode, the exposure times of the photoelectric conversion elements 51 and 52 are the same, the signals obtained from the photoelectric conversion elements 51 and 52 constituting the pair are combined, and the pixel data with high sensitivity corresponding to the pair is obtained. This is the mode to generate.

  Hereinafter, an operation in the wide D range imaging mode will be described.

  FIG. 5 is a timing chart for explaining the operation of the digital camera shown in FIG. 1 in the wide D range imaging mode. 6 to 8 are diagrams schematically illustrating the state of the vertical charge transfer unit 53 when the digital camera illustrated in FIG. 1 is in the wide D range imaging mode. 6 to 8, the charge transfer channel 53a of the vertical charge transfer unit 53 is not shown.

  When preliminary imaging for performing AE and AF is completed and an instruction for main imaging is given, the imaging element driving unit 10 opens the mechanical shutter.

  Next, the image sensor driving unit 10 applies a high-voltage electronic shutter pulse to the semiconductor substrate of the solid-state image sensor 5, and also applies a pulse VH to the transfer electrodes V1, V3, V4, and V6, respectively. As a result, the charges accumulated in the photoelectric conversion element 51, the photoelectric conversion element 52, and the charge transfer channel 53a are discarded on the semiconductor substrate. The imaging element driving unit 10 stops the application of the electronic shutter pulse at the time t1 and stops the application of the pulse VH to the transfer electrodes V1, V3, V4, and V6, so that the exposure period (the length of the photoelectric conversion element 51 is increased). Time exposure) is started.

  When long exposure (long exposure) is started, signal charges corresponding to incident light are accumulated in the photoelectric conversion elements 51 and 52. The charge transfer channel 53a accumulates smear charges generated on the surfaces of the photoelectric conversion elements 51 and 52 and smear charges due to light that has entered without being shielded by the light shielding film.

  At time t2 after the elapse of a predetermined time from the start of the long exposure, the image sensor driving unit 10 applies a pulse VH to the transfer electrodes V3 and V6 to transfer the signal charge accumulated in the photoelectric conversion element 52 to the charge transfer channel 53a. Read to. At this time, short-time exposure (short exposure) of the photoelectric conversion element 52 is started. Next, the image sensor driving unit 10 applies pulses to the transfer electrodes V1 to V6, transfers the read signal charges at high speed, and sweeps them out (transfer a1).

  When the transfer a1 ends, the image sensor driving unit 10 applies the pulse VM to the transfer electrodes V2 and V5, and applies the pulse VL to the transfer electrodes V1, V3, V4, and V6. As a result, accumulation of smear charges is started at positions corresponding to the respective pairs of the charge transfer channels 53a (here, below the transfer electrodes V2 and V5 that are positions between the photoelectric conversion elements 51 and 52). The FIG. 6 shows the state at this time. Potential wells are formed in the transfer electrodes V2 and V5, and smear charges (circles in FIG. 6) are accumulated in these wells.

  At time t3 after the elapse of a predetermined time from the start of short exposure, the image sensor driving unit 10 closes the mechanical shutter. Thus, the long exposure and the short exposure are completed, and the accumulation of smear charges in the charge transfer channel 53a is also completed (end of the exposure period).

  Next, the image sensor driving unit 10 applies a pulse to the transfer electrodes V1 to V6 to transfer the smear charges accumulated under the transfer electrodes V2 and V5 (transfer a2 in FIG. 5), and to the smear charges. A corresponding smear signal is output from the solid-state imaging device 5. The smear signal output from the solid-state imaging device 5 is converted into a digital signal after analog signal processing and temporarily stored in the main memory 16.

  Next, the image sensor driving unit 10 applies a pulse VM to the transfer electrodes V3 to V6, and applies a pulse VL to the transfer electrodes V1 and V2. From this state, the pulse VH is applied to the transfer electrodes V4 and V6, and the signal charges are read from the photoelectric conversion elements 51 and 52 in the even-numbered rows to the charge transfer channel 53a. FIG. 7 shows the state at this time. In FIG. 7, □ marks indicate signal charges read from the photoelectric conversion element 51, and Δ marks indicate signal charges read from the photoelectric conversion element 52.

  Next, the image sensor driving unit 10 applies pulses to the transfer electrodes V1 to V6 to transfer the signal charges (Δ, □) read to the charge transfer channel 53a (transfer a3 in FIG. 5). A first signal corresponding to the signal charge □ and a second signal corresponding to the signal charge Δ are output from the solid-state imaging device 5. The signal output from the solid-state imaging device 5 is converted into a digital signal after analog signal processing and temporarily stored in the main memory 16.

  After the end of the transfer a3, the image sensor driving unit 10 applies the pulse VM to the transfer electrodes V1 to V4 and applies the pulse VL to the transfer electrodes V5 and V6. From this state, a pulse VH is applied to the transfer electrodes V1 and V3 to read out signal charges from the odd-numbered photoelectric conversion elements 51 and 52 to the charge transfer channel 53a. FIG. 8 shows the state at this time.

  Next, the image sensor driving unit 10 applies pulses to the transfer electrodes V1 to V6 to transfer the signal charges (Δ, □) read to the charge transfer channel 53a (transfer a4 in FIG. 5). A first signal corresponding to the signal charge □ and a second signal corresponding to the signal charge Δ are output from the solid-state imaging device 5. The signal output from the solid-state imaging device 5 is converted into a digital signal after analog signal processing and temporarily stored in the main memory 16.

  After completion of the transfer a4, the D range expansion processing unit 19 transmits the first signal and the second signal obtained from each pair stored in the main memory 16, and the charge transfer channel 53a (at the position corresponding to the pair). The smear signal obtained from the charge transfer channel 53a) between the pair is combined to generate a pixel signal corresponding to each pair. Next, the digital signal processing unit 17 performs digital signal processing on the pixel signal corresponding to each pair to generate image data (data composed of pixel data corresponding to each pair). Then, the image data is recorded on the recording medium 21, and the imaging operation ends.

  As described above, according to this digital camera, in the wide D range imaging mode, it is possible to obtain the first signal, the second signal, and the smear signal having different sensitivities corresponding to each pair. Also, pixel data can be generated using these signals. For this reason, it is possible to perform imaging with a larger dynamic range than before.

  In this digital camera, the smear charge accumulation position corresponding to the pair is a position covered by the color filter above the pair. For this reason, the color component of the smear signal corresponding to the pair can be matched with the color component of the first signal and the second signal corresponding to the pair. As a result, high-quality image data without color misregistration can be generated.

  Further, in this digital camera, the positions of the photoelectric conversion element 51 and the photoelectric conversion element 52 constituting the pair are the same in the column direction Y. Moreover, since the smear signal corresponding to this pair is acquired from the area | region between the photoelectric conversion element 51 and the photoelectric conversion element 52 which comprise this pair, each of a 1st signal, a 2nd signal, and a smear signal Can be made substantially the same in the column direction. As a result, the correlation between the first signal, the second signal, and the smear signal obtained corresponding to the pair can be increased, and high-quality image data can be generated.

  In this digital camera, smear signals are all read out in one field by progressive driving, and the first signal and the second signal are read out in two fields by interlace driving. Since the amount of smear charge is originally small, it can be transferred sufficiently even with progressive driving. On the other hand, the amount of signal charge accumulated in the photoelectric conversion elements 51 and 52 is sufficiently larger than the smear charge. For this reason, if all the data is read out in one field by progressive driving, the saturation charge amount of the photoelectric conversion elements 51 and 52 must be reduced or the long exposure period of the photoelectric conversion element 51 must be shortened. Therefore, the signal charges accumulated in the photoelectric conversion elements 51 and 52 are read out in two fields by interlace driving, so that a sufficient saturation charge amount of the photoelectric conversion elements 51 and 52 is secured, A long exposure period can be made sufficiently long, and a decrease in sensitivity can be prevented.

  In the example shown in FIG. 5, the short exposure is started from the middle of the long exposure in the exposure period, but the present invention is not limited to this. For example, in the exposure period, long exposure and short exposure may be started simultaneously, and short exposure may be ended first. In this case, after the long exposure is started, the signal charge is read from only the photoelectric conversion element 52 at an arbitrary timing, and this is transferred and the second signal is output from the solid-state imaging element 5. Thereafter, after the long exposure is completed, the smear charges accumulated between the end of reading the second signal and the end of the long exposure are transferred, and the smear signal is output from the solid-state imaging device 5. Finally, the signal charge is read from the photoelectric conversion element 51 and transferred to output the first signal.

  In this way, even when the dynamic range magnification is increased (when the short exposure is shortened), it is possible to increase the smear charge accumulation time.

  Further, the drive shown in FIG. 5 for starting the long exposure first and ending the long exposure and the short exposure at the same time, and the drive for starting the long exposure and the short exposure at the same time and ending the short exposure first are necessary. Switching may be performed according to the dynamic range magnification.

  In the above description, a plurality of photoelectric conversion elements including the photoelectric conversion element 51 and the photoelectric conversion element 52 are arranged in a square lattice shape, but the present invention is not limited to this. For example, the so-called honeycomb arrangement in which the odd-numbered photoelectric conversion element rows are shifted in the column direction by 1/2 of the column-direction arrangement pitch of the photoelectric conversion elements with respect to the even-numbered photoelectric conversion element rows may be employed.

  The color filter is not limited to RGB, and may be a complementary color filter such as cyan, magenta, and yellow. If color imaging is not required, all filters provided above each pair may be infrared light transmission filters, green light transmission filters, or the like.

  Further, the solid-state imaging device 5 in the digital camera shown in FIG. 1 may be changed to a solid-state imaging device 5 ′ having the configuration shown in FIG. 9.

  The solid-state imaging device 5 ′ illustrated in FIG. 9 deletes the vertical charge transfer unit 53 other than the vertical charge transfer unit 53 between the pair of photoelectric conversion elements 51 and 52, and the vertical charge transfer unit 53 between the columns. 2 is different from the solid-state imaging device 5 shown in FIG.

  FIG. 10 is an enlarged view of a range XII of the solid-state imaging device 5 ′ illustrated in FIG. 9. In the solid-state imaging device 5 ′, a charge readout region 56 is formed between the photoelectric conversion elements 51 and 52 constituting a pair and the charge transfer channel 53 a between them. In the example of FIG. 10, the transfer electrodes V1, V3, V4, V6 also serve as readout electrodes.

  In the solid-state imaging device 5 ′ shown in FIG. 9, after the long exposure, the smear signal corresponding to the smear charge accumulated under the transfer electrodes V <b> 2 and V <b> 5 is read during the exposure period. Thereafter, a pulse VH is applied to the transfer electrode V1, signal charges are read from the odd-numbered photoelectric conversion elements 51, and a first signal corresponding to the signal charges is output. Subsequently, a pulse VH is applied to the transfer electrode V4, signal charges are read from the photoelectric conversion elements 51 in even-numbered rows, and a first signal corresponding to the signal charges is output.

  Subsequently, the pulse VH is applied to the transfer electrode V3, the signal charge is read from the odd-numbered photoelectric conversion elements 52, and a second signal corresponding to the signal charge is output. Subsequently, a pulse VH is applied to the transfer electrode V6, signal charges are read from the photoelectric conversion elements 52 in the even-numbered rows, and a second signal corresponding to the signal charges is output.

  As described above, the smear signal is read by progressive driving, and the first signal and the second signal are read by four-field interlace driving, thereby expanding the dynamic range while preventing the sensitivity of the photoelectric conversion elements 51 and 52 from being lowered. be able to.

  Next, another method for outputting a signal having a difference in sensitivity between the photoelectric conversion element 51 and the photoelectric conversion element 52 will be described.

  FIG. 11 is a diagram for explaining another method for outputting a signal having a difference in sensitivity between the photoelectric conversion element 51 and the photoelectric conversion element 52 illustrated in FIG. 2. As shown in FIG. 11, by changing the size of the opening K of the light shielding film provided above the photoelectric conversion elements 51 and 52 between the photoelectric conversion element 51 and the photoelectric conversion element 52, the photoelectric conversion element 51 and the photoelectric conversion element 52 are changed. A sensitivity difference can be provided.

  12 is a view for explaining still another method of providing a sensitivity difference between the photoelectric conversion element 51 and the photoelectric conversion element 52 shown in FIG. 2, and is a view showing a VI-VI cross section of FIG. A symbol W shown in FIG. 12 indicates a light shielding film.

  As shown in FIG. 12, the color filter FR provided above the photoelectric conversion elements 51 and 52 is divided into the photoelectric conversion element 51 and the photoelectric conversion element 52, divided into areas CF1 and CF2, and the transmittances of the areas CF1 and CF2 are changed. By changing, it is possible to provide a sensitivity difference between the photoelectric conversion element 51 and the photoelectric conversion element 52. In the case of this configuration, it is difficult to integrate the color filters by the photoelectric conversion element 51 and the photoelectric conversion element 52, and therefore the color filters are formed separately.

  As described above, the following items are disclosed in this specification.

  The disclosed imaging apparatus is an imaging apparatus including a solid-state imaging device and a signal processing unit that generates one image data using a plurality of signals read out in a plurality of fields from the solid-state imaging device, The solid-state imaging device includes a plurality of photoelectric conversion elements and a charge transfer path that transfers signal charges accumulated in the photoelectric conversion elements, and the plurality of photoelectric conversion elements are arranged in proximity to each other with a difference in sensitivity. A plurality of pairs of a first photoelectric conversion element and a second photoelectric conversion element that output a signal, and the charge transfer between the first photoelectric conversion element and the second photoelectric conversion element of the pair A path is provided, and the charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element of the pair can be driven to accumulate smear charges at a position corresponding to the pair. And the signal The logic unit includes a first signal corresponding to the signal charge accumulated in the first photoelectric conversion element of the pair and a second signal corresponding to the signal charge accumulated in the second photoelectric conversion element of the pair. And the third signal corresponding to the smear charge accumulated by the driving at the position of the charge transfer path corresponding to the pair are generated.

  With this configuration, the first signal, the second signal, and the third signal having different sensitivities can be obtained. By generating image data using the first signal, the second signal, and the third signal, the dynamic range can be expanded more than in the past. it can.

  In the disclosed imaging device, the first photoelectric conversion element and the second photoelectric conversion element of the pair each have a color filter that transmits light of the same color above, and the first photoelectric conversion The color filter above the element and the color filter above the second photoelectric conversion element are integrally formed across the charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element. And the position corresponding to the pair is the color filter above the charge transfer path of the charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element of the pair. It is in the covered area.

  With this configuration, since the color filter provided above the first photoelectric conversion element and the second photoelectric conversion element is provided above the position where the smear charge is accumulated, the first signal and the second And the color components of the third signal can be matched, and a color image with an expanded dynamic range can be obtained.

  In the disclosed imaging device, the plurality of photoelectric conversion elements include a first column in which the first photoelectric conversion elements are arranged in a column direction, and a second column in which the second photoelectric conversion elements are arranged in the column direction. Are arranged alternately in the row direction orthogonal to the column direction, and the first column and the second column are adjacent to each other in the same positional relationship with each other. The charge transfer path is provided correspondingly, and the signal charge accumulated in the photoelectric conversion element is transferred between the charge transfer path and the photoelectric conversion element corresponding to the charge transfer path. A charge readout region for reading out to the path is formed.

  With this configuration, it is possible to perform imaging with a wide dynamic range without greatly changing the configuration from a general-purpose solid-state imaging device.

  In the disclosed imaging device, the plurality of photoelectric conversion elements include a first column in which the first photoelectric conversion elements are arranged in a column direction, and a second column in which the second photoelectric conversion elements are arranged in the column direction. Are alternately arranged in a row direction orthogonal to the column direction, and the charge is alternately arranged in the row direction between the first column and the second column. A transfer path is provided, and signal charges accumulated in the photoelectric conversion element are read out to the charge transfer path between the charge transfer path and the photoelectric conversion element on the side of the charge transfer path. For this purpose, a charge readout region is formed.

  With this configuration, the number of charge transfer paths can be reduced, and accordingly, the number of pixels can be increased and the pixel size can be increased.

  In the disclosed imaging apparatus, the first photoelectric conversion element and the second photoelectric conversion element of the pair have the same position in the column direction.

  With this configuration, the sampling points of the first signal, the second signal, and the third signal can be matched in the column direction. For this reason, imaging data with a small sampling point shift can be obtained.

  The disclosed imaging apparatus includes a driving unit that drives the solid-state imaging device so that the third signal is read out in one field, and the first signal and the second signal are read out in a plurality of fields. It is to be prepared.

  With this configuration, the transfer capacity of the charge transfer path when reading the first signal and the second signal can be increased. For this reason, the saturation charge amount of the photoelectric conversion element can also be increased, leading to an improvement in sensitivity.

  The disclosed image pickup apparatus provides the difference in sensitivity by performing control for differentiating the exposure time between the first photoelectric conversion element and the second photoelectric conversion element.

  With this configuration, the structure of each pixel can be made the same.

  The disclosed imaging apparatus starts the exposure of the first photoelectric conversion element first, starts the exposure of the second photoelectric conversion element in the middle thereof, and performs the exposure during the exposure of the second photoelectric conversion element. It is to drive.

  The disclosed imaging apparatus simultaneously starts exposure of the first photoelectric conversion element and the second photoelectric conversion element, and exposes the second photoelectric conversion element in the middle of the exposure of the first photoelectric conversion element. And after reading the second signal from the second photoelectric conversion element in the exposure of the second photoelectric conversion element, until the exposure of the first photoelectric conversion element is completed, It is to drive.

  The disclosed imaging apparatus starts the exposure of the first photoelectric conversion element first, starts the exposure of the second photoelectric conversion element in the middle thereof, and performs the exposure during the exposure of the second photoelectric conversion element. First mode of driving, and exposure of the first photoelectric conversion element and the second photoelectric conversion element are started simultaneously, and the second photoelectric conversion element is in the middle of exposure of the first photoelectric conversion element And after the second signal is read from the second photoelectric conversion element in the exposure of the second photoelectric conversion element, until the exposure of the first photoelectric conversion element is completed. The second mode in which the driving is performed is switched according to the dynamic range magnification.

5 Solid-state imaging devices 51 and 52 Photoelectric conversion device 53 Vertical charge transfer unit 53a Charge transfer channel V1 to V6 Transfer electrode 19 D range expansion processing unit

Claims (10)

An imaging apparatus comprising: a solid-state imaging device; and a signal processing unit that generates one image data using a plurality of signals read out in a plurality of fields from the solid-state imaging device,
The solid-state imaging element includes a plurality of photoelectric conversion elements, and a charge transfer path that transfers signal charges accumulated in the photoelectric conversion elements,
The plurality of photoelectric conversion elements have a plurality of pairs of a first photoelectric conversion element and a second photoelectric conversion element that output signals having a difference in sensitivity arranged close to each other,
The charge transfer path is provided between the first photoelectric conversion element and the second photoelectric conversion element of the pair,
The charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element of the pair can be driven to accumulate smear charges at a position corresponding to the pair,
The signal processing unit corresponds to a first signal corresponding to the signal charge accumulated in the first photoelectric conversion element of the pair and a signal charge accumulated in the second photoelectric conversion element of the pair. An imaging apparatus that generates the image data using a second signal and a third signal corresponding to the smear charge accumulated by the driving at a position of the charge transfer path corresponding to the pair. The imaging apparatus according to claim 1,
The first photoelectric conversion element and the second photoelectric conversion element of the pair each have a color filter that transmits light of the same color above,
The charge transfer between the first photoelectric conversion element and the second photoelectric conversion element is performed by the color filter above the first photoelectric conversion element and the color filter above the second photoelectric conversion element. It is united across the road,
A position corresponding to the pair is covered with the color filter above the charge transfer path of the charge transfer path between the first photoelectric conversion element and the second photoelectric conversion element of the pair. An imaging device in the area. The imaging apparatus according to claim 1 or 2,
The plurality of photoelectric conversion elements includes a first column in which the first photoelectric conversion elements are arranged in a column direction, and a second column in which the second photoelectric conversion elements are arranged in the column direction. It is arranged alternately in the row direction orthogonal to the direction,
In the first row and the second row, the charge transfer paths are provided correspondingly adjacent to each other in the same positional relationship with each other,
Between the charge transfer path and the photoelectric conversion element corresponding to the charge transfer path, a charge reading region for reading the signal charge accumulated in the photoelectric conversion element to the charge transfer path is formed. Imaging device. The imaging apparatus according to claim 1 or 2,
The plurality of photoelectric conversion elements includes a first column in which the first photoelectric conversion elements are arranged in a column direction, and a second column in which the second photoelectric conversion elements are arranged in the column direction. It is arranged alternately in the row direction orthogonal to the direction,
Between the first column and the second column, every other charge transfer path is provided in the row direction,
Between the charge transfer path and the photoelectric conversion element adjacent to the charge transfer path, a charge reading region for reading the signal charge accumulated in the photoelectric conversion element to the charge transfer path is formed. Imaging device. The imaging measure according to claim 3 or 4,
The imaging device in which the position in the column direction of each of the first photoelectric conversion element and the second photoelectric conversion element of the pair is the same. The imaging device according to any one of claims 1 to 5,
An imaging apparatus comprising a drive unit that drives the solid-state imaging device so that the third signal is read out in one field, and the first signal and the second signal are read out in a plurality of fields. The imaging apparatus according to any one of claims 1 to 6,
An imaging apparatus that provides the difference in sensitivity by performing a control for making a difference in exposure time between the first photoelectric conversion element and the second photoelectric conversion element. The imaging apparatus according to claim 7,
An imaging apparatus that starts exposure of the first photoelectric conversion element first, starts exposure of the second photoelectric conversion element in the middle thereof, and performs the driving during the exposure of the second photoelectric conversion element. The imaging apparatus according to claim 7,
The exposure of the first photoelectric conversion element and the second photoelectric conversion element is started at the same time, the exposure of the second photoelectric conversion element is completed in the middle of the exposure of the first photoelectric conversion element, and the second An image pickup apparatus that performs the driving after reading the second signal from the second photoelectric conversion element by the exposure of the photoelectric conversion element until the exposure of the first photoelectric conversion element is completed. The imaging apparatus according to claim 7,
The first mode in which the exposure of the first photoelectric conversion element is started first, the exposure of the second photoelectric conversion element is started in the middle, and the driving is performed during the exposure of the second photoelectric conversion element When,
The exposure of the first photoelectric conversion element and the second photoelectric conversion element is started at the same time, the exposure of the second photoelectric conversion element is completed in the middle of the exposure of the first photoelectric conversion element, and the second The second mode in which the driving is performed after the second signal is read from the second photoelectric conversion element in the exposure of the photoelectric conversion element until the exposure of the first photoelectric conversion element is completed. An imaging device that switches between and according to the dynamic range magnification.

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