JP2006339272A - Solid-state imaging apparatus, solid-state imaging device, driver ic, and method of driving solid-state imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging apparatus capable of reducing power consumption without decreasing the amount of saturation signal. <P>SOLUTION: A vertical and horizontal driver circuit 102 outputs drive signals ϕV1-ϕV4, a drive signal ϕHL, and a reset signal ϕR. A horizontal driver circuit 103 outputs drive signals ϕH1 and ϕH2. A horizontal CCD 107 transmits signal charge in a horizontal direction by the drive signals ϕHL, ϕH1, and ϕH2. The potential difference between the drive signals ϕH1 and ϕH2 is smaller than that between the drive signal ϕHL and the reset one ϕR. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device, a solid-state imaging device, a driver IC, and a driving method of the solid-state imaging device.

  FIG. 10 is a diagram showing a schematic configuration of a conventional solid-state imaging device 900. As shown in FIG. In FIG. 10, a conventional solid-state imaging device 900 includes a solid-state imaging device 901, a vertical driver circuit 902, a horizontal driver circuit 903, and an output amplifier 904. The solid-state imaging device 901 includes a plurality of photoelectric conversion elements 905 arranged in a matrix, a plurality of vertical CCDs (Charge Coupled Devices) 906, a horizontal CCD 907, and an output unit 908.

  The photoelectric conversion element 905 generates a signal charge according to the intensity of incident light.

  The vertical CCD 906 has four transfer electrodes corresponding to the two photoelectric conversion elements 905. Four-phase drive signals φV1, φV2, φV3, and φV4 are input to the four transfer electrodes, respectively. When the drive signals φV1, φV2, φV3, and φV4 are input, the vertical CCD 906 is driven in four phases and transfers the signal charges obtained by the photoelectric conversion element 905 in the vertical direction.

  A horizontal CCD 907 is disposed at the output side end of the vertical CCD 906. The horizontal CCD 907 has four transfer electrodes corresponding to one vertical CCD 906. The four transfer electrodes are a set of two adjacent transfer electrodes. Two-phase drive signals φH1 and φH2 are input to each pair of transfer electrodes. The horizontal CCD 907 has two transfer electrodes at the output end. A drive signal φHL having the same amplitude and the same phase as the drive signal φH1 is input to the two transfer electrodes. When the drive signals φH1, φH2, and φHL are input, the horizontal CCD 907 is driven in two phases to transfer the signal charge from the vertical CCD 906 in the horizontal direction.

  On the output side of the horizontal CCD 907, an output unit 908 for outputting signal charges is disposed. The output unit 908 includes an output gate 909, a floating diffusion 910, a reset gate 911, and a reset drain 912. A signal OG having a constant voltage is input to the output gate 909. The signal charge transferred from the horizontal CCD 907 is converted into a voltage by the floating diffusion 910, amplified by the output amplifier 904, and output as the output signal Vout. A reset signal φR is input to the reset gate 911. When the reset signal φR is turned on, the floating diffusion 910 is reset to the voltage RD of the reset drain 912. Immediately after the reset operation, the voltage of the floating diffusion 910 becomes the reference voltage. Therefore, the difference between the reference voltage and the voltage corresponding to the next signal charge is the output signal.

  In the conventional solid-state imaging device 900, the drive signals φV1, φV2, φV3, and φV4 are supplied by the vertical driver circuit 902. Further, the drive signals φH1, φH2, and φHL and the reset signal φR are supplied by the horizontal driver circuit 903.

  FIG. 11 is a timing chart of drive signals φH1, φH2, and φHL, a reset signal φR, and an output signal in the conventional solid-state imaging device 900. 12 is a cross-sectional view and potential distribution of the horizontal CCD 907 and the output unit 908 shown in FIG. 10 taken along line AB. Hereinafter, horizontal transfer and charge detection in the conventional solid-state imaging device 900 will be described with reference to FIGS. 11 and 12.

  As shown in FIG. 11, in the conventional solid-state imaging device 900, the drive signals φH1, φH2, and φHL and the reset signal φR all have the same potential difference (for example, 3.3 V). The drive signals φH1 and φHL have the same amplitude and phase. The drive signals φH1 and φH2 have the same amplitude and opposite phase. The reset signal φR rises at the same timing as the drive signal φHL rises.

  As shown in FIGS. 11 and 12, at time t1, the drive signals φH1 and φHL become high and the drive signal φH2 becomes low, so that the signal charge transferred from the vertical CCD 906 is input with the drive signal φH1. Is accumulated in the potential well under the electrode (the electrode in which the impurity concentration just below the two electrodes is not changed). Further, the signal charge transferred from the horizontal CCD 907 has a potential at the output end below the electrode to which the drive signal φHL is input (the electrode in which the impurity concentration just below the two electrodes is not changed). Accumulated in the wells. Further, at time t1, since the reset signal φR becomes high, the floating diffusion (FDA) is reset to the voltage of the reset drain (RD).

  At time t2, drive signals φH1 and φHL are high, drive signal φH2 is low, and reset signal φR is low. At this time, as shown in FIG. 12, preparations for storing signal charges in the floating diffusion (FDA) are completed.

  At time t3, drive signals φH1 and φHL become low, and drive signal φH2 becomes high. At this time, as shown in FIG. 12, the signal charge below the electrode to which the drive signal φH1 is input moves toward the potential well below the electrode to which the drive signal φH2 is input. In addition, the signal charge under the electrode to which the drive signal φHL is input moves toward the potential well under the floating diffusion (FDA).

  At time t4, the signal charge transferred to the floating diffusion (FDA) is converted into a voltage and output as an output signal.

Thereafter, the horizontal CCD 907 transfers signal charges by repeating the input of the drive signals φH1, φH2, and φHL and the reset signal φR.
JP-A-5-95008

  In recent years, there has been a demand for lower power consumption of solid-state imaging devices. As a measure for reducing the power consumption, it is conceivable to reduce the voltage of the drive signal. In particular, if the voltage of a signal output from the horizontal driver circuit 903 that requires high-speed operation can be lowered, power consumption can be greatly reduced. However, simply lowering the voltage of the signal output from the horizontal driver circuit 903 causes a problem of high illuminance due to a decrease in the saturation signal amount and / or a post-feed phenomenon as described below.

  FIG. 13 is a diagram for explaining a decrease in the saturation signal amount due to a voltage decrease in the reset signal φR. Of the signals output from the horizontal driver circuit 903, when the voltage of the reset signal φR is lowered, the signal charges accumulated in the floating diffusion are not completely reset. Therefore, the signal charge accumulated in the floating diffusion is reduced. Therefore, the difference between the reference voltage and the signal voltage is reduced, the saturation signal amount is reduced, and as a result, the image obtained from the output signal is increased in illuminance.

  FIG. 14 is a diagram for explaining the post-feed phenomenon. Of the signals output from the horizontal driver circuit 903, when the drive signal φHL is lowered, the potential below the electrode to which the drive signal φHL is input is lowered, so that the potential of the signal charge accumulated in the electrode becomes the output gate. It becomes lower than the potential of (OG). Therefore, the signal charge moves over the OG barrier toward the floating diffusion (FDA), and a forward feed phenomenon occurs.

  FIG. 15 is a diagram for explaining the increase in illuminance due to the occurrence of the advance phenomenon. As shown in FIG. 14, when the advance feed phenomenon occurs, the feedthrough indicating the reference voltage is crushed even when the drive signal φHL is at a high level. When the feedthrough collapse occurs, the saturation signal amount decreases, and as a result, the image obtained from the output signal becomes highly illuminated.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a solid-state imaging device, a solid-state imaging device, a driver IC, and a driving method for the solid-state imaging device that can reduce power consumption without reducing a saturation signal amount.

  In order to solve the above problems, the present invention has the following features. The present invention is a solid-state imaging device, a photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and A horizontal CCD unit that horizontally transfers the signal charge transferred by the vertical CCD unit, and an output unit that is connected to the output terminal of the horizontal CCD unit and converts the signal charge transferred in the horizontal direction into a voltage and outputs the voltage. A vertical drive signal for driving the vertical CCD unit, a final horizontal drive signal for input to the final electrode unit including at least the final electrode at the output end of the horizontal CCD unit, and a reset gate in the output unit And a horizontal driver circuit for inputting a previous horizontal drive signal to the electrodes in the horizontal CCD unit other than the electrodes included in the final stage electrode unit. That. The final electrode portion is wired separately from the horizontal CCD electrode other than the final electrode portion. The potential difference of the front horizontal drive signal is smaller than the potential difference of at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal.

  Thus, since the potential difference of the previous horizontal drive signal is set low, the power consumption of the horizontal CCD unit that outputs the previous horizontal drive signal is reduced. By setting the final stage horizontal drive signal high, it is possible to avoid the forward feed phenomenon. In addition, the floating diffusion can be completely reset by setting the potential difference of the reset signal high. Therefore, a solid-state imaging device capable of reducing power consumption without reducing the saturation signal amount is provided.

  Preferably, the final-stage horizontal drive signal and the previous-stage horizontal drive signal have different phases.

  Preferably, the front-stage horizontal drive signal includes a first front-stage horizontal drive signal and a second front-stage horizontal drive signal for two-phase drive, and the final-electrode drive input to the final electrode among the final-stage horizontal drive signals The signal may rise earlier than the rising timing of the first previous horizontal driving signal, and fall earlier than the falling timing of the first previous horizontal driving signal.

  Thus, by advancing the phase of the final electrode driving signal, the signal charge moves to the floating diffusion at an early timing. Therefore, the signal time becomes longer than in the prior art. Accordingly, the amount of integrated signal increases. As a result, a solid-state imaging device capable of increasing the integrated signal amount and reducing the power consumption without reducing the saturation signal amount is provided.

  Preferably, the front-stage horizontal drive signal includes a first front-stage horizontal drive signal and a second front-stage horizontal drive signal for two-phase drive, and the final-electrode drive input to the final electrode among the final-stage horizontal drive signals The signal may rise later than the rising timing of the first previous horizontal driving signal, and fall later than the falling timing of the first previous horizontal driving signal.

  Thus, by delaying the phase of the final electrode drive signal, the feedthrough period serving as the reference signal can be lengthened. Therefore, noise can be reduced.

  Preferably, the front horizontal drive signal includes a first front horizontal drive signal and a second front horizontal drive signal for two-phase driving, and the reset signal is later than the rising timing of the first front horizontal drive signal. You should stand up.

  In this way, by delaying the phase of the reset signal, the signal charge accumulated in the floating diffusion is reset at a later timing than in the prior art. Accordingly, the amount of integrated signal increases. As a result, a solid-state imaging device capable of increasing the integrated signal amount and reducing the power consumption without reducing the saturation signal amount is provided.

  Preferably, the front-stage horizontal drive signal includes a first front-stage horizontal drive signal and a second front-stage horizontal drive signal for two-phase drive, and the reset signal is earlier than the rising timing of the first front-stage horizontal drive signal. You should stand up.

  In this way, the feedthrough period serving as the reference signal can be lengthened by advancing the phase of the reset signal. Therefore, noise can be reduced.

  Preferably, the final stage electrode section tapers toward the floating diffusion in the output section, and the final stage horizontal drive signal drives a final electrode drive signal for driving the final electrode and an electrode other than the final electrode. The middle stage electrode drive signal is synchronized with the previous stage horizontal drive signal, and the potential difference of the middle stage electrode drive signal is preferably larger than the potential difference of the previous stage horizontal drive signal.

  As described above, since a driving signal having a high voltage is input to the final stage electrode portion, a well having a potential of an appropriate depth can be formed, so that signal charges can be appropriately transferred to the floating diffusion. it can.

  The present invention also relates to a solid-state imaging device, a photoelectric conversion element unit that generates a signal charge corresponding to the intensity of incident light, and a vertical CCD that transfers the signal charge generated by the photoelectric conversion element unit in the vertical direction. Unit, a horizontal CCD unit for transferring the signal charge transferred by the vertical CCD unit in the horizontal direction, and an output connected to the output terminal of the horizontal CCD unit for converting the signal charge transferred in the horizontal direction into a voltage and outputting the voltage A part. A vertical drive signal for transferring signal charges in the vertical direction is input to the vertical CCD unit. The final stage electrode part including at least the final electrode at the output end of the horizontal CCD part is wired separately and independently from the horizontal CCD electrode other than the final stage electrode part. The final stage horizontal drive signal for transferring the signal charge accumulated in is input. A reset signal is input to the reset gate in the output unit. A front horizontal drive signal for transferring signal charges accumulated under the electrodes is input to the electrodes in the horizontal CCD unit other than the electrodes included in the final electrode unit. The potential difference of the front horizontal drive signal is smaller than the potential difference of at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal.

  Further, the present invention includes a photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and a vertical CCD unit. A solid-state imaging device comprising: a horizontal CCD unit that transfers the transferred signal charge in the horizontal direction; and an output unit that is connected to the output terminal of the horizontal CCD unit and converts the signal charge transferred in the horizontal direction into a voltage and outputs the voltage. A vertical drive signal for transferring a signal charge in the vertical direction is input to the vertical CCD unit, and includes at least a final electrode at an output end of the horizontal CCD unit, and the final stage electrode unit The final stage horizontal drive signal for transferring the signal charge accumulated under the final stage electrode part is input to the final stage electrode part wired separately and independently from the horizontal CCD electrode, and the output part Lise The reset signal is input to the gate, and the previous horizontal drive signal for transferring the signal charge accumulated under the electrode is input to the electrodes in the horizontal CCD unit other than the electrodes included in the final-stage electrode unit. The potential difference of the horizontal drive signal is smaller than the potential difference of at least one of the vertical drive signal, the final stage horizontal drive signal, and the reset signal.

  Further, the present invention includes a photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and a vertical CCD unit. A solid-state imaging device comprising: a horizontal CCD unit that transfers the transferred signal charge in the horizontal direction; and an output unit that is connected to the output terminal of the horizontal CCD unit and converts the signal charge transferred in the horizontal direction into a voltage and outputs the voltage. Is a driver IC for driving. The driver IC inputs a vertical drive signal for transferring a signal charge in the vertical direction to the vertical CCD unit, includes at least a final electrode at an output end of the horizontal CCD unit, and a horizontal CCD electrode other than the final stage electrode unit The final stage horizontal drive signal for transferring the signal charge accumulated under the final stage electrode part is input to the final stage electrode part, which is wired separately and independently, and the reset gate in the output part is reset. Input the signal. The potential difference of at least one of the vertical drive signal, the final stage horizontal drive signal, and the reset signal is greater than the potential difference of the previous horizontal drive signal input to the electrodes in the horizontal CCD unit other than the electrodes included in the final stage electrode unit. .

  Further, the present invention includes a photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and a vertical CCD unit. A solid-state imaging device comprising: a horizontal CCD unit that transfers the transferred signal charge in the horizontal direction; and an output unit that is connected to the output terminal of the horizontal CCD unit and converts the signal charge transferred in the horizontal direction into a voltage and outputs the voltage. Is a driver IC for driving. A vertical drive signal for transferring signal charges in the vertical direction is input to the vertical CCD unit. The final stage electrode unit including at least the final electrode at the output end of the horizontal CCD unit and wired separately from the horizontal CCD electrode other than the final stage electrode unit is accumulated below the final stage electrode unit. The final horizontal drive signal for transferring the signal charge is input. A reset signal is input to the reset gate in the output unit. The driver IC inputs a previous-stage horizontal drive signal for transferring signal charges accumulated under the electrodes to the electrodes in the horizontal CCD unit other than the electrodes included in the final-stage electrode unit. The potential difference of the front horizontal drive signal is smaller than the potential difference of at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal.

  According to the present invention, since the potential difference of the previous horizontal drive signal is set low, the power consumption of the horizontal CCD unit that outputs the previous horizontal drive signal is reduced. Since the final stage horizontal drive signal is set high, the forward feed phenomenon can be avoided. Further, since the potential difference of the reset signal is set high, the floating diffusion can be completely reset. Therefore, a solid-state imaging device, a solid-state imaging device, a driver IC, and a driving method for the solid-state imaging device that can reduce power consumption without reducing the saturation signal amount are provided.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of a solid-state imaging apparatus 100 according to the first embodiment of the present invention. In FIG. 1, the solid-state imaging device 100 includes a solid-state imaging device 101, a vertical and horizontal driver circuit 102, a horizontal driver circuit 103, and an output amplifier 104. The solid-state imaging device 101 includes a plurality of photoelectric conversion elements 105 arranged in a matrix, a plurality of vertical CCDs 106, a horizontal CCD unit 107, and an output unit 108. The plurality of photoelectric conversion elements 105 are collectively referred to as a photoelectric conversion element unit. The plurality of vertical CCDs 106 are collectively referred to as a vertical CCD unit.

  Each photoelectric conversion element 105 generates a signal charge according to the intensity of light.

  Each vertical CCD 106 has four transfer electrodes corresponding to the two photoelectric conversion elements 105. Four-phase drive signals (vertical drive signals) φV1, φV2, φV3, and φV4 are input to the four transfer electrodes, respectively. When the drive signals φV1, φV2, φV3, and φV4 are input, the vertical CCD 106 is driven in four phases and transfers signal charges obtained by the photoelectric conversion element 105 in the vertical direction. In this embodiment, the vertical CCD 106 transfers signal charges by four-phase driving, but may transfer signal charges by a driving method other than four-phase driving, such as three-phase driving.

  A horizontal CCD unit 107 is disposed at the output end of the vertical CCD 106. Here, the horizontal CCD unit 107 is configured by one horizontal CCD, but may be configured by a plurality of horizontal CCDs. The case where the horizontal CCD unit 107 is composed of a plurality of horizontal CCDs will be described later. The horizontal CCD unit 107 has four transfer electrodes corresponding to one vertical CCD 106. The four transfer electrodes are a set of two adjacent transfer electrodes. Two-phase drive signals (previous horizontal drive signals) φH1 and φH2 are input to each pair of transfer electrodes. The horizontal CCD unit 107 includes a final electrode unit 107a having a final electrode 107b and an electrode 107c adjacent thereto at the output end. The final electrode portion 107 a is wired separately from the horizontal CCD electrodes other than the electrodes of the final electrode portion 107 a in the horizontal CCD portion 107. A drive signal (final horizontal drive signal) φHL is input to the final electrode 107b and the electrode 107c. When the driving signals φH1, φH2, and φHL are input, the horizontal CCD unit 107 performs two-phase driving and transfers signal charges from the vertical CCD 106 in the horizontal direction. In the present embodiment, the horizontal CCD unit 107 has four transfer electrodes corresponding to one vertical CCD 106. However, the horizontal CCD unit 107 may be two-phase driven by having two transfer electrodes corresponding to one vertical CCD 106. In this case, the impurity concentration is preferably adjusted under each transfer electrode.

  On the output side of the horizontal CCD unit 107, an output unit 108 that converts a signal charge into a voltage and outputs the voltage is disposed. The output unit 108 includes an output gate 109, a floating diffusion 110, a reset gate 111, and a reset drain 112. A signal OG having a constant voltage is input to the output gate 109. The signal charge transferred from the horizontal CCD unit 107 is converted into a voltage by the floating diffusion 110, amplified by the output amplifier 104, and output as an output signal Vout. A reset signal φR is input to the reset gate 111. When the reset signal φR is turned on, the floating diffusion 110 is reset to the voltage RD of the reset drain 112. Immediately after the reset operation, the voltage of the floating diffusion 110 becomes the reference voltage. Therefore, the difference between the reference voltage and the voltage corresponding to the next signal charge is the output signal.

  The vertical horizontal driver circuit 102 outputs drive signals (vertical drive signals) φV1, φV2, φV3, and φV4, a drive signal (final stage horizontal drive signal) φHL, and a reset signal φR. In the present embodiment, it is assumed that 3.3 V is supplied to the vertical and horizontal driver circuit 102, for example.

  The horizontal driver circuit 103 outputs drive signals (previous horizontal drive signals) φH1 and φH2. In the present embodiment, it is assumed that 1.8 V is supplied to the horizontal driver circuit 103, for example. Note that the voltages supplied to the vertical and horizontal driver circuits 102 and 103 are not limited to the above example. However, it is assumed that the vertical and horizontal driver circuit 102 is a driver IC that can handle a higher voltage than the horizontal driver circuit 103.

  FIG. 2 is a timing chart of the drive signals φH1, φH2, and φHL, the reset signal φR, and the output signal in the solid-state imaging device 100. FIG. 3 is a cross-sectional view and potential distribution along line AB of the horizontal CCD unit 107 and the output unit 108 shown in FIG. Hereinafter, horizontal transfer and charge detection in the solid-state imaging device 100 will be described with reference to FIGS. 2 and 3.

  As shown in FIG. 2, in the solid-state imaging device 100, the drive signals φH1 and φH2 both have the same potential difference (for example, 1.8 V). Both drive signal φHL and reset signal φR have the same potential difference (for example, 3.3 V). Thus, in this embodiment, the drive signal φHL and the reset signal φR are driven independently of the drive signals φH1 and φH2. The potential difference between drive signals φH1 and φH2 is smaller than the potential difference between drive signal φHL and reset signal φR. Note that the potential difference of the drive signal φHL and the potential difference of the reset signal φR may not be the same. The drive signals φH1 and φH2 have the same amplitude and opposite phase. Drive signal φHL has the same phase as drive signal φH1, but the amplitude of drive signal φH1 is smaller than the amplitude of drive signal φHL. The reset signal φR rises at the same timing as the drive signal φH1 rises.

  At time t1, the drive signals φH1 and φHL become high and the drive signal φH2 becomes low. Therefore, as shown in FIG. 3, the signal charge transferred from the vertical CCD 106 is an electrode to which the drive signal φH1 is input ( Of the two electrodes, the impurity concentration directly below is accumulated in the potential well below the electrode that has not been changed. Further, the signal charge transferred from the horizontal CCD 107 has a potential below the electrode to which the drive signal φHL is input (the electrode in which the impurity concentration just below the two electrodes is not changed) at the output end. Accumulated in the wells. Further, at time t1, since the reset signal φR becomes high, the floating diffusion (FDA) is reset to the voltage of the reset drain (RD).

  Since the potential difference between the drive signals φH1 and φH2 is smaller than that of the prior art, the potential well below the electrode to which the drive signals φH1 and φH2 are input becomes shallow (see FIG. 10 and FIG. 3 for comparison). However, since the potential difference of the drive signal φHL is the same as in the prior art, the potential well below the electrode to which the drive signal φHL is input has the same depth as in the prior art. Therefore, the postponement phenomenon does not occur. Further, since the potential difference of the reset signal φR is the same as the conventional one, the signal charge accumulated in the floating diffusion is appropriately reset. Therefore, the saturation signal amount does not decrease.

  At time t2, drive signals φH1 and φHL are high, drive signal φH2 is low, and reset signal φR is low. At this time, as shown in FIG. 3, preparations for storing signal charges in the floating diffusion (FDA) are completed.

  At time t3, drive signals φH1 and φHL become low, and drive signal φH2 becomes high. At this time, as shown in FIG. 3, the signal charge below the electrode to which the drive signal φH1 is input moves toward the potential well below the electrode to which the drive signal φH2 is input. In addition, the signal charge under the electrode to which the drive signal φHL is input moves toward the potential well under the floating diffusion (FDA).

  As shown in FIG. 3, since the relative relationship between the potential wells under the electrodes to which the drive signals φH1 and φH2 are input is such that two-phase transfer is appropriately performed, the drive signals φH1 and φH2 Even if the potential difference is lowered, the signal charge is appropriately transferred.

  At time t4, the signal charge transferred to the floating diffusion (FDA) is converted into a voltage and output as an output signal.

  Thereafter, the input of the drive signals φH1, φH2, and φHL and the reset signal φR is repeated, whereby the horizontal CCD 107 transfers signal charges.

  Thus, according to the first embodiment, the solid-state imaging device 100 lowers the voltages φH1 and φH2 among the drive signals input from the horizontal driver circuit 103 to the horizontal CCD, while the drive signal φHL and the reset signal are reset. The voltage of signal φR is maintained at a conventional level. As a result, it is possible to prevent the advance phenomenon due to the voltage drop of the drive signal φHL and the decrease of the saturation signal amount due to the voltage drop of the reset signal φR, and reduce the power consumption by lowering the voltage of the drive signals φH1 and φH2. Can do. Therefore, a solid-state imaging device capable of reducing power consumption without reducing the saturation signal amount is provided.

  In the above embodiment, the potential difference between the previous horizontal drive signals (φH1, φH2) is greater than the potential difference between the vertical drive signals (φV1 to φV4), the final horizontal drive signal (φHL), and the reset signal (φR). It was small. However, if the potential difference between the preceding horizontal drive signals (φH1, φH2) is smaller than at least one of the potential difference among the vertical drive signals (φV1 to φV4), the final stage horizontal drive signal (φHL), and the reset signal (φR). Thus, an effect of reducing power consumption can be obtained. Also in this case, naturally, the saturation signal amount can be prevented from being reduced by maintaining the voltages of the drive signal φHL and the reset signal φR at the conventional levels. That is, the potential difference between the previous horizontal drive signals (φH1 and φH2) does not necessarily need to be smaller than all the potential differences among the vertical drive signals (φV1 to φV4), the final horizontal drive signal (φHL), and the reset signal (φR). If the potential difference is smaller than at least one of the potential differences, an effect can be obtained.

  Note that the final stage electrode unit 107 a only needs to be configured to include at least the final electrode 107 b at the output end of the horizontal CCD unit 107. In other words, in the first embodiment, the final electrode portion 107a may include only the final electrode 107b. In this case, it is preferable that a final horizontal drive signal having a higher potential difference than the previous horizontal drive signal is input only to the final electrode 107b. Conversely, the final electrode portion 107a may include other electrodes in addition to the final electrode 107b and the electrode 107c. In this case, the other electrodes are synchronized with the drive signals φH1 and φH2, but a drive signal having a larger potential difference than the previous horizontal drive signal is preferably input.

  The horizontal CCD unit 107 may include a plurality of horizontal CCDs. In this case, it is preferable that a final horizontal drive signal having a potential difference larger than the previous horizontal drive signal is input to the final electrode portion including at least the final electrode at the output terminal of each horizontal CCD.

(Second Embodiment)
In the second embodiment, the configuration of the solid-state imaging device is the same as in the case of the first embodiment, and FIG. In the second embodiment, the phase of the drive signal φHL is advanced by a predetermined time ta as compared with the drive signal φH1. FIG. 4 is a timing chart of drive signals φH1, φH2, and φHL, a reset signal φR, and an output signal in the solid-state imaging device according to the second embodiment.

  The drive signal φHL is a signal (final electrode drive signal) input to the final electrode 107b. The drive signals φH1 and φH2 include a first previous-stage horizontal drive signal φH1 and a second previous-stage horizontal drive signal φH2.

  As shown in FIG. 4, the phase of drive signal φHL is advanced by time ta compared to drive signal φH1. That is, the drive signal φHL rises earlier than the rise timing of the drive signal φH1, and falls earlier than the fall timing of the drive signal φH1. The potential difference between drive signal φH1 and drive signal φH2 is smaller than the potential difference between drive signal φHL and reset signal φR. The drive signals φH1 and φH2 have the same amplitude and opposite phase. The reset signal φR rises at the same timing as the drive signal φH1 rises.

  The drive signal φHL falls at time t5, which is earlier by the time ta than the timing when the drive signal φH1 falls. Therefore, the signal charge under the electrode to which the drive signal φHL is input moves to the floating diffusion at an earlier timing than conventional. Therefore, the signal time becomes longer than in the prior art. Accordingly, the amount of integrated signal increases. As a result, a solid-state imaging device capable of increasing the integrated signal amount and reducing the power consumption without reducing the saturation signal amount is provided.

  The timing at which the drive signal φHL rises may be delayed from the timing at which the drive signal φH1 rises, and the timing at which the drive signal φHL falls may be delayed from the timing at which the drive signal φH1 falls. FIG. 5 is a timing chart when the rise timing of the drive signal φHL is delayed by tc from the rise timing of the drive signal φH1, and the fall timing of the drive signal φHL is delayed by tc from the fall timing of the drive signal φH1. By doing in this way, as shown in FIG. 5, the feedthrough period which shows a reference voltage becomes long. Therefore, noise can be reduced.

  As described above, by increasing the phase of the final horizontal drive signal and the previous horizontal drive signal, it is possible to obtain an effect of increasing the integrated signal amount and a noise reduction effect.

(Third embodiment)
In the third embodiment, the configuration of the solid-state imaging device is the same as in the case of the first embodiment, and FIG. In the third embodiment, the rise time of the reset signal is delayed by a predetermined time tb compared to the rise time of the drive signal φH1. FIG. 6 is a timing chart of drive signals φH1, φH2, and φHL, a reset signal φR, and an output signal in the solid-state imaging device according to the third embodiment.

  As shown in FIG. 6, the rise time of the reset signal φR is delayed by the time tb compared to the rise time of the drive signal φH1. That is, the reset signal φR rises later than the rising timing of the drive signal φH1. The potential difference between drive signal φH1 and drive signal φH2 is smaller than the potential difference between drive signal φHL and reset signal φR. The drive signals φH1 and φHL have the same amplitude and phase.

  The reset signal φR rises at time t6, which is a time tb later than the timing when the drive signal φH1 rises. Therefore, the signal charge accumulated in the floating diffusion is reset at a later timing than in the prior art. Accordingly, the amount of integrated signal increases. As a result, a solid-state imaging device capable of increasing the integrated signal amount and reducing the power consumption without reducing the saturation signal amount is provided.

  The reset signal φR may rise earlier than the drive signal φH1. FIG. 7 is a timing chart when the reset signal φR rises earlier by td than the drive signal φH1. By doing in this way, as shown in FIG. 7, the feedthrough period which shows a reference voltage becomes long. Therefore, noise can be reduced.

(Fourth embodiment)
In the first embodiment, the voltage of the drive signal φHL inputted to the two electrodes at the output terminal of the horizontal CCD is kept high, and the voltages of the drive signals φH1 and φH2 inputted to the other electrodes are made low. It was decided to. In the fourth embodiment, a solid-state imaging device is described in which among the drive signals φH1 and φH2, the voltages of the drive signals φH1 and φH2 input to some electrodes on the horizontal CCD side are kept high.

  FIG. 8 is a diagram showing a part of a schematic configuration of a solid-state imaging device 400 according to the fourth embodiment of the present invention. In FIG. 8, a horizontal CCD unit 407, a vertical CCD 106, an output unit 408, a vertical horizontal driver circuit 402, and a horizontal driver circuit 403 of the solid-state imaging device 400 are illustrated. The configuration not shown is the same as that of the first embodiment.

  The horizontal CCD unit 407 includes electrodes 4073 and 4074 that accumulate signal charges transferred from the vertical CCD 106, and electrodes 4072, 4071, and 4070 that taper toward the floating diffusion 410 in the output unit 408. The electrodes 4072, 4071, and 4070 constitute a final electrode portion. The widths W1 of the electrodes 4073 and 4074 are constant. The electrode 4072 includes an electrode having a width W2 and an electrode having a width W3. The electrode 4071 includes an electrode having a width W4 and an electrode having a width W5. The electrode 4070 includes an electrode having a width W6 and an electrode having a width W7 (final electrode). The relationship of W1 <W2 <W3 <W4 <W5 <W6 <W7 is established. Thus, as the electrode approaches the floating diffusion 410, the width of the electrode increases.

  The electrode 4073 receives a drive signal (first front horizontal drive signal) φH1b. The electrode 4074 receives a drive signal (second previous-stage horizontal drive signal) φH2b. The drive signals φH1b and φH2b are set to have a low potential difference and are output from the horizontal driver circuit 403.

  The electrode 4072 receives a drive signal (middle stage electrode drive signal) φH2a. The electrode 4071 receives a drive signal (middle electrode drive signal) φH1a. A drive signal (final electrode drive signal) φHL is input to the electrode 4070. The final horizontal drive signal for driving the final electrode unit 4075 includes a middle electrode drive signal and a final electrode drive signal. The final electrode portion 4075 is wired separately from the horizontal CCD electrodes (4073, 4074) other than the electrodes (4070, 4071, and 4072) of the final electrode portion 4075 in the horizontal CCD portion 407. The drive signals φH2a, φH1a, and φHL have a high potential difference and are output from the vertical / horizontal driver circuit 402. Since the horizontal CCD unit 407 has a structure that tapers as it approaches the floating diffusion 410, signal charges are likely to accumulate in the floating diffusion 410. As the electrodes 4072, 4071, and 4070 approach the floating diffusion 410, the length in the vertical direction decreases while the width increases. Therefore, if a low-voltage drive signal is input, a well having a sufficient depth cannot be formed. Therefore, in this embodiment, a high voltage drive signal is input to the tapered electrodes 4072, 4071, and 4070.

  The output unit 408 includes an output gate 409, a floating diffusion 410, a reset gate 411, and a reset drain 412. The reset signal φR from the vertical and horizontal driver circuit 402 is input to the reset gate 411.

  FIG. 9 is a timing chart of drive signals φH1a, φH2a, φH1b, φH2b, and φHL, a reset signal φR, and an output signal in the solid-state imaging device 400. As shown in FIG. 9, the drive signals φH1a and φHL have the same amplitude and phase. The drive signals φH1a and φH2a have the same amplitude and opposite phase. The drive signals φH1b and φH2b have the same amplitude and opposite phase. The potential difference between drive signals φH1b and φH2b is smaller than the potential difference between drive signals φH1a, φH2a, and φHL, and reset signal φR. At the timing when drive signal φH1b rises, reset signal φR and drive signals φHL and φH1a rise. At the timing when the drive signal φH2b rises, the drive signal φH2a rises.

  The drive signals φH1b and φH1a change at the same timing except that the amplitudes are different. The drive signals φH2b and φH2b change at the same timing except that the amplitudes are different. That is, drive signals φH1a and φH2a are synchronized with drive signals φH1b and φH2b. In addition, since the potential difference between drive signals φH1a and φH2a is large, a well having a sufficiently deep potential is formed. Therefore, the signal charges are appropriately transferred by the electrodes 4074, 4073, 4072, and 4071 in the horizontal CCD unit 407.

  Since the potential difference of the drive signal φHL input to the electrode 4070 is maintained at the same level as in the prior art, the advance phenomenon does not occur. Further, since the potential difference of the reset signal φR is maintained at the same level as the conventional one, the saturation signal amount is not reduced.

  Thereby, a solid-state imaging device capable of reducing power consumption without reducing the saturation signal amount is provided.

  Also in the fourth embodiment, as in the first embodiment, the potential difference between the drive signals φH1b and φH2b should be smaller than at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal. Thus, the effect of reducing power consumption can be obtained. Of course, in order to prevent the amount of saturation signal from being reduced, it is preferable to maintain the conventional level of the potential difference between the final stage horizontal drive signal and the reset signal.

  Note that the solid-state imaging device according to the fourth embodiment may be driven with the phase of the drive signal φHL advanced as in the second embodiment, or may be driven with the phase of the drive signal φHL delayed. Alternatively, as in the third embodiment, the phase of the reset signal may be delayed and driven, or the phase of the reset signal may be advanced. Thereby, the same effect as the second or third embodiment can be obtained.

  Note that the vertical and horizontal driver circuits and horizontal driver circuits shown in the first to fourth embodiments can be provided as driver ICs for outputting the signals as described above and inputting them to the solid-state imaging device.

  Further, by using the solid-state imaging device driving methods shown in the first to fourth embodiments, the solid-state imaging device can be driven so that the power consumption is reduced without reducing the saturation signal amount.

  The solid-state imaging device of the present invention can reduce power consumption without reducing the saturation signal amount, and is useful for cameras and the like.

1 is a diagram showing a schematic configuration of a solid-state imaging device 100 according to a first embodiment of the present invention. Timing chart of drive signals φH1, φH2, and φHL, reset signal φR, and output signal in solid-state imaging device 100 Sectional drawing in AB line of the horizontal CCD part 107 shown in FIG. 1 and the output part 108, and the figure which shows electric potential distribution Timing chart of drive signals φH1, φH2, and φHL, reset signal φR, and output signal in the solid-state imaging device according to the second embodiment Timing chart when the rise timing of the drive signal φHL is delayed from the rise timing of the drive signal φH1, and the fall timing of the drive signal φHL is delayed from the fall timing of the drive signal φH1 Timing chart of drive signals φH1, φH2, and φHL, reset signal φR, and output signal in the solid-state imaging device according to the third embodiment Timing chart when reset signal φR rises earlier than drive signal φH1 The figure which shows a part of schematic structure of the solid-state imaging device 400 concerning the 4th Embodiment of this invention. Timing chart of drive signals φH1a, φH2a, φH1b, φH2b, and φHL, reset signal φR, and output signal in solid-state imaging device 400 The figure which shows schematic structure of the conventional solid-state imaging device 900. Timing chart of drive signals φH1, φH2, and φHL, reset signal φR, and output signal in conventional solid-state imaging device 900 Sectional drawing in AB line of the horizontal CCD907 and the output part 908 shown in FIG. 8, and the figure which shows electric potential distribution The figure for demonstrating the fall of the saturation signal amount by the voltage fall of the reset signal (phi) R. Illustration for explaining the postponement phenomenon A diagram for explaining the increase in illuminance caused by the postponement phenomenon

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,400 Solid-state imaging device 101 Solid-state image sensor 102,402 Vertical horizontal driver circuit 103,403 Horizontal driver circuit 104 Output amplifier 105 Photoelectric conversion element 106 Vertical CCD
107,407 Horizontal CCD unit 107a, 4075 Final electrode unit 107b, 4070 Final electrode 107c, 4071, 4072, 4073, 4074 Electrode 108, 408 Output unit 109, 409 Output gate 110, 410 Floating diffusion 111, 411 Reset gate 112, 412 Reset drain

Claims (11)

A solid-state imaging device,
A photoelectric conversion element section that generates a signal charge according to the intensity of incident light;
A vertical CCD (Charge Coupled Device) unit for transferring the signal charges generated by the photoelectric conversion element unit in a vertical direction;
A horizontal CCD unit for transferring the signal charges transferred by the vertical CCD unit in a horizontal direction;
An output unit connected to an output terminal of the horizontal CCD unit, which converts the signal charge transferred in the horizontal direction into a voltage and outputs the voltage;
A vertical drive signal for driving the vertical CCD unit, a final stage horizontal drive signal for inputting to a final stage electrode unit including at least a final electrode at an output terminal of the horizontal CCD unit, and an input to a reset gate in the output unit A vertical and horizontal driver circuit that outputs a reset signal for
A horizontal driver circuit for inputting a previous-stage horizontal drive signal to electrodes in the horizontal CCD unit other than the electrodes included in the final-stage electrode unit;
The final stage electrode part is wired separately from the horizontal CCD electrode other than the final stage electrode part,
The solid-state imaging device, wherein a potential difference of the preceding horizontal drive signal is smaller than at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal.   The solid-state imaging device according to claim 1, wherein the final stage horizontal drive signal and the previous stage horizontal drive signal have different phases. The front horizontal drive signal includes a first front horizontal drive signal and a second front horizontal drive signal for two-phase driving,
Of the final stage horizontal drive signal, the final electrode drive signal input to the final electrode rises earlier than the rise timing of the first previous horizontal drive signal, and the fall timing of the first previous horizontal drive signal. The solid-state imaging device according to claim 2, wherein the solid-state imaging device falls earlier. The front horizontal drive signal includes a first front horizontal drive signal and a second front horizontal drive signal for two-phase driving,
Of the final horizontal drive signal, the final electrode drive signal input to the final electrode rises later than the rise timing of the first previous horizontal drive signal, and the fall timing of the first previous horizontal drive signal. The solid-state imaging device according to claim 2, wherein the solid-state imaging device falls later. The front horizontal drive signal includes a first front horizontal drive signal and a second front horizontal drive signal for two-phase driving,
2. The solid-state imaging device according to claim 1, wherein the reset signal rises later than a rise timing of the first front-stage horizontal drive signal. The front horizontal drive signal includes a first front horizontal drive signal and a second front horizontal drive signal for two-phase driving,
The solid-state imaging device according to claim 1, wherein the reset signal rises earlier than a rise timing of the first front-stage horizontal drive signal. The final electrode portion is tapered toward the floating diffusion in the output portion,
The final horizontal drive signal consists of a final electrode drive signal for driving the final electrode and a middle electrode drive signal for driving an electrode other than the final electrode,
The middle electrode drive signal is synchronized with the previous horizontal drive signal,
The solid-state imaging device according to claim 1, wherein a potential difference of the middle-stage electrode drive signal is larger than a potential difference of the previous-stage horizontal drive signal. A solid-state imaging device,
A photoelectric conversion element section that generates a signal charge according to the intensity of incident light;
A vertical CCD (Charge Coupled Device) unit for transferring the signal charges generated by the photoelectric conversion element unit in a vertical direction;
A horizontal CCD unit for transferring the signal charges transferred by the vertical CCD unit in a horizontal direction;
An output unit connected to an output end of the horizontal CCD unit, and converting the signal charge transferred in the horizontal direction into a voltage and outputting the voltage;
The vertical CCD unit receives a vertical drive signal for transferring signal charges in the vertical direction,
The final stage electrode part including at least the final electrode at the output end of the horizontal CCD part is wired separately and independently from the horizontal CCD electrode other than the final stage electrode part,
The final stage electrode unit receives a final stage horizontal drive signal for transferring signal charges accumulated under the final stage electrode unit.
A reset signal is input to the reset gate in the output unit,
To the electrodes in the horizontal CCD unit other than the electrodes included in the final electrode unit, a previous horizontal drive signal for transferring signal charges accumulated under the electrodes is input,
A solid-state imaging device, wherein a potential difference of the preceding horizontal drive signal is smaller than at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal. A photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD (Charge Coupled Device) unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and the vertical CCD A horizontal CCD unit that horizontally transfers the signal charges transferred by the unit, and an output unit that is connected to an output terminal of the horizontal CCD unit and converts the signal charges transferred in the horizontal direction into a voltage and outputs the voltage. A method for driving a solid-state imaging device comprising:
A vertical drive signal for transferring a signal charge in the vertical direction is input to the vertical CCD unit,
At least the final electrode at the output end of the horizontal CCD unit is stored under the final electrode unit in the final electrode unit that is wired separately and independently from the horizontal CCD electrode other than the final electrode unit. The final stage horizontal drive signal for transferring the signal charge
A reset signal is input to the reset gate in the output unit,
A front-stage horizontal drive signal for transferring signal charges accumulated under the electrodes is input to the electrodes in the horizontal CCD unit other than the electrodes included in the final-stage electrode unit,
The solid-state imaging device driving method, wherein a potential difference of the front-stage horizontal drive signal is smaller than at least one of the vertical drive signal, the final-stage horizontal drive signal, and the reset signal. A photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD (Charge Coupled Device) unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and the vertical CCD A horizontal CCD unit that horizontally transfers the signal charges transferred by the unit, and an output unit that is connected to an output terminal of the horizontal CCD unit and converts the signal charges transferred in the horizontal direction into a voltage and outputs the voltage. A driver IC for driving a solid-state imaging device comprising:
The driver IC is
A vertical drive signal for transferring a signal charge in the vertical direction is input to the vertical CCD unit,
At least the final electrode at the output end of the horizontal CCD unit is stored under the final electrode unit in the final electrode unit that is wired separately and independently from the horizontal CCD electrode other than the final electrode unit. The final stage horizontal drive signal for transferring the signal charge
A reset signal is input to the reset gate in the output unit,
A potential difference of at least one of the vertical drive signal, the final-stage horizontal drive signal, and the reset signal is a previous-stage horizontal drive signal that is input to an electrode in the horizontal CCD unit other than the electrode included in the final-stage electrode unit. A driver IC characterized by being larger than the potential difference. A photoelectric conversion element unit that generates a signal charge according to the intensity of incident light, a vertical CCD (Charge Coupled Device) unit that transfers the signal charge generated by the photoelectric conversion element unit in a vertical direction, and the vertical CCD A horizontal CCD unit that horizontally transfers the signal charges transferred by the unit, and an output unit that is connected to an output terminal of the horizontal CCD unit and converts the signal charges transferred in the horizontal direction into a voltage and outputs the voltage. A driver IC for driving a solid-state imaging device comprising:
The vertical CCD unit receives a vertical drive signal for transferring signal charges in the vertical direction,
The final stage electrode unit including at least the final electrode at the output end of the horizontal CCD unit and wired separately from the horizontal CCD electrode other than the final stage electrode unit is stored below the final stage electrode unit. The final horizontal drive signal for transferring the signal charge to be transferred is input,
A reset signal is input to the reset gate in the output unit,
The driver IC inputs, to the electrodes in the horizontal CCD unit other than the electrodes included in the final-stage electrode unit, a previous-stage horizontal drive signal for transferring signal charges accumulated under the electrodes,
The driver IC, wherein a potential difference of the previous horizontal drive signal is smaller than at least one of the vertical drive signal, the final horizontal drive signal, and the reset signal.

Images