Camera device and electronic equipment including the same

Abstract

The present invention provides an imaging device and an electronic device including the imaging device, which include: a first photoelectric conversion region, which photoelectrically converts incident light into electric charge and accumulates the electric charge; a second photoelectric conversion region, which photoelectrically converts incident light into electric charge, and the area of the first photoelectric conversion region is larger than the area of the second photoelectric conversion region; a floating diffusion region, which accumulates the electric charge photoelectrically converted by the first and second photoelectric conversion regions to convert the electric charge into voltage; a first charge transfer transistor, which transfers the electric charge accumulated in the first photoelectric conversion region to the floating diffusion region; a second charge transfer transistor, which transfers the electric charge accumulated in the second photoelectric conversion region to the floating diffusion region; a charge reset transistor, which resets the electric charge accumulated in the floating diffusion region; a first discharge transistor, which releases the electric charge accumulated in the first photoelectric conversion region; and a second discharge transistor, which releases the electric charge accumulated in the second photoelectric conversion region.

Description

[0001] This application is a divisional application of a patent application with an application date of December 12, 2017, an invention name of “Solid-state imaging device, driving method of solid-state imaging device and electronic device” and an application number of 201780088009.4. Technical Field

[0002] The present technology relates to a solid-state imaging device, and more particularly to a solid-state imaging device that reduces signal variation under high illuminance exceeding a saturation level, a method for driving the solid-state imaging device, and an electronic device. Background Art

[0003] In a typical metal oxide semiconductor (MOS) type image sensor (which reads the charge accumulated in the photoelectric conversion unit according to the amount of incident light through a MOS transistor), its saturation level is limited according to the amount of charge that can be accumulated in the photoelectric conversion unit. In other words, the amount of light cannot be correctly detected within a range exceeding the saturation level of the photoelectric conversion unit. Therefore, the following operation is conventionally used, in which the charge accumulated in the photoelectric conversion unit is caused to overflow from the transfer gate to the charge-voltage conversion unit, the charge reset unit, and the drain power supply, and the voltage of the charge-voltage conversion unit at this time is detected as a signal voltage (hereinafter referred to as logarithmic reading). The voltage detected at this time is a signal corresponding to the logarithm of the amount of incident light. With this configuration, it is also possible to detect the amount of light exceeding the saturation level.

[0004] When performing this logarithmic reading along with normal reading by accumulation (hereinafter referred to as linear reading), there is a problem in that the timing of switching from linear reading to logarithmic reading varies from pixel to pixel. This is because the saturation level of the photoelectric conversion unit and the thresholds of the transistors in the transfer gate and charge reset unit, which determine the level at which overflow begins, vary from pixel to pixel. Therefore, in conventional technology, before acquiring the signal for logarithmic reading, charge is injected from the drain power supply into the photoelectric conversion unit and charge-voltage conversion unit until it reaches the saturation level, and then the charge reset unit is reset to an intermediate level between the high and low levels. This reduces the variation in the charge reset unit and reduces the variation in the charge-voltage conversion unit between pixels. In addition, in this case, the transfer gate is turned on to transfer the signal (saturation level) from the photoelectric conversion unit to the charge-voltage conversion unit and start light reception, reducing the variation in the photoelectric conversion unit and transfer gate between pixels. When reading noise, the transfer gate is turned on, where the photoelectric conversion unit and charge-voltage conversion unit are filled with charge, and the charge reset unit is reset to an intermediate level again, and the charge accumulated in the charge-voltage conversion unit is read out. These operations reduce differences between pixels and reduce variations in the timing of switching from linear reading to logarithmic reading (for example, see Patent Document 1).

[0005] Reference List

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-060658 Summary of the Invention

[0008] Problems to be solved by the present invention

[0009] In the conventional technology described above, when linear and logarithmic reading are performed within a single pixel, the difference between pixels is reduced, and the difference in the switching time from linear to logarithmic reading is also reduced. In this regard, when reading light at high illumination levels using logarithmic reading, charge must overflow from the photoelectric conversion unit to the drain power supply. Therefore, a small photoelectric conversion unit is advantageous. On the other hand, when the size of the photoelectric conversion unit is reduced, the sensitivity is insufficient to read light at low illumination levels using linear reading. Furthermore, in the conventional technology described above, during the operation to reduce the difference, the photoelectric conversion unit also receives light during read noise. In the case of high illumination, there is a possibility that charge overflows from the transfer gate and mixes into the charge-voltage conversion unit immediately after resetting to an intermediate level.

[0010] The present technology has been made in view of the above-described circumstances, and an object of the present technology is to reduce variations in the switching timing from linear reading to logarithmic reading and to perform reading with high precision in a solid-state imaging device.

[0011] Solutions to the Problem

[0012] The present technology has been proposed to solve the above-mentioned problems. A first aspect of the present technology is a solid-state imaging device and a method for driving the solid-state imaging device. The solid-state imaging device includes: a first photoelectric conversion unit configured to photoelectrically convert incident light into electric charge and accumulate the electric charge in a first region; a second photoelectric conversion unit configured to photoelectrically convert incident light into electric charge and accumulate the electric charge in a second region, the second region having an area smaller than that of the first region; a charge-voltage conversion unit configured to accumulate electric charge photoelectrically converted by the first and second photoelectric conversion units and convert the electric charge into a voltage; a first charge transfer unit configured to transfer the electric charge accumulated in the first photoelectric conversion unit to the charge-voltage conversion unit; a second charge transfer unit configured to transfer the electric charge accumulated in the second photoelectric conversion unit to the charge-voltage conversion unit; a charge reset unit configured to reset the electric charge accumulated in the charge-voltage conversion unit; and a first discharge unit configured to discharge the electric charge accumulated in the first photoelectric conversion unit. This configuration produces the following effect: preventing unnecessary electric charge from being mixed into the first photoelectric conversion unit.

[0013] Furthermore, in the first aspect, the solid-state imaging device may further include a driving unit configured to drive the first photoelectric conversion unit so that the first discharge unit discharges the charge accumulated in the first photoelectric conversion unit, while controlling the potential of the drain of the charge reset unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, and then exposing the second photoelectric conversion unit. This configuration prevents unnecessary charge from being mixed into the first photoelectric conversion unit by discharging the charge accumulated in the first photoelectric conversion unit when the second photoelectric conversion unit performs logarithmic reading.

[0014] Furthermore, in the first aspect, the solid-state imaging device may further include a second discharge unit configured to discharge charge accumulated in the second photoelectric conversion unit, and the drive unit may drive the device in such a manner that: the drive unit causes the first discharge unit to discharge the charge accumulated in the first photoelectric conversion unit while controlling the potential of the drain of the charge reset unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level; the drive unit then causes the second discharge unit to discharge the charge accumulated in the second photoelectric conversion unit while applying an intermediate potential to the charge reset unit to accumulate charge in the charge-voltage conversion unit; the drive unit also causes the charge reset unit to be non-conductive, transfers the charge accumulated in the charge-voltage conversion unit to the charge-voltage conversion unit, and then exposes the second photoelectric conversion unit. This configuration prevents unnecessary charge from being mixed into the charge-voltage conversion unit by discharging the charge accumulated in the second photoelectric conversion unit during a reset operation using the intermediate potential during logarithmic reading in the second photoelectric conversion unit.

[0015] Furthermore, in the first aspect, the solid-state imaging device may further include a signal amplification unit configured to amplify the charge accumulated in the charge-voltage conversion unit and output a pixel signal having a level corresponding to the charge. Furthermore, the solid-state imaging device may further include a conversion efficiency switching unit configured to switch the capacitance of the charge-voltage conversion unit, thereby switching the degree of amplification in the signal amplification unit. This configuration achieves the following effect: by switching the capacitance of the charge-voltage conversion unit for low-illuminance signals, sufficient resolution is achieved.

[0016] In addition, a second aspect of the present technology is an electronic device, which includes: a first photoelectric conversion unit, which is configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in a first region; a second photoelectric conversion unit, which is configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in a second region, the area of the second region being smaller than the area of the first region; a charge-voltage conversion unit, which is configured to accumulate electric charges photoelectrically converted by the first photoelectric conversion unit and the second photoelectric conversion unit to convert the electric charges into voltage; a first charge transfer unit, which is configured to transfer the electric charges accumulated in the first photoelectric conversion unit to the charge-voltage conversion unit; and a second A charge transfer unit configured to transfer charge accumulated in the second photoelectric conversion unit to the charge-voltage conversion unit; a charge reset unit configured to reset the charge accumulated in the charge-voltage conversion unit; a first discharge unit configured to discharge the charge accumulated in the first photoelectric conversion unit; and a drive unit configured to drive the first discharge unit to discharge the charge accumulated in the first photoelectric conversion unit while controlling the potential of the drain of the charge reset unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, and then expose the second photoelectric conversion unit. This configuration prevents unnecessary charge from being mixed into the first photoelectric conversion unit by discharging the charge accumulated in the first photoelectric conversion unit during logarithmic reading of the second photoelectric conversion unit.

[0017] Effects of the present invention

[0018] This technology can achieve the following excellent effects: it can reduce the variation in the switching timing from linear reading to logarithmic reading and perform reading with high precision in a solid-state imaging device. Note that the effects of this technology are not limited to the effects described here and can be any effect described in this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a diagram illustrating an exemplary configuration of a solid-state imaging device 10 in an embodiment of the present technology.

[0020] Figure 2 is a diagram showing an exemplary circuit configuration for explaining the operation of each pixel of the pixel array unit 100 in the embodiment of the present technology.

[0021] Figure 3 is a diagram showing an example of the light response characteristic of each pixel of the pixel array unit 100 in the embodiment of the present technology.

[0022] Figure 4is a diagram illustrating an example of the read timing of each pixel of the pixel array unit 100 in the embodiment of the present technology.

[0023] Figure 5 It shows the corresponding Figure 4 Figure 2 shows an exemplary potential diagram under high illumination.

[0024] Figure 6 It shows the corresponding Figure 4 Figure 2 shows an exemplary potential diagram under low illumination.

[0025] Figure 7 is a diagram illustrating an exemplary operation of the discharge unit 180 in each pixel of the pixel array unit 100 in the embodiment of the present technology.

[0026] Figure 8 is a diagram illustrating an exemplary configuration of each pixel of the pixel array unit 100 in the first embodiment of the present technology.

[0027] Figure 9 is a diagram illustrating an exemplary configuration of each pixel of the pixel array unit 100 in a modification example of the first embodiment of the present technology.

[0028] Figure 10 is a diagram illustrating an exemplary configuration of each pixel of the pixel array unit 100 in the second embodiment of the present technology.

[0029] Figure 11 is a diagram illustrating exemplary potentials in an operating state of the second embodiment of the present technology.

[0030] Figure 12 is a diagram showing an example of the light response characteristic of each pixel of the pixel array unit 100 in the second embodiment of the present technology.

[0031] Figure 13 is a diagram showing an example of the read timing of each pixel of the pixel array unit 100 in the second embodiment of the present technology. DETAILED DESCRIPTION

[0032] Hereinafter, a mode for implementing the present technology (hereinafter referred to as an embodiment) will be described. The description will be made in the following order.

[0033] 1. First Embodiment (Example of Providing a Discharge Unit in a Photoelectric Conversion Unit)

[0034] 2. Second Embodiment (Example in which a Charge-Voltage Control Unit is Provided Between Pixels)

[0035] <1. First embodiment>

[0036] [Structure of Solid-State Image Capture Device]

[0037] Figure 1 This figure illustrates an exemplary configuration of a solid-state imaging device 10 in an embodiment of the present technology. For example, the solid-state imaging device 10 includes a MOS image sensor and acquires images by photoelectrically converting incident light and generating image signals. The solid-state imaging device 10 includes a pixel array unit 100, a vertical drive unit 220, a column processing unit 230, a horizontal drive unit 240, a system control unit 250, a signal processing unit 280, and a data storage unit 290.

[0038] The pixel array unit 100 includes pixels, each of which includes a photoelectric conversion unit that generates and accumulates charge according to the amount of light incident from a subject, and the pixels are arranged two-dimensionally in the horizontal (row) direction and the vertical (column) direction. In the pixel array unit 100, a pixel drive line 229 is arranged in the row direction for each pixel row (which includes pixels arranged in the row direction), and a vertical signal line (VSL) 239 is arranged in the column direction for each pixel column (which includes pixels arranged in the column direction).

[0039] The vertical drive unit 220 includes a shift register, an address decoder, and other components. It supplies signals and other components to the pixels via a plurality of pixel drive lines 229, driving the pixels of the pixel array unit 100. The vertical drive unit 220 includes a selection control unit 221, a reset control unit 222, a transfer control unit 223, a reset drain control unit 224, and a discharge control unit 225. The selection control unit 221 controls a selection signal SEL applied to a pixel selection unit (described later). The reset control unit 222 controls a reset signal RST applied to a charge reset unit (described later). The transfer control unit 223 controls a transfer signal TRG applied to a charge transfer unit (described later). The reset drain control unit 224 controls the potential of the reset drain of the charge reset unit (described later). The discharge control unit 225 controls a discharge signal OFG applied to a discharge unit (described later). Note that the vertical drive unit 220 is an example of a drive unit described in the claims.

[0040] For each pixel column of the pixel array unit 100 , the column processing unit 230 reads signals from each pixel through the vertical signal line 239 and performs noise reduction processing, correlated double sampling processing, and analog-to-digital (AD) conversion processing, thereby generating a pixel signal.

[0041] The horizontal driving unit 240 includes a shift register, an address decoder, and the like, and sequentially selects unit circuits corresponding to pixel columns of the column processing unit 230. By performing selective scanning by the horizontal driving unit 240, pixel signals that have been signal-processed in each unit circuit of the column processing unit 230 are sequentially output to the signal processing unit 280.

[0042] The system control unit 250 includes a timing generator that generates various driving signals and the like, and controls driving of the vertical driving unit 220 , the column processing unit 230 , and the horizontal driving unit 240 based on the driving signals generated by the timing generator.

[0043] The signal processing unit 280 performs signal processing (for example, arithmetic processing, etc.) on each pixel signal supplied from the column processing unit 230 , and outputs an image signal based on the pixel signal.

[0044] The data storage unit 290 stores therein the image signal processed by the signal processing unit 280 .

[0045] [Circuit structure]

[0046] Figure 2 is a diagram showing an exemplary circuit configuration for explaining the operation of each pixel of the pixel array unit 100 in an embodiment of the present technology. Hereinafter, before explaining the configuration of each pixel of the pixel array unit 100, the basic configuration serving as a premise will be described. First, it is assumed that each pixel of the pixel array unit 100 includes a photoelectric conversion unit 110, a charge transfer unit 120, a charge-voltage conversion unit 130, a charge reset unit 140, a signal amplification unit 150, a pixel selection unit 160, a constant current source 170, and a discharge unit 180.

[0047] The photoelectric conversion unit 110 includes a PN junction photodiode (PD: photodiode), and generates and accumulates charges according to the amount of incident light.

[0048] The charge transfer unit 120 transfers the charge accumulated in the photoelectric conversion unit 110 to the charge-voltage conversion unit 130 according to the transfer signal TRG. When the transfer signal TRG applied to the charge transfer unit 120 transitions to an H level, the charge transfer unit 120 enters a conductive state, and the charge accumulated in the photoelectric conversion unit 110 is transferred to the charge-voltage conversion unit 130. Note that the charge transfer unit 120 includes, for example, a depletion transistor and forms an overflow path that transfers some charge even when the charge transfer unit 120 is in a non-conductive state. Therefore, when the photoelectric conversion unit 110 becomes saturated, the charge overflowing from the photoelectric conversion unit 110 is transferred to the charge-voltage conversion unit 130 through the overflow path.

[0049] The charge-voltage conversion unit 130 is a floating diffusion (FD) capacitor formed between the drain of the charge transfer unit 120 and the source of the charge reset unit 140. The charge-voltage conversion unit 130 accumulates the charge transferred from the charge transfer unit 120.

[0050] The charge reset unit 140 resets the charge accumulated in the charge-voltage conversion unit 130 according to the reset signal RST. When the reset signal RST applied to the charge reset unit 140 transitions to an H level, the charge reset unit 140 enters a conductive state, and the charge reset unit 140 resets the charge accumulated in the charge-voltage conversion unit 130. Furthermore, the charge reset unit 140 includes a depletion-type transistor, etc., and constitutes an overflow path that transfers some charge even when the charge reset unit 140 is in a non-conductive state. Therefore, when the charge-voltage conversion unit 130 becomes saturated, the overflow path enables the charge overflowing from the charge-voltage conversion unit 130 to be transferred to the drain (reset drain) of the charge reset unit 140.

[0051] The signal amplification unit 150 amplifies the charge accumulated in the charge-voltage conversion unit 130 and outputs a pixel signal of a level corresponding to the charge. The signal amplification unit 150 includes a gate connected to the charge-voltage conversion unit 130 and a drain connected to the power supply voltage Vdd. The signal amplification unit 150 serves as an input unit for a reading circuit that reads the charge obtained through photoelectric conversion in the photoelectric conversion unit 110, i.e., a so-called source follower circuit. In other words, the signal amplification unit 150 includes a source connected to the vertical signal line 239 via the pixel selection unit 160. Therefore, the signal amplification unit 150, together with the constant current source 170 connected to one end of the vertical signal line 239, constitutes a source follower circuit.

[0052] The pixel selection unit 160 selects any pixel in the pixel array unit 100. The pixel selection unit 160 is connected between the source of the signal amplification unit 150 and the vertical signal line 239, and a selection signal SEL is supplied to the gate of the pixel selection unit 160. When the selection signal SEL transitions to an H level, the pixel selection unit 160 enters a conductive state, i.e., the pixel is selected. When the pixel is selected, the signal output from the signal amplification unit 150 is read out to the column processing unit 230 via the vertical signal line 239.

[0053] Discharge unit 180 releases the charge accumulated in photoelectric conversion unit 110 in response to overflow gate signal OFG. As previously mentioned, in conventional technology, the photoelectric conversion unit also receives light during read noise reduction operations. Under high illumination conditions, charge may overflow from the transfer gate and enter the charge-voltage conversion unit immediately after resetting to an intermediate level. Therefore, in this embodiment, discharge unit 180 is provided and remains conductive during the reset operation of logarithmic reading to selectively discharge the charge accumulated in photoelectric conversion unit 110 due to light reception.

[0054] [Photoresponse characteristics]

[0055] Figure 3 This diagram shows an example of the light response characteristics of each pixel of pixel array unit 100 in an embodiment of the present technology. When the amount of incident light corresponds to relatively low illuminance, the output signal is a linear signal that is linear with respect to the amount of incident light. As described above, this type of reading at low illuminance is called linear reading.

[0056] On the other hand, when the incident light intensity corresponds to relatively high illuminance, the charge accumulated in the photoelectric conversion unit 110 overflows from the charge transfer unit 120 to the charge-voltage conversion unit 130, the charge reset unit 140, and the reset drain. Therefore, the voltage detected at this time is a logarithmic signal corresponding to the logarithm of the incident light intensity. As described above, this type of reading under high illuminance is called logarithmic reading.

[0057] To reduce variations in the timing of switching from linear reading to logarithmic reading, when reading noise, the charge reset unit 140 is brought to an intermediate level, where the photoelectric conversion unit 110 and the charge-voltage conversion unit 130 are fully charged, and then the charge transfer unit 120 is turned on. Although the charge accumulated in the charge-voltage conversion unit 130 is read as noise in this manner, since the photoelectric conversion unit 110 also receives light during this period, under high illuminance conditions, charge may overflow from the charge transfer unit 120 and mix into the charge-voltage conversion unit 130 immediately after resetting to the intermediate level. Therefore, in this embodiment, the discharge unit 180 is provided and remains turned on during the reset operation of logarithmic reading to selectively discharge the charge accumulated in the photoelectric conversion unit 110 by light reception.

[0058] [Read Timing]

[0059] Figure 4 is a diagram illustrating an example of the read timing of each pixel of the pixel array unit 100 in the embodiment of the present technology. Figure 5 It shows the corresponding Figure 4 Figure 2 shows an exemplary potential diagram under high illumination. Figure 6 It shows the corresponding Figure 4 Note that here, an exemplary operation is shown in the case where the discharge unit 180 is not provided.

[0060] At time ta, the reset drain control unit 224 changes the voltage VRD of the reset drain (which serves as the drain of the charge reset unit 140) from the reset potential Vrst to the voltage Vmid at which the charge in the photoelectric conversion unit 110 is saturated. Therefore, as shown in state Sa, the photoelectric conversion unit 110, the charge transfer unit 120, the charge-voltage conversion unit 130, the charge reset unit 140, and the reset drain are all filled with charge.

[0061] At time tb, the reset drain control unit 224 returns the reset drain voltage VRD to the reset voltage Vrst. At this time, the charge transfer unit 120 and the charge reset unit 140 remain in the non-conductive state. Therefore, as shown in state Sb, the photoelectric conversion unit 110 and the charge-voltage conversion unit 130 reach their respective saturation levels.

[0062] At time tc, the reset control unit 222 applies the intermediate potential to the reset signal RST. In response, the charge reset unit 140 turns on at the intermediate potential. Therefore, as shown in state Sc, the charge accumulated in the charge reset unit 140 at the intermediate potential remains in the charge-voltage conversion unit 130.

[0063] At time td, the reset control unit 222 sets the reset signal RST to an L level. In response, the charge reset unit 140 enters a non-conductive state. Therefore, as shown in state Sd, the charge accumulated in the charge reset unit 140 via the intermediate potential is accumulated in the charge-voltage conversion unit 130.

[0064] At time te, the transfer control unit 223 sets the transfer signal TRG to H level. In response to this, the charge transfer unit 120 enters the on state.

[0065] At time tf, the transfer control unit 223 sets the transfer signal TRG to an L level. Consequently, as shown in state Sf, charges are accumulated in the charge-voltage conversion unit 130 in which the saturation charge of the photoelectric conversion unit 110 is added to the charge accumulated in the charge reset unit 140 via the intermediate potential. In other words, charges corresponding to the saturation charge amount of the photoelectric conversion unit 110 are accumulated in the charge-voltage conversion unit 130.

[0066] Then, from time tf to time tg, the pixel is in an exposure state, and charges according to the exposure time are accumulated in the photoelectric conversion unit 110. Note that as the exposure time, the length between time tf and time tg can be flexibly set.

[0067] When the exposure time has elapsed, as Figure 5 As shown in state Sg, the photoelectric conversion unit 110 and the charge-voltage conversion unit 130 reach their respective saturation levels under high illumination. The charge transfer unit 120 and the charge reset unit 140 have an overflow path through which charge is transferred even in the non-conducting state, so that a current proportional to the amount of incident light flows to the charge-voltage conversion unit 130. It is known that the voltage of such a charge-voltage conversion unit 130 has a value according to the logarithm of the amount of incident light. At time tg, the selection control unit 221 sets the selection signal SEL to the H level. Therefore, the pixel selection unit 160 enters the conductive state, that is, the pixel becomes the selected state. At time t(S2), the column processing unit 230 reads the potential of the charge-voltage conversion unit 130 at this time as the signal S2 under high illumination.

[0068] On the other hand, Figure 6 As shown in the state Sg of FIG, although the charge according to the exposure time is accumulated in the photoelectric conversion unit 110 at time tg under low illuminance, the charge accumulated in the photoelectric conversion unit 110 under low illuminance is not saturated. Therefore, at time t(S2), the column processing unit 230 reads the potential of the charge-voltage conversion unit 130 at this time as the signal S2 under high illuminance. In other words, when the illuminance is high, the charge accumulated in the charge-voltage conversion unit 130 is read as the signal S2, and the state Sf does not change.

[0069] At time th, when the reset control unit 222 sets the reset signal RST to H level, the charge reset unit 140 enters the on state. Therefore, as shown in state Sh, the charge accumulated in the charge-voltage conversion unit 130 is discharged to the reset drain through the charge reset unit 140.

[0070] At time ti, when the reset control unit 222 puts the reset signal RST at the L level, the charge reset unit 140 enters a non-conductive state.

[0071] At time t( N1 ), the column processing unit 230 reads the potential of the charge-voltage conversion unit 130 as a noise signal N1 under low illumination.

[0072] At time tj, when the transfer control unit 223 sets the transfer signal TRG to H level, the charge transfer unit 120 enters the on state. Therefore, as shown in state Sj, the charge accumulated in the photoelectric conversion unit 110 is transferred to the charge-voltage conversion unit 130.

[0073] At time tk, the transfer control unit 223 stops generating the transfer signal TRG. Consequently, the charge transfer unit 120 enters an off state, and therefore does not transfer the charge accumulated in the photoelectric conversion unit 110. Therefore, as shown in state Sk, the charge read from the photoelectric conversion unit 110 is accumulated in the charge-voltage conversion unit 130.

[0074] Therefore, at time t( S1 ), the column processing unit 230 reads the potential of the charge-voltage conversion unit 130 at that time as the signal S1 under low illumination.

[0075] At time t1, the reset drain control unit 224 changes the reset drain voltage VRD from the reset potential Vrst to the voltage Vmid, and the charge in the photoelectric conversion unit 110 is saturated again at the voltage Vmid. Therefore, as shown in state S1, the photoelectric conversion unit 110, the charge-voltage conversion unit 130, and the reset drain all have the voltage Vmid and enter a state full of charge in a manner similar to state Sa.

[0076] Furthermore, at time tm, the reset drain control unit 224 returns the reset drain voltage VRD to the reset voltage Vrst. At this time, the charge transfer unit 120 and the charge reset unit 140 remain in a non-conductive state. Therefore, as shown in state Sm, the photoelectric conversion unit 110 and the charge-voltage conversion unit 130 reach their respective saturation levels.

[0077] At time tn, the reset control unit 222 applies the intermediate potential to the reset signal RST. In addition, the transfer control unit 223 sets the transfer signal TRG to the H level. Therefore, as shown in state Sn, the charge accumulated in the charge reset unit 140 by the intermediate potential remains in the charge-voltage conversion unit 130.

[0078] At time to, the transfer control unit 223 sets the transfer signal TRG to an L level. In response to this, the charge transfer unit 120 enters a non-conductive state.

[0079] At time tp, the reset control unit 222 sets the reset signal RST to an L level. In response to this, the charge reset unit 140 enters a non-conductive state.

[0080] At time t(N2), the column processing unit 230 reads the potential of the charge-voltage conversion unit 130 as the noise signal N2 under high illumination. Therefore, by subtracting the noise signal N2 from the pixel signal S2, the influence of the change in the threshold Vth of the charge reset unit 140 on each pixel can be reduced.

[0081] In other words, the column processing unit 230 outputs ( S1 - N1 ) as an image signal under low illuminance, and outputs ( S2 - N2 ) as an image signal under high illuminance.

[0082] Figure 7 1 is a diagram illustrating an exemplary operation of the discharge unit 180 in each pixel of the pixel array unit 100 according to an embodiment of the present technology. While the exemplary operation without the discharge unit 180 has been described above, the exemplary operation with the discharge unit 180 will be described below. In this example, the discharge unit 180 remains on during the reset operation of logarithmic reading to selectively discharge the charge accumulated by light reception in the photoelectric conversion unit 110.

[0083] The state Sq is a state corresponding to the above-described state S1, in which the photoelectric conversion unit 110, the charge-voltage conversion unit 130, and the reset drain all have Vmid and are fully charged.

[0084] The reset drain control unit 224 then returns the reset drain voltage VRD to the reset voltage Vrst. At this point, the charge transfer unit 120 and the charge reset unit 140 remain in a non-conductive state. Consequently, the photoelectric conversion unit 110 and the charge-voltage conversion unit 130 reach their respective saturation levels. The discharge control unit 225 then sets the overflow gate signal OFG to an H level. In response, the discharge unit 180 enters a conductive state. Consequently, as shown in state Sr, the charge accumulated in the photoelectric conversion unit 110 is discharged through the discharge unit 180.

[0085] Then, the reset control unit 222 applies the intermediate potential to the reset signal RST. In addition, the transfer control unit 223 temporarily sets the transfer signal TRG to the H level and then sets the transfer signal TRG to the L level. Therefore, as shown in the state Ss, the charge accumulated in the charge reset unit 140 by the intermediate potential remains in the charge-voltage conversion unit 130.

[0086] Then, the reset control unit 222 sets the reset signal RST to L level. In response to this, the charge reset unit 140 enters a non-conductive state. In this case, the column processing unit 230 reads the noise signal N2 under high illuminance by logarithmic reading.

[0087] In this manner, by keeping the discharge unit 180 turned on during the reset operation of logarithmic reading to discharge charges accumulated by light reception in the photoelectric conversion unit 110 , charges can be prevented from overflowing from the charge transfer unit 120 and mixing into the charge-voltage conversion unit 130 .

[0088] [Pixel structure]

[0089] Figure 8 This is a diagram showing an exemplary configuration of each pixel of the pixel array unit 100 in the first embodiment of the present technology. As described above, when reading light with high illumination levels through logarithmic reading, it is necessary to allow charge to overflow from the photoelectric conversion unit to the drain power supply. Therefore, a small photoelectric conversion unit is advantageous. On the other hand, when the size of the photoelectric conversion unit is reduced, sensitivity is sufficient for reading light with low illumination levels through linear reading. Therefore, in this embodiment, each pixel includes within it: a first photoelectric conversion unit 111 that photoelectrically converts incident light into charge and accumulates the charge in a first region; and a second photoelectric conversion unit 112 that photoelectrically converts incident light into charge and accumulates the charge in a second region, the area of the second region being smaller than that of the first region. In other words, within one pixel region, a large photoelectric conversion unit 111 and a small photoelectric conversion unit 112 of different sizes are provided. Note that the photoelectric conversion unit 111 and the photoelectric conversion unit 112 are examples of the first photoelectric conversion unit and the second photoelectric conversion unit described in the claims.

[0090] Charge transfer units 121 and 122 are provided corresponding to photoelectric conversion units 111 and 112, respectively. Transfer signals TGL and TGS are supplied to charge transfer units 121 and 122, respectively, via transfer control unit 223. Meanwhile, charge-voltage conversion unit 130, charge reset unit 140, signal amplification unit 150, and pixel selection unit 160 are similar to those in the aforementioned circuit configuration and are shared within a single pixel. Note that charge transfer units 121 and 122 are examples of the first and second charge transfer units described in the claims.

[0091] In addition, in this example, the discharge unit 181 is connected only to the photoelectric conversion unit 111, and is not connected to the photoelectric conversion unit 112. The discharge unit 181 discharges the charge accumulated in the photoelectric conversion unit 111 according to the overflow gate signal OFGL supplied from the discharge control unit 225. Note that the discharge unit 181 is an example of the first discharge unit described in the claims.

[0092] In the exemplary configuration of the first embodiment, the photoelectric conversion unit 111, which has a large area, acquires signals at relatively low illumination levels by performing conventional linear reading. On the other hand, the photoelectric conversion unit 112, which has a small area, acquires signals at relatively high illumination levels by using logarithmic reading. The signal processing unit 280 then combines the signals obtained through readings appropriate for the respective illumination levels in each pixel region, enabling the acquisition of an image with a high dynamic range.

[0093] When the large photoelectric conversion unit 111 and the small photoelectric conversion unit 112 are arranged in this manner, if a signal from the photoelectric conversion unit 112 (which has a small area and performs logarithmic reading) is mixed into the photoelectric conversion unit 111 having a large area, charge may overflow from the photoelectric conversion unit 111 to an unintended location. In this regard, in this embodiment, since the discharge unit 181 is connected to the photoelectric conversion unit 111 having a large area, when logarithmic reading is performed in the photoelectric conversion unit 112, the discharge unit 181 remains on to discharge charge from the photoelectric conversion unit 111. Therefore, charge can be prevented from mixing into the photoelectric conversion unit 111 during logarithmic reading.

[0094] In this manner, in the first embodiment of the present technology, photoelectric conversion units 111 and 112 of different sizes are provided within each pixel, and the discharge unit 181 is connected only to the photoelectric conversion unit 111 having a larger area. Furthermore, when logarithmic reading is performed in the photoelectric conversion unit 112, the discharge unit 181 remains on to discharge charge from the photoelectric conversion unit 111. Therefore, charge can be prevented from being mixed into the photoelectric conversion unit 111 during logarithmic reading, thereby preventing malfunctions.

[0095] [Modification]

[0096] Figure 9 This diagram illustrates an exemplary configuration of each pixel in a pixel array unit 100 in a modification of the first embodiment of the present technology. In this modification, a discharge cell 181 is connected to a large-area photoelectric conversion cell 111, and a discharge cell 182 is connected to a small-area photoelectric conversion cell 112, which is provided within the pixel. Note that discharge cell 182 is an example of the second discharge cell described in the claims.

[0097] As described above, since light is received even when reading noise in an operation for reducing variation, and since the illuminance is high when the photoelectric conversion unit 112 having a small area performs logarithmic reading, overflowing charge may be mixed into the charge-voltage conversion unit 130 after an intermediate reset. Therefore, the discharge unit 182 connected to the photoelectric conversion unit 112 having a small area remains on during the reset operation of the logarithmic reading to selectively discharge the charge accumulated by light reception in the photoelectric conversion unit 112. This configuration prevents the mixing of signals during the reset operation using the intermediate potential of the charge reset unit 140.

[0098] In this manner, in the modified example of the first embodiment of the present technology, the discharge unit 182 is connected to the photoelectric conversion unit 112 having a small area, and is kept on during the reset operation of the logarithmic reading to selectively discharge the charge accumulated by light reception in the photoelectric conversion unit 112. With this configuration, it is possible to prevent the mixing of signals during the reset operation using the intermediate potential of the charge reset unit 140.

[0099] <2. Second embodiment>

[0100] In the first embodiment described above, normal reading is performed by the large-area photoelectric conversion unit 111 under low illuminance, and logarithmic reading is performed by the small-area photoelectric conversion unit 112 under high illuminance. However, if the illuminance is too low, sufficient resolution cannot be achieved even with the large-area photoelectric conversion unit 111, and accurate reading may become difficult. Therefore, in the second embodiment, a conversion efficiency switching unit is provided between the photoelectric conversion unit 111 and the photoelectric conversion unit 112 to improve conversion efficiency when the illuminance is too low to allow high-precision reading.

[0101] [Pixel structure]

[0102] Figure 10 1 is a diagram showing an exemplary configuration of each pixel of the pixel array unit 100 in the second embodiment of the present technology. Note that since the entire configuration of the solid-state imaging device 10 is similar to that in the above-described first embodiment, detailed description thereof will be omitted.

[0103] In the second embodiment, discharge units 181 and 182 are connected to the large photoelectric conversion unit 111 and the small photoelectric conversion unit 112, respectively, in a manner similar to the modified example of the first embodiment described above. Furthermore, a conversion efficiency switching unit 190 is provided between the charge transfer unit 121 and the charge transfer unit 122, which are connected to the photoelectric conversion unit 111 and the photoelectric conversion unit 112, respectively. Conversion efficiency switching unit 190 switches the conversion efficiency from the charge accumulated in the charge-voltage conversion unit 130 to the voltage. Conversion efficiency switching unit 190 is controlled by a conversion efficiency switching signal FDG supplied from the vertical drive unit 220 and performs an on-off operation like a transistor. This configuration allows the capacitance of the charge-voltage conversion unit 130 to be switched, thereby switching the gain (amplification level) of the signal amplification unit 150.

[0104] Figure 11 is a diagram illustrating exemplary potentials in an operating state of the second embodiment of the present technology.

[0105] exist Figure 11 In FIG. 1 , a shows the state when the photoelectric conversion unit 112 with a small area performs logarithmic reading. As described above, the photoelectric conversion unit 112 with a small area performs logarithmic reading for a high-illuminance signal. At this time, it is necessary to keep the conversion efficiency switching unit 190 turned on. In other words, the conversion efficiency switching signal FDG becomes H level, and the capacitance of the charge-voltage conversion unit 130 becomes similar to that of the first embodiment described above.

[0106] exist Figure 11 In FIG. 1 , portion b shows a state where the photoelectric conversion unit 111, which has a large area, performs high-sensitivity reading. To obtain a low-light signal with higher sensitivity, the conversion efficiency switching unit 190 remains off to reduce the capacitance of the charge-voltage conversion unit 130. In other words, the conversion efficiency switching signal FDG is turned to an L level to keep the conversion efficiency switching unit 190 off. This configuration allows for sufficient resolution for low-light signals.

[0107] exist Figure 11 In FIG. 1 , c shows the state when the photoelectric conversion unit 111 with a large area performs normal sensitivity reading. Normal sensitivity reading by the photoelectric conversion unit 111 with a large area is performed for a signal with a certain illuminance, for which high resolution is not required by keeping the conversion efficiency switching unit 190 turned on. In other words, the conversion efficiency switching signal FDG becomes H level, thereby changing the capacitance of the charge-voltage conversion unit 130 to a state similar to that of the first embodiment described above.

[0108] Figure 12 This figure shows an example of the light response characteristics of each pixel of the pixel array unit 100 in the second embodiment of the present technology. Here, the amount of light targeted for high-sensitivity reading is defined as low illuminance, the amount of light targeted for logarithmic reading is defined as high illuminance, and the connecting range between low illuminance and high illuminance is defined as medium illuminance.

[0109] exist Figure 12 In Figure 1, a shows the light response characteristics when logarithmic reading is performed using the small-area photoelectric conversion unit 112. At this time, the conversion efficiency switching unit 190 is in the on state, and a high-illuminance signal is acquired logarithmically. Although the high-illuminance signal is saturated when reading using the large-area photoelectric conversion unit 111, and the value remains constant regardless of the light intensity, logarithmic reading enables acquisition of the signal intensity that varies with the light intensity.

[0110] exist Figure 12 In FIG, b shows the light response characteristics of the photoelectric conversion unit 111 having a large area performing high-sensitivity reading. At this time, the conversion efficiency switching unit 190 is in the off state, and sufficient resolution can be obtained for a low-illuminance signal.

[0111] exist Figure 12 In Figure 3, c shows the light response characteristics of a photoelectric conversion unit 111 having a large area performing normal sensitivity reading. At this time, the conversion efficiency switching unit 190 is in the on state, and compared to the low-illuminance case, the resolution is reduced while the receivable light amount range is expanded to obtain a medium-illuminance signal within the connecting range between high and low illuminance. The response in the medium-illuminance area varies depending on the driving.

[0112] The signal processing unit 280 multiplies the signal obtained by the photoelectric conversion unit 112 performing logarithmic reading and the signal obtained by the photoelectric conversion unit 111 performing normal sensitivity reading by the conversion efficiency ratio to generate an image conforming to the signal level in high sensitivity reading.

[0113] [Read Timing]

[0114] Figure 13 is a diagram showing an example of the read timing of each pixel of the pixel array unit 100 in the second embodiment of the present technology.

[0115] First, after resetting the large-area photoelectric conversion unit 111, exposure is performed (801). Signal reading and noise reading at low and medium illumination levels are performed through exposure (802-805). More specifically, with the conversion efficiency switching unit 190 turned on, medium illumination noise is read at normal sensitivity (802). Then, with the conversion efficiency switching unit 190 turned off, low illumination noise and signal are read at high sensitivity (803, 804). Then, with the conversion efficiency switching unit 190 turned on again, medium illumination signal reading is performed at normal sensitivity (805).

[0116] During this period, the discharge unit 181 connected to the photoelectric conversion unit 111 is in the off state, and the discharge unit 182 connected to the photoelectric conversion unit 112 is in the on state. In other words, although exposure and reading are performed in the photoelectric conversion unit 111 having a large area, on the other hand, since the charge is released, reading is not performed in the photoelectric conversion unit 112 having a small area.

[0117] Then, the discharge unit 181 connected to the photoelectric conversion unit 111 enters the on state, and the discharge unit 182 connected to the photoelectric conversion unit 112 enters the off state. Therefore, since the charge is released, reading is not performed in the photoelectric conversion unit 111 having a large area. Then, after resetting by the intermediate potential of the charge reset unit 140, exposure (806) is performed in the photoelectric conversion unit 112 having a small area. Logarithmic reading of the signal and noise under high illumination is performed by exposure (807, 808). Note that in order to reduce the mixing of signals during the resetting by the intermediate potential of the charge reset unit 140, the discharge unit 182 connected to the photoelectric conversion unit 112 is in the on state (808) during the logarithmic reading of the noise, and further, during the logarithmic reading, the conversion efficiency switching unit 190 is in the open state (conductive state).

[0118] In this manner, according to the second embodiment of the present technology, by providing the conversion efficiency switching unit 190 between the photoelectric conversion unit 111 and the photoelectric conversion unit 112 , the conversion efficiency for low illuminance signals can be improved, thereby performing reading with high accuracy.

[0119] Note that the above embodiments are described as examples for implementing the present technology, and there is a correspondence between the contents of the embodiments and the contents of the claims that specify the present invention. Similarly, there is a correspondence between the contents of the claims that specify the present invention and the contents identified with the same names as those that specify the contents of the present technology in the embodiments. However, the present technology is not limited to these embodiments, and it is possible to implement the present technology by making various modifications to these embodiments within the scope of the present technology.

[0120] In addition, the series of program steps described in the above embodiments may be regarded as a method including a series of program steps, or may be regarded as a program for causing a computer to execute the series of program steps or a recording medium in which the program is stored. For example, a compact disc (CD), a mini disc (MD), a digital versatile disc (DVD), a memory card, a Blu-ray (registered trademark) disc, etc. can be used as the recording medium.

[0121] Note that the effects described in this specification are merely examples. The effects of this technology are not limited to the described effects, and this technology may have other effects.

[0122] Furthermore, the present technology can also be configured as follows.

[0123] (1) A solid-state imaging device comprising:

[0124] a first photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in the first region;

[0125] a second photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in a second region whose area is smaller than that of the first region;

[0126] a charge-voltage conversion unit configured to accumulate charges photoelectrically converted by the first photoelectric conversion unit and the second photoelectric conversion unit to convert the charges into a voltage;

[0127] a first charge transfer unit configured to transfer the charge accumulated in the first photoelectric conversion unit to the charge-voltage conversion unit;

[0128] a second charge transfer unit configured to transfer the charge accumulated in the second photoelectric conversion unit to the charge-voltage conversion unit;

[0129] a charge resetting unit configured to reset the charge accumulated in the charge-voltage conversion unit; and

[0130] a first discharge unit configured to discharge the charge accumulated in the first photoelectric conversion unit.

[0131] (2) The solid-state imaging device according to (1) further includes a driving unit configured to perform driving in such a manner that the driving unit causes the first discharge unit to release the charge accumulated in the first photoelectric conversion unit, while controlling the potential of the drain of the charge reset unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, and then exposes the second photoelectric conversion unit.

[0132] (3) The solid-state image pickup device according to (2), further including a second discharge unit configured to discharge the charge accumulated in the second photoelectric conversion unit, wherein

[0133] The driving unit performs driving in such a manner that the driving unit causes the first discharge unit to discharge the charge accumulated in the first photoelectric conversion unit while controlling the potential of the drain of the charge reset unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, then causes the second discharge unit to discharge the charge accumulated in the second photoelectric conversion unit while applying an intermediate potential to the charge reset unit to accumulate the charge in the charge-voltage conversion unit, the driving unit also causes the charge reset unit to become a non-conductive state, then causes the charge accumulated in the charge-voltage conversion unit to be transferred to the charge-voltage conversion unit, and then exposes the second photoelectric conversion unit.

[0134] (4) The solid-state imaging device according to (3), further including a signal amplifying unit configured to amplify the charge accumulated in the charge-voltage conversion unit and output a pixel signal of a level corresponding to the charge.

[0135] (5) The solid-state imaging device according to (4), further including a conversion efficiency switching unit configured to switch the capacitance of the charge-voltage conversion unit to thereby switch the degree of amplification in the signal amplification unit.

[0136] (6) A method for driving a solid-state imaging device, the solid-state imaging device comprising:

[0137] a first photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in the first region,

[0138] a second photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in a second region whose area is smaller than that of the first region,

[0139] a charge-voltage conversion unit configured to accumulate the charges photoelectrically converted by the first photoelectric conversion unit and the second photoelectric conversion unit to convert the charges into a voltage,

[0140] a first charge transfer unit configured to transfer the charge accumulated in the first photoelectric conversion unit to the charge-voltage conversion unit,

[0141] a second charge transfer unit configured to transfer the charge accumulated in the second photoelectric conversion unit to the charge-voltage conversion unit,

[0142] a charge resetting unit configured to reset the charge accumulated in the charge-voltage conversion unit, and

[0143] a first discharging unit configured to discharge the charge accumulated in the first photoelectric conversion unit, the driving method comprising:

[0144] Driving is performed in such a manner that the first discharge unit is caused to discharge the charge accumulated in the first photoelectric conversion unit while controlling the potential of the drain of the charge resetting unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, and then the second photoelectric conversion unit is exposed.

[0145] (7) An electronic device comprising:

[0146] a first photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in the first region;

[0147] a second photoelectric conversion unit configured to photoelectrically convert incident light into electric charges and accumulate the electric charges in a second region whose area is smaller than that of the first region;

[0148] a charge-voltage conversion unit configured to accumulate charges photoelectrically converted by the first photoelectric conversion unit and the second photoelectric conversion unit to convert the charges into a voltage;

[0149] a first charge transfer unit configured to transfer the charge accumulated in the first photoelectric conversion unit to the charge-voltage conversion unit;

[0150] a second charge transfer unit configured to transfer the charge accumulated in the second photoelectric conversion unit to the charge-voltage conversion unit;

[0151] a charge resetting unit configured to reset the charge accumulated in the charge-voltage conversion unit;

[0152] a first discharge unit configured to discharge charges accumulated in the first photoelectric conversion unit; and

[0153] a driving unit configured to perform driving in such a manner that the driving unit causes the first discharging unit to discharge the charge accumulated in the first photoelectric conversion unit, while controlling the potential of the drain of the charge resetting unit to accumulate the charge in the second photoelectric conversion unit and the charge-voltage conversion unit to a saturation level, and then exposing the second photoelectric conversion unit.

[0154] Reference Signs List

[0155] 10 Solid-state imaging device

[0156] 100 pixel array unit

[0157] 110 to 112 Photoelectric conversion unit

[0158] 120 to 122 Charge Transfer Units

[0159] 130 charge-voltage conversion unit

[0160] 140 Charge reset unit

[0161] 150 signal amplification unit

[0162] 160 pixel selection unit

[0163] 170 Constant Current Source

[0164] 180 to 182 discharge units

[0165] 190 conversion efficiency switching unit

[0166] 220 vertical drive unit

[0167] 221 Select control unit

[0168] 222 Reset control unit

[0169] 223 Transmission Control Unit

[0170] 224 Reset drain control unit

[0171] 225 Discharge Control Unit

[0172] 229 pixel drive lines

[0173] 230 columns of processing units

[0174] 239 vertical signal line

[0175] 240 horizontal drive unit

[0176] 250 System Control Unit

[0177] 280 signal processing unit

[0178] 290 data storage unit.

Claims

1. A camera device comprising: a first photoelectric conversion region configured to photoelectrically convert incident light into electric charges and accumulate the electric charges; a second photoelectric conversion region configured to photoelectrically convert incident light into electric charges, wherein an area of the first photoelectric conversion region is larger than an area of the second photoelectric conversion region; a floating diffusion region configured to accumulate charges photoelectrically converted by the first photoelectric conversion region and the second photoelectric conversion region to convert the charges into a voltage; a first charge transfer transistor configured to transfer charges accumulated in the first photoelectric conversion region to the floating diffusion region; a second charge transfer transistor configured to transfer charges accumulated in the second photoelectric conversion region to the floating diffusion region; a charge reset transistor configured to reset charges accumulated in the floating diffusion region; a first discharge transistor configured to discharge charge accumulated in the first photoelectric conversion region when logarithmic reading is performed in the second photoelectric conversion region; a second discharge transistor configured to discharge the charge accumulated in the second photoelectric conversion region.

2. The imaging device according to claim 1, wherein The image pickup device further includes a signal amplifying unit configured to amplify the charges accumulated in the floating diffusion region and output a pixel signal of a level corresponding to the charges.

3. The imaging device according to claim 2, wherein: The image pickup device further includes a conversion efficiency switching unit configured to switch the capacitance of the floating diffusion region, thereby switching the degree of amplification in the signal amplification unit.

4. The imaging device according to claim 2, wherein: The image pickup device further includes a pixel selection unit configured to select any pixel in a pixel array unit included in the image pickup device.

5. The imaging device according to claim 3, wherein: The conversion efficiency switching unit is provided between the first charge transfer transistor and the second charge transfer transistor. The imaging device according to claim 3 , wherein: The camera device further includes a pixel array unit provided with pixels and a driving unit, wherein the driving unit is used to drive the pixels of the pixel array unit, and the driving unit is used to control the conversion efficiency switching unit.

7. The imaging device according to claim 1, wherein: The floating diffusion region is disposed between the first charge transfer transistor and the second charge transfer transistor.

8. The imaging device according to claim 5, wherein: The floating diffusion region is disposed between the first charge transfer transistor and the conversion efficiency switching unit.

9. The imaging device according to claim 4, wherein: The signal amplifying unit is disposed between the floating diffusion region and the pixel selecting unit.

10. An electronic device, wherein: The electronic device includes the imaging device according to any one of claims 1 to 9.

Images