Patent Description:
There has been proposed a solid-state imaging device in which signal charges to be generated in a photoelectric converter provided in a semiconductor layer are transferred to a floating diffusion by a gate electrode embedded in the semiconductor layer (e.g., see PTL <NUM>). Document <CIT> also discloses an imaging device according to the prior-art.

Incidentally, in such a solid-state imaging device, it is desirable that electric charges be smoothly transferred from the photoelectric converter to a transfer destination.

Accordingly, it is desirable to provide an imaging device having excellent operation reliability and an electronic apparatus including such an imaging device.

An imaging device according to an embodiment of the present disclosure includes: a semiconductor layer having a front surface and a back surface, the back surface being on an opposite side of the front surface; a photoelectric converter that is embedded in the semiconductor layer and generates electric charges corresponding to a received light amount; and a transfer section that includes a first trench gate and a second trench gate and transfers the electric charges from the photoelectric converter to a single transfer destination via the first trench gate and the second trench gate, the first trench gate and the second trench gate each extending from the front surface to the back surface of the semiconductor layer into the photoelectric converter. The first trench gate has a first length from the front surface to the photoelectric converter, and the second trench gate has a second length from the front surface to the photoelectric converter, the second length being shorter than the first length.

Further, an electronic apparatus according to an embodiment of the present disclosure includes the above-described imaging device.

In the imaging device and the electronic apparatus according to the embodiments of the present disclosure each having such a configuration as described above, even if there is a potential dip in the photoelectric converter when the transfer section is in an off state, the potential dip is eliminated when the transfer section is in an on state.

According to the imaging device and the electronic apparatus of the embodiments of the present disclosure, electric charges are smoothly transferred from the photoelectric converter to the transfer destination, and it is possible to achieve excellent imaging performance.

It is to be noted that effects of the present disclosure are not limited to the above and may include any of effects described below.

The following describes embodiments of the present disclosure in detail with reference to the drawings. It is to be noted that description is given in the following order.

<FIG> is a block diagram illustrating a configuration example of a function of a solid-state imaging device 101A according to a first embodiment of the present technology.

The solid-state imaging device 101A is a so-called global shutter mode backside illumination image sensor such as, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The solid-state imaging device 101A receives light from a subject, photoelectrically converts the light, and generates image signals to capture an image.

The global shutter mode is basically a mode in which global exposure is performed in which exposure is started at the same time for all pixels and exposure is terminated at the same time for all pixels. Here, the all pixels mean all of the pixels of a portion appearing in the image, and dummy pixels and the like are excluded. Further, if time difference or image distortion is sufficiently small to the extent that it does not pose an issue, a mode of moving an area for performing the global exposure while performing the global exposure in units of multiple rows (e.g., several tens of rows) rather than all pixels simultaneously is also included in the global shutter mode. In addition, a mode of performing the global exposure for pixels in a predetermined area, rather than all of the pixels of the portion appearing in the image, is also included in the global shutter mode.

The backside illumination image sensor refers to an image sensor having a configuration in which a photoelectric converter such as a photodiode that receives light from the subject and converts the light into an electric signal is provided between: a light receiving surface into which the light from the subject enters; and a wiring layer provided with a wiring line such as a transistor that drives each pixel or the like.

The solid-state imaging device 101A includes, for example, a pixel array <NUM>, a vertical driver <NUM>, a column signal processor <NUM>, a data storage <NUM>, a horizontal driver <NUM>, a system controller <NUM>, and a signal processor <NUM>.

The solid-state imaging device 101A has the pixel array <NUM> formed on a semiconductor layer <NUM> (to be described later). Peripheral circuits such as the vertical driver <NUM>, the column signal processor <NUM>, the data storage <NUM>, the horizontal driver <NUM>, the system controller <NUM>, and the signal processor <NUM> are formed on the semiconductor layer <NUM> on which the pixel array <NUM> is formed, for example.

The pixel array <NUM> has a plurality of sensor pixels <NUM> each including a photoelectric converter <NUM> (to be described later) that generates electric charges corresponding to an amount of light entered from a subject and accumulates the electric charges. As illustrated in <FIG>, the sensor pixels <NUM> are arranged in a horizontal direction (row direction) and in a vertical direction (column direction). In the pixel array <NUM>, a pixel drive line <NUM> is wired along the row direction for each pixel row including sensor pixels <NUM> arranged in line in the row direction, and a vertical signal line (VSL) <NUM> is wired along the column direction for each pixel column including sensor pixels <NUM> arranged in line in the column direction.

The vertical driver <NUM> includes a shift register, an address decoder, and the like. The vertical driver <NUM> simultaneously drives all of the plurality of sensor pixels <NUM> in the pixel array <NUM> or drives them in pixel row units by supplying signals or the like to the plurality of sensor pixels <NUM> via the respective plurality of pixel drive lines <NUM>.

The vertical driver <NUM> includes two scanning systems, e.g., a readout scanning system and a sweep scanning system. The readout scanning system selects and scans the unit pixels of the pixel array <NUM> in rows in order to read out signals from the unit pixels. The sweep scanning system performs, on a readout row on which readout scanning is to be performed by the readout scanning system, sweep scanning in advance of the readout scanning by time of a shutter speed.

Owing to the sweep scanning performed by the sweep scanning system, unnecessary electric charges are swept out from the photoelectric converter <NUM> of the unit pixels of the readout row. This is called reset. Then, owing to the sweeping out of the unnecessary electric charges by the sweeping scanning system, that is, resetting, a so-called electronic shutter operation is performed. Here, the electronic shutter operation refers to an operation in which optical charges of the photoelectric converter <NUM> are discharged and the exposure is newly started, that is, accumulation of the optical charges is newly started.

Signals to be read out by a readout operation by the readout scanning system corresponds to an amount of light that has entered after the immediately previous readout operation or electronic shutter operation. An accumulation time of the optical charges in the unit pixels, i.e., an exposure time, is a period from a timing of the reading out of the immediately previous readout operation or a timing of the sweeping out of the immediately previous electronic shutter operation to a timing of the reading out of the current readout operation.

The signal to be outputted from each unit pixel of the pixel row selected and scanned by the vertical driver <NUM> is supplied to the column signal processor <NUM> through one of the vertical signal lines <NUM>. The column signal processor <NUM> performs a predetermined signal process on the signal outputted from each unit pixel of the selected row through the vertical signal line <NUM> for each pixel column of the pixel array <NUM>, and temporarily holds the pixel signal that has been subjected to the signal process.

Specifically, the column signal processor <NUM> includes, for example, a shift register or an address decoder, and performs a noise elimination process, a correlation double sampling process, an A/D (Analog/Digital) conversion A/D conversion process on analog pixel signals, etc., to generate digital pixel signals. The column signal processor <NUM> supplies the generated pixel signals to the signal processor <NUM>.

The horizontal driver <NUM> includes a shift register, an address decoder, and the like, and sequentially selects unit circuits corresponding to the pixel columns of the column signal processor <NUM>. Owing to the selection scanning by the horizontal driver <NUM>, the pixel signals processed for each unit circuit in the column signal processor <NUM> are sequentially outputted to the signal processor <NUM>.

The system controller <NUM> includes a timing generator or the like which generates various timing signals. The system controller <NUM> controls driving of the vertical driver <NUM>, the column signal processor <NUM>, and the horizontal driver <NUM> on the basis of the timing signals generated by the timing generator.

The signal processor <NUM> performs, while temporarily storing data in the data storage <NUM> as necessary, a signal process such as an arithmetic process on the pixel signals supplied from the column signal processor <NUM>, and outputs image signals including the respective pixel signals.

The data storage <NUM> temporarily stores data necessary for the signal process for when the signal process is to be performed in the signal processor <NUM>.

It is to be noted that the solid-state imaging device according to the present technology is not limited to the solid-state imaging device 101A illustrated in <FIG>, and may have a configuration such as a solid-state imaging device 101B illustrated in <FIG> or a solid-state imaging device 101C illustrated in <FIG>, for example. <FIG> is a block diagram illustrating a configuration example of a function of the solid-state imaging device 101B according to a first modification example of the first embodiment of the present technology. <FIG> is a block diagram illustrating a configuration example of a function of the solid-state imaging device 101C according to a second modification example of the first embodiment of the present technology.

The solid-state imaging device 101B illustrated in <FIG> has the data storage <NUM> disposed between the column signal processor <NUM> and the horizontal driver <NUM>, and the pixel signals outputted from the column signal processor <NUM> are supplied to the signal processor <NUM> via the data storage <NUM>.

Further, the solid-state imaging device 101C illustrated in <FIG> has the data storage <NUM> and the signal processor <NUM> disposed in parallel between the column signal processor <NUM> and the horizontal driver <NUM>. In the solid-state imaging device 101C, the column signal processor <NUM> performs the A/D conversion for converting analog pixel signals into digital pixel signals for each column of the pixel array <NUM> or for every multiple columns of the pixel array <NUM>.

Next, referring to <FIG>, a circuit configuration example of the sensor pixel <NUM> provided in the pixel array <NUM> of <FIG> will be described. <FIG> is a circuit configuration example of one sensor pixel <NUM> out of the plurality of sensor pixels <NUM> included in the pixel array <NUM>.

In the example illustrated in <FIG>, the sensor pixel <NUM> in the pixel array <NUM> includes a photoelectric converter (PD) <NUM>, a transfer transistor (TG) <NUM>, an electric charge-voltage converter (FD) <NUM>, a reset transistor (RST) <NUM>, an amplifier transistor (AMP) <NUM>, and a select transistor (SEL) <NUM>.

In this example, the TG <NUM>, the RST <NUM>, the AMP <NUM>, and the SEL <NUM> are each an N-type MOS transistor. A gate electrode of the TG <NUM>, a gate electrode of the RST <NUM>, a gate electrode of the AMP <NUM>, and a gate electrode of the SEL <NUM> are supplied with drive signals S52, S54, and S56, respectively, by the vertical driver <NUM> and the horizontal driver <NUM> on the basis of the drive control of the system controller <NUM>. The drive signals S52, S54, and S56 are each a pulse signal in which a high level state is an active state (on state) and a low level state is an inactive state (off state). It is to be noted that, in the following, turning the drive signal into the active state is also referred to turning on the drive signal, and turning the drive signal into the inactive state is also referred to as turning off the drive signal.

The PD <NUM> is, for example, a photoelectric conversion element including a photodiode of a PN-junction, and is configured to receive light from a subject, generate electric charges corresponding to the received light amount by the photoelectric conversion, and accumulate the electric charges.

The TG <NUM> is coupled between the PD <NUM> and the FD <NUM>, and is configured to transfer the electric charges accumulated in the PD <NUM> to the FD <NUM> in response to the drive signal S52 applied to the gate electrode of the TG <NUM>. The TG <NUM> is a specific example corresponding to "transfer section" of the present disclosure.

The RST <NUM> has a drain coupled to a power source VDD and a source coupled to the FD <NUM>. The RST <NUM> initializes or resets the FD <NUM> in response to the drive signal S54 applied to the gate electrode of the RST <NUM>. For example, when the drive signal S58 is turned on and the RST <NUM> is turned on, a potential of the FD <NUM> is reset to a voltage level of the power source VDD. That is, the FD <NUM> is initialized.

The FD <NUM> is a floating diffusion region which converts the electric charges transferred from the PD <NUM> via the TG <NUM> into electric signals (e.g., voltage signals) and outputs the electric signals. The RST <NUM> is coupled to the FD <NUM>, and the vertical signal line VSL is also coupled to the FD <NUM> via the AMP <NUM> and the SEL <NUM>.

Next, with reference to <FIG> and <FIG>, a plane configuration example and a cross-sectional configuration example of the sensor pixel <NUM> provided in the pixel array <NUM> of <FIG> will be described. <FIG> illustrates a plane configuration example of one sensor pixel <NUM> out of the plurality of sensor pixels <NUM> included in the pixel array <NUM>. <FIG> illustrates a cross-sectional configuration example of one sensor pixel <NUM>, which corresponds to a cross-section of an arrow direction taken along a line IV-IV illustrated in <FIG>. However, in <FIG>, a portion between a position P1 and a position P2 indicates an XZ cross-section along an X-axis direction, otherwise indicates a YZ cross-section along a Y-axis direction.

In the examples illustrated in <FIG> and <FIG>, the PD <NUM> occupies a central region of the sensor pixel <NUM>, and the RST <NUM>, the VDD, the AMP <NUM>, the SEL <NUM>, an FD <NUM>, a VSS, and the VSL <NUM> are provided in a peripheral region thereof. The TG <NUM> and the FD <NUM> are each provided at a position overlapping with the PD <NUM> in a Z-axis direction (also referred to as thickness direction or depth direction). The FD <NUM> is coupled to the FD <NUM> through a metal layer. The VSS is a ground terminal, and is normally set to <NUM> V.

As illustrated in <FIG> and <FIG>, the sensor pixel <NUM> includes: the semiconductor layer <NUM> including a semiconductor material such as Si (silicon); the PD <NUM>, and the TG <NUM> serving as the transfer section. Further, an insulating layer <NUM> including an oxide or the like is provided between: the TG <NUM>; and the semiconductor layer <NUM> and the PD <NUM>. The semiconductor layer <NUM> includes: a front surface 11S1; and a back surface 11S2 that is on an opposite side of the front surface 11S1. The semiconductor layer <NUM> may be provided with a light-shielding section <NUM> so as to surround the PD <NUM>.

The TG <NUM> includes a trench gate <NUM> and a trench gate <NUM>. The TG <NUM> is adapted to transfer, from the PD <NUM> via the trench gate <NUM> and the trench gate <NUM>, electric charges generated and accumulated in the PD <NUM> to an identical transfer destination, i.e., the FD <NUM>. As illustrated in <FIG>, the trench gate <NUM> and the trench gate <NUM> each extend from the front surface 11S1 to the back surface 11S2 of the semiconductor layer <NUM> into the PD <NUM>.

The trench gate <NUM> has a length L521 from the front surface 11S1 to the PD <NUM>. The trench gate <NUM> has a length L522, which is shorter than the length L521, from the front surface 11S1 to the PD <NUM> (L521>L522).

In addition, a diameter D521 of the trench gate <NUM> and a diameter D522 of the trench gate <NUM> are each narrowed toward the back surface 11S2 from the front surface 11S1. Further, a maximum value of the diameter D521 of the trench gate <NUM> is larger than a maximum value of the diameter D522 of the trench gate <NUM>. It is to be noted that, in the example illustrated in <FIG>, the diameter D521 of the trench gate <NUM> and the diameter D522 of the trench gate <NUM> are both maximized at the uppermost portions.

Next, referring to <FIG> in addition to <FIG> and <FIG>, an operation of the sensor pixel <NUM> will be described. In the sensor pixel <NUM>, the drive signal S52 to the TG <NUM> is turned on on the basis of the drive control of the system controller <NUM> when the electric charges generated and accumulated in the PD <NUM> that has received the light from the subject is read out. This causes the accumulated electric charges to be transferred from the PD <NUM> to the FD <NUM> via the trench gate <NUM> and the trench gate <NUM>. It is to be noted that, a potential in the depth direction (Z-axis direction) in the PD <NUM> has a gradient such as to gradually increase toward a shallower position, i.e., a position close to the front surface 11S1, from a deeper position, i.e., a position close to the back surface 11S2.

In reality, however, a potential dip may occur in a portion of the depth direction of the PD <NUM>. The potential dip is a point that has a low potential compared to potentials immediately above and below itself. In particular, when enlarging a dimension of the PD <NUM> in the depth direction, a potential gradient in the depth direction becomes gradual, and the potential dip tends to occur easily. Here, if the TG <NUM> has only one trench gate <NUM>, a potential state in the thickness direction (Z-axis direction) in the PD <NUM> is as indicated in <FIG>, for example. <FIG> is a schematic view of a potential state in the depth direction (Z-axis direction) in the PD <NUM> in a case where it is assumed that the TG <NUM> has only one trench gate <NUM>, and corresponds to the cross section of <FIG>. If the TG <NUM> has only one trench gate <NUM>, in the PD <NUM>, the potential dip (a portion surrounded by a broken line) may remain as it is in a portion of the depth, as indicated in <FIG>. Alternatively, it is also similar in a case where the TG <NUM> has the trench gate <NUM> and the trench gate <NUM> whose lengths are the same as each other.

In contrast, the sensor pixel <NUM> according to the present embodiment includes the TG <NUM> having a relatively long trench gate <NUM> and a relatively short trench gate <NUM>. Accordingly, a modulation force that a potential of the PD <NUM> receives from the TG <NUM> increases when moving from a region in which only the trench gate <NUM> exists to a region in which both the trench gate <NUM> and the trench gate <NUM> exist. Consequently, the potential state in the thickness direction (Z-axis direction) in the PD <NUM> becomes a state indicated in <FIG>, for example, so that the potential dip present in the portion of the depth direction is eliminated. It is to be noted that <FIG> is a schematic view of a potential state in the depth direction (Z-axis direction) in the PD <NUM>, and corresponds to the cross section of <FIG>.

As described above, in the solid-state imaging device 101A according to the present embodiment, the TG <NUM> that transfers the electric charges from the PD <NUM> has the trench gate <NUM> having the length L521 and the trench gate <NUM> having the length L522 shorter than the length L521. Accordingly, even if an unintended potential dip is present in the PD <NUM> in a state in which the TG <NUM> is off, or even if an unintended potential dip is generated in the PD <NUM> for increasing a saturated charge amount, it is possible to eliminate the potential dip in a state in which the TG <NUM> is on. Thus, even in a case where a thickness of the semiconductor layer <NUM> is increased, that is, even in a case where the gradient of the potential along the Z-axis direction becomes gradual, it is possible to smoothly transfer the electric charges from the PD <NUM> to the FD <NUM>. This leads to an expectation of improvement in the operation reliability of the solid-state imaging device 101A.

Further, in the solid-state imaging device 101A according to the present embodiment, the diameter D521 of the trench gate <NUM> and the diameter D522 of the trench gate <NUM> are narrowed toward the back surface 11S2 from the front surface 11S1. Further, the maximum value of the diameter D521 of the trench gate <NUM> is larger than the maximum value of the diameter D522 of the trench gate <NUM>. This provides an advantageous structure for accurately forming the trench gate <NUM> having the larger length L521 and the trench gate <NUM> having the length L522 shorter than the length L521.

<FIG> is a plan view of a sensor pixel 110A according to a third modification example of the first embodiment. It is to be noted that <FIG> corresponds to <FIG> of the first embodiment.

As illustrated in <FIG>, the sensor pixel 110A according to the present modification example is such that the FD <NUM>, which is the transfer destination of the electric charges, is located between the trench gate <NUM> and the trench gate <NUM>. Except for this point, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above.

As described above, according to the sensor pixel 110A of the present modification example, the FD <NUM> serving as the transfer destination is disposed between the trench gate <NUM> and the trench gate <NUM> as compared with the sensor pixel <NUM> according to the above-described first embodiment. In a portion between the trench gate <NUM> and the trench gate <NUM>, a back-bias effect is eliminated and the modulation force received from the TG <NUM> is the highest. Accordingly, the electric charges to be transferred inevitably pass between the trench gate <NUM> and the trench gate <NUM> to be transferred to the front surface 11S1. The presence of the FD <NUM>, which is the transfer destination of the electric charges, in the vicinity of the front surface <NUM> enhances a transfer efficiency of the electric charges from the PD <NUM> to the FD <NUM>.

<FIG> is a plan view of a sensor pixel 110B according to a fourth modification example of the first embodiment. It is to be noted that <FIG> corresponds to <FIG> of the first embodiment.

As illustrated in <FIG>, the sensor pixel 110B according to the present modification example is such that the TG <NUM> further includes a trench gate <NUM> serving as a third trench gate in addition to the trench gate <NUM> and the trench gate <NUM>. Further, the trench gates <NUM> to <NUM> each have a cross-section along the XY plane of a substantially square shape. Still further, in the XY plane, a distance between the trench gate <NUM> and the FD <NUM>, which is the transfer destination, is shorter than a distance between the trench gate <NUM> and the FD <NUM>, and is shorter than a distance between the trench gate <NUM> and the FD <NUM>. Except for these points, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above.

As described above, according to the sensor pixel 110B of the present modification example, the trench gate <NUM> is further provided, and thus the number of trench gates is large compared to the sensor pixel <NUM>. Therefore, it is possible to exert a modulation force also on a potential of a region at a position farther from the TG <NUM> in the horizontal plane (in the XY plane) of the PD <NUM>. As a result, it is possible to more smoothly transfer the electric charges from the PD <NUM> to the FD <NUM>.

<FIG> is a plan view of a sensor pixel 110C according to a fifth modification example of the first embodiment. It is to be noted that <FIG> corresponds to <FIG> of the first embodiment.

As illustrated in <FIG>, in the sensor pixel 110C according to the present modification example, the TG <NUM> further includes the trench gate <NUM> serving as the third trench gate in addition to the trench gate <NUM> and the trench gate <NUM>. Further, the trench gates <NUM> to <NUM> each have a cross-section along the XY plane of a substantially square shape. Still further, in the XY plane, a distance between the trench gate <NUM> and the FD <NUM>, which is the transfer destination, is longer than a distance between the trench gate <NUM> and the FD <NUM>, and is longer than a distance between the trench gate <NUM> and the FD <NUM>. Except for these points, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above.

As described above, according to the sensor pixel 110C of the present modification example, the trench gate <NUM> is further provided, and thus the number of trench gates is large compared to the sensor pixel <NUM>. Therefore, it is possible to exert a modulation force also on a potential of a region at a position farther from the TG <NUM> in the horizontal plane of the PD <NUM> (in the XY plane). As a result, it is possible to more smoothly transfer the electric charges from the PD <NUM> to the FD <NUM>. Further, in the sensor pixel 110C according to the present modification example, two out of the three trench gates are disposed in the vicinity of the FD <NUM> which is the transfer destination of electric charges. This makes it possible to more efficiently transfer the electric charges of the PD <NUM> to the FD <NUM> as compared with the sensor pixel 110B according to the fourth modification example of the first embodiment illustrated in <FIG>. This is because a favorable transfer path that allows more efficient transfer of the electric charges of the PD <NUM>, i.e., a region portion between the trench gate <NUM> and the trench gate <NUM>, is disposed in the vicinity of the FD <NUM>.

<FIG> is a plan view of a sensor pixel 110D according to a sixth modification example of the first embodiment. It is to be noted that <FIG> corresponds to <FIG> of the first embodiment.

As illustrated in <FIG>, the sensor pixel 110D according to the present modification example has the trench gates <NUM> and <NUM> each having a cross-section along the XY plane of a substantially square shape. Except for this point, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above.

As described above, according to the sensor pixel 110D of the present modification example, it is possible to decrease an area occupied by the TG <NUM> in the horizontal plane (in the XY plane) as compared with the sensor pixel <NUM> according to the first embodiment described above. Therefore, it is possible to increase a light-receivable area of the PD <NUM> in the horizontal plane (in the XY plane).

<FIG> is a plane configuration example of a sensor pixel <NUM> according to a second embodiment of the present technology. <FIG> is a circuit configuration example of the sensor pixel <NUM>.

The sensor pixel <NUM> according to the present embodiment is further provided with, as a transfer destination of the electric charges of the PD <NUM>, a VDD2 in addition to the FD <NUM>, and a discharge transistor (OFG) <NUM> is further provided between the PD <NUM> and the VDD2. Except for these points, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above.

The OFG <NUM> has a drain coupled to the power source VDD2 and a source coupled to a wiring line that couples the TG <NUM> to the PD <NUM>. The OFG <NUM> initializes or resets the PD <NUM> in response to a drive signal S58 applied to a gate electrode thereof. Resetting the PD <NUM> means depleting the PD <NUM>.

Further, the OFG <NUM> forms an overflow path between the TG <NUM> and the power source VDD2, and discharges electric charges overflowing from the PD <NUM> to the power source VDD2. As described above, in the sensor pixel <NUM> according to the present embodiment, the OFG <NUM> is able to directly reset the PD <NUM>, and it is possible to achieve an FD-holding global shutter.

Still further, in the present embodiment, the OFG <NUM> is also provided with a plurality of trench gates having different depths, i.e., a trench gate <NUM> and a trench gate <NUM>. Here, a length of the trench gate <NUM> and a length of the trench gate <NUM> are different from each other. As described above, in the sensor pixel <NUM> according to the present embodiment, the OFG <NUM> has the trench gate <NUM> and the trench gate <NUM> having different depths; therefore, it is possible to prevent transfer failure when the electric charges overflowing from the PD <NUM> are discharged to the power source VDD2.

<FIG> is a plane configuration example of a sensor pixel <NUM> according to a third embodiment of the present technology. <FIG> is a circuit configuration example of the sensor pixel <NUM>.

The sensor pixel <NUM> according to the present embodiment is further provided with an electric charge holding section (MEM) <NUM> between the PD <NUM> and the FD <NUM>. Accordingly, instead of the TG <NUM>, a first transfer transistor (TG) 52A and a second transfer transistor (TG) 52B are provided. The TG 52A is disposed between the PD <NUM> and the MEM <NUM>, and the TG 52B is disposed between the MEM <NUM> and the FD <NUM>. Except for these points, the rest has substantially the same configuration as the sensor pixel <NUM> according to the second embodiment described above.

In the sensor pixel <NUM> according to the present embodiment, by further providing the MEM <NUM>, the electric charges from the PD <NUM> are transferred to the MEM <NUM>, and it is possible to achieve a memory-holding global shutter. Specifically, in the sensor pixel <NUM>, when a drive signal S52A to be applied to a gate electrode of the TG 52A is turned on to turn on the TG 52A, the electric charges accumulated in the PD <NUM> are transferred to the MEM <NUM> via the TG 52A. The MEM <NUM> is an area that temporarily holds the electric charges accumulated in the PD <NUM> to achieve the global shutter function. The TG 52B is adapted to transfer the electric charges held in the MEM <NUM> to the FD <NUM> in response to a drive signal S52B applied to a gate electrode of the TG 52B. For example, when the drive signal S52 is turned off to turn off the TG 52A, and the drive signal S52B is turned on to turn off the TG 52B, the electric charges held in the MEM <NUM> are transferred to the FD <NUM> via the TG 52B.

In the sensor pixel <NUM> according to the present embodiment, the MEM <NUM> has the trench gate <NUM> and the trench gate <NUM> having different depths. Therefore, it is possible to prevent transfer failure when the electric charges are transferred to the MEM <NUM> in the PD <NUM>.

<FIG> illustrates a plane configuration example of a sensor pixel <NUM> according to a fourth embodiment of the present technology. Further, <FIG> illustrates a circuit configuration example of the sensor pixel <NUM>. Still further, <FIG> illustrates a cross-sectional configuration example of the sensor pixel <NUM>.

As illustrated in <FIG>, in the sensor pixel <NUM> according to the present embodiment, the transfer section includes a first transfer transistor (TG) 52A and a second transfer transistor (TG) 52B which are configured to be driven independently of each other. The TG 52A includes a trench gate TG <NUM> and the TG 52B has a trench gate TG <NUM>. Except for these points, the rest has substantially the same configuration as the sensor pixel <NUM> according to the first embodiment described above. Thus, in the sensor pixel <NUM>, a length L522 of the trench gate <NUM> is shorter than a length L521 of the trench gate <NUM> (L521>L522), similar to the sensor pixel <NUM>.

In the sensor pixel <NUM> according to the present embodiment, it is possible to independently drive the TG 52A and the TG 52B; therefore, it is possible to freely select an on/off drive timing in the TG 52A and an on/off drive timing in the TG 52B. Accordingly, as illustrated in <FIG>, for example, after simultaneously raising the TG 52A and the TG 52B, i.e., after simultaneously turning on the TG 52A and the TG 52B from the off state, it is possible to lower (turn off from the on state) the TG 52A prior to the TG 52B. As described above, by lowering the TG 52A before the TG 52B, a modulation force that a potential of the PD <NUM> receives from the TG <NUM> increases on the way from the back surface 11S2 side to the front surface 11S1 side along the Z-axis direction. As a result, it is possible to more effectively eliminate the potential dip in the PD <NUM> as compared with the case where two trench gates TG <NUM> and TG <NUM> are provided in one TG <NUM> as in the sensor pixel <NUM> according to the first embodiment described above.

The on/off drive timing in the TG 52A and the on/off driving timing in the TG 52B are not limited to those indicated in <FIG>, and may be as indicated in <FIG>, for example. <FIG> illustrates an example in which the TG 52A is raised before the TG 52B and the TG 52A is lowered before the TG 52B. That is, in the sensor pixel <NUM> according to the present embodiment, a period of the on state in the TG 52A and a period of the on state in the TG 52B partially overlap with each other, and the TG 52A may be lowered before the TG 52B. Alternatively, as illustrated in <FIG>, even if a timing of starting the lowering of the TG 52A coincides with a timing of starting the lowering of the TG 52B, a timing of completing the lowering of the TG 52A may be earlier than a timing of completing the lowering of the TG 52B. That is, by changing a gradient of a rate of switching from the on state to the off state, a timing of completing the switching from the on state to the off state in the TG 52B may be made later than a timing of completing the switching from the on state to the off state in the TG 52A. Pulse waveform rounding indicated in <FIG> is achievable by varying a load on the vertical driver <NUM> or a load on the horizontal driver <NUM>, or by varying a capacitance of the wiring line in the circuit illustrated in <FIG>. It is to be noted that <FIG> are each a time chart indicating waveforms of the respective drive signals supplied to the RST <NUM>, the SEL <NUM>, the TG 52A, and the TG 52B.

<FIG> is a plan view of a sensor pixel 410A according to a first modification example of the fourth embodiment. It is to be noted that <FIG> corresponds to <FIG> of the fourth embodiment.

As illustrated in <FIG>, the sensor pixel 410A according to the present modification example is such that the FD <NUM>, which is the transfer destination of the electric charges, is located between the trench gate <NUM> and the trench gate <NUM>. Except for this point, the rest has substantially the same configuration as the sensor pixel <NUM> according to the fourth embodiment described above.

As described above, according to the sensor pixel 410A of the present modification example, the FD <NUM> serving as the transfer destination is disposed between the trench gate <NUM> and the trench gate <NUM> as compared with the sensor pixel <NUM> according to the above-described fourth embodiment. In a portion between the trench gate <NUM> and the trench gate <NUM>, a back-bias effect is eliminated and the modulation force received from the TG 52A and the TG 52B is the highest. Accordingly, the electric charges to be transferred inevitably pass between the trench gate <NUM> and the trench gate <NUM> to be transferred to the front surface 11S1. The presence of the FD <NUM>, which is the transfer destination of the electric charges, in the vicinity of the front surface <NUM> enhances a transfer efficiency of the electric charges from the PD <NUM> to the FD <NUM>.

<FIG> is a plan view of a sensor pixel 410B according to a second modification example of the fourth embodiment. It is to be noted that <FIG> corresponds to <FIG> of the fourth embodiment.

As illustrated in <FIG>, in the sensor pixel 410B according to the present modification example, the TG 52A includes both of the trench gate <NUM> and the trench gate <NUM>. The TG 52B does not have a trench gate, and is located between the TG 52A and the FD <NUM>, which is the transfer destination of the electric charges. Except for this point, the rest has substantially the same configuration as the sensor pixel <NUM> according to the fourth embodiment described above.

Thus, according to the sensor pixel 410B according to the present modification example, the TG 52B having no trench gate is provided between the TG 52A having two trench gates <NUM> and <NUM> and the FD <NUM>. Accordingly, it is possible to eliminate the potential dip in the PD <NUM> while suppressing the modulation force that the potential of the PD <NUM> receives from the trench gates <NUM> and <NUM> of the TG 52A to an appropriate level. As in the sensor pixel <NUM> illustrated in <FIG> and the like, in a case where the TG 52B close to the FD <NUM>, which is the transfer destination of the electric charges, has a trench gate, the modulation force of the trench gate on the potential of the PD <NUM> may become excessively high. In such a case, when the TG 52B is switched from the on state to the off state, electrons may move from the FD <NUM> toward the trench gate. The sensor pixel 410B of the present modification example is able to effectively prevent such a backflow of electrons.

<FIG> is a plan view of a sensor pixel 410C according to a third modification example of the fourth embodiment. It is to be noted that <FIG> corresponds to <FIG> of the fourth embodiment.

As shown in <FIG>, the sensor pixel 410C according to the present modification example further includes a TG 52C which is configured to be driven independently with respect to the TG 52A and the TG 52B as a transfer section. The TG 52A includes the trench gate <NUM>, the TG 52B includes the trench gate <NUM>, and the TG 52C includes a trench gate <NUM>. Except for this point, the rest has substantially the same configuration as the sensor pixel <NUM> according to the fourth embodiment described above.

As described above, according to the sensor pixel 410C of the present modification example, the TG 52C is further provided; therefore, it is possible to more smoothly transfer the electric charges from the PD <NUM> in the horizontal plane (XY plane) as compared with the sensor pixel <NUM>. Accordingly, for example, it is possible to easily increase a saturated signal amount of the PD <NUM>.

<FIG> is a plan view of a sensor pixel 410D according to a fourth modification example of the fourth embodiment. It is to be noted that <FIG> corresponds to <FIG> of the fourth embodiment.

As illustrated in <FIG>, in the sensor pixel 410D according to the present modification example, the TG 52C has no trench gate. Except for this point, the rest has substantially the same configuration as the sensor pixel 410C according to the third modification example of the fourth embodiment described above.

Thus, according to the sensor pixel 410D of the present modification example, the TG 52C having no trench gate is provided between the TG 52A and the TG 52B and the FD <NUM> having the trench gates <NUM> and <NUM>, respectively. Accordingly, it is possible to eliminate the potential dip in the PD <NUM> while suppressing the modulation force that the potential of the PD <NUM> receives from each of the trench gate <NUM> of the TG 52A and the trench gate <NUM> of the TG 52B to an appropriate level.

<FIG> is a block diagram illustrating a configuration example of a camera <NUM> which is an electronic apparatus to which the present technology is applied.

The camera <NUM> includes: an optical unit <NUM> including a lens group, etc.; an imaging device <NUM> to which the above-described solid-state imaging device <NUM> or the like (hereinafter referred to as the solid-state imaging device <NUM> or the like) is applied; and a DSP (Digital Signal Processor) circuit <NUM> which is a camera signal processing circuit. The camera <NUM> also includes a frame memory <NUM>, a display <NUM>, a recorder <NUM>, an operation unit <NUM>, and a power source unit <NUM>. The DSP circuit <NUM>, the frame memory <NUM>, the display <NUM>, the recorder <NUM>, the operation unit <NUM>, and the power source unit <NUM> are coupled to each other via a bus line <NUM>.

The optical unit <NUM> takes in entering light (image light) from a subject and forms an image on an imaging plane of the imaging device <NUM>. The imaging device <NUM> converts a light amount of the entering light, which is formed into the image on the imaging plane by the optical unit <NUM>, to an electric signal on a pixel-unit basis, and outputs the electric signal as a pixel signal.

The display <NUM> includes, for example, a panel display device such as a liquid crystal panel or an organic EL panel. The display <NUM> displays, for example, a moving image or a still image captured by the imaging device <NUM>. The recorder <NUM> causes the moving image or the still image captured by the imaging device <NUM> to be recorded in a recording medium such as a hard disk or a semiconductor memory.

The operation unit <NUM> outputs an operation command regarding a variety of functions of the camera <NUM> under operation by a user. The power source unit <NUM> appropriately supplies a variety of power sources to serve as respective operation power sources for the DSP circuit <NUM>, the frame memory <NUM>, the display <NUM>, the recorder <NUM>, and the operation unit <NUM>, to these targets of supply.

As described above, the use of the above-described solid-state imaging device 101A or the like as the imaging device <NUM> leads to an expectation of acquiring a favorable image.

The technology according to the present disclosure (present technology) is applicable to a variety of products. For example, the technology according to the present disclosure may be achieved as a device mounted on any type of mobile body such as a vehicle, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a vessel, a robot, and the like.

The vehicle control system <NUM> includes a plurality of electronic control units connected to each other via a communication network <NUM>. In the example depicted in FIG. <NUM>, the vehicle control system <NUM> includes a driving system control unit <NUM>, a body system control unit <NUM>, an outside-vehicle information detecting unit <NUM>, an in-vehicle information detecting unit <NUM>, and an integrated control unit <NUM>. In addition, a microcomputer <NUM>, a sound/image output section <NUM>, and a vehicle-mounted network interface (I/F) <NUM> are illustrated as a functional configuration of the integrated control unit <NUM>.

The outside-vehicle information detecting unit <NUM> detects information about the outside of the vehicle including the vehicle control system <NUM>. For example, the outside-vehicle information detecting unit <NUM> is connected with an imaging section <NUM>. The outside-vehicle information detecting unit <NUM> makes the imaging section <NUM> image an image of the outside of the vehicle, and receives the imaged image. On the basis of the received image, the outside-vehicle information detecting unit <NUM> may perform processing of detecting an object such as a human, a vehicle, an obstacle, a sign, a character on a road surface, or the like, or processing of detecting a distance thereto.

The imaging section <NUM> is an optical sensor that receives light, and which outputs an electric signal corresponding to a received light amount of the light. The imaging section <NUM> can output the electric signal as an image, or can output the electric signal as information about a measured distance. In addition, the light received by the imaging section <NUM> may be visible light, or may be invisible light such as infrared rays or the like.

In addition, the microcomputer <NUM> can output a control command to the body system control unit <NUM> on the basis of the information about the outside of the vehicle which information is obtained by the outside-vehicle information detecting unit <NUM>. For example, the microcomputer <NUM> can perform cooperative control intended to prevent a glare by controlling the headlamp so as to change from a high beam to a low beam, for example, in accordance with the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detecting unit <NUM>.

The sound/image output section <NUM> transmits an output signal of at least one of a sound and an image to an output device capable of visually or auditorily notifying information to an occupant of the vehicle or the outside of the vehicle. In the example of <FIG>, an audio speaker <NUM>, a display section <NUM>, and an instrument panel <NUM> are illustrated as the output device. The display section <NUM> may, for example, include at least one of an on-board display and a head-up display.

The imaging sections <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are, for example, disposed at positions on a front nose, sideview mirrors, a rear bumper, and a back door of the vehicle <NUM> as well as a position on an upper portion of a windshield within the interior of the vehicle. The imaging section <NUM> provided to the front nose and the imaging section <NUM> provided to the upper portion of the windshield within the interior of the vehicle obtain mainly an image of the front of the vehicle <NUM>. The imaging sections <NUM> and <NUM> provided to the sideview mirrors obtain mainly an image of the sides of the vehicle <NUM>. The imaging section <NUM> provided to the rear bumper or the back door obtains mainly an image of the rear of the vehicle <NUM>. The imaging section <NUM> provided to the upper portion of the windshield within the interior of the vehicle is used mainly to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, or the like.

Incidentally, FIG. <NUM> depicts an example of photographing ranges of the imaging sections <NUM> to <NUM>. An imaging range <NUM> represents the imaging range of the imaging section <NUM> provided to the front nose. Imaging ranges <NUM> and <NUM> respectively represent the imaging ranges of the imaging sections <NUM> and <NUM> provided to the sideview mirrors. An imaging range <NUM> represents the imaging range of the imaging section <NUM> provided to the rear bumper or the back door. A bird's-eye image of the vehicle <NUM> as viewed from above is obtained by superimposing image data imaged by the imaging sections <NUM> to <NUM>, for example.

At least one of the imaging sections <NUM> to <NUM> may have a function of obtaining distance information. For example, at least one of the imaging sections <NUM> to <NUM> may be a stereo camera constituted of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, the microcomputer <NUM> can determine a distance to each three-dimensional object within the imaging ranges <NUM> to <NUM> and a temporal change in the distance (relative speed with respect to the vehicle <NUM>) on the basis of the distance information obtained from the imaging sections <NUM> to <NUM>, and thereby extract, as a preceding vehicle, a nearest three-dimensional object in particular that is present on a traveling path of the vehicle <NUM> and which travels in substantially the same direction as the vehicle <NUM> at a predetermined speed (for example, equal to or more than <NUM>/hour). Further, the microcomputer <NUM> can set a following distance to be maintained in front of a preceding vehicle in advance, and perform automatic brake control (including following stop control), automatic acceleration control (including following start control), or the like. It is thus possible to perform cooperative control intended for automatic driving that makes the vehicle travel autonomously without depending on the operation of the driver or the like.

In the forgoing, described is one example of the vehicle control system to which the technology according to the present disclosure is applicable. The technology according to the present disclosure is applicable to the imaging section <NUM> among the above-described components. Specifically, the solid-state imaging device 101A illustrated in <FIG>, etc. or the like is applicable to the imaging section <NUM>. The application of the technology according to the present disclosure to the imaging section <NUM> leads to an expectation of a superior operation of the vehicle control system.

The technology (the present technology) according to the present disclosure is applicable to a variety of products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

<FIG> is a view depicting an example of a schematic configuration of an endoscopic surgery system to which the technology according to an embodiment of the present disclosure (present technology) can be applied.

In <FIG>, a state is illustrated in which a surgeon (medical doctor) <NUM> is using an endoscopic surgery system <NUM> to perform surgery for a patient <NUM> on a patient bed <NUM>. As depicted, the endoscopic surgery system <NUM> includes an endoscope <NUM>, other surgical tools <NUM> such as a pneumoperitoneum tube <NUM> and an energy device <NUM>, a supporting arm apparatus <NUM> which supports the endoscope <NUM> thereon, and a cart <NUM> on which various apparatus for endoscopic surgery are mounted.

The endoscope <NUM> includes a lens barrel <NUM> having a region of a predetermined length from a distal end thereof to be inserted into a body cavity of the patient <NUM>, and a camera head <NUM> connected to a proximal end of the lens barrel <NUM>. In the example depicted, the endoscope <NUM> is depicted which includes as a rigid endoscope having the lens barrel <NUM> of the hard type. However, the endoscope <NUM> may otherwise be included as a flexible endoscope having the lens barrel <NUM> of the flexible type.

The lens barrel <NUM> has, at a distal end thereof, an opening in which an objective lens is fitted. A light source apparatus <NUM> is connected to the endoscope <NUM> such that light generated by the light source apparatus <NUM> is introduced to a distal end of the lens barrel <NUM> by a light guide extending in the inside of the lens barrel <NUM> and is irradiated toward an observation target in a body cavity of the patient <NUM> through the objective lens. It is to be noted that the endoscope <NUM> may be a forward-viewing endoscope or may be an oblique-viewing endoscope or a side-viewing endoscope.

An optical system and an image pickup element are provided in the inside of the camera head <NUM> such that reflected light (observation light) from the observation target is condensed on the image pickup element by the optical system. The observation light is photo-electrically converted by the image pickup element to generate an electric signal corresponding to the observation light, namely, an image signal corresponding to an observation image. The image signal is transmitted as RAW data to a CCU <NUM>.

The CCU <NUM> includes a central processing unit (CPU), a graphics processing unit (GPU) or the like and integrally controls operation of the endoscope <NUM> and a display apparatus <NUM>. Further, the CCU <NUM> receives an image signal from the camera head <NUM> and performs, for the image signal, various image processes for displaying an image based on the image signal such as, for example, a development process (demosaic process).

The display apparatus <NUM> displays thereon an image based on an image signal, for which the image processes have been performed by the CCU <NUM>, under the control of the CCU <NUM>.

The light source apparatus <NUM> includes a light source such as, for example, a light emitting diode (LED) and supplies irradiation light upon imaging of a surgical region to the endoscope <NUM>.

An inputting apparatus <NUM> is an input interface for the endoscopic surgery system <NUM>. A user can perform inputting of various kinds of information or instruction inputting to the endoscopic surgery system <NUM> through the inputting apparatus <NUM>. For example, the user would input an instruction or a like to change an image pickup condition (type of irradiation light, magnification, focal distance or the like) by the endoscope <NUM>.

A treatment tool controlling apparatus <NUM> controls driving of the energy device <NUM> for cautery or incision of a tissue, sealing of a blood vessel or the like. A pneumoperitoneum apparatus <NUM> feeds gas into a body cavity of the patient <NUM> through the pneumoperitoneum tube <NUM> to inflate the body cavity in order to secure the field of view of the endoscope <NUM> and secure the working space for the surgeon. A recorder <NUM> is an apparatus capable of recording various kinds of information relating to surgery. A printer <NUM> is an apparatus capable of printing various kinds of information relating to surgery in various forms such as a text, an image or a graph.

It is to be noted that the light source apparatus <NUM> which supplies irradiation light when a surgical region is to be imaged to the endoscope <NUM> may include a white light source which includes, for example, an LED, a laser light source or a combination of them. Where a white light source includes a combination of red, green, and blue (RGB) laser light sources, since the output intensity and the output timing can be controlled with a high degree of accuracy for each color (each wavelength), adjustment of the white balance of a picked up image can be performed by the light source apparatus <NUM>. Further, in this case, if laser beams from the respective RGB laser light sources are irradiated time-divisionally on an observation target and driving of the image pickup elements of the camera head <NUM> are controlled in synchronism with the irradiation timings. Then images individually corresponding to the R, G and B colors can be also picked up time-divisionally. According to this method, a color image can be obtained even if color filters are not provided for the image pickup element.

Further, the light source apparatus <NUM> may be controlled such that the intensity of light to be outputted is changed for each predetermined time. By controlling driving of the image pickup element of the camera head <NUM> in synchronism with the timing of the change of the intensity of light to acquire images time-divisionally and synthesizing the images, an image of a high dynamic range free from underexposed blocked up shadows and overexposed highlights can be created.

Further, the light source apparatus <NUM> may be configured to supply light of a predetermined wavelength band ready for special light observation. In special light observation, for example, by utilizing the wavelength dependency of absorption of light in a body tissue to irradiate light of a narrow band in comparison with irradiation light upon ordinary observation (namely, white light), narrow band observation (narrow band imaging) of imaging a predetermined tissue such as a blood vessel of a superficial portion of the mucous membrane or the like in a high contrast is performed. Alternatively, in special light observation, fluorescent observation for obtaining an image from fluorescent light generated by irradiation of excitation light may be performed. In fluorescent observation, it is possible to perform observation of fluorescent light from a body tissue by irradiating excitation light on the body tissue (autofluorescence observation) or to obtain a fluorescent light image by locally injecting a reagent such as indocyanine green (ICG) into a body tissue and irradiating excitation light corresponding to a fluorescent light wavelength of the reagent upon the body tissue. The light source apparatus <NUM> can be configured to supply such narrow-band light and/or excitation light suitable for special light observation as described above.

<FIG> is a block diagram depicting an example of a functional configuration of the camera head <NUM> and the CCU <NUM> depicted in <FIG>.

The camera head <NUM> includes a lens unit <NUM>, an image pickup unit <NUM>, a driving unit <NUM>, a communication unit <NUM> and a camera head controlling unit <NUM>. The CCU <NUM> includes a communication unit <NUM>, an image processing unit <NUM> and a control unit <NUM>. The camera head <NUM> and the CCU <NUM> are connected for communication to each other by a transmission cable <NUM>.

The lens unit <NUM> is an optical system, provided at a connecting location to the lens barrel <NUM>. Observation light taken in from a distal end of the lens barrel <NUM> is guided to the camera head <NUM> and introduced into the lens unit <NUM>. The lens unit <NUM> includes a combination of a plurality of lenses including a zoom lens and a focusing lens.

The image pickup unit <NUM> includes an image pickup element. The number of image pickup elements which is included by the image pickup unit <NUM> may be one (single-plate type) or a plural number (multi-plate type). Where the image pickup unit <NUM> is configured as that of the multi-plate type, for example, image signals corresponding to respective R, G and B are generated by the image pickup elements, and the image signals may be synthesized to obtain a color image. The image pickup unit <NUM> may also be configured so as to have a pair of image pickup elements for acquiring respective image signals for the right eye and the left eye ready for three dimensional (3D) display. If 3D display is performed, then the depth of a living body tissue in a surgical region can be comprehended more accurately by the surgeon <NUM>. It is to be noted that, where the image pickup unit <NUM> is configured as that of stereoscopic type, a plurality of systems of lens units <NUM> are provided corresponding to the individual image pickup elements.

Further, the image pickup unit <NUM> may not necessarily be provided on the camera head <NUM>. For example, the image pickup unit <NUM> may be provided immediately behind the objective lens in the inside of the lens barrel <NUM>.

The driving unit <NUM> includes an actuator and moves the zoom lens and the focusing lens of the lens unit <NUM> by a predetermined distance along an optical axis under the control of the camera head controlling unit <NUM>. Consequently, the magnification and the focal point of a picked up image by the image pickup unit <NUM> can be adjusted suitably.

The communication unit <NUM> includes a communication apparatus for transmitting and receiving various kinds of information to and from the CCU <NUM>. The communication unit <NUM> transmits an image signal acquired from the image pickup unit <NUM> as RAW data to the CCU <NUM> through the transmission cable <NUM>.

In addition, the communication unit <NUM> receives a control signal for controlling driving of the camera head <NUM> from the CCU <NUM> and supplies the control signal to the camera head controlling unit <NUM>. The control signal includes information relating to image pickup conditions such as, for example, information that a frame rate of a picked up image is designated, information that an exposure value upon image picking up is designated and/or information that a magnification and a focal point of a picked up image are designated.

It is to be noted that the image pickup conditions such as the frame rate, exposure value, magnification or focal point may be designated by the user or may be set automatically by the control unit <NUM> of the CCU <NUM> on the basis of an acquired image signal. In the latter case, an auto exposure (AE) function, an auto focus (AF) function and an auto white balance (AWB) function are incorporated in the endoscope <NUM>.

The camera head controlling unit <NUM> controls driving of the camera head <NUM> on the basis of a control signal from the CCU <NUM> received through the communication unit <NUM>.

The communication unit <NUM> includes a communication apparatus for transmitting and receiving various kinds of information to and from the camera head <NUM>. The communication unit <NUM> receives an image signal transmitted thereto from the camera head <NUM> through the transmission cable <NUM>.

Further, the communication unit <NUM> transmits a control signal for controlling driving of the camera head <NUM> to the camera head <NUM>. The image signal and the control signal can be transmitted by electrical communication, optical communication or the like.

The image processing unit <NUM> performs various image processes for an image signal in the form of RAW data transmitted thereto from the camera head <NUM>.

The control unit <NUM> performs various kinds of control relating to image picking up of a surgical region or the like by the endoscope <NUM> and display of a picked up image obtained by image picking up of the surgical region or the like. For example, the control unit <NUM> creates a control signal for controlling driving of the camera head <NUM>.

Further, the control unit <NUM> controls, on the basis of an image signal for which image processes have been performed by the image processing unit <NUM>, the display apparatus <NUM> to display a picked up image in which the surgical region or the like is imaged. Thereupon, the control unit <NUM> may recognize various objects in the picked up image using various image recognition technologies. For example, the control unit <NUM> can recognize a surgical tool such as forceps, a particular living body region, bleeding, mist when the energy device <NUM> is used and so forth by detecting the shape, color and so forth of edges of objects included in a picked up image. The control unit <NUM> may cause, when it controls the display apparatus <NUM> to display a picked up image, various kinds of surgery supporting information to be displayed in an overlapping manner with an image of the surgical region using a result of the recognition. Where surgery supporting information is displayed in an overlapping manner and presented to the surgeon <NUM>, the burden on the surgeon <NUM> can be reduced and the surgeon <NUM> can proceed with the surgery with certainty.

The transmission cable <NUM> which connects the camera head <NUM> and the CCU <NUM> to each other is an electric signal cable ready for communication of an electric signal, an optical fiber ready for optical communication or a composite cable ready for both of electrical and optical communications.

Here, while, in the example depicted, communication is performed by wired communication using the transmission cable <NUM>, the communication between the camera head <NUM> and the CCU <NUM> may be performed by wireless communication.

The above has described the example of the endoscopic surgery system to which the technology according to the present disclosure may be applied. The technology according to the present disclosure may be applied to (the image processing unit <NUM> of) the CCU <NUM> or the like among the above-described components. Specifically, for example, the solid-state imaging device 101A of <FIG> may be applied to the image pickup unit <NUM>. Applying the technology according to the present disclosure to the image pickup unit <NUM> enables to acquire a clearer image of the surgical region and thereby making it possible for the surgeon to confirm the surgical region with certainty.

It is to be noted that the endoscopic surgery system has been described here as an example, but the technology according to the present disclosure may be additionally applied, for example, to a microscopic surgery system or the like.

Although the present disclosure has been described with reference to some embodiments and modification examples, the present disclosure is not limited to the above embodiments and the like, and may be modified in a variety of ways. For example, in the above embodiments and the like, the global shutter mode backside illumination image sensor has been exemplified, but the imaging device according to the present disclosure is not limited thereto, and may be an image sensor of another type. That is, the present disclosure is not limited to the global shutter mode image sensor, and is also applicable to a rolling shutter image sensor. Further, the present disclosure is not limited to the backside illumination image sensor, and is also applicable to a front-side illumination image sensor. In addition, the technique of the present disclosure is not limited to the application to the CMOS image sensors, and is applicable to every solid-state imaging device of an X-Y addressing method in which unit pixels are arranged two-dimensionally in a matrix.

Further, the imaging device according to the present disclosure is not limited to the imaging device that detects a light amount distribution of visible light and acquires the light amount distribution as an image, and may be an imaging device that acquires a distribution of an amount of entering infrared rays, X-rays, particles, or the like as an image.

Further, the imaging device according to the present disclosure may be in a form of a module in which the imaging section and the signal processor or the optical system are packaged together.

In the above embodiments and the like, the sensor pixels each including, as the transfer sections, two or three transfer transistors separated from each other are exemplified, but the imaging device according to the present disclosure may have four or more transfer transistors as the transfer sections.

This application claims the benefit of Japanese Priority Patent Application <CIT>.

Claim 1:
An imaging device (<NUM>, 101A, 101B, 101C) comprising:
a semiconductor layer (<NUM>) having a front surface (11S1) and a back surface (11S2), the back surface being on an opposite side of the front surface;
a photoelectric converter (<NUM>) that is embedded in the semiconductor layer and generates electric charges corresponding to a received light amount; and
a transfer section (<NUM>) that includes a first trench gate (<NUM>) and a second trench gate (<NUM>) and transfers the electric charges from the photoelectric converter to a single transfer destination (<NUM>) via the first trench gate and the second trench gate, the first trench gate and the second trench gate each extending from the front surface to the back surface of the semiconductor layer into the photoelectric converter, wherein
the first trench gate has a first length (L521) from the front surface to the photoelectric converter, and
the second trench gate has a second length (L522) from the front surface to the photoelectric converter, the second length being shorter than the first length,
wherein, in a plane parallel to the front surface, a distance between the second trench gate and the transfer destination is shorter than a distance between the first trench gate and the transfer destination.