JP2007329554A - Photoelectric conversion film lamination type solid-state imaging element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion film lamination type solid-state imaging element of a hybrid type capable of imaging a bright image excellent in image quality even in the case of photographing incapable of using a flash light and even in the case of moving picture photographing or the like. <P>SOLUTION: The photoelectric conversion film lamination type solid-state imaging element with a configuration wherein a photoelectric conversion film detects a first color light in three primary color lights and photodiodes detect the second and third color lights, includes an output signal processing section 24 comprising: signal memory means 58, 59 provided to each pixel column composed of unit pixels and for storing signals read from color pixels of the same color adjacent to each other in the same unit pixel row; and a row direction scanning control means 54 that switches between a full pixel read operation for individually reading the signals stored in the signal memory means 58, 59 and outputting externally the read signals and a summation reading operation for simultaneously reading the signals in the signal memory means 58, 59 adjacent by each pixel column among the signals stored in the signal memory means 58, 59 and externally outputting the read signals. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a photoelectric conversion film in which incident light of one of the three primary colors is received by a photoelectric conversion film laminated on a semiconductor substrate and the remaining two colors of incident light transmitted through the photoelectric conversion film are formed on the semiconductor substrate. The present invention relates to a photoelectric conversion film stacked solid-state image pickup device that receives light with an element (photodiode), and more particularly to a signal photoelectric conversion film stacked solid-state image pickup device that can obtain an image with good image quality even in a dark scene.

  In a single-plate color solid-state imaging device typified by a CMOS image sensor, three or four color filters are arranged in a mosaic pattern on a large number of photoelectric conversion pixels arrayed on a semiconductor substrate. Thereby, a color signal corresponding to the color filter is output from each pixel, and a color image is generated by performing signal processing on these color signals.

  However, in a color solid-state imaging device in which color filters are arranged in a mosaic shape, about 2/3 of incident light is absorbed by the color filter in the case of a primary color filter, light use efficiency is poor and sensitivity is low. There's a problem. Further, since only one color signal can be obtained for each pixel, the resolution is poor, and in particular, there is a problem that false colors are conspicuous.

  In order to overcome such a problem, an image sensor having a structure in which a three-layer photoelectric conversion film is stacked on a semiconductor substrate on which a signal readout circuit is formed has been researched and developed (for example, the following patent document). 1, 2). For example, the imaging element is a pixel in which a photoelectric conversion film that generates signal charges (electrons or holes) is superimposed on blue (B), green (G), and red (R) light sequentially from a light incident surface. A signal readout circuit having a structure and capable of independently reading out signal charges generated by light in each photoelectric conversion film is provided for each pixel.

  In the case of an image pickup device having such a structure, incident light is almost photoelectrically converted and read out, the use efficiency of visible light is close to 100%, and color signals of three colors of R, G, and B are obtained in each pixel. Therefore, it is possible to generate a good image with high sensitivity and high resolution (false colors are not noticeable).

  In addition, in the image sensor described in Patent Document 3 below, a triple well (photodiode) for detecting an optical signal is provided in a silicon substrate, and signals (surfaces) having different spectral sensitivities due to differences in the depth of the silicon substrate. To B (blue), G (green), and R (red) wavelengths. This utilizes the fact that the penetration distance of incident light into the silicon substrate depends on the wavelength. Similarly to the image sensors described in Patent Documents 1 and 2, this image sensor can obtain a good image with high sensitivity and high resolution (false colors are not noticeable).

  However, the imaging devices described in Patent Documents 1 and 2 sequentially stack three layers of photoelectric conversion films on a semiconductor substrate, and the signal charges generated for each of the photoelectric conversion films for each of R, G, and B are obtained. It is necessary to form vertical wirings connected to the signal readout circuits formed on the semiconductor substrates, respectively, which are difficult to manufacture and have a problem that the manufacturing yield is low and the cost increases.

  On the other hand, the imaging device described in Patent Document 3 has a structure in which blue light is detected by the shallowest photodiode, red light is detected by the deepest photodiode, and green light is detected by the intermediate photodiode. For example, in the shallowest photodiode, photoelectric charge is generated even by green light or red light, so that the spectral sensitivity characteristics of the R signal, G signal, and B signal are not sufficiently separated. Therefore, in order to obtain a true R signal, G signal, and B signal, it is necessary to add / subtract the output signal from each photodiode, the calculation load is high, and the S / N of the image signal is reduced by this addition / subtraction process. The problem of deteriorating arises.

  An image sensor described in Patent Document 4 has been proposed to improve each of the problems of the image sensors described in Patent Documents 1, 2, and 3. This image pickup device is a hybrid type of the image pickup device described in Patent Documents 1 and 2 and the image pickup device described in Patent Document 3, and the structure thereof is a semiconductor including only one layer of a photoelectric conversion film having sensitivity to green (G). The blue (B) and red (R) incident light, which is stacked on the substrate and transmitted through the photoelectric conversion film, is received by two photodiodes formed in the depth direction of the semiconductor substrate, as in the conventional image sensor. It has a structure to do.

  That is, the hybrid color solid-state imaging device has a blue detection photodiode (each of which a plurality of unit pixels arranged in a two-dimensional array on the surface of the semiconductor substrate are formed in the depth direction of the semiconductor substrate ( Photoelectric conversion element: hereinafter referred to as B pixel) and red detection photodiode (photoelectric conversion element: hereinafter referred to as R pixel), and green detection photoelectric conversion film (hereinafter referred to as G pixel) laminated on the semiconductor substrate surface. Said). Since each unit pixel includes an R pixel 1, a B pixel 2 and a G pixel 3 as shown in FIG. 10, there are also three signal readout circuits 4, 5, and 6 for reading out each color signal to the outside. Is provided.

  As the signal readout circuit (charge detection circuit), a known signal readout circuit used in a conventional CMOS image sensor can be used as it is. This signal readout circuit is composed of transistors, and is composed of three transistors (output transistor 11, row selection transistor 12, reset transistor 13) shown in FIG. 11 (a), and 4 shown in FIG. 11 (b). Some transistors (output transistor 11, row selection transistor 12, reset transistor 13, read transistor 14) are included.

  Since the hybrid photoelectric conversion film stacked color solid-state imaging device having such a configuration requires only one photoelectric conversion film, the manufacturing process is simplified, and an increase in cost and a decrease in yield can be avoided. In addition, since green light is absorbed by the photoelectric conversion film, the separation of spectral sensitivity characteristics of the blue and red photodiodes in the semiconductor substrate is improved, color reproducibility is improved, and S / N is also improved. In addition, there is an advantage that a highly sensitive image can be taken because there is no wasted light and the light use efficiency is high.

Special Table 2002-502120 JP 2002-83946 A JP-T-2002-513145 JP 2003-332551 A

  In a camera using a high-resolution image sensor, a still image is shot at a high resolution comparable to a silver salt film, and a moving image is shot at a low resolution equivalent to a television at 30 frames / second. In the case of an image sensor with more than 2 million pixels, it is difficult to read out color signals of all pixels in 1/30 seconds.

  For this reason, in a camera using a conventional CCD image sensor or CMOS image sensor, when capturing a still image, the color signals of all the pixels are read out to generate still image data. By selecting only the row and reading out only the pixel signal of the selected pixel row, it is possible to realize shooting at 30 frames / second.

  When this moving image shooting method is applied to a hybrid type photoelectric conversion film stacked color solid-state imaging device capable of performing high-sensitivity shooting with high light utilization efficiency, pixel signals in unselected pixel rows do not contribute to moving images. There is a problem that the substantial sensitivity is lowered.

  In addition, when a still image is picked up using a hybrid photoelectric conversion film stacked color solid-state image pickup device, the flash light built in the camera emits light so that a good image quality, that is, S / N is good even in a dark scene. A still image can be taken. However, since the flash light cannot be used when shooting a moving image, the image quality of the moving image in a dark scene becomes very poor.

  Furthermore, even when shooting still images of dark scenes, when shooting in places where flash light emission is prohibited, or when shooting distant scenes where flash light does not reach, captured images are taken in the same way as for moving images. The image quality will deteriorate.

  An object of the present invention is to provide a hybrid type photoelectric conversion film laminated solid-state imaging device capable of obtaining an image with good image quality even in a dark scene.

In the photoelectric conversion film laminated solid-state imaging device of the present invention, a plurality of unit pixels are arranged and formed in a two-dimensional array on the surface portion of the semiconductor substrate, and each unit pixel has three primary colors, a first color, a second color, and a third color. Composed of a first color pixel, a second color pixel, and a third color pixel that detect each incident light amount of the color, and the first color pixel is composed of a photoelectric conversion film laminated on a surface portion of the semiconductor substrate; Each of the second color pixel and the third color pixel is composed of a photodiode formed on the surface of the semiconductor substrate, and the detection signals of the first color pixel, the second color pixel, and the third color pixel are respectively In a photoelectric conversion film laminated solid-state imaging device read by a signal readout circuit provided for each unit pixel on a semiconductor substrate,
Signal memory means for each pixel column of the unit pixels and holding each of the signals read from adjacent color pixels of the same unit pixel row, and the signal held in each of the signal memory means An all-pixel reading operation for individually reading out and outputting the signals to the outside, and an addition reading operation for simultaneously reading out the signals of the signal memory means adjacent to each pixel column among the signals held in each of the signal memory means and outputting them to the outside And an output signal processing unit having a row-direction scanning control unit that performs switching.

  The output signal processing unit of the photoelectric conversion film stacked solid-state imaging device of the present invention includes a plurality of the signal memory means provided for each of the pixel columns, and each of the plurality of signal memory means has a column direction of the unit pixel. And a memory means changeover switch for holding each of the signals read from adjacent color pixels of the same color.

  The output signal processing unit of the photoelectric conversion film stacked solid-state imaging device according to the present invention includes a first output signal processing unit for the first color pixel and a second output pixel that operates in parallel with the first output signal processing unit. And a second output signal processing unit for the third color pixel.

  In the photoelectric conversion film stacked solid-state imaging device of the present invention, the signal readout circuit that reads out the detection signal of the first color pixel is a signal readout circuit that includes a reset transistor, a row selection transistor, and an output transistor. The signal readout circuit that reads out the detection signal of the two-color pixel and the signal readout circuit that reads out the detection signal of the third color pixel are a signal readout circuit composed of a read transistor, a reset transistor, a row selection transistor, and an output transistor. It is characterized by that.

  In the photoelectric conversion film stacked solid-state imaging device of the present invention, three transistors excluding the readout transistor among the constituent transistors of the signal readout circuit that reads out the detection signal of the second color pixel receive the detection signal of the third color pixel. The configuration is characterized in that it is shared with three transistors excluding the readout transistor among the constituent transistors of the signal readout circuit to be read out, and the two readout transistors are turned on and off at different timings.

  The output signal processing unit of the photoelectric conversion film stacked solid-state imaging device according to the present invention includes an output signal of a signal reading circuit that reads a detection signal of the first color pixel, and a detection signal of the second color pixel and the third color pixel. And switching means for switching and taking in the output signal of the signal reading circuit for reading out the signal.

  The output signal processing unit of the photoelectric conversion film stacked solid-state imaging device according to the present invention includes a circuit that performs a sample hold process on the captured detection signal of the first color pixel, the captured second color pixel, and third And a circuit for performing a correlated double sampling process on the detection signal of the color pixel.

  The correlated double sample processing of the photoelectric conversion film laminated solid-state imaging device of the present invention is performed by a clamp circuit that clamps an input signal and a sample hold circuit that samples and holds the output of the clamp circuit, and the sample hold processing is performed by the clamp The circuit is bypassed by a bypass circuit and is performed by the sample hold circuit.

  In the photoelectric conversion film stacked solid-state imaging device of the present invention, after the detection signal of the first color pixel is read from the signal readout circuit to the output signal processing unit, the detection signal of the next first color pixel is not read out. Further, the reset noise signal is read out from the signal reading circuit to the output signal processing unit.

  The photoelectric conversion film stacked solid-state imaging device of the present invention has a configuration in which a row selection transistor is omitted from the signal readout circuit having the four-transistor configuration, and the applied voltage of the drain terminal of the reset transistor is variably controlled instead. It is characterized by that.

  The photoelectric conversion film laminated solid-state imaging device of the present invention is characterized in that the photoelectric conversion film has a single layer organic semiconductor structure or a multilayer organic semiconductor structure sandwiched between a transparent pixel electrode film and a counter electrode film.

  In the photoelectric conversion film laminated solid-state imaging device of the present invention, the photodiodes constituting the second color pixel and the photodiodes constituting the third color pixel are provided apart from each other in the depth direction of the semiconductor substrate. It is characterized by that.

  In the photoelectric conversion film laminated solid-state imaging device of the present invention, the first color pixel, the second color pixel, and the third color pixel each detect an incident light amount as an electron amount.

  In the photoelectric conversion film stacked solid-state imaging device of the present invention, the first color pixel detects the incident light amount by the amount of holes, and the second color pixel and the third color pixel detect the incident light amount by the amount of electrons. It is characterized by.

  The photoelectric conversion film laminated solid-state imaging device of the present invention is characterized in that an output signal of the output signal processing unit is an analog signal.

  In the photoelectric conversion film laminated solid-state imaging device of the present invention, the output signal of the output signal processing unit is a digital signal.

  In the photoelectric conversion film laminated solid-state imaging device of the present invention, the first color is green, the second color is blue, and the third color is red.

  According to the present invention, it is possible to output a captured image signal obtained by signal addition (pixel addition) at the time of shooting that cannot use flash light or moving image shooting. Can be obtained.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic view of the surface of a hybrid photoelectric conversion film laminated color solid-state imaging device according to a first embodiment of the present invention. In the photoelectric conversion film stacked solid-state imaging device 20, a plurality of unit pixels 22 are arranged in a square lattice pattern on a semiconductor substrate 21, and an output signal processing unit 24 including a row direction scanning control unit on the lower side of the semiconductor substrate 21. A column direction scanning control unit 25 is provided on the left side of the semiconductor substrate 21.

  The unit pixel 22 and the output signal processing unit 24 are connected by two column signal lines 26 and 27, and the unit pixel 22 and the column direction scanning control unit 25 are connected by four signal lines 28, 29, 30, and 31. Is done. The signal lines 28 and 29 are readout signal lines, the signal line 30 is a reset signal line, and the signal line 31 is a row selection signal line.

  FIG. 2 is a conceptual diagram of the unit pixel shown in FIG. A p well layer 35 is formed on the surface portion of the n-type semiconductor substrate 21, and n region layers 36 and 37 are formed in a deep portion and a shallow portion in the p well layer 35, respectively. The n region layer 36 and the n region layer 37 are separated from each other with the p region layer 38 interposed therebetween, and a p-type high concentration impurity surface layer 39 for suppressing dark current is provided on the outermost surface of the n region layer 37.

  A pn junction, that is, a photodiode is formed between the n region layer 36 provided in the deep surface of the semiconductor substrate 21 and the upper and lower p region layers 38 and the well layer 35, and mainly has a long wavelength that has penetrated to the deep surface. Signal charges (electrons in this example) corresponding to the amount of red light are accumulated in the n region layer 36. That is, this photodiode constitutes an R pixel.

  A pn junction, that is, a photodiode is formed between the n region layer 37 provided in the shallow portion of the semiconductor substrate 21 and the upper and lower p-type high-concentration impurity surface layers 39 and p region layer 38, and can penetrate into the deep portion of the surface. Signal charges (electrons in this example) corresponding to the amount of mainly blue light having a short wavelength that is absorbed in the shallow portion are accumulated in the n region layer 37. That is, this photodiode constitutes the B pixel.

  A transparent insulating film 41 is laminated on the surface of the semiconductor substrate 21, and a transparent pixel electrode film 42 divided for each unit pixel is laminated on the insulating layer 41, and on the pixel electrode film 42, A photoelectric conversion film 43 having a sensitivity mainly to green light having an intermediate wavelength is laminated, a transparent counter electrode film 44 provided in common to each unit pixel is provided on the photoelectric conversion film 43, and a transparent protective film is provided on the outermost surface. (Insulating film) 45 is laminated.

  The transparent electrode films 42 and 44 are formed of a material that absorbs little light. This may be a thin metal thin film or a metal compound thin film such as ITO. The counter electrode film 44 may have a single configuration common to each unit pixel, and may be provided for each pixel, or may be provided for each unit pixel column or for each unit pixel row. Wiring is performed so that one common potential can be applied to the film 44.

  The photoelectric conversion film 43 may be a single layer film structure or a multilayer film structure, and is composed of an organic semiconductor having sensitivity to green light, an organic material containing an organic dye, or the like. The photoelectric conversion film 43 generates photocharges (electron-hole pairs) corresponding to the amount of received green light, and constitutes a G pixel.

  The photoelectric conversion film stacked color solid-state imaging device of this embodiment reads a signal corresponding to a signal charge (electrons in this example) detected by a G pixel by a signal readout circuit 50 having a three-transistor configuration, and R and B pixels. The signal according to the signal charge (electrons in this example) detected by is read by the signal reading circuit 51 having a four-transistor configuration.

  In the present embodiment, in order to reduce the number of transistors, the signal readout circuit for the R pixel and the signal readout circuit for the B pixel are shared, so that the signal readout circuit 51 includes five transistors per unit pixel. When combined with the signal readout circuit 50, the number of transistors provided in one unit pixel is “8”. If there is a sufficient area, the signal readout circuit for the R pixel and the signal readout circuit for the B pixel may not be shared.

  In FIG. 2, the signal readout circuit is shown in a circuit diagram, but each MOS transistor constituting the signal readout circuit is formed on the p-well layer 35 of the semiconductor substrate 21. Although not shown in FIG. 2, the G signal charge flowing out from the pixel electrode film 42 is accumulated in a charge accumulation unit that is an impurity region formed on the semiconductor substrate 21, and the accumulation in the charge accumulation unit is performed. The signal is read out by a signal readout circuit having a three-transistor configuration. The charge storage portion and the signal readout circuit are formed in a portion covered with a light shielding film.

  The signal readout circuit 50 provided for the G pixel is the same as the circuit shown in FIG. 11B, and includes an output transistor 11, a row selection transistor 12, and a reset transistor 13.

  The output transistor 11 and the row selection transistor 12 are connected in series between the DC power supply terminal 48 and the column signal line 27, and the gate of the output transistor 11 is connected to the pixel electrode film 44 through the above-described charge storage portion of the G pixel. Then, the gate of the row selection transistor 12 is connected to the row selection signal line 31. The reset transistor 13 is provided between the DC power supply terminal 48 and the gate of the output transistor 11, and the gate of the reset transistor 13 is connected to the reset signal line 30.

  The signal readout circuit 51 is the same as the signal readout circuit 50 in the three-transistor components (output transistor 11, row selection transistor 12, and reset transistor 13), and the output transistor 11 is connected between the DC power supply terminal 48 and the column signal line 26. And the row selection transistor 12 are connected in series, and the gate of the row selection transistor 12 is connected to the row selection signal line 31. The reset transistor 13 is provided between the DC power supply terminal 48 and the gate of the output transistor 11, and the gate of the reset transistor 13 is connected to the reset signal line 30.

  A read transistor 14R is connected between the gate of the output transistor 11 and the R pixel (n region layer 36) as a switching means for turning on / off the connection between the two, and the gate of the read transistor 14R is connected to the read signal line 29. Is done. That is, the transistors 14R, 11, 12, and 13 form a four-transistor signal readout circuit for the R pixel.

  A read transistor 14B is connected between the gate of the output transistor 11 and the B pixel (n region layer 37) as a switching means for turning on and off the connection between the two, and the gate of the read transistor 14B is connected to the read signal line 28. Connected to. That is, the transistors 14B, 11, 12, and 13 form a signal readout circuit having a 4-transistor configuration for the B pixel.

  As described above, in the present embodiment, the signal readout circuit of the pixel (G pixel) using the photoelectric conversion film has a three-transistor configuration. This is because the afterimage of the G image is suppressed and the deterioration of the image quality is reduced as compared with the case where the signal readout circuit having four transistors is employed.

  In the present embodiment, the signal charge readout circuit from the pixel (R pixel, B pixel) by the photodiode formed on the semiconductor substrate in the present embodiment has a four-transistor configuration. This is because the noise can be reduced by the configuration and the image quality of the R image and the B image can be improved.

  FIG. 3 is a configuration diagram of the output signal processing unit 24. The output signal processing unit 24 includes a correlated double sampling circuit 53 provided for each unit pixel column, a row direction scanning control unit 54 that outputs a row direction scanning signal to each correlated double sampling circuit 53, and a readout output. And an output unit 55 connected to the signal line 62.

  The correlated double sampling circuit 53 is connected to column signal lines 26 and 27 common to each unit pixel row, and a switch circuit 56 that selectively connects one of the column signal lines 26 and 27 and a signal selected by the switch circuit 56. Clamp circuit 57 for clamping, two sample-and-hold (SH) circuits 58 and 59 (functioning as signal memory means), and SH selection for selecting one of the two SH circuits 58 and 59 and connecting it to the clamp circuit 56 The switch circuit 60 includes open / close switches (row direction scanning switches) 63 and 64 provided between the SH circuits 58 and 59 and the read output signal line 62. The open / close switches 63 and 64 are arranged in the row direction scanning control unit. It is opened and closed by a row direction scanning signal from 54.

  When light from a subject enters the photoelectric conversion film stacked color solid-state imaging device having such a configuration, green light in the incident light is absorbed by the photoelectric conversion film 43, and signal charges (photoelectric conversion film) are absorbed in the photoelectric conversion film 43. Electron-hole pairs are generated in this, and in this embodiment, electrons are used as signal charges). When a voltage is applied between the pixel electrode film 42 and the common electrode film 44 to form a required electric field in the photoelectric conversion film 43, the signal charge moves quickly to the pixel electrode film 42 along the electric field. In addition to being moved to and accumulated in the above-described charge accumulating unit, it is also accumulated by flowing into the gate portion of the output transistor 11 of the signal reading circuit 50.

  The mixed light of the red light and the blue light transmitted through the G pixel (photoelectric conversion film) 43 enters the semiconductor substrate 21. Of the mixed light, blue light is absorbed mainly in the shallow portion of the semiconductor substrate surface, and the generated signal charges (electrons) are accumulated in the n region layer (B pixel) 37. The red light of the mixed light penetrates to the deep surface of the semiconductor substrate 21 and is absorbed, and the generated signal charges (electrons) are accumulated in the n region layer (R pixel) 36.

  Hereinafter, an operation of reading each captured image signal from the R pixel, the G pixel, and the B pixel will be described.

[All-pixel readout operation]
The SH selection switch 60 is always set to the SH circuit 58 side. The column direction scanning control unit 25 selects a unit pixel row from which the captured image signal is read. That is, when the row selection signal is output from the column direction scanning control unit 25 to the signal line 31 of the corresponding unit pixel row, the row selection transistor 12 of this unit pixel row becomes conductive.

  Next, when the selection switch circuit 56 selects the column signal line 27, a signal corresponding to the signal charge of each G pixel in this unit pixel row is clamped by the clamp circuit 57 of each correlated double sampling circuit 53.

  Next, when a reset signal is output from the column direction scanning control unit 25 to the unit pixel row, reset noise of the G pixel is output to the column signal line 27. The sample hold circuit 58 samples and holds a signal corresponding to the signal charge of the G pixel using this reset noise signal, and holds and stores the signal.

  Next, when a row direction scanning signal is supplied from the row direction scanning control unit 54 to the opening / closing switch 63 of the unit pixel column to be read, the holding signal of the sample hold circuit 58 of this unit pixel column is read out by the readout output signal line 62. Is read out. The output unit 55 processes a signal on the read output signal line 62 and outputs an output signal corresponding to the G signal to the outside of the element. By sequentially repeating this operation for each pixel in the row direction, a signal corresponding to the G signal for each row of pixels is sequentially output to the outside of the element.

  Next, the selection switch circuit 56 is switched to select the column signal line 26, and the column signal line 26 is connected to the clamp circuit 57. Then, a reset signal is applied to the unit pixel row from the column direction scanning control unit 25, the reset noise of the B pixel is output to the column signal line 26, and the clamping operation is performed by the clamp circuit 57.

  Next, when the column direction scanning control unit 25 applies a readout signal to the B pixels in the unit pixel row, the readout transistor 14B shown in FIG. 2 is turned on (conductive). As a result, a B signal (image signal) corresponding to the signal charge of the B pixel is output to the column signal line 26, and the sample and hold circuit 58 holds and stores the signal-processed B signal.

  Next, when the row direction scanning control unit 54 outputs a row direction scanning signal to the open / close switch 63, the B signal of the sample hold circuit 58 is output to the readout output signal line 62, and the output unit 55 performs signal processing. The B signal is output outside the element. By sequentially repeating this operation for each pixel in the row direction, a signal corresponding to the B signal for each row of pixels is sequentially output to the outside of the element.

  Next, an operation similar to the operation for the B pixel is repeated for the R pixel, so that a signal corresponding to the R signal for each pixel for one row is sequentially output to the outside of the element.

  By repeating the above operation while switching the unit pixel rows to be read, the signals of the R pixel, G pixel, and B pixel for each unit pixel constituting one screen are read out to the outside of the element separately. Needless to say, the reading order of the R and B signals may be interchanged.

[Color signal addition read operation]
For example, when capturing a moving image or capturing a bright still image, in this embodiment, each G pixel signal of four adjacent unit pixels is added and read, each B pixel signal is added and read, Read by adding R pixel signals.

  Therefore, first, the column direction scanning control unit 25 selects an arbitrary (2J-1) th unit pixel row. However, “J” is a positive integer. When a row selection signal is output from the column direction scanning control unit 25 to the corresponding signal line 31, the row selection transistor 12 of this unit pixel row is turned on.

  The selection switch circuit 56 is on the column signal line 27 side, and the column signal line 26 is connected to the clamp circuit 57. Further, the SH selection switch 60 is set on the sample hold circuit 58 side.

  As a result, a G signal (image signal) corresponding to the signal charge of the G pixel is taken into the clamp circuit 57 via the column signal line 27, and a clamp operation is performed. Next, when the column direction scanning control unit 25 applies a reset signal to the unit pixel row, the reset noise of the G pixel is output to the column signal line 27, and the sample hold circuit 58 uses the reset noise signal to output the G signal. The signal is signal processed, and the G signal after the signal processing is held and stored.

  Next, the column direction scanning control unit 25 selects the (2J) th unit pixel row of the next row. Then, the SH selection switch 60 selects the SH circuit 59 side. The correlated double sampling circuit 53 takes in the G signal corresponding to the signal charge of the G pixel in the 2J-th unit pixel row and the reset noise signal in the same manner as described above, and performs signal processing to thereby obtain the 2J-th G pixel. The G signal is held and stored in the sample hold circuit 59.

  Accordingly, the sample hold circuit 58 of the left correlated double sampling circuit 53 shown in FIG. 3 has the G pixel in the (2I-1) th column and the (2J-1) th row, where I is an arbitrary positive integer. The G signal is held, and the sample hold circuit 59 holds the G signal of the G pixel in the (2I-1) th column and the (2J) th row.

  In addition, the G signal of the G pixel in the (2I) column and the (2J-1) th row is held in the sample hold circuit 58 of the correlated double sampling circuit 53 on the right side shown in FIG. , (2I) column, (2J) row G pixel G signal is held.

  Accordingly, by simultaneously reading the G signals held in the four sample hold circuits 58 and 59 shown in FIG. 3 to the read output signal line 62, each G of the four unit pixels adjacent in the column direction and adjacent in the row direction is read. The pixel signals can be added and output to the outside of the element. By repeating the operation of simultaneously reading the G signals of the four sample hold circuits 58 and 59 in the row direction, one row of the added G signals is output to the outside of the element.

  Next, the selection switch circuit 56 selects the column signal line 26 and connects it to the clamp circuit 57. The column direction scanning control unit 25 selects the (2J-1) th unit pixel row, and the SH selection switch 60 selects the SH circuit 58.

  When the column direction scanning control unit 25 applies the reset signal to the (2J-1) th unit pixel row, the reset noise of the B pixel is output to the column signal line 26, and the clamping operation is performed by the clamp circuit. Next, when the column direction scanning control unit 25 applies a readout signal for the B pixel, the readout transistor 14B is turned on, and a B signal (image signal) corresponding to the signal charge of the B pixel is output to the column signal line 26. The sample and hold circuit 58 performs a sample and hold operation. The sample and hold circuit 58 holds and stores the B signal subjected to signal processing.

  Next, the column direction scanning control unit 25 selects the 2J-th unit pixel row, and the SH selection switch 60 selects the sample hold circuit 59. When the same operation as described above is repeated, the sample and hold circuit 59 holds and stores the B signal of the 2J-th B pixel.

  In this state, the four sample and hold circuits 58 and 59 shown in FIG. 3 hold the B signals of the B pixels of the four unit pixels adjacent in the column direction and the row direction, and simultaneously receive the four B signals. By reading out to the signal line 62, the added B signal can be output to the outside of the element. By repeating the operation of simultaneously reading out the B signals of the four sample hold circuits 58 and 59 in the row direction, one row of the added B signals is output to the outside of the element.

  By performing the same operation for the R pixel as for the B pixel, a signal obtained by adding the R signals of four adjacent R pixels is output to the outside of the element.

  In the same manner, the image signal for one screen is read out by repeating the above operation for the next unit pixel rows of (2J + 1) and (2J + 2). Needless to say, the reading order of the R and B signals may be interchanged.

  As described above, in this embodiment, since the signal charges of each R pixel, G pixel, and B pixel of all the unit pixels are added and read without wasting, the flash light can be used even in a dark scene. An image with high sensitivity can be taken without using it.

(Second Embodiment)
FIG. 4 is a main part configuration diagram of an output signal processing unit used for a photoelectric conversion film laminated color solid-state imaging device according to the second embodiment of the present invention. In the correlated double sampling circuit provided in the output signal processing unit of the present embodiment, a clamp control switch circuit 67 for turning on and off the bypass path is provided in a path that bypasses the clamp circuit 57. Other configurations are the same as those of the first embodiment shown in FIGS.

  As the signal readout circuit for reading out the signal charge of the G pixel by the photoelectric conversion film, a signal readout circuit having a three-transistor configuration is employed in the first embodiment and the present embodiment. This is to reduce the afterimage of the G image. On the other hand, the signal readout circuit having the three-transistor configuration has a random noise riding on the output signal of the signal readout circuit compared to the signal readout circuit having the four-transistor configuration. There is a problem that it cannot be offset.

  This is because the reset noise for performing the correlated double sampling process is different from the reset noise included in the image signal. In other words, the reset noise included in the image signal is the reset noise one frame before, and the reset noise for performing the correlated double sampling processing is the reset noise immediately after reading the image signal. This is because the random noise contained in cannot be canceled in principle. In this embodiment, this point is improved.

  In the photoelectric conversion film stacked color solid-state imaging device of the present embodiment, when the clamp control switch circuit 67 is always opened, the clamp circuit 57 is effective, and the operation is exactly the same as that of the first embodiment. With respect to the B signal and the R signal, reset noise including random noise is eliminated in the normal correlated double sampling process, so that the signal processing of the B signal and the R signal operates in this state.

  When the clamp control switch circuit 67 is closed, the clamp circuit 57 is inoperative, and a low-noise readout operation described below can be performed. With this low-noise readout operation, an output signal corresponding to the reset noise and an output signal corresponding to the image signal including the reset noise one frame before are output for the G signal in both the all-pixel readout operation and the addition readout operation. .

  An image of the low-noise G signal is obtained by performing a subtraction process between the reset noise signal one frame before and the image signal including the reset noise one frame before outside the photoelectric conversion film stacked color solid-state imaging device. Get a signal.

[Low noise readout operation for all pixel readout]
The SH selection switch 60 always selects the SH circuit 58. When the column direction scanning control unit 25 selects a unit pixel row and outputs a row selection signal, the row selection transistor 12 in the unit pixel row is turned on.

  Next, the column signal selection switch 56 selects the column signal line 27, and the clamp control switch circuit 67 (FIG. 4) is closed.

  As a result, a G signal (image signal) corresponding to the signal charge of the G pixel is output to the column signal line 27, and the sample and hold circuit 58 performs the sample and hold operation. Reset noise including random noise one frame before is superimposed on this image signal. The G signal (image signal) is held and stored in the sample hold circuit 58 by the sample hold operation.

  Next, when a row direction scanning signal is supplied from the row direction scanning control unit 54 to the open / close switch 63, the G signal (image signal) held in the sample hold circuit 58 is read to the readout output signal line 62. The output unit 55 performs signal processing on the signal read to the read output signal line 62, and an output signal corresponding to the G signal is output to the outside of the image sensor.

  By sequentially repeating the above operation in the row direction, an output signal corresponding to the G signal for one row is output.

  Next, the column signal selection switch 56 is made to select the column signal line 26, and the clamp control switch circuit 67 is opened. Then, the same operation as the all-pixel reading operation of the first embodiment is repeated, and the B signal for one row and the R signal for one row are read out of the image sensor. Since this operation is redundantly described, the description thereof is omitted.

  Next, after reading out the B signal and the R signal to the outside of the element, the column signal selection switch 56 selects the column signal line 27 and the clamp control switch circuit 67 is opened. When a reset signal is applied to the unit pixel row from the column direction scanning control unit 25, reset noise of the G pixel in the unit pixel row is output to the column signal line 27.

  The reset noise signal is sampled and held by the sample and hold circuit 58, and the reset noise of the G pixel subjected to the signal processing is held and stored in the sample and hold circuit 58.

  Next, when the row direction scanning signal is supplied from the row direction scanning control unit 54 to the row direction scanning switch 63 and the switch 63 is closed, the reset noise signal held in the sample hold circuit 58 is supplied to the read output signal line 62. Read out. The output unit 55 performs signal processing on the signal on the readout output signal line 62 and outputs the signal to the outside of the image sensor. By sequentially repeating this operation in the row direction, an output signal corresponding to the reset noise of G pixels for one row is output.

  The above reading operation is repeated while switching the unit pixel rows to be read, and an output signal corresponding to the color signal of all pixels for one screen and an output signal corresponding to the reset noise of the G pixel are read out of the element.

  In the photoelectric conversion film stacked color solid-state imaging device of the present embodiment, the G signal read from the G pixel and stored in the frame memory provided outside is processed in the signal processing unit provided outside the device. That is, the reset noise signal one frame before stored in the frame memory and the image signal including the reset noise one frame before the G pixel are subtracted. Thereby, random noise that could not be reduced in the first embodiment can also be reduced, and the S / N of a dark subject image can be improved and a good color image can be obtained.

  The operation described above is for the case where the electronic shutter operation is not performed. When the electronic shutter operation is performed, a row selection signal and a reset signal are applied to the unit pixel row that discharges the signal charge of the G pixel by the electronic shutter, and reset noise of the unit pixel row that discharges the signal charge Read the corresponding output signal.

[Low noise readout operation during additive readout]
First, when the column direction scanning control unit 25 selects the (2J-1) th unit pixel row, the row selection transistor 12 of the unit pixel row selected by the row selection signal is turned on. The column signal selection switch 56 selects the column signal line 27 and the SH selection switch 60 selects the SH circuit 58. Further, the clamp control switch circuit 67 is closed.

  As a result, a G signal (image signal) corresponding to the signal charge of the G pixel is output to the column signal line 27, the sample hold circuit 58 performs the sample hold operation, and the G signal (G signal (G) of the G pixel in the (2J-1) row) Image signal) is held and stored in the sample and hold circuit 58.

  Next, when the column direction scanning control unit 25 selects the (2J) th unit pixel row, the row selection transistor 12 of the unit pixel row is turned on by the row selection signal. Further, the SH selection switch 60 selects the SH circuit 59.

  As a result, the G signal (image signal) corresponding to the signal charge of the G pixel in the (2J) row is output to the column signal line 27, and the G signal (image signal) subjected to the sample hold process is held and stored in the SH circuit 59. Is done.

  Next, as in the first embodiment, when four adjacent row direction scanning switches 63, 64, 63, 64 are simultaneously closed, G signals (image signals) for four pixels adjacent in the column direction and adjacent in the row direction. Are simultaneously output from the SH circuits 58, 59, 58, 59 to the read output signal line 62, added, and output to the outside of the element via the output unit 55. By repeating this operation sequentially in the row direction, the addition output signal of the G signal for one row is read out of the element and held in the external frame memory.

  Next, the unit pixel row of number (2J-1) is selected, the column signal selection switch 56 is made to select the column signal line 26, and the clamp control switch 67 is opened. Then, similarly to the first embodiment, the B signal and the R signal are read out from the element. Since the description of this operation overlaps with the description of the first embodiment, it is omitted.

  When the B signal and the R signal are read, the column direction scanning control unit 25 selects the (2J) th unit pixel row, so the column direction scanning control unit 25 next selects (2J-1). Select the unit pixel row. Further, the column signal selection switch 56 selects the column signal line 27, the clamp control switch 67 is closed, and the SH selection switch 60 selects the SH circuit 58.

  When the reset signal is applied to the unit pixel row selected by the column direction scanning control unit 25, the reset noise of the G pixel in the (2J-1) row is output to the column signal line 27, and this is sampled and held by the sample hold circuit 58. Processed, retained and stored.

  Next, the column direction scanning control unit 25 selects the (2J) th unit pixel row, and causes the SH selection switch 60 to select the SH circuit 59. When the column direction scanning control unit 25 applies the reset signal to the (2J) th unit pixel row, the reset noise of the (2J) th row G pixel is output to the column signal line 27 and the sample and hold circuit 59 performs sample and hold. Processed, retained and stored.

  Next, as in the first embodiment, when the adjacent four row direction scanning switches 63, 64, 63, 64 are simultaneously closed, the reset noise of G pixels corresponding to four pixels adjacent in the column direction and adjacent in the row direction. Signals are simultaneously output from the SH circuits 58, 59, 58, 59 to the read output signal line 62, added, and output to the outside of the element via the output unit 55. By repeating this operation sequentially in the row direction, the added output signal of the reset noise signal for one row is read out to the outside of the element and held in the external frame memory.

  The above reading operation is repeated while switching the unit pixel rows to be read, and an output signal corresponding to the color signal of all pixels for one screen and an output signal corresponding to the reset noise of the G pixel are read out of the element.

  The signal processing unit provided outside the element is configured to add a reset noise signal for four G pixels one frame before stored in the frame memory and an added image signal including a reset noise for one frame before four G pixels. And subtract. Thereby, random noise that could not be reduced in the first embodiment can also be reduced, and the S / N of a dark subject image can be improved and a good color image can be obtained.

  The operation described above is for the case where the electronic shutter operation is not performed. When the electronic shutter operation is performed, the row selection signal and the reset signal are applied to the unit pixel row from which the signal charge of the G pixel is discharged by the electronic shutter. As a result, an output signal corresponding to the reset noise of the unit pixel row to be discharged is read out.

(Third embodiment)
FIG. 5 is a schematic diagram of the entire surface of a photoelectric conversion film laminated color solid-state imaging device according to the third embodiment of the present invention. The photoelectric conversion film laminated color solid-state imaging device according to the second embodiment described above has an advantage that a G signal with good S / N can be obtained. However, in order to generate a color image of one frame, a color signal that is three times the total number of pixels (unit pixel number) is read in the first embodiment, whereas a reset noise signal is added to this in the second embodiment. Therefore, it is necessary to read a signal that is four times the total number of pixels.

  Therefore, in the second embodiment, the frame frequency cannot be increased. Therefore, the third embodiment aims to obtain a G signal with a good S / N and increase the frame frequency as in the second embodiment.

  The basic configuration of the photoelectric conversion film laminated color solid-state imaging device 70 according to this embodiment is the same as that of the second embodiment, and the same components as those shown in FIGS. The detailed explanation is omitted.

  The photoelectric conversion film stacked color solid-state imaging device 70 of the present embodiment includes two output signal processing units 23rb and 23g, a column signal line 26 is connected to the output signal processing unit 23rb, and a column signal is output to the output signal processing unit 23g. Line 27 is connected. Then, the two output signal processing units 23rb and 23g perform the signal reading process in parallel, the output signal processing unit 23rb outputs the R signal and the B signal to the outside of the imaging device, and the output signal processing unit 23g outputs the G signal to the outside of the device. Output.

  6A is a main part configuration diagram of the output signal processing unit 23g, and FIG. 6B is a main part configuration diagram of the output signal processing unit 23rb. Since the output signal processing unit 23g reads and processes the image signal and reset noise signal of the G pixel, a switch circuit 67 that opens and closes the bypass path of the clamp circuit 57 is provided in parallel with the clamp circuit 57 (note that the clamp circuit 57 itself) And the column signal line 27 may be connected to the SH selection switch 60.) Since the output signal processing unit 23rb does not read and process the image signal and reset noise signal of the R pixel and B pixel. The switch circuit 67 is not provided.

  In the photoelectric conversion film stacked color solid-state imaging device 70 of the present embodiment, the B signal (or R signal) reading process by the output signal processing unit 23rb and the G signal reading process by the output signal processing unit 23g are processed in parallel. Next, the reading process of the R signal (or B signal) by the output signal processing unit 23rb and the reading process of the reset noise signal of the G pixel by the output signal processing unit 23g are performed in parallel. Other operations are the same as those described in the second embodiment.

  According to the present embodiment, there is no need to perform a column signal line selection switch operation, and further, there is an effect that the signal can be read out at twice as fast as the second embodiment.

  In the first to third embodiments, the four open / close switches (row direction switches) 63 and 64 for performing pixel addition (color signal addition) are simultaneously opened and closed. , 64 may be configured to output each signal to the read output signal line 62 at successive timings, and this is also included in the concept of “simultaneous”.

(Fourth embodiment)
FIG. 7 is a configuration diagram of a main part of a photoelectric conversion film stacked color solid-state imaging device according to the fourth embodiment of the present invention. In the first to third embodiments, the SH selection switch 60 is provided independently of the sample and hold circuits 58 and 59, but in this embodiment, as shown in FIG. 7, the sampling transistor 58a of the sample and hold circuits 58 and 59 is provided. , 59a.

  Both output signals of the clamp circuit 57 are supplied to two sample hold circuits 58 and 59. When a sampling pulse is applied to the gate of the sampling transistor 58a, the sample hold circuit 58 performs a sample hold operation. When a sampling pulse is applied to the gate of the sampling transistor 59a, the sample hold circuit 59 performs a sample hold operation. As described above, the selection of the sample hold circuits 58 and 59 and the sample hold operation can be simultaneously processed by controlling the sampling pulse. Reference numerals 58b and 59b are capacitors.

(Fifth embodiment)
FIG. 8A is a circuit diagram of a signal readout circuit used in the photoelectric conversion film laminated color solid-state imaging device according to the fifth embodiment of the present invention. The element structure is the same as that of each of the embodiments described above, and is applied to a signal readout circuit that reads out a color image signal corresponding to a signal charge detected by a pixel (R pixel and B pixel in the above example) provided on the semiconductor substrate side. .

  In the signal readout circuit shown in FIG. 8A, the row selection transistor 12 is deleted from the signal readout circuit shown in FIG. 11B or the signal readout circuit 51 having a 4-transistor configuration shown in FIG. The signal line 26 is connected directly. Further, instead of the selection control by the row selection transistor, the potential control is performed from the column direction scanning control unit 25 on the terminal 48 connected to the drain of the output transistor 11.

  When the signal readout circuit according to the present embodiment is brought into a non-operating state, when the terminal 48 is set to a ground voltage or a low voltage and a reset signal is applied to the reset transistor 13, the output transistor 11 becomes non-conductive (off). Become. Under this state, even if the terminal 48 returns to a high voltage during normal operation, the non-operating state of the signal readout circuit is maintained.

  When this signal readout circuit is in an operating state, the terminal 48 is set to a high voltage during normal operation, and a reset signal is applied to the reset transistor 13. As a result, the output transistor 11 becomes conductive, and the signal readout circuit is in an operating state.

  Thus, since the signal readout circuit according to the present embodiment has one less transistor than the signal readout circuit having the four-transistor configuration, the circuit area of the signal readout circuit provided in the vicinity of the R pixel and the B pixel can be reduced. Therefore, the light receiving area of the R pixel and the B pixel can be increased, and the sensitivity and the saturation output voltage can be improved.

(Sixth embodiment)
FIG. 8B is a circuit diagram of a signal readout circuit used in the photoelectric conversion film laminated color solid-state imaging device according to the sixth embodiment of the present invention. The reset transistor 13 of the signal readout circuit according to the fifth embodiment is provided between the gate and the drain of the output transistor 11, whereas the reset transistor 13 of the present embodiment is provided between the gate and the source of the output transistor 11. A terminal 48 to which the drain of the output transistor 11 is connected is connected to a DC voltage.

  When the signal readout circuit according to the present embodiment is brought into a non-operating state, when the column signal line 26 is set to a ground voltage or a low voltage and a reset signal is applied to the reset transistor 13, the output transistor 11 becomes non-conductive. . Even if the color signal of another pixel row is output to the column signal line 26 based on this state, the non-operating state of the signal reading circuit is maintained.

  When the signal readout circuit is in an operating state, the voltage applied to the column signal line 26 is set to a voltage applied to the terminal 48 or a voltage close to the voltage, and a reset signal is applied to the reset transistor 13. As a result, the output transistor 11 is turned on, and the signal readout circuit is activated. Also in this embodiment, the same effect as that of the fifth embodiment can be obtained.

(Seventh embodiment)
FIG. 9 is a circuit diagram of a signal readout circuit used in the photoelectric conversion film laminated color solid-state imaging device according to the seventh embodiment of the present invention. The element structure is the same as that of each of the above-described embodiments. However, in the photoelectric conversion film stacked color solid-state imaging device to which the present embodiment is applied, the electron-positive generated in the pixel by the photoelectric conversion film (G pixel in the above example). In the hole pair, holes are used as signal charges, and a signal corresponding to the amount of holes is read by the signal reading circuit of the present embodiment.

  The signal readout circuit shown in FIG. 9 has the same basic configuration as the signal readout circuit 50 having the three-transistor configuration shown in FIG. 2, but the terminal 49 connected to the drain of the reset transistor 13 and the drain of the output transistor 11 The difference is that the terminal 48 connected to is a separate terminal.

  In the signal readout circuit having such a configuration, when a color signal corresponding to the hole signal charge amount of the G pixel is read out to the column signal line 27, a high voltage during normal operation is supplied to the terminal 48, and a moderate voltage is supplied to the terminal 49. Supply voltage. When a reset signal is applied to the reset transistor 13, the gate voltage of the output transistor 11 becomes a medium voltage. Therefore, even if positive signal charges (holes) flow into the gate of the output transistor 11 in the G pixel and the gate voltage rises, the source follower circuit of the output transistor 11 operates normally.

  In each of the embodiments described above, the case where the output signal is an analog signal has been described. However, as a matter of course, it may be a digital output signal. In that case, an ADC (analog / digital conversion unit) is provided at the output unit in the output signal processing unit, and analog signals are converted into digital signals at once, or an ADC is provided after the correlated double sampling circuit, and analog for each column. The signal may be converted into a digital signal.

  In each of the above-described embodiments, the microlens is not described, but a microlens may be provided to improve the light collection efficiency of the B pixel and the R pixel provided on the semiconductor substrate. The microlens is provided as a top lens on the insulating film 45 in FIG. 2 or as an inner lens inside the insulating film 41. Thereby, the sensitivity of R pixel and B pixel further improves.

  In each of the above-described embodiments, the R pixel and the B pixel provided on the semiconductor substrate side are provided in the depth direction of the semiconductor substrate. However, the R pixel and the B pixel are alternately arranged in a planar shape on the semiconductor substrate. It is also possible to apply each embodiment mentioned above to the photoelectric conversion film lamination type color solid-state image sensor which laminates the photoelectric conversion film which constitutes G pixel. In this case, the R pixel and the B pixel may be configured by photodiodes in which color filters are stacked.

  Although the embodiment in which the R pixel and the B pixel are configured by photodiodes and the G pixel is configured by a photoelectric conversion film has been described, this is merely an example, and a pixel in which one of the three primary colors is configured by a photoelectric conversion film. In general, the above-described embodiments can be applied to a photoelectric conversion film stacked color solid-state imaging device configured to detect and detect the other two colors with a photodiode.

  As described above, according to the embodiments of the present invention, the R pixel and the B pixel provided on the semiconductor substrate side are read out by the four-transistor signal readout circuit so that the R and B color signals are read out. The G pixel by the photoelectric conversion film can be read out, and the G color signal is read out by the signal readout circuit having a three-transistor configuration, so that the unread read charge (residual charge) that causes the afterimage of the G color can be reduced. It is possible to capture a color image.

  Further, according to each embodiment of the present invention, the number of transistors can be reduced by sharing the signal readout circuit for the B pixel and the R pixel, and the light receiving area of the R pixel and the B pixel can be increased accordingly. , Improve sensitivity and saturation output voltage.

  As a result, an image sensor with a finer pixel size can be manufactured, and a high-resolution image sensor can be realized. Further, by reducing the number of analog circuit units in the output signal processing unit from three to two or one per pixel column, the chip size of the image sensor can be further reduced, and the cost of the image sensor is further reduced. It becomes possible.

  Furthermore, according to the second and third embodiments of the present invention, the reset noise signal and the reset noise one frame before are included with respect to the output signal of the G pixel, in which random noise cannot be removed in principle by the correlated double sampling circuit. Since the image signal is output separately, the random noise of the G pixel signal is greatly reduced by subtracting the reset noise signal from the previous frame and the image signal using a frame memory or the like outside the image sensor. This makes it possible to capture a better color image.

  In the above-described embodiment, the sum signal of 4 pixels in total of 2 pixels in the row direction × 2 pixels in the column direction is obtained, but the present invention is not limited to this. For example, in the correlated double sampling circuit 53 shown in FIG. 3, two sample hold circuits 58 and 59 are provided, but four sample hold circuits are provided, and the SH selection switch 60 is one of the four sample hold circuits. By selecting one of them, it is possible to add four pixels in the column direction.

  Also, pixel addition in various row directions can be performed by changing the combination of row direction scan switches that apply row direction scanning signals simultaneously (or at continuous timing). The number of pixels added in the column direction depends on the number of sample and hold circuits provided in the correlated double sampling circuit 53, but the number of pixels added in the row direction is determined by the number of correlated double sampling circuits 53 that are read simultaneously. If the row direction scanning switches of the three correlated double sampling circuits 53 adjacent to each other in the row direction are simultaneously selected, pixel addition of the three pixels in the row direction is performed. If four circuits 53 are simultaneously selected, four pixels in the row direction are added. Pixel addition is performed.

  As described above, according to each embodiment of the present invention, it is possible to select the all-pixel readout operation and the color signal addition readout operation. Therefore, in the digital camera equipped with the photoelectric conversion film laminated solid-state imaging device according to each of the above embodiments, the color signal addition operation is selected when shooting a still image and a moving image in a dark scene where flash light cannot be used. As a result, high-sensitivity and high-quality (high S / N) image shooting becomes possible, and if all-pixel readout operation is selected when shooting a still image of a sufficiently bright scene, a high-quality and high-resolution still image can be obtained. It becomes possible to shoot.

  The photoelectric conversion film laminated solid-state imaging device according to the present invention is easy to manufacture and can capture a color image with good image quality with high sensitivity. Therefore, the conventional CCD-type solid-state imaging device, CMOS-type solid-state imaging device, etc. Useful instead.

It is a surface schematic diagram of the photoelectric converting film lamination type solid imaging device concerning a 1st embodiment of the present invention. FIG. 2 is a schematic cross-sectional view and a signal readout circuit diagram for one unit pixel of the photoelectric conversion film stacked solid-state imaging device shown in FIG. 1. It is a principal part block diagram of the output signal processing part shown in FIG. It is a principal part block diagram of the photoelectric converting film laminated | stacked solid-state image sensor which concerns on 2nd Embodiment of this invention. It is a surface schematic diagram of the photoelectric conversion film laminated | stacked solid-state image sensor which concerns on 3rd Embodiment of this invention. It is a principal part block diagram of the two output signal processing parts shown in FIG. It is a principal part block diagram of the photoelectric conversion film laminated | stacked solid-state image sensor which concerns on 4th Embodiment of this invention. (A) It is the signal read-out circuit diagram of the pixel provided in the semiconductor substrate of the photoelectric converting film laminated | stacked solid-state image sensor concerning 5th Embodiment of this invention. (B) It is a signal read-out circuit diagram of the pixel provided in the semiconductor substrate of the photoelectric converting film laminated | stacked solid-state image sensor concerning 6th Embodiment of this invention. It is a signal read-out circuit diagram which reads the signal according to the signal charge by the hole detected by the pixel comprised with the photoelectric conversion film of the photoelectric conversion film laminated | stacked solid-state image sensor concerning 7th Embodiment of this invention. 1 is a basic conceptual diagram of a photoelectric conversion film laminated solid-state imaging device. (A) A signal readout circuit diagram of a three-transistor configuration. (B) It is a signal readout circuit diagram of a 4-transistor configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Output transistor 12 Row selection transistor 13 Reset transistor 14, 14R, 14B Read transistor 20, 70 Photoelectric conversion film lamination | stacking type color solid-state image sensor 21 Semiconductor substrate 22 Unit pixel 23rb, 23g, 24 Output signal processing part 25 Column direction scanning control part 26 Column signal line for R pixel / B pixel 27 Column signal line for G pixel 28, 29 Read signal line 30 Reset signal line 31 Row selection signal line 36 n region layer 37 constituting red light detection photodiode 37 Blue light N region layer 43 constituting the detection photodiode 43 green light detection photoelectric conversion film 48, 49 terminal 50 G pixel signal readout circuit 51 R pixel / B pixel signal readout circuit 53 correlated double sampling circuit 54 row direction Scan control unit 55 Output unit 56 Column signal line selection switch circuit 57 Clamp circuit 58, 59 Pull-hold (SH) circuit 60 SH selection switch circuits 62 read the output signal line 67 clamp control switch circuit

Claims (17)

A first color pixel in which a plurality of unit pixels are arranged in a two-dimensional array on the surface portion of the semiconductor substrate, and each unit pixel detects the incident light amounts of the three primary colors, the first color, the second color, and the third color, respectively. , Second color pixels, and third color pixels, and the first color pixels are composed of photoelectric conversion films laminated on the surface of the semiconductor substrate, and each of the second color pixels and the third color pixels. Is a photodiode formed on the surface of the semiconductor substrate, and the detection signals of the first color pixel, the second color pixel, and the third color pixel are provided on the semiconductor substrate for each unit pixel. In the photoelectric conversion film laminated solid-state imaging device read by the circuit,
Signal memory means for each pixel column of the unit pixels and holding each of the signals read from adjacent color pixels of the same unit pixel row, and the signal held in each of the signal memory means An all-pixel reading operation for individually reading out and outputting the signals to the outside, and an addition reading operation for simultaneously reading out the signals of the signal memory means adjacent to each pixel column among the signals held in each of the signal memory means and outputting them to the outside A photoelectric conversion film stacked solid-state imaging device, comprising: an output signal processing unit having a row-direction scanning control unit that performs switching.   The output signal processing section includes a plurality of the signal memory means provided for each of the pixel columns, and is read from the color pixels of the same color adjacent to each of the plurality of signal memory means in the column direction of the unit pixels. 2. The photoelectric conversion film laminated solid-state image pickup device according to claim 1, further comprising a memory unit changeover switch for holding each of the signals.   The output signal processing unit includes a first output signal processing unit for the first color pixel, and a second output for the second color pixel and the third color pixel that operate in parallel with the first output signal processing unit. The photoelectric conversion film laminated solid-state imaging device according to claim 1, wherein the photoelectric conversion film stack-type solid-state imaging device is configured with a signal processing unit.   The signal readout circuit that reads out the detection signal of the first color pixel is a signal readout circuit that includes a reset transistor, a row selection transistor, and an output transistor, and the signal readout circuit that reads out the detection signal of the second color pixel; 4. The signal readout circuit for reading out the detection signal of the third color pixel is a signal readout circuit comprising four transistors, ie, a readout transistor, a reset transistor, a row selection transistor, and an output transistor. The photoelectric conversion film laminated solid-state imaging device according to any one of the above.   Of the transistors constituting the signal readout circuit for reading out the detection signal of the second color pixel, three transistors excluding the readout transistor among the transistors constituting the signal readout circuit of the signal reading circuit for reading out the detection signal of the third color pixel 5. The photoelectric conversion film stacked solid-state imaging device according to claim 4, wherein the photoelectric conversion film stack type solid-state imaging device is configured to be shared with three transistors excluding the readout transistor, and the two readout transistors are turned on and off at different timings.   The output signal processing unit switches between an output signal of a signal reading circuit that reads a detection signal of the first color pixel and an output signal of a signal reading circuit that reads the detection signal of the second color pixel and the third color pixel. The photoelectric conversion film stack type solid-state image pickup device according to claim 2, further comprising a switching unit for taking in the image.   The output signal processing unit includes a circuit for performing a sample hold process on the captured detection signal of the first color pixel, and correlated double sampling with respect to the captured detection signal of the second color pixel and the third color pixel. A photoelectric conversion film stacked solid-state imaging device according to claim 4, further comprising a circuit that performs processing.   The correlated double sample processing is performed by a clamp circuit that clamps an input signal and a sample hold circuit that samples and holds the output of the clamp circuit, and the sample hold processing bypasses the clamp circuit by a bypass circuit, The photoelectric conversion film laminated solid-state imaging device according to claim 7, wherein the photoelectric conversion film stacking type solid-state imaging device is performed.   After the detection signal of the first color pixel is read from the signal readout circuit to the output signal processing unit, the reset noise signal is output from the signal readout circuit before the detection signal of the next first color pixel is read out. 9. The photoelectric conversion film stacked solid-state imaging device according to claim 7 or 8, wherein the readout is performed by a signal processing unit.   6. The configuration according to claim 4, wherein a row selection transistor is omitted from the signal readout circuit having the four-transistor configuration, and a voltage applied to a drain terminal of the reset transistor is variably controlled instead. The photoelectric conversion film laminated solid-state imaging device described.   11. The photoelectric conversion according to claim 1, wherein the photoelectric conversion film has a single layer organic semiconductor structure or a multilayer organic semiconductor structure sandwiched between a transparent pixel electrode film and a counter electrode film. Film stack type solid-state imaging device.   12. The photodiode according to claim 1, wherein the photodiode constituting the second color pixel and the photodiode constituting the third color pixel are provided apart from each other in a depth direction of the semiconductor substrate. The photoelectric conversion film laminated solid-state imaging device according to any one of the above.   13. The photoelectric conversion film stacked solid-state imaging according to claim 1, wherein each of the first color pixel, the second color pixel, and the third color pixel detects an incident light amount as an electron amount. element.   13. The method according to claim 1, wherein the first color pixel detects an incident light amount by a hole amount, and the second color pixel and the third color pixel detect an incident light amount by an electron amount. A photoelectric conversion film laminated solid-state imaging device according to claim 1.   15. The photoelectric conversion film stacked solid-state imaging device according to claim 1, wherein an output signal of the output signal processing unit is an analog signal.   16. The photoelectric conversion film stacked solid-state imaging device according to claim 1, wherein an output signal of the output signal processing unit is a digital signal.   The photoelectric conversion film stacked solid according to any one of claims 1 to 16, wherein the first color is green, the second color is blue, and the third color is red. Image sensor.

Images