JP2011166394A - Imaging device, imaging method and image input device - Google Patents

Abstract

Noise reduced in a signal transmission system is reduced.
PD1 generates electrons and holes in pairs by the incidence of electromagnetic waves. Two amplifier circuits of four NMOS (4-7) and four PMOS (11-14) amplify electrons and holes separately. The electronic signal line 8 and the hole signal line 15 are arranged as a pair of transmission lines for separately transmitting the electronic signal and the hole signal from the two amplifier circuits. The synthesizing circuit 18 inputs an electronic signal from the electronic signal line 8 and a hole signal from the hole signal line 15, and synthesizes common mode noise on the transmission line by obtaining a synthesized signal equivalent to the difference in signal potential. Exclude from signal.
[Selection] Figure 1

Description

  The present invention relates to an imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) sensor that individually transmits electrons and holes generated by photoelectric conversion within the device and outputs them after processing. The present invention also relates to an imaging method including internal transmission and processing techniques. Furthermore, the present invention relates to an image input apparatus that includes the imaging device in an image input unit.

  In general, solid-state imaging devices generate electrons and holes in pairs in photodiodes that convert incident light into electrical signals, but currently only electrons are taken out as imaging signals and no hole signals are used. .

  Techniques have been reported in which the amplitude of a signal is doubled compared to the prior art by extracting and amplifying the signals of electrons and holes from one photodiode (see Patent Documents 1 and 2).

Japanese Patent Application No. 10-234088 JP 2008-147486 A

An imaging device is usually used by a camera or the like to convert the magnitude of electromagnetic waves (usually invisible light such as visible light or infrared light) into an electrical signal. Usually, the imaging device is placed near a focus device that moves a lens or the like using a motor. In this case, for example, a magnetic field generated from the focus device may jump into a closed circuit that forms the imaging device and generate noise due to induced electromotive force.
Further, when the voltage is reduced due to miniaturization, noise caused by electromagnetic waves generated from the imaging device circuit becomes a disturbance factor of the imaging signal.

In Patent Documents 1 and 2, the resolution can be increased by doubling the pixel signal, but reduction of noise entering from the outside is not considered at this time.
Further, the effect of doubling the signal can be obtained only by taking out the electron and hole signals from one photodiode.
In addition, the photodiode structure disclosed in the patent document does not have a HAD structure that cares for hole signals. In the HAD structure, the electron dark current generated in the photodiode surface region is reduced in the hole accumulation region formed on the surface of the photodiode. When holes are accumulated in the surface area of the photodiode to reduce the electron dark current, there is an advantage that the pixel signal is doubled. However, as a disadvantage, a false color is generated.

  The present invention provides an imaging device that reduces noise mixed in a signal transmission system and an operation method thereof. The present invention also provides an image input apparatus having such an imaging device.

An imaging device according to the present invention includes a photoelectric conversion element, two amplifier circuits, two signal lines, and a synthesis circuit.
The photoelectric conversion element generates electrons and holes in pairs by incidence of electromagnetic waves.
The two amplifier circuits amplify electrons and holes separately.
The two signal lines are arranged as a pair of transmission lines for separately transmitting an electronic signal and a hole signal from the two amplifier circuits.
The synthesizing circuit inputs an electronic signal and a hole signal from the two signal lines, and obtains a synthesized signal equivalent to the difference in signal potential, thereby eliminating common mode noise on the transmission line from the synthesized signal.

  The imaging method according to the present invention photoelectrically converts a radiated electromagnetic wave to generate electrons and holes in pairs, amplifies the generated electrons and holes separately, and separates the electron signal and hole signal obtained by the amplification separately. The signal is transmitted through two signal lines arranged as a pair of transmission lines that are transmitted to each other, and one of the post-transmission electron signal and hole signal is inverted and synthesized to synthesize the common mode noise on the transmission line. Exclude from signal.

  An image input apparatus according to the present invention includes an imaging device having the above-described configuration and the present invention applied to an image input unit together with an optical system.

According to the above configuration, the electronic signal and the hole signal generated in the photoelectric conversion element have substantially the same amplitude although their polarities are opposite. In view of this, in the present invention, a transmission line (two pairs of signal lines) is formed by pairing an electronic signal and a hole signal. As a result, the closed circuit in which the electronic signal flows and the closed circuit in which the hole signal flows have substantially the same area. For this reason, noise (common mode noise) equally enters the pair of transmission lines (two signal lines).
The electronic signal and hole signal after transmission are synthesized by inverting one of the signals in a synthesis circuit. As a result, noise (common mode noise) that equally enters the electronic signal line and the hole signal line is almost completely canceled.

  According to the present invention, it is possible to provide an imaging device, an imaging method, and an image input apparatus capable of canceling common mode noise that enters a signal transmission path by an external electromagnetic field or the like.

It is a block diagram including the pixel circuit of the imaging device concerning 1st Embodiment which takes out a hole and an electron from one PD. FIG. 2 is a schematic plan view of a pixel circuit configured as shown in FIG. 1. It is a conceptual diagram of the signal which propagates the signal line for electrons and the signal line for holes. It is a conceptual diagram of the signal synthesize | combined from the signal which propagates the signal line for electrons and the signal line for holes. It is PD schematic sectional drawing which has a transparent electrode in the case of taking out a hole and an electron. It is PD schematic sectional drawing which has a negative charge insulating film in the case of taking out a hole and an electron. It is a circuit diagram in the case where a fixed potential wiring (or floating potential wiring) is added to an electronic signal line and a hole signal line. It is a block diagram including the pixel circuit of the imaging device concerning 2nd Embodiment which takes out a hole and an electron from two PD for electrons and holes. FIG. 9 is a schematic plan view of the pixel circuit having the configuration shown in FIG. 8. It is a schematic sectional drawing of PD for taking out the electron which can be used in 2nd Embodiment. It is a schematic sectional drawing of PD for taking out the hole which can be used in 2nd Embodiment. It is a structural diagram of an imaging device having an organic photoelectric conversion film structure as a photoelectric conversion element. It is another structural drawing of the imaging device which has an organic photoelectric conversion film structure as a photoelectric conversion element. It is a conceptual block diagram of the image input device (for example, camera) using the imaging device concerning 4th Embodiment.

Embodiments of the present invention will be described in the following order with reference to the drawings, taking as an example the case where the present invention is applied to a CMOS sensor.
1. First embodiment: a single PD.
2. Second embodiment: two PDs.
3. Third Embodiment: Organic photoelectric conversion film.
4). Fourth Embodiment: Image input device.

<1. First Embodiment>
FIG. 1 is a configuration diagram including a pixel circuit of a CMOS sensor according to the first embodiment.

  A pixel circuit PIX shown in FIG. 1 includes a photodiode (PD) 1 as a “photoelectric conversion element” that photoelectrically converts input light, four NMOS transistors (4 to 7), and four PMOS transistors (11 to 14). ).

The cathode of PD1 is connected to the source of the transfer transistor 4. The drain of the transfer transistor 4 is connected to the floating diffusion portion.
A reset transistor 7 is connected between the node ND and the supply line of the power supply voltage Vdd. The gate of the reset transistor 7 is connected to the electronic reset line 10. The reset transistor 7 switches the node ND from a floating state to a connection state to the supply line 15 of the power supply voltage Vdd that is a supply line of the power supply voltage Vdd, and charges the node ND with the power supply voltage Vdd.

An amplification transistor 5 and a selection transistor 6 are connected in series between the supply line of the power supply voltage Vdd and the electronic signal line 8.
The gate of the amplification transistor 5 is connected to the node ND, and the gate of the selection transistor 6 is connected to the electron vertical selection line 9. Similar to the electronic reset line 10, the electronic vertical selection line 9 is a wiring common to pixels in the same row.
The transfer transistor 4 transfers the charge accumulated in the photodiode PD (electrons in this circuit portion) to the node ND that is again in a floating state after reset. The amplifying transistor 5 amplifies a pixel signal corresponding to the accumulated charge transferred to the node ND. The selection transistor 6 controls the output of the output of the amplification transistor 5 to the electronic signal line 8.

  The circuit portion described above is a portion relating to extraction of electrons, and an electronic signal is amplified by the amplification transistor 5 through the transfer transistor 4 from the photodiode 1 in which electrons and holes are generated in pairs, and the electronic signal line is transmitted through the selection transistor 6. 8 is output.

The remaining four PMOS transistors (11 to 14) of the pixel circuit PIX are connected to the anode side of the photodiode 1 and constitute a circuit portion for extracting holes.
Specifically, a transfer transistor 11 having a function similar to that of the transfer transistor 4 (however, the charge polarity to be handled is reversed and the same applies hereinafter) is provided. A reset transistor 14 having the same function as the reset transistor 7 is provided. The reset transistor 14 is connected to a hole reset line 17 wired in the row direction as a pair with the electron vertical selection line 9. Similarly, an amplification transistor 12 corresponding to the amplification transistor 5 and a selection transistor 13 corresponding to the selection transistor 6 are provided. The reset potential is a supply line potential (eg, 0 [V]) of the reference voltage Vss, and the bias potentials of the amplification transistor 12 and the selection transistor 13 are also 0 [V], for example.
The drain of the selection transistor 13 is connected to the hole signal line 15.

  In the hole extraction circuit described above, holes generated in the photodiode 1 are amplified by the amplification transistor 12 through the transfer transistor 11 and sent to the hole signal line 15 through the selection transistor 13. The electric charge that is no longer needed is released by operating the reset transistor 7 or 14.

  The electronic signal line 8 and the hole signal line 15 are arranged and wired near each other as a pair of transmission lines. As a result, external noise such as a magnetic field enters the electron signal line 8 and the hole signal line 15 equally. Whether the potential is fixed at a fixed potential between the electron signal line 8 and the hole signal line 15 in order to reduce crosstalk of the signal line due to the electric field generated between the electron signal line 8 and the hole signal line 15; An electrically floating wiring may be arranged.

FIG. 2 is a pattern diagram of the circuit diagram of FIG. 1 viewed from above.
Near the center of the large N-well, a light-receiving portion of the photodiode 1 is formed, and for example, a P-well (denoted as “1PD”) in which the hole accumulation layer on the surface of the HAD structure is a resurface layer is formed. Further, a small P well (denoted as “4TrN”) for forming the drain D (4) of the transfer transistor 4 and a vertically long for forming the amplification transistor 5 and the selection transistor 6 at one corner of the rectangle. A P-well is formed.

The drain D (4) of the transfer transistor 4 is formed in the P well (4TrN) and overlaps with the corner of the gate G (4) in plan view. The transfer transistor 4 uses this corner as a current channel.
The gate G (11) of the transfer transistor 11 is arranged at another corner of the large P well serving as the source (4), and the source S (11) of the transfer transistor 11 is located inside the P well inside the N well outside the corner. The drain D (11) of the transfer transistor 11 is formed.

  The drain D (4) is connected to the gate G (5) of the amplification transistor 5 through a wiring of a node ND (not shown) (not shown). The gate G (5) is arranged in a vertically long P-well, the n-type region on one side in the width direction is biased to the power supply voltage Vdd, and the source / drain region (S / D) on the other side is shared with the selection transistor 6 Has been. Another impurity region adjacent to the gate G (6) of the selection transistor 6 is connected to the electronic signal line 8 via a contact (not shown).

  The drain D (11) is connected to the gate G (12) of the amplification transistor 12 by a wiring of a node ND (not shown) (not shown). The gate G (12) is disposed in the N well, the n-type region on one side in the width direction is biased to the reference voltage Vss, and the source / drain region (S / D) on the other side is shared with the selection transistor 13. Yes. Another impurity region adjacent to the gate G (13) of the selection transistor 13 is connected to the hole signal line 15 via a contact (not shown).

The electronic signal line 8 and the hole signal line 15 are parallel to each other as a pair transmission line in the plan view here.
As described above, in FIG. 2, the electron signal lines 8 and the hole signal lines 15 are paired side by side in a plane parallel to the semiconductor substrate surface, but may be a stacked pair wiring parallel to the direction perpendicular to the semiconductor substrate surface. .

FIG. 3 shows a waveform diagram in which flying noise (or induction noise) is superimposed as an electromagnetic wave from the outside on the electronic signal and hole signal to which signals are sent in pairs. 3A shows the electronic signal of the electronic signal line 8, and FIG. 3B shows the hole signal of the hole signal line 15.
The electronic signal and the hole signal are transferred as signals whose phases are reversed (180 ° inversion). On the other hand, the arrangement of the electronic signal line 8 and the hole signal line 15 as a pair transmission line means that common mode noise having the same phase and the same amplitude is superimposed on the two signals in the same manner.

  As shown in FIG. 1, a synthesis circuit (strictly, a differential output circuit) 18 is provided at the other end of the pair transmission line of the electronic signal line 8 and the hole signal line 15. This circuit is desirably provided in the processing circuit path from the first stage to the input of the ADC (AD converter) when the imaging device has a processing circuit for each column.

  FIG. 4 shows a waveform diagram of the synthesized signal at the output of the synthesis circuit 18. This waveform is equivalent to a signal obtained by subtracting the hole signal of the hole signal line 15 from the electron signal of the electronic signal line 8 in the phase relationship with FIG. Thereby, thereafter, the combined signal is handled in the same way as the conventional pixel signal, and other processing is executed.

  Note that the synthesis of the electronic signal and the hole signal may be performed after AD conversion of the signal. When signals are combined after AD conversion, the combining circuit may be an adding circuit instead of a difference circuit depending on the specifications of the comparator.

FIG. 5 is a cross-sectional structure diagram of the PD 1 in the configuration of FIGS.
A P well 20 having a planar pattern shown in FIG. 2 is formed on a semiconductor substrate (not shown), and an N-type region 19 which is a main storage layer of electrons as signal charges is formed in the P well 20. Yes.
Transparent electrodes 22 are stacked on the surfaces of the N-type region 19 and the P well 20 with an insulator 21 interposed therebetween. The transparent electrode 22 is made of a transparent electrode material such as ITO or IZO, and is usually provided as an electrode common in potential to all pixels.

  In the present embodiment, although not essential, as a preferred configuration, a negative potential is applied to the transparent electrode 22 to form the hole accumulation layer 23 on the surface of the photodiode.

Alternatively, as another preferred configuration, an insulating film having a negative fixed charge (hereinafter referred to as negative charge insulating film 24) is deposited on the photodiode as shown in FIG. The negative charge insulating film 24 is formed by depositing an insulating material (HfOx or the like) containing at least one element among, for example, hafnium, zirconium, aluminum, tantalum, titanium, yttrium, and lanthanoid elements. Accordingly, the hole accumulation layer 23 is formed on the surface of the photodiode, thereby minimizing the hole buffer region and suppressing the generation of false color.
For the purpose of obtaining the same effect, when the impurity conductivity type of the photodiode is opposite to the above, an insulating film having a positive fixed charge may be deposited on the photodiode.
The negative charge insulating film 24 or the positive charge insulating film shown in FIG. 6 is preferably a film made of a material having a relative dielectric constant of 5 or more.

  Further, as shown in FIG. 7, by arranging a fixed potential wiring VL <b> 1 whose potential is fixed at a fixed potential such as ground between the electronic signal line 8 and the hole signal line 15, the electronic signal line 8 and the hole signal line are arranged. Crosstalk between 15 signals can be suppressed.

  Further, in place of the fixed potential wiring VL1 of FIG. 7, by arranging the floating potential wiring VL2 in which the potential is floated between the electron signal line 8 and the hole signal line 15, the electronic signal line 8 and the hole signal line are arranged. Crosstalk between 15 signals can be suppressed.

  5-7 is a preferable modification of the structure shown in FIG. 1 and FIG. 2 prior to that, any one of the structures or any combination thereof may be used. When both VL1 and the floating potential wiring VL2 shown in FIG. 7 are used, the floating potential wiring VL2 can be disposed between the signal lines, and two fixed potential wirings VL1 can be disposed on both outer sides to be shielded. Although the noise superimposition itself can be suppressed by using a shield, the effect of the present invention can be sufficiently expected because such a simple wiring shield is not sufficient.

  According to the present embodiment, it is possible to cancel common mode noise that enters the signal transmission path due to an external electromagnetic field or the like. In particular, in this embodiment, since an electronic signal and a hole signal are taken out from one photoelectric conversion element, the amplitude of a signal that can be obtained is doubled. Therefore, ideally, the S / N ratio is √2.

<2. Second Embodiment>
FIG. 8 is a configuration diagram including a pixel circuit showing an example of the configuration of the present invention.
Comparing FIG. 8 with FIG. 1, FIG. 8 includes PD2 (first photoelectric conversion element) for extracting electrons and PD3 (second photoelectric conversion element) for extracting holes. The configuration of the other transistor circuit section itself is substantially the same in FIGS.

  Light incident on the electron PD 2 generates electrons and holes in pairs. The electrons are amplified by the amplification transistor 5 through the transfer transistor 4 and transferred to the electronic signal line 8 through the selection transistor 6. Since the signal is extracted from the electron and hole signals, the area of the PD2 for electrons may be half the area of the conventional photodiode.

  Similarly, holes generated in the hole PD 3 are amplified by the amplification transistor 12 through the transfer transistor 11, and sent to the hole signal line 15 through the selection transistor 13. The unnecessary charge is released by operating the reset transistor 14 (7 in the case of electrons). Since the signal is extracted from the electron and hole signals, the area of the hole photodiode may be half the area of the conventional photodiode.

FIG. 9 is a plan view of the pixel circuit PIX having the configuration shown in FIG. FIG. 9 shows the electron signal line 8 and the hole signal line 15 arranged in a plan view. As described in the explanation of FIG. 2, two signals are passed through the insulating layer in the direction perpendicular to the semiconductor substrate. You may wire by overlapping a line.
The lower half of FIG. 9 is an electron extraction pixel portion, and the upper half is a hole extraction pixel portion.
The two pixel portions differ only in the P-type and N-type impurity conductivity types, and have line-symmetric figures as circuit patterns. Thus, for electronic use, the drain D (4) of FIG. 2, that is, the drain region of the transfer transistor 4 is arranged in the approximate center of the circuit portion. The drain D (4) is shared by the four color pixels. Since the potential here is a fixed potential, such a shared structure is possible. Normally, a pixel assigned with one color is called a pixel, a pixel unit of a basic unit of color arrangement (RGB, RGBG, RGBW, etc.) is called a pixel, and one unit is called a sub-pixel. There is. Here, it is called a color pixel.

Here, an RGBG Bayer array is illustrated. However, it is an arrangement when the electron and hole are viewed independently, and actually, the electron red pixel photodiode and the hole red pixel photodiode are arranged adjacent to each other. The same applies to other colors. Note that the transistor circuit on the output side is shown only for two circuits for electrons and holes, but transistor circuits for other color pixels are also provided.
The basic inter-pattern connection relationship is basically the same as that shown in FIG. 2 and will not be described here. The red pixel for electrons and the red pixel for holes correspond to one original red pixel.

As described above, in the present embodiment, the potential-fixed impurity region is shared by the four color pixels in the electron and hole pixel arrangement regions, and the electron color pixel and the hole color for the same color are used. The output from the color pixel is transmitted in pairs.
By arranging the electronic signal line 8 and the hole signal line 15 in the vicinity of each other, noise from the outside such as a magnetic field is equally input. In order to alleviate signal line crosstalk caused by the electric field generated between the electron signal line 8 and the hole signal line 15, the potential is fixed between the electron signal line 8 and the hole signal line 15 at a fixed potential such as ground. Wiring, electrically floating wiring, or a combination of both may be arranged.

  A difference circuit (synthesizing circuit 18: FIG. 8) takes a difference between the electronic signal and the hole signal sent as a pair and a difference in signal amplitude. As a result, the combined signal can be processed by performing the same processing as the conventional pixel signal as the final pixel signal. When the areas of the photodiodes are the same, the combined signal intensity is not doubled as in the first embodiment, but a signal intensity comparable to the conventional one can be obtained.

  As shown in FIG. 10, the electron PD2 has a structure in which a hole accumulation layer 27, which is a P-type semiconductor region having a high impurity concentration, is shallowly formed on an N-type region 26 in a P-well 25. Is desirable. Further, a structure as shown in FIGS. 5 and 6 can also be employed.

  As shown in FIG. 11, the hole photodiode has a structure in which an N-type region 28 is formed in a P-well 25, a P-type region 29 is formed in the N-type region 28, and an N-type impurity having a high impurity concentration. The electron storage region 30 which is a type semiconductor region is preferably formed shallow. Further, a structure in which the impurity conductivity type is reversed in the configurations of FIGS. 5 and 6 is also possible.

<3. Third Embodiment>
The present embodiment relates to an imaging device that generates electrons and holes from incident light using an organic photoelectric conversion film instead of a photodiode.

FIG. 12 shows a laminated film structure of the photoelectric conversion portion.
When the organic photoelectric conversion film structure illustrated in FIG. 12 is used, voltage is applied to the transparent electrodes 33, 36, 37, 39, 41, 43 sandwiching the organic photoelectric conversion films 34, 38, 42 (quinazoline derivatives, quinacridone derivatives, etc.). Apply.
Alternatively, as illustrated in FIG. 13, electrons and holes are separated by introducing organic n-type semiconductors 44, 46, 48 and organic p-type semiconductors 45, 47, 49 into the organic photoelectric conversion films 34, 38, 42. Remove from the electrode. The extracted electrons and holes are transferred from the transfer transistor to the amplification transistor and amplified, and then the electron signal and hole signal are transferred through the pair transmission line (electron signal line 8 and hole signal line 15). Thereafter, as in the other embodiments described above, the amplitude of one signal can be inverted and then combined. The positional relationship between the organic n-type semiconductor and the organic p-type semiconductor may be switched.
Also in this embodiment, in order to alleviate the signal line crosstalk caused by the electric field generated between the electron signal line 8 and the hole signal line 15, the potential is grounded between the electron signal line 8 and the hole signal line 15. A wiring fixed at a fixed potential, a wiring that is electrically floating, or a combination of both may be arranged (see FIG. 7 and the like).

<4. Fourth Embodiment>
FIG. 14 relates to an image input apparatus 100 (here, a camera is illustrated) that employs an imaging device like the present invention. As shown in FIG. 14, the image sensor 101 (a part of an image input unit (not shown)), an image signal processing unit 102, a camera control unit 103, an image signal recording unit 104, and an image signal output unit 105 are included.
Here, an optical system is disposed in the vicinity of the image sensor 101, and the image sensor 101 is disposed so that an imaging surface of the optical system is a light receiving surface. As the imaging device 101, the ones related to the first to third embodiments and the modifications thereof are used.
Therefore, it is possible to record an image with less noise and less affected by an external electromagnetic field. Therefore, according to the present embodiment, a low noise camera system using an imaging device such as a CMOS sensor is realized.

In devising the present invention, the inventor transmits a signal using a signal transmission line including a signal transmission line, a signal transmission line obtained by inverting the signal, and a ground line during signal transmission. We studied to cancel the common mode noise that enters during the transmission process.
If the above method is used in the signal transmission process of the imaging device, the noise generated by the external electromagnetic wave can be eliminated, but if an apparatus for generating a signal and an inverted signal is added to each pixel, the imaging device There is a problem that it becomes too large to fit in the camera.

  The present invention includes a configuration in which the area per pixel is slightly larger than the conventional one. However, the present invention is particularly effective when it is desired to obtain a noise canceling effect, and image signal transmission can be performed with a reasonable imaging device size. System noise can be canceled.

  On the other hand, when taking out the signal of an electron and a hole from one photodiode, it is necessary to care about the dark current by the electron and the hole which generate | occur | produce on the surface of a photodiode.

  In a normal imaging device, only electrons are used as signals. Therefore, a P + impurity region (HAD region) is formed thick (about 0.1 μm) so that the surface of the photodiode becomes rich in holes. When this HAD region is present, the generated holes flow here and become a buffer for accumulating holes, so that it is difficult to extract all hole signals. However, since the photodiode surface is rich in holes, it is presumed that dark current due to generation of holes in the photodiode surface region is suppressed in a thermal equilibrium state.

  In the embodiment of the present invention, instead of a thick HAD structure, an extremely thin hole accumulation state is deposited on the surface of the photodiode by an electric field generated by a transparent electrode, or an insulating film having a fixed charge is deposited on the photodiode. This forms an extremely thin hole accumulation state, suppresses generation of electrons and holes in the photodiode surface region, and minimizes the region as a hole or electron buffer layer. As a result, it is possible to extract an electronic signal and a hole signal with a small dark current and a small false color from a single photodiode. This is effective not only for false color suppression but also noise suppression.

  In the embodiment of the present invention, by using these techniques, it is possible to reduce noise mixed in a signal transmission system of an imaging device such as a CMOS sensor. Further, even if noise suppression processing (synthesis processing) is performed or color processing is performed using the combined signal, an image with no false color or a sufficiently suppressed false color can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... PD, 2 ... Electron PD, 3 ... Hole PD, 4 ... Transfer transistor, 5 ... Amplification transistor, 6 ... Selection transistor, 7 ... Reset transistor, 8 ... Electron signal line, 9 ... Electron vertical selection Lines 10, electronic reset lines 11, transfer transistors, 12 amplification transistors, 13 selection transistors, 14 reset transistors, 15 hole signal lines, 18 synthesis circuits, 20 P-wells, 21 insulators, 22 ... Transparent electrode, 23 ... Hole accumulation layer, 24 ... Negative charge insulating film, 25 ... P well, 26 ... PD for electrons, 27 ... Hole accumulation layer, 28 ... N-type region, 29 ... P-type region, 30 ... an electronic storage area, 100 ... an image input device.

Claims (16)

A photoelectric conversion element that generates a pair of electrons and holes by incidence of electromagnetic waves;
Two amplifier circuits for amplifying electrons and holes separately;
Two signal lines arranged as a pair of transmission lines for separately transmitting an electronic signal and a hole signal from the two amplifier circuits;
A synthesis circuit that inputs an electronic signal and a hole signal from the two signal lines and obtains a synthesized signal equivalent to the difference between the signal potentials to eliminate common mode noise on the transmission line from the synthesized signal;
An imaging device. The imaging device according to claim 1, wherein a wiring that holds a constant potential is disposed between the two signal lines. The imaging device according to claim 1, wherein a wiring having a floating potential is disposed between the two signal lines. The imaging device according to claim 1, wherein electrons and holes are taken out from one photoelectric conversion element and are separately amplified by the two amplifier circuits. A first photoelectric conversion element for extracting electrons and a second photoelectric conversion element for extracting holes, and an electronic signal extracted from the first photoelectric conversion element is input to one of the two amplifier circuits; The imaging device according to claim 1, wherein the hole signal extracted from the second photoelectric conversion element is input to the other amplifier circuit. A transparent electrode that is formed on the photoelectric conversion element and guides incident light to the photoelectric conversion element;
The imaging device according to claim 1, wherein a voltage is applied to the transparent electrode to form an extremely thin accumulation layer on the surface of the photoelectric conversion element. Including an insulating film having a negative or positive fixed charge inside a waveguide formed on the photoelectric conversion element and guiding incident light to the photoelectric conversion element,
The imaging device according to claim 1, wherein an extremely thin accumulation layer is formed on a surface of the photoelectric conversion element by the fixed charge. The imaging device according to claim 7, wherein the insulating film is made of an insulating material containing at least one element selected from hafnium, zirconium, aluminum, tantalum, titanium, yttrium, and a lanthanoid element. The imaging device according to claim 1, wherein the photoelectric conversion element is a photodiode that generates electrons and holes by incidence of electromagnetic waves. The imaging device according to claim 1, wherein the photoelectric conversion element includes an organic photoelectric conversion film that generates electrons and holes by incidence of electromagnetic waves. Incident electromagnetic waves are photoelectrically converted to generate electrons and holes in pairs,
Amplifies the generated electrons and holes separately,
Transmit through two signal lines arranged as a pair of transmission lines that separately transmit the electronic signal and hole signal obtained by amplification,
An imaging method that eliminates common mode noise on a transmission line from a synthesized signal by inverting one of the electronic signal and hole signal after transmission and synthesizing both. The imaging method according to claim 11, wherein a wiring that holds a constant potential is arranged between the two signal lines to suppress mutual interference of signals. The imaging method according to claim 11, wherein a wiring that holds a floating potential is arranged between the two signal lines to suppress mutual interference of signals. The imaging method according to any one of claims 11 to 13, wherein electrons and holes are extracted from one photoelectric conversion element and are separately amplified. The imaging method according to claim 11, wherein electrons output from a photoelectric conversion element for extracting electrons and holes output from another photoelectric conversion element for extracting holes are separately amplified. An image input unit including a photoelectric conversion element and an optical system for guiding electromagnetic waves to the photoelectric conversion element,
The photoelectric conversion element is
A photoelectric conversion element that generates a pair of electrons and holes by incidence of electromagnetic waves;
Two amplifier circuits for amplifying electrons and holes separately;
Two signal lines arranged as a pair of transmission lines for separately transmitting an electronic signal and a hole signal from the two amplifier circuits;
A synthesis circuit that inputs an electronic signal and a hole signal from the two signal lines and obtains a synthesized signal equivalent to the difference between the signal potentials to eliminate common mode noise on the transmission line from the synthesized signal;
An image input device.

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