JP2016154330A - Photoelectric conversion element, image reading device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element, image reading device, and image forming apparatus that can reduce color shift of a read image.SOLUTION: A photoelectric conversion element according to an embodiment comprises: a photoelectric conversion part that has a plurality of light receiving element rows provided for each of colors to be received, the light receiving element row having a plurality of light receiving elements, arranged in one direction, accumulating electric charge by exposure; and a circuit part that includes a plurality of charge voltage conversion circuits that are formed in an areas different from an area occupied by the photoelectric conversion part and convert the electric charges accumulated by the plurality of light receiving elements respectively into voltage.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a photoelectric conversion element, an image reading apparatus, and an image forming apparatus.

  A color scanner reads an image by scanning a document, but there is a problem that a color shift (hue shift with respect to the original color) occurs depending on vibration during scanning, behavior during document transport, and the like. This is because the color linear sensor reads an image with different pixels for each color. That is, the same document position is read by different pixels, and the reading timing is different for each color.

  For example, Japanese Patent Application Laid-Open No. H10-260260 discloses a photosensitive pixel column of an image sensor in which a plurality of photosensitive pixel columns arranged in the main scanning direction are arranged adjacent to each other in the sub scanning direction and a horizontal transfer register is provided outside the photosensitive pixel column. An image sensor is disclosed in which storage means for saving signal charges for each pixel is disposed between the horizontal transfer register and the horizontal transfer register.

  However, the technique disclosed in Patent Document 1 is a technique peculiar to CCD and has a problem that it cannot be applied to a CMOS linear sensor.

  The present invention has been made in view of the above, and an object thereof is to provide a photoelectric conversion element, an image reading apparatus, and an image forming apparatus that can reduce color misregistration of a read image.

  In order to solve the above-described problems and achieve the object, the present invention is provided with a plurality of light receiving element arrays in which a plurality of light receiving elements that accumulate charges by exposure are arranged in one direction for each color to receive light. A photoelectric conversion unit, and a circuit unit including a plurality of charge-voltage conversion circuits that are formed in a region different from a region occupied by the photoelectric conversion unit and each convert charges accumulated in the plurality of light receiving elements into voltages. Have.

  According to the present invention, it is possible to reduce the color misregistration of a read image.

FIG. 1 is a diagram illustrating the overall configuration of the photoelectric conversion element. FIG. 2 is a diagram illustrating a configuration of a pixel, a pixel circuit, and a storage portion included in the photoelectric conversion element. FIG. 3 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element. FIG. 4 is a diagram illustrating the influence of color misregistration on the entire document. FIG. 5 is a diagram showing the effect of color misregistration on the upper part of black characters written on a document. FIG. 6 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element according to the first embodiment. FIG. 7 is a diagram showing the effect of reducing the color misregistration of the entire document by the configuration shown in FIG. FIG. 8 is a diagram showing the effect of reducing color misregistration in the upper part of black characters written on a document. FIG. 9 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element according to the second embodiment. FIG. 10 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element according to the third embodiment. FIG. 11 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element according to the fourth embodiment. FIG. 12 is a diagram showing the effect of reducing the color misregistration of the entire document by the configuration shown in FIG. FIG. 13 is a diagram showing the effect of reducing color misregistration in the upper part of black characters written on a document. FIG. 14 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in the photoelectric conversion element according to the fifth embodiment. FIG. 15 is a diagram schematically illustrating a configuration of a photoelectric conversion region included in a modification of the photoelectric conversion element according to the fifth embodiment. FIG. 16 is a diagram illustrating an outline of an image forming apparatus including an image reading apparatus having a photoelectric conversion element.

  First, the background that led to the present invention will be described. Conventionally, a CCD is often used as a photoelectric conversion element for a scanner, but in recent years, a CMOS linear sensor has attracted attention due to a demand for high speed. A CMOS linear sensor is the same as a CCD in that incident light is photoelectrically converted by a photodiode (PD), but differs in that charge-voltage conversion is performed near a pixel and output to a subsequent stage.

  FIG. 1 is a diagram illustrating the overall configuration of a CMOS color linear image sensor (photoelectric conversion element) 10. The photoelectric conversion region 20 is provided with approximately 7000 PDs (photodiodes: light receiving elements) for each of RGB colors. The PDs are arranged in one direction for each color of light to be received, and generate charges according to the amount of received light. Each PD is provided with a pixel circuit. That is, the photoelectric conversion area 20 is also provided with about 7000 pixel circuits for each of RGB colors.

  Each pixel circuit converts the charge accumulated in the PD into a voltage signal, and outputs a signal to the analog memory through the readout line. The pixel circuit includes a transfer transistor that transfers the charge of the PD to the floating diffusion (FD), a reset transistor that resets the FD, and a source follower transistor that buffers the FD voltage and outputs it to the readout line. Unlike an area sensor, a linear sensor reads signals independently from RGB pixels, and therefore there is a readout line independently for each pixel.

  The AMEM 26 has, for example, about 7000 analog memories (Cs, which will be described later) for each RGB color, holds a signal for each pixel, and performs image processing on a column basis with three RGB pixels as one pixel group. Output signals sequentially. When the AMEM 26 holds the signal, a global shutter system is realized in which the operation timing of the PD and the pixel circuit, that is, the exposure timing is simultaneous with RGB. Note that the photoelectric conversion element 10 illustrated in FIG. 1 includes a column in which three pixels of RGB are included as one pixel group. However, the column may be formed by a plurality of pixels forming one pixel group. It is not limited to 3 pixels.

  The ADC 27 has the same number of AD converters as the number of columns, and sequentially AD-converts image signals in units of columns. The ADC 27 has the same number of AD converters as the number of columns and performs parallel processing, thereby realizing high-speed operation as a photoelectric conversion element while suppressing the operation speed of the AD converter.

  The signal AD-converted by the ADC 27 is held for each pixel by the parallel-serial converter (P / S) 28, and the held signal is sequentially output to the LVDS 29. The LVDS 29 converts the signal output from the P / S 28 into a low-voltage differential serial signal and outputs it to the subsequent stage. The photoelectric conversion element 10 processes parallel data processed in parallel for each pixel in the main scanning direction on the upstream side of the P / S 28, but processes serial data for each RGB color on the downstream side of the P / S 28. . The timing control unit (TG) 30 controls each unit constituting the photoelectric conversion element 10.

  FIG. 2 is a diagram illustrating a configuration of the pixel 200, the pixel circuit (PIX_BLK) 210, and the storage unit 261 included in the photoelectric conversion element 10. The pixel 200, the pixel circuit 210, and the storage unit 261 constitute a pixel unit in the photoelectric conversion element 10. The photoelectric conversion element 10 has, for example, about 7000 pixel portions for each color. That is, the photoelectric conversion element 10 includes about 7000 pixels 200 and about 7000 pixel circuits 210 for each RGB color, and the AMEM 26 has about 7000 storage units 261 for each RGB color.

  The pixel 200 includes a PD (photodiode: light receiving element) that photoelectrically converts incident light. The PD outputs the accumulated charge to the pixel circuit 210. The pixel circuit 210 includes a floating diffusion (FD: charge-voltage conversion circuit) that performs charge-voltage conversion, a reset transistor that resets the FD, a transfer transistor that transfers the charge of the PD to the FD, and buffers and outputs a signal to the subsequent stage. Has a source follower (SF). A signal from the SF is read out to the subsequent stage through a read wiring. That is, SF is a buffer unit that buffers and outputs a voltage signal corresponding to the charge generated by the PD. A storage unit 261 is connected to the subsequent stage of the pixel circuit 210.

  The storage unit 261 includes a selection switch (SL) that selects the pixel 200, a current source (Is) that supplies a bias current to SF, a selection switch (S) that selects the storage unit 261, and a memory capacity (analog memory: Cs). Have The storage unit 261 outputs a signal to the above-described AD converter. The current source (Is) is a current control circuit that controls the current flowing through the buffer unit to have a predetermined amount when the buffer unit outputs a voltage signal.

  The photoelectric conversion element 10 is a global shutter in which the writing operation to the memory capacity (Cs) is performed simultaneously for all the RGB pixels, but after the reading operation from the memory capacity (Cs), the RGB three pixels are sequentially added. Serial processing is read out to the subsequent stage.

  FIG. 3 is a diagram schematically illustrating a configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10. Note that, in the photoelectric conversion element 10, the pixels 200 and the like that are provided with different color filters and receive different colors are distinguished from the pixels 200r, 200g, and 200b, respectively. In addition, when any one of the pixel 200r, the pixel 200g, the pixel 200b, and the like is not specified, the pixel 200r is simply described.

  In the photoelectric conversion element 10, the pixels 200 are arranged in one direction for each of RGB colors. The pixels 200 are arranged such that the interval between the pixels 200 that receive different colors corresponds to the two-pixel interval (2 line pitch: 1 line gap) of the image when the imaging target is imaged. This is because the pixel circuit 210 is disposed between the PDs of the respective colors.

  As described above, the photoelectric conversion element 10 reads the same document (subject) in RGB, but the RGB pixel 200 has an independent configuration for each color. In other words, since the RGB pixel row has an independent configuration for each color, it is possible to read RGB independently by shifting the time (timing) for reading the same document position in RGB.

  However, as described above, reading different document positions in RGB at the same time causes a color shift of the read image. This is because there are temporal variation factors such as vibration and document deflection associated with the scanning operation during document reading. That is, the reading conditions when reading the same document position for each RGB color are not completely equivalent, and this causes problems such as RGB color misregistration and coloring. In particular, the influence becomes more remarkable as the line pitch of the RGB pixel row is wider.

  Note that the above-described color shift is unique to a linear sensor that presupposes that the subject and the photoelectric conversion element 10 are scanned relatively, and does not cause a problem in the area sensor. This is because the area sensor normally reads different object positions in RGB due to its structure. That is, in an area sensor, it is normal to perform image correction at a later stage on the assumption that there is a color shift originally in the structure.

  FIG. 4 is a diagram illustrating the influence of color misregistration on the entire document. FIG. 5 is a diagram showing the effect of color misregistration on the upper part of black characters written on a document. As shown in FIG. 3, in the photoelectric conversion element 10, the time when the same document position is read is different for RGB. In the configuration shown in FIG. 3, since the RGB pixel row has a two-line pitch, each of the RGB pixels 200 sequentially reads a position shifted by two lines, and as shown in FIG. Each will be different by two lines.

  Here, in a scanner, it is general that the difference between reading lines between RGB is corrected by an inter-line correction unit or the like in the subsequent stage to synthesize RGB. For example, when attention is paid to the upper part of black characters in FIG. 4 (inside the dotted circle), at the time of scanning, it is first read by the R pixel row, then read by the G pixel row after 2 lines, and further read by the B pixel row after 2 lines. At this time, if there is no particular change, RGB can read the document as usual (FIG. 5A).

  However, for example, when vibration at the time of scanning occurs at the timing of t1 read by the R pixel row and t7 read by the B pixel row, the read level of R / B changes. Therefore, after RGB composition, the portion where the R / B level has changed is colored, and black characters can no longer be reproduced in FIG. 5B.

  As described above, the photoelectric conversion element 10 has a problem of color misregistration caused by different timings of reading the same document position in RGB. In particular, since the influence of color misregistration becomes more prominent as the line pitch of the pixel column increases, it is important to narrow the RGB pixel column. 4 and 5 show examples in which the document is read in the order of R → G → B, but in the opposite case, R and B may be considered in reverse.

  On the other hand, when the photoelectric conversion element 10 is disposed so that the pixel 200 and the pixel circuit 210 are adjacent to each other as illustrated in FIG. 3, the occurrence of parasitic capacitance between the pixel 200 and the pixel circuit 210 is suppressed. Therefore, the sensitivity can be increased.

(First embodiment)
FIG. 6 is a diagram schematically illustrating a configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element according to the first embodiment. Of the components shown in FIG. 6 and the like, the same components as those shown in FIG. 3 and the like are denoted by the same reference numerals. Moreover, the photoelectric conversion element concerning the following embodiment may be described as the photoelectric conversion element 10a. The photoelectric conversion element 10a may have the same configuration as the photoelectric conversion element 10 illustrated in FIG. 1 except for the configuration described below.

  As shown in FIG. 6, the photoelectric conversion element 10a is different from the arrangement of the pixel 200 and the pixel circuit 210 shown in FIG. 3 in that each pixel circuit 210 is formed in a region different from the region occupied by each pixel 200. Yes. Specifically, the photoelectric conversion element 10 a includes a photoelectric conversion unit 40 and a circuit unit 42.

  The photoelectric conversion unit 40 includes a plurality of pixels 200 that are arranged in one direction for each color to receive light and accumulate charges by exposure. That is, in the photoelectric conversion unit 40, a plurality of light receiving element arrays in which a plurality of PDs (light receiving elements) are arranged in one direction are provided for each color of light received. The circuit unit 42 includes a plurality of pixel circuits 210 each formed with an FD that is formed in a region different from the region occupied by the photoelectric conversion unit 40 and converts charges accumulated in the pixels 200 into voltages. More specifically, the circuit unit 42 is formed in a region aligned in the two-dimensional direction with respect to the photoelectric conversion unit 40. In addition, the PD of each pixel 200 is arranged so that the interval between other PDs having different colors to be received corresponds to the pixel interval (one line) of the image when the imaging target is imaged.

  That is, according to the configuration shown in FIG. 6, the photoelectric conversion element 10a has a one-line gap configuration in which RGB pixel columns are arranged adjacent to each other, and the influence of color misregistration can be reduced.

  In general, the pixel circuit 210 is disposed close to the PD. This is because if the distance between the PD and the pixel circuit is increased, the FD capacitance increases due to the wiring capacitance and the like, and the sensitivity decreases. However, unlike an area sensor, a linear sensor has only a few lines of pixel columns (the area sensor has several thousand lines), so even if the pixel circuit 210 is provided outside the pixel column, The distance is short and the effect of sensitivity reduction is small.

  In the linear sensor, for example, since there are only about three RGB pixel rows, an arbitrary region can be provided in the sub-scanning direction orthogonal to the pixel row direction. In the area sensor, since the pixels are laid out two-dimensionally, the configuration as shown in FIG. 6 cannot be adopted.

  Therefore, by providing the pixel circuit 210 outside the pixel region in the direction orthogonal to the direction of the pixel column, the adjacent arrangement of the pixels 200 shown in FIG. 6 can be easily realized. Further, in the linear sensor, since the processing circuit in the subsequent stage is arranged in a direction orthogonal to the direction of the pixel column, it becomes possible to use the chip space efficiently. Therefore, the output signal from the pixel circuit 210 is For example, it is output in a direction orthogonal to the direction of the pixel column.

  FIG. 7 is a diagram showing the effect of reducing the color misregistration of the entire document by the configuration shown in FIG. FIG. 8 is a diagram showing the effect of reducing color misregistration in the upper part of black characters written on a document. As described above, in the configuration shown in FIG. 6, the pixel columns of the respective colors are arranged adjacent to each other, so that the influence of color misregistration is reduced.

  FIG. 7 shows the read timing of the RGB image, but the shift of the image that was shifted by two lines in FIG. 4 is one line. Further, FIG. 5B shows a case where the level changes at the timing of t1 / t7, but FIG. 8B shows that the line pitch of the pixel column has been changed from 2 to 1 line, so that at t7. Level fluctuation, that is, no influence on the B pixel column occurs. For this reason, the influence of the level fluctuation remains only at t1, that is, the R pixel row, and after the RGB composition, only the uppermost portion needs to be colored as shown in FIG. 8B.

  Thus, since the photoelectric conversion element 10a has the circuit unit 42 formed in a region different from the region occupied by the photoelectric conversion unit 40, it is possible to reduce the color shift of the read image. Here, a configuration in which priority is given to reducing the color misregistration of the read image is shown, but in the case of improving specific characteristics such as sensitivity, the photoelectric conversion element is configured according to the priority characteristics. A partial change in the arrangement of each unit may be combined.

(Second Embodiment)
FIG. 9 is a diagram schematically illustrating a configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the second embodiment. As illustrated in FIG. 9, the photoelectric conversion element 10 a according to the second embodiment includes a condensing unit 44 such as a microlens, and is provided so that the condensing unit 44 is adjacent. The condensing unit 44 condenses the light passing through the opening 440 provided for each pixel 200 on the pixel 200. In the configuration illustrated in FIG. 9, the pixel 200 and the pixel circuit 210 are disposed in the region of the pixel 200 illustrated in FIG. 3.

  In the second embodiment, since the condensing unit 44 condenses the light passing through the opening 440, the pixel 200 and the pixel circuit 210 are disposed adjacent to each other. As a result, the influence of color misregistration is reduced while suppressing a decrease in sensitivity. In addition, the condensing part 44 is not limited to a microlens, The other structure which condenses on the pixel 200 may be sufficient.

(Third embodiment)
FIG. 10 is a diagram schematically illustrating a configuration of a photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the third embodiment. In the third embodiment, the circuit unit 42 is formed in a region overlapping with the photoelectric conversion unit 46 in the stacking direction, as shown in FIG.

  FIG. 10A shows a configuration viewed in the XY plane (two-dimensional direction) around the pixel column included in the photoelectric conversion element 10a according to the third embodiment. The photoelectric conversion unit 46 includes, for example, a plurality of organic photoelectric conversion thin film (OPF) 202.

  The OPF 202 is generally a material of a solar cell, and although the principle is different from that of the PD, the photoelectric conversion can be performed in the same manner as the PD. Specifically, the OPF 202 can generate an image signal by connecting the electrodes and extracting charge. Therefore, it is currently attracting attention as a next-generation photoelectric conversion element that replaces PD.

  In addition, since the OPF 202 is an organic material, it can be applied onto a semiconductor chip by spin coating, similar to a color filter. This means that it is not necessary to generate a part of the circuit on the Si substrate as in the case of the conventional PD. The pixel circuit 210 is formed on the Si substrate (circuit), and the OPF 202 is formed on the upper part. It can be arranged. That is, the photoelectric conversion unit 40 and the circuit unit 42 can be stacked in the depth direction, and can be arranged in a three-dimensional direction.

  Furthermore, if the OPF 202 is used for the photoelectric conversion unit 40 of the photoelectric conversion element 10a, the photoelectric conversion unit 40 can be disposed on the semiconductor chip, that is, the uppermost layer above the Si substrate or wiring as described above. Shading due to optical vignetting, which is a problem in the case of an optical system with a wide angle of view, can be suppressed.

(Fourth embodiment)
FIG. 11 is a diagram schematically illustrating a configuration of a photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the fourth embodiment. In the fourth embodiment, the aperture of the pixel 200 that is the light incident area is common to RGB, and light of three colors of RGB can be detected from the light incident on the area of one pixel 200. The influence is suppressed in principle.

  In the photoelectric conversion element 10a according to the fourth embodiment, a pixel 200 and a pixel circuit 210 are provided for each RGB color, but each pixel 200g and each pixel 200b are shielded from light by a light shielding member 48, and each pixel 200r. Only the light that has passed through the opening is incident.

  FIG. 11B shows a cross section in the y direction. A color separation element 480r for separating R and G / B is formed above the pixel 200r, and G and B are above the pixel 200g. A color separation element 480g that performs the above-described separation is formed, and an in-layer mirror 480b serving as a complete reflection surface is formed above the pixel 200b.

  FIG. 11B shows a state where light is incident. The light incident through the opening formed on the R pixel column (pixel 200r) is first divided into R and G / B by the R color separation element 480r. Here, the transmission component is R and the reflection component is G / B. The separated R is directly incident on the PD of the pixel 200r. The separated G / B component is further separated into G / B by another color separation element 480g. Here, the transmission component is B and the reflection component is G. The separated G component is incident on the PD of the pixel 200g, and the B component is incident on the PD of the pixel 200b via the in-layer mirror 480b.

  As described above, it is possible to simultaneously detect RGB light from the reflected light from the same document position by color-separating the light incident from the opening of the common pixel into RGB. That is, in the fourth embodiment, since the same document position is not read at different timings for RGB, the influence of color misregistration can be suppressed in principle.

  In addition, since the linear sensor has only three pixel rows of RGB, RGB PDs are arranged in the sub-scanning direction orthogonal to the direction of the pixel row, so that RGB light is simultaneously transmitted from the light passing through the opening of the same pixel. Detection can be easily realized. In FIG. 11, an opening is provided above the R pixel column (pixel 200r) and color separation is performed for RGB, but the position where the opening is provided may be the G pixel column or the B pixel column. In the fourth embodiment, the color separation element 480r, the color separation element 480g, and the in-layer mirror 480b are used as an example. However, the color separation may be performed by changing the prism or the refractive index distribution. Good.

  FIG. 12 is a diagram showing the effect of reducing the color misregistration of the entire document by the configuration shown in FIG. FIG. 13 is a diagram showing the effect of reducing color misregistration in the upper part of black characters written on a document. In FIG. 12, the RGB image reading timing is shown, but the image shift that was shifted by 2 lines in FIG. 4 is 0 line. That is, there is no image shift.

  Specifically, when there is a level change at the timing of t1 / t7, the color shift shown in FIG. 5B is that the line pitch of the pixel row is changed from 2 to 0 in FIG. 13B. Therefore, the level fluctuation at t7, that is, the influence on the B pixel column does not occur. For this reason, the influence of the level fluctuation remains only at t1, but since the reading is performed for all the RGB pixel columns at the timing of t1, the influence appears on all the RGB. Therefore, after RGB composition, the level fluctuation occurs only at the top as shown in FIG. 8B, but since all the RGB changes the same, coloring can be suppressed.

(Fifth embodiment)
FIG. 14 is a diagram schematically illustrating a configuration of a photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the fifth embodiment. The photoelectric conversion element 10a according to the fifth embodiment includes an absorption / transmission type organic photoelectric conversion thin film (OPF), and performs RGB simultaneous detection to suppress color misregistration in principle.

  In the configuration illustrated in FIG. 14, the OPF 202g, OPF 202b, OPF 202r, and the pixel circuit 210g are stacked at the same position, and the pixel circuit 210b and the pixel circuit 210r are arranged in the pixel circuit 210g.

  Here, utilizing the fact that the dye-sensitized OPF can have arbitrary spectral characteristics, the OPF 202 is provided with an RGB color separation function. Further, since OPF has absorption / transmission type color separation characteristics that absorb light to be photoelectrically converted and transmit other light, a stacked structure as shown in FIG. 14 is possible. Each OPF 202 is connected to the pixel circuit 210 for each color. Further, when photoelectric conversion is performed by the OPF 202, shading due to optical vignetting, which is a problem in the case of a wide-angle optical system, can be suppressed.

  As described above, in the configuration shown in FIG. 14, RGB can be simultaneously detected from light from the same document position by stacking absorption / transmission type OPFs, so that the effect of color misregistration is suppressed in principle. It is possible.

  In the arrangement in which the OPFs 202 for detecting RGB are stacked, in the image reading device, strictly speaking, the positional relationship with the imaging lens differs between RGB, so the magnification and focus position change for each color. However, since the OPF 202 has a thickness of several hundred nm to several um, there is no particular problem in practical use. In FIG. 14B, the OPF 202g is arranged at the uppermost part in consideration of color reproducibility, but the OPF 202r or the OPF 202b may be arranged at the uppermost part. Further, the arrangement of the pixel circuits 210 is not limited to the position shown in FIG.

(Modification of the fifth embodiment)
FIG. 15 is a diagram schematically illustrating a configuration of a photoelectric conversion region 20 (around the pixel column) included in a modification of the photoelectric conversion element 10a according to the fifth embodiment. The photoelectric conversion element 10a according to the fifth embodiment is configured to perform photoelectric conversion using the OPF 202 for all three colors of RGB. However, in a modification of the photoelectric conversion element 10a according to the fifth embodiment, as shown in FIG. Is replaced with the pixel 200r having a PD and used in combination with the OPF 202g and the OPF 202b. Even in this case, RGB stacked arrangement is possible. Note that the OPF 202g and OPF 202b are not connected to the pixel 200r, but are connected to the corresponding pixel circuit 210g and pixel circuit 210b, respectively. The pixel 200r is connected to the pixel circuit 210r.

  Next, an image forming apparatus including an image reading apparatus having the photoelectric conversion element 10a according to any of the embodiments will be described. FIG. 16 is a diagram illustrating an outline of an image forming apparatus 50 including an image reading device 60 having the photoelectric conversion element 10a. The image forming apparatus 50 is, for example, a copying machine or an MFP (Multifunction Peripheral) having an image reading device 60 and an image forming unit 70.

  The image reading device 60 includes, for example, a photoelectric conversion element 10a, an LED driver (LED_DRV) 600, and an LED 602. The LED driver 600 drives the LED 602 in synchronization with a line synchronization signal output from the timing control unit (TG) 30. The LED 602 irradiates the original with light. The photoelectric conversion element 10a receives reflected light from a document in synchronization with a line synchronization signal or the like, and a plurality of light receiving elements (PD) generate electric charges and start accumulation. The photoelectric conversion element 10a outputs image data to the image forming unit 70 through the LVDS 29 after performing AD conversion, parallel serial conversion, and the like.

  The image forming unit 70 includes a processing unit 80 and a printer engine 82, and the processing unit 80 and the printer engine 82 are connected via an interface (I / F) 84.

  The processing unit 80 includes an LVDS 800, an image processing unit 802, and a CPU 804. The CPU 804 controls each part of the image forming apparatus 50 such as the photoelectric conversion element 10a. In addition, the CPU 804 (or the timing control unit 30) controls each PD to start generating charges according to the amount of received light substantially simultaneously.

  The LVDS 29 outputs, for example, image data of an image read by the image reading device 60, a line synchronization signal, a transmission clock, and the like to the LVDS 800 at the subsequent stage. The LVDS 800 converts received image data, a line synchronization signal, a transmission clock, and the like into parallel 10-bit data. The image processing unit 802 performs image processing using the converted 10-bit data, and outputs image data and the like to the printer engine 82. The printer engine 82 performs printing using the received image data.

10, 10a Photoelectric conversion element 20 Photoelectric conversion region 26 AMEM
27 ADC
28 P / S
29 LVDS
30 TG
40, 46 Photoelectric conversion unit 42 Circuit unit 44 Condensing unit 48 Light shielding member 50 Image forming device 60 Image reading device 70 Image forming unit 200 Pixel 202 OPF
210 Pixel circuit 480r, 480g Color separation element 480b In-layer mirror

Japanese Patent Laid-Open No. 08-293967

Claims (7)

A photoelectric conversion unit in which a plurality of light receiving element arrays in which a plurality of light receiving elements that accumulate electric charge by exposure are arranged in one direction is provided for each color to be received;
A circuit unit including a plurality of charge-voltage conversion circuits that are formed in a region different from a region occupied by the photoelectric conversion unit and convert charges accumulated in the plurality of light receiving elements into voltages, respectively;
A photoelectric conversion element comprising: The circuit section is
The photoelectric conversion element according to claim 1, wherein at least part of the photoelectric conversion element is formed in a region aligned in a two-dimensional direction with respect to the photoelectric conversion unit. The circuit section is
The photoelectric conversion element according to claim 1, wherein at least a part is formed in a region overlapping with the photoelectric conversion unit in a stacking direction. The light receiving element is
4. The device according to claim 1, wherein an interval between the other light receiving elements having different colors for receiving light is arranged so as to correspond to a pixel interval of an image when an imaging target is imaged. The photoelectric conversion element as described in 2. The light receiving element is
5. The photoelectric conversion element according to claim 1, wherein at least one is an organic photoelectric conversion thin film. An image reading apparatus comprising the photoelectric conversion element according to claim 1. An image reading apparatus according to claim 6;
An image forming apparatus comprising: an image forming unit that forms an image based on an output of the image reading apparatus.

Images