JP6701772B2 - Photoelectric conversion element, image reading apparatus, and image forming apparatus - Google Patents

Description

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

  A color scanner reads an image by scanning a document, but there is a problem that a color shift (a shift in hue relative to the original color) occurs due to 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, this is because the same document position is read by different pixels and the read timing is different for each color.

  In order to solve the above-mentioned problem, for example, in Japanese Patent Laid-Open No. 2004-242242, 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 photosensitive pixel column of an image sensor provided with a horizontal transfer register outside thereof There is disclosed an image sensor in which a storage unit for saving the signal charge of each pixel is arranged between the image sensor and a horizontal transfer register.

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

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

In order to solve the above-mentioned problems and to achieve the object, according to the present invention, a plurality of light receiving element rows in each of which a plurality of light receiving elements for accumulating charges by exposure are arranged in one direction are provided for each color to be received. a photoelectric conversion unit, the are formed in a region different from the photoelectric conversion unit occupied area, and a circuit portion including only a plurality of charge-to-voltage conversion circuit for converting charges plurality of said light receiving element is accumulated in each voltage, the Have.

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

FIG. 1 is a diagram illustrating the overall configuration of a photoelectric conversion element. FIG. 2 is a diagram showing a configuration of a pixel, a pixel circuit, and a storage unit included in the photoelectric conversion element. FIG. 3 is a diagram schematically showing a configuration of a photoelectric conversion region included in the photoelectric conversion element. FIG. 4 is a diagram showing the influence of color misregistration of the entire document. FIG. 5 is a diagram showing the influence of color misalignment at the upper part of black characters written on a document. FIG. 6 is a diagram schematically showing 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 the color misregistration in the upper part of the black characters written on the document. FIG. 9: is a figure which shows typically the structure of the photoelectric conversion area|region which the photoelectric conversion element concerning 2nd Embodiment has. FIG. 10: is a figure which shows typically the structure of the photoelectric conversion area|region which the photoelectric conversion element concerning 3rd Embodiment has. FIG. 11 is a diagram schematically showing the 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 the color misregistration in the upper part of the black characters written on the document. FIG. 14: is a figure which shows typically the structure of the photoelectric conversion area|region which the photoelectric conversion element concerning 5th Embodiment has. FIG. 15: is a figure which shows typically the structure of the photoelectric conversion area|region which the modification of the photoelectric conversion element concerning 5th Embodiment has. FIG. 16 is a diagram showing an outline of an image forming apparatus provided with an image reading apparatus having a photoelectric conversion element.

  First, the background leading to the present invention will be described. As a photoelectric conversion element used in a scanner, a CCD has been widely used in the past, but in recent years, a CMOS linear sensor has attracted attention due to a demand for higher speed. A CMOS linear sensor is the same as a CCD in that incident light is photoelectrically converted by a photodiode (PD), but it is different in that it performs charge-voltage conversion near a pixel and outputs it to the subsequent stage.

  FIG. 1 is a diagram illustrating an overall configuration of a CMOS color linear image sensor (photoelectric conversion element) 10. The photoelectric conversion region 20 is provided with about 7,000 PDs (photodiodes: light receiving elements) for each of the colors RGB. The PDs are arranged in one direction for each color of the received light and generate electric charges according to the amount of received light. Further, each PD is provided with a pixel circuit. That is, the photoelectric conversion area 20 is also provided with about 7,000 pixel circuits for each of the colors RGB.

  Each pixel circuit converts the charge accumulated in the PD into a voltage signal, and outputs the signal to the analog memory through the read line. The pixel circuit includes a transfer transistor that transfers the charge of 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 the FD voltage to the read line. Unlike the area sensor, the linear sensor reads out signals from each of the RGB pixels independently, so that the readout line exists independently for each pixel.

  The AMEM 26 has, for example, about 7,000 analog memories (for example, Cs described later) for each of RGB colors, holds a signal for each pixel, and displays an image on a column-by-column basis with three RGB pixels as one pixel group. The signals are output sequentially. By the AMEM 26 holding the signal, a global shutter system is realized in which the operation timings of the PD and the pixel circuit, that is, the exposure timings are the same in RGB. Note that the photoelectric conversion element 10 shown in FIG. 1 is configured by a column in which three pixels of RGB are included in one pixel group, but it is sufficient that a plurality of pixels form one pixel group in the column. The number of pixels is not limited to three.

  The ADC 27 has the same number of AD converters as the number of columns, and sequentially AD-converts the image signal in column units. 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 converters.

  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 by 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 obtained by performing parallel processing on 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 that constitutes the photoelectric conversion element 10.

  FIG. 2 is a diagram showing configurations 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 form a pixel unit in the photoelectric conversion element 10. The photoelectric conversion element 10 has, for example, about 7,000 pixel portions for each color. That is, the photoelectric conversion element 10 includes about 7,000 pixels 200 and about 7,000 pixel circuits 210 for each color of RGB, and the AMEM 26 has about 7,000 storage units 261 for each color of RGB.

  The pixel 200 has 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 has 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 a signal that is buffered and output to the subsequent stage. It has a source follower (SF). The signal from SF is read out to the subsequent stage via the read wiring. That is, the SF serves as a buffer unit that buffers and outputs the voltage signal according to the charges generated by the PD. Further, the 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 the 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 AD converter described above. The current source (Is) is a current control circuit that controls the current flowing through the buffer unit to a predetermined amount when the buffer unit outputs a voltage signal.

  Note that the photoelectric conversion element 10 is a global shutter in which the writing operation to the memory capacity (Cs) simultaneously operates for all the RGB pixels, but the RGB 3 pixels are sequentially read after the reading operation from the memory capacity (Cs). It is a serial process that is read out at a later stage.

  FIG. 3 is a diagram schematically showing a configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10. In the photoelectric conversion element 10, the pixels 200 and the like provided with different color filters and having different received colors are distinguished from the pixels 200r, 200g, and 200b, respectively. Further, when any one of the pixel 200r, the pixel 200g, the pixel 200b, and the like is not specified, it is simply referred to as the pixel 200 and the like.

  In the photoelectric conversion element 10, the pixels 200 are arranged in one direction for each color of RGB. The pixel 200 is arranged such that the interval between the pixel 200 and another pixel 200 having a different color to be received corresponds to a two-pixel interval (2 line pitch: 1 line gap) of an image when an image pickup target is picked up. This is because the pixel circuit 210 is arranged between the PDs of the respective colors.

  As described above, the photoelectric conversion element 10 reads the same original document (subject) in RGB, but the RGB pixel 200 has an independent structure for each color. In other words, since the RGB pixel rows are configured to be independent for each color, RGB can be read 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 color misregistration of the read image. This is because there are time-varying factors such as vibrations and document bending that accompany the scanning operation during document reading. That is, this is because the reading conditions when reading the same document position in each of the RGB colors are not completely equivalent, which causes problems such as RGB color misregistration and coloring. In particular, the wider the line pitch of the RGB pixel row, the more remarkable the effect.

  The above-mentioned color shift is peculiar to the linear sensor, which is premised on relatively scanning the subject and the photoelectric conversion element 10, 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 the area sensor, it is usual to perform image correction in the subsequent stage on the assumption that there is originally a color shift due to its structure.

  FIG. 4 is a diagram showing the influence of color misregistration of the entire document. FIG. 5 is a diagram showing the influence of color misalignment at 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 differs for RGB. In the configuration shown in FIG. 3, since the RGB pixel row has a two-line pitch, the RGB pixels 200 sequentially read positions shifted by two lines, and as shown in FIG. Each will differ by two lines.

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

  However, for example, when vibration during scanning occurs at the timing of t1 which is read by the R pixel row and t7 which is read by the B pixel row, the read level of R/B changes. Therefore, after RGB combination, the portion where the R/B level has changed becomes 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 due to different timings of reading the same document position in RGB. In particular, the influence of color misregistration becomes more significant as the line pitch of the pixel rows increases, so it is important to make the RGB pixel rows a narrow pitch. Although FIG. 4 and FIG. 5 show an example of reading a document in the order of R→G→B, in the opposite case, R and B may be considered in reverse.

  On the other hand, in the photoelectric conversion element 10, when the pixel 200 and the pixel circuit 210 are arranged adjacent to each other as shown in FIG. 3, parasitic capacitance is suppressed from occurring between the pixel 200 and the pixel circuit 210. Therefore, the sensitivity can be increased.

(First embodiment)
FIG. 6 is a diagram schematically showing the configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element according to the first embodiment. Note that, of the constituent parts shown in FIG. 6 and the like, those substantially the same as the constituent parts shown in FIG. 3 and the like are designated by the same reference numerals. Further, the photoelectric conversion element according to the following embodiments may be referred to as a photoelectric conversion element 10a. The photoelectric conversion element 10a may have the same configuration as the photoelectric conversion element 10 shown 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 pixels 200 and the pixel circuits 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. There is. Specifically, the photoelectric conversion element 10a includes a photoelectric conversion unit 40 and a circuit unit 42.

  The photoelectric conversion unit 40 has a plurality of pixels 200 arranged in one direction for each color of light received and accumulating charges by exposure. That is, in the photoelectric conversion unit 40, a plurality of light receiving element rows in which a plurality of PDs (light receiving elements) are arranged in one direction are provided for each color to be received. The circuit unit 42 has 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 that converts an electric charge accumulated in each pixel 200 into a voltage. More specifically, the circuit section 42 is formed in a region lined up in the two-dimensional direction with respect to the photoelectric conversion section 40. In addition, the PD of each pixel 200 is arranged such that the interval between the PD and the other PDs that receive different colors corresponds to the pixel interval (1 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.

  Note that the pixel circuit 210 is generally arranged close to the PD. This is because when the distance between the PD and the pixel circuit increases, the FD capacitance increases due to the wiring capacitance and the like, and the sensitivity decreases. However, unlike the area sensor, the linear sensor has only a few rows of pixel rows arranged at most (thousands of lines are arranged in the area sensor). Therefore, even if the pixel circuit 210 is provided outside the pixel row, The distance is short and the effect of sensitivity reduction is small.

  Further, in the linear sensor, for example, the number of pixel rows is only three, that is, RGB, so that it is possible to provide an arbitrary area in the sub-scanning direction orthogonal to the direction of the pixel rows. In the area sensor, the pixels are two-dimensionally laid out, so that the configuration 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 the direction orthogonal to the direction of the pixel column, it is possible to efficiently use the chip space, so that the output signal from the pixel circuit 210 is For example, it is output in the 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 the color misregistration in the upper part of the black characters written on the document. As described above, in the configuration shown in FIG. 6, since the pixel columns of the respective colors are arranged adjacent to each other, the influence of color misregistration is reduced.

  In FIG. 7, the reading timing of the RGB image is shown, but the shift of the image, which is shifted by 2 lines in FIG. 4, is 1 line. Further, FIG. 5B shows the case where there is a level change at the timing of t1/t7. However, in FIG. 8B, the line pitch of the pixel column is changed from 2 to 1 line, so that at t7. The level variation, that is, the influence on the B pixel column does not occur. Therefore, the influence of the level change remains at t1, that is, only in the R pixel column, and after RGB combination, only the uppermost part is colored as shown in FIG. 8B.

  As described above, in the photoelectric conversion element 10a, since the circuit section 42 is formed in a region different from the region occupied by the photoelectric conversion unit 40, it is possible to reduce the color misregistration of the read image. Here, the configuration is shown in which priority is given to reducing the color misregistration of the read image. However, in the case of improving a specific characteristic such as sensitivity, the photoelectric conversion element is configured according to the priority characteristic. Partial changes in the arrangement of the respective units may be combined.

(Second embodiment)
FIG. 9 is a diagram schematically showing the configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the second embodiment. As shown in FIG. 9, the photoelectric conversion element 10a according to the second embodiment has a condensing part 44 such as a microlens, and the condensing parts 44 are provided adjacent to each other. The light condensing unit 44 condenses light passing through the opening 440 provided for each pixel 200 on the pixel 200. In the configuration shown in FIG. 9, the pixel 200 and the pixel circuit 210 are arranged in the area of the pixel 200 shown in FIG.

  In the second embodiment, the light collector 44 collects the light passing through the opening 440, so that the pixel 200 and the pixel circuit 210 are arranged so as to be adjacent to each pixel. As a result, the sensitivity deterioration is suppressed and the influence of color misregistration is reduced. The condensing unit 44 is not limited to a microlens, and may have another configuration that condenses on the pixel 200.

(Third Embodiment)
FIG. 10 is a diagram schematically showing the configuration of the 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 section 42 is formed in a region overlapping the photoelectric conversion section 46 in the stacking direction, as shown in FIG.

  FIG. 10A shows the configuration seen 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 films (OPF; Organic-Photoelectric-conversion-Film) 202.

  The OPF 202 is generally a material for solar cells, and although the principle is different from PD, it can perform photoelectric conversion in the same manner as PD. Specifically, the OPF 202 can generate an image signal by connecting an electrode and extracting an electric charge. Therefore, it is currently receiving attention as a next-generation photoelectric conversion element that can replace PD.

  Further, the OPF 202 has the greatest feature in that it can be applied on the semiconductor chip by spin coating similarly to the color filter, since it is an organic material. This means that it is not necessary to generate it as a part of the circuit on the Si substrate unlike the conventional PD, and the pixel circuit 210 is formed on the Si substrate (circuit), and the OPF 202 is formed on the pixel circuit 210. It is possible to arrange them. That is, the photoelectric conversion unit 40 and the circuit unit 42 can be stacked in the depth direction, and the three-dimensional arrangement is possible.

  Furthermore, if the OPF 202 is used for the photoelectric conversion section 40 of the photoelectric conversion element 10a, the photoelectric conversion section 40 can be arranged on the semiconductor chip, that is, in the uppermost layer above the Si substrate and the wiring, as described above. Shading due to light 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 the configuration of the 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 opening of the pixel 200, which is a light incident area, is common to RGB, and the light of three colors RGB can be detected from the light incident on the area of one pixel 200, and the color misregistration occurs. The effect is suppressed in principle.

  In the photoelectric conversion element 10a according to the fourth embodiment, the pixel 200 and the pixel circuit 210 are provided for each color of RGB, but each pixel 200g and each pixel 200b are shielded by the 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 that separates R and G/B is formed above the pixel 200r, and G and B are formed above the pixel 200g. A color separation element 480g that separates the image is formed, and an in-layer mirror 480b that serves as a perfect reflection surface is formed above the pixel 200b.

  Further, FIG. 11B shows how light is incident. Light incident through the opening formed on the R pixel column (pixel 200r) is first separated 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 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 separated B component is incident on the PD of the pixel 200b via the intra-layer mirror 480b.

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

  Further, since the linear sensor has only three RGB pixel rows, the RGB PDs are arranged in the sub-scanning direction orthogonal to the pixel row direction, so that the light passing through the openings of the same pixel can be simultaneously converted to RGB. The detection can be easily realized. Note that in FIG. 11, an opening is provided above the R pixel column (pixel 200r) to perform color separation into RGB, but the position where the opening is provided may be the G pixel column or the B pixel column. Further, in the fourth embodiment, the case where the color separation element 480r, the color separation element 480g and the in-layer mirror 480b are used is taken as an example, but the color separation can 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 the color misregistration in the upper part of the black characters written on the document. Although the reading timing of the RGB image is shown in FIG. 12, the shift of the image, which is shifted by 2 lines in FIG. 4, is 0 line. That is, the image shift is eliminated.

  Specifically, when there is a level change at the timing of t1/t7, the color misregistration shown in FIG. 5B is that the line pitch of the pixel row is 2→0 line in FIG. 13B. Therefore, the level change at t7, that is, the influence on the B pixel column does not occur. Therefore, the influence of the level change remains only at t1, but at the timing of t1, since the reading is performed in all the RGB pixel columns, the influence appears in all RGB. Therefore, after RGB combination, a level change occurs only in the uppermost part as shown in FIG. 8B, but since all RGB have the same change, coloring can be suppressed.

(Fifth Embodiment)
FIG. 14 is a diagram schematically showing the configuration of the photoelectric conversion region 20 (around the pixel column) included in the photoelectric conversion element 10a according to the fifth embodiment. In the photoelectric conversion element 10a according to the fifth embodiment, absorption/transmission type organic photoelectric conversion thin films (OPF) are laminated, and RGB simultaneous detection is performed to theoretically suppress color misregistration.

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

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

  In the arrangement in which the OPFs 202 for detecting RGB are stacked, the positional relationship with the image pickup lens in the image reading device is different in RGB, so that the magnification and the focus position are different for each color. However, since the OPF 202 has a thickness of several hundred nm to several um, it does not cause any particular problem in practical use. Further, in FIG. 14B, the OPF 202g is arranged at the uppermost part in consideration of the color reproducibility, but the OPF 202g or OPF 202b may be arranged at the uppermost part. Further, the arrangement of each pixel circuit 210 is not limited to the position shown in FIG.

(Modification of the fifth embodiment)
FIG. 15 is a diagram schematically showing the configuration of the photoelectric conversion region 20 (around the pixel column) included in the 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 by the OPF 202 for all three colors of RGB, but in the modification of the photoelectric conversion element 10a according to the fifth embodiment, as shown in FIG. Is replaced with the pixel 200r having PD and is used in combination with the OPF 202g and OPF 202b. Even in this case, the RGB stacked arrangement is possible. The OPF 202g and the OPF 202b are not connected to the pixel 200r but are connected to the corresponding pixel circuit 210g and the corresponding 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 showing an outline of the image forming apparatus 50 including the 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 apparatus 60 and an image forming unit 70.

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

  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 has an LVDS 800, an image processing unit 802, and a CPU 804. The CPU 804 controls each unit that constitutes the image forming apparatus 50 such as the photoelectric conversion element 10a. Further, the CPU 804 (or the timing control unit 30) controls the PDs to start generating charges according to the amount of received light substantially at the same time.

  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 in the subsequent stage. The LVDS 800 converts the received image data, line sync signal, transmission clock, etc. into parallel 10-bit data. The image processing unit 802 performs image processing using the converted 10-bit data and outputs the image data and the like to the printer engine 82. The printer engine 82 prints 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 section 42 Circuit section 44 Condensing section 48 Light blocking member 50 Image forming apparatus 60 Image reading apparatus 70 Image forming section 200 Pixel 202 OPF
210 pixel circuit 480r, 480g color separation element 480b in-layer mirror

JP, 08-293967, A

Claims (7)

A light-receiving element array in which a plurality of light-receiving elements that accumulate charges by exposure are arranged in one direction, a photoelectric conversion unit provided in a plurality of rows for each color to receive light,
Wherein it is formed in a region different from the photoelectric conversion unit occupied area, and a circuit portion including only a plurality of charge-to-voltage conversion circuit for converting charges plurality of said light receiving element is accumulated in the voltage, respectively,
A photoelectric conversion element comprising: The circuit section is
The photoelectric conversion element according to claim 1, wherein at least a part of the photoelectric conversion element is formed in a region arranged 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 of the photoelectric conversion element is formed in a region overlapping the photoelectric conversion unit in the stacking direction. The light receiving element is
4. An interval between the light receiving element and another light receiving element having a different color to be received is arranged so as to correspond to a pixel interval of an image when an image pickup target is picked up. The photoelectric conversion element described in 1. The light receiving element is
At least one is an organic photoelectric conversion thin film, The photoelectric conversion element of any one of Claim 1 thru|or 4 characterized by the above-mentioned. An image reading apparatus comprising the photoelectric conversion element according to claim 1. An image reading apparatus according to claim 6;
An image forming unit that forms an image based on the output of the image reading device.

Images