JP2006165663A - Image pickup apparatus, digital camera and color image data generating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate high-quality color image data in an image pickup apparatus including a hybrid solid-state image pickup element having a photoelectric conversion film on an upper layer and a photoelectric conversion element made of a silicon on a lower layer. <P>SOLUTION: This apparatus is provided with a solid-state image pickup element 100 including the photoelectric conversion film laminated on the upper part of a semiconductor substrate 1, a plurality of photoelectric conversion elements 2, 4 including two kinds of photoelectric conversion elements arranged on the semiconductor substrate 1, and detecting colors different from a color to be detected by the photoelectric conversion film, and a signal reading circuit arranged on the semiconductor substrate 1 and reading color signals corresponding to signal charges to be accumulated in the plurality of photoelectric conversion elements 2, 4 and the photoelectric conversion film to the outside; and a color signal generating means for generating a color signal forming one-pixel data on the basis of the signal charges to be accumulated in the plurality of photoelectric conversion elements 2, 4 and the signal charges to be accumulated in the same type of photoelectric conversion element arranged adjacently to the above photoelectric conversion elements. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device that images a subject and generates color image data.

  Conventionally, as a solid-state imaging device having a configuration that does not use a color filter, for example, a stacked solid-state imaging device described in Patent Document 1 has been proposed. In this stacked solid-state imaging device, photoelectric conversion films made of three organic materials that detect red (R), green (G), and blue (B) light are stacked above a semiconductor substrate, and signals generated in the respective films are stacked. The charge is stored in a storage diode formed on the semiconductor substrate, and the signal charge stored in the storage diode is read and transferred by a signal readout circuit such as a vertical CCD and a horizontal CCD formed on the semiconductor substrate. It has become. According to this multilayer solid-state imaging device, it is possible to improve light utilization efficiency, suppress false colors, and generate a high-quality color image.

  The stacked solid-state imaging device requires a contact wiring that connects one of the two electrode films sandwiching each photoelectric conversion film stacked above the semiconductor substrate and a storage diode formed on the semiconductor substrate. The material of the contact wiring is a metal such as tungsten, copper, molybdenum, etc., and a high temperature of 300 ° C. or higher is required to form a wiring structure. On the other hand, since the photoelectric conversion film laminated on the semiconductor substrate is made of an organic material, the performance is obviously deteriorated when exposed to a high temperature of 200 degrees or more. For example, the stacked solid-state imaging device repeats the manufacturing process of forming the photoelectric conversion film three times after forming the contact wiring, so that the performance of the photoelectric conversion film formed earlier depends on the temperature at which the contact wiring is formed. There was a problem that it deteriorated by.

  Therefore, as a solid-state imaging device that solves such a problem, a photoelectric conversion element made of silicon that detects R and B is integrated on a semiconductor substrate, and a photoelectric conversion made of an organic material that detects G above the semiconductor substrate. A hybrid type in which one film is stacked has been proposed (see, for example, Patent Document 2). Since this hybrid type solid-state imaging device does not deteriorate in performance even when silicon is at a high temperature of 300 ° C. or higher, after forming a lower layer portion (photoelectric conversion device or contact wiring) in a high temperature process first, a photoelectric conversion film is formed. It can be manufactured by forming by a low temperature process, and the performance deterioration of the photoelectric conversion film can be prevented.

JP 2002-83946 A JP2003-332551A (paragraph 0035)

  In the hybrid solid-state imaging device, the aperture ratio of the upper photoelectric conversion film is approximately 100%, but the aperture ratio of the lower photoelectric conversion element is lower than that of the upper photoelectric conversion film. Further, the amount of light that can enter the photoelectric conversion element in the lower layer is smaller than that in the upper layer of the photoelectric conversion film due to the influence of contact wiring connected to the photoelectric conversion film in the upper layer. For this reason, the signal charge generated in the upper photoelectric conversion film for a certain amount of light is greater than the signal charge generated in the lower layer photoelectric conversion element for a certain amount of light, resulting in sensitivity variations or lower layer There arises a problem that the SN of the signal obtained from the photoelectric conversion element of the part deteriorates.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus including a hybrid solid-state imaging device having a photoelectric conversion film in an upper layer portion and a photoelectric conversion element made of silicon in a lower layer portion. In the present invention, high-quality color image data can be generated.

  The imaging device of the present invention is an imaging device that images a subject to generate color image data, and is a photoelectric conversion film stacked above a semiconductor substrate, arranged on the semiconductor substrate, and detected by the photoelectric conversion film A plurality of photoelectric conversion elements including at least two types of photoelectric conversion elements for detecting a color different from a color, a signal charge formed on the semiconductor substrate and accumulated in the plurality of photoelectric conversion elements, and the photoelectric conversion film. Accumulated in a solid-state imaging device including a signal readout circuit that reads out a color signal corresponding to the generated signal charge to the outside, and a photoelectric conversion device corresponding to one pixel data of the color image data among the plurality of photoelectric conversion devices. Based on the signal charges and the signal charges accumulated in the photoelectric conversion elements that detect the same color as the photoelectric conversion elements arranged adjacent to the photoelectric conversion elements, And a color signal generating means for generating a color signal constituting the data.

  With this configuration, it is possible to increase the sensitivity of the generated color signal or improve the S / N, and it is possible to generate high-quality color image data.

  In the imaging apparatus according to the aspect of the invention, the color signal generation unit may detect a color signal corresponding to a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data, A color signal corresponding to the signal charge accumulated in the photoelectric conversion element that detects the same color as the conversion element is added at a predetermined ratio to generate a color signal constituting the one-pixel data.

  With this configuration, by performing signal processing on an analog or digital color signal, it is possible to increase the sensitivity of the color signal constituting the color image data or improve the S / N.

  In the imaging device according to the aspect of the invention, the signal readout circuit transfers a signal charge accumulated in the plurality of photoelectric conversion elements and a signal charge generated in the photoelectric conversion film in a specific direction on the semiconductor substrate, respectively. A horizontal transfer path for transferring the signal charge transferred from the vertical transfer path in a direction orthogonal to the specific direction, and an output unit for outputting a color signal corresponding to the signal charge transferred from the horizontal transfer path And the color signal generation means detects a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data and the same color as the photoelectric conversion element adjacent to the photoelectric conversion element. A color signal constituting the one-pixel data by driving the solid-state imaging device so that signal charges accumulated in the photoelectric conversion element are mixed in the vertical transfer path and the horizontal transfer path. Generated.

  With this configuration, by mixing the signal charges accumulated in the photoelectric conversion elements, it is possible to increase the sensitivity of the color signals constituting the color image data or improve the S / N.

  The imaging device of the present invention includes a signal charge storage unit in which the solid-state imaging device is provided on the semiconductor substrate and stores signal charges generated in the photoelectric conversion film. The row in which the photoelectric conversion elements are alternately arranged and the row in which the signal charge storage units are arranged are shifted in the row direction by approximately ½ pitch of the arrangement pitch of the photoelectric conversion elements and the signal charge storage units in the row direction. Are arranged.

  With this configuration, it is possible to employ a meandering vertical transfer path as the signal readout circuit, thereby increasing the signal charge transfer capacity. Therefore, the areas of the photoelectric conversion film and the photoelectric conversion element can be increased, and higher-quality color image data can be generated.

  The imaging device of the present invention includes a signal charge storage unit in which the solid-state imaging device is provided on the semiconductor substrate and stores signal charges generated in the photoelectric conversion film, and the plurality of photoelectric conversion devices and the signal charges The storage units are arranged in a square lattice pattern, and are arranged in a checkered pattern.

  With this configuration, high-resolution color image data can be generated.

  In the imaging device of the present invention, the signal readout circuit includes a MOS transistor and a signal line connected to the MOS transistor, and the plurality of photoelectric conversion elements are stacked in a depth direction of the semiconductor substrate. The at least two types of photoelectric conversion elements are arranged on the same plane of the semiconductor substrate.

  In the imaging device according to the aspect of the invention, the solid-state imaging device includes a plurality of microlenses for condensing light on each of the plurality of photoelectric conversion elements above the photoelectric conversion film.

  In the imaging apparatus according to the aspect of the invention, the solid-state imaging element includes a plurality of microlenses that collect light on each of the plurality of photoelectric conversion elements between the photoelectric conversion film and the plurality of photoelectric conversion elements.

  In the imaging apparatus of the present invention, the photoelectric conversion film detects green light, and the at least two types of photoelectric conversion elements include a photoelectric conversion element that detects red light and a photoelectric conversion element that detects blue light. Including.

  In the imaging apparatus of the present invention, the photoelectric conversion film is configured to include an organic material.

  The digital camera of the present invention performs imaging using the imaging device.

  The color image data generation method of the present invention is a color image data generation method for capturing a subject and generating color image data, a photoelectric conversion film stacked above a semiconductor substrate, arranged on the semiconductor substrate, and A plurality of photoelectric conversion elements including at least two types of photoelectric conversion elements for detecting a color different from the color detected by the conversion film, and a signal charge formed on the semiconductor substrate and accumulated in the plurality of photoelectric conversion elements And a photoelectric conversion element corresponding to one pixel data of the color image data among the plurality of photoelectric conversion elements of a solid-state imaging device including a signal readout circuit that reads out a color signal corresponding to a signal charge generated in the photoelectric conversion film. A signal charge accumulated in the conversion element and a signal accumulated in the photoelectric conversion element that detects the same color as the photoelectric conversion element arranged adjacent to the photoelectric conversion element. Based on the charge, having a color signal generating step of generating a color signal constituting the one pixel data.

  In the color image data generation method of the present invention, the color signal generation step includes a color signal corresponding to a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data, and an adjacent to the photoelectric conversion element. The color signal corresponding to the signal charge accumulated in the photoelectric conversion element that detects the same color as the photoelectric conversion element is added at a predetermined ratio to generate a color signal constituting the one-pixel data.

  In the color image data generation method of the present invention, the signal readout circuit transfers signal charges accumulated in the plurality of photoelectric conversion elements and signal charges generated in the photoelectric conversion films in specific directions on the semiconductor substrate, respectively. A vertical transfer path, a horizontal transfer path for transferring the signal charge transferred from the vertical transfer path in a direction orthogonal to the specific direction, and a color signal corresponding to the signal charge transferred from the horizontal transfer path are output. The color signal generation step includes a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data and the same color as the photoelectric conversion element adjacent to the photoelectric conversion element. By driving the solid-state imaging device so that the signal charges accumulated in the photoelectric conversion element for detecting the light are mixed in the vertical transfer path and the horizontal transfer path, It generates color signals constituting the data.

  According to the present invention, high-quality color image data can be generated in an imaging apparatus including a hybrid solid-state imaging device having a photoelectric conversion film in an upper layer portion and a photoelectric conversion element made of silicon in a lower layer portion. it can.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram of the surface of a solid-state image sensor 100 for explaining the first embodiment of the present invention. 2 is a schematic cross-sectional view taken along the line II of FIG.
On the surface portion of the semiconductor substrate 1, a plurality of photoelectric conversion elements 2, 4 and a plurality of signal charge storage portions 3 made of silicon are arranged in the row direction (X direction in FIG. 1) and the column direction (Y direction in FIG. 1). It is arranged. In the present embodiment, the total number of photoelectric conversion elements 2 and photoelectric conversion elements 4 is equal to the number of signal charge storage units 3. The number of signal charge storage units 3 is equal to the maximum number of pixel data of color image data that can be generated based on the color signal obtained from the solid-state imaging device 100.

  As shown in FIG. 1, in an odd-numbered row, a photoelectric conversion element (photodiode, hereinafter referred to as an R photoelectric conversion element) 2 that detects red (R) and generates and accumulates a red signal charge corresponding to the red (R) , Photoelectric conversion elements (photodiodes, hereinafter referred to as B photoelectric conversion elements) 4 that detect blue (B) and generate and store blue signal charges corresponding thereto are alternately arranged in even rows. A signal charge storage section 3 (storage diode) that stores green signal charges is arranged. In the odd-numbered rows, rows where arrangement starts from the R photoelectric conversion elements 2 and rows where arrangement starts from the B photoelectric conversion elements 4 are alternately arranged in the column direction. The odd-numbered rows and the even-numbered rows are arranged so as to be shifted in the row direction by about ½ of the arrangement pitch in the row direction.

  A photoelectric conversion film 19 (see FIG. 2) that detects green light and generates a green signal charge corresponding to the green light is stacked above the surface of the semiconductor substrate 1. The pixel electrode film 5 provided on the photoelectric conversion film 19 is provided so as to cover the signal charge storage unit 3 and the R photoelectric conversion element 2 or the B photoelectric conversion element 4 adjacent thereto. The photoelectric conversion film 19 includes an organic material.

  A vertical transfer path 6 (vertical CCD) for transferring the signal charges accumulated in the photoelectric conversion elements 2 and 4 and the signal charge accumulation unit 3 in the Y direction is provided on the surface portion of the semiconductor substrate 1. A horizontal transfer path 7 (horizontal CCD) for transferring the signal charge transferred from the vertical transfer path 6 in the X direction and a color signal corresponding to the signal charge transferred from the horizontal transfer path 7 are provided on the lower side of An output unit 8 for outputting is provided. The vertical transfer path 6, the horizontal transfer path 7, and the output unit 8 constitute a signal readout circuit in the scope of claims.

  Two vertical transfer paths 6 are provided between the photoelectric conversion elements 2 and 4 arranged in the X direction and between the signal charge storage units 3 arranged in the X direction. Are formed so as to meander between the signal charge storage portion columns and extend in the Y direction.

  By adopting such a configuration, the vertical transfer paths 6 adjacent in the X direction can be adjacent between the photoelectric conversion elements or the signal charge storage units. Therefore, the vertical transfer paths are connected to this portion. Wiring can be provided. Therefore, the signal charge transfer capacity of the vertical transfer path 6 can be increased as compared with a configuration like an interline CCD, and the amount of signal charge stored in the photoelectric conversion elements 2 and 4 and the signal charge storage unit 3 is increased. Can also cope with.

  The configuration of the vertical transfer path 6 shown in FIG. 1 is described in detail in Japanese Patent Laid-Open No. 10-136391, so please refer to this.

  The signal charges accumulated in the R photoelectric conversion element 2, the signal charge accumulation unit 3, and the B photoelectric conversion element 4 are read out to the vertical transfer path 6 from the read gate 20 (shown schematically by arrows in FIG. 1). Then, after being transferred to the horizontal transfer path 7 and then transferred to the output unit 8 by the horizontal transfer path 7, color signals (red signal, green signal, blue signal) corresponding to each signal charge are output from the output unit 8. The In this way, a red signal, a green signal, and a blue signal are read from the solid-state imaging device 100.

  Each readout gate 20 of the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the signal charge storage unit 3 is disposed on the left side of each of the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the signal charge storage unit 3. Provided on the vertical transfer path 6 side. That is, the vertical transfer path 6 disposed on the left side of the signal charge storage unit 3 is a dedicated transfer path for transferring only the green signal charge, and the vertical transfer path disposed on the left side of the photoelectric conversion elements 2 and 4. 6 is a dedicated transfer path for transferring only red and blue signal charges.

  As shown in FIG. 2, a p-well layer 11 is formed on the surface portion of the n-type semiconductor substrate 1, an n-region 4 is formed in the blue (B) pixel region on the surface portion of the p-well layer 11, and the p-well A photodiode as the B photoelectric conversion element 4 is formed between the layer 11 and the n region 4, and the generated signal charge is accumulated in the n region 4.

  In the illustrated example, an n region 3 is formed on the surface portion of the p-well layer 11 between the two n regions 4, and this n region 3 becomes the green signal charge storage unit 3. An n region 6 is provided on the right side of each of the n regions 3 and 4 so as to be slightly separated from each other, and each n region 6 constitutes the vertical transfer path 6 shown in FIG. A transfer electrode that also serves as the readout electrode 12 reaching the n regions 3 and 4 is formed on the surface portion of the n region 6, and a light shielding film 13 is provided on each transfer electrode. The portion of the p-well layer 11 that overlaps the read electrode 12 corresponds to the read gate 20 in FIG.

  A p + region 14 is provided on the left side surface portion and the surface portion of each of the n regions 3 and 4 so as to be separated from the adjacent vertical transfer path 6 and to reduce the defect level of the surface portion. A silicon oxide film (not shown) is formed on the outermost surface of the semiconductor substrate 1, and the transfer electrode 12 is formed thereon.

  A color filter 15 that transmits blue is provided above the opening position of the light shielding film 13 above the n region 4. The color filter 15, the light shielding film 13, and the transfer electrode 12 are embedded in a transparent insulating layer 17.

  The transparent pixel electrode film 5 described with reference to FIG. 1 is formed on the surface of the insulating layer 17, and each pixel electrode film 5 and the n region 3 are connected by a vertical wiring 18. The vertical wiring 18 is electrically insulated from other than the pixel electrode film 5 and the n region 3 to be connected. A photoelectric conversion film 19 over the entire surface of the semiconductor substrate 1 is laminated on each pixel electrode film 5, and a common transparent counter electrode film 20 is formed thereon. The pixel electrode film 5 determines a photoelectric conversion region in the photoelectric conversion film 19, and a region of the photoelectric conversion film 19 sandwiched between the counter electrode film 20 and the pixel electrode film 5 becomes a photoelectric conversion region. The signal charge accumulating unit 3 accumulates signal charges generated in the photoelectric conversion region.

  2 shows a cross section of a portion including the B photoelectric conversion element 4 and the signal charge storage unit 3. However, a cross section of a portion including the R photoelectric conversion element 2 and the signal charge storage unit 3 is illustrated in FIG. Since the configuration is the same except that the n region 4 becomes the n region 2 and the color filter 15 becomes a red color filter that transmits red, the description thereof is omitted.

  When light is incident on the solid-state imaging device 100 having such a configuration, light in the green wavelength region of the incident light is absorbed by the photoelectric conversion film 19 and a green signal charge is generated in the photoelectric conversion film 19. By applying a bias potential to the pixel electrode film 5, the signal charge flows into the n region 3 through the vertical wiring 18 and is accumulated therein.

  Of the incident light, light in the red (R) and blue (B) wavelength regions passes through the photoelectric conversion film 19, and the red light passes through the red color filter and enters the n region 2. As a result, signal charges corresponding to the amount of red light are generated and accumulated in the n region 2. Similarly, the blue light passes through the color filter 15 and enters the n region 4, and signal charges corresponding to the amount of blue light are accumulated in the n region 4.

  The red, green, and blue signal charges accumulated in each of the n regions 2, 3, and 4 are read out to the vertical transfer path 6 when a high potential is applied to the readout electrode 12, and transferred from here to the horizontal transfer path 7. Then, after being transferred to the output unit 8 in the horizontal transfer path 7, a color signal corresponding to each signal charge is output from the output unit 8.

  As described above, according to the solid-state imaging device 100 of the present embodiment, the charge transfer capacity of the vertical transfer path 6 can be made larger than that of the interline CCD. In the solid-state imaging device 100 configured as shown in FIG. 2, adopting a vertical transfer path having a large charge transfer capacity as a signal readout circuit increases the area of the pixel electrode film 5 and the size of the photoelectric conversion element. It is possible to generate higher quality color image data.

  Further, according to the solid-state imaging device 100 of the present embodiment, the signal readout method of the existing CCD image sensor can be applied as it is, and the manufacturing cost can be reduced.

  In addition, according to the solid-state imaging device 100 of the present embodiment, as the semiconductor substrate 1, the semiconductor substrate 1 is manufactured by using the design of an existing single-plate color CCD image sensor or CMOS image sensor as it is. In this case, the vertical wiring 18 is formed instead of the green color filter that needs to be provided in the above, and the pixel electrode film 5, the photoelectric conversion film 19, and the counter electrode film 20 are formed on the upper layer portion. Can be reduced.

  In the solid-state imaging device 100 of the present embodiment, as shown in FIG. 3, a microlens 50 is mounted on the counter electrode film 20, and the incident light of red and blue is shielded from light in the n regions 2 and 4, respectively. It is preferable to condense inside the 13 openings. Further, as shown in FIG. 4, a micro lens 60 is mounted between the color filter 15 and the red color filter and the pixel electrode film 5 so that the incident light of red and blue is opened in the light shielding film 13 in each of the n regions 2 and 4. It is preferable to condense inside.

  The arrangement of the R photoelectric conversion element 2, the B photoelectric conversion element 4, the signal charge storage unit 3, the size and shape of the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the pixel electrode film 5 are shown in FIG. The configuration shown in FIGS. 5 and 6 is not limited to the above. 5 and 6, the same components as those in FIG. 1 are denoted by the same reference numerals.

  The configuration shown in FIG. 5 is such that the R photoelectric conversion element 2 and the B photoelectric conversion element 4 and the pixel electrode film 5 do not overlap. In such a configuration, since the pixel electrode film 5 and the photoelectric conversion elements 2 and 4 do not overlap, the pixel electrode film 5 can be formed of a non-transparent metal such as aluminum or tungsten. There is an advantage that manufacture becomes easy. Further, the configuration as shown in FIG. 5 has an advantage that the signal processing is easy because the position of the center of gravity of the green signal completely coincides with the position of the signal charge storage unit 3.

  In the present embodiment, the semiconductor substrate of the solid-state image sensor 100 is provided with two types of photoelectric conversion elements, ie, a photoelectric conversion element that detects red and a photoelectric conversion element that detects blue, but the present invention is not limited thereto. Instead, a configuration in which two or more types of photoelectric conversion elements are provided may be used.

  In this embodiment, the signal readout circuit is constituted by a charge transfer path as in the CCD type image sensor. However, a signal readout MOS transistor is formed beside each of the n regions 2, 3, and 4, and the conventional CMOS is used. Similarly to the type image sensor, it is also possible to read the color signal from each of the n regions 2, 3, and 4.

  As shown in FIG. 2, in the solid-state imaging device 100, the aperture ratio of the R photoelectric conversion element 2 and the B photoelectric conversion element 4 provided in the lower layer portion is higher than the aperture ratio of the photoelectric conversion film 19 provided in the upper layer portion. Much lower. In addition, when a certain amount of incident light is incident on the solid-state imaging device 100, the amount of light incident on the R photoelectric conversion element 2 and the B photoelectric conversion element 4 provided in the lower layer is the color filter, the light shielding film 13, The amount of light incident on the photoelectric conversion film 19 is smaller due to the influence of the wiring 18 and the aperture ratio. For this reason, the sensitivity of the color signal obtained in the upper layer part and the sensitivity of the color signal obtained in the lower layer part may vary, or the S / N (signal to noise ratio) of the color signal obtained in the lower layer part may deteriorate. Thus, when color image data is generated using color signals obtained from the solid-state imaging device 100, the quality of the image data is degraded. Hereinafter, an imaging apparatus capable of preventing the sensitivity variation and the S / N deterioration will be described.

  An image pickup apparatus for explaining a first embodiment of the present invention is capable of shooting a subject and generating color image data, and is a digital camera, for example.

FIG. 7 is a diagram showing a schematic configuration of a digital camera for explaining the first embodiment of the present invention.
The digital camera shown in FIG. 7 includes an imaging unit 31, an analog signal processing unit 32, an A / D conversion unit 33, a drive unit 34, a strobe 35, and a digital signal processing unit 36. A compression / decompression processing unit 37, a display unit 38, a system control unit 39, an internal memory 40, a media interface 41, a recording medium 42, and an operation unit 43. The digital signal processing unit 36, compression / decompression processing unit 37, display unit 38, system control unit 39, internal memory 40, and media interface 41 are connected to a system bus 44.

  The imaging unit 31 captures a subject with an optical system such as a photographic lens and the solid-state imaging device 100 shown in FIG. 1, and outputs analog color signals (red signal, blue signal, and green signal). The analog signal processing unit 32 performs predetermined analog signal processing on the color signal obtained by the imaging unit 31. The A / D converter 33 digitally converts the analog color signal processed by the analog signal processor 32.

  At the time of shooting, the optical system and the solid-state image sensor 100 are controlled via the drive unit 34. The solid-state imaging device 100 has a timing generator (included in the drive unit 34) at a predetermined timing when a release switch (not shown) is turned on by operating a release button (not shown) that is a part of the operation unit 43. The analog color signal corresponding to the signal charge that is driven by the drive signal from the TG) and is stored in the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the signal charge storage unit 3 is an analog signal processing unit. 32. In the present embodiment, the color signal is read from the solid-state image sensor 100 by interlaced readout that reads the odd-numbered and even-numbered rows of the solid-state image sensor 100 in two times. Progressive readout can also be employed. The drive unit 34 outputs a predetermined drive signal by the system control unit 39.

  The digital signal processing unit 36 performs digital signal processing according to the operation mode set by the operation unit 43 on the digital color signal from the A / D conversion unit 33. The processing performed by the digital signal processing unit 36 includes black level correction processing (OB processing), linear matrix correction processing, white balance adjustment processing, gamma correction processing, color image data generation processing, Y / C conversion processing, and the like. . The digital signal processing unit 36 is configured by a DSP, for example.

  The compression / decompression processing unit 37 performs compression processing on the Y / C data obtained by the digital signal processing unit 36 and also performs decompression processing on the compressed image data obtained from the recording medium 42.

  The display unit 38 includes, for example, an LCD display device, and displays a color image based on color image data that has been photographed and has undergone digital signal processing. An image is also displayed based on image data obtained by decompressing the compressed image data recorded on the recording medium 42. It is also possible to display a through image at the time of shooting, various states of the digital camera, information on operations, and the like.

  The internal memory 40 is, for example, a DRAM and is used as a work memory for the digital signal processing unit 36 and the system control unit 39, and also a buffer memory and a display unit for temporarily storing photographed image data recorded on the recording medium 42 38 is also used as a buffer memory for display image data to 38. The media interface 41 inputs and outputs data with a recording medium 42 such as a memory card.

  The system control unit 39 is mainly configured by a processor that operates according to a predetermined program, and controls the entire digital camera including a shooting operation.

  The operation unit 43 performs various operations when using the digital camera.

  The digital camera shown in FIG. 7 uses the green signal obtained from the upper layer part of the solid-state imaging device 100 as it is for the green signal constituting one pixel data of the color image data, and the red constituting the one pixel data of the color image data. As for the signal and the blue signal, the color signal data is generated by generating the red signal and the blue signal corresponding to the number of pixels of the color image data using the red signal and the blue signal obtained from the lower layer. That is, the digital camera of the present embodiment outputs only a solid-state imaging device that outputs only the number of green signals equal to the number of pixels of color image data, and only the number of red signals and blue signals equal to the number of pixels of color image data. The same processing as that of a digital camera that generates color image data using two solid-state imaging devices is used, and color processing is performed in the same manner as a digital camera having a known two-plate or three-plate CCD image sensor. Generate image data.

The operation of the digital camera shown in FIG. 7 will be described below.
When the release switch is turned on, the solid-state imaging device 100 is driven by the drive unit 34, and the subject is imaged by the solid-state imaging device 100. First, a red signal and a blue signal corresponding to the signal charges accumulated in the R photoelectric conversion element 2 and the B photoelectric conversion element 4 are output from the solid-state imaging device 100 to the analog signal processing unit 32, and then the signal charge accumulation unit 3. A green signal corresponding to the signal charge accumulated in the signal is output from the solid-state imaging device 100 to the analog signal processing unit 32. The red signal, the blue signal, and the green signal are input to the digital signal processing unit 36 through the analog signal processing unit 32 and the A / D conversion unit 33.

  The digital signal processing unit 36 maps the input red signal, blue signal, and green signal on the internal memory 40 in association with the arrangement of the n regions 2, 3, and 4 from which the respective color signals are obtained.

  In the following, color signals obtained from nine photoelectric conversion elements 3 in 3 columns centering on photoelectric conversion elements 2 or 4 corresponding to one pixel data of color image data and one pixel data of color image data The color image data generation processing by the digital signal processing unit 36 will be described using the color signals obtained from the nine signal charge storage units 3 in 3 rows and 3 columns centering on the signal charge storage unit 3 to be processed.

  FIG. 8 is a diagram illustrating color signals mapped to the internal memory 40. FIG. 8A shows mapping of color signals (indicated by “G” in the figure) obtained from nine signal charge storage units 3 centering on the signal charge storage unit 3 corresponding to one pixel data of color image data. FIG. 8B shows a color signal (red signal in the figure) obtained from nine photoelectric conversion elements centering on the R photoelectric conversion element 2 corresponding to one pixel data of the color image data. FIG. 7 is a diagram illustrating a state in which “R” is indicated, and a blue signal is indicated by “B”). In the configuration shown in FIG. 1, the barycentric position of the green signal is actually the center position of the pixel electrode film 5, but in this embodiment, the barycentric position of the green signal is the position of the signal charge storage unit 3. .

  In FIG. 8, in each color signal, a point corresponding to one pixel data of the color image data is defined as a sample point, and symbols a to i are attached to the sample points.

  The digital signal processing unit 36 performs processing for generating one pixel data by giving each sample point shown in FIG. 8 signals of three colors, a red signal, a blue signal, and a green signal.

  Hereinafter, signal processing when generating color image data at each sample point will be described.

  At each sample point, a green signal is present. For this green signal, a sufficient signal amount is obtained as described above, and the S / N is also good. The green signal at each sample point is directly used as a green signal constituting one pixel data (see FIG. 9A).

  Since the red signal and the blue signal are color signals corresponding to the signal charges accumulated in the R photoelectric conversion element 2 and the B photoelectric conversion element 4, as described above, the signal amount is small and the S / N is not good.

  Therefore, the digital signal processing unit 36 obtains a red signal at the sample point and a red signal at the sample point adjacent to the sample point (a signal at the sample point is obtained for a sample point with the red signal. A signal from a photoelectric conversion element that detects the same color as the photoelectric conversion element arranged adjacent to the photoelectric conversion element), and a red signal that constitutes one pixel data at a sample point of the red signal Generate (see FIG. 9B).

  For example, a signal obtained by multiplying each red signal at the sample point a and the adjacent sample points f to i by a predetermined coefficient and multiplying each coefficient by the coefficient is obtained as a sample point a. The red signal constituting one pixel data in FIG. This coefficient can be an arbitrary numerical value such as 1/5 (see FIG. 10A), 1 or the like.

  When the coefficient is 1/5, the signal amount of the red signal at the newly generated sample point a is almost the same as the signal amount of the red signal obtained from one R photoelectric conversion element 2, and the sensitivity of the red signal is increased. I can't do that, but the S / N can be improved accordingly. On the other hand, when the coefficient is 1, the signal amount of the red signal at the newly generated sample point a can be five times the signal amount of the red signal obtained from one R photoelectric conversion element 2. However, the S / N deteriorates accordingly.

  Similarly, with respect to the blue signal, the digital signal processing unit 36 also has a blue signal at the sample point and a blue signal at the sample point adjacent to the sample point (at the sample point). Signal from a photoelectric conversion element that detects the same color as the photoelectric conversion element arranged adjacent to the photoelectric conversion element from which the signal was obtained), and one pixel data at a sample point with a blue signal A blue signal is generated.

  Next, the digital signal processing unit 36 performs a process of interpolating the red signal or blue signal constituting one pixel data at a sample point where the red signal or blue signal constituting one pixel data does not exist. Various known methods can be used for this interpolation. For example, when a blue signal is interpolated at the sample point a, each blue signal after multiplying each blue signal at the sample points b to e around the sample point a by a predetermined coefficient is multiplied by the coefficient. A signal obtained by integrating the signals is a blue signal constituting one pixel data at the sample point a. This coefficient can be an arbitrary numerical value such as 1/4 (see FIG. 10B), 1 or the like.

  In this way, the digital signal processing unit 36 performs processing for giving each sample point a red signal, a blue signal, and a green signal that constitute one pixel data.

  In the generation of the red and blue signals constituting the color image data, it is possible to determine whether to give priority to sensitivity or to give priority to S / N according to the operation mode of the digital camera. For example, when the shooting ISO sensitivity is set high or when shooting in a scene where the amount of light is insufficient, color image data with increased sensitivity is generated by setting the above coefficient to 1, or the shooting ISO sensitivity is low. In the case of setting or when shooting in a scene with too much light, color image data with a good S / N may be generated by setting the coefficient to 1/4 or 1/5.

  When the coordinates on the map of the sample points are (m, n) with the sample point a as the origin, the red signal, blue signal and green signal constituting one pixel data are generated at the sample point where the red signal exists. The above process at the time is expressed by the following formula.

  In the following expression, k (m, n) is a coefficient set at the sample point of coordinates (m, n), and g (m, n) is a process for generating one pixel data at the sample point of coordinates (m, n). The previous green signal (green signal obtained from the signal charge accumulating unit 3 corresponding to one pixel data), b (m, n) is the blue color before generation processing of one pixel data at the sample point of coordinates (m, n) The signal (blue signal obtained from the B photoelectric conversion element 4 corresponding to one pixel data), r (m, n) is a red signal (1 before the pixel data generation processing at the sample point of coordinates (m, n)) Red signal obtained from the R photoelectric conversion element 2 corresponding to pixel data), G (m, n) is a green signal after generation processing of one pixel data at a sample point of coordinates (m, n), B (m, n) n) is a process for generating one pixel data at a sample point of coordinates (m, n). Blue signal after, R (m, n) is the red signal after generation processing of one pixel data at the sample point coordinates (m, n).

G (m, n) = g (m, n)
B (m, n) = k (m, n + 1) * b (m, n + 1) + k (m-1, n) * b (m-1, n) + k (m + 1, n) * b (m + 1, n) + K (m, n-1) * b (m, n-1)
R (m, n) = k (m-1, n + 1) * r (m-1, n + 1) + k (m + 1, n + 1) * r (m + 1, n + 1) + k (m, n) * r (m, n) + K (m-1, n-1) * r (m-1, n-1) + k (m + 1, n-1) * r (m + 1, n-1)
However, b (m, n) is a newly generated blue signal after the addition process.

  On the other hand, the above processing when generating a red signal, a blue signal, and a green signal constituting one pixel data at a sample point where a blue signal exists is expressed as follows.

G (m, n) = g (m, n)
B (m, n) = k (m-1, n + 1) * b (m-1, n + 1) + k (m + 1, n + 1) * b (m + 1, n + 1) + k (m, n) * b (m, n) + K (m-1, n-1) * b (m-1, n-1) + k (m + 1, n-1) * b (m + 1, n-1)
R (m, n) = k (m, n + 1) * r (m, n + 1) + k (m-1, n) * r (m-1, n) + k (m + 1, n) * r (m + 1, n) + K (m, n-1) * r (m, n-1)
However, r (m, n) is a newly generated red signal after the addition process.

  As described above, according to the digital camera of the present embodiment, when the color image data is generated by photographing the subject, the sensitivity of the red signal and the blue signal constituting each pixel data of the color image data is increased, or Since the S / N can be improved, high-quality color image data can be generated.

  In the above description, the color image data is generated by the digital signal processing unit 36. However, the processing performed by the digital signal processing unit 36 may be performed by the analog signal processing unit 32. In this case, the analog signal processing unit 32 uses the analog red signal, blue signal, and green signal input from the imaging unit 31 to perform the same processing as that performed by the digital signal processing unit 36 to generate an analog color signal. Image data may be generated. Further, the analog signal processing unit 32 can perform addition processing between red signals and addition processing between blue signals using a low-pass filter.

  In the above description, it is possible to generate color image data of high quality by performing signal processing on the color signal output from the imaging unit 31, but control the color signal readout method instead of signal processing. It is possible to obtain the same effect.

  In this case, when the drive unit 34 performs drive control to read out the color signal from the solid-state imaging device 100, the signal charge accumulated in the photoelectric conversion element corresponding to one pixel data and the photoelectric conversion element are adjacent to each other. The solid-state imaging device 100 may be driven so that signal charges accumulated in the photoelectric conversion elements that detect the same color as the arranged photoelectric conversion elements are mixed in the vertical transfer path 6 and the horizontal transfer path 7. .

For example, when the photoelectric conversion element corresponding to one pixel data is the second R photoelectric conversion element 2 from the left in the third row of the solid-state imaging device 100 illustrated in FIG. The signal charges accumulated and the four signal charges accumulated in each of the four R photoelectric conversion elements 2 arranged adjacent to the R photoelectric conversion element 2 are mixed in the vertical transfer path 6 and the horizontal transfer path 7. The timing of the drive pulse is controlled as described above.
Similarly, for the B photoelectric conversion element 4, the drive unit 34 also includes signal charges accumulated in the B photoelectric conversion element 4 and four B photoelectric conversion elements 4 arranged adjacent to the B photoelectric conversion element 4. The timing of the drive pulse is controlled so that the four signal charges accumulated in each of the signal charges are mixed in the vertical transfer path 6 and the horizontal transfer path 7.

  The digital signal processing unit 36 may perform signal interpolation processing using the red signal and the blue signal obtained from the solid-state image sensor 100 and generate color image data together with the green signal obtained from the solid-state image sensor 100. .

  In this case, the number of red signals and blue signals obtained from the solid-state imaging device 100 is reduced to 1/5, and the resolution is reduced. However, the coefficient used in the processing performed by the digital signal processing unit 36 is set to 1. The same effect can be obtained. Therefore, high-sensitivity red signals, blue signals, and green signals can be extracted from the solid-state imaging device 100, and high-quality color image data can be generated.

  In the above description, the arrangement of the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the signal charge accumulation unit 3 of the solid-state imaging device 100 is shown in FIG. It can also be arranged as shown in. In FIG. 11, components having the same functions as those in FIG. 11 is the same as the cross section shown in FIG. 2 in which the n region 4 on the left side is the n region 2 and the color filter 15 is a red color filter.

  In the solid-state imaging device shown in FIG. 11, the R photoelectric conversion element 2, the B photoelectric conversion element 4, and the signal charge storage unit 3 are arranged in a square lattice pattern on the semiconductor substrate 1, and the R photoelectric conversion element 2 and the B photoelectric conversion element are arranged. The conversion element 4 and the signal charge storage unit 3 are arranged in a checkered pattern. The vertical transfer path 6 is not meandering and extends in the Y direction linearly along each column.

  In the solid-state imaging device shown in FIG. 11, for example, when the color signal obtained from the R photoelectric conversion device 2, the B photoelectric conversion device 4, and the signal charge storage unit 3 is mapped on the internal memory as shown in FIG. The processing unit 36 adds the color signal of the sample point and the color signal of the same color of the point adjacent to the sample point at a predetermined ratio for the sample points with hatched lines in FIG. A color signal with good sensitivity or S / N is generated. Then, the generated red signal, blue signal and green signal are respectively used to perform synchronization processing and signal interpolation processing by a known method so that each sample point has three color signals of R, G and B. Thus, color image data is generated. According to the configuration of FIG. 11, high-quality color image data can be generated, and high resolution can be realized by signal interpolation.

  Further, the signal processing and charge mixing processing for generating color image data described in the present embodiment can be applied to the solid-state imaging device 200 having the configuration shown in FIG.

  FIG. 13 is a schematic cross-sectional view showing another configuration example of the solid-state imaging device of the present embodiment. FIG. 13 shows only a portion corresponding to one pixel data of the color image data, but actually, the solid-state imaging devices of FIG. 13 are two-dimensionally arranged on the same plane.

  In the solid-state imaging device 200 shown in FIG. 13, an N-type semiconductor layer 67, a P-type semiconductor layer 68, and an N-type semiconductor layer 69 are stacked in this order from the surface of a P-type semiconductor substrate (for example, a silicon substrate) 70 to the inside thereof. It has a structured. A MOS transistor 62 is connected to the N-type semiconductor layer 67, and a MOS transistor 64 is connected to the N-type semiconductor layer 69. The P-type semiconductor substrate 70 and the P-type semiconductor layer 68 are each maintained at the bias potential Vb.

  Above the P-type semiconductor substrate 70, the photoelectric conversion film 19 sandwiched between the pixel electrode film 5 and the counter electrode film 20, like the upper layer part of the solid-state imaging device 100 shown in FIG. Are stacked. The counter electrode film 20 is maintained at the bias potential Vb, and a MOS transistor 63 is connected to the pixel electrode film 5.

  The MOS transistors 62, 63, 64 are connected to a common reset MOS transistor 61 and a common amplification MOS transistor 65, respectively, and a signal selection MOS transistor 66 is connected to the MOS transistor 65. ing. Each MOS transistor and the solid-state imaging device 200 are connected by a signal line. The MOS transistors 61 to 66 and the signal lines connecting them to the solid-state imaging device 200 constitute a signal readout circuit 60. The signal readout circuit 60 is formed on the P-type semiconductor substrate 70, and reads out color signals by the XY address method.

  The depth of the junction of the PN junction between the N-type semiconductor layer 67 and the P-type semiconductor layer 68 from the surface of the P-type semiconductor substrate 70 is a depth that absorbs blue light. Therefore, the PN junction between the N-type semiconductor layer 67 and the P-type semiconductor layer 68 has a photodiode 72 (B) that detects blue light and accumulates signal charges corresponding thereto between the two regions. A photoelectric conversion element 72) is formed.

  The depth of the junction of the PN junction between the N-type semiconductor layer 69 and the P-type semiconductor substrate 70 from the surface of the P-type semiconductor substrate 70 is a depth that absorbs red light. Therefore, the PN junction between the N-type semiconductor layer 69 and the P-type semiconductor substrate 70 detects the red light between these two regions and accumulates the signal charge corresponding thereto. A photoelectric conversion element 73) is formed.

  When signal charges are accumulated in the photoelectric conversion film 19, the B photoelectric conversion element 72, and the R photoelectric conversion element 73, when a bias potential is applied to the pixel electrode film 5, the N-type semiconductor layer 67, and the N-type semiconductor layer 69, photoelectric conversion is performed. Since a potential difference occurs between both ends of the film 19, both ends of the B photoelectric conversion element 72, and both ends of the R photoelectric conversion element 73, this potential difference is read by the signal readout circuit 60, and the photoelectric conversion film 19, B photoelectric conversion element 72, R A color signal corresponding to the signal charge accumulated in each of the photoelectric conversion elements 73 is output from the solid-state imaging element 200.

  In the digital camera shown in FIG. 7, when the solid-state image sensor 200 is used instead of the solid-state image sensor 100, all red signals, blue signals, and green signals are obtained from the same position of the solid-state image sensor 200 corresponding to each sample point. Can do. For this reason, color image data can be generated by the same method as a three-plate color CMOS image sensor. For the red signal and the blue signal, signal processing as described above (processing for adding the color signal at the sample point and the color signal of the same color adjacent to the sample point at a predetermined ratio) or charge mixing processing ( A process of mixing the signal charge accumulated in the photoelectric conversion element corresponding to one pixel data and the signal charge accumulated in the photoelectric conversion element for detecting the same color arranged adjacent to the photoelectric conversion element) By doing so, sensitivity can be increased or S / N can be improved, and high-quality color image data can be generated.

  In addition, since the solid-state imaging device 200 can obtain the red signal, the blue signal, and the green signal from the same position, the synchronization process is unnecessary, and the generation process of the color image data can be simplified.

  The color image sensor having a structure in which a plurality of photoelectric conversion elements are stacked in the depth direction of the semiconductor substrate 70 is described in detail in Japanese Patent Application Publication No. 2002-513145, so please refer to this.

  Similarly to the solid-state image sensor 100, the solid-state image sensor 200 also emits light to the light receiving regions of the R photoelectric conversion element 72 and the B photoelectric conversion element 73 above the counter electrode film 20 or between the semiconductor substrate 70 and the pixel electrode film 5. It is preferable to provide a microlens that collects light.

  In addition, the solid-state imaging device 200 has a configuration in which two types of photoelectric conversion elements, that is, a photoelectric conversion element that detects red color and a photoelectric conversion element that detects blue color are provided on a semiconductor substrate. The photoelectric conversion element may be provided.

  In this embodiment, the photoelectric conversion film provided in the upper layer part of the solid-state image sensor is a photoelectric conversion film that detects green, and the photoelectric conversion element provided in the lower part is a photoelectric conversion element that detects red and blue. Not limited to. In order to realize the present invention, the color detected by the photoelectric conversion film provided in the upper layer portion may be different from the color detected by the photoelectric conversion element provided in the lower layer portion. For example, a photoelectric conversion film that detects red is provided in the upper layer part, a photoelectric conversion element that detects blue and green is provided in the lower part, or a photoelectric conversion film that detects blue is provided in the upper part, and a red color is provided in the lower part. It is also possible to provide a photoelectric conversion element that detects green and green. Since green has a higher human visibility than other colors, the upper layer photoelectric conversion film, which can take the largest light receiving area, detects the green color, making it a color image that is close to the human sense. Data can be generated.

(Second embodiment)
As shown in FIG. 1, solid-state imaging is performed such that the total number of pixel data of color image data is output for the green signal, but the total number of pixel data of color image data is not output for the red and blue signals. In the case of an element, since a process of interpolating a red signal and a blue signal is performed, a false color may occur. In the present embodiment, signal processing capable of suppressing the occurrence of this false color will be described. This signal processing is executed by the digital signal processing unit 36 or the analog signal processing unit 32 shown in FIG.

  In the following, color signals obtained from nine photoelectric conversion elements 3 in 3 columns centering on photoelectric conversion elements 2 or 4 corresponding to one pixel data of color image data and one pixel data of color image data A signal processing method will be described using the color signals obtained from the nine signal charge storage units 3 in 3 rows and 3 columns centering on the signal charge storage unit 3 to be processed.

  FIG. 14 is a diagram illustrating color signals mapped to the internal memory 40. FIG. 14A shows mapping of color signals (indicated by “G” in the figure) obtained from nine signal charge storage units 3 centering on the signal charge storage unit 3 corresponding to one pixel data of color image data. FIG. 14B shows a color signal obtained from nine photoelectric conversion elements centered on the photoelectric conversion element 4 corresponding to one pixel data of the color image data (red signal in the figure). It is a figure which shows the state which mapped "R" and a blue signal are shown by "B".

  In FIG. 14, sample points of each color signal are denoted by symbols a to i. In FIG. 14, the coordinates of the sample point a are the origin (m, n), and the coefficient set at the coordinates (m, n) is k (m, n). Also, the green signal at coordinates (m, n) is g (m, n), the red signal at coordinates (m, n) is r (m, n), and the blue signal at coordinates (m, n) is b. (M, n).

  Hereinafter, signal processing when generating color image data at each sample point will be described.

FIG. 15 is a flowchart for explaining signal processing performed by the digital signal processing unit of the digital camera of this embodiment.
The digital signal processing unit 36 acquires a green signal (first color signal), a red signal (second color signal), and a blue signal (third color signal) from the solid-state imaging device 100 (S1). A green signal at the same sample point as the sample points a to i is subtracted from the red or blue signal of the sample points a to i, and a color signal x (fourth difference) between each of the sample points is the difference between the red signal and the green signal. Color signal) and a color signal y (fourth color signal) which is the difference between the blue signal and the green signal are generated (see S2, FIG. 16). If the color signal x at the coordinates (m, n) is x (m, n) and the color signal y at the coordinates (m, n) is y (m, n), x (m, n) and y (m , N) is obtained by the following equations (1) and (2).

x (m, n) = r (m, n) -g (m, n) (1)
y (m, n) = b (m, n) -g (m, n) (2)

  Next, the digital signal processing unit 36 performs signal interpolation of the color signal x and the color signal y so that two color signals x and y exist at each sample point (see S3 and FIG. 17). For example, the color signal x is interpolated by using the color signal x around the sample point at the sample point where the color signal x does not exist, or the color signal around the sample point is obtained at the sample point where the color signal y does not exist. The color signal y is interpolated using y. Since there are various methods for signal interpolation, description thereof is omitted here.

  Next, the digital signal processing unit 36 transmits the green signal, the color signal x, or the color signal y at each sample point, and the green signal, the color signal x, or the color signal y at the sample points around each sample point. Are added at a predetermined ratio, and at each sample point, a color signal X (fifth color signal) obtained by blurring the color signal x, a color signal Y (fifth color signal) obtained by blurring the color signal y, and a green signal A color signal G ′ with a blurred image is generated (S4).

For example, the digital signal processing unit 36 multiplies the color signal x at the sample point a and each color signal x at the sample points b to i around the sample point a by a predetermined coefficient, and then the coefficient. A signal obtained by integrating the color signals x is defined as a color signal X at the sample point a (see FIG. 18A).
Also, the color signal y at the sample point a and the color signals y at the sample points b to i around the sample point a are multiplied by a predetermined coefficient, and each color signal y after being multiplied by the coefficient is integrated. The obtained signal is set as the color signal Y of the sample point a (see FIG. 18B).
Also, the green signal at the sample point a and the green signals at the sample points b to i around the sample point a are multiplied by a predetermined coefficient, and the respective green signals after multiplication are multiplied. The obtained signal is a color signal G ′ of the sample point a (see FIG. 18C).

  As a coefficient set to each sample point, for example, a weighted sample point a as shown in FIG. 19A or a coefficient equal to each point as shown in FIG. 19B is used.

  The color signal X (m, n), color signal Y (m, n), and color signal G ′ (m, n) generated at the sample point of coordinates (m, n) are expressed by the following equations (3) and (4). , (5).

  G ′ (m, n) = k (m−1, n + 1) * g (m−1, n + 1) + k (m, n + 1) * g (m, n + 1) + k (m + 1, n + 1) * g (m + 1, n + 1) ) + K (m−1, n) * g (m−1, n) + k (m, n) * g (m, n) + k (m + 1, n) * g (m + 1, n) + k (m−1, n-1) * g (m-1, n-1) + k (m, n-1) * g (m, n-1) + k (m + 1, n-1) * g (m + 1, n-1) ( 3)

  X (m, n) = k (m-1, n + 1) * x (m-1, n + 1) + k (m, n + 1) * x (m, n + 1) + k (m + 1, n + 1) * x (m + 1, n + 1) + K (m-1, n) * x (m-1, n) + k (m, n) * x (m, n) + k (m + 1, n) * x (m + 1, n) + k (m-1, n) −1) * x (m−1, n−1) + k (m, n−1) * x (m, n−1) + k (m + 1, n−1) * x (m + 1, n−1) (4 )

  Y (m, n) = k (m-1, n + 1) * y (m-1, n + 1) + k (m, n + 1) * y (m, n + 1) + k (m + 1, n + 1) * y (m + 1, n + 1) + K (m-1, n) * y (m-1, n) + k (m, n) * y (m, n) + k (m + 1, n) * y (m + 1, n) + k (m-1, n) −1) * y (m−1, n−1) + k (m, n−1) * y (m, n−1) + k (m + 1, n−1) * y (m + 1, n−1) (5 )

  Since the color signal x is originally a signal obtained by subtracting the green signal from the red signal, when the blurred color signal G ′ is added to the blurred color signal X, the blurred red color signal R can be obtained. Similarly, since the color signal y is a signal obtained by subtracting the green signal from the blue signal, when the blurred color signal G ′ is added to the blurred color signal Y, a blurred blue color signal B can be obtained. The digital signal processing unit 36 obtains the blurred color signal R and color signal B by the following equations (6) and (7) (S5).

R (m, n) = X (m, n) + G ′ (m, n) (6)
B (m, n) = Y (m, n) + G ′ (m, n) (7)
Here, R (m, n): blurred color signal R at the sample point of coordinates (m, n), B (m, n): blurred color signal B at the sample point of coordinates (m, n)

  Finally, the digital signal processing unit 36 generates a red color signal R ′ constituting one pixel data and a blue color signal B ′ constituting one pixel data from the blurred color signal R and the blurred color signal B. The green color signal G ″ constituting one pixel data is obtained by the following equations (8) and (9), and the following equation (10) is obtained (S6).

R ′ (m, n) = R (m, n) + {g (m, n) −G ′ (m, n)} = X (m, n) + g (m, n) (8)
B ′ (m, n) = B (m, n) + {g (m, n) −G ′ (m, n)} = Y (m, n) + g (m, n) (9)
G ″ (m, n) = G ′ (m, n) + {g (m, n) −G ′ (m, n)} = g (m, n) (10)
Here, R ′ (m, n): a color signal R ′ generated at the sample point of coordinates (m, n), B ′ (m, n): a color signal generated at the sample point of coordinates (m, n) B ′, G ″ (m, n): a color signal G ″ generated at a sample point of coordinates (m, n)

  The digital signal processing unit 36 generates a red signal R ′, a blue signal B ′, and a green signal G ″ at each sample point by the above signal processing.

  As described above, according to the signal processing of the present embodiment, the color signal R ′ and the color signal B ′ constituting one pixel data are generated using the green signal existing for all the sample points. Therefore, compared with the case where the color signal R ′ and the color signal B ′ are generated using only the red signal or the blue signal at each sample point, the false color can be made inconspicuous.

  In the above description, the color signals R and B are once generated in S5 of FIG. 15. However, the color signals R and B are not generated here, and the green signal is directly applied to the color signal X after S4. It is also possible to generate a color signal R ′ by adding the color signals and add a green signal directly to the color signal Y to generate a color signal B ′.

  Further, in the above description, the color signal X, the color signal Y, and the color signal G ′ are generated at each sample point in S4 of FIG. 15. However, the sample point (red color) where the color signal x exists after the process of S2. (Equivalent to the sample point where the signal exists), the red signal existing at the sample point can be handled as it is as the color signal R ′, so that the color signal X is generated for the sample point. Thereafter, the process of adding the green signal to generate the color signal R ′ may not be performed.

  Similarly, for the sample point where the color signal y exists after the processing of S2 (equivalent to the sample point where the blue signal exists), the blue signal present at the sample point is handled as the color signal B ′ as it is. Therefore, the processing for generating the color signal B ′ by generating the color signal Y and then adding the green signal may not be performed for the sample point.

  Further, in the signal processing of this embodiment, before the processing of S1 in FIG. 15, the signal processing as described in the first embodiment (the red signal or the blue signal at each sample point and the sample points adjacent thereto). And adding a red signal or blue signal at a predetermined ratio to generate a new red signal or blue signal), and using the red signal and blue signal obtained by this signal processing, It is preferable to perform the processing after S1 in FIG. By doing so, it is possible to generate color image data in which false colors are not conspicuous and sensitivity is increased or S / N is improved.

Schematic diagram of the surface of a solid-state imaging device for explaining the first embodiment of the present invention Fig. 1 is a schematic cross-sectional view taken along line II 1 is a schematic cross-sectional view of a state in which a microlens is mounted on a solid-state imaging device for explaining a first embodiment of the present invention. 1 is a schematic cross-sectional view of a state in which a microlens is mounted on a solid-state imaging device for explaining a first embodiment of the present invention. The figure which shows another example of an arrangement | sequence of the photoelectric conversion element of the solid-state image sensor and signal charge storage part for describing 1st embodiment of this invention The figure which shows another example of an arrangement | sequence of the photoelectric conversion element of the solid-state image sensor and signal charge storage part for describing 1st embodiment of this invention The figure which shows schematic structure of the digital camera for describing 1st embodiment of this invention The figure which shows the state which mapped on the memory the color signal obtained from the solid-state image sensor for describing 1st embodiment of this invention The figure for demonstrating color image data generation processing The figure which shows the coefficient used for color image data generation processing The figure which shows another structural example of the solid-state image sensor for demonstrating 1st embodiment of this invention. The figure which shows the state which mapped the color signal obtained from another structural example of the solid-state image sensor for describing 1st embodiment of this invention on memory Schematic sectional view showing another configuration example of the solid-state imaging device for explaining the first embodiment of the present invention The figure which shows the state which mapped on the memory the color signal obtained from the solid-state image sensor for describing 2nd embodiment of this invention The flowchart for demonstrating the signal processing in 2nd embodiment of this invention. The figure for demonstrating the signal processing method in 2nd embodiment of this invention. The figure for demonstrating the signal processing method in 2nd embodiment of this invention. The figure for demonstrating the signal processing method in 2nd embodiment of this invention. The figure which shows an example of the coefficient used with the signal processing method in 2nd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Solid-state image sensor 1 Semiconductor substrate 2 R photoelectric conversion element 3 Signal charge storage part 4 B photoelectric conversion element 5 Pixel electrode film 6 Vertical transfer path 7 Horizontal transfer path 8 Output part 18 Vertical wiring 20 Read gate

Claims (14)

An imaging device that images a subject and generates color image data,
A plurality of photoelectric conversion elements including at least two types of photoelectric conversion elements that are arranged on the semiconductor substrate and that are arranged on the semiconductor substrate and detect a color different from the color detected by the photoelectric conversion film; A solid-state imaging device including a signal readout circuit which is formed on the semiconductor substrate and reads out a color signal corresponding to a signal charge accumulated in the plurality of photoelectric conversion elements and a signal charge generated in the photoelectric conversion film;
Of the plurality of photoelectric conversion elements, signal charges accumulated in the photoelectric conversion elements corresponding to one pixel data of the color image data, and the same color as the photoelectric conversion elements arranged adjacent to the photoelectric conversion elements An image pickup apparatus, comprising: a color signal generation unit configured to generate a color signal constituting the one-pixel data based on a signal charge accumulated in a photoelectric conversion element for detecting the color. The imaging apparatus according to claim 1,
The color signal generation unit detects a color signal corresponding to a signal charge stored in a photoelectric conversion element corresponding to one pixel data of the color image data and the same color as the photoelectric conversion element adjacent to the photoelectric conversion element. An image pickup apparatus that adds a color signal corresponding to a signal charge accumulated in a photoelectric conversion element to be generated at a predetermined ratio to generate a color signal constituting the one-pixel data. The imaging apparatus according to claim 1,
The signal readout circuit includes a vertical transfer path for transferring a signal charge accumulated in the plurality of photoelectric conversion elements and a signal charge generated in the photoelectric conversion film in a specific direction on the semiconductor substrate, and a vertical transfer path from the vertical transfer path, respectively. A horizontal transfer path that transfers the transferred signal charge in a direction orthogonal to the specific direction, and an output unit that outputs a color signal corresponding to the signal charge transferred from the horizontal transfer path,
The color signal generation means is a photoelectric conversion element that detects a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data and the same color as the photoelectric conversion element adjacent to the photoelectric conversion element. An image pickup apparatus that generates a color signal constituting the one-pixel data by driving the solid-state image pickup device so that accumulated signal charges are mixed in the vertical transfer path and the horizontal transfer path. The imaging apparatus according to any one of claims 1 to 3,
The solid-state imaging device includes a signal charge accumulation unit that is provided on the semiconductor substrate and accumulates signal charges generated in the photoelectric conversion film, and the semiconductor substrate includes the at least two types of photoelectric conversion elements alternately. An imaging apparatus in which the arranged rows and the rows in which the signal charge storage units are arranged are arranged in a row direction that is approximately ½ pitch of the arrangement pitch of the photoelectric conversion elements and the signal charge storage units in the row direction. The imaging apparatus according to any one of claims 1 to 3,
The solid-state imaging device includes a signal charge accumulation unit that is provided on the semiconductor substrate and accumulates signal charges generated in the photoelectric conversion film,
The imaging device in which the plurality of photoelectric conversion elements and the signal charge storage unit are arranged in a square lattice shape and are arranged in a checkered pattern. The imaging apparatus according to claim 1 or 2,
The signal read circuit includes a MOS transistor and a signal line connected to the MOS transistor,
The plurality of photoelectric conversion elements are imaging devices in which the at least two types of photoelectric conversion elements stacked in the depth direction of the semiconductor substrate are arranged on the same plane of the semiconductor substrate. The imaging device according to any one of claims 1 to 6,
The solid-state imaging device is an imaging device including a plurality of microlenses for condensing light on each of the plurality of photoelectric conversion elements above the photoelectric conversion film. The imaging device according to any one of claims 1 to 6,
The solid-state imaging device is an imaging device including a plurality of microlenses that collect light on each of the plurality of photoelectric conversion elements between the photoelectric conversion film and the plurality of photoelectric conversion elements. The imaging apparatus according to any one of claims 1 to 8,
The photoelectric conversion film detects green light,
The at least two types of photoelectric conversion elements are imaging devices including a photoelectric conversion element that detects red light and a photoelectric conversion element that detects blue light. The imaging apparatus according to any one of claims 1 to 9,
The photoelectric conversion film is an imaging device including an organic material.   A digital camera that performs imaging using the imaging apparatus according to claim 1. A color image data generation method for generating color image data by imaging a subject,
A plurality of photoelectric conversion elements including at least two types of photoelectric conversion elements that are arranged on the semiconductor substrate and that are arranged on the semiconductor substrate and detect a color different from the color detected by the photoelectric conversion film; A solid-state imaging device including a signal readout circuit that is formed on the semiconductor substrate and that reads out a color signal corresponding to a signal charge accumulated in the plurality of photoelectric conversion elements and a signal charge generated in the photoelectric conversion film; A signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data among a plurality of photoelectric conversion elements and the same color as the photoelectric conversion elements arranged adjacent to the photoelectric conversion element Color image data generation method including a color signal generation step for generating a color signal constituting the one-pixel data based on a signal charge accumulated in a photoelectric conversion element to be detected The color image data generation method according to claim 12,
The color signal generation step detects a color signal corresponding to a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data and the same color as the photoelectric conversion element adjacent to the photoelectric conversion element. A color image data generation method for generating a color signal constituting one pixel data by adding a color signal corresponding to a signal charge accumulated in a photoelectric conversion element to be added at a predetermined ratio. The color image data generation method according to claim 12,
The signal readout circuit includes a vertical transfer path for transferring a signal charge accumulated in the plurality of photoelectric conversion elements and a signal charge generated in the photoelectric conversion film in a specific direction on the semiconductor substrate, and a vertical transfer path from the vertical transfer path, respectively. A horizontal transfer path that transfers the transferred signal charge in a direction orthogonal to the specific direction, and an output unit that outputs a color signal corresponding to the signal charge transferred from the horizontal transfer path,
In the color signal generation step, a signal charge accumulated in a photoelectric conversion element corresponding to one pixel data of the color image data and a photoelectric conversion element that detects the same color as the photoelectric conversion element adjacent to the photoelectric conversion element are detected. Color image data generation method for generating color signals constituting the one-pixel data by driving the solid-state imaging device so that accumulated signal charges are mixed in the vertical transfer path and the horizontal transfer path .

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