JP4626706B2 - Solid-state imaging device, signal processing method for solid-state imaging device, and imaging device - Google Patents

Description

  The present invention relates to a solid-state imaging device, a signal processing method for the solid-state imaging device, and an imaging device.

  In a solid-state imaging device, many proposals have been made so far regarding color coding color filter arrays using a color that is a main component of a luminance signal, for example, white (W), and signal processing for the purpose of increasing sensitivity. (For example, see Patent Document 1). As color coding using white, there are many color coding of white checkered in which white is arranged in a checkered pattern.

  Since the color filter array using white has a higher output voltage than the color filter array of the RGB Bayer array that has been widely used heretofore, the sensitivity of the solid-state imaging device can be increased. Here, the RGB Bayer arrangement is color coding in which green (G; Green) is arranged in a checkered pattern and red (R; Red) and blue (B: Blue) are arranged in a checkered pattern in the remaining part.

  On the other hand, in a solid-state imaging device using an RGB Bayer array color filter array, a luminance signal Y is generated when converting an RGB signal into a YUV signal (Y: luminance signal, U, V: color difference signal). Therefore, an arithmetic process is required. As the calculation process, for example, a calculation of Y = 0.29891 × R + 0.58661 × G + 10.1448 × B is performed. These arithmetic processes are generally performed by a DSP (Digital Signal Processor) provided outside the substrate (sensor chip) of the solid-state imaging device.

JP 2007-287891 A

  As described above, by using the white filter that is the main component of the luminance signal in the color filter array, it is possible to increase the sensitivity of the solid-state imaging device. In addition, in the color filter array using the white filter, the sensitivity can be increased while suppressing a decrease in resolution, that is, without reducing the resolution as much as possible, by devising the color arrangement or signal processing.

Accordingly, the present invention provides a solid-state imaging device having a color filter array having a novel color arrangement that can increase sensitivity without reducing the resolution as much as possible, a signal processing method for the solid-state imaging device, and an imaging device having the solid-state imaging device The purpose is to provide.

In order to achieve the above object, the present invention provides:
Pixels are provided on a pixel array section that is two-dimensionally arranged in a matrix, the first color filter that is the main component of the luminance signal is arranged in a checkered pattern, and the second color filter that is the main component of the luminance signal is In a solid-state imaging device having a color filter portion of a color arrangement arranged in a stripe pattern in units of four pixels in an oblique direction, a vertical direction or a horizontal direction,
In response to the signal corresponding to the color arrangement of the color filter unit output from each pixel of the pixel array unit, the signal of the pixel of the second color filter adjacent to the pixel of the filter of the first color is the first signal. It adopts a configuration that performs processing to add to the signal of the pixel of one color filter.

The first color and second color filters, which are the main components of the luminance signal, have higher sensitivity than other color filters. Therefore, in the color arrangement in which the first color filters are arranged in a checkered pattern and the second color filters are arranged in a stripe pattern in units of four pixels in the diagonal direction, the vertical direction, or the horizontal direction, the pixels of the first color filter The amount of the luminance signal is increased by adding the signal of the pixel of the filter of the second color adjacent to the signal of the pixel of the filter of the first color to be the main component of the luminance signal.

According to the present invention, the signal of the pixel of the second color filter adjacent to the pixel of the filter of the first color is added to the signal of the pixel of the filter of the first color and used as the main component of the luminance signal, Since the luminance signal amount can be increased, the sensitivity can be increased without reducing the resolution as much as possible.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings. The description will be given in the following order.

1. First embodiment (in the case of color conversion processing on a sensor chip)
2. Second embodiment (in the case of color conversion processing outside the sensor chip)
3. Modified example 4. Application example (imaging device)

<1. First Embodiment>
[System configuration]
FIG. 1 is a system configuration diagram showing an outline of the configuration of a solid-state imaging device according to the first embodiment of the present invention, for example, a CMOS image sensor which is a kind of XY address type solid-state imaging device.

  The CMOS image sensor 10 </ b> A according to the present embodiment includes a pixel array unit 12 formed on a semiconductor substrate (hereinafter sometimes simply referred to as “sensor chip”) 11, and the same semiconductor substrate 11 as the pixel array unit 12. And a peripheral circuit portion integrated thereon. As the peripheral circuit unit, for example, a vertical driving unit 13, a column processing unit 14, a horizontal driving unit 15, a conversion processing unit 16, and a system control unit 18 are provided.

  In the pixel array unit 12, unit pixels (not shown) including a photoelectric conversion element that photoelectrically converts incident visible light into a charge amount corresponding to the amount of light (hereinafter sometimes simply referred to as “pixel”) are arranged in a matrix. Are two-dimensionally arranged. A specific circuit configuration of the unit pixel will be described later. A color filter array 30 is provided on the light receiving surface (light incident surface) side of the pixel array unit 12. In this embodiment, the color coding of the color filter array 30 is one of the features, and details thereof will be described later.

  The pixel array unit 12 is further provided with a pixel drive line 18 for each row of the matrix-like pixel arrangement along the horizontal direction (pixel arrangement direction / horizontal direction of the pixel row) for each row, and a vertical signal for each column. A line 19 is formed along the vertical direction (pixel array direction / vertical direction of the pixel column) in the figure. In FIG. 1, one pixel drive line 18 is shown, but the number is not limited to one. One end of the pixel drive line 18 is connected to an output end corresponding to each row of the vertical drive unit 13.

  The vertical drive unit 13 includes a shift register, an address decoder, and the like. Here, although the illustration of a specific configuration is omitted, the vertical drive unit 13 has a configuration including a readout scanning system and a sweep scanning system. The readout scanning system sequentially performs selective scanning in units of rows for unit pixels from which signals are read out.

  On the other hand, the sweep-out scanning system removes unnecessary charges from the photoelectric conversion elements of the unit pixels of the readout row preceding the readout scan by the time of the shutter speed with respect to the readout row where the readout scanning is performed by the readout scanning system. Sweep out (reset) sweep scanning. A so-called electronic shutter operation is performed by sweeping (reset) unnecessary charges by the sweep scanning system. Here, the electronic shutter operation refers to an operation in which the photoelectric charge of the photoelectric conversion element is discarded and a new exposure is started (photocharge accumulation is started).

  The signal read by the reading operation by the reading scanning system corresponds to the amount of light incident after the immediately preceding reading operation or electronic shutter operation. The period from the read timing by the previous read operation or the sweep timing by the electronic shutter operation to the read timing by the current read operation is the photocharge accumulation time (exposure time) in the unit pixel.

  A signal output from each unit pixel of the pixel row selectively scanned by the vertical driving unit 13 is supplied to the column processing unit 14 through each of the vertical signal lines 19. The column processing unit 14 performs predetermined signal processing on the analog pixel signal output from each pixel in the selected row for each pixel column of the pixel array unit 12.

  Examples of signal processing in the column processing unit 14 include CDS (Correlated Double Sampling) processing. In the CDS process, a reset level and a signal level output from each pixel in a selected row are captured, and a signal of pixels for one row is obtained by taking a difference between these levels, and a fixed pattern noise of the pixel is removed. It is. The column processing unit 14 may be provided with an A / D conversion function for digitizing an analog pixel signal.

  The horizontal driving unit 15 includes a shift register, an address decoder, and the like, and selectively scans circuit portions corresponding to the pixel columns of the column processing unit 14 in order. By the selective scanning by the horizontal driving unit 15, pixel signals that are signal-processed for each pixel column by the column processing unit 14 are sequentially output.

  The conversion processing unit 16 converts the signal corresponding to the color array of the color filter array (color filter unit) 30 output from the pixel array unit 12 via the column processing unit 14 into a Bayer array by arithmetic processing. Performs conversion to the corresponding signal. In the present embodiment, the conversion processing unit 16 is provided on the same substrate as the pixel array unit 12, that is, the sensor chip 11, and color conversion processing is performed on the sensor chip 11 to output a signal corresponding to the Bayer array outside the sensor chip 11. Another feature is the point of output to. Details of specific conversion processing in the conversion processing unit 16 will be described later in detail.

  Here, as is well known, the Bayer array is two types of color information components in which colors that are the main components of a luminance signal that requires high resolution are arranged in a checkered pattern, and the remaining portions do not require a relatively high resolution. A color arrangement in which the colors of are arranged in a checkered pattern. As a basic form of the Bayer arrangement, color coding of a color arrangement in which green (G), which has a large contribution ratio of the luminance signal, is arranged in a checkered pattern and R (red) / B (blue) is arranged in a checkered pattern in the remaining part. Is mentioned.

  The system control unit 17 receives a clock given from the outside of the sensor chip 11, data for instructing an operation mode, and the like, and outputs data such as internal information of the CMOS image sensor 10. The system control unit 17 further includes a timing generator that generates various timing signals, and based on the various timing signals generated by the timing generator, the vertical driving unit 13, the column processing unit 14, the horizontal driving unit 14, and the like. Drive control of the conversion processing unit 16 and the like is performed.

(Circuit configuration of unit pixel)
FIG. 2 is a circuit diagram illustrating an example of a circuit configuration of the unit pixel 20. As shown in FIG. 2, the unit pixel 20 according to this circuit example includes a photoelectric conversion element, for example, a photodiode 21, and four transistors, for example, a transfer transistor 22, a reset transistor 23, an amplification transistor 24, and a selection transistor 25. It has a configuration.

  Here, as the four transistors 22 to 25, for example, N-channel MOS transistors are used. However, the conductivity type combinations of the transfer transistor 22, the reset transistor 23, the amplification transistor 24, and the selection transistor 25 illustrated here are merely examples, and are not limited to these combinations.

  For the unit pixel 20, as the pixel drive line 18, for example, three drive wirings of a transfer line 181, a reset line 182 and a selection line 183 are provided in common for each pixel in the same pixel row. One end of each of the transfer line 181, the reset line 182, and the selection line 183 is connected to the output end corresponding to each pixel row of the vertical drive unit 13 in units of pixel rows.

  The photodiode 21 has an anode electrode connected to a negative power source (for example, ground), and photoelectrically converts received light into photocharge (here, photoelectrons) having a charge amount corresponding to the light amount. The cathode electrode of the photodiode 21 is electrically connected to the gate electrode of the amplification transistor 24 through the transfer transistor 22. A node 26 electrically connected to the gate electrode of the amplification transistor 24 is referred to as an FD (floating diffusion) portion.

  The transfer transistor 22 is connected between the cathode electrode of the photodiode 21 and the FD portion 26. A transfer pulse φTRF in which the high level (for example, Vdd level) is active (hereinafter referred to as “High active”) is applied to the gate electrode of the transfer transistor 22 via the transfer line 181. When the transfer pulse φTRF is applied, the transfer transistor 22 is turned on and the photoelectric charge photoelectrically converted by the photodiode 21 is transferred to the FD unit 26.

  The reset transistor 23 has a drain electrode connected to the pixel power source Vdd and a source electrode connected to the FD unit 26. A high active reset pulse φRST is applied to the gate electrode of the reset transistor 23 via the reset line 182 prior to the transfer of the signal charge from the photodiode 21 to the FD unit 26. When the reset pulse φRST is given, the reset transistor 23 is turned on, and the FD unit 26 is reset by discarding the charge of the FD unit 26 to the pixel power supply Vdd.

  The amplification transistor 24 has a gate electrode connected to the FD unit 26 and a drain electrode connected to the pixel power source Vdd. Then, the amplification transistor 24 outputs the potential of the FD unit 26 after being reset by the reset transistor 23 as a reset signal (reset level) Vreset. The amplification transistor 24 further outputs the potential of the FD unit 26 after the transfer of the signal charge by the transfer transistor 22 as a light accumulation signal (signal level) Vsig.

  For example, the selection transistor 25 has a drain electrode connected to the source electrode of the amplification transistor 24 and a source electrode connected to the vertical signal line 17. A high active selection pulse φSEL is applied to the gate electrode of the selection transistor 25 via a selection line 163. When the selection pulse φSEL is given, the selection transistor 25 is turned on, the unit pixel 20 is selected, and the signal output from the amplification transistor 24 is relayed to the vertical signal line 17.

  Note that the selection transistor 25 may have a circuit configuration connected between the pixel power supply Vdd and the drain of the amplification transistor 24.

  In addition, the unit pixel 20 is not limited to the pixel configuration including the four transistors having the above configuration. For example, a pixel configuration including three transistors that serve as both the amplification transistor 24 and the selection transistor 25 may be used, and the configuration of the pixel circuit is not limited.

  By the way, in general, pixel addition is performed to add and read signals from a plurality of adjacent pixels in order to increase the frame rate when capturing a moving image. This can be performed in the pixel, on the signal line, in the column processing unit 14, or in the subsequent signal processing unit. Here, as an example, a pixel configuration in the case where signals of four pixels adjacent vertically and horizontally are added within the pixel will be described.

  FIG. 3 is a circuit diagram showing an example of a circuit configuration in the case where adjacent four-pixel addition is performed within a pixel. In FIG. 3, the same parts as those in FIG.

  In FIG. 3, the four-pixel photodiodes 21 that are adjacent vertically and horizontally are referred to as photodiodes 21-1, 21-2, 21-3, and 21-4. For these photodiodes 21-1, 21-2, 21-3, 21-4, four transfer transistors 22-1, 22-2, 22-3, 22-4 are provided, and reset transistors 23, One amplification transistor 24 and one selection transistor 25 are provided.

  That is, each of the transfer transistors 22-1, 22-2, 22-3, and 22-4 has one electrode connected to each cathode electrode of the photodiodes 21-1, 21-2, 21-3, and 21-4. The other electrode is connected in common to the gate electrode of the amplification transistor 24. A common FD section 26 is electrically connected to the photodiodes 21-1, 21-2, 21-3, and 21-4 at the gate electrode of the amplification transistor 24. The reset transistor 23 has a drain electrode connected to the pixel power source Vdd and a source electrode connected to the FD unit 26.

  In the pixel configuration corresponding to the addition of adjacent four pixels in the above configuration, the transfer pulses φTRF are applied to the four transfer transistors 22-1, 22-2, 22-3, and 22-4 at the same timing so as to be adjacent to each other. Pixel addition between four pixels can be realized. That is, the signal charges transferred from the photodiodes 21-1, 21-2, 21-3, 21-4 to the FD unit 26 by the transfer transistors 22-1, 22-2, 22-3, 22-4 are The FD unit 26 adds the values.

On the other hand, by supplying the transfer pulse φTRF to the transfer transistors 22-1, 22-2, 22-3, and 22-4 at different timings, signal output in units of pixels can be realized. That is, the frame rate can be improved by performing pixel addition at the time of moving image capturing, whereas the resolution can be improved by reading the signals of all the pixels independently at the time of still image capturing.

[Color coding of color filter array]
Next, color coding of the color filter array 30 as one of the features of the present embodiment will be described.

  In the color filter array 30 according to the present embodiment, the first color filters that are the main components of the luminance signal are arranged in a checkered pattern, and the second color filters that are the main components of the luminance signal are oblique, vertical, or horizontal. The color arrangement is arranged in stripes in units of four pixels in the direction. Here, as a filter of the first color and the second color which are the main components of the luminance signal, a W / G filter may be mentioned.

  Each W / G filter, which is a main component of the luminance signal, has higher sensitivity than other colors (specifically, R / B filters). In particular, the W filter has a sensitivity as high as about twice that of the G filter. Therefore, the sensitivity (S / N) can be improved by arranging the W / G filters, particularly the W filters, in a checkered pattern. However, since the W filter includes various types of color information, so-called color falsification that reproduces a color different from the original color of the subject is likely to occur. Conversely, the G filter is less sensitive than the W filter, but is less likely to produce color falsification. That is, sensitivity and color falsity are in a trade-off relationship.

  When the W filter is arranged in a checkered pattern as the main component of the luminance signal, the multiple color filters that are color information components arranged in the remaining portion are R / G / B filters. On the other hand, when the G filters are arranged in a checkered pattern as the main component of the luminance signal, the multiple color filters that are color information components arranged in the remaining portions are R / B filters.

  Thus, by using the color filter array 30 that is color-coded in which the W filter is arranged in a checkered pattern as the color that is the main component of the luminance signal, the sensitivity of the W filter is higher than that of other colors. Since it is high, the sensitivity of the CMOS image sensor 10 can be increased. On the other hand, since the color filter array 30 uses a color coding array in which the G filter is arranged in a checkered pattern as the main component of the luminance signal, the G filter is less prone to color falsification than the W filter. The color reproducibility of the CMOS image sensor 10 can be improved.

  In the CMOS image sensor 10 </ b> A according to the present embodiment, signals corresponding to these color arrays are converted into signals corresponding to the Bayer array on the sensor chip 11 when any color coding color filter array 30 is used. Try to convert. At this time, since the colors that are the main components of the luminance signal are arranged in a checkered pattern, the signals of the other main colors can be restored using the color signals that are the main components. The conversion efficiency of the color conversion in the unit 16 can be increased.

  Further, by outputting a signal corresponding to the Bayer array from the sensor chip 11, an existing DSP for the Bayer array can be used as a signal processing unit at the subsequent stage. The DSP for the Bayer array performs a process of generating the luminance signal Y and the two color difference signals U (B−Y) and V (R−Y) based on the signal corresponding to the Bayer array output from the sensor chip 11. Basic processing.

As described above, since the existing DSP for the Bayer array can be used, even if the color coding of the color filter array 30 is changed, it is not necessary to newly develop a DSP that requires enormous development costs. As a result, the cost of the camera module including the DSP can be reduced, and in particular, the color filter array 30 for color coding using the W filter can be contributed.

[Specific example of color coding of color filter array]
Next, a specific example of color coding that facilitates conversion from a signal corresponding to a color array in which color filters, which are main components of a luminance signal, are arranged in a checkered pattern to a signal corresponding to an RGB Bayer array will be described.

(First example)
FIG. 4 is a color arrangement diagram showing color coding according to the first specific example. As shown in FIG. 4, in the color coding according to the first specific example, the W filters are arranged in a checkered pattern, the R / B filters are arranged in a checkered pattern with two vertical and horizontal pixel pitches, and between the R / B filters. Is one pixel shift, and the rest is a G filter.

  Specifically, the W filters are arranged in a checkered pattern when the vertical 4 pixels and the horizontal 4 pixels are used as a unit. The R filter is arranged in the first column of the second row and the third column of the fourth row, and the B filter is arranged in the second column of the first row and the fourth column of the third row. This arrangement is a checkered arrangement with a vertical and horizontal two-pixel pitch. Then, G filters are arranged at the remaining pixel positions. At this time, the G filter has an oblique stripe arrangement.

(Second specific example)
FIG. 5 is a color arrangement diagram showing color coding according to the second specific example. As shown in FIG. 5, in the color coding according to the second specific example, the W filters are arranged in a checkered pattern, the R / B filters are arranged in a square with a vertical and horizontal pixel pitch of 4 pixels, and the R / B filters are interleaved. Are arranged in units of two pixels in an oblique direction, and the rest is a G filter.

  Specifically, the W filters are arranged in a checkered pattern when the vertical 4 pixels and the horizontal 4 pixels are used as a unit. The R filter is arranged in the fourth column of the third row and the third column of the fourth row, and the B filter is arranged in the second column of the first row and the first column of the second row. This arrangement is a square arrangement with a vertical and horizontal 4-pixel pitch. Then, G filters are arranged at the remaining pixel positions. At this time, the G filter has an oblique stripe arrangement.

  Each of the color codings according to the first and second specific examples described above has a color arrangement in which W filters having the highest output level are arranged in a checkered pattern as color filters that are the main components of the luminance signal. Since the W filter is arranged in a checkered pattern, the W filter includes R / G / B color components, so that the conversion accuracy into a signal corresponding to the RGB Bayer array can be improved.

  In these color codings, when a W filter pixel is replaced with a G filter in a color conversion process described later, each R / B filter matches a part of the position of each R / B filter in the Bayer array. It has the feature. For missing portions that do not match, it can be said that the conversion efficiency is very good because the information of each pixel of R / B can be restored by using the information of the pixel of the W filter.

  In addition, the color codings according to the first and second specific examples are characterized in that the W filters are arranged in a checkered pattern, and a part of the G filter is arranged in a stripe pattern in an oblique direction in units of four pixels. It is said. In this color coding, the luminance signal amount can be increased by adding the signal of the G filter pixel adjacent to the pixel of the W filter to the signal of the pixel of the W filter to be the main component of the luminance signal. The sensitivity (S / N) can be improved. In particular, in the case of color coding according to the first specific example, the R / B filters are arranged in a checkered pattern with two vertical and horizontal pixel pitches, and the R / B filters are shifted one pixel diagonally. The conversion efficiency into signals corresponding to the Bayer array can be increased.

In both color codings according to the first and second specific examples, the G filters are arranged in stripes in units of four pixels in an oblique direction. Therefore, in the case of these color codings, in the color conversion processing described later, the G pixel signal adjacent to the W pixel is added to the signal of the W pixel and used as the main component of the luminance signal. Higher sensitivity (higher S / N) can be realized while suppressing the decrease. This effect is not limited to the case where the G filters are arranged in stripes in units of 4 pixels in the oblique direction, but the same applies to cases where the G filters are arranged in stripes in units of 4 pixels in the vertical or horizontal direction. I can say.

[Sensitivity ratio of W: G: R: B]
Here, the sensitivity ratio of W: G: R: B will be described. In color coding including a W filter, pixels of the W filter having a high output signal level are saturated earlier than pixels of other color filters. Therefore, by reducing the sensitivity of the pixels of the W filter and relatively increasing the sensitivity of the pixels of the other color filters, the sensitivity of each W: G: R: B pixel is balanced, that is, W: G: It is necessary to adjust the sensitivity ratio of each pixel of R: B.

  A known exposure control technique can be used to adjust the sensitivity ratio. Specifically, there is a technique for balancing the amount of incident light among pixels of each color by adjusting the size of an on-chip microlens provided in units of pixels outside the color filter array 30 (for example, Japanese Patent Laid-Open No. Hei 9- 116127). Utilizing this technology, the size of the on-chip microlens of the W pixel is made smaller than that of the other color pixels, thereby reducing the sensitivity of the W filter pixels and relatively increasing the sensitivity of the other color filter pixels. be able to.

  As another exposure control technique, in color coding including a W filter, there is a technique for reducing the sensitivity difference by eliminating the on-chip microlens of the W pixel and at the same time increasing the color sensitivity to improve the color S / N. (For example, refer to JP 2007-287891 A). By utilizing this technique, it is possible to reduce the sensitivity of the pixels of the W filter and relatively increase the sensitivity of the pixels of the other color filters.

  In addition, there is a technique for preventing color balance from being lost by performing shutter exposure control that shortens the exposure time of the G filter pixels as compared to the exposure time of the R / B filter pixels (for example, Japanese Patent Laid-Open 2003-60992 gazette). Combining this shutter exposure control technique with the control of the light receiving area can also reduce the sensitivity of the pixels of the W filter and relatively increase the sensitivity of the pixels of other color filters. The coloring of can be eliminated. As a result, an achromatic process in an external signal processor (DSP) is not necessary.

  The exposure control technique used for adjusting the sensitivity ratio mentioned here is merely an example, and is not limited to the above three examples.

  Here, an example of the size proposal when the size of the former W pixel on-chip microlens is adjusted will be described. The approximate ratio of the output level of each pixel of W / G / B / R is W: G: B: R = 2: 1: 0.5: 0.5.

For the on-chip microlens of W pixel, the area difference is doubled by ± 0.1 μm sizing with 1.1 μm pixel, so the output level of W pixel is equal to G pixel at the same size with double sensitivity difference Can be completely corrected to the same level. Even if the size is 1.1 μm and ± 0.05 μm sizing, the area difference is 1.42 times, so the sensitivity difference can be reduced to 1.42 times. At this time, the remaining difference (sensitivity difference) may be corrected together with the shutter exposure control.

[Color conversion processing]
Next, details of a process (color conversion process) for converting into a signal corresponding to the RGB Bayer array by the color conversion process by the conversion processing unit 16 will be described.

  Regarding color conversion processing, color conversion processing at the time of still image imaging (at the time of full scanning) that scans all pixels and color conversion processing at the time of video imaging (at the time of pixel addition) that adds the signals of a plurality of adjacent pixels Divided. As described above, the color coding according to the first specific example and the second specific example is a color conversion process that can realize high sensitivity, and can adopt a low illumination mode. The conversion process can be divided into two color conversion processes.

  One of the two color conversion processes is a color conversion process at a time of high luminance in which the incident light luminance is higher than a predetermined reference luminance, and this is referred to as color conversion processing 1. The other is color conversion processing at low luminance below the reference luminance, which is referred to as color conversion processing 2. Also, the color conversion process at the time of pixel addition can be divided into a plurality of color conversion processes depending on the difference in the combination of pixels to be added.

(In the case of color coding according to the first specific example)
First, color conversion processing in the case of color coding according to the first specific example will be described. First, the color conversion process 1 at the time of high brightness at the time of full scan will be described using the flowchart of FIG. 6 and the conceptual diagram of FIG.

  As shown in the flowchart of FIG. 6, the color conversion process 1 at the time of high luminance is basically realized by sequentially executing the processes of step S11, step S12, and step S13. FIG. 7A shows a color arrangement of 4 × 4 pixels of color coding according to the first specific example.

  In step S11, as shown in FIG. 7B, a checkered white (W) pixel component is processed into pixels of all colors by determining the directionality of the resolution. Here, the direction of resolution means the direction in which the pixel signal exists. In FIG. 7B, W indicated by a white square (□) represents a W pixel component developed for each color.

  In developing the W pixel component to all other color pixels, signal processing using a well-known directional correlation can be used. As a signal processing technique using this directional correlation, for example, a plurality of color signals corresponding to a specific pixel are obtained, and the correlation values in the vertical direction and / or the horizontal direction at the position corresponding to the specific pixel are obtained. Examples of the technology to be obtained (for example, see Japanese Patent No. 2931520).

  In step S12, as shown in FIG. 7C, the W pixel is replaced with the G pixel from the correlation between the W pixel and the G pixel. As is clear from the color arrangement of the various color codings described above, the W pixel and the G pixel are adjacent to each other. Looking at the correlation between the W pixel and the G pixel in a certain region, both are colors that are the main components of the luminance signal, and thus have a fairly strong correlation, and the correlation value (correlation coefficient) is close to 1. By determining the directionality of the resolution using this color correlation and changing the output level of the W pixel to a level equivalent to the G pixel, the W pixel can be replaced with the G pixel.

  In step S13, each pixel of the Bayer R / B is generated from the correlation between the W pixel and the R / B pixel, as shown in FIG. Since the W filter includes R / G / B color components, the W pixel and the R / B pixels can be correlated. For this signal processing, a well-known technique (for example, see Japanese Patent Application Laid-Open No. 2005-160044) that interpolates the luminance signal substituted for G in all the pixels in the four color arrangement can be used.

  Next, the color conversion process 2 at the time of low brightness during full scan will be described using the flowchart of FIG. 8 and the conceptual diagram of FIG.

  First, the directionality of the resolution is observed as shown in FIG. 9A by using the signal processing using the well-known directional correlation described above (step S21). Then, it is determined whether or not the directionality can be determined (step S22). If the directionality can be determined, the checkered W pixel components are developed into pixels of all colors (step S23).

  Next, by using the above-described well-known technique, each R / B pixel is generated from the correlation between the W pixel and each R / B pixel as shown in FIG. 9B (step S24). Next, as shown in FIG. 9C, by adding the signal of two G pixels adjacent to the W pixel to the signal of the W pixel and approximating G (= W + 2G), the result shown in FIG. As shown, each pixel of the Bayer R / B is generated (step S25).

  If the directionality cannot be determined in step S22, each pixel of the Bayer R / B is generated by simple four-pixel equal interpolation that complements equally between four pixels that are vertically and horizontally adjacent (step S26).

  As described above, by using the color conversion processing 1 or the color conversion processing 2 according to the luminance of incident light, a signal corresponding to a color array in which W filters are arranged in a checkered pattern is converted into a signal corresponding to an RGB Bayer array. Can be converted and output on the sensor chip 11.

  Next, two color conversion processes at the time of pixel addition during moving image capturing will be described. These two color conversion processes are referred to as pixel addition process 1 and pixel addition process 2.

  First, the pixel addition process 1 will be described with reference to the flowchart of FIG. 10 and the conceptual diagram of FIG.

  First, with respect to the W pixel, addition processing is performed between two pixels positioned in an oblique direction (step S31). Specifically, as shown in FIG. 11A, addition is performed between the pixel of interest and a pixel located diagonally to the lower right of the pixel of interest (a pixel on the right next to one column and one row below). For the addition of the W pixel, in the pixel configuration shown in FIG. 3, the transfer pulse φTRF is simultaneously applied to the transfer transistors 22 of the two pixels to be added, in this example, the transfer transistors 22-1 and 22-4. In the FD unit 26, two-pixel addition can be performed. This pixel addition is called FD addition.

  Next, for each pixel of R / G / B, interlaced addition is performed between two pixels located in an oblique direction opposite to the case of the W pixel (step S32). Specifically, as shown in FIG. 11B, interlaced addition is performed between the pixel of interest and the pixel located diagonally to the left of the pixel of interest (pixels adjacent to the left of two columns and two rows below). As for the addition of each R / G / B pixel, for example, when the column processing unit 14 shown in FIG.

  More specifically, in the color arrangement shown in FIG. 12, the signals of the B1 and G1 pixels are read out independently, and the signals of the B2 and G3 pixels are read out continuously after A / D conversion of these signals. Two-pixel addition can be performed by performing A / D conversion. As a technique for performing pixel addition at the time of A / D conversion in the column processing unit 14, a known technique for converting an analog pixel signal into a digital pixel signal using a counter (for example, JP-A-2006-033454) Reference) can be used.

  A process of performing pixel addition using a counter that constitutes a part of the A / D conversion unit is referred to as counter addition. If the gain is changed for each line when performing this counter addition, the addition ratio can be made variable. Counter addition can be performed in the same manner for the R pixel. Incidentally, in the above-described two-pixel addition for the W pixel, FD addition is performed between the pixels W1 and W2 and between the pixels W3 and W4.

  Next, as shown in FIG. 11C, the W pixel component is fitted to each R / G / B pixel (step S33). Next, as shown in FIG. 11D, four pixels of the RGB Bayer array are generated (step S34).

  Next, the pixel addition process 2 will be described using the flowchart of FIG. 13 and the conceptual diagram of FIG.

  First, for the W pixel and the G pixel, W / R / G / B is generated by performing FD addition between two pixels located in the left-right diagonal direction (step S41). Specifically, for the W pixel, as shown in FIG. 14A, between the pixel of interest and a pixel located diagonally below and to the right of the pixel of interest (pixel adjacent to the right of one column and one row below) FD addition is performed. As for the G pixel, as shown in FIG. 14B, FD addition is performed between the pixel of interest and a pixel located diagonally to the lower left of the pixel of interest (pixel adjacent to the left of one column and one row below).

  Here, in a total of 8 pixels of 4 vertical pixels × 4 horizontal pixels, one set of R / B signals is not used. That is, thinning readout without pixel addition is performed for each R / B pixel. Accordingly, since the sensitivity of R / B is lower than that in the case of the pixel addition processing 1, the color S / N is poor.

  Next, as shown in FIG. 14C, the W pixel component is fitted to each R / G / B pixel (step S42). Next, as shown in FIG. 14D, four pixels of the RGB Bayer array are generated (step S43). In the pixel addition process 2, the center of gravity of the RGB Bayer array is slightly shifted from that in the pixel addition process 1.

  As described above, by using the pixel addition processing 1 or the pixel addition processing 2 at the time of moving image capturing, a signal corresponding to a color array in which W filters are arranged in a checkered pattern is converted into a signal corresponding to an RGB Bayer array. It can be converted and output above.

(In the case of color coding according to the second specific example)
Next, color conversion processing in the case of color coding according to the second specific example will be described. The flow of a series of color coding processes according to the second specific example is basically based on the color coding according to the first specific example.

  First, the color conversion process 1 at the time of full scan will be described with reference to the conceptual diagram of FIG. In the color arrangement of 4 × 4 pixels of color coding according to the second specific example shown in FIG. 15A, looking at the directionality of the resolution, as shown in FIG. Expands to all color pixels. Next, from the correlation between the W pixel and the G pixel, the W pixel is replaced with the G pixel as shown in FIG. Then, from the correlation between the W pixel and the R / B pixels, the Bayer R / B pixels shown in FIG. 15D are generated.

  Next, color conversion processing 2 at the time of full scan will be described using the conceptual diagram of FIG. As in the case of the color conversion process 1, in the color arrangement of 4 × 4 pixels of color coding according to the second specific example, the directionality of the resolution is seen, and as shown in FIG. Are expanded to pixels of all colors. Next, from the correlation between the W pixel and each R / B pixel, each R / B pixel is generated as shown in FIG. Then, as shown in FIG. 16C, two G pixel signals adjacent to the W pixel are added to the W pixel signal to approximate G (= W + 2G), as shown in FIG. , Each pixel of the Bayer R / B is generated. At this time, if there is directionality, the addition ratio may be changed to active.

  Subsequently, the pixel addition process 1 will be described with reference to FIG. As shown in FIGS. 17A and 17B, W / R / G / B pixels are generated by performing left-right diagonal FD addition on the W pixels and R / G / B pixels. Then, as shown in FIG. 17C, the W pixel component is fitted to each pixel to generate four pixels in the RGB Bayer array shown in FIG.

  Next, the pixel addition process 2 will be described with reference to FIG. As shown in FIGS. 18A and 18B, W / R / G / B pixels are generated by performing left-right diagonal FD addition on the W pixels and R / G / B pixels. Then, as shown in FIG. 18C, the W pixel component is fitted to each R / B pixel to generate four pixels in the RGB Bayer array shown in FIG.

As described above, in the color coding according to the first and second specific examples of the color arrangement in which the W filters that are the main components of the luminance signal are arranged in a checkered pattern and the G filters are arranged in stripes in the diagonal direction, The following effects can be obtained by performing signal processing. That is, in the conversion processing unit 16 on the sensor chip 11, the luminance signal amount can be increased by performing signal processing using the signal of the G pixel adjacent to the W pixel as a main component of the luminance signal by adding the signal of the W pixel to the signal of the W pixel. . As a result, the sensitivity can be increased without reducing the resolution as much as possible.

<2. Second Embodiment>
[System configuration]
FIG. 19 is a system configuration diagram showing an outline of a configuration of a solid-state imaging device according to the second embodiment of the present invention, for example, a CMOS image sensor which is a kind of XY address type solid-state imaging device. Equivalent parts are indicated by the same reference numerals.

  In the CMOS image sensor 10A according to the first embodiment described above, the conversion processing unit 16 provided in the sensor chip 11 converts a signal corresponding to the color array of the color filter array 30 into a signal corresponding to the RGB Bayer array. It has a configuration. On the other hand, in the CMOS image sensor 10B according to the present embodiment, W / R / G / B signals corresponding to the color arrangement of the color filter array 30 are directly output from the sensor chip 11 as RAW data (raw data). It is the composition which becomes.

  The CMOS image sensor 10B according to the present embodiment employs a configuration in which color conversion processing is performed on the RAW data output from the sensor chip 11 by the DSP circuit 40 that is an external circuit of the sensor chip 11. The DSP circuit 40 converts the W / R / G / B signal output from the sensor chip 11 into a signal corresponding to the RGB Bayer array, and then performs a known demosaic process. Here, the demosaicing process is a process of creating a full color image by complementing the color information by collecting and giving the missing color information from the signals of the surrounding pixels to the signal of each pixel having only monochrome color information. .

As described above, the CMOS image sensor 10B according to the present embodiment outputs W / R / G / B signals corresponding to the color arrangement of the color filter array 30 to the sensor chip 11 as they are, and the DSP circuit 40 performs RGB Bayer arrangement. It is characterized in that it is converted into a signal corresponding to. Therefore, the configurations and operations of the pixel array unit 12, the vertical drive unit 13, the column processing unit 14, the horizontal drive unit 15 and the system control unit 17 provided on the sensor chip 11 are the same as those in the first embodiment. Yes, and the description is omitted here because it is redundant.

[Color coding of color filter array]
The CMOS image sensor 10B according to the present embodiment is also characterized by the color coding of the color filter array 30 that can be easily converted into a signal corresponding to the RGB Bayer array, as in the case of the CMOS image sensor 10A according to the first embodiment. One of them.

That is, in the color filter array 30, the first color (W / G) filters that are the main components of the luminance signal are arranged in a checkered pattern, and the second color (G / W) filters that are the main components of the luminance signal are arranged. The color arrangement is arranged in stripes in units of four pixels in the oblique direction, the vertical direction, or the horizontal direction. The effect of using the color coding color filter array 30 is the same as in the first embodiment.

[Specific example of color coding of color filter array]
A specific example of color coding that allows easy conversion from a signal corresponding to a color array in which color filters, which are main components of a luminance signal, are arranged in a checkered pattern to a signal corresponding to an RGB Bayer array is also described in the first embodiment. The first and second specific examples are the same as in the case.

In other words, in the color coding according to the first specific example, the W filters are arranged in a checkered pattern, the R / B filters are arranged in a checkered pattern with a vertical and horizontal pixel pitch, and the R / B filters are diagonally shifted by one pixel. The rest is a G filter (see FIG. 4). Further, in the color coding according to the second specific example, the W filters are arranged in a checkered pattern, the R / B filters are arranged in a square with a vertical and horizontal pixel pitch of 2 and the R / B filters are diagonally 2 They are arranged in pixel units, and the rest are G filters (see FIG. 5).

[Color conversion processing]
Next, details of a color conversion process in the DSP circuit 40 for converting a signal corresponding to the color array of the color filter array 30 output as RAW data from the sensor chip 11 into a signal corresponding to the RGB Bayer array will be described.

  In this color conversion process, as in the case of the first embodiment, the sensitivity ratio of each pixel of W: G: R: B is adjusted. As in the case of the first embodiment, the color conversion processing is divided into color conversion processing at the time of full scan and color conversion processing at the time of pixel addition. Further, the processing at the time of full scan is also divided into color conversion processing 1 when the incident light luminance is higher than the predetermined reference luminance and color conversion processing 2 when the luminance is lower than the reference luminance.

(In the case of color coding according to the first specific example)
First, color conversion processing in the case of color coding according to the first specific example will be described. First, the color conversion process 1 at the time of high brightness at the time of full scan will be described using the flowchart of FIG. 20 and the conceptual diagram of FIG.

  A color arrangement of 4 × 4 pixels of color coding according to the first specific example is shown in FIG. In the color coding according to the first specific example, first, by using the signal processing using the well-known directional correlation described above, as shown in FIG. The directionality is judged and developed to pixels of all colors (step S51). Next, by using the above-described well-known technique, each component of R / G / B is converted to all pixels as shown in FIG. 21C from the correlation between the W pixel and each pixel of R / G / B. (Step S52).

  Next, color conversion processing 2 at low luminance during full scan will be described using the flowchart of FIG. 22 and the conceptual diagram of FIG.

  First, the directionality of the resolution is observed as shown in FIG. 23A by using the signal processing using the well-known directional correlation described above (step S61). Then, it is determined whether or not the directionality can be determined (step S62). If the directionality can be determined, the checkered W pixel components are developed into pixels of all colors (step S63).

  Next, by using the above-described well-known technique, as shown in FIG. 23B, each R / B pixel is generated from the correlation between the W pixel and each R / B pixel (step S64). If the directionality cannot be determined in step S62, each pixel of R / B is generated by simple four-pixel equal interpolation that complements equally between four pixels that are adjacent vertically and horizontally (step S66).

  Next, as shown in FIG. 23C, the directionality is determined from the W pixel, and the signal of the two G pixels adjacent to the W pixel is changed to the signal of the W pixel and the ratio is changed to active (W + 2G). ) To generate a checkered array (step S65). Thereafter, the directionality is further determined and developed to all pixels to obtain a luminance signal (step S66).

  As described above, by using the color conversion processing 1 or the color conversion processing 2 according to the luminance of incident light, a signal corresponding to a color array in which W filters are arranged in a checkered pattern is converted into a signal corresponding to an RGB Bayer array. The signal can be converted by the signal processing of the DSP circuit 40 outside the sensor chip 11.

  Next, two color conversion processes 1 and 2 at the time of pixel addition at the time of moving image capturing will be described. First, the pixel addition process 1 will be described with reference to the flowchart of FIG. 24 and the conceptual diagram of FIG.

  First, as shown in FIG. 25A, FD addition is performed between two pixels positioned in the diagonal direction for the W pixel, and counter addition is performed between two pixels positioned in the diagonal direction for the RGB pixel (step S71). Next, from the correlation between the W pixel and each R / G / B pixel, as shown in FIG. 25B, each R / G / B component is developed in all pixels (step S72). Then, as shown in FIG. 25C, the W pixel signal and the G pixel signal are added at a ratio of 1: 2 to obtain W + 2G, and the W + 2G signal is used as a luminance signal (step S73).

  Next, the pixel addition process 2 will be described with reference to the flowchart of FIG. 26 and the conceptual diagram of FIG.

  First, for W and G pixels, as shown in FIG. 27A, W and G are generated by performing FD addition between two pixels located in the diagonal direction (step S81). Specifically, for the G pixel, FD addition is performed between the pixel of interest and a pixel located diagonally to the left of the pixel of interest (a pixel on the left of one column and one row below). For the W pixel, FD addition is performed between the pixel of interest and a pixel located diagonally below and to the right of the pixel of interest (pixel adjacent to the right of one column and one row below). The R and B pixels are left as they are.

  Next, from the correlation between the W pixel and each R / G / B pixel, each component of R / G / B is expanded to all pixels as shown in FIG. 27B (step S82). Then, the W pixel signal and the G pixel signal are added at a ratio of 1: 2 to obtain W + 2G, and the W + 2G signal is set as a luminance signal (step S83).

  As described above, by using the pixel addition process 1 or the pixel addition process 2 at the time of moving image capturing, the signal corresponding to the color array in which the W filter is arranged in a checkered pattern is changed to the signal corresponding to the RGB Bayer array. Conversion can be performed by signal processing of the external DSP circuit 40.

(In the case of color coding according to the second specific example)
Next, color conversion processing in the case of color coding according to the second specific example will be described. The flow of a series of color coding processes according to the second specific example is basically based on the color coding according to the first specific example.

  First, the color conversion process 1 at the time of full scan will be described with reference to the conceptual diagram of FIG. FIG. 28A shows a color arrangement of 4 × 4 pixels of color coding according to the second specific example. In the color coding according to the second specific example, in view of the directionality of the resolution, as shown in FIG. 28B, the checkered W pixel components are developed into pixels of all colors. Next, from the correlation between the W pixel and each R / G / B pixel, each component of R / G / B is expanded to all pixels as shown in FIG.

  Next, color conversion processing 2 at the time of full scan will be described using the conceptual diagram of FIG. As in the case of the color conversion process 1, in the color arrangement of 4 × 4 pixels of color coding according to the second specific example, the directionality of the resolution is seen, and as shown in FIG. Are expanded to pixels of all colors.

  Next, from the correlation between the W pixel and each R / B pixel, each component of R / B is expanded to all pixels as shown in FIG. Then, as shown in FIG. 29C, the directionality is determined from the W pixel, and the signal of the two G pixels adjacent to the W pixel is changed to the signal of the W pixel, and the ratio is changed to active (W + 2G). To create a checkered array. Thereafter, the directionality is judged and developed to all pixels to obtain a luminance signal.

  Subsequently, the pixel addition process 1 will be described with reference to FIG. First, with respect to the W pixel and the G pixel, as shown in FIG. 30A, a signal of each pixel of W, R, G, and B is generated by performing FD addition between two pixels located in the diagonal direction. To do. Next, from the correlation between the W pixel and each R / G / B pixel, each component of R / G / B is expanded to all pixels as shown in FIG. Then, after the component of the W pixel is fitted to each pixel to improve the S / N, an RGB signal is obtained.

  Next, the pixel addition process 2 will be described with reference to FIG. First, with respect to the W pixel and the G pixel, as shown in FIG. 31A, a signal of each pixel of W, R, G, and B is generated by performing FD addition between two pixels located in the diagonal direction. To do. Next, from the correlation between the W pixel and each R / G / B pixel, each component of R / G / B is expanded to all pixels as shown in FIG. Then, the W pixel signal and the G pixel signal are added at a ratio of 1: 2 to obtain W + 2G, and the W + 2G signal is used as a luminance signal.

As described above, in the color coding according to the first and second specific examples of the color arrangement in which the W filters that are the main components of the luminance signal are arranged in a checkered pattern and the G filters are arranged in stripes in the diagonal direction, The following effects can be obtained by performing signal processing. That is, in the DSP circuit 40 outside the sensor chip 11, the amount of luminance signal can be increased by performing signal processing using the signal of the G pixel adjacent to the W pixel as a main component of the luminance signal by adding the signal of the W pixel. As a result, the sensitivity can be increased without reducing the resolution as much as possible.

<3. Modification>
In each of the above-described embodiments, the signal of two G pixels adjacent to the W pixel is simply added to the signal of the W pixel to be a pseudo main component of the luminance signal. The number is not limited to two pixels, and may be one pixel. Incidentally, by using the two-pixel addition for adding the signals of one G pixel adjacent to the W pixel, it is possible to suppress a decrease in resolution as compared with the case of the three-pixel addition for adding the signals of two G pixels.

  Further, in each of the above embodiments, the signal processing in the case where the G filter has a stripe arrangement in units of four pixels in an oblique direction has been described as an example. However, in the vertical direction or in the horizontal direction, stripes are formed in units of four pixels. A similar effect can be obtained even when they are arranged. Furthermore, the addition ratio of the first color filter and the second color filter is not limited to 1: 1, and the resolution and sensitivity may be balanced at an arbitrary addition ratio.

Further, in each of the above embodiments, the case of color coding in which the first color that is the main component of the luminance signal is white (W) and the second color is green (G) is taken as an example, but the first color is green. In the case of color coding in which the second color is white, similar effects can be obtained. In this case, FIG. 32 shows color coding according to the first specific example, and FIG. 33 shows color coding according to the second specific example.

<4. Application example>
[Imaging device]
FIG. 34 is a block diagram showing an example of the configuration of the imaging apparatus according to the present invention.

  As shown in FIG. 34, an imaging apparatus 100 according to the present invention includes an optical system including a lens group 101 and the like, an imaging element 102, a DSP circuit 103 which is a camera signal processing circuit, a frame memory 104, a display apparatus 105, and a recording apparatus 106. The operation system 107 and the power supply system 108 are included. The DSP circuit 103, the frame memory 104, the display device 105, the recording device 106, the operation system 107, and the power supply system 108 are connected to each other via a bus line 109.

  The lens group 101 captures incident light (image light) from a subject and forms an image on the imaging surface of the imaging element 102. The imaging element 102 converts the amount of incident light imaged on the imaging surface by the lens group 101 into an electrical signal in units of pixels and outputs the electrical signal. As the image sensor 102, the CMOS image sensors 10A and 10B according to the first and second embodiments described above are used.

  The CMOS image sensors 10A and 10B have a color coding of a color arrangement in which colors as main components of luminance signals are arranged in a checkered pattern and a plurality of colors as color information components are arranged in the remaining portion as a color filter array. have. In particular, in the case of the CMOS image sensor 10A, a signal corresponding to the color array of the color filter array is converted into a signal corresponding to the Bayer array by arithmetic processing on the sensor chip 11.

  Therefore, the CMOS image sensor 10A outputs a signal corresponding to the Bayer array while the color filter array is color coding in which the main color of the luminance signal is arranged in a checkered pattern. As a result, the DSP circuit 103 has an existing process for generating the luminance signal Y and the two color difference signals U (B−Y) and V (R−Y) based on signals corresponding to the Bayer array. DSPs for Bayer arrays can be used.

  As described above, since the existing Bayer array DSP can be used, even if the color coding of the color filter array used in the image sensor 102 is changed, it is not necessary to newly develop a DSP that requires enormous development costs. . Thereby, it is possible to contribute to the cost reduction of the imaging apparatus 100 including the DSP circuit 103 and the spread of the color coding color filter array using the W filter.

  On the other hand, in the case of the CMOS image sensor 10B, a signal corresponding to a color arrangement in which the main component of the luminance signal is arranged in a checkered pattern is output to the outside of the chip, and the DSP circuit 103 (to the DSP circuit 40 in FIG. 19). Equivalent), the signal is converted into a signal corresponding to the RGB Bayer array. Accordingly, although the development cost is high, it is necessary to newly develop the DSP circuit 103 in order to cope with the change of the color coding of the color filter array. However, in the case of the CMOS image sensor 10B, as in the case of the CMOS image sensor 10A, since the sensitivity can be increased without reducing the resolution as much as possible, the S / N of the imaging signal is improved while maintaining high resolution. There are advantages you can do.

  The display device 105 includes a panel type display device such as a liquid crystal display device or an organic EL (electroluminescence) display device, and displays a moving image or a still image captured by the image sensor 102. The recording device 106 records a moving image or a still image captured by the image sensor 102 on a recording medium such as a video tape or a DVD (Digital Versatile Disk).

The operation system 107 issues operation commands for various functions of the imaging apparatus under operation by the user. The power supply system 108 appropriately supplies various power supplies serving as operation power supplies for the DSP circuit 103, the frame memory 104, the display device 105, the recording device 106, and the operation system 107 to these supply targets.

1 is a system configuration diagram showing an outline of a configuration of a CMOS image sensor according to a first embodiment of the present invention. It is a circuit diagram which shows an example of the circuit structure of a unit pixel. It is a circuit diagram which shows an example of a circuit structure in case adjacent 4 pixel addition is performed within a pixel. It is a color arrangement | sequence diagram which shows the color coding which concerns on a 1st specific example. It is a color arrangement | sequence figure which shows the color coding which concerns on a 2nd specific example. It is a flowchart which shows the flow of an example of the color conversion process 1 at the time of the high brightness | luminance at the time of a full scan in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is a conceptual diagram of the color conversion process 1 at the time of high brightness at the time of full scan in the case of color coding according to the first specific example of the first embodiment. It is a flowchart which shows the flow of an example of the color conversion process 2 at the time of the low brightness at the time of a full scan in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is a conceptual diagram of the color conversion process 2 at the time of low brightness at the time of full scan in the case of color coding according to the first specific example of the first embodiment. It is a flowchart which shows the flow of an example of the pixel addition process 1 in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is a conceptual diagram of the pixel addition process 1 in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is explanatory drawing about FD addition and counter addition. It is a flowchart which shows the flow of an example of the pixel addition process 2 in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is a conceptual diagram of the pixel addition process 2 in the case of the color coding which concerns on the 1st specific example of 1st Embodiment. It is a conceptual diagram of the color conversion process 1 in the case of the color coding which concerns on the 2nd specific example of 1st Embodiment. It is a conceptual diagram of the color conversion process 2 in the case of the color coding which concerns on the 2nd specific example of 1st Embodiment. It is a conceptual diagram of the pixel addition process 1 in the case of the color coding which concerns on the 2nd specific example of 1st Embodiment. It is a conceptual diagram of the pixel addition process 2 in the case of the color coding which concerns on the 2nd specific example of 1st Embodiment. It is a system block diagram which shows the outline of a structure of the CMOS image sensor which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the flow of an example of the color conversion process 1 at the time of the high brightness | luminance at the time of a full scan in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a conceptual diagram of the color conversion process 1 at the time of high brightness at the time of full scan in the case of color coding according to the first specific example of the second embodiment. It is a flowchart which shows the flow of an example of the color conversion process 2 at the time of the low brightness at the time of a full scan in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a conceptual diagram of the color conversion process 2 at the time of low brightness at the time of full scan in the case of color coding according to the first specific example of the second embodiment. It is a flowchart which shows the flow of an example of the pixel addition process 1 in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a conceptual diagram of the pixel addition process 1 in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a flowchart which shows the flow of an example of the pixel addition process 2 in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a conceptual diagram of the pixel addition process 2 in the case of the color coding which concerns on the 1st specific example of 2nd Embodiment. It is a conceptual diagram of the color conversion process 1 in the case of the color coding which concerns on the 2nd specific example of 2nd Embodiment. It is a conceptual diagram of the color conversion process 2 in the case of the color coding which concerns on the 2nd specific example of 2nd Embodiment. It is a conceptual diagram of the pixel addition process 1 in the case of the color coding which concerns on the 2nd specific example of 2nd Embodiment. It is a conceptual diagram of the pixel addition process 2 in the case of the color coding which concerns on the 2nd specific example of 2nd Embodiment. It is a color arrangement | sequence figure which shows the color coding which concerns on the 1st specific example of a modification. It is a color arrangement | sequence diagram which shows the color coding which concerns on the 2nd specific example of a modification. It is a block diagram which shows an example of a structure of the imaging device which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10A, 10B ... CMOS image sensor, 11 ... Semiconductor substrate, 12 ... Pixel array part, 13 ... Vertical drive part, 14 ... Column processing part, 15 ... Horizontal drive part, 16 ... Conversion part, 17 ... System control part, 20 ... Unit pixel, 21 ... photodiode, 22 ... transfer transistor, 23 ... reset transistor, 24 ... amplification transistor, 25 ... select transistor, 26 ... FD (floating diffusion) section, 30 ... color filter array, 40 ... DSP circuit

Claims (12)

Pixels are provided on a pixel array section that is two-dimensionally arranged in a matrix, the first color filter that is the main component of the luminance signal is arranged in a checkered pattern, and the second color filter that is the main component of the luminance signal is A color filter portion having a color arrangement arranged in a stripe shape in units of four pixels in an oblique direction, a vertical direction, or a horizontal direction;
In response to the signal corresponding to the color arrangement of the color filter unit output from each pixel of the pixel array unit, the signal of the pixel of the second color filter adjacent to the pixel of the filter of the first color is the first signal. A solid-state imaging device comprising: a signal processing unit that performs a process of adding to a pixel signal of a filter of one color. The first color filter is a white filter or a green filter;
The solid-state imaging device according to claim 1, wherein the second color filter is a green filter when the first color filter is a white filter, and is a white filter when the first color filter is a green filter. In the color filter section, white filters are arranged in a checkered pattern, red and blue filters are arranged in a checkered pattern with a vertical and horizontal pixel pitch, and the red and blue filters are diagonally shifted by one pixel, and the rest are green filters The solid-state imaging device according to claim 2, wherein the color arrangement is as follows. In the color filter section, white filters are arranged in a checkered pattern, red and blue filters are arranged in a square arrangement with a vertical and horizontal pixel pitch, and the red and blue filters are arranged diagonally in units of two pixels, and the rest The solid-state imaging device according to claim 2, wherein the color arrangement is a green filter. 5. The solid-state imaging device according to claim 3, wherein the signal processing unit adds a signal of one pixel or two pixels of a green filter pixel adjacent to a pixel of the white filter to a signal of the pixel of the white filter. In the color filter section, the green filters are arranged in a checkered pattern, the red and blue filters are arranged in a checkered pattern with a vertical and horizontal pixel pitch, the red and blue filters are diagonally shifted by one pixel, and the rest are white filters The solid-state imaging device according to claim 2, wherein the color arrangement is as follows. In the color filter section, the green filters are arranged in a checkered pattern, the red and blue filters are arranged in a square arrangement with a vertical and horizontal pixel pitch of 4 pixels, and the red and blue filters are arranged diagonally in units of 2 pixels. The solid-state imaging device according to claim 2, wherein the color arrangement becomes a white filter. 8. The solid-state imaging device according to claim 6, wherein the signal processing unit adds a signal of one pixel or two pixels of a pixel of a white filter adjacent to a pixel of the green filter to a signal of a pixel of the green filter. The signal processing unit is provided on the same substrate as the pixel array unit, and converts a signal corresponding to the color array of the color filter unit output from each pixel of the pixel array unit into a signal corresponding to the Bayer array. The solid-state imaging device according to claim 1. The signal processing unit is provided outside the substrate on which the pixel array unit is formed, and a signal corresponding to the color array of the color filter unit output from each pixel of the pixel array unit is converted into a signal corresponding to the Bayer array. The solid-state imaging device according to claim 1, wherein after the conversion, arithmetic processing for converting the luminance signal and the color difference signal is performed. Pixels are provided on a pixel array section that is two-dimensionally arranged in a matrix, the first color filter that is the main component of the luminance signal is arranged in a checkered pattern, and the second color filter that is the main component of the luminance signal is In the signal processing of the solid-state imaging device having the color filter portion of the color arrangement arranged in a stripe shape in units of four pixels in the oblique direction, the vertical direction or the horizontal direction,
In response to the signal corresponding to the color arrangement of the color filter unit output from each pixel of the pixel array unit, the signal of the pixel of the second color filter adjacent to the pixel of the filter of the first color is the first signal. A signal processing method for a solid-state imaging device that performs a process of adding to a pixel signal of a filter of one color. Pixels are provided on a pixel array section that is two-dimensionally arranged in a matrix, the first color filter that is the main component of the luminance signal is arranged in a checkered pattern, and the second color filter that is the main component of the luminance signal is A color filter portion having a color arrangement arranged in a stripe shape in units of four pixels in an oblique direction, a vertical direction, or a horizontal direction;
In response to the signal corresponding to the color arrangement of the color filter unit output from each pixel of the pixel array unit, the signal of the pixel of the second color filter adjacent to the pixel of the filter of the first color is the first signal. An image pickup apparatus comprising: a solid-state image pickup apparatus including: a signal processing unit that performs a process of adding to a pixel signal of a filter of one color.

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