JP2009050030A - Solid-state imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging apparatus capable of imaging a low-illuminance subject with high sensitivity. <P>SOLUTION: A solid-state imaging apparatus includes a plurality of first pixels each including a colorless filter 10 which transmits all wavelength areas of visible light, for converting the visible light into a first electric signal; a plurality of second pixels each including a first filter 200 which has a peak of spectral transmittance in a first wavelength of visible light, for converting light of the first wavelength into a second electric signal; a plurality of third pixels each including a second filter 30 which has a peak of spectral transmittance in a second wavelength different from the first wavelength in visible light, for converting light of the second wavelength into a third electric signal; a pixel region 101 in which the first to third pixels are arrayed in a matrix shape on a semiconductor substrate; and an arithmetic unit 110 which receives the first to third electric signals generated by certain incident light to the pixel region and uses the first to third electric signals to calculate a fourth electric signal corresponding to a third wavelength different from the first wavelength and the second wavelength. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device.

  A CMOS (Complimentary Metal-Oxide Semiconductor) image sensor has been developed as a solid-state imaging device. Along with the reduction of the design rule in the semiconductor process, a single-plate color image sensor having a size of about 2.5 μm square and exceeding 5 megapixels has recently been commercialized. In addition, as a CCD (charge-coupled device), a digital still camera using a single-plate color image sensor composed of pixels having a size of about 1.86 μm square has been commercialized.

  In a single-plate color image sensor, a CFA (Color-Filter-Array) called a Bayer array is formed in a pixel region in order to acquire color image information with one chip. In the Bayer array, two green (G) pixels are diagonally arranged in a pixel block of 2 rows and 2 columns, and red (R) pixels and blue (B) pixels are 1 as the remaining two pixels. It has a configuration in which pixels are arranged. This Bayer array is adopted as the most general CFA array. The green pixel, the red pixel, and the blue pixel are pixels that receive green light, red light, and blue light, respectively, and output an electrical signal based on the light intensity. The reason why the Bayer array is generally adopted as the CFA array is as follows.

  Green (G) is the color that has the greatest influence on human visual sensation in visible light, and the luminance signal Y in the television standard is expressed by Equation 1.

Y = 0.299R + 0.587G + 0.114B (Formula 1)
Here, G represents green light intensity, R represents red light intensity, and B represents blue light intensity. The light intensity is a voltage or current of an electric signal generated by the pixel due to the photoelectric effect when receiving light of a certain intensity. As can be seen with reference to Equation 1, the luminance signal in the television standard is configured so that the contribution of green light is the largest (Patent Document 2).

  Therefore, in the Bayer array, by increasing the ratio of the green pixels and arranging the green pixels in a checkered pattern, it is possible to obtain a higher level luminance signal and at the same time increase the resolution of the luminance signal.

  In addition, Patent Document 1 discloses a CFA array using all RGB pixels and visible light pixels W.

According to the definition of JIS-Z8120, the wavelengths of electromagnetic waves corresponding to visible light are approximately 360 nm to 400 nm on the short wavelength side and 760 nm to 830 nm on the long wavelength side. In general image sensors, visible light in the wavelength range of about 400 nm to 700 nm is imaged.
JP 2004-304706 A JP-A-8-9395

  In a single-plate color image sensor employing a Bayer array CFA, a green pixel includes a filter that transmits a green component of incident light and absorbs a red component and a blue component. When the green transmission filter is used, the peak of the transmittance is reduced to about 80% of the incident light. Therefore, conventionally, the utilization factor of the green component of incident light is 80% at the maximum. The utilization rates of the red component and blue component were about 95% and 80%, respectively.

  On the other hand, the amount of incident light is reduced due to the miniaturization of pixels. This means that in a solid-state imaging device in which pixels are miniaturized, sensitivity in imaging a low-illuminance subject is lowered.

  When a color image is captured, it is necessary to acquire and reproduce three types of color information having different wavelengths from each other in order to reproduce the color information of the subject. However, as described above, the transmittance of the color filter for obtaining the three types of color information is 80 to 95%, and the incident light cannot be sufficiently utilized. As long as a color filter that transmits monochromatic light is used, the light energy of the other two colors is absorbed by the filter and lost. That is, a solid-state imaging device using color filters corresponding to RGB has low sensitivity in imaging a low-illuminance subject.

  Accordingly, an object of the present invention is to provide a solid-state imaging device capable of imaging a low-illuminance subject with high sensitivity.

A solid-state imaging device according to an embodiment of the present invention includes a colorless filter that transmits the entire wavelength range of visible light, and a plurality of first pixels that convert the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit includes a coefficient determined by a spectral transmittance of the first filter and a coefficient determined by a spectral transmittance of the second filter for each of the second electric signal and the third electric signal. And the result obtained by the multiplication is subtracted from the first electric signal, and the fourth electric signal is obtained based on the result obtained by the subtraction.

A solid-state imaging device according to an embodiment of the present invention includes:
A plurality of first pixels including a colorless filter that transmits the entire wavelength range of visible light, and converting the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit includes a coefficient determined by a spectral transmittance of the first filter and a coefficient determined by a spectral transmittance of the second filter for each of the second electric signal and the third electric signal. , The results obtained by this multiplication are added together, the first electrical signal is divided by the result obtained by this addition, 1 is subtracted from the result obtained by this division, and this subtraction The fourth electric signal is obtained by multiplying the first electric signal by the obtained result.

A solid-state imaging device according to an embodiment of the present invention includes:
A plurality of first pixels including a colorless filter that transmits the entire wavelength range of visible light, and converting the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit uses the second and third electrical signals from the second and third pixels adjacent to the first pixel to generate the first wavelength based on the first wavelength in the first pixel. Interpolating two electrical signals and a third electrical signal with the second wavelength;
Using the first and third electrical signals from the first and third pixels adjacent to the second pixel, the first electrical signal by the visible light in the second pixel and the first Interpolating a third electrical signal with a wavelength of 2;
Using the first and second electrical signals from the first and second pixels adjacent to the third pixel, the first electrical signal by the visible light in the third pixel and the second Interpolating a second electrical signal with a wavelength of 1;
The fourth electric signal is calculated using the first to third electric signals after interpolation in each pixel.

A solid-state imaging device according to an embodiment of the present invention includes:
A plurality of first pixels including a colorless filter that transmits the entire wavelength range of visible light, and converting the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals generated by light incident on a pixel region comprising the first to third pixels, and using the first to third electrical signals, 1 to 3 and a calculation unit for generating a luminance signal and a color difference signal of each of the third pixels.

  The solid-state imaging device according to the present invention can image a low-illuminance subject with high sensitivity.

  Embodiments according to the present invention will be described below with reference to the drawings. This embodiment does not limit the present invention.

(First embodiment)
FIG. 1 is a block diagram showing a solid-state imaging device according to the first embodiment. The solid-state imaging device 100 includes a silicon substrate 90, an imaging region 101, a load transistor 102, a correlated double sampling (CDS) circuit 103, a V (Vertical) selection circuit 104, an H (Horizontal) selection circuit 105, an automatic A gain control circuit (AGC (Automatic Gain Controller)) 106, an A / D converter (ADC (Analog-Digital Converter)) 107, a digital amplifier 108, a signal processor (DSP (Digital Signal Processor)) 110, and a timing generator ( TG (Timing Generator) 109 is provided. These elements are formed on one semiconductor chip. The ADC 107 and the CDS circuit 103 may be integrally configured as a column type CDS-ADC circuit.

  The imaging region 101 includes a plurality of pixels that convert incident light into electrical signals by photoelectric conversion. The plurality of pixels are arranged in a two-dimensional matrix. The load transistor 102 is connected between the substrate potential (not shown) and the imaging region 101 and functions as a current source that supplies a constant current to the pixels in the imaging region 101. The V selection circuit 104 selects a specific pixel in the imaging region 101 and sends a signal of that pixel to the CDS circuit 103. The CDS circuit 103 is a circuit that removes amplifier noise and reset noise from the electrical signal obtained from the imaging region 101. A signal from the CDS circuit 103 is output in time series by the H selection circuit 105. The AGC circuit 106 controls the amplitude of the signal from the CDS circuit 103. The ADC 107 converts the analog signal from the CDS 103 into a digital signal. The digital amplifier 108 amplifies this digital signal and outputs it. The TG 109 is a circuit that controls the operation timing of the load transistor 102, the CDS circuit 103, the V selection circuit 104, the H selection circuit 105, the AGC 106, the ADC 107, and the digital amplifier 108. Further, the DSP 110 performs signal processing such as interpolation processing, determination processing, color processing, and color signal extraction. That is, the DSP 110 generates an RGB signal or a YUV signal from the digital signal. The DSP may be provided separately from the solid-state imaging device 100, or may be incorporated in a chip of the solid-state imaging device 100. Further, the TG 109, the AGC 106, the ADC 107, the digital amplifier 108, and the like may be formed on different semiconductor chips. Furthermore, a signal processing circuit not shown in FIG. 1 may be mounted on the chip of the solid-state imaging device 100.

  FIG. 2 is a plan view showing a 4-pixel block of 2 rows and 2 columns as a part of the imaging region 101. The first pixel W includes a colorless filter 10 that transmits the entire wavelength range of visible light, and converts the visible light into a first electric signal. The second pixel R includes a first filter 20 having a spectral transmittance peak at a red wavelength of visible light, and converts the red light having this wavelength into a second electric signal. The third pixel B includes a second filter 30 having a spectral transmittance peak at a blue wavelength of visible light, and converts the blue light having this wavelength into a third electric signal.

  The four-pixel block includes two first pixels W, one second pixel R, and one third pixel B. The pixel region 101 is configured by periodically repeating this unit with the four pixel block as one unit. Thereby, the first pixels W are arranged in a checkered pattern. Between the adjacent first pixels W, the second pixels R and the third pixels B are alternately arranged.

  The imaging area 101 in which the CFA is arranged in this way is arranged in the order of W, R, W, R... In the nth row, and B, W, B, W... In the (n + 1) th row. And in the (n + 2) th row, they are arranged in the order of W, R, W, R. According to this arrangement, the solid-state imaging device 100 outputs an electrical signal for each pixel.

  When the signal of the pixel W is separated from this array, the nth row is SW, *, SW, *..., The (n + 1) th row is *, SW, *, SW. In the (n + 2) line, SW, *, SW, *... Are used, and in the (n + 3) line, *, SW, *, SW. When the signal of the pixel R is separated from the above array, it becomes *, SR, *, SR... In the nth row, *, *, *, *... In the (n + 1) th row, and (n + 2). ), *, SR, *, SR... And (n + 3) th line are *, *, *, *. When the signal of the pixel B is separated from the above array, it becomes *, *, *, * ... in the nth row, and SB, *, SB, * ... in the (n + 1) th row, and (n + 2). ) Line, *, *, *, *... And (n + 3) line SB, *, SB, *. Here, SW, SR, and SB are electric signals (voltage value or current value) obtained from the first pixel W, the second pixel R, and the third pixel B, respectively, that is, visible light intensity or each color. The light intensity is shown. “*” Indicates that the corresponding visible light intensity or the light intensity of the corresponding color is unknown. For example, paying attention to the signal of the first pixel W, the visible light intensity is unknown at the position where the second pixel R and the third pixel B are arranged. Accordingly, “*” is shown at the position where the second pixel R and the third pixel B are arranged. When attention is paid to the signal of the second pixel R, the intensity of red light is unknown at the position where the first pixel W and the third pixel B are arranged. Accordingly, “*” is shown at the position where the first pixel W and the third pixel B are arranged. Further, when attention is paid to the signal of the third pixel B, the intensity of the blue light is unknown at the position where the first pixel W and the second pixel R are arranged. Accordingly, “*” is shown at the position where the first pixel W and the second pixel R are arranged.

  The visible light intensity indicated by “*” or the light intensity of each color is calculated by interpolation processing in the DSP 110 as a calculation unit. As an interpolation processing method, signals from pixels having the same type of CFA adjacent in the vertical direction, the horizontal direction, and the diagonal direction may be arithmetically averaged. For example, the visible light intensity in the second pixel R is calculated by averaging the signals SW from the four first pixels W adjacent to the second pixel R in the vertical and horizontal directions. The average value of the four signals SW may be the visible light intensity in the second pixel R. The visible light intensity in the third pixel B can be obtained similarly. The blue light intensity in the second pixel R is calculated by averaging the signals SB from the four third pixels B obliquely adjacent to the second pixel R. Similarly, the red light intensity in the third pixel B is calculated by averaging the signals SR from the four second pixels R diagonally adjacent to the third pixel B. Further, the red light intensity in the first pixel W is calculated by averaging the signals SR from the two second pixels R adjacent to the first pixel W vertically and horizontally. The blue light intensity in the first pixel W is calculated by averaging the signals SB from the two third pixels B adjacent to the first pixel W in the vertical and horizontal directions. By executing such an interpolation process, three types of color information of SW, SR, and SB in all pixels in the imaging region are obtained. This interpolation processing is executed using signals from 9 pixel blocks in 3 rows and 3 columns. However, the number of pixels used for the interpolation processing can be arbitrarily set according to the interpolation processing capability. In addition, although the arithmetic process uses an arithmetic mean, a method other than the arithmetic mean may be used.

  At this stage, three types of color information of signals SW, SR and SB are obtained in each pixel. The signals SR and SB obtained here are electrical signals for red (R) and blue (B) among the three primary colors (red (R), green (G), and blue (B)). However, the signal SG for green (G) is still unknown. The DSP 110 calculates SG as the fourth electric signal by using the first electric signal SW, the second electric signal SR, and the third electric signal SB in each pixel.

  FIG. 3 is a graph showing the light transmittance of each of the red (R), green (G), and blue (B) color filters and the visible light (W) filter. The horizontal axis indicates the wavelength of incident light, and the vertical axis indicates the light transmittance of each color filter. As indicated by the line LW, the colorless filter used for the first pixel W has a high transmittance exceeding 95% in the entire wavelength region of the visible light region. As indicated by the line LR, the first filter used in the second pixel R has a spectral transmittance peak at a red wavelength, and the spectral transmittance is about 95%. As shown by the line LB, the second filter used in the third pixel B has a spectral transmittance peak at a blue wavelength, but the spectral transmittance is about 80%. Note that the spectral transmittance of a filter having a spectral transmittance peak at a green wavelength (hereinafter referred to as a third filter) used in the prior art is about 80% as shown by a line LG.

  FIG. 4 is a graph showing the spectral sensitivity characteristics of each pixel including the color filter shown in FIG. The horizontal axis represents the wavelength of incident light, and the vertical axis represents the intensity of the optical signal. As shown in FIG. 4, the first pixel W has high spectral sensitivity over the entire wavelength region of visible light. As shown in the graph shown in FIG. 4, the sensitivity SSW of the first pixel W is the sensitivity SSR of the second pixel R, the sensitivity SSB of the third pixel B, and the pixel including the third filter. It is higher than any of the sensitivity SSG (hereinafter referred to as the fourth pixel).

This spectral sensitivity characteristic is due to the fact that the transmittance of the first to third filters is lower than the transmittance of the colorless filter. Therefore, if proportional constants determined by the transmittances of the first to third filters and the spectral sensitivity characteristics of the pixels are Kr, Kb, and Kg, respectively, Equation 2 is established.
SW = Kr × SR + Kb × SB + Kg × SG (Formula 2)

In the specific examples shown in FIGS. 3 and 4, the coefficients Kr, Kb, and Kg are 1.03, 1.23, and 1.23, respectively. Using these proportionality constants, SG is expressed as in Equation 3.
SG = (SW−Kr × SR−Kb × SB) /Kg=0.82SW−0.84SR−SB (Formula 3)
The DSP 110 calculates the signal SG by substituting the signals SW, SR, and SB obtained from the digital amplifier 108 into Equation 3.

  As described above, in the present embodiment, the DSP 110 obtains the coefficients obtained by considering the transmittance of the first filter and the transmittance of the second filter in the second electric signal SR and the third electric signal SB, respectively. Multiply Kr and Kb, respectively. The DSP 110 subtracts the first result (SR (Kr) −SB (Kb)) obtained by this multiplication from the first electric signal SW. The DSP 11 divides the second result (SW-SR (Kr) -SB (Kb)) obtained by this subtraction by the coefficient Kg obtained in consideration of the transmittance of the third filter. Thereby, the DSP 110 calculates the fourth electric signal SG. As in Expression 3, the fourth electric signal SG is obtained by subtracting the component of the red signal SR and the component of the blue signal SB from the visible light signal SW. Hereinafter, this method is referred to as “subtraction method”. By executing this subtraction method, the signal SG1 shown in FIG. 5 can be obtained. The signal SG0 is a signal obtained using a pixel that actually includes the third filter. The signal SG1 substantially matches the signal SG0 in the green wavelength region. This means that the signal SG0 can be calculated almost accurately by the subtraction method.

The DSP 110 may calculate the fourth electric signal SG not only by the subtraction method but also by using division. For example, the DSP 110 may calculate the signal SG using Equation 4.
SG = SW × (SW × Kg / (Kr × SR + Kb × SB) −1) (Formula 4)
Hereinafter, the method using Equation 4 is referred to as “division method”. In the division method, the DSP 110 is determined by the coefficient Kr determined by the spectral transmittance of the first filter and the spectral transmittance of the second filter for each of the second electric signal SR and the third electric signal SB. The coefficient Kb is multiplied, the results obtained by this multiplication are added together, the first electric signal SW is divided by the result (Kr × SR + Kb × SB) obtained by this addition, and the result obtained by this division 1 is subtracted from the first electric signal SW and the result obtained by the subtraction is multiplied. Thereby, the signal SG is calculated.

  By executing this division method, the signal SG2 shown in FIG. 5 can be obtained. The signal SG2 substantially matches the signal SG0 in the green wavelength region. This means that the signal SG0 can be calculated almost accurately by the division method.

The coefficients Kr, Kg and Kb may all be set to 1 in order to simplify the calculation. Thereby, Equation 3 is simplified as Equation 5, and Equation 4 is simplified as Equation 6. The DSP 110 may calculate the signal SG using Equation 5 and Equation 6. Although Equations 5 and 6 are less accurate than Equations 3 and 4, they are relatively simple.
SG = SW-SR-SB (Formula 5)
SG = SW × (SW / (SR + SB) −1) (Formula 6)

  FIG. 6 is a graph showing the relationship between the illuminance of incident light and the signal output of the solid-state imaging device 100. According to this graph, when the illuminance is in the range of I3 to I4, the output VW from the pixel W, the output VR from the pixel R, and the output VB from the pixel B are all not saturated, and from the noise level. Is also big. Therefore, the DSP 110 can calculate the signal SG using any one of the above Equations 3 to 6.

  However, as indicated by the output VW, when the illuminance exceeds I4, the pixel W is saturated. Further, as indicated by the output VB, when the illuminance falls below I3, the output VB falls below the noise level. That is, the solid-state imaging device 100 according to the present embodiment can calculate the signal SG using any one of Equations 3 to 6 in the range of illuminances I3 to I4, but the illuminance is less than I3 and the illuminance is When I4 is exceeded, the signal SG cannot be calculated simply by using any one of Equations 3 to 6. On the other hand, in the device including the pixel R, the pixel G, and the pixel B according to the prior art, the signals SR, SG, and SB are detected in the range of illuminances I3 to I5, as can be understood with reference to the outputs VR, VG, and VB. Can do.

  Therefore, the DSP 110 in the present embodiment performs the calculation shown in FIG. 7 in the low illuminance region below I3 and the high illuminance region above I4. First, the DSP 110 performs the above-described interpolation processing using a signal obtained from the imaging region 101 (S10). Thereby, signals SW, SR and SB in each pixel can be obtained. Outputs VW, VR, and VB shown in FIG. 6 correspond to voltages of signals SW, SR, and SB.

  Next, the output VW of the signal SW is compared with a preset saturation value VW1 (S30). The saturation value VW1 is a value in which the output of the pixel W at the illuminance I4 is set in advance. When the output VW is less than or equal to the saturation value VW1, it can be seen that the outputs VW, VR and VB are all less than or equal to the saturation level. That is, it can be seen that the illuminance of incident light is I4 or less. If the output VW is less than or equal to the saturation value VW1, then the illuminance VR of the signal SR is compared with the noise level VR1 (S40). The noise level VR1 is a value in which the output of the pixel R at the illuminance I7 is set in advance. If the output VR is equal to or higher than the saturation value VR1, then the illuminance VB of the signal SB is compared with the noise level VB1 (S50). The noise level VB1 is a value in which the output of the pixel B at the illuminance I3 is set in advance. When the output VB is equal to or higher than the saturation value VB1 in step S50, it can be seen that the outputs VW, VR, and VB are equal to or higher than the noise level. That is, it can be seen that the illuminance of incident light is I3 or more. In this case, since the illuminance of the incident light is within the range of I3 to I4, the DSP 110 can calculate the signal SG using the signals SW, SR, and SB in Equations 3 to 6. Thereby, signals SR, SG and SB may be generated (S60). Thereafter, the signals SR, SG, and SB are output from the solid-state imaging device 100 (S120).

In step S30, when the output VW exceeds the saturation value VW1, it can be seen that the output VW exceeds the saturation level. That is, it can be seen that the illuminance of incident light exceeds I4. In this case, the DSP 110 calculates the output VW by calculating Equation 7 (S70).
VW = K1 × VR + K2 × VB (Formula 7)
Here, the coefficients K1 and K2 are constants set in advance in consideration of the relationship between VW, VR, and VB when, for example, white light is used as incident light in the region where the illuminance is I3 to I4. The output VW can be expressed by a linear function of the outputs VR and VB as shown in Equation 7. By calculating Expression 7, an output VW corresponding to the illuminance of light incident on the pixel W in a saturated state can be obtained. In FIG. 6, the illuminance and the output are both logarithmically displayed. Further, when the illuminance exceeds I6 and the outputs VR and VB reach the saturation level, the exact output VW cannot be calculated by Equation 7, and VW is saturated. However, since the illuminance of I5 or higher is a saturation level in the prior art, the output VW may be saturated in the case of illuminance of I6 or higher.

  Next, the VW obtained by Expression 7 is compared with the saturation value VW1 (S80). When the output VW is saturated because the illuminance of the green light is large, the exact output VW cannot be calculated using Equation 7. Therefore, in step S80, the DSP 110 determines whether or not the cause of the saturation of the output VW is high illuminance of green light. When the output VW obtained by Expression 7 is equal to or higher than the saturation value VW1, the output VW is saturated with visible light, red light, or blue light (which may include green light). In this case, the DSP 110 executes the first color process (S100). On the other hand, when the output VW obtained by Expression 7 is smaller than the saturation value VW1, the output VW is saturated with green light other than visible light, red light, or blue light. In this case, it is considered that the saturation value VW1 is closer to the actual VW than the output VW obtained by Expression 7. Accordingly, the DSP 110 substitutes the saturation value VW1 for the output VW (S90), and executes the first color processing.

In the first color processing (S100), first, the color information of a certain pixel to be replaced is replaced using the color information of the nearest unsaturated pixel. For example, the DSP 110 substitutes color information (outputs VWp, VRp, and VBp) of pixels adjacent to the left and right of the replacement target pixel in which the output VW is saturated and not saturated in the output VW into Expression 8. The calculated (VW ′, VR ′, VB ′) is used as the color information of the replacement target pixel. In this case, the DSP 110 may use the color information of the replacement target pixel in the color information of the pixel read out immediately before the replacement target pixel in a certain row of the imaging region 101.
VW ′ = (VW / VWp) × VWp
VR ′ = (VW / VWp) × VRp (Formula 8)
VB ′ = (VW / VWp) × VBp

  Next, in step S60, the DSP 110 assigns the color information (VW ′, VR ′, VB ′) of the replacement target pixel after replacement to Equation 3 as (SW, SR, SB), and calculates SG. The calculated SG corresponds to the fourth electric signal VG ′ of the replacement target pixel. Thereby, color information (VR ′, VG ′, VB ′) of the replacement target pixel is obtained.

  Alternatively, the DSP 110 can replace the color information of the replacement target pixel with the color information of the pixels adjacent to the replacement target pixel. In this case, the DSP 110 stores a row read immediately before a certain row in the imaging region 101 in a memory (not shown), and color information of the pixel to be replaced with color information of pixels adjacent vertically. Should be replaced.

  More specifically, the DSP 110 performs an operation for matching the illuminance of the color information of pixels adjacent to the left and right or the top and bottom with the illuminance of the replacement target pixel, and replaces the calculation result as the color information of the replacement target pixel. For example, the color information of the replacement target pixel is set to (VW ′, VR ′, VB ′), and the visible light, red, and blue color information of the pixels adjacent to the replacement target pixel on the left, right, top and bottom are (VWp, VRp, VBp). ). In this case, the color replacement process is performed by calculating Expression 8 and Expression 3 (or Expression 4). When VW is saturated in a plurality of pixels that are continuous in the left-right direction, color replacement processing is performed on the VW saturated pixel that occurs first during the time-series signal readout, and the subsequent VW saturated pixels immediately before The color replacement process is performed using the pixel signal subjected to the color replacement process. The same applies when VW is saturated in a plurality of pixels continuous in the vertical direction.

Further, alternatively, the DSP 110 may perform calculation by achromatic color information of pixels. For example, at high illuminance exceeding I4 or low illuminance below I3, the recognition rate of the color information is reduced by human vision, so that only achromatic luminance information may be sufficient. In such a case, the color information of the pixel may be achromatic and calculated. Rather, it is preferable to perform achromatic color calculation from the viewpoint of not placing a load on the DSP 110. More specifically, the DSP 110 first executes Expression 9.
VW ′ = (VW / W0) × W0
VR ′ = (VW / W0) × R0 (Formula 9)
VB ′ = (VW / W0) × B0
Here, (W0, R0, B0) are constants set in advance by the spectral transmittance of the colorless filter 10, the spectral transmittance of the first filter 20, and the spectral transmittance of the second filter 30. The brightness of (R0, G0, B0) is adapted to VW according to Equation 9. The achromatic signal (R0, G0, B0) is a signal in which R0: G0: B0 = 1: 1: 1.

  Next, in step S60, by substituting (VW ′, VR ′, VB ′) as (SW, SR, SB) into Equation 3 (or Equation 4), the fourth electric signal of the pixel to be replaced as SG VG ′ is obtained. The obtained (VR ′, VG ′, VB ′) is used as the output of the replacement target pixel. Since the calculation of Expression 9 is simpler than the calculation of Expression 8, the calculation by achromatic color does not put a load on the DSP 110. After executing the first color processing, the DSP 110 generates signals SR, SG, and SB as shown in step S60.

  Alternatively, since the achromatic color is R0: G0: B0 = 1: 1: 1, it can be seen that VR ′: VG ′: VB ′ = 1: 1: 1. Therefore, the DSP 110 may only calculate one of VR ′ = (VW / W0) × R0 or VB ′ = (VW / W0) × B0 in Equation 9. For example, the DSP 110 calculates VR ′ = (VW / W0) × R0 and applies the calculation result to VB ′ and VG ′. This eliminates the need to execute Equation 3 (or Equation 4). That is, signals (SR, SG, SB) can be output in step S120 without executing step S60 of FIG.

  On the other hand, if the output VR is smaller than the noise level VR1 in step S40 and if the output VB is smaller than the noise level VB1 in step S50, the second color processing is executed (S110). The second color process may be a replacement process using Expression 8 or an achromatic process using Expression 9. However, the second color processing may be processing different from the first color processing. For example, the first color process may be a replacement process using Expression 8, and the second color process may be an achromatic process using Expression 9. The reverse is also possible.

  For example, in I1 to I3, the output VW from the first pixel W is equal to or higher than the noise level, but the output VR from the second pixel R is lower than the noise level due to low illuminance. In this case, the DSP 110 calculates Expression 8 using outputs VW, VR, and VB from the pixels that are close to the second pixel R and whose outputs VR and VB are equal to or higher than the noise level as the second color processing. At this time, the output VW from the second pixel R is also used. Thereby, (VW ′, VR ′, VB ′) in the second pixel R is obtained.

  Alternatively, the DSP 110 may perform calculation by neutralizing pixel color information as the second color processing. For example, (VW ′, VR ′, VB ′) is obtained by applying the first new electrical SW (output VW) in the second pixel R obtained by the interpolation process to Equation 9.

  After executing the second color processing, the DSP 110 generates signals SR, SG, and SB as shown in step S60. By the second color processing, the signals SR, SG, and SB can be obtained even when the illuminance of the incident light is low illuminance of I3 or less.

  As described above, the conventional apparatus was able to detect incident light in the illuminance range of I3 to I5. In contrast, the solid-state imaging device 100 according to the present embodiment has an illuminance of I1 to I6 by the interpolation process (S10), the output VW calculation process (S70), and the first and second color processes (S100, S110). A range of incident light can be detected. That is, according to the present embodiment, incident light with a low illuminance of I3 or less can be detected.

  As described above, the solid-state imaging device according to the present embodiment introduces the colorless pixel W including the colorless filter that can use the incident light energy of 95% or more, and the monochrome is low in the utilization efficiency of the incident light energy. The pixel G provided with the optical filter is omitted. By introducing a pixel W having a high utilization efficiency instead of the pixel G having a low utilization efficiency of incident light energy, the present embodiment improves the utilization efficiency of incident light energy while increasing the three types of color information (R, G, B) can be obtained. That is, by introducing a pixel W with high utilization efficiency instead of the pixel G with low utilization efficiency of incident light energy, incident light with low illuminance can be detected with high sensitivity. This also leads to further miniaturization of the entire apparatus.

  In the present embodiment, the pixel G is omitted, but the pixel B may be omitted instead of the pixel G. This is because the utilization efficiency of the incident light energy of the pixel B is almost equal to that of the pixel G (about 80%).

(Second Embodiment)
In the case of so-called YUV output instead of RGB output, the same signal processing as in the first embodiment can be applied. The second embodiment is an embodiment in which the first embodiment is applied to YUV output. The configuration of the solid-state imaging device according to the second embodiment may be the same as the configuration of the solid-state imaging device according to the first embodiment.

  As shown in FIG. 8, the second embodiment includes a generation step (S130) of signals SY, SU, and SV instead of the generation step (S60) of signals SR, SG, and SB of FIG. The output step (S140) of the signals SY, SU, SV is provided instead of the output step (S120) of the signals SR, SG, SB. The second embodiment also differs from the first embodiment in achromatic processing.

  The generation of the signals SY, SU, SV in step S130 is performed as follows.

The luminance signal SY is expressed by Expression 10.
SY = 0.30SR + 0.59SG + 0.11SB (Formula 10)
Here, since the CFA according to the present embodiment does not include the pixel G, the DSP 110 calculates the signals SY, SU, and SV from the signals SW, SR, and SB of each pixel obtained by the above-described interpolation processing. For this purpose, the signal SY can be obtained as shown in Equation 11 using Equation 3 and Equation 10.
SY = 0.30SR + 0.58 × (0.82SW−0.84SR−SB) + 0.11SB = 0.48W−0.19R−0.47B (Formula 11)
Further, the color difference signals SU and SV can be expressed as Expressions 12 and 13.
SU = 0.492 × (SB−SY) = 0.492 × (0.53SB + 0.19SR−0.48SW) = 0.26SB + 0.09SR−0.24SW (Formula 12)
SV = 0.877 × (SR−SY) = 0.877 × (0.52SR + 0.47SB−0.48SW) = 0.46SR + 0.41SB−0.42SW (Formula 13)

  Regarding the achromatic processing, (SU, SV) = (0, 0) may be set. Similar to the first embodiment, the second embodiment has an effect that it can detect incident light with lower illuminance than in the past.

(Third embodiment)
In the third embodiment, the signal SW or the interpolated signal is used as it is as the luminance signal SY. Other configurations and processes of the third embodiment may be the same as those of the second embodiment.

The luminance signal SY and the color difference signals SU and SV can be expressed as Expressions 14 to 16, respectively.
SY = SW (Formula 14)
SU = 0.492 × (SB−aSY) (Formula 15)
SV = 0.877 × (SR−bSY) (Formula 16)
However, a and b are constants determined by the spectral transmittance of the blue transmission filter and the red transmission filter and the spectral sensitivity of the photodiode.

  According to the third embodiment, the process (S130) for generating the signals ST, SU, and SV is simplified. Therefore, the load on the DSP 110 is reduced. Furthermore, since the signal SW is directly used as the signal SY, the S / N ratio of the luminance signal SY is improved.

(Variation of pixel array)
Next, a modified example of the pixel arrangement in the imaging region 101 will be described.

  FIG. 9 shows a pixel array composed of four pixels blocks of two rows and two columns, each composed of two pixels W arranged in the row direction and one pixel R and one pixel B arranged in the row direction. . When these four pixel blocks are repeatedly arranged as one unit, the pixels W are arranged in a stripe shape in the row direction. Between the rows of adjacent pixels W, the pixel R and the pixel B are repeatedly arranged. According to this modification, the DSP 110 can calculate the signal SG as in the first to third embodiments. Therefore, this modification can obtain the same effects as those of the first to third embodiments. In addition, according to the pixel array in FIG. 9, only the row of the pixels W can be selectively read using the feature of the CMOS sensor that performs signal reading in units of rows. Thereby, although it is a monochrome image, highly sensitive imaging can be performed at a high frame rate.

  FIG. 10 is the same as the arrangement in FIG. 9 in that the pixels W are arranged in a stripe shape. However, in the arrangement of FIG. 9, the pixel arrangement in a certain column is W, R, W, R... Or W, B, W, B. The pixel array is in the order of W, B, W, R... Or W, B, W, R. As described above, the modification shown in FIG. 10 is configured with an 8-pixel block of 4 rows and 2 columns as one unit. This modification has the same effect as the modification shown in FIG. Furthermore, in the modification shown in FIG. 10, since the pixels R and B are alternately arranged, the color resolution of the signals SR and SB is improved.

  FIG. 11 is the same as the arrangement in FIG. 9 in that the pixels W are arranged in stripes. However, in the arrangement of FIG. 11, the pixel R, the pixel B, and the pixel W are repeatedly arranged between adjacent rows of pixels W. As described above, the modification of FIG. 11 is configured by 6 pixel blocks of 2 rows and 3 columns as one unit. This modification has the same effect as the modification shown in FIG. Furthermore, in the modification shown in FIG. 11, a color image can be taken at a high frame rate by reading only the rows including the pixels R, B, and W.

  FIG. 12 is the same as the arrangement in FIG. 9 in that the pixels W are arranged in a stripe shape. However, in the arrangement of FIG. 12, pixels are repeatedly arranged in the order of W, R, W, B... Or W, B, W, R. In the modification shown in FIG. 12, a 16 pixel block of 4 rows and 4 columns is configured as one unit. This modification has the same effect as the modification shown in FIG. In the modified example shown in FIG. 12, a color image with a high frame rate can be captured by reading out only the rows including the pixels R, B, and W. Further, in the modification example shown in FIG. 12, the ratio of the pixels W in one unit is as high as 75% compared to the modification example shown in FIG. Therefore, even under normal imaging conditions, this modification can perform imaging with higher sensitivity.

  The pixels shown in FIG. 13 are formed in a square shape on a semiconductor substrate. However, the pixels are arranged such that the sides are inclined with respect to the arrangement direction of the pixels W, R, and B. More specifically, each pixel is formed in a square inclined by 45 ° with respect to the vertical and horizontal axes of the imaging surface. In the pixel region 101, adjacent pixels are arranged without a gap. The pixels W are arranged in stripes in the row direction, and W, R, and B are repeatedly arranged between the rows of the pixels W. The pixel region shown in FIG. 13 is composed of 16 pixel blocks of 4 rows and 4 columns as one unit.

  The modification shown in FIG. 13 has the same effect as the modification shown in FIG. Further, in the modified example shown in FIG. 13, since the ratio of the pixel W in one unit is as high as 87.5% in the normal imaging mode, imaging with extremely high sensitivity is possible.

  Each pixel shown in FIG. 14 forms a rectangle, and its width is twice the height. Adjacent pixel rows are shifted from each other by half a pitch. The pixels W are arranged in the row direction every other row and are provided in a stripe shape. Pixels W, R, and B are repeatedly arranged between rows of adjacent pixels W. In the modification shown in FIG. 14, a 16 pixel block of 4 rows and 4 columns is configured as one unit. The modification shown in FIG. 14 has the same effect as the modification shown in FIG. Furthermore, in the modification example shown in FIG. 14, in the normal imaging mode, the ratio of the pixels W in one unit is as high as that in the modification example shown in FIG.

  In the solid-state imaging device using the pixel arrangement shown in FIGS. 10 to 14, a pixel block wider than 3 rows and 3 columns is necessary for performing the interpolation process. Accordingly, when executing the interpolation process, the DSP 110 needs to perform a weighted average process in consideration of the distance between the pixel to be interpolated and the pixel that outputs data used for the interpolation.

  An IR cut filter may be provided for the pixel R and the pixel B other than the pixel W. Thereby, the pixels R and B can detect a more accurate signal without receiving near-infrared light. Furthermore, since the pixel W also detects near-infrared light, it is possible to perform imaging with higher sensitivity.

  In the above embodiment, the CFA is composed of a combination of the pixels W, R, and B. However, among the pixels W, R, and B, the pixels R and B may select any two colors from R, G, and B that are the three primary colors of light.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The figure of the solid-state imaging device according to a 1st embodiment. FIG. 3 is a plan view of an imaging region 101. The graph which shows the light transmittance of a filter. The graph which shows the spectral sensitivity characteristic of a pixel. The graph which shows the result of a subtraction method and a division method. The graph which shows the relationship between the illumination intensity of incident light, and a signal output. The flowchart of the process for producing | generating the signals SR, SG, and SB. The flowchart of the process for producing | generating the signals SY, SU, and SV. The figure which shows the modification of a pixel arrangement | sequence. The figure which shows the modification of a pixel arrangement | sequence. The figure which shows the modification of a pixel arrangement | sequence. The figure which shows the modification of a pixel arrangement | sequence. The figure which shows the modification of a pixel arrangement | sequence. The figure which shows the modification of a pixel arrangement | sequence.

Explanation of symbols

90 ... Semiconductor substrate 100 ... Solid-state imaging device 101 ... Pixel region 110 ... Calculation unit 10 ... Colorless filter 20 ... First filter 30 ... Second filter W ... First pixel R ... Second pixel B ... Third Pixel

Claims (18)

A plurality of first pixels including a colorless filter that transmits the entire wavelength range of visible light, and converting the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit includes a coefficient determined by a spectral transmittance of the first filter and a coefficient determined by a spectral transmittance of the second filter for each of the second electric signal and the third electric signal. multiplied by, this subtracts the result obtained by multiplying the both the first electrical signal, the solid-state imaging device, characterized in that to obtain the fourth electrical signal based on the results obtained by this subtraction. A plurality of first pixels including a colorless filter that transmits the entire wavelength range of visible light, and converting the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit includes a coefficient determined by a spectral transmittance of the first filter and a coefficient determined by a spectral transmittance of the second filter for each of the second electric signal and the third electric signal. , The results obtained by this multiplication are added together, the first electrical signal is divided by the result obtained by this addition, 1 is subtracted from the result obtained by this division, and this subtraction A solid-state imaging device, wherein the fourth electric signal is obtained by multiplying the first electric signal by the obtained result . A plurality of first pixels that include a colorless filter that transmits the entire wavelength range of visible light, and that converts the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals, and using the first to third electrical signals, corresponding to a third wavelength different from the first wavelength and the second wavelength; And an arithmetic unit for calculating the electrical signal of
The arithmetic unit uses the second and third electrical signals from the second and third pixels adjacent to the first pixel to generate the first wavelength based on the first wavelength in the first pixel. Interpolating two electrical signals and a third electrical signal with the second wavelength;
Using the first and third electrical signals from the first and third pixels adjacent to the second pixel, the first electrical signal by the visible light in the second pixel and the first Interpolating a third electrical signal with a wavelength of 2;
Using the first and second electrical signals from the first and second pixels adjacent to the third pixel, the first electrical signal by the visible light in the third pixel and the second Interpolating a second electrical signal with a wavelength of 1;
A solid-state imaging device, and calculates the fourth electrical signal by using said third electrical signal from said first interpolated at each pixel. The pixel region is configured by periodically repeating the unit with a four-pixel block including two of the first pixels and one of the second and third pixels as one unit. The solid-state imaging device according to any one of claims 1 to 3, wherein the solid-state imaging device is provided. The first pixels are arranged in stripes every other row,
Said second and said third pixel, according to claims 1, characterized in that are arranged alternately one on rows of the first pixel adjacent to any one of claims 3 Solid-state imaging device. The first pixels are arranged in stripes every other row,
4. The solid according to claim 1, wherein the first to third pixels are repeatedly arranged one by one between adjacent rows of the first pixels. 5. Imaging device. The first pixels are arranged in stripes every other row,
The first to third pixels are repeatedly arranged in the order of the first pixel, the second pixel, the first pixel, and the third pixel between rows of the adjacent first pixels. The solid-state imaging device according to any one of claims 1 to 3, wherein the solid-state imaging device is provided. 2. The first to third pixels are formed in a quadrangular shape, and are arranged such that sides are inclined with respect to the arrangement direction of the first to third pixels. The solid-state imaging device according to claim 3 . 4. The solid-state imaging device according to claim 1, wherein each of the second and third pixels further includes an infrared cut filter that cuts near infrared light. 5. A plurality of first pixels that include a colorless filter that transmits the entire wavelength range of visible light, and that converts the visible light into a first electrical signal;
A plurality of second pixels including a first filter having a spectral transmittance peak at a first wavelength of visible light, and converting the light of the first wavelength into a second electrical signal;
A second filter having a peak of spectral transmittance at a second wavelength different from the first wavelength of the visible light, and a plurality of third filters for converting the light of the second wavelength into a third electrical signal Pixels,
Receiving the first to third electrical signals generated by light incident on a pixel region comprising the first to third pixels, and using the first to third electrical signals, A solid-state imaging device comprising: a calculation unit that generates a luminance signal and a color difference signal of each of the first to third pixels. The arithmetic unit uses the second and third electrical signals from the second and third pixels adjacent to the first pixel to generate the first wavelength based on the first wavelength in the first pixel. Interpolating two electrical signals and a third electrical signal with the second wavelength;
Using the first and third electrical signals from the first and third pixels adjacent to the second pixel, the first electrical signal by the visible light in the second pixel and the first Interpolating a third electrical signal with a wavelength of 2;
Using the first and second electrical signals from the first and second pixels adjacent to the third pixel, the first electrical signal by the visible light in the third pixel and the second Interpolating a second electrical signal with a wavelength of 1;
The solid-state imaging device according to claim 10 , wherein the luminance signal and the color difference signal are generated using the first to third electric signals after interpolation in each pixel. The solid-state imaging device according to claim 10 , wherein the calculation unit uses the first electric signal after interpolation as the luminance signal. When the first electric signal from the first pixel exceeds a set value due to high illuminance, the arithmetic unit is configured to output the second electric signal and the third electric signal of the first pixel, and The first to third electrical signals in the first pixel are calculated using the first to third electrical signals of the pixel that is close to the one pixel and the first electrical signal is equal to or less than the set value. using the third electrical signal from the first this calculated, according to claims 1, characterized in that calculating a fourth electrical signal of a pixel first in any of claims 3 Solid-state imaging device. When the output from the first pixel exceeds a set value due to high illuminance, the arithmetic unit performs the second electric signal and the third electric signal of the first pixel, and the second electric signal. The spectral transmittance of the colorless filter, the spectral transmittance of the first filter, and the second filter so that the ratio of the third electrical signal and the fourth electrical signal satisfies 1: 1: 1. First to third electric signals of the first pixel are calculated using a constant determined based on the spectral transmittance, and the fourth electric signal is calculated using the calculated first to third electric signals. The solid-state imaging device according to any one of claims 1 to 3, wherein the electrical signal is calculated. When the output from the first pixel exceeds a set value due to high illuminance, the arithmetic unit performs the second electric signal and the third electric signal of the first pixel, and the second electric signal. The spectral transmittance of the colorless filter, the spectral transmittance of the first filter, and the second filter so that the ratio of the third electrical signal and the fourth electrical signal satisfies 1: 1: 1. The second or third electric signal of the first pixel is calculated using a constant determined based on the spectral transmittance, and the fourth or third electric signal is calculated using the calculated second or third electric signal. The solid-state imaging device according to any one of claims 1 to 3, wherein the electrical signal is calculated. When the second electric signal from the second pixel or the third electric signal from the third pixel becomes less than a set value due to low illuminance, the arithmetic unit is configured to output the second pixel or the second pixel. First to third electrical signals from a pixel that is close to the third pixel and whose second and third electrical signals are equal to or greater than a set value, spectral transmittance of the colorless filter, spectral of the first filter The first to third electrical signals in the second pixel or the third pixel are calculated using the transmittance and a constant determined by the spectral transmittance of the second filter, and the calculated 4. The solid-state imaging device according to claim 1, wherein the fourth electrical signal is calculated using first to third electrical signals. 5. When the output from the second pixel or the third pixel becomes less than a set value due to low illuminance, the calculation unit is configured to output the first electric signal in the second pixel or the third pixel. The spectral transmittance of the colorless filter and the spectral transmittance of the first filter so that the ratio of the second electrical signal, the third electrical signal, and the fourth electrical signal satisfies 1: 1: 1. And the first to third electrical signals of the second pixel or the third pixel are calculated using the constant determined based on the spectral transmittance of the second filter, and the calculated first 4. The solid-state imaging device according to claim 1, wherein the fourth electric signal is calculated using the first to third electric signals. 5. When the output from the second pixel or the third pixel becomes less than a set value due to low illuminance, the calculation unit is configured to output the first electric signal in the second pixel or the third pixel. The spectral transmittance of the colorless filter and the spectral transmittance of the first filter so that the ratio of the second electrical signal, the third electrical signal, and the fourth electrical signal satisfies 1: 1: 1. And the second or third electrical signal of the second pixel or the third pixel is calculated using a constant determined based on the spectral transmittance of the second filter, and the calculated second 4. The solid-state imaging device according to claim 1, wherein the fourth electrical signal is calculated using 2 or a third electrical signal. 5.

Images