JP2003333605A - Image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image pickup device which realizes pixel addition driving which doesn't change color reproduction of a color balance or the like and, especially, is free from degradation in image quality even in the case that a substrate bias voltage is varied. <P>SOLUTION: The image pickup device is provided with a substrate bias voltage VSUB setting part 202 for variably setting a value of the substrate bias voltage of a CCD imaging device 5 and a white balance setting and color correction part 203 for performing color correction of an image pickup signal outputted from the CCD imaging device 5 in accordance with the value of the substrate bias voltage set by the substrate bias voltage VSUB setting part 202. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus using a solid-state image pickup element such as a CCD, and more particularly to an image pickup apparatus which varies a substrate voltage of the image pickup element.

[0002]

2. Description of the Related Art In recent years, various electronic cameras using solid-state image pickup devices such as CCD have been developed. In this type of electronic camera, a captured image signal is obtained by photoelectrically converting a subject image with a CCD image sensor. Further, in order to read out pixel charges from the CCD image pickup device, a drive system for reading out each pixel charge individually for each line is usually used, but various special drive systems are known in addition to this.

As an example of a typical special drive system, a so-called "n-fold speed vertical addition drive (n addition drive) system", which is a drive system for high-speed and high-sensitivity reading, is known. In this n-addition driving method, the number of pixels (the number of transfer clocks) transferred from the vertical (V) transfer path to the horizontal transfer path in each horizontal (H) blanking period is set to "2" or more instead of the normal "1". By setting the integer value n, the charges of n pixels (n lines) are sequentially transferred to the horizontal transfer path, and the charges of n pixels (n lines) added in the horizontal transfer path are changed to 1 pixel (1 Line).

As a result, the number of vertical lines corresponding to one screen becomes 1 / n, and as a result, the read time for one screen becomes 1 / n, and high-speed reading is possible. Further, since the charge amount is increased n times by the charge addition at the time of transfer, there is a feature that a sensitivity increasing effect corresponding thereto can be obtained.

However, when the "n addition drive" as described above is performed, the sensitivity increasing effect can be obtained, but when a high-luminance subject is imaged, a white streak-like pseudo signal ( Fog noise such as blooming and smear) may occur, which may be accompanied by new image quality deterioration.
This phenomenon will be described below.

There is no problem if the saturation level (maximum amount of charge that can be transferred) of the horizontal transfer path to which the charges are added is infinite, but this saturation level is actually finite. Therefore, the saturation level SatH is designed so as to correspond to the saturation level of the photoelectric conversion unit in the normal driving state which is the non-n-addition driving in the normal case. In other words, the saturation level of the photoelectric conversion unit is the overflow level of the charge storage unit, and even if photocharges exceeding this level are generated, they are discharged to the overflow drain and are not stored. The overflow level OFL can be varied by the set value of the substrate bias voltage VSUB described later. However, if the overflow level OFL is set too high, blooming easily occurs. Therefore, the overflow level OFL usually becomes as high as possible within the allowable limit of blooming characteristics. Is set.

That is, the saturation level S of the horizontal transfer path
AtH is generally a value that allows for some design margin or adjustment margin with respect to the standard setting of the overflow level OFL of the charge storage portion, and a value higher than that is not set. It is rare. If this is written symbolically, SatH = k × OFL (k = 1.1-1.5 or so, but the theoretical lower limit is 1).

Therefore, if "n addition drive" is performed, the pixel signal is multiplied by n by addition and the saturation level S is reached.
The charges exceeding atH are input to the horizontal transfer path.
Specifically, this occurs in the case where the charge amount before addition per pixel exceeds SatH / n (<OFL).

Even if such an excessive charge is input, if the horizontal transfer path is provided with a sufficient countermeasure against the excessive charge, for example, by setting an overflow drain, it is simply clipped at the saturation level SatH. However, in the actual CCD image pickup device, there are some measures against excess charges in the horizontal transfer path which are insufficient. When this type of CCD image pickup device is used, the excess charges are adjacent to the horizontal transfer path. There is a risk that the same fog phenomenon as that of blooming may occur along the horizontal line because it overflows into the area.

To solve this problem, the applicant of the present invention uses the substrate bias voltage V of the solid-state image pickup device when the n addition mode is used.
By previously controlling the set value of the SUB, the overflow level of the corresponding charge accumulating section is lowered to prevent excessive charges from being input to the horizontal transfer path and prevent the fog phenomenon from occurring. There is. (Patent application 200
0-069154)

[0011]

In the invention of Japanese Patent Application No. 2000-069154 filed by the present applicant, as described above, the fog phenomenon is prevented by preventing excessive charges from being input to the horizontal transfer path. That is, this is a very useful invention, but in the n-addition mode, the color balance changes as compared with the non-addition mode. This is because the setting of the substrate bias voltage VSUB is changed significantly. That is, since the sensitivity characteristic of the photoelectric conversion storage unit has a dependency on the substrate bias voltage VSUB, and the dependency is larger on the long wavelength side, the spectral characteristic also has a VSUB dependency. This means that the RGB relative sensitivities of the image sensor change.

As shown in FIG. 6 (numerical value on the horizontal axis is wavelength: unit nm), if the spectral characteristic of the camera in the normal state is represented by a solid line, the relative spectral characteristic will be obtained when pixels are added (the substrate bias voltage VSUB).
B is increased and R is decreased with G as a reference.

Conventionally, although the substrate bias voltage VSUB is finely adjusted during the adjustment of the camera manufacturing process, it is often used almost fixedly thereafter. In this case, the above-mentioned spectral characteristic Changes could be neglected or absorbed during basic adjustment. However, as in the above-mentioned prior application by the applicant, a large substrate bias voltage VS
This is a problem when changing the UB settings when using the camera.

The present invention has been made in view of the above problems, and even when the substrate bias voltage is changed, color reproduction such as color balance does not change, and image pickup for realizing pixel addition drive without deterioration of image quality is achieved. The purpose is to provide a device.

[0015]

A first image pickup device of the present invention is a solid-state image pickup device, driving means for driving the solid-state image pickup device, and a substrate for variably setting a value of a substrate bias voltage of the solid-state image pickup device. A white balance for performing color correction for a light source type by providing a bias voltage setting means and a gain setting means for setting an independent gain value for each color component of the image pickup signal output from the solid-state image pickup device. And a white balance adjusting means for adjusting the relative intensity of each color component output that changes according to the value of the substrate bias voltage set by the substrate bias voltage setting means, with respect to each of the independent gain values. It is characterized by further comprising data correction means for multiplying a color correction amount which is a preset numerical value as an inverse ratio.

A second image pickup apparatus of the present invention is characterized in that, in the first image pickup apparatus, each color component of the image pickup signal is three primary colors RGB of additive color mixture.

According to a third image pickup device of the present invention, in the first or second image pickup device, each of the solid-state image pickup devices is read when the solid-state image pickup device is driven by the driving means to read out pixel charge as an output signal. There is a pixel charge read control unit capable of reading in a normal drive mode for individually reading out pixel charges and an n addition drive mode for reading out by adding a predetermined number n of pixel charges in the solid-state imaging device in the vertical direction. However, the substrate bias voltage setting means controls the substrate bias voltage to different set values depending on whether the reading by the pixel charge reading control means is the normal drive mode or the n-addition drive mode. Characterize.

According to a fourth image pickup device of the present invention, in the first or second image pickup device, each of the solid-state image pickup devices when the solid-state image pickup device is driven by the driving means to read pixel charge as an output signal. There is a pixel charge read control means capable of reading in an n addition drive mode in which a predetermined number n of pixel charges are added in the vertical direction and read, and the substrate bias voltage setting means reads by the pixel charge read control means. It is characterized in that the substrate bias voltage is controlled to different set values according to the value of n in.

A fifth image pickup device of the present invention comprises a solid-state image pickup element, a driving means for driving the solid-state image pickup element, and a substrate bias voltage setting means for variably setting the value of the substrate bias voltage of the solid-state image pickup element. Color correction means for performing color correction on the image pickup signal output from the solid-state image pickup element according to the value of the substrate bias voltage set by the substrate bias voltage setting means; and the solid-state image pickup element driven by the driving means to reduce pixel charge. When reading out as an output signal, a pixel charge read control unit capable of reading in an n addition drive mode in which each pixel charge of the solid-state image sensor is vertically added by a predetermined number n (n ≧ 2) and read. The substrate bias voltage setting means sets the substrate bias voltage differently according to the value of n in the reading by the pixel charge reading control means. And controlling the.

A sixth image pickup apparatus of the present invention is characterized in that, in the fifth image pickup apparatus, the color correction corrects white balance adjustment for the image pickup signal.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an image pickup apparatus which is an embodiment of the present invention. In addition, here, a case where the digital camera is realized will be described as an example.

As shown in FIG. 1, a digital camera 100 of this embodiment has a lens system 101 including various lenses.
A lens drive mechanism 102 for driving the lens system 101, an exposure control mechanism 103 for controlling the diaphragm of the lens system 101, an optical filter 104 for low-pass and infrared cut, and a CCD with a color filter. A color image pickup device 105, a CCD driver 106 for driving the image pickup device 105, a pre-process circuit 107 including an A / D converter, a color signal generation process, a matrix conversion process, and various other digital processes. A digital process circuit 108, a card interface 109 for attaching / detaching an external memory card 110, and an LC
And a D image display system 111.

Further, the digital camera 100 has a system controller (CP) for centrally controlling each section.
U) 112, and further an operation switch system 113 including various operation buttons, an operation display system 114 for displaying an operation state and a mode state, a strobe 115 as a light emitting means, and the lens drive mechanism 102. Exposure control driver 117 for controlling the lens driver 116, strobe 115 and exposure control mechanism 103 of
Non-volatile memory (EE) for storing various setting information
PROM) 118.

In the digital camera 100 of the present embodiment, the system controller 112 centrally controls all the operations, and the CCD image pickup device 1 is operated by the CCD driver 106.
Drive (05) is controlled to perform exposure (charge accumulation) and signal reading, and the read signal is used as the preprocessing circuit 10
Card interface 109 through the digital processing circuit 108 through various signal processing
The data is recorded on the removable memory card 110 via the.

When the strobe 115 is used for the above exposure, the strobe 11 is controlled by controlling the exposure control driver 117 under the control of the system controller 112.
5, the strobe 115 is caused to emit light by sending control signals for starting and stopping the light emission.

The drive control of the CCD image pickup device 105 is performed using various drive signals (charge transfer pulse TG, vertical drive pulse, horizontal drive pulse, substrate bias voltage VSUB, etc.) output from the CCD driver 106. Be seen.

In the present embodiment, as the CCD color image pickup device 105, for example, an interline type using a vertical overflow drain structure is adopted. That is,
It is provided with a charge storage section arranged in a matrix and a charge transfer section (vertical charge transfer path, horizontal charge transfer path) respectively arranged horizontally and vertically.

When the charge transfer pulse TG is output, the transfer gate provided between each charge storage section and the vertical charge transfer path is opened, and the charge is transferred from each charge storage section to the corresponding vertical charge transfer path. It At that time, the substrate bias voltage VSUB
The exposure time is substantially controlled by the relative relationship between the output timing of the charge discharge pulse and the output timing of the charge transfer pulse TG that are superimposed on. The vertical charge transfer path is driven by a vertical drive pulse. The substrate bias voltage VSUB is used to define the overflow level of the charge storage section. Excess charge above the overflow level is drained to the overflow drain.

In the digital camera 100 of the present embodiment, the same operation and control as a normal digital camera is performed except for the variable setting control of the substrate bias voltage VSUB and the operation related to the color correction corresponding thereto which will be described in detail below. This known part is performed
The description here is omitted.

The system controller 112 has a function for performing variable setting control of the substrate bias voltage VSUB, which is a feature of this embodiment, as a drive mode control unit 201.
And VSUB setting unit 202, white balance (W
B) A setting and color correction unit (hereinafter, white balance setting unit) 203 is provided.

The drive mode control unit 201 is for controlling the readout of pixel charges from the CCD image pickup device 105, and controls the digital camera 100 in the normal drive mode and the n-addition drive mode. Here, the normal drive mode is a drive control mode for individually reading out each pixel charge of the CCD image sensor 105, and the n addition drive mode is a predetermined number n of each pixel charge of the CCD image sensor 105 in the vertical direction. This is a drive control mode for adding and reading. FIG. 2 shows how the drive control is performed in the normal drive mode and the n-addition drive mode.

FIG. 2A shows the drive timing in the normal drive mode. As shown in the figure, one transfer drive using the vertical drive pulse φV is executed every horizontal blanking period (HBLK), and one line of charge is transferred from the vertical transfer path to the horizontal transfer path (vertical 1 for each transfer path
Pixels). For the transfer on the vertical transfer path, for example, a well-known four-phase drive method or the like can be used.

On the other hand, FIG. 2B shows the drive timing in the n addition drive mode (here, n = 4).
The transfer drive is performed four times using the vertical drive pulse φV for each horizontal blanking period (HBLK), and charges of four lines are transferred from the vertical transfer path to the horizontal transfer path (the vertical direction of each vertical transfer path). 4 pixels).

Incidentally, the driving of the horizontal transfer path is executed in the n addition driving mode as in the normal driving mode.
As a result, in the n addition drive mode, the image compressed to 1 / n in the vertical direction is read at high speed. In the present embodiment, the readout control in the n addition drive mode is performed prior to the shooting, for example, AF (automatic focusing).
And used for AE (automatic exposure compensation) processing and the like. Of course, it can also be used for displaying a moving image (EVF) of a captured image on the LCD image display system 111.

As a development of the n addition drive mode,
For the purpose of considering the color coating pattern in the CCD image pickup device 105 and appropriately adjusting the sensitivity, when the charge is transferred from the charge storage unit to the vertical transfer path prior to the vertical transfer, the charge is transferred from the vertical transfer path to the horizontal transfer path. It is also possible to use the "m / n addition drive" that selectively transfers only a specific m (≤n) line of the n lines to be added at the time of transfer ("n addition drive" is a special case. m =
n is included as “n / n addition drive”), but since the number of pixel charge additions when using these drives has an essential meaning in the present embodiment, m is used when m / n addition drive is used.
Therefore, in order to simplify the description, in the present specification, the case of m = n, that is, only the n-addition drive will be described below. Therefore,
When the present invention is applied to m / n addition drive, m is read as n.

The VSUB setting section 202 is for variably setting the overflow level OFL of the charge storage section which is determined by the substrate bias voltage VSUB described above, and is the substrate bias voltage in the normal drive mode and the n addition drive mode. Control to set VSUB to different values.
Further, in the n addition drive mode, the set value of the substrate bias voltage VSUB is variably set according to the value of n.

FIG. 3 is an explanatory view showing a cross-sectional structure of an interline CCD having a vertical overflow drain structure, which is used as the CCD image pickup device 105 in the digital camera of this embodiment.

As shown in FIG. 3, an N-type semiconductor substrate 400 is provided.
Is a shallow P junction first region 401 of the well and a deep P junction
And the second region 402 of the well. The region portion of the first region 401 where the junction N-type region is formed is a photodiode, a so-called photoelectric conversion region (charge storage unit) 403.
Acts as.

In the second region 402, a vertical shift register consisting of a buried channel 404, that is, a transfer electrode 405 is formed. A transfer electrode 405 is arranged on the main surface with an insulating layer 406 interposed. The photoelectric conversion region 403 and the buried channel 404 are separated by a channel stop region 407 made of a high P-type impurity layer.

Further, the transfer gate region 408 is provided between the buried channel 404 corresponding to the photoelectric conversion region 403.
Are arranged. Further, the area other than the photoelectric conversion region 403 is shielded by the metal layer 409. Blooming suppression is N
The substrate bias voltage VSUB 411, which is a reverse bias voltage, is applied to the junction between the type semiconductor substrate 400 and the first region 401 and the second region 402 of the P well to apply the photoelectric conversion region 40.
It is realized by completely depleting (depleting layer) the first region 401 of the P well immediately below 3.

FIG. 4 is a diagram showing the change characteristic of the saturation signal amount (overflow level OFL) of the charge accumulating portion with respect to the substrate bias voltage VSUB in the digital camera of this embodiment.

As shown in the figure, the substrate bias voltage VSU
The overflow level OFL can be lowered by increasing the absolute value of B.

Next, referring to Table 1, the pixel addition number (n)
The specific relationship between the substrate bias voltage VSUB and the substrate bias voltage VSUB will be described.

[0045]

[Table 1] At the time of non-addition, that is, in the normal drive mode of n = 1, the default substrate bias voltage VSUB value is set to "9".
V ", the overflow level OFL corresponding to this VSUB value is set to" 740 mV ", and this is used as a reference value.

Table 1 shows the digital camera 10 of this embodiment.
0 stored in advance as preset data, n
In addition drive mode (for example, 2 pixel addition, 4 pixel addition)
3 shows the set value of the substrate bias voltage VSUB at the time.

In the normal drive mode (substrate bias voltage VSUB = 9V, overflow level OFL = 740)
For n = 2, that is, when two pixels are added, the value of the substrate bias voltage VSUB (12. 2V) is calculated from the characteristics of FIG. 4, and in the present embodiment, this value is used as the substrate bias voltage VSU.
Used as the setting value of B. Similarly, n = 4, that is, the value of the substrate bias voltage VSUB (14.5 V) is set so that the overflow level of the charge storage unit becomes 1/4 the value (185 mV) at the time of non-addition when adding four pixels. Use as a value.

The digital camera 100 of the present embodiment uses the substrate bias voltage VSU at the time of addition of the respective pixels thus obtained.
The set value of B, that is, the contents of Table 1 above is preset as preset data in a predetermined memory (for example, EEPROM 118).
It is designed to be memorized in.

Since the saturation level of the horizontal transfer path is generally at least the standard setting value (740 mV) of the overflow level OFL of the charge storage section,
Thus, the overflow level OFL (7
Even if the set value of the substrate bias voltage VSUB is determined only by the ratio of the number of pixels added during non-addition with respect to 40 mV), horizontal fog noise can be reliably prevented.

The white balance setting section 203 has a normal white balance function including an automatic white balance, and an n addition drive mode (in the present embodiment, 2).
It has a function of performing color correction according to the value of the substrate bias voltage VSUB set in pixel addition, four pixel addition).

Here, the white balance setting section 20
As the third function, the operation principle of the white balance circuit adopted in this embodiment (the above-mentioned normal white balance function) will be briefly described.

That is, the white balance setting section 2
Reference numeral 03 denotes a light source type (eg, “daylight”, “incandescent lamp”, “fluorescent lamp”) depending on the color temperature information of the subject and other information (including user setting and “strobe use” information).
“Strobe” or the like) is detected, and preset in a predetermined memory (for example, EEPROM 11) according to the detection result.
White balance is achieved by multiplying each of the R and B signals by a predetermined gain value stored in (8). Therefore, there are as many sets of preset R and B gain values (white balance preset data) as the number of assumed light source types. (At this time, needless to say, even if the same incandescent lamp has a different color temperature, it is handled as a different light source if necessary.) And when automatically detecting the light source type, it functions as a so-called auto white balance. However, when the light source type is designated as "daylight" by manual setting, this functions as a so-called manual (preset selection) white balance. The illustration of the value of the white balance preset data is omitted.

Now, consider a case where the white balance function is executed based on only one preset data for each light source type without considering the change in the spectral sensitivity of the image pickup device. In this case, if the spectral sensitivity of the image sensor changes, the change causes an imbalance of R, G, and B. That is, each preset data is normal (not added)
Since the optimum value is set for the signal output in the drive mode, when the substrate bias voltage VSUB is changed between the normal drive mode and the n-addition drive mode as in the digital camera 100 of this embodiment, it is not Spectral sensitivity changes when n pixels are added (in n addition drive mode) compared to addition (in normal drive mode), so the white balance function is executed with no presetting data without any measures. Then, the color changes as it is.

Therefore, the digital camera 10 of the present embodiment
In order to cope with such a situation, the white balance setting unit 203 of 0 changes the substrate bias voltage VSUB during non-addition (in the normal drive mode) during n-pixel addition (n
In addition drive mode), the substrate bias voltage VSU
The color correction (B correction, R correction) according to B is performed.

In Table 2, when non-addition (in normal drive mode),
Substrate bias voltage VSUB value at the time of 2-pixel addition and 4-pixel addition (n-addition drive mode), R, G, B characteristics due to the changing substrate bias voltage VSUB, and color correction amount (each preset data of R and B) The R correction amount and the B correction amount, which are the respective numerical values of R and B to be multiplied by.

[0056]

[Table 2] That is, B / G / R shown in the middle row of Table 2 means the relative intensity of each RGB color signal output (each curve in FIG. 6) corresponding to the change in the spectral characteristic of the camera of this embodiment illustrated in FIG. (Corresponding to the area surrounded by the horizontal axis) and G = 100. In general, the RGB outputs before white balance adjustment are not necessarily equal, and B: G: R = 92: 100: 96 in the non-addition state.

As described above, since the preset data is optimized with respect to this non-addition state (for each assumed light source), no correction is necessary in this non-addition state. The correction amounts of R, B, and B are all 1. On the other hand, for example, when adding two pixels, the output of B is 100/92 times, so the B correction amount to be multiplied to cancel this is 92/100 = 0.92, and the output of R is 92/96 times. Therefore, the R correction amount to be multiplied to cancel this is 96/92 = 1.0
It becomes 4. The same applies when adding four pixels.

FIG. 5 is a flowchart showing a routine for performing color correction on the set value of the substrate bias voltage VSUB in the digital camera 100 of this embodiment.

As shown in the flowchart of FIG. 5, the system controller 112 first inputs the color temperature information of the subject and other information (step S1). Based on this information, preset data at the time of non-addition stored in a predetermined memory in advance is selected (step S2), and it is detected whether the substrate bias voltage VSUB is variable, that is, whether n pixels are added. (Step S3). Here, in the case of non-addition in which the substrate bias voltage VSUB is not variable, the selected preset data is directly adopted to set the white balance (step S).
5). That is, the normal white balance setting is performed. (Note that since the correction amounts of R and B are 1, the correction is not performed in FIG. 5, but when the process is shared by avoiding the branch in step S3, the correction amount 1 is multiplied. On the other hand, in the case of n addition in which the substrate bias voltage VSUB is variable, the selected preset data is added to the selected preset data. Correction amount, or 3 when adding 4 pixels
After the color correction is performed by multiplying the correction amount of the step (step S4), the white balance is set (step S4).
5). That is, white balance is executed by performing B correction and R correction on the normal white balance setting.

In the above, the white balance correction corresponding to the substrate bias value is realized by multiplying the preset data at the time of non-addition by each correction amount of R and B. However, after performing such correction, It goes without saying that the present invention can be equally realized by a method of storing data as preset data in advance and selecting these as required.

As described above, according to the digital camera of this embodiment, color reproduction such as color balance does not change even when the substrate bias voltage VSUB is changed. Therefore, it is possible to realize the pixel addition drive with no deterioration in image quality.

In the present embodiment, the white balance is adjusted as the color correction. However, the present invention is not limited to this, and attention is paid to the fact that a change in spectral sensitivity may cause a change in color reproduction. It is also possible to correct so that this change in color reproduction does not occur by changing the. In this case, unlike the white balance shift, it may not be possible to correct all colors, but it is possible to correct at least specific colors such as skin color and green.

The technical idea of the present invention can also be applied to a camera that uses only pixel addition (that is, does not have a non-addition mode).

Further, the color correction data (the above-mentioned color correction amount) corresponding to the substrate bias voltage VSUB may have different required set values due to the performance variation of each device. In this case, At the time of adjustment in the manufacturing process etc., set data individually required for correction data EEPRO
It is more desirable to write to M118.
That is, the color correction corresponding to the substrate bias voltage VSUB, which is the main part of the present invention, is thereby made by so-called electronic adjustment (individual setting data is adaptively made different for each device so as not to cause variation in the result). It will be feasible in the included form.

[0065]

As described above, according to the present invention, even when the substrate bias voltage is changed, the color reproduction such as the color balance does not change, and it is possible to realize the pixel addition drive without the image quality deterioration. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an image pickup apparatus which is an embodiment of the present invention.

FIG. 2 is a diagram showing drive timing in a normal drive mode in the embodiment.

FIG. 3 is a diagram showing a drive timing in an n addition drive mode (here, n = 4) in the embodiment.

FIG. 4 is a substrate bias voltage VS in the above embodiment.
FIG. 6 is a diagram showing a change characteristic of a saturation signal amount (overflow level OFL) of a charge storage unit with respect to UB.

FIG. 5 is a substrate bias voltage VS in the above embodiment.
7 is a flowchart showing a routine for performing color correction on the set value of UB.

FIG. 6: Spectral characteristic of camera in normal state (solid line)
3 is a diagram showing relative spectral characteristics (broken line) at the time of pixel addition.

[Explanation of symbols]

105 ... CCD image sensor 112 ... System controller 118 ... EEPROM 201 ... Drive mode control unit 202 ... Substrate bias voltage VSUB setting unit 203 ... White balance setting and color correction unit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4M118 AA05 AA10 AB01 BA13 DA03                       DB09 DB20 FA06 FA13 FA26                       FA35 GB03 GB08 GB11                 5C065 BB01 BB02 BB24 DD02

Claims (6)

[Claims] 1. A solid-state image sensor, driving means for driving the solid-state image sensor, substrate bias voltage setting means for variably setting a value of a substrate bias voltage of the solid-state image sensor, and an image output by the solid-state image sensor. For each color component of the signal, a white balance adjusting means for performing color correction for the light source type by providing a gain setting means for setting an independent gain value for each color component, and the white balance adjusting means, Each of the independent gain values is multiplied by a color correction amount, which is a numerical value set in advance as an inverse ratio of the relative intensity of the output of each color component that changes according to the value of the substrate bias voltage set by the substrate bias voltage setting means. An image pickup apparatus further comprising a data correction unit. 2. The image pickup apparatus according to claim 1, wherein each color component of the image pickup signal is RGB of three additive primary colors. 3. A normal drive mode in which each pixel charge of the solid-state image pickup device is individually read when the solid-state image pickup device is driven by the driving means to read out pixel charge as an output signal, and each pixel of the solid-state image pickup device. There is a pixel charge read control means capable of reading in an n addition drive mode in which a predetermined number n of charges are added and read in the vertical direction, and the substrate bias voltage setting means has a pixel charge read control means for reading. The image pickup apparatus according to claim 1, wherein the substrate bias voltage is controlled to different set values depending on whether the normal drive mode or the n-addition drive mode is set. 4. An n addition drive mode in which when driving the solid-state imaging device by the driving means to read pixel charges as an output signal, each pixel charge of the solid-state imaging device is vertically added by a predetermined number n and read. And a substrate bias voltage setting unit that controls the substrate bias voltage to a different set value according to the value of n in the reading by the pixel charge read control unit. The image pickup apparatus according to claim 1, wherein the image pickup apparatus is provided. 5. A solid-state image sensor, drive means for driving the solid-state image sensor, substrate bias voltage setting means for variably setting the value of the substrate bias voltage of the solid-state image sensor, and the substrate bias voltage setting means. Color correction means for performing color correction on the image pickup signal output from the solid-state image pickup element according to the value of the substrate bias voltage, and the solid-state image pickup element when the solid-state image pickup element is driven by the driving means to read pixel charge as an output signal. Pixel charge read control means that enables reading in an n addition drive mode in which each pixel charge of the image sensor is added and read in the vertical direction by a predetermined number n (n ≧ 2), and the substrate bias voltage setting is performed. The means controls the substrate bias voltage to a different set value according to the value of n in the reading by the pixel charge reading control means. Image pickup device. 6. The image pickup apparatus according to claim 5, wherein the color correction corrects white balance adjustment for the image pickup signal.