JP2002333570A - Imaging device, camera and method of controlling imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of focus detection by controlling the outputs of respective photoelectric conversion regions of the same pixels in such a manner that these outputs are made nearly equal to each other even when the quantities of the incident light on the respective photoelectric conversion regions vary. SOLUTION: The image pickup device for making the photoelectric conversion of the incident optical images through a photographic lens 5 has the plural pixels having the tow photoelectric conversion regions α and β within each pixel. The device is so constituted that the photoelectric conversion regions on the side nearer the optical axis of the imaging lens among the photoelectric conversion regions within the plural pixels and the photoelectric conversion regions on the side more distant from the optical axis can be respectively independently controlled.

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, a camera, and a control method of the image pickup apparatus. More specifically, the present invention relates to a pupil division type focus detection system that receives light beams transmitted through different positions of a pupil of a photographing lens. The present invention relates to an imaging device that can be used, a camera equipped with the imaging device, and a control method of the imaging device.

[0002]

2. Description of the Related Art As one of the systems for detecting the focus state of a photographing lens, there is an apparatus for performing a pupil division type focus detection using a two-dimensional sensor in which a micro lens is formed in each pixel of the sensor. JP-A-55-111928 and JP-A-5-119528
No. 8-24105.

The applicant of the present invention has disclosed a device for performing a pupil division type focus detection using a CMOS image sensor (imaging device) used in a digital still camera.
6815.

FIG. 16 is a view for explaining the principle of a pupil division type focus detection method using an image sensor proposed in Japanese Patent Application No. 11-306815, and FIG. 17 shows a part of a pixel layout of the image sensor. It is a schematic plan view. The image sensor 10 is arranged on a predetermined imaging plane of the taking lens 5. Each pixel of the image sensor 10 is composed of two photoelectric conversion regions 13α and 13β, and the micro lens 1 formed on the photographing lens side of each photoelectric conversion region.
1, the photoelectric conversion regions 13α and 13β are set so as to have a substantially image-forming relationship with the pupil of the photographing lens 5.

Here, the photoelectric conversion region 13α receives a light beam that passes above the pupil of the photographing lens 5 in the figure, and the photoelectric conversion region 13β receives a light beam that passes below the pupil of the photographing lens 5 in the diagram. At the time of focus detection, as shown in FIG. 17, the outputs from the photoelectric conversion area α and the photoelectric conversion area β are read out independently, and an image formed by a light beam transmitted through different pupil positions of the photographing lens from outputs from a plurality of pixels is further formed. Generated.

A method of performing focus detection using an image generated from a light beam transmitted through different pupil positions of a photographing lens is a known technique as disclosed in Japanese Patent Application Laid-Open No. 5-127074.

On the other hand, during normal photographing, the photoelectric conversion region 13α
And the output of the photoelectric conversion region 13β is added in the pixel and output.

As an exposure control for a CMOS image sensor, Japanese Patent Application Laid-Open No. 5-75931 discloses an exposure control method for a random access type image pickup device. This publication discloses an exposure control method in which an exposure time is set to be long in an area where the amount of illumination light is small.

In the CMOS image sensor used in the above-mentioned conventional focus detecting device, when displaying a photographed image at all times by an electronic viewfinder or the like, the accumulation time is controlled by a rolling shutter system. In the case of the rolling shutter system, one line of the image sensor is controlled in the same accumulation time.

[0010]

However, FIG.
As shown in FIG.
Since α and 13β receive light beams transmitted through different positions of the pupil of the photographing lens 5, the photoelectric conversion regions 13α and 13β are affected by the so-called COS power law in the peripheral region of the photographing screen.
Output imbalance occurs between them.

FIG. 18 shows an example of the output of the photoelectric conversion area α and the photoelectric conversion area β on one line of the image sensor 10 when a subject with uniform brightness is viewed. Although the output difference between the photoelectric conversion region α and the photoelectric conversion region β is small in the center region (around the optical axis), a larger output difference is generated as the position approaches the periphery. FIG. 19 shows a line image detected in the photoelectric conversion region α and the photoelectric conversion region β in the region δ in FIG. To detect the focus state of the taking lens, the image Iα
And the image Iβ must be correlated, but there is a drawback that the output difference causes the coincidence between the two images to decrease, and the focus detection accuracy to decrease.

In Japanese Patent Application Laid-Open No. 3-214133, light amount distribution information such as a decrease in peripheral light amount of a photographic lens is obtained, and a process according to the light amount distribution information is performed on a subject image signal detected by a photoelectric conversion unit. There is disclosed a focus detection device for detecting the amount of defocus of a photographing lens.

However, when the output difference between the photoelectric conversion region α and the photoelectric conversion region β of the image sensor is large, the photoelectric conversion region having a low output is required to match the level of the output image signal between the photoelectric conversion region α and the photoelectric conversion region β. When the output image signal is amplified, the noise component is also amplified, and there is a disadvantage that a highly accurate focus detection result cannot be obtained.

Further, in the case of a digital camera system in which the photographing lens is interchangeable, the output characteristics differ from those shown in FIG. 18 depending on the photographing lens mounted on the camera. As a result, the focus detection accuracy varies depending on the photographing lens. There were drawbacks.

Further, as shown in FIG. 18, even if the areas from which the image output is taken out are different even on the same line, the photoelectric conversion area α
And the photoelectric conversion region β also has a different output, so that the focus detection accuracy varies depending on the region where focus detection is performed.

The present invention has been made in view of the above-mentioned problems, and performs control so that the outputs of the photoelectric conversion regions are substantially equal even when the amount of light incident on each photoelectric conversion region of the same pixel is different. Another object of the present invention is to improve the accuracy of focus detection.

[0017]

In order to achieve the above object, an image pickup apparatus according to the present invention, which photoelectrically converts an optical image incident through a taking lens, includes a plurality of photoelectric conversion units each having two photoelectric conversion units in each pixel. A pixel, and among the photoelectric conversion units in the plurality of pixels, a photoelectric conversion unit closer to an optical axis of the imaging lens and a photoelectric conversion unit farther from the optical axis can be independently controlled. I do.

According to another aspect of the present invention, there is provided an imaging apparatus for photoelectrically converting an optical image incident through a photographic lens, comprising: a plurality of pixels each having two photoelectric conversion means in each pixel; And control means for independently controlling the photoelectric conversion means on the side closer to the optical axis of the imaging lens and the photoelectric conversion means on the side farther from the optical axis.

According to a preferred aspect of the present invention, the control unit sets the charge storage time of the photoelectric conversion unit closer to the optical axis shorter than the charge storage time of the photoelectric conversion unit farther from the optical axis. To control.

According to another preferred embodiment of the present invention, a signal obtained from a photoelectric conversion unit on the side closer to the optical axis of the imaging lens among the photoelectric conversion units of the plurality of pixels has a first signal. A signal that is output from a first amplifying unit that applies a gain and a photoelectric conversion unit that is farther from the optical axis of the imaging lens among the photoelectric conversion units of the plurality of pixels is a second signal that is larger than the first gain. And a second amplifying means for applying a gain.

In order to achieve the above object, a camera according to the present invention is equipped with any one of the above image pickup devices.

According to a preferred aspect of the present invention, the image pickup apparatus further comprises a focus detecting means for detecting a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel of the image pickup device. The control means controls the accumulation time or the first and second gains according to the position of the focus detection area on the imaging device used by the focus detection means.

Also, the control method of the image pickup apparatus according to the present invention, which photoelectrically converts an optical image incident through a photographing lens and has a plurality of pixels having two photoelectric conversion means in each pixel, comprises:
Causing the photoelectric conversion means on the side closer to the optical axis of the imaging lens among the photoelectric conversion means in the plurality of pixels to perform charge storage for a first charge storage time; Causing the photoelectric conversion unit farther from the optical axis of the imaging lens to perform charge accumulation for a second accumulation time longer than the first accumulation time, The method includes the steps of: reading out the charges accumulated in the photoelectric conversion means closer to the optical axis of the lens; and reading out the charges accumulated in the photoelectric conversion means farther from the optical axis of the imaging lens.

Further, another method of controlling an image pickup apparatus according to the present invention, which photoelectrically converts an optical image incident through a photographing lens and has a plurality of pixels each having two photoelectric conversion means in each pixel, comprises the steps of: Applying a first gain to a signal obtained from a photoelectric conversion unit on the side closer to the optical axis of the imaging lens among the photoelectric conversion units of the pixels; and applying a first gain to the signal of the imaging lens among the photoelectric conversion units of the plurality of pixels. Applying a second gain larger than the first gain to a signal output from the photoelectric conversion means on the side farther from the optical axis.

According to a preferred embodiment of the present invention, the method further comprises a focus detecting step of detecting a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel, In the setting step, the accumulation time or the first and second gains are set according to the position of the focus detection area on the imaging device used in the focus detection step.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a schematic configuration diagram of a camera according to a first embodiment having an image pickup apparatus (hereinafter, referred to as an "image sensor") according to the present invention.

In FIG. 1, the same components as those shown in FIG. 16 are denoted by the same reference numerals. Reference numeral 10 denotes an image sensor (imaging device), which is arranged on a predetermined image forming plane of a photographing lens 5 of a main body (hereinafter, referred to as a “camera main body”) 1 of a digital still camera. The camera body 1 includes a CPU 20 for controlling the entire camera, an image sensor control circuit 21 for driving and controlling the image sensor 10, an image sensor 1
0, an image processing circuit 24 for performing image processing of an image signal captured by the camera, a liquid crystal display element 9 for displaying the image processed image signal, a liquid crystal display element driving circuit 25 for driving the image signal, and a subject displayed on the liquid crystal display element 9. An eyepiece 3 for observing an image, a memory circuit 22 for recording an image captured by the image sensor 10, and an interface circuit 23 for outputting the image processed by the image processing circuit 24 to the outside of the camera. include. In the memory circuit 22,
Information unique to the photographing lens (open F value, exit window information, etc.) is also stored.

The photographing lens 5 is detachable from the camera body 1 and is shown by two lenses 5a and 5b for convenience.
The focus adjustment information sent from the CPU 20 is received by the lens CPU 50 via the electric contact 26, and the focusing state is adjusted by the photographing lens drive mechanism 51 based on the focus adjustment information. Reference numeral 53 denotes an aperture device, which is stopped down to a predetermined aperture value by an aperture drive mechanism 52. The CPU 20 also performs focus detection.

FIG. 2 is a sectional view of one pixel of the CMOS image sensor used for the image sensor 10 in the first embodiment of the present invention. In the figure, 117 is p
Type well 118 is SiO which is a gate insulating film of MOS
_Two films. 126α and 126β are surface p ₊ ,
The photoelectric conversion unit 10 includes the n-layers 125α and 125β, respectively.
1α and 101β. 120α and 120β convert the photoelectric charges accumulated in the photoelectric conversion units 101α and 101β into a floating diffusion unit (hereinafter, “FD unit”).
Call. A) a transfer gate for transfer to 121;
Reference numeral 129 denotes a color filter, reference numeral 130 denotes a microlens, and the microlens 130 is formed in a shape and position such that the pupil of the photographing lens 5 and the photoelectric conversion unit 101 of the image sensor 10 become substantially conjugate.

The photoelectric conversion units 101α and 101β
The FD portion 121 is sandwiched between two regions, an α region and a β region (hereinafter, referred to as “photoelectric conversion region α and photoelectric conversion region β”, respectively). Transfer gates 120α and 120β for transferring photocharges generated in the conversion region β to the FD unit 121, respectively.
Are formed.

At the time of normal photographing, the photoelectric charges generated in the photoelectric conversion region α and the photoelectric conversion region β are transferred to each of the transfer gates 120α and 120α.
The data is transferred to the FD unit 121 via 0β, and is controlled so as to be added. On the other hand, when detecting the focus state of the photographing lens 5, the FD from the photoelectric conversion region α and the photoelectric conversion region β
The transfer of the photocharge to the unit 121 is performed independently, and the transfer gates 120α and 120β are controlled so that the photocharge is not added.

FIG. 3 is a plan view schematically showing one line of the image sensor 10 according to the first embodiment of the present invention. The hatched central pixel on the optical axis of the photographing lens 5 in FIG. The pixel shown in FIG. In the two photoelectric conversion regions α and β in each pixel of the image sensor 10, the photoelectric conversion region closer to the pixel on the optical axis of the photographing lens 5 and the photoelectric conversion region farther from the pixel can be independently controlled. It is configured to be

That is, of the two photoelectric conversion regions in each pixel, a photoelectric conversion region β close to the center pixel of the pixel on the left side of the center pixel in the drawing and a photoelectric conversion region β close to the center pixel of the pixel on the right side of the center pixel in the drawing. The photoelectric conversion area α is controlled at the same timing. Similarly, of the two photoelectric conversion regions in each pixel, a photoelectric conversion region α farther from the center pixel on the left side of the center pixel in FIG. 3 and a photoelectric conversion region β farther from the center pixel in a pixel on the right side of the center pixel. Are controlled at the same timing.

FIG. 4 is a schematic circuit diagram of the image sensor 10 according to the first embodiment of the present invention. FIG.
1 shows a two-dimensional area sensor of 2 columns × 2 rows for simplification of the drawing, but is actually composed of several million pixels.

In FIG. 4, reference numeral 101 denotes a photoelectric conversion unit;
3 is a transfer switch MOS transistor, 104 is a reset MOS transistor, 105 is a source follower amplifier MOS transistor, and 106 is a horizontal selection switch MO.
S transistor, 107 is a load MOS of a source follower
Transistor, 108 a dark output transfer MOS transistor, 109 a light output transfer MOS transistor, 110 a dark output storage capacitor CTN, 111 a light output storage capacitor CT
S and 112 are horizontal transfer MOS transistors, 113 is a horizontal output line reset MOS transistor, and 114 is a differential amplifier. A horizontal scanning circuit 115 and a vertical scanning circuit 116 constitute the image sensor control circuit 21 shown in FIG.

In FIG. 4, the left pixel (0th pixel) on the first line corresponds to the leftmost pixel shown in FIG. 3, and the right pixel (ith pixel) on the first line is the rightmost pixel in FIG. Is equivalent to The optical axis of the taking lens 5 exists between the 0th pixel and the i-th pixel.

In each pixel, a transfer switch 103β0 and a transfer switch corresponding to the photoelectric conversion unit on the side close to the optical axis of the photographing lens 5, for example, the photoelectric conversion unit 101β0 of the 0th pixel and the photoelectric conversion unit 101αi of the i-th pixel. 103α
i is configured to be controlled by the same control pulse ΦTXα0. In each pixel, a photoelectric conversion unit on a side far from the optical axis of the photographing lens 5, for example, a photoelectric conversion unit 101α0 of the 0th pixel and a photoelectric conversion unit 101βi of the i-th pixel
Switch 103α0 and transfer switch 10 corresponding to
3βi is configured to be controlled by the same control pulse ΦTXβ0.

Next, the operation of the image sensor 10 will be described with reference to the timing chart of FIG. CMOS of the present invention
Since the camera 1 having the image sensor 10 is configured so that the image captured by the image sensor 10 can always be observed on the liquid crystal display element 9, the rolling control of the rolling shutter system is performed.

FIG. 5 is a timing chart of the 0th line when the image sensor 10 performs focus detection.
When the focus state of the photographing lens 5 is detected, a correlation operation of two images obtained from the respective outputs of the photoelectric conversion region α and the photoelectric conversion region β of each pixel is performed, and the photographing lens is calculated from the image shift amount of the two images. 5, the accumulation time of the photoelectric conversion area α and the accumulation time of the photoelectric conversion area β are set so that the outputs of the two images are substantially equal in the set focus detection area. Actually, of the two photoelectric conversion regions in one pixel, the accumulation time of the photoelectric conversion region farther from the optical axis of the imaging lens 5 is longer than that of the photoelectric conversion region closer to the optical axis of the imaging lens 5. Control pulse ΦTXα0
And ΦTXβ0 are controlled. The control pulses ΦTXα0 and ΦTXβ0 are generated by the vertical scanning circuit 116.

First, the reading of the photoelectric charges in the photoelectric conversion region on the side closer to the optical axis of the taking lens 5 is executed. Control pulse Φ
With S0 set to high, the horizontal selection switch MOS transistor 106 is turned on to select the pixel unit on the 0th line. Next, the control pulse ΦR0 is set to low to stop resetting the FD unit 121, the FD unit 121 is set to a floating state, and the gate of the source follower amplifier MOS transistor 105
After passing through between the sources, the control pulse Φ
By setting TNα to high, the dark voltage of the FD section 121 is output to the storage capacitor 110 by the source follower operation. Here, the 0th
The dark voltage of the 0th pixel portion of the line is output to the storage capacitor 110β0, and the dark voltage of the ith pixel portion is output to the storage capacitor 110αi.

Next, in order to output the photoelectric conversion region on the side near the optical axis of the photographing lens on the 0th line, the control pulse ΦT
Xα0 is set to high and transfer switch MOS transistor 1
03 is conducted, and the photo-generated carriers are transferred to the FD unit 121. When the charge from the photoelectric conversion unit 101 of the photodiode is transferred to the FD unit 121, the potential of the FD unit 121 changes according to light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD section 121 is output to the storage capacitor 111 with the control pulse ΦTSα being high. Here, the light output of the 0th pixel portion on the 0th line is equal to the storage capacity 111.
β0, and the light output of the i-th pixel unit is
output to αi. At this point, the dark output and the light output of the photoelectric conversion area of the pixel on the 0th line, which is closer to the optical axis of the taking lens, are stored in storage capacitors 110 and 111, respectively.

Next, the accumulation control of the photoelectric conversion area closer to the optical axis of the photographing lens 5 is controlled to be shorter by Δt than the accumulation time of the photoelectric conversion area farther from the optical axis of the photographing lens. For this reason, after the control pulse ΦTXα0 becomes high at time Δt, the control pulse ΦTXα0 becomes high again to turn on the transfer switch MOS transistor 103, and the photocharge generated and accumulated at time Δt is accumulated in the FD unit 121.
Transfer to At this time, if the control pulse ΦR0 is set to high, the charge of the FD section 121 disappears. Further, when the transfer pulse MOS transistor 103 is closed by setting the control pulse ΦTXα0 to low, the re-accumulation of the photoelectric charge is started in the photoelectric conversion region on the side closer to the optical axis of the taking lens, and the light is accumulated until the photoelectric charge is read out again. Charge is stored.

Subsequently, the reading of the photoelectric charges in the photoelectric conversion region far from the optical axis of the taking lens is executed. The control pulse φS0 is set high to turn on the horizontal selection switch MOS transistor 106, and the pixel unit on the 0th line is selected. Next, the control pulse ΦR0 is set to low to stop resetting of the FD unit 121, the FD unit 121 is set to a floating state, the gate-source of the source follower amplifier MOS transistor 105 is set to a through state, and after a predetermined time, the control pulse ΦTNβ is set to high. , The dark voltage of the FD section 121 is output to the storage capacitor 110 by the source follower operation. Here, the dark voltage of the 0th pixel portion on the 0th line is equal to the storage capacitance 110
α0, and the dark voltage of the i-th pixel portion is
output to βi.

Next, in order to output the photoelectric conversion region farther from the optical axis of the photographing lens of each pixel on the 0th line, the control pulse ΦTXβ0 is set high to turn on the transfer switch MOS transistor 103, and the photocharge is converted to FD. Transfer to the unit 121. The charge from the photoelectric conversion unit 101 of the photodiode is transferred to the FD unit 121 so that the FD unit 121
Will change according to the light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD section 121 is output to the storage capacitor 111 with the control pulse ΦTSβ being high. Here, the light output of the 0th pixel portion on the 0th line is equal to the storage capacity 111.
α0, and the light output of the i-th pixel unit is
output to βi. At this point, the dark output and the light output of the photoelectric conversion area of the pixel on the 0th line, which is farther from the optical axis of the taking lens, are stored in storage capacitors 110 and 111, respectively.
Set the control pulse ΦTXβ0 to low and set the transfer switch MOS
When the transistor 103 is closed, the accumulation of the photoelectric charge is started in the photoelectric conversion region farther from the optical axis of the taking lens, and the photoelectric charge is accumulated until the reading of the photoelectric charge is performed again.

The photocharge generated by the photoelectric conversion unit 101 is first read out from the photoelectric conversion region on the side closer to the optical axis of the photographing lens 5 to the storage capacitor 111 in each pixel, and then is read to the optical axis of the photographing lens 5. The control is performed so that reading is performed from the photoelectric conversion region on the far side to the storage capacitor 111, but the output from the image sensor 10 to the outside is not subjected to the rearrangement processing of the subsequent signals. The horizontal scanning circuit 115 controls so that the division direction of the region is sequentially output from the photoelectric conversion region in the same direction.

The output from the image sensor 10 to the outside is
The control pulse ΦHC is temporarily set high to turn on the horizontal output line reset MOS transistor 113 to reset the horizontal output line, and output to the horizontal output line in the horizontal transfer period by the scanning timing signal to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115. Is done. Horizontal scanning circuit 115
Generates a scanning timing signal so as to first output the optical output of the photoelectric conversion region α among the photoelectric conversion regions of each pixel. As a result, the storage capacity 1
The storage capacity up to 11αi is output to the outside of the image sensor. Subsequently, the horizontal scanning circuit 115 generates a scanning timing signal so as to output the optical output of the photoelectric conversion region β among the photoelectric conversion regions of each pixel. As a result, the storage capacitors from the storage capacitors 111β0 to 111βi are sequentially output to the outside of the image sensor 10. At this time, the storage capacitors 110 and 111 are
, A signal having a good S / N ratio from which random noise and fixed pattern noise of pixels are removed can be obtained.

The output from the image sensor 10 is shaped as a focus detection image signal by the CPU 20 that performs focus detection processing.

FIG. 6 shows the outputs of the photoelectric conversion areas α and β of each pixel on the 0th line when an object of uniform brightness is photographed. Since an accumulation time difference of Δt0 is provided between the photoelectric conversion region closer to the optical axis of the photographing lens and the photoelectric conversion region farther from the optical axis, the outputs from the respective photoelectric conversion regions in the focus detection regions δ1 and δ2 in the drawing are almost equal. It has become.

FIG. 7 shows an example of a focus detection image detected in the focus detection areas δ1 and δ2 of FIG. 6, for example, when the subject is a single line. Image signal I for focus detection
The outputs of α and Iβ are almost the same. As a result, the degree of correlation between the two image signals increases, and it is possible to perform highly accurate focus detection.

When the focus state of the photographing lens 5 is accurately detected by the CPU 20 based on the focus detection signal output from the image sensor 10, the CPU 20 controls the electric current provided between the camera body 1 and the photographing lens 5. Defocus information of the photographing lens 5 is transmitted to the lens CPU through the contact 26.
Send to 50. The lens CPU 50 is the C of the camera body 1
The defocus information received from the PU 20 is converted into a photographing lens driving amount and transmitted by the lens driving mechanism 51 to adjust the focus state of the photographing lens 5.

When the focus detection is to be performed in a line different from the 0th line and in a region different from the focus detection regions δ1 and δ2 of FIG. 6, the side closer to the optical axis of the photographing lens of each pixel of the image sensor 10 is used. Since the difference in the amount of received light differs between the photoelectric conversion region and the photoelectric conversion region on the far side, different accumulation time control is required.

For example, as shown in FIG.
When focus detection is to be performed in focus detection areas δ3 and δ4 outside of the focus detection areas δ1 and δ2 with respect to the optical axis of, the photoelectric conversion area closer to the optical axis of the taking lens and the photoelectric conversion area farther from the optical axis Because the difference in the amount of received light with
The control is performed such that the accumulation time of the photoelectric conversion region farther from the photoelectric conversion region closer to the optical axis of the photographing lens 5 is longer.

FIG. 9 shows the focus detection areas δ3 and δ4 of FIG.
9 is a timing chart of the j-th line for making the output signals of the photoelectric conversion region closer to the optical axis of the taking lens 5 and the output signal of the photoelectric conversion region farther away from each other substantially the same. The circuit configuration of the image sensor at this time is the same as that in FIG.

9 differs from the timing chart of the 0th line in FIG. 5 in the time of each control pulse.
Since the focus detection area of the j-th line is set further outward with respect to the optical axis of the photographing lens 5, the accumulation time of the photoelectric conversion area closer to the optical axis of the photographing lens and the photoelectric conversion area farther from the optical axis of the photographing lens 5 The ratio is (t0−Δt0) / t0> (tj−Δtj) / t
j

The vertical scanning circuit 116 controls each control pulse so as to satisfy the following. As is apparent from FIG. 16, the amount of light received in the photoelectric conversion region closer to the optical axis and the photoelectric conversion region farther from the optical axis of the photographing lens depends on the open F-number and the exit window of the photographing lens 5 mounted on the camera body 1. The difference changes. FIG. 10 is a flowchart for setting the accumulation time ratio of each photoelectric conversion area of the image sensor 10 by the photographing lens mounted on the camera body 1. Hereinafter, FIG.
This will be described with reference to the flowchart of FIG.

The CPU 20 of the camera body 1 attempts to communicate with the lens CPU 50 via the electric contact 26 with the taking lens 5 (step S201). Camera 1 with shooting lens 5
Is mounted and can communicate with the lens CPU 50 (YES in step S201), the camera CPU 20 checks the type (ID) of the mounted photographing lens 5 (step S202). When the type of the mounted photographing lens is confirmed, the CPU 20 confirms the unique information such as the opening F value of the photographing lens and the exit window information stored in the memory circuit 22 (step S203). Further, the camera CPU 20 uses the information such as the open F-number of the mounted photographing lens 5, the position of the exit window, the diameter of the exit window, and the position of the focus detection area on the image sensor 10 to obtain an image sensor used for focus detection. The position of the center of gravity of the light beam received by each of the photoelectric conversion regions 10 on the pupil of the photographing lens 5 is calculated (step S2).
04). The camera CPU 20 further sets a straight line connecting the position of the center of gravity of the received light beam received by the photoelectric conversion regions α and β on the pupil of the photographing lens 5 and the photoelectric conversion regions α and β, respectively,
The angles θα and θβ between the image sensor 10 and the perpendicular are calculated (step S204) (see FIG. 16). Here, the received light amount ratio between the photoelectric conversion region α and the photoelectric conversion region β is
Almost COS4 (θα): COS4 (θβ)

Is as follows. For example, when the photoelectric conversion region closer to the optical axis of the photographing lens is the photoelectric conversion region α and the photoelectric conversion region farther from the optical axis of the photographing lens is the photoelectric conversion region β, the image shown in the timing chart of FIG. When the accumulation control of the sensor 10 is performed, the CPU 20

(Tj−Δtj) / tj = COS4 (θ
β) / COS4 (θα) Image sensor 1 with the storage time ratio set as above
When the accumulation time of 0 is controlled, the output levels of the two focus detection image signals in the predetermined focus detection area become substantially equal, and the focus detection using the two focus detection image signals has a highly accurate result. Will be obtained.

Here, an example is shown in which the unique information such as the opening F-number of the taking lens and the exit window information is stored in the memory circuit 22 provided in the camera body 1.
A system for storing data in a memory circuit associated with 0 may be used.

FIG. 11 is a timing chart of the 0th line when the image sensor 10 performs normal imaging. At the time of normal imaging, photocharges generated in the photoelectric conversion regions α and β are simultaneously transferred to the FD unit 121, added, and output outside the image sensor 10.

In FIG. 11, the control pulse .PHI.S0 is set high and the horizontal selection switch MOS transistor 106 is turned on by the timing output from the vertical scanning circuit 116 to select the pixel portion on the 0th line. Next, the control pulse ΦR0 is set to low to stop resetting the FD unit 121, and the FD
After the section 121 is set in a floating state and the gate-source of the source follower amplifier MOS transistor 105 is made through, the control pulse ΦTNβ is set high after a predetermined time, and the dark voltage of the FD section 121 is stored in the storage capacitor 110α or 110β by the source follower operation. Is output to the conductive one.

Next, in order to output the two photoelectric conversion areas α and β of each pixel on the 0th line, a control pulse ΦTXα
0 and ΦTXβ0 are set high, and the transfer switch MOS transistors 103α and 103β are turned on. At this time, the photoelectric charge generated in the photoelectric conversion units 101α and 101β is FD
It is transferred to the unit 121. By transferring charges from the photoelectric conversion units 101α and 101β of the photodiode to the FD unit 121, the potential of the FD unit 121 changes according to light. At this time, the source follower amplifier MOS
Since the transistor 105 is in a floating state,
The potential of the FD section 121 is output to the conductive one of the storage capacitors 110α and 111β with the control pulse ΦTSβ being high. At this time, the dark output and the light output of each pixel on the 0th line are the storage capacitors 110α or 110β and 111
will be stored in α or 111β, respectively. Further, the control pulse ΦHC is temporarily set high to turn on the horizontal output line reset MOS transistor 113 to reset the horizontal output line, and the horizontal output line is reset by the scanning timing signal to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115 during the horizontal transfer period. A dark output and a light output of the pixel are output. At this time, since the differential output Vout is obtained by the differential amplifier 114 for the electric charges stored in the storage capacitors 110α and 111α or 110β and 111β, the S / N ratio in which random noise and fixed pattern noise of pixels are removed is good. A signal is obtained.

Subsequently, the monitor output of each pixel is detected based on a scanning timing signal to the horizontal transfer MOS transistor of each pixel by the horizontal scanning circuit 115. Further, the vertical scanning circuit 116 similarly outputs all pixels of the image sensor 10 by outputting the next line.

In the first embodiment, an example has been described in which, during normal imaging, control is performed so that the accumulation times of the two photoelectric conversion regions of each pixel are the same, but as shown in the timing chart of FIG. Depending on the lens attached to the camera, the accumulation time of the photoelectric conversion area closer to the optical axis of the photographic lens and the photoelectric conversion area farther to the optical axis of the photographic lens are controlled so that they are added in each pixel. It is also effective to minimize the output imbalance due to a decrease in the amount of light at a position distant from the optical axis.

<Second Embodiment> Next, a second embodiment of the present invention will be described. In the first embodiment, the signal difference between the image signals Iα and Iβ shown in FIG.
Although the adjustment is made by making the accumulation time in the photoelectric conversion region α and the photoelectric conversion region β different, in the second embodiment, the adjustment is made by multiplying the obtained image signals Iα and Iβ by different gains.

Note that the schematic configuration of the camera according to the second embodiment is the same as that described with reference to FIG. 1 in the first embodiment, and a description thereof will be omitted. FIG. 13 is a circuit configuration diagram of the image sensor 10 according to the second embodiment of the present invention. Although FIG. 13 shows a two-dimensional area sensor of 2 columns × 2 rows for simplification of the drawing,
Actually, it is composed of several million pixels. In FIG. 13, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

The configuration shown in FIG. 13 differs from that of FIG. 4 in that there are two horizontal output systems.
4H is a differential amplifier. Unlike the configuration shown in FIG. 4, the photoelectric conversion region α of each pixel is controlled by ΦTXαi, and the photoelectric conversion region β is controlled by ΦTXβi.
That is, the wiring is as shown in FIG. 115 ′ is a horizontal scanning circuit 115 ′ and a vertical scanning circuit 116 is
The image sensor control circuit 21 shown in FIG.

In FIG. 13, the left pixel (0th pixel) on the first line corresponds to the leftmost pixel shown in FIG. 17, and the right pixel (ith pixel) on the first line is the rightmost pixel in FIG. Is equivalent to The optical axis of the taking lens 5 exists between the 0th pixel and the i-th pixel.

In each pixel, the light output of the photoelectric conversion unit on the side closer to the optical axis of the photographing lens 5, for example, the photoelectric conversion unit 101β0 of the 0th pixel and the photoelectric conversion unit 101αi of the i-th pixel has a low-gain differential output. It is configured to be output via the amplifier 114L. Further, in each pixel, a photoelectric conversion unit farther from the optical axis of the photographing lens 5, for example, a photoelectric conversion unit 101α0 of the 0th pixel and a photoelectric conversion unit 101 of the i-th pixel
βi is configured to be output by the high gain differential amplifier 114H.

Next, the operation of the image sensor 10 will be described with reference to the timing chart of FIG. CMO of the present invention
Since the camera 1 having the S image sensor 10 is configured so that an image captured by the image sensor 10 can always be observed on the liquid crystal display element 9, the accumulation control of the rolling shutter system is performed.

FIG. 14 is a timing chart of the 0th line when the image sensor 10 performs focus detection. When the focus state of the photographing lens 5 is detected, a correlation operation of two images obtained from the respective outputs of the photoelectric conversion region α and the photoelectric conversion region β of each pixel is performed, and the photographing lens is calculated from the image shift amount of the two images. 5 focus state is detected,
The gains of the differential amplifiers 114L and 114H are set so that the outputs of the two images are substantially equal in the set focus detection area. In fact, of the two photoelectric conversion regions in one pixel, the photoelectric conversion region on the side farther from the optical axis of the imaging lens 5 than the gain given to the signal obtained from the photoelectric conversion region on the side closer to the optical axis of the imaging lens 5. It is set so that the gain of the conversion area becomes high.

First, of the photoelectric conversion region divided into two for each pixel, reading of the photoelectric charge in the same direction, for example, the photoelectric conversion region α is executed. Control pulse ΦS0
Is set to high, the horizontal selection switch MOS transistor 10
6 is turned on to select the pixel unit on the 0th line. Next, the control pulse ΦR0 is set to low, the reset of the FD unit 121 is stopped, the FD unit 121 is set in a floating state, the gate-source of the source follower amplifier MOS transistor 105 is set to a through state, and after a predetermined time, the control pulse ΦTNα is set to high. The dark voltage of the FD section 121 is output to the storage capacitor 110α by the source follower operation.

Next, in order to output the photoelectric conversion area α,
Set the control pulse ΦTXα0 high and set the transfer switch MOS
The transistor 103α is turned on to transfer the photo-generated carriers of the photoelectric conversion unit 101α to the FD unit 121. The charge from the photoelectric conversion unit 101α of the photodiode is
, The potential of the FD section 121 changes according to the light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD section 121 is output to the storage capacitor 111α with the control pulse ΦTSα being high. At this time, the dark output and light output of the photoelectric conversion region α are respectively equal to the storage capacitance 110α.
And 111α. When the transfer switch MOS transistor 103α is closed by setting the control pulse ΦTXα0 to low, the accumulation of the photoelectric charge starts in the photoelectric conversion region α, and the photoelectric charge is accumulated until the photoelectric charge is read out again.

Subsequently, the reading of the photoelectric charges in the photoelectric conversion region β is executed. The control pulse φS0 is set high to turn on the horizontal selection switch MOS transistor 106 to select the pixel unit on the 0th line. Next, the control pulse ΦR0 is set to low, the reset of the FD unit 121 is stopped, the FD unit 121 is set in a floating state, and the source follower amplifier MOS
After passing through between the gate and the source of the transistor 105, the control pulse ΦTNβ is set high after a predetermined time, and the dark voltage of the FD section 121 is stored in the storage capacitor 110 by the source follower operation.
Output to β.

Next, in order to output the photoelectric conversion region β of each pixel on the 0th line, the control pulse ΦTXβ0 is set high to turn on the transfer switch MOS transistor 103β,
The photoelectric charge of the photoelectric conversion unit 101β is transferred to the FD unit 121. The charge from the photoelectric conversion unit 101β of the photodiode is transferred to the FD unit 121 so that the FD unit 121
Will change according to the light. At this time, since the source follower amplifier MOS transistor 105 is in a floating state, the potential of the FD section 121 is output to the storage capacitor 111β with the control pulse ΦTSβ set to high. At this time, the dark output and the optical output of the photoelectric conversion region of the pixel on the 0th line, which is farther from the optical axis of the taking lens, are stored in storage capacitors 110β and 111β, respectively. Control pulse ΦTX
When β0 is low, the transfer switch MOS transistor 10
When 3β is closed, the accumulation of the photoelectric charge in the photoelectric conversion region β is started, and the photoelectric charge is accumulated until the reading of the photoelectric charge is performed again.

The output from the image sensor to the outside is made by setting the control pulse ΦHC temporarily high to reset the horizontal output line reset MO.
The S-transistor 113 is turned on to reset the horizontal output line, and is output to the horizontal output line by a scanning timing signal to the horizontal transfer MOS transistor 112 of the horizontal scanning circuit 115 during the horizontal transfer period.

Here, the storage capacity from the photoelectric conversion area on the side closer to the optical axis of the photographing lens 5, for example, the storage capacity 111β0 of the photoelectric conversion unit 101β0 of the 0th pixel and the storage capacity 111αi of the photoelectric conversion unit 101αi of the i-th pixel. Are configured to be output by the low gain differential amplifier 114L. On the other hand, the storage capacity from the photoelectric conversion area farther from the optical axis of the photographing lens 5, for example, the photoelectric conversion unit 101α of the 0th pixel
0 storage capacitor 111α0 and the photoelectric conversion unit 10 of the i-th pixel.
The 1βi storage capacitor 111βi is configured to be output by the high gain differential amplifier 114H.

Further, the horizontal scanning circuit 115 first generates a scanning timing signal so as to output the optical output of the photoelectric conversion region α among the photoelectric conversion regions of each pixel. As a result, the storage capacitors from the storage capacitors 111α0 to 111αi are sequentially output to the outside of the image sensor 10. Subsequently, the horizontal scanning circuit 115 generates a scanning timing signal so as to output the optical output of the photoelectric conversion region β among the photoelectric conversion regions of each pixel. As a result, the storage capacitors from the storage capacitors 111β0 to 111βi are sequentially output to the outside of the image sensor 10. At this time,
Storage capacity 110α and 111α, or storage capacity 110β
And 111β are obtained as differential output VoutL or VoutH by the differential amplifier 114L or 114H, so that a signal having a good S / N ratio from which random noise and fixed pattern noise of pixels are removed can be obtained.

The output from the image sensor 10 is shaped into a focus detection image signal by a CPU that performs focus detection.
Since the output gain of the photoelectric conversion region farther from the photoelectric conversion region closer to the optical axis of the photographing lens 5 is set higher, the output from each photoelectric conversion region is substantially equal. As a result, the degree of correlation between the two image signals Iα and Iβ used for focus detection is increased, and highly accurate focus detection can be performed.

When the focus state of the photographing lens 5 is accurately detected by the CPU 20 based on the focus detection signal output from the image sensor 10, the CPU 20 turns off the electric current provided between the camera body 1 and the photographing lens 5. Defocus information of the photographing lens 5 is transmitted to the lens CPU through the contact 26.
Send to 50. The lens CPU 50 is the C of the camera body 1
The defocus information received from the PU 20 is converted into a photographing lens driving amount and transmitted by the lens driving mechanism 51 to adjust the focus state of the photographing lens 5.

As is clear from FIG. 16, the photoelectric conversion area closer to the optical axis of the imaging lens and the photoelectric conversion area farther from the optical axis of the imaging lens depend on the open F-number of the imaging lens 5 mounted on the camera body 1 and the exit window. Changes in the amount of received light. FIG. 15 is a flowchart for setting the gain ratio (GL: GH) of the differential amplifiers 114L and 114H by the photographing lens mounted on the camera body 1. Hereinafter, description will be made with reference to the flowchart of FIG.

The CPU 20 of the camera body 1 tries to communicate with the lens CPU 50 via the electric contact 26 with the taking lens 5 (step S201). Camera 1 with shooting lens 5
Is mounted and can communicate with the lens CPU 50 (YES in step S201), the camera CPU 20 checks the type (ID) of the mounted photographing lens 5 (step S202). When the type of the mounted photographing lens is confirmed, the CPU 20 confirms the unique information such as the opening F value of the photographing lens and the exit window information stored in the memory circuit 22 (step S203). Further, the camera CPU 20 uses the information such as the open F-number of the mounted photographing lens 5, the position of the exit window, the diameter of the exit window, and the position of the focus detection area on the image sensor 10 to obtain an image sensor used for focus detection. The position of the center of gravity of the light beam received by each of the photoelectric conversion regions 10 on the pupil of the photographing lens 5 is calculated (step S2).
04). The camera CPU 20 further sets a straight line connecting the position of the center of gravity of the received light beam received by the photoelectric conversion regions α and β on the pupil of the photographing lens 5 and the photoelectric conversion regions α and β, respectively,
The angles θα and θβ between the image sensor 10 and the perpendicular are calculated (step S204) (see FIG. 16). Here, the received light amount ratio between the photoelectric conversion region α and the photoelectric conversion region β is
Almost COS4 (θα): COS4 (θβ)

Is obtained. For example, when the photoelectric conversion region closer to the optical axis of the photographing lens is the photoelectric conversion region α and the photoelectric conversion region farther from the optical axis of the photographing lens is the photoelectric conversion region β, the image sensor shown in the timing chart of FIG. When the accumulation control is performed, the CPU 20 determines that GL / GH = COS4 (θβ) / COS4 (θα)

The gain ratio is set so as to satisfy (S306). With the gain ratios set as described above, the differential amplifiers 114L and 114H of the image sensor 10 are used.
Is controlled, the output levels of the two focus detection image signals in a predetermined focus detection area become substantially equal,
Focus detection using two focus detection image signals can provide highly accurate results.

Here, an example is shown in which the unique information such as the opening F-number of the photographing lens and the exit window information is stored in the memory circuit 22 provided in the camera body 1.
It may be stored in a system that stores data in a memory circuit associated with 0.

In the second embodiment, the timing chart and the drive control for capturing a normal image are as follows.
It is similar to that described above with reference to FIG.

[0088]

Other Embodiments In the first and second embodiments, an example has been shown in which the photoelectric conversion region in one pixel is divided in the horizontal direction to control the accumulation time of each photoelectric conversion region. The middle photoelectric conversion region may be divided in the vertical direction, and even in this case, the photoelectric conversion region on the side closer to the optical axis of the taking lens and the photoelectric conversion region on the far side are configured to be independently controllable. It is desirable.

In the first and second embodiments, an example in which the image pickup device (image sensor) is arranged on the primary image forming surface of the photographing lens has been described. It goes without saying that a configuration arranged on a surface is also effective.

In the first and second embodiments, the case where the image sensor 10 is a CMOS image sensor has been described. However, the present invention is not limited to this, and may be, for example, a CCD image sensor. .

The software configuration and the hardware configuration of the above embodiment can be replaced as appropriate.

The present invention may be implemented by combining the above embodiments or the technical elements as needed.

[0093] The present invention also relates to the present invention,
Alternatively, the whole or a part of the configuration of the embodiment may be one that forms one device, or may be combined with another device, or may be one that constitutes a device. There may be.

The present invention can be applied to various types of imaging devices, such as video cameras, video still cameras, cameras with interchangeable photographing lenses, single-lens reflex cameras, lens shutter cameras, surveillance cameras, and the like. The present invention can be applied to a device, a method, a medium such as a computer-readable storage medium, and components constituting these.

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. Or CPU and MPU) read and execute the program code stored in the storage medium,
It goes without saying that this is achieved. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.
In addition, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also based on the instructions of the program code,
The operating system (OS) running on the computer performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included. Here, as a storage medium for storing the program code, for example, a floppy (registered trademark) disk, a hard disk, a ROM,
RAM, magnetic tape, nonvolatile memory card, CD-
ROMs, CD-Rs, DVDs, optical disks, magneto-optical disks, MOs, and the like are conceivable.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

[0097]

As described above, according to the present invention,
Even when the amount of light incident on each photoelectric conversion region of the same pixel is different, the output of each photoelectric conversion region is controlled so as to be substantially equal, so that the accuracy of focus detection can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a camera according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of one pixel of the image sensor according to the embodiment of the present invention.

FIG. 3 is a schematic plan view showing one line of the image sensor according to the first embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of the image sensor according to the first embodiment of the present invention.

FIG. 5 is a driving timing chart of the image sensor at the time of focus detection according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating an output of the image sensor according to the first embodiment of the present invention.

FIG. 7 is a diagram illustrating an output image of the image sensor according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating an output of the image sensor according to the first embodiment of the present invention.

FIG. 9 is a drive timing chart of the image sensor during focus detection according to the first embodiment of the present invention.

FIG. 10 is a flowchart of an accumulation time ratio determination process for focus detection according to the first embodiment of the present invention.

FIG. 11 is a timing chart illustrating an example of image sensor driving during normal shooting according to the first embodiment of the present invention.

FIG. 12 is a timing chart illustrating another example of image sensor driving during normal shooting according to the first embodiment of the present invention.

FIG. 13 is a circuit configuration diagram of an image sensor according to a second embodiment of the present invention.

FIG. 14 is a driving timing chart of an image sensor at the time of focus detection according to the second embodiment of the present invention.

FIG. 15 is a flowchart of a gain ratio determination process for focus detection according to the second embodiment of the present invention.

FIG. 16 is a diagram illustrating the principle of a conventional pupil division type focus detection method.

FIG. 17 is a schematic plan view showing one line of a conventional image sensor.

FIG. 18 is a diagram illustrating an output of a conventional image sensor.

FIG. 19 is a diagram illustrating an output image of an image sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 3 Eyepiece 5 Shooting lens 9 Liquid crystal display element 10 Image sensor 20 CPU 21 Image sensor control circuit 22 Memory circuit 23 Interface circuit 24 Image processing circuit 25 Liquid crystal display element drive circuit 26 Electric contact 50 Lens CPU 51 Photographing Lens drive mechanism 52 Aperture drive mechanism 53 Aperture device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/232 H01L 27/14 B 5/335 G02B 7/11 C // H04N 101: 00 G03B 3/00 A F term (Ref.) GY31 GZ26 HX17

Claims (29)

[Claims] 1. An image pickup apparatus for photoelectrically converting an optical image incident through a photographing lens, comprising: a plurality of pixels each having two photoelectric conversion units; An imaging apparatus characterized in that, of the means, the photoelectric conversion means on the side closer to the optical axis of the imaging lens and the photoelectric conversion means on the side farther from the optical axis can be independently controlled. 2. An imaging apparatus for photoelectrically converting an optical image incident through a photographic lens, comprising: a plurality of pixels each having two photoelectric conversion units; and a photoelectric conversion unit in each of the plurality of pixels. An imaging apparatus, comprising: a photoelectric conversion unit on the side closer to the optical axis of the imaging lens and a control unit for independently controlling the photoelectric conversion unit on the side farther from the optical axis. 3. The control means controls the charge accumulation time of the photoelectric conversion means closer to the optical axis to be shorter than the charge accumulation time of the photoelectric conversion means farther from the optical axis. The imaging device according to claim 2. 4. The imaging apparatus according to claim 3, further comprising storage means for storing a predetermined charge accumulation time. 5. The imaging apparatus according to claim 3, wherein the imaging lens is detachable, and the control unit controls a charge accumulation time according to a connected imaging lens. 6. The position of the center of gravity of the light beam received by the two photoelectric conversion regions of each pixel on the pupil of the photographing lens, the photoelectric conversion region closer to the optical axis and the photoelectric conversion region farther from the optical axis. Assuming that the angles formed by the straight lines connecting the respective lines and the perpendicular of the imaging device are θ1 and θ2, respectively, the accumulation period of the photoelectric conversion region closer to the optical axis is t1, and the accumulation time of the photoelectric conversion region farther from the optical axis is t2. 6. The imaging apparatus according to claim 5, wherein the control unit sets the accumulation time so as to satisfy t1 / t2 = COS4 (θ1) / COS4 (θ2). 7. A first amplifying means for applying a first gain to a signal obtained from a photoelectric conversion means on a side closer to an optical axis of the imaging lens among the photoelectric conversion means of the plurality of pixels; Of the photoelectric conversion means of the pixel, the signal output from the photoelectric conversion means on the side far from the optical axis of the imaging lens,
3. The imaging apparatus according to claim 2, further comprising: a second amplifying unit that applies a second gain larger than the first gain. 8. The imaging apparatus according to claim 4, further comprising storage means for holding predetermined first and second gains. 9. The photographing lens according to claim 7, wherein the photographing lens is detachable, and the control unit controls the first and second gains according to a photographing lens connected to the photographing lens. Imaging device. 10. The position of the center of gravity of the received light beam received by the two photoelectric conversion regions of each pixel on the pupil of the photographing lens, the photoelectric conversion region closer to the optical axis and the photoelectric conversion region farther from the optical axis. Assuming that the angles formed by the straight lines connecting the respective lines and the perpendicular line of the imaging apparatus are θ1 and θ2, the first gain is G1, and the second gain is G2, the control means: G1 / G2 = COS4 (θ1) The imaging apparatus according to claim 9, wherein the first and second gains are set so as to satisfy / COS4 (θ2). 11. The control device according to claim 5, wherein the control unit controls based on lens opening F-number and exit window information of the connected photographing lens. Imaging device. 12. A camera equipped with the imaging device according to claim 1. 13. The photographing lens according to claim 5, wherein the detecting means is detachable from the photographing lens, the detecting means detects the detached state of the photographing lens, and the acquiring means acquires information on the connected photographing lens. A camera equipped with the imaging device according to the above. 14. The apparatus according to claim 1, further comprising a focus detection unit configured to detect a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel of the imaging device, wherein the control unit controls the focus detection unit. 14. The camera according to claim 13, wherein the accumulation time is controlled according to the position of the focus detection area on the imaging device used in the step (c). 15. The photographing lens according to claim 9, wherein the detecting means is detachable from the photographing lens, detects a detaching state of the photographing lens, and obtains information on the connected photographing lens. A camera equipped with the imaging device described in the above. 16. The apparatus according to claim 16, further comprising a focus detection unit configured to detect a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel of the imaging device, wherein the control unit controls the focus detection unit. 16. The camera according to claim 15, wherein the first and second gains are controlled in accordance with a position of a focus detection area on the imaging device used in the step (c). 17. A method for controlling an image pickup apparatus which photoelectrically converts an optical image incident through a photographing lens and has a plurality of pixels having two photoelectric conversion units in each pixel, the method comprising: Causing the photoelectric conversion means on the side closer to the optical axis of the imaging lens to perform charge storage for a first charge storage time, among the photoelectric conversion means; Causing the photoelectric conversion means on the side farther from the optical axis of the imaging lens to perform charge accumulation for a second accumulation time longer than the first accumulation time; A step of reading out the charge stored in the photoelectric conversion means on the side, and a step of reading out the charge stored in the photoelectric conversion means on the side far from the optical axis of the imaging lens. 18. The photographing lens is detachable,
18. The control method according to claim 17, further comprising a setting step of setting the first and second charge accumulation times according to the connected photographing lens. 19. The position of the center of gravity of the light beam received by the two photoelectric conversion regions of each pixel on the pupil of the taking lens, the photoelectric conversion region closer to the optical axis and the photoelectric conversion region farther from the optical axis. Assuming that the angles between the straight lines connecting the respective lines and the perpendicular line of the imaging device are θ1 and θ2, respectively, the accumulation period of the photoelectric conversion region closer to the optical axis is t1, and the accumulation time of the photoelectric conversion region farther from the optical axis is t2. 19. The control method according to claim 18, wherein in the setting step, the accumulation time is set so as to satisfy t1 / t2 = COS4 (θ1) / COS4 (θ2). 20. The control method according to claim 18, further comprising: a detecting step of detecting a detached state of the photographing lens; and an acquiring step of acquiring information of a connected photographing lens. 21. A focus detection step of detecting a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel, wherein the setting step includes imaging used in the focus detection step. 21. The control method according to claim 20, wherein the accumulation time is set according to the position of the focus detection area on the device. 22. A method of controlling an image pickup apparatus having a plurality of pixels each having two photoelectric conversion means in each pixel for photoelectrically converting an optical image incident through a photographing lens, comprising: Applying a first gain to a signal obtained from a photoelectric conversion unit on the side closer to the optical axis of the imaging lens among the conversion units; and from the optical axis of the imaging lens among the photoelectric conversion units of the plurality of pixels. In the signal output from the photoelectric conversion means on the far side,
Applying a second gain greater than the first gain. 23. The photographing lens is detachable,
23. The control method according to claim 22, further comprising a setting step of setting the first and second gains according to the connected photographing lens. 24. The position of the center of gravity of the light beam received by the two photoelectric conversion regions of each pixel on the pupil of the taking lens, the photoelectric conversion region closer to the optical axis and the photoelectric conversion region farther from the optical axis. Assuming that the angles formed by the straight lines connecting the respective lines and the perpendicular to the imaging device are θ1 and θ2, the first gain is G1, and the second gain is G2, in the setting step, G1 / G2 = COS4 (θ1) 24. The control method according to claim 23, wherein the first and second gains are set so as to satisfy / COS4 (θ2). 25. The control method according to claim 23, further comprising: a detecting step of detecting a detached state of the photographing lens; and an acquiring step of acquiring information of a connected photographing lens. 26. The imaging apparatus according to claim 26, further comprising: a focus detection step of detecting a focus state of the photographing lens based on signals output from two photoelectric conversion regions of each pixel. 26. The control method according to claim 25, wherein the first and second gains are set according to the position of the focus detection area on the device. 27. The image forming apparatus according to claim 18, wherein the setting step is performed based on lens opening F-number and exit window information of the connected photographing lens.
The control method according to any one of the above. 28. A program executable by an information processing apparatus having a program code for realizing the control method according to claim 17. Description: 29. A storage medium storing the program according to claim 28.