JP2001177756A - Image pickup device and camera system provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of an image pickup device and a camera system. SOLUTION: A focus is adjusted on the basis of output signals from focus adjustment areas 61', 62', 63', 64', 65', 66' and 67 being parts of a photographing area of an image pickup element 400 and consisting of pixels without defect in the photographing area of the image pickup element 400.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup apparatus mounted on a digital still camera, a video camera, and the like, and a camera system including the same.

[0002]

2. Description of the Related Art Conventionally, a camera system having a solid-state imaging device such as a digital still camera and a video camera captures a still image and a moving image with one or more imaging devices and stores the image in a holding unit such as a memory. I was recording. The reason why imaging and recording can be performed by one or more imaging elements is that the imaging elements have been improved in resolution, reduced in size, and reduced in price.

In these camera systems, a part of the imaging area of the imaging device may be used for focus adjustment.
That is, a large number of the imaging regions of the imaging element are used for imaging, but a small number are used for focus adjustment.

FIG. 10 is a plan view of an image pickup area of a conventional image pickup device. As illustrated in FIG. 10, the imaging area includes an area in which a part of the pixel is used for focus adjustment (hereinafter, referred to as “focus adjustment area”), and the focus adjustment area is set at positions 161 to 167. Is shown. This setting position 1
The imaging areas other than 61 to 167 are used exclusively for imaging.

Here, a set position 161 of the focus adjustment area is set.
To 167 are arranged at, for example, a plurality of positions at equal intervals so that the focus can be adjusted even when the subject is not located at the center of the image sensor.

[0006]

However, for example, a defect may occur in a pixel constituting an image sensor in a manufacturing process or the like. Such defects include, for example, white spots where the output signal of the pixel is large, black spots where the output signal is small, poor linearity of the output signal, and poor S / N. If the pixel has a defect, the following problem occurs.

That is, when a pixel set as a focus adjustment area has a defect such as a linearity defect and an S / N defect of an output signal, the focus is adjusted based on the output signal corrected in consideration of, for example, the linearity defect. It is necessary to deal with pixel defects by making adjustments.

On the other hand, when a pixel set as a focus adjustment area has a defect such as a white defect or a black spot, it is difficult to correct an image based on image information obtained by pixels surrounding the pixel. Therefore, an imaging element having a defect such as a white defect or a black spot in a pixel set as a focus adjustment area cannot be used in a solid-state imaging device, and is sometimes discarded.

Here, since the image pickup device is expensive in the camera system, if the pixel set as the focus adjustment area has a defect, if it is discarded, for example, the cost of the image pickup apparatus or the camera system becomes low. Therefore, improvement has been desired because it becomes difficult.

Accordingly, an object of the present invention is to reduce the cost of an imaging device and a camera system.

[0011]

In order to solve the above-mentioned problems, an image pickup apparatus according to the present invention comprises a focus adjustment area which is a part of an image pickup area of an image pickup device and has no defect in the image pickup area. The focus is adjusted based on the output signal.

Further, a camera system according to the present invention includes the above-described image pickup apparatus, an image pickup lens for condensing light from a subject on the image pickup apparatus, and holding means for holding an image pickup signal output from the image pickup apparatus. .

[0013]

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

FIG. 1 is a configuration diagram of a camera system according to an embodiment of the present invention. In FIG. 1, reference numeral 100 denotes an imaging optical system (LNS) having a plurality of imaging lenses; 200, a central processing unit (CPU) for controlling the operation of the entire imaging device;
Reference numeral 0 denotes a switch device (SWS) that instructs an operation when pressed by a user, 400 denotes an image sensor (SNS) having at least an image capturing area, and 500 denotes an integrated circuit device that drives, reads, and performs image processing of the image sensor 400 ( LS
I) and 600 are liquid crystal display devices (LCDs) for displaying captured images, and 700 is a memory card (MC) for storing captured images, which is separated from the camera system main body by a broken line.

The image pickup device 400 may be equipped with a peripheral circuit for processing an output signal from the image pickup area.

FIG. 2 is an internal configuration diagram of the image pickup optical system 100 shown in FIG. The imaging optical system 100 is for condensing light from a subject (not shown) and irradiating the light to the imaging element 400.

The imaging optical system 100 includes a first lens group grp1 including a negative lens r1, a positive lens r2, and r3, a second lens group grp2 including a cemented lens of a negative lens r4, a negative lens r5, and a positive lens r6. A positive third group grp3 including a stop ST and a positive lens r7, and a fourth group grp4 including a cemented lens of a negative lens r8 and a positive lens 9 are provided.

In FIG. 2, the left side indicates the object side, the right side indicates the image plane side, and F1 indicates an infrared ray (IR).
Cut filter, LPF is optical low pass filter,
L1 indicates the optical axis of the imaging optical system 100.

Next, the operation of FIG. 2 will be described.
For example, the angle of view of the subject is adjusted based on an instruction input by the user pressing a switch provided on the switch device 300. The angle of view is adjusted, for example, by the second lens group grp2 and the fourth lens group grp4.
Are moved in the directions of the arrows to zoom the focal length from wide angle to telephoto. That is, the focal length is zoomed from wide angle to telephoto by simultaneously moving the second lens group grp2 to the image plane side and the fourth lens group grp4 to the subject side.

Next, focus adjustment is performed on the subject by, for example, a phase difference detection method. Focus adjustment
For example, the second lens group grp2 is moved in the direction of the optical axis L1 by a lens driving mechanism (not shown) having a motor and a gear train, so that the subject is focused on the image sensor 400.

FIG. 3 is a circuit diagram of the image pickup device 400 shown in FIG. In FIG. 3, for convenience of explanation, 2 lines ×
Although a two-row pixel array is shown, in practice, for example, 1
It has pixels of 080 rows × 1920 columns.

In FIG. 3, reference numerals 1 and 51 denote first and second photoelectric converters each having a MOS transistor gate and a depletion layer below the gate. Reference numerals 2 and 52 denote photogates. Reference numerals 3 and 53 denote a horizontal scanning unit 16. Storage capacity 2 based on signal
And the charge accumulated in the source follower amplifier M
This is a transfer switch MOS transistor that transfers data to the OS transistor 5 side.

Reference numeral 4 denotes a reset MOS transistor for resetting the source follower amplifier MOS transistor 5, and 6 denotes a source follower amplifier MOS transistor 5.
Is a vertical select switch MOS transistor for selecting a read line for outputting the electric charge accumulated in the MOS transistor.

7 is a source follower amplifier MOS
A load MOS transistor of the transistor 5, a dark output transfer MOS transistor 8 for transferring a dark output signal, a bright output transfer MOS transistor 9 for transferring a bright output signal, 1
0 is a dark output storage capacity C for storing the transferred dark output signal.
_TN and 11 are bright output storage capacitors _CTS for storing the transferred bright output signals.

Also, 12 and 54 are from the vertical scanning unit 15
Output storage capacitance C based on the signal of _TN10 and light output storage
Product capacity C_TSDifferential output of each signal stored in 11 etc.
A vertical transfer MOS transistor for transferring to the amplifier 14 side,
13 and 55 are vertical output line reset MOS transistors
It is.

FIG. 4 shows the light receiving sections 30-11 to 30 shown in FIG.
It is sectional drawing of 30-22 and its peripheral view. In FIG. 4, 17 is a P-type well, 18 and 58 are gate oxide films, 1
9 and 59 are first layer poly-Si, and 20 and 50 are second layer poly-S.
i and 21 are n ⁺ floating diffusion (hereinafter referred to as “FD”) regions, 22 is a color filter that transmits light in a specific wavelength range, and 23 is the imaging optical system 10.
The first and second photoelectric conversion units 1 and 5 efficiently convert the light flux from zero.
1 is a microlens for guiding the lens to 1.

The n ⁺ FD region 21 is connected to the first photoelectric converter 1 and the second photoelectric converter 51 via the transfer MOS transistors 3 and 53. In FIG. 4, the first photoelectric conversion unit 1 and the second photoelectric conversion unit 51 are shown separately from each other. However, the boundary is actually very small, and in practice, the first photoelectric conversion unit 1 and the second The photoelectric conversion unit 51 may be considered to be in contact with the photoelectric conversion unit 51.

FIGS. 5 to 9 show the image pickup device 40 shown in FIG.
FIG. 11 is a plan view of an imaging region of No. 0 and corresponds to FIG. 10. In FIG. 5 to FIG. 9, a portion ■ indicates a defective pixel. As shown in FIG. 5, when the pixels at positions 61, 62, 64, and 66 where the focus adjustment area is to be set are defective, those areas are set as the focus adjustment areas as shown in FIG. Instead, focus adjustment areas are set at positions 61 ', 62', 64 'and 66' adjacent to those areas, for example.

More specifically, for example, as shown in FIGS.
Positions 61 and 6 are set so that no defective pixel is included in 7.
Positions 61 ', 6 next to one row or one column of 2, 64 and 66
A defective pixel is included at positions 61 to 67 where the focus adjustment areas are set at 2 ', 64' and 66 '(FIG. 7), or as shown in FIGS. The focus adjustment areas are set at positions 61 ′, 62 ′, 64 ′, and 66 ′ moved in one direction from these positions 61 to 67 so as not to be located.

In particular, as shown in FIG. 9, the positions 61 'to 67' adjacent to the positions 61 to 67 are irrespective of the presence or absence of the pixel defect at the positions 61 to 67 for which the focus adjustment area is to be set.
Is set as the focus adjustment area, the distance between the respective focus adjustment areas does not change, so that focus adjustment can be performed in the same manner as an image sensor having no defective pixels.

As described above, in the present embodiment, the case where the focus adjustment area is provided at a plurality of positions 61 to 67 and the like has been described as an example. However, the focus adjustment area is provided only at the center of the imaging area of the image sensor 400, for example. There may be.

[0032]

As described above, the imaging apparatus according to the present invention adjusts the focus based on the output signal from the focus adjustment area composed of defective pixels, so that the cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is an internal configuration diagram of the imaging optical system shown in FIG.

FIG. 3 is a circuit configuration diagram of the imaging device and the integrated circuit device shown in FIG.

FIG. 4 is a sectional view of a light receiving unit shown in FIG. 3 and a peripheral view thereof.

FIG. 5 is a plan view of the imaging device shown in FIG.

FIG. 6 is a plan view of the image sensor shown in FIG.

FIG. 7 is a plan view of the imaging device shown in FIG.

FIG. 8 is a plan view of the image sensor shown in FIG.

FIG. 9 is a plan view of the imaging device shown in FIG.

FIG. 10 is a plan view of a conventional image sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 imaging optical system 200 central processing unit 300 switch device 400 imaging device 500 integrated circuit device 600 liquid crystal display device 700 memory card

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H011 AA03 BA21 BA34 BB02 2H051 BA14 CB21 CB22 CB26 DA03 DA08 DA10 5C022 AB30 AC42 AC51 AC69 5C024 CX21 JX09

Claims (7)

[Claims] 1. An imaging apparatus, wherein the focus is adjusted based on an output signal from a focus adjustment area which is a part of an imaging area of an imaging element and has no defect in the imaging area. 2. The image pickup apparatus according to claim 1, wherein the image pickup device includes a plurality of the focus adjustment regions. 3. If the defective pixel is located at a position where the focus adjustment region is to be set, the focus adjustment region is set at a position shifted in a predetermined direction from the position. The imaging device according to claim 1 or 2, wherein 4. When there is the defective pixel at any of the positions where the focus adjustment area is to be set, the focus area where the defective pixel is located or the positions of the plurality of focus adjustment areas are determined. The imaging apparatus according to claim 2, wherein the focus adjustment area is set at a position moved in the same direction. 5. The imaging device according to claim 1, wherein the defect is a white defect or a black spot. 6. The imaging apparatus according to claim 1, wherein the adjustment of the focus is performed by a phase difference detection method. 7. An imaging device according to claim 1, wherein the imaging device focuses light from a subject on the imaging device, and an imaging signal output from the imaging device is held. A camera system comprising: a holding unit.