JP2000292686A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an AF speed, and to accurately adjust a focus by providing a second microscopic lens group for equally dividing a light flux of the object image light and a pair of second light receiving element groups for respectively receiving the equally divided light fluxes, and arranging a plurality of focus detecting block rows regularly arranged with the second microscopic lens group and a pair of second light receiving element groups in plural areas. SOLUTION: An image pickup element is composed of an image pickup part used for photographing a picture element signal and focus detecting parts for using the picture element signal for detecting a focus. This image pickup part is formed over the almost whole surface, and the focus detecting parts are formed in a part of it. Units of a pair of photodiodes 201a, 201b are arranged in a plurality in the focus detecting parts 200A to 200C. A photodiode 101 is arranged in the image pickup part. A microlens 206 is arranged to a pair of photodiodes 201a, 201b in the focus detecting parts 200A, 200C, and a microlens 106 is arranged to the photodiode 101 in the image pickup part 100, respectively.

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 having a focus adjusting function and performing photographing using an electronic image pickup device.

[0002]

2. Description of the Related Art Conventionally, various techniques relating to an image pickup apparatus for electronically capturing a subject image using an electronic image pickup element have been disclosed.

For example, Japanese Patent Laid-Open Publication No. Hei 10-21737 discloses a technique relating to an image pickup apparatus employing a so-called "hill-climbing method" as an autofocus (hereinafter, referred to as AF) method. The hill-climbing method is a method of searching for a photographing lens position at which the contrast of a subject image picked up by an image sensor is maximized.

Japanese Patent Application Laid-Open No. 10-197783 discloses a technique relating to an image pickup apparatus employing a TTL phase difference detection method. In such a TTL phase difference detection method, a diaphragm member is driven to perform pupil division in a time division manner, and a light beam passing through the pupil is received by an image sensor to detect a phase difference.

On the other hand, Japanese Patent Publication No. 57-49841 discloses a technique relating to a TTL phase difference detecting device. This is a method called fly lens method,
The light beam that has passed through the lens array is received by a pair of light receiving elements forming a line sensor, and the signal of the line sensor is processed to calculate the amount of image shift, that is, the amount of phase difference, and is fed back to the extension amount of the focus sync lens. The focus adjustment is performed.

[0006] Japanese Patent Application Laid-Open No. 10-274562 discloses a technique relating to a TTL phase difference detecting device employing a re-imaging method. On the other hand, Japanese Patent Application Laid-Open
Japanese Patent Application Publication No. 2016683 discloses a technique relating to a re-imaging TTL phase difference detection device having a plurality of focus detection areas.

[0007]

However, in the above-mentioned hill-climbing method, since the photographing lens is moved to find the peak of the contrast of the subject image of the image sensor, there is a problem that the AF speed is slow.

In the technique disclosed in Japanese Patent Application Laid-Open No. H10-197783, a pupil is divided by driving a diaphragm member by a mechanical mechanism, so that a driving mechanism is required.
Since a mounting space is required, miniaturization is difficult. Furthermore, since a time difference occurs in the formation of a plurality of divided pupils to be divided, there is a problem that the detection accuracy for a moving subject is significantly deteriorated. Further, there is a problem that it takes time to move the mechanical diaphragm member, and the AF speed becomes slow.

On the other hand, in the focus detection device disclosed in Japanese Patent Publication No. 57-49841, a part of a light beam from a subject that has passed through a photographing lens must be divided and guided. There is a problem that it is subject to various restrictions.

The focus detecting device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 10-274562 requires a re-imaging optical system in addition to the above-described problem of the optical path splitting, and further has a problem that space restrictions are increased. have.

The focus detecting device disclosed in Japanese Patent Application Laid-Open No. Hei 8-201683 requires a re-imaging optical system and an AF sensor for each of a plurality of focus detecting areas. This causes an increase in space.

The present invention has been made in view of the above problems, and has as its object to provide a low cost, space saving, and wide focus detection area without adding a new mechanism or optical system. Another object of the present invention is to provide an imaging apparatus having a focus adjustment function capable of improving the AF speed and performing accurate focus adjustment.

[0013]

To achieve the above object, according to a first aspect of the present invention, there is provided an image pickup apparatus having an image pickup device for receiving subject image light passing through a photographing lens. A first light receiving element group for receiving the subject image light to be processed, and a first microlens group for condensing the subject image light with respect to the first light receiving element group. An imaging area for generating an output of the first light receiving element group, a second minute lens group for pupil-dividing a light beam of subject image light passing through the photographing lens, and a light beam pupil-divided by the second minute lens group And a pair of second light receiving element groups each receiving light, and a focus detection area unit that generates an output of the pair of light receiving element groups to perform focus detection, and Two micro lens groups and the pair of second light receiving element groups Focus detection block columns regularly arranged, an imaging apparatus characterized by formed by a plurality arranged in a plurality of regions are provided.

According to a second aspect, in the first aspect, the plurality of focus detection block rows arranged in the plurality of regions include a pupil division direction of the second microlens group and the pair of first focus detection blocks. An imaging device is provided, wherein the two light receiving element groups are arranged so that the arrangement directions thereof are different from each other.

Further, in a third aspect, in the first aspect, the first light-receiving element group of the imaging area section;
An imaging apparatus is provided, wherein the arrangement pitch on the imaging element is different from that of the second light receiving element group in the focus detection area.

According to the above-described first to third aspects, the following operations are provided.

That is, according to a first aspect of the present invention, in an image pickup apparatus having an image pickup device for receiving subject image light passing through a photographing lens, in the image pickup area, the first light receiving element group passes the photographing lens. Subject image light is received,
The subject image light is condensed on the first light receiving element group by the first minute lens group, and the output of the first light receiving element group is generated for imaging. In the focus detection area, the luminous flux of the subject image light passing through the photographing lens is pupil-divided by the second microlens group, and the pupil is pupil-divided by the second microlens group by a pair of second light receiving element groups. Are respectively received, and outputs from the pair of light receiving element groups are generated to perform focus detection. A plurality of focus detection block rows in which the second micro lens group and the pair of second light receiving element groups are regularly arranged are formed in a plurality of areas.

According to a second aspect, in the first aspect, the plurality of focus detection block rows arranged in the plurality of regions are arranged such that the plurality of focus detection block rows are arranged in a pupil dividing direction of the second microlens group and the pair of first focus detection blocks. The two light receiving element groups are arranged so that the arrangement directions are different from each other. Further, in a third aspect,
In the first aspect, the first area of the imaging area section
The light receiving element group and the second light receiving element group in the focus detection area differ in the arrangement pitch on the image sensor.

[0019]

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

FIG. 1 is a configuration diagram of an optical system of an image pickup apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, a focusing lens 1a for receiving light from a subject is arranged at a predetermined position, and a stop 2 is arranged on the optical axis. The photographing optical system 1 is constituted by the focusing lens 1a, the diaphragm 2, and the like. A beam splitter 3 is disposed on the optical path of the subject light via the photographing optical system 1, and an infrared cut filter 4 and a low-pass filter (hereinafter, referred to as “light-pass filter”) are provided on the optical path of the light reflected by the beam splitter 3. LPF) 5 and an image sensor 6 are provided.

On the other hand, a finder optical system 10 including a mirror 7, a pentaprism 8, and an eyepiece 9 is provided on the optical path of the light transmitted through the beam splitter 3.

The stop 2 can hold a predetermined stop opening, has a shutter function, and has a function of completely blocking light.

In such a configuration, a part of the luminous flux passing through the photographing optical system 1 is reflected downward by the beam splitter 3, the infrared light component is removed by the infrared light cut filter 4, and the moiré is removed by the LPF 5. Is reduced, the image is captured by the image sensor 6. A part of the luminous flux of the subject transmitted through the beam splitter 3 is reflected by a mirror 7 and then guided to a finder optical system 10 including a pendant prism 8, an eyepiece 9, and the like, and observed by a photographer.

Next, FIG. 2 is a configuration diagram of an electric system of the image pickup apparatus according to the first embodiment.

As shown in FIG.
A central processing unit (hereinafter, referred to as CPU) 31a for controlling the entire system, a read-only memory (hereinafter, referred to as ROM) 31b, and a random access memory (hereinafter, RAM)
) 31c, an analog / digital converter (hereinafter, referred to as an analog / digital converter)
ADC) 31d, EEPROM as nonvolatile memory
It has at least OM31e.

Further, the microcomputer 31 includes a lens drive unit 32, an aperture drive unit 33, an image sensor control unit 43, a display unit 46, a first release switch (hereinafter, referred to as 1RSW) 47, a second release switch (hereinafter, 2R SW).
SW) 48 and an area selection SW 49.

The output of the image sensor controller 43 is connected to the input of the image sensor 16 (same as the image sensor 6 in FIG. 1), and the output of the image sensor 16 is connected to the input of the video signal processor 42. It is connected. The output of the video signal processing unit 42 is output to the recording unit 44,
5, a display unit 46, a focus detection calculation unit 50, and an input of an auto white balance (hereinafter, referred to as AWB) unit 51.

The output of the photometry / exposure calculation unit 45 and the output of the focus detection calculation unit 50 are
Connected to the input.

In such a configuration, the microcomputer 3
1 performs a series of operations according to a sequence program stored in the ROM 31b therein. The EEPROM 31e inside the microcomputer 31 has focus adjustment,
Correction data relating to photometry / exposure calculation, AWB, etc. is stored for each camera. The imaging device 6 includes the imaging optical system 1
The image of the subject formed by is captured and converted into an electric signal.

The video signal processing section 42 processes an electric signal which is a pixel signal from the image sensor 6 to generate a video signal. The detailed configuration will be described later.

The photometric / exposure calculating section 45 calculates a photometric value and an exposure control value based on the video signal processed by the video signal processing section 42. Also, the image sensor control unit 4
Reference numeral 3 controls the electronic shutter of the image sensor 6 at the time of shooting based on the shutter speed output from the photometry / exposure calculation unit 45. In this embodiment, the diaphragm 2 in the photographing optical system 1 is controlled at the time of photographing based on the aperture value data calculated by the exposure calculation of the photometer / exposure calculator 45.

The aperture driving unit 33 drives the aperture 2 based on a command from the microcomputer 31. Further, the focus detection calculation unit 50 performs a focus detection calculation based on the video signal processed by the video signal processing unit 42. As a result of the focus detection calculation, focus determination data, a focus sync lens driving amount, and the like are transmitted to the microcomputer 31.

The AWB unit 51 automatically controls the white balance based on the video signal processed by the video signal processing unit 42. The display unit 46 includes the microcomputer 3
Under the control of 1, the image captured by the image sensor 6 and the information inside the camera are transferred to a liquid crystal display (LCD).
Display).

The 1RSW 47 and 2RSW 48 are switches linked to the release button. The 1 RSW 47 is turned on when the release button is depressed in the first stage, and the 2RSW 48 is turned on when the second stage is depressed. The area selection SW 49 is a switch for selecting an AF area, and moves and selects a predetermined AF area every time the switch is turned on. The microcomputer 31 performs the photometry and the AF operation when the 1RSW 47 is turned on, and performs the exposure operation and the image recording operation when the 2RSW 48 is turned on.

In addition to the above, the lens drive section 32 is controlled by the focusing sync lens 1a based on a command from the microcomputer 31.
Drive.

FIG. 3 is a diagram showing a detailed configuration of the image pickup device 6. As shown in FIG.

As shown in the figure, in the image sensor 6 as a MOS sensor, a plurality of pixel units 110 each including a photodiode as a light receiving element are two-dimensionally arranged. Is configured to control the accumulation operation of The control unit 111 controls the X shift register 112 and the Y shift register 113 to select the output Sn of the pixel unit from the switches SWxn and SWyn, and outputs the output Sn to the outside through the output unit 114.

FIG. 4C shows the image pickup device 6.
Is functionally divided into two parts and described. As shown in the figure, the image sensor 6 includes an imaging unit 100 for using pixel signals for photographing, and a focus detection unit 200 for using pixel signals for focus detection. The imaging unit 100 is formed on substantially the entire surface, and the focus detection unit 20
0 is formed in a part thereof. Further, in the photographing screen 120, the focus detection area 200A is disposed on the optical axis, and the focus detection area 200B is disposed off the optical axis and perpendicular to the focus detection area 200A.

On the other hand, a micro lens is formed on the front surface of the photodiode as the light receiving element. As a technique for improving the light sensitivity of the image sensor, by providing microlenses at positions corresponding to the respective photodiodes, the incident light is efficiently condensed on the light receiving unit.
A technology called a so-called on-chip micro lens has been established. In the imaging unit 100, the microlenses are set so as to optimize the light sensitivity as described above.

FIG. 4A is a diagram showing an arrangement of photodiodes as light receiving elements on the image sensor 16. The focus detection units 200A to 200C include a pair of photodiodes 20.
A plurality of units 1a and 201b are arranged. Further, photodiodes 101 are arranged in the imaging unit 100.

FIG. 4B is a diagram showing the arrangement of the photodiodes and the microlenses.

In the focus detection units 200A to 200C, the microlens 206 is arranged for the pair of photodiodes 201a and 201b, and in the imaging unit 100, the microlens 106 is arranged for the photodiode 101.

Next, FIG. 5 is a diagram showing a general sectional structure of an image pickup device having an on-chip micro lens formed thereon.
The imaging unit 100 of the imaging device 6 in the imaging device according to the present embodiment has a configuration substantially similar to that of FIG.

As shown in FIG. 5, a light receiving portion 1 is formed in a semiconductor substrate 131 made of silicon by a diffusion layer or the like.
A photodiode constituting 33 is formed.

The circuit portion 132 and the gate electrode 134 constituting the circuit for amplifying the output of the photodiode are covered with a light shielding film 135. Further, the light receiving portion 133 is formed corresponding to the opening of the light shielding film 135, and a color filter 137 is formed on the light receiving portion 133 and the light shielding film 135. Further, the color filter 137 has a predetermined curvature r and a focal length f1.
A micro lens 139 having a spherical surface is formed.

On the other hand, the micro lens 206 corresponding to the focus detecting section 200 is
6 (139) are different in characteristics such as curvature and focal length, and a pair of light receiving elements, photodiodes A and B, are arranged almost on the focal plane of the micro lens 206. Then, the microlens 206 pupil-divides the light beam passing through the imaging optical system 11 as shown in FIG. 6, and acts so that each of the divided light beams enters the pair of light receiving elements A and B, respectively.

The principle of focus detection is the same as that of the phase difference detection method disclosed in the above-mentioned Japanese Patent Publication No. 57-49841, and a detailed description thereof will be omitted.

Next, FIGS. 7A and 7B show examples of focusing, front focus, and rear focus in the focus detection section 200, respectively. still,
Actually, the micro lens Ln group, the light receiving elements An and Bn
The group is fixed, and the position of the imaging optical system 1 moves. Here, for convenience of explanation, the relative positional relationship will be described with the position of the imaging optical system 1 fixed.

The focal length of the micro lens Ln is f2, and the micro lens Ln and the light receiving element photodiode A
It is substantially equal to the distance between n and Bn.

First, at the time of focusing, light rays R1, R2, and R which are light east from the same subject and have passed through different exit pupils.
3, R4,... Have the same amount of light received by the adjacent An and Bn around the optical axis of each microlens Ln. For example, for the light rays R3 and R4, the micro lens L2 and the light receiving element A
2 and B2 correspond.

In the case of the front focus, the light receiving amounts of the light receiving elements A and B of the light passing through the different microlenses, that is, the light receiving amounts of the non-adjacent light receiving elements A and B match. For example, for light rays R3 and R4 from the same subject, micro lens L3
And the light receiving element B3, and the micro lens L1 and the light receiving element A1, respectively, so that the images are shifted by two pitches.

On the other hand, in the case of the rear focus, the detection elements having the same amount of received light are adjacent to each other, but the light incident on the adjacent light receiving elements is light passing through different microlenses. For example, rays R3 and R4 from the same subject
Since the microlens L1 and the light receiving element B1 correspond to each other, and the microlens L3 and the light receiving element A3 respectively correspond to each other, the image is shifted by two pitches in the direction opposite to that at the time of the front focus.

As described above, an image shift occurs according to the amount of focus shift. Actually, the focus detection accuracy decreases with the image shift amount (phase production amount) in the unit of one pitch, so that focus detection for one pitch or less is performed by performing a known interpolation operation or the like. By detecting the image shift amount in this way, the focus shift amount of the photographing lens can be obtained.

Here, FIG. 8A shows the pixel units located in the image pickup unit 100 among the pixel units arranged two-dimensionally in the horizontal direction and the vertical direction shown in FIG. The configuration of 110 will be shown and described.

In the figure, in the pixel unit 110, the output of the photodiode 101 is input to the pixel amplifier circuit 102 which amplifies the charge generated by the photodiode 101. The pixel amplification circuit 102 includes a first-stage amplifier 104 and a sample-and-hold unit 105.

The first-stage amplifier 104 comprises an amplifier A1, a storage capacitor C1, and a switch SW1, and constitutes an integrator. The output of the first-stage amplifier 104 is
The data is input to the sample and hold unit 105. The sample hold unit 105 includes a switch SW2, a hold capacitor C2, and a buffer A2.

When the switches SW1 and SW2 are turned on, the pixel unit 110 is initialized, and subsequently, when the switch SW1 is turned off, an accumulation operation is started. Further, when the switch SW2 is turned off, the accumulation level is held by the hold capacitor C2, and the accumulation operation ends. The ON / OFF timing of the switches SW1 and SW2 is controlled by the control unit 111.

Further, the accumulation level held by the hold capacitor C2 is equal to Vs via the buffer A2.
n, and are selected by the X shift register 112 and the Y shift register 113 and output to the output unit 114.

The focus detection unit 200 includes a pair of photodiodes 201a and 201b that receive light beams split at the exit pupil of the photographing lens 11 by the microlens group, respectively, and the photodiode 201
a, a pixel amplifying circuit 202 for amplifying generated charges of
a and 202b are arranged.

On the other hand, FIG.
FIG. 3 is a diagram showing a detailed configuration of a 0.

As shown in FIG.
Each of 2a and 202b has the same circuit configuration as the pixel amplifier circuit 102 described above. The pixel amplification circuit 202a,
The output of 202b is selectively connected to the output Vsn via switches SWa and SWb controlled by the control unit 111. The output Vsn is selected by the X shift register 112 and the Y shift register 113 outside the pixel unit 210 and output to the output unit 114, similarly to the pixel unit 103.

The photodiode 10 of the image pickup unit 100
A color filter is arranged on the front surface of 1. This color filter array is a so-called Bayer array as shown in FIG. That is, in FIG. 9, R, G, and B indicate color filters that selectively transmit red, green, and blue, respectively.

On the other hand, the photodiode 20 of the focus detection unit
No color filters are arranged on the front surfaces of 1a and 201b, and only the imaging unit 100 is arranged.

As described above, the plurality of focus detection areas 200
The focus detection is performed for A, 200B, and 200C, and processing by a known algorithm such as automatically selecting the closest subject among them can be performed. Further, the photographer can select an AF area with an area selection switch 49 described later and focus on that area. In the focus detection area 200A, it is possible to perform focus detection on a subject having a horizontal contrast with respect to the shooting screen 120, for example, a vertical line.

On the other hand, the focus detection areas 200B,
At 200C, it is possible to perform focus detection on a subject having a vertical contrast with respect to the photographing screen 120 shown in FIG. 9, for example, a horizontal line. Therefore, it is possible to detect a focus even for a subject having only one direction of contrast.

When an image is created, the focus detection areas 200A to 200C need to be supplemented because there is no image data.

The method of supplementing the image data will be described.
In FIG. 4A described above, for example, the focus detection area 2
The portions of the photodiodes 201a and 201b of 00A are obtained by interpolating using pixel signals of the photodiodes 101A to 101E which are peripheral pixels and belong to the imaging unit 100.

At this time, it goes without saying that only the pixel data of the same color filter may be used. Various methods such as simple averaging or weighted averaging of the pixel signals of the photodiodes 101A to 101E can be adopted as the interpolation calculation method. Since such a method is already known, a detailed description is omitted.

Next, FIG. 10 shows the video signal processing section 42.
Is shown and described in detail.

In FIG. 10, a fixed pattern noise (FPN) removing circuit 78 removes FPN and the like from the image signal of the image sensor 16. Gain control amplifier AM
P79 amplifies the output of the FPN removal circuit 78 with a predetermined gain.

The A / D converter 80 converts the output of the gain control amplifier 79 into a digital signal by AD conversion. The process processing circuit 81 performs various processes on the video signal converted into the digital signal.

The image sensor control section 43 outputs a drive signal to the image sensor 16 and controls its operation. The image sensor control unit 43 includes a timing generator 82 and a signal generator 83.

That is, the timing generator (TG) 8
Reference numeral 2 denotes a drive signal such as a drive pulse for driving the image sensor 16, a sample / hold pulse of the FPN removing circuit 78, and an A / D converter of the A / D converter 80.
A D conversion timing pulse is generated. The signal generator (SG) 83 includes the timing generator 82
And a signal for synchronizing with the microcomputer 31.

The recording section 44 comprises a DRAM 84, a compression / expansion circuit 85, and a recording medium 86. The video signal (pixel data) output from the process processing circuit 81 in the video signal processing unit 42 is stored in the DRAM 84.
The compression / expansion circuit 85 performs a compression process for reducing the amount of pixel data stored in the DRAM 84 for recording and a decompression process for restoring the compressed data read from the recording medium 86. The recording medium 86 records the compressed still image data.

Hereinafter, the operation of the microcomputer 31 will be described in detail with reference to the flowchart of FIG. In the following description, the time chart of FIG.

When the power switch (not shown) is turned on or a battery is inserted, the microcomputer 31 starts operating, and the internal RO
The sequence program stored in M31b is executed.

That is, when entering this sequence, first, each block in the image pickup apparatus is initialized (step S1). Subsequently, the state of the 1RSW 47 is detected (Step S
2).

When the 1RSW 47 is off, the image sensor 6
An image pickup operation, which is an accumulation (exposure) and readout operation in the image pickup unit, is performed (step S5), and the photometry / exposure calculation unit 45 performs photometry The aperture control value of the aperture 12 and the electronic shutter speed of the image sensor 6 at the time of the main exposure shooting (image recording) are calculated (step S6), and the process returns to the step S2.

On the other hand, when the 1RSW 47 is on, the accumulation operation (exposure for AF) of the focus detection unit 200 of the image pickup device 6 is performed, and the image signal of the focus detection unit 200 is read out (step S3), and the focus detection based thereon is performed. An operation is performed (step S4).

This focus detection calculation is executed at the timing F1 in FIG. 12 (f). The calculation results in the focus detection areas 200A, 200B, 200C are compared, and the shortest area is selected. A known method such as the above can be adopted.

Subsequently, it is determined whether the result of the focus detection calculation is in focus or out of focus (step S7).
Move to 9. If out of focus, the process proceeds to step S8 to calculate and drive the amount of movement of the focusing lens 1a so as to achieve focusing based on the focus detection calculation result. Then, returning to step S2, the AF operation as described above is repeated. The driving of the focusing lens 1a is executed at a timing F2 in FIG.

At step S9, it is detected whether or not the 2RSW 48 is turned on.
Go to 0. On the other hand, if the 2RSW 48 is off, the process proceeds to step S2, and the AF is performed while the 2RSW 48 is on.
Continue operation.

In the subsequent steps S10 and thereafter, the main exposure operation is performed.

That is, the microcomputer 31 controls the aperture control unit 33 to narrow the aperture 2 to the aperture value for exposure (step S
10), the image sensor control unit 43 outputs the charge reset signal RES
Is turned off (see FIG. 12B), the accumulation of the image sensor 6 is started, and the main exposure is performed by controlling the electronic shutter speed based on the exposure calculation (step S11).

This main exposure operation is executed at the timing of F3 in FIG.

The electronic shutter operation is performed by generating a charge storage signal HOLD at a predetermined timing according to the shutter speed by the image sensor control unit 43 to hold the charge stored in the photodiode 101 (FIG. 12).
(C)).

Next, the image pickup device controller 43 outputs the image read signal DCLK to the image pickup device 16, and the video signal processor 42 outputs the image read signal DCLK in synchronization with the signal DCLK (see FIG. 12D). The image signal (image sensor signal) is A / D converted and read out (step S12). The reading of the image data is executed at the timing of F4 in FIG.

Further, the microcomputer 31 controls the aperture control unit 33 to send a command to open the aperture to open the aperture 12 (step S13), perform processing such as compression of the read image signal, and then perform recording. It is stored in the medium 86 (step S14). This image processing and recording operation is shown in FIG.
This is performed at the timing of F5 of 2 (f).

The above-described series of photographing operations is completed, the process returns to step S2, and the above operations are repeated.

Next, a second embodiment of the present invention will be described.

The second embodiment differs from the first embodiment in that the arrangement of the focus detection areas is changed.

First, FIG. 13 is a diagram showing a state of arrangement of a focus detection area of an image pickup device in an image pickup apparatus according to the second embodiment.

As shown in the figure, on the photographing screen 120, the photographing screen
Focus detection area 300A arranged in parallel with the long side direction of 0
And a focus detection area 300 centered on the optical axis of the photographing lens.
A and 300B arranged in a direction perpendicular to A.

FIG. 14 shows an arrangement of photodiodes in an image pickup device of an image pickup apparatus according to the second embodiment.

As in the first embodiment described above, the image pickup section 100 is formed over the entire surface of the image pickup element 6, and as shown in FIG. 14, the focus detection section 300A is provided at a portion corresponding to the focus detection area. , 300B are formed.

A plurality of pairs of the photodiodes 301a and 301b of the focus detection unit 300A are arranged in parallel with the long side of the photographing screen 100 to form a focus detection area. On the other hand, a plurality of pairs of the photodiodes 301c and 301d in the focus detection area 300B are arranged in a direction perpendicular to the long side of the photographing screen, that is, parallel to the short side direction, thereby forming a focus detection area.

In the second embodiment, by providing the cross-shaped focus detection area as described above, it is possible to detect the focus of the subject existing in the area near the center of the photographing screen regardless of the direction of the contrast. It is possible.

Next, a third embodiment of the present invention will be described.

FIG. 15 is a diagram showing the arrangement of the image pickup device of the image pickup apparatus according to the third embodiment. In the third embodiment, a plurality of combinations of the cross-shaped focus detection areas shown in the second embodiment are further provided.

The cross-shaped focus detection area 410A includes a horizontal focus detection area 400A and a vertical focus detection area 400B. The arrangement of the photodiodes on the image sensor 6 in the vicinity of the similar cross-shaped focus detection areas 410A to 410E is all the same as that shown in FIG.

In the third embodiment, since the number of cross-shaped focus detection areas is further increased, it is possible to perform focus detection over the entire photographic screen without being affected by the direction of subject contrast.

Next, a fourth embodiment of the present invention will be described.

FIG. 16 is a diagram showing the arrangement of the image pickup device of the image pickup apparatus according to the fourth embodiment. The fourth embodiment has a configuration in which the focus detection area is extended obliquely with respect to the side of the photographing screen 120, and two rows of focus detection areas 510 are further provided.
A, 510B are arranged in a cross shape to form a cross focus detection area 5
01A. Further, a plurality of the cross-shaped focus detection areas 501A are arranged. The cross-shaped focus detection area 501A and the pixel configuration around it are as shown in FIG.

Next, a fifth embodiment of the present invention will be described.

The fifth embodiment is a modification of the first embodiment, and differs from the first embodiment in the configuration of the pixel unit.

FIG. 18A is a diagram showing a configuration of a focus detection area 200A in an image pickup device of an image pickup apparatus according to the fifth embodiment, and FIG.
FIG. 2 is a diagram illustrating a configuration of a pixel unit 210 of 0A. FIG.
As shown in FIG. 8A, in the fifth embodiment, in the focus detection area 200A, in addition to the pair of photodiodes 201a and 201b, the imaging photodiode 2
01c.

Further, in FIG. 18B, at the time of focus detection, the accumulation operation is performed with the switch Swg turned off. In this case, the same operation as in the first embodiment is performed.

On the other hand, at the time of capturing the recorded image, in the first embodiment described above, the focus detecting section 200A does not perform the storing operation. However, in the fifth embodiment, the focus detecting section 200A performs the storing operation simultaneously with the image capturing section 100. Perform the operation.

At this time, the switch SWg is turned on,
The output of the photodiode 201c is also supplied to the pixel amplification circuit 202.
By inputting to a, not only a pupil-divided beam but also a wider beam including the pupil-divided beam is received and converted to a voltage signal.

Then, the obtained photodiode 201
a, 201c and photodiode 201
By adding the pixel signals b, it is possible to obtain an image signal corresponding to a case where the entire luminous flux is received.

Thus, the focus detection areas 200A to 200A
By creating an image signal similarly for each of the 200Cs, a higher quality image can be obtained.

FIG. 19 shows the fourth embodiment (FIG. 1).
FIG. 13 is a diagram illustrating an arrangement of photodiodes of a focus detection unit 510A when the fifth embodiment is applied to 7). As shown in FIG.
a and 501b, and an image photodiode 501c. At the time of recording and imaging, the photodiode 501 is used.
An image signal is created by adding the light receiving amounts of a, 501b, and 501c.

As described above, since the microlens 106 of the imaging unit 100 and the microlens 206 of the focus detection unit 200 have different optical characteristics, the amount of received light is different, but this difference in the amount of light is stored in the EEPROM 31e in advance. In this case, the correction is made for each pixel unit of the focus detection unit 200 so as to be adjusted to the imaging unit 100.

Next, a sixth embodiment of the present invention will be described.

The sixth embodiment is a modification of the above-described first embodiment, and is particularly different in the arrangement of photodiodes.

FIG. 21 is a diagram showing an arrangement of a focus detection unit of an image pickup device in an image pickup apparatus according to the sixth embodiment.

As shown in FIG.
In A to 200C, a unit including a pair of photodiodes 201a and 201b for focus detection and the imaging photodiode 101 are alternately arranged. In such a configuration, the detection pitch of the focus detection photodiode is double that of the first embodiment. Therefore, the focus detection accuracy is reduced to about 1/2, but the quality of the image around the focus detection areas 200A to 200C can be improved.

The photodiodes 201a and 201b in the focus detection area 200A are peripheral pixels of the photodiodes 201a and 201b, and are effective as pixel data.
It is determined by interpolation using pixel signals of 〜１０101H.

In the sixth embodiment, the number of effective pixel data for the interpolation calculation is increased as compared with the first embodiment, so that the image quality can be further improved.

Although a unit composed of a pair of photodiodes 201a and 201b for focus detection and the imaging photodiode 101 are alternately arranged, they can be deformed at intervals of 2 to 5 or the like depending on the required accuracy. Of course.

Next, a seventh embodiment of the present invention will be described.

The seventh embodiment is a modification of the above-described first embodiment, and particularly differs in the arrangement of the color filters on the photodiode.

FIG. 20 is a diagram showing an arrangement of a focus detection unit of an image pickup device in an image pickup apparatus according to the seventh embodiment.

In the above-described first embodiment, no color filter is provided in the focus detection units 200A to 200C. However, in the seventh embodiment, the focus detection unit 200A is not provided.
The color filters are regularly arranged in accordance with the Bayer arrangement in the same manner as in the imaging unit 100 including the image filters 200C to 200C. At the time of actual focus detection, focus detection sections 200A to 200C select pixel data of the same color filter and perform focus detection calculation.

It is needless to say that the focus detection operation may be independently performed on the pixel signal of color G or the pixel signal of color B, and both of them may be averaged, or only one having high reliability may be selected. is there. In this case, the detection pitch of the focus detection becomes coarse, but the focus detection units 200A to 200A to
The pixel signal information in the 200C can be adopted, and the quality of the image can be improved.

When a recorded image is created, for example, for the focus detection area 200A, the pixel signals 201a and 201b
(Color G) is added to the resultant value and adopted as pixel data of that portion. Further, the peripheral color G pixel signals 101A to 101D
It is conceivable to perform interpolation processing or the like in consideration of the above. The same processing may be performed for the pixel of color B.

As described above, in the present invention, the pupil-divided microlens group and a pair of light-receiving element groups for receiving the pupil-divided light beam are formed in a plurality of areas on the same chip as the image pickup element. Since the focus detection is performed based on the output of the image pickup device, it is possible to provide an imaging device which has a low-cost, space-saving, wide-field focus detection area, and a high-speed and high-precision focus adjustment function. .

The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments, and it is needless to say that various improvements and modifications can be made without departing from the gist of the present invention. For example, in the above embodiment, the image sensor is described as a MOS sensor, but may be a CCD or other type of solid-state image sensor.

The above embodiments of the present invention include the following inventions.

(1) In an image pickup apparatus having an image pickup device for performing photoelectric conversion of an optical image formed on a light receiving surface after passing through a photographing lens, the light receiving surface is set as a focal position, and the first light-receiving surface is two-dimensionally arranged. And a second microlens array, a first photodetector group arranged near the focal position of the first microlens array, and each configured to output a first video signal, the first photodetector group having a single photodetector as a constituent unit; A second light receiving element group disposed near the focal position of the second micro lens array and configured to output a second video signal, the second light receiving element group being constituted by a pair of light receiving elements. An imaging apparatus comprising: a plurality of focus detection block rows in which an array and the second light receiving element group are regularly arranged;

(2) In the above (1), the plurality of focus detection block rows are arranged so that the arrangement direction of the second light receiving element group is different from each other.

(3) In (1), the first light receiving element group and the second light receiving element group have different arrangement pitches on the image sensor.

[0134]

As described in detail above, according to the present invention,
It has a focus adjustment function that can increase the AF speed and perform accurate focus adjustment at a low cost and in a small space, without adding a new mechanism or optical system, at a low cost and in a small space. An imaging device can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical system of an imaging device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an electric system of the imaging device according to the first embodiment.

FIG. 3 is a diagram showing a detailed configuration of an image sensor 6.

FIG. 4 is a diagram showing a detailed configuration of an image sensor 6.

FIG. 5 is a diagram illustrating a general cross-sectional configuration of an imaging device in which an on-chip microlens is formed.

FIG. 6 pupil-divides a light beam passing through the imaging optical system 11,
FIG. 3 is a diagram illustrating a state in which each split light beam is incident on a pair of light receiving elements A and B, respectively.

FIG. 7 is a diagram illustrating an example of focusing, a front focus, and a rear focus in the focus detection unit 200.

FIG. 8A is a diagram illustrating one of the pixel units arranged two-dimensionally in the horizontal direction and the vertical direction shown in FIG.
FIG. 2 is a diagram illustrating a configuration of a pixel unit 110 located in an imaging unit 100 portion, and FIG. 2B is a diagram illustrating a detailed configuration of the pixel unit 210.

FIG. 9 is a diagram showing a Bayer arrangement.

FIG. 10 is a diagram showing a detailed configuration of a video signal processing unit 42.

FIG. 11 is a flowchart for explaining in detail the operation of the microcomputer 31 of the imaging device according to the first embodiment.

FIG. 12 is a time chart for explaining in detail the operation of the microcomputer 31 of the imaging device according to the first embodiment.

FIG. 13 is a diagram illustrating an arrangement of a focus detection area of an imaging element in an imaging device according to a second embodiment.

FIG. 14 is a diagram illustrating an arrangement of photodiodes in an imaging device of an imaging device according to a second embodiment.

FIG. 15 is a diagram illustrating an arrangement of an imaging device of an imaging device according to a third embodiment.

FIG. 16 is a diagram illustrating an arrangement of an imaging device of an imaging device according to a fourth embodiment.

FIG. 17 is a diagram illustrating a cross-shaped focus detection area 501A and a pixel configuration around it.

18A is a diagram illustrating a configuration of a focus detection area 200A in an imaging device of an imaging device according to a fifth embodiment, and FIG. 18B is a diagram illustrating a configuration of a pixel unit 210 in the focus detection area 200A. FIG.

FIG. 19 shows a fifth embodiment (FIG. 17) with respect to the fourth embodiment (FIG. 17);
FIG. 10 is a diagram showing an arrangement of photodiodes of a focus detection unit 510A when the embodiment is applied.

FIG. 20 is a diagram illustrating an arrangement of a focus detection unit of an imaging device in an imaging device according to a sixth embodiment.

FIG. 21 is a diagram illustrating an arrangement of a focus detection unit of an imaging device in an imaging device according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Imaging optical system 1a Focusing lens 2 Aperture 3 Beam splitter 4 Infrared cut filter 5 LPF 6 Image sensor 7 Mirror 8 Pentaprism 9 Eyepiece 10 Viewfinder optical system

Continued on front page F-term (reference) 2H051 BA06 BA18 CB09 CB17 CB24 CB29 DA07 DA10 5C022 AA13 AB03 AB12 AB17 AB18 AB27 AC02 AC03 AC13 AC31 AC32 AC42 AC54 AC56 AC69 AC74 5C065 AA03 BB02 BB08 BB11 CC01 CC08 CC05 DD12 DD17 DD02 DD17 DD06 DD10 GG18 GG30 GG32 GG44

Claims (3)

[Claims] 1. An image pickup apparatus having an image pickup device for receiving subject image light passing through a taking lens, comprising: a first light receiving element group for receiving subject image light passing through the taking lens; A first micro lens group for converging subject image light, and an imaging area for generating an output of the first light receiving element group for performing imaging, and passing through the imaging lens. A second minute lens group that pupil-divides the light beam of the subject image light to be split, and a pair of second light-receiving element groups that respectively receive the light beams that are pupil-divided by the second minute lens group. A focus detection area for generating an output of the pair of light receiving elements for performing detection, wherein a focus is provided in which the second micro lens group and the pair of second light receiving elements are regularly arranged. Arrange multiple detection block rows in multiple areas Imaging apparatus characterized by form was. 2. The plurality of focus detection block arrays arranged in the plurality of regions are such that a pupil division direction of the second micro lens group and an arrangement direction of the pair of second light receiving element groups are different from each other. The imaging device according to claim 1, wherein the imaging device is disposed at a position where the image is captured. 3. The arrangement of the first light receiving element group in the imaging area and the second light receiving element group in the focus detection area in an arrangement pitch on the imaging element. 2. The imaging device according to 1.