JPH10104503A - Focus detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the distortion of an image by arranging adjacent photoelectric transducer trains in a relation in which their phases with respect to an object image are shifted and performing a focus dtection based on focus detection information of the plural photoelectric transducer trains to improve the variation of focus detections to be generated by a phase in/phase out. SOLUTION: This device is constituted of a photoelectric transducer element 11 having a silver salt-contg. film 2, a semitransmission main mirror 3, reflection mirrors 4, 6, 10, an IR cutting filter 7, a diaphragm 8, a second order image formation system 9 and two area sensors 11-1, 11-2 or the like. In this device, adjacent photoelectric transducer trains are arranged in a relation in which they are shifted with each other with respect to luminous fluxex from an object to be photographed by the prescribed pitch of the photoelectric transducer 11 and one focus detection value is obtained based on a defocusing amount to be detected from outputs of plural adjacent photoelectric transducer trains. Thus, even when a focus detecting range is expanded, a constant defocusing amount is made detectable by preventing the influence of the variation of focus detections to be generated phase in/phase out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing device such as a camera and a video, or a focus detecting device of various observation devices. More specifically, the present invention relates to a focus detection device that enables two-dimensional and continuous focus detection over a wide range on a photographing screen or an observation screen.

[0002]

2. Description of the Related Art FIG. 14 shows an example of a camera incorporating a conventional focus detection device. In the figure, reference numeral 101 denotes an objective lens for reading a target image and performing photographing;
Is a translucent main mirror that partially reflects the image light beam from the objective lens 101, 103 is a reticle disposed at the focal position of the objective lens 101, 104 is a pentaprism that changes the light beam direction, 105 is an eyepiece, Reference numeral 106 denotes a submirror that operates at the time of focus detection, 107 denotes a film such as a silver halide film, and 108 denotes a focus detection device.

In FIG. 1, light from a subject (not shown) passes through an objective lens 101 and is partially reflected upward by a main mirror 102 to form an image on a focusing screen 103.
The image formed on the focusing screen 103 is a pentaprism 104
Is visually recognized by an observer or an observer via the eyepiece 105 through a plurality of reflections. The main mirror 1
The light transmitted through 02 reaches the film 107, and the target image can be obtained by exposing the image of the object.

On the other hand, from the objective lens 101 to the main mirror 10
A part of the light beam that has reached 2 passes through the main mirror 102, is reflected downward by the sub-mirror 106, and is guided to the focus detection device 108.

FIG. 15 is a view for explaining the principle of focus detection.
It is the figure which extracted and expanded only 08.

In the focus detection device 108 shown in FIG.
109 is a field mask arranged near the planned focal plane of the objective lens 101, that is, a plane conjugate to the film plane; 110 is a field lens also arranged near the planned focal plane;
Reference numeral 111 denotes a secondary imaging system including two lenses 111-1 and 111-2, and reference numeral 112 denotes a secondary imaging system arranged behind the two lenses 111-1 and 111-2 of the secondary imaging system 111 corresponding to the two lenses. A photoelectric conversion element including two sensor rows 112-1 and 112-2, and two lenses 11 of a secondary imaging system 111.
A stop having two apertures 113-1 and 113-2 arranged corresponding to 1-1 and 111-2, 114 is an objective lens 101 including two divided regions 114-1 and 114-2. The exit pupils are shown respectively. In addition, the field lens 110 sets the openings 113-1 and 113-2 of the stop 113 corresponding to the areas 114-1 and 114-2 of the exit pupil 114 of the objective lens 101. 1, 114-2, and has an action to form an image in the vicinity of the exit pupil 114.
The luminous fluxes 115-1 and 115-2 transmitted through 114-2 are 2
A light amount distribution is formed in each of the two sensor arrays 112-1 and 112-2.

A focus detection device 108 shown in FIG. 15 is generally called a phase difference detection system, and is used when the image forming point of the objective lens 101 is in front of a predetermined focal plane, that is, the objective lens 101 side. , Two sensor rows 112
When the light amount distributions formed on -1 and 112-2 are close to each other, and the image forming point of the objective lens 101 is behind the expected focal plane, the two sensor arrays 11
The light quantity distributions formed on 2-1 and 112-2 are separated from each other. Moreover, two sensor rows 112-
Since the shift amount of the light amount distribution formed on each of the lenses 1 and 112-2 has a certain functional relationship with the defocus amount of the objective lens 101, that is, the defocus amount, if the shift amount is calculated by an appropriate arithmetic unit, The direction and amount of defocus of the lens 101 can be detected. The position of the lens system is moved according to the direction of the defocus and the amount of defocus, the defocus amount is set to be substantially zero, and the focus detection operation ends.

[0008]

In a camera incorporating the conventional focus detection device 108 shown in FIG. 14, the focus detection area is narrow and one-dimensional as shown in FIG. Range. This is one set of line sensor arrays 112-1, 1-1 in the photoelectric conversion element 112.
It is determined by the detection device using 12-2.

FIG. 17 is a diagram for explaining the accumulation control of the sensor array 112. This is the two sensor rows 112
-1 and 112-2, the output (VD) of the light-shielded dark pixel 120 and the two sensor rows 112-1 and 1-1.
The difference between the output of the maximum value detection circuit 121 common to 12-2, that is, the output (VP) of the pixel indicating the maximum value,
2, storage is performed until the voltage reaches a predetermined level (VR). At the time of the arrival, the storage operation is completed, and ΦR, which is a read signal to the storage capacitor, is stored in the storage control unit 123.
Are sent to the sensor arrays 112-1 and 112-2. Here, the difference between the maximum value VP and the dark output VD is calculated based on the dark output VD by accumulating until the maximum value VP reaches a predetermined level VR. It can be determined that the level is of sufficient accuracy, and if the accumulation time is increased beyond the maximum value VP, the output signal is saturated and proper detection cannot be performed. ,
It returns to 112-2.

FIG. 18 shows two sensor arrays 112-1 and 112-1.
The state of the image signal 2-2 is shown with reference to the output VD of the dark pixel 120.
The maximum output value (VP, one image side in the figure) common to one image and two images, which are the respective image signals of −2, is set to a set level (V
R). Focus detection is performed for each sensor row 112-1,
One of the sensor pixels of 112-2 has the set level VR
Is reached, for example, the sensor pixels of each peak value are compared with a predetermined interval to determine whether or not the lens system including the objective lens is located at the focal position, and set to an appropriate focal position.

FIG. 19 schematically shows a circuit configuration after the maximum value detecting circuit 121. Each pixel output (n-th pixel output Vn) is compared with the current maximum value VP. If the n-th pixel output Vn exceeds the maximum value VP, the differential amplifier 130 is inverted and the MOS switch 132 is turned on. And the pixel output Vn is output via the voltage follower 131, and the pixel output Vn becomes the new maximum value VP. The maximum value VP output of the maximum value detection circuit 121 of each of the sensor arrays 112-1 and 112-2 is determined by the dark pixel output VD and the differential amplifier 1
At 33, the signal is amplified differentially and further compared with the set level VR by the comparator 134. When the differential output exceeds the set level VR, the accumulation is completed and the read signal ΦR is output. This read signal ΦR is output from the sensor array 112-1, 1
It becomes a signal for reading out the accumulated charge of each pixel 12-2.

On the other hand, FIG. 20 shows an example in which the focus detection area is enlarged. In the photographing screen A, three detection areas B are provided. This is obtained by adding three detection areas in the orthogonal direction to the detection area in FIG.

FIG. 21 shows an example in which the focus detection area shown in FIG. 20 is increased. In the figure, this is realized by using a photoelectric conversion element having a plurality of pairs of sensor rows C to F and a focus detection optical system (not shown) corresponding thereto.

In addition, as shown in FIG. 22, a dedicated accumulation control section is provided for each of the sensor arrays C, F, and peripheral circuits as shown in FIG. Are arranged by the number of sensor row pairs. In FIG. 22, each sensor row pair C to
F, the dark pixel outputs VD1 to VD4 and each sensor row pair C
To the maximum value output VP of the maximum value detection circuits 141 to 144
1 to VP4 are respectively obtained by differential amplifiers 145 to 148, and stored at predetermined levels VR by accumulation control units 149 to 152.
Is read out when a predetermined voltage is reached.
1 to ΦR4, and reads out the accumulated charge of each pixel of each sensor column pair CF. The common output of the accumulation control units 149 to 152 outputs a signal indicating the end of accumulation of each of the sensor arrays C to F to, for example, a control system including a CPU, and the control system detects that any of the sensor arrays has completed accumulation. Thereafter, the output of each pixel of each sensor row is read out as an image output, and the amount of defocus (the amount of defocus) is detected from this image output.

The above is a focus detecting device using a one-dimensional sensor array, that is, a line sensor. The detection area is a visual field corresponding to the light receiving section of each sensor array, and is not more than a combination of 'lines'.

Therefore, in order to further expand the detection area, a focus detection device using a photoelectric conversion element having a light-receiving portion that spreads two-dimensionally, that is, an area sensor is inevitably required.

FIG. 26 shows a detection area (B) with respect to a photographing screen A in a focus detection device using an area sensor. The detection area is greatly enlarged as compared with FIGS.

The photoelectric conversion element used for this area sensor is an area sensor pair G in which two area areas are arranged as shown in FIG. 27 if the phase difference detection method is performed.

The accumulation control for the area sensor pair G is a collective control over the entire area by the common dark pixel VD, the maximum value detection circuit 161, the differential amplifier 162, and the accumulation control unit 163 as shown in FIG. Here, for the sake of simplicity, it is assumed that an image signal Y for focus detection as shown in FIG. 26 is formed on the area sensor 171, and the area of the area sensor 171 is divided into four areas G to J as shown. Think separately.

FIG. 27 shows the state of image signals corresponding to each of the four regions G to J in FIG. As can be seen from the figure, since the entire area is controlled collectively, an appropriate accumulation state is established for the divided area H having the maximum output pixel in the area, but for the other divided areas G, I, and J. Results have been unsatisfactory. In this case, there is a problem that even if the detection area is expanded, the detectable area does not expand, and the use of the area sensor becomes meaningless.

Further, in the case of a conventional imaging apparatus using a line sensor, there is a problem of focus detection variation caused by the degree of application of an object image on a photoelectric conversion element row (so-called "phase-in / phase-out"). However, even if a two-dimensional area sensor is used, this phase i
There is a problem that the problem of n / phase out is not improved and still remains.

In the object image formed on the pair of area sensors for focus detection, the image is expanded two-dimensionally, so that the distortion of the image becomes large, and the focus detection mark on the finder deviates from the actual focus detection position. Or errors in focus detection. However, in order to improve the image distortion, a new member for optically correcting is needed, which is technically difficult and has additional problems such as a complicated configuration, which is an extremely difficult problem. It is.

[0023]

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems, and the gist is as follows. That is, over a wide range on the photographing screen or the observation screen, 2
In a focus detection device capable of detecting a focus two-dimensionally and continuously, a plurality of photoelectric conversion means having a continuous two-dimensional spread, which are light receiving units, are arranged such that adjacent photoelectric conversion element rows are in phase with each other with respect to an object image. Are displaced from each other, and the extent of the object image on the photoelectric conversion element row (so-called phase i
n / phase out), and the detection variation of the focus detection value caused by (n / phase out) is improved. Further, the photoelectric conversion means has a shape having a two-dimensional spread corresponding to the distortion of the object image.

More specifically, in the focus detection apparatus, the position of an object image formed by each of a pair of optical systems is formed on a photoelectric conversion element, and the object distance is detected by relatively comparing the positions. The elements are two-dimensionally spread by connecting a plurality of photoelectric conversion elements arranged one-dimensionally in the same direction as the direction in which the displacement of the object image occurs, while being displaced in accordance with the distortion of the object image. And adjacent photoelectric conversion element rows are arranged at positions different in phase from each other with respect to the object image. Also,
The focus detection device is characterized in that one focus detection value is obtained using outputs of the plurality of adjacent photoelectric conversion element arrays.

A focus detection device according to the present invention is a focus detection device in which a focus detection signal is obtained by a pair of area sensors having a photoelectric conversion element array, wherein the area sensor responds to distortion caused by an optical system. A row is arranged, the photoelectric conversion element rows are arranged at positions where the phases of the object images detected by the respective photoelectric conversion elements of the photoelectric conversion element rows adjacent to each other are different from each other, and the photoelectric conversion element row is a rectangle of the photoelectric conversion element. Are formed adjacent to each other on the long side, and the adjacent photoelectric conversion element rows are arranged so as to be shifted with respect to the short side of the rectangular shape of the photoelectric conversion element. Further, in the focus detection device, the arrangement of the photoelectric conversion elements shifted with respect to the short side of the rectangle is shifted by １ ／ of the short side.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] An embodiment according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an optical arrangement diagram of each component for performing focus detection in each region in a photographing screen. In the drawing, reference numeral 1 denotes an optical axis of an objective lens (not shown) disposed on the left side of the figure, 2 denotes a silver halide film disposed at a focal position of the objective lens, and 3 denotes an optical axis of the objective lens. The semi-transmissive main mirror 4 is also a first reflecting mirror obliquely arranged on the optical axis 1 of the objective lens.
Paraxial imaging plane conjugated to film 2 by reflecting mirror 4
Denotes a second reflecting mirror for focus detection, 7 denotes an infrared cut filter that blocks infrared rays, 8 denotes an aperture having two openings 8-1, 8-2, 9 denotes two apertures 8-1, 8 of the aperture 8. Secondary imaging system having two lenses 9-1 and 9-2 arranged corresponding to 8-2, 10 is a third reflecting mirror for focus detection, 11 is two area sensors 11-1, 11A and 11B each show a photoelectric conversion element having 11-2.

Here, the first reflecting mirror 4 has a curvature, and has a converging power for projecting the two apertures 8-1 and 8-2 of the stop 8 near the exit pupil of an objective lens (not shown). ing.
Further, the first reflecting mirror 4 has a metal film such as aluminum or silver deposited so as to reflect light only in a necessary area, and also functions as a field mask for limiting a range in which focus detection is performed.
In the other reflecting mirrors 6 and 10 as well, only a necessary minimum area is vapor-deposited in order to reduce stray light incident on the photoelectric conversion element 11. It is also effective to apply a light-absorbing paint or the like to a region that does not function as a reflection surface of each of the reflection mirrors 4, 6, and 10, or to provide a light-shielding member in close proximity.

FIG. 2 is a plan view of the stop 8, and has a configuration in which two horizontally long openings 8-1 and 8-2 are arranged in a direction in which the opening width is narrow. The dotted lines in the figure indicate the lenses 9-1 and 9-2 of the secondary imaging system 9 disposed behind the apertures 8-1 and 8-2 of the diaphragm 8 in correspondence with the apertures 8-1 and 8-2. It is.

FIG. 3 is a schematic plan view of the photoelectric conversion element 11, and the two area sensors 11-1 and 11- shown in FIG.
Reference numeral 2 denotes a two-dimensional array of pixels as shown in this figure, and two area sensors arranged at positions corresponding to an object image formed on the photoelectric conversion element.

FIG. 28 shows one area sensor 11- of FIG.
FIG. 2 is a diagram in which the area sensor shown in FIG. 1 is arranged in a configuration of a conventional area sensor. Reference numeral 23-1 denotes a photoelectric conversion element array that spreads two-dimensionally, and reference numeral 23-2 denotes distortion of an object image formed on the photoelectric conversion element array. The photoelectric conversion element array 23-1 is rectangular in a plane, and the rectangular elements are arranged vertically and horizontally. The object image 23-2 has a barrel shape due to the second and third order distortion of the lens system. There is distortion.

As shown in FIG. 28, the object image formed on the photoelectric conversion element expands two-dimensionally, thereby increasing the distortion of the image. In the vicinity of the focus detection area, the focus detection index and the actual focus detection The deviation from the position increases. Further, the problem of focus detection variation caused by the phase in / phase out between the photoelectric conversion element and the object image, which has been a problem in the past, has not been improved by the two-dimensional area sensor.

FIG. 4 shows the phase in /
It is a figure which shows the phase out, 20-1 shows one photoelectric conversion element row | line, 1 piece, and 20-2 has shown the object image on a photoelectric conversion element row | line. FIG. 6 is a graph of focus detection variation caused by the phase in / phase out of the object image on the photoelectric conversion element row. When the object image 20-2 in FIG. d, e,
The graph shows the position of the subject image at f on the horizontal axis and the output level of the element array on the vertical axis, and shows the change of the focus detection value depending on the position of each photoelectric conversion element. As can be seen from FIG. 6, the variation in the focus detection value caused by the phase in / phase out of the object image on the photoelectric conversion element row indicates a change with the width of the photoelectric conversion element as one cycle.

As means for improving the variation in focus detection caused by phase-in / phase-out and constantly enabling stable detection of the defocus amount, they are arranged as shown in FIG. In FIG. 5, the photoelectric conversion elements a to g in one line and the photoelectric conversion elements h to n in the other line are arranged in a relationship shifted by 素 子 element. FIG. 7 shows focus detection values obtained by the photoelectric conversion element array. In FIG. 7, the change 26-1 of the focus detection value indicated by the solid line by the photoelectric conversion elements h to n and the change 26-2 of the focus detection value indicated by the dotted line by the photoelectric conversion elements a to g in FIG. Is detected, and if they are simply added, the result becomes zero shown as 26-3. There is a method of arranging the photoelectric conversion element rows in a phase shifted relationship with each other, and calculating one focus detection value based on outputs of a plurality of adjacent photoelectric conversion element rows, and the phase difference between adjacent photoelectric conversion element rows is It has been clarified from the results of theoretical experiments that the relationship shifted by a half pitch of the photoelectric conversion element width has the greatest improvement effect.

However, the arrangement of adjacent photoelectric conversion element arrays shifted from each other by a predetermined amount has been filed many times (for example, Japanese Patent Application Laid-Open No. 59-105606). In contrast, simply shifting the adjacent photoelectric conversion element rows by a predetermined amount would cause the phase difference between the adjacent photoelectric conversion element rows and the object image between the adjacent photoelectric conversion element rows to differ from the predetermined amount due to distortion in the object image. However, a sufficient improvement effect cannot be obtained.

FIG. 9 shows a photoelectric conversion means according to an embodiment in which this problem is solved, and FIG. 10 is a partially enlarged view of FIG. Reference numeral 24-1 denotes a photoelectric conversion element, and 24-2 represents distortion of an object image on the photoelectric conversion element. FIG. 8 is an enlarged view of a part of the photoelectric conversion element array of FIG. 10, and the photoelectric conversion element array 27-2 adjacent to the photoelectric conversion element array 27-1 has a phase with respect to the object image 27-3 indicated by oblique lines. It is located at a shifted position. The phase of the object image 27-3 on the photoelectric conversion element row is shifted by a half pitch between adjacent lines of the photoelectric conversion element rows 27-1 and 27-2. The difference from FIG. 5 is that the photoelectric conversion means arranges a plurality of adjacent lines corresponding to the distortion of the object image, and is configured to have a phase shift between the adjacent lines with respect to the position of the luminous flux from the subject. It is characterized by.

Therefore, in the present embodiment, adjacent photoelectric conversion element rows are arranged so as to be shifted from each other by a predetermined pitch of the photoelectric conversion elements (half pitch in the present embodiment) with respect to the position of the light beam from the object, and are adjacent to each other. Even if the focus detection range is expanded by obtaining one focus detection value based on the defocus amount detected from the outputs of the plurality of photoelectric conversion element arrays, the influence of focus detection variation caused by phase in / phase out , And a stable defocus amount can always be detected.

In the above configuration, the light beams 12-1 and 12-2 from the photographing lens not shown in FIG. 1 pass through the main mirror 3, and then follow the inclination of the main mirror 3 by the first reflecting mirror 4. After being changed in direction again by the second reflecting mirror 6, each of the secondary imaging systems 9 passes through the infrared cut filter 7 and the two apertures 8-1 and 8-2 of the stop 8. Lens 9-
The light is condensed by 1 and 9-2 and reaches the area sensors 11-1 and 11-2 of the photoelectric conversion element 11 via the third reflecting mirror 10, respectively. The light fluxes 12-1 and 12-2 in the figure indicate light fluxes that form an image at the center of the film 2, but light fluxes that form an image at other positions pass through the same path to the photoelectric conversion element 11. Reached, overall, film 2
Two light quantity distributions corresponding to the above predetermined two-dimensional area are formed on each of the area sensors 11-1 and 11-2 of the photoelectric conversion element 11.

In this embodiment, the first reflecting mirror 4 is
It is composed of a part of a curved surface formed by rotating a quadratic curve around an axis, and a spheroid is particularly preferably used. In FIG. 1, the surface shape of the first reflecting mirror 4 is a part of a spheroid formed by rotating an ellipse 21 having a point 20 as a vertex around an axis 22, and its focal point is the second reflection. The vicinity of the image position 23 at the center of the stop 8 by the mirror 6 and the translucent main mirror 3
Is set in the vicinity of a point (not shown) on the extension of the optical axis 24 after transmission. If the point on the extension of the optical axis 24 is focused near the exit pupil position of the objective lens (or the average exit pupil position when various objective lenses are used interchangeably), the objective lens The exit position and the incident position of the secondary imaging system are substantially imaged, and the first reflecting mirror 4 functions as an ideal field lens. As is clear from FIG. 1, what is optically used as the first reflecting mirror 4 is a region not including the rotation axis and the vertex of the spheroid.

In this embodiment, the secondary imaging system 9 is used.
Has a concave surface on the first side on the incident side, so that light incident on the secondary imaging system 9 is not forcibly refracted. And good and uniform imaging performance over a wide range.

With respect to the two light quantity distributions thus obtained, the separation direction, that is, the two area sensors 1 shown in FIG.
By calculating the relative positional relationship between 1-1 and 11-2 in the vertical direction at each position of the area sensors 11-1 and 11-2, the focus state of the objective lens can be detected two-dimensionally. .

Incidentally, the first reflecting mirror 4 is retracted out of the optical path for photographing, like the main mirror 3, when photographing on the silver halide film 2.

Next, the photoelectric conversion element 11 will be described in detail. FIG. 11 illustrates the distribution of the focus detection areas in the present embodiment as viewed from the finder of the camera. As shown in the figure, in the present embodiment, a total of 55 areas (11 in the left and right and 5 in the upper and lower areas) are arranged at the center of the shooting screen 31 (in the figure,
Represents one area). This 55
The two area sensors 11-1 and 11-2 of the photoelectric conversion element 11 are divided into 55 so as to correspond to each of the divided areas. 55 divided areas viewed from this finder are
In FIG. 9, each of the photoelectric conversion element rows 11-1 and 11-2 is divided into 55 divided areas, and one of the photoelectric conversion element rows 11-1 shown in FIG. 10 is also divided into 55 divided areas. The photoelectric conversion element rows 11-1 are arranged along the distortion of the system, and the adjacent photoelectric conversion elements are separated from each other by １ ／.
It is shifted by pixels. Thus, the phase in / phase ou generated when the focus is detected by the area sensor.
The focus detection variation due to t can be significantly reduced and improved.

Next, an example of a focus detecting device using an area sensor of a 5 × 3 area shown in FIG. 12 will be described. 12 in FIG. 12 is 1
FIG. 10 is a view showing a region as viewed from the viewfinder of the camera, and a photoelectric conversion element array corresponding to this state is shown in FIG. 9;
The output processing circuit is configured so as to obtain the focus detection signal from the region.

[Second Embodiment] FIG. 13 is a circuit diagram showing an example of a specific configuration of a camera provided with each of the focus detection devices as described above. First, the configuration of each section will be described.

In FIG. 13, PRS is a camera control device, for example, a CPU (central processing unit), RO
This is a one-chip microcomputer having M, RAM, A / D, and D / A conversion functions. The microcomputer PRS performs a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, and film winding / rewinding in accordance with a camera sequence program stored in the ROM. For this purpose, the microcomputer PRS communicates with the peripheral circuit in the camera body and the control device in the lens using the communication signals SO, SI, SCLK, and the communication selection signals CLCM, CDDDR, CICC.
It controls the operation of each circuit and lens.

SO is the data signal output from the microcomputer PRS, and SI is the microcomputer PR
A data signal input to S, SCLK is a signal SO, SI
Is a synchronous clock.

LCM is a lens communication buffer circuit,
When the camera is in operation, power is supplied to the lens power supply terminal VL, and a selection signal CLCM from the microcomputer PRS is abbreviated as a high potential level (hereinafter abbreviated as “H”, and a low potential level is abbreviated as “L”). )
It becomes a communication buffer between the camera and the lens.

The microcomputer PRS outputs the selection signal C
When the LCM is set to “H” and predetermined data is transmitted from the data signal SO in synchronization with the synchronization clock SCLK, the lens communication buffer circuit LCM outputs the synchronization clock SCLK and the data signal SO via the camera-lens communication contact. The respective buffer signals LCK and DCL are output to the lens.
At the same time, a buffer signal of the signal DLC from the lens LNS is output to the data signal SI, and the microcomputer PRS inputs lens data from the data signal SI in synchronization with the synchronization clock SCLK.

DDR is a circuit for detecting and displaying various switches SWS, is selected when the signal CDDR is "H", and is controlled by the microcomputer PRS using the data signals SO, SI and the synchronous clock SCLK. That is, based on data sent from the microcomputer PRS, the display of the display member DSP of the camera is switched, and the on / off state of various operation members of the camera is notified to the microcomputer PRS by communication. OLC
Is an external liquid crystal display device located at the top of the camera, IL
C is a finder internal liquid crystal display device. In the present embodiment, the setting of the focus detection operation area and the like are performed by the switch SWS belonging to the detection and display circuit DDR.

SW1 and SW2 are switches linked to a release button (not shown). SW1 is turned on when the release button is pressed in the first stage, and SW2 is subsequently turned on when pressed in the second stage. Microcomputer PRS is SW
Photometry and automatic focus adjustment are performed when 1 is turned on, and exposure control and subsequent film winding are performed using SW2 as a trigger.

The switch SW2 is connected to the "interrupt input terminal" of the PRS, which is a microcomputer. Even when the program is executed when the switch SW1 is turned on, an interrupt is generated by turning on the switch SW2, and the control can be immediately transferred to a predetermined interrupt program.

MTR1 is a motor for feeding the film, and MTR2 is a motor for mirror up / down and charging of the shutter spring. The normal rotation and the reverse rotation are controlled by respective drive circuits MDR1 and MDR2. Microcomputer P
Signals M1F, M1R, M2F, and M2R input from the RS to the drive circuits MDR1 and MDR2 are forward and reverse control signals for motor control.

MG1 and MG2 are magnets for starting the movement of the first and second curtains of the shutter, and control signals SMG1 and SMG.
2. Energized by the amplification transistors TR1 and TR2,
Shutter control is performed by the microcomputer PRS.

The motor drive circuits MDR1, MDR
2. Since shutter control is not directly related to the present invention,
Detailed description is omitted.

A buffer signal DCL input to the control circuit LPRS in the lens LNS in synchronization with the buffer signal LCK.
Is data of an instruction from the camera to the lens LNS, and the operation of the lens LNS for the instruction is predetermined. The control circuit LPRS in the lens LNS analyzes the command in accordance with a predetermined procedure, and performs an operation of focus adjustment and aperture control, an operation status of each part of the lens LNS from the output DLC (a drive status of the focus adjustment optical system, a drive status of the aperture, and the like). ) And various parameters (open F number, focal length, coefficient of defocus amount vs. movement amount of focus adjustment optical system, various focus correction amounts, etc.).

This embodiment shows an example of a zoom lens. When a focus adjustment command is sent from the camera, the focus adjustment motor LMTR is sent to the signals LMF and LMF in accordance with the drive amount and direction sent at the same time. Driven by the LMR, the optical system is moved forward and backward in the optical axis direction to perform focus adjustment. The amount of movement of the optical system is monitored by a pulse signal SENCF of an encoder circuit ENCF that detects a pattern of a pulse plate that rotates in conjunction with the optical system with a photocoupler and outputs a number of pulses corresponding to the amount of movement. The count is performed by a counter in the control circuit LPRS in the LNS. When the predetermined movement of the front lens of the lens is completed, the control circuit LPRS in the lens LNS sets the signals LMF and LMR to “L” to brake the motor LMTR. .

For this reason, once the focus adjustment command is sent from the camera, the microcomputer PRS, which is the control device of the camera, does not need to be involved in driving the lens at all until the driving of the lens is completed. Further, when a request is received from the camera, the contents of the counter can be transmitted to the camera.

When an aperture control command is sent from the camera, a known stepping motor DMTR for driving the aperture is driven in accordance with the number of aperture stages sent at the same time. Since the stepping motor DMTR can perform open control, it does not require an encoder for monitoring the operation.

ENCZ is an encoder circuit associated with the zoom optical system, and the control circuit LPRS in the lens LNS receives the signal SENCZ from the encoder circuit ENCZ to detect the zoom position. Control circuit LPR in lens LNS
In S, lens parameters at each zoom position are stored, and the microcomputer PRS on the camera side
Sends a parameter corresponding to the current zoom position to the camera.

The ICC is a focus detection area sensor composed of a CCD or the like as a photoelectric conversion element and a focus detection circuit as a drive control circuit thereof. The ICC is selected when the selection signal CICC is "H" and the data signal is selected. It is controlled from the microcomputer PRS using SO, SI, and the synchronization signal SCLK.

ΦV, ΦH and ΦR are area sensor output reading and reset signals.
A sensor control signal is generated by a drive circuit in the focus detection circuit ICC based on the signal from the RS. The sensor output is amplified after reading from the sensor unit, and the output signal IMAGE is output.
Is input to the analog input terminal of the microcomputer PRS, and the microcomputer PRS outputs the output signal I.
After A / D conversion of the MAGE, the digital value is sequentially stored at a predetermined address on the RAM. Focus detection is performed using these digitally converted signals.

VR is an accumulation end determination level common to the above-described differential amplifiers, INT is an accumulation end output signal,
ICLK is a reference clock signal of a control circuit section in the focus detection circuit ICC.

In the entire camera system described above, especially the operation of the focus detection circuit ICC performs the operation of focus detection by each area sensor as described in the first embodiment, and the result is transmitted via the microcomputer PRS. Lens L
The in-NS control circuit LPRS moves and holds the lens system at an appropriate focal point, and then operates the shutter, so that a focused image can be obtained.

In FIG. 13, the camera and the lens LNS are used.
Are represented as separate bodies (lenses can be exchanged), but the present invention is not limited to these without any problem even if the camera and lens are integrated.

In the above embodiment, the incident light from the photographing lens is separated into two images having two parallaxes before forming an image on the area sensor. Two images incident through two lenses may be incident on each area sensor.

[0066]

According to the present invention described above, in a focus detection device which performs focus detection two-dimensionally and continuously over a wide range on a photographing screen or an observation screen, between adjacent photoelectric conversion element rows. By disposing them at positions shifted from each other in phase with the object image and performing focus detection based on the focus detection information of a plurality of adjacent photoelectric conversion element rows, distortion of the object image formed on the photoelectric conversion element can be reduced. Without the need for correction, it is possible to improve focus detection variations caused by phase-in / phase-out and always perform stable focus detection.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a focus detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an aperture and a secondary imaging system according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a photoelectric conversion element according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an object image on a conventional photoelectric conversion element array.

FIG. 5 is a view showing an object image on a photoelectric conversion element row of the present invention.

FIG. 6 is a diagram illustrating a change in a focus detection value due to phase in / phase out.

FIG. 7 is a diagram illustrating a change in a focus detection value due to phase in / phase out for explaining the present invention.

FIG. 8 is a diagram showing a distortion of a subject image and an enlarged part of the area sensor of the present invention.

FIG. 9 is a diagram illustrating distortion of an object image according to the present invention and element arrangement of the entire area sensor according to the embodiment of the present invention.

FIG. 10 is a diagram illustrating distortion of an object image according to the present invention and element arrangement of an area sensor according to the embodiment of the present invention.

FIG. 11 is a diagram showing a distribution of focus detection areas according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating functions of the photoelectric conversion element according to the embodiment of the present invention.

FIG. 13 is a circuit diagram of a camera and a lens according to an embodiment of the present invention.

FIG. 14 is a layout diagram of a conventional focus detection device in a camera.

FIG. 15 is a diagram illustrating a conventional focus detection device.

FIG. 16 is a diagram showing a distribution of a conventional focus detection area.

FIG. 17 is a diagram illustrating a conventional photoelectric conversion element and its accumulation control.

FIG. 18 is a diagram illustrating a conventional photoelectric conversion element and its accumulation control.

FIG. 19 is a diagram illustrating a conventional photoelectric conversion element and its accumulation control.

FIG. 20 is a diagram showing a conventional distribution of focus detection areas.

FIG. 21 is a diagram illustrating a conventional photoelectric conversion element and its accumulation control.

FIG. 22 is a diagram illustrating a conventional photoelectric conversion element and its accumulation control.

FIG. 23 is an explanatory diagram of a case where a focus detection area is two-dimensionally enlarged by a conventional method.

FIG. 24 is an explanatory diagram in a case where a focus detection area is two-dimensionally enlarged by a conventional method.

FIG. 25 is an explanatory diagram in a case where a focus detection area is two-dimensionally enlarged by a conventional method.

FIG. 26 is an explanatory diagram in a case where a focus detection area is two-dimensionally enlarged by a conventional method.

FIG. 27 is an explanatory diagram of a case where a focus detection area is two-dimensionally enlarged by a conventional method.

FIG. 28 is a diagram showing distortion of an object image and element arrangement of a conventional area sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical axis of objective lens 2 Film 3 Main mirror 4 First reflecting mirror 5 Image forming surface 6 Second reflecting mirror 7 Infrared cut filter 8 Aperture 9 Secondary imaging system 10 Third reflecting mirror 11 Photoelectric conversion element Reference Signs List 12 light flux 24 optical axis of objective lens 31 shooting screen area 101 objective lens 102 main mirror 103 focusing screen 104 pentaprism 105 eyepiece 106 submirror 107 film 108 focus detection device 109 field mask 110 field lens 111 secondary imaging system 112 photoelectric conversion Element 113 Aperture 114 Exit pupil of objective lens 115 Light flux A Imaging screen area B Focus detection area Microcomputer PRS In-camera control device LCM Lens communication buffer circuit SDR Sensor drive circuit LNS lens L Microcomputer PRS In-lens control circuit ENCF Focus adjustment Encoder for detecting the movement of the joint lens

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichiro Yamashita 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshifumi Otaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Non Corporation

Claims (4)

[Claims] 1. A focus detection device that forms a position of an object image formed by each of a pair of optical systems on a photoelectric conversion element and detects a subject distance by relatively comparing the positions, wherein the photoelectric conversion element is A plurality of photoelectric conversion elements which are arranged one-dimensionally in the same direction as the direction in which the displacement of the object image occurs, are connected two-dimensionally while being displaced in accordance with the distortion of the object image, and have a two-dimensional spread. A focus detection apparatus, wherein adjacent and adjacent photoelectric conversion element arrays are arranged at positions different in phase from each other with respect to the object image. 2. The focus detection apparatus according to claim 1, wherein one focus detection value is obtained using outputs of the plurality of adjacent photoelectric conversion element arrays. 3. A focus detection device that obtains a focus detection signal by a pair of area sensors including a photoelectric conversion element array, wherein the area sensor arranges the photoelectric conversion element array according to distortion caused by an optical system, and Each of the photoelectric conversion elements adjacent to each other is arranged at a position where the phase of the object image detected by each photoelectric conversion element of the photoelectric conversion element is different, and the photoelectric conversion element rows are adjacent to each other on a long side of a rectangle of the photoelectric conversion element. A focus detecting device, wherein the adjacent photoelectric conversion element rows are arranged so as to be shifted with respect to a short side of a rectangle of the photoelectric conversion element. 4. The focus detection device according to claim 3, wherein the arrangement of the photoelectric conversion elements shifted with respect to the short side of the rectangle is a half of the short side.