JPH11281877A - Focus position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the focus position detecting device which can put a used lens in focus on an object or the part of the object with range finding precision corresponding to the full-aperture F value of the used lens. SOLUTION: The focus position detecting device is provided with 1st range finding sensor groups 146a to 146d having short base length corresponding to pieces 30A and 30B of luminous flux passing through a pupil 30 with a 1st full-aperture F value (e.g. F6.7) of an image pickup optical system 201 and 2nd range finding sensor groups 246a to 246d having long base length corresponding to pieces 50A and 50B of luminous flux passing through a pupil 50 with a 2nd full-aperture F value (e.g. F2.8) of the image pickup optical system 201 in order to put the lens in focus on the same object at the center part of an image plane or the same part of the object; when an image pickup optical system having a full-aperture F value smaller than the 2nd full-aperture F value is mounted, the image pickup optical system is put in focus by using the 1st range finding sensor groups 146a to 146d and 2nd range finding sensor groups 246a to 246d are when an image pickup optical system which has a full-aperture F value larger than the 2nd full-aperture F value is mounted, the image pickup optical system is out in focus by using the 1st range finding sensor groups 146a to 146d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a focus position detecting device of an image pickup optical system used for an AF single-lens reflex camera or the like.

[0002]

2. Description of the Related Art A basic configuration of a focus position detecting device conventionally used in an AF single-lens reflex camera or the like will be described with reference to FIGS. As shown in FIG. 21, the focal position detecting device 20 is provided behind the planned focal plane 11 of the imaging optical system 10, and includes a condenser lens 21 for condensing a light beam that has passed through the imaging optical system 10, and an aperture mask. 22
Focus position by detecting the relative positional relationship between the re-imaging lens 23, the photoelectric conversion element array 24 such as a CCD line sensor, and the two subject images formed on the photoelectric conversion element array 24. And an arithmetic circuit 25 for calculating the amount of deviation and the direction of deviation.

When the focus position of the image pickup optical system 10 matches the subject, that is, when the subject is in focus, the distance between the two subject images formed on the photoelectric conversion element array 24 is constant (when the focus is attained). The distance between the two subject images in the case of the so-called front focus is narrower than L0, while the distance between the two subject images in the case of the so-called rear focus is wider than L0. Therefore, by detecting the distance between the two subject images on the photoelectric conversion element array 24, it is possible to know whether the object is in focus or out of focus, and in the out of focus state, it is possible to know the amount and direction of defocus.

An AF single-lens reflex camera is equipped with a lens having an image pickup optical system having various focal lengths and an open F value (an interchangeable lens as a completed product including an image pickup optical system, an aperture mechanism, and an image pickup optical system extension mechanism). can do. FIG.
2, the open F value as indicated by the solid line is F2.8 or F
4 and the like, the open F-number as shown by the one-dot chain line is smaller than that in the case of using the small (bright) imaging optical system 10a such as F4.
6, a large (dark) imaging optical system 10 such as F6.7
When b is used, the cross-sectional diameter of the light beam from the subject reaching the position of the aperture mask 22 (the diameter of the pupil of the imaging optical system) is smaller. Therefore, the positions of the pair of openings 22a of the aperture mask 22 correspond to the imaging optical system having the largest open F-number (for example, F6.7) so as to correspond to all the interchangeable lenses usable in this camera. It is provided in.

On the other hand, when the focal length is the same, an imaging optical system having a smaller open F-number has a smaller depth of field and requires higher focusing accuracy. The relationship between the base line length of a distance measuring sensor composed of an aperture mask, a re-imaging lens, a photoelectric conversion element array, and the like and the distance measuring accuracy will be described with reference to FIG. In FIG. 23, F is the film surface, L is the optical axis, O is the intersection of the optical axis L and the film surface F, P is the position of the image on the optical axis, D is the defocus amount, and d1 and d2 are the defocus amounts, respectively. The amount of movement of the image on the photoelectric conversion element array with respect to D, R1, R
1 ', R2 and R2' are re-imaging lenses, S1 and S1 'are islands constituting a photoelectric conversion element array (distance measuring sensor) having a base length T1, and S2 and S2' are base lengths T.
2 shows islands constituting a photoelectric conversion element array of 2 (T2> T1).

[0006] Assuming that an object on the optical axis is imaged at a point P by an imaging optical system (not shown), the light flux passing through the point P is re-imaged by lenses R1, R1 ', R2, and R2'. Incident on the islands S1, S1 ', S2 and S2'. Next, when the image of the object moves to the point O by moving the imaging optical system, the images move by d1 on the islands S1 and S1 ′ close to the optical axis L, and move to the island S1 away from the optical axis L.
On 2 and S2 ', the image moves by d2 (d2> d1). That is, assuming that the defocus amount D is constant, the further the island of the photoelectric conversion element is from the optical axis, the larger the amount of movement of the image thereon. Further, assuming that the size of the pixel of each island is constant, the focus detection accuracy is higher when using the islands S2 and S2 ′ remote from the optical axis L than when using the islands S1 and S1 ′ closer to the optical axis L. Get higher. That is, the longer the base line length of the distance measuring sensor, the higher the focus detection accuracy.

[0007]

However, the conventional focus position detecting apparatus is compatible with an imaging optical system having the largest open F value (smallest pupil diameter) among the interchangeable lenses that can be used, and an aperture mask. The aperture 22a, the re-imaging lens 23, the photoelectric conversion element array 24, and the like are areas where a light beam transmitted through the pupil of the imaging optical system having the largest open F value can reach (a relatively narrow area near the optical axis). Is located within. Therefore, there is a certain limit in the base line length of the distance measuring sensor including the aperture mask 22, the re-imaging lens 23, the photoelectric conversion element array 24, and the like.

When a lens having an imaging optical system with a small open F value (large pupil diameter) is mounted on an AF single-lens reflex camera or the like using a conventional focus position detecting device, a light beam transmitted through a pupil of the imaging optical system is generated. Although the reachable area is wide and the base line length of the distance measuring sensor can be lengthened, the distance must be measured with a distance measuring sensor having a short base line length. However, there is a problem that it is not possible to obtain a distance measurement accuracy suitable for the measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem of the prior art, and has a focus position detection method capable of focusing on a subject with a distance measurement accuracy corresponding to the open F-number of an imaging optical system of a lens to be used. It is intended to provide a device.

[0010]

In order to achieve the above-mentioned object, a focus position detecting apparatus according to the present invention is provided in a first range in which a light beam from a subject can reach by a first open F-number imaging optical system. A first distance measurement sensor group including a first cross sensor that is provided and includes two distance measurement sensors arranged orthogonal to each other, and a second open F value smaller than the first open F value. A second ranging sensor including a second cross sensor including two ranging sensors provided in a second region where a light beam from the subject can reach by the imaging optical system and arranged orthogonal to each other. And an imaging optical system using the first distance measurement sensor group and the second distance measurement sensor group when the second open F value and an image pickup optical system having a smaller open F value are mounted. The focusing operation of the system is performed, and an opening F value larger than the second opening F value is set. The If the image optical system is attached 1
The focusing operation of the imaging optical system is performed using the distance measurement sensor group.

For example, assuming that the first open F value is F6.7 and the second open F value is F2.8, the open F value is F2 or F2.
When an imaging optical system having a shallow depth of field with an aperture value near the open F value such as 8 or the like is mounted, the distance measuring sensors of both the first distance measuring sensor group and the second distance measuring sensor group are used. Since the luminous flux from the subject arrives, the focusing operation is performed using all the distance measurement sensor groups. On the other hand, when an imaging optical system having an open F value larger than the second open F value, such as F4 or F5.6, is mounted, the luminous flux from the subject is applied to the second distance measurement sensor group. Does not arrive, the focusing operation of the lens is performed using the first ranging sensor group. In the latter case, which is the same as the conventional example, in the former case, the focal point of the imaging optical system is focused on the subject by using the second distance measuring sensor group having a longer base line provided at a position further away from the center of the screen. The focusing operation can be performed, and a focusing operation with high ranging accuracy can be performed.

Further, the first cross sensor and the second cross sensor may both be arranged around the optical axis of the imaging optical system, and may be arranged so as to form a certain angle with each other. . Further, the second ranging sensor group may be provided at a position farther from the optical axis of the imaging optical system than the first ranging sensor group. Further, the first distance measurement sensor group and the second distance measurement sensor group may each include a photoelectric conversion element array, and each photoelectric conversion element array may be formed on the same chip. Further, the first distance measurement sensor group and the second distance measurement sensor group further include a re-imaging lens group, and the four first distance sensors correspond to the first cross sensor.
Are arranged integrally and radially around the optical axis of the imaging optical system, and the four second re-imaging lens groups corresponding to the second cross sensor group are arranged in the imaging optical system. May be arranged so as to be radially dispersed outside the first re-imaging lens group about the optical axis of. According to these configurations, the first distance measuring sensor and the second distance measuring sensor can be integrated into one chip, and it is possible to reduce the size of the device and reduce assembly errors.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a focus position detecting device according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 shows a configuration example of an AF single-lens reflex camera in which each embodiment of the focus position detection device of the present invention is used.

At the substantially center of the camera body 100, a main mirror 111 is provided at an angle of about 45 degrees with respect to the optical axis L, and is provided on the back of the main mirror 111. A mirror box 110 having a mirror 112 and the like is provided. Mirror box 1
A finder 120 including a reticle 121, a prism 122, an eyepiece 123, a display element 124, and the like is provided on an upper part of the apparatus 10. A light emitting unit 1 for emitting a flash light is provided above the finder 120.
70 are provided.

At the bottom of the mirror box 110 (the side opposite to the finder 120), there are provided a focus position detecting device 140, a light control sensor 150, an AF drive unit 160, and, if necessary, a relay lens 151 and the like. A shutter unit 130 is provided between the rear surface of mirror box 110 (the side opposite to lens 200) and film surface 1. The flexible printed circuit board 300 provided with the AFCPU 301 and the wiring 302 is provided in a gap or the like of the camera body 100.

The lens 200 includes an imaging optical system 201, a lens barrel 202 holding the imaging optical system 201, a lens driving mechanism 203 for driving the lens barrel 202 in a direction A parallel to the optical axis L, a focal length of the lens, and an F-number. (Open F value, open F value for AF, minimum F value, etc.)
A lens CPU 204 for outputting to the PU 301 is provided. In the following description of each embodiment, the lens 2
00 is the first open F-number (for example, F
6.7) has an open F-number equal to or less than
Enable auto focus.

Note that the open F value for AF is an open F value used for automatic focus adjustment, and does not always match the actual open F value of the image pickup optical system. For example, 50mm /
With a lens of F2.8, the open F value for AF is F5.6.
Is used. Therefore, the first open F value and the second open F value of the imaging optical system are broad concepts including both the open F value of the imaging optical system and the open F value for AF.

The main mirror 111 reflects a large part of the light beam from the imaging optical system 201 in the direction of the reticle 121 and transmits the remaining part. The auxiliary mirror 112 guides the light beam transmitted through the main mirror 111 to the focal position detection device 140. The prism 122 reverses the left and right of the image on the focusing screen 121 and guides the image to the photographer's eye via the eyepiece lens 123.

A photometric unit 180 is provided near the exit surface of the prism 122. Photometric unit 180
Includes a condenser lens and a photoelectric conversion element such as a photodiode, and outputs a signal corresponding to the luminance of the subject 2 to the AFCPU 3.
Output to 01. The display element 124 includes a light-emitting element such as a light-emitting diode, a liquid crystal display element, and the like, and displays a state in which the lens is focused on the subject 2 (focused state), a shutter speed, an aperture value of the lens, and the like.

The light emitting unit 170 includes a capacitor (not shown) for storing light emitting energy, a charging circuit (not shown) for charging the capacitor, and discharges electric energy stored in the capacitor to light energy. An arc tube 171 for conversion, a reflector 172 for reflecting flash light from the arc tube 171 forward of the camera, and a Fresnel lens 17 for condensing or diffusing the flash light in a predetermined range.
3 and so on. The light control sensor 150 includes, for example, a photoelectric conversion element such as a condenser lens and a photodiode, detects light reflected from the film 1 during emission of flash light by the light emitting unit 170, and outputs a signal corresponding to the amount of light to the AF CPU 301. Output to When the AF CPU 301 determines that the exposure amount of the film 1 has reached a predetermined value based on a signal from the light control sensor 150, the light emitting unit 17
Light emission of 0 is stopped.

The AF drive unit 160 includes an actuator such as a DC motor, a stepping motor, or an ultrasonic motor, an encoder that detects the rotation direction and the number of rotations of the actuator and outputs the detected signal to the AF CPU 301, and a deceleration for reducing the number of rotations of the actuator. It includes a system (not shown) and is connected to the lens driving mechanism 203 via the output shaft 161. The lens driving mechanism 203 is composed of, for example, a helicoid and a gear (not shown) for rotating the helicoid, and integrally drives the imaging optical system 201 and the lens barrel 202 in the direction of the arrow A by the driving force of the actuator of the AF driving unit 160. Move to The moving direction and the moving amount of the imaging optical system 201 and the lens barrel 202 follow the rotation direction and the rotation speed of the actuator, respectively.

(First Embodiment) A first embodiment of a focus position detecting device according to the present invention will be described with reference to FIGS.

In the focus position detection device 140 shown in FIG. 2, the field mask 141 is provided near a position where the distance from the imaging optical system 201 is relatively equal to that of the film 1. Of the light beams, the light beam incident on the focus position detection device 140 is restricted. The field mask 141 has five openings 141a to 141 corresponding to the respective distance measurement areas 31 to 34, 41, and 42 (see FIG. 3) described later.
1e.

Behind the field mask 141, there is provided a condenser lens 142 in which five condenser lens groups 142a to 142e corresponding to the openings 141a to 141e of the field mask 141 are integrated. Further, a mirror 143 is provided behind the condenser lens 142, and the luminous flux transmitted through the field mask 141 and the condenser lens 142 is converted into an aperture mask 144 having a plurality of apertures.
Lens array 145 integrating a plurality of re-imaging lens groups
And a plurality of photoelectric conversion element array groups are made incident on a detection element 146 integrated therewith.

Further, the field mask 141, the condenser lens 142, the mirror 143, the aperture mask 144, the lens array 145, and the detection element 146 are integrally connected to a frame (not shown) and are modularized. The aperture mask, the re-imaging lens, and the photoelectric conversion element array corresponding to each of the distance measurement areas 31 to 34, 41, and 42 constitute a distance measurement sensor. The same applies to the following embodiments.

In the case of the first embodiment, in order to realize the optimum ranging accuracy in accordance with the open F-number of the imaging optical system 201 of the mounted lens 200, for example, the first lens is placed at the center of the screen in FIG. The first F value corresponding to the open F value (eg, F6.7)
Among the distance measurement area groups 31 to 34, the distance measurement area groups 31 and 32 (first cross sensor) parallel to the screen in the vertical direction and the horizontal direction, respectively, and the second open F value (for example, F2.8). Second distance measurement area groups 41 and 42 corresponding to each other and forming substantially 45 degrees (hatched) with respect to the vertical direction or the horizontal direction of the screen.
(The second cross sensor).

Each of the first ranging area groups 31 to 34 is a range in which a light beam (hereinafter, referred to as a ranging light beam) from a subject passing through a pupil of the imaging optical system 201 having the first open F value can reach. Is set within. In the first ranging area group,
The distance measurement areas 33 and 34 are used for focusing on a subject or a part of the subject located away from the center of the screen.

The first ranging sensor group corresponding to the first ranging area groups 31 to 34 is always used regardless of the open F value of the imaging optical system 201 of the lens 200 mounted. The second ranging sensor group corresponding to the second ranging area groups 41 and 42 has an opening F value equal to or smaller than the second opening F value (for example, F1.4, F2, F2.8
Etc.) are used only when the lens 200 having the imaging optical system 201 is mounted. As is clear from FIG. 3, the first ranging area groups 31 to 34 and the second ranging area groups 41 and 42 are formed by dividing the screen into approximately three equal parts in the vertical and horizontal directions, respectively. It is provided in the central area of the nine areas.

The aperture mask 144 in the first embodiment
FIGS. 4 to 6 show the arrangement of the aperture, the re-imaging lens of the lens array 145, and the photoelectric conversion element array of the detection element 146, respectively. As is clear from FIG. 6, the first cross sensor constituted by the first distance measurement area groups 31 and 32 has two symmetrical points on the horizontal axis H passing through the center of the screen and symmetrical with respect to the center of the screen. It comprises photoelectric conversion element arrays 146a and 146b and two photoelectric conversion element arrays 146c and 146d on the vertical axis V and symmetric with respect to the center of the screen. Similarly, the second cross sensor constituted by the second distance measurement area groups 41 and 42 is symmetrical with respect to the center of the screen on a line substantially 45 degrees with respect to the horizontal axis H or the vertical axis V, respectively. Four photoelectric conversion element arrays 246a and 246
b, 246c and 246d. The distance measuring sensor groups corresponding to the other first distance measuring area groups 32 and 34 also have two photoelectric conversion element arrays 146e and 146e, respectively.
46f, 146g and 146h. The openings 144a to 144f and 244a to 244d of the aperture mask 144 and the re-imaging lenses 145a to 145h and 245 of the lens array 145 correspond to the structure of the photoelectric conversion element array.
a to 245d are also arranged symmetrically with respect to the center of the screen, the vertical axis V or the horizontal axis H. In particular, the first of the lens array 145
Distance measuring area groups 31 and 32 constituting the cross sensor of FIG.
The first re-imaging lens groups 145a to 145d corresponding to
Are radially integrated with the screen center or the optical axis of the imaging optical system 201. Further, the second re-imaging lens groups 245a to 245d corresponding to the second ranging area groups 41 and 42 constituting the second cross sensor are located outside the first re-imaging lens groups 145a to 145d. Radially dispersed around the optical axis of the imaging optical system 201.

FIG. 7 shows how the light beam for distance measurement that has passed through the pupil of the image pickup optical system 201 reaches the photoelectric conversion element array of the detection element 146. In order to simplify the illustration, the field mask 141, the mirror 143, the aperture mask 14
4 and the re-imaging lens (lens array) 145 are omitted. In the drawing, F represents a film surface.

Of the luminous flux emitted from the subject or the portion of the subject in a random direction and incident on the imaging optical system 201 of the lens 200, the luminous flux having passed through the inner region of the pupil 30 of the imaging optical system having the first open F-number. 30A and 30B advance as indicated by a dashed line in the figure, and reach distance measuring sensors (photoelectric conversion element arrays) 146c and 146d corresponding to the first distance measuring area (group) 32 in FIG. System 2
01, the second focusing area group 4
It does not reach the second distance measuring sensors (photoelectric conversion element arrays) 246a to 246d corresponding to 1 and 42. Similarly,
A region radiated from the subject or a part of the subject and located outside the pupil 30 of the imaging optical system having the first open F value and within the pupil 50 of the imaging optical system having the second open F value (off-axis of the imaging optical system) part)
The light fluxes 50A and 50B that have passed through the optical path travel as indicated by the solid lines in the figure, and the second distance measurement sensors (photoelectric conversion element arrays) 246c and 246 corresponding to the second distance measurement area (group) 42.
reaches d. These light beams 50A and 50B also reach first distance measurement sensors (photoelectric conversion element arrays) 146a to 146d corresponding to the first distance measurement area groups 31 and 32.

Accordingly, the open F value of the imaging optical system 201 of the mounted lens 200 is equal to the second open F value (for example, F2.
8), the second ranging area groups 41 and 42
Cannot be measured by the second distance measuring sensor corresponding to Conversely, the imaging optical system 201 of the attached lens 200
Is smaller than or equal to the second open F value, the distance can be measured by the second distance measuring sensors corresponding to the second distance measuring area groups 41 and 42.

As is apparent from FIGS. 23 and 6, the second
The photoelectric conversion element arrays 246a to 246d constituting the second distance measurement sensors corresponding to the distance measurement area groups 41 and 42 of
Photoelectric conversion element arrays 146a to 146d constituting first distance measurement sensors corresponding to first distance measurement area groups 31 and 32
Rather than the optical axis L. That is, the second distance measuring sensor corresponding to the second distance measuring area groups 41 and 42 has a longer base line length than the first distance measuring sensor corresponding to the first distance measuring area groups 31 and 32. High ranging accuracy. Therefore, when the imaging optical system 201 having the open F value equal to or smaller than the second open F value is mounted, at least the subject or the portion of the subject located at the center of the screen has high ranging accuracy. The second distance measuring sensor can be used, and it is possible to focus on the subject with the distance measuring accuracy corresponding to the open F value of the imaging optical system of the lens to be used.

Next, the operation of the first embodiment will be described with reference to the flowchart shown in FIG. First,
When the lens 200 is mounted on the camera body 100 and the main switch is turned on (step S100), the AF CPU
Reference numeral 301 denotes an AF open F value stored in the lens CPU 204 (step S105), and the read A
It is determined whether or not the open F value for F is equal to or smaller than the second open F value (step S110). If the AF open F value is equal to or smaller than the second open F value (YES in step S110), the AF CPU 301
Are a first ranging sensor group (particularly, a photoelectric conversion element array) corresponding to the first ranging area groups 31 to 34, and a second ranging sensor group corresponding to the second ranging area groups 41 and 42. Is set to be used (step S115). On the other hand, AF
When the open F value for use is larger than the second open F value (NO in step S110), the AF CPU 301 uses only the first distance measurement sensor group corresponding to the first distance measurement area groups 31 to 34. Is set (step S120).

When any one of the first distance measuring sensor group, the second distance measuring sensor group, and only the first distance measuring sensor group is set, the AF CPU 301 performs distance measurement using these distance measuring sensor groups. Then, the defocus amount and the lens driving direction are calculated (step S125). Further, the AFCPU 30
1 controls the lens driving mechanism 203 using the calculated defocus amount and the driving direction of the lens, and
1 is moved (step S130).

When the movement of the imaging optical system 201 is completed, A
The FCPU 301 uses the imaging optical system 2
It is determined whether or not 01 is in focus (step S13)
5). If not in focus (N in step S135)
O), the AF CPU 301 calculates the defocus amount and the lens driving direction again (step S125), and moves the imaging optical system 201 (step S130). on the other hand,
If the camera is in focus (YES in step S135), the in-focus operation ends (step S140), and the process waits for the next operation, for example, turning on a shutter release button.

In the case of focus position detection using a plurality of ranging areas, a defocus amount is calculated for each ranging area, and the movement of the imaging optical system 201 is actually controlled from among the plurality of defocus areas. Is determined. As an example, the F value of the imaging optical system 201 is the second open F
If the value is smaller than the value (for example, F2.8), the arithmetic circuit 14
8 calculates a defocus amount for each ranging area by using ranging sensors corresponding to the first ranging area groups 31 to 34 and the second ranging area groups 41 and 42, respectively, The focus amounts are compared and, for example, data closest to the camera is output as the final defocus amount (near-position priority method). Similarly, when the F value of the imaging optical system 201 is larger than the second open F value, the arithmetic circuit 148 uses the distance measurement sensor groups corresponding to the first distance measurement area groups 31 to 34, respectively. The amount of defocus for each ranging area is calculated, and these defocus amounts are compared. For example, data closest to the camera is output as the final defocus amount.

As described above, according to the first embodiment, the second
When a lens having an open F value equal to or smaller than the open F value of the second lens is mounted, the distance between the base and the focus of the imaging optical system is increased using the second cross sensor having a long base line length and high distance measurement accuracy. The operation can be performed, and it is possible to obtain the ranging accuracy suitable for the open F value of the imaging optical system 201 of the mounted lens 200. In addition, since the first and second cross sensors are provided in the center of the screen, even if the contrast of the subject in the center of the screen or the part of the subject differs depending on the direction, for example, the direction in which the contrast is higher is higher. The focus position can be detected by using the distance measuring sensor, and the possibility that distance measurement cannot be performed is reduced.

(Second Embodiment) A focus position detecting apparatus according to a second embodiment of the present invention will be described with reference to FIGS. Note that the description of the parts common to the focus position detection device of the first embodiment will be omitted.

As is apparent from FIG. 9, in the second embodiment, the first distance measurement area groups 31 and 32 constituting the first cross sensor corresponding to the first open F-number are respectively located at the center of the screen. And the second ranging area groups 14 and b42 which are arranged so as to form approximately 45 degrees with respect to the vertical or horizontal direction of the screen and form a second cross sensor corresponding to the second open F-number.
Are arranged at the center of the screen and in parallel with each other in the vertical and horizontal directions of the screen.

The aperture mask 144 in the second embodiment
10 to 12 show the arrangement of the aperture, the re-imaging lens of the lens array 145, and the photoelectric conversion element array of the detection element 146, respectively. As is clear from FIG.
The second cross sensor constituted by the distance measurement area groups 41 and 42 has two photoelectric conversion element arrays 246 on the horizontal axis H passing through the center of the screen and symmetric with respect to the center of the screen.
a and 246b, and two photoelectric conversion element arrays 246c and 246 on the vertical axis V and symmetric with respect to the center of the screen.
d. On the other hand, the first cross sensor constituted by the first distance measurement area groups 31 and 32 is symmetrical with respect to a line that forms approximately 45 degrees with respect to the horizontal axis H or the vertical axis V and with respect to the screen center. Four photoelectric conversion element arrays 146a and 1
46b, 146c and 146d. Further, a distance measuring sensor group corresponding to the other first distance measuring area groups 32 and 34 also includes two photoelectric conversion element arrays 146e and 146f, 146g, and 146h provided symmetrically with respect to the horizontal axis H. .

The openings 144a to 144f, 24 of the aperture mask 144 correspond to the structure of the photoelectric conversion element array.
4a to 244d, re-imaging lens 1 of lens array 145
45a to 145h and 245a to 245d are also arranged symmetrically with respect to the center of the screen or the horizontal axis H. Other configurations and operations are the same as those of the first embodiment.
Thus, the same effects as in the first embodiment can be obtained also in the second embodiment.

(Third Embodiment) A third embodiment of the focus position detecting apparatus according to the present invention will be described with reference to FIGS. Note that the description of the parts common to the focus position detection device of the first embodiment will be omitted.

As is clear from FIG. 13, the third embodiment is different from the first embodiment in that it can focus on a subject or a portion of the subject located at a position further away from the center of the screen. Third distance measurement area groups 51 and 52 and corresponding distance measurement sensors are provided outside the first distance measurement area groups 33 and 34.

The aperture mask 144 according to the third embodiment.
14 to 16, the arrangement of the re-imaging lens of the lens array 145 and the arrangement of the photoelectric conversion element array of the detection element 146 are shown in FIGS. As is clear from the drawings, the third embodiment further includes third distance measurement area groups 51 and 5 in addition to the configuration of the first embodiment.
Openings 344a to 344 of aperture mask 144 corresponding to 2
d, recombination lenses 345a to 345d, and photoelectric conversion element arrays 346a to 346d.

The third distance measurement area groups 51 and 52 can be set in the following three ways. As a first case, the third ranging area groups 51 and 52 are
Pupil 30 of the imaging optical system having an open F-number (for example, F6.7)
(See FIG. 7). In this case, it is possible to perform the ranging or focusing operation using the third ranging area groups 51 and 52 for all the lenses 200 that can be mounted on the camera 100. However, the range over which the luminous flux passing through the pupil 30 of the imaging optical system having the first open F value can reach is narrow, and the third distance measurement area groups 51 and 52 can be set only at positions relatively close to the center of the screen. In addition, only the subject close to the center of the screen can perform the distance measurement or the focusing operation.

As a second case, the third ranging area group 5
The pupils 1 and 52 of the imaging optical system outside the range in which the light beam passing through the pupil 30 of the imaging optical system having the first open F value can reach and having the second open F value (for example, F2.8). It is provided in a range where the light beam passing through 50 can reach. In this case, the second
Imaging optical system 2 having an open F value larger than the open F value of
When the lens 200 having 01 is mounted, the distance measurement or focusing operation cannot be performed using the third distance measurement area groups 51 and 52. However, the range over which the luminous flux passing through the pupil 50 of the imaging optical system having the second open F value can reach is wide, and the third distance measurement area groups 51 and 52 can be set at positions relatively far from the center of the screen. The distance measurement or the focusing operation can be performed even on a subject away from the center of the screen.

As a third case, the third ranging area group 5
1 and 52 are set outside the range in which the light beam that has passed through the pupil 30 of the imaging optical system having the first open F-number can reach, and are intermediate between the first open F-number and the second open F-number. Pupil of the imaging optical system (pupils 30 and 50 in FIG.
Is provided in a range where the light beam that has passed through (the middle part) can reach.
In this case, the third ranging area group 5 is larger than the second case.
Although the range in which 1 and 52 can be set is narrowed, it is possible to increase the types of lenses 200 that can perform the distance measurement or the focusing operation using the third distance measurement area groups 51 and 52.

As described above, according to the third embodiment, in addition to the effects of the first embodiment, a distance measurement or focusing operation is performed on a subject or a part of the subject located further away from the center of the screen. Can be performed. Note that the features of the third embodiment may be added to the configuration of the second embodiment.

(Fourth Embodiment) A fourth embodiment of the focus position detecting apparatus according to the present invention will be described with reference to FIGS. Note that the description of the portions common to the focus position detection devices of the first to third embodiments will be omitted.

As is apparent from FIG. 17, the fourth embodiment has a structure similar to that of the first embodiment so that a subject or a portion of the subject located at a position further away from the center of the screen can be focused. Distance measurement area groups 35 and 36 belonging to the first distance measurement area group parallel to the horizontal axis H, are arranged outside the first distance measurement area groups 31 to 36 and on the circumference centered on the screen center. Third distance measuring area groups 51 to 54 and corresponding distance measuring sensors are provided.

The aperture mask 144 in the fourth embodiment
18 to 20, the arrangement of each re-imaging lens of the lens array 145 and the photoelectric conversion element array of the detection element 146 are shown in FIGS. As is clear from the drawings, the first embodiment further includes first ranging area groups 35 and 3 in addition to the configuration of the first embodiment.
Apertures 144i-k and 344a-344h of the aperture mask 144 corresponding to the sixth and third distance measurement area groups 51-54;
Recombination lenses 145i-145k and 345a-345
h, photoelectric conversion element arrays 146i to 146k and 346
a to 346h are provided.

As is clear from the figures, the first distance measurement area groups 35 and 36 include a central area among nine areas formed by dividing the screen into approximately three equal parts in the vertical and horizontal directions. And belongs to the first ranging area group. The third distance measurement area groups 51 to 54 are preferably set in the same manner as any of the first to third cases in the third embodiment. With such a configuration, the third
It is possible to perform the distance measurement or the focusing operation on a subject or a part of the subject in a wider range in the same manner as in the case of the first embodiment or more.

(Other Embodiments) In the above embodiments, F6.7 was used as the first open F value and F2.8 was used as the second open F value. However, the present invention is not limited to this. , Or another open F value. Further, although simply referred to as the open F value of the imaging optical system 201 of the lens 200, as described above, the open F value of the imaging optical system does not always match the open F value used in automatic focus adjustment. Accordingly, the first open F value and the second open F value of the imaging optical system 201 are respectively the actual open F value and A
It goes without saying that both the open F values for F are included. Further, in each of the above embodiments, the AF single-lens reflex camera has been described as an example of the device using the focus position detecting device. However, the present invention is not limited to this. Can be used.

[0055]

As described above, according to the focal position detecting device of the present invention, the focal position detecting device is provided within the first range where the light beam from the subject can reach by the first open F-number imaging optical system, A first ranging sensor group including a first cross sensor composed of two ranging sensors arranged to be orthogonal to each other, and an imaging optical system having a second open F value smaller than the first open F value Are provided in a second area to which a light beam from the subject can reach, and are arranged so as to be orthogonal to each other.
A second distance measuring sensor group including a second cross sensor composed of two distance measuring sensors, and a second open F value and a second open F value when the imaging optical system having a smaller open F value is mounted. 1
The focusing operation of the imaging optical system is performed using the distance measurement sensor group and the second distance measurement sensor group, and when the imaging optical system having an open F value larger than the second open F value is mounted, the first operation is performed. Since the focusing operation of the imaging optical system is performed using the distance measurement sensor group of
When an imaging optical system having a shallow depth of field with an aperture value close to the value is mounted, not only the first distance measurement sensor group but also a long base line provided at a position further away from the center of the screen. 2
The focusing optical system can be focused on the subject by using the distance measuring sensor group, and a focusing operation with high ranging accuracy can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an AF single-lens reflex camera in which each embodiment of a focus position detection device according to the present invention is used.

FIG. 2 is a perspective view showing a configuration of a first embodiment of a focus position detection device of the present invention.

FIG. 3 is a diagram showing an arrangement of distance measurement areas on a screen according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an aperture of an aperture mask according to the first embodiment.

FIG. 5 is a diagram illustrating an arrangement of a re-imaging lens according to the first embodiment.

FIG. 6 is a diagram illustrating an arrangement of a photoelectric conversion element array according to the first embodiment.

FIG. 7 is a diagram illustrating a state in which a light beam that has passed through a pupil of an imaging optical system reaches an imaging optical system array of a distance measurement sensor in the first embodiment.

FIG. 8 is a flowchart showing the operation of the first embodiment.

FIG. 9 is a diagram illustrating an arrangement of distance measurement areas on a screen according to a second embodiment of the present invention.

FIG. 10 is a diagram illustrating openings of an aperture mask according to a second embodiment.

FIG. 11 is a diagram illustrating an arrangement of a re-imaging lens according to a second embodiment.

FIG. 12 is a diagram illustrating an arrangement of a photoelectric conversion element array according to a second embodiment.

FIG. 13 is a diagram illustrating an arrangement of a distance measurement area on a screen according to a third embodiment of the present invention.

FIG. 14 is a diagram illustrating openings of an aperture mask according to a third embodiment.

FIG. 15 is a diagram illustrating an arrangement of a re-imaging lens according to a third embodiment.

FIG. 16 is a diagram illustrating an arrangement of a photoelectric conversion element array according to a third embodiment.

FIG. 17 is a diagram showing an arrangement of distance measurement areas on a screen according to a fourth embodiment of the present invention.

FIG. 18 is a diagram illustrating openings of an aperture mask according to a fourth embodiment.

FIG. 19 is a diagram illustrating an arrangement of a re-imaging lens according to a fourth embodiment.

FIG. 20 is a diagram illustrating an arrangement of a photoelectric conversion element array according to a fourth embodiment.

FIG. 21 is a diagram illustrating a configuration and a detection principle of a conventional focus position detection device.

FIG. 22 is a diagram illustrating a difference in incident light flux between two imaging optical systems having different F-numbers.

FIG. 23 is a diagram illustrating a relationship between a base line length of a distance measuring sensor and a distance measuring accuracy.

[Explanation of symbols]

 31 to 36: First ranging area group 41, 42: Second ranging area group 51 to 54: Third ranging area group 140: Focus position detecting device 141: Field mask 142: Condenser lens 143: Beam Splitter 144: aperture mask 144a to 144k: aperture 145: lens array 145a to 145k: re-imaging lens 146: detection element 146a to 146k: photoelectric conversion element array 244a to 244d: aperture 245a to 245d: re-imaging lens 246a to 246d : Photoelectric conversion element array 344a to 344h: Opening 345a to 345h: Re-imaging lens 346a to 346h: Photoelectric conversion element array

Claims (5)

[Claims] 1. A first distance measuring sensor which is provided in a first range within which a light beam from a subject can reach by an imaging optical system having a first open F-number and comprises two distance measuring sensors arranged orthogonal to each other. A first ranging sensor group including a cross sensor of
The two distance measuring sensors provided in the second area where the light flux from the subject can reach by the imaging optical system having the second open F value smaller than the open F value of A second distance measurement sensor group including a second cross sensor, and a second open F value and an open F value higher than the second open F value.
When the imaging optical system having a small value is mounted, the focusing operation of the imaging optical system is performed using the first distance measurement sensor group and the second distance measurement sensor group, and the aperture is larger than the second aperture F value. A focus position detecting device, wherein a focusing operation of an image pickup optical system is performed using a first distance measuring sensor group when an image pickup optical system having an F value is mounted. 2. The apparatus according to claim 1, wherein the first cross sensor and the second cross sensor are both arranged around the optical axis of the imaging optical system and are arranged at a certain angle to each other. 2. The focus position detecting device according to claim 1. 3. The focus according to claim 1, wherein the second distance measuring sensor group is provided at a position farther from the optical axis of the imaging optical system than the first distance measuring sensor group. Position detection device. 4. The first distance measuring sensor group and the second distance measuring sensor group each include a photoelectric conversion element array, and each photoelectric conversion element array is formed on the same chip. Item 4. The focus position detecting device according to any one of Items 1 to 3. 5. The first distance measuring sensor group and the second distance measuring sensor group further include a re-imaging lens group, and the four first re-imaging lens groups corresponding to the first cross sensor are: Four second re-imaging lens groups, which are radially integrated with each other about the optical axis of the imaging optical system and correspond to the second cross sensor group, have a first group around the optical axis of the imaging optical system. The focal position detecting device according to any one of claims 1 to 4, wherein the focal position detecting device is radially dispersed outside the re-imaging lens group.