JP2001133681A - Multi-point focus detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focus detector which is easily assembled and adjusted and has plural focus detection areas. SOLUTION: Object luminous fluxes transmitted through plural focus detection apertures 12A, 12B, and 12C, which are provided in a prescribed arrangement pattern on a film equivalent surface are received by corresponding CCD line sensors 27A, 27B, and 27C, which are arranged in an arrangement pattern different from that of focus detection apertures. In this multiple AF(automatic focusing) sensor unit 11, mirrors 15A, 15B, 15C, 17B, and 17C which reflect object luminous fluxes LA, LB, and LC transmitted through the focus detection apertures 12A, 12B, and 12C in prescribed directions to make CCD line sensors 27A, 27B, and 27C receive them are formed integrally into an identical mirror unit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multipoint focus detection device suitable for optical equipment such as a single-lens reflex camera and capable of detecting a focus in a plurality of focus detection areas.

[0002]

2. Description of the Related Art In recent years, a single-lens reflex camera equipped with a multi-focus detection unit capable of detecting a focus in a plurality of focus detection areas has been developed. The optical system of the conventional multi-focus detection unit is configured such that each subject light flux passing through a plurality of on-axis and off-axis focus detection areas is bent by a mirror and is incident on a horizontally arranged light receiving element. It is. For example, the object light flux passing through the focus detection area on the horizontally long axis arranged on the axis is set to 1
The light is deflected once by a single mirror and is connected to a corresponding light receiving element array disposed horizontally. At this time, an image observed through the focus detection area on the horizontal long axis is pupil-divided and re-imaged on the corresponding light receiving element row. In addition, the light beam that has passed through the vertically long peripheral focus detection area arranged off-axis is deflected twice by two mirrors, and is incident on the corresponding light receiving element array arranged horizontally. When making it enter like this,
An image observed through the vertically-long off-axis focus detection area is pupil-divided and re-imaged on a corresponding light receiving element array.

FIG. 5 shows an exploded configuration of the conventional multipoint focus detection unit. In this multi-point focus detection unit, main components and sensors of a focus detection optical system are housed in a sensor case and sealed by an AF sensor cover, but only the AF sensor cover 131 is illustrated. A field mask 112 that regulates a focus detection area is arranged near a film equivalent plane of the camera (not shown) (planned focal plane of the photographing lens). As for the focus detection area, for example, the center focus detection area is regulated by the horizontally long focus detection aperture 112a, and the focus detection areas located on the left and right are regulated by the vertically long focus detection apertures 112b and 112c.
The luminous flux transmitted through each of the focus detection apertures 112a to 112c is converted into a condenser lens 113a, 113b, 113c.
And is deflected in a direction of entering the sensor unit through the corresponding opening 131a, 131b, 131b of the AF sensor cover 131.

[0006] The central subject light flux transmitted through the central focus detection opening 112a, condenser lens 113a and opening 131a is bent in the optical path toward the sensor unit 127 (upper right in FIG. 5) by a mirror 117a. On the other hand, the left and right subject light beams transmitted through the condenser lens 113b, the opening 131b, the condenser lens 113c, and the opening 131c are first left and right first mirrors 115, respectively.
b, 115c, the light is deflected in a direction approaching the central subject light flux, and further left and right second mirrors 117b, 117
By c, it is bent in the direction of the sensor unit 127 (upper right direction in FIG. 5).

The mirrors 117a, 117b, 11
The center, left, and right subject luminous fluxes reflected by 7 c pass through the infrared filter 119 and are transmitted to the corresponding condenser lens 12.
1a, 121b, 121c, the separator masks 123a, 123b, 123c as pupil dividing means, the separator lenses 125a, 125b, 125c, and the corresponding line sensors 127a, 1b of the sensor unit 127.
Object images (light amount distribution) are formed on 27b and 127c.

Here, left and right first peripheral mirrors 115 are provided.
b and 115c are integrally formed on the same first mirror unit 115, and the central mirror 117a and the left and right second
The peripheral mirrors 117b and 117c are formed integrally with a second mirror unit 117 different from the first mirror unit 115. Therefore, at the time of assembling, first, the relative positions of the first and second mirror units 115 and 117 are adjusted and fixed with an adhesive, and the first and second mirror units 115 and 117 are further fixed.
The second mirror units 115 and 117 are mounted on the AF sensor cover 131 or a sensor case (not shown) on which the AF sensor cover 131 is mounted.

However, this type of multi-point focus detecting device can usually cause errors such as a manufacturing error and an assembly error of each member. Therefore, when assembling, the positions of the first mirror unit 115 and the second mirror unit 117 can be reduced. Adjustment, first and second mirror units 115 and 117 and AF sensor cover 131
Position adjustment has to be performed, and the adjustment is troublesome.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a focus detecting device having a plurality of focus detecting areas, which is easy to assemble and adjust, in view of the problems of the prior art.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method of disposing each light beam transmitted through a plurality of focus detection areas provided in a predetermined arrangement pattern on a film equivalent surface in an arrangement pattern different from the predetermined arrangement. A focus detection device for receiving light from a corresponding light receiving element array arranged in the light receiving element array, wherein each subject light flux transmitted through each of the focus detection areas is reflected once or plural times in a predetermined direction to the light receiving element array. It is characterized in that a plurality of reflecting surfaces to be incident are provided, and the plurality of reflecting surfaces are integrally formed on the same member. According to this configuration, since the reflecting surfaces are integrally formed on the same member, there is no need to adjust the reflecting surfaces when assembling the reflecting surfaces, and the adjustment work is facilitated.

[0010] In one embodiment of the present invention, the focus detection area includes a central focus detection area provided horizontally at the center of the photographing screen, and a vertical left side provided at the left and right of the center focus detection area. A light receiving element array having a right focus detection area and receiving a subject light flux passing through each of the focus detection areas is arranged on the same straight line. In this case, each reflecting surface
A mirror that reflects the central subject light flux transmitted through the central focus detection area toward the corresponding light receiving element row,
The left, the left reflecting the right subject light flux transmitted through the right focus detection area in the direction approaching the central subject light flux,
A right first mirror, and left and right second mirrors for reflecting the left and right subject light beams reflected by the left and right first mirrors toward the corresponding light receiving element rows, respectively. Are integrally formed on the same mirror unit.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. First, an overview of a single-lens reflex camera as an embodiment to which the multipoint focus detection device of the present invention is applied is shown in FIG.
This will be described with reference to FIG. The AF single-lens reflex camera includes a camera body 71 and an A
An F-capturing lens 51 is provided. The camera body 71 includes a so-called multi-point focus detection unit (multi-point auto focus unit) and an automatic focus adjustment unit that moves the focus adjustment lens group of the photographing lens 51 to a focus position based on the detection result of the focus detection unit. Have.

The subject light beam entering the camera body 71 from the photographing lens 51 is reflected by the main mirror 73 toward the pentaprism 77 constituting the finder optical system, and is reflected a plurality of times in the pentaprism 77 to remove the eyepiece. Inject through. On the other hand, a part of the subject light beam incident on the half mirror portion 74 of the main mirror 73 is transmitted therethrough and reflected downward by the sub-mirror 75, so that a multi-AF sensor unit (multi-point focus detection device) as multi-point focus detection means ) 11. The multi AF sensor unit 11 is, for example, a so-called phase difference type distance measuring sensor, and in the present embodiment, has three focus detection areas 13.
A sensor unit 27 having three line sensors 27a, 27b, 27c as light receiving element rows corresponding to a, 13b, 13c is provided (see FIG. 1). Each line sensor 2
7a, 27b and 27c are located on the same plane and on the same straight line.

The output (integrated data) of the multi-AF sensor unit 11 is input to the main CPU 81. The main CPU 81 calculates a defocus amount by a predetermined calculation based on integral data for each line sensor input from the multi-AF sensor unit 11. Then, based on the defocus amounts, the defocus amount and priority of the line sensor to be used are set, and the AF motor 83
And the number of rotations (number of pulses output by the encoder 85) are calculated. Then, the main CPU 81 drives the AF motor 83 via the AF motor drive circuit 82 based on the rotation direction and the number of pulses. In this drive, the main CPU 81 counts the pulses output from the encoder 85 in conjunction with the rotation of the AF motor 83, and when the count value reaches the number of pulses, the AF motor 8
Stop 3

The rotation of the AF motor 83 is controlled by the gear block 8.
4. The light is transmitted to the photographic lens 51 through a connection between a joint 87 provided on the mount of the camera body 71 and a joint 57 provided on the mount of the photographic lens 51. In the photographing lens 51, the focus adjustment lens 53 moves forward and backward via the lens driving mechanism 55 by the rotation transmitted to the joint 57.

The CPU 81 calculates an appropriate shutter speed and an aperture value based on photometric data and the like input from the photometric IC 78 via a peripheral control circuit 79, and outputs a shutter device and an aperture device (not shown) via the peripheral control circuit 79. Is driven to perform exposure, and when the exposure is completed, processing relating to photographing, such as winding up a film and mechanically charging a shutter device, is performed. EEPR as external memory means
The OM 86 stores, in addition to various constants specific to the camera body 71, predetermined values required for the integral control of the present invention.

Further, the camera is provided with a photometric switch SWS which is turned on when a release button (not shown) is half-pressed and a release switch SWR which is turned on when the release button (not shown) is fully pressed. The on / off information of these switches SWS and SWR is input to the main CPU 81, and the CPU 81 executes a process according to the state of the switch that has been turned on.

On the other hand, the taking lens 51 is provided with a lens driving mechanism 55 for moving a focusing lens 53 as a focusing optical system along the optical axis, and a mount portion of the taking lens 51. A lens-side joint 87 is connected to the joint 87 and transmits the rotation of the AF motor 82 to the lens driving mechanism 55. In addition,
Although not shown, the photographing lens 51 includes a ROM in which photographing lens specific information is stored, a CPU for calculating lens variable information by calculation, and the like, and exchanges these data and commands with the peripheral control circuit 79.

The configuration of the multi-AF sensor unit 11 according to the embodiment of the present invention will be described in more detail with reference to FIG. FIG. 1 is an exploded perspective view showing main optical elements of a multi-AF sensor unit 11 to which the present invention is applied. In the multi-AF sensor unit 11, three focus detection areas provided in an H-shaped arrangement pattern are arranged on a film equivalent surface, and each subject light flux transmitted through each focus detection area is subjected to focus detection. This is a configuration in which a line sensor as a corresponding light receiving element row arranged on a linear pattern, which is different from the area pattern, receives light.

The film equivalent surface of the camera (photographing lens 51)
A field mask 12 having a central field aperture 12A for regulating the central focus detection area and left and right field apertures 12B and 12C for describing the left and right focus detection areas is arranged on or near the front and rear of the predetermined focal plane. Have been. The luminous fluxes LA, L of the subject passing through the respective field openings 12A, 12B, 12C.
B and LC are condenser lenses 13A, 13B and 1 formed integrally with the condenser lens plate 13, respectively.
It is incident on 3C and is transmitted.

The central subject light beam LA transmitted through the condenser lens 13A is reflected toward the light receiving element row by the central mirror 15A. On the other hand, the left and right viewing apertures 13
First, the left and right subject light beams LB and LC transmitted through B and 13C are first reflected by the left and right first mirrors 15B and 15C in a direction approaching the central light beam LA, and further left and right second light beams. The light is reflected toward the light receiving element rows by the mirrors 17B and 17C.

Each of the subject light beams LA, LB, and LC reflected by the mirrors 15A, 17B, and 17C is transmitted to an infrared filter 19.
And the corresponding condenser lenses 21A, 21B,
21C, the separator masks 23A, 23B, and 23C as pupil dividing means, and the separator lenses 25A and 25A,
5B, 25C, the corresponding line sensor 27A,
A pair of subject images (light quantity distribution) are formed on 27B and 27C. Each light receiving element of each of the line sensors 27A, 27B, and 27C photoelectrically converts the received subject image into an electric signal corresponding to the luminance and outputs an image signal. The condenser lenses 21A, 21B, 21C are formed on one lens plate 21, and the separator masks 23A, 23B,
23C is formed on one separator mask plate 23, and the separator lenses 25A, 25B, 25C are formed integrally with one lens plate 25.

In this embodiment, the center mirror 15A, the left and right first mirrors 15B and 15C, and the left and right second mirrors 17B and 17C are integrated into the same mirror unit 18. It is characterized by being formed. The mirror unit 18 is, for example, injection-molded with a synthetic resin. At this time, the mirror unit 18 is also integrally formed with a flat surface serving as a reference surface of each of the mirrors 15A, 15B, 15C, 17B, 17C. A mirror surface is formed on this flat surface by aluminum evaporation or the like, and this mirror surface constitutes mirrors 15A, 15B, 15C, 17B, and 17C.

The above-described members constituting the multi-AF sensor unit 11 are an AF sensor unit case composed of an AF sensor cover 31 and an AF sensor case 33 as shown in a perspective view in FIG. Attached to. The condenser lens plate 13 and the field mask 12 are arranged on the surface of the AF sensor cover 31 in this order from the cover side.
Is attached. The AF sensor cover 31 allows the subject light beams LA, LB, and LC transmitted through the field openings 12A, 12B, and 12C of the field mask 12 and the corresponding condenser lenses 13A, 13B, and 13C to enter the AF sensor case 33. Openings 31A, 31B, and 31C are formed. Inside the AF sensor case 33, a mirror unit 18, an infrared filter 19, a lens plate 2
1. Separator mask plate 23, lens plate 2
5 and the sensor unit 27 are mounted.

The mirror unit 18 is fixed at a predetermined position in the AF sensor case 33. The positioning adjustment work at the time of fixing includes mirrors 15A, 15B, 15C, 1
Since 7B and 17C are already integrated, only one operation of adjusting the position and direction of the mirror unit 18 is required, which is easy.

Although the illustrated embodiment has three focus detection areas, the present invention can be applied to a multi-focus detection apparatus having four or five or more focus detection areas.

[0026]

As is clear from the above description, the present invention
Since a plurality of mirrors for deflecting the subject light flux transmitted through the plurality of focus detection areas in the direction toward the corresponding light receiving element row are formed integrally, positioning of these mirrors is facilitated, and adjustment and assembly work at the time of assembly are performed. Becomes easier.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an essential part of an embodiment of a multipoint focus detection apparatus according to the present invention.

FIG. 2 is a perspective view showing an appearance of a housing of the multipoint focus detection device.

FIG. 3 is a sectional view taken along section line III-III in FIG. 2;

FIG. 4 is a block diagram illustrating an outline of an embodiment of a single-lens reflex camera equipped with the multipoint focus detection device.

FIG. 5 is an exploded perspective view showing a main part of a conventional multipoint focus detection device.

[Explanation of symbols]

Reference Signs List 11 Multi AF sensor unit (multipoint focus detection device) 12 Field mask 13 Condenser lens plate 15A Central mirror 15B Left first mirror 15C Right first mirror 17B Left second mirror 17C Right second mirror 18 Mirror unit 27 Sensor unit 27A 27B 27C CCD line sensor (light receiving element array) 51 Photographing lens 71 Camera body

Claims (4)

[Claims] 1. A corresponding light receiving element arranged in a different arrangement pattern from each of the subject light beams transmitted through a plurality of focus detection areas provided in a predetermined arrangement pattern on a film equivalent surface. A focus detection device for receiving light in a row, comprising a plurality of reflection surfaces for reflecting each subject light flux transmitted through each of the focus detection areas once or a plurality of times in a predetermined direction and entering the light receiving element row. The plurality of reflecting surfaces are integrally formed on the same member,
A multi-point focus detection device characterized by the above-mentioned. 2. The multi-point focus detection device according to claim 1, wherein the focus detection area is provided at a central portion of a photographing screen in a horizontally long state, and at right and left sides of the center focus detection area. A multi-point focus detection device having a vertically elongated left and right focus detection areas, and a light receiving element array for receiving a subject light beam passing through each of the focus detection areas is arranged on the same straight line. 3. The multi-point focus detection device according to claim 2, wherein the reflection surface reflects a central subject light flux transmitted through the central focus detection area toward the corresponding light receiving element row, The left and right subject light beams that have passed through the left and right focus detection areas are reflected by the left and right first mirrors that reflect in the direction approaching the central subject light beam, and the left and right first mirrors. A multi-point focus detection device comprising left and right second mirrors for reflecting left and right subject light beams toward the corresponding light receiving element rows, and these mirrors are integrally formed in the same mirror unit. 4. The multi-point focus detecting device according to claim 1, wherein the plurality of reflecting surfaces are formed by aluminum evaporation on a flat surface of a mirror unit formed by injection-molding a synthetic resin. Multi-point focus detection device.