JPH0727109B2 - Photoelectric adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an autofocus system of a secondary imaging shift system used for a single-lens reflex camera or the like, depending on the inclination of the sensor or the eccentricity of the secondary imaging lens. The present invention relates to a photoelectric adjustment device having an adjustment mechanism for eliminating a measurement error that occurs.

[Prior Art] In the focus detection device of the conventional secondary imaging deviation type, there is a problem that a distance measurement error occurs due to the inclination of the line sensor and the eccentricity of the secondary imaging lens. For example, if the line sensor is tilted even slightly, the focus detection surface is tilted, so that the distance measurement result naturally varies depending on where in the distance measurement field the subject is present. Also,
The same phenomenon occurs when the secondary imaging lens is decentered. Therefore, it is necessary to make an adjustment such that the light receiving surface of the line sensor, particularly the longitudinal direction thereof, is inclined with respect to the optical axis, and conventionally such an adjusting mechanism has been considered. However, in the related art, the adjustment of the inclination of the line sensor in the longitudinal direction causes a new inclination in a direction perpendicular to the adjustment, so that the adjustment is extremely difficult and a good distance measurement accuracy cannot be obtained. In particular, the conventional sensor has a problem that it is difficult to reliably chuck the sensor because the outer dimensions of the sensor package are not well tolerated and the lead wire is attached.

[Object of the Invention] An object of the present invention is to provide a highly accurate photoelectric adjustment device capable of removing a distance measurement error based on the inclination of the line sensor or the eccentricity of the secondary imaging lens in order to improve such a drawback of the conventional example. To do.

[Summary of the Invention] The gist of the present invention for achieving the above object is that a line sensor that receives a light beam and a sensor holding member that holds the light beam are in contact with each other at a contact surface inclined with respect to the optical axis. The line sensor is coupled to the fixed member via a fixed member and a rotary member, and the inclination of the line sensor is adjusted by rotating the rotary member with respect to the fixed member. It is a photoelectric adjustment device.

Embodiments of the Invention The present invention will be described in detail based on the illustrated embodiments.

FIG. 1 shows a basic configuration diagram of an optical system according to the present invention,
Reference numeral 1 denotes a photographing lens, which has a field mask 2, a field lens 3, a diaphragm 4 having two openings 4a and 4b symmetrical with respect to the optical axis, and a secondary element 5a and 5b. An imaging lens 5 and a line sensor 6 consisting of two elements 6a, 6b are arranged.

The field mask 2 in this block prevents unnecessary light beams outside the distance measuring field from entering the focusing device system, and the field lens 3 connects the openings 4a and 4b of the diaphragm 4 and the exit pupil S of the taking lens 1. By placing them in an image relationship, the light flux that has passed through the taking lens 1 is effectively guided to the line sensor 6. The diaphragm 4 is for limiting the light flux, and the two elements 5a and 5b of the secondary imaging lens 5 reconnect the light flux passing through different areas of the exit pupil S of the photographing lens 1 onto the line sensor 6. It plays the role of making the image. Two elements of line sensor 6
From the outputs of 6a and 6b, the correlation between the positions of the two images re-imaged by the secondary imaging lens 5 is obtained, and the defocus amount is detected. The secondary imaging lens 5 is an exit pupil S of the taking lens 1.
A secondary image having a parallax is formed on the array of photoelectric elements of the line sensor 6 from the light fluxes passing through different areas.

If the two elements 6a and 6b of the line sensor 6 are tilted around the Y'axis as indicated by the dotted line, the distance measurement result depends on the position of the subject in the distance measurement field as described above. Will be different. That is, as shown in FIG. 2, a distance measurement error occurs depending on whether the subject is placed at the left end b1 or the right end b2 in the distance measuring field B, but in the present invention, this distance measurement error can be almost eliminated. It is possible.

FIG. 3 is a cross-sectional view when the focus detection system according to the present invention is applied to a single-lens reflex camera, in which a quick return mirror 7 is arranged behind the taking lens 1, and the light flux reflected upward here is a condenser. It is guided to a finder system including a lens 8, a penta roof prism 9, and an eyepiece lens 10. A photosensitive film 11 is arranged behind the quick return mirror 7 and constitutes a photographing system together with the photographing lens 1. A sub-mirror 12 is attached to the back of the light transmitting portion of the quick return mirror 7 so that the sub mirror 12 is flipped up or returned together with the quick return mirror 7. On the reflection side of the sub-mirror 12, the focusing optical system of FIG.
As shown in the sectional view of the drawing, the field mask 2, the field lens 3, and the field mask 3 arranged near the planned image forming surface of the taking lens 1.
A mirror 13 for bending the optical path, a diaphragm 4 having two openings 4a and 4b symmetrical with respect to the optical axis, a secondary imaging lens 5 and a line sensor 6 are sequentially arranged.

FIG. 5 is an exploded view showing a specific structural example of the focusing unit. All the optical members from the field mask 2 to the line sensor 6 shown in FIGS.
They are attached together in one unit body 14.
An infrared cut filter 15 and an antireflection member 16 are inserted between the sub mirror 12 and the field mask 2, and the antireflection member 16 prevents reflected light on the surface of the infrared cut filter 15 from reaching the film 11. It is for doing.
Between the line sensor 6 and the unit main body 14 that holds the line sensor 6, as will be described in detail later, an adjusting member composed of a fixed member and a rotating member that come into contact with each other at a contact surface inclined with respect to the optical axis, namely, a fixed stage 17 The rotary stage 18 is interposed, and the tilt of the line sensor 6 can be adjusted by rotating the rotary stage 18. In the illustrated case, the fixed stage 17 located near the line sensor 6 is connected to the line sensor 6, but the fixed stage 17 may be formed integrally with the package of the line sensor 6. The unit main body 14 is fixed to the front plate of the camera by the mounting screws 19, the line sensor 6 is temporarily held on the fixed stage 17 by the sensor holding pin 20, and the field lens 3 is fixed to the unit main body 14 by the field lens adjusting pin 21. It is designed to be adjustable.

Next, the assembling procedure of this focusing unit will be described with reference to the arrow A in FIG.
It will be described according to the procedure of 1, A2, A3 ....

A1: The infrared cut filter 15 is attached to the antireflection member 16.

A2: Attach the field mask 2 to the infrared cut filter 15.

A3: Place the field lens 3 on the unit body 14.

A4: The hole 16a of the antireflection member 16 is made into the dowel 14a of the unit main body 14.
The cut filter 15 is assembled into the unit main body 14 by press fitting into.

A5: Attach the mirror 13 to the unit body 14.

A6: The diaphragm 4 is attached to the secondary imaging lens 5.

A7: The positioning portion 5c of the secondary imaging lens 5 is attached to the unit body 14
The secondary imaging lens 5 is assembled into the unit main body 14 while being positioned in the rotational direction.

A8: The fixed stage 17 is attached to the line sensor 6.

A9: The rotary stage 18 can be slammed into the unit body 14.

A10: The fixed stage 17 sandwiches the rotary stage 18,
The fixed stage 17 is incorporated in the unit body 14, and the protrusion 17a of the fixed stage 17 is temporarily held by the engaging portion 14b of the unit body 14.

Next, the adjustment procedure will be described according to the arrows S1 to S9 in the drawing (however, S3 is not shown). First, the unit body 14 is attached to the adjustment tool, and adjustment is performed by the following procedure.

S1: The sensor holding pin 20 is inserted into the hole 6c and the cutout hole 6d of the line sensor 6 to insert the line sensor 6 into the unit main body 14.
Regulate the position of.

S2: The pupil is projected, that is, the focusing unit is aligned with the optical axis of the front plate of the camera body. The apertures 4a and 4b of the diaphragm 4 are adjusted by the field lens 3 so that they are correctly projected into the exit pupil S of the taking lens 1. Actually, the field lens adjusting pin 21 is provided in the hole 3a of the field lens 3 and the cutout hole.
After being inserted into 3b, the field lens 3 is decentered in parallel and fixed with an adhesive. In this case, the adjustment standard uses the tool mirror box and the tool exit pupil.

S3: Although not shown, the shading correction is performed by using the uniform luminance surface chart, and the uneven light amount on the line sensor 6 and the uneven sensitivity of the line sensor 6 are collectively corrected by the EEPROM.

S4: The rotary stage 18 is chucked and rotated about the X ′ axis, and the line sensor 6 and the fixed stage 17 are integrally swung about the Y ′ axis to adjust the inclination of the line sensor 6. The adjustment method and principle will be described later with reference to FIG. After this adjustment, the fixed stage 17 and the rotary stage 18 are bonded and fixed.

S5: Pull out the sensor holding pin 20.

S6: While keeping the chucking of the rotary stage 18, the rotary stage 18 is translated in the Y′-Z ′ plane, and the line sensor 6 is positioned by aligning the optical axis with the center of the line sensor 6. The claw (not shown) chucking the rotary stage 18 can be moved not only in the rotation but also in the Y'and Z'directions.

S7: The rotary stage 18 is rotated to adjust the rotation of the line sensor 6 around the X'axis, and the line sensor 6 is adjusted in the Z'axis direction to adjust the glare.

Since the adjustment as the focusing unit is completed by the above steps S1 to S7, the focusing unit is removed from the adjustment tool, and the following S8 and S9 are adjusted.

S8: When the focusing unit is attached to the front plate of the camera, the entire focusing unit is moved in the Y-axis direction to adjust the parallax so that the distance measuring center coincides with the distance measuring frame center in the viewfinder. In this case, the mounting portion on the bottom surface of the front plate of the camera is provided with a groove for fitting with the mounting seat 14e of the unit main body 14, and the focusing unit is moved in parallel with this as a guide.

S9: After fixing the unit main body 14 to the front plate of the camera with the mounting screw 19, the focus of the focusing unit is electrically matched using the EEPROM.

The inclination adjustment of the line sensor 6 in the above-mentioned step S4 and its principle will be described in detail below. In FIG. 5, the rotary stage 18
The concave surface 18a around the chuck is chucked by the three claws of a jig (not shown), and the rotary stage 18 is rotated about the X'axis. In this case, the contact surfaces 17b, 18b of the fixed stage 17 and the rotary stage 18
Are parallel to each other and are inclined at a predetermined angle with respect to the optical axis. Further, since the rotation of the fixed stage 17 and the line sensor 6 is restricted by the sensor holding pin 20, by rotating only the rotary stage 18, the fixed stage 17 and the line sensor 6 are integrated to rotate around the Y ′ axis. Rotation is adjusted.

The principle is shown in FIG. 6 (a). Since the contact surfaces 17b, 18b of the fixed stage 17 and the rotary stage 18 are inclined with respect to the optical axis as described above, the normal N1 of the contact surface 18b Suppose the tilt angle is φ. At the initial position of the fixed stage 17, the normal line N1 is in the X'-Y 'plane. Here, when only the rotary stage 18 is rotated counterclockwise by the angle θ, the rotary stage 18 begins to tilt with respect to the optical axis as shown in FIG. It is represented by an inclination angle θy ′ from the optical axis of the normal line N2 at. Since the fixed stage 17 is shown so as to swing around the point C where the optical axis intersects the contact surfaces 17b and 18b,
Although 17c is shifted by dz in the Z'axis direction, the fixed stage 17 and the line sensor 6 are actually the sensor holding pin 20.
The shift amount dz is generated by the contact surface.
The center of the line sensor 6 is not displaced from the optical axis because it is canceled by the sliding in the Z'axis direction between 17b and 18b.

The relationship between the angles θ and θy ′ described above is expressed as shown in FIG. It should be noted here that the normal line N1 has a tilt angle θz ′ around the Z ′ axis in addition to the tilt angle θy ′ around the Y ′ axis, but the actual adjustment range is −θ _{1 to} θ ₁ Since it is a very narrow range, the tilt angle θz ′ is almost negligible compared to the tilt angle θy ′, and there is no practical problem.

In the conventional case, only the rotary stage 18 is provided, the fixed stage 17 is not provided, and the line sensor 6 is in direct contact with the contact surface 18b of the rotary stage 18. Therefore, θz ′ =
There is an inclination of φ, which is shown in FIG. 7 (b). Here, in order to reduce the tilt angle θz ′, φ
Can be made smaller, but then the same tilt angle θy ′
In order to obtain the angle, it is necessary to increase the angle θ, and it becomes difficult to adjust due to the restriction of the rotation range of the jig.

When a mirror is interposed between the secondary imaging lens 5 and the line sensor 6 as in the conventional example, the tilt of the mirror is set so as to cancel the tilt angle θz ′. Although the angle θz ′ can be made substantially zero, the contact surface 1 of the fixed stage 17 facing the contact surface 18b of the rotary stage 18 is eventually used in the method without the mirror as in this embodiment.
There is only a way to tilt 7b.

In contrast to the above-mentioned embodiment, the line sensor 6 is deformed so as to elastically hold it in the unit main body 14 that is its holding member
The fixed stage 17 may be rotated, or the fixed stage 17 may be abolished and the package surface of the line sensor 6 may be an inclined surface parallel to the contact surface 18b so that the line sensor 6 and the rotary stage 18 come into contact immediately after. You may make it a system. Further, even if one of such contact surfaces 18b, 17b has a discontinuous structure, there is no problem. Further, the other surface of the rotary stage 18 may be tilted, another fixed stage having an inclined surface facing the tilted surface may be added, and the rotary stage 18 may be sandwiched between two fixed stages.

[Advantages of the Invention] As described above, when the adjustment of the line sensor in the longitudinal direction is performed, the photoelectric adjustment device according to the present invention causes almost no inclination in the direction orthogonal to the adjustment, and thus the adjustment is easy and easy to measure. Distance accuracy can be improved. Further, by appropriately selecting the angle of the contact surface between the rotary stage and the fixed stage, the tilt angle θy ′ with respect to the adjustment angle θ can be sensitively and arbitrarily adjusted. Further, instead of chucking and rotating the line sensor itself, chucking the rotating stage and rotating integrally with the line sensor allows all tilt, positioning, rotation, etc. of the line sensor to be performed without re-chucking. There is also an advantage that can be adjusted.

[Brief description of drawings]

The drawings show an embodiment of a photoelectric adjustment device according to the present invention. Fig. 1 is a basic configuration diagram, Fig. 2 is an explanatory diagram of distance measurement error, Fig. 3 is a sectional view in a camera, and FIG. 4 is a cross-sectional view of a part of the same seen from another direction, FIG. 5 is an exploded view of a specific groove of the focusing unit, FIG. 6 is a principle view of sensor tilt adjustment, and FIG. It is the graph figure which represented typically. Reference numeral 1 is a projection lens, 2 is a field mask, 3 is a field lens, 4 is a diaphragm, 5 is a secondary imaging lens, 6 is a line sensor, 7 is a quick return mirror, 12 is a sub-mirror,
13 is a mirror, 14 is a unit body, 15 is an infrared cut filter, 16 is an antireflection member, 17 is a fixed stage, and 18 is a rotary stage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Akashi, Akira Akashi, 770 Shimonoge, Takatsu-ku, Kawasaki, Kanagawa Canon Inc., Tamagawa Business Office (72) Keishi Otaka, 770, Shimonoge, Takatsu-ku, Kawasaki, Kanagawa Canon Inc. Company Tamagawa Plant (72) Inventor Takeshi Koyama, Tamano Plant, 770, Shimonoge, Takatsu-ku, Kawasaki City, Kanagawa Canon Inc. (56) Reference JP-A-60-263915 (JP, A)

Claims (2)

[Claims] 1. A fixed member and a rotating member, which come into contact with each other at a contact surface inclined with respect to an optical axis, are interposed between a line sensor that receives a light beam and a sensor holding member that holds the line sensor. A photoelectric adjusting device, characterized in that the inclination of the line sensor is adjusted by being connected to a fixed member and rotating the rotating member with respect to the fixed member. 2. The photoelectric adjustment device according to claim 1, wherein the fixed member and the rotary member are annular.