JPS62161110A - Photoelectric adjuster - Google Patents

Abstract

PURPOSE:To eliminate the error of distance measurement arising from the inclination of a line sensor for photodetection of a luminous flux and the eccentricity of a secondary imaging lens by interposing adjusting members which contact each other at the contact surfaces inclined with the optical axis between the line sensor and sensor holding member for holding the sensor. CONSTITUTION:All the optical members from a sub-mirror 12 up to the line sensor 6 are concentrically mounted to one unit body 14. An IR cut filter 15 and a reflection preventive member 16 are inserted between the mirror 12 and a field mask 2. The member 16 is used to prevent the arrival of the reflected light from the surface of the filter 15 at a film 11. The adjusting members consisting of a stationary member and rotating member which contact each other at the contact surfaces inclined with the optical axis, i.e., a stationary stage 17 and a rotating stage 18 are interposed between the line sensor 6 and the unit body 14 holding the same. The inclination of the line sensor 6 is adjusted by rotating the stage 18.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to - In an autofocus system using a secondary imaging shift method used in an eye reflex camera, etc., the tilt of the sensor and the eccentricity of the secondary imaging lens This invention relates to a photoelectric adjustment device equipped with an adjustment mechanism to eliminate measurement errors caused by

[Prior Art] Conventional secondary imaging shift type focus detection devices have the problem of causing distance measurement errors due to the inclination of the line sensor and the eccentricity of the secondary imaging lens. For example, even if the line sensor is slightly If it is tilted, it means that the focus detection surface is tilted.

The distance measurement result naturally depends on where the subject is located in the distance measurement field of view. Furthermore, a similar phenomenon occurs when the secondary imaging lens is decentered. Therefore, it is necessary to make adjustments such as tilting the light receiving surface of the line sensor, especially its longitudinal direction, with respect to the optical axis, and such adjustment mechanisms have been considered in the past. However, with conventional sensors, adjusting the longitudinal direction of the line sensor creates a new inclination in the direction perpendicular to it, making adjustment extremely difficult and making it difficult to obtain good ranging accuracy. Since the external dimension tolerance of the package is not good and lead wires are attached, there is a problem that it is difficult to reliably chuck the sensor.

[Object of the Invention] In order to improve the drawbacks of the conventional example, the object of the present invention is to provide a highly accurate photoelectric adjustment device that can eliminate distance measurement errors caused by the inclination of the line sensor and the eccentricity of the secondary imaging lens. It is about providing.

[Summary of the invention] The gist of the present invention is to achieve the above objects.

An adjustment member that contacts each other with a contact surface inclined with respect to the optical axis is interposed between a line sensor that receives a light beam and a sensor holding member that holds it, and the adjustment member is adjusted relative to the holding member. The photoelectric adjustment device is characterized in that the inclination of the line sensor is adjusted by rotating it.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows a basic configuration diagram of an optical system according to the present invention,
Reference numeral 1 designates a photographing lens, which sequentially includes a field mask 2, a field lens 3, a diaphragm 4 having two apertures 4a and 4b symmetrical to the optical axis along its tip axis, and a secondary lens consisting of two elements 5a and 5b. An imaging lens 5. A line sensor 6 consisting of two elements 6a, 6b is arranged.

The field mask 2 therein prevents unnecessary light beams outside the distance measurement field from entering the focusing system, and the field lens 3 connects the apertures 4a and 4b of the diaphragm 4 with the exit pupil S of the photographing lens 1. By placing it in an image relationship, it plays the role of effectively guiding the light flux that has passed through the photographing lens 1 to the line sensor 6.

The aperture 4 is for restricting the light flux, and the two elements 5a and 5b of the secondary imaging lens 5 refocus the light flux passing through different areas of the exit pupil S of the photographing lens 1 onto the line sensor 6. It has the role of creating images. Line sensor 6-2
From the outputs of the two elements 6a and 6b, the correlation between the positions of the two images re-formed by the secondary imaging lens 5 is determined, and the amount of defocus is detected. The secondary imaging lens 5 forms a secondary image with parallax from the light beams passing through different regions of the exit pupil S of the photographic lens 1 on the array of photoelectric elements of the line sensor 6.

Note that the two elements 6a and 6b of this line sensor 6 are Y
If it is tilted around the ° axis as shown by the dotted line, the distance measurement results will vary depending on where the subject is in the distance measurement field of view, as described above. In other words, as shown in FIG.
However, in the present invention, it is possible to almost eliminate this distance measurement error.

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. Lens 8. It is guided to a finder system consisting of a penta roof prism 9 and an eyepiece lens 10. Further, a photosensitive film 11 is arranged behind the quick return mirror 7.

Together with the photographic lens 1, it constitutes a photographing system. Note that there is a sub-mirror 1 behind the light-transmitting part of the quick return mirror 7.
2 is attached so that it can be flipped up or returned together with the quick return mirror 7. On the reflection side of this sub-mirror 12, there is a photographing lens 1, as shown in the sectional view of FIG. 4, which is a view of the focusing optical system of FIG.
A field mask 2, a field lens 3, a mirror 13 for bending the optical path, an aperture 4 having two apertures 4a and 4b symmetrical to the optical axis, and a secondary image forming A lens 5 and a line sensor 6 are arranged in sequence.

FIG. 5 is an exploded view showing a specific example of the configuration of the focusing unit. All the optical members from the sub-mirror 12 to the line sensor 6 shown in FIGS. 3 and 4 are attached to one unit main body 14. An infrared cut filter 15 and an anti-reflection member 16 are inserted between the sub-mirror 12 and the field mask 2, and the anti-reflection member 16 prevents light reflected from the surface of the infrared cut filter 15 from reaching the film 11. It is for the purpose of As will be explained in detail later, between the line sensor 6 and the unit body 14 that holds it, there is an adjustment member, that is, a fixed stage 17, consisting of a fixed member and a rotating member that contact each other at a contact surface inclined with respect to the optical axis. and a rotating stage 18 are interposed, and by rotating the rotating stage 8, the inclination of the line sensor 6 can be adjusted. In the illustrated case, the fixed stage 17 located near the line sensor 6 is coupled with the line sensor 6, but the fixed stage 17 may be formed integrally with the package of the line sensor 6. The unit body 14 is fixed to the front plate of the camera with mounting screws 19, the line sensor 6 is temporarily held on a fixed stage 17 with a sensor holding pin 20, and the field lens 3 is fixed to the unit body 14 with a field lens adjustment pin 21. It is designed to be adjustable.

Next, the assembly procedure of this focusing unit is shown by the arrow A in Fig. 5.
1, A2, A3-・Explain according to the procedure of fist.

A1: Attach the infrared cut filter 15 to the antireflection member 16.

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

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

A4: Insert the hole 16a of the anti-reflection member 16 into the unit body 14.
By press-fitting the cut filter 1 into the dowel 14a of
5 is assembled into the unit body 14.

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

6. The second diaphragm 4 is attached to the secondary imaging lens 5.

A7: The positioning portion 5C of the secondary imaging lens 5 is brought into contact with the unit main body 14, and the secondary imaging lens 5 is assembled into the unit main body 14 while being positioned in the rotational direction.

Step 8: Attach the fixed stage 17 to the line sensor 6.

A9: Attach the rotation stage 18 to the unit main body 14.

A10: The fixed stage 17 sandwiches the rotary stage 18, and the fixed stage 17 is assembled into the unit main body 14, and the protrusion 17a of the fixed stage 17 is inserted into the unit main body 14.
It is temporarily held by the engaging portion 14b.

Next, the adjustment procedure is shown in the arrows 81 to S9 (however, S3
(not shown). First, unit body 1
4 to the adjustment tool and adjust according to the following steps.

Sl: Insert the sensor holding pin 20 into the hole 6C of the line sensor 6.
and the notch hole 6d to regulate the position of the line sensor 6 with respect to the unit body 14.

S2: Extract the pupil, that is, align the optical axis between the focusing unit and the front plate of the camera body. Adjustments are made so that the apertures 4a and 4b of the diaphragm 4 are correctly projected into the exit pupil S of the machine lens 1 by the field lens 3. Actually, the field lens adjustment pin 21 is inserted into the hole 3a of the field lens 3.
Then, the field lens 3 is inserted into the notch hole 3b, and after the field lens 3 is parallel and decentered, it is fixed with an adhesive. The adjustment reference in this case uses a tool mirror box and a tool exit pupil.

S3: Although not shown, shading correction is performed using a uniform brightness surface chart, and the unevenness of the light amount on the line sensor 6 and the unevenness of the sensitivity of the line sensor 6 are collectively corrected using the EEFROM.

S4: Chuck the rotary stage 18 and rotate it around the X' axis, and move the line sensor 6 and fixed stage 17 together to
' Adjust the inclination of the line sensor 6 by swinging around the axis.
This adjustment method and principle will be described later with reference to FIG. After this adjustment, the fixed stage 17 and the rotating stage 18
Glue and fix.

S5: Pull out the sensor holding pin 20.

S6: Leave the rotation stage 18 chucking as it is, move the rotation stage 18 in parallel in the Y'-Z' plane, align the center of the line sensor 6 with the optical axis, and position the line sensor 6. A claw (not shown) that chucks the rotation stage 18 is capable of not only rotation but also slight movement in the Y' and Z' force 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 aligned in the 2° axial direction to adjust the glare.

Since the adjustment as a focusing unit is completed by the above steps S1 to S7, the focusing unit is removed from the adjustment tool and the next adjustment in S8.99 is performed.

S8: When attaching the focusing unit to the front plate of the camera,
In order to match the distance measurement center with the center of the distance measurement frame in the finder, the entire focusing unit is moved in the Y-axis direction to adjust the balax. In this case, since the mounting portion on the bottom surface of the front plate of the camera is provided with a groove that fits into the mounting seat 14e of the unit main body 14, the focusing unit is moved in parallel using this groove as a guide.

S9: After fixing the unit body 14 to the front plate of the camera with the mounting screws 19, set the focus of the focusing unit to EEF.
Match electrically using ROM.

The inclination adjustment of the line sensor 6 in step S4 described above and its principle will be explained in detail below. In FIG. 5, the concave surface 18a around the rotary stage 18 is chucked with a jig (not shown), and the rotary stage 18 is rotated around the X' axis.

In this case, the contact surfaces L7b and 18b of the fixed stage 17 and the rotary stage 18 are parallel to each other and inclined at a predetermined angle with respect to the optical axis. Further, since the rotation of the fixed stage 17 and the rotating stage 18 is restricted by the sensor holding pin 20, by rotating only the rotating stage 18, the fixed stage 17 and the rotating stage 18 can be rotated as a unit around the Y axis. The rotation is adjusted.

The principle is shown in FIG. 6(a). Since the contact surfaces 17b and 18b of the fixed stage 17 and the rotating stage 18 are inclined with respect to the optical axis as described above, the contact surface 18b
Let the inclination angle of the normal Nl be φ. It should be noted that at the initial position of the fixed stage 17, the normal line old is within the X'-Y' plane.

Here, when only the rotary stage 18 is rotated counterclockwise by an angle θ, the rotary stage 18 begins to tilt with respect to the optical axis as shown in FIG. It is represented by the inclination angle θy゛ of the normal line N2 from the optical axis. Note that the fixed stage 17 is shown swinging around the point C where the optical axis intersects the contact surfaces 17b and 18b, so the surface 17c is shifted by d2 in the Z'' axis direction. In reality, the fixed stage 17 and the rotary stage 18 are regulated by the sensor holding pin 2o, so the shift amount d2 is generated by the contact surface 17.
This is canceled out by the slippage in the Z'-axis direction between b and 18b, and the center of the line sensor 6 does not deviate from the optical axis.

The relationship between the angles θ and θy' described above is expressed as shown in FIG. 7(a). What should be noted here is that the normal line Nl has a tilt angle 02' around the Z' axis in addition to a tilt angle θy' around the Y° axis, but the actual adjustment range is Within this range, the tilt angle 02' is almost negligible compared to the tilt angle θy', and there is no practical problem.

Note that in the conventional case, there is only one rotation stage 18 and no fixed stage 17, and the line sensor 6 is connected to the rotation stage 1.
Since it is in direct contact with the contact surface tab of No. 8, there is an inclination of θ + = φ from the beginning, and this situation is shown in Figure 7 (b
). Here, in order to reduce the inclination angle 02', φ can be reduced, but in order to obtain the same inclination angle θy°, it is necessary to increase φ. Adjustment becomes difficult.

In addition, when a mirror is interposed between the secondary imaging lens 5 and the line sensor 6 as in the conventional example, by setting the inclination of this mirror to cancel out the inclination angle of 02°, the inclination can be reduced. Although the angle 02' can be made almost zero, in a system that does not use a mirror as in this embodiment, the only method is to also tilt the contact surface 17b of the fixed stage 17 that opposes the contact surface 18b of the rotary stage 18. .

The above-described embodiment may be modified so that the line sensor 6 is elastically held by the unit body 14 which is its holding member, and the fixed stage 17 may be rotated.
Alternatively, the fixed stage 17 may be eliminated, and the package surface of the line sensor 6 may be sloped parallel to the contact surface 18b, so that the line sensor 6 and the rotary stage 18 are brought into direct contact. Moreover, such contact surfaces 18b, 17b
There is no problem even if one side of the rotation stage 18 is discontinuous.Furthermore, the other side of the rotation stage 18 is tilted, and another fixed stage having an opposite slope is added, and the rotation stage 18
It is also possible to have a configuration in which the stage is sandwiched between two fixed stages.

[Effects of the Invention] As explained above, the optical TL adjustment device according to the present invention has the following effects:
When adjusting the line sensor in the longitudinal direction, there is almost no inclination in the direction perpendicular to the longitudinal direction, so the adjustment is easy and the distance measurement accuracy can be improved. Furthermore, by appropriately selecting the angle of the contact surface between the rotary stage and the fixed stage, the inclination angle θy° relative to the adjustment angle θ can be sensitively and arbitrarily adjusted. Furthermore, instead of chucking and rotating the line sensor itself, by chucking the rotary stage and rotating it together with the line sensor, the line sensor can be tilted, positioned, etc. without having to be chucked again.
Another advantage is that all adjustments such as rotation can be made.

[Brief explanation of drawings]

The drawings show an embodiment of the photoelectric adjustment device according to the present invention, and FIG. 1 is a basic configuration diagram, FIG. 2 is an explanatory diagram of distance measurement error, FIG. 3 is a sectional view inside the camera, and FIG. Figure 4 is a cross-sectional view of a part of it viewed from a different direction, Figure 5 is an exploded view of the specific structure of the focusing unit, Figure 6 is a principle diagram of sensor tilt adjustment, and Figure 7 is a quantification of the line sensor tilt. FIG. Symbol l is a photographing lens, 2 is a field mask, 3 is a field lens, 4 is an aperture, 5 is a secondary imaging lens, 6 is a line sensor, 7 is a quick return mirror, 12 is a submirror, 13 is a mirror, 14 is a unit In the main body, 15 is an infrared cut filter, 16 is an antireflection member, 17 is a fixed stage, and 18 is a rotating stage. Patent applicant: Canon Co., Ltd. Figure 2 Figure 3 Figure 4121 Figure 6 (b) Figure 7 (b)

Claims (1)

[Claims] 1. An adjustment member that contacts each other with a contact surface inclined with respect to the optical axis is interposed between a line sensor that receives a light beam and a sensor holding member that holds it, and the adjustment member is A photoelectric adjustment device characterized in that the inclination of the line sensor is adjusted by rotating it relative to a holding member. 2. The photoelectric adjustment device according to claim 1, wherein the adjustment member is formed in an annular shape to allow the light flux to pass through, and is fitted into a holding recess of the sensor holding member. 3. The adjusting member includes a fixed member located near the line sensor and a rotating member located far away, and the fixed member is coupled to the line sensor, according to claim 1. photoelectric adjustment device. 4. The photoelectric adjustment device according to claim 3, wherein the fixing member is coupled to the line sensor and resiliently held by the sensor holding member. 5. The photoelectric adjustment device according to claim 3, wherein the fixing member is integrated into the package of the line sensor.