JP3241982B2 - Diopter correction mechanism of back focus control type AF camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a diopter correction mechanism for a back focus control type AF camera.

[0002]

2. Description of the Related Art The applicant of the present invention discloses a back focus control type AF camera, in which, when a movable body is driven by focusing, an eyepiece of a finder mechanism mounted on the movable body is moved with respect to a focus surface of a viewfinder whose diopter is corrected. A diopter correction mechanism that enables the diopter to be moved without changing the relative position, and enables the diopter correction by moving the movable eyepiece of the eyepiece lens unit by operating the diopter correction operating member regardless of the position of the movable body. (Japanese Patent Application No. 6-136995).

In a back focus control type AF camera, the viewfinder mechanism is mounted on a movable body in a fixed body frame and moves. When the movable body moves to the infinity side, the eyepiece retreats to the back, making it difficult to see. Also, when an external correction lens is attached for diopter correction, there is a disadvantage that the focusing operation makes it difficult to see due to a change in position between the eyepiece and the correction lens. According to the above proposal, diopter correction can be easily performed by an external operation irrespective of the position of the movable body, and diopter correction can be performed without becoming a load for focusing drive.

[0004]

However, the proposed mechanism uses a long gear in the direction of the optical axis, gears provided on an external operating member are meshed with the long gear, and an external gear is used for movement of the movable body. Since the gear provided on the operation member slides in the optical axis direction while meshing with the long gear, there is a problem that the movable body may come off depending on the applied force when moving. Further, there has been a demand for more efficient assembly work. An object of the present invention is to provide a diopter correction mechanism for a back focus control type AF camera that is easy to assemble and has a high mechanism reliability.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a diopter correction mechanism of a back focus control type AF camera according to the present invention comprises a fixed body including a photographing lens mount and an outer portion forming an appearance of the camera. A finder mechanism, a distance measuring mechanism, an exposure mechanism, and a film feeding mechanism disposed at the center of the optical axis of the light passing through the lens and guided upward by the mirror, and movable in the optical axis direction in the fixed body. A back focus control type autofocus camera that includes a movable body and brings a film opening surface of the movable body to a focal position by a driving mechanism, wherein an eyepiece section of the finder mechanism is operated by operating an external operation member provided on the fixed body side. Moving the movable eyepiece that composes the lens in the optical axis direction of the viewfinder with respect to the fixed eyepiece A guide shaft having one end fixed to the movable body side so as to be parallel to the optical axis of the finder mechanism, and meshed with the external operation member and rotated by operating the external operation member. And a first gear inserted into the guide shaft so as to slide the guide shaft for transmitting the rotational force to the guide shaft and sliding the guide shaft against the linear force in the optical axis direction, and one end of the guide shaft. A second gear fixed in the vicinity, a rack meshing with the second gear, and a guide groove extending in a direction oblique to the optical axis, and a direction perpendicular to the optical axis by rotation of the second gear; And a pin fixed to a frame supporting the movable eyepiece and fitted in the guide groove.

According to the present invention, in the above configuration, the cross-sectional shape of the guide shaft is a shape lacking a part of a circle, and the through hole in which the first gear fits into the guide shaft is formed by the circular hole. The shape is complementary to the shape lacking a part of. Further, in the present invention according to the configuration, the external operation member is a dial rotatably supported with respect to the fixed body,
It has a bevel gear at its tip and the first gear is a bevel gear, and the bevel gears mesh with each other.

[0007]

According to the above construction, when the movable body is moved, the guide shaft is slid without fear of the gear meshing with the external operation member coming off, and the reliability of the mechanism can be secured. Also, the assembling work becomes easy.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic side view showing a cross section of a part of a back focus control type AF camera to which a diopter correction mechanism according to the present invention is applied. Fixed body A
Is configured to include an outer case including an upper cover 14, a back cover, and the like, and a lens mount 21. On the other hand, the movable body B is slidably supported in the direction of the lens optical axis in the fixed body A by a slide rail mechanism (not shown), and can be moved from an infinity position to a closest position by a driving mechanism with a focusing operation.

The movable body B comprises a mirror box having a mirror 19 and a sub-mirror 20 therein, an exposure mechanism, a finder mechanism, a film feeding mechanism, and the like. The finder mechanism consists of a focus glass 18, a pentaprism 1
3, an eyepiece 23 including the diopter correction mechanism 5 and an eyepiece including the dustproof glass 12. When the movable body B moves along the optical axis, the eyepiece 23 including the diopter correction mechanism 5 moves in the upper cover 14 in parallel with the optical axis of the finder mechanism.

FIGS. 2 and 3 are right side views for explaining an embodiment of a diopter correcting mechanism according to the present invention, and show a state where the movable body has moved to the infinite position side and the closest position side, respectively. I have. FIG. 4 is a left side view for explaining an embodiment of the diopter correction mechanism according to the present invention, and is a diagram showing a state where the movable body has moved to the infinite position side. Each figure shows a diopter correction mechanism, a movable eyepiece and a fixed eyepiece of an eyepiece, a dustproof glass of an eyepiece, and a pentaprism.

The diopter adjustment dial 1 is rotatably supported by a diopter adjustment dial support 15 whose shaft 1a is attached to an upper cover 14, as shown in FIG.
A bevel gear 2 is attached to the tip of the shaft 1a, and the bevel gear 2 is engaged with the bevel gear 3. The guide shaft 4 has a shape in which a cross section thereof lacks a part of a circle as shown in FIG.
One end 4a is fixed to the movable body side. Guide shaft 4
Is parallel to the optical axis of the finder mechanism, and a gear 6 is fixed near one end 4a. Further, the bevel gear 3 has a through hole 3a having a shape complementary to a shape lacking a part of a circle,
The through hole 3a is fitted to the guide shaft 4 and is slidable in the optical axis direction.

The guide plate 8 has a rack 8a and a guide groove 8b extending obliquely with respect to the optical axis.
Is meshed with. The guide plate 8 moves up and down by the rotation of the gear 6. A cam follower pin 9 fixed to the movable eyepiece frame 16 is engaged with the guide groove 8b. FIG. 5 is a cross-sectional view of the eyepiece moving integrally with the pentaprism as viewed from above. The eyepiece section includes a fixed eyepiece 11 supported by a fixed eyepiece frame 17 and a movable eyepiece 10 supported by a movable eyepiece frame 16. The fixed eyepiece frame 17 is fixed to the pentaprism 13 a side that receives the pentaprism 13.

The fixed eyepiece frame 17 is provided with the lens mounting portion 1.
7a, a cylindrical portion 17b that can be fitted to the outer periphery of the movable eyepiece frame 16, and a key groove 17c provided on the outer peripheral surface of the cylindrical portion 17b in parallel with the optical axis. On the other hand, a key 16a is implanted on the outer peripheral surface of the movable eyepiece frame 16,
The key 16a is guided by the key groove 17c. The movable eyepiece frame 16 is slidable parallel to the optical axis in a state where rotation is prevented by the key groove 17c.

To adjust the diopter, the user turns the diopter adjustment dial 1 while looking at the subject from the eyepiece. In FIG. 2, when the diopter adjustment dial 1 is rotated rightward, the bevel gear 3 is rotated rightward via the bevel gear 2 when viewed from the arrow 24 direction. The rotation of the bevel gear 3 is transmitted to the guide shaft 4, and the gear 6 similarly rotates rightward. As a result, the guide plate 8 having the rack 8a meshing with the gear 6 moves downward, and the guide groove 8b moves downward. Therefore, the movable eyepiece 10 moves to the right in a direction in which the distance x between the fixed eyepiece 11 and the movable eyepiece 10 is reduced. The photographer completes the diopter correction by moving to the position where the focus is best. When the diopter adjustment dial 1 is turned to the left, the movable eyepiece 10 moves to the left.

FIG. 2 shows a state in which the movable body has been moved to the infinity side, but diopter correction can be similarly performed at other positions. When the movable body moves to the closest position side by the focusing drive, the guide shaft 4 slides in the through hole 3a of the bevel gear 3 without changing the distance between the fixed eyepiece 11 and the movable eyepiece 10 whose diopter has been adjusted. Therefore, the load does not become a load for the focusing drive, but is brought to a position as shown in FIG. In the above description of the embodiment, an example in which the cross section of the guide shaft has a shape lacking a circle has been described. , For example, a polygon, a semicircle, or the like.

[0016]

As described above, according to the present invention, when the movable body is moved, the guide shaft is slid without the possibility that the gear meshing with the external operation member, which is the diopter correction dial, comes off. The reliability of the diopter correction function can be ensured.
In addition, since the guide shaft and the gear fitted to the guide shaft are not detached from the mechanism, there is an advantage that the assembling work is facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a cross section of a part of a back focus control type AF camera to which a diopter correction mechanism according to the present invention is applied.

FIG. 2 is a right side view for describing an embodiment of a diopter correction mechanism according to the present invention, and is a diagram illustrating a state where a movable body has moved to an infinite position side.

FIG. 3 is a right side view for explaining an embodiment of a diopter correction mechanism according to the present invention, and is a diagram showing a state where a movable body has moved to a closest approach position side.

FIG. 4 is a left side view for describing an embodiment of a diopter correction mechanism according to the present invention, and is a diagram illustrating a state where a movable body has moved to an infinite position side.

FIG. 5 is a cross-sectional view of the eyepiece that moves integrally with the pentaprism when viewed from above.

FIG. 6 is a rear view showing an upper cover in a cross section for explaining an installation position of a diopter correction dial.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Diopter adjustment dial 2, 3 ... Bevel gear 4 ... Guide shaft 5 ... Diopter correction mechanism 6 ... Gear 8 ... Guide plate 8a ... Rack 9 ... Cam follower pin 10 ... Movable eyepiece 11 ... Fixed eyepiece 12 ... Eyepiece Dustproof glass 13 ... Pentagon prism 14 ... Top cover 15 ... Diopter adjustment dial support 16 ... Movable eyepiece lens frame 17 ... Fixed eyepiece lens frame 18 ... Focus glass 19 ... Mirror 20 ... Sub mirror 21 ... Lens mount 22 ... Mirror box 23 ... Eyepiece

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-128572 (JP, A) JP-A-53-149324 (JP, A) JP-A-6-3571 (JP, A) JP-A 53-149 107820 (JP, A) JP-A-8-6116 (JP, A) JP-A-2-29029 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 13/00-13 / 32

Claims (3)

(57) [Claims] 1. A fixed body including a photographing lens mount and an outer part forming an appearance of a camera, a finder mechanism and a distance measuring mechanism arranged at the center of an optical axis of light passing through the lens and guided upward by a mirror. And a movable body having an exposure mechanism and a film feeding mechanism, the movable body being movable in the optical axis direction in the fixed body, and a drive mechanism for bringing a film opening surface of the movable body to a focal position. In the camera, a mechanism for adjusting a diopter by moving a movable eyepiece constituting an eyepiece part of the finder mechanism with respect to the fixed eyepiece in the optical axis direction of the finder by operating an external operation member provided on the fixed body side. A guide having one end fixed to the movable body side so as to be parallel to the optical axis of the finder mechanism. And meshed with the external operation member, rotated by the operation of the external operation member, and transmitted the rotational force to the guide shaft, and slid the guide shaft against the linear force in the optical axis direction. A first gear inserted through the guide shaft; a second gear fixed near one end of the guide shaft; a rack meshing with the second gear and a guide extending obliquely to the optical axis. A guide plate having a groove and moving in a direction perpendicular to the optical axis by rotation of the second gear; and a pin fixed to a frame supporting the movable eyepiece and fitted in the guide groove. Back focus control system A characterized by
Diopter correction mechanism of F camera. 2. The guide shaft according to claim 1, wherein a cross-sectional shape of the guide shaft is a shape lacking a part of a circle, and a through-hole in which the first gear fits with the guide shaft is formed in one of the circles. A diopter correction mechanism for a back focus control type AF camera, wherein the diopter correction mechanism has a shape complementary to a shape lacking a portion. 3. The external operation member according to claim 1, wherein the external operation member is a dial rotatably supported by the fixed body, and has a bevel gear at a tip end thereof and the first gear is a bevel gear. A diopter correction mechanism for a back focus control type AF camera, wherein the bevel gears mesh with each other.