JPH11183970A - Parallax adjusting mechanism for albada type finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parallax adjusting mechanism for an Albada type finder constituted so that parallax can be reliably adjusted. SOLUTION: This parallax adjusting mechanism is equipped with a frame body having a nearly rectangular aperture 16 housing a nearly rectangular ocular L3 having an optical frame pattern. One screw element 22 is screwed on one side of the frame body and abuts on the corresponding side of the ocular. Two screw elements 24 and 26 are screwed on the side adjacent to the above- mentioned side of the frame body and abut on the corresponding side of the ocular. A nearly V-shaped spring element 28 is provided between two remaining sides on which the screw elements do not abut and the angle part of the aperture 16 corresponding to the angle part between the two sides. Two leg parts of the spring element 28 are engaged to freely slide on the two remaining sides, and the acute angle part thereof is engaged to turnably slide on the angle part of the aperture 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallax adjusting mechanism inevitably associated with a camera having a photographing optical system and a finder optical system, and more particularly to a parallax adjusting mechanism of an Albada finder.

[0002]

2. Description of the Related Art As is well known, in a camera having an Albada finder optical system and a photographing optical system, a shift between the visual field of the photographing optical system and the visual field of the finder optical system, that is, so-called parallax, is inevitable. Accompanying. However, there is a location where the field of view of the photographing optical system and the field of view of the finder optical system match each other, and this location is set, for example, 0.6 m ahead of the camera.

On the other hand, two light frames are observed in the field of view when looking through the eyepiece of the finder optical system, and one light frame is large and the other light frame is small. The larger light frame is used when the photographer photographs a subject at least 0.6 m from the camera, and the smaller light frame is used when the photographer photographs a subject within 0.6 m from the camera. In this way, the deviation between the field of view of the photographing optical system and the field of view of the finder optical system is minimized.

When assembling a camera as described above, the eyepiece of the finder optical system must be moved so that the field of view of the photographing optical system and the field of view of the finder optical system coincide with each other at a position 0.6 m ahead of the camera. Fine adjustment is required in a plane perpendicular to the optical axis. As a conventional parallax adjusting mechanism, screw elements are screwed onto four sides of a substantially rectangular frame body for accommodating an eyepiece of a finder optical system, and the screw elements are brought into contact with the sides of the eyepiece. There is known a method in which a parallax adjustment is performed by finely moving an eyepiece, and then the eyepiece is adhered and fixed to a frame.

[0005] However, in the above case, when the field of view of the photographing optical system and the field of view of the finder optical system cannot accurately coincide with a position 0.6 m ahead of the camera due to environmental changes and aging. The problem is that parallax adjustment cannot be performed again.

Therefore, one screw element is screwed onto one of two adjacent sides of one of the frame members to make contact with the corresponding side of the eyepiece, and one of the two adjacent sides of the frame member is connected to one of the two adjacent sides. Two screw elements are screwed into the other of the two sides to abut on the corresponding side of the eyepiece, and the other two sides adjacent to each other of the frame body and the side of the eyepiece corresponding to those sides. With a spring element interposed between each side and
It has been proposed to perform parallax adjustment by appropriately moving the above-mentioned screw element.

[0007]

Such a parallax adjusting mechanism has an advantage that the parallax adjustment can be repeatedly performed, but has a disadvantage that the adjustment cannot be performed reliably. In particular, during fine movement of the eyepiece, it can happen that the spring element is simply elastically deformed without relative sliding movement between the spring element and the eyepiece due to friction. afterwards,
When the elastic force due to the elastic deformation applied to a certain beat is released, a relative displacement occurs between the spring element and the eyepiece, and the parallax adjustment is shifted.

Accordingly, an object of the present invention is to provide a parallax adjustment mechanism of the type described above, which is configured to perform highly reliable parallax adjustment. .

[0009]

The parallax adjusting mechanism of the Albada finder according to the present invention adjusts parallax by movably holding a substantially rectangular eyepiece having a light frame pattern. A frame having a substantially rectangular opening for accommodating the lens, and a frame 1 screwed to one of two mutually adjacent sides of the frame and brought into contact with the corresponding side of the eyepiece. Two screw elements, two screw elements screwed to the other of the two adjacent side sides of one of the frames and brought into contact with the corresponding side sides of the eyepiece, and four screw sides of the eyepiece. A substantially V provided between the remaining two sides that are not brought into contact with the screw element and the corner of the substantially rectangular opening corresponding to the corner between the two sides.
A substantially V-shaped spring element, wherein two legs of the substantially V-shaped spring element are slidably engaged with the remaining two sides of the eyepiece, and a corner of the substantially V-shaped spring element is substantially rectangular. Are rotatably slidably engaged with the corresponding corners of the opening.

[0010] In the parallax adjusting mechanism according to the present invention, preferably, each tip of both legs of the V-shaped spring element is bent or curved so as to be deviated outward, and the bent or bent portion is formed. Are slidably engaged with the corresponding side of the eyepiece.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a parallax adjusting mechanism for an Albada finder according to the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, there is shown an example of an Albada finder optical system. As shown in the figure,
The Albada finder optical system comprises a first lens L1 having negative power, a second lens L2 having negative power, and a substantially rectangular eyepiece L3 having positive power. These lenses L1, L2 and L3 Are arranged in order from the object plane O to the eye E of the photographer.

As shown in FIG. 2, the eyepiece L3 has a convex surface and a flat surface, and the convex surface faces the photographer's eye E. The flat surface of the eyepiece L3 has a first optical frame pattern P1, Second light frame pattern P2 and ranging frame pattern P
3 is formed by vacuum depositing a suitable metal material. On the other hand, one concave surface of the second lens 2, that is, the concave surface facing the eyepiece L3 is formed as a half mirror.

Therefore, when the external light is incident on the flat surface side of the eyepiece L3, a part of the external light is, as shown in FIG.
Is reflected by the light frame pattern P1, the second light frame pattern P2, and the distance measurement frame pattern P3, and then is reflected again by the concave surface of the second lens, and then passes through the eyepiece L3. Thus, the first light frame pattern P1, the second light frame pattern P2, and the distance measurement frame pattern P3 as shown in FIG. 3 appear in the field of view of the photographer looking through the eyepiece L3.

Referring to FIG. 4, the viewing angle or field angle of the photographing optical system is indicated by a solid line, and the viewing angle or field angle of the finder optical system is indicated by a broken line. As shown in the figure, the difference between the angle of view of the photographing optical system and the angle of view of the finder optical system is called so-called parallax.
Both angles of view are matched at a position 0.6 m ahead. When the photographer shoots an object more than 0.6m away from the camera, the first
When the photographer shoots a subject within 0.6 m from the camera, the light frame (P1)
(P2), that is, the smaller light frame is used. In this way, the first light frame (P1) and the second light frame (P2) are set so that the deviation between the field of view of the photographing optical system and the field of view of the finder optical system is kept as small as possible.

However, as described above, when assembling the camera, in order to make the angle of view of the photographing optical system and the angle of view of the finder optical system exactly coincide with the position 0.6 m ahead of the camera,
It is necessary to finely adjust the eyepiece of the finder optical system in a plane perpendicular to its optical axis.

Referring to FIG. 5, there is shown a parallax adjustment mechanism according to the present invention. In FIG.
Indicates a frame frame, and the frame frame 10 forms a part of a camera frame. The frame 10 comprises a lower frame 12 and an upper frame 14 which can be detachably attached to the lower frame 12. When the two frame portions 12 and 14 are assembled, a frame for accommodating the eyepiece L3 is formed, and a substantially rectangular opening 16 is defined by the frame.

An eyepiece L3 is disposed in the opening 16 of the frame, and each of the left and right sides of the eyepiece 3 has an ear 1 projecting therefrom as shown in FIGS.
8 and 20 are provided. The ears 18 and 20 may be integrally formed from the same optical glass as the eyepiece L3, or the ears 18 and 20 may be formed separately, in which case the ears 18 and 20 Is appropriately adhered to the lateral side of the eyepiece L3.

As shown in FIG. 5, a screw element 22 is screwed to one of two adjacent sides, that is, a lower side, of one of the frame members defining the substantially rectangular opening 16. To make contact with the corresponding side of the eyepiece L3, that is, the lower side. On the other hand, two screw elements 24 and 26 are screwed to the other of the other two adjacent sides of the frame that defines the substantially rectangular opening 16, that is, the left side, and the eyepiece L
3 is brought into contact with the corresponding side, that is, the left side.

Of the four sides of the eyepiece L3, the remaining two sides which are not brought into contact with the screw elements 22 and the screw elements 24 and 26, and the corners corresponding to the corners between the two sides. A substantially V-shaped spring element 28 is provided between the rectangular opening 16 and the corner. As can be seen from FIG. 5, the tips of both legs of the substantially V-shaped spring element 28 are bent so as to deviate outwardly, and each leg is bent at the point of the bending and the remaining two sides of the eyepiece. Is slidably engaged with a corresponding one of the sides. That is, the bent portion of the upper leg portion of the substantially V-shaped spring element 28 is slidably engaged with the upper side of the eyepiece L3, and the bent portion of the lower leg portion is located on the right side of the eyepiece lens 3. It is slidably engaged with the ear 18 on one side. On the other hand, the sharp corner of the substantially V-shaped spring element 28 is rounded, and the rounded corner is rotatably slidably engaged with the corresponding corner of the substantially rectangular opening 16. .

In the embodiment shown in FIG. 5, the bent portion of the lower leg of the substantially V-shaped spring element 28 corresponds to the eyepiece L3.
Is slidably engaged with the ear 18 on the right side of
However, if necessary, the ear portion 18 may be omitted and the bent portion may be directly slidably engaged with the eyepiece L3 on the right side.

In the above-described parallax adjusting mechanism, when the parallax adjustment is performed by moving any of the screw elements 22, 24 and 26, the substantially V-shaped spring element 28 is used.
Both legs are elastically deformed in response to the movement of the eyepiece L3. At this time, the substantially V-shaped spring element 28 itself can rotate in such a manner as to be centered on the rounded corner. That is, at the time of parallax adjustment, the substantially V-shaped spring element 2
Numeral 8 not only undergoes elastic deformation but also follows the movement of the eyepiece L3 by its rotational movement.

For example, when the screw element 22 is moved so as to be screwed, the eyepiece L3 is displaced upward. At this time, the substantially V-shaped spring element 28 is moved clockwise about its rounded corner. Because it can be rotated,
The movement or displacement of the eyepiece L3 is substantially V-shaped spring element 28.
It is not absorbed by its elastic deformation alone without the rotational movement of. Therefore, a situation in which a relative displacement occurs between the eyepiece L3 and the substantially V-shaped spring element 28 after the parallax adjustment can be avoided.

Preferably, a suitable lubricant may be applied to minimize the friction between the engaging portions of the substantially V-shaped spring elements, and a low-friction material may be applied to necessary parts. It can be coated. Also, in the above embodiment,
The tips of both legs of the generally V-shaped spring element 28 are bent outwardly, but it is also possible to simply curve the tips away. On the other hand, approximately V
The distal ends of the two legs of the U-shaped spring element 28 may be engaged so that they do not bend or bend outwardly, but instead abut against the sides of the eyepiece L3. It is possible, at this time, preferably the tip is rounded.

[0025]

As is apparent from the above description, in the parallax adjusting mechanism according to the present invention, when the parallax is adjusted, the substantially V-shaped spring element is not only elastically deformed but also rotated by its rotational movement. Since the lens follows the movement of the lens, highly reliable parallax adjustment can be performed, and a situation in which the parallax adjustment is performed again can be avoided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an Arbada finder optical system to which a parallax adjusting mechanism according to the present invention is applied.

FIG. 2 is a partially enlarged perspective view showing an eyepiece of the Albada finder optical system of FIG. 1 together with a negative lens associated therewith.

FIG. 3 is a view showing only a light frame in a visual field seen through the Albada finder of FIGS. 1 and 2;

FIG. 4 is a schematic diagram for explaining parallax adjustment of a camera.

FIG. 5 is a sectional view showing a parallax adjusting mechanism according to the present invention.

FIG. 6 is a plan view of an eyepiece incorporated in the parallax adjustment mechanism of FIG. 5;

FIG. 7 is an elevation view of the eyepiece of FIG. 6;

[Explanation of symbols]

 L1 First lens L2 Second lens L3 Eyepiece P1 First light frame pattern P2 Second light frame pattern P3 Distance measurement frame pattern 10 Frame frame 12 Lower frame frame portion 14 Upper frame frame portion 16 Opening 18 Reference Signs List 20 ears 22, 24, 26 screw element 28 substantially V-shaped spring element

Claims (3)

[Claims] 1. A parallax adjustment mechanism of an Albada finder for movably holding a substantially rectangular eyepiece having a light frame pattern and performing parallax adjustment, wherein the substantially rectangular eyepiece accommodates the eyepiece. A frame having an opening having a shape, one screw element screwed to one of two adjacent sides of one of the frames and brought into contact with a corresponding side of the eyepiece; Two screw elements screwed to the other of the two adjacent sides of one of the bodies and brought into contact with the corresponding sides of the eyepiece; and the screw elements among four sides of the eyepiece. A substantially V-shaped spring element provided between the remaining two sides that are not brought into contact with the opening and the corners of the substantially rectangular opening corresponding to the corners between the two sides. The two legs of the substantially V-shaped spring element are connected to the eyepiece. The other two sides are slidably engaged with each other, and the acute angled corner of the substantially V-shaped spring element is slidably engaged with the corresponding corner of the substantially rectangular opening. A parallax adjustment mechanism characterized by the following. 2. The parallax adjusting mechanism according to claim 1, wherein each end of each of the legs of the V-shaped spring element is bent so as to be deviated outward, and the bent portion is formed on the eyepiece. A parallax adjustment mechanism which is slidably engaged with a corresponding side. 3. The parallax adjusting mechanism according to claim 1, wherein each of the distal ends of both legs of the V-shaped spring element is curved so as to be deviated outward, and the curved portion is provided on the eyepiece. A parallax adjustment mechanism slidably engaged with the corresponding side.