JP2010256474A - Interchangeable finder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that it is necessary to suppress development cost, because an optical finder is merely a secondary accessory and its demand is restricted in a digital camera having an LCD, but the optical finder uses a lens having different lens constitution by viewing angle and having different curvature in many cases, so that it is very difficult to make a component for suppressing the development cost common. <P>SOLUTION: By disposing an abutting part that abuts on one point on a surface of an end of the lens inside a lens frame constituting the finder, the lens having different curvature and viewing angle is held by the same lens frame. Thus, the component constituting the finder is made common. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a lens holding structure of a replaceable optical viewfinder attached to a photographic camera, and more particularly to the shape of an abutting surface of an optical glass lens incorporated in the replaceable viewfinder.

Conventionally, a film camera not having a single-lens reflex structure has required an optical viewfinder for confirming the composition of a photograph. In particular, in a camera in which a lens can be exchanged, it is common to check the photographing composition using an exchangeable optical viewfinder that matches the angle of view of the lens.

In recent compact digital cameras, the need for an optical viewfinder has decreased because many images to be taken are directly displayed on the camera built-in LCD. However, some high-performance digital cameras are provided with an optical viewfinder in order to avoid the shutter release delay caused by the “time lag with the subject” that the LCD display inevitably has. In particular, when a camera with a replaceable lens and a camera with a plurality of angles of view are included in the product lineup, it is efficient to prepare an interchangeable viewfinder as with an old film camera.

In addition, in a camera equipped with an interchangeable viewfinder, it was necessary to replace the interchangeable viewfinder according to the focal length or angle of view of the interchangeable lens attached to the camera. It is shown in Document 1.

JP 2002-040522 A

However, in a digital camera having an LCD, the optical viewfinder is only a secondary accessory and demand is limited, so it is necessary to reduce development costs. However, as described above, there are many cases where the optical viewfinder has a different lens configuration for each angle of view, and it is very difficult to share parts for suppressing development costs.

In order to solve the above problem, an optical lens and a lens frame are used in common, and only the image frame for determining the angle of view is changed. In this case, the angle of view of the viewfinder can be freely changed by changing the image frame, but the viewfinder magnification is constant, so if the angle of view is narrowed, the image frame becomes relatively small, making it difficult to see the subject. There was a problem.

In addition, there is an example in which the lens used is made of transparent plastic that is injection-molded instead of polished glass, and the lens frame is shared by increasing the degree of freedom of shape of the lens itself. However, using an injection-molded plastic lens with a high mold cost for an interchangeable viewfinder with low demand has led to an increase in development cost, and as a result, it has been difficult to reduce the cost. In addition, it is difficult to reduce the size of plastic lenses.

A first invention made to solve the above problems includes at least one lens, a lens frame for holding the lens, and a connection part for attaching the lens frame to an accessory shoe of a camera. Another object of the present invention is to provide an interchangeable viewfinder characterized in that the lens frame can hold lenses having different curvatures.

A second invention made to solve the above problem is to provide an interchangeable finder according to claim 1, wherein the lens frame has a structure in which at least one lens is sandwiched.

According to a third aspect of the invention for solving the above-described problem, at least one lens held in the lens frame is pressed against either the subject direction or the photographer direction inside the lens frame by an elastic member. It is providing the exchangeable finder of Claim 1 or 2 characterized by the above-mentioned.

4. The interchangeable finder according to claim 1, wherein the lens frame includes a member for holding lenses having different curvatures. Is to provide.

5. The interchangeable finder according to claim 4, wherein the fifth invention made in order to solve the above-mentioned problem is that the member abuts at one point on the end surface of the lens and holds the lens. Is to provide.

In the interchangeable viewfinder of the present invention, a lens having a different curvature and angle of view can be held by the same lens frame by molding a contact portion that contacts one point on the lens end surface inside the lens frame. It becomes.

Further, by dividing the plastic lens frame having these two types of contact surfaces into two parts and holding the lens from above and below, the lens can be easily held and the assembly workability can be improved.

Furthermore, when the lens configuration is a two-group configuration divided into front and rear, an elastic member is disposed between the two lens elements, and the lens is pressed against the front and rear ends inside the lens frame using this elastic force. Thus, a viewfinder that is easy to assemble and has no lens holding backlash can be obtained.

It is an external view of the exchangeable viewfinder according to the present invention. The lower part of the interchangeable viewfinder is shown. It is sectional drawing of the said interchangeable finder. It is sectional drawing of the said interchangeable finder. It is an enlarged view of the lens contact part of FIG. It is an enlarged view of the lens contact part of FIG. It is an enlarged view of the contact part at the time of the lens from which a curvature differs contacting the contact part. It is the figure by which the elastic member was arrange | positioned in the said interchangeable finder.

Embodiments of the interchangeable viewfinder according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of a replaceable viewfinder according to the present invention. FIG. 2 shows the lower part of the interchangeable finder, and FIGS. 3 and 4 show sectional views of the interchangeable finder. 5 is an enlarged view of the lens contact portion of FIG. 3, and FIG. 6 is an enlarged view of the lens contact portion of FIG. FIG. 7 is an enlarged view of the abutting portion when lenses having different curvatures are abutting against the abutting portion. FIG. 8 is a view in which a rubber elastic member is disposed in the interchangeable viewfinder.

As shown in FIG. 1, the lens frame 1 is an upper lens frame and the lens frame 2 is a lower lens frame when the interchangeable viewfinder is vertically divided. The lens frames are fastened to each other by screws 5 and 6. In this embodiment, the lens frames 1 and 2 are fastened with screws. However, the present invention can be realized by fastening by bonding or welding.

As shown in FIG. 2, a connecting member 3 for attaching the interchangeable viewfinder to an accessory shoe of the camera is fastened to the lens frame 2 by four screws 7, 8, 9 and 10.

The internal structure of the interchangeable viewfinder is as shown in FIGS. 3 and 4, and each has a different lens configuration.

As shown in FIG. 3, glass lenses L 1, L 2, L 3, L 4 and L 5 are arranged inside the lens frames 1 and 2. Further, an image frame (not shown) for determining the angle of view is deposited on L4.

Each of the lens frames 1 and 2 has contact portions 1a, 1b, 1c and 1d for holding the lens therein, and the lens L5 is brought into contact with each of the contact portions by bringing the lens L5 into contact therewith. Holds within the frame.

As shown in FIG. 4, the interchangeable finder has a lens configuration that is different from the lens configuration shown in FIG. 3 and has glass lenses L6, L7, L8, L9, and L10. The lens frame is composed of the same lens frames 1 and 2 as in FIG. 3, and the lens L10 is in contact with 1a, 1b, 1c and 1d. Further, an image frame (not shown) for determining the angle of view is deposited on L9.

As shown in FIGS. 5 and 6, the contact portions 1 a, 1 b, 1 c, and 1 d abut at one point on each lens end surface.

  Further, as shown in FIG. 7, even if lenses having different curvatures are provided, the lens frames 1 and 2 can hold the lenses. A broken line portion is a lens beam transmitted through each lens, and each contact portion is outside the lens beam.

The lenses L1 to L4 and the lenses L6 to L9 also have a lens configuration with different curvatures and lens thicknesses, but each lens is mechanically placed in the lens frames 1 and 2 by interposing the elastic material 4 between the lenses. Fixed stably in structure.

Further, as shown in FIG. 8, when the lens configuration is a two-group configuration divided front and rear, a rubber elastic member 11 having an angular cross section is arranged between the two lenses L11 and L12, and the member has Using the elastic force, each lens is brought into pressure contact with both ends of the lens frames 1 and 2 on the subject side and the photographer side. This makes it possible to obtain an interchangeable finder that is easy to assemble and has a lens fixed stably in terms of mechanical structure.

The same effect can be obtained even if the rubber elastic member 11 is changed to a coil spring or a leaf spring.

At this time, the surface of the lens to be abutted is a spherical surface or a flat friction surface.

As described above, it is possible to hold lenses having different curvatures and angles of view by the same lens frame by molding a contact portion that contacts one point on the lens end surface inside the lens frame.

In addition, the shape, material, and arrangement position of the contact portion are not limited to the present embodiment. The present invention can be implemented in various modes without departing from the gist of the present invention.

1 Lens frame 1
2 Lens frame 2
3 connecting member 4 elastic material 5 screw 6 screw 7 screw 8 screw 9 screw 10 screw 11 rubber elastic member L1 lens L2 lens L3 lens L4 lens L5 lens L6 lens L7 lens L8 lens L9 lens L10 lens L11 lens L12 lens

Claims (5)

At least one lens,
A lens frame for holding the lens;
In the interchangeable finder having a connection part for attaching the lens frame to the accessory shoe of the camera,
The interchangeable viewfinder characterized in that the lens frame can hold lenses having different curvatures. The interchangeable finder according to claim 1, wherein the lens frame has a structure in which at least one lens is sandwiched. The at least one or more lenses held in the lens frame are pressed against either the subject direction or the photographer direction inside the lens frame by an elastic member. Interchangeable viewfinder. The interchangeable finder according to any one of claims 1 to 3, wherein the lens frame has a member for holding lenses having different curvatures. The interchangeable finder according to claim 4, wherein the member abuts at a point on the end surface of the lens and holds the lens.

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