JPH07104351A - Finder device for camera - Google Patents

Abstract

PURPOSE:To prevent the sticking of dust, etc., to the front surface of a Porroprism and a visual field frame varying means by arranging the front surface of the Porroprism and a finder visual field varying means in a tight closed space and adopting constitution that the finder visual field varying means is not a type that it is moved in an optical axial direction. CONSTITUTION:The Porroprism 9 is arranged in contact with the rear surface of a visual field plate 7 and the front surface faces the tight closed space in a lens holding frame 4 through the visual field window 7a of the visual field plate 7. Moreover, a visual field varying member 5 shields the top edge part of the window 4e of the holding frame 4 when a photographic picture is swiched to a panoramic one. A hole 6a relatively rotatably fitted into a fixing shaft 4b and an oblong hole 6b in a horizontal direction relatively rotatably fitted-into a pin 5b are provided to pass through the other finder visual field varying member 6 and it is supported to rock centering the fixing shaft 4b and driven by the member 5 via the fitting relation between the pin 5b and the oblong hole 6b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder device for a camera, and more particularly to a finder device for a camera having a screen size switching function configured to switch the field of view of the finder in conjunction with a change in the size of a shooting screen.

[0002]

2. Description of the Related Art Conventionally, as a real image type finder device for a camera having a photographing screen switching mechanism, for example, an actual flat screen 3-
A finder device disclosed in Japanese Patent Publication No. 98426 is known. The viewfinder device disclosed in this publication places a visual field frame conversion member in front of a Porro prism and moves the visual field frame conversion member in the optical axis direction to position two types of visual field frames on the real image plane. Is configured to change the viewfinder field range.

[0003]

In the viewfinder device disclosed in the above publication, the field frame conversion member moves in the optical axis direction between the viewfinder objective lens and the Porro prism. , The front surface of the Porro prism is exposed to the internal space of the camera, and the movement of the visual field frame conversion member in the optical axis direction makes it easy for dust to be sucked into the space by the pumping action. There was a drawback that dust easily adhered. Further, there is a drawback that the thickness of the camera is increased and a dead space is formed above the camera because a space is required for the member to move in the optical axis direction.

The object of the present invention is to provide a finder device which does not have the abovementioned disadvantages.

[0005]

In order to realize a finder device that does not have the above-mentioned drawbacks, the front surface of the Porro prism should not be exposed to the internal space of the camera, and the finder field varying means should move in the optical axis direction. It is necessary that it is not of a form. The present invention is constructed based on such an idea, and the viewfinder device of the present invention is arranged in a space where the front surface of the Porro prism and the viewfinder visual field changing means are substantially sealed, and the viewfinder visual field changing means. Is not a movable type in the optical axis direction. Therefore, in the finder device of the present invention,
There is no risk of dust or the like adhering to the front surface of the Porro prism or the visual field frame changing means.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numerals 1 to 3 are finder objective lenses, and the rearmost objective lens 3 is fixed to a lens holding frame 4 described later. Reference numeral 4 denotes a lens holding frame having a space inside, and a rectangular window 4e for fitting the rearmost objective lens 3 is provided through a front plate portion of the holding frame. On the rear surface of the holding frame 4, a field plate 7 serving as a back cover of the holding frame is fixed, and the holding frame 4 and the field plate 7 are fixed.
Field-of-view variable members 5 and 6, which will be described later, are arranged in a closed space formed between and. The holding frame 4 is attached to the field plate 7.
A field window 7a having the same size as that of the window 4e of the same is penetrated, and pin insertion holes 7b and 7c for inserting pins for fixing the field plate 7 to the holding frame 4 are provided. It is provided at the same position as the pin insertion holes 4d and 4c opened on the rear surface of the frame 4.

Reference numeral 9 denotes a Porro prism included in the eyepiece lens system of the finder optical system. The Porro prism 9 is disposed in contact with the rear surface of the field plate 7, and the front surface of the Porro prism 9 passes through the field window 7a of the field plate 7. It faces the closed space in the lens holding frame 4. On the front surface of the Porro prism 9, pins 9a and 9b for fixing themselves and the field plate 7 to the rear surface of the lens holding frame 4 are provided in a protruding manner.
Is inserted into the pin insertion hole 7b of the view plate 7 and the pin insertion hole 4d of the holding frame 4, and the pin 9b is inserted into the pin hole 7c of the view plate 7 and the pin hole 4c of the holding frame 4. Thus, the Porro prism 9, the field plate 7, and the lens holding frame 4 are integrated as one unit.

The lens holding frame 4 has a fixed shaft 4b protruding rearward in the optical axis direction and a rectangular hole 4a penetrating the bottom plate of the holding frame 4, and the fixed shaft 4b has a visual field described later. The hole 7d of the field plate 7 is inserted into the hole 6a of the variable member 6 and
Is inserted into the field plate 7 to connect the holding frame 4 and the member 6 so as to be rotatable about the fixed shaft 4b.

The first visual field changing member 5 is a member that serves to shield the upper edge of the window 4e of the holding frame 4 when the photographing screen is switched to the panoramic screen. A pin 5b having a horizontal side portion 5c for shielding and a vertical side portion 5d penetrating the hole 4a and protruding rearward from an upper portion of the vertical side portion 5d and a top portion of the vertical side portion 5d. And a spring receiving seat 5a that is formed.

On the other side of the viewfinder field changing member 6,
A hole 6b fitted into the fixed shaft 4b so as to be relatively rotatable, and a horizontal elongated hole 6 fitted in the pin 5b so as to be relatively slidable.
b is penetratingly provided, the member 6 is swingably supported about the fixed shaft 4b, and is driven by the member 5 through a fitting relationship between the pin 5b and the elongated hole 6b. It has become so.

A coil spring 8 is arranged in the space between the spring receiving seat 5a of the member 5 and the top plate of the lens holding frame 4, and the member 8 is biased vertically downward by the spring 8. The member 6 is urged to rotate clockwise around the hole 6a.

At a position immediately below the lens holding frame 4, a lever 1 which can swing around a fixed shaft 12 parallel to the optical axis of the lens.
0 is arranged, and a receiving seat 10b for receiving the lower end of the vertical side portion 5d of the member 5 is provided at an intermediate position of the arm portion of the lever 10.
Is formed, and the tip of the arm is in contact with the receiving seat 13a of the screen switching interlocking member 13 that interlocks with the shooting screen size switching operation. A ring portion 10a, which serves as a swing center of the lever 10, is fitted to a sleeve 11, and the sleeve 11 is fitted to a fixed shaft 12 so as to be relatively rotatable.

Reference numeral 14 is an eyepiece lens arranged at the rear position of the Porro prism 9.

Next, the operation of the movable portion of the finder apparatus of this embodiment will be described with reference to FIGS. 1, 3 and 4.

When the photographing screen of the camera (not shown) is set to the standard screen, the member 13 is stationary at the upper first position. At this time, as shown in FIG. The tip of the arm portion of the lever 10 is pushed up to bring the arm portion into a horizontal state, and the receiving seat 10b provided in the middle of the arm portion of the lever 10 has a vertical side portion 5 of the visual field changing member 5.
The lower end of d is pushed up by overcoming the downward biasing force of the spring 8. Therefore, the member 5 is moved vertically upward in the holding frame 4 using the hole 4a of the lens holding frame 4 as a guide, and the horizontal side portion 5c of the member 5 is retracted upward from the window 4e of the lens holding frame 4. The state shown in FIG. On the other hand, when the member 5 is pushed up by the lever 10, the pin 5 of the member 5
Since b also moves vertically upward, the other visual field changing member 6 is rotated counterclockwise in FIG. 1 about the fixed shaft 4b,
As a result, the member 6 retracts below the window 4e as shown in FIG. Therefore, the viewfinder screen (viewfinder field)
Is the size of the window 4e (that is, the standard screen).

On the other hand, when the photographing screen of the camera (not shown) is switched to the panoramic screen, the member 13 descends vertically downward from the position shown in FIG. 4 and moves to the position shown in FIG. The engagement between the tip of the part and the receiving seat 13a of the member 13 is released, and at the same time, the member 5 is pushed downward by the force of the spring 8. Then, the member 5 descends vertically downward using the hole 4a of the holding frame 4 as a guide, and the step portion 5e above the vertical side portion 5d of the member 5 contacts the hole edge (hole edge) of the hole 4a. When the member 5 stops descending,
The horizontal side portion 5c of the window shields the upper edge of the window 4e. Further, as the member 5 descends, the pin 5b imparts clockwise rotation about the hole 6a to the other member 6, so that the member 6 is placed at a position that shields the lower edge of the window 4e. As a result, the viewfinder view changes to a panoramic screen compatible view.

[0017]

As described above, in the finder device of the present invention, the finder field changing mechanism moves in the plane orthogonal to the optical axis, and the rear surface of the finder objective lens and the mechanism are substantially sealed. It is arranged in the closed space, the front surface of the Porro prism of the viewfinder eyepiece system is arranged in the closed space, and the like, there is no fear that dust or the like will be attached to the finder optical system, therefore, A finder device that does not have the drawbacks of conventional devices can be realized.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts of a finder device according to the present invention.

2 is a view of the device in an assembled state,
FIG.

FIG. 3 is a diagram showing a state in which the field of view of the apparatus is set to a panorama corresponding field of view.

FIG. 4 is a view showing a state in which the visual field of the apparatus is set to a standard screen corresponding visual field.

[Explanation of symbols]

1 to 3 ... Viewfinder objective lens 4 ... Lens holding frame 5, 6 ... Field of view changing member 7 ... Field of view plate 8 ... Coil spring 9 ... Porro prism 10 ... Lever 11 ... Sleeve 12 ... Fixed shaft 13 ... Screen switching interlocking member

Claims (1)

[Claims] 1. A lens holding frame for holding a lens of a finder optical system and having a space behind the lens, and a viewing window aligned with the lens are provided through the rear surface of the lens holding frame. A field plate which is fixed to close the space, a transparent optical member which is fixed to the rear surface of the lens holding frame together with the field plate and closes the field window, and inside the space of the lens holding frame. A viewfinder device for a camera, characterized in that the front view of the transparent optical member faces the closed space.