JPS6132829A - Bifocal camera - Google Patents

Abstract

PURPOSE:To minimize the movement extent and therefore obtain a lens barrel which operates easily and is compact in structure by mounting and demounting a conversion lens in an upper space including the optical path of a main lens for photography. CONSTITUTION:The lens barrel 2 is pressed and sunk toward the camera body, i.e. image frame 20 until it stops, and then an abutting piece 13c fitted atop of a lever 13 is pressed against an abutting material 21 provided to the camera body or its fixed part in the process of said depressing operation. When the sinking is completed, the lever 13 rotates counterclockwise against a torsion spring 8. The clockwise rotation of a gear 11 rotates a gear 10 counterclockwise against the torsion spring 8, so a swinging member 7 is rotated counterclockwise to move to under an optical axis 3a and enter the space 2a in the lens barrel 2. Namely, the conversion lens 6 moves away from the optical path of a main lens 3 for photography completely together with the swinging member 7 which holds the conversion lens and is stored.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bifocal camera in which a switching device for switching the focal length of the main lens for photographing to a bifocal length is improved. .

[Prior art]

Conventionally, the method of switching the focal length of the main lens for photography in a bifocal camera is to insert a conversion lens behind the main lens for photography in conjunction with the movement of pulling out the lens barrel from the camera body, and to change the focal length of the main lens for photography. Measures are taken to change the composite focal length of the camera and match the focal position to the film plane of the camera.

In such a bifocal camera, when taking pictures using only the main lens for photography, the lens barrel is used in a state that is pushed into the camera body, that is, in a retracted state. It is necessary to completely escape from the optical path of the lens and retreat within the lens barrel.

In general, the conversion lens can be inserted and removed from the main photography lens by sliding it horizontally, or by sliding it horizontally.
Another method is to attach and detach the conversion lens by undulating it back and forth in the optical axis direction, but in the former case, a large amount of movement is required for the conversion lens to escape from the optical path in the longitudinal direction of the screen. The disadvantage is that the volume becomes large, making it impossible to make the lens barrel more compact.

In the latter case, a large space must be provided behind the main photography lens to allow the conversion lens to rise and fall back and forth, which limits the focal length of the main photography lens and, in addition, increases the length of the lens barrel. This was a major obstacle to miniaturizing cameras.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to minimize the amount of movement of a conversion lens required to change the focal length of the main lens for photographing, thereby providing a bifocal camera that is easy to operate and equipped with a compact lens barrel. This is what I did.

[Structure of the invention]

The present invention provides a lens barrel of a bifocal camera in which a conversion lens is disposed at the rear lower part of the main lens for m-shading so as to be movable in a direction perpendicular to the optical axis. When the conversion lens is pulled out, the elastic member is biased to position it in the optical path, and when it is retracted into the camera body, it comes into contact with the camera body or a fixed part of the camera and is forcibly rotated. The conversion lens is configured to be retracted to the lower part outside the optical path by the action of a rod, and the conversion lens is inserted into and removed from the image-forming side optical axis of the main lens for photography in the direction perpendicular to the optical axis inside the lens barrel. In a bifocal camera that changes the focal length of the main photographic lens by
This is achieved by a bifocal camera characterized in that the conversion lens is inserted and removed within a lower space that includes the optical path of the main photographic lens.

〔Example〕

The lens barrel of a bifocal camera according to the present invention is shown in FIGS. 1 and 4, and its main parts are shown in FIGS. 2 and 3.

In the figure, l denotes a lens barrel base fixed to the front part of the camera body (not shown), and 2 denotes a lens mirror that fits inside the lens barrel base 1 and is attached so that it can be slid back and forth and pulled out or collapsed as shown. It is the torso.

3 is a main lens for photographing, and 4 is a shutter, which is controlled from the camera body through mechanical or electrical means.

Reference numeral 5 denotes a light-shielding frame surrounding the optical path of the main photographic lens 3; 6 denotes a retconversion lens disposed between the shutter 4 and the light-shielding frame 5; its optical axis is parallel to the optical axis 3a of the main photographic lens 3; It is placed so that it coincides with the extension line.

Reference numeral 7 denotes a swinging member for holding the conversion lens 6, which is pivotally attached to a mounting board (not shown) of the shutter 4;
Although it is biased clockwise by the torsion spring 8, it comes into contact with a stomp pin 9 which is also implanted in the mounting board and is stopped.

Reference numeral 10 denotes a gear attached to the swinging member 7 with its rotation center coinciding with another gear 1, which is also pivotally attached to the mounting board.
It meshes with 1.

Reference numeral 12 denotes a lever A which is integrally mounted several times so that its center of rotation coincides with the gear 11, and its left end surface is formed into a circular arc shape in cross section.

Reference numeral 13 denotes a stack rod that is pivoted on the projection member 4a on the mounting board, and is biased counterclockwise by a torsion spring 14, which has a significantly greater biasing force than the torsion spring 8. Since it is set to be small, the stacking rod 13 is installed on a shaft seat 13a formed integrally with it.
3ti is stopped at the illustrated position by contacting the lever A12 in a perpendicular manner. Note that the left end surface of the lever B13b has a circular arc-shaped cross section, similar to the lever A12, so that even when pressed strongly, the operation is transmitted smoothly and accurately.

The state described above shows the state in which the lens barrel 2 is pulled out from the camera body, the conversion lens 6 is inserted into the optical path, and the focal length of the main photographic lens 3 is changed by synthesis. The focused image is correctly formed on a film (not shown) surface facing the image frame 20 of the camera body.

Next, the conversion lens 6 is retracted out of the optical path,
The process of returning to the photographing state using only the photographing main lens 3 will be explained.

When the lens barrel 2 is depressed and retracted from the state shown in FIG. 1 until it stops in the direction of the camera body, that is, in the direction of the image frame 20,
In the process, when the abutting piece 13c attached to the tip of the horizontal rod 13 begins to come into pressure contact with the abutting member 21 provided on the camera body or a fixed part of the camera and collapsing is completed,
The horizontal rod 13 reaches a position rotated counterclockwise against the torsion spring 8.

That is, when the horizontal rod 13 rotates, the lever B13b integrated therewith also rotates counterclockwise, and its right end surface, which has an arc-shaped cross section, presses the left end surface of the lever AI2. This results in gear 11 rotating clockwise.

Therefore, the clockwise rotation of the gear 11 causes the gear 10 to rotate counterclockwise against the bias of the torsion spring 8, so that the swinging member 7 is rotated counterclockwise as shown in FIG. The lens is rotated to move below the optical axis 3a and enter the space 2a within the lens barrel 2.

In other words, the conversion lens 6 and the swinging member 7 that holds it are completely retracted from the optical path of the photographing main lens 3 and stored, so that, together with the collapsing action of the lens barrel 2, the photographing The main lens 3 is brought into a state where an image is correctly focused on the film surface facing the image frame 20 of the camera body.

The main photographic lens 3 is then decomposed with the conversion lens 6 and returns to its original focal length, but in order to switch the focal length again as described above, the lens barrel 3 It is clear from the figure that simply by pulling out the lens from the camera body, the converging lens 6 is reinserted into the optical path of the main photography lens 3 by the action of the torsion spring 8, and the focal length is combined and switched. be.

As described above, according to the present invention, the conversion lens can be quickly retracted into a small space inside the lens barrel using an extremely simple device, which is extremely effective in making the camera more compact. By storing it at the bottom of the picture frame, there is no space restriction on the finder unit and the AE unit arranged at the top of the picture frame.

Furthermore, in the bifocal camera of the present invention, the conversion lens 6 and each member that operates it are arranged based on the mounting board of the shutter 4, so that the optical precision is high and the optical system is unified.・It has an advantageous structure that improves the performance and manufacturing of the camera because it can be assembled and adjusted as a unit, and all the unit parts can be housed in the camera body or a fixed part of the camera that is completely shielded from light. Therefore, there is also the advantage that the inside of the camera barrel can be simply constructed without the need to use a light shielding member or the like.

In addition, in such a bifocal camera, if there is an error in the focal length of the main photographic lens 3, measures are taken to vary the collapsing stroke in order to match the focal point on the film surface. The horizontal rod 13 is formed of an elastic member, and the horizontal rod 13 exhibits combustibility at the position where the swinging member 7 retreats from the optical axis 3a and stops, so that it can absorb the stroke of collapsing the barrel. Good.

FIG. 4 shows a general example of the bifocal camera according to the present invention, and is a perspective view of the main parts seen from the back of the camera.

〔Effect of the invention〕

According to the present invention, a compact bifocal camera is provided in which the lens barrel is made smaller and lighter, and the space above the lens barrel can be used for arranging a finder unit and an AE unit.

[Brief explanation of drawings]

1 and 4 are front and rear perspective views, respectively, of a lens barrel of a bifocal camera according to the present invention. Figures 2 and 3 are main part views of cross sections indicated by arrows AA and BB, respectively. 1. Base of lens barrel 2. ...Lens barrel 2a, ...Space 3.・・・・・・
...Main lens for photography 3a, ...Optical axis
4. ...Shutter 4a, ...Protrusion member 5. .....Shading frame 6, ....Conversion lens 7, .....Swinging member 8.1
4...Torsion spring 9,...Stop bin 10.11...Gear 13,...Rawl rod 13a...Shaft seat 13b ,...
... Lever B 13c, ... Contact piece 2
0,...Picture frame 21. ...Contact member agent Patent attorney No 1) Father-in-law Figure 3

Claims (1)

[Claims] A bifocal camera that changes the focal length of the main lens for photography by inserting and removing a conversion lens from the direction perpendicular to the imaging side optical axis of the main lens for photography inside the lens barrel. A bifocal camera characterized in that the conversion lens is inserted and removed within a lower space that includes the optical path of the main photographic lens.