JPS61122634A - Single-lens reflex camera - Google Patents

Abstract

PURPOSE:To make a reflex mirror small in size, and also to raise the position accuracy of the reflex mirror by constituting a titled camera so that the reflex mirror is made to approach a photographic lens side, and also the reflex mirror can move in the in-plane direction against a mirror holder for oscillating the reflex mirror. CONSTITUTION:A reflex mirror 24 supported by a mirror holder 22 is provided in the rear of a lens board 8. This mirror holder 22 is supported so as to be freely oscillatably by a shaft 25 provided on the bottom face of a front cover 6, placed at a position where it is descended by an energizing force of a spring, when observing a finder, and moved at a photographing position at the time of photographing. The reflex mirror 24 is attached to the mirror holder 22 through a mirror frame 26. By a dovetail groove fitted of a groove formed on the mirror holder 22 and a projection formed on both sides of the mirror frame 26, the reflex mirror 24 is freely slidable in the in-plane direction against the mirror holder together with the mirror frame 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-lens reflex camera equipped with a movable reflex mirror.

[Prior art]

Various types of single-lens reflex cameras equipped with movable reflex mirrors (hereinafter simply referred to as reflex mirrors) are already known. In such an eye-reflex camera, the light beam from a reflex mirror placed tilted in the photographic optical path forms an image on the focusing glass surface, and viewfinder observation is performed by viewing this image through a finder eyepiece. By swinging and retracting from the photographing optical path, the light beam from the photographing lens is focused on the film surface.

By the way, in cameras with a large photographic screen size such as instant cameras, if the reflex mirror is brought closer to the film surface, a larger reflex mirror is required, which has many disadvantages, so it is recommended to place it on the photographing lens side. It is preferable to get closer. However, as mentioned above, the reflex mirror retreats from the photographing optical path while swinging, so if the reflex mirror is brought too close to the photographing lens side, when the reflex mirror swings, its tip may touch the photographic lens or the lens board that holds it. It starts to interfere. In addition, to avoid this situation, it is necessary to simply shorten the length of the reflex mirror. (If this happens, a part of the light beam that passes through the photographic lens will be eclipsed by the reflex mirror, so-called mirror breakage will occur, so it is necessary to make the reflex mirror more compact.) This results in restrictions.

In consideration of these circumstances, there is a known configuration in which the swing axis of the reflex mirror is made movable, and when the reflex mirror is rocked, the reflex mirror is rocked while moving the swing axis in a direction away from the photographic lens. There is. but,
Such conventional devices have disadvantages in that they have a complicated structure, are difficult to maintain the positional accuracy of the reflex mirror, and are difficult to assemble.

[Object of the Invention] The present invention has been made in view of the above-mentioned technical background.It is an object of the present invention to reduce the size of a swinging reflex mirror used in an eye reflex camera and to improve the movement mechanism of the reflex mirror. To provide a single-lens reflex camera which is free from interference between the tip of a reflex mirror and a photographic lens and from breakage of the mirror, and which can maintain positional accuracy of the reflex mirror.

[Structure of the invention]

In order to achieve the above object, in the present invention, in order to reduce the size of the reflex mirror, the reflex mirror is brought closer to the photographic lens side, and the reflex mirror is moved in the in-plane direction relative to the mirror holder that swings the reflex mirror. It is designed so that it can be moved to.

[Configuration of Example]

A first example showing an example of an instant camera to which the present invention is applied
In the figure, a film pack 1 containing a known mono-sheet type instant film unit 4 is housed in a camera body 2 in a light-shielded state. A finder eyepiece 3 is attached to the top of the camera body 2. A front cover 6 is rotatably attached to the camera body 2 via a fixed shaft 5, and a lens board 8. A mirror cover 9 is pivoted.

The lens board 8 includes a photographing lens 10. shutter 1
1, and a magnification conversion lens 12 is attached.

The photographing lens 10 is movable on the photographing optical axis 15 by a well-known helicoid mechanism or the like, and the magnification conversion lens 12 is moved along the photographing optical path 2 by a moving mechanism 13.
It is movable between a position within 0 and a position retracted from the photographing optical path 20.

It is said that This moving mechanism 13 is configured as shown in FIG. 2, for example, and a lens holder 16 to which the magnification conversion lens 12 is fixed is pivoted to a shaft 17 implanted in the lens board 8. , the magnification conversion lens 12 is retracted from the photographing optical path 20 by driving the solenoid 40.

The drive of the solenoid 40 is controlled by a microswitch 45 that detects the operation of a mirror drive lever 18, which will be described later, and a drive circuit 46 that is operated in response to a signal from the microswitch 45.

A reflex mirror 24 supported by a mirror bracket 22 is provided behind the lens board 8. This mirror holder 22 is swingably supported by a shaft 25 provided on the bottom surface of the front cover 6, and is placed in a lowered position by the urging force of a spring 23 (see FIG. 2) when observing through the finder. When photographing, the camera is moved to the photographing position indicated by the two-dot chain line in the figure. The reflex mirror 24 is attached to the mirror holder 22 via a mirror frame 26.

By dovetail fitting between the groove 27 formed in the mirror holder 22 and the protrusions 28 formed on both sides of the mirror frame 26, the reflex mirror 24, together with the mirror and the frame 26, is attached to the mirror holder 22 within its plane. It can be slid in any direction. Note that, as shown in FIG. 2, the mirror holder 22 has a pin 21 implanted in its side surface, and by pushing up this pin 21 with the mirror drive lever 18, the mirror holder 22 resists the spring 23. and is shaken.

Further, the mirror drive lever 18 is operated by a conventionally known mirror drive mechanism 19 immediately before photographing is performed.

A focusing glass 30 made of, for example, a Fresnel plate is fixed to the lower surface of the front cover 6, and when observing through the finder, the photographing lens 10, the magnification conversion lens 12,
A photographic screen is then imaged through the reflex mirror 24.

This focusing glass 30 is installed close to the reflex mirror 24, and the optical path length from the reflex mirror 24 is
4 and the film unit 4.

The lower surface of the front cover 6 is further provided with two parts via a shaft 31.
A book regulating lever 32 is pivotally mounted, and its tip is pivotally supported on both sides of the mirror frame 26.

Therefore, when the mirror holder 22 swings clockwise in FIG. 1, the reflex mirror 24 is slid upward into the mirror holder 22 due to the link action of the regulating lever 32.

Note that the clockwise rotation of the restriction lever 32 is restricted by a stopper 33.

The photographic screen imaged on the focusing glass 30 is observed with the eyepiece 3 via a finder mirror 35 fixed to the mirror cover 9 and an auxiliary lens 36. The auxiliary lens 36 is supported by the front cover 6 so as to be freely foldable, and is folded into the front cover 6 when the camera is folded. In addition,
The front cover 6 can be folded along the front surface of the camera body 2 via the shaft 5, and the lens board 8,
Each of the mirror covers 9 can also be folded along the front cover 6 via the shaft 7. Note that reference numeral 42 indicates a bellows provided at a required portion to keep the inside of the dark box in a light-shielding state.

Further, as already mentioned, the shutter 11 for controlling the amount of exposure to the film unit 4 is connected to the lens board 8.
It is located inside. Therefore, in order to enable viewfinder observation, it is necessary to keep the shutter 11 open and allow photographing light to enter the reflex mirror 24. At this time, the reflex mirror 24. mirror frame 26,
Alternatively, if light leaks from the periphery of the mirror holder 22 to the film unit side, fog will occur on the film unit 4, so the mirror holder 22. A light-shielding side 43 is in close contact with the back side of the mirror frame 26.

Note that when a shutter button (not shown) is operated to take a photograph, the shutter 11 is first closed, and then the reflex mirror 24 and the magnification conversion lens 12 are retracted from the photographing optical path. Then, the shutter 11 opens again to expose the film unit, and closes after a predetermined exposure time.

Thereafter, the magnification conversion lens 12 and the reflex mirror 24 return to the illustrated positions, and the shutter 11 is opened.

[Effect of the embodiment]

The operation of the single-lens reflex camera with the above-described configuration is as follows. First, the front cover 6, lens board 8,
Then, the mirror cover 9 is raised to the operating condition shown in FIG. 1 and locked. In this state, the mirror holder 22 is urged by the spring 23 toward the lowered position shown in FIG. As a result, the regulation lever 32
is biased clockwise around the shaft 31, and the mirror frame 2
6 is slid downward on the mirror holder 22.

When the regulation lever 32 comes into contact with the stopper 33, the mirror holder 22. The initial positions of the mirror frame 26 and the reflex mirror 24, that is, the finder observation position are set. In this way, the reflex mirror 24
By performing this positioning, vibrations are less likely to occur when positioning the reflex mirror 24 at the observation position, and positioning accuracy can be improved.

In this finder observation state, the shutter 11 is in an open state, and the magnification conversion lens 12 is also inserted into the photographing optical path. Therefore, the photographing light that has passed through the photographic lens 10 is converged by the magnification conversion lens 12 and formed into an image on the focusing glass 30, which is arranged with an optical path length shorter than the optical path length up to the film unit 4. This image is shown in the finder mirror 35. It will be observed by the eyepiece 3 through the auxiliary lens 36.

After performing the framing in this manner, when the shutter button is operated, the shutter 11 is first closed. and,
The mirror drive lever 18 is activated by the operation of the mirror drive mechanism 19.
(Fig. 2) is swung clockwise. As the mirror drive lever 18 swings, the mirror holder 22 rises about the shaft 25 against the spring 23. At the same time, the mirror frame 26 is guided by the dovetail groove fitting portion and slid above the mirror holder 22 via the link connection by the regulation lever 32. Therefore, the length between the lower end of the mirror frame 26 and the shaft 25 becomes shorter as the mirror holder 22 swings, so even if the reflex mirror 24 is brought close to the lens board 8 side, the lower end is There is no collision with the lens 12 or the back of the lens board 8. Note that the tip of the mirror holder 22 comes into close contact with the stopper 37, and the clockwise urging force remains applied to the mirror drive lever 18, so that the mirror holder 22 is held at the photographing position shown by the two-dot chain line. Ru. Further, in order to prevent fogging on the film unit 4 due to incident light from the viewfinder unpiece 3 side during the raising process of the mirror holder 22, an eyepiece shutter is provided and closed at a predetermined timing. is preferred.

An electrical signal obtained from the microswitch 45 at the time when the mirror drive lever 18 starts swinging is input to the drive circuit 46. The drive circuit 46 drives the solenoid 40 after the time period until the mirror holder 22 is swung to the photographing position has elapsed. As a result, the magnification conversion lens 1
2 is moved to the position shown by the two-dot chain line in FIG.

Thereafter, the shutter 11 is activated by a known automatic exposure control device (
(not shown) is opened for a predetermined time to expose the film unit. At this time, as described above, since the magnification conversion lens 12 is not used, the subject image is formed on the film unit only by the photographic lens 10. During this time, the mirror drive lever 18 is held in the raised position.

When the shutter 11 closes and the exposure ends, the exposed film unit is sent out of the film bag 1 by a known scraping device in response to the end signal, and is pressed by a developing roller 50 (see FIG. 1). While
It is ejected from the camera body 2.

Further, the operation of the drive circuit 46 is stopped by the termination signal. Therefore, the lens holder 16 rotates clockwise around the shaft 17 due to the biasing force of the return spring built into the solenoid 40, and comes into contact with the stopper 48 and stops. As a result, the magnification conversion lens 12
He will be returned within. Thereafter, when the operation of the mirror drive mechanism 19 is completed, the biasing force that biases the mirror drive lever 18 to the raised position is released, so that the mirror holder 22 is moved together with the mirror drive lever 18 by the biasing force of the spring 23. It descends towards the position. Therefore, the regulation lever 32 swings clockwise about the shaft 31, and the mirror frame 26 is slid downward along the mirror holder 22 while being guided by the dovetail groove fitting.゛And, by restricting the clockwise swinging of the restriction lever 32 by the stopper 33, the mirror holder 2
The 2° mirror frame 26 and the reflex mirror 24 all return to their initial positions. In this way, the light-shielding side 43 comes into close contact with the rear side periphery of the mirror holder 22° mirror frame 26, and after the film pack 1 side is in a light-shielded state, the shutter 11 is opened.
This returns the camera to a standby state for the next photograph.

Although the explanation has been made in accordance with the illustrated embodiment, various types of drive mechanisms and interlocking mechanisms can be used to drive the mirror holder 22, including manual ones, for example. Further, as is commonly used in conventional single-lens reflex cameras, it is desirable that the stopper 37 that stops the mirror holder 22 at the photographing position or the stopper 33 that stops the mirror holder 22 at the observation position have a bounce prevention function. Note that in carrying out the present invention, the magnification conversion lens 12 is not necessarily used (
But that's fine. Furthermore, although the present invention is particularly effective when used in cameras with large screen sizes, such as the above-mentioned instant cameras, it is, of course, equally applicable to ordinary 35 mm cameras.

〔Effect of the invention〕

As mentioned above, in the single-lens reflex camera of the present invention,
Even if the reflex mirror is moved closer to the photographing lens side in order to make the reflex mirror more compact, when the reflex mirror swings, it also slides in the in-plane direction, so the reflex mirror swings while its tip is retracted. Therefore, mirror breakage at the observation position is eliminated, and at the same time, interference between the tip of the reflex mirror and the photographing lens is also prevented. Furthermore, since the reflex mirror is designed to slide in the in-plane direction, the positional accuracy of the reflex mirror can be maintained reliably, and the structure does not become complicated.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention. FIG. 2 is a perspective view of essential parts showing an example of a reflex mirror moving mechanism used in the present invention. 2...Camera body 6...Front cover 8...
・Lens board 10・・Photographing lens 12・・Magnification conversion lens 16・・Lens holder 22・・Mirror holder 24・・
Reflex mirror 26...Mirror frame 30...Focusing glass 32...Regulation lever 35...Finder mirror. 40... Solenoid. pole

Claims (2)

[Claims] (1) A single lens that has a reflex mirror that is placed between the photographic lens and the film surface and is movable between the observation position where the photographic optical path is deflected to the focusing glass and the photographic position where it swings out of the photographic optical path and retreats. The reflex camera is characterized by comprising a mirror holder which holds the reflex mirror movably in its in-plane direction and swings the reflex mirror to the photographing position while moving in the in-plane direction during photographing. A single-lens reflex camera. (2) The single-lens reflex camera according to claim 1, wherein the reflex mirror is movably held in a mirror holder by dovetail fitting.