JPH0289039A - Mirror structure of camera - Google Patents

Abstract

PURPOSE:To constitute the title structure so that a mirror part of a second mirror device is drawn back to the outside of a photographing optical path by forming a second mirror device for leading a luminous flux which transmits through a first mirror device to the lower face to at least two bodies and structuring them so as to be folded to the lower face side in the course of photographing. CONSTITUTION:In the camera having a fixed semitransmissive mirror 1 for dividing a photographing luminous flux in the finder direction and in the film surface direction as first mirror devices 1-5, second mirror devices 7-10 for leading a transmission light of first mirror devices 1-5 in the lower face direction are formed to at least two bodies. Also, second mirror devices 7-10 are constructed so as to be folded to the lower face at the time of photographing. In such a way, even in the case of the camera in which a first mirror device is a fixed semitransmissive mirror so that the finder can be observed even in the course of photographing, a second mirror can be drawn back to the outside of an optical path without obstructing a luminous flux.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of an eye reflex camera in which the so-called reflex mirror of the camera is formed of a fixed semi-transparent mirror.

[Conventional technology] Conventional single-lens reflex cameras employ a so-called quick return mirror, in which the mirror structure retreats out of the photographic optical path immediately before taking a picture, and immediately returns to the optical path after the photograph is completed to display the optical subject in the viewfinder. It had a structure that guided light. However, due to the above structure, the viewfinder image disappears during shooting, making it impossible to see the subject at the moment of shooting.
Particularly in sports, races, animal photography, etc. where the subject moves quickly, it is very difficult to follow the subject while continuously taking pictures, resulting in the so-called decisive moment being missed.

Therefore, conventional single-lens reflex cameras use a fixed semi-transparent mirror as the mirror that guides the light flux to the viewfinder system, and the light flux is always divided into the viewfinder system and the direction of the film surface, making it possible to constantly observe the subject through the viewfinder even during shooting. Were present.

However, in recent years, most single-lens reflex cameras have a built-in autofocus mechanism, and for this reason, the first mirror device (main mirror) for obtaining the finder light flux and the first
A second mirror device (submirror) is provided to guide the light beam that has passed through the semi-transparent part of the mirror to an autofocus detection device placed on the bottom surface of the mirror box, and the second mirror mechanism is further routed to the first mirror device. The mirror is movably supported and is swung to overlap with the first mirror device as the first mirror retreats out of the photographing optical path during photographing.

Therefore, in a semi-transparent mirror type camera in which the first mirror device is fixed as described above, the second mirror device cannot be retracted.

However, in conventional cameras, it is known that the second mirror device (submirror) is swingably supported on the film surface side of the bottom surface of the mirror box of the camera body, but in this system, the second mirror device (submirror) is Interference between the rocking trajectories of the mirror device and the second mirror device is prevented by shifting the rocking timings of both, which cannot be achieved if the first mirror device remains fixed.

In addition, in the above method, in order to swing the second mirror device while keeping the first mirror device fixed, for example, the swing fulcrum of the second mirror device is separated from the first mirror device. However, this would make the camera itself larger.

It is also conceivable to place the swinging fulcrum of the second mirror device on the photographing lens side to prevent interference with the first mirror device.
In this case, the second mirror device receives the transmitted light from the center of the first mirror device.
This means that a portion of the mirror of the mirror device cannot be retracted out of the photographing optical path.

[Means for Solving the Problems] Accordingly, in the present invention, in a camera having a fixed semi-transparent mirror as the first mirror device that divides the photographing light flux into the viewfinder direction and the film surface direction, the first mirror device By incorporating at least two second mirror devices that guide the transmitted light toward the bottom surface, and by having a structure in which the second mirror device is folded to the bottom surface during shooting, the shooting light beam is not blocked during shooting, and the viewfinder is also continuous. This provides a camera that allows observation while shooting.

[Embodiment] FIGS. 1 to 6 show cross sections of main parts of a camera according to an embodiment of the present invention.

In the figure, 1 is a semi-transparent film or glass surface, which is the first mirror that divides the light flux of the subject incident from the photographic lens into the direction of the finder system and the direction of the film surface. 2 is the first mirror that holds the first mirror 1 by adhesive. The mirror frame 3 is a first mirror holding member having a spring portion 3a that presses the first mirror frame 2 against the shaft 4 and the adjustment shaft 5. It is rotatably supported by a shaft 3b, and is attached to the main body with a screw 6. Fixed. Reference numeral 4 denotes an axis for receiving the first mirror frame 2, and although only one is shown in the figure, there are two on the left and right when the camera is viewed from the front.

Reference numeral 5 denotes an adjustment shaft that receives the first mirror frame 2 at three points along with two shafts 4, and by adjusting the amount of protrusion of this adjustment shaft 5, the angle of the first mirror can be adjusted. F is a second mirror that reflects and guides the light flux that has passed through the first mirror 1 in the direction of the distance measuring device 30; 8 is a second mirror receiving plate that holds the second mirror 7 with adhesive; 10 is a shaft; A shaft 1 rotatably supports the second mirror receiving plate 8 at 9 and is located on the photographing lens side.
1 is a second mirror driving plate rotatably supported by the camera body, and as will be explained later, a hole 10a that accommodates the second mirror 7 when the second mirror receiving plate 8 is folded;
It has a contact portion 10b that contacts the spring 12 and a shaft portion 10c that receives force from the cam portion 40a of the mirror gear 40. 12
is a coiled spring that urges the second mirror, driving plate 10, to a predetermined position when the camera is on standby, and is wound around the shaft 11 to urge the second mirror driving plate counterclockwise.

13 is a stop dowel that comes into contact with the second mirror driving plate biased by the spring 12 and positions it at a predetermined position; 14 is a dowel portion 8a of the second mirror receiving plate 8 that is supported by the camera body;
A spring 15 contacts the second mirror receiving plate 8 biased by the spring 14 and applies a biasing force to rotate the second mirror receiving plate 8 in the clockwise direction in the figure when the camera is in standby mode. A stop dowel is formed on the camera body to position it in a predetermined position. Reference numeral 16 denotes a cam portion formed on the camera body, which comes into contact with the shaft portion 8a of the second mirror receiving plate 8 when storing the mirror, which will be described later, and restricts the movement of the second mirror receiving plate 8. 17 is a spring member fixed to the camera body;
When the mirror driving plate 10 and the second mirror receiving plate 8 are folded, the shaft portion 8a of the second mirror receiving plate 8 is biased to apply an urging force for counterclockwise rotation. Reference numeral 18 denotes a group of front blades of the shutter, which covers the aperture of the camera and prevents the film 20 from being exposed to harmful light while the camera is on standby.

19 is a group of rear blades of the shutter, 20 is a photographic film, 21 is a focusing plate where the light beam from the photographing lens is focused after being reflected by the first mirror 1, and 22 is an eyepiece lens that converts the image of the focusing plate 21 into an image. The pentaprism leads to 23. 24 is a mount that removably holds the photographic lens.

FIG. 1 shows the camera in a standby state before photographing. Here, the light beam A that has passed through a photographing lens (not shown) is divided by the semi-transparent first mirror 1 into a reflected light beam B heading toward the finder and a transmitted light beam C heading toward the second mirror 7 .

The light beam B forms an image on the focusing plate 21, and the pentaprism 22
, passing through the eyepiece lens 23 and forcing the photographer to observe the subject image. The transmitted light beam C is reflected by the second mirror 7 and guided to the distance measuring device 30, where the distance to the object is calculated through predetermined processing, and a lens (not shown) is driven to perform focusing.

Next, the operation after release will be explained using FIGS. 2 to 6.

When a camera release operation is performed, a mirror down gear 40 (see FIG. 4) disposed on the camera body starts rotating counterclockwise under the force of a motor or a spring. As the rotation of the mirror down gear 40 progresses, the cam 40a of this gear 40 comes into contact with the shaft portion 10c of the second mirror drive plate 10, and the second mirror drive plate 10 is moved against the force of the spring 12 to move the shaft 11.
Start rotating clockwise around . When the second mirror drive plate 10 starts rotating clockwise (Figs. 2 and 5),
The shaft portion 8a of the second mirror receiving plate 8 comes into contact with a cam surface 16 formed on the camera body, and the second mirror receiving plate 8 starts rotating counterclockwise about the shaft 9. mirror down gear 40
As the rotation progresses further and the second mirror drive plate 10 is pushed down to a substantially horizontal position (FIGS. 3 and 6), the shaft portion 8a of the second mirror receiving plate 8 comes into contact with the spring 17, and the second The mirror receiving plate 8 is biased to rotate counterclockwise by the biasing force of the spring 17, and the second mirror driving plate 10 and the second mirror receiving plate 8 are closed so as to be almost folded (Figs. 3 and 6). ). At this time, the rotation of the mirror down gear 40 is stopped, and the second mirror driving plate 10 and the second mirror receiving plate 8 are held at the bottom of the mirror box so as to be folded over each other, and there is nothing blocking the light beam transmitted through the first mirror 1. , the transmitted light beam C reaches the shutter leading blade group 18. Next, shutter blade group 18.
19 runs at predetermined intervals, and the photographing ends. At this time, the drive plate 10 and the second mirror receiving plate 8 are connected to the focus detection device 30.
Since it is folded over and obstructing the film 20, it also serves to prevent harmful reflected light from the focus detection device from reaching the film 20 during photographing.

When the photographing is completed, the mirror down gear 40 starts rotating counterclockwise again, and the contact between the cam 40a and the shaft portion 10c is released (FIGS. 1 and 4). Second mirror drive plate 10
begins to rotate counterclockwise by the force of the spring 12, and the shaft 8a of the second mirror receiving plate also returns to the state shown in FIG. 1 while being regulated by the cam 16.

[Effects of the Invention] As described above, the present invention has a structure in which at least two second mirror devices are provided on the bottom surface for guiding the light beam transmitted through the first mirror device, and are folded to the bottom side during photographing. As a result, even in cameras where the first mirror device is a fixed semi-transparent mirror so that the finder can be observed while shooting, it is possible to move the second mirror out of the optical path without blocking the light beam. And so.

Furthermore, in this embodiment, since the second mirror device is folded over the autofocus detection device during shooting, it is possible to realize a camera that can prevent the occurrence of harmful reflected light from the autofocus detection device during shooting. Ta.

Further, although the embodiment has been described with a structure in which an autofocus detection device is disposed on the bottom surface of a mirror box, it goes without saying that a similar effect can be obtained in a camera in which a photometry arrangement for measuring the amount of light is disposed.

[Brief explanation of the drawing]

Figures 1 to 6 show a camera embodying the present invention, Figures 1 to 3 are side views explaining the camera's operation, and Figures 4 to 6.
FIG. 6 is an enlarged explanatory view of the main parts of FIGS. 1 to 3. 1/θC

Claims (2)

[Claims] (1) In a camera with a fixed first mirror that splits the light flux from the photographic lens into reflected light toward the viewfinder and transmitted light toward the film surface, the light flux is reflected toward the bottom of the first mirror. a second mirror that guides the user, a first lever that holds the second mirror, and a second lever that rotatably supports the first lever; 1. A mirror structure for a camera, characterized in that a mirror drive mechanism is provided for folding and swinging a lever of No. 2 to a position where the lever is moved out of the photographing optical path of the light beam during photographing. (2) A mirror structure for a camera according to claim (1), wherein the center of swing of the second lever is set at a position on the photographing lens side.