JPH0121293Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The invention is an Albada type winder.
The present invention relates to an Albada type viewfinder in which the photographing angle of view in a camera capable of switching to a plurality of focal lengths is changed by changing the light frame within the viewfinder.

[Prior Art] In a camera capable of switching to a plurality of focal lengths, if the photographing optical system and the finder optical system are different, it is necessary to switch the finder optical system in response to the conversion of the photographing optical system. Conventionally, two methods have been known: one is to switch the viewfinder optical system itself, and the other is a method to change the optical frame within the viewfinder. In the latter case, several methods have already been proposed and implemented that use a lighting system. There is. However, there is no means to implement this method in the Albada type finder.

[Problems to be solved by the invention] Conventionally, the angle of view of the Albada type viewfinder could only be changed by changing the optical system in response to changing the focal length of the photographic lens. The problem with this method is that its structure is complex and extremely large.

The present invention has been made to solve these problems, and the object is to provide an Albada type finder in which the light frame can be easily switched even in the Albada type finder.

[Means and effects for solving the problems] The Albada type viewfinder according to the present invention is applicable to a camera in which the photographing lens can be switched between a first and second focal length, and the Albada type viewfinder eyepiece , a first luminous part for creating a light frame corresponding to the angle of view of the first focal length provided on the surface facing the half mirror; an index plate having a through hole or a transparent part that guides the subject light to the eyepiece and a second luminous part that creates a light frame corresponding to the angle of view of the second focal length; and, in response to switching of the photographing lens from the first focal length to the second focal length, the index plate is moved from a retracted position that does not interfere with the luminous flux of the viewfinder optical system to cover the first bright part, and The present invention is characterized by comprising a rotating member that rotates the second bright portion to a position where it appears on the half mirror side.

[Example] Hereinafter, the present invention will be explained based on the illustrated example.

FIG. 1 is a schematic diagram showing the structure of an Albada type finder showing an embodiment of the present invention. is a half mirror, and the lens 3 is an eyepiece lens, and its front surface 3a has a bright part 3b (fifth lens) that creates a light frame corresponding to the angle of view of the first focal length of the camera.
(see figure).

As shown in FIGS. 1 and 2, the indicator plate 4 as a means for switching the light frame in the Albada type finder of the present invention has a horizontally long guide groove 9 provided on the inner surface facing the finder frame (not shown). It is constructed integrally with a support member 5 that rotates around a support shaft 6 whose both ends are slidably supported inside, and rotates approximately 90 degrees around the support shaft 6 as a width center axis. It's summery. One end of the torsion spring 7 wound around the support shaft 6 is hung on a spring hooking protrusion 8 provided on the inner wall of the winder frame, and the other end is hooked on a spring hooking protrusion 16 provided on the side wall of the support member 5. It is being Therefore, index plate 4
is, via the integrated support member 5,
With the support shaft 6 as the central axis, move clockwise in FIG.
It is biased in the direction of contacting a. Both ends of the support shaft 6 are supported by the guide groove 9, and its sliding range is regulated by both ends of the guide groove 9. Furthermore, the index plate 4 is
In order to reduce the diopter difference between the distance measuring frame, which does not change even after the actual field of view and focal length conversion, and the newly appearing light frame, the thinner the better, the thinner the lens, the better. In order to prevent the bright part 3b for the light frame from peeling off on the surface 3a, at least one protrusion 4c (four in this case) is provided in a portion outside the actual field of view that does not hit the bright part 3b. The adhesion of the index plate 4 to the eyepiece surface 3a is extremely important, and for this reason, as described above, the support shaft 6 is made slidable, which allows the index plate 4 to rotate when the index plate 4 rotates. It is designed to prevent galling, etc. The index plate 4 is made of an opaque thin plate, and in the center thereof,
As shown in Figures 2 and 4, a square hole A is provided that is large enough to accommodate the actual field of view when the photographic optical system is in telephoto mode, and the periphery of the square hole A is bright enough to create a light frame during telephoto mode. A portion 4b is provided.

As shown in FIG. 1, the operating lever 12 that rotates the indicator plate 4 has guide pins 13a and 13b implanted in the finder frame inserted into two guide grooves 12b and 12b that are arranged in series in the longitudinal direction. As a result, the movement is restricted, and the movement is performed by moving the drive member 10 in the direction of the arrow.
That is, when the photographic optical system is wide (wide-angle), the driving member 10 and the operating lever 12 are in the state shown in FIG. It is pushed by the upper surface of the right end, rotates almost horizontally against the elasticity of the torsion spring 7, and retreats from the optical path of the finder. At this time, the position of the drive member 10 will vary in the direction of the arrow due to focusing adjustment, etc., so the shape of the contact surface between the operating lever 12 and the support member 5 needs to be extremely resistant to this. In this embodiment, the upper end surface 12a of the operating lever 12 supports the lower end surface of the support member 5.

In this way, when the photographic optical system is wide, the index plate 4 is retracted from the viewfinder optical path, and the index plate 4 is placed within the viewfinder field of view as well as the actual field of view and the front surface 3a of the eyepiece lens 3 as shown in FIGS. 8 and 5. The illuminated portion 3b is reflected by the half mirror on the rear surface 2a of the lens 2, and a light frame 3b as a so-called bright frame is clearly seen overlapping the subject image as shown in FIG.

Next, when the photographic optical system is telephoto, it works as follows. That is, when the operating lever 12 in the state shown in FIG. 1 is moved leftward by the drive member 10 to the state shown in FIG. move,
The indicator plate 4 comes into contact with the front surface of the eyepiece lens 3 and stops. At this time, the protrusion 4c of the index plate 4 may cause the abutment surface of the index plate 4 to come into contact with the bright part 3b on the front surface 3a of the eyepiece 3 and damage the bright part 3b, or may cause damage to the bright part 3b during solid contact. This prevents the bright part 3b from peeling off, etc. Note that the protrusion 4c may be provided in a portion of the front surface 3a of the eyepiece 3 that is not included in the actual field of view.

In this way, when the index plate 4 is in the state shown in FIG. 3, the actual field of view can be seen in the same field of view as in the wide-angle mode due to the light rays entering from the square hole A (see FIG. 4). As shown in FIG. 9, this time, instead of the bright part 3b of the eyepiece lens 3, the bright part 4b of the index plate 4 is replaced by the half mirror 2 of the lens 2.
As shown in FIG. 7, it can be clearly seen as a light frame 4b in telephoto mode. At this time, the bright portion 3b of the eyepiece lens 3 is hidden by the indicator plate 4 and cannot be seen. In other words, the viewfinder light frame can be extremely easily switched between wide and telephoto by simply rotating the index plate 4 approximately 90 degrees between the state shown in FIG. 1 and the state shown in FIG.

Further, the luminous portion 4 is provided on the front surface 4a of the index plate 4.
In addition to providing a mark ``b'', as shown in FIG. 4, a sign such as "TELE" indicating that the camera is in tele mode may be provided so as to easily distinguish between wide and tele mode.

In addition, in order to minimize the diopter difference with the eyepiece lens surface 3a, the index plate 4 uses a transparent plate 21 as shown in FIG. 10 instead of an opaque thin plate.
A bright part 21a corresponding to the bright part 4b is provided on the surface in contact with the eyepiece surface 3a, and further above that,
It is also possible to print black on the part outside the field of view during telephoto mode. In this way, the performance of the index plate 21 can be further improved. In the embodiments described above, the indicator plate is made separate from the support member, but it goes without saying that these may be formed as one piece by molding or the like.

[Effects of the invention] As explained above, according to the invention, the angle of view of the conventional Albada type viewfinder could only be changed by switching the optical system, but it can be done by using the light frame with an extremely simple structure. It is possible to provide an Albada type finder which can be switched by switching and which can be extremely easily performed in conjunction with the conversion of the focal length of the photographing lens.

[Brief explanation of the drawing]

FIG. 1 is a side view of an Albada type finder showing an embodiment of the present invention, FIG. 2 is a perspective view of the index plate of the finder shown in FIG. 1, and FIG.
Fig. 4 is a front view of the main part of the indicator plate in Fig. 2;
The figures are front views showing a state in which a light frame corresponding to the angle of view of the first focal length is formed within the viewfinder field of view, and Fig. 7 is a front view showing a state in which a light frame corresponding to the angle of view of the second focal length is formed within the viewfinder field of view. FIGS. 8 and 9 are front views showing the state in which the window is formed, and FIGS.
This figure is a perspective view showing another example of the index plate shown in FIG. 2 above. 3...Finder eyepiece, 3b...Luminous part, 4...Index plate, 4b...Luminous part, 4c...Protrusion part.

Claims (1)

[Claims for Utility Model Registration] (1) In an Albada-type viewfinder in a camera in which the photographing lens can be switched between a first and a second focal length, a first luminous part that creates a light frame corresponding to the angle of view of the first focal length; and a transparent hole part that guides object light in a field of view corresponding to the angle of view of the second focal length to the eyepiece. or an index plate having a transparent part and a second luminous part that creates a light frame corresponding to the angle of view of the second focal length; In response to switching from the distance to the second focal length, the index plate is moved from a retracted position that does not interfere with the luminous flux of the viewfinder optical system to cover the first bright part, and the second bright part is moved to the side of the half mirror. An Albada-type finder characterized by comprising: a rotating member that is rotated to a position where it is exposed; (2) The Albada type finder according to claim 1, wherein a protrusion is provided at at least one location on the index plate or the opposing surface of the eyepiece. (3) The Albada type viewfinder according to claim 1, wherein the indicator plate is a transparent plate, and a luminous part is provided on the side surface of the indicator plate that abuts the eyepiece.