JPS5928415Y2 - Pentaprism fixing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a pentaprism fixing device for a single-lens reflex camera.

In a conventional pentaprism fixing device, as shown in FIG. 1, a pentaprism 1 and a prism frame 2 are
The pentagonal prism is pressed by connecting them with a spring 6 via a pentagonal holding plate 5, and a screw 3 implanted in the prism frame for left-right adjustment is brought into contact with the side surface 1b of the pentagonal prism.

Further, the space created between the roof surface 1a of the pentagonal prism 1 and the top plate 4 is wasted by using conventional pentagonal prism fixing devices such as the pentagonal holding plate 5 and the spring 6.

However, as cameras become smaller, it is no exaggeration to say that the key to miniaturization is how effectively the space is used to store electronic circuit boards and the like.

Furthermore, it is well known that electronic circuit boards and the like are usually fixed by pasting them on the roof surface, which is the inclined surface of the pentaprism 19, and most current single-lens reflex cameras do not use this method. ing.

In such a case, as in the conventional example described above, the pentaprism 1
If a penta presser plate 5 and a spring 6 are separately provided to fix the pentameter, an extremely undesirable situation may occur in which the fixing member comes into contact with an electronic circuit board or the like, causing a short circuit or a leak.

In other words, a camera's electronic circuit board normally uses a very small amount of current to control automatic exposure and metering circuits, and even the slightest leak of current can be fatal to the camera.
cormorant.

Also, patent No. 30923 and patent No. 31258 for binoculars.
Each specification of the No. 1 issue discloses a so-called right-angle prism that uses an inclined surface to fix the prism and adjust its position, but the binoculars used in these binoculars are right-angle prisms. The shape of the pentaprism is different from that of the pentaprism, and their purpose is to hold down the pentaprism in a downward direction by using the inclined surface of the rectangular prism. The aim is to simultaneously press down not only in the direction but also in the forward direction.

In view of the above-mentioned facts, and in order to improve the above-mentioned drawbacks, the present invention proposes a pentaprism fixing device having a simple structure and a small number of parts.

An embodiment of the present invention will be described below with reference to the same cylinder.

In FIG. 2, 1 is a pentaprism, 2 is a prism frame, and protrusions are provided near the center of both side surfaces of the prism frame 2 to cover the lower part of the roof surface 1a of the prism 1. The portion is provided with a threaded portion.

Reference numeral 3 denotes a screw, which is implanted in the screw portion so as to be freely removable and removable, and its tip abuts against the roof surface 1a.

This screw 3 serves to fix the pentaprism and to adjust the left and right sides of the pentaprism.

4 is the upper front plate. One end of the screw 3 is in contact with the roof surface 1a of the pentagonal prism 1, and the other end is provided with a slot for adjustment.

1. To adjust the left and right sides of the pentaprism 1, loosen the screws on both sides of the prism frame 2, and after confirming the predetermined position of the pentaprism 1, tighten the screws 1 at 1, where one screw 3 contacts the roof surface, and tighten the screws on the other side. Tighten screw 3.

Since the fine adjustment is a screw, it can be made quite finely.

After the left and right adjustment, since the walking surface of the pentagonal prism 1 is inclined by the screw 3, a downward force is applied.
Fixation of the pentaprism is also completed by pressing the pentaprism.

That is, in the conventional example described above, the bottom surface and the rear surface (exit surface) of the pentaprism were fixed against the prism frame by a spring, and screws for left and right adjustment were further provided.

The present invention fixes two surfaces of the pentaprism, that is, the bottom surface and in this case the front surface, by applying force to the prism frame using only the screws that come into contact with the roof surface of the pentaprism, and at the same time enables left and right adjustment.

As described above, in the present invention, from both sides of the prism frame 2,
By holding down the roof surface 1a of the pentaprism 1 with the screws 3, it is possible to perform both left and right adjustment and fixing, and it is simple and can be constructed with a small number of parts.Assembly and adjustment are also easy, and the roof surface and upper front plate This not only makes effective use of the space between the pentaprism and the miniaturization of the camera, but also greatly reduces problems such as short circuits and leaks to electronic circuit boards, etc. that are attached to the roof surface of the pentaprism. , provides a highly effective and practical pentaprism fixation device.

[Brief explanation of drawings]

FIG. 1 is a front and side view of an embodiment of a conventional pentaprism fixing device, and FIG. 2 is a front and side view of an embodiment of the present invention. 1: Pentaprism, 1a: Roof surface, 2 Nibrism frame,
3: Screw, 4: Upper front plate, 5: Penta presser plate, 6: Spring.

Claims (1)

[Scope of utility model registration request] In the viewfinder of a single-lens reflex camera, which consists of an optical system mainly composed of a pentaprism and a prism frame that holds the optical system, the lower part of the roof opening 1a of the prism 1 is covered on both sides of the central part of the prism frame 2. A pentaprism characterized in that a screw 3 is provided in the protrusion so as to be able to move in and out of the protrusion and abut the roof surface 1a, and the downward component force of the roof surface 1a is used for fixing and horizontal adjustment. fixation device.