JPH0559436U - Single-lens reflex camera viewfinder device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a finder device capable of preventing a problem such as a pentamirror or a pentaprism inserted in a pentaholder rising due to burrs. [Pattern] A pentamirror or pentaprism; a pentaholder formed of a molded product of a synthetic resin material having a pentareceptive surface on which the pentamirror or pentaprism is mounted; The penta holder is a single-lens reflex camera in which the parting line of the molding die is located on the penta receiving surface and the rear end of the field frame is located in front of this parting line. In the finder device of the camera, a lower portion located behind the parting line is formed on the penta receiving surface of the penta holder.

Description

[Detailed description of the device]

[0001]

【Technical field】

 The present invention relates to a viewfinder device for a single-lens reflex camera, and more particularly to a viewfinder device for a single-lens reflex camera in which a pentamirror or a pentaprism is not lifted up by a burr that tends to be formed on a parting line.

[0002]

[Prior art and its problems]

 Conventionally, the viewfinder device of a single-lens reflex camera forms an image of a subject, which is transmitted through a taking lens and reflected by a quick return mirror (first mirror), on a focusing plate 1 as shown in FIG. It is reflected by the roof surface 3 on the upper side of the pentagonal roof prism 2 and the third reflecting surface 4 on the front side and then guided to the loupe lens (eyepiece) 36 to obtain a subject image without vertical and horizontal inversion.

However, the finder device using this pentaprism has a problem that the processing cost of the prism is high and heavy. Therefore, a cavity-type pentamirror has been proposed in which only the portions corresponding to the roof surface 3 and the third reflecting surface 4 of the pentaprism are used as reflecting mirrors. This hollow pentamirror has the advantages that it is lightweight and the manufacturing cost is low because the glass part of the pentaprism is hollow.

This hollow pentamirror is fixed to a camera body (not shown) via a mirror holder (pentaholder). An example thereof is shown in FIGS. The cavity-type pentamirror 10 has a roof surface 11 on the left and right of the upper part of the inner surface thereof and a third reflecting surface 12 on the front side thereof. The hollow pentamirror 10 is externally configured such that the left and right side surfaces 13 and the rear surface 14a are substantially vertical surfaces, and the third reflecting surface 12 is inclined so as to project forward as it goes upward. Formed as surface 15. The rear surface 14a integrally has a protruding portion 14b which is protruded rearward by the thickness of the rear side surface 24 of the mirror holder 20 and which is to be inserted into the insertion opening 20b of the rear side surface 24. The third reflecting surface 12 has a mirror surface formed by vapor deposition in the range indicated by A in FIG.

On the other hand, the mirror holder 20 has a concave portion 21 into which the lower part of the hollow penta mirror 10 is inserted, and a plurality of flanges 22 for fixing to the camera body. Each of these flanges 22 has a fixing screw hole. 22a is provided. The recess 21 is composed of left and right inner side surfaces 23, a rear side surface 24, and an inclined surface 25, which correspond to the side surface 13, the back surface 14 and the inclined surface 15 of the hollow pentamirror 10. At the bottom of the recess 21, an inner peripheral flange-shaped mirror receiving portion (penta receiving surface) 9 is formed on which the bottom surface of the hollow penta mirror 10 is placed to determine the insertion depth. The mirror receiving portion 9 includes a mirror mounting surface 26d on which the bottom surface of the hollow penta mirror 10 is directly mounted, and an inner peripheral side (front) of the mirror mounting surface 26d. It has a video frame mounting portion 26c, which is formed lower than 26d, for housing and mounting the video frame 62.

The mirror holder 20 further corresponds to a magnifying lens (not shown) fixed to the camera body side, and has the insertion opening 20b into which the protruding portion 14b of the hollow penta mirror 10 is inserted and the photographing lens. It has an opening 20c for guiding the light beam to the loupe lens. The mirror holder 20 has a lens mounting portion 59 for mounting a photometric lens (not shown) above the insertion opening 20b. Lens rear support protrusions 60 are formed on the left and right of the lens mounting portion 59, and lens front support protrusions 44 are formed in front of the left and right lens rear support protrusions 60, respectively. A fitting support groove 45 for fitting and supporting the left and right protruding support pieces of the photometric lens is formed between the lens front support projection 44 and the lens rear support projection 60.

The assembling work of the finder device having such a configuration is performed as follows. First, the photometric lens is fitted and supported in the fitting support groove 45 of the mirror holder 20. Then, a video frame (visual field frame) 62 made of a thin synthetic resin material or the like is mounted on the video frame mounting portion 26c at the bottom of the mirror holder 20, and the cavity type pentamirror 10 is inserted into the concave portion 21. The outer peripheral side (rear side) of the bottom surface of the mirror 10 is mounted on the mirror mounting surface 26d and the inner peripheral side (front side) of the bottom surface is mounted on the image frame 62, and the hollow pentamirror 10 is coupled to the mirror holder 20.

By the way, the mirror holder 20 having such a structure is manufactured by injection molding using a molding die in which an upper die, a lower die and the like are combined, but the insertion opening 20 b is formed in the rear side surface 24. Due to the presence of the wall thickness a of the rear side surface 24, it is rational to easily configure the mold because one of the plurality of parting lines is set with the rear side surface 24 as a reference. Is. Therefore, when the rear side surface 24 is extended downward, the position where it comes into contact with the mirror receiving portion 9 is the parting line. In fact, in the mirror holder 20, the parting line is aligned with the boundary line between the image frame mounting portion 26c and the mirror mounting surface 26d.

For this reason, a burr 63 (FIG. 7) due to a partition line is likely to occur at the boundary between the image frame mounting portion 26c and the mirror mounting surface 26d, and the presence of this burr 63 causes the mirror mounting surface 26d. The bottom surface of the pentamirror 10, which should be in close contact with, may float up. In this case, the distance D between the focusing plate 1 and the roof surface 11 is deviated, the optical axis O is displaced, and the accuracy is impaired. Further, the pentamirror 10 cannot be brought into close contact with the finder device. And the like. It should be noted that d in FIG. 7 represents a constant distance from the roof surface 11 to the bottom surface of the pentamirror 10.

[0010]

[The purpose of the device]

 An object of the present invention is to provide a finder device that can prevent problems such as a pentamirror or a pentaprism inserted in a pentaholder being lifted by burrs, based on the above-mentioned awareness.

[0011]

[Outline of the device]

 The present invention provides a pentamirror or a pentaprism; a penholder made of a synthetic resin material having a pentad receiving surface for mounting the pentamirror or the pentaprism; a lower surface of the pentamirror or the pentaprism and a pentaholder. The penta holder has a field frame located between the penta frame and the penta frame, and the penta holder has a parting line of a molding die located on the penta frame and a rear end of the field frame is in front of the part line. In the viewfinder device of the single-lens reflex camera located at, the lower part located behind the pentading surface of the penta holder is defined on the penta receiving surface of the penta holder.

[0012]

[Example of device]

 The present invention will be described below with reference to the illustrated embodiments. 1 to 3 show an embodiment of a finder device according to the present invention. FIG. 1 is a vertical cross-sectional view of the finder device, FIG. 2 is a partially enlarged view showing a main part of FIG. 1, and FIG. It is a disassembled perspective view which shows the whole finder apparatus. The same parts as those of the finder device which is the basis of the present invention shown in FIGS. 4 to 9 are designated by the same reference numerals and the description thereof will be omitted.

The cavity type pentamirror 10 of the present embodiment leaves a rear surface (right side in the drawing) of the bottom surface as a convex wall portion 65 a, and is provided between the bottom surface of the convex wall portion 65 a and the roof surface 11. The distance is configured to be the same as the distance d shown in FIG. 7. In front of the convex wall portion 65a (on the left side in the figure), an abutting surface 65b is formed by notching upward by a predetermined distance b. The boundary between the contact surface 65b and the convex wall 65a is substantially aligned with the parting line formed by the molding die during manufacturing.

The mirror receiving portion 9 of the mirror holder 20 has a mounting surface 26b on the front side of the parting line and a recess (lower portion) 26a on the rear side thereof which is lower than the mounting surface 26b by a predetermined amount. Has been done. The mounting surface 26b projects toward the contact surface 65b, and is configured so that the same distance D as in FIG. 7 can be maintained with the image frame 62 held between the mounting surface 26b and the contact surface 65b. ing. As a result, the image frame 62, which was positioned on the same plane as the bottom surface of the cavity type pentamirror 10 in FIG. 7, that is, the mirror mounting surface 26d, is raised to the position of the bottom surface of the convex wall portion 65a in this embodiment. Are arranged. That is, the video frame 62 is located above the distance of FIG. 7 by the distance b. The concave portion 26a has a depth sufficient to accommodate the convex wall portion 65a that is inserted while the image frame 62 is sandwiched between the placing surface 26b.

On the other hand, since the image frame 62 mounted on the mounting surface 26b is configured to be raised to the pentamirror 10 side by the distance b 1, the convex wall of the bottom surface of the hollow pentamirror 10 is formed. The portion other than the portion 65a, that is, the side surface 13 and the inclined surface 15 are formed to be shorter by the distance b than that shown in FIG.

Therefore, when assembling the finder apparatus of this embodiment, first, the image frame 62 is inserted into the recess 21 of the mirror holder 20 in which the photometric lens is inserted into the lens mounting portion 59, and is placed on the placement surface 26b. Keep it. In this case, the rear end of the image frame 62 is substantially aligned with the parting line, that is, the boundary between the mounting surface 26b and the recess 26a. Then, when the hollow pentamirror 10 is inserted into the concave portion 21 and the bottom surface thereof is brought into contact with the mirror receiving portion 9, the contact surface 65b of the pentamirror 10 and the mounting surface 26b form the rear end of the image frame 62. The convex wall portion 65a is completely inserted (engaged) in the concave portion 26a while holding the portion. The cavity pentamirror 10 is properly positioned on the mirror holder 20 by the engagement of the convex wall portion 65a with the concave portion 26a. At this time, even if there is a burr at the boundary between the mounting surface 26b, which is a parting line, and the recess 26a, this burr is absorbed by the thickness of the image frame 62, so that the contact surface 65b. Can properly contact the rear end of the image frame 62 without being affected by burrs, and thus the hollow pentamirror 10 does not float up. As a result, the distance D between the focusing plate 1 and the roof surface 11 is prevented from being misaligned, and the optical axis O is certainly prevented from being inconvenient. .. The focus plate 1 is mounted below the mirror holder 20 via a focus plate pressing member 64.

As described above, since the relative position of the image frame 62 in the finder device is higher than that described with reference to FIG. 7, the distance c between the image frame 62 and the focus plate 1 is reduced. Since the space between the image frame 62 and the focus plate 1 is larger than the distance c ′ in FIG. 7, the display device in the viewfinder (not shown) inserted in this space should be rather large. It is also possible to display wide characters.

[0018]

[Effect of the device]

 As described above, according to the finder device of the present invention, since the lower part lower than the parting line front is formed behind the parting line on the penta receiving surface, burrs are present on the parting line. However, this burr can be absorbed by the thickness of the field frame. This allows the bottom surface of the pentamirror or the pentaprism to be properly placed on the penta reception surface via the field frame. Therefore, it is possible to reliably prevent the pentamirror or the pentaprism from floating, and always maintain the accuracy and strength of the finder device after assembly.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a finder device according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of the finder device shown in FIG.

FIG. 3 is an exploded perspective view showing a finder device according to the present invention.

FIG. 4 is a plan view showing an assembled state of a finder device which is the basis of the present invention.

5 is a rear view of the finder device of FIG. 4. FIG.

6 is a vertical cross-sectional view of the finder device of FIG.

7 is a cross-sectional view showing an enlarged part of a contact portion between a pentamirror and a mirror holder of the finder device shown in FIG.

FIG. 8 is a perspective view showing a single mirror holder of a finder device as a basis of the present invention.

FIG. 9 is a vertical cross-sectional view showing a conventional finder device using a pentaprism.

[Explanation of symbols]

 1 Focus Plate 2 Penta Prism 9 Mirror Receiving Part (Mirror Receiving Surface) 10 Cavity Penta Mirror 11 Roof Surface 12 Third Reflecting Surface 13 Side 14a Rear 14b Projection 15 Slope 20 Mirror Holder (Penta Holder) 20b Insertion Opening 21 Recess 22 Flange 23 Inner side surface 24 Rear side surface 25 Sloping surface 26a Recessed portion (lower part) 26b Mounting surface 45 Photometric lens support groove 59 Lens mounting portion 60 Lens rear support protrusion 62 Image frame (field frame) 63 Burr 64 Focus plate pressing member 65a Convex -Shaped wall portion 65b abutting surface

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[Procedure amendment]

[Submission date] September 29, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Scope of utility model registration request] 1. A pentamirror or a pentaprism;
A pentaholder having a pentagonal receiving surface on which the pentamirror or pentaprism is mounted, the pentaholder being made of a molded product of a synthetic resin material; The penta holder is a viewfinder device of a single-lens reflex camera, wherein a parting line of a molding die is located on the penta receiving surface, and a rear end of the field frame is located in front of the parting line. A finder device for a single-lens reflex camera, characterized in that a lower portion located behind the pentacing line of the penta holder is defined with the parting line as a boundary. 2. The viewfinder device for a single lens reflex camera according to claim 1, wherein the pentamirror has a convex wall portion that engages with the lower portion of the pentaholder at a portion corresponding to the lower portion.