JP2581825Y2 - Viewfinder for single-lens reflex camera - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder device for a single-lens reflex camera, and more particularly to a finder device for a single-lens reflex camera that does not cause a pentamirror or a pentaprism to rise due to burrs that tend to be formed on a parting line.

[0002]

2. Description of the Related Art A viewfinder device of a single-lens reflex camera conventionally forms an image of a subject transmitted through a photographic lens and reflected by a quick return mirror (first mirror) on a focus plate 1 as shown in FIG. An image is formed on the roof surface 3 above the pentaprism (pentagonal roof prism) 2.
After being reflected by the third reflecting surface 4 in front, the light is guided to a loupe lens (eyepiece lens) 36 to obtain an image of a subject without vertical and horizontal inversion.

However, the finder device using the pentaprism has a problem that the processing cost of the prism is high and heavy. Then the roof surface 3 of the pentaprism
In addition, there has been proposed a hollow pentamirror in which only a portion corresponding to the third reflection surface 4 is a reflection mirror. This hollow pentamirror has the advantages that it is lightweight and the manufacturing cost is low because the glass portion of the pentaprism is hollow.

This hollow pentamirror is fixed to a camera body (not shown) via a mirror holder (pentaholder). 4 to 8 show an example thereof. The cavity type pentamirror 10 has a roof surface 11 on the upper left and right of the inner surface, and a third reflecting surface 12 on the front. The hollow pentamirror 10 has a configuration in which the left and right side surfaces 13 and the back surface 14a of the lower portion thereof are formed as substantially vertical surfaces, and the third reflection surface 12 is formed as an inclined surface 15 that projects forward as it goes upward. Is formed. The rear surface 14a integrally has a protruding portion 14b protruding rearward by the thickness of the rear side surface 24 of the mirror holder 20 and to be inserted into the insertion opening 20b of the rear side surface 24. The third reflection surface 12 has a mirror surface formed by vapor deposition in a 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. Are drilled. The concave portion 21 includes left and right inner side surfaces 23, a rear side surface 24, and an inclined surface 25 corresponding to the side surface 13, the rear surface 14, and the inclined surface 15 of the hollow pentamirror 10. At the bottom of the recess 21, a hollow pentamirror 10
, A mirror receiving portion (penta-receiving surface) 9 in the form of an inner peripheral flange for determining the insertion depth thereof is formed. The mirror receiving portion 9 has a mirror mounting surface 26d on which the bottom surface of the hollow pentamirror 10 is directly mounted, and an inner peripheral side (front) of the mirror mounting surface 26d. An image frame mounting portion 26c for storing and mounting an image frame (field frame) 62, which is formed lower than 26d, is provided.

The mirror holder 20 further has an insertion opening 20b corresponding to a loupe lens (not shown) fixed to the camera body side for inserting the projection 14b of the hollow pentamirror 10, and a light beam from the taking lens. 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. The left and right lens rear support projections 60 are formed on the left and right of the lens mounting portion 59, respectively.
0, a lens front support projection 44 is formed in front of each. Between the lens front support protrusion 44 and the lens rear support protrusion 60, a fitting support groove 45 for fitting and supporting left and right projecting support pieces of the photometric lens is formed.

[0007] 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, an image frame (field frame) 62 made of a thin synthetic resin material or the like is mounted on the image frame mounting portion 26c at the bottom of the mirror holder 20, and the hollow pentamirror 10 is inserted into the concave portion 21. The outer peripheral side (rear side) of the bottom surface of the mirror 10 is placed on the mirror mounting surface 26 d and the inner peripheral side (front side) of the bottom surface is placed on the image frame 62, and the hollow penta mirror 10 is coupled to the mirror holder 20.

Incidentally, the mirror holder 20 having such a structure is manufactured by injection molding using a molding die that combines an upper die, a lower die and the like, and an insertion opening 20b is formed in the rear side surface 24. Due to the fact and the presence of the thickness a of the rear side surface 24, it is reasonable to set one of the plurality of parting lines on the basis of the rear side surface 24 because the mold is also easy to configure. . Accordingly, the position where the rear side surface 24 is in contact with the mirror receiving portion 9 when the rear side surface 24 is extended downward is the parting line. Actually, in the mirror holder 20, the image frame mounting portion 26c and the mirror mounting surface 2
The parting line coincides with the boundary line with 6d.

For this reason, burrs 63 (FIG. 7) due to the parting line are likely to occur at the boundary between the image frame mounting portion 26c and the mirror mounting surface 26d. The bottom surface of the pentamirror 10 which should be in close contact with 26d may rise. In this case,
The distance D between the focus plate 1 and the roof surface 11 is deviated, the accuracy is impaired due to the deviation of the optical axis O, and the inconvenience that the strength of the finder device is weakened due to the inability of the pentamirror 10 to adhere. Note that d in FIG. 7 represents a fixed distance from the roof surface 11 to the bottom surface of the pentamirror 10.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a finder device which can prevent a problem such as a pentamirror or a pentaprism inserted into a penta holder from being lifted by burrs, based on the above-mentioned problem awareness.

[0011]

SUMMARY OF THE INVENTION The present invention provides a pentamirror or pentaprism; a pentaholder made of a synthetic resin material having a mounting surface on which the pentamirror or pentaprism is mounted; and a pentamirror or pentaprism. A viewfinder frame for a single-lens reflex camera having a field frame located between a bottom surface and a mounting surface of a penta holder, wherein a recess lower than the mounting surface is formed on the eyepiece lens side behind the mounting surface of the penta holder. While forming, the parting line of the molding die of the penta holder is set at the boundary between the mounting surface and the concave portion, and the viewing frame is set at the rear end from the parting line set at the boundary between the mounting surface and the concave portion. The penta-mirror or penta-prism is mounted on the mounting surface so as to be located in front of the penta-mirror or penta-prism, and engages with the recess of the penta-holder from the bottom surface of the rear end. When that convex wall portion projecting was equipped with a pentagonal mirror or pentaprism in Pentahoruda,
The field frame is sandwiched between the mounting surface of the penta holder and the bottom surface of the penta mirror or penta prism, and burrs generated on the parting line between the penta holder and the penta mirror or penta prism due to the thickness of the field frame. It is characterized by securing a gap of a height that allows for the projection, and positioning the penta-mirror or the penta-prism with respect to the penta-holder by the engagement between the convex wall portion and the concave portion.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 longitudinal sectional view of the finder device, FIG. 2 is a partially enlarged view showing a main part of FIG. 1, and FIG.
FIG. 2 is an exploded perspective view showing the entire finder device. The same parts as those of the finder device which is the basis of the present invention shown in FIGS. 4 to 9 are denoted by the same reference numerals, and the description thereof will be omitted.

The hollow pentamirror 10 of the present embodiment leaves the rear (the right side in the figure) of the bottom surface as a convex wall portion 65a, and forms a space between the bottom surface of the convex wall portion 65a and the roof surface 11. The distance is configured to be the same as the distance d shown in FIG. A contact surface 65b, which is cut out upward by a predetermined distance b, is formed in front (left side in the drawing) of the convex wall portion 65a. The boundary between the contact surface 65b and the convex wall portion 65a substantially coincides with the parting line of the molding die during manufacturing.

The mirror receiving portion 9 of the mirror holder 20 has a mounting surface 26b in front of the parting line.
However, a concave portion (low portion) 26a lower than the mounting surface 26b by a predetermined amount is formed on the rear side. The mounting surface 26b protrudes toward the contact surface 65b, and is configured such that the same distance D as in FIG. 7 can be maintained in a state where the image frame 62 is sandwiched between the mounting surface 26b and the contact surface 65b. I have. As a result, FIG.
, The image frame 62 located on the same plane as the bottom surface of the hollow pentamirror 10, that is, the mirror mounting surface 26d.
In this embodiment, is arranged to be raised to the position of the bottom surface of the convex wall portion 65a. That is, the video frame 62 is located at a distance b higher than that in FIG.
The concave portion 26a has a depth enough to accommodate the convex wall portion 65a inserted with the image frame 62 sandwiched between the mounting surface 26b.

On the other hand, the image frame 6 mounted on the mounting surface 26b
2 is configured to be raised toward the pentamirror 10 by the distance b, so that the portion of the bottom surface of the hollow pentamirror 10 other than the convex wall 65a, that is, the side surface 13 and the inclined surface 15 are illustrated in FIG. 6 is formed shorter by the distance b than that shown in FIG.

Therefore, when assembling the finder device of this embodiment, first, the image frame 62 is inserted into the concave portion 21 of the mirror holder 20 in which the photometric lens is inserted into the lens mounting portion 59, and is mounted on the mounting surface 26b. Keep it. In this case, the rear end of the image frame 62 substantially coincides with the parting line, that is, the boundary between the mounting surface 26b and the concave portion 26a. Then, when the hollow penta-mirror 10 is inserted into the concave portion 21 and its bottom surface is brought into contact with the mirror receiving portion 9, the contact surface 65 b of the penta-mirror 10 is positioned between the mounting surface 26 b and the rear end of the image frame 62. And the convex wall portion 65a is completely inserted (engaged) into the concave portion 26a. The concave portion 26a of the convex wall portion 65a
, The hollow pentamirror 10 is properly positioned on the mirror holder 20. At this time, even if burrs exist at the boundary between the mounting surface 26b, which is a parting line, and the concave portion 26a, the burrs are absorbed by the thickness of the image frame 62. The rear end of the image frame 62 can be properly abutted without being affected by burrs at all, so that the hollow pentamirror 10 does not rise. Thereby, the focus plate 1 and the roof surface 11
Inconsistencies such as deviation in the distance D from the optical axis and deviation of the optical axis O are reliably prevented, and inconveniences such as weakening of the strength of the finder device are not caused. 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 set.
Is larger than the distance c 'in FIG. 7, that is, the space between the image frame 62 and the focus plate 1 is widened, so that the display device (not shown) in the viewfinder inserted into this space is made slightly large. This has the advantage that wide characters can be displayed.

[0018]

As described above, according to the finder device of the present invention, at the parting line position of the penta holder, the burr is formed by interposing the field frame between the mounting surface of the penta holder and the bottom surface of the penta mirror or penta prism. Since a gap having a height that allows for the height of the parting line is ensured, even if burrs exist on the parting line, the burrs can be absorbed by the thickness of the field frame. In addition, the penta holder has a concave portion having a parting line as a boundary behind the mounting surface, and a convex wall portion provided on a penta mirror or a penta prism is engaged with the concave portion. Thereby, the bottom surface of the pentamirror or the pentaprism can be properly positioned on the mounting surface via the field frame. Therefore, the lifting of the pentamirror or the pentaprism can be reliably prevented, and the accuracy and strength of the assembled finder device can always be kept good.

[Brief description of the drawings]

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

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

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

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

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

6 is a longitudinal sectional view of the finder device of FIG.

FIG. 7 is an enlarged sectional view showing a part of a contact portion between a pentamirror and a mirror holder of the finder device of FIG. 4;

FIG. 8 is a perspective view showing a mirror holder of the finder device on which the present invention is based;

FIG. 9 is a longitudinal sectional view showing a conventional finder device using a pentaprism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 focus plate 2 pentaprism 9 mirror receiving portion (mirror receiving surface) 10 hollow pentamirror 11 roof surface 12 third reflecting surface 13 side surface 14 a back surface 14 b projecting portion 15 inclined surface 20 mirror holder (penta holder) 20 b insertion opening 21 concave portion 22 Flange 23 Inner side surface 24 Rear side surface 25 Inclined surface 26a Concave portion (lower portion) 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 Wall 65b contact surface

Claims (1)

(57) [Scope of request for utility model registration] A penta-mirror or penta-prism; a penta-holder having a mounting surface on which the penta-mirror or the penta-prism is mounted; A viewfinder frame for a single-lens reflex camera, comprising: a field frame positioned between the mounting surface and the mounting surface;
A concave portion lower than the mounting surface is formed, and a parting line of a molding die for a penta holder is set at a boundary between the mounting surface and the concave portion. The rear end of the field frame has a boundary between the mounting surface and the concave portion. From the bottom of the rear end of the pentamirror or pentaprism.
When a pentagonal mirror or a pentaprism is mounted on the penta holder, a convex wall portion engaging with the concave portion of the penta holder is protruded, and the field frame is placed between the mounting surface of the penta holder and the bottom surface of the penta mirror or penta prism. Between the penta-holder and the penta-mirror or penta-prism by the thickness of the field frame, ensuring a clearance between the penta-holder and the penta-mirror or the penta-prism with a height that allows for burrs generated on the parting line. A finder device for a single-lens reflex camera, wherein a penta-mirror or a penta-prism is positioned relative to a penta-holder in some cases.