JPH026436Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a mirror device for a single-lens reflex camera, specifically, a movable photometric mirror used for focus detection, etc., in conjunction with the movement of a movable observation mirror. The present invention relates to a mirror device for a single-lens reflex camera which is rotatable so that a light-transmitting part of the movable observation mirror is closed by a photometric movable mirror when the movable observation mirror is raised.

In a single-lens reflex camera, a movable photometric mirror 2 is rotatably provided behind a movable observation mirror 1, as shown in FIG. 1, for focus detection and the like. This photometric movable mirror 2
can be rotated in conjunction with the movable observation mirror 1, and before the shutter release, the movable observation mirror 1 is placed in the photographing optical path as shown in the figure.
The photometric movable mirror 2 is positioned downward at an angle of 45 degrees, and is opened at the rear of the observation movable mirror 1 at a substantially right angle to the movable observation mirror 1. The object light that has passed through the photographic lens 3 is reflected by the movable observation mirror 1 and guided to the focusing glass 4, pentaprism 5, and finder eyepiece 6 in the viewfinder section, and some of the light is reflected by the movable observation mirror 1. It passes through the semi-transparent part (or transparent part) 1a of 1, is totally reflected by the photometric movable mirror 2, and is placed at a position conjugate with the focusing glass 4 and the surface of the film 8, outside the lower photographing optical path. It is designed to be guided to a photoreceptor 7 for photometry. Then, when the movable observation mirror 1 rotates and rises in the direction of the focusing glass 4 by the shutter release, the movable photometry mirror 2 also moves half of the way relative to the movable observation mirror 1. The movable mirrors 1 and 2 rotate upward so as to close the transparent part 1a.
is stopped horizontally in a folded state at positions 1A and 2A shown by dashed lines outside the photographing optical path, and at the same time blocks reverse incident light from the viewfinder eyepiece 6. In this state, the subject light transmitted through the photographic lens 3 is imaged on the film 8 and photographed.

By the way, when performing focus detection using the photoreceptor 7, the photoreceptor 7 is attached to the film 8 as described above.
It is necessary to place it at a position conjugate to the plane of , that is, at a position where distances A and B in FIG. 1 are equal. On the other hand, the path of the light incident on the lower edge of the film 8, that is, the light from above the subject, is as shown by the broken line C, and the photoreceptor 7 must be placed outside this optical path. Considering the above circumstances, the photometric movable mirror 2 must be installed at a position in front of the film 8 at a certain distance. However, as the photometric movable mirror 2 is moved forward along the lens optical axis, the amount of light incident above the optical axis on the photometric movable mirror 2 decreases.

In order to prevent this decrease in the incident component, it is conceivable to shift the photometric movable mirror 2 upward as shown by arrow D, but in this case, the following problems will occur. That is, as the first mirror 2
Shifting upward means that the distance A becomes shorter, and as a result, the photoreceptor 7 must be raised in the direction of the arrow E, thereby cutting off the optical path C from above the subject. In order to prevent this, it is necessary to provide a re-imaging lens above the photoreceptor, which complicates the structure. Second, there is a focal plane shutter curtain (not shown) between the mirror 2 and the film 8, and the distance between the mirror 2 and the shutter curtain is important from the viewpoint of downsizing the camera body. It is not possible to take a dimension with much margin, and as the mirror 2 rises in the D direction, the two end up in contact with each other. Therefore, in order to take in as much of the incident light component above the optical axis as possible without raising the mirror 2 as described above, the mirror surface of the photometric movable mirror 2 must be
It is conceivable to form it as close as possible to the movable observation mirror 1, but in this case, when the end of the mirror surface of the movable photometry mirror 2 is brought close to the movable observation mirror 1, the movable observation mirror 1 The vicinity of the center of rotation of the movable photometric mirror 2 is inserted, and a gap is created between the movable observation mirror 1 and the movable photometric mirror 2 in the vicinity of the center of rotation.

However, if the gap is formed with the movable observation mirror 1 raised, the reverse incident light from the viewfinder eyepiece 6 will enter the mirror box through the semi-transparent part 1a of the movable observation mirror 1 and the gap. However, there is a problem in that the effect of closing the semi-transparent part 1a of the movable observation mirror 1 with the movable photometry mirror 2 is reduced, and it becomes necessary to close the gap by some means. .

In view of the above points, the purpose of the present invention is to bring the end of the mirror surface of the photometric movable mirror on the movable observation mirror side as close as possible to the movable observation mirror, and to fill the gap created by this with the light shielding member. An object of the present invention is to provide a mirror device for a single-lens reflex camera in which a movable viewing mirror is covered by being disposed on the mirror surface side of a mirror frame that supports a movable viewing mirror.

The present invention will be explained below with reference to illustrated embodiments.

Figures 2A and B show a mirror device according to an embodiment of the present invention, with the movable observation mirror in a lowered state, and Figures 3A and B show the same mirror device in a state in which the movable observation mirror is raised. are shown respectively. A movable observation mirror (hereinafter simply referred to as an observation mirror) 11 is rotatably attached to a side wall (not shown) of a mirror box by means of a support shaft 13 installed at the upper end of both side walls 12a of a mirror frame 12. The photometric movable mirror (hereinafter simply referred to as photometric mirror) 14 is attached to the side wall 15a of the photometric mirror frame 15.
It is rotatably attached to the observation mirror 11 by a support shaft 16 provided through the side wall 12a of the mirror frame 12.

The mirror 17 of the observation mirror 11 is arranged parallel to the bottom plate 12b of the mirror frame 12, with a slight distance from the bottom plate 12b. That is, mirror 1
7, one end of the side far from the support shaft 13 is connected to a mirror holder 18 integrally provided on the front wall 12c of the mirror frame 12, and a mirror stop 19 with an inclined surface facing the holder 18. Therefore, the other end of the mirror 17, which is held between them and is closer to the support shaft 13, is connected to the mirror frame 12.
is placed on the stepped portion of the rear wall 12d, and the rear wall 12d
The mirror 17 is fixed to the mirror frame 12 by being pressed toward the bottom plate 12b by a pressing spring 20 disposed through the hole 12e. Semi-transparent part 1 of the mirror 17 of the bottom plate 12b
A light-transmitting opening 21 is formed in the portion facing 7a, and the photometric mirror 14 is disposed in this opening 21. This opening 21 is connected to the observation mirror 11 as shown in FIG. 2B.
When the photometering mirror 14 and the photometering mirror 14 are placed in the pre-photographing state tilted at approximately 45 degrees in opposite directions, the convergent light from the phototaking lens 3 (see Fig. 1) is transmitted through the photometering mirror 14. The aperture shape is sufficiently larger than that of the total reflection mirror 22. The mirror 22 of the photometric mirror 14 is directly fixed by adhesive or the like to the upper surface of the mirror support part 15b, which is a bottom plate of the photometric mirror frame 15 and is made of a strong and flat metal plate such as iron or stainless steel. A light shielding cover 23 made of a lightweight material such as plastic is fixed to the lower surface of the support portion 15b. This light shielding cover 23 is the mirror support part 1
It extends long forward from the front end of 5b, and is formed in a size sufficient to cover the opening 21 in the state shown in FIG. 3B. A peripheral edge 23a of the light shielding cover 23 slightly protrudes toward the rib 12f so as to cover the rib 12f of the opening 21. The rib 12f of the opening 21 is connected to the light shielding cover 2.
3 covers the opening 21, the light-shielding cover 23 comes into contact and completely closes the opening 21, serving to prevent reverse incident light from leaking into the mirror box. This rib 12f is the bottom plate 1 of the mirror frame 12.
2b, but in addition to this, a relatively flexible light shielding member such as moltoprene may be bonded to the same portion.

When the photometric mirror 14 is approximately perpendicular to the observation mirror 11 (see FIG. 2B), the end of the mirror 22 on the support shaft 16 side, due to the above-mentioned reason,
That is, the rear end of the photometric mirror 14 is extended to a position slightly beyond the support shaft 16 so that the rear end can be as close to the mirror 17 of the observation mirror 11 as possible. The photometric mirror 14 is the mirror 2.
Since the mirror support part 15b and the light-shielding cover 23 are integrally provided on the mirror 2 and have a predetermined thickness, when the mirror 14 is stationary at approximately right angles to the observation mirror 11, A predetermined gap 24 is formed between the end and the rear edge of the opening 21 of the observation mirror 11 so that the end does not come into contact with the rear edge of the opening 21 . This gap 24 is formed to be large as shown in FIG. 3B when the observation mirror 11 is raised. Therefore, as shown in FIG. 4, the opening 2 of the mirror frame 12
One end edge 25a of a flexible sheet-like light shielding member 25 is adhered to a part of the bottom plate 12b near 1, and the rear part of the opening 21 is covered by this light shielding member 25, The other free edge extends above the rear end of the photometric mirror 14.

Therefore, this light shielding member 25 closes the gap 24,
It will be covered from the top surface (see Figures 2B and 3B).

On the other hand, a substantially elliptical cam hole 26 is formed in one side wall (not shown) of the mirror box, as shown by the dashed line in FIGS. 2A and 3A.
A guide pin 27 that can appropriately abut on the operating edge of the cam hole 26 is attached to the mirror frame 15 of the photometric mirror 14.
The mirror box is installed at the rear of the side wall 15a opposite to one side wall of the mirror box. This side wall 15a
The part where the guide pin 27 is fixed, that is, the rear part of the side wall 15a, completely covers the cam hole 26 and prevents light from entering the mirror box when the observation mirror 11 is in the raised state. hole 26
It has a larger-shaped covering portion 15c. The front part of the side wall 15a covers the side part of the mirror 22, and the lower end part slightly forward of the support shaft 16 is provided with a second (see Figure A), an escape groove 15d is formed so that rotation is not hindered by a drive spring 28, which will be described later.

The observation mirror 11 is driven by a well-known means (not shown), and the photometry mirror 14 is interlocked with the rotation of the observation mirror 11 and is extended between the observation mirror 11 and the photometry mirror 14. It is designed to be driven by the provided driving spring 28, the cam hole 26, and the guide pin 27. The drive spring 28 is formed of a linear spring having a substantially U-shape and which applies a biasing force in a direction in which both ends move toward each other when the drive spring 28 is attached. That is, the drive spring 28 is located between the side wall 12a of the observation mirror 11 and the side wall 15a of the photometric mirror 14, and with both ends opened against the biasing force, one end is attached to the observation mirror 11. The support shaft 16 of the side wall 12a
is locked in a locking groove 12h of a fork-shaped protrusion 12g formed at the lower part of the photometric mirror 14.
It is locked in a locking hole 15e formed in the side wall 15a of the support shaft 16 at a position slightly diagonally above and rearward of the support shaft 16. Therefore, the observation mirror 11 and the photometry mirror 1
4, a tightening force is always acting between the portions where both ends of the drive spring 28 are fixed.

The mirror device configured as described above performs reflection photometry with the viewing mirror 11 lowered as shown in FIGS. 2A and 2B prior to shutter release. That is, the object light transmitted through the photographic lens 3 (see FIG. 1) is reflected by the mirror 17 of the observation mirror 11 and guided to the viewfinder section as observation light, and a part of the object light is transmitted to the semi-transparent section 17a and the transparent section 17a. The light is transmitted through the light aperture 21, reflected by the mirror 22 of the photometric mirror 14, and guided to the photoreceptor 7 for focus detection.

In this state, the rear end of the photometric mirror 14 is close to the observation mirror 11, and the incident component of the light above the optical axis of the photographing lens 3 (see FIG. 1) is increased to the photoreceptor 7.
is leading to Because the light shielding member 25 has its own flexibility, the end on the photometric mirror 14 side is free, so even if the rear end of the photometric mirror 14 protrudes toward the mirror 17 of the observation mirror 11, ,
Following the movement of this photometric mirror 14, the gap 2 is
4. Keep it covered.

When the shutter is released, the observation mirror 11 rotates clockwise about the support shaft 13 and rises by a well-known means. At this time, in conjunction with the rotation of the observation mirror 11, the photometering mirror 14 rotates clockwise around the support shaft 16 with its guide pin 27 being regulated and guided by the operating edge of the cam hole 26. When the photometric mirror 14 has rotated by an angle, that is, when the straight line connecting both ends of the drive spring 28 exceeds the state where it coincides with the support shaft 16, in other words, when the spring 28 has exceeded the consideration point, the photometric mirror 14 rotates clockwise largely and quickly with respect to the observation mirror 11, and then the photometering mirror 14 again rotates toward the observation mirror 1.
The guide pin 27 is moved into the cam hole 26 in conjunction with the rotation of 1.
It rotates while being regulated and guided by the operating edge of. and,
When the observation mirror 11 has risen completely, the photometric mirror 14 has also risen completely, and as shown in FIG.
to close the opening 21.

In this state, the rear end of the photometric mirror 14 separates from the mirror 17 of the observation mirror 11 and from the rear edge of the opening 21, forming a large gap 24. The free end portion follows the rotation of the photometric mirror 14 and comes into contact with the rear edge portion on the mirror 22, and the free end portion follows the rotation of the photometric mirror 14 and contacts the rear edge portion of the mirror 22, and
is covered with a light shielding member 25. Therefore, the light shielding member 25 allows the semi-transparent part 17a of the mirror 17 to be seen from the viewfinder eyepiece (see FIG. 1).
The reverse incident light that has passed through is completely blocked.

In the above state, the subject light transmitted through the photographing lens 3 is projected onto the film 8 (see FIG. 1), and photographing is performed. Then, when the photographing is completed, the observation mirror 11 and the photometry mirror 14 perform the operation opposite to that described above, and again, as shown in FIGS. The photometric mirror 14 also maintains a state substantially perpendicular to the observation mirror 11.

As described above, according to the mirror device of the present invention, by bringing the movable photometric mirror closer to the movable observation mirror, the rear end of the movable photometric mirror and the end of the light transmitting opening can be connected. Since the gap created between them is covered with a light shielding member, it is possible to completely prevent reverse incident light from the viewfinder section when the movable observation mirror is raised, and the rear end of the movable photometry mirror can be covered with a light shielding member. Since it can be brought sufficiently close to the mirror, it is possible to capture a large amount of incident light above the optical axis of the photographic lens, making it particularly effective for use in focus detection devices, and furthermore, it is extremely simple and inexpensive. It exhibits excellent effects such as great utility value depending on the configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a mirror device of a single-lens reflex camera, FIG. 2 A and B are a side view and a sectional view of the mirror device in the mirror lowered state showing an embodiment of the present invention, and FIG. A and B are
The side view and cross-sectional view of the mirror device shown in FIG. 2 above in the mirror raised state, and FIG.
FIG. 3 is a plan view showing a state in which the movable observation mirror of the mirror device shown in the figure is removed; 1, 11...Movable mirror for observation, 2, 14...
Movable mirror for photometry, 3...Photographing lens, 25...
Light shielding member.

Claims (1)

[Scope of Claim for Utility Model Registration] A movable observation mirror for guiding light transmitted through the photographic lens to the viewfinder section is provided movably with respect to a fixed base plate such as a side wall of a mirror box, and the photographic lens and the movable observation mirror In a mirror device for a single-lens reflex camera, the movable observation mirror is provided with a movable photometric mirror for guiding light transmitted through a transparent portion of the mirror to a photoreceptor for photometry, wherein the movable mirror for photometry is rotatably provided. The end portion on the rotation center axis side is provided so as to enter the mirror frame of the movable observation mirror, and the movable observation mirror rises, and the photometry movable mirror closes the light-transmitting part of the movable observation mirror. A mirror device characterized in that a light shielding member is attached to the mirror surface side of the mirror frame for shielding a gap that occurs near the center of rotation of the movable photometric mirror when the movable photometric mirror reaches a position where the movable photometric mirror rotates.