JP2005017403A - Focal board fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focal board fixing device for enabling the accurate positioning of a focal board. <P>SOLUTION: In the focusing glass fixing device incorporated into a single-lens reflex camera photographing unit 1, the focusing glass 24 is mounted on a unit frame 21 of a focusing glass unit 4, and supported in the state in which it is orthogonal to a finder optical axis O2. The unit frame 21 is fixed to be positioned by inserting support pins 10e and 10f or the like provided on a right and left unit mounting face 10b and a rearward unit mounting face 10c of a front plate block 10 respectively in support holes 21h and 21i or the like of the unit frame 21. A spacer 27 is inserted in the support pin so that the focusing glass 24 is positioned at a prescribed arrangement position to a photographing optical axis O1 and the finder optical axis O2, and the unit frame 21 is fixed in the state in which it sandwiches the spacer 27. Thus, the focusing glass 24 is supported in the state in which it has good precision to the front plate block 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a focusing screen fixing device that fixes a focusing screen in a finder device or the like.
[0002]
[Prior art]
Conventionally, the thing of patent documents 1 proposed as a focusing screen fixing device with which a focusing screen can be exchanged is what a focusing screen arranged under a pentaprism is attached to a focusing screen mounting plate, When exchanging the focusing screen, the focusing screen can be exchanged by rotating the focusing screen mounting plate to a state where the focusing screen can be attached and detached. The focusing screen mounting plate is formed of a thin metal plate, and the focusing screen is supported by the mounting plate and positioned in contact with the camera body.
[0003]
[Patent Literature]
Patent document 1 is Unexamined-Japanese-Patent No. 56-107222.
[0004]
[Problems to be solved by the invention]
However, in the focusing screen fixing device described in Patent Document 1, the mounting plate that supports the focusing screen is easily deformed, and accurate positioning of the focusing screen is difficult.
[0005]
The present invention has been made to solve the above-described problems, and an object thereof is to provide a focusing screen fixing device capable of accurately positioning the focusing screen.
[0006]
[Means for Solving the Problems]
The focusing screen fixing device according to claim 1 of the present invention is a focusing screen fixing device for fixing the focusing screen, which has a pair of positioning projections for determining a position on a plane orthogonal to the optical axis direction. A focusing plate unit having a pair of positioning recesses that hold the focusing plate and fit with the pair of projections to determine a position on a plane perpendicular to the optical axis direction of the focusing plate; A pair of convex portions and a pair of concave portions for fixing the focal plate unit to the pedestal portion, and a distance plate that fits with a portion to determine a position of the focal plate unit in the optical axis direction. A focal point for holding the focusing screen, having a spring member that presses the pair of fitting portions of the pair of convex portions and the pair of concave portions with a spring biasing force in a state of being fitted with the space plate interposed therebetween. The plate unit is fixed to the base part by the spring member. It is.
[0007]
The focusing screen fixing device according to claim 2 of the present invention is the focusing screen fixing device for fixing the focusing screen, the platform having a pair of positioning recesses for determining a position on a plane orthogonal to the direction of the optical ring, A focusing screen unit having a pair of positioning projections for holding the focusing screen and fitting with the pair of recesses to determine a position on a plane perpendicular to the optical axis direction of the focusing screen; and fitting with the projections In combination, the distance plate for determining the position of the focusing screen unit in the optical axis direction, and the pair of convex portions and the pair of concave portions for fixing the focusing screen unit to the base portion, The focusing screen unit that holds the focusing screen has a spring member that presses a pair of fitting portions of the pair of convex portions and the pair of concave portions with a spring biasing force in a state of being sandwiched and fitted. , Applied to the base by the spring member It is fixed.
[0008]
The focusing screen fixing device according to claim 3 of the present invention is the focusing screen fixing device according to claim 1 or 2, wherein the pair of convex portions and the pair of concave portions are between the pair of fitting portions. A screw member for pressing the spring member is disposed on the surface.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of a single-lens reflex photographing unit to which a focus fixing device according to an embodiment of the present invention is applied. FIG. 2 is an exploded perspective view of a focusing screen unit incorporated in the photographing unit. 3 is a view taken in the direction of arrow B in FIG. 4 is a cross-sectional view taken along the line CC of FIG. 5 is a cross-sectional view taken along the line AA in FIG.
[0010]
In the following description, the illustrated Z direction parallel to the photographing optical axis O is the front-rear direction, the subject side is the front, and the imaging side is the rear. The illustrated X direction perpendicular to the Z direction is the left-right direction. The Y direction shown in the figure perpendicular to the Z direction is the up-down direction.
[0011]
The single-lens reflex photographing unit 1 of this embodiment includes a mirror unit 2, an AF (autofocus) auxiliary light unit 3, a focusing screen unit 4, an eyepiece finder unit 5, and an image sensor. (CCD) is provided.
[0012]
The mirror unit 2 includes a lens mount portion 11 provided in a mount opening on the photographing optical axis O1 on the front surface of the front plate block 10, and a main mirror 12 rotatably disposed behind the mount opening portion. Become. The main mirror 12 is positioned obliquely on the photographing optical axis O1 when not photographing (viewer observation state), and retracts upward from the optical axis O1 when photographing. When the main mirror 12 is inclined on the optical axis O1, the subject light is reflected upward along the finder optical axis O2 by the main mirror 12.
[0013]
The AF auxiliary light unit 3 has an AF auxiliary light projecting lens 13 a and is arranged in the upper left part of the front plate block 10.
[0014]
The eyepiece finder unit 5 includes a pentaprism 16 fixed on a finder base 15 by a fixing member 17 and an eyepiece unit 6. The eyepiece finder unit is fixed by screwing screws 33 and 34 into screw holes 10m to 10q on the upper surface portion of the finder side opening 10a located above the front plate block 10.
[0015]
The imaging unit includes a CCD mounting plate 16 disposed on the photographing optical axis O1 behind the main mirror 12 and a CCD substrate 15 on which the CCD is mounted.
[0016]
The focusing screen unit 4 is a unit that is disposed on the finder side opening 10a above the main mirror 12 and holds the focusing screen 24 of the finder optical system. The focusing screen 24 can be exchanged from the opening of the lens mount 11. As shown in FIG. 2, the focusing screen unit 4 includes a unit frame 21 fixed on the finder opening 10a, a focusing screen holding frame 22 rotatably supported by the unit frame 21, and a frame support shaft 26. , A field mask 25, a focusing screen 24 that can be attached to and detached from the focusing screen holding frame 22, and a focusing screen locking spring 23.
[0017]
The unit frame 21 is a highly rigid frame-shaped resin or metal molding member, and includes an opening 21a on the finder optical axis O2 and a focusing screen mounting surface on the lower surface side (the finder optical axis O2 in the assembled state). 21b (along the orthogonal plane), positioning support holes 21h, 21i and 21k, 21m, which are positioning recesses provided in a pair of support protrusions protruding outward from the left and right sides of the frame, and the frame Support holes 21j and 21n which are positioning recesses provided at the support protrusions at the lower end portions on both sides of the rear side, shaft holes 21c and 21d provided along the left-right direction at the rear of the frame, and screw screw holes at the front of the frame 21f and a detent pin 21g.
[0018]
The focusing screen holding frame 22 is a frame-shaped metal plate press-molded member, and includes a frame-shaped fitting portion 22a to which the focusing screen 24 can be attached, and a convex portion 22b arranged on the left and right sides of the bottom of the frame-shaped fitting portion 22a. And a shaft support portion 22c extending in the left-right direction at the rear side portion of the frame portion, and a locking projection 22d protruding from the front side portion of the frame portion.
[0019]
The focusing screen 24 is formed of a transparent optical member, and the upper surface thereof forms a mat surface 24b. The focusing screen 24 is removably fitted into the frame-like fitting portion 22a of the focusing screen holding frame 22. In this fitted state, the lower surface portion of the focusing screen 24 abuts on the convex portion 22b. Moreover, it has the knob part 24a which protrudes in the front part.
[0020]
The focusing screen locking spring 23 is a metal plate spring member, and includes a locking hole 23c, a screw insertion hole 23a, a rotation stopping hole 23b, and a knob portion 23d.
[0021]
In the focusing screen unit 4 having the above-described configuration, the field mask 25 is positioned and bonded and fixed to the field mask mounting surface on the upper surface of the unit frame 21 by the pins 21e and the positioning holes 25a. A focusing screen locking spring 23 is fixed to the front surface of the unit frame 21 by screwing a screw 35 inserted through the screw insertion hole 23a into the screw screw hole 21f. Further, the frame support shaft 26 is inserted into the shaft holes 21 c and 21 d of the unit frame 21, and at the same time, the shaft support portion 22 c of the focusing screen holding frame 22 is inserted, and the focusing screen holding frame 22 is rotated to the lower portion of the unit frame 21. Install freely. With the focusing screen holding frame 22 mounted, the focusing screen 24 is inserted into the frame fitting portion 22a of the focusing screen holding frame 22 and attached. The focusing screen holding frame 22 is rotated above the unit frame 21 so that the locking projection 22d is locked in the locking hole 23c of the focusing screen locking spring 23. In this state, the focusing screen holding frame 22 to which the focusing screen 24 is attached is fixed to the unit frame 21 and unitized as the focusing screen unit 4.
[0022]
In the unitized focusing screen unit 4 described above, when the locking projection 22d is locked, the focusing screen 24 is in pressure contact with the lower surface side focusing screen mounting surface 21b of the unit frame 21, as shown in FIG. , Held in close contact. In the holding state, the center of the left and right end portions of the lower surface of the focusing screen 24 is pressed by the convex portion 22b of the focusing screen holding frame 22 with an appropriate pressing force while slightly deforming the focusing screen holding frame 22 side. The end of the mat surface of the plate 24 is held in contact with the lower surface side focusing plate mounting surface 21 b of the unit frame 21. Therefore, the focusing screen 24 is mounted without being deformed.
[0023]
As shown in FIG. 1, the focusing screen unit 4 includes a left and right unit mounting surface 10b and a unit mounting surface 10b that form a platform perpendicular to the finder optical axis O2 around the finder opening 10a of the front plate block 10. From the support hole of the unit frame 21 on the rear unit mounting surface 10c below a predetermined distance.
[0024]
That is, the support holes 21h, 21i and 21k, 21m of the unit frame 21 are inserted into the left positioning pins 10e, 10f and the right positioning pins 10i, 10j, which are two positioning convex portions provided on the left and right unit mounting surfaces 10b. Further, the support holes 21j and 21n of the unit frame 21 are fitted into the positioning pins 10g and 10k which are two positioning convex portions provided on the rear unit mounting surface 10c. The positioning pins 10e and 10i are positioned so that the mat surface 24b of the focusing screen 24 is located at a predetermined distance from the optical axis O1 of the front plate block 10 and the perpendicularity to the finder optical axis O2 with a predetermined accuracy. The spacers 27 having various thicknesses are inserted into the positioning pins 10g and 10k (FIG. 5). The spacer 27 is a thin ring-shaped interval plate (Kanza), and the thickness thereof is determined by the mat surface height and the perpendicularity measurement result before fixing the unit frame 21 described later.
[0025]
A convex boss having a screw screw hole 10d is arranged between the positioning pins 10e and 10f on the left side of the unit mounting surface 10b, and between the positioning pins 10i and 10j on the right side of the unit mounting surface 10b. A convex boss having a screw screw hole 10h is arranged.
[0026]
As described above, the holding plates 28, 29, which are spring members, are inserted into the screw screw holes 10d, 10h of the left and right bosses with the support holes of the unit frame 21 inserted into the positioning pins of the unit mounting surfaces 10b, 10c. Screws 31 and 32 of screw members inserted through the screw insertion holes are screwed. As shown in FIG. 5, the pressing plates 28 and 29 have downward protruding portions 28 a and 28 b and 29 a and 29 b at both ends.
[0027]
Therefore, the upper surfaces of the left support holes 21h and 21i and the right support holes 21k and 21m of the unit frame 21 are pressed by the convex portions of the pressing plates 28 and 29 by screwing the screws 31 and 32, respectively. The adjustment sheet 7 is held in close contact with and fixed to the unit mounting surfaces 10b and 10c of the plate unit 10.
[0028]
Here, the mat surface measuring method before the unit frame 21 is fixed will be described. First, the support holes of the unit frame 21 in which the focusing screen 24 is mounted are inserted into the positioning pins of the unit mounting surfaces 10b and 10c without the spacer 27 being inserted. The upper portions of the left support holes 21h and 21i and the right support holes 21k and 21m are pressed and held with a predetermined pressing force. In the pressed state, the height and inclination of the mat surface 24b on the upper surface of the focusing screen 24, that is, the distance from the optical axis O1 and the perpendicularity to the finder optical axis O2 are measured. Based on the measurement result, the mat surface 24b of the focusing screen 24 is positioned at a predetermined distance from the optical axis O1 (a position equivalent to the imaging plane position of the CCD) and orthogonal to the finder optical axis O2. The thicknesses of the spacers 27 to be inserted below the positioning pins of the unit mounting surfaces 10b and 10c are obtained by calculation.
[0029]
Thereafter, spacers 27 having respective calculated thicknesses are inserted under the positioning pins 10e, 10g and 10i, 10k of the unit mounting surfaces 10b, 10c, and the unit frame 21 of the focusing screen unit 4 is held down as described above. It is fixed to the unit mounting surface via 28 and 29. In this fixed state, the mat surface 24b of the focusing screen 24 is held at a predetermined distance from the optical axis O1 and orthogonal to the finder optical axis O2.
[0030]
The focusing plate 24 attached to the unit mounting surface of the front plate block 10 via the unit frame 21 of the focusing screen unit 4 can be exchanged through the opening of the lens mount portion 11. That is, when the knob 23d of the focusing screen locking spring 23 on the unit frame 21 side is grasped with tweezers and the locking projection 22d of the focusing screen holding frame 22 is unlocked, the focusing screen holding frame 22 rotates downward. Moving. In this rotating state, the focusing screen 24 can be detached from the focusing screen holding frame 22 by grasping the knob portion 24a of the focusing screen 24 with tweezers. Then, another focusing plate 24 to be mounted is mounted by being fitted to the frame fitting portion 22 a of the focusing screen holding frame 22, and the focusing screen holding frame 22 is rotated upward again, so that the focusing screen locking spring 23 When the locking projection 22d is locked in the locking hole 23c, the focusing screen 24 is positioned at a predetermined focusing screen position on the finder opening 10a.
[0031]
In the above-described digital camera incorporating the photographing unit 1 of the present embodiment, when an interchangeable lens barrel (not shown) is attached to the mount unit 11 in the assembled state of the focusing screen 24, the subject image formed on the focusing screen 24 is displayed. Observation with the eyepiece unit 6 becomes possible.
[0032]
As described above, in the focusing screen unit 4 incorporated in the photographing unit 1 of the present embodiment, the position of the focusing screen unit 4 is adjusted by the spacer 27 and the pressing is performed by the pressing plates 28 and 29 of the spring member. The focusing screen 24 is held in pressure contact with and closely attached to the focusing screen mounting surface 21b with respect to the unit frame 21 attached. In this holding state, the focusing screen 24 can be accurately positioned without being deformed.
[0033]
The support holes 21h, 21i and 21k, 21m and the support holes 21j, 21n, which are positioning recesses provided in the unit frame 21, and the recesses provided in the left and right unit mounting surfaces 10b of the front plate block 10 are fitted. The positioning pins 10e, 10f and 10i, 10j and the positioning pins 10g, 10k, which are positioning convex portions to be positioned, can be provided by replacing the concave portions and the convex portions. That is, it is also possible to provide a support pin for each part that is a positioning convex part on the unit frame 21 side, and to provide a support hole for each part that is a positioning concave part on the unit mounting surface of the front plate block 10.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a focusing screen fixing device capable of accurately positioning the focusing screen.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a single-lens reflex photographing unit to which a focus fixing device according to an embodiment of the present invention is applied.
2 is an exploded perspective view of a focusing screen unit incorporated in the photographing unit of FIG. 1. FIG.
FIG. 3 is a view taken in the direction of arrow B in FIG. 2;
4 is a cross-sectional view taken along the line CC of FIG.
FIG. 5 is a cross-sectional view taken along the line AA of FIG.
[Explanation of symbols]
4. Focusing plate unit 10b ... Left and right unit mounting surface (base)
10c ... Rear unit mounting surface (base)
10e, 10f, 10i, 10j, 10g, 10k ... positioning pin (positioning convex part, fitting part)
21 ... Unit frame (focal plate unit)
21h, 21i, 21k, 21m, 21j, 21n ... support holes (positioning recesses, fitting portions)
27 ... Spacer (interval plate)
28, 29 ... holding plate (spring member)
31, 32 ... Screw (screw member)

Claims (3)

In the focusing screen fixing device for fixing the focusing screen,
A base portion having a pair of positioning convex portions for determining a position on a plane orthogonal to the optical axis direction;
A focusing screen unit having a pair of positioning recesses for holding the focusing screen and fitting the pair of projections to determine a position on a plane orthogonal to the optical axis direction of the focusing screen;
An interval plate that fits with the convex portion and determines the position of the focusing screen unit in the optical axis direction;
In order to fix the focusing screen unit to the pedestal, the pair of convex portions and the pair of concave portions are fitted with the pair of convex portions and the pair of concave portions sandwiched between the spacing plates. A spring member that presses the pair of fitting portions with a spring biasing force;
A focusing screen fixing device. In the focusing screen fixing device for fixing the focusing screen,
A pedestal having a pair of positioning recesses for determining a position on a plane orthogonal to the direction of the halo,
A focusing screen unit that holds the focusing screen and has a pair of positioning projections that fits with the pair of recesses and determines a position on a plane orthogonal to the optical axis direction of the focusing screen;
An interval plate that fits with the convex portion and determines the position of the focusing screen unit in the optical axis direction;
In order to fix the focusing screen unit to the pedestal, the pair of convex portions and the pair of concave portions are fitted with the spacing plate interposed therebetween, and the pair of convex portions and the pair of concave portions are A spring member that presses the pair of fitting portions by a spring biasing force;
A focusing screen fixing device. The focusing screen according to claim 1 or 2, wherein a screw member for pressing the spring member is disposed between the pair of fitting portions between the pair of convex portions and the pair of concave portions. Fixing device.

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