JP2001174880A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera where a focusing screen is easily exchanged and accurately positioned. SOLUTION: This camera is provided with a focusing screen holding member 6 holding the focusing screen 5, a focusing screen positioning member 2c positioning the screen 5, a hinge means 34 capable of turning from a 1st position where the focusing screen is held to a 2nd position where the focusing screen can be attached/detached in the member 6, and a locking means 7 holding the member 6 at the 1st position. The camera is provided with a pressing means making the focusing screen abut on the positioning member, and the pressing means is equipped with a pressing part abutting on the focusing screen. The shape of the abutting part has a specified angle to the side surface of the focusing screen, and the pressing means has energizing force at least in two directions, that is, a positioning direction and an opening direction to the focusing screen so as to realize accurate positioning by easy operation and the release thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focusing screen holding mechanism for a camera having a replaceable focusing screen.

[0002]

2. Description of the Related Art Some conventional cameras have a so-called superimpose function in which a selected distance measurement field of view is superimposed on a subject image in a viewfinder field of view. According to this superimposed display function, the image and the display are overlapped, and the “position” of the display and the “state” of the display are respectively changed to, for example, “automatic distance measurement field of view” and “focus”.
In this sense, it is possible to inform the user very intuitively.

As such a camera, for example, there is a camera proposed in Japanese Patent Application Laid-Open No. 4-345150.
This camera enables superimposed display by disposing a guest-host type liquid crystal display member between a pentaprism and a focusing screen.

Further, recently, with the advance of AF technology, 5
Cameras equipped with a 45-point area AF (focus detection device), which is nine times as large as the point area, have also appeared. In this camera, the AF area is within an elliptical line in the center of the viewfinder viewing screen, and 45 distance measuring points are arranged in the elliptical line, and correspond to 45 distance measuring points by the AF sensor. That the focused frame is displayed in red,
It has a superimposed display function for multipoint ranging.

Further, the superimpose display function is very convenient because it works in conjunction with the line-of-sight input function so that the focus point at the gaze point is displayed in red. I have.

[0006] In these cameras, there is a problem in that the display of the focusing screen and the display of the superimposed display member are shifted. Accordingly, for example, as disclosed in Japanese Utility Model Publication No. 57-37132, a holding frame (screen holding member) for holding a focusing screen, a set position for positioning the holding frame in the optical axis direction of the scoon, and A screen holding mechanism comprising hinge means for swingably supporting the focusing screen between the mounting and dismounting positions for attaching and detaching the focusing screen and locking means for locking the holding frame at the set position, thereby facilitating replacement of the focusing screen. There is also a camera. When adopting such a screen holding mechanism, in order to smoothly attach and detach the focusing screen to and from the holding frame,
Usually, the size (inside dimension) of the holding frame is often made somewhat larger than the outer dimension of the focusing screen.

[0007]

However, in the above-mentioned prior art, if the size of the holding frame is made larger than the outer dimensions of the focusing screen, the focusing screen will play with respect to the holding frame, and the holding frame is set at the set position. There is a problem that the positioning of the focusing screen in a screen orthogonal to the optical axis in a state where the focusing screen is locked is shifted and cannot be performed.

That is, as shown in FIG. 5A, a display center 50 of the superimposing LCD indicating 45 distance measuring points, and a display center 51b of the focusing screen 5 indicating a photometry mark at the center of the screen. , The quality of the viewfinder is greatly impaired, and the original function of informing the user of the correct position on the screen cannot be performed. FIG. 5 (b) shows the LC for superimpose.
This shows a case where the display center 50 of D and the center 51b of the display of the focusing screen are at accurate positions without any displacement in the in-screen direction.

In order to solve such a problem of misalignment, Japanese Patent Application Laid-Open No. 8-54666 discloses a holding member in which a frame portion of a holding frame positioned at a set position is deformed by a pressing force of a spring or the like. A configuration has been proposed in which a backlash is absorbed by contacting a focusing screen.

However, in this configuration, the rigidity of the holding frame itself cannot be increased, so that, for example, it is difficult to say that the positioning accuracy is high when the holding frame is pressed against the camera body to position the focusing screen. .

Japanese Patent Application Laid-Open No. 10-148874 discloses a focusing screen 51a loaded in a screen holding frame 54 and moved from a detachable position to a set position as shown in FIG. The left and right side portions (outer peripheral portion) 51a abut against the distal end of a movable pin 55 which is free to advance and retreat by a fixed pin 53 and a spring 56 which project inside the screen holding frame 54, and are pressed toward the fixed pin 53 side.

At the same time, an elastic deformation provided on the camera body 52 (refers to a mirror box, which extends from the lower part of the mirror to the upper finder part, and a 45-point AF detecting unit is mounted on the lower part of the mirror). By being pressed toward the abutting portion 54b by the locking / pressing member 58, the focusing screen 51a can be positioned in the screen.

However, in this case, FIG. 6B is a side view seen from the side of the upper pressing member 58 in FIG.
As shown in FIG. 6 (c), which is a side view of FIG. 6 (b) viewed from the right side, when the locking portion 58a of the locking and pressing member 58 is pulled up (in the left arrow direction in FIG. 6 (C)). ), Locking portion 58a
Then, the hook 54a of the screen holding frame 54 is released, and the screen holding frame 54 moves from the set position to the attachment / detachment position (in the direction of the downward arrow in FIG. 6C). In this case, the screen holding frame 54 is attached and detached (downward in FIG. 6C).
However, since the focusing screen 51a remains pressed by the fixed pins 53 and the movable pins 55 and does not go down, there is a problem that the focusing screen 51a cannot be easily replaced.

Accordingly, the present invention provides a camera which facilitates replacement of a focusing screen using a screen holding mechanism using a screen holding frame, and which can accurately perform positioning of a focusing screen, particularly, positioning in a screen screen direction. It is intended to provide.

[0015]

According to a first aspect of the present invention, there is provided a focusing screen holding member for holding a focusing screen, and a focusing screen positioning for positioning the focusing screen. A member, hinge means for rotating the focusing screen holding member from a first position for holding the focusing screen to a second position at which the focusing screen can be attached and detached, and moving the focusing screen holding member to the first position A camera having locking means for holding the focusing screen in contact with a positioning member, wherein the pressing means includes a pressing portion for abutting on the focusing screen, and the shape of the abutting portion is the focusing. Screw It has a predetermined angle with respect to emissions aspect, in the camera, characterized in that it comprises a two-way urging force of the opening direction and the positioning direction relative to at least the focusing screen.

According to this configuration, the contacting shape of the pressing portion has a predetermined angle with respect to the side surface of the focusing screen, and at least two biasing forces of an in-plane positioning direction and an opening direction with respect to the focusing screen. With this configuration, the positioning in the surface direction can be accurately performed, and the focusing screen can be easily taken out and replaced.

A specific configuration for realizing the object of the invention according to the present application is as follows.
The positioning of the focusing screen in the lateral direction at the first position is performed by biasing the focusing screen in the positioning direction by the elastic force of the tip of the pressing portion having a predetermined angle with respect to the side surface of the focusing screen. 2. The camera according to claim 1, wherein the outer peripheral portion is contacted with the positioning member.

According to this configuration, the outer peripheral portion of the focusing screen is directly applied to the positioning member (butting portion) on the screen holding frame side by the urging force of the pressing portion having a predetermined angle with respect to the side surface of the focusing screen. The contact makes it possible to realize highly accurate positioning of the focusing screen.

According to another specific configuration for realizing the object of the invention according to the present application, as described in claim 3, when the focusing screen is replaced, the pressing means uses an elastic force at the tip of the pressing portion. 2. The camera according to claim 1, wherein the locking is released by an urging force in an opening direction, and the focusing screen is moved to a detachable second position.

According to this configuration, the screen holding frame is shifted from the first position, that is, the set position, to the second position.
When moving to the position, i.e. open and replaceable,
Since the outer peripheral portion of the focusing screen is directly urged downward at the distal end of the pressing portion, the focusing screen can be easily taken out and replaced simultaneously with the release of the locking of the screen holding frame.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a camera according to an embodiment of the present invention. FIG. 2 is an explanatory view of a screen holding mechanism of the camera shown in FIG. FIG. 3 is an operation explanatory view of the screen holding mechanism shown in FIG. FIG. 4 is a plan view showing the relationship between the superimposition and the focusing screen of the camera shown in FIG.

In FIG. 1, reference numeral 1 denotes a camera main body, 2 denotes a mirror box serving as a reference of a finder optical system fixed in the camera main body, and 3 denotes an interchangeable lens (not shown) fixed to an opening of the mirror box 2. Mount Reference numeral 4 denotes a mirror unit rotatably attached to the mirror box 2, and reference numeral 5 denotes an exchangeable focusing screen, which has a Fresnel lens 5a on a light incident surface and a matt surface 5b on a light exit surface. Reference numeral 6 denotes a screen holding frame on which the focusing screen 5 is exchangeably mounted and which is rotatably supported by the mirror box 2.

Reference numeral 7 denotes a screen holding frame which is formed by a leaf spring and is used to set the screen holding frame 6 at a predetermined position.
Is a locking and pressing member that engages with the hook 6a. The screen holding frame is displaced from the predetermined position by pulling the locking / pressing member 7 in the direction of repulsion. In this state, the focusing screen 5 can be attached to and detached from the screen holding frame 6. Reference numeral 8 denotes a cover that covers the screen holding frame 6 and the locking / pressing member 7 inside the mount 3 and is fixed to the mirror box 2.

Reference numeral 9 denotes a field mask having an opening, which defines the boundary of the screen in the viewfinder field. 10 is a pedestal, 11 is a condenser lens, 12 is a spacer, and 13 is a pentaprism. Portions of the pentaprism 13 other than the entrance surface 13a and the exit surface 13b of the finder optical system light beam are painted black. 16 is an eyepiece,
17 is a protective glass. These constitute a finder optical system.

Reference numeral 19 denotes a high-brightness LED that emits infrared light that can be visually recognized even in a bright subject. Reference numeral 20 denotes a so-called LED for making the LED 19 and the pupil of the photographer have a conjugate imaging relationship to efficiently enter the pupil of the observer. A condenser lens that functions as a condenser lens. Reference numeral 21 denotes a field effect type twisted nematic mode (Twi) in which 45 focus detection areas (AF detection areas) are patterned by a plurality of segments and only the selected segment areas can transmit light.
TN using Stable Nematic Mode)
This is an LCD for superimposition comprising a liquid crystal display.

A light beam emitted from the LED 19 passes through a condensing lens 20, a transmission segment of a superimposing LCD 21, a light projection lens 22, and a light splitter comprising a dichroic mirror that transmits visible light and reflects infrared light. 24
Reach Here, the subject image formed on the focusing screen 5 and the pattern of the transmission segment are displayed in a superimposed manner, and the eyeball 1 is passed through the eyepiece 16 and the protective glass 17.
8 and observed.

In the case of displaying about 5 focus detection points by a conventional camera, the corresponding focus detection points on the reflector are directly illuminated by passing through the corresponding five LEDs through the pentaprism. In this case, a superimposed system for visual recognition is used.
Superimposing is performed in which a virtual image illuminating the pattern of one transmission segment in red or the like is raised in the finder field of view by two dichroic mirrors and a distance measuring point is superimposed.

Reference numeral 25 denotes a known focus detection unit which has 45 points A
For F, 26 is a shutter device, 27 is a back cover, 28
Is an upper cover, 29 is a front cover, 30 is a bottom cover, and these constitute an exterior member of the camera. The viewfinder field of view of such a camera includes an object field 31a as shown in FIG. 5 (b) and an outside field display section for displaying shooting conditions such as shutter speed and aperture value located outside the object field 31a. 31b. The subject visual field 31a displays the subject image formed on the focusing screen 5 and the pattern 21 of the transmission segment of the superimposing LCD 21 in the direction of the finder optical axis in a superimposed manner. Pause display can be performed.

In this embodiment, as shown in FIGS. 4A to 4D, a replacement focusing screen having a photometric mark 5c in the center or a grid 5d is provided as shown in FIGS. Can be selected and mounted.

However, when any of the focusing screens 5 and 5 'is selected, the center of the superimposed display center 50 and the center of the photometric mark 5c and the grid 5d formed on the focusing screens 5 and 5' are properly aligned. Since it is necessary to be able to see, the camera of the present embodiment can easily exchange the focusing screens 5 and 5 ', and attach the mounted focusing screens 5 and 5' to the camera body 1 (mirror box 2). A screen holding mechanism that can be accurately positioned with respect to the screen is provided.

In FIG. 2, FIGS. 2 (a) and 2 (b) respectively show the pressing means (32, 33) according to the present invention.
Spring 32 and the pressing portion (guide portion) at the tip
33 is shown.

As shown in FIG. 2A, the contact portion of the pressing portion 33 at the tip of the pressing means with the side of the focusing screen 5 is formed to be inclined at a predetermined angle. Due to this angle, the focusing screen 5 is pressed in the in-plane direction by the pressing portion 33 at the time of setting, which is the first position (FIG. 2).
At the time of replacement, the focusing screen 5 can be urged in the attaching / detaching direction by the guide portion 33 (the position of FIG. 2B) toward the second position at the time of replacement. As described above, the pressing means has a biasing force in two directions.

FIG. 2C is a plan view showing a state in which the pressing means 32 and 33 are incorporated in the mirror box 2. FIG.
FIG. 2D is a side view of FIG. 2C viewed from the right side, and is a diagram illustrating a second position in a state where the screen holding frame 6 is released. In FIG. 2C, when the screen holding frame 6 (corresponding to the screen holding member described in the claims) is moved from the second position to the first position and set, the focusing screen 5 is moved to the mirror box 2. Is pressed (in the direction of the right arrow in FIG. 2 (c)) against a fixing pin (abutting portion corresponding to the positioning member described in the claims) 2a provided in the above-described manner, thereby performing positioning in the screen direction.

Further, in FIG. 2D, when the screen holding frame 6 moves from the first position to the second position, the guide screen 33 pushes the focusing screen 5 and the second
(The downward arrow in the figure).

As shown in the upper part of FIG. 2 (c) and the right part of FIG. 2 (d), the rear end of the screen holding frame 6 is a hinge bent into a horizontal U-shape as shown in FIG. 6b is provided, and a hook 6
a (FIG. 2D) is formed, the hinge portion 6b is supported by the shaft 34, and the screen holding frame 6 is rotated about the shaft 34 so that the mounted focusing screen 5 is moved to the mirror box 2 in the finder optical axis direction. A first position (position shown in FIG. 3 (c)) to be brought close, and a mirror box 2
And a second position (a position in FIG. 3A) that forms a space for attaching and detaching the focusing screen 5 between the first and second positions.

The screen holding frame 6 has a hinge 6b.
Can slide in the in-plane direction of the mounted focusing screen 5 by sliding in the radial direction with respect to the shaft 34. The member 7 shown in FIGS. 2 and 3 is made of a leaf spring,
It has a locking portion 7a, and engages with the hook portion 6a of the screen holding frame 6 located at the first position to lock the screen holding frame 6 at the set position,
Is a locking and pressing member that presses against the abutting portion 2c.
Thus, positioning in the front-rear direction plane is performed.

On the other hand, the pressing means (32, 33) is located at a position facing the fixing pin (abutting portion) 2a in the horizontal direction in the plane.
Are mounted by being urged in the direction of the fixing pin, and are positioned.

Next, the operation of loading the focusing screen 5 and the operation of the holding mechanism will be described.
With the screen holding frame 6 lowered to the second position as shown in FIG. 3A, the focusing screen 5 is loaded into the screen holding frame 6 as shown in FIG. 3B. In addition, the focusing screen 5 is moved to the screen holding frame 6.
The screen holding frame 6 is made large so that the focusing screen 5 has play in the front, rear, left and right directions in order to make it easier to load the screen.

In this state, the screen holding frame 6 is slid forward by its own weight to a position where the shaft 34 comes into contact with a portion corresponding to the bottom of the horizontal U-shaped groove of the hinge 6b. After loading the focusing screen 5 into the screen holding frame 6,
When the screen holding frame 6 is pushed up toward the first position as shown in FIG. 3 (c), the screen holding frame 6 passes through the opening 6c (see FIG. 2 (d)) formed on the side surface of the screen holding frame 6 and is inclined. While the urging force in the two directions of the pressing means is operated, the focusing screen 5 is first held down in the optical axis direction by the elastic urging force of the guide portion 33 and pressed against the screen holding frame 6, so that the positioning in the vertical direction is performed. At the same time, as shown in FIG. 2C, the pressing portion 33 having an inclined angle comes into contact with the side surface of the focusing screen 5, and the biasing force causes the focusing screen 5 to move right and left (see FIG. 2).
3 (c)), is moved in the in-plane direction, abuts against the fixing pin 5, and operates so as to be positioned in the left-right direction in the plane as shown in FIG. 3 (d).

At the same time, the hook 6a of the screen holding frame 6 comes into contact with the lower slope of the locking and pressing member 7. From this state, the screen holding frame 6 is further moved as shown in FIG.
When pushed up to the position (e), the hook 6a rises along the slope of the locking and pressing member 7, and the locking and pressing member 7 is elastically deformed. The rear end of the focusing screen 5 which is slid rearward (in the case of FIG. 2C or in the case of FIG. 3E, rightward as indicated by the arrow), thereby receiving the elastic force of the locking and pressing member 7. The portion abuts against the abutment portion 2c, and the focusing screen 5 is positioned in the in-plane front-rear direction while being pressed by the abutment portion 2c by the locking and pressing member 7.

When the positioning in the left-right direction by the pressing portion 33 and the positioning in the front-back direction by the locking and pressing member 7 are completed in this way, as shown in FIG.
a engages with the locking portion 7a of the locking and pressing member 7, and the screen holding frame 6 is locked at the first position of the set position.

Next, a case where the focusing screen 5 is replaced, that is, a case where the focusing screen 5 is moved from the first position to the second position will be described. First, FIG.
In the state shown in (f), when the tip of the locking and pressing member 7 is pulled up to the left in the figure, the hook 6
3a is disengaged from the locking portion 7a of the locking and pressing member 7, and FIG.
As shown in (c), at the same time when the screen holding frame 6 is released, the positioning of the focusing screen 5 is released by the urging force of the guide unit 33 in the second position direction (downward). The positioning is released.

When the locking and pressing member 7 is pulled up from this state to the state shown in FIG. 3A, a gap is formed between the hinge portion 6b and the shaft 34, and the screen holding frame 6 is moved to the second position by its own weight. In this state, the focusing screen 5 can be replaced and mounted.

As described above, the focusing screen 5
Is loaded into the screen holding frame 6, and the screen holding frame 6
Is pushed up to the first position, positioning in the in-plane left-right direction is performed by the pressing portion 33, then positioning in the in-plane front-rear direction is performed by the locking and pressing member 7, and furthermore, in the finder optical axis direction ( Positioning in the vertical direction is performed by the guide part 33 of the pressing means and the locking and pressing member 7. As a result, the focusing screen 5 is accurately positioned with respect to the mirror box 2 in the in-plane direction and the optical axis direction.

When the focusing screen 5 is replaced, when the locking and pressing member 7 is pulled up in the releasing direction, first, the positioning in the front-rear direction by the abutting portion 2c and the locking and pressing member 7 is released, and then, The positioning in the left-right direction is released by the pressing means 33, so that the focusing screen 5 can be replaced or the like.

As described above, according to the present embodiment, the screen holding frame 6 can be lowered to the second position so that the focusing screens 5, 5 'can be easily attached to and detached from the screen holding frame 6, and can be set. Sometimes, only by a simple operation of pushing up the screen holding frame 6 from the second position to the first position, the focusing screens 5, 5 'can be accurately and coaxially superimposed on the superimposing LCD 21. it can.

The focusing screen 5 is positioned by the pressing means (32, 33) in one direction (left and right) of the in-plane direction of the focusing screen 5 so far, and is locked and pressed in the other direction (front and rear). Although an example in which positioning is performed by the member 7 has been described, the present invention is not limited to this, and pressing means (32, 33) may be used in both directions.

[0048]

As described above, according to the first aspect of the present invention, a focusing screen holding member for holding a focusing screen, a focusing screen positioning member for positioning the focusing screen, and a focusing screen holding member. In a camera having hinge means for enabling the focusing screen to rotate from a first position for holding the screen to a second position at which the focusing screen can be attached and detached, and locking means for holding the focusing screen holding member at the first position, The pressing screen has a pressing unit that abuts the positioning member, the pressing unit includes a pressing unit that abuts the focusing screen, and the shape of the abutting unit has a predetermined angle with respect to a side surface of the focusing screen, Few Both because it has two directions urging force of the opening direction and the positioning direction relative focusing screen enables accurate positioning of the focusing screen, there is an effect that the exchange of the focusing screen is facilitated.

Further, according to a second aspect of the present invention, the pressing means determines the position of the focusing screen in the first position in the side direction at a predetermined angle with respect to the side surface of the focusing screen. Since the outer peripheral portion of the focusing screen is configured to be brought into contact with the positioning member by the urging force in the positioning direction due to the elastic force of the elastic force, by performing the superimpose display on the focusing screen positioned with high precision, There is an effect that a high-quality finder in which the center of the superimposed display and the center of the display on the focusing screen are matched can be constructed.

Further, according to the third aspect of the present invention, when the focusing screen is replaced, the locking means is released by the urging force in the opening direction by the elastic force of the distal end of the pressing portion, and the focusing screen can be detached. Since the configuration is such that the focusing screen is moved to the second position, there is an effect that the focusing screen can be easily exchanged with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a sectional view of a camera according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a screen holding mechanism of the camera shown in FIG.

FIG. 3 is an operation explanatory view of the screen holding mechanism shown in FIG. 2;

FIG. 4 is a plan view showing a relationship between a superimposition and a focusing screen of the camera shown in FIG.

FIG. 5 is a plan view showing a relationship between a superimposition and a focusing screen of a conventional camera.

FIG. 6 is an explanatory diagram of a screen holding mechanism of a conventional camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera main body 2 Mirror box 3 Mount 4 Mirror unit 5 Focusing screen 6 Screen holding frame 7 Locking and pressing member 8 Cover 9 Field mask 10 Base 11 Condenser lens 12 Spacer 13 Penta prism 16 Eyepiece 17 Protective glass 18 Eyeball 19 LED 20 Condenser lens 21 LCD for superimposing 22 Projector lens 23 Beam splitter 24 Optical spectroscope 25 Focus detection unit 26 Shutter 27 Back cover 28 Top cover 29 Front cover 30 Bottom cover 32 Guide spring 33 Guide (pressing portion) 34 Axis

Claims (3)

[Claims] 1. A focusing screen holding member for holding a focusing screen, a focusing screen positioning member for positioning a focusing screen, and a focusing screen detachably attached to the focusing screen holding member from a first position for holding the focusing screen. A camera having hinge means rotatable to a second position and locking means for holding the focusing screen holding member at the first position, comprising: pressing means for bringing the focusing screen into contact with a positioning member; The pressing means includes a pressing portion that comes into contact with the focusing screen, and the shape of the contact portion has a predetermined angle with respect to a side surface of the focusing screen, and at least with respect to the focusing screen. Camera, characterized in that it comprises a two-way urging force of the opening direction and-decided Me direction. 2. The positioning device according to claim 1, wherein the pressing unit determines a position of the focusing screen in a side direction at a first position by an elastic force of a tip of the pressing unit having a predetermined angle with respect to a side surface of the focusing screen. 2. The camera according to claim 1, wherein an outer peripheral portion of the focusing screen is brought into contact with the positioning member by an urging force in a positioning direction. 3. The replacement of the focusing screen by a biasing force in an opening direction due to an elastic force of a tip of the pressing portion when the focusing screen is replaced, and the pressing means is moved to a second position where the focusing screen can be attached and detached. The camera according to claim 1, wherein the camera is moved.