JPH11218803A - Single lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach a finder mirror assembly to a camera main body part in such a system that the assembling work efficiency is made high and the finder mirror assembly is hardly distorted in a single lens reflex camera using the finder mirror assembly. SOLUTION: The single lens reflex camera 10 is equipped with a pentagonal mirror assembly 28 by which a subject image formed on a focusing screen 24 can be observed as an erect image from a finder ocular part 30. By engaging a pair of wire-like springs with two locking parts formed near the lower end of the mirror assembly body 32 of the assembly 28, the assembly 28 is attached to the supporting surface 22 of the camera main body part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera.

[0002]

2. Description of the Related Art The present single-lens reflex camera (hereinafter, referred to as "reflex camera")
Many single-lens reflex cameras have a horizontally extending focusing plate above a quick return mirror, and an eye that allows a subject image formed on the focusing plate to be observed as a top, bottom, left, right normal image. It has a level finder. A method using a pentagonal roof prism (hereinafter, referred to as a pentaprism) is predominantly used as a method for observing the subject image as a vertical, horizontal, or right normal image. In a camera, a method using a finder mirror assembly configured by combining a plurality of mirrors so as to obtain the same optical path configuration as a pentaprism is also used. That is, since the pentaprism is configured such that an optical path is formed by a plurality of reflection surfaces using total reflection of the surface of the optical glass,
By using a finder mirror assembly in which mirrors are provided at positions corresponding to the reflection surfaces of the pentaprism, the same optical action as when a pentaprism is used can be obtained. The finder mirror assembly thus configured will be referred to as a pentamirror assembly in the following description. In a medium-sized camera, when a pentaprism is used, the weight of the pentaprism becomes considerably larger than that of a small camera. Therefore, a method using a pentamirror assembly is more advantageous than a pentaprism.

[0003] The configuration of the pentamirror assembly corresponds to the configuration of the pentaprism. Therefore, the pentamirror assembly reflects a roof mirror that reflects light incident from the reticle and further reflects light reflected by the roof mirror. And a plane mirror for guiding to a viewfinder eyepiece. Many of the pentamirror assemblies have a shell-like mirror assembly body having a roof mirror and a plane mirror provided inside. The mirror assembly body is not always configured as one component, and may be configured by assembling or engaging a plurality of members.
Among the mirrors of the penta-mirror assembly, there are various methods for forming a flat mirror. In some cases, a flat mirror member formed by depositing a metal film on a plate is attached to the inner surface of the mirror assembly body. On the other hand, the construction method of the Dach mirror generally produces a part forming at least a part of the mirror assembly body as a plastic molded article having a pair of inward flat surfaces which intersect at right angles to each other, and the pair of inward It is formed by depositing a metal film on a flat surface. In most cases, it is not easy to form a roof mirror with sufficient performance at a low cost, and thus, in most cases, the roof mirror of the pentamirror assembly is configured by this method.

[0004] To explain this further, in a pentaprism or pentamirror assembly, the mirror surface butting portion at the center of the roof mirror is located at the center of the field of view. Not done. Therefore, it is impossible to use an easy method of abutting two glass mirrors at right angles. According to the current state of the art, a method of manufacturing a roof mirror having a mirror surface abutting portion so precise that it can be used for a finder is to form a pair of outwardly facing planes that intersect at right angles with each other on the surface of the prism, and form these planes. Utilize total internal reflection, or otherwise, form a pair of inward planes that intersect at right angles to each other on the surface of the precision plastic molded product, and deposit metal such as silver on those planes to make a mirror surface However, only two methods are practical. Needless to say, a pentaprism is formed by using a total reflection of the prism surface to form a roof mirror, and a pentamirror assembly is formed by using a precision plastic molded product. Therefore, the pentamirror assembly has a plastic shell-shaped mirror assembly body provided with a plurality of mirror surfaces inside.

[0005] The wall of the shell-shaped mirror assembly body is constructed to be quite thin, but rather than to reduce the weight, it is necessary to obtain the shape accuracy of the roof mirror. It is being done. That is,
Since the roof mirror forming portion is constituted by walls which are abutted at right angles, the abutting portion forms a shape unique portion, and a plastic molded product is liable to be distorted in the shape unique portion at the time of manufacturing. More specifically, if a plastic molded product has a corner having a shape in which two walls are abutted at a right angle, the inner corner side of the corner has heat in the cooling process after injection molding and is difficult to cool down. On the other hand, the outside corner side is very easy to cool. This difference in cooling rate causes distortion in the plastic molded article, but the difference in cooling rate becomes smaller as the wall thickness of the plastic molded article is reduced. Conversely, if the wall thickness is increased, a large distortion occurs and the accuracy of the shape of the roof mirror cannot be obtained, so that the wall thickness of the mirror assembly body must be reduced.

[0006]

The thin wall thickness of the mirror assembly body is advantageous for weight reduction, but on the other hand it has the problem of insufficient rigidity. That is, when the pentamirror assembly is attached to the camera body (camera chassis or the like), if a force is applied to the mirror assembly body, the pentamirror assembly is easily elastically deformed. Even if the distortion of the mirror surface is very small, the image of the subject in the viewfinder may be greatly distorted and very unsightly. For example, if a screw is used to attach a pentamirror assembly by screwing, a very strong force acts on the tightened portion of the screw and a twisting force also acts, so that a considerably large distortion is applied to the pentamirror assembly. This is highly likely to occur and is therefore unsuitable for screw mounting. In addition, with regard to the attachment of a normal plastic part, a method of fitting and snap-fitting using the elasticity of the plastic part is often used, but if this method is used to attach a pentamirror assembly,
Since the residual elastic force is required to maintain the mounted state, the residual elastic force may cause distortion in the pentamirror assembly. Therefore, this method is also unsuitable for mounting a pentamirror assembly.

[0007] For these reasons, adhesives are often used at present to attach the pentamirror assembly to the camera body. However, it is difficult to use an instant adhesive which is excellent in terms of work efficiency, because when using an instant adhesive, it is necessary to apply a pressing force to the bonding surface, and the process of applying the force This is because there is a very high possibility that the pentamirror assembly will be distorted and adhered in that state. Also, while many adhesives decrease in volume upon curing, a large amount of the adhesive may distort the viewfinder mirror assembly during the curing process. For these reasons, silicone rubber-based adhesives have been favorably used. The reason is that although the silicone rubber adhesive slightly reduces its volume during curing, the amount of the decrease is small, and since it remains soft after curing, the cured adhesive itself deforms, causing This is because the occurrence of distortion of the mirror assembly is prevented or reduced.

However, the silicone rubber-based adhesive has a problem that the working efficiency is low due to a slow curing speed, and a large amount of the silicone rubber-based adhesive easily leaks to surrounding mechanical parts before being cured. If the amount of use is reduced, there is a problem that the holding power of the pentamirror assembly may be insufficient. The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a single-lens reflex camera using a finder mirror assembly, which has a high assembly work efficiency and a method in which distortion is hardly generated in the finder mirror assembly. Accordingly, it is an object of the present invention to enable the finder mirror assembly to be attached to the camera body.

[0009]

In order to achieve the above-mentioned object, the present invention provides an image pickup apparatus comprising: A finder mirror assembly disposed above the reticle, wherein the finder mirror assembly further reflects the light incident on the reticle and light reflected by the roof mirror, and contacts the finder mirror. A mirror assembly body provided with a plane mirror for guiding to the eye, the mirror assembly body having a top wall portion and a peripheral wall portion, and a lower portion facing the reticle is formed in an open shape; An engagement portion for engaging a spring is formed near a lower end of the peripheral wall portion, and the finder mirror assembly includes a camera. The viewfinder mirror assembly is mounted on the camera body by being placed on an upward support surface formed on the body and applying a downward biasing force to the engagement portion by a spring. Features. In addition, the present invention is characterized in that the peripheral wall portion of the mirror assembly body has a front wall portion in which the flat mirror is provided on an inner surface, a rear wall portion in which an opening facing the finder eyepiece is formed, Left and right side wall portions extending to the left and right side walls, and the engaging portion is provided on each of the left and right side wall portions.
It is characterized by being formed one by one. Also, in the present invention, each of the engagement portions may be formed in the shape of a ridge extending laterally from the side wall portion of the mirror assembly body and extending in the front-rear direction along the side wall portion. Features. Further, the present invention is a wire-shaped spring provided with one spring corresponding to each of the engagement portions, and the wire-shaped spring extends in the front-rear direction of the single-lens reflex camera. And both ends thereof are locked by the camera body, and are engaged with the engaging portion at a central portion. Further, the present invention is a leaf spring in which one of the springs is provided corresponding to each of the engagement portions, and the leaf spring extends in a front-rear direction of the single-lens reflex camera, and has one end. Are engaged with the camera body and the other end is engaged with the engagement portion. Further, the present invention is characterized in that an engagement portion for positioning the finder mirror assembly in a horizontal direction is formed between the mirror assembly body and the support surface of the camera body.
Further, the present invention is characterized in that the mirror assembly body is made of plastic, and at least a portion of the mirror assembly body where the roof mirror is formed is formed of a plastic molded product. The present invention also provides a single-lens reflex camera, which includes a finder mirror assembly that allows a subject image formed on a focusing screen to be observed from a finder eyepiece, wherein the finder mirror assembly has a shell shape with an open bottom. The camera has a mirror assembly body, and the finder mirror assembly is attached to the camera body by a spring that engages with an engagement portion formed on the mirror assembly body.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a single-lens reflex camera according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional side view of a single-lens reflex camera according to an embodiment of the present invention, FIG. 2 is a side view of a finder mirror assembly used in the single-lens reflex camera of FIG. 1 and a supporting portion thereof, and FIG. FIG. 4 is a cross-sectional view of the finder mirror assembly and its support along the line AA in FIG. 2. In the following description, as in the case of the description of the related art, a single-lens reflex camera is simply called a single-lens reflex camera, and a pentagonal roof prism is simply called a pentaprism.

FIG. 1 is a sectional side view of a medium-sized single-lens reflex camera 10 according to an embodiment of the present invention, in which a photographing lens is removed and only a camera body 12 is shown. The camera body 12 includes a lens mount 14, a quick return mirror 16, and a focal plane shutter 18. A focusing plate (focusing plate) 24 extending horizontally is disposed above the quick return mirror 18.
A subject image is formed on the focusing screen 24 by the photographing lens. The single-lens reflex camera 10 includes an eye level finder 26. The eye level finder 26
A finder mirror assembly 28 is provided above the focusing screen 24. The subject image formed on the focusing screen 24 is observed from the finder eyepiece 30 as a vertical, horizontal, and right normal image by the finder mirror assembly 28. I can do it.

The finder mirror assembly 28 is constructed by combining a plurality of mirrors so that the same optical path configuration as that of the pentaprism can be obtained. Call. The pentamirror assembly 28 has a mirror-shaped mirror assembly body 32 made of plastic. The mirror assembly body 32 has a shape in which a lower portion facing the reticle 24 and a rear portion facing the loupe ball 34 of the finder eyepiece 30 are open, and light incident from the reticle 24 (the optical axis of this light is A roof mirror 36 that reflects light L1 shown in FIG. 1), and a plane mirror 38 that further reflects the light reflected by the roof mirror 36 (the optical axis of this light is shown L2) and guides the light to the finder eyepiece 30. Are provided inside.

FIGS. 2 to 4 show a pentamirror assembly 2.
8 and the support portion 20 of the camera body (camera chassis or the like) supporting the pentamirror assembly 28 are shown in detail. As shown, the support 20 has a horizontal support surface 22 facing upward. In order to mount the pentamirror assembly 28 to the camera body, the pentamirror assembly 28 is mounted and mounted on the support surface 22 formed on the camera body, which will be described in more detail later. . 1 and FIG.
As shown in FIG. 7, a rectangular opening 20a corresponding to the shape of the focusing screen 24 is formed, and light enters the inside of the pentamirror assembly 28 from the focusing screen 24 through the opening 20a.

In the mirror assembly body 32, a front wall portion defining a forming portion of the plane mirror 38 is formed as one member by separating it from other portions, and the other portion is formed as another member. After being formed, these two members are joined and integrated. The latter member defines the lower opening of the mirror assembly body 32, the rear opening, and the formation of the roof mirror 36. Also,
Each of these two members is a precision plastic molded product, so that the formation part of the roof mirror 36 and the formation part of the plane mirror 38 form a high-precision plane, and the positions and angles of the formation parts. Is manufactured so as to be a design value with high accuracy. As is well known to those skilled in the art, the formation part of the roof mirror 36 is formed by a pair of inward planes which intersect at right angles as shown in FIG. Metal is deposited on the formation part of the roof mirror 36 and the formation part of the plane mirror 38 to form a mirror surface. As a metal to be deposited, a metal having a high reflectance is used, and for example, silver, aluminum, or the like can be used.

The mirror assembly body 32 thus formed has a top wall and a peripheral wall, and the reticle 24
The lower part facing to is open. As shown in FIG. 3, the top wall has a pair of substantially trapezoidal walls 40 and a substantially isosceles triangular wall 42 in front of the pair, and the pair of trapezoidal walls 40 is perpendicular to each other. And a roof mirror 36 is formed on the inner surface thereof. As shown in FIGS. 2 and 4, the peripheral wall portion includes a front wall portion 44 having a flat mirror 38 provided on an inner surface thereof, a rear wall portion 46 having an opening 46 a facing the finder eyepiece 30, It has left and right side walls 48 extending in the front-rear direction. Further, in order to attach the pentamirror assembly 28 to the camera body, an engaging portion 50 for engaging a spring is formed near the lower end of the peripheral wall of the mirror assembly body 32. In the embodiment, one engaging portion 50 is formed on each of the left and right side wall portions 48. Each of the engagement portions 50 is formed in the shape of a ridge projecting sideways from the side wall portion 48 and extending in the front-rear direction along the side wall portion 48.

In the illustrated embodiment, the spring used to attach the pentamirror assembly 28 to the camera body is a wire spring 52 provided one for each of the engaging portions 50. is there. Those two
The wire-shaped spring 52 is provided in the single-lens reflex camera 1
0, and more specifically, extends along the left and right side walls 48 of the pentamirror assembly 28 mounted on the above-described upward support surface 22. Both ends of each wire spring 52 are fitted and locked in holes provided in the support portion 20 of the camera body, and are engaged with the upper surface of the engagement portion 50 at the center.
Therefore, when the springs 52 apply downward biasing force to the engaging portions 50 on the left and right sides of the pentamirror assembly 28 placed on the upward supporting surface 22, the pentamirror assembly 28 is moved downward by the camera body. Attached to.

As a procedure for mounting the pentamirror assembly 28, for example, the pentamirror assembly 28 is first placed on the support surface 22 and the spring 52
May be inserted into the insertion holes formed in the support portion 20 and attached. Alternatively, as an alternative, the two springs 52 are first attached to the support 20 in the same manner, and the center of the springs 52 is bent laterally outward using tweezers or the like, and the The mirror assembly 28 may be placed on the support surface 22 and then the center of the springs 52 may be placed on the upper surface of the engagement portion 50, which may be advantageous in terms of working efficiency. .

After the pentamirror assembly 28 is mounted, the horizontal position of the pentamirror assembly 28 is fixed by the static friction force acting on the contact portion between the lower end of the mirror assembly body 32 and the support surface 22. Is done. However, if the static friction force is insufficient, an engagement portion for positioning the pentamirror assembly 28 in the horizontal direction may be formed between the lower end of the mirror assembly body 32 and the support surface 22. This positioning engagement portion is provided, for example, by providing two pin-shaped protrusions at one of the lower end of the mirror assembly body 32 and the support surface 22 and, at the other end, one round hole corresponding to the cross-sectional shape of the pin-shaped protrusion. And one long hole. In addition, other configurations are possible, but it should be avoided to adopt a configuration in which a strong force that distorts the mirror assembly body 32 is applied.

The spring used for mounting the pentamirror assembly 28 is the wire spring 52 described above.
Not only that, other forms can also be used. For example, it is conceivable to provide one leaf spring for each of the left and right engaging portions 50 of the pentamirror assembly 28. In this case, each of the leaf springs extends in the front-rear direction of the single-lens reflex camera 10, that is, extends along the left and right side walls 48 of the pentamirror assembly 28 mounted on the support surface 22. Then, one end of each leaf spring may be engaged with the support portion 20 of the camera body, and the other end may be engaged with the upper surface of the engagement portion 50 of the pentamirror assembly 28.

The mounting structure of the pentamirror assembly described above has a structure in which the mirror assembly body is made of plastic and at least a roof mirror of the mirror assembly body is formed as in the embodiment disclosed herein. This is particularly advantageous when the part is made of a high-precision plastic molded product. This is because, as described with respect to the problem to be solved by the present invention, the pentamirror assembly having such a configuration is easily elastically deformed when an external force is applied, and easily causes distortion of the subject image in the finder. . In the embodiment disclosed above, since the adhesive having a low curing speed is not used, the working efficiency of the assembling work can be improved, and the spring 52 is attached to the engaging portion 50 provided near the lower end of the mirror assembly body 32. The pentamirror assembly 28 is unlikely to be distorted because the pentamirror assembly 28 is attached by applying the urging force. Further, by providing the engaging portions 50 on the left and right sides of the mirror assembly body 32, the shape of the engaging portions 50 is also formed as a ridge extending along the side wall portion 48 of the mirror assembly body 32. This also makes it difficult for the pentamirror assembly 28 to be distorted. Further, the use of the wire-shaped spring 52 extending in the front-rear direction also helps to prevent the pentamirror assembly 28 from being localized due to the force.

[0021]

As is apparent from the above description, the single-lens reflex camera according to the present invention is provided with a finder mirror assembly for enabling the subject image formed on the reticle to be observed from the finder eyepiece. The finder mirror assembly has a shell-like mirror assembly body with an open bottom. Then, when attaching the finder mirror assembly to the camera body, a spring is engaged with an engagement portion formed on the mirror assembly body.
Therefore, the working efficiency of the assembling work can be improved, and the occurrence of distortion in the mirror assembly body during the assembling work can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional side view of a single-lens reflex camera according to an embodiment of the present invention.

FIG. 2 is a side view of a finder mirror assembly used in the single-lens reflex camera of FIG. 1 and a supporting portion thereof.

FIG. 3 is a plan view of a finder mirror assembly and a supporting portion thereof.

FIG. 4 is a cross-sectional view of the finder mirror assembly and a supporting portion thereof taken along line AA of FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Single-lens reflex camera 22 Support surface 24 Focusing plate 28 Finder mirror assembly (pentamirror assembly) 30 Finder eyepiece 32 Mirror assembly body 36 Dach mirror 38 Flat mirror 50 Engagement part 52 Spring

Claims (8)

[Claims] 1. A single-lens reflex camera, wherein a subject image formed on a reticle is arranged above the reticle so that the image can be observed from a finder eyepiece of an eye-level finder as an upper, lower, left and right normal image. A finder mirror assembly, the finder mirror assembly includes a roof mirror that reflects light incident from the focusing screen, and a plane mirror that further reflects the light reflected by the roof mirror and guides the light to the finder eyepiece. A mirror assembly body provided, wherein the mirror assembly body has a top wall portion and a peripheral wall portion, and is formed in a shape in which a lower portion facing the reticle is opened, and near a lower end of the peripheral wall portion, An engagement portion for engaging a spring is formed, and the finder mirror assembly is formed on a camera body. The viewfinder mirror assembly is attached to the camera body by applying a downward biasing force of a spring to the engaging portion. Single-lens reflex camera. 2. The peripheral wall of the mirror assembly body includes: a front wall having the flat mirror provided on an inner surface; a rear wall having an opening facing the finder eyepiece; 2. The single-lens reflex camera according to claim 1, wherein the single-lens reflex camera has left and right side wall portions extending, and the engagement portion is formed on each of the left and right side wall portions. 3. The mirror assembly body according to claim 2, wherein each of the engagement portions is formed in a shape of a ridge extending laterally from the side wall portion of the mirror assembly body and extending in the front-rear direction along the side wall portion. The described single-lens reflex camera. 4. The spring is a wire spring provided one by one corresponding to each of the engagement portions, and the wire spring extends in a front-rear direction of the single-lens reflex camera, The single-lens reflex camera according to claim 3, wherein both ends of the single-lens reflex camera are engaged with the camera body and are engaged with the engaging portion at a central portion. 5. The leaf spring according to claim 1, wherein one of the springs is provided corresponding to each of the engagement portions.
The single-lens reflex camera according to claim 3, wherein the leaf spring extends in a front-rear direction of the single-lens reflex camera, and one end is locked to the camera main body and the other end is engaged with the engagement portion. . 6. An engagement portion for positioning the viewfinder mirror assembly in a horizontal direction is formed between the mirror assembly body and the support surface of the camera body. 2. The single-lens reflex camera according to claim 1. 7. The mirror assembly body according to claim 1, wherein the mirror assembly body is made of plastic, and at least a portion of the mirror assembly body where the roof mirror is formed is made of a plastic molded product. The described single-lens reflex camera. 8. A single-lens reflex camera, comprising: a finder mirror assembly for enabling a subject image formed on a reticle to be observed from a finder eyepiece; wherein the finder mirror assembly is a shell-shaped mirror having an open bottom. A single-lens reflex camera having an assembly body, wherein the finder mirror assembly is attached to the camera body by a spring that engages with an engagement portion formed on the mirror assembly body.