JP3294567B2 - Camera finder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder device for a camera, and more particularly to a finder device including an optical element having a roof reflecting surface.

[0002]

2. Description of the Related Art In recent years, many single-lens reflex cameras having camera bodies of various shapes have been proposed because of the importance of holding. When determining the body shape related to the holding, the outer shape of the finder prism is a problem. For example, in a camera that holds the grip section and the barrel section of the camera, the finder prism is arranged so that the height of the prism section is suppressed as much as possible, and the eye point of the finder is moved rearward on the photographer side. Is often requested. In such a case, a finder using a pentagonal roof prism (hereinafter, referred to as a pentaprism) becomes high in height, and it is also difficult to shift the eye point backward.

Therefore, as a conventional example for meeting the purpose, a finder prism is constituted by combining several triangular prisms. For example, FIG. 9 shows an example of a conventional finder prism, and a triangular prism 1 is shown.
01 and 103 and the roof prism 102. Further, the finder prism for a reflex camera disclosed in Japanese Utility Model Publication No. 56-50372 has three prism parts provided in one body. 57-1
No. 82725, or Japanese Utility Model Application Laid-Open No. 57-18272.
The eye level finder prism of the reflex camera disclosed in Japanese Patent Application Laid-Open No. 6-116 is a finder prism having four prisms. All of the above are finder prisms in which the eye point is shifted backward using the roof prism.

[0004]

However, FIG.
And 50-50
The finder prism disclosed in Japanese Patent No. 372 or the like has an effect of lowering the eye point backward, but a remarkable effect cannot be expected with respect to a reduction in height.

Further, as compared with a finder using a pentaprism, the optical path is extended, and as a result,
There was a problem that the finder image became far away and the finder magnification was reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by providing a reflection surface for reflecting light reflected from a roof surface at a more effective position in a finder device of a camera. It is an object of the present invention to provide a camera finder device which satisfies functions required for a mounted camera by lowering an eye point backward, sufficiently reducing a height, and further shortening an optical path length.

[0007]

SUMMARY OF THE INVENTION A finder device for a camera according to the present invention includes a light incident surface facing a reticle and a first reflection for reflecting incident light from the incident surface downward and obliquely rearward of the camera. Surface, a second reflecting surface for reflecting light from the first reflecting surface obliquely rearward upward in the camera, and a third for reflecting light from the second reflecting surface toward surfaces on the other side. In a finder device for a camera having a roof reflecting surface including a reflecting surface and a fourth reflecting surface, and a fifth reflecting surface for reflecting light reflected from the roof reflecting surface backward, the third reflecting surface and the fifth Each of the four reflecting surfaces is
(2) a primary effective reflection area for reflecting light from the reflecting surface and
Fourth reflective surface or primary effective reflective area of the third reflective surface
And a secondary effective reflection area for reflecting light from
At least one end of the reflecting surface is connected to the third reflecting surface and the
The primary effective reflection area and the secondary effective reflection area of the fourth reflection surface
Near the intersection of the reflection area and these two effective reflection areas
A salmon position, that is provided on the ridge side than on the end portion or its extension line of the third reflecting surface and the roof reflecting surface of the fourth reflecting surface are in contact with the ridge line side opposed to Features.

According to another aspect of the present invention, there is provided a camera finder device comprising: a light incident surface facing a focusing screen; and a first reflecting surface for reflecting incident light from the incident surface downward and obliquely rearward of the camera. A second reflecting surface for reflecting light from the first reflecting surface obliquely backward and upward from the camera; and a third reflecting surface for reflecting light from the second reflecting surface toward surfaces on the other side. and a roof member having a roof reflecting surface made of the fourth reflective surface, through the finder device for a camera having a fifth reflecting surface for reflecting backward the light reflected from the roof reflecting surface, the third reflection surface And the fourth reflection surface
Each is a primary effective reflection area for reflecting light from the second reflection surface.
Area and the first real of the fourth reflecting surface or the third reflecting surface.
Has a secondary effective reflection area that reflects light from the effective reflection area
In addition, at least one end of the fifth reflection surface is connected to the third counter surface.
The primary effective reflection area of the projection surface and the fourth reflection surface
Near the intersection of the first and second effective reflection areas, and the two
A position avoiding the effective reflection area, and provided on a ridge line side where the third reflection surface and the fourth reflection surface are in contact with a surface on which light from the second reflection surface is incident on the roof member or an extension thereof. It is characterized by having been done.

The camera finder device is
There are, the fifth reflecting surface, mosquito light from the roof reflecting surface
Reflects light behind and behind the camera
And

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a longitudinal sectional view of an optical system of a finder device of a camera showing a first embodiment of the present invention, and FIG. 3 is a perspective view of a main part of the finder device. The finder device is formed by a first optical block and a second optical block. The first optical block is formed by a prism 8, and the second optical block is formed by a mirror frame 9 and a mirror 10 which is a plane mirror. Respectively.

The prism 8 is fixed to a mounting table 28, and has a light incident surface 8a facing the focusing screen 6, which is a focusing screen supported by a mounting frame 26, above the main mirror 5, and further has a light incident surface 8a. Incident light L2 from surface 8a
Is a reflecting surface that reflects the light downward and obliquely rearward, and is a corresponding surface of the first reflecting surface 8b coated with the reflective coating and the incident surface 8a, and the reflected light L3 from the reflecting surface 8b is directed upward. It has a second reflecting surface 8c for reflecting obliquely backward and an emitting surface 8d for emitting the reflected light L4 to the next stage, the second optical block.

The mirror frame 9 is a hollow frame supported by the mounting table 28 like the prism 8, and has an entrance opening facing the exit surface 8d. The peripheral surface is provided with a notch having an L-shaped cross section as shown in FIG. Thus, light leakage from between the prism 8 and the mirror frame 9 is prevented. The mirror frame 9 has a roof reflecting surface in which aluminum is vapor-deposited on the inner surface of a roof-shaped shape (see FIG. 2 which is a cross-sectional view taken along line DD of FIG. 1) which is abutted at right angles to reflect incident light. Certain third and fourth reflection surfaces 9a and 9b are provided. Since the slope 9c is a non-reflective surface, a V-shaped groove having a predetermined angle of inclination is provided in a stepped manner.

The light reflected by the third and fourth reflecting surfaces 9a and 9b is respectively reflected by the fourth and fourth reflecting surfaces on the opposite side which are inclined and opposed to each other.
It is assumed that they face the three reflecting surfaces 9b and 9a. That is, light incident on the primary effective reflection region A of the third reflection surface or the primary effective reflection region B of the fourth reflection surface (the region surrounded by a broken line in FIG. 1) is reflected to form the fourth reflection surface. Respectively, or the second effective area A ′ (the area surrounded by the two-dot chain line in FIG. 1) of the third reflecting surface, and is reflected obliquely downward as reflected light L5. .

The mirror 1 is located below the mirror frame 9.
An opening for inserting a zero is provided. Further, a mirror positioning receiving portion 9 for fixing the mirror 10 is provided.
f is provided at a position where it has entered the roof surface.

The mirror 10 has a fifth reflecting surface 10.
a and is fixed to the receiving portion 9f of the mirror frame 9 by adhesion. The reflected light L5 is transmitted to the fifth reflecting surface 1
0a, and the reflected light L6 is incident on a light receiving element 12 including an eyepiece 11 and a condenser lens arranged in parallel behind.

The primary or secondary effective reflection areas A, B, A ', B' on the third and fourth reflection surfaces 9a, 9b are:
These parts are required as reflective surfaces in viewfinder function. However, as shown in FIG. 1, it does not occupy the entire plane of the reflection surfaces 9a and 9b serving as roof portions. Therefore, the height of the finder is made as low as possible,
In order to make the finder optical path length as short as possible, the receiving portion 9f of the mirror 10 penetrates into a range avoiding a portion required as the reflection surface, that is, into a roof portion region other than the regions A, B, A ', and B'. Let me know. That is, the fifth reflecting surface 10a
Is intersected with the ridge line C indicating the edge of the roof surface. Note that the ridge line C indicating the end of the roof portion is shown in FIG.
Corresponds to the ridge line C ′ of the outer shape of the mirror frame 9.

As is clear from FIG. 1, the mirror 10 is a roof member, and is a third reflecting surface 9 of a mirror frame 9.
a, one end of the fourth reflection surface 9b, which is the end facing the ridge line in contact with the fourth reflection surface 9b, is provided on the ridge line side with respect to the ridge line C. Further, the mirror 10 is located at a higher position than the extension of the opening of the mirror frame 9 where the reflected light from the prism 8 is incident.
Is provided on the ridge line side. By thus bringing the mirror 10 closer to the effective reflection surface of the roof portion, the optical path of the reflected light L5 can be shortened, and at the same time, the height of the mirror frame 9 can be set low. The cross-sectional shape of the roof part and the mirror 10 in FIG.
Is shown in

Further, the mirror frame 9 to which the prism 8 and the mirror 10 are fixed as described above is fixed to the mounting table 28,
Further, the focusing screen 6 and the condenser lens 7 are fixed to the mounting frame 26, and the mounting table 28 and the mounting frame 2 are fixed.
6 are fixed to each other. Table 28 and mounting frame 2 described above
6 is an exploded perspective view of FIG. As shown in this figure,
The mounting table 28 has an opening 28d for the prism 8 and a support surface 28a. Also, the support portion 28 of the mirror frame 9
b, 28c, and a projection 9g of the mirror frame 9.
(See FIG. 3). The mirror frame 9 has a recess 28e for positioning and fixing to which the mirror frame 9 is fitted and adhered.

The transmission path of the optical path of the finder device of the present embodiment configured as described above will be described with reference to FIG. 1. First, subject light L0 is taken into the camera along the optical axis 0 via the taking lens 4. It is. Then, the light is reflected upward by the main mirror 5 as finder subject light. At the time of photographing, the main mirror 5 is retracted from the optical axis 0, so that the subject light travels straight as it is and forms an image on the photographic film located via the focal plane shutter unit 15.

On the other hand, the finder object light forms an image on a focusing screen 6, and the image forming light from the focusing screen 6 is incident on a prism 8 via a condenser lens 7, and has a first reflecting surface and a second reflecting surface. And is incident on the mirror frame 9 and the third and fourth roof reflecting surfaces
The light is reflected by the reflecting surface, and is reflected by the fifth reflecting surface 10a on the mirror 10 in a direction in which the eyepiece 11 is located. Then, a finder image is observed at the eye point P, and at the same time, the amount of light is measured by the light receiving element 12. It is assumed that the light incident on the eyepiece 11 is emitted upward by an angle α with respect to the optical axis direction O ′.

As described above, according to the finder device of the present embodiment, the height of the finder device can be kept low by mounting the mirror 10 in the roof portion, and at the same time, the optical path length can be shortened. Can be
Furthermore, it becomes possible to position the eyepiece 11 behind. Further, since the mirror frame 9 having the roof portion is formed of a hollow frame, the weight of the finder device can be reduced. At the same time, the frame can be manufactured by injection molding or the like, and the cost of parts can be reduced.

As shown in FIG. 3, the light receiving elements 12 are arranged in parallel on the side of the eyepiece 11.
This is because the position of the fifth reflecting surface 10a and the eyepiece 11 is very close, so if the light receiving element 12 is disposed above the eyepiece 11, the light receiving element 12 This is because it becomes difficult to receive the subject light.

Next, a single-lens reflex camera equipped with the finder device of the present embodiment will be described with reference to a cross-sectional view of FIG. 5 when the rear cover is opened and a longitudinal cross-sectional view of the camera of FIG. The present camera is characterized by its holding function, and usually has one side of the holding portion which is different from a conventional camera having a holding body portion extending to the left and right of the taking lens. The battery, the spool, and the like that were built in the portion are built in the rear lid. Therefore,
According to this camera, holding grip 1a with right hand
(See FIG. 5), the lens barrel is held with the left hand, and the camera body can be easily photographed in a posture in which the camera body is turned vertically, horizontally, or diagonally.

However, since the battery, spool and the like are built in the rear lid as described above, the rear end face of the camera extends rearward. Therefore, it is necessary to position the eyepiece of the finder behind. Furthermore, as described above, photographing is performed in a posture in which the camera body is rotated at various angles, so that the height of the finder portion is preferably low.

Furthermore, the camera itself, especially the finder, needs to be lightweight. Therefore, in order to satisfy those conditions, the present camera is equipped with the finder device described in the first embodiment. The above camera comprises a camera body 1, a rear lid 2, a strobe unit 2
1, a lens barrel 3, a main mirror 5, a focal plane shutter unit 15, a finder device,
It consists of an eyepiece.

The camera body 1 has a portion for supporting the lens barrel 3 and a holding grip 1a on one side thereof, and a supporting hinge 1c for the rear cover 2 and a supporting hinge 1d for the strobe unit 21. Have. Further, a supporting portion 1b of an eyepiece of the eyepiece 11 and the light receiving element 12 is provided at a rear end corresponding to a position above the rear lid 2. The strobe condenser 23 and the film cartridge 16 are provided in the grip 1a.
Is held.

The rear lid 2 is supported by the hinge portion 1c of the main body 1 and is opened and closed when a film is loaded. The rear lid 2 has a sprocket 17, a spool 18, and a battery 24 inside.
And so on. Then, the film 19 is wound around the spool 18 in an inverted S-shape. In addition, the flash tube 2
2 is also supported by the hinge portion 1d of the main body 1 and can perform a pop-up operation as shown in FIG.

The lens barrel 3 supported by the main body 1 has a photographic lens 4. The subject light taken in from the photographic lens 4 is reflected by a main mirror 5, and the reflected light L 2 is reflected on a focusing screen 6. Forms an image as a finder image. Then, the light enters the finder device via the condenser lens 7. On the other hand, at the time of shooting, the main mirror 5 is in a retracted state, and the subject light L
1 forms an image on the film 19 located via the focal plane shutter unit 15 and photography is performed.

The finder device is the same as the finder device of the first embodiment shown in FIG. 1, and includes a prism 8, a mirror frame 9 having a roof reflection surface, and a mirror 10 having a fifth reflection surface. It is composed of The fifth
The finder light beam reflected by the reflecting surface is incident on the eyepiece, and the observation or photometry of the finder image is performed.

By mounting the finder device of the first embodiment, the present camera having the above-described configuration enables holding with a high degree of freedom in the photographing posture, which is a characteristic of the camera, and makes full use of good operability. Can be.

Next, a finder device according to a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the second optical block is constituted by the hollow mirror frame 9 and the mirror 10, but the finder device of the present embodiment uses a prism having a roof reflection surface in the second optical block. Things. That is, as shown in a vertical sectional view of a main part of the finder device of FIG. 7, the present device is composed of a prism 34 as a first optical element and a roof prism 35 as a second optical element.
And is formed from The prism 34 has the same function as the prism 8 of the first embodiment.

The roof prism 35 uses a prism, and its plan view is shown in FIG. The third and fourth reflecting surfaces 35a and 35b, which are the roof reflecting surfaces, are provided with a reflective coating, and the surface 35c is provided with a non-reflective coating. The roof prism 35 has the same surface as the roof reflection surface of the mirror frame 9 of the first embodiment. Further, a fifth reflection surface 35f coated with reflection is provided below the roof reflection surface. This reflecting surface 35f is similar to the mirror 10 of the first embodiment,
With the third and fourth reflection surfaces 35a and 35b, which are the roof reflection surfaces, invading the roof portion while avoiding necessary portions,
A fifth reflection surface 35f is provided in a manner to bite into a ridge line C which is an end of the roof reflection surface. That is, as is clear from FIG. 7, the fifth reflecting surface 35 f has one end portion that is closer to the ridge line C where the third reflecting surface 35 a and the fourth reflecting surface 35 b are in contact with each other than the ridge line C. It is provided on the ridge side. Further, it is provided closer to the ridge than the extension of the incident surface 35d on which the reflected light from the prism 34 is incident.

In this finder device, the subject light is reflected upward by the main mirror 31 and passes through the focusing screen 32 and the condenser lens 33.
The light is incident on the light incident surface 34a of the prism 34, and the incident light L12 is reflected on the first reflecting surface 3 which is a reflecting coating surface.
At 4b, the light is reflected obliquely downward and backward. Then, the reflected light L13 is reflected obliquely upward on the second reflection surface 34c. Then, the reflected light L14 exits from the exit surface 34d and enters the roof prism 35 from the entrance surface 35d. Then, the third reflection surface 35a and the fourth reflection surface 35b
In the above, the incident light L14 is reflected, and the fourth reflecting surface 35b and the third reflecting surface 3 of the opposing reflecting surfaces facing each other.
Go to 5a. Further, the light L15 reflected by the reflecting surfaces 35b and 35a is reflected by the fifth reflecting surface 35f and is reflected by the eyepiece 36.
To the rear where the light receiving elements 37 are arranged side by side,
Injected through.

As described above, according to the finder device of the present embodiment, similarly to the first embodiment, the eye point P can be shifted backward, and at the same time, the fifth reflecting surface 35f is moved to the roof portion. By invading the region, the height of the finder itself can be kept low, and the finder optical path length can be shortened.
Further, the finder according to the present embodiment has a roof portion formed of a prism, so that the finder having excellent optical accuracy can be provided.

[0035]

As described above, in the finder device for a camera according to the present invention, a reflecting surface for reflecting the light emitted from the roof reflecting surface in a predetermined direction is provided on the ridge side where the roof reflecting surfaces are in contact with each other. According to the present invention, the eye point of the finder can be shifted backward, that is, the eyepiece can be moved backward, and at the same time, the height of the finder device can be kept low. Things. Further, since the finder optical path length can be set shorter, it is possible to provide a finder device having a remarkable effect such that the finder magnification is not reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a finder device of a camera according to a first embodiment of the present invention;

FIG. 2 is a sectional view taken along the line DD of FIG. 1;

FIG. 3 is a perspective view of an essential part of the finder device of FIG. 1;

FIG. 4 is an exploded perspective view of a prism mounting table and a screen mounting table in the finder of FIG. 1;

FIG. 5 is a cross-sectional view of the camera equipped with the finder device of FIG. 1 when the rear cover is opened,

FIG. 6 is a longitudinal sectional view of a main part of the camera of FIG. 5,

FIG. 7 is a longitudinal sectional view of a main part of a finder device showing a second embodiment of the present invention,

FIG. 8 is a plan view of a roof prism used in the finder device of FIG. 7,

FIG. 9 is a longitudinal sectional view of a main part of a finder device showing a conventional example.

Continuation of the front page (56) References JP-A-61-6601 (JP, A) JP-A-57-182725 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 13 / 00-13/28

Claims (3)

(57) [Claims] 1. A light incident surface facing a focusing screen, a first reflecting surface for reflecting incident light from the incident surface downward and obliquely rearward of the camera, and a light from the first reflecting surface being reflected by the camera. A second reflecting surface that reflects upward and obliquely rearward, and a roof reflecting surface including a third reflecting surface and a fourth reflecting surface that reflect light from the second reflecting surface toward surfaces on the other side. And a fifth reflecting surface for reflecting light reflected from the roof reflecting surface backward, wherein each of the third reflecting surface and the fourth reflecting surface is a second reflecting surface.
Primary effective reflection area for reflecting these lights and the fourth reflection surface
Alternatively, light from the primary effective reflection area of the third reflection surface
A second effective reflection area for reflecting light, wherein at least one end of the fifth reflection surface is the third reflection surface
And the first effective reflection area of the fourth reflection surface and 2
Near the intersection of the next effective reflection area and these two effective reflection areas
A position avoiding the reflection area, wherein the third reflection surface and the fourth
A finder device for a camera, wherein the finder device is provided on an edge of the roof reflecting surface on a side facing a ridge line in contact with the reflecting surface or on an edge of the roof reflecting surface. 2. A light incident surface facing the reticle, a first reflecting surface for reflecting incident light from the incident surface downward and obliquely rearward of the camera, and a light from the first reflecting surface being reflected by the camera. And a roof reflecting surface including a third reflecting surface and a fourth reflecting surface for reflecting light from the second reflecting surface toward surfaces on the other side. In a finder device for a camera having a roof member having the above-mentioned roof member and a fifth reflection surface for reflecting the reflected light from the roof reflection surface backward, each of the third reflection surface and the fourth reflection surface is a second reflection surface. Reflective surface
Primary effective reflection area for reflecting these lights and the fourth reflection surface
Alternatively, light from the primary effective reflection area of the third reflection surface
A second effective reflection area for reflecting light, wherein at least one end of the fifth reflection surface is the third reflection surface
And the first effective reflection area of the fourth reflection surface and 2
Near the intersection of the next effective reflection area and these two effective reflection areas
A position avoiding the reflection area , provided on a ridge line side where the third reflection surface and the fourth reflection surface are in contact with a surface on which light from the second reflection surface is incident on the roof member or an extension thereof. A camera finder device. 3. The fifth reflecting surface is located at a distance from the roof reflecting surface.
Light reflected from behind the camera and obliquely upward.
3. The finder device for a camera according to claim 1, wherein: