JPH0429223A - Finder device for camera - Google Patents

Abstract

PURPOSE:To obtain this finder device whose eye point is moved backward and height is reduced and optical path length is shortened by making a fifth reflection face, which reflects the reflected light from a roof part backward, in a state avoiding the parts required as reflection faces intrude into the roof part. CONSTITUTION:This device is provided with the roof part having third and fourth reflection faces 9a and 9b which reflect the light from a second reflection face 8c to faces of each other and a fifth reflection face 10a which reflects the reflected light from the roof part backward and the fifth reflection face 10a is intruded into the roof part except parts required as third and fourth reflection faces 9a and 9b. That is, a mirror 10 is provided with the fifth reflection face 10a and stuck to a reception part 9f a mirror frame 9, and the reception part 9f is put in the roof part area except parts required as reflection faces 9a and 9b. Thus, the eye point is shifted backward, and the height is reduced, and the finder optical path length is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a finder device for a camera, and more particularly to a finder device constituted by one prism optical element and an optical element having a roof surface.

[Prior Art] In recent years, many eye reflex cameras have been proposed that have camera bodies of various shapes because holding is important. 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 camera's grip and lens barrel, the finder prism should be arranged so that the height of the prism is kept as low as possible, and the eye point of the finder is moved to the rear on the photographer's side. Things are often requested.

In such a case, a finder using a pentaprism has a high height, and it is also difficult to shift the eye point backward.

Therefore, as a conventional example to meet this purpose, a finder prism was constructed by combining several triangular prisms. For example, FIG. 9 shows an example of a conventional finder prism, with triangular prisms 101 and 10.
3 and a roof prism 102. Further, a finder prism for a reflex camera disclosed in Japanese Utility Model Publication No. 56-53372 has three prism parts provided in one body. Furthermore, Utsukai Sho 57-182725
The eye-level finder prism of the reflex camera disclosed in Japanese Utility Model Publication No. 57-182726 is 4.
This is a finder prism with two prisms. All of the above are finder prisms that use a roof prism to shift the eye point backwards.

[Problems to be Solved by the Invention] However, the finder prism shown in FIG. 9 and the finder prism disclosed in Japanese Utility Model Publication No. 56-53372 have the effect of lowering the eye point to the rear. However, no significant effect can be expected in terms of height reduction.

Furthermore, compared to a finder using a pentaprism, the optical path is elongated, resulting in a problem that the finder image becomes farther away and the finder magnification decreases.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to dispose a fifth reflecting surface that reflects light reflected from a roof surface backward in a camera finder device at a more effective position. It is an object of the present invention to provide a finder device that satisfies the functions required of the camera to which it is mounted, by lowering the point to the rear, sufficiently reducing the height, and shortening the optical path length.

[Means and Effects for Solving the Problems] The camera finder device of the present invention includes a light incident surface facing the focus plate;
a first reflecting surface that reflects the incident light from the incident surface diagonally downward and backward; a second reflecting surface that reflects the light from the first reflecting surface diagonally upward and backward; and the second reflecting surface. A camera comprising: a roof section having a third reflective surface and a fourth reflective surface that reflect light from the roof toward the opposite surface; and a fifth reflective surface that reflects light reflected from the roof section backward. In the finder device, the fifth reflective surface is introduced into the roof part while avoiding a portion of the roof part that is necessary as the third reflective surface and the fourth reflective surface.

[Example] The present invention will be explained 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 Figure 3 is
The perspective view of the principal part of the above-mentioned finder device is shown. 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. Each is composed of:

The prism 8 is fixed to a mounting table 28.

The main mirror 5 has a light entrance surface 8a facing the focusing screen 6 of the focusing plate supported by the mounting frame 26 above the main mirror 5, and further includes an incident light L2 from the entrance surface 8a.
a first reflective surface 8b that is coated with a reflective coating and that reflects the light downward and diagonally backward, and the incident surface 8
Reflected light L3 from the reflecting surface 8b, which is the corresponding surface of a.
It has a second reflecting surface 8c that reflects the light upward and diagonally backward, and an exit surface 8d that emits the reflected light L4 to the next second optical block.

Further, the mirror frame 9 is attached to the mounting table 2 in the same way as the prism 8.
It is a hollow frame supported by 8 and has an entrance opening facing the exit surface 8d, and in order to reflect the incident light, it has a roof-shaped shape (D-- in FIG. No. 3.4 reflective surfaces 9a and 9b, which are roof portions, are provided on the inner surface of the mirror (see FIG. 2, which is a cross-sectional view of D). In order to make the slope 9C a non-reflective surface, it is provided in the form of a groove or a step with a V-shaped cross section and an inclination of a predetermined angle.

The reflected light from the third and fourth reflecting surfaces 9a and 9b is reflected by the reflecting surface 9b of the opposing reflective surface box 43, which is inclined and opposite, respectively.
9a. In other words, the light incident on the primary effective reflection area A of the third reflection surface or the primary effective reflection area B of the fourth reflection surface (the area surrounded by the broken line in FIG. 1) is reflected to the fourth reflection area. The light enters the secondary effective reflection area B' of the surface or the secondary effective area A' (the area surrounded by the two-dot chain line in FIG. 1) of the surface, respectively, and is reflected diagonally downward as reflected light L5. .

Note that an opening for inserting the mirror 10 is provided below the mirror frame 9. Further, a mirror positioning receiving portion 9f for fixing the mirror 10 is provided at a position that penetrates into the roof surface.

Further, the mirror 10 has a fifth reflective surface 10a, and is fixed to the receiving portion 9f of the mirror frame 9 by adhesive. The reflected light L5 is reflected by the node 5 reflecting surface 10a, and the reflected light L6 is incident on a light receiving element 12 including an eyepiece lens 11 and a condenser lens arranged in parallel at the rear.

The primary or secondary effective reflective areas A, B, A', and B' on the third and fourth reflective surfaces 9a and 9b are respectively required as reflective surfaces for the finder function. However, as shown in FIG.
, 9b. Therefore, in order to make the height of the finder part as low as possible and furthermore to make the finder optical path length as short as possible, the mirror 10 is
The receiving portion 9f is made to penetrate into a range avoiding the portion necessary as the reflecting surface, that is, into the roof area other than the areas A, B, A', and B'. That is, the fifth reflective surface 10
A will be positioned to intersect the ridge line C indicating the end of the roof surface. Note that the ridgeline C indicating the end of the roof portion corresponds to the ridgeline C' of the outer shape of the mirror frame 9 in FIG. By bringing the mirror 10 closer to the effective reflection surface of the roof portion in this manner, the optical path of the reflected light L5 becomes shorter, and at the same time, the height of the mirror frame 9 can be set lower. Note that the cross-sectional shape of the roof portion and the mirror 10 taken along the line DD in FIG. 1 is shown in FIG.

Further, as described above, the prism 8 and the mirror frame 9 to which the mirror 10 is fixed are fixed to the mounting table 28, and the screen maturo and condenser lens 7 are fixed to the mounting frame 26, and the mounting table 28 and the mirror frame 9 are fixed to the mounting table 28. Frames 26 are secured together. The fourth exploded perspective view of the mounting base 28 and the mounting frame 26 is shown in FIG.
As shown in the figure. As shown in this figure, the mounting table 28 has an opening 28d for the prism 8 and a support surface 28a.

It also has support parts 28b and 28C for the mirror frame 9, and further has a recess 28e for positioning and fixing the mirror frame 9 into which the projection 9g (see FIG. 3) of the mirror frame 9 is fitted and adhered. ing.

The transmission path of the optical path of the finder device of this embodiment configured as described above will be explained with reference to FIG. 1. First, subject light will be explained. is taken into the camera along the optical axis O via the photographing lens 4. The light is then reflected upward by the main mirror 5 as object light for the finder. At the time of photographing, the main mirror 5 is retracted from the optical axis O, moves straight, and forms an image on the photographic film located via the force sensor unit 15.

On the other hand, the object light for the finder forms an image on the focus screen 6, and the image formed light from the focus screen 6 enters the prism 8 via the condenser lens 7.
It is reflected by the first reflecting surface and the second reflecting surface, enters the mirror frame 9, is reflected by the 3rd and 4th reflecting surface of the roof part, and is reflected by the mirror 10.
Reflected light is emitted from the upper fifth reflecting surface 10a in a certain direction of the eyepiece 11. Then, the finder image is observed at the eyepoint 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 lens 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 this embodiment, the height of the finder device can be kept low by inserting the mirror 10 into the roof part and installing it.
At the same time, the optical path length can be shortened, and furthermore, it becomes possible to position the eyepiece lens 11 at the rear. and,
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, it is also possible to manufacture the frame by injection molding, etc., and it is also possible to reduce component costs.

Note that, as shown in FIG. 3, the light receiving element 12 is arranged in parallel to the side of the eyepiece lens 11. This is because the positions of the fifth reflective surface 10a and the eyepiece 11 are very close to each other, so if the light receiving element 12 is disposed above the eyepiece 11, the light receiving element 12 will be separated from the focusing screen 6. 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 longitudinal cross-sectional view of the camera in FIG. 5 and a cross-sectional view when the rear lid is opened in FIG. 6. This camera is unique in its holding function, and unlike conventional cameras that normally have a holding body extending to the left and right of the photographic lens, the camera eliminates the holding part on one side.
The battery, spool, etc. that were built in that part are now built into the rear lid. Therefore, according to this camera, the holding grip 1a (see Fig. 6) is supported with the right hand, and the lens barrel is held with the left hand.
You can easily take pictures with the camera body rotated vertically, horizontally, or diagonally.

However, as mentioned above, since the battery, spool, etc. are built into the rear cover, the rear end surface of the camera extends rearward. Therefore, the eyepiece of the finder must also be located at the rear. Furthermore,
As mentioned above, since images are taken with the camera body rotated at various angles, it is better if the height of the finder section is lower.

Furthermore, the camera itself, especially the viewfinder, needs to be lightweight. Therefore, in order to satisfy these conditions, this camera is equipped with the finder device shown in the above-mentioned first embodiment.

The camera described above includes a camera body 1, a rear lid 2, a strobe unit 21, a lens barrel 3, a main mirror 5, a shutter unit 15, a finder device, and an eyepiece.

The camera body 1 has a portion that supports the lens barrel 3 and a holding grip 1a on one side thereof, and also includes a supporting hinge portion IC of the rear cover 2 and a strobe unit 21.
It has a supporting hinge part 1d. Further, at the rear end corresponding to the upper position of the rear lid 2, a support portion 1b for the eyepiece lens portion of the eyepiece lens 11 and the light receiving element 12 is provided. A strobe capacitor 23 and a film cartridge 16 are held within the grip portion la.

The rear lid is supported by the hinge portion lc of the main body 1 and is opened and closed when loading film, etc., and has a sprocket 17, a spool 18, a battery 24, etc. built therein. The film 19 is spooled 18 in an inverted S-shape.
be rolled up.

Further, the strobe unit 21 having the flash tube 22 is similarly supported by the hinge portion 1d of the main body 1, and is capable of a hop-up operation as shown in FIG.

The lens barrel 3 supported by the main body has a photographic lens 4, and the subject light captured by the photographic lens 4 is reflected by the main mirror 5, and the reflected light L2 is displayed as a finder image on the focusing screen 6. Form an image. The light then enters the finder device via the condenser lens 7. On the other hand, when shooting, the main mirror 5 is in a retracted state, and the subject light is transmitted to the film 1 located through the focal plane unit 15.
An image is formed on 9 and photographing is performed.

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

By attaching the finder device of the first embodiment to the camera configured as described above, it is possible to hold the camera with a high degree of freedom in photographing posture, which is a feature of the camera, and the good operability can be fully utilized.

Next, the finder device showing the second embodiment of the present invention was installed in the seventh embodiment.
, 8 will be explained. In the first embodiment, the second optical block was composed of a hollow mirror frame 9 and a mirror 10, but in the finder device of this embodiment, the second optical block uses a prism having a roof portion. It is.

That is, as shown in the vertical sectional view of the main part of the finder device in FIG. 7, the present device is formed of a prism 34 as a first optical element and a roof prism 35 as a second optical element. The prism 34 has the same function as the prism 8 of the first embodiment. Also, roof prism 35
uses a prism, and its plan view is shown in No. 8.
As shown in the figure. The third and fourth reflective surfaces 35a which are the roof part
, 35b are coated with a reflective coating, and the surface 35c is coated with a non-reflective coating. The roof portion has a surface having the same shape as the roof surface of the mirror frame 9 of the first embodiment. Furthermore, a fifth reflective surface 35f coated with a reflective coating is provided below the roof portion. This reflective surface'
35f is the third and fourth reflective surfaces 35a of the roof portion, similar to the mirror 10 of the first embodiment.

It is installed in a state where it enters the roof part while avoiding the necessary part of 35b. That is, the fifth reflective surface 35f is provided in a shape that cuts into the ridgeline C that is the end of the roof portion.

In this finder device, the subject light is reflected upward by the main mirror 31, and the focusing screen 3
2 and the condenser lens 33, the incident light is incident from the light incident surface 34a of the prism 34, and the incident light "12
is reflected diagonally downward and backward at the first reflective surface 34b, which is a reflective coating surface. Then, the reflected light "13" is second reflected, and the reflected light L14 is emitted from the exit surface 34d,
The light enters the roof prism 35 from the entrance surface 35d. Then, the incident light L14 is reflected at the third reflective surface 35a and the fourth reflective surface 35b, and is directed toward the fourth reflective surface 35b and the third reflective surface 35a, which are the opposing reflective surfaces facing each other. Furthermore, the reflective surface 35b.

The reflected light L15 at 35a is reflected at the fifth reflective surface 35f and is emitted to the rear where the eyepiece 36 and the light receiving element 37 are arranged side by side through the exit surface 35e.

As described above, according to the finder device of the present embodiment, as in the first embodiment, the eye point P can be moved rearward, and at the same time, the fifth reflective surface 35f can be moved into the roof area. This makes it possible to keep the height of the finder itself low, and also makes it possible to shorten the finder optical path length. Furthermore, since the finder of this embodiment has a roof portion formed of a prism, it is possible to provide an object with excellent optical precision.

[Effects of the Invention] As described above, the camera finder device of the present invention has a structure in which the fifth reflective surface enters the roof area, and according to the present invention, the eye point of the finder In other words, the eyepiece can be moved backward, and at the same time the height of the finder device can be kept low.Furthermore, the finder optical path length can be shortened (as it can be set, the finder magnification can be reduced). It is possible to provide a finder device that has remarkable effects without causing any deterioration of the image quality.

[Brief explanation of drawings]

1 is a longitudinal sectional view of the finder device of a camera according to the first embodiment of the present invention, FIG. 2 is a sectional view taken along line DD in FIG. 1, and FIG. 3 is a sectional view of the finder device in FIG. FIG. 4 is an exploded perspective view of the prism mounting table and screen mount in the finder shown in FIG. 1, and FIG. 5 shows the main parts of the camera equipped with the finder device shown in FIG. 1 above. 6 is a cross-sectional view when the rear cover of the camera shown in FIG. 5 is opened; FIG. 7 is a vertical sectional view of essential parts of a finder device showing a second embodiment of the present invention; FIG. This figure is a plan view of a roof prism used in the finder device shown in FIG. 7, and FIG. 9 is a vertical cross-sectional view of a main part of a conventional finder device. 6.32・・・・・・・・・・・・Focusing screen (focal plate)

Claims (3)

[Claims] (1) A light entrance surface facing the focusing plate, a first reflection surface that reflects the incident light from this entrance surface diagonally downward and backward, and a light from this first reflection surface reflected diagonally upward and backward. A roof part has a second reflective surface to reflect light, a third reflective surface and a fourth reflective surface to reflect light from the second reflective surface to the opposite surface, and a roof part that reflects light from the roof part to the rear. In the camera finder device, the fifth reflective surface is placed inside the roof part while avoiding the portions necessary as the third and fourth reflective surfaces in the roof part. A camera finder device characterized by an intrusion. (2) a first optical block including the light incident surface, the first reflecting surface, and the second reflecting surface; and a second optical block including the third reflecting surface, the fourth reflecting surface, and the fifth reflecting surface. The camera finder device according to claim 1, characterized in that it is formed from an optical block. (3) The camera finder device according to claim 2, wherein the second optical block comprises a hollow frame.