JP3025381B2 - Shading frame for film unit with lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding frame used in a film unit with a lens between a photographing lens and a film.

[0002]

2. Description of the Related Art From the simplicity that the applicant can immediately take a photograph at the place of purchase, and after taking the photograph, the photographer can simply go to a photo processing store.
Film units with lenses such as (trade name) are manufactured and sold, and are widely used in general. This film unit with a lens has a built-in unexposed film in advance in a unit body incorporating a simple photographing mechanism.After performing the film winding operation in the same way as a general camera operation, the shutter button is pressed. Then, the shutter blades open and close, and the subject image is exposed on the film set behind the exposure frame.

The exposure frame limits the exposure range on the film surface. In the conventional film unit with a lens, the exposure frame is integrated into the unit body, and is typically a 24 mm × 36 mm exposure for 35 mm full size. It has an opening. The light passing through the taking lens passes through the exposure aperture and reaches the film. However, in general, light that has not passed directly to the exposure aperture is included in light passing through the taking lens. When such light is reflected and scattered by the inner wall of the unit main body and the like and reaches the film through the exposure aperture, it causes a large cause of so-called flare which lowers the contrast of an image. In order to reduce the flare, a conventional film unit with a lens incorporates a flare prevention frame between the taking lens and the exposure aperture. The anti-flare frame has a small-sized opening with a shape almost similar to the exposure aperture.It has the function of passing the light that has passed through the taking lens toward the exposure aperture and cutting much of the other light. Do.

[0004]

In order to reduce the flare as much as possible, it is advantageous to make the opening shape of the anti-flare frame similar to the exposure opening as described above, but the shape of the exposure opening is not necessarily constant. Not immutable. Particularly recently, many film units with lenses for panoramic photography have been provided, in which case the size of the exposure aperture is "1".
3.7 mm x 36 mm ". Therefore, another anti-flare frame having a different aperture size is required for a film unit with a lens for panoramic photography. In addition, since the film unit with lens is inexpensive and easy to use for each application and function, it is possible to increase the number of models and create a series of products.In addition to panoramic shooting described above, for example, cinerama size and A film unit with a lens having an exposure aperture corresponding to the aspect ratio of an HDTV screen is also being studied.

Under these circumstances, a unit body having a different exposure opening shape for each model is manufactured, and a flare prevention frame having a different opening shape for each model is prepared. Then, an appropriate flare prevention frame must be selected and incorporated, which makes the production troublesome and causes a large cost increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages, and eliminates the trouble of selecting and incorporating a flare prevention frame for each shape of an exposure opening formed in a unit body, and has a lens having a different exposure opening shape. It is an object of the present invention to provide a light-shielding frame for a film unit with a lens, which enables a simple and efficient assembly even for a film unit.

[0007]

In order to achieve the above object, the present invention has a structure in which a light shielding frame is incorporated between a photographic lens and a film, and an exposure opening is provided at the rear end of the light shielding frame. At least the first, which constitutes at least two opposing sides
The upper and lower sides are straight lines on the front end side.
An opening whose right side protrudes in an arc shape on the inside is formed, and a second frame for preventing flare that integrally blocks harmful light that is not directed to the exposure opening out of light that has passed through the taking lens is integrally formed. .

[0008]

FIG. 1 shows an exploded view of a film unit with a lens for taking a picture in an exposure range of an aspect ratio (approximately 1.8) of an HDTV screen, and a unit body 3 is a body incorporating a simple photographing mechanism. The front cover 5 and the rear cover 6 are attached to the section 4. The main body 4 is formed with a patrone chamber 8 for accommodating a patrone 7 and a film roll chamber 10 for accommodating an unexposed film 9 drawn from the patrone 7 in a roll shape. An exposure opening 12 of a standard size (“24 mm × 36 mm”) is formed between the patrone chamber 8 and the film roll chamber 10 to regulate an exposure range of the exposure position for the film 9, and to be in front of the exposure opening 12. Is formed integrally with the dark box 13.

A light-shielding frame 15 is fitted and fixed inside the dark box 13 through the exposure opening 12. For this reason, as shown in FIG. 2, a projection 16 for positioning and a pin 17 are provided on the inner wall of the dark box 13, and the pin 17 is passed through a hole 18 formed on the front side of the light shielding frame 15. Thereafter, the head of the pin 17 is thermally caulked. The light-shielding frame 15 is made of an integrally molded plastic article, and as shown in FIG. 3, a flare-preventing frame 20 is formed on the front end side, and a pair of upper and lower frame pieces are formed on the rear end side. 21 is formed to protrude. It is preferable that antireflection grooves 22 are provided on the inner wall of the light shielding frame 15 at a fine pitch as shown in the figure.

The upper and lower outer peripheral edges 21 a of the frame piece 21 are in close contact with the upper and lower sides of the exposure opening 12 when the light shielding frame 15 is fitted into the dark box 13. Therefore, this light-shielding frame 1
5, a new exposure opening obtained by using 5 has long sides opposed vertically, which are regulated by the inner periphery 21b of the frame piece 21.
The short sides facing each other are regulated by the short sides of the exposure frame 12 itself. The width D1 of the frame 21 is 2
Since this is set to mm, the size of the new exposure aperture is “20 mm × 36 mm”, which is the exposure range on the film surface. The aspect ratio of this exposure range is 1.8.
Thus, the aspect ratio becomes the same as that of the HDTV screen.

On the other hand, the flare prevention frame 20 provided on the front end side of the light-shielding frame 15 has an opening 25 in which the upper and lower sides are straight, and the left and right sides project inwardly in an arc shape. Then, as shown in FIG. 3, the aspect ratio of the area surrounded by the broken line passing through the vertices of the side protruding in the arc shape and the upper and lower straight sides is 1.8, which is the same as the HDTV screen. According to the flare prevention frame 20 having such an opening 25,
As shown in FIG. 2, of the light passing through the taking lens 26 and the aperture 27 when the shutter blade 24 is opened,
Since light directed directly to the film 9 is passed and light from outside the effective angle of view range is cut, for example, as shown by a broken line, stray light causing flare can be reduced. Note that the left and right vertical sides of the opening 25 may also have a linear shape as shown by a broken line in FIG.

The light-shielding frame 30 shown in FIG. 5 is used to make a film unit with a lens for panoramic photography. Like the light-shielding frame 15 described above, the light-shielding frame 30 is placed in the dark box 13 as shown in FIG. It is attached. The light shielding frame 30 has a flare prevention frame 31 formed on the front end side, and a pair of frame pieces 32 projecting from the rear end side only up and down, facing each other. The width D2 of each of the frame pieces 31 is set to about 5.2 mm. When the frame pieces 31 are fitted into the dark box 13, the upper and lower outer peripheral edges 32a are exposed to the exposure opening 1 like the light shielding frame 15.
Closely contact the upper and lower sides of 2. Therefore, this light shielding frame 3
The size of the new exposure aperture obtained by using 0 is “13.7 mm × 36 mm”, and a panorama size exposure range can be obtained on the film surface.

The opening 33 formed in the flare prevention frame 31 on the front end side has a shape similar to the above-described panorama size exposure range when the left and right vertical sides are regarded as straight lines such as broken lines, and has an aspect ratio. It is about 2.6. The flare prevention frame 31 having the opening 33 cuts light outside the effective angle of view determined by the photographing lens 26, the aperture 27, and the panorama size exposure opening, and reduces stray light in the dark box 13.

The assembling of a film unit with a lens using the light shielding frames 15 and 30 will be described.
If there are three types of film units with lenses, one with a standard exposure opening, one with an exposure opening with an aspect ratio of 1.8, and one with an exposure opening with an aspect ratio of 2.6, the unit body 3 is The main parts 4, the front cover 5, and the rear cover 6, which are the main components, are manufactured as completely common regardless of the model.

When making a film unit with a lens having an exposure opening having an aspect ratio of 1.8, a light-shielding frame 15 is fitted and fixed in a dark box 13 through an exposure opening 12 formed in advance in the main body 4. . This allows
Only the upper and lower sides of the exposure opening 12 are filled in by 2 mm by the frame piece 21 to form a new exposure opening having a size of “20 mm × 36 mm”. Since the light-shielding frame 15 is provided integrally with the flare-preventing frame 20 having an opening 25 having a shape similar to the shape of the new exposure opening, if the light-shielding frame 15 is assembled, the flare-preventing frame is separately provided. There is no trouble to incorporate. Further, when a film unit with a lens having an exposure opening for panoramic photography is manufactured, it is only necessary to incorporate the light shielding frame 30 in place of the light shielding frame 15 in the commonly manufactured main body 4.

Further, when producing a film unit with a lens having a standard size exposure aperture, the light shielding frames 15 and 3 are required.
The front cover 5 and the rear cover 6 may be directly attached to the main body 4 without using any of the above. The inner wall of the dark box 13 of the main body 4 has a structure in which stray light hardly enters the exposure opening of the standard size. However, if necessary, a flare prevention frame adapted to the shape of the exposure opening 12 is provided on the front end side. Alternatively, another light-shielding frame having a rear end side shape that does not change the size of the exposure opening 12 may be incorporated.

Although the description has been given above with reference to the illustrated embodiment, the size of the exposure opening 12 formed in the main body 4 in advance does not necessarily have to match the standard size. You may keep it large. Then, the outer peripheral edge of the rear end side of the various light-shielding frames is made according to the opening size, and when assembling a film unit with a lens having a standard size exposure opening, a frame piece having a predetermined width is also used up and down. What is necessary is just to incorporate the light shielding frame provided with. Furthermore, it is also possible to make the exposure opening 12 of the main body 4 larger than the standard size both vertically and horizontally, and to determine the size of the new exposure opening only by the rear end shape of the light shielding frame. Further, the light-shielding frame of the present invention can be used for an exposure opening having a shape other than the above-described aspect ratio, and can also be applied when switching a horizontally long standard size exposure opening to a vertically long half size exposure opening. Of course.

[0018]

As described above, in addition to the first frame for determining the exposure aperture, the upper and lower
Opening with sides straight and left and right sides projecting in an arc inward
Since the second frame for preventing flare is integrated, the flare preventing frame suitable for the exposure opening can be obtained only by incorporating the light shielding frame into the unit body. Even if the size of the exposure opening formed in the unit main body is made common, the desired exposure opening size can be obtained only by changing the light shielding frame, so that the unit main body can be shared. Thus, the manufacturing cost of the film unit with the lens can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part of a film unit with a lens using the present invention.

FIG. 2 is a sectional view of a main part of a unit main body in which a first light shielding frame is incorporated.

FIG. 3 is an external view of a rear end side of a first light shielding frame.

FIG. 4 is a sectional view of a main part of a unit main body in which a second light shielding frame is incorporated.

FIG. 5 is an external view of a rear end side of a second light shielding frame.

[Explanation of symbols]

 3 Unit Main Body 4 Main Body 9 Film 12 Exposure Opening 15 Light-Shielding Frame 20 Flare Prevention Frame 21 Frame Piece 25 Opening 26 Photo Lens 30 Light-Shielding Frame 31 Flare Prevention Frame 32 Frame Piece 33 Opening

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03C 3/00 G03B 17/04

Claims (1)

(57) [Claims] 1. A lens in which a film is pre-loaded on a unit body incorporating a photographing mechanism such as a photographing lens and a shutter.
A light-shielding frame for a lens-equipped film unit provided in a lens-equipped film unit, wherein the exposure range of the film is limited by the exposure opening on the front surface of the film. The upper and lower sides are formed as straight lines, and the left and right sides are formed as arcs inward on the front end side formed toward the photographing lens.
A film unit with a lens , wherein a projected frame is formed, and a second frame for preventing flare, which blocks harmful light that is not directed to the exposure aperture among light passing through the taking lens, is integrally formed. Light-shielding frame.