JPH01185536A - Constitution of light shielding chamber for camera - Google Patents

Abstract

PURPOSE:To effectively and in short time accomplish manufacturing by composing the bottom surface part of a light shielding chamber of a part of a camera body and composing the upper surface part of the light shielding chamber of an other member fitted on the camera main body. CONSTITUTION:The bottom surface part of the light shielding chamber 30 is composed of the part 1b of the camera main body 1, and the upper surface part of the light shielding chamber 30 is composed of the latter half part 2c of a sprocket supporting board 2. Multi-sawtooth projecting parts 1f and 2h which are tilted in the front direction are formed on the surfaces of the 1b and of the 2c, that is on the bottom and ceiling surfaces of the light shielding chamber 30. Therefore, this light sealing chamber 30 is assembled and accom plished at the same time when the other part is assembled in camera body assembling process, and such additional work as shade coating, etc., becomes unnecessary. Thus, light shielding chamber forming work can be performed more effectively and in shorter time than ordinary light shielding chamber forming process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the structure of a light-shielding chamber or aperture chamber of a camera.

[Prior Art] In conventional cameras, the light-shielding chamber or aperture chamber for guiding the light flux that has passed through the photographing lens to the imaging plane generally has one of the following two types of structures. It is organized by format.

(a) The aperture chamber is formed integrally with the camera body, and the inner wall surface of the aperture chamber is coated with a light-shielding coating (matte coating for preventing light reflection), or a light-shielding tape is applied to the inner wall surface.

(b) Applying a light-shielding coating to an aperture member formed separately from the camera body, and incorporating it into the camera body to form a light-shielding chamber (aperture).

[Problems to be Solved by the Invention] However, the conventional structure described above has the following problems.

In the case of structure (a) above, when applying light-shielding coating to the inner wall surface of the aperture chamber, it is necessary to mask the film rail surface and other parts to prevent the paint S from adhering to the film rail surface, and this masking work prevents the painting work. The efficiency was very low and therefore the cost of forming the blackout chamber was quite high.

On the other hand, in the structure (a) above, in the case of a structure in which the light-shielding tape is attached to the inner wall of the aperture chamber, it is necessary to apply it accurately so that the light-shielding tape does not protrude to the rear of the camera body or hit the photographic film. The work efficiency is poor because the worker has to insert his finger into a small aperture opening and apply the tape accurately.Therefore, as with the method of applying light-blocking paint, the cost of forming the light-blocking chamber is quite high. It was expensive.

Also, when forming a light-shielding chamber ``C'' using the structure type (b) above, the material cost, assembly cost, and light-shielding painting cost for the aperture member are required, so forming the light-shielding chamber is similar to the structure type (a) above. The cost was high.

Therefore, instead of applying light-shielding paint or pasting light-shielding tape, a method of forming a large number of parallel protrusions 16 (light-shielding lines) on the inner wall surface of the aperture chamber 30 as shown in FIG. 8 may be considered. ing.

In this method, when molding the aperture chamber '30, it is necessary to pull out the mold toward the rear of the camera in the direction of arrow C in FIG. It must be composed of two surfaces, a surface tab parallel to the optical axis and a surface 18a orthogonal to the optical axis, but when the protrusion 16 is formed from two surfaces perpendicular to each other in this way, the aperture chamber 30 is The light 15 entering in the direction of the arrow hits the surface 16b of the protrusion 16 parallel to the optical axis, is reflected in the direction of the arrow, and enters the imaging plane, potentially causing flare. Therefore, in order to prevent such reflection from occurring, as shown in FIG. Although it is theoretically desirable to form such a serrated protrusion 17 on the inner wall surface of the aperture chamber 30, when forming the aperture chamber 30, the mold should be pulled out in the direction of arrow C in the figure. As a result, the design of the camera body and the structure of the molding die must be made extremely complicated, resulting in a significant increase in cost and making it impossible to put it into practical use.

It is an object of the present invention to provide a structure for a camera body portion that can be manufactured at a lower cost than any of the above-mentioned structural types, and more particularly, can be manufactured at a lower cost than conventional structures. The object of the present invention is to provide a camera light-shielding chamber (aperture chamber) structure.

[Means for Solving the Problems] In the light-shielding room structure according to the present invention, at least the bottom part of the constituent wall surfaces of the light-shielding room is made up of a part of the camera body, while the top part (ceiling surface part) of the light-shielding room is made up of a part of the camera body. ) is constituted by other members attached to the camera body, and is characterized in that a light-shielding protrusion is formed on the inner wall surface of the light-shielding chamber, so that no light-shielding coating is required.

[Function] In the light-shielding chamber structure according to the present invention, the light-shielding chamber is composed of an assembled structure, and the light-shielding chamber is assembled and completed at the same time as other parts are assembled in the camera body assembly process, and addition of light-shielding coating, etc. Since no manual work is required, the light-shielding chamber can be formed much more efficiently and in a shorter time than the conventional light-shielding chamber forming process, and the light-shielding chamber can be formed at a lower cost than before.

[Example] The present invention will be described in detail below with reference to FIGS. 1 to 5.

FIG. 1 is an exploded perspective view showing a part of the camera body structure of a camera with switchable screen dimensions to which the present invention is applied. In FIG. 1, 1 is a camera body, 2 is a sprocket support plate configured to support a film feeding sprocket (described later) and to be fastened to the top surface of the camera body 1 with screws 5 and 6; Reference numeral 4 denotes a photographic screen size changing plate having bins 3a and 4a inserted into pin holes 2a and 2b of the support plate 2. It should be noted that the photographing screen size changing plates 3 and 4 and the photographing screen size changing device related thereto are not related to the present invention, and therefore a description thereof will be omitted.

The camera body 1 has a cartridge storage chamber and a spool chamber on both sides thereof, and a finger member 1h having both ends fixed to the outer walls of both chambers is disposed between the cartridge storage chamber and the spool chamber. A screw hole for fastening to the sprocket support plate 2 is provided in the finger member 1h.

An upwardly opening opening 1a is formed between the front plate 1j of the camera body 1 and the finger member 1h.
A is used as an opening for pulling the mold upward during molding of the camera body 1. Also, when assembling the camera body, the photographing screen size changing plates 3 and 4 are inserted into the opening 1a, and the chain plates 3 and 4 are placed behind the photographing lens and at the rearmost part of the light-shielding chamber.Note that 1e is for sprocket support. The receiver for receiving the plate 2 is a part.

FIG. 2 shows a longitudinal section of the center of the camera body with a sprocket support plate 2 mounted on the camera body 1 and a film feeding sprocket 7 mounted on the sprocket support plate 2.

As shown in FIG. 2, the bottom part of the light-shielding chamber 30 (aperture chamber) is composed of the portion 1b of the camera body 1, and the light-shielding chamber 30
The upper surface portion (top plate portion) of is constituted by the rear half portion 2c of the sprocket support plate 2. On the surfaces of the portions 1b and 2c (ie, the bottom and ceiling surfaces of the light-shielding chamber 30), a large number of sawtooth-shaped protrusions 1f and 2h (J rays) tilted toward the front are formed.

A raised portion 1c is formed at the front end of the horizontal portion 1b constituting the bottom surface of the light-shielding chamber 30;
The upper surface is a rearwardly inclined (diameter expanding) inclined surface, and a plurality of serrated protrusions 1 are also inclined forward on the inclined surface.
f is formed.

The opening edge 1g at the rear end of the light-shielding chamber 30 is a tapered surface that slopes (increases in diameter) toward the rear. Therefore, even if the surface of the mold is subjected to matte treatment, the light-shielding chamber 30
The mold can be easily pulled out backwards during molding. In addition, if this opening edge 1g is made up of a plane parallel to the optical axis, if the mold is treated with matte to make it matte, the mold will not be easily removed, and there will be problems when removing the mold. Scratches occur on the edge of the opening, resulting in the edge of the opening becoming a glossy surface, which has an adverse effect on photographs taken as described below.

FIG. 6 shows a case where the aperture edge 1g is composed of a surface parallel to the optical axis and is a glossy surface for the above-mentioned reason. In this case, the film 1 passes through the photographing lens 9.
Since the light beam 11 in the diagonal direction toward 0 is reflected in the direction of the arrow by the aperture edge 1g and exposes the peripheral area of the screen, a similar high-brightness area is created around the completed photograph 12 as shown in FIG. 1
3 occurs, and even if an image existing at the position of the high-brightness area 13 is photographed, this results in flare being in the high-brightness area. Therefore, even if the image is captured, there will be a high-intensity flare area, and the resulting photo will look grainy and look strange.

In this embodiment, since the rear opening edge 1g of the light-shielding chamber 30 is configured as a tapered surface whose diameter increases toward the rear as described above, a matte treatment is applied to the surface of the mold to make it matte. When molding the light-shielding chamber 30, the mold can be easily pulled out backwards, so that the surface of the opening edge 1g is formed as a matte surface, so that the frame-like photograph described above does not occur.

Here, referring again to FIG. 2, the structure of the camera body 1, the sprocket support plate 2, and other members related to the light shielding chamber will be explained.

As shown in FIG. 2, the horizontal portion of the camera body 1 that supports the front half 2e of the sprocket support plate 2 above the photographic lens 9 has a light-shielding recess 1i (or groove) on its upper surface. A protrusion 2d that fits into the recess 11 is formed on the lower surface of the front half 2e of the sprocket support plate 2.
(or ridges) are formed. Due to the formation of the recess 11 and the protrusion 2d, light rays entering the mating surface of the camera body 1 and the sprocket support plate 2 from the direction of arrow A are prevented from proceeding rearward in the recess 11. Therefore, leakage of harmful light into the light-shielding chamber 30 is completely prevented.

The rear half 2C of the sprocket support plate 2 constitutes the ceiling surface of the light-shielding chamber 30 as described above, but the front half 2C
It is bent so that it is at a lower position than e. A hole 2g is formed on the upper surface of the second half portion 2C to rotatably fit the shaft portion of the film feeding sprocket 7, and the sprocket 7 is rotatable about the vertical axis on the second half portion 2c. is supported by

Reference numeral 8 denotes a sprocket cover disposed above the sprocket 7, and the sprocket cover 8 has a stepped portion 1d formed on the camera body 1 and a stepped portion 2f formed at the rear end of the front half of the sprocket support plate on the outer periphery of the sprocket cover 8. Flange portions 8a and 8b are formed to be supported by the sprocket cover 8, and the sprocket cover 8 is fitted and supported by the step portions 1d and 2f. Since the fitting surfaces of the stepped portions 1d and 2f and the sprocket cover 8 are bent in a crank shape, the light beam traveling from the direction of arrow B in the figure is blocked at the stepped portions 1d and 2f.
Therefore, no light leaks into the light-shielding chamber 30 from the B direction.

FIG. 3 is a horizontal sectional view of the light shielding chamber 30 when the present invention is applied to the camera with the screen size changing plate shown in FIG. In the camera having the above structure, the screen size changing plates 3 and 4 are arranged in the light-shielding chamber (aperture room), so the surfaces of the screen size changing plates 3 and 4 are arranged in order to prevent generation of harmful reflected light from the surfaces thereof. Serrated ridges 3b and 4b (shading lines) are also formed on the serrations.

FIG. 4 is a horizontal sectional view of a light shielding chamber (aperture chamber) 30 of a general camera without a screen size changing device, and in this embodiment, two side walls of the light shielding chamber 30 are formed integrally with the camera body 1, A forward-slanted sawtooth protrusion 1f is formed on the side wall, and a sawtooth protrusion if is also formed on the bottom surface of the light-shielding chamber 30 as in the previous embodiment.

FIG. 5 is an explanatory diagram for determining theoretical values such as the height and angle of inclination of the serrated protrusions 23 formed on the inner wall surface of the light-shielding chamber 30 (aperture chamber). In FIG. 5, the front surface of the serrated ridge 23 is 18, the rear surface is 19, the angle that the surface 19 makes with the optical axis 15 is α, and the front opening edge 20 of the lens barrel 20
a and the angle β that the light ray 22 that entered through the lip 21a of the aperture 21 at its maximum opening makes with the optical axis 15, and the surface 18 is the optical axis 1.
5, the angle formed with the plane perpendicular to 5 is δ, and the rear opening edge 3 of the light-shielding chamber 30
A line segment 24 connecting 0a and the apex of the serrated ridge 23 is the optical axis 1
Let γ be the angle made with the plane perpendicular to 5, then α>β, γ>δ
By determining the height, angle of inclination, etc. of the serrated protrusions 23 so that the following occurs, it is possible to prevent harmful incident light from entering the film surface, and it is possible to take beautiful photographs without flare.

[Effects of the Invention] As explained above, in the light-shielding chamber structure (aperture structure) according to the present invention, at least the bottom portion of the wall surface of the light-shielding chamber is constituted by a part of the camera body, and Since the upper surface (ceiling surface) is constructed of other members attached to the camera body, it can be manufactured more efficiently and in a shorter time than the conventional light-shielding chamber structure. In particular, according to the light-shielding chamber structure according to the present invention, the light-shielding chamber can be assembled and completed during the assembly process of the camera body, and additional work such as light-shielding painting is not required, so the camera can be manufactured at a lower cost than in the past. be able to.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a main part of a camera having a light-shielding chamber structure according to the present invention, FIG. 2 is a vertical cross-sectional view of a main part of the camera shown in FIG. Figure 4 is a horizontal cross-sectional view of the light-shielding chamber of the camera, which is different from the camera shown in Figure 1. An explanatory diagram for deriving the theoretical values of dimensions and shapes; Figure 6 is a diagram for explaining harmful light incident on the film surface when the opening edge at the rear end of the light-shielding chamber is not tapered; Figure 7 6 is a diagram showing the state of the photograph taken in the state shown in FIG. 6, and FIG. 8 is a diagram for explaining the case where the cross-sectional shape of the shading line (protrusion) formed on the inner wall surface of the shading chamber is a right angle. , FIG. 9 is a diagram for explaining the case where the cross-sectional shape of the light-shielding line is sawtooth. 1...Camera body 2...Sprocket support plate 3
and 4...Screen size changing plate 7...Sprocket 8 for film feeding...Sprocket cover 9...Photographing lenses 1f and 2h...serrated ridges (shading lines) Fig. 1

Claims (1)

[Claims] 1. In the structure of a cylindrical light-shielding chamber formed between a photographing lens and an image-forming surface so as to guide light that has passed through the photographing lens to an image-forming surface, 1. A light-shielding chamber structure for a camera, wherein at least a bottom portion of the light-shielding chamber is constituted by a part of the camera body, and an upper surface portion of the light-shielding chamber is constituted by another member mounted on the camera body. 2. The light-shielding chamber structure for a camera according to claim 1, wherein the left and right side portions of the light-shielding chamber are also formed from a part of the camera body.