JPH08114895A - Production of light shielding chamber for camera - Google Patents

Abstract

PURPOSE: To produce a light shielding chamber which suppresses the formation of flares. CONSTITUTION: The resin light shielding chamber 13 flaring from an aperture for exposure toward a film surface side to a taper shape is formed. Projecting lines 22 are formed to a staircase shape on the inside wall surface of the light shielding chamber 13. Staircase-shaped projection lines 23 are formed on a processing head 26. While the projecting lines 22 of the light shielding chamber 13 are dissolved by a processing head 26, the projecting lines are pushed in and the dissolved resin is built up in the spacings 26c between the staircase- shaped projecting lines 23 of a processing jig 26 and the projecting lines 22 of the light shielding chamber 13. Projecting lines 30 for diffusing the light reflected on the inside surfaces are formed by these build-ups. Then, the light reflected on the inside surfaces is effectively diffused by the projecting lines 30 for diffusing the light reflected on the inside surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a camera shading chamber in which a member for effectively diffusing and attenuating internally reflected light is formed on the inner wall surface of the camera shading chamber integrally formed of resin. Is.

[0002]

2. Description of the Related Art A light-shielding chamber provided in a camera allows only light passing through a lens to reach a film surface and blocks other light. This is manufactured by injecting a resin in a fluid state into a combination of a mold on the concave side forming the outer wall of the light shielding chamber and a mold on the convex side forming the inner wall of the light shielding chamber. Then, when shooting, in order to prevent flare that occurs when the light obliquely entering the shooting lens is reflected on the inner wall surface and reaches the film surface, a step-shaped protrusion is formed on the mold on the convex side. A stair-shaped projection is integrally formed on the inner wall surface of the light-shielding chamber. Thereby, the light obliquely entering the photographing lens is repeatedly reflected and diffused between the ridges and attenuated. However, in this case, when particularly strong light such as sunlight at daytime enters, a sufficient diffusion effect cannot be obtained and flare occurs.

It is also conceivable to use a convex mold having a large number of small holes formed on the surface of the above-mentioned step-shaped projections and to form a large number of embosses on the surface of the projections for diffusing internally reflected light. However, in this case, there is a problem that the surface of the embossing is scraped when the die on the convex side is extracted, and whitening or scratches are likely to occur. Therefore, flocking paper is also attached to the wall surface of the light-shielding chamber as is done with a general camera.

[0004]

However, if the flocked paper is attached to the wall surface of the light-shielding chamber, a considerably high flare prevention effect can be obtained, but the flocked paper requires a lot of time and effort, so that the cost is increased. . Further, it is not suitable to be used for a product such as a lens-fitted film unit in which recycling characteristics are important because different materials are mixed.

The present invention is intended to solve the above problems, and provides a method of manufacturing a light-shielding chamber for a camera which effectively suppresses the occurrence of flare at low cost.

[0006]

In order to achieve the above object, in the method for manufacturing a light-shielding chamber for a camera according to claim 1, a taper that gradually expands from the opening on the photographing lens side toward the opening on the film side. A light-shielding chamber made of resin with a cylindrical inner wall surface is provided, and the step-shaped protrusion of a jig with a plurality of step-shaped projections is pressed against the inner wall surface of the camera light-shielding chamber to heat the camera. The jig is pushed in while melting the jig abutting part on the inner wall surface of the light-shielding chamber, and the melted resin is raised in the gap between the inner wall surface of the camera light-shielding chamber and the stair-shaped protrusion of the jig, and the raised portion is removed. It is a ridge for internally reflected light diffusion.

According to a second aspect of the present invention, there is provided a camera light-shielding chamber manufacturing method, wherein the inner wall surface is tapered so that the inner wall surface gradually expands from the opening on the photographing lens side toward the opening on the film side. A resin-made light-shielding chamber for a camera is formed by integrally molding a plurality of ridges, and the step-like protrusions of a jig with a plurality of step-like ridges formed in this camera light-shielding chamber are pushed onto the ridges of the camera light-shielding chamber. Apply heat by applying and pressing the jig while melting the jig contact part on the inner wall surface of the light shielding room for the camera,
The melted resin is raised in the gap between the inner wall surface of the light-shielding chamber for the camera and the step-shaped protrusion of the jig, and the raised portion is used as the internal reflection light diffusion protrusion.

According to a third aspect of the present invention, there is provided a method of manufacturing a camera light-shielding chamber according to the first or second aspect of the present invention, wherein the jig contact portion of the camera light-shielding chamber is melted by ultrasonic waves. This is done by vibration.

[0009]

FIG. 4 is an exploded perspective view of a unit main body of a lens-fitted film unit embodying the present invention. The unit main body is composed of a front cover 3, a main body part 4, an exposure unit 5, a photographic film 7 and a cartridge 8, and a rear cover 9, and the front cover 3, the main body part 4, the exposure unit 5 and the rear cover 9 are recycling characteristics. In consideration of the above, resin molded products are mainly used.

A box-shaped light-shielding chamber 13 is formed in the center of the main body 4. An exposure unit 5 incorporating a taking lens 16 and a film winding mechanism is attached to an exposure opening 14 formed on the front surface of the light-shielding chamber 13. After the exposure unit 5 is attached, the front cover 3 integrally formed with the release button is attached to the front surface of the main body portion 4, and the cartridge storage chamber 19 and the film roll chamber 20 formed on both sides of the light shielding chamber 13 are connected to the cartridge 8 and the cartridge 8 respectively. Photo film 7
When they are respectively stored, they are light-tightly closed by the rear cover 9.

As shown in FIG. 1, the light-shielding chamber 13 has a tapered inner wall surface which gradually expands from the exposure opening 14 toward the film surface side. The processing device 25 for processing the light-shielding chamber 13 includes a processing jig 26, a pushing portion 27 to which the processing jig 26 is assembled, and a holding portion 24 that holds the main body portion 4 when processing the light-shielding chamber 13. Has been done. The pushing portion 27 is moved up and down by a hydraulic cylinder (not shown), and an ultrasonic head 28 is built in the attachment portion of the processing jig 26. When the processing head 26 is pressed against the inner wall surface of the light shielding chamber 13 by the pressing portion 29, the ultrasonic head 28 vibrates ultrasonically in the direction along the contact surface, and frictional heat is generated at the contact portion.

As shown in FIG. 2 (A), a plurality of step-shaped projections 22 are integrally formed on the inner wall surface of the light shielding chamber 13. The ridge 22 is an orthogonal surface 22a orthogonal to the optical axis of the light-shielding chamber.
And a horizontal plane 22b parallel to the optical axis. The outer wall surface of the processing jig 26 is in contact with the surface 22a,
A plurality of step-shaped projections 23 having a gap 26c between the projections 22 and 2b are integrally formed at the same pitch as the projections 22 of the light-shielding chamber 13.

Next, the operation of the above embodiment will be described. As shown in FIG. 1, the main body part 4 is taken out after pouring a resin in a fluid state into an injection molding die after a lapse of a certain time, and the film roll chamber 20, the cartridge storage chamber 19, the light shielding chamber 13, and the winding knob are rotated in reverse. Preventive claws are integrally molded. At this time, a plurality of step-shaped projections 22 are integrally formed on the inner wall surface of the light shielding chamber 13.

When the body portion 4 is set on the holding portion 24,
The pushing portion 27 descends and the processing jig 26 is pushed into the light-shielding chamber 13, and the step-shaped projection 23 is pressed against the orthogonal surface 22a as shown in FIG. 2 (A). Next, the contact surface is rubbed by ultrasonic vibration, and the ridge 22 is melted by the friction heat. Since the processing jig 26 is pushed into the light-shielding chamber 13 while melting the protrusion 22, the softened portion rises in the gap 26c as shown in FIG. 2B, and the inner surface reflected light diffusion protrusion 30 is formed. . Since the inner surface reflected light diffusing ridges 30 are formed by rising a softened resin, the surface is rough and the light diffusing property is improved.

Next, the pushing portion 27 is raised and the processing jig 26 is separated from the light shielding chamber 13. Inner surface reflected light diffusion ridge 30
Since it is formed in the gap 26c, the surface of the internally reflected light diffusion ridge 30 is not scraped when the processing jig 26 is pulled out, so that whitening or scratches do not occur.

The exposure unit 5 is attached to the main body 4 having the light-reflecting light diffusion projections 30 formed in the light-shielding chamber 13 in the assembly line of the lens-fitted film unit. Also, the cartridge storage room 19 and the film roll room 2
A photo film 7 and a cartridge 8 are stored in 0. Further, the front cover 3 and the rear cover 9 are attached, the assembly of the unit main body is completed, and then the unit main body is covered with a paper box.

When taking a picture with the lens-fitted film unit, the photographer first turns the winding knob to wind the film. In conjunction with this film winding,
When the shutter is charged and the film for one frame is wound up, the winding stop mechanism operates to lock the winding. After that, framing is performed by looking through the finder, and by pressing the release button, the shutter blades are driven to open and close to take a picture.

When the shutter blades are opened and closed, the subject light passes through the taking lens and the exposure aperture, and is imaged on the photographic film. At this time, strong light, such as sunlight at daytime or illumination light from the ceiling, may enter the inner wall surface of the light-shielding chamber 13 through the taking lens as shown in FIG. 2C. Most of the light is diffused and attenuated by the inner surface reflected light diffusing ridges 30, so that it hardly reaches the photographic film. Therefore, the occurrence of flare is suppressed and a good image can be obtained.

Further, in place of the projection 22 formed on the inner wall surface of the light shielding chamber 13, the inner wall surface 44 of the light shielding chamber 41 may be flat as shown in FIG. 3 (A). In this case, the processing jig 42 having the step-shaped protrusion 43 is pressed against the inner wall surface 44 of the light-shielding chamber, and the protrusion 4 is formed in the same manner as described above.
Processing jig 4 while melting the contact part of 3 by ultrasonic vibration
Press 2. As shown in FIG. 3B, the melted portion rises in the gap 45 between the inner wall surface 44 and the protrusion 43 to form the inner surface reflected light diffusion protrusion 50. As shown in FIG. 3C, the subject light is diffused, attenuated, and absorbed by the curved surface of the inner surface reflected light diffusion projection 50. The same components as those in the above embodiment are designated by the same reference numerals.

The pressing stroke of the processing jig in each of the above embodiments may be two thirds or less of the horizontal plane of the ridge of the processing jig. In this case, diffusion and reflection of the subject light can be effectively performed. The diffusion portion for preventing internal reflection is formed at a height that can be achieved.

In each of the above embodiments, the stepwise inner surface reflected light diffusing ridges are formed on the entire inner peripheral surface of the light-shielding chamber, but they may be formed only on the surface where the flare becomes strong. Further, a heating device such as a heater may be used as the processing jig, and the heated processing jig may be pressed against the light-shielding chamber to process the inner surface reflected light diffusion portion. In addition, the stepwise ridges of the processing jig have a pitch different from that of the ridges formed stepwise on the inner wall surface of the light-shielding chamber, and, for example, an inner surface reflected light diffusion ridge is provided at every other ridge of the light-shielding chamber. You may form. Further, when the processing jig 52 having a plurality of tapered surfaces formed on each stepped surface as shown in FIG. 5 is used as the processing jig, an inner surface reflection light diffusion ridge having a higher light diffusion efficiency can be obtained. Can be formed.

In the above embodiment, the case where the light-shielding chamber of the lens-fitted film unit is manufactured is shown. However, the present invention may be carried out when manufacturing the light-shielding chamber of a general camera or the like.

[0023]

According to the present invention, since the jig is pressed against the wall surface of the light shielding chamber and the wall surface of the light shielding chamber is pushed in while being melted, the melted portion rises in the gap between the wall surface of the light shielding chamber and the jig. The inner surface reflected light diffusion ridge is easily formed. Therefore, it is possible to manufacture a light-shielding chamber that can effectively prevent flare due to strong light from the light source without cost. Moreover, it is not necessary to use another material such as flocked hair, and the recyclability is improved.

Further, in the method for manufacturing a light-shielding chamber for a camera according to claim 1 or 2, since the jig contact portion of the light-shielding chamber for the camera is melted by ultrasonic vibration, fine unevenness is formed on the melting ridge surface. As a result, the diffusivity of the light reflected on the inner surface can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an apparatus for forming an internal reflection light preventing ridge in a light-shielding chamber.

2 (A) and 2 (B) are enlarged cross-sectional views showing a main part of a state in which an inner surface reflected light diffusing ridge is formed on a wall surface in which the ridge is formed stepwise. FIG. 4 is an explanatory diagram showing the diffusivity of the inner surface reflected light diffusing ridge.

3 (A) and 3 (B) are enlarged cross-sectional views showing a main part of a state in which an internally reflected light diffusion ridge is formed on a wall surface formed by a flat surface, and FIG. 3 (C) is an internal reflection. It is explanatory drawing which shows the diffusivity by a light diffusion ridge.

FIG. 4 is an exploded perspective view of a film unit with a lens.

FIG. 5 is a perspective view showing a part of another processing jig.

[Explanation of symbols]

 13 Light-shielding chamber 22 Protrusion 22a Orthogonal surface 22b Horizontal plane 23,43 Stepwise protrusion 25 Processing device 26,42 Processing jig 26c, 45 Gap 28 Ultrasonic head 30,50 Internal reflection light diffusion protrusion

Claims (3)

[Claims] 1. A resin light-shielding chamber for a camera having a tapered inner wall surface that gradually expands from the opening on the side of the taking lens toward the opening on the side of the film is provided, and a plurality of stair-like ridges are formed. The stepped projection of the jig is pressed against the inner wall surface of the camera light-shielding chamber to heat it, and the jig is pushed in while melting the jig contact part on the inner wall of the camera light-shielding chamber, and the melted resin is used for the camera. A method for manufacturing a light-shielding chamber for a camera, characterized in that it is raised in a gap between an inner wall surface of the light-shielding chamber and a stair-shaped protrusion of a jig, and the raised portion is used as an inner surface reflected light diffusion protrusion. 2. A resin camera having a tapered inner wall surface that gradually expands from the opening on the side of the taking lens toward the opening on the side of the film, and a plurality of step-shaped protrusions are integrally formed on the inner wall surface. A light-shielding chamber for cameras is provided, and the step-like protrusions of a jig in which a plurality of step-like protrusions are formed are pressed against the protrusions of the camera light-shielding chamber to heat the inner wall surface of the camera light-shielding chamber. The jig is pushed in while melting the contact area of the jig, and the melted resin is raised in the gap between the inner wall surface of the light-shielding chamber for the camera and the step-shaped projections of the jig, and the raised portion is reflected by the internal reflection light. A method for manufacturing a light-shielding chamber for a camera, which is characterized by: 3. The method of manufacturing a light-shielding chamber for a camera according to claim 1, wherein the jig contact portion of the light-shielding chamber for camera is melted by ultrasonic vibration. Method.